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The role of promastigote secretory gel in the origin and transmission of the infective stage of Leishmania mexicana by the sandfly Lutzomyia longipalpis

Rogers, M E and Chance, M L and Bates, P A (2002) The role of promastigote secretory gel in the origin and transmission of the infective stage of Leishmania mexicana by the sandfly Lutzomyia longipalpis. Parasitology, 124 (5). pp. 495-507. ISSN 0031-1820

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    Abstract

    Transmission of leishmaniasis is effected by a specific developmental stage, the metacyclic promastigote. The precursors of metacyclic promastigotes were a distinct subpopulation of parasites, identified for the first time as a new stage in the life-cycle and named leptomonad promastigotes. Microdissection of infected sandflies into 4 midgut regions and foregut allowed precursor-product relationships to be established for amastigote-procyclic promastigote, procyclic-nectomonad promastigote, nectomonad-leptomonad promastigote and leptomonad-metacyclic promastigote developmental switches. Metacyclic promastigotes occurred mainly in the thoracic midgut and cardia, coincident with the accumulation of a promastigote secretory gel (PSG) plug in these anterior regions. The gel-like plug was isolated from flies with mature infections and found to contain predominantly leptomonad promastigotes. The PSG plug also contained the majority (75%) of the total metacyclic promastigote population in the sandflies, which were concentrated at the anterior pole. The PSG plug was found to be the main site of metacyclogenesis, and acted as a reservoir of leptomonad promastigotes from which metacyclic forms differentiated and migrated forward to promote the infective potential of the fly. The PSG plug occluded and distorted the midgut, forcing the stomodeal valve open and affecting the feeding success of the sandflies, such that they experienced difficulty in taking a full meal. Collectively, these data support the role of the PSG in the transmission of leishmaniasis, by conditioning the midgut environment for metacyclogenesis and altering the feeding ability of infected sandflies.

    Item Type: Article
    Journal or Publication Title: Parasitology
    Additional Information: http://journals.cambridge.org/action/displayJournal?jid=PAR The final, definitive version of this article has been published in the Journal, Parasitology, 124 (5), pp 495-507 2002, © 2002 Cambridge University Press.
    Uncontrolled Keywords: Leishmania ; sandfly ; metacyclic promastigote ; promastigote secretory gel (PSG) ; transmission
    Subjects: Q Science > QR Microbiology > QR355 Virology
    Departments: Faculty of Health and Medicine > Biomedical & Life Sciences
    ID Code: 56027
    Deposited By: ep_importer_pure
    Deposited On: 20 Jul 2012 12:02
    Refereed?: Yes
    Published?: Published
    Last Modified: 26 Jul 2012 20:45
    Identification Number:
    URI: http://eprints.lancs.ac.uk/id/eprint/56027

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