The origin of life. It includes studies of the potential basis for life in organic compounds but excludes studies of the development of altered forms of life through mutation and natural selection, which is BIOLOGICAL EVOLUTION.
The cellular processes involved in adjustments to the MITOCHONDRIAL VOLUME, content, and activity, that depend on the energy demands of the cell.
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)
An endoribonuclease that is specific for double-stranded RNA. It plays a role in POST-TRANSCRIPTIONAL RNA PROCESSING of pre-RIBOSOMAL RNA and a variety of other RNA structures that contain double-stranded regions.
Proteins encoded by the mitochondrial genome or proteins encoded by the nuclear genome that are imported to and resident in the MITOCHONDRIA.
Microbodies which occur in animal and plant cells and in certain fungi and protozoa. They contain peroxidase, catalase, and allied enzymes. (From Singleton and Sainsbury, Dictionary of Microbiology and Molecular Biology, 2nd ed)
A transcription factor that controls the expression of variety of proteins including CYTOCHROME C and 5-AMINOLEVULINATE SYNTHETASE. It plays an important role in maintenance of the RESPIRATORY CHAIN of MITOCHONDRIA.
Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.
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.
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.
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.
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.
Multicomponent ribonucleoprotein structures found in the CYTOPLASM of all cells, and in MITOCHONDRIA, and PLASTIDS. They function in PROTEIN BIOSYNTHESIS via GENETIC TRANSLATION.
Within most types of eukaryotic CELL NUCLEUS, a distinct region, not delimited by a membrane, in which some species of rRNA (RNA, RIBOSOMAL) are synthesized and assembled into ribonucleoprotein subunits of ribosomes. In the nucleolus rRNA is transcribed from a nucleolar organizer, i.e., a group of tandemly repeated chromosomal genes which encode rRNA and which are transcribed by RNA polymerase I. (Singleton & Sainsbury, Dictionary of Microbiology & Molecular Biology, 2d ed)
The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.
Post-transcriptional biological modification of messenger, transfer, or ribosomal RNAs or their precursors. It includes cleavage, methylation, thiolation, isopentenylation, pseudouridine formation, conformational changes, and association with ribosomal protein.
A heterogeneous group of inherited metabolic disorders marked by absent or dysfunctional PEROXISOMES. Peroxisomal enzymatic abnormalities may be single or multiple. Biosynthetic peroxisomal pathways are compromised, including the ability to synthesize ether lipids and to oxidize long-chain fatty acid precursors. Diseases in this category include ZELLWEGER SYNDROME; INFANTILE REFSUM DISEASE; rhizomelic chondrodysplasia (CHONDRODYSPLASIA PUNCTATA, RHIZOMELIC); hyperpipecolic acidemia; neonatal adrenoleukodystrophy; and ADRENOLEUKODYSTROPHY (X-linked). Neurologic dysfunction is a prominent feature of most peroxisomal disorders.
The large subunit of the 80s ribosome of eukaryotes. It is composed of the 28S RIBOSOMAL RNA, the 5.8S RIBOSOMAL RNA, the 5S RIBOSOMAL RNA, and about 50 different RIBOSOMAL PROTEINS.
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.
Small double-stranded, non-protein coding RNAs, 21-25 nucleotides in length generated from single-stranded microRNA gene transcripts by the same RIBONUCLEASE III, Dicer, that produces small interfering RNAs (RNA, SMALL INTERFERING). They become part of the RNA-INDUCED SILENCING COMPLEX and repress the translation (TRANSLATION, GENETIC) of target RNA by binding to homologous 3'UTR region as an imperfect match. The small temporal RNAs (stRNAs), let-7 and lin-4, from C. elegans, are the first 2 miRNAs discovered, and are from a class of miRNAs involved in developmental timing.
The most abundant form of RNA. Together with proteins, it forms the ribosomes, playing a structural role and also a role in ribosomal binding of mRNA and tRNAs. Individual chains are conventionally designated by their sedimentation coefficients. In eukaryotes, four large chains exist, synthesized in the nucleolus and constituting about 50% of the ribosome. (Dorland, 28th ed)
A basic-leucine zipper transcription factor that is involved in regulating inflammatory responses, MORPHOGENESIS, and HEME biosynthesis.
Specific particles of membrane-bound organized living substances present in eukaryotic cells, such as the MITOCHONDRIA; the GOLGI APPARATUS; ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
Mitochondria of skeletal and smooth muscle. It does not include myocardial mitochondria for which MITOCHONDRIA, HEART is available.
RNA transcripts of the DNA that are in some unfinished stage of post-transcriptional processing (RNA PROCESSING, POST-TRANSCRIPTIONAL) required for function. RNA precursors may undergo several steps of RNA SPLICING during which the phosphodiester bonds at exon-intron boundaries are cleaved and the introns are excised. Consequently a new bond is formed between the ends of the exons. Resulting mature RNAs can then be used; for example, mature mRNA (RNA, MESSENGER) is used as a template for protein production.
Syndrome characterized by the triad of oculocutaneous albinism (ALBINISM, OCULOCUTANEOUS); PLATELET STORAGE POOL DEFICIENCY; and lysosomal accumulation of ceroid lipofuscin.
Proteins that bind to RNA molecules. Included here are RIBONUCLEOPROTEINS and other proteins whose function is to bind specifically to RNA.
Double-stranded DNA of MITOCHONDRIA. In eukaryotes, the mitochondrial GENOME is circular and codes for ribosomal RNAs, transfer RNAs, and about 10 proteins.
Melanin-containing organelles found in melanocytes and melanophores.
Proteins found in ribosomes. They are believed to have a catalytic function in reconstituting biologically active ribosomal subunits.
A family of RNA-binding proteins that has specificity for MICRORNAS and SMALL INTERFERING RNA molecules. The proteins take part in RNA processing events as core components of RNA-induced silencing complex.
Thin, hairlike appendages, 1 to 20 microns in length and often occurring in large numbers, present on the cells of gram-negative bacteria, particularly Enterobacteriaceae and Neisseria. Unlike flagella, they do not possess motility, but being protein (pilin) in nature, they possess antigenic and hemagglutinating properties. They are of medical importance because some fimbriae mediate the attachment of bacteria to cells via adhesins (ADHESINS, BACTERIAL). Bacterial fimbriae refer to common pili, to be distinguished from the preferred use of "pili", which is confined to sex pili (PILI, SEX).
An autosomal recessive disorder due to defects in PEROXISOME biogenesis which involves more than 13 genes encoding peroxin proteins of the peroxisomal membrane and matrix. Zellweger syndrome is typically seen in the neonatal period with features such as dysmorphic skull; MUSCLE HYPOTONIA; SENSORINEURAL HEARING LOSS; visual compromise; SEIZURES; progressive degeneration of the KIDNEYS and the LIVER. Zellweger-like syndrome refers to phenotypes resembling the neonatal Zellweger syndrome but seen in children or adults with apparently intact peroxisome biogenesis.
A family of transcription factors that control expression of a variety of nuclear GENES encoding proteins that function in the RESPIRATORY CHAIN of the MITOCHONDRIA.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
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.
A gene silencing phenomenon whereby specific dsRNAs (RNA, DOUBLE-STRANDED) trigger the degradation of homologous mRNA (RNA, MESSENGER). The specific dsRNAs are processed into SMALL INTERFERING RNA (siRNA) which serves as a guide for cleavage of the homologous mRNA in the RNA-INDUCED SILENCING COMPLEX. DNA METHYLATION may also be triggered during this process.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.
A family of cellular proteins that mediate the correct assembly or disassembly of polypeptides and their associated ligands. Although they take part in the assembly process, molecular chaperones are not components of the final structures.
Small double-stranded, non-protein coding RNAs (21-31 nucleotides) involved in GENE SILENCING functions, especially RNA INTERFERENCE (RNAi). Endogenously, siRNAs are generated from dsRNAs (RNA, DOUBLE-STRANDED) by the same ribonuclease, Dicer, that generates miRNAs (MICRORNAS). The perfect match of the siRNAs' antisense strand to their target RNAs mediates RNAi by siRNA-guided RNA cleavage. siRNAs fall into different classes including trans-acting siRNA (tasiRNA), repeat-associated RNA (rasiRNA), small-scan RNA (scnRNA), and Piwi protein-interacting RNA (piRNA) and have different specific gene silencing functions.
Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
A system of cisternae in the CYTOPLASM of many cells. In places the endoplasmic reticulum is continuous with the plasma membrane (CELL MEMBRANE) or outer membrane of the nuclear envelope. If the outer surfaces of the endoplasmic reticulum membranes are coated with ribosomes, the endoplasmic reticulum is said to be rough-surfaced (ENDOPLASMIC RETICULUM, ROUGH); otherwise it is said to be smooth-surfaced (ENDOPLASMIC RETICULUM, SMOOTH). (King & Stansfield, A Dictionary of Genetics, 4th ed)
Proteins that are structural components of bacterial fimbriae (FIMBRIAE, BACTERIAL) or sex pili (PILI, SEX).
A large family of RNA helicases that share a common protein motif with the single letter amino acid sequence D-E-A-D (Asp-Glu-Ala-Asp). In addition to RNA helicase activity, members of the DEAD-box family participate in other aspects of RNA metabolism and regulation of RNA function.
A multisubunit enzyme complex containing CYTOCHROME A GROUP; CYTOCHROME A3; two copper atoms; and 13 different protein subunits. It is the terminal oxidase complex of the RESPIRATORY CHAIN and collects electrons that are transferred from the reduced CYTOCHROME C GROUP and donates them to molecular OXYGEN, which is then reduced to water. The redox reaction is simultaneously coupled to the transport of PROTONS across the inner mitochondrial membrane.
Proteins found in any species of bacterium.
Proteins found in the nucleus of a cell. Do not confuse with NUCLEOPROTEINS which are proteins conjugated with nucleic acids, that are not necessarily present in the nucleus.
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.
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.
Proteins that originate from plants species belonging to the genus ARABIDOPSIS. The most intensely studied species of Arabidopsis, Arabidopsis thaliana, is commonly used in laboratory experiments.
A plant genus of the family BRASSICACEAE that contains ARABIDOPSIS PROTEINS and MADS DOMAIN PROTEINS. The species A. thaliana is used for experiments in classical plant genetics as well as molecular genetic studies in plant physiology, biochemistry, and development.
Plant cell inclusion bodies that contain the photosynthetic pigment CHLOROPHYLL, which is associated with the membrane of THYLAKOIDS. Chloroplasts occur in cells of leaves and young stems of plants. They are also found in some forms of PHYTOPLANKTON such as HAPTOPHYTA; DINOFLAGELLATES; DIATOMS; and CRYPTOPHYTA.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Highly conserved nuclear RNA-protein complexes that function in RNA processing in the nucleus, including pre-mRNA splicing and pre-mRNA 3'-end processing in the nucleoplasm, and pre-rRNA processing in the nucleolus (see RIBONUCLEOPROTEINS, SMALL NUCLEOLAR).
A stack of flattened vesicles that functions in posttranslational processing and sorting of proteins, receiving them from the rough ENDOPLASMIC RETICULUM and directing them to secretory vesicles, LYSOSOMES, or the CELL MEMBRANE. The movement of proteins takes place by transfer vesicles that bud off from the rough endoplasmic reticulum or Golgi apparatus and fuse with the Golgi, lysosomes or cell membrane. (From Glick, Glossary of Biochemistry and Molecular Biology, 1990)
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
Membrane-bound cytoplasmic vesicles formed by invagination of phagocytized material. They fuse with lysosomes to form phagolysosomes in which the hydrolytic enzymes of the lysosome digest the phagocytized material.
The quantity of volume or surface area of ORGANELLES.
The small subunit of the 80s ribosome of eukaryotes. It is composed of the 18S RIBOSOMAL RNA and 32 different RIBOSOMAL PROTEINS.
Transport proteins that carry specific substances in the blood or across cell membranes.
Nucleolar RNA-protein complexes that function in pre-ribosomal RNA processing.
A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.
Any spaces or cavities within a cell. They may function in digestion, storage, secretion, or excretion.
Constituent of the 40S subunit of eukaryotic ribosomes. 18S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.
Proteins found in any species of fungus.
The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.
A class of morphologically heterogeneous cytoplasmic particles in animal and plant tissues characterized by their content of hydrolytic enzymes and the structure-linked latency of these enzymes. The intracellular functions of lysosomes depend on their lytic potential. The single unit membrane of the lysosome acts as a barrier between the enzymes enclosed in the lysosome and the external substrate. The activity of the enzymes contained in lysosomes is limited or nil unless the vesicle in which they are enclosed is ruptured. Such rupture is supposed to be under metabolic (hormonal) control. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
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.
Proteins obtained from ESCHERICHIA COLI.
A genetic rearrangement through loss of segments of DNA or RNA, bringing sequences which are normally separated into close proximity. This deletion may be detected using cytogenetic techniques and can also be inferred from the phenotype, indicating a deletion at one specific locus.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
Electron-dense cytoplasmic particles bounded by a single membrane, such as PEROXISOMES; GLYOXYSOMES; and glycosomes.
Established cell cultures that have the potential to propagate indefinitely.
Small nuclear RNAs that are involved in the processing of pre-ribosomal RNA in the nucleolus. Box C/D containing snoRNAs (U14, U15, U16, U20, U21 and U24-U63) direct site-specific methylation of various ribose moieties. Box H/ACA containing snoRNAs (E2, E3, U19, U23, and U64-U72) direct the conversion of specific uridines to pseudouridine. Site-specific cleavages resulting in the mature ribosomal RNAs are directed by snoRNAs U3, U8, U14, U22 and the snoRNA components of RNase MRP and RNase P.
The quantity of volume or surface area of MITOCHONDRIA.
The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.
The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.
Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.
Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Ribonucleic acid in plants having regulatory and catalytic roles as well as involvement in protein synthesis.
Endosomes containing intraluminal vesicles which are formed by the inward budding of the endosome membrane. Multivesicular bodies (MVBs) may fuse with other organelles such as LYSOSOMES or fuse back with the PLASMA MEMBRANE releasing their contents by EXOCYTOSIS. The MVB intraluminal vesicles released into the extracellular environment are known as EXOSOMES.
A distinct subnuclear domain enriched in splicesomal snRNPs (RIBONUCLEOPROTEINS, SMALL NUCLEAR) and p80-coilin.
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).
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Cytoplasmic vesicles formed when COATED VESICLES shed their CLATHRIN coat. Endosomes internalize macromolecules bound by receptors on the cell surface.
Macromolecular complexes formed from the association of defined protein subunits.
Electron microscopy in which the ELECTRONS or their reaction products that pass down through the specimen are imaged below the plane of the specimen.
The metabolic process of all living cells (animal and plant) in which oxygen is used to provide a source of energy for the cell.
Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
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.
Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.
Ribonucleic acid in fungi having regulatory and catalytic roles as well as involvement in protein synthesis.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in plants.
Vesicles derived from the GOLGI APPARATUS containing material to be released at the cell surface.
Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
Single chains of amino acids that are the units of multimeric PROTEINS. Multimeric proteins can be composed of identical or non-identical subunits. One or more monomeric subunits may compose a protomer which itself is a subunit structure of a larger assembly.
A broad category of proteins involved in the formation, transport and dissolution of TRANSPORT VESICLES. They play a role in the intracellular transport of molecules contained within membrane vesicles. Vesicular transport proteins are distinguished from MEMBRANE TRANSPORT PROTEINS, which move molecules across membranes, by the mode in which the molecules are transported.
Membranous cisternae of the CHLOROPLAST containing photosynthetic pigments, reaction centers, and the electron-transport chain. Each thylakoid consists of a flattened sac of membrane enclosing a narrow intra-thylakoid space (Lackie and Dow, Dictionary of Cell Biology, 2nd ed). Individual thylakoids are interconnected and tend to stack to form aggregates called grana. They are found in cyanobacteria and all plants.
The two dissimilar sized ribonucleoprotein complexes that comprise a RIBOSOME - the large ribosomal subunit and the small ribosomal subunit. The eukaryotic 80S ribosome is composed of a 60S large subunit and a 40S small subunit. The bacterial 70S ribosome is composed of a 50S large subunit and a 30S small subunit.
The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Vesicles that are involved in shuttling cargo from the interior of the cell to the cell surface, from the cell surface to the interior, across the cell or around the cell to various locations.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in fungi.
The process of moving specific RNA molecules from one cellular compartment or region to another by various sorting and transport mechanisms.
The small subunit of eubacterial RIBOSOMES. It is composed of the 16S RIBOSOMAL RNA and about 23 different RIBOSOMAL PROTEINS.
Proteins involved in the transport of specific substances across the membranes of the MITOCHONDRIA.
The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.
The segregation and degradation of damaged or unwanted cytoplasmic constituents by autophagic vacuoles (cytolysosomes) composed of LYSOSOMES containing cellular components in the process of digestion; it plays an important role in BIOLOGICAL METAMORPHOSIS of amphibians, in the removal of bone by osteoclasts, and in the degradation of normal cell components in nutritional deficiency states.
Electron transfer through the cytochrome system liberating free energy which is transformed into high-energy phosphate bonds.
A family of proteins that promote unwinding of RNA during splicing and translation.
The small ribonucleoprotein component of RIBOSOMES. It contains the MESSENGER RNA binding site and two TRANSFER RNA binding sites - one for the incoming AMINO ACYL TRNA (A site) and the other (P site) for the peptidyl tRNA carrying the elongating peptide chain.
An adaptor protein complex found primarily on perinuclear compartments.
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
A family of MEMBRANE TRANSPORT PROTEINS that require ATP hydrolysis for the transport of substrates across membranes. The protein family derives its name from the ATP-binding domain found on the protein.
Filamentous or elongated proteinaceous structures which extend from the cell surface in gram-negative bacteria that contain certain types of conjugative plasmid. These pili are the organs associated with genetic transfer and have essential roles in conjugation. Normally, only one or a few pili occur on a given donor cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed, p675) This preferred use of "pili" refers to the sexual appendage, to be distinguished from bacterial fimbriae (FIMBRIAE, BACTERIAL), also known as common pili, which are usually concerned with adhesion.
Membrane-limited structures derived from the plasma membrane or various intracellular membranes which function in storage, transport or metabolism.
Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.
A large family of MONOMERIC GTP-BINDING PROTEINS that play a key role in cellular secretory and endocytic pathways. EC 3.6.1.-.
A sirtuin family member found primarily in the CELL NUCLEUS. It is an NAD-dependent deacetylase with specificity towards HISTONES and a variety of proteins involved in gene regulation.
Enzymes that catalyze the cleavage of a carbon-sulfur bond by means other than hydrolysis or oxidation. EC 4.4.
Constituent of the 60S subunit of eukaryotic ribosomes. 5.8S rRNA is involved in the initiation of polypeptide synthesis in eukaryotes.
Diffusible gene products that act on homologous or heterologous molecules of viral or cellular DNA to regulate the expression of proteins.
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
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.
Protein analogs and derivatives of the Aequorea victoria green fluorescent protein that emit light (FLUORESCENCE) when excited with ULTRAVIOLET RAYS. They are used in REPORTER GENES in doing GENETIC TECHNIQUES. Numerous mutants have been made to emit other colors or be sensitive to pH.
Proteins isolated from the outer membrane of Gram-negative bacteria.
A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.
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.
Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.
A complex of proteins that assemble the SNRNP CORE PROTEINS into a core structure that surrounds a highly conserved RNA sequence found in SMALL NUCLEAR RNA. They are found localized in the GEMINI OF COILED BODIES and in the CYTOPLASM. The SMN complex is named after the Survival of Motor Neuron Complex Protein 1, which is a critical component of the complex.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The determination of the pattern of genes expressed at the level of GENETIC TRANSCRIPTION, under specific circumstances or in a specific cell.
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
Self-replicating cytoplasmic organelles of plant and algal cells that contain pigments and may synthesize and accumulate various substances. PLASTID GENOMES are used in phylogenetic studies.
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.
Genes that are located on the MITOCHONDRIAL DNA. Mitochondrial inheritance is often referred to as maternal inheritance but should be differentiated from maternal inheritance that is transmitted chromosomally.
Screening techniques first developed in yeast to identify genes encoding interacting proteins. Variations are used to evaluate interplay between proteins and other molecules. Two-hybrid techniques refer to analysis for protein-protein interactions, one-hybrid for DNA-protein interactions, three-hybrid interactions for RNA-protein interactions or ligand-based interactions. Reverse n-hybrid techniques refer to analysis for mutations or other small molecules that dissociate known interactions.
Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.
The functional hereditary units of FUNGI.
Yeast-like ascomycetous fungi of the family Saccharomycetaceae, order SACCHAROMYCETALES isolated from exuded tree sap.
A whiplike motility appendage present on the surface cells. Prokaryote flagella are composed of a protein called FLAGELLIN. Bacteria can have a single flagellum, a tuft at one pole, or multiple flagella covering the entire surface. In eukaryotes, flagella are threadlike protoplasmic extensions used to propel flagellates and sperm. Flagella have the same basic structure as CILIA but are longer in proportion to the cell bearing them and present in much smaller numbers. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.
The aggregation of soluble ANTIGENS with ANTIBODIES, alone or with antibody binding factors such as ANTI-ANTIBODIES or STAPHYLOCOCCAL PROTEIN A, into complexes large enough to fall out of solution.
Gated transport mechanisms by which proteins or RNA are moved across the NUCLEAR MEMBRANE.
Intracellular fluid from the cytoplasm after removal of ORGANELLES and other insoluble cytoplasmic components.
A cell line generated from human embryonic kidney cells that were transformed with human adenovirus type 5.
Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.
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.
Proton-translocating ATPases responsible for ADENOSINE TRIPHOSPHATE synthesis in the MITOCHONDRIA. They derive energy from the respiratory chain-driven reactions that develop high concentrations of protons within the intermembranous space of the mitochondria.
Physiological processes in biosynthesis (anabolism) and degradation (catabolism) of LIPIDS.
Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.
The assembly of the QUATERNARY PROTEIN STRUCTURE of multimeric proteins (MULTIPROTEIN COMPLEXES) from their composite PROTEIN SUBUNITS.
The chemical reactions involved in the production and utilization of various forms of energy in cells.
Interruption or suppression of the expression of a gene at transcriptional or translational levels.
A subclass of enzymes of the transferase class that catalyze the transfer of a methyl group from one compound to another. (Dorland, 28th ed) EC 2.1.1.
Complexes of RNA-binding proteins with ribonucleic acids (RNA).
A partitioning within cells due to the selectively permeable membranes which enclose each of the separate parts, e.g., mitochondria, lysosomes, etc.
A network of membrane compartments, located at the cytoplasmic side of the GOLGI APPARATUS, where proteins and lipids are sorted for transport to various locations in the cell or cell membrane.
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.
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.
The space between the inner and outer membranes of a cell that is shared with the cell wall.
Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.
Proteins produced from GENES that have acquired MUTATIONS.
Mutagenesis where the mutation is caused by the introduction of foreign DNA sequences into a gene or extragenic sequence. This may occur spontaneously in vivo or be experimentally induced in vivo or in vitro. Proviral DNA insertions into or adjacent to a cellular proto-oncogene can interrupt GENETIC TRANSLATION of the coding sequences or interfere with recognition of regulatory elements and cause unregulated expression of the proto-oncogene resulting in tumor formation.
Porphyrin derivatives containing magnesium that act to convert light energy in photosynthetic organisms.
Self-replicating, short, fibrous, rod-shaped organelles. Each centriole is a short cylinder containing nine pairs of peripheral microtubules, arranged so as to form the wall of the cylinder.
The functional hereditary units of BACTERIA.
A variation of the PCR technique in which cDNA is made from RNA via reverse transcription. The resultant cDNA is then amplified using standard PCR protocols.
Enzymes that hydrolyze GTP to GDP. EC 3.6.1.-.
A multicomponent, ribonucleoprotein complex comprised of one of the family of ARGONAUTE PROTEINS and the "guide strand" of the one of the 20- to 30-nucleotide small RNAs. RISC cleaves specific RNAs, which are targeted for degradation by homology to these small RNAs. Functions in regulating gene expression are determined by the specific argonaute protein and small RNA including siRNA (RNA, SMALL INTERFERING), miRNA (MICRORNA), or piRNA (PIWI-INTERACTING RNA).
Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
The mitochondria of the myocardium.
Components of a cell produced by various separation techniques which, though they disrupt the delicate anatomy of a cell, preserve the structure and physiology of its functioning constituents for biochemical and ultrastructural analysis. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p163)
A family of proteins involved in NUCLEOCYTOPLASMIC TRANSPORT. Karyopherins are heteromeric molecules composed two major types of components, ALPHA KARYOPHERINS and BETA KARYOPHERINS, that function together to transport molecules through the NUCLEAR PORE COMPLEX. Several other proteins such as RAN GTP BINDING PROTEIN and CELLULAR APOPTOSIS SUSCEPTIBILITY PROTEIN bind to karyopherins and participate in the transport process.
Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
Techniques to alter a gene sequence that result in an inactivated gene, or one in which the expression can be inactivated at a chosen time during development to study the loss of function of a gene.
A type of chromogranin which was first isolated from CHROMAFFIN CELLS of the ADRENAL MEDULLA but is also found in other tissues and in many species including human, bovine, rat, mouse, and others. It is an acidic protein with 431 to 445 amino acid residues. It contains fragments that inhibit vasoconstriction or release of hormones and neurotransmitter, while other fragments exert antimicrobial actions.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A complex of enzymes and PROTON PUMPS located on the inner membrane of the MITOCHONDRIA and in bacterial membranes. The protein complex provides energy in the form of an electrochemical gradient, which may be used by either MITOCHONDRIAL PROTON-TRANSLOCATING ATPASES or BACTERIAL PROTON-TRANSLOCATING ATPASES.
A multiribosomal structure representing a linear array of RIBOSOMES held together by messenger RNA; (RNA, MESSENGER); They represent the active complexes in cellular protein synthesis and are able to incorporate amino acids into polypeptides both in vivo and in vitro. (From Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Cells of the higher organisms, containing a true nucleus bounded by a nuclear membrane.
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).
Diseases caused by abnormal function of the MITOCHONDRIA. They may be caused by mutations, acquired or inherited, in mitochondrial DNA or in nuclear genes that code for mitochondrial components. They may also be the result of acquired mitochondria dysfunction due to adverse effects of drugs, infections, or other environmental causes.
The outermost layer of a cell in most PLANTS; BACTERIA; FUNGI; and ALGAE. The cell wall is usually a rigid structure that lies external to the CELL MEMBRANE, and provides a protective barrier against physical or chemical agents.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
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)
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.
The artificial induction of GENE SILENCING by the use of RNA INTERFERENCE to reduce the expression of a specific gene. It includes the use of DOUBLE-STRANDED RNA, such as SMALL INTERFERING RNA and RNA containing HAIRPIN LOOP SEQUENCE, and ANTI-SENSE OLIGONUCLEOTIDES.
The synthesis by organisms of organic chemical compounds, especially carbohydrates, from carbon dioxide using energy obtained from light rather than from the oxidation of chemical compounds. Photosynthesis comprises two separate processes: the light reactions and the dark reactions. In higher plants; GREEN ALGAE; and CYANOBACTERIA; NADPH and ATP formed by the light reactions drive the dark reactions which result in the fixation of carbon dioxide. (from Oxford Dictionary of Biochemistry and Molecular Biology, 2001)
Peptide initiation factors from eukaryotic organisms. Over twelve factors are involved in PEPTIDE CHAIN INITIATION, TRANSLATIONAL in eukaryotic cells. Many of these factors play a role in controlling the rate of MRNA TRANSLATION.
A family of enzymes that catalyze the endonucleolytic cleavage of RNA. It includes EC 3.1.26.-, EC 3.1.27.-, EC 3.1.30.-, and EC 3.1.31.-.
TRANSPORT VESICLES formed when cell-membrane coated pits (COATED PITS, CELL-MEMBRANE) invaginate and pinch off. The outer surface of these vesicles is covered with a lattice-like network of COP (coat protein complex) proteins, either COPI or COPII. COPI coated vesicles transport backwards from the cisternae of the GOLGI APPARATUS to the rough endoplasmic reticulum (ENDOPLASMIC RETICULUM, ROUGH), while COPII coated vesicles transport forward from the rough endoplasmic reticulum to the Golgi apparatus.
Short chains of RNA (100-300 nucleotides long) that are abundant in the nucleus and usually complexed with proteins in snRNPs (RIBONUCLEOPROTEINS, SMALL NUCLEAR). Many function in the processing of messenger RNA precursors. Others, the snoRNAs (RNA, SMALL NUCLEOLAR), are involved with the processing of ribosomal RNA precursors.
Proteins found in any species of protozoan.
The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.
Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
An enzyme that catalyzes the formation of acetoacetyl-CoA from two molecules of ACETYL COA. Some enzymes called thiolase or thiolase-I have referred to this activity or to the activity of ACETYL-COA C-ACYLTRANSFERASE.

UV irradiation of polycyclic aromatic hydrocarbons in ices: production of alcohols, quinones, and ethers. (1/385)

Polycyclic aromatic hydrocarbons (PAHs) in water ice were exposed to ultraviolet (UV) radiation under astrophysical conditions, and the products were analyzed by infrared spectroscopy and mass spectrometry. Peripheral carbon atoms were oxidized, producing aromatic alcohols, ketones, and ethers, and reduced, producing partially hydrogenated aromatic hydrocarbons, molecules that account for the interstellar 3.4-micrometer emission feature. These classes of compounds are all present in carbonaceous meteorites. Hydrogen and deuterium atoms exchange readily between the PAHs and the ice, which may explain the deuterium enrichments found in certain meteoritic molecules. This work has important implications for extraterrestrial organics in biogenesis.  (+info)

Divergence time estimates for the early history of animal phyla and the origin of plants, animals and fungi. (2/385)

In the past, molecular clocks have been used to estimate divergence times among animal phyla, but those time estimates have varied widely (1200-670 million years ago, Ma). In order to obtain time estimates that are more robust, we have analysed a larger number of genes for divergences among three well-represented animal phyla, and among plants, animals and fungi. The time estimate for the chordate-arthropod divergence, using 50 genes, is 993 +/- 46 Ma. Nematodes were found to have diverged from the lineage leading to arthropods and chordates at 1177 +/- 79 Ma. Phylogenetic analyses also show that a basal position of nematodes has strong support (p > 99%) and is not the result of rate biases. The three-way split (relationships unresolved) of plants, animals and fungi was estimated at 1576 +/- 88 Ma. By inference, the basal animal phyla (Porifera, Cnidaria, Ctenophora) diverged between about 1200-1500 Ma. This suggests that at least six animal phyla originated deep in the Precambrian, more than 400 million years earlier than their first appearance in the fossil record.  (+info)

Prebiotic cytosine synthesis: a critical analysis and implications for the origin of life. (3/385)

A number of theories propose that RNA, or an RNA-like substance, played a role in the origin of life. Usually, such hypotheses presume that the Watson-Crick bases were readily available on prebiotic Earth, for spontaneous incorporation into a replicator. Cytosine, however, has not been reported in analyses of meteorites nor is it among the products of electric spark discharge experiments. The reported prebiotic syntheses of cytosine involve the reaction of cyanoacetylene (or its hydrolysis product, cyanoacetaldehyde), with cyanate, cyanogen, or urea. These substances undergo side reactions with common nucleophiles that appear to proceed more rapidly than cytosine formation. To favor cytosine formation, reactant concentrations are required that are implausible in a natural setting. Furthermore, cytosine is consumed by deamination (the half-life for deamination at 25 degrees C is approximately 340 yr) and other reactions. No reactions have been described thus far that would produce cytosine, even in a specialized local setting, at a rate sufficient to compensate for its decomposition. On the basis of this evidence, it appears quite unlikely that cytosine played a role in the origin of life. Theories that involve replicators that function without the Watson-Crick pairs, or no replicator at all, remain as viable alternatives.  (+info)

Molecular evolution: aminoacyl-tRNA synthetases on the loose. (4/385)

Modified versions - paralogs - of the catalytic domain of at least three different aminoacyl-tRNA synthetases have been found to serve catalytic or regulatory roles in other reactions. These findings suggest that the first modern tRNA-synthetases could have been derived from amino-acid biosynthetic enzymes.  (+info)

Ribozymes--why so many, why so few? (5/385)

The RNA world scenario posits the existence of catalytic and genetic networks whose reactions are catalyzed by RNAs. Substantial progress has been made in recent years in the selection of RNA catalysts by SELEX, thus verifying one prediction of the model. However, many selected catalysts are long molecules, leading to a question of whether they could have been synthesized by a primitive replicator. It is proposed that the efficiency of some small ribozymes may have been augmented by other RNAs acting as transactivators.  (+info)

The evolution of a universal genetic code. (6/385)

Some of the basic problems presented by the rapid evolution of a universal genetic code can be resolved by a mechanism of co-evolution of the code and the amino acids it serves.  (+info)

Life: past, present and future. (7/385)

Molecular methods of taxonomy and phylogeny have changed the way in which life on earth is viewed; they have allowed us to transition from a eukaryote-centric (five-kingdoms) view of the planet to one that is peculiarly prokarote-centric, containing three kingdoms, two of which are prokaryotic unicells. These prokaryotes are distinguished from their eukaryotic counterparts by their toughness, tenacity and metabolic diversity. Realization of these features has, in many ways, changed the way we feel about life on earth, about the nature of life past and about the possibility of finding life elsewhere. In essence, the limits of life on this planet have expanded to such a degree that our thoughts of both past and future life have been altered. The abilities of prokaryotes to withstand many extreme conditions has led to the term extremophiles, used to describe the organisms that thrive under conditions thought just a few years ago, to be inconsistent with life. Perhaps the most extensive adaptation to extreme conditions, however, is represented by the ability of many bacteria to survive nutrient conditions not compatible with eukaryotic life. Prokaryotes have evolved to use nearly every redox couple that is in abundance on earth, filling the metabolic niches left behind by the oxygen-using, carbon-eating eukaryotes. This metabolic plasticity leads to a common feature in physically stratified environments of layered microbial communities, chemical indicators of the metabolic diversity of the prokaryotes. Such 'metabolic extremophily' forms a backdrop by which we can view the energy flow of life on this planet, think about what the evolutionary past of the planet might have been, and plan ways to look for life elsewhere, using the knowledge of energy flow on earth.  (+info)

The missing organic molecules on Mars. (8/385)

GC-MS on the Viking 1976 Mars missions did not detect organic molecules on the Martian surface, even those expected from meteorite bombardment. This result suggested that the Martian regolith might hold a potent oxidant that converts all organic molecules to carbon dioxide rapidly relative to the rate at which they arrive. This conclusion is influencing the design of Mars missions. We reexamine this conclusion in light of what is known about the oxidation of organic compounds generally and the nature of organics likely to come to Mars via meteorite. We conclude that nonvolatile salts of benzenecarboxylic acids, and perhaps oxalic and acetic acid, should be metastable intermediates of meteoritic organics under oxidizing conditions. Salts of these organic acids would have been largely invisible to GC-MS. Experiments show that one of these, benzenehexacarboxylic acid (mellitic acid), is generated by oxidation of organic matter known to come to Mars, is rather stable to further oxidation, and would not have been easily detected by the Viking experiments. Approximately 2 kg of meteorite-derived mellitic acid may have been generated per m(2) of Martian surface over 3 billion years. How much remains depends on decomposition rates under Martian conditions. As available data do not require that the surface of Mars be very strongly oxidizing, some organic molecules might be found near the surface of Mars, perhaps in amounts sufficient to be a resource. Missions should seek these and recognize that these complicate the search for organics from entirely hypothetical Martian life.  (+info)

Peroxisomal disorders can be caused by mutations in genes that encode peroxisomal enzymes or other proteins involved in peroxisome function. These mutations can lead to a range of symptoms, including developmental delay, intellectual disability, seizures, and a variety of physical abnormalities.

There are several types of peroxisomal disorders, including:

1. Zellweger syndrome: This is the most common type of peroxisomal disorder, and it is caused by mutations in the PEX1 gene. It is characterized by severe developmental delay, intellectual disability, seizures, and physical abnormalities such as a small head, short stature, and vision loss.
2. Neonatal adrenoleukodystrophy (NALD): This is a rare and fatal disorder caused by mutations in the ABCD1 gene. It is characterized by progressive loss of myelin, a fatty insulating layer that surrounds nerve fibers, leading to severe brain damage and death in early childhood.
3. Peroxisomal biogenesis disorder (PBD): This is a group of rare disorders caused by mutations in several different genes involved in peroxisome biogenesis. Symptoms can vary widely, but may include developmental delay, intellectual disability, seizures, and physical abnormalities.
4. X-linked adrenoleukodystrophy (X-ALD): This is a rare disorder caused by mutations in the ABCD1 gene, which is located on the X chromosome. It is characterized by progressive loss of myelin leading to severe brain damage and death in early childhood.

Peroxisomal disorders are usually diagnosed through a combination of clinical evaluation, laboratory tests, and genetic analysis. Treatment for these disorders is limited and often focuses on managing symptoms and preventing complications. Some potential treatments include:

1. Bone marrow transplantation: This may be effective in certain cases of adrenoleukodystrophy and other peroxisomal disorders, although the procedure carries significant risks and is not always available or appropriate for all patients.
2. Enzyme replacement therapy (ERT): This involves replacing the missing enzyme with a synthetic version, which can help to reduce symptoms and slow disease progression in some cases.
3. Dietary changes: In some cases, dietary modifications may be helpful in managing symptoms and preventing complications of peroxisomal disorders. For example, patients with X-linked adrenoleukodystrophy may benefit from a diet low in saturated fats and very long-chain fatty acids.
4. Physical therapy and occupational therapy: These interventions can help to improve mobility, balance, and cognitive function in patients with peroxisomal disorders.
5. Supportive care: This may include medications to manage seizures, pain, and other symptoms, as well as support for respiratory and other bodily functions in more severe cases of the disorders.
6. Stem cell therapy: This is a promising area of research that may offer new treatment options for peroxisomal disorders in the future.
7. Gene therapy: This approach involves using genes to treat or prevent diseases, and it is being explored as a potential treatment for some peroxisomal disorders.
8. Prenatal testing: In some cases, prenatal testing may be available to identify genetic mutations that cause peroxisomal disorders before birth.
9. Counseling and support: It is important for patients with peroxisomal disorders and their families to receive emotional support and counseling to help them cope with the challenges of these conditions.

Overall, the treatment of peroxisomal disorders is complex and may involve a combination of different interventions, depending on the specific diagnosis and needs of each patient. In many cases, early detection and intervention can help to improve outcomes and reduce the risk of complications.

The main symptoms of Hermanski-Pudlak syndrome include:

1. Vision loss: People with this condition often experience progressive vision loss, starting in childhood or adolescence, which can lead to blindness in early adulthood.
2. Skin abnormalities: The skin of people with Hermanski-Pudlak syndrome is typically pale and has a characteristic "marbled" appearance due to the presence of white patches.
3. Neurological problems: Some individuals with this condition may experience neurological symptoms such as seizures, learning disabilities, and difficulty with balance and coordination.
4. Hearing loss: Hearing loss is a common feature of Hermanski-Pudlak syndrome, and can range from mild to profound.
5. Other signs: People with this condition may also experience other symptoms such as hair loss, thinning or brittle nails, and an increased risk of infections.

Hermanski-Pudlak syndrome is a rare disorder, and the exact prevalence is not known. However, it is estimated to affect approximately 1 in 1 million people worldwide. The condition is inherited in an autosomal recessive pattern, which means that a person must inherit two copies of the mutated HPS gene (one from each parent) to develop the syndrome.

There is currently no cure for Hermanski-Pudlak syndrome, and treatment is focused on managing the symptoms. This can include medications to control seizures, physical therapy to improve balance and coordination, and assistive devices such as glasses or hearing aids to help with vision and hearing loss.

Overall, Hermanski-Pudlak syndrome is a rare and complex disorder that affects multiple systems in the body. While there is currently no cure, early diagnosis and ongoing management can help improve the quality of life for individuals affected by this condition.

The disorder is caused by mutations in the PEX1, PEX2, or PEX3 genes, which are involved in the peroxisomal biogenesis pathway. The defective peroxisomes are unable to function properly, leading to a wide range of symptoms and complications.

Zellweger syndrome typically affects infants and children, and the symptoms may include:

1. Developmental delays and intellectual disability
2. Hypotonia (low muscle tone)
3. Ataxia (poor coordination)
4. Cerebellar atrophy (shrinkage of the cerebellum)
5. Seizures
6. Hydrocephalus (fluid accumulation in the brain)
7. Hepatic dysfunction (liver problems)
8. Nephropathy (kidney damage)
9. Retinal degeneration (vision loss)
10. Skeletal abnormalities, such as short stature and joint deformities.

There is no cure for Zellweger syndrome, and treatment is focused on managing the symptoms and preventing complications. In some cases, liver transplantation may be necessary. The prognosis for the disorder is generally poor, and many individuals with Zellweger syndrome do not survive beyond early childhood.

Zellweger syndrome is a rare disorder, and its prevalence is unknown. However, it is estimated to affect approximately 1 in 50,000 newborns worldwide. The disorder is often diagnosed during infancy or early childhood, based on a combination of clinical features and laboratory tests, such as genetic analysis.

Overall, Zellweger syndrome is a severe and debilitating disorder that affects multiple systems in the body. While there is no cure for the disorder, early diagnosis and appropriate management can help improve the quality of life for affected individuals.

Mitochondrial diseases can affect anyone, regardless of age or gender, and they can be caused by mutations in either the mitochondrial DNA (mtDNA) or the nuclear DNA (nDNA). These mutations can be inherited from one's parents or acquired during embryonic development.

Some of the most common symptoms of mitochondrial diseases include:

1. Muscle weakness and wasting
2. Seizures
3. Cognitive impairment
4. Vision loss
5. Hearing loss
6. Heart problems
7. Neurological disorders
8. Gastrointestinal issues
9. Liver and kidney dysfunction

Some examples of mitochondrial diseases include:

1. MELAS syndrome (Mitochondrial Myopathy, Encephalopathy, Lactic Acidosis, and Stroke-like episodes)
2. Kearns-Sayre syndrome (a rare progressive disorder that affects the nervous system and other organs)
3. Chronic progressive external ophthalmoplegia (CPEO), which is characterized by weakness of the extraocular muscles and vision loss
4. Mitochondrial DNA depletion syndrome, which can cause a wide range of symptoms including seizures, developmental delays, and muscle weakness.
5. Mitochondrial myopathy, encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS)
6. Leigh syndrome, which is a rare genetic disorder that affects the brain and spinal cord.
7. LHON (Leber's Hereditary Optic Neuropathy), which is a rare form of vision loss that can lead to blindness in one or both eyes.
8. Mitochondrial DNA mutation, which can cause a wide range of symptoms including seizures, developmental delays, and muscle weakness.
9. Mitochondrial myopathy, encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS)
10. Kearns-Sayre syndrome, which is a rare progressive disorder that affects the nervous system and other organs.

It's important to note that this is not an exhaustive list and there are many more mitochondrial diseases and disorders that can affect individuals. Additionally, while these diseases are rare, they can have a significant impact on the quality of life of those affected and their families.

Source: Genetic Home Reference: NIH

There are several types of ocular albinism, including:

1. Oculocutaneous albinism (OCA) - This is the most common form of ocular albinism and affects both the eyes and skin. It is caused by mutations in the TYR gene, which codes for the enzyme tyrosinase, which is involved in the production of melanin.
2. Hermansky-Pudlak syndrome (HPS) - This is a rare form of ocular albinism that affects both the eyes and platelets. It is caused by mutations in the HPS gene, which codes for the protein hermansky-pudlak syndrome, which is involved in the production of melanin.
3. Juvenile macular degeneration (JMD) - This is a rare form of ocular albinism that affects only the eyes and is caused by mutations in the RPE65 gene, which codes for the protein RPE65, which is involved in the production of melanin.

The symptoms of ocular albinism can vary depending on the type and severity of the condition, but they may include:

* Poor visual acuity (blurred vision)
* Sensitivity to light (photophobia)
* Difficulty seeing colors and fine details
* Eye movements that are slow or uncoordinated
* Increased risk of eye problems such as cataracts, glaucoma, and retinal detachment
* Skin that is pale or freckled

There is no cure for ocular albinism, but treatment options may include glasses or contact lenses to improve vision, medication to reduce the risk of eye problems, and surgery to correct eye alignment or remove cataracts. Early diagnosis and treatment can help manage the symptoms and prevent complications.

There are several types of mitochondrial myopathies, each with different clinical features and inheritance patterns. Some of the most common forms include:

1. Kearns-Sayre syndrome: This is a rare progressive disorder that affects the nervous system, muscles, and other organs. It is characterized by weakness and paralysis, seizures, and vision loss.
2. MELAS syndrome (mitochondrial myopathy, encephalomyopathy, lactic acidosis, and stroke-like episodes): This condition is characterized by recurring stroke-like episodes, seizures, muscle weakness, and cognitive decline.
3. MERRF (myoclonic epilepsy with ragged red fibers): This disorder is characterized by myoclonus (muscle jerks), seizures, and progressive muscle weakness.
4. LHON (Leber's hereditary optic neuropathy): This condition affects the optic nerve and can lead to sudden vision loss.

The symptoms of mitochondrial myopathies can vary widely, depending on the specific disorder and the severity of the mutation. They may include muscle weakness, muscle cramps, muscle wasting, seizures, vision loss, and cognitive decline.

There is no cure for mitochondrial myopathies, but various treatments can help manage the symptoms. These may include physical therapy, medications to control seizures or muscle spasms, and nutritional supplements to support energy production. In some cases, a lung or heart-lung transplant may be necessary.

The diagnosis of a mitochondrial myopathy is based on a combination of clinical findings, laboratory tests, and genetic analysis. Laboratory tests may include blood tests to measure the levels of certain enzymes and other molecules in the body, as well as muscle biopsy to examine the muscle tissue under a microscope. Genetic testing can help identify the specific mutation responsible for the condition.

The prognosis for mitochondrial myopathies varies depending on the specific disorder and the severity of the symptoms. Some forms of the disease are slowly progressive, while others may be more rapidly debilitating. In general, the earlier the diagnosis and treatment, the better the outcome.

There is currently no cure for mitochondrial myopathies, but research is ongoing to develop new treatments and therapies. In addition, there are several organizations and support groups that provide information and resources for individuals with these conditions and their families.

The term "mucolipidoses" was coined by the American pediatrician and medical geneticist Dr. Victor A. McKusick in the 1960s to describe this group of diseases. The term is derived from the Greek words "muco-," meaning mucus, and "-lipido-," meaning fat, and "-osis," meaning condition or disease.

There are several types of mucolipidoses, including:

1. Mucolipidosis type I (MLI): This is the most common form of the disorder and is caused by a deficiency of the enzyme galactocerebrosidase (GALC).
2. Mucolipidosis type II (MLII): This form of the disorder is caused by a deficiency of the enzyme sulfatases, which are necessary for the breakdown of sulfated glycosaminoglycans (sGAGs).
3. Mucolipidosis type III (MLIII): This form of the disorder is caused by a deficiency of the enzyme acetyl-CoA:beta-glucoside ceramide beta-glucosidase (CERBGL), which is necessary for the breakdown of glycosphingolipids.
4. Mucolipidosis type IV (MLIV): This form of the disorder is caused by a deficiency of the enzyme glucocerebrosidase (GUCB), which is necessary for the breakdown of glucocerebroside, a type of glycosphingolipid.

Mucolipidoses are usually diagnosed by measuring the activity of the enzymes involved in glycosphingolipid metabolism in white blood cells or fibroblasts, and by molecular genetic analysis to identify mutations in the genes that code for these enzymes. Treatment is typically focused on managing the symptoms and may include physical therapy, speech therapy, and other supportive care measures. Bone marrow transplantation has been tried in some cases as a potential treatment for mucolipidosis, but the outcome has been variable.

Prognosis: The prognosis for mucolipidoses is generally poor, with most individuals with the disorder dying before the age of 10 years due to severe neurological and other complications. However, with appropriate management and supportive care, some individuals with milder forms of the disorder may survive into adulthood.

Epidemiology: Mucolipidoses are rare disorders, with an estimated prevalence of 1 in 100,000 to 1 in 200,000 births. They affect both males and females equally, and there is no known geographic or ethnic predilection.

Clinical features: The clinical features of mucolipidoses vary depending on the specific type of disorder and the severity of the mutation. Common features include:

* Delayed development and intellectual disability
* Seizures
* Vision loss or blindness
* Hearing loss or deafness
* Poor muscle tone and coordination
* Increased risk of infections
* Coarsening of facial features
* Enlarged liver and spleen
* Abnormalities of the heart, including ventricular septal defect and atrial septal defect

Diagnosis: Diagnosis of mucolipidoses is based on a combination of clinical features, laboratory tests, and genetic analysis. Laboratory tests may include measurement of enzyme activity in white blood cells, urine testing, and molecular genetic analysis.

Treatment and management: There is no cure for mucolipidoses, but treatment and management strategies can help manage the symptoms and improve quality of life. These may include:

* Physical therapy to improve muscle tone and coordination
* Speech therapy to improve communication skills
* Occupational therapy to improve daily living skills
* Anticonvulsant medications to control seizures
* Supportive care to manage infections and other complications
* Genetic counseling to discuss the risk of inheritance and options for family planning.

Prognosis: The prognosis for mucolipidoses varies depending on the specific type and severity of the condition. In general, the prognosis is poor for children with more severe forms of the disorder, while those with milder forms may have a better outlook. With appropriate management and supportive care, some individuals with mucolipidoses can lead relatively normal lives, while others may require ongoing medical care and assistance throughout their lives.

There are different types of SMA, ranging from mild to severe, with varying degrees of muscle wasting and weakness. The condition typically becomes apparent during infancy or childhood and can progress rapidly or slowly over time. Symptoms may include muscle weakness, spinal curvature (scoliosis), respiratory problems, and difficulty swallowing.

SMA is caused by a defect in the Survival Motor Neuron 1 (SMN1) gene, which is responsible for producing a protein that protects motor neurons from degeneration. The disorder is usually inherited in an autosomal recessive pattern, meaning that a person must inherit two copies of the defective gene - one from each parent - to develop the condition.

There is currently no cure for SMA, but various treatments are available to manage its symptoms and slow its progression. These may include physical therapy, occupational therapy, bracing, and medications to improve muscle strength and function. In some cases, stem cell therapy or gene therapy may be considered as potential treatment options.

Prognosis for SMA varies depending on the type and severity of the condition, but it is generally poor for those with the most severe forms of the disorder. However, with appropriate management and support, many individuals with SMA can lead fulfilling lives and achieve their goals despite physical limitations.

The symptoms of sideroblastic anemia can vary depending on the severity of the condition, but may include fatigue, weakness, pale skin, shortness of breath, and a rapid heart rate. Treatment options for sideroblastic anemia typically involve addressing the underlying genetic cause of the condition, such as through gene therapy or enzyme replacement therapy, and managing symptoms with medication and lifestyle modifications.

In summary, sideroblastic anemia is a rare inherited disorder characterized by abnormalities in iron metabolism that can lead to impaired red blood cell production and various other symptoms. It is important for individuals with this condition to receive timely and appropriate medical attention to manage their symptoms and prevent complications.

While lipomatosis is not a life-threatening condition, it can cause discomfort and pain due to the size and location of the lipomas. In some cases, lipomatosis may also lead to other health problems, such as obesity, joint pain, and sleep apnea.

There are several risk factors for developing lipomatosis, including:

* Genetics: Lipomatosis can be inherited from one's parents.
* Obesity: Excess weight is a major risk factor for developing lipomatosis.
* Hormonal changes: Changes in hormone levels, such as those that occur during pregnancy or menopause, can increase the risk of developing lipomatosis.
* Age: Lipomatosis is more common in adults over the age of 40.
* Gender: Women are more likely to develop lipomatosis than men.

There are several treatment options for lipomatosis, including:

* Liposuction: A surgical procedure that removes excess fat cells.
* Medications: Certain medications, such as corticosteroids and antidepressants, can help reduce the size of lipomas.
* Diet and exercise: Maintaining a healthy diet and exercise routine can help reduce body weight and alleviate symptoms of lipomatosis.

It is important to note that while lipomatosis is not a life-threatening condition, it can have a significant impact on a person's quality of life. If you suspect you may be experiencing symptoms of lipomatosis, it is important to consult with a healthcare professional for proper diagnosis and treatment.

Symptoms of Refsum disease typically begin in early adulthood and may include:

* Muscle weakness and wasting
* Loss of coordination and balance
* Vision problems
* Hearing loss
* Cognitive decline and dementia
* Memory loss
* Seizures
* Speech difficulties

Refsum disease is caused by mutations in the PAH gene, which codes for the enzyme phytanic acid hydrolase. This enzyme plays a crucial role in breaking down phytanic acid, a fatty substance found in certain foods. Without this enzyme, phytanic acid accumulates in the body and is thought to contribute to the degeneration of nerve cells in the brain and other parts of the nervous system.

There is no cure for Refsum disease, but treatment may include:

* Dietary restrictions to limit intake of phytanic acid
* Vitamin supplements to support the body's natural detoxification processes
* Physical therapy to maintain muscle strength and mobility
* Speech and language therapy to improve communication skills
* Medications to manage seizures and other symptoms

Prognosis for Refsum disease is generally poor, with most individuals experiencing significant neurological decline over time. However, the rate of progression can vary widely, and some individuals may experience a more gradual decline over many years. With appropriate treatment and supportive care, some individuals with Refsum disease may be able to maintain their quality of life for several years or even decades.

The symptoms of ALD usually become apparent in childhood or adolescence and can vary in severity. They may include:

* Adrenal insufficiency (a decrease in the production of hormones by the adrenal glands)
* Seizures
* Vision loss
* Cognitive decline
* Behavioral changes
* Muscle weakness and wasting

ALD is an X-linked disorder, meaning that it is more common in males than in females. Females can be carriers of the mutated gene, but they typically do not develop symptoms themselves.

There is no cure for ALD, but treatment options are available to manage the symptoms and slow the progression of the disease. These may include:

* Steroids to replace adrenal hormones
* Anticonvulsants to control seizures
* Physical therapy to maintain muscle strength and mobility
* Dietary changes to reduce fat intake and improve nutrition

Bone marrow transplantation has also been explored as a potential treatment for ALD, but the results are still uncertain.

The diagnosis of ALD is based on a combination of clinical findings, laboratory tests, and genetic analysis. Laboratory tests may include:

* Measurement of very long-chain fatty acids in the blood and cerebrospinal fluid
* Genetic testing to identify the mutation in the ABCD1 gene

The prognosis for ALD is generally poor, and the disease can be fatal within a few years of onset. However, with appropriate treatment and management, some individuals with ALD may experience a slowing of the disease progression and an improvement in their quality of life.

1. Abnormal formation of the mandible, which can be shortened, misshapen or absent.
2. Facial asymmetry, with one side of the face appearing smaller or more underdeveloped than the other.
3. Cleft lip and/or palate.
4. Ear deformities, such as small or missing ear canals.
5. Eye problems, including microphthalmia (small eyes) or anophthalmia (absence of one or both eyes).
6. Distorted or underdeveloped nasal passages and sinuses.
7. Sleep apnea and other respiratory difficulties due to the narrowing of the airway.
8. Difficulty swallowing and feeding, particularly in infants.
9. Speech and hearing impairments.
10. Delayed growth and development, both intellectually and physically.

Mandibulofacial dysostosis is caused by mutations in several genes that are involved in the formation of the mandible and facial bones during fetal development. The condition is usually inherited in an autosomal dominant pattern, meaning that a single copy of the mutated gene is enough to cause the condition. However, some cases may be caused by sporadic mutations or inherited in a more complex pattern.

There is no cure for mandibulofacial dysostosis, but treatment options are available to manage the symptoms and improve quality of life. These may include:

1. Orthodontic and orthopedic treatments to align and stabilize the teeth and jawbones.
2. Surgery to correct facial asymmetry and improve airway function.
3. Speech therapy to address communication difficulties.
4. Hearing aids or cochlear implants for hearing impairments.
5. Regular monitoring and management of associated health problems, such as sleep apnea and respiratory infections.

Early diagnosis and intervention are crucial for the best possible outcomes in individuals with mandibulofacial dysostosis. With appropriate treatment and support, many people with this condition can lead fulfilling lives and achieve their goals.

The symptoms of Leigh disease usually become apparent during infancy or early childhood and may include:

* Delayed development
* Loss of motor skills
* Muscle weakness
* Seizures
* Vision loss
* Hearing loss
* Poor feeding and growth

Leigh disease is often diagnosed through a combination of clinical evaluations, laboratory tests, and imaging studies such as MRI or CT scans. There is no cure for Leigh disease, but treatment may include supportive care, such as physical therapy, occupational therapy, and speech therapy, as well as medications to manage seizures and other symptoms. In some cases, a liver transplant may be necessary.

The progression of Leigh disease can vary widely, and the age of onset and rate of progression can vary depending on the specific type of mutation causing the disorder. Some forms of Leigh disease are more severe and progress rapidly, while others may be milder and progress more slowly. In general, however, the disease tends to progress over time, with worsening symptoms and declining function.

Leigh disease is a rare disorder, and there is no specific data on its prevalence. However, it is estimated that mitochondrial disorders, of which Leigh disease is one type, affect approximately 1 in 4,000 people in the United States.

1) They share similarities with humans: Many animal species share similar biological and physiological characteristics with humans, making them useful for studying human diseases. For example, mice and rats are often used to study diseases such as diabetes, heart disease, and cancer because they have similar metabolic and cardiovascular systems to humans.

2) They can be genetically manipulated: Animal disease models can be genetically engineered to develop specific diseases or to model human genetic disorders. This allows researchers to study the progression of the disease and test potential treatments in a controlled environment.

3) They can be used to test drugs and therapies: Before new drugs or therapies are tested in humans, they are often first tested in animal models of disease. This allows researchers to assess the safety and efficacy of the treatment before moving on to human clinical trials.

4) They can provide insights into disease mechanisms: Studying disease models in animals can provide valuable insights into the underlying mechanisms of a particular disease. This information can then be used to develop new treatments or improve existing ones.

5) Reduces the need for human testing: Using animal disease models reduces the need for human testing, which can be time-consuming, expensive, and ethically challenging. However, it is important to note that animal models are not perfect substitutes for human subjects, and results obtained from animal studies may not always translate to humans.

6) They can be used to study infectious diseases: Animal disease models can be used to study infectious diseases such as HIV, TB, and malaria. These models allow researchers to understand how the disease is transmitted, how it progresses, and how it responds to treatment.

7) They can be used to study complex diseases: Animal disease models can be used to study complex diseases such as cancer, diabetes, and heart disease. These models allow researchers to understand the underlying mechanisms of the disease and test potential treatments.

8) They are cost-effective: Animal disease models are often less expensive than human clinical trials, making them a cost-effective way to conduct research.

9) They can be used to study drug delivery: Animal disease models can be used to study drug delivery and pharmacokinetics, which is important for developing new drugs and drug delivery systems.

10) They can be used to study aging: Animal disease models can be used to study the aging process and age-related diseases such as Alzheimer's and Parkinson's. This allows researchers to understand how aging contributes to disease and develop potential treatments.

Refsum disease typically affects infants in the first few months of life. The initial symptoms may include poor muscle tone, weakness, seizures, and difficulty moving the eyes. As the disease progresses, children may develop intellectual disability, loss of coordination and balance, and vision problems. Eventually, children with Refsum disease may become unable to walk, talk, or care for themselves.

Refsum disease is caused by mutations in the PAH gene, which encodes the enzyme phytanic acid hydroxylase. This condition is inherited in an autosomal recessive pattern, meaning that a child must inherit two copies of the mutated gene, one from each parent, to develop the disease.

There is no cure for Refsum disease, and treatment is focused on managing the symptoms and preventing complications. This may include physical therapy, occupational therapy, and medications to control seizures and muscle spasms. In some cases, a low-fat diet may be recommended to help reduce the accumulation of fatty acids in the body.

Prognosis for children with Refsum disease is generally poor, and many individuals with this condition will not survive beyond childhood. Those who do survive may have significant cognitive and physical disabilities, and may require lifelong care and support.

The term "chondrodysplasia" refers to a group of genetic disorders that affect the development of cartilage and bone. "Punctata" means "spotted" in Latin, referring to the small, dark spots on the skin that are a hallmark of the condition. "Rhizomelic" refers to the shortening of the limbs, particularly the arms and legs.

The exact prevalence of CDPR is not known, but it is estimated to affect approximately 1 in 1 million births worldwide. The disorder is caused by mutations in genes that are important for cartilage and bone development, and it can be inherited in an autosomal dominant or recessive pattern, depending on the specific mutation.

The symptoms of CDPR usually become apparent during early childhood and may include:

* Short stature with shortened limbs
* Joint deformities, such as clubfoot or bowed legs
* Characteristic skin changes, including small, dark spots on the skin
* Delayed development of motor skills
* Intellectual disability in some cases

There is no cure for CDPR, but treatment may include physical therapy, braces or splints to help straighten joints, and surgery to correct deformities. In some cases, medication may be prescribed to manage associated conditions such as pain or inflammation.

The prognosis for individuals with CDPR varies depending on the severity of the disorder and the presence of any additional health issues. Some individuals with mild forms of the condition may lead relatively normal lives, while others may experience significant limitations in their daily activities and quality of life. Early diagnosis and appropriate management are important to help optimize outcomes for individuals with CDPR.

Hypopigmentation can be classified into two main types:

1. Localized hypopigmentation - This type of hypopigmentation occurs in a specific area of the body, such as vitiligo, where there is a loss of melanin-producing cells.
2. Widespread hypopigmentation - This type of hypopigmentation affects multiple areas of the body and can be caused by systemic conditions such as hypothyroidism or Addison's disease.

Some common causes of hypopigmentation include:

1. Vitiligo - An autoimmune condition that causes the loss of melanocytes in specific areas of the skin.
2. Alopecia areata - A condition where hair follicles are damaged or lost, leading to patchy hair loss.
3. Thyroid disorders - Hypothyroidism (underactive thyroid) can cause decreased melanin production, while hyperthyroidism (overactive thyroid) can cause increased melanin production.
4. Addison's disease - A rare endocrine disorder that affects the adrenal glands and can cause hypopigmentation.
5. Autoimmune conditions - Conditions such as lupus or rheumatoid arthritis can cause inflammation that leads to hypopigmentation.
6. Trauma - Injury to the skin can cause hypopigmentation, especially if it involves the loss of melanocytes.
7. Infections - Certain infections such as tuberculosis or syphilis can cause hypopigmentation.
8. Nutritional deficiencies - Deficiencies in vitamins and minerals such as vitamin B12 or iron can affect melanin production.

Symptoms of hypopigmentation may include:

1. Lighter skin tone than usual
2. Patchy or uneven skin tone
3. Increased risk of sunburn and skin damage due to decreased melanin protection
4. Skin that appears thin and translucent
5. Freckles or other pigmentary changes
6. Hair loss or thinning
7. Nail abnormalities such as ridging or thinning
8. Increased sensitivity to the sun
9. Difficulty healing of wounds or injuries
10. Skin that is prone to irritation or inflammation.

Hypopigmentation can be diagnosed through a physical examination, and in some cases, additional tests such as blood work or biopsies may be necessary to rule out underlying conditions. Treatment for hypopigmentation depends on the underlying cause and may include topical creams or ointments, medications, or laser therapy. It is important to consult a dermatologist or other healthcare professional for proper diagnosis and treatment.

Bowen's disease typically appears as a scaly, flat patch or plaque on sun-exposed areas of the skin, such as the face, ears, neck, and arms. The affected skin may be pink or red, and may have a sandpapery texture. In some cases, Bowen's disease can ulcerate and bleed.

Bowen's disease is caused by a combination of genetic predisposition and exposure to ultraviolet (UV) radiation from the sun or tanning beds. It is more common in fair-skinned individuals and those who have a history of prolonged sun exposure.

The diagnosis of Bowen's disease is based on a combination of clinical findings, histopathology, and immunohistochemistry. Treatment options for Bowen's disease include topical therapy with imiquimod cream or 5-fluorouracil (5-FU) cream, photodynamic therapy, and surgical excision.

While Bowen's disease is a precancerous condition, it can occasionally progress to invasive squamous cell carcinoma if left untreated. Therefore, early detection and treatment are important for preventing progression to more advanced and potentially life-threatening skin cancers.

There are several reasons why an embryo may not survive, including:

1. Immunological factors: The mother's immune system may reject the embryo, leading to its death.
2. Hormonal imbalance: An imbalance of hormones can disrupt the development of the embryo and lead to its demise.
3. Chromosomal abnormalities: The embryo may have an abnormal number of chromosomes, which can prevent it from developing properly.
4. Infections: Certain infections, such as group B strep or Listeria, can cause the embryo to fail to develop.
5. Maternal health issues: Chronic medical conditions, such as diabetes or hypertension, can increase the risk of embryo loss.
6. Smoking and drug use: Smoking and drug use have been linked to an increased risk of embryo loss.
7. Age: Women over 35 may be at a higher risk of embryo loss due to age-related factors.
8. Poor egg quality: The quality of the eggs used for fertilization can affect the success of the pregnancy.
9. Embryo fragmentation: The embryos may be damaged during the transfer process, leading to their failure to develop.
10. Uterine abnormalities: Abnormalities in the shape or structure of the uterus can increase the risk of embryo loss.

Embryo loss can be a traumatic experience for couples trying to conceive. It is essential to seek medical advice if there are multiple instances of embryo loss, as it may indicate an underlying issue that needs to be addressed.

Neoplasm refers to an abnormal growth of cells that can be benign (non-cancerous) or malignant (cancerous). Neoplasms can occur in any part of the body and can affect various organs and tissues. The term "neoplasm" is often used interchangeably with "tumor," but while all tumors are neoplasms, not all neoplasms are tumors.

Types of Neoplasms

There are many different types of neoplasms, including:

1. Carcinomas: These are malignant tumors that arise in the epithelial cells lining organs and glands. Examples include breast cancer, lung cancer, and colon cancer.
2. Sarcomas: These are malignant tumors that arise in connective tissue, such as bone, cartilage, and fat. Examples include osteosarcoma (bone cancer) and soft tissue sarcoma.
3. Lymphomas: These are cancers of the immune system, specifically affecting the lymph nodes and other lymphoid tissues. Examples include Hodgkin lymphoma and non-Hodgkin lymphoma.
4. Leukemias: These are cancers of the blood and bone marrow that affect the white blood cells. Examples include acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL).
5. Melanomas: These are malignant tumors that arise in the pigment-producing cells called melanocytes. Examples include skin melanoma and eye melanoma.

Causes and Risk Factors of Neoplasms

The exact causes of neoplasms are not fully understood, but there are several known risk factors that can increase the likelihood of developing a neoplasm. These include:

1. Genetic predisposition: Some people may be born with genetic mutations that increase their risk of developing certain types of neoplasms.
2. Environmental factors: Exposure to certain environmental toxins, such as radiation and certain chemicals, can increase the risk of developing a neoplasm.
3. Infection: Some neoplasms are caused by viruses or bacteria. For example, human papillomavirus (HPV) is a common cause of cervical cancer.
4. Lifestyle factors: Factors such as smoking, excessive alcohol consumption, and a poor diet can increase the risk of developing certain types of neoplasms.
5. Family history: A person's risk of developing a neoplasm may be higher if they have a family history of the condition.

Signs and Symptoms of Neoplasms

The signs and symptoms of neoplasms can vary depending on the type of cancer and where it is located in the body. Some common signs and symptoms include:

1. Unusual lumps or swelling
2. Pain
3. Fatigue
4. Weight loss
5. Change in bowel or bladder habits
6. Unexplained bleeding
7. Coughing up blood
8. Hoarseness or a persistent cough
9. Changes in appetite or digestion
10. Skin changes, such as a new mole or a change in the size or color of an existing mole.

Diagnosis and Treatment of Neoplasms

The diagnosis of a neoplasm usually involves a combination of physical examination, imaging tests (such as X-rays, CT scans, or MRI scans), and biopsy. A biopsy involves removing a small sample of tissue from the suspected tumor and examining it under a microscope for cancer cells.

The treatment of neoplasms depends on the type, size, location, and stage of the cancer, as well as the patient's overall health. Some common treatments include:

1. Surgery: Removing the tumor and surrounding tissue can be an effective way to treat many types of cancer.
2. Chemotherapy: Using drugs to kill cancer cells can be effective for some types of cancer, especially if the cancer has spread to other parts of the body.
3. Radiation therapy: Using high-energy radiation to kill cancer cells can be effective for some types of cancer, especially if the cancer is located in a specific area of the body.
4. Immunotherapy: Boosting the body's immune system to fight cancer can be an effective treatment for some types of cancer.
5. Targeted therapy: Using drugs or other substances to target specific molecules on cancer cells can be an effective treatment for some types of cancer.

Prevention of Neoplasms

While it is not always possible to prevent neoplasms, there are several steps that can reduce the risk of developing cancer. These include:

1. Avoiding exposure to known carcinogens (such as tobacco smoke and radiation)
2. Maintaining a healthy diet and lifestyle
3. Getting regular exercise
4. Not smoking or using tobacco products
5. Limiting alcohol consumption
6. Getting vaccinated against certain viruses that are associated with cancer (such as human papillomavirus, or HPV)
7. Participating in screening programs for early detection of cancer (such as mammograms for breast cancer and colonoscopies for colon cancer)
8. Avoiding excessive exposure to sunlight and using protective measures such as sunscreen and hats to prevent skin cancer.

It's important to note that not all cancers can be prevented, and some may be caused by factors that are not yet understood or cannot be controlled. However, by taking these steps, individuals can reduce their risk of developing cancer and improve their overall health and well-being.

COX deficiency can present in various forms, including:

1. Leigh syndrome: A severe form of COX deficiency that typically becomes apparent during infancy or early childhood and is characterized by progressive loss of motor function, intellectual disability, seizures, and death in the first few years of life.
2. Late-onset COX deficiency: A milder form of the condition that may not become apparent until adulthood and can present with a range of symptoms such as muscle weakness, ataxia, and neuropathy.
3. COX deficiency with cognitive impairment: A rare form of the condition that is characterized by cognitive impairment, seizures, and other neurological symptoms.

Symptoms of COX deficiency can vary in severity and may include:

1. Muscle weakness
2. Muscle wasting
3. Ataxia (loss of coordination)
4. Neuropathy (nerve damage)
5. Seizures
6. Intellectual disability
7. Developmental delays
8. Vision and hearing loss
9. Optic atrophy (degeneration of the optic nerve)
10. Retinal degeneration

The diagnosis of COX deficiency is based on a combination of clinical findings, laboratory tests, and genetic analysis. Treatment for the condition typically involves managing symptoms and addressing any underlying complications. This may include:

1. Medications to control seizures and other neurological symptoms
2. Physical therapy to improve muscle strength and coordination
3. Occupational therapy to assist with daily activities
4. Speech therapy to address communication and swallowing difficulties
5. Vision and hearing aids as needed
6. Dietary supplements to manage any nutritional deficiencies
7. Other supportive measures as needed, such as respiratory support or feeding tubes.

It is important for individuals with COX deficiency to receive early and ongoing medical care from a team of healthcare professionals, including specialists in neurology, ophthalmology, and genetics. With appropriate management, many individuals with COX deficiency can lead active and fulfilling lives despite the challenges posed by the condition.

Dyskeratosis congenita is a rare genetic disorder that affects the bone marrow, skin, and other organs. It is characterized by a defect in the maturation of hematopoietic stem cells, leading to a triad of symptoms:

1. Poor immune function
2. Bone marrow failure
3. Skin changes (such as poikiloderma, telangiectasia, and pigmentary changes)

The disorder is caused by mutations in genes involved in hematopoiesis and DNA repair, leading to a decrease in the number of blood cells and an increased risk of infections, bleeding, and cancer. Treatment options for dyskeratosis congenita include bone marrow transplantation, immunosuppressive therapy, and supportive care to manage symptoms and prevent complications. The prognosis for the disorder is generally poor, with most patients dying in childhood or adolescence due to complications related to bone marrow failure and/or cancer.

The condition is caused by a variety of genetic mutations that can affect the development of the nervous system, muscles, or connective tissue. The symptoms of arthrogryposis can vary widely depending on the specific type and severity of the condition. They may include:

* Joint contractures: The joints become stiff and fixed in place, which can limit movement and cause deformities.
* Muscle weakness: The muscles may be weak or paralyzed, leading to difficulty moving the affected limbs.
* Delayed motor development: Children with arthrogryposis may experience delays in reaching developmental milestones such as sitting, standing, and walking.
* Limited range of motion: The joints may have a limited range of motion, making it difficult to move the affected limbs through their full range of motion.
* Muscle wasting: The muscles may waste away due to lack of use, leading to a weakened appearance.

There is no cure for arthrogryposis, but treatment options are available to help manage the symptoms and improve quality of life. These may include:

* Physical therapy: To maintain or improve muscle strength and range of motion.
* Occupational therapy: To assist with daily activities and fine motor skills.
* Surgery: To release contracted joints and improve mobility.
* Bracing and orthotics: To support weakened joints and improve posture.
* Medications: To manage pain and spasticity.

It is important to note that arthrogryposis is a complex condition, and the specific treatment plan will depend on the type and severity of the condition, as well as the individual needs of the patient. Early diagnosis and intervention are key to improving outcomes for individuals with arthrogryposis.

The exact cause of hypertelorism is not known, but it is thought to be related to genetic mutations that affect the development of the skull and face during fetal development. The condition can run in families, and there may be a higher risk of recurrence if there is a family history of hypertelorism or other similar conditions.

There are several distinct types of hypertelorism, including:

* Isolated hypertelorism: This is the most common type and is characterized by an abnormal distance between the orbits without any other facial anomalies.
* Syndromic hypertelorism: This type is associated with other congenital anomalies, such as cleft lip and palate, hearing loss, and intellectual disability.
* Familial hypertelorism: This type runs in families and may be associated with other genetic conditions.

There is no specific treatment for hypertelorism, but rather a multidisciplinary approach that includes:

* Monitoring and management of any associated conditions, such as hearing loss or intellectual disability.
* Orthodontic treatment to help align the teeth and improve the appearance of the smile.
* Ophthalmological monitoring to ensure proper eye care and vision development.
* Surgical intervention to correct any facial anomalies, such as cleft lip and palate, or to improve the appearance of the face.

The prognosis for individuals with hypertelorism varies depending on the severity of the condition and the presence of any associated anomalies. In general, early diagnosis and appropriate management can help improve the outcomes and quality of life for individuals with this condition.

1. Vision loss or blindness
2. Developmental delays and intellectual disability
3. Speech and language difficulties
4. Poor coordination and balance
5. Skeletal abnormalities such as short stature, short arms, and curved spine
6. Kidney problems
7. Hearing loss
8. Increased risk of infections
9. Cleft palate or other facial defects
10. Delayed puberty or absent menstruation in females

The syndrome is caused by mutations in the Bardet-Biedl genes, which are responsible for the development and function of the body's sensory and motor systems. It is inherited in an autosomal recessive pattern, meaning that a child must inherit two copies of the mutated gene - one from each parent - to develop the condition.

There is currently no cure for Bardet-Biedl Syndrome, but treatment and management options are available to help manage the symptoms and improve quality of life. These may include:

1. Vision aids such as glasses or contact lenses
2. Speech and language therapy
3. Physical therapy to improve coordination and balance
4. Occupational therapy to develop daily living skills
5. Medications to manage infections, seizures, or other complications
6. Surgery to correct physical abnormalities such as cleft palate or spinal deformities
7. Hormone replacement therapy for delayed puberty or absent menstruation in females.

The prognosis for individuals with Bardet-Biedl Syndrome varies depending on the severity of the symptoms and the presence of any additional health issues. With appropriate management and support, many individuals with the condition are able to lead fulfilling lives and achieve their goals. However, the syndrome can be associated with a higher risk of certain health complications, such as kidney disease or respiratory infections, which can impact life expectancy.

Some common examples of neurodegenerative diseases include:

1. Alzheimer's disease: A progressive loss of cognitive function, memory, and thinking skills that is the most common form of dementia.
2. Parkinson's disease: A disorder that affects movement, balance, and coordination, causing tremors, rigidity, and difficulty with walking.
3. Huntington's disease: An inherited condition that causes progressive loss of cognitive, motor, and psychiatric functions.
4. Amyotrophic lateral sclerosis (ALS): A disease that affects the nerve cells responsible for controlling voluntary muscle movement, leading to muscle weakness, paralysis, and eventually death.
5. Prion diseases: A group of rare and fatal disorders caused by misfolded proteins in the brain, leading to neurodegeneration and death.
6. Creutzfeldt-Jakob disease: A rare, degenerative, and fatal brain disorder caused by an abnormal form of a protein called a prion.
7. Frontotemporal dementia: A group of diseases that affect the front and temporal lobes of the brain, leading to changes in personality, behavior, and language.

Neurodegenerative diseases can be caused by a variety of factors, including genetics, age, lifestyle, and environmental factors. They are typically diagnosed through a combination of medical history, physical examination, laboratory tests, and imaging studies. Treatment options for neurodegenerative diseases vary depending on the specific condition and its underlying causes, but may include medications, therapy, and lifestyle changes.

Preventing or slowing the progression of neurodegenerative diseases is a major focus of current research, with various potential therapeutic strategies being explored, such as:

1. Stem cell therapies: Using stem cells to replace damaged neurons and restore brain function.
2. Gene therapies: Replacing or editing genes that are linked to neurodegenerative diseases.
3. Small molecule therapies: Developing small molecules that can slow or prevent the progression of neurodegenerative diseases.
4. Immunotherapies: Harnessing the immune system to combat neurodegenerative diseases.
5. Lifestyle interventions: Promoting healthy lifestyle choices, such as regular exercise and a balanced diet, to reduce the risk of developing neurodegenerative diseases.

In conclusion, neurodegenerative diseases are a complex and diverse group of disorders that can have a profound impact on individuals and society. While there is currently no cure for these conditions, research is providing new insights into their causes and potential treatments. By continuing to invest in research and developing innovative therapeutic strategies, we can work towards improving the lives of those affected by neurodegenerative diseases and ultimately finding a cure.

The primary symptom of CHS is a weakened immune system, which makes patients more susceptible to infections such as pneumonia and meningitis. Other common symptoms include:

* Easy bruising and bleeding
* Poor wound healing
* Recurring skin rashes
* Enlarged lymph nodes
* Joint pain and stiffness
* Vision loss or blindness

There is no cure for CHS, but bone marrow transplantation has been shown to be effective in improving the immune system and reducing the risk of complications. Treatment also includes antibiotics to prevent and treat infections, as well as other supportive therapies to manage symptoms such as joint pain and vision loss.

The prognosis for CHS is generally poor, with many patients dying before the age of 20 due to complications related to infection or organ failure. However, with early diagnosis and appropriate treatment, some patients have been able to survive into adulthood.

CHS is an autosomal recessive disorder, meaning that it is caused by mutations in both copies of the CHS1 gene. This means that children must inherit one mutated copy of the gene from each parent in order to develop the condition.

There are several other conditions that can cause similar symptoms to CHS, including:

* X-linked severe combined immunodeficiency (XSCID)
* Leukocyte adhesion deficiency (LAD)
* Chronic granulomatous disease (CGD)

It is important for healthcare providers to be aware of these conditions and to consider them in the differential diagnosis when evaluating patients with symptoms similar to those of CHS.

The term "chondrodysplasia" refers to a group of disorders that affect the development of cartilage and bone, while "punctata" means "spotted" or "speckled" in Latin. This refers to the characteristic punctate (small, dark spots) appearance of the skin and other tissues in individuals with CDP.

CDP is caused by mutations in genes that are involved in the formation and maintenance of cartilage and bone. The disorder typically affects both males and females equally, and the age of onset and severity of symptoms can vary widely. In addition to the characteristic physical features of CDP, individuals with this condition may also experience joint pain, hearing loss, and other health problems.

There is no cure for chondrodysplasia punctata, but treatment options are available to manage the associated symptoms and improve quality of life. These may include physical therapy, medication, and surgery. With appropriate care and support, individuals with CDP can lead fulfilling lives despite their condition.

The symptoms of oculocutaneous albinism (OCA) can vary in severity depending on the type of mutation and the extent of melanin reduction. Common symptoms include:

* Pale skin, hair, and eyes that are highly sensitive to the sun
* Vision problems such as nystagmus (involuntary eye movements), photophobia (sensitivity to light), and poor depth perception
* Increased risk of developing skin cancer due to lack of melanin
* Poor response to immunizations and increased risk of infections
* Delayed development of motor skills such as sitting, standing, and walking
* Delayed speech and language development
* Learning disabilities and intellectual disability in some cases

There is no cure for oculocutaneous albinism, but treatments can help manage the symptoms. These may include:

* Protective clothing and sunscreen to protect the skin from the sun's harmful rays
* Eyewear to correct vision problems
* Medication to reduce sensitivity to light and glare
* Regular check-ups with an ophthalmologist and dermatologist to monitor for signs of skin cancer and other complications
* Speech and language therapy to help with communication skills
* Physical therapy to improve motor skills and coordination
* Special education to address learning disabilities and intellectual disability

It is important for individuals with oculocutaneous albinism to receive early and accurate diagnosis, as well as ongoing medical care and support. With proper management, many individuals with this condition can lead fulfilling lives.

There are several types of cardiomyopathies, each with distinct characteristics and symptoms. Some of the most common forms of cardiomyopathy include:

1. Hypertrophic cardiomyopathy (HCM): This is the most common form of cardiomyopathy and is characterized by an abnormal thickening of the heart muscle, particularly in the left ventricle. HCM can lead to obstruction of the left ventricular outflow tract and can increase the risk of sudden death.
2. Dilated cardiomyopathy: This type of cardiomyopathy is characterized by a decrease in the heart's ability to pump blood effectively, leading to enlargement of the heart and potentially life-threatening complications such as congestive heart failure.
3. Restrictive cardiomyopathy: This type of cardiomyopathy is characterized by stiffness of the heart muscle, which makes it difficult for the heart to fill with blood. This can lead to shortness of breath and fatigue.
4. Left ventricular non-compaction (LVNC): This is a rare type of cardiomyopathy that occurs when the left ventricle does not properly compact, leading to reduced cardiac function and potentially life-threatening complications.
5. Cardiac amyloidosis: This is a condition in which abnormal proteins accumulate in the heart tissue, leading to stiffness and impaired cardiac function.
6. Right ventricular cardiomyopathy (RVCM): This type of cardiomyopathy is characterized by impaired function of the right ventricle, which can lead to complications such as pulmonary hypertension and heart failure.
7. Endocardial fibroelastoma: This is a rare type of cardiomyopathy that occurs when abnormal tissue grows on the inner lining of the heart, leading to reduced cardiac function and potentially life-threatening complications.
8. Cardiac sarcoidosis: This is a condition in which inflammatory cells accumulate in the heart, leading to impaired cardiac function and potentially life-threatening complications.
9. Hypertrophic cardiomyopathy (HCM): This is a condition in which the heart muscle thickens, leading to reduced cardiac function and potentially life-threatening complications such as arrhythmias and sudden death.
10. Hypokinetic left ventricular cardiomyopathy: This type of cardiomyopathy is characterized by decreased contraction of the left ventricle, leading to reduced cardiac function and potentially life-threatening complications such as heart failure.

It's important to note that some of these types of cardiomyopathy are more common in certain populations, such as hypertrophic cardiomyopathy being more common in young athletes. Additionally, some types of cardiomyopathy may have overlapping symptoms or co-occurring conditions, so it's important to work with a healthcare provider for an accurate diagnosis and appropriate treatment.

There are several types of genomic instability, including:

1. Chromosomal instability (CIN): This refers to changes in the number or structure of chromosomes, such as aneuploidy (having an abnormal number of chromosomes) or translocations (the movement of genetic material between chromosomes).
2. Point mutations: These are changes in a single base pair in the DNA sequence.
3. Insertions and deletions: These are changes in the number of base pairs in the DNA sequence, resulting in the insertion or deletion of one or more base pairs.
4. Genomic rearrangements: These are changes in the structure of the genome, such as chromosomal breaks and reunions, or the movement of genetic material between chromosomes.

Genomic instability can arise from a variety of sources, including environmental factors, errors during DNA replication and repair, and genetic mutations. It is often associated with cancer, as cancer cells have high levels of genomic instability, which can lead to the development of resistance to chemotherapy and radiation therapy.

Research into genomic instability has led to a greater understanding of the mechanisms underlying cancer and other diseases, and has also spurred the development of new therapeutic strategies, such as targeted therapies and immunotherapies.

In summary, genomic instability is a key feature of cancer cells and is associated with various diseases, including cancer, neurodegenerative disorders, and aging. It can arise from a variety of sources and is the subject of ongoing research in the field of molecular biology.

Symptoms of heat stroke may include:

* High body temperature (usually above 104°F)
* Confusion or altered mental state
* Slurred speech
* Seizures or convulsions
* Dry, flushed skin with no sweating
* Rapid heartbeat
* Shallow breathing
* Nausea and vomiting

If you suspect someone has heat stroke, it is important to seek medical attention immediately. Treatment typically involves moving the person to a cooler location, removing excess clothing, and providing cool liquids to drink. In severe cases, hospitalization may be necessary to monitor and treat the condition.

Prevention is key in avoiding heat stroke, so it is important to take precautions during hot weather such as:

* Staying in air-conditioned spaces when possible
* Wearing lightweight, loose-fitting clothing
* Avoiding strenuous activity during the hottest part of the day (usually between 11am and 3pm)
* Drinking plenty of water to stay hydrated
* Taking regular breaks in shaded or cool areas
* Avoiding alcohol and caffeine, which can exacerbate dehydration.

By understanding the definition of heat stroke and taking preventative measures, you can help protect yourself and others from this potentially life-threatening condition.

Carcinogenesis is the process by which normal cells are transformed into cancer cells. This complex process involves a series of genetic and molecular changes that can take place over a long period of time. The term "carcinogenesis" is derived from the Greek words "carcinoma," meaning cancer, and "genesis," meaning origin or creation.

Carcinogenesis is a multistep process that involves several stages, including:

1. initiation: This stage involves the activation of oncogenes or the inactivation of tumor suppressor genes, leading to the formation of precancerous cells.
2. promotion: In this stage, the precancerous cells undergo further changes that allow them to grow and divide uncontrollably.
3. progression: This stage is characterized by the spread of cancer cells to other parts of the body (metastasis).

The process of carcinogenesis is influenced by a variety of factors, including genetics, environmental factors, and lifestyle choices. Some of the known risk factors for carcinogenesis include:

1. tobacco use
2. excessive alcohol consumption
3. exposure to certain chemicals and radiation
4. obesity and poor diet
5. lack of physical activity
6. certain viral infections

Understanding the process of carcinogenesis is important for developing effective cancer prevention and treatment strategies. By identifying the early stages of carcinogenesis, researchers may be able to develop interventions that can prevent or reverse the process before cancer develops.

Here are some key points to define sepsis:

1. Inflammatory response: Sepsis is characterized by an excessive and uncontrolled inflammatory response to an infection. This can lead to tissue damage and organ dysfunction.
2. Systemic symptoms: Patients with sepsis often have systemic symptoms such as fever, chills, rapid heart rate, and confusion. They may also experience nausea, vomiting, and diarrhea.
3. Organ dysfunction: Sepsis can cause dysfunction in multiple organs, including the lungs, kidneys, liver, and heart. This can lead to organ failure and death if not treated promptly.
4. Infection source: Sepsis is usually caused by a bacterial infection, but it can also be caused by fungal or viral infections. The infection can be localized or widespread, and it can affect different parts of the body.
5. Severe sepsis: Severe sepsis is a more severe form of sepsis that is characterized by severe organ dysfunction and a higher risk of death. Patients with severe sepsis may require intensive care unit (ICU) admission and mechanical ventilation.
6. Septic shock: Septic shock is a life-threatening condition that occurs when there is severe circulatory dysfunction due to sepsis. It is characterized by hypotension, vasopressor use, and organ failure.

Early recognition and treatment of sepsis are critical to preventing serious complications and improving outcomes. The Sepsis-3 definition is widely used in clinical practice to diagnose sepsis and severe sepsis.

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At the molecular level, the mechanisms underlying exosome biogenesis and uptake are far from being understood. Recent work has ... highlighted the critical role for the small intracellular adaptor protein syntenin in the biogenesis of a subset of exosomes ... Syntenin: Key player in cancer exosome biogenesis and uptake?. Cell Adhesion and Migration, 2017, 11 (2), pp.124-126. ⟨10.1080/ ... At the molecular level, the mechanisms underlying exosome biogenesis and uptake are far from being understood. Recent work has ...
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Lysosomal biogenesis in storage disorders is shown to be a regulated process which is partially controlled at, or prior to, the ... Lysosomal biogenesis is an orchestration of the structural and functional elements of the lysosome to form an integrated ... We have investigated lysosomal biogenesis during the formation and dissipation of storage vacuoles in two model systems. One ... Although lysosomal proteins were differentially regulated, the coordination of these events in lysosomal biogenesis would ...
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Here we investigate the effects of Δ9-THC and pioglitazone on mitochondrial biogenesis and oxidative stress. Differentiated SH- ... activation can result in transcription of proteins involved in oxidative stress defence and mitochondrial biogenesis which ... tetrahydrocannabinol protects against MPP+ toxicity in SH-SY5Y cells by restoring proteins involved in mitochondrial biogenesis ...
The genetics of murine skeletal muscle biogenesis. Team: Stem Cells And Development ...
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β-catenin controls mitochondrial biogenesis. (A) Staining in live imaging of MCF-7 shCTR and MCF-7 shβcat mitochondria p.15 ... biogenesis transcriptional factors PGC1α, TFAM, and NRF1 observed in shβcat cells by Real time PCR. Our data points to β- ... Mitochondrial Biogenesis and Lipid. Metabolism in Breast Cancer Cells. Daniele Vergara1, 2 †, Eleonora Stanca1, 2 †, Flora ... The role of lipids in the biogenesis of integral membrane proteins. Gaigg B, Toulmay A, Schneiter R (2006) Very long-chain ...
Evolution of Fe/S cluster biogenesis in the anaerobic parasite Blastocystis. Proceedings of the National Academy of Sciences, ...
Multiple haem lyase genes indicate substrate specificity in cytochrome c biogenesis. Biochemical Society Transactions, 34. pp. ...
Lipoproteins in Gram-negative bacteria: new insights into their biogenesis, subcellular targeting and functional roles. ... Lipoproteins in Gram-negative bacteria: new insights into their biogenesis, subcellular ta ...
Biogenesis of synaptic vesicle-like structures in a pheochromocytoma cell line PC-12. In: Journal of Cell Biology. 1990 ; Vol. ... Biogenesis of synaptic vesicle-like structures in a pheochromocytoma cell line PC-12. Journal of Cell Biology. 1990;110(5):1693 ... Biogenesis of synaptic vesicle-like structures in a pheochromocytoma cell line PC-12. / Clift-OGrady, L.; Linstedt, A. D.; ... Clift-OGrady, L., Linstedt, A. D., Lowe, A. W., Grote, E., & Kelly, R. B. (1990). Biogenesis of synaptic vesicle-like ...
Fetal circulating human resistin increases in diabetes during pregnancy and impairs placental mitochondrial biogenesis. Mol Med ... Fetal circulating human resistin increases in diabetes during pregnancy and impairs placental mitochondrial biogenesis. ... Fetal circulating human resistin increases in diabetes during pregnancy and impairs placental mitochondrial biogenesis. ...
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DOI: http://dx.doi.org/10.31258/biogenesis.19.1.43-52 Refbacks. *Saat ini tidak ada refbacks. ...

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