The Genus Bacillus (page 6)
(This chapter has 6 pages)
© Kenneth Todar, PhD
4. Characteristics of
Bacillus and related aerobic
Thermoacidophile. Limits of
for growth are 45o and 65oC. The
limits of pH for growth around 2. Found in hot acidic environments.
Spores have surprisingly weak thermal resistance.
Bacillus alcalophilus Alkaliphile. Tolerant to alkaline
and does not grow at pH 7. Capable of growth at pH >10.
alvei Isolated from soil and from honeybee larvae
suffering from European foulbrood disease. Not classified as an insect
Bacillus anthracis The causative agent of anthrax in
and in animals. Spores persist for long periods on contaminated
Bacillus azotoformans. Has a negative Gram reaction. Can
anaerobically using NO3, NO2, SO4 or
as a final electron acceptor. A vigorous denitrifying bacterium in
it converts NO3, NO2 and N2O to large
amounts of N2.
Bacillus badius Forms a distinct colony with rhizoid
Has been isolated from feces, dust, marine sources, foods and antacids.
Brevibacillus brevis Has been isolated chiefly from soils
Requires a mixture of amino acids without vitamins for growth.
Bacillus cereus A close relative of B. anthracis, B.
and B. thuringiensis. Spores are widespread in soil and air.
observed multiplying in foods such as cooked rice and may lead to food
poisoning. Produces antibiotics.
Bacillus circulans Some strains are cellulolytic. Has a
Bacillus coagulans Includes acidophilic strains. Spores
relatively sparse in soils. May multiply in acid foods such as canned
juice and silage. Found in medicated creams and antacids
Bacillus fastidiosis Uses only uric acid,
acid or allantoin as an energy source. Isolated from soil and from
Bacillus firmus Isolated chiefly from soil. Pigmented
occur in salt marshes.
Sporosarcina globisporus Forms spherical spores. Found in
soil and river water.
Bacillus insolitus Growth and sporulation occur at 0
Vegetative cells are short and stout. Found in Arctic soils.
larvae Causes American foulbrood in honeybees.
Brevibacillus laterosporus Produces a canoe-like body
the side of spore forcing the spore into a lateral position in the
Rarely isolated, but has been found in dead honeybee larvae, soil,
lentimorbus More fastidious nutritionally and more
widespread than P. popilliae, it also infects the Japanese
and the European chafer. Isolated from diseased larvae or infected
Bacillus lentus Similar to B. firmus, but more
Isolated from soil, food and spices.
Bacillus licheniformis Produces same type of
capsule as B. anthracis. Red pigment produced by many strains.
occur in soil. Growth in foods, especially if held between 30 and 50
Industrial source of bacitracin, a medically useful antibiotic.
macerans Most strains fix N2 under anaerobic
conditions. Degrades pectin and plant polysaccharides. Some strains
thermophilic. Also has been found in canned fruit at pH 3.8.
macquariensis Grows and sporulates at 0 degrees. Otherwise
similar to B. circulans.
Marinibacillus marinus Grows at 5-30 degrees but not at
Has an obligate requirement for Na+. Isolated routinely from
Bacillus megaterium "Megaterium" means "big beast".
largest cell diameter of any aerobic spore former (1.2 -1.5
Grows in minimal medium without any added growth factors. Spores are
in soil. Subject of many basic studies of Gram-positive bacteria in the
Bacillus mycoides Similar to B. cereus but
motile, and forms distinctive rhizoid colonies. High degree of
with B. anthracis, B. cereus and B. thuringiensis.
Sporosarcina pasteurii Converts
urea to ammonium carbonate more
actively than any known bacterium. Requires alkaline medium (pH 9) for
growth. Isolated from soil, water, sewage and encrustations on urinals.
Paenibacillus polymyxa Colonies are mucoid,
slimy and tend to spread.
Synthesizes profuse levan capsule from sucrose. Spores have
surface ridges so are star-shaped in cross-section. Degrades pectin and
plant polysaccharides. Nitrogen fixed under anaerobic conditions.
are widespread. Multiplication occurs chiefly in decaying vegetation.
isolated from foods. Found in medicated creams and antacids. Source of
the antibiotic polymyxin. A very versatile and widespread sporeformer.
Paenibacillus popilliae Pathogen of scarabeid
beetles that causes
(one variety of) milky disease in the Japanese beetle. Together with B.
lentimorbus, it is a biological agent for the Japanese beetle and
European chafer. The larvae become milky white because of the prolific
production of spores in the insect hemolymph. Forms a distinctive
crystal that distinguishes it from B. lentimorbus. Isolated
hemolymph of Japanese beetle grubs.
Bacillus pumilus Spores are ubiquitous; occurs in soil
frequently than those of B. subtilis.
Bacillus schlegelii Thermophile similar to B.
sphaericus in its high G+C content, but differentiated because it
is a facultative lithoautotroph. The bacterium can
derive energy from the oxidation of H2 or CO while obtaining
carbon from either CO2 or CO. Isolated from lake sediments
sugar factory sludge.
Bacillus sphaericus Isolated from soil, marine and fresh
sediments, milk and foods.
Geobacillus stearothermophilus Grows at 65o C
tolerance to acid. Occurs in soil, hot springs, desert sand, Arctic
ocean sediments, food and compost.
Bacillus subtilis Grows as a unicellular rod, seldom as
Degrades pectin and polysaccharides in plant tissues, and some strains
cause rots in live potato tubers. Grows in a minimal defined medium
no added growth factors. Endospores are widespread. Vegetative
take part in various stages in the early breakdown of materials of
and animal origin. Grows in non acid food under aerobic conditions.
agent of ropy (slimy) bread. This bacterium is the experimental "E. coli" of
bacteria. Much of the information we have on the biology, biochemistry
and genetics of the Gram-positive cell, indeed, of bacteria in general,
has been derived from the study of B. subtilis.
Bacillus thuringiensis Distinguished from B. cereus
by pathogenicity for lepidopteran insects, and production of a
crystal in association with spore formation. In the larval gut, the
(crystal) is toxic. The spores and crystals are marketed in garden
as BT, for biological control of lepidopterans that attack garden and
Bt is encoded on a plasmid which can be spontaneously transferred to
cereus, endowing it with the ability to produce the toxic
Some taxonomists have argued that this is evidence of such a close
relationship between the two bacteria that B. thuringiensis
be considered a variant subspecies of B. cereus. The same
has been made for the relationship between B. anthracis,
plasmid-encoded anthrax toxin, and B. cereus.
END OF CHAPTER
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