BACILLUS

'''Bacillus''' is a genus of rod-shaped, Gram-positive bacteria and a member of the division Firmicutes. ''Bacillus'' species are either obligate or facultative aerobes, and test positive for the enzyme catalase. Bacillus. ''In:'' Barron's Medical Microbiology ''(Baron S ''et al'', eds.), Turnbull PCB, , , Univ of Texas Medical Branch, 1996, Ubiquitous in nature, ''Bacillus'' includes both free-living and pathogenic species. Under stressful environmental conditions, the cells produce oval endospores that can stay dormant for extended periods. These characteristics originally defined the genus, but not all such species are closely related, and many have been moved to other genera. Brock Biology of Microorganisms, Madigan M; Martinko J (editors)., , , Prentice Hall, 2005, ISBN 0-13-144329-1
''Bacillus subtilis'' is one of the best understood prokaryotes in terms of molecular biology and cell biology. Its superb genetic amenability and relatively large size have provided the powerful tools required to investigate a bacterium from all possible aspects. Recent improvements in fluorescence microscopy techniques have provided novel and amazing insight into the dynamic structure of a single cell organism. Research on ''Bacillus subtilis'' has been at the forefront of bacterial molecular biology and cytology, and the organism is a model for differentiation, gene/protein regulation, and cell cycle events in bacteria. Bacillus: Cellular and Molecular Biology, Graumann P (editor)., , , Caister Academic Press, 2007, ISBN 978-1-904455-12-7
Two ''Bacillus'' species are considered medically significant: ''B. anthracis'', which causes anthrax, and ''B. cereus'', which causes a foodborne illness similar to that of ''Staphylococcus''. Sherris Medical Microbiology, Ryan KJ; Ray CG (editors), , , McGraw Hill, 2004, ISBN 0-8385-8529-9 A third species, ''B. thuringiensis'', is an important insect pathogen, and is sometimes used to control insect pests. The type species is ''B. subtilis'', an important model organism. It is also a notable food spoiler, causing ropiness in bread and related food. ''B. coagulans'' is also important in food spoilage.
An easy way to isolate ''Bacillus'' is by placing non-sterile soil in a test tube with water, shaking, placing in melted Mannitol Salt Agar, and incubating at room temperature for at least a day. Colonies are usually large, spreading and irregularly-shaped. Under the microscope, the ''Bacillus'' appear as rods, and a substantial portion usually contain an oval endospore at one end, making it bulge.

Contents

The cell wall

Word ambiguity

See also

References

The cell wall

The cell wall of ''Bacillus'' is a rigid structure on the outside of the cell that forms the first barrier between the bacterium and the environment, and at the same time maintains cell shape and withstands the pressure generated by the cell's turgor. The cell wall is composed of peptidoglycan, teichoic and teichuronic acids. ''B. subtilis'' is the first bacterium for which the role of an actin-like cytoskeleton in cell shape determination and peptidoglycan synthesis was identified and for which the entire set of peptidoglycan synthesizing enzymes was localised. The role of the cytoskeleton in shape generation and maintenance is important Bacillus: Cellular and Molecular Biology ''(Graumann P, ed.), Scheffers DJ, , , Caister Academic Press, 2007, ISBN 978-1-904455-12-7 .

Word ambiguity

Although ''Bacillus'', capitalized and italicized, specifically refers to the genus, the word 'bacillus' may also be used to describe any rod-shaped bacterium, and in this sense, bacilli are found in many different taxonomic groups of bacteria.
Likewise, ''Bacilli'' refers to the particular class ''Bacillus'' belongs to, while bacilli are any rod-shaped bacteria.
It should be noted that the cell morphology term ''bacillus'' does not necessarily indicate Gram-positive staining, as ''E. coli'' is a Gram-negative, rod-shaped bacteria.

See also

★ ''Paenibacillus'', a genus of bacteria that was formerly included in ''Bacillus''

References