Venenos e toxinas ofídicas purificadas como ferramenta biotecnológica para o controle de Ralstonia solanacearum

The objective of this work was to evaluate the in vitro antibacterial activity of snake venoms and purified toxins on the phytopathogenic bacterium Ralstonia solanacearum. The evaluations were performed with 17 crude venoms (13 from Bothrops, 3 from Crotalus, and 1 from Lachesis) and seven toxins (1 from Bothrops and 6 from Crotalus). Antibacterial activity was assessed in MB1 medium containing solubilized treatments (1 μL mL‑1). A total of 100 μL bacterial suspension (8.4 x 109 CFU mL-1) was used. After incubation at 28°C, the number of bacterial colonies at 24, 48, and 72 hours after inoculation was evaluated. SDS-PAGE gel at 15% was used to analyze the protein patterns of the samples, using 5 μg protein of each sample in the assay. Furthermore, the minimum inhibitory concentration (MIC) and lethal concentration (LC50) values were determined by the Probit method. Venoms and toxins were able to reduce more than 90% of R. solanacearum growth. These results were either equivalent to those of the positive control chloramphenicol or even better. While MIC values ranged from 4.0 to 271.5 µg mL-1, LC50 ranged from 28.5 µg mL-1 to 4.38 mg mL-1. Ten crude venoms (7 from Bothrops and 3 from Crotalus) and two purified toxins (gyroxin and crotamine) are promising approaches to control the phytopathogenic bacterium R. solanacearum.O objetivo deste trabalho foi avaliar a atividade antibacteriana in vitro de venenos e toxinas purificadas de serpentes sobre a bactéria fitopatogênica Ralstonia solanacearum. As avaliações foram realizadas em 17 venenos brutos (13 de Bothrops, 3 de Crotalus e 1 de Lachesis) e sete toxinas (1 de Bothrops e 6 de Crotalus). A atividade antibacteriana foi avaliada em meio MB1 que continha os tratamentos solubilizados (1 μL mL-1). Utilizou-se o total de 100 μL de suspensão bacteriana (8,4 x 109 UFC mL-1). Após incubação a 28°C, avaliou-se o número de colônias bacterianas às 24, 48 e 72 horas após a inoculação. O gel SDS-PAGE a 15% foi usado para analisar o perfil proteico das amostras, tendo-se utilizado 5 μg de proteína no ensaio. Além disso, os valores de concentração inibitória mínima (CIM) e concentração letal (CL50) foram determinados pelo método Probit. Os venenos e as toxinas foram capazes de reduzir mais de 90% do crescimento de R. solanacearum. Esses resultados foram ou equivalentes aos do controle positivo cloranfenicol ou até melhores. Enquanto os valores de CIM variaram de 4,0 a 271,5 µg mL-1, a CL50 variou de 28,5 µg mL-1 a 4,38 mg mL-1. Dez venenos brutos (7 de Bothrops e 3 de Crotalus) e duas toxinas (giroxina e crotamina) são abordagens promissoras para o controle da bactéria fitopatogênica R. solanacearum

Flutuação sazonal de Dermatobia hominis em peles bovinas oriundas de matadouro

Realizou-se o estudo do efeito da temperatura, precipitação pluviométrica e da umidade relativa sobre a flutuação sazonal de larvas de Dermatobia hominis em 5.142 peles de bovinos. As peles foram obtidas junto a um matadouro localizado no município de Piraí, estado do Rio de Janeiro, Brasil, durante o período de novembro de 1995 a outubro de 1997. Os maiores picos de peles parasitadas por berne foram observados em novembro de 1995 e dezembro de 1996. Picos menores de infestação foram observados nos meses de março e maio de 1996 e março de 1997, quando também foram observadas altas porcentagens de peles infestadas. O aumento na porcentagem de peles parasitadas acompanhou o aumento da temperatura média mensal, sendo que temperaturas iguais ou maiores que 25ºC se mostraram benéficas ao aumento na porcentagem de peles parasitadas, assim como a precipitação pluviométrica, onde observou-se que períodos de chuvas mensais acima de 200 mm³ favoreceram ao aumento da porcentagem de peles parasitadas. As menores porcentagens de peles parasitadas por berne foram observadas durante o período de junho a outubro de 1996 e de 1997, quando verificou-se temperaturas médias mensais variando entre 21ºC e 22,5ºC, sendo que estas não se mostraram favoráveis ao aumento na porcentagem de peles parasitadas, assim como, precipitações pluviométricas mensais menores que 50 mm³. Das 5.142 peles examinadas, 2.710 (52,7%) encontravam-se parasitadas pelo berne

GENOTYPE CHARACTERIZATION OF THE Haematobia irritans (DIPTERA: MUSCIDAE) FROM BRAZIL, DOMINICAN REPUBLIC AND COLOMBIA BASED ON RANDOMLY AMPLIFIED POLYMORPHIC DNA (RAPD) ANALYSIS

Blood-sucking flies are important parasites in animal production systems, especially regarding confinement conditions. Haematobia irritans, the horn fly, is one of the most troublesome species within bovine production systems, due to the intense stress imposed to the animals. H. irritans is one of the parasites of cattle that cause significant economic losses in many parts of the world, including South America. In the present work, Brazilian, Colombian and Dominican Republic populations of this species were studied by Random Amplified Polymorphic DNA(RAPD) to assess basically genetic variability between populations. Fifteen different decamer random primers were employed in the genomic DNA amplification, yielding 196 fragments in the three H. irritans populations. Among h. irritans samples, that from Colombia produced the smallest numbers of polymorphic hands. This high genetic homogeneity may be ascribed to its geographic origin, which causes high isolation, low gene flow, unlike the other American populations, from Brazil and Dominican Republic. Molecular marker fragments, which its produced exclusive bands, detected in every sample enabled the population origin to be characterized, but they are also potentially useful for further approaches such as the putative origin of Brazilian, Colombian and Dominican Republic populations of horn fly from South America. Similarity indices produced by chemo metric analysis showed the closest relationships between flies from Brazil and Dominican Republic, while flies from Colombia showed the greatest genotypic differentiation relative to the others populations.CAPESCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Description on the larva of Amblyomma pacae Aragão, 1911 (Acari: Ixodidae) by light and scanning electron microscopy

The larval stage of Amblyomma pacae Aragão is described using optical and scanning electron microscopy. Unfed larvae were obtained from a colony of A. pacae originating from engorged females collected on Agouti paca (Linnaeus) from Monte Negro County, state of Rondônia, Western Amazon, Brazil. Several morphological characters are described for the first time, including the chaetotaxy of the idiosoma, palpi and Haller s organ, as well as morphological features of the idiosoma, gnathosoma and legs. The topographical and numerical patterns of integumentary pores (porotaxy) of the larva are described using a recently proposed nomenclature. Only a few morphological differences were observed between the A. pacae larva and other Amblyomma spp. larvae previously described from Brazil; however, some of these characters can be used to differentiate A. pacae from other species of this genu

Description on the larva of Amblyomma ovale Koch, 1844 (Acari: Ixodidae) by light and scanning electron microscopy

The larval stage of Amblyomma ovale Koch is described using optical and scanning electron microscopy. Unfed larvae were obtained from a colony of A. ovale originating from engorged females collected on domestic dogs from Monte Negro County, state of Rondônia, Western Amazon, Brazil. Fifteen larvae were prepared and mounted on slides, and observed under a light microscope equipped with a drawing tube. Five specimens were prepared for scanning electron microscopy. Several morphological characters are described for the first time, inc1uding the chaetotaxy of the idiosoma, palps and Haller's organ, as well as morphological features of the idiosoma, gnathosoma and legs. In addition, topographical and numerical patterns of integumentary pores (porotaxy) on the idiosoma of larval A. ovale are described using a recently proposed nomenc1ature. Three types of integumentary pores were identified on the idiosoma of A. ovale larvae: lyrifissures, small glands, and large wax glands. These structures were observed isolated or associated over the entire idiosoma, except on the scutum, which lacks large wax glands. Larvae of A. ovale showed similar topographical and numerical patterns of integumentary structures, with 6 pairs of large wax glands (I pair dorsal/5 pairs ventral), 24 pairs of Iyrifissures (11 pairs dorsal/13 pairs ventral), and 54 pairs of small glands (32 pairs dorsal/22 pairs ventral). These topographical and numerical patterns of integumentary structures of larval A. ovale showed only minor differences when compared with patterns of other Amblyomma larvae; however, a few key features can be used to differentiate A. ovale from other members of its genu

Anaplasma marginale infection in cattle from south-western Amazonia

The present study provides the first epidemiological data regarding infection by Anaplasma marginale in cattle reared in south-western Brazilian Amazonia. One simple procedure was adapted for the extraction of DNA from blood clots collected in seven microregions of Rondônia State and two mesoregions of Acre State. PCR method was used to asses the frequency of A. marginale infections in 4 to12-month-old cattle. The cattle infection was investigated by polymerase chain reaction (PCR) using the specific primer "msp5" for A. marginale. The DNA amplifications revealed that the mean frequency of A. marginale infection was 98.6% (1,627/1,650) in samples from Rondonia, and 92.87% (208/225) in samples from Acre. The high frequency of A. marginale infections in 4 to 12-month-old cattle indicate a situation of enzootic stability in the studied areas and are comparable to those detected by immunodiagnosis in different endemic regions in Brazil. The DNA extraction of clotted blood method described here can be used for epidemiological studies on anaplasmosis and other bovine hemoparasites

Anaplasma marginale infection in cattle from south-western Amazonia Infecção por Anaplasma marginale em bovinos na Amazônia Sul Ocidental, Brasil

The present study provides the first epidemiological data regarding infection by Anaplasma marginale in cattle reared in south-western Brazilian Amazonia. One simple procedure was adapted for the extraction of DNA from blood clots collected in seven microregions of Rondônia State and two mesoregions of Acre State. PCR method was used to asses the frequency of A. marginale infections in 4 to12-month-old cattle. The cattle infection was investigated by polymerase chain reaction (PCR) using the specific primer "msp5" for A. marginale. The DNA amplifications revealed that the mean frequency of A. marginale infection was 98.6% (1,627/1,650) in samples from Rondonia, and 92.87% (208/225) in samples from Acre. The high frequency of A. marginale infections in 4 to 12-month-old cattle indicate a situation of enzootic stability in the studied areas and are comparable to those detected by immunodiagnosis in different endemic regions in Brazil. The DNA extraction of clotted blood method described here can be used for epidemiological studies on anaplasmosis and other bovine hemoparasites.O presente estudo fornece os primeiros dados epidemiológicos relativos a infecção por Anaplasma marginale em bovinos criados na Amazônia Sul Ocidental brasileira. Foi adaptado um procedimento simples para a extração de DNA a partir de coágulos sanguíneos coletados em sete microrregiões do estado de Rondônia e duas mesoregiões do estado do Acre. A técnica da reação em cadeia da polimerase (PCR) foi aplicada para avaliar a freqüência da infecção por A. marginale em bovinos com idade entre 4 e 12 meses. Após a extração do DNA de cada amostra, a infecção nos bovinos foi investigada pela amplificação do gene "msp5" de A. marginale. As técnicas de amplificação do DNA revelaram que a freqüência de infecção por A. marginale foi de 98,6% (1.627/1.650) nas amostras provenientes de Rondônia e de 92,87% (208/225) nas amostras do Acre. A alta freqüência da infecção por A. marginale nos animais com idade entre 4 e 12 meses indica uma situação de estabilidade enzoótica nas regiões estudadas, as quais são comparáveis às detectadas por técnicas de imunodiagnóstico em outras regiões endêmicas no Brasil. A extração do DNA através do método aqui descrito pode ser utilizado em estudos epidemiológicos sobre a anaplasmose bovina e outros hemoparasitas