Project description:Paenibacillus polymyxa is an agriculturally important plant growth promoting rhizobacterium (PGPR). Many Paenibacillus species are known to be engaged in complex bacteria-bacteria and bacteria-host interactions, which in other bacteria were shown to necessitate quorum sensing communication, but to date no quorum sensing systems have been described in Paenibacillus. Here we show that the type strain P. polymyxa ATCC 842 encodes at least 16 peptide-based communication systems. Each of these systems comprises a pro-peptide that is secreted to the growth medium and further processed to generate a mature short peptide. Each peptide has a cognate intracellular receptor of the RRNPP family, and we show that external addition of P. polymyxa communication peptides to the medium leads to reprogramming of the transcriptional response. We found that these quorum sensing systems are conserved across hundreds of species belonging to the Paenibacillaceae family, with some species encoding more than 25 different peptide-receptor pairs, representing a record number of quorum sensing systems encoded in a single genome.
Project description:Tellurium (Te) is a metalloid that is growing as a challenge since its increasing environmental presence, as a result of mining activity and improper disposal of high-tech devices, leads to an increasing selective pressure against living organisms. How microorganims adapt to the presence of increasing concentrations of metalloids, such as Te, could increase the know-how to solve Te contamination problems. Two mining isolates, Bacillus sp. and Paenibacillus sp, were able to grow in high concentrations of Te(IV) and were able to reduce Te(IV) to Te(0) so the effects of growth in the presence of Te(IV) was determined, at the level of total protein expression, for this strains. It was determined that growth of these strains in the presence of Te(IV) affected the general protein expression pattern, and hence the metabolism.
Project description:The alkaliphilic halotolerant bacterium Bacillus sp. N16-5 often faces salt stress in its natural habitats. One-color microarrays was used to investigate transcriptome expression profiles of Bacillus sp. N16-5 adaptation reactions to prolonged grown at different salinities (0%, 2%, 8% and 15% NaCl) and the initial reaction to suddenly alter salinity from 0% to 8% NaCl.
