Background:The effects of perilla leaf oil on the antibacterial activity,biofilm formation,and group sensing related genes of Salmonella dysentery in chickens were investigated.Perilla leaf oil was compared with the a...Background:The effects of perilla leaf oil on the antibacterial activity,biofilm formation,and group sensing related genes of Salmonella dysentery in chickens were investigated.Perilla leaf oil was compared with the antibiotic gentamycin hydrochloride,which is commonly used in the chicken industry,to provide experimental data and theoretical basis for the further development of perilla leaf oil as a new type of antimicrobial drug to replace feed antibiotics.Methods:The minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of perilla leaf oil and the antibiotic aureomycin hydrochloride against three clinical isolates of Salmonella typhimurium were determined by microbial broth dilution,and SP-2 was screened out from them.The dynamic bactericidal effect of perilla leaf oil and aureomycin hydrochloride on SP-2 was obtained by the viable bacteria counting method and the time-bactericidal curves.The successful establishment of biological periplasm and the corresponding times of its various growth stages of adhesion,aggregation,and maturation were determined by cell counting kit-8(CCK-8)reagent and scanning electron microscopy(SEM).The effects of different concentrations of perilla leaf oil on biofilm at different stages were investigated by CCK-8 method and semi-quantitative adhesion method of crystalline violet,and the changes in microstructure and morphology of biofilm at different stages under the effect of drugs were observed by SEM.The effect of perilla leaf oil on the expression of genes related to the formation of the population sensing system(luxS and sdiA)in the test strain SP-2 was detected by qRT-PCR.Results:The MIC value of perilla leaf oil on SP-2 was 2.000±0.000 mg/mL.Perilla leaf oil and gentamycin hydrochloride could effectively inhibit and kill SP-2 in a planktonic state,and delay the entry of bacteria into the logarithmic growth period.6 h,24 h,and 48 h were chosen as the time points for the drug intervention in the initial adhesion,aggregation,and maturation stages of the biofilm of SP-2.1 mg/mL perilla leaf oil was significantly better than the same concentration of gentamycin hydrochloride in removing the total amount of biofilm of SP-2 at all growth stages(P<0.05).The inhibitory effect of 4 mg/mL perilla leaf oil on the bacterial metabolic activity in SP-2 biofilm at the mature stage was significantly better than that of the same concentration of gentamycin hydrochloride(P<0.01).For SP-2 biofilm at all stages of growth,different concentrations of perilla leaf oil significantly down-regulated the expression of luxS and sdiA genes(P<0.05),interfered with the group sensing system of SP-2,and inhibited the formation of its biofilm.Conclusion:The perilla leaf oil has a good antibacterial activity and biofilm inhibition effect on SP-2 of S.Pullorum at different growth stages.展开更多
Background:To investigate the effect of flavaspidic acid BB(BB)on biofilms and quorum sensing-related genes of drug-resistant Staphylococcus epidermidis(SE)and to provide a theoretical basis for the development of BB ...Background:To investigate the effect of flavaspidic acid BB(BB)on biofilms and quorum sensing-related genes of drug-resistant Staphylococcus epidermidis(SE)and to provide a theoretical basis for the development of BB as a new type of quorum sensing inhibitor.Methods:The microdilution method was applied to screen 15 clinical isolates of S.epidermidis for drug-resistant S.epidermidis to be used as the test strain.The effects of BB on the biofilms of drug-resistant S.epidermidis at different growth stages were studied using the cell counting kit-8 assay and scanning electron microscopy.The gene expression of sigB,sarA,and luxS,regulators involved in quorum sensing of biofilm formation,was measured by PCR.Results:The minimum inhibitory concentrations of BB against 15 clinical strains of S.epidermidis ranged 11.67-66.67μg/mL.BB significantly inhibited biofilm formation by drug-resistant SE06 in the aggregation and maturation stages,with an activity superior to those of mupirocin and fusidic acid(P<0.05).At 40μg/mL,BB reduced the secretion of extracellular polymers and promoted the disruption of biofilm structure.At 80μg/mL,BB specifically interfered with the quorum sensing system of drug-resistant SE06 by downregulating sarA and luxS,thereby inhibiting this microbe’s biofilm formation.Conclusion:BB exhibited strong inhibitory activity against SE06 by suppressing biofilm formation and downregulating quorum sensing-related genes and was identified as a new potential quorum sensing inhibitor against S.epidermidis.展开更多
Background:Based on modern pharmacological studies,Terminalia chebula Retz.exhibits antimicrobial activity against a variety of bacteria.Previously,we found Terminalia chebula Retz.exhibited excellent antibacterial ac...Background:Based on modern pharmacological studies,Terminalia chebula Retz.exhibits antimicrobial activity against a variety of bacteria.Previously,we found Terminalia chebula Retz.exhibited excellent antibacterial activity against Malassezia restricta.Methods:We determined the minimal inhibitory concentration(MIC)and minimum bactericidal concentration of Terminalia chebula Retz.extraction with water(TRW)against Staphylococcus epidermidis(including Staphylococcus epidermidis 1-15)using the microdilution method.Staphylococcus epidermidis 1(SE11),which was the most sensitive to TRW,was selected as the test bacterium for subsequent experiments.The time-kill curve of TRW on SE11 was generated using the viable count method.Further,an in vitro biofilm model of SE11 was constructed using the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-((phenylamino)carbonyl)-2H-tetrazolium hydroxide test,semi-quantitative crystal violet experiment,and scanning electron microscopy.The effects of TRW on the total amount of biofilm formation,the number of viable biofilm bacteria,and biofilm microstructure of SE11 were also determined using a semi-quantitative crystal violet experiment,viable count method,and scanning electron microscopy.Finally,the electrical conductivity and soluble protein content of the SE11 suspensions were determined.Results:The average MIC of TRW against SE11 was 0.75±1.09 mg/mL.TRW(1/2MIC and 2MIC)and zinc pyrithione(1/2MIC and 2MIC)had no significant effect on total biofilm inhibition in the adhesion stage(P>0.05)and the aggregation stage(P>0.05).Further,TRW(1/2MIC and MIC)and zinc pyrithione(1/2MIC and MIC)had no significant effect on viable biofilm bacteria in the adhesion stage(P>0.05)and aggregation stage(P>0.05).TRW destroyed the integrity of the SE11 cell membrane,resulting in leakage of intracellular substances.Conclusion:TRW inhibits SE11 biofilm formation and is similar to zinc pyrithione in the adhesion and aggregation stages,which provides a theoretical basis for its application in the field of antimicrobial additives.展开更多
Objectives Aspidin BB, a typical phloroglucinol derivative from Dryopteris fragrans, possesses significant antifungal property. This study aimed to investigate potential mechanism of antifungal activity of Aspidin BB ...Objectives Aspidin BB, a typical phloroglucinol derivative from Dryopteris fragrans, possesses significant antifungal property. This study aimed to investigate potential mechanism of antifungal activity of Aspidin BB against Trichophyton rubrum which is the most common pathogens responsible for chronic dermatophytosis. Methods The minimum inhibitory concentration （MIC） ofAspidin BB against strains was determined by broth microdilution. The effects of Aspidin BB on ergosterol biosynthesis were investigated by content determination based on UPLC method. Besides, the effects of drugs on squalene epoxidase （SE） in T. rubrum cell membrane were analyzed. Results MIC value of Aspidin BB against T. rubrum was 25.0 IJg/mL. Aspidin BB reduced ergosterol content significantly, but no notable effect on squalene epoxidase activity. Conclusion The results suggested that Aspidin BB inhibited ergosterol biosynthesis. However, it was not squalene epoxidase but other components may sever as possible targets in ergosterol biosynthesis pathway.展开更多
文摘Background:The effects of perilla leaf oil on the antibacterial activity,biofilm formation,and group sensing related genes of Salmonella dysentery in chickens were investigated.Perilla leaf oil was compared with the antibiotic gentamycin hydrochloride,which is commonly used in the chicken industry,to provide experimental data and theoretical basis for the further development of perilla leaf oil as a new type of antimicrobial drug to replace feed antibiotics.Methods:The minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of perilla leaf oil and the antibiotic aureomycin hydrochloride against three clinical isolates of Salmonella typhimurium were determined by microbial broth dilution,and SP-2 was screened out from them.The dynamic bactericidal effect of perilla leaf oil and aureomycin hydrochloride on SP-2 was obtained by the viable bacteria counting method and the time-bactericidal curves.The successful establishment of biological periplasm and the corresponding times of its various growth stages of adhesion,aggregation,and maturation were determined by cell counting kit-8(CCK-8)reagent and scanning electron microscopy(SEM).The effects of different concentrations of perilla leaf oil on biofilm at different stages were investigated by CCK-8 method and semi-quantitative adhesion method of crystalline violet,and the changes in microstructure and morphology of biofilm at different stages under the effect of drugs were observed by SEM.The effect of perilla leaf oil on the expression of genes related to the formation of the population sensing system(luxS and sdiA)in the test strain SP-2 was detected by qRT-PCR.Results:The MIC value of perilla leaf oil on SP-2 was 2.000±0.000 mg/mL.Perilla leaf oil and gentamycin hydrochloride could effectively inhibit and kill SP-2 in a planktonic state,and delay the entry of bacteria into the logarithmic growth period.6 h,24 h,and 48 h were chosen as the time points for the drug intervention in the initial adhesion,aggregation,and maturation stages of the biofilm of SP-2.1 mg/mL perilla leaf oil was significantly better than the same concentration of gentamycin hydrochloride in removing the total amount of biofilm of SP-2 at all growth stages(P<0.05).The inhibitory effect of 4 mg/mL perilla leaf oil on the bacterial metabolic activity in SP-2 biofilm at the mature stage was significantly better than that of the same concentration of gentamycin hydrochloride(P<0.01).For SP-2 biofilm at all stages of growth,different concentrations of perilla leaf oil significantly down-regulated the expression of luxS and sdiA genes(P<0.05),interfered with the group sensing system of SP-2,and inhibited the formation of its biofilm.Conclusion:The perilla leaf oil has a good antibacterial activity and biofilm inhibition effect on SP-2 of S.Pullorum at different growth stages.
文摘Background:To investigate the effect of flavaspidic acid BB(BB)on biofilms and quorum sensing-related genes of drug-resistant Staphylococcus epidermidis(SE)and to provide a theoretical basis for the development of BB as a new type of quorum sensing inhibitor.Methods:The microdilution method was applied to screen 15 clinical isolates of S.epidermidis for drug-resistant S.epidermidis to be used as the test strain.The effects of BB on the biofilms of drug-resistant S.epidermidis at different growth stages were studied using the cell counting kit-8 assay and scanning electron microscopy.The gene expression of sigB,sarA,and luxS,regulators involved in quorum sensing of biofilm formation,was measured by PCR.Results:The minimum inhibitory concentrations of BB against 15 clinical strains of S.epidermidis ranged 11.67-66.67μg/mL.BB significantly inhibited biofilm formation by drug-resistant SE06 in the aggregation and maturation stages,with an activity superior to those of mupirocin and fusidic acid(P<0.05).At 40μg/mL,BB reduced the secretion of extracellular polymers and promoted the disruption of biofilm structure.At 80μg/mL,BB specifically interfered with the quorum sensing system of drug-resistant SE06 by downregulating sarA and luxS,thereby inhibiting this microbe’s biofilm formation.Conclusion:BB exhibited strong inhibitory activity against SE06 by suppressing biofilm formation and downregulating quorum sensing-related genes and was identified as a new potential quorum sensing inhibitor against S.epidermidis.
文摘Background:Based on modern pharmacological studies,Terminalia chebula Retz.exhibits antimicrobial activity against a variety of bacteria.Previously,we found Terminalia chebula Retz.exhibited excellent antibacterial activity against Malassezia restricta.Methods:We determined the minimal inhibitory concentration(MIC)and minimum bactericidal concentration of Terminalia chebula Retz.extraction with water(TRW)against Staphylococcus epidermidis(including Staphylococcus epidermidis 1-15)using the microdilution method.Staphylococcus epidermidis 1(SE11),which was the most sensitive to TRW,was selected as the test bacterium for subsequent experiments.The time-kill curve of TRW on SE11 was generated using the viable count method.Further,an in vitro biofilm model of SE11 was constructed using the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-((phenylamino)carbonyl)-2H-tetrazolium hydroxide test,semi-quantitative crystal violet experiment,and scanning electron microscopy.The effects of TRW on the total amount of biofilm formation,the number of viable biofilm bacteria,and biofilm microstructure of SE11 were also determined using a semi-quantitative crystal violet experiment,viable count method,and scanning electron microscopy.Finally,the electrical conductivity and soluble protein content of the SE11 suspensions were determined.Results:The average MIC of TRW against SE11 was 0.75±1.09 mg/mL.TRW(1/2MIC and 2MIC)and zinc pyrithione(1/2MIC and 2MIC)had no significant effect on total biofilm inhibition in the adhesion stage(P>0.05)and the aggregation stage(P>0.05).Further,TRW(1/2MIC and MIC)and zinc pyrithione(1/2MIC and MIC)had no significant effect on viable biofilm bacteria in the adhesion stage(P>0.05)and aggregation stage(P>0.05).TRW destroyed the integrity of the SE11 cell membrane,resulting in leakage of intracellular substances.Conclusion:TRW inhibits SE11 biofilm formation and is similar to zinc pyrithione in the adhesion and aggregation stages,which provides a theoretical basis for its application in the field of antimicrobial additives.
基金Application-oriented Research Project of Guangdong Provincial Department of Science and Technology(2015B020234009)Traditional Chinese Medicine Industry Research Project of State Administration of Traditional Chinese Medicine of People’s Republic of China(201507004)
文摘Objectives Aspidin BB, a typical phloroglucinol derivative from Dryopteris fragrans, possesses significant antifungal property. This study aimed to investigate potential mechanism of antifungal activity of Aspidin BB against Trichophyton rubrum which is the most common pathogens responsible for chronic dermatophytosis. Methods The minimum inhibitory concentration （MIC） ofAspidin BB against strains was determined by broth microdilution. The effects of Aspidin BB on ergosterol biosynthesis were investigated by content determination based on UPLC method. Besides, the effects of drugs on squalene epoxidase （SE） in T. rubrum cell membrane were analyzed. Results MIC value of Aspidin BB against T. rubrum was 25.0 IJg/mL. Aspidin BB reduced ergosterol content significantly, but no notable effect on squalene epoxidase activity. Conclusion The results suggested that Aspidin BB inhibited ergosterol biosynthesis. However, it was not squalene epoxidase but other components may sever as possible targets in ergosterol biosynthesis pathway.
