基于环境DNA宏条码和底拖网的珠江河口鱼类多样性

文章采用环境DNA宏条码和底拖网对珠江河口鱼类多样性进行了研究, 并对两种方法进行了比较。利用环境DNA宏条码检测到了175种鱼类, 而利用底拖网采集到了47种鱼类, 结合两种方法共检测出179种鱼类, 隶属于15 目63科128属。其中两种方法共同识别了鱼类43种, 占总检测物种的24.02%, 基于底拖网的调查未能收集到基于环境DNA宏条码检测到的大多数物种。根据Shannon指数和Simpson指数显示, DNA宏条码所检测珠江河口鱼类群落α多样性显著高于底拖网方法(P<0.05)。两种方法的PCoA结果均显示珠江河口鱼类群落存在空间结构, 基于环境DNA宏条码的分析显示空间重叠更多。两种方法基于冗余分析均显示溶解氧和盐度是影响鱼类群落结构的主要环境因子。研究表明, 环境DNA 宏条形码是一种环保且可靠的评估方法, 将其搭载到现有调查可以更好地了解河口鱼类多样性。     

环境DNA技术在长江口鱼类多样性分析中的应用

研究采用高通量测序技术对长江口水域环境DNA(Environmental DNA, eDNA)样品进行分析,并与传统渔业资源调查结果对比,阐述长江口鱼类群落在其生境内的多样性特征,探讨eDNA技术在长江口水域鱼类多样性研究中的应用前景。结果显示, eDNA技术共检测到10目21科41属45种鱼类,各站点鱼类丰富度之间无显著差异,而多样性之间存在显著差异性。底拖网法共捕获11目16科29属33种鱼类。有18种鱼类在两种方法中均检测到,占鱼类总数的30%。两种方法检测到的鱼类中均以鲈形目(Perciformes)最多,其次是鲤形目(Cypriniformes),两种方法的结果均表明刀鲚(Coilia nasus)和凤鲚(Coilia mystus)为优势物种。研究表明环境DNA技术在长江口水域渔业资源监测中具有可行性,在禁捕环境下可根据实际情况采用不同方法对渔业资源进行监测。     

恶性转化试验及其相关试验体系在环境致癌因素检测中的应用

恶性转化试验及在其基础上建立起来的相关试验体系是当前用于环境致癌因素检测的主要手段,本以各种试验方法为核心,以试验中应用的靶材料为依据,从体内,体外两个方面,对现有的环境致癌因素检测方法进行了综述。     

涂片法与培养法在咽部菌群检测研究方面的应用比较

目的 探讨涂片法在咽部菌群研究方面的实际应用。方法 分别应用涂片法和培养法对26例健康成人的咽部菌群进行细菌密集度和多样性的检测。以秩序和检验等统计分析两种方法的差异。结果 两种方法用于密集度检测时无差异,（P＞0．05）;用于多样性检测时,结果显示出非优势菌多样性明显不同。而以优势菌的种类结果相比较时,两种方汉检测结果基本一致（P＞0．05）。结论 要了解人体某部位微生态的改变,依据统一的换算标准,在对细菌密集度和多样性进行检测的两项指标中,涂片法是能够替代培养法的,且作片法的确是一种实用、便捷且又较为可靠的检查方法。     

双探针显色原位杂交技术在乳腺癌HER2基因检测中的应用

目的:通过双探针显色原位杂交技术检测乳腺癌HER2基因的状态,评估双探针显色原位杂交技术的临床应用价值。方法:选取存档蜡块82例,分别用免疫组化及双探针显色原位杂交两种方法对Her-2基因及蛋白进行检测,并采用四格表卡方检验、配对卡方检验及Kappa检验作相关统计学分析。结果:两种方法检测结果不存在显著性差异(P0.05);就两种方法检测结果的一致性分析而言,两种方法所得出的检测结果存在较好的一致性(P0.05)。结论:双探针显色原位杂交技术检测乳腺癌HER2基因扩增结果与免疫组化检测HER2蛋白过表达结果高度相似,可作为检测HER2基因状态的有效方法。     

两种甲型肝炎病毒抗原快速检测方法的建立

目的建立两种甲型肝炎病毒抗原(HAV-Ag)检测试剂盒,并对其检测效果进行评价。方法生物素标记甲型肝炎病毒抗体(HAV-Ab)与辣根过氧化物酶标记亲和素联合应用建立甲型肝炎病毒抗原BA-ELISA检测法;同时使用辣根过氧化物酶标记HAV-Ab作放大系统建立双抗体夹心甲型肝炎病毒抗原ELISA检测试剂,对比两种检测方法的特异性、灵敏度及实际应用效果。结果用生物素标记甲型肝炎病毒抗体-辣根过氧化物酶标记亲和素作放大系统建立的甲型肝炎病毒抗原BA-ELISA检测法,较双抗体夹心ELISA检测方法灵敏度高1～2个稀释度;两种检测法均对10余种病毒无交叉,P/N值BA-ELISA检测法较高。结论甲型肝炎病毒抗原BA-ELISA检测法是一种灵敏度高,特异性好,方便快捷的检测方法,可广泛应用于甲型肝炎病毒研究及临床检测中。而甲型肝炎病毒抗原双抗体夹心ELISA检测法,检测灵敏度适中,操作简单,更适用于甲肝疫苗生产检定。     

DHPLC对猪肌肉组织差异表达EST的鉴定

采用DHPLC系统和Labwork4．0图像分析软件,对大白猪和广东地方品种蓝塘猪眼肌组织差异显示EST进行鉴定,两种方法均证实了差异显示条带的真实性。结果表明：用DHPLC系统能够准确而简捷的检测不同组织中mRNA表达的差异,是1种鉴定基因表达差异的有效方法,在研究基因表达,比较不同环境条件下动物组织的mRNA表达差异等方面具有广阔的应用前景。     

应用竞争PCR方法检测亚硝化细菌的研究

选用竞争PCR技术建立了亚硝化细菌的快速定量检测方法.实验以实验室分离、鉴定的一株亚硝化细菌提取的DNA为模板,设计特异性引物,制备特异性内标模板,进行竞争PCR实验;同时采用传统的平板计数法和吖啶橙荧光显微镜计数法两种方法进行细菌计数,与竞争PCR结果比较分析,建立了样品细菌数量与内标模板量的线性方程,并将其应用于海水养殖环境中亚硝化细菌的检测中.该方法具有简化检测过程、缩短细菌检测时间、无须昂贵仪器设备等优点,并克服有些环境微生物难以培养的困难,为将来有益菌在应用中实际存活和繁殖情况的监测提供了有力的技术支撑.     

近岸污染指示半知菌灰黄青霉(Penicillium griseo fulvum)的分子检测

【目的】通过分子方法检测近海污染环境优势种灰黄青霉,并为由此而推断污染程度做准备。【方法】根据GenBank中青霉属不同种和相近属种的ITS序列差异和灰黄青霉特有的IAO序列,设计了污染区优势种灰黄青霉的特异性引物AS1/RS4和IAO1/IAO2,建立相应的特异探针检测体系。通过PCR和套式PCR技术,分析比较两对特异序列检测灰黄青霉的差异。【结果】建立的分子检测体系可以排除其它近似或相关菌株干扰,从环境中扩增到目的基因片段。利用引物AS1/RS4作为核酸探针,通过套式PCR菌株DNA的检测灵敏度可达到10fg/μL,当仅有10个数量级分生孢子时即可检测出,从沉积物中检测灵敏度为102个数量级孢子/0.25g。特异酶基因IAO1/IAO2检测灵敏度较前者稍低。【结论】利用特异序列作为探针检测污染环境优势种灰黄青霉的方法可行,在一定范围内,灰黄青霉的出现频率及数量对污染程度有较好的指示作用。     

鼠尾胶原建立胶滴肿瘤药敏检测方法的初步研究

目的:用鼠尾胶原建立胶滴肿瘤药敏检测方法(CD-DST),探讨此方法在体外药物敏感性检测中的可行性.方法:建立Hela细胞在鼠尾胶原中培养的三维立体模型;在此基础上进行药物敏感性检测,用MTT、CD-DST两种药敏检测方法检测Hela细胞对4种化疗药物的敏感性.结果:Hela细胞在鼠尾胶原凝胶滴中生长良好,呈克隆样增殖、放射状生长;两种药敏检测方法有较好的一致性.结论:用鼠尾胶原建立的CD-DST技术是可行的,在体外药敏检测中具有一定的临床应用价值.     

A comparison of methods for measuring primary productivity and community respiration in streams

Carbon dioxide and oxygen exchange procedures for measuring community metabolism (two open stream methods and three chamber methods) were compared on the same reach of a third-order stream. Open stream methods were complicated by high diffusion rates and yielded net community primary productivity estimates lower than those obtained with chamber methods. Chamber methods yielded variable productivity and respiration data. However, when normalized for chlorophyll a, productivity estimates from the chamber methods were within an expected range for the system. Balances of photosynthesis and respiration from the chamber methods were similar between methods and indicated that autotrophic or heterotrophic processes could dominate the system. Considerations in applying the various procedures are discussed.     

A comparison of the accuracy and precision of several open-water oxygen productivity techniques

Several methods for the estimation of the reaeration coefficient were compared by determining the ability of the methods to recover the correct K value from a computer-simulated stream oxygen record affected by a variety of non-ideal conditions. Noisy data and long observation intervals were not a serious problem for most methods. Saturating photosynthesis, fluctuating light intensity, afternoon depression and temperature variation caused failures by some methods but were well handled by others. Serious impairment of all methods occurred with low productivity or high K. In general, the best-performing methods were the modified hysteresis, nighttime regression, daytime regression, Odum and Hornberger-Kelly daytime methods.     

血清钠、钾离子的均相直接测定方法研究进展

血清钠离子和钾离子的测定在临床诊断上意义重大,其常规检测方法火焰光度法和离子选择性电极法都需要昂贵的仪器且操作复杂,因此近年来开发了一些均相直接测定方法。本文综述了近年研制出的血清中钠、钾离子的各种均相直接测定方法,评述了各种直接测定方法的优、缺点。血清中钠、钾离子进行均相直接测定有着准确度高、重复性好等优点,可在临床生化自动化分析仪上应用。     

森林生态系统CO2通量的研究方法及研究进展

介绍了测量森林生态系统CO2通量的微气象法和箱式法。其中,微气象学方法着重介绍了涡旋相关法和驰豫涡旋积累法的基本原理及数据分析过程中应注意的问题。并简要介绍了能量平衡法和空气动力学法。箱式法主要介绍了其测定基本原理和数据的模型化处理及应注意的问题。同时,对近年来欧洲和美洲在森林生态系统CO2通量研究中所取得的进展进行了概述。     

Predicting allele frequencies in DNA pools using high density SNP genotyping data

To evaluate the ability to use DNA pools with the Illumina Infinium genotyping platform, two sets of gradient pools were created using two pairs of highly inbred chicken lines. Replicate pools containing 0%, 10%, 20%, 40%, 60%, 80%, 90% and 100% of DNA from line A vs. B or line C vs. D were created, for a total of 28 pools. All pools were genotyped for 12 046 SNPs. Three frequency estimation methods proposed in the literature (standard, heterozygote‐corrected and normalized) were compared with three alternate methods proposed herein based on mean square error (MSE), bias and variance of estimated vs. true allele frequencies and the fit of regression of estimated on true frequencies. The three new methods had average square root MSE of 4.6%, 4.6% and 4.7% compared to 5.2%, 5.5% and 11.2% for the three literature methods. Average absolute biases of the literature methods were 2.4%, 2.7% and 8.2% compared to 2.4% for all new methods. Standard deviations of estimates were also smaller for the new methods, at 3.1%, 3.2% and 3.2% compared to 3.5%, 4.0% and 5.0% for previously reported methods. In conclusion, intensity data from the Illumina Infinium Assay can be efficiently used to estimate allele frequencies in pools, in particular using any of the new methods proposed herein.     

Methods and Errors in Measurements of Synovial Fluid Volume in Stifles with Low Volume and High Viscosity Synovial Fluid. An Experimental Study in Goats

Synovial fluid (SF) volume was calculated using various methods in the stifles of goats, in which the cranial cruciate ligament had been transected on one side. Measurements were performed prior to surgery and again 4,8, and 18 weeks following surgery, by measuring the dilution of an injected radioactive tracer diluted by the SF. Later, 7 months following surgery, SF volume measurements using simple arthrocentesis were performed on stifles in 9 of the goats, and the SF that could not be aspirated, was calculated using 2 indirect methods simultaneously on identical fluids in 3 of these goats. SF was also collected directly during staged arthrotomy of the stifles in 4 goats. There were conflicting results between methods, but the resulting calculated SF volumes seemed to be larger in the operated stifles compared to the controls for all the methods at about the same degree. The 2 indirect methods used to calculate the fluid remaining in the joints following arthrocentesis gave disparate volume calculations. The experiments revealed sources of error in all methods. Direct methods failed to acquire the total fluid volume, and indirect methods were subject to improper mixing and escape of the injected fluid or synovial fluid or both. It was concluded that none of the methods could be used to measure the “true” volume of SF, if such a concept exists and can be defined. None of the methods were considered reliable to compare volumes in different type of joints containing this type of fluid. It was, however, concluded that all the methods gave indication of increased SF volume present on a relative basis when paired joints were compared.     

A simulation-based evaluation of methods for inferring linear barriers to gene flow

Different analytical techniques used on the same data set may lead to different conclusions about the existence and strength of genetic structure. Therefore, reliable interpretation of the results from different methods depends on the efficacy and reliability of different statistical methods. In this paper, we evaluated the performance of multiple analytical methods to detect the presence of a linear barrier dividing populations. We were specifically interested in determining if simulation conditions, such as dispersal ability and genetic equilibrium, affect the power of different analytical methods for detecting barriers. We evaluated two boundary detection methods (Monmonier's algorithm and WOMBLING), two spatial Bayesian clustering methods (TESS and GENELAND), an aspatial clustering approach (STRUCTURE), and two recently developed, non-Bayesian clustering methods [PSMIX and discriminant analysis of principal components (DAPC)]. We found that clustering methods had higher success rates than boundary detection methods and also detected the barrier more quickly. All methods detected the barrier more quickly when dispersal was long distance in comparison to short-distance dispersal scenarios. Bayesian clustering methods performed best overall, both in terms of highest success rates and lowest time to barrier detection, with GENELAND showing the highest power. None of the methods suggested a continuous linear barrier when the data were generated under an isolation-by-distance (IBD) model. However, the clustering methods had higher potential for leading to incorrect barrier inferences under IBD unless strict criteria for successful barrier detection were implemented. Based on our findings and those of previous simulation studies, we discuss the utility of different methods for detecting linear barriers to gene flow.     

Evaluation of Assay Methods for Hepatitis-Associated Antigen

Assay methods for hepatitis-associated antigen (HAA) were evaluated for sensitivity, or reproducibility, or both in a series of three trials in which both research and service-oriented laboratories participated. Agar-gel diffusion (AGD) methods were found to be the least sensitive and reproducible of the commonly employed assay methods. Complement fixation (CF) tests were consistently more sensitive than either AGD or counterelectrophoresis (CEP) methods for detection of HAA. With judicious choice of the antibody reagent, sensitivity of CEP techniques was equivalent to CF methods of HAA detection. None of the three major assay methods (AGD, CEP, or CF) compared in this study were capable of consistently detecting HAA when it was present in relatively low concentrations in human serum.     

近红外光谱技术快速检测原料乳中掺杂物

采用近红外光谱技术结合化学计量学方法,对原料乳中常见的2种掺杂物——大豆分离蛋白与植脂末进行定量分析研究。先通过不同光谱预处理方法结合偏最小二乘法（PLS）建模评价不同预处理方法的效果,结果表明通过平滑处理结合多元散射校正（MSC）进行光谱预处理效果最佳,大豆分离蛋白PLS定量模型相关系数（R2）与交叉验证均方差（RMSECV）分别为0.980 9、0.127 5,植脂末PLS模型分别为0.972 2、0.130 8。随后比较了不同建模方法的效果,结果发现：采用径向基神经网络（RBF）对大豆分离蛋白的建模效果最佳,R2为0.999 4,测试集均方根误差为0.003 1;采用广义回归神经网络（GRNN）方法对植脂末建模效果最佳,R2为0.998 9,测试集均方根误差为0.004 5。因此,合理结合近红外光谱技术与化学计量学方法可快速、准确检测原料乳中大豆分离蛋白和植脂末这2种掺杂物含量。     

Comparison of methods for determination of vitamin B12 in microbial material

Three different methods for the measurement of vitamin B12 were compared: two spectrophotometric methods and an HPLC one. When the pure vitamin was used, the results obtained using all three methods were similar, but when samples from microbial material were used, the results were different. The HPLC method could distinguish the true vitamin B12 from the different vitamin B12 analogues whereas the spectrophotometric methods could not.