A constituent of STRIATED MUSCLE and LIVER. It is an amino acid derivative and an essential cofactor for fatty acid metabolism.
An enzyme that catalyzes reversibly the conversion of palmitoyl-CoA to palmitoylcarnitine in the inner mitochondrial membrane. EC 2.3.1.21.
A key enzyme in SPHINGOLIPIDS biosynthesis, this enzyme catalyzes the pyridoxal-5'-phosphate-dependent condensation of L-SERINE and PALMITOYL COENZYME A to 3-dehydro-D-sphinganine. The enzyme consists of two different subunits.
A coenzyme A derivative which plays a key role in the fatty acid synthesis in the cytoplasmic and microsomal systems.
A fatty acid coenzyme derivative which plays a key role in fatty acid oxidation and biosynthesis.
Enzymes from the transferase class that catalyze the transfer of acyl groups from donor to acceptor, forming either esters or amides. (From Enzyme Nomenclature 1992) EC 2.3.
Acyltransferases in the inner mitochondrial membrane that catalyze the reversible transfer of acyl groups from acyl-CoA to L-carnitine and thereby mediate the transport of activated fatty acids through that membrane. EC 2.3.1.
An enzyme that catalyzes the formation of O-acetylcarnitine from acetyl-CoA plus carnitine. EC 2.3.1.7.
S-Acyl coenzyme A. Fatty acid coenzyme A derivatives that are involved in the biosynthesis and oxidation of fatty acids as well as in ceramide formation.
Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)
A long-chain fatty acid ester of carnitine which facilitates the transfer of long-chain fatty acids from cytoplasm into mitochondria during the oxidation of fatty acids.
A class of membrane lipids that have a polar head and two nonpolar tails. They are composed of one molecule of the long-chain amino alcohol sphingosine (4-sphingenine) or one of its derivatives, one molecule of a long-chain acid, a polar head alcohol and sometimes phosphoric acid in diester linkage at the polar head group. (Lehninger et al, Principles of Biochemistry, 2nd ed)
Organic compounds that include a cyclic ether with three ring atoms in their structure. They are commonly used as precursors for POLYMERS such as EPOXY RESINS.
An acetic acid ester of CARNITINE that facilitates movement of ACETYL COA into the matrices of mammalian MITOCHONDRIA during the oxidation of FATTY ACIDS.
A group of inherited disorders characterized by degeneration of dorsal root and autonomic ganglion cells, and clinically by loss of sensation and autonomic dysfunction. There are five subtypes. Type I features autosomal dominant inheritance and distal sensory involvement. Type II is characterized by autosomal inheritance and distal and proximal sensory loss. Type III is DYSAUTONOMIA, FAMILIAL. Type IV features insensitivity to pain, heat intolerance, and mental deficiency. Type V is characterized by a selective loss of pain with intact light touch and vibratory sensation. (From Joynt, Clinical Neurology, 1995, Ch51, pp142-4)
Organic, monobasic acids derived from hydrocarbons by the equivalent of oxidation of a methyl group to an alcohol, aldehyde, and then acid. Fatty acids are saturated and unsaturated (FATTY ACIDS, UNSATURATED). (Grant & Hackh's Chemical Dictionary, 5th ed)
Salts and esters of the 16-carbon saturated monocarboxylic acid--palmitic acid.
Lengthy and continuous deprivation of food. (Stedman, 25th ed)
The metabolic substances ACETONE; 3-HYDROXYBUTYRIC ACID; and acetoacetic acid (ACETOACETATES). They are produced in the liver and kidney during FATTY ACIDS oxidation and used as a source of energy by the heart, muscle and brain.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
Coenzyme A is an essential coenzyme that plays a crucial role in various metabolic processes, particularly in the transfer and activation of acetyl groups in important biochemical reactions such as fatty acid synthesis and oxidation, and the citric acid cycle.
A common saturated fatty acid found in fats and waxes including olive oil, palm oil, and body lipids.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
An enzyme that catalyzes the HYDROXYLATION of gamma-butyrobetaine to L-CARNITINE. It is the last enzyme in the biosynthetic pathway of L-CARNITINE and is dependent on alpha-ketoglutarate; IRON; ASCORBIC ACID; and OXYGEN.
Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.
A family of proteins involved in the transport of organic cations. They play an important role in the elimination of a variety of endogenous substances, xenobiotics, and their metabolites from the body.
The various filaments, granules, tubules or other inclusions within mitochondria.
Myoglobinuria is the presence of myoglobin, a protein found in muscle fibers, in the urine, which can occur due to muscle injury or disease, and may lead to acute kidney injury if excessive.
Errors in the metabolism of LIPIDS resulting from inborn genetic MUTATIONS that are heritable.
A group of 16-carbon fatty acids that contain no double bonds.
Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.
Members of the class of neutral glycosphingolipids. They are the basic units of SPHINGOLIPIDS. They are sphingoids attached via their amino groups to a long chain fatty acyl group. They abnormally accumulate in FABRY DISEASE.
Electron-dense cytoplasmic particles bounded by a single membrane, such as PEROXISOMES; GLYOXYSOMES; and glycosomes.
Covalent attachment of LIPIDS and FATTY ACIDS to other compounds and PROTEINS.
The rate dynamics in chemical or physical systems.
Derivatives of caprylic acid. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain a carboxy terminated eight carbon aliphatic structure.
The mitochondria of the myocardium.
Enzyme that catalyzes the first step of the tricarboxylic acid cycle (CITRIC ACID CYCLE). It catalyzes the reaction of oxaloacetate and acetyl CoA to form citrate and coenzyme A. This enzyme was formerly listed as EC 4.1.3.7.
A genus of gram-negative, aerobic, rod-shaped bacteria characterized by an outer membrane that contains glycosphingolipids but lacks lipopolysaccharide. They have the ability to degrade a broad range of substituted aromatic compounds.
A glycoside obtained from Digitalis purpurea; the aglycone is digitogenin which is bound to five sugars. Digitonin solubilizes lipids, especially in membranes and is used as a tool in cellular biochemistry, and reagent for precipitating cholesterol. It has no cardiac effects.
An enzyme that catalyzes the acyltransferase of SPHINGOSINE to N-acylsphingosine using acyl-COENZYME A as donor and COENZYME A as acceptor. The enzyme is mainly localized in the MITOCHONDRIA.
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.
Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.
A verocytotoxin-producing serogroup belonging to the O subfamily of Escherichia coli which has been shown to cause severe food-borne disease. A strain from this serogroup, serotype H7, which produces SHIGA TOXINS, has been linked to human disease outbreaks resulting from contamination of foods by E. coli O157 from bovine origin.
An amino alcohol with a long unsaturated hydrocarbon chain. Sphingosine and its derivative sphinganine are the major bases of the sphingolipids in mammals. (Dorland, 28th ed)
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A naturally occurring compound that has been of interest for its role in osmoregulation. As a drug, betaine hydrochloride has been used as a source of hydrochloric acid in the treatment of hypochlorhydria. Betaine has also been used in the treatment of liver disorders, for hyperkalemia, for homocystinuria, and for gastrointestinal disturbances. (From Martindale, The Extra Pharmacopoeia, 30th ed, p1341)
Antibiotic substance produced by Streptomyces garyphalus.
A carboxylating enzyme that catalyzes the conversion of ATP, acetyl-CoA, and HCO3- to ADP, orthophosphate, and malonyl-CoA. It is a biotinyl-protein that also catalyzes transcarboxylation. The plant enzyme also carboxylates propanoyl-CoA and butanoyl-CoA (From Enzyme Nomenclature, 1992) EC 6.4.1.2.
A class of sphingolipids found largely in the brain and other nervous tissue. They contain phosphocholine or phosphoethanolamine as their polar head group so therefore are the only sphingolipids classified as PHOSPHOLIPIDS.
Fatty acids which are unsaturated in only one position.
Azetidines are saturated, organic compounds containing a 4-membered ring with two carbon atoms and two nitrogen atoms (one as a secondary amine), which can be found in certain pharmaceuticals and natural substances, although they are less common than other cyclic amines.
A group of fatty acids that contain 18 carbon atoms and a double bond at the omega 9 carbon.
Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)
Pentanoic acid, also known as valeric acid, is a carboxylic acid with a 5-carbon chain (C5H10O2), having a distinctive pungent and rancid odor, found in some animals' sweat, certain foods, and produced through wood fermentation.
Compounds of the general formula R-O-R arranged in a ring or crown formation.
The muscle tissue of the HEART. It is composed of striated, involuntary muscle cells (MYOCYTES, CARDIAC) connected to form the contractile pump to generate blood flow.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
A subtype of striated muscle, attached by TENDONS to the SKELETON. Skeletal muscles are innervated and their movement can be consciously controlled. They are also called voluntary muscles.
An unsaturated fatty acid that is the most widely distributed and abundant fatty acid in nature. It is used commercially in the preparation of oleates and lotions, and as a pharmaceutical solvent. (Stedman, 26th ed)
A fibric acid derivative used in the treatment of HYPERLIPOPROTEINEMIA TYPE III and severe HYPERTRIGLYCERIDEMIA. (From Martindale, The Extra Pharmacopoeia, 30th ed, p986)
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.
An enzyme that catalyzes the first and rate-determining steps of peroxisomal beta-oxidation of fatty acids. It acts on COENZYME A derivatives of fatty acids with chain lengths from 8 to 18, using FLAVIN-ADENINE DINUCLEOTIDE as a cofactor.
Enzymes that reversibly catalyze the oxidation of a 3-hydroxyacyl CoA to 3-ketoacyl CoA in the presence of NAD. They are key enzymes in the oxidation of fatty acids and in mitochondrial fatty acid synthesis.
A flavoprotein oxidoreductase that has specificity for long-chain fatty acids. It forms a complex with ELECTRON-TRANSFERRING FLAVOPROTEINS and conveys reducing equivalents to UBIQUINONE.
A flavoprotein oxidoreductase that has specificity for medium-chain fatty acids. It forms a complex with ELECTRON TRANSFERRING FLAVOPROTEINS and conveys reducing equivalents to UBIQUINONE.
Triglycerides are the most common type of fat in the body, stored in fat cells and used as energy; they are measured in blood tests to assess heart disease risk, with high levels often resulting from dietary habits, obesity, physical inactivity, smoking, and alcohol consumption.
'Rats, Inbred BUF' is a strain of laboratory rats (Rattus norvegicus) that are selectively bred and inbred for research purposes, characterized by their uniform genetic background, high susceptibility to cancer, and frequent use in oncology and carcinogenesis studies.
Contractile tissue that produces movement in animals.
A strain of albino rat developed at the Wistar Institute that has spread widely at other institutions. This has markedly diluted the original strain.
RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.
Yeast-like ascomycetous fungi of the family Saccharomycetaceae, order SACCHAROMYCETALES isolated from exuded tree sap.
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
A nuclear transcription factor. Heterodimerization with RETINOID X RECEPTOR GAMMA is important to metabolism of LIPIDS. It is the target of FIBRATES to control HYPERLIPIDEMIAS.
Enzymes that catalyze the formation of acyl-CoA derivatives. EC 6.2.1.
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
An antilipemic agent that lowers CHOLESTEROL and TRIGLYCERIDES. It decreases LOW DENSITY LIPOPROTEINS and increases HIGH DENSITY LIPOPROTEINS.
The process of converting an acid into an alkyl or aryl derivative. Most frequently the process consists of the reaction of an acid with an alcohol in the presence of a trace of mineral acid as catalyst or the reaction of an acyl chloride with an alcohol. Esterification can also be accomplished by enzymatic processes.
A colorless liquid with a sharp burning taste and slight odor. It is used as a local anesthetic and to reduce pain associated with LIDOCAINE injection. Also, it is used in the manufacture of other benzyl compounds, as a pharmaceutic aid, and in perfumery and flavoring.
Glyoxylates are organic compounds that are intermediate products in the metabolic pathways responsible for the breakdown and synthesis of various molecules, including amino acids and carbohydrates, and are involved in several biochemical processes such as the glyoxylate cycle.
Purifying or cleansing agents, usually salts of long-chain aliphatic bases or acids, that exert cleansing (oil-dissolving) and antimicrobial effects through a surface action that depends on possessing both hydrophilic and hydrophobic properties.
An enzyme that transfers methyl groups from O(6)-methylguanine, and other methylated moieties of DNA, to a cysteine residue in itself, thus repairing alkylated DNA in a single-step reaction. EC 2.1.1.63.
Amidohydrolases that are specific for the cleavage of the N-acyl linkage of CERAMIDES. Ceramidases are classified as acidic, neutral or basic according to the optimal pH with which they function.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
FATTY ACIDS found in the plasma that are complexed with SERUM ALBUMIN for transport. These fatty acids are not in glycerol ester form.
A condition due to deficiency in any member of the VITAMIN B COMPLEX. These B vitamins are water-soluble and must be obtained from the diet because they are easily lost in the urine. Unlike the lipid-soluble vitamins, they cannot be stored in the body fat.
A group of MYCOTOXINS found in CORN contaminated with FUSARIUM fungus. They are chains of about 20 carbons with acidic ester, acetylamino and sometimes other substituents. They inhibit ceramide synthetase conversion of SPHINGOLIPIDS to CERAMIDES.
Diabetes mellitus induced experimentally by administration of various diabetogenic agents or by PANCREATECTOMY.
The chemical reactions involved in the production and utilization of various forms of energy in cells.
Necrosis or disintegration of skeletal muscle often followed by myoglobinuria.
A life-threatening complication of diabetes mellitus, primarily of TYPE 1 DIABETES MELLITUS with severe INSULIN deficiency and extreme HYPERGLYCEMIA. It is characterized by KETOSIS; DEHYDRATION; and depressed consciousness leading to COMA.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
An enzyme that catalyzes the hydrolysis of sphingomyelin to ceramide (N-acylsphingosine) plus choline phosphate. A defect in this enzyme leads to NIEMANN-PICK DISEASE. EC 3.1.4.12.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
'Ketones' are organic compounds with a specific structure, characterized by a carbonyl group (a carbon double-bonded to an oxygen atom) and two carbon atoms, formed as byproducts when the body breaks down fats for energy due to lack of glucose, often seen in diabetes and starvation states.
The addition of an organic acid radical into a molecule.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
Refers to animals in the period of time just after birth.
A naturally occurring metabolite of HISTIDINE that has antioxidant properties.
Nonionic surfactant mixtures varying in the number of repeating ethoxy (oxy-1,2-ethanediyl) groups. They are used as detergents, emulsifiers, wetting agents, defoaming agents, etc. Octoxynol-9, the compound with 9 repeating ethoxy groups, is a spermatocide.
Any substances taken in by the body that provide nourishment.
Elements of limited time intervals, contributing to particular results or situations.
The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)
Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
BUTYRIC ACID substituted in the beta or 3 position. It is one of the ketone bodies produced in the liver.
Artifactual vesicles formed from the endoplasmic reticulum when cells are disrupted. They are isolated by differential centrifugation and are composed of three structural features: rough vesicles, smooth vesicles, and ribosomes. Numerous enzyme activities are associated with the microsomal fraction. (Glick, Glossary of Biochemistry and Molecular Biology, 1990; from Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
The two lipoprotein layers in the MITOCHONDRION. The outer membrane encloses the entire mitochondrion and contains channels with TRANSPORT PROTEINS to move molecules and ions in and out of the organelle. The inner membrane folds into cristae and contains many ENZYMES important to cell METABOLISM and energy production (MITOCHONDRIAL ATP SYNTHASE).
Intracellular signaling protein kinases that play a signaling role in the regulation of cellular energy metabolism. Their activity largely depends upon the concentration of cellular AMP which is increased under conditions of low energy or metabolic stress. AMP-activated protein kinases modify enzymes involved in LIPID METABOLISM, which in turn provide substrates needed to convert AMP into ATP.
An enzyme that catalyzes the synthesis of hydroxymethylglutaryl-CoA from acetyl-CoA and acetoacetyl-CoA. This is a key enzyme in steroid biosynthesis. This enzyme was formerly listed as EC 4.1.3.5.
A form of encephalopathy with fatty infiltration of the LIVER, characterized by brain EDEMA and VOMITING that may rapidly progress to SEIZURES; COMA; and DEATH. It is caused by a generalized loss of mitochondrial function leading to disturbances in fatty acid and CARNITINE metabolism.
Abstaining from all food.
A primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
The concentration of a compound needed to reduce population growth of organisms, including eukaryotic cells, by 50% in vitro. Though often expressed to denote in vitro antibacterial activity, it is also used as a benchmark for cytotoxicity to eukaryotic cells in culture.
A 51-amino acid pancreatic hormone that plays a major role in the regulation of glucose metabolism, directly by suppressing endogenous glucose production (GLYCOGENOLYSIS; GLUCONEOGENESIS) and indirectly by suppressing GLUCAGON secretion and LIPOLYSIS. Native insulin is a globular protein comprised of a zinc-coordinated hexamer. Each insulin monomer containing two chains, A (21 residues) and B (30 residues), linked by two disulfide bonds. Insulin is used as a drug to control insulin-dependent diabetes mellitus (DIABETES MELLITUS, TYPE 1).
Regular course of eating and drinking adopted by a person or animal.
A thermogenic form of adipose tissue composed of BROWN ADIPOCYTES. It is found in newborns of many species including humans, and in hibernating mammals. Brown fat is richly vascularized, innervated, and densely packed with MITOCHONDRIA which can generate heat directly from the stored lipids.
A 29-amino acid pancreatic peptide derived from proglucagon which is also the precursor of intestinal GLUCAGON-LIKE PEPTIDES. Glucagon is secreted by PANCREATIC ALPHA CELLS and plays an important role in regulation of BLOOD GLUCOSE concentration, ketone metabolism, and several other biochemical and physiological processes. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p1511)
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
A generic term for fats and lipoids, the alcohol-ether-soluble constituents of protoplasm, which are insoluble in water. They comprise the fats, fatty oils, essential oils, waxes, phospholipids, glycolipids, sulfolipids, aminolipids, chromolipids (lipochromes), and fatty acids. (Grant & Hackh's Chemical Dictionary, 5th ed)
Intracellular receptors that can be found in the cytoplasm or in the nucleus. They bind to extracellular signaling molecules that migrate through or are transported across the CELL MEMBRANE. Many members of this class of receptors occur in the cytoplasm and are transported to the CELL NUCLEUS upon ligand-binding where they signal via DNA-binding and transcription regulation. Also included in this category are receptors found on INTRACELLULAR MEMBRANES that act via mechanisms similar to CELL SURFACE RECEPTORS.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
Glucosides are glycosides that contain glucose as the sugar component, often forming part of the plant's defense mechanism and can have various pharmacological effects when extracted and used medically.
Enzymes that catalyze the synthesis of FATTY ACIDS from acetyl-CoA and malonyl-CoA derivatives.
The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.
Transport proteins that carry specific substances in the blood or across cell membranes.
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
Elevated level of AMMONIA in the blood. It is a sign of defective CATABOLISM of AMINO ACIDS or ammonia to UREA.
A family of SERINE ENDOPEPTIDASES isolated from Bacillus subtilis. EC 3.4.21.-
Established cell cultures that have the potential to propagate indefinitely.
Fats present in food, especially in animal products such as meat, meat products, butter, ghee. They are present in lower amounts in nuts, seeds, and avocados.
Techniques to partition various components of the cell into SUBCELLULAR FRACTIONS.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
An essential amino acid that is required for the production of HISTAMINE.
Hydrazines substituted by one or more methyl groups in any position.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
A toxic thiol mercury salt formerly used as a diuretic. It inhibits various biochemical functions, especially in mitochondria, and is used to study those functions.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
Proteins encoded by the mitochondrial genome or proteins encoded by the nuclear genome that are imported to and resident in the MITOCHONDRIA.
Lipid infiltration of the hepatic parenchymal cells resulting in a yellow-colored liver. The abnormal lipid accumulation is usually in the form of TRIGLYCERIDES, either as a single large droplet or multiple small droplets. Fatty liver is caused by an imbalance in the metabolism of FATTY ACIDS.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.
A non-essential amino acid that occurs in high levels in its free state in plasma. It is produced from pyruvate by transamination. It is involved in sugar and acid metabolism, increases IMMUNITY, and provides energy for muscle tissue, BRAIN, and the CENTRAL NERVOUS SYSTEM.

Modification of left ventricular hypertrophy by chronic etomixir treatment. (1/672)

1. Etomoxir (2[6(4-chlorophenoxy)hexyl]oxirane-2-carboxylate), an irreversible carnitine palmitoyl-transferase 1 inhibitor, reduces the expression of the myocardial foetal gene programme and the functional deterioration during heart adaption to a pressure-overload. Etomoxir may, however, also improve the depressed myocardial function of hypertrophied ventricles after a prolonged pressure overload. 2. To test this hypothesis, we administered racemic etomoxir (15 mg kg(-1) day(-1) for 6 weeks) to rats with ascending aortic constriction beginning 6 weeks after imposing the pressure overload. 3. The right ventricular/body weight ratio increased (P<0.05) by 20% in etomoxir treated rats (n = 10) versus untreated rats with ascending aortic constriction (n = 10). Left ventricular weight was increased (P<0.05) by 8%. Etomoxir blunted the increase in left ventricular chamber volume. Etomoxir raised the proportion of V1 isomyosin (35+/-4% versus 24+/-2%; P<0.05) and decreased the percentage of V3 isomyosin (36+/-4% versus 48+/-3%; P<0.05). 4. Maximum isovolumically developed pressure was higher in etomoxir treated rats than in untreated pressure overloaded rats (371+/-22 versus 315+/-23 mmHg; P<0.05). Maximum rates of ventricular pressure development (14,800+/-1310 versus 12,340+/-1030mmHg s(-1); P<0.05) and decline (6440+/-750 versus 5040+/-710 mmHg s(-1); P<0.05) were increased as well. Transformation of pressure values to ventricular wall stress data revealed an improved myocardial function which could partially account for the enhanced function of the whole left ventricle. 5. The co-ordinated action of etomoxir on ventricular mass, geometry and myocardial phenotype enhanced thus the pressure generating capacity of hypertrophied pressure-overloaded left ventricles and delayed the deleterious dilative remodelling.  (+info)

Pharmacokinetic analysis of the cardioprotective effect of 3-(2,2, 2-trimethylhydrazinium) propionate in mice: inhibition of carnitine transport in kidney. (2/672)

The site of action of 3-(2,2,2-trimethylhydrazinium) propionate (THP), a new cardioprotective agent, was investigated in mice and rats. I.p. administration of THP decreased the concentrations of free carnitine and long-chain acylcarnitine in heart tissue. In isolated myocytes, THP inhibited free carnitine transport with a Ki of 1340 microM, which is considerably higher than the observed serum concentration of THP. The major cause of the decreased free carnitine concentration in heart was found to be the decreased serum concentration of free carnitine that resulted from the increased renal clearance of carnitine by THP. The estimated Ki of THP for inhibiting the reabsorption of free carnitine in kidneys was 52.2 microM, which is consistent with the serum THP concentration range. No inhibition of THP on the carnitine palmitoyltransferase activity in isolated mitochondrial fractions was observed. These results indicate that the principal site of action of THP as a cardioprotective agent is the carnitine transport carrier in the kidney, but not the carrier in the heart.  (+info)

A single amino acid change (substitution of glutamate 3 with alanine) in the N-terminal region of rat liver carnitine palmitoyltransferase I abolishes malonyl-CoA inhibition and high affinity binding. (3/672)

We have recently shown by deletion mutation analysis that the conserved first 18 N-terminal amino acid residues of rat liver carnitine palmitoyltransferase I (L-CPTI) are essential for malonyl-CoA inhibition and binding (Shi, J., Zhu, H., Arvidson, D. N. , Cregg, J. M., and Woldegiorgis, G. (1998) Biochemistry 37, 11033-11038). To identify specific residue(s) involved in malonyl-CoA binding and inhibition of L-CPTI, we constructed two more deletion mutants, Delta12 and Delta6, and three substitution mutations within the conserved first six amino acid residues. Mutant L-CPTI, lacking either the first six N-terminal amino acid residues or with a change of glutamic acid 3 to alanine, was expressed at steady-state levels similar to wild type and had near wild type catalytic activity. However, malonyl-CoA inhibition of these mutant enzymes was reduced 100-fold, and high affinity malonyl-CoA binding was lost. A mutant L-CPTI with a change of histidine 5 to alanine caused only partial loss of malonyl-CoA inhibition, whereas a mutant L-CPTI with a change of glutamine 6 to alanine had wild type properties. These results demonstrate that glutamic acid 3 and histidine 5 are necessary for malonyl-CoA binding and inhibition of L-CPTI by malonyl-CoA but are not required for catalysis.  (+info)

Comparisons of flux control exerted by mitochondrial outer-membrane carnitine palmitoyltransferase over ketogenesis in hepatocytes and mitochondria isolated from suckling or adult rats. (4/672)

The primary aim of this paper was to calculate and report flux control coefficients for mitochondrial outer-membrane carnitine palmitoyltransferase (CPT I) over hepatic ketogenesis because its role in controlling this pathway during the neonatal period is of academic importance and immediate clinical relevance. Using hepatocytes isolated from suckling rats as our model system, we measured CPT I activity and carbon flux from palmitate to ketone bodies and to CO2 in the absence and presence of a range of concentrations of etomoxir. (This is converted in situ to etomoxir-CoA which is a specific inhibitor of the enzyme.) From these data we calculated the individual flux control coefficients for CPT I over ketogenesis, CO2 production and total carbon flux (0.51 +/- 0.03; -1.30 +/- 0.26; 0.55 +/- 0.07, respectively) and compared them with equivalent coefficients calculated by similar analyses [Drynan, L., Quant, P.A. & Zammit, V.A. (1996) Biochem. J. 317, 791-795] in hepatocytes isolated from adult rats (0.85 +/- 0.20; 0.23 +/- 0.06; 1.06 +/- 0.29). CPT I exerts significantly less control over ketogenesis in hepatocytes isolated from suckling rats than those from adult rats. In the suckling systems the flux control coefficients for CPT I over ketogenesis specifically and over total carbon flux (< 0.6) are not consistent with the enzyme being rate-limiting. Broadly similar results were obtained and conclusions drawn by reanalysis of previous data {from experiments in mitochondria isolated from suckling or adult rats [Krauss, S., Lascelles, C.V., Zammit, V.A. & Quant, P.A. (1996) Biochem. J. 319, 427-433]} using a different approach of control analysis, although it is not strictly valid to compare flux control coefficients from different systems. Our overall conclusion is that flux control coefficients for CPT I over oxidative fluxes from palmitate (or palmitoyl-CoA) differ markedly according to (a) the metabolic state, (b) the stage of development, (c) the specific pathway studied and (d) the model system.  (+info)

Evidence that carnitine palmitoyltransferase I (CPT I) is expressed in microsomes and peroxisomes of rat liver. Distinct immunoreactivity of the N-terminal domain of the microsomal protein. (5/672)

Mitochondria, microsomes and peroxisomes all express overt (cytosol-facing) carnitine palmitoyltransferase activity that is inhibitable by malonyl-CoA. The overt carnitine palmitoyltransferase activity (CPTo) associated with the different fractions was measured. Mitochondria accounted for 65% of total cellular CPTo activity, with the microsomal and peroxisomal contributions accounting for the remaining 25% and 10%, respectively. In parallel experiments, rat livers were perfused in situ with medium containing dinitrophenyl (DNP)-etomoxir in order to inhibit quantitatively and label covalently (with DNP-etomoxiryl-CoA) the molecular species responsible for CPTo activity in each of the membrane systems under near-physiological conditions. In all three membrane fractions, a single protein with an identical molecular mass of approximately 88,000 kDa (p88) was labelled after DNP-etomoxir perfusion of the liver. The abundance of labelled p88 was quantitatively related to the respective specific activities of CPTo in each fraction. On Western blots the same protein was immunoreactive with three anti-peptide antibodies raised against linear epitopes of the cytosolic N- and C-domains and of the inter-membrane space loop (L) domain of the mitochondrial enzyme (L-CPT I). However, the reaction of the microsomal protein with the anti-N peptide antibody (raised against epitope Val-14-Lys-29 of CPT I) was an order of magnitude stronger than expected from either microsomal CPTo activity or its DNP-etomoxiryl-CoA labelling. This suggests that the N-terminal domain of the microsomal protein differs from that in the mitochondrial or peroxisomal protein. This conclusion was confirmed using antibody back-titration experiments, in which the binding of anti-N and anti-C antibodies by mitochondria and microsomes was quantified.  (+info)

Expression of the rat liver carnitine palmitoyltransferase I (CPT-Ialpha) gene is regulated by Sp1 and nuclear factor Y: chromosomal localization and promoter characterization. (6/672)

Carnitine palmitoyltransferase (CPT)-I catalyses the transfer of long-chain fatty acids from CoA to carnitine for translocation across the mitochondrial inner membrane. Expression of the 'liver' isoform of the CPT-I gene (CPT-Ialpha) is subject to developmental, hormonal and tissue-specific regulation. To understand the basis for control of CPT-Ialpha gene expression, we have characterized the proximal promoter of the CPT-Ialpha gene. Here, we report the sequence of 6839 base pairs of the promoter and the localization of the rat CPT-Ialpha gene to region q43 on chromosome 1. Our studies show that the first 200 base pairs of the promoter are sufficient to drive transcription of the CPT-Ialpha gene. Within this region are two sites that bind both Sp1 and Sp3 transcription factors. In addition, nuclear factor Y (NF-Y) binds the proximal promoter. Mutation at the Sp1 or NF-Y sites severely decreases transcription from the CPT-Ialpha promoter. Other protein binding sites were identified within the first 200 base pairs of the promoter by DNase I footprinting, and these elements contribute to CPT-Ialpha gene expression. Our studies demonstrate that CPT-Ialpha is a TATA-less gene which utilizes NF-Y and Sp proteins to drive basal expression.  (+info)

Peroxisome proliferator-activated receptor alpha mediates the adaptive response to fasting. (7/672)

Prolonged deprivation of food induces dramatic changes in mammalian metabolism, including the release of large amounts of fatty acids from the adipose tissue, followed by their oxidation in the liver. The nuclear receptor known as peroxisome proliferator-activated receptor alpha (PPARalpha) was found to play a role in regulating mitochondrial and peroxisomal fatty acid oxidation, suggesting that PPARalpha may be involved in the transcriptional response to fasting. To investigate this possibility, PPARalpha-null mice were subjected to a high fat diet or to fasting, and their responses were compared with those of wild-type mice. PPARalpha-null mice chronically fed a high fat diet showed a massive accumulation of lipid in their livers. A similar phenotype was noted in PPARalpha-null mice fasted for 24 hours, who also displayed severe hypoglycemia, hypoketonemia, hypothermia, and elevated plasma free fatty acid levels, indicating a dramatic inhibition of fatty acid uptake and oxidation. It is shown that to accommodate the increased requirement for hepatic fatty acid oxidation, PPARalpha mRNA is induced during fasting in wild-type mice. The data indicate that PPARalpha plays a pivotal role in the management of energy stores during fasting. By modulating gene expression, PPARalpha stimulates hepatic fatty acid oxidation to supply substrates that can be metabolized by other tissues.  (+info)

Elevated body fat in rats by the dietary nitric oxide synthase inhibitor, L-N omega nitroarginine. (8/672)

The influence of the dietary nitric oxide (NO) synthase inhibitor, L-N omega nitroarginine (L-NNA) on body fat was examined in rats. In experiment 1, all rats were fed with the same amount of diet with or without 0.02% L-NNA for 8 wk. L-NNA intake caused elevations in serum triglyceride and body fat, and reduction in serum nitrate (a metabolite of nitric oxide). The activity of hepatic carnitine palmitoyltransferase was reduced by L-NNA. In experiment 2, rats were fed for 8 wk with the same amount of diets with or without 0.02% L-NNA supplemented or not with 4% L-arginine. The elevation in body fat, and the reductions in serum nitrate and in the activity of hepatic carnitine palmitoyltransferase by L-NNA were all suppressed by supplemental L-arginine. The results suggest that lower NO generation elevated not only serum triglyceride, but also body fat by reduced fatty acid oxidation.  (+info)

Carnitine is a naturally occurring substance in the body that plays a crucial role in energy production. It transports long-chain fatty acids into the mitochondria, where they can be broken down to produce energy. Carnitine is also available as a dietary supplement and is often used to treat or prevent carnitine deficiency.

The medical definition of Carnitine is:

"A quaternary ammonium compound that occurs naturally in animal tissues, especially in muscle, heart, brain, and liver. It is essential for the transport of long-chain fatty acids into the mitochondria, where they can be oxidized to produce energy. Carnitine also functions as an antioxidant and has been studied as a potential treatment for various conditions, including heart disease, diabetes, and kidney disease."

Carnitine is also known as L-carnitine or levocarnitine. It can be found in foods such as red meat, dairy products, fish, poultry, and tempeh. In the body, carnitine is synthesized from the amino acids lysine and methionine with the help of vitamin C and iron. Some people may have a deficiency in carnitine due to genetic factors, malnutrition, or certain medical conditions, such as kidney disease or liver disease. In these cases, supplementation may be necessary to prevent or treat symptoms of carnitine deficiency.

Carnitine O-palmitoyltransferase (CPT) is an enzyme that plays a crucial role in the transport of long-chain fatty acids into the mitochondrial matrix, where they undergo beta-oxidation to produce energy. There are two main forms of this enzyme: CPT1 and CPT2.

CPT1 is located on the outer mitochondrial membrane and catalyzes the transfer of a long-chain fatty acyl group from coenzyme A (CoA) to carnitine, forming acylcarnitine. This reaction is reversible and allows for the regulation of fatty acid oxidation in response to changes in energy demand.

CPT2 is located on the inner mitochondrial membrane and catalyzes the reverse reaction, transferring the long-chain fatty acyl group from carnitine back to CoA, allowing for the entry of the fatty acid into the beta-oxidation pathway.

Deficiencies in CPT1 or CPT2 can lead to serious metabolic disorders, such as carnitine deficiency and mitochondrial myopathies, which can cause muscle weakness, cardiomyopathy, and other symptoms. Treatment may involve dietary modifications, supplementation with carnitine or medium-chain fatty acids, and in some cases, enzyme replacement therapy.

Serine C-palmitoyltransferase (SCPT) is an enzyme responsible for the rate-limiting step in the biosynthesis of sphingolipids, a type of lipid found in cell membranes. Sphingolipids play crucial roles in signal transduction and cell regulation. The enzyme catalyzes the condensation of serine and palmitoyl-CoA to form 3-ketosphinganine, which is then reduced to sphinganine and further modified to produce various sphingolipids. There are two main forms of SCPT, known as SCPT1 and SCPT2, which differ in their subcellular localization and substrate specificity. Defects in the genes encoding these enzymes can lead to serious inherited disorders affecting multiple organ systems, such as hereditary sensory neuropathy type 1 (HSAN1) and forms of ichthyosis.

Malonyl Coenzyme A (CoA) is not a medical term per se, but rather a biochemical concept. Here's the scientific or biochemical definition:

Malonyl Coenzyme A is an important intermediate in various metabolic pathways, particularly in fatty acid synthesis. It is formed through the reaction between malonic acid and coenzyme A, catalyzed by the enzyme acetyl-CoA carboxylase. Malonyl CoA plays a crucial role in the elongation step of fatty acid synthesis, where it provides the two-carbon unit that is added to a growing fatty acid chain.

In a medical context, understanding the function and regulation of Malonyl CoA metabolism can be relevant for several pathological conditions, including metabolic disorders like diabetes and obesity.

Palmitoyl Coenzyme A, often abbreviated as Palmitoyl-CoA, is a type of fatty acyl coenzyme A that plays a crucial role in the body's metabolism. It is formed from the esterification of palmitic acid (a saturated fatty acid) with coenzyme A.

Medical Definition: Palmitoyl Coenzyme A is a fatty acyl coenzyme A ester, where palmitic acid is linked to coenzyme A via an ester bond. It serves as an important intermediate in lipid metabolism and energy production, particularly through the process of beta-oxidation in the mitochondria. Palmitoyl CoA also plays a role in protein modification, known as S-palmitoylation, which can affect protein localization, stability, and function.

Acyltransferases are a group of enzymes that catalyze the transfer of an acyl group (a functional group consisting of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydrogen atom) from one molecule to another. This transfer involves the formation of an ester bond between the acyl group donor and the acyl group acceptor.

Acyltransferases play important roles in various biological processes, including the biosynthesis of lipids, fatty acids, and other metabolites. They are also involved in the detoxification of xenobiotics (foreign substances) by catalyzing the addition of an acyl group to these compounds, making them more water-soluble and easier to excrete from the body.

Examples of acyltransferases include serine palmitoyltransferase, which is involved in the biosynthesis of sphingolipids, and cholesteryl ester transfer protein (CETP), which facilitates the transfer of cholesteryl esters between lipoproteins.

Acyltransferases are classified based on the type of acyl group they transfer and the nature of the acyl group donor and acceptor molecules. They can be further categorized into subclasses based on their sequence similarities, three-dimensional structures, and evolutionary relationships.

Carnitine acyltransferases are a group of enzymes that play a crucial role in the transport and metabolism of fatty acids within cells. These enzymes are responsible for transferring acyl groups from acyl-CoAs to carnitine, forming acylcarnitines, which can then be transported across the mitochondrial membrane and into the mitochondrial matrix.

Once inside the matrix, the acyl groups can be released from carnitine and oxidized in the beta-oxidation pathway to produce energy in the form of ATP. There are three main types of carnitine acyltransferases: Carnitine palmitoyltransferase I (CPT I), located on the outer mitochondrial membrane, which activates long-chain fatty acids for transport into the mitochondria; Carnitine palmitoyltransferase II (CPT II), located on the inner mitochondrial membrane, which reconverts acylcarnitines back to acyl-CoAs for oxidation; and carnitine octanoyltransferase (CRAT), which is involved in the metabolism of medium-chain fatty acids.

Deficiencies in these enzymes can lead to various metabolic disorders, such as CPT II deficiency, which can cause muscle weakness, hypoglycemia, and cardiomyopathy. Proper regulation of carnitine acyltransferases is essential for maintaining healthy fatty acid metabolism and overall cellular function.

Carnitine O-acetyltransferase (COAT) is an enzyme that plays a crucial role in the transport and metabolism of fatty acids within cells. It is also known as carnitine palmitoyltransferase I (CPT I).

The primary function of COAT is to catalyze the transfer of an acetyl group from acetyl-CoA to carnitine, forming acetylcarnitine and free CoA. This reaction is essential for the entry of long-chain fatty acids into the mitochondrial matrix, where they undergo beta-oxidation to produce energy in the form of ATP.

COAT is located on the outer membrane of the mitochondria and functions as a rate-limiting enzyme in fatty acid oxidation. Its activity can be inhibited by malonyl-CoA, which is an intermediate in fatty acid synthesis. This inhibition helps regulate the balance between fatty acid oxidation and synthesis, ensuring that cells have enough energy while preventing excessive accumulation of lipids.

Deficiencies or mutations in COAT can lead to various metabolic disorders, such as carnitine palmitoyltransferase I deficiency (CPT I deficiency), which may cause symptoms like muscle weakness, hypoglycemia, and cardiomyopathy. Proper diagnosis and management of these conditions often involve dietary modifications, supplementation with carnitine, and avoidance of fasting to prevent metabolic crises.

Acyl Coenzyme A (often abbreviated as Acetyl-CoA or Acyl-CoA) is a crucial molecule in metabolism, particularly in the breakdown and oxidation of fats and carbohydrates to produce energy. It is a thioester compound that consists of a fatty acid or an acetate group linked to coenzyme A through a sulfur atom.

Acyl CoA plays a central role in several metabolic pathways, including:

1. The citric acid cycle (Krebs cycle): In the mitochondria, Acyl-CoA is formed from the oxidation of fatty acids or the breakdown of certain amino acids. This Acyl-CoA then enters the citric acid cycle to produce high-energy electrons, which are used in the electron transport chain to generate ATP (adenosine triphosphate), the main energy currency of the cell.
2. Beta-oxidation: The breakdown of fatty acids occurs in the mitochondria through a process called beta-oxidation, where Acyl-CoA is sequentially broken down into smaller units, releasing acetyl-CoA, which then enters the citric acid cycle.
3. Ketogenesis: In times of low carbohydrate availability or during prolonged fasting, the liver can produce ketone bodies from acetyl-CoA to supply energy to other organs, such as the brain and heart.
4. Protein synthesis: Acyl-CoA is also involved in the modification of proteins by attaching fatty acid chains to them (a process called acetylation), which can influence protein function and stability.

In summary, Acyl Coenzyme A is a vital molecule in metabolism that connects various pathways related to energy production, fatty acid breakdown, and protein modification.

I'd be happy to help! However, I believe there might be a slight misunderstanding in your question. Mitochondria are organelles found in the cells of all complex living organisms, including humans, while the liver is a large, solid organ located in the upper right portion of the abdomen. They don't have a medical definition together. I can certainly provide you with separate definitions for each:

1. Mitochondria: These are double-membrane-bound cellular organelles that generate most of the chemical energy needed to power the cell's biochemical reactions. Commonly known as the "powerhouse of the cell," mitochondria convert organic substrates, such as glucose, fatty acids, and amino acids, into adenosine triphosphate (ATP) through a process called oxidative phosphorylation. Mitochondria are dynamic structures that can change their shape, size, and number through fission (division) and fusion (merging) processes. They play essential roles in various cellular functions, including calcium signaling, apoptosis (programmed cell death), and the regulation of cellular metabolism.

2. Liver: The liver is a large, lobulated organ that lies mainly in the upper right portion of the abdominal cavity, just below the diaphragm. It plays a crucial role in various physiological functions, such as detoxification, protein synthesis, metabolism, and nutrient storage. The liver is responsible for removing toxins from the bloodstream, producing bile to aid in digestion, regulating glucose levels, synthesizing plasma proteins, and storing glycogen, vitamins, and minerals. It also contributes to the metabolism of carbohydrates, lipids, and amino acids, helping maintain energy homeostasis in the body.

I hope this clarifies any confusion! If you have any further questions or need more information, please don't hesitate to ask.

Palmitoylcarnitine is a type of acylcarnitine, which is an ester formed from carnitine and a fatty acid. Specifically, palmitoylcarnitine consists of the long-chain fatty acid palmitate (a 16-carbon saturated fatty acid) linked to carnitine through an ester bond.

In the human body, palmitoylcarnitine plays a crucial role in the transport and metabolism of long-chain fatty acids within mitochondria, the energy-producing organelles found in cells. The process involves converting palmitate into palmitoylcarnitine by an enzyme called carnitine palmitoyltransferase I (CPT-I) in the outer mitochondrial membrane. Palmitoylcarnitine is then transported across the inner mitochondrial membrane via a specific transporter, where it is converted back to palmitate by another enzyme called carnitine palmitoyltransferase II (CPT-II). The palmitate can then undergo beta-oxidation, a process that generates energy in the form of ATP.

Abnormal levels of palmitoylcarnitine in blood or other bodily fluids may indicate an underlying metabolic disorder, such as defects in fatty acid oxidation or carnitine transport. These conditions can lead to various symptoms, including muscle weakness, cardiomyopathy, and developmental delays.

Sphingolipids are a class of lipids that contain a sphingosine base, which is a long-chain amino alcohol with an unsaturated bond and an amino group. They are important components of animal cell membranes, particularly in the nervous system. Sphingolipids include ceramides, sphingomyelins, and glycosphingolipids.

Ceramides consist of a sphingosine base linked to a fatty acid through an amide bond. They play important roles in cell signaling, membrane structure, and apoptosis (programmed cell death).

Sphingomyelins are formed when ceramides combine with phosphorylcholine, resulting in the formation of a polar head group. Sphingomyelins are major components of the myelin sheath that surrounds nerve cells and are involved in signal transduction and membrane structure.

Glycosphingolipids contain one or more sugar residues attached to the ceramide backbone, forming complex structures that play important roles in cell recognition, adhesion, and signaling. Abnormalities in sphingolipid metabolism have been linked to various diseases, including neurological disorders, cancer, and cardiovascular disease.

Epoxy compounds, also known as epoxy resins, are a type of thermosetting polymer characterized by the presence of epoxide groups in their molecular structure. An epoxide group is a chemical functional group consisting of an oxygen atom double-bonded to a carbon atom, which is itself bonded to another carbon atom.

Epoxy compounds are typically produced by reacting a mixture of epichlorohydrin and bisphenol-A or other similar chemicals under specific conditions. The resulting product is a two-part system consisting of a resin and a hardener, which must be mixed together before use.

Once the two parts are combined, a chemical reaction takes place that causes the mixture to cure or harden into a solid material. This curing process can be accelerated by heat, and once fully cured, epoxy compounds form a strong, durable, and chemically resistant material that is widely used in various industrial and commercial applications.

In the medical field, epoxy compounds are sometimes used as dental restorative materials or as adhesives for bonding medical devices or prosthetics. However, it's important to note that some people may have allergic reactions to certain components of epoxy compounds, so their use must be carefully evaluated and monitored in a medical context.

Acetyl-L-carnitine, also known as ALCAR, is a form of the amino acid carnitine. It is a naturally occurring substance in the body that plays a crucial role in energy production in cells, particularly within mitochondria, the "powerhouses" of the cell.

Acetyl-L-carnitine is involved in the transport of fatty acids into the mitochondria, where they can be broken down to produce energy. It also functions as an antioxidant, helping to protect cells from damage caused by free radicals.

This compound has been studied for its potential benefits in various medical conditions, including neurological disorders, cardiovascular diseases, and liver diseases. Some research suggests that Acetyl-L-carnitine may help improve cognitive function, reduce fatigue, and alleviate pain. However, more studies are needed to confirm these findings and establish the optimal dosage and safety profiles for different medical conditions.

It is important to note that while Acetyl-L-carnitine is available as a dietary supplement, its use should be discussed with a healthcare provider before starting any new supplement regimen, especially if you have a medical condition or are taking medication.

Hereditary Sensory and Autonomic Neuropathies (HSANs) are a group of inherited disorders that affect the sensory and autonomic nerves. These nerves are responsible for transmitting information about senses such as touch, pain, temperature, and vibration to the brain, as well as controlling automatic functions like blood pressure, heart rate, and digestion.

HSANs are caused by genetic mutations that result in damage to the peripheral nerves. There are several types of HSANs, each with its own specific symptoms and patterns of inheritance. Some common features include:

* Loss of sensation in the hands and feet
* Pain insensitivity
* Absent or reduced reflexes
* Autonomic dysfunction, such as abnormal sweating, blood pressure regulation, and digestive problems

The severity and progression of HSANs can vary widely depending on the specific type and individual factors. Treatment is generally focused on managing symptoms and preventing complications, such as injuries from lack of pain sensation or falls due to balance problems. Early diagnosis and intervention are important for optimizing outcomes.

Fatty acids are carboxylic acids with a long aliphatic chain, which are important components of lipids and are widely distributed in living organisms. They can be classified based on the length of their carbon chain, saturation level (presence or absence of double bonds), and other structural features.

The two main types of fatty acids are:

1. Saturated fatty acids: These have no double bonds in their carbon chain and are typically solid at room temperature. Examples include palmitic acid (C16:0) and stearic acid (C18:0).
2. Unsaturated fatty acids: These contain one or more double bonds in their carbon chain and can be further classified into monounsaturated (one double bond) and polyunsaturated (two or more double bonds) fatty acids. Examples of unsaturated fatty acids include oleic acid (C18:1, monounsaturated), linoleic acid (C18:2, polyunsaturated), and alpha-linolenic acid (C18:3, polyunsaturated).

Fatty acids play crucial roles in various biological processes, such as energy storage, membrane structure, and cell signaling. Some essential fatty acids cannot be synthesized by the human body and must be obtained through dietary sources.

"Palmitates" are salts or esters of palmitic acid, a saturated fatty acid that is commonly found in animals and plants. Palmitates can be found in various substances, including cosmetics, food additives, and medications. For example, sodium palmitate is a common ingredient in soaps and detergents, while retinyl palmitate is a form of vitamin A used in skin care products and dietary supplements.

In a medical context, "palmitates" may be mentioned in the results of laboratory tests that measure lipid metabolism or in discussions of nutrition and dietary fats. However, it is important to note that "palmitates" themselves are not typically a focus of medical diagnosis or treatment, but rather serve as components of various substances that may have medical relevance.

Starvation is a severe form of malnutrition, characterized by insufficient intake of calories and nutrients to meet the body's energy requirements. This leads to a catabolic state where the body begins to break down its own tissues for energy, resulting in significant weight loss, muscle wasting, and weakness. Prolonged starvation can also lead to serious medical complications such as organ failure, electrolyte imbalances, and even death. It is typically caused by a lack of access to food due to poverty, famine, or other social or economic factors, but can also be a result of severe eating disorders such as anorexia nervosa.

Ketone bodies, also known as ketones or ketoacids, are organic compounds that are produced by the liver during the metabolism of fats when carbohydrate intake is low. They include acetoacetate (AcAc), beta-hydroxybutyrate (BHB), and acetone. These molecules serve as an alternative energy source for the body, particularly for the brain and heart, when glucose levels are insufficient to meet energy demands.

In a healthy individual, ketone bodies are present in low concentrations; however, during periods of fasting, starvation, or intense physical exertion, ketone production increases significantly. In some pathological conditions like uncontrolled diabetes mellitus, the body may produce excessive amounts of ketones, leading to a dangerous metabolic state called diabetic ketoacidosis (DKA).

Elevated levels of ketone bodies can be detected in blood or urine and are often used as an indicator of metabolic status. Monitoring ketone levels is essential for managing certain medical conditions, such as diabetes, where maintaining optimal ketone concentrations is crucial to prevent complications.

The liver is a large, solid organ located in the upper right portion of the abdomen, beneath the diaphragm and above the stomach. It plays a vital role in several bodily functions, including:

1. Metabolism: The liver helps to metabolize carbohydrates, fats, and proteins from the food we eat into energy and nutrients that our bodies can use.
2. Detoxification: The liver detoxifies harmful substances in the body by breaking them down into less toxic forms or excreting them through bile.
3. Synthesis: The liver synthesizes important proteins, such as albumin and clotting factors, that are necessary for proper bodily function.
4. Storage: The liver stores glucose, vitamins, and minerals that can be released when the body needs them.
5. Bile production: The liver produces bile, a digestive juice that helps to break down fats in the small intestine.
6. Immune function: The liver plays a role in the immune system by filtering out bacteria and other harmful substances from the blood.

Overall, the liver is an essential organ that plays a critical role in maintaining overall health and well-being.

Coenzyme A, often abbreviated as CoA or sometimes holo-CoA, is a coenzyme that plays a crucial role in several important chemical reactions in the body, particularly in the metabolism of carbohydrates, fatty acids, and amino acids. It is composed of a pantothenic acid (vitamin B5) derivative called pantothenate, an adenosine diphosphate (ADP) molecule, and a terminal phosphate group.

Coenzyme A functions as a carrier molecule for acetyl groups, which are formed during the breakdown of carbohydrates, fatty acids, and some amino acids. The acetyl group is attached to the sulfur atom in CoA, forming acetyl-CoA, which can then be used as a building block for various biochemical pathways, such as the citric acid cycle (Krebs cycle) and fatty acid synthesis.

In summary, Coenzyme A is a vital coenzyme that helps facilitate essential metabolic processes by carrying and transferring acetyl groups in the body.

Palmitic acid is a type of saturated fatty acid, which is a common component in many foods and also produced naturally by the human body. Its chemical formula is C16H32O2. It's named after palm trees because it was first isolated from palm oil, although it can also be found in other vegetable oils, animal fats, and dairy products.

In the human body, palmitic acid plays a role in energy production and storage. However, consuming large amounts of this fatty acid has been linked to an increased risk of heart disease due to its association with elevated levels of bad cholesterol (LDL). The World Health Organization recommends limiting the consumption of saturated fats, including palmitic acid, to less than 10% of total energy intake.

Oxidation-Reduction (redox) reactions are a type of chemical reaction involving a transfer of electrons between two species. The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced. Oxidation and reduction always occur together in a redox reaction, hence the term "oxidation-reduction."

In biological systems, redox reactions play a crucial role in many cellular processes, including energy production, metabolism, and signaling. The transfer of electrons in these reactions is often facilitated by specialized molecules called electron carriers, such as nicotinamide adenine dinucleotide (NAD+/NADH) and flavin adenine dinucleotide (FAD/FADH2).

The oxidation state of an element in a compound is a measure of the number of electrons that have been gained or lost relative to its neutral state. In redox reactions, the oxidation state of one or more elements changes as they gain or lose electrons. The substance that is oxidized has a higher oxidation state, while the substance that is reduced has a lower oxidation state.

Overall, oxidation-reduction reactions are fundamental to the functioning of living organisms and are involved in many important biological processes.

Gamma-Butyrobetaine Dioxygenase (GBD, or also known as ETHE1) is an enzyme that catalyzes the conversion of gamma-butyrobetaine to succinate and hydrogen peroxide in the final step of L-carnitine biosynthesis. This mitochondrial matrix enzyme requires iron (Fe2+) as a cofactor for its activity. Deficiency or mutations in this enzyme can lead to a rare genetic disorder called "ethylmalonic aciduria and combined oxidative phosphorylation deficiency type 6" (ETHE1), which is characterized by the accumulation of ethylmalonic acid, gamma-butyrobetaine, and other organic acids in body fluids.

"Inbred strains of rats" are genetically identical rodents that have been produced through many generations of brother-sister mating. This results in a high degree of homozygosity, where the genes at any particular locus in the genome are identical in all members of the strain.

Inbred strains of rats are widely used in biomedical research because they provide a consistent and reproducible genetic background for studying various biological phenomena, including the effects of drugs, environmental factors, and genetic mutations on health and disease. Additionally, inbred strains can be used to create genetically modified models of human diseases by introducing specific mutations into their genomes.

Some commonly used inbred strains of rats include the Wistar Kyoto (WKY), Sprague-Dawley (SD), and Fischer 344 (F344) rat strains. Each strain has its own unique genetic characteristics, making them suitable for different types of research.

Organic cation transport proteins (OCTs) are a group of membrane transporters that facilitate the movement of organic cations across biological membranes. These transporters play an essential role in the absorption, distribution, and elimination of various endogenous and exogenous substances, including drugs and toxins.

There are four main types of OCTs, namely OCT1, OCT2, OCT3, and OCTN1 (also known as novel organic cation transporter 1 or OCT6). These proteins belong to the solute carrier (SLC) family, specifically SLC22A.

OCTs have a broad substrate specificity and can transport various organic cations, such as neurotransmitters (e.g., serotonin, dopamine, histamine), endogenous compounds (e.g., creatinine, choline), and drugs (e.g., metformin, quinidine, morphine). The transport process is typically sodium-independent and can occur in both directions, depending on the concentration gradient of the substrate.

OCTs are widely expressed in various tissues, including the liver, kidney, intestine, brain, heart, and placenta. Their expression patterns and functions vary among different OCT types, contributing to their diverse roles in physiology and pharmacology. Dysfunction of OCTs has been implicated in several diseases, such as drug toxicity, neurodegenerative disorders, and cancer.

In summary, organic cation transport proteins are membrane transporters that facilitate the movement of organic cations across biological membranes, playing crucial roles in the absorption, distribution, and elimination of various substances, including drugs and toxins.

Submitochondrial particles, also known as "submitochondrial vesicles" or "inner membrane fragments," are small particles that consist of the inner mitochondrial membrane and the associated components. They are obtained through sonication or other methods of disrupting mitochondria, which results in breaking down the outer membrane while leaving the inner membrane intact. These particles can be used in various biochemical studies to investigate the structure, function, and composition of the inner mitochondrial membrane and its components, such as the electron transport chain and ATP synthase complexes.

Myoglobinuria is a medical condition characterized by the presence of myoglobin in the urine. Myoglobin is a protein found in muscle cells that is released into the bloodstream when muscle tissue is damaged or broken down, such as during intense exercise, trauma, or muscle diseases like muscular dystrophy and rhabdomyolysis.

When myoglobin is present in high concentrations in the blood, it can damage the kidneys by causing direct tubular injury, cast formation, and obstruction, which can lead to acute kidney injury (AKI) or even renal failure if left untreated. Symptoms of myoglobinuria may include dark-colored urine, muscle pain, weakness, and swelling, as well as symptoms related to AKI such as nausea, vomiting, and decreased urine output.

Diagnosis of myoglobinuria is typically made by detecting myoglobin in the urine using a dipstick test or more specific tests like immunoassays or mass spectrometry. Treatment may involve aggressive fluid resuscitation, alkalization of the urine to prevent myoglobin precipitation, and management of any underlying conditions causing muscle damage.

Inborn errors of lipid metabolism refer to genetic disorders that affect the body's ability to break down and process lipids (fats) properly. These disorders are caused by defects in genes that code for enzymes or proteins involved in lipid metabolism. As a result, toxic levels of lipids or their intermediates may accumulate in the body, leading to various health issues, which can include neurological problems, liver dysfunction, muscle weakness, and cardiovascular disease.

There are several types of inborn errors of lipid metabolism, including:

1. Disorders of fatty acid oxidation: These disorders affect the body's ability to convert long-chain fatty acids into energy, leading to muscle weakness, hypoglycemia, and cardiomyopathy. Examples include medium-chain acyl-CoA dehydrogenase deficiency (MCAD) and very long-chain acyl-CoA dehydrogenase deficiency (VLCAD).
2. Disorders of cholesterol metabolism: These disorders affect the body's ability to process cholesterol, leading to an accumulation of cholesterol or its intermediates in various tissues. Examples include Smith-Lemli-Opitz syndrome and lathosterolosis.
3. Disorders of sphingolipid metabolism: These disorders affect the body's ability to break down sphingolipids, leading to an accumulation of these lipids in various tissues. Examples include Gaucher disease, Niemann-Pick disease, and Fabry disease.
4. Disorders of glycerophospholipid metabolism: These disorders affect the body's ability to break down glycerophospholipids, leading to an accumulation of these lipids in various tissues. Examples include rhizomelic chondrodysplasia punctata and abetalipoproteinemia.

Inborn errors of lipid metabolism are typically diagnosed through genetic testing and biochemical tests that measure the activity of specific enzymes or the levels of specific lipids in the body. Treatment may include dietary modifications, supplements, enzyme replacement therapy, or gene therapy, depending on the specific disorder and its severity.

Palmitic acid is a type of saturated fatty acid, which is a common component in many foods and also produced by the body. Its chemical formula is C16:0, indicating that it contains 16 carbon atoms and no double bonds. Palmitic acid is found in high concentrations in animal fats, such as butter, lard, and beef tallow, as well as in some vegetable oils, like palm kernel oil and coconut oil.

In the human body, palmitic acid can be synthesized from other substances or absorbed through the diet. It plays a crucial role in various biological processes, including energy storage, membrane structure formation, and signaling pathways regulation. However, high intake of palmitic acid has been linked to an increased risk of developing cardiovascular diseases due to its potential to raise low-density lipoprotein (LDL) cholesterol levels in the blood.

It is essential to maintain a balanced diet and consume palmitic acid-rich foods in moderation, along with regular exercise and a healthy lifestyle, to reduce the risk of chronic diseases.

Mitochondria in muscle, also known as the "powerhouses" of the cell, are organelles that play a crucial role in generating energy for muscle cells through a process called cellular respiration. They convert the chemical energy found in glucose and oxygen into ATP (adenosine triphosphate), which is the main source of energy used by cells.

Muscle cells contain a high number of mitochondria due to their high energy demands for muscle contraction and relaxation. The number and size of mitochondria in muscle fibers can vary depending on the type of muscle fiber, with slow-twitch, aerobic fibers having more numerous and larger mitochondria than fast-twitch, anaerobic fibers.

Mitochondrial dysfunction has been linked to various muscle disorders, including mitochondrial myopathies, which are characterized by muscle weakness, exercise intolerance, and other symptoms related to impaired energy production in the muscle cells.

Ceramides are a type of lipid molecule that are found naturally in the outer layer of the skin (the stratum corneum). They play a crucial role in maintaining the barrier function and hydration of the skin. Ceramides help to seal in moisture, support the structure of the skin, and protect against environmental stressors such as pollution and bacteria.

In addition to their role in the skin, ceramides have also been studied for their potential therapeutic benefits in various medical conditions. For example, abnormal levels of ceramides have been implicated in several diseases, including diabetes, cardiovascular disease, and cancer. As a result, ceramide-based therapies are being investigated as potential treatments for these conditions.

Medically, ceramides may be mentioned in the context of skin disorders or diseases where there is a disruption in the skin's barrier function, such as eczema, psoriasis, and ichthyosis. In these cases, ceramide-based therapies may be used to help restore the skin's natural barrier and improve its overall health and appearance.

Microbodies are small, membrane-bound organelles found in the cells of eukaryotic organisms. They typically measure between 0.2 to 0.5 micrometers in diameter and play a crucial role in various metabolic processes, particularly in the detoxification of harmful substances and the synthesis of lipids.

There are several types of microbodies, including:

1. Peroxisomes: These are the most common type of microbody. They contain enzymes that help break down fatty acids and amino acids, producing hydrogen peroxide as a byproduct. Another set of enzymes within peroxisomes then converts the harmful hydrogen peroxide into water and oxygen, thus detoxifying the cell.
2. Glyoxysomes: These microbodies are primarily found in plants and some fungi. They contain enzymes involved in the glyoxylate cycle, a metabolic pathway that helps convert stored fats into carbohydrates during germination.
3. Microbody-like particles (MLPs): These are smaller organelles found in certain protists and algae. Their functions are not well understood but are believed to be involved in lipid metabolism.

It is important to note that microbodies do not have a uniform structure or function across all eukaryotic cells, and their specific roles can vary depending on the organism and cell type.

Lipoylation is the post-translational modification of proteins by attaching lipoic acid (also known as α-lipoic acid or octanoic acid) to specific lysine residues in the protein. This process plays a crucial role in mitochondrial energy metabolism, particularly in the functioning of multi-enzyme complexes involved in the citric acid cycle and oxidative phosphorylation.

The lipoic acid cofactor is covalently attached to the target proteins by enzymes called lipoyltransferases. Once attached, lipoic acid can undergo reversible oxidation-reduction reactions, which facilitate the transfer of electrons and acetyl groups during metabolic processes. These redox reactions are essential for the proper functioning of critical mitochondrial enzymes such as pyruvate dehydrogenase complex (PDH), α-ketoglutarate dehydrogenase complex (KGDHC), and branched-chain ketoacid dehydrogenase complex (BCKDC).

Dysregulation of lipoylation has been implicated in various diseases, including neurodegenerative disorders, metabolic conditions, and cancer. Therefore, understanding the molecular mechanisms underlying lipoylation is important for developing potential therapeutic strategies to target these diseases.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Caprylates are the salts or esters of capric acid, a saturated fatty acid with a chain length of 8 carbon atoms. In medical and biological contexts, caprylate refers to the anion (negatively charged ion) form of capric acid, which has the chemical formula C8H17O2-. Caprylates are used in various applications, including as food additives, pharmaceuticals, and personal care products.

Some examples of caprylate compounds include:

* Sodium caprylate (sodium octanoate): a sodium salt commonly used as a preservative and flavor enhancer in foods.
* Calcium caprylate (calcium octanoate): a calcium salt used as an emulsifier in food products and as a stabilizer in cosmetics.
* Caprylic acid/caprylate triglycerides: esters of glycerin with caprylic acid, used as emollients and solvents in skin care products and pharmaceuticals.

Caprylates have antimicrobial properties against certain bacteria, fungi, and viruses, making them useful in various medical applications. For instance, sodium caprylate is sometimes used as an antifungal agent to treat conditions like candidiasis (yeast infections). However, more research is needed to fully understand the potential benefits and risks of using caprylates for medicinal purposes.

I'm happy to help! However, it seems like there are two terms combined into one request: "Mitochondria" and "Heart." I will provide separate definitions for each.

Mitochondrion (singular) or Mitochondria (plural): These are specialized structures found in the cytoplasm of most eukaryotic cells (cells with a true nucleus), including human cells. They are often referred to as the "powerhouse" of the cell because they generate energy in the form of ATP (adenosine triphosphate) through a process called oxidative phosphorylation. Mitochondria contain their own DNA, which is distinct from the nuclear DNA, and are believed to have originated from ancient bacteria that established a symbiotic relationship with primitive eukaryotic cells.

Heart: In human anatomy, the heart is a muscular organ responsible for pumping blood throughout the body. It is located in the thoracic cavity, slightly left of the center, and is enclosed by the pericardium, a double-walled sac that provides protection and lubrication for the heart's movement. The human heart is divided into four chambers: two atria on the top and two ventricles on the bottom. The right side of the heart receives deoxygenated blood from the body and pumps it to the lungs, while the left side receives oxygenated blood from the lungs and pumps it to the rest of the body. The heart's pumping action is regulated by electrical signals that originate in a group of specialized cardiac muscle cells called the sinoatrial node (SA node).

Sphingomonas is a genus of gram-negative, aerobic bacteria that are widely distributed in the environment. They are known for their ability to degrade various organic compounds and are often found in water, soil, and air samples. The cells of Sphingomonas species are typically straight or slightly curved rods, and they do not form spores.

One distinctive feature of Sphingomonas species is the presence of a unique lipid called sphingolipid in their cell membranes. This lipid contains a long-chain base called sphingosine, which is not found in the cell membranes of other gram-negative bacteria. The genus Sphingomonas includes several species that have been associated with human infections, particularly in immunocompromised individuals. These infections can include bacteremia, pneumonia, and urinary tract infections. However, Sphingomonas species are generally considered to be of low virulence and are not typically regarded as major pathogens.

Digitonin is a type of saponin, which is a natural substance found in some plants. It is often used in laboratory settings as a detergent to disrupt cell membranes and make it easier to study the contents of cells. Digitonin specifically binds to cholesterol in cell membranes, making it a useful tool for studying cholesterol-rich structures such as lipid rafts. It is not used as a medication in humans.

Sphingosine N-acyltransferase, also known as serine palmitoyltransferase, is an enzyme that catalyzes the initial and rate-limiting step in de novo sphingolipid synthesis. This enzyme is responsible for transferring an acyl group from acyl-CoA to sphingosine, forming 3-ketosphinganine. The reaction occurs in the endoplasmic reticulum and is the first committed step in the biosynthetic pathway of sphingolipids, which are important components of cell membranes and play crucial roles in various cellular processes such as signal transduction and apoptosis. Defects in this enzyme have been associated with several diseases, including hereditary sensory and autonomic neuropathy type I (HSAN1) and cerebral spinalvascular narrowing.

Intracellular membranes refer to the membrane structures that exist within a eukaryotic cell (excluding bacteria and archaea, which are prokaryotic and do not have intracellular membranes). These membranes compartmentalize the cell, creating distinct organelles or functional regions with specific roles in various cellular processes.

Major types of intracellular membranes include:

1. Nuclear membrane (nuclear envelope): A double-membraned structure that surrounds and protects the genetic material within the nucleus. It consists of an outer and inner membrane, perforated by nuclear pores that regulate the transport of molecules between the nucleus and cytoplasm.
2. Endoplasmic reticulum (ER): An extensive network of interconnected tubules and sacs that serve as a major site for protein folding, modification, and lipid synthesis. The ER has two types: rough ER (with ribosomes on its surface) and smooth ER (without ribosomes).
3. Golgi apparatus/Golgi complex: A series of stacked membrane-bound compartments that process, sort, and modify proteins and lipids before they are transported to their final destinations within the cell or secreted out of the cell.
4. Lysosomes: Membrane-bound organelles containing hydrolytic enzymes for breaking down various biomolecules (proteins, carbohydrates, lipids, and nucleic acids) in the process called autophagy or from outside the cell via endocytosis.
5. Peroxisomes: Single-membrane organelles involved in various metabolic processes, such as fatty acid oxidation and detoxification of harmful substances like hydrogen peroxide.
6. Vacuoles: Membrane-bound compartments that store and transport various molecules, including nutrients, waste products, and enzymes. Plant cells have a large central vacuole for maintaining turgor pressure and storing metabolites.
7. Mitochondria: Double-membraned organelles responsible for generating energy (ATP) through oxidative phosphorylation and other metabolic processes, such as the citric acid cycle and fatty acid synthesis.
8. Chloroplasts: Double-membraned organelles found in plant cells that convert light energy into chemical energy during photosynthesis, producing oxygen and organic compounds (glucose) from carbon dioxide and water.
9. Endoplasmic reticulum (ER): A network of interconnected membrane-bound tubules involved in protein folding, modification, and transport; it is divided into two types: rough ER (with ribosomes on the surface) and smooth ER (without ribosomes).
10. Nucleus: Double-membraned organelle containing genetic material (DNA) and associated proteins involved in replication, transcription, RNA processing, and DNA repair. The nuclear membrane separates the nucleoplasm from the cytoplasm and contains nuclear pores for transporting molecules between the two compartments.

Isoenzymes, also known as isoforms, are multiple forms of an enzyme that catalyze the same chemical reaction but differ in their amino acid sequence, structure, and/or kinetic properties. They are encoded by different genes or alternative splicing of the same gene. Isoenzymes can be found in various tissues and organs, and they play a crucial role in biological processes such as metabolism, detoxification, and cell signaling. Measurement of isoenzyme levels in body fluids (such as blood) can provide valuable diagnostic information for certain medical conditions, including tissue damage, inflammation, and various diseases.

Lipid metabolism is the process by which the body breaks down and utilizes lipids (fats) for various functions, such as energy production, cell membrane formation, and hormone synthesis. This complex process involves several enzymes and pathways that regulate the digestion, absorption, transport, storage, and consumption of fats in the body.

The main types of lipids involved in metabolism include triglycerides, cholesterol, phospholipids, and fatty acids. The breakdown of these lipids begins in the digestive system, where enzymes called lipases break down dietary fats into smaller molecules called fatty acids and glycerol. These molecules are then absorbed into the bloodstream and transported to the liver, which is the main site of lipid metabolism.

In the liver, fatty acids may be further broken down for energy production or used to synthesize new lipids. Excess fatty acids may be stored as triglycerides in specialized cells called adipocytes (fat cells) for later use. Cholesterol is also metabolized in the liver, where it may be used to synthesize bile acids, steroid hormones, and other important molecules.

Disorders of lipid metabolism can lead to a range of health problems, including obesity, diabetes, cardiovascular disease, and non-alcoholic fatty liver disease (NAFLD). These conditions may be caused by genetic factors, lifestyle habits, or a combination of both. Proper diagnosis and management of lipid metabolism disorders typically involves a combination of dietary changes, exercise, and medication.

Escherichia coli (E. coli) O157 is a serotype of the bacterium E. coli that is associated with foodborne illness. This strain is pathogenic and produces Shiga toxins, which can cause severe damage to the lining of the small intestine and potentially lead to hemorrhagic diarrhea and kidney failure. E. coli O157 is often transmitted through contaminated food, particularly undercooked ground beef, as well as raw or unpasteurized dairy products, fruits, and vegetables. It can also be spread through contact with infected individuals or animals, especially in settings like farms, petting zoos, and swimming pools. Proper food handling, cooking, and hygiene practices are crucial to preventing E. coli O157 infections.

Sphingosine is not a medical term per se, but rather a biological compound with importance in the field of medicine. It is a type of sphingolipid, a class of lipids that are crucial components of cell membranes. Sphingosine itself is a secondary alcohol with an amino group and two long-chain hydrocarbons.

Medically, sphingosine is significant due to its role as a precursor in the synthesis of other sphingolipids, such as ceramides, sphingomyelins, and gangliosides, which are involved in various cellular processes like signal transduction, cell growth, differentiation, and apoptosis (programmed cell death).

Moreover, sphingosine-1-phosphate (S1P), a derivative of sphingosine, is an important bioactive lipid mediator that regulates various physiological functions, including immune response, vascular maturation, and neuronal development. Dysregulation of S1P signaling has been implicated in several diseases, such as cancer, inflammation, and cardiovascular disorders.

In summary, sphingosine is a crucial biological compound with medical relevance due to its role as a precursor for various sphingolipids involved in cellular processes and as a precursor for the bioactive lipid mediator S1P.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Betaine, also known as trimethylglycine, is a naturally occurring compound that can be found in various foods such as beets, spinach, and whole grains. In the body, betaine functions as an osmolyte, helping to regulate water balance in cells, and as a methyl donor, contributing to various metabolic processes including the conversion of homocysteine to methionine.

In medical terms, betaine is also used as a dietary supplement and medication. Betaine hydrochloride is a form of betaine that is sometimes used as a supplement to help with digestion by providing additional stomach acid. Betaine anhydrous, on the other hand, is often used as a supplement for improving athletic performance and promoting liver health.

Betaine has also been studied for its potential role in protecting against various diseases, including cardiovascular disease, diabetes, and neurological disorders. However, more research is needed to fully understand its mechanisms of action and therapeutic potential.

Cycloserine is an antibiotic medication used to treat tuberculosis (TB) that is resistant to other antibiotics. It works by killing or inhibiting the growth of the bacteria that cause TB. Cycloserine is a second-line drug, which means it is used when first-line treatments have failed or are not effective.

The medical definition of Cycloserine is:

A bacteriostatic antibiotic derived from Streptomyces orchidaceus that inhibits gram-positive and gram-negative bacteria by interfering with peptidoglycan synthesis in the bacterial cell wall. It has been used to treat tuberculosis, but its use is limited due to its adverse effects, including neurotoxicity, which can manifest as seizures, dizziness, and confusion. Cycloserine is also used in the treatment of urinary tract infections and other bacterial infections that are resistant to other antibiotics. It is available in oral form and is typically taken two to four times a day.

Acetyl-CoA carboxylase (ACCA) is a biotin-dependent enzyme that plays a crucial role in fatty acid synthesis. It catalyzes the conversion of acetyl-CoA to malonyl-CoA, which is the first and rate-limiting step in the synthesis of long-chain fatty acids. The reaction catalyzed by ACCA is as follows:

acetyl-CoA + HCO3- + ATP + 2H+ --> malonyl-CoA + CoA + ADP + Pi + 2H2O

ACCA exists in two isoforms, a cytosolic form (ACC1) and a mitochondrial form (ACC2). ACC1 is primarily involved in fatty acid synthesis, while ACC2 is responsible for the regulation of fatty acid oxidation. The activity of ACCA is regulated by several factors, including phosphorylation/dephosphorylation, allosteric regulation, and transcriptional regulation. Dysregulation of ACCA has been implicated in various metabolic disorders, such as obesity, insulin resistance, and non-alcoholic fatty liver disease.

Sphingomyelins are a type of sphingolipids, which are a class of lipids that contain sphingosine as a backbone. Sphingomyelins are composed of phosphocholine or phosphoethanolamine bound to the ceramide portion of the molecule through a phosphodiester linkage. They are important components of cell membranes, particularly in the myelin sheath that surrounds nerve fibers. Sphingomyelins can be hydrolyzed by the enzyme sphingomyelinase to form ceramide and phosphorylcholine or phosphorylethanolamine. Abnormalities in sphingomyelin metabolism have been implicated in several diseases, including Niemann-Pick disease, a group of inherited lipid storage disorders.

Monounsaturated fatty acids (MUFAs) are a type of fatty acid that contains one double bond in its chemical structure. The presence of the double bond means that there is one less hydrogen atom, hence the term "unsaturated." In monounsaturated fats, the double bond occurs between the second and third carbon atoms in the chain, which makes them "mono"unsaturated.

MUFAs are considered to be a healthy type of fat because they can help reduce levels of harmful cholesterol (low-density lipoprotein or LDL) while maintaining levels of beneficial cholesterol (high-density lipoprotein or HDL). They have also been associated with a reduced risk of heart disease and improved insulin sensitivity.

Common sources of monounsaturated fats include olive oil, canola oil, avocados, nuts, and seeds. It is recommended to consume MUFAs as part of a balanced diet that includes a variety of nutrient-dense foods.

Azetidines are a class of organic compounds that contain a 4-membered saturated ring with two carbon atoms and two nitrogen atoms. The general structure of an azetidine is R-CH2-CH2-N-R', where R and R' can be hydrogen atoms or any other organic substituents.

Azetidines are relatively rare in nature, but they have attracted significant interest in the field of medicinal chemistry due to their unique structure and potential as building blocks for drug design. Some azetidine-containing compounds have been developed as drugs for various therapeutic indications, such as antibiotics, antivirals, and anti-inflammatory agents.

It's worth noting that the term 'azetidines' can also refer to the class of pharmaceutical compounds that contain an azetidine ring in their structure.

Oleic acid is a monounsaturated fatty acid that is commonly found in various natural oils such as olive oil, sunflower oil, and grapeseed oil. Its chemical formula is cis-9-octadecenoic acid, and it is a colorless liquid at room temperature. Oleic acid is an important component of human diet and has been shown to have potential health benefits, including reducing the risk of heart disease and improving immune function. It is also used in the manufacture of soaps, cosmetics, and other personal care products.

Mitochondria are specialized structures located inside cells that convert the energy from food into ATP (adenosine triphosphate), which is the primary form of energy used by cells. They are often referred to as the "powerhouses" of the cell because they generate most of the cell's supply of chemical energy. Mitochondria are also involved in various other cellular processes, such as signaling, differentiation, and apoptosis (programmed cell death).

Mitochondria have their own DNA, known as mitochondrial DNA (mtDNA), which is inherited maternally. This means that mtDNA is passed down from the mother to her offspring through the egg cells. Mitochondrial dysfunction has been linked to a variety of diseases and conditions, including neurodegenerative disorders, diabetes, and aging.

I am sorry for any confusion, but "Pentanoic Acids" is not a recognized medical term or concept. Pentanoic acid, also known as valeric acid, is an organic compound with the formula CH3CH2CH2CH2CO2H. It is a fatty acid with five carbon atoms, and it may have some uses in industry, but it does not have specific relevance to medical definition or healthcare.

Cyclic ethers are a type of organic compound that contain an ether functional group (-O-) within a cyclic (ring-shaped) structure. In a cyclic ether, one or more oxygen atoms are part of the ring, which can consist of various numbers of carbon atoms. The simplest example of a cyclic ether is oxirane, also known as ethylene oxide, which contains a three-membered ring with two carbon atoms and one oxygen atom.

Cyclic ethers have diverse applications in the chemical industry, including their use as building blocks for the synthesis of other chemicals, pharmaceuticals, and materials. Some cyclic ethers, like tetrahydrofuran (THF), are common solvents due to their ability to dissolve a wide range of organic compounds. However, some cyclic ethers can be hazardous or toxic, so they must be handled with care during laboratory work and industrial processes.

The myocardium is the middle layer of the heart wall, composed of specialized cardiac muscle cells that are responsible for pumping blood throughout the body. It forms the thickest part of the heart wall and is divided into two sections: the left ventricle, which pumps oxygenated blood to the rest of the body, and the right ventricle, which pumps deoxygenated blood to the lungs.

The myocardium contains several types of cells, including cardiac muscle fibers, connective tissue, nerves, and blood vessels. The muscle fibers are arranged in a highly organized pattern that allows them to contract in a coordinated manner, generating the force necessary to pump blood through the heart and circulatory system.

Damage to the myocardium can occur due to various factors such as ischemia (reduced blood flow), infection, inflammation, or genetic disorders. This damage can lead to several cardiac conditions, including heart failure, arrhythmias, and cardiomyopathy.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Skeletal muscle, also known as striated or voluntary muscle, is a type of muscle that is attached to bones by tendons or aponeuroses and functions to produce movements and support the posture of the body. It is composed of long, multinucleated fibers that are arranged in parallel bundles and are characterized by alternating light and dark bands, giving them a striped appearance under a microscope. Skeletal muscle is under voluntary control, meaning that it is consciously activated through signals from the nervous system. It is responsible for activities such as walking, running, jumping, and lifting objects.

Oleic acid is a monounsaturated fatty acid that is commonly found in various natural oils such as olive oil, sunflower oil, and peanut oil. Its chemical formula is cis-9-octadecenoic acid, and it is a colorless liquid at room temperature with a slight odor. Oleic acid is an important component of human diet and has been shown to have various health benefits, including reducing the risk of heart disease and improving immune function. It is also used in the manufacture of soaps, cosmetics, and other industrial products.

Clofibrate is a medication that belongs to the class of drugs known as fibrates. It is primarily used to lower elevated levels of cholesterol and other fats (lipids) in the blood, specifically low-density lipoprotein (LDL), or "bad" cholesterol, and triglycerides, while increasing high-density lipoprotein (HDL), or "good" cholesterol. Clofibrate works by reducing the production of very-low-density lipoproteins (VLDL) in the liver, which in turn lowers triglyceride levels and indirectly reduces LDL cholesterol levels.

Clofibrate is available in oral tablet form and is typically prescribed for patients with high cholesterol or triglycerides who are at risk of cardiovascular disease, such as those with a history of heart attacks, strokes, or peripheral artery disease. It is important to note that clofibrate should be used in conjunction with lifestyle modifications, including a healthy diet, regular exercise, and smoking cessation.

Like all medications, clofibrate can have side effects, some of which may be serious. Common side effects include stomach upset, diarrhea, gas, and changes in taste. Less commonly, clofibrate can cause more severe side effects such as liver or muscle damage, gallstones, and an increased risk of developing certain types of cancer. Patients taking clofibrate should be monitored regularly by their healthcare provider to ensure that the medication is working effectively and to monitor for any potential side effects.

Gene expression regulation, enzymologic refers to the biochemical processes and mechanisms that control the transcription and translation of specific genes into functional proteins or enzymes. This regulation is achieved through various enzymatic activities that can either activate or repress gene expression at different levels, such as chromatin remodeling, transcription factor activation, mRNA processing, and protein degradation.

Enzymologic regulation of gene expression involves the action of specific enzymes that catalyze chemical reactions involved in these processes. For example, histone-modifying enzymes can alter the structure of chromatin to make genes more or less accessible for transcription, while RNA polymerase and its associated factors are responsible for transcribing DNA into mRNA. Additionally, various enzymes are involved in post-transcriptional modifications of mRNA, such as splicing, capping, and tailing, which can affect the stability and translation of the transcript.

Overall, the enzymologic regulation of gene expression is a complex and dynamic process that allows cells to respond to changes in their environment and maintain proper physiological function.

Acyl-CoA oxidase is an enzyme that plays a crucial role in the breakdown of fatty acids within the body. It is located in the peroxisomes, which are small organelles found in the cells of living organisms. The primary function of acyl-CoA oxidase is to catalyze the initial step in the beta-oxidation of fatty acids, a process that involves the sequential removal of two-carbon units from fatty acid molecules in the form of acetyl-CoA.

The reaction catalyzed by acyl-CoA oxidase is as follows:

acyl-CoA + FAD → trans-2,3-dehydroacyl-CoA + FADH2 + H+

In this reaction, the enzyme removes a hydrogen atom from the fatty acyl-CoA molecule and transfers it to its cofactor, flavin adenine dinucleotide (FAD). This results in the formation of trans-2,3-dehydroacyl-CoA, FADH2, and a proton. The FADH2 produced during this reaction can then be used to generate ATP through the electron transport chain, while the trans-2,3-dehydroacyl-CoA undergoes further reactions in the beta-oxidation pathway.

There are two main isoforms of acyl-CoA oxidase found in humans: ACOX1 and ACOX2. ACOX1 is primarily responsible for oxidizing straight-chain fatty acids, while ACOX2 specializes in the breakdown of branched-chain fatty acids. Mutations in the genes encoding these enzymes can lead to various metabolic disorders, such as peroxisomal biogenesis disorders and Refsum disease.

3-Hydroxyacyl CoA Dehydrogenases (3-HADs) are a group of enzymes that play a crucial role in the beta-oxidation of fatty acids. These enzymes catalyze the third step of the beta-oxidation process, which involves the oxidation of 3-hydroxyacyl CoA to 3-ketoacyl CoA. This reaction is an essential part of the energy-generating process that occurs in the mitochondria of cells and allows for the breakdown of fatty acids into smaller molecules, which can then be used to produce ATP, the primary source of cellular energy.

There are several different isoforms of 3-HADs, each with specific substrate preferences and tissue distributions. The most well-known isoform is the mitochondrial 3-hydroxyacyl CoA dehydrogenase (M3HD), which is involved in the oxidation of medium and long-chain fatty acids. Other isoforms include the short-chain 3-hydroxyacyl CoA dehydrogenase (SCHAD) and the long-chain 3-hydroxyacyl CoA dehydrogenase (LCHAD), which are involved in the oxidation of shorter and longer chain fatty acids, respectively.

Deficiencies in 3-HADs can lead to serious metabolic disorders, such as 3-hydroxyacyl-CoA dehydrogenase deficiency (3-HAD deficiency), which is characterized by the accumulation of toxic levels of 3-hydroxyacyl CoAs in the body. Symptoms of this disorder can include hypoglycemia, muscle weakness, cardiomyopathy, and developmental delays. Early diagnosis and treatment of 3-HAD deficiency are essential to prevent serious complications and improve outcomes for affected individuals.

Acyl-CoA dehydrogenase, long-chain (LCHAD) is a medical term that refers to an enzyme found in the body that plays a crucial role in breaking down fatty acids for energy. This enzyme is responsible for catalyzing the first step in the beta-oxidation of long-chain fatty acids, which involves the removal of hydrogen atoms from the fatty acid molecule to create a double bond.

Mutations in the gene that encodes LCHAD can lead to deficiencies in the enzyme's activity, resulting in an accumulation of unmetabolized long-chain fatty acids in the body. This can cause a range of symptoms, including hypoglycemia (low blood sugar), muscle weakness, and liver dysfunction. In severe cases, LCHAD deficiency can lead to serious complications such as heart problems, developmental delays, and even death.

LCHAD deficiency is typically diagnosed through newborn screening or genetic testing, and treatment may involve dietary modifications, supplementation with medium-chain triglycerides (MCTs), and avoidance of fasting to prevent the breakdown of fatty acids for energy. In some cases, LCHAD deficiency may require more intensive treatments such as carnitine supplementation or liver transplantation.

Acyl-CoA dehydrogenase is a group of enzymes that play a crucial role in the body's energy production process. Specifically, they are involved in the breakdown of fatty acids within the cells.

More technically, acyl-CoA dehydrogenases catalyze the removal of electrons from the thiol group of acyl-CoAs, forming a trans-double bond and generating FADH2. This reaction is the first step in each cycle of fatty acid beta-oxidation, which occurs in the mitochondria of cells.

There are several different types of acyl-CoA dehydrogenases, each specific to breaking down different lengths of fatty acids. For example, very long-chain acyl-CoA dehydrogenase (VLCAD) is responsible for breaking down longer chain fatty acids, while medium-chain acyl-CoA dehydrogenase (MCAD) breaks down medium-length chains.

Deficiencies in these enzymes can lead to various metabolic disorders, such as MCAD deficiency or LC-FAOD (long-chain fatty acid oxidation disorders), which can cause symptoms like vomiting, lethargy, and muscle weakness, especially during periods of fasting or illness.

Triglycerides are the most common type of fat in the body, and they're found in the food we eat. They're carried in the bloodstream to provide energy to the cells in our body. High levels of triglycerides in the blood can increase the risk of heart disease, especially in combination with other risk factors such as high LDL (bad) cholesterol, low HDL (good) cholesterol, and high blood pressure.

It's important to note that while triglycerides are a type of fat, they should not be confused with cholesterol, which is a waxy substance found in the cells of our body. Both triglycerides and cholesterol are important for maintaining good health, but high levels of either can increase the risk of heart disease.

Triglyceride levels are measured through a blood test called a lipid panel or lipid profile. A normal triglyceride level is less than 150 mg/dL. Borderline-high levels range from 150 to 199 mg/dL, high levels range from 200 to 499 mg/dL, and very high levels are 500 mg/dL or higher.

Elevated triglycerides can be caused by various factors such as obesity, physical inactivity, excessive alcohol consumption, smoking, and certain medical conditions like diabetes, hypothyroidism, and kidney disease. Medications such as beta-blockers, steroids, and diuretics can also raise triglyceride levels.

Lifestyle changes such as losing weight, exercising regularly, eating a healthy diet low in saturated and trans fats, avoiding excessive alcohol consumption, and quitting smoking can help lower triglyceride levels. In some cases, medication may be necessary to reduce triglycerides to recommended levels.

I'm sorry for any confusion, but "Rats, Inbred BUF" is not a standard medical term or abbreviation in human or animal medicine that I'm aware of. It's possible that you may be referring to a specific strain of inbred rats used in scientific research. "BUF" could potentially stand for "Buehler University of Florida," which is a strain of inbred rats developed at the University of Florida. These rats are often used in studies related to cardiovascular and renal physiology. However, I would recommend consulting the original source or contacting a professional in the field to confirm the specific context and accurate definition.

A muscle is a soft tissue in our body that contracts to produce force and motion. It is composed mainly of specialized cells called muscle fibers, which are bound together by connective tissue. There are three types of muscles: skeletal (voluntary), smooth (involuntary), and cardiac. Skeletal muscles attach to bones and help in movement, while smooth muscles are found within the walls of organs and blood vessels, helping with functions like digestion and circulation. Cardiac muscle is the specific type that makes up the heart, allowing it to pump blood throughout the body.

"Wistar rats" are a strain of albino rats that are widely used in laboratory research. They were developed at the Wistar Institute in Philadelphia, USA, and were first introduced in 1906. Wistar rats are outbred, which means that they are genetically diverse and do not have a fixed set of genetic characteristics like inbred strains.

Wistar rats are commonly used as animal models in biomedical research because of their size, ease of handling, and relatively low cost. They are used in a wide range of research areas, including toxicology, pharmacology, nutrition, cancer, cardiovascular disease, and behavioral studies. Wistar rats are also used in safety testing of drugs, medical devices, and other products.

Wistar rats are typically larger than many other rat strains, with males weighing between 500-700 grams and females weighing between 250-350 grams. They have a lifespan of approximately 2-3 years. Wistar rats are also known for their docile and friendly nature, making them easy to handle and work with in the laboratory setting.

Messenger RNA (mRNA) is a type of RNA (ribonucleic acid) that carries genetic information copied from DNA in the form of a series of three-base code "words," each of which specifies a particular amino acid. This information is used by the cell's machinery to construct proteins, a process known as translation. After being transcribed from DNA, mRNA travels out of the nucleus to the ribosomes in the cytoplasm where protein synthesis occurs. Once the protein has been synthesized, the mRNA may be degraded and recycled. Post-transcriptional modifications can also occur to mRNA, such as alternative splicing and addition of a 5' cap and a poly(A) tail, which can affect its stability, localization, and translation efficiency.

"Pichia" is a genus of single-celled yeast organisms that are commonly found in various environments, including on plant and animal surfaces, in soil, and in food. Some species of Pichia are capable of causing human infection, particularly in individuals with weakened immune systems. These infections can include fungemia (bloodstream infections), pneumonia, and urinary tract infections.

Pichia species are important in a variety of industrial processes, including the production of alcoholic beverages, biofuels, and enzymes. They are also used as model organisms for research in genetics and cell biology.

It's worth noting that Pichia was previously classified under the genus "Candida," but it has since been reclassified due to genetic differences between the two groups.

Oxygen consumption, also known as oxygen uptake, is the amount of oxygen that is consumed or utilized by the body during a specific period of time, usually measured in liters per minute (L/min). It is a common measurement used in exercise physiology and critical care medicine to assess an individual's aerobic metabolism and overall health status.

In clinical settings, oxygen consumption is often measured during cardiopulmonary exercise testing (CPET) to evaluate cardiovascular function, pulmonary function, and exercise capacity in patients with various medical conditions such as heart failure, chronic obstructive pulmonary disease (COPD), and other respiratory or cardiac disorders.

During exercise, oxygen is consumed by the muscles to generate energy through a process called oxidative phosphorylation. The amount of oxygen consumed during exercise can provide important information about an individual's fitness level, exercise capacity, and overall health status. Additionally, measuring oxygen consumption can help healthcare providers assess the effectiveness of treatments and rehabilitation programs in patients with various medical conditions.

PPAR-alpha (Peroxisome Proliferator-Activated Receptor alpha) is a type of nuclear receptor protein that functions as a transcription factor, regulating the expression of specific genes involved in lipid metabolism. It plays a crucial role in the breakdown of fatty acids and the synthesis of high-density lipoproteins (HDL or "good" cholesterol) in the liver. PPAR-alpha activation also has anti-inflammatory effects, making it a potential therapeutic target for metabolic disorders such as diabetes, hyperlipidemia, and non-alcoholic fatty liver disease (NAFLD).

Coenzyme A (CoA) ligases, also known as CoA synthetases, are a class of enzymes that activate acyl groups, such as fatty acids and amino acids, by forming a thioester bond with coenzyme A. This activation is an essential step in various metabolic pathways, including fatty acid oxidation, amino acid catabolism, and the synthesis of several important compounds like steroids and acetylcholine.

CoA ligases catalyze the following reaction:

acyl group + ATP + CoA ↔ acyl-CoA + AMP + PP~i~

In this reaction, an acyl group (R-) from a carboxylic acid is linked to the thiol (-SH) group of coenzyme A through a high-energy thioester bond. The energy required for this activation is provided by the hydrolysis of ATP to AMP and inorganic pyrophosphate (PP~i~).

CoA ligases are classified into three main types based on the nature of the acyl group they activate:

1. Acyl-CoA synthetases (or long-chain fatty acid CoA ligases) activate long-chain fatty acids, typically containing 12 or more carbon atoms.
2. Aminoacyl-CoA synthetases activate amino acids to form aminoacyl-CoAs, which are essential intermediates in the catabolism of certain amino acids.
3. Short-chain specific CoA ligases activate short-chain fatty acids (up to 6 carbon atoms) and other acyl groups like acetate or propionate.

These enzymes play a crucial role in maintaining cellular energy homeostasis, metabolism, and the synthesis of various essential biomolecules.

Substrate specificity in the context of medical biochemistry and enzymology refers to the ability of an enzyme to selectively bind and catalyze a chemical reaction with a particular substrate (or a group of similar substrates) while discriminating against other molecules that are not substrates. This specificity arises from the three-dimensional structure of the enzyme, which has evolved to match the shape, charge distribution, and functional groups of its physiological substrate(s).

Substrate specificity is a fundamental property of enzymes that enables them to carry out highly selective chemical transformations in the complex cellular environment. The active site of an enzyme, where the catalysis takes place, has a unique conformation that complements the shape and charge distribution of its substrate(s). This ensures efficient recognition, binding, and conversion of the substrate into the desired product while minimizing unwanted side reactions with other molecules.

Substrate specificity can be categorized as:

1. Absolute specificity: An enzyme that can only act on a single substrate or a very narrow group of structurally related substrates, showing no activity towards any other molecule.
2. Group specificity: An enzyme that prefers to act on a particular functional group or class of compounds but can still accommodate minor structural variations within the substrate.
3. Broad or promiscuous specificity: An enzyme that can act on a wide range of structurally diverse substrates, albeit with varying catalytic efficiencies.

Understanding substrate specificity is crucial for elucidating enzymatic mechanisms, designing drugs that target specific enzymes or pathways, and developing biotechnological applications that rely on the controlled manipulation of enzyme activities.

Bezafibrate is a medication that belongs to a class of drugs called fibrates. It is primarily used to treat high cholesterol and related conditions, such as hyperlipidemia and mixed dyslipidemia. The medication works by reducing the levels of triglycerides and increasing the levels of "good" cholesterol (HDL) in the blood.

Bezafibrate achieves this effect by activating certain receptors in the body, known as peroxisome proliferator-activated receptors (PPARs), which play a role in regulating lipid metabolism. By binding to these receptors, bezafibrate helps to promote the breakdown of fats and reduce the production of cholesterol in the liver.

It is important to note that bezafibrate should be used in conjunction with lifestyle modifications, such as a healthy diet and regular exercise, to effectively manage high cholesterol and related conditions. Additionally, it may interact with other medications, so it is essential to inform your healthcare provider of all the drugs you are taking before starting bezafibrate therapy.

As with any medication, bezafibrate can cause side effects, including gastrointestinal symptoms such as nausea, diarrhea, and abdominal pain, as well as headaches, muscle cramps, and skin rashes. In rare cases, it may also cause more serious side effects, such as liver or kidney damage, so regular monitoring of liver and kidney function is recommended during treatment.

Overall, bezafibrate is a valuable tool in the management of high cholesterol and related conditions, but it should be used under the guidance and supervision of a healthcare professional to ensure safe and effective use.

Esterification is a chemical reaction that involves the conversion of an alcohol and a carboxylic acid into an ester, typically through the removal of a molecule of water. This reaction is often catalyzed by an acid or a base, and it is a key process in organic chemistry. Esters are commonly found in nature and are responsible for the fragrances of many fruits and flowers. They are also important in the production of various industrial and consumer products, including plastics, resins, and perfumes.

Benzyl alcohol is a aromatic alcohol with the chemical formula C6H5CH2OH. It is a colorless liquid with a characteristic, mildly unpleasant odor. Benzyl alcohol is used as a solvent and as an intermediate in the production of other chemicals. In medicine, it is used as a local anesthetic and antimicrobial agent. It can be found in some personal care products, such as cosmetics, shampoos, and sunscreens, as well as in topical medications and intravenous medications.

Glyoxylates are organic compounds that are intermediates in various metabolic pathways, including the glyoxylate cycle. The glyoxylate cycle is a modified version of the Krebs cycle (also known as the citric acid cycle) and is found in plants, bacteria, and some fungi.

Glyoxylates are formed from the breakdown of certain amino acids or from the oxidation of one-carbon units. They can be converted into glycine, an important amino acid involved in various metabolic processes. In the glyoxylate cycle, glyoxylates are combined with acetyl-CoA to form malate and succinate, which can then be used to synthesize glucose or other organic compounds.

Abnormal accumulation of glyoxylates in the body can lead to the formation of calcium oxalate crystals, which can cause kidney stones and other health problems. Certain genetic disorders, such as primary hyperoxaluria, can result in overproduction of glyoxylates and increased risk of kidney stone formation.

Detergents are cleaning agents that are often used to remove dirt, grease, and stains from various surfaces. They contain one or more surfactants, which are compounds that lower the surface tension between two substances, such as water and oil, allowing them to mix more easily. This makes it possible for detergents to lift and suspend dirt particles in water so they can be rinsed away.

Detergents may also contain other ingredients, such as builders, which help to enhance the cleaning power of the surfactants by softening hard water or removing mineral deposits. Some detergents may also include fragrances, colorants, and other additives to improve their appearance or performance.

In a medical context, detergents are sometimes used as disinfectants or antiseptics, as they can help to kill bacteria, viruses, and other microorganisms on surfaces. However, it is important to note that not all detergents are effective against all types of microorganisms, and some may even be toxic or harmful if used improperly.

It is always important to follow the manufacturer's instructions when using any cleaning product, including detergents, to ensure that they are used safely and effectively.

Ceramidases are a group of enzymes that catalyze the hydrolysis of ceramide into sphingosine and free fatty acids. Ceramides are important components of cell membranes, and their metabolism is tightly regulated in cells. The hydrolysis of ceramide by ceramidases produces sphingosine, which can be further phosphorylated to form sphingosine-1-phosphate (S1P), a signaling molecule involved in various cellular processes such as proliferation, differentiation, and survival.

There are several types of ceramidases that have been identified, including acid ceramidase, neutral ceramidase, and alkaline ceramidase. These enzymes differ in their subcellular localization, substrate specificity, and physiological functions. Dysregulation of ceramidase activity has been implicated in various diseases, including cancer, neurodegenerative disorders, and inflammatory conditions. Therefore, ceramidases are considered as potential therapeutic targets for the treatment of these diseases.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Nonesterified fatty acids (NEFA), also known as free fatty acids (FFA), refer to fatty acid molecules that are not bound to glycerol in the form of triglycerides or other esters. In the bloodstream, NEFAs are transported while bound to albumin and can serve as a source of energy for peripheral tissues. Under normal physiological conditions, NEFA levels are tightly regulated by the body; however, elevated NEFA levels have been associated with various metabolic disorders such as insulin resistance, obesity, and type 2 diabetes.

Vitamin B deficiency refers to a condition where an individual's body lacks adequate amounts of one or more essential Vitamin B compounds, including Vitamin B1 (thiamin), Vitamin B2 (riboflavin), Vitamin B3 (niacin), Vitamin B5 (pantothenic acid), Vitamin B6 (pyridoxine), Vitamin B7 (biotin), Vitamin B9 (folate), and Vitamin B12 (cobalamin). These water-soluble vitamins play crucial roles in various bodily functions, such as energy production, nerve function, DNA repair, and the formation of red blood cells.

Deficiency in any of these Vitamin B compounds can lead to specific health issues. For instance:

1. Vitamin B1 (thiamin) deficiency can cause beriberi, a condition characterized by muscle weakness, peripheral neuropathy, and heart failure.
2. Vitamin B2 (riboflavin) deficiency may result in ariboflavinosis, which presents with inflammation of the mouth and tongue, anemia, and skin disorders.
3. Vitamin B3 (niacin) deficiency can lead to pellagra, marked by diarrhea, dermatitis, dementia, and, if left untreated, death.
4. Vitamin B5 (pantothenic acid) deficiency is rare but can cause acne-like skin lesions and neurological symptoms.
5. Vitamin B6 (pyridoxine) deficiency may result in anemia, peripheral neuropathy, seizures, and skin disorders.
6. Vitamin B7 (biotin) deficiency can cause hair loss, skin rashes, and neurological symptoms.
7. Vitamin B9 (folate) deficiency can lead to megaloblastic anemia, neural tube defects in fetuses during pregnancy, and increased homocysteine levels, which may contribute to cardiovascular disease.
8. Vitamin B12 (cobalamin) deficiency can cause pernicious anemia, characterized by fatigue, weakness, neurological symptoms, and, if left untreated, irreversible nerve damage.

Deficiencies in these vitamins can arise from inadequate dietary intake, malabsorption syndromes, or certain medications that interfere with absorption or metabolism. It is essential to maintain a balanced diet and consider supplementation if necessary under the guidance of a healthcare professional.

Fumonisins are a type of mycotoxin, which are toxic compounds produced by certain types of mold or fungi. They are primarily produced by Fusarium verticillioides and Fusarium proliferatum, which are common contaminants of crops such as corn, wheat, and rice.

Fumonisins are characterized by their long-chain structure and have been associated with a variety of adverse health effects in both humans and animals. The most well-known fumonisin is FB1 (fumonisin B1), which has been shown to be toxic to the liver and kidneys, as well as being linked to neural tube defects in developing fetuses.

Exposure to fumonisins can occur through the consumption of contaminated food or feed, and they have been found in a variety of agricultural products, including cornmeal, grits, and cereals. In addition to their potential health effects, fumonisins can also negatively impact crop yields and economic losses for farmers. As such, monitoring and controlling the levels of fumonisins in food and feed is an important public health and agricultural concern.

I couldn't find a medical definition specifically for "Diabetes Mellitus, Experimental." However, I can provide you with information about experimental diabetes research and its relevance to understanding the disease.

Experimental diabetes models are used in biomedical research to study the pathophysiology of diabetes mellitus and to test potential therapies or treatments. These models can be broadly categorized into two types: chemically-induced and genetically modified.

1. Chemically-induced diabetes models: These involve administering chemicals, such as alloxan or streptozotocin, to animals (commonly mice or rats) to destroy their pancreatic β-cells, which produce insulin. This results in hyperglycemia and symptoms similar to those seen in type 1 diabetes in humans.
2. Genetically modified diabetes models: These involve altering the genes of animals (commonly mice) to create a diabetes phenotype. Examples include non-obese diabetic (NOD) mice, which develop an autoimmune form of diabetes similar to human type 1 diabetes, and various strains of obese mice with insulin resistance, such as ob/ob or db/db mice, which model aspects of type 2 diabetes.

These experimental models help researchers better understand the mechanisms behind diabetes development and progression, identify new therapeutic targets, and test potential treatments before moving on to human clinical trials. However, it's essential to recognize that these models may not fully replicate all aspects of human diabetes, so findings from animal studies should be interpreted with caution.

Energy metabolism is the process by which living organisms produce and consume energy to maintain life. It involves a series of chemical reactions that convert nutrients from food, such as carbohydrates, fats, and proteins, into energy in the form of adenosine triphosphate (ATP).

The process of energy metabolism can be divided into two main categories: catabolism and anabolism. Catabolism is the breakdown of nutrients to release energy, while anabolism is the synthesis of complex molecules from simpler ones using energy.

There are three main stages of energy metabolism: glycolysis, the citric acid cycle (also known as the Krebs cycle), and oxidative phosphorylation. Glycolysis occurs in the cytoplasm of the cell and involves the breakdown of glucose into pyruvate, producing a small amount of ATP and nicotinamide adenine dinucleotide (NADH). The citric acid cycle takes place in the mitochondria and involves the further breakdown of pyruvate to produce more ATP, NADH, and carbon dioxide. Oxidative phosphorylation is the final stage of energy metabolism and occurs in the inner mitochondrial membrane. It involves the transfer of electrons from NADH and other electron carriers to oxygen, which generates a proton gradient across the membrane. This gradient drives the synthesis of ATP, producing the majority of the cell's energy.

Overall, energy metabolism is a complex and essential process that allows organisms to grow, reproduce, and maintain their bodily functions. Disruptions in energy metabolism can lead to various diseases, including diabetes, obesity, and neurodegenerative disorders.

Rhabdomyolysis is a medical condition characterized by the breakdown and degeneration of skeletal muscle fibers, leading to the release of their intracellular contents into the bloodstream. This can result in various complications, including electrolyte imbalances, kidney injury or failure, and potentially life-threatening conditions if not promptly diagnosed and treated.

The process of rhabdomyolysis typically involves three key components:

1. Muscle injury: Direct trauma, excessive exertion, prolonged immobilization, infections, metabolic disorders, toxins, or medications can cause muscle damage, leading to the release of intracellular components into the bloodstream.
2. Release of muscle contents: When muscle fibers break down, they release various substances, such as myoglobin, creatine kinase (CK), lactate dehydrogenase (LDH), aldolase, and potassium ions. Myoglobin is a protein that can cause kidney damage when present in high concentrations in the bloodstream, particularly when it is filtered through the kidneys and deposits in the renal tubules.
3. Systemic effects: The release of muscle contents into the bloodstream can lead to various systemic complications, such as electrolyte imbalances (particularly hyperkalemia), acidosis, hypocalcemia, and kidney injury or failure due to myoglobin-induced tubular damage.

Symptoms of rhabdomyolysis can vary widely depending on the severity and extent of muscle damage but may include muscle pain, weakness, swelling, stiffness, dark urine, and tea-colored or cola-colored urine due to myoglobinuria. In severe cases, patients may experience symptoms related to kidney failure, such as nausea, vomiting, fatigue, and decreased urine output.

Diagnosis of rhabdomyolysis typically involves measuring blood levels of muscle enzymes (such as CK and LDH) and evaluating renal function through blood tests and urinalysis. Treatment generally focuses on addressing the underlying cause of muscle damage, maintaining fluid balance, correcting electrolyte imbalances, and preventing or managing kidney injury.

Diabetic ketoacidosis (DKA) is a serious metabolic complication characterized by the triad of hyperglycemia, metabolic acidosis, and increased ketone bodies. It primarily occurs in individuals with diabetes mellitus type 1, but it can also be seen in some people with diabetes mellitus type 2, particularly during severe illness or surgery.

The condition arises when there is a significant lack of insulin in the body, which impairs the ability of cells to take up glucose for energy production. As a result, the body starts breaking down fatty acids to produce energy, leading to an increase in ketone bodies (acetoacetate, beta-hydroxybutyrate, and acetone) in the bloodstream. This process is called ketosis.

In DKA, the excessive production of ketone bodies results in metabolic acidosis, which is characterized by a lower than normal pH level in the blood (< 7.35) and an elevated serum bicarbonate level (< 18 mEq/L). The hyperglycemia in DKA is due to both increased glucose production and decreased glucose utilization by cells, which can lead to severe dehydration and electrolyte imbalances.

Symptoms of diabetic ketoacidosis include excessive thirst, frequent urination, nausea, vomiting, abdominal pain, fatigue, fruity breath odor, and altered mental status. If left untreated, DKA can progress to coma and even lead to death. Treatment typically involves administering insulin, fluid replacement, and electrolyte management in a hospital setting.

Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.

Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.

These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.

Western blotting is a laboratory technique used in molecular biology to detect and quantify specific proteins in a mixture of many different proteins. This technique is commonly used to confirm the expression of a protein of interest, determine its size, and investigate its post-translational modifications. The name "Western" blotting distinguishes this technique from Southern blotting (for DNA) and Northern blotting (for RNA).

The Western blotting procedure involves several steps:

1. Protein extraction: The sample containing the proteins of interest is first extracted, often by breaking open cells or tissues and using a buffer to extract the proteins.
2. Separation of proteins by electrophoresis: The extracted proteins are then separated based on their size by loading them onto a polyacrylamide gel and running an electric current through the gel (a process called sodium dodecyl sulfate-polyacrylamide gel electrophoresis or SDS-PAGE). This separates the proteins according to their molecular weight, with smaller proteins migrating faster than larger ones.
3. Transfer of proteins to a membrane: After separation, the proteins are transferred from the gel onto a nitrocellulose or polyvinylidene fluoride (PVDF) membrane using an electric current in a process called blotting. This creates a replica of the protein pattern on the gel but now immobilized on the membrane for further analysis.
4. Blocking: The membrane is then blocked with a blocking agent, such as non-fat dry milk or bovine serum albumin (BSA), to prevent non-specific binding of antibodies in subsequent steps.
5. Primary antibody incubation: A primary antibody that specifically recognizes the protein of interest is added and allowed to bind to its target protein on the membrane. This step may be performed at room temperature or 4°C overnight, depending on the antibody's properties.
6. Washing: The membrane is washed with a buffer to remove unbound primary antibodies.
7. Secondary antibody incubation: A secondary antibody that recognizes the primary antibody (often coupled to an enzyme or fluorophore) is added and allowed to bind to the primary antibody. This step may involve using a horseradish peroxidase (HRP)-conjugated or alkaline phosphatase (AP)-conjugated secondary antibody, depending on the detection method used later.
8. Washing: The membrane is washed again to remove unbound secondary antibodies.
9. Detection: A detection reagent is added to visualize the protein of interest by detecting the signal generated from the enzyme-conjugated or fluorophore-conjugated secondary antibody. This can be done using chemiluminescent, colorimetric, or fluorescent methods.
10. Analysis: The resulting image is analyzed to determine the presence and quantity of the protein of interest in the sample.

Western blotting is a powerful technique for identifying and quantifying specific proteins within complex mixtures. It can be used to study protein expression, post-translational modifications, protein-protein interactions, and more. However, it requires careful optimization and validation to ensure accurate and reproducible results.

Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

Sphingomyelin phosphodiesterase is an enzyme that catalyzes the hydrolysis of sphingomyelin, a sphingolipid found in animal tissues, into ceramide and phosphorylcholine. This enzyme plays a crucial role in the metabolism of sphingomyelin and the regulation of cellular processes such as apoptosis, differentiation, and inflammation.

There are several isoforms of this enzyme, including acid sphingomyelinase (ASM) and neutral sphingomyelinase (NSM), which differ in their subcellular localization, regulation, and physiological functions. Deficiencies or dysfunctions in sphingomyelin phosphodiesterase activity have been implicated in various diseases, such as Niemann-Pick disease, atherosclerosis, and cancer.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Catalysis is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst, which remains unchanged at the end of the reaction. A catalyst lowers the activation energy required for the reaction to occur, thereby allowing the reaction to proceed more quickly and efficiently. This can be particularly important in biological systems, where enzymes act as catalysts to speed up metabolic reactions that are essential for life.

Ketones are organic compounds that contain a carbon atom bound to two oxygen atoms and a central carbon atom bonded to two additional carbon groups through single bonds. In the context of human physiology, ketones are primarily produced as byproducts when the body breaks down fat for energy in a process called ketosis.

Specifically, under conditions of low carbohydrate availability or prolonged fasting, the liver converts fatty acids into ketone bodies, which can then be used as an alternative fuel source for the brain and other organs. The three main types of ketones produced in the human body are acetoacetate, beta-hydroxybutyrate, and acetone.

Elevated levels of ketones in the blood, known as ketonemia, can occur in various medical conditions such as diabetes, starvation, alcoholism, and high-fat/low-carbohydrate diets. While moderate levels of ketosis are generally considered safe, severe ketosis can lead to a life-threatening condition called diabetic ketoacidosis (DKA) in people with diabetes.

Acylation is a medical and biological term that refers to the process of introducing an acyl group (-CO-) into a molecule. This process can occur naturally or it can be induced through chemical reactions. In the context of medicine and biology, acylation often occurs during post-translational modifications of proteins, where an acyl group is added to specific amino acid residues, altering the protein's function, stability, or localization.

An example of acylation in medicine is the administration of neuraminidase inhibitors, such as oseltamivir (Tamiflu), for the treatment and prevention of influenza. These drugs work by inhibiting the activity of the viral neuraminidase enzyme, which is essential for the release of newly formed virus particles from infected cells. Oseltamivir is administered orally as an ethyl ester prodrug, which is then hydrolyzed in the body to form the active acylated metabolite that inhibits the viral neuraminidase.

In summary, acylation is a vital process in medicine and biology, with implications for drug design, protein function, and post-translational modifications.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

"Newborn animals" refers to the very young offspring of animals that have recently been born. In medical terminology, newborns are often referred to as "neonates," and they are classified as such from birth until about 28 days of age. During this time period, newborn animals are particularly vulnerable and require close monitoring and care to ensure their survival and healthy development.

The specific needs of newborn animals can vary widely depending on the species, but generally, they require warmth, nutrition, hydration, and protection from harm. In many cases, newborns are unable to regulate their own body temperature or feed themselves, so they rely heavily on their mothers for care and support.

In medical settings, newborn animals may be examined and treated by veterinarians to ensure that they are healthy and receiving the care they need. This can include providing medical interventions such as feeding tubes, antibiotics, or other treatments as needed to address any health issues that arise. Overall, the care and support of newborn animals is an important aspect of animal medicine and conservation efforts.

Ergothioneine is a naturally occurring antioxidant compound that is found in various foods such as mushrooms, some types of beans, and certain grains. It is also produced by some bacteria that live in the human body. Ergothioneine has been shown to have potential health benefits due to its antioxidant properties, which help protect cells from damage caused by free radicals. Some studies suggest that ergothioneine may have neuroprotective effects and could play a role in preventing neurodegenerative diseases such as Parkinson's and Alzheimer's. However, more research is needed to fully understand the potential health benefits of this compound.

Octoxynol is a type of surfactant, which is a compound that lowers the surface tension between two substances, such as oil and water. It is a synthetic chemical that is composed of repeating units of octylphenoxy polyethoxy ethanol.

Octoxynol is commonly used in medical applications as a spermicide, as it is able to disrupt the membrane of sperm cells and prevent them from fertilizing an egg. It is found in some contraceptive creams, gels, and films, and is also used as an ingredient in some personal care products such as shampoos and toothpastes.

In addition to its use as a spermicide, octoxynol has been studied for its potential antimicrobial properties, and has been shown to have activity against certain viruses, bacteria, and fungi. However, its use as an antimicrobial agent is not widely established.

It's important to note that octoxynol can cause irritation and allergic reactions in some people, and should be used with caution. Additionally, there is some concern about the potential for octoxynol to have harmful effects on the environment, as it has been shown to be toxic to aquatic organisms at high concentrations.

A medical definition of 'food' would be:

"Substances consumed by living organisms, usually in the form of meals, which contain necessary nutrients such as carbohydrates, proteins, fats, vitamins, minerals, and water. These substances are broken down during digestion to provide energy, build and repair tissues, and regulate bodily functions."

It's important to note that while this is a medical definition, it also aligns with common understanding of what food is.

In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.

For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.

Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.

Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.

Oxidoreductases are a class of enzymes that catalyze oxidation-reduction reactions, which involve the transfer of electrons from one molecule (the reductant) to another (the oxidant). These enzymes play a crucial role in various biological processes, including energy production, metabolism, and detoxification.

The oxidoreductase-catalyzed reaction typically involves the donation of electrons from a reducing agent (donor) to an oxidizing agent (acceptor), often through the transfer of hydrogen atoms or hydride ions. The enzyme itself does not undergo any permanent chemical change during this process, but rather acts as a catalyst to lower the activation energy required for the reaction to occur.

Oxidoreductases are classified and named based on the type of electron donor or acceptor involved in the reaction. For example, oxidoreductases that act on the CH-OH group of donors are called dehydrogenases, while those that act on the aldehyde or ketone groups are called oxidases. Other examples include reductases, peroxidases, and catalases.

Understanding the function and regulation of oxidoreductases is important for understanding various physiological processes and developing therapeutic strategies for diseases associated with impaired redox homeostasis, such as cancer, neurodegenerative disorders, and cardiovascular disease.

Complementary DNA (cDNA) is a type of DNA that is synthesized from a single-stranded RNA molecule through the process of reverse transcription. In this process, the enzyme reverse transcriptase uses an RNA molecule as a template to synthesize a complementary DNA strand. The resulting cDNA is therefore complementary to the original RNA molecule and is a copy of its coding sequence, but it does not contain non-coding regions such as introns that are present in genomic DNA.

Complementary DNA is often used in molecular biology research to study gene expression, protein function, and other genetic phenomena. For example, cDNA can be used to create cDNA libraries, which are collections of cloned cDNA fragments that represent the expressed genes in a particular cell type or tissue. These libraries can then be screened for specific genes or gene products of interest. Additionally, cDNA can be used to produce recombinant proteins in heterologous expression systems, allowing researchers to study the structure and function of proteins that may be difficult to express or purify from their native sources.

DNA primers are short single-stranded DNA molecules that serve as a starting point for DNA synthesis. They are typically used in laboratory techniques such as the polymerase chain reaction (PCR) and DNA sequencing. The primer binds to a complementary sequence on the DNA template through base pairing, providing a free 3'-hydroxyl group for the DNA polymerase enzyme to add nucleotides and synthesize a new strand of DNA. This allows for specific and targeted amplification or analysis of a particular region of interest within a larger DNA molecule.

3-Hydroxybutyric acid, also known as β-hydroxybutyric acid, is a type of ketone body that is produced in the liver during the metabolism of fatty acids. It is a colorless, slightly water-soluble compound with a bitter taste and an unpleasant odor.

In the body, 3-hydroxybutyric acid is produced when there is not enough glucose available to meet the body's energy needs, such as during fasting, starvation, or prolonged intense exercise. It can also be produced in large amounts in people with uncontrolled diabetes, particularly during a condition called diabetic ketoacidosis.

3-Hydroxybutyric acid is an important source of energy for the brain and other organs during periods of low glucose availability. However, high levels of 3-hydroxybutyric acid in the blood can lead to a condition called ketosis, which can cause symptoms such as nausea, vomiting, abdominal pain, and confusion. If left untreated, ketosis can progress to diabetic ketoacidosis, a potentially life-threatening complication of diabetes.

Microsomes are subcellular membranous vesicles that are obtained as a byproduct during the preparation of cellular homogenates. They are not naturally occurring structures within the cell, but rather formed due to fragmentation of the endoplasmic reticulum (ER) during laboratory procedures. Microsomes are widely used in various research and scientific studies, particularly in the fields of biochemistry and pharmacology.

Microsomes are rich in enzymes, including the cytochrome P450 system, which is involved in the metabolism of drugs, toxins, and other xenobiotics. These enzymes play a crucial role in detoxifying foreign substances and eliminating them from the body. As such, microsomes serve as an essential tool for studying drug metabolism, toxicity, and interactions, allowing researchers to better understand and predict the effects of various compounds on living organisms.

Enzyme inhibitors are substances that bind to an enzyme and decrease its activity, preventing it from catalyzing a chemical reaction in the body. They can work by several mechanisms, including blocking the active site where the substrate binds, or binding to another site on the enzyme to change its shape and prevent substrate binding. Enzyme inhibitors are often used as drugs to treat various medical conditions, such as high blood pressure, abnormal heart rhythms, and bacterial infections. They can also be found naturally in some foods and plants, and can be used in research to understand enzyme function and regulation.

"Saccharomyces cerevisiae" is not typically considered a medical term, but it is a scientific name used in the field of microbiology. It refers to a species of yeast that is commonly used in various industrial processes, such as baking and brewing. It's also widely used in scientific research due to its genetic tractability and eukaryotic cellular organization.

However, it does have some relevance to medical fields like medicine and nutrition. For example, certain strains of S. cerevisiae are used as probiotics, which can provide health benefits when consumed. They may help support gut health, enhance the immune system, and even assist in the digestion of certain nutrients.

In summary, "Saccharomyces cerevisiae" is a species of yeast with various industrial and potential medical applications.

Mitochondrial membranes refer to the double-layered structure that surrounds the mitochondrion, an organelle found in the cells of most eukaryotes. The outer mitochondrial membrane is a smooth, porous membrane that allows small molecules and ions to pass through freely, while the inner mitochondrial membrane is highly folded and selectively permeable, controlling the movement of larger molecules and maintaining the electrochemical gradient necessary for ATP synthesis. The space between the two membranes is called the intermembrane space, and the space within the inner membrane is called the matrix. Together, these membranes play a crucial role in energy production, metabolism, and cellular homeostasis.

AMP-activated protein kinases (AMPK) are a group of heterotrimeric enzymes that play a crucial role in cellular energy homeostasis. They are composed of a catalytic subunit (α) and two regulatory subunits (β and γ). AMPK is activated under conditions of low energy charge, such as ATP depletion, hypoxia, or exercise, through an increase in the AMP:ATP ratio.

Once activated, AMPK phosphorylates and regulates various downstream targets involved in metabolic pathways, including glycolysis, fatty acid oxidation, and protein synthesis. This results in the inhibition of energy-consuming processes and the promotion of energy-producing processes, ultimately helping to restore cellular energy balance.

AMPK has been implicated in a variety of physiological processes, including glucose and lipid metabolism, autophagy, mitochondrial biogenesis, and inflammation. Dysregulation of AMPK activity has been linked to several diseases, such as diabetes, obesity, cancer, and neurodegenerative disorders. Therefore, AMPK is an attractive target for therapeutic interventions in these conditions.

Hydroxymethylglutaryl-CoA Synthase (HMG-CoA Synthase) is a key enzyme in the cholesterol biosynthesis pathway. It catalyzes the reaction of acetoacetyl-CoA and acetyl-CoA to form HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A), which is a crucial intermediate in the synthesis of cholesterol, ketone bodies, and other isoprenoids.

There are two isoforms of this enzyme: HMG-CoA synthase 1 (HMGCS1) and HMG-CoA synthase 2 (HMGCS2). HMGCS1 is primarily expressed in the liver and is involved in cholesterol synthesis, while HMGCS2 is mainly found in the brain, kidney, and liver, where it plays a role in ketone body synthesis during periods of fasting or low-carbohydrate diets.

Defects in HMG-CoA synthase can lead to metabolic disorders, such as hypocholesterolemia (low cholesterol levels) and hyperketonemia (elevated ketone bodies). Additionally, inhibitors of HMG-CoA synthase are used as cholesterol-lowering drugs, known as statins, to treat conditions like hyperlipidemia and prevent cardiovascular diseases.

Reye Syndrome is a rare but serious condition that primarily affects children and teenagers, particularly those who have recently recovered from viral infections such as chickenpox or flu. It is characterized by rapidly progressive encephalopathy (brain dysfunction) and fatty degeneration of the liver.

The exact cause of Reye Syndrome remains unknown, but it has been linked to the use of aspirin and other salicylate-containing medications during viral illnesses. The American Academy of Pediatrics recommends avoiding the use of aspirin in children and teenagers with chickenpox or flu-like symptoms due to this association.

Early symptoms of Reye Syndrome include persistent vomiting, diarrhea, and listlessness. As the condition progresses, symptoms can worsen and may include disorientation, seizures, coma, and even death in severe cases. Diagnosis is typically based on clinical presentation, laboratory tests, and sometimes a liver biopsy.

Treatment for Reye Syndrome involves supportive care, such as fluid and electrolyte management, addressing metabolic abnormalities, controlling intracranial pressure, and providing ventilatory support if necessary. Early recognition and intervention are crucial to improving outcomes in affected individuals.

Fasting is defined in medical terms as the abstinence from food or drink for a period of time. This practice is often recommended before certain medical tests or procedures, as it helps to ensure that the results are not affected by recent eating or drinking.

In some cases, fasting may also be used as a therapeutic intervention, such as in the management of seizures or other neurological conditions. Fasting can help to lower blood sugar and insulin levels, which can have a variety of health benefits. However, it is important to note that prolonged fasting can also have negative effects on the body, including malnutrition, dehydration, and electrolyte imbalances.

Fasting is also a spiritual practice in many religions, including Christianity, Islam, Buddhism, and Hinduism. In these contexts, fasting is often seen as a way to purify the mind and body, to focus on spiritual practices, or to express devotion or mourning.

Glucose is a simple monosaccharide (or single sugar) that serves as the primary source of energy for living organisms. It's a fundamental molecule in biology, often referred to as "dextrose" or "grape sugar." Glucose has the molecular formula C6H12O6 and is vital to the functioning of cells, especially those in the brain and nervous system.

In the body, glucose is derived from the digestion of carbohydrates in food, and it's transported around the body via the bloodstream to cells where it can be used for energy. Cells convert glucose into a usable form through a process called cellular respiration, which involves a series of metabolic reactions that generate adenosine triphosphate (ATP)—the main currency of energy in cells.

Glucose is also stored in the liver and muscles as glycogen, a polysaccharide (multiple sugar) that can be broken down back into glucose when needed for energy between meals or during physical activity. Maintaining appropriate blood glucose levels is crucial for overall health, and imbalances can lead to conditions such as diabetes mellitus.

Inhibitory Concentration 50 (IC50) is a measure used in pharmacology, toxicology, and virology to describe the potency of a drug or chemical compound. It refers to the concentration needed to reduce the biological or biochemical activity of a given substance by half. Specifically, it is most commonly used in reference to the inhibition of an enzyme or receptor.

In the context of infectious diseases, IC50 values are often used to compare the effectiveness of antiviral drugs against a particular virus. A lower IC50 value indicates that less of the drug is needed to achieve the desired effect, suggesting greater potency and potentially fewer side effects. Conversely, a higher IC50 value suggests that more of the drug is required to achieve the same effect, indicating lower potency.

It's important to note that IC50 values can vary depending on the specific assay or experimental conditions used, so they should be interpreted with caution and in conjunction with other measures of drug efficacy.

Insulin is a hormone produced by the beta cells of the pancreatic islets, primarily in response to elevated levels of glucose in the circulating blood. It plays a crucial role in regulating blood glucose levels and facilitating the uptake and utilization of glucose by peripheral tissues, such as muscle and adipose tissue, for energy production and storage. Insulin also inhibits glucose production in the liver and promotes the storage of excess glucose as glycogen or triglycerides.

Deficiency in insulin secretion or action leads to impaired glucose regulation and can result in conditions such as diabetes mellitus, characterized by chronic hyperglycemia and associated complications. Exogenous insulin is used as a replacement therapy in individuals with diabetes to help manage their blood glucose levels and prevent long-term complications.

A diet, in medical terms, refers to the planned and regular consumption of food and drinks. It is a balanced selection of nutrient-rich foods that an individual eats on a daily or periodic basis to meet their energy needs and maintain good health. A well-balanced diet typically includes a variety of fruits, vegetables, whole grains, lean proteins, and low-fat dairy products.

A diet may also be prescribed for therapeutic purposes, such as in the management of certain medical conditions like diabetes, hypertension, or obesity. In these cases, a healthcare professional may recommend specific restrictions or modifications to an individual's regular diet to help manage their condition and improve their overall health.

It is important to note that a healthy and balanced diet should be tailored to an individual's age, gender, body size, activity level, and any underlying medical conditions. Consulting with a healthcare professional, such as a registered dietitian or nutritionist, can help ensure that an individual's dietary needs are being met in a safe and effective way.

Adipose tissue, brown, also known as brown adipose tissue (BAT), is a type of fat in mammals that plays a crucial role in non-shivering thermogenesis, which is the process of generating heat and maintaining body temperature through the burning of calories. Unlike white adipose tissue, which primarily stores energy in the form of lipids, brown adipose tissue contains numerous mitochondria rich in iron, giving it a brown appearance. These mitochondria contain a protein called uncoupling protein 1 (UCP1), which allows for the efficient conversion of stored energy into heat rather than ATP production.

Brown adipose tissue is typically found in newborns and hibernating animals, but recent studies have shown that adults also possess functional brown adipose tissue, particularly around the neck, shoulders, and spine. The activation of brown adipose tissue has been suggested as a potential strategy for combating obesity and related metabolic disorders due to its ability to burn calories and increase energy expenditure. However, further research is needed to fully understand the mechanisms underlying brown adipose tissue function and its therapeutic potential in treating these conditions.

Glucagon is a hormone produced by the alpha cells of the pancreas. Its main function is to regulate glucose levels in the blood by stimulating the liver to convert stored glycogen into glucose, which can then be released into the bloodstream. This process helps to raise blood sugar levels when they are too low, such as during hypoglycemia.

Glucagon is a 29-amino acid polypeptide that is derived from the preproglucagon protein. It works by binding to glucagon receptors on liver cells, which triggers a series of intracellular signaling events that lead to the activation of enzymes involved in glycogen breakdown.

In addition to its role in glucose regulation, glucagon has also been shown to have other physiological effects, such as promoting lipolysis (the breakdown of fat) and inhibiting gastric acid secretion. Glucagon is often used clinically in the treatment of hypoglycemia, as well as in diagnostic tests to assess pancreatic function.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

Lipids are a broad group of organic compounds that are insoluble in water but soluble in nonpolar organic solvents. They include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E, and K), monoglycerides, diglycerides, triglycerides, and phospholipids. Lipids serve many important functions in the body, including energy storage, acting as structural components of cell membranes, and serving as signaling molecules. High levels of certain lipids, particularly cholesterol and triglycerides, in the blood are associated with an increased risk of cardiovascular disease.

Cytoplasmic receptors and nuclear receptors are two types of intracellular receptors that play crucial roles in signal transduction pathways and regulation of gene expression. They are classified based on their location within the cell. Here are the medical definitions for each:

1. Cytoplasmic Receptors: These are a group of intracellular receptors primarily found in the cytoplasm of cells, which bind to specific hormones, growth factors, or other signaling molecules. Upon binding, these receptors undergo conformational changes that allow them to interact with various partners, such as adapter proteins and enzymes, leading to activation of downstream signaling cascades. These pathways ultimately result in modulation of cellular processes like proliferation, differentiation, and apoptosis. Examples of cytoplasmic receptors include receptor tyrosine kinases (RTKs), serine/threonine kinase receptors, and cytokine receptors.
2. Nuclear Receptors: These are a distinct class of intracellular receptors that reside primarily in the nucleus of cells. They bind to specific ligands, such as steroid hormones, thyroid hormones, vitamin D, retinoic acid, and various other lipophilic molecules. Upon binding, nuclear receptors undergo conformational changes that facilitate their interaction with co-regulatory proteins and the DNA. This interaction results in the modulation of gene transcription, ultimately leading to alterations in protein expression and cellular responses. Examples of nuclear receptors include estrogen receptor (ER), androgen receptor (AR), glucocorticoid receptor (GR), thyroid hormone receptor (TR), vitamin D receptor (VDR), and peroxisome proliferator-activated receptors (PPARs).

Both cytoplasmic and nuclear receptors are essential components of cellular communication networks, allowing cells to respond appropriately to extracellular signals and maintain homeostasis. Dysregulation of these receptors has been implicated in various diseases, including cancer, diabetes, and autoimmune disorders.

Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:

1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction

Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:

1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.

Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).

Glucosides are chemical compounds that consist of a glycosidic bond between a sugar molecule (typically glucose) and another non-sugar molecule, which can be an alcohol, phenol, or steroid. They occur naturally in various plants and some microorganisms.

Glucosides are not medical terms per se, but they do have significance in pharmacology and toxicology because some of them may release the sugar portion upon hydrolysis, yielding aglycone, which can have physiological effects when ingested or absorbed into the body. Some glucosides are used as medications or dietary supplements due to their therapeutic properties, while others can be toxic if consumed in large quantities.

Fatty acid synthases (FAS) are a group of enzymes that are responsible for the synthesis of fatty acids in the body. They catalyze a series of reactions that convert acetyl-CoA and malonyl-CoA into longer chain fatty acids, which are then used for various purposes such as energy storage or membrane formation.

The human genome encodes two types of FAS: type I and type II. Type I FAS is a large multifunctional enzyme complex found in the cytoplasm of cells, while type II FAS consists of individual enzymes located in the mitochondria. Both types of FAS play important roles in lipid metabolism, but their regulation and expression differ depending on the tissue and physiological conditions.

Inhibition of FAS has been explored as a potential therapeutic strategy for various diseases, including cancer, obesity, and metabolic disorders. However, more research is needed to fully understand the complex mechanisms regulating FAS activity and its role in human health and disease.

Gene expression is the process by which the information encoded in a gene is used to synthesize a functional gene product, such as a protein or RNA molecule. This process involves several steps: transcription, RNA processing, and translation. During transcription, the genetic information in DNA is copied into a complementary RNA molecule, known as messenger RNA (mRNA). The mRNA then undergoes RNA processing, which includes adding a cap and tail to the mRNA and splicing out non-coding regions called introns. The resulting mature mRNA is then translated into a protein on ribosomes in the cytoplasm through the process of translation.

The regulation of gene expression is a complex and highly controlled process that allows cells to respond to changes in their environment, such as growth factors, hormones, and stress signals. This regulation can occur at various stages of gene expression, including transcriptional activation or repression, RNA processing, mRNA stability, and translation. Dysregulation of gene expression has been implicated in many diseases, including cancer, genetic disorders, and neurological conditions.

Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).

Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.

Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.

Genetic transcription is the process by which the information in a strand of DNA is used to create a complementary RNA molecule. This process is the first step in gene expression, where the genetic code in DNA is converted into a form that can be used to produce proteins or functional RNAs.

During transcription, an enzyme called RNA polymerase binds to the DNA template strand and reads the sequence of nucleotide bases. As it moves along the template, it adds complementary RNA nucleotides to the growing RNA chain, creating a single-stranded RNA molecule that is complementary to the DNA template strand. Once transcription is complete, the RNA molecule may undergo further processing before it can be translated into protein or perform its functional role in the cell.

Transcription can be either "constitutive" or "regulated." Constitutive transcription occurs at a relatively constant rate and produces essential proteins that are required for basic cellular functions. Regulated transcription, on the other hand, is subject to control by various intracellular and extracellular signals, allowing cells to respond to changing environmental conditions or developmental cues.

Hyperammonemia is a medical condition characterized by an excessively high level of ammonia (a toxic byproduct of protein metabolism) in the blood. This can lead to serious neurological symptoms and complications, as ammonia is highly toxic to the brain. Hyperammonemia can be caused by various underlying conditions, including liver disease, genetic disorders that affect ammonia metabolism, certain medications, and infections. It is important to diagnose and treat hyperammonemia promptly to prevent long-term neurological damage or even death. Treatment typically involves addressing the underlying cause of the condition, as well as providing supportive care such as administering medications that help remove ammonia from the blood.

Subtilisins are a group of serine proteases that are produced by certain bacteria, including Bacillus subtilis. They are named after the bacterium and the Latin word "subtilis," which means delicate or finely made. Subtilisins are alkaline proteases, meaning they work best in slightly basic conditions.

Subtilisins have a broad specificity for cleaving peptide bonds and can hydrolyze a wide range of protein substrates. They are widely used in industry for various applications such as detergents, food processing, leather treatment, and biotechnology due to their ability to function at high temperatures and in the presence of denaturing agents.

In medicine, subtilisins have been studied for their potential use in therapeutic applications, including as anti-inflammatory agents and in wound healing. However, more research is needed to fully understand their mechanisms of action and potential benefits.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

Dietary fats, also known as fatty acids, are a major nutrient that the body needs for energy and various functions. They are an essential component of cell membranes and hormones, and they help the body absorb certain vitamins. There are several types of dietary fats:

1. Saturated fats: These are typically solid at room temperature and are found in animal products such as meat, butter, and cheese, as well as tropical oils like coconut and palm oil. Consuming a high amount of saturated fats can raise levels of unhealthy LDL cholesterol and increase the risk of heart disease.
2. Unsaturated fats: These are typically liquid at room temperature and can be further divided into monounsaturated and polyunsaturated fats. Monounsaturated fats, found in foods such as olive oil, avocados, and nuts, can help lower levels of unhealthy LDL cholesterol while maintaining levels of healthy HDL cholesterol. Polyunsaturated fats, found in foods such as fatty fish, flaxseeds, and walnuts, have similar effects on cholesterol levels and also provide essential omega-3 and omega-6 fatty acids that the body cannot produce on its own.
3. Trans fats: These are unsaturated fats that have been chemically modified to be solid at room temperature. They are often found in processed foods such as baked goods, fried foods, and snack foods. Consuming trans fats can raise levels of unhealthy LDL cholesterol and lower levels of healthy HDL cholesterol, increasing the risk of heart disease.

It is recommended to limit intake of saturated and trans fats and to consume more unsaturated fats as part of a healthy diet.

Cell fractionation is a laboratory technique used to separate different cellular components or organelles based on their size, density, and other physical properties. This process involves breaking open the cell (usually through homogenization), and then separating the various components using various methods such as centrifugation, filtration, and ultracentrifugation.

The resulting fractions can include the cytoplasm, mitochondria, nuclei, endoplasmic reticulum, Golgi apparatus, lysosomes, peroxisomes, and other organelles. Each fraction can then be analyzed separately to study the biochemical and functional properties of the individual components.

Cell fractionation is a valuable tool in cell biology research, allowing scientists to study the structure, function, and interactions of various cellular components in a more detailed and precise manner.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

Organ specificity, in the context of immunology and toxicology, refers to the phenomenon where a substance (such as a drug or toxin) or an immune response primarily affects certain organs or tissues in the body. This can occur due to various reasons such as:

1. The presence of specific targets (like antigens in the case of an immune response or receptors in the case of drugs) that are more abundant in these organs.
2. The unique properties of certain cells or tissues that make them more susceptible to damage.
3. The way a substance is metabolized or cleared from the body, which can concentrate it in specific organs.

For example, in autoimmune diseases, organ specificity describes immune responses that are directed against antigens found only in certain organs, such as the thyroid gland in Hashimoto's disease. Similarly, some toxins or drugs may have a particular affinity for liver cells, leading to liver damage or specific drug interactions.

Site-directed mutagenesis is a molecular biology technique used to introduce specific and targeted changes to a specific DNA sequence. This process involves creating a new variant of a gene or a specific region of interest within a DNA molecule by introducing a planned, deliberate change, or mutation, at a predetermined site within the DNA sequence.

The methodology typically involves the use of molecular tools such as PCR (polymerase chain reaction), restriction enzymes, and/or ligases to introduce the desired mutation(s) into a plasmid or other vector containing the target DNA sequence. The resulting modified DNA molecule can then be used to transform host cells, allowing for the production of large quantities of the mutated gene or protein for further study.

Site-directed mutagenesis is a valuable tool in basic research, drug discovery, and biotechnology applications where specific changes to a DNA sequence are required to understand gene function, investigate protein structure/function relationships, or engineer novel biological properties into existing genes or proteins.

Cricetinae is a subfamily of rodents that includes hamsters, gerbils, and relatives. These small mammals are characterized by having short limbs, compact bodies, and cheek pouches for storing food. They are native to various parts of the world, particularly in Europe, Asia, and Africa. Some species are popular pets due to their small size, easy care, and friendly nature. In a medical context, understanding the biology and behavior of Cricetinae species can be important for individuals who keep them as pets or for researchers studying their physiology.

A cell membrane, also known as the plasma membrane, is a thin semi-permeable phospholipid bilayer that surrounds all cells in animals, plants, and microorganisms. It functions as a barrier to control the movement of substances in and out of the cell, allowing necessary molecules such as nutrients, oxygen, and signaling molecules to enter while keeping out harmful substances and waste products. The cell membrane is composed mainly of phospholipids, which have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails. This unique structure allows the membrane to be flexible and fluid, yet selectively permeable. Additionally, various proteins are embedded in the membrane that serve as channels, pumps, receptors, and enzymes, contributing to the cell's overall functionality and communication with its environment.

Histidine is an essential amino acid, meaning it cannot be synthesized by the human body and must be obtained through dietary sources. Its chemical formula is C6H9N3O2. Histidine plays a crucial role in several physiological processes, including:

1. Protein synthesis: As an essential amino acid, histidine is required for the production of proteins, which are vital components of various tissues and organs in the body.

2. Hemoglobin synthesis: Histidine is a key component of hemoglobin, the protein in red blood cells responsible for carrying oxygen throughout the body. The imidazole side chain of histidine acts as a proton acceptor/donor, facilitating the release and uptake of oxygen by hemoglobin.

3. Acid-base balance: Histidine is involved in maintaining acid-base homeostasis through its role in the biosynthesis of histamine, which is a critical mediator of inflammatory responses and allergies. The decarboxylation of histidine results in the formation of histamine, which can increase vascular permeability and modulate immune responses.

4. Metal ion binding: Histidine has a high affinity for metal ions such as zinc, copper, and iron. This property allows histidine to participate in various enzymatic reactions and maintain the structural integrity of proteins.

5. Antioxidant defense: Histidine-containing dipeptides, like carnosine and anserine, have been shown to exhibit antioxidant properties by scavenging reactive oxygen species (ROS) and chelating metal ions. These compounds may contribute to the protection of proteins and DNA from oxidative damage.

Dietary sources of histidine include meat, poultry, fish, dairy products, and wheat germ. Histidine deficiency is rare but can lead to growth retardation, anemia, and impaired immune function.

Methylhydrazines are a class of organic compounds that contain a hydrazine functional group with one or more methyl substituents. Hydrazine is a simple inorganic compound with the formula N2H4, and it consists of a nitrogen atom bonded to four hydrogen atoms through nitrogen-hydrogen covalent bonds. When one or more of these hydrogens are replaced by a methyl group (CH3), we get methylhydrazines.

The most common methylhydrazine is monomethylhydrazine (MMH), which has the molecular formula CH6N2. It is an colorless, oily liquid with an ammonia-like odor and is highly toxic and reactive. MMH is used as a rocket propellant due to its high specific impulse and density.

Another example of methylhydrazine is unsymmetrical dimethylhydrazine (UDMH), which has the molecular formula C2H8N2. UDMH is also a colorless, oily liquid with an ammonia-like odor and is used as a rocket propellant.

It's important to note that methylhydrazines are highly toxic and reactive compounds, and they require careful handling and storage. They can cause harm to the skin, eyes, respiratory system, and nervous system, and prolonged exposure can lead to serious health effects or death.

"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.

Mersalyl is not a medical condition or diagnosis, but rather a pharmaceutical compound. It is a type of organic mercurial salt that was historically used in medicine as a diuretic and an antimicrobial agent. However, its use has been largely discontinued due to the toxic effects of mercury on the human body. Therefore, there isn't a medical definition for 'Mersalyl'.

Tertiary protein structure refers to the three-dimensional arrangement of all the elements (polypeptide chains) of a single protein molecule. It is the highest level of structural organization and results from interactions between various side chains (R groups) of the amino acids that make up the protein. These interactions, which include hydrogen bonds, ionic bonds, van der Waals forces, and disulfide bridges, give the protein its unique shape and stability, which in turn determines its function. The tertiary structure of a protein can be stabilized by various factors such as temperature, pH, and the presence of certain ions. Any changes in these factors can lead to denaturation, where the protein loses its tertiary structure and thus its function.

Mitochondrial proteins are any proteins that are encoded by the nuclear genome or mitochondrial genome and are located within the mitochondria, an organelle found in eukaryotic cells. These proteins play crucial roles in various cellular processes including energy production, metabolism of lipids, amino acids, and steroids, regulation of calcium homeostasis, and programmed cell death or apoptosis.

Mitochondrial proteins can be classified into two main categories based on their origin:

1. Nuclear-encoded mitochondrial proteins (NEMPs): These are proteins that are encoded by genes located in the nucleus, synthesized in the cytoplasm, and then imported into the mitochondria through specific import pathways. NEMPs make up about 99% of all mitochondrial proteins and are involved in various functions such as oxidative phosphorylation, tricarboxylic acid (TCA) cycle, fatty acid oxidation, and mitochondrial dynamics.

2. Mitochondrial DNA-encoded proteins (MEPs): These are proteins that are encoded by the mitochondrial genome, synthesized within the mitochondria, and play essential roles in the electron transport chain (ETC), a key component of oxidative phosphorylation. The human mitochondrial genome encodes only 13 proteins, all of which are subunits of complexes I, III, IV, and V of the ETC.

Defects in mitochondrial proteins can lead to various mitochondrial disorders, which often manifest as neurological, muscular, or metabolic symptoms due to impaired energy production. These disorders are usually caused by mutations in either nuclear or mitochondrial genes that encode mitochondrial proteins.

Fatty liver, also known as hepatic steatosis, is a medical condition characterized by the abnormal accumulation of fat in the liver. The liver's primary function is to process nutrients, filter blood, and fight infections, among other tasks. When excess fat builds up in the liver cells, it can impair liver function and lead to inflammation, scarring, and even liver failure if left untreated.

Fatty liver can be caused by various factors, including alcohol consumption, obesity, nonalcoholic fatty liver disease (NAFLD), viral hepatitis, and certain medications or medical conditions. NAFLD is the most common cause of fatty liver in the United States and other developed countries, affecting up to 25% of the population.

Symptoms of fatty liver may include fatigue, weakness, weight loss, loss of appetite, nausea, abdominal pain or discomfort, and jaundice (yellowing of the skin and eyes). However, many people with fatty liver do not experience any symptoms, making it essential to diagnose and manage the condition through regular check-ups and blood tests.

Treatment for fatty liver depends on the underlying cause. Lifestyle changes such as weight loss, exercise, and dietary modifications are often recommended for people with NAFLD or alcohol-related fatty liver disease. Medications may also be prescribed to manage related conditions such as diabetes, high cholesterol, or metabolic syndrome. In severe cases of liver damage, a liver transplant may be necessary.

'Gene expression regulation' refers to the processes that control whether, when, and where a particular gene is expressed, meaning the production of a specific protein or functional RNA encoded by that gene. This complex mechanism can be influenced by various factors such as transcription factors, chromatin remodeling, DNA methylation, non-coding RNAs, and post-transcriptional modifications, among others. Proper regulation of gene expression is crucial for normal cellular function, development, and maintaining homeostasis in living organisms. Dysregulation of gene expression can lead to various diseases, including cancer and genetic disorders.

Alanine is an alpha-amino acid that is used in the biosynthesis of proteins. The molecular formula for alanine is C3H7NO2. It is a non-essential amino acid, which means that it can be produced by the human body through the conversion of other nutrients, such as pyruvate, and does not need to be obtained directly from the diet.

Alanine is classified as an aliphatic amino acid because it contains a simple carbon side chain. It is also a non-polar amino acid, which means that it is hydrophobic and tends to repel water. Alanine plays a role in the metabolism of glucose and helps to regulate blood sugar levels. It is also involved in the transfer of nitrogen between tissues and helps to maintain the balance of nitrogen in the body.

In addition to its role as a building block of proteins, alanine is also used as a neurotransmitter in the brain and has been shown to have a calming effect on the nervous system. It is found in many foods, including meats, poultry, fish, eggs, dairy products, and legumes.

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