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Objective:To analyze the biological characteristics, phylogenic features and clinical significance of SQ219 and SQ220 isolated from clinical sputum and midstream urine specimens.Methods:The culture and biochemical characteristics of the two strains were observed. VITEK2 System, drug sensitivity testing and MALDI-TOF mass spectrometry were used for bacterial identification. Phylogenetic analysis based on 16S rRNA and core genome was performed. The average nucleotide identity (ANI) based on whole genome sequences was calculated.Results:SQ219 and SQ220 were Gram-stain-negative, aerobic, catalase- and oxidase-positive, and non-motile bacteria. Their optimum growth was observed in NaCl-free medium at 30℃ and pH7. Flexirubin-type pigments were produced by SQ220 on Colombia blood agar, but not by SQ219. Both SQ219 and SQ220 were resistant to aztreonam, amikacin, tobramycin and colistin, which was consistent with the drug resistance phenotype of genus Chryseobacterium. The genome sequences of SQ219 and SQ220 were 5.08 Mb and 4.80 Mb in length, and the G+ C contents were 36.72% and 36.36%, respectively. Both strains carried β-lactam resistance gene ( blaCGA). 16S rRNA phylogenetic analysis showed that SQ219 and SQ220 were closely related to Chryseobacterium gambrini DSM18014 T with the similarities of 98.93% and 98.36%, respectively. Core genome phylogenetic analysis revealed that SQ219 and SQ220 were highly homologous to Chryseobacterium gambrini DSM18014 T. However, the ANI values between the two strains and Chryseobacterium gambrini DSM18014 T were 92.49% and 93.27%, respectively, below the threshold for prokaryotic species identification. Conclusions:Based on the phenotypic and phylogenetic data, SQ219 and SQ220 represent a novel species of the genus Chryseobacterium. This study would help promote the understanding of the evolution of Chrysobacterium and provide reference for the identification of new species of Chrysobacterium.
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Objective To investigate the changes of antimicrobial peptide LL-37 and C-reactive protein (CRP ) in the patients with Pseudomonas aeruginosa positive sputum culture and their mutual relation . Methods Fifty cases of Pseudomonas aeruginosa positive sputum culture and 27 cases undergoing physical ex-amination in the Guangdong Provincial Hospital of Chinese Medicine from September 2016 to May 2017 were selected as the research subjects .The level of antimicrobial peptide LL-37 was detected by double antibody sandwich ELISA and the CRP level was detected by immunoturbidimetry .Results The levels of antimicrobial peptide LL-37 and CRP in the Pseudomonas aeruginosa positive sputum culture group were significantly high-er than those in the healthy control group ,the difference was statistically significant (P< 0 .05) ,and they showed the positive correlation (r=0 .411 ,P<0 .05) .Conclusion In positive sputum culture of Pseudomonas aeruginosa ,antimicrobial peptide LL-37 and CRP levels are increased ,which has a certain clinical application value for the early diagnosis of infection .
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Objective To investigate the changes of microRNA (miR)-146a ,miR-29b expression levels and the 3 kinds of meth-ylase DNMT1 ,DNMT3a and DNMT3b levels in K562 cell lines after BCR/ABL inhibitor Gleevec treatment .Methods The half maximal inhibitory concentration(IC50 ) of Gleevec on K562 cells was detected by the MTT method .The stem loop primers method and the fluorogenic quantitative PCR were adopted to detect miRNAs and the methylase gene level .Results IC50 of Gleevec acting on K562 cells was 40 .85μmol/L .After Gleevec action ,miR-29b showed the increasing trend ,but 3 kinds of methylase expression level were decreased to some extent .Gleevec could significantly increase the miR-146a level in K562 cells(P<0 .05) .Conclusion Gleevec can influence the expression of miR-146a ,miR-29b and DNMTs levels in K562 cells .
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Objective:To study the influence of protein transduction domain (PTD)-oligomerization domain (OD)-HA fusion proteins on apoptosis of bcr/abl-positive cell lines. Methods:bcr/abl-positive cells were treated with PTD-OD-HA protein. The apoptoses of the cells were detected by flow cytometry (FCM), DNA ladder and transmission electron microscopy (TEM), and the levels of apoptosis-related genes bax and bcl-2 were detected by RT-PCR and Western blotting. Results:FCM examination demonstrated that PTD-OD-HA protein induced the apoptosis of bcr/abl-positive cells; DNA ladder showed that the classic DNA ladders appeared in BaF3-P210 and K562 cells after 48 h treatment with PTD-OD-HA proteins; the apoptoses of BaF3-P210 cells were observed by TEM; the levels of bax in mRNA and protein increased in BaF3-P210 and K562 cells, and bcl-2 decreased. Conclusion:PTD-OD-HA proteins specifically induced the apoptosis of bcr/abl positive cells.
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Objeetive To construct the cell DNA damage models for the human CML K562 cell line before or after imarlnib mesylate treatment and observe the repairing process dynamically for investigating the iniluence of imatinib mesylate on the repair function of K562 cells after cell DNA danlage.Methods The MTT assay was used to estimate the optimal pretreatment concentration of imatinib mesylate in K562 cells and Western blot was employed to evaluate the phosphorylation status in K562 cells after imatinib mesylate treatment to estimate BCR/ABL tyrosine kinase inhibition by imatinib mesylate.The comet assay was used to detect the DNA damage induced by hydrogen peroxide at various concentrations in K562 cells with or without the pretreatment of imatinib mesylate.A dynamic observation on the repairing process after cell DNA damage was made by the comet assay.Results The pretreatment by imatinib mesylate for K562 cells was optimized to be at a final concentration of 1 μmol/L for 24 h as revealed by the MTT assay additionly imatinib mesylate treatment at this concentration could effectively inhibit the phosphorylation of the BCR-ABL fusion protein at Tyr177(Deusityrate 0.100±0.018).When compared with the control group(Deusityrate 0.425±0.039),the BCR/ABL phosphorylation at Tyr177 was significantly decreased by (77. 11±5.59) % (t=4. 57,P＜0. 05). The cell DNA damage models for both imatinib mesylate-nontreated and imatinib mesylate-pretreated K562 cell groups were constructed with hydrogen peroxide treatment at a final concentration of 10 μmol/L for 10 min at 4℃ as confirmed by the comet assay. When compared with the control imatinib mesylatenontreatod K562 cell group,the time duration required for the DNA repair in imatinib mesylate-pretreated K562 cell group was significantly prolonged (F= 97.79,P＜0. 05 ). Conclusions The cell DNA damage models for the leukemic K562 cell groups before or after imatinib mesylate treatment were successfully constructed and the tyrosine kinase inhibitor imatinib mesylate for BCR/ABL fusion protein was revealed to attenuate the DNA repair capacity of the K562 cells after DNA damage.
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Objective To construct the transformed mouse BaF3-P210 cell line stably expressing BCR/ABL and to initially investigate the influence of BCR/ABL on the cell biological characteristics of BaF3 cell line. Methods The retroviral vector with bcr/abl gene was transfected into the packaging cell line. The BaF3 cells were infected with the collected viral supernatant. The transgenic BaF3-P210 cell line stably expressing BCR/ABL were screened and subcloned. The integration of the bcr/abl gene in the genome of the target cell was determined by PCR and DNA sequencing,trypan blue staining assay,flow cytometry and MTT assay. Results The bcr/abl gene was integrated into the BaF3 cell genome; RT-PCR and Western blot verified the stable expression of the bcr/abl gene and protein in the screened subclone cell line BaF3-P210. Compared with the control group,the cell proliferation rate was promoted (P
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Objective To construct a recombinant eukaryotic expression plasmid of glycosylphosphatidyl inositol(GPI)-anchored bcr/abl and explore its expression at mRNA and protein level.Methods The gene fragment encoding bcr/abl was amplified by PCR using the plasmid containing the cDNA sequence of P210 as template and then inserted into a eukaryotic expression vector pBudCE4.1.The constructed recombinant plasmid pBudCE4.1-bcr/abl was identified by restriction analysis and DNA sequencing.Lymphocytes were isolated from human peripheral blood and their total RNA was extracted.The gene fragment encoding GPI was amplified by RT-PCR using the obtained RNA as template and was inserted into the constructed recombinant plasmid pBudCE4.1-bcr/abl in order to anchor GPI and bcr/abl.The constructed recombinant plasmid pBudCE4.1-bcr/abl-GPI was transfected into COS-7 cells,and the expressions of objective fragment were detected by RT-PCR and Western blotting.Results The results of restriction analysis,PCR and DNA sequencing proved that GPI-anchored bcr/abl fusion fragment was correctly inserted into vector pBudCE4.1.The expression of bcr/abl fusion gene and fusion protein were identified in transfected COS-7 cells and on their membrane.Conclusion The recombinant plasmid pBudCE4.1-bcr/abl-GPI was successfully constructed and expressed on the membrane of COS-7 cells,which found a basis of cell immunity with GPI-anchored bcr/abl fusion gene.
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Objective To construct double expression retroviral vectors targeting chronic myeloid leukemia (CML) b3a2-type mRNA and investigate its effect on the phenotype of K562 cells. Methods The eGFP coding sequence was inserted into the retroviral vector pMSCV-neo to construct pMSCV/GFP, then H1-RNA pol III-based transcription cassettes was subcloned into it to form pMSCV/GFP-H1-BCR/ABL40AS. Two control vectors pMSCV/GFP-H1-BCR/ABL40S & pMSCV/GFP-H1-BCR/ABL80AS were constructed in addition. All these constructions were identified by restriction enzyme analysis and DNA sequencing. After that, the recombinant vectors were transferred into retrovirus packaging cell line PT67 by using lipofectamine2000, and G418 were used to select stable virus-producing cell lines. Viral titer was determined by infection of NIH3T3 cells sequentially. The cell-growth curve was assayed, cell apoptosis was checked with Annexin V-PE/7AAD double staining and flow cytometry analysis after 24-hour infection, the PKR phosphorylation was assayed by Western blotting. Results The plasmids were successfully constructed. Four cell lines, named as PT67-MSCV/GFP, PT67-40as, PT67-40s and PT67-80as were gained by G418 selection, and virus titers were 6.2?10~ 5 , 5.6?10~ 5 , 4.6?10~ 5 and 6.0?10~ 5 CFU/ml respectively. PT67-40as suspensions could induce K562 cell apoptosis by (22.54?3.19)%, significantly different from PT67-MSCV/GFP or PT67-40s (P