Abstract:[Background] The imbalance of human energy homeostasis is characterized by underweight, overweight and obesity. Gut microbiota is related to the maintenance of human energy homeostasis, but the feature of gut microbiota in different body mass index (BMI) populations need to be further explored. [Objective] To explore the feature and the co-occurrence network of gut microbiota of four BMI groups based on the American gut project (AGP), and to provide new theoretical basis for intervention of obesity and underweight based on gut microbiota. [Methods] Screen the gut microbiota samples with BMI information from AGP dataset, and divide the screened samples into four categories according to the BMI classification standards set by the World Health Organization:underweight (BMI<18.5 kg/m2), normal weight (18.52), overweight (252), obesity (BMI>30 kg/m2). By calculating and comparing the alpha diversity and beta diversity of gut microbiota, the overall feature and differences of gut microbiota in four BMI groups were explored. Use Microbiome Multivariable Association with Linear Models (MaAsLin) to analyze the correlation between different BMI groups and gut microbiota, and add geographical, age, and gender factors as confounding factors to the model for correction. SparCC was used to calculate the correlation of gut microbiota among the four BMI groups, and the gut microbiota co-occurrence network of four groups was constructed. [Results] The decreasing trend of alpha diversity in the underweight, overweight and obese population compared to the normal weight population was observed after the Wilcoxon-rank-sum analysis. As for the beta diversity, the significant difference of the structure of gut microbiota between the four BMI groups was found. There was no significant difference in the relative contents of Firmicutes and Bacteroidetes. Through MaAsLin analysis, and adding geographical, age, and gender factors as confounding factors to the model for correction, a total of 49 bacteria that were significantly related to BMI types were obtained. The topological structure of the co-occurrence network of the four groups of BMI populations were different. The networks of underweight and normal-weight population were more complex, while the networks of overweight and obese populations were less complex. [Conclusion] There were differences in the diversity, overall feature and co-occurrence network of the gut microbiota among the four BMI groups.

Abstract:[Background] As the largest inland basin in China, the Tarim Basin is a natural laboratory for studying the responses of bacterial communities to the environment on a local scale. Although researchers have studied the bacterial diversity in the Tarim Basin, few of them have studied the diversity and distribution pattern of bacterial communities in plant habitats of the Tarim Basin. [Objective] This study investigated and analyzed the diversity and distribution pattern of bacterial communities in plant habitats in the Tarim Basin, laying the foundation for subsequent research on bacterial ecology in the region. [Methods] We conducted a large-scale and systematic field survey and sampling of the soil in a plant habitat of the Tarim Basin to analyze the bacterial community structure and diversity. Furthermore, we explored the changes of soil bacterial diversity and community spatial pattern along geographic and climatic gradients on a large scale and the assembly process of phylogenetic groups at the continental level. [Results] The species composition, network structures, and assembly processes of bacterial communities showed significant differences between the plant habitat and the desert habitat. Notably, the soil bacterial communities in the plant habitat showed greater stability and complexity than those in the desert habitat. The null model analysis showed that heterogeneous selection and diffusion limitation were the key ecological processes in the bacterial community assembly. [Conclusion] This study reveals the diversity and driving factors of soil bacterial communities in three habitats of the Tarim Basin. The findings provide data and research basis for understanding the safety and stability of ecosystems in the arid zone in the context of global change and give insights into the fragility and assembly processes of plant habitat ecosystems in arid zones.

Abstract:[Background] Traditional Shanxi mature vinegar is produced by solid-state fermentation with multiple strains in an open environment. Revealing the composition, interaction network, and source of microbial community facilitates the understanding and regulation of the vinegar fermentation process. [Objective] To reveal the composition, succession, interaction network, and source of microbial community in Shanxi mature vinegar during the fermentation process. [Methods] High-throughput DNA sequencing was performed to reveal the composition, succession, and diversity of the microbial community. SPSS was employed to calculate the Spearman correlation coefficient between species and Gephi was used for the visual analysis of the microbial interaction network. Fast expectation-maximization microbial source tracking (FEAST) was employed to analyze the origin of the microorganisms. [Results] Six bacterial genera and five fungal genera (average relative abundance greater than 1%) were dominant in the fermentation process of Shanxi mature vinegar. The average relative abundance of Acetobacter, Lactobacillus, and Saccharomycopsis were 20.76%, 30.38%, and 46.24%, respectively. The relative abundance of Acetobacter increased gradually during acetic acid fermentation, while the opposite trend was observed for Lactobacillus. The microbial community interaction network showed that Weissella, Lactococcus, Meyerozyma, Loigolactobacillus, Schleiferilactobacillus, and Geobacter had high connectivity (≥7). In addition, Acetobacter demonstrated significant antagonism with Weissella, Schleiferilactobacillus, Loigolactobacillus, Lactococcus, and Meyerozyma. The results of source tracking showed that 1.02% of bacteria and 77.04% of fungi were derived from Daqu on the second day of saccharification. On the first day of acetic acid fermentation, 0.93% of bacteria and 52.82% of fungi were derived from fermented grains. [Conclusion] This study provided important theoretical data for understanding the composition, succession, and interaction network of microbial community and tracking the source of microorganisms during the fermentation process of Shanxi mature vinegar.

Abstract:[Background] Bacteria of hypolithic biological soil crusts (BSCs) in Gobi play an important role in the biogenic elements circling in arid and semi-arid regions. The bacterial community structure and diversity vary greatly due to different climatic and geographical environments. The area of Zhongyang Gobi is large, but little is known so far about the structure and diversity of the hypolithic bacteria community. [Objective] To compared and analyzed the similarities and differences of bacterial community structure and diversity in hypolithic BSCs and bare soil around in the Zhongyang Gobi, and discover the effect of environmental factors on bacterial community and the interaction relationships among the bacteria. [Methods] Illumina MiSeq was applied to sequence 16S rRNA gene, bioinformatics approach was used to reveal the diversity and structure of the bacteria community, the co-occurrence network was constructed based on CoNet software and Cytoscape 3.5.1 to visualize the network. [Results] The contents of available phosphorus (AP), available nitrogen (AN) and chlorophyll a (Chl a) of the soil were significantly higher (the most of 471% higher), while pH were slightly lower in the BSCs than that in the bare soil. The bacteria was mostly dominated by the phylum of Cyanobacteria (45.85%?53.77%) and by the genera Trichocoleus, Chroococcidiopsis and unknown one belonged to Class Cyanobacteria (9.25%?18.42%) in the hypolithic BSCs, and did by the phylum of Actinobacteria (38.82%?44.69%) and by the genera Arthobacter, Rubrobacter and three unknown genera belonged to the phylum of Actinobacteria or Acidobacteria (>5%) in the adjacent bare soil. Among all the soil physicochemical factors, AP had the most significantey influence on the composition of hypolithic bacterial communities. Except the genera of Actognophytocola and one unclassified of Class Cyanobacteria, there were strong interaction existed among other phylotypes, in which the co-occurrence relationship was dominant (about 60%) and the nodes were all belonged to Phylum Cyanobacteria and Class α-Proteobacteria with higher degree, closeness and betweenness centralities. [Conclusion] Bacterial diversity and community structure of hypolithic BSCs is remarkably distinguished from that of bare soil in the Zhongyang Gobi. Members of Phylum Cyanobacteria and Class α-Proteobacteria are the primary and most important driver in the early development of hypolithic BSCs in the Zhongyang Gobi.