Calcium Promotes T6SS-Mediated Killing and Aggregation between Competing Symbionts.
Calcium Promotes T6SS-Mediated Killing and Aggregation between Competing Symbionts.
复制标题
钙促进了竞争共生体之间的T6SS介导的杀戮和聚集。
DOI：
10.1128/spectrum.01397-22
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发表时间：
2022-12-21
影响因子：
3.7
通讯作者：
Septer, Alecia N.
中科院分区：
文献类型：
--
作者：
Speare, Lauren;Jackson, Aundre;Septer, Alecia N.
Bacteria use a variety of strategies to exclude competitors from accessing resources, including space within a host niche.由于这些机制的部署成本通常很高，因此在效益大于能源成本的环境中使用它们通常受到严格监管。 VI 型分泌系统 (T6SS) 是一种竞争机制，允许抑制剂通过物理刺穿细胞毒性效应物并将其直接转移到邻近的竞争细胞中来杀死竞争微生物。尽管 T6SS 在共生和自由生活的类群中都有编码，它们在液体培养物中生长期间可能会主动分泌到细胞外环境中，但几乎没有证据表明细菌在低粘度液体条件下参与 T6SS 介导的接触依赖性杀伤。在这里，我们确定钙作为 pH 依赖性线索来激活低粘度液体介质中费氏弧菌光器官共生体中抗菌 T6SS 的组装。此外，竞争性费氏弧菌分离株形成混合菌株聚集体，促进了 T6SS 依赖性消除目标群体所需的接触。我们的研究结果扩展了我们对 V. fischeri T6SS 生态学的了解，并确定了细胞进行接触依赖性杀伤的低粘度液体条件。 IMPORTANCE Microbes deploy competitive mechanisms to gain access to resources such as nutrients or space within an ecological niche. Identifying when and where these strategies are employed can be challenging given the complexity and variability of most natural systems;因此，评估有条件调节细菌间竞争的特定线索的研究可以为这种竞争的生态环境提供信息。在这项工作中，我们在海水中发现了一种依赖于 pH 值的化学信号——钙，它可以促进海洋共生体费氏弧菌中依赖于接触的细菌间武器的激活。这一发现强调了在生长培养基中使用生态相关盐的重要性以及细菌细胞感知和整合多种环境线索以评估武器需求的能力。对这些线索的识别可以深入了解使用武器有利于细菌种群生存和繁殖的环境类型。
Bacteria use a variety of strategies to exclude competitors from accessing resources, including space within a host niche. Because these mechanisms are typically costly to deploy, they are often tightly regulated for use in environments where the benefits outweigh the energetic cost. The type VI secretion system (T6SS) is a competitive mechanism that allows inhibitors to kill competing microbes by physically puncturing and translocating cytotoxic effectors directly into neighboring competitor cells. Although T6SSs are encoded in both symbiotic and free-living taxa where they may be actively secreting into the extracellular milieu during growth in liquid culture, there is little evidence for bacteria engaging in T6SS-mediated, contact-dependent killing under low-viscosity liquid conditions. Here, we determined that calcium acts as a pH-dependent cue to activate the assembly of an antibacterial T6SS in a Vibrio fischeri light organ symbiont in a low-viscosity liquid medium. Moreover, competing V. fischeri isolates formed mixed-strain aggregates that promoted the contact necessary for T6SS-dependent elimination of a target population. Our findings expand our knowledge of V. fischeri T6SS ecology and identify a low-viscosity liquid condition where cells engage in contact-dependent killing. IMPORTANCE Microbes deploy competitive mechanisms to gain access to resources such as nutrients or space within an ecological niche. Identifying when and where these strategies are employed can be challenging given the complexity and variability of most natural systems; therefore, studies evaluating specific cues that conditionally regulate interbacterial competition can inform the ecological context for such competition. In this work, we identified a pH-dependent chemical cue in seawater, calcium, which promotes activation of a contact-dependent interbacterial weapon in the marine symbiont Vibrio fischeri. This finding underscores the importance of using ecologically relevant salts in growth media and the ability of bacterial cells to sense and integrate multiple environmental cues to assess the need for a weapon. Identification of these cues provides insight into the types of environments where employing a weapon is advantageous to the survival and propagation of a bacterial population.
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DOI：
10.1073/pnas.1808302115
发表时间：
2018-09-04
影响因子：
11.1
作者：
Speare L;Cecere AG;Guckes KR;Smith S;Wollenberg MS;Mandel MJ;Miyashiro T;Septer AN
通讯作者：
Septer AN
由具有内在细胞进入特性的 T6SS 效应器介导的不依赖于接触的杀伤
影响因子：
16.6
作者：
Song L;Pan J;Yang Y;Zhang Z;Cui R;Jia S;Wang Z;Yang C;Xu L;Dong TG;Wang Y;Shen X
通讯作者：
Shen X
影响因子：
3.2
作者：
Tischler, Alice H.;Lie, Louise;Visick, Karen L.
通讯作者：
Visick, Karen L.
影响因子：
3.7
作者：
Salomon D;Gonzalez H;Updegraff BL;Orth K
通讯作者：
Orth K
影响因子：
3.2
作者：
Murdoch, Sarah L.;Trunk, Katharina;Coulthurst, Sarah J.
通讯作者：
Coulthurst, Sarah J.