A comparative study of enzyme variation in Bacillus cereus and Bacillus thuringiensis

Abstract

Thirty-two strains of Bacillus spp. were examined in a multilocus enzyme study by agarose gel electrophoresis. The organisms were Bacillus thuringiensis (21 strains, B. cereus (8), including two of var. mycoides, and B. megaterium (3). Strains having similar enzyme variants were grouped into zymovars. A total of 10 of 11 enzyme loci studied were polymorphic and 27 zymovars were distinguished among the 32 strains. The results were subjected to numerical analysis, phenetic affinities and genetic distances between the strains were calculated. The numerical analysis was unable to differentiate between B. thuringiensis and B. cereus. Our results indicated that based on this multilocus enzyme study these zymovars should be considered as belonging to the same species. A mycoides variant of B. cereus was the most distinctive strain studied and clearly belonged to a separate species, B. mycoides. The technique also allowed for identification of contamination and mislabelling of strains.

Use of 16S rRNA, 23S rRNA, and gyrB Gene Sequence Analysis To Determine Phylogenetic Relationships of Bacillus cereus Group Microorganisms

“…1 and 2). These findings resulted in several suggestions to consider B. cereus and B. thuringiensis (8,12,58), or these two bacteria together with B. anthracis (14,21), as one species. Results of our analysis of 16S and 23S rRNA sequences also show disagreement with the current tax- (Tables 2 and 3 and Fig.…”

Characterization of Bacillus thuringiensis and related bacteria by ribosomal RNA gene restriction fragment length polymorphisms

“…This may be a reflection of the narrow catchment area from which the strains were isolated and if we were to examine strain,$ from a wider geographical spread more variation may have been observed. However, the inclusion of thc reference strain suggests that this taxon is homogeneouQ; and this is supported by virtually identical whole-cell protein electrophoresis profiles (Kaji e t al., 1994 (Norris, 1964) and in a small study using multilocus enzyme electrophoresis two strains of serovar israelensis produced identical zymograms and of three strains of serovar kwstaki, two were identical and the third highly related (Zahner et al, 1989). Although most serovars were assigned to individual zymovars, strains of serovars finitimzls, entomocidzas and gallerim produced identical zymogram patterns, suggesting that they belong to the same clone.…”

Distribution of Genes Encoding Putative Virulence Factors and Fragment Length Polymorphisms in the vrrA Gene among Brazilian Isolates of Bacillus cereus and Bacillus thuringiensis

“…Classification into these species is based on pathogenicity (to mammals or insects), plasmid content, and gross morphological characteristics (11,13,34). The genetic similarity between the members of the B. cereus group has been extensively studied by means of various molecular methods, including multilocus enzyme electrophoresis (41), fluorescent amplified fragment length polymorphism analysis (24), and sequence analysis of 16S rRNA, 23S rRNA, gyrB, and a variety of housekeeping genes (6,9,28,32). The data generated by the bulk of these studies indicated that B. cereus and B. thuringiensis are virtually indistinguishable genotypically, which has led a number of researchers to suggest that these taxa may constitute a single species (6,8,9,23).…”