Institute of Microbiology, University Hospital Center and University of Lausanne, 1011 Lausanne, Switzerland.
Environ Microbiol. 2011 Jun;13(6):1454-66. doi: 10.1111/j.1462-2920.2011.02446.x. Epub 2011 Mar 9.
Large viruses infecting algae or amoebae belong to the NucleoCytoplasmic Large DNA Viruses (NCLDV) and present genotypic and phenotypic characteristics that have raised major interest among microbiologists. Here, we describe a new large virus discovered in Acanthamoeba castellanii co-culture of an environmental sample. The virus, referred to as Lausannevirus, has a very limited host range, infecting Acanthamoeba spp. but being unable to infect other amoebae and mammalian cell lines tested. Within A. castellanii, this icosahedral virus of about 200 nm exhibits a development cycle similar to Mimivirus, with an eclipse phase 2 h post infection and a logarithmic growth leading to amoebal lysis in less than 24 h. The 346 kb Lausannevirus genome presents similarities with the recently described Marseillevirus, sharing 89% of genes, and thus belongs to the same family as confirmed by core gene phylogeny. Interestingly, Lausannevirus and Marseillevirus genomes both encode three proteins with predicted histone folds, including two histone doublets, that present similarities to eukaryotic and archaeal histones. The discovery of Lausannevirus and the analysis of its genome provide some insight in the evolution of these large amoebae-infecting viruses.
感染藻类或变形虫的大型病毒属于核质大型 DNA 病毒（NCLDV），具有基因型和表型特征，引起了微生物学家的极大兴趣。在这里，我们描述了从环境样本的共生培养的粘菌变形虫中发现的一种新型大型病毒。该病毒被称为洛桑病毒，宿主范围非常有限，仅能感染粘菌变形虫属，但不能感染其他变形虫和测试的哺乳动物细胞系。在粘菌变形虫属中，这种约 200nm 的二十面体病毒表现出与 mimivirus 相似的发育周期，在感染后 2 小时进入潜伏期，对数生长期导致变形虫在不到 24 小时内裂解。346kb 的洛桑病毒基因组与最近描述的马赛病毒有相似之处，共享 89%的基因，因此通过核心基因系统发育树可知其属于同一科。有趣的是，洛桑病毒和马赛病毒基因组都编码了三个具有预测组蛋白折叠的蛋白，包括两个组蛋白二聚体，与真核生物和古菌的组蛋白具有相似性。洛桑病毒的发现及其基因组的分析为这些感染变形虫的大型病毒的进化提供了一些见解。
