Three known pterocarpin derivatives, （-）-medicarpin （PDI）, （-）-2-hydroxy-4,9-dimethoxypterocarpan （PD2）, and 4- hydroxy-3-methoxy-8,9-methylene-dioxypterocarpan （PD3） were isolated from Canavalia maritima, f...Three known pterocarpin derivatives, （-）-medicarpin （PDI）, （-）-2-hydroxy-4,9-dimethoxypterocarpan （PD2）, and 4- hydroxy-3-methoxy-8,9-methylene-dioxypterocarpan （PD3） were isolated from Canavalia maritima, for the first time. The cytotoxic and pro-apoptotic activities of （-）-medicarpin in cutured human tumor HeLa cells and its effect on NF-r,B activation were investigated. We found that PD1 inhibited NF-r,B activation by high content screening analysis, and PD1 exhibited cytotoxicity by SRB assay. In addition, we found that PD1 induced nuclear condensation and increased membrane permeability and mitochondrial transmembrane potential in HeLa cells in a dose and time dependent manner. In conclusion, our data suggested that （- ）-medicarpin was capable of inhibiting tumor cell growth in vitro and inducing apoptosis, which might be via the suppression of NF-kB activation.展开更多
Bacteria form biofilms as an adaptive mechanism in response to environmental changes. Streptococcus mutans is the biofilm-forming bacterium that is primarily associated with dental caries. The expression of important ...Bacteria form biofilms as an adaptive mechanism in response to environmental changes. Streptococcus mutans is the biofilm-forming bacterium that is primarily associated with dental caries. The expression of important genes by bacteria in biofilms is different from that of planktonic cells. Lectins are proteins that bind specifically to carbohydrates and may have important biological activities on bacterial cells, acting as antibacterial and anti-biofilm agents. ConM (Canavalia maritima lectin) is a protein that is able to inhibit the planktonic growth and biofilm formation of S. mutans. In this context, this study aimed to evaluate the effects of ConM and concanavalin A (ConA) on the expression of genes related to virulence and biofilm formation in S. mutans. The results showed that ConM significantly reduced the expression of genes encoding enzymes related to adhesion, formation and regulation of biofilms. On the contrary, ConA did not alter the expression of the genes studied. Because the two lectins have a high degree of similarity, the differences in the actions of ConM and ConA may be explained by the small structural differences in the carbohydrate recognition domain of the lectins.展开更多
Small-scale crop production in many parts of Tanzania is constrained by many problems among which soil fertility degradation is a major problem. Over 80% of cassava (Manihot esculenta) production in Tanzania is done b...Small-scale crop production in many parts of Tanzania is constrained by many problems among which soil fertility degradation is a major problem. Over 80% of cassava (Manihot esculenta) production in Tanzania is done by the small-scale farmers who continuously cultivate their fields, but use limited inputs to restore depleted plant nutrients. The objective of this study was to examine the best legume species that could be incorporated in cassava (Manihot esculenta) production systems under farmers’ conditions and result in increase in soil fertility and crop yields. Mucuna pruriens and Canavalia ensiformis were either incorporated with cassava (Manihot esculenta) or planted as sole crop in rotation with cassava. Mucuna pruriens and Canavalia ensiformis were found to produce almost similar amount of biomass. The two legumes, however, produced higher biomass in rotation than intercropping system. The amount of biomass produced by Mucuna pruriens and Canavalia ensiformis in rotation system was 6.28 t·ha-1 and 5.31 t·ha-1, respectively. The Mucuna use represents an input of nitrogen into the soil which simulates a saving cost of 181.42 and 141.96 US$ ha-1. In the first year, cassava root yields were significantly increased (p < 0.05) over control (continuous sole cassava) (1.44 t·ha-1) by the use of intercropping of cassava (Manihot esculenta) with Mucuna pruriens (2.41 t·ha-1) and or Canavalia ensiformis (2.25 t·ha-1). Intercropping and rotation of cassava with legumes increase cassava yield and represent a sustainable alternative to reduce the farms’ dependence on external inputs and to enhance inherent soil fertility.展开更多
基金National High Technology Development Project (863 Project,Grants No.2006AA09Z446,2006AA09Z405 and 2006DFA31100)NSFC(Grants No.30672607,30901845)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministry.
文摘Three known pterocarpin derivatives, （-）-medicarpin （PDI）, （-）-2-hydroxy-4,9-dimethoxypterocarpan （PD2）, and 4- hydroxy-3-methoxy-8,9-methylene-dioxypterocarpan （PD3） were isolated from Canavalia maritima, for the first time. The cytotoxic and pro-apoptotic activities of （-）-medicarpin in cutured human tumor HeLa cells and its effect on NF-r,B activation were investigated. We found that PD1 inhibited NF-r,B activation by high content screening analysis, and PD1 exhibited cytotoxicity by SRB assay. In addition, we found that PD1 induced nuclear condensation and increased membrane permeability and mitochondrial transmembrane potential in HeLa cells in a dose and time dependent manner. In conclusion, our data suggested that （- ）-medicarpin was capable of inhibiting tumor cell growth in vitro and inducing apoptosis, which might be via the suppression of NF-kB activation.
文摘Bacteria form biofilms as an adaptive mechanism in response to environmental changes. Streptococcus mutans is the biofilm-forming bacterium that is primarily associated with dental caries. The expression of important genes by bacteria in biofilms is different from that of planktonic cells. Lectins are proteins that bind specifically to carbohydrates and may have important biological activities on bacterial cells, acting as antibacterial and anti-biofilm agents. ConM (Canavalia maritima lectin) is a protein that is able to inhibit the planktonic growth and biofilm formation of S. mutans. In this context, this study aimed to evaluate the effects of ConM and concanavalin A (ConA) on the expression of genes related to virulence and biofilm formation in S. mutans. The results showed that ConM significantly reduced the expression of genes encoding enzymes related to adhesion, formation and regulation of biofilms. On the contrary, ConA did not alter the expression of the genes studied. Because the two lectins have a high degree of similarity, the differences in the actions of ConM and ConA may be explained by the small structural differences in the carbohydrate recognition domain of the lectins.
文摘Small-scale crop production in many parts of Tanzania is constrained by many problems among which soil fertility degradation is a major problem. Over 80% of cassava (Manihot esculenta) production in Tanzania is done by the small-scale farmers who continuously cultivate their fields, but use limited inputs to restore depleted plant nutrients. The objective of this study was to examine the best legume species that could be incorporated in cassava (Manihot esculenta) production systems under farmers’ conditions and result in increase in soil fertility and crop yields. Mucuna pruriens and Canavalia ensiformis were either incorporated with cassava (Manihot esculenta) or planted as sole crop in rotation with cassava. Mucuna pruriens and Canavalia ensiformis were found to produce almost similar amount of biomass. The two legumes, however, produced higher biomass in rotation than intercropping system. The amount of biomass produced by Mucuna pruriens and Canavalia ensiformis in rotation system was 6.28 t·ha-1 and 5.31 t·ha-1, respectively. The Mucuna use represents an input of nitrogen into the soil which simulates a saving cost of 181.42 and 141.96 US$ ha-1. In the first year, cassava root yields were significantly increased (p < 0.05) over control (continuous sole cassava) (1.44 t·ha-1) by the use of intercropping of cassava (Manihot esculenta) with Mucuna pruriens (2.41 t·ha-1) and or Canavalia ensiformis (2.25 t·ha-1). Intercropping and rotation of cassava with legumes increase cassava yield and represent a sustainable alternative to reduce the farms’ dependence on external inputs and to enhance inherent soil fertility.
