Atividade inseticida de extratos de plantas do Cerrado em Rhodnius milesi Carcavallo, Rocha, Galvão & Jurberg (Hemiptera: Reduviidae), em Condições de Laboratório

A transmissão da doença de Chagas ocorre, principalmente, por meio de fezes de hemípteroshematófagos (Triatominae), os quais ingerem Trypanosoma cruzi ao se alimentarem do sangue de pessoas ou animais infectados. Para o controle dos triatomíneos, os piretróides são os principais inseticidas utilizados. Entretanto, algumas populações de insetos demonstraram resistência a determinados piretróides, indicando a necessidade do desenvolvimento de novos inseticidas eficazes no controle desses vetores. Assim, foi avaliada a atividade inseticida de 24 extratos vegetais em ninfas do quarto estádio de Rhodnius milesi Carcavallo, Rocha, Galvão & Jurberg, em condições de laboratório. Para o teste tópico, foram aplicados 50 μg de cada extrato nos tergitos abdominais de dez ninfas, em duplicata. Como controles, foram utilizados insetos tratados com etanol, acetona ou sem nenhum tipo de tratamento. Os triatomíneos foram observados durante 28 dias. Extratos hexânicos e etanólicos de Simarouba versicolor , Guarea kunthiana, Guarea guidonia e Talauma ovata causaram mortalidade entre 20% e 95% de R. milesi em comparação com os controles, onde não houve mortalidade dos insetos. Estes dados preliminares sugerem que o extrato etanólico da casca da raiz de S. versicolor e o extrato hexânico da raiz de G. guidonia, os quais foram responsáveis pela mortalidadede 95% e 75%, respectivamente, devem ser quimicamente investigados e monitorados por ensaios biológicos a fim de determinar seus componentes inseticidas, a serem utilisados como modelos moleculares ou como compostos biorracionais nos programas de controle de insetos.Chagas’ disease is chiefly transmitted by feces of haematophagous bugs (Triatominae)that ingested Trypanosoma cruzi from blood of infected people or animals. Pyrethroids have been the main insecticides used against these insects. However, some populations of insects have shown significant levels of resistance to several pyrethroids, indicating the need of new insecticides for the control of triatomines. Insecticidal activity of 24 Cerrado plant extracts belonging to five species of four families were assayed on fourth instar nymphs of Rhodnius milesi Carcavallo, Rocha, Galvão & Jurberg(Hemiptera: Reduviidae), under laboratory conditions. For the extract application on triatomines, 50 μg of the extract were topically applied in duplicate on dorsal tergites of ten insects. Insects topically treated with acetone, ethanol, as well as insects with no treatment were used as controls. Triatomineswere observed over a 28-day period. Hexanic and ethanolic extracts of Simarouba versicolor, Guareakunthiana, Guarea guidonia and Talauma ovata caused mortality between 20% and 95% of R. milesiin comparison with the controls, which showed no insect mortality. These preliminary data suggest that the ethanolic extract of the root bark of S. versicolor and the hexanic extract of the root of G. guidonia, responsible for a 95% and 75% insect mortality, respectively, should be chemically investigated and monitored through biological assays in order to determine their insecticidal components, that could beused as a molecular model or as biorational compounds for use in insect control programmes

Effect of cerrado plant extracts on Dipetalogaster maxima (Uhler) (Hemiptera, Reduviidae)

A transmissão da doença de Chagas ocorre, principalmente, por meio de fezes de hemípteros hematófagos (Triatominae), os quais ingerem o Trypanosoma cruzi ao se alimentarem do sangue de pessoas ou outros mamíferos infectados. Para o controle dos triatomíneos, os piretróides são os principais inseticidas utilizados. Entretanto, algumas populações de insetos demonstraram resistência a determinados piretróides, indicando a necessidade do desenvolvimento de novos inseticidas eficazes no controle desses vetores. Assim, foi avaliada a atividade inseticida de 83 extratos vegetais, pertencentes a 35 espécies diferentes, em ninfas do primeiro estádio de Dipetalogaster maxima (Uhler, 1894) (Hemiptera: Reduviidae), triatomíneo encontrado no México. Para o teste tópico, foram aplicados 50 ìg de cada extrato nos tergitos abdominais de dez ninfas, em duplicata. Como controles, foram utilizados insetos tratados com etanol, acetona ou sem nenhum tipo de tratamento. Os triatomíneos foram observados durante 28 dias. Nenhum extrato apresentou atividade inseticida significativa, entretanto, o extrato hexânico do fruto e o etanólico da casca do caule de Simarouba versicolor (Simaroubaceae) inibiram a taxa de ecdise em D. maxima (40% e 25%, respectivamente). Sugere-se que estes extratos sejam quimicamente investigados e monitorados por ensaios biológicos a fim de determinar os componentes, para que estes possam ser utilizados como modelos moleculares ou como compostos biorracionais nos programas de controle de insetos.Chagas disease, also known as American Trypanosomiasis, is chiefly transmitted by faeces of haematophagous bugs (Triatominae) that ingested Trypanosoma cruzi from blood of infected people or other mammals. Pyrethroids have been the main insecticides used against these insects. However, some populations of insects have shown significant levels of resistance to several pyrethroids, indicating the need of new insecticides for the control of triatomines. Thus, the insecticidal activity of 83 Cerrado plant extracts belonging to 35 species were assayed on first instar nymphs of Dipetalogaster maxima (Uhler, 1894) (Hemiptera, Reduviidae), species found in Mexico. For the extract application on triatomines, 50 μg of the extract were topically applied in duplicate on dorsal tergites of ten insects. Insects topically treated with acetone, ethanol, as well as insects with no treatment were used as controls. Triatomines were observed over a 28-day period. The extracts showed no insect mortality, however, fruit hexane and stem bark ethanolic extracts of Simarouba versicolor (Simaroubaceae) inhibited the rate of ecdysis in D. maxima (40% and 25%, respectively). These preliminary data suggest that this extracts should be chemically investigated and monitored through biological assays in order to determine the components, so that it may be used as a molecular model or as biorational compounds for use in insect control programmes

Registro e perfil ecotoxicológico de produtos para controle de Aedes aegypti

Introduction: Arboviruses transmitted by Aedes aegypti have big relevance for public health worldwide, with chemical vector control being an important mitigation strategy. Nevertheless, the intensive use of insecticides is associated with resistance and environmental toxicity. That is why it is essential to develop and regulate new products, effective and sustainable. Objective: To describe the requirements for regulation of insecticides and repellents in Brazil, in the light of international guidelines. To present, comparatively, the active ingredients approved in Brazil, United States (USA) and the European Union (EU). Finally, to conduct a survey of ecotoxicological studies from active ingredients used for vector control. Method: Narrative review of national and international regulatory instruments, scientific literature, consultation with regulatory agencies and assess to ECOTOX Knowledgebase. Results: Brazilian requirements are in line with international standards. All insecticides active ingredients available in the USA have a monograph approved in Brazil by the National Health Surveillance Agency; the EU was more restrictive. There are fewer topical repellents available in Brazil and in the EU, compared to the USA. Many of the insecticides approved for vector control pose a risk to non-target organisms. However, we did not identify studies for some of them in the researched database. Conclusions: The EU seems  to be the most restrictive agency when it comes to registering insecticides. Specific guides on development of innovative products for vector control are needed, as well as greater transparency in research instruments at the Brazilian agency website. This review also reiterates the necessity of more ecotoxicological analysis regarding insecticides, considering their potential environmental hazard. Introdução: Arboviroses transmitidas pelo Aedes aegypti têm grande relevância para a saúde pública, sendo o controle químico do vetor uma importante estratégia de mitigação. Entretanto, o uso intensivo de pesticidas está associado a seleção de insetos resistentes e impacto ambiental. Por isso, é essencial desenvolver e regulamentar novos produtos, eficazes e sustentáveis. Objetivo: Descrever os requisitos para regulação  de inseticidas e repelentes no Brasil, à luz de orientações internacionais. Comparar os ativos regulamentados no país com os disponíveis nos Estados Unidos (EUA) e União Europeia (UE). Por fim, realizar um levantamento de estudos ecotoxicológicos dos ativos empregados no controle vetorial. Método: Revisão narrativa de instrumentos regulatórios nacionais e internacionais, literatura científica, consulta a agências regulatórias e ao ECOTOX Knowledgebase. Resultados: As normas brasileiras trazem exigências consoantes com as internacionais. Todos os ativos disponíveis nos EUA têm monografia aprovada pela Anvisa; já a UE mostrou-se mais restritiva. Há menos repelentes tópicos disponíveis no Brasil e na UE, comparando-se com EUA. Muitos dos inseticidas aprovados para controle vetorial representam risco para organismos não alvo. Ainda assim, não identificamos quaisquer estudos para alguns dos produtos no banco de dados pesquisado. Conclusões:  A UE mostrou-se a agência mais restritiva com relação ao registro de inseticidas. Existe a necessidade de guias com orientações específicas sobre o desenvolvimento de produtos inovadores para o controle do mosquito, bem como de ferramentas de busca com maior transparência na página da agência brasileira. Finalmente, esta revisão reitera a importância de análises ecotoxicológicas mais abrangentes para os produtos em questão, considerando seu potencial dano ambiental

Antileishmanial and trypanocidal activity of brazilian Cerrado plants

The side effects and the emerging resistance to the available drugs against leishmaniasis and trypanosomiasis led to the urgent need for new therapeutic agents against these diseases. Thirty one extracts of thirteen medicinal plants from the Brazilian Cerrado were therefore evaluated in vitro for their antiprotozoal activity against promastigotes of Leishmania donovani, and amastigotes of Trypanosoma cruzi. Among the selected plants, Casearia sylvestris var. lingua was the most active against both L. donovani and T. cruzi. Fifteen extracts were active against promastigotes of L. donovani with concentrations inhibiting 50% of parasite growth (IC50) between 0.1-10 µg/ml, particularly those of Annona crassiflora (Annonaceae), Himatanthus obovatus (Apocynaceae), Guarea kunthiana (Meliaceae), Cupania vernalis (Sapindaceae), and Serjania lethalis (Sapindaceae). With regard to amastigotes of T. cruzi, extracts of A. crassiflora, Duguetia furfuracea (Annonaceae), and C. sylvestris var. lingua were active with IC50 values between 0.3-10 µg/ml. Bioassay fractionations of the more active extracts are under progress to identify the active antiparasite compounds

Molecular and cellular biomarkers of COVID-19 prognosis : protocol for the prospective cohort TARGET study

Background: Since the beginning of the COVID-19 pandemic, the world’s attention has been focused on better understanding the relation between the human host and the SARS-CoV-2 virus, as its action has led to hundreds of thousands of deaths. Objective: In this context, we decided to study certain consequences of the abundant cytokine release over the innate and adaptive immune systems, inflammation, and hemostasis, comparing mild and severe forms of COVID-19. Methods: To accomplish these aims, we will analyze demographic characteristics, biochemical tests, immune biomarkers, leukocyte phenotyping, immunoglobulin profile, hormonal release (cortisol and prolactin), gene expression, thromboelastometry, neutralizing antibodies, metabolic profile, and neutrophil function (reactive oxygen species production, neutrophil extracellular trap production, phagocytosis, migration, gene expression, and proteomics). A total of 200 reverse transcription polymerase chain reaction–confirmed patients will be enrolled and divided into two groups: mild/moderate or severe/critical forms of COVID-19. Blood samples will be collected at different times: at inclusion and after 9 and 18 days, with an additional 3-day sample for severe patients. We believe that this information will provide more knowledge for future studies that will provide more robust and useful clinical information that may allow for better decisions at the front lines of health care. Results: The recruitment began in June 2020 and is still in progress. It is expected to continue until February 2021. Data analysis is scheduled to start after all data have been collected. The coagulation study branch is complete and is already in the analysis phase

Panoramic snapshot of serum soluble mediator interplay in pregnant women with convalescent COVID-19: an exploratory study

IntroductionSARS-CoV-2 infection during pregnancy can induce changes in the maternal immune response, with effects on pregnancy outcome and offspring. This is a cross-sectional observational study designed to characterize the immunological status of pregnant women with convalescent COVID-19 at distinct pregnancy trimesters. The study focused on providing a clear snapshot of the interplay among serum soluble mediators.MethodsA sample of 141 pregnant women from all prenatal periods (1st, 2nd and 3rd trimesters) comprised patients with convalescent SARS-CoV-2 infection at 3-20 weeks after symptoms onset (COVID, n=89) and a control group of pre-pandemic non-infected pregnant women (HC, n=52). Chemokine, pro-inflammatory/regulatory cytokine and growth factor levels were quantified by a high-throughput microbeads array.ResultsIn the HC group, most serum soluble mediators progressively decreased towards the 2nd and 3rd trimesters of pregnancy, while higher chemokine, cytokine and growth factor levels were observed in the COVID patient group. Serum soluble mediator signatures and heatmap analysis pointed out that the major increase observed in the COVID group related to pro-inflammatory cytokines (IL-6, TNF-α, IL-12, IFN-γ and IL-17). A larger set of biomarkers displayed an increased COVID/HC ratio towards the 2nd (3x increase) and the 3rd (3x to 15x increase) trimesters. Integrative network analysis demonstrated that HC pregnancy evolves with decreasing connectivity between pairs of serum soluble mediators towards the 3rd trimester. Although the COVID group exhibited a similar profile, the number of connections was remarkably lower throughout the pregnancy. Meanwhile, IL-1Ra, IL-10 and GM-CSF presented a preserved number of correlations (≥5 strong correlations in HC and COVID), IL-17, FGF-basic and VEGF lost connectivity throughout the pregnancy. IL-6 and CXCL8 were included in a set of acquired attributes, named COVID-selective (≥5 strong correlations in COVID and <5 in HC) observed at the 3rd pregnancy trimester.Discussion and conclusionFrom an overall perspective, a pronounced increase in serum levels of soluble mediators with decreased network interplay between them demonstrated an imbalanced immune response in convalescent COVID-19 infection during pregnancy that may contribute to the management of, or indeed recovery from, late complications in the post-symptomatic phase of the SARS-CoV-2 infection in pregnant women

Recherche de composés antifongiques issus de bois durables amazoniens

Aujourd hui, il est indispensable de découvrir de nouveaux agents thérapeutiques pour faire face à l expansion des infections fongiques humaines. D un autre côté, certains arbres amazoniens ont acquis des moyens pour se protéger contre la dégradation fongique. Ces composés d origine végétale pourraient donc être des candidats potentiels au développement de composés antifongiques. Il est ainsi exposé dans ce travail la sélection bio-inspirée et la récolte d espèces d arbres amazoniens résistants à la dégradation fongique ; à partir desquelles il est proposé d isoler, d identifier et de valoriser les métabolites responsables de la durabilité naturelle et d étudier leurs propriétés sur des champignons pathogènes humains. Cette étude à conduit à l isolement de molécules inédites apportant un complément d information chimiotaxonomique pour les espèces étudiées. De plus, il a pu être mis en avant deux molécules pouvant devenir des composés pertinents pour le développement de traitements antimycotiques.It is now essential to discover new therapeutic agents against the increase human fungal infections. On the order hand, some Amazonian trees have succeeded to develop a chemical defense arsenal to protect themselves against fungal degradation. These compounds of plant origin could become potential candidates for the development of antifungal compounds for the treatment of human fungal diseases. Therefore, this manuscript describes the bio-inspired selection and collection of Amazonian tree species capable of specializing a highly fungi-resistant wood; from which it is proposed to isolate; identify and valorize the secondary metabolites responsible for the natural durability, and study their properties on human pathogenic fungi. Ultimately, this study led to isolation of new compounds and providing additional important chemotaxonomic information for the species studied. In addition, it as been established that two compounds could be relevant for the development of antimitotic therapies.CAYENNE-BU (973022101) / SudocSudocFranceF

Activités antiparasitaires et antifongiques des plantes du Cerrado (Spiranthera odoratissima et Diospyros hispida)

PARIS-Museum Hist.Naturelle (751052304) / SudocSudocFranceF