Trypanosoma Rangeli

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Patricia Azambuja - One of the best experts on this subject based on the ideXlab platform.

  • rhodnius prolixus interaction with Trypanosoma Rangeli modulation of the immune system and microbiota population
    Parasites & Vectors, 2015
    Co-Authors: Cecilia Stahl Vieira, Eloi S. Garcia, Daniele P. Castro, Marcela B. Figueiredo, Debora P Mattos, Peter J Waniek, Jayme M Santangelo, Marcia Gumiel, Fabio Faria Da Mota, Patricia Azambuja
    Abstract:

    Background Trypanosoma Rangeli is a protozoan that infects a variety of mammalian hosts, including humans. Its main insect vector is Rhodnius prolixus and is found in several Latin American countries. The R. prolixus vector competence depends on the T. Rangeli strain and the molecular interactions, as well as the insect’s immune responses in the gut and haemocoel. This work focuses on the modulation of the humoral immune responses of the midgut of R. prolixus infected with T. Rangeli Macias strain, considering the influence of the parasite on the intestinal microbiota.

  • parasite mediated interactions within the insect vector Trypanosoma Rangeli strategies
    Parasites & Vectors, 2012
    Co-Authors: Patricia Azambuja, Daniele P. Castro, Marcela B. Figueiredo, E S Garcia
    Abstract:

    Trypanosoma Rangeli is a protozoan that is non-pathogenic for humans and other mammals but causes pathology in the genus Rhodnius. T. Rangeli and R. prolixus is an excellent model for studying the parasite-vector interaction, but its cycle in invertebrates remains unclear. The vector becomes infected on ingesting blood containing parasites, which subsequently develop in the gut, hemolymph and salivary glands producing short and large epimastigotes and metacyclic trypomastigotes, which are the infective forms. The importance of the T. Rangeli cycle is the flagellate penetration into the gut cells and invasion of the salivary glands. The establishment of the parasite depends on the alteration of some vector defense mechanisms. Herein, we present our understanding of T. Rangeli infection on the vector physiology, including gut and salivary gland invasions, hemolymph reactions and behavior alteration.

  • Trypanosoma Rangeli: A new perspective for studying the modulation of immune reactions of Rhodnius prolixus
    Parasites and Vectors, 2009
    Co-Authors: Eloi S. Garcia, Fernando A. Genta, Daniele P. Castro, Marcela B. Figueiredo, Patricia Azambuja
    Abstract:

    ABSTRACT: Insects are exposed to a wide range of microorganisms (bacteria, fungi, parasites and viruses) and have interconnected powerful immune reactions. Although insects lack an acquired immune system they have well-developed innate immune defences that allow a general and rapid response to infectious agents.Over the last few decades we have observed a dramatic increase in the knowledge of insect innate immunity, which relies on both humoral and cellular responses. However, innate reactions to natural insect pathogens and insect-transmitted pathogens, such as parasites, still remain poorly understood.In this review, we briefly introduce the general immune system of insects and highlight our current knowledge of these reactions focusing on the interactions of Trypanosoma Rangeli with Rhodnius prolixus, an important model for innate immunity investigation.

  • Trypanosoma Rangeli interactions within the vector Rhodnius prolixus - A mini review
    Memorias do Instituto Oswaldo Cruz, 2005
    Co-Authors: Patricia Azambuja, Eloi S. Garcia
    Abstract:

    This article is an integrative mini review of the research on the interactions between Trypanosoma Rangeli and the insect vector, Rhodnius prolixus. Special attention is given to the interactions of these parasites with the gut environment, gut walls, with hemolymph invasion, hemocytes, hemocyte microaggregations, prophenoloxidase-activating system, superoxide, and nitric acid generation and eicosanoid pathways. We described factors affecting vectorial capacity and suggested that T. Rangeli may modulate the hemocoelic invasion and the survival of the parasites by overcoming the cellular and humoral defense reactions of the insect vector at different physiological events. The mechanisms of these interactions and their significance for parasite transmission are discussed.

  • inhibition of hemocyte microaggregation reactions in rhodnius prolixus larvae orally infected with Trypanosoma Rangeli
    Experimental Parasitology, 2004
    Co-Authors: Eloi S. Garcia, Evandro M.m. Machado, Patricia Azambuja
    Abstract:

    Hemocoelic inoculation of epimastigotes of Trypanosoma Rangeli strain H14 into 5th-instar larvae of Rhodnius prolixus previously fed on blood containing the same parasites, showed reduced number of hemocyte microaggregates in the hemolymph, enhanced number of flagellates in the hemolymph as well as increased mortality of these insects. All these effects were counteracted by combined inoculation of R. prolixus with T. Rangeli and arachidonic acid. In vitro assays using hemolymph taken from insects previously fed on blood containing parasites showed that hemocyte microaggregation reactions were also attenuated when T. Rangeli is used as inducer of the reaction, and that simultaneous applying T. Rangeli with arachidonic counteracted the hemocyte microaggregation inhibition. We suggest that arachidonic acid pathway can be a mediator of hemocyte microaggregation reactions in the hemolymph of insects inoculated with T. Rangeli, and that oral infection with this protozoan inhibits the release of arachidonic acid.

Edmundo C Grisard - One of the best experts on this subject based on the ideXlab platform.

  • Cytochrome oxidase subunit 2 gene allows simultaneous detection and typing of Trypanosoma Rangeli and Trypanosoma cruzi
    Parasites & Vectors, 2013
    Co-Authors: Mario Steindel, Edmundo C Grisard, Lara Maria Kalempa Demeu, Débora Denardin Lückemeyer, Quirino Alves De Lima Neto, Silvana Marques De Araújo, Max Jean De Ornelas Toledo, Mônica Lúcia Gomes
    Abstract:

    Background The parasites Trypanosoma Rangeli and Trypanosoma cruzi share vectors and hosts over a wide geographical area in Latin America. In this study, we propose a single molecular approach for simultaneous detection and typing of T. Rangeli and T. cruzi.

  • Trypanosoma Rangeli protein tyrosine phosphatase is associated with the parasite's flagellum
    Memorias Do Instituto Oswaldo Cruz, 2012
    Co-Authors: Elisa Beatriz Prestes, Mario Steindel, Patricia Hermes Stoco, Thais Cristine Marques Sincero, Stenio Perdigao Fragoso, Ethel Bayer-santos, Glauber Wagner, Adriana Castilhos Souza Umaki, Juliano Bordignon, Edmundo C Grisard
    Abstract:

    Protein tyrosine phosphatases (PTPs) play an essential role in the regulation of cell differentiation in pathogenic Trypanosomatids. In this study, we describe a PTP expressed by the non-pathogenic protozoan Trypanosoma Rangeli (TrPTP2). The gene for this PTP is orthologous to the T. brucei TbPTP1 and Trypanosoma cruzi (TcPTP2) genes. Cloning and expression of the TrPTP2 and TcPTP2 proteins allowed anti-PTP2 monoclonal antibodies to be generated in BALB/c mice. When expressed by T. Rangeli epimastigotes and trypomastigotes, native TrPTP2 is detected as a ~65 kDa protein associated with the parasite's flagellum. Given that the flagellum is an important structure for cell differentiation in Trypanosomatids, the presence of a protein responsible for tyrosine dephosphorylation in the T. Rangeli flagellum could represent an interesting mechanism of regulation in this structure.

  • Trypanosoma Rangeli expresses a β galactofuranosyl transferase
    Experimental Parasitology, 2012
    Co-Authors: Patricia Hermes Stoco, Mario Steindel, Débora Denardin Lückemeyer, Cassandra Aresi, Maisa M Sperandio, Thais Cristine Marques Sincero, Luiz Claudio Miletti, Edmundo C Grisard
    Abstract:

    Abstract Glycoconjugates play essential roles in cell recognition, infectivity and survival of protozoan parasites within their insect vectors and mammalian hosts. β-galactofuranose is a component of several glycoconjugates in many organisms, including a variety of Trypanosomatids, but is absent in mammalian and African trypanosomes. Herein, we describe the presence of a β(1–3) galactofuranosyl transferase (GALFT), an important enzyme of the galactofuranose biosynthetic pathway, in Trypanosoma Rangeli. The T. Rangeli GALFT gene (TrGALFT) has an ORF of 1.2 Kb and is organized in two copies in the T. Rangeli genome. Antibodies raised against an internal fragment of the transferase demonstrated a 45 kDa protein coded by TrGALFT was localized in the whole cytoplasm, mainly in the Golgi apparatus and equally expressed in epimastigotes and trypomastigotes from T. Rangeli. Despite the high sequence similarity with Trypanosoma cruzi and Leishmania spp. orthologous TrGALFT showed a substitution of the metal-binding DXD motif, conserved amongst glycosyltransferases, for a DXE functionally analogous motif. Moreover, a reduced number of GALFT genes were present in T. Rangeli when compared with other pathogenic kinetoplastid species.

  • transcriptomic analyses of the avirulent protozoan parasite Trypanosoma Rangeli
    Molecular and Biochemical Parasitology, 2010
    Co-Authors: Edmundo C Grisard, Patricia Hermes Stoco, Thais Cristine Marques Sincero, Cristiane Q Snoeijer, Glauber Wagner, Juliana B Rodrigues, Gianinna Rotava, Leonardo B Koerich
    Abstract:

    Abstract Two species of the genus Trypanosoma infective to humans have been extensively studied at a cell and molecular level, but study of the third, Trypanosoma Rangeli , remains in relative infancy. T. Rangeli is non-pathogenic, but is frequently mistaken for the related Chagas disease agent Trypanosoma cruzi with which it shares vectors, hosts, significant antigenicity and a sympatric distribution over a wide geographical area. In this study, we present the T. Rangeli gene expression profile as determined by the generation of ESTs (Expressed Sequence Tags) and ORESTES (Open Reading Frame ESTs). A total of 4208 unique high quality sequences were analyzed, composed from epimastigote and trypomastigote forms of SC-58 and Choachi strains, representing the two major phylogenetic lineages of this species. Comparative analyses with T. cruzi and other parasitic kinetoplastid species allowed the assignment of putative biological functions to most of the sequences generated and the establishment of an annotated T. Rangeli gene expression database. Even though T. Rangeli is apathogenic to mammals, genes associated with virulence in other pathogenic kinetoplastids were found. Transposable elements and genes associated mitochondrial gene expression, specifically RNA editing components, are also described for the first time. Our studies confirm the close phylogenetic relationship between T. cruzi and T. Rangeli and enable us to make an estimate for the size of the T. Rangeli genome repertoire (∼8500 genes) .

  • comparative analysis of Trypanosoma Rangeli histone h2a gene intergenic region with distinct intraspecific lineage markers
    Vector-borne and Zoonotic Diseases, 2009
    Co-Authors: Concepción J. Puerta, Patricia Hermes Stoco, Thais Cristine Marques Sincero, Claudia Cuervo, Edmundo C Grisard
    Abstract:

    Abstract This study shows the characterization of the histone H2A intergenic region sequences (H2A IR) from Trypanosoma Rangeli KP1(+) and KP1(−) strains isolated from distinct hosts and geographic regions. Also, a comparative unweighted pair-group method using arithmetic averages (UPMGA) analysis with polymerase chain reaction profiles of the 24Sα rDNA and the miniexon genes was performed. Detailed H2A IR sequence analysis revealed a discrete size polymorphism among T. Rangeli strains and the presence of single-nucleotide polymorphisms and minisatellite repeats, exclusively allowing an interspecific differentiation from T. cruzi strains representing the main parasite lineages. Differently from the H2A IR, UPMGA analysis of the 24Sα rDNA and the miniexon genes profiles clearly branched T. Rangeli strains into KP1(−) and KP1(+) lineages, clustering separately the Brazilian and Colombian KP1(−) strains. The evolutionary implications of these findings are discussed.

Mario Steindel - One of the best experts on this subject based on the ideXlab platform.

  • Cytochrome oxidase subunit 2 gene allows simultaneous detection and typing of Trypanosoma Rangeli and Trypanosoma cruzi
    Parasites & Vectors, 2013
    Co-Authors: Mario Steindel, Edmundo C Grisard, Lara Maria Kalempa Demeu, Débora Denardin Lückemeyer, Quirino Alves De Lima Neto, Silvana Marques De Araújo, Max Jean De Ornelas Toledo, Mônica Lúcia Gomes
    Abstract:

    Background The parasites Trypanosoma Rangeli and Trypanosoma cruzi share vectors and hosts over a wide geographical area in Latin America. In this study, we propose a single molecular approach for simultaneous detection and typing of T. Rangeli and T. cruzi.

  • Trypanosoma Rangeli protein tyrosine phosphatase is associated with the parasite's flagellum
    Memorias Do Instituto Oswaldo Cruz, 2012
    Co-Authors: Elisa Beatriz Prestes, Mario Steindel, Patricia Hermes Stoco, Thais Cristine Marques Sincero, Stenio Perdigao Fragoso, Ethel Bayer-santos, Glauber Wagner, Adriana Castilhos Souza Umaki, Juliano Bordignon, Edmundo C Grisard
    Abstract:

    Protein tyrosine phosphatases (PTPs) play an essential role in the regulation of cell differentiation in pathogenic Trypanosomatids. In this study, we describe a PTP expressed by the non-pathogenic protozoan Trypanosoma Rangeli (TrPTP2). The gene for this PTP is orthologous to the T. brucei TbPTP1 and Trypanosoma cruzi (TcPTP2) genes. Cloning and expression of the TrPTP2 and TcPTP2 proteins allowed anti-PTP2 monoclonal antibodies to be generated in BALB/c mice. When expressed by T. Rangeli epimastigotes and trypomastigotes, native TrPTP2 is detected as a ~65 kDa protein associated with the parasite's flagellum. Given that the flagellum is an important structure for cell differentiation in Trypanosomatids, the presence of a protein responsible for tyrosine dephosphorylation in the T. Rangeli flagellum could represent an interesting mechanism of regulation in this structure.

  • Trypanosoma Rangeli expresses a β galactofuranosyl transferase
    Experimental Parasitology, 2012
    Co-Authors: Patricia Hermes Stoco, Mario Steindel, Débora Denardin Lückemeyer, Cassandra Aresi, Maisa M Sperandio, Thais Cristine Marques Sincero, Luiz Claudio Miletti, Edmundo C Grisard
    Abstract:

    Abstract Glycoconjugates play essential roles in cell recognition, infectivity and survival of protozoan parasites within their insect vectors and mammalian hosts. β-galactofuranose is a component of several glycoconjugates in many organisms, including a variety of Trypanosomatids, but is absent in mammalian and African trypanosomes. Herein, we describe the presence of a β(1–3) galactofuranosyl transferase (GALFT), an important enzyme of the galactofuranose biosynthetic pathway, in Trypanosoma Rangeli. The T. Rangeli GALFT gene (TrGALFT) has an ORF of 1.2 Kb and is organized in two copies in the T. Rangeli genome. Antibodies raised against an internal fragment of the transferase demonstrated a 45 kDa protein coded by TrGALFT was localized in the whole cytoplasm, mainly in the Golgi apparatus and equally expressed in epimastigotes and trypomastigotes from T. Rangeli. Despite the high sequence similarity with Trypanosoma cruzi and Leishmania spp. orthologous TrGALFT showed a substitution of the metal-binding DXD motif, conserved amongst glycosyltransferases, for a DXE functionally analogous motif. Moreover, a reduced number of GALFT genes were present in T. Rangeli when compared with other pathogenic kinetoplastid species.

  • different serological cross reactivity of Trypanosoma Rangeli forms in Trypanosoma cruzi infected patients sera
    Parasites & Vectors, 2008
    Co-Authors: Milene Hoehr De Moraes, Mario Steindel, Alessandra A Guarneri, Fabiana P Girardi, Juliana B Rodrigues, Iriane Eger, Kevin M Tyler, Edmundo C Grisard
    Abstract:

    Background American Trypanosomiasis or Chagas disease is caused by Trypanosoma cruzi which currently infects approximately 16 million people in the Americas causing high morbidity and mortality. Diagnosis of American trypanosomiasis relies on serology, primarily using indirect immunofluorescence assay (IFA) with T. cruzi epimastigote forms. The closely related but nonpathogenic Trypanosoma Rangeli has a sympatric distribution with T. cruzi and is carried by the same vectors. As a result false positives are frequently generated. This confounding factor leads to increased diagnostic test costs and where false positives are not caught, endangers human health due to the toxicity of the drugs used to treat Chagas disease.

  • internal transcribed spacers its of Trypanosoma Rangeli ribosomal dna rdna a useful marker for inter specific differentiation
    Infection Genetics and Evolution, 2005
    Co-Authors: Ingrid Thais Beltramebotelho, Mario Steindel, D Gasparsilva, Alberto M R Davila, Edmundo C Grisard
    Abstract:

    Abstract The internal transcribed spacers (ITS) flanking the 5.8S subunit of the ribosomal RNA genes (rDNA) of Trypanosoma Rangeli strains isolated from distinct geographical regions and hosts were studied. The results revealed the sequence variability of the ITS spacers showing the presence of microsatellite repeats and single nucleotide polymorphisms (SNP), which were also observed within the 5.8S rDNA sequence. ITS-2 spacer was the most phylogenetically informative region due the presence of a higher number of parsimonious sites in both inter- and intra-specific analysis. Sequence analysis of both ITS spacers plus the 5.8S rDNA of T. Rangeli strains allowed a clear inter-specific differentiation from Trypanosoma cruzi strains representative of the parasite zymodemes.

Concepción J. Puerta - One of the best experts on this subject based on the ideXlab platform.

  • sequence polymorphism in the Trypanosoma Rangeli hsp70 coding genes allows typing of the parasite kp1 and kp1 groups
    Experimental Parasitology, 2013
    Co-Authors: Claudia Cuervo, M C Lopez, Carmen M Thomas, Concepción J. Puerta
    Abstract:

    Abstract The genes encoding the Trypanosoma Rangeli heat shock protein 70 kDa were sequenced and their genomic organization determined. This human parasite has medical relevance as it shares antigens, hosts and geographical regions with the etiological agent of Chagas’ disease, Trypanosoma cruzi. The T. Rangeli HSP70 genes are highly conserved regarding their tandem organization, and deduced amino acid sequences among T. Rangeli KP1(+) and KP1(−) groups and other Trypanosomatids. Nevertheless, a variable number of the immunogenic GMPG motif was observed among HSP70 copies within the same T. Rangeli isolate and among different isolates. Interestingly, a polymorphism at nucleotide level affecting the SphI restriction site allowed the differentiation of KP1(−) and KP1(+) groups.

  • Sequence polymorphism in the Trypanosoma Rangeli HSP70 coding genes allows typing of the parasite KP1(+) and KP1(−) groups
    Experimental Parasitology, 2013
    Co-Authors: Claudia Cuervo, Manuel Carlos López, M. Carmen Thomas, Concepción J. Puerta
    Abstract:

    Abstract The genes encoding the Trypanosoma Rangeli heat shock protein 70 kDa were sequenced and their genomic organization determined. This human parasite has medical relevance as it shares antigens, hosts and geographical regions with the etiological agent of Chagas’ disease, Trypanosoma cruzi. The T. Rangeli HSP70 genes are highly conserved regarding their tandem organization, and deduced amino acid sequences among T. Rangeli KP1(+) and KP1(−) groups and other Trypanosomatids. Nevertheless, a variable number of the immunogenic GMPG motif was observed among HSP70 copies within the same T. Rangeli isolate and among different isolates. Interestingly, a polymorphism at nucleotide level affecting the SphI restriction site allowed the differentiation of KP1(−) and KP1(+) groups.

  • comparative analysis of Trypanosoma Rangeli histone h2a gene intergenic region with distinct intraspecific lineage markers
    Vector-borne and Zoonotic Diseases, 2009
    Co-Authors: Concepción J. Puerta, Patricia Hermes Stoco, Thais Cristine Marques Sincero, Claudia Cuervo, Edmundo C Grisard
    Abstract:

    Abstract This study shows the characterization of the histone H2A intergenic region sequences (H2A IR) from Trypanosoma Rangeli KP1(+) and KP1(−) strains isolated from distinct hosts and geographic regions. Also, a comparative unweighted pair-group method using arithmetic averages (UPMGA) analysis with polymerase chain reaction profiles of the 24Sα rDNA and the miniexon genes was performed. Detailed H2A IR sequence analysis revealed a discrete size polymorphism among T. Rangeli strains and the presence of single-nucleotide polymorphisms and minisatellite repeats, exclusively allowing an interspecific differentiation from T. cruzi strains representing the main parasite lineages. Differently from the H2A IR, UPMGA analysis of the 24Sα rDNA and the miniexon genes profiles clearly branched T. Rangeli strains into KP1(−) and KP1(+) lineages, clustering separately the Brazilian and Colombian KP1(−) strains. The evolutionary implications of these findings are discussed.

  • Cellular location of KMP-11 protein in Trypanosoma Rangeli.
    Vector-borne and Zoonotic Diseases, 2008
    Co-Authors: Hugo Díez, Ladys Sarmiento, María Leonor Caldas, Marleny Montilla, María Del Carmen Thomas, Manuel Carlos López, Concepción J. Puerta
    Abstract:

    We describe the localization of the KMP-11 protein in the Trypanosoma Rangeli parasite determined by immunoelectron microscopy using a monoclonal antibody generated against the Trypanosoma cruzi KMP-11 protein. The data reported herein show that the T. Rangeli KMP-11 protein is mainly accumulated in the parasite cytoplasm, the coat, the flagellum, and the flagellar pocket. The high degree of sequence homology between the KMP-11 proteins from both parasites suggests that the KMP-11 protein from T. Rangeli, like that of T. cruzi, could also be associated with the parasite cytoskeleton.

  • the Trypanosoma Rangeli histone h2a gene sequence serves as a differential marker for kp1 strains
    Infection Genetics and Evolution, 2006
    Co-Authors: Claudia Cuervo, M C Lopez, Concepción J. Puerta
    Abstract:

    Abstract Trypanosoma Rangeli has recently been divided in two primary lineages denoted as KP1(+) and KP1(−) strains because of epidemiological and evolutionary interest in the molecular differentiation of these two groups. We report the molecular characterization of the genes encoding histone H2A protein from a T. Rangeli KP1(+) strain (H14), its comparison to T. Rangeli KP1(−) strain (C23) histone H2A coding genes [Puerta, C., Cuervo, P., Thomas, M.C., Lopez, M.C., 2000. Molecular characterization of the histone H2A gene from the parasite Trypanosoma Rangeli . Parasitol. Res. 86, 916–922], and its application in a low-stringency single specific primer polymerase chain reaction (LSSP-PCR) assay to differentiate these parasite groups. The results show that the locus encoding the H2A protein in the H14 strain is formed by at least 11 gene units measuring 799 nucleotides in length, organized in tandem, and located in two chromosomes of approximately 1.9 and 1.1 Mb in size. Remarkably, in KP1(−) strains these genes are on pairs of chromosomes of about 1.7 and 1.9 Mb. In addition, there is a hybridization signal in the compression region above 2.1 Mb in all T. Rangeli strains. Therefore, the chromosomal location of these genes is a useful marker to distinguish between KP1(+) and KP1(−) T. Rangeli strains. The alignment of the H2A nucleotide sequences from H14 and C23 strains showed an identity of 99.5% between the coding regions and an identity of 95% between the non-coding regions. The deduced amino acid sequences proved to be identical. Based on 5% of the difference between the intergenic regions, we developed a LSSP-PCR assay which can differentiate between KP1(+) and KP1(−) strains.

Eloi S. Garcia - One of the best experts on this subject based on the ideXlab platform.

  • rhodnius prolixus interaction with Trypanosoma Rangeli modulation of the immune system and microbiota population
    Parasites & Vectors, 2015
    Co-Authors: Cecilia Stahl Vieira, Eloi S. Garcia, Daniele P. Castro, Marcela B. Figueiredo, Debora P Mattos, Peter J Waniek, Jayme M Santangelo, Marcia Gumiel, Fabio Faria Da Mota, Patricia Azambuja
    Abstract:

    Background Trypanosoma Rangeli is a protozoan that infects a variety of mammalian hosts, including humans. Its main insect vector is Rhodnius prolixus and is found in several Latin American countries. The R. prolixus vector competence depends on the T. Rangeli strain and the molecular interactions, as well as the insect’s immune responses in the gut and haemocoel. This work focuses on the modulation of the humoral immune responses of the midgut of R. prolixus infected with T. Rangeli Macias strain, considering the influence of the parasite on the intestinal microbiota.

  • Trypanosoma Rangeli: A new perspective for studying the modulation of immune reactions of Rhodnius prolixus
    Parasites and Vectors, 2009
    Co-Authors: Eloi S. Garcia, Fernando A. Genta, Daniele P. Castro, Marcela B. Figueiredo, Patricia Azambuja
    Abstract:

    ABSTRACT: Insects are exposed to a wide range of microorganisms (bacteria, fungi, parasites and viruses) and have interconnected powerful immune reactions. Although insects lack an acquired immune system they have well-developed innate immune defences that allow a general and rapid response to infectious agents.Over the last few decades we have observed a dramatic increase in the knowledge of insect innate immunity, which relies on both humoral and cellular responses. However, innate reactions to natural insect pathogens and insect-transmitted pathogens, such as parasites, still remain poorly understood.In this review, we briefly introduce the general immune system of insects and highlight our current knowledge of these reactions focusing on the interactions of Trypanosoma Rangeli with Rhodnius prolixus, an important model for innate immunity investigation.

  • Trypanosoma Rangeli interactions within the vector Rhodnius prolixus - A mini review
    Memorias do Instituto Oswaldo Cruz, 2005
    Co-Authors: Patricia Azambuja, Eloi S. Garcia
    Abstract:

    This article is an integrative mini review of the research on the interactions between Trypanosoma Rangeli and the insect vector, Rhodnius prolixus. Special attention is given to the interactions of these parasites with the gut environment, gut walls, with hemolymph invasion, hemocytes, hemocyte microaggregations, prophenoloxidase-activating system, superoxide, and nitric acid generation and eicosanoid pathways. We described factors affecting vectorial capacity and suggested that T. Rangeli may modulate the hemocoelic invasion and the survival of the parasites by overcoming the cellular and humoral defense reactions of the insect vector at different physiological events. The mechanisms of these interactions and their significance for parasite transmission are discussed.

  • inhibition of hemocyte microaggregation reactions in rhodnius prolixus larvae orally infected with Trypanosoma Rangeli
    Experimental Parasitology, 2004
    Co-Authors: Eloi S. Garcia, Evandro M.m. Machado, Patricia Azambuja
    Abstract:

    Hemocoelic inoculation of epimastigotes of Trypanosoma Rangeli strain H14 into 5th-instar larvae of Rhodnius prolixus previously fed on blood containing the same parasites, showed reduced number of hemocyte microaggregates in the hemolymph, enhanced number of flagellates in the hemolymph as well as increased mortality of these insects. All these effects were counteracted by combined inoculation of R. prolixus with T. Rangeli and arachidonic acid. In vitro assays using hemolymph taken from insects previously fed on blood containing parasites showed that hemocyte microaggregation reactions were also attenuated when T. Rangeli is used as inducer of the reaction, and that simultaneous applying T. Rangeli with arachidonic counteracted the hemocyte microaggregation inhibition. We suggest that arachidonic acid pathway can be a mediator of hemocyte microaggregation reactions in the hemolymph of insects inoculated with T. Rangeli, and that oral infection with this protozoan inhibits the release of arachidonic acid.

  • Inhibition of hemocyte microaggregation reactions in Rhodnius prolixus larvae orally infected with Trypanosoma Rangeli
    Experimental Parasitology, 2004
    Co-Authors: Eloi S. Garcia, Evandro M.m. Machado, Patricia Azambuja
    Abstract:

    Hemocoelic inoculation of epimastigotes of Trypanosoma Rangeli strain H14 into 5th-instar larvae of Rhodnius prolixus previously fed on blood containing the same parasites, showed reduced number of hemocyte microaggregates in the hemolymph, enhanced number of flagellates in the hemolymph as well as increased mortality of these insects. All these effects were counteracted by combined inoculation of R. prolixus with T. Rangeli and arachidonic acid. In vitro assays using hemolymph taken from insects previously fed on blood containing parasites showed that hemocyte microaggregation reactions were also attenuated when T. Rangeli is used as inducer of the reaction, and that simultaneous applying T. Rangeli with arachidonic counteracted the hemocyte microaggregation inhibition. We suggest that arachidonic acid pathway can be a mediator of hemocyte microaggregation reactions in the hemolymph of insects inoculated with T. Rangeli, and that oral infection with this protozoan inhibits the release of arachidonic acid. © 2004 Elsevier Inc. All rights reserved.

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