The circadian clock plays a critical role in regulating various physiological processes, including gene expression, metabolic regulation, immune response, and the sleep-wake cycle in living organisms. Post-translational modifications (PTMs) are crucial regulatory mechanisms to maintain the precise oscillation of the circadian clock. By modulating the stability, activity, cell localization and protein-protein interactions of core clock proteins, PTMs enable these proteins to respond dynamically to environmental and intracellular changes, thereby sustaining the periodic oscillations of the circadian clock. Different types of PTMs exert their effects through distincting molecular mechanisms, collectively ensuring the proper function of the circadian system. This review systematically summarized several major types of PTMs, including phosphorylation, acetylation, ubiquitination, SUMOylation and oxidative modification, and overviewed their roles in regulating the core clock proteins and the associated pathways, with the goals of providing a theoretical foundation for the deeper understanding of clock mechanisms and the treatment of diseases associated with circadian disruption.
Protein Processing, Post-Translational/physiology* ; Circadian Rhythm/physiology* ; Humans ; Animals ; CLOCK Proteins/physiology* ; Circadian Clocks/physiology* ; Phosphorylation ; Acetylation ; Ubiquitination ; Sumoylation

The seed kernel of Momordica cochinchinensis, i.e., Momordicae Semen, is used for medicinal purposes, but to date, no research has been reported on its chemical constituents. In this study, the chemical constituents of Momordicae Semen were investigated for the first time using silica gel column chromatography, semi-preparative HPLC, HR-MS, and NMR. As a result, eight compounds were isolated and identified as: p-hydroxybenzoic acid-7-O-trehaloside(mubeside A, 1), 2,6-dimethoxyphenol-O-β-D-apiosyl-(1→2)-β-D-glucoside(mubeside B, 2), 1-O-p-methoxybenzoyl-1,4-benzenediol-4-O-β-D-apiosyl-(1→2)-β-D-glucoside(mubeside C, 3), 1-O-p-hydroxybenzoyl-1,4-benzenediol-4-O-β-D-apiosyl-(1→2)-β-D-glucoside(mubeside D, 4), gypsogenin-3-O-β-D-galactosyl-(1→2)-β-D-glucuronoside(5), quillaic acid-3-O-β-D-galactosyl-(1→2)-β-D-glucuronoside(6), violanthin(7), and kaempferitrin(8). Compounds 1-4 are new compounds, while compounds 5-8 were isolated from Momordicae Semen for the first time.
Glycosides/isolation & purification* ; Drugs, Chinese Herbal/isolation & purification* ; Molecular Structure ; Magnetic Resonance Spectroscopy ; Chromatography, High Pressure Liquid

A mounting body of research suggests that circRNAs significantly contribute to the develop-ment of myocardial fibrosis.The microarray results of human circular RNA expression profile indicated that circHERC4_041 expression increased in the myocardium of patients with heart failure,RT-qPCR a-nalysis confirmed that the myocardial expression level of circHERC4_041 in individuals with heart failure were considerably elevated compared to that in healthy organ donors.Fluorescence in situ hybridization(FISH)confirmed that circHERC4_041 was abundant in the cytoplasm of human cardiomyocyte AC16.Overexpression of circHERC4_041 in mouse myocardial fibroblasts(mCFs)mediated by adenovirus in-hibited the expression of fibrosis-related proteins in mCFs.Experiments involving cell proliferation,wound healing,and Transwell assays demonstrated that overexpression of circHERC4_041 suppressed the growth and mobility of mCFs(P＜0.001).Sequence analysis results suggested that circHERC4_041 con-tains potential ribosome entry sequence(IRES)and open reading frame(ORF).Western blot confirmed that circHERC4_041 could translate the 516 amino acid HERC4-516aa protein,which was mainly located in the cytoplasm of the cell.Cell functional experiments confirmed that circHERC4_041 inhibited the fi-brotic phenotype of mCFs by specifically translating HERC4-516aa(P＜0.05).The specific interaction between HERC4-516aa and transglutaminase 2(TGM2)was confirmed by IP-MS screening and Co-IP i-dentification.Further results found that the degradation of TGM2 was promoted through proteasome path-way.The overexpression of TGM2 in mCFs facilitated by adenoviral vectors could counteract the suppres-sive effects of HERC4-516aa on the fibrotic phenotype of mCFs.Therefore,this study confirmed that the HERC4-516aa protein translated by circHERC4_041 can specifically bind to TGM2 to inhibit the fibrotic phenotype of myocardial fibroblasts.

Objective To evaluate the clinical value of 18F-fibroblast-activation protein inhibitor(18F-FAPI)PET/CT in malignant tumors exhibiting low uptake of 18F-fluorodeoxyglucose(18F-FDG).Methods We prospectively analyzed 62 patients with malignant tumors and low 18F-FDG uptake who underwent 18F-FAPI PET/CT in the Affiliated Cancer Hospital and Institute of Guangzhou Medical University from January 2021 to November 2022.Patient demographics information,clinical and radiological data were collected.Tumor lesions were categorized based on 18F-FAPI and 18F-FDG uptake relative to surrounding tissues into low-,moderate-,and high-uptake,with high uptake indicating positivity.The number and tracer uptake levels of primary tumors and metastatic lesions visualized by both 18F-FDG and 18F-FAPI were recorded and compared.Results Of the 62 primary tumors,18(29.0%)showed low-uptake and 44(71.0%)moderate-uptake on 18F-FDG PET,while 1(1.6%),6(9.7%),and 55(88.7%)showed low,moderate,and high uptake on 18F-FAPI,respectively.The maximum standardized uptake value(SUVmax)for primary tumors was significantly higher with 18F-FAPI than with 18F-FDG(7.5±5.6 vs.3.9±2.1,P<0.01).The number of positive lymph node foci revealed by 18F-FAPI was noticeably higher than that by 18F-FDG(77 vs.38,P<0.01).A total of 16 distant organ metastases were identified,with 11(68.8%)detected by 18F-FDG and 15(93.8%)by 18F-FAPI,showing no significant difference in detection rates(P>0.05).Conclusions 18F-FAPI PET/CT effectively visualizes primary and metastatic lesions in malignant tumors with low 18F-FDG uptake,suggesting its potential as a promising radiotracer for such malignancies.

Objective To compare the clinical outcomes of modified posterolateral approach and traditional posterolateral approach combined with open reduction and internal fixation via medial approach in treatment of trimalleolar fracture.Methods Sixty-two patients with trimalleolar fractures who underwent modified posterolateral approach combined with open reduction and internal fixation via medial approach from January 2019 to June 2022 in orthopedics department of our hospital were enrolled in the modified approach group,and 62 patients who underwent traditional posterolateral approach combined with open reduction and internal fixation via medial approach at the same period were matched as the traditional approach group.The perioperative indicators were collected.The range of ankle motion 12 months after surgery was measured.The Maryland score,American Orthopaedic Foot and Ankle Society(AOFAS)score and Baird-Jackson score were employed to evaluate the recovery of patients 12 months after surgery,and the occurence of complications was recorded.Results There was no significant difference in the operation time,intraoperative blood loss,incision length,postoperative drainage volume or pain score between the two groups(P<0.05).The Maryland scores,AOFAS scores and Baird-Jackson scores 12 months after surgery of the two groups were higher than those before operation(P<0.05),while there was no significant difference between the two groups(P<0.05).The range of ankle motion in the modified approach group was better than that in the traditional approach group,and the incidence of nerve injury after surgery was lower than that in the traditional approach group,with statistically significant differences(P<0.05).Conclusions The modified posterolateral approach combined with open reduction and internal fixation via medial approach in treatment of trimalleolar fracture can achieve good early clinical outcome,effectively improve range of ankle motion,and reduce postoperative nerve injury.

This study investigated the potential pathogenicity and genetic characteristics of ST314 Salmonella Kentucky(S.Ken-tucky)isolates from a broiler slaughterhouse.Antimicrobial susceptibility testing and whole-genome sequencing(WGS)were used to determine antimicrobial resistance,virulence factors,and the presence of antimicrobial resistance genes(ARGs)and mobile genetic elements(MGEs)among the isolates.The three multidrug resistant(MDR)isolates exhibited high resistance to multiple antimicrobial agents.The F4-2S strain exhibited resistance to 14 drugs across seven categories,whereas the F4T strain showed resistance to 13 drugs in the same number of categories.In contrast,the Y23 strain was resistant to nine drugs in six categories.Notably,F4-2S dem-onstrated high homology with F4T:both possessed 13 ARGs distributed across nine categories,in addition to a wide range of virulence factors,including secretion systems and effector proteins.The presence of IncR and IncX1 plasmids significantly enhanced both the antimicrobial resistance and pathogenicity of the isolates.The genome map of Y23 revealed a chromosome alongside two plasmids.The chromosome containedonly one resistance gene but several virulence factors,including the type III secretion system(T3SS),which is crucial for bacterial invasion.The plasmid pY23-1 contained eight types of 19 ARGs.Comparative analysis indicated that pY23-1 ex-hibited high homology with pZ1323SSL0055 and pSAL-045,all of which contained multiple ARGs,thus suggesting critical roles of these genes in the evolution of bacterial resistance.In conclusion,ST314 S.Kentucky demonstrated a complex mechanism of resis-tance coupled with significant pathogenic potential.The ARGs and MGEs in the plasmid contributed to the emergence and dissemina-tion of antimicrobial resistance.The multiple virulence factors present in the chromosome may be key factors driving the increasing virulence of ST314 S.Kentucky.

AIM:To observe the effect of continuous light on the structure and differential metabolites of gut microbiota in mice.METHODS:The mice were randomly divided into normal light(light/dark,LD)group and 24-hour continuous light(light/light,LL)group.The body weight,fasting blood glucose,serum free fatty acids,serum triacylglycerol and serum total cholesterol levels of each group of mice were measured after 10 weeks.Fresh feces were collected,and 16S rRNA sequencing technology was used to study the effect of continuous light on the diversity,structure,and species composition of gut microbiota in mice.Additionally,liquid chromatography-mass spectrometry(LC-MS)analysis was per-formed to observe the effect of continuous light on the metabolites in mice.RESULTS:Compared with the LD group,the body weight,fasting blood glucose and lipid levels of the LL group were increased(P＜0.05).At the phylum level,the proportion of Firmicutes in the LL group increased,while the proportion of Bacteroidetes decreased.At the class level,the abundance of norank_f_Muribaculaceae and Prevotellaceae_UCG-001 in the LL group decreased significantly,while the abundance of Lactobacillus,Turicibacter and Odoribacter increased significantly.Non-targeted metabolomics analysis iden-tified 65 and 73 differential metabolites under positive and negative modes,involving six major metabolic pathways,in-cluding ABC transporters,purine metabolism,pyrimidine metabolism,secondary bile acid biosynthesis,protein digestion and absorption,and choline metabolism in cancer.CONCLUSION:The structure and metabolites of gut microbiota in mice exposed to continuous light are relatively specific,and inosine may be a key biomarker and potential therapeutic tar-get for biological clock disorders.

Objective To compare the clinical outcomes of modified posterolateral approach and traditional posterolateral approach combined with open reduction and internal fixation via medial approach in treatment of trimalleolar fracture.Methods Sixty-two patients with trimalleolar fractures who underwent modified posterolateral approach combined with open reduction and internal fixation via medial approach from January 2019 to June 2022 in orthopedics department of our hospital were enrolled in the modified approach group,and 62 patients who underwent traditional posterolateral approach combined with open reduction and internal fixation via medial approach at the same period were matched as the traditional approach group.The perioperative indicators were collected.The range of ankle motion 12 months after surgery was measured.The Maryland score,American Orthopaedic Foot and Ankle Society(AOFAS)score and Baird-Jackson score were employed to evaluate the recovery of patients 12 months after surgery,and the occurence of complications was recorded.Results There was no significant difference in the operation time,intraoperative blood loss,incision length,postoperative drainage volume or pain score between the two groups(P<0.05).The Maryland scores,AOFAS scores and Baird-Jackson scores 12 months after surgery of the two groups were higher than those before operation(P<0.05),while there was no significant difference between the two groups(P<0.05).The range of ankle motion in the modified approach group was better than that in the traditional approach group,and the incidence of nerve injury after surgery was lower than that in the traditional approach group,with statistically significant differences(P<0.05).Conclusions The modified posterolateral approach combined with open reduction and internal fixation via medial approach in treatment of trimalleolar fracture can achieve good early clinical outcome,effectively improve range of ankle motion,and reduce postoperative nerve injury.

A mounting body of research suggests that circRNAs significantly contribute to the develop-ment of myocardial fibrosis.The microarray results of human circular RNA expression profile indicated that circHERC4_041 expression increased in the myocardium of patients with heart failure,RT-qPCR a-nalysis confirmed that the myocardial expression level of circHERC4_041 in individuals with heart failure were considerably elevated compared to that in healthy organ donors.Fluorescence in situ hybridization(FISH)confirmed that circHERC4_041 was abundant in the cytoplasm of human cardiomyocyte AC16.Overexpression of circHERC4_041 in mouse myocardial fibroblasts(mCFs)mediated by adenovirus in-hibited the expression of fibrosis-related proteins in mCFs.Experiments involving cell proliferation,wound healing,and Transwell assays demonstrated that overexpression of circHERC4_041 suppressed the growth and mobility of mCFs(P＜0.001).Sequence analysis results suggested that circHERC4_041 con-tains potential ribosome entry sequence(IRES)and open reading frame(ORF).Western blot confirmed that circHERC4_041 could translate the 516 amino acid HERC4-516aa protein,which was mainly located in the cytoplasm of the cell.Cell functional experiments confirmed that circHERC4_041 inhibited the fi-brotic phenotype of mCFs by specifically translating HERC4-516aa(P＜0.05).The specific interaction between HERC4-516aa and transglutaminase 2(TGM2)was confirmed by IP-MS screening and Co-IP i-dentification.Further results found that the degradation of TGM2 was promoted through proteasome path-way.The overexpression of TGM2 in mCFs facilitated by adenoviral vectors could counteract the suppres-sive effects of HERC4-516aa on the fibrotic phenotype of mCFs.Therefore,this study confirmed that the HERC4-516aa protein translated by circHERC4_041 can specifically bind to TGM2 to inhibit the fibrotic phenotype of myocardial fibroblasts.

This study investigated the potential pathogenicity and genetic characteristics of ST314 Salmonella Kentucky(S.Ken-tucky)isolates from a broiler slaughterhouse.Antimicrobial susceptibility testing and whole-genome sequencing(WGS)were used to determine antimicrobial resistance,virulence factors,and the presence of antimicrobial resistance genes(ARGs)and mobile genetic elements(MGEs)among the isolates.The three multidrug resistant(MDR)isolates exhibited high resistance to multiple antimicrobial agents.The F4-2S strain exhibited resistance to 14 drugs across seven categories,whereas the F4T strain showed resistance to 13 drugs in the same number of categories.In contrast,the Y23 strain was resistant to nine drugs in six categories.Notably,F4-2S dem-onstrated high homology with F4T:both possessed 13 ARGs distributed across nine categories,in addition to a wide range of virulence factors,including secretion systems and effector proteins.The presence of IncR and IncX1 plasmids significantly enhanced both the antimicrobial resistance and pathogenicity of the isolates.The genome map of Y23 revealed a chromosome alongside two plasmids.The chromosome containedonly one resistance gene but several virulence factors,including the type III secretion system(T3SS),which is crucial for bacterial invasion.The plasmid pY23-1 contained eight types of 19 ARGs.Comparative analysis indicated that pY23-1 ex-hibited high homology with pZ1323SSL0055 and pSAL-045,all of which contained multiple ARGs,thus suggesting critical roles of these genes in the evolution of bacterial resistance.In conclusion,ST314 S.Kentucky demonstrated a complex mechanism of resis-tance coupled with significant pathogenic potential.The ARGs and MGEs in the plasmid contributed to the emergence and dissemina-tion of antimicrobial resistance.The multiple virulence factors present in the chromosome may be key factors driving the increasing virulence of ST314 S.Kentucky.