The effects of low ambient temperature on steroidogenesis and mitochondrial functions in the testes of wild ground squirrels (Spermophilus dauricus).

Seasonal reproduction is a widely used breeding strategy in wildlife, especially vertebrates inhabiting temperate regions. Generally, ambient temperature is considered a significant factor influencing the reproductive status of animals. In the present study, wild ground squirrels (Spermophilus dauricus), typical seasonal breeders, were used as an animal model to investigate the mechanism behind the impact of low ambient temperature on testicular function. To simulate the winter environment of wild ground squirrels, we lowered the temperature gradient in the rearing environment to 4 °C. At sampling, the body surface temperature of the squirrels reared under normal ambient temperature (22 °C, NAT group) and the low ambient temperature (4 °C, LAT group) were 31.5 °C and 22.8 °C, respectively. Subsequently, we conducted immunohistochemical assays, qPCR, and enzyme-linked immunosorbent assays (ELISA) to examine the variations in testicular functions, as well as the dynamics and functions of mitochondria, in the squirrels of NAT and LAT groups. As a result, the levels of positive immunostaining for PCNA, P21, and P27 were significantly lower in the testes of LAT group, while the levels of immunostaining for Cleaved Caspase-3 and TUNEL were significantly higher. In addition, the low-temperature treatment reduced the expression level of steroidogenesis-related genes, including LHR, FSHR, GATA-4, P450scc, and P450arom, and decreased the testosterone concentration. Moreover, markers of mitochondrial fission and fusion, DRP1 and MFN2, respectively, were increased in the testes of LAT group. Additionally, the mRNA level of SOD1 was notably higher in the testes of LAT group. In conclusion, the low ambient temperature inhibited spermatogenesis, steroidogenesis, as well as mitochondrial dynamics and functions in the testes of wild ground squirrels.

The prognostic value of lymphatic metastatic size in head and neck squamous cell carcinoma.

BACKGROUND: Lymphatic metastatic size was proved to predict prognosis in different types of carcinomas, except in head and neck squamous cell carcinoma (HNSCC) located in hypopharynx, oropharynx and supraglottic region et al. The aim of this study is to evaluate the prognostic value of lymphatic metastatic size in HNSCC, which may guide clinical decision-making in practice. METHODS: From 2008 to 2022, 171 patients, who were diagnosed as HNSCC in our center, were included. The demographic data, clinicopathological characteristics and lymphatic metastatic size were recorded and analyzed using the Kaplan-Meier method and Cox regression analysis. RESULTS: Among 171 patients, 107 cases were hypopharyngeal cancer, 38 cases supraglottic cancer and 26 cases oropharyngeal cancer. The median of lymphatic metastatic size was 8 mm (range 0-46). According to lymphatic metastatic size, the patients were assigned to three subgroups: Group I (0 mm), Group II ( ≤ 10 mm) and Group III (> 10 mm). Kaplan-Meier analysis with log rank test revealed that Group I and Group II had similar locoregional control rate, distant metastasis free probability, disease-free survival and overall survival (all p > 0.05), whereas Group III had significant worse prognosis. Adjusted for demographic and other clinicopathological characteristics, lymphatic metastatic size was an independent predictor of disease-free survival and overall survival in HNSCC. CONCLUSIONS: Lymphatic metastatic size was an independently prognostic factor in HNSCC, which may assist in postoperative adjuvant treatment decisions.

Investigation of seasonal changes in lipid synthesis and metabolism-related genes in the oviduct of Chinese brown frog (Rana dybowskii).

A peculiar physiological characteristic of the Chinese brown frog (Rana dybowskii) is that its oviduct dilates during pre-brumation rather than during the breeding season. This research aimed to examine the expression of genes connected with lipid synthesis and metabolism in the oviduct of R. dybowskii during both the breeding season and pre-brumation. We observed significant changes in the weight and size of the oviduct between the breeding season and pre-brumation. Furthermore, compared to the breeding season, pre-brumation exhibited significantly lower triglyceride content and a marked increase in free fatty acid content. Immunohistochemical results revealed the spatial distribution of triglyceride synthase (Dgat1), triglyceride hydrolase (Lpl and Hsl), fatty acid synthase (Fasn), and fatty acid oxidases (Cpt1a, Acadl, and Hadh) in oviductal glandular cells and epithelial cells during both the breeding season and pre-brumation. While the mRNA levels of triglycerides and free fatty acid synthesis genes (dgat1 and fasn) did not show a significant difference between the breeding season and pre-brumation, the mRNA levels of genes involved in triglycerides and free fatty acid metabolism (lpl, cpt1a, acadl, acox and hadh) were considerably higher during pre-brumation. Furthermore, the R. dybowskii oviduct's transcriptomic and metabolomic data confirmed differential expression of genes and metabolites enriched in lipid metabolism signaling pathways during both the breeding season and pre-brumation. Overall, these results suggest that alterations in lipid synthesis and metabolism during pre-brumation may potentially influence the expanding size of the oviduct, contributing to the successful overwintering of R. dybowskii.

Expression of cholesterol synthesis and steroidogenic markers in females of the Chinese brown frog (Rana dybowskii) during prespawning and prehibernation.

The oviduct of the Chinese brown frog (Rana dybowskii) expands in prehibernation rather than in prespawning, which is one of the physiological phenomena that occur in the preparation for hibernation. Steroid hormones are known to regulate oviductal development. Cholesterol synthesis and steroidogenesis may play an important role in the expansion of the oviduct before hibernation. In this study, we investigated the expression patterns of the markers that are involved in the de novo steroid synthesis pathway in the oviduct of R. dybowskii during prespawning and prehibernation. According to histological analysis, the oviduct of R. dybowskii contains epithelial cells, glandular cells, and tubule lumens. During prehibernation, oviductal pipe diameter and weight were significantly larger than during prespawning. 3-Hydroxy-3-methylglutaryl CoA reductase (HMGCR), low-density lipoprotein receptor (LDLR), steroidogenic acute regulatory protein (StAR), cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc), and steroidogenic factor 1 (SF-1) were detected in epithelial cells in prehibernation and glandular cells during prespawning. HMGCR, LDLR, StAR, and P450scc protein expression levels were higher in prehibernation than during prespawning, but the SF-1 protein expression level did not significantly differ. HMGCR, LDLR, StAR, P450scc (CYP11A1), and SF-1 (NR5A1) mRNA expression levels were significantly higher in prehibernation compared with prespawning. The transcriptome results showed that the steroid synthesis pathway was highly expressed during prehibernation. Existing results indicate that the oviduct is able to synthesize steroid hormones using cholesterol, and that steroid hormones may affect the oviductal functions of R. dybowskii.

Seasonal patterns of prolactin, prolactin receptor, and STAT5 expression in the ovaries of wild ground squirrels (Citellus dauricus Brandt).

Prolactin (PRL) is a hormone crucial for normal reproduction, functioning as an autocrine, paracrine, and endocrine factor. This study aimed to examine the immunolocalization and expression patterns of PRL, prolactin receptor (PRLR), and signal transducer and activator of transcription 5 (STAT5) in the ovaries of wild ground squirrels during both breeding and non-breeding periods. Significant seasonal variations were observed in ovarian weights, with higher values during the breeding season and relatively lower values during the nonbreeding season. PRL, PRLR, STAT5, and p-STAT5 were immunolocalized in granulosa cells and luteal cells during the breeding season, whereas they were exclusively found in granulosa cells during the non-breeding season. The mRNA expression levels of Prl, Prlr, and Stat5 were increased in ovarian tissues during the breeding season compared to the non-breeding season. Moreover, the mean mRNA levels of Prl, Prlr, and Stat5 exhibited a positive correlation with ovarian weights. Both circulating PRL and ovarian PRL concentrations were significantly elevated during the breeding season. Additionally, transcriptomic analysis of ovarian tissues revealed differentially expressed genes possibly associated with ovarian function and mammary gland development, including ovarian follicle development, steroid synthesis, and regulation of reproductive process. These findings suggest that PRL might play an essential endocrine, autocrine, or paracrine role in the regulation of seasonal changes in the ovarian functions in wild ground squirrels.

Seasonal expressions of the translocator protein (18 kDa), voltage-dependent anion channel, and steroidogenic acute regulatory protein in the scent glands of muskrats (Ondatra zibethicus).

Steroidogenesis machinery involves the steroidogenic acute regulatory protein (StAR), which regulates cholesterol transfer within the mitochondria, and the transport of cholesterol via a channel composed of 18-kDa translocator protein (TSPO), the voltage-dependent anion channel (VDAC) plus some accessory proteins. In this study, we investigated the immunolocalizations and expressions of StAR, TSPO, VDAC and cytochrome P450 side chain cleavage enzyme (P450scc, CYP11A1) in the scent glands of muskrats (Ondatra zibethicus) during the breeding and non-breeding periods. StAR, TSPO, VDAC and CYP11A1 were immunolocalized in the scent glandular, interstitial and epithelial cells in both breeding and non-breeding seasons with stronger immunostaining in the breeding season. The mRNA expression levels of StAR, TSPO, VDAC and CYP11A1 were higher in the scent glands of the breeding season than those of the non-breeding season. The circulating follicle stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T) as well as scent glandular T 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 the lipid metabolic process, integral component of membrane, and steroid hormone receptor activity and hormone activity using GO analysis. Further in vitro study verified that StAR, TSPO, VDAC and CYP11A1 expression levels increased significantly after human chorionic gonadotropin, hCG/FSH treatment compared with the control group. The KEGG pathway enriched by differentially expressed genes detected to be involved in endocrine system or amino acid metabolism. These findings suggested that the scent glands of the muskrats have ability to synthesize steroids de novo, and that the steroid hormones may have an important regulatory role in the scent glandular function via an autocrine/paracrine pathway.

A hybrid event-triggered stabilization approach for switched systems under asynchronous switching and its application.

This paper investigates the stabilization problem of switched systems with mismatched modes by an event-triggered control approach. A hybrid event-triggered scheme (HETS) with a dynamically adjustable threshold is newly proposed, which combines periodic sampling, continuous event-trigger and slow switching. It is assumed that the modes and states of the controller are updated only at each triggering instant, so the situation of asynchronous switching could arise. Compared with the control strategy under static HETS, the proposed hybrid event-triggered control strategy has the advantage of potentially speeding up the stabilization while reducing the communication burden. To ease the analysis, the closed-loop system is accordingly represented as a combination of the switched system with a periodically sampled control input and the one with a continuously event-triggered control input. By considering input delay information in the construction of multiple Lyapunov-Krasovskii functional (LKF), a discontinuous and non-positive definite LKF is developed to establish sufficient conditions on the exponential stability for the closed-loop switched system. The design method of the desired controller and HETS is then provided. Finally, the result obtained in this paper is applied to a networked continuous stirred tank reactors system.

Vomeronasal Receptors Associated with Circulating Estrogen Processing Chemosensory Cues in Semi-Aquatic Mammals.

In numerous animals, one essential chemosensory organ that detects chemical signals is the vomeronasal organ (VNO), which is involved in species-specific behaviors, including social and sexual behaviors. The purpose of this study is to investigate the mechanism underlying the processing of chemosensory cues in semi-aquatic mammals using muskrats as the animal model. Muskrat (Ondatra zibethicus) has a sensitive VNO system that activates seasonal breeding behaviors through receiving specific substances, including pheromones and hormones. Vomeronasal organ receptor type 1 (V1R) and type 2 (V2R) and estrogen receptor α and ß (ERα and ERß) were found in sensory epithelial cells, non-sensory epithelial cells and lamina propria cells of the female muskrats' VNO. V2R and ERα mRNA levels in the VNO during the breeding period declined sharply, in comparison to those during the non-breeding period, while V1R and ERß mRNA levels were detected reversely. Additionally, transcriptomic study in the VNO identified that differently expressed genes might be related to estrogen signal and metabolic pathways. These findings suggested that the seasonal structural and functional changes in the VNO of female muskrats with different reproductive status and estrogen was regulated through binding to ERα and ERß in the female muskrats' VNO.

Seasonal expressions of COX-1, COX-2, and EP4 in the scent glands of muskrats (Ondatra zibethicus).

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 nonbreeding periods. There were significant seasonal differences in the scent glandular mass, with higher values in the breeding season and relatively low in the nonbreeding season. PGE2, EP4, COX-1, and COX-2 have been immunolocalized in the scent glandular and epithelial cells in both breeding and nonbreeding 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 nonbreeding 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. In addition, the transcriptomic study in the scent glands identified that differentially expressed genes might be related to fatty carboxylic monocarboxylic acid, steroidogenic-related pathways, and prostanoid metabolic processes. 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.

Identification of a distinct tumor endothelial cell-related gene expression signature associated with patient prognosis and immunotherapy response in multiple cancers.

BACKGROUND: Tumor endothelial cells (TECs) play a significant role in regulating the tumor microenvironment, drug response, and immune cell activities in various cancers. However, the association between TEC gene expression signature and patient prognosis or therapeutic response remains poorly understood. METHODS: We analyzed transcriptomics data of normal and tumor endothelial cells obtained from the GEO database to identify differentially expressed genes (DEGs) associated with TECs. We then compared these DEGs with those commonly found across five different tumor types from the TCGA database to determine their prognostic relevance. Using these genes, we constructed a prognostic risk model integrated with clinical features to develop a nomogram model, which we validated through biological experiments. RESULTS: We identified 12 TEC-related prognostic genes across multiple tumor types, of which five genes were sufficient to construct a prognostic risk model with an AUC of 0.682. The risk scores effectively predicted patient prognosis and immunotherapeutic response. Our newly developed nomogram model provided more accurate prognostic estimates of cancer patients than the TNM staging method (AUC = 0.735) and was validated using external patient cohorts. Finally, RT-PCR and immunohistochemical analyses indicated that the expression of these 5 TEC-related prognostic genes was up-regulated in both patient-derived tumors and cancer cell lines, while depletion of the hub genes reduced cancer cell growth, migration and invasion, and enhanced their sensitivity to gemcitabine or cytarabine. CONCLUSIONS: Our study discovered the first TEC-related gene expression signature that can be used to construct a prognostic risk model for guiding treatment options in multiple cancers.

Seasonal changes in endoplasmic reticulum stress and ovarian steroidogenesis in the muskrats (Ondatra zibethicus).

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), 17ß-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, 3ß-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 3ß-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.

Prognostic Significance of a Model Based on Acetaldehyde Dehydrogenase 2 Genetic Polymorphisms in Laryngeal Carcinoma.

OBJECTIVE: Because of the high costs associated with early-stage laryngeal carcinoma diagnosis and prognosis prediction, this study attempts to find valuable targets to establish a novel predictive model by focusing on the aldehyde dehydrogenase 2 (ALDH2) genotype and other peripheral blood markers. STUDY DESIGN: Retrospective study. SETTING: Tertiary comprehensive hospital. METHODS: From January 2011 to January 2021, 362 cases of laryngeal carcinoma were included and divided into 2 groups in this retrospective analysis. Information on medical history, alcohol, and tobacco consumption habits, ALDH2 genotypes, and other peripheral blood markers was collected. Endpoints of the current study included disease-free survival and overall survival. A nomogram model for overall survival was established and evaluated using receiver operating characteristic (ROC) curves. RESULTS: A total of 236 patients were included in the training cohort, and the other 126 were included in the validation cohort. The median follow-up of the patients was 9.6 years (interquartile range: 7.5-12.5 years). Peripheral fibrinogen, hemoglobin, and ALDH2 genotypes were significantly associated with an increase in laryngeal carcinoma mortality rate on Kaplan-Meier curves. The ROC curve showed that the effectiveness of overall survival prediction by the nomogram model was better than that of traditional clinical staging. CONCLUSION: A prognostic nomogram of laryngeal carcinoma patients involving ALDH2 and peripheral blood markers and T and N stages was constructed and validated.

Mass Spectrometry Imaging of Lipids in the Scent Glands of Muskrat (Ondatra zibethicus) in Different Reproductive Statuses.

As a typical seasonal breeding animal, male muskrats have a pair of scent glands that can emit musky odor substances to attract females during the breeding period. The present study aimed to visualize the differences in the distribution of lipids in the scent glands of muskrats during their different reproductive statuses by imaging mass spectrometry and quantitative real-time PCR (qRT-PCR). The results revealed remarkable differences in the expression and spatial distribution of lipids detected in the scent glands of muskrats during the different reproductive statuses. In addition, the expression levels of lipid molecules PC (32:0) and LysoPC (16:0) were found to be significantly higher in the breeding season than in the non-breeding season. Moreover, the mRNA expression levels of lipid synthesis enzyme Pemt and Pla2g4b were higher in the breeding season than in the non-breeding season, and there were positive correlations between the expression intensities of lipid molecules and the expression levels of Pemt and Pla2g4b. The present study investigates the changes and distribution of the endogenous lipid in the scent glands of muskrats and elucidates that the seasonal changes in the lipid metabolism may affect the functions of the scent glands in muskrats.

The effect of 3-Methyl-4-Nitrophenol on the early ovarian follicle development in mice by disrupting the clock genes expression.

3-Methyl-4-Nitrophenol (PNMC) is the main degradation product of organophosphate insecticide fenitrothion and a major component of diesel exhaust particles, which is now becoming a widely spread environmental endocrine disruptor. Previous reports showed PNMC exposure can affect the female reproductive system and ovarian function; however, the mechanism remains unclear. The main purpose of this study is to clarify the mechanism underlying the adverse effects of neonatal PNMC treatment on ovarian functions. The neonatal female mice were exposed to 10 mg/kg PNMC and the ovaries were collected on the 7th day after birth. The changes of follicular composition in mice ovaries were analyzed by histological staining, which showed that the proportion of primordial follicles in the ovaries treated by PNMC decreased, while the proportion of secondary follicles increased. The ovarian function was also investigated by detecting the expressions of steroidogenic enzymes (Star, Cyp11a1, Hsd3b1, Cyp17a1, Cyp19a1), gonadotropin receptors (Fshr and Lhr), androgen receptor (Ar), and estrogen receptors (Esr1 and Esr2) by immunohistochemistry or/and real-time quantitative PCR. The expression of Hsd3b1, Cyp17a1 and Esr2 were increased significantly in the PNMC exposed ovaries. Moreover, the expression patterns of clock genes (Bmal1, Clock, Per1, Per2, Cry1, Cry2 and Nr1d1) were disrupted in the ovaries after PNMC exposure. Furthermore, either the expression of DNA Methyltransferase Dnmt3b, or the methylation ratio of CpG islands in the upstream of Cry1 promoter regions were significantly decreased in PNMC exposed ovaries. Altogether, these results indicate that PNMC exposure affects follicle development and ovarian function by interfering with the epigenetic modification and disrupting the expression of clock genes.

Expression of glycogenic genes in the oviduct of Chinese brown frog (Rana dybowskii) during pre-brumation.

The oviduct of Chinese brown frog (Rana dybowskii) displays seasonal morphological and functional changes, which expands specifically during pre-brumation. To uncover the molecular mechanism underlying this phenomenon, we firstly confirmed the increased weight and enlarged diameter of the oviduct in pre-brumation by morphological observation. Interestingly, the glycogen content in the oviduct increased significantly during pre-brumation, indicating Rana dybowskii stores energy in the oviduct before brumation. Transcriptome analysis further identified the differentially expressed genes in the synthesis and metabolism pathways of carbohydrates in the oviduct during pre-brumation. Based on that evidence, we focused on the mRNA and protein expression of glycogenic genes in the oviduct of Rana dybowskii. qPCR confirmed that the expression of glycolysis and glycogenesis-related genes were up-regulated while gluconeogenesis-related genes were down-regulated during pre-brumation. Western blot data showed that glucose transporter GLUT1 and glycogen synthesis-regulation proteins including GYS, and p-GSK-3ß were highly expressed in the oviduct during pre-brumation. Moreover, immunohistochemical data showed that GLUT1, GYS, p-GYS, GSK-3ß and p-GSK-3ß were expressed regionally in the oviduct of Rana dybowskii. The data suggests that glycogen synthesis may be involved in the oviductal expansion of Rana dybowskii during the pre-brumation.

Estrogen signaling regulates seasonal changes of the prostate in wild ground squirrels (Spermophilus dauricus).

Previous studies found that testosterone was converted to dihydrotestosterone under the catalysis of 5α-reductase in the prostate of the wild ground squirrels. As a result, this study explored further whether testosterone could be converted to estrogen to affect the prostate gland function in wild ground squirrels. Histological observation showed that the area of epithelial cells and the prostatic secretory lumen were enlarged significantly during the breeding period. Transcriptome analysis revealed that the differentially expressed genes in the prostate were concentrated in the estrogen signaling pathway. Immunohistochemical analysis showed that the immunoreactivities of P450arom were detected in the stromal cells during the breeding and non-breeding periods, indicating the possible conversion of androgen into estrogen locally. Moreover, the immunolocalizations of ERα and ERß were detected mainly in the epithelial or stromal cells. Additionally, qPCR analysis displayed that the mRNA expression level of P450arom in the prostate was significantly higher during the breeding period than that in the non-breeding period. Consistently, the concentration of 17ß-estradiol (E2) was higher in the prostate during the breeding period than the non-breeding period, which is positively correlated with the seasonal changes of prostatic weight. In conclusion, the present results indicated that estrogen produced by P450arom presented in stromal cells might regulate the growth and function of the prostate gland via the locally expressed estrogen receptors in wild ground squirrels. The results of this study were momentous for further uncovering the mechanism of the seasonal regulated by signal pathways in the prostate of wild ground squirrels.

Seasonal expressions of ERα, ERß, EGF, EGFR, PI3K and Akt in the scent glands of the muskrats (Ondatra zibethicus).

Epidermal growth factor (EGF) is an important autocrine and/or paracrine mediator of steroid hormones to stimulate growth and differentiation in mammals. The aim of this study is to investigate seasonal expressions of estrogen receptor α (ERα), estrogen receptor ß (ERß), EGF, epidermal growth factor receptor (EGFR), phosphatidylinositol 3-kinase (PI3K) and protein kinase B (Akt) in the scent glands of the muskrats during the breeding and non-breeding seasons. Histologically, three types of cells including the glandular cells, interstitial cells and epithelial cells were identified in the scent glands in both seasons. Immunohistochemical results showed that ERα, ERß, EGF, EGFR, PI3K and Akt were presented in the different types of cells of the scent glands during the breeding and non-breeding seasons. Transcriptome data of the scent glandular tissues from muskrats in the breeding and non-breeding seasons showed that differential seasonal changes might be related to the estrogen-EGFR signaling pathway. The gene expression levels of ERα, ERß, EGF, EGFR, PI3K were increased, while the gene expression level of Akt were decreased in the breeding season than those in the non-breeding season. Besides, the concentrations of 17ß-estradiol (E2) in the serum and the scent glandular tissues were remarkably higher in the breeding season than those of the non-breeding season. Taken together, our results suggested that EGFR signaling pathway may coordinate with ERs signaling to regulate the seasonal changes of the scent glandular functions.

Seasonal expressions of VEGF and its receptors VEGFR1 and VEGFR2 in the prostate of the wild ground squirrels (Spermophilus dauricus).

As a vital male accessory reproductive gonad, the prostate requires vascular endothelial growth factors for promoting its growth and development. In this study, we investigated the localizations and expressions of vascular endothelial growth factor (VEGF) and its receptors including VEGF-receptor1 (VEFGR1) and VEGF-receptor2 (VEGFR2) in the prostate of the wild ground squirrels during the breeding and the non-breeding seasons. The values of total prostate weight and volume in the breeding season were higher than those in the non-breeding season. Histological observations showed that the exocrine lumens of the prostate expanded in the breeding season and contracted in the non-breeding season. The mRNA expression levels of VEGF and VEGFR2 in the prostate were higher in the breeding season than those in the non-breeding season, but the mRNA expression level of VEGFR1 had no significant change between the breeding and non-breeding seasons. Immunohistochemical results revealed that VEGF, VEGFR1 and VEGFR2 were presented in epithelial and stromal cells during the breeding and non-breeding seasons. In addition, the microvessels of the prostate were widely distributed and the number of microvessels increased obviously in the breeding season, while decreased sharply in the non-breeding season. These results suggested that expression levels of VEGF and VEGFR2 might be correlated with seasonal changes in morphology and functions of the prostate, and VEGF might serve as pivotal regulators to affect seasonal changes in the prostate functions of the wild male ground squirrels via an autocrine/paracrine pathway.

Seasonal expressions of SF-1, StAR and P450scc in the scent glands of the muskrats (Ondatra zibethicus).

The steroidogenesis occurs in specific cells and tissues in the mammals which begins with the transfer and intracellular processing of cholesterol converted to pregnenolone. This study investigated the gene and protein expression levels of steroidogenic factor 1 (SF-1), steroidogenic acute regulatory protein (StAR) and cytochrome P450 cholesterol side-chain cleavage enzyme (P450scc) in the scent glands of the muskrats during the breeding and non-breeding seasons. The immunohistochemical localizations of StAR and P450scc were identified in the glandular cells and epithelial cells while SF-1 was only expressed in glandular cells during the breeding and non-breeding seasons. The gene and protein expression levels of SF-1, StAR and P450scc in the scent glands were remarkedly higher in the breeding season than those of the non-breeding season. The interaction of micro RNAs (miRNAs) and transcriptome results showed that miR-762 and miR-4454 might be the genes encoding (Nr5a1, Star and Cyp11a1) in key biological processes. Taken together, these results suggested that the scent glands of the muskrats potentially owned ability to synthesize steroid hormones de novo, and the steroid hormones might affect the scent glandular functions of the muskrats during the breeding and non-breeding seasons.

Footedness predicts escape performance in a passerine bird.

Behavioral lateralization, which is associated with the functional lateralization of the two brain hemispheres, commonly exists in animals and can provide an individual with benefits such as enhanced cognition and dual tasking. Lateral bias in limb use, as a type of behavioral lateralization, occur in many species, but the reasons for the coexistence of left- and right-biased individuals in a population remain poorly understood. We examined the footedness of male yellow-bellied tits (Pardaliparus venustulus) when they used feet to clamp mealworms against a perch, and tested its association with other fitness-related behavioral traits (i.e., feeding efficiency, exploration tendency, and escape performance). We expected differently footed individuals to have respective advantages in these behaviors and thereby coexist ("respective advantage" hypothesis). We found their footedness repeatable, and there was no population-level bias. While no associations of feeding efficiency and exploration tendency with footedness were detected, the right-footed individuals were found to be harder to catch than the other individuals. Future studies need to investigate the reasons for the right-footed individuals' superior escape performance. Moreover, the escape advantage for being right-footed and the lack of population-level bias in footedness in male yellow-bellied tits suggest that the benefits related to left footedness also remain to be explored.