Fecal microbiota transfer between young and aged mice reverses hallmarks of the aging gut, eye, and brain

Background: Altered intestinal microbiota composition in later life is associated with inflammaging, declining tissue function, and increased susceptibility to age-associated chronic diseases, including neurodegenerative dementias. Here, we tested the hypothesis that manipulating the intestinal microbiota influences the development of major comorbidities associated with aging and, in particular, inflammation affecting the brain and retina. Methods: Using fecal microbiota transplantation, we exchanged the intestinal microbiota of young (3 months), old (18 months), and aged (24 months) mice. Whole metagenomic shotgun sequencing and metabolomics were used to develop a custom analysis workflow, to analyze the changes in gut microbiota composition and metabolic potential. Effects of age and microbiota transfer on the gut barrier, retina, and brain were assessed using protein assays, immunohistology, and behavioral testing. Results: We show that microbiota composition profiles and key species enriched in young or aged mice are successfully transferred by FMT between young and aged mice and that FMT modulates resulting metabolic pathway profiles. The transfer of aged donor microbiota into young mice accelerates age-associated central nervous system (CNS) inflammation, retinal inflammation, and cytokine signaling and promotes loss of key functional protein in the eye, effects which are coincident with increased intestinal barrier permeability. Conversely, these detrimental effects can be reversed by the transfer of young donor microbiota. Conclusions: These findings demonstrate that the aging gut microbiota drives detrimental changes in the gut–brain and gut–retina axes suggesting that microbial modulation may be of therapeutic benefit in preventing inflammation-related tissue decline in later life. [MediaObject not available: see fulltext.] Graphical abstract: [Figure not available: see fulltext.

Bacteriophage PRD1 as a potential surrogate for adenovirus in drinking water disinfection with free chlorine, low pressure ultraviolet light, and sunlight

Waterborne pathogens are increasingly a worldwide concern in drinking water because of their ability to cause high levels of morbidity and mortality. Especially in developing regions, a lack of access to safe drinking water, adequate sanitation, and resources to implement water treatment processes contributes to the spread of pathogens. Emerging pathogens are also of concern in water treatment for communities in developed regions as they can be highly resistant to specific treatment technologies. Viruses are of particular concern in water treatment not only because of their virulence and ability to have high resistance to inactivation, but also because of the limited knowledge available. Human pathogenic viruses are not easy to study in the laboratory or in the field because of strict biosafety regulations and the use of expensive cell culture methods that are time consuming. Often it is not practical to perform testing with human pathogens, and therefore surrogates can be used. Currently, there is a need to develop proper surrogates especially for adenovirus, a human enteric pathogen found globally in drinking water sources. Adenovirus is known to be highly resistant to disinfection technologies such as ultraviolet (UV) light, combined chlorine, and solar disinfection. A potential surrogate for adenovirus is the bacteriophage PRD1 because of its similar size, morphology, and genome replication mechanism. The objective of this research was to compare the inactivation kinetics of PRD1 with that of adenovirus when exposed to free chlorine, low pressure ultraviolet light, and solar disinfection to determine if PRD1 is an appropriate surrogate. Using PRD1 as a surrogate would enable field testing to determine the efficacy of current and emerging water treatment technologies, more rapid and non virulent laboratory experiments, and the use of a surrogate for determining the mechanisms of inactivation of adenovirus

Characterizing Bacteriophage PR772 as a Potential Surrogate for Adenovirus in Water Disinfection: A Comparative Analysis of Inactivation Kinetics and Replication Cycle Inhibition by Free Chlorine

Elucidating mechanisms by which pathogenic waterborne viruses become inactivated by drinking water disinfectants would facilitate the development of sensors to detect infectious viruses and novel disinfection strategies to provide safe water. Using bacteriophages as surrogates for human pathogenic viruses could assist in elucidating these mechanisms; however, an appropriate viral surrogate for human adenovirus (HAdV), a medium-sized virus with a double-stranded DNA genome, needs to be identified. Here, we characterized the inactivation kinetics of bacteriophage PR772, a member of the <i>Tectiviridae</i> family with many similarities in structure and replication to HAdV. The inactivation of PR772 and HAdV by free chlorine had similar kinetics that could be represented with a model previously developed for HAdV type 2 (HAdV-2). We developed and tested a quantitative assay to analyze several steps in the PR772 replication cycle to determine if both viruses being inactivated at similar rates resulted from similar replication cycle events being inhibited. Like HAdV-2, we observed that PR772 inactivated by free chlorine still attached to host cells, and viral DNA synthesis and early and late gene transcription were inhibited. Consequently, free chlorine exposure inhibited a replication cycle event that was post-binding but took place prior to early gene synthesis for both PR772 and HAdV-2

Analysis of the Viral Replication Cycle of Adenovirus Serotype 2 after Inactivation by Free Chlorine

Free chlorine is effective at inactivating a wide range of waterborne viral pathogens including human adenovirus (HAdV), but the mechanisms by which free chlorine inactivates HAdV and other human viruses remain to be elucidated. Such advances in fundamental knowledge are key for development of new disinfection technologies and novel sensors to detect infectious viruses in drinking water. We developed and tested a quantitative assay to analyze several steps in the HAdV replication cycle upon increasing free chlorine exposure. We used quantitative polymerase chain reaction (qPCR) to detect HAdV genomic DNA as a means to quantify attachment and genome replication of untreated and treated virions. Also, we used quantitative reverse-transcription PCR (RT-qPCR) to quantify the transcription of E1A (first early protein) and hexon mRNA. We compared these replication cycle events to virus inactivation kinetics to determine what stage of the virus replication cycle was inhibited as a function of free chlorine exposure. We observed that adenovirus inactivated at levels up to 99.99% by free chlorine still attached to host cells; however, viral DNA synthesis and early E1A and late hexon gene transcription were inhibited. We conclude that free chlorine exposure interferes with a replication cycle event occurring postbinding but prior to early viral protein synthesis

Future of waterborne virus research to provide safe drinking water globally.

<p>Gaining a better understanding of how viruses become inactivated by disinfectants requires detailed studies of many virus types and disinfectants to determine what stage of the virus replication cycle becomes blocked, and what modifications to the viral protein and/or genome lead to inactivation. The development of sensors to detect infectious viruses in drinking water will benefit from these studies and is also necessary to ensure safe drinking water.</p