To screen and identify a chitosanase with high stability, we cloned the chitosanase gene from Bacillus atrophaeus with a high protease yield from the barren saline-alkali soil and expressed this gene in Escherichia coli. The expressed chitosanase of B. atrophaeus (BA-CSN) was purified by nickel-affinity column chromatography. The properties including optimal temperature, optimal pH, substrate specificity, and kinetic parameters of BA-CSN were characterized. The results showed that BA-CSN had the molecular weight of 31.13 kDa, the optimal temperature of 55 ℃, the optimal pH 5.5, and good stability at temperatures below 45 ℃ and pH 4.0-9.0. BA-CSN also had good stability within 4 h of pH 3.0 and 10.0, be activated by K⁺, Na⁺, Mn²⁺, Ca²⁺, Mg²⁺, and Co²⁺, (especially by Mn²⁺), and be inhibited by Fe³⁺, Cu²⁺, and Ag⁺. BA-CSN showcased the highest relative activity in the hydrolysis of colloidal chitosan, and it had good hydrolysis ability for colloidal chitin. Under the optimal catalytic conditions, BA-CSN demonstrated the Michaelis constant K_m and maximum reaction rate V_max of 9.94 mg/mL and 26.624 μmoL/(mL·min), respectively, for colloidal chitosan. In short, BA-CSN has strong tolerance to acids and alkali, possessing broad industrial application prospects.
Bacillus/genetics* ; Hydrogen-Ion Concentration ; Escherichia coli/metabolism* ; Glycoside Hydrolases/biosynthesis* ; Substrate Specificity ; Enzyme Stability ; Chitosan/metabolism* ; Temperature ; Kinetics ; Cloning, Molecular ; Bacterial Proteins/biosynthesis* ; Recombinant Proteins/genetics*

OBJECTIVE To explore the effect of hydrogen peroxide disinfectant on terminal disinfection in wards of medical institutions.METHODS The surfaces of highly frequent contact objects of the wards of the First Affilia-ted Hospital of Nanchang University from which the public health center patients were discharged between Apr.2024 and Jun.2024 were respectively disinfected with 0.5％(low)and 5％(high)concentrations of hydrogen peroxide disinfecting wipes,totally 180 samples were randomly collected before and after the disinfection,and the pathogens were detected.The air of the wards from which the public health center patients were discharged be-tween Jul.2024 and Aug.2024 were disinfected with hydrogen peroxide dry mist disinfection device,and 90 sam-ples were respectively collected before and after the disinfection.Geobacillus stearothermophilus was used as the biological indicator and placed at various points within the air-disinfected wards to evaluate the disinfection level.The environmental sampling results and distribution of bacteria were observed and compared.RESULTS The qualified rates of disinfection of the object surfaces were 95.56％(86/90)and 98.89％(89/90)respectively for the low and high concentratioins of hydrogen peroxide disinfecting wipes,and there was no significant difference in the disinfection effect.Totally 120 strains of pathogens were isolated from unqualified samples before the disinfection,among which gram-negative bacteria(69.17％)were dominant,and the isolation rate of multidrug-resistant or-ganisms was 22.50％(27/120);only 1 strain of carbapenem-resistant Acinetobacter baumannii was isolated after the disinfection.The qualified rate of disinfection of air in the wards was 96.00％by 7.5％hydrogen peroxide dry mist disinfection device,the average bacterial colony counts in the air were 2 CFU/(5 min·vsl)after the dis-infection,and the killing rate of Geobacillus stearothermophilus was 100.00％by the air disinfection.CONCLUSION The hydrogen peroxide disinfectant can meet the requirement for terminal disinfection of the wards of the medical institutions,and it is portable and highly efficient.

OBJECTIVE To explore the effect of hydrogen peroxide disinfectant on terminal disinfection in wards of medical institutions.METHODS The surfaces of highly frequent contact objects of the wards of the First Affilia-ted Hospital of Nanchang University from which the public health center patients were discharged between Apr.2024 and Jun.2024 were respectively disinfected with 0.5％(low)and 5％(high)concentrations of hydrogen peroxide disinfecting wipes,totally 180 samples were randomly collected before and after the disinfection,and the pathogens were detected.The air of the wards from which the public health center patients were discharged be-tween Jul.2024 and Aug.2024 were disinfected with hydrogen peroxide dry mist disinfection device,and 90 sam-ples were respectively collected before and after the disinfection.Geobacillus stearothermophilus was used as the biological indicator and placed at various points within the air-disinfected wards to evaluate the disinfection level.The environmental sampling results and distribution of bacteria were observed and compared.RESULTS The qualified rates of disinfection of the object surfaces were 95.56％(86/90)and 98.89％(89/90)respectively for the low and high concentratioins of hydrogen peroxide disinfecting wipes,and there was no significant difference in the disinfection effect.Totally 120 strains of pathogens were isolated from unqualified samples before the disinfection,among which gram-negative bacteria(69.17％)were dominant,and the isolation rate of multidrug-resistant or-ganisms was 22.50％(27/120);only 1 strain of carbapenem-resistant Acinetobacter baumannii was isolated after the disinfection.The qualified rate of disinfection of air in the wards was 96.00％by 7.5％hydrogen peroxide dry mist disinfection device,the average bacterial colony counts in the air were 2 CFU/(5 min·vsl)after the dis-infection,and the killing rate of Geobacillus stearothermophilus was 100.00％by the air disinfection.CONCLUSION The hydrogen peroxide disinfectant can meet the requirement for terminal disinfection of the wards of the medical institutions,and it is portable and highly efficient.

Objective To investigate the application of low-dose computed tomography virtual colonoscopy(LDCTVC)in colorec-tal tumor.Methods Forty-seven colorectal tumor were given low-dose CT abdominal scan(low-dose group),15 patients with normal body mass index(BMI)who received routine-dose CT abdominal scan at the same period(routine-dose group).Volume CT dose index(CTDIvol),dose length product(DLP),virtual colonoscopy and optical colonoscopy results were recorded.Results The effective dose with normal BMI was(2.86±0.47)mSv and(4.87±1.15)mSv in the low-dose and routine-dose groups,respectively.The CTDIvol and DLP between the two groups were statistically significant(P＜0.05).There were 14 cases of true positive,4 cases of false positive,5 cases of false negative and 24 cases of true negative in the low-dose group.The sensitivity,specificity and Kappa value of LDCTVC in the diagnosis of colorectal mucosal lesions were 73.7％,85.7％,and 0.6.Conclusion LDCTVC can reduce the effective dose by 50％and has a good diagnostic value for colorectal mucosal lesions,which can make up for the deficiency of colonoscopy and make accurate judgment of extra-mucosal lesions of the bowel wall.

Objective To assess pregnancy outcome and pregnancy related concerns in Takayasu arteritis (TA) patients.Methods We analyzed 68 female patients with TA retrospectively from Xijing hospital.Data on the number of pregnancies,births and pregnancy outcomes before and after disease onset were retrieved from medical charts,patient questionnaires and the department of Obstetrics in Xijing Hospital.Data on pregnancy related concerns were gathered from patient questionnaires.Results Altogether,68 women in the TA study cohort had 106 pregnancies,73 (in 41 patients) before disease onset and 33 (in 28 patients) after disease onset.There were no difference in the frequencies of miscarriages,induced abortions and maternal complications before and after TA onset.Pregnancy related hypertension was seen in 4.7％ of the TA patients compared to 2.0％ (x2=1.238,P＞0.05) of the reference cohort from the department of Obstetrics in Xijing Hospital and preeclampsia/eclampsia in 4.7％ of the TA patients compared to 2.8％ of the reference cohort (x2=1.835,P＞0.05).The mean gestational age at delivery in pregnancies after TA onset was (37±6) weeks compared to (39±4) weeks in the reference cohort (x2=14.665,P＜0.01).Caesarian sections were more frequent in deliveries after TA onset (36％) than in the reference cohort (15％) (x2=13.322,P＜0.01).86％ of the TA patients had pregnancy related concerns.Of these concerns,72％ was about passing the disease to offsprings.Conclusion In this population based TA cohort,the maternal and fetal outcomes are favorable.Pregnancy related concerns are very popular in TAK patients.

Objective: To explore the relation between platelet-to-lymphocyte ratio (PLR) or neutrophil-to-lymphocyte ratio (NLR) with disease activity in Takayasu arteritis (TA) patients. Methods: Present retrospective study involved 289 patients with TA, who were hospitalized in our department between January 2010 and October 2017, and 280 age and gender matched healthy controls,who underwent thealth examination in our health examination center during the same period (control group). TA patients were further divided into active and inactive groups (180 and 109 cases respectively) according to Kerr scores. The clinical data were compared between groups. Pearson correlation analysis was used to evaluate the relationship between PLR or NLR and disease activity (Kerr score or C-reactive protein or erythrocyte sedimentation rate). Receiver operating characteristic (ROC) curve was employed to judge the cut-off value of disease activity for TA patients. Results: PLR and NLR were significantly higher in TA group than in control group(137.33 (97.38, 193.37) vs. 120.55 (96.86, 144.60) and 2.38 (1.76, 3.57) vs. 1.66 (1.35, 2.08) , respectively, all P<0.001). PLR and NLR were significantly higher in active TA group than in inactive TA group (163.43 (123.64, 224.15) vs. 110.53 (84.22, 147.24) and 2.59 (1.96, 3.94) vs. 1.95 (1.53, 2.86) respectively, all P<0.001). PLR and NLR of active group were significantly decreased after 6 months treatment (164.05 (123.29, 226.29) vs. 104.67 (77.22, 138.43) and 2.58 (1.96, 3.91) vs. 2.15 (1.67, 2.60) respectively, all P<0.001). PLR was positively correlated with Kerr score (r=0.439, P<0.001), C-reactive protein (r=0.328, P<0.001) and erythrocyte sedimentation rate (r=0.410, P<0.001). NLR also exhibited a positive relationship with Kerr score (r=0.235, P<0.001), C-reactive protein (r=0.169, P=0.005) and erythrocyte sedimentation rate (r=0.123, P=0.037). A PLR level of 176.709 was shown to be the best predictive cut-off value for TA disease activity (sensitivity 44.6%, specificity 93.0%, and area under the curve=0.766).A NLR level of 2.128 was shown to be the best predictive cut-off value for TA disease activity (sensitivity 70.9%, specificity 47.7%, and area under the curve=0.691). Conclusion PLR and NLR are useful markers for predicting disease activity of TA patients.

Aim To investigate the effect of PLK1 on epithelial-mesenchymal transition (EMT)of human e-sophageal squamous cell carcinoma (ESCC)cells TE-1 5 and its relevant molecular mechanisms.Methods PLK1 overexpressed ESCC cells and control vector were used as the experimental cells.The expression of EMT-related protein markers E-cadherin and vimentin were measured by Western blot.vimentin mRNA was measured by Real-time PCR.Total cellular protein and nuclear protein were respectively extracted,and then they were used to detect the expression of β-catenin by Western blot.β-catenin siRNA and non-specific siR-NA were transiently transfected into the cell clones overexpressed PLK1 ,and then vimentin was detected by Western blot.β-catenin protein degradation com-plex was detected by immunoprecipitation and Western blot.Results The mesenchymal marker vimentin was distinctively upregulated and the epithelial marker E-cadherin was distinctively downregulated in the cell clones overexpressed PLK1 ,compared with those in the vector clones.This indicated that EMT occurred in ESCC cells.vimentin mRNA was also markedly in-creased.In the cell clones overexpressed PLK1 ,β-catenin were both elevated from the total cells and the nucleus.The expression of vimentin was reduced whenβ-catenin was knocked down.APC and GSK-3βwere both reduced from Axin immunoprecipitate in the cell clones overexpressed PLK1 .Conclusion PLK1 up-regulates vimentin and promotes EMT in ESCC cells probably by inhibiting the formation of protein degrada-tion complex and stabilizing β-catenin.