一株产生淀粉糖化酶的拟青霉

从土壤中分离筛选到一株降解生淀粉能力较强的菌株,通过固体发酵其生淀粉糖化酶活为2237U/g（按U/g麦麸计）,RDA值为15.25%。根据形态学特性初步鉴定该菌属于拟青霉属（Paecilomyces sp.）。其最适生长温度为30℃,最适生长起始pH5。其粗酶液24h水解生玉米淀粉的水解率为86.88%;对不同来源的生淀粉的水解能力不同,为玉米粉〉面粉〉米粉〉木薯粉〉甘薯淀粉;其最适作用pH为4,最适作用温度为70℃。     

假丝酵母Candidasp．发酵生产脂肪酶培养条件的优化

研究了碳源和氮源种类、碳源浓度以及起始pH值对假丝酵母Candidasp。菌株发酵生产脂肪酶的影响。结果显示,最适碳源为橄榄油,氮源为酵母膏,橄榄油浓度为2％,起始pH值为6.0。应用响应面试验设计对酵母膏、橄榄油和起始pH值进行培养基优化,结果表明,优化后的培养基配方为：橄榄油2.582％,酵母膏0.276％,K2HPO4 0.1％,MgSO4·7H2O 0.01％,NaCl 0.05％,pH6.28。在此条件下,假丝酵母Candidasp.液体发酵液中脂肪酶的酶活力可达36250U·mL^-1。     

转基因鱼腥藻7120流加培养的研究

流加培养对转TNF—α基因鱼腥藻7120的生长有利.单独流加碳源对转基因鱼腥藻7120生长与外源基因表达影响很小,单独流加氮源和同时流加碳氮源可明显促进生长,生物量达到2.964g/L和3.059g/L,分别增长9.91％和12.71％,而且能轻微促进藻细胞中的TNF表达.     

Characterization of an extracellular polysaccharide produced by Bacillus sp.RL-2

1 Introduction a Bioflocculation is a dynamic process resulting fromsynthesis of extracellular polymer by living cells.Flocculant are widely used in industrial processesincluding wastewater treatment, downstream pro-cessing, and food and fermentation processes [1-6].The flocculants used can be classified into three groups1) inorganic flocculants such as aluminum sulfate andpoly-aluminum chloride; 2) synthetic organic high-polymer flocculants such as polyacrylamide derivativesand polyethylene i…     

小球藻生物吸附废水中铜的研究

以小球藻作为生物吸附剂,去除水溶液中微量Cu~(2+),研究结果表明小球藻对Cu~(2+)的生物吸附主要经历了快速的吸附和缓慢的吸收两个步骤:pH值是影响Cu~(2+)生物吸附的一个重要影响因素,最佳pH值在6～8之间;离子强度对Cu~(2+)的吸附有一定的抑制作用;小球藻对Cu~(2+)的生物吸附符合Freundlich等温方程。     

Analysis of both chitinase and chitosanase produced by <Emphasis Type="Italic">Sphingomonas</Emphasis> sp. CJ-5

A novel chitinolytic and chitosanolytic bacterium, Sphingomonas sp. CJ-5, has been isolated and characterized. It secretes both chitinase and chitosanase into surrounding medium in response to chitin or chitosan induction. To characterize the enzymes, both chitinase and chitosanase were purified by ammonium sulfate precipitation, Sephadex G-200 gel filtration and DEAE-Sepharose Fast Flow. SDS-PAGE analysis demonstrated molecular masses of chitinase and chitosanase were 230 kDa and 45 kDa respectively. The optimum hydrolysis conditions for chitinase were about pH 7.0 and 36 °C, and these for chitosanase were pH 6.5 and 56 °C, respectively. Both enzymes were quite stable up to 45 °C for one hour at pH 5~8. These results show that CJ-5 may have potential for industrial application particularly in recycling of chitin wastes.     

一株高产黑色素链霉菌的分离筛选和初步鉴定

从鄱阳湖草洲土壤中分离出一株高产黑色素的细菌(g2B),g2B具有产黑色素速度较快,并且不需要Tyr诱导等优点.在同等条件下其产黑色素能力最强,经提取纯化后产量可达19mg/mL.纯化后的黑色素的红外光谱与SIGMA公司标准黑色素红外光谱图谱基本一致.生理生化分析结果及16s rDNA扩增和序列分析鉴定其种属类型,初步鉴定g2B属于Streptomyces sp..     

云南牛蛭部分基因注释及功能分类

以南美水蛭抗凝血Xa因子mRNA为模板设计引物,利用RT-PCR随机克隆云南牛蛭（P.yunnanensis.sp.nov）相关基因,结果得到多条片段,经严格筛选和鉴定后,确定大于200 bp ESTs序列,通过对这些ESTs序列进行聚类、拼接,结果得到10条片段,Genebank注册号分别为HQ285410,HQ285411,HQ285412,HQ285413,HQ285414,HQ285415,HQ285416,HQ285417,HQ285418,HQ285419.以上获得的云南水蛭头部和身体细胞部分转录的ESTs片段均与南美水蛭有较大差异,表明云南水蛭与南美水蛭可能使用完全不同的抗凝血机制.     

铁钉菜和珊瑚藻提取物抗菌活性的初步研究

采用圆纸片法对铁钉菜、珊瑚藻粗提取物及萃取得到的不同极性组分进行抗菌实验．结果表明：铁钉菜和珊瑚藻均有不同程度的抗菌作用,其中铁钉菜和珊瑚藻提取物的抗细菌活性较强,而对真菌几乎没有抑菌作用．     

马鞭草中总黄酮的超声波辅助提取及其抗氧化活性研究

采用正交试验设计研究超声波辅助提取马马鞭草中总黄酮的工艺条件,并对马鞭草中黄酮类化合物的抗氧化活进行测定.结果表明,马鞭草中总黄酮的最佳超声提取工艺条件为乙醇溶液体积分数70%、固液比1∶40(g/mL)、超声功率500 W、超声辅助提取温度70℃条件下提取20 min,在此条件下提取率可达2.87%.影响马鞭草中总黄酮提取效果的主次因素为:固液比>超声波功率>提取温度>乙醇体积分数.马鞭草黄酮类化合物具有清除羟自由基、超氧阴离子自由基的作用,其清除效果在一定范围内随着黄酮类化合物质量浓度的增加而增强.     

<Emphasis Type="Italic">Mrakia psychrophila</Emphasis> sp. nov., a new species isolated from Antarctic soil

The yeast strain （Y18） was isolated from a soil sample collected from Fildes Peninsula, Antarctica. The strain is a psychrophilic yeast with optimum and maximum growth temperatures of 10 ℃ and 18 ℃, respectively. Teliospores were formed after 7 d on malt agar, when the germination of teliospores was observed. Both inositol and D-glucuronate were assimilated. Positive results of the DBB （diazonium blue B） color reaction, urease test, and starch formation were observed. The major CoQ is Qs. All results indicated that Y18 belongs to the genes of Mrakia. The 18S rDNA sequence analyses showed that Y18 is closely related to Mrakiafrigida. DNA-DNA relatedness study, and some biochemistry characteristics indicated that Y18 represents a new species for which Mrakia psychrophila sp. nov. is proposed.     

Cytocompatible cellulose nanofibers from invasive plant species Agave americana L. and Ricinus communis L.: a renewable green source of highly crystalline nanocellulose

In this study, the fibers of invasive species Agave americana L. and Ricinus communis L. were successfully used for the first time as new sources to produce cytocompatible and highly crystalline cellulose nanofibers. Cellulose nanofibers were obtained by two methods, based on either alkaline or acid hydrolysis. The morphology, chemical composition, and crystallinity of the obtained materials were characterized by scanning electron microscopy(SEM) together with energy-dispersive X-ray spectroscopy(EDX), dynamic light scattering(DLS), X-ray diffraction(XRD), and Fourier transform infrared(FTIR)spectroscopy. The crystallinity indexes(CIs) of the cellulose nanofibers extracted from A. americana and R. communis were very high(94.1% and 92.7%, respectively). Biological studies evaluating the cytotoxic effects of the prepared cellulose nanofibers on human embryonic kidney 293 T(HEK293 T) cells were also performed. The nanofibers obtained using the two different extraction methods were all shown to be cytocompatible in the concentration range assayed(i.e., 0-500 μg/mL). Our results showed that the nanocellulose extracted from A. americana and R. communis fibers has high potential as a new renewable green source of highly crystalline cellulose-based cytocompatible nanomaterials for biomedical applications.     

百姓的语言 睿智的思想——从《战争时代》看三十年代W．H．奥登的诗学策略

奥登作为英国20世纪30年代诗人的代表,在充满政治、经济危机的历史语境中采取不同于艾略特等现代主义诗人的诗学策略,以大众的语言赋思于诗.其十四行诗组诗<战争时代>用明白晓畅的语言.全面展现了30年代老百姓的生活与心理.深刻表达了对社会、战争的思索和对人类生存困境的关注.30年代奥登的诗学策略.影响了一代诗人.