Oishi Wakana, Sato Mikiko, Kubota Kengo, Ishiyama Ryoka, Takai-Todaka Reiko, Haga Kei, Katayama Kazuhiko, Sano Daisuke
Department of Civil and Environmental Engineering, Graduate School of Engineering, Tohoku University, Sendai, Japan.
Department of Frontier Sciences for Advanced Environment, Graduate School of Environmental Studies, Tohoku University, Sendai, Japan.
Front Microbiol. 2022 Mar 31;13:848439. doi: 10.3389/fmicb.2022.848439. eCollection 2022.
Slaked lime (calcium hydroxide) is a commonly used disinfectant for fecal sludge. Although viruses are inactivated by lime treatment, whether RNA viruses adapt to lime treatment has not yet been determined. Here, we show that murine norovirus developed higher tolerance during serial passages with lime treatment. We compared synonymous and non-synonymous nucleotide diversities of the three open reading frames of viral genome and revealed that virus populations were subjected to enhanced purifying selection over the course of serial passages with lime treatment. Virus adaptation to lime treatment was coincident with amino acid substitution of lysine to arginine at position 345 (K345R) on the major capsid protein VP1, which accounted for more than 90% of the population. The infectious clones with the K345R produced using a plasmid-based reverse genetics system exhibited greater tolerance in a lime solution, which indicated that the specific amino acid substitution was solely involved in the viral tolerance in lime treatment.
熟石灰（氢氧化钙）是一种常用于粪便污泥的消毒剂。虽然病毒可通过石灰处理而失活，但RNA病毒是否会适应石灰处理尚未确定。在此，我们表明，鼠诺如病毒在经石灰处理的连续传代过程中产生了更高的耐受性。我们比较了病毒基因组三个开放阅读框的同义核苷酸多样性和非同义核苷酸多样性，发现病毒群体在经石灰处理的连续传代过程中受到了更强的纯化选择。病毒对石灰处理的适应性与主要衣壳蛋白VP1上第345位赖氨酸到精氨酸的氨基酸替换（K345R）一致，该替换在群体中占比超过90%。使用基于质粒的反向遗传学系统产生的具有K345R的感染性克隆在石灰溶液中表现出更高的耐受性，这表明特定的氨基酸替换单独参与了病毒在石灰处理中的耐受性。
