慢生型大豆根瘤菌nfe基因的分子克隆

ｎｆｅＣ基因是从慢生型大豆根瘤菌中克隆到的,与竞争结瘤有关的基因。本研究从慢生型大豆根瘤菌菌株ＧＸ２０１的ｐＬＡＦＲ３为载体的基因文库中,筛选出与ｎｆｅ同源基因克隆。以转座子Ｔｎ５ｇｕｓＡ５诱变获得了ｇｕｓ基因表达的Ｔｎ５ｇｕｓＡ５插入突变质粒。     

甜菜坏死黄脉病毒新疆分离物外壳蛋白基因的序列分析

用根据国外已报道的甜菜坏死黄脉病毒（ＢＮＹＶＶ）的ＲＮＡ２的序列合成的两个引物，通过对ＢＮＹＶＶ新疆分离物的ＲＮＡ逆转录获得了ＢＮＹＶＶ的外壳蛋白基因的ｃＤＮＡ，经ＰＣＲ扩增后用Ｔ４聚合酶补平两端，克隆到ｐＧＥＭ－７Ｚｆ（＋）质粒的ＳｍａＩ位点，转化大肠杆菌ＤＨ５α，经筛选得到正向插入的重组质粒ｐＧＥＢ３。用ＰＣＲ扩增和酶切均得到５９０ｂｐ的ＤＮＡ片段。用ＡＢＩ３７０Ａ型ＤＮＡ全自动序列仪测出该ｃ     

固氮粪产碱菌nifH∷gusA融合基因的构建及在根际联合体系中…

采用ＰＣＲ技术，获得含粪产碱菌ｎｉｆＨ基因启动子的０．６ｋｂＨｉｎｄ－Ⅲ－ＢａｍＨＩ的扩增片段，核苷酸序列分析结果表明，该ＰＣＲ产物的序列与已报道的模板ｎｉｆＨ启动子序列完全一致。通过两轮基因连接、转化和筛选，获得ｎｉｆＨ启动子与ｇｕｓＡ正向连接的融合基因表达载体ｐＴＧＹ７。经三亲结合将ｐＴＧＹ７导入粪产碱菌中，证明该融合基因能在结合子中正常表达。采用融合基因表达的组织化学定位方法，研究粪产碱菌在     

新城疫北京强毒株融合糖蛋白（F）基因的克隆及序列分析

ＮＤＶ北京强毒株Ｆ４８Ｅ９经ＳＰＦ鸡胚增殖,超速离心纯化,异硫氰酸胍法提取病毒ＮＡ后,用ＲＴ－ＰＣＲ扩增,得到其融合糖白基因。将扩增产物与ｐＧＥＭ＾Ｒ－Ｔ载体相连接转化,经过ＡｍｐＩＰＴＧ－Ｘｇａｌ（ＡＩＸ）平板筛选,ＨｉｎｄⅢ酶切及ＰＣＲ鉴定,初步获得了含Ｆ基因的阳性克隆。用渐近法对克隆片段进行全序列分析,证明得到了作长１７４４个核苷酸的ＮＤＶ Ｆ蛋白基因。     

马铃薯Y病毒普通株系外壳蛋白基因的克隆与原核表达载体的构建

本研究报道马铃薯Ｙ病毒普通株系外壳蛋白基因ｃＤＮＡ克隆,全序列分析及其原核表达载体构建的结果。从感染ＰＶＹ的烟草叶片中提取病毒粒体,ＳＤＳ－酚法提取病毒核酸。以所提核酸为模板,用一对ＰＶＰＣＰ基因引物进行ＲＴ－ＰＣＲ,扩增了０．８０ｋｂ的特异性核苷酸片段。该片段大小五国外报道的ＰＶＹ ＣＰ基因一致,将ＰＤＲ产物插入到克隆载体ｐＧＥＭ７Ｚｆ（＋）中转化大肠杆菌ＤＨ５α。     

利用PCR法从文库中快速克隆人促红细胞生成素基因

本文介绍一种利用ＰＣＲ技术从基因文库中快速克隆基因组ＤＮＡ的方法。含有１０７个克隆的人基因文库分成１０份，小量提取ＤＮＡ，利用特异性的寡核苷酸引物检测ＥＰＯ基因的存在与否。经过４轮ＰＣＲ筛选，从阳性管中取１０３个噬菌体进行铺板培养，经原位杂交获得含有ＥＰＯ基因的阳性克隆。阳性克隆的插入片段被亚克隆到质粒上。酶切分析及序列分析的结果均证明我们获得ＥＰＯ基因。ＰＣＲ－筛库法可以快速从文库中获得目的基因     

水稻黄单胞菌水稻变种的rpfA基因的定位和次级克隆

水稻黄单胞菌水稻变种产生两种顺乌头酸酶（ＸｏｏＡｃａｎＡ和ＸｏｏＡｃａｎＢ）,编码ＸｏｏｃａｎＡ的ｒｐｆＡ基因已被克隆在重组质粒ｐＧＸＮ３０００中。本工作通过转座子Ｔｎ５Ｂ２０诱变ｐＧＸＮ３０００,鉴定了ｒｐｆＡ基因的位置及其转录方向,并进一步将含有完整ｒｐｆＡ基因的４．８ｋｂＡｓｐ７１８ＥｃｏＲⅠ片段次级克隆到了多用途载体质粒ｐＩＪ３２００。     

大肠杆菌glgC基因的克隆,序列分析与定点突点

通过ＰＣＲ、从Ｅ．ｃｏｌｉ Ｋ１２ Ｙ１０９０株系中扩增获得ｇｌｇＣ基因,插入ｐＵＣ１９的ＰｓｔＩ和ＳａｃＩ位点之间,得到重组质粒ｐＡＧＰ。对所克隆的ｇｌｇＣ基因进行全序列测定,结果表明,与已发表的序列相比,有７个核苷酸发生了改变,核苷酸顺序的同源性为９９．４％,推导的氨基酸序列的同源性为９９．２％,其中,第２９６位由赖氨酸变为谷氨酸。通过寡核苷酸介导的定点诱变,将第１００７位核苷酸由Ｇ变为Ａ,从     

马铃薯Y病毒小鼠中和抗体轻链基因的克隆及序列分析

从大量繁殖的Ｄ７３杂交瘤细胞中，提取制备其基因ｍＲＮＡ，并以此为模版，经反转录途径获得基因组ｃＤＮＡ，随后将其插入到λｇｔｌｌ中，构建了马铃薯Ｙ病毒小鼠单克隆抗体ｃＤＮＡ基因文库。通过免疫原位杂交，从该基因文库中筛选出含有抗体轻链基因的阳性克隆，进一步将其插入到ｐＧＥＭ－７Ｚｆ（＋）质粒中，经酶谱和ＤＮＡ序列分析确定，完整的轻链基因被获得。该基因含有９５６个核苷酸碱基［不包括Ｐｏｌｙ（Ａ）尾巴］，     

水稻白叶枯病菌dsp基因的克隆,同源性和功能分析

以经转座子Ｔｎ５诱变的水稻白叶枯病菌ｄｓｐ基因突变体ＸｏｏＭ３１０４为材料，构建了ｄｓｐ基因探针质粒ｐＶＩＲ３。采用分子杂交法，从基因文库克隆中筛选出１个ｄｓｐ基因克隆ｐＮＡＸ３１１１，含２２ｋｂ的外源ＤＮＡ插入片段，具有４个ＫｐｎＩ酶切位点，其中３．０，２．０ｋｂ两个片段与探针质粒中Ｔｎ５侧翼的ｄｓｐ基因序列同源。以ｐＮＡＸ３１１１为探针与Ｘｏｏ日本系统、中国系统及菲律宾系统的菌株，细菌性条斑病     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.