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Plateau pikas (Ochotona curzoniae) play a keystone role in the alpine meadow ecosystem on the Qinghai–Tibetan Plateau (QTP). For decades, QTP grasslands have become degraded to some degree, largely as a result of heavy livestock grazing. Concomitantly, the abundance of plateau pikas has increased dramatically as grassland degradation has altered the vegetation community structure and dominant species, shifting the plant nutrient contents toward higher protein conditions that favor them. Considerable research supports the hypothesis that the quantity and quality of food limit herbivore populations. Here, we examined the relationship between the availability of essential amino acids in the diets of plateau pikas and the degree of meadow degradation associated with livestock grazing intensity through a field survey, as well as the fitness of individuals by laboratory feeding experiments with 2 pelleted chows containing 0.26% and 0.45% methionine. Sulfur-containing methionine and cystine were the most limiting amino acids in the diets of pikas. During the pika breeding season, the concentrations of most essential acids, particularly methionine and cystine, were higher in heavily degraded meadows than in lightly and moderately degraded meadows. Individuals fed 0.45% methionine exhibited enhanced cell-mediated immunity, reduced intensity of coccidian infection, and increased concentrations of gonadotropin-releasing hormone, luteinizing hormone, estradiol, progesterone, and testosterone compared to those fed 0.26% methionine. These results showed that heavily degraded meadows provided relatively high-quality food that improved individual fitness, suggesting that the high-methionine food in the heavily degraded meadows may be a key factor in the generation and maintenance of high-density populations of plateau pikas. [ABSTRACT FROM AUTHOR]

Ribosomal protein L13 (RPL13) is highly conserved in evolution. At present, the properties and functions of RPL13 have not been characterised in insects. In this study, Bombyx mori RPL13 (BmRPL13) was first found to be specifically recruited to the sites of ultraviolet (UV)‐induced DNA damage and contributed to UV damage repair. Escherichia coli expressing BmRPL13 showed better resistance to UV radiation. After knocking down the expression of BmRPL13 in BmN cells, the repair speed of UV‐damaged DNA slowed down. The further results showed that BmRPL13 interacted with B. mori nucleopolyhedrovirus (BmNPV) ORF65 (Bm65) protein to locate at the UV‐induced DNA damage sites of BmNPV and helped repair UV‐damaged viral DNA. [ABSTRACT FROM AUTHOR]

Lymphadenectomy is critical in the clinical prognosis of ovarian cancer patients. Therefore, we assessed whether lymph node ratio (LNR) has predictive value on overall survival (OS) of patients with serous epithelial ovarian cancer (SEOC). A total of 7,815 eligible SEOC patients were identified from the Surveillance, Epidemiology, and End Results (SEER) database, who underwent surgical resection between 1973 and 2013. We used the time-dependent receiver operating characteristic (ROC) curve and the area under curve to determine the optimal cut-off value of LNR. The predictive role of LNR was analyzed by Cox proportional hazards regression model. The effects of LNR and positive lymph nodes (PLN) on OS were evaluated by comparing the time-dependent ROC curves. The time-dependent ROC curves showed that the optimal LNR cut-off value was 42.0% for nodal-positive SEOC. As shown in Kaplan-Meier survival curves, survival was significantly poorer for all patients with LNR≥42.0% (log-rank test: P

Plateau pikas (Ochotona curzoniae) play a keystone role in the alpine meadow ecosystem on the Qinghai–Tibetan Plateau (QTP). For decades, alpine meadows on the QTP have suffered from severe degradation, predominantly due to livestock grazing and frequent dramatic increases in plateau pikas. The cause has long been thought to be that livestock grazing provides open habitats for pikas. However, open habitats with low food nutrient quality are insufficient to maintain high-density populations. Feeding facilitation is a process or action undertaken by one species whose activity benefits another species. However, the facilitative effects on population consequences remain unclear. Here, we examined the impact of feeding facilitation on the population dynamics of plateau pikas. We hypothesize that the high protein amount provided by meadows that have been overgrazed would be an important factor leading to dramatic increases in plateau pikas. We found that plateau pikas preferred high-protein foods, and relatively abundant high-protein food resources were found in meadows following high levels of livestock grazing. Body mass and amount of protein in stomach digesta of pikas were higher in moderately and heavily grazed meadows than in lightly grazed meadow. Thus, pika population density was associated with high-protein food resources. A supplemental protein experiment confirmed that high-protein foods led to higher pika population density by increasing reproductive performance. Livestock grazing increased the abundance of plateau pikas by shifting plant nutrient contents toward higher protein conditions favorable to them. Feeding facilitation is an important factor that causes a dramatic increase in plateau pikas. [ABSTRACT FROM AUTHOR]