RESUMO
Mosquitocidal bacteria are environmentally friendly alternatives to chemical insecticides for controlling mosquitoes and therefore, there have been tremendous world-wide efforts to identify novel mosquitocidal bacteria from natural environment. In the present study, excreta from arid-birds were analyzed for identifying mosquitocidal bacteria. The selection of sample for bacterial screening is significant, because, arid-birds are the unique living species and gathering the foods from variety of sources from environment. Out of 1000 samples examined, twelve bacterial strains were identified as mosquitocidal and the 16S rRNA gene sequence alignment depicted that these isolates belonged to Bacillus species (Bacillus thuringiensis, B.sphaericus and B.cereus). Toxicity assay against mosquito vectors have shown that these isolates are potential. The B. sphaericus VCRC-B547 (NCBI: JN377789) has shown a higher toxicity against Cx. quinquefasciatus, An. stephensi, and Aed. aegypti. Result from SDS-PAGE has shown that there was considerable difference in the protein profiles among the new bacterial isolates. Phylogenetic tree with branch length 0.05 revealed three distinct groups with homology among the closely related Bacillus strains. This study therefore throws considerable interest on the diversity of microbial organisms from arid birds and its application in mosquito control.
Assuntos
Animais , Bacillus/classificação , Bacillus/genética , Bacillus/isolamento & purificação , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/toxicidade , Aves/parasitologia , Culicidae/efeitos dos fármacos , Culicidae/parasitologia , DNA Bacteriano/genética , Eletroforese em Gel de Poliacrilamida , Fezes/parasitologia , Larva/parasitologia , Controle de Mosquitos/métodos , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genéticaRESUMO
Optimization of chicken feather (CF) based culture medium for the production of Bacillus thuringiensis subsp. israelensis (Bti) biomass in combination with the agro industrial by-product (coconut cake, CC) and manganese chloride (MnCl2) has been evaluated. The biomass yield of Bti spore/crystal toxin was highest (12.06 g/L) from the test medium (CF+CC+MnCl2) compared to the reference medium (Luria Bertani, LB). Toxicity assay with Bti produced from the test medium against mosquito vectors (Culex quinquefasciatus, Anopheles stephensi and Aedes aegypti) was also satisfactory and results were comparable with bacteria produced from LB. The results suggest that Bti can be produced to the maximum extent possible as a potential mosquitocidal activity as suggested by the test medium (CF+CC+MnCl2).
RESUMO
Knowledge on infectious diseases encompasses a vast and constantly changing arena; and consistent research work is imperative to understand and combat the new problems resulting from emerging infectious diseases. Public health workers and epidemiologists aim at lowering morbidity and mortality due to diseases by preventing infections. For the rapidly expanding majority of the world's population; who live in the largely tropical areas of Africa; Asia and Latin America; the greatest threats to health remain tropical infectious diseases. Emerging infectious diseases are new; emerging or drug-resistant infections; whose incidence in humans may increase in the near future. With rapidly increasing international travel; the globalization and industrialization of food supply and exploding populations; infectious diseases pose unprecedented threats around the globe. Thus the imperative need is to promptly recognize; isolate and appropriately manage tropical infectious diseases. This review paper has attempted to provide the much needed insight into the different aspects of the major tropical infectious diseases affecting humans throughout the world