Steroid hormones are lipophilic, low-molecular weight compounds derived from Cholesterol that play important physiological roles. The steroid hormones are synthesized mainly by Endocrine Glands such as the the Adrenal Cortex and the Gonads (Ovary and Testes), and are then released into the blood circulation. There are five major classes of steroid hormones. They are the (i) Glucocorticoids (Anti-Stress Hormones), Cortisol is the major representative in most mammals; Mineralocorticoids (Na+ Uptake Regulators), Aldosterone being most prominent; Androgens (Male Sex Hormones), such as Testosterone; Estrogens (Female Sex Hormones), including Estrodiol and Estrone; and, Progestogens (Progestational hormones), such as Progesterone. The Adrenal Cortex is responsible for[..]

Leptospira is a genus of Spirochetal bacteria and the causative agent of Leptospirosis, a zoonotic disease of worldwide distribution and transmission to humans occurs through contact with domestic or wild animal reservoirs or an environment contaminated by their urine. Leptospira is a flexible, spiral-shaped, Gram-negative Spirochete with internal flagella. Leptospira enters the host through mucosa and broken skin, resulting in Bacteremia. The Spirochetes multiply in organs, most commonly the Central Nervous System, kidneys, liver and conjunctiva. Infective bacteria are shed in the urine. These organisms establish themselves a commensal relationship with many animal hosts, persisting in the renal tubules without producing disease or causing pathologic changes in the[..]

D. psychrophila (Desulfotalea psychrophila) is a sulfate-reducing Gram-negative Delta-proteobacterium that is able to grow at temperatures below 0°C, i.e., psychrophilic and reside mostly in cold arctic marine sediments. The main mode of energy generation in D. psychrophila is sulfate reduction through fermentation. Investigating the biochemical mechanisms of such sulfate-reducing psychrophilic bacteria is vital for understanding the functioning of global biogeochemical cycles. The metabolism of vital amino acids like Glycine, Serine and Threonine acts as one of the many sources that provide carbon or energy to D. psychrophila in form of intermediates like Pyruvate, etc (Ref.1 & 2). During Serine metabolism L-Serine is interconverted into Pyruvate by L-Serine[..]

R. baltica (Rhodopirellula baltica) is a marine, aerobic, heterotrophic representative of the globally distributed and environmentally important bacterial order Planctomycetales. They catalyze important transformations in global carbon and nitrogen cycles. From a phylogenetic perspective the order Planctomycetales forms an independent, monophyletic phylum of the domain Bacteria. These are thought to be the deepest branching bacterial phylum. Planctomycetes are unique in many other respects. Their cell walls do not contain peptidoglycan, the main structural polymer of most members of the domain Bacteria. They show a unique cell compartmentalization in which a single membrane separates a peripheral ribosome-free paryphoplasm from the inner riboplasm (pirellulosome).[..]

Rhizobium, Bradyrhizobium, Mesorhizobium, Sinorhizobium, and Azorhizobium-collectively known as rhizobia, are Gram-negative, nitrogen-fixing bacteria of agronomic importance because they perform nitrogen-fixing symbioses with leguminous plants (soybean, alfalfa, beans, peas, etc). The metabolism of amino acids like Glycine is indispensable for functioning of one-carbon metabolism and for the establishment of a fully effective, nitrogen-fixing root nodule symbiosis in M. loti (Mesorhizobium loti). Glycine acts as a source of other vital amino acids like L-Serine and L-Threonine. It also contributes to the one-carbon pool, to formation of Glutathione, to Purine nucleotides, and to Porphyrins. Purine Metabolism may also form a source of Glycine. Direct routes of Glycine[..]

Species in the genus Brucella are the etiological agents of Brucellosis, a zoonotic disease endemic in many areas of the world, characterized by chronic infections in animals leading to abortion and infertility, and a systemic, febrile illness in humans. Brucella is facultative intracellular pathogens that enter the host through mucosal surfaces and are able to survive inside macrophages. B. suis (Brucella suis) is the first Gram-negative pathogenic organism weaponized as a potential bioterrorism agent (Ref.1). The presence of S-LPS (Smooth Lipopolysaccharide) is an important virulence factor of these organisms. The role of the O-side chain or O-antigen of S-LPS in the survival of Brucella has not been clearly defined; however it might provide a protective mechanism in[..]

B. melitensis (Brucella melitensis) is a Gram-negative, aerobic, facultative intracellular bacterial pathogen that causes abortion in goats and sheep and Malta fever in humans. Species in the genus Brucella are the etiological agents of Brucellosis, a zoonotic disease endemic in many areas of the world, characterized by chronic infections in animals leading to abortion and infertility, and a systemic, febrile illness in humans. Brucella is facultative intracellular pathogens that enter the host through mucosal surfaces and are able to survive inside macrophages (Ref.1 & 2). The presence of S-LPS (Smooth Lipopolysaccharide) is an important virulence factor of these organisms. The role of the O-side chain or O-antigen of S-LPS in the survival of Brucella has not been[..]

The genus Yersinia is known to include eleven species, three of which are potentially pathogenic to humans; Y. pestis (Yersinia pestis), Y. pseudotuberculosis (Yersinia pseudotuberculosis), and Y. enterocolitica (Yersinia enterocolitica). Y. pseudotuberculosis is a Gram-negative Coccobacillus belonging to the family Enterobacteriaceae. The designation pseudotuberculosis derives from the characteristic histopathological aspect occurring in mesenteric lymph nodes of Lymphoid Hyperplasia cases which closely resemble those observed during tuberculosis infection (Ref.1). Y. pseudotuberculosis is widely spread in the environment (soil, water, vegetables, etc). This bacterium is a primary pathogen of wild and domestic animals in all continents. Nearly all animal species are[..]

The metabolism of Glycine, Serine and Threonine is essential for the unicellular eukaryote S. pombe (Schizosaccharomyces pombe), as it uses L-Serine or L-Threonine as sole nitrogen source for its survival. During the metabolism of these amino acids, L-Threonine is generally synthesized from Pyruvate and L-Aspartate. The enzyme Threonine Ammonia Lyase/Threonine Dehydratase converts Pyruvate (from Pyruvate metabolism) to amino acids like L-Serine. Serine Hydroxymethyltransferase/Glycine Hydroxymethyltransferase then catalyzes the THF (Tetrahydrofolate) dependent cleavage of L-Serine to Glycine and 5,10-Methylene-THF (5,10-Methylenetetrahydrofolate). Serine Hydroxymethyltransferase is the major provider of one-carbon units in the cell, which are derived from catabolism of[..]

Y. pestis (Yersinia pestis) is rod shaped, Gram-negative, and non-motile but has two distinct flagellar gene clusters; one set is incomplete and the other produces a truncated protein, which acts as a transcriptional activator for the flagellar genes. Y. pestis, a Group-A bioterrorism agent, causes Plague, a re-emerging zoonotic disease transmitted to humans through flea bites and typically characterized by the appearance of a tender and swollen lymph node, the bubo. It is believed that Y. pestis is a clone that evolved from Y. pseudotuberculosis (Yersinia pseudotuberculosis) about 1.5 to 20 thousand years ago. Y. pestis is primarily a rodent pathogen, with humans being an accidental host when bitten by an infected rat flea (Ref.1). The rodents’ fleas, such as[..]

S. cerevisiae (Saccharomyces cerevisiae) are single-celled fungi which multiply by budding or in some cases by division (fission). Yeast fermentations comprise the oldest and largest application of microbial technology. Yeast physiology can be either obligately aerobic or facultatively fermentative. There is no known obligately anaerobic yeast. In pharmacy and chemistry, a large number of substances (Vitamins and enzymes) are extracted from this organism. In addition, some medications are now produced by manipulated yeasts, for example vaccines against Hepatitis-B surface antigen are produced by S. cerevisiae utilizing recombinant technology. The metabolism of Glycine, Serine and Threonine in S. cerevisiae is of vital importance as they use L-Serine or L-Threonine as[..]

T. tengcongensis (Thermoanaerobacter tengcongensis) is a rod-shaped, Gram-negative, anaerobic eubacterium that metabolizes sugars as the principal source of energy and carbon source, and gains energy anaerobically by Sulfur respiration. T. tengcongensis has a complete collection of genes involved in most of the amino acid biosynthetic pathways for Threonine, Valine, Leucine, Histidine, Phenylalanine/Tyrosine, Tryptophan, Arginine and Methionine. However, it lacks a few key genes such as Threonine Dehydratase for Isoleucine biosynthesis and Ornithine Cyclodeaminase for Proline biosynthesis. For nucleotide metabolism, it also has a complete set of genes for Purine biosynthesis, Purine salvage, and Pyrimidine biosynthesis pathways (Ref.1). In the direction of L-Threonine[..]