Staphylococcus aureus is a common cause of diverse infections,ranging from superficial to invasive,affecting both humans and animals.The widespread use of antibiotics in clinical treatments has led to the emergence of...Staphylococcus aureus is a common cause of diverse infections,ranging from superficial to invasive,affecting both humans and animals.The widespread use of antibiotics in clinical treatments has led to the emergence of antibiotic-resistant strains and small colony variants.This surge presents a significant challenge in eliminating infections and undermines the efficacy of available treatments.The bacterial Save Our Souls(Sos)response,triggered by genotoxic stressors,encompasses host immune defenses and antibiotics,playing a crucial role in bacterial survival,invasiveness,virulence,and drug resistance.Accumulating evidence underscores the pivotal role of the Sos response system in the pathogenicity of S.aureus.Inhibiting this system offers a promising approach for effective bactericidal treatments and curbing the evolution of antimicrobial re-sistance.Here,we provide a comprehensive review of the activation,impact,and key proteins associated with the Sos response in S.aureus.Additionally,perspectives on therapeutic strategies targeting the Sos response for S.aureus,both individually and in combination with traditional antibiotics are proposed.展开更多
Bacteria can evolve rapidly by acquiring new traits such as virulence,metabolic properties,and most importantly,antimicrobial resistance,through horizontal gene transfer(HGT).Multidrug resistance in bacteria,especiall...Bacteria can evolve rapidly by acquiring new traits such as virulence,metabolic properties,and most importantly,antimicrobial resistance,through horizontal gene transfer(HGT).Multidrug resistance in bacteria,especially in Gram-negative organisms,has become a global public health threat often through the spread of mobile genetic elements.Conjugation represents a major form of HGT and involves the transfer of DNA from a donor bacterium to a recipient by direct contact.Conjugative plasmids,a major vehicle for the dissemination of antimicrobial resistance,are selfish elements capable of mediating their own transmission through conjugation.To spread to and survive in a new bacterial host,conjugative plasmids have evolved mechanisms to circumvent both host defense systems and compete with co-resident plasmids.Such mechanisms have mostly been studied in model plasmids such as the F plasmid,rather than in conjugative plasmids that confer antimicrobial resistance(AMR)in important human pathogens.A better understanding of these mechanisms is crucial for predicting the flow of antimicrobial resistance-conferring conjugative plasmids among bacterial populations and guiding the rational design of strategies to halt the spread of antimicrobial resistance.Here,we review mechanisms employed by conjugative plasmids that promote their transmission and establishment in Gram-negative bacteria,by following the life cycle of conjugative plasmids.展开更多
The adaptive survival mechanisms of bacterial pathogens under host-induced stress are crucial for understanding pathogenesis.Recently,Uppalapati et al.revealed a unique dual function of the Gifsy-1 prophage terminase ...The adaptive survival mechanisms of bacterial pathogens under host-induced stress are crucial for understanding pathogenesis.Recently,Uppalapati et al.revealed a unique dual function of the Gifsy-1 prophage terminase in Salmonella enterica:it acts as a transfer ribonuclease(tRNase)under oxidative stress.The Gifsy-1 prophage terminase targets and fragments tRNALeu to halt translation and temporarily impairs bacterial growth when exposed to high levels of ROS generated by the host immune cells.This response not only preserves genomic integrity by facilitating DNA repair but also inhibits prophage mobilization,thereby aiding in bacterial survival within vertebrate hosts.This study highlights a novel intersection between phage biology and bacterial adaptive strategies.展开更多
An E. coli SOS-EGFP biosensor which expresses enhanced green fluorescent protein as a reporter protein under the control of recA gene promoter in SOS response was constructed for detection of DNA damage and evaluation...An E. coli SOS-EGFP biosensor which expresses enhanced green fluorescent protein as a reporter protein under the control of recA gene promoter in SOS response was constructed for detection of DNA damage and evaluation of DNA damaging chemicals. The chemicals that may cause substantial DNA damage will trigger SOS response in the constructed bacterial biosensor, and then the reporter egfp gene under the control of recA promoter is stimulated to express as a fluorescent protein, allowing fast and sensitive fluorescence detection. Interestingly, this biosensor can be simultaneously applied for evaluation of genotoxicity and cytotoxicity. The SOS-EGFP bacterial biosensor provides a sensitive, specific and simple method for detecting known and potential DNA damaging chemicals.展开更多
The dissimilatory reduction of Fe(III)oxides driven by Fe(III)-reducing bacteria(FRB)is an important biogeo-chemical process that influences not only iron cycling but also the biogeochemical cycles of carbon,trace met...The dissimilatory reduction of Fe(III)oxides driven by Fe(III)-reducing bacteria(FRB)is an important biogeo-chemical process that influences not only iron cycling but also the biogeochemical cycles of carbon,trace metals,nutrients and contaminants.Phages have central roles in modulating the population and activity of FRB,but the mechanism for phage-involved Fe(III)oxide reduction is still unclear.This work used a common FRB,Geobacter soli,to explore the roles and underlying mechanisms of FRB-harboring prophages in the dissimilatory reduction of Fe(III)oxides.Bioinformatic analysis predicted 185 phage-related genes in the G.soli genome,comprising functional prophages that were verified to be induced to form tailed phage particles.Ferrihydrite reduction was facilitated as prophage induction was stimulated and declined as prophage induction was inhibited,which indi-cated a positive role of G.soli-harboring prophages in Fe(III)oxide reduction.A comparison of gene expression and released phage particles in the cells grown with Fe(III)-citrate and ferrihydrite suggested that microbial fer-rihydrite reduction would activate the SOS response and consequently induce the prophages to enter lytic cycles.The prophage-mediated lysis of the subpopulation resulted in an increased release of extracellular DNA and mem-brane vesicles that were conducive to Fe(III)oxide reduction,which might explain the positive role of prophages in ferrihydrite reduction.In summary,our results revealed the functional roles and underlying mechanisms of FRB-associated prophages in facilitating the dissimilatory reduction of Fe(III)oxides,which will advance our understanding of iron cycling in natural ecosystems.展开更多
基金This work was supported by the National Natural Science Foundation of China(32270043 and 32100017)the Natural Science Foundation of Zhejiang Province(LQ22C050002)+2 种基金the State Key Laboratory Foundation for Diagnosis and Treatment of Infectious Diseases to KC(zz202309)the Hangzhou Youth Innovation Team Project(TD2023020)the Scientific Research Foundation for Scholars of HZNU(4125C50221204040).
文摘Staphylococcus aureus is a common cause of diverse infections,ranging from superficial to invasive,affecting both humans and animals.The widespread use of antibiotics in clinical treatments has led to the emergence of antibiotic-resistant strains and small colony variants.This surge presents a significant challenge in eliminating infections and undermines the efficacy of available treatments.The bacterial Save Our Souls(Sos)response,triggered by genotoxic stressors,encompasses host immune defenses and antibiotics,playing a crucial role in bacterial survival,invasiveness,virulence,and drug resistance.Accumulating evidence underscores the pivotal role of the Sos response system in the pathogenicity of S.aureus.Inhibiting this system offers a promising approach for effective bactericidal treatments and curbing the evolution of antimicrobial re-sistance.Here,we provide a comprehensive review of the activation,impact,and key proteins associated with the Sos response in S.aureus.Additionally,perspectives on therapeutic strategies targeting the Sos response for S.aureus,both individually and in combination with traditional antibiotics are proposed.
基金the Wellcome Trust,BBSRC,and the National Natural Science Foundation of China(81802065,102908/Z/13/Z).
文摘Bacteria can evolve rapidly by acquiring new traits such as virulence,metabolic properties,and most importantly,antimicrobial resistance,through horizontal gene transfer(HGT).Multidrug resistance in bacteria,especially in Gram-negative organisms,has become a global public health threat often through the spread of mobile genetic elements.Conjugation represents a major form of HGT and involves the transfer of DNA from a donor bacterium to a recipient by direct contact.Conjugative plasmids,a major vehicle for the dissemination of antimicrobial resistance,are selfish elements capable of mediating their own transmission through conjugation.To spread to and survive in a new bacterial host,conjugative plasmids have evolved mechanisms to circumvent both host defense systems and compete with co-resident plasmids.Such mechanisms have mostly been studied in model plasmids such as the F plasmid,rather than in conjugative plasmids that confer antimicrobial resistance(AMR)in important human pathogens.A better understanding of these mechanisms is crucial for predicting the flow of antimicrobial resistance-conferring conjugative plasmids among bacterial populations and guiding the rational design of strategies to halt the spread of antimicrobial resistance.Here,we review mechanisms employed by conjugative plasmids that promote their transmission and establishment in Gram-negative bacteria,by following the life cycle of conjugative plasmids.
文摘The adaptive survival mechanisms of bacterial pathogens under host-induced stress are crucial for understanding pathogenesis.Recently,Uppalapati et al.revealed a unique dual function of the Gifsy-1 prophage terminase in Salmonella enterica:it acts as a transfer ribonuclease(tRNase)under oxidative stress.The Gifsy-1 prophage terminase targets and fragments tRNALeu to halt translation and temporarily impairs bacterial growth when exposed to high levels of ROS generated by the host immune cells.This response not only preserves genomic integrity by facilitating DNA repair but also inhibits prophage mobilization,thereby aiding in bacterial survival within vertebrate hosts.This study highlights a novel intersection between phage biology and bacterial adaptive strategies.
基金supported by the National Natural Science Foundation of China (No. 20707034, 20877091,20890112, 20921063)the National Basic Research Program (973) of China (No. 09CB421605,2010CB933500, 2011CB936001)
文摘An E. coli SOS-EGFP biosensor which expresses enhanced green fluorescent protein as a reporter protein under the control of recA gene promoter in SOS response was constructed for detection of DNA damage and evaluation of DNA damaging chemicals. The chemicals that may cause substantial DNA damage will trigger SOS response in the constructed bacterial biosensor, and then the reporter egfp gene under the control of recA promoter is stimulated to express as a fluorescent protein, allowing fast and sensitive fluorescence detection. Interestingly, this biosensor can be simultaneously applied for evaluation of genotoxicity and cytotoxicity. The SOS-EGFP bacterial biosensor provides a sensitive, specific and simple method for detecting known and potential DNA damaging chemicals.
基金supported by the National Natural Science Foundation of China(42077211)the Natural Science Foundation of Guangdong Province(2021A1515012570,2022A1515011734).
文摘The dissimilatory reduction of Fe(III)oxides driven by Fe(III)-reducing bacteria(FRB)is an important biogeo-chemical process that influences not only iron cycling but also the biogeochemical cycles of carbon,trace metals,nutrients and contaminants.Phages have central roles in modulating the population and activity of FRB,but the mechanism for phage-involved Fe(III)oxide reduction is still unclear.This work used a common FRB,Geobacter soli,to explore the roles and underlying mechanisms of FRB-harboring prophages in the dissimilatory reduction of Fe(III)oxides.Bioinformatic analysis predicted 185 phage-related genes in the G.soli genome,comprising functional prophages that were verified to be induced to form tailed phage particles.Ferrihydrite reduction was facilitated as prophage induction was stimulated and declined as prophage induction was inhibited,which indi-cated a positive role of G.soli-harboring prophages in Fe(III)oxide reduction.A comparison of gene expression and released phage particles in the cells grown with Fe(III)-citrate and ferrihydrite suggested that microbial fer-rihydrite reduction would activate the SOS response and consequently induce the prophages to enter lytic cycles.The prophage-mediated lysis of the subpopulation resulted in an increased release of extracellular DNA and mem-brane vesicles that were conducive to Fe(III)oxide reduction,which might explain the positive role of prophages in ferrihydrite reduction.In summary,our results revealed the functional roles and underlying mechanisms of FRB-associated prophages in facilitating the dissimilatory reduction of Fe(III)oxides,which will advance our understanding of iron cycling in natural ecosystems.
