Background:Bladder cancer is the tenth most common cancer worldwide.Considering its high prevalence(vulnerability to multiple recurrences and progression despite local therapy),which leads to a substantial health serv...Background:Bladder cancer is the tenth most common cancer worldwide.Considering its high prevalence(vulnerability to multiple recurrences and progression despite local therapy),which leads to a substantial health service burden,it becomes necessary to develop new strategies to increase the effectiveness of bladder tumor therapy.Natural compounds with antiproliferative effect on cancer cells could be a good choice for co-adjuvant chemotherapy.Microorganisms are one of the main sources for natural compounds.Pigments extracted from the cold-adapted microorganisms can contribute to the development of a broader range of applications in biotechnology.Violacein is a purple pigment commonly produced by many bacterial strains.We have previously shown that very low concentrations of violacein extracted from Janthinobacterium sp.produced an antiproliferative effect on HeLa cells.Objective:With the aim to determine if violacein has an antiproliferative activity on bladder cancer cells,as well as to test if it has synergistic effects on cisplatin treated cells in vitro,T24 and 253J cell lines(derived bladder cancer cells from carcinoma in situ and retroperitoneal metastasis,respectively)were exposed to different concentrations of violacein in the presence or absence of cisplatin.Methods:i)Resazurin assay and flow cytometry were performed in two bladder cancer-derived cell lines,namely T24 and 253J,to see if violacein affects cell viability and induce cell death.ii)To find out whether violacein sensitizes bladder cancer cells to cisplatin,the drug interaction among different doses of cisplatin and violacein was analyzed,as well their combination index was determined.iii)The effect of violacein to induce primary genetic damage was determined through the analysis of induced micronuclei frequency and𝛾H2AX foci,as well as performing the comet assay.Results:The half-maximal inhibitory concentration of violacein at 24 h for both cell lines were around 500 nM,and decreased below 400 nM in combination with 10μM of cisplatin,indicating antiproliferative and sensitizing effects of violacein to cisplatin in both cell lines tested.A clear cell cycle delay,as well as an increase in the percentage of cell death was observed by flow cytometry at 300 nM of violacein,either alone or in combination with cisplatin.On the other hand,the analysis of the micronucleus frequency did not evidence an increase in genetic damage.Moreover,in combined treatments with cisplatin there was a slight decrease on micronucleus induction.Besides,the induction of genetic damage was not observed through comet assay when cells were treated with violacein alone,however,when cells were treated with violacein in the presence of cisplatin(10μM).The production of genetic damage was diminished in T24 or 253J cells.By the same token,increase in the frequency of𝛾H2AX foci by violacein was not observed at any tested dose in both cell lines.Conclusion:It was shown that violacein has an in vitro antiproliferative effect in bladder cancer cell lines,sensitizing them to cisplatin.Interestingly,at doses tested,violacein did not induce genotoxicity and reduce the genotoxic effect produced by cisplatin.展开更多
A bacterium B2 isolated from the Tianshan glacier of Xinjiang could produce blue pigments.According to 16S rDNA analysis, this isolate belonged to Duganella Genus .Two compounds were separated and purified from the cu...A bacterium B2 isolated from the Tianshan glacier of Xinjiang could produce blue pigments.According to 16S rDNA analysis, this isolate belonged to Duganella Genus .Two compounds were separated and purified from the cultivated Duganella B2 , named Blue-Ⅰand Blue-Ⅱ, respectively.From the spectra data of UV, MS and NMR of the compounds, Blue-Ⅰwas confirmed to be deoxyviolacein and Blue-Ⅱ was violacein.Blue-Ⅰand Blue-Ⅱ had the respective molecular weights of 327.2 and 343.2,and showed the characteristic absorption peaks at the respective 560 and 572 nm within the visible light range in ethanol solution.These results will be useful for developing the bioprocess for producing bacterial violacein.展开更多
Chromobacterium violaceum is a gram-negative bacterium, which has been used widely in microbiology labs involved in quorum sensing(QS) research. Among the QS-regulated traits of this bacterium, violacein production ha...Chromobacterium violaceum is a gram-negative bacterium, which has been used widely in microbiology labs involved in quorum sensing(QS) research. Among the QS-regulated traits of this bacterium, violacein production has received the maximum attention. Violacein production in this organism, however is not under sole control of QS machinery, and other QSregulated traits of this bacterium also need to be investigated in better detail. Though not often involved in human infections, this bacterium is being viewed as an emerging pathogen. This review attempts to highlight the recent research advances on Chromobacterium violaceum, with respect to violacein biosynthesis, development of various applications of this bacterium and its bioactive metabolite violacein, and its pathogenicity.展开更多
Microorganisms respond to various adverse environmental conditions and regulate different physiological functions by secreting and sensing signal molecules through quorum sensing(QS)systems.Phyllosilicates and iron ox...Microorganisms respond to various adverse environmental conditions and regulate different physiological functions by secreting and sensing signal molecules through quorum sensing(QS)systems.Phyllosilicates and iron oxides present in soils and sediments may have substantial impact on bacterial activity and QS due to their unique reactivity and close association with microorganisms.This research explored the effect of goethite,montmorillonite and kaolinite(0.05–2gL^(–1))on the growth and QS of a bacterial model,Chromobacterium violaceum.The results showed that kaolinite and goethite caused cellular damage at low mineral concentrations.The capacity for violacein production and biofilm formation of C.violaceum were inhibited by the minerals in the order of kaolinite>goethite>montmorillonite.The possible underlying mechanisms for QS inhibition by different minerals were investigated.Specifically,kaolinite repressed QS function through downregulation the expression of signal molecules synthesis gene cviI.Goethite and montmorillonite interfered with QS by adsorption of extracellular signal molecules.This work provides a better understanding of the interactions between bacteria and minerals and proposed that the inhibition of QS system is an ignored mechanism for bacterial toxicity by phyllosilicates and iron oxides.展开更多
基金the National Agency for Re-search and Innovation(ANII-Uruguay).
文摘Background:Bladder cancer is the tenth most common cancer worldwide.Considering its high prevalence(vulnerability to multiple recurrences and progression despite local therapy),which leads to a substantial health service burden,it becomes necessary to develop new strategies to increase the effectiveness of bladder tumor therapy.Natural compounds with antiproliferative effect on cancer cells could be a good choice for co-adjuvant chemotherapy.Microorganisms are one of the main sources for natural compounds.Pigments extracted from the cold-adapted microorganisms can contribute to the development of a broader range of applications in biotechnology.Violacein is a purple pigment commonly produced by many bacterial strains.We have previously shown that very low concentrations of violacein extracted from Janthinobacterium sp.produced an antiproliferative effect on HeLa cells.Objective:With the aim to determine if violacein has an antiproliferative activity on bladder cancer cells,as well as to test if it has synergistic effects on cisplatin treated cells in vitro,T24 and 253J cell lines(derived bladder cancer cells from carcinoma in situ and retroperitoneal metastasis,respectively)were exposed to different concentrations of violacein in the presence or absence of cisplatin.Methods:i)Resazurin assay and flow cytometry were performed in two bladder cancer-derived cell lines,namely T24 and 253J,to see if violacein affects cell viability and induce cell death.ii)To find out whether violacein sensitizes bladder cancer cells to cisplatin,the drug interaction among different doses of cisplatin and violacein was analyzed,as well their combination index was determined.iii)The effect of violacein to induce primary genetic damage was determined through the analysis of induced micronuclei frequency and𝛾H2AX foci,as well as performing the comet assay.Results:The half-maximal inhibitory concentration of violacein at 24 h for both cell lines were around 500 nM,and decreased below 400 nM in combination with 10μM of cisplatin,indicating antiproliferative and sensitizing effects of violacein to cisplatin in both cell lines tested.A clear cell cycle delay,as well as an increase in the percentage of cell death was observed by flow cytometry at 300 nM of violacein,either alone or in combination with cisplatin.On the other hand,the analysis of the micronucleus frequency did not evidence an increase in genetic damage.Moreover,in combined treatments with cisplatin there was a slight decrease on micronucleus induction.Besides,the induction of genetic damage was not observed through comet assay when cells were treated with violacein alone,however,when cells were treated with violacein in the presence of cisplatin(10μM).The production of genetic damage was diminished in T24 or 253J cells.By the same token,increase in the frequency of𝛾H2AX foci by violacein was not observed at any tested dose in both cell lines.Conclusion:It was shown that violacein has an in vitro antiproliferative effect in bladder cancer cell lines,sensitizing them to cisplatin.Interestingly,at doses tested,violacein did not induce genotoxicity and reduce the genotoxic effect produced by cisplatin.
文摘A bacterium B2 isolated from the Tianshan glacier of Xinjiang could produce blue pigments.According to 16S rDNA analysis, this isolate belonged to Duganella Genus .Two compounds were separated and purified from the cultivated Duganella B2 , named Blue-Ⅰand Blue-Ⅱ, respectively.From the spectra data of UV, MS and NMR of the compounds, Blue-Ⅰwas confirmed to be deoxyviolacein and Blue-Ⅱ was violacein.Blue-Ⅰand Blue-Ⅱ had the respective molecular weights of 327.2 and 343.2,and showed the characteristic absorption peaks at the respective 560 and 572 nm within the visible light range in ethanol solution.These results will be useful for developing the bioprocess for producing bacterial violacein.
文摘Chromobacterium violaceum is a gram-negative bacterium, which has been used widely in microbiology labs involved in quorum sensing(QS) research. Among the QS-regulated traits of this bacterium, violacein production has received the maximum attention. Violacein production in this organism, however is not under sole control of QS machinery, and other QSregulated traits of this bacterium also need to be investigated in better detail. Though not often involved in human infections, this bacterium is being viewed as an emerging pathogen. This review attempts to highlight the recent research advances on Chromobacterium violaceum, with respect to violacein biosynthesis, development of various applications of this bacterium and its bioactive metabolite violacein, and its pathogenicity.
基金the National Natural Science Foundation of China(41877029,41961130383)Royal Society-Newton Advanced Fellowship(NAF\R1\191017)+1 种基金the National Key Research Program of China(2016YFD0800206)Wuhan Science and Technology Bureau(2019020701011469).
文摘Microorganisms respond to various adverse environmental conditions and regulate different physiological functions by secreting and sensing signal molecules through quorum sensing(QS)systems.Phyllosilicates and iron oxides present in soils and sediments may have substantial impact on bacterial activity and QS due to their unique reactivity and close association with microorganisms.This research explored the effect of goethite,montmorillonite and kaolinite(0.05–2gL^(–1))on the growth and QS of a bacterial model,Chromobacterium violaceum.The results showed that kaolinite and goethite caused cellular damage at low mineral concentrations.The capacity for violacein production and biofilm formation of C.violaceum were inhibited by the minerals in the order of kaolinite>goethite>montmorillonite.The possible underlying mechanisms for QS inhibition by different minerals were investigated.Specifically,kaolinite repressed QS function through downregulation the expression of signal molecules synthesis gene cviI.Goethite and montmorillonite interfered with QS by adsorption of extracellular signal molecules.This work provides a better understanding of the interactions between bacteria and minerals and proposed that the inhibition of QS system is an ignored mechanism for bacterial toxicity by phyllosilicates and iron oxides.
