Leishmania development in their vectors is closely connected with bloodmeal digestion. This thesis focuses on factors affecting bloodmeal digestion, egg development and Leishmania infection within the sand fly gut. First, we compared the effect of mammalian (rabbit) and avian (chicken) blood on digestion and eggs development in Phlebotomus duboscqi. Sand flies fed on chickens had twice lower protein concentrations in the midgut and significantly lower trypsin activity compared to those fed on rabbits. The highest differences in the trypsin activity were observed during first 24 hours post bloodmeal. In addition, females fed on chickens had slower eggs development and their eggs were 10 % smaller compared to those fed on rabbits. In the second part of the thesis we tested the effect of mosquito hormone TMOF on the trypsin activity and eggs development of Lutzomyia longipalpis. Rabbit blood with TMOF (28 mg/ml) was presented to the females via a membrane feeding system. Sand flies fed on blood with TMOF had 15 - 35 % less trypsin activity than control females fed on only rabbit blood. In addition, females fed on blood with TMOF had developed 30 % less eggs and their eggs were 12 - 24 % smaller compared to control group. However the effect of TMOF we observed was lower than that described previously...

Sand flies serve as the vectors of leishmaniasis and their saliva was shown to affect the outcome of Leishmania infection by immunomodulation of the host. On the other hand, sand fly saliva contains a large scale of farmacologically active proteins that are strongly immunogenous for bitten hosts and specific anti-saliva immunity initiated by repeated sand fly feeding provides protection against Leishmania infection. Specific cell-mediated immunity was shown to be the core of the protectivity; however, our data suggests that the protective immunity has certain limitations. In mice bitten by sand flies for prolonged periods, we observed the desenzitization in term of abrogation of the protective immunity. Thus, we can speculate that the protective effect of immunity is linked solely with the short-term exposure. Nevertheless, our experiments showed that this aspect is also conditioned by the immediate infection after the protective short-term immunization. Taken together, it seems that these limitations may explain the circulation of leishmaniasis in endemic areas, even though humans and animals are frequently immunized by bites of uninfected sand flies. Repeated sand fly feeding on various hosts also promotes production of anti-saliva antibodies that reflect the intensity of exposure. We...

The Leishmania spp. are kinetoplastid protozoan parasites that cause a spectrum of highly prevalent and neglected tropical diseases known as leishmaniasis. The parasites must undergo two life forms during their life cycle: the extracellular promastigote life stage within the sand fly vector, and the intracellular amastigote life stage after internalization of host phagocytic cells. In the extracellular life stage, Leishmania promastigotes reside and develop to their infectious metacyclic form solely in the gut lumen of the sand fly, a process known as metacyclogenesis. During this process, other organisms that co-inhabit the sand fly gut, collectively known as the microbiome, influence parasite development. Based on the hypothesis that vector gut microbiota influence the development of parasite virulence, we sequenced midgut microbiomes of the sand fly Lutzomyia longipalpis with or without L. infantum infection. Sucrose fed sand flies contained a highly diverse, stable midgut microbiome. Blood feeding caused a decrease in bacterial richness, which eventually recovered. However, bacterial richness progressively decreased in L. infantum-infected sand flies. Furthermore, parasites altered the relative abundance of several bacterial phylogenies, including Pseudomonas and Serratia. Importantly, antibiotic-mediated perturbation of the midgut microbiome rendered sand flies unable to support parasite growth and consequent development to infectious metacyclic forms, and revealing the level of microbial diversity may induce flies resistant to infection. Together, these data suggest the sand fly midgut microbiome is a critical factor for Leishmania growth and differentiation prior to disease transmission. During the intracellular amastigote life form, macrophages are the primary cell type to phagocytize parasites. The effect of secreted factors such as exosomes from Leishmania-infected human cells and their effect on the immune response has not been extensively investigated. In this thesis, we characterized the proteome of primary human donor monocyte-derived macrophage (MDM) exosomes during L. infantum infection compared to donor-matched uninfected controls, and determined their impact on naïve MDMs measured by cytokine gene expression and resistance to subsequent parasite infection. Proteomic comparisons of infected and uninfected MDM exosomes were made using stable isotopic dimethyl labeling LC-MS/MS technology. A total of 484 human proteins were identified between four donors. Proteins significantly less abundant in exosomes derived from infected MDMs were matrix metalloprotease 9, galectin-3 binding protein, and several Annexins and histone proteins. Proteins more abundant included galectin-1, galectin-9, and serotransferrin and transferrin receptor 1. Interestingly, class I and class II MHC protein chains were differentially abundant in our samples. Furthermore, we observed several Leishmania spp. proteins in exosomes from infected MDMs as well. Naïve MDMs pretreated with exosomes from infected or uninfected MDM for 4 hours were not more resistant to L. infantum infection nor displayed increased gene expression of the pro-inflammatory cytokines IL-1α, IL-1β, IL-6, IL-8 or TNF-α. To date, the work presented in this thesis is the first to comprehensively identify the proteome in primary human MDM exosomes during Leishmania spp. infection, and to determine the impact of these exosomes on the immune response of other naïve human MDMs.

<p>Leishmaniasis is a disease affecting more than 12 million people worldwide. It is caused by the protozoan parasite Leishmania, which is transmitted to humans and dog hosts through bites of infected sand flies belonging to genus Phlebotomine. Several studies have shown Polymerase Chain Reaction (PCR) to be effective for the diagnosis of VL in clinical samples compared to the classical methods. The aims of this study were first to compare four different sample preparation methods for the PCR diagnosis of visceral leishmaniasis (VL) using peripheral blood samples and furthermore to find a method that is sensitive, rapid, cost benefit, simple and easy to perform. Two preparation methods were compared for the isolation of leukocytes (with Ficoll and Tris –EDTA buffer) and two DNA isolation methods (with Proteinase K and QIAgen kit). From the methods that were compared, lysis of erythrocytes with TE and the QIAgen kit seems to be the most suitable to use.</p>

Leishmaniasis is a disease affecting more than 12 million people worldwide. It is caused by the protozoan parasite Leishmania, which is transmitted to humans and dog hosts through bites of infected sand flies belonging to genus Phlebotomine. Several studies have shown Polymerase Chain Reaction (PCR) to be effective for the diagnosis of VL in clinical samples compared to the classical methods. The aims of this study were first to compare four different sample preparation methods for the PCR diagnosis of visceral leishmaniasis (VL) using peripheral blood samples and furthermore to find a method that is sensitive, rapid, cost benefit, simple and easy to perform. Two preparation methods were compared for the isolation of leukocytes (with Ficoll and Tris –EDTA buffer) and two DNA isolation methods (with Proteinase K and QIAgen kit). From the methods that were compared, lysis of erythrocytes with TE and the QIAgen kit seems to be the most suitable to use.

Master of Science / Department of Entomology / Marcelo Ramalho-Ortigao / Sand flies (Diptera:Psychodidae) are vectors of parasites if the genus Leishmania, the causative agent of leishmaniasis, a neglected tropical disease in several countries around the world. Sand flies transmit Leishmania to suitable vertebrates during the blood meal and following a complex development parasites undergo within the fly. Many aspects of the Leishmania development within the sand fly vector are well known, however details about how sand fly molecules affect the parasite are still not yet known. Our group previously identified that RNAi knockdown of PpChit1, a midgut specific chitinase from the sand fly Phlebotomus papatasi, led to a significant decrease in the load of Le. major. In this study, we assessed potential fitness effects of antisera anti-PpChit1 on three laboratory-reared sand fly species (P. papatasi, Phlebotomus duboscqi, and Lutzomyia longipalpis). Our results suggest that feeding sand flies with anti-PpChit1 sera led to a one day delay in the onset of oviposition, and also suggested that anti-PpChit1-fed flies survived on average up to three days longer that control flies. Analyses of the peritrophic matrix (PM) indicated a significant increase in thickness 72 hours post anti-PpChit1 feeding compared to control sera. Altogether the results suggest that feeding sand flies with anti-PpChit1 likely affects the kinetics of sand PM, which in turn affects the flow of nutrients and certain aspects of sand fly fitness. In the course of this study, we also evaluated the ability of American Foxhounds naturally infected with Leishmania infantum to transmit these parasites via bites of phlebotomine sand flies to suitable vertebrates. Since 1999, an outbreak of canine visceral leishmaniasis (CVL) has been reported in the U.S especially among Foxhounds. The ability of sand flies to pick up and transmit this pathogen represents an important health risk for companion dogs and humans. Our results indicate that Foxhounds naturally infected with Le. infantum are highly infectious to sand flies and that the parasites are able to fully develop within these vectors and de successfully transmitted during blood feeding. Thus, the risk exists for these parasites to become endemic in North America where sand flies are also known to occur.

Master of Science / Department of Entomology / Marcelo Ramalho-Ortigao / Sand flies (Diptera:Psychodidae) are vectors of parasites of the genus Leishmania transmitted to suitable vertebrate host during blood feeding. For blood feeding arthropods, including sand flies, blood meal digestion requires the secretion of inhibitory molecules, such as Kazal-type serine proteinase inhibitors that are involved in preventing the blood from coagulating within the mouthparts and the midgut. Previous studies have identified such molecules in mosquitoes, ticks, and triatomine bugs. Following studies of the midgut transcriptome of Phlebotomus papatasi, the principal vector of Leishmania major, two non-classical Kazal-type serine proteinase inhibitors were identified (PpKzl1 and PpKzl2). We are interested in the role of these proteins as inhibitors of coagulation cascades, in addition to their potential effects on blood digestion in P. papatasi. Ppkzl1 is similar to thrombin and trypsin inhibitors in triatomines and mosquitoes and Ppkzl2 is similar to Kazal-type inhibitors in mosquitoes with unknown function. Analyses of expression profiles indicated that although both transcripts are expressed prior to blood feeding in the midgut of P. papatasi they are tightly regulated by the blood meal. Reverse genetics studies using RNAi-targeted knockdown of PpKzl1 and PpKzl2 by dsRNA injection did not result in a detectable effect on mRNA expression levels. Thus, we expressed a recombinant PpKzl2 in a mammalian expression system (CHO-S free style cells) that was applied to in vitro studies to assess activity against various serine proteinases. Recombinant PpKzl2 inhibited chymotrypsin at nanomolar levels and also inhibited thrombin and trypsin at micromolar levels, suggesting that native PpKzl2 is an active serine proteinase inhibitor and may regulate digestive enzymes and thrombin in the midgut. Leishmania development within the sand fly midgut is faced with several barriers that can severely impact the parasites. For transmission to occur, parasites must be able to overcome these barriers including digestive proteinases, escape from the peritrophic matrix, and midgut attachment. Early stages of Leishmania are susceptible to killing by digestive proteinases in the sand fly midgut. Thus, targeting serine proteinase inhibitors may provide a new strategy to prevent transmission of Leishmania.

Submitted by MARIA LUANA ALVES null (marialuana.alves@yahoo.com) on 2016-05-03T01:22:40Z No. of bitstreams: 1 Dissertacao prontissima.pdf: 2895955 bytes, checksum: be473eaface6279971e2b88213feefe9 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-05-04T20:03:51Z (GMT) No. of bitstreams: 1 alves_ml_me_ilha.pdf: 2895955 bytes, checksum: be473eaface6279971e2b88213feefe9 (MD5) / Made available in DSpace on 2016-05-04T20:03:51Z (GMT). No. of bitstreams: 1 alves_ml_me_ilha.pdf: 2895955 bytes, checksum: be473eaface6279971e2b88213feefe9 (MD5) Previous issue date: 2016-03-03 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A leishmaniose visceral (LV), doença causada pelo protozoário Leishmania infantum e transmitida pelo flebotomíneo Lutzomyia longipalpis, é considerada um problema de saúde pública no Brasil. O objetivo deste trabalho foi realizar um estudo epidemiológico sobre a ocorrência da LV em cães e gatos e de flebotomíneos em dois abrigos de animais, durante o período de um ano, no município de Ilha Solteira, SP. Amostras de material biológico foram coletadas de 192 cães e de 197 gatos, para realização de exames sorológicos por meio do ensaio imunoenzimático indireto (ELISA), da reação de imunofluorescência indireta (RIFI) para ambas espécies animais e da reação intradérmica de Montenegro para cães. Dos cães examinados, 17,2% (33/192) estavam sorologicamente positivos para LV pelo método ELISA, 19,8% (38/192) pela RIFI e 45,4% (15/33) pela reação intradérmica. Para cães, a concordância entre as técnicas sorológicas foi classificada de razoável a boa, mas quando comparadas à reação de Montenegro foi considerada ruim. No inquérito felino das 197 amostras, a soroprevalência foi de 32,4% (64/197) e 31,9% (63/197) no ELISA e RIFI, respectivamente. Embora a maioria dos cães e dos gatos entregue nos abrigos já estivesse infectada, seis cães e cinco gatos infectaram-se no interior desses abrigos, após algum tempo de permanência nesses recintos. Um total de 131 flebotomíneos foram capturados por meio das armadilhas luminosas, colocadas no interior dos dois abrigos durante o período de dois anos. Os fatores de riscos associados à LV foram determinados estatisticamente pela análise univariada, com valor significativo (p ≤ 0,05), onde o porte pequeno dos cães, o uso de coleira de deltametrina e o diagnóstico precoce foram variáveis determinantes que influenciaram a positividade dos animais, ou seja, as duas últimas variáveis determinaram significativamente na diminuição de casos positivos da doença nos abrigos. Concluiu-se que os animais desses abrigos estavam vulneráveis a essa parasitose por se tratarem de locais com a presença de flebotomíneos vetores e de animais positivos para LV, oferecendo risco para a disseminação da doença no município. / Visceral leishmaniasis (VL), a disease caused by Leishmania infantum and transmitted by the sand fly Lutzomyia longipalpis, is considered a public health problem in Brazil. The study aimed to carry out an epidemiological study on the occurrence of VL in dogs and cats, and sand flies during the period of one year in two animal shelters from Ilha Solteira, SP. A total of 197 and 192 biological material samples were collected, respectively from cats and dogs for serological survey by an indirect enzyme-linked immunosorbent assay (ELISA) and an indirect fluorescent antibody test (IFAT) for both species of animals, and the intradermal reaction of Montenegro (only for dogs). During the study with dogs, 17,2% (33/192) were serologically positive for LV by ELISA, 19,8% (38/192) by IFAT and 45,4% (15/33) by the intradermal method. The correlation analysis between the serological techniques was ranged from reasonable to good for dogs, but was bad when compared to the Montenegro reaction. The feline seroprevalence was 32,4% (64/197) and 31,9% (63/197) for ELISA and IFAT, respectively. Although the most of dogs and cats in shelters were infected, six dogs and five cats infected inside the shelters. A total of 131 sand flies were captured by the light traps in both shelters, during two years. The risk factors, statistically determined by univariate analysis (p ≤ 0.05), demonstrated that the small size of the dogs, the use of deltamethrin collar and the precocious diagnosis, significantly influenced the animals positivity for VL. It was concluded that these animal shelters were vulnerable to this parasitic infection because of the presence of sand flies and positive animals for LV. / FAPESP: 2014/12609-2

Phlebotomine sand flies (Diptera, Psychodidae) are small blood sucking insects which are only proven vectors of neglected tropical disease called leishmaniasis. Sand flies of the genus Phlebotomus act as vectors in the Old World and those of genus Lutzomyia are vectors in the New World. However, not all of them are capable of transmitting the disease. It is therefore crutial to conclusively determinate the species and have up-to-date knowledge of their natural occurence. Routine identification based on morphological characters is challenging due to intraspecific variability of these or their possible damage during the capture and preparation. In adition, correct assessment of distinctive cahracters, especially for females, is difficult and requires certain expertise. Thus, approaches of molecular taxonomy have been recently increasingly used for sand flies species determination. This thesis presents usage of DNA sequencing and MALDI-TOF protein profiling for routine determination of sand flies caught in southeastern Europe and adjacent regions, where we have lack of information of present sand flies species. Another part of this thesis focus on closer examination of relations between selected closely related species within species complexes. Key words: Phlebotomus, molacular identification, DNA...

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