Acquisition of freeze protection in a sea-ice crustacean through horizontal gene transfer?.

Kiko, Rainer (2010) Acquisition of freeze protection in a sea-ice crustacean through horizontal gene transfer?. Polar Biology, 33 . pp. 543-556. DOI 10.1007/s00300-009-0732-0.

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Sea ice is permeated by small brine channels, which are characterised by sub-zero temperatures and varying salinities. Despite sometimes extreme conditions a diverse fauna and Xora thrives within the brine channels.
The dominant calanoid copepods of Antarctic sea ice are
Stephos longipes and Paralabidocera antarctica. Here, I
report for the Wrst time thermal hysteresis (TH) in the haemolymph of a crustacean, S. longipes, whereas P. antarctica has no such activity. TH, the non-colligative
prevention of ice growth, seems to enable S. longipes to
exploit all available microhabitats within sea ice, especially the surface layer, in which strong temperature Xuctuations can occur. In contrast, P. antarctica only thrives within the lowermost centimetres of sea ice, where temperature Xuctuations are moderate. S. longipes possesses two isoforms of a protein with TH activity. A high homology to a group of (putative) antifreeze proteins from diatoms, bacteria and a snow mold and, in contrast, no homologs in any metazoan lineage suggest that this protein was obtained through horizontal gene transfer (HGT). Further analysis of available sequence data from sea-ice organisms indicates that these antifreeze proteins were probably transferred horizontally several times. Temperature and salinity Xuctuations within the brine channel system are proposed to provide “natural transformation” conditions enabling HGT and thus making this habitat a potential “hot spot” for HGT.

Document Type: Article
Keywords: Marine Biology; Sympagic meiofauna; Antifreeze protein; Ice binding protein; In situ hybridization; Stephos longipes; Paralabidocera antarctica; Lateral gene transfer
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-B Experimental Ecology - Benthic Ecology
Refereed: Yes
Open Access Journal?: No
Publisher: Springer
Date Deposited: 16 Mar 2010 12:45
Last Modified: 31 Jul 2019 09:24

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