Selection of Yarrowia lipolytica Strains with High Protein Content from Yeasts Isolated from Different Marine Environments

A total of 78 Yarrowia lipolytica yeast strains from seawater, sediments, mud of salterns, the guts of marine fish, and marine algae were obtained. After the crude protein of the yeasts was estimated by the method of Kjehldahl, we found that seven strains of the marine yeasts grown in soy bean cake hydrolysate with 20 g L-1 of glucose for 48 h at 28℃ contained more than 41.0 g protein per 100 g of cell dry weight and the cell dry weight was more than 4.4 g per L of the culture. Among them, strain SWJ-1b contained the highest crude protein. The results of Biolog identification and molecular methods further confirmed that they indeed belonged to Y. lipolytica.     

Screening and molecular classification of low-temperature protease from Antarctic microorganism and its characterization

107 strains producing protease were screened from 260 strains of Antarctic psychrophilic bacteria, among which proteolytic activity of five strains was more than 45 U ml^-1. The 16S rRNA gcne sequences homology and phylogcnetic analysis of five Antarctic psychrophillc bacteria showed that NJ276, NJS-9, NJ16-70,NJ345 belonged tO the described genus Pseudoalteromonas and NJ341 belonged to the genus Colwellia. The growth and the protease characteristic of four Antarctic psychrophilic bacteria had been studied, and the result showed that the 6ptimal temperature for growth and protease-produeing of four strains was about 10℃. Their growth and protease-produeing were still high during incubatlng 2-5 days. The maximum proteolytic activity occurred at pH 9 for four Antarctic psychrophilic bacteria. The optimal temperature of protease action of both strains NJ276 and NJ5-9 was about 50℃, however, the optimal temperature of protease aetlon of both strains NJ341 and NJ345 was about 40 ℃, and their proteolytic activity under 0℃ exhibited nearly 30% of the maximum activity, but their thermal stabilities were weaker. These results indicated that proteases from NJ341 and NJ345 were low-temperature proteases.     

2．5亿年前生物灭绝与古海洋透光层污染有关

中、澳、美等国科学家研究生物分子化石发现：2．5亿年前生物大灭绝与古海洋透光层的硫化氢污染有关。     

运用ITS基因分析大鹏半岛海域石珊瑚系统发育关系

通过ITS基因特异扩增测序,对大鹏半岛海域46种石珊瑚ITS基因片段序列进行了比较分析。结果表明,该片段序列长度在674~806碱基对(bp)之间,A、T含量在40%~55.5%之间,大部分物种的序列碱基A、T含量小于G、C含量。46种造礁珊瑚的平均遗传距离为0.261。采用邻位连接(NJ)和最小进化(ME)法分别构建15种复合型珊瑚的5.8S r DNA系统发育树和28种坚实型珊瑚的ITS2系统发育树,结果显示15种复合型珊瑚的5.8S r RNA序列系统进化聚类结果较符合传统形态学分类结果,而28种坚实型珊瑚的ITS2序列系统进化聚类结果与传统形态学存在较大的差异,提示石珊瑚表型的变异性可能对传统分类存在影响。     

The comparison between allozyme and RAPD makers for the population genetic structure analysis of scallop Chlamys farreri

1INTRODUCTION Since the first use in human genetic research in1966,allozyme has become the most popular genetic marker for population genetics studies for almost all groups of animals and plants(Lewontin and Hubby,1966;Murphy et al.,1996).In the past seve…     

草鱼种质退化相关SRAP分子标记的筛选

采用相关序列扩增多态性（sequence-reared amplified polymorphism，SRAP）技术分析野生草鱼和家养草鱼，并筛选与草鱼种质退化相关的分子遗传标记。共进行88对引物组合的检测，产生标记数目共计905个。依据标记在群体中出现的频率和变化规律，共筛选出21个可能与种质相关的特异性标记，对这些特异性标记进行测序并将测序结果进行BLAST分析，发现测得片段中有8个片段能在GeneBank中找到同源性较高的序列，而其他片段与数据库中序列的相似性较低。     

Genetic variation in two sea cucumber （Apostichopus japonicus） stocks revealed by ISSR markers

Sea cucumber Apostichopus japonicus samples were collected in Changdao, Penglai (PL), 27 individuals, and Lingshandao, Qingdao (QD), 30 individuals, in the Shandong Peninsula, China. Ten SSR primers were used to assess the genetic variation and relationship between and within the two stocks. Respectively, for each stock, the percentage of polymorphic bands was 85.2% and 86.9%; the gene diver- sity was 0.360 5 and 0.342 8; and the Shannon’s information index was 0.515 0 and 0.499 0. At species level, the percentage of polymorphic bands was 92.2%, the total gene diversity was 0.378 9 and the Shannon’s information index was 0.550 4. The coefficient of overall genetic differentiation and the ge- netic distances between the stocks were also calculated to be 0.073 0 and 0.079 6 using the POPGENE program. Results show that the genetic diversity of the two stocks is still large but the genetic distance between the two stocks is close. A dendrogram was constructed for the 57 individuals from the two stocks, showing that the genetic structure was unitary for PL stock but complex for QD stock.     

Application of the clustering method in molecular dynamics simulation of the diffusion coefficient

Using molecular dynamics （MD） simulation, the diffusion of oxygen, methane, ammonia and carbon dioxide in water was simulated in the canonical NVT ensemble, and the diffusion coefficient was analyzed by the clustering method. By comparing to the conventional method （using the Einstein model） and the differentiation-interval variation method, we found that the results obtained by the clustering method used in this study are more close to the experimental values. This method proved to be more reasonable than the other two methods.     

氮氧化物大气简易采样法研究

氮氧化物大气简易采样法 ,无需动力装置 ,小巧、价廉、操作方便 ,受环境条件限制少 ,尤其适用于环境调查。本方法利用分子扩散原理捕集大气中的氮氧化物 ,然后用分光光度方法测定。结果准确性高。     

高山榕叶斑病菌的分离及鉴定

从高山榕(Ficus altissima Bl.)叶斑病的病叶上分离到一株真菌,经接种鉴定为高山榕叶斑病的病原物。通过形态学观察,发现该病原物为链格孢属(Alternaria sp.)。利用直接菌落PCR测定了此病原物的核糖体DNA的转录间区、内聚半乳糖醛酸酶基因以及基因组中OPA1-3区域的DNA。结合序列分析和形态学观察结果,该菌鉴定为A.gaisen。     

基于线粒体16SrRNA基因的14种造礁石珊瑚系统发育关系分析

通过16SrRNA基因特异扩增测序,对惠州大亚湾大辣甲岛和小辣甲岛附近海域14种造礁石珊瑚16SrRNA基因片段序列进行了比较分析。结果表明,该片段序列的平均A+T含量为63.5%,所有物种的序列碱基AT含量大于GC含量,序列都处于高度饱和的状态。14种造礁石珊瑚的平均遗传距离为0.179。采用NJ、ML和ME法构建系统发育树,结果显示蜂巢珊瑚科单独作为分支处于发育树的基部,而第二支分支包括菌珊瑚科、鹿角珊瑚科、滨珊瑚科和枇杷珊瑚科。裸肋珊瑚科的腐蚀刺柄珊瑚聚到了蜂巢珊瑚科中,与传统形态学分类存在差异,提示造礁石珊瑚表型的变异性可能对传统分类存在影响。     

CONVERSION RATES OF SURFACE HOX RADICALS IN BEIJING CITY

1INTRODUCTIONThe hydroxyl radicals play a central role in atmospher-ic photochemistry, reacting with a lot of compounds, often initiating their oxidation and subsequent loss and resulting in the formation of ozone and other deleteri-ous oxidants, acids, and fine particles in polluted ar-eas. A thorough understanding of this role is necessary for efficient, cost-effective pollution control. There-fore, the measurement of OH is very significant (E-HHAT etal., 1991). Nevertheless, most me…     

Molecular survey of sulphate-reducing bacteria in the deep-sea sediments of the west Pacific Warm Pool

The sulfate-reducing bacteria (SRB) community in the deep-sea sediments of the west Pacific Warm Pool (WP) was surveyed by molecular phylogenetic analyses using primers targeting the 16S rRNA gene fragments of SRB. Specific 16S rRNA gene libraries from five sediment layers (1-cm, 3-cm, 6-cm, 10-cm and 12-cm layer) of the 12-cm core of WP-0 were constructed. The clones in the five libraries were differentiated by restriction fragment length polymorphism (RFLP) and representative clones were selected to sequence. It was found that the clones fell into four groups, which were closest related to Desulfotomaculum, Desul- facinum, Desulfomonile and Desulfanuticus. Desulfacinum-like clones were only detected in the upper layers of the sediment core, whereas Desulfomonile-like clones were only present in the deeper layers. Fluorescence in situ hybridization (FISH) was further carried out to visualize and count the SRB and bacteria in the five sediment layers. It was found that SRB constituted only a small proportion of the bacteria community (0.34%-1.95%), it had the highest content in the 3-cm layer (1.95%) and had a depth- related decreasing tendency along the 12- cm core.     

黄鳍鲷生长激素cDNA的分子克隆和序列分析

生长激素 (ｇｒｏｗｔｈｈｏｒｍｏｎｅ,ＧＨ)是脊椎动物脑垂体细胞合成和分泌一种单链多肽激素 ,具有促进鱼类生长 ,加速蛋白质的合成 ,提高饲料转化率 ,调节海河洄游性鲑科鱼类的渗透压 ,促进鲑科鱼类对海水的适应能力 ,提高鱼类血液、腺体和肾脏中淋巴细胞的抗病毒能力 ,从而增强鱼体的抗感染能力等作用 ,被认为是最有效的生长促进剂之一 ,具有重要的潜在应用价值。目前 ,国内外已有40多种鱼类的ＧＨ基因被分离和克隆[1,2 ] ,序列分析表明 ,ＧＨ与泌乳刺激素 (ＰＲＬ)、胎盘催乳素(ＰＬ)、生长催乳素 (ＳＬ)具有相似的结构和交叉的功能 ,…     

日本囊对虾的遗传育种研究进展

日本囊对虾是我国优质对虾资源。综述日本囊对虾(Marsupenaeus japonicus)的种质资源、选择育种、多倍体诱导育种、分子标记辅助育种等方面的研究进展,总结虾类杂交育种、转基因育种研究现状,对日本囊对虾相关研究进行展望;针对当前日本囊对虾遗传育种研究落后、数量遗传学应用不够、育种工艺不足的现状,认为在日本囊对虾遗传改良时,应用高新分子标记辅助育种技术与传统选择育种相结合的综合育种技术是良种培育的有效途径。     

页岩黏土矿物CH_4/CO_2吸附规律的分子模拟

CH4和CO2在页岩黏土矿物中的吸附行为对页岩气的开采和CO2的封存具有重要意义。选取黏土矿物的主要成分蒙脱石为研究对象,构建层状裂缝型孔隙的分子模型,采用巨正则系综蒙特卡洛(GCMC)方法和分子动力学(MD)方法,在不同压力、不同温度条件下,研究不同狭缝孔隙宽度CH4和CO2气体的吸附行为,同时分析离子交换结构对吸附的影响。结果表明:CH4吸附符合Langmuir吸附规律,可以采用Langmuir方程进行拟合。随着温度的升高两种气体吸附量减小,随着压力的增大而增大;蒙脱石的离子交换结构对CH4的吸附影响较小,但促进对CO2的吸附;不同的狭缝孔隙宽度对应CH4和CO2的赋存状态不同,蒙脱石的离子交换结构影响CO2的赋存状态;平均作用势说明吸附层中分子间结合能力大于游离层,吸附态是CH4和CO2在蒙脱石狭缝中的主要赋存形式之一。基于CH4和CO2在页岩黏土矿物中的吸附规律,可为页岩气的勘探开发提供依据。     

草鱼种质退化相关SRAP分子标记的筛选

采用相关序列扩增多态性(sequence-realted amplified polymorphism,SRAP)技术分析野生草鱼和家养草鱼,并筛选与草鱼种质退化相关的分子遗传标记。共进行88对引物组合的检测,产生标记数目共计905个。依据标记在群体中出现的频率和变化规律,共筛选出21个可能与种质相关的特异性标记,对这些特异性标记进行测序并将测序结果进行BLAST分析,发现测得片段中有8个片段能在GeneBank中找到同源性较高的序列,而其他片段与数据库中序列的相似性较低。     

罗非鱼鱼皮肽的体外ACE抑制活性、消化性及分子对接对比

【目的】分析罗非鱼鱼皮多肽LSGYGP的ACE抑制活性、胃肠道消化稳定性以及与降压药卡托普利在分子对接的对比。【方法】用HHL法测定多肽的IC50值和抑制模式,测定多肽在模拟胃肠道消化中的稳定性,MTT法检测细胞活力,Western blot法检测诱导型一氧化氮合酶(i NOS)、环氧合酶-2(COX-2)、内皮素-1(ET-1)等蛋白表达情况,将多肽、卡托普利分别与ACE进行分子对接对比分析。【结果】LSGYGP的半抑制率(IC50)值为2.57μmol/L,表现为混合非竞争性抑制,4 h内模拟胃肠道消化较为稳定;MTT法验证多肽LSGYGP对HUVEC细胞无毒性作用(P 0.05),且能明显提高Ang Ⅱ诱导组的HUVEC细胞活力(P 0.01);与对照组相比,随实验组多肽浓度增加,i NOS、COX-2和ET-1的表达明显逐渐减少(P0.001)。对接结果表明,氢键是LSGYGP与ACE结合结构中的支撑力,而卡托普利通常与ACE的Zn~(2+)离子形成紧密结合的相互作用。【结论】消化稳定的罗非鱼鱼皮多肽可明显抑制血管收缩因子和炎症因子的表达,展现了较好ACE抑制活性,LSGYGP与卡托普利的活性差异可能是由于ACE分子对接的作用力不同,这些可作为研发少副作用ACE抑制剂的药理基础。     

放射性碳同位素技术在碳质气溶胶源解析中的应用研究进展

碳质气溶胶是大气气溶胶的重要组成部分,能够影响太阳辐射在大气层中的正常传播,与气候变化、空气污染和人类健康等关乎人类可持续发展的重要问题密切相关。大气环境中的碳质气溶胶主要包含有机碳和元素碳,其中有机碳可分为水溶性有机碳和非水溶性有机碳。碳质气溶胶的来源及其形成转化过程是目前大气环境科学领域最为重要的研究方向之一。放射性碳同位素比值(Δ¹⁴C)在碳质气溶胶源解析上具有优势,是目前唯一可以量化化石源和生物源在不同类别碳质组分中贡献大小的手段。在系统总结国内外放射性碳同位素技术在碳质气溶胶源解析上的最新研究进展的基础上,详细阐述了放射性碳同位素比值在碳质气溶胶源解析上的应用原理,深入探究了放射性碳同位素比值在碳质组分中的研究进展,重点分析了单体分子放射性碳同位素分析在碳质气溶胶中的发展和应用。最后,对放射性碳同位素比值与稳定碳同位素比值(δ¹³C)联用,以及单体分子标志物的放射性碳同位素比值研究进行了展望,为碳质气溶胶的来源解析和气溶胶化学过程研究提供参考依据。