991 resultados para neotropical Leishmania
Resumo:
Constrictotermes cyphergaster (Silvester, 1901) builds arboreal nests in Brazilian Cerrado stricto sensu, which are frequently cohabited by inquilines termites and by termitophiles. In a study made at the Parque Estadual da Serra de Caldas Novas, Goiás, Brazil, there were four nests with multiple reproductives, and secondary reproductives were found in 26 nests. Nymphs of Inquilinitermes were more abundant (9,47%) than nymphs of C. cyphergaster (0,78%).
Resumo:
The Neotropical genus Xanthandrus Verral, 1901 is revised. Six species are redescribed: X. bucephalus (Wiedemann, 1830), X. cubanus Fluke, 1936, X. mellinoides (Macquart, 1846), X. mexicanus Curran, 1930, X. nitidulus Fluke, 1937, and X. plaumanni Fluke, 1937. Three species are included based on original descriptions: X. flavomaculatus Shannon, 1927, X. palliatus (Fluke, 1945), and X. simplex (Loew, 1861). New synonyms proposed: Argentinomyia longicornis (Walker, 1837) = Xanthandrus biguttatus Hull, 1945 syn. nov., and Xanthandrus bucephalus (Wiedemann, 1830) = Melanostoma quadrinotata Bigot, 1884 syn. nov. Description of terminalia, a key for Neotropical species, and illustrations are also presented.
Resumo:
Unanthribus gen. nov. is proposed to include Unanthribus maximus sp. nov. (type species) described from Brazil (Pará), and U. grandis (Jordan, 1911) comb. nov., which is redescribed. The species are illustrated and keyed.
Resumo:
We investigated the functional role of the Leishmania histone H1 and demonstrate for the first time that addition of histone H1 has a strong effect on microccocal digestion, chromatin condensation of parasite nuclei and that its overexpression can modulate parasite infectivity in vivo.
Resumo:
As leishmanioses são um complexo de doenças infecto-parasitárias endêmicas em 88 países que constituem um grave problema de saúde pública. Diversas espécies do gênero Leishmania são os agentes causadores da doença, dentre elas a espécie L. (V.) braziliensis associada a diferentes quadros clínicos da Leishmaniose Tegumentar Americana. No presente trabalho foram obtidos nove isolados de Leishmania sp. oriundos de LTA, sendo sete isolados (87%) oriundos de pacientes residentes no município de Pilões, um (13%) da cidade de João Pessoa, ambas regiões, do estado da Paraíba. Todos os nove isolados foram identificados como sendo da espécie L. (V.) braziliensis através de PCR específica. As análises de caracterização molecular pela técnica de RAPD-PCR mostraram que esses isolados compartilharam 62,63% revelando diferenças genotípicas entre elas. Contudo, os isolados AF e JSL, ambos provenientes de lesões disseminadas, tiveram o maior percentual de bandas compartilhadas dentre os isolados. Outra técnica molecular utilizada foi o SSR-PCR com o iniciador K7 que também foi capaz de demontrar polimorfismo entre os isolados. Nas análises de PCR-RLFP das regiões ITS1, foram encontradas perfis diferentes entre os isolados, onde MRSS, JMTS, AF, JCTS, JRL apresentaram o mesmo perfil de bandas e os isolados JSL, JCNS, MFTS e JAS tiveram, cada um, perfis de bandas distintos. Na análise de PCR-RLFP da região do gene hsp70, JSL, AF, JCTS, JRL, MFTS apresentaram o mesmo perfil de bandas e os isolados, MRSS, JMTS, JCNS e JAS perfis de bandas distintos. Adicionalmente foram também observadas diferenças fenotípicas entre estes isolados, visto que em dado momento de cultivo, todos apresentaram comportamento diferenciado, além de demonstrarem diferenças quanto à sensibilidade às drogas utilizadas na terapêutica das leishmanioses. Portanto estes estudos revelam que os isolados de L. (V.) braziliensis obtidos no estado da Paraíba demonstraram um significativo polimorfismo genético, revelando um alto nível de variação intraespecífica.
Resumo:
Mallodon vermiculatus sp. nov. (from Panama) and Nothopleurus santacruzensis sp. nov. (from Bolivia) are described and illustrated. Mallodon dasystomus dasystomus (Say, 1824) = M. mandibularis Lackerbeck, 1998 syn. nov.
Resumo:
Novos táxons descritos em Apomecynini: Eyiaba gen. nov., com duas espécies novas, E. picta sp. nov. (Brasil: São Paulo) e E. itapetinga sp. nov. (Brasil: Bahia); Adetus jacareacanga sp. nov. (Brasil: Pará) e Parmenonta dominicana sp. nov. (República Dominicana). Chave para identificação das espécies de Eyiaba é fornecida.
Resumo:
Le protozoaire unicellulaire Leishmania est l'agent responsable de la leishmaniose, une maladie parasitaire humaine qui se manifeste par des lésions de la peau, se résolvant le plus souvent spontanément, jusqu'à des lésions viscérales fatales. Le parasite est transmis de l'insecte à l'hôte mammifère lors d'un repas sanguin de la mouche des sables et y réside respectivement sous formes extra- et intracellulaires. On estime que cette maladie touche environ 12 millions de personnes dans 98 pays. Etant donné que les médicaments disponibles à ce jour sont faiblement efficaces et/ou hautement toxiques, il est indispensable de consolider les connaissances sur le fonctionnement et la survie du parasite pour pouvoir développer de nouvelles stratégies de traitements et de préventions. Tous les organismes vivants, dont Leishmania, contiennent du polyphopshate (polyP). Cette molécule chargée négativement est constituée de trois jusqu'à plusieurs centaines de résidus de phosphates reliées par des liaisons à haute énergie. Le polyP sert donc de source d'énergie et de réservoir de phosphate; dans certaines espèces, il joue aussi un rôle dans l'adaptation au stress et la virulence de pathogènes. Ceci nous a amené à étudier le rôle du polyP dans le parasite Leishmania. L'enzyme responsable de la synthèse de polyP a été identifié récemment dans la levure : il s'agit de la chaperone de transport vacuolaire 4 (Vtc4). Nous avons identifié un homologue de Vtc4 chez les Trypanosomatidae, et avons donc décidé d'examiner sa fonction dans le métabolisme du polyP chez Leishmania. En éliminant l'expression de Vtc4 chez L. major et L. guyanensis, nous avons pu démontrer qu'il est indispensable pour la production de polyP chez Leishmania. De plus, nous avons constaté que ces parasites possèdent des chaînes de polyP allant de trois jusqu'à environ 300 résidus de phosphate. Le taux de polyP dans la cellule est précisément régulé et varie entre un très haut niveau durant la phase proliférative des promastigotes à un niveau bas en phase stationnaire tardive, alors que l'expression de Vtc4p reste stable. Dans les amastigotes intracellulaires, seulement des petites quantités de polyP et de Vtc4p sont détectées. En outre, l'absence de Vc4p et de polyP n'a pas d'effet significatif sur les infections in vivo de souris, ce qui indique que le polyP n'est pas nécessaire au développement de la leishmaniose. Ceci suggère que Vtc4p n 'est pas une bonne cible pour le développement de nouveaux traitements contre Leishmania. "Néanmoins, la présence du polyP favorise fortement la survie du parasite suite à un choc de température (37°C) et aide ainsi à sa persistance intracellulaire pendant les premiers jours d'infection de macrophages. En résumé, nos résultats indiquent que si le polyP a peu d'importance pendant l'infection et le développement de la leishmaniose chez la souris, il est par contre crucial pour l'adaptation à des situations de stress comme l'augmentation de la température. Le fait que le polyP a été conservé dans tous les organismes durant l'évolution suggère toutefois que cette molécule joue un rôle fondamental. Etant donné que l'absence de polyP n'a pas d'effet sur la survie des amastigotes, il pourrait être plus important dans la forme promastigote infectant la mouche des sables. - The unicellular protozoan parasite Leishmania is the causative agent of the human disease leishmaniasis, which can range from self-healing skin lesions to fatal visceral lesions. The parasite is transmitted from the insect vector to the mammalian host when the sand fly takes its blood meal and exists in an extra- and an intracellular form, respectively. The disease is estimated to affect 12 million people in 98 countries and currently available drug treatments are of relatively low potency and/or high toxicity. Thus, investigating parasite survival mechanisms and parasite adaptation to the two host environments contributes to the general understanding of Leishmania propagation and might therefore help to develop future treatments or preventions. All living cells, including Leishmania, contain a negatively charged polymer of a few up to several hundred phosphate residues. These so-called polyphosphates (polyPs) serve as an energy source and phosphate reservoir. In some organisms, polyP is also involved in adaptation to stresses and virulence of pathogens. Therefore we were interested in investigating the importance of polyP in Leishmania parasites. Recently, an eukaryotic enzyme responsible for polyP synthesis has been identified as the vacuolar transporter chaperone 4 (Vtc4) in yeast. We, and others, found a Vtc4 homologue in trypanosomatids and decided to examine its potential function in polyP metabolism. By generating VTC4 knock-out cell lines in L. major and Vtc4 knock-down cell lines in L. guyanensis, we were able to demonstrate that Vtc4p is responsible for the total amount of cellular polyP. We also observed that Leishmania polyP chain length ranges from a few up to around 300 residues and that its level is tightly regulated. PolyP abundance is highest during the logarithmic proliferating phase of promastigotes and decreases in the stationary phase, while Vtc4 protein expression remains stable during both phases. In the intracellular amastigote form, only low amounts of polyP and Vtc4p were detectable. Furthermore, absence of Vtc4p and polyP did not have a significant effect on in vivo mouse infections, indicating that polyP is not necessary for Leishmania disease progression. This suggests that Vtc4p would be a poor drug target against Leishmania infection. However, presence of the polymer strongly supported parasite survival during heat shock (37°C) and thereby promoted intracellular persistence during the first days of macrophage infections. Taken together, we found that polyP has little importance in Leishmania {in vivo) infection but that it plays a crucial role during adaptation to stress, such as heat shock. Given that polyP has been preciously conserved in all organisms during evolution it seems to play a fundamental role. Since absence of polyP does not affect amastigote survival, it might be significant for promastigote existence in the sand fly vector.
Resumo:
Cytokines are increasingly recognized as important components of the cellular immune responses to intracellular pathogens. In this study, we analyzed the production of TGF-beta, IL-10 and IFN-gamma by PBMC of unexposed naïve subjects and LCL patients after stimulation with live Leishmania guyanensis (L.g.). We demonstrated that IFN-gamma is produced in controls and LCL patients, IL-10 only in LCL patients and TGF-beta only in naïve subjects. Furthermore, in naive subjects, neutralization of TGF-beta induced IL-10 production. IL-10 produced in naïve subjects when TGF-beta is neutralized or in LCL patients did not modify the IFN-gamma production but inhibit reactive nitrogen species production. Analysis of the phenotype of IL-10 producing cells in naive subjects when TGF-beta is neutralized clearly showed that they are memory CD45RA- CD8+ T cells. In LCL patients, IL-10 producing cells are both CD45RA- CD4 and CD8+ T cells. The role of these IL-10 producing CD8+ T cells in the development of the diseases should be carefully evaluated.
Resumo:
In order to investigate the affinities of the hitherto considered Neotropical Cleomenini genera, a detailed morphological comparative study was carried out based on representatives of their type species and other congeneric species. The results, when compared with representatives of Cleomenes Thomson and other non Neotropical Cleomenini genera together with representatives of Rhopalophorini Blanchard and Rhinotragini Thomson, show that: 1) Listroptera Audinet-Serville, 1834, Dihammaphora Chevrolat, 1859, Haenkea Tippmann, 1953, Aguassay Napp & Mermudes, 2001 and Timabiara Napp & Mermudes, 2001 form a very homogeneous group, not related to other Cleomenini, but sharing several synapomorphies with the Rhopalophorini; therefore they are herein transferred to this tribe; 2) the affinities of Dihammaphoroides Zajciw, 1967, were not clearly defined, needing further investigations; nevertheless, the genus is tentatively included in Rhopalophorini due to its morphological similarity with Dihammaphora and allied genera; 3) Pandrosos Bates, 1867 is brought back to Rhinotragini, in which it was originally placed. Therefore, the tribe Cleomenini Lacordaire is no longer represented in the New World.
Resumo:
O gênero Kroeberia e a espécie K. fuliginosa Lindner, 1930, são redescritos. Uma espécie nova, K. minor, é descrita do Brasil (Pará e Amazonas). As duas espécies são ilustradas e uma chave de identificação é fornecida.
Resumo:
The following new taxa of South American Cercopidae are described: Ferorhinella gen. nov., with type species Sphenorhina brevis Walker, 1851; Deois (Deois) knighti sp. nov. (Brazil), Deois (Deois) sexpunctata sp. nov. (Brazil), Deois (Pandysia) constricta sp. nov. (Brazil), Mahanarva (Ipiranga) bahiaensis sp. nov. (Brazil), Maxantonia bifurcata sp. nov. (Brazil), Neosphenorhina curvipenis sp. nov. (Brazil), Sphenorhina brevispina sp. nov. (Ecuador), Sphenorhina nigricephala sp. nov. (Ecuador), Sphenorhina minuta sp. nov. (Brazil), Tropidorhinella onorei sp. nov. (Colombia), Zuata luteofascia sp. nov. (Colombia). Ferorhinella brevis (Walker, 1851) comb. nov. In addition, descriptions are given for a new colour form of Mahanarva (M.) phantastica (Breddin, 1904) and a newly found variation in the male genitalia of Deoisella fasciata Costa & Sakakibara, 2002.
Resumo:
The following new species of South American Cercopidae, are described: Ischnorhina quadrimelasma sp. nov. (Bolivia), Laccogrypota quadrilineata sp. nov. (Bolivia), (Neolaccogrypota youngi sp. nov. (Peru), and Neosphenorhina schombergi sp. nov. (Brazil).
Resumo:
Novos registros e novas espécies de Hemilophini (Cerambycidae) coletados por pulverização de inseticida nas copas das árvores no Equador: Olivensa megacephala (Bates, 1866); Icupima laevipennis (Gahan, 1892); Hemilomecopterus alienus Galileo & Martins, 2004; Acapiata gen. nov., espécie-tipo A. dilatata sp. nov.; Acaiu gen. nov., espécie-tipo A. spinosus sp. nov.; Okamira gen. nov., espécie-tipo O. pulchra sp. nov. Duas espécies novas de Erana Bates, 1866 também são descritas: E. costaricensis sp. nov. da Costa Rica (Heredia) e E. flaviventris sp. nov. de Honduras (Yoro).
Resumo:
O gênero Willistoniella e a espécie-tipo W. pleuropunctata (Wiedemann, 1824), são redescritos. Três espécies novas, W. latiforceps sp. nov., W. spatulata sp. nov. e W. ulyssesi sp. nov., são descritas do Brasil (Amazonas). As quatro espécies são ilustradas e uma chave para espécies de Willistoniella é fornecida.