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1.
用ISSR标记技术对来自国内外的73份豌豆材料进行遗传多样性分析,结果表明,100个ISSR引物中共筛选出11个多态性明显、条带清晰、反应稳定的引物,73份材料DNA共扩增出91条条带,其中78条为多态性条带,平均每个引物扩增的条带数为8.2条,多态性比率为86.4%。Shannon多样性指数平均为0.420 2,每个位点的有效等位基因数为1.451 8,品种间遗传相似系数变幅为0.406 5~0.934 0,表现出丰富的遗传多样性。利用UPGMA聚类分析,以遗传相似系数0.52为界限,73份材料划分为5类,聚类基本符合地理来源相近的材料聚为一类,呈现出一定的地域性分布规律。 相似文献
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Transmission patterns of Salmonella in a swine production unit were investigated by statistical analysis of the spatial distribution of isolates and the clustering of genotypes over a 12-week period. The study unit was a breeding-gestation building in a single-site farrow-to-finish swine production system. During the summer of 2003, 1746 pen floor samples were collected during 6 visits conducted at 2-week intervals. Genotyping was performed on the 107 Salmonella isolates obtained using repetitive sequence PCR (3 primers: REP, BOX, ERIC). Genetic similarity was evaluated by DNA fragment matching and hierarchical cluster analysis based on genetic similarities. For each visit, the distance at which spatial clustering of Salmonella isolates occurred was estimated using second order analyses. Significant spatial clustering of Salmonella up to a distance of 15.2m was identified for 4 of the 6 farm visits, those for which the prevalence of Salmonella was the highest. Cluster analysis of genetic similarities identified 4 groups of Salmonella isolates at the level of at least 85% similarity in rep-PCR fragment matching patterns. Genetic clusters were relatively homogeneous for time of visit, with each genetic cluster consisting of isolates from the same or temporally adjacent visits. The correlation between genetic similarity and spatial proximity between pairs of Salmonella isolates, and the correlation between these measures and differences in time of sampling, were evaluated using Mantel's r. There was a strong positive correlation (r=0.62, p<0.0001) between genetic distance and time of sampling, indicating evolution of the Salmonella population over time. For 4 of the 6 visits, a pattern of decreasing genetic similarity between isolates with increasing distance between sampling locations was apparent. However, when viewed over all 6 visits, Salmonella was concentrated in one area of the building and did not move in any specific direction. These results suggest that a particular genotype of Salmonella, if introduced in the breeding-gestation unit of a swine farm would evolve slowly over short time intervals; its spatial distribution would be limited primarily to adjacent or nearby pens. In this study spatial analysis (e.g., Ripley's K-function) and matrix correlation methods (e.g., Mantel's r) expanded upon cluster analysis of genotypic similarities to provide additional interpretable information regarding the spatial distances to which Salmonella is transmitted over time in swine production facilities. 相似文献
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利用EST-SSR标记分析西南扁穗牛鞭草种质的遗传多样性 总被引:2,自引:2,他引:0
利用禾谷作物EST-SSR标记对采自我国西南地区的40份野生扁穗牛鞭草和3份扁穗牛鞭草国审品种的遗传变异和亲缘关系进行了研究。试验筛选出23对引物对43份供试材料进行扩增,共获得323条带,其中多态性条带261条,多态性条带比率(PPB)达80.4%,多态信息含量(PIC)为0.354~0.500,平均值为0.474,遗传相似系数(GS)为0.690~0.913,表现出丰富的遗传多样性。聚类分析结果表明,各供试材料间的聚类与其地理来源及形态特征具有一定的相关性。5 个扁穗牛鞭草地理类群间的分子方差分析(AMOVA)揭示了供试的扁穗牛鞭草类群内的遗传变异占总变异的95.32%,类群间变异占总变异的4.68%。表明禾谷作物的EST-SSR能用于扁穗牛鞭草遗传多样性研究,是一种有效的分子标记。本研究结果为扁穗牛鞭草种质的收集、利用及育种提供了理论依据。 相似文献
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冰草属植物种质资源遗传多样性的ISSR分析 总被引:3,自引:0,他引:3
用ISSR标记对来自国内外的33份冰草材料的遗传多样性进行了检测。从93条ISSR引物中共筛出11条能扩增出清晰条带并具有多态性的引物,33个样品DNA共获得84个扩增位点,其中多态性位点59个,平均每个引物扩增位点为7.64个。品种间遗传相似系数在0.083~0.706,表现出丰富的遗传多样性。利用UPGMA聚类分析,以遗传相似系数0.52为界限,33份材料划分为4类,聚类基本符合地理来源相近的材料聚为一类,呈现出一定的地域性分布规律。 相似文献
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通过对DNA提取方法及RAPD反应体系进行探讨,建立了适应偃麦草基因组DNA提取的方法及优化的RAPD反应体系。在此基础上,依据Jaccard相似系数,采用UPGMA方法进行聚类,判定32份偃麦草种质材料间的亲缘关系及遗传多样性。结果表明:(1)改良常规CTAB法,即对样品先进行洗涤并提高CTAB含量到3%可提高偃麦草DNA的提取质量。(2)对100条随机引物进行筛选,共筛选出18条多态性高、重复性好的随机引物,以此对32份材料进行PCR扩增,共扩增出264条带,多态性条带为93.7%。(3)以遗传相似系数为依据,对32份偃麦草材料进行聚类分析,在相似系数为0.373处可将供试偃麦草种质资源划分为5大类群。 相似文献
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祁连山高寒草甸生态系统昆虫群落特征 总被引:1,自引:0,他引:1
2009年7月中旬于祁连山地区的中国科学院海北高寒草甸生态系统研究站,在滩地草甸、金露梅(Potentilla fruticosa)灌丛、山坡草甸和沼泽化草甸4个不同的生境中对昆虫进行百网取样,共获得908头昆虫。分别隶属于10目42科 65种。发现该地区双翅目昆虫是最繁盛的类群:第2个优势目为膜翅目,其次优势目为鞘翅目。昆虫物种多样性和丰富度依次为滩地草甸>金露梅灌丛>山坡草甸>沼泽化草甸;均匀度差异不大;优势度指数沼泽化草甸最高,滩地草甸最低。滩地草甸和山坡草甸昆虫群落的相似性最大;其次是金露梅灌丛;差异最大的是沼泽化草甸。通过分析发现,生境的变迁和气候的变化引起了昆虫群落结构和多样性的差异变化。 相似文献
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《科技视界》2014,(6)
For a particular clustering problems, selecting the best clustering method is a challenging problem.Research suggests that integrate the multiple clustering can improve the accuracy of clustering ensemble greatly. A new clustering ensemble approach based on the similarities in 2-mode networks is proposed in this paper. First of all, the data object and the initial clustering clusters transform into 2-mode networks, then using the similarities in 2-mode networks to calculate the similarity between different clusters iteratively to refine the adjacency matrix, K-means algorithm is finally used to get the final clustering, then obtain the final clustering results.The method effectively use the similarity between different clusters,example shows the feasibility of this method. 相似文献
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The spatial heterogeneity of Bovine Spongiform Encephalopathy (BSE) was analysed on the 84 cases confirmed in western France (WF) between August and December 2000, when both the Mandatory Reporting System and an active surveillance on cattle at risk were running. Ninety-four percent of these cases were born between June 1993 and June 1996, and we analysed the location at birth. One disease mapping and two clustering methods (Scan of Kulldorff and the method of Besag and Newell) were used. In order to attenuate the contrasts artificially created by the standard disease mapping method (over-dispersion), we estimated the Standard Incidence Ratio (SIR) with a Bayesian method (Poisson-Gamma model) allowing a smoothing of the estimators. The geographical location of interest was the "canton", that divided the total area into 526 geographical units. The background population (2.6 million cattle) was obtained from the Agricultural Census 2000. We tested the hypothesis of a homogenous spatial distribution of the BSE risk where the expected number of BSE cases per unit area was obtained by applying the overall BSE rate in WF to each "canton", standardised on the type of breed, dairy versus beef suckler. The SIR ranged from 0.80 to 2.18 and the spatial distribution of BSE cases was significantly heterogeneous. Two spatial clusters were detected with the spatial scan statistics of Kulldorff and the method of Besag and Newell (18 to 20 observed BSE-cases per cluster with a radius of 45 km) centred on the "département" of C?tes-d'Armor and Mayenne. Another cluster was detected with the method of Besag and Newell (9 observed BSE-cases) in the "département" of Finistère. The results proved that the risk of BSE is linked to the geographical location in the area of the study. 相似文献
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BackgroundTicks are one of the most common external parasites in dogs, and are associated with the transmission of a number of major zoonoses, which result in serious harm to human health and even death. Also, the increasing number of pet dogs and pet owners in China has caused concern regarding human tick-borne illnesses. Accordingly, studies are needed to gain a complete understanding of the bacterial composition and diversity of the ticks that parasitize dogs.ObjectivesTo date, there have been relatively few reports on the analysis of the bacterial community structure and diversity in ticks that parasitize dogs. The objective of this study was to investigate the microbial composition and diversity of parasitic ticks of dogs, and assessed the effect of tick sex and geographical region on the bacterial composition in two tick genera collected from dogs in China.MethodsA total of 178 whole ticks were subjected to a 16S ribosomal RNA (rRNA) next generation sequencing analysis. The Illumina MiSeq platform targeting the V3–V4 region of the 16S rRNA gene was used to characterize the bacterial communities of the collected ticks. Sequence analysis and taxonomic assignment were performed using QIIME 2 and the GreenGene database, respectively. After clustering the sequences into taxonomic units, the sequences were quality-filtered and rarefied.ResultsAfter pooling 24 tick samples, we identified a total of 2,081 operational taxonomic units, which were assigned to 23 phyla and 328 genera, revealing a diverse bacterial community profile. The high, moderate and low prevalent taxa include 46, 101, and 182 genera, respectively. Among them, dominant taxa include environmental bacterial genera, such as Psychrobacter and Burkholderia. Additionally, some known tick-associated endosymbionts were also detected, including Coxiella, Rickettsia, and Ricketssiella. Also, the potentially pathogenic genera Staphylococcus and Pseudomonas were detected in the tick pools. Moreover, our preliminary study found that the differences in microbial communities are more dependent on the sampling location than tick sex in the tick specimens collected from dogs.ConclusionsThe findings of this study support the need for future research on the microbial population present in ticks collected from dogs in China. 相似文献
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Kokosharov T 《The Onderstepoort journal of veterinary research》2000,67(4):297-300
Bacterial colonization and endotoxin production were investigated before and after experimental Salmonella gallinarum infection in 8-week-old female broiler chickens. These parameters were assayed by means of colony forming units test (CFU) and the Limulus Amebocyte Lysate test (LAL), respectively. Birds were infected per os with 1,5 x 10(9) CFU/ml of wild strain of S. gallinarum isolated from a dead hen. Approximately 1,5 x 10(2); 1,3 x 10(2) and 1,2 x 10(2) CFU of S. gallinarum were recorded from 1 g of liver, 1 g of spleen and 1 ml of blood from the chickens on day 1 post infection. By day 4 corresponding data were 3,7 x 10(4); 4,8 x 10(3) and 1,1 x 10(3) respectively and on day 7 10(5) CFU were present in all three specimen types. The liver and spleen of dead birds were contaminated with more than 10(7) CFU per g. The endotoxin from S. gallinarum was found to have an activity of 1,5; 12,0 and 15,0 endotoxin units (EU)/ml on day 1, 4 and 7 after infection, respectively. No endotoxin activity was established in the blood of the control group (before infection) by the LAL test. This is the first time the connection between the amount of live S. gallinarum in the blood, liver and the circulating level of endotoxin in the blood during the infectious stage of experimental acute fowl typhoid, has been demonstrated. 相似文献
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基于AFLP的燕麦遗传多样性研究 总被引:9,自引:5,他引:4
采用AFLP分子标记技术对来自中国、加拿大、澳大利亚和欧洲等国家的34个有代表性的饲用燕麦品种及8个裸燕麦品种进行遗传多样性分析,从30 对EcoRI/MseI引物组合中筛选出5 对多态性和清晰度较高的引物组合,共获得268条带,其中多态带185条,平均多态性检出率为69.0%,E AGG/M CTA 的扩增效率最高达78.6%。由Nei’s指数(h)估测,供试品种平均变异为0.1664,平均Shannon’s信息指数估计值为0.2206;42个燕麦品种间遗传相似系数为0.4881~0.9880,遗传距离的变化范围是0.0120~0.7172。通过AFLP 数据构建燕麦的UPGMA 系统树,在遗传相似系数0.748水平,所有供试品种可聚为6类。皮燕麦与裸燕麦在遗传相似度0.59处被明显分为2类,与形态学分类结果一致。由AFLP揭示的品种间遗传关系与品种实际来源基本一致,品种的遗传距离与其地理分布关系密切。 相似文献
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Ainoa Nieto‐Claudin Fernando Espern Stephen Blake Sharon L. Deem 《Zoonoses and public health》2019,66(8):900-908
Antimicrobial resistance (AMR), encoded by plasmid‐mediated AMR genes (ARGs), is an increasing global public health threat. Wildlife play a fundamental role as sentinels, reservoirs and potential vectors of ARGs. For the first time in Galapagos, we have identified and quantified the presence of ARGs in free‐living giant tortoises (Chelonoidis porteri). We performed ARG analyses by quantitative PCR of faeces collected from the cloaca of 30 tortoises widely distributed across Santa Cruz Island. Validated samples (n = 28) were analysed by a panel of up to 21 different ARGs and all 28 tortoise samples were positive to one or more genes encoding resistance. Thirteen of 21 tested ARGs were present in at least one sample, and 10 tortoises (35.7%) had a multi‐resistant pattern. We recommend additional research so we may more fully understand resistance patterns across taxa and geographical locations throughout the Galapagos archipelago, and the implications of ARGs for the health of wildlife, domestic animals, and humans. In this study, we found 100% of sampled giant tortoises had ARGs present in their faeces, suggesting a large‐scale distribution of these genes within the archipelago. 相似文献
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Over one-third of the cases of BSE in Switzerland have been born after the feed ban of December 1, 1990. Evidence for the geographical clustering of these cases emerged in two distinct regions. All the 354 BSE cases recorded until June 30, 2000 (set A), and the 376 cases recorded up to May 14, 2001 (set B), were georeferenced to the centres of the communities in which the herds of origin were located, and control populations were georeferenced to the centres of the communities in which these herds were located at the time of the census. The latitudes and longitudes of these centres were used in the statistical analysis of the spatial clustering. The Cuzick-Edwards test and the spatial scan statistics were applied to assess the significance of the clusters, while controlling for the spatial distribution of the underlying cattle population. There was global clustering of the cases born after the ban, and distinct and significant (P<0.05) spatial clusters were repeatedly identified in the two case datasets, and in several control populations (all cases born before the feed ban on a random sample of control farms) in terms of cattle density by region or cow density by region. Differential reporting was excluded as the underlying reason for the observed clusters. 相似文献
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本研究旨在建立乳腺康注射液质量标准。按照《中国药典》(2015版)相关要求,分别建立乳腺康注射液中甘草、青皮、蒲公英的薄层色谱定性鉴别和重金属的检查方法并规定限度,采用HPLC法建立甘草苷、甘草酸铵、橙皮苷及咖啡酸的含量测定方法并规定限度。结果表明,甘草、青皮、蒲公英的定性鉴别专属性强;甘草苷在0.0459~0.7340 μg,甘草酸铵在0.0661~1.0580 μg,橙皮苷在0.0592~0.9470 μg,咖啡酸在0.0384~0.6140 μg浓度与峰面积呈良好的线性关系;相关系数r分别为0.997、0.9990、0.9999、1.000;甘草苷、甘草酸铵、橙皮苷及咖啡酸的平均加样回收率分别为101.25%、99.87%、98.39%、103.49%,相对标准偏差(RSD)值分别为4.82%、3.63%、2.94%、0.85%;乳腺康注射液中含甘草苷、甘草酸铵、橙皮苷及咖啡酸分别不低于88.90、138.48、136.50、21.54 μg/mL;按乳腺康注射液每日最大使用剂量计算,铅、镉、砷、汞、铜分别不得超过23、3、6、2及150 μg。本研究建立的质量标准可为控制乳腺康注射液的质量提供参考。 相似文献
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The aim of this study was to establish the quality standard of Ruxiankang (RXK) injection. According to the relevant requirements of the Chinese Pharmacopoeia (2015 edition), TLC identification,related substances examination and heavy metal examination method of RXK injection were established and the limits were determined. HPLC method was used to establish the content determination method of liquiritin, ammonium glycyrrhizinate, hesperidin and caffeic acid, and determined the limit. The specificity of Glycyrrhizae Radix et Rhizoma, Citri Reticulatae Pericarpium and Taraxaci Herba was strong. Liquiritin in 0.0459 to 0.7340 μg, ammonium glycyrrhizate in 0.0661 to 1.0580 μg, hesperidin in 0.0592 to 0.9470 μg, caffeic acid in the 0.0384 to 0.6140 μg concentration showed a good linear relationship with peak area. The correlation coefficients were 0.997,0.9990,0.9999 and 1.000,respectively. The average recoveries were 101.25%, 99.87%, 98.39% and 103.49%,respectively. The RSD values were 4.82%, 3.63%, 2.94% and 0.85%,respectively. The contents of liquiritin, ammonium glycyrrhizinate, hesperidin and caffeic acid of RXK injection were not less than 88.90, 138.48, 136.50 and 21.54 μg/mL,respectively. According to the maximum daily dose of RXK injection, Pb,Cd, As, Hg and Cu should not exceed 23,3,6,2 and 150 μg, respectively. The quality standard established in this study could provide reference for controlling the quality of RXK injection. 相似文献
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4种氟喹诺酮类药物在肉鸡组织中残留的研究 总被引:8,自引:1,他引:8
采用高效液相色谱法同时检测肉鸡肌肉、脂肪、肝脏和肾脏组织中4种氟喹诺酮类药物(FQS)的残留。检测条件为:采用HP-StableBond C18分析柱(5 μm,250 mm×4.6 mm),以15 mmol/L的四丁基溴化铵溶液-乙腈(体积比94∶6)为流动相(用乙酸钠缓冲液调pH3.6),流速1.0 ml/min,柱温30℃;采用荧光检测器检测,激发波长280 nm,发射波长460 nm。测定结果表明,该方法对FQS的最低检测限为0.92 μg/kg,在5.00~100.00 μg/mg的线性范围内,溶液含量与峰面积的相关系数达0.9998以上。在高、中、低3种含量水平下对所测肉鸡组织中4种FQS进行回收率测定,结果为74%~99%,相对标准偏差低于6.5%,该方法能同时测定4种FQS在动物组织中的残留,具有简便、准确、灵敏度较高的特点,符合痕量测定的要求。 相似文献
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[目的]建立全自动石墨消解—电感耦合等离子体发射光谱(ICP-OES)、电感耦合等离子体质谱(ICP-MS)分析方法对马奶中的常量及痕量矿物质元素进行测定。[方法]采用全自动石墨消解仪对样品进行前处理,采用电感耦合等离子体发射光谱法对马奶中钾、钠、钙、磷4种常量元素进行测定,利用重量法配制标准溶液,以铑元素作为内标,采用电感耦合等离子体质谱法对马奶中铝、砷、硼、钡、铍、镉、钴、铬、铜、铁、锂、镁、锰、镍、铅、锑、锡、锶、钛、铊、钒、锌、硒共23种元素进行测定。利用生物成分分析标准物质对结果进行质量控制。[结果]常量元素在0~20 μg/mL、痕量元素在0~200 ng/mL 具有良好的线性关系,标准曲线相关系数均可达到0.999以上,ICP-MS法各元素检出限在0.001 10~1.578 ng/mL,ICP-OES法各元素检出限在0.010 0~0.068 8 μg/mL;多次对生物成分分析标准物质中矿物质元素含量测定结果的相对标准偏差均小于11%(n=6),且测定结果与标准值相符。[结论]该方法线性相关性、检出限、准确度等方面能够满足准确、高效测定马奶中矿物质元素含量的要求。 相似文献
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