Document Detail


Differential ammonia metabolism in Aedes aegypti fat body and midgut tissues.
MedLine Citation:
PMID:  20206632     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In order to understand at the tissue level how Aedes aegypti copes with toxic ammonia concentrations that result from the rapid metabolism of blood meal proteins, we investigated the incorporation of (15)N from (15)NH(4)Cl into amino acids using an in vitro tissue culture system. Fat body or midgut tissues from female mosquitoes were incubated in an Aedes saline solution supplemented with glucose and (15)NH(4)Cl for 10-40min. The media were then mixed with deuterium-labeled amino acids, dried and derivatized. The (15)N-labeled and unlabeled amino acids in each sample were quantified by mass spectrometry techniques. The results demonstrate that both tissues efficiently incorporate ammonia into amino acids, however, the specific metabolic pathways are distinct. In the fat body, the (15)N from (15)NH(4)Cl is first incorporated into the amide side chain of Gln and then into the amino group of Gln, Glu, Ala and Pro. This process mainly occurs via the glutamine synthetase (GS) and glutamate synthase (GltS) pathway. In contrast, (15)N in midgut is first incorporated into the amino group of Glu and Ala, and then into the amide side chain of Gln. Interestingly, our data show that the GS/GltS pathway is not functional in the midgut. Instead, midgut cells detoxify ammonia by glutamate dehydrogenase, alanine aminotransferase and GS. These data provide new insights into ammonia metabolism in A. aegypti mosquitoes.
Authors:
Patricia Y Scaraffia; Qingfen Zhang; Kelsey Thorson; Vicki H Wysocki; Roger L Miesfeld
Publication Detail:
Type:  In Vitro; Journal Article; Research Support, N.I.H., Extramural     Date:  2010-03-12
Journal Detail:
Title:  Journal of insect physiology     Volume:  56     ISSN:  1879-1611     ISO Abbreviation:  J. Insect Physiol.     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-07-27     Completed Date:  2010-11-16     Revised Date:  2011-09-26    
Medline Journal Info:
Nlm Unique ID:  2985080R     Medline TA:  J Insect Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1040-9     Citation Subset:  IM    
Affiliation:
Department of Chemistry and Biochemistry, The University of Arizona, Tucson, AZ 85721-0088, USA. scaraffi@email.arizona.edu
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MeSH Terms
Descriptor/Qualifier:
Aedes / metabolism*
Alanine Transaminase / metabolism
Amino Acids / metabolism
Ammonia / metabolism*
Animals
Fat Body / metabolism*
Female
Gastrointestinal Tract / metabolism*
Glutamate Dehydrogenase / metabolism
Glutamate-Ammonia Ligase / metabolism
Mass Spectrometry
Metabolic Networks and Pathways / physiology*
Nitrogen Isotopes / metabolism
Grant Support
ID/Acronym/Agency:
GM-R01-051387/GM/NIGMS NIH HHS; R01 AI046541-10/AI/NIAID NIH HHS; R01AI046541/AI/NIAID NIH HHS
Chemical
Reg. No./Substance:
0/Amino Acids; 0/Nitrogen Isotopes; 7664-41-7/Ammonia; EC 1.4.1.2/Glutamate Dehydrogenase; EC 2.6.1.2/Alanine Transaminase; EC 6.3.1.2/Glutamate-Ammonia Ligase
Comments/Corrections

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


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