A brown algal sex pheromone reverses the sign of phototaxis by cAMP/Ca2+ dependent signaling in brown algal male gametes of Mutimo cylindricus (Cutleriaceae)
A brown algal sex pheromone reverses the sign of phototaxis by cAMP/Ca2+ dependent signaling in brown algal male gametes of Mutimo cylindricus (Cutleriaceae)
复制标题
褐藻性信息素通过 cAMP/Ca2 依赖性信号逆转 Mutimo cylindricus（Cutleriaceae）褐藻雄配子的趋光性迹象
DOI：
10.1016/j.jphotobiol.2019.01.010
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Kazuo Inaba
中科院分区：
文献类型：
--
作者：
Nana Kinoshita-Terauchi;Kogiku Shiba;Taiki Umezawa;Fuyuhiko Matsuda;Taizo Motomura;Kazuo Inaba
柱状褐藻的雄配子在海水中产卵后不久即表现出正趋光性，但随着时间的推移逐渐改变趋光性的标志。这种转化似乎需要细胞内钙离子浓度的降低。在这项研究中，我们发现，与雌配子混合，加速了雄配子趋光标志由正向负的转换。雌配子悬浮液离心后的上清液显示出相同的改变趋光性标志的活性，这表明雌配子释放的一个因子负责这一反应。一种已知的褐藻性信息素，外卡宾，诱导雄配子的趋化。圆柱体。这种化合物的加入引起了趋光性信号的变化，清楚地表明性信息素是逆转所必需的。磷酸二酯酶抑制剂茶碱可通过雌配子和外卡宾释放的因子抑制趋化性和趋光性符号的逆转。环核苷酸测定表明，细胞内cAMP浓度的增加与趋光性信号的变化是平行的，而不是cGMP。低钙海水中未观察到茶碱对趋光性信号的抑制作用。这些结果表明，cAMP和Ca~(2+)浓度介导的信号通路驱动着雄配子趋光性和趋化性两种重要行为之间的相互转化。
Male gametes of the brown algaMutimo cylindricusshow positive phototaxis soon after spawning in seawater but gradually change the sign of phototaxis with time. This conversion appears to need the decrease of intracellular Ca2+concentration. In this study, we revealed that the conversion of male gamete phototactic sign, positive to negative, was accelerated by mixing with female gametes. The supernatant after the centrifugation of female gamete suspension showed the same activity to change the phototactic sign, suggesting that a factor released from female gametes was responsible for the reaction. A known brown algal sex pheromone, ectocarpene, induced chemotaxis of male gametes ofM. cylindricus. The addition of this compound induced the change of phototactic sign, clearly indicating that a sex pheromone is essential for the reversal. An inhibitor of phosphodiesterase, theophylline, inhibited the chemotaxis and phototactic sign reversion by a factor released from female gametes and ectocarpene. Measurements of cyclic nucleotides showed that the increase in intracellular concentration of cAMP, not cGMP, was parallel to the change of phototactic sign. The inhibition of phototactic sign by theophylline was not observed in low Ca2+sea water. These results suggest that a signaling pathway mediated by cAMP and Ca2+concentrations drives the interconversion between two important behaviors of male gametes, phototaxis and chemotaxis.