Many studies have shown roles for endoplasmic reticulum stress (ERS)/unfolded protein response (UPR) signaling cascades with ovarian folliculogenesis, and oocyte maturation. In this study, we investigated seasonal changes in ERS and ovarian steroidogenesis in the muskrats (Ondatra zibethicus) during the breeding season (BS) and non-breeding season (NBS). There were noticeable seasonal variations in the weight and size of muskrat ovaries with values higher in the BS than that in NBS. The circulating luteinizing hormone (LH), follicle-stimulating hormone (FSH), 17β-estradiol, and progesterone of the female muskrats were higher during the BS. The RNA-seq data of ovaries during different seasons revealed 2580 differentially expressed genes, further analysis showed a prominent enrichment of ERS-related pathways and ovarian steroidogenesis pathway. Immunohistochemical results showed that GRP78 and steroidogenic enzymes (P450scc, 3β-HSD, P450c17, and P450arom) existed in the various kinds of cells in muskrat ovaries during the BS and NBS. In ovaries from the BS, the mRNA levels of P450scc, P450arom, P450c17, and 3β-HSD were considerably higher. Furthermore, the expression levels of oxidative stress-related genes (SOD2, CAT, and GPX1) and UPR signal genes (Bip/GRP78, ATF4, ATF6, and XBP1s) were increased strikingly higher during the BS in comparison with the NBS. However, the mRNA levels of CCAAT-enhancer-binding protein homologous protein (CHOP) and caspase-3 had no considerable difference between the BS and NBS. Taken together, these results suggested that UPR signaling associated with the seasonal changes in ovarian steroidogenesis is activated in the BS and the delicate balance in redox regulation is important for seasonal reproduction in the muskrats.

Aiming at two pivotal difficulties involved by similarity data mining in time series, namely effective mining of time series data with arbitrary length and that have biggish stochastic volatility, an algorithm of similarity mining in time series data on the basis of grey Markov SCGM(1, 1) model is proposed in this paper. Grey SCGM(1, 1) model is applied to seek for available information from time series data themselves, and then general change trend has been researched. Markov chain is applied to reveal stochastic volatility regularity and entropy is applied to measure similarity degree of time series. So applicable data scope of similarity mining in time series data is extended and efficiency of data mining is improved.

Prostaglandins (PGs) serve as signaling molecules that regulate various physiological processes, including inflammation, immune response, blood clotting and reproduction. The aim of this study was to investigate the immunolocalizations and expression patterns of prostaglandin-E2 (PGE2), cyclooxygenase (COX)-1 and COX-2, as well as its receptor subtypes 4 (EP4) in the scent glands of muskrats (Ondatra zibethicus) during the breeding and non-breeding periods. There were significant seasonal differences in the scent glandular mass, with higher values in the breeding season and relatively low in the non-breeding season. PGE2, EP4, COX-1 and COX-2 have been immunolocalized in the scent glandular and epithelial cells in both breeding and non-breeding seasons, whereas no immunostaining was observed in the interstitial cells. The protein and mRNA expression levels of EP4, COX-1 and COX-2 were higher in the scent glands of the breeding season than those of the non-breeding season. The mean mRNA levels of EP4, COX-1 and COX-2 were positively correlated with the scent glandular weights. The circulating follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (T) and PGE2, as well as scent glandular PGE2 and dihydrotestosterone (DHT) concentrations were also significantly higher in the breeding season. Additionally, the transcriptomic study in the scent glands identified that differentially expressed genes might be related to fatty carboxylic monocarboxylic acid, steroidogenic-related pathway and prostanoid metabolic process. These findings suggested that prostaglandin-E2 might play an essential autocrine or paracrine role in regulating seasonal changes in the scent glandular functions of the muskrats.

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