种子老化诱导小麦染色体畸变及大麦醇溶蛋白带型频率变化的研究

通过时20份小麦种质发芽率和根尖细胞染色体畸变的测定,结果表明同一品种贮藏于中期库的低发芽率种质,其染色体畸变率明显高于贮藏于长期库的高发芽率种质.从总体上看,种子根尖细胞染色体畸变率与发芽率呈负显著相关,而与贮藏年限无显著相关.但对长期库和中期库的种质分别进行统计分析,种子根尖染色体畸变率与发芽率和贮藏年限均无显著相关.对大麦地方品种"普乃干木"的醇溶蛋白分析表明,该品种有4种biotype,随着发芽率的下降,其群体中的4种bio-type的频率发生了变化,当发芽率从95%降到34%时,其中一种biotype出现了消失,而有一种biotype频率从83%上升至95%,此结果表明,种子生活力下降和不同biotype种子存活能力存在差异,可能导致了异质种质材料遗传选择和漂变的发生.     

尼罗罗非鱼Orexin前体基因的克隆、组织分布及其在摄食调控中的表达

该文采用RT-PCR和cDNA末端快速扩增技术(rapid-amplification of cDNA ends,RACE)的方法,从尼罗罗非鱼(Oreochromis niloticus)下丘脑总RNA中获得了尼罗罗非鱼Orexin前体基因的cDNA全长序列。该cDNA全长648bp,其中开放阅读框的长423bp,编码Orexin前体蛋白为140个氨基酸,包括37个氨基酸的信号肽、43个氨基酸的Orexin-A、28个氨基酸的Orexin-B和末尾32个氨基酸组成的功能不详的多肽。采用Real-time PCR技术对尼罗罗非鱼Orexin前体基因的组织表达模式以及在摄食前后、饥饿和再投喂状态下的表达量变化进行了研究。结果显示,在脑部和外周等18个组织中都检测到了Orexin前体基因的表达,其中在下丘脑中表达量最高;在摄食前后,尼罗罗非鱼Orexin前体基因的表达量显著低于在摄食状态中;饥饿2、4、6和8d后,Orexin前体基因在下丘脑中的表达量与正常投喂组相比均显著升高,饥饿4d再投喂后,表达量又恢复至正常水平。这些结果表明,Orexin在尼罗罗非鱼摄食中可能有着重要的调节作用。     

江西省中华秋沙鸭越冬种群现状调查与胁迫因素分析

于2009年2月对江西省五大水系:赣江、抚河、信江、饶河和修水的越冬中华秋沙鸭种群展开专项调查,分析了江西省越冬中华秋沙鸭种群的数量、性比、空间分布格局、生境特征及其胁迫因素.主要采用样线法在五大水系的主要河道展开同步调查,调查样线总长度400 km.结果发现,江西省越冬中华秋沙鸭有26个生活群255只个体,雌雄性比为119:117,其生活群雌雄性比也多接近1:1.江西省五大水系中,除赣江外,在其他4个水系均发现有中华秋沙鸭越冬群体.除了在曾有中华秋沙鸭越冬记录的婺源、贵溪、弋阳、浮梁、修水发现其越冬群体外,还首次在江西省境内的宜黄、武宁和龙虎山地区发现有较大的中华秋沙鸭越冬群体,而且龙虎山泸溪河段分布有本次调查中个体数量最大的有53只个体的群体.人类采砂活动、水质污染、非法捕鱼和家禽饲养是目前影响该种群生存的主要胁迫因素.     

5种光合细菌种间原生质体融合及优良农用融合子的筛选鉴定

处于对数生长期的光合细菌球形红假单胞菌(Rhodopseudomonassphaeroides)、沼泽红假单胞菌(Rhodopseudomonaspalustris)、嗜酸红假单胞菌(Rhodopseudomdnasacidophila)、深红红螺菌(Rhodospirarubrum)、万尼氏红微菌(Rhodomocrobiumvannielii),经溶菌酶(3mg/L)处理50min后,获得了它们的菌体形成的原生质体,其再生率分别为80%、71%、82%、61%、74%.取等量的亲本菌株在35%的PEG(MW6000)诱导下两两融合5min,共10种组合.其融合率为球×沼2.5×10-4、球×嗜2.1×10-4、球×深2.0×10-4、球×万2.1×10-4、沼×嗜2.8×10-4、沼×深2.4×10-4、沼×万2.6×10-4、嗜×深2.0×10-4、嗜×万2.3×10-4、深×万2.4×10-4.经影印法鉴定:形成的融合子可以分别生长于以相应的有机物为唯一碳源的培养基上,所有融合子体积均相当于两亲本株体积之和,融合子菌落形态特征介于两亲本株之间.从中随机挑选100个融合子,以辣椒苗作为靶标植物,从上述融合子中筛选到了1株具有显著促进作物生长、提高抗病性的融合子.     

基于CSSL的高密度物理图谱定位水稻分蘖角度QTL

对以籼稻9311为遗传背景携带粳稻日本晴基因组的染色体片段置换系（CSSL）的遗传图谱进行分子标记加密,构建了含250个多态标记的高密度物理图谱。以119个CSSLs为材料,P≤0.001为阈值,筛选到分蘖角度与受体亲本9311差异极显著的10个系。结合物理图谱和代换作图方法,共鉴定出5个分蘖角度QTL,其中qTA11的加性效应表现为增效作用,来源于9311的等位基因;其余4个QTL的加性效应为减效作用,均来源于日本晴的等位基因。qTA6-1和qTA6-2分别被定位于第6染色体RM253–RM527之间的3.55Mb区段和RM3139–RM494的1.65Mb区间;qTA9被定位于第9染色体RM257–RM189之间的3.40Mb区段;qTA10被定位在第10染色体RM222–S10-1之间的2.10Mb区段;qTA11被定位于第11染色体RM1761–RM4504之间的3.30Mb区间。以上研究结果为水稻分蘖角度QTL的精细定位和株型育种提供了依据。     

Theoretical Insights into Catalytic Mechanism of Protein Arginine Methyltransferase 1

Protein arginine methyltransferase 1 (PRMT1), the major arginine asymmetric dimethylation enzyme in mammals, is emerging as a potential drug target for cancer and cardiovascular disease. Understanding the catalytic mechanism of PRMT1 will facilitate inhibitor design. However, detailed mechanisms of the methyl transfer process and substrate deprotonation of PRMT1 remain unclear. In this study, we present a theoretical study on PRMT1 catalyzed arginine dimethylation by employing molecular dynamics (MD) simulation and quantum mechanics/molecular mechanics (QM/MM) calculation. Ternary complex models, composed of PRMT1, peptide substrate, and S-adenosyl-methionine (AdoMet) as cofactor, were constructed and verified by 30-ns MD simulation. The snapshots selected from the MD trajectory were applied for the QM/MM calculation. The typical S_N2-favored transition states of the first and second methyl transfers were identified from the potential energy profile. Deprotonation of substrate arginine occurs immediately after methyl transfer, and the carboxylate group of E144 acts as proton acceptor. Furthermore, natural bond orbital analysis and electrostatic potential calculation showed that E144 facilitates the charge redistribution during the reaction and reduces the energy barrier. In this study, we propose the detailed mechanism of PRMT1-catalyzed asymmetric dimethylation, which increases insight on the small-molecule effectors design, and enables further investigations into the physiological function of this family.     

S-腺苷甲硫氨酸的研究现状及应用前景

介绍了S-腺苷甲硫氨酸的制备方法及稳定性研究现状,并对其临床应用及市场前景进行了分析。     

丝状真菌Amorphotheca resinae ZN1的糠醛降解代谢分析

木质纤维素在预处理过程产生的降解产物对后续的酶水解和微生物发酵过程产生了强烈的抑制。因此,这些抑制物的脱除即所谓的"脱毒"步骤是正常进行后续酶解和发酵的前提条件。我们对本实验室筛选的丝状真菌Amorphotheca resinae ZN1的糠醛的代谢路径进行了研究。丝状真菌A.resinae ZN1转化糠醛的降解代谢途径可以简述为:糠醛首先快速地转化为毒性较低的糠醇;在有氧条件下,糠醇又再度生成不致对微生物产生危害的低浓度糠醛,糠醛继续氧化为糠酸。推测糠酸可能继续进入TCA循环,进而完成糠醛的完全降解。研究结果为将来加快丝状真菌A.resinae ZN1生物脱毒速率、改善木质纤维素生物转化的限速步骤提供了重要的实验依据。     

Two mutations in LDLR gene were found in two Chinese families with familial hypercholesterolemia

Familial hypercholesterolemia (FH) (OMIM 143890) is an autosomal dominantly inherited disease mainly caused by mutations of the gene encoding the low density lipoprotein receptor (LDLR) and Apolipoprotein (Apo) B. First the common mutation R3500Q in ApoB gene was determined using PCR/RFLP method. Then the LDLR gene was screened for mutations using Touch-down PCR, SSCP and sequencing techniques. Furthermore, the secondary structure of the LDLR protein was predicted with ANTHEPROT5.0. The R3500Q mutation was absent in these two families. A heterozygous p.W483X mutation of LDLR gene was identified in family A which caused a premature stop codon, while a homozygous mutation p.A627T was found in family B. The predicted secondary structures of the mutant LDLR were altered. We identified two known mutations (p.W483X, p.A627T) of the LDLR gene in two Chinese FH families respectively.     

A novel RGD-toxin protein,Lj-RGD3, from the buccal gland secretion of Lampetra japonica impacts diverse biological activities

RGD (Arg-Gly-Asp) motif toxin proteins from snake venoms, saliva glands secretion of leech or tick have typical characteristics of inhibiting platelet aggregation, angiogenesis, and tumor growth. Here we report cloning and characterization of a novel RGD-toxin protein from the buccal gland of Lampetra japonica. In an attempt to study the activities of anticoagulant in the buccal gland secretion of L. japonica, we established buccal gland cDNA library and identified a gene encoding a predicted protein of 118 amino acids with 3 RGD motifs. The predicted protein was named Lj-RGD3. We generated the cDNA of Lj-RGD3 and obtained the recombinant protein rLj-RGD3. The polyclonal antibodies against rLj-RGD3 recognized the native Lj-RGD3 protein in buccal gland secretion in Western blot analyses. The biological function studies reveal that rLj-RGD3 inhibited human platelet aggregation in a dose-dependent manner with IC₅₀ value at 5.277 μM. In addition, rLj-RGD3 repressed bFGF-induced angiogenesis in the chick chorioallantoic membrane model. rLj-RGD3 also inhibited the adhesion of ECV304 cells to vitronectin. Furthermore, rLj-RGD3 induced apoptosis and significantly inhibited proliferation, migration, and invasion evoked by bFGF in ECV304 cells. Taken together, these results suggested that rLj-RGD3 is a novel RGD-toxin protein possessing typical functions of the RGD-toxin protein.