Development and regeneration of circadian clock

1.研究了不同光照条件下板栗卵孵化过程中孵化的时间分布。结果表明，通过中期胚胎发育，胚胎生物钟已经形成，并可携带到24小时的光/暗周期。此外，父母(可能是母亲)所处的光周期条件会影响卵子孵化的时间，这表明母体因素控制着卵子孵化的时间。在最原始的后生动物门--日本涡虫中，检测到了5-羟色胺。5-羟色胺定位于头神经节(脑)、从脑向后延伸的主要神经索和连接主要神经索的连合轴突。5-羟色胺水平随昼夜节律波动，证明了昼夜节律计时机制的存在。为了研究褪黑素对体外受精和胚胎发育的影响，将体外受精后的小鼠胚胎培养在含有或不含有褪黑素的生理培养液中。褪黑素可提高受精率和早期胚胎发育率。测定了体外受精妇女排卵前卵泡液中去甲肾上腺素的浓度，并与目前测定的外周血浆中去甲肾上腺素的浓度进行了比较。所有卵泡液样本中去甲肾上腺素的浓度均显著高于相应的血浆样本。每名妇女卵泡液和血浆中去甲肾上腺素水平呈正相关。这些数据表明，卵泡液中去甲肾上腺素的主要来源可能是全身循环。

1. Temporal profiles of hatching in cricket (Gryllus bimaculatus) eggs incubated under different lighting regimens were examined. The results demonstrate that, by midembryogenesis, the embryonic circadian clock has been formed and is entrainable to 24-h light/dark cycles. In addition, the photoperiodic conditions to which the parents (probably the mothers) have been exposed influence the timing of egg hatching, suggesting that maternal factors regulate the timing of egg hatching.2. In the freshwater planarian Dugesia japonica, which belongs to most primitive metazoan phylum, serotonin was detected. Serotonin was localized in the cephalic ganglion (brain), in the main nerve cords extending posteriorly from the brain and in the commissure axons connecting the main nerve cords. The serotonin levels fluctuated with circadian rhythm, demonstrating the existence of a circadian timekeeping mechanism in planarian.3. To examine the effect of melatonin on in vitro fertilization and embryonic development, mouse embryos alter insemination in vitro were cultured in a physiological medium with or without melatonin. Melatonin increased the fertilization rate and the rate of early embryo development.4. The concentrations of noradrenaline in preovulatory follicular fluid obtained from women undergoing in vitro fertilization were determined and compared with those in peripheral plasma obtained currently. All of the follicular fluid samples contained noradrenaline at concentrations substantially higher than those in the corresponding plasma samples. A positive correlation was found between noradrenaline levels in follicular fluid and plasma in each woman. The data suggest that the main source of noradrenaline in the follicular fluid could be the general circulation.