Estudo cariotípico de duas espécies brasileiras do gênero Micrurus (Ophidia: Elapidae) / Karyotypic studies of two Brazilian species of the genus Micrurus (Ophidia: Elapidae)

Descrevemos neste trabalho o cariótipo de duas espécies de cobra coral (Ophidia: Elapidae) do Brasil: Micrurus corallinus e M. ibiboboca. Preparações citológicas foram obtidas através da técnica de esmagamento, seguida de coloração convencional com Giemsa. Encontramos para M. corallinus, um número diplóide (2n) de 40 cromossomos, com fórmula cariotípica 40 (4; 16; 20) e constricção secundária no segundo par de macrocromossomos subtelocêntricos. Micrurus ibiboboca apresentou 2n = 42, com fórmula cariotípica 42 (2; 20; 20) e constricção secundária no primeiro par de macrocromossomos telocêntricos. As primeiras descrições dos cariótipos das espécies M. corallinus e M. ibiboboca, apresentadas neste trabalho, mostram aspectos semelhantes aos cariótipos de M. lemniscatus e M. surinamensis, únicas espécies deste gênero da América do Sul analisadas cromossomicamente. As quatro espécies em questão apresentam o mesmo número de microcromossomos (20), os maiores valores de macrocromossomos telocêntricos ou subtelocêntricos e os maiores números diplóides (2n) já encontrados no gênero Micrurus. Tais características diferenciam estas espécies da América do Sul das nove da América Central com cariótipos já estudados.

The karyotypes of two brazilian species of coral snakes (Ophidia: Elapidae): Micrurus corallinus and M. ibiboboca are described for the first time. Cytological preparations were obtained through the technique of squashing, followed by conventional Giemsa staining. The diploid number for Micrurus corallinus was 40 chromosomes with a karyotype formulae 40 (4; 16; 20) with a secondary constriction in the second pair of subtelocentric macrochromosomes. Micrurus ibiboboca is described by the formulae 42 (2; 20; 20) with 2n = 42 with a secondary constriction in the first pair of telocentric macrochromosomes. The karyotypes of M. corallinus and M. ibiboboca present aspects similar to M. lemniscatus and M. surinamensis, the only previously analyzed species of this genus in South America. These four species have the same number of microchromosomes (20), the largest number of telocentric or subtelocentric macrochromosomes and the largest diploid numbers (2n) ever found in the genus Micrurus. These characteristics differ from those of the nine known species of Central America.

The structure of the nasal chemosensory system in squamate reptiles. 2. Lubricatory capacity of the vomeronasal organ.

The vomeronasal organ is a poorly understood accessory olfactory organ, present in many tetrapods. In mammals, amphibians and lepidosaurian reptiles, it is an encapsulated structure with a central, fluid-filled lumen. The morphology of the lubricatory system of the vomeronasal organ (the source of this fluid) varies among classes, being either intrinsic (mammalian and caecilian amphibian vomeronasal glands) or extrinsic (anuran and urodele nasal glands). In the few squamate reptiles thus far examined, there are no submucosal vomeronasal glands. In this study, we examined the vomeronasal organs of several species of Australian squamates using histological, histochemical and ultrastructural techniques, with the goal of determining the morphology of the lubricatory system in the vomeronasal organ. Histochemically, the fluid within the vomeronasal organ of all squamates is mucoserous, though it is uncertain whether mucous and serous constituents constitute separate components. The vomeronasal organ produces few secretory granules intrinsically, implying an extrinsic source for the luminal fluid. Of three possible candidates, the Harderian gland is the most likely extrinsic source of this secretion.

The structure of the nasal chemosensory system in squamate reptiles. 1. The olfactory organ, with special reference to olfaction in geckos.

The luminal surface of the chemosensory epithelia of the main olfactory organ of terrestrial vertebrates is covered by a layer of fluid. The source of this fluid layer varies among vertebrates. Little is known regarding the relative development of the sources of fluid (sustentacular cells and Bowman's glands) in reptiles, especially in gekkotan lizards (despite recent assertions of olfactory speciality). This study examined the extent and morphology of the main olfactory organ in several Australian squamate reptiles, including three species of gekkotans, two species of skinks and one snake species. The olfactory mucosa of two gekkotan species (Christinus marmoratus and Strophurus intermedius) is spread over a large area of the nasal cavity. Additionally, the sustentacular cells of all three gekkotan species contained a comparatively reduced number of secretory granules, in relation to the skinks or snake examined. These observations imply that the gekkotan olfactory system may function differently from that of either skinks or snakes. Similar variation in secretory granule abundance was previously noted between mammalian and non-mammalian olfactory sustentacular cells. The observations in gekkotans suggests that the secretory capacity of the non-mammalian olfactory sustentacular cells show far more variation than initially thought.

Acidentes ofídicos causados por Bothrops moojeni: correlaçäo do quadro clínico com o tamanho da serpente / Snake bites by Bothrops moojeni: correlation of the clinical picture with the snake size

Durante um período de 19 meses (março 1986 a setembro 1987) foram estudados 22 casos de acidentes ofídicos causados por Bothrops moojeni na regiäo de Säo José do Rio Preto, Säo Paulo, nos quais o tamanho da serpente foi sistematicamente medido. Foram constituídos dois grupos de pacientes de acordo com o tamanho da serpente: grupo I - 9 casos de serpentes pequenas (30 a 53 cm) e grupo II - 13 casos de serpentes grandes (80 a 147cm). Os resultados mostraram: 1. efeitos locais iniciais - dor e edema - mais leves no grupo I; 2. tempo de coagulaçäo prolongado/incoagulável levemente mais freqüente no grupo I; 3. complicaçöes locais - necrose, infecçäo e síndrome compartimental - exclusivamente, e em mais da metade dos casos do grupo II, apesar da terapia com antiveneno ter sido mais rápida e em dosis maiores nesse grupo. Conclui-se que as serpentes Bothrops moojeni maiores apresentam grande incremento nas suas açöes locais - edema, necrose e infecçäo secundária - e leve perda em sua açäo coagulante

Cartilha de ofidismo / Snake poisoning's primer

Cartilha destinada às equipes de saúde e a todos que se interessam em trabalhar no controle de acidentes ofídicos