RÉSUMÉ
Cell cultures of Mandevilla velutina have proved to be an interesting production system for biomass and secondary metabolites able to inhibit the hypotensive activity of bradykinin, a nonapeptide generated in plasma during tissue trauma. The crude ethyl acetate extract of cultured cells contains about 31- to 79-fold more potent anti-bradykinin compounds (e.g., velutinol A) than that obtained with equivalent extracts of tubers. Somaclonal variation may be an explanation for the wide range of inhibitor activity found in the cell cultures. The heterogeneity concerning morphology, differentiation, carbon dissimilation, and velutinol A production in M. velutina cell cultures is reported. Cell cultures showed an asynchronous growth and cells in distinct developmental stages. Meristematic cells were found as the major type, with several morphological variations. Cell aggregates consisting only of meristematic cells, differentiated cells containing specialized cell structures such as functional chloroplasts (cytodifferentiation) and cells with embryogenetic characteristics were observed. The time course for sucrose metabolism indicated cell populations with significant differences in growth and metabolic rates, with the highest biomass-producing cell line showing a cell cycle 60% shorter and a metabolic rate 33.6% higher than the control (F2 cell population). MALDI-TOF mass spectrometric analysis of velutinol A in selected cell lines demonstrated the existence of velutinol A producing and nonproducing somaclones. These results point to a high genetic heterogeneity in general and also in terms of secondary metabolite content.
Sujet(s)
Variation génétique/génétique , Extraits de plantes/composition chimique , Plantes médicinales/génétique , Bradykinine/antagonistes et inhibiteurs , Brésil , Techniques de culture cellulaire/méthodes , Lignée cellulaire , Chromatographie , Méristème/cytologie , Microscopie électronique à balayage , Phénotype , Extraits de plantes/métabolisme , Plantes médicinales/cytologie , Plantes médicinales/métabolisme , Spectrométrie de masse MALDI , Saccharose/métabolismeRÉSUMÉ
Cell cultures of Mandevilla velutina have proved to be an interesting production system for biomass and secondary metabolites able to inhibit the hypotensive activity of bradykinin, a nonapeptide generated in plasma during tissue trauma. The crude ethyl acetate extract of cultured cells contains about 31- to 79-fold more potent anti-bradykinin compounds (e.g., velutinol A) than that obtained with equivalent extracts of tubers. Somaclonal variation may be an explanation for the wide range of inhibitor activity found in the cell cultures. The heterogeneity concerning morphology, differentiation, carbon dissimilation, and velutinol A production in M. velutina cell cultures is reported. Cell cultures showed an asynchronous growth and cells in distinct developmental stages. Meristematic cells were found as the major type, with several morphological variations. Cell aggregates consisting only of meristematic cells, differentiated cells containing specialized cell structures such as functional chloroplasts (cytodifferentiation) and cells with embryogenetic characteristics were observed. The time course for sucrose metabolism indicated cell populations with significant differences in growth and metabolic rates, with the highest biomass-producing cell line showing a cell cycle 60 percent shorter and a metabolic rate 33.6 percent higher than the control (F2 cell population). MALDI-TOF mass spectrometric analysis of velutinol A in selected cell lines demonstrated the existence of velutinol A producing and nonproducing somaclones. These results point to a high genetic heterogeneity in general and also in terms of secondary metabolite content
Sujet(s)
Variation génétique , Extraits de plantes , Plantes médicinales , Brésil , Techniques de culture cellulaire , Lignée cellulaire , Chromatographie , Méristème , Microscopie électronique à balayage , Phénotype , Extraits de plantes , Plantes médicinales , Spectrométrie de masse MALDI , SaccharoseRÉSUMÉ
A procedure for the purification of a Peruvian isolate (C1) of sweet potato feathery mottle potyvirus (SPFMV) and infective RNA has been developed. The use of Hepes [N-(2-hydroxyethyl)piperazine-N'-2-ethanesulfonic acid] buffer containing urea and sodium EDTA as a base for tissue extraction and virus suspension enabled good yields of virus (35-50 mg/100 g) to be obtained from Nicotiana benthamiana L. Domin. A short RNA isolation procedure yielded infectious RNA, from which ds cDNA of nearly genome size could be obtained. Sweet potato feathery mottle potyvirus, Purification, RNA isolation, cDNA synthesis.