Document Detail

Bacterial infection changes the elemental composition of Daphnia magna.
MedLine Citation:
PMID:  18631369     Owner:  NLM     Status:  MEDLINE    
1. An animal's elemental composition can be an important indicator of its physiological state and role in ecosystem nutrient cycling. We examined the interactive effects of bacterial (Pasteuria ramosa) infection and phosphorus (P)-poor food on the body stoichiometry of Daphnia magna. Daphnia were exposed to or held free of a bacterial parasite and fed algal food of different C:P ratios (100-500) over a 28-day period. 2. To assess the effects of exposure and infection on Daphnia stoichiometry, we measured their whole body content of carbon (C), nitrogen (N), and P on four different days (4, 8, 15, and 28) during the experiment. 3. We found strong effects of infection, food quality, and/or their interactions on the C, N, and P content of Daphnia, especially as the infectious disease progressed. At the end of the experiment, infected animals had significantly more C and less P in their bodies than uninfected conspecifics. Body N content of Daphnia consuming P-rich food was reduced by bacterial infection whereas Daphnia consuming P-poor algae showed increased body N content from infection. 4. Using a mass-balance model, we found that changes in N and P content of host bodies were largely accountable by disease-induced alterations to Daphnia reproduction (i.e. bacterial induced sterility) and the accumulation of Pasteuria spores in the body cavity. Our calculations also show that the observed increase in host C content could not be accounted for by loss of eggs or accumulation of bacterial spores. This instead must result from unidentified changes to underlying daphnid tissue C content. 5. These results demonstrate that intraspecific variation in zooplankton body stoichiometry can be caused by exposure to and infection by bacterial parasites. In addition, these effects were found to depend both upon the stage of the disease and upon the food quality consumed by the host.
Paul C Frost; Dieter Ebert; Val H Smith
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2008-07-09
Journal Detail:
Title:  The Journal of animal ecology     Volume:  77     ISSN:  1365-2656     ISO Abbreviation:  J Anim Ecol     Publication Date:  2008 Nov 
Date Detail:
Created Date:  2009-01-23     Completed Date:  2009-03-19     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0376574     Medline TA:  J Anim Ecol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1265-72     Citation Subset:  IM    
Department of Biology, Trent University, Ontario, Canada.
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MeSH Terms
Body Composition / physiology*
Body Weight
Carbon / metabolism
Daphnia / microbiology*
Nitrogen / metabolism
Phosphorus / metabolism
Spores, Bacterial
Reg. No./Substance:
7440-44-0/Carbon; 7723-14-0/Phosphorus; 7727-37-9/Nitrogen

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

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