Written by Charlotte Harrison, Science Writer.
A new paper in Nature Microbiology shows that people who live to be at least 100 have a diverse collection of viruses in their gut that might protect them from infections. The findings add to increasing evidence that the ecology of the gut microbiome helps prevent age-related disorders.
The study characterized the gut viral genome — or virome — using previously published metagenome datasets of 195 centenarians from Japan and Sardinia, two regions with a high proportion of centenarians. The virome data from these individuals were compared with data from young (>18 years) and old (>60 years) adults.
The researchers found that the virome of centenarians was more diverse than that of the other groups, and included previously undescribed viral genera, such as viruses associated with Clostridia bacteria. In addition, the virus population of centenarians had more viruses in the lytic state – the active stage of the virus life-cycle during which viruses kill the bacteria they infect.
The researchers also investigated the functions of the virome that might influence the physiology of gut bacteria. They found that around a quarter of the centenarian virome encoded genes involved in sulphate metabolism.
Moreover, the microbiome of centenarians had a greater potential for specific metabolic activity, namely converting methionine to homocysteine, sulphate to sulphide and taurine to sulphide. This finding indicates that centenarians likely have a greater metabolic output of microbial hydrogen sulphide.
The authors believe that the higher level of hydrogen sulphide supports mucosal integrity and resistance to pathogenic microbes, helping the centenarians to stay healthy.
“This snapshot of how the virome interacts with gut microbiomes could tell us about how microbial and viral ecology evolves over the lifetime of a person,” said study author Ramnik Xavier in a press release. the Broad. “This offers an important starting point for uncovering the mechanisms behind how the gut ecosystem maintains health.”