Proton transfer kinetics of 5′-deoxypyridoxal

The kinetics of the isomerizaton between the zwitterion and the unpolar form of 5′-deoxypyridoxal in its monoprotonated state have been studied by means of the T-jump technque; and the equilibrium constant of the isomerization process has been determined.Several parallel reactions contribute to the kinetics of interconvention: a direct intramolecular proton transfer and proton exchange with H₃O⁺, OH^?, the totally protonated and the totally depronated 5′-deoxypyridoxal molecule.The Rate constants for these parallel reactions are evaluated from the measured relaxation times. They are discussed in the light of general aspects of proton transfer reactions.     

Comparison between Culture and a Multiplex Quantitative Real-Time Polymerase Chain Reaction Assay Detecting Ureaplasma urealyticum and U. parvum

A novel multiplex quantitative real-time polymerase chain reaction (qPCR) for simultaneous detection of U. urealyticum and U. parvum was developed and compared with quantitative culture in Shepard''s 10 C medium for ureaplasmas in urethral swabs from 129 men and 66 women, and cervical swabs from 61 women. Using culture as the gold standard, the sensitivity of the qPCR was 96% and 95% for female urethral and cervical swabs, respectively. In male urethral swabs the sensitivity was 89%. The corresponding specificities were 100%, 87% and 99%. The qPCR showed a linear increasing DNA copy number with increasing colour-changing units. Although slightly less sensitive than culture, this multiplex qPCR assay detecting U. urealyticum and U. parvum constitutes a simple and fast alternative to the traditional methods for identification of ureaplasmas and allows simultaneous species differentiation and quantitation in clinical samples. Furthermore, specimens overgrown by other bacteria using the culture method can be evaluated in the qPCR.     

云南金平分水岭国家级自然保护区苔类植物物种多样性

自2015年至2018年对云南金平分水岭国家级自然保护区的苔藓植物进行野外考察、标本采集及鉴定,统计该地区苔类植物34科60属203种(含种下分类单元)。对自然保护区苔类植物物种进行多样性分析,结果显示,细鳞苔科(57种)和羽苔科(34种)所包含物种数量最为丰富;平铺型是本调查区的优势生活型类型;从物种的区系组成来看,广义的热带成分比重最大,达40.4%。     

中国2种归化植物新记录

报道了发现于辽宁省的2种中国归化植物新记录:白毛马鞭草(Verbena stricta Vent.)和向日葵(Helianthus annuus L.),白毛马鞭草穗状花序粗壮而紧凑,单生枝顶或呈简单的聚伞状或圆锥状排列,且花序轴在果期显著延长,叶卵圆形,无柄,与中国有报道的本属其他物种区别明显。该种原产美国西部至中部地区,近来在辽宁省铁岭市发现有归化。向日葵原产于北美地区,被发现广泛归化于辽宁省大连市,营口市鲅鱼圈也有发现。归化种群形态特征与该地区栽培类型完全不同,其花序极多分枝,头状花序直径较小,瘦果极小,表面纹饰多样性很高。     

Fusarium oxysporim M1菌株的rDNA ITS鉴定及其纤维素酶活性及纯化研究

以1株分离于北大仓白酒大曲的产纤维素酶真菌M1为材料,对其进行了形态及分子生物学鉴定;纯化并研究了其纤维素酶的酶学性质。以真菌ITS1/ITS4通用引物,扩增真菌M1的rDNA ITS序列,再与GenBank中其他菌株rDNA ITS序列进行比对,使用Mega5.0软件,采用最大似然法进行聚类分析。结果显示,该真菌同已经报道的Fusarium oxysporim strain Bt3聚为一类,一致率达99%,与形态学方法鉴定一致,命名为Fusarium oxysporum M1。该菌具有很高纤维素酶活力,FPA和CMCA分别高达16.84 IU/mL和35.31 IU/mL。经过发酵条件优化酶活性进一步提高。经硫酸铵分级分离、疏水和离子交换层析,纯化了该菌纤维素酶,纯化倍数高达17.97倍,得率为3.676%,SDS-PAGE分析表明,该纤维素酶分子量达60 k Da。本研究为进一步研究该酶高效催化机理及实际应用提供参考。     

微藻降解废水污染物的研究进展

微藻在废水处理方面有着很好的开发潜能和极大的优势,在去除氮、磷、富集重金属和降解有毒有机物质的同时,还能作为食品添加原料和养殖饲料等。重点针对微藻的特点及类型、水处理体系的优缺点、废水中的应用及氮磷的去除、重金属离子的富集和难降解有机物的降解机理进行了介绍,并阐述了微藻处理废水中存在的问题及展望了该领域今后的研究方向。     

致病性副溶血性弧菌菌落杂交检测体系的优化

对常见食源性致病菌副溶血性弧菌的杂交条件进行了优化。基于副溶血性弧菌的tdh,trh,toxR基因选用了3种探针序列,从菌落杂交样品的预处理方法、杂交时间和显色检测等方面对基于副溶血性弧菌毒力基因的原位杂交实验进行了条件优化。结果表明,采用80℃热固定2 h,37℃预杂交10 min后杂交8 h以及封闭1 h的改良方法可获得高特异性、低背景且着色清晰的实验结果。优化的菌落杂交技术检测副溶血性弧菌与传统检测方法相比,具有高效、准确、可区分致病性菌株的优点,为水产品中副溶血性弧菌致病菌株和非致病菌株的同步检测和筛选提供参考。