Objective:To analyze the carriage status, subtype distribution and flanking gene sequence characteristics of oxacillinases (OXA enzyme) in 241 clinical strains of Pseudomonas aeruginosa, and assess their roles in the drug resistance of Pseudomonas aeruginosa and ability to horizontally transfer across species. Methods:Clinical P. aeruginosa isolates were collected from four hospitals in Sanya, Tangshan, Zhangjiakou, and Beijing. The prevalence of oxacillinases and their flanking gene sequences was analyzed by whole-genome sequencing (NGS) and bioinformatic approaches. Results:A total of 241 isolates of P. aeruginosa were gathered, and 35 blaOXA subtypes were identified through screening of 252 blaOXA genes. These genes were classified into three subfamilies: blaOXA-50-like (241, 95.6%), blaOXA-1-like (9, 3.6%) and blaOXA-10-like (2, 0.8%). Among these, 11 subtypes (11, 31.4%) were novel blaOXA subtypes. Nine of these belonged to the blaOXA-50-like subfamily and were designated as blaOXA-1244, blaOXA-1245, blaOXA-1246, blaOXA-1250, blaOXA-1252, blaOXA-1253, blaOXA-1254, blaOXA-1255, and blaOXA-1256. The remaining two belonged to the blaOXA-10-like subfamily and were named blaOXA-1247 and blaOXA-1248. Compared to the amino acid sequence of OXA-10, the newly identified subtype OXA-1247 exhibited a mutation at position 117, where a valine was replaced by a leucine. This change was thought to improve the enzyme′s ability to hydrolyze carbapenems. In the analysis of the flanking sequences of the blaOXA genes, Class I integrons were identified in four bacterial strains. The variable regions of these integrons carried three distinct patterns of resistance gene cassettes: aac( 6′) -Ib-blaOXA-1247-ant( 3′′) -Ia, aac( 6′) -Ib-blaOXA-1248 and aac( 6′) -Ib- blaIMP-45-blaOXA-1-catB3. Among these, the strain BJ2326 carried a class I integron that was connected to the downstream IS CR1 element to form a composite class I integron structure, additionally carrying the resistance gene blaPER-1. Out of the 223 non-wild-type P. aeruginosa strains, 127 strains exhibited non-wild-type profiles to the four beta-lactam antibiotics MEM, CAZ, FEP, and TZP, with the combination of MEM+CAZ+FEP being the most prevalent, representing 57.0% of the total. Conclusions:The blaOXA genes in 241 clinical P. aeruginosa strains showed diversity. Some blaOXA genes had a co-transfer risk with the metallo-β-lactamase resistance gene blaIMP-45. Among the 11 newly discovered blaOXA subtypes, the new subtype OXA-1247 may have carbapenemase activity and potential for horizontal transfer.

Objective To investigate the correlations of serum levels of endothelial cell-specific molecule-1(ESM-1,also known as endocan),interleukin(IL)-1α,and human chondroglycan pro-tein-39(also known as YKL-40)with disease severity and prognosis in children with recurrent respira-tory infections(RRI).Methods A total of 86 children with RRI were prospectively enrolled as case group and divided into mild(37 cases),moderate(31 cases),and severe(18 cases)groups based on disease severity,and divided into good prognosis(64 cases)and poor prognosis(22 cases)groups based on prognosis.Additionally,94 healthy children who underwent physical examinations during the same period were selected as control group.Serum levels of endocan,IL-1α,and YKL-40 were measured using enzyme-linked immunosorbent assay(ELISA)in all children.Spearman's correla-tion analysis was used to assess the correlation between serum levels of endocan,IL-1α,and YKL-40 and disease severity in children with RRI.Multivariate Logistic regression analysis was conducted to explore the factors influencing the prognosis of children with RRI.Receiver operating characteristic(ROC)curves were used to evaluate the predictive value of serum endocan,IL-1α,and YKL-40 for the prognosis of children with RRI.Results The serum levels of endocan,IL-1α,and YKL-40 in the case group were higher than those in the control group(P＜0.05).The serum levels of en-docan,IL-1α,and YKL-40 in the moderate and severe groups were higher than those in the mild group,and the levels in the severe group were higher than those in the moderate group(P＜0.05).The serum levels of endocan,IL-1α,and YKL-40 in the poor prognosis group were higher than those in the good prognosis group(P＜0.05).Serum levels of endocan,IL-1α,and YKL-40 were significantly positively correlated with disease severity in children with RRI(r=0.407,0.493,0.452,respectively;P＜0.001).Multivariate Logistic regression analysis showed that serum en-docan(OR=1.412),IL-1α(OR=1.583),and YKL-40(OR=1.259)were independent influen-cing factors for the prognosis of children with RRI(P＜0.05).The ROC curve showed that the area under the curve for the combined prediction of poor prognosis in children with RRI by serum en-docan,IL-1α,and YKL-40 was 0.925,which was significantly larger than that for endocan,IL-1α,and YKL-40 alone.Conclusion Serum levels of endocan,IL-1α,and YKL-40 are closely related to disease severity and prognosis in children with RRI,and their combined detection has high predictive value for the prognosis of children with RRI.

Objective:To analyze the carriage status, subtype distribution and flanking gene sequence characteristics of oxacillinases (OXA enzyme) in 241 clinical strains of Pseudomonas aeruginosa, and assess their roles in the drug resistance of Pseudomonas aeruginosa and ability to horizontally transfer across species. Methods:Clinical P. aeruginosa isolates were collected from four hospitals in Sanya, Tangshan, Zhangjiakou, and Beijing. The prevalence of oxacillinases and their flanking gene sequences was analyzed by whole-genome sequencing (NGS) and bioinformatic approaches. Results:A total of 241 isolates of P. aeruginosa were gathered, and 35 blaOXA subtypes were identified through screening of 252 blaOXA genes. These genes were classified into three subfamilies: blaOXA-50-like (241, 95.6%), blaOXA-1-like (9, 3.6%) and blaOXA-10-like (2, 0.8%). Among these, 11 subtypes (11, 31.4%) were novel blaOXA subtypes. Nine of these belonged to the blaOXA-50-like subfamily and were designated as blaOXA-1244, blaOXA-1245, blaOXA-1246, blaOXA-1250, blaOXA-1252, blaOXA-1253, blaOXA-1254, blaOXA-1255, and blaOXA-1256. The remaining two belonged to the blaOXA-10-like subfamily and were named blaOXA-1247 and blaOXA-1248. Compared to the amino acid sequence of OXA-10, the newly identified subtype OXA-1247 exhibited a mutation at position 117, where a valine was replaced by a leucine. This change was thought to improve the enzyme′s ability to hydrolyze carbapenems. In the analysis of the flanking sequences of the blaOXA genes, Class I integrons were identified in four bacterial strains. The variable regions of these integrons carried three distinct patterns of resistance gene cassettes: aac( 6′) -Ib-blaOXA-1247-ant( 3′′) -Ia, aac( 6′) -Ib-blaOXA-1248 and aac( 6′) -Ib- blaIMP-45-blaOXA-1-catB3. Among these, the strain BJ2326 carried a class I integron that was connected to the downstream IS CR1 element to form a composite class I integron structure, additionally carrying the resistance gene blaPER-1. Out of the 223 non-wild-type P. aeruginosa strains, 127 strains exhibited non-wild-type profiles to the four beta-lactam antibiotics MEM, CAZ, FEP, and TZP, with the combination of MEM+CAZ+FEP being the most prevalent, representing 57.0% of the total. Conclusions:The blaOXA genes in 241 clinical P. aeruginosa strains showed diversity. Some blaOXA genes had a co-transfer risk with the metallo-β-lactamase resistance gene blaIMP-45. Among the 11 newly discovered blaOXA subtypes, the new subtype OXA-1247 may have carbapenemase activity and potential for horizontal transfer.

Tissue inhibitor of metalloproteinases-2 (TIMP-2) inhibits tumor migration and invasion. Obtaining TIMP-2 protein is conducive to a comprehensive and in-depth study of its function and mechanism in tumorigenesis and development. We collected human TIMP-2 protein through prokaryotic expression in vitro. We expressed, purified and characterized human TIMP-2 protein. First, the human TIMP-2 gene was cloned from the cDNA obtained by reverse transcription of total RNA of human lung cancer A549 cells, and constructed to pET28a vector. The recombinant plasmid pET28a-TIMP-2 was transformed into Escherichia coli BL21(DE3) after restriction endonuclease digestion and sequencing analysis. The expression of TIMP-2 protein was induced by isopropyl-β-D-thiogalactoside (IPTG), and the expression conditions were optimized. After purification by nickel affinity column, the fusion protein His-TIMP-2 was identified by Western blotting method and its biological activity was detected by gelatin zymography. The fusion protein His-TIMP-2 existed in the form of inclusion body in E. coli. In a certain range, the concentration of IPTG had no significant effect on the expression amount of His-TIMP-2. But in this expression system, induction temperature and time were the key parameters, and the expression amount of His-TIMP-2 in E. coli increased with the increase of induction temperature. The purified and refolded fusion protein could effectively inhibit the activity of matrix metalloproteinases expressed by human lung cancer A549 cells. The acquisition of active fusion protein lays a foundation for further study of the function and mechanism of human TIMP-2, and is of great significance for tumor therapy.
Cloning, Molecular ; Escherichia coli/genetics* ; Humans ; Recombinant Fusion Proteins/genetics* ; Recombinant Proteins ; Tissue Inhibitor of Metalloproteinase-2/genetics*

Objective To identify the half-sibling relationship by comprehensive using three different methods. Methods STR genotype was performed on A, A's mother, B and B's mother by using PowerPlex21 kit, AGCU Expressmarker 21+1 kit, Microreader 23sp-B kit and AGCU X-19 STR kit respectively. Based on the results of STR genotype and X-STR, we determined half-sibling relationship by ITO, discriminant function analysis and IBS. Results HIS was between 1.36×102and 2.09×105in ITO which indicated that A and B had the same father. The IBS and discriminant function analysis also had the same conclusion. Conclusion Comprehensive using multiple methods can obtain reliable result to identify the half-sibling relationship from the same father.

Objective To investigate the mutation phenomenon of 20 autosomal STR loci in Henan Han population. Methods A total of 3011 parentage confirmed cases were collected to screen mutation events, ascertain the source of mutation, calculate mutation rate, analyze mutation rules and compare with the mutation condition of populations in different regions. Results 76 mutation events were observed in 19 STR loci, the average and accumulative mutation rate reached to 0.08% and 1.6629%, respectively. The ration of paternal versus maternal mutation was 8:1. Mutation rates of Penta E and D12S391 loci in Henan Han population were lower than the Han population of northern China(P<0.05); the mutation rate of CSF1PO locus were lower than Guangdong population and Yunan Han population(P<0.05); the mutation rates of D6S1043 and D12S391 loci were lower than Guangdong population(P<0.05). Conclusion STR mutation events were common in paternity testing. Region differences among mutation rate were significant.