Isolation of Antibiotic Producing Bacteria from Soil.

Most antibiotics used today are isolated and extracted from microbial source. The emergence of antibiotic resistance and need for better, broad spectrum antibiotics is always in high demand. In the present study, antibiotic producing bacteria were isolated from a local soil sample. After primary screening, two bacterial strains (strain 1 and 2) were isolated, which showed antimicrobial activity against some common bacteria namely, E. coli, K. pneumonia, S. aureus, P.aeruginosa and M. smegmatis. The isolated strains showed prominent zones of inhibition against E. coli, K. pneumoniae, S. aureus and P. Aeruginosa but not against M. smegmatis. To identify the isolated strains, biochemical tests were performed and it was found that both the strains were Bacillus sp with some differences in cultural characteristics. The strains were also found to be resistant to some antibiotics such as tetracycline. The screen for the presence of any plasmid which might be influencing antibiotic production by these strains, the cultures were used for extraction of plasmids wherein, both the strains were observed to have a plasmid of ~ 10 kb. Further study in identification of these strains will be helpful in improving these strains for antibiotic production.

Profilin activates bacillus thuringiensis phosphoinositide specific phospholipase C.

Many extracellular signaling molecules including hormones, growth factors, neurotransmitters and immunoglobulins elicit intracellular responses by activating phosphatidylinositol-specific phospholipase C (PI-PLC) upon binding to their cell surface receptors. Activated PLC catalyses the hydrolysis of Phosphotidylinositol 4,5- bisphosphate (PIP2) to generate DAG and IP3 , which act as signaling molecules that control various cellular processes. Exploring the mechanism of regulation of PLC activity may lead to understanding various signaling events that regulate cell growth and differentiation. One of the dramatic effects of profilin is inhibition of PIP2 hydrolysis by PLC- γ in eukaryotic cells. In the present study, the effect of profilin on Phosphotidylinositol specific phospholipase C (PIPLC) purified from Bacillus thuringiensis (Bt) was examined. Assay of PI-PLC activity indicated that Bovine profilin activated the hydrolysis of phosphotidylinositol (PI) by BtPI-PLC in a concentration dependent manner under in vitro conditions. A 250 % increase in activity was noted in the presence of profilin but not in presence of phosphoprofilin. In the presence of profilin more proteins are observed in the soluble fraction. In conclusion it can be stated that that profilin activates bacterial PLC activity towards PI hydrolysis.