Larvicidal toxicity of Japanese Bacillus thuringiensis against the mosquito Anopheles stephensi |
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Authors: | HIROYUKI SAITOH KAZUHIKO HIGUCHI EIICHI MIZUKI & MICHIO OHBA |
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Institution: | Fukuoka Industrial Technology Centre, Kurume, Fukuoka, japan,;Institute of Biological Control, Kyushu University, Fukuoka, Japan |
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Abstract: | Japanese isolates of Bacillus thuringiensis were screened for larvicidal activity against the mosquito Anopheles stephensi , the urban malaria vector of the Indian subcontinent. Among more than 30 strains identified, larvicidal activity causing >80% mortality in 72 h was demonstrated for 41/1449 (2.8%) isolates. The majority of strains and isolates (97.2%) exhibited little or no larvicidal activity. Anopheles -active strains belonged to more than 12 H serotypes, especially H3ade (serovar fukuokaensis ) and H44 (serovar higo ). SDS-PAGE profiles of inclusion proteins showed 4 distinct types among 6 active strains examined. The most active Japanese isolates were H20 strain 89-T-34-14 (LC50 4.4 μg/ml) and H44 serovar higo strain 74-E-45-24 (LC50 7.6 μg/ml), respectively, 13-fold and 23-fold less active than the international standard H14 serovar israelensis (LC50 0.33 μg/ml). |
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