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1.
对16种新鲜食用菌SOD活性、热稳定性及同工酶类型进行研究,结果表明,大多数食用菌有较高SOD活性,其中以金顶侧耳的酶活性最高,达1622U/g,比活性也有366U/mg,酶活性超过1000U/g的有糙皮侧耳、蘑菇、草菇和柳松菇,有14种食用菌SOD活性超过500U/g.食用菌中主要含对氯仿乙醇液敏感的SOD,占其总活性的70%~96%,以金顶侧耳和糙皮侧耳的活性最高,分别为1538U/g和1052U/g.SOD的热稳定性研究表明,大多数食用菌SOD在90℃加热10min后,能保留40%以上的活性,金针菇、滑菇、毛头鬼伞和大球盖菇的菌盖在90℃加热10min后,能保留75%以上的活性.食用菌SOD类型为Mn-SOD,未发现有Cu·Zn-SOD.菌盖和菌柄的分析结果表明,二者在SOD活性、热稳定性及同工酶谱带数方面存在一定的差异.  相似文献   

2.
以安琪活性干酵母为出发菌种,分析了培养基初始硒浓度、接种量、装液量、温度、初始pH以及转速等发酵条件对酵母生物量及富硒量的影响,并通过正交试验设计初步确定了培养的最优方案.在最佳的摇瓶培养条件下(初始硒浓度25μg/mL,接种量10%,装液量60/250 mL,温度30℃,初始pH 5.0,摇床转速160 r/min,培养40 h后),该活性干酵母的生物量及富硒量分别达到9.89 g/L、954 μg/g.  相似文献   

3.
为了探讨大球盖菇黄酮类化合物提取工艺及其抑菌效果,通过正交试验确定了大球盖菇黄酮类化合物的优化提取工艺条件;采用大球盖菇黄酮类化合物对大肠杆菌、青霉菌、啤酒酵母进行抑菌试验.结果表明,优化后的提取工艺为:乙醇体积分数95%,物料比为1∶90,温度60℃,时间120 min,提取率为7.94‰.40 g/L的大球盖菇黄酮类化合物溶液对大肠杆菌和青霉菌有抑制作用;20 g/L和10 g/L的溶液只对大肠杆菌有抑制作用,对青霉菌没有抑制作用;大球盖菇黄酮类化合物对啤酒酵母没有抑制作用;对大肠杆菌的抑制作用要强于对青霉菌的抑制作用.  相似文献   

4.
天然富硒绿茶醇溶性活性物质提取条件优化   总被引:1,自引:0,他引:1  
以天然富硒绿茶为原料,采用超声波辅助提取醇溶性活性物质,通过单因素实验和正交试验优化了提取条件.结果表明最佳提取条件为:乙醇体积分数50%,料液比1∶25,提取温度60℃,时间2h,超声波功率400W,提取得率为44.44%.制得的富硒绿茶活性物质化学组成为:硒1.03μg/g,茶蛋白31.09%,茶多酚53.22%,茶多糖13.56%.  相似文献   

5.
富硒鲍鱼菇的深层培养及其特性   总被引:9,自引:0,他引:9  
报导在含有不同浓度无机硒的液体培养基中培养鲍鱼菇菌丝体,探讨其耐硒和富硒特性。结果表明:鲍鱼菇有较强的耐硒特性和很强的富硒能力,鲍鱼菇菌丝体硒含量随培养基质硒浓度的增加而增高,在培养基中添加硒量为5μg/ml时,富硒鲍鱼菇菌丝体含硒量可达200μg/ml时,为对照的40倍,硒回收率达38.8%,其氨基酸及多糖含量均高于对照。  相似文献   

6.
苦参碱和氧化苦参碱的抑菌活性及增效作用   总被引:13,自引:0,他引:13  
研究了苦参碱、氧化苦参碱对几种林木病原真菌孢子萌发和菌丝生长的抑制活性.结果表明苦参碱和氧化苦参碱对供试林木病原真菌孢子萌发均有抑制作用,其中苦参碱对杨褐斑病菌和龙竹材霉变菌抑制作用较强,致死中量EC50分别为123、272 μg/mL.氧化苦参碱对杉木猝倒病菌抑制作用最强,EC50为26μg/mL,活性比供试的75%百菌清可湿性粉剂(EC50=91μg/mL)和70%甲基托布津可湿性粉剂(EC50=283 μg/mL)的活性高.苦参碱和氧化苦参碱对供试林木病原真菌菌丝生长有抑制作用,其中苦参碱对松枯梢病菌抑制作用较强,EC50为428μg/mL;氧化苦参碱对华山松腐烂病菌的抑制作用较强,EC50为323μg/mL.以苦参碱(氧化苦参碱)与合成农药按1:5质量比混合进行林木病原真菌菌丝生长抑制增效试验,结果表明混剂的EC50均低于34 μg/mL,共毒系数明显大于100,对华山松腐烂病菌具显著增效作用,对杉木猝倒病菌具不同程度的相加或增效作用.  相似文献   

7.
研究基于高效液相色谱-氢化物发生原子荧光光谱建立了一种适用于富硒蛋白粉、富硒大米、富硒香菇和富硒酵母等富硒食品中硒酸根、硒代胱氨酸、甲基硒代半胱氨酸、硒代蛋氨酸的检测方法。样品经Tris缓冲液提取,蛋白酶和胰蛋白酶酶解,以V(20mmol/L磷酸氢二胺水溶液,pH=6.0)∶V(甲醇)=98∶2为流动相,经Hamilton PRP-X100阴离子交换色谱柱分离测定。结果表明,4种硒形态化合物在5~100μg/kg范围内线性良好(R2>0.999),方法检出限可达25~50μg/kg,平均加标回收率为81.37%~93.80%,且RSD为2.80%~7.22%。应用此方法对4种市售富硒食品(富硒蛋白粉、富硒大米、富硒香菇和富硒酵母)中4种硒形态化合物进行检测,前处理步骤简单,测定快速、准确度和灵敏度高,为食品中硒形态评价和质量控制提供了方法和依据。  相似文献   

8.
为获得富硒黑木耳菌丝体,以亚硒酸钠为硒源对黑木耳(Auricularia auricular)高产菌株G6进行富硒发酵条件优化.以菌丝体性状和菌丝体硒含量为指标考查不同硒质量浓度对其生长的影响,并确定最适硒质量浓度;通过单因素和正交实验对G6菌株液体富硒发酵条件进行优化.结果,培养基中硒质量浓度<50 mg/L时,菌丝体的硒含量随硒质量浓度的提高而提高;硒质量浓度为50 mg/L时,菌丝体硒含量最高,为8.5 μg/g;硒质量浓度>50mg/L时,硒含量不升反降.表明适量亚硒酸钠有利于菌丝体对硒的吸收和利用,过量添加时则抑制菌丝体生长,不利于菌丝体对硒的吸收和利用.优化后的富硒黑木耳G6菌株液体发酵培养条件为硒质量浓度50mg/L,玉米粉15 mg/L,豆饼粉20 mg/L,装液量200 mL/500 mL三角瓶,转速160 r/min,25℃发酵培养6d.发酵液中菌丝体硒质量分数达到9.2 μg/g,发酵液多糖质量浓度可达3.7 g/L.  相似文献   

9.
纳豆芽孢杆菌可以转化亚硒酸钠为有机硒。对一株纳豆芽孢杆菌的生长曲线进行测定,确定了亚硒酸钠适宜的添加时间和添加量。以纳豆芽孢杆菌BSN424为出发菌株,采用常压室温等离子体诱变系统进行诱变,根据耐硒和富硒能力筛选,经连续传代培养后筛选出了富硒纳豆芽孢杆菌。结果表明,适宜加硒时间为培养后3h,培养时间为24h,培养基适宜硒质量浓度为6μg/mL,常压室温等离子体诱变系统功率为100W,诱变时间为25s。诱变后筛选得到一株具有较高富硒能力的诱变菌株BN-44,经摇瓶发酵后的富硒量为1136.43μg/g,相比出发菌株的742.12μg/g提高了53.13%。研究表明常压室温等离子体诱变育种能有效地对纳豆芽孢杆菌BSN424进行诱变,旨在为有机硒生物转化法中寻找益生菌富硒载体及其诱变育种提供一定依据。  相似文献   

10.
对富硒沼泽红假单胞菌菌体中微量元素硒含量的测定方法进行了研究,采用微波消解-紫外分光光度法测定了样品中的硒含量,对微波消解样品和紫外分光光度法的各种操作条件进行了优化,得到的优化条件是:消解液为HNO3/H2O2 5:1(V/V),微波功率为650 W,消解时间为3 min,测定波长为334 nm,配位剂用量为3 mL,配合反应酸度及萃取酸度为2.0,反应温度为45℃,反应时间为50 min.在优化条件下,该方法的测定范围为1~200μg(y=0.0104x+0.0024,r=0.9997),检出限达0.91μg,相对标准偏差为1.76%,回收率为98.4~103.1%.该方法具有灵敏度高、稳定性好、操作简单等显著优点,适于基层实验室和工业生产中应用.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

19.
20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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