A prokaryotic expression vector for the mutant diphtheria toxin CRM197 was constructed and expressed in Esch-erichia coli cells.Anti-CRM197 antibody concentrations were detected in serum samples of healthy volunteers.The crm 197 gene was codon-optimized in E.coli and cloned into the plasmid pET28a(+)under optimized expression conditions.CRM197 was purified using Ni-NTA spin columns and ion exchange chromatography,and confirmed by western blot analysis.The puri-fied CRM197 was used to detect specific anti-CRM197 antibody levels in serum samples of different age groups.The results showed that soluble codon-optimized CRM197 was successfully expressed under optimized expression conditions.The purity of CRM197 was more than 95％,as determined with Ni-NTA spin columns and ion exchange chromatography,consistent with the single specific bands obtained by western blot analysis and detection of serum levels of the anti-CRM197 antibody.Collec-tively,these results confirmed that the proposed expression strategy achieved high-yield production of soluble CRM197,al-though high levels in human serum may affect evaluation of immune interactions with glycan-CRM197 conjugates for applica-tion as a diagnostic antigen.The diphtheria mutant toxin CRM197 is used in many conjugate vaccines.The synthetic crm 197 gene with codon optimization in pET28a was transformed into E.coli Origami B(DE3)cells.CRM197 was induced by isopro-pyl β-d-1-thiogalactopyranoside and high level accumulation of soluble CRM197 was purified using Ni-NTA spin columns and ion exchange chromatography.The purity of the final prepara-tion reached 95％.CRM197 was used to detect the concentra-tions of the anti-CRM197 antibody in serum samples of healthy volunteers of different ages.The proposed expression strategy yielded high production of CRM197,which could interfere with evaluations of induced immune interactions by glycan-CRM197 conjugates and prohibit application as a diagnostic antigen.

Human-animal parasitic diseases caused by medical helminths are hazardous to human health. Genetic polymorphism studies on medical helminth populations can not only understand the biological characteristics and genetic structure of their populations, but also help reveal how they adapt to their parasitic environment, thus contributing to deepen our understanding of the epidemiological patterns of parasitic diseases and improve our understanding of accurate prevention and control of parasitic diseases. With the development of molecular biology, molecular markers such as DNA barcodes, simple sequence repeats, and single nucleotide polymorphism markers have been widely used to study the genetic relationships among parasite populations and individuals, and to reveal the genetic variation of parasite populations and the evolution of species origins. In this paper, we systematically review the application of three molecular markers commonly used in the study of genetic polymorphism in medical helminths, with a view to laying the foundation for related research.

OBJECTIVE: Campylobacter jejuni NCTC11168 is commonly used as a standard strain for flagellar biosynthesis research. In this report, two distinguished phenotypic isolates (CJ1Z, flhA mutant strain, lawn; CJ2S, flhA complemented strain, normal colony) appeared during laboratory passages for NCTC11168. METHODS: Phenotypic assessments, including motility plates, transmission electron microscopy, biofilm formation assay, autoagglutination assay, and genome re-sequencing for these two isolates (CJ1Z, flhA mutant strain; CJ2S, flhA complemented strain) were carried out in this study. RESULTS: Transmission electron microscopy revealed that the flagellum was lost in CJ1Z. Phenotypic assessments and genome sequencing of the two isolates were performed in this study. The capacity for biofilm formation, colony auto-agglutination, and isolate motility was reduced in the mutant CJ1Z. Comparative genomic analysis indicated a unique native nucleotide insertion in flhA (nt, 2154) that caused the I719Y and I720Y mutations and early truncation in flhA. CONCLUSION FlhA has been found to influence the expression of flagella in C. jejuni. To the best of our knowledge, this is the first study to describe the function of the C-terminal of this protein.
Campylobacter jejuni/genetics* ; Bacterial Proteins/metabolism* ; Mutation ; Biological Variation, Population

Objective: To investigate the level of psychosocial factors in workplace and their health effects among workers in a natural gas field. Methods: A prospective and open cohort of natural gas field workers was established to study the level of workplace psychosocial factors and their health effects, with a follow-up every 5 years. In October 2018, a cluster sampling method was used to conduct a baseline survey of 1737 workers in a natural gas field, including a questionnaire survey on demographic characteristics, workplace psychosocial factors and mental health outcomes, physiological indicators such as height and weight, and biochemical indicators such as blood routine, urine routine, liver function and kidney function. The baseline data of the workers were statistically described and analyzed. The psychosocial factors and mental health outcomes were divided into high and low groups according to the mean score, and the physiological and biochemical indicators were divided into normal and abnormal groups according to the reference range of normal values. Results: The age of 1737 natural gas field workers was (41.8±8.0) years old, and the length of service was (21.0±9.7) years. There were 1470 male workers (84.6%). There were 773 (44.5%) high school (technical secondary school) and 827 (47.6%) college (junior college) graduates, 1490 (85.8%) married (including remarriage after divorce), 641 (36.9%) smokers and 835 (48.1%) drinkers. Among the psychosocial factors, the detection rates of high levels of resilience, self-efficacy, colleague support and positive emotion were all higher than 50%. Among the mental health outcomes evaluation indexes, the detection rates of high levels of sleep disorder, job satisfaction and daily stress were 41.82% (716/1712), 57.25% (960/1677) and 45.87% (794/1731), respectively. The detection rate of depressive symptoms was 22.77% (383/1682). The abnormal rates of body mass index (BMI), triglyceride and low density lipoprotein were 46.74% (810/1733), 36.50% (634/1737) and 27.98% (486/1737), respectively. The abnormal rates of systolic blood pressure, diastolic blood pressure, uric acid, total cholesterol and blood glucose were 21.64% (375/1733), 21.41% (371/1733), 20.67% (359/1737), 20.55% (357/1737) and 19.17% (333/1737), respectively. The prevalence rates of hypertension and diabetes were 11.23% (195/1737) and 3.45% (60/1737), respectively. Conclusion: The detection rates of high level psychosocial factors in natural gas field workers are high, and their effects on physical and mental health remain to be verified. The establishment of a cohort study of the levels and health effects of psychosocial factors provides an important resource for confirming the causal relationship between workplace psychosocial factors and health.
Humans ; Male ; Adult ; Middle Aged ; Natural Gas ; Cohort Studies ; Prospective Studies ; Oil and Gas Fields ; Workplace/psychology* ; Surveys and Questionnaires

Objective: To analyze the course of disease and epidemiological parameters of COVID-19 and provide evidence for making prevention and control strategies. Methods: To display the distribution of course of disease of the infectors who had close contacts with COVID-19 cases from January 1 to March 15, 2020 in Guangdong Provincial, the models of Lognormal, Weibull and gamma distribution were applied. A descriptive analysis was conducted on the basic characteristics and epidemiological parameters of course of disease. Results: In total, 515 of 11 580 close contacts were infected, with an attack rate about 4.4%, including 449 confirmed cases and 66 asymptomatic cases. Lognormal distribution was fitting best for latent period, incubation period, pre-symptomatic infection period of confirmed cases and infection period of asymptomatic cases; Gamma distribution was fitting best for infectious period and clinical symptom period of confirmed cases; Weibull distribution was fitting best for latent period of asymptomatic cases. The latent period, incubation period, pre-symptomatic infection period, infectious period and clinical symptoms period of confirmed cases were 4.50 (95%CI:3.86-5.13) days, 5.12 (95%CI:4.63-5.62) days, 0.87 (95%CI:0.67-1.07) days, 11.89 (95%CI:9.81-13.98) days and 22.00 (95%CI:21.24-22.77) days, respectively. The latent period and infectious period of asymptomatic cases were 8.88 (95%CI:6.89-10.86) days and 6.18 (95%CI:1.89-10.47) days, respectively. Conclusion: The estimated course of COVID-19 and related epidemiological parameters are similar to the existing data.
COVID-19 ; Cohort Studies ; Contact Tracing ; Humans ; Incidence ; Prospective Studies

Objective: To expore the correlation between neck disability, neck pain and muscle strength in cervical pondylosis of office worker, and to provide scientific basis for the prevention and treatment of cervical spondylosis. Methods: In April 2021 ,234 patients with cervical spondylotic myelopathy treated in the Subsidiary Rehabilitation Hospital of Fujian University of Traditional Chinese Medicine from April 2015 to April 2017 were selected, the correlation between Neck Disability Index (NDI) score, neck pain and muscle strength was analyzed using the Spearman rank correlation method. Mann-Whitney U test was used to compare the difference of maximum muscle strength of isometric contraction. Results: NDI score was negatively correlated with neck flexion, extension, and muscle strength in the left and right flexion directions (r(s)=-0.164, -0.169, -0.222, -0.176, P=0.012, 0.010, 0.001 , 0.007). In mild and moderate functional disorder patients, the muscle strength in flexion, extension and left and right flexion direction was greater, the difference was statistically significant (P <0.01). Conclusion: There is a negative correlation between cervical functional disorder and cervical muscle strength in office workers, suggesting that strengthening cervical muscle strength may be a way to improve cervical spine function.
Cervical Vertebrae ; Humans ; Muscle Strength/physiology* ; Neck Muscles/physiology* ; Neck Pain/physiopathology* ; Occupational Diseases/physiopathology* ; Range of Motion, Articular/physiology* ; Spondylosis/physiopathology*

To explore the effects of psychological capital social support and their interaction on job satisfaction in Methods natural gas field workers. A total of 1 473 workers from a natural gas field were selected as the research subjects ， using convenient sampling method. Job Satisfaction Questionnaire Psychological Capital Questionnaire and Social Support ， Results Scale were used to investigate the scores of job satisfaction psychological capital and social support level. The ， ， detection rates of job satisfaction psychological capital and social support in the high level group were 55.9% 52.5% and ， 48.1% respectively. The detection rates of job satisfaction of workers in the high level psychological capital group and high level （ social support group were higher than those in the low level psychological capital group and low level social support group 67.4% vs ， vs ， P ） 43.3% 71.9% 41.2% all <0.01 . The results of multivariate logistic regression analysis showed that psychological capital ［ （CI） （ - ） and social support had positive effects on job satisfaction odds ratio and 95% confidence interval were 1.58 1.17 2.41 （ - ）， ， P ］ ， and 2.53 1.82 3.52 respectively all <0.01 . Moreover the psychological capital and social support had additive effect on ［ CI （ - ）， CI job satisfaction relative excess risk of interaction and 95% was 3.07 1.02 5.12 attributable proportion and 95% was （ - ）， CI （ - ）］， 0.48 0.35 0.61 synergy index and 95% was 2.34 1.72 3.16 but there was no multiplication interaction between （P ）Conclusion psychological capital and social support >0.05 . Psychological capital and social support can positively affect job satisfaction of natural gas workers. There is an additive interaction between psychological capital and social support on job ， satisfaction but no multiplicative interaction is found. Keywords: ； ； ； ； ； Psychological capital Social support Job satisfaction Interaction Natural gas Worker

Objective To determine the distribution of two important virulence factors [lipooligosaccharide (LOS) and capsular polysaccharide (CPS)] in Campylobacter jejuni (C. jejuni) isolated from different sources in China and to develop a rapid screening method for Guillain–Barré syndrome (GBS)-associated strains. Methods Whole-genome sequencing was carried out for 494 C. jejuni strains. The OrthoMCL software was used to define the LOS/CPS gene clusters. CPS genotyping was performed with serotype-specific sequence alignment using the BLAST software. Real-time Polymerase chain reaction (PCR) was developed with the unique sequences of specific CPS types. Results Nine novel and 29 previously confirmed LOS classes were identified. LOS classes A, B, and C were the most common (48.2％, 238/494) among the 494 strains. Twenty-six capsular types were identified in 448 strains. HS2, HS4c, HS5/31, HS19, and HS8/17 were the most frequent CPS genotypes (58.7％, 263/448). Strains of 17 CPS genotypes (strain number > 5) had one or two prevalent LOS classes (P < 0.05). Multiplex real-time PCR for rapid identification of HS2, HS19, and HS41 was developed and validated with strains of known serotypes. Conclusion Our results describe the genetic characteristics of the important virulence factors in C. jejuni strains in China. The multiplex real-time PCR developed in this study will facilitate enhanced surveillance of GBS-associated strains in China.

Aim To explore the effeet of riboflavin on the establishment of pressure overload-induced heart failure model in mice by thoracic aortie constrietion (TAC ) and its preventive mechanism.Methods Eight-week-old SPF C57BL/6J mice were seleeted and divided into four groups; Sham group.Sham + ribofla¬vin group, TAC group and TAC + riboflavin group.A mouse heart failure model was constructed in the TAC group.The miee in the TAC + riboflavin group were given riboflavin by gavage one week before and eight weeks after the operation.The cardiac ultrasound inde¬xes, the changes of cardiac morphology and mitochon¬drial function indexes, the expression of apoptosis pro¬teins, ATP content, SCAD mRNA and protein expres¬sion, enzyme activity and flavin adenine dinucleotide (FAD) content in myocardial tissues were detected.Hie free fatty acid content in serum and myocardial tis¬sues were also detected.Results Compared with the sham group, the cardiac function indexes of the mice in the TAC group decreased, anrl typical heart failure occurred.Moreover, the expression of SCAD, enzyme activity, ATP and FAD content in the myocardium sig-nificantly decreased, and the free fatty acid content in myocardium and serum significantly increased.Com¬pared with the TAC group, after riboflavin treatment, the cardiac function of mice in TAC + Riboflavin group was significantly improved.In addition, ATP content, SCAD expression, enzyme activity and FAD content in myocardium all significantly increased, and free fatty acid content in myocardium and serum markedly de¬creased.Conclusions Riboflavin may improve myo-cardial energy metabolism by increasing FAD content and activating SCAD, thereby inhibiting pressure over¬load-induced heart failure in mice.

Molecular pharmacognosy is a science of classification and identification, cultivation and protection, and production of active ingredients of graduated drugs at the molecular level. The proposal of molecular pharmacognosy allows the research of crude drugs to advance from the microscopic level to the genetic level. Pueraria lobata root, as a medicinal and edible plant, has high application value and economic value. There are many varieties that are easy to cause confusion, and it is not easy to distinguish and identify according to traditional identification methods. Moreover, the research of P. lobate root at the genetic level is still relatively shallow. the study received extensive attention of scholars. This article reviews recent research on molecular identification of P. lobate, transcriptome sequencing, cloning and synthesis of functional genes of P. lobate root in recent years in order to provide references for further promoting the development and utilization of P. lobate root and its active ingredients.
Pharmacognosy ; Plant Roots/genetics* ; Pueraria