Sindhu, S.S.Dua, Seema2017-06-032017-06-032014http://krishikosh.egranth.ac.in/handle/1/5810014528Selected ten bacterial strains having termite killing ability along with two control strains was studied for antagonistic interactions with local soil termites. Live bacterial cells, heat killed cells and culture supernatants were tested for termiticidal activity. Different bacterial strains showed more than 80% killing of termites at 5 days of incubation. Four bacterial strains KBM79, KPM35, PPM147 and PBM195 caused 100% killing at 10 days of observation. The cell free culture filtrate studies of these antagonistic cultures showed that antagonistic substance is extracellular. Termite mortality percentage increased when culture supernatants were used as compared to whole cell broth of bacterial strains. The killing frequency of the culture supernatants obtained from different bacterial strains varied from 78.0 to 96.0% at 2nd day of observation. Termicidal activity was lost on treatment of whole cell broth and culture supernatant of bacterial strains by incubation at high temperature (1000C for 10 minutes). Bacterial strains KBM79 and KPM35 possessed proteolytic, lipolytic and chitinolytic enzyme activities and caused 100% killing of termites at 10 days. Partial purified proteins caused 100% killing of termites within half an hour. The SDS–PAGE analysis of selected bacterial strains showed four common protein/polypeptides having molecular weight 129 KDa, 37.1 KDa, 28.7 KDa and 26.3 KDa in all the ten bacterial strains. These proteins/polypeptides were missing in control bacterial strains WPS73 and KPM31. Plasmid-cured strain KPM35 lost the protein band having molecular weight 129 KDa. Termiticidal activity was also decreased in plasmid-cured strain KPM35 indicating that some of the termiticidal genes were located on the plasmid. Moreover, crude preparation and partial purified protein of bacterial strains KBM79 and KPM35 when treated with proteinase K lost the antagonistic activity indicating that extracellular protein could be involved in termite mortality. Combination of different chemical compounds with efficient bacterial strains showed high termite mortality than individual insecticides. Application of bacterial strain KPM35 and dexamethasone (50 ug/ml) caused 100% mortality even at 12 hours of incubation. Dexamethasone alone was found more lethal than boric acid and sodium citrate, and caused 90% mortality at 48 hours of incubation. Bacterial strains KBM79 and KPM35 were identified as Bacillus subtilis and Pseudomonas synxantha. These bacterial strains could be further tested for termiticidal activity under field conditions.enbiological phenomena, bacteria, proteins, enzymes, insecticides, productivity, poultry equipment, fungi, plasmids, selectionThesis