Diversity of Free-Living Environmental Bacteria and Their Interactions With a Bactivorous Amoeba
Diversity of Free-Living Environmental Bacteria and Their Interactions With a Bactivorous Amoeba
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DOI：
10.3389/fcimb.2018.00411
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发表时间：
2018-11-23
影响因子：
5.7
通讯作者：
Strassmann, Joan E.
中科院分区：
文献类型：
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作者：
Brock, Debra A.;Haselkorn, Tamara S.;Strassmann, Joan E.
土壤中的一小部分细菌直接与真核生物相互作用。哪一个这样做可以揭示什么是重要的真核生物和真核生物的防御可能被突破。土壤变形虫是简单的真核生物，因此对于理解真核生物微生物组如何起源和维持特别有用。其中一种变形虫，盘状网柄阿米巴，与细菌有永久和暂时的联系。在这里，我们专注于可培养的细菌联营公司，以询问他们的关系与D。盘状突为此，我们分离出了250多个D。从山湖生物站的土壤和鹿粪中采集的discoideum子实体样品。野生D.在我们测试的盘状孢囊群中，每个子实体孢子囊群（孢子团）发现1至6个细菌物种，总共174个细菌分离物。其余三分之二的D。discoideum子实体样品不包含可培养的细菌，这被认为是正常的。大多数（71.4%）独特的细菌单倍型是在变形菌。其余的是放线菌门、拟杆菌门或厚壁菌门。D.结果表明，来自鹿粪的盘状子实体数量（27个OTU）大于来自浅层土壤（11个OTU）和深层土壤（4个OTU）的数量。物种丰富度的稀疏曲线和Chao1估计表明，在任何衬底的多样性没有完全采样，但土壤，它接近。大多数D.盘菌相关细菌可被D.盘状幼体对粪便和土壤生境的支持率分别为75.2%和81.8%。然而，我们发现一些细菌属能够逃避吞噬，并坚持在D。通过一个或多个社会周期。本研究的重点不是整个D。discoideum微生物组，但对具有重要的真核生物相互作用作为猎物，共生体或病原体的细菌的可培养子集。这些真核生物和细菌的相互作用可能提供肥沃的土壤，为调查细菌使用变形虫获得初步的立足点，在真核生物和共生和简单的微生物的起源。
A small subset of bacteria in soil interact directly with eukaryotes. Which ones do so can reveal what is important to a eukaryote and how eukaryote defenses might be breached. Soil amoebae are simple eukaryotic organisms and as such could be particularly good for understanding how eukaryote microbiomes originate and are maintained. One such amoeba, Dictyostelium discoideum, has both permanent and temporary associations with bacteria. Here we focus on culturable bacterial associates in order to interrogate their relationship with D. discoideum. To do this, we isolated over 250 D. discoideum fruiting body samples from soil and deer feces at Mountain Lake Biological Station. In one-third of the wild D. discoideum we tested, one to six bacterial species were found per fruiting body sorus (spore mass) for a total of 174 bacterial isolates. The remaining two-thirds of D. discoideum fruiting body samples did not contain culturable bacteria, as is thought to be the norm. A majority (71.4%) of the unique bacterial haplotypes are in Proteobacteria. The rest are in either Actinobacteria, Bacteriodetes, or Firmicutes. The highest bacterial diversity was found in D. discoideumfruiting bodies originating fromdeer feces (27 OTUs), greater than either of those originating in shallow (11 OTUs) or in deep soil (4 OTUs). Rarefaction curves and the Chao1 estimator for species richness indicated the diversity in any substrate was not fully sampled, but for soil it came close. Amajority of the D. discoideum-associated bacteria were edible by D. discoideum and supported its growth (75.2% for feces and 81.8% for soil habitats). However, we found several bacteria genera were able to evade phagocytosis and persist in D. discoideum cells through one or more social cycles. This study focuses not on the entire D. discoideum microbiome, but on the culturable subset of bacteria that have important eukaryote interactions as prey, symbionts, or pathogens. These eukaryote and bacteria interactions may provide fertile ground for investigations of bacteria using amoebas to gain an initial foothold in eukaryotes and of the origins of symbiosis and simple microbiomes.