Filamentous proteophosphoglycan secreted by Leishmania promastigotes forms gel-like three-dimensional networks that obstruct the digestive tract of infected sandfly vectors
Details
Publication Year 1999-10,Volume 78,Issue #10,Page 675-689
Journal Title
EUROPEAN JOURNAL OF CELL BIOLOGY
Publication Type
Journal Article
Abstract
Development of Leishmania parasites in the digestive tract of their sandfly vectors involves several morphological transformations from the intracellular mammalian amastigote via a succession of free and gut wall-attached promastigote stages to the infective metacyclic promastigotes. At the foregut midgut transition of Leishmania-infected sandflies a gel-like plug of unknown origin and composition is formed, which contains high numbers of parasites, that occludes the gut lumen and which may be responsible for the often observed inability of infected sandflies to draw blood. This "blocked fly" phenotype has been linked to efficient transmission of infectious metacyclic promastigotes from the vector to the mammalian host, We show by immunofluorescence and immunoelectron microscopy on two Leishmania/sandfly vector combinations (Leishmania mexicana/Lutzomyia longipalpis and L. major/Phlebotomus papatasi) that the gel-like mass is formed mainly by a parasite derived mucin-like filamentous proteophosphoglycan (fPPG) whereas the Leishmania polymeric secreted acid phosphatase (SAP) is not a major component of this plug. fPPG forms a dense three-dimensional network of filaments which engulf the promastigote cell bodies in a gellike mass. We propose that the continuous secretion of fPPG by promastigotes in the sandfly gut, that causes plug formation, is an important factor for the efficient transmission to the mammalian host.
Publisher
URBAN & FISCHER VERLAG
Keywords
ACID-PHOSPHATASE; PHLEBOTOMUS-PAPATASI; SURFACE LIPOPHOSPHOGLYCAN; LUTZOMYIA-LONGIPALPIS; MAJOR PROMASTIGOTES; PHOSPHOGLYCOPROTEIN POLYMER; PARASITE TRANSMISSION; ELECTRON-MICROSCOPY; MEXICANA; PSYCHODIDAE
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Creation Date: 1999-10-01 12:00:00
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