排序方式: 共有18条查询结果,搜索用时 250 毫秒
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采用气相色谱 质谱联用方法分析了福建建瓯产竹沥成分,共分离鉴定有机物46种,其中主要成分18种,占出峰总面积的98%.研究了竹沥对不同类型腐败菌的抑制效果,结果显示,竹沥对细菌和真菌均具较强的抑制作用,其中金黄色葡萄球菌和枯草芽孢杆菌的抑菌圈直径为26mm,大肠杆菌为24mm,黑曲霉为23mm.表明竹沥是一种良好的天然抑菌剂. 相似文献
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通过氮离子束诱变节杆菌(Arthrobacter sp.g-1984)筛选到黄嘌呤氧化酶高产菌株X7,产酶活力为24.49 U/g,是出发株产酶活力(8.81 U/g)的2.78倍,经发酵条件优化后,产酶活力达到36.67 U/g,是出发菌株产酶活力的4.16倍,产酶高峰缩短了21 h.对细菌黄嘌呤氧化酶酶学性质进行了初步研究,其最适反应条件为37℃、pH 6.5、Fe2 对酶活力有较强的抑制作用,EDTA对酶活力有明显的激活作用. 相似文献
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竹沥组分分析及抑菌作用 总被引:3,自引:0,他引:3
采用气相色谱-质谱联用方法分析了福建建瓯产竹沥成分,共分离鉴定有机物46种,其中主要成分18种,占出峰总面积的98%,研究了竹沥对不同类型腐败菌的抑制效果,结果显示,竹沥对细菌和真菌均具较强的抑制作用,其中金黄色葡萄球菌和枯草芽孢杆菌的抑菌圈直径为26mm,大肠杆菌为24mm,黑曲霉为23mm,表明竹沥是一种良好的天然抑菌剂。 相似文献
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奶油黄嘌呤氧化酶的酶学性质研究 总被引:1,自引:0,他引:1
利用反向高效液相色谱(RP-HPLC)测定该酶产物尿酸的生成量,研究黄嘌呤氧化酶的酶学特性。结果表明,在50mmol/L Tris—HCI缓冲液和O.24mmol/L黄嘌呤的体系中,该酶检测反应的最适温度为37℃,最适pH8.4。XOD在pH7.O~9.0,40℃以下稳定,对黄嘌呤的Km值为0.043mmol/L。XOD酶激活剂包括水杨酸钠、半胱氨酸、组胺、硫酸铵、乙二胺四乙酸等。金属离子对其活性有抑制作用。低浓度表面活性剂Tween80、SDS和TritonX.100对该酶活力影响不明显。关键词:黄嘌呤氧化酶;酶学特性;稳定性 相似文献
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In this paper,a model is presented to correlate and predict the swelling behavior of hydrogels in aqueous solutions of electrolytes.The model is a combination of VERS-model,"phantom network" theory and "free-volume"contribution.The VERS-model is used to calculate Gibbs excess energy; "phantom network" theory to describe the elastic properties of polymer network,and "free-volume" contribution to account for additional difference in the size of the species.To test the model,a series of N-isopropylacrylamide based hydrogels are synthesized by free radical polymerization in oxygen-free,deionized water at 25°C under nitrogen atmosphere.Then,the degree of swelling of all investigated gels as well as the partition of the solute between the gel phase and the surrounding coexisting liquid phase are measured in aqueous solution of sodium chloride.The model test demonstrates that the swelling behavior correlated and predicted by the model agrees with the experimental data within the experimental uncertainty.The phase transition appeared in the experiment,and the influences of the total mass fraction of polymerizable materials ξgel as well as the mole fraction of the crosslinking agent yCR on the swelling behavior of IPAAm-gels can also be predicted correctly.All these show the potential of such model for correlation and prediction of the swelling behavior of hydrogels in aqueous solutions of electrolytes. 相似文献