鲤性腺GnRH-GtH旁分泌系统的发现及其在生长/生殖调控中的作用

鱼类生长与生殖间存在复杂的网络调控关系,本研究以黄河鲤(Cyprinus carpio)和转草鱼(Ctenopharyngodon idellus)生长激素基因(growth hormone, gh)鲤为研究对象,采用荧光定量PCR、免疫荧光、原位杂交及体外孵育实验等方法,探索了鲤性腺水平的生殖调控及其与生长的关系。发现鲤精巢和卵巢中存在促性腺激素α亚基(gonadotropin subunit alpha, gthα)、促卵泡激素β亚基(follicle stimulating hormone subunit beta, fshβ)、促黄体生成激素β亚基(luteinizing hormone subunit beta, lhβ)、促性腺激素释放激素3(gonadotropin-releasing hormone 3, gnrh3)、生长激素受体(growth hormone receptor, ghr)和4种GnRH受体mRNA。免疫荧光检测发现GTHα和LHβ主要定位在生殖细胞周围的体细胞和初级精母细胞中。进一步通过卵巢碎片体外GnRH孵育实验证实鲤性腺中存在独立于下丘脑-垂体-性腺轴的GnRH-GtH旁分泌系统。本研究还发现转gh鲤与对照鲤性腺中gnrh3及gthα、fshβ和lhβ的表达量存在显著差异,高浓度的GH促进处于初级生长期卵巢GnRH-GtH系统中gnrh3、gthα、fshβ和lhβ的转录,但抑制次级生长阶段卵巢中相应基因的转录。结果表明,鲤性腺中不仅存在GnRH-GtH旁分泌系统,并且在鲤的生长与生殖调控间扮演了重要角色,本研究为揭示鱼类生长与生殖间的调控机制积累了科学资料

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies