Abstract Soil is the greatest reservoir of microorganisms, which are the main agents responsible for biogeochemical cycles, as well as for the decomposition of organic compounds and the supply of plant nutrients. Among all the microorganisms present in soil are the viruses, which influence the activity and ecology of other populations in the environment. As bacteria are the most common host of viruses in soil, most virus-like particles (VLPs) are considered to be bacteriophages. Since they can have an effect on the activity and ecology of bacteria, they can influence bacterial evolution by transduction, a mechanism of horizontal gene transfer in which the bacteriophage transfers DNA from one bacteria to another. Although viruses are the most abundant among all microorganisms and have great importance in the environment, viral diversity has not been well explored in soil. Because of this fact, the aim of the present study was to determine the best concentration method for the study of viral diversity. For that purpose, three concentration methods commonly used for viral study were selected and adapted to viral concentrations in soil samples: negatively charged HA membranes, polyethylene glycol (PEG) and ultracentrifugation (UF) were used, and viral diversity was evaluated by the random amplified polymorphic DNA (RAPD), transmission electron microscopy (TEM) and metagenomic approaches. Of the three concentration methods, the HA membrane showed the best results, more diverse in metagenomic analysis and with more VLP morphotypes, followed by ultracentrifugation. These techniques recovered viral particles of over 100 nm in size, while PEG recovered smaller particles. RAPD and TEM analyses were shown to be effective methods for the study of viral diversity, corroborating the data obtained by sequencing.

中文翻译：

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用于土壤样品多样性研究的病毒浓缩方法

摘要 土壤是微生物的最大库，微生物是生物地球化学循环、有机化合物分解和植物养分供应的主要媒介。在土壤中存在的所有微生物中，病毒是影响环境中其他种群活动和生态的病毒。由于细菌是土壤中最常见的病毒宿主，因此大多数病毒样颗粒 (VLP) 被认为是噬菌体。由于它们可以对细菌的活性和生态产生影响，它们可以通过转导影响细菌进化，这是一种水平基因转移机制，其中噬菌体将 DNA 从一种细菌转移到另一种细菌。尽管病毒是所有微生物中数量最多的，并且在环境中具有重要意义，土壤中的病毒多样性尚未得到很好的探索。由于这一事实，本研究的目的是确定用于研究病毒多样性的最佳浓缩方法。为此，选择了三种常用于病毒研究的浓缩方法并适应土壤样品中的病毒浓度：使用带负电荷的 HA 膜、聚乙二醇 (PEG) 和超速离心 (UF)，并通过随机扩增的方法评估病毒多样性。多态性 DNA (RAPD)、透射电子显微镜 (TEM) 和宏基因组学方法。在三种浓缩方法中，HA 膜显示出最好的结果，在宏基因组分析中更加多样化并且具有更多的 VLP 形态类型，其次是超速离心。这些技术回收了超过 100 nm 的病毒颗粒，而 PEG 回收了更小的颗粒。