DNA Restriction Enzymes

DNA 限制性酶
  • 文章类型: Journal Article
    Determining phylogenetic relationships among recently diverged species has long been a challenge in evolutionary biology. Cytoplasmic DNA markers, which have been widely used, notably in the context of molecular barcoding, have not always proved successful in resolving such phylogenies. However, with the advent of next-generation-sequencing technologies and associated techniques of reduced genome representation, phylogenies of closely related species have been resolved at a much higher detail in the last couple of years. Here we examine the potential and limitations of one of such techniques-Restriction-site Associated DNA (RAD) sequencing, a method that produces thousands of (mostly) anonymous nuclear markers, in disentangling the phylogeny of the fly genus Chiastocheta (Diptera: Anthomyiidae). In Europe, this genus encompasses seven species of seed predators, which have been widely studied in the context of their ecological and evolutionary interactions with the plant Trollius europaeus (Ranunculaceae). So far, phylogenetic analyses using mitochondrial markers failed to resolve monophyly of most of the species from this recently diversified genus, suggesting that their taxonomy may need a revision. However, relying on a single, non-recombining marker and ignoring potential incongruences between mitochondrial and nuclear loci may provide an incomplete account of the lineage history. In this study, we applied both classical Sanger sequencing of three mtDNA regions and RAD-sequencing, for reconstructing the phylogeny of the genus. Contrasting with results based on mitochondrial markers, RAD-sequencing analyses retrieved the monophyly of all seven species, in agreement with the morphological species assignment. We found robust nuclear-based species assignment of individual samples, and low levels of estimated contemporary gene flow among them. However, despite recovering species\' monophyly, interspecific relationships varied depending on the set of RAD loci considered, producing contradictory topologies. Moreover, coalescence-based phylogenetic analyses revealed low supports for most of the interspecific relationships. Our results indicate that despite the higher performance of RAD-sequencing in terms of species trees resolution compared to cytoplasmic markers, reconstructing inter-specific relationships among recently-diverged lineages may lie beyond the possibilities offered by large sets of RAD-sequencing markers in cases of strong gene tree incongruence.
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    文章类型: Journal Article
    The bacteriophage ΦAb-Sp7 was isolated from the cells of the Azospirillum brasilense Sp7. The morphology, size of the gram-negative colonies, and range of lytic activity against other strains and species of the genus Azospirillum was tested. The isolated phage DNA was examined using electrophoretic and restriction analysis, and the size of the genome were established. The electron microscopy. resuIts show that the phage (capsid) has a strand-like form. The electron microscopy study of the bacteriophage ΦAb-Sp7 adsorption on the A. brasilense Sp7 bacterial surface was performed.
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  • 文章类型: Journal Article
    Wetlands are important sources of the greenhouse gas methane (CH4). We provide an in situ study of CH4 dynamics in the permanently submerged soil of a Swiss alpine fen. Physico-chemical pore water analyses were combined with structural and microbiological analyses of soil cores at high vertical resolution down to 50 cm depth. Methanotrophs and methanogens were active throughout the depth profile, and highest abundance of active methanotrophs and methanogens [6.1 × 10(5) and 1.1 × 10(7) pmoA and mcrA transcripts (g soil)(-1), respectively] was detected in the uppermost 2 cm of the soil. Active methanotrophic communities in the near-surface zone, dominated by viable mosses, varied from the communities in the deeper zones, but further changes with depth were not pronounced. Apart from a distinct active methanogenic community in the uppermost sample, a decrease of acetoclastic Methanosaetaceae with depth was observed in concomitance with decreasing root surface area. Overall, root surface area correlated with mcrA transcript abundance and CH4 pore water concentrations, which peaked (137.1 μM) at 10 to 15 cm depth. Our results suggest that stimulation of methanogenesis by root exudates of vascular plants had a stronger influence on CH4 dynamics than stimulation of CH4 oxidation by O2 input.
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  • 文章类型: Journal Article
    The cholesteryl ester transfer protein (CETP) plays a crucial role in high-density lipoprotein (HDL) metabolism. Genetic variants that alter CETP concentration may cause significant alterations in HDL-cholesterol (HDL-C) concentration. In this case-control study, we analyzed the genotype frequencies of CETP Taq1B polymorphisms in coronary artery disease patients (CAD; n=210) and controls (n=100). We analyzed the role of the CETP Taq1B variant in severity of CAD, and its association with plasma lipids and CETP concentration. DNA was extracted from 310 patients undergoing coronary angiography. The Taq1B polymorphism was genotyped using polymerase chain reaction-restriction fragment length polymorphism (RFLP) analysis. Lipid concentrations were measured by an auto analyzer and CETP level by a commercial enzyme-linked immunosorbent assay (ELISA) kit. In our study population, the B2 allele frequency was higher in control subjects than patients with single, double or triple vessel disease. B2B2 genotype carriers had a significantly higher high-density lipoprotein cholesterol (HDL-C) concentration than those with the B1B1 genotype in controls (51.93±9.47versus 45.34±9.93; p<0.05) and in CAD patients (45.52±10.81 versus 40.38±9.12; p<0.05). B2B2 genotype carriers had a significantly lower CETP concentration than those with the B1B1 genotype in controls (1.39±0.58 versus 1.88±0.83; p< 0.05) and in CAD patients (2.04±1.39versus 2.81±1.68; p< 0.05). Our data suggest that the B2 allele is associated with higher concentrations of HDL-C and lower concentrations of CETP, which confer a protective effect on coronary artery disease.
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  • 文章类型: Journal Article
    血糖控制受损和过度肥胖是2型糖尿病的主要危险因素。在啮齿动物模型中,Ad36,一种人腺病毒,改善血糖控制,与膳食脂肪摄入量或肥胖无关。使用Ad36进行治疗作用是不切实际的。相反,我们发现Ad36的E4orf1蛋白介导其抗高血糖作用,不依赖于胰岛素信号传导.为了进一步评估E4orf1改善血糖控制的治疗潜力,我们建立了一个稳定的3T3-L1细胞系统,其中可以调节E4orf1的表达。本文描述了该细胞系的发展和表征。将通过PCR获得的全长腺病毒36E4orf1cDNA克隆到含有四环素应答元件的载体(pTRE-Tight-E4orf1)中。在筛选了数十个pTRE-Tight-E4orf1克隆后,我们确定了响应多西环素治疗的E4orf1表达最高的一种。此外,使用这种可诱导系统,我们表征了E4orf1以时间依赖性方式改善葡萄糖处理的能力。这种稳定的细胞系为仔细研究E4orf1用于增强独立于胰岛素的细胞葡萄糖处置的新信号通路提供了宝贵的资源。
    Impaired glycemic control and excessive adiposity are major risk factors for Type 2 Diabetes mellitus. In rodent models, Ad36, a human adenovirus, improves glycemic control, independent of dietary fat intake or adiposity. It is impractical to use Ad36 for therapeutic action. Instead, we identified that E4orf1 protein of Ad36, mediates its anti-hyperglycemic action independent of insulin signaling. To further evaluate the therapeutic potential of E4orf1 to improve glycemic control, we established a stable 3T3-L1 cell system in which E4orf1 expression can be regulated. The development and characterization of this cell line is described here. Full-length adenoviral-36 E4orf1 cDNA obtained by PCR was cloned into a tetracycline responsive element containing vector (pTRE-Tight-E4orf1). Upon screening dozens of pTRE-Tight-E4orf1 clones, we identified the one with the highest expression of E4orf1 in response to doxycycline treatment. Furthermore, using this inducible system we characterized the ability of E4orf1 to improve glucose disposal in a time dependent manner. This stable cell line offers a valuable resource to carefully study the novel signaling pathways E4orf1 uses to enhance cellular glucose disposal independent of insulin.
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  • 文章类型: Journal Article
    The detection of semen can assist in reconstructing the events of a sexual assault and impact the outcome of legal dispositions. Many methods currently are used for detecting the presence of semen, but they all have limitations with regards to specificity, sample degradation/consumption, stability of biomolecule assayed, and/or incompatibility with downstream individual identification assays. DNA is routinely collected at sexual assault crime scenes and is widely used for individual identification. The DNA also carries methylation patterns that are tissue specific. To date, however, assays designed to exploit methylation patterns suffer from complex chemistries and unwieldy analyses. DSI-Semen™ kit uses a novel approach involving CpG methylation-sensitive restriction endonuclease digestion coupled to a multiplexed polymerase chain reaction (PCR) to generate an amplicon profile that makes it possible to determine whether the tissue source of a DNA sample was semen or non-semen. The assay returned an appropriate positive result for semen with neat semen, semen stains, and semen/non-semen tissue mixtures. The assay is robust and reliable, with a positive result for semen given as little as 31 pg of template DNA input. Low levels of semen were detected in mixtures of semen and other body fluids. UV-exposed samples and those in the presence of limited concentrations of known PCR inhibitors were typeable. The DSI-Semen™ kit provides a reliable tool for the determination of DNA being derived from semen.
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  • 文章类型: Journal Article
    The DNA fragment detection focusing technique has further enhanced the sensitivity and information of DNA targets. The DNA fragment detection method was established by capillary electrophoresis with laser-induced fluorescence detection and restriction endonuclease chromatographic fingerprinting (CE-LIF-REF) in our experiment. The silica capillary column was coated with short linear polyarclarylamide (SLPA) using nongel sieving technology. The excision product of various restricted enzymes of DNA fragments was obtained by REF with the molecular biology software Primer Premier 5. The PBR322/BsuRI DNA marker was used to establish the optimization method. The markers were focused electrophoretically and detected by CE-LIF. The results demonstrate that the CE-LIF-REF with SLPA can improve separation, sensitivity and speed of analysis. This technique may be applied to analysis of the excision product of various restricted enzymes of prokaryotic plasmid (pIRES2), eukaryote plasmid (pcDNA3.1) and the PCR product of codon 248 region of gastric cancer tissue. The results suggest that this method could very sensitively separate the excision products of various restricted enzymes at a much better resolution than the traditional agarose electrophoresis.
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  • 文章类型: Journal Article
    目的:色杆菌是引起高度致命的机会性感染的腐生菌。进行鉴定和菌株分化以鉴定环境样品之间的菌株变异性。我们已经评估了单独和组合方法的适用性,以检测在不同季节收集的样品的应变变化。
    结果:使用四种不同的限制性内切酶消化(AluI,海三世,MspI和RsaI)和五个随机引物。计算骰子相似性系数矩阵,并将其用于比较这些限制模式。ARDRA显示基于16SrDNA的菌株快速分化,但是RAPD和ARDRA的组合比单独分析两者中的任一种时提供了更可靠的区分。
    结论:观察到高水平的遗传多样性,这表明KolliHills\‘C.violaceum分离株将落入至少三个新的簇。
    结论:结果表明,在未开发的紫菜中,紫菜的细菌变异和遗传多样性值得注意,原始森林地区。
    OBJECTIVE: Chromobacterium are saprophytes that cause highly fatal opportunistic infections. Identification and strain differentiation were performed to identify the strain variability among the environmental samples. We have evaluated the suitability of individual and combined methods to detect the strain variations of the samples collected in different seasons.
    RESULTS: Amplified ribosomal DNA restriction analysis (ARDRA) and random amplified polymorphic DNA (RAPD) profiles were obtained using four different restriction enzyme digestions (AluI, HaeIII, MspI and RsaI) and five random primers. A matrix of dice similarity coefficients was calculated and used to compare these restriction patterns. ARDRA showed rapid differentiation of strains based on 16S rDNA, but the combined RAPD and ARDRA gave a more reliable differentiation than when either of them was analysed individually.
    CONCLUSIONS: A high level of genetic diversity was observed, which indicates that the Kolli Hills\' C. violaceum isolates would fall into at least three new clusters.
    CONCLUSIONS: Results showed a noteworthy bacterial variation and genetic diversity of C. violaceum in the unexplored, virgin forest area.
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  • DOI:
    文章类型: English Abstract
    OBJECTIVE: To create and evaluate the PCR restriction fragment length polymorphism (PCR-RFLP) based on hsp65 gene as a method for rapid identification of Mycobacteria to the species level.
    METHODS: hsp65 gene was amplified from the DNA of mycobacterial reference strains and the PCR products were subjected to digestion by two restriction endonucleases Hae III and Bstp I, then loaded onto a 4% MetaPhor agorose. The size of the restricted fragments of each species (strains) was determined according to the position of the fragments on the gel, by which the differential DNA fingerprint was confirmed.
    RESULTS: A total of 40 Mycobacterium species (strains) was analyzed, in which six reference strains of Mycobacterium tuberculosis Complex had two different electrophoresis patterns, and thirty-four reference species of non-tuberculosis Mycobacteria had unique pattern.
    CONCLUSIONS: PCR-RFLP Based upon hsp65 gene can be used for identification of Mycobacterium species, and the method is more rapid and simple and easy-to-use for mycobacterial species identification.
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  • 文章类型: Journal Article
    Low levels of plasma vitamin D have been implicated as a possible risk factor for both prostate cancer incidence and advanced disease, and recent phase II trials suggest that vitamin D supplementation might delay progression of prostate cancer. Common polymorphisms in the vitamin D receptor (VDR) are associated with VDR activity and are therefore potentially useful proxies for assessing whether vitamin D is causally related to advanced prostate cancer. We genotyped five well-known VDR polymorphisms in 1,604 men with prostate cancer from the Prostate Testing for Cancer and Treatment study. Our aim was to examine the association between VDR polymorphisms and cancer stage (localized versus advanced) as well as cancer grade (Gleason score <7 versus >or=7). Moreover, we also carried out a systematic review and meta-analysis of 13 similar studies. As a result of our meta-analysis, we revealed three polymorphisms, BsmI, ApaI, and TaqI, associated with high Gleason score with an overall summary odds ratios (95% confidence intervals) of 1.12 (1.00-1.25; bb versus BB + Bb), 1.25 (1.02-1.53; aa versus AA + Aa), and 0.82 (0.69-0.98; Tt + tt versus TT), respectively. The haplotype analysis revealed that the BsmI (B)-ApaI (A)-TaqI (t) participants compared with BsmI (b)-ApaI (a)-TaqI (T) individuals were less likely to have high Gleason scores (odds ratio, 0.84; 95% confidence interval, 0.71-1.00; P(unadjusted) = 0.050; P(adjusted) = 0.014). Our finding provides some support for the hypothesis that low levels of vitamin D may increase the risk of prostate cancer progression.
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