Abstract Background: UVB irradiation can cause acute damage such as sunburn, or photoaging and melanoma, all of which are major health threats. Objective: This study was designed to investigate the mechanism of skin photoaging induced by UVB radiation in mice through the analysis of the differential expression of miRNAs. Methods: A UVB irradiation photoaging model was constructed. HE and Masson special stains were used to examine the modifications in the epidermis and dermis of mice. The miRNA expression profiles of the mouse skin model exposed to UVB radiation and the normal skin of mice were analyzed using miRNA-sequence analysis. GO and Pathway analysis were employed for the prediction of miRNA targets. Results: A total of 23 miRNAs were evaluated for significantly different expressions in comparison to normal skin. Among them, 7 miRNAs were up-regulated and 16 were down-regulated in the skin with photoaging of mice exposed to UVB irradiation. The differential expression of miRNA is related to a variety of signal transduction pathways, among which mmu-miR-195a-5p and mitogen-activated protein kinase (MAPK) signal pathways are crucial. There was a significant differential expression of miRNA in the skin of normal mice in comparison with the skin with photoaging induced by UVB irradiation. Study limitations: Due to time and energy constraints, the specific protein level verification, MAPK pathway exploration, and miR-195a-5p downstream molecular mechanism need to be further studied in the future. Conclusions: UVB-induced skin photoaging can be diagnosed and treated using miRNA.

A series of novel 2-(thiophen-2-yl)-4H-chromen-3-yl-sulfonate derivatives (4a-4n) were synthesized and investigated for their in vitro free radical scavenging potential as well as cytotoxic efficacies against selected cancer cell lines. The cytotoxicity of the 4H-chromene derivatives (4a-4n) was evaluated according to three human cancer cell lines (HepG2, A549, HeLa) by utilizing a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Accordingly, part of the results exhibited better cytotoxic activities than that of the positive controls (4H-chromen-4-one and apigenin). Among them, compounds 4c-4g exhibited better training to the positive control against the three human cancer cell lines (half maximal inhibitory concentration (IC50) = 3.87 ± 0.12 to 21.38 ± 0.52 μM). Moreover, the extract of the 4H-chromene derivatives (4a-4n) showed better activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) in antioxidant assays compared to that of the positive control ascorbic acid (IC50 = 12.72 ± 0.27, 5.09 ± 0.21 μg mL−1). Thus, it can be confirmed from the bioassay results that the overall structural design, as well as proper substitution, is crucial in delivering anticipated biological effects. In this regard, spectroscopic techniques such as 1H nuclear magnetic resonance (NMR), 13C NMR, and high-resolution mass spectrometry (HRMS) were also carried out to confirm the final structures.

ABSTRACT Film mulching is an effective water-saving and yield-increasing measure for potato production in Northwest China. However, the response mechanism of microbial communities to mulching films in the soil is still unclear. In this study, polyethylene film mulching (PM), biodegradable film mulching (BM), liquid film mulching (LM), and non-mulching (NM) were applied on the drip-irrigated soil to investigate the effects of mulching films on soil bacterial and fungal communities through DNA sequencing, Pearson correlation analysis, and redundancy analysis. The results showed that LM treatment significantly increased the contents of soil mineral N (SMN), dissolved organic carbon (DOC), and dissolved organic nitrogen (DON) (p<0.05) in comparison with NM. The soil treated with LM presented high bacterial OTUs (operational taxonomic units), Chao1, ACE, and Shannon indices; however, the same indexes of fungi were low in LM and BM treatments. At the phylum level, Proteobacteria, Actinobacteria, and Chloroflexi were dominant bacterial communities. The LM treatment increased the OTUs of Proteobacteria ; PM treatment increased the OTUs of Actinobacteria and Chloroflexi. Ascomycota was the dominant fungal community, which were decreased in soil under mulching films. In terms of soil properties, DON was closely correlated (p<0.05) with the microbial OTUs, Chao1, and ACE indices. The DOC and SWC (soil water content) contributed 51.2 % to the change of bacterial structure; however, the fungal structure was less sensitive to the variation of soil properties. Our results indicate that liquid film mulching favors increasing the diversity and abundance of dominant bacterial species, which were associated with the variation of soil properties.

ABSTRACT In sandy areas of Northern Shaanxi, after potato harvest, there are large areas of soil exposed to wind erosion from winter to spring, leading to degradation of soil quality. Planting cover crops in fallow fields is considered effective to improve soil biological properties; however, there is scarce study on the effect of winter cover crops on fallow soils in this region. In the study lasting from 2017 to 2019, four winter cover crops, i.e., alfalfa (AC), sweetclover (SC), winter wheat (WC), and ryegrass (RC), as well as bare land (CK), were used to study the effect of winter cover crops on soil microbial characteristics. The experiment showed that the soils in AC treatment had the highest values of microbial biomass N (MBN) content, dehydrogenase and urease activities, bacteria colonies, and Shannon and Richness indices. The soils in SC treatment had the maximum values of microbial biomass C (MBC) content, protease activity, fungi colonies, and Simpson index. Under AC and SC treatments, microbial communities in soil showed the highest percentage of carbon source utilization for amino acids, carbohydrates, and amines. Alfalfa and sweetclover as cover crops were helpful to improve the activity and diversity of soil microorganisms, exerting a positive effect on soil quality. This finding is of great significance for improving the methods of mitigating soil degradation in winter fallow fields of Northern Shaanxi, China.