| Bacterial Conjugation Protocol for Ruminant Mycoplasmas
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Author:
Date:
2021-01-20
[Abstract] In Mycoplasma agalactiae, two simultaneous processes of DNA transfer have been described that require direct cell-to-cell contact and are similar to conjugation. One involves the self-transmission of an integrative conjugative element (ICE) while the second concerns the horizontal transfer of large and small fragments of chromosomal DNA. Here, we describe an optimized conjugation protocol for the horizontal transfer of ICE or chromosomal DNA carrying antibiotic resistance markers (i.e., tetracycline, gentamicin, puromycin) from donor to recipient mycoplasma cells. Calculation of the conjugation frequencies, selection and characterization of transconjugants are detailed. This protocol has been developed with M. agalactiae but has been successfully used for M. bovis and can be adapted to ...
[摘要] [摘要]在无乳支原体中，已经描述了DNA转移的两个同时过程，它们需要直接的细胞间接触，并且类似于缀合。一种涉及整合共轭元件（ICE）的自我传递，而第二种涉及染色体DNA大小片段的水平转移。在这里，我们描述了一种优化的结合方案，用于从供体到受体支原体细胞水平转移带有抗生素抗性标记（即四环素，庆大霉素，嘌呤霉素）的ICE或染色体DNA 。详细介绍了共轭频率的计算，跨共轭物的选择和表征。该协议已与无乳分枝杆菌一起开发但已成功用于牛分枝杆菌，并可适应其他相关支原体物种。
[背景]共轭的，水平的DNA转移是微生物多样化的关键角色。通过促进细胞与细胞之间的紧密接触主动转移DNA （Lederberg和Tatum，1946），这种现象促进了从外部资源快速获取新性状。支原体（类柔膜）是无壁菌，其进化已经被认为是由基因损失仅减小驱动的基因组，并且其中水平基因转移（HGT ）被长期被认为是边缘。在过去的十年中，比较基因组学分析重新审视了这种范例，并显示出（i）在共享同一宿主的支原体物种之间发生了HGTs事件（Sirand-Pugnet et al。，2007），以及（ii）整合和共轭的存在元件（ICE中）中的大量测序支原体基因组（Calcutt等人，2002; Marenda等人，2006; Dordet-弗里索尼等人，2013;拖期等人，2015; Meygret ...
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| In vivo Blood-brain Barrier Permeability Assays Using Clostridium perfringens Epsilon Toxin
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Author:
Date:
2020-08-05
[Abstract] In order for the brain to function properly, a carefully orchestrated homeostasis must be maintained. To help regulate this delicate balance, the brain has developed a highly selective blood-brain barrier (BBB). Under normal conditions, the BBB excludes harmful blood-borne material from the brain parenchyma. However, numerous neuropathological conditions can disrupt this barrier, causing BBB permeability and subsequent CNS dysfunction. Understanding the mechanisms involved in BBB permeability are essential to elucidating the pathology of various neurological disorders as well as identifying methods for drug delivery to the CNS. Here, we describe several in vivo methods to measure BBB permeability in mice using an array of diverse sized tracers including exogenous 376 Da ...
[摘要] [摘要]为了使大脑正常工作，必须维持精心安排的体内平衡。为了帮助调节这种微妙的平衡，大脑已经形成了一种高度选择性的血脑屏障（BBB）。在正常情况下，血脑屏障将有害的血液传播物质排除在脑实质之外。然而，许多神经病理学条件可以破坏这一屏障，导致BBB通透性和随后的CNS功能障碍。了解BBB通透性的机制对于阐明各种神经系统疾病的病理学以及确定药物输送到中枢神经系统的方法至关重要。在这里，我们描述了几种在体内使用不同大小的示踪剂（包括外源性376da荧光素盐、66.5kDa牛血清白蛋白、70kDa右旋糖酐以及内源性160kDa小鼠IgG）来测量BBB在小鼠体内的通透性。当静脉注射时，这些物质会被BBB排除在健康大脑之外。然而，BBB功能障碍可使这些示踪剂进入大脑，这种积聚可通过分光光度法、荧光显微镜和免疫组织化学进行测量。我们还描述了一种利用产气荚膜梭菌epsilon毒素诱导BBB通透性的方法。最后，我们将简要讨论每种方法的优缺点及其适当的下游应用。
[背景] ...
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| Adapting the Smart-seq2 Protocol for Robust Single Worm RNA-seq
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Author:
Date:
2018-02-20
[Abstract] Most nematodes are small worms that lack enough RNA for regular RNA-seq protocols without pooling hundred to thousand of individuals. We have adapted the Smart-seq2 protocol in order to sequence the transcriptome of an individual worm. While developed for individual Steinernema carpocapsae and Caenorhabditis elegans larvae as well as embryos, the protocol should be adaptable for other nematode species and small invertebrates. In addition, we describe how to analyze the RNA-seq results using the Galaxy online environment. We expect that this method will be useful for the studying gene expression variances of individual nematodes in wild type and mutant backgrounds.
[摘要] 大多数线虫是小蠕虫，缺乏足够的RNA用于常规的RNA-seq协议，而没有汇集成千上万的个体。 我们已经调整了Smart-seq2协议来排序单个蠕虫的转录组。 虽然针对Steinernema carpocapsae和Caenorhabditis elegans幼虫以及胚胎开发，但该方案应该适用于其他线虫物种和小无脊椎动物。 另外，我们介绍如何使用Galaxy在线环境分析RNA-seq结果。 我们预计这种方法将有助于研究野生型和突变体背景个体线虫的基因表达差异。
【背景】低输入RNA-seq方案和扩增试剂盒，例如Smart-seq（Takara Bio，USA，Inc）和SuperAmp（Miltenyl Biotec，Inc），已经越来越多地开发和商业化，作为对低输入RNA-基于小组织，单一微生物和单细胞的seq研究。这些研究经常探索并解决特定群体（例如细胞群体，复杂组织或微生物群体）的个体中的异源基因表达。针对微生物（如线虫）的低输入RNA-seq方案的改进和适应将通过允许在单一线虫水平上分析基因表达异质性而极大地有益于线虫领域。在这里，我们已经调整了单细胞RNA-seq方案Smart-seq2（Picelli等人，2013和2014; Trombetta等人，2014），对于单线虫RNA测序。我们成功地在昆虫寄生线虫Steinernema ...
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