Graduate School of Science, Osaka City University, Osaka, Japan.
Department of Biology, Miami University, Oxford, OH, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2021 Jun;256:110928. doi: 10.1016/j.cbpa.2021.110928. Epub 2021 Feb 26.
Larvae of the Antarctic midge Belgica antarctica Jacobs (Diptera: Chironomidae) are highly tolerant of diverse environmental stresses, including freezing, severe desiccation, and osmotic extremes. Furthermore, dehydration confers subsequent desiccation and freeze tolerance. While a role for aquaporins-channels for water and other solutes-has been proposed in these dehydration processes, the types of aquaporins involved in dehydration-driven stress tolerance remain unknown. In the present study, we investigated expression of six aquaporins (Drip, Prip, Eglp1, Eglp2, Aqp12L, and Bib) in larvae of B. antarctica subjected to three different dehydration conditions: desiccation, cryoprotective dehydration, and osmotic dehydration. The expression of Drip and Prip was up-regulated under desiccation and cryoprotective dehydration, suggesting a role for these aquaporins in efficient water loss under these dehydration conditions. Conversely, expression of Drip and Prip was down-regulated under osmotic dehydration, suggesting that their expression is suppressed in larvae to combat dehydration. Larval water content was similarly decreased under all three dehydration conditions. Differences in responses of the aquaporins to the three forms of dehydration suggests distinct water management strategies associated with different forms of dehydration stress.
南极摇蚊 Belgica antarcticaJacobs（双翅目：摇蚊科）的幼虫对各种环境压力具有很强的耐受性，包括冷冻、严重干燥和渗透压极端。此外，脱水会赋予随后的干燥和抗冻能力。虽然水通道蛋白——用于水和其他溶质的通道——在这些脱水过程中被认为具有作用，但参与脱水驱动的应激耐受的水通道蛋白类型仍不清楚。在本研究中，我们研究了 B. antarctica 幼虫中六种水通道蛋白（Drip、Prip、Eglp1、Eglp2、Aqp12L 和 Bib）在三种不同脱水条件下的表达：干燥、冷冻保护脱水和渗透脱水。在干燥和冷冻保护脱水下，Drip 和 Prip 的表达上调，表明这些水通道蛋白在这些脱水条件下高效失水的作用。相反，在渗透脱水下，Drip 和 Prip 的表达下调，表明在幼虫中抑制它们的表达以对抗脱水。在所有三种脱水条件下，幼虫的含水量均相似降低。水通道蛋白对三种脱水形式的不同反应表明，与不同形式的脱水应激相关的水管理策略存在差异。
