Livestock grazing modifies soil nematode body size structure in mosaic grassland habitats.

Body size is closely related to the trophic level and abundance of soil fauna, particularly nematodes. Therefore, size-based analyses are increasingly prominent in unveiling soil food web structure and its responses to anthropogenic disturbances, such as livestock grazing. Yet, little is known about the effects of different livestock on the body size structure of soil nematodes, especially in grasslands characterized by local habitat heterogeneity. A four-year field grazing experiment from 2017 to 2020 was conducted in a meadow steppe characterized by typical mosaics of degraded hypersaline patches and undegraded hyposaline patches to assess the impacts of cattle and sheep grazing on the body size structure of soil nematodes within and across trophic groups. Without grazing, the hypersaline patches harbored higher abundance of large-bodied nematodes in the community compared to the hyposaline patches. Livestock grazing decreased large-bodied nematodes within and across trophic groups mainly by reducing soil microbial biomass in the hypersaline patches, with sheep grazing resulting in more substantial reductions compared to cattle grazing. The reduction in large-bodied nematode individuals correspondingly resulted in decreases in nematode community-weighted mean (CWM) body size, nematode biomass, and size spectra slopes. However, both cattle and sheep grazing had minimal impacts on the CWM body size and size spectra of total nematodes in the hyposaline patches. Our findings suggest that livestock grazing, especially sheep grazing, has the potential to simplify soil food webs by reducing large-bodied nematodes in degraded habitats, which may aggravate soil degradation by weakening the bioturbation activities of soil fauna. In light of the widespread land use of grasslands by herbivores of various species and the ongoing global grassland degradation of mosaic patches, the recognition of the trends revealed by our findings is critical for developing appropriate strategies for grassland grazing management.

Changes in plant community assembly from patchy degradation of grasslands and grazing by different-sized herbivores.

Grassland degradation caused by increases in livestock grazing threatens a variety of ecosystem services. Understanding changes in plant community assembly during the process of grassland degradation in the presence of grazing is important to help restore degraded grasslands worldwide but has received little attention thus far. The grassland degradation process is typified by heterogeneous degradation, that is, gradual formation of degraded patches (hereafter "patchy degradation"). Here, we experimentally examined the effects of herbivore grazing and patchy degradation on plant community assembly using nine pairs of non-degraded (intact) and patch-degraded (fragmented) grasslands subject to grazing by different-sized herbivores (i.e., NG, no grazing; SG, sheep grazing; CG, cattle grazing) over 4 years. Using a null-model approach, we estimated the relative magnitude of deterministic processes of community assembly by comparing the observed and expected ß-diversity. We found that in the absence of herbivore grazing, deterministic processes played a greater role in community assembly, regardless of whether patchy degradation had occurred. However, the deterministic processes resulted in plant communities being more spatially similar in non-degraded grasslands while being more dissimilar in patchy degraded grasslands. Compared with non-degraded grasslands, species with strong competitive abilities (i.e., Leymus chinensis) were less dominant in patchy degraded grasslands, indicating relaxed competition and a reduced role of species interactions over plant communities. Instead, patchy degradation added the role of environmental variables over plant communities. SG consistently promoted more stochastic plant community assembly in both non-degraded and patch-degraded grasslands, while CG promoted more stochastic plant community assembly only in the non-degraded state, having no effect in the patch-degraded state. Our study offers important insights into changes in plant community assembly during ongoing patch-degradation of grasslands, indicating the role of increased environmental filtering of soil and reduced species interactions in driving plant community dynamics with increasing grassland patchy degradation. We also uncovered an herbivore species-specific effect on plant community assembly during the process of grassland degradation, which will better inform and improve future grassland restoration planning efforts.

Regulation of NEAT1/miR-214-3p on the growth, migration and invasion of endometrial carcinoma cells.

OBJECTIVE: To investigate the function and mechanism of lnc NEAT1 in regulating the growth, migration and invasion of endometrial carcinoma (EC) cells. MATERIALS AND METHODS: NEAT1 and miR-214-3p levels were measured by qRT-PCR. The protein levels of HMGA1, ß-catenin, c-myc and MMP9 were evaluated by Western blot. The effects of NEAT1, HMGA1, miR-214-3p on the viability, migration and invasion of HEC-1A cells were accessed by WST-1 assay and transwell migration/invasion assay. The effect of miR-214-3p on Wnt signaling activity was tested by luciferase reporter assay. RESULTS: NEAT1, HMGA1 and ß-catenin were significantly upregulated in EC tissues, and miR-214-3p was significantly downregulated. NEAT1 promoted the growth, migration and invasion of HEC-1A cells, and mRNA level of Wnt/ß-catenin downstream genes c-myc and MMP9. In addition, HMGA1 upregualted the protein and mRNA levels of Wnt/ß-catenin downstream genes c-myc and MMP9, and could improve cell viability, and increase numbers of migration and invasion of HEC-1A cells. miR-214-3p overexpression inhibited the proliferation, migration and invasion of HEC-1A cells, while NEAT1 overexpression reversed these effects. miR-214-3p overexpression inhibited the activity of Wnt/ß-catenin pathway, while NEAT1 overexpression reversed this effect. Then, si-HMGA1 reduced the activity of Wnt/ß-catenin pathway. Moreover, we found NEAT1 and HMGA1 bound to miR-214-3p by luciferase reporter assay, and NEAT1 and HMGA1 expression were negatively correlated with miR-214-3p. CONCLUSION: NEAT1 regulates HMGA1 via miR-214-3p to regulate Wnt/ß-catenin pathway, thus promotes the growth, migration and invasion of HEC-1A cells.