目的1株mphA和mcr-1阳性鼠伤寒沙门菌的鉴定及耐药特征分析;方法分离自4岁腹泻患者粪便样本中的1株鼠伤寒沙门菌,使用沙门菌血清凝集法进行菌株鉴定,质谱法复核鉴定结果;使用微量肉汤稀释法进行药敏试验;通过全基因组测序及耐药基因注...目的1株mphA和mcr-1阳性鼠伤寒沙门菌的鉴定及耐药特征分析;方法分离自4岁腹泻患者粪便样本中的1株鼠伤寒沙门菌,使用沙门菌血清凝集法进行菌株鉴定,质谱法复核鉴定结果;使用微量肉汤稀释法进行药敏试验;通过全基因组测序及耐药基因注释鉴定菌株所携带的耐药基因;通过质粒测序及生信分析进行质粒类型鉴定、质粒耐药基因、插入子等注释及质粒结构分析;通过质粒接合转移试验评估质粒的水平转移能力。结果药敏试验结果显示分离株对包括阿奇霉素、多黏菌素、头孢曲松和环丙沙星等临床常用抗生素药物耐药。耐药基因鉴定结果显示:该分离株携带包括大环内酯类抗性基因mphA,多黏菌素抗性基因mcr-1在内的12类45个耐药基因及1个氟喹诺酮类耐药点突变gyr A S83F。质粒测序分析结果显示:该菌株携带一个260,008bp大小的Inc HI2型质粒,该质粒携带包括mphA基因和mcr-1基因在内的19个耐药基因,15种插入子,4种转座子。质粒接合转移实验结果显示该质粒可以在肠杆菌目细菌之间水平转移。结论研究结果为临床治疗鼠伤寒沙门菌感染中合理使用抗生素以及有效预防、控制耐阿奇霉素、多黏菌素鼠伤寒沙门菌的传播提供了科学依据。展开更多
Cancer-associated fibroblasts(CAFs)are one of the most abundant stromal cells in the tumor microenvironment which mediate desmoplastic response and are the primary driver for an immunosuppressive microenvironment,lead...Cancer-associated fibroblasts(CAFs)are one of the most abundant stromal cells in the tumor microenvironment which mediate desmoplastic response and are the primary driver for an immunosuppressive microenvironment,leading to the failure of triple-negative breast cancer(TNBC)immunotherapy.Therefore,depleting CAFs may enhance the effect of immunotherapy(such as PD-L1 antibody).Relaxin(RLN)has been demonstrated to significantly improve transforming growth factor-β(TGF-β)induced CAFs activation and tumor immunosuppressive microenvironment.However,the short half-life and systemic vasodilation of RLN limit its in vivo efficacy.Here,plasmid encoding relaxin(pRLN)to locally express RLN was delivered with a new positively charged polymer named polymeric metformin(PolyMet),which could increase gene transfer efficiency significantly and have low toxicity that have been certified by our lab before.In order to improve the stability of pRLN in vivo,this complex was further formed lipid poly-γ-glutamic acid(PGA)/PolyMetpRLN nanoparticle(LPPR).The particle size of LPPR was 205.5±2.9 nm,and the zeta potential was+55.4±1.6 mV.LPPR displayed excellent tumor penetrating efficacy and weaken proliferation of CAFs in 4T1luc/CAFs tumor spheres in vitro.In vivo,it could reverse aberrantly activated CAFs by decreasing the expression of profibrogenic cytokine and remove the physical barrier to reshape the tumor stromal microenvironment,which enabled a 2.2-fold increase in cytotoxic T cell infiltration within the tumor and a decrease in immunosuppressive cells infiltration.Thus,LPPR was observed retarded tumor growth by itself in the 4T1 tumor bearing-mouse,and the reshaped immune microenvironment further led to facilitate antitumor effect when it combined with PD-L1 antibody(aPD-L1).Altogether,this study presented a novel therapeutic approach against tumor stroma using LPPR to achieve a combination regimen with immune checkpoint blockade therapy against the desmoplastic TNBC model.展开更多
Conjugative transfer of antibiotic resistance genes(ARGs)by plasmids is an important route for ARG dissemination.An increasing number of antibiotic and nonantibiotic compounds have been reported to aid the spread of A...Conjugative transfer of antibiotic resistance genes(ARGs)by plasmids is an important route for ARG dissemination.An increasing number of antibiotic and nonantibiotic compounds have been reported to aid the spread of ARGs,highlighting potential challenges for controlling this type of horizontal transfer.Development of conjugation inhibitors that block or delay the transfer of ARG-bearing plasmids is a promising strategy to control the propagation of antibiotic resistance.Although such inhibitors are rare,they typically exhibit relatively high toxicity and low efficacy in vivo and their mechanisms of action are inadequately understood.Here,we studied the effects of dihydroartemisinin(DHA),an artemisinin derivative used to treat malaria,on conjugation.DHA inhibited the conjugation of the IncI2 and IncX4 plasmids carrying the mobile colistin resistance gene(mcr-1)by more than 160-fold in vitro in Escherichia coli,and more than two-fold(IncI2 plasmid)in vivo in a mouse model.It also suppressed the transfer of the IncX3 plasmid carrying the carbapenem resistance gene bla_(NDM-5)by more than twofold in vitro.Detection of intracellular adenosine triphosphate(ATP)and proton motive force(PMF),in combination with transcriptomic and metabolomic analyses,revealed that DHA impaired the function of the electron transport chain(ETC)by inhibiting the tricarboxylic acid(TCA)cycle pathway,thereby disrupting PMF and limiting the availability of intracellular ATP for plasmid conjugative transfer.Furthermore,expression levels of genes related to conjugation and pilus generation were significantly down-regulated during DHA exposure,indicating that the transfer apparatus for conjugation may be inhibited.Our findings provide new insights into the control of antibiotic resistance and the potential use of DHA.展开更多
An extensively drug-resistant(XDR)Escherichia coli strain 258E was isolated from an anal swab sample of a chicken farm of Anhui province in China.Genomic analyses indicated that the strain 258E harbors an incompatibil...An extensively drug-resistant(XDR)Escherichia coli strain 258E was isolated from an anal swab sample of a chicken farm of Anhui province in China.Genomic analyses indicated that the strain 258E harbors an incompatibility group N(IncN)plasmid pEC258-3,which co-produces bla_(CTX-M-3),bla_(KPC-2),bla_(TEM-1B),qnrS1,aac(6')-Ib-cr,dfrA14,arr-3,and aac(6')-Ib3.Multiple genome arrangement analyses indicated that pEC258-3 is highly homologous with pCRKP-1-KPC discovered in Klebsiella pneumoniae from a patient.Furthermore,conjugation experiments proved that plasmid pEC258-3 can be transferred horizontally and may pose a significant potential threat in animals,community and hospital settings.展开更多
Each possible pair of residues inβ-1,4 glucanase for disulfide formation was assessed using online websites,and four pairs L28C-S256C,Q41C-P278C,S122C-N163C and A184C-A215C were selected.Accordingly,four recombinant ...Each possible pair of residues inβ-1,4 glucanase for disulfide formation was assessed using online websites,and four pairs L28C-S256C,Q41C-P278C,S122C-N163C and A184C-A215C were selected.Accordingly,four recombinant plasmids pET28a(+)EccslH28,pET28a(+)EccslH41,pET28a(+)EccslH122 and pET28a(+)EccslH184 were prepared and transformed into E.coli to express the recombinant enzymes.Then analysis on enzymatic properties showed that T50 of the recombinant enzymes was increased from 10 min for EccslHt2 to 90 min for EccslH28 and 40 min for EccslH41 at 70℃,while their optimum pH value and pH stability were not affected,which proved that the introduction of disulfide bond improved the thermal stability ofβ-1,4 glucanase.展开更多
文摘目的1株mphA和mcr-1阳性鼠伤寒沙门菌的鉴定及耐药特征分析;方法分离自4岁腹泻患者粪便样本中的1株鼠伤寒沙门菌,使用沙门菌血清凝集法进行菌株鉴定,质谱法复核鉴定结果;使用微量肉汤稀释法进行药敏试验;通过全基因组测序及耐药基因注释鉴定菌株所携带的耐药基因;通过质粒测序及生信分析进行质粒类型鉴定、质粒耐药基因、插入子等注释及质粒结构分析;通过质粒接合转移试验评估质粒的水平转移能力。结果药敏试验结果显示分离株对包括阿奇霉素、多黏菌素、头孢曲松和环丙沙星等临床常用抗生素药物耐药。耐药基因鉴定结果显示:该分离株携带包括大环内酯类抗性基因mphA,多黏菌素抗性基因mcr-1在内的12类45个耐药基因及1个氟喹诺酮类耐药点突变gyr A S83F。质粒测序分析结果显示:该菌株携带一个260,008bp大小的Inc HI2型质粒,该质粒携带包括mphA基因和mcr-1基因在内的19个耐药基因,15种插入子,4种转座子。质粒接合转移实验结果显示该质粒可以在肠杆菌目细菌之间水平转移。结论研究结果为临床治疗鼠伤寒沙门菌感染中合理使用抗生素以及有效预防、控制耐阿奇霉素、多黏菌素鼠伤寒沙门菌的传播提供了科学依据。
基金This work was funded by the Medical and Health Science and Technology Program of Zhejiang Province(2021KY813)the National Natural Science Foundation of China(82174095)the National Natural Science Foundation of Zhejiang Province(LZ22H290001).
文摘Cancer-associated fibroblasts(CAFs)are one of the most abundant stromal cells in the tumor microenvironment which mediate desmoplastic response and are the primary driver for an immunosuppressive microenvironment,leading to the failure of triple-negative breast cancer(TNBC)immunotherapy.Therefore,depleting CAFs may enhance the effect of immunotherapy(such as PD-L1 antibody).Relaxin(RLN)has been demonstrated to significantly improve transforming growth factor-β(TGF-β)induced CAFs activation and tumor immunosuppressive microenvironment.However,the short half-life and systemic vasodilation of RLN limit its in vivo efficacy.Here,plasmid encoding relaxin(pRLN)to locally express RLN was delivered with a new positively charged polymer named polymeric metformin(PolyMet),which could increase gene transfer efficiency significantly and have low toxicity that have been certified by our lab before.In order to improve the stability of pRLN in vivo,this complex was further formed lipid poly-γ-glutamic acid(PGA)/PolyMetpRLN nanoparticle(LPPR).The particle size of LPPR was 205.5±2.9 nm,and the zeta potential was+55.4±1.6 mV.LPPR displayed excellent tumor penetrating efficacy and weaken proliferation of CAFs in 4T1luc/CAFs tumor spheres in vitro.In vivo,it could reverse aberrantly activated CAFs by decreasing the expression of profibrogenic cytokine and remove the physical barrier to reshape the tumor stromal microenvironment,which enabled a 2.2-fold increase in cytotoxic T cell infiltration within the tumor and a decrease in immunosuppressive cells infiltration.Thus,LPPR was observed retarded tumor growth by itself in the 4T1 tumor bearing-mouse,and the reshaped immune microenvironment further led to facilitate antitumor effect when it combined with PD-L1 antibody(aPD-L1).Altogether,this study presented a novel therapeutic approach against tumor stroma using LPPR to achieve a combination regimen with immune checkpoint blockade therapy against the desmoplastic TNBC model.
基金supported in part by grants from the Laboratory of Lingnan Modern Agriculture Project (NT2021006)National Key Research and Development Program of China (2022YFD1800400)。
文摘Conjugative transfer of antibiotic resistance genes(ARGs)by plasmids is an important route for ARG dissemination.An increasing number of antibiotic and nonantibiotic compounds have been reported to aid the spread of ARGs,highlighting potential challenges for controlling this type of horizontal transfer.Development of conjugation inhibitors that block or delay the transfer of ARG-bearing plasmids is a promising strategy to control the propagation of antibiotic resistance.Although such inhibitors are rare,they typically exhibit relatively high toxicity and low efficacy in vivo and their mechanisms of action are inadequately understood.Here,we studied the effects of dihydroartemisinin(DHA),an artemisinin derivative used to treat malaria,on conjugation.DHA inhibited the conjugation of the IncI2 and IncX4 plasmids carrying the mobile colistin resistance gene(mcr-1)by more than 160-fold in vitro in Escherichia coli,and more than two-fold(IncI2 plasmid)in vivo in a mouse model.It also suppressed the transfer of the IncX3 plasmid carrying the carbapenem resistance gene bla_(NDM-5)by more than twofold in vitro.Detection of intracellular adenosine triphosphate(ATP)and proton motive force(PMF),in combination with transcriptomic and metabolomic analyses,revealed that DHA impaired the function of the electron transport chain(ETC)by inhibiting the tricarboxylic acid(TCA)cycle pathway,thereby disrupting PMF and limiting the availability of intracellular ATP for plasmid conjugative transfer.Furthermore,expression levels of genes related to conjugation and pilus generation were significantly down-regulated during DHA exposure,indicating that the transfer apparatus for conjugation may be inhibited.Our findings provide new insights into the control of antibiotic resistance and the potential use of DHA.
基金the National Key Research and Development Program of China(2018YFE0192600)the Shanghai Agriculture Applied Technology Development Program,China(T20200104)+1 种基金the Fundamental Research Funds for the Central Universities,China(2020JB05)the Agricultural Science and Technology Innovation Program of Chinese Academy of Agricultural Sciences(CAAS-ZDRW202203).
文摘An extensively drug-resistant(XDR)Escherichia coli strain 258E was isolated from an anal swab sample of a chicken farm of Anhui province in China.Genomic analyses indicated that the strain 258E harbors an incompatibility group N(IncN)plasmid pEC258-3,which co-produces bla_(CTX-M-3),bla_(KPC-2),bla_(TEM-1B),qnrS1,aac(6')-Ib-cr,dfrA14,arr-3,and aac(6')-Ib3.Multiple genome arrangement analyses indicated that pEC258-3 is highly homologous with pCRKP-1-KPC discovered in Klebsiella pneumoniae from a patient.Furthermore,conjugation experiments proved that plasmid pEC258-3 can be transferred horizontally and may pose a significant potential threat in animals,community and hospital settings.
基金Supported by the National Key Research and Development Plan of China(2019YFC1905902,2019YFC1905900)Key Research and Development Plan in Shandong Province(2020CXGC010603,2021ZDSYS10,2022CXGC020206)+2 种基金"Open Competition Mechanism"Project of Qilu University of Technology(Shandong Academy of Sciences)(2022JBZ01-06)Taishan Industry Leading Talent Program(tscy20180103)National Natural Science Foundation of China(31801527)。
文摘Each possible pair of residues inβ-1,4 glucanase for disulfide formation was assessed using online websites,and four pairs L28C-S256C,Q41C-P278C,S122C-N163C and A184C-A215C were selected.Accordingly,four recombinant plasmids pET28a(+)EccslH28,pET28a(+)EccslH41,pET28a(+)EccslH122 and pET28a(+)EccslH184 were prepared and transformed into E.coli to express the recombinant enzymes.Then analysis on enzymatic properties showed that T50 of the recombinant enzymes was increased from 10 min for EccslHt2 to 90 min for EccslH28 and 40 min for EccslH41 at 70℃,while their optimum pH value and pH stability were not affected,which proved that the introduction of disulfide bond improved the thermal stability ofβ-1,4 glucanase.
