Methods for Detecting Food-borne Enteroviruses

A method previously reported for detecting virus in a model system composed of cottage cheese contaminated with coxsackievirus type A9 has been adapted to detecting selected strains of enteroviruses in a variety of foods. Bentonite is omitted and serum is added for extracting virus from low-protein foods. Samples of foods, usually 25 g, must contain at least 3 to 4 plaque-forming units for a 50% probability of detecting virus. Sensitivity in detecting echovirus type 6 was lower than that for the other viruses used. After extraction from potato salad, poliovirus type 2 was completely reactivated if it had been neutralized with coproantibody, but it was only partially reactivated if neutralized with hyperimmune rabbit serum.     

细胞凋亡检测方法新进展

细胞凋亡是生命科学研究的热点之一,检测细胞凋亡的方法层出不穷。目前,用于体外细胞凋亡检测的方法已相对成熟,比如:流式细胞术、TUNEL检测法、DNA片断检测等。而用于体内细胞凋亡检测的试剂则正在研究之中,各种检测试剂不断出现。其中,Annexin V、Synap-totagmin I-C2A、ApoSense家族分子与其他检测试剂相比具有一定的优势。该文在介绍几种常用的体外细胞凋亡检测方法的同时,重点介绍上述三种试剂。     

转基因水稻检测方法的研究进展

近年来,转基因作物在全球得到了迅猛发展,1988年第一批水稻转基因植株问世以来,各国科学家在水稻转基因研究领域取得了一系列成果,而对转基因水稻及其产品的检测,也成为世界各国公众关心的热点,从PCR法、基因芯片法等讨论转基因水稻的检测方法的研究进展,让读者对转基因水稻检测方法有初步的认识和了解,对开展转基因水稻检测的研究工作有一定的参考价值。     

Design of a DNA chip for detection of unknown genetically modified organisms (GMOs)

MOTIVATION: Unknown genetically modified organisms (GMOs) have not undergone a risk evaluation, and hence might pose a danger to health and environment. There are, today, no methods for detecting unknown GMOs. In this paper we propose a novel method intended as a first step in an approach for detecting unknown genetically modified (GM) material in a single plant. RESULTS: A model is designed where biological and combinatorial reduction rules are applied to a set of DNA chip probes containing all possible sequences of uniform length n, creating probes capable of detecting unknown GMOs. The model is theoretically tested for Arabidopsis thaliana Columbia, and the probabilities for detecting inserts and receiving false positives are assessed for various parameters for this organism. From a theoretical standpoint, the model looks very promising but should be tested further in the laboratory. AVAILABILITY: The model and algorithms will be available upon request to the corresponding author.     

AFLP标记在研究家蚕遗传多态性方面的应用

AFLP是一种多态检出效率很高的分子标记技术,在构建遗传图谱,遗传多态性研究,重建分子系统演化树,品种鉴定,基因克隆等众多研究领域有着其它分子标记技术不可比拟的优势。本文在前人用AFLP技术对植物多态性研究的基础上,将AFLP用于家蚕的遗传多态性研究,结果发现在家蚕中同样具有丰富的AFLP标记的多态性。由此暗示AFLP技术亦适合研究家蚕等昆虫类动物的遗传多态性,构建遗传图谱,或用于其分子生态学,分子进化和分类等方面的研究。此外本文还探讨了适合于家蚕等昆虫的AFLP分析的实验条件。     

Simple,filter-based PCR detection of Thelohania solenopsae (Microspora) in fire ants (Solenopsis invicta)

Thelohania solenopsae is a microsporidian parasite that may serve as a biological control agent for the red imported fire ant, Solenopsis invicta. A rapid, filter-based PCR amplification method detecting a portion of the small-subunit ribosomal RNA gene was developed to facilitate field studies detecting the parasite in fire ants. Processing ant homogenates with a commercially available membrane-based system, FTA Classic Card technology, compared favorably with traditional DNA extraction and PCR amplification methods. As few as 100 spores were detected. The FTA membrane system is a simple, extraction-free method for detecting T. solenopsae in fire ants, and allows for easy archival storage of DNA samples.     

Stereoscopic and contrast-defined motion in human vision.

There is considerable evidence for the existence of a specialized mechanism in human vision for detecting moving contrast modulations and some evidence for a mechanism for detecting moving stereoscopic depth modulations. It is unclear whether a single second-order motion mechanism detects both types of stimulus or whether they are detected separately. We show that sensitivity to stereo-defined motion resembles that to contrast-defined motion in two important ways. First, when a missing-fundamental disparity waveform is moved in steps of 0.25 cycles, its perceived direction tends to reverse. This is a property of both luminance-defined and contrast-defined motion and is consistent with independent detection of motion at different spatial scales. Second, thresholds for detecting the direction of a smoothly drifting sinusoidal disparity modulation are much higher than those for detecting its orientation. This is a property of contrast-modulated gratings but not luminance-modulated gratings, for which the two thresholds are normally identical. The results suggest that stereo-defined and contrast-defined motion stimuli are detected either by a common mechanism or by separate mechanisms sharing a common principle of operation.     

动态浊度法检测C群脑膜炎球菌多糖原液细菌内毒素含量

采用动态浊度法对多批C群脑膜炎球菌多糖原液进行细菌内毒素含量检测,同时设供试品干扰试验,并与凝胶限量法进行对比分析。从而建立了C群脑膜炎球菌多糖原液细菌内毒素定量检测方法和质量控制指标。     

Characterization of Bacteria by Their Degradation of Amino Acids

A procedure for detecting the degradation of amino acids by microorganisms is described, and examples of its use in the characterization of bacteria are presented. The procedure involves inoculating a buffered solution of amino acids with a suspension of bacteria, incubating, chromatographing a sample of the suspension, and detecting degradation in terms of absence of ninhydrin-positive spots.     

Comparing functional connectivity via thresholding correlations and singular value decomposition

We compare two common methods for detecting functional connectivity: thresholding correlations and singular value decomposition (SVD). We find that thresholding correlations are better at detecting focal regions of correlated voxels, whereas SVD is better at detecting extensive regions of correlated voxels. We apply these results to resting state networks in an fMRI dataset to look for connectivity in cortical thickness.     

捕捉法ELISA检测脊髓灰质炎IgA抗体方法的建立与应用

建立了一种检测脊髓灰质炎(简称脊灰)IgA抗体的捕捉法ELISA(Aac-ELISA)。方法敏感,快速,特异,用于检测144份脊灰可疑病人的血清,IgA抗体检出率为77.8％(112/144).而这些血清的IgM抗体检出率为65.2％(94/144)。如同时检测IgM和IgA抗体,则阳性率可达91.7％(132/144)。麻痹后1～3天内IgA的检出率为76.5％(13/17),4～7天内为95％(19/20)。最长检出IgA的一例可疑病人,其血清收集于病后第59天。本方法在一部分16天后可疑病人IgM阴性血清中查出IgA阳性,故可以作为查IgM抗体诊断方法的补充,尤其适用于诊断感染后未能及时收到血清标本,IgM已经转阴而IgA抗体仍为阳性的病人。     

A program for selecting DNA fragments to detect mutations by denaturing gel electrophoresis methods.

A computer program was developed to automate the selection of DNA fragments for detecting mutations within a long DNA sequence by denaturing gel electrophoresis methods. The program, MELTSCAN, scans through a user specified DNA sequence calculating the melting behavior of overlapping DNA fragments covering the sequence. Melting characteristics of the fragments are analyzed to determine the best fragment for detecting mutations at each base pair position in the sequence. The calculation also determines the optimal fragment for detecting mutations within a user specified mutational hot spot region. The program is built around the statistical mechanical model of the DNA melting transition. The optimal fragment for a given position is selected using the criteria that its melting curve has at least two steps, the base pair position is in the fragment's lowest melting domain, and the melting domain has the smallest number of base pairs among fragments that meet the first two criteria. The program predicted fragments for detecting mutations in the cDNA and genomic DNA of the human p53 gene.     

甲胎蛋白胶体金检测试剂的的研制

为建立一种快速,简易胶体金免疫层析法（GICA）用于检测血清中的甲胎蛋白（AFP）,将AFP单克隆抗体分别标记胶体金并包被硝酸纤维素膜,制成免疫检测层析试剂,血清中的AFP与金标记抗体结合,沿着硝酸纤维素膜移动,与膜上的固相抗体结合可形成肉眼可见的紫红色线条,此检测试剂对本室自制AFP参比品进行了检测,灵敏度达20ng/ml;对甘肃省肿瘤医院的176份癌症患者血清进行了检测。结果与ELISA法相一致,本法检测AFP快速,简便,结果准确,具有推广价值。     

Fluorescent studies directed towards the location of abnormal epithelial cells in cervical smears

Cervical screening is concerned with the search for abnormal epithelial cells in smears prepared from scrapings from the uterine cervix. It is a highly skilled labour intensive operation and automated methods of detecting dyskariotic cells in cervical smears would be helpful. We report a fluorescence method of detecting abnormal cervical cells in smears and biopsies using a probe for guanidinobenzoatase. This approach has the potential for automation.     

Study of polymorphism in human rRNA gene clusters

Human ribosomal DNA (rDNA) probe specific for the 3' end of the 28S rRNA gene was used for detecting standard restriction fragments' length polymorphism (RFLPs) in the non-transcribed spacer. The conditions for hybridization of rDNA probe which eliminate cross hybridization of parts of 28S rRNA gene were developed. A test for detecting incompletely restricted DNA was also developed which may be used in experiments for detecting new RFLPs. It was found that a set of standard RFLPs was identical in various human tissues for one individual. Frequency of standard RFLPs in the non-transcribed spacer of human rRNA gene clusters was calculated.     

Comparative use of active searches and artificial refuges to detect amphibians in terrestrial environments

Artificial refuges (cover boards) are commonly used to survey and monitor herpetofauna in many parts of the world. Despite the extensive use of artificial refuges in mesic environments, their effectiveness for detecting amphibians in temperate zones has rarely been examined. We compared amphibian detection probabilities between two survey methods; active searches of natural habitat and artificial refuges of three different types (corrugated steel, roofing tiles and timber railway sleepers). Our study area included five bioregions encompassing a 1180‐km latitudinal gradient across a modified, temperate eucalypt woodland vegetation community in south‐eastern Australia. We deployed 14 778 artificial refuges in terrestrial environments, within patches of remnant vegetation, and collected presence and abundance data on herpetofauna between 1999 and 2017. We used Bayesian logistic regression to identify the most effective survey method for detecting frog species across all bioregions. We modelled frog detections by fitting survey method, time since refuge deployment and rainfall prior to each survey. We detected 3970 individuals from 18 frog species. Overall, we found active searches and timber substrates most effective for detecting a broad range of species, although detection rates were driven by the numerically abundant spotted marsh frog Limnodynastes tasmaniensis. Timber refuges were effective for detecting several burrowing species, whereas active searches were effective at detecting habitat generalists. Quadratic effects of rainfall prior to survey as opposed to linear effects of time since artificial refuge placement was important in explaining frog detection rates in some bioregions. Active searches, timber railway sleepers and sheets of corrugated steel provide complimentary survey methods for detecting amphibians, although detection rates are influenced by rainfall patterns. Artificial refuges provide a time‐effective and standardized method for studying amphibians in their non‐breeding terrestrial environment and should be incorporated into future surveys and biodiversity monitoring programmes.     

Repseek, a tool to retrieve approximate repeats from large DNA sequences

Chromosomes or other long DNA sequences contain many highly similar repeated sub-sequences. While there are efficient methods for detecting strict repeats or detecting already characterized repeats, there is no software available for detecting approximate repeats in large DNA sequences allowing for weighted substitutions and indels in a coherent statistical framework. Here, we present an implementation of a two-steps method (seed detection followed by their extension) that detects those approximate repeats. Our method is computationally efficient enough to handle large sequences and is flexible enough to account for influencing factors, such as sequence-composition biases both at the seed detection and alignment levels. AVAILABILITY: http://wwwabi.snv.jussieu.fr/public/RepSeek/     

Development and use of anchored‐SSRs to study DNA polymorphism in bread wheat (Triticum aestivum L.)

In bread wheat, 21 anchored simple sequence repeat (SSR) primer pairs detecting SSR length polymorphism and 42 anchored SSR primers detecting microsatellite‐anchored fragment length polymorphisms (MFLPs) are reported. Eight bread wheat genotypes were used for detecting polymorphism. The number of alleles in SSR analysis ranged from two to six, with a mean of 2.9 alleles per SSR. The number of polymorphic bands in MFLP ranged from two to 40, with a mean of 12.74 polymorphic bands/primer combination, the SSRs with CT/GA motifs giving the highest level of polymorphism (a mean of 18.37 bands). The average value of polymorphic information content (PIC) was 0.473 for SSRs and 0.061 for MFLP.     

基因结构变异检测方法综述

在人类基因组中结构变异(SVs),拷贝数变化(CNVs),单核苷酸多态性(SNP)是非常普遍的,而且和人类健康与疾病密切相关,因此检测这些结构变异对于人类生命健康非常重要。基于第二代基因测序平台,目前已经有很多结构变异检测算法,这些算法主要分为五大类:微阵列方法、读对方法、读深方法、分裂读取方法、序列组装方法。本文系统地阐述了这五类方法的基本原理、优缺点以及使用范围,并简要介绍了每一种方法的经典检测算法及应用范围、检测性能等,并对未来检测算法的研究提出了展望。     

原木形状分段描述方法的数学描述理论研究

为制材、木材检尺等特殊行业需要的原木数控检测提供数学描述理论,提出的这些理论将为数控检测的数学模型建立提供具体的数学方法,为原木形状的视频再现提供编程的数学工具．本文提出的理论还将为数控下锯法提供理论依据,与制材工艺结合起来,将使传统原木检测数字化,为科学管理原木和数字化统计与检尺控制提供了理论,本文是木材工业中用数学描述检测过程的开始．通过本文的研究,可以推进木材工业检测过程数学描述研究的开展．