Publications by authors named "Pengyun Ji"

Background/objectives: Climate change-induced temperature elevations pose significant challenges to livestock reproduction, particularly affecting testicular function in small ruminants. This study investigates the acute heat-stress response in goat Sertoli cells (SCs), aiming to elucidate the molecular mechanisms underlying heat-induced damage to male reproductive tissues.

Methods: SCs were isolated from testes of 4-month-old black goats and exposed to heat stress (44 °C for 2.

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  • The study explored how cholestasis affects sperm production in mice, revealing that it harms testicular structure and function by lowering key gene expressions related to testosterone synthesis.
  • Researchers found that cholestasis disrupts liver metabolism of tryptophan, leading to reduced levels of important metabolites that influence androgen synthesis.
  • They identified a gut microbiota-testis connection related to cholestasis that affects male fertility, suggesting that targeting this axis could help prevent or treat male infertility linked to cholestasis.
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  • The study investigates the effects of Alpha-Ketoglutarate (AKG) on cumulus oocyte complexes (COCs) during in vitro maturation (IVM), highlighting its dose-dependent benefits and drawbacks.
  • At an optimal concentration of 30 µM, AKG enhances cumulus expansion, oocyte quality, and embryo development by reducing oxidative stress and improving mitochondrial function.
  • Conversely, a higher concentration of 750 µM negatively impacts these processes, although GDF9 supplementation can counteract some of the adverse effects caused by higher AKG levels.
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Genomic Safe Harbors (GSH) are loci used for the insertion of exogenous genetic elements, enabling exogenous gene expressing predictably without alterations of the host genome. These sites are becoming increasingly important as the gene editing technologies advance rapidly. Currently, only a few GSHs have been identified in the pig genome.

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  • Porcine oocytes have low in vitro maturation efficiency, but melatonin, produced by mitochondria in these oocytes, may enhance their quality and maturation by reducing reactive oxygen species (ROS) and increasing ATP production.
  • Knocking down melatonin production with siRNA leads to abnormal mitochondrial distribution and decreased ATP, hindering oocyte maturation, but these issues can be fixed with melatonin supplementation.
  • The beneficial effects of melatonin are likely mediated by its membrane receptors, as indicated by the blocking effects of the antagonist Luzindole, highlighting the mitochondrial role in melatonin synthesis for improved oocyte maturation.
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The placenta, as a "transit station" between mother and fetus, has functions delivering nutrients, excreting metabolic wastes and secreting hormones. A healthy placenta is essential for fetal growth and development while the melatonergic system seems to play a critical physiological role in this organ since melatonin, its synthetic enzymes and receptors are present in the placenta. In current study, Mtnr1a and Mtnr1b knockout mice were constructed to explore the potential roles of melatonergic system played on the placental function and intrauterine growth retardation (IUGR).

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The negative energy balance occurring in the periparturient period of cows will impede their health and postpartum performance. To target this issue, L-tryptophan was supplied to the prepartum cows. The results showed that L-tryptophan supplementation significantly increased the serum melatonin level and was accompanied with increases in SOD activity, IL-10 and colostrum IgA levels as well as decreases in MDA and IL-6 levels compared to the control cows.

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Objective: Maternal vitamin D deficiency is a prevalent public health issue worldwide. While isolated reports from certain cities in China have highlighted the existence of maternal vitamin D deficiency, no nationwide investigation has been conducted on this topic. Therefore, we conducted a meta-analysis and systematic review to examine the prevalence and associated influencing factors of maternal vitamin D deficiency in mainland China.

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Melatonin plays an important role in mammalian reproductive activities, to further understand the effects of endogenous melatonin on functions of ovary, the transgenic sheep with overexpression of melatonin synthetic enzyme gene ASMT in ovary were generated. The results showed that total melatonin content in follicular fluid of transgenic sheep was significantly greater than that in the wild type. Accordingly, the follicle numbers of transgenic sheep were also significantly greater than those in the WT.

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Beijing You Chicken, a valuable local chicken breed from Beijing, China, was once listed as an endangered breed. From the point of view of conservation, the preservation of this breed is an important task for the local researchers. Semen cryopreservation is a popular method to maintain valuable species.

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Embryo vitrification technology is widely used in livestock production, but freezing injury has been a key factor hindering the efficiency of embryo production. There is an urgent need to further analyze the molecular mechanism of embryo damage by the vitrification process. In the study, morulae were collected from Hu sheep uterine horns after superovulation and sperm transfusion.

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  • * The transgenic goats exhibited normal health parameters and improved milk quality, showing higher fat and dry matter content while having fewer somatic cells than wild-type goats.
  • * When injected with LPS to induce inflammation, the transgenic goats had enhanced immune responses and lower levels of pro-inflammatory cytokines compared to wild-type animals, indicating a potential improved resistance to pathogens.
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The diagnosis of ewes' pregnancy status at an early stage is an efficient way to enhance the reproductive output of sheep and allow producers to optimize production and management. The techniques of proteomics and metabolomics have been widely used to detect regulatory factors in various physiological processes of animals. The aim of this study is to explore the differential metabolites and proteins in the serum of pregnant and non-pregnant ewes by proteomics and metabolomics.

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  • Melatonin significantly influences reproductive activities in sheep and other mammals, and research focused on Hu sheep—known for their meat quality and prolific traits—examined the role of this hormone.
  • The study identified 68,673 SNPs linked to 1,126 genes through various analyses, finding that certain genotypes showed higher melatonin levels than the average.
  • Three specific SNPs associated with high melatonin production were pinpointed in key melatonin-related genes, suggesting they could be used as molecular markers to enhance reproductive traits in Hu sheep.
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In the current study, using and KO mice, we observed that the preservation of the melatonergic system is essential for successful early pregnancy in mice. We identified that aralkylamine N-acetyltransferase (AANAT), melatonin receptor 1A (MT1), and melatonin receptor 1B (MT2) were all expressed in the uterus. Due to the relatively weak expression of MT1 compared to AANAT and MT2, this study focused on AANAT and MT2.

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Previous studies have reported that the endogenous melatonin level is positively associated with the quality and yield of milk of cows. In the current study, a total of 34,921 SNPs involving 1,177 genes were identified in dairy goats by using the whole genome resequencing bulked segregant analysis (BSA) analysis. These SNPs have been used to match the melatonin levels of the dairy goats.

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In this study, the effects of daily melatonin supplementation (2 mg/kg) at the late gestational stage on the reproductive performance of the sows have been investigated. This treatment potentially increased the litter size and birth survival rate and significantly increased the birth weight as well as the weaning weight and survival rate of piglets compared to the controls. The mechanistic studies have found that these beneficial effects of melatonin are not mediated by the alterations of reproductive hormones of estrogen and progesterone, nor did the glucose and lipid metabolisms, but they were the results of the reduced oxidative stress in placenta associated with melatonin supplementation.

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Abstract: The transition of maternal to zygotic gene expression regulation is critical for human preimplantation embryo development. In recent years, single-cell RNA sequencing (scRNA-seq) had been applied to detect the factors that regulate human oocyte maturation and early embryo development. Here, the evaluation of transcriptomes in single blastomere from the embryo collected from patients by scRNA-seq was performed.

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Background: SCNT (somatic cell nuclear transfer) is of great significance to biological research and also to the livestock breeding. However, the survival rate of the SCNT cloned animals is relatively low compared to other transgenic methods. This indicates the potential epigenetic variations between them.

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  • * The study indicated that melatonin treatment enhanced levels of several key health indicators, such as growth hormone and immune factors, suggesting overall better growth and development.
  • * Further analysis suggested that melatonin may work by regulating genes related to apoptosis in muscle and fat tissues, as well as altering the gut microbiota, which could contribute to improved nutritional balance and growth in lambs.
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The yield efficiency of transgenic animal generation is relatively low[1]. To improve its efficiency has become a priority task for researchers[2]. Melatonin (N-acetyl-5-methoxytryptamine, MT) is a potent-free radical scavenger and antioxidant to protect mitochondria, lipids, protein and DNA from oxidative stress[3].

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Melatonin is a pleiotropic molecule with a variety of biological functions, which include its immunoregulatory action in mammals. Brucellosis is a worldwide endemic zoonotic disease caused by the Brucella, which not only causes huge economic losses for the livestock industry but also impacts human health. To target this problem, in current study, two marker-free transgenic sheep overexpressing melatonin synthetic enzyme ASMT (acetylserotonin O-methyltransferase) gene were generated and these melatonin enrich transgenic sheep were challenged by Brucella infection.

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  • Hypoxanthine (HX) inhibits oocyte maturation by raising cAMP levels, while melatonin (MT) counteracts this effect by lowering cAMP, potentially restoring meiosis.
  • In experiments, MT at concentrations of 10 M enhanced the inhibitory effect of HX on mouse oocyte maturation, but at higher doses, it alleviated the nuclear suppression and revived meiosis in young oocytes.
  • The study found that the melatonin receptor MT1 plays a crucial role in this process, as blocking it diminished the recovery of oocyte maturation, indicating that melatonin's protective effects against HX-induced inhibition occur through this receptor.
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Lipid is a crucial energy resource for mammalian oocyte. Melatonin could benefit the maturation of porcine oocyte , but the related mechanism is not elucidated yet. In the current study, methods to monitor lipid metabolism in single live oocytes were firstly established using probes (Lipi-Blue and Lipi-Green).

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