Imidacloprid Induced Intoxication and its Biodegradation by Soil Isolate Bacillus weihenstephanensis.

Aims: Study was carried out to investigate the effect of imidacloprid on biochemical parameters and growth of soil isolate. The imidacloprid degradation by the soil isolate was also studied. Study Design: The soil isolate was identified and used for toxicity testing. The isolate of Bacillus weihenstephanensis was further tested for its ability to degrade imidacloprid in minimal salt medium (MSM) and tryptic soya medium (TSB). The role of plasmid in imidacloprid degradation was established by curing experiments. Place and Duration of Study: Department of Biotechnology and Microbiology, Karnatak University, Dharwad, India between June 2011 and December 2012. Methodology: The soil isolate was identified by morphological, biochemical characters and 16s rDNA identification. Effect of imidacloprid on DNA, RNA, protein, glucose and growth in soil isolate was studied with 10-3 to 10-7 molar imidacloprid for 96 h. Imidacloprid degradation was determined in MSM and TSB for 28 days with samples taken on 7, 14, 21 and 28th day. The insecticide concentration was tested by HPLC. Plasmid curing was performed. Results: The soil isolate was identified as Bacillus weihenstephanensis. The study involving soil isolate Bacillus weihenstephanensis with 10-3 to 10-7 molar imidacloprid showed significant (P<0.05) decrease in content of DNA, RNA, protein, glucose and growth. Bacillus weihenstephanensis in MSM and TSB showed 46 and 78 % imidacloprid degradation in four weeks. The plasmid of Bacillus weihenstephanensis was cured in fourth generation. 18.80% and 75% degradation observed in cured and non cure cells of Bacillus weihenstephanensis in TSB. Conclusion: Study showed that imidacloprid affects the biochemical contents and intern growth of soil isolate Bacillus weihenstephanensis. Study also revealed that Bacillus weihenstephanensis was able to degrade imidacloprid in MSM and TSB. Further plasmid curing revealed that the genes for imidacloprid degradation are located both in plasmid and chromosome.

Antihelmintic activity of stem bark extract of bridelia retusa spreng.

The present study was undertaken to investigate antichelmintic activity of petroleum ether, chloroform, ethanol and aqueous extract of the stem bark of Bridelia retusa S. on adult African night crawlers (Eudrilus euginae) earthworms due to its anatomical and physiological similarity with the intestinal roundworm parasites of human being. Antihelmintic activity was investigated at 50 mg/ml for all the four extracts on earthworms and compared with standard piperazine citrate. The time of paralysis and death of the earthworms for piperazine citrate, petroleum ether, chloroform, ethanol and aqueous extract was noted. The death of earthworms occurred within few minutes of their paralysis. However, in control group, worms were observed for 24 hours and no paralysis or death was found during that period. In the present study, the extracts obtained using polar and non polar solvents were used for antihelmintic activity against earthworms. Comparing all extracts and standard of piperazine citrate at the same concentration (50 mg/ml), it was clear that chloroform extract showed significantly (p<0.05) better effect and hence higher antihelmintic activity in comparison to petroleum ether, ethanol and aqueous extract as well as that of standard, followed by ethanol extract which showed similar effects to standard while the rest of the extract showed poor effects. Thus indicating antihelmintic properties of the extract which may be attributed to the phytoconstituents present in it which needs further investigation.

Effect of dexamethasone on implantation and pregnancy in albino rats.

Administration of 3 mg/kg body weight of dexamethasone from day 1 or 3 to 7 of pregnancy did not prevent implantation in albino rats. But the same dose when administered from day 8 to 11 resulted in complete abortion / resorption in all rats. Administration of 2 mg / kg body weight of dexamethasone from day 8 to 11 of pregnancy held no effect on the foetal survival. The results indicate that a high dose of dexamethasone does not affect implantation but the same dose affects the more advanced stages of pregnancy.

Effect of methyl parathion formulation on estrous cycle and reproductive performance in albino rats.

The animals were injected intraperitoneally with graded doses of methyl parathion at 1.5 to 3 mg/kg body weight for 15 days from the day of estrus. Results indicated that the methyl parathion treatment showed irregular estrous cycles, affect the duration of each estrous cycle, proestrus and diestrus were significantly changed in 2.5 and 3 mg treatment groups. But there was no significant change in the number and duration of each estrous cycle, duration of proestrus and diestrus in 1.5 and 2 mg methyl parathion treatment groups. However, there was a significant decrease in the duration of estrus, while there was no significant change in the duration of metestrus in all methyl parathion treatment rats when compared with those of the corresponding parameters of the control. There was no significant effect on number of live pups on day 1 and 5 except in 3 mg methyl parathion treatment group where it was significantly decreased. There was no significant change in reproductive indices like pregnancy, parturition, live birth and viability in all the methyl parathion treatment rats except the viability index in the highest dose.

Effect of edifenphos on follicular dynamics in albino rats.

Exposure of rats to 0.1, 0.15 and 0.20 mg/100 g body weight edifenphos (i.p.) had no significant effect on the number of healthy follicles and atretic follicles in all the stages. However, treatment with 0.25 mg dose resulted in a significant decrease in stage I and total number of healthy follicles and increase in stage V atretic follicles. A significant decrease in stage I, II, III and total number of healthy follicles, and a significant increase in stage I, III, IV and total number of atretic follicles were observed in 0.3 mg edifenphos treated rats. The results indicate that the effect of edifenphos is dose dependent.