本期Nature Communications上發(fā)表的一項(xiàng)研究報(bào)告說,，魚的一個(gè)名為“血管囊”（saccus vasculosus）的器官起體內(nèi)時(shí)鐘的作用，檢測(cè)白天長(zhǎng)短的季節(jié)差別。
在哺乳動(dòng)物中,，陽光是由眼睛捕捉的，信息被傳遞到腦垂體的結(jié)節(jié)部,，后者將季節(jié)信息再傳給大腦。這個(gè)腺體起一個(gè)季節(jié)時(shí)鐘的作用,，讓大腦知道當(dāng)前是白天還是夜晚,，并將短的天與長(zhǎng)的天區(qū)分開來,，從而能夠?qū)Σ煌竟?jié)進(jìn)行分辨。由于魚沒有結(jié)節(jié)部,，所以一直不清楚它們是否有一個(gè)能夠充當(dāng)季節(jié)傳感器作用的器官。
Takashi Yosimura及其同事在用“馬蘇三文魚”所做的一項(xiàng)研究中,，通過檢測(cè)“血管囊”對(duì)光周期信號(hào)（如白天長(zhǎng)度的變化）的反應(yīng)能力演示了該器官的時(shí)鐘功能,。他們觀察了調(diào)控季節(jié)性繁殖的已知基因的表達(dá)以及與那些在眼睛中或松果腺中所發(fā)現(xiàn)的光受體相似的已知的光受體,。他們還發(fā)現(xiàn)，孤立的“血管囊”會(huì)對(duì)光的變化做出反應(yīng),，而且沒有“血管囊”的魚會(huì)失去它們對(duì)光的變化做出反應(yīng)的能力,。（生物谷Bioon.com）
生物谷推薦英文摘要：
Nature Communications doi:10.1038/ncomms3108
The saccus vasculosus of fish is a sensor of seasonal changes in day length
Yusuke Nakane, Keisuke Ikegami, Masayuki Iigo, Hiroko Ono, Korenori Takeda, Daisuke Takahashi, Maiko Uesaka, Meita Kimijima, Ramu Hashimoto, Natsumi Arai, Takuya Suga, Katsuya Kosuge, Tomotaka Abe, Ryosuke Maeda, Takumi Senga, Noriko Amiya, Teruo Azuma, Masafumi Amano, Hideki Abe, Naoyuki Yamamoto et al.
The pars tuberalis of the pituitary gland is the regulatory hub for seasonal reproduction in birds and mammals. Although fish also exhibit robust seasonal responses, they do not possess an anatomically distinct pars tuberalis. Here we report that the saccus vasculosus of fish is a seasonal sensor. We observe expression of key genes regulating seasonal reproduction and rhodopsin family genes in the saccus vasculosus of masu salmon. Immunohistochemical studies demonstrate that all of these genes are expressed in the coronet cells of the saccus vasculosus, suggesting the existence of a photoperiodic signalling pathway from light input to neuroendocrine output. In addition, isolated saccus vasculosus has the capacity to respond to photoperiodic signals, and its removal abolishes photoperiodic response of the gonad. Although the physiological role of the saccus vasculosus has been a mystery for several centuries, our findings indicate that the saccus vasculosus acts as a sensor of seasonal changes in day length in fish.
