Produção de metabólitos bioativos pelo líquen Cladonia substellata Vainio Production of bioactive metabolites from lichen Cladonia substellata Vainio

Objetivando comparar a atividade antimicrobiana de extratos brutos de Cladonia substellata, proveniente dos Estados de Minas Gerais e Pará, Brasil, utilizou-se o método de difusão em meio sólido. Extratos etéreo, clorofórmico e acetônico foram testados contra patógenos humanos e fitopatógenos na concentração de 1,0 mg/mL, 0,1 mg/mL e 0,01 mg/mL. Os extratos foram submetidos à cromatografia em camada delgada, e o princípio ativo atribuído através de biocromatografia. Os resultados demonstraram que as sete espécies de fungos testadas foram resistentes aos extratos de C. substellata procedente do Pará, porém, quatro destas espécies mostraram-se sensíveis aos extratos etéreo e clorofórmico da amostra de Minas Gerais. Todos os extratos foram ativos contra as mesmas espécies de bactérias, entretanto os extratos da amostra procedente de Minas Gerais demonstraram melhor atividade. Das bactérias inibidas, Staphylococcus aureus mostrou-se a menos sensível, ao contrário das fitopatógenas que apresentaram grande sensibilidade. Os testes cromatográficos revelaram a presença de ácido úsnico em todos os extratos, porém, em maior quantidade na amostra do Pará. O biocromatograma revelou este ácido como princípio ativo da espécie, além de sua ação sinérgica com o ácido norestíctico, na amostra de Minas Gerais, justificando sua maior atividade.<br>This work purposed to make a comparison between antimicrobial activity of crude extracts from Cladonia substellata, collected at Minas Gerais and Pará States, Brazil, using the diffusion solid medium methods. Ether, chloroform, and acetone extracts, at 1 mg/mL, 0.1 mg/mL, and 0.01 mg/mL, were tested against human pathogens and phytopathogens. The extracts were submitted to thin layer chromatography and their active principles attributed by biochromatography. The results demonstrated that the seven fungi species tested were no sensitive to extracts from C. substellata from Pará. On the other hand, four of these microorganisms were inhibited by C. substellata extracts from Minas Gerais. All extracts were active to the same bacteria species, but samples from Minas Gerais showed the highest activity. Among the inhibited bacteria Staphylococcus aureus was the less sensitive, with an opposite behavior to phytopathogen ones, that showed the highest sensitivity. Chromatographic assays revealed the presence of usnic acid in all extracts, thus in the most content in Pará samples. The biochromatograms reveals usnic acid as active principle of the species, and a synergic action to norstictic acid found in Minas Gerais samples, what justify its highest activity

DNA-based vaccines protect against zoonotic schistosomiasis in water buffalo

Schistosomiasis japonica is an endemic, zoonotic disease of major public health importance in China where water buffaloes account for approximately 75% of disease transmission. Interventions that reduce schistosome infection in water buffaloes will enhance their health simultaneously reducing disease transmission to humans. While chemotherapy has proved successful, it requires continued time consuming and expensive mass treatments. A more sustainable option would be development of vaccines that reduce transmission of S. japonicum from bovines to replace bovine chemotherapy. We performed two randomized double blind trials in water buffaloes to determine if DNA vaccines encoding triose-phosphate isomerase (SjCTPI), or the tetraspanin 23 kDa integral membrane protein (SjC23), alone or fused to bovine heat shock protein 70 (Hsp70) could induce a level of immunity conducive to long-term sustainable control. Groups of water buffaloes (15/group) received three intramuscular injections, 4 weeks apart. Booster immunizations were co-administered with a plasmid DNA encoding IL-12. Four weeks after the last injection, water buffaloes were challenged with 1000 cercariae, and vaccine efficacy analyzed 8 weeks later. Water buffaloes vaccinated with SjCTPI-Hsp70 or SjCTPI plasmids had worm burdens reduced by 51.2% and 41.5%, respectively. Importantly, fecal miracidial hatching was reduced by 52.1% and 33.2% respectively compared to control vaccinated water buffaloes. Vaccination with SjC23-Hsp70 and SjC23 plasmids reduced worm burdens by 50.9% and 45.5%, respectively, and fecal miracidial hatching by 52.0% and 47.4%. A mathematical model of schistosome transmission predicts that schistosome vaccines capable of reducing water buffaloes’ fecal egg output by 45%, alone or in conjunction with praziquantel treatment, will lead to a significant reduction in transmission of schistosomiasis. Both DNA vaccines tested here exceed this hypothetical level. Indeed, mathematical modeling of SjCTPI-Hsp70 and SjC23-Hsp70 alone and in conjunction with human chemotherapy showed a significant reduction in transmission almost to the point of elimination