‘凤丹’牡丹PoKAS基因的克隆及表达分析

为探究‘凤丹’牡丹(Paeonia ostii‘Feng Dan’)PoKAS基因在脂肪酸合成中的功能,从转录组数据中获得3个PoKAS基因,克隆基因全长并进行生物信息学分析,通过qRT-PCR检测它们在牡丹落花后第23、45、75、100和125天时的表达。结果显示：(1)克隆得到的3个基因序列全长分别为1 401、1 692和1 215 bp,分别编码466、563和404 aa;保守结构域分析发现,它们都含有KAS保守结构域,属于cond-enzymes超蛋白家族。(2)系统进化树将三者分为三大类,表明其在进化上相对独立,分别命名为PoKASⅠ、PoKASⅡ和PoKASⅢ(GenBank登录号分别为OP056413、OP056412和OP056414)。(3)qRT-PCR分析发现,在牡丹落花后种子发育的5个时期中,PoKASⅠ和PoKASⅡ基因在落花后75 d和45 d时的表达量分别显著高于其他发育时期;PoKASⅢ基因在落花后45～125 d时的表达量均显著高于落花后23 d,说明PoKASⅢ基因在牡丹种子脂肪酸合成的整个过程中发挥着重要作用,而PoKASⅡ基因主要在种子油脂...     

Co‐limitation of photosynthetic capacity by nitrogen and phosphorus in West Africa woodlands

Photosynthetic leaf traits were determined for savanna and forest ecosystems in West Africa, spanning a large range in precipitation. Standardized major axis fits revealed important differences between our data and reported global relationships. Especially for sites in the drier areas, plants showed higher photosynthetic rates for a given N or P when compared with relationships from the global data set. The best multiple regression for the pooled data set estimated V_cmax and J_max from N_DW and S. However, the best regression for different vegetation types varied, suggesting that the scaling of photosynthesis with leaf traits changed with vegetation types. A new model is presented representing independent constraints by N and P on photosynthesis, which can be evaluated with or without interactions with S. It assumes that limitation of photosynthesis will result from the least abundant nutrient, thereby being less sensitive to the allocation of the non‐limiting nutrient to non‐photosynthetic pools. The model predicts an optimum proportionality for N and P, which is distinct for V_cmax and J_max and inversely proportional to S. Initial tests showed the model to predict V_cmax and J_max successfully for other tropical forests characterized by a range of different foliar N and P concentrations.     

A mimotope of Pre-S_2 region of surface antigen of viral hepatitis B screened by phage display

INTRODUCTIONHepatitis B virus (HBV) infection is the mostcommon viral infection in humans especially inChina and East Asia. At present, the most effi-cient method to control the disease is vaccinationof new-borns. Both blood derived vaccine and re-combinant vaccine are hepatitis B surface alltigen(HBsAg)-based and useful in the prevention of thedisease[1-3]. HBsAg could evoke protective humoralimmune response in vivo, but the immune memoryonly last for 5 years or so[3, 4]. How to des…     

Lesliea,a Newly Recorded Genus of Orchidaceae from China

Lesliea, a newly recorded genus of Orcihdaceae from Yunnan, China, is reported. This is monotypic genus, differing from its relatives by having saccate spur, long and bifid rostellum and the obconical stipe.     

传统农业生态系统中桤木改良土壤效应研究综述

桤木(Alnus nepalensis)是一种重要的非豆科固氮植物,广泛分布于喜马拉雅山脉东部地区。在东南亚地区的传统农业生态系统中,多用桤木作为休耕树种,或将其与农作物间作。桤木根瘤固氮量随季节和年龄而变化,在桤木-小豆蔻(Elettaria cardamomum)系统中15年达到高峰(155 kg·hm^-2);桤木通过共生固氮对系统产生的氮增加量在纯桤木林中7年达到高峰(117 kg·hm^-2)。桤木与农作物间作可显著提高农作物的产量,桤木-小豆蔻立地上小豆蔻的经济产量是在森林-小豆蔻立地上的2.2倍。桤木休闲地的休闲效果明显好于自然休闲地,其地上部分生物量在休闲6年后是自然休闲地的4倍,N蓄积量是自然休闲地的3倍,P、K蓄积量是自然休闲地的2倍。桤木根系特征似乎最适合混农林系统,其细根生物量(FRB)集中于土壤剖面上层10 cm范围内,在此范围内,FRB在“树+农作物”间作条件下比在“只有树”条件下高5%;在两种立地条件下,60%以上的细根都分布于树干周围0.5 m内,大部分木质根(直径>0.5 mm)都分布于土壤上层0~10 cm处,长度都不超过1 m。桤木可加速系统的养分循环。桤木凋落物降解速率比非固氮植物快,并且与其它植物凋落物混合后的降解速率与自身凋落物降解速率一样快。在传统刀耕火种系统中,用桤木替代自然林休闲在3~6年内即可恢复土壤肥力,改善土壤理化性质,显著缩短休闲周期。该文综述了近30年来桤木在传统农业生态系统中改良土壤效应的研究成果,以提高人们对桤木的生态作用的重视程度,使人们更好地将桤木利用到农业生态系统中,达到发展山区农业和保护生态环境双赢的目的。     

基因修饰的肝细胞脾内移植后体内分布和基因表达的实验研究

为探讨基因修饰的肝细胞经脾内移植途径介导肝脏基因治疗的可行性和有效性,体外用NeoR基因或IL-2基因修饰小鼠正常胚胎肝细胞BNL CL.2,经脾内移植至正常同系小鼠体内(2×10⁶/只),观察NeoR和IL-2基因在不同脏器的表达.结果发现脾内移植NeoR基因修饰的肝细胞后24h,即可通过RT-PCR在肝脏中检测出NeoR基因mRNA的表达,持续表达11周以上;此外,NeoR基因在脾脏中短暂表达(24h至1周),在肺组织中也有一过性表达(48～96h).脾内移植IL-2基因修饰的肝细胞后,肝脏中可检测到稳定表达的IL-2mRNA(24h至11周),外周血中维持一定水平(5～40pg/mL)的IL-2,能增强肝脏Kupffer细胞Ia抗原的表达及脾细胞的NK杀伤活性.提示基因修饰的肝细胞脾内移植后能定向分布至肝脏,并同化入肝组织中长期存活,有效地表达外源基因,可成为肝脏靶向性基因治疗的可行途径.     

Multiple origins of Locusta migratoria (Orthoptera: Acrididae) in the Japanese Archipelago and the presence of two major clades in the world: evidence from a molecular approach

Phylogenetic relationships among migratory locust (Locusta migratoria) populations in different climatic regions were analysed by sequencing four mitochondrial DNA regions, with special reference to the origin of Japanese populations. The populations are clearly separated into two clades: one consists of individuals from temperate and cold‐temperate areas of Japan and the Chinese continent, and the other comprises those from subtropical islands of Japan, Hainan Island in China, Timol Leste, Australia, Ethiopia, France, and some individuals from Tsushima Island and Honshu of Japan. The divergence time between the two clades is estimated to be 0.86–1.89 Mya. The phylogenetic analysis revealed that Japanese L. migratoria populations were composed of individuals of six different origins: (1) Hokkaido populations possibly from the Russian continent; (2) Honshu–Kyushu populations from the Chinese continent; (3) Southwest Island populations from Hainan Island or adjacent areas; (4) Ogasawara populations that might have originated from Micronesia; (5) part of the Tsushima population that originated from somewhere in the Asian tropics; and (6) a possible relict population of ancient southern haplotypes that exists in western areas of northern Honshu. The Tsugaru Straits and Tokara Straits have acted as effective geographical barriers, as in other organisms, isolating locust populations for a few thousand years. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 570–581.     

父母MTHFR基因型对后代发生神经管畸形的影响

本研究旨在探讨父母双方MTHFR基因型与其后代发生神经管畸形风险性的关 系。采用成组匹配的病例对照研究方案,用纸片法采集病例和对照外周血标本,用PCR-RFLP方法确定基因型(C677T)。结果显示,分别比较两组父亲或母亲基因型频率时,差别不显著;将父母基因型联合起来分析则发现,病例组父母等位突变基因频率(T)高于对照组父母,提示后代是纯合突变( TT)概率越大,发生NTD的风险性也越大。结论是,父母双方的基因型对后代发生NTD的风险性有同等重要的作用,父母双方传递给胎儿的一对突变等位基因(T/T)是NTD发生的风险因素之一。 Abstract:The effect of parental MTHFR genotypes on fetal phenotype of NTD is studied.It was designed as group matched case-control study.Venous blood cases and controls were collected by dry blood spots.Genotype(C677T)of each sample was decided by PCR-RFLP method.When the genotypes of father and mother are compared separately,no significant difference is discovered between cases and controls.On the other hand,when the mutant allele frequency(T)is computed for father and mother together,it is significantly higher in cases than in controls.Higher probabilities of the offspring being homozygotes(TT),higher the risk for NTD occurrence has been observed.It is concluded that genotypes of MTHFR for both father and mother have the same impact on NTD occurrence of their offspring.It is the pair of mutant allele(T/T)which transmitted to the baby from its parents that increases the risk.     

母体遗传效应对绒山羊生产性状遗传参数估计的影响

利用非求导约束最大似然法(DF-REML), 比较了内蒙古白绒山羊在两种不同动物模型下估计遗传参数的差异, 两种模型的区别在于是否考虑母体遗传效应。对两种模型的差异用似然比进行检验。结果表明, 母体遗传效应对于体重和绒厚影响极显著(P<0.01), 对于抓绒量、毛长、绒长度以及绒细度影响不显著(P>0.05)。