‘Green tides’ are overwhelming the coastline of our blue planet: taking the world’s largest example

A broad spectrum of events that come under the category of green tide are recognized world-wide as a response to elevated levels of seawater nutrients in coastal areas. Green tides involve a wide diversity of sites, macroalgal species, consequences, and possible causes. Here we review the effect of natural and man-induced environmental fluctuations on the frequency and apparent spread of green tides. This article highlights the need for interdisciplinary research aimed at shedding light on the basic mechanisms governing the occurrence and succession of green algae in coastal seas. This will result in more effective management and mitigation of the effects of green tides, thus safeguarding the intrinsic and commercial value of coastal marine ecosystems.     

黄芪对镉致大鼠睾丸支持细胞超微结构及波形蛋白、E-钙粘蛋白表达改变的保护作用

目的 探讨黄芪对镉致大鼠睾丸支持细胞损伤的保护作用.方法 21只成年雄性SD大鼠随机分成镉组(0.1％氯化镉腹腔内注射,1mg/Kg体重/天,5天/周,处理后1、2、3、4周取材)、镉加黄芪组(注射氯化镉的同时注射黄芪,10g/Kg体重/天,5天/周,处理后2、4周取材)和对照组(腹腔内注射等量生理盐水).睾丸取材作光镜、免疫组织化学染色和图像分析及超微结构观察.结果 光镜H.E染色对照组支持细胞核不规则,染色浅,核仁明显,镉处理后胞浆内有空泡形成,镉加黄芪组支持细胞未见明显改变.对照组波形蛋白阳性产物在支持细胞靠近基室腔的胞浆中表达,E-钙粘蛋白阳性产物则主要定位于生精上皮近腔室的支持细胞和部分生精细胞胞浆中.镉处理后支持细胞胞浆中波形蛋白和E-钙粘蛋白阳性产物表达的平均光密度值均明显降低(P＜0.05),镉加黄芪组阳性产物表达虽较对照组减弱但明显高于相应镉组(P＜0.05).镉处理组支持细胞胞质特化区和紧密连接破坏,镉加黄芪组支持细胞超微病变较相应镉组为轻.结论 镉降低大鼠睾丸支持细胞波形蛋白和E-钙粘蛋白的表达并造成支持细胞的超微结构损伤,黄芪具有较好的保护效果.     

Crystal structure of a beta-catenin/Tcf complex

The Wnt signaling pathway plays critical roles in embryonic development and tumorigenesis. Stimulation of the Wnt pathway results in the accumulation of a nuclear beta-catenin/Tcf complex, activating Wnt target genes. A crystal structure of beta-catenin bound to the beta-catenin binding domain of Tcf3 (Tcf3-CBD) has been determined. The Tcf3-CBD forms an elongated structure with three binding modules that runs antiparallel to beta-catenin along the positively charged groove formed by the armadillo repeats. Structure-based mutagenesis defines three sites in beta-catenin that are critical for binding the Tcf3-CBD and are differentially involved in binding APC, cadherin, and Axin. The structural and mutagenesis data reveal a potential target for molecular drug design studies.     

九龙江河口浮游植物的时空变动及主要影响因素

于2009年春（5月）、夏（8月）、秋（11月）在九龙江河口水域进行了水文、化学和生物的生态完全示范区综合外业调查,研究了九龙江河口浮游植物的种类组成、密度分布、季节变化、空间差异及主要影响因素,并结合前期资料分析了年际变动。结果表明,九龙江河口的浮游植物共记录7个门类75属134种。主体是硅藻,绿藻次之,甲藻和蓝藻较少,黄藻检出率高,裸藻和金藻零星检出。种类组成的空间差异大,绿藻在河口内区淡水水域比硅藻更占优势, 中肋骨条藻（Skeletonema costatum）、短角弯角藻（Eucampia zodiacus）、圆筛藻（Coscinodiscus spp.）、颗粒直链藻（Melosira granulata）、微小小环藻（Cyclotella. caspia）是河口区咸淡水水域及近海区的主要种类。浮球藻（Planktosphneria gelotinosa）、栅藻（Scenedesmus spp.）、盘星藻（Pediastrim spp.）、小席藻（Phormidium tenus）是河口内区淡水水域的主要种类。根据浮游植物的生态类型及其生境特征大致可分为三大类群。浮游植物密度夏季最高,平均为358.68103cells/L,密集中心的季节变化明显,密度分布由优势类群的密度分布决定。中肋骨条藻和短角弯角藻的数量庞大,导致优势种突出,多样性降低,种间分布不均匀,群落结构简单化。与史料比对,种类组成因淡水藻类的列入而更丰富,密度年际降低,中肋骨条藻仍是第一优势种,但优势度有较大降幅,优势类群有重大年际变化,细胞个体较小的种类占优。盐度和营养盐对浮游植物的分布及密度变化造成极大的时空差异,存在线性、复合线性、多项回归等复杂的相关关系。     

马铃薯StSnRK2.1基因克隆与生物信息学分析

SnRK2基因对植物的逆境胁迫具有重要的调节作用,以马铃薯‘陇薯3号’(Solanum tuberosum)为试材,采用RT-PCR方法从马铃薯试管苗中克隆得到1个SnRK2.1基因cDNA,命名为StSnRK2.1,提交GenBank注册,注册号为JX280911。通过生物信息学分析,该基因开放阅读框全长1 008 bp,编码335个氨基酸。预测蛋白质分子量约为37.77 kD,等电点为5.37,蛋白质二级结构预测α-螺旋42.39%,延伸链16.42%,β-折叠7.46%,无规卷曲33.73%,具有疏水性,为膜内蛋白。亚细胞定位显示该基因出现在细胞质及微体中的可能性较大。肽链可能有7处丝氨酸磷酸化位点,2处苏氨酸磷酸化位点,以及3处酪氨酸磷酸化位点,因此推测该基因在植物抗逆中有重要的作用。     

GS3, a major QTL for grain length and weight and minor QTL for grain width and thickness in rice, encodes a putative transmembrane protein

The GS3 locus located in the pericentromeric region of rice chromosome 3 has been frequently identified as a major QTL for both grain weight (a yield trait) and grain length (a quality trait) in the literature. Near isogenic lines of GS3 were developed by successive crossing and backcrossing Minghui 63 (large grain) with Chuan 7 (small grain), using Minghui 63 as the recurrent parent. Analysis of a random subpopulation of 201 individuals from the BC₃F₂ progeny confirmed that the GS3 locus explained 80–90% of the variation for grain weight and length in this population. In addition, this locus was resolved as a minor QTL for grain width and thickness. Using 1,384 individuals with recessive phenotype (large grain) from a total of 5,740 BC₃F₂ plants and 11 molecular markers based on sequence information, GS3 was mapped to a DNA fragment approximately 7.9 kb in length. A full-length cDNA corresponding to the target region was identified, which provided complete sequence information for the GS3 candidate. This gene consists of five exons and encodes 232 amino acids with a putative PEBP-like domain, a transmembrane region, a putative TNFR/NGFR family cysteine-rich domain and a VWFC module. Comparative sequencing analysis identified a nonsense mutation, shared among all the large-grain varieties tested in comparison with the small grain varieties, in the second exon of the putative GS3 gene. This mutation causes a 178-aa truncation in the C-terminus of the predicted protein, suggesting that GS3 may function as a negative regulator for grain size. Cloning of such a gene provided the opportunity for fully characterizing the regulatory mechanism and related processes during grain development.     

Determining the involvement of two aminopeptidase Ns in the resistance of Plutella xylostella to the Bt toxin Cry1Ac: cloning and study of in vitro function

The cloning, expression in vitro, and characterization of two aminopeptidase Ns (APN5s and APN2s) isolated from the midgut of Cry1Ac-resistant (R) and susceptible (S) strains of Plutella xylostella larvae are presented in this paper. The deduced amino acid sequences of APN5s included C-terminal GPI-modification sites, the gluzincin aminopeptidase motif GATEN, and three N-glycosylated sites; those of APN2s had no GPI-modification sites, had gluzincin aminopeptidase motif GAMEN, and had four N-glycosylated sites. O-glycosylated sites were not predicted for either APN. Because APN2R and APN2S cDNAs contained the same nucleotides, only full-length cDNAs encoding APN5R and APN5S were expressed in Trichoplusia ni cells. Far-Western blotting showed that the expressed receptor APN5 bound to the Cry1Ac toxin. An enzyme-specific activity experiment also showed that APN5 genes were expressed in T. ni cells. ELISA revealed no differences in the binding of expression proteins from the resistant and susceptible strain with Cry1Ac.     

Application of radiation hybrid in gene mapping

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