Autor(es): Hire, Ramesh S.; Hadapad, Ashok B.; Vijayalakshmi, Narayanan; Dongre, Tanaji K.

Resumo: Three indigenous isolates of Bacillus sphaericus (ISPC-5, ISPC-6 and ISPC-8), along with standard 2362 and 1593 strains, were evaluated for spore viability and mosquitocidal activity. Among these, ISPC-8 was the most viable and virulent isolate, exhibiting a significantly higher total viability count (TVC) and lower LC50 values. The TVC of the standard strains ranged from 4.0 to 9.2 x 108 spores mL-1, whereas it was 1.3 x 109 spores mL-1 for ISPC-8. The LC50 values of ISPC-8, 2362 and 1593 against Culex quinquefasciatus were 0.68 x 103, 1.22 x 103 and 1.85 x 103 spores mL-1, respectively. The ISPC-8 was further assessed for host spectrum and found to be more active against C. quinquefasciatus, followed by Culex tritaeniorhynchus, Aedes albopictus and Aedes aegypti. The ISPC-8 strain was thus found to be a promising isolate for developing biopesticides. Among the indigenous strains, only ISPC-8 was found to have binary toxin genes (binA and binB). Comparative sequence analysis revealed that the BinA (41.9 kDa) protein of ISPC-8 differs by one amino acid (R197M), whereas BinB (51.4 kDa) differs by two amino acids (H99P, P174S) as compared with 1593 and 2362 strains. The purified binary proteins of ISPC-8 showed an LC50 value of 6.32 ng mL-1 against C. quinquefasciatus larvae after 48 h.

Palavras-Chave: Toxicants; Microbiology; Pest control; Spores; Toxicity tests; Aquatic insects; Mortality causes; Public health; Toxins; Amino acid sequence; Pesticides; Larvae; Proteins; Culex quinquefasciatus; Aedes aegypti; Culex tritaeniorhynchus; Bacillus sphaericus; Aedes albopictus

Imprenta: Microbiology Letters, v. 305, n. 2, p. 155-161, 2010.

Descritores: Aedes aegypti - Proteins ; Aedes aegypti - Public health

Data de publicação: 2010