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Bacillus is a genus of Gram-positive, rod-shaped bacteria, a member of the phylum Bacillota, with 266 named species. The term is also used to describe the shape (rod) of other so-shaped bacteria; and the plural Bacilli is the name of the class of bacteria to which this genus belongs. Bacillus species can be either obligate aerobes which are dependent on oxygen, or facultative anaerobes which can survive in the absence of oxygen. Cultured Bacillus species test positive for the enzyme catalase if oxygen has been used or is present.
An endospore is a dormant, tough, and non-reproductive structure produced by some bacteria in the phylum Bacillota. The name "endospore" is suggestive of a spore or seed-like form, but it is not a true spore. It is a stripped-down, dormant form to which the bacterium can reduce itself. Endospore formation is usually triggered by a lack of nutrients, and usually occurs in gram-positive bacteria. In endospore formation, the bacterium divides within its cell wall, and one side then engulfs the other. Endospores enable bacteria to lie dormant for extended periods, even centuries. There are many reports of spores remaining viable over 10,000 years, and revival of spores millions of years old has been claimed. There is one report of viable spores of Bacillus marismortui in salt crystals approximately 250 million years old. When the environment becomes more favorable, the endospore can reactivate itself into a vegetative state. Most types of bacteria cannot change to the endospore form. Examples of bacterial species that can form endospores include Bacillus cereus, Bacillus anthracis, Bacillus thuringiensis, Clostridium botulinum, and Clostridium tetani. Endospore formation is not found among Archaea.
Bacillus megaterium is a rod-like, Gram-positive, mainly aerobic, spore forming bacterium found in widely diverse habitats. It has a cell length up to 4 µm and a diameter of 1.5 µm, which is quite large for bacteria. The cells often occur in pairs and chains, where the cells are joined together by polysaccharides on the cell walls.
Sphingomyelin phosphodiesterase is a hydrolase enzyme that is involved in sphingolipid metabolism reactions. SMase is a member of the DNase I superfamily of enzymes and is responsible for breaking sphingomyelin (SM) down into phosphocholine and ceramide. The activation of SMase has been suggested as a major route for the production of ceramide in response to cellular stresses.
Subtilisin is a protease initially obtained from Bacillus subtilis.
Aspartic proteases are a catalytic type of protease enzymes that use an activated water molecule bound to one or more aspartate residues for catalysis of their peptide substrates. In general, they have two highly conserved aspartates in the active site and are optimally active at acidic pH. Nearly all known aspartyl proteases are inhibited by pepstatin.
BglII is a type II restriction endonuclease isolated from certain strains of Bacillus globigii.
In enzymology, a CoA-disulfide reductase (EC 1.8.1.14) is an enzyme that catalyzes the chemical reaction
Spore photoproduct lyase is a radical SAM enzyme that repairs DNA cross linking of thymine bases caused by UV-radiation. There are several types of thymine cross linking, but SPL specifically targets 5-thyminyl-5,6-dihydrothymine, which is also called spore photoproduct (SP). Spore photoproduct is the predominant type of thymine crosslinking in germinating endospores, which is why SPL is unique to organisms that produce endospores, such as Bacillus subtilis. Other types of thymine crosslinking, such as cyclobutane pyrimidine dimers (CPD) and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs), are less commonly formed in endospores. These differences in DNA crosslinking are a function of differing DNA structure. Spore genomic DNA features many DNA binding proteins called small acid soluble proteins, which changes the DNA from the traditional B-form conformation to an A-form conformation. This difference in conformation is believed to be the reason why dormant spores predominantly accumulate SP in response to UV-radiation, rather than other forms of cross linking. Spores cannot repair cross-linking while dormant, instead the SPs are repaired during germination to allow the vegetative cell to function normally. When not repaired, spore photoproduct and other types of crosslinking can cause mutations by blocking transcription and replication past the point of the crosslinking. The repair mechanism utilizing spore photoproduct lyase is one of the reasons for the resilience of certain bacterial spores.
Tyndallization is a process from the nineteenth century for sterilizing substances, usually food, named after its inventor John Tyndall, that can be used to kill heat-resistant endospores. Although now considered dated, it is still occasionally used.
Subtilases are a family of subtilisin-like serine proteases. They appear to have independently and convergently evolved an Asp/Ser/His catalytic triad, like in the trypsin serine proteases. The structure of proteins in this family shows that they have an alpha/beta fold containing a 7-stranded parallel beta sheet.
Bacillus pumilus is a Gram-positive, aerobic, spore-forming bacillus commonly found in soil.
Leumorphin, also known as dynorphin B1–29, is a naturally occurring endogenous opioid peptide. Derived as a proteolytic cleavage product of residues 226-254 of prodynorphin, leumorphin is a nonacosapeptide and has the sequence Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Gln-Phe-Lys-Val-Val-Thr-Arg-Ser-Gln-Glu-Asp-Pro-Asn-Ala-Tyr-Ser-Gly-Glu-Leu-Phe-Asp-Ala. It can be further reduced to dynorphin B and dynorphin B-14 by pitrilysin metallopeptidase 1, an enzyme of the endopeptidase family. Leumorphin behaves as a potent and selective κ-opioid receptor agonist, similarly to other endogenous opioid peptide derivatives of prodynorphin.
Steroid 15beta-monooxygenase (EC 1.14.15.8, cytochrome P-450meg, cytochrome P450meg, steroid 15beta-hydroxylase, CYP106A2, BmCYP106A2) is an enzyme with systematic name progesterone,reduced-ferredoxin:oxygen oxidoreductase (15beta-hydroxylating) . This enzyme catalyses the following chemical reaction
Gamma-D-glutamyl-meso-diaminopimelate peptidase is an enzyme. This enzyme catalyses the following chemical reaction
Glutamyl endopeptidase II is an enzyme. This enzyme catalyses the following chemical reaction
Nuclear-inclusion-a endopeptidase is a protease enzyme found in potyviruses. This enzyme catalyses the following chemical reaction:
Calicivirin is an enzyme. This enzyme catalyses the following chemical reaction
Bacillolysin is an enzyme. This enzyme catalyses the following chemical reaction
Glutamyl endopeptidase I is a family of extracellular bacterial serine proteases. The proteases within this family have been identified in species of Staphylococcus, Bacillus, and Streptomyces, among others. The two former are more closely related, while the Streptomyces-type is treated as a separate family, glutamyl endopeptidase II.
References
- ↑ Ponnuraj K, Rowland S, Nessi C, Setlow P, Jedrzejas MJ (June 2000). "Crystal structure of a novel germination protease from spores of Bacillus megaterium: structural arrangement and zymogen activation". Journal of Molecular Biology. 300 (1): 1–10. doi:10.1006/jmbi.2000.3849. PMID 10864493.
