Genetic factors related to the widespread dissemination of ST11 extensively drug-resistant carbapenemase-producing Klebsiella pneumoniae strains within hospital / 中华医学杂志(英文版)

BACKGROUND@#Carbapenemase-producing Klebsiella pneumoniae (CP-Kp) poses distinct clinical challenges due to extensively drug resistant (XDR) phenotype, and sequence type (ST) 11 is the most dominant blaKPC-2-bearing CP-Kp clone in China. The purpose of this current retrospective study was to explore the genetic factors associated with the success of XDR CP-Kp ST11 strains circulated in the intensive care unit (ICU) of a Chinese tertiary hospital.@*METHODS@#Six ST11 XDR CP-Kp strains were identified between May and December 2014 and validated by minimum inhibitory concentration examination, polymerase chain reaction, and pyrosequencing. The six ST11 XDR CP-Kp, as well as three multi-drug resistant (MDR) and four susceptible strains, were sequenced using single-molecule real-time method. Comprehensively structural and functional analysis based on comparative genomics was performed to identify genomic characteristics of the XDR ST11 CP-Kp strains.@*RESULTS@#We found that ST11 XDR blaKPC-2-bearing CP-Kp strains isolated from inpatients spread in the ICU of the hospital. Functionally, genes associated with information storage and processing of the ST11 XDR CP-Kp strains were more abundant than those of MDR and susceptible strains, especially genes correlative with mobile genetic elements (MGEs) such as transposons and prophages. Structurally, eleven large-scale genetic regions taken for the unique genome in these ST11 XDR CP-Kp strains were identified as MGEs including transposons, integrons, prophages, genomic islands, and integrative and conjugative elements. Three of them were located on plasmids and eight on chromosomes; five of them were with antimicrobial resistance genes and eight with adaptation associated genes. Notably, a new blaKPC-2-bearing ΔΔTn1721-blaKPC-2 transposon, probably transposed and truncated from ΔTn1721-blaKPC-2 by IS903D and ISKpn8, was identified in all six ST11 XDR CP-Kp strains.@*CONCLUSION@#Our findings suggested that together with clonal spread, MGEs identified uniquely in the ST11 XDR CP-Kp strains might contribute to their formidable adaptability, which facilitated their widespread dissemination in hospital.

Analysis of expressed sequence tags (EST) from Panax quinquefolium root / 药学学报

To investigate the profile of gene expression in American ginseng (Panax quinquefolium L.) and discover its functional genes, for the first time, expressed sequence tags (EST) library of four-year-old American ginseng roots has been established. According to BLAST and Gene Ontology analysis, eleven genes, encoding cytochrome P450, glucosyltransferase, farnesyltransferase and cyclase family protein, are found to be associated with ginsenosides biosynthesis. Six other genes are obtained encoding auxin-regulated protein, auxin response factor 4 and auxin-repressed protein in the roots of American ginseng. In addition, thirteen expressed transcripts are stress-connected proteins and twelve expressed other transcripts are closely related to plant defense in four-year-old American ginseng roots. Furthermore, 62 genes no hit in BLAST and in Interproscan may be new genes. These results indicate EST is an useful tool for research on functional genomics of P. quinquefolium and it can be applied to the molecular modification of the ginsenosides biosynthetic pathway ultimately for improving the quality of American ginseng germplasm.

HLA-A, B, DRB1 gene polymorphism of Beijing population was studied by high-resolution polymerase chain reaction sequence-based typing / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the gene polymorphism of human leukocyte antigen (HLA)-A, B, DRB1 loci in the population of Beijing region, and research on the application feasibility of polymerase chain reaction sequence-based typing (PCR-SBT) method.</p><p><b>METHODS</b>PCR-SBT method was applied to determine HLA- A, B, DRB1 genotypes of 618 unrelated healthy individuals of Beijing region.</p><p><b>RESULTS</b>A total of 84 different alleles and 199 genotypes of HLA-A, 143 alleles and 366 genotypes of HLA-B, 122 alleles and 286 genotypes of HLA-DRB1 were detected.</p><p><b>CONCLUSION</b>The results showed the characteristics of HLA-A, B, DRB1 distributions, and provided more comprehensive and accurate gene data that may serve as normal reference values for all of Beijing people.</p>

Frequencies distribution of human leukocyte antigen-B27 subtypes in healthy Chinese / 中国医学科学院学报

<p><b>OBJECTIVE</b>To investigate the frequencies distribution of human leukocyte antigen (HLA)-B27 subtypes in unrelated healthy Chinese.</p><p><b>METHOD</b>Polymerase chain reaction sequence-based typing (PCRSBT) was used to determine HLA high-resolution genotypes of 825 unrelated healthy Chinese.</p><p><b>RESULTS</b>A total of 25 HLA-B27-positive individuals and 8 HLA-B27 subtypes were detected. These subtypes and their corresponding frequencies were B * 2704 (30.77%) , B * 2705 (23.08%), B * 2707 (19.23%), B * 2711 (7.69%), B * 2712 (7.69%), B * 2701 (3.85%), B * 2713 (3.85%) and B * 2721 (3.85%).</p><p><b>CONCLUSION</b>The data obtained through PCR-SBT method may serve as important reference for the research of relationship between HLA-B27 subtypes and some diseases such as ankylosing spondylitis.</p>

Exclusion of the association of five known mutations with congenital stationary nyctalopia in a large Chinese family / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To detect gene mutations associated with autosomal dominant congenital stationary night blindness(ADCSNB) in a large Chinese family.</p><p><b>METHODS</b>Genomic DNAs were extracted from peripheral blood samples of 16 affected and 14 unaffected family members. According to 5 missense mutations in 3 genes reported previously, 4 pairs of primers were designed and corresponding exons containing the five mutation sites were amplified by polymerase chain reaction. Amplified products were purified and sequenced by MegaBACE1000 capillary array electrophoresis DNA sequencer. Full field electroretinogram (ERG, ISCEV) of patients was recorded and analyzed by Roland Consult System.</p><p><b>RESULTS</b>Dark-adapted ERG showed a-wave was normal, but b-wave of the patients was markedly decreased. None of the five missense mutations were detected in 16 affected and 14 unaffected family members.</p><p><b>CONCLUSION</b>The molecular pathogenesis of ADCSNB in this family does not involve point mutations or deletions of these five sites, which indicates the heterogeneity of ADCSNB.</p>