BACKGROUND: Sand flies are vectors of Leishmania spp., the causative agents of leishmaniasis in vertebrates, including man. The sand fly saliva contains powerful pharmacologically active substances that prevent hemostasis and enhance Leishmania spp. infections. On the other hand, salivary proteins can protect vaccinated mice challenged with parasites. Therefore, sand fly salivary proteins are relevant for the epidemiology of leishmaniasis and can be a potential target for a vaccine against leishmaniasis. Despite this, studies on sand fly salivary glands (SGs) are limited. METHODS: The present study analyzes, in detail, the morphology, anatomy and ultrastructure of the SGs of sand fly vectors of the genera Lutzomyia and Phlebotomus. We used histology, transmission and scanning electron microscopy and lectin labeling associated with confocal laser microscopy. RESULTS: The SGs have conserved and distinct morphological aspects according to the distinct sand fly species. Each SG has a single rounded lobe constituting of c.100-120 secretory cells. The SG secretory cells, according to their ultrastructure and lectin binding, were classified into five different subpopulations, which may differ in secretory pathways. CONCLUSIONS: To the best of our knowledge, these morphological details of sand fly salivary glands are described for the first time. Further studies are necessary to better understand the role of these different cell types and better relate them with the production and secretion of the saliva substances, which has a fundamental role in the interaction of the sand fly vectors with Leishmania.
- MeSH
- elektronová mikroskopie MeSH
- infekce přenášené vektorem MeSH
- komáří přenašeči anatomie a histologie parazitologie ultrastruktura MeSH
- leishmanióza přenos MeSH
- Phlebotomus anatomie a histologie parazitologie ultrastruktura MeSH
- Psychodidae anatomie a histologie parazitologie ultrastruktura MeSH
- slinné žlázy parazitologie ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
BACKGROUND: The peritrophic matrix (PM) is an acellular chitin-containing envelope which in most blood sucking insects encloses the ingested blood meal and protects the midgut epithelium. Type I PM present in sand flies and other blood sucking batch feeders is secreted around the meal by the entire midgut in response to feeding. Here we tested the hypothesis that in Sergentomyia schwetzi the PM creates a physical barrier that prevents escape of Leishmania parasites from the endoperitrophic space. METHODOLOGY/PRINCIPAL FINDINGS: Morphology and ultrastructure of the PM as well the production of endogenous chitinase in S. schwetzi were compared with three sand fly species, which are natural vectors of Leishmania. Long persistence of the PM in S. schwetzi was not accompanied by different morphology or decreased production of chitinase. To confirm the role of the PM in refractoriness of S. schwetzi to Leishmania parasites, culture supernatant from the fungus Beauveria bassiana containing chitinase was added to the infective bloodmeal to disintegrate the PM artificially. In females treated with B. bassiana culture supernatants the PM was weakened and permeable, lacking multilayered inner structure; Leishmania colonized the midgut and the stomodeal valve and produced metacyclic forms. In control females Leishmania infections were lost during defecation. CONCLUSIONS/SIGNIFICANCE: Persistence of the PM till defecation of the bloodmeal represents an important factor responsible for refractoriness of S. schwetzi to Leishmania development. Leishmania major as well as L. donovani promastigotes survived defecation and developed late-stage infections only in females with PM disintegrated artificially by B. bassiana culture supernatants containing exogenous chitinase.
- MeSH
- hmyz - vektory parazitologie fyziologie ultrastruktura MeSH
- králíci MeSH
- Leishmania major fyziologie MeSH
- Psychodidae parazitologie fyziologie ultrastruktura MeSH
- trávicí systém parazitologie ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- chitin metabolismus MeSH
- Culex parazitologie ultrastruktura MeSH
- finanční podpora výzkumu jako téma MeSH
- hmyz - vektory parazitologie ultrastruktura MeSH
- leishmanióza kožní přenos MeSH
- Psychodidae parazitologie ultrastruktura MeSH
- trypanozomiáza přenos MeSH
- zvířata MeSH
- Check Tag
- ženské pohlaví MeSH
- zvířata MeSH
