AIM： To investigate the potential effects of chelidonine, the main alkaloid of Chelidonium majus, on telomerase activity and its regulation in HepG2 cells. METHODS： Cytotoxicity of chelidonine for HepG2 cells was de...AIM： To investigate the potential effects of chelidonine, the main alkaloid of Chelidonium majus, on telomerase activity and its regulation in HepG2 cells. METHODS： Cytotoxicity of chelidonine for HepG2 cells was determined by neutral red assay. A modified polymerase chain reaction （PCR）-based telomerase repeat amplification protocol was used to estimate relative telomerase activity in chelidonine-treated cells in comparison with the untreated control cells. Relative expression level of the catalytic subunit of telomerase （hTERT） gene and P-glycoprotein （pgp） were estimated using semi-quantitative real-time reverse transcription-PCR （RT-PCR）. Cell senescence in treated cells was demonstrated using a 13-galactosidase test. RESULTS： Cytotoxicity of chelidonine in HepG2 cells was not dose-dependent and tended to reach plateau immediately after the living cells were reduced in number to slightly higher than 50%. However, 12 μmol/L concentration of chelidonine was considered as LD50, where the maximal attainable effects were realized. Real-time RT-PCR data showed that the expression of pgp increased three-fold in chelidonine treated HepG2 cells in comparison with the untreated controls. MoP phologically, treated HepG2 cells showed apoptotic features after 24 h and a small fraction of cells appeared with single blister cell death. The relative expression level of Bcl-2 dropped to less than 50% of control cells at a sub-apoptotic concentration of chelidonine and subsequently increased to higher than 120% at LD50. Telomerase activity was reduced considerably after administration of very low doses of chelidonine, whereas higher concentrations of chelidonine did not remarkably enhance the effect. Real-time RT-PCR experiments indicated a drastic decrease in expression level of hTERT subunit of telomerase under treatment with chelidonine. Repeated treatment of cells with very low doses of chelidonine caused a decline in growth rate by 4 wk and many of the cells appeared to be aged with large volume and dark staining in the β-galactosidase assay. CONCLUSION： Chelidonine reduces telomerase activity through down-regulation of hTERT expression. Senescence induction might not be directly caused by reducing telomerase activity as it occurs after a few population doublings.展开更多
The purpose of the present studies was analysis of the age induced changes in photochemical efficiency and xanthophyils cycle pigments of the primary cabbage （Brassica oleracea L. cv. Capitata f. alba） leaves. Photo...The purpose of the present studies was analysis of the age induced changes in photochemical efficiency and xanthophyils cycle pigments of the primary cabbage （Brassica oleracea L. cv. Capitata f. alba） leaves. Photochemical efficiency of photosystem Ⅱ （PS Ⅱ） was studied by a pulse amplitude modulated chlorophyll fluorescence apparatus, chlorophyll concentration was analysis spectrophotometrically and xanthophyll cycle pigments were estimated by high-pressure liquid chromatography （HPLC）. Leaf senescence was accompanied with a decrease both in chlorophylls concentration, the photochemical efficiency and rate constant for PS Ⅱ photochemistry whereas non-photochemical parameters increased. Excitation pressure （1-qP） which is a measure of relative lumen acidification increased by 1.2x in aging leaves. The maximum quantum yield of PS Ⅱ showed no significant change. The level of de-epoxidised xanthophylls increased but the concentration of mono- and di-epoxy xanthophylls decreased in aging leaves. A linear relationship between the excitation pressure and the depoxidation state of the xanthophyll cycle pigments and lutein, during the onset of senescence suggests that excitation pressure can be used as a sensor for monitoring the onset of senescence as well for the de-epoxidation state of the xanthophylls responsible for non-photochemical quenching in stressed leaves.展开更多
The aim of the research was to connect two methods of the chemical control. The first chemical treatments were applied according to the signalling method. The second method was applied according to the phonological cr...The aim of the research was to connect two methods of the chemical control. The first chemical treatments were applied according to the signalling method. The second method was applied according to the phonological criterion i.e., on the basis of the values of effective temperatures sums or heat sums for cutworms. The studies on cutworms infesting sugar beet crops were carried out in the years 2005-2008. The observation performed during the moth flights from May to September included two species, turnip moth （Agrotis segetum Den. ＆ Schiff.） and heart-and-dart moth （A. exclamationis L.）. The dynamics of moth flights was recorded in reference to readings of climatic conditions registered with the field meteorological stations set up near the light traps. Observations on cutworm occurrence during the vegetation season were done every 5-7 days. Moreover, additional studies were conducted under control conditions in the growth chambers at three programmed temperatures （17°C, 20 °C, 24 °C） and relative humidity （50%-70%）. Based on the results the values for the heat sum of 501.1 °C and effective temperatures sum of 230.0 °C were determined for the developmental stages of cutworm. On the base of the results obtained it can be stated that the improved method of short-term forecasting can be an alternative solution in the integrated protection management against pest.展开更多
Information on seed vigor of the vegetable crops is always important and necessary due to the increasing demand of high quality seeds for sowing and high-value commercial. The cultivation of these species, conducted i...Information on seed vigor of the vegetable crops is always important and necessary due to the increasing demand of high quality seeds for sowing and high-value commercial. The cultivation of these species, conducted intensively, should be established with seed high potential physiological and health for the development of a more productive and sustainable agriculture. The present study was conducted to evaluate the potential physiological of seed lots of radish and coriander. The experiment was conducted at the laboratory of seed analysis and greenhouse of the plant science department of the Federal University of Pelotas in South Brazil. Four radish seed lots, cultivar ＂Saxa＂, and four coriander seed lots, cultivar ＂Verdito＂ were used. Germination seed test, first count of germination, accelerated aging test, electrical conductivity and seedling emergence were used to evaluate the physiological quality of the lots. The experimental design was completely randomized design with five replications. Means were compared by Tukey test. The accelerated aging test was the most efficient test in assessing the physiological quality for both lots of radish seeds and coriander and this test provide coherent results with seedlings emergence.展开更多
文摘AIM： To investigate the potential effects of chelidonine, the main alkaloid of Chelidonium majus, on telomerase activity and its regulation in HepG2 cells. METHODS： Cytotoxicity of chelidonine for HepG2 cells was determined by neutral red assay. A modified polymerase chain reaction （PCR）-based telomerase repeat amplification protocol was used to estimate relative telomerase activity in chelidonine-treated cells in comparison with the untreated control cells. Relative expression level of the catalytic subunit of telomerase （hTERT） gene and P-glycoprotein （pgp） were estimated using semi-quantitative real-time reverse transcription-PCR （RT-PCR）. Cell senescence in treated cells was demonstrated using a 13-galactosidase test. RESULTS： Cytotoxicity of chelidonine in HepG2 cells was not dose-dependent and tended to reach plateau immediately after the living cells were reduced in number to slightly higher than 50%. However, 12 μmol/L concentration of chelidonine was considered as LD50, where the maximal attainable effects were realized. Real-time RT-PCR data showed that the expression of pgp increased three-fold in chelidonine treated HepG2 cells in comparison with the untreated controls. MoP phologically, treated HepG2 cells showed apoptotic features after 24 h and a small fraction of cells appeared with single blister cell death. The relative expression level of Bcl-2 dropped to less than 50% of control cells at a sub-apoptotic concentration of chelidonine and subsequently increased to higher than 120% at LD50. Telomerase activity was reduced considerably after administration of very low doses of chelidonine, whereas higher concentrations of chelidonine did not remarkably enhance the effect. Real-time RT-PCR experiments indicated a drastic decrease in expression level of hTERT subunit of telomerase under treatment with chelidonine. Repeated treatment of cells with very low doses of chelidonine caused a decline in growth rate by 4 wk and many of the cells appeared to be aged with large volume and dark staining in the β-galactosidase assay. CONCLUSION： Chelidonine reduces telomerase activity through down-regulation of hTERT expression. Senescence induction might not be directly caused by reducing telomerase activity as it occurs after a few population doublings.
文摘The purpose of the present studies was analysis of the age induced changes in photochemical efficiency and xanthophyils cycle pigments of the primary cabbage （Brassica oleracea L. cv. Capitata f. alba） leaves. Photochemical efficiency of photosystem Ⅱ （PS Ⅱ） was studied by a pulse amplitude modulated chlorophyll fluorescence apparatus, chlorophyll concentration was analysis spectrophotometrically and xanthophyll cycle pigments were estimated by high-pressure liquid chromatography （HPLC）. Leaf senescence was accompanied with a decrease both in chlorophylls concentration, the photochemical efficiency and rate constant for PS Ⅱ photochemistry whereas non-photochemical parameters increased. Excitation pressure （1-qP） which is a measure of relative lumen acidification increased by 1.2x in aging leaves. The maximum quantum yield of PS Ⅱ showed no significant change. The level of de-epoxidised xanthophylls increased but the concentration of mono- and di-epoxy xanthophylls decreased in aging leaves. A linear relationship between the excitation pressure and the depoxidation state of the xanthophyll cycle pigments and lutein, during the onset of senescence suggests that excitation pressure can be used as a sensor for monitoring the onset of senescence as well for the de-epoxidation state of the xanthophylls responsible for non-photochemical quenching in stressed leaves.
文摘The aim of the research was to connect two methods of the chemical control. The first chemical treatments were applied according to the signalling method. The second method was applied according to the phonological criterion i.e., on the basis of the values of effective temperatures sums or heat sums for cutworms. The studies on cutworms infesting sugar beet crops were carried out in the years 2005-2008. The observation performed during the moth flights from May to September included two species, turnip moth （Agrotis segetum Den. ＆ Schiff.） and heart-and-dart moth （A. exclamationis L.）. The dynamics of moth flights was recorded in reference to readings of climatic conditions registered with the field meteorological stations set up near the light traps. Observations on cutworm occurrence during the vegetation season were done every 5-7 days. Moreover, additional studies were conducted under control conditions in the growth chambers at three programmed temperatures （17°C, 20 °C, 24 °C） and relative humidity （50%-70%）. Based on the results the values for the heat sum of 501.1 °C and effective temperatures sum of 230.0 °C were determined for the developmental stages of cutworm. On the base of the results obtained it can be stated that the improved method of short-term forecasting can be an alternative solution in the integrated protection management against pest.
文摘Information on seed vigor of the vegetable crops is always important and necessary due to the increasing demand of high quality seeds for sowing and high-value commercial. The cultivation of these species, conducted intensively, should be established with seed high potential physiological and health for the development of a more productive and sustainable agriculture. The present study was conducted to evaluate the potential physiological of seed lots of radish and coriander. The experiment was conducted at the laboratory of seed analysis and greenhouse of the plant science department of the Federal University of Pelotas in South Brazil. Four radish seed lots, cultivar ＂Saxa＂, and four coriander seed lots, cultivar ＂Verdito＂ were used. Germination seed test, first count of germination, accelerated aging test, electrical conductivity and seedling emergence were used to evaluate the physiological quality of the lots. The experimental design was completely randomized design with five replications. Means were compared by Tukey test. The accelerated aging test was the most efficient test in assessing the physiological quality for both lots of radish seeds and coriander and this test provide coherent results with seedlings emergence.
