2010 年 9 巻 2 号 p. 90-97
Some organisms are able to survive to almost complete desiccation, entering a latent state known as anhydrobiosis. The sleeping chironomid (Polypedilum vanderplanki) lives in the semi-arid regions of Africa and its larvae can survive desiccation in an anhydrobiotic form during the dry season. In order to unveil the molecular mechanisms of this desiccation tolerance, an anhydrobiosis-related Expressed Sequence Tag (EST) database was obtained from the sequences of three cDNA libraries constructed from P. vanderplanki larvae after 0h, 12h and 36h of desiccation. ESTs were classified according to gene ontology categories, and putative expression patterns were deduced for all clusters on the basis of the number of clones in each library; expression patterns were confirmed by real-time PCR for selected genes. Results suggest that the oxidative stress response plays a central role in successful anhydrobiosis. Similarly, protein denaturation and aggregation may be prevented by marked up-regulation of heat shock proteins (Hsps) and of the late embryogenesis abundant (LEA) proteins, which are anhydrobiosis specific. A third major feature is the increase in trehalose synthesis and the expression of various transporter proteins allowing the distribution of trehalose and other solutes to all tissues.