Exploring viral diversity in raw sewage. wastewater metagenome

Currently virology is focused on the study of a relatively small number of viral species. Specific viruses are studied either because they are easily propagated in the laboratory or because they are associated with disease. The lack of knowledge of the size and characteristics of the viral universe and the diversity of viral genomes is a roadblock to understanding important issues such as the origin of emerging pathogens and the extent of gene exchange among viruses. Untreated wastewater is an ideal system for assessing viral diversity because virion populations from large numbers of individuals are deposited and because raw sewage itself provides a rich environment for the growth of diverse host species, and thus their viruses. These studies suggest that the viral universe is far more vast and diverse than previously suspected. Raw sewage was collected and virus particles were purified by milk flocculation.

当前病毒学研究主要聚焦于数量相对有限的病毒物种。学界针对特定病毒开展研究，主要出于两类动因：一是该病毒可在实验室中便捷增殖传代，二是其与疾病存在关联。我们对全球病毒圈（viral universe）的规模、特征以及病毒基因组多样性的认知不足，这成为理解诸多关键科学问题的阻碍——例如新发病原体的起源，以及病毒间基因交换的范围。未处理污水是评估病毒多样性的理想体系：一方面，来自大量宿主个体的病毒粒子（virion）种群会在此富集；另一方面，原生污水本身可为多样的宿主物种提供充足的生长环境，进而为其携带的病毒提供繁衍条件。此类研究表明，全球病毒圈的规模与多样性远超此前的预判。研究人员收集了原生污水，并通过牛奶絮凝法纯化了其中的病毒粒子。