Various Leishmania species were engineered with green fluorescent protein (GFP) using episomal vectors that encoded an antibiotic resistance gene, such as aminoglycoside geneticin sulphate (G418). Most reports of GFP-Leishmania have used the flagellated extracellular promastigote, the stage of parasite detected in the midgut of the sandfly vector; fewer studies have been performed with amastigotes, the stage of parasite detected in mammals. In this study, comparisons were made regarding the efficiency for in vitro G418 selection of GFP-Leishmania amazonensis promastigotes and amastigotes and the use of in vivo G418 selection. The GFP-promastigotes retained episomal plasmid for a prolonged period and G418 treatment was necessary and efficient for in vitro selection. In contrast, GFP-amastigotes showed low retention of the episomal plasmid in the absence of G418 selection and low sensitivity to antibiotics in vitro. The use of protocols for G418 selection using infected BALB/c mice also indicated low sensitivity to antibiotics against amastigotes in cutaneous lesions.
NEW OCCURRENCES OF URANIUM IN THE LAGOA REAL REGION USING A GEOPHYSICAL, GEOLOGICAL AND REMOTE SENSING SUPPERPOSITION The origin and control of Uranium occurrences and deposits at the Uraniferous District of Lagoa Real, State of Bahia (Brazil), has been largely studied over the last decades. Currently, the deposit controls are bounded to albitites in the Granite-Gneissic Complex at the center-south area of Lagoa Real. Data from the São Timóteo Airborne Geophysical Project have been analyzed and superimposed to geological, geophysical and remote sensing data in order to identify new occurrences of Uranium for prospection. Reappraisal of the gammaspectrometric data (K, U e Th) shows that distinctive litotypes indicate some radiometric anomalies in the northeast area. The magnetometric data suggest the existence of depth-rooted magnetic blocks separated by shear zones recognized by the Landsat-5TM's image. The combination of these products with the geological information shows a structural evolution not previously described in literature. The kinematics of the shear zones with N-S, NE-SW and NE-SW directions was established based on bodies´ displacement and magnetic features. The ductile-ruptile, ruptileductile and ruptile structures are compatible with the geological framework of the São Francisco Craton during the Brazilian Cicle: East-West convergence with West mass transport. The continuing deformation produced dextral and sinistral shear zones that resulted in the inflection of the pre-existent foliation. The well-known Uranium deposits are located in the N-S shear zones; the new occurrences, located in the northeastern area, are associated with the NW-SE shear zones and they introduce new targets for prospection. Keywords: airborne geophysics, geology, remote sensing, São Timóteo ProjectResumo O Distrito Uranífero de Lagoa Real, no estado da Bahia, tem sido alvo de diversos estudos sobre a origem e o controle das ocorrências de Urânio, no decorrer das últimas décadas. Atualmente, o controle dos depósitos restringe-se aos albititos do Complexo Granito-Gnáissico localizados na porção centro-sul em Lagoa Real. Os dados do Projeto Aerogeofísico São Timóteo foram analisados e superpostos aos dados geológicos e de sensoriamento remoto, com o objetivo de identificar novas ocorrências promissoras à prospecção de Urânio. Com a reavaliação de dados gamaespectrométricos (K, U, Th), distintos litotipos evidenciam áreas com anomalias radiométricas no setor nordeste. Os dados magnetométricos mostram blocos magnéticos distintos, de natureza profunda, que estão compartimentados por zonas de cisalhamento reconhecidas em imagens Landsat-5/TM. A integração desses produtos com as informações geológicas disponíveis evidenciam um quadro geológico-estrutural até então não descrito na literatura. A cinemática de zonas de cisalhamento com direções N-S, NE-SW e NW-SE foi estabelecida a partir de deslocamentos de corpos e feições magnéticas. As estruturas dúctil-rúptil, rúptil-dúctil e rúptil observadas também são compatíveis ...
The 70 kDa heat shock protein (HSP70) is a molecular chaperone that assists the parasite Leishmania in returning to homeostasis after being subjected to different types of stress during its life cycle. In the present study, we evaluated the effects of HSP70 transfection of L. amazonensis promastigotes (pTEX-HSP70) in terms of morphology, resistance, infectivity and mitochondrial bioenergetics. The pTEX-HSP70 promastigotes showed no ultrastructural morphological changes compared to control parasites. Interestingly, the pTEX-HSP70 promastigotes are resistant to heat shock, H2O2-induced oxidative stress and hyperbaric environments. Regarding the bioenergetics parameters, the pTEX-HSP70 parasites had higher respiratory rates and released less H2O2 than the control parasites. Nevertheless, the infectivity capacity of the parasites did not change, as verified by the infection of murine peritoneal macrophages and human macrophages, as well as the infection of BALB/c mice. Together, these results indicate that the overexpression of HSP70 protects L. amazonensis from stress, but does not interfere with its infective capacity.
Resveratrol, echinomycin and CdCl2 reduce parasite survival in vitro. The HIF-1α targeting pharmacological drugs require further study to more fully determine their anti-Leishmania potential and their role in therapeutic strategies.
A utilização de técnicas e métodos geofísicos nas geociências, para estudos de superfície e subsuperfície na região amazônica, pode contribuir para o desenvolvimento substancial do conhecimento sobre a geometria e disposição tridimensional das camadas de rocha nos intervalos de rochas localizadas a centenas de metros de profundidade dessa grande área, ainda pouco explorada. A integração de dados de superfície e de subsuperfície, abrange análises geológicas de estruturas em superfície, feições geomorfológicas ainda não identificadas e descritas na área. Neste estudo, o uso de seções sísmicas e de perfis de poço possibilitou a geração de um modelo geológico em profundidade. As evidências geomorfológicas e tectono-estratigráficas descritas na área foram obtidas a partir da avaliação sismoestrutural (falhas e dobras) e as sismoestratigráfica (canais, preenchimentos de canais, barras, vales, erosões e adelgaçamento de camadas). Com base nessas evidências, foi sugerida a ocorrência de feições associadas a cânions de diferente porte e vales, oriundos da reativação rúptil de estruturas preexistentes no embasamento Pré-cambriano. Além disso, também são encontradas evidências de sedimentação resultante da acreção lateral, erosão e adelgaçamento, influenciados por processos de subsidência e isostasia. As sequências sedimentares estabelecidas neste arcabouço são pertencentes a depósitos com idades do Paleógeno até o Quaternário ou recente. Estas evidências podem estar relacionadas com a evolução do Alto do Vaupés, que ocorre devido a falhamentos do paleozóico inferior, que sofreram reativação durante o paleógeno até o recente, com episódios tectonoestratigráficos associados.
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