| Bacterial Competition Assay Based on Extracellular D-amino Acid Production
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Author:
Date:
2018-04-05
[Abstract] Bacteria live in polymicrobial communities under tough competition. To persist in a specific niche many species produce toxic extracellular effectors as a strategy to interfere with the growth of nearby microbes. One of such effectors are the non-canonical D-amino acids. Here we describe a method to test the effect of D-amino acid production in fitness/survival of bacterial subpopulations within a community. Co-cultivation methods usually involve the growth of the competing bacteria in the same container. Therefore, within such mixed cultures the effect on growth caused by extracellular metabolites cannot be distinguished from direct physical interactions between species (e.g., T6SS effectors). However, this problem can be easily solved by using a filtration unit that allows free ...
[摘要] 在激烈的竞争中，细菌生活在多种微生物群落中。为了坚持特定的生态位，许多物种会产生有毒的细胞外效应物作为干扰附近微生物生长的策略。这种效应子之一是非规范的D-氨基酸。在这里我们描述一种方法来测试D-氨基酸生产对社区内细菌亚群的适应/存活的影响。共培养方法通常涉及相同容器中竞争细菌的生长。因此，在这种混合培养物中，细胞外代谢物对生长的影响不能与物种间的直接物理相互作用区分开（例如T6SS效应物）。然而，通过使用允许小分解代谢物（例如L-和D-氨基酸）自由扩散的过滤单元可以容易地解决这个问题，同时将不同亚群保持在独立区室中。
通过这种方法，我们已经证明D-精氨酸是由霍乱弧菌产生的杀菌剂效应物，其强烈影响不同微生物亚群的存活。此外，D-精氨酸可作为混合菌群中的一种协同工具，用于保护非生产成员免受竞争细菌的侵害。
【背景】细菌生活在多种多样的物种共存并争夺现有资源的多种微生物群落中。细菌设计为在特定生态位持续存在的许多策略之一是产生有毒的细胞外代谢物作为干扰其他微生物生长和/或生存力的策略。已知D-氨基酸长时间在细菌培养物中具有细胞形状和活力的强大作用（Bopp，1965; Fox等人，1944; Kobayashi等人， 1948年; Yaw和Kakavas，1952年; Lark和Lark，1959年; Grula，1960年; ...
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| ER Microsome Preparation and Subsequent IAA Quantification in Maize Coleoptile and Primary Root Tissue
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Author:
Date:
2016-05-05
[Abstract] Auxin is a major growth hormone in plants and the first plant hormone to be discovered and studied (Darwin and Darwin, 1880). The auxin molecule in plants was first identified as indole-3-acetic acid (IAA) by Kögl et al. (1934). Active research over nearly a decade has shed light on many of the molecular mechanisms of its action but the complexity and redundancy of the auxin biosynthetic network raises questions about control of this system. We have shown that some enzymes involved in the YUCCA-route of auxin biosynthesis are not cytosolic but localised to the endoplasmic reticulum (ER) in both Arabidopsis thaliana (YUCCA4.2) (Kriechbaumer et al., 2012) as well as Zea mays (ZmTAR1 and ZmSPI) (Kriechbaumer et al., 2015). This ...
[摘要] 生长素是植物中的主要生长激素和待发现和研究的第一种植物激素（Darwin和Darwin，1880）。植物中的植物生长素分子首先由Kögl等人确定为吲哚-3-乙酸（IAA）。 （1934）。近十年的积极研究揭示了其作用的许多分子机制，但是生长素生物合成网络的复杂性和冗余性提出了对该系统的控制的问题。我们已经显示，参与植物生长素生物合成的YUCCA途径的一些酶不是细胞质的，而是定位于拟南芥中的内质网（ER）（YUCCA4.2）（Kriechbaumer等人。（ Zm TAR1和 Zm SPI）（Kriechbaumer /em>，2015）。这提高了生长素生物合成的亚细胞区室的有趣的可能性。为了显示玉米生长素生物合成确实可以在来自玉米幼苗的微粒体以及胞质细胞部分中发生，我们应用本文所述的方案：从玉米胚芽鞘和原代根组织分离微粒体，使用色氨酸的微粒体和胞浆部分的酶测定（Trp）或吲哚-3-丙酮酸（IPyA）作为底物，并提取并定量生长素IAA。
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| Isolation of Tomato Fruit Chromoplasts and Determination of ATP Levels
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Author:
Date:
2014-08-05
[Abstract] It has recently been reported that tomato fruit chromoplasts can synthesize ATP de novo using an ATP synthase complex harboring an atypical γ-subunit which is also present in a variety of plant species. However many aspects related with the biochemical processes underlying this process remain largely unknown. Here we describe detailed protocols for the isolation of tomato fruit chromoplasts and the determination of ATP levels (end-point measurements) and ATP synthesis rates (kinetic measurements) in these organelles using bioluminescent luciferin/luciferase based assays.
[摘要] 最近报道了番茄果实色素可以使用含有非典型γ亚基的ATP合酶复合物来合成ATP，所述亚基也存在于多种植物物种中。 然而，与这个过程基础的生化过程相关的许多方面仍然很大程度上未知。 在这里我们描述了隔离番茄果实色质体和ATP水平（终点测量）和ATP合成率（动力学测量）在这些细胞器中使用基于生物发光荧光素/荧光素酶的测定的确定详细协议。
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