A primary component of exercise, mechanical signals, when applied in the form of low intensity vibration (LIV), increases mesenchymal stem cell (MSC) osteogenesis and proliferation. While it is generally accepted that exercise effectively combats the deleterious effects of aging in the musculoskeletal system, how long-term exercise affects stem cell aging, which is typified by reduced proliferative and differentiative capacity, is not well explored. As a first step in understanding the effect of long-term application of mechanical signals on stem cell function, we investigated the effect of LIV during in vitro expansion of MSCs. Primary MSCs were subjected to either a control or to a twice-daily LIV regimen for up to sixty cell passages (P60) under in vitro cell expansion conditions. LIV effects were assessed at both early passage (EP) and late passage (LP). At the end of the experiment, P60 cultures exposed to LIV maintained a 28% increase of cell doubling and a 39% reduction in senescence-associated β-galactosidase activity (p < 0.01) but no changes in telomere lengths and p16^INK4a levels were observed. Prolonged culture-associated decreases in osteogenic and adipogenic capacity were partially protected by LIV in both EP and LP groups (p < 0.05). Mass spectroscopy of late passage MSC indicated a synergistic decrease of actin and microtubule cytoskeleton-associated proteins in both control and LIV groups while LIV induced a recovery of proteins associated with oxidative reductase activity. In summary, our findings show that the application of long-term mechanical challenge (+LIV) during in vitro expansion of MSCs for sixty passages significantly alters MSC proliferation, differentiation and structure. This suggests LIV as a potential tool to investigate the role of physical activity during aging.

Telomere length dynamics are an established biomarker of health and aging in animals. The study of telomeres in numerous species has been facilitated by methods to measure telomere length by real-time quantitative PCR (qPCR). In this method, telomere length is determined by quantifying the amount of telomeric DNA repeats in a sample and normalizing this to the total amount of genomic DNA. This normalization requires the development of genomic reference primers suitable for qPCR, which remains challenging in non-model organism with genomes that have not been sequenced. Here we report reference primers that can be used in qPCR to measure telomere lengths in any vertebrate species. We designed primer pairs to amplify genetic elements that are highly conserved between evolutionarily distant taxa and tested them in species that span the vertebrate tree of life. We report five primer pairs that meet the specificity and reproducibility standards of qPCR. In addition, we demonstrate how to choose the best primers for a given species by testing the primers on multiple individuals within a species and applying an established computational tool. These reference primers can facilitate the application of qPCR-based telomere length measurements in any vertebrate species of ecological or economic interest.

Vertebrate herbivores require symbiotic gastrointestinal (GI) microbes to extract energy and nutrients from fibrous and sometimes toxic plant diets. Because GI microbes vary in their relative abundance, function, and degree of specialization, the microbial community depends on both the characteristics of plants consumed and the anatomical, physiological, and behavioral characteristics of the herbivore host. To tease apart the relative contribution of diet and herbivore phylogeny to the microbiome, we leveraged a unique study system in which mule deer ( Odocoileus hemionus ) and white‐tailed deer ( O. virginianus ) had been hand‐raised from neonates to adulthood in identical conditions on a pelleted ration, then transitioned over 2 weeks in the spring onto natural plant diets as they foraged together in the same habitats across summer, then transitioned back onto the pelleted ration in late summer. We determined the plant composition and nutritional quality of the deers' diets using bite count techniques and analyzed 16S rRNA genes of their feces to determine microbial diversity and composition. Our experiments demonstrated that the GI microbial community of congeneric deer responded to characteristics of both diet and deer species. Alpha and beta microbial diversity and microbial composition differed when deer consumed the pelleted ration versus natural browse and varied with other dietary characteristics including plant diversity, composition of plant functional groups, and nutritional constituents. Microbial communities of the two deer species responded differently to dietary changes, but most strongly when deer selected different natural plant diets. Despite controlling early experience, innate behavior and physiological differences between species likely influenced the GI microbiome. Our findings underscore the potential disruption in GI microbial communities with rapid diet changes and the importance of diverse, high‐quality forages for wild ruminants. A better understanding of how sympatric herbivores use the same available resources is crucial for predicting the consequences of increasing overlap in wildlife distributions with climate change and human disturbances.

Although the impact of the SARS-CoV-2 pandemic on major metropolitan areas is broadly reported and readily available, regions with lower populations and more remote areas in the United States are understudied. The objective of this study is to determine the progression of SARS-CoV-2 sequence variants in a frontier and remote intermountain west state among university-associated communities. This study was conducted at two intermountain west universities from 2020 to 2022. Positive SARS-CoV-2 samples were confirmed by quantitative real-time reverse transcription-polymerase chain reaction and variants were identified by the next-generation sequencing of viral genomes. Positive results were obtained for 5355 samples, representing a positivity rate of 3.5% overall. The median age was 22 years. Viral genomic sequence data were analyzed for 1717 samples and phylogeny was presented. Associations between viral variants, age, sex, and reported symptoms among 1522 samples indicated a significant association between age and the Delta variant (B 1.167.2), consistent with the findings for other regions. An outbreak event of AY122 was detected August–October 2021. A 2-month delay was observed with respect to the timing of the first documented viral infection within this region compared to major metropolitan regions of the US.