Project description:Lantibiotics are ribosomally synthesized antimicrobial peptides with substantial posttranslational modifications. They are characterized by the unique amino acids lanthionine and methyllanthionine, which are introduced by dehydration of Ser/Thr residues and linkage of the resulting dehydrated amino acids with Cys residues. BLAST searches using the mersacidin biosynthetic enzyme (MrsM) in the NCBI database revealed a new class II lantibiotic gene cluster in Bacillus pseudomycoides DSM 12442. Production of an antimicrobial substance with activity against Gram-positive bacteria was detectable in a cell wash extract of this strain. The substance was partially purified, and mass spectrometric analysis predicted a peptide of 2,786 Da in the active fraction. In order to characterize the putative lantibiotic further, heterologous expression of the predicted biosynthetic genes was performed in Escherichia coli. Coexpression of the prepeptide (PseA) along with the corresponding modification enzyme (PseM) resulted in the production of a modified peptide with the corresponding mass, carrying four out of eight possible dehydrations and supporting the presence of four thioether and one disulfide bridge. After the proteolytic removal of the leader, the core peptide exhibited antimicrobial activity. In conclusion, pseudomycoicidin is a novel lantibiotic with antimicrobial activity that was heterologously produced in E. coli.
Project description:In general, the endosphere isolate EC18 showed more numbers of genes significantly altered in the presence of root exudates than the soil isolate SB8 . Some of the altered genes in the two strains showed overlap. Some of these genes were previously reported to be involved in microbe-plant interactions, such as organic substance metabolism, oxidation reduction, transmembrane transportation and a subset with putative or unknown function. It was also found some genes showed opposite trend among the two strains.
Project description:The plant growth-boosting biofilm-forming bacteria Bacillus pseudomycoides is able to promote growth and drought stress tolerance in wheat by suppressing the MYB gene, which synthesizes Myb protein (TaMpc1-D4) through secreted volatile compounds. In the present study, Triticum aestivum seeds were inoculated with five distinct bacterial strains. The growth, germination rate, root-shoot length, RWC, and chlorophyll content of seedlings were investigated. Furthermore, the levels of soluble sugars, proteins, H2O2, NO, cell death, and antioxidant enzymes (CAT, SOD, POD, and APX) were observed throughout the growth stage. All of the results showed that B. pseudomycoides had a substantially higher ability to form biofilm and promote these traits than the other strains. In terms of molecular gene expression, B. pseudomycoides inoculation strongly expressed the Dreb1 gene by silencing the expression of MYB gene through secreted volatile compounds. For identifying the specific volatile compound that silenced the MYB gene, molecular docking with Myb protein was performed. Out of 45 volatile compounds found, 2,6-ditert-butylcyclohexa-2,5-diene-1,4-dione and 3,5-ditert-butylphenol had a binding free energy of - 6.2 and - 6.5, Kcal/mol, respectively, which predicted that these compounds could suppress this protein's expression. In molecular dynamics simulations, the RMSD, SASA, Rg, RMSF, and hydrogen bonding values found assured the docked complexes' binding stability. These findings suggest that these targeted compounds may be suppressing Myb protein expression as well as the expression of Dreb1 and other drought response genes in wheat. More research (field trial) into plant growth and drought stress is needed to support the findings of this study.
Project description:[1] Transcription profiling of one Burkholderia cenocepacia clinical isolate, J2315, versus a soil isolate, HI2424, in conditions mimicking CF sputum [2] Transcription profiling of Burkholderia cenocepacia isolates J2315 and HI2424 in media mimicking CF sputum or the soil environment
Project description:The aim of the study was to carry out a CGH study utilizing a set of 39 diverse Bacillus isolates. Thirty four B. cereus and five B. anthracis strains and isolates were chosen so as to represent different lineages based on previous characterizations, including MLEE and MLST (Helgason, Okstad et al. 2000; Helgason, Tourasse et al. 2004). They represent the spectrum of B. cereus phenotypic diversity by including soil, dairy and periodontal isolates in addition to virulent B. anthracis strains.