Hermaphroditism among dioecious Tagelus plebeius (Lightfoot, 1786) (Mollusca, Psammobiidae) and Iphigenia brasiliana (Lamarck, 1818) (Mollusca, Donacidae) on the Cachoeira River Estuary, Ilhéus, Bahia, Brazil / Hermafroditismo nos moluscos dióicos Tagelus plebeius (Lightfoot, 1786) (Mollusca, Psammobiidae) e Iphigenia brasiliana (Lamarck, 1818) (Mollusca, Donacidae) na região estuarina do Rio Cachoeira, Ilhéus, Bahia, Brasil

The samples of Tagelus plebeius and Iphigenia brasiliana were manually collected on the Cachoeira River estuary region (Ilhéus, BA, Brazil) between August 2005 and August 2006, with a periodicity of 15 days, with 20 animals collected/sampled, performing 500 samples from each species. The animals were measured, eviscerated and kept in solution of Davidson and after 24-30 hours, they were transferred to ethanol 70 percent. The material was processed for routine histology, with paraffin embedding, obtaining 7 μm thick slices, stained with Harris hematoxilin and Eosin (HE). By light microscopy analysis, 2 cases of hermaphroditism (0.4 percent) in T. plebeius samples and one case (0.2 percent) in I. brasiliana were registered with predominance of female over male follicles.

Os exemplares de Tagelus plebeius e Iphigenia brasiliana foram manualmente coletados na região estuarina do Rio Cachoeira (Ilhéus, Bahia), entre agosto de 2005 e agosto de 2006, com coleta quinzenal de 20 animais, totalizando 500 exemplares/espécie. Os animais foram mensurados, eviscerados e fixados em solução de Davidson por 24-30 horas e depois transferidos para etanol a 70 por cento. O material foi processado por técnica rotineira de histologia, com inclusão em parafina, obtenção de cortes com 7 μm de espessura e coloração por hematoxilina de Harris e Eosina (HE). A análise em microscopia de luz evidenciou 2 casos de hermafroditismo (0,4 por cento) em T. plebeius e um caso (0,2 por cento) em I. brasiliana (0,2 por cento), com predominância de folículos femininos sobre os masculinos.

Obtencion de cromosomas de vieiras a partir de ovocitos / Chromosomes isolation from scallop oocytes

Se describe una metodología para la obtención de cromosomas a partir de ovocitos no fecundados de las vieiras Euvola ziczac y Nodipecten nodosus. Esta metodología resuelve los problemas debidos a la alta concentración de material de reserva en los ovocitos, la condensación excesiva de los cromosomas y la pérdida de material biológico durante su paso de una solución a outra. Es aplicable y adaptable a otros bivalvos.

A cellular approach to the study of complex natural behavior patterns in the ragged sea hare (Bursatella leachii), a marine invertebrate indigenous to Puerto Rico

The ragged sea hare (Bursatella leachii), an aplysiid mollusc indigenous to the tropical waters of Puerto Rico, possesses numerous properties that make it suitable for a neuroethological approach to the study of complex behavior patterns. Field studies spanning three years have established a location and season of Bursatella availability on the north coast of the island. In the natural habitat, the Bursatella exhibit a daily rhythm of behavior patterns in which feeding-related activities predominate during the day and reproductive behaviors predominate at night. Some aspects of this natural pattern persist in animals held in the laboratory. The Bursatella nervous system contains large neurons, some of which appear to be homologous to cells that have been characterized extensively in related species. Following isolation of the nervous system, neural centers associated with feeding movements and locomotion retain extraordinarily robust rhythm generating capabilities. It is proposed that this species offers unique opportunities for deriving general principles governing the regulation and integration of central pattern generator circuits underlying complex natural behavior patterns