Document Detail


Uptake and cellular localization of exogenous lipids by Giardia lamblia, a primitive eukaryote.
MedLine Citation:
PMID:  9207743     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Giardia lamblia trophozoites are unable to carry out de novo lipid synthesis. It is therefore likely that lipids are acquired from the small intestine of the host, in which the trophozoites are exposed to free and conjugated fatty acids, various sterols, phospholipids, bile acids, and bile-lipid mixed micelles. Here we show that G. lamblia is capable of taking up exogenous phosphatidylcholine (PC), phosphatidylinositol (PI), sphingomyelin (SM), cholesterol, ceramide (Cer), and fatty acids. Results from epifluorescence and high-resolution confocal microscopy suggest that fluorescent analogs of SM and PC were accumulated in the plasma membranes, whereas palmitic acid and Cer were localized intracellularly. Interestingly, many of these analogs were also concentrated in perinuclear regions. Similar labeling patterns were observed when the fluorescent analogs were delivered to the parasite via liposomes. To test whether G. lamblia was capable of esterifying exogenous fatty acids into membrane or cellular phospholipids, trophozoites were pulse-labeled with 3H-labeled palmitic or myristic acids and the phospholipids analyzed by thin-layer chromatography. Results document that G. lamblia was able to incorporate exogenous fatty acids into various phospholipids, i.e., PI, PC, PE, and PG. Interestingly, a major portion of radiolabeled fatty acids was incorporated into PG, a phospholipid characteristic of prokaryotic membranes.
Authors:
T L Stevens; G R Gibson; R Adam; J Maier; M Allison-Ennis; S Das
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Experimental parasitology     Volume:  86     ISSN:  0014-4894     ISO Abbreviation:  Exp. Parasitol.     Publication Date:  1997 Jun 
Date Detail:
Created Date:  1997-07-14     Completed Date:  1997-07-14     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370713     Medline TA:  Exp Parasitol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  133-43     Citation Subset:  IM    
Affiliation:
Department of Biological Sciences, University of Texas, El Paso 79968-0519, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Esterification
Eukaryotic Cells / metabolism*
Fatty Acids / metabolism
Fluorescent Dyes
Giardia / metabolism*
Image Processing, Computer-Assisted
Lipid Metabolism*
Microscopy, Confocal
Microscopy, Fluorescence
Grant Support
ID/Acronym/Agency:
AI 136597/AI/NIAID NIH HHS; GM 08012/GM/NIGMS NIH HHS; RR 08124/RR/NCRR NIH HHS
Chemical
Reg. No./Substance:
0/Fatty Acids; 0/Fluorescent Dyes

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


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