植物胞外CaM调节机理初探

利用ＮＡＤ激酶法和平衡透析法,作者研究了不同ｐＨ条件对Ｃａ＾２＋,钙调素（ＣａＭ）的结合能力及ＣａＭ激活ＮＡＤ激酶的影响。结果发现：Ｈ＾＋不仅能降低Ｃａ＾２＋与ＣａＭ的结合能力而且还能显著抑制ＣａＭ对ＮＡＤ激酶的激活。本实验证实了酸性条件下不利于ＣａＭ的活性状态的转变,即ｐＨ值低时激活ＣａＭ需要更多的Ｃａ＾２＋。此研究结果为植物胞外ＣａＭ的活性状态的转变,即ｐＨ值低时激活ＣａＭ需要更多的Ｃａ＾２＋     

胞外分泌物对铜绿微囊藻混凝去除的影响

以铜绿微囊藻为对象,研究了胞外分泌物(EOM)对不同类型混凝剂混凝除藻的影响,并初步探究了其影响机理.结果表明,不同类型的混凝剂具有不同混凝特性和混凝除藻效果.EOM对混凝的影响具有利弊双重性,即在混凝初期由于优先结合混凝剂,减小了有效投加量并阻碍电中和,具有一定的负面效应;而在混凝后期,初期与混凝剂结合的EOM具有增强架桥和网捕卷扫作用,起到了提高絮体密实性和改善沉降性能等有利作用.综合而言,当EOM质量浓度处于3～5mg.L-1时,混凝剂的除藻效果最好.因此,合理利用EOM是提高混凝除藻效果、减少药剂投加量的重要因素.研究结果为不同环境条件下除藻剂及其工艺条件的选择提供了重要的参考依据.     

人共刺激分子B7-1/CD80胞外编码区cDNA的克隆及序列分析

用RT－PCR法从人外周血单核细胞克隆了编码共刺激分子B7－1／CD80胞外区的cDNA，并用Snager链终止法进行测序，结果表明，所cDNA片段的序列与GenBank中已报道的人B7－1／CD80 cDNA序列的对应部分仅有两个碱基存在差异（658位A→T，773位A→G），这为探讨B7－1／CD80分子的生物学功能奠定了基础。     

膜生物反应器中的非丝状菌污泥膨胀

研究了膜生物反应器中非丝状菌膨胀的原因以及此类膨胀对污泥混合液过滤性能的影响和通过污泥黏度、胞外聚合物和污泥颗粒粒径三方面对膜生物反应器中的污泥混合液进行了分析；运用死端过滤实验方法，研究了非丝状菌膨胀时污泥混合液过滤性能的影响，实验结果表明，污泥沉降性能与污泥黏度有较好的相关性，活性污泥中的胞外聚合物是引起非丝状菌膨胀的关键因素；膜生物反应器中污泥非丝状菌膨胀主要因反应器中累积的高浓度胞外聚合物所致；非丝状菌污泥膨胀极大影响了污泥混合液的过滤性能，污泥膨胀后过滤阻力急剧增大．     

pH和氮素对球等鞭金藻胞外碳酸酐酶活性的影响

采用pH电极法研究pH和氮素对球等鞭金藻胞外碳酸酐酶活性的影响．结果表明,球等鞭金藻具有基本的胞外碳酸酐酶活性,且pH和氮素均能明显地诱导其胞外碳酸酐酶活性．pH从6．5升高到9．0时,球等鞭金藻胞外碳酸酐酶活性明显增加,pH8．5时酶活性达到最大．球等鞭金藻的pH补偿点为9．86,表明其具有利用HC03-的能力．氮素对胞外碳酸酐酶活性诱导也具有重要的影响,3种氮素NH4Cl、NaNOM3、CO（NH2）2在2．0mmoL／L时诱导的酶活性均明显高于8．5mmoL／L时的诱导的酶活性,且有机氮诱导的酶活性明显大于无机氮诱导的酶活性,硝态氮诱导的酶活性大于氨态氮诱导的酶活性．     

Chaperone-like features of bovine serum albumin: a comparison with α-crystallin

The chaperone behaviour of bovine serum albumin was compared with that of α-crystallin. The chaperone activity was assessed by measuring: (i) the ability to antagonize protein aggregation induced by heat; (ii) the capability to protect the activity of thermally stressed enzymes and (iii) the effectiveness in assisting the functional recovery of chemically denatured sorbitol dehydrogenase. Despite the lack of structural analogies, both proteins show several functional similarities in preventing inactivation of thermally stressed enzymes and in reactivating chemically denatured sorbitol dehydrogenase. As with α-crystallin, the chaperone action of bovine serum albumin appears to be ATP independent. Bovine serum albumin appears significantly less effective than α-crystallin only in preventing thermally induced protein aggregation. A possible relationship between chaperone function and structural organization is proposed. Together, our results indicate that bovine serum albumin acts as a molecular chaperone and that, for its particular distribution, can be included in the extracellular chaperone family. Received 29 August 2005; received after revision 23 September 2005; accepted 12 October 2005     

牛磺酸抗心肌成纤维细胞增殖作用的实验研究

目的研究牛磺酸(Taurine,Tau)对血管紧张素Ⅱ(angiotensinⅡ,AngⅡ)诱导新生大乳鼠心肌成纤维细胞(myofibroblasts,myo Fbs)增殖的抑制作用,并探讨其作用机制.方法用AngⅡ诱导新生大乳鼠myo Fbs增殖,建立心肌纤维化(myofibrosis,MF)模型.采用四甲基偶氮唑盐(MTT)法检测细胞增殖;羟脯氨酸试剂盒检测胶原含量;免疫细胞化学染色检测p-PKCα的膜转位及表达;Western blot检测p-PKCα和p-ERK1/2蛋白表达及含量.结果 Tau(30,60,120)mmol/L可明显抑制AngⅡ诱导的Myo Fbs增殖及胶原合成,同AngⅡ组比较差异具有统计学意义(P0.05或P0.01),并且呈现出剂量依赖性.应用免疫细胞染色Western blot并且结合图像分析,结果表明:Tau可抑制p-PKCα膜转位和表达,与AngⅡ组相比差异具有统计学意义(P0.01).结论 Tau可能通过减少p-PKCα的表达及膜转位,从而抑制MyoFbs增殖和胶原含量的增加,抑制MF,逆转心肌重塑.     

粒毛盘菌YMU50多酚发酵与纯化

文章研究了不同浓度的SNP对粒毛盘菌YMU50胞外多酚(LTEP)积累的影响及LTEP纯化工艺。与对照组相比,0.05mmol/L SNP与0.10mmol/L SNP浓度处理下LTEP最大积累量(第8天)分别提高了6.06%和12.12%,而0.20mmol/L SNP浓度处理下,LTEP积累量低于对照组。研究表明,通过筛选得到80~100目聚酰胺树脂对LTEP的静态吸附性能与解吸效果最好。利用80~100目聚酰胺树脂对LTEP进行纯化,单因素试验结果表明,最优吸附条件为:上样质量浓度为2mg/mL,pH值为4,速率为1BV/h;最优解吸条件为:乙醇体积分数为20%,洗脱液流速为1BV/h,乙醇用量为500mL,洗脱液pH值为8.5。采用Box-Behnken组合设计优化解吸条件,得到最优解吸条件为:乙醇体积分数为18%,洗脱液流速为0.98BV/h,乙醇用量为599.99mL,洗脱液pH值为9。在最优吸附与解吸条件下得到的LTEP的纯度为75.45%。     

Isolation, chemical characteristics and immunity activity of an extracellular polysaccharide EPSⅠ isolated from Antarctic bacterium Pseudoalteromonas sp. S-15-13

A new extracelluar polysaccharide (EPS) was isolated and purified from Antarctic bacterium S-15-13, identified as Pseudoalteromonas sp. After being separated and purified by DEAE-Sephadex A-50 ionexchange and Sephadex G-100 gel chromatography, two mains fractions (EPSⅠand EPSⅡ) were obtained. EPSⅠwas composed of mannose, glucose and galactose with a molecular weight of 23kDa and EPSⅡwas composed of mannose only with a molecular weight of 62kDa.The effect of the polysaccharide EPSⅠ on the cellular immune response of mice was investigated. Results demonstrated that EPSⅠ could markedly facilitate lymphocyte proliferation, and might be a strong immunomodulator.