''Bacillus mycoides'' is a

bacterium Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among the ...

of the genus ''

Bacillus ''Bacillus'', from Latin "bacillus", meaning "little staff, wand", 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-sh ...

''. Like other ''Bacillus'' species, ''B. mycoides'' is

Gram positive In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. The Gram stain i ...

rod-shaped Bacterial cellular morphologies are the shapes that are characteristic of various types of bacteria and often key to their identification. Their direct examination under a light microscope enables the classification of these bacteria (and archae ...

, and forms

spores In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plant ...

. ''B. mycoides'' is distinguished from other ''Bacillus'' species by its unusual growth on agar plates, where it forms expansive hairy colonies with characteristic swirls.

Description

''B. mycoides'' are rod-shaped cells about 1

micron The micrometre (English in the Commonwealth of Nations, Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a uni ...

across and 3 to 5 microns long. When growing, they either grow as single cells or form loosely connected chains of cells. They are not motile. ''B. mycoides'' can survive with or without oxygen and grows at temperatures ranging from 10 to 15 °C to 35–40 °C. ''B. mycoides'' is distinguished from a number of other ''Bacillus'' species in the unusual morphology of the colonies it forms when grown on

agar Agar ( or ), or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae, primarily from " ogonori" and " tengusa". As found in nature, agar is a mixture of two components, t ...

plates. ''B. mycoides'' forms white opaque colonies that are characteristically hairy in appearance (often referred to as "rhizoid"). These colonies rapidly spread to fill the plate and are characterized by a repeating spiral pattern.Di Franco, C., Beccari, E., Santini, T., Pisaneschi, G., & Tecce, G. 2002. Colony shape as a genetic trait in the pattern-forming ''Bacillus mycoides''. BMC Microbiol. 2, 33. ''B. mycoides'' has the unusual property of being able to respond to mechanical force and surface structure variations in the media on which it is growing.

Ecology and distribution

''B. mycoides'' is present in a wide variety of environments, especially soil.

Role in disease

''B. mycoides'' are capable of causing disease in some fish, and were the reported cause of an outbreak of

necrotic Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who is ...

lesions in

channel catfish The channel catfish (''Ictalurus punctatus''), known informally as the "channel cat", is a species of catfish native to North America. They are North America's most abundant catfish species, and the official state fish of Kansas, Missouri, Nebra ...

in a commercial pond in

Alabama Alabama ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South, Deep Southern regions of the United States. It borders Tennessee to the north, Georgia (U.S. state), Georgia to the east, Florida and the Gu ...

''B. weihenstephanensis''

In 1998 a new ''Bacillis'' species was described, and named ''Bacillus weihenstephanensis''. However, twenty years later, a comparison of the complete genome sequences of ''B. weihenstephanensis'' and ''B. mycoides'' demonstrated that ''B. weihenstephanensis'' was a later synonym for ''B. mycoides'', and thus not a valid species, nor species name.

References

External links