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| Bacillus thuringiensis cells by Gram staining (left) and spores outside vegetative cells by Malachite green staining (right) |
Insect larvae pathogen (mosquito, Lepidoptera etc.) by toxins synthesis. Used as bio-
pesticide. Some strains of B. thuringiensis may produce the B. cereus diarrheal toxin.
Delta-endotoxins or insecticidal crystal proteins are protoxins which may be toxic for
certain insects and other invertebrates including flatworms, mites, nematodes and
protozoa. The ability to synthesize parasporal bodies is plasmid borne. There is little
correlation between serotype and insecticidal toxicity.
Although numerous strains are toxic to invertebrates, this property has not been
demonstrated in many other strains. Natural epizootics do not seem to occur, and it
has been suggested that the natural habitat of this organism is soil.
B. thuringiensis has been implicated in cases of gastroenteritis and wound, burn and
ocular infections.
pesticide. Some strains of B. thuringiensis may produce the B. cereus diarrheal toxin.
Delta-endotoxins or insecticidal crystal proteins are protoxins which may be toxic for
certain insects and other invertebrates including flatworms, mites, nematodes and
protozoa. The ability to synthesize parasporal bodies is plasmid borne. There is little
correlation between serotype and insecticidal toxicity.
Although numerous strains are toxic to invertebrates, this property has not been
demonstrated in many other strains. Natural epizootics do not seem to occur, and it
has been suggested that the natural habitat of this organism is soil.
B. thuringiensis has been implicated in cases of gastroenteritis and wound, burn and
ocular infections.
Bichemical characters cannot be used to differentiate between or within serovars.
Bacillus thuringiensis serovars by H antigens:
Bacillus thuringiensis serovars by H antigens:
| Bacillus thuringiensis |
Biochemical characters
| Bacillus thuringiensis colonies on Sheep Blood Agar; beta-haemolysis |
Taxonomy
Morphology
Cultural characteristics
Ecology
Pathogenicity
References
Phylum Firmicutes, Class Bacilli, Order Bacillales, Family Bacillaceae, Genus Bacillus, Bacillus thuringiensis Berliner (1915)
Synonym: Bacillus cereus var. thuringiensis Smith, Gordon and Clarck (1952).
Hystorical synonyms: B. cereus var. alesti Toumanoff and Vago (1951), B. dendrolimus Talalaev (1956), B. entomocidus var.
entomocidus Heimpel and Angus (1958), B. entomocidus var. subtoxicus Heimpel and Angus (1958), B. ephestiae ( Metalnikov and
Chorine ,1929) Steinhaus (1949), B. finitimus Heimpel and Angus (1958), B. soto Metalnikov and Chorine (1927), B. bombycis
Macchiati (1891), B. anagastae Heimpel (1967), B. tolworthi de Barjac and Bonnefoi (1968), B. darmstadiensis Krieg, de Barjac and
Bonnefoi (1968), B. toumanoffii Krieg (1969), B. morrisoni de Barjac and Bonnefoi (1968), B. aizawai Hempel (1967), B. pacificus
Hempel (1967), B. galleriae Hempel (1967), B. kenyae de Barjac and Bonnefoi (1967), B. amuscatoxicus Hempel (1967).
Phenotypically very close to other members of the Bacillus cereus group: Bacillus anthracis, Bacillus mycoides, Bacillus
pseudomycoides, Bacillus cereus and Bacillus weihenstephanensis. Genetic evidence supports the recognition of members of the
Bacillus cereus group as one species, but practical considerations (virulence characters) argue against such a move. Bacillus
thuringiensis is distinguished by its characteristic parasporal crystals. Smith et al. (1952) and Gordon et al. (1973) considered
Bacillus thuringiensis to be a variety of Bacillus cereus.
Bacillus thuringiensis has been divided on the basis of flagellar (H) antigens into 69 serotypes with 13 subantigenic groups, giving a
total of 82 serovars (Lecadet et al., 1999).
Synonym: Bacillus cereus var. thuringiensis Smith, Gordon and Clarck (1952).
Hystorical synonyms: B. cereus var. alesti Toumanoff and Vago (1951), B. dendrolimus Talalaev (1956), B. entomocidus var.
entomocidus Heimpel and Angus (1958), B. entomocidus var. subtoxicus Heimpel and Angus (1958), B. ephestiae ( Metalnikov and
Chorine ,1929) Steinhaus (1949), B. finitimus Heimpel and Angus (1958), B. soto Metalnikov and Chorine (1927), B. bombycis
Macchiati (1891), B. anagastae Heimpel (1967), B. tolworthi de Barjac and Bonnefoi (1968), B. darmstadiensis Krieg, de Barjac and
Bonnefoi (1968), B. toumanoffii Krieg (1969), B. morrisoni de Barjac and Bonnefoi (1968), B. aizawai Hempel (1967), B. pacificus
Hempel (1967), B. galleriae Hempel (1967), B. kenyae de Barjac and Bonnefoi (1967), B. amuscatoxicus Hempel (1967).
Phenotypically very close to other members of the Bacillus cereus group: Bacillus anthracis, Bacillus mycoides, Bacillus
pseudomycoides, Bacillus cereus and Bacillus weihenstephanensis. Genetic evidence supports the recognition of members of the
Bacillus cereus group as one species, but practical considerations (virulence characters) argue against such a move. Bacillus
thuringiensis is distinguished by its characteristic parasporal crystals. Smith et al. (1952) and Gordon et al. (1973) considered
Bacillus thuringiensis to be a variety of Bacillus cereus.
Bacillus thuringiensis has been divided on the basis of flagellar (H) antigens into 69 serotypes with 13 subantigenic groups, giving a
total of 82 serovars (Lecadet et al., 1999).
Gram positive, 1.1 -1.2 x 3.0-5.0 μm, motile rods. Ellipsoidal, central or paracentral
spore, not deforming the sporangia appreciably. Spores may be cylindrical and may
be positioned subterminally. Spores may lie obliquely in the sporangia. No capsule
present.
Parasporal bodies within the sporangia. These crystalline protein inclusions may be
bipyramidal, cuboid, spherical to ovoid, flat-rectangular, or heteromorphic in shape.
They are formed outside the exosporium and readily separate from the liberated
spore. They are known as delta-endotoxins or insecticidal crystal proteins.
The bacilli tend to occur in chains. Cells grown on glucose agar produce large
amounts of storage material, giving a vacuolate or foamy appearance.
The presence of crystals is the major criterion for distinguishing between B. cereus
and B. thuringiensis.
spore, not deforming the sporangia appreciably. Spores may be cylindrical and may
be positioned subterminally. Spores may lie obliquely in the sporangia. No capsule
present.
Parasporal bodies within the sporangia. These crystalline protein inclusions may be
bipyramidal, cuboid, spherical to ovoid, flat-rectangular, or heteromorphic in shape.
They are formed outside the exosporium and readily separate from the liberated
spore. They are known as delta-endotoxins or insecticidal crystal proteins.
The bacilli tend to occur in chains. Cells grown on glucose agar produce large
amounts of storage material, giving a vacuolate or foamy appearance.
The presence of crystals is the major criterion for distinguishing between B. cereus
and B. thuringiensis.
On agar, colonies are very variable in appearance. They are usually whitish to cream
in color, large (2-7 mm in diameter), and vary in shape from circular to irregular, with
entire to undulate, crenate or fimbriate edges; they usually have matt or granular
textures. Sometimes smooth and moist colonies may appear.
Growth temperature from 10-15 ºC to 40-45 ºC. Grows in 0-7% NaCl and at pH 5,7
and 7. Allantoin or urate are not required. Grows on nutrient agar or nutrient broth.
in color, large (2-7 mm in diameter), and vary in shape from circular to irregular, with
entire to undulate, crenate or fimbriate edges; they usually have matt or granular
textures. Sometimes smooth and moist colonies may appear.
Growth temperature from 10-15 ºC to 40-45 ºC. Grows in 0-7% NaCl and at pH 5,7
and 7. Allantoin or urate are not required. Grows on nutrient agar or nutrient broth.
Endospores are widespread in soil and many other environments. The organism has been isolated from all continents, including
Antarctica.
The ability to produce parasporal bodies has been transferred to strains of B. cereus and B. pumilus and may be lost on subculture.
Grows in the presence of lysozyme 0.001%.
Antarctica.
The ability to produce parasporal bodies has been transferred to strains of B. cereus and B. pumilus and may be lost on subculture.
Grows in the presence of lysozyme 0.001%.
- Gordon R.E., Haynes W.C., Pang C.H. (1973) – The genus Bacillus . Agriculture Handbook No. 427, U.S.D.A., Washington D.C.
- Buchanan R.E., Gibbons N.E., Cowan S.T., Holt J.G., Liston J., Murray R.G.E., Niven C.F., Ravin A.W., Stanier R.W. ( 1974) –
Bergey’s Manual of Determinative Bacteriology, Eight Edition, The Williams & Wilkins Company, Baltimore. - Logan N. A., 2005. Bacillus anthracis, Bacillus cereus, and other aerobic endospore-forming bacteria. In: Topley & Wilson’s
Microbiology & Microbial Infections, 10th Edition, Edited by Boriello S.P., Murray P.R., Funke G, Bacteriology, vol. 2, 922-952. - N.A. Logan and P. De Vos, 2009. Genus I. Bacillus Cohn 1872. In: (Eds.) P.D. Vos, G. Garrity, D. Jones, N.R. Krieg, W. Ludwig, F.A.
Rainey, K.-H. Schleifer, W.B. Whitman. Bergey’s Manual of Systematic Bacteriology, Volume 3: The Firmicutes, Springer, 21-127. - Lecadet, M.M., E. Frachon, V. Cosmao, H. Ripouteau, S. Hamon, P. Laurent & I. Thiéry. 1999. Updating the H-antigen classification
of Bacillus thuringiensis. J. Appl. Microbiol. 86: 660-672.
Positive results for lysine decarboxylase, arginine dihydrolase, hydrolysis of esculin,
hydrolysis of casein, hydrolysis of gelatin, tyrosine decomposition, acid production
from: glycerol, starch, N-acetyl-D-glucosamine, arbutin, fructose, maltose, ribose and
trehalose.
Negative results for deamination of phenylalanine, beta-galactosidase, ornithine
decarboxylase, hydrolysis of urea, oxidase, acid production from: methyl beta-
xyloside, adonitol, amygdalin, D- or L-arabitol, dulcitol, erythritol, D- or L-fucose,
galactose, beta-gentiobiose, gluconate, meso-inositol, inulin, 2- or 5-ketogluconate,
lactose, lyxose, melezitose, melibiose, raffinose, rhamnose, sorbitol, sorbose and
xylitol.
Variable results for acidification of salicin, cellobiose and sucrose.
hydrolysis of casein, hydrolysis of gelatin, tyrosine decomposition, acid production
from: glycerol, starch, N-acetyl-D-glucosamine, arbutin, fructose, maltose, ribose and
trehalose.
Negative results for deamination of phenylalanine, beta-galactosidase, ornithine
decarboxylase, hydrolysis of urea, oxidase, acid production from: methyl beta-
xyloside, adonitol, amygdalin, D- or L-arabitol, dulcitol, erythritol, D- or L-fucose,
galactose, beta-gentiobiose, gluconate, meso-inositol, inulin, 2- or 5-ketogluconate,
lactose, lyxose, melezitose, melibiose, raffinose, rhamnose, sorbitol, sorbose and
xylitol.
Variable results for acidification of salicin, cellobiose and sucrose.
(c) Costin Stoica
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