Evaluation of Galium species and populations using morphological characters and molecular markers

Three Galium species are believed to be present across western Canada: Galium aparine, Galium spurium and Galium boreale. Galium spurium and G. aparine are very difficult to distinguish morphologically, which is problematic for crop consultants and weed surveyors, and could have implications for control measures. Molecular techniques could potentially make identification easier and more rapid than using chromosome counts, as is currently done. The objective of this study was to identify morphological traits and/or genetic polymorphisms capable of species differentiation. To this end, Galium seed of unknown speciation were collected from nine field populations across western Canada and, along with two reference samples of G. spurium and G. aparine, were characterised for both morphological traits and their ribosomal ITS1‐5.8S‐ITS2 genomic sequence. In addition, single nucleotide polymorphism variation within the highly conserved 5.8S ribosomal RNA gene was identified that could consistently differentiate Galium species. Sequence analysis of the ITS1‐5.8S‐ITS2 region of field collections from western Canada indicated that all samples were G. spurium and all were highly related to each other. These results were supported by a distinct lack of variation in morphological traits, as nearly all plant traits measured did not differ between populations. This suggests that all sampled populations, and perhaps most of the Galium populations across western Canada, are derived from a single species, G. spurium.     

鸡肉汤中滋味呈味前体物质的提取方法研究

以120日龄的武隆黑鸡为研究对象,以提取液总氮含量、游离氨基酸含量、无机离子含量为评价指标,评价热水抽提法、冷水抽提法、冷水-乙醇抽提法等3种方法对滋味物质的提取效果。结果表明,就总氮抽提率而言,冷水抽提法的总氮抽提率为17.83%,冷水-乙醇抽提法的抽提率为10.31%,而热水抽提法提取率为9.06%。就抽提液游离氨基酸的抽提效果而言,热水抽提法效果最好,抽提液游离氨基酸总含量为309.15 mg/L;冷水-乙醇抽提法的效果次之,抽提液游离氨基酸总含量为282.06 mg/L;冷水抽提法的抽提效果最差,抽提液游离氨基酸总含量为258.02 mg/L。就无机离子抽提效果而言,热水抽提的效果最好,抽提液无机离子总含量为998.54 mg/L;冷水抽提法次之,抽提液无机离子总含量为752.69 mg/L;冷水-乙醇抽提法的效果最差为474.08 mg/L。综上所述,热水抽提法可以作为滋味呈味物质提取的有效方法。     

基于全基因组重测序的中国猕猴桃溃疡病菌遗传多样性分析

 由Pseudomonas syringae pv. actinidiae (Psa)引起的猕猴桃细菌性溃疡病是为害猕猴桃的一种毁灭性病害,1996年被列为我国森林植物检疫对象。本研究对来源于我国7个受溃疡病为害最严重地区的21个Psa菌株进行重测序分析,通过主成分分析和系统发育学分析将21个菌株分为三大类群;固定系数分析结果显示所有群体的F_ST值均小于0.05;核苷酸多态性分析结果显示所有菌株的Θπ值仅为3.74×10^-6,且各群体间的差异不明显。这些结果表明Psa在我国的遗传多样性处于低水平状态。基因流(Nm)分析结果显示不同群体之间的Nm值均大于4,表明各群体病原菌之间存在较大的基因交流;Tajima′s D中性检验结果显示所有群体的Tajima′s D值均大于0,暗示各群体都经历平衡选择;Ka/Ks分析结果显示Psa的大部分基因都受到纯化选择,仅有极少数的基因受到正选择。本研究揭示了中国7个受溃疡病危害最严重地区Psa的遗传多样性,并且获得大量基因组数据,可为病害防治、病原菌耐药性以及抗病植株的选育提供理论依据。     

三类分子探针对常见赤潮生物的检测

集中使用寡核苷酸、肽核酸和细胞凝素3类探针对来自东海和厦门海域的现场赤潮样品进行了检测,尝试鉴定识别自然水样中有害的赤潮原因种塔玛亚历山大藻,微小原甲藻和纤小裸甲藻,建立和优化了这些探针的检测方法和样品处理程序.结果表明,在东海和厦门海域的赤潮样品中均成功地检出了塔玛亚历山大藻的分布情况,各探针的检测效率为DBA>Tama28S>Tama5S;在东海和厦门海域的赤潮样品中,也成功地检测出了微小原甲藻,各探针的检测效率为:ConA>PM18S02>PM28S02;在厦门海域的赤潮水样中检出了纤小裸甲藻,各探针的检测效率为:WGA>PNATP28S01>TP18S02>TP28S01.各探针检测结果与相关文献的报道吻合较好.比较这3类探针的特异性,其中以PNA探针为最好,其次为DNA;lectin探针的特异性相对较弱.     

A preliminary identification of genomic loci for body colour variation in the sea cucumber Apostichopus japonicus

The sea cucumber Apostichopus japonicus is one of the most economically important aquaculture species in China, which shows a distinct characteristic of body colour variation. A number of purple variants were obtained in the coast of China, which shows great potential to develop a niche market. In the present study, to understand the genetic basis of green‐purple colour variation, a genome‐wide association study based on the 2b‐RAD sequencing was conducted. As a result, 8,795 genome‐wide single nucleotide polymorphism (SNP) markers were obtained and then applied to the association analysis. Ten most associated SNP loci with p‐value <1.0 × 10^–8 were obtained, and they were assigned to 4 chromosomes (chr17, chr21, chr15 and chr05). In genomic regions neighbouring to those SNPs, 33 candidate genes with annotation were obtained and the endothelin‐converting enzyme‐1, which was reported to be involved in pigmentation variation, was identified. To our knowledge, this is the first report of the genetic locus for body colour variation in this species. These findings will be useful for the fine mapping of the determining gene for body colour variation of A. japonicus.     

改善夏秋绿茶滋味品质研究现状

本文在论述绿茶滋味构成和环境条件对滋味影响的基础上,总结了目前改善夏秋绿茶滋味品质的技术措施,并建议重点发展茶林间种、茶果间种、茶粮间作等模式的复合生态茶园,推广蒸汽杀青和微波干燥等技术措施,以进一步改善夏秋季绿茶滋味品质。     

Characterization and partial sequence of a new furovirus of wheat in China

A soil-borne wheat virus causing severe mosaic and stunting symptoms on wheat in China has been characterized. It had been considered to be soil-borne wheat mosaic virus (SBWMV) because of its rod-shaped virions and similarities to epidemiology and host range. In this study, the virions purified from infected wheat tissue were approximately 20 nm in diameter and of two lengths (140–160 nm and 280–300 nm), with a coat protein of 19 kDa and two RNA components of approximately 7 and 3.5 kb. A rabbit antiserum was produced against the virus and a serological relationship to SBWMV from the USA (Oklahoma) was demonstrated. However, the coat protein was not recognized by most monoclonal antibodies against Oklahoma SBWMV in either ELISA, ISEM or Western blot analysis, indicating epitope differences. In RT-PCR experiments the viral nucleotide sequences were significantly different from those of SBWMV, and this was confirmed by partial sequencing of the cloned PCR fragments generated from RNA1 ( c . 1100 nt) and RNA2 ( c . 1400 nt), which showed homologies of about 79 and 63%, respectively, to corresponding regions of SBWMV. Because of these significant differences in serology and nucleotide sequence it is suggested that it is a new furovirus for which the name Chinese wheat mosaic virus (CWMV) is proposed.     

规范化食品品评试验的运作与设计

本文针对国内某些品评试验不尽规范的现状,阐述了较为规范的操作方法,因此为从定性及定量两方面进行科学可靠的食品感官评价试验,奠定了一定基础     

抗A型产气荚膜梭菌α毒素单链抗体的基因克隆及核苷酸序列分析

应用 RT-PCR技术 ,从分泌具有中和活性的抗 A型产气荚膜梭菌α毒素单克隆抗体 ( Mc Ab)的杂交瘤细胞 2 E3中 ,扩增出抗体 VH 和 VL 基因 ,用 linker( Gly4Ser) 3基因 ,将 VH 和 VL 基因连接成 Sc Fv基因 ,并将其克隆至 p GEM-T载体中。经核苷酸序列分析证实 ,VH、VL 基因和 linker基因拼接正确 ,基因全长为 72 6bp。经计算机分析 ,VH 和 VL 基因均为新发现的基因序列 ,符合功能性重排的鼠抗体可变区基因特征。VH 和VL 基因分别属于鼠免疫球蛋白重链 ( B)和轻链κ 家族     

霍乱毒素B亚单位基因的克隆及其核苷酸序列分析

利用 PCR技术从含有霍乱毒素 B亚单位 ( CTB)基因的质粒 p UCT1中扩增出不包括信号肽的 3 0 9bp的 CTB全基因 ,并通过点突变技术消除了 CTB阅读框内的终止密码子 ( TAA→GAA) ,以便于在 CTB基因的下游融合其他的外源基因。用限制性内切酶 Bam H 和 Eco R 对 PCR产物进行双酶切 ,以 T4DNA连接酶将其定向连接于经同样酶切处理的质粒 p ET-2 8b( )的多克隆位点上 ,构建成重组质粒 p ECTB,转化至BL2 1 ( DE3 )中。经 Bam H 和 Eco R 双酶切分析和 PCR扩增检测 ,证明重组质粒 p ECTB中含有 CTB基因。核苷酸序列分析表明 ,克隆的 CTB基因在重组质粒中的连接向位和阅读框架是正确的