Females of the brine shrimp Artemia franciscana produce either free-swimming nauplii via ovoviviparous pathway of reproduction or encysted embryos, known as cysts, via oviparous pathway, in which biological processes are arrested. While previous study has shown a crucial role of ATP-dependent molecular chaperone, heat shock protein 70 (Hsp70) in protecting A. franciscana nauplii against various abiotic and abiotic stressors, the function of this protein in diapausing embryos and cyst development, however, remains unknown. RNA interference (RNAi) was applied in this study to examine the role of Hsp70 in cyst development and stress tolerance, with the latter performed by desiccation and freezing, a common method used for diapause termination in Artemia cysts. Hsp70 knockdown was apparent in cysts released from females that were injected with Hsp70 dsRNA. The loss of Hsp70 affected neither the development nor morphology of the cysts. The time between fertilization and cyst release from Artemia females injected with Hsp70 dsRNA was delayed slightly, but the differences were not significant when compared to the controls. However, the hatching percentage of cysts which lacks Hsp70 were reduced following desiccation and freezing. Taken together, these results indicated that Hsp70 possibly plays a role in the stress tolerance but not in the development of diapause-destined embryos of Artemia. This research makes fundamental contributions to our understanding of the role molecular chaperone Hsp70 plays in Artemia, an excellent model organism for diapause studies of the crustaceans.

中文翻译：

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丰年虫中热激蛋白 70 敲低后的包囊活力和应激耐受性。


丰年虾的雌性通过卵胎生生殖途径产生自由游动的无节幼体，或通过卵生途径产生包囊胚胎，称为包囊，其中生物过程被抑制。虽然之前的研究表明 ATP 依赖性分子伴侣热休克蛋白 70 (Hsp70) 在保护 A. franciscana 无节幼体免受各种非生物和非生物应激源方面发挥着至关重要的作用，但该蛋白在滞育胚胎和囊肿发育中的功能仍然存在。未知。本研究应用RNA干扰（RNAi）来检查Hsp70在包囊发育和应激耐受中的作用，后者通过干燥和冷冻来进行，这是终止卤虫包囊滞育的常用方法。在注射 Hsp70 dsRNA 的雌性释放的囊肿中，Hsp70 敲低很明显。 Hsp70 的缺失既不影响包囊的发育也不影响其形态。注射Hsp70 dsRNA的丰年虫雌性的受精和囊肿释放之间的时间略有延迟，但与对照相比差异并不显着。然而，缺乏Hsp70的包囊的孵化率在干燥和冷冻后会降低。综上所述，这些结果表明 Hsp70 可能在胁迫耐受性中发挥作用，但在滞育胚胎的发育中不起作用。这项研究为我们了解分子伴侣 Hsp70 在卤虫中的作用做出了基础性贡献，卤虫是甲壳类滞育研究的优秀模式生物。