中国禽(番鸭)呼肠孤病毒YB株S4基因序列分析

应用非免疫番鸭胚增殖中国禽(番鸭)呼肠孤病毒YB分离株,用LSTRIAZOL提取病毒RNA,反转录-聚合酶链反应(RT-PCR)扩增中国禽(番鸭)呼肠孤病毒YB分离株S4基因节段cDNA.将S4cDNA克隆到PMDl8-T载体上,并进行了鉴定和核苷酸序列测定.序列分析结果,克隆的S4cDNA共1 124bp,包括非编码区和完整的阅读框架.分子进化系统分析表明该毒株与禽呼肠孤病毒(鸡呼肠孤病毒)的亲缘关系较远,DRV-YB与DRV-89330同缘率为93.3%.     

Y58S系列组合产量、品质及抗性的综合表现

为选育不育起点温度低、配合力强、米质优的实用型两系不育系,以近年来新育成的22个Y58S组合为对象,对其产量、品质及病虫抗性进行研究。结果表明：平均产量为8978.7 kg/hm²,所有品质指标均达到《优质稻谷》3级标准的组合占40.9%,感稻瘟病和褐飞虱。因此,Y58S系列组合产量水平较高,稻米品质较优,主要病虫抗性相对较差。     

猪场副猪嗜血杆菌的分离鉴定及药敏试验

为查明贵阳市花溪区麦坪镇某猪场仔猪发生呼吸道疾病的病因,对送检的2头病猪采集病料进行细菌分离培养、染色镜检、生化试验、PCR扩增及测序、药敏试验。结果:从病料样本中分离得到1株细菌,根据形态学和生化试验初步鉴定为副猪嗜血杆菌;应用细菌16S rRNA序列分析技术从分子水平对分离细菌进行分型鉴定,运用DNAStar软件与不同血清型副猪嗜血杆菌基因序列进行比对,发现分离菌与不同血清型副猪嗜血杆菌菌株16S rRNA序列同源且相似性为97.4%～100%,其中与血清5型相似性最高;系统进化分析显示,分离菌株与血清5型副猪嗜血杆菌进化关系最近;分离菌株对利福平、头孢氨苄、阿米卡星、环丙沙星、万古霉素敏感。结论:综合分离细菌传统鉴定方法和分子生物学鉴定方法的实验结果,确定分离菌株属于血清5型副猪嗜血杆菌。     

Consumer willingness to pay price premiums for environmentally certified wood products in the U.S.

Since its inception nearly 15 years ago, environmental certification has become an important issue in the wood products industry. One research question that has been examined is the potential willingness for supply chain participants to pay a premium for certified products or raw materials to offset certification costs. This study examines stated willingness to pay for four wood products from the perspective of U.S. consumers. Data was collected in 1995 and 2005 from the population of U.S. residential consumers to detect changes in willingness to pay for certified wood products along time and increase the statistical strength of the model. Results of an ordered probit model suggest that higher probabilities of paying a premium are associated to consumers who seek out certified products and who believe certification can lessen environmental impacts such as tropical deforestation. There is also a strong relationship between respondent income and willingness-to-pay. Despite the current industry structure in the U.S. that has adopted a mass-certification strategy that does not place price premiums on certified products, results suggest that such premiums may exist for imported certified tropical wood products. Analysis of marginal effects suggests consumers' willingness to pay a 10% premium for three of the four certified items studied. Niche markets may potentially be exploited in the U.S. and price premiums captured by wood products manufacturers in tropical regions and/or American importers.     

西北地区马铃薯疮痂病病原菌鉴定及其生物学特性

为明确西北地区马铃薯疮痂病病原菌的种类和生物学特性,分别采用常规组织分离法和土壤混悬液分离法从宁夏、陕西和甘肃3个省区采集的29份疮痂病发病薯块和8份发病地块土壤中进行病原菌分离,并利用形态特征、生理生化特性和16S rDNA序列分析对病原菌进行鉴定。结果表明,从发病薯块和发病土壤中共分离到50株链霉菌Streptomyces spp.,通过回接法验证获得6株马铃薯疮痂病致病菌株。6株致病菌株的培养特性和形态特征差别较大;其中菌株G4-1、G9和SYN13不能以果糖和木糖为单一碳源,菌株SYNT3不能以棉子糖为单一碳源;除菌株NLG4-1外,其余5株菌株均能在络氨酸琼脂培养基上产生黑色素。经16S rDNA序列分析,菌株G4-1、G9与疮痂病链霉菌S. scabiei的相似率分别达99.47%和99.34%,菌株NLG4-1、SYNT3与S. enissocaesilis的相似率分别达97.90%和98.18%,菌株GBH2与加利利链霉菌S. galilaeus的相似率达99.93%,菌株SYN13与S. turgidiscabies的相似率达97.56%,表明西北地区马铃薯疮痂病病原菌至少存在4个种。     

一种新发生的玉米细菌性叶腐病病原菌分离鉴定

为了明确一种引起玉米叶片腐烂的细菌性病害的病原菌种类, 于2021年7月在甘肃省景泰县条山农场玉米种植区采集病样, 经稀释分离法进行病原菌分离纯化, 并通过致病性测定?形态学观察?生理生化特征观察及16S rDNA和gyrB序列分析相结合的方法对病原菌进行鉴定?结果表明, 选取的代表性菌株B1-0和B2-1均能使玉米叶片发病, 为革兰氏阳性致病菌, 产芽胞; 该病原菌需氧性?运动性?明胶液化?接触酶试验?柠檬酸盐利用?马铃薯腐烂试验均为阳性; 甲基红试验阴性; 能利用D-甘露醇?麦芽糖和葡萄糖, 不能利用甘油和肌醇, 不能水解淀粉, 在4℃?40℃和5%NaCl条件下均能生长?构建基于16S rDNA和gyrB的系统发育树, B1-0和B2-1与短小芽胞杆菌Bacillus pumilus(ATCC7061?BKS1-108?AUEC29?BP-hd-1?NMTD17和17)亲缘关系最近, 聚在一个分支?因此, 将该病原菌鉴定为短小芽胞杆菌B. pumilus?研究结果将为玉米细菌性叶部病害的研究和综合防治提供基础数据?     

Monitoring of atrazine treatment on soil bacterial,fungal and atrazine-degrading communities by quantitative competitive PCR

We report the development of quantitative competitive (QC) PCR assays for quantifying the 16S, 18S ribosomal and atzC genes in nucleic acids directly extracted from soil. QC-PCR assays were standardised, calibrated and evaluated with an experimental study aiming to evaluate the impact of atrazine application on soil microflora. Comparison of QC-PCR 16S and 18S results with those of soil microbial biomass showed that, following atrazine application, the microbial biomass was not affected and that the amount of 16S rDNA gene representing 'bacteria' increased transitorily, while the amount of 18S rDNA gene representing fungi decreased in soil. In addition, comparison of atzC QC-PCR results with those of atrazine mineralisation revealed that, in response to atrazine treatment, the amount of atzC gene increased transitorily in soil pre-treated with atrazine, suggesting that accelerated atrazine biodegradation in soil could be due to a transient increase in the size of the atrazine mineralising community.     

青海省不同生态区蚕豆根瘤菌16S rDNA分析

为了阐明青海省蚕豆根瘤菌的遗传多样性和亲缘关系,同时为发现和获得新的根瘤菌物种提供资源,采集和分离了青海省不同生态区蚕豆主栽品种青蚕14中的根瘤菌,并对其中分离到的6个菌株(CD1~6)进行16S rDNA鉴定分析。将6株蚕豆根瘤菌的全序列结果与NCBI中已报道的序列进行相似性比对,发现其相似度较高,其中供试菌株CD4与KF008225.1相似度最高,达到98%,其余均在95%到96%之间。6株供试菌分属4个菌属,CD1和CD2共属节细菌属,CD3属于分枝杆菌属,CD4和CD5属于快生根瘤菌属,CD6属于中慢生根瘤菌属,表明来自不同地区的蚕豆根瘤菌存在较大差异。聚类分析结果显示,蚕豆根瘤菌的6个菌株分属5个不同系统发育分支,证明青海省不同生态区蚕豆根瘤菌种类多样性较为丰富。     

甘薯茎腐病症状及其病原鉴定

 甘薯茎腐病是危害甘薯的一种严重病害,甘薯茎、叶柄、叶片和块根均可被害。该病典型症状是茎基部发黑和变软腐烂,叶发黄,茎和块根维管束黑褐色,引起块根腐烂、有臭味。通过对甘薯茎腐病典型症状样本的采集、病原菌的分离和纯化以及致病性测定,明确该病害是一种细菌病害。通过对甘薯茎腐病菌的菌体形态和培养特性观察发现,病原菌是革兰氏阴性细菌,菌体短杆状,大小约为2.36 μm×0.4 μm, 周生鞭毛,可在烟草上激发过敏性反应(HR)。Biolog测定、脂肪酸分析、16S rDNA序列分析、MALDI-TOF质谱鉴定和8个看家基因(dnaX、rplB、fusA、gapA、gyrA、purA、recA和rpoS)的序列系统发育分析,发现该病原菌与达旦提狄克氏菌Dickeya dadantii高度一致。这些结果说明,浙江省发生的小番薯病害是甘薯茎腐病,病原为D. dadantii。