ABSTRACT
Chrysomya albiceps (Wiedemann) is an important vector of animal and diseases as well as causer of secondary myiasis. In order to minimize the effect of the problems caused by C. albiceps, the pathogenicity of the Beauveria bassiana (Balsamo) Vuillemin (URM 3447), in vitro, over eggs, larvae and adults in acclimatized laboratorial conditions under the temperature of 28 ± 1 C was evaluated. Suspensions of conidia (104, 105, 106, 107 and 108 conidia.mL-1) were done, for the analysis of the biological parameters. In the bioassay with eggs, the percentage of eclosion varied from 84.81 to 97.22%. In the bioassay with larvae, pre-pupa period varied from 1 to 1.04 and of pupa, from 5 to 5.09 days; the percentage of adult emergency from treated larvae varied from 30.88 to 80.82%. As to the bioassay with adults, the longevity for male and female was of 4.51 to 6.77 and 10.19 to 14.67 days, respectively; the accumulated mortality death on the 7th day varied from 47.50 to 81.20% for males and of 23.70 to 55.00% for females; the period of posture varied from 10 to17.75 days and the percentage of larvae appeared from females infected varied from 71.39 to 91.25%. KEY WORDS: Biological parameters, entomopathogenic fungus, pathogenicity.
Chrysomya albiceps (Wiedemann) é um importante vetor de doenças de animais e humanos, e também causador de miíases secundárias. Avaliou-se a patogenicidade de Beauveria bassiana (Balsamo) Vuillemin (URM 3447), in vitro, sobre ovos, larvas e adultos em condições de laboratório climatizado sob a temperatura de 28 ± 1 C. Foram feitas suspensões de conídios (104, 105, 106, 107 e 108 conídios.mL-1), para análise dos parâmetros biológicos. No bioensaio com ovos, o percentual de eclosão variou de 84,81% a 97,22%. No bioensaio com larvas, o período de pré-pupa variou de 1 a 1,04 e de pupa, de 5,00 a 5,09 dias; o percentual de emergência de adultos a partir de larvas tratadas variou de 30,88% a 80,82%. No bioensaio com adultos, a longevidade para machos e fêmeas foi de 4,51 a 6,77 e 10,19 a 14,67 dias, respectivamente; a mortalidade acumulada no 7 dia variou de 47,50 % a 81,20% para machos e de 23,70 % a 55,00% dias para fêmeas; o período de postura variou de 10 a 17,75 dias e o percentual de larvas eclodidas a partir de fêmeas infectadas variou de 71,39% a 91,25%. PALAVRAS-CHAVES: Fungo entomopatogênico, parâmetros biológicos, patogenicidade.
ABSTRACT
Chrysomya albiceps (Wiedemann) is an important vector of animal and diseases as well as causer of secondary myiasis. In order to minimize the effect of the problems caused by C. albiceps, the pathogenicity of the Beauveria bassiana (Balsamo) Vuillemin (URM 3447), in vitro, over eggs, larvae and adults in acclimatized laboratorial conditions under the temperature of 28 ± 1 C was evaluated. Suspensions of conidia (104, 105, 106, 107 and 108 conidia.mL-1) were done, for the analysis of the biological parameters. In the bioassay with eggs, the percentage of eclosion varied from 84.81 to 97.22%. In the bioassay with larvae, pre-pupa period varied from 1 to 1.04 and of pupa, from 5 to 5.09 days; the percentage of adult emergency from treated larvae varied from 30.88 to 80.82%. As to the bioassay with adults, the longevity for male and female was of 4.51 to 6.77 and 10.19 to 14.67 days, respectively; the accumulated mortality death on the 7th day varied from 47.50 to 81.20% for males and of 23.70 to 55.00% for females; the period of posture varied from 10 to17.75 days and the percentage of larvae appeared from females infected varied from 71.39 to 91.25%. KEY WORDS: Biological parameters, entomopathogenic fungus, pathogenicity.
Chrysomya albiceps (Wiedemann) é um importante vetor de doenças de animais e humanos, e também causador de miíases secundárias. Avaliou-se a patogenicidade de Beauveria bassiana (Balsamo) Vuillemin (URM 3447), in vitro, sobre ovos, larvas e adultos em condições de laboratório climatizado sob a temperatura de 28 ± 1 C. Foram feitas suspensões de conídios (104, 105, 106, 107 e 108 conídios.mL-1), para análise dos parâmetros biológicos. No bioensaio com ovos, o percentual de eclosão variou de 84,81% a 97,22%. No bioensaio com larvas, o período de pré-pupa variou de 1 a 1,04 e de pupa, de 5,00 a 5,09 dias; o percentual de emergência de adultos a partir de larvas tratadas variou de 30,88% a 80,82%. No bioensaio com adultos, a longevidade para machos e fêmeas foi de 4,51 a 6,77 e 10,19 a 14,67 dias, respectivamente; a mortalidade acumulada no 7 dia variou de 47,50 % a 81,20% para machos e de 23,70 % a 55,00% dias para fêmeas; o período de postura variou de 10 a 17,75 dias e o percentual de larvas eclodidas a partir de fêmeas infectadas variou de 71,39% a 91,25%. PALAVRAS-CHAVES: Fungo entomopatogênico, parâmetros biológicos, patogenicidade.
ABSTRACT
The partial characterization of extracellular proteases from Streptomyces clavuligerus NRRL 3585 and 644 mutant was investigated. The enzyme production was carried out in batch fermentation using soy bean filtrate as nitrogen source. Maximum activity was obtained after 96h of fermentation with an initial pH of 7.0. The enzyme was partially purified by ammonium sulphate precipitation. Enzymes from the two strains retained 37% of their initial activities at pH 8.0 after 2 h incubation at 25ºC. Enzyme half-life at pH 8.0 and 60ºC was 40.30 and 53.32 min, respectively for both strains (partially purified extract). The optimum pH was obtained at pH 7.0-8.0 and 8.4 for enzymes produced for 3585 and 644 strains (crude extract), respectively, and 8.4 and 8.0 for enzymes from the partially purified extract 3585 and 644 strains, respectively. The optimum temperature for the crude extract was 21ºC for both strains. However, for the partially preparation the optimum temperature was 50ºC and 40°C for S. clavuligerus NRRL 3585 and 644 strains respectively.
A caracterização parcial de proteases extracelulares de Streptomyces clavuligerus foi investigada. A produção da enzima foi realizada pela fermentação em batelada utilizando farinha de soja como fonte de nitrogênio. O máximo rendimento foi obtido após 96 horas de fermentação com um pH inicial de 7,0. A enzima foi purificada parcialmente por precipitação com sulfato de amônia. Ambas enzimas reteram 37% de sua atividade inicial a pH 8,0, após 2 horas de incubação a 25ºC. O tempo de meia-vida das enzimas foi de 40,30 e 53,32 minutos, respectivamente para ambos 3585 e 644 (extrato parcialmente purificado) a pH 8,0 e 60ºC. Com relação ao pH, a atividade ótima foi alcançada a pH 7,0-8,0 e 8,4 para enzimas produzidas pelas amostras 3585 e 644 (extrato bruto) respectivamente e 8,4 e 8,0 para as enzimas obtidas a partir dos extratos parcialmente purificados das amostras 3585 e 644, respectivamente. A temperatura ótima para o extrato bruto foi de 21ºC para S. clavuligerus NRRL 3585 e 644. Contudo, para a preparação parcialmente purificada, a temperatura ótima foi de 50 e 40ºC para amostras S. clavuligerus NRRL 3585 e 644 respectivamente.