Browsing by Author "Knights, Dan"
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Item Data from "Diverse Bacterial Communities Exist on Canine Skin and are Impacted by Cohabitation and Time"(2016-11-17) Johnson, Timothy; Torres, Sheila; Danzeisen, Jessica; Clayton, Jonathan; Ward, Tonya; Knights, Dan; Huang, Hu; joh04207@umn.edu; Johnson, TimothyThis related study sampled 40 dogs from 20 households over the course of three seasons. Three skin sites were examined. The goal of the study was to determine if a core skin microbiome exists in dogs across time and body site, and if cohabitation impacts sharing of the skin microbiome. This dataset is a part of the Torres_Johnson Canine Microbiome Study.Item The relationship of gut microbiota in standard and overweight children, before and after probiotic administration(2019) Linhardt, Carter A; Clayton, Jonathan B; Hoops, Suzie; Amin-Nordin, Syafinaz; Knights, DanThe usage of probiotic foods and supplements has been widely considered part of a healthy diet by supplementing the gut microbiome with beneficial bacteria. Although the usage of probiotics is a common dietary accessory, there is limited reproducible evidence showing bacterial colonization, thus limiting long term effectiveness. We administered Yakult, a commercial probiotic composed of Lactobacillus paracasei strain Shirota, to overweight and standard weight school children in Malaysia. Using a crossover intervention study design, two groups of school children were administered the probiotic supplement or continued their typical diet in sequential 5-week intervention periods, separated by a 5-week washout period. Fecal samples were collected every five weeks over the course of the 15-week study period. The gut microbiome of each subject was analyzed using 16S rRNA gene sequencing. We observed significant differences in Lachnospiraceae, Coproccus, Roseburia, Pyramidobacter, and Bacteroides ovatus between weight classes. However, differences in overall microbiome diversity between weight classes were not found to be significant. Subjects clustered according to their relative abundance of well-known genera Bacteroides and Prevotella, regardless of age, gender, or weight class. Overall, individual-to-individual variation overshadowed trends in gut microbiome composition associated with probiotic administration.Item Relationships between cecum, ileum and litter bacterial microbiomes in a commercial turkey flock, and the impact of penicillin treatment on early bacterial community establishment(2015-10-19) Danzeisen, Jessica; Clayton, Jonathan; Huang, Hu; Knights, Dan; McComb, Brian; Hayer, Shivdeep; Johnson, Timothy; joh04207@umn.edu; Johnson, TimothyGut health is paramount for commercial poultry production, and methods to assess gut health are critically needed to better understand how the avian gastrointestinal tract matures over time. One important aspect of gut health is the totality of bacterial populations inhabiting different sites of the avian gastrointestinal tract, and associations of these populations with the poultry farm environment, since these bacteria are thought to drive metabolism and prime the host immune system. In this study, a single flock of commercial turkeys was followed over the course of twelve weeks to examine bacterial microbiome inhabiting the ceca, ileum, and corresponding poultry litter. Furthermore, the effects of low-dose, growth-promoting penicillin treatment (50 g/ton) in feed on the ileum bacterial microbiome were also examined during the early brood period. The cecum and ileum bacterial communities of birds shifted independently but in parallel to one another over time, with distinct bacterial populations harboring each site. Corresponding poultry litter more closely represented the ileal bacterial populations than cecal bacterial populations, and also changed parallel to ileum bacterial populations over time. Penicillin applied at low doses in feed significantly enhanced early weight gain in commercial poults, and this correlated with predictable shifts in the ileum bacterial populations in control versus treatment groups. Overall, this study demonstrates the dynamic shifts in the turkey gastrointestinal microbiome during development, the correlations between bacterial populations in the gastrointestinal tract and the litter environment, and the impact of low-dose penicillin on the modulation of bacterial communities in the ileum. Alternatives to low-dose antibiotics would benefit by mimicking these effects in the gut, among others.Item Wild Primate Gut Microbiota Protect Against Obesity(2017-04) Sidiropoulos, Dimitrios, N; Clayton, Jonathan; Al-Ghalith, Gabe; Shields-Cutler, Robin; Ward, Tonya; Blekhman, Ran; Kashyap, Purna; Knights, DanThe gastrointestinal tract hosts trillions of bacteria that play major roles in metabolism, immune system development, and pathogen resistance. Although there is increasing evidence that low dietary fiber in Westernized societies is associated with dramatic loss of natural human gut microbiome diversity, the role of this loss in obesity and inflammation is not well understood. Non-human primates (NHPs) can be used as model systems for studying the effects of diet and lifestyle disruption on the human gut microbiome. Captive primates are typically exposed to low-fiber diets and tend to have human-associated microbiota in place of their native microbiota. In order to explore interactions between the gut microbiota and dietary fiber, we transplanted captive and wild primate gut microbiota into germ-free mice and then exposed them to either a high- or low-fiber diet. We found that the group receiving low-fiber diet and captive primate microbiota became obese and had high levels of circulating inflammatory cytokines, while mice receiving high-fiber diet and wild primate microbiota remained healthy. Mice with the wild primate microbiota and low-fiber diet acquired intermediate levels of obesity, demonstrating an interaction between dietary fiber and the microbiota. These results show that the modern human gut microbiome interacts with low-fiber diets to cause inflammation and obesity, and suggest a possible clinical role for manipulation of the microbiota in the treatment of obesity.