Comparative genomics of Leishmania donovani progeny from genetic crosses in two sand fly species and impact on the diversity of diagnostic and vaccine candidates.

Sand fly transmitted Leishmania species are responsible for severe, wide ranging, visceral and cutaneous leishmaniases. Genetic exchange can occur among natural Leishmania populations and hybrids can now be produced experimentally, with limitations. Feeding Phlebotomus orientalis or Phlebotomus argentipes on two strains of Leishmania donovani yielded hybrid progeny, selected using double drug resistance and fluorescence markers.

Dynamics of transition dipole moment orientation in representative fluorescent proteins.

Molecules of fluorescent proteins (FPs) exhibit distinct optical directionality. This optical directionality is characterized by transition dipole moments (TDMs), and their orientation with respect to the molecular structures. Although our recent observations of FP crystals allowed us to determine the mean TDM directions with respect to the framework of representative FP molecules, the dynamics of TDM orientations within FP molecules remain to be ascertained.

Directionality of light absorption and emission in representative fluorescent proteins.

Fluorescent molecules are like antennas: The rate at which they absorb light depends on their orientation with respect to the incoming light wave, and the apparent intensity of their emission depends on their orientation with respect to the observer. However, the directions along which the most important fluorescent molecules in biology, fluorescent proteins (FPs), absorb and emit light are generally not known. Our optical and X-ray investigations of FP crystals have now allowed us to determine the molecular orientations of the excitation and emission transition dipole moments in the FPs mTurquoise2, eGFP, and mCherry, and the photoconvertible FP mEos4b.

Role for the flagellum attachment zone in Leishmania anterior cell tip morphogenesis.

The shape and form of the flagellated eukaryotic parasite Leishmania is sculpted to its ecological niches and needs to be transmitted to each generation with great fidelity. The shape of the Leishmania cell is defined by the sub-pellicular microtubule array and the positioning of the nucleus, kinetoplast and the flagellum within this array. The flagellum emerges from the anterior end of the cell body through an invagination of the cell body membrane called the flagellar pocket.

Comparative Study of Promastigote- and Amastigote-Initiated Infection of Leishmania infantum (Kinetoplastida: Trypanosomatidae) in Phlebotomus perniciosus (Diptera: Psychodidae) Conducted in Different Biosafety Level Laboratories.

Sand flies (Diptera: Psychodidae) are natural vectors of Leishmania. For the initiation of sand fly experimental infections either Leishmania amastigotes or promastigotes can be used. In order to obtain comparable results, it is necessary to adjust and standardize procedures.

Genetic dissection of a Leishmania flagellar proteome demonstrates requirement for directional motility in sand fly infections.

The protozoan parasite Leishmania possesses a single flagellum, which is remodelled during the parasite's life cycle from a long motile flagellum in promastigote forms in the sand fly to a short immotile flagellum in amastigotes residing in mammalian phagocytes. This study examined the protein composition and in vivo function of the promastigote flagellum. Protein mass spectrometry and label free protein enrichment testing of isolated flagella and deflagellated cell bodies defined a flagellar proteome for L.

flagellum attachment zone is critical for flagellar pocket shape, development in the sand fly, and pathogenicity in the host.

kinetoplastid parasites infect millions of people worldwide and have a distinct cellular architecture depending on location in the host or vector and specific pathogenicity functions. An invagination of the cell body membrane at the base of the flagellum, the flagellar pocket (FP), is an iconic kinetoplastid feature, and is central to processes that are critical for pathogenicity. The FP has a bulbous region posterior to the FP collar and a distal neck region where the FP membrane surrounds the flagellum more closely.

Refractoriness of Sergentomyia schwetzi to Leishmania spp. is mediated by the peritrophic matrix.

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.

Leishmania mortality in sand fly blood meal is not species-specific and does not result from direct effect of proteinases.

Background: Leishmania development in sand flies is confined to the alimentary tract and is closely connected with blood meal digestion. Previously, it has been published that activities of sand fly midgut proteases are harmful to Leishmania, especially to amastigote-promastigote transition forms. However, our experiments with various Leishmania-sand fly pairs gave quite opposite results.

Lipophosphoglycan polymorphisms do not affect Leishmania amazonensis development in the permissive vectors Lutzomyia migonei and Lutzomyia longipalpis.

Background: Lipophosphoglycan (LPG) is a dominant surface molecule of Leishmania promastigotes. Its species-specific polymorphisms are found mainly in the sugars that branch off the conserved Gal(β1,4)Man(α1)-PO backbone of repeat units. Leishmania amazonensis is one of the most important species causing human cutaneous leishmaniasis in the New World.

Leishmania donovani development in Phlebotomus argentipes: comparison of promastigote- and amastigote-initiated infections.

Leishmania parasites alternate in their life cycle between promastigote stages that develop in the gut of phlebotomine sand flies and amastigotes residing inside phagocytic cells of vertebrate hosts. For experimental infections of sand flies, promastigotes are frequently used as this way of infection is technically easier although ingestion of promastigotes by sand flies is unnatural. Here we aimed to answer a critical question, to what extent do promastigote-initiated experimental infections differ from those initiated with intracellular amastigotes.

Characterization of a midgut mucin-like glycoconjugate of Lutzomyia longipalpis with a potential role in Leishmania attachment.

Background: Leishmania parasites are transmitted by phlebotomine sand flies and a crucial step in their life-cycle is the binding to the sand fly midgut. Laboratory studies on sand fly competence to Leishmania parasites suggest that the sand flies fall into two groups: several species are termed "specific/restricted" vectors that support the development of one Leishmania species only, while the others belong to so-called "permissive" vectors susceptible to a wide range of Leishmania species. In a previous study we revealed a correlation between specificity vs permissivity of the vector and glycosylation of its midgut proteins.

Lutzomyia migonei is a permissive vector competent for Leishmania infantum.

Background: Leishmania infantum is the most widespread etiological agent of visceral leishmaniasis (VL) in the world, with significant mortality rates in human cases. In Latin America, this parasite is primarily transmitted by Lutzomyia longipalpis, but the role of Lutzomyia migonei as a potential vector for this protozoan has been discussed. Laboratory and field investigations have contributed to this hypothesis; however, proof of the vector competence of L.

Natural hybrid of Leishmania infantum/L. donovani: development in Phlebotomus tobbi, P. perniciosus and Lutzomyia longipalpis and comparison with non-hybrid strains differing in tissue tropism.

Background: Infection caused by parasites from L. donovani complex can manifest as a serious visceral disease or a self-healing milder cutaneous form. The different tropism and pathology in humans is caused by the interaction between parasites, host and vector determinants but the mechanisms are not well understood.

Leptomonas seymouri: Adaptations to the Dixenous Life Cycle Analyzed by Genome Sequencing, Transcriptome Profiling and Co-infection with Leishmania donovani.

The co-infection cases involving dixenous Leishmania spp. (mostly of the L. donovani complex) and presumably monoxenous trypanosomatids in immunocompromised mammalian hosts including humans are well documented.

Structural comparison of lipophosphoglycan from Leishmania turanica and L. major, two species transmitted by Phlebotomus papatasi.

The lipophosphoglycan (LPG) of Leishmania major has a major role in the attachment to Phlebotomus papatasi midgut. Here, we investigated the comparative structural features of LPG of L. turanica, another species transmitted by P.

Cutaneous leishmaniasis caused by Leishmania infantum transmitted by Phlebotomus tobbi.

Transmission of cutaneous leishmaniasis (CL) caused by Leishmania infantum was studied in South Anatolia, Turkey. Small, non-ulcerating lesions prevailed and patients were negative in rK39 tests for antibody detection for human visceral leishmaniasis (VL). The most abundant sand fly species, Phlebotomus tobbi, was found positive for Leishmania promastigotes with a prevalence of 1.

Leishmania in sand flies: comparison of quantitative polymerase chain reaction with other techniques to determine the intensity of infection.

Quantification of Leishmania parasites in the sand fly digestive tract is important for evaluation of vector competence. We compared quantitative polymerase chain reaction (Q-PCR) with two "traditional" methods, estimation in situ and direct counting with the aid of a hemocytometer, to evaluate their usefulness in different parasite-vector combinations. Phlebotomus duboscqi Neveu-Lemarie and Phlebotomus arabicus Theodor sand flies were infected with Leishmania major and Leishmania infantum, respectively, and different approaches were compared to determine the intensity of Leishmania infections before and after defecation of the bloodmeal (on days 2 and 8 postinfection, respectively).

Increased transmission potential of Leishmania major/Leishmania infantum hybrids.

Development of Leishmania infantum/Leishmania major hybrids was studied in two sand fly species. In Phlebotomus papatasi, which supported development of L. major but not L.

A lipophosphoglycan-independent development of Leishmania in permissive sand flies.

Leishmaniases are serious parasitic diseases the etiological organisms of which are transmitted by insect vectors, phlebotominae sand flies. Two sand fly species, Phlebotomus papatasi and P. sergenti, display remarkable specificity for Leishmania parasites they transmit in nature, but many others are broadly permissive to the development of different Leishmania species.