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A Bacitracin-Resistant Bacillus subtilis Gene Encodes a Homologue of the Membrane-Spanning Subunit of the Bacillus licheniformis ABC Transporter. Reiko Ohki, 2003.Bacitracin is a peptide antibiotic nonribosomally produced by Bacillus licheniformis . The bcrABC genes which confer bacitracin resistance to the bacitracin producer encode ATP binding cassette (ABC) transporter proteins, which are hypothesized to pump out bacitracin from the cells . Bacillus subtilis 168, which has no bacitracin synthesizing operon, has several genes homologous to bcrABC . It was found that the disruption of ywoA, a gene homologous to bcrC, resulted in hypersensitivity to bacitracin . Resistance to other drugs such as surfactin, iturin A, vancomycin, tunicamycin, gramicidin D, valinomycin and several cationic dyes were not changed in the ywoA disruptant . Spontaneous bacitracin-resistant mutants (Bcr-1 and -2) isolated in the presence of bacitracin have a single base substitution from A to G in the ribosome binding region . Northern hybridization analysis and determination of the expression of ywoA-LacZ transcriptional fusion gene revealed that the transcription of the ywoA gene was dependent on extracytoplasmic function (ECF)  factors
M and
X . Preincubation of wild-type cells in the presence of a low concentration of bacitracin induced increased resistance to bacitracin about two- to threefold, although the mechanism of this induction has not yet been elucidated . It has been reported that a commercially available bacitracin is a mixture of several components and also contains impurity . Bacitracin A was purified by reverse phase high-performance liquid chromatography (HPLC) . Similar results were obtained with bacitracin A as those with crude bacitracin, indicating that contaminating substances were not responsible for the results obtained in this study .
Genome-Wide Analysis of Lipoprotein Expression in Escherichia coli MG1655. Stephen J. Brokx, 2004.To gain insight into the cell envelope of Escherichia coli grown under aerobic and anaerobic conditions, lipoproteins were examined by using functional genomics . The mRNA expression levels of each of these genes under three growth conditions—aerobic, anaerobic, and anaerobic with nitrate—were examined by using both Affymetrix GeneChip E . coli antisense genome arrays and real-time PCR (RT-PCR) . Many genes showed significant changes in expression level . The RT-PCR results were in very good agreement with the microarray data . The results of this study represent the first insights into the possible roles of unknown lipoprotein genes and broaden our understanding of the composition of the cell envelope under different environmental conditions . Additionally, these data serve as a test set for the refinement of high-throughput bioinformatic and global gene expression methods .
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