The Burkholderia bcpAIOB genes define unique classes of two-partner secretion and contact dependent growth inhibition systems.
The Burkholderia bcpAIOB genes define unique classes of two-partner secretion and contact dependent growth inhibition systems.
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DOI：
10.1371/journal.pgen.1002877
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发表时间：
2012
期刊：
影响因子：
4.5
通讯作者：
Cotter PA
中科院分区：
文献类型：
--
作者：
Anderson MS;Garcia EC;Cotter PA
微生物进化出许多策略来适应环境条件和种群结构的变化，包括合作和竞争。一种明显的竞争机制是接触依赖性生长抑制（CDI）。在大肠杆菌中鉴定，CDI由双伴侣分泌（TPS）途径蛋白质CdiA和CdiB介导。在细胞接触时，TpsA家族成员CdiA的毒性C-末端，称为CdiA-CT，抑制CDI−细菌的生长。CDI+细菌通过免疫蛋白CdiI保护免于自身抑制。生物信息学分析表明，CDI系统广泛存在于α、β和γ变形菌中，并且CdiA-CT和CdiI蛋白高度可变。CDII蛋白以等位基因特异性方式保护免受CDI。在这里，我们在伯克霍尔德氏菌、罗尔斯通氏菌和贪铜菌物种中鉴定了预测的CDI系统编码基因座，命名为bcpAIOB，其与之前描述的CDI系统的区别在于基因顺序和位于编码基因5 '端的小ORF bcpO的存在。TpsB家族成员。证明了BcpA（TpsA家族成员）功能中对bcpO的需求，表明bcpAIOB定义了一类新的TPS系统。使用荧光显微镜和流式细胞仪，我们表明，这些基因表达的概率方式在液体培养基中培养的伯克霍尔德氏菌泰国。bcpA 10 B基因和细胞外DNA是自动聚集和粘附到非生物表面所需的，表明CDI是生物膜形成所需的，这是先前不归因于CDI的活性。与E. coli、B. B. thailandensis bcpAIOB基因仅介导固体表面上的细菌间竞争。竞争发生在一个确定的时空方式，并废除等位基因特异性免疫。我们的数据表明，bcpAIOB基因编码不同类别的CDI和TPS系统，似乎在社会微生物群落的发展中发挥作用。接触依赖性生长抑制（CDI）是在大肠杆菌中发现的一种现象，其中CDI+细菌在细胞与细胞接触时抑制CDI−细菌的生长。CDI由存在于细菌细胞表面上的大的毒性“外蛋白”介导。一种“免疫”蛋白可以保护CDI+细胞不杀死自己。虽然预测的CDI系统在细菌属中广泛存在，但这些系统在自然界中的作用仍然难以捉摸。在这里，我们确定了一个独特的类的CDI系统在伯克霍尔德氏菌属物种。编码这些系统的基因以随机方式表达，使得当在肉汤中生长时，群体中只有少数细胞在任何给定时间产生蛋白质。我们还表明，这些系统所需的非生物表面上的聚集，这表明CDI在生物膜形成的重要作用。最后，我们表明，CDI介导的竞争在特定条件下，在一个精确的时空模式，当细菌生长在固体表面上。我们的数据表明，在自然界中，CDI系统可能被细菌用来建立复杂的社会微生物群落。
Microbes have evolved many strategies to adapt to changes in environmental conditions and population structures, including cooperation and competition. One apparently competitive mechanism is contact dependent growth inhibition (CDI). Identified in Escherichia coli, CDI is mediated by Two–Partner Secretion (TPS) pathway proteins, CdiA and CdiB. Upon cell contact, the toxic C-terminus of the TpsA family member CdiA, called the CdiA-CT, inhibits the growth of CDI− bacteria. CDI+ bacteria are protected from autoinhibition by an immunity protein, CdiI. Bioinformatic analyses indicate that CDI systems are widespread amongst α, β, and γ proteobacteria and that the CdiA-CTs and CdiI proteins are highly variable. CdiI proteins protect against CDI in an allele-specific manner. Here we identify predicted CDI system-encoding loci in species of Burkholderia, Ralstonia and Cupriavidus, named bcpAIOB, that are distinguished from previously-described CDI systems by gene order and the presence of a small ORF, bcpO, located 5′ to the gene encoding the TpsB family member. A requirement for bcpO in function of BcpA (the TpsA family member) was demonstrated, indicating that bcpAIOB define a novel class of TPS system. Using fluorescence microscopy and flow cytometry, we show that these genes are expressed in a probabilistic manner during culture of Burkholderia thailandensis in liquid medium. The bcpAIOB genes and extracellular DNA were required for autoaggregation and adherence to an abiotic surface, suggesting that CDI is required for biofilm formation, an activity not previously attributed to CDI. By contrast to what has been observed in E. coli, the B. thailandensis bcpAIOB genes only mediated interbacterial competition on a solid surface. Competition occurred in a defined spatiotemporal manner and was abrogated by allele-specific immunity. Our data indicate that the bcpAIOB genes encode distinct classes of CDI and TPS systems that appear to function in sociomicrobiological community development. Contact dependent growth inhibition (CDI) is a phenomenon discovered in Escherichia coli in which CDI+ bacteria inhibit the growth of CDI− bacteria upon cell-to-cell contact. CDI is mediated by large toxic “exoproteins” present on the bacterial cell surface. An ‘immunity’ protein protects CDI+ cells from killing themselves. While predicted CDI systems are widespread throughout bacterial genera, the role of these systems in nature has remained elusive. Here we identify a distinct class of CDI system in Burkholderia species. The genes encoding these systems are expressed in a stochastic manner such that only a few cells in the population produce the proteins at any given time when grown in broth. We also show that these systems are required for aggregation on an abiotic surface, suggesting an important role for CDI in biofilm formation. Finally, we show that CDI mediates competition under specific conditions in a precise spatiotemporal pattern when bacteria are grown on a solid surface. Our data suggest that in nature, CDI systems may be used by bacteria to establish complex sociomicrobial communities.
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影响因子：
64.8
作者：
通讯作者：
--
DOI：
10.1099/00207713-48-1-317
发表时间：
1998-01-01
期刊：
INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY
影响因子：
--
作者：
Brett, PJ;DeShazer, D;Woods, DE
通讯作者：
Woods, DE
影响因子：
3.2
作者：
JacobDubuisson, F;Buisine, C;Locht, C
通讯作者：
Locht, C
DOI：
10.1073/pnas.0831229100
发表时间：
2003-04-29
影响因子：
11.1
作者：
Dupin, E;Real, C;Le Douarin, NM
通讯作者：
Le Douarin, NM
影响因子：
2.7
作者：
Currie, BJ;Fisher, DA;Mayo, MJ
通讯作者：
Mayo, MJ