Drinking water may be a risk factor for human infections if the water supply is contaminated with biofilm producing bacteria such as Legionella pneumophilae or Pseudomonas aeruginosa. Several situations have to be con...Drinking water may be a risk factor for human infections if the water supply is contaminated with biofilm producing bacteria such as Legionella pneumophilae or Pseudomonas aeruginosa. Several situations have to be considered when water supply to new buildings is planned. The aim of this paper is to review situations that have to be considered in new buildings and give an example on a new water supply contaminated with biofilm producing water bacteria and the precautions introduced to eliminate the contamination. When new buildings are planned it should be considered where to get the water and what is the microbiological quality of the water. If the water is contaminated there will be troubles from the beginning. The material for the pipes should be considered as biofilm which is produced in greater amounts and faster in PEG pipes than in stainless steel pipes. The choice of material depends on the expected lifetime of the building, the dimensions of the pipes, and the choice of forceps, how often the taps are used and thereby the flow in the system. The higher flow the less and slower biofilm formation. It is important to reduce the number of taps to a minimum to ovoid ＂dead ends＂ if they are not or only seldom used. Alternatively all taps could be opened automatically regularly. It is important to establish precautions to ovoid contamination of the water system in the period from when it is established until the building is taken in use. The period can be several months during which the system can act as a ＂dead end＂ if no precautions, such as regularly opening of all taps, are taken. The microbiological quality of the water in the system should be controlled before the building is taken in use. In a new building, where the water supply and the water in the building was not controlled before the building was taken in use, extremely high total and Legionella germ counts were found. The water was disinfected with low concentrations of chloride with very little effect. After disinfection with high concentrations of chloride for few hours and placing a sterile filter at the water entrance both the total and Legionella germ count decreased to an acceptable level.展开更多
Polycyclic aromatic hydrocarbons （PAHs） in soil retain for a quite long period due to their hydrophobicity and aggregation properties. Biofilm-forming marine bacterial consortium （named as NCPR）, composed of Steno...Polycyclic aromatic hydrocarbons （PAHs） in soil retain for a quite long period due to their hydrophobicity and aggregation properties. Biofilm-forming marine bacterial consortium （named as NCPR）, composed of Stenotrophomonas acidaminiphila NCW702, Alcaligenes faecalis NCW402, Pseudomonas mendocina NR802, Pseudornonas aeruginosa N6P6, and Pseudomonas pseudoalcaligenes NP103, was used for the bioremediation of PAHs in a soil microcosm. Phenanthrene and pyrene were used as reference PAHs. Parameters that can affect PAH degradation, such as chemotaxis, solubility of PAHs in extracellular polymeric substances （EPS）, and catechol 2,3-dioxygenase （C230） activity, were evaluated. P. aeruginosa N6P6 and P. pseudoalcaligenes NP103 showed chemotactic movement towards both the reference PAHs. The solubility of both the PAHs was increased with an increase in EPS concentration （extracted from all the 5 selected isolates）. Significantly （P 〈 0.001） high phenanthrene （70.29%） and pyrene （55.54%） degradation was observed in the bioaugmented soil microcosm. The C230 enzyme activity was significantly （P 〈 0.05） higher in the bioaugmented soil mi- crocosm with phenanthrene added at 173.26 ± 2.06 nmol rain-1 mg-1 protein than with pyrene added at 61.80 ± 2.20 nmol min-1 mg-1 protein. The C230 activity and gas chromatography-mass spectrometer analyses indicated catechol pathway of phenanthrene metabolism. However, the metabolites obtained from the soil microcosm added with pyrene revealed both the catechol and phthalate pathways for pyrene degradation.展开更多
During infections,bacteria stimulate host cells to produce and release histamine,which is a key mediator of vital cellular processes in animals.However,the mechanisms underlying the bacterial cell’s ability to sense ...During infections,bacteria stimulate host cells to produce and release histamine,which is a key mediator of vital cellular processes in animals.However,the mechanisms underlying the bacterial cell’s ability to sense and respond to histamine are poorly understood.Herein,we show that HinK,a Lys R-type transcriptional regulator,is required to evoke responses to histamine in Pseudomonas aeruginosa,an important human pathogen.HinK directly binds to and activates the promoter of genes involved in histamine uptake and metabolism,iron acquisition,and Pseudomonas quinolone signal(PQS)biosynthesis.The transcriptional regulatory activity of HinK is induced when histamine is present,and it occurs when HinK binds with imidazole-4-acetic acid(Im AA),a histamine metabolite whose production in P.aeruginosa depends on the HinK-activated histamine uptake and utilization operon hin DAC-pa0222.Importantly,the inactivation of HinK inhibits diverse pathogenic phenotypes of P.aeruginosa.These results suggest that histamine acts as an interkingdom signal and provide insights into the mechanism used by pathogenic bacteria to exploit host regulatory signals to promote virulence.展开更多
文摘Drinking water may be a risk factor for human infections if the water supply is contaminated with biofilm producing bacteria such as Legionella pneumophilae or Pseudomonas aeruginosa. Several situations have to be considered when water supply to new buildings is planned. The aim of this paper is to review situations that have to be considered in new buildings and give an example on a new water supply contaminated with biofilm producing water bacteria and the precautions introduced to eliminate the contamination. When new buildings are planned it should be considered where to get the water and what is the microbiological quality of the water. If the water is contaminated there will be troubles from the beginning. The material for the pipes should be considered as biofilm which is produced in greater amounts and faster in PEG pipes than in stainless steel pipes. The choice of material depends on the expected lifetime of the building, the dimensions of the pipes, and the choice of forceps, how often the taps are used and thereby the flow in the system. The higher flow the less and slower biofilm formation. It is important to reduce the number of taps to a minimum to ovoid ＂dead ends＂ if they are not or only seldom used. Alternatively all taps could be opened automatically regularly. It is important to establish precautions to ovoid contamination of the water system in the period from when it is established until the building is taken in use. The period can be several months during which the system can act as a ＂dead end＂ if no precautions, such as regularly opening of all taps, are taken. The microbiological quality of the water in the system should be controlled before the building is taken in use. In a new building, where the water supply and the water in the building was not controlled before the building was taken in use, extremely high total and Legionella germ counts were found. The water was disinfected with low concentrations of chloride with very little effect. After disinfection with high concentrations of chloride for few hours and placing a sterile filter at the water entrance both the total and Legionella germ count decreased to an acceptable level.
基金supported in part by the Department of Biotechnology, Ministry of Science and Technology, Government of India (No. BT/PR14998/GBD/ 27/279/2010)
文摘Polycyclic aromatic hydrocarbons （PAHs） in soil retain for a quite long period due to their hydrophobicity and aggregation properties. Biofilm-forming marine bacterial consortium （named as NCPR）, composed of Stenotrophomonas acidaminiphila NCW702, Alcaligenes faecalis NCW402, Pseudomonas mendocina NR802, Pseudornonas aeruginosa N6P6, and Pseudomonas pseudoalcaligenes NP103, was used for the bioremediation of PAHs in a soil microcosm. Phenanthrene and pyrene were used as reference PAHs. Parameters that can affect PAH degradation, such as chemotaxis, solubility of PAHs in extracellular polymeric substances （EPS）, and catechol 2,3-dioxygenase （C230） activity, were evaluated. P. aeruginosa N6P6 and P. pseudoalcaligenes NP103 showed chemotactic movement towards both the reference PAHs. The solubility of both the PAHs was increased with an increase in EPS concentration （extracted from all the 5 selected isolates）. Significantly （P 〈 0.001） high phenanthrene （70.29%） and pyrene （55.54%） degradation was observed in the bioaugmented soil microcosm. The C230 enzyme activity was significantly （P 〈 0.05） higher in the bioaugmented soil mi- crocosm with phenanthrene added at 173.26 ± 2.06 nmol rain-1 mg-1 protein than with pyrene added at 61.80 ± 2.20 nmol min-1 mg-1 protein. The C230 activity and gas chromatography-mass spectrometer analyses indicated catechol pathway of phenanthrene metabolism. However, the metabolites obtained from the soil microcosm added with pyrene revealed both the catechol and phthalate pathways for pyrene degradation.
基金supported by the Ministry of Science and Technology(MOST)of China(2016YFA0501503 and 2019ZX09721001-004-003)the National Natural Science Foundation of China(31670136,31870127,and 81861138047)+1 种基金the Science and Technology Commission of Shanghai Municipality(19JC1416400)the State Key Laboratory of Drug Research(SIMM2003ZZ-03)。
文摘During infections,bacteria stimulate host cells to produce and release histamine,which is a key mediator of vital cellular processes in animals.However,the mechanisms underlying the bacterial cell’s ability to sense and respond to histamine are poorly understood.Herein,we show that HinK,a Lys R-type transcriptional regulator,is required to evoke responses to histamine in Pseudomonas aeruginosa,an important human pathogen.HinK directly binds to and activates the promoter of genes involved in histamine uptake and metabolism,iron acquisition,and Pseudomonas quinolone signal(PQS)biosynthesis.The transcriptional regulatory activity of HinK is induced when histamine is present,and it occurs when HinK binds with imidazole-4-acetic acid(Im AA),a histamine metabolite whose production in P.aeruginosa depends on the HinK-activated histamine uptake and utilization operon hin DAC-pa0222.Importantly,the inactivation of HinK inhibits diverse pathogenic phenotypes of P.aeruginosa.These results suggest that histamine acts as an interkingdom signal and provide insights into the mechanism used by pathogenic bacteria to exploit host regulatory signals to promote virulence.
