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Veterinary bacteriology: information about important bacteria
Veterinary bacteriology

Species/Subspecies: Bacillus thuringiensis
Categories: Spore forming; motile
Etymology: Genus name: small rod
Species epithet: named after the German province Thuringia
Significance:Last year year (2009) has about 4000 acres of flooded land, in the Gysinge area at the river Dalälven in Sweden, been sprayed with BTI (see below) to combat the expected mosquito invasion.
  [Of minor importance]   
Type Strain: ATCC 10792 = CCUG 7429
Macromorphology (smell): Form large colonies (2-7 mm in diameter), which are whitish to creamy in colour.
Rods, which usually are motile (1.0-1.2 x 3.0-5.0 µm) and appear single, in pairs or chains. May form spores.
Gram +/Gram -:G+
Metabolism: Facultatively anaerobic
Other Enzymes: Tryptophanase -
Biochemical Tests: Citrate +
Fermentation of carbohydrates:
Other carbohydrates: D-mannose v, D-xylos -.
Spec. Char.:
Reservoir: B. thuringiensis can be isolated from soil. The bacterium also occurs naturally in the gut of caterpillars of of different insects and on plants.
Disease:Schlaffsucht (in German) in flour moth caterpillars (Ephestia kuehniella).
Hosts: Insects, but different serovars have different specificity for different groups of insects (1, butterflies and moths; 2, beetles; 3, flies and mosquitoes; 4, ants, bees, sawflies and wasps).
Clinical Picture:
Virulence Factors: B. thuringiensis forms protein crystals of an insecticidal δ-endotoxins (called crystal proteins or Cry proteins) upon sporulation. These proteins are encoded by the cry genes, which are plasmid borne in most strains of B. thuringiensis. Different Cry toxins are specific against different groups of insects and nematodes. When insects ingest toxin crystals, the toxin is activated at the alkaline pH in their digestive tract, cleavage of the N-terminus and sometimes also the C-terminus. The Cry toxin is then inserted into the cell membranes of the insect gut and forms pores. The pore formation results in cell lysis and eventual death of the insect.
Genome Sequence:
Acc-noStrainSize (bp)Genome
NC_005957 Konkukian 97-27 5 237 682 1c + 1c 

16S rRNA Seq.:
Acc-noStrainNumber of NTOperon
AF290545 ATCC10792T 1482 14 

There are about 250 species described within genus Bacillus. B. thuringiensis is very closely related to B. anthracis and B. cereus, but B. cereus and B. thuringiensis lack the plasmids pX01 and pX02.
Comment:B. thuringiensis serovar israelensis (BTI) produces toxins (Cry toxins) to insects and can be used for biological control of larvae of mosquitoes. The serovars Kurstaki (see Fig. 187:1) and Aizawai are used to combat caterpillars of the tomatoe moth (Lacanobia oleracea) and the cabbage butterfly (Pieris brassicae).

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