Targeted covalent inhibitors,primarily targeting cysteine residues,have attracted great attention as potential drug candidates due to good potency and prolonged duration of action.However,their dis-covery is challenging.In this research,a database-assisted liquid chromatography-tandem mass spec-trometry(LC-MS/MS)strategy was developed to quickly discover potential cysteine-targeting compounds.First,compounds with potential reactive groups were selected and incubated with N-acetyl-cysteine in microsomes.And the precursor ions of possible cysteine-adducts were predicted based on covalent binding mechanisms to establish in-house database.Second,substrate-independent product ions produced from N-acetyl-cysteine moiety were selected.Third,multiple reaction monitoring scan was conducted to achieve sensitive screening for cysteine-targeting compounds.This strategy showed broad applicability,and covalent compounds with diverse structures were screened out,offering structural resources for covalent inhibitors development.Moreover,the screened compounds,norket-amine and hydroxynorketamine,could modify synaptic transmission-related proteins in vivo,indicating their potential as covalent inhibitors.This experimental-based screening strategy provides a quick and reliable guidance for the design and discovery of covalent inhibitors.

Targeted covalent inhibitors, primarily targeting cysteine residues, have attracted great attention as potential drug candidates due to good potency and prolonged duration of action. However, their discovery is challenging. In this research, a database-assisted liquid chromatography-tandem mass spectrometry (LC-MS/MS) strategy was developed to quickly discover potential cysteine-targeting compounds. First, compounds with potential reactive groups were selected and incubated with N-acetyl-cysteine in microsomes. And the precursor ions of possible cysteine-adducts were predicted based on covalent binding mechanisms to establish in-house database. Second, substrate-independent product ions produced from N-acetyl-cysteine moiety were selected. Third, multiple reaction monitoring scan was conducted to achieve sensitive screening for cysteine-targeting compounds. This strategy showed broad applicability, and covalent compounds with diverse structures were screened out, offering structural resources for covalent inhibitors development. Moreover, the screened compounds, norketamine and hydroxynorketamine, could modify synaptic transmission-related proteins in vivo, indicating their potential as covalent inhibitors. This experimental-based screening strategy provides a quick and reliable guidance for the design and discovery of covalent inhibitors.

Objective To investigate and analyze the occupational stress levels and influencing factors among radiation workers in China, and provide a reference for alleviating occupational stress and promoting mental health. Methods Using the general situation questionnaire, Effort-Reward Imbalance questionnaire, and radiation protection knowledge questionnaire, a convenience sampling method was adopted to investigate the occupational stress of 243 radiation workers in Liaoning, Fujian, Guangdong, and Xinjiang provinces. The independent samples t-test, one-way analysis of variance, chi-square test, and binary logistic regression were used to analyze the influencing factors. Results The average score of Effort-Reward Imbalance was 0.97 ± 0.22, and 100 (41.15%) radiation workers had occupational stress. There were significant differences in the detection rate of occupational stress among radiation workers of different ages, working years in radiation positions, monthly incomes, daily sleep durations, and daily working hours (P < 0.05). Logistic regression analysis identified daily working hours as a factor contributing to occupational stress. Conclusion The occupational stress among radiation workers in China is relatively severe. It is recommended to pay attention to the associated risks and implement targeted intervention measures to reduce the impact of occupational stress.

Objective:To investigate the association between serum 25-hydroxyvitamin D [25(OH)D] levels and 24-h urinary calcium excretion (24-h UCaE) and hypercalciuria in Chinese adults.Methods:This cross-sectional study was conducted from March 2022 to March 2023 in nine cities in China and included 1 239 residents. Demographic characteristics were collected through questionnaires and physical examinations, fasting blood samples were assessed for bone metabolism indicators, and 24-h urine samples were used to determine the 24-h UCaE. Multiple linear regression analysis was used to explore the relationship between serum 25(OH)D and 24-h UCaE and bone metabolism indexes. The relationship between serum 25(OH)D and hypercalciuria was analyzed using a multiple logistic regression model combined with restricted cubic spline modeling.Results:The mean participant age was (47.9±18.1) years, of which 453 (36.6%) were male. The percentages of vitamin D sufficiency, insufficiency, and deficiency were 7.6% (94/1 239), 29.0% (359/1 239), and 63.4% (786/1 239), respectively. The multiple linear regression model showed that after adjusting for the covariates the 24-h UCaE gradually increased with higher levels of 25(OH)D ( P overall <0.001, P nonlinear <0.001). The logistic regression analysis revealed that compared with the vitamin D deficient group, the OR for the prevalence of hypercalciuria in the vitamin D sufficient and vitamin D insufficient groups were 3.290 (95% CI 1.745 to 6.202) and 3.742 (95% CI 2.458 to 5.697), respectively. The results of the restricted cubic spline modeling showed a positive nonlinear relationship between 25(OH)D and the prevalence of hypercalciuria ( P overall <0.001, P nonlinear <0.001). The prevalence of hypercalciuria increased when 25(OH)D was >17.00 μg/L and peaked at 26.71 μg/L, after which there was a decreasing trend in the prevalence of hypercalciuria with increasing 25(OH)D. Conclusion:Associations between serum 25(OH)D levels and urinary calcium excretion and the prevalence of hypercalciuria were observed in the Chinese adult population.

Objective:To investigate the association between serum 25-hydroxyvitamin D [25(OH)D] levels and 24-h urinary calcium excretion (24-h UCaE) and hypercalciuria in Chinese adults.Methods:This cross-sectional study was conducted from March 2022 to March 2023 in nine cities in China and included 1 239 residents. Demographic characteristics were collected through questionnaires and physical examinations, fasting blood samples were assessed for bone metabolism indicators, and 24-h urine samples were used to determine the 24-h UCaE. Multiple linear regression analysis was used to explore the relationship between serum 25(OH)D and 24-h UCaE and bone metabolism indexes. The relationship between serum 25(OH)D and hypercalciuria was analyzed using a multiple logistic regression model combined with restricted cubic spline modeling.Results:The mean participant age was (47.9±18.1) years, of which 453 (36.6%) were male. The percentages of vitamin D sufficiency, insufficiency, and deficiency were 7.6% (94/1 239), 29.0% (359/1 239), and 63.4% (786/1 239), respectively. The multiple linear regression model showed that after adjusting for the covariates the 24-h UCaE gradually increased with higher levels of 25(OH)D ( P overall <0.001, P nonlinear <0.001). The logistic regression analysis revealed that compared with the vitamin D deficient group, the OR for the prevalence of hypercalciuria in the vitamin D sufficient and vitamin D insufficient groups were 3.290 (95% CI 1.745 to 6.202) and 3.742 (95% CI 2.458 to 5.697), respectively. The results of the restricted cubic spline modeling showed a positive nonlinear relationship between 25(OH)D and the prevalence of hypercalciuria ( P overall <0.001, P nonlinear <0.001). The prevalence of hypercalciuria increased when 25(OH)D was >17.00 μg/L and peaked at 26.71 μg/L, after which there was a decreasing trend in the prevalence of hypercalciuria with increasing 25(OH)D. Conclusion:Associations between serum 25(OH)D levels and urinary calcium excretion and the prevalence of hypercalciuria were observed in the Chinese adult population.

Objective To isolate a Acinetobacter baumannii(Ab)phage from underground sewage,study its prop-erties,and to provide a theoretical basis for phage treatment of Ab infection.Methods Double-layer agar tech-nique was used to isolate phages by using Ab GY-6 as the host strain.Biological characterization and therapeutic effect of the phage was tested.Genetic information of the phage was analyzed.Results Ab phage Abgy202162 was isolated.Transmission electron microscopy(TEM)analysis showed that the morphology of Abgy202162 exhibited an icosahedral structure.Biological characteristic analysis showed that the optimal multiplicity of infection was 1,the latent period was 5 min,and the burst size was approximately 520 PFU per cell.In addition,Abgy202162 re-mained stable at different concentrations of chloroform,pH,and temperatures.Sodium dodecyl sulfate-polyacryl-amide gel electrophoresis(SDS-PAGE)analysis showed that it contained 10 proteins with molecular weights ran-ging from 15 to 100 ku.The double-stranded(ds)DNA genome of Abgy202162 consisted of 40 889 bp and its G+C content was 38.85％.It contained 47 open reading frames(ORFs),of which 26 had specific functions,but no virulence related genes or antibiotic resistance genes were found.Phylogenetic analysis showed that Abgy202162 was a new phage in the Autographiviridae family,Beijerinkvirinae subfamily,and Friunavirus genus.Abgy202162 showed the ability to prevent Ab infection in the Galleria mellonella in vivo model.Conclusion The phage Ab-gy202162 has strong environmental tolerance and high safety,indicating its potential as an antibiotic alternative used in the treatment of infections caused by Ab.

【Objective】 To investigate the anemia status of infants and toddlers aged 6 - 24 months in Linxia Hui Autonomous Prefecture, Gansu Province, and to comprehensively evaluate the differences in feeding behaviors between anaemic and normal children through the infant and child feeding index (ICFI) and feeding knowledge scores, so as to provide reference for the guidance of infants and young children feeding in ethnic minority areas and the promotion of children′s growth and development. 【Methods】 Taking infants and young children aged 6 - 24 months in Linxia Prefecture as the study subjects, a multi-stage random sampling method was used to select children who met the requirements from 5 townships and 5 villages in 7 counties in 2019 and 2020.Periphral blood samples were collected to test the level of hemoglobin, so as to determine the anemia status.Meanwhile, physical examination was performed and a questionnaire survey of guardians was conducted to analyze the association betweenanaemia and feeding patterns 【Results】 A total of 3 901 infants and children were included in this study, of whom 729 (18.70%) were anaemic, with a mean ICFI score of 12.56±2.70 and a mean feeding knowledge score of 1.97±1.01.There was no statistically significant association of low feeding knowledge score and low ICFI with anaemia after adjusting for confounders (P>0.05), Unqualified meat addition in ICFI was a risk factor for anaemia (OR=1.355, P=0.042), while non-bottle feeding in the past 24 hours (OR=0.762, P=0.021), and breastfeeding in the past 24 hours of infants and toddlers aged 12 - 24 months (OR=0.228, P=0.018) were protective factor for anemia in infants and toddlers aged 12 - 24 months. 【Conclusions】 The average prevalence of anemia in infants and toddlers aged 6 - 24 months in Linxia Hui Autonomous Prefecture of Gansu Province is high, but the level of infant feeding and the level of feeding knowledge of caregivers are low.Early adherence to breastfeeding, timely addition of supplementary food, and more comsumpution of meat for children are conducive to preventing anemia.

Objective To analyze the differences in serum amino acid levels between preeclampsia(PE)and normal pregnant women in Urumqi,and to explore the correlation between amino acids with statistically significant differences and PE severity,as well as their diagnostic value for PE patients.Methods A total of 49 normal pregnant women who visited Urumqi Maternal and Child Health Hospital from June 2021 to June 2023 were selected as the control group and 55 PE pregnant women were selected as the PE group,and the PE group was further divided into mild PE group(25 cases)and severe PE group(30 cases).Liquid chromatogra-phy-tandem mass spectrometry technology was used to determine the levels of 25 metabolites in pregnant women's serum.Spearman correlation analysis was used to analyze the correlation between the amino acid lev-els and PE severity.Logistic regression was used to correct for potential confounding factors,and receiver op-erating characteristic curve was used to analyze the diagnostic efficacy of amino acids with significant differ-ences in PE.Results There were statistically significant differences in the body mass index(BMI)and deliv-ery method between the PE group and the control group(P＜0.05).The serum levels of histidine,threonine,glutamine,ethanolamine,methylhistidine,and canine uric acid in the PE group were higher than those in the control group(P＜0.05).The serum levels of threonine,glutamine,methylhistidine,and canine uric acid in the severe PE group were higher than those in the mild PE group and control group(P＜0.05).The serum ethanolamine levels in the mild group and severe PE group were higher than those in the control group(P＜0.05).The serum histidine levels in the severe PE group were higher than those in the control group(P＜0.05).Correlation analysis showed that serum glutamine,ethanolamine,methylhistidine,and canine uric acid were positively correlated with the severity of PE(P＜0.05).After adjusting for BMI,there were still statisti-cally significant differences in the levels of threonine,glutamine,and methylhistidine between the PE group and the control group(P＜0.05).The area under the curve of the combined detection of serum threonine,glu-tamine,and methylhistidine for diagnosing PE was 0.734.Conclusion There is a certain correlation between serum levels of threonine,glutamine,and methylhistidine and the severity of PE,and the combined detection has high diagnostic value for patients with PE.

Flagella are the main motility structure of Clostridioides difficile that affects the adhesion, colonization, and virulence of C. difficile in the human gastrointestinal tract. The FliL protein is a single transmembrane protein bound to the flagellar matrix. This study aimed to investigate the effect of the FliL encoding gene flagellar basal body-associated FliL family protein (fliL) on the phenotype of C. difficile. The fliL gene deletion mutant (ΔfliL) and its corresponding complementary strains (: : fliL) were constructed using allele-coupled exchange (ACE) and the standard molecular clone method. The differences in physiological properties such as growth profile, antibiotic sensitivity, pH resistance, motility, and spore production ability between the mutant and wild-type strains (CD630) were investigated. The ΔfliL mutant and the : : fliL complementary strain were successfully constructed. After comparing the phenotypes of strains CD630, ΔfliL, and : : fliL, the results showed that the growth rate and maximum biomass of ΔfliL mutant decreased than that of CD630. The ΔfliL mutant showed increased sensitivity to amoxicillin, ampicillin, and norfloxacin. Its sensitivity to kanamycin and tetracycline antibiotics decreased, and the antibiotic sensitivity partially returned to the level of CD630 strain in the : : fliL strain. Moreover, the motility was significantly reduced in the ΔfliL mutant. Interestingly, the motility of the : : fliL strain significantly increased even when compared to that of the CD630 strain. Furthermore, the pH tolerance of the ΔfliL mutant significantly increased or decreased at pH 5 or 9, respectively. Finally, the sporulation ability of ΔfliL mutant reduced considerably compared to the CD630 strain and recovered in the : : fliL strain. We conclude that the deletion of the fliL gene significantly reduced the swimming motility of C. difficile, suggesting that the fliL gene is essential for the motility of C. difficile. The fliL gene deletion significantly reduced spore production, cell growth rate, tolerance to different antibiotics, acidity, and alkalinity environments of C. difficile. These physiological characteristics are closely related to the survival advantage in the host intestine, which is correlated with its pathogenicity. Thus, we suggested that the function of the fliL gene is closely related to its motility, colonization, environmental tolerance, and spore production ability, which consequently affects the pathogenicity of C. difficile.
Humans ; Clostridioides/metabolism* ; Clostridioides difficile/metabolism* ; Bacterial Proteins/metabolism* ; Virulence ; Anti-Bacterial Agents/metabolism*

Objective : To explore the role of Argonaute ( Ago) gene and RNA⁃Dependent RNA Polymerase (RDRP) gene of Aspergillus flavus in the growth and development about the RNAi mechanism . Methods : A. flavus Ago1 , Ago2 , RDRP1 , RDRP3 gene mutant strains were constructed by homologous recombination . The growth and development of the mutant strains were observed on potato dextrose agar(PDA) + uracil uridine (UU) medium inoculated with 3 μl 106 CFU/mL spores . 200 , 400 μg cell wall pressure agent conidored ( CR) , 0. 8 mol/L , 1 . 6 mol/L osmotic pressure agent NaCl , 2 mmol/L , 4 mmol/L oxidative pressure agent hydrogen peroxide (H2 O2 ) and 0. 01% , 0. 02% genomic damage agent methyl mesylate (MMS) were added to the Yeast extract Glucose Minimum (YGM) + UU medium to analyze the stress response of the mutant strains . Results : A. flavus mutant strains about ΔAgo1 , ΔAgo2 , ΔRDRP1 , ΔRDRP3 were successfully constructed and its growth and development were normal . The ΔAgo1 and ΔAgo2 strains reduced the stress effects on cell wall and osmotic pressure compared to the control . Ago1 gene deletion reduced the effect of H2 O2 , and conversely RDRP3 gene deletion increased the inhibition of H2 O2 . The Ago2 and RDRP1 strains reduced the effect on genetic damage agent . In addition , ΔRDRP1 increased the effect of osmotic stress . Conclusion The Ago1 , Ago2 , RDRP1 and RDRP3 genes of A. flavus are not in⁃ volved in the regulation of growth rate and asexual reproduction and can participate in the regulating of the host stress response to the environment .