Phylogenetic and pathotype analysis of Escherichia coli swine isolates from Southern Brazil

The current study evaluated the presence of virulence factors by a multiplex PCR technique and then phylogenetically classified the studied strains into groups A, B1, B2 and D, according to Clermont et al. (2000), in 152 intestinal and extraintestinal swine isolates of Escherichia coli. Seventy seven isolates tested were positive for virulence factors. Phylogenetic characterization placed 21 samples into group A, 65 into B1, 19 into B2 and 47 into D. Fourteen urine samples were classified as uropathogenic E. coli (UPEC), nine were both UPEC and enterotoxigenic E. coli (ETEC) and four were ETEC only. The most common phylogenetic classifications were B1 and D groups. Of the analyzed fecal samples, 25 were classified as ETEC. Phylogenetically, the group of higher occurrence was B1, followed by B2, A and D. For the small intestine samples, 20 were classified as ETEC. Phylogenetic analysis found groups B1 and A to be the most commons in these samples. Six isolated tissue samples were classified as ETEC and most of them were designated as group D by phylogenetic classification. The phylogenetic analysis could be employed in veterinary laboratories in the E. coli isolates screening, including the possibility of vaccine strain selection and epidemiological searches

Arbuscular mycorrhizal fungal communities and soil aggregation as affected by cultivation of various crops during the sugarcane fallow period

Management systems involving crop rotation, ground cover species and reduced soil tillage can improve the soil physical and biological properties and reduce degradation. The primary purpose of this study was to assess the effect of various crops grown during the sugarcane fallow period on the production of glomalin and arbuscular mycorrhizal fungi in two Latosols, as well as their influence on soil aggregation. The experiment was conducted on an eutroferric Red Latosol with high-clay texture (680 g clay kg-1) and an acric Red Latosol with clayey texture (440 g kg-1 clay) in Jaboticabal (São Paulo State, Brazil). A randomized block design involving five blocks and four crops [soybean (S), soybean/fallow/soybean (SFS), soybean/millet/soybean (SMS) and soybean/sunn hemp/soybean (SHS)] was used to this end. Soil samples for analysis were collected in June 2011. No significant differences in total glomalin production were detected between the soils after the different crops. However, total external mycelium length was greater in the soils under SMS and SHS. Also, there were differences in easily extractable glomalin, total glomalin and aggregate stability, which were all greater in the eutroferric Red Latosol than in the acric Red Latosol. None of the cover crops planted in the fallow period of sugarcane improved aggregate stability in either Latosol.Os sistemas de manejo que adotam menor revolvimento do solo, rotação de culturas e utilização de plantas de cobertura podem levar a melhorias dos seus atributos biológicos e físicos, com redução da degradação do solo. O objetivo deste estudo foi avaliar o cultivo de diferentes culturas, durante o período de reforma do canavial, na produção de glomalina e na de propágulos de fungos micorrízicos arbusculares, em dois Latossolos, e a influência desses nos processos de agregação do solo. O experimento foi conduzido no município de Jaboticabal, SP, em um Latossolo Vermelho eutroférrico (LVef) textura muito argilosa (680 g kg-1 de argila) e um Latossolo Vermelho ácrico (LVw) textura argilosa (440 g kg-1 de argila), durante o período de reforma do canavial. O delineamento experimental foi em blocos casualizados com quatro cultivos e cinco blocos. Os cultivos foram: soja; soja/pousio/soja; soja/milheto/soja; e soja/crotalária/soja. A amostragem de solo foi realizada em junho de 2011. Não foram verificadas diferenças significativas na quantidade de glomalina total, após a utilização das diferentes culturas. Maior comprimento de micélio externo total foi observado no solo onde houve os cultivos de soja/milheto/soja e soja/crotalária/soja. Foram observadas diferenças entre os solos avaliados para os atributos glomalina facilmente extraível, glomalina total e índice de estabilidade de agregados do solo, tendo o LVef apresentado características mais favoráveis que o LVw. Nenhuma das culturas utilizadas no período de reforma do canavial teve efeitos benéficos no índice de estabilidade de agregados nos dois Latossolos estudados.UNESP FCAV Department of Soil ScienceUNESP Department of Soil ScienceUNESP FCAV Department of Soil ScienceUNESP Department of Soil Scienc

Avaliação de diferentes osmolaridades de soluções hiposmóticas e tempos de incubação no teste hiposmótico do sêmen de touros Nelore

O objetivo neste estudo foi avaliar diferentes osmolaridades e tempos de incubação durante o teste hiposmótico e suas correlações com a congelabilidade do sêmen de touros zebuínos. Foram utilizados 30 ejaculados de seis touros adultos da raça Nelore. No sêmen in natura foi feita avaliação física e morfológica, classificação quanto à coloração supravital e o teste hiposmótico. No teste hiposmótico foram utilizadas soluções com osmolaridades de 60, 100, 150 mOsm/kg e água destililada (19 mOsm/kg) om 15, 30 e 60 minutos de período de incubação a 37ºC. Após a criopreservação, as amostras foram descongeladas e avaliadas quanto aos testes hiposmótico, à coloração supravital, ao teste de termorresistência lento e à coloração fluorescente. Não foram detectadas interações entre os tempos e as osmolaridades. Não houve diferenças para os valores médios de espermatozoides reativos incubados nas soluções com diferentes osmolaridades para o sêmen congelado/ descongelado. Apenas a utilização de água destilada determinou diferença nos valores médios obtidos no teste hiposmótico realizado no sêmen in natura. Não houve diferença entre os valores médios de espermatozoides reativos incubados com diferentes tempos de incubação, tanto no sêmen in natura como no sêmen congelado/descongelado. O teste hiposmótico pode ser realizado com 15 minutos de incubação, e com uma solução que varie a osmolaridade de 60 a 150 mOsm/kg, tanto no sêmen in natura como no sêmen congelado/descongelado.The objective of this study was to evaluate different osmolarities and incubation times during the hiposmotic test and its correlation with cryopreservation of semen of Zebu bulls. It was used 30 ejaculates from six mature Nelore bulls. It was performed physical and morphological evaluation, supravital staining classification and hiposmotic test in the fresh semen. In the hiposmotic test, solutions with osmolarities of 60, 100, 150 mOsm/kg and distilled water (19 mOsm/kg) were used at 15, 30 and 60 minutes of incubation at 37ºC. After cryopreservation, the samples were thawed and evaluated for hiposmotic test, supravital staining, slow termoresistance test and for fluorescent stain. No interactions were detected between incubation times and solution osmolarities. There were no differences in average values of reactive sperm incubated in different solutions with different osmolarities for frozen/thawed semen. Only the use of distilled water determined differences in the average values obtained in the hiposmotic test performed in fresh semen. There was no difference between the mean values of reactive spermatozoa incubated with different incubation time in both fresh and frozen/thawed semen. Hiposmotic test can be accomplished in 15 minutes of incubation time and with a solution which varies osmolarity from 60 to 150 mOsm/kg in both fresh and frozen/thawed semen