Neolignans from plants in northeastern Brazil (Lauraceae) with activity against Trypanosoma cruzi.

Trypanosoma cruzi is the ethiological agent for Chagas disease in Latin America. This study aimed to test the trypanocidal effect of licarin A and burchellin isolated from plants in northeastern Brazil. These neolignans were tested on T. cruzi and on peritoneal macrophages, to evaluate drug toxicity. Epimastigote growth was inhibited in 45% with licarin A and 20% with burchellin with an IC(50)/96 h of 462.7 microM and 756 microM, respectively. Epimastigotes treated with licarin A presented swollen mitochondria and disorganized mitochondrial cristae, kDNA and Golgi complex. When treated with burchellin, they presented enormous autophagosomes and chromatin disorganization. Licarin A and burchellin were able to induce trypomastigote death with IC(50)/24 h of 960 microM and 520 microM, respectively. Although licarin A presented an IC(50) for trypomastigotes higher than for epimastigotes, both substances acted as therapeutic trypanocidal agents, because they were able to kill parasites without affecting macrophages. Due to our results, burchellin and licarin A need to be further analysed to observe if they may be used as alternative blood additive prophylaxis against Chagas disease, since it has been established that blood transfusion is an important mechanism in the transmission process.

Biological activity of neolignans on the post-embryonic development of Chrysomya megacephala.

Phytochemicals endowed with hormonal, antihormonal, or toxic activity are potential agents for insect control. The effect of some neolignans on one of the most prevalent flies in urban areas, which constitutes a menace to public health, was investigated.

Análise da distribuição da região dos ferimentos provocados por morcegos hematófagos Desmodus rotundus (Geoffroy, 1810) em bovinos sob condições de campo / Topographic analysis of wounds caused by the vampire bat Desmodus rotundus (Geoffroy, 1810) in cattle under field conditions

Existem diversas espécies de morcegos no Brasil, sendo somente três hematófagas. O morcego Desmodus rotundus (Geoffroy, 1810), conhecido como "morcego vampiro comum", apresenta-se amplamente distribuído por todo território brasileiro e é encontrado em maior número do que as outras espécies de morcegos hematófagos. É responsável pela transmissão de diferentes doenças a outros mamíferos, especialmente a raiva nos herbívoros. Com o objetivo de avaliar regionalmente os ferimentos causados pelo D. rotundus em bovinos sob condições de campo, foram estudadas 12 propriedades rurais no período de março de 2005 a março de 2006 no Município de Valença, RJ. De um total de 580 bovinos examinados, foram observados 101 com ferimentos provocados por morcegos hematófagos (D. rotundus). Após análise dos resultados, pôde-se concluir que D. rotundus utiliza diferentes locais para se alimentar nos bovinos e as regiões corporais que apresentaram maior número de ferimentos foram a ântero e a póstero-superior. O elevado número de ferimentos encontrados, na metade superior dos bovinos (85,87%), justifica a adoção de metodologias de controle populacional de morcegos hematófagos que utilizem o contato corporal desses morcegos com o dorso do animal.

Brazil possesses a large amount of bat species, only 3 of which are haematophagous. The most abundant species, Desmodus rotundus (Geoffroy, 1810), is widely distributed throughout the Brazilian territory and it is involved in the transmission of several diseases to other animals, notably to herbivorous species, in the case of rabies. This study presents the topographical analysis of wounds caused by D. rotundus in bovines from 12 different rural properties in the county of Valença, state of Rio de Janeiro, where 101 bovines out of 580 examined in a year showed wounds caused by haematophagous bats. Analysis of the results leads to the conclusion that D. rotundus uses different sites to feed from the bovine's body and that the superior body region was the most frequently used. The increased number of wounds found in the bovine's superior half region (85.87%) will justify the use of bat population control methodologies which take into consideration the bat's corporal contact with the dorsal region of bovines.

Dynamic development of Trypanosoma cruzi in Rhodnius prolixus: role of decapitation and ecdysone therapy.

Decapitation and ecdysone therapy on the population dynamics of the Trypanosoma cruzi Dm28c clone in the stomach, small intestine and rectum of fifth-instar larvae of Rhodnius prolixus were investigated. Parasites were not found in the small intestine and rectum of decapitated insects after 10 days post-infection (p.i.). Decapitated ecdysone-supplemented insects sustained the flagellate infection in both gut compartments. In the rectum, the population density of parasites increased 5-fold in ecdysone-treated decapitated larvae and 7-fold in control insects. Epimastigote forms dominated with 40-65%, intermediate stages and round forms varied over 10-35% in the stomach, small intestine and rectum in both insect groups. Low numbers of metacyclic trypomastigotes were observed in the stomach and small intestine of the control group and decapitated insects supplemented with ecdysone but, at 15 days p.i., this form of flagellate reached about 20% in the rectum of the control insects. In the entire gut, at 30 days p.i., 23% of parasites in the control group and 8% in the decapitated insects treated with ecdysone were found. These results indicate that a head factor, possibly the prothoracicotropic hormone from the brain which stimulates ecdysone production by the prothoracic glands, may act directly or indirectly to stimulate the development of epimastigotes and round forms of the parasite and that a single ecdysone treatment is not able to fully reverse metacyclogenesis in decapitated R. prolixus.