In this study, a xylanase-produeing Aspergillus niger strain, NS-1, was screened and isolated from agricultural and forestry wastes. Based on single-fac- tor experiments, the effects of different carbon sources, compo...In this study, a xylanase-produeing Aspergillus niger strain, NS-1, was screened and isolated from agricultural and forestry wastes. Based on single-fac- tor experiments, the effects of different carbon sources, composite carbon sources, nitrogen sources, calcium carbonate concentrations, initial pH and surfactants on xylanase production by A. niger NS-1 were investigated. The results indicated that the most appropriate carbon source was corncobs ; the best composite carbon source was corncobs ＋ xylan, which was conducive to xylanase secretion; the most suitable nitrogen source was ammonium sulfate. Xylanase activity reached the highest in the medium added with 1.5% calcium carbonate and SDS as a surfactant with an initial pH of 5.0. This study provided the basis for the production of high-activity xylanase.展开更多
AIM: To investigate experimentally the effects of methionineenkephalin on signal transduction of mouse myeloma NS-1cells.METHODS: The antigen determinate of delta opioidreceptor was designed in this lab and the polype...AIM: To investigate experimentally the effects of methionineenkephalin on signal transduction of mouse myeloma NS-1cells.METHODS: The antigen determinate of delta opioidreceptor was designed in this lab and the polypeptidefragment of antigen determinate with 12 amino acidsresidues was synthesized. Monoclonal antibody against thispeptide fragment was prepared. Proliferation of Mouse NS-L cells treated with methionine enkephalin of 1x10-6 mol.L-1was observed. The activities of protein kinase A (PKA) andprotein kinase C (PKC) were measured and thereby themechanism of effect of methionine enkephalin was postulated.RESULTS: The results demonstrated that methionineenkephalin could enhance the proliferation of NS-1 cells andthe effect of methionine enkephalin could be particularlyblocked by monoclonal antibody. The activity of PKA wasincreased in both cytosol and cell membrane. With referenceto PKC, the intracellular activity of PKC in NS-1 cells waselevated at 1x10-7 mol.L-1 and then declined gradually asthe concentration of methionine enkephalin was raised. Theeffects of methionine enkephalin might be reversed by bothnaloxone and monoclonal antibody.CONCLUSION: Coupled with the findings, it in-dicates thatthe signal transduction systems via PKA and PKC are involvedin the effects of methionine enkephalin by binding with thetraditional opioid receptors, and therefore resulting in differentbiological effects.展开更多
基金Supported by Project of Taizhou Science and Technology Bureau(TS019)
文摘In this study, a xylanase-produeing Aspergillus niger strain, NS-1, was screened and isolated from agricultural and forestry wastes. Based on single-fac- tor experiments, the effects of different carbon sources, composite carbon sources, nitrogen sources, calcium carbonate concentrations, initial pH and surfactants on xylanase production by A. niger NS-1 were investigated. The results indicated that the most appropriate carbon source was corncobs ; the best composite carbon source was corncobs ＋ xylan, which was conducive to xylanase secretion; the most suitable nitrogen source was ammonium sulfate. Xylanase activity reached the highest in the medium added with 1.5% calcium carbonate and SDS as a surfactant with an initial pH of 5.0. This study provided the basis for the production of high-activity xylanase.
基金National Science Foundation of China,No.30060091
文摘AIM: To investigate experimentally the effects of methionineenkephalin on signal transduction of mouse myeloma NS-1cells.METHODS: The antigen determinate of delta opioidreceptor was designed in this lab and the polypeptidefragment of antigen determinate with 12 amino acidsresidues was synthesized. Monoclonal antibody against thispeptide fragment was prepared. Proliferation of Mouse NS-L cells treated with methionine enkephalin of 1x10-6 mol.L-1was observed. The activities of protein kinase A (PKA) andprotein kinase C (PKC) were measured and thereby themechanism of effect of methionine enkephalin was postulated.RESULTS: The results demonstrated that methionineenkephalin could enhance the proliferation of NS-1 cells andthe effect of methionine enkephalin could be particularlyblocked by monoclonal antibody. The activity of PKA wasincreased in both cytosol and cell membrane. With referenceto PKC, the intracellular activity of PKC in NS-1 cells waselevated at 1x10-7 mol.L-1 and then declined gradually asthe concentration of methionine enkephalin was raised. Theeffects of methionine enkephalin might be reversed by bothnaloxone and monoclonal antibody.CONCLUSION: Coupled with the findings, it in-dicates thatthe signal transduction systems via PKA and PKC are involvedin the effects of methionine enkephalin by binding with thetraditional opioid receptors, and therefore resulting in differentbiological effects.
