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

  • Azadirachtin interferes with basal immunity and microbial homeostasis in the Rhodnius Prolixus midgut.
    Developmental and comparative immunology, 2020
    Co-Authors: Cecilia Stahl Vieira, Daniele P. Castro, Marcela B. Figueiredo, Caroline S. Moraes, Suelen Bastos Pereira, Paul Dyson, Cicero B. Mello, Patrícia Azambuja
    Abstract:

    Rhodnius Prolixus is an insect vector of two flagellate parasites, Trypanosoma rangeli and Trypanosoma cruzi, the latter being the causative agent of Chagas disease in Latin America. The R. Prolixus neuroendocrine system regulates the synthesis of the steroid hormone ecdysone, which is essential for not only development and molting but also insect immunity. Knowledge for how this modulates R. Prolixus midgut immune responses is essential for understanding interactions between the vector, its parasites and symbiotic microbes. In the present work, we evaluated the effects of ecdysone inhibition on R. Prolixus humoral immunity and homeostasis with its microbiota, using the triterpenoid natural product, azadirachtin. Our results demonstrated that azadirachtin promoted a fast and lasting inhibitory effect on expression of both RpRelish, a nuclear factor kappa B transcription factor (NF-kB) component of the IMD pathway, and several antimicrobial peptide (AMP) genes. On the other hand, RpDorsal, encoding the equivalent NF-kB transcription factor in the Toll pathway, and the defC AMP gene were upregulated later in azadirachtin treated insects. The treatment also impacted on proliferation of Serratia marcescens, an abundant commensal bacterium. The simultaneous administration of ecdysone and azadirachtin in R. Prolixus blood meals counteracted the azadirachtin effects on insect molting and also on expression of RpRelish and AMPs genes. These results support the direct involvement of ecdysone in regulation of the IMD pathway in the Rhodnius Prolixus gut.

  • Rhodnius Prolixus interaction with trypanosoma rangeli modulation of the immune system and microbiota population
    Parasites & Vectors, 2015
    Co-Authors: Cecilia Stahl Vieira, Daniele P. Castro, Marcela B. Figueiredo, Debora P Mattos, Marcia Gumiel, Peter J Waniek, Fabio Faria Da Mota, Eloi S. Garcia, Jayme M Santangelo, Patrícia 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.

  • Phase Contrast X-Ray Synchrotron Microtomography for Virtual Dissection of the Head of Rhodnius Prolixus
    Journal of Physics: Conference Series, 2014
    Co-Authors: G. Sena, Eloi S. Garcia, Patrícia Azambuja, A.p. Almeida, Delson Braz, L.p. Nogueira, M.v. Colaço, J. Soares, Simone C. Cardoso, Marcelo S. Gonzalez
    Abstract:

    Phase Contrast X-Ray Synchroton Microtomography is a non-destructive technique that allows the microanatomical investigations of Rhodnius Prolixus, one of the most important insect vectors of Trypanosoma cruzi. In this work complete series of virtual thin sections through the heads of selected Rhodnius Prolixus were obtained. The sections of the head were important to compare the difference in use the spatial resolution of 2 μm or 4.5 μm and to see anatomical details that couldn't be seen with other technique. Three different groups of Rhodnius Prolixus were used. One group was fed with defibrinated rabbit blood and after 10 days was sacrificed, other group was sacrificed 4 days after feeding and the last group remained unfed. The results show some differences for each kind of groups and for the different resolutions.

  • Application of the SR-PhC-μCT technique with phase retrieval for the characterization of internal and external structures of Rhodnius Prolixus
    Journal of Instrumentation, 2013
    Co-Authors: André Pereira De Almeida, Eloi S. Garcia, Patrícia Azambuja, Delson Braz, L.p. Nogueira, M.v. Colaço, J. Soares, Simone C. Cardoso, Marcelo S. Gonzalez, Sara Mohammadi
    Abstract:

    The present work is the second one of a two- part publication on the use of Synchrotron Radiation Phase Contrast microtomography (SR-PhC-μCT) for the study of Rhodnius Prolixus morphology. In previous paper the visualization of various detailed features were highlighted thanks to the edge enhancement effects typical of the phase contrast technique, but the contrast between foreground and background remained poor. In this study the same data set have been re-visited with application of a single distance phase retrieval algorithm. The resulting slices showed very high quality images that enable a better visualization of important muscles and neurohemal organs of the central nervous system within the head of Rhodnius Prolixus.

  • Trypanosoma rangeli interactions within the vector Rhodnius Prolixus - A mini review
    Memorias do Instituto Oswaldo Cruz, 2005
    Co-Authors: Patrícia 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.

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, Daniele P. Castro, Marcela B. Figueiredo, Debora P Mattos, Marcia Gumiel, Peter J Waniek, Fabio Faria Da Mota, Eloi S. Garcia, Jayme M Santangelo, Patrícia 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.

  • Phase Contrast X-Ray Synchrotron Microtomography for Virtual Dissection of the Head of Rhodnius Prolixus
    Journal of Physics: Conference Series, 2014
    Co-Authors: G. Sena, Eloi S. Garcia, Patrícia Azambuja, A.p. Almeida, Delson Braz, L.p. Nogueira, M.v. Colaço, J. Soares, Simone C. Cardoso, Marcelo S. Gonzalez
    Abstract:

    Phase Contrast X-Ray Synchroton Microtomography is a non-destructive technique that allows the microanatomical investigations of Rhodnius Prolixus, one of the most important insect vectors of Trypanosoma cruzi. In this work complete series of virtual thin sections through the heads of selected Rhodnius Prolixus were obtained. The sections of the head were important to compare the difference in use the spatial resolution of 2 μm or 4.5 μm and to see anatomical details that couldn't be seen with other technique. Three different groups of Rhodnius Prolixus were used. One group was fed with defibrinated rabbit blood and after 10 days was sacrificed, other group was sacrificed 4 days after feeding and the last group remained unfed. The results show some differences for each kind of groups and for the different resolutions.

  • Application of the SR-PhC-μCT technique with phase retrieval for the characterization of internal and external structures of Rhodnius Prolixus
    Journal of Instrumentation, 2013
    Co-Authors: André Pereira De Almeida, Eloi S. Garcia, Patrícia Azambuja, Delson Braz, L.p. Nogueira, M.v. Colaço, J. Soares, Simone C. Cardoso, Marcelo S. Gonzalez, Sara Mohammadi
    Abstract:

    The present work is the second one of a two- part publication on the use of Synchrotron Radiation Phase Contrast microtomography (SR-PhC-μCT) for the study of Rhodnius Prolixus morphology. In previous paper the visualization of various detailed features were highlighted thanks to the edge enhancement effects typical of the phase contrast technique, but the contrast between foreground and background remained poor. In this study the same data set have been re-visited with application of a single distance phase retrieval algorithm. The resulting slices showed very high quality images that enable a better visualization of important muscles and neurohemal organs of the central nervous system within the head of Rhodnius Prolixus.

  • Degradation of the neolignan, burchellin in the hemolymph of the bloodsucking insect Rhodnius Prolixus.
    Fitoterapia, 2007
    Co-Authors: Marise M. O. Cabral, Eloi S. Garcia, Otto R. Gottlieb, Alphonse Kelecom
    Abstract:

    The neolignan, burchellin, a natural compound that reduces urine excretion in larvae of the bloodsucking bug, Rhodnius Prolixus, a vector of Chagas' disease, is rapidly degraded in the hemolymph of the insect. The main product that accumulates in this tissue has been shown to be piperonyl alcohol. Other catabolites have been identified by GC-MS analysis.

  • Trypanosoma rangeli interactions within the vector Rhodnius Prolixus - A mini review
    Memorias do Instituto Oswaldo Cruz, 2005
    Co-Authors: Patrícia 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.

Eduardo Zerba - One of the best experts on this subject based on the ideXlab platform.

  • Rhodnius Prolixus intoxicated
    Journal of insect physiology, 2016
    Co-Authors: Raúl Adolfo Alzogaray, Eduardo Zerba
    Abstract:

    Abstract Rhodnius Prolixus (Hemiptera: Reduviidae) is a hematophagous insect native from South America. By the end of the 20th century, it was one of the main vectors of Chagas disease in Venezuela, Colombia, several Central American countries and southern Mexico. The aim of the present article is to review the literature regarding R. Prolixus toxicology. British entomologist Vincent B. Wigglesworth carried out the first studies on this subject over seventy years ago. A wide bibliographical search allowed to locate one hundred and thirty scientific articles describing the effects of different insecticides on R. Prolixus . About one-third of these articles report the acute toxicity and/or sublethal effects produced by the main synthetic neurotoxic families of insecticides (organochlorines, organophosphates, carbamates and pyrethroids). Only a couple of these studies have regarded the toxicokinetics or toxicodynamics of these insecticides. Insect growth or development disruptors, such as juvenoids, chitin synthesis inhibitors, precocenes, azadirachtin and lignoids, have been thoroughly studied in R. Prolixus . Important aspects on the mode of action of ureases were also described in this species. By the end of the 1960’s, resistance to insecticides was detected in R. Prolixus from Venezuela. Some years later, the existence of pyrethroid-resistant individuals was also reported. Control programmes for R. Prolixus in countries where Chagas is endemic have only used synthetic neurotoxic insecticides. In 2011, Central America and southern Mexico were declared free of this insect. The recent sequencing of the R. Prolixus genome will provide valuable information to understand the molecular basis of insecticide resistance in this species.

  • insecticide resistance in brazilian triatoma infestans and venezuelan Rhodnius Prolixus
    Medical and Veterinary Entomology, 2000
    Co-Authors: Claudia V Vassena, Maria Ines Picollo, Eduardo Zerba
    Abstract:

    Summary Resistance levels to insecticides used in control of Chagas Disease vectors were assessed in two species of bugs (Hemiptera: Reduviidae): Triatoma infestans (Klug) from Brazil and Rhodnius Prolixus Stal from Venezuela. The resistance ratios, compared to susceptible laboratory strains, were determined by topical application bioassays. The T. infestans PA strain exhibited resistance ratios of 7× to deltamethrin, 3.6× to β-cyfluthrin and 3.3× to cypermethrin, but was susceptible to β-cypermethrin and lambda-cyhalothrin. Rhodnius Prolixus CA strain showed resistance to all the pyrethroids evaluated, the resistance ratios ranging between 4.5× to lambda-cyhalothrin and 12.4× to cypermethrin. Deltamethrin resistance in both strains was decreased by piperonyl butoxide, suggesting oxidative metabolism as cause of resistance.

Cecilia Stahl Vieira - One of the best experts on this subject based on the ideXlab platform.

  • Azadirachtin interferes with basal immunity and microbial homeostasis in the Rhodnius Prolixus midgut.
    Developmental and comparative immunology, 2020
    Co-Authors: Cecilia Stahl Vieira, Daniele P. Castro, Marcela B. Figueiredo, Caroline S. Moraes, Suelen Bastos Pereira, Paul Dyson, Cicero B. Mello, Patrícia Azambuja
    Abstract:

    Rhodnius Prolixus is an insect vector of two flagellate parasites, Trypanosoma rangeli and Trypanosoma cruzi, the latter being the causative agent of Chagas disease in Latin America. The R. Prolixus neuroendocrine system regulates the synthesis of the steroid hormone ecdysone, which is essential for not only development and molting but also insect immunity. Knowledge for how this modulates R. Prolixus midgut immune responses is essential for understanding interactions between the vector, its parasites and symbiotic microbes. In the present work, we evaluated the effects of ecdysone inhibition on R. Prolixus humoral immunity and homeostasis with its microbiota, using the triterpenoid natural product, azadirachtin. Our results demonstrated that azadirachtin promoted a fast and lasting inhibitory effect on expression of both RpRelish, a nuclear factor kappa B transcription factor (NF-kB) component of the IMD pathway, and several antimicrobial peptide (AMP) genes. On the other hand, RpDorsal, encoding the equivalent NF-kB transcription factor in the Toll pathway, and the defC AMP gene were upregulated later in azadirachtin treated insects. The treatment also impacted on proliferation of Serratia marcescens, an abundant commensal bacterium. The simultaneous administration of ecdysone and azadirachtin in R. Prolixus blood meals counteracted the azadirachtin effects on insect molting and also on expression of RpRelish and AMPs genes. These results support the direct involvement of ecdysone in regulation of the IMD pathway in the Rhodnius Prolixus gut.

  • Rhodnius Prolixus interaction with trypanosoma rangeli modulation of the immune system and microbiota population
    Parasites & Vectors, 2015
    Co-Authors: Cecilia Stahl Vieira, Daniele P. Castro, Marcela B. Figueiredo, Debora P Mattos, Marcia Gumiel, Peter J Waniek, Fabio Faria Da Mota, Eloi S. Garcia, Jayme M Santangelo, Patrícia 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.

Kenneth G. Davey - One of the best experts on this subject based on the ideXlab platform.

  • The interaction of feeding and mating in the hormonal control of egg production in Rhodnius Prolixus
    Journal of insect physiology, 2006
    Co-Authors: Kenneth G. Davey
    Abstract:

    The evidence relating feeding and mating to hormonal control of egg production in Rhodnius Prolixus is reviewed from two perspectives. It identifies crucial areas in which information is lacking, and it attempts to relate the findings, most of which have been obtained on laboratory colonies isolated for many years, to the sylvan life of the insect as an opportunistic micropredator.

  • The role of juvenile hormone in vitellogenin production in Rhodnius Prolixus
    Journal of Insect Physiology, 1993
    Co-Authors: Zhiwei Wang, Kenneth G. Davey
    Abstract:

    Abstract Following feeding in adult females of Rhodnius Prolixus, vitellogenin titres in the haemolymph, as determined by rocket immuno-electrophoresis, reach a higher level in mated females than in virgins. Allatectomy early in adult life decreases, but does not entirely abolish, vitellogenin levels in the haemolymph of fed females, confirming that juvenile hormone is not an absolute requirement for vitellogenin synthesis in this species. Topical application of 100 ng of juvenile hormone to allatectomized females restores the titre of vitellogenin in the haemolymph to normal levels, but fails to stimulate vitellin accumulation in the ovary. Treatment with 100 μg restores both vitellogenin and vitellin levels to normal. This is interpreted as being due to a differential sensitivity to juvenile hormone of the mechanisms governing synthesis and uptake.

  • A sensorory input inhibiting heart rate in an insect, Rhodnius Prolixus
    Cellular and Molecular Life Sciences, 1992
    Co-Authors: R. G. Chiang, J. A. Chiang, Kenneth G. Davey
    Abstract:

    The dorsal vessel of the blood feeding insect,Rhodnius Prolixus, was found to increase or decrease its rate of contraction in response to a number of different stimuli. Handling increased contraction rates whereas tactile stimulation of the ventral abdominal cuticle inhibited contraction. Injection of very low concentrations of serotonin or of high concentrations of octopamine enhanced the inhibitory effect, apparently by acting via the nervous system. Higher concentrations of serotonin increased heart rate by acting directly on the myocardium. The inhibitory response is suggested to be one facet of a generalised thigmotactic response.