[Effects of simvastatin on pulmonary fibrosis and endothelial - mesenchymal transition in the pulmonary fibrosis tissue of rats].

Objective: To investigate the effects of simvastatin (SIM) on pulmonary fibrosis and the expression of VE-cadherin(VE-cad),vimentin(VIM) and alpha-smooth muscle actin(α-SMA)in the pulmonary fibrosis tissue of rats. Methods: Sixty healthy male SD rats were randomly divided into control group(group A), bleomycin group(group B), 5 mg SIM group (group C) and 10 mg SIM group (group D),15 rats in each group. The model of rat pulmonary fibrosis was established by itraperitoneal injection of bleomycin(5 mg/kg). Since the first day of modeling, the rats of group C and D were treated with simvastatin suspension 5 mg/(kg·d) and 10 mg/(kg·d) by intragastric administration everyday, and the rats of group A and B were treated with equal volume of saline 10 ml/(kg·d) everyday. Five rats of each group were sacrificed randomly at the 7th, 14th and 28th day. Masson staining was used to observe the morphological changes of lung tissue in rats. The degree of fibrosis in lung tissues of each group was evaluated by the content of hydroxyproline (HYP) . The microvessel density (MVD) was analyzed by immunohistochemistry,The expressions of protein and mRNA of VE-cad, VIM and α-SMA were determined by immunohistochemistry and RT-PCR. Results: ①Compared with group A, the levels of HYP and MVD, the mRNA and protein expression levels of VIM and α-SMA in lung tissues of groups B, C and D were increased significantly at the 7th, 14th and 28th day(all P＜0.05), which reached highest level at the 28th day. However, the mRNA and protein expression levels of VE-CAD were decreased significantly at the corresponding time (P＜0.05), which reached lowest level at 28th day. ②Compared with group B, the levels of HYP and MVD, the mRNA and protein expression levels of VIM and α-SMA in groups C and D were decreased at the 7th, 14th and 28th day (all P＜0.05), which were decreased more obviously in group D at the 28th day. However, the mRNA and protein expression levels of VE-CAD were increased at the corresponding time (all P＜0.05), which were increased more obviously in group D at the 28th day. Conclusion: Simvastatin can reduce the degree of pulmonary fibrosis in rats through inhibiting the process of EnMT, which can enhance the expression of VE-cad and reduce the expression of VIM and α-SMA.

[Effect of Land-use on Soil Fungal Community Structure and Associated Functional Group in Huixian Karst Wetland].

Studying the impact of land-use on fungal communities and their functional groups in wetland soil can provide a theoretical basis for the protection of wetlands. The top soil (0-20 cm) samples were collected from the wetlands with Phragmites communis (PCW), wetlands with Cladium chinense (CCW), abandoned paddy fields (APF), paddy fields (PF), and corn fields (CF) in the Huixian Karst Wetland. The fungal community structure and its functional groups were analyzed using high-throughput sequencing methods and the FUNGuild database, respectively. The results showed that the Simpson and Shannon index in PF and CF were significantly higher than those in PCW and CCW. Ascomyceta was the most dominant phylum in five land-use types with the abundance of 70.60%-87.02%, followed by Rozellomycota in PCW with the abundance of 7.14% and Basidiomycota in CCW, APF, PF, and CF with the abundance of 9.70%, 5.19%, 8.13%, and 7.50%, respectively. Pleosporales was the most dominant order in PCW with the abundance of 16.47%, while Hypocreales was the dominant one in CCW, APF, PF, and CF with the abundance of 22.52%, 23.50%, 17.60, and 23.80%, respectively. Ascobolus and Archaeorhizomyces were the most dominant genera in PCW and CCW with the abundance of 6.65% and 13.44%, respectively, and Fusarium was the most dominant genus in APF, PF, and CF with the abundance of 10.22%, 10.51%, and 11.12%, respectively. Saprotroph was the main trophic mode in the Huixian wetland with the abundance of 48.67%-80.13%. The abundance of pathotroph in CF (5.39%) was higher than that in PCW (2.34%) and CCW (1.53%). Dung saprotroph-wood saprotroph and soil saprotroph were the most dominant functional groups in PCW and CCW, respectively, while animal pathogen-endophyte-lichen parasite-plant pathogen-soil saprotroph-wood saprotroph was the most dominant functional group in APF, PF, and CF. Redundancy analysis showed that both soil water content and the ratio of carbon-to-nitrogen were the main factors affecting fungal communities, and available nitrogen was the main factor affecting the functional groups. Overall, the results indicated that land-use has changed the soil fungal diversity and community structure, complicated the functional groups, and increased the risk of corn disease in the Huixian Karst wetland.

[Community Structure of CO2-fixing Soil Bacteria from Different Land Use Types in Karst Areas].

Carbon dioxide (CO2)-fixing bacteria are important microbial communities of the soil carbon cycle. It is important to study their community structure characteristics in karst areas to understand the carbon-sequestration mechanism of the soil ecosystem. The top soil samples of paddy fields, maize fields, and citrus orchards were collected in a karst area, mixed zone, and non-karst area at the Maocun karst experimental site in Guilin.The community abundance, composition, and diversity of CO2-fixing bacteria were analyzed using high-throughput sequencing technology with cbbLR as indicating gene. The results show that most of the CO2-fixing bacteria can only be classified as the shallow taxonomic group including bacteria and actinomycetes. The α-Proteobacteria of Proteobacteria was the dominant class in the three areas. Facultative autotrophic bacteria dominated by rhizobia were the main CO2-fixing bacteria. The abundances of Burkholderiales, Rhodopseudomonas, Azospirillum, Sinorhizobium fredii HH103, Rhizobium leguminosarum bv. trifolii were higher in the karst area than in the other two areas. However, Bradyrhizobium is the dominant species in the mixing and non-karst areas. The redundancy analysis shows that the pH, soil organic carbon, soluble organic carbon, cation exchange capacity, and total nitrogen are the main ecological factors affecting the community structure of CO2-fixing bacteria. The above-mentioned results show that the soil properties in the karst area can significantly affect the community structure of CO2-fixing bacteria.

[Comparison of Soil Bacterial Community Structure Between Paddy Fields and Dry Land in the Huixian Karst Wetland, China].

In order to explore the effect of land-use change on soil bacteria in wetland systems, the topsoil (0-20 cm) of a natural wetland (NW), paddy field (PF), and dry land (DL) were collected in the Huixian karst wetland. The α-diversity, species composition, and abundance of soil bacterial communities were analyzed using high-throughput sequencing. The effect of environmental factors on bacterial community structure was also examined. The results showed that the soil bacteria in the Huixian karst wetland can be divided into 49 phyla and 145 classes. The Shannon index of bacteria in the PF was significantly higher, and the Simpson index of bacteria in the NW is significantly lower, than in the other two land-use types. The dominant phyla (operational taxonomic units, OTUs>1%) in the NW were Proteobacteria (52.15%), Actinobacteria (15.16%), and Acidobacteria (8.80%); the dominant phyla in the PF were Proteobacteria (45.79%), Acidobacteria (17.20%), and Chloroflexi (11.75%); the dominant phyla in the DL were Proteus (51.42%), Acidobacteria (15.51%), and Chloroflexi (7.43%). The dominant classes (OTUs>1%) in the NW were α-Proteobacteria (17.98%), ß-Proteobacteria (13.72%), and Actinobacteria (13.13%); the dominant classes in the PF were Acidobacteria (14.35%), ß-Proteobacteria (13.37%), and δ-Proteobacteria (12.02%); the dominant classes in the DL were α-Proteobacteria (19.44%), Formobacteria (13.30%), and Acidobacteria (13.03%). Among the dominant OTUs (>0.3%), the dominant genera of in the NW were Sphingomonas (OTU2, 59), Micromonospora (OTU5, 24 and 50487), Gemmatimonas (OTU1), and Tenotrophomonas (OTU8); the dominant genera in the PF were Lysobacter (OTU4 and 115) and Aquabacterium (OTU33); the dominant genera in the DL were Sphingomonas (OTU85, 157 and 2916), Rhodanobacter (OTU19 and 52), and Penlobacterium (OTU60). A heatmap showed that there were significant differences in soil bacterial community structure among the three land-use types. Redundancy analysis showed that pH, soil organic carbon (SOC), total nitrogen (TN), alkali-hydrolyzable nitrogen (AN), exchangeable Mg2+, exchangeable Ca2+, soluble organic carbon (DOC), and available phosphorus (AP) were the main factors that affected the bacterial community structure in the Huixian karst wetland. These results indicate that changes in land-use types have significantly shaped the structure of soil bacterial communities in this area.