A specific class of infectious agents isolated from bovine serum and dairy products and peritumoral colon cancer tissue

The in silico analyses of 109 replication-competent genomic DNA sequences isolated from cow milk and its products (97 in the bovine meat and milk factors 2 group – BMMF2, and additional 4 in BMMF1) seems to place these in a specific class of infectious agents spanning between bacterial plasmid and circular ssDNA viruses. Satellite-type small plasmids with partial homology to larger genomes, were also isolated in both groups. A member of the BMMF1 group H1MBS.1 was recovered in a distinctly modified form from colon tissue by laser microdissection. Although the evolutionary origin is unknown, it draws the attention to the existence of a hitherto unrecognized, broad spectrum of potential pathogens. Indirect hints to the origin and structure of our isolates, as well as to their replicative behaviour, result from parallels drawn to the Hepatitis deltavirus genome structure and replication.

我们对从牛乳及其制品中分离得到的109条具有复制能力的基因组DNA序列开展了硅基分析（in silico analysis）：其中97条归属于牛肉与牛乳因子2组（bovine meat and milk factors 2 group, BMMF2），剩余4条属于BMMF1组。分析结果提示，此类序列隶属于一类介于细菌质粒与环状单链DNA病毒（circular ssDNA viruses）之间的特殊传染性病原体类群。两组样本中均分离得到与较大基因组存在部分同源性的卫星型小质粒。研究人员通过激光显微切割技术，从结肠组织中分离得到了经显著修饰的BMMF1组成员H1MBS.1。尽管其进化起源尚不明确，但该类群的发现引发了学界对一类此前未被认知的广谱潜在致病菌的关注。本研究分离株的起源、结构以及复制特性的间接线索，均来自于与丁型肝炎病毒（Hepatitis deltavirus）基因组结构与复制过程的类比推论。