Egg-laying rhythm in Drosophila melanogaster.

Extensive research has been carried out to understand how circadian clocks regulate various physiological processes in organisms. The discovery of clock genes and the molecular clockwork has helped researchers to understand the possible role of these genes in regulating various metabolic processes. In Drosophila melanogaster, many studies have shown that the basic architecture of circadian clocks is multi-oscillatory. In nature, different neuronal subgroups in the brain of D. melanogaster have been demonstrated to control different circadian behavioural rhythms or different aspects of the same circadian rhythm. Among the circadian phenomena that have been studied so far in Drosophila, the egg-laying rhythm is unique, and relatively less explored. Unlike most other circadian rhythms, the egg-laying rhythm is rhythmic under constant light conditions, and the endogenous or free-running period of the rhythm is greater than those of most other rhythms. Although the clock genes and neurons required for the persistence of adult emergence and activity/rest rhythms have been studied extensively, those underlying the circadian egg-laying rhythm still remain largely unknown. In this review, we discuss our current understanding of the circadian egg-laying rhythm in D. melanogaster, and the possible molecular and physiological mechanisms that control the rhythmic output of the egg-laying process.

Production of transgenic goat (Capra hircus) with human Granulocyte Colony Stimulating Factor (hG-CSF) gene in Brazil

In order to produce transgenic goats with hG-CSF, a total of 24 adult Saanen and 48 adult undefined breed goats were used as donors and recipients, respectively. Donors were estrus-synchronized with vaginal sponges and superovulated by a treatment with 200 mg FSH given twice daily in decreasing doses over 3 days starting 48 h before sponge removal. Ovulation was induced by injecting 100µg GnRH 36 h after sponge removal. The recipients also received an estrus synchronization treatment. Donors were mated with fertile Saanen bucks and, approximately 72 h after sponge removal, zygotes were recovered surgically by flushing oviducts. The recovered zygotes were briefly centrifuged to a reliable visualization of the pronuclei. The DNA construct containing hG-CSF gene flanked by goat and bovine alphas1-casein sequences was injected into pronuclei of 129 zygotes. The microinjected embryos (3-6 per female) were transferred to 27 recipients. Ten recipients became pregnant and 12 kids were born. One transgenic male founder was identified in the group of kids. This is the first report of a birth of a transgenic goat in Latin America.

A fim de produzir caprinos transgênicos para o hG-CSF, utilizou-se 24 cabras Saanen adultas e 48 cabras sem raça definida adultas como doadoras e receptoras, respectivamente. As doadoras tiveram o estro sincronizado por esponjas vaginais e foram superovuladas com 200 mg de FSH em doses decrescentes, duas vezes ao dia e iniciando 48 h antes da retirada da esponja. A ovulação foi induzida pela injeção de 100 µg de GnRH às 36 h após a retirada da esponja. As receptoras também receberam um tratamento de sincronização do estro. As doadoras foram cobertas por bodes Saanen férteis e, aproximadamente 72 h após a retirada da esponja, os zigotos foram colhidos cirurgicamente por lavagem dos ovidutos. Os zigotos colhidos foram rapidamente centrifugados para uma melhor visualização dos pró-núcleos. A construção de DNA, contendo o gene do hG-CSF flanqueado pelos genes caprino e bovino da alfas1-caseína, foi injetada em 129 embriões. Os embriões microinjetados (3 a 6 por receptora) foram transferidos para 27 receptoras que responderam ao tratamento. Dez receptoras ficaram gestantes e 12 crias foram produzidas. Um macho transgênico fundador foi identificado no grupo de crias nascidas. Este é o primeiro relato do nascimento de um caprino transgênico na América Latina.

¿Cuando un ser humano comienza a ser persona? / When a human being begins to be person?

Después de manifestar la relevancia del tema, se exponen algunos textos de la OPS sobre el mismo, se distinguen varios paradigmas sobre el ser humano y las ideas generales del pensamiento complejo que se relacionan con el tema, las pruebas de la existencia del espíritu como elemento diferenciador o unificador en las definiciones de ser humano y persona, y varios argumentos, con los que se puede concluir cuándo comienza a existir el espíritu en el ser humano. También se propone una referencia, para que la toma de decisiones sobre seres humanos sea ética. El artículo refleja algunas ideas expuestas en el libro Ser humano y persona, editado en el año 2003 por la Universidad de La Sabana y el Celam