yneA mRNA instability is involved in temporary inhibition of cell division during the SOS response of Bacillus megaterium.

The SOS response, a mechanism enabling bacteria to cope with DNA damage, is strictly regulated by the two major players, RecA and LexA (Bacillus homologue DinR). Genetic stress provokes formation of ssDNA-RecA nucleoprotein filaments, the coprotease activity of which mediates the autocatalytic cleavage of the transcriptional repressor DinR and ensures the expression of a set of din (damage-inducible) genes, which encode proteins that enhance repair capacity, accelerate mutagenesis rate and cause inhibition of cell division (ICD). In Bacillus subtilis, the transcriptional activation of the yneAB-ynzC operon is part of the SOS response, with YneA being responsible for the ICD.

Comparative evaluation of establishing a human gut microbial community within rodent models.

The structure of the human gut microbial community is determined by host genetics and environmental factors, where alterations in its structure have been associated with the onset of different diseases. Establishing a defined human gut microbial community within inbred rodent models provides a means to study microbial-related pathologies, however, an in-depth comparison of the established human gut microbiota in the different models is lacking. We compared the efficiency of establishing the bacterial component of a defined human microbial community within germ-free (GF) rats, GF mice, and antibiotic-treated specific pathogen-free mice.

Gordonibacter pamelaeae gen. nov., sp. nov., a new member of the Coriobacteriaceae isolated from a patient with Crohn's disease, and reclassification of Eggerthella hongkongensis Lau et al. 2006 as Paraeggerthella hongkongensis gen. nov., comb. nov.

A strictly anaerobic, Gram-positive, short-rod/coccobacillus-shaped bacterial strain, designated 7-10-1-b(T), was isolated from the colon of a patient suffering from acute Crohn's disease. The isolate formed small, pale-white, semi-translucent colonies on solid cultivation media. The strain was catalase-positive and metabolized only a small number of carbon sources.

Targeted deletion of the uvrBA operon and biological containment in the industrially important Bacillus licheniformis.

From a Bacillus licheniformis wild type as well as a defined asporogenous derivative, stable UV hypersensitive mutants were generated by targeted deletion of the uvrBA operon, encoding highly conserved key components of the nucleotide excision repair. Comparative studies, which included the respective parental strains, revealed no negative side effects of the deletion, neither on enzyme secretion nor on vegetative propagation. Thus, the uvrBA locus proved to be a useful deletion target for achieving biological containment in this industrially exploited bacterium.

Coexpression of the type I signal peptidase gene sipM increases recombinant protein production and export in Bacillus megaterium MS941.

The removal of the signal peptide from a precursor protein is a crucial step of protein secretion. In order to improve Bacillus megaterium as protein production and secretion host, the influence of homologous type I signal peptidase SipM overproduction on recombinant Leuconostoc mesenteroides dextransucrase DsrS synthesis and export was investigated. The dsrS gene was integrated as a single copy into the chromosomal bgaM locus encoding beta-galactosidase.

Strain development in Bacillus licheniformis: construction of biologically contained mutants deficient in sporulation and DNA repair.

By introducing defined deletions in recA and an essential sporulation gene (spoIV), stable mutant strains of Bacillus licheniformis were obtained which are totally asporogenous and severely affected in DNA repair, and thus being UV-hypersensitive. Studies on growth in various liquid media as well as on amylase production revealed no differences of the mutants when compared to the wild type. Hence, such genes appear to be suitable disruption targets for achieving passive biological containment in this industrially exploited species.

Test systems to study transcriptional regulation and promoter activity in Bacillus megaterium.

Plasmid-located (multi-copy) and chromosomally located (single-copy) promoter test systems were developed for Bacillus megaterium by making use of the homologous beta-galactosidase-encoding bgaM gene. The multi-copy system facilitates rapid promoter analyses and promoter trapping, whereas the single-copy system, integrated into the chromosome, allows investigation of tightly regulated promoters. As a prerequisite for both the multi- and the single-copy systems, a beta-galactosidase-deficient B.

Evidence for two recA genes mediating DNA repair in Bacillus megaterium.

Isolation and subsequent knockout of a recA-homologous gene in Bacillus megaterium DSM 319 resulted in a mutant displaying increased sensitivity to mitomycin C. However, this mutant did not exhibit UV hypersensitivity, a finding which eventually led to identification of a second functional recA gene. Evidence for recA duplicates was also obtained for two other B.

The Bacillus megaterium comE locus encodes a functional DNA uptake protein.

From Bacillus megaterium, a genomic region was isolated and structurally characterized which strongly resembles the Bacillus subtilis competence locus comE encoding proteins involved in DNA uptake. Functionality of the B. megaterium comEA gene was proven by complementing a DNA-receptor mutant of B.