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770 result(s) for "Ju, Dan"
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The evolution of skin pigmentation-associated variation in West Eurasia
Skin pigmentation is a classic example of a polygenic trait that has experienced directional selection in humans. Genome-wide association studies have identified well over a hundred pigmentation-associated loci, and genomic scans in present-day and ancient populations have identified selective sweeps for a small number of light pigmentation-associated alleles in Europeans. It is unclear whether selection has operated on all of the genetic variation associated with skin pigmentation as opposed to just a small number of large-effect variants. Here, we address this question using ancient DNA from 1,158 individuals from West Eurasia covering a period of 40,000 y combined with genome-wide association summary statistics from the UK Biobank. We find a robust signal of directional selection in ancient West Eurasians on 170 skin pigmentation-associated variants ascertained in the UK Biobank. However, we also show that this signal is driven by a limited number of large-effect variants. Consistent with this observation, we find that a polygenic selection test in present-day populations fails to detect selection with the full set of variants. Our data allow us to disentangle the effects of admixture and selection. Most notably, a large-effect variant at SLC24A5 was introduced to Western Europe by migrations of Neolithic farming populations but continued to be under selection post-admixture. This study shows that the response to selection for light skin pigmentation in West Eurasia was driven by a relatively small proportion of the variants that are associated with present-day phenotypic variation.
Extraction Optimization of Phenolic Compounds from Triadica sebifera Leaves: Identification, Characterization and Antioxidant Activity
Triadica sebifera (T. sebifera) has attracted much attention because of the high oil content in its seeds, but there are few systematic studies on the phenolic compounds of T. sebifera leaves (TSP). In this study, the extraction process of TSP was optimized by response surface methodology. The phenolic components of these extracts were analyzed by high-performance liquid chromatography (HPLC). Moreover, the effects of hot air drying (HD), vacuum drying (VD) and freeze drying (FD) on the antioxidant activity and characterization of T. sebifera leaf extract (TSLE) were evaluated. Under the conditions of ethanol concentration 39.8%, liquid–solid ratio (LSR) 52.1, extraction time 20.2 min and extraction temperature 50.6 °C, the maximum TSP yield was 111.46 mg GAE/g dw. The quantitative analysis and correlation analysis of eight compounds in TSP showed that the type and content of phenolic compounds had significant correlations with antioxidant activity, indicating that tannic acid, isoquercitrin and ellagic acid were the main components of antioxidant activities. In addition, through DPPH and ABTS determination, VD-TSLE and FD-TSLE showed strong scavenging ability, with IC50 values of 138.2 μg/mL and 135.5 μg/mL and 73.5 μg/mL and 74.3 μg/mL, respectively. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) infrared spectroscopy revealed small differences in the extracts of the three drying methods. This study lays a foundation for the effective extraction process and drying methods of phenolic antioxidants from T. sebifera leaves, and is of great significance for the utilization of T. sebifera leaves.
Effects of Environmental and Spatial Variables on Bacteria in Zhanjiang Mangrove Sediments
The bottom mud of mangroves contains numerous microbial groups that play an important role in the main ecological functions of the mangrove ecosystem. The diversity and functional and environmental factors related to microbial communities, in terms of the assembly process and in environmental adaptation of the abundance and rare bacterial communities in the mangrove ecosystem, have not been fully explored. We used 16S high-throughput sequencing and operational taxonomic unit analysis to compare the diversity and composition of bacterial communities in different tidal zones in the sediments of the Zhanjiang Gaoqiao Mangrove Nature Reserve, compare the ecological adaptation thresholds and phylogenetic signals of bacterial communities under different environmental gradients, and examine the factors affecting the composition of the bacterial community. The diversity of microbial species and structure and function of the mangrove sediments were affected by the environment, showing the trend: mid tide zone > climax zone > low tide zone. Organic matter content, oxygen content, pH, and total phosphorus were identified as important environmental factors determining the functional diversity of bacterial communities and survival, while pH influences species evolution. The abundant taxa showed a wider response threshold and stronger phylogenetic signals of ecological preference across environmental gradients compared to rare taxa. The abundant bacterial groups have broader environmental adaptability than rare bacterial groups, and different environmental factors affect different communities and functions in the mangrove ecological environment. These results elucidate the mechanism underlying the generation and maintenance of bacterial diversity in response to global environmental changes.
Influence of Untreated and Microbially Degraded Mangrove Sediment Microplastics on Zebrafish (Danio rerio) Intestinal Histology and Immune and Antioxidant Biomarkers
MPs are pervasive pollutants in marine ecosystems, posing risks to aquatic organisms due to their small size and bioaccumulation potential. This study investigated the intestinal toxicity of MP particles extracted from mangrove sediments in zebrafish, comparing the effects before and after microbial degradation. Zebrafish were exposed to either undegraded MPs or microbially degraded MP extracts at concentrations of 0 (control), 2, 10, and 50 mg/L for 21 days in 10 L tanks (stocking density: 10 fish/L), with three replicate tanks per concentration. MPs were dispersed ultrasonically before addition to the water. Intestinal samples were collected on 7, 14, and 21 days for the analysis of immune response (tumor necrosis factor-alpha, TNF-α; interleukin-1 beta, IL-1β; interleukin-6, IL-6; interleukin-8, IL-8) and antioxidant activity (superoxide dismutase, SOD; catalase, CAT). Histopathological analysis revealed intestinal wall thinning, villus damage, and epithelial cell detachment in zebrafish exposed to both undegraded and degraded MP extracts; however, undegraded MPs induced more severe intestinal damage. Results indicated dynamic changes in cytokine expression: TNF-α decreased initially before increasing, while IL-1β and IL-8 first rose then declined. IL-6 peaked on day 7, dropped by day 14, and increased again on day 21. CAT expression decreased, whereas SOD increased only in the pre-degradation group. Microbial degradation reduced intestinal damage severity, with effects intensifying at higher MP exposure levels. These findings demonstrate that MPs can impair zebrafish digestive systems, but microbial degradation mitigates their toxicity. This study underscores the importance of biodegradation as a potential environmental remediation strategy and provides experimental evidence on MPs’ impact on aquatic organisms.
Repeated Restraint Stress Led to Cognitive Dysfunction by NMDA Receptor-Mediated Hippocampal CA3 Dendritic Spine Impairments in Juvenile Sprague-Dawley Rats
Although numerous studies have indicated that chronic stress causes cognitive dysfunction with the impairment of synaptic structures and functions, the relationship between cognitive deficits induced by repeated restraint stress and the level of NMDA-receptor in the subregion of hippocampus is still vague until now. In this study, 3-week-old male Sprague-Dawley rats were exposed to repeated restraint stress for 7 days consecutively, their cognitive functions were evaluated through behavioral tests, and then they were sacrificed for electrophysiological, morphological, and biochemical assays. Chronic repeated restraint stress led to cognitive and electrophysiological impairments, with a reduced density of dendritic spines. We also found that the protein level of NMDA receptors increased only in the hippocampal CA3 region. Nevertheless, repeated restraint stress-induced cognitive and synaptic dysfunction were effectively reversed byRo25-6981, an inhibitor of the GluN2B receptor. These findings suggest that repeated restraint stress-induced synaptic and cognitive deficits are probably mediated through NMDA receptor.
High Expression of IGFBP7 in Fibroblasts Induced by Colorectal Cancer Cells Is Co-Regulated by TGF-β and Wnt Signaling in a Smad2/3-Dvl2/3-Dependent Manner
Fibroblasts in the tumor microenvironment are a key determinant in cancer progression and may be a promising target for cancer therapy. Insulin-like growth factor binding protein 7 (IGFBP7) is known as a tumor suppressor in colorectal cancer (CRC). The present study investigated the inductive mechanism of IGFBP7 expression in fibroblasts by supernatant from the CRC cell line, SW620. The results showed that the expression of IGFBP7 was up-regulated in the fibroblasts when treated with SW620 supernatant and exogenous TGF-β1. The IGFBP7 induced by SW620 supernatant or TGF-β1 was partially inhibited by the TGF-β1 specific antibody AF and TGF-β1 receptor antagonist SB431542. The Wnt signaling-targeted genes, c-Myc, CCND1 and the proteins Dvl2/3, were all up-regulated in fibroblasts expressing high levels of IGFBP7, and the up-regulation could be inhibited both by the Wnt signaling antagonist Dickkopf-1 (DKK1) and by the TGF-β1 receptor antagonist SB431542. In conclusion, CRC cells promote the high expression of IGFBP7 in fibroblasts, most likely through the co-regulation of TGF-β and Wnt signaling in a Smad2/3-Dvl2/3 dependent manner. Taken together, these data suggest that the fibroblasts could be a novel therapeutic target in tumor therapy.
Symptomatic Postoperative Discal Pseudocyst After Percutaneous Endoscopic Interlaminar Discectomy: Case Report and Literature Review
Background A postoperative discal pseudocyst (PDP) is a cystic lesion that is formed in the operation area of the intervertebral disc, leading to recurrence or even worse symptoms. To our knowledge, to date, there is no research focusing specifically on PDP following percutaneous endoscopic interlaminar discectomy (PEID). Case presentation We present the case of a 27‐year‐old man with L5S1 intervertebral disc herniation who was treated with PEID after failed conservative treatment. His leg pain was relieved immediately but reoccurred on the 40th day. MRI showed a PDP. Because loxoprofen and bedrest were ineffective and the patient was anxious, we performed a cystectomy. The patient's symptoms were significantly relieved, and a 6‐month follow up showed no recurrence both clinically and on MRI. Conclusion A PDP is more likely to form using the interlaminar approach than the transforaminal approach. For patients with mental stress, severe pain, and neurological symptoms, surgery is suggested to remove the cyst. Discectomy cannot be performed when disc degeneration is mild. We present the case of a 27‐year‐old man with L5S1 intervertebral disc herniation who was treated with PEID after failed conservative treatment. His leg pain was relieved immediately but reoccurred on the 40th day. MRI showed a PDP. Because loxoprofen and bed rest were ineffective and the patient was anxious, we performed a cystectomy. The patient's symptoms were significantly relieved, and a 6‐month follow‐up showed no recurrence both clinically and on MRI.
Chemical Composition and Antioxidant Activity of Zanthoxylum armatum Leaves in Response to Plant Age, Shoot Type and Leaf Position
Zanthoxylum armatum (Z. armatum) leaves represent more than 50% of by-products with promising potential applications, and there are still largely unknown variations in chemical composition and antioxidant activity in its leaves. In the present study, the changes in carbon (C), nitrogen (N) and phosphorous (P), soluble protein (SP), amino acid (AA), soluble sugar (SS), total phenol (TP) and total flavonoids (TF) content as well as antioxidant capacity in Z. armatum leaves from two plant ages between two shoot types and three leaf positions were investigated. Our results showed that there are significant effects of plant age, shoot type and leaf position and their interactions on almost all the tested parameters. Shoot types were the main factor affecting the accumulation of chemical compositions and antioxidant capacity, followed by leaf positions and plant ages. Shoot type and leaf position had stronger effects than plant age. Statistical analysis revealed a series of correlations between antioxidant capacity, TP and chemical elements. Z. armatum leaves, an agricultural by-product, showed significant differences in chemical composition and antioxidant activity in response to plant age, shoot type and leaf position, which can be valuable to incentive its cultivation management strategy and its better utilization for economic and environmental benefits.
Analysis of the Effects of Prey, Competitors, and Human Activity on the Spatiotemporal Distribution of the Wolverine (Gulo gulo) in a Boreal Region of Heilongjiang Province, China
Understanding how endangered carnivores partition spatiotemporal distribution in human-dominated landscapes is pivotal for mitigating biodiversity loss in climate-sensitive boreal ecosystems. Here, we used kernel density data derived from a 16-month camera-trap survey (140 UVL7 cameras), cold single-season (November–April) occupancy models, and MaxEnt 3.4.4 to identify the effects of biotic interactions, anthropogenic disturbance, and environmental factors on the spatiotemporal distribution of the wolverine (Gulo gulo) in Beijicun National Nature Reserve, Heilongjiang Province, China. We found that wolverines exhibited crepuscular activity patterns using night-time relative abundance index (NRAI) = 50.29% with bimodal peaks (05:00–07:00, 13:00–15:00), with dawn activity predominant during the warm season (05:00–06:00) and a bimodal activity pattern in the cold season (08:00–09:00, 14:00–15:00). Temporal overlap with prey (overlap coefficient Δ = 0.84) and competitors (Δ = 0.70) was high, but overlap with human-dominated temporal patterns was low (Δ = 0.58). Wolverines avoided human settlements and major roads, preferred moving along forest trails and gentle slopes, and avoided high-altitude deciduous forests. Populations were mainly concentrated in southern Hedong and Qianshao Forest Farms, which are characterized by high habitat integrity, high prey densities, and minimal anthropogenic disturbance. These findings suggest that wolverines may influence boreal trophic networks, especially in areas with intact prey communities, competitors, and spatial refugia from human disturbances. We recommend that habitat protection and management within the natural reserve be prioritized and that sustainable management practices for prey species be implemented to ensure the long-term survival of wolverines.
Chromolaena odorata as a potential feed additive bioresource to alleviate heat stress in chickens in the humid tropics
Chromolaena odorata (commonly known as Jack in the Bush, a thoroughwort of the Aster family) contains polyphenols and antioxidant enzymes that activate biology defence mechanisms and stress-sensing transcription factors to prevent oxidative damage and heat stress in chicken. Dietary inclusions of C. odorata leaf meal at 12%, and C. odorata crude flavonoids at 400 mg/kg/d have been shown to exert competitive exclusion effects to enhance gut eubiosis, humoral immunity, hypoglycaemia and metabolic functions necessary to attenuate oxidative stress in chickens. Ethanol extract of the plant at 25-400 µg/ml showed a strong antioxidant capacity in vitro, similar to 10-80 µg/ml standard ascorbic acid administration. Chromomoric acid C-1 from C. odorata methanol extract, at 10 µg, demonstrated anti-inflammatory potential by activating Nrf2 and suppressing NF-κB in a luciferase reporter assay at an inhibition capacity (IC 50 ) of 6.9 µM. These biological defence properties of this plant have the potential to maintain microbial homeostasis and gut integrity, enhance antioxidative physiology for cellular oxidative balance, and mitigate oxidative damage in the presence of heat stress. The invasive nature of the plant in the humid tropics makes it a readily available and a cheap bioresource. Hepatotoxic, mutagenic and cytotoxic evaluations suggested that the aerial parts of the herbal plant are safe for use in animal nutrition.