西藏南部岗巴地区白垩纪中期钙质超微化石带和Cenomanian-Turonian界线

我国西藏南部海相白垩系含有较丰富的钙质超微化石。文中着重研究岗巴地区两个剖面 (即剖面A ,B)Albian Santonian钙质超微化石的分布。根据标志种的存在 ,识别出 5个初现面事件 ,相应地建立 6个钙质超微化石带 ,自下至上是Prediscosphaeracretacea带 ,Eiffellithusturriseiffeli带 ,Lithraphiditesacutum带 ,Gartneragoobliquum带 ,Quadrumgartneri带 ,Lucianorhabduscayeuxii带。同时 ,通过洲际对比 ,建议以G .obliquum初现面作为划分本区Cenomanian和Turonian界线的标志。此外 ,Q .gartneri带和I .cayeuxii带之间缺失多个化石带 ,据此推测Turonian至Santonian期间本区可能存在沉积间断。     

榆耳有性结构及生活史的研究

本文通过电镜扫描、石腊切片及用苏木精染色法和DAPI荧光染色,对榆耳子实体有性结构进行观察,证实榆耳子实体菌盖结构分三层:上表层为毛层,表面着生有排列较密集顶端游离的菌丝,它们相互粘连呈菌丝束;中间层为髓部,由较疏松而相互交织在一起的薄壁菌丝组成,菌丝间充满胶质物质;下表层为子实层,表面起伏不平,呈不规则的疣状突起,上面着生担子和囊状体,担子无隔膜棍棒形,外表有不规则的网状纹饰,其顶部着生4个瓶梗状小梗,每个小梗上着生1个椭圆形或腊肠形担孢子,大小为2.5—3.0×6.0—6.5μm,担孢子表面有不规则的网状纹饰结构。在担子间的囊状体为长圆柱形或圆锥形,表面有较密的不规则的网状纹饰。 榆耳有性生殖为异宗配合。绝大多数担孢子含一个细胞核,很少数担孢子含两个细胞核。孢子萌发为一端萌发,也有少数为两端萌发。初生菌丝单核,不能形成子实体,当两种不同遗传性的交配型的初生菌丝结合后,形成具有锁状联合结构的双核菌丝,并可发育成子实体。榆耳具有典型减数分裂过程,不具有减数分裂后核分裂行为,四个子核分别进入四个担孢子内。 在初生菌丝或次生菌丝上,均可产生间生的或顶生的厚垣孢子。经过温度、光照和紫外线照射的诱发,均未发现有其它类型的无性孢子产生。因此,榆耳菌的生活史和大多数担子     

热带假丝酵母脂肪醛脱氢酶基因CtAld1和CtAld2的功能评价

【目的】热带假丝酵母是发酵法生产二元酸的重要工业菌株,具有较高的ω-氧化活性。脂肪醛脱氢酶在ω-氧化途径中起重要作用,催化脂肪醛生成脂肪酸,但其具体催化功能及对细胞生理影响还未被系统研究。本文通过删除脂肪醛脱氢酶基因CtAld1和CtAld2鉴定了其在ω-氧化途径中的功能。【方法】通过基因组信息挖掘获得热带假丝酵母脂肪醛脱氢酶基因CtAld1和CtAld2序列,在此基础上,通过同源重组敲除CtAld1和CtAld2基因。考察突变株的生长和胞内脂肪醛脱氢酶活性变化,并评价CtAld1和CtAld2基因敲除对细胞二元酸合成能力的影响。【结果】分别获得了热带假丝酵母突变株XZX-1(ΔCtAld1/ΔCtAld1)、XZX-2(ΔCtAld2/ΔCtAld2)和XZX-12(ΔCtAld1/ΔCtAld1,ΔCtAld2/ΔCtAld2)。在以十二烷为唯一碳源的培养基中,敲除CtAld2基因显著抑制细胞的生长,胞内脂肪醛脱氢酶活性降低为出发菌株的30%;敲除CtAld1基因尽管会使细胞损失一部分醛脱氢酶活性,但能够一定程度地提升细胞在十二烷中的生长性能。敲除CtAld1或CtAld2会降低菌株二元酸产量,组合敲除CtAld1和CtAld2严重削弱菌株十二碳二元酸的合成能力。【结论】CtAld2对热带假丝酵母细胞的生长和十二碳二元酸的合成具有重要作用,缺失CtAld1或CtAld2基因降低细胞的二元酸合成能力。CtAld1和CtAld2可作为热带假丝酵母ω-氧化途径代谢工程改造的潜在靶点。     

核桃壳提取液用于单针藻Monoraphidium sp.QLZ-3培养产油脂

[目的] 研究核桃壳提取液（walnut shell extracts,WSE）对单针藻Monoraphidium sp.QLZ-3生长和油脂积累的影响。[方法] 向BG-11培养基中添加不同量的WSE（培养基中保留有BG-11中全部营养成分）。[结果] 结果显示,当BG-11培养基中的WSE含量为40%时,单针藻的生物量产率及油脂产率达到（534.70±4.07）mg/（L·d）和（296.35±15.36）mg/（L·d）,相比对照组分别提高了的14.82%和33.50%,蛋白质和碳水化合物含量分别有不同程度的上调和下调。与对照组相比,微藻中谷胱甘肽（glutathione,GSH）和超氧化物歧化酶（superoxide dismutase,SOD）含量与活性均上调。此外,WSE作用下,微藻对多酚的移除达到84.37%,同时上调了核酮糖1,5-二磷酸羧化酶基因（ribulose 1,5-bisphosphate carboxylase/oxygenase,rbcL）和乙酰辅酶A羧化酶（acetyl coenzyme A carboxylase,accD）基因的表达量。[结论] 研究表明,WSE联合BG-11可以提高微藻的生物量产率和油脂产率,降低微藻培养的原料成本,为核桃壳的资源化利用及微藻的工业化生产提供了一定的技术支撑。     

东北地区被子植物新资料

东北地区位于中国东北部,地处欧亚大陆东缘,地域辽阔,环境复杂,植被类型多样,是我国北方植物种类较为丰富、植物区系起源演变发展的重要地区。该研究根据野外实地调查及资料分析,报道了东北地区2种新分布植物,分别是野生堇菜(Viola arvensis)、线叶毛膏菜(Drosera anglica)。野生堇菜为东北地区新归化种,分布于哈尔滨市帽儿山,该种在我国台湾地区有分布,原产于非洲北部、亚洲西南部和欧洲;线叶毛膏菜为中国新记录种,分布于东北长白山区。该属在东北地区还有1种,即圆叶茅膏菜(D.rotundifolia)。两者的主要区别:前者叶为线状匙形,花柱3,每个花柱2分裂至中部;后者叶片近圆形,花柱3,每个花柱深裂至基部。凭证标本保存于东北林业大学植物标本室(NEFI)。这些新资料种的发现,对于丰富东北地区植物种类及对本地区植物多样性的研究具有重要意义。     

Comparative Proteomic Analysis Reveals Nitrogen Fertilizer Increases Spikelet Number per Panicle in Rice by Repressing Protein Degradation and 14-3-3 Proteins

The spikelet number per panicle is established in the early stages of panicle development. Nitrogen fertilizer application before panicle initiation is known to increase spikelet number, which is one of the most important traits in rice productivity determination. However, the basic proteomic mechanism remains poorly understood. The present study shows that nitrogen fertilizer significantly increased spikelet number and grain yield in rice. Proteomic variations were further analyzed in young panicles at the secondary panicle branch initiation and spikelet meristem initiation under nitrogen fertilizer treatment. Proteomic analysis identified 63 proteins with significant differential accumulation in young panicles under nitrogen fertilizer treatment. Proteolysis represents the largest functional category, which suggests that protein degradation is an important pathway in the response to nitrogen fertilizer. Importantly, nitrogen fertilizer significantly reduced 14-3-3 proteins, which interact with key enzymes associated with carbon and nitrogen metabolism, and the rice FT homologue Hd3a. Real-time PCR revealed that Hd3a signaling is also repressed by nitrogen fertilizer in leaves. This study contributes to a better understanding of the regulation of nitrogen fertilizers in the flowering pathway leading to panicle development. The identification of novel genes provides new insight into the profound impacts of nitrogen fertilizer on panicle development in rice.     

重组人S100A6促进人乳腺癌细胞MCF-7的增殖和迁移侵袭并抑制其凋亡

该研究旨在探讨重组人S100A6蛋白对乳腺癌细胞株MCF-7的增殖、凋亡、迁移及侵袭能力的影响。利用原核表达制备重组人S100A6蛋白(GST-hS100A6),SDS-PAGE显示其大小为36 kDa,Western blot显示其可以被S100A6抗体特异识别,BCA法测定1 L菌液共收获约16.7 mg蛋白;将其作用于人乳腺癌细胞MCF-7,MTT显示细胞培养48 h时,浓度为100μg/mL和300μg/mL的GST-hS100A6组的D_(492)值较GST组增加29.1%和84.6%(P<0.05),提示S100A6促进MCF-7细胞增殖;平板克隆形成实验显示GST-hS100A6组的克隆形成率较GST组高38.7%(P<0.05),提示S100A6促进MCF-7的克隆形成;Hoechst染色显示GST-hS100A6组在24 h时细胞凋亡率较GST组减少67.8%(P<0.05),48 h时细胞凋亡率较GST组减少58.4%(P<0.05),提示S100A6抑制MCF-7细胞凋亡;划痕实验显示在24 h时GST-hS100A6组的划痕愈合率为GST组的2.2倍(P<0.05),提示S100A6促...     

Effect of pathogenic cysteine mutations on FGFR3 transmembrane domain dimerization in detergents and lipid bilayers

Mutations in fibroblast growth factor receptors are known as the genetic basis of skeletal growth disorders. The mechanism of pathogenesis, as determined by mutation-induced changes in receptor structure, interactions, and function, is elusive. Here we study three pathogenic Cys mutations, associated with either thanatophoric dysplasia or achondroplasia, in the TM domain of fibroblast growth factor receptors 3 (FGFR3). We characterize the dimerization propensities of the mutant TM domains in detergents and in lipid bilayers, in the presence and absence of reducing agents, and compare them to previous measurements of wild-type. We find that the Cys mutations increase the propensity for dimerization in detergent, with the Cys370 mutant exhibiting the highest propensity for disulfide bond formation, the Cys371 mutant having an intermediate propensity, and Cys375 the lowest. Thus, disulfide bonds readily form in detergents, with efficiency that correlates with the severity of the phenotype. In lipid bilayers, however, the Cys370 mutant, which dimerizes strongly in detergent, behaves as the wild-type, suggesting that Cys370-mediated disulfide bonds do not form between the isolated TM domains in bilayers. Thus, the nature of the hydrophobic environment plays an important role in defining the structure and flexibility of transmembrane dimers. These results and previous findings from cellular studies lead us to propose a conformational flexibility mechanism of receptor stabilization as a basis for disregulated FGFR3 signaling in thanatophoric dysplasia and achondroplasia.