ABSTRACT The anuran skin characteristically has different types of glands, most of which are microscopic and are spread throughout the skin. Some species have specialized regions where glands agglomerate, forming macroglands. The description of the external morphology of Ololygon centralis (Pombal & Bastos, 1996) revealed the presence of an inguinal gland. Ololygon centralis is the only species of the genus that has a macrogland. The present study found these inguinal macroglands to be present only on male specimens, thus characterizing it as a sexually dimorphic skin gland. Microscopic analysis revealed that these glands are composed of many syncytial units involved by myoepithelial cells. The center of the syncytium is full of a proteinaceous secretion with a basic pH and the absence of sugar residues. Similar glands observed in other anuran species have been associated with pheromone production, suggesting that the inguinal glands described for O. centralis males may have a similar function.

O efeito do extrato bruto etanólico da casca do caule da Magonia pubescens foi analisado no tubo digestivo de larvas de terceiro estádio do Aedes aegypti. Diferentes tempos de exposição (2, 4, 6, 8, 10, 12 e 13 horas) foram utilizados com a finalidade de verificar, de forma progressiva, as alterações morfológicas. Os efeitos tóxicos do e.b.e. foram evidenciados, principalmente, ao nível do mesêntero, iniciando-se na região anterior e, estendendo-se para a região posterior. As principais alterações observadas incluíram, destruição total ou parcial das células, alta vacuolização citoplasmática, aumento do espaço subperitrófico, hipertrofia das células e, aparente estratificação epitelial. Essas alterações iniciaram-se após 4 horas de tratamento, sendo que, diferentes graus de destruição foram observados de acordo com o aumento do tempo de exposição ao e.b.e. e com a parte do mesêntero analisado. Este trabalho evidencia o mecanismo de ação do e.b.e. da M. pubescens, ampliando o seu potencial de utilização no controle do A. aegypti.

Crude ethanol extracted from Magonia pubescens trunks was utilized to prove its effect in the intestinal tract of Aedes aegypti 3rd instar larvae. Exposure times (2, 4, 6, 8, 10, 12, and 13 hours) were tested to verify when the morphological alterations begin to occur, in the intestinal tract of the larvae. The toxic effect of the extract was mainly in the midgut, beginning at the anterior midgut and followed through to posterior midgut. The main alterations observed were partial or total cell destruction, high citoplasmatic vacuolization, increase of subperitrophic space, cell hypertrophy and the epithelium did not maintain its monolayer appearance. The alterations began after four hours of exposure to M. pubescens extract. Observations of tissue sections from larvae treated for different lengths of time revealed a wide variation in the degree of damage between exposure periods and midgut larvae region. The present study provides evidence regarding the mode of action of the M. pubescens extract and suggests its potential utilization as a larvicide to control Aedes aegypti mosquito.