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Bacillus

{{Taxobox | color = lightgrey | name = Bacillus | image = Bacillus subtilis Gram.jpg | image_width = 220px | image_caption = Bacillus subtilis, Gram stained | regnum = Bacteria | divisio = Firmicutes | classis = Bacilli | ordo = Bacillales | familia = Bacillaceae | genus = Bacillus | genus_authority = Cohn, 1872 | subdivision_ranks = Species | subdivision = Bacillus anthracis
Bacillus cereus
Bacillus coagulans
Bacillus natto
Bacillus subtilis
Bacillus thuringiensis
etc. }}

Bacillus is a genusof rod-shaped bacteria. The word "bacillus" is also used to describe any rod-shaped bacterium, and in this sense, bacilli are found in many different groups of bacteria. When the particular genus Bacillus is referred to, it is capitalized and italicized. Likewise, Bacillirefers to the particular class Bacillus belongs to, while bacilli are any rod-shaped bacteria.

The genus Bacillus belongs to the Firmicutes, and like most other members has a Gram-positivestain. They are either obligate or facultative aerobes, and test positive for catalase. When conditions are stressful, the cells produce oval endosporesthat can stay dormant for extended periods. These characters originally defined the genus, but not all such species are closely related, and many have been moved to other genera.

Bacillus are ubiquitous in nature, including both free-living and pathogenic species. Two species are considered medically significant: B. anthracis, which causes anthrax, and B. cereus, which causes a foodborne illnesssimilar to that of Staphylococcus. The type speciesis B. subtilis, an important model organism. It is also a notable food spoiler, as is B. coagulans.

An easy way to isolate Bacillus is by placing non-sterile soil in a test tubewith water, shaking, placing in melted mannitol salts 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 endosporeat one end, making it bulge.

Bacillus

See also