RESUMO
Quatro diferentes sistemas de modelos de produção de plantas medicinais na região metropolitana de Curitiba, Paraná, foram estudados. O objetivo do estudo foi analisar os diferentes modelos com uma aproximação holística (sob foco sistêmico) pretendendo, como o resultado final, um sistema de produção alternativo, tecnicamente, economicamente e ambientalmente sustentável. Vários aspectos de qualidade foram especialmente analisados. O trabalho foi desenvolvido durante setembro de 2000 a maio de 2001, usando um levantamento rápido em áreas rurais, com entrevistas semi-estruturadas.
Four different medicinal plant production system models in Curitiba Metropolitan Area, Paraná, were studied. The objective of the study was to analyze the different models with a holistic approach (under systemic focus) intending, as the end result, an alternative technically, economically, and environmentally sustainable production system. Several aspects of quality were especially analyzed. The work was developed during September 2000 to May 2001, using a quick survey in rural areas, with semi-structured interviews.
RESUMO
The effects of methotrexate (MTX) on oxygen uptake by permeabilized HeLa cells were evaluated. MTX did not inhibit state III respiration when the oxidizable substrate was succinate, but when the substrates were 2-oxoglutarate or isocitrate the respiration decreased about 50 per cent at 1.0 mM concentration of the drug. This effect was explained by inhibition of 2-oxoglutarate and isocitrate dehydrogenases by MTX. No effect was observed on succinate dehydrogenase. An evaluation of the effects of MTX on malic enzyme activity as measured by pyruvate plus lactate production in intact cells supplied with malate showed a decrease of about 40 per cent in metabolite production using 0.4 mM MTX. HeLa cell malic enzyme, as observed for other tumour cells, is compartmentalized in mitochondria and cytosol, and is another example of a dehydrogenase inhibited by MTX.
Assuntos
Antimetabólitos Antineoplásicos/farmacologia , Metotrexato/farmacologia , Oxirredutases/metabolismo , Células HeLa , Humanos , Isocitrato Desidrogenase/metabolismo , Complexo Cetoglutarato Desidrogenase/metabolismo , Ácido Láctico/metabolismo , Malato Desidrogenase/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/enzimologia , NADPH Desidrogenase/metabolismo , Consumo de Oxigênio/efeitos dos fármacos , Ácido Pirúvico/metabolismoRESUMO
1. We studied mitochondria of digitonin-permeabilized HeLa cells, since digitonin (60 micrograms/10(6) cells) increases plasma membrane Ca2+ permeability, in order to avoid problems such as low mitochondrial yield and the possibility of obtaining damaged or uncoupled mitochondria from tumor cells. 2. Addition of Ca2+ to digitonin-permeabilized HeLa cells gave rise to a cycle of respiratory stimulation. Ca2+ uptake was almost totally inhibited by antimycin A (6.0 micrograms/ml). 3. Ca2+ release occurred upon addition of carbonyl cyanide p-trifluoromethoxy-phenylhydrazone (FCCP) to digitonin-permeabilized HeLa cells, under steady-state conditions. An antimycin A- and FCCP-insensitive Ca2+ uptake was also detected in this preparation when ATP was added, which reflects Ca2+ capture by other organelles. 4. The characteristics of the mitochondrial Ca2+ transport system in HeLa cells are similar to those of other previously studied tumor cells. Mitochondria from HeLa cells are resistant to the deleterious effects of massive Ca2+ loads.
Assuntos
Cálcio/metabolismo , Células HeLa/metabolismo , Mitocôndrias/metabolismo , Transporte Biológico/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Digitonina/farmacologia , Feminino , Células HeLa/ultraestrutura , Humanos , Membranas Intracelulares/efeitos dos fármacos , Membranas Intracelulares/metabolismo , Mitocôndrias/efeitos dos fármacos , Consumo de Oxigênio/efeitos dos fármacosRESUMO
We studied mitochondria of digitonin-permeabilized Hela cells, since digitonin (60 ug/10 6 cells) increases plasma membrane Ca2+ permeability, in order to avoid problems such as low mitochondrial yield and the possibility of obtaining damaged or uncoupled mitochondria from tumor cells. Addition of Ca2+ to digitonin-permeabilized Hela cells gave rise to a cycle of respiratory stimulation. Ca2+ uptake was almost totally inhibited by antimycin A (6.0 ug/ml). Ca2+ release occurred upon addition of carbonyl cyanide p-trifluoromethoxy-phenylhydrazone (FCCP) to digitonin-permeabilized Hela cells, under state conditions. An antimycin A-and FCCP-insensitive Ca2+ uptake was also detected in this preparation when ATP was added, which reflects Ca2+ capture by other organelles. The characteristics of the mitochondrial Ca2+ transport system in Hela cells are similar to those of other previously studied tumor cells. Mitochondria from Hela cells are resistant to the deleterious effects of massive Ca2+ loads