( 2009 )
Discovery of marine Bacillus species by 16S rRNA and rpoB comparisons and their usefulness for species identification.
PMID : 19166882 : DOI : 10.1016/j.mimet.2009.01.003
Systematic studies of the Bacillus group have been biased towards terrestrial and pathogenic isolates, and relatively few studies have examined Bacillus species from marine environments. Here we took twenty Bacillus strains from diverse marine environments and sequenced their 16S rRNA. Using molecular comparisons, we separated the strains into thirteen Bacillus genotypes and identified 9 species: B. aquaemaris. B. badius, B. cereus group, B. firmus, B. halmapalus, B. hwajinpoensis, B. litoralis, B. sporothermodurans, B. vietnamensis, and three indistinguishable Bacilli. In addition, we sequenced the DNA-directed RNA polymerase beta subunit (rpoB) gene and assessed its discriminative power in identifying Bacilli. Phylogenetic trees of Bacillus rpoB genes separated each Bacillus according to their taxonomic positions and were supported statistically. The resolution of Bacillus on the rpoB phylogenetic tree was approximately 4.5 times greater than on the 16S rRNA phylogenetic tree. These results demonstrate that the polymorphism of the Bacillus rpoB gene can be used to identify Bacillus species, providing an improved identification scheme for Bacillus species.
( 2013 )
Raw starch-degrading �\-amylase from Bacillus aquimaris MKSC 6.2: isolation and expression of the gene, bioinformatics and biochemical characterization of the recombinant enzyme.
PMID : 23020612 : DOI : 10.1111/jam.12025
The aims were to isolate a raw starch-degrading �\-amylase gene baqA from Bacillus aquimaris MKSC 6.2, and to characterize the gene product through in silico study and its expression in Escherichia coli. A 1539 complete open reading frame of a starch-degrading �\-amylase gene baqA from B. aquimaris MKSC 6�P2 has been determined by employing PCR and inverse PCR techniques. Bioinformatics analysis revealed that B. aquimaris MKSC 6.2 �\-amylase (BaqA) has no starch-binding domain, and together with a few putative �\-amylases from bacilli may establish a novel GH13 subfamily most closely related to GH13_1. Two consecutive tryptophans (Trp201 and Trp202, BaqA numbering) were identified as a sequence fingerprint of this novel GH13 subfamily. Escherichia coli cells produced the recombinant BaqA protein as inclusion bodies. The refolded recombinant BaqA protein degraded raw cassava and corn starches, but exhibited no activity with soluble starch. A novel raw starch-degrading B. aquimaris MKSC 6.2 �\-amylase BaqA is proposed to be a member of new GH13 subfamily. This study has contributed to the overall knowledge and understanding of amylolytic enzymes that are able to bind and digest raw starch directly.