ABSTRACT
ABSTRACT This study investigated the potential of Bacillus thuringiensis isolates obtained in the Cerrado region of the Brazilian state of Maranhão for the biological control of Aedes aegypti larvae. The isolates were obtained from soil samples and the identification of the B. thuringiensis colonies was based on morphological characteristics. Bioassays were run to assess the pathogenicity and toxicity of the different strains of the B. thuringiensis against third-instar larvae of A. aegypti. Protein profiles were obtained by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Polymerase chain reaction assays were used to detect the toxin genes found in the bacterial isolates. Overall, 12 (4.0%) of the 300 isolates obtained from 45 soil samples were found to present larvicidal activity, with the BtMA-104, BtMA-401 and BtMA-560 isolates causing 100% of mortality. The BtMA-401 isolate was the most virulent, with the lowest median lethal concentration (LC50) (0.004 × 107 spores/mL), followed by the Bacillus thuringiensis var. israelensis standard (0.32 × 107 spores/mL). The protein profiles of BtMA-25 and BtMA-401 isolates indicated the presence of molecular mass consistent with the presence of the proteins Cry4Aa, Cry11Aa and Cyt1, similar to the profile of Bacillus thuringiensis var. israelensis IPS-82. Surprisingly, however, none of the cry and cyt genes analyzed were amplified in the isolate BtMA-401. The results of the present study revealed the larvicidal potential of B. thuringiensis isolates found in the soils of the Cerrado region from Maranhão, although further research will be necessary to better elucidate and describe other genes associated with the production of insecticidal toxins in these isolates.
ABSTRACT
Trata-se de um inquérito amostral (743 questionários), realizado nos meses de abril a novembro de 2009 em dez escolas públicas municipais, previamente sorteadas e localizadas em oito bairros da cidade de Caxias. Avaliou-se por meio da aplicação de questionários fechados, o conhecimento dos estudantes sobre a Leishmaniose Visceral (LV), seu vetor e prevenção. Os resultados mostraram mudanças com maior percentual de acertos quanto às respostas sobre a transmissão da doença e quanto aos sintomas da LV no homem e no cão após as campanhas. Contudo, as campanhas educativas são necessárias como medidas para fortalecer a participação da população no combate à LV, pois antes do trabalho educativo a maioria dos estudantes disse que se prevenia da doença evitando contato com cães doentes, entretanto, após as campanhas os mesmos disseram evitar acúmulo de lixo. A pesquisa pode servir como subsídio para orientar novas ações educativas das equipes locais de controle da LV.
This is a sample survey (743 questionnaires) conducted in the months from April to November 2009 in ten pre-selected public schools located in eight districts of the city of Caxias. The students' knowledge of viral leishmaniasis (VL) and its transmission and prevention was evaluated through closed questionnaires. The results showed changes with the highest percentage of correct answers for answers about the transmission of disease and the symptoms of VL in humans and dogs after the campaign. However, educational campaigns are necessary measures to strengthen public participation in combating VL since before the educational work the majority of students stated that the disease was prevented by avoiding contact with sick dogs, however, after the campaign they stated that they avoid accumulations of trash. The research may serve as input to orient further educational actions of local teams for the control of VL.