219 research outputs found
Soil organisms in organic and conventional cropping systems.
Apesar do crescente interesse pela agricultura orgĂąnica, sĂŁo poucas as informaçÔes de pesquisa disponĂveis sobre o assunto. Assim, num Argissolo Vermelho-Amarelo distrĂłfico foram comparados os efeitos de sistemas de cultivo orgĂąnico e convencional, para as culturas do tomate (Lycopersicum esculentum) e do milho (Zea mays), sobre a comunidade de organismos do solo e suas atividades. As populaçÔes de fungos,bactĂ©rias e actinomicetos, determinadas pela contagem de colĂŽnias em meio de cultura, foram semelhantes para os dois sistemas de produção. A atividade microbiana, avaliada pela evolução de CO2, manteve-se superior no sistema orgĂąnico, sendo que em determinadas avaliaçÔes foi o dobro da evolução verificada no sistema convencional. O nĂșmero de espĂ©cimes de minhoca foi praticamente dez vezes maior no sistema orgĂąnico. NĂŁo foi observada diferença na taxa de decomposição de matĂ©ria orgĂąnica entre os dois sistemas. De modo geral, o nĂșmero de indivĂduos de microartrĂłpodos foi superior no sistema orgĂąnico do que no sistema convencional, refletindo no maior Ăndice de diversidade de Shannon. As maiores populaçÔes de insetos foram as da ordem Collembola, enquanto para os ĂĄcaros a maior população foi a da superfamĂlia Oribatuloidea. IndivĂduos dos grupos Aranae, Chilopoda, Dyplopoda, Pauropoda, Protura e Symphyla foram ocasionalmente coletados e de forma similar entre os sistemas
Essential oil from Ageratum fastigiatum reduces expression of the pro-inflammatory cytokine tumor necrosis factor-alpha in peripheral blood leukocytes subjected to in vitro stimulation with phorbol myristate acetate
AbstractAgeratum fastigiatum (Gardner) R.M. King & H. Rob., a member of the Asteraceae family popularly known in Brazil as âmatapastoâ, is indicated in folk medicine as anti-inflammatory and analgesic. Despite its popular use, little is known about its potential effect on the parameters involved in an inflammatory response. The objective of this study was to characterize the chemical composition of the essential oil from A. fastigiatum and to evaluate the frequency of tumor necrosis factor alpha and interferon gamma producing cells in peripheral blood lymphocytes stimulated with phorbol myristate acetate in the presence of essential oil from A. fastigiatum. Non-toxic concentrations of essential oil from A. fastigiatum were evaluated in cultures of peripheral blood leucocytes using the trypan blue exclusion assay by flow cytometry. GCâMS analysis revealed that the prevalent compounds identified in the essential oil from A. fastigiatum sample were α-pinene, limonene, trans-caryophyllene, α-humulene, caryophyllene oxide, 1,2-humulene-epoxide, 1,6-humulanodien-3-ol, and α-cadinol. Results showed that exposure to essential oil from A. fastigiatum at concentrations of 0.5Ă10â2 and 1Ă10â2ÎŒl/ml caused no alterations in leukocyte viability as compared to the control group. Both concentrations lowered the percentage of tumor necrosis factor alpha (+)-lymphocytes and neutrophils. There were no changes in the percentage of lymphocytes positive for the interferon gamma cytokine. Our results suggest that part of the anti-inflammatory activity attributed to A. fastigiatum may be due to the effect of some of its components in decreasing the number of cells that produce the pro-inflammatory cytokine tumor necrosis factor alpha
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