Document Detail

The effects of elevated osmotic concentration on control of germination in the gemmules of freshwater sponges Eunapius fragilis and Anheteromeyania ryderi.
MedLine Citation:
PMID:  19025500     Owner:  NLM     Status:  MEDLINE    
Freshwater sponges produce gemmules during the fall as an adaptation to survive cold winters. Most gemmules are produced in a state of diapause and must undergo a vernalization period before diapause is broken and they enter the quiescence state. Quiescent gemmules will germinate if placed at room temperature. We examined the mechanism of germination in two species of freshwater sponges, Eunapius fragilis and Anheteromeyania ryderi. Germination, cell division, and oxygen consumption are all inhibited when the osmotic concentration of the gemmules of either species is maintained at or above 50 mOsm by placing them in a solution of impermeable osmolytes. The internal osmotic concentration of cells of quiescent gemmules is maintained above 100 mOsm by the presence of sorbitol (in E. fragilis) and myoinositol (in A. ryderi). During the early stages of germination, levels of sorbitol and myoinositol decline to less than 50 mM by 20 h after the initiation of germination. The onset of cell division and beginning of germination correlate with the drop in osmolyte levels below 50 mOsm. Thus, an early trigger initiating germination is most likely the catabolism of sorbitol or myoinositol leading to a drop in the osmotic concentration of the cells.
Stephen H Loomis; Aubrey Bettridge; Bruce R Branchini
Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Physiological and biochemical zoology : PBZ     Volume:  82     ISSN:  1537-5293     ISO Abbreviation:  Physiol. Biochem. Zool.     Publication Date:    2009 Jul-Aug
Date Detail:
Created Date:  2009-05-27     Completed Date:  2009-08-25     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100883369     Medline TA:  Physiol Biochem Zool     Country:  United States    
Other Details:
Languages:  eng     Pagination:  388-95     Citation Subset:  IM    
Biology Department, Connecticut College, New London, 06320, USA.
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MeSH Terms
Cell Division / physiology
Fresh Water
Inositol / metabolism
Osmotic Pressure
Oxygen Consumption / physiology
Porifera / metabolism,  physiology*
Sorbitol / metabolism
Reg. No./Substance:
50-70-4/Sorbitol; 6917-35-7/Inositol

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

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