EVALUATION OF CONVENTIONAL LABORATORY MEDIA FOR PRODUCING ACTIVELY TOXIC STRAINS OF Bacillus sphaericus | ||
| Journal of Agricultural Chemistry and Biotechnology | ||
| Article 1, Volume 34, Issue 1, January 2009, Pages 1-18 PDF (519.21 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jacb.2009.90246 | ||
| Authors | ||
| Ferial M. Rashad; W. D. Saleh; Hayam M. Fathy | ||
| Dept. of Microbiology, Fac., of Agric., Cairo Univeristy | ||
| Abstract | ||
| Two actively marked toxic strains of Bacillus sphaericus NSE1 and NSE2, previously isolated from the soil of North Sinai in Egypt, identified morphologically, biochemically and assayed biologically against mosquito larvae, were used in the present study along with the reference strains of Bacillus sphaericus 1593 and 2297. The PCR product profiles indicated the presence of genes encoding Bin A, Bin B and Mtx1 in all analyzed strains; they are consistent with protein profiles. PM achieved the highest significant yield during the first 72 hr of fermentation course, but after 120 hr NYSM attained the highest significant yield of 1.1 - 1.3 × 109 CFU/ml and stand with PM without significant differences. AYEM, LBM and GGSEM, in that order, came after. The maximum yield of spores was reached at the end of the fermentation time in both PM and NYSM followed by GGSEM. However, the highest significant sporulation rate (88.5 - 100%) was obtained in NYSM followed by PM and GGSEM (71.4 – 93.3%), (40.0 – 80%), respectively. The synthesis of protein was observed only from 6 hr (NSE1, 2297), 9 hr (1593) and 12 hr (NSE2) onwards and reached the maximum level after 120 hr. The significant highest quantities was attained in PM. Local strains, NSE1 and NSE2, respectively, always produced significantly higher protein amounts in fermentation media than the standard strains 2297and 1593. The maximum toxicity against 3rd instar of Culex pipiens (LC50 5 x 103 and 8 x 103 CFU/ml) was noticed with local strains NSE1 and NSE2, respectively in PM by 5 days without significant differences. In all of the fermentation runs, changes in pH showed a similar pattern, rising to reach about 8.3 - 9.0 at the end of fermentation. | ||
| Keywords | ||
| Bacillus sphaericus; Culex pipiens; Larvicide; Conventional media | ||
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