Surveillance of SARS-CoV-2 at the Huanan Seafood Market.

SARS-CoV-2, the causative agent of COVID-19, emerged in December 2019. Its origins remain uncertain. It has been reported that a number of the early human cases had a history of contact with the Huanan Seafood Market. Here we present the results of surveillance for SARS-CoV-2 within the market. From January 1st 2020, after closure of the market, 923 samples were collected from the environment. From 18th January, 457 samples were collected from 18 species of animals, comprising of unsold contents of refrigerators and freezers, swabs from stray animals, and the contents of a fish tank. Using RT-qPCR, SARS-CoV-2 was detected in 73 environmental samples, but none of the animal samples. Three live viruses were successfully isolated. The viruses from the market shared nucleotide identity of 99.99% to 100% with the human isolate HCoV-19/Wuhan/IVDC-HB-01/2019. SARS-CoV-2 lineage A (8782T and 28144C) was found in an environmental sample. RNA-seq analysis of SARS-CoV-2 positive and negative environmental samples showed an abundance of different vertebrate genera at the market. In summary, this study provides information about the distribution and prevalence of SARS-CoV-2 in the Huanan Seafood Market during the early stages of the COVID-19 outbreak.

Antigravity Autonomous Superwettable Pumps for Spontaneous Separation of Oil-Water Emulsions.

Oil-water separation based on superwettable materials offers a promising way for the treatment of oil-water mixtures and emulsions. Nevertheless, such separation techniques often require complex devices and external energy input. Therefore, it remains a great challenge to separate oil-water mixtures and emulsions through an energy-efficient, economical, and sustainable way. Here, a novel approach demonstrating the successful separation of oil-water emulsions using antigravity-driven autonomous superwettable pumps is presented. By transitioning from traditional gravity-driven to antigravity-driven separation, the study showcases the unprecedented success in purifying oil/water from emulsions by capillary/siphon-driven superwettable autonomous pumps. These pumps, composed of self-organized interconnected channels formed by the packing of superhydrophobic and superhydrophilic sand particles, exhibit outstanding separation flux, efficiency, and recyclability. The findings of this study not only open up a new avenue for oil-water emulsion separation but also hold promise for profound impacts in the field.

Experimental Investigation of Uncertainty Relations for Non-Hermitian Operators.

Uncertainty relations for Hermitian operators have been confirmed through many experiments. However, previous experiments have only tested the special case of non-Hermitian operators, i.e., uncertainty relations for unitary operators. In this study, we explore uncertainty relations for general non-Hermitian operators, which include Hermitian and unitary operators as special cases. We perform experiments with both real and complex non-Hermitian operators for qubit states, and confirm the validity of the uncertainty relations within the experimental error. Our results provide experimental evidence of uncertainty relations for non-Hermitian operators. Furthermore, our methods for realizing and measuring non-Hermitian operators are valuable in characterizing open-system dynamics and enhancing parameter estimation.

Day and Night Reversed Feeding Aggravates High-Fat Diet-Induced Abnormalities in Intestinal Flora and Lipid Metabolism in Adipose Tissue of Mice.

BACKGROUND: The incongruity between dietary patterns and the circadian clock poses an elevated risk for metabolic health issues, particularly obesity and associated metabolic disorders. The intestinal microflora engages in regulating various physiological functions of the host through its metabolites. OBJECTIVES: This study aimed to investigate the impact of reversed feeding schedules during the day and night on intestinal flora and lipid metabolism in high-fat diet-induced obese mice. METHODS: Mice aged 8-10 wk were subjected to either daytime or nighttime feeding and were administered a control or high-fat diet for 18 wk. At the end of the experiment, various assessments were conducted, including analysis of serum biochemic indices, histologic examination, evaluation of gene and protein expression in adipose tissue, and scrutiny of changes in intestinal microbial composition. RESULTS: The results showed that day-night reversed feeding caused an increase in fasting blood glucose and exacerbated the high-fat diet-induced weight gain and lipid abnormalities. The mRNA expression levels of Leptin and Dgat1 were increased by day-night reversed feeding, which also reduced the expression level of adiponectin under the high-fat diet. Additionally, there was a significant increase in the protein concentrations of PPARγ, SREBP1c, and CD36. Inverted feeding schedules led to a reduction in intestinal microbial diversity, an increase in the abundance of inflammation-related bacteria, such as Coriobacteriaceae_UCG-002, and a suppression of beneficial bacteria, including Akkermansia, Candidatus_Saccharimonas, Anaeroplasma, Bifidobacterium, Carnobacterium, and Odoribacter. Acinetobacter exhibited a significant negative correlation with Leptin and Fasn, suggesting potential involvement in the regulation of lipid metabolism. CONCLUSIONS: The results elucidated the abnormalities of lipid metabolism and intestinal flora caused by day-night reversed feeding, which exacerbates the adverse effects of a high-fat diet on lipid metabolism and intestinal microflora. This reversal in feeding patterns may disrupt both intestinal and lipid metabolism homeostasis by altering the composition and abundance of intestinal microflora in mice.

Musashi-2 potentiates colorectal cancer immune infiltration by regulating the post-translational modifications of HMGB1 to promote DCs maturation and migration.

Post-translational modifications (PTMs) of the non-histone protein high-mobility group protein B1 (HMGB1) are involved in modulating inflammation and immune responses. Recent studies have implicated that the RNA-binding protein (RBP) Musashi-2 (MSI2) regulates multiple critical biological metabolic and immunoregulatory functions. However, the precise role of MSI2 in regulating PTMs and tumor immunity in colorectal cancer (CRC) remains unclear. Here, we present data indicating that MSI2 potentiates CRC immunopathology in colitis-associated colon cancer (CAC) mouse models, cell lines and clinical specimens, specifically via HMGB1-mediated dendritic cell (DC) maturation and migration, further contributes to the infiltration of CD4+ and CD8+ T cells and inflammatory responses. Under stress conditions, MSI2 can exacerbate the production, nucleocytoplasmic transport and extracellular release of damage-associated molecular patterns (DAMPs)-HMGB1 in CRC cells. Mechanistically, MSI2 mainly enhances the disulfide HMGB1 production and protein translation via direct binding to nucleotides 1403-1409 in the HMGB1 3' UTR, and interacts with the cytoplasmic acetyltransferase P300 to upregulate its expression, further promoting the acetylation of K29 residue in HMGB1, thus leading to K29-HMGB1 nucleocytoplasmic translocation and extracellular release. Furthermore, blocking HMGB1 activity with glycyrrhizic acid (Gly) attenuates MSI2-mediated immunopathology and immune infiltration in CRC in vitro and in vivo. Collectively, this study suggests that MSI2 may improve the prognosis of CRC patients by reprogramming the tumor immune microenvironment (TIME) through HMGB1-mediated PTMs, which might be a novel therapeutic option for CRC immunotherapy.

Unique Fluorescence of Aggregation-Induced Emission Luminogens on Solid Surfaces Modified by Silicone Nanofilaments.

Aggregation-induced emission (AIE) has revolutionized solid-state fluorescence by overcoming the limitations of aggregation-caused quenching. While extensively studied in solutions, AIE's potential on solid surfaces remains largely unexplored, which can be fundamentally interesting and practically useful. In this work, we demonstrate the successful dispersion of tetraphenylethylene (TPE), one of the most classical AIE luminogens, on solid surfaces coated with silicone nanofilaments (SNF). The high surface area of SNF enables the uniform immobilization of TPE luminogens, replicating their dispersal behavior in solutions. Compared to unmodified surfaces, TPE dispersed on SNF-coated surfaces exhibits significantly enhanced fluorescence intensity. Moreover, a fascinating dynamic blue shift in TPE emission on SNF-coated surfaces is observed, with the velocity controllable by the surface group of SNF by up to 4 orders of magnitude, showing that TPE can be applied to the judgment of the nanoscale morphology and surface free energy of the solid surface. Owing to the superhydrophobicity and self-cleaning properties of SNF, the on-surface fluorescence can be sustained underwater and is resistant to dust contamination and rain erosion, with potential applications of information encryption presented. Our approach of uniformly dispersing AIE luminogens on nanomaterials with high surface areas provides a general methodology for creating on-surface fluorescence and saving the usage of expensive AIE luminogens in applications.

[Total polyphenols of Cydonia oblonga inhibited proliferation and migration of renal cancer cells by PI3K/Akt/mTOR pathway].

The mechanism of total polyphenols of Cydonia oblonga Miller(TPCOM) against kidney cancer was elucidated through a combination of network pharmacology, bioinformatics, and experimental verification. The active polyphenolic compounds from C. oblonga were screened by network pharmacological techniques and kidney cancer-related targets were collected through the database. The differential gene expression analysis was performed on RNA sequencing data from tumor tissue and normal tissue of kidney cancer patients obtained from the Gene Expression Omnibus(GEO) database. The results of network pharmacology predictions and differential gene expression analysis were used to identify the core genes targeted by TPCOM in kidney cancer. Survival analysis was conducted to identify key targets that could impact patient survival, followed by Kyoto Encyclopedia of Genes and Genomes(KEGG) and Gene Ontology(GO) enrichment analyses. Cell proliferation and activity experiments(cell counting kit-8) were conducted using TPCOM at concentrations ranging from 20 to 640 µg·mL~(-1) on 786-O and Renca cells. Additionally, TPCOM at concentrations of 40, 80, and 160 µg·mL~(-1) was applied to kidney cancer cells to assess its effect on cell migration and its regulation of protein expression levels related to the protein kinase B(Akt), mammalian target of rapamycin(mTOR), and phosphoinositide 3-kinase(PI3K) signaling pathways. Network pharmacology predicted eight active polyphenolic compounds from C. oblonga. Survival analysis revealed 15 significantly differentially expressed genes in kidney cancer that were affected by TPCOM and had a significant impact on patient survival. KEGG and GO analysis results indicated that these 15 targets were primarily associated with the PI3K/Akt signaling pathway, cell migration, and proliferation. The results showed that TPCOM could inhibit the proliferation of 786-O and Renca cells, with IC_(50) values of 121.4 and 137.9 µg·mL~(-1), respectively. TPCOM was also found to inhibit the migration of these cells and suppress the PI3K/Akt/mTOR signaling pathway. TPCOM may exert its anti-kidney cancer effects by inhibiting the activation of the PI3K/Akt/mTOR signaling pathway, thereby restraining the proliferation and migration of kidney cancer cells. This study provides a foundation for the research on the anti-tumor effects of natural product C. oblonga, particularly in Xinjiang, and holds significance for further promoting its development and utilization.

Electrochemical Visualization of Membrane Proteins in Single Cells at a Nanoscale Using Scanning Electrochemical Cell Microscopy.

The electrochemical visualization of proteins in the plasma membrane of single fixed cells was achieved with a spatial resolution of 160 nm using scanning electrochemical cell microscopy. The model protein, the carcinoembryonic antigen (CEA), is linked with a ruthenium complex (Ru(bpy)32+)-tagged antibody, which exhibits redox peaks in its cyclic voltammetry curves after a nanopipette tip contacts the cellular membrane. Based on the potential-resolved oxidation or reduction currents, an uneven distribution of membrane CEAs on the cells is electrochemically visualized, which could only be achieved previously using super-resolution optical microscopy. Compared with current electrochemical microscopy, the single-cell scanning electrochemical cell microscopy (SECCM) strategy not only improves the spatial resolution but also utilizes the potential-resolved current from the antibody-antigen complex to increase electrochemical imaging accuracy. Eventually, the electrochemical visualization of cellular proteins at the nanoscale enables the super-resolution study of cells to provide more biological information.

Musashi-2 Deficiency Triggers Colorectal Cancer Ferroptosis by Downregulating the MAPK Signaling Cascade to Inhibit HSPB1 Phosphorylation.

BACKGROUND: Musashi-2 (MSI2) is a critical RNA-binding protein (RBP) whose ectopic expression drives the pathogenesis of various cancers. Accumulating evidence suggests that inducing ferroptosis of tumor cells can inhibit their malignant biological behavior as a promising therapeutic approach. However, it is unclear whether MSI2 regulates cell death in colorectal cancer (CRC), especially the underlying mechanisms and biological effects in CRC ferroptosis remain elusive. METHODS: Experimental methods including qRT‒PCR, immunofluorescence, flow cytometry, western blot, co-immunoprecipitation, CCK-8, colony formation assay, in vitro cell transwell migration and invasion assays, in vivo xenograft tumor experiments, liver and lung CRC metastasis models, CAC mice models, transmission electron microscopy, immunohistochemistry, histopathology, 4D label-free proteomics sequencing, bioinformatic and database analysis were used in this study. RESULTS: Here, we investigated that MSI2 was upregulated in CRC and positively correlated with ferroptosis inhibitor molecules. MSI2 deficiency suppressed CRC malignancy by inhibiting cell proliferation, viability, migration and invasion in vitro and in vivo; and MSI2 deficiency triggered CRC ferroptosis by changing the intracellular redox state (ROS levels and lipid peroxidation), erastin induced cell mortality and viability, iron homeostasis (intracellular total irons and ferrous irons), reduced glutathione (GSH) levels and mitochondrial injury. Mechanistically, through 4D-lable free proteomics analysis on SW620 stable cell lines, we demonstrated that MSI2 directly interacted with p-ERK and MSI2 knockdown downregulated the p-ERK/p38/MAPK axis signaling pathway, which further repressed MAPKAPK2 and HPSB1 phosphorylation, leading to decreased expression of PCNA and Ki67 and increased expression of ACSL4 in cancer cells. Furthermore, HSPB1 could rescue the phenotypes of MSI2 deficiency on CRC ferroptosis in vitro and in vivo. CONCLUSIONS: This study indicates that MSI2 deficiency suppresses the growth and survival of CRC cells and promotes ferroptosis by inactivating the MAPK signaling pathway to inhibit HSPB1 phosphorylation, which leads to downregulation of PCNA and Ki67 and upregulation of ACSL4 in cancer cells and subsequently induces redox imbalance, iron accumulation and mitochondrial shrinkage, ultimately triggering ferroptosis. Therefore, targeted inhibition of MSI2/MAPK/HSPB1 axis to promote ferroptosis might be a potential treatment strategy for CRC.

Underwater Oleophobic Electrospun Membrane with Spindle-Knotted Structured Fibers for Oil-in-Water Emulsion Separation.

The potential of spider silk as an intriguing biological prototype for collecting water from a humid environment has attracted wide attention, and various materials with suitable structures have been engineered. Here, inspired by this phenomenon, a kind of superwetting poly(vinylidene fluoride) (PVDF) membrane with spindle-knotted structured fibers was prepared by the electrospinning method followed by oxygen plasma etching treatment. The prepared membrane presented a satisfactory separation efficiency for various oil-in-water emulsions. The cooperative effect of the special wettability property and the spindle-knot structure stimulated the emulsified oil droplets to accumulate quickly on the membrane surface. A model that explains the accumulation of emulsified oil droplets has also been developed. Furthermore, an artificial fiber comprising a micron-sized spindle-knot structure was prepared by the dip-coating method to clearly illustrate the aggregation process of the emulsified oil droplets and to verify the theoretical explanation. We hope that this study will provide new inspiration for oil/water emulsion separation techniques.

Dramatic Carbon Loss in a Permafrost Thaw Slump in the Tibetan Plateau is Dominated by the Loss of Microbial Necromass Carbon.

Thaw slumps can lead to considerable carbon loss in permafrost regions, while the loss of components from two major origins, i.e., microbial and plant-derived carbon, during this process remains poorly understood. Here, we provide direct evidence that microbial necromass carbon is a major component of lost carbon in a retrogressive permafrost thaw slump by analyzing soil organic carbon (SOC), biomarkers (amino sugars and lignin phenols), and soil environmental variables in a typical permafrost thaw slump in the Tibetan Plateau. The retrogressive thaw slump led to a ∼61% decrease in SOC and a ∼25% SOC stock loss. As evident in the levels of amino sugars (average of 55.92 ± 18.79 mg g-1 of organic carbon, OC) and lignin phenols (average of 15.00 ± 8.05 mg g-1 OC), microbial-derived carbon (microbial necromass carbon) was the major component of the SOC loss, accounting for ∼54% of the SOC loss in the permafrost thaw slump. The variation of amino sugars was mainly related to the changes in soil moisture, pH, and plant input, while changes in lignin phenols were mainly related to the changes in soil moisture and soil bulk density.

Construction of ceRNA Regulatory Network in Human Oocytes.

BACKGROUND: Cryogenic freezing, often known as cryopreservation, is a technique for preserving human oocytes. METHODS: In this study, differentially expressed long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) were identified using the human frozen oocyte dataset GSE69768 from the Gene Expression Database (GEO). Subsequently, combined with the microRNA atlas database, the miRNAs combined with differentially expressed lncRNAs (DElncRNAs) were predicted, and the lncRNA-miRNA-mRNA interaction relationship and competitive endogenous (ceRNA) regulatory network were obtained. RESULTS: The results revealed that multiple DElncRNAs and DEmRNAs were involved in the ceRNA network of the human oocyte. Finally, GO functional annotation and KEGG pathway enrichment analysis were performed on the differentially expressed mRNA (DEmRNA) in the ceRNA network, and the biological processes and pathways that may be related to the ceRNA network in frozen oocytes were explored. CONCLUSIONS: In conclusion, in the ceRNA network for human oocyte, lncRNA, mRNA, and miRNA do not each operate via a distinct, independent mechanism. Not only does the RNA-RNA contact involve the ceRNA regulatory mechanism, but it also involves interactions between proteins that are encoded by genes. Furthermore, the negative effects of inter-individual variations and instability on the quality of high-throughput detection cannot be completely ruled out due to the paucity of human oocyte data containing both mRNA and lncRNA expression profiles.

Promoting Active Aging Through Sports Participation: A Qualitative Exploration of Serious Leisure Among Older Chinese Adults.

China's population of older individuals reached 264.02 million in 2020, an increase of 5.44% from 2010. This study explores how participation in serious leisure sports, which have enduring benefits for older adults, contributes to active aging. In-depth interviews were conducted with 15 older participants aged 60-78 years who had participated in a leisure sport activity for 1 year or longer. A thematic analysis was conducted, and four themes emerged: body improvements, positive emotions, optimistic life attitudes, and social interactions. Older adults who participate in serious leisure sports are empowered via practice and learning opportunities to engage with their aging bodies, pursue psychological benefits, and jointly maintain leisure groups. The findings of this study contribute to our understanding of the "rights-based" approach to active aging and allow us to identify serious leisure sports as an active way for older adults to improve their quality of life.

Exploration of a new hepatitis a surveillance system in Beijing, China: based on molecular epidemiology.

BACKGROUND: The incidence of hepatitis A virus (HAV) infection is low in Beijing, China, but the risk of outbreaks still exists. It is difficult to identify possible sources of infection among sporadic cases based on a routine surveillance system. Therefore, a more effective surveillance system needs to be established. METHODS: The epidemiological data of hepatitis A were obtained from a routine surveillance system. Patients with HAV confirmed at the local hospitals were asked to complete a questionnaire that included additional case information and possible sources of infection. Serum and fecal specimens were also collected for testing HAV RNA by polymerase chain reaction. In addition, the 321-nucleotide segment of the VP1/2A junction region was sequenced to determine the HAV genotype. RESULTS: In 2019, 110 HAV cases were reported in Beijing, with an incidence rate of 0.51/100,000. 61(55.5%) of these patients were male. The greatest proportion of these patients were aged from 30 to 60 years. The rate was lower in suburban and rural areas compared to urban areas. Contaminated food consumption, particularly seafood consumption, was the primary potential source of infection. Among the 16 specimens of confirmed HAV cases that could be sequenced, 93.8% were HAV IA, and 6.3% were HAV IB. In addition, the samples collected from all HAV sequences in this investigation showed 89.4-100% nucleotide homology. Two groups (each with three sporadic cases) showed 100% nucleotide homology. The three sporadic cases in one group had the same possible source of infection: contaminated salad with raw vegetables and seafood. In the other group, the three sporadic cases did not have an epidemiological connection. CONCLUSIONS: In a low HAV prevalent area, such as in Beijing, incorporating molecular epidemiology into the routine surveillance system could help inform possible clusters of outbreaks and provide support for earlier control of HAV transmission. Nevertheless, increased sampling from detected cases and improved specimen quality are needed to implement such a system.

Usage of mobile health interventions among overweight/obese PCOS patients undergoing assisted reproductive technology treatment during the COVID-19 pandemic.

Objective: In the context of the coronavirus disease 2019 (COVID-19) pandemic, telemedicine is a promising tool for providing clinical care for patients. Since the first-line treatment for infertile women with polycystic ovarian syndrome (PCOS) is lifestyle modification, a mobile-based service that provides lifestyle modification education would be helpful in the treatment of PCOS patients. In this observational study, the effect of a mobile Health (mHealth) application for lifestyle modification on PCOS patients undergoing assisted reproductive technology (ART) treatment was evaluated.Methods: A total of 79 overweight/obese patients (40 in the paper group and 39 in the WeChat application group) with PCOS from the First Affiliated Hospital of University of Science and Technology of China were enrolled in the study. The changes in the outcomes of BMI and ART treatment were analyzed between the two groups.Results: After three months of intervention, the BMIs in the control and mHealth groups were 24.5 ± 3.3 and 23.7 ± 3.1, respectively. The percentage of patients who lost weight was higher in the WeChat group than in the control group (87.2% vs. 67.5%). Furthermore, PCOS patients in the WeChat group were found to have a higher live birth rate than those in the control group (p = 0.005).Conclusion: Lifestyle modifications for PCOS patients undergoing ART treatment using the WeChat application improved weight loss and oocyte quality. Infertile patients with PCOS were more likely to make lifestyle modifications based on the usage of mobile applications during the COVID-19 pandemic.

Per1/Per2 knockout Affects Spleen Immune Function in Elderly Mice via Inducing Spleen Lymphocyte Ferroptosis.

Disturbances in circadian rhythms are known to affect immune functions. However, the long-term impact of abnormal circadian rhythms on the immune-related functions of the spleen are poorly understood. Hence, we aimed to investigate the immune-related functions of spleen in Per1/Per2 double-knockout (DKO) and wild-type (WT) mice aged 4, 9, and 14 months. Compared to the WT mice, the DKO mice had smaller spleen white pulp (WP) and lymphocyte germinal area, as well as fewer immune cells with age-these differences were especially clear. The spleen lymphocyte mortality, malondialdehyde (MDA) levels, reactive oxygen species (ROS) levels, and ferritin-binding receptor (TFR1) levels were significantly higher in the 14-month-old DKO mice than in WT mice of the same age. Transcriptome analysis showed that most of the differentially expressed mRNAs were enriched in DNA damage repair-related pathways. In DKO mice, spleen cells showed up-regulation of pro-ferroptosis genes, such as Cd36,Atm, and Acsl4, and down-regulation of anti-ferroptosis genes, such as GPX4. We found that long-term abnormalities in the circadian rhythm can induce DNA damage and ferroptosis in mouse spleen.

The correlation between vitamin D, glucose homeostasis and androgen level among polycystic ovary syndrome patients: a cross-sectional study.

MATERIAL AND METHODS: A total of 290 women with PCOS participated in this cross-sectional study. Glucose homeostasis was assessed by a 75-g oral glucose tolerance test and the concentration of serum 25-hydroxy vitamin D was determined among all subjects. The homeostasis model assessment of insulin resistance (HOMA-IR) was taken as the indicator of insulin resistance. Beta cell function was estimated using the insulinogenic index and the disposition index. Free androgen index (FAI) was used to represent the androgen level. RESULTS: In our study, 7.2% of the patients had Vit D severe deficiency, 75.2% had Vit D deficiency and 15.5% had vit D insufficiency. The level of serum 25(OH)D showed a significant positive association with insulinogenic index (r = 0.147, p < .05), disposition index (r = 0.280, p < .05), and SHBG (r = 0.178, p < .05) but exhibited a negative association with HOMA-IR (r = -0.198, p < .05), FAI (r = -0.178, p < .05). Adjusted age and BMI, 25(OH)D would be the dependent variable on disposition index [B = 0.259, 95%CI(0.041,0.477)] and FAI [B = -0.125, 95%CI(-0.232, -0.017)]. CONCLUSIONS: According to our results, the low levels of serum 25(OH)D were common in women with PCOS, which was speculated to be associated with glucose homeostasis and the androgen level.

MAPK, AKT/FoxO3a and mTOR pathways are involved in cadmium regulating the cell cycle, proliferation and apoptosis of chicken follicular granulosa cells.

The occurrence of cadmium (Cd) in feed is a major problem in animal health and production. Studies have confirmed that Cd depresses egg production of laying hens, which is closely related to follicular atresia. This study aimed to assess the toxic impacts of Cd on the ovarian tissue, and to examine the mechanism of Cd-induced granulosa cell proliferation and apoptosis. Results from the nitric oxide (NO) and malondialdehyde (MDA) content, total superoxide dismutase (T-SOD), glutathione peroxide (GSH-Px), total nitric oxide synthase (T-NOS) and adenosine triphosphatase (ATPase) activities, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay, and hematoxylin-eosin (H & E) staining indicated that excess Cd induced oxidative stress, granulosa cell apoptosis and follicular atresia in the layer ovary. Low-dose Cd exposure (1 µM) induced the granulosa cell proliferation, upregulated the mRNA levels of RSK1 and RHEB, activated FoxO3a, AKT, ERK1/2, mTOR and p70S6K1 phosphorylation, and promoted cell cycle progression from phase G1 to S. However, high-dose Cd exposure (15 µM) induced reactive oxygen species (ROS) generation and cell apoptosis, upregulated the mRNA levels of the inflammatory factors, ASK1, JNK, p38 and TAK1, downregulated the expressions of RSK1 and RHEB genes, and inhibited the phosphorylation of ERK1/2, mTOR and p70S6K1 proteins, and the cell cycle progression. Rapamycin pre-treatment completely blocked the phosphorylation of mTOR and p70S6K1 proteins, and the cell cycle progression induced by 1 µM Cd, and accelerated 15 µM Cd-induced cell apoptosis and cell cycle arrest. The microRNA sequencing result showed that 15 µM Cd induced differential expression of microRNA genes, which may regulate AKT, ERK1/2 and mTOR signaling and cell cycle progression by regulating the activity of G proteins and cell cycle-related proteins. Conclusively, these results indicated that Cd can cause the ovarian damage and follicular atresia, and regulate cell cycle, cell proliferation or apoptosis of granulosa cells through MAPK, AKT/FoxO3a and mTOR pathways in laying hens.

Comparative Investigation into Formycin A and Pyrazofurin A Biosynthesis Reveals Branch Pathways for the Construction of C-Nucleoside Scaffolds.

Formycin A (FOR-A) and pyrazofurin A (PRF-A) are purine-related C-nucleoside antibiotics in which ribose and a pyrazole-derived base are linked by a C-glycosidic bond. However, the logic underlying the biosynthesis of these molecules has remained largely unexplored. Here, we report the discovery of the pathways for FOR-A and PRF-A biosynthesis from diverse actinobacteria and propose that their biosynthesis is likely initiated by a lysine N6-monooxygenase. Moreover, we show that forT and prfT (involved in FOR-A and PRF-A biosynthesis, respectively) mutants are correspondingly capable of accumulating the unexpected pyrazole-related intermediates 4-amino-3,5-dicarboxypyrazole and 3,5-dicarboxy-4-oxo-4,5-dihydropyrazole. We also decipher the enzymatic mechanism of ForT/PrfT for C-glycosidic bond formation in FOR-A/PRF-A biosynthesis. To our knowledge, ForT/PrfT represents an example of ß-RFA-P (ß-ribofuranosyl-aminobenzene 5'-phosphate) synthase-like enzymes governing C-nucleoside scaffold construction in natural product biosynthesis. These data establish a foundation for combinatorial biosynthesis of related purine nucleoside antibiotics and also open the way for target-directed genome mining of PRF-A/FOR-A-related antibiotics.IMPORTANCE FOR-A and PRF-A are C-nucleoside antibiotics known for their unusual chemical structures and remarkable biological activities. Deciphering the enzymatic mechanism for the construction of a C-nucleoside scaffold during FOR-A/PRF-A biosynthesis will not only expand the biochemical repertoire for novel enzymatic reactions but also permit target-oriented genome mining of FOR-A/PRF-A-related C-nucleoside antibiotics. Moreover, the availability of FOR-A/PRF-A biosynthetic gene clusters will pave the way for the rational generation of designer FOR-A/PRF-A derivatives with enhanced/selective bioactivity via synthetic biology strategies.

Chemoselective Hydrogenation of Nitroaromatics at the Nanoscale Iron(III)-OH-Platinum Interface.

Catalytic hydrogenation of nitroaromatics is an environment-benign strategy to produce industrially important aniline intermediates. Herein, we report that Fe(OH)x deposition on Pt nanocrystals to give Fe(OH)x /Pt, enables the selective hydrogenation of nitro groups into amino groups without hydrogenating other functional groups on the aromatic ring. The unique catalytic behavior is identified to be associated with the FeIII -OH-Pt interfaces. While H2 activation occurs on exposed Pt atoms to ensure the high activity, the high selectivity towards the production of substituted aniline originates from the FeIII -OH-Pt interfaces. In situ IR, X-ray photoelectron spectroscopy (XPS), and isotope effect studies reveal that the Fe3+ /Fe2+ redox couple facilitates the hydrodeoxygenation of the -NO2 group during hydrogenation catalysis. Benefitting from FeIII -OH-Pt interfaces, the Fe(OH)x /Pt catalysts exhibit high catalytic performance towards a broad range of substituted nitroarenes.