The complete absence, or (loosely) the paucity, of gaseous or dissolved elemental oxygen in a given place or environment. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Life or metabolic reactions occurring in an environment containing oxygen.
Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
Organic compounds that contain two nitro groups attached to a phenol.
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.
An enzyme that catalyzes the oxidation of nitrite to nitrate. It is a cytochrome protein that contains IRON and MOLYBDENUM.
Inorganic or organic salts and esters of nitric acid. These compounds contain the NO3- radical.
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.
Oxidoreductases that are specific for the reduction of NITRATES.
Proteins found in any species of bacterium.
Derivatives of formic acids. Included under this heading are a broad variety of acid forms, salts, esters, and amides that are formed with a single carbon carboxy group.
Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.
Proteins obtained from ESCHERICHIA COLI.
Inorganic salts of HYDROGEN CYANIDE containing the -CN radical. The concept also includes isocyanides. It is distinguished from NITRILES, which denotes organic compounds containing the -CN radical.
Anaerobic degradation of GLUCOSE or other organic nutrients to gain energy in the form of ATP. End products vary depending on organisms, substrates, and enzymatic pathways. Common fermentation products include ETHANOL and LACTIC ACID.
A ferredoxin-containing enzyme that catalyzes the COENZYME A-dependent oxidative decarboxylation of PYRUVATE to acetyl-COENZYME A and CARBON DIOXIDE.
The functional hereditary units of BACTERIA.
Flavoproteins that catalyze reversibly the reduction of carbon dioxide to formate. Many compounds can act as acceptors, but the only physiologically active acceptor is NAD. The enzymes are active in the fermentation of sugars and other compounds to carbon dioxide and are the key enzymes in obtaining energy when bacteria are grown on formate as the main carbon source. They have been purified from bovine blood. EC 1.2.1.2.
A species of GREEN ALGAE. Delicate, hairlike appendages arise from the flagellar surface in these organisms.
An enzyme found in bacteria. It catalyzes the reduction of FERREDOXIN and other substances in the presence of molecular hydrogen and is involved in the electron transport of bacterial photosynthesis.
In bacteria, a group of metabolically related genes, with a common promoter, whose transcription into a single polycistronic MESSENGER RNA is under the control of an OPERATOR REGION.
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).
The genetic unit consisting of three structural genes, an operator and a regulatory gene. The regulatory gene controls the synthesis of the three structural genes: BETA-GALACTOSIDASE and beta-galactoside permease (involved with the metabolism of lactose), and beta-thiogalactoside acetyltransferase.
A toxic dye, chemically related to trinitrophenol (picric acid), used in biochemical studies of oxidative processes where it uncouples oxidative phosphorylation. It is also used as a metabolic stimulant. (Stedman, 26th ed)
A group of enzymes that catalyzes the hydrolysis of terminal, non-reducing beta-D-galactose residues in beta-galactosides. Deficiency of beta-Galactosidase A1 may cause GANGLIOSIDOSIS, GM1.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)
The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
A serotype of Salmonella enterica that is a frequent agent of Salmonella gastroenteritis in humans. It also causes PARATYPHOID FEVER.
An antibiotic substance produced by Streptomyces species. It inhibits mitochondrial respiration and may deplete cellular levels of ATP. Antimycin A1 has been used as a fungicide, insecticide, and miticide. (From Merck Index, 12th ed)
A species of rod-shaped bacteria that is a common soil saprophyte. Its spores are widespread and multiplication has been observed chiefly in foods. Contamination may lead to food poisoning.
The chemical reactions that occur within the cells, tissues, or an organism. These processes include both the biosynthesis (ANABOLISM) and the breakdown (CATABOLISM) of organic materials utilized by the living organism.
The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
A proton ionophore. It is commonly used as an uncoupling agent and inhibitor of photosynthesis because of its effects on mitochondrial and chloroplast membranes.
Genes which regulate or circumscribe the activity of other genes; specifically, genes which code for PROTEINS or RNAs which have GENE EXPRESSION REGULATION functions.
A metallic element with the atomic symbol Mo, atomic number 42, and atomic weight 95.94. It is an essential trace element, being a component of the enzymes xanthine oxidase, aldehyde oxidase, and nitrate reductase. (From Dorland, 27th ed)
A flavoprotein containing oxidoreductase that catalyzes the dehydrogenation of SUCCINATE to fumarate. In most eukaryotic organisms this enzyme is a component of mitochondrial electron transport complex II.
The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)
The rate dynamics in chemical or physical systems.
Tools or devices for generating products using the synthetic or chemical conversion capacity of a biological system. They can be classical fermentors, cell culture perfusion systems, or enzyme bioreactors. For production of proteins or enzymes, recombinant microorganisms such as bacteria, mammalian cells, or insect or plant cells are usually chosen.
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 primary source of energy for living organisms. It is naturally occurring and is found in fruits and other parts of plants in its free state. It is used therapeutically in fluid and nutrient replacement.
The 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)
DNA sequences which are recognized (directly or indirectly) and bound by a DNA-dependent RNA polymerase during the initiation of transcription. Highly conserved sequences within the promoter include the Pribnow box in bacteria and the TATA BOX in eukaryotes.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in enzyme synthesis.
Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control of gene action in fungi.
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.
Deoxyribonucleic acid that makes up the genetic material of bacteria.
The non-genetic biological changes of an organism in response to challenges in its ENVIRONMENT.
Salts or esters of LACTIC ACID containing the general formula CH3CHOHCOOR.
Total mass of all the organisms of a given type and/or in a given area. (From Concise Dictionary of Biology, 1990) It includes the yield of vegetative mass produced from any given crop.
A metabolic process that converts GLUCOSE into two molecules of PYRUVIC ACID through a series of enzymatic reactions. Energy generated by this process is conserved in two molecules of ATP. Glycolysis is the universal catabolic pathway for glucose, free glucose, or glucose derived from complex CARBOHYDRATES, such as GLYCOGEN and STARCH.
An absence of warmth or heat or a temperature notably below an accustomed norm.
Enzymes catalyzing the transfer of an acetyl group, usually from acetyl coenzyme A, to another compound. EC 2.3.1.
A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in ALCOHOLIC BEVERAGES.
The chemical reactions involved in the production and utilization of various forms of energy in cells.
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.
Techniques used in studying bacteria.
A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
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.
A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.
Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.
Spectrophotometry in the infrared region, usually for the purpose of chemical analysis through measurement of absorption spectra associated with rotational and vibrational energy levels of molecules. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
That portion of the electromagnetic spectrum in the visible, ultraviolet, and infrared range.
Inorganic salts of phosphoric acid.
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)
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.
Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.
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.

Denitrifying Pseudomonas aeruginosa: some parameters of growth and active transport. (1/4712)

Optimal cell yield of Pseudomonas aeruginosa grown under denitrifying conditions was obtained with 100 mM nitrate as the terminal electron acceptor, irrespective of the medium used. Nitrite as the terminal electron acceptor supported poor denitrifying growth when concentrations of less than 15 mM, but not higher, were used, apparently owing to toxicity exerted by nitrite. Nitrite accumulated in the medium during early exponential phase when nitrate was the terminal electron acceptor and then decreased to extinction before midexponential phase. The maximal rate of glucose and gluconate transport was supported by 1 mM nitrate or nitrite as the terminal electron acceptor under anaerobic conditions. The transport rate was greater with nitrate than with nitrite as the terminal electron acceptor, but the greatest transport rate was observed under aerobic conditions with oxygen as the terminal electron acceptor. When P. aeruginosa was inoculated into a denitrifying environment, nitrate reductase was detected after 3 h of incubation, nitrite reductase was detected after another 4 h of incubation, and maximal nitrate and nitrite reductase activities peaked together during midexponential phase. The latter coincided with maximal glucose transport activity.  (+info)

Molecular characterization of the nitrite-reducing system of Staphylococcus carnosus. (2/4712)

Characterization of a nitrite reductase-negative Staphylococcus carnosus Tn917 mutant led to the identification of the nir operon, which encodes NirBD, the dissimilatory NADH-dependent nitrite reductase; SirA, the putative oxidase and chelatase, and SirB, the uroporphyrinogen III methylase, both of which are necessary for biosynthesis of the siroheme prosthetic group; and NirR, which revealed no convincing similarity to proteins with known functions. We suggest that NirR is essential for nir promoter activity. In the absence of NirR, a weak promoter upstream of sirA seems to drive transcription of sirA, nirB, nirD, and sirB in the stationary-growth phase. In primer extension experiments one predominant and several weaker transcription start sites were identified in the nir promoter region. Northern blot analyses indicated that anaerobiosis and nitrite are induction factors of the nir operon: cells grown aerobically with nitrite revealed small amounts of full-length transcript whereas cells grown anaerobically with or without nitrite showed large amounts of full-length transcript. Although a transcript is detectable, no nitrite reduction occurs in cells grown aerobically with nitrite, indicating an additional oxygen-controlled step at the level of translation, enzyme folding, assembly, or insertion of prosthetic groups. The nitrite-reducing activity expressed during anaerobiosis is switched off reversibly when the oxygen tension increases, most likely due to competition for electrons with the aerobic respiratory chain. Another gene, nirC, is located upstream of the nir operon. nirC encodes a putative integral membrane-spanning protein of unknown function. A nirC mutant showed no distinct phenotype.  (+info)

Unusual ribulose 1,5-bisphosphate carboxylase/oxygenase of anoxic Archaea. (3/4712)

The predominant pool of organic matter on earth is derived from the biological reduction and assimilation of carbon dioxide gas, catalyzed primarily by the enzyme ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO). By virtue of its capacity to use molecular oxygen as an alternative and competing gaseous substrate, the catalytic efficiency of RubisCO and the enzyme's ability to assimilate CO2 may be severely limited, with consequent environmental and agricultural effects. Recent genomic sequencing projects, however, have identified putative RubisCO genes from anoxic Archaea. In the present study, these potential RubisCO sequences, from Methanococcus jannaschii and Archaeoglobus fulgidus, were analyzed in order to ascertain whether such sequences might encode functional proteins. We also report the isolation and properties of recombinant RubisCO using sequences obtained from the obligately anaerobic hyperthermophilic methanogen M. jannaschii. This is the first description of an archaeal RubisCO sequence; this study also represents the initial characterization of a RubisCO molecule that has evolved in the absence of molecular oxygen. The enzyme was shown to be a homodimer whose deduced sequence, along with other recently obtained archaeal RubisCO sequences, differs substantially from those of known RubisCO molecules. The recombinant M. jannaschii enzyme has a somewhat low, but reasonable kcat, however, unlike previously isolated RubisCO molecules, this enzyme is very oxygen sensitive yet it is stable to hyperthermal temperatures and catalyzes the formation of the expected carboxylation product. Despite inhibition by oxygen, this unusual RubisCO still catalyzes a weak yet demonstrable oxygenase activity, with perhaps the lowest capacity for CO2/O2 discrimination ever encountered for any RubisCO.  (+info)

Metal-catalyzed oxidation of phenylalanine-sensitive 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase from Escherichia coli: inactivation and destabilization by oxidation of active-site cysteines. (4/4712)

The in vitro instability of the phenylalanine-sensitive 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase [DAHPS(Phe)] from Escherichia coli has been found to be due to a metal-catalyzed oxidation mechanism. DAHPS(Phe) is one of three differentially feedback-regulated isoforms of the enzyme which catalyzes the first step of aromatic biosynthesis, the formation of DAHP from phosphoenolpyruvate and D-erythrose-4-phosphate. The activity of the apoenzyme decayed exponentially, with a half-life of about 1 day at room temperature, and the heterotetramer slowly dissociated to the monomeric state. The enzyme was stabilized by the presence of phosphoenolpyruvate or EDTA, indicating that in the absence of substrate, a trace metal(s) was the inactivating agent. Cu2+ and Fe2+, but none of the other divalent metals that activate the enzyme, greatly accelerated the rate of inactivation and subunit dissociation. Both anaerobiosis and the addition of catalase significantly reduced Cu2+-catalyzed inactivation. In the spontaneously inactivated enzyme, there was a net loss of two of the seven thiols per subunit; this value increased with increasing concentrations of added Cu2+. Dithiothreitol completely restored the enzymatic activity and the two lost thiols in the spontaneously inactivated enzyme but was only partially effective in reactivation of the Cu2+-inactivated enzyme. Mutant enzymes with conservative replacements at either of the two active-site cysteines, Cys61 or Cys328, were insensitive to the metal attack. Peptide mapping of the Cu2+-inactivated enzyme revealed a disulfide linkage between these two cysteine residues. All results indicate that DAHPS(Phe) is a metal-catalyzed oxidation system wherein bound substrate protects active-site residues from oxidative attack catalyzed by bound redox metal cofactor. A mechanism of inactivation of DAHPS is proposed that features a metal redox cycle that requires the sequential oxidation of its two active-site cysteines.  (+info)

Anaerobic oxidation of o-xylene, m-xylene, and homologous alkylbenzenes by new types of sulfate-reducing bacteria. (5/4712)

Various alkylbenzenes were depleted during growth of an anaerobic, sulfate-reducing enrichment culture with crude oil as the only source of organic substrates. From this culture, two new types of mesophilic, rod-shaped sulfate-reducing bacteria, strains oXyS1 and mXyS1, were isolated with o-xylene and m-xylene, respectively, as organic substrates. Sequence analyses of 16S rRNA genes revealed that the isolates affiliated with known completely oxidizing sulfate-reducing bacteria of the delta subclass of the class Proteobacteria. Strain oXyS1 showed the highest similarities to Desulfobacterium cetonicum and Desulfosarcina variabilis (similarity values, 98.4 and 98.7%, respectively). Strain mXyS1 was less closely related to known species, the closest relative being Desulfococcus multivorans (similarity value, 86.9%). Complete mineralization of o-xylene and m-xylene was demonstrated in quantitative growth experiments. Strain oXyS1 was able to utilize toluene, o-ethyltoluene, benzoate, and o-methylbenzoate in addition to o-xylene. Strain mXyS1 oxidized toluene, m-ethyltoluene, m-isoproyltoluene, benzoate, and m-methylbenzoate in addition to m-xylene. Strain oXyS1 did not utilize m-alkyltoluenes, whereas strain mXyS1 did not utilize o-alkyltoluenes. Like the enrichment culture, both isolates grew anaerobically on crude oil with concomitant reduction of sulfate to sulfide.  (+info)

Immobilization patterns and dynamics of acetate-utilizing methanogens immobilized in sterile granular sludge in upflow anaerobic sludge blanket reactors. (6/4712)

Sterile granular sludge was inoculated with either Methanosarcina mazeii S-6, Methanosaeta concilii GP-6, or both species in acetate-fed upflow anaerobic sludge blanket (UASB) reactors to investigate the immobilization patterns and dynamics of aceticlastic methanogens in granular sludge. After several months of reactor operation, the methanogens were immobilized, either separately or together. The fastest immobilization was observed in the reactor containing M. mazeii S-6. The highest effluent concentration of acetate was observed in the reactor with only M. mazeii S-6 immobilized, while the lowest effluent concentration of acetate was observed in the reactor where both types of methanogens were immobilized together. No changes were observed in the kinetic parameters (Ks and mumax) of immobilized M. concilii GP-6 or M. mazeii S-6 compared with suspended cultures, indicating that immobilization does not affect the growth kinetics of these methanogens. An enzyme-linked immunosorbent assay using polyclonal antibodies against either M. concilii GP-6 or M. mazeii S-6 showed significant variations in the two methanogenic populations in the different reactors. Polyclonal antibodies were further used to study the spatial distribution of the two methanogens. M. concilii GP-6 was immobilized only on existing support material without any specific pattern. M. mazeii S-6, however, showed a different immobilization pattern: large clumps were formed when the concentration of acetate was high, but where the acetate concentration was low this strain was immobilized on support material as single cells or small clumps. The data clearly show that the two aceticlastic methanogens immobilize differently in UASB systems, depending on the conditions found throughout the UASB reactor.  (+info)

Anaerobic degradation of phthalate isomers by methanogenic consortia. (7/4712)

Three methanogenic enrichment cultures, grown on ortho-phthalate, iso-phthalate, or terephthalate were obtained from digested sewage sludge or methanogenic granular sludge. Cultures grown on one of the phthalate isomers were not capable of degrading the other phthalate isomers. All three cultures had the ability to degrade benzoate. Maximum specific growth rates (microseconds max) and biomass yields (YXtotS) of the mixed cultures were determined by using both the phthalate isomers and benzoate as substrates. Comparable values for these parameters were found for all three cultures. Values for microseconds max and YXtotS were higher for growth on benzoate compared to the phthalate isomers. Based on measured and estimated values for the microbial yield of the methanogens in the mixed culture, specific yields for the phthalate and benzoate fermenting organisms were calculated. A kinetic model, involving three microbial species, was developed to predict intermediate acetate and hydrogen accumulation and the final production of methane. Values for the ratio of the concentrations of methanogenic organisms, versus the phthalate isomer and benzoate fermenting organisms, and apparent half-saturation constants (KS) for the methanogens were calculated. By using this combination of measured and estimated parameter values, a reasonable description of intermediate accumulation and methane formation was obtained, with the initial concentration of phthalate fermenting organisms being the only variable. The energetic efficiency for growth of the fermenting organisms on the phthalate isomers was calculated to be significantly smaller than for growth on benzoate.  (+info)

The role of benzoate in anaerobic degradation of terephthalate. (8/4712)

The effects of acetate, benzoate, and periods without substrate on the anaerobic degradation of terephthalate (1, 4-benzene-dicarboxylate) by a syntrophic methanogenic culture were studied. The culture had been enriched on terephthalate and was capable of benzoate degradation without a lag phase. When incubated with a mixture of benzoate and terephthalate, subsequent degradation with preference for benzoate was observed. Both benzoate and acetate inhibited the anaerobic degradation of terephthalate. The observed inhibition is partially irreversible, resulting in a decrease (or even a complete loss) of the terephthalate-degrading activity after complete degradation of benzoate or acetate. Irreversible inhibition was characteristic for terephthalate degradation only because the inhibition of benzoate degradation by acetate could well be described by reversible noncompetitive product inhibition. Terephthalate degradation was furthermore irreversibly inhibited by periods without substrate of only a few hours. The inhibition of terephthalate degradation due to periods without substrate could be overcome through incubation of the culture with a mixture of benzoate and terephthalate. In this case no influence of a period without substrate was observed. Based on these observations it is postulated that decarboxylation of terephthalate, resulting in the formation of benzoate, is strictly dependent on the concomitant fermentation of benzoate. In the presence of higher concentrations of benzoate, however, benzoate is the favored substrate over terephthalate, and the culture loses its ability to degrade terephthalate. In order to overcome the inhibition of terephthalate degradation by benzoate and acetate, a two-stage reactor system is suggested for the treatment of wastewater generated during terephthalic acid production.  (+info)

Anaerobiosis is a state in which an organism or a portion of an organism is able to live and grow in the absence of molecular oxygen (O2). In biological contexts, "anaerobe" refers to any organism that does not require oxygen for growth, and "aerobe" refers to an organism that does require oxygen for growth.

There are two types of anaerobes: obligate anaerobes, which cannot tolerate the presence of oxygen and will die if exposed to it; and facultative anaerobes, which can grow with or without oxygen but prefer to grow in its absence. Some organisms are able to switch between aerobic and anaerobic metabolism depending on the availability of oxygen, a process known as "facultative anaerobiosis."

Anaerobic respiration is a type of metabolic process that occurs in the absence of molecular oxygen. In this process, organisms use alternative electron acceptors other than oxygen to generate energy through the transfer of electrons during cellular respiration. Examples of alternative electron acceptors include nitrate, sulfate, and carbon dioxide.

Anaerobic metabolism is less efficient than aerobic metabolism in terms of energy production, but it allows organisms to survive in environments where oxygen is not available or is toxic. Anaerobic bacteria are important decomposers in many ecosystems, breaking down organic matter and releasing nutrients back into the environment. In the human body, anaerobic bacteria can cause infections and other health problems if they proliferate in areas with low oxygen levels, such as the mouth, intestines, or deep tissue wounds.

Aerobiosis is the process of living, growing, and functioning in the presence of oxygen. It refers to the metabolic processes that require oxygen to break down nutrients and produce energy in cells. This is in contrast to anaerobiosis, which is the ability to live and grow in the absence of oxygen.

In medical terms, aerobiosis is often used to describe the growth of microorganisms, such as bacteria and fungi, that require oxygen to survive and multiply. These organisms are called aerobic organisms, and they play an important role in many biological processes, including decomposition and waste breakdown.

However, some microorganisms are unable to grow in the presence of oxygen and are instead restricted to environments where oxygen is absent or limited. These organisms are called anaerobic organisms, and their growth and metabolism are referred to as anaerobiosis.

Gene expression regulation in bacteria refers to the complex cellular processes that control the production of proteins from specific genes. This regulation allows bacteria to adapt to changing environmental conditions and ensure the appropriate amount of protein is produced at the right time.

Bacteria have a variety of mechanisms for regulating gene expression, including:

1. Operon structure: Many bacterial genes are organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule. The expression of these genes can be coordinately regulated by controlling the transcription of the entire operon.
2. Promoter regulation: Transcription is initiated at promoter regions upstream of the gene or operon. Bacteria have regulatory proteins called sigma factors that bind to the promoter and recruit RNA polymerase, the enzyme responsible for transcribing DNA into RNA. The binding of sigma factors can be influenced by environmental signals, allowing for regulation of transcription.
3. Attenuation: Some operons have regulatory regions called attenuators that control transcription termination. These regions contain hairpin structures that can form in the mRNA and cause transcription to stop prematurely. The formation of these hairpins is influenced by the concentration of specific metabolites, allowing for regulation of gene expression based on the availability of those metabolites.
4. Riboswitches: Some bacterial mRNAs contain regulatory elements called riboswitches that bind small molecules directly. When a small molecule binds to the riboswitch, it changes conformation and affects transcription or translation of the associated gene.
5. CRISPR-Cas systems: Bacteria use CRISPR-Cas systems for adaptive immunity against viruses and plasmids. These systems incorporate short sequences from foreign DNA into their own genome, which can then be used to recognize and cleave similar sequences in invading genetic elements.

Overall, gene expression regulation in bacteria is a complex process that allows them to respond quickly and efficiently to changing environmental conditions. Understanding these regulatory mechanisms can provide insights into bacterial physiology and help inform strategies for controlling bacterial growth and behavior.

Oxygen is a colorless, odorless, tasteless gas that constitutes about 21% of the earth's atmosphere. It is a crucial element for human and most living organisms as it is vital for respiration. Inhaled oxygen enters the lungs and binds to hemoglobin in red blood cells, which carries it to tissues throughout the body where it is used to convert nutrients into energy and carbon dioxide, a waste product that is exhaled.

Medically, supplemental oxygen therapy may be provided to patients with conditions such as chronic obstructive pulmonary disease (COPD), pneumonia, heart failure, or other medical conditions that impair the body's ability to extract sufficient oxygen from the air. Oxygen can be administered through various devices, including nasal cannulas, face masks, and ventilators.

Dinitrophenols (DNP) are a class of chemical compounds that contain two nitro groups (-NO2) attached to a phenol group. Dinitrophenols have been used in the past as industrial dyes, wood preservatives, and pesticides. However, they have also been misused as weight loss supplements due to their ability to increase metabolic rate and cause weight loss.

The use of DNP for weight loss is dangerous and has been linked to several fatalities. DNP works by disrupting the normal functioning of the mitochondria in cells, which are responsible for producing energy. This disruption causes an increase in metabolic rate, leading to a rapid breakdown of fat and carbohydrates, and ultimately weight loss. However, this increased metabolism can also produce excessive heat, leading to hyperthermia, dehydration, and damage to organs such as the heart, liver, and kidneys.

Due to their potential for serious harm, DNP-containing products are banned in many countries, including the United States. Medical professionals should be aware of the dangers associated with DNP use and advise patients accordingly.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Nitrate reductase is an enzyme that catalyzes the reduction of nitrate (NO3-) to nitrite (NO2-). It is widely distributed in nature and plays a crucial role in the nitrogen cycle, particularly in the process of nitrate assimilation by plants, fungi, and some bacteria.

In plants, nitrate reductase is primarily located in the cytoplasm and chloroplasts of plant cells. It requires reduced forms of nicotinamide adenine dinucleotide phosphate (NADPH) or flavin adenine dinucleotide (FADH2) as electron donors to facilitate the reduction of nitrate to nitrite.

The reaction catalyzed by nitrate reductase can be summarized as follows:
NO3- + NAD(P)H + H+ -> NO2- + NAD(P)+ + H2O

It is worth noting that there are different types of nitrate reductases, each with distinct properties and functions. For example, some nitrate reductases require molybdenum cofactor as a prosthetic group for their catalytic activity, while others do not. Additionally, some nitrate reductases are membrane-bound, while others are soluble enzymes.

Overall, nitrate reductase is an essential enzyme in the global nitrogen cycle and has significant implications for agriculture, environmental science, and microbiology.

Nitrates are chemical compounds that consist of a nitrogen atom bonded to three oxygen atoms (NO3-). In the context of medical science, nitrates are often discussed in relation to their use as medications or their presence in food and water.

As medications, nitrates are commonly used to treat angina (chest pain) caused by coronary artery disease. Nitrates work by relaxing and widening blood vessels, which improves blood flow and reduces the workload on the heart. Some examples of nitrate medications include nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate.

In food and water, nitrates are naturally occurring compounds that can be found in a variety of vegetables, such as spinach, beets, and lettuce. They can also be present in fertilizers and industrial waste, which can contaminate groundwater and surface water sources. While nitrates themselves are not harmful, they can be converted into potentially harmful compounds called nitrites under certain conditions, particularly in the digestive system of young children or in the presence of bacteria such as those found in unpasteurized foods. Excessive levels of nitrites can react with hemoglobin in the blood to form methemoglobin, which cannot transport oxygen effectively and can lead to a condition called methemoglobinemia.

Iron-sulfur proteins are a group of metalloproteins that contain iron and sulfur atoms in their active centers. These clusters of iron and sulfur atoms, also known as iron-sulfur clusters, can exist in various forms, including Fe-S, 2Fe-2S, 3Fe-4S, and 4Fe-4S structures. The iron atoms are coordinated to the protein through cysteine residues, while the sulfur atoms can be in the form of sulfide (S2-) or sulfane (-S-).

These proteins play crucial roles in many biological processes, such as electron transfer, redox reactions, and enzyme catalysis. They are found in various organisms, from bacteria to humans, and are involved in a wide range of cellular functions, including energy metabolism, photosynthesis, nitrogen fixation, and DNA repair.

Iron-sulfur proteins can be classified into several categories based on their structure and function, such as ferredoxins, Rieske proteins, high-potential iron-sulfur proteins (HiPIPs), and radical SAM enzymes. Dysregulation or mutations in iron-sulfur protein genes have been linked to various human diseases, including neurodegenerative disorders, cancer, and mitochondrial disorders.

Nitrate reductases are a group of enzymes that catalyze the reduction of nitrate (NO3-) to nitrite (NO2-). This process is an essential part of the nitrogen cycle, where nitrate serves as a terminal electron acceptor in anaerobic respiration for many bacteria and archaea. In plants, this enzyme plays a crucial role in nitrogen assimilation by reducing nitrate to ammonium (NH4+), which can then be incorporated into organic compounds. Nitrate reductases require various cofactors, such as molybdenum, heme, and/or FAD, for their activity. There are three main types of nitrate reductases: membrane-bound (which use menaquinol as an electron donor), cytoplasmic (which use NADH or NADPH as an electron donor), and assimilatory (which also use NADH or NADPH as an electron donor).

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

I'm sorry for any confusion, but "Formates" is not a recognized term in medical terminology. It is possible that you may be referring to "formic acid" or "formate," which are terms used in chemistry and biochemistry. Formic acid is a colorless, pungent, and corrosive liquid with the chemical formula HCOOH. Its salts are called formates.

Formate is the anion (negatively charged ion) of formic acid, with the chemical formula HCOO-. Formate can be found in various biological systems and is involved in several metabolic processes. If you could provide more context or clarify your question, I would be happy to help further.

Culture media is a substance that is used to support the growth of microorganisms or cells in an artificial environment, such as a petri dish or test tube. It typically contains nutrients and other factors that are necessary for the growth and survival of the organisms being cultured. There are many different types of culture media, each with its own specific formulation and intended use. Some common examples include blood agar, which is used to culture bacteria; Sabouraud dextrose agar, which is used to culture fungi; and Eagle's minimum essential medium, which is used to culture animal cells.

'Escherichia coli (E. coli) proteins' refer to the various types of proteins that are produced and expressed by the bacterium Escherichia coli. These proteins play a critical role in the growth, development, and survival of the organism. They are involved in various cellular processes such as metabolism, DNA replication, transcription, translation, repair, and regulation.

E. coli is a gram-negative, facultative anaerobe that is commonly found in the intestines of warm-blooded organisms. It is widely used as a model organism in scientific research due to its well-studied genetics, rapid growth, and ability to be easily manipulated in the laboratory. As a result, many E. coli proteins have been identified, characterized, and studied in great detail.

Some examples of E. coli proteins include enzymes involved in carbohydrate metabolism such as lactase, sucrase, and maltose; proteins involved in DNA replication such as the polymerases, single-stranded binding proteins, and helicases; proteins involved in transcription such as RNA polymerase and sigma factors; proteins involved in translation such as ribosomal proteins, tRNAs, and aminoacyl-tRNA synthetases; and regulatory proteins such as global regulators, two-component systems, and transcription factors.

Understanding the structure, function, and regulation of E. coli proteins is essential for understanding the basic biology of this important organism, as well as for developing new strategies for combating bacterial infections and improving industrial processes involving bacteria.

Cyanides are a group of chemical compounds that contain the cyano group, -CN, which consists of a carbon atom triple-bonded to a nitrogen atom. They are highly toxic and can cause rapid death due to the inhibition of cellular respiration. Cyanide ions (CN-) bind to the ferric iron in cytochrome c oxidase, a crucial enzyme in the electron transport chain, preventing the flow of electrons and the production of ATP, leading to cellular asphyxiation.

Common sources of cyanides include industrial chemicals such as hydrogen cyanide (HCN) and potassium cyanide (KCN), as well as natural sources like certain fruits, nuts, and plants. Exposure to high levels of cyanides can occur through inhalation, ingestion, or skin absorption, leading to symptoms such as headache, dizziness, nausea, vomiting, rapid heartbeat, seizures, coma, and ultimately death. Treatment for cyanide poisoning typically involves the use of antidotes that bind to cyanide ions and convert them into less toxic forms, such as thiosulfate and rhodanese.

Fermentation is a metabolic process in which an organism converts carbohydrates into alcohol or organic acids using enzymes. In the absence of oxygen, certain bacteria, yeasts, and fungi convert sugars into carbon dioxide, hydrogen, and various end products, such as alcohol, lactic acid, or acetic acid. This process is commonly used in food production, such as in making bread, wine, and beer, as well as in industrial applications for the production of biofuels and chemicals.

I believe you may have meant to ask for the definition of "pyruvate dehydrogenase complex" rather than "pyruvate synthase," as I couldn't find any relevant medical information regarding a specific enzyme named "pyruvate synthase."

Pyruvate dehydrogenase complex (PDC) is a crucial enzyme complex in the human body, playing an essential role in cellular energy production. PDC is located within the mitochondrial matrix and catalyzes the oxidative decarboxylation of pyruvate, the end product of glycolysis, into acetyl-CoA. This process connects the glycolytic pathway to the citric acid cycle (Krebs cycle) and enables the continuation of aerobic respiration for efficient energy production in the form of ATP.

The pyruvate dehydrogenase complex consists of three main enzymes: pyruvate dehydrogenase (E1), dihydrolipoyl transacetylase (E2), and dihydrolipoyl dehydrogenase (E3). Additionally, two accessory proteins, E3-binding protein (E3BP) and protein X, are part of the complex. These enzymes work together to facilitate the conversion of pyruvate into acetyl-CoA, CO2, and NADH. Dysfunction in the pyruvate dehydrogenase complex can lead to various metabolic disorders and neurological symptoms.

A bacterial gene is a segment of DNA (or RNA in some viruses) that contains the genetic information necessary for the synthesis of a functional bacterial protein or RNA molecule. These genes are responsible for encoding various characteristics and functions of bacteria such as metabolism, reproduction, and resistance to antibiotics. They can be transmitted between bacteria through horizontal gene transfer mechanisms like conjugation, transformation, and transduction. Bacterial genes are often organized into operons, which are clusters of genes that are transcribed together as a single mRNA molecule.

It's important to note that the term "bacterial gene" is used to describe genetic elements found in bacteria, but not all genetic elements in bacteria are considered genes. For example, some DNA sequences may not encode functional products and are therefore not considered genes. Additionally, some bacterial genes may be plasmid-borne or phage-borne, rather than being located on the bacterial chromosome.

Formate dehydrogenases (FDH) are a group of enzymes that catalyze the oxidation of formic acid (formate) to carbon dioxide and hydrogen or to carbon dioxide and water, depending on the type of FDH. The reaction is as follows:

Formic acid + Coenzyme Q (or NAD+) -> Carbon dioxide + H2 (or H2O) + Reduced coenzyme Q (or NADH)

FDHs are widely distributed in nature and can be found in various organisms, including bacteria, archaea, and eukaryotes. They play a crucial role in the metabolism of many microorganisms that use formate as an electron donor for energy conservation or as a carbon source for growth. In addition to their biological significance, FDHs have attracted much interest as biocatalysts for various industrial applications, such as the production of hydrogen, reduction of CO2, and detoxification of formic acid in animal feed.

FDHs can be classified into two main types based on their cofactor specificity: NAD-dependent FDHs and quinone-dependent FDHs. NAD-dependent FDHs use nicotinamide adenine dinucleotide (NAD+) as a cofactor, while quinone-dependent FDHs use menaquinone or ubiquinone as a cofactor. Both types of FDHs have a similar reaction mechanism that involves the transfer of a hydride ion from formate to the cofactor and the release of carbon dioxide.

FDHs are composed of two subunits: a small subunit containing one or two [4Fe-4S] clusters and a large subunit containing a molybdenum cofactor (Moco) and one or two [2Fe-2S] clusters. Moco is a complex prosthetic group that consists of a pterin ring, a dithiolene group, and a molybdenum atom coordinated to three ligands: a sulfur atom from the dithiolene group, a terminal oxygen atom from a mononucleotide, and a serine residue. The molybdenum center can adopt different oxidation states (+4, +5, or +6) during the catalytic cycle, allowing for the transfer of electrons and the activation of formate.

FDHs have various applications in biotechnology and industry, such as the production of hydrogen gas, the removal of nitrate from wastewater, and the synthesis of fine chemicals. The high selectivity and efficiency of FDHs make them attractive catalysts for these processes, which require mild reaction conditions and low energy inputs. However, the stability and activity of FDHs are often limited by their sensitivity to oxygen and other inhibitors, which can affect their performance in industrial settings. Therefore, efforts have been made to improve the properties of FDHs through protein engineering, genetic modification, and immobilization techniques.

Chlamydomonas reinhardtii is a species of single-celled, freshwater green algae. It is commonly used as a model organism in scientific research due to its simple unicellular structure and the ease with which it can be genetically manipulated. C. reinhardtii has a single, large chloroplast that contains both photosynthetic pigments and a nucleomorph, a remnant of a secondary endosymbiotic event where another alga was engulfed by an ancestral eukaryote. This species is capable of both phototactic and photophobic responses, allowing it to move towards or away from light sources. Additionally, C. reinhardtii has two flagella for locomotion, making it a popular subject for ciliary and flagellar research. It undergoes closed mitosis within its single, diploid nucleus, which is surrounded by a cell wall composed of glycoproteins. The genome of C. reinhardtii has been fully sequenced, providing valuable insights into the molecular mechanisms underlying photosynthesis, flagellar assembly, and other fundamental biological processes.

Hydrogenase is not a medical term per se, but a biochemical term. It is used to describe an enzyme that catalyzes the reversible conversion between molecular hydrogen (H2) and protons (H+) or vice versa. These enzymes are found in certain bacteria, algae, and archaea, and they play a crucial role in their energy metabolism, particularly in processes like hydrogen production and consumption.

While not directly related to medical terminology, understanding the function of hydrogenase can be important in fields such as microbiology, molecular biology, and environmental science, which can have implications for human health in areas like infectious diseases, biofuels, and waste management.

An operon is a genetic unit in prokaryotic organisms (like bacteria) consisting of a cluster of genes that are transcribed together as a single mRNA molecule, which then undergoes translation to produce multiple proteins. This genetic organization allows for the coordinated regulation of genes that are involved in the same metabolic pathway or functional process. The unit typically includes promoter and operator regions that control the transcription of the operon, as well as structural genes encoding the proteins. Operons were first discovered in bacteria, but similar genetic organizations have been found in some eukaryotic organisms, such as yeast.

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

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

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

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

The lac operon is a genetic regulatory system found in the bacteria Escherichia coli that controls the expression of genes responsible for the metabolism of lactose as a source of energy. It consists of three structural genes (lacZ, lacY, and lacA) that code for enzymes involved in lactose metabolism, as well as two regulatory elements: the lac promoter and the lac operator.

The lac repressor protein, produced by the lacI gene, binds to the lac operator sequence when lactose is not present, preventing RNA polymerase from transcribing the structural genes. When lactose is available, it is converted into allolactose, which acts as an inducer and binds to the lac repressor protein, causing a conformational change that prevents it from binding to the operator sequence. This allows RNA polymerase to bind to the promoter and transcribe the structural genes, leading to the production of enzymes necessary for lactose metabolism.

In summary, the lac operon is a genetic regulatory system in E. coli that controls the expression of genes involved in lactose metabolism based on the availability of lactose as a substrate.

2,4-Dinitrophenol (DNP) is a chemical compound with the formula C6H4N2O5. It is an organic compound that contains two nitro groups (-NO2) attached to a phenol molecule. DNP is a yellow, crystalline solid that is slightly soluble in water and more soluble in organic solvents.

In the medical field, DNP has been used in the past as a weight loss agent due to its ability to disrupt mitochondrial function and increase metabolic rate. However, its use as a weight loss drug was banned in the United States in the 1930s due to serious side effects, including cataracts, skin lesions, and hyperthermia, which can lead to death.

Exposure to DNP can occur through ingestion, inhalation, or skin contact. Acute exposure to high levels of DNP can cause symptoms such as nausea, vomiting, sweating, dizziness, headache, and rapid heartbeat. Chronic exposure to lower levels of DNP can lead to cataracts, skin lesions, and damage to the nervous system, liver, and kidneys.

It is important to note that DNP is not approved for use as a weight loss agent or any other medical purpose in the United States. Its use as a dietary supplement or weight loss aid is illegal and can be dangerous.

Beta-galactosidase is an enzyme that catalyzes the hydrolysis of beta-galactosides into monosaccharides. It is found in various organisms, including bacteria, yeast, and mammals. In humans, it plays a role in the breakdown and absorption of certain complex carbohydrates, such as lactose, in the small intestine. Deficiency of this enzyme in humans can lead to a disorder called lactose intolerance. In scientific research, beta-galactosidase is often used as a marker for gene expression and protein localization studies.

Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.

The Electron Transport Chain (ETC) is a series of complexes in the inner mitochondrial membrane that are involved in the process of cellular respiration. It is the final pathway for electrons derived from the oxidation of nutrients such as glucose, fatty acids, and amino acids to be transferred to molecular oxygen. This transfer of electrons drives the generation of a proton gradient across the inner mitochondrial membrane, which is then used by ATP synthase to produce ATP, the main energy currency of the cell.

The electron transport chain consists of four complexes (I-IV) and two mobile electron carriers (ubiquinone and cytochrome c). Electrons from NADH and FADH2 are transferred to Complex I and Complex II respectively, which then pass them along to ubiquinone. Ubiquinone then transfers the electrons to Complex III, which passes them on to cytochrome c. Finally, cytochrome c transfers the electrons to Complex IV, where they combine with oxygen and protons to form water.

The transfer of electrons through the ETC is accompanied by the pumping of protons from the mitochondrial matrix to the intermembrane space, creating a proton gradient. The flow of protons back across the inner membrane through ATP synthase drives the synthesis of ATP from ADP and inorganic phosphate.

Overall, the electron transport chain is a crucial process for generating energy in the form of ATP in the cell, and it plays a key role in many metabolic pathways.

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

NAD (Nicotinamide Adenine Dinucleotide) is a coenzyme found in all living cells. It plays an essential role in cellular metabolism, particularly in redox reactions, where it acts as an electron carrier. NAD exists in two forms: NAD+, which accepts electrons and becomes reduced to NADH. This pairing of NAD+/NADH is involved in many fundamental biological processes such as generating energy in the form of ATP during cellular respiration, and serving as a critical cofactor for various enzymes that regulate cellular functions like DNA repair, gene expression, and cell death.

Maintaining optimal levels of NAD+/NADH is crucial for overall health and longevity, as it declines with age and in certain disease states. Therefore, strategies to boost NAD+ levels are being actively researched for their potential therapeutic benefits in various conditions such as aging, neurodegenerative disorders, and metabolic diseases.

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

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

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

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

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

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

"Salmonella enterica" serovar "Typhimurium" is a subspecies of the bacterial species Salmonella enterica, which is a gram-negative, facultatively anaerobic, rod-shaped bacterium. It is a common cause of foodborne illness in humans and animals worldwide. The bacteria can be found in a variety of sources, including contaminated food and water, raw meat, poultry, eggs, and dairy products.

The infection caused by Salmonella Typhimurium is typically self-limiting and results in gastroenteritis, which is characterized by symptoms such as diarrhea, abdominal cramps, fever, and vomiting. However, in some cases, the infection can spread to other parts of the body and cause more severe illness, particularly in young children, older adults, and people with weakened immune systems.

Salmonella Typhimurium is a major public health concern due to its ability to cause outbreaks of foodborne illness, as well as its potential to develop antibiotic resistance. Proper food handling, preparation, and storage practices can help prevent the spread of Salmonella Typhimurium and other foodborne pathogens.

Antimycin A is an antibiotic substance produced by various species of Streptomyces bacteria. It is known to inhibit the electron transport chain in mitochondria, which can lead to cellular dysfunction and death. Antimycin A has been used in research to study the mechanisms of cellular respiration and oxidative phosphorylation.

In a medical context, antimycin A is not used as a therapeutic agent due to its toxicity to mammalian cells. However, it may be used in laboratory settings to investigate various biological processes or to develop new therapies for diseases related to mitochondrial dysfunction.

'Bacillus cereus' is a gram-positive, rod-shaped bacterium that is commonly found in soil and food. It can produce heat-resistant spores, which allow it to survive in a wide range of temperatures and environments. This bacterium can cause two types of foodborne illnesses: a diarrheal type and an emetic (vomiting) type.

The diarrheal type of illness is caused by the consumption of foods contaminated with large numbers of vegetative cells of B. cereus. The symptoms typically appear within 6 to 15 hours after ingestion and include watery diarrhea, abdominal cramps, and nausea. Vomiting may also occur in some cases.

The emetic type of illness is caused by the consumption of foods contaminated with B. cereus toxins. This type of illness is characterized by nausea and vomiting that usually occur within 0.5 to 6 hours after ingestion. The most common sources of B. cereus contamination include rice, pasta, and other starchy foods that have been cooked and left at room temperature for several hours.

Proper food handling, storage, and cooking practices can help prevent B. cereus infections. It is important to refrigerate or freeze cooked foods promptly, reheat them thoroughly, and avoid leaving them at room temperature for extended periods.

Metabolism is the complex network of chemical reactions that occur within our bodies to maintain life. It involves two main types of processes: catabolism, which is the breaking down of molecules to release energy, and anabolism, which is the building up of molecules using energy. These reactions are necessary for the body to grow, reproduce, respond to environmental changes, and repair itself. Metabolism is a continuous process that occurs at the cellular level and is regulated by enzymes, hormones, and other signaling molecules. It is influenced by various factors such as age, genetics, diet, physical activity, and overall health status.

I'm sorry for any confusion, but "Hydrogen" is not a medical term. It is a chemical element with the symbol H and atomic number 1. It is the lightest and most abundant chemical element in the universe, making up about 75% of its elemental mass.

In a medical context, hydrogen can be discussed in terms of molecular hydrogen (H2) which has been studied for potential therapeutic benefits. Some research explores its use as an antioxidant and anti-inflammatory agent, but more studies are needed to confirm these effects and understand the mechanisms behind them.

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

Carbonyl cyanide m-chlorophenyl hydrazone (CCCP) is a chemical compound that is often used in research and scientific studies. It is an ionophore, which is a type of molecule that can transport ions across biological membranes. CCCP specifically transports protons (H+ ions) across membranes.

In biochemistry and cell biology, CCCP is commonly used as an uncoupler of oxidative phosphorylation. This is a process by which cells generate energy in the form of ATP (adenosine triphosphate) using the energy from the electron transport chain. By disrupting the proton gradient across the inner mitochondrial membrane, CCCP prevents the synthesis of ATP and causes a rapid depletion of cellular energy stores.

The medical relevance of CCCP is primarily limited to its use as a research tool in laboratory studies. It is not used as a therapeutic agent in clinical medicine.

Regulator genes are a type of gene that regulates the activity of other genes in an organism. They do not code for a specific protein product but instead control the expression of other genes by producing regulatory proteins such as transcription factors, repressors, or enhancers. These regulatory proteins bind to specific DNA sequences near the target genes and either promote or inhibit their transcription into mRNA. This allows regulator genes to play a crucial role in coordinating complex biological processes, including development, differentiation, metabolism, and response to environmental stimuli.

There are several types of regulator genes, including:

1. Constitutive regulators: These genes are always active and produce regulatory proteins that control the expression of other genes in a consistent manner.
2. Inducible regulators: These genes respond to specific signals or environmental stimuli by producing regulatory proteins that modulate the expression of target genes.
3. Negative regulators: These genes produce repressor proteins that bind to DNA and inhibit the transcription of target genes, thereby reducing their expression.
4. Positive regulators: These genes produce activator proteins that bind to DNA and promote the transcription of target genes, thereby increasing their expression.
5. Master regulators: These genes control the expression of multiple downstream target genes involved in specific biological processes or developmental pathways.

Regulator genes are essential for maintaining proper gene expression patterns and ensuring normal cellular function. Mutations in regulator genes can lead to various diseases, including cancer, developmental disorders, and metabolic dysfunctions.

I'm sorry for any confusion, but "Molybdenum" is not a medical term. It is an element with the symbol Mo and atomic number 42 on the periodic table. Molybdenum is used in various industries, including medicine, for example in the production of surgical instruments and some prosthetics due to its strength and resistance to corrosion. However, it is not a term used to describe a medical condition or bodily process. If you have any questions related to elements and their uses in medicine, I'd be happy to help with those!

Succinate dehydrogenase (SDH) is an enzyme complex that plays a crucial role in the process of cellular respiration, specifically in the citric acid cycle (also known as the Krebs cycle) and the electron transport chain. It is located in the inner mitochondrial membrane of eukaryotic cells.

SDH catalyzes the oxidation of succinate to fumarate, converting it into a molecule of fadaquate in the process. During this reaction, two electrons are transferred from succinate to the FAD cofactor within the SDH enzyme complex, reducing it to FADH2. These electrons are then passed on to ubiquinone (CoQ), which is a mobile electron carrier in the electron transport chain, leading to the generation of ATP, the main energy currency of the cell.

SDH is also known as mitochondrial complex II because it is the second complex in the electron transport chain. Mutations in the genes encoding SDH subunits or associated proteins have been linked to various human diseases, including hereditary paragangliomas, pheochromocytomas, gastrointestinal stromal tumors (GISTs), and some forms of neurodegenerative disorders.

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

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

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

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

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

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

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

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

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

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

A bioreactor is a device or system that supports and controls the conditions necessary for biological organisms, cells, or tissues to grow and perform their specific functions. It provides a controlled environment with appropriate temperature, pH, nutrients, and other factors required for the desired biological process to occur. Bioreactors are widely used in various fields such as biotechnology, pharmaceuticals, agriculture, and environmental science for applications like production of therapeutic proteins, vaccines, biofuels, enzymes, and wastewater treatment.

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

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

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

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

Photosynthesis is not strictly a medical term, but it is a fundamental biological process with significant implications for medicine, particularly in understanding energy production in cells and the role of oxygen in sustaining life. Here's a general biological definition:

Photosynthesis is a process by which plants, algae, and some bacteria convert light energy, usually from the sun, into chemical energy in the form of organic compounds, such as glucose (or sugar), using water and carbon dioxide. This process primarily takes place in the chloroplasts of plant cells, specifically in structures called thylakoids. The overall reaction can be summarized as:

6 CO2 + 6 H2O + light energy → C6H12O6 + 6 O2

In this equation, carbon dioxide (CO2) and water (H2O) are the reactants, while glucose (C6H12O6) and oxygen (O2) are the products. Photosynthesis has two main stages: the light-dependent reactions and the light-independent reactions (Calvin cycle). The light-dependent reactions occur in the thylakoid membrane and involve the conversion of light energy into ATP and NADPH, which are used to power the Calvin cycle. The Calvin cycle takes place in the stroma of chloroplasts and involves the synthesis of glucose from CO2 and water using the ATP and NADPH generated during the light-dependent reactions.

Understanding photosynthesis is crucial for understanding various biological processes, including cellular respiration, plant metabolism, and the global carbon cycle. Additionally, research into artificial photosynthesis has potential applications in renewable energy production and environmental remediation.

Promoter regions in genetics refer to specific DNA sequences located near the transcription start site of a gene. They serve as binding sites for RNA polymerase and various transcription factors that regulate the initiation of gene transcription. These regulatory elements help control the rate of transcription and, therefore, the level of gene expression. Promoter regions can be composed of different types of sequences, such as the TATA box and CAAT box, and their organization and composition can vary between different genes and species.

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

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

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

Gene expression regulation in fungi refers to the complex cellular processes that control the production of proteins and other functional gene products in response to various internal and external stimuli. This regulation is crucial for normal growth, development, and adaptation of fungal cells to changing environmental conditions.

In fungi, gene expression is regulated at multiple levels, including transcriptional, post-transcriptional, translational, and post-translational modifications. Key regulatory mechanisms include:

1. Transcription factors (TFs): These proteins bind to specific DNA sequences in the promoter regions of target genes and either activate or repress their transcription. Fungi have a diverse array of TFs that respond to various signals, such as nutrient availability, stress, developmental cues, and quorum sensing.
2. Chromatin remodeling: The organization and compaction of DNA into chromatin can influence gene expression. Fungi utilize ATP-dependent chromatin remodeling complexes and histone modifying enzymes to alter chromatin structure, thereby facilitating or inhibiting the access of transcriptional machinery to genes.
3. Non-coding RNAs: Small non-coding RNAs (sncRNAs) play a role in post-transcriptional regulation of gene expression in fungi. These sncRNAs can guide RNA-induced transcriptional silencing (RITS) complexes to specific target loci, leading to the repression of gene expression through histone modifications and DNA methylation.
4. Alternative splicing: Fungi employ alternative splicing mechanisms to generate multiple mRNA isoforms from a single gene, thereby increasing proteome diversity. This process can be regulated by RNA-binding proteins that recognize specific sequence motifs in pre-mRNAs and promote or inhibit splicing events.
5. Protein stability and activity: Post-translational modifications (PTMs) of proteins, such as phosphorylation, ubiquitination, and sumoylation, can influence their stability, localization, and activity. These PTMs play a crucial role in regulating various cellular processes, including signal transduction, stress response, and cell cycle progression.

Understanding the complex interplay between these regulatory mechanisms is essential for elucidating the molecular basis of fungal development, pathogenesis, and drug resistance. This knowledge can be harnessed to develop novel strategies for combating fungal infections and improving agricultural productivity.

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

Bacterial DNA refers to the genetic material found in bacteria. It is composed of a double-stranded helix containing four nucleotide bases - adenine (A), thymine (T), guanine (G), and cytosine (C) - that are linked together by phosphodiester bonds. The sequence of these bases in the DNA molecule carries the genetic information necessary for the growth, development, and reproduction of bacteria.

Bacterial DNA is circular in most bacterial species, although some have linear chromosomes. In addition to the main chromosome, many bacteria also contain small circular pieces of DNA called plasmids that can carry additional genes and provide resistance to antibiotics or other environmental stressors.

Unlike eukaryotic cells, which have their DNA enclosed within a nucleus, bacterial DNA is present in the cytoplasm of the cell, where it is in direct contact with the cell's metabolic machinery. This allows for rapid gene expression and regulation in response to changing environmental conditions.

Physiological adaptation refers to the changes or modifications that occur in an organism's biological functions or structures as a result of environmental pressures or changes. These adaptations enable the organism to survive and reproduce more successfully in its environment. They can be short-term, such as the constriction of blood vessels in response to cold temperatures, or long-term, such as the evolution of longer limbs in animals that live in open environments.

In the context of human physiology, examples of physiological adaptation include:

1. Acclimatization: The process by which the body adjusts to changes in environmental conditions, such as altitude or temperature. For example, when a person moves to a high-altitude location, their body may produce more red blood cells to compensate for the lower oxygen levels, leading to improved oxygen delivery to tissues.

2. Exercise adaptation: Regular physical activity can lead to various physiological adaptations, such as increased muscle strength and endurance, enhanced cardiovascular function, and improved insulin sensitivity.

3. Hormonal adaptation: The body can adjust hormone levels in response to changes in the environment or internal conditions. For instance, during prolonged fasting, the body releases stress hormones like cortisol and adrenaline to help maintain energy levels and prevent muscle wasting.

4. Sensory adaptation: Our senses can adapt to different stimuli over time. For example, when we enter a dark room after being in bright sunlight, it takes some time for our eyes to adjust to the new light level. This process is known as dark adaptation.

5. Aging-related adaptations: As we age, various physiological changes occur that help us adapt to the changing environment and maintain homeostasis. These include changes in body composition, immune function, and cognitive abilities.

Lactates, also known as lactic acid, are compounds that are produced by muscles during intense exercise or other conditions of low oxygen supply. They are formed from the breakdown of glucose in the absence of adequate oxygen to complete the full process of cellular respiration. This results in the production of lactate and a hydrogen ion, which can lead to a decrease in pH and muscle fatigue.

In a medical context, lactates may be measured in the blood as an indicator of tissue oxygenation and metabolic status. Elevated levels of lactate in the blood, known as lactic acidosis, can indicate poor tissue perfusion or hypoxia, and may be seen in conditions such as sepsis, cardiac arrest, and severe shock. It is important to note that lactates are not the primary cause of acidemia (low pH) in lactic acidosis, but rather a marker of the underlying process.

Biomass is defined in the medical field as a renewable energy source derived from organic materials, primarily plant matter, that can be burned or converted into fuel. This includes materials such as wood, agricultural waste, and even methane gas produced by landfills. Biomass is often used as a source of heat, electricity, or transportation fuels, and its use can help reduce greenhouse gas emissions and dependence on fossil fuels.

In the context of human health, biomass burning can have both positive and negative impacts. On one hand, biomass can provide a source of heat and energy for cooking and heating, which can improve living standards and reduce exposure to harmful pollutants from traditional cooking methods such as open fires. On the other hand, biomass burning can also produce air pollution, including particulate matter and toxic chemicals, that can have negative effects on respiratory health and contribute to climate change.

Therefore, while biomass has the potential to be a sustainable and low-carbon source of energy, it is important to consider the potential health and environmental impacts of its use and implement appropriate measures to minimize any negative effects.

Glycolysis is a fundamental metabolic pathway that occurs in the cytoplasm of cells, consisting of a series of biochemical reactions. It's the process by which a six-carbon glucose molecule is broken down into two three-carbon pyruvate molecules. This process generates a net gain of two ATP molecules (the main energy currency in cells), two NADH molecules, and two water molecules.

Glycolysis can be divided into two stages: the preparatory phase (or 'energy investment' phase) and the payoff phase (or 'energy generation' phase). During the preparatory phase, glucose is phosphorylated twice to form glucose-6-phosphate and then converted to fructose-1,6-bisphosphate. These reactions consume two ATP molecules but set up the subsequent breakdown of fructose-1,6-bisphosphate into triose phosphates in the payoff phase. In this second stage, each triose phosphate is further oxidized and degraded to produce one pyruvate molecule, one NADH molecule, and one ATP molecule through substrate-level phosphorylation.

Glycolysis does not require oxygen to proceed; thus, it can occur under both aerobic (with oxygen) and anaerobic (without oxygen) conditions. In the absence of oxygen, the pyruvate produced during glycolysis is further metabolized through fermentation pathways such as lactic acid fermentation or alcohol fermentation to regenerate NAD+, which is necessary for glycolysis to continue.

In summary, glycolysis is a crucial process in cellular energy metabolism, allowing cells to convert glucose into ATP and other essential molecules while also serving as a starting point for various other biochemical pathways.

"Cold temperature" is a relative term and its definition can vary depending on the context. In general, it refers to temperatures that are lower than those normally experienced or preferred by humans and other warm-blooded animals. In a medical context, cold temperature is often defined as an environmental temperature that is below 16°C (60.8°F).

Exposure to cold temperatures can have various physiological effects on the human body, such as vasoconstriction of blood vessels near the skin surface, increased heart rate and metabolic rate, and shivering, which helps to generate heat and maintain body temperature. Prolonged exposure to extreme cold temperatures can lead to hypothermia, a potentially life-threatening condition characterized by a drop in core body temperature below 35°C (95°F).

It's worth noting that some people may have different sensitivities to cold temperatures due to factors such as age, health status, and certain medical conditions. For example, older adults, young children, and individuals with circulatory or neurological disorders may be more susceptible to the effects of cold temperatures.

Acetyltransferases are a type of enzyme that facilitates the transfer of an acetyl group (a chemical group consisting of an acetyl molecule, which is made up of carbon, hydrogen, and oxygen atoms) from a donor molecule to a recipient molecule. This transfer of an acetyl group can modify the function or activity of the recipient molecule.

In the context of biology and medicine, acetyltransferases are important for various cellular processes, including gene expression, DNA replication, and protein function. For example, histone acetyltransferases (HATs) are a type of acetyltransferase that add an acetyl group to the histone proteins around which DNA is wound. This modification can alter the structure of the chromatin, making certain genes more or less accessible for transcription, and thereby influencing gene expression.

Abnormal regulation of acetyltransferases has been implicated in various diseases, including cancer, neurodegenerative disorders, and infectious diseases. Therefore, understanding the function and regulation of these enzymes is an important area of research in biomedicine.

Ethanol is the medical term for pure alcohol, which is a colorless, clear, volatile, flammable liquid with a characteristic odor and burning taste. It is the type of alcohol that is found in alcoholic beverages and is produced by the fermentation of sugars by yeasts.

In the medical field, ethanol is used as an antiseptic and disinfectant, and it is also used as a solvent for various medicinal preparations. It has central nervous system depressant properties and is sometimes used as a sedative or to induce sleep. However, excessive consumption of ethanol can lead to alcohol intoxication, which can cause a range of negative health effects, including impaired judgment, coordination, and memory, as well as an increased risk of accidents, injuries, and chronic diseases such as liver disease and addiction.

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

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

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

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

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

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

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

Bacteriological techniques refer to the various methods and procedures used in the laboratory for the cultivation, identification, and study of bacteria. These techniques are essential in fields such as medicine, biotechnology, and research. Here are some common bacteriological techniques:

1. **Sterilization**: This is a process that eliminates or kills all forms of life, including bacteria, viruses, fungi, and spores. Common sterilization methods include autoclaving (using steam under pressure), dry heat (in an oven), chemical sterilants, and radiation.

2. **Aseptic Technique**: This refers to practices used to prevent contamination of sterile materials or environments with microorganisms. It includes the use of sterile equipment, gloves, and lab coats, as well as techniques such as flaming, alcohol swabbing, and using aseptic transfer devices.

3. **Media Preparation**: This involves the preparation of nutrient-rich substances that support bacterial growth. There are various types of media, including solid (agar), liquid (broth), and semi-solid (e.g., stab agar). The choice of medium depends on the type of bacteria being cultured and the purpose of the investigation.

4. **Inoculation**: This is the process of introducing a bacterial culture into a medium. It can be done using a loop, swab, or needle. The inoculum should be taken from a pure culture to avoid contamination.

5. **Incubation**: After inoculation, the bacteria are allowed to grow under controlled conditions of temperature, humidity, and atmospheric composition. This process is called incubation.

6. **Staining and Microscopy**: Bacteria are too small to be seen with the naked eye. Therefore, they need to be stained and observed under a microscope. Gram staining is a common method used to differentiate between two major groups of bacteria based on their cell wall composition.

7. **Biochemical Tests**: These are tests used to identify specific bacterial species based on their biochemical characteristics, such as their ability to ferment certain sugars, produce particular enzymes, or resist certain antibiotics.

8. **Molecular Techniques**: Advanced techniques like PCR and DNA sequencing can provide more precise identification of bacteria. They can also be used for genetic analysis and epidemiological studies.

Remember, handling microorganisms requires careful attention to biosafety procedures to prevent accidental infection or environmental contamination.

Carbon dioxide (CO2) is a colorless, odorless gas that is naturally present in the Earth's atmosphere. It is a normal byproduct of cellular respiration in humans, animals, and plants, and is also produced through the combustion of fossil fuels such as coal, oil, and natural gas.

In medical terms, carbon dioxide is often used as a respiratory stimulant and to maintain the pH balance of blood. It is also used during certain medical procedures, such as laparoscopic surgery, to insufflate (inflate) the abdominal cavity and create a working space for the surgeon.

Elevated levels of carbon dioxide in the body can lead to respiratory acidosis, a condition characterized by an increased concentration of carbon dioxide in the blood and a decrease in pH. This can occur in conditions such as chronic obstructive pulmonary disease (COPD), asthma, or other lung diseases that impair breathing and gas exchange. Symptoms of respiratory acidosis may include shortness of breath, confusion, headache, and in severe cases, coma or death.

Gene deletion is a type of mutation where a segment of DNA, containing one or more genes, is permanently lost or removed from a chromosome. This can occur due to various genetic mechanisms such as homologous recombination, non-homologous end joining, or other types of genomic rearrangements.

The deletion of a gene can have varying effects on the organism, depending on the function of the deleted gene and its importance for normal physiological processes. If the deleted gene is essential for survival, the deletion may result in embryonic lethality or developmental abnormalities. However, if the gene is non-essential or has redundant functions, the deletion may not have any noticeable effects on the organism's phenotype.

Gene deletions can also be used as a tool in genetic research to study the function of specific genes and their role in various biological processes. For example, researchers may use gene deletion techniques to create genetically modified animal models to investigate the impact of gene deletion on disease progression or development.

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

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

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

Biological transport, active is the process by which cells use energy to move materials across their membranes from an area of lower concentration to an area of higher concentration. This type of transport is facilitated by specialized proteins called transporters or pumps that are located in the cell membrane. These proteins undergo conformational changes to physically carry the molecules through the lipid bilayer of the membrane, often against their concentration gradient.

Active transport requires energy because it works against the natural tendency of molecules to move from an area of higher concentration to an area of lower concentration, a process known as diffusion. Cells obtain this energy in the form of ATP (adenosine triphosphate), which is produced through cellular respiration.

Examples of active transport include the uptake of glucose and amino acids into cells, as well as the secretion of hormones and neurotransmitters. The sodium-potassium pump, which helps maintain resting membrane potential in nerve and muscle cells, is a classic example of an active transporter.

Spectrophotometry is a technical analytical method used in the field of medicine and science to measure the amount of light absorbed or transmitted by a substance at specific wavelengths. This technique involves the use of a spectrophotometer, an instrument that measures the intensity of light as it passes through a sample.

In medical applications, spectrophotometry is often used in laboratory settings to analyze various biological samples such as blood, urine, and tissues. For example, it can be used to measure the concentration of specific chemicals or compounds in a sample by measuring the amount of light that is absorbed or transmitted at specific wavelengths.

In addition, spectrophotometry can also be used to assess the properties of biological tissues, such as their optical density and thickness. This information can be useful in the diagnosis and treatment of various medical conditions, including skin disorders, eye diseases, and cancer.

Overall, spectrophotometry is a valuable tool for medical professionals and researchers seeking to understand the composition and properties of various biological samples and tissues.

"Pseudomonas aeruginosa" is a medically important, gram-negative, rod-shaped bacterium that is widely found in the environment, such as in soil, water, and on plants. It's an opportunistic pathogen, meaning it usually doesn't cause infection in healthy individuals but can cause severe and sometimes life-threatening infections in people with weakened immune systems, burns, or chronic lung diseases like cystic fibrosis.

P. aeruginosa is known for its remarkable ability to resist many antibiotics and disinfectants due to its intrinsic resistance mechanisms and the acquisition of additional resistance determinants. It can cause various types of infections, including respiratory tract infections, urinary tract infections, gastrointestinal infections, dermatitis, and severe bloodstream infections known as sepsis.

The bacterium produces a variety of virulence factors that contribute to its pathogenicity, such as exotoxins, proteases, and pigments like pyocyanin and pyoverdine, which aid in iron acquisition and help the organism evade host immune responses. Effective infection control measures, appropriate use of antibiotics, and close monitoring of high-risk patients are crucial for managing P. aeruginosa infections.

Transcription factors are proteins that play a crucial role in regulating gene expression by controlling the transcription of DNA to messenger RNA (mRNA). They function by binding to specific DNA sequences, known as response elements, located in the promoter region or enhancer regions of target genes. This binding can either activate or repress the initiation of transcription, depending on the properties and interactions of the particular transcription factor. Transcription factors often act as part of a complex network of regulatory proteins that determine the precise spatiotemporal patterns of gene expression during development, differentiation, and homeostasis in an organism.

Spectrophotometry, Infrared is a scientific analytical technique used to measure the absorption or transmission of infrared light by a sample. It involves the use of an infrared spectrophotometer, which directs infrared radiation through a sample and measures the intensity of the radiation that is transmitted or absorbed by the sample at different wavelengths within the infrared region of the electromagnetic spectrum.

Infrared spectroscopy can be used to identify and quantify functional groups and chemical bonds present in a sample, as well as to study the molecular structure and composition of materials. The resulting infrared spectrum provides a unique "fingerprint" of the sample, which can be compared with reference spectra to aid in identification and characterization.

Infrared spectrophotometry is widely used in various fields such as chemistry, biology, pharmaceuticals, forensics, and materials science for qualitative and quantitative analysis of samples.

In the context of medical terminology, "light" doesn't have a specific or standardized definition on its own. However, it can be used in various medical terms and phrases. For example, it could refer to:

1. Visible light: The range of electromagnetic radiation that can be detected by the human eye, typically between wavelengths of 400-700 nanometers. This is relevant in fields such as ophthalmology and optometry.
2. Therapeutic use of light: In some therapies, light is used to treat certain conditions. An example is phototherapy, which uses various wavelengths of ultraviolet (UV) or visible light for conditions like newborn jaundice, skin disorders, or seasonal affective disorder.
3. Light anesthesia: A state of reduced consciousness in which the patient remains responsive to verbal commands and physical stimulation. This is different from general anesthesia where the patient is completely unconscious.
4. Pain relief using light: Certain devices like transcutaneous electrical nerve stimulation (TENS) units have a 'light' setting, indicating lower intensity or frequency of electrical impulses used for pain management.

Without more context, it's hard to provide a precise medical definition of 'light'.

Phosphates, in a medical context, refer to the salts or esters of phosphoric acid. Phosphates play crucial roles in various biological processes within the human body. They are essential components of bones and teeth, where they combine with calcium to form hydroxyapatite crystals. Phosphates also participate in energy transfer reactions as phosphate groups attached to adenosine diphosphate (ADP) and adenosine triphosphate (ATP). Additionally, they contribute to buffer systems that help maintain normal pH levels in the body.

Abnormal levels of phosphates in the blood can indicate certain medical conditions. High phosphate levels (hyperphosphatemia) may be associated with kidney dysfunction, hyperparathyroidism, or excessive intake of phosphate-containing products. Low phosphate levels (hypophosphatemia) might result from malnutrition, vitamin D deficiency, or certain diseases affecting the small intestine or kidneys. Both hypophosphatemia and hyperphosphatemia can have significant impacts on various organ systems and may require medical intervention.

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

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

Recombinant fusion proteins are artificially created biomolecules that combine the functional domains or properties of two or more different proteins into a single protein entity. They are generated through recombinant DNA technology, where the genes encoding the desired protein domains are linked together and expressed as a single, chimeric gene in a host organism, such as bacteria, yeast, or mammalian cells.

The resulting fusion protein retains the functional properties of its individual constituent proteins, allowing for novel applications in research, diagnostics, and therapeutics. For instance, recombinant fusion proteins can be designed to enhance protein stability, solubility, or immunogenicity, making them valuable tools for studying protein-protein interactions, developing targeted therapies, or generating vaccines against infectious diseases or cancer.

Examples of recombinant fusion proteins include:

1. Etaglunatide (ABT-523): A soluble Fc fusion protein that combines the heavy chain fragment crystallizable region (Fc) of an immunoglobulin with the extracellular domain of the human interleukin-6 receptor (IL-6R). This fusion protein functions as a decoy receptor, neutralizing IL-6 and its downstream signaling pathways in rheumatoid arthritis.
2. Etanercept (Enbrel): A soluble TNF receptor p75 Fc fusion protein that binds to tumor necrosis factor-alpha (TNF-α) and inhibits its proinflammatory activity, making it a valuable therapeutic option for treating autoimmune diseases like rheumatoid arthritis, ankylosing spondylitis, and psoriasis.
3. Abatacept (Orencia): A fusion protein consisting of the extracellular domain of cytotoxic T-lymphocyte antigen 4 (CTLA-4) linked to the Fc region of an immunoglobulin, which downregulates T-cell activation and proliferation in autoimmune diseases like rheumatoid arthritis.
4. Belimumab (Benlysta): A monoclonal antibody that targets B-lymphocyte stimulator (BLyS) protein, preventing its interaction with the B-cell surface receptor and inhibiting B-cell activation in systemic lupus erythematosus (SLE).
5. Romiplostim (Nplate): A fusion protein consisting of a thrombopoietin receptor agonist peptide linked to an immunoglobulin Fc region, which stimulates platelet production in patients with chronic immune thrombocytopenia (ITP).
6. Darbepoetin alfa (Aranesp): A hyperglycosylated erythropoiesis-stimulating protein that functions as a longer-acting form of recombinant human erythropoietin, used to treat anemia in patients with chronic kidney disease or cancer.
7. Palivizumab (Synagis): A monoclonal antibody directed against the F protein of respiratory syncytial virus (RSV), which prevents RSV infection and is administered prophylactically to high-risk infants during the RSV season.
8. Ranibizumab (Lucentis): A recombinant humanized monoclonal antibody fragment that binds and inhibits vascular endothelial growth factor A (VEGF-A), used in the treatment of age-related macular degeneration, diabetic retinopathy, and other ocular disorders.
9. Cetuximab (Erbitux): A chimeric monoclonal antibody that binds to epidermal growth factor receptor (EGFR), used in the treatment of colorectal cancer and head and neck squamous cell carcinoma.
10. Adalimumab (Humira): A fully humanized monoclonal antibody that targets tumor necrosis factor-alpha (TNF-α), used in the treatment of various inflammatory diseases, including rheumatoid arthritis, psoriasis, and Crohn's disease.
11. Bevacizumab (Avastin): A recombinant humanized monoclonal antibody that binds to VEGF-A, used in the treatment of various cancers, including colorectal, lung, breast, and kidney cancer.
12. Trastuzumab (Herceptin): A humanized monoclonal antibody that targets HER2/neu receptor, used in the treatment of breast cancer.
13. Rituximab (Rituxan): A chimeric monoclonal antibody that binds to CD20 antigen on B cells, used in the treatment of non-Hodgkin's lymphoma and rheumatoid arthritis.
14. Palivizumab (Synagis): A humanized monoclonal antibody that binds to the F protein of respiratory syncytial virus, used in the prevention of respiratory syncytial virus infection in high-risk infants.
15. Infliximab (Remicade): A chimeric monoclonal antibody that targets TNF-α, used in the treatment of various inflammatory diseases, including Crohn's disease, ulcerative colitis, rheumatoid arthritis, and ankylosing spondylitis.
16. Natalizumab (Tysabri): A humanized monoclonal antibody that binds to α4β1 integrin, used in the treatment of multiple sclerosis and Crohn's disease.
17. Adalimumab (Humira): A fully human monoclonal antibody that targets TNF-α, used in the treatment of various inflammatory diseases, including rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, Crohn's disease, and ulcerative colitis.
18. Golimumab (Simponi): A fully human monoclonal antibody that targets TNF-α, used in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and ulcerative colitis.
19. Certolizumab pegol (Cimzia): A PEGylated Fab' fragment of a humanized monoclonal antibody that targets TNF-α, used in the treatment of rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, and Crohn's disease.
20. Ustekinumab (Stelara): A fully human monoclonal antibody that targets IL-12 and IL-23, used in the treatment of psoriasis, psoriatic arthritis, and Crohn's disease.
21. Secukinumab (Cosentyx): A fully human monoclonal antibody that targets IL-17A, used in the treatment of psoriasis, psoriatic arthritis, and ankylosing spondylitis.
22. Ixekizumab (Taltz): A fully human monoclonal antibody that targets IL-17A, used in the treatment of psoriasis and psoriatic arthritis.
23. Brodalumab (Siliq): A fully human monoclonal antibody that targets IL-17 receptor A, used in the treatment of psoriasis.
24. Sarilumab (Kevzara): A fully human monoclonal antibody that targets the IL-6 receptor, used in the treatment of rheumatoid arthritis.
25. Tocilizumab (Actemra): A humanized monoclonal antibody that targets the IL-6 receptor, used in the treatment of rheumatoid arthritis, systemic juvenile idiopathic arthritis, polyarticular juvenile idiopathic arthritis, giant cell arteritis, and chimeric antigen receptor T-cell-induced cytokine release syndrome.
26. Siltuximab (Sylvant): A chimeric monoclonal antibody that targets IL-6, used in the treatment of multicentric Castleman disease.
27. Satralizumab (Enspryng): A humanized monoclonal antibody that targets IL-6 receptor alpha, used in the treatment of neuromyelitis optica spectrum disorder.
28. Sirukumab (Plivensia): A human monoclonal antibody that targets IL-6, used in the treatment

Restriction mapping is a technique used in molecular biology to identify the location and arrangement of specific restriction endonuclease recognition sites within a DNA molecule. Restriction endonucleases are enzymes that cut double-stranded DNA at specific sequences, producing fragments of various lengths. By digesting the DNA with different combinations of these enzymes and analyzing the resulting fragment sizes through techniques such as agarose gel electrophoresis, researchers can generate a restriction map - a visual representation of the locations and distances between recognition sites on the DNA molecule. This information is crucial for various applications, including cloning, genome analysis, and genetic engineering.

Adenosine Triphosphate (ATP) is a high-energy molecule that stores and transports energy within cells. It is the main source of energy for most cellular processes, including muscle contraction, nerve impulse transmission, and protein synthesis. ATP is composed of a base (adenine), a sugar (ribose), and three phosphate groups. The bonds between these phosphate groups contain a significant amount of energy, which can be released when the bond between the second and third phosphate group is broken, resulting in the formation of adenosine diphosphate (ADP) and inorganic phosphate. This process is known as hydrolysis and can be catalyzed by various enzymes to drive a wide range of cellular functions. ATP can also be regenerated from ADP through various metabolic pathways, such as oxidative phosphorylation or substrate-level phosphorylation, allowing for the continuous supply of energy to cells.

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