The study of microbial hydrocarbons removal is of great importance for the development of future bioremediation strategies.In this study,we evaluated the removal of a gaseous mixture containing toluene,m-xylene,ethylb...The study of microbial hydrocarbons removal is of great importance for the development of future bioremediation strategies.In this study,we evaluated the removal of a gaseous mixture containing toluene,m-xylene,ethylbenzene,cyclohexane,butane,pentane,hexane and heptane in aerated stirred bioreactors inoculated with Rhodococcus erythropolis and operated under non-sterile conditions.For the real-time measurement of hydrocarbons,a novel systematic approachwas implemented using Selected-Ion Flow TubeMass Spectrometry(SIFTMS).The effect of the carbon source(~9.5 ppmv)on(i)the bioreactors’performance(BR1:dosed with only cyclohexane as a single hydrocarbon versus BR2:dosed with a mixture of the 8 hydrocarbons)and(ii)the evolution of microbial communities over time were investigated.The results showed that cyclohexane reached a maximum removal efficiency(RE)of 53%±4%in BR1.In BR2,almost complete removal of toluene,m-xylene and ethylbenzene,being the most water-soluble and easy-to-degrade carbon sources,was observed.REs below 32%were obtained for the remaining compounds.By exposing the microbial consortium to only the five most recalcitrant hydrocarbons,REs between 45%±5%and 98%±1%were reached.In addition,we observed that airborne microorganisms populated the bioreactors and that the type of carbon source influenced the microbial communities developed.The abundance of species belonging to the genus Rhodococcus was below 10%in all bioreactors at the end of the experiments.This work provides fundamental insights to understand the complex behavior of gaseous hydrocarbon mixtures in bioreactors,along with a systematic approach for the development of SIFT-MS methods.展开更多
BACKGROUND Kidney transplantation is the best option for patients with end-stage renal disease.However,the need for lifelong immunosuppression results in renal transplant recipients being susceptible to various infect...BACKGROUND Kidney transplantation is the best option for patients with end-stage renal disease.However,the need for lifelong immunosuppression results in renal transplant recipients being susceptible to various infections.Rhodococcus equi(R.equi)is a rare opportunistic pathogen in humans,and there are limited reports of infection with R.equi in post-renal transplant recipients and no uniform standard of treat-ment.This article reports on the diagnosis and treatment of a renal transplant recipient infected with R.equi 21 mo postoperatively and summarizes the charac-teristics of infection with R.equi after renal transplantation,along with a detailed review of the literature.Here,we present the case of a 25-year-old man who was infected with R.equi 21 mo after renal transplantation.Although the clinical features at the time of presentation were not specific,chest computed tomography(CT)showed a large volume of pus in the right thoracic cavity and right middle lung atelectasis,and fiberoptic bronchoscopy showed an endobronchial mass in the right middle and lower lobe orifices.Bacterial culture and metagenomic next-generation sequen-cing sequencing of the pus were suggestive of R.equi infection.The immunosup-pressive drugs were immediately suspended and intravenous vancomycin and azithromycin were administered,along with adequate drainage of the abscess.The endobronchial mass was then resected.After the patient’s clinical symptoms and chest CT presentation resolved,he was switched to intravenous ciprofloxacin and azithromycin,followed by oral ciprofloxacin and azithromycin.The patient was re-hospitalized 2 wk after discharge for recurrence of R.equi infection.He recovered after another round of adequate abscess drainage and intravenous ciprofloxacin and azithromycin.CONCLUSION Infection with R.equi in renal transplant recipients is rare and complex,and the clinical presentation lacks specificity.Elaborate antibiotic therapy is required,and adequate abscess drainage and surgical excision are necessary.Given the recurrent nature of R.equi,patients need to be followed-up closely.展开更多
Among 39 species of microbial strains,Rhodococcus sp.AS 4.1147 possessed the ability to selectively acetylate puerarin（1） at C-6 position of the glucosyl moiety.The structure of the acetylated product,6’’-O-acetyl...Among 39 species of microbial strains,Rhodococcus sp.AS 4.1147 possessed the ability to selectively acetylate puerarin（1） at C-6 position of the glucosyl moiety.The structure of the acetylated product,6’’-O-acetylpuerarin（2） was determined by the analysis of MS,NMR spectroscopic data.The isolated yield of 2 was 22.2%.展开更多
基金supported by Ghent University through a special research grant(No.BOFSTG2019005701)The assistance provided by Ann Dirckx in the microbiology lab was greatly appreciated.Allan A.Alvarado-Alvarado thanks the European Commission under the Erasmus+EMJMD Program for funding his research at Ghent University(No.2017-1957/001-001-EMJMD).
文摘The study of microbial hydrocarbons removal is of great importance for the development of future bioremediation strategies.In this study,we evaluated the removal of a gaseous mixture containing toluene,m-xylene,ethylbenzene,cyclohexane,butane,pentane,hexane and heptane in aerated stirred bioreactors inoculated with Rhodococcus erythropolis and operated under non-sterile conditions.For the real-time measurement of hydrocarbons,a novel systematic approachwas implemented using Selected-Ion Flow TubeMass Spectrometry(SIFTMS).The effect of the carbon source(~9.5 ppmv)on(i)the bioreactors’performance(BR1:dosed with only cyclohexane as a single hydrocarbon versus BR2:dosed with a mixture of the 8 hydrocarbons)and(ii)the evolution of microbial communities over time were investigated.The results showed that cyclohexane reached a maximum removal efficiency(RE)of 53%±4%in BR1.In BR2,almost complete removal of toluene,m-xylene and ethylbenzene,being the most water-soluble and easy-to-degrade carbon sources,was observed.REs below 32%were obtained for the remaining compounds.By exposing the microbial consortium to only the five most recalcitrant hydrocarbons,REs between 45%±5%and 98%±1%were reached.In addition,we observed that airborne microorganisms populated the bioreactors and that the type of carbon source influenced the microbial communities developed.The abundance of species belonging to the genus Rhodococcus was below 10%in all bioreactors at the end of the experiments.This work provides fundamental insights to understand the complex behavior of gaseous hydrocarbon mixtures in bioreactors,along with a systematic approach for the development of SIFT-MS methods.
基金Supported by Science and Technology Project of Guizhou Province,No.ZK[2023]380.
文摘BACKGROUND Kidney transplantation is the best option for patients with end-stage renal disease.However,the need for lifelong immunosuppression results in renal transplant recipients being susceptible to various infections.Rhodococcus equi(R.equi)is a rare opportunistic pathogen in humans,and there are limited reports of infection with R.equi in post-renal transplant recipients and no uniform standard of treat-ment.This article reports on the diagnosis and treatment of a renal transplant recipient infected with R.equi 21 mo postoperatively and summarizes the charac-teristics of infection with R.equi after renal transplantation,along with a detailed review of the literature.Here,we present the case of a 25-year-old man who was infected with R.equi 21 mo after renal transplantation.Although the clinical features at the time of presentation were not specific,chest computed tomography(CT)showed a large volume of pus in the right thoracic cavity and right middle lung atelectasis,and fiberoptic bronchoscopy showed an endobronchial mass in the right middle and lower lobe orifices.Bacterial culture and metagenomic next-generation sequen-cing sequencing of the pus were suggestive of R.equi infection.The immunosup-pressive drugs were immediately suspended and intravenous vancomycin and azithromycin were administered,along with adequate drainage of the abscess.The endobronchial mass was then resected.After the patient’s clinical symptoms and chest CT presentation resolved,he was switched to intravenous ciprofloxacin and azithromycin,followed by oral ciprofloxacin and azithromycin.The patient was re-hospitalized 2 wk after discharge for recurrence of R.equi infection.He recovered after another round of adequate abscess drainage and intravenous ciprofloxacin and azithromycin.CONCLUSION Infection with R.equi in renal transplant recipients is rare and complex,and the clinical presentation lacks specificity.Elaborate antibiotic therapy is required,and adequate abscess drainage and surgical excision are necessary.Given the recurrent nature of R.equi,patients need to be followed-up closely.
基金The Science & Technology Project of Guangdong Province (Grant No. 2011A080403020)the Program for New Century Excellent Talents in University (Grant No. NCET-06-0155)
文摘Among 39 species of microbial strains,Rhodococcus sp.AS 4.1147 possessed the ability to selectively acetylate puerarin（1） at C-6 position of the glucosyl moiety.The structure of the acetylated product,6’’-O-acetylpuerarin（2） was determined by the analysis of MS,NMR spectroscopic data.The isolated yield of 2 was 22.2%.
