Antifungal and marker effects of Talisia esculenta lectin on Microsporum canis in vitro.

AIMS: The purpose of this study was to demonstrate the usefulness of lectin obtained from Talisia esculenta (TEL) seeds as a tool to recognize and study Microsporum canis. For this purpose, we investigated the antifungal and marker action of this lectin and the relationship of these effects with the presence of carbohydrates on the structure of this fungus. METHODS AND RESULTS: The in vitro antifungal activity of TEL was analysed by broth microdilution assay. In addition, TEL was assessed against the arthroconidia present on hairs obtained from infected dogs and cats. The affinity of fluorescein isothiocyanate (FITC)-labelled TEL for macroconidia and arthroconidia of M. canis was also tested. The effects of TEL on the growth of the M. canis strains began with 0.125 mg ml(-1), and 100% inhibition was obtained with a concentration of 2 mg ml(-1). The addition of carbohydrates, especially N-acetyl-glucosamine and d-mannose, inhibited these antifungal effects. TEL was able to inhibit the growth of arthroconidial chitin-rich forms of M. canis obtained from hairs of infected animals and strains cultured in Sabouraud agar. FITC-labelled TEL efficiently marked macroconidial and arthroconidial forms of M. canis, as shown by fluorescent microscopy. CONCLUSIONS: These results show that the inhibitory effects of TEL on M. canis growth may be related to the interaction of lectin with the carbohydrates present at the micro-organism's surface, mainly D-mannose and N-acetyl-glucosamine. SIGNIFICANCE AND IMPACT OF THE STUDY: Talisia esculenta can be used as an important tool in the biochemical study of M. canis or as a molecule to recognize this dermatophyte in infected tissue.

Efeito da endogamia sobre a idade ao primeiro parto de seis rebanhos da raça Nelore / Effect of inbreeding on age at first calving in six Nelore herds

Analisaram-se os registros genealógicos de 1701 novilhas da raça Nelore, nascidas no período de 1967-84, em seis rebanhos localizados nos Estados de Säo Paulo, Mato Grosso e Mato Grosso do Sul. A média ajustada da idade ao primeiro parto foi de 1246,63 mais ou menos 8,53 dias. As análises estatísticas, desenvolvidas pelo método dos quadrados mínimos com números desiguais nas sub-classes, identificaram os efeitos negativos (P<0,01) de reprodutor, populaçäo, ano de nascimento e efeito linear da endogamia. Mês de nascimento näo afetou (P>0,05) a característica em foco. O coeficiente médio de endogamia foi de 4,45 mais ou menos 5,97. Pela regressäo linear, constatou-se que a cada 1 por cento de aumento no coeficiente de endogamia houve correspondente aumento de 3,22 mais ou menos 0,90 dias na idade do primeiro parto