Social Reinforcement Delays in Free-Flying Honey Bees (Apis mellifera L.)

Free-flying honey bees (Apis mellifera L.) reactions were observed when presented with varying schedules of post-reinforcement delays of 0 s, 300 s, or 600 s. We measured inter-visit-interval, response length, inter-response-time, and response rate. Honey bees exposed to these post-reinforcement delay intervals exhibit one of several patterns compared to groups not encountering delays, and had longer inter-visit-intervals. We observed no group differences in inter-response time. Honey bees with higher response rates tended to not finish the experiment. The removal of the delay intervals increased response rates for those subjects that completed the trials.     

The binding of folyl polyglutamates by hemoglobin

Pteroyl polyglutamates bind to hemoglobin with an affinity which leaves only a minor fraction of red cell folate in the free state. This could serve as a regulating mechanism for protein synthesis in the differentiating erythroblast.     

Control of mRNA translation in oocytes and developing embryos of giant moths. I. Function of the 5' terminal "Cap"in the tobacco hornworm, Manduca sexta

Injection of labeled leucine into oocytes and developing embryos of the tobacco hornworm, Manduca sexta, revealed that the rate of protein synthesis increases dramatically after fertilization and continues to rise until gastrulation. Cell-free preparations of oocytes and developing embryos show a similar pattern of in vitro incorporation. When messenger RNA extracted from unfertilized oocytes was examined by gradient density centrifugation under denaturing conditions, a broad peak was observed which centered around 15 S. In contrast to mRNA extracted from oocytes, that from embryos was found to be capped by 7-methylguanosine at the 5′ terminus. When translation of oocyte mRNA was compared with that of embryo mRNA in a cell-free translation system derived from wheat germ, oocyte RNA translated less efficiently. In the presence of an inhibitor of methylation, S-adenosylhomocysteine, the differences were further widened. In competition with a cap analog, 7-methylguanosine 5′-monophosphate, embryo mRNA translation was inhibited more than oocyte at low concentrations of analog. These results are taken to indicate that the lack of a cap at the 5′ terminus could be one mechanism to inhibit translation prior to fertilization.