Aquaporins play a role in desiccation and freeze tolerance in larvae of the goldenrod gall fly, Eurosta solidaginis.
Survival of freezing not only requires organisms to tolerate ice formation within their body, but also depends on the rapid redistribution of water and cryoprotective compounds between intra- and extracellular compartments. Aquaporins are transmembrane proteins that serve as the major pathway through which water and small uncharged solutes (e.g. glycerol) enter and leave the cell. Consequently, we examined freeze-tolerant larvae of the goldenrod gall fly, Eurosta solidaginis, to determine whether aquaporins are present and if their presence promotes freeze tolerance of specific tissues. Immunoblotting with mammalian anti-AQP2, -AQP3 and -AQP4 revealed corresponding aquaporin homologues in E. solidaginis, whose patterns of expression varied depending on acclimation temperature and desiccation treatment. To examine the role of aquaporins in freeze tolerance, we froze fat body, midgut and salivary gland tissues in the presence and absence of mercuric chloride, an aquaporin inhibitor. Survival of fat body and midgut cells was significantly reduced when mercuric chloride was present. In contrast, survival of the salivary gland did not decrease when it was frozen with mercuric chloride. Overall, this study supports our hypothesis that naturally occurring aquaporins in E. solidaginis are regulated during desiccation and promote cell survival during freezing.
Philip
Benjamin N
BN
Department of Zoology, Miami University, Oxford, OH 45056, USA. philipbn@muohio.edu
Yi
Shu-Xia
SX
Elnitsky
Michael A
MA
Lee
Richard E
RE
D000222:Adaptation, Physiological / Q000187:drug effects; D000818:Animals; D020346:Aquaporins / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D001391:Azo Compounds; D002457:Cell Extracts; D003681:Dehydration / Q000378:metabolism*; D003890:Desiccation; D005216:Fat Body / Q000166:cytology / Q000187:drug effects; D005615:Freezing; D041981:Gastrointestinal Tract / Q000166:cytology / Q000187:drug effects; D007814:Larva / Q000187:drug effects / Q000502:physiology; D008627:Mercuric Chloride / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D012469:Salivary Glands / Q000166:cytology / Q000187:drug effects; D036624:Solidago / Q000187:drug effects / Q000469:parasitology*; D033621:Tephritidae / Q000187:drug effects / Q000502:physiology*; D014022:Tissue Survival / Q000187:drug effects
D020346:Aquaporins; D001391:Azo Compounds; D002457:Cell Extracts; D008627:Mercuric Chloride; C032756:ponceau S