Depolymerization of agar was performed using agarase, which was extracted from the cell-free medium of a culture of marine bacterial Alterornonas sp. nov. SY 37-12. After ethanol fractionation and lyophilization, the ...Depolymerization of agar was performed using agarase, which was extracted from the cell-free medium of a culture of marine bacterial Alterornonas sp. nov. SY 37-12. After ethanol fractionation and lyophilization, the water-soluble agar polysaccharide （WSAP3） was collected. The anti-tumor activity of the product was determined by using Sarcoma 180 tumor in mouse. The tumor inhibition rate of WSAP3 the product was determined by using Sarcoma 180 tumor in mouse. The tumor inhibition rate of WSAP3 reached 48.7% at a dose of 64mg kg^-1 after 15 days treatment. WSAP3 enhanced the aetivities of superoxide dismutase and catalase, which suggests that WSAP3 was effective in promoting the antioxidation ability and eliminating danger from free radicals. The result of flow cytometry showed that the WSAP3 had no activities of cell cycle inhibition or apoptosis-inducing activities. The anti-oxidation of WSAP3 was further confirmed by test in vitro, which might play an important role in anti-tumor activity. The immunological regulation of WSAP3, especially its effect on the phagocytosis ratio and phagocytosis index of rophage was also assayed in test in vivo.展开更多
Objective ： To investigate the mechanism of polymyxin B （ PMB ） antagonizing the biological activity of Hipopolysaccharide （LPS）. Methods： The affinity of PMB for LPS and lipid A was assayed by biosensor, and t...Objective ： To investigate the mechanism of polymyxin B （ PMB ） antagonizing the biological activity of Hipopolysaccharide （LPS）. Methods： The affinity of PMB for LPS and lipid A was assayed by biosensor, and the neutralization of PMB for LPS （2 ng/ml ） was detected by kinetic turbidimetric limnins test. The releases of TNF-α and IL-6 in murine peritoneal macrophages （PMφ） after exposure to LPS （ 100 ng/ml） were detected, and the expression levels of TLR4, TNF-α and IL-6 mRNA in PMφ induced by LPS （100 ng/ml） were measured by RT-PCR. Results： PMB had high-affinity to LPS and lipid A with dissociation equilibrium constants of 18.9 nmol/L and 11.1 nmol/L, respectively, and neutralized LPS in a dosedependent manner. Furthermore, PMB could markedly inhibit the expressions of TLR4, TNF-α and IL-6 mRNA and the release of cycokines in LPS-stimniated murine PMφ. Conclusions： PMB neutralizes LPS and inhibites the expression and release of cycokines in macrophages, in which the affinity of PMB for lipid A plays an important role.展开更多
文摘Depolymerization of agar was performed using agarase, which was extracted from the cell-free medium of a culture of marine bacterial Alterornonas sp. nov. SY 37-12. After ethanol fractionation and lyophilization, the water-soluble agar polysaccharide （WSAP3） was collected. The anti-tumor activity of the product was determined by using Sarcoma 180 tumor in mouse. The tumor inhibition rate of WSAP3 the product was determined by using Sarcoma 180 tumor in mouse. The tumor inhibition rate of WSAP3 reached 48.7% at a dose of 64mg kg^-1 after 15 days treatment. WSAP3 enhanced the aetivities of superoxide dismutase and catalase, which suggests that WSAP3 was effective in promoting the antioxidation ability and eliminating danger from free radicals. The result of flow cytometry showed that the WSAP3 had no activities of cell cycle inhibition or apoptosis-inducing activities. The anti-oxidation of WSAP3 was further confirmed by test in vitro, which might play an important role in anti-tumor activity. The immunological regulation of WSAP3, especially its effect on the phagocytosis ratio and phagocytosis index of rophage was also assayed in test in vivo.
基金This work was supported by the grant from the National Key Technologies R&D Program(G1999054203)
文摘Objective ： To investigate the mechanism of polymyxin B （ PMB ） antagonizing the biological activity of Hipopolysaccharide （LPS）. Methods： The affinity of PMB for LPS and lipid A was assayed by biosensor, and the neutralization of PMB for LPS （2 ng/ml ） was detected by kinetic turbidimetric limnins test. The releases of TNF-α and IL-6 in murine peritoneal macrophages （PMφ） after exposure to LPS （ 100 ng/ml） were detected, and the expression levels of TLR4, TNF-α and IL-6 mRNA in PMφ induced by LPS （100 ng/ml） were measured by RT-PCR. Results： PMB had high-affinity to LPS and lipid A with dissociation equilibrium constants of 18.9 nmol/L and 11.1 nmol/L, respectively, and neutralized LPS in a dosedependent manner. Furthermore, PMB could markedly inhibit the expressions of TLR4, TNF-α and IL-6 mRNA and the release of cycokines in LPS-stimniated murine PMφ. Conclusions： PMB neutralizes LPS and inhibites the expression and release of cycokines in macrophages, in which the affinity of PMB for lipid A plays an important role.
