Document Detail


Symbiotic interaction between dinoflagellates and the demosponge Lubomirskia baicalensis: aquaporin-mediated glycerol transport.
MedLine Citation:
PMID:  19198776     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Lake Baikal is rich in endemic sponge species, among them the arborescently growing species Lubomirskia baicalensis. During winter when the lake is covered by ice, this species reproduces sexually, reflecting a high metabolic activity. Throughout the year, L. baicalensis lives in association with dinoflagellates, which - according to the data presented herein - are symbiotic. The dinoflagellates have been determined on the basis of their rDNA/ITS characteristics and were found to display high sequence similarity to Gymnodinium sanguineum. The dinoflagellates give the sponge its characteristic green color, reflecting the high chlorophyll content (chlorophyll-a content in March and September of 3.2 +/- 0.6 microg/g and 1.9 +/- 0.5 microg/g of protein, respectively). With the in vitro cell culture system for sponges, the primmorphs, it could be demonstrated that [(14)C] glycerol is readily taken up by sponge cells; this process can be inhibited by phloretin, an aquaporin channel blocker. In order to prove the effect of cholesterol on the intermediate metabolism of the sponge cells, molecule probes, cDNAs for key enzymes in gluconeogenesis, glycolysis, and citric acid, have been applied in Northern blot studies. The data revealed that the genes coding for the enzymes citrate synthase and fructose-1,6-bisphosphatase are strongly upregulated after exposure of primmorphs to glycerol. This effect is abolished by phloretin. The genes encoding the phosphoglucose isomerase and pyruvate dehydrogenase do not respond to glycerol supply, suggesting that their expression is not under genetic control in L. baicalensis. To prove the assumption that the aquaporin channel is involved in the influx of glycerol in sponge cells, this cDNA was cloned and applied for in situ hybridization studies. The results obtained show that cells surrounding the dinoflagellates become brightly stained after hybridization with the aquaporin this probe. This demonstrates that L. baicalensis cells respond to glycerol, a metabolite which might be supplied by the dinoflagellates and imported via the aquaporin channel into the sponge cells.
Authors:
Werner E G Müller; Sergey I Belikov; Oxana V Kaluzhnaya; L Chernogor; Anatoli Krasko; Heinz C Schröder
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Progress in molecular and subcellular biology     Volume:  47     ISSN:  0079-6484     ISO Abbreviation:  Prog. Mol. Subcell. Biol.     Publication Date:  2009  
Date Detail:
Created Date:  2009-02-09     Completed Date:  2009-05-21     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0233223     Medline TA:  Prog Mol Subcell Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  145-70     Citation Subset:  IM    
Affiliation:
Institute für Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universität, Mainz, Germany. wmueller@uni-mainz.de
Data Bank Information
Bank Name/Acc. No.:
GENBANK/AZ231299;  AZ231309
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MeSH Terms
Descriptor/Qualifier:
Animals
Aquaporins / metabolism*
Base Sequence
Chlorophyll / analysis
DNA, Ribosomal / genetics
Dinoflagellida / physiology*
Glycerol / metabolism*
Molecular Sequence Data
Phylogeny
Porifera / metabolism,  parasitology*
Seasons
Sequence Alignment
Symbiosis / physiology*
Chemical
Reg. No./Substance:
0/Aquaporins; 0/DNA, Ribosomal; 1406-65-1/Chlorophyll; 56-81-5/Glycerol

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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