镧对发菜细胞培养及氨基酸成分的影响

用Ｌａ（ＮＯ３）３处理液体培养的发菜细胞，研究镧对发菜细胞的生长及氨基酸成分的影响。结果表明，浓度为１－２００ｍｇ．Ｌ＾－１的Ｌａ（ＮＯ３）３均能促进发菜细胞的生长，以１００ｍｇ．Ｌ＾－１Ｌａ（Ｎｏ３）３作用最明显，     

铕对决明发根生长及有效成分生成的作用

以决明发根为材料,在培养基中附加０．００１～１０ｍｇ．Ｌ＾－１Ｅｕ＾３＋（ＥｕＣ１３）,测量发根的鲜重和干重,用高效液相色谱法测定游离蒽醌化合物含量。发有低剂量（０．００１,０．０１,１．０ｍｇ．Ｌ＾－１）Ｅｕ＾３＋抑制生长,０．００１ｍｇ．Ｌ＾－１Ｅｕ＾３＋抑制作用最强,干重比对照降低２２％;较低剂量（１０ｍｇ．Ｌ＾－１）Ｅｕ＾３＋处理的含量高于对照２６＾,高于Ｅｕ＾３＋１．０ｍｇ．Ｌ＾－１处理     

镧与钕对棕色固氮菌342菌株的海藻酸发酵的影响

报道了九种浓度镧或钕的发酵液对棕色固氮菌３４２菌株的海藻酸发酵的影响。结果表明，两种稀土浓度都为１００ｐｐｍ时，能刺激其细胞生长、发育和促进海藻的生成；抑制浓度分别大于２００和１５０ｐｐｍ。Ｌａ＾３＋在０～１００ｐｐｍ，而Ｎｄ＾３＋在０～１５０ｐｐｍ，其固氮量随浓度的提高而递增，ＣＭ／ＣＧ（甘露糖醛酸浓度／古洛糖醛酸浓度）比值则随浓度的提高而递减；Ｌａ＾３＋在１００～４００ｐｐｍ而Ｎｄ在１５０～４     

酸性镀铜体系的交流阻抗研究

研究了基础溶液（０．３ｍｏｌ／ＬＣｕＳＯ４＋１．９４ｍｏｌ／ＬＨ２ＳＯ４）以及添加６０ｍｇ／ＬＣｌ＾－，３００ｍｇ／ＬＯＰ－２１，３０ｍｇ／ＬＰＥＧ－６０００，１０ｍｇ／Ｌ２－噻唑啉基－二硫丙烷酸钠（代号ＴＤＹ，自合成添加剂）后体系的阻抗行为，结果表明：１）Ｃｌ＾－在铜沉积中有增大阴极极化的作用；２）铜离子的放电为分步反应；即Ｃｕ＾２＋→Ｃｕ＾＋；Ｃｕ＾＋→Ｃｕ（吸附）→Ｃｕ（晶格），在含有Ｃｌ＾     

镧和钙对人红细胞膜的作用

采用荧光偏振，自旋标记电子顺磁共振波谱和激光拉曼光谱等技术研究了镧和钙对人红细胞膜结构和功能的影响。结果表明，低浓度的Ｌａ＾３＋（０．５ｕｍｏｌ／Ｌ）对（Ｎａ＾＋＋Ｋ＾＋）－ＡＴＰ酶，Ｍｇ＾２＋－ＡＴＰ酶有轻微的激活作用，随着浓度的增大，则明显抑制酶的活性。Ｌａ＾２＋可降低红细胞 的膜脂充动性，使膜蛋白酰胺１’－ａ螺旋振动强度减弱；Ｃａ＾２＋对膜脂流动性和膜蛋白酰胺１’－ａ螺旋的影响比Ｌａ＾３＋小     

稀土元素荧光增强效应的研究──RE对Eu－2－（2－二苯乙酰基）－1，3－茚二酮－十六烷基三甲基溴化铵体系的荧光增强

研究了稀土元素Ｌａ~（３＋）、Ｇｄ~（３＋）、Ｙｂ~（３＋）、Ｌｕ~（３＋）、Ｙ~（３＋）及Ｓｃ~（３＋）对Ｅｕ－２－（２－二苯乙酰基）－１，３－茚二酮－阳离子表面活性剂体系的荧光增强效应，结果表明，在上述增强离子存在下，体系的荧光强度分别增加１０、１３０、３０、５０、５２和２０倍，利用标准加入法测定了混合稀土氧化物中的铕，铕浓度在１．０×１０~（－１０）～６．０×１０~（－７）ｍｏｌ／Ｌ范围内与荧光强度呈线性关系，最低检出限为６．０×１０~（－１２）ｍｏｌ／Ｌ。     

褪色光度法测定SO_3~(2-)的研究

本文研究了ＳＯ２－３褪色碱蓝６Ｂ的反应，在ｐＨ５．２ＨＡｃ－ＮａＡｃ缓冲介质中，ＳＯ２－３浓度在０．３９～１２ｍｇ／Ｌ范围内符合比尔定律，仅Ｆｅ３＋、Ｎｉ２＋、Ｃｒ３＋干扰测定，用于食品中ＳＯ２－３的测定，结果令人满意。     

L－半胱氨酸的停流流动注射动力学快速测定法

利用Ｌ－半胱氨酸可还原Ｆｅ（３＋），使之生成Ｆｅ（２＋）－邻菲　啉有色络合物的反应，建立了Ｌ－半胱氨酸的停流流动注射动力学分光光度测定的新方法。该法简便、灵敏、快速、准确、选择性高，检测限为１６ｍｇ／Ｌ，分析频率达３０样／ｈ。取Ｌ－半胱氨酸浓度为１６０ｍｇ／Ｌ时，测量的相对标准偏差为０．５５％（ｎ＝６）。实际样品加标回收率达９８．７％。     

甲烷与二氧化碳重整制取合成气反应的研究 (I)Sr_(1-x)La_xNiAl_(11)O_(19)催化剂的物理化学性质表征

合成了具有磁铅石结构的Ｓｒ１－ｘＬａｘＮｉＡｌ１１Ｏ１９系列催化剂，并用ＸＲＤ、ＵＶ－ＤＲＳ、Ｈ２－Ｏ２滴定及Ｐｙ－ＩＲ等方法对其体相及表面性质进行了表征．结果表明，Ｌａ３＋离子能够同晶取代Ｓｒ２＋离子进入催化剂晶格内部；随着Ｌａ３＋含量增加，催化剂的结晶度提高，从而降低了镍的还原性，并使金属镍在表面上的分散度略有提高；在ＳｒＮｉＡｌ１１Ｏ１９中掺入Ｌａ３＋离子，能够抑制晶体沿ｃ轴方向的生长，提高其比表面积；同时Ｌａ３＋离子对Ｓｒ２＋离子的调变，减少了表面的酸中心数目     

阿斯美胶囊中四种组分的高效液相色谱分析

建立了反相高效液相色谱法测定阿斯美胶囊中氨茶碱、盐酸甲氧非那明、马来酸氯苯那敏及那可汀四种组分的含量。色谱柱为ＳｐｈｅｒｉｓｏｒｂＣ８，５μｍ，２００ｃｍ×４０ｍｍＩＤ，流动相为体积分数０５％的三乙胺溶液（磷酸调节ｐＨ５５）＋乙腈＋甲醇（５５０＋３６８＋８２），检测波长为２６４ｎｍ，线性范围分别为：氨茶碱３１２５～２５０ｍｇ／Ｌ，γ＝０９９９６，盐酸甲氧非那明１５６２５～１２５０ｍｇ／Ｌ，γ＝１００００，马来酸氯苯那敏２５～２００ｍｇ／Ｌ，γ＝０９９９９，那可汀８７５～７００ｍｇ／Ｌ，γ＝０９９９９；回收率（ｎ＝３）分别为１０１２％，１００８％，９９９％，９９５％；精密度：日内平均ＲＳＤ（ｎ＝６）分别为０７％，０４％，０４％，０６％；日间平均ＲＳＤ（ｎ＝３）分别为１０％，１０％，１１％，１２％。     

La对Pb， Cd复合污染大豆幼苗的缓解作用

以盆栽法研究了Ｐｂ，Ｃｄ复合污染对大豆幼苗的影响及Ｌａ对Ｐｂ，Ｃｄ复合胁迫的缓解效应。结果显示，Ｐｂ５００ｍｇ／Ｌ和Ｃｄ１００ｍｇ／Ｌ的混合液严重抑制大豆幼苗代谢与生长。叶面喷施３０ｍｇ／ＬＬａＣｌ３一次，能减轻Ｐｂ，Ｃｄ复合污染造成的伤害。这与Ｌａ能增加大豆幼苗光合速率，提高叶绿素含量与硝酸还原酶活性，降低质膜透性与植株中Ｐｂ，Ｃｄ含量，维持ＴＴＣ还原力等多重作用相关。     

La降低Pb,Cd在大豆植株内富集量的研究

植物具有富集重金属的特性，重金属在生态系统食物链中迁移、浓缩，对人类健康造成危害．因此，降低植物体内重金属含量，确保食用的安全性成为有待解决的问题．目前主要减灾手段有客土深翻的工程学方法；植物净化的生物学方法及提高植物自身抗性的生态学方法［１］．本文...     

稀土元素镧对中国樱桃试管苗生长的影响

研究了La对中国樱桃试管苗再生与生长的作用。结果表明，适宜浓度的La（10－40mg/L）能够促进樱桃试管苗的生长与分化，有利于对培养基中微量元素的吸收。但高浓度La抑制樱桃幼苗的生长。     

Enhanced cellulase production byAspergillus fumigatus fresenius

The compost isolate,Aspergillus fumigatus, produces the exoglucanase, endoglucanase, and Β-glucosidase enzymes required for the breakdown of crystalline cellulose. Cellulose breakdown and extracellular enzyme levels in liquid culture can be affected by low pH values attained during fungal growth. During growth ofA. fumigatus on modified Czapeck-Dox medium containing 1% (w/v) Avicel, it was found that Β-glucosidase activity was lost and endoglucanase activity, reduced, when pH values fell below 3. The effect of buffering (0.2M phosphate, pH 6.15) was examined and compared with the unbuffered medium. Beta-glucosidase activity could be detected throughout the incubation period in the buffered medium and endoglucanase activity was approximately tenfold greater. Exoglucanase activity also showed an increase in the buffered system. Concentrations of phosphate buffer ranging from 0.05 to 0.8M were incorporated into the medium and optimum cellulose breakdown and extracellular enzyme production occurred between 0.1 and 0.2M. Reports suggest that increasing substrate concentration does not improve upon the levels of extracellular cellulase produced because of enzyme inactivation resulting from rapid decreases in pH. Using the buffered medium described previously,A. fumigatus was grown on concentrations of Avicel ranging from 0.5 to 10% (w/v). Cellulose breakdown and extracellular enzyme production was compared with that achieved by a similar nonbuffered system. Endoglucanase and Β-glucosidase activity increased with time and with substrate concentration up to 5% (w/v) in the buffered medium. Beta-glucosidase was negligible at all concentrations of Avicel in the unbuffered medium and endoglucanase activity decreased with increasing substrate concentration with maximum levels approximately eightfold lower than in the buffered system. Extracellular exoglucanase activity was lower in the buffered medium and only increased to levels comparable with those achieved by the unbuffered medium towards the end of the incubation period. In the unbuffered system, exoglucanase activity decreased with increasing substrate concentration, but no such effect was observed in the buffered medium. Negligible growth occurred in both media at 10% (w/v) substrate. The percentage weight loss recorded in the Czapeck-Dox medium also decreased with increasing substrate concentration, while in the buffered medium, over 95% weight loss was recorded in up to 5% (w/v) Avicel. It appeared that cellulose breakdown was more rapid in the buffered medium and a time-course carried out to determine the rate of cellulolysis showed 97% cellulose breakdown after 12 d, corresponding to a plateau and a subsequent decrease in extracellular cellulase levels.     

Purification and partial characterization of a lipase from Bacillus coagulans ZJU318

An extracellular lipase was purified from the fermentation broth of Bacillus coagulans ZJU318 by CM-Sepharose chromatography, followed by Sephacryl S-200 chromatography. The lipase was purified 14.7-fold with 18% recovery and a specific activity of 141.1 U/mg. The molecular weight of the homogeneous enzyme was (32 kDa), determined by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis. The enzyme activity was maximum at pH 9.0 and was stable over a pH range of 7.0–10.0, and the optimum temperature for the enzyme reaction was 45°C. Little activity loss (6.2%) was observed after 1 h of incubation at 40°C. However, the stability of the lipase decreased sharply at 50 and 60°C. The enzyme activity was strongly inhibited by Ag⁺ and Cu²⁺, whereas EDTA caused no inhibition. SDS, Brij 30, and Tween-80 inhibited lipase, whereas Triton X-100 did not significantly inhibit lipase activity.     

镧对青菜生物量、植株氮磷钾含量及土壤酶活性的影响

利用盆栽试验,研究了镧对青菜生物量、植株氮磷钾含量及土壤酶活性的影响.结果表明,施用镧显著增加了青菜生物量,与对照相比地上部干重提高了5.49%～19.78%,根干重提高了13.51%～51.35%.在低浓度下,随镧浓度的升高,青菜茎叶和根的氮、磷、钾含量逐渐增加,到一定浓度后,随着镧浓度的继续升高,含量反而逐渐降低.镧施入土壤后对脲酶、酸性磷酸酶、转化酶活性表现出刺激作用并随浓度的升高而增强,而对过氧化氢酶活性有轻微的抑制作用,对脱氢酶活性有强烈的抑制作用.     

Cellulase production and regulation byAgaricus bisporus

Cellulose is degraded during the growth of the cultivated mushroomA. bisporus on composted straw. At the time of sporophore enlargement, a marked increase in extracellular endocellulase activity occurs. A high level of enzyme activity is maintained during subsequent cropping cycles. Some of the factors affecting growth and production of extracellular endocellulase activity byA. bisporus cultured in simple defined liquid media have been examined. Endocellulase production by the fungus closely paralleled mycelial growth in cultures containing microcrystalline cellulose. The enzyme was induced by various celluloses and cellobiose. In the presence of a cellulose inducer, glucose and cellobiose repressed enzyme production. Endocellulase activity in culture filtrates was inversely related to cellulose concentration in the culture. Although the activity of free enzyme was low, in high concentrations of cellulose more cellulose was degraded. Evidence was obtained for the existence of two forms of endocellulase activity. One form adsorbed strongly to cellulose and was predominant in cultures low in cellulose. In cultures with a high cellulose content, a nonadsorbable form of the enzyme was more abundant. It is suggested that the pattern of cellulase activities produced whenA. bisporus is grown on different concentrations of cellulose is partly accounted for by its adsorption to the cellulose.     

Sesbania drummondii cell cultures: ICP-MS determination of the accumulation of Pb and Cu

Sesbania cell cultures grown in the presence of different concentrations of Pb (0-1000 mg/L) and Cu (0-500 mg/L) were assayed for growth, metal accumulations and activities of antioxidative enzymes: superoxide dismutase (SOD), catalase (CAT) and guaiacol peroxidase (GPX). These cultures tolerated Pb up to a concentration of 500 mg/L, registering a fresh weight growth of 500% in 3 weeks. At the same time, cultures registered a growth of 200% in 3 weeks at a Cu concentration of 100 mg/L showing less tolerance than Pb. However, Sesbania cells accumulated more Cu than Pb, as determined by ICP-MS, at all the treatments tested. Cu accumulation reached 3000 mg/kg (dry weight) at a Cu treatment of 100 mg/L, while Pb accumulation was only over 150 mg/kg (dry weight) at 500 mg Pb/L. Metal accumulations were positively correlated with induction of SOD and CAT activities in both the metal treatments. SOD activity of callus was 105 U/mg (fresh weight) at a Pb treatment of 500 mg/L and the corresponding Pb accumulation of 160 mg/kg (dry weight), while the activity rose to 300 U/mg (fresh weight) at a Cu treatment of 100 mg/L and the corresponding Cu accumulation of 3000 mg/kg (dry weight). The pattern of GPX activities was, however, different, particularly in Pb treatments where activities declined with increasing concentrations of Pb in the cells as well as growth medium. This study shows how Sesbania cells withstand heavy metal stress by induction of antioxidative enzyme activities.     

来源于类芽孢杆菌属碱性甲壳素酶的分离纯化及其性质

甲壳素,又名几丁质(chitin),是自然界中含量仅次于纤维素的第二大天然多糖,有第六生命要素之美称.其主要存在于甲壳类动物的外壳、真菌细胞的细胞壁以及一些昆虫的外壳中,每年自然界中约有100多亿吨甲壳素生成.甲壳素是由2-乙酰氨基-2-脱氧-D-吡喃葡萄糖和2-氨基-2-脱氧-D-吡喃葡萄糖通过β-1,4糖苷键连接而成的二元线性聚合物,分子链中分布许多羟基、氨基及乙酰氨基,形成大量分子间及分子内氢键,致使其结晶度较高,化学性质十分稳定,直接利用较为困难.甲壳素不溶于稀酸、稀碱以及一般有机溶剂,工业上常用强酸强碱法处理甲壳素,以制备壳寡糖类产品,但该方法具有产品结构不单一,环境污染较为严重等缺点.甲壳素酶可特异性水解甲壳素链中β-1,4糖苷键,得到甲壳寡糖和N-乙酰氨基葡萄糖.酶解法降解甲壳素工艺简单、反应条件温和、环境友好,有很好的应用前景.我们以Paenibacillus pasadenensis CS0611为出发菌株,以蟹壳粉末为培养基唯一碳源及氮源,在适宜条件下培养48 h.发酵液经离心、硫酸铵(80％饱和度)盐析、透析除盐后得到粗酶液.再利用HiTrap DEAE FF离子交换层析和HiLoad 26/600Superdex 200 pg凝胶过滤层析对该粗酶液进行分离纯化,以得到电泳纯甲壳素酶.所制备甲壳素酶比活力为10.28 U/mg,最终纯化倍数为5.3,酶活得率为15.7％.SDS-PAGE结果表明,该甲壳素酶相对分子质量约为69 kDa.后经MALDI-TOF-MS鉴定,该酶部分肽段和来源于另一株Paenibacillus pasadenenss的甲壳素酶(accession No:gi655151624)具有较高的同源性,进一步证实所纯化蛋白为甲壳素酶.对上述纯化的甲壳素酶的酶学性质进行研究,结果发现:其最适反应温度为50℃,在20-35℃内有较好的稳定性,50℃及以上热稳定性较差;最适pH为5.0,在pH4.0-11.0间具有较高稳定性,表明该酶具有很好的耐碱性;金属离子对该酶催化活性没有明显的激活作用,表明该甲壳素酶是非金属酶.同时,对该酶的底物特异性进行研究,发现该酶对胶体甲壳素和甲壳素水解能力较强,对淀粉和纤维素无水解能力,对不同脱乙酰度的壳聚糖的水解程度随脱乙酰度不同而变化,表明该酶只能特异性识别并降解GlcNAc-GlcNAc之间的糖苷键;以胶体甲壳素为底物时,米氏常数Km为4.41 mg/mL,最大反应初速度为1.08 mg/min.利用薄板层析和高效液相色谱对酶解产物进行分析,结果表明该甲壳素酶对胶体甲壳素的降解产物主要是(GlcNAc)2.综上所述,本研究所涉甲壳素酶在甲壳二糖的酶法制备方面具有较好的应用前景.     

Biotransformation of Indole to Indigo by the Whole Cells of Phenol Hydroxylase Engineered Strain in Biphasic Systems

Biotransformation of indole to indigo in liquid–liquid biphasic systems was performed in Escherichia coli cells expressing phenol hydroxylase. It was suggested that indole could inhibit the cell growth even at low concentration of 0.1 g/L. The critical Log P for strain PH__IND was about 5.0. Three different solvents, i.e., decane, dodecane, and dioctyl phthalate, were selected as organic phase in biphasic media. The results showed that dodecane gave the highest yield of indigo (176.4 mg/L), which was more than that of single phase (90.5 mg/L). The optimal conditions for biotransformation evaluated by response surface methodology were as follows: 540.26 mg/L of indole concentration, 42.27 % of organic phase ratio, and 200 r/min of stirrer speed; under these conditions, the maximal production of indigo was 243.51 mg/L. This study proved that the potential application of strain PH__IND in the biotransformation of indole to indigo using liquid–liquid biphasic systems.