![]() Perturbation of the intestinal microbiota, or dysbiosis, is associated with various diseases such as inflammatory bowel disease ( 6) and also affects the efficacy of various vaccines in children ( 7). The intestinal microbiota of children only becomes adult-like at 2–3 years of age ( 5). Colonization of the GI tract is a gradual process in which Escherichia coli and other enterobacteria colonize the intestinal tract early after birth, followed by the subsequent establishment of anaerobes ( 4). These commensals are involved in nutrient metabolism, development, and functioning of the gastrointestinal (GI) immune system and protection of the host from pathogens ( 1– 3). Intestinal commensals constitute more than 1,000 species of bacteria. Collectively, it appears that the selected G− probiotic is more effective than the various tested G+ probiotics in enhancing protective immunity against rotavirus in the gnotobiotic piglet model. These probiotics modulate the pathogenesis of infectious diseases and protective immunity against pathogens in a species- and strain-specific manner. In this review, we discuss the differences between G+ and G− probiotics/commensals in modulating the dynamics of selected infectious diseases and host immunity. Although the health benefits of probiotics have been confirmed, the specific effects of these established Gram-positive (G+) and Gram-negative (G−) probiotics in modulating immunity against pathogens and disease are largely undefined. and Escherichia coli Nissle 1917 are two probiotics that are commonly used in children to treat various medical conditions including human rotavirus diarrhea and inflammatory bowel disease. Intestinal commensals play a major role in development of the immune system in neonates and in shaping host immune responses to pathogens. The role of intestinal microbiota and probiotics in prevention and treatment of infectious diseases, including diarrheal diseases in children and animal models, is increasingly recognized. Food Animal Health Research Program (FAHRP), Veterinary Preventive Medicine Department, The Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH, USA.Huang-Chi Huang Gireesh Rajashekara Linda J. Chattha † Lulu Shao † Anand Kumar † Stephanie N. On the other hand, our study implies that living organisms could actively neutralize environmental oxidative stress.David D. Depending on their concentration levels, different reactive oxygen species (ROS) combat and survival mechanisms might be initiated by different bacterial types including production of metalloregulatory proteins and ROS scavengers. The results from this study implied that the microbial inactivation by nZVI primarily results from Fe 2+ and Fe 3+ on the particle surface. coli, and a more stable form of iron was produced for E. XPS data showed strikingly different surface chemistry for nZVI particles after reacting with B. High magnetic removal efficiencies were observed for bacteria under the conditions tested, except for Gram-positive ones mixed with nZVI particles followed by addition of Fe 3+. ROS data showed inactivations of bacterial cells could also have resulted from in vivo damage by increased intracellular ROS levels. However, the inactivation of the iron combinations was shown to vary greatly with bacterial types. In general, the culturing and viability tests showed that Fe 2+ had stronger inactivation effects on Gram-negative bacteria, while Fe 3+ inactivated more Gram-positive ones. For nZVI particles of 0.56 mg mL −1, the bacterial growth was promoted when increasing volume was added, more significantly for S. The experimental results revealed that Fe 2+ and Fe 3+ had stronger inactivation effects on all bacteria tested than nZVI under the experimental conditions this effect was especially pronounced for E. The inactivation was determined using an agar plate CFU counting method, and intracellular reactive oxygen species (ROS) was also measured. The iron and microbial mixtures were also subjected to magnetic separation, viability tests by BacLight kit and surface chemistry analysis by X-ray photoelectron microscopy ( XPS). ![]() niger and Staphylococcus aureus) and two Gram-negative bacteria ( Pseudomonas fluorescens and Escherichia coli) were subjected to treatment with nZVI particles (0.56 mg mL −1 = 0.01 mol Fe/L), Fe 2+ (0.01 mol L −1) and Fe 3+ (0.01 mol L −1) as well as their combinations with various volumes (10-1000 μL) under aerobic conditions. Two Gram-positive bacteria ( Bacillus subtilis var. This study investigated the biological responses of Gram-positive and Gram-negative bacteria to nZVI particles, Fe 2+ and Fe 3+ ions.
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