Studies on virus-host relationships and genome organisation of viruses infecting hyperthermophilic acidophilic archaea of the genus Acidianus

对地球上病毒多样性的程度和分布的研究应有助于了解病毒在微生物生态学和整个生态系统中的作用。对病毒多样性的全面了解也有助于了解病毒的起源和进化，可能还有助于了解细胞进化的早期阶段。由于形态的显著多样性表明其具有广泛的系统发育跨度，古细菌的病毒，主要是那些在炎热生境中茁壮成长的病毒，特别有希望成为进化研究的对象。这些病毒也为理解高温下生命的生物化学提供了可理解的模型系统，也为建立嗜热古菌的转化和表达系统提供了可能性。该项目的目的是研究9种新型病毒和病毒样颗粒，这些病毒和病毒样颗粒是由嗜热古菌属酸化菌菌株产生的，我们在美国怀俄明州黄石国家公园酸性温泉（pH值2.85°C）的富集培养中发现的。四种类型的颗粒在形态上类似于已知的嗜热古细菌Sulfolobus和Thermoproteus的病毒。其他粒子的形态是独特的，以前在自然界中没有观察到。我们计划为每个病毒和病毒样颗粒分离一个天然宿主，研究颗粒结构和与宿主的关系，并确定和分析基因组的核苷酸序列。

Studies of the extent and distribution of viral diversity on the planet should help to understand the role of viruses in microbial ecology and the entire ecosystem. A comprehensive picture of viral diversity could also contribute to understanding the orgin and evolution of viruses, and probably very early stages of cellular evolution. Because of the remarkable diversity of their morphologies suggesting a broad phylogenetic span, viruses of the archaea, mainly of those thriving in hot habitats, are especially promising objects of evolutionary studies. Such viruses also offer comprehensible model systems for understanding the biochemistry of life at high temperatures, as well as possibilities to establish transformation and expression systems for hyperthermophilic archaea. The aim of the project is to study 9 novel viruses and virus-like particles produced by strains of the hyperthermophilic archaeal genus Acidianus, which we have discovered in enrichment cultures from a sample from an acidic hot spring (pH 2, 85°C) in Yellowstone National Park, Wyoming, USA. Four types of particles morphologically resemble known viruses of the hyperthermophilic archaea Sulfolobus and Thermoproteus. Morphologies of other particles are unique, not observed previously in nature. We plan to isolate a natural host for each of the viruses and virus-like particles, study particle structures and relationships with hosts, and determine and analyse nucleotide sequences of the genomes.