Document Detail


The Importance of Perivitelline Fluid Convection to Oxygen Uptake of Pseudophryne bibronii Eggs.
MedLine Citation:
PMID:  21527821     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
Abstract The ciliated epithelium of amphibian embryos produces a current within the perivitelline fluid of the egg that is important in the convective transfer of oxygen to the embryo's surface. The effects of convection on oxygen uptake and the immediate oxygen environment of the embryo were investigated in Pseudophryne bibronii. Gelatin was injected into the eggs, setting the perivitelline fluid and preventing convective flow. Oxygen consumption rate ([Formula: see text]) and the oxygen partial pressure (Po(2)) of the perivitelline fluid were measured in eggs with and without this treatment. [Formula: see text] decreased in eggs without convection at Gosner stages 17-19 under normoxia. The lack of convection also shifted embryos from regulators to conformers as environmental Po(2) decreased. A strong Po(2) gradient formed within the eggs when convection was absent, demonstrating that the loss of convection is equivalent to decreasing the inner radius of the capsule, an important factor in gas exchange, by 25%. [Formula: see text] also declined in stage 26-27 embryos without cilia-driven convection, although not to the extent of younger stages, because of muscular movements and a greater skin surface area in direct contact with the inner capsule wall. This study demonstrates the importance of convective flow within the perivitelline fluid to gas exchange. Convection is especially important in the middle of embryonic development, when the perivitelline space has formed, creating a barrier to gas exchange, but the embryos have yet to develop muscular movements or have a large surface area exposed directly to the jelly capsule.
Authors:
Casey A Mueller; Roger S Seymour
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Physiological and biochemical zoology : PBZ     Volume:  84     ISSN:  1537-5293     ISO Abbreviation:  Physiol. Biochem. Zool.     Publication Date:    2011 May-Jun
Date Detail:
Created Date:  2011-04-29     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  100883369     Medline TA:  Physiol Biochem Zool     Country:  United States    
Other Details:
Languages:  eng     Pagination:  299-305     Citation Subset:  IM    
Affiliation:
Ecology and Evolutionary Biology, University of Adelaide, Adelaide, South Australia 5005, Australia.
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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