Heterologous expression of amylase gene from Saccharomycopsis fibuligera in an industrial strain of Saccharomyces cerevisiae

An α-amylase encoding gene was amplified by polymerase chain reaction fromSaccharomycopsis fibuligera and inserted into a shuttle vector YEp352, together with the yeast phosphoglycerate kinase 1 promoter and α-factor signal gene. The recombinant expression plasmid pLA8α was transformed into an industrial strain ofSaccharomyces cerevisiae Sc-11. The activity of the α-amylase produced by the transformant Sc-11-pLA8α was 6.3 U/mL and the starch utilization rate in YPS medium was 42%. The purified amylase was analyzed by SDS-PAGE, showing a molecular weight of 55×10³ protein band. Furthermore, the residual sugar, ethanol and some volatile compounds in the fermented worts under simulating brewing conditions were determined by chromatographic analyses. The fermentation characteristics of Sc-11-pLA8α were similar to that of Sc-11 and only minor changes in the concentration of flavor compounds could be observed. Foundation item: Supported by the National Tenth Five-Year Hi-Technique Project (2001BA708B05-04). Biography: LIU Zeng-ran (1964-), fenale, Ph. D., research, direction: food and biotechnology.     

Cloning and Characterization of the fecC Gene Necessary for Optimal Growth under Iron-Deficiency Conditions in the Cyanobacterium Anabaena sp. PCC 7120

The fecC gene encoding a putative iron (Ⅲ) dicitrate transporte rwas cloned from nitrogen-fixing cyanobacterium Anabaena sp. PCC 7120, and inactivated. The mutant grows normally in medium with NO3^- , NH1^- or without combined nitrogen. But in iron-deficient medium, the mutant grows slowly. Photosynthetic properties were compared between the mutant and the wildtype strain, the content of photosynthetic pigments in the mutant is lower than that of the wild-type. The results of RT-PCR experiments show that the fecC gene is expressed under iron-deficient conditions, but is not expressed under iron-replete conditions. These results revealed that fecC gene product is required for optimal growth under iron-deficient conditions in Anabaena sp. PCC 7120.     

Evolutionary mode of metallothioneins inferred from Cd-MT genes of Tetrahymena

FromTetrahymena thermophila (strain BF5), the coding region ofCd-MT gene was cloned and sequenced, and identified as MTTI isoform. A serial duplicate structure is discovered in its amino acid sequence, which separates the coding region into three parts (Part 1: 7–61: Part 2: 64–118; Part 3: 122–162). The alignments among them and comparison with the corresponding parts of MT1 isoform suggest that MT1 and MTT1 isoforms both come from the same ancient gene that is homologous to Part 1, and Cd-MTs ofTetrahymena are aroused by such ancient gene duplication. The prediction of secondary structures and the analysis of the disulfide-bonding state of cysteine show that there are a lot of differences between MT1 and MTT1 isoforms, which maybe relate to their function mechanism. Foundation item: Supported by KSCX of Chinese Academy of Sciences Grant (SW-102) and the Allocation from the Earmaarked Grant for Hong Kong. Biography: WAN Mingliang (1980-). male, Ph. D. candidate, research direction: molecular ecotoxicology of protozoan.     

产丁醇大肠杆菌工程菌的构建

【目的】为了在大肠杆菌(Escherichia coli)中导入改良的丁醇合成途径,使非生产菌株大肠杆菌具备产丁醇的能力。【方法】克隆大肠杆菌乙酰转移酶基因atoB和丙酮丁醇梭菌(Clostridium acetobutylicum)丁醇合成途径关键酶基因(crt、hbd、adhE),构建多顺反子表达质粒pSE380-atoB-adhE-crt-hbd;克隆齿垢密螺旋体(Treponema denticola)反式烯酰辅酶A还原酶基因ter,构建表达质粒pSTV29-ter,并将双质粒导入到大肠杆菌。【结果】构建的工程菌能半厌氧发酵产微量丁醇,产量为0.08g/L。【结论】大肠杆菌中的丁醇合成途径导入成功,构建了产丁醇的大肠杆菌工程菌。     

A note on m -weights of linear codes

m-weight, as a new generalization of classical Hamming weight, was discussed in this paper. A condition for the existence of linear codes of certainm-weights was given; the Singleton bound, Plotkin bound and Sphere Parking bound of Hamming weight were correspondingly generalized to them-weight. Foundation item: Supported by the National Program on Basic Sciences (973 Program, G1999075102) Biography: YUAN Yuan (1979-), female, Ph. D candidate, research directions: combination and codes.     

蓝猪耳的显微鉴定

目的对蓝猪耳的显微特征进行研究。方法采用石蜡切片、粉末制片对蓝猪耳的茎、叶横切面组织显微结构及粉末特征进行研究。结果茎横切面四方形,四棱处向外凸起呈三角形,皮层内侧为一层扁平排列紧密的细胞,韧皮部较窄,外侧有纤维散在,断续排列成行,木质部于四角处较发达,导管多径向排列,髓部宽广;叶上下表皮细胞垂周壁弯曲,气孔不等式,栅栏组织1列,主脉维管束外韧形,半月形。结论上述特征可作为蓝猪耳显微鉴定的依据。     

Stable initialization scheme for K -means clustering

Though K-means is very popular for general clustering, its performance which generally converges to numerous local minima depends highly on initial cluster centers. In this paper a novel initialization scheme to select initial cluster centers for K-means clustering is proposed. This algorithm is based on reverse nearest neighbor (RNN) search which retrieves all points in a given data set whose nearest neighbor is a given query point. The initial cluster centers computed using this methodology are found to be very close to the desired cluster centers for iterative clustering algorithms. This procedure is applicable to clustering algorithms for continuous data. The application of proposed algorithm to K-means clustering algorithm is demonstrated. Experiment is carried out on several popular datasets and the results show the advantages of the proposed method. Foundation item: Supported by the National Natural Science Foundation of China (60503020, 60503033, 60703086), the Natural Science Foundation of Jiangsu Province (BK2006094), the Opening Foundation of Jiangsu Key Laboratory of Computer Information Processing Technology in Soochow University (KJS0714) and the Research Foundation of Nanjing University of Posts and Telecommunications (NY207052, NY207082)     

Deviation inequality for the number of k -cycles in a random graph

We study the number of k-cycles in a random graph G(n, p). We estimate the probability that a random graph contains more k-cycles than expected. In this case, the usual martingale inequality with bounded difference is not effective. By constructing a variable that approximates to the number of k-cycles in a random graph and using a new and extensive martingale inequality, we get the results in this paper. Foundation item: Supported by the National Natural Science Foundation of China (10571139)     

Evolution of the serum resistance-associated SRA gene in African trypanosomes

Serum resistance-associated (SRA) protein, a protein unique for Trypanosoma brucei rhodesiense, is responsible for resistance of this parasite to the lysis by normal human serum (NHS) and is a vital molecular marker to distinguish this species from other African trypanosomes. We cloned and sequenced the SRA basic copy (SRAbc) gene from T. b. rhodesiense and related species and found that this gene is confined to the subgenus Trypanozoon. The average 82% identity among the sequenced SRAbc genes indicates that they may have a common origin and are highly conserved. Since SRAbc coexists in the T. b. rhodesiense genome with SRA, we propose that SRAbc might be the ‘donor VSG’, which after duplication became inserted into the expression site by recombination. Under natural selection, SRAbc could reform into SRA following mosaic formation. Supported by National Natural Science Foundation of China (Grant Nos. 30570245, 30670275), Changjiang Scholars and Innovative Research Team in University (Grant No. DPCKSCU/IRT0447), International Foundation for Science of Sweden (Grant No. B/4318-1), Grant Agency of the Czech Republic (Grant No. Z60220518) and Education Foundation of the Czech Republic (Grant No. 2B06129)     

广西红树林区有孔团水虱的卵子发生

摸清有孔团水虱的繁殖特性,对团水虱的防控和消杀,以及保护红树林生态系统具有重要意义。本研究采用组织切片技术,研究广西红树林区有孔团水虱的卵子发生过程,探讨其繁殖期时间。结果表明,有孔团水虱的卵子发生过程可分为4个时期,分别是卵原细胞、无卵黄卵母细胞、卵黄发生卵母细胞和成熟期卵母细胞。其中：无卵黄卵母细胞又可分为前期、中期和后期3个亚期;卵黄发生卵母细胞可分为卵黄开始沉积时相和卵黄充满时相2个亚期。受精后发育的胚胎存在于母体内。周年调查表明：有孔团水虱雌性体内全年存在着各时期的卵母细胞或胚胎;2-3月无成熟期卵母细胞或胚胎出现。结合全年各期卵母细胞分布以及胚胎和幼体情况判断,广西红树林区有孔团水虱的繁殖期为每年的4月至次年的1月。     

博落回生物碱成分及其抗菌活性的研究

为研究罂粟科植物博落回的生物碱成分,采用硅胶柱层析、重结晶等方法对其进行了分离纯化,结果获得了5个生物碱,分别经波谱分析鉴定为:原阿片碱(I),pancorine(II),去甲基白屈菜红碱(III),6-丙酮基二氢血根碱(IV),6-丙酮基二氢白屈菜红碱(V),其中化合物(II)为首次从该植物中分离得到.抗菌圈检测发现博落回总生物碱抗菌作用较强,对金黄色葡萄球菌的抑制作用尤为显著.     

基于生物信息数据库分析TEFM基因在DLBCL中表达研究

为了探讨线粒体延伸因子TEFM在弥漫性大B细胞淋巴瘤DLBCL中的表达,初步研究其表达与DLBCL患者的临床特征及预后的关系,从数据库中下载关于DLBCL患者TEFM mRNA二代测序数据及临床病理资料,分析TEFM转录水平与临床病理参数的相关性及其预后价值.结果显示TEFM在DLBCL组织中均较正常淋巴组织显著高表达...     

巴戟天药材中耐斯糖含量近红外光谱测定方法的建立

目的建立巴戟天药材中耐斯糖含量的近红外光谱测定方法。方法用高效液相色谱法测定114批巴戟天药材中耐斯糖含量,采集近红外光谱后,运用多元散射校正法,结合最小偏二乘法建立巴戟天耐斯糖含量的定量模型。结果建立的耐斯糖近红外光谱定量模型,内部交叉验证决定系数为0.979 1,校正标准偏差为0.909 0,预测标准差为0.909 0,交叉验证的标准偏差为1.093 0。结论该含量测定近红外光谱模型稳定、准确适用于巴戟天药材中耐斯糖的含量测定。     

Expression of TGF-β2 in LECs of Age-Related Nuclear, Cortex Cataract and the Relationship among TGF-β2, Proliferation,Apoptosis and Transdifferentiation

0 IntroductionAsgue-br-eclaaptseudl acrat acraatcatr ianctc l,ud aems ocnogrte xwh,incuhcl,e acro ratnexdcataract and nuclear cataract are more i mportant .Cortex cataract is different from nuclear cataract inoccurring,developing and clinic display,evenin his-tology. The pathogenesis of age-related cataract hasnot been perfectly described.But it has been verifiedthat thereis alayer oflens epithelial cells (LECs) un-der vertebrates’lens anterior capsule, which is i m-portant in maintaining t…     

四元数矩阵方程AXB+CXD=E的M自共轭解

把实数域上的M对称矩阵的概念推广到四元数体上,形成M自共轭矩阵,然后在四元数体上讨论矩阵方程AXB+CXD=E的M自共轭解及其最佳逼近问题.利用四元数矩阵的实分解和复分解,以及M自共轭矩阵的特征结构,借助Kronecker积把约束四元数矩阵方程转化为实数域上的无约束方程,克服了四元数乘法非交换运算的困难,并得到该方程具有M自共轭解的充要条件及其通解表达式.同时在解集非空的条件下,运用矩阵的分块技术及矩阵的拉直算子,获得与预先给定的四元数矩阵有极小Frobenius范数的最佳逼近解.由于M自共轭矩阵是四元数自共轭矩阵的推广,因此所得结果拓展了该方程的结构解类型.     

Efficient transformation and expression of gfp gene in the edible mushroom Pleurotus nebrodensis

An efficient transformation method mediated by PEG-protoplasts was developed for the newly commercial edible mushroom Pleurotus nebrodensis. Two plasmids were used to co-transform protoplasts of P. nebrodensis. One plasmid is pAN7-1 containing a positive selectable marker gene hph conferring hygromycin B resistance. Another plasmid is pBlue-GFP containing a reporter gene gfp conferring green fluorescent protein. PCR and Southern blot analysis showed that hph gene or/and gfp gene were integrated into the genome of P. nebrodensis transformants. The transformation efficiency of the positive selectable marker gene hph was 3 transformants per microgram of plasmid pAN7-1 DNA, which was about 30 times higher than that previously reported in thoroughly studied Pleurotus species such as Pleurotus ostreatus. The transformation efficiency of the reporter gene gfp was 9 transformants per microgram of plasmid pBlu-GFP DNA. The co-transformation efficiency was 23.68%. This is the first report that a ＂reporter＂ gene, green fluorescent protein gene can be successfully stably exoressed in this Pleurotus species.     

Regulations of thyroid hormone on cardiac protein kinase C signal pathway in vitro

The experiments were conducted to assess the influences of thyroid hormone on cardiac protein kinase C(PKC) signal pathway with cultured cardiac myocytes and fibroblasts as the models. Cells were pretreated with 1% newborn calf serum (NCS) or angiotensin II (Ang II), and then following by a triiodothyronine (T3) treatment. The PKC activity, PKC_α and PKC_ε expressions were analyzed and compared. In 1% NCS pretreatment, T3 could inhibit PKC activity and PKC_ε expression in cardiac myocytes. The AngII pretreatment led to an increase of PKC activity and PKC_ε expression in cardiac myocytes, and an increase of PKC activity in cardiac fibroblasts. Following by T3 treatment, the increased PKC activity and PKC_ε expression in cardiac myocytes were markedly decreased. In conclusion, whether in 1% NCS or in Ang II pretreatment, T3 could inhibit PKC activity and PKC_ε expression in cardiac myocytes. Foundation item: Supported by the Natural Science Foundation of Hubei Province (98091) Biography: WANG Bao-hua (1974-), female, Ph. D, research direction: cardiovascular pathophysiology.