RESUMO
Circadian rhythms in social insects are highly plastic and are modulated by multiple factors. In addition, complex behaviors such as sun-compass orientation and time learning are clearly regulated by the circadian system in these organisms. Despite these unique features of social insect clocks, the mechanisms as well as the functional and evolutionary relevance of these traits remain largely unknown. Here we show a modification of the Drosophila activity monitoring (DAM) system that allowed us to measure locomotor rhythms of the honey bee, Apis mellifera (three variants; gAHB, carnica and caucasica), and two paper wasps (Polistes crinitus and Mischocyttarus phthisicus). A side-by-side comparison of the endogenous period under constant darkness (free-running period) led us to the realization that these social insects exhibit significant deviations from the Earth's 24 h rotational period as well as a large degree of inter-individual variation compared with Drosophila. Experiments at different temperatures, using honey bees as a model, revealed that testing the endogenous rhythm at 35°C, which is the hive's core temperature, results in average periods closer to 24 h compared with 25°C (23.8 h at 35°C versus 22.7 h at 25°C). This finding suggests that the degree of tuning of circadian temperature compensation varies among different organisms. We expect that the commercial availability, cost-effectiveness and integrated nature of this monitoring system will facilitate the growth of the circadian field in these social insects and catalyze our understanding of the mechanisms as well as the functional and evolutionary relevance of circadian rhythms.
Assuntos
Abelhas/fisiologia , Ritmo Circadiano , Atividade Motora , Vespas/fisiologia , Animais , Abelhas/genética , Feminino , Especificidade da Espécie , TemperaturaRESUMO
Se propuso una investigación para conocer las diferencias existentes entre placentas provenientes de embarazos normales y de alto riesgo desde el punto de vista de características morfológicas macroscópicas. Se corelacionaron clínico- morfológicamente , 19 embarazos incluyendo estados hipertensivos asociados al embarazo e incompatibilidad Rh y 23 embarazos supuestamente normales. Se encontró que en los embarazos normales hay relación directa entre pesos fetales y placentarios, hay peso promedio mayor de los recien nacidos y sus placentas y edad gestacional media mayor. En los embarazos de alto rieso hay tendencia a producir recien nacidos pre-término con bajo peso para su edad gestacional y placentas pequeñas. En los embarazos con pre-eclampsia se encontró aumento de la relación peso placentario / peso fetal sugiriendo que ante un medio materno desfavorable la placenta se hipertrofía compensatoriamente. Se sugiere para estudios posteriores hacer una investigación utilizando la microscopía de contraste de fase y la inmunofluorescencia