Protective effects of twin drug ST-11 against PC12 cell injury induced by oxygen-glucose deprivation/reperfusion and its mechanism / 中国药房

OBJECTIVE To study the protective effects of ligustrazine-scutellarein twin drug ST-11 on rat adrenal medullary pheochromocytoma PC12 cell injury induced by oxygen-glucose deprivation/reperfusion （OGD/R） and its mechanism. METHODS PC12 cells were divided into blank group， model group， nimodipine group （positive control， 5 μmol/L） and different concentration groups of ST-11 （5， 10， 20 μmol/L）. After 24 hours of pre-administration intervention， all the other groups except the blank group were cultured in glucose-free DMEM culture medium containing 10 mmol/L Na2S2O4 for 4 hours with glucose deficiency and hypoxia. After 4 hours of glucose and oxygen re-introduction， the survival rate of cells in each group， the contents of lactate dehydrogenase （LDH）， catalase （CAT）， glutathione （GSH）， malondialdehyde （MDA） and superoxide dismutase （SOD） in cell supernatant， apoptosis rate， the levels of reactive oxygen species （ROS） and mitochondrial membrane potential （MMP）， the protein expressions of B-cell lymphoma 2 related X protein （Bax）， B-cell lymphoma 2 （Bcl-2） and caspase-3 were all detected in each group. RESULTS Compared with blank group， the cell survival rate， the contents of CAT， GSH and SOD in cell supernatant， MMP level， relative expression of Bcl-2 and Bcl-2/Bax ratio in model group decreased significantly （P＜0.05）， while the contents of LDH and MDA， ROS level， apoptosis rate， relative expressions of Bax and caspase-3 were significantly increased （P＜0.05）. Compared with model group， above indexes of ST-11 groups （except for the protein expression of caspase-3 in 5 μmol/L ST-11 group） were reversed signifi-cantly （P＜0.05）. CONCLUSIONS ST-11 has a certain protec-tive effect on OGD/R-injured PC12 cells， and its effects may be related to reduction of oxidative stress and inhibition of cell apoptosis.

Development of a double-antibody sandwich ELISA targeting the receptor binding domain of TcdB toxin of ST11 type Clostridium difficile of porcine origin / 生物工程学报

Clostridium difficile is an important zoonotic intestinal pathogen, which is widely present in humans and a variety of animals. The ST11 type C. difficile is one of the most widespread and harmful subtypes in the world. As a large country in pig farming, China lacks efficient methods for detecting C. difficile of porcine origin, leaving hidden dangers for the prevention and control of C. difficile. The aim of this study was to develop a specific and sensitive double-antibody sandwich ELISA for the epidemiological investigation of ST11 type C. difficile of porcine origin. Firstly, a 97 kDa receptor binding domain (RBD) was expressed in a prokaryotic host and purified. A hybridoma cell line AE2D3 capable of stably secreting monoclonal antibody targeting the RBD was screened, and the antibody subtype was determined to be IgG2b (κ). Secondly, a double antibody sandwich ELISA method was developed, where the monoclonal antibody targeting the RBD was used as a detection antibody, and the rabbit polyclonal antibody was used as a capture antibody. The chessboard method was used to determine the matching concentration of the capture antibody and the detection antibody, the antigen coating conditions, the blocking conditions, the incubation conditions for detection antibody and samples to be tested, as well as the reaction conditions of HRP-conjugated and reaction conditions of TMB chromogenic solution. The negative cutoff OD450 was 0.152, and no cross-reaction with 13 strains of non-ST11 type C. difficile was found. The minimum detection concentration of RBD was 8.83 ng/mL. This specific and sensitive double-antibody sandwich ELISA provides a reliable serological detection method for epidemiological investigation of the ST11 type C. difficile in pig industry.

First characterization of K. pneumoniae ST11 clinical isolates harboring blaKPC-3 in Latin America / Primera caracterización de aislamientos clínicos de K. pneumoniae ST11 portadoresde blaKPC-3en América Latina

Abstract Antimicrobial resistance due to carbapenemase production in Enterobacteriaceaeclinical isolates is a global threat. Klebsiella pneumoniae harboring the blaKPCgene is one ofthe major concerns in hospital settings in Latin America.The aim of this study was to characterize the antibiotic resistance mechanisms and to typifyfour carbapenem-resistant K. pneumoniae clinical isolates from the city of Manizales, Colombia.We identified blaKPC-3in all four isolates by polymerase chain reaction and subsequentsequencing. The plasmid-mediated quinolone resistance genes qnrB19-like and aac(6)Ib-cr;fosfomycin resistance gene fosA and an insertion sequence IS5-like in mgrB (colistin resistance)were also detected. Sequence types ST11 with capsular type wzi75, and ST258 with wzi154,were characterized. The blaKPC-3gene was mobilized in a 100-kb IncFIB conjugative plasmidwith vagCD toxin-antitoxin system.This work reports multiple resistance genes in blaKPC-producing K. pneumoniae and the firstoccurrence of ST11 clinical isolates harboring blaKPC-3in Latin America.

Resumen La resistencia a antibióticos mediada por la producción de carbapenemasas en aislamientos clínicos de Enterobacteriaceae es una amenaza mundial. Klebsiella pneumoniae portador de blaKPC es uno de los mayores problemas a nivel hospitalario en Latinoamérica. El objetivo de este estudio fue caracterizar los mecanismos de resistencia antibiótica y tipificar cuatro aislamientos clínicos de K. pneumoniae resistentes a carbapenems obtenidos en la ciudad de Manizales, Colombia. Se identificó blaKPC-3 en todos los aislamientos mediante reacción en cadena de polimerasa y secuenciación. También se detectaron los genes de resistencia transferible a quinolonas qnrB19-like y aac(6')Ib-cr y a fosfomicina fosA, y la secuencia de inserción /S5-like en mgrB (asociada a la resistencia a colistina). Se caracterizaron los secuenciotipos ST11 (cápsula wzi75) y ST258 (cápsula wzi154). Se comprobó que blaKPC-3 fue movilizado por un plásmido conjugativo IncFIB-vagCD de 100kb. En este trabajo se reportan múltiples genes de resistencia en K. pneumoniae productor de blaKPC y se describen por primera vez aislamientos clínicos ST11 productores de blaKPC-3 en Latinoamérica.