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卵子发生在生物体形成过程中非常重要，影响到胚胎的发育以及个体的形成，在这个过程中，H+动力学起到一个关键的调节作用，细胞通过H+转运维持膜电势和产生跨膜的化学梯度来驱动次级代谢，但是在昆虫滋养型卵母细胞成卵过程中发生的H+流的变化和H+流引起的pH值变化所起到的调节作用却了解很少。利用“非损伤微测技术”可实现对H+流在不同时间和空间的实时监测，从而揭示H+流在昆虫滋养型卵母细胞生成过程中所起到的调节作用。 美国Wadsworth中心神经系统失调研究实验室科学家Bjornsson C. S.等采用“非损伤微测技术”对红锥蝽（Rhodnius prolixus）在相同生长部位的不同生长阶段进行胞外H+流实时监测发现，卵黄生成中期卵巢管中分离相邻卵泡囊的主茎表现出显著的H+外流，而在卵黄生成后期H+外流减弱。H+外流的现象不仅在主茎生成之前已经产生，而且先于邻近卵泡囊的卵黄生成起始阶段。另外在生成绒毛膜的末端卵泡囊和卵泡囊排卵后也分别检测到了H+的外流现象，这揭示了躯体的卵泡上皮细胞控制着H+的外流。 |
 上图： 上图是通过非损伤微测技术在卵巢管不同部位不同生长时期检测到的H+流的变化情况。正值为外流，负值为内流。 | |||
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该研究通过非损伤微测技术检测昆虫成卵过程中H+流的变化，揭示了H+流在卵黄生成的起始阶段、内吞、卵泡细胞骨架动力学及滤泡反馈机制调节中的重要作用，跨膜H+流可促使胞内pH值的改变。这为昆虫成卵过程的机理研究提供了新颖的思路和方法。 | ||||
关键词：H+, 离子选择电极(ion-selective probe) , 卵子发生(oogenesis)
参考文献：Bjornsson CS, et al. The Journal of Experimental Biology,2004, 207, 2835-2844
Abstract:
The spatiotemporal dynamics of transmembrane hydrogen ion (H+) fluxes during oogenesis were investigated in the telotrophic ovarioles of the insect, Rhodnius prolixus. Although Rhodnius ovarioles possess exaggerated morphological and electrical polarity between nurse cells and oocytes, little is known about H+ changes during oogenesis, despite the regulatory role played by H+ and pH in many relevant cellular processes. A number of dynamic extracellular H+ fluxes were measured along Rhodnius ovarioles, representing an oogenesis cycle, using a non-invasive, self-referencing, H+-selective probe. The interfollicular stalk separating adjacent follicles exhibited prominent H+ efflux that peaked during midvitellogenesis and declined during late vitellogenesis. H+ efflux in this region preceded stalk formation and, importantly, preceded the onset of vitellogenesis in the adjacent posterior follicle. H+ efflux was also observed over the terminal follicle, where specialized regions of the chorion were forming, and was still detected around follicle cells after ovulation, indicating that the somatic follicular epithelium produced this flux. Transmembrane H+ fluxes may drive intracellular pH changes or may stabilize pHi in response to pH-altering events. H+ fluxes may play a role in processes that coincide spatially and temporally, including the onset of vitellogenesis, endocytosis, follicle cell cytoskeletal dynamics, and regulation of interfollicular feedback mechanisms.