Geobacillus kaustophilus HTA426, which was isolated from the deep-sea sediment of the Mariana Trench, is a thermophilic Bacillus-related species whose upper temperature limit for growth is 74 degrees Celsius (optimally 60 degrees Celsius). It is known that there are at least 12 other thermophilic Geobacillus species, which have been reclassified from the genus Bacillus (Ref.1).The cell wall of these bacteria is a unique biopolymer, containing both D- and L-Amino acids. The terminal peptide is D-Alanine although other amino acids are present as D- isomers and this is the only known biological molecule that contains D-Amino acids, which are responsible for the building of peptidoglycan. A key step in peptidoglycan layer assembly and deposition is the subsequent enzymic[..]

The bacterial genus Listeria is currently taxonomically subdivided into six species: L. monocytogenes, L. seeligeri, L. ivanovii, L. innocua, L. grayi, and L. welshimeri. Two of the species are pathogenic, causing the disease listeriosis. L. innocua is widespread in the environment and in food. The only phenotypic characteristic that classically distinguishes L. monocytogenes from L. innocua is hemolysis (Ref.1).As in most Gram-positive bacteria, the cell wall of L. monocytogenes is composed of a thick peptidoglycan containing two types of anionic polymers: (i) the TAs (Teichoic Acids), which are covalently linked to the peptidoglycan; and (ii) the LTAs (Lipoteichoic Acids), which are polyphosphoglycerol substituted with a D-Ala (D-Alanyl) ester or a glycosyl residue[..]

Brucella is a Gram-negative aerobic pathogen that is distringuished from most other pathogens because it does not have "obvious virulence factors" like capsules, fimbriae, flagella, exotoxins, exproteases, or other exoenzymes, cytolysins, resistance forms, antigenic variation, plamids, or lysogenic phages. Brucella sp. causes 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 melitensis is the cause of brucellosis in goats, cattle, sheep, pigs, dogs, marine mammals, and several wild animals. Goats are the natural hosts for B. melitensis. This bacterium is also the cause of a rarer, more severe systemic[..]

Rhizobium, Bradyrhizobium, Mesorhizobium, Sinorhizobium and Azorhizobium-known as Rhizobia-are Gram-negative, nitrogen-fixing bacteria of agronomic importance because they perform nitrogen-fixing symbiosis with leguminous plants. They are responsible for the world’s largest portion of fixed atmospheric nitrogen. Bradyrhizobium japonicum(B. japonicum) has been used since 1957 in molecular genetics, physiology, and ecology due to its excellent ability in symbiotic nitrogen fixation. Nodule formation and the subsequent nitrogen-fixation result from a series of interactions controlled by the exchange of molecular signals between symbiotic bacteria and host plants followed by expression of genes from both symbiotic partners. B. japonicum is able to form[..]

Group-A Streptococcus pyogenes remains an important human pathogen responsible for a variety of suppurative infections, including pharyngitis, scarlet fever, impetigo, and cellulitis and for nonsuppurative sequelae, such as acute rheumatic fever, acute Glomerulonephritis, and reactive arthritis (Ref.1). S. pyogenes strains are grouped into two classes on the basis of post infectious sequelae associated with each strain, Class-I is responsible for rheumatic fever and Class-II is responsible for acute glomerulonephritis. S. pyogenes strain MGAS8232 (Serotype M18) was isolated from a patient with acute rheumatic fever. The Serotype M18 is among the most prevalent in terms of involvement in severe invasive infections (Ref.2, 3 & 4).As is the case in other Gram-positive[..]

Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica are closely related Gram-negative Beta-proteobacteria that colonizes the respiratory tracts of mammals. B. bronchiseptica causes chronic respiratory infections in a wide range of animals. D-Alanine is a necessary precursor in the biosynthesis of cell wall in this bacterium (Ref.1).The naturally occurring L-Alanine isomer is racemized to its D-form through the action of a class of enzymes called alr (alanine racemase).using Pyridoxal 5'-Phosphate (Vitamin-B6) as a cofactor (Ref.2). L-Alanine is also a product of several other metabolic pathways like Cyanoamino Acid Metabolism, Selenoamino Acid Metabolism, Alanine and Aspartate, and D-Arginine and D-Ornithine Metabolism. D-Alanine metabolism[..]

The genus Bordetella in the family Alcaligenaceae, comprises five species(Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica, Bordetella hinzii and Bordetella avium ), four of which cause infections of the upper respiratory tract in different host organisms. They are closely related Gram-negative Beta-proteobacteria Bordetella pertussis is an obligate human pathogen and is the etiological agent of whooping cough (pertussis), an acute respiratory infection more serious among infants. Annually, more than 50 million cases of pertussis, including 600,000 deaths are reported worldwide. Bordetella parapertussis, causes a mild pertussis-like disease in humans and is very closely related to B. pertussis. An animal pathogen of the Bordetella species is[..]

Bacillus species and other microbes with pH optima for growth higher than pH 9 are defined as alkaliphiles. A large number of alkaliphilic Bacillus strains producing useful enzymes, have been isolated from various environments. Bacillus halodurans(B. halodurans) is an alkaliphilic Bacillus species that grows optimally above pH 9.5. It is the second Bacillus species whose entire genomic sequence has been completely defined. B. halodurans is similar to B. subtilis in terms of genome size, G+C content, and physiological properties, except for its alkaliphilic phenotype (Ref.1).The cell wall of these Gram-positive bacteria is a unique biopolymer, containing both D- and L-Amino acids. Its basic structure is a carbohydrate backbone of alternating units of N-Acetyl[..]

Bacilli are an extremely diverse group of bacteria that include both the causative agent of anthrax (Bacillus anthracis) as well as several species that synthesize important antibiotics. Bacilli are rod-shaped, Gram-positive, sporulating, aerobes or facultative anaerobes. Bacilli exhibit an array of physiologic abilities that allow them to live in a wide range of habitats, including many extreme habitats such as desert sands, hot springs, and Arctic soils. Species in the genus Bacillus can be thermophilic, psychrophilic, acidophilic, alkaliphilic, halotolerant, or halophilic and are capable of growing at pH values, temperatures, and salt concentrations where few other organisms can survive. Due to the metabolic diversity in the genus Bacillus, Bacilli are able to[..]

Bacilli are an extremely diverse group of bacteria that include both the causative agent of anthrax (Bacillus anthracis) as well as several species that synthesize important antibiotics. Bacilli are rod-shaped, Gram-positive, sporulating, aerobes or facultative anaerobes. Bacilli exhibit an array of physiologic abilities that allow them to live in a wide range of habitats, including many extreme habitats such as desert sands, hot springs, and Arctic soils. Species in the genus Bacillus can be thermophilic, psychrophilic, acidophilic, alkaliphilic, halotolerant, or halophilic and are capable of growing at pH values, temperatures, and salt concentrations where few other organisms can survive (Ref.1, 2 & 4). Due to the metabolic diversity in the genus Bacillus,[..]

Bacilli are rod-shaped, Gram-positive, sporulating, aerobes or facultative anaerobes. Bacilli exhibit an array of physiologic abilities that allow them to live in a wide range of habitats, including many extreme habitats such as desert sands, hot springs, and Arctic soils. Species in the genus Bacillus can be thermophilic, psychrophilic, acidophilic, alkaliphilic, halotolerant, or halophilic and are capable of growing at pH values, temperatures, and salt concentrations where few other organisms can survive (Ref.1, 2 and 4). Due to the metabolic diversity in the genus Bacillus, Bacilli are able to colonize a variety of habitats ranging from soil to insects, to humans. The three species of the Group-1 Bacilli, B. anthracis, B. cereus, and B. thuringiensis, are[..]

Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica are closely related Gram-negative Beta-proteobacteria that colonizes the respiratory tracts of mammals. B. pertussis is a strict human pathogen of recent evolutionary origin and is the primary etiologic agent of whooping cough. D-Alanine is a necessary precursor in the biosynthesis of cell wall in this bacterium (Ref.1). The naturally occurring L-Alanine isomer is racemized to its D-form through the action of a class of enzymes called AlRs (Alanine Racemase). This enzyme is ubiquitous among prokaryotes and with very few exceptions are absent in eukaryotes (Ref.2). It catalyzes the racemization of L-Alanine and D-Alanine, using Pyridoxal 5'-Phosphate as a cofactor and is involved in[..]