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Microbial Ecology Nov 2009Arbuscular mycorrhizal (AM) symbiosis and plant-growth-promoting rhizobacterium (PGPR) can alleviate the effects of water stress in plants, but it is unknown whether...
Differential effects of Pseudomonas mendocina and Glomus intraradices on lettuce plants physiological response and aquaporin PIP2 gene expression under elevated atmospheric CO2 and drought.
Arbuscular mycorrhizal (AM) symbiosis and plant-growth-promoting rhizobacterium (PGPR) can alleviate the effects of water stress in plants, but it is unknown whether these benefits can be maintained at elevated CO2. Therefore, we carried out a study where seedlings of Lactuca sativa were inoculated with the AM fungus (AMF) Glomus intraradices N.C. Schenk & G.S. Sm. or the PGPR Pseudomonas mendocina Palleroni and subjected to two levels of watering and two levels of atmospheric CO2 to ascertain their effects on plant physiological parameters and gene expression of one PIP aquaporin in roots. The inoculation with PGPR produced the greatest growth in lettuce plants under all assayed treatments as well as the highest foliar potassium concentration and leaf relative water content under elevated [CO2] and drought. However, under such conditions, the PIP2 gene expression remained almost unchanged. G. intraradices increased significantly the AMF colonization, foliar phosphorus concentration and leaf relative water content in plants grown under drought and elevated [CO2]. Under drought and elevated [CO2], the plants inoculated with G. intraradices showed enhanced expression of the PIP2 gene as compared to P. mendocina or control plants. Our results suggest that both microbial inoculation treatments could help to alleviate drought at elevated [CO2]. However, the PIP2 gene expression was increased only by the AMF but not by the PGPR under these conditions.
Topics: Aquaporins; Biomass; Carbon Dioxide; Droughts; Gene Expression Regulation, Plant; Genes, Plant; Lactuca; Mycorrhizae; Phosphorus; Plant Leaves; Plant Proteins; Plant Roots; Plant Transpiration; Pseudomonas mendocina; Symbiosis; Water
PubMed: 19495853
DOI: 10.1007/s00248-009-9544-6 -
Journal of Basic Microbiology Oct 2010A strain of Pseudomonas mendocina producing extracellular lipase was isolated from soil. The bacterium accumulates lipase in culture fluid when grown aerobically at 30...
A strain of Pseudomonas mendocina producing extracellular lipase was isolated from soil. The bacterium accumulates lipase in culture fluid when grown aerobically at 30 °C for 24 h in a medium composed of olive oil (1%) as substrate. Pseudomonas mendocina lipase was optimally active at pH 9.0, temperature of 50 °C and was found to be stable between pH 7.0-11.0. The lipase was inhibited by detergents such as SDS and Tween-80. The enzyme was stable in various organic solvents tested with maximum stability in chloroform followed by toluene and exhibited 1-3 regiospecificity for hydrolytic reaction. This lipase was capable of hydrolyzing a variety of lipidic substrates and is mainly active towards synthetic triglycerides and fatty acid esters that possess a butyryl group. Metal ions like Mg(2+), Ca(2+) and Na(+) stimulated lipase activity, whereas, Cu(2+), Mn(2+) and Hg(2+) ions caused inhibition.
Topics: Bacterial Proteins; Detergents; Enzyme Stability; Hydrogen-Ion Concentration; Lipase; Metals; Pseudomonas mendocina; Solvents; Substrate Specificity; Temperature
PubMed: 20586067
DOI: 10.1002/jobm.200900377 -
Bioresource Technology Feb 2024A salt-tolerant strain, Pseudomonas mendocina A4, was isolated from brackish-water ponds showing simultaneous heterotrophic nitrification-aerobic denitrification and...
Simultaneous aerobic nitrogen and phosphate removal capability of novel salt-tolerant strain, Pseudomonas mendocina A4: Characterization, mechanism and application potential.
A salt-tolerant strain, Pseudomonas mendocina A4, was isolated from brackish-water ponds showing simultaneous heterotrophic nitrification-aerobic denitrification and phosphorus removal capability. The optimal conditions for nitrogen and phosphate removal of strain A4 were pH 7-8, carbon/nitrogen ratio 10, phosphorus/nitrogen ratio 0.2, temperature 30 °C, and salinity range of 0-5 % using sodium succinate as the carbon source. The nitrogen and phosphate removal efficiencies were 96-100 % and 88-96 % within 24 h, respectively. The nitrogen and phosphate removal processes were matched with the modified Gompertz model, and the underlying mechanisms were confirmed by the activities of key metabolic enzymes. Under 10 % salinity, the immobilization technology was employed to enhance the nitrogen and phosphate removal efficiencies of strain A4, achieving 87 % and 76 %, respectively. These findings highlight the potential application of strain A4 in both freshwater and marine culture wastewater treatment.
Topics: Denitrification; Phosphates; Pseudomonas mendocina; Nitrogen; Aerobiosis; Nitrification; Phosphorus; Heterotrophic Processes; Carbon; Nitrites; Nitrogen Radioisotopes
PubMed: 37989421
DOI: 10.1016/j.biortech.2023.130047 -
Methods in Enzymology 1997
Topics: Amino Acid Substitution; Cloning, Molecular; Crystallography, X-Ray; Escherichia coli; Kinetics; Lipase; Models, Molecular; Models, Structural; Mutagenesis, Site-Directed; Protein Conformation; Protein Engineering; Protein Folding; Protein Structure, Secondary; Protein Structure, Tertiary; Pseudomonas; Recombinant Proteins; Thermodynamics
PubMed: 9379942
DOI: 10.1016/s0076-6879(97)84020-7 -
Current Microbiology Aug 2009Evident effect of an algicidal bacterium Pseudomonas mendocina on the growth and antioxidant system of Aphanizomenon flos-aquae was detected in this experiment. Seven...
Evident effect of an algicidal bacterium Pseudomonas mendocina on the growth and antioxidant system of Aphanizomenon flos-aquae was detected in this experiment. Seven parameters including the chlorophyll a contents, Fv/Fm values, reactive oxygen species (ROS), malonaldehyde (MDA), catalase (CAT), peroxide dismutase (POD), and superoxide dismutase (SOD) were tested in the cyanobacterium A. flos-aquae cells after inoculation with the algicidal bacterium Pseudomonas mendocina DC10. It was shown from the experiment that the growth of the treated cyanobacterium A. flos-aquae was significantly restrained, which was expressed as great reductions in the chlorophyll a contents and Fv/Fm values. At the same time, the treated cyanobacterial cells exhibited an obvious increase in the production of ROS and MDA compared with the control. CAT and POD activities in the treated group kept at high level, however, they both reduced significantly on day 6. SOD activities in the treated A. flos-aquae showed obvious declines after inoculation, and great augmentations on day 3 and 4, thereafter, they kept in a declining tendency. The results showed the oxidative stresses induced by the bacterium could be a killing agent of the cyanobacterium A. flos-aquae cells.
Topics: Antibiosis; Antioxidants; Aphanizomenon; Catalase; Chlorophyll; Chlorophyll A; Malondialdehyde; Oxidative Stress; Peroxidase; Pseudomonas mendocina; Reactive Oxygen Species
PubMed: 19365689
DOI: 10.1007/s00284-009-9404-0 -
Research in Microbiology May 2010Pseudomonas mendocina carrying a novel class 1 integron containing an IMP-8 gene was isolated from an inanimate surface in a female ward sanitary facility of the...
Pseudomonas mendocina carrying a novel class 1 integron containing an IMP-8 gene was isolated from an inanimate surface in a female ward sanitary facility of the Hospital Infante D. Pedro, Aveiro, Portugal. Hybridization with the integrase gene (intI1) and 16S rDNA revealed that the integron is chromosomally located. Here we report for the first time the presence of an IMP-8 metallo-beta-lactamase gene in the Pseudomonas genus.
Topics: Bacterial Proteins; Equipment and Supplies, Hospital; Humans; Integrons; Molecular Sequence Data; Portugal; Pseudomonas mendocina; beta-Lactamases
PubMed: 20381610
DOI: 10.1016/j.resmic.2010.03.004 -
The Journal of Hospital Infection Jan 2011Pseudomonas mendocina was first isolated in the 1970s from soil and water samples collected in the province of Mendoza, Argentina. Its recovery from human clinical...
Pseudomonas mendocina was first isolated in the 1970s from soil and water samples collected in the province of Mendoza, Argentina. Its recovery from human clinical specimens other than urine and leg ulcers was not documented until 1992, when a case report of an endocarditis caused by P. mendocina was published. We report the detection of P. mendocina in diagnostic stem cell cultures in the haematology unit, which initiated an outbreak investigation after identification of P. mendocina from three diagnostic stem cell cultures. Culture of a reagent used for the preparation of the diagnostic stem cell cultures revealed P. mendocina. Further outbreak investigation at the manufacturing site confirmed contamination of the product. This is the first report of an outbreak caused by P. mendocina from a commercial 'sterile' product. We conclude that this environmental pathogen has the potential to cause contamination of reagents used in clinical settings. Detection of P. mendocina should alert hospital personnel to possible product contamination.
Topics: Argentina; Cells, Cultured; Humans; Pseudomonas mendocina; Stem Cells
PubMed: 21146254
DOI: 10.1016/j.jhin.2010.08.008 -
Environmental Microbiology Reports Jun 2010Pseudomonas mendocina KR1 oxidizes the gasoline oxygenate methyl tertiary butyl ether (MTBE) to tertiary butyl alcohol (TBA) during growth on C5 -C8 n-alkanes. We have...
Pseudomonas mendocina KR1 oxidizes the gasoline oxygenate methyl tertiary butyl ether (MTBE) to tertiary butyl alcohol (TBA) during growth on C5 -C8 n-alkanes. We have further explored oxidation of ether oxygenates by this strain to help identify the enzyme that catalyses these reactions. High levels of MTBE-oxidizing activity occurred in resting cells grown on C5 -C8 n-alkanes. Lower activities occurred in cells grown on longer-chain n-alkanes (C9 -C11 ) and 1°-alcohols (C5 -C10 ). N-octane-grown cells also oxidized tertiary amyl methyl ether (TAME) to tertiary amyl alcohol (TAA), but did not oxidize ethyl tertiary butyl ether (ETBE), TBA or TAA. A 39 kDa polypeptide in whole cell extracts of n-octane-grown cells strongly cross-reacted with an anti-AlkB polyclonal antiserum in an SDS-PAGE/immunoblot. This polypeptide was absent or less abundant in cells grown on dextrose, dextrose plus dicyclopropylketone or 1-octanol. N-octane-grown cells of Pseudomonas aeruginosa strains KSLA-473 and ATCC 17423 oxidized MTBE and TAME but not ETBE. N-hexadecane-grown cells of these strains and strain PAO1 did not oxidize any of the oxygenates tested. Our results indicate ether oxygenate-degrading activity in alkane-utilizing pseudomonads is consistently observed with close homologues of the GPo1 non-haem-iron alkane hydroxylases but is otherwise not a consistent catalytic feature of these diverse enzymes.
PubMed: 23766116
DOI: 10.1111/j.1758-2229.2010.00155.x -
Chemistry (Weinheim An Der Bergstrasse,... Apr 2023Monooxygenases, an important class of enzymes, have been the subject of enzyme engineering due to their high activity and versatile substrate scope. Reactions performed...
Monooxygenases, an important class of enzymes, have been the subject of enzyme engineering due to their high activity and versatile substrate scope. Reactions performed by these biocatalysts have long been monitored by a colorimetric method involving the coupling of a dye precursor to naphthalene hydroxylation products generated by the enzyme. Despite the popularity of this method, we found the dye product to be unstable, preventing quantitative readout. By incorporating an extraction step to solubilize the dye produced, we have improved this assay to the point where quantitation of enzyme activity is possible. Further, by incorporating spectral deconvolution, we have, for the first time, enabled independent quantification of the two possible regioisomeric products: 1-naphthol and 2-naphthol. Previously, such analysis was only possible with chromatographic separation, increasing the cost and complexity of analysis. The efficacy of our improved workflow was evaluated by monitoring the activity of a toluene-4-monooxygenase enzyme from Pseudomonas mendocina KR-1. Our colorimetric regioisomer quantification was found to be consistent with chromatographic analysis by HPLC. The development and validation of a quantitative colorimetric assay for monooxygenase activity that enables regioisomeric distinction and quantification represents a significant advance in analytical methods to monitor enzyme activity. By maintaining facile, low-cost, high-throughput readout while incorporating quantification, this assay represents an important alternative to more expensive chromatographic quantification techniques.
Topics: Oxygenases; Mixed Function Oxygenases
PubMed: 36593585
DOI: 10.1002/chem.202203322 -
Journal of Bacteriology Dec 2002The tmoABCDEF genes encode the toluene-4-monooxygenase from Pseudomonas mendocina KR1. Upstream from the tmoA gene an open reading frame, tmoX, encoding a protein 83%...
The tmoABCDEF genes encode the toluene-4-monooxygenase from Pseudomonas mendocina KR1. Upstream from the tmoA gene an open reading frame, tmoX, encoding a protein 83% identical to TodX (todX being the initial gene in the todXFC1C2BADEGIH operon from Pseudomonas putida DOT-T1E) was found. The tmoX gene is also the initial gene in the tmoXABCDEF gene cluster. The transcription initiation point from the tmoX promoter was mapped, and the sequence upstream revealed striking identity with the promoter of the tod operon of P. putida. The tod operon is regulated by a two-component signal transduction system encoded by the todST genes. Two novel genes from P. mendocina KR1, tmoST, were rescued by complementation of a P. putida DOT-T1E todST knockout mutant, whose gene products shared about 85% identity with TodS-TodT. We show that transcription from P(tmoX) and P(todX) can be mediated by TmoS-TmoT or TodS-TodT, in the presence of toluene, revealing cross-regulation between these two catabolic pathways.
Topics: Bacterial Proteins; Multigene Family; Promoter Regions, Genetic; Protein Kinases; Pseudomonas; Pseudomonas putida; Signal Transduction; Toluene; Trans-Activators; Transcription, Genetic
PubMed: 12446657
DOI: 10.1128/JB.184.24.7062-7067.2002