应用PCR/RFLP技术对广西禽白血病病毒的检测与分型研究

对2000～2003年间从广西的南宁、玉林、桂林、钦州、柳州、梧州等地采集的有肿瘤/可疑肿瘤的250份鸡病例进行肿瘤病的检测.结果发现,外源性禽白血病阳性的有32份,阳性率为12.8%.其中,同时为马立克氏病阳性的有30份,两者共感染率高达93.75%(30/32);根据禽白血病病毒囊膜糖蛋白gp85基因的限制性片段长度多态性分析,对其中20份外源性禽白血病病毒进行分型鉴定,结果证实全部属于A亚群.     

A Classification of 45 Maize Inbred Lines Used in China with RFLP Markers

The classification of heterotic groups is essential to maize breeding because knowledge of heterotic groups could be interest to both the combination of outstanding hybrids and the improvement of elite inbred lines. RFLP has provided a powerful tool to assign maize inbred lines into heterotic groups. In this investigation, 45 inbred lines, used widely in south and southwest China, were chosen for RFLP analysis,among which 4 lines came from American, representing different heterotic groups in U.S. corn belt. 54 RFLP core markers covering 10 chromosomes of maize were used. A total DNA of each sample was digested with EcoR I, BamH Ⅰ and Hind Ⅲ . The procedure of RFLP was employed as described by a manual from maize RFLP lab at University of Missouri, Columbia. A total of 860 bands were detected among 45 inbred lines based on RFLP analysis, which were involved in 212 loci. Alleles at each locus ranged from 2 to 9 with an average of 4.06. In total, The 45 inbred lines were classified into 6 heterotic groups according to RFLP data with Ward‘s method. 3 heterotic groups, including Mo17, B73 and Oh43 respectively, seemed to be the same to U. S. heterotic groups. 21 inbred lines, most of which derived from Chinese local germplasm, were classified together into two heterotic groups, indicating domistic germplasm was different from U. S.germplasm at the molecular level and played an important role in maize hybrid production in China. Two inbred lines from tropic germplasm were assigned in the same group. These results provided useful information for our understanding maize heterotic groups and heterotic patterns in China.     

苏云金杆菌新菌株WB9 cry1基因型的PCR-RFLP分析

利用 PCR- RFLP技术对 Bt新菌株 WB9的 cry1基因型进行分析 ,结果表明该菌株含有 cry1Aa、cry1Ab、cry1Cb、cry1Fa和 cry1Ga 5种 cry1基因型 ,且 cry1Ab的酶切产物不同于正常的 cry1Ab.采用特异引物对 G1/ G2扩增 ,也证明 WB9含有 cry1Ab基因 .在此基础上 ,再利用引物对 G1/ K3un2进行扩增 ,其产物经回收纯化后用 Eco R / Xba 双酶切分析 ,结果也表明 WB9所含的 cry1Ab与众不同 ,无大片段出现且有一条 4 0 0 - 5 0 0 bp的特异片段     

甘蓝型油菜NCa胞质不育系的不育胞质类型鉴定

用恢保关系测定法和线粒体DNA RFLP分析法对甘蓝型油菜细胞质雄性不育系NCa的不育胞质类型进行了鉴定.以104个来源不同的甘蓝型油菜品种为测交种,分别与NCa、pol、nap、ogura等4种不育系进行恢保关系测定.其中,77%(80个)的测交种能恢复NCa不育系的育性,且主要(80%)分布于国内和欧洲甘蓝型油菜品种中,仅有8个材料可以保持其不育性;80%(83个)的测交种可以保持pol不育系的不育性、95%(99个)的测交种可以恢复nap不育系的育性;而对Ogura不育系,仅有1个材料可以恢复育性,其余103个测交种都保持其不育性.NCa不育系与nap、pol、ogura不育系在104个测交种间表现不同育性的组合分别占25%、89%、92%.NCa不育系与nap、pol、ogura不育系具有明显不同的恢保关系.用RFLP方法初步分析了NCa、pol、nap、ogura等4种不育系的线粒体DNA多态性,发现它们之间具有明显的差异,从而在分子水平上证明NCa不育系是不同于nap、pol、ogura不育系的新型不育胞质类型.     

Bacterial community in plant residues in a Japanese paddy field estimated by RFLP and DGGE analyses

Plant residues (PRs) are “hot spots” of microbial activities in soil. PRs with the size more than 0.5 mm were collected from a Japanese paddy field during rice cultivation period (from May to September) and fractionated into four categories by size (>4, 2-4, 1-2, and 0.5-1 mm) using sieves. Restriction fragment length polymorphism (RFLP) and denaturing gradient gel electrophoresis (DGGE) patterns were compared among the fractions after DNA extraction from the PRs and PCR amplification. The total amount of PRs with the size over 0.5 mm decreased in the field with the first-order kinetics (r²=0.810, p<0.01) with time from rice transplanting to harvest. RFLP analysis showed that the bacterial community structure in PRs with the 0.5-2 mm fraction was different from that in PRs with the >2 mm fraction and the latter community structure changed after the midseason drainage. In contrast, the DGGE patterns of the bacterial community in the PRs indicated the succession from June to September during rice cultivation forming three major groups irrespective of the fraction size. Sequence analysis of DGGE bands showed that Firmicutes (clostridia), α-, γ-, δ-Proteobacteria (myxobacteria), Nitrospira, Acidobacteria, Bacteroidetes, Verrucomicrobia and Spirochaetes were predominant members in the PRs irrespective of fraction size.     

中国栽培稻及其近缘野生种叶绿体DNA的限制性片段长度多态性分析

 对中国现存的七省（区）的17份中国普通野生稻（其中广西普通野生稻6份，东乡野生稻5份，广东、湖南各2份，福建及云南景洪普通野生稻各1份）及28份栽培稻地方品种的叶绿体DNA进行了限制性内切酶酶切分析。28份中国栽培稻被分成三类，C1、C2和C3。其中C2叶绿体基因组类型仅有1份材料，为一个籼稻品种。两个主要类型C1和C3分别对应于粳型和籼型，说明中国栽培稻在叶绿体基因组存在籼、粳分化。17份中国普通野生稻的叶绿体DNA用同样3种内切酶酶切，共产生两种类型。它们分别与栽培稻中的C1和C3相同，其中C1类型占主要，为94.1％（16／17），具C3型叶绿体基因组的野生稻为１份广西材料。此外没有检测到新的类型。这说明在中国普通野生稻中也存在对应于栽培稻籼型和粳型两种不同的叶绿体基因组类型，而且是以对应于粳型的C1型叶绿体基因组类型材料为主。从大多数中国普通野生稻具有与粳型栽培稻相同的叶绿体基因组类型，可以推测粳稻起源于中国的可能性很大。     

Community structure of bacteria and fungi responsible for rice straw decomposition in a paddy field estimated by PCR-RFLP analysis

Rice straw including leaf sheaths and blades put in nylon mesh bags was placed in the plow layer of a Japanese paddy field after harvest under upland conditions and after transplanting of rice seedlings under flooded conditions. In addition, rice straw that was decomposed under the upland conditions during the off-crop season in winter was placed again in soil at the time of transplanting. The materials were collected periodically to analyze the community structure of the bacteria and fungi responsible for rice straw decomposition by PCR-RFLP analysis. The PCR products with 27f and 1492r primers designed for bacterial 16S rDNA and with EF3 and EF4 primers designed for fungal 18S rDNA were digested with four restriction endonucleases (Hinf I, Sau3A I, Hae III, EeoR I). Bacterial communities in the decomposing rice straw were different from each other between upland and flooded conditions, between leaf sheaths and blades, and between straw samples with and without decomposition under upland conditions during the off-crop season. Fungal communities in the decomposing rice straw were also different between the leaf sheaths and blades under upland soil conditions. Score plots of bacterial and fungal communities in the principal component analysis were separated from the plot of the straw materials along with the duration of the placement, indicating the succession of bacterial and fungal communities in decomposing rice straw with time.     

Glucose metabolism in detached leaves of tomato plants grown with ammonium and nitrate as nitrogen sources

The metabolism of exogenous glucose-¹⁴C in the light and the dark was studied in the detached leaves of tomato plants grown with ammonium nitrogen and nitrate nitrogen. In the light, ¹⁴CO₂, release and incorporation of glucose into insoluble materials were hardly affected at all by the nitrogen sources. Among the soluble labelled amino acids, serine had the greatest amount of label in the ammonium-plants while aspartate had the greatest amount in the nitrate-plants. This aspartate was synthesized from C₃-compounds by carboxylation. During dark-light transition, the change in the composition of soluble amino acids was more rapid in the ammonium-plants than in the nitrate-plants. In the dark, ¹⁴CO₂-release, which was ten times as much as in the light, was larger in the ammonium-plants than in the nitrate-plants; but the synthesis of high molecular compounds from glucose in the ammonium-plants was about half that in the nitrate-plants. So, it is considered that respiration operates sufficiently in the ammonium-plants. The effects of DCMU and a 100% O₂ atmosphere on glucose metabolism in both groups of plants were studied and the respiration of leaves in the light was discussed.     

SNP-based genotyping and whole-genome sequencing reveal previously unknown genetic diversity in Xanthomonas vasicola pv. musacearum,causal agent of banana xanthomonas wilt,in its presumed Ethiopian origin

For decades, Xanthomonas vasicola pv. musacearum (Xvm) has been an economically important bacterial pathogen on enset in Ethiopia. Since 2001, Xvm has also been responsible for significant losses to banana crops in several East and Central African countries, with devastating consequences for smallholder farmers. Understanding the genetic diversity within Xvm populations is essential for the smart design of transnationally reasoned, durable, and effective management practices. Previous studies have revealed limited genetic diversity in Xvm, with East African isolates from banana each falling into one of two closely related clades previously designated as sublineages SL 1 and SL 2, the former of which had also been detected on banana and enset in Ethiopia. Given the presumed origin of Xvm in Ethiopia, we hypothesized that both clades might be found in that country, along with additional genotypes not seen in Central and East African bananas. Genotyping of 97 isolates and whole-genome sequencing of 15 isolates revealed not only the presence of SL 2 in Ethiopia, but additional diversity beyond SL 1 and SL 2 in four new clades. Moreover, SL 2 was detected in the Democratic Republic of Congo, where previously SL 1 was the only clade reported. These results demonstrate a greater range of genetic diversity among Xvm isolates than previously reported, especially in Ethiopia, and further support the hypothesis that the East/Central Africa xanthomonas wilt epidemic has been caused by a restricted set of genotypes drawn from a highly diverse pathogen pool in Ethiopia.     

湖北淤泥湖团头舫mtDNA限制性片段长度多态性的研究

用ＢａｍＨＩ、ＢｇｌＩ、ＣｌａＩ、ＥｃｏＲＩ、ＨｉｎｄⅢ、ＫｐｎＩ、ＰｓｔＩ，ＰｖｕⅡＳａｃⅡ、ＳａｃＩ、ＳｃａＩ、ＸｂａＩ，ＸｂａＩ和ＸｈｏＩ十四种限制性内切酶对来源于湖北淤泥湖的团头舫进行线粒体ＤＮＡ限制性片估长度多态性研究。初步表明ＤＮＡ上切点呈现不同程度的多态性。共检测到六种母集集团。发现一尾团头舫ｍｔＤＮＡ分子大小比普通型鱼ｍｔＤＮＡ小约０．７０ｋｂ。呈现出ｍｔＤＮＡ发子大小多态现象。