scholarly journals 2,3-Dihydroxybenzoate 3,4-oxygenase from Pseudomonas fluorescens: determination of the site of ring cleavage with a substrate analogue

1970 ◽  
Vol 117 (2) ◽  
pp. 28P-29P ◽  
Author(s):  
D W Ribbons ◽  
P J Senior
Keyword(s):  
Pseudomonas Fluorescens ◽  
Ring Cleavage ◽  
Substrate Analogue

scholarly journals Determination of lethal concentration and antibacterial activity of commonly used disinfectants

1970 ◽  
Vol 1 (4) ◽  
pp. 102-105 ◽  
Author(s):  
M Alam ◽  
MM Rahman ◽  
MJ Foysal ◽  
MN Hossain
Keyword(s):  
Methylene Blue ◽  
Pseudomonas Fluorescens ◽  
Potassium Permanganate ◽  
Malachite Green ◽  
Copper Sulfate ◽  
Pathogenic Bacteria ◽  
Labeo Rohita ◽  
Inhibitory Effect ◽  
Lethal Concentration

The toxic effects of four disinfectants viz., copper sulfate (CuSO4), potassium permanganate (KMnO4), methylene blue and malachite green on fish and fish pathogenic bacteria Aeromonas sp., Pseudomonas fluorescens, Edwardsiella sp. and Flavobacterium sp. were investigated. Lethal concentration of the disinfectants to fingerlings of Labeo rohita was determined in aquarium by standard method. Lethal concentration of copper sulfate (CuSO4), potassium permanganate (KMnO4), methylene blue and malachite green against fish were found in 0.75ppm, 7ppm, 6ppm and 0.5ppm at 21.4hrs, 18hrs, 9.5hrs and 1.40hrs, respectively. Methylene blue at 4ppm and 5ppm concentration inhibited the growth of Pseudomonas fluorescens and 6ppm concentration suppressed the growth of Aeromonas sp. Copper sulfate (CuSO4) was effective only against Edwardsiella sp at concentration of 10ppm and 8ppm. Malachite green repressed the growth of all four tasted bacteria at a concentration of 1ppm. Potassium permanganate (KMnO4) was failed to exhibit any inhibitory effect on the bacteria even at 30ppm concentration. DOI: http://dx.doi.org/10.3329/ijns.v1i4.9738 IJNS 2011 1(4): 102-105

scholarly journals Degradation of Phenol via Meta Cleavage Pathway by Pseudomonas fluorescens PU1

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Md. Mahiudddin ◽  
A. N. M. Fakhruddin ◽  
Abdullah-Al-Mahin
Keyword(s):  
Phenolic Compounds ◽  
Pseudomonas Fluorescens ◽  
Phenol Degradation ◽  
Carbon Sources ◽  
Soil Microflora ◽  
Ring Cleavage ◽  
Cell Extracts ◽  
Polluted Sites ◽  
Important Means ◽  
Biodegradation Efficiency

Degradation of phenolics by members of soil microflora is an important means by which these substances are removed from the environment thus reducing environmental pollution. Biodegradation by microorganisms offers unique opportunities to destroy or render phenolic compounds. A bacterium, PU1, identified as Pseudomonas fluorescens PU1, was investigated for its ability to grow on and degrade phenols as sole carbon sources in aerobic shaking batch culture. The organism degraded up to 1000 ppm of phenol using meta cleavage pathway. The pathways for phenol degradation were proposed by the identification of metabolites and assay of ring cleavage enzymes in cell extracts. Phenol was degraded via catechol with subsequent metaring cleavage. Cell growth increased as the phenol concentrations increased up to 1000 ppm phenol. The biodegradation efficiency, degradation extent, and metabolic pathway of phenol were determined to provide useful clues for further application of this isolate in the engineered bioremediation systems. The paper's results suggest that Pseudomonas fluorescens PU1 strain could be a good candidate for remediation of phenol contaminants from heavily polluted sites.

Determination of the extracellular lipases of Pseudomonas fluorescens spp. in skim milk with the β-naphthyl caprylate assay

1986 ◽  
Vol 53 (2) ◽  
pp. 301-312 ◽  
Author(s):  
Robin C. McKellar ◽  
Hilaire Cholette
Keyword(s):  
Pseudomonas Fluorescens ◽  
Lipase Activity ◽  
Skim Milk ◽  
Maximum Activity ◽  
Apparent Loss ◽  
Colony Forming Units ◽  
Native Lipase ◽  
Hydrolysis Of ◽  
Diffusion Assay

SUMMARYA method based on the hydrolysis of β-naphthyl caprylate (β-NC) has been developed for quantitating extracellular lipase from Pseudomonas fluorescens. The assay was extremely sensitive to skim milk (SM); as little as 0·02 ml raw SM in a 2·0 ml reaction mixture resulted in an apparent loss of 50% of the lipase activity. Activity improved 3-fold when trypsin (50 μg/ml) was included in the reaction mixture. When super-simplex optimization was used to determine the optimum levels of β-NC, Na taurocholate (NaTC), SM/lipase mixture and trypsin for maximum activity, NaTC was found to be unnecessary for activity. Subsequent addition of 15 mM-NaTC resulted in 80% loss of activity. On the other hand, NaTC was required for native lipase activity in the presence of SM. Native lipase was completely inhibited by heating at 70 °C for 2 min, while B52 lipase retained 75% of its activity under the same conditions. The assay was able to detect lipase produced by Ps. fluorescens B52 in SM at 5 °C when the cell density exceeded 108 colony forming units/ml. The presence of butterfat (3°5%) in the SM assay inhibited B52 lipase by 97%. The β-NC assay gave results comparable to the tributyrin agar diffusion assay using cell-free extracts of ten strains of common dairy psychrotrophs. The results suggest that the β-NC assay may be useful for determining lipase activity in raw SM.

scholarly journals Determination of Key Metabolites during Biodegradation of Hexahydro-1,3,5-Trinitro-1,3,5-Triazine with Rhodococcus sp. Strain DN22

2002 ◽  
Vol 68 (1) ◽  
pp. 166-172 ◽  
Author(s):  
Diane Fournier ◽  
Annamaria Halasz ◽  
Jim Spain ◽  
Petr Fiurasek ◽  
Jalal Hawari
Keyword(s):  
Molecular Mass ◽  
Degradation Products ◽  
Degradation Pathway ◽  
Aerobic Biodegradation ◽  
Ring Cleavage ◽  
Molecular Formula ◽  
Dead End ◽  
Liquid Chromatographic ◽  
Chromatographic Mass

ABSTRACT Rhodococcus sp. strain DN22 can convert hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to nitrite, but information on degradation products or the fate of carbon is not known. The present study describes aerobic biodegradation of RDX (175 μM) when used as an N source for strain DN22. RDX was converted to nitrite (NO2 −) (30%), nitrous oxide (N2O) (3.2%), ammonia (10%), and formaldehyde (HCHO) (27%), which later converted to carbon dioxide. In experiments with ring-labeled [15N]-RDX, gas chromatographic/mass spectrophotometric (GC/MS) analysis revealed N2O with two molecular mass ions: one at 44 Da, corresponding to 14N14NO, and the second at 45 Da, corresponding to 15N14NO. The nonlabeled N2O could be formed only from -NO2, whereas the 15N-labeled one was presumed to originate from a nitramine group (15N-14NO2) in RDX. Liquid chromatographic (LC)-MS electrospray analyses indicated the formation of a dead end product with a deprotonated molecular mass ion [M-H] at 118 Da. High-resolution MS indicated a molecular formula of C2H5N3O3. When the experiment was repeated with ring-labeled [15N]-RDX, the [M-H] appeared at 120 Da, indicating that two of the three N atoms in the metabolite originated from the ring in RDX. When [U-14C]-RDX was used in the experiment, 64% of the original radioactivity in RDX incorporated into the metabolite with a molecular weight (MW) of 119 (high-pressure LC/radioactivity) and 30% in 14CO2 (mineralization) after 4 days of incubation, suggesting that one of the carbon atoms in RDX was converted to CO2 and the other two were incorporated in the ring cleavage product with an MW of 119. Based on the above stoichiometry, we propose a degradation pathway for RDX based on initial denitration followed by ring cleavage to formaldehyde and the dead end product with an MW of 119.

scholarly journals Biodegradation of 2,4-dichlorophenoxyacetic acid and 4-chlorophenol in contaminated soils by Pseudomonas fluorescens strain HH

2019 ◽  
Vol 41 (3) ◽  
Author(s):  
Ha Danh Duc ◽  
Nguyen Thi Oanh ◽  
Nguyen Gia Hien
Keyword(s):  
Pseudomonas Fluorescens ◽  
Contaminated Soils ◽  
Degradation Pathway ◽  
Chemical Degradation ◽  
Dichlorophenoxyacetic Acid ◽  
Loamy Soil ◽  
Moisture Contents ◽  
2,4 Dichlorophenoxyacetic Acid ◽  
Autochthonous Microorganisms

Herbicides with 2,4-dichlorophenoxyacetic acid (2,4D) has been commonly used to control weeds and widely detected in environments. In this study, biodegradating activity of Pseudomonas fluorescens HH on 2,4D and 4-chlorophenol (4CP) in soil was carried out. The inoculation with Pseudomonas fluorescens HH in soils increased the degradation of 4CP and 2,4D by from 47.0% to 51.4% and from 38.4% to 47.4%, respectively, compared to the degradation by autochthonous microorganisms. Pseudomonas fluorescens HH could degrade well 2,4D and 4CP in various soils, but the most efficient chemical removal was observed when they were in the loamy soil. Moreover, the efficiency of chemical degradation was significantly affected by the moisture contents with the highest performance of degradation at 10 and 20% soil moisture. Also, the addition of nitrogen (N), phosphorous (P) and potassium (K) stimulated the dissipation rates. The determination of degradation pathway for 2,4D in Pseudomonas fluorescens HH indicated that 2,4-dichlorophenol (2,4DCP) and 4CP were formed as metabolites.

scholarly journals Comparison of Planktonic and Biofilm Cultures of Pseudomonas fluorescens DSM 8341 Cells Grown on Fluoroacetate

2009 ◽  
Vol 75 (9) ◽  
pp. 2899-2907 ◽  
Author(s):  
Barry Heffernan ◽  
Cormac D. Murphy ◽  
Eoin Casey
Keyword(s):  
Cell Cycle ◽  
Pseudomonas Fluorescens ◽  
Biofilm Reactor ◽  
Overflow Metabolism ◽  
Planktonic Cells ◽  
Cell Cycle Kinetics ◽  
Physiological Properties ◽  
Similar Growth ◽  
Spatial Stratification

ABSTRACT Comparisons between the physiological properties of Pseudomonas fluorescens biofilm cells grown in a tubular biofilm reactor and planktonic cells grown in a chemostat were performed. Fluoroacetate was the sole carbon source for all experiments. The performance of cells was assessed using cell cycle kinetics and by determining specific fluoroacetate utilization rates. Cell cycle kinetics were studied by flow cytometry in conjunction with the fluorescent stain propidium iodide. Determination of the DNA content of planktonic and biofilm cultures showed little difference between the two modes of growth. Cultures with comparable specific glycolate utilization rates had similar percentages of cells in the B phase of the cell cycle, indicating similar growth rates. Specific fluoroacetate utilization rates showed the performance of planktonic cells to be superior to that of biofilm cells, with more fluoroacetate utilized per cell at similar specific fluoroacetate loading rates. A consequence of this decreased biofilm performance was the accumulation of glycolate in the effluent of biofilm cultures. This accumulation of glycolate was not observed in the effluent of planktonic cultures. Spatial stratification of oxygen within the biofilm was identified as a possible explanation for the overflow metabolism of glycolate and the decreased performance of the biofilm cells.

scholarly journals Microbial Transformation of Selected Flavanones as a Method of Increasing the Antioxidant Properties

2010 ◽  
Vol 65 (1-2) ◽  
pp. 55-60 ◽  
Author(s):  
Edyta Kostrzewa-Susłow ◽  
Jadwiga Dmochowska-Gładysz ◽  
Tomasz Janeczko
Keyword(s):  
Antiradical Activity ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Microbial Transformation ◽  
Ring Cleavage ◽  
Microbial Transformations ◽  
The Impact

Antioxidant properties of substrates [fl avanone (1), 6-hydroxy- (2), 7-hydroxy- (3), 5,7,4’- trihydroxy- (5), and 7-methoxyfl avanone (4)] and products of their microbial transformations, comprising hydroxylation, O-methylation, stereospecifi c reduction, dehydrogenation, and C-ring cleavage of the benzo-γ-pyrone system, were determined. Measurements of the antiradical activity (expressed as IC50 value) of both the substrates and the products led to the determination of the impact of type and location of substituents in the tested fl avonoids on changes in their antioxidant activities.

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