The objective of this study was to construct an improved thioredoxin fusion protein expression system, and express the cathelicidin-derived peptide, Lf-CATH2. The improved fusion vector Lf-CATH2-pET32α(-TS) was successfully constructed by firstly deleting the thrombin site and S tag from the pET-32α vector, then inserting the Lf-CATH2 plus a thrombin site instead. Afterwards, Lf-CATH2 was expressed in Escherichia coli as fusion protein. After the cleavage by thrombin, Lf-CATH2 was released and subsequently separated using affinity chromatography. The antimicrobial activity of purified Lf-CATH2 was also examined. The improved expression vector significantly increased enzyme cleavage efficiency by 37%, and Lf-CATH2 could be expressed in high yield and maintain the biological activity. This novel thioredoxin fusion protein expression system enables a quick production of high-yield bioactive cationic peptides like cathelicidins.
Cathelicidins ; biosynthesis ; Chromatography, Affinity ; Escherichia coli ; Genetic Vectors ; Recombinant Fusion Proteins ; biosynthesis ; Thioredoxins ; genetics

In order to study genetic variation diversity of porcine circovirus type 2 (PCV2) strains in Shanxi,the genomic sequences of nine PCV2 strains including SXQX,SXCZ,SXTY2,SXJC,SXJX,SXLL,SXPY,SXPG and SXXY recently isolated from some areas of Shanxi from 2013 to 2016,was cloned,sequenced and received by GenBank.The amplified PCV2 genomic sequences,ORF2 sequences and Cap protein amino acid of these nine strains were analysed and compared with those of published 28 PCV2 strains by DNAStar,drawing phylogenetic tree.The results showed that the genomic sequences of SXJX,SXJC and SXXY PCV2 strains were 1 768 bp,and the others were 1 767 bp,which accounted for 33％ and 67％,respectively.The homologies of nucleotide sequences of the nine strains were 94.7％-99.8％,the homologies of nucleotide sequences of the nine strains with the 28 isolates from different regions of the world PCV strain were 93.9％-99.9％,and the homologies of nucleotide sequences of the nine strains with the domestic vaccine strains were 95.1％-99.8％.The phylogenetic analysed that SXJX,SXJC and SXXY belonged to genotype PCV-2D,SXLL,SXPY and SXCZ belonged to genotype PCV-1C,and SXTY14,SXPG and SXQX belonged to genotype PCV-1A/1B.Thus it proved that the epidemic strain of PCV2 was mainly PCV-2b in Shanxi.The homologies of ORF2 nucleotide sequences and Cap amino acid of the nine strains were 90.0％-100.0％ and 87.1 ％-100.0％ respectively,the homologies of ORF2 nucleotide sequences and Cap amino acid of the nine strains with the 28 isolates from different regions of the world PCV strain were 87.6％-100.0％ and 84.1％-100.0％ respectively,and the homologies of ORF2 nucleotide sequences and Cap amino acid of the nine strains with the domestic vaccine strains were 91.0％-100.0％ and 89.3％-100.0％ respectively.The Cap amino acids of SXQX,SXJX,SXTY14,SXPG,SXJC and SXXY PCV2 were 233,ORF2 of SXQX,SXTY14 and SXPG located at 1 033-1 734 bp,ORF2 of SXXY,SXJX and SXJC located at 1 033-1 734 bp,and the Cap amino acids of SXCZ,SXLL and SXPY PCV2 were 234,ORF2 of them located at 1 030-1 734 bp,in addition,the positions of 1 030-1 734 bp were more three bases TCA than other ORF2 genome sequence of 1 767 bp,resulting in increasing a K (Lys) of amino acid sequencein at the 234 position.Also Cap protein of 9 PCV2 strains showed more amino acid variation in addition to the only high-ly conserved glycosylation sites (NYS) (pp.143-145 amino acid).It provided theoretical basis for the PCV2 immune prevention of research in Shanxi,and the data of basic theory of molecular pathogenesis of PCV2.

In recent years, cancer has become a major concern in relation to human morbidity and mortality. Anticancer peptides (ACPs) are the bioactive peptide with antitumor activity and found in many organisms, including mammals, amphibians, insects, plants and microorganisms. ACPs have been suggested as promising agents for antitumor therapy due to their numerous advantages over traditional chemical agents such as low molecular masses, relatively simple structures, greater tumor selectivity, fewer adverse reactions, ease of absorption, a variety of routes of administration and low risk for inducing multi-drug resistance. Combining with the related research in our group, we summarized the mechanisms of ACPs to provide some directions for research and development of peptide-based anticancer drugs.
Animals ; Antineoplastic Agents ; Humans ; Neoplasms ; Peptides

Objective: To describe the distribution and drug resistance of pathogens at hematology department of Jiangsu Province from 2014 to 2015 to provide reference for empirical anti-infection treatment. Methods: Pathogens were from hematology department of 26 tertiary hospitals in Jiangsu Province from 2014 to 2015. Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or agar dilution method. Collection of drug susceptibility results and corresponding patient data were analyzed. Results: The separated pathogens amounted to 4 306. Gram-negative bacteria accounted for 64.26%, while the proportions of gram-positive bacteria and funguses were 26.99% and 8.75% respectively. Common gram-negative bacteria were Escherichia coli (20.48%) , Klebsiella pneumonia (15.40%) , Pseudomonas aeruginosa (8.50%) , Acinetobacter baumannii (5.04%) and Stenotropho-monas maltophilia (3.41%) respectively. CRE amounted to 123 (6.68%) . Common gram-positive bacteria were Staphylococcus aureus (4.92%) , Staphylococcus hominis (4.88%) and Staphylococcus epidermidis (4.71%) respectively. Candida albicans were the main fungus which accounted for 5.43%. The rates of Escherichia coli and Klebsiella pneumonia resistant to carbapenems were 3.5%-6.1% and 5.0%-6.3% respectively. The rates of Pseudomonas aeruginosa resistant to tobramycin and amikacin were 3.2% and 3.3% respectively. The resistant rates of Acinetobacter baumannii towards tobramycin and cefoperazone/sulbactam were both 19.2%. The rates of Stenotrophomonas maltophilia resistant to minocycline and sulfamethoxazole were 3.5% and 9.3% respectively. The rates of Staphylococcus aureus, Enterococcus faecium and Enterococcus faecalis resistant wards vancomycin were 0, 6.4% and 1.4% respectively; also, the rates of them resistant to linezolid were 1.2%, 0 and 1.6% respectively; in addition, the rates of them resistant to teicoplanin were 2.8%, 14.3% and 8.0% respectively. Furthermore, MRSA accounted for 39.15% (83/212) . Conclusions Pathogens were mainly gram-negative bacteria. CRE accounted for 6.68%. The rates of Escherichia coli and Klebsiella pneumonia resistant to carbapenems were lower compared with other antibacterial agents. The rates of gram-positive bacteria resistant to vancomycin, linezolid and teicoplanin were still low. MRSA accounted for 39.15%.