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Ruminants are important for global food security but emit the greenhouse gas methane. Rumen microorganisms break down complex carbohydrates to produce volatile fatty acids and molecular hydrogen. This hydrogen is mainly converted into methane by archaea, but can also be used by hydrogenotrophic acetogenic and respiratory bacteria to produce useful metabolites. A better mechanistic understanding is needed on how dietary carbohydrates influence hydrogen metabolism and methanogenesis. We profiled the composition, metabolic pathways, and activities of rumen microbiota in 24 beef cattle adapted to either fiber-rich or starch-rich diets. The fiber-rich diet selected for fibrolytic bacteria and methanogens resulting in increased fiber utilization, while the starch-rich diet selected for amylolytic bacteria and lactate utilizers, allowing the maintenance of a healthy rumen and decreasing methane production (p p p

Background Cytomegalovirus (CMV) has been recognized as one of the frequently occurring opportunistic infections (OIs) reported in the patients having human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS). In addition, it has been identified as the factor leading to gastrointestinal (GI) tract disorder among HIV/AIDS population. CMV exhibits broad cell tropism in different organs. This study evaluated the CMV cell tropism and clinicopathological characteristics of CMV infection in the different GI regions in HIV/AIDS cases. Methods Using nucleic acid in situ hybridization (ISH), CMV was detected in the gastrointestinal mucosal biopsy samples. The paraffin-embedded samples were stained with hematoxylin and eosin (HE) and immunohistochemistry (IHC), respectively. Results A total of 32 HIV/AIDS patients were enrolled in this study. Fourteen of these patients underwent gastroscopy, while the remaining eighteen received colonoscopy. CMV-infected cells were observed at 46 GI sites. Among them, the colon was the region with the highest susceptibility to GI CMV infection (n = 12, 26.1%). The CMV giant cell inclusion bodies were detected in epithelial cells and mesenchymal cells, including histiocytes, smooth muscle cells, fibroblasts, and endothelial cells. In the duodenum, there were markedly more positive epithelial cells than mesenchymal cells (p = 0.033). In contrast, in the esophagus (p = 0.030), cardia (p = 0.003), rectum (p = 0.019), colon (p p p = 0.035 and 0.036, respectively). Conclusions The colon has been identified as the GI site with the highest susceptibility to CMV infection. There are different CMV-infected cells in the different sites of the GI that relate to the expression level of PDGFRα and Nrp2. CMV DNA positive in the blood is related to the positive CMV cell count, as well as ulceration in the GI tract.