Sequencing and Characterization of pBM400 from Bacillus megaterium QM B1551

Abstract

Bacillus megaterium QM B1551 plasmid pBM400, one of seven indigenous plasmids, has been labeled with a selectable marker, isolated, completely sequenced, and partially characterized. A sequence of 53,903 bp was generated, revealing a total of 50 predicted open reading frames (ORFs); 33 were carried on one strand and 17 were carried on the other. These ORFs comprised 57% of the pBM400 sequence. Besides the replicon region and a complete rRNA operon that have previously been described, several interesting genes were found, including genes for predicted proteins for cell division (FtsZ and FtsK), DNA-RNA interaction (FtsK, Int/Rec, and reverse transcriptase), germination (CwlJ), styrene degradation (StyA), and heavy metal resistance (Cu-Cd export and ATPase). Three of the ORF products had high similarities to proteins from the Bacillus anthracis virulence plasmid pXO1. An insertion element with similarity to the IS256 family and several hypothetical proteins similar to those from the chromosomes of other Bacillus and Lactococcus species were present. This study provides a basis for isolation and sequencing of other high-molecular-weight plasmids from QM B1551 and for understanding the role of megaplasmids in gram-positive bacteria. The genes carried by pBM400 suggest a possible role of this plasmid in the survival of B. megaterium in hostile environments with heavy metals or styrene and also suggest that there has been an exchange of genes within the gram-positive bacteria, including pathogens.

Molecular Characterization of Plasmid pBM300 from Bacillus megaterium QM B1551

“…Such hydrolases are important in germination. In fact, a CwlJ gene has also been found on pBM400 in QM B1551 (38). The plasmid-borne hydrolase genes may help explain the efficient, synchronized germination of this species observed by many laboratories.…”

Bacillus megaterium—from simple soil bacterium to industrial protein production host

“…Hence, the theta replicons appear to be unique. The two 20 rolling circle plasmids (5.4 and 9.1 kb) are not similar to each other, but their replicons show similarities to sequences of plasmids known from Bacillus thuringiensis and B. anthracis (Scholle et al 2003). In QM B1551, the plasmids are very stable and several have been followed through 100 generations with no selection or loss.…”

“…Furthermore, genes encoding proteins for heavy metal export, many 10 possible transport proteins, acyl carriers, sigma factors, and sterols were found. Redox, mobilization, and transfer genes, as well as sporulation and germination genes were identified (Kunnimalaiyaan et al 2001;Kunnimalaiyaan and Vary 2002;Scholle et al 2003). Moreover, there are genes very similar to some found on the virulence plasmids of Bacillus anthracis and at least one complete rRNA operon with 18 tRNA genes (Kunnimalaiyaan et al 2001).…”

TraA is required for megaplasmid conjugation in Rhodococcus erythropolis AN12

“…Though megaplasmids are common within this genus of actinomycetes, this type of extrachromosomal replicon is not exclusive to rhodococci. Large plasmids (>50 kb) have been found in Gram-negative bacteria (Argandona et al, 2003;Pedraza and Diaz Ricci, 2002) and other types of Gram-positive bacteria (Kinashi et al, 1987;Scholle et al, 2003).…”