BackgroundUrbanization is associated with an increased risk for a number of diseases, including obesity, diabetes, and cancer, which all also show associations with the microbiome. While microbial community composition has been shown to vary across continents and in traditional versus Westernized societies, few studies have examined urban-rural differences in neighboring communities within a single country undergoing rapid urbanization. In this study, we compared the gut microbiome, plasma metabolome, dietary habits, and health biomarkers of rural and urban people from a single Chinese province.ResultsWe identified significant differences in the microbiota and microbiota-related plasma metabolites in rural versus recently urban subjects from the Hunan province of China. Microbes with higher relative abundance in Chinese urban samples have been associated with disease in other studies and were substantially more prevalent in the Human Microbiome Project cohort of American subjects. Furthermore, using whole metagenome sequencing, we found that urbanization was associated with a loss of microbial diversity and changes in the relative abundances of Viruses, Archaea, and Bacteria. Gene diversity, however, increased with urbanization, along with the proportion of reads associated with antibiotic resistance and virulence, which were strongly correlated with the presence of Escherichia and Shigella. ConclusionsOur data suggest that urbanization has produced convergent evolution of the gut microbial composition in American and urban Chinese populations, resulting in similar compositional patterns of abundant microbes through similar lifestyles on different continents, including a loss of potentially beneficial bacteria and an increase in potentially harmful genes via increased relative abundance of Escherichia and Shigella.Electronic supplementary materialThe online version of this article (10.1186/s40168-017-0338-7) contains supplementary material, which is available to authorized users.

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Objective Eating away from home is associated with poor diet quality, in part due to less healthy food choices and larger portions. However, few studies take into account the potential additional contribution of differences in food composition between restaurant- and home-prepared dishes. This study aimed to investigate differences in nutrients of dishes prepared in restaurants vs. at home. Design Eight commonly consumed dishes were collected in 20 of each of the following types of locations: small and large restaurants, and urban and rural households. In addition, two fast-food items were collected from 10 KFC’s, McDonald’s, and food stalls. Five samples per dish were randomly pooled from every location. Nutrients were analyzed and energy was calculated in composite samples. Differences in nutrients of dishes by preparation location were determined. Setting Urban and rural. Subjects Sodium, potassium, protein, total fat, fatty acids, carbohydrate, and energy in dishes. Results On average, both the absolute and relative fat content, saturated fatty acid (SFA) and sodium/potassium ratio were higher in dishes prepared in restaurants than households (P<0.05). Protein was 15% higher in animal food-based dishes prepared in households than restaurants (P <0.05). Quantile regression models found that, at the 90th quantile, restaurant preparation was consistently negatively associated with protein and positively associated with the percentage energy from fat in all dishes. Moreover, restaurant preparation also positively influenced the SFA content in dishes, except at the highest quantiles. Conclusions These findings suggest that compared to home preparation, dishes prepared in restaurants in China may differ in concentrations of total fat, SFA, protein, and sodium/potassium ratio, which may further contribute, beyond food choices, to less healthy nutrient intake linked to eating away from home.

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Under the action of water, weak rock slopes easily expand and the strength and stiffness decrease, which results in slope instability. The styrene–acrylic emulsion cement-matrix composite, a new type of polymer curing agent, was developed for the curing and treatment of weak rock slopes. The strength-reduction factor method and ANSYS finite element software were used to calculate and analyze the stability of slopes before and after protection. The stability safety factor of weak rock after protection increased by 30% from 2.0 to 2.6. In order to evaluate the performance of the polymer curing agent, the mixture test was carried out in the laboratory. It was found that the waterproofness, hydrophobicity, and microstructure of weak rock slopes with the polymer curing agent can be significantly improved. Finally, the polymer curing agent was adopted and the external-soil spray-seeding technique was used in physical engineering. From test results, it was indicated that the polymer curing agent for weak slopes is beneficial in improving the water-damage resistance of a slope surface and prevent or reduce the softening of weak rock so that plants can grow for a long time. The treatment for weak rock slopes was successfully combined with plant protection, achieving the dual effect of weak rock slope protection and ecological protection.