Método de amostragem e caracterização química da forragem consumida por bovinos em pasto consorciado de aveia e azevém / Method of sampling and chemical characterization of forage intake by cattle in pasture ryegrass intercropping oats

O presente ensaio foi conduzido com o objetivo de se estudarem diferentes métodos de amostragem de pasto e de se estimar a composição química da dieta consumida por novilhos Holandeses, mantidos em pastagem consorciada de aveia preta (Avena strigosa Schreb) e azevém (Lolium multiflorum Lam). Os métodos avaliados foram o corte da forragem rente ao solo (CFRS), o pastejo simulado (PSI) e a coleta de extrusa ruminal (CERU). Os teores médios de proteína bruta (PB), nutrientes digestíveis totais (NDT), fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA) foram de 9,7; 62,2; 64,5 e 33,1% para o tratamento CFRS; de 9,8; 65,4; 59,6 e 30,0% para o PSI, e de 11,4; 70,8; 51,6 e 25,5% para CERU, respectivamente. Não houve diferença estatística entre os métodos CFRS e PSI, todavia, em relação ao método CERU, ambos subestimaram a concentração proteica e a energética, e superestimaram a quantidade de parede celular presente na dieta. Conclui-se que a coleta da extrusa ruminal pode ser um método adequado para caracterizar a dieta consumida por novilhos em pastagem consorciada de aveia e azevém.

The experiment was conducted to study different methods of pasture sampling, to estimate the chemical composition of the diet of Holstein steer, and grazing pasture of oat (Avena strigosa Schreb)and ryegrass (Lolium multiflorum Lam). The methods evaluated were Clipping Close by Soil (CCS), Hand-Plucking (HPL) and Rumen Evacuation (REV). The averages for crude protein (CP), total digestible nutrients (TDN), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were 9.7, 62.2, 64.5 and 33.1% for the CCS treatment; 9.8, 65.4, 59.6 and 30.0% for HPL, and 11.4, 70.8, 51.6 and 25.5% for REV, respectively. There was no statistical difference between CCS and HPL methods, however, in relation to the REV method, both underestimated protein and energy concentration, and overestimated the amount of cell walls in the diet. The conclusion is that rumen evacuation may be an adequate method to characterize the diet consumed by steers on oats and ryegrass pastures.

Phenotyping and genotyping methods applied to investigate the relatedness of Brazilian isolates of Enterobacter cloacae

In order to evaluate the resolving power of several typing methods to identify relatedness among Brazilian strains of Enterobacter cloacae, we selected twenty isolates from different patients on three wards of a University Hospital (Orthopedics, Nephrology, and Hematology). Traditional phenotyping methods applied to isolates included biotyping, antibiotic sensitivity, phage-typing, and O-serotyping. Plasmid profile analysis, ribotyping, and macrorestriction analysis by pulsed-field gel electrophoresis (PFGE) were used as genotyping methods. Sero- and phage-typing were not useful since the majority of isolates could not be subtyped by these methods. Biotyping, antibiogram and plasmid profile permitted us to classify the samples into different groups depending on the method used, and consequently were not reliable. Ribotyping and PFGE were significantly correlated with the clinical epidemiological analysis. PFGE did not type strains containing nonspecific DNase. Ribotyping was the most discriminative method for typing Brazilian isolates of E. cloacae

Mini-Mu insertions in the tetracycline resistence determinant from proteus mirabilis

The inducible tetracycline resistance determinant isolated from Proteus mirabilis cloned into the plasmid pACYC177 was mutagenized by insertion of a mini-Mu-lac phage in order to define the regions in the cloned sequences encoding the structural and regulatory proteins. Three different types of mutants were obtained: one lost the resistance phenotype and became Lac+; another expressed the resistance at lowerlevels and constitutively; the third was still dependent on induction but showed a lower minimal inhibitory concentration. The mutant phenotypes and the locations of the insertions indicate that the determinant is composed of a repressor gene and a structural gene which are not transcribed divergently as are other known tetracycline determinants isolated from Gram-negative bacteria.

Vibrio fluvialis attachs to but does not enter Hela cell monolayers

Considering the possibility that invasiveness could be a neglected factor of virulence in Vibrio fluvialis-linked enteritis, since a dysenteric form of the disease was seen in Bangladesh, we studied 12 Brazilian strains of the organism, six clinical and six environmental, to determine whether they might be able to enter into HeLa cell monolayers or would carry plasmids incidentally involved in invasiveness. Four human and two environmental isolates attached to but did not enter into the cells. Though five strains harbored plasmids,no relationship was found between the carriage of these genetic elements and adhesiveness

Isolation of urease-positive Vibrio parahaemolyticus from diarrheal patients in northeast Brazil

De 21 linhagens de Vibrio parahaemolyticus, isoladas de fezes humanas, na costa Nordeste do Brasil, oito (38 por cento) foram urease positivas. A maioria dessas linhagens, em contraste com as ureases negativas, nao produziram a hemolisina responsavel pelo fenomeno Kanagawa.

Gastroenteritis humanas associadas a Vibrio parahaemolyticus no Recife, Brasil / Human gastroenteritis associated with Vibrio parahaemolyticus in Recife, Brazil

Realizou-se estudo sobre a ocorrencia do Vibrio parahaemolyticus em 1.100 fezes diarreicas, enviadas rotineiramente a laboratorio clinico privado do Recife, para diagnostico microbiologico. Isolou-se o V. parahaemolyticus de 14 (1,3 por cento) amostras fecais. Entretanto, se nos consideramos apenas os especimes dos pacientes adultos, a taxa de isolamento de V. parahaemolyticus elevou-se para 7,1 por cento. Na maioria dos casos (92,86 por cento), o V. parahaemolyticus foi o unico enteropatogeno reconhecido. Demonstraram-se sete antigenos K entre as cepas isoladas e tres nao puderam ser sorotipadas. Apenas duas linhagens, ambas ureoliticas, nao produziram a toxina direta termoestavel. Nos concluimos que o V, parahaemolyticus e importante causa de diarreia do adulto no Recife, em consumidores de frutos do mar.