Amazing stuff! I am scratching my head and wonder why this was never before investigated or discovered! Lack of technology/methods?
"... These ... genetic pieces are known as extrachromosomal DNA (ecDNA) and, while they can play a role in the development and growth of cancerous tumors, they can also help maintain our telomeres, protective caps at the ends of our chromosomes involved in the aging process. ...
Seeking to explore the possibility of ecDNA existing in human saliva, researchers ... got a "big" surprise as they carried out a new study. Not only did they find ecDNA in the oral microbiome hidden inside bacteria known as Streptococcus salivarius, they found comparatively giant chunks of it. They named these chunks "Inocles." ..."
"Researchers ... have made a surprising discovery hiding in people’s mouths: Inocles, giant DNA elements that had previously escaped detection. These appear to play a central role in helping bacteria adapt to the constantly changing environment of the mouth. The findings provide fresh insight into how oral bacteria colonize and persist in humans, with potential implications for health, disease and microbiome research. ...
“We know there are a lot of different kinds of bacteria in the oral microbiome, but many of their functions and means of carrying out those functions are still unknown,” ... “By exploring this, we discovered Inocles, an example of extrachromosomal DNA — chunks of DNA that exist in cells, in this case bacteria, but outside their main DNA. ..."
From the abstract:
"Survival strategy of bacteria is expanded by extrachromosomal elements (ECEs). However, their genetic diversity and functional roles for adaptability are largely unknown.
Here, we discover a novel family of intracellular ECEs using 56 saliva samples by developing an efficient microbial DNA extraction method coupled with long-read metagenomics assembly.
Even though this ECE family was not hitherto identified, our global prevalence analysis using 476 salivary metagenomic datasets elucidates that these ECEs reside in 74% of the population.
These ECEs, which we named, “Inocles”, are giant plasmid-like circular genomic elements of 395 kb in length, including Streptococcus as a host bacterium.
Inocles encode a series of genes that contribute to intracellular stress tolerance, such as oxidative stress and DNA damage, and cell wall biosynthesis and modification involved in the interactions with oral epithelial cells.
Moreover, Inocles exhibit significant positive correlations with immune cells and proteins responding to microbial infection in peripheral blood. Intriguingly, we examine and find their marked reductions among 68 patients of head and neck cancers and colorectal cancers, suggesting its potential usage for a novel biomarker of gastrointestinal cancers. Our results suggest that Inocles potentially boost the adaptive capacity of host bacteria against various stressors in the oral environment."
Giant DNA discovered hiding in your mouth Three-quarters of all people may host newly identified genetic material called Inocles, which could impact research on oral health, immunity, and even cancer risk (original news release)
Giant extrachromosomal element “Inocle” potentially expands the adaptive capacity of the human oral microbiome (open access)
Functional characterization of Inocle. A schematic describing what Inocles do and where they’re found. It shows the kinds of roles its genes might have, and how those jobs could be connected to things happening in the human body.
Fig. 3: Identification and characterizations of the four Inocle taxa.
No comments:
Post a Comment