Identification and Characterization of Circular Single-Stranded DNA Genomes in Sheep and Goat Milk

Abstract

In recent years, a variety of circular replicase-encoding single-stranded (CRESS) DNA viruses and unclassified virus-like DNA elements have been discovered in a broad range of animal species and environmental samples. Key questions to be answered concern their presence in the human diet and their potential impact on disease emergence. Especially DNA elements termed bovine meat and milk factors (BMMF) are suspected to act as co-factors in the development of colon and breast cancer. To expand our knowledge on the occurrence of these potential pathogens in human nutrition, a total of 73 sheep and 40 goat milk samples were assayed by combining rolling circle amplification (RCA), PCR and Sanger sequencing. The present study further includes retail milk from the aforementioned species. We recovered 15 single stranded (ss) circular genomes. Of those, nine belong to the family Genomoviridae and six are members of the unclassified group of BMMF. Thus, dairy sheep and goats add to dispersal of CRESS viruses and circular ssDNA elements, which enter the food chain via milk. The presence of these entities is therefore more widespread in Bovidae than initially assumed and seems to be part of the common human nutrition.

Structural expression of bovine milk and meat factors in tissues of colorectal, lung and pancreatic cancer patients

“…BMMFs pose a novel class of infectious agents based on their similarities to both known viruses, as well as a cryptic bacterial plasmid 10 . Presently, more than 200 isolates have been described based on their DNA genome composition 6,7,9,10,21‐23 . BMMF infections have been described as responsible factors in indirect carcinogenesis in CRC and other cancers based on the induction of chronic inflammation.…”

“…10 Presently, more than 200 isolates have been described based on their DNA genome composition. 6,7,9,10,[21][22][23] BMMF infections have been described as responsible factors in indirect carcinogenesis in CRC and other cancers based on the induction of chronic inflammation. The latter is visualized by increased numbers of CD68 + macrophages.…”

Potential Pathogenic Impact of Cow’s Milk Consumption and Bovine Milk-Derived Exosomal MicroRNAs in Diffuse Large B-Cell Lymphoma

“…These infectious agents share characteristics of both bacterial plasmids and known viruses [ 253 ]. Recently, circular single-stranded DNA genomes have been identified in the milk of sheep and goats [ 254 ] as well as the milk of water buffaloes [ 255 ]. Thus, dairy cows, sheep, goats, and water buffaloes add to the dispersal of CRESS viruses and circular ssDNA elements, which enter the human food chain via milk consumption [ 248 , 249 , 254 , 255 ].…”

“…Recently, circular single-stranded DNA genomes have been identified in the milk of sheep and goats [ 254 ] as well as the milk of water buffaloes [ 255 ]. Thus, dairy cows, sheep, goats, and water buffaloes add to the dispersal of CRESS viruses and circular ssDNA elements, which enter the human food chain via milk consumption [ 248 , 249 , 254 , 255 ]. According to de Villiers and Zur Hausen, future transcription analyses of acute lymphatic leukemias searching for BMMF-like infections will be of substantial interest [ 256 ].…”

A New Circular Single-Stranded DNA Virus Related with Howler Monkey Associated Porprismacovirus 1 Detected in Children with Acute Gastroenteritis

“…The extensive use of next-generation sequencing on a variety of biological samples revealed an enormous variety of new viruses [ 1 , 2 , 3 ]. Particularly, viruses recently identified and coined as circular, Rep-encoding ssDNA (CRESS DNA) has a huge diversity and were detected in samples of eukaryotic hosts [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. Many of the species belong to the phylum Cressdnaviricota and were classified into two genera, eight orders, eleven families, and sixty-six genera; many of the species are uncultured and remain unclassified [ 15 ].…”