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Sample records for fluorescens bd5 isolated

  1. Isolation and characterization of two new lipopeptide biosurfactants produced by Pseudomonas fluorescens BD5 isolated from water from the Arctic Archipelago of Svalbard

    Czech Academy of Sciences Publication Activity Database

    Janek, T.; Lukaszewicz, M.; Řezanka, Tomáš; Krasowska, A.

    2010-01-01

    Roč. 101, č. 15 (2010), s. 6118-6123 ISSN 0960-8524 Institutional research plan: CEZ:AV0Z50200510 Keywords : Pseudomonas fluorescens BD5 * Lipopeptide * Pseudofactins Subject RIV: EE - Microbiology, Virology Impact factor: 4.365, year: 2010

  2. Isolation and characterization of a T7-like lytic phage for Pseudomonas fluorescens

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    Neubauer Peter

    2008-10-01

    Full Text Available Abstract Background Despite the proven relevance of Pseudomonas fluorescens as a spoilage microorganism in milk, fresh meats and refrigerated food products and the recognized potential of bacteriophages as sanitation agents, so far no phages specific for P. fluorescens isolates from dairy industry have been closely characterized in view of their lytic efficiency. Here we describe the isolation and characterization of a lytic phage capable to infect a variety of P. fluorescens strains isolated from Portuguese and United States dairy industries. Results Several phages were isolated which showed a different host spectrum and efficiency of lysis. One of the phages, phage ϕIBB-PF7A, was studied in detail due to its efficient lysis of a wide spectrum of P. fluorescens strains and ribotypes. Phage ϕIBB-PF7A with a head diameter of about 63 nm and a tail size of about 13 × 8 nm belongs morphologically to the Podoviridae family and resembles a typical T7-like phage, as analyzed by transmission electron microscopy (TEM. The phage growth cycle with a detected latent period of 15 min, an eclipse period of 10 min, a burst size of 153 plaque forming units per infected cell, its genome size of approximately 42 kbp, and the size and N-terminal sequence of one of the protein bands, which gave similarity to the major capsid protein 10A, are consistent with this classification. Conclusion The isolated T7-like phage, phage ϕIBB-PF7A, is fast and efficient in lysing different P. fluorescens strains and may be a good candidate to be used as a sanitation agent to control the prevalence of spoilage causing P. fluorescens strains in dairy and food related environments.

  3. Pseudomine, an isoxazolidone with siderophoric activity from Pseudomonas fluorescens AH2 isolated from Lake Victorian Nile Perch

    DEFF Research Database (Denmark)

    Anthoni, U.; Christophersen, C.; Nielsen, P.H.

    1995-01-01

    A siderophore, pseudomonine, and sodium salicylate were isolated from the culture broth of iron-deficient cultures of Pseudomonas fluorescens AH2 isolated from the surface of spoiled Nile Perch from Lake Victoria......A siderophore, pseudomonine, and sodium salicylate were isolated from the culture broth of iron-deficient cultures of Pseudomonas fluorescens AH2 isolated from the surface of spoiled Nile Perch from Lake Victoria...

  4. Production and properties of biosurfactants from a newly isolated Pseudomonas fluorescens HW-6 growing on hexandecane

    Energy Technology Data Exchange (ETDEWEB)

    Vasileva-Tonkova, E.; Galabova, D. [Bulgarian Academy of Sciences, Dept. of Microbial Biochemistry, Sofia (Bulgaria); Stoimenova, E.; Lalchev, Z. [Dept. of Biochemistry, Sofia Univ. ' ' St. Kliment Ohridski' ' , Sofia (Bulgaria)

    2006-07-15

    The newly isolated from industrial wastewater Pseudomonas fluorescens strain HW-6 produced glycolipid biosurfactants at high concentrations (1.4-2.0 g 1{sup -1}) when grown on hexadecane as a sole carbon source. Biosurfactants decreased the surface tension of the air/water interface by 35 mN m{sup -1} and possessed a low critical micelle concentration value of 20 mg 1{sup -1}, which indicated high surface activity. They efficiently emulsified aromatic hydrocarbons, kerosene, n-paraffins and mineral oils. Biosurfactant production contributed to a significant increase in cell hydrophobicity correlated with an increased growth of the strain on hexadecane. The results suggested that the newly isolated strain of Ps. fluorescens and produced glycolipid biosurfactants with effective surface and emulsifying properties are very promising and could find application for bioremediation of hydrocarbon-polluted sites. (orig.)

  5. Chitinolytic activity of Pseudomonas fluorescens isolates from barley and sugar beet rhizosphere.

    Science.gov (United States)

    Neiendam Nielsen M; Sørensen

    1999-11-01

    Twelve isolates of Pseudomonas fluorescens, isolated from barley and sugar beet rhizosphere as antagonists towards the plant pathogenic microfungi Rhizoctonia solani and Pythium ultimum, showed chitinolytic activity in batch cultures when grown in media without exogenous chitin. Enzyme tests in cultures demonstrated a complete array of chitinolytic enzymes. Endochitinase and chitobiosidase activities seemed to be tightly coupled in the isolates, while there was no relationship to N-acetyl-glucosaminidase activity. Endochitinase activity, showing hydrolysis of chitin polymers, was found to be extracellular in all isolates, although the most active isolates also retained a cell-bound fraction. Isoelectric focusing gel electrophoresis of supernatants containing extracellular enzyme activity showed that all isolates produced one native endochitinase in logarithmic phase. This enzyme was subsequently modified into several isozymes by extracellular processing as the cultures aged in stationary phase. The 12 isolates could be grouped into seven isozymic patterns. Detailed studies of three selected isolates showed that extracellular release of endochitinase activity also took place in stationary phase. The results, however, indicated that in stationary phase regulation of both the overall production of native enzyme and the subsequent formation of isozymes were different among the P. fluorescens isolates.

  6. Biodegradation of didecyldimethylammonium chloride by Pseudomonas fluorescens TN4 isolated from activated sludge.

    Science.gov (United States)

    Nishihara, T; Okamoto, T; Nishiyama, N

    2000-04-01

    Bacteria that degrade didecyldimethylammonium chloride (DDAC) were isolated from activated sludge from a municipal sewage treatment plant by enrichment culture with DDAC as a sole carbon source. One of the isolates, Pseudomonas fluorescens TN4, degraded DDAC to produce decyldimethylamine and subsequently, dimethylamine, as the intermediates. The TN4 strain also assimilated the other quaternary ammonium compounds (QACs), alkyltrimethyl- and alkylbenzyldimethyl-ammonium salts, but not alkylpyridinium salts. TN4 was highly resistant to these QACs and degraded them by an N-dealkylation process. These data mean that there are some QAC-resistant and QAC-degrading bacteria such as TN4 in the environment.

  7. Nonribosomal peptides, key biocontrol components for Pseudomonas fluorescens In5, isolated from a Greenlandic suppressive soil.

    Science.gov (United States)

    Michelsen, Charlotte F; Watrous, Jeramie; Glaring, Mikkel A; Kersten, Roland; Koyama, Nobuhiro; Dorrestein, Pieter C; Stougaard, Peter

    2015-03-17

    Potatoes are cultivated in southwest Greenland without the use of pesticides and with limited crop rotation. Despite the fact that plant-pathogenic fungi are present, no severe-disease outbreaks have yet been observed. In this report, we document that a potato soil at Inneruulalik in southern Greenland is suppressive against Rhizoctonia solani Ag3 and uncover the suppressive antifungal mechanism of a highly potent biocontrol bacterium, Pseudomonas fluorescens In5, isolated from the suppressive potato soil. A combination of molecular genetics, genomics, and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) imaging mass spectrometry (IMS) revealed an antifungal genomic island in P. fluorescens In5 encoding two nonribosomal peptides, nunamycin and nunapeptin, which are key components for the biocontrol activity by strain In5 in vitro and in soil microcosm experiments. Furthermore, complex microbial behaviors were highlighted. Whereas nunamycin was demonstrated to inhibit the mycelial growth of R. solani Ag3, but not that of Pythium aphanidermatum, nunapeptin instead inhibited P. aphanidermatum but not R. solani Ag3. Moreover, the synthesis of nunamycin by P. fluorescens In5 was inhibited in the presence of P. aphanidermatum. Further characterization of the two peptides revealed nunamycin to be a monochlorinated 9-amino-acid cyclic lipopeptide with similarity to members of the syringomycin group, whereas nunapeptin was a 22-amino-acid cyclic lipopeptide with similarity to corpeptin and syringopeptin. Crop rotation and systematic pest management are used to only a limited extent in Greenlandic potato farming. Nonetheless, although plant-pathogenic fungi are present in the soil, the farmers do not experience major plant disease outbreaks. Here, we show that a Greenlandic potato soil is suppressive against Rhizoctonia solani, and we unravel the key biocontrol components for Pseudomonas fluorescens In5, one of the potent biocontrol bacteria

  8. Isolation and characterization of antimicrobial cyclic dipeptides from Pseudomonas fluorescens and their efficacy on sorghum grain mold fungi.

    Science.gov (United States)

    Sajeli Begum, Ahil; Basha, Shaik Ameer; Raghavendra, Govardhanam; Kumar, Mallela Venkata Nagesh; Singh, Yukthi; Patil, Jagannath V; Tanemura, Yuhei; Fujimoto, Yoshinori

    2014-01-01

    This study was aimed at isolation and characterization of natural antifungal compounds for grain mold, a key parasitic fungal disease of sorghum. Pseudomonas fluorescens strain isolated from rhizosphere of groundnut crop was selected as a source. Its biocontrolling ability was assessed by testing some biochemical attributes such as phosphate-solubilization, and HCN, NH3 , indole-3-acetic acid, and siderophore production. The strain showed positive result for all except indole-3-acetic acid, revealing its suitability for a further study. The antibiotic-sensitivity pattern of the strain against 43 antibiotics was also established, which showed resistance to 15 antibiotics. The efficacy of P. fluorescens strain against grain mold was identified by dual culture technique. Hundred percent inhibition was found against Fusarium moniliforme, an important causative agent of this disease. The strain was fermented for secondary metabolites and extracted with AcOEt. Chromatographic separation of the extract yielded four known compounds, cyclo(L-Pro-L-Phe) (1), cyclo(trans-4-hydroxy-L-Pro-L-Leu) (2), cyclo(trans-4-hydroxy-L-Pro-L-Phe) (3), and cyclo(Gly-L-Pro) (4), which were characterized by spectral analysis and optical rotation. The crude extract, a mixture of 2 and 3, and isolated 1 were proved to be significantly effective against grain mold fungi. This is the first report on production of these cyclic dipeptides by P. fluorescens and their antagonistic properties. Copyright © 2014 Verlag Helvetica Chimica Acta AG, Zürich.

  9. The effect of rhamnolipid biosurfactant produced by Pseudomonas fluorescens on model bacterial strains and isolates from industrial wastewater.

    Science.gov (United States)

    Vasileva-Tonkova, Evgenia; Sotirova, Anna; Galabova, Danka

    2011-02-01

    In this study, the effect of rhamnolipid biosurfactant produced by Pseudomonas fluorescens on bacterial strains, laboratory strains, and isolates from industrial wastewater was investigated. It was shown that biosurfactant, depending on the concentration, has a neutral or detrimental effect on the growth and protein release of model Gram (+) strain Bacillus subtilis 168. The growth and protein release of model Gram (-) strain Pseudomonas aeruginosa 1390 was not influenced by the presence of biosurfactant in the medium. Rhamnolipid biosurfactant at the used concentrations supported the growth of some slow growing on hexadecane bacterial isolates, members of the microbial community. Changes in cell surface hydrophobicity and permeability of some Gram (+) and Gram (-) isolates in the presence of rhamnolipid biosurfactant were followed in experiments in vitro. It was found that bacterial cells treated with biosurfactant became more or less hydrophobic than untreated cells depending on individual characteristics and abilities of the strains. For all treated strains, an increase in the amount of released protein was observed with increasing the amount of biosurfactant, probably due to increased cell permeability as a result of changes in the organization of cell surface structures. The results obtained could contribute to clarify the relationships between members of the microbial community as well as suggest the efficiency of surface properties of rhamnolipid biosurfactant from Pseudomonas fluorescens making it potentially applicable in bioremediation of hydrocarbon-polluted environments.

  10. Antimicrobial activity of olive mill wastewater extract against Pseudomonas fluorescens isolated from mozzarella cheese

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    Rossana Roila

    2016-05-01

    Full Text Available Olive mill wastewater polyphenol extract was tested for antimicrobial activity against 64 strains of Pseudomonas fluorescens responsible for mozzarella discolouration. The extract showed a minimum inhibitory concentration (MIC50 value of 5 mg/mL and a MIC90 value of 7 mg/mL. The MBC50 and MBC90 values corresponded to 6 and 8 mg/mL, respectively. The MIC concentration (7 mg/mL was demonstrated to have a bacteriostatic effect while maintaining the bacterial concentration on the levels of the inoculum for 48 hours. The 3/2 MIC concentration was responsible for four logs CFU/mL depletion in colony count after 24 h. As the extract concentration decreased from MIC value, no inhibitory effects were recorded.

  11. Nunamycin and Nunapeptin: Two novel cyclic peptides are key components of the antimicrobial activity of the Greenlandic isolate Pseudomonas fluorescens In5

    DEFF Research Database (Denmark)

    Hennessy, Rosanna Catherine; Phippen, Christopher; Nielsen, Kristian F.

    Pseudomonas spp. are a rich source of secondary metabolites including bioactive non-ribosomal peptides (NRPs) and polyketides. NRPs are synthesised in large assembly lines by multi-domain modular enzymes known as NRP-synthetases (NRPS). Nunamycin and nunapeptin are two cyclic NRPs synthesised...... by the Greenlandic isolate P. fluorescens In5. Nunamycin shows antifungal activity against the basidiomycete Rhizoctonia solani whereas the only partially structure elucidated nunapeptin appears most active against the ascomycete Fusarium graminearum and the oomycete Pythium aphanidermatum. Originally isolated from...

  12. Comparative genomics of Pseudomonas fluorescens subclade III strains from human lungs.

    Science.gov (United States)

    Scales, Brittan S; Erb-Downward, John R; Huffnagle, Ian M; LiPuma, John J; Huffnagle, Gary B

    2015-12-07

    While the taxonomy and genomics of environmental strains from the P. fluorescens species-complex has been reported, little is known about P. fluorescens strains from clinical samples. In this report, we provide the first genomic analysis of P. fluorescens strains in which human vs. environmental isolates are compared. Seven P. fluorescens strains were isolated from respiratory samples from cystic fibrosis (CF) patients. The clinical strains could grow at a higher temperature (>34 °C) than has been reported for environmental strains. Draft genomes were generated for all of the clinical strains, and multi-locus sequence analysis placed them within subclade III of the P. fluorescens species-complex. All strains encoded type- II, -III, -IV, and -VI secretion systems, as well as the widespread colonization island (WCI). This is the first description of a WCI in P. fluorescens strains. All strains also encoded a complete I2/PfiT locus and showed evidence of horizontal gene transfer. The clinical strains were found to differ from the environmental strains in the number of genes involved in metal resistance, which may be a possible adaptation to chronic antibiotic exposure in the CF lung. This is the largest comparative genomics analysis of P. fluorescens subclade III strains to date and includes the first clinical isolates. At a global level, the clinical P. fluorescens subclade III strains were largely indistinguishable from environmental P. fluorescens subclade III strains, supporting the idea that identifying strains as 'environmental' vs 'clinical' is not a phenotypic trait. Rather, strains within P. fluorescens subclade III will colonize and persist in any niche that provides the requirements necessary for growth.

  13. ANOMALOUS BLUE COLOURING OF MOZZARELLA CHEESE INTENTIONALLY CONTAMINATED WITH PIGMENT PRODUCING STRAINS OF PSEUDOMONAS FLUORESCENS

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    P. Sechi

    2011-04-01

    Full Text Available In summer 2010 a large outbreak of anomalous blue coloration of mozzarella cheese was recorded in Italy and some northern European countries. Official laboratory analysis and health authorities linked the outbreak to the contamination of processing water with strains of Pseudomonas fluorescens, although several expert raised the question of how to unequivocally link the blue coloring to the presence of the micro-organism. In an attempt to set-up a method to determine whether a given Pseudomonas spp. strain is responsible of the defect, an in vitro system for the evaluation of blue colouring of mozzarella cheese intentionally contaminated with strains of Pseudomonas fluorescens. was developed The system is aimed to ascertain whether P. fluorescens strains, isolated from mozzarella cheese with anomalous blue coloration, are able to reproduce the blue coloration under controlled experimental condition. 96 trials of experimental inoculation of mozzarella cheese in different preservation liquids, were conducted using various suspension of Pseudomonas spp. (P. fluorescens ATCC 13525, P. fluorescens CFBP 3150, one P. fluorescens field strain isolated from blue-colored mozzarella cheese and P. aeruginosa ATCC 10145 as positive control at different concentrations and incubated at different temperatures. Growth curve of all Pseudomonas spp. strains tested demonstrated that after three days of incubation the concentration was generally higher than 106 CFU/g of mozzarella cheese incubated in Tryptic Soy Broth (TSB, and higher than 105 CFU/g of mozzarella cheese incubated in preservation liquid. All mozzarella cheeses inoculated with the field strain of Pseudomonas fluorescens showed the characteristic anomalous blue coloration, which is often associated with Pseudomonas fluorescens contamination of water used during mozzarella cheesemaking. With the proposed system, which enabled a considerable amount of samples to be analysed under controlled experimental

  14. Control of Fusarium verticillioides, cause of ear rot of maize, by Pseudomonas fluorescens

    DEFF Research Database (Denmark)

    Nayaka, Siddaiah Chandra; Shankar, Akarere C. Udaya; Reddy, Munagala S.

    2009-01-01

    and the formulations, in comparison with the control, increased plant growth and vigour as measured by seed germination, seedling vigour, plant height, 1000 seed weight and yield. P. fluorescens pure culture used as seed treatment and as spray treatment enhanced the growth parameters and reduced the incidence of F...... elicited considerable attention over the past decade owing to their association with animal disease syndromes. Hence, the present study was conducted to evaluate ecofriendly approaches by using a maize rhizosphere isolate of Pseudomonas fluorescens (Trev.) Mig. and its formulation to control ear rot....... The field trials included both seed treatment and foliar spray. For all the experiments, P. fluorescens was formulated using corn starch, wheat bran and talc powder. In each case there were three different treatments of P. fluorescens, a non-treated control and chemical control. RESULTS: Pure culture...

  15. 40 CFR 180.1114 - Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae 742RS; exemptions from the requirement of a tolerance... Tolerances § 180.1114 Pseudomonas fluorescens A506, Pseudomonas fluorescens 1629RS, and Pseudomonas syringae...

  16. Mutation Rate, Spectrum, Topology, and Context-Dependency in the DNA Mismatch Repair-Deficient Pseudomonas fluorescens ATCC948

    OpenAIRE

    Long, Hongan; Sung, Way; Miller, Samuel F.; Ackerman, Matthew S.; Doak, Thomas G.; Lynch, Michael

    2014-01-01

    High levels of genetic diversity exist among natural isolates of the bacterium Pseudomonas fluorescens, and are especially elevated around the replication terminus of the genome, where strain-specific genes are found. In an effort to understand the role of genetic variation in the evolution of Pseudomonas, we analyzed 31,106 base substitutions from 45 mutation accumulation lines of P. fluorescens ATCC948, naturally deficient for mismatch repair, yielding a base-substitution mutation rate of 2...

  17. Contribution of the Pseudomonas fluorescens MFE01 Type VI Secretion System to Biofilm Formation.

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    Mathias Gallique

    Full Text Available Type VI secretion systems (T6SSs are widespread in Gram-negative bacteria, including Pseudomonas. These macromolecular machineries inject toxins directly into prokaryotic or eukaryotic prey cells. Hcp proteins are structural components of the extracellular part of this machinery. We recently reported that MFE01, an avirulent strain of Pseudomonas fluorescens, possesses at least two hcp genes, hcp1 and hcp2, encoding proteins playing important roles in interbacterial interactions. Indeed, P. fluorescens MFE01 can immobilise and kill diverse bacteria of various origins through the action of the Hcp1 or Hcp2 proteins of the T6SS. We show here that another Hcp protein, Hcp3, is involved in killing prey cells during co-culture on solid medium. Even after the mutation of hcp1, hcp2, or hcp3, MFE01 impaired biofilm formation by MFP05, a P. fluorescens strain isolated from human skin. These mutations did not reduce P. fluorescens MFE01 biofilm formation, but the three Hcp proteins were required for the completion of biofilm maturation. Moreover, a mutant with a disruption of one of the unique core component genes, MFE01ΔtssC, was unable to produce its own biofilm or inhibit MFP05 biofilm formation. Finally, MFE01 did not produce detectable N-acyl-homoserine lactones for quorum sensing, a phenomenon reported for many other P. fluorescens strains. Our results suggest a role for the T6SS in communication between bacterial cells, in this strain, under biofilm conditions.

  18. Pseudomonas fluorescens in dairy products: a new case of blue mozzarella in Sardinia region

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    Chiara Nogarol

    2013-02-01

    Full Text Available Following a case of blue mozzarella occurred in Sardinia region, 14 isolates of Pseudomonas fluorescens have been isolated. Data analysis of pulsed-field-gel-electrophoresis profiles allowed to divide the isolates in two different clades, genetically unrelated. The presence of these two strains, deriving from nearby productions, confirmed the high diffusion of this microorganism. Multiples contamination sources (raw materials, processing surfaces and water supply made this specie one of the most relevant of the dairy productions chain.

  19. Whole-genome sequence of Pseudomonas fluorescens EK007-RG4, a promising biocontrol agent against a broad range of bacteria, including the fire blight bacterium Erwinia amylovora

    DEFF Research Database (Denmark)

    Habibi, Roghayeh; Tarighi, Saeed; Behravan, Javad

    2017-01-01

    Here, we report the first draft whole-genome sequence of Pseudomonas fluorescens strain EK007-RG4, which was isolated from the phylloplane of a pear tree. P. fluorescens EK007-RG4 displays strong antagonism against Erwinia amylovora, the causal agent for fire blight disease, in addition to several...

  20. Assessment of DAPG-producing Pseudomonas fluorescens for management of Meloidogyne incognita and Fusarium oxysporum on watermelon

    Science.gov (United States)

    Pseudomonas fluorescens isolates Clinto 1R, Wayne 1R and Wood 1R, which produce the antibiotic 2,4-diacetylphloroglucinol (DAPG), can suppress soilborne diseases and promote plant growth. Consequently, these beneficial bacterial isolates were tested on watermelon plants for suppression of Meloidogy...

  1. Identification and Characterization of the emhABC Efflux System for Polycyclic Aromatic Hydrocarbons in Pseudomonas fluorescens cLP6a

    OpenAIRE

    Hearn, Elizabeth M.; Dennis, Jonathan J.; Gray, Murray R.; Foght, Julia M.

    2003-01-01

    The hydrocarbon-degrading environmental isolate Pseudomonas fluorescens LP6a possesses an active efflux mechanism for the polycyclic aromatic hydrocarbons phenanthrene, anthracene, and fluoranthene but not for naphthalene or toluene. PCR was used to detect efflux pump genes belonging to the resistance-nodulation-cell division (RND) superfamily in a plasmid-cured derivative, P. fluorescens cLP6a, which is unable to metabolize hydrocarbons. One RND pump, whose gene was identified in P. fluoresc...

  2. Rhizobacteria Pseudomonas fluorescens and Azospirillum sp. association enhances growth of Lactuca sativa L. under tropical conditions

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    Amael APONTE

    2017-06-01

    Full Text Available The selection of microorganisms that enhance plant growth and confer biotic and abiotic tolerance to crops constitutes a biotechnology currently gaining importance on a global scale. The aim of this investigation was to evaluate the effects of inoculating rhizobacteria to lettuce (Lactuca sativa L. on seed germination and vegetative development in order to use isolates as potential biofertilizers under tropical conditions. Five isolates of Pseudomonas fluorescens (Pf and one of Azospirillum sp. (Az were inoculated to seeds using a bacterial suspension of 1.5*108 CFU*mL-1. In vitro, none of the isolates promoted germination. In vivo, isolates promoted growth and acted as stress alleviators by conferring tolerance to high temperatures (≥ 30 °C. The highest seedling emergence percentages were induced by the association of P.fluorescens with Azospirillum. This association also promoted the highest leaf-area in 25 d seedlings and exhibited a significantly higher dry-weight in 40 d plants compared to the control (P≤0.05 supporting the advantages of bio-consortiums over individual strains. The strains were able to produce dependent L-tryptophan indole-3-acetic acid (IAA, to solubilize phosphorous in vitro and tolerated at least 5%-salt stress. The results indicate that isolate Pf (26 and Az possess plant growth promoting rhizobacteria (PGPR traits and should be further assessed. This study suggests that P. fluorescens and Azospirillum act synergically and are able to trigger an induced-tolerance mechanism in lettuce under abiotic stress.

  3. Growth of Pseudomonas fluorescens on Cassava Starch ...

    African Journals Online (AJOL)

    The potential of local strains of microorganism (Pseudomonas fluorescens) in polyhydroxbutyrate production was investigated in this study. This was with a view to establishing the capabilities of local strains of microorganisms on utilizing renewable and locally available substrates in polyhydroxybutyrate production.

  4. Characterization and identification of Pseudomonas fluorescens ...

    African Journals Online (AJOL)

    Crystal violet (CV), a recalcitrant molecule, used commonly as biological stain and commercial dye, was subjected to biodegradation in this study by Pseudomonas fluorescens NCIM 2100 and its biodegraded metabolic products were identified by UV, 1HNMR and IR Spectrophotometry. During degradation process CV dye ...

  5. Pseudomonas fluorescens biofilms subjected to phage phiIBB-PF7A

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    Neubauer Peter

    2008-10-01

    Full Text Available Abstract Background Pseudomonas fluorescens is an important food spoilage organism, usually found in the form of biofilms. Bacterial biofilms are inherently resistant to a variety of antimicrobial agents, therefore alternative methods to biofilm control, such as bacteriophages (phages have been suggested. Phage behavior on biofilms is still poorly investigated and needs further understanding. Here we describe the application of phage ϕIBB-PF7, a newly isolated phage, to control P. fluorescens biofilms. The biofilms were formed under static or dynamic conditions and with or without renewal of medium. Results Conditions for biofilm formation influenced the feature of the biofilm and the morphology of P. fluorescens. Biomass removal due to phage activity varied between 63 and 91% depending on the biofilm age and the conditions under which the biofilm had been formed and phages applied. Removal of the biofilm by phage treatment was faster in younger biofilms, but the same number of surviving cells was detected in all tested biofilms, after only 4 h of treatment, even in older biofilms. Under static conditions, a 3 log higher number of phage progeny remained either inside the biofilm matrix or attached to the substratum surface than under dynamic conditions, pointing to the importance of experimental conditions for the efficacy of phage entrapment into the biofilm. Conclusion Phage ϕIBB-PF7A is highly efficient in removing P. fluorescens biofilms within a short time interval. The conditions of biofilm formation and applied during phage infection are critical for the efficacy of the sanitation process. The integration of phages into the biofilm matrix and their entrapment to the surface may be further beneficial factors when phage treatment is considered alone or in addition to chemical biocides in industrial environments where P. fluorescens causes serious spoilage.

  6. Genetic Control of Plant Root Colonization by the Biocontrol agent, Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Benjamin J.; Fletcher, Meghan; Waters, Jordan; Wetmore, Kelly; Blow, Matthew J.; Deutschbauer, Adam M.; Dangl, Jeffry L.; Visel, Axel

    2015-03-19

    Plant growth promoting rhizobacteria (PGPR) are a critical component of plant root ecosystems. PGPR promote plant growth by solubilizing inaccessible minerals, suppressing pathogenic microorganisms in the soil, and directly stimulating growth through hormone synthesis. Pseudomonas fluorescens is a well-established PGPR isolated from wheat roots that can also colonize the root system of the model plant, Arabidopsis thaliana. We have created barcoded transposon insertion mutant libraries suitable for genome-wide transposon-mediated mutagenesis followed by sequencing (TnSeq). These libraries consist of over 105 independent insertions, collectively providing loss-of-function mutants for nearly all genes in the P.fluorescens genome. Each insertion mutant can be unambiguously identified by a randomized 20 nucleotide sequence (barcode) engineered into the transposon sequence. We used these libraries in a gnotobiotic assay to examine the colonization ability of P.fluorescens on A.thaliana roots. Taking advantage of the ability to distinguish individual colonization events using barcode sequences, we assessed the timing and microbial concentration dependence of colonization of the rhizoplane niche. These data provide direct insight into the dynamics of plant root colonization in an in vivo system and define baseline parameters for the systematic identification of the bacterial genes and molecular pathways using TnSeq assays. Having determined parameters that facilitate potential colonization of roots by thousands of independent insertion mutants in a single assay, we are currently establishing a genome-wide functional map of genes required for root colonization in P.fluorescens. Importantly, the approach developed and optimized here for P.fluorescens>A.thaliana colonization will be applicable to a wide range of plant-microbe interactions, including biofuel feedstock plants and microbes known or hypothesized to impact on biofuel-relevant traits including biomass productivity

  7. Interaction of the psychrotroph Pseudomonas fluorescens In5 with phytopathogens in cold soils

    DEFF Research Database (Denmark)

    Hennessy, Rosanna Catherine; Olsson, Stefan; Stougaard, Peter

    Aim: Potato cultivation in southwest Greenland, at Inneruulalik, omits the use of pesticides while relying on limited crop rotations and despite the presence of plant pathogens in the soil does not suffer from major disease outbreaks. Previously, we have shown that the soil at Inneruulalik...... is disease suppressive owing to the presence of diverse antimicrobial microorganisms. Using culture-based approaches, the psychrotroph Pseudomonas fluorescens In5 was previously isolated from the soil microbiome. The aim of this study is to unravel key biocontrol traits underpinning the antagonistic activity...... of this cold-active bacterium against phytopathogens. Method: A combination of different technologies including genomics, transcriptomics and metabolomics are being used to explore the interaction of the psychrotroph P. fluorescens In5 in dual-culture with diverse plant pathogens. To date, molecular genetics...

  8. Pseudomonas fluorescens strain CL145A - a biopesticide for the control of zebra and quagga mussels (Bivalvia: Dreissenidae).

    Science.gov (United States)

    Molloy, Daniel P; Mayer, Denise A; Gaylo, Michael J; Morse, John T; Presti, Kathleen T; Sawyko, Paul M; Karatayev, Alexander Y; Burlakova, Lyubov E; Laruelle, Franck; Nishikawa, Kimi C; Griffin, Barbara H

    2013-05-01

    Zebra mussels (Dreissena polymorpha) and quagga mussels (Dreissena rostriformis bugensis) are the "poster children" of high-impact aquatic invasive species. In an effort to develop an effective and environmentally acceptable method to control their fouling of raw-water conduits, we have investigated the potential use of bacteria and their natural metabolic products as selective biological control agents. An outcome of this effort was the discovery of Pseudomonas fluorescens strain CL145A - an environmental isolate that kills these dreissenid mussels by intoxication (i.e., not infection). In the present paper, we use molecular methods to reconfirm that CL145A is a strain of the species P. fluorescens, and provide a phylogenetic analysis of the strain in relation to other Pseudomonas spp. We also provide evidence that the natural product lethal to dreissenids is associated with the cell wall of P. fluorescens CL145A, is a heat-labile secondary metabolite, and has degradable toxicity within 24 h when applied to water. CL145A appears to be an unusual strain of P. fluorescens since it was the only one among the ten strains tested to cause high mussel mortality. Pipe trials conducted under once-through conditions indicated: (1) P. fluorescens CL145A cells were efficacious against both zebra and quagga mussels, with high mortalities achieved against both species, and (2) as long as the total quantity of bacterial cells applied during the entire treatment period was the same, similar mussel mortality could be achieved in treatments lasting 1.5-12.0 h, with longer treatment durations achieving lower mortalities. The efficacy data presented herein, in combination with prior demonstration of its low risk of non-target impact, indicate that P. fluorescens CL145A cells have significant promise as an effective and environmentally safe control agent against these invasive mussels. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Pseudomonas putida and Pseudomonas fluorescens Species Group Recovery from Human Homes Varies Seasonally and by Environment.

    Directory of Open Access Journals (Sweden)

    Susanna K Remold

    Full Text Available By shedding light on variation in time as well as in space, long-term biogeographic studies can help us define organisms' distribution patterns and understand their underlying drivers. Here we examine distributions of Pseudomonas in and around 15 human homes, focusing on the P. putida and P. fluorescens species groups. We describe recovery from 10,941 samples collected during up to 8 visits per home, occurring on average 2.6 times per year. We collected a mean of 141 samples per visit, from sites in most rooms of the house, from the surrounding yards, and from human and pet occupants. We recovered Pseudomonas in 9.7% of samples, with the majority of isolates being from the P. putida and P. fluorescens species groups (approximately 62% and 23% of Pseudomonas samples recovered respectively. Although representatives of both groups were recovered from every season, every house, and every type of environment sampled, recovery was highly variable across houses and samplings. Whereas recovery of P. putida group was higher in summer and fall than in winter and spring, P. fluorescens group isolates were most often recovered in spring. P. putida group recovery from soils was substantially higher than its recovery from all other environment types, while higher P. fluorescens group recovery from soils than from other sites was much less pronounced. Both species groups were recovered from skin and upper respiratory tract samples from healthy humans and pets, although this occurred infrequently. This study indicates that even species that are able to survive under a broad range of conditions can be rare and variable in their distributions in space and in time. For such groups, determining patterns and causes of stochastic and seasonal variability may be more important for understanding the processes driving their biogeography than the identity of the types of environments in which they can be found.

  10. Pseudomonas putida and Pseudomonas fluorescens Species Group Recovery from Human Homes Varies Seasonally and by Environment.

    Science.gov (United States)

    Remold, Susanna K; Purdy-Gibson, Megan E; France, Michael T; Hundley, Thomas C

    2015-01-01

    By shedding light on variation in time as well as in space, long-term biogeographic studies can help us define organisms' distribution patterns and understand their underlying drivers. Here we examine distributions of Pseudomonas in and around 15 human homes, focusing on the P. putida and P. fluorescens species groups. We describe recovery from 10,941 samples collected during up to 8 visits per home, occurring on average 2.6 times per year. We collected a mean of 141 samples per visit, from sites in most rooms of the house, from the surrounding yards, and from human and pet occupants. We recovered Pseudomonas in 9.7% of samples, with the majority of isolates being from the P. putida and P. fluorescens species groups (approximately 62% and 23% of Pseudomonas samples recovered respectively). Although representatives of both groups were recovered from every season, every house, and every type of environment sampled, recovery was highly variable across houses and samplings. Whereas recovery of P. putida group was higher in summer and fall than in winter and spring, P. fluorescens group isolates were most often recovered in spring. P. putida group recovery from soils was substantially higher than its recovery from all other environment types, while higher P. fluorescens group recovery from soils than from other sites was much less pronounced. Both species groups were recovered from skin and upper respiratory tract samples from healthy humans and pets, although this occurred infrequently. This study indicates that even species that are able to survive under a broad range of conditions can be rare and variable in their distributions in space and in time. For such groups, determining patterns and causes of stochastic and seasonal variability may be more important for understanding the processes driving their biogeography than the identity of the types of environments in which they can be found.

  11. Antimicrobial activity of four essential oils against pigmenting Pseudomonas fluorescens and biofilmproducing Staphylococcus aureus of dairy origin

    Directory of Open Access Journals (Sweden)

    Francesca Pedonese

    2017-12-01

    Full Text Available Essential oils (EOs are mixtures of secondary metabolites of plant origin with many useful properties, among which the antimicrobial activity is also of interest for the food industry. EOs can exert their antimicrobial potential both directly, in food products and active packaging, and indirectly, as sanitizing and anti-biofilm agents of food facility surfaces. Aim of this research was to evaluate the antimicrobial activity of four EOs (bergamot, cinnamon, manuka and thyme against Pseudomonas fluorescens and Staphylococcus aureus isolated from milk and dairy products. The chemical composition of EOs was evaluated by Gas Chromatography-Mass Spectrometry analysis. Minimum Inhibitory Concentration values were determined by a microplate method against 9 Ps. fluorescens from marketed mozzarella with blue discoloration defect, and 3 biofilm-producing S. aureus from milk. Reference ATCC strains were included. Pigment production activity by Ps. fluorescens was assessed both in culture and in cheese. EOs of manuka (leptospermone 23% and thyme (carvacrol 30%, pcymene 20%, thymol 15% showed the highest antimicrobial activity against S. aureus, MIC values were 0.012%-0.024% and 0.024% v/v, respectively; meanwhile EOs from thyme and cinnamon (cinnamaldehyde 55% exhibited the best activity against Ps. fluorescens with MIC values of 0.098%-0.195% and 0.195%-0.391% v/v, respectively. The antimicrobial activity of these EOs is promising and they could be exploited in the dairy production chain.

  12. Antimicrobial activity of four essential oils against pigmenting Pseudomonas fluorescens and biofilmproducing Staphylococcus aureus of dairy origin

    Science.gov (United States)

    Pedonese, Francesca; Fratini, Filippo; Pistelli, Luisa; Porta, Federica Maria; Ciccio, Pierluigi Di; Fischetti, Roberto; Turchi, Barbara; Nuvoloni, Roberta

    2017-01-01

    Essential oils (EOs) are mixtures of secondary metabolites of plant origin with many useful properties, among which the antimicrobial activity is also of interest for the food industry. EOs can exert their antimicrobial potential both directly, in food products and active packaging, and indirectly, as sanitizing and anti-biofilm agents of food facility surfaces. Aim of this research was to evaluate the antimicrobial activity of four EOs (bergamot, cinnamon, manuka and thyme) against Pseudomonas fluorescens and Staphylococcus aureus isolated from milk and dairy products. The chemical composition of EOs was evaluated by Gas Chromatography-Mass Spectrometry analysis. Minimum Inhibitory Concentration values were determined by a microplate method against 9 Ps. fluorescens from marketed mozzarella with blue discoloration defect, and 3 biofilm-producing S. aureus from milk. Reference ATCC strains were included. Pigment production activity by Ps. fluorescens was assessed both in culture and in cheese. EOs of manuka (leptospermone 23%) and thyme (carvacrol 30%, pcymene 20%, thymol 15%) showed the highest antimicrobial activity against S. aureus, MIC values were 0.012%-0.024% and 0.024% v/v, respectively; meanwhile EOs from thyme and cinnamon (cinnamaldehyde 55%) exhibited the best activity against Ps. fluorescens with MIC values of 0.098%-0.195% and 0.195%-0.391% v/v, respectively. The antimicrobial activity of these EOs is promising and they could be exploited in the dairy production chain. PMID:29564238

  13. When cheese gets the blues: Pseudomonas fluorescens as the causative agent of cheese spoilage.

    Science.gov (United States)

    Martin, N H; Murphy, S C; Ralyea, R D; Wiedmann, M; Boor, K J

    2011-06-01

    A bacterial contamination of fresh, low-acid cheese that resulted in production of a blue fluorescent pigment on the surface of the cheese was determined to be caused by Pseudomonas fluorescens biovar IV, a gram-negative bacteria that produces a blue, nondiffusible pigment as well as the soluble pigment pyoverdin, which fluoresces under UV light. Ten isolates collected from contaminated cheese and environmental samples were initially identified as P. fluorescens using 16S rDNA sequencing, but only 8 of the isolates produced blue pigment and fluoresced under UV light when re-inoculated onto fresh, low-acid cheese. The Biolog Metabolic Fingerprint system (Biolog Inc., Hayward, CA) and the Analytical Profile Index (BioMerieux Vitek Inc., Hazelwood, MO) for nonenteric gram-negative species as well as EcoRI ribotyping did not differentiate between the isolates that produced blue color and those that did not. Pulsed field gel electrophoresis with the enzyme XbaI was able to distinguish between the isolates that produced pigment and those that did not and allowed for identification of a specific environmental site (i.e., an overhead cheese vat agitator system) as the likely source of product contamination. Copyright © 2011 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  14. Biosynthesis and regulation of cyclic lipopeptides in Pseudomonas fluorescens

    OpenAIRE

    Bruijn, de, I.

    2009-01-01

    Cyclic lipopeptides (CLPs) are surfactant and antibiotic metabolites produced by a variety of bacterial genera. For the genus Pseudomonas, many structurally different CLPs have been identified. CLPs play an important role in surface motility of Pseudomonas strains, but also in virulence and attachment/detachment to and from surfaces. In this Ph.D. thesis project, two new CLP biosynthesis clusters were identified in Pseudomonas fluorescens and fully sequenced. In P. fluorescens strain SBW2...

  15. Systematic investigations on the biodegradation and viscosity reduction of long chain hydrocarbons using Pseudomonas aeruginosa and Pseudomonas fluorescens.

    Science.gov (United States)

    Sakthipriya, N; Doble, Mukesh; Sangwai, Jitendra S

    2016-03-01

    The use of microorganisms has been researched extensively for possible applications related to hydrocarbon degradation in the petroleum industry. However, attempts to improve the effect of microorganisms on the viscosity of hydrocarbons, which find potential use in the development of robust models for biodegradation, have been rarely documented. This study investigates the degradation of long chain hydrocarbons, such as hexadecane and eicosane using Pseudomonas fluorescens PMMD3 (P. fluorescens) and Pseudomonas aeruginosa CPCL (P. aeruginosa). P. aeruginosa used here is isolated from petroleum contaminated sediments and the P. fluorescens is from the coastal area, and both have hydrocarbon degrading genes. The degradation of hydrocarbons is studied using carbon profiling and reduction in viscosity pre- and post-degradation of hydrocarbons. The carbon profiling has been obtained using gas chromatography-mass spectroscopy (GC-MS), and Fourier transform infrared spectrometer (FTIR) results. GC-MS results have indicated an improved biodegradation of hydrocarbons by 77-93% in one day. The yield coefficients of biomass (YX/S) for P. aeruginosa and P. fluorescens using hexadecane as a carbon source are 1.35 and 0.81 g g(-1), and the corresponding values with eicosane are 0.84 and 0.88 g g(-1). The viscosity of hexadecane is reduced by the order of 53 and 47%, while that of eicosane was reduced by 53 and 65%, using P. aeruginosa and P. fluorescens, respectively. This study also presents information on the activity of enzymes responsible for the hydrocarbon degradation. Pseudomonas species have shown their use in potential applications for bioremediation, oil-spill treatment, and flow assurance. We believe that this study will also provide stringent tests for possible model development for the bioremediation of long chain paraffins suitable for oilfield applications.

  16. Draft Genome Sequences of Pseudomonas fluorescens BS2 and Pusillimonas noertemannii BS8, Soil Bacteria That Cooperate To Degrade the Poly- -D-Glutamic Acid Anthrax Capsule

    KAUST Repository

    Stabler, R. A.

    2013-01-24

    A mixed culture of Pseudomonas fluorescens BS2 and Pusillimonas noertemannii BS8 degraded poly-γ-d-glutamic acid; when the 2 strains were cultured separately, no hydrolytic activity was apparent. Here we report the draft genome sequences of both soil isolates.

  17. Structure Revision of N-Mercapto-4-formylcarbostyril Produced by Pseudomonas fluorescens G308 to 2-(2-Hydroxyphenyl)thiazole-4-carbaldehyde [aeruginaldehyde

    DEFF Research Database (Denmark)

    Guillemyn, Karel; Ballet, Steven; Ye, Lumeng

    2014-01-01

    An antibiotic substance isolated from Pseudomonas fluorescens strain G308 was earlier assigned the structure of N-mercapto-4-formylcarbostyril, but computational predictions of the H-1 and C-13 NMR magnetic shielding tensors show this structure to be incompatible with the published spectroscopic ...

  18. Uji Lapangan Formula Cair Pseudomonas fluorescens P60 terhadap Layu Fusarium pada Tanaman Tomat

    Directory of Open Access Journals (Sweden)

    Loekas Soesanto

    2011-12-01

    Full Text Available A research aimed at knowing 1 the effect of Pseudomonas fluorescens P60 in liquid formula on Fusarium wilt of tomato, 2 the effect of P. fluorescens P60 in the formula on tomato growth and yield, and 3 P. fluorescens P60 mechanisms on tomata was carried out at tomato field of Selomoyo Village, Kaliangkrik Subdistrict, Magelang Regency at altitude of 826 m above sea level. Randomized block design was used with seven treatments and four replicates. The treatments were control, with P. fluorescens P60 soaked for 15 min and without fungicide, pathogen without P. fluorescens P60 with fungicide (PBG1, pathogen with P. fluorescens P60 without fungicide, pathogen with pouring P. fluorescens P60 1, 3, and 5 times. Result indicated that application of formulated P. fluorescens P60 for 5 times decreased the disease intensity as high as 26.77%, and late population of the pathogen but increased P. fluorescens P60 as high as 4.54×1010 cfu ml-1. P. fluorescens P60 affected growth and yield of tomato. P. Fluorescens P60 induced tomato resistance by increasing qualitatively its phenolic compound content (saponin, tannin, glycoside.   Penelitian dengan tujuan untuk mengetahui: 1 pengaruh Pseudomonas fluorescens P60 dalam formula cair terhadap penyakit layu fusarium pada tanaman tomat, 2 pengaruh P. fluorescens P60 dalam formula cair terhadap pertumbuhan dan produksi tanaman tomat, dan 3 mekanisme P. fluorescens P60 pada tanaman tomat dilakukan di lahan Desa Selomoyo, Kecamatan Kaliangkrik, Kabupaten Magelang dengan ketinggian 826 m di atas permukaan laut. Penelitian menggunakan Rancangan Acak Kelompok (RAK, dengan 7 perlakuan dan jumlah ulangan 4 kali, dan setiap unit terdiri atas 8 tanaman. Perlakuan tersebut meliputi kontrol; dengan P. fluorescens P60 rendam 15 menit dan tanpa fungisida; dengan patogen; tanpa P. fluorescens P60; dengan fungisida (PBG1; patogen, tanpa P. fluorescens P60, tanpa fungisida; patogen, dengan penyiraman P. fluorescens P60 1 kali

  19. Characterization of the biocontrol activity of pseudomonas fluorescens strain X reveals novel genes regulated by glucose.

    Directory of Open Access Journals (Sweden)

    Gerasimos F Kremmydas

    Full Text Available Pseudomonas fluorescens strain X, a bacterial isolate from the rhizosphere of bean seedlings, has the ability to suppress damping-off caused by the oomycete Pythium ultimum. To determine the genes controlling the biocontrol activity of strain X, transposon mutagenesis, sequencing and complementation was performed. Results indicate that, biocontrol ability of this isolate is attributed to gcd gene encoding glucose dehydrogenase, genes encoding its co-enzyme pyrroloquinoline quinone (PQQ, and two genes (sup5 and sup6 which seem to be organized in a putative operon. This operon (named supX consists of five genes, one of which encodes a non-ribosomal peptide synthase. A unique binding site for a GntR-type transcriptional factor is localized upstream of the supX putative operon. Synteny comparison of the genes in supX revealed that they are common in the genus Pseudomonas, but with a low degree of similarity. supX shows high similarity only to the mangotoxin operon of Ps. syringae pv. syringae UMAF0158. Quantitative real-time PCR analysis indicated that transcription of supX is strongly reduced in the gcd and PQQ-minus mutants of Ps. fluorescens strain X. On the contrary, transcription of supX in the wild type is enhanced by glucose and transcription levels that appear to be higher during the stationary phase. Gcd, which uses PQQ as a cofactor, catalyses the oxidation of glucose to gluconic acid, which controls the activity of the GntR family of transcriptional factors. The genes in the supX putative operon have not been implicated before in the biocontrol of plant pathogens by pseudomonads. They are involved in the biosynthesis of an antimicrobial compound by Ps. fluorescens strain X and their transcription is controlled by glucose, possibly through the activity of a GntR-type transcriptional factor binding upstream of this putative operon.

  20. Multistate outbreak of Pseudomonas fluorescens bloodstream infection after exposure to contaminated heparinized saline flush prepared by a compounding pharmacy.

    Science.gov (United States)

    Gershman, Mark D; Kennedy, Donald J; Noble-Wang, Judith; Kim, Curi; Gullion, Jessica; Kacica, Marilyn; Jensen, Bette; Pascoe, Neil; Saiman, Lisa; McHale, Jean; Wilkins, Melinda; Schoonmaker-Bopp, Dianna; Clayton, Joshua; Arduino, Matthew; Srinivasan, Arjun

    2008-12-01

    Pharmaceutical compounding, the manipulation of ingredients to create a customized medication, is a widespread practice. In January 2005, the Centers for Disease Control and Prevention was notified of 4 cases of Pseudomonas fluorescens bacteremia that were traced to contaminated heparinized saline intravenous flush syringes prepared as a compounded medical product. We reviewed medical records of symptomatic patients with P. fluorescens-positive cultures of blood specimens or sections of explanted catheters, reviewed the production process of syringes, performed syringe cultures, compared isolates by pulsed-field gel electrophoresis (PFGE), and examined catheters by scanning electron microscopy. We identified 80 patients in 6 states with P. fluorescens-positive cultures during December 2004-March 2006. Sixty-four patients (80%) had received a diagnosis of cancer. Seventy-four (99%) of 75 patients for whom information about catheter type was available had long-term indwelling catheters. Thirty-three (41%) of 80 cases were diagnosed 84-421 days after the patient's last potential exposure to a contaminated flush (delayed-onset cases). Compared with patients with early infection onset, more patients with delayed infection onset had venous ports (100% versus 50%; P <.001). By PFGE, clinical isolates from 50 (98%) of 51 patients were related to isolates cultured from unopened syringes. Scanning electron microscopy of explanted catheters revealed biofilms containing organisms morphologically consistent with P. fluorescens. This outbreak underscores important challenges in ensuring the safety of compounded pharmaceuticals and demonstrates the potential for substantially delayed infections after exposures to contaminated infusates. Exposures to compounded products should be considered when investigating outbreaks. Patients exposed to contaminated infusates require careful follow-up, because infections can occur long after exposure.

  1. Distribution of a Take-All Suppressive Strain of Pseudomonas fluorescens on Seminal Roots of Winter Wheat.

    Science.gov (United States)

    Weller, D M

    1984-10-01

    An antibiotic-resistant strain of Pseudomonas fluorescens, that suppresses take-all of wheat, was used to study the distribution of the bacteria on seminal roots of wheat after being introduced onto seeds. Cells of P. fluorescens were isolated from the entire length of the root, and density of the introduced bacteria declined with the distance from the base of the root. Maximum populations of 10 to 10 CFU and 10 to 10 CFU per cm of root were detected on sections of roots near the seed and root tip, respectively. The introduced bacteria competed well with indigenous bacteria, comprising at least 25% of the fluorescent pseudomonads detected by plate counts for 48 days after planting.

  2. Lethality and Developmental Delay of Drosophila melanogaster Following Ingestion of Selected Pseudomonas fluorescens Strains

    Science.gov (United States)

    Pseudomonas fluorescens secretes antimicrobial compounds that promote plant health and provide protection from pathogens. We used a non-invasive feeding assay to study the toxicity of P. fluorescens strains Pf0-1, SBW25, and Pf-5 to Drosophila melanogaster. The three strains of P. fluorescens varie...

  3. Supervivencia de Pseudomonas fluorescens en suelos con diferente contenido de materia orgánica Pseudomonas fluorescens survival in soils with different contents of organic matter

    Directory of Open Access Journals (Sweden)

    E.B.R. Perotti

    2005-06-01

    Full Text Available Pseudomonas fluorescens es una bacteria PGPR (plant growth promoting rhizobacteria, heterótrofa, capaz de combatir fitopatógenos edáficos. Su supervivencia podría estar favorecida por el elevado contenido de materia orgánica del suelo (MOS. Para probarlo, se inocularon, en condiciones de laboratorio, tres cepas de P. fluorescens: UP61, C7R12, y P190 (nativa de Balcarce, Buenos Aires en suelos rizosféricos de tomate representativos de diferentes zonas de Argentina: suelo Argiudol (Balcarce, y Zavalla, Santa Fe y suelo Torrifluvens (Cipolletti, Río Negro (MOS %: 7,2; 4,3 y 2,6 respectivamente. Los resultados indicaron que la supervivencia de P. fluorescens en los suelos Argiudoles fue similar; aunque las pendientes de las curvas de supervivencia en el suelo de Zavalla fueron menores que las observadas en el suelo de Balcarce. La producción de CO2 fue superior en el suelo de Balcarce que en el suelo de Zavalla (4,3 y 2,8 mmol.g-1suelo, esta diferencia podría ser explicada por la existencia de una mayor presión competitiva por parte de la microflora nativa. La supervivencia en el suelo Torrifluvens resultó mínima, lo que sería atribuible a su elevada conductividad eléctrica más que al menor contenido de MOS. La cepa UP61 presentó en todos los casos la mejor supervivencia.Pseudomonas fluorescens are plant growth promoting rhizobacteria (PGPR. The survival of this inoculated heterotrophic bacterium may be affected by soil organic matter content (SOM. To confirm this hypothesis, three strains of P. fluorescens: UP61, C7R12 y P190 (native of Balcarce, Buenos Aires were inoculated, in laboratory conditions, into three argentine rhizospheric soils: two Argiudolls (Balcarce, and Zavalla, Santa Fe and a Torrifluvens (Cipolletti, Río Negro with different SOM: 7,2; 4,3; and 2,6%, respectibily. The results indicated that the all three isolates survival in general was not different. The slopes of the regression curves in Zavalla soil were very

  4. Pseudomonas fluorescens' view of the periodic table.

    Science.gov (United States)

    Workentine, Matthew L; Harrison, Joe J; Stenroos, Pernilla U; Ceri, Howard; Turner, Raymond J

    2008-01-01

    Growth in a biofilm modulates microbial metal susceptibility, sometimes increasing the ability of microorganisms to withstand toxic metal species by several orders of magnitude. In this study, a high-throughput metal toxicity screen was initiated with the aim of correlating biological toxicity data in planktonic and biofilm cells to the physiochemical properties of metal ions. To this end, Pseudomonas fluorescens ATCC 13525 was grown in the Calgary Biofilm Device (CBD) and biofilms and planktonic cells of this microorganism were exposed to gradient arrays of different metal ions. These arrays included 44 different metals with representative compounds that spanned every group of the periodic table (except for the halogens and noble gases). The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and minimum biofilm eradication concentration (MBEC) values were obtained after exposing the biofilms to metal ions for 4 h. Using these values, metal ion toxicity was correlated to the following ion-specific physicochemical parameters: standard reduction-oxidation potential, electronegativity, the solubility product of the corresponding metal-sulfide complex, the Pearson softness index, electron density and the covalent index. When the ions were grouped according to outer shell electron structure, we found that heavy metal ions gave the strongest correlations to these parameters and were more toxic on average than the other classes of the ions. Correlations were different for biofilms than for planktonic cells, indicating that chemical mechanisms of metal ion toxicity differ between the two modes of growth. We suggest that biofilms can specifically counter the toxic effects of certain physicochemical parameters, which may contribute to the increased ability of biofilms to withstand metal toxicity.

  5. Phytohormone production and colonization of canola (Brassica napus L.) roots by Pseudomonas fluorescens 6-8 under gnotobiotic conditions.

    Science.gov (United States)

    Pallai, Rajash; Hynes, Russell K; Verma, Brij; Nelson, Louise M

    2012-02-01

    Pseudomonas fluorescens 6-8, a rhizosphere isolate previously shown to enhance root elongation of canola ( Brassica napus L.), was characterized for its ability to produce indole-3-acetic acid and cytokinins in pure culture and in the rhizosphere of canola under gnotobiotic conditions in comparison with the cytokinin-producing strain P. fluorescens G20-18 and its mutant CNT2. Strain 6-8 produced isopentenyl adenosine, zeatin riboside, and dihydroxyzeatin riboside at levels similar to those of G20-18, but only very low concentrations of indole-3-acetic acid. In a gnotobiotic assay canola inoculated with 6-8 and G20-18 had higher concentrations of isopentenyl adenosine and zeatin riboside in the rhizosphere and greater root length than the noninoculated control. The ability of strain 6-8 to colonize canola roots was assessed following transformation with the green fluorescent protein and inoculation onto canola seed in a gnotobiotic assay. Higher populations of strain 6-8 were observed on the proximal region of the root closest to the seed than on the mid and distal portions 9 days after seed inoculation. The ability of P. fluorescens 6-8 to produce cytokinins, colonize the roots of canola seedlings, and enhance root elongation may contribute to its ability to survive in the rhizosphere and may benefit seedling growth.

  6. Pseudomonas fluorescens filamentous hemagglutinin, an iron-regulated protein, is an important virulence factor that modulates bacterial pathogenicity

    Directory of Open Access Journals (Sweden)

    Yuan-yuan Sun

    2016-08-01

    Full Text Available Pseudomonas fluorescens is a common bacterial pathogen to a wide range of aquaculture animals including various species of fish. In this study, we employed proteomic analysis and identified filamentous hemagglutinin (FHA as an iron-responsive protein secreted by TSS, a pathogenic P. fluorescens isolate. In vitro study showed that compared to the wild type, the fha mutant TSSfha (i exhibited a largely similar vegetative growth profile but significantly retarded in the ability of biofilm growth and producing extracellular matrix, (ii displayed no apparent flagella and motility, (iii was defective in the attachment to host cells and unable to form self-aggregation, (iv displayed markedly reduced capacity of hemagglutination and surviving in host serum. In vivo infection analysis revealed that TSSfha was significantly attenuated in the ability of dissemination in fish tissues and inducing host mortality, and that antibody blocking of the natural FHA produced by the wild type TSS impaired the infectivity of the pathogen. Furthermore, when introduced into turbot as a subunit vaccine, recombinant FHA elicited a significant protection against lethal TSS challenge. Taken together, these results indicate for the first time that P. fluorescens FHA is a key virulence factor essential to multiple biological processes associated with pathogenicity.

  7. Characterization of a Pseudomonas fluorescens strain from tomato rhizosphere and its use for integrated management of tomato damping-off

    Energy Technology Data Exchange (ETDEWEB)

    Jayaraj, J; Parthasarathi, T.; Radhakrishnan, N.V. [Annamalai University, Annamalainagar (India). Faculty of Agriculture

    2007-10-15

    A highly antagonistic Pseudomonas fluorescens strain was isolated from tomato rhizosphere and characterized for its in vitro and in vivo biocontrol potential against Pythium aphanidermatum. The identified Pseudomonas fluorescens strain (PfT-8) was capable of producing high levels of chitinase, beta-1,3-glucanase, cellulase, fungitoxic metabolites and siderophores. Seven different carrier formulations including a talc-based powder, lignite-based powder, peat-based powder, lignite + fly ash-based powder, wettable powder, bentonite-paste and polyethylene glycol (PEG) paste were prepared utilizing PfT-8. Shelf life was evaluated for up to 6 months of storage at ambient room temperature (28{sup o}C). Biocontrol efficacy of formulations was studied under greenhouse and field conditions. Among the formulations, peat, lignite, lignite+fly-ash and bentonite paste based formulations maintained higher propagule number than others and also showed greater biocontrol potential. However, propagule number gradually decreased with time. Soil incorporation of organic amendments and specifically poultry manure and FYM, significantly reduced damping-off incidence and also augmented the rhizosphere population of the marked P. fluorescens strain that was resistant to streptomycin and rifampicin.

  8. Listeria monocytogenes Impact on Mature or Old Pseudomonas fluorescens Biofilms During Growth at 4 and 20°C.

    Science.gov (United States)

    Puga, Carmen H; Orgaz, Belen; SanJose, Carmen

    2016-01-01

    Changes in spatial organization, as observed by confocal laser scanning microscopy (CLSM), viable cell content, biovolume, and substratum surface coverage of the biofilms formed on glass by Pseudomonas fluorescens resulting from co-culture with Listeria monocytogenes, were examined. Two strains of L. monocytogenes, two culture temperatures and two biofilm developmental stages were investigated. Both L. monocytogenes strains, a persistently sampled isolate (collected repeatedly along 3 years from a meat factory) and Scott A, induced shrinkage in matrix volume, both at 20°C and 4°C, in mature or old biofilms, without loss of P. fluorescens cell count per surface unit. The nearly homogeneous pattern of surface coverage shown by mono-species P. fluorescens biofilms, turned into more irregular layouts in co-culture with L. monocytogenes. The upper layer of both mono and dual-species biofilms turned to predominantly consist of matrix, with plenty of viable cells underneath, in old biofilms cultured at 20°C, but not in those grown at 4°C. Between 15 and 56% of the substratum area was covered by biofilm, the extent depending on temperature, time and L. monocytogenes strain. Real biofilms in food-related surfaces may thus be very heterogeneous regarding their superficial components, i.e., those more accessible to disinfectants. It is therefore a hygienic challenge to choose an adequate agent to disrupt them.

  9. Listeria monocytogenes impact on mature or old Pseudomonas fluorescens biofilms during growth at 4 and 20ºC

    Directory of Open Access Journals (Sweden)

    Puga eCH

    2016-02-01

    Full Text Available Changes in spatial organization, as observed by confocal laser scanning microscopy (CLSM, viable cell content, biovolume and substratum surface coverage of the biofilms formed on glass by Pseudomonas fluorescens resulting from co-culture with Listeria monocytogenes, were examined. Two strains of L. monocytogenes, two culture temperatures and two biofilm developmental stages were investigated. Both L. monocytogenes strains, a persistently sampled isolate (collected repeatedly along 3 years from a meat factory and Scott A, induced shrinkage in matrix volume, both at 20ºC and 4ºC, in mature or old biofilms, without loss of P. fluorescens cell count per surface unit. The nearly homogeneous pattern of surface coverage shown by mono-species P. fluorescens biofilms, turned into more irregular layouts in co-culture with L. monocytogenes. The upper layer of both mono and dual-species biofilms turned to predominantly consist of matrix, with plenty of viable cells underneath, in old biofilms cultured at 20ºC, but not in those grown at 4ºC. Between 15 and 56% of the substratum area was covered by biofilm, the extent depending on temperature, time and L. monocytogenes strain. Real biofilms in food-related surfaces may thus be very heterogeneous regarding their superficial components, i.e. those more accessible to disinfectants. It is therefore a hygienic challenge to choose an adequate agent to disrupt them.

  10. Three Alginate Lyases from Marine Bacterium Pseudomonas fluorescens HZJ216: Purification and Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Liyan, Li [Ocean University of China, Qingdao, PRC; Jiang, Xiaolu [Ocean University of China, Qingdao, PRC; Wang, Peng [Ocean University of China, Qingdao, PRC; Guan, Huashi [Ocean University of China, Qingdao, PRC; Guo, Hong [ORNL

    2010-01-01

    Three alginate lyases (A, B, and C) from an alginate-degrading marine bacterium strain HZJ216 isolated from brown seaweed in the Yellow Sea of China and identified preliminarily as Pseudomonas fluorescens are purified, and their biochemical properties are described. Molecular masses of the three enzymes are determined by SDS-PAGE to be 60.25, 36, and 23 kDa with isoelectric points of 4, 4.36, and 4.59, respectively. Investigations of these enzymes at different pH and temperatures show that they are most active at pH 7.0 and 35 C. Alginate lyases A and B are stable in the pH range of 5.0 9.0, while alginate lyase C is stable in the pH range of 5.0 7.0. Among the metal ions tested, additions of Na+, K+, and Mg2+ ions can enhance the enzyme activities while Fe2+, Fe3+, Ba2+, and Zn2+ ions show inhibitory effects. The substrate specificity results demonstrate that alginate lyase C has the specificity for G block while alginate lyases A and B have the activities for both M and G blocks. It is the first report about extracellular alginate lyases with high alginate-degrading activity from P. fluorescens.

  11. Purification and characterization of an exo-type β-N-acetylglucosaminidase from Pseudomonas fluorescens JK-0412.

    Science.gov (United States)

    Park, J K; Kim, W J; Park, Y I

    2011-01-01

    To purify and characterize an exo-acting chitinolytic enzyme produced from a Gram-negative bacterium Pseudomonas fluorescens JK-0412. A chitinolytic bacterial strain that showed confluent growth on a minimal medium containing powder chitin as the sole carbon source was isolated and identified based on a 16S ribosomal DNA sequence analysis and named Ps. fluorescens JK-0412. From the culture filtrates of this strain, a chito-oligosaccharides-degrading enzyme was purified to apparent homogeneity with a molecular mass of 50 kDa on SDS-PAGE gels. The kinetics, optimum pH and temperature, and substrate specificity of the purified enzyme (named as NagA) were determined. An extracellular chitinolytic enzyme was purified from the Ps. fluorescens JK-0412 and shown to be an exo-type β-N-acetylglucosaminidase yielding GlcNAc as the final product from the natural chito-oligosaccharides, (GlcNAc)(n) , n = 2-5. As NagA is secreted extracellularly in the presence of colloidal chitin, Ps. fluorescens JK-0412 can be recognized as a potent producer for industry-level and cost-effective production of chitinolytic enzyme. This enzyme appears to have potential applications as an efficient tool for the degradation of chitinous materials and industry-level production of GlcNAc. To the best of our knowledge, this is the first report on an exo-type chitinolytic enzyme of Pseudomonas species. © 2010 The Authors. Journal of Applied Microbiology © 2010 The Society for Applied Microbiology.

  12. Detection of Pseudomonas fluorescens from broth, water and ...

    African Journals Online (AJOL)

    Loop mediated isothermal amplification is rapid, highly sensitive and specifically developed method for detection of bacterial infections. AprX gene for alkaline metalloprotease of Pseudomonas fluorescens was used to design four primers and loop mediated isothermal amplification (LAMP) conditions were standardized for ...

  13. Detection of Pseudomonas fluorescens from broth, water and ...

    African Journals Online (AJOL)

    sonal

    2015-04-08

    Apr 8, 2015 ... Full Length Research Paper. Detection of Pseudomonas fluorescens from broth, water and infected tissues by loop-mediated isothermal amplification (LAMP) method. Pooja Saharan, Joginder S. Duhan and Suresh K. Gahlawat*. Department of Biotechnology, Chaudhary Devi Lal University, Sirsa-125 055, ...

  14. Adaptive synonymous mutations in an experimentally evolved Pseudomonas fluorescens population

    DEFF Research Database (Denmark)

    Bailey, Susan; Hinz, Aaron; Kassen, Rees

    2014-01-01

    in an experimentally evolved population of Pseudomonas fluorescens. We show experimentally that these mutations increase fitness by an amount comparable to non-synonymous mutations and that the fitness increases stem from increased gene expression. These results provide unequivocal evidence that synonymous mutations...

  15. Identification and characterization of the emhABC efflux system for polycyclic aromatic hydrocarbons in Pseudomonas fluorescens cLP6a.

    Science.gov (United States)

    Hearn, Elizabeth M; Dennis, Jonathan J; Gray, Murray R; Foght, Julia M

    2003-11-01

    The hydrocarbon-degrading environmental isolate Pseudomonas fluorescens LP6a possesses an active efflux mechanism for the polycyclic aromatic hydrocarbons phenanthrene, anthracene, and fluoranthene but not for naphthalene or toluene. PCR was used to detect efflux pump genes belonging to the resistance-nodulation-cell division (RND) superfamily in a plasmid-cured derivative, P. fluorescens cLP6a, which is unable to metabolize hydrocarbons. One RND pump, whose gene was identified in P. fluorescens cLP6a and was designated emhB, showed homology to the multidrug and solvent efflux pumps in Pseudomonas aeruginosa and Pseudomonas putida. The emhB gene is located in a gene cluster with the emhA and emhC genes, which encode the membrane fusion protein and outer membrane protein components of the efflux system, respectively. Disruption of emhB by insertion of an antibiotic resistance cassette demonstrated that the corresponding gene product was responsible for the efflux of polycyclic aromatic hydrocarbons. The emhB gene disruption did not affect the resistance of P. fluorescens cLP6a to tetracycline, erythromycin, trimethoprim, or streptomycin, but it did decrease resistance to chloramphenicol and nalidixic acid, indicating that the EmhABC system also functions in the efflux of these compounds and has an unusual selectivity. Phenanthrene efflux was observed in P. aeruginosa, P. putida, and Burkholderia cepacia but not in Azotobacter vinelandii. Polycyclic aromatic hydrocarbons represent a new class of nontoxic, highly hydrophobic compounds that are substrates of RND efflux systems, and the EmhABC system in P. fluorescens cLP6a has a narrow substrate range for these hydrocarbons and certain antibiotics.

  16. Binding sites of mosquitocidal toxins of Pseudomonas fluorescens and Bacillus subtilis on pupae and larvae of Culex quinquefasciatus.

    Science.gov (United States)

    Mary, K Athisaya; Paily, K P; Hoti, S L; Balaraman, K

    2015-01-01

    Two of the potential bacterial isolates, viz., Pseudomonas fluorescens (VCRC B-426) and Bacillus subtilis (VCRC B-471) whose toxins kill the mosquito pupae/larvae have been identified at our center. As the mode of action of these bacteria are not known, an attempt was made to find out the binding sites of the toxic proteins through immunological methods. Antibodies were raised in BALB/c mice and egg yolk system of chicken layers against the mosquitocidal proteins. The antibodies showed specific binding on to the cephalic and thoracic cuticle of the pupae as well as the paddles of the larvae, indicating the binding of the mosquitocidal proteins.

  17. Semi-scale production of PHAs from waste frying oil by Pseudomonas fluorescens S48

    Science.gov (United States)

    Gamal, Rawia F.; Abdelhady, Hemmat M.; Khodair, Taha A.; El-Tayeb, Tarek S.; Hassan, Enas A.; Aboutaleb, Khadiga A.

    2013-01-01

    The present study aimed at developing a strategy to improve the volumetric production of PHAs by Pseudomonas fluorescens S48 using waste frying oil (WFO) as the sole carbon source. For this purpose, several cultivations were set up to steadily improve nutrients supply to attain high cell density and high biopolymer productivity. The production of PHAs was examined in a 14 L bioreactor as one-stage batch, two-stage batch, and high-cell-density fed-batch cultures. The highest value of polymer content in one-stage bioreactor was obtained after 60 h (33.7%). Whereas, the two-stage batch culture increased the polymer content to 50.1% after 54 h. High-cell-density (0.64 g/L) at continuous feeding rate 0.55 mL/l/h of WFO recorded the highest polymer content after 54 h (55.34%). Semi-scale application (10 L working volume) increased the polymer content in one-stage batch, two-stage batch and high cell density fed-batch cultures by about 12.3%, 5.8% and 11.3%, respectively, as compared with that obtained in 2 L fermentation culture. Six different methods for biopolymer extraction were done to investigate their efficiency for optimum polymer recovery. The maximum efficiency of solvent recovery of PHA was attained by chloroform–hypochlorite dispersion extraction. Gas chromatography (GC) analysis of biopolymer produced by Pseudomonas fluorescens S48 indicated that it solely composed of 3-hydrobutyric acid (98.7%). A bioplastic film was prepared from the obtained PHB. The isolate studied shares the same identical sequence, which is nearly the complete 16S rRNA gene. The identity of this sequence to the closest pseudomonads strains is about 98–99%. It was probably closely related to support another meaningful parsiomony analysis and construction of a phylogenetic tree. The isolate is so close to Egyptian strain named EG 639838. PMID:24294253

  18. Genome Sequence of the Biocontrol Strain Pseudomonas fluorescens F113

    Science.gov (United States)

    Redondo-Nieto, Miguel; Barret, Matthieu; Morrisey, John P.; Germaine, Kieran; Martínez-Granero, Francisco; Barahona, Emma; Navazo, Ana; Sánchez-Contreras, María; Moynihan, Jennifer A.; Giddens, Stephen R.; Coppoolse, Eric R.; Muriel, Candela; Stiekema, Willem J.; Rainey, Paul B.; Dowling, David; O'Gara, Fergal; Martín, Marta

    2012-01-01

    Pseudomonas fluorescens F113 is a plant growth-promoting rhizobacterium (PGPR) that has biocontrol activity against fungal plant pathogens and is a model for rhizosphere colonization. Here, we present its complete genome sequence, which shows that besides a core genome very similar to those of other strains sequenced within this species, F113 possesses a wide array of genes encoding specialized functions for thriving in the rhizosphere and interacting with eukaryotic organisms. PMID:22328765

  19. Effect of Pseudomonas fluorescens on Buried Steel Pipeline Corrosion.

    Science.gov (United States)

    Spark, Amy J; Law, David W; Ward, Liam P; Cole, Ivan S; Best, Adam S

    2017-08-01

    Buried steel infrastructure can be a source of iron ions for bacterial species, leading to microbiologically influenced corrosion (MIC). Localized corrosion of pipelines due to MIC is one of the key failure mechanisms of buried steel pipelines. In order to better understand the mechanisms of localized corrosion in soil, semisolid agar has been developed as an analogue for soil. Here, Pseudomonas fluorescens has been introduced to the system to understand how bacteria interact with steel. Through electrochemical testing including open circuit potentials, potentiodynamic scans, anodic potential holds, and electrochemical impedance spectroscopy it has been shown that P. fluorescens increases the rate of corrosion. Time for oxide and biofilms to develop was shown to not impact on the rate of corrosion but did alter the consistency of biofilm present and the viability of P. fluorescens following electrochemical testing. The proposed mechanism for increased corrosion rates of carbon steel involves the interactions of pyoverdine with the steel, preventing the formation of a cohesive passive layer, after initial cell attachment, followed by the formation of a metal concentration gradient on the steel surface.

  20. 40 CFR 180.1200 - Pseudomonas fluorescens strain PRA-25; temporary exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Pseudomonas fluorescens strain PRA-25... RESIDUES IN FOOD Exemptions From Tolerances § 180.1200 Pseudomonas fluorescens strain PRA-25; temporary... established for residues of the microbial pesticide, pseudomonas fluorescens strain PRA-25 when used on peas...

  1. Effects of cysteine on growth, protease production, and catalase activity of Pseudomonas fluorescens.

    OpenAIRE

    Himelbloom, B H; Hassan, H M

    1986-01-01

    Cysteine inhibits growth of and protease production by Pseudomonas fluorescens NC3. Catalase activity in P. fluorescens NC3 was increased by cysteine. The addition of exogenous hydrogen peroxide did not increase catalase activity, thus suggesting a role for the endogenous generation of hydrogen peroxide via the autoxidation of cysteine.

  2. Three Strains of Pseudomonas fluorescens Exhibit Differential Toxicity Against Drosophila melanogaster

    Science.gov (United States)

    Three strains of Pseudomonas fluorescens were tested for toxicity to Drosophila melanogaster in an insect feeding assay. Insect eggs were placed on the surface of a non-nutritive agar plate supplemented with a food source that was non-inoculated or inoculated with P. fluorescens Pf0-1, SBW25, or Pf-...

  3. Nitrilase from Pseudomonas fluorescens EBC191: cloning and heterologous expression of the gene and biochemical characterization of the recombinant enzyme.

    Science.gov (United States)

    Kiziak, Christoph; Conradt, Doris; Stolz, Andreas; Mattes, Ralf; Klein, Joachim

    2005-11-01

    The gene encoding an enantioselective arylacetonitrilase was identified on a 3.8 kb DNA fragment from the genomic DNA of Pseudomonas fluorescens EBC191. The gene was isolated, sequenced and cloned into the L-rhamnose-inducible expression vector pJOE2775. The nitrilase was produced in large quantities and purified as a histidine-tagged enzyme from crude extracts of L-rhamnose-induced cells of Escherichia coli JM109. The purified nitrilase was significantly stabilized during storage by the addition of 1 M ammonium sulfate. The temperature optimum (50 degrees C), pH optimum (pH 6.5), and specific activity of the recombinant nitrilase were similar to those of the native enzyme from P. fluorescens EBC191. The enzyme hydrolysed various phenylacetonitriles with different substituents in the 2-position and also heterocyclic and bicyclic arylacetonitriles to the corresponding carboxylic acids. The conversion of most arylacetonitriles was accompanied by the formation of different amounts of amides as by-products. The relative amounts of amides formed from different nitriles increased with an increasing negative inductive effect of the substituent in the 2-position. The acids and amides that were formed from chiral nitriles demonstrated in most cases opposite enantiomeric excesses. Thus mandelonitrile was converted by the nitrilase preferentially to R-mandelic acid and S-mandelic acid amide. The nitrilase gene is physically linked in the genome of P. fluorescens with genes encoding the degradative pathway for mandelic acid. This might suggest a natural function of the nitrilase in the degradation of mandelonitrile or similar naturally occurring hydroxynitriles.

  4. Binding of Pu(IV) to galacturonic acid and extracellular polymeric substances (EPS) from Shewanella putrefaciens, Clostridium sp. and Pseudomonas fluorescens

    International Nuclear Information System (INIS)

    Harper, R.M.; Kantar, C.; Honeyman, B.D.

    2008-01-01

    The conditional stability constants for trace-level concentrations of Pu(IV) complexing with galacturonic acid and EPS, isolated from axenic Clostridium sp., P. fluorescens and Shewanella putrefaciens CN32 cultures, were determined at pH 4 and an ionic strength of 0.1 M NaCl using an ion-exchange technique. The analysis of ion-exchange data with Schubert's technique indicates that the Pu binding by galacturonic acid and EPS from Clostridium sp. and S. putrefaciens can be described based on the formation of 1: 1 Pu(IV)-ligand complexes. However, the accurate description of Pu binding by EPS from P. fluorescens requires postulation of a mixture of 1: 1/1: 2 complexes between Pu(IV) and ligands under the experimental conditions studied. The results from the ion-exchange experiments were also modeled based on a non-electrostatic, discrete ligand approach in which bacterial EPS is conceptualized as being composed of a suite of monoprotic acids, HL 1 , of arbitrarily-assigned pK a (i) values (e.g., 4, 6 and 8). The examination of ion-exchange data in a chemical model suggested that only the pK a 4 (L 1 ) and 6 (L 2 ) ligands are sufficient to accurately simulate the Pu(IV)/EPS binding, implying that carboxylic groups in EPS are the primary binding sites for complexing with Pu(IV) under the experimental conditions examined. The affinity of EPS for complexing Pu(IV) decreases in the order of Clostridium sp. > S. putrefaciens > P. fluorescens although the concentrations of carboxylic groups in EPS decrease in the order of P. fluorescens > S. putrefaciens > Clostridium sp. This discrepancy may be due to differences in binding affinities between Na + ion in solution and EPS ligands. At I = 0.1 M, models demonstrated that the EPS from P. fluorescens exhibits a much stronger affinity for the Na + ion compared to ligands from other EPS; therefore, the deprotonated carboxylic sites of EPS from P. fluorescens are hypothesized to be mostly bound by Na + in solution. (orig.)

  5. Genomic and Genetic Diversity within the Pseudomonas fluorescens Complex.

    Directory of Open Access Journals (Sweden)

    Daniel Garrido-Sanz

    Full Text Available The Pseudomonas fluorescens complex includes Pseudomonas strains that have been taxonomically assigned to more than fifty different species, many of which have been described as plant growth-promoting rhizobacteria (PGPR with potential applications in biocontrol and biofertilization. So far the phylogeny of this complex has been analyzed according to phenotypic traits, 16S rDNA, MLSA and inferred by whole-genome analysis. However, since most of the type strains have not been fully sequenced and new species are frequently described, correlation between taxonomy and phylogenomic analysis is missing. In recent years, the genomes of a large number of strains have been sequenced, showing important genomic heterogeneity and providing information suitable for genomic studies that are important to understand the genomic and genetic diversity shown by strains of this complex. Based on MLSA and several whole-genome sequence-based analyses of 93 sequenced strains, we have divided the P. fluorescens complex into eight phylogenomic groups that agree with previous works based on type strains. Digital DDH (dDDH identified 69 species and 75 subspecies within the 93 genomes. The eight groups corresponded to clustering with a threshold of 31.8% dDDH, in full agreement with our MLSA. The Average Nucleotide Identity (ANI approach showed inconsistencies regarding the assignment to species and to the eight groups. The small core genome of 1,334 CDSs and the large pan-genome of 30,848 CDSs, show the large diversity and genetic heterogeneity of the P. fluorescens complex. However, a low number of strains were enough to explain most of the CDSs diversity at core and strain-specific genomic fractions. Finally, the identification and analysis of group-specific genome and the screening for distinctive characters revealed a phylogenomic distribution of traits among the groups that provided insights into biocontrol and bioremediation applications as well as their role as

  6. Structure Revision of N-Mercapto-4-formylcarbostyril Produced by Pseudomonas fluorescens G308 to 2-(2-Hydroxyphenyl)thiazole-4-carbaldehyde [aeruginaldehyde

    DEFF Research Database (Denmark)

    Guillemyn, Karel; Ballet, Steven; Ye, Lumeng

    2014-01-01

    An antibiotic substance isolated from Pseudomonas fluorescens strain G308 was earlier assigned the structure of N-mercapto-4-formylcarbostyril, but computational predictions of the H-1 and C-13 NMR magnetic shielding tensors show this structure to be incompatible with the published spectroscopic...... data. The same is true for six quinoline derivatives related to N-mercapto-4-formylcarbostyril by permutation of the O and S atoms. In contrast, 2-(2-hydroxyphenyl)thiazole-4-carbaldehyde [aeruginaldehyde], isolated from Pseudomonas protegens Pf-5, together with the reduced derivative aeruginol...

  7. Factors Affecting Zebra Mussel Kill by the Bacterium Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2004-02-24

    The specific purpose of this research project was to identify factors that affect zebra mussel kill by the bacterium Pseudomonas fluorescens. Test results obtained during this three-year project identified the following key variables as affecting mussel kill: treatment concentration, treatment duration, mussel siphoning activity, dissolved oxygen concentration, water temperature, and naturally suspended particle load. Using this latter information, the project culminated in a series of pipe tests which achieved high mussel kill inside power plants under once-through conditions using service water in artificial pipes.

  8. Mutation rate, spectrum, topology, and context-dependency in the DNA mismatch repair-deficient Pseudomonas fluorescens ATCC948.

    Science.gov (United States)

    Long, Hongan; Sung, Way; Miller, Samuel F; Ackerman, Matthew S; Doak, Thomas G; Lynch, Michael

    2014-12-23

    High levels of genetic diversity exist among natural isolates of the bacterium Pseudomonas fluorescens, and are especially elevated around the replication terminus of the genome, where strain-specific genes are found. In an effort to understand the role of genetic variation in the evolution of Pseudomonas, we analyzed 31,106 base substitutions from 45 mutation accumulation lines of P. fluorescens ATCC948, naturally deficient for mismatch repair, yielding a base-substitution mutation rate of 2.34 × 10(-8) per site per generation (SE: 0.01 × 10(-8)) and a small-insertion-deletion mutation rate of 1.65 × 10(-9) per site per generation (SE: 0.03 × 10(-9)). We find that the spectrum of mutations in prophage regions, which often contain virulence factors and antibiotic resistance, is highly similar to that in the intergenic regions of the host genome. Our results show that the mutation rate varies around the chromosome, with the lowest mutation rate found near the origin of replication. Consistent with observations from other studies, we find that site-specific mutation rates are heavily influenced by the immediately flanking nucleotides, indicating that mutations are context dependent. © The Author(s) 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  9. Biocontrol of avocado dematophora root rot by antagonistic Pseudomonas fluorescens PCL1606 correlates with the production of 2-hexyl 5-propyl resorcinol.

    Science.gov (United States)

    Cazorla, Francisco M; Duckett, Simon B; Bergström, Ed T; Noreen, Sadaf; Odijk, Roeland; Lugtenberg, Ben J J; Thomas-Oates, Jane E; Bloemberg, Guido V

    2006-04-01

    A collection of 905 bacterial isolates from the rhizospheres of healthy avocado trees was obtained and screened for antagonistic activity against Dematophora necatrix, the cause of avocado Dematophora root rot (also called white root rot). A set of eight strains was selected on the basis of growth inhibitory activity against D. necatrix and several other important soilborne phytopathogenic fungi. After typing of these strains, they were classified as belonging to Pseudomonas chlororaphis, Pseudomonas fluorescens, and Pseudomonas putida. The eight antagonistic Pseudomonas spp. were analyzed for their secretion of hydrogen cyanide, hydrolytic enzymes, and antifungal metabolites. P. chlororaphis strains produced the antibiotic phenazine-1-carboxylic acid and phenazine-1-carboxamide. Upon testing the biocontrol ability of these strains in a newly developed avocado-D. necatrix test system and in a tomato-F oxysporum test system, it became apparent that P. fluorescens PCL1606 exhibited the highest biocontrol ability. The major antifungal activity produced by strain P. fluorescens PCL1606 did not correspond to any of the major classes of antifungal antibiotics produced by Pseudomonas biocontrol strains. This compound was purified and subsequently identified as 2-hexyl 5-propyl resorcinol (HPR). To study the role of HPR in biocontrol activity, two Tn5 mutants of P. fluorescens PCL1606 impaired in antagonistic activity were selected. These mutants were shown to impair HRP production and showed a decrease in biocontrol activity. As far as we know, this is the first report of a Pseudomonas biocontrol strain that produces HPR in which the production of this compound correlates with its biocontrol activity.

  10. Boolean models of biosurfactants production in Pseudomonas fluorescens.

    Directory of Open Access Journals (Sweden)

    Adrien Richard

    Full Text Available Cyclolipopeptides (CLPs are biosurfactants produced by numerous Pseudomonas fluorescens strains. CLP production is known to be regulated at least by the GacA/GacS two-component pathway, but the full regulatory network is yet largely unknown. In the clinical strain MFN1032, CLP production is abolished by a mutation in the phospholipase C gene (plcC and not restored by plcC complementation. Their production is also subject to phenotypic variation. We used a modelling approach with Boolean networks, which takes into account all these observations concerning CLP production without any assumption on the topology of the considered network. Intensive computation yielded numerous models that satisfy these properties. All models minimizing the number of components point to a bistability in CLP production, which requires the presence of a yet unknown key self-inducible regulator. Furthermore, all suggest that a set of yet unexplained phenotypic variants might also be due to this epigenetic switch. The simplest of these Boolean networks was used to propose a biological regulatory network for CLP production. This modelling approach has allowed a possible regulation to be unravelled and an unusual behaviour of CLP production in P. fluorescens to be explained.

  11. Combined inoculation of Pseudomonas fluorescens and Trichoderma harzianum for enhancing plant growth of vanilla (Vanilla planifolia).

    Science.gov (United States)

    Sandheep, A R; Asok, A K; Jisha, M S

    2013-06-15

    This study was conducted to evaluate the plant growth promoting efficiency of combined inoculation of rhizobacteria on Vanilla plants. Based on the in vitro performance of indigenous Trichoderma spp. and Pseudomonas spp., four effective antagonists were selected and screened under greenhouse experiment for their growth enhancement potential. The maximum percentage of growth enhancement were observed in the combination of Trichoderma harzianum with Pseudomonas fluorescens treatment followed by Pseudomonas fluorescens, Trichoderma harzianum, Pseudomonas putida and Trichoderma virens, respectively in decreasing order. Combined inoculation of Trichoderma harzianum and Pseudomonas fluorescens registered the maximum length of vine (82.88 cm), highest number of leaves (26.67/plant), recorded the highest fresh weight of shoots (61.54 g plant(-1)), fresh weight of roots (4.46 g plant(-1)) and dry weight of shoot (4.56 g plant(-1)) where as the highest dry weight of roots (2.0806 g plant(-1)) were achieved with treatments of Pseudomonas fluorescens. Among the inoculated strains, combined inoculation of Trichoderma harzianum and Pseudomonas fluorescens recorded the maximum nitrogen uptake (61.28 mg plant(-1)) followed by the combined inoculation of Trichoderma harzianum (std) and Pseudomonas fluorescens (std) (55.03 mg plant(-1)) and the highest phosphorus uptake (38.80 mg plant(-1)) was recorded in dual inoculation of Trichoderma harzianum and Pseudomonas fluorescens.

  12. Semi-scale production of PHAs from waste frying oil by Pseudomonas fluorescens S48

    Directory of Open Access Journals (Sweden)

    Rawia F. Gamal

    2013-01-01

    Full Text Available The present study aimed at developing a strategy to improve the volumetric production of PHAs by Pseudomonas fluorescens S48 using waste frying oil (WFO as the sole carbon source. For this purpose, several cultivations were set up to steadily improve nutrients supply to attain high cell density and high biopolymer productivity. The production of PHAs was examined in a 14 L bioreactor as one-stage batch, two-stage batch, and high-cell-density fed-batch cultures. The highest value of polymer content in one-stage bioreactor was obtained after 60 h (33.7%. Whereas, the two-stage batch culture increased the polymer content to 50.1% after 54 h. High-cell-density (0.64 g/L at continuous feeding rate 0.55 mL/l/h of WFO recorded the highest polymer content after 54 h (55.34%. Semi-scale application (10 L working volume increased the polymer content in one-stage batch, two-stage batch and high cell density fed-batch cultures by about 12.3%, 5.8% and 11.3%, respectively, as compared with that obtained in 2 L fermentation culture. Six different methods for biopolymer extraction were done to investigate their efficiency for optimum polymer recovery. The maximum efficiency of solvent recovery of PHA was attained by chloroform-hypochlorite dispersion extraction. Gas chromatography (GC analysis of biopolymer produced by Pseudomonas fluorescens S48 indicated that it solely composed of 3-hydrobutyric acid (98.7%. A bioplastic film was prepared from the obtained PHB. The isolate studied shares the same identical sequence, which is nearly the complete 16S rRNA gene. The identity of this sequence to the closest pseudomonads strains is about 98-99%. It was probably closely related to support another meaningful parsiomony analysis and construction of a phylogenetic tree. The isolate is so close to Egyptian strain named EG 639838.

  13. Isolation, molecular and biochemical characterization of oil ...

    African Journals Online (AJOL)

    Biochemical and physiological characterization performed on the 34 bacterial isolates, revealed the presence of oil biodegrading bacterial genera and species of Pseudomonas Acidovorans, P. aerugi-nosa, P. alcaligenes, P. fluorescens, P. cepacia, P. mallei, P. maltophilia, P. oleovorans, P. putida, P. stutzeri P. vesicularis, ...

  14. Promotion of plant growth by Pseudomonas fluorescens strain SS101 via novel volatile organic compounds

    NARCIS (Netherlands)

    Park, Yong-Soon; Dutta, Swarnalee; Ann, Mina; Raaijmakers, Jos M.; Park, Kyungseok

    2015-01-01

    Abstract Volatile organic compounds (VOCs) from plant growth-promoting rhizobacteria (PGPR) play key roles in modulating plant growth and induced systemic resistance (ISR) to pathogens. Despite their significance, the physiological functions of the specific VOCs produced by Pseudomonas fluorescens

  15. Metabolic and transcriptomic changes induced in Arabidopsis by the rhizobacterium Pseudomonas fluorescens SS101

    NARCIS (Netherlands)

    Mortel, van de J.E.; Vos, de R.C.H.; Dekkers, E.; Pineda, A.; Guillod, L.; Bouwmeester, K.; Loon, van J.J.A.; Dicke, M.; Raaijmakers, J.M.

    2012-01-01

    Systemic resistance induced in plants by nonpathogenic rhizobacteria is typically effective against multiple pathogens. Here, we show that root-colonizing Pseudomonas fluorescens strain SS101 (Pf.SS101) enhanced resistance in Arabidopsis (Arabidopsis thaliana) against several bacterial pathogens,

  16. Discovery of new regulatory genes of lipopeptide biosynthesis in Pseudomonas fluorescens

    NARCIS (Netherlands)

    Song, C.; Aundy, K.; Mortel, van de J.E.; Raaijmakers, J.M.

    2014-01-01

    Pseudomonas fluorescens SS101 produces the cyclic lipopeptide massetolide with diverse functions in antimicrobial activity, motility, and biofilm formation. To understand how massetolide biosynthesis is genetically regulated in SS101, c. 8000 random plasposon mutants were screened for reduced or

  17. Bioreporter pseudomonas fluorescens HK44 immobilized in a silica matrix

    Directory of Open Access Journals (Sweden)

    Trogl J.

    2003-01-01

    Full Text Available The bioluminescent bioreporter Pseudomonas fluorescens HK44, the whole cell bacterial biosensor that responds to naphthalene and its metabolites via the production of visible light, was immobilized into a silica matrix by the sol-gel technique. The bioluminescence intensities were measured in the maximum of the bioluminescence band at X = 500 nm. The immobilized cells (>105 cells per g silica matrix produced light after induction by salicylate (cone. > 10 g/l, naphthalene and aminobenzoic acid. The bioluminescence intensities induced by 2,3-dihydroxynaphthalene 3-hydroxybenzoic acid and 4-hydroxybenzoic acid were comparable to a negative control. The cells in the silica layers on glass slides produced light in response to the presence of an inductor at least 8 months after immobilization, and >50 induction cycles. The results showed that these test slides could be used as assays for the multiple determination of water pollution.

  18. Pseudomonas fluorescens alters epithelial permeability and translocates across Caco-2/TC7 intestinal cells

    Directory of Open Access Journals (Sweden)

    Madi Amar

    2010-11-01

    Full Text Available Abstract Background Pseudomonas fluorescens has long been considered as a psychrotrophic microorganism. Recently, we have shown that clinical strains of P. fluorescens (biovar 1 are able to adapt at a growth temperature of 37°C or above and induce a specific inflammatory response. Interestingly, a highly specific antigen of P. fluorescens, I2, is detected in the serum of patients with Crohn's disease but the possible role of this bacterium in the disease has not yet been explored. In the present study, we examined the ability of a psychrotrophic and a clinical strain of P. fluorescens to modulate the permeability of a Caco-2/TC7 intestinal epithelial model, reorganize the actin cytoskeleton, invade the target cells and translocate across the epithelium. The behaviour of these two strains was compared to that of the well known opportunistic pathogen P. aeruginosa PAO1. Results Both strains of P. fluorescens were found to decrease the transepithelial resistance (TER of Caco-2/TC7 differentiated monolayers. This was associated with an increase in paracellular permeability and F-actin microfilaments rearrangements. Moreover, the invasion and translocation tests demonstrated that the two strains used in this study can invade and translocate across the differentiated Caco-2/TC7 cell monolayers. Conclusions The present work shows for the first time, that P. fluorescens is able to alter the intestinal epithelial barrier function by disorganizing the F-actin microfilament network. Moreover, we reveal that independently of their origins, the two P. fluorescens strains can translocate across differentiated Caco-2/TC7 cell monolayers by using the transcellular pathway. These findings could, at least in part, explain the presence of the P. fluorescens specific I2 antigen in the serum of patients with Crohn's disease.

  19. Transcriptomic profiling of microbe-microbe interactions reveals the specific response of the biocontrol strain P. fluorescens In5 to the phytopathogen Rhizoctonia solani.

    Science.gov (United States)

    Hennessy, Rosanna C; Glaring, Mikkel A; Olsson, Stefan; Stougaard, Peter

    2017-08-10

    Few studies to date report the transcriptional response of biocontrol bacteria toward phytopathogens. In order to gain insights into the potential mechanism underlying the antagonism of the antimicrobial producing strain P. fluorescens In5 against the phytopathogens Rhizoctonia solani and Pythium aphanidermatum, global RNA sequencing was performed. Differential gene expression profiling of P. fluorescens In5 in response to either R. solani or P. aphanidermatum was investigated using transcriptome sequencing (RNA-seq). Total RNA was isolated from single bacterial cultures of P. fluorescens In5 or bacterial cultures in dual-culture for 48 h with each pathogen in biological triplicates. RNA-seq libraries were constructed following a default Illumina stranded RNA protocol including rRNA depletion and were sequenced 2 × 100 bases on Illumina HiSeq generating approximately 10 million reads per sample. No significant changes in global gene expression were recorded during dual-culture of P. fluorescens In5 with any of the two pathogens but rather each pathogen appeared to induce expression of a specific set of genes. A particularly strong transcriptional response to R. solani was observed and notably several genes possibly associated with secondary metabolite detoxification and metabolism were highly upregulated in response to the fungus. A total of 23 genes were significantly upregulated and seven genes were significantly downregulated with at least respectively a threefold change in expression level in response to R. solani compared to the no fungus control. In contrast, only one gene was significantly upregulated over threefold and three transcripts were significantly downregulated over threefold in response to P. aphanidermatum. Genes known to be involved in synthesis of secondary metabolites, e.g. non-ribosomal synthetases and hydrogen cyanide were not differentially expressed at the time points studied. This study demonstrates that genes possibly involved in

  20. Pseudomonas fluorescens R68 assisted enhancement in growth and fertilizer utilization of Amaranthus tricolor (L.).

    Science.gov (United States)

    Jimtha John, C; Jishma, P; Karthika, N R; Nidheesh, K S; Ray, J G; Mathew, Jyothis; Radhakrishnan, E K

    2017-08-01

    Plant probiotic potential of rhizosphere microbiome and its role in phytofertilizer mobilization are largely unexplored. In the current study, the rhizobacterium Pseudomonas fluorescens R68 (PFR68) isolated from Western Ghat was analyzed for its growth enhancement effect on the leafy vegetable Amaranthus tricolor (L.). One month of field growth of PFR68 inoculated A. tricolor has found to have enhanced growth parameters such as leaf number (1.57 fold), root number (1.76 fold), shoot length (1.28 fold) and fresh weight (2.31 fold). The treatment also improved soil fertility in terms of Nitrogen, Phosphorus and Potassium content. Most remarkably, application of PFR68 alone and 50% of recommended NPK dose along with PFR68 has resulted in enhanced growth of A. tricolor comparable to plants treated with full dose of NPK. In addition to this, application of PFR68 along with 50% NPK augmented the available Nitrogen and Phosphorus content in soil. This indicates the potential of selected organism in enrichment of soil health and enhancement of crop productivity. In conclusion, field performance of PFR68 on growth of A. tricolor confirms its promises to develop into plant probiotic formulation.

  1. Getting the ecology into interactions between plants and the plant growth-promoting bacterium Pseudomonas fluorescens.

    Science.gov (United States)

    Hol, W H Gera; Bezemer, T Martijn; Biere, Arjen

    2013-01-01

    Plant growth-promoting rhizobacteria (PGPR) are increasingly appreciated for their contributions to primary productivity through promotion of growth and triggering of induced systemic resistance in plants. Here we focus on the beneficial effects of one particular species of PGPR (Pseudomonas fluorescens) on plants through induced plant defense. This model organism has provided much understanding of the underlying molecular mechanisms of PGPR-induced plant defense. However, this knowledge can only be appreciated at full value once we know to what extent these mechanisms also occur under more realistic, species-diverse conditions as are occurring in the plant rhizosphere. To provide the necessary ecological context, we review the literature to compare the effect of P. fluorescens on induced plant defense when it is present as a single species or in combination with other soil dwelling species. Specifically, we discuss combinations with other plant mutualists (bacterial or fungal), plant pathogens (bacterial or fungal), bacterivores (nematode or protozoa), and decomposers. Synergistic interactions between P. fluorescens and other plant mutualists are much more commonly reported than antagonistic interactions. Recent developments have enabled screenings of P. fluorescens genomes for defense traits and this could help with selection of strains with likely positive interactions on biocontrol. However, studies that examine the effects of multiple herbivores, pathogens, or herbivores and pathogens together on the effectiveness of PGPR to induce plant defenses are underrepresented and we are not aware of any study that has examined interactions between P. fluorescens and bacterivores or decomposers. As co-occurring soil organisms can enhance but also reduce the effectiveness of PGPR, a better understanding of the biotic factors modulating P. fluorescens-plant interactions will improve the effectiveness of introducing P. fluorescens to enhance plant production and defense.

  2. Biological control of wheat root diseases by the CLP-producing strain Pseudomonas fluorescens HC1-07.

    Science.gov (United States)

    Yang, Ming-Ming; Wen, Shan-Shan; Mavrodi, Dmitri V; Mavrodi, Olga V; von Wettstein, Diter; Thomashow, Linda S; Guo, Jian-Hua; Weller, David M

    2014-03-01

    Pseudomonas fluorescens HC1-07, previously isolated from the phyllosphere of wheat grown in Hebei province, China, suppresses the soilborne disease of wheat take-all, caused by Gaeumannomyces graminis var. tritici. We report here that strain HC1-07 also suppresses Rhizoctonia root rot of wheat caused by Rhizoctonia solani AG-8. Strain HC1-07 produced a cyclic lipopeptide (CLP) with a molecular weight of 1,126.42 based on analysis by electrospray ionization mass spectrometry. Extracted CLP inhibited the growth of G. graminis var. tritici and R. solani in vitro. To determine the role of this CLP in biological control, plasposon mutagenesis was used to generate two nonproducing mutants, HC1-07viscB and HC1-07prtR2. Analysis of regions flanking plasposon insertions in HC1-07prtR2 and HC1-07viscB revealed that the inactivated genes were similar to prtR and viscB, respectively, of the well-described biocontrol strain P. fluorescens SBW25 that produces the CLP viscosin. Both genes in HC1-07 were required for the production of the viscosin-like CLP. The two mutants were less inhibitory to G. graminis var. tritici and R. solani in vitro and reduced in ability to suppress take-all. HC1-07viscB but not HC-07prtR2 was reduced in ability to suppress Rhizoctonia root rot. In addition to CLP production, prtR also played a role in protease production.

  3. Inhibition of quorum sensing-controlled virulence factors and biofilm formation in Pseudomonas fluorescens by cinnamaldehyde.

    Science.gov (United States)

    Li, Tingting; Wang, Dangfeng; Liu, Nan; Ma, Yan; Ding, Ting; Mei, Yongchao; Li, Jianrong

    2018-03-23

    Pseudomonas fluorescens, an important food spoiling bacteria, uses quorum sensing to control biofilm formation and motility. To date, only a few compounds targeting the LuxR-based quorum sensing system of P. fluorescens have been identified. In the present study, the quorum sensing inhibitory effect of cinnamaldehyde at sublethal concentrations was investigated in terms of inhibition of the extracellular protease, biofilm formation, and swimming and swarming motility. The total volatile basic nitrogen value was also measured to evaluate the effect of cinnamaldehyde on quality preservation of turbot fillets stored at 4 ± 1 °C for 15 days. The results showed that cinnamaldehyde significantly inhibited quorum sensing-dependent factors in P. fluorescens and extended the storage life of turbot. Unexpectedly, cinnamaldehyde did not interfere with production of AHLs (N-acylhomoserine lactones) by P. fluorescens, as shown by measurement of AHL production using GC-MS. Molecular docking analysis revealed that cinnamaldehyde can interact with the LuxR-type protein of P. fluorescens, which could constitute the molecular basis of the quorum sensing inhibition observed. These findings strongly suggest that cinnamaldehyde is a quorum sensing inhibitor with great potential for the preservation of aquatic products to guarantee food safety. Copyright © 2018 Elsevier B.V. All rights reserved.

  4. Iron-regulated metabolites of plant growth-promoting Pseudomonas fluorescens WCS374 : Their role in induced systemic resistance

    NARCIS (Netherlands)

    Djavaheri, M.

    2007-01-01

    The plant growth-promoting rhizobacterium Pseudomonas fluorescens WCS374r effectively suppresses fusarium wilt in radish by induced systemic resistance (ISR). In radish, WCS374r-mediated ISR depends partly on iron-regulated metabolites. Under iron-limiting conditions, P. fluorescens WCS374r produces

  5. The resistance-nodulation-division efflux pump EmhABC influences the production of 2,4-diacetylphloroglucinol in Pseudomonas fluorescens 2P24.

    Science.gov (United States)

    Tian, Tao; Wu, Xiao-Gang; Duan, Hui-Mei; Zhang, Li-Qun

    2010-01-01

    The polyketide metabolite 2,4-diacetylphloroglucinol (2,4-DAPG) plays a major role in the biological control of soil-borne plant diseases by Pseudomonas fluorescens 2P24. Two mutants (PM810 and PM820) with increased extracellular accumulation of 2,4-DAPG were isolated using transposon mutagenesis. The disrupted genes in these two mutants shared >80 % identity with the genes of the EmhR-EmhABC resistance-nodulation-division (RND) efflux system of P. fluorescens cLP6a. The deletion of emhA (PM802), emhB (PM803) or emhC (PM804) genes in strain 2P24 increased the extracellular accumulation of 2,4-DAPG, whereas the deletion of the emhR (PM801) gene decreased the biosynthesis of 2,4-DAPG. The promoter assay confirmed the elevated transcription of emhABC in the EmhR disrupted strain (PM801) and an indirect negative regulation of 2,4-DAPG biosynthetic locus transcription by the EmhABC efflux pump. Induction by exogenous 2,4-DAPG led to remarkable differences in transcription of chromosome-borne phlA : : lacZ fusion in PM901 and PM811 (emhA(-)) strains. Additionally, the EmhABC system in strain 2P24 was involved in the resistance to a group of toxic compounds, including ampicillin, chloramphenicol, tetracycline, ethidium bromide and crystal violet. In conclusion, our results suggest that the EmhABC system is an important element that influences the production of antibiotic 2,4-DAPG and enhances resistance to toxic compounds in P. fluorescens 2P24.

  6. HETEROLOGOUS EXPRESSION OF A CHITINASE GENE FROM AEROMONAS CAVIAEIN PSEUDOMONAS FLUORESCENS

    Directory of Open Access Journals (Sweden)

    ANTONIUS SUWANTO

    2003-01-01

    Full Text Available A transcriptional fusion for an Aeromonas caviae chitinase gene was constructed under the control of a constitutive promoter of the kanaraycin resistance gene (PKmR. The construct was inserted into a medium copy number broad host range plasmid vector to yield recombinant plasmid pAM340, which harbored transcriptional fusion PKmR- chi. Another transcriptional fusion, Ptac-chi, in a recombinant plasmid pAM630, was conducted as comparison. Triparental mating of E. coli carrying the recombinant plasmids with Pseudomotws fluorescens 5100, a phyllosphere bacterium, was performed. Pseudomonas fluorescens 5100 exconjugants were examined for constitutive expression of chitinase employing a spectrophotometric assay; they showed stronger chitin degradation activity than Escherichia coli transformants. Using a fungal antagonism plate assay, this chitinolytic P. fluorescens, however, could not inhibit selected phytopathogenic fungi.

  7. D-glucose-6-phosphate dehydrogenase (Entner-Doudoroff enzyme) from Pseudomonas fluorescens

    International Nuclear Information System (INIS)

    Lessmann, D.; Schimz, K.L.; Kurz, G.

    1975-01-01

    The existence of two different D-glucose-6-phosphate dehydrogenases in Pseudomonas fluorescens has been demonstrated. Based on their different specificity and their different metabolic regulation one enzyme is appointed to the Entner-Doudoroff pathway and the other to the hexose monophosphate pathway. A procedure is described for the isolation of that D-glucose-6-phosphate dehydrogenase which forms part of the Entner-Doudoroff pathway (Entner-Doudoroff enzyme). A 950-fold purification was achieved with an overall yield of 44%. The final preparation, having a specific activity of about 300μmol NADH formed per min per mg protein, was shown to be homogeneous. The molecular weight of the Entner-Doudoroff enzyme has been determined to be 220,000 by gel permeation chromatography, and that of the other enzyme (Zwischenferment) has been shown to be 265,000. The pI of the Entner-Doudoroff enzyme has been shown to be 5.24 and that of the Zwischenferment 4.27. The Entner-Doudoroff enzyme is stable in the range of pH 6 to 10.5 and shows its maximal acivity at pH 8.9. The Entner-Doudoroff enzyme showed specificity for NAD + as well as for NADP + and exhibited homotropic effects for D-glucose 6-phosphate. It is inhibited by ATP which acts as a negative allosteric effector. Other nucleoside triphosphates as well as ADP are also inhibitory. The enzyme catalyzes the transfer of the axial hydrogen at carbon-1 of β-D-glucopyranose 6-phosphate to the si face of carbon-4 of the nicotinamide ring and must be classified as B-side stereospecific dehydrogenase. (orig.) [de

  8. The effect of phylogenetically different bacteria on the fitness of Pseudomonas fluorescens in sand microcosms.

    Directory of Open Access Journals (Sweden)

    Olaf Tyc

    Full Text Available In most environments many microorganisms live in close vicinity and can interact in various ways. Recent studies suggest that bacteria are able to sense and respond to the presence of neighbouring bacteria in the environment and alter their response accordingly. This ability might be an important strategy in complex habitats such as soils, with great implications for shaping the microbial community structure. Here, we used a sand microcosm approach to investigate how Pseudomonas fluorescens Pf0-1 responds to the presence of monocultures or mixtures of two phylogenetically different bacteria, a Gram-negative (Pedobacter sp. V48 and a Gram-positive (Bacillus sp. V102 under two nutrient conditions. Results revealed that under both nutrient poor and nutrient rich conditions confrontation with the Gram-positive Bacillus sp. V102 strain led to significant lower cell numbers of Pseudomonas fluorescens Pf0-1, whereas confrontation with the Gram-negative Pedobacter sp. V48 strain did not affect the growth of Pseudomonas fluorescens Pf0-1. However, when Pseudomonas fluorescens Pf0-1 was confronted with the mixture of both strains, no significant effect on the growth of Pseudomonas fluorescens Pf0-1 was observed. Quantitative real-time PCR data showed up-regulation of genes involved in the production of a broad-spectrum antibiotic in Pseudomonas fluorescens Pf0-1 when confronted with Pedobacter sp. V48, but not in the presence of Bacillus sp. V102. The results provide evidence that the performance of bacteria in soil depends strongly on the identity of neighbouring bacteria and that inter-specific interactions are an important factor in determining microbial community structure.

  9. Genomic and genetic analyses of diversity and plant interactions of Pseudomonas fluorescens.

    Science.gov (United States)

    Silby, Mark W; Cerdeño-Tárraga, Ana M; Vernikos, Georgios S; Giddens, Stephen R; Jackson, Robert W; Preston, Gail M; Zhang, Xue-Xian; Moon, Christina D; Gehrig, Stefanie M; Godfrey, Scott A C; Knight, Christopher G; Malone, Jacob G; Robinson, Zena; Spiers, Andrew J; Harris, Simon; Challis, Gregory L; Yaxley, Alice M; Harris, David; Seeger, Kathy; Murphy, Lee; Rutter, Simon; Squares, Rob; Quail, Michael A; Saunders, Elizabeth; Mavromatis, Konstantinos; Brettin, Thomas S; Bentley, Stephen D; Hothersall, Joanne; Stephens, Elton; Thomas, Christopher M; Parkhill, Julian; Levy, Stuart B; Rainey, Paul B; Thomson, Nicholas R

    2009-01-01

    Pseudomonas fluorescens are common soil bacteria that can improve plant health through nutrient cycling, pathogen antagonism and induction of plant defenses. The genome sequences of strains SBW25 and Pf0-1 were determined and compared to each other and with P. fluorescens Pf-5. A functional genomic in vivo expression technology (IVET) screen provided insight into genes used by P. fluorescens in its natural environment and an improved understanding of the ecological significance of diversity within this species. Comparisons of three P. fluorescens genomes (SBW25, Pf0-1, Pf-5) revealed considerable divergence: 61% of genes are shared, the majority located near the replication origin. Phylogenetic and average amino acid identity analyses showed a low overall relationship. A functional screen of SBW25 defined 125 plant-induced genes including a range of functions specific to the plant environment. Orthologues of 83 of these exist in Pf0-1 and Pf-5, with 73 shared by both strains. The P. fluorescens genomes carry numerous complex repetitive DNA sequences, some resembling Miniature Inverted-repeat Transposable Elements (MITEs). In SBW25, repeat density and distribution revealed 'repeat deserts' lacking repeats, covering approximately 40% of the genome. P. fluorescens genomes are highly diverse. Strain-specific regions around the replication terminus suggest genome compartmentalization. The genomic heterogeneity among the three strains is reminiscent of a species complex rather than a single species. That 42% of plant-inducible genes were not shared by all strains reinforces this conclusion and shows that ecological success requires specialized and core functions. The diversity also indicates the significant size of genetic information within the Pseudomonas pan genome.

  10. Isolation of Fusarium fujikuroi antagonistic bacteria and cloning of its ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-01

    Dec 1, 2009 ... effects of volatile metabolites produced by antagonistic P. fluorescens found in the isolates inhibited growth of F. fujikuroi in vitro. ... secondary metabolites play critical roles in many aspects of bacterium-host interactions. ... Nocardia, Sorangium, Brevibacterium, and Burkholderia. (Mavrodi et al., 2006; ...

  11. Characterisation of the thermostable protease AprX in strains of Pseudomonas fluorescens and impact on the shelf-life of dairy products: preliminary results

    Directory of Open Access Journals (Sweden)

    Nadia Andrea Andreani

    2016-12-01

    Full Text Available Bacterial proteases are involved in food spoilage and shelf-life reduction. Among the bacterial proteases, a predominant role in spoilage of dairy products seems to be played by the thermostable metallo-protease AprX, which is produced by various strains of Pseudomonas fluorescens. Differences in AprX enzyme activity among different strains were highlighted, but the most proteolytic strains were not identified. In this study, the presence of the aprX gene was evaluated in 69 strains isolated from food matrices and 18 reference strains belonging to the P. fluorescens group, which had been previously typed by the multi locus sequence typing method. Subsequently, a subset of reference strains was inoculated in ultra-high temperature milk, and the expression of the aprX gene was evaluated at 22 and 6°C. On the same milk samples, the proteolytic activity was then evaluated through Azocasein and trinitrobenzenesulfonic acid solution assays. Finally, to assess the applicability of the former assay directly on dairy products the proteolityc activity was tested on industrial ricotta samples using the Azocasein assay. These results demonstrate the spread of aprX gene in most strains tested and the applicability of Azocasein assay to monitor the proteolytic activity in dairy products.

  12. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Maldonado-González, M. Mercedes; Bakker, Peter A. H. M.; Prieto, Pilar; Mercado-Blanco, Jesús

    2015-01-01

    The effective management of Verticillium wilts (VW), diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control VW of olive caused by the highly virulent, defoliating (D) pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V. dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i) olive D and non-defoliating V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii) strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii) strain PICF7 controls VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. A. thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7. PMID:25904904

  13. Sequencing and Analysis of the Pseudomonas fluorescens GcM5-1A Genome: A Pathogen Living in the Surface Coat of Bursaphelenchus xylophilus.

    Directory of Open Access Journals (Sweden)

    Kai Feng

    Full Text Available It is known that several bacteria are adherent to the surface coat of pine wood nematode (Bursaphelenchus xylophilus, but their function and role in the pathogenesis of pine wilt disease remains debatable. The Pseudomonas fluorescens GcM5-1A is a bacterium isolated from the surface coat of pine wood nematodes. In previous studies, GcM5-1A was evident in connection with the pathogenicity of pine wilt disease. In this study, we report the de novo sequencing of the GcM5-1A genome. A 600-Mb collection of high-quality reads was obtained and assembled into sequence contigs spanning a 6.01-Mb length. Sequence annotation predicted 5,413 open reading frames, of which 2,988 were homologous to genes in the other four sequenced P. fluorescens isolates (SBW25, WH6, Pf0-1 and Pf-5 and 1,137 were unique to GcM5-1A. Phylogenetic studies and genome comparison revealed that GcM5-1A is more closely related to SBW25 and WH6 isolates than to Pf0-1 and Pf-5 isolates. Towards study of pathogenesis, we identified 79 candidate virulence factors in the genome of GcM5-1A, including the Alg, Fl, Waa gene families, and genes coding the major pathogenic protein fliC. In addition, genes for a complete T3SS system were identified in the genome of GcM5-1A. Such systems have proved to play a critical role in subverting and colonizing the host organisms of many gram-negative pathogenic bacteria. Although the functions of the candidate virulence factors need yet to be deciphered experimentally, the availability of this genome provides a basic platform to obtain informative clues to be addressed in future studies by the pine wilt disease research community.

  14. Transport of a genetically modified Pseudomonas fluorescens and its parent strain through undisturbed tropical soil cores

    NARCIS (Netherlands)

    Guimaraes, V.F.; Cruz, I.V.; Hagler, A.N.; Mendonca-Hagler, L.C.; Elsas, van J.D.

    1997-01-01

    The transport of a genetically modified strain of Pseudomonas fluorescens, BR12, and its parent, BR5, was studied after irrigation of undisturbed clayey and sandy soil cores, simulating heavy tropical rainfall (56.6 mm/h). Vertical transport of both inoculant strains was detected in all soil cores.

  15. Inhibition of Vibrio anguillarum by Pseudomonas fluorescens AH2, a possible probiotic treatment of fish

    DEFF Research Database (Denmark)

    Gram, Lone; Melchiorsen, Jette; Spanggaard, Bettina

    1999-01-01

    To study the possible use of probiotics in fish farming, we evaluated the in vitro and in vivo antagonism of antibacterial strain Pseudomonas fluorescens strain AH2 against the fish- pathogenic bacterium Vibrio anguillarum. As iron is important in virulence and bacterial interactions, the effect....... fluorescens AH2 inhibited the growth of V. anguillarum during coculture, independently of the iron concentration, when the initial count of the antagonist was 100 to 1,000 times greater that of the fish pathogen. These in vitro results were successfully repeated in vivo. A probiotic effect in vivo was tested...... by exposing rainbow trout (Oncorynchus mykiss Walbaum) to P. fluorescens AH2 at a density of 10(5) CFU/ml for 5 days before a challenge with V. anguillarum at 10(4) to 10(5) CFU/ml for 1 h. Some fish were also exposed to P. fluorescens AH2 at 10(7) CFU/ml during the 1-h infection. The combined probiotic...

  16. 76 FR 52871 - Pseudomonas fluorescens Strain CL145A; Exemption From the Requirement of a Tolerance

    Science.gov (United States)

    2011-08-24

    ... fluorescens-contaminated blood product was used for transfusions. In the past, EPA has registered several... and select ``Test Methods and Guidelines.'' C. How can I file an objection or hearing request? Under... following methods: Federal eRulemaking Portal: http://www.regulations.gov . Follow the on-line instructions...

  17. Inactivation of Pseudomonas fluorescens in skim milk by combinations of pulsed electric fields and organic acids.

    Science.gov (United States)

    Fernández-Molina, Juan J; Altunakar, Bilge; Bermúdez-Aguirre, Daniela; Swanson, Barry G; Barbosa-Cánovas, Gustavo V

    2005-06-01

    Pseudomonas fluorescens suspended in skim milk was inactivated by application of pulsed electric fields (PEF) either alone or in combination with acetic or propionic acid. The initial concentration of microorganisms ranged from 10(5) to 10(6) CFU/ml. Addition of acetic acid and propionic acid to skim milk inactivated 0.24 and 0.48 log CFU/ml P. fluorescens, respectively. Sets of 10, 20, and 30 pulses were applied to the skim milk using exponentially decaying pulses with pulse lengths of 2 micros and pulse frequencies of 3 Hz. Treatment temperature was maintained between 16 and 20 degrees C. In the absence of organic acids, PEF treatment of skim milk at field intensities of 31 and 38 kV/cm reduced P. fluorescens populations by 1.0 to 1.8 and by 1.2 to 1.9 log CFU/ml, respectively. Additions of acetic and propionic acid to the skim milk in a pH range of 5.0 to 5.3 and PEF treatment at 31, 33, and 34 kV/cm, and 36, 37, and 38 kV/cm reduced the population of P. fluorescens by 1.4 and 1.8 log CFU/ml, respectively. No synergistic effect resulted from the combination of PEF with acetic or propionic acid.

  18. Effects of gamma irradiation on the survival of Pseudomonas fluorescens inoculated on romaine lettuce

    Science.gov (United States)

    Irradiation of fresh fruits and vegetables has been utilized as a post-harvest intervention measure for inactivation of microbial pathogens. Pseudomonas fluorescens 2-79, Q8R1, Q287 are non-plant pathogenic, non-pectolytic strains of a potential biocontrol agent. We tested the sensitivity of these s...

  19. Sensitivity of Pseudomonas fluorescens to gamma irradiation following surface inoculations on romaine lettuce and baby spinach

    Science.gov (United States)

    Irradiation of fresh fruits and vegetables is a post-harvest intervention measure often used to inactivate pathogenic food-borne microbes. We evaluated the sensitivity of Pseudomonas fluorescens strains (2-79, Q8R1, Q287) to gamma irradiation following surface inoculations on romaine lettuce and spi...

  20. Evolutionary history of the phl gene cluster in the plant-associated bacterium Pseudomonas fluorescens

    NARCIS (Netherlands)

    Moynihan, J.A.; Morrissey, J.P.; Coppoolse, E.; Stiekema, W.J.; O'Gara, F.; Boyd, E.F.

    2009-01-01

    Pseudomonas fluorescens is of agricultural and economic importance as a biological control agent largely because of its plant-association and production of secondary metabolites, in particular 2, 4-diacetylphloroglucinol (2, 4-DAPG). This polyketide, which is encoded by the eight gene phl cluster,

  1. Improved Performance of Pseudomonas fluorescens lipase by covalent immobilization onto Amberzyme

    NARCIS (Netherlands)

    Aslan, Yakup; Handayani, Nurrahmi; Stavila, Erythrina; Loos, Katja

    2013-01-01

    Objective: In this study, the conditions of covalent immobilization of Pseudomonas fluorescens lipase onto an oxirane-activated support (Amberzyme) were optimized to obtain a high activity yield. Furthermore, the operational and storage stabilities of immobilized lipase were tested. Methods: Optimum

  2. Expression analysis of the gacS mutant of Pseudomonas fluorescens SBW25

    NARCIS (Netherlands)

    Cheng, Xu; Bruijn, de Irene; Voort, van der M.; Raaijmakers, Jos

    2013-01-01

    Pseudomonas species are ubiquitous in plant-associated environments and produce an array of volatiles, enzymes and antimicrobials. The biosynthesis of many metabolites is regulated by the GacS/GacA two-component regulatory system. Transcriptome analysis of Pseudomonas fluorescens SBW25 revealed that

  3. Water flow induced transport of Pseudomonas fluorescens cells through soil columns as affected by inoculant treatment

    NARCIS (Netherlands)

    Hekman, W.E.; Heijnen, C.E.; Trevors, J.T.; Elsas, van J.D.

    1994-01-01

    Water flow induced transport of Pseudomonas fluorescens cells through soil columns was measured as affected by the inoculant treatment. Bacterial cells were introduced into the topsoil of columns, either encapsulated in alginate beads of different types or mixed with bentonite clay in concentrations

  4. Interactions of trivalent and tetravalent heavy metal-siderophore complexes with pseudomonas fluorescens

    International Nuclear Information System (INIS)

    Yoshida, T.; Ozaki, T.; Ohnuki, T.; Francis, A.J.

    2004-01-01

    We investigated the interactions of the Fe(III)-, Eu(III)-, and Hf(IV)-desferrioxamine B (DFO) complexes with the Gram-negative aerobic bacterium Pseudomonas fluorescens. Potentiometric titration of 1:1 Fe(III)-, Eu(III)-, and Hf(IV)-DFO complexes showed that Hf(IV) formed a strong complex with DFO whose stability was comparable to that of the Fe(III)-DFO complex, while Eu(III) formed a weaker one. DFO in a growth medium was not degraded by P. fluorescens. Contact of P. fluorescens cells with the Fe(III)-, Eu(III)-, and Hf(IV)-DFO complexes at pH 4-9 revealed that there was negligible adsorption of Hf(IV) and Fe(III), whereas Eu(III) was dissociated from DFO and was readily adsorbed by the cells. These results suggest that Fe(III) and Hf(IV) form stable complexes with DFO and are not adsorbed by P. fluorescens cells. Europium(III) forms a weaker complex with DFO than Fe(III) and Hf(IV) do and its DFO complex is readily dissociated in the presence of the cells. (orig.)

  5. Photocatalytic disinfection of spoilage bacteria Pseudomonas fluorescens and Macrococcus caseolyticus by nano-TiO2

    Science.gov (United States)

    Photocatalytic disinfection of spoilage bacteria gram-negative (G-) P. fluorescens and gram-positive (G+) M. caseolyticus by nano-TiO2 under different experimental conditions and the disinfection mechanism were investigated. The experimental conditions included the initial bacterial populations, nan...

  6. Investigation of Pseudomonas fluorescens strain 3JW1 on preventing and reducing aflatoxin contaminations in peanuts.

    Directory of Open Access Journals (Sweden)

    Xiaona Yang

    Full Text Available Pseudomonas fluorescens strain 3JW1, which has a broad-spectrum antimicrobial activity, was studied to investigate whether it affects the amounts of aflatoxin B1 (AFB1 produced by Aspergillus flavus. It was found that the bacterium reduced the amounts of AFB1 in potato dextrose broth (PDB and peanut medium by 97.8% and 99.4%, respectively. It also reduced AFB1 by ~183 μg/kg (55.8% when applied onto peanut kernels. This strain reduced AFB1 via three mechanisms. First, it significantly inhibited A. flavus growth; second, our data showed that strain 3JW1 inhibits aflatoxin biosynthesis by A. flavus; and third, P. fluorescens strain 3JW1 is capable of degrading AFB1 at a rate as high as 88.3% in 96 hours. This is the first report demonstrating that Pseudomonas fluorescens can reduce toxin contamination caused by A. flavus on peanut kernels. Our findings indicate that P. fluorescens strain 3JW1 had multiple effects including reducing A. flavus infection and aflatoxin contamination. And the results also highlight the potential applications of the strain 3JW1 for the biological control of aflatoxin contamination in peanuts and other susceptible crops.

  7. Switching Catalysis from Hydrolysis to Perhydrolysis in Pseudomonas fluorescens Esterase

    Energy Technology Data Exchange (ETDEWEB)

    Yin, D.; Bernhardt, P; Morley, K; Jiang, Y; Cheeseman, J; Purpero, V; Schrag, J; Kazlauskas, R

    2010-01-01

    Many serine hydrolases catalyze perhydrolysis, the reversible formation of peracids from carboxylic acids and hydrogen peroxide. Recently, we showed that a single amino acid substitution in the alcohol binding pocket, L29P, in Pseudomonas fluorescens (SIK WI) aryl esterase (PFE) increased the specificity constant of PFE for peracetic acid formation >100-fold [Bernhardt et al. (2005) Angew. Chem., Int. Ed. 44, 2742]. In this paper, we extend this work to address the three following questions. First, what is the molecular basis of the increase in perhydrolysis activity? We previously proposed that the L29P substitution creates a hydrogen bond between the enzyme and hydrogen peroxide in the transition state. Here we report two X-ray structures of L29P PFE that support this proposal. Both structures show a main chain carbonyl oxygen closer to the active site serine as expected. One structure further shows acetate in the active site in an orientation consistent with reaction by an acyl-enzyme mechanism. We also detected an acyl-enzyme intermediate in the hydrolysis of {var_epsilon}-caprolactone by mass spectrometry. Second, can we further increase perhydrolysis activity? We discovered that the reverse reaction, hydrolysis of peracetic acid to acetic acid and hydrogen peroxide, occurs at nearly the diffusion limited rate. Since the reverse reaction cannot increase further, neither can the forward reaction. Consistent with this prediction, two variants with additional amino acid substitutions showed 2-fold higher k{sub cat}, but K{sub m} also increased so the specificity constant, k{sub cat}/K{sub m}, remained similar. Third, how does the L29P substitution change the esterase activity? Ester hydrolysis decreased for most esters (75-fold for ethyl acetate) but not for methyl esters. In contrast, L29P PFE catalyzed hydrolysis of {var_epsilon}-caprolactone five times more efficiently than wild-type PFE. Molecular modeling suggests that moving the carbonyl group closer to the

  8. Analysis of Bacillus thuringiensis Population Dynamics and Its Interaction With Pseudomonas fluorescens in Soil

    Science.gov (United States)

    Rojas-Ruiz, Norma Elena; Sansinenea-Royano, Estibaliz; Cedillo-Ramirez, Maria Lilia; Marsch-Moreno, Rodolfo; Sanchez-Alonso, Patricia; Vazquez-Cruz, Candelario

    2015-01-01

    Background: Bacillus thuringiensis is the most successful biological control agent, however, studies so far have shown that B. thuringiensis is very sensitive to environmental factors such as soil moisture and pH. Ultraviolet light from the sun had been considered as the main limiting factor for its persistence in soil and it has recently been shown that the antagonism exerted by other native soil organisms, such as Pseudomonas fluorescens, is a determining factor in the persistence of this bacterium under in vitro culture conditions. Objectives: The aim of the present investigation was to analyze the population dynamics of B. thuringiensis and its interaction with P. fluorescens using microbiological and molecular methods in soil, under different conditions, and to determinate the effect of nutrients and moisture on its interaction. Materials and Methods: The monitoring was performed by microbiological methods, such as viable count of bacteria, and molecular methods such as Polymerase Chain Reaction (PCR) and hybridization, using the direct extraction of DNA from populations of inoculated soil. Results: The analysis of the interaction between B. thuringiensis and P. fluorescens in soil indicated that the disappearance of B. thuringiensis IPS82 is not dependent on the moisture but the composition of nutrients that may be affecting the secretion of toxic compounds in the environment of P. fluorescens. The results showed that the recovered cells were mostly spores and not vegetative cells in all proved treatments. The molecular methods were effective for monitoring bacterial population inoculated in soil. Conclusions: Bacillus thuringiensis is very sensitive to the interaction of P. fluorescens, however is capable to survive in soil due to its capacity of sporulate. Some of the cells in the form of spores germinated and folded slightly and remained in a constant cycle of sporulation and germination. This confirms that B. thuringiensis IPS82 can germinate, grow and

  9. Transcriptomic analysis of the response of Pseudomonas fluorescens to epigallocatechin gallate by RNA-seq.

    Directory of Open Access Journals (Sweden)

    Xiaoxiang Liu

    Full Text Available Epigallocatechin gallate (EGCG is a main constituent of green tea polyphenols that are widely used as food preservatives and are considered to be safe for consumption. However, the underlying antimicrobial mechanism of EGCG and the bacterial response to EGCG are not clearly understood. In the present study, a genome-wide transcriptional analysis of a typical spoilage bacterium, Pseudomonas fluorescens that responded to EGCG was performed using RNA-seq technology. A total of 26,365,414 and 23,287,092 clean reads were generated from P. fluorescens treated with or without 1 mM EGCG and the clean reads were aligned to the reference genome. Differential expression analysis revealed 291 upregulated genes and 134 downregulated genes and the differentially expressed genes (DEGs were verified using RT-qPCR. Most of the DGEs involved in iron uptake, antioxidation, DNA repair, efflux system, cell envelope and cell-surface component synthesis were significantly upregulated by EGCG treatment, while most genes associated with energy production were downregulated. These transcriptomic changes are likely to be adaptive responses of P. fluorescens to iron limitation and oxidative stress, as well as DNA and envelope damage caused by EGCG. The expression of specific genes encoding the extra-cytoplasmic function sigma factor (PvdS, RpoE and AlgU and the two-component sensor histidine kinase (BaeS and RpfG were markedly changed by EGCG treatment, which may play important roles in regulating the stress responses of P. fluorescens to EGCG. The present data provides important insights into the molecular action of EGCG and the possible cross-resistance mediated by EGCG on P. fluorescens, which may ultimately contribute to the optimal application of green tea polyphenols in food preservation.

  10. Study of the Population Dynamics of Listeria Monocytogenes and Pseudomonas Fluorescens in Buffalo Mozzarella by Means of Challenge Testing

    Science.gov (United States)

    Nava, Donatella; Capo, Salvatore; Caligiuri, Vincenzo; Giaccone, Valerio; Biondi, Loredana; Vaccaro, Gerardo Francesco; Guarino, Achille; Capuano, Federico

    2016-01-01

    Campania’s buffalo mozzarella is a greatly appreciated cheese in Italy and worldwide. From a microbiological standpoint, it is a highly perishable food and potentially at risk of contamination by pathogens such as Listeria monocytogenes (L. monocytogenes). The present paper reports the results of a challenge test carried out to assess the population dynamics of L. monocytogenes, alone and in presence of Pseudomonas fluorescens (P. fluorescens), in buffalo mozzarella. For this purpose buffalo mozzarella samples were contaminated with L. monocytogenes alone or combined with P. fluorescens. In samples where L. monocytogenes was inoculated alone, the bacterial load remained unchanged. On the contrary, in samples contaminated with L. monocytogenes and P. fluorescens, the growth of L. monocytogenes increased. PMID:27853707

  11. Study of the population dynamics of Listeria monocytogenes and Pseudomonas fluorescens in buffalo mozzarella by means of challenge testing

    Directory of Open Access Journals (Sweden)

    Donatella Nava

    2016-06-01

    Full Text Available Campania’s buffalo mozzarella is a greatly appreciated cheese in Italy and worldwide. From a microbiological standpoint, it is a highly perishable food and potentially at risk of contamination by pathogens such as Listeria monocytogenes (L. monocytogenes. The present paper reports the results of a challenge test carried out to assess the population dynamics of L. monocytogenes, alone and in presence of Pseudomonas fluorescens (P. fluorescens, in buffalo mozzarella. For this purpose buffalo mozzarella samples were contaminated with L. monocytogenes alone or combined with P. fluorescens. In samples where L. monocytogenes was inoculated alone, the bacterial load remained unchanged. On the contrary, in samples contaminated with L. monocytogenes and P. fluorescens, the growth of L. monocytogenes increased.

  12. Differentiation of isolated native of desulphurizators Pseudomonas by means of the study of the profile of fatty acids

    International Nuclear Information System (INIS)

    Silva Gomez, Edelberto; Morales P, Alicia Lucia; Callejas Castro Solange; Florez Sandoval Maria Cecilia; Rodriguez Wilson

    2000-01-01

    The content of cellular fatty acids was determined by HRGC of twelve Colombian isolated Pseudomonas aeruginosa 17,18, 19, 20, 21, 22 and 103 pseudomonas sp 23,24,25,26 and 27 with desulphurization capacity, pseudomonas aeruginosa ATCC 9027 and 10145, pseudomonas sp ATCC 39327 and pseudomonas fluorescens. Fifty-three different types of fatty acids were found, among saturated and unsaturated of lineal chain, and mainly hydroxy acids and ramified. Of these, 17 have not been described in the literature for this genus. A group of 6 acids was presented with more frequency (15:0; 16:0; 16:1; 17:1; 3-OH 16:0 and 2-OH 15:0) in more than 75% of the pseudomonas studied. The studied microorganisms are related because they share the presence of some characteristic fatty acids, that which allows assuring that they belong to same taxonomic unit. The analysis cluster developed by means of plotting in dendrograms of the qualitative and quantitative contents of the acids fatty totals showed the formation of two attaches, the I conformed by ATCC 39327 and the isolated 17 and 25, and the II by Ps. Fluorescens and the isolated one 27. The dendrogram of the hydroxy acids shows the formation of four attaches, the I attache, (isolated 17 and 20), the II A (isolated 22 and 103), the II B (isolated 27 and ps. fluorescens) and the attache III (isolated 18 and 19). In that of the ramified fatty acids the formation of a main attache is observed conformed by four sub-groups, the IA (isolated 17), the I B (isolated 18 and 24), the I C (isolated 19 and 25 and Ps. fluorescens) and I D (isolated 27). These results show that the isolated 27,25,24, 19, 18 and 17, in their order, have narrow relationship to Ps. fluorescens

  13. Nematicidal protease genes screened from a soil metagenomic library to control Radopholus similis mediated by Pseudomonas fluorescens pf36.

    Science.gov (United States)

    Chen, Deqiang; Wang, Dongwei; Xu, Chunling; Chen, Chun; Li, Junyi; Wu, Wenjia; Huang, Xin; Xie, Hui

    2018-04-01

    Controlling Radopholus similis, an important phytopathogenic nematode, is a challenge worldwide. Herein, we constructed a metagenomic fosmid library from the rhizosphere soil of banana plants, and six clones with protease activity were obtained by functionally screening the library. Furthermore, subclones were constructed using the six clones, and three protease genes with nematicidal activity were identified: pase1, pase4, and pase6. The pase4 gene was successfully cloned and expressed, demonstrating that the protease PASE4 could effectively degrade R. similis tissues and result in nematode death. Additionally, we isolated a predominant R. similis-associated bacterium, Pseudomonas fluorescens (pf36), from 10 R. similis populations with different hosts. The pase4 gene was successfully introduced into the pf36 strain by vector transformation and conjugative transposition, and two genetically modified strains were obtained: p4MCS-pf36 and p4Tn5-pf36. p4MCS-pf36 had significantly higher protease expression and nematicidal activity (p < 0.05) than p4Tn5-pf36 in a microtiter plate assay, whereas p4Tn5-pf36 was superior to p4MCS-pf36 in terms of genetic stability and controlling R. similis in growth pot tests. This study confirmed that R. similis is inhibited by the associated bacterium pf36-mediated expression of nematicidal proteases. Herein, a novel approach is provided for the study and development of efficient, environmentally friendly, and sustainable biocontrol techniques against phytonematodes.

  14. Biodesel Production from Pseudomonas Fluorescens Lp1 Lipase Immobilized on Amino-silane Modified Super Paramagnetic Fe3O4 Nanoparticles

    Science.gov (United States)

    Kanimozhi, S.; Perinbam, K.

    2013-04-01

    An extracellular lipase from Pseudomonas fluorescens Lp1 isolated from oil contaminated soil was immobilized onto amino silane modified superparamagnetic Fe3O4 nanoparticles. The magnetic nanoparticles, magnetite was synthesized chemically by co-precipitation and characterized by Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (FT-IR) and Powder X-ray diffraction studies (XRD). The structure of the synthesized magnetic nanoparticles was uniform, spherical and the size was determined around 31 nm by powder XRD. The biodiesel production mixture was prepared by addition of waste cooking oil, lipase immobilized magnetite and methanol. The transesterified products were analyzed by Gas Liquid chromatography-Mass spectroscopy (GC-MS). The methyl esters such as Oxiraneundecanoic acid, 3-pentyl-methyl ester, Hexadecanoic acid, methyl ester and 10-Octadecenoic acid, methyl ester were obtained. The study experimentally proved the use of amino silane modified superparamagnetic Fe3O4 nanoparticles in biodiesel production from waste cooking oil.

  15. Biodesel Production from Pseudomonas Fluorescens Lp1 Lipase Immobilized on Amino-silane Modified Super Paramagnetic Fe3O4 Nanoparticles

    International Nuclear Information System (INIS)

    Kanimozhi, S; Perinbam, K

    2013-01-01

    An extracellular lipase from Pseudomonas fluorescens Lp1 isolated from oil contaminated soil was immobilized onto amino silane modified superparamagnetic Fe 3 O 4 nanoparticles. The magnetic nanoparticles, magnetite was synthesized chemically by co-precipitation and characterized by Scanning Electron Microscopy (SEM), Fourier Transformed Infrared Spectroscopy (FT-IR) and Powder X-ray diffraction studies (XRD). The structure of the synthesized magnetic nanoparticles was uniform, spherical and the size was determined around 31 nm by powder XRD. The biodiesel production mixture was prepared by addition of waste cooking oil, lipase immobilized magnetite and methanol. The transesterified products were analyzed by Gas Liquid chromatography-Mass spectroscopy (GC-MS). The methyl esters such as Oxiraneundecanoic acid, 3-pentyl-methyl ester, Hexadecanoic acid, methyl ester and 10-Octadecenoic acid, methyl ester were obtained. The study experimentally proved the use of amino silane modified superparamagnetic Fe 3 O 4 nanoparticles in biodiesel production from waste cooking oil.

  16. Effect of Naphthalene and Salicylate Analogues on the Bioluminescence of Bioreporter Pseudomonas Fluorescens HK44.

    Czech Academy of Sciences Publication Activity Database

    Trögl, Josef; Kuncová, Gabriela; Kubicová, L.; Pařík, P.; Hálová, Jaroslava; Demnerová, K.; Ripp, S.; Sayler, G. S.

    2007-01-01

    Roč. 52, 1 (2007) , s. 3-14 ISSN 0015-5632 R&D Projects: GA ČR(CZ) GA104/05/2637; GA ČR(CZ) GA203/06/1244 Institutional research plan: CEZ:AV0Z40720504; CEZ:AV0Z40320502 Keywords : pseudomonas fluorescens HK44 * bioluminescence * bioluminescence Subject RIV: CE - Biochemistry Impact factor: 0.989, year: 2007

  17. Selectivity of Whole Cell Optical Biosensor with Immobilized Bioreporter Pseudomonas Fluorescens HK44

    Czech Academy of Sciences Publication Activity Database

    Trögl, Josef; Ripp, S.; Kuncová, Gabriela; Sayler, G. S.; Churavá, Alena; Pařík, P.; Demnerová, K.; Hálová, Jaroslava; Kubicová, L.

    2005-01-01

    Roč. 107, č. 1 (2005), s. 98-103 ISSN 0925-4005. [European Conference on Optical Chemical Sensors and Biosensors EUROPT(R)ODE /7./. Madrid, 04.04.2004-07.04.2004] R&D Projects: GA ČR(CZ) GA104/01/0461 Institutional research plan: CEZ:AV0Z40720504 Keywords : biosensor * Pseudomonas fluorescens HK44 * naphthalene Subject RIV: CE - Biochemistry Impact factor: 2.646, year: 2005

  18. Controlled-release fertilizers combined with Pseudomonas fluorescens rhizobacteria inoculum improve growth in Pinus halepensis seedlings

    OpenAIRE

    Dominguez-Nuñez JA; Delgado-Alvez D; Berrocal-Lobo M; Anriquez A; Albanesi A

    2015-01-01

    Pinus halepensis seedlings are currently used to regenerate arid Mediterranean regions. Optimized methods for seedling fertilization in nurseries improve plant growth and are essential for successful reforestation. Previously, we showed that inoculation of P. halepensis seedlings with Pseudomonas fluorescens CECT 844 rhizobacteria improved plant growth and N uptake. The aim of this study was to determine the physiological and morphological response of P. halepensis seedlings to a combined tre...

  19. Identification and characterization of a novel nitrilase from Pseudomonas fluorescens Pf-5.

    Science.gov (United States)

    Kim, Jung-Soo; Tiwari, Manish Kumar; Moon, Hee-Jung; Jeya, Marimuthu; Ramu, Thangadurai; Oh, Deok-Kun; Kim, In-Won; Lee, Jung-Kul

    2009-05-01

    Nitrile groups are catabolized to the corresponding acid and ammonia through one-step reaction involving a nitrilase. Here, we report the use of bioinformatic and biochemical tools to identify and characterize the nitrilase (NitPf5) from Pseudomonas fluorescens Pf-5. The nitPf5 gene was identified via sequence analysis of the whole genome of P. fluorescens Pf-5 and subsequently cloned and overexpressed in Escherichia coli. DNA sequence analysis revealed an open-reading frame of 921 bp, capable of encoding a polypeptide of 307 amino acids residues with a calculated isoelectric point of pH 5.4. The enzyme had an optimal pH and temperature of 7.0 degrees C and 45 degrees C, respectively, with a specific activity of 1.7 and 1.9 micromol min(-1) mg protein(-1) for succinonitrile and fumaronitrile, respectively. The molecular weight of the nitrilase as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography was 33,000 and 138,000 Da, respectively, suggesting that the enzyme is homotetrameric. Among various nitriles, dinitriles were the preferred substrate of NitPf5 with a K (m) = 17.9 mM and k (cat)/K (m) = 0.5 mM(-1) s(-1) for succinonitrile. Homology modeling and docking studies of dinitrile and mononitrile substrate into the active site of NitPf5 shed light on the substrate specificity of NitPf5. Although nitrilases have been characterized from several other sources, P. fluorescens Pf-5 nitrilase NitPf5 is distinguished from other nitrilases by its high specific activity toward dinitriles, which make P. fluorescens NitPf5 useful for industrial applications, including enzymatic synthesis of various cyanocarboxylic acids.

  20. Sorption of Eu(III) on Pseudomonas fluorescens in the presence of citric acid

    International Nuclear Information System (INIS)

    Suzuki, Yoshinori; Tsushima, Satoru; Yamamoto, Ichiro; Nankawa, Takuya; Yoshida, Takahiro; Ozaki, Takuo; Ohnuki, Toshihiko; Francis, Arokiasamy J.; Enokida, Youichi

    2005-01-01

    We studied the sorption of Eu(III) on Pseudomonas fluorescens in the absence and presence of citric acid by a batch method. The cells were placed in a solution containing 2 μM of Eu(III) and 0, 100, or 1000 μM of citric acid at pH 3 9 for 5 hours. In the absence of citric acid, almost 100% of Eu(III) was sorbed on P. fluorescens at pHs below 7; above 7, sorption decreased with an increase in pH. The time course of Eu(III) sorption on P. fluorescens showed that a fraction of it was desorbed into the solution at alkaline pHs, suggesting that the bacterium may release some exudates. With citric acid present, we found that at higher concentrations there was lower sorption of Eu(III), reflecting the formation of Eu(III)-citrate complexes with the Eu(III)-cell-surface complexes. This decrease in Eu(III) sorption was significant in alkaline pHs. These findings suggest that citric acid which is ubiquitously found in the environment enhances migration of trivalent actinides in the alkaline environment. (author)

  1. Impact of a Recombinant Biocontrol Bacterium, Pseudomonas fluorescens pc78, on Microbial Community in Tomato Rhizosphere

    Directory of Open Access Journals (Sweden)

    Hyun Gi Kong

    2016-04-01

    Full Text Available Pseudomonas fluorescens pc78 is an effective biocontrol agent for soil-borne fungal diseases. We previously constructed a P43-gfp tagged biocontrol bacteria P. fluorescens pc78-48 to investigate bacterial traits in natural ecosystem and the environmental risk of genetically modified biocontrol bacteria in tomato rhizosphere. Fluctuation of culturable bacteria profile, microbial community structure, and potential horizontal gene transfer was investigated over time after the bacteria treatment to the tomato rhizosphere. Tagged gene transfer to other organisms such as tomato plants and bacteria cultured on various media was examined by polymerase chain reaction, using gene specific primers. Transfer of chromosomally integrated P43-gfp from pc78 to other organisms was not apparent. Population and colony types of culturable bacteria were not significantly affected by the introduction of P. fluorescens pc78 or pc78-48 into tomato rhizosphere. Additionally, terminal restriction fragment length polymorphism profiles were investigated to estimate the influence on the microbial community structure in tomato rhizosphere between non-treated and pc78-48-treated samples. Interestingly, rhizosphere soil treated with strain pc78-48 exhibited a significantly different bacterial community structure compared to that of non-treated rhizosphere soil. Our results suggest that biocontrol bacteria treatment influences microbial community in tomato rhizosphere, while the chromosomally modified biocontrol bacteria may not pose any specific environmental risk in terms of gene transfer.

  2. Impact of a Recombinant Biocontrol Bacterium, Pseudomonas fluorescens pc78, on Microbial Community in Tomato Rhizosphere.

    Science.gov (United States)

    Kong, Hyun Gi; Kim, Nam Hee; Lee, Seung Yeup; Lee, Seon-Woo

    2016-04-01

    Pseudomonas fluorescens pc78 is an effective biocontrol agent for soil-borne fungal diseases. We previously constructed a P43-gfp tagged biocontrol bacteria P. fluorescens pc78-48 to investigate bacterial traits in natural ecosystem and the environmental risk of genetically modified biocontrol bacteria in tomato rhizosphere. Fluctuation of culturable bacteria profile, microbial community structure, and potential horizontal gene transfer was investigated over time after the bacteria treatment to the tomato rhizosphere. Tagged gene transfer to other organisms such as tomato plants and bacteria cultured on various media was examined by polymerase chain reaction, using gene specific primers. Transfer of chromosomally integrated P43-gfp from pc78 to other organisms was not apparent. Population and colony types of culturable bacteria were not significantly affected by the introduction of P. fluorescens pc78 or pc78-48 into tomato rhizosphere. Additionally, terminal restriction fragment length polymorphism profiles were investigated to estimate the influence on the microbial community structure in tomato rhizosphere between non-treated and pc78-48-treated samples. Interestingly, rhizosphere soil treated with strain pc78-48 exhibited a significantly different bacterial community structure compared to that of non-treated rhizosphere soil. Our results suggest that biocontrol bacteria treatment influences microbial community in tomato rhizosphere, while the chromosomally modified biocontrol bacteria may not pose any specific environmental risk in terms of gene transfer.

  3. PRODUCTION OF PROTEASE AND UREASE BY KEROSENE UTILIZING FLUORESCENT PSEUDOMONADS ISOLATED FROM LOCAL RED LATIRITE SOIL

    OpenAIRE

    V. UMAMAHESWARA RAO; N. JYOTHI

    2013-01-01

    The present work relates to a simple, safe, and efficient process for the complete utilization of kerosene usingfluorescent pseudomonads. Fluorescent pseudomonads used in this study were isolated from local red soilcollected at Acharya Nagarjuna University Campus, Guntur Dt., (AP) India. The isolates were identified asPseudomonas aeruginosa, Pseudomonas aureofaciens, Pseudomonas putida and Pseudomonas fluorescens onthe basis of biochemical characteristics. The isolates were screened for their...

  4. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Directory of Open Access Journals (Sweden)

    M. Mercedes eMaldonado-González

    2015-04-01

    Full Text Available The effective management of Verticillium wilts, diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control Verticillium wilt of olive caused by the highly-virulent, defoliating (D pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V.dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i olive D and non-defoliating (ND V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii strain PICF7 controls Verticillium wilt (VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. Arabidopsis thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7.

  5. Genome Analysis of Pseudomonas fluorescens PCL1751: A Rhizobacterium that Controls Root Diseases and Alleviates Salt Stress for Its Plant Host.

    Directory of Open Access Journals (Sweden)

    Shu-Ting Cho

    Full Text Available Pseudomonas fluorescens PCL1751 is a rod-shaped Gram-negative bacterium isolated from the rhizosphere of a greenhouse-grown tomato plant in Uzbekistan. It controls several plant root diseases caused by Fusarium fungi through the mechanism of competition for nutrients and niches (CNN. This mechanism does not rely on the production of antibiotics, so it avoids the concerns of resistance development and is environmentally safe. Additionally, this bacterium promotes plant growth by alleviating salt stress for its plant host. To investigate the genetic mechanisms that may explain these observations, we determined the complete genome sequence of this bacterium, examined its gene content, and performed comparative genomics analysis with other Pseudomonas strains. The genome of P. fluorescens PCL1751 consisted of one circular chromosome that is 6,143,950 base-pairs (bp in size; no plasmid was found. The annotation included 19 rRNA, 70 tRNA, and 5,534 protein-coding genes. The gene content analysis identified a large number of genes involved in chemotaxis and motility, colonization of the rhizosphere, siderophore biosynthesis, and osmoprotectant production. In contrast, the pathways involved in the biosynthesis of phytohormones or antibiotics were not found. Comparison with other Pseudomonas genomes revealed extensive variations in their genome size and gene content. The presence and absence of secretion system genes were highly variable. As expected, the synteny conservation among strains decreased as a function of phylogenetic divergence. The integration of prophages appeared to be an important driver for genome rearrangements. The whole-genome gene content analysis of this plant growth-promoting rhizobacterium (PGPR provided some genetic explanations to its phenotypic characteristics. The extensive and versatile substrate utilization pathways, together with the presence of many genes involved in competitive root colonization, provided further support

  6. Broad-range antagonistic rhizobacteria Pseudomonas fluorescens and Serratia plymuthica suppress Agrobacterium crown gall tumours on tomato plants.

    Science.gov (United States)

    Dandurishvili, N; Toklikishvili, N; Ovadis, M; Eliashvili, P; Giorgobiani, N; Keshelava, R; Tediashvili, M; Vainstein, A; Khmel, I; Szegedi, E; Chernin, L

    2011-01-01

    To examine the biocontrol activity of broad-range antagonists Serratia plymuthica IC1270, Pseudomonas fluorescens Q8r1-96 and P. fluorescens B-4117 against tumourigenic strains of Agrobacterium tumefaciens and A. vitis. Under greenhouse conditions, the antagonists, applied via root soak prior to injecting Agrobacterium strains into the wounded stems, significantly suppressed tumour development on tomato seedlings. A derivative of P. fluorescens Q8r1-96 tagged with a gfp reporter, as well as P. fluorescens B-4117 and S. plymuthica IC1270 marked with rifampicin resistance, stably persisted in tomato tissues for at least 1 month. Mutants of P. fluorescens Q8r1-96 and S. plymuthica IC1270 deficient in 2,4-diacetylphloroglucinol or pyrrolnitrin production, respectively, also proficiently suppressed the tumour development, indicating that these antibiotics are not responsible for the observed biocontrol effect on crown gall disease. The volatile organic compounds (VOCs) produced by the tested P. fluorescens and S. plymuthica strains inhibited the growth of A. tumefaciens and A. vitis strains in vitro. Solid-phase microextraction-gas chromatography-mass spectrometry analysis revealed dimethyl disulfide (DMDS) as the major headspace volatile produced by S. plymuthica IC1270; it strongly suppressed Agrobacterium growth in vitro and was emitted by tomato plants treated with S. plymuthica IC1270. 1-Undecene was the main volatile emitted by the examined P. fluorescens strains, with other volatiles, including DMDS, being detected in only relatively low quantities. S. plymuthica IC1270, P. fluorescens B-4117 and P. fluorescens Q8r1-96 can be used as novel biocontrol agents of pathogenic Agrobacterium. VOCs, and specifically DMDS, might be involved in the suppression of oncogenicity in tomato plants. However, the role of specific volatiles in the biocontrol activity remains to be elucidated. The advantage of applying these antagonists lies in their multiple activities against a

  7. Exposure-related effects of formulated Pseudomonas fluorescens strain CL145A to glochidia from seven unionid mussel species

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Severson, Todd J.; Schreier, Theresa M.; Mayer, Denise A.; Aloisi, Douglas B.; Eckert, Nathan L.

    2015-01-01

    The study was completed to evaluate the exposure-related effects of a biopesticide for dreissenid mussel (Dreissena polymorpha, zebra mussel and Dreissena rostriformis bugensis, quagga mussel) control on glochidia from unionid mussels endemic to the Great Lakes and Upper Mississippi River Basins. The commercially prepared biopesticide was either a spray-dried powder (SDP) or freeze-dried powder (FDP) formulation of Pseudomonas fluorescens, strain CL145A. Glochidia of the unionid mussel species Lampsilis cardium, Lampsilis siliquoidea,Lampsilis higginsii, Ligumia recta, Obovaria olivaria, and Actinonaias ligamentina were exposed to SDP-formulated P. fluorescens andLampsilis cardium and Megalonaias nervosa were exposed to FDP-formulated P. fluorescens.

  8. Antigen 43 from Escherichia coli induces inter- and intraspecies cell aggregation and changes in colony morphology of Pseudomonas fluorescens

    DEFF Research Database (Denmark)

    Kjærgaard, Kristian; Schembri, Mark; Hasman, Henrik

    2000-01-01

    with a distinct frizzy colony morphology in E. coli. Here we show that Ag43 can be expressed in a functional form on the surface of the environmentally important Pseudomonas fluorescens strain SBW25 with ensuing cell aggregation and frizzy colony types. Using green fluorescence protein-tagged cells, we......Antigen 43 (Ag43) is a surface-displayed autotransporter protein of Escherichia coli. By virtue of its self-association characteristics, this protein is able to mediate autoaggregation and flocculation off. coli cells in static cultures. Additionally, surface display of Ag43 is associated...... demonstrate that Ag43 can be used as a tool to provide interspecies cell aggregation between E. coli and P. fluorescens. Furthermore, Ag43 expression enhances biofilm formation in P. fluorescens to glass surfaces. The versatility of this protein was also reflected in Ag43 surface display in a variety of other...

  9. Supramolecular Structure and Functional Analysis of the Type III Secretion System in Pseudomonas fluorescens 2P24.

    Science.gov (United States)

    Liu, Ping; Zhang, Wei; Zhang, Li-Qun; Liu, Xingzhong; Wei, Hai-Lei

    2015-01-01

    The type III secretion system (T3SS) of plant and animal bacterial pathogens directs the secretion and injection of proteins into host cells. Some homologous genes of T3SS were found also in non-pathogenic bacteria, but the organization of its machinery and basic function are still unknown. In this study, we identified a T3SS gene cluster from the plant growth-promoting Pseudomonas fluorescens 2P24 and isolated the corresponding T3SS apparatus. The T3SS gene cluster of strain 2P24 is similar organizationally to that of pathogenic P. syringae, except that it lacks the regulator hrpR and the hrpK1 and hrpH genes, which are involved in translocation of proteins. Electron microscopy revealed that the T3SS supramolecular structure of strain 2P24 was comprised of two distinctive substructures: a long extracellular, filamentous pilus, and a membrane-embedded base. We show that strain 2P24 deploys a harpin homolog protein, RspZ1, to elicit a hypersensitive response when infiltrated into Nicotiana tabacum cv. xanthi leaves with protein that is partially purified, and by complementing the hrpZ1 mutation of pHIR11. The T3SS of strain 2P24 retained ability to secrete effectors, whereas its effector translocation activity appeared to be excessively lost. Mutation of the rscC gene from 2P24 T3SS abolished the secretion of effectors, but the general biocontrol properties were unaffected. Remarkably, strain 2P24 induced functional MAMP-triggered immunity that included a burst of reactive oxygen species, strong suppression of challenge cell death, and disease expansion, while it was not associated with the secretion functional T3SS.

  10. Supramolecular structure and functional analysis of the type III secretion system in Pseudomonas fluorescens 2P24

    Directory of Open Access Journals (Sweden)

    Ping eLiu

    2016-01-01

    Full Text Available The type III secretion system (T3SS of plant and animal bacterial pathogens directs the secretion and injection of proteins into host cells. Some homologous genes of T3SS were found also in nonpathogenic bacteria, but the organization of its machinery and basic function are still unknown. In this study, we identified a T3SS gene cluster from the plant growth-promoting Pseudomonas fluorescens 2P24 and isolated the corresponding T3SS apparatus. The T3SS gene cluster of strain 2P24 is similar organizationally to that of pathogenic P. syringae, except that it lacks the regulator hrpR and the hrpK1 and hrpH genes, which are involved in translocation of proteins. Electron microscopy revealed that the T3SS supramolecular structure of strain 2P24 was comprised of two distinctive substructures: a long extracellular, filamentous pilus and a membrane-embedded base. We show that strain 2P24 deploys a harpin homologue protein, RspZ1, to elicit a hypersensitive response when infiltrated into Nicotiana tabacum cv. xanthi leaves with protein that is partially purified, and by complementing the hrpZ1 mutation of pHIR11. The T3SS of strain 2P24 retained ability to secrete effectors, whereas its effector translocation activity appeared to be excessively lost. Mutation of the rscC gene from 2P24 T3SS abolished the secretion of effectors, but the general biocontrol properties were unaffected. Remarkably, strain 2P24 induced functional MAMP-triggered immunity that included a burst of reactive oxygen species, strong suppression of challenge cell death, and disease expansion, while it was not associated with the secretion functional T3SS.

  11. The Influence of Pseudomonas fluorescens on Corrosion Products of Archaeological Tin-Bronze Analogues

    Science.gov (United States)

    Ghiara, G.; Grande, C.; Ferrando, S.; Piccardo, P.

    2018-01-01

    In this study, tin-bronze analogues of archaeological objects were investigated in the presence of an aerobic Pseudomonas fluorescens strain in a solution, containing chlorides, sulfates, carbonates and nitrates according to a previous archaeological characterization. Classical fixation protocols were employed in order to verify the attachment capacity of such bacteria. In addition, classical metallurgical analytical techniques were used to detect the effect of bacteria on the formation of uncommon corrosion products in such an environment. Results indicate quite a good attachment capacity of the bacteria to the metallic surface and the formation of the uncommon corrosion products sulfates and sulfides is probably connected to the bacterial metabolism.

  12. Exposure-related effects of Pseudomonas fluorescens (Pf-CL145A) on juvenile unionid mussels

    Science.gov (United States)

    Weber, Kerry L.; Luoma, James A.; Mayer, Denise A.; Aloisi, Douglas B.; Eckert, Nathan L.

    2015-01-01

    The exposure-related effects of a commercially prepared spray-dried powder (SDP) or freeze-dried powder (FDP) formulation of Pseudomonas fluorescens (strain CL145A) on the survival of seven species of newly metamorphosed (<72 hours old) freshwater unionid mussels was evaluated. Forty unionid mussels of each species were randomly distributed to test chambers and each species independently exposed for 24 hours to a static dose of either SDP (four species: Lampsilis cardium, Lampsilis siliquoidea, Lampsilis higginsii, andLigumia recta) or FDP (three species: Obovaria olivaria, Actinonaias ligamentina, andMegalonaias nervosa).

  13. Growth of Pseudomonas fluorescens in modified atmosphere packaged tofu.

    Science.gov (United States)

    Stoops, J; Maes, P; Claes, J; Van Campenhout, L

    2012-03-01

    The objective was to study the growth of Pseudomonas in a food product (tofu) where it typically occurs as a spoilage organism, and when this product is stored under modified atmosphere. A Pseudomonas strain was isolated from the endogenous microflora of tofu. Tofu was inoculated with the strain, packaged in different gas conditions (air, 100% N(2), 30% CO(2) /70% N(2) or 100% CO(2)) and stored under refrigerated conditions. Microbial loads and the headspace gas composition were monitored during storage. The strain was capable of growing in atmospheres containing no or limited amounts of oxygen and increased amounts of carbon dioxide. Even when 100% CO(2) was used, growth could not be inhibited completely. in contrast to the general characteristics of the genus Pseudomonas (strictly aerobic, highly sensitive to CO(2)), it should not be expected in the food industry that removing oxygen from the food package and increasing the carbon dioxide content, combined with cold storage, will easily avoid spoilage by Pseudomonas species. Guarantee of hygienic standards and combination of strategies with other microbial growth inhibiting measures should be implemented. © Kempen University College. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.

  14. High pressure inactivation of Pseudomonas in black truffle - comparison with Pseudomonas fluorescens in tryptone soya broth

    Science.gov (United States)

    Ballestra, Patricia; Verret, Catherine; Cruz, Christian; Largeteau, Alain; Demazeau, Gerard; El Moueffak, Abdelhamid

    2010-03-01

    Pseudomonas is one of the most common genera in black Perigord truffle. Its inactivation by high pressure (100-500 MPa/10 min) applied on truffles at sub-zero or low temperatures was studied and compared with those of Pseudomonas fluorescens in tryptone soya broth. Pressurization of truffles at 300 MPa/4 °C reduced the bacterial count of Pseudomonas by 5.3 log cycles. Higher pressures of 400 or 500 MPa, at 4 °C or 20 °C, allowed us to slightly increase the level of destruction to the value of ca. 6.5 log cycles but did not permit us to completely inactivate Pseudomonas. The results showed a residual charge of about 10 CFU/g. Pressure-shift freezing of truffles, which consists in applying a pressure of 200 MPa/-18 °C for 10 min and then quickly releasing this pressure to induce freezing, reduced the population of Pseudomonas by 3.3 log cycles. The level of inactivation was higher than those obtained with conventional freezing. Endogenous Pseudomonas in truffle was shown to be more resistant to high pressure treatments than P. fluorescens used for inoculation of broths.

  15. Compatibility of Azospirillum brasilense and Pseudomonas fluorescens in growth promotion of groundnut ( Arachis hypogea L.

    Directory of Open Access Journals (Sweden)

    ANDHARE A. PRASAD

    Full Text Available ABSTRACT We attempted to study the compatibility among plant beneficial bacteria in the culture level by growing them near in the nutrient agar plates. Among all the bacteria tested, Rhizobium was found to inhibit the growth of other bacteria. From the compatible group of PGPR, we have selected one biofertilizer (Azospirillum brasilense strain TNAU and one biocontrol agent (Pseudomonas fluorescens strain PF1 for further studies in the pot culture. We have also developed a bioformulation which is talc powder based, for individual bacteria and mixed culture. This formulation was used as seed treatment, soil application, seedling root dip and foliar spray in groundnut crop in vitro germination conditions. A. brasilense was found to enhance the tap root growth and P. fluorescens, the lateral root growth. The other growth parameters like shoot growth, number of leaves were enhanced by the combination of both of the bacteria than their individual formulations. Among the method of application tested in our study, soil application was found to be the best in yielding better results of plant growth promotion.

  16. Compatibility of Azospirillum brasilense and Pseudomonas fluorescens in growth promotion of groundnut ( Arachis hypogea L.).

    Science.gov (United States)

    Prasad, Andhare A; Babu, Subramanian

    2017-01-01

    We attempted to study the compatibility among plant beneficial bacteria in the culture level by growing them near in the nutrient agar plates. Among all the bacteria tested, Rhizobium was found to inhibit the growth of other bacteria. From the compatible group of PGPR, we have selected one biofertilizer (Azospirillum brasilense strain TNAU) and one biocontrol agent (Pseudomonas fluorescens strain PF1) for further studies in the pot culture. We have also developed a bioformulation which is talc powder based, for individual bacteria and mixed culture. This formulation was used as seed treatment, soil application, seedling root dip and foliar spray in groundnut crop in vitro germination conditions. A. brasilense was found to enhance the tap root growth and P. fluorescens, the lateral root growth. The other growth parameters like shoot growth, number of leaves were enhanced by the combination of both of the bacteria than their individual formulations. Among the method of application tested in our study, soil application was found to be the best in yielding better results of plant growth promotion.

  17. Survival of a Rifampicin-Resistant Pseudomonas fluorescens Strain in Nine Mollisols

    Directory of Open Access Journals (Sweden)

    Tami L. Stubbs

    2014-01-01

    Full Text Available Pseudomonas fluorescens strain D7 (P.f. D7 is a naturally occurring soil bacterium that shows promise as a biological herbicide to inhibit growth of annual grass weeds, including downy brome (Bromus tectorum L., in crop- and rangelands. Pseudomonas fluorescens strain D7rif (P.f. D7rif is a rifampicin-resistant strain of P.f. D7. One of the greatest obstacles to successful biological weed control is survival of the organism under field conditions. Nine soils in the taxonomic order of Mollisols, collected from downy brome-infested areas of the Western and Central United States, were inoculated with P.f. D7rif and incubated in the laboratory to determine the effects of soil type, soil properties, incubation temperature, and soil water potential on survival of P.f. D7rif over 63 days. Silt loam soils from Lind, Washington, and Moro, Oregon, sustained the highest P.f. D7rif populations, and recovery was the lowest from Pendleton, Oregon soil. Survival and recovery of P.f. D7rif varied with soil type and temperature but not with the two soil water potentials tested. After 63 days, P.f. D7rif was recovered at levels greater than log 5.5 colony forming units (CFU g−1 soil from five of the nine test soils, a level adequate to suppress downy brome under field or range conditions.

  18. Physiological and biochemical changes in Matricaria chamomilla induced by Pseudomonas fluorescens and water deficit stress

    Directory of Open Access Journals (Sweden)

    Hamid MOHAMMADI

    2018-04-01

    Full Text Available Environmental stresses and rhizosphere microorganisms affect growth parameters and accumulation of active ingredients especially in plants with medicinal properties. The present study examined the effects of chamomile (Matricaria chamomilla L. seedling inoculation with Pseudomonas fluorescens PF-135 strain on its growth parameters, photosynthetic pigments, proline, malondialdehyde (MDA, and hydrogen peroxide (H2O2 content, and essential oil concentration at both regular watering and water deficit experiments. Based on the obtained results, water deficit stress reduced root dry mass, and flower fresh and dry mass as well. However, amount of H2O2 and MDA in root and shoot tissues were considerably lower in inoculated plants compared to non-inoculated ones under both normal watering and water deficit regimes. It indicates that lipid peroxidation and production of reactive oxygen species has been diminished in inoculated plants. Also, essential oil content in inoculated plants significantly increased compared with that of non-inoculated ones under water deficit stress condition. It can be concluded that P. fluorescens PF-135 strain has an outstanding potential to alleviate adverse effects of water deficit on plant growth, and hence can be used as an excellent PGPR in order to boost chamomile productivity especially under water deficit stress condition.

  19. Genome-wide analysis of bacterial determinants of plant growth promotion and induced systemic resistance by Pseudomonas fluorescens

    NARCIS (Netherlands)

    Cheng, Xu; Etalo, Desalegn W.; van de Mortel, Judith E.; Dekkers, Ester; Nguyen, Linh; Medema, Marnix H; Raaijmakers, Jos M.

    2017-01-01

    Pseudomonas fluorescens strain SS101 (Pf.SS101) promotes growth of Arabidopsis thaliana, enhances greening and lateral root formation, and induces systemic resistance (ISR) against the bacterial pathogen Pseudomonas syringae pv. tomato (Pst). Here, targeted and untargeted approaches were adopted to

  20. Kinetic modelling of enzyme inactivation : kinetics of heat inactivation of the extracellular proteinase from Pseudomonas fluorescens 22F

    NARCIS (Netherlands)

    Schokker, E.P.

    1997-01-01

    The kinetics of heat inactivation of the extracellular proteinase from Pseudomonas fluorescens 22F was studied. It was established, by making use of kinetic modelling, that heat inactivation in the temperature range 35 - 70 °C was most likely caused

  1. Gac-mediated changes in pyrroloquinoline quinone biosynthesis enhance the antimicrobial activity of Pseudomonas fluorescens SBW25

    NARCIS (Netherlands)

    Cheng, X.; Voort, van der M.; Raaijmakers, J.M.

    2015-01-01

    In Pseudomonas species, production of secondary metabolites and exoenzymes is regulated by the GacS/GacA two-component regulatory system. In P. fluorescens SBW25, mutations in the Gac-system cause major transcriptional changes and abolished production of the lipopeptide viscosin and of an

  2. Understanding the molecular basis of plant growth promotional effect of Pseudomonas fluorescens on rice through protein profiling

    Directory of Open Access Journals (Sweden)

    Thiruvengadam Raguchander

    2009-12-01

    Full Text Available Abstract Background Plant Growth Promoting Rhizobacteria (PGPR, Pseudomonas fluorescens strain KH-1 was found to exhibit plant growth promotional activity in rice under both in-vitro and in-vivo conditions. But the mechanism underlying such promotional activity of P. fluorescens is not yet understood clearly. In this study, efforts were made to elucidate the molecular responses of rice plants to P. fluorescens treatment through protein profiling. Two-dimensional polyacrylamide gel electrophoresis strategy was adopted to identify the PGPR responsive proteins and the differentially expressed proteins were analyzed by mass spectrometry. Results Priming of P. fluorescens, 23 different proteins found to be differentially expressed in rice leaf sheaths and MS analysis revealed the differential expression of some important proteins namely putative p23 co-chaperone, Thioredoxin h- rice, Ribulose-bisphosphate carboxylase large chain precursor, Nucleotide diPhosphate kinase, Proteosome sub unit protein and putative glutathione S-transferase protein. Conclusion Functional analyses of the differential proteins were reported to be directly or indirectly involved in growth promotion in plants. Thus, this study confirms the primary role of PGPR strain KH-1 in rice plant growth promotion.

  3. Understanding the molecular basis of plant growth promotional effect of Pseudomonas fluorescens on rice through protein profiling.

    Science.gov (United States)

    Kandasamy, Saveetha; Loganathan, Karthiba; Muthuraj, Raveendran; Duraisamy, Saravanakumar; Seetharaman, Suresh; Thiruvengadam, Raguchander; Ponnusamy, Balasubramanian; Ramasamy, Samiyappan

    2009-12-24

    Plant Growth Promoting Rhizobacteria (PGPR), Pseudomonas fluorescens strain KH-1 was found to exhibit plant growth promotional activity in rice under both in-vitro and in-vivo conditions. But the mechanism underlying such promotional activity of P. fluorescens is not yet understood clearly. In this study, efforts were made to elucidate the molecular responses of rice plants to P. fluorescens treatment through protein profiling. Two-dimensional polyacrylamide gel electrophoresis strategy was adopted to identify the PGPR responsive proteins and the differentially expressed proteins were analyzed by mass spectrometry. Priming of P. fluorescens, 23 different proteins found to be differentially expressed in rice leaf sheaths and MS analysis revealed the differential expression of some important proteins namely putative p23 co-chaperone, Thioredoxin h- rice, Ribulose-bisphosphate carboxylase large chain precursor, Nucleotide diPhosphate kinase, Proteosome sub unit protein and putative glutathione S-transferase protein. Functional analyses of the differential proteins were reported to be directly or indirectly involved in growth promotion in plants. Thus, this study confirms the primary role of PGPR strain KH-1 in rice plant growth promotion.

  4. Effects of Pseudomonas fluorescens on the Water Parameters of Mycorrhizal and Non-Mycorrhizal Seedlings of Pinus halepensis

    Directory of Open Access Journals (Sweden)

    José A. Saiz de Omeñaca

    2013-08-01

    Full Text Available Inoculation of forest seedlings with mycorrhizal fungi and rhizobacteria can improve the morphological and physiological qualities of plants, especially those used for regeneration of arid areas. In this paper, under standard nursery conditions, Aleppo pine seedlings were inoculated with Pseudomonas fluorescens CECT 5281 rhizobacteria. Some of these seedlings were also inoculated with the ectomycorrhizal fungus Pisolithus tinctorius. Five months after the inoculations, we examined the growth, water parameters (osmotic potential at full turgor [Ψπfull], osmotic potential at zero turgor [Ψπ0], and the tissue modulus of elasticity near full turgor [Emax], mycorrhizal colonisation, and concentration of macronutrients (N, P, K, Ca and Mg in the seedlings. Subsequently, a trial was conducted to assess the root growth potential. P. fluorescens CECT 5281 decreased the cellular osmotic potential of P. halepensis seedlings but increased its elasticity. P. tinctorius + P. fluorescens caused osmotic adjustment at zero turgor and increased tissue elasticity, which improved tolerance to water stress. All inoculations improved the growth and nutrition of the seedlings but caused non-significant effects on root growth potential. The co-inoculation Pisolithus tinctorius + Pseudomonas fluorescens at the nursery may be a suitable technique for producing improved seedling material for restoration purposes.

  5. Roles of Rhizoxin and 2,4-diacetylphloroglucinol in Suppression of Fusarium spp. by the Rhizobacterium Pseudomonas fluorescens Pf-5

    Science.gov (United States)

    Pseudomonas fluorescens strain Pf-5 is a rhizosphere bacterium that acts as a biocontrol agent of soilborne plant diseases and produces at least 10 different secondary metabolites, including several with antifungal properties. We derived site-directed mutants of Pf-5 with single and multiple mutatio...

  6. Characterization of toxin complex gene clusters and insect toxicity of bacteria representing four subgroups of Pseudomonas fluorescens

    Science.gov (United States)

    Ten strains representing four lineages of Pseudomonas (P. chlororaphis, P. corrugata, P. koreensis, and P. fluorescens subgroups) were evaluated for toxicity to the tobacco hornworm Manduca sexta and the fruit fly Drosophila melanogaster. The three strains within the P. chlororaphis subgroup exhibi...

  7. LETHALITY OF PSEUDOMONAS FLUORESCENS STRAIN CLO145A TO THE 2 ZEBRA MUSSEL SPECIES PRESENT IN NORTH AMERICA

    Energy Technology Data Exchange (ETDEWEB)

    Daniel P. Molloy

    2001-10-28

    These experiments indicated that bacterial strain CL0145A of Pseudomonas fluorescens is equally lethal to the 2 zebra mussel species present in North America, Dreissena polymorpha and Dreissena bugensis. Thus, this bacterial strain should be equally effective at killing zebra mussels in power plant pipes, irrespective of which species is present.

  8. LETHALITY OF PSEUDOMONAS FLUORESCENS STRAIN CLO145A TO THE 2 ZEBRA MUSSEL SPECIES PRESENT IN NORTH AMERICA

    International Nuclear Information System (INIS)

    Molloy, Daniel P.

    2001-01-01

    These experiments indicated that bacterial strain CL0145A of Pseudomonas fluorescens is equally lethal to the 2 zebra mussel species present in North America, Dreissena polymorpha and Dreissena bugensis. Thus, this bacterial strain should be equally effective at killing zebra mussels in power plant pipes, irrespective of which species is present

  9. Detoxification of selenite and mercury by reduction and mutual protection in the assimilation of both elements by Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Belzile, Nelson [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6 (Canada)]. E-mail: nbelzile@laurentian.ca; Wu Gaojun [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6 (Canada); Chen, Yu-Wei [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6 (Canada); Appanna, Vasu D. [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, P3E 2C6 (Canada)

    2006-08-31

    A study on the assimilation and detoxification of selenium and mercury and on the interaction between these two elements was conducted on Pseudomonas fluorescens. P. fluorescens was able to convert separately both elements to their elemental forms, which are less toxic and biologically less available. To study the converting mechanism of selenite to elemental Se, cells were grown in the presence of various selenite concentrations and several parameters such as extracellular protein concentrations, pH, carbohydrate concentrations, isocitrate dehydrogenase (ICDH) and malic enzyme were monitored. Transmission electron microscopy (TEM) and various analytical methods were applied to confirm the interaction between selenium and cell. The former appeared as a red precipitate localized predominantly in the consumed culture medium. P. fluorescens also resisted to the toxic effect of mercury by converting Hg{sup 2+} to the volatile and less toxic form Hg . Mercury reductase was likely responsible for the conversion of Hg{sup 2+} to Hg . More importantly, the interaction between mercury and selenium was also studied. The presence of selenite significantly reduced the accumulation of mercury in P. fluorescens. It was also interesting to note that mercury appeared to behave as a protecting agent against selenium intoxication as the bioaccumulation of Se was also inhibited by this metal. The formation of Se-Hg complexes could explain this mutual protective effect. No precipitate of elemental Se could be detected when Hg was present in the cultures.

  10. Detoxification of selenite and mercury by reduction and mutual protection in the assimilation of both elements by Pseudomonas fluorescens

    International Nuclear Information System (INIS)

    Belzile, Nelson; Wu Gaojun; Chen, Yu-Wei; Appanna, Vasu D.

    2006-01-01

    A study on the assimilation and detoxification of selenium and mercury and on the interaction between these two elements was conducted on Pseudomonas fluorescens. P. fluorescens was able to convert separately both elements to their elemental forms, which are less toxic and biologically less available. To study the converting mechanism of selenite to elemental Se, cells were grown in the presence of various selenite concentrations and several parameters such as extracellular protein concentrations, pH, carbohydrate concentrations, isocitrate dehydrogenase (ICDH) and malic enzyme were monitored. Transmission electron microscopy (TEM) and various analytical methods were applied to confirm the interaction between selenium and cell. The former appeared as a red precipitate localized predominantly in the consumed culture medium. P. fluorescens also resisted to the toxic effect of mercury by converting Hg 2+ to the volatile and less toxic form Hg . Mercury reductase was likely responsible for the conversion of Hg 2+ to Hg . More importantly, the interaction between mercury and selenium was also studied. The presence of selenite significantly reduced the accumulation of mercury in P. fluorescens. It was also interesting to note that mercury appeared to behave as a protecting agent against selenium intoxication as the bioaccumulation of Se was also inhibited by this metal. The formation of Se-Hg complexes could explain this mutual protective effect. No precipitate of elemental Se could be detected when Hg was present in the cultures

  11. Isolation of Biosurfactant–Producing Bacteria with Antimicrobial Activity against Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Siripun Sarin

    2011-01-01

    Full Text Available The aims of this research were to study biosurfactant producing bacteria isolated from soil and to determine their property and efficiency as biosurfactants in order to inhibit bacterial pathogens. The result showed that there were 8 bacterial isolates out of 136 isolates of the total biosurfactant producing bacteria screened that exhibited the diameter of clear zone more than 1.5 cm. in the oil spreading test. The highest potential of emulsifying activity (%EA24 of 54.4 and the maximum additive concentration, (%MAC of 24.2 was obtained from the fermentation broth of the G7 isolate which the G7 isolate was later identified as Pseudomonas fluorescens. Escherichia coli, Staphylococcus aureus and Psuedomonas aeruginosa were the tested bacterial pathogens that were most sensitive to the acid precipitated biosurfactant obtained from P. fluorescens G7 with the lowest minimum inhibitory concentration (MIC of 41.6 mg/ml and minimum bactericidal concentration (MBC of 41.6 mg/ml compared with the acid precipitated bisurfactants of the other isolates used in the antimicrobial activity test. The type of the separated crude biosurfactant produced by P. fluorescens G7 analyzed later by using the rhamose test, TLC and FT-IR techniques was rhamnolipid.

  12. Influencia de la concentración salina y la temperatura en la composición de ácidos grasos de membrana de Pseudomonas fluorescens GNP-OHP-3 Influence of salinity and temperature on fatty acid composition of Pseudomonas fluorescens GNP-OHP-3 membrane

    Directory of Open Access Journals (Sweden)

    G. N. Pucci

    2004-03-01

    Full Text Available Las bacterias responden a los cambios ambientales modificando su composición, para evitar el daño que dichos cambios podrían ejercer. Una de las modificaciones más importantes es la variación de la composición de los ácidos grasos de las membranas celulares, que le permite mantener la homeoviscosidad ante situaciones de estrés. Trabajos previos han estudiado la acción de la temperatura, presión hidrostática y diferentes solventes sobre cepas de Pseudomonas putida. En este trabajo se estudió la acción conjunta de la temperatura y la salinidad sobre la composición de ácidos grasos de membranas celulares de Pseudomonas fluorescens GNP-OHP-3, una cepa bacteriana aislada de un hábitat contaminado con petróleo. Pseudomonas fluorescens GNP-OHP-3 respondió a las variaciones de temperatura modificando los ácidos grasos de sus membranas de manera similar a lo descripto en otros integrantes de su género: ante el aumento de temperatura se observó un incremento de ácidos grasos saturados y una disminución de los ácidos grasos insaturados. En el rango de concentraciones salinas ensayadas las variaciones de los ácidos grasos mayoritarios fueron en general erráticas. La respuesta de los ácidos grasos ciclo propano pudo expresarse con ecuaciones matemáticas que permitieron predecir el porcentaje de estos ácidos en relación a la concentración de cloruro de sodio.The bacteria respond to environmental changes modifying their composition. One of the most important modifications is the variation on fatty acid composition of cellular membranes to maintain the homeoviscosity. The action of temperature, hydrostatic pressure and solvents on Pseudomonas putida has been thoroughly studied. In this paper, the combined action of the temperature and salinity on fatty acid composition of cellular membranes of Pseudomonas fluorescens GNP-OHP-3, a bacterial strain isolated from a petroleum contaminated habitat, was studied. The modifications in the

  13. INFLUÊNCIA DA ATIVIDADE ENZIMÁTICA DE PSEUDOMONAS FLUORESCENS 041 EM LABNEH

    Directory of Open Access Journals (Sweden)

    Andreza Angélica Ferreira

    2012-04-01

    Full Text Available A refrigeração do leite proporciona a seleção de bactérias psicrotróficas deteriorantes produtoras de enzimas termoresistentes que podem comprometer a qualidade do leite e derivados. O objetivo deste trabalho foi avaliar as implicações causadas pela atividade enzimática de Pseudomonas fluorescens 041 na produção de Labneh. O leite pasteurizado foi inoculado intencionalmente com, aproximadamente, 106 UFC.mL-1 de P. fluorescens 041 e Labneh foi produzido imediatamente após inoculação no leite (tempo 0 e após 48, 72 e 96 horas de inoculação e armazenamento a 4 ºC. A qualidade físico-química do leite, do Labneh e do soro resultante da fabricação foi determinada. O rendimento prático, o rendimento técnico ajustado e o aproveitamento final de sólidos no Labneh em relação ao volume de leite (coeficiente GL também foram avaliados. Constatou-se alterações nas características físico-químicas do soro e do Labneh fabricado com leite armazenado a partir de 48 horas. Também, observou-se um aumento significativo em litros de leite destinado à produção de um quilo do produto ao longo do tempo de estocagem do leite inoculado com P. fluorescens 041, sendo os rendimentos prático, técnico ajustado e o coeficiente GL afetados pelo fator tempo. Portanto, a redução do tempo de estocagem do leite sob refrigeração e a prevenção da contaminação da matéria-prima por meio da adoção de boas práticas na cadeia do leite são medidas a serem adotadas para assegurar a qualidade e o rendimento do produto final.

  14. Biocidal Activity of Formaldehyde and Nonformaldehyde Biocides toward Mycobacterium immunogenum and Pseudomonas fluorescens in Pure and Mixed Suspensions in Synthetic Metalworking Fluid and Saline

    OpenAIRE

    Selvaraju, Suresh B.; Khan, Izhar U. H.; Yadav, Jagjit S.

    2005-01-01

    The microbicidal activity of four different biocides was studied in synthetic metalworking fluid (MWF) against Mycobacterium immunogenum, a suspected causative agent for hypersensitivity pneumonitis, and Pseudomonas fluorescens, a representative for the predominant gram-negative bacterial contaminants of MWF. The results indicated that M. immunogenum is more resistant than P. fluorescens to the tested formaldehyde-releasing biocides (Grotan and Bioban), isothiazolone (Kathon), and phenolic bi...

  15. Exploiting genotypic diversity of 2,4-diacetylphloroglucinol-producing Pseudomonas spp.: characterization of superior root-colonizing P. fluorescens strain Q8r1-96.

    Science.gov (United States)

    Raaijmakers, J M; Weller, D M

    2001-06-01

    The genotypic diversity that occurs in natural populations of antagonistic microorganisms provides an enormous resource for improving biological control of plant diseases. In this study, we determined the diversity of indigenous 2,4-diacetylphloroglucinol (DAPG)-producing Pseudomonas spp. occurring on roots of wheat grown in a soil naturally suppressive to take-all disease of wheat. Among 101 isolates, 16 different groups were identified by random amplified polymorphic DNA (RAPD) analysis. One RAPD group made up 50% of the total population of DAPG-producing Pseudomonas spp. Both short- and long-term studies indicated that this dominant genotype, exemplified by P. fluorescens Q8r1-96, is highly adapted to the wheat rhizosphere. Q8r1-96 requires a much lower dose (only 10 to 100 CFU seed(-1) or soil(-1)) to establish high rhizosphere population densities (10(7) CFU g of root(-1)) than Q2-87 and 1M1-96, two genotypically different, DAPG-producing P. fluorescens strains. Q8r1-96 maintained a rhizosphere population density of approximately 10(5) CFU g of root(-1) after eight successive growth cycles of wheat in three different, raw virgin soils, whereas populations of Q2-87 and 1M1-96 dropped relatively quickly after five cycles and were not detectable after seven cycles. In short-term studies, strains Q8r1-96, Q2-87, and 1M1-96 did not differ in their ability to suppress take-all. After eight successive growth cycles, however, Q8r1-96 still provided control of take-all to the same level as obtained in the take-all suppressive soil, whereas Q2-87 and 1M1-96 gave no control anymore. Biochemical analyses indicated that the superior rhizosphere competence of Q8r1-96 is not related to in situ DAPG production levels. We postulate that certain rhizobacterial genotypes have evolved a preference for colonization of specific crops. By exploiting diversity of antagonistic rhizobacteria that share a common trait, biological control can be improved significantly.

  16. Pseudomonas fluorescens JH 70-4 promotes pb stabilization and early seedling growth of sudan grass in contaminated mining site soil.

    Science.gov (United States)

    Shim, Jaehong; Babu, A Giridhar; Velmurugan, Palanivel; Shea, Patrick J; Oh, Byung-Taek

    2014-01-01

    A bacterial strain (JH 70-4) exhibiting plant growth promoting characteristics (indoleacetic acid production and 1-aminocyclopropane-1-carboxylate deaminase activity), as well as heavy metal(loid) (HM) tolerance and Pb precipitation, was isolated from HM-contaminated soil at an abandoned mine site. The bacterium was identified as Pseudomonas fluorescens based on 16S rDNA sequencing. The JH 70-4 strain induced precipitation of Pb as PbS nanoparticles, confirmed by X-ray diffraction. Solution pH, incubation time, and Pb concentration influenced removal and PbS formation. Inoculating contaminated soil with JH 70-4 decreased Pb availability; exchangeable Pb decreased while organic- and sulphide-bound Pb increased. The toxicity characteristic leaching procedure showed a 65% decrease in Pb in leachate 60 d after inoculating soil with JH 70-4. Shoot and root lengths of Sudan grass grown in the inoculated soil were greater than in the uninoculated soil. Findings suggest that microbial Pb fixation is a viable strategy for remediating soil and promoting plant growth for phytostabilization of contaminated sites.

  17. Enlightening mineral iron sensing in Pseudomonas fluorescens by surface active maghemite nanoparticles: Involvement of the OprF porin.

    Science.gov (United States)

    Magro, Massimiliano; Fasolato, Luca; Bonaiuto, Emanuela; Andreani, Nadia Andrea; Baratella, Davide; Corraducci, Vittorino; Miotto, Giovanni; Cardazzo, Barbara; Vianello, Fabio

    2016-10-01

    Mineral iron(III) recognition by bacteria is considered a matter of debate. The peculiar surface chemistry of novel naked magnetic nanoparticles, called SAMNs (surface active maghemite nanoparticles) characterized by solvent exposed Fe(3+) sites on their surface, was exploited for studying mineral iron sensing in Pseudomonas fluorescens. SAMNs were applied for mimicking Fe(3+) ions in solution, acting as magnetically drivable probes to evaluate putative Fe(3+) recognition sites on the microorganism surface. Culture broths and nano-bio-conjugates were characterized by UV-Vis spectroscopy and mass spectrometry. The whole heritage of a membrane porin (OprF) of P. fluorescens Ps_22 cells was recognized and firmly bound by SAMNs. The binding of nanoparticles to OprF porin was correlated to a drastic inhibition of a siderophore (pyoverdine) biosynthesis and to the stimulation of the production and rate of formation of a secondary siderophore. The analysis of metabolic pathways, based on P. fluorescens Ps_22 genomic information, evidenced that this putative secondary siderophore does not belong to a selection of the most common siderophores. In the scenario of an adhesion mechanism, it is plausible to consider OprF as the biological component deputed to the mineral iron sensing in P. fluorescens Ps_22, as well as one key of siderophore regulation. The present work sheds light on mineral iron sensing in microorganisms. Peculiar colloidal naked iron oxide nanoparticles offer a useful approach for probing the adhesion of bacterial surface on mineral iron for the identification of the specific recognition site for this iron uptake regulation in microorganisms. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Efficacy of Pseudomonas fluorescens (Pf-CL145A) spray dried powder for controlling zebra mussels adhering to test substrates

    Science.gov (United States)

    Luoma, James A.; Severson, Todd J.; Weber, Kerry L.; Mayer, Denise A.

    2015-01-01

    A mobile bioassay trailer was used to assess the efficacy of Pseudomonas fluorescens (Pf-CL145A) spray dried powder (SDP) formulation for controlling zebra mussels (Dreissena polymorpha) from two midwestern lakes: Lake Carlos (Alexandria, Minnesota) and Shawano Lake (Shawano, Wisconsin). The effects of SDP exposure concentration and exposure duration on zebra mussel survival were evaluated along with the evaluation of a benthic injection application technique to reduce the amount of SDP required to induce zebra mortality.

  19. Small RNA-dependent expression of secondary metabolism is controlled by Krebs cycle function in Pseudomonas fluorescens.

    Science.gov (United States)

    Takeuchi, Kasumi; Kiefer, Patrick; Reimmann, Cornelia; Keel, Christoph; Dubuis, Christophe; Rolli, Joëlle; Vorholt, Julia A; Haas, Dieter

    2009-12-11

    Pseudomonas fluorescens CHA0, an antagonist of phytopathogenic fungi in the rhizosphere of crop plants, elaborates and excretes several secondary metabolites with antibiotic properties. Their synthesis depends on three small RNAs (RsmX, RsmY, and RsmZ), whose expression is positively controlled by the GacS-GacA two-component system at high cell population densities. To find regulatory links between primary and secondary metabolism in P. fluorescens and in the related species Pseudomonas aeruginosa, we searched for null mutations that affected central carbon metabolism as well as the expression of rsmY-gfp and rsmZ-gfp reporter constructs but without slowing down the growth rate in rich media. Mutation in the pycAB genes (for pyruvate carboxylase) led to down-regulation of rsmXYZ and secondary metabolism, whereas mutation in fumA (for a fumarase isoenzyme) resulted in up-regulation of the three small RNAs and secondary metabolism in the absence of detectable nutrient limitation. These effects required the GacS sensor kinase but not the accessory sensors RetS and LadS. An analysis of intracellular metabolites in P. fluorescens revealed a strong positive correlation between small RNA expression and the pools of 2-oxoglutarate, succinate, and fumarate. We conclude that Krebs cycle intermediates (already known to control GacA-dependent virulence factors in P. aeruginosa) exert a critical trigger function in secondary metabolism via the expression of GacA-dependent small RNAs.

  20. Impact du séchage sur la viabilité de Pseudomonas fluorescens (synthèse bibliographique

    Directory of Open Access Journals (Sweden)

    Mputu Kanyinda, JN.

    2014-01-01

    Full Text Available Impact of drying on Pseudomonas fluorescens viability. A review. Drying Pseudomonas fluorescens makes for more economical storage, transportation and marketing. The aim of the drying process is to stop and to stabilize all biological activity for optimal storage, compatible with the conservation of the maximum desired viability of the microorganisms. However, the viability rate of the bacteria after drying depends on the operating conditions of the drying process. One of the most important criteria to consider during the drying of biologically active products is the quality of the final dried product. Freeze-drying is the drying method most commonly used for Pseudomonas fluorescens. After their production, the bacteria are harvested by centrifugation and are freeze-dried, but the changes in temperature induced by freeze-drying are not without consequence for the cells. The freeze-drying process induces cell damage: peroxidation of fatty acids and proteins and DNA oxidation. However, use of protective compounds during freeze-drying and during storage increases significantly the rate of cell viability.

  1. Pseudomonas fluorescens induces strain-dependent and strain-independent host plant responses in defense networks, primary metabolism and photosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Pelletier, Dale A [ORNL; Morrell-Falvey, Jennifer L [ORNL; Karve, Abhijit A [ORNL; Lu, Tse-Yuan S [ORNL; Tschaplinski, Timothy J [ORNL; Tuskan, Gerald A [ORNL; Chen, Jay [ORNL; Martin, Madhavi Z [ORNL; Jawdy, Sara [ORNL; Weston, David [ORNL; Doktycz, Mitchel John [ORNL; Schadt, Christopher Warren [ORNL

    2012-01-01

    Colonization of plants by nonpathogenic Pseudomonas fluorescens strains can confer enhanced defense capacity against a broad spectrum of pathogens. Few studies, however, have linked defense pathway regulation to primary metabolism and physiology. In this study, physiological data, metabolites, and transcript profiles are integrated to elucidate how molecular networks initiated at the root-microbe interface influence shoot metabolism and whole-plant performance. Experiments with Arabidopsis thaliana were performed using the newly identified P. fluorescens GM30 or P. fluorescens Pf-5 strains. Co-expression networks indicated that Pf-5 and GM30 induced a subnetwork specific to roots enriched for genes participating in RNA regulation, protein degradation, and hormonal metabolism. In contrast, only GM30 induced a subnetwork enriched for calcium signaling, sugar and nutrient signaling, and auxin metabolism, suggesting strain dependence in network architecture. In addition, one subnetwork present in shoots was enriched for genes in secondary metabolism, photosynthetic light reactions, and hormone metabolism. Metabolite analysis indicated that this network initiated changes in carbohydrate and amino acid metabolism. Consistent with this, we observed strain-specific responses in tryptophan and phenylalanine abundance. Both strains reduced host plant carbon gain and fitness, yet provided a clear fitness benefit when plants were challenged with the pathogen P. syringae DC3000.

  2. A type VI secretion system is involved in Pseudomonas fluorescens bacterial competition.

    Directory of Open Access Journals (Sweden)

    Victorien Decoin

    Full Text Available Protein secretion systems are crucial mediators of bacterial interactions with other organisms. Among them, the type VI secretion system (T6SS is widespread in Gram-negative bacteria and appears to inject toxins into competitor bacteria and/or eukaryotic cells. Major human pathogens, such as Vibrio cholerae, Burkholderia and Pseudomonas aeruginosa, express T6SSs. Bacteria prevent self-intoxication by their own T6SS toxins by producing immunity proteins, which interact with the cognate toxins. We describe here an environmental P. fluorescens strain, MFE01, displaying an uncommon oversecretion of Hcp (hemolysin-coregulated protein and VgrG (valine-glycine repeat protein G into the culture medium. These proteins are characteristic components of a functional T6SS. The aim of this study was to attribute a role to this energy-consuming overexpression of the T6SS. The genome of MFE01 contains at least two hcp genes (hcp1 and hcp2, suggesting that there may be two putative T6SS clusters. Phenotypic studies have shown that MFE01 is avirulent against various eukaryotic cell models (amebas, plant or animal cell models, but has antibacterial activity against a wide range of competitor bacteria, including rhizobacteria and clinical bacteria. Depending on the prey cell, mutagenesis of the hcp2 gene in MFE01 abolishes or reduces this antibacterial killing activity. Moreover, the introduction of T6SS immunity proteins from S. marcescens, which is not killed by MFE01, protects E. coli against MFE01 killing. These findings suggest that the protein encoded by hcp2 is involved in the killing activity of MFE01 mediated by effectors of the T6SS targeting the peptidoglycan of Gram-negative bacteria. Our results indicate that MFE01 can protect potato tubers against Pectobacterium atrosepticum, which causes tuber soft rot. Pseudomonas fluorescens is often described as a major PGPR (plant growth-promoting rhizobacterium, and our results suggest that there may be a

  3. Genetic characterization of psp encoding the DING protein in Pseudomonas fluorescens SBW25

    Directory of Open Access Journals (Sweden)

    Zhang Xue-Xian

    2007-12-01

    Full Text Available Abstract Background DING proteins constitute a conserved and broadly distributed set of proteins found in bacteria, fungi, plants and animals (including humans. Characterization of DING proteins from animal and plant tissues indicated ligand-binding ability suggesting a role for DING proteins in cell signaling and biomineralization. Surprisingly, the genes encoding DING proteins in eukaryotes have not been identified in the eukaryotic genome or EST databases. Recent discovery of a DING homologue (named Psp here in the genome of Pseudomonas fluorescens SBW25 provided a unique opportunity to investigate the physiological roles of DING proteins. P. fluorescens SBW25 is a model bacterium that can efficiently colonize plant surfaces and enhance plant health. In this report we genetically characterize Psp with a focus on conditions under which psp is expressed and the protein exported. Results Psp is closely related to the periplasmic Pi binding component of the ABC-type phosphate transporter system (Pst. psp is flanked by a gene cluster predicted to function as a type II protein secretion system (Hxc. Deletion analysis combined with chromosomally integrated 'lacZ fusions showed that both psp and pstC are induced by Pi limitation and that pstC is required for competitive growth of the bacterium in Pi limited medium. hxcR is not regulated by Pi limitation. Psp was detected (using anti-DING serum in the supernatant of wild-type culture but was greatly reduced in the supernatant of an isogenic strain carrying an hxcR mutation (ΔhxcR. A promoter fusion between hxcR and a promoterless copy of a gene ('dapB essential for growth in the plant environment showed that expression of hxcR is elevated during colonization of sugar beet seedlings. A similar analysis of psp showed that it is not induced in the plant environment. Conclusion Psp gene is expressed under conditions of Pi limitation. It is an exoprotein secreted mainly via the Hxc type II secretion

  4. Genetic characterization of psp encoding the DING protein in Pseudomonas fluorescens SBW25.

    Science.gov (United States)

    Zhang, Xue-Xian; Scott, Ken; Meffin, Rebecca; Rainey, Paul B

    2007-12-18

    DING proteins constitute a conserved and broadly distributed set of proteins found in bacteria, fungi, plants and animals (including humans). Characterization of DING proteins from animal and plant tissues indicated ligand-binding ability suggesting a role for DING proteins in cell signaling and biomineralization. Surprisingly, the genes encoding DING proteins in eukaryotes have not been identified in the eukaryotic genome or EST databases. Recent discovery of a DING homologue (named Psp here) in the genome of Pseudomonas fluorescens SBW25 provided a unique opportunity to investigate the physiological roles of DING proteins. P. fluorescens SBW25 is a model bacterium that can efficiently colonize plant surfaces and enhance plant health. In this report we genetically characterize Psp with a focus on conditions under which psp is expressed and the protein exported. Psp is closely related to the periplasmic Pi binding component of the ABC-type phosphate transporter system (Pst). psp is flanked by a gene cluster predicted to function as a type II protein secretion system (Hxc). Deletion analysis combined with chromosomally integrated 'lacZ fusions showed that both psp and pstC are induced by Pi limitation and that pstC is required for competitive growth of the bacterium in Pi limited medium. hxcR is not regulated by Pi limitation. Psp was detected (using anti-DING serum) in the supernatant of wild-type culture but was greatly reduced in the supernatant of an isogenic strain carrying an hxcR mutation (DeltahxcR). A promoter fusion between hxcR and a promoterless copy of a gene ('dapB) essential for growth in the plant environment showed that expression of hxcR is elevated during colonization of sugar beet seedlings. A similar analysis of psp showed that it is not induced in the plant environment. Psp gene is expressed under conditions of Pi limitation. It is an exoprotein secreted mainly via the Hxc type II secretion system, whose expression is elevated on plant surfaces

  5. Effect of Eu(III) on the degradation of malic acid by Pseudomonas fluorescens

    International Nuclear Information System (INIS)

    Nankawa, T.; Ozaki, T.; Ohnuki, T.; Suzuki, Y.; Francis, A.J.

    2005-01-01

    Full text of publication follows: The transuranic elements, such as Am(III) and Cm(III), are highly toxic because they emit high-energy α particles and have long half-lives. To estimate their long-term environmental behavior, we need to elucidate degradation of actinide-organic complexes by microorganisms. We studied the biodegradation of Eu(III)-malic acid complexes by Pseudomonas fluorescens. Malic acid is ubiquitous in the environment and is one of the microbial metabolites that is part of the tri-carboxylic acid (TCA) cycle. Europium(III) is a good analogue for Am(III) and Cm(III). To investigate the effect of Eu(III) on the degradation of malic acid by P. fluorescens, we compared the degradation behavior of Eu(III)-malic acid complexes to that of Fe(III) and Al(III)-malic acid complexes. In the medium containing 1 mM malic acid and 0-0.5 mM Fe(III), malic acid was degraded completely. In the medium containing 1 mM malic acid and 0.05-0.5 mM Al(III), malic acid was degraded until the concentration of malic acid became equal to that of Al(III), indicating that Al(III)-malic acid complex with 1: 1 molar ratio was recalcitrant to biodegradation. In the medium containing 1 mM malic acid and 0.05-0.5 mM Eu(III), degradation of malic acid was not observed. The effect of metals on degradation of malic acid was in the order of Fe(III) < Al(III) < Eu(III). The stability constants of 1:1 Fe(III)-, Al(III)-, and Eu(III)-malic acid complexes are 7.1, 4.6, and 4.9, respectively. These results indicate that degradability of malic acid does not depend on the stability constants of metal-malic acid complexes. We found that 10 mM malic acid was degraded in the presence of 0.05 and 0.1 mM Eu(III) but 1 mM malic acid was not degraded in the presence of 0.05 and 0.1 mM Eu(III). The degradation rate of malic acid increased with a decreasing ratio of Eu(III) to malic acid. (authors)

  6. Metabolic engineering of Pseudomonas fluorescens for the production of vanillin from ferulic acid.

    Science.gov (United States)

    Di Gioia, Diana; Luziatelli, Francesca; Negroni, Andrea; Ficca, Anna Grazia; Fava, Fabio; Ruzzi, Maurizio

    2011-12-20

    Vanillin is one of the most important flavors in the food industry and there is great interest in its production through biotechnological processes starting from natural substrates such as ferulic acid. Among bacteria, recombinant Escherichia coli strains are the most efficient vanillin producers, whereas Pseudomonas spp. strains, although possessing a broader metabolic versatility, rapidly metabolize various phenolic compounds including vanillin. In order to develop a robust Pseudomonas strain that can produce vanillin in high yields and at high productivity, the vanillin dehydrogenase (vdh)-encoding gene of Pseudomonas fluorescens BF13 strain was inactivated via targeted mutagenesis. The results demonstrated that engineered derivatives of strain BF13 accumulate vanillin if inactivation of vdh is associated with concurrent expression of structural genes for feruloyl-CoA synthetase (fcs) and hydratase/aldolase (ech) from a low-copy plasmid. The conversion of ferulic acid to vanillin was enhanced by optimization of growth conditions, growth phase and parameters of the bioconversion process. The developed strain produced up to 8.41 mM vanillin, which is the highest final titer of vanillin produced by a Pseudomonas strain to date and opens new perspectives in the use of bacterial biocatalysts for biotechnological production of vanillin from agro-industrial wastes which contain ferulic acid. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Effects of high intensity pulsed electric field and thermal treatments on a lipase from Pseudomonas fluorescens.

    Science.gov (United States)

    Bendicho, S; Estela, C; Giner, J; Barbosa-Cánovas, G V; Martin, O

    2002-01-01

    Milk and dairy products may contain microorganisms capable of secreting lipases that cause sensory defects and technological problems in the dairy industry. In this study, the effects of thermal and high-intensity pulsed electric field (HIPEF) treatments on an extracellular lipase from Pseudomonas fluorescens, suspended in a simulated skim milk ultrafiltrate (SMUF) have been evaluated. Heat treatments applied were up to 30 min from 50 to 90 degrees C. HIPEF treatments were carried out using pilot plant facilities in a batch or continuous flow mode, where treatment chambers consisted of parallel and coaxial configuration, respectively. Samples were subjected to up to 80 pulses at electric field intensities ranging from 16.4 to 37.3 kV/cm. This resulted in a lipase that was quite resistant to heat and also to HIPEF. High (75 degrees C-15 s) and low pasteurization treatments (63 degrees C-30 min) led to inactivations of 5 and 20%, respectively. Using the batch-mode HIPEF equipment, a 62.1% maximum activity depletion was achieved after 80 pulses at 27.4 kV/cm. However, when HIPEF treatments were applied in the continuous flow mode, an inactivation rate of just 13% was achieved, after applying 80 pulses at 37.3 kV/cm and 3.5 Hz. The results of both heat and HIPEF treatments on enzyme inactivation were adjusted with good agreement to a first-order kinetic model (R2 > 62.3%).

  8. Modeling high-intensity pulsed electric field inactivation of a lipase from Pseudomonas fluorescens.

    Science.gov (United States)

    Soliva-Fortuny, R; Bendicho-Porta, S; Martín-Belloso, O

    2006-11-01

    The inactivation kinetics of a lipase from Pseudomonas fluorescens (EC 3.1.1.3.) were studied in a simulated skim milk ultrafiltrate treated with high-intensity pulsed electric fields. Samples were subjected to electric field intensities ranging from 16.4 to 27.4 kV/cm for up to 314.5 micros, thus achieving a maximum inactivation of 62.1%. The suitability of describing experimental data using mechanistic first-order kinetics and an empirical model based on the Weibull distribution function is discussed. In addition, different mathematical expressions relating the residual activity values to field strength and treatment time are supplied. A first-order fractional conversion model predicted residual activity with good accuracy (A(f) = 1.018). A mechanistic insight of the model kinetics was that experimental values were the consequence of different structural organizations of the enzyme, with uneven resistance to the pulsed electric field treatments. The Weibull model was also useful in predicting the energy density necessary to achieve lipase inactivation.

  9. Pit formation on stainless steel surfaces pre-treated with biosurfactants produced by Pseudomonas fluorescens

    International Nuclear Information System (INIS)

    Dagbert, Catherine; Meylheuc, Thierry; Bellon-Fontaine, Marie-Noelle

    2008-01-01

    Today, it is widely established that the surface tension of water can be reduced by some microorganisms capable of synthesizing surface-active compounds called biosurfactants (BS). BS characteristics depend on the microorganism that produces them and therefore, on the microorganism culture conditions. Some studies on chemical surfactants have shown that the adsorption of surface-active compounds plays a major role in corrosion; indeed they are used as a good corrosion inhibition tool. The purpose of this study was first, to estimate the importance and behavior of the stainless steels passive film on the adsorption of BS, produced by the Gram negative bacteria Pseudomonas fluorescens, and secondly, to study the impact of these treatments on the pitting corrosion. In this paper, the galvanostatic polarization technique, used as accelerated method for determining the characteristic pit potentials on stainless steels, is examined. Pit growth, shape and cover formation were also observed. The surface topography of the corroded specimens was investigated using field emission scanning electron microscopy (FESEM)

  10. Pit formation on stainless steel surfaces pre-treated with biosurfactants produced by Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Dagbert, Catherine [ECP-LGPM, Grande Voie des Vignes, 92295 Chatenay-Malabry (France)], E-mail: catherine.dagbert@ecp.fr; Meylheuc, Thierry; Bellon-Fontaine, Marie-Noelle [INRA, UMR 763 Bioadhesion et Hygiene des Materiaux, F-91300 Massy (France); AGROPARISTECH, UMR 763 Bioadhesion et Hygiene des Materiaux, F-91300 Massy (France)

    2008-12-01

    Today, it is widely established that the surface tension of water can be reduced by some microorganisms capable of synthesizing surface-active compounds called biosurfactants (BS). BS characteristics depend on the microorganism that produces them and therefore, on the microorganism culture conditions. Some studies on chemical surfactants have shown that the adsorption of surface-active compounds plays a major role in corrosion; indeed they are used as a good corrosion inhibition tool. The purpose of this study was first, to estimate the importance and behavior of the stainless steels passive film on the adsorption of BS, produced by the Gram negative bacteria Pseudomonas fluorescens, and secondly, to study the impact of these treatments on the pitting corrosion. In this paper, the galvanostatic polarization technique, used as accelerated method for determining the characteristic pit potentials on stainless steels, is examined. Pit growth, shape and cover formation were also observed. The surface topography of the corroded specimens was investigated using field emission scanning electron microscopy (FESEM)

  11. Expression, Purification, Crystallization and Preliminary X-ray Analysis of Pseudomonas fluorescens AlgK

    Energy Technology Data Exchange (ETDEWEB)

    Keiski,C.; Yip, P.; Robinson, H.; Burrows, L.; Howell, P.

    2007-01-01

    AlgK is an outer-membrane lipoprotein involved in the biosynthesis of alginate in Pseudomonads and Azotobacter vinelandii. A recombinant form of Pseudomonas fluorescens AlgK with a C-terminal polyhistidine affinity tag has been expressed and purified from the periplasm of Escherichia coli cells and diffraction-quality crystals of AlgK have been grown using the hanging-drop vapour-diffusion method. The crystals grow as flat plates with unit-cell parameters a = 79.09, b = 107.85, c = 119.15 {angstrom}, = 96.97{sup o}. The crystals exhibit the symmetry of space group P2{sub 1} and diffract to a minimum d-spacing of 2.5 {angstrom} at Station X29 of the National Synchrotron Light Source, Brookhaven National Laboratory. On the basis of the Matthews coefficient (V{sub M} = 2.53 {angstrom}{sup 3} Da{sup -1}), four protein molecules are estimated to be present in the asymmetric unit.

  12. Isolation and identification of plant growth promoting rhizobacteria from maize (Zea mays L.) rhizosphere and their plant growth promoting effect on rice (Oryza sativa L.)

    OpenAIRE

    Karnwal Arun

    2017-01-01

    The use of plant growth promoting rhizobacteria is increasing in agriculture and gives an appealing manner to replace chemical fertilizers, pesticides, and dietary supplements. The objective of our research was to access the plant growth promotion traits of Pseudomonas aeruginosa, P. fluorescens and Bacillus subtilis isolated from the maize (Zea mays L.) rhizosphere. In vitro studies showed that isolates have the potential to produce indole acetic acid (IAA), hydrogen cyanide, phosphate solub...

  13. Influence of phenolic acids on indole acetic acid production and on the type III secretion system gene transcription in food-associated Pseudomonas fluorescens KM05.

    Science.gov (United States)

    Myszka, Kamila; Schmidt, Marcin T; Olejnik-Schmidt, Agnieszka K; Leja, Katarzyna; Czaczyk, Katarzyna

    2014-12-01

    The purpose of these investigations was to evaluate the reduction capability of phenolic acids (ferulic, chlorogenic, gallic, and p-coumaric acids) on indole acetic acid synthesis by food-associated Pseudomonas fluorescens KM05. Specific genetic primer for the type III secretion system (TTSS) in P. fluorescens KM05 was designed and the influence of phenolic acids on its expression was investigated. In the work the ferulic and chlorogenic acids at the concentration of 0.02 and 0.04 μg/ml affected on bacterial growth pattern and the signal molecules production. The phenolic acids, that were appreciable effective against P. fluorescens KM05 indole acetic acid production, significantly suppressed TTSS gene. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  14. Non-target trials with Pseudomonas fluorescens strain CL145A, a lethal control agent of dreissenid mussels (Bivalvia: Dreissenidae

    Directory of Open Access Journals (Sweden)

    Daniel P. Molloy

    2013-01-01

    Full Text Available In an effort to develop an efficacious and environmentally safe method for managing zebra mussels (Dreissena polymorpha and quaggamussels (Dreissena rostriformis bugensis, we initiated a research project investigating the potential use of bacteria and their naturalmetabolic products as biocontrol agents. This project resulted in the discovery of an environmental isolate lethal to dreissenid mussels,Pseudomonas fluorescens strain CL145A (Pf-CL145A. In previous published reports we have demonstrated that: 1 Pf-CL145A’s mode ofaction is intoxication (not infection; 2 natural product within ingested bacterial cells lyse digestive tract epithelial cells leading to dreisseniddeath; and 3 high dreissenid kill rates (>90% are achievable following treatment with Pf-CL145A cells, irrespective of whether thebacterial cells are dead or alive. Investigating the environmental safety of Pf-CL145A was also a key element in our research efforts, andherein, we report the results of non-target trials demonstrating Pf-CL145A’s high specificity to dreissenids. These acute toxicity trials weretypically single-dose, short-term (24-72 h exposures to Pf-CL145A cells under aerated conditions at concentrations highly lethal todreissenids (100 or 200 mg/L. These trials produced no evidence of mortality among the ciliate Colpidium colpoda, the cladoceran Daphniamagna, three fish species (Pimephales promelas, Salmo trutta, and Lepomis macrochirus, and seven bivalve species (Mytilus edulis,Pyganodon grandis, Pyganodon cataracta, Lasmigona compressa, Strophitus undulatus, Lampsilis radiata, and Elliptio complanata. Lowmortality (3-27% was recorded in the amphipod Hyalella azteca, but additional trials suggested that most, if not all, of the mortality couldbe attributed to some other unidentified factor (e.g., possibly particle load or a water quality issue rather than Pf-CL145A’s dreissenidkillingnatural product. In terms of potential environmental safety, the results of

  15. Susceptibility of Mycobacterium immunogenum and Pseudomonas fluorescens to formaldehyde and non-formaldehyde biocides in semi-synthetic metalworking fluids.

    Science.gov (United States)

    Selvaraju, Suresh B; Khan, Izhar U H; Yadav, Jagjit S

    2011-01-20

    Mycobacterium immunogenum, a newly identified member of the Mycobacterium chelonae_M. abscessus complex is considered a potential etiological agent for hypersensitivity pneumonitis (HP) in machine workers exposed to contaminated metalworking fluid (MWF). This study investigated the biocidal efficacy of the frequently applied commercial formaldehyde-releasing (HCHO) biocides Grotan and Bioban CS 1135 and non-HCHO type biocides Kathon 886 MW (isothiazolone) and Preventol CMK 40 (phenolic) toward this emerging mycobacterial species (M. immunogenum) in HP-linked MWFs, alone and in presence of a representative of the Gram-negative bacterial contaminants, Pseudomonas fluorescens, using two semi-synthetic MWF matrices (designated Fluid A and Fluid B). Relative biocide susceptibility analysis indicated M immunogenum to be comparatively more resistant (2-1600 fold) than P. fluorescens to the tested biocides under the varied test conditions. In terms of minimum inhibitory concentration, Kathon was the most effective biocide against M. immunogenum. Fluid factors had a major effect on the biocide susceptibility. Fluid A formulation provided greater protective advantage to the test organisms than Fluid B. Fluid dialysis (Fluid A) led to an increased biocidal efficacy of Grotan, Kathon and Preventol against M. immunogenum further implying the role of native fluid components. Used fluid matrix, in general, increased the resistance of the two test organisms against the biocides, with certain exceptions. M. immunogenum resistance increased in presence of the co-contaminant P. fluorescens. Collectively, the results show a multifactorial nature of the biocide susceptibility of MWF-colonizing mycobacteria and highlight the importance of more rigorous efficacy testing and validation of biocides prior to and during their application in metalworking fluid operations.

  16. Susceptibility of Mycobacterium immunogenum and Pseudomonas fluorescens to Formaldehyde and Non-Formaldehyde Biocides in Semi-Synthetic Metalworking Fluids

    Directory of Open Access Journals (Sweden)

    Suresh B. Selvaraju

    2011-01-01

    Full Text Available Mycobacterium immunogenum, a newly identified member of the Mycobacterium chelonae_M. abscessus complex is considered a potential etiological agent for hypersensitivity pneumonitis (HP in machine workers exposed to contaminated metalworking fluid (MWF. This study investigated the biocidal efficacy of the frequently applied commercial formaldehyde-releasing (HCHO biocides Grotan and Bioban CS 1135 and non-HCHO type biocides Kathon 886 MW (isothiazolone and Preventol CMK 40 (phenolic toward this emerging mycobacterial species (M. immunogenum in HP-linked MWFs, alone and in presence of a representative of the Gram-negative bacterial contaminants, Pseudomonas fluorescens, using two semi-synthetic MWF matrices (designated Fluid A and Fluid B. Relative biocide susceptibility analysis indicated M immunogenum to be comparatively more resistant (2–1600 fold than P. fluorescens to the tested biocides under the varied test conditions. In terms of minimum inhibitory concentration, Kathon was the most effective biocide against M. immunogenum. Fluid factors had a major effect on the biocide susceptibility. Fluid A formulation provided greater protective advantage to the test organisms than Fluid B. Fluid dialysis (Fluid A led to an increased biocidal efficacy of Grotan, Kathon and Preventol against M. immunogenum further implying the role of native fluid components. Used fluid matrix, in general, increased the resistance of the two test organisms against the biocides, with certain exceptions. M. immunogenum resistance increased in presence of the co-contaminant P. fluorescens. Collectively, the results show a multifactorial nature of the biocide susceptibility of MWF-colonizing mycobacteria and highlight the importance of more rigorous efficacy testing and validation of biocides prior to and during their application in metalworking fluid operations.

  17. Expression of Fap amyloids in Pseudomonas aeruginosa, P. fluorescens, and P. putida results in aggregation and increased biofilm formation

    DEFF Research Database (Denmark)

    Dueholm, Morten Simonsen; Søndergaard, Mads; Nilsson, Martin

    2013-01-01

    fluorescens Pf-5, and P. putida F1 to express Fap fibrils, and investigated the effect of Fap expression on aggregation and biofilm formation. The fap operon in all three Pseudomonas species conferred the ability to express Fap fibrils as shown using a recombinant approach. This Fap overexpression consistently......The fap operon, encoding functional amyloids in Pseudomonas (Fap), is present in most pseudomonads, but so far the expression and importance for biofilm formation has only been investigated for P. fluorescens strain UK4. In this study, we demonstrate the capacity of P. aeruginosa PAO1, P...

  18. A phosphate-starvation-inducible outermembrane protein of Pseudomonas fluorescens Ag1 as an immunological phosphate-starvation marker

    DEFF Research Database (Denmark)

    Leopold, Kristine; Jacobsen, Susanne; Nybroe, Ole

    1997-01-01

    A phosphate-starvation-inducible outer-membrane protein of Pseudomonas fluorescens Ag1, expressed at phosphate concentrations below0.08-0.13 mM, was purified and characterized. The purification method involved separation of outer-membrane proteins by SDS-PAGE andextraction of the protein from...... nitrocellulose or PVDF membranes after electrotransfer of proteins to the membranes. The N-terminal amino acidsequence of the purified protein, called Psi1, did not show homology to any known proteins, and in contrast to the phosphate-specific porin OprP ofP. aeruginosa its mobility in SDS-PAGE was not affected...

  19. Extracellular Protease of Pseudomonas fluorescens CHA0, a Biocontrol Factor with Activity against the Root-Knot Nematode Meloidogyne incognita

    OpenAIRE

    Siddiqui, Imran Ali; Haas, Dieter; Heeb, Stephan

    2005-01-01

    In Pseudomonas fluorescens CHA0, mutation of the GacA-controlled aprA gene (encoding the major extracellular protease) or the gacA regulatory gene resulted in reduced biocontrol activity against the root-knot nematode Meloidogyne incognita during tomato and soybean infection. Culture supernatants of strain CHA0 inhibited egg hatching and induced mortality of M. incognita juveniles more strongly than did supernatants of aprA and gacA mutants, suggesting that AprA protease contributes to biocon...

  20. Extracellular Protease of Pseudomonas fluorescens CHA0, a Biocontrol Factor with Activity against the Root-Knot Nematode Meloidogyne incognita

    Science.gov (United States)

    Siddiqui, Imran Ali; Haas, Dieter; Heeb, Stephan

    2005-01-01

    In Pseudomonas fluorescens CHA0, mutation of the GacA-controlled aprA gene (encoding the major extracellular protease) or the gacA regulatory gene resulted in reduced biocontrol activity against the root-knot nematode Meloidogyne incognita during tomato and soybean infection. Culture supernatants of strain CHA0 inhibited egg hatching and induced mortality of M. incognita juveniles more strongly than did supernatants of aprA and gacA mutants, suggesting that AprA protease contributes to biocontrol. PMID:16151170

  1. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe

    Science.gov (United States)

    Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H.

    2015-12-01

    Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp = 200…600 μm, porosity ε = 0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol) = 0 after t = 6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest.

  2. Metabolic and transcriptomic changes induced in Arabidopsis by the rhizobacterium Pseudomonas fluorescens SS101.

    Science.gov (United States)

    van de Mortel, Judith E; de Vos, Ric C H; Dekkers, Ester; Pineda, Ana; Guillod, Leandre; Bouwmeester, Klaas; van Loon, Joop J A; Dicke, Marcel; Raaijmakers, Jos M

    2012-12-01

    Systemic resistance induced in plants by nonpathogenic rhizobacteria is typically effective against multiple pathogens. Here, we show that root-colonizing Pseudomonas fluorescens strain SS101 (Pf.SS101) enhanced resistance in Arabidopsis (Arabidopsis thaliana) against several bacterial pathogens, including Pseudomonas syringae pv tomato (Pst) and the insect pest Spodoptera exigua. Transcriptomic analysis and bioassays with specific Arabidopsis mutants revealed that, unlike many other rhizobacteria, the Pf.SS101-induced resistance response to Pst is dependent on salicylic acid signaling and not on jasmonic acid and ethylene signaling. Genome-wide transcriptomic and untargeted metabolomic analyses showed that in roots and leaves of Arabidopsis plants treated with Pf.SS101, approximately 1,910 genes and 50 metabolites were differentially regulated relative to untreated plants. Integration of both sets of "omics" data pointed to a prominent role of camalexin and glucosinolates in the Pf.SS101-induced resistance response. Subsequent bioassays with seven Arabidopsis mutants (myb51, cyp79B2cyp79B3, cyp81F2, pen2, cyp71A12, cyp71A13, and myb28myb29) disrupted in the biosynthesis pathways for these plant secondary metabolites showed that camalexin and glucosinolates are indeed required for the induction of Pst resistance by Pf.SS101. Also for the insect S. exigua, the indolic glucosinolates appeared to play a role in the Pf.SS101-induced resistance response. This study provides, to our knowledge for the first time, insight into the substantial biochemical and temporal transcriptional changes in Arabidopsis associated with the salicylic acid-dependent resistance response induced by specific rhizobacteria.

  3. Biodegradation of phenol, salicylic acid, benzenesulfonic acid, and iomeprol by Pseudomonas fluorescens in the capillary fringe.

    Science.gov (United States)

    Hack, Norman; Reinwand, Christian; Abbt-Braun, Gudrun; Horn, Harald; Frimmel, Fritz H

    2015-12-01

    Mass transfer and biological transformation phenomena in the capillary fringe were studied using phenol, salicylic acid, benzenesulfonic acid, and the iodinated X-ray contrast agent iomeprol as model organic compounds and the microorganism strain Pseudomonas fluorescens. Three experimental approaches were used: Batch experiments (uniform water saturation and transport by diffusion), in static columns (with a gradient of water saturation and advective transport in the capillaries) and in a flow-through cell (with a gradient of water saturation and transport by horizontal and vertical flow: 2-dimension flow-through microcosm). The reactors employed for the experiments were filled with quartz sand of defined particle size distribution (dp=200...600 μm, porosity ε=0.42). Batch experiments showed that phenol and salicylic acid have a high, whereas benzenesulfonic acid and iomeprol have a quite low potential for biodegradation under aerobic conditions and in a matrix nearly close to water saturation. Batch experiments under anoxic conditions with nitrate as electron acceptor revealed that the biodegradation of the model compounds was lower than under aerobic conditions. Nevertheless, the experiments showed that the moisture content was also responsible for an optimized transport in the liquid phase of a porous medium. Biodegradation in the capillary fringe was found to be influenced by both the moisture content and availability of the dissolved substrate, as seen in static column experiments. The gas-liquid mass transfer of oxygen also played an important role for the biological activity. In static column experiments under aerobic conditions, the highest biodegradation was found in the capillary fringe (e.g. βt/β0 (phenol)=0 after t=6 d) relative to the zone below the water table and unsaturated zone. The highest biodegradation occurred in the flow-through cell experiment where the height of the capillary fringe was largest. Copyright © 2015 Elsevier B.V. All rights

  4. Biosurfactant production by Pseudomonas fluorescens growing on molasses and its application in phenol degradation

    Science.gov (United States)

    Suryantia, Venty; Marliyana, Soerya Dewi; Wulandari, Astri

    2015-12-01

    A molasses based medium for the biosurfactant production by Pseudomonas fluorescens was developed, where the effect of pre-treated of molasses and medium composition were evaluated. Biosurfactant production was followed by measuring optical density (OD), surface tension and emulsifying index (E24) over 12 days of fermentation. The optimum condition for the biosurfactant production was obtained when a medium containing of 8 g/L nutrient broth, 5 g/L NaCl, 1 g/L NH4NO3 and 5% v/v pre-treated molasses with centrifugation was used as media with 3 days of fermentation. The biosurfactant was identified as a rhamnolipid type biosurfactant which had critical micelle concentration (CMC) value of 801 mg/L and was able to reduce the surface tension of the water from 80 mN/m to 51 mN/m. The biosurfactants had water in oil (w/o) emulsion type. Biosurfactant was able to emulsify various hydrocarbons, which were able to decrase the interfacial tension about 50-75% when benzyl chloride, anisaldehyde and palm oil were used as immiscible compounds. The biosurfactant exhibited the E24 value of about 50% and the stable emulsion was reached up to 30 days when lubricant was used as an immiscible compound. Up to 68% of phenol was degraded in the presence of biosurfactant within 15 days, whereas only 56% of phenol was degraded in the absence of biosurfactant. Overall, the results exhibited that molasses are recommended for the rhamnolipids production which possessed good surface-active properties and had potential application in the enhancement of phenol degradation.

  5. IMPACT OF SIPHONING ACTIVITY AND NATURALLY SUSPENDED PARTICLE LOAD ON MUSSEL KILL by PSEUDOMONAS FLUORESCENS

    International Nuclear Information System (INIS)

    Daniel Molloy

    2003-01-01

    Under this USDOE-NETL contract, the bacterium Pseudomonas fluorescens is being developed as a biocontrol agent for zebra mussels. The specific purpose of the contract is to identify biotic and abiotic factors that affect mussel kill. Ingestion of these bacteria by zebra mussels is required to achieve kill, and tests evaluating factors that relate to mussel feeding are contained in this report. Specifically the impact of the following two factors were investigated: (1) Mussel siphoning behavior--In nature, zebra mussels typically have their two shells spread apart and their inhalant siphon tube extended from between their shells for taking food particles into their mantle cavities (Fig. 1). Our tests indicated that there is a direct correlation between mussel siphoning activity and mussel mortality achieved by a bacterial treatment. Therefore, to encourage mussel feeding on bacteria, future pipe treatments within power plants should be carried out using procedures which minimize disturbance to mussel siphoning. 2. Naturally suspended particle loads--Since bacterial cells are lethal only if ingested by mussels, waters containing very high levels of naturally suspended particles might reduce the mortality that can be achieved by a bacterial treatment. If true, this inhibition might occur as a result of particle exclusion, i.e., there could be reduced ingestion of bacterial cells since they represent a reduced percentage of all particles ingested. Our tests indicated that a range of particle concentrations that might naturally exist in a turbid river did not inhibit mussel kill by the bacterial cells, but that an artificially high load of natural particles was capable of causing a reduction in kill. To be conservative, therefore, future pipe treatments should be timed to occur when intake waters have relatively low quantities of naturally suspended particulate matter

  6. IMPACT OF SIPHONING ACTIVITY AND NATURALLY SUSPENDED PARTICLE LOAD ON MUSSEL KILL by PSEUDOMONAS FLUORESCENS

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Molloy

    2003-08-04

    Under this USDOE-NETL contract, the bacterium Pseudomonas fluorescens is being developed as a biocontrol agent for zebra mussels. The specific purpose of the contract is to identify biotic and abiotic factors that affect mussel kill. Ingestion of these bacteria by zebra mussels is required to achieve kill, and tests evaluating factors that relate to mussel feeding are contained in this report. Specifically the impact of the following two factors were investigated: (1) Mussel siphoning behavior--In nature, zebra mussels typically have their two shells spread apart and their inhalant siphon tube extended from between their shells for taking food particles into their mantle cavities (Fig. 1). Our tests indicated that there is a direct correlation between mussel siphoning activity and mussel mortality achieved by a bacterial treatment. Therefore, to encourage mussel feeding on bacteria, future pipe treatments within power plants should be carried out using procedures which minimize disturbance to mussel siphoning. 2. Naturally suspended particle loads--Since bacterial cells are lethal only if ingested by mussels, waters containing very high levels of naturally suspended particles might reduce the mortality that can be achieved by a bacterial treatment. If true, this inhibition might occur as a result of particle exclusion, i.e., there could be reduced ingestion of bacterial cells since they represent a reduced percentage of all particles ingested. Our tests indicated that a range of particle concentrations that might naturally exist in a turbid river did not inhibit mussel kill by the bacterial cells, but that an artificially high load of natural particles was capable of causing a reduction in kill. To be conservative, therefore, future pipe treatments should be timed to occur when intake waters have relatively low quantities of naturally suspended particulate matter.

  7. Impact of mutations in hemA and hemH genes on pyoverdine production by Pseudomonas fluorescens ATCC17400.

    Science.gov (United States)

    Baysse, C; Matthijs, S; Pattery, T; Cornelis, P

    2001-11-27

    A Pseudomonas fluorescens Tn5 mutant, with decreased production of the siderophore pyoverdine, was obtained, with the transposon inserted in the hemA gene coding for glutamyl tRNA reductase, the enzyme that catalyzes the first step of heme biosynthesis. Since this mutant was leaky, a second round of transposition was needed to obtain a second mutant completely auxotrophic for the heme precursor delta-aminolevulinate (ALA). Pyoverdine production by this mutant is ALA-dependent at concentrations above those needed to sustain growth. A transposon mutant in the hemH gene that encodes the enzyme ferrochelatase showing a characteristic red fluorescence upon UV exposure as a result of porphyrins accumulation, was obtained by selecting transconjugants on LB medium containing hemin. The DeltahemH mutant was characterized and the corresponding hemH gene sequenced. Antibodies against P. fluorescens HemH detected the protein both in soluble and membrane fractions of the wild-type and confirmed the absence of the enzyme in the mutant. The DeltahemH mutant failed to produce pyoverdine, but the production of the siderophore was restored by introduction of the Pseudomonas aeruginosa hemH gene in trans. These results indicate that de novo heme biosynthesis is needed for a normal level of siderophore pyoverdine production.

  8. Mycorrhization between Cistus ladanifer L. and Boletus edulis Bull is enhanced by the mycorrhiza helper bacteria Pseudomonas fluorescens Migula.

    Science.gov (United States)

    Mediavilla, Olaya; Olaizola, Jaime; Santos-del-Blanco, Luis; Oria-de-Rueda, Juan Andrés; Martín-Pinto, Pablo

    2016-02-01

    Boletus edulis Bull. is one of the most economically and gastronomically valuable fungi worldwide. Sporocarp production normally occurs when symbiotically associated with a number of tree species in stands over 40 years old, but it has also been reported in 3-year-old Cistus ladanifer L. shrubs. Efforts toward the domestication of B. edulis have thus focused on successfully generating C. ladanifer seedlings associated with B. edulis under controlled conditions. Microorganisms have an important role mediating mycorrhizal symbiosis, such as some bacteria species which enhance mycorrhiza formation (mycorrhiza helper bacteria). Thus, in this study, we explored the effect that mycorrhiza helper bacteria have on the efficiency and intensity of the ectomycorrhizal symbiosis between C. ladanifer and B. edulis. The aim of this work was to optimize an in vitro protocol for the mycorrhizal synthesis of B. edulis with C. ladanifer by testing the effects of fungal culture time and coinoculation with the helper bacteria Pseudomonas fluorescens Migula. The results confirmed successful mycorrhizal synthesis between C. ladanifer and B. edulis. Coinoculation of B. edulis with P. fluorescens doubled within-plant mycorrhization levels although it did not result in an increased number of seedlings colonized with B. edulis mycorrhizae. B. edulis mycelium culture time also increased mycorrhization levels but not the presence of mycorrhizae. These findings bring us closer to controlled B. edulis sporocarp production in plantations.

  9. A combined microcosm and mesocosm approach to examine factors affecting survival and mortality of Pseudomonas fluorescens Ag1 in seawater

    DEFF Research Database (Denmark)

    Ahl, Thomas; Christoffersen, K.; Riemann, B.

    1995-01-01

    Abstract: The survival of Pseudomonas fluorescens Ag1 in seawater of Roskilde Fjord (Denmark) was evaluated by a series of laboratory microcosm and field-based mesocosm experiments. In sterile seawater microcosms, culturability of Ag1 was negatively influenced by high salinity (34 versus 8...

  10. Biosynthesis of the antimicrobial cyclic lipopeptides nunamycin and nunapeptin by Pseudomonas fluorescens strain In5 is regulated by the LuxR-type transcriptional regulator NunF

    DEFF Research Database (Denmark)

    Hennessy, Rosanna Catherine; Phippen, Christopher; Nielsen, Kristian Fog

    2017-01-01

    Nunamycin and nunapeptin are two antimicrobial cyclic lipopeptides (CLPs) produced by Pseudomonas fluorescens In5 and synthesized by nonribosomal synthetases (NRPS) located on two gene clusters designated the nun-nup regulon. Organization of the regulon is similar to clusters found in other CLP-p...

  11. Effect of Two Biological Formulations Based on Bacillus subtilis and Pseudomonas fluorescens on Control of Didymella applanata, the Causal Agent of Red Raspberry Cane Spur Blight

    Directory of Open Access Journals (Sweden)

    Margarita Shternshis

    2016-01-01

    Full Text Available In vitro and in vivo studies were conducted to estimate the efficacy of the two microbial formulations based on Bacillus subtilis Cohn. and Pseudomonas fluorescens Mig. on the fungus Didymella applanata (Niessl. Sacc., the causal agent of red raspberry (Rubus idaeus L. spur blight. In vitro, both bacteria reduced the growth of D. applanata. In inoculation experiments with raspberry canes in two cultivars with different susceptibility to D. applanata, these antagonistic bacteria suppressed fungal development by reducing the lesions area and the number of D. applanata fruiting bodies. Field trials of two biological formulations under natural conditions showed a significant suppression of the disease. B. subtilis and P. fluorescens included in the formulations revealed antagonistic activity towards D. applanata that depended on the red raspberry cultivar and weather conditions. In all cases, B. subtilis showed better results than P. fluorescens in biocontrol of the raspberry spur blight. This study demonstrated for the first time the ability of the biocontrol agents B. subtilis and P. fluorescens to suppress red raspberry cane spur blight, a serious worldwide disease.

  12. Dissolution of fluorapatite by Pseudomonas fluorescens P35 resulting in fluorine release

    Science.gov (United States)

    Zhou, Jianping; Wang, Hongmei; Cravotta, Charles A.; Dong, Qiang; Xiang, Xing

    2017-01-01

    Chemical weathering of fluorine-bearing minerals is widely accepted as the main mechanism for the release of fluorine (F) to groundwater. Here, we propose a potential mechanism of F release via microbial dissolution of fluorapatite (Ca5(PO4)3F), which has been neglected previously. Batch culture experiments were conducted at 30°C with a phosphate-solubilizing bacteria strain, Pseudomonas fluorescens P35, and rock phosphates as the sole source of phosphate for microbial growth in parallel with abiotic controls. Rock phosphates consisted of 55–91% of fluorapatite and 5–10% of dolomite before microbial dissolution as indicated by X-ray diffraction (XRD). Mineral composition and morphology changed after microbial dissolution characterized by the disappearance of dolomite and the development of etched cavities on rock phosphate surfaces. The pH of media used was approximately 7.4 at the beginning and increased gradually to 7.7 in abiotic controls; with the inoculum, the pH decreased to acidic values of 3.7–3.8 after 27 h. Phosphate, calcium, and fluoride were released from the rock phosphate to the acidified medium. At 42 h, the concentration of F reached 8.1–10.3 mg L−1. The elevated F concentration was two times higher than the F levels in groundwater in regions diagnosed with fluorosis, and was toxic to the bacteria, as demonstrated by a precipitous decrease in live cells. Geochemical modeling demonstrated that the oxidation of glucose (the carbon source for microbial growth in the medium) to gluconic acid could decrease the pH to 3.7–3.8 and result in the dissolution of fluorapatite and dolomite. Dolomite and fluorapatite remained unsaturated, while concentrations of dissolved phosphorus (P), calcium (Ca), and F increased throughout the time course Fluorite reached saturation [saturation index (SI) 0.22–0.42] after 42 h in rock phosphate–amended biotic systems. However, fluorite was not detected in XRD patterns of the final residue from

  13. Synthesis of silver nanoparticles by endosymbiont Pseudomonas fluorescens CA 417 and their bactericidal activity.

    Science.gov (United States)

    Syed, Baker; M N, Nagendra Prasad; B L, Dhananjaya; K, Mohan Kumar; S, Yallappa; S, Satish

    2016-12-01

    The present study emphasizes on biogenic synthesis of silver nanoparticles and their bactericidal activity against human and phytopathogens. Nanoparticle synthesis was performed using endosymbiont Pseudomonas fluorescens CA 417 inhabiting Coffea arabica L. Synthesized nanoparticles were characterized using hyphenated spectroscopic techniques such as UV-vis spectroscopy which revealed maximum absorption 425nm. Fourier transform infrared spectroscopy (FTIR) analysis revealed the possible functional groups mediating and stabilizing silver nanoparticles with predominant peaks occurring at 3346 corresponding to hydroxyl group, 1635 corresponding carbonyl group and 680 to aromatic group. X-ray diffraction (XRD) analysis revealed the Bragg's diffraction pattern with distinct peaks at 38° 44°, 64° and 78° revealing the face-centered cubic (fcc) metallic crystal corresponding to the (111), (200), (220) and (311) facets of the crystal planes at 2θ angle. The energy dispersive X-ray spectroscopy (EDS) analysis revealed presence of high intense absorption peak at 3keV is a typical characteristic of nano-crystalline silver which confirmed the presence of elemental silver. TEM analysis revealed the size of the nanoparticles to be in the range 5-50nm with polydisperse nature of synthesized nanoparticles bearing myriad shapes. The particle size determined by Dynamic light scattering (DLS) method revealed average size to be 20.66nm. The synthesized silver nanoparticles exhibited significant antibacterial activity against panel of test pathogens. The results showed Klebsiella pneumoniae (MTCC 7407) and Xanthomonas campestris to be more sensitive among the test human pathogen and phyto-pathogen respectively. The study also reports synergistic effect of silver nanoparticles in combination with kanamycin which displayed increased fold activity up to 58.3% against Klebsiella pneumoniae (MTCC 7407). The results of the present investigation are promising enough and attribute towards

  14. The Effect of Bacteria Colony Pseudomonas fluorescens (UB_Pf1 and Bacillus subtilis (UB_Bs1 on the Mortality of Pratylenchus coffeae (Tylenchida: Pratylenchidae

    Directory of Open Access Journals (Sweden)

    Presti Mardiyani Purwaningtyas

    2016-11-01

    Full Text Available Parasitic Root-Lession nematode of Pratylenchus coffeae can reduce the Indonesian coffee plants productivity. Several studies reported that Pseudomonas fluorescens and Bacillus subtilis endophytic bacteria were antagonistic bacteria to nematode. The objective of this research was to reveal the effectiveness of bacterial colonies density of P. fluorescens (UB_Pf1, B.subtilis (UB BS1, and a combination of both bacteria on nematode mortality using median lethal concentration (LC50 and median lethal time 50 (LT50. The densities of bacteria used in this study were 107, 109, 1011 and 1013 cfu/ml. 35 testing nematodes were used and the mortality was counted at 6, 12, 24, 36, and 48 hours after treatments. The results showed that LC50 values of P. fluorescens was (UB_Pf1 was 4,3x108 cfu/ml, LC50 B. subtilis (UB_Bs1 was 1,9x109cfu/ ml, and LC50 combination of both bacteria was, 8x107 cfu/ml. It implies that the application of the combination of both bacteria are more pathogenic than single bacterial treatment. The results also showed that the highest LT50 value was 13.21  hours combination of bacterial colonies with a density of 1013 cfu/ml and the lowest LT50 value was 52.00 hours on P. fluorescens (UB_Pf1 treatment with colonies density of 107 cfu/ml.How to CitePurwaningtyas, P. M., Rahardjo, B. T., & Tarno, H. (2016. The Effect of Bacteria Colony Pseudomonas fluorescens (UB_Pf1 and Bacillus subtilis (UB_Bs1 on the Mortality of Pratylenchus coffeae (Tylenchida: Pratylenchidae. Biosaintifika: Journal of Biology & Biology Education, 8(3, 286-293. 

  15. Isolation and identification of plant growth promoting rhizobacteria from maize (Zea mays L. rhizosphere and their plant growth promoting effect on rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Karnwal Arun

    2017-06-01

    Full Text Available The use of plant growth promoting rhizobacteria is increasing in agriculture and gives an appealing manner to replace chemical fertilizers, pesticides, and dietary supplements. The objective of our research was to access the plant growth promotion traits of Pseudomonas aeruginosa, P. fluorescens and Bacillus subtilis isolated from the maize (Zea mays L. rhizosphere. In vitro studies showed that isolates have the potential to produce indole acetic acid (IAA, hydrogen cyanide, phosphate solubilisation, and siderophore. RNA analysis revealed that two isolates were 97% identical to P. aeruginosa strain DSM 50071 and P. aeruginosa strain NBRC 12689 (AK20 and AK31, while two others were 98% identical to P. fluorescens strain ATCC 13525, P. fluorescens strain IAM 12022 (AK18 and AK45 and one other was 99% identical to B. subtilis strain NCDO 1769 (AK38. Our gnotobiotic study showed significant differences in plant growth variables under control and inoculated conditions. In the present research, it was observed that the isolated strains had good plant growth promoting effects on rice.

  16. Metallo-β-Lactamases in Clinical Pseudomonas Isolates in Taiwan and Identification of VIM-3, a Novel Variant of the VIM-2 Enzyme

    OpenAIRE

    Yan, Jing-Jou; Hsueh, Po-Ren; Ko, Wen-Chien; Luh, Kwen-Tay; Tsai, Shu-Huei; Wu, Hsiu-Mei; Wu, Jiunn-Jong

    2001-01-01

    A total of 209 clinical isolates of Pseudomonas (193 Pseudomonas aeruginosa, 10 P. putida, 4 P. stutzeri, and 2 P. fluorescens isolates) with reduced susceptibilities to imipenem and/or ceftazidime were subjected to PCR assays with primers specific for blaIMP-1, blaIMP-2, blaVIM-1, and blaVIM-2 and sequence analysis to identify the metallo-β-lactamases (MBLs) prevalent among these organisms in Taiwan; and 21 isolates gave positive results. Five isolates including two P. putida and three P. st...

  17. An alternative physiological role for the EmhABC efflux pump in Pseudomonas fluorescens cLP6a

    Directory of Open Access Journals (Sweden)

    Adebusuyi Abigail A

    2011-11-01

    Full Text Available Abstract Background Efflux pumps belonging to the resistance-nodulation-division (RND superfamily in bacteria are involved in antibiotic resistance and solvent tolerance but have an unknown physiological role. EmhABC, a RND-type efflux pump in Pseudomonas fluorescens strain cLP6a, extrudes hydrophobic antibiotics, dyes and polycyclic aromatic hydrocarbons including phenanthrene. The effects of physico-chemical factors such as temperature or antibiotics on the activity and expression of EmhABC were determined in order to deduce its physiological role(s in strain cLP6a in comparison to the emhB disruptant strain, cLP6a-1. Results Efflux assays conducted with 14C-phenanthrene showed that EmhABC activity is affected by incubation temperature. Increased phenanthrene efflux was measured in cLP6a cells grown at 10°C and decreased efflux was observed at 35°C compared with cells grown at the optimum temperature of 28°C. Membrane fatty acids in cLP6a cells were substantially altered by changes in growth temperature and in the presence of tetracycline. Changed membrane fatty acids and increased membrane permeability were associated with ~30-fold increased expression of emhABC in cLP6a cells grown at 35°C, and with increased extracellular free fatty acids. Growth of P. fluorescens cLP6a at supra-optimal temperature was enhanced by the presence of EmhABC compared to strain cLP6a-1. Conclusions Combined, these observations suggest that the EmhABC efflux pump may be involved in the management of membrane stress effects such as those due to unfavourable incubation temperatures. Efflux of fatty acids replaced as a result of membrane damage or phospholipid turnover may be the primary physiological role of the EmhABC efflux pump in P. fluorescens cLP6a.

  18. Kinetics of Enantiomerically Enriched Synthesis of Solketal Esters Using Native and SBA-15 supported P. Fluorescens Lipase

    Directory of Open Access Journals (Sweden)

    Zniszczoł Aurelia

    2017-06-01

    Full Text Available The studies showed that alkaline lipase from Pseudomonas fluorescens enables an irreversible transesterification of vinyl esters to give enantiomeric excess (eeR of about 80% using vinyl butyrate as acyl donor and diisopropyl ether as a solvent, at partially optimized conditions. For the native lipase the process was adequately described by a five-parameter Ping-Pong Bi Bi model for both enantiomers plus expression accounting for the formation of enzyme-acyl donor complex, but for the same lipase supported on mesoporous materials of SBA-15-Oc type, R-product inhibition also had to be taken into account. The use of hydrophobic support increased by more than two-fold the rate of the S-solketal conversion but even more that of R-solketal. Thus the immobilization of lipase had very positive effect on the process kinetics but decreased its enantioselectivity.

  19. Cloning and expression of Pseudomonas fluorescens 26-2 lipase gene in Pichia pastoris and characterizing for transesterification.

    Science.gov (United States)

    Yang, Jiangke; Zhang, Bo; Yan, Yunjun

    2009-11-01

    Pseudomonas lipases are important biocatalysts widely used in a variety of industrial fields. An extracellular lipase gene lipA with 1,854-bp open reading frame was cloned from Pseudomonas fluorescens 26-2. The multialignment assay of the putative amino acid and the secondary structure prediction revealed this enzyme could be classified into the lipolytic subfamily I.3 and secreted via adenosine-triphosphate-binding cassette pathway. The lipA gene was integrated into Pichia pastoris GS115, and the methanol-inducible recombinants with Mut(S) and Mut(+) phenotypes were acquired. The characteristics and the transesterification capacity shown by this enzyme suggested it is a useful biocatalyst for biodiesel preparation.

  20. Pseudomonas fluorescens Pf-5 genome-wide mutant screen for resistance to the antimicrobial peptide alfalfa snakin-1.

    Science.gov (United States)

    Ayub, Nicolás D; Fox, Ana R; García, Araceli N; Mozzicafreddo, Matteo; Cuccioloni, Massimiliano; Angeletti, Mauro; Pagano, Elba; Soto, Gabriela

    2015-01-01

    Snakin-1, a peptide produced by higher plants, has broad-spectrum antibiotic activity, inhibiting organisms ranging from Bacteria to Eukaryotes. However, the mode of action against target organisms is poorly understood. As a first step to elucidate the mechanism, we screened a mutation library of Pseudomonas fluorescens Pf-5 in LB and agar medium supplemented with alfalfa snakin-1 (MsSN1). We identified three biofilm formation-related Pseudomonas mutants that showed increased resistance to MsSN1. Genetic, physiological and bioinformatics analysis validated the results of the mutant screens, indicating that bacterial adhesion protein lapA is probably the target of MsSN1. Collectively, these findings suggest that snakin-1 acts on microbial adhesion properties. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. Exposure-related effects of Pseudomonas fluorescens, strain CL145A, on coldwater, coolwater, and warmwater fish

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Denise A. Mayer,

    2015-01-01

    The exposure-related effects of a commercially prepared spray-dried powder (SDP) formulation of Pseudomonas fluorescens, strain CL145A, were evaluated on coldwater, coolwater, and warmwater fish endemic to the Great Lakes and Upper Mississippi River Basins. Nine species of young-of-the-year fish were exposed to SDP for 24 hours by using continuous-flow, serial-dilution exposure systems at temperatures of 12 degrees Celsius (°C; 2 species; Oncorhynchus mykiss [rainbow trout] and Salvelinus fontinalis [brook trout]), 17 °C (3 species; Perca flavescens [yellow perch], Sander vitreus [walleye], and Acipenser fulvescens [lake sturgeon]), or 22 °C (4 species; Micropterus salmoides [largemouth bass], Micropterus dolomieu [smallmouth bass], Lepomis macrochirus [bluegill sunfish], and Ictalurus punctatus [channel catfish]).

  2. Identification of anthranilate and benzoate metabolic operons of Pseudomonas fluorescens and functional characterization of their promoter regions

    Directory of Open Access Journals (Sweden)

    Lee Vincent D

    2006-01-01

    Full Text Available Abstract Background In an effort to identify alternate recombinant gene expression systems in Pseudomonas fluorescens, we identified genes encoding two native metabolic pathways that were inducible with inexpensive compounds: the anthranilate operon (antABC and the benzoate operon (benABCD. Results The antABC and benABCD operons were identified by homology to the Acinetobacter sp. anthranilate operon and Pseudomonas putida benzoate operon, and were confirmed to be regulated by anthranilate or benzoate, respectively. Fusions of the putative promoter regions to the E. coli lacZ gene were constructed to confirm inducible gene expression. Each operon was found to be controlled by an AraC family transcriptional activator, located immediately upstream of the first structural gene in each respective operon (antR or benR. Conclusion We have found the anthranilate and benzoate promoters to be useful for tightly controlling recombinant gene expression at both small (

  3. Controlling instability in gacS-gacA regulatory genes during inoculant production of Pseudomonas fluorescens biocontrol strains.

    Science.gov (United States)

    Duffy, B K; Défago, G

    2000-08-01

    Secondary metabolism in fluorescent pseudomonads is globally regulated by gacS, which encodes a membrane-bound sensor kinase, and gacA, which encodes a transcriptional response regulator. Spontaneous mutation in either gene blocked biosynthesis of the antimicrobial compounds hydrogen cyanide, 2,4-diacetylphloroglucinol, pyoluteorin, and pyrrolnitrin by the model biocontrol strain Pseudomonas fluorescens CHA0. Spontaneous mutants also had altered abilities to utilize several carbon sources and to increase medium pH compared with the wild type, suggesting that gacS and gacA influence primary as well as secondary bacterial metabolism. Inoculant efficacy for biocontrol was significantly reduced by contamination with regulatory mutants which accumulated during inoculum production. Spontaneous mutants accumulated in all 192 separate liquid cultures examined, typically at a frequency of 1% or higher after 12 days. During scale-up in a simulated industrial fermentation process, mutants increased exponentially and accounted for 7, 23, and 61% of the total viable cells after transfer to 20-, 100-, and 500-ml preparations, respectively. GacS(-) and GacA(-) mutants had identical phenotypes and occurred at the same frequency, indicating that the selective pressures for the two mutants were similar. We developed a simple screening method for monitoring inoculant quality based on the distinctive appearance of mutant colonies (i.e., orange color, enlarged diameter, hyperfluorescence). Mutant competitiveness was favored in a nutrient-rich medium with a high electrolyte concentration (nutrient broth containing yeast extract). We were able to control mutant accumulation and to clean up contaminated cultures by using certain mineral amendments (i.e., zinc, copper, cobalt, manganese, and ammonium molybdate) or by diluting media 1/10. Spontaneous mutants and genetic constructs had the same response to culture conditions. Zinc and medium dilution were also effective for improving the

  4. The Pseudomonas fluorescens Siderophore Pyoverdine Weakens Arabidopsis thaliana Defense in Favor of Growth in Iron-Deficient Conditions.

    Science.gov (United States)

    Trapet, Pauline; Avoscan, Laure; Klinguer, Agnès; Pateyron, Stéphanie; Citerne, Sylvie; Chervin, Christian; Mazurier, Sylvie; Lemanceau, Philippe; Wendehenne, David; Besson-Bard, Angélique

    2016-05-01

    Pyoverdines are siderophores synthesized by fluorescent Pseudomonas spp. Under iron-limiting conditions, these high-affinity ferric iron chelators are excreted by bacteria in the soil to acquire iron. Pyoverdines produced by beneficial Pseudomonas spp. ameliorate plant growth. Here, we investigate the physiological incidence and mode of action of pyoverdine from Pseudomonas fluorescens C7R12 on Arabidopsis (Arabidopsis thaliana) plants grown under iron-sufficient or iron-deficient conditions. Pyoverdine was provided to the medium in its iron-free structure (apo-pyoverdine), thus mimicking a situation in which it is produced by bacteria. Remarkably, apo-pyoverdine abolished the iron-deficiency phenotype and restored the growth of plants maintained in the iron-deprived medium. In contrast to a P. fluorescens C7R12 strain impaired in apo-pyoverdine production, the wild-type C7R12 reduced the accumulation of anthocyanins in plants grown in iron-deficient conditions. Under this condition, apo-pyoverdine modulated the expression of around 2,000 genes. Notably, apo-pyoverdine positively regulated the expression of genes related to development and iron acquisition/redistribution while it repressed the expression of defense-related genes. Accordingly, the growth-promoting effect of apo-pyoverdine in plants grown under iron-deficient conditions was impaired in iron-regulated transporter1 and ferric chelate reductase2 knockout mutants and was prioritized over immunity, as highlighted by an increased susceptibility to Botrytis cinerea This process was accompanied by an overexpression of the transcription factor HBI1, a key node for the cross talk between growth and immunity. This study reveals an unprecedented mode of action of pyoverdine in Arabidopsis and demonstrates that its incidence on physiological traits depends on the plant iron status. © 2016 American Society of Plant Biologists. All Rights Reserved.

  5. The Pseudomonas fluorescens Siderophore Pyoverdine Weakens Arabidopsis thaliana Defense in Favor of Growth in Iron-Deficient Conditions1

    Science.gov (United States)

    Trapet, Pauline; Avoscan, Laure; Klinguer, Agnès; Pateyron, Stéphanie; Chervin, Christian; Mazurier, Sylvie; Lemanceau, Philippe; Wendehenne, David; Besson-Bard, Angélique

    2016-01-01

    Pyoverdines are siderophores synthesized by fluorescent Pseudomonas spp. Under iron-limiting conditions, these high-affinity ferric iron chelators are excreted by bacteria in the soil to acquire iron. Pyoverdines produced by beneficial Pseudomonas spp. ameliorate plant growth. Here, we investigate the physiological incidence and mode of action of pyoverdine from Pseudomonas fluorescens C7R12 on Arabidopsis (Arabidopsis thaliana) plants grown under iron-sufficient or iron-deficient conditions. Pyoverdine was provided to the medium in its iron-free structure (apo-pyoverdine), thus mimicking a situation in which it is produced by bacteria. Remarkably, apo-pyoverdine abolished the iron-deficiency phenotype and restored the growth of plants maintained in the iron-deprived medium. In contrast to a P. fluorescens C7R12 strain impaired in apo-pyoverdine production, the wild-type C7R12 reduced the accumulation of anthocyanins in plants grown in iron-deficient conditions. Under this condition, apo-pyoverdine modulated the expression of around 2,000 genes. Notably, apo-pyoverdine positively regulated the expression of genes related to development and iron acquisition/redistribution while it repressed the expression of defense-related genes. Accordingly, the growth-promoting effect of apo-pyoverdine in plants grown under iron-deficient conditions was impaired in iron-regulated transporter1 and ferric chelate reductase2 knockout mutants and was prioritized over immunity, as highlighted by an increased susceptibility to Botrytis cinerea. This process was accompanied by an overexpression of the transcription factor HBI1, a key node for the cross talk between growth and immunity. This study reveals an unprecedented mode of action of pyoverdine in Arabidopsis and demonstrates that its incidence on physiological traits depends on the plant iron status. PMID:26956666

  6. Conversion of Sterically Demanding α,α-Disubstituted Phenylacetonitriles by the Arylacetonitrilase from Pseudomonas fluorescens EBC191

    Science.gov (United States)

    Baum, Stefanie; Williamson, Dael S.; Sewell, Trevor

    2012-01-01

    The nitrilase from Pseudomonas fluorescens EBC191 converted 2-methyl-2-phenylpropionitrile, which contains a quaternary carbon atom in the α-position toward the nitrile group, and also similar sterically demanding substrates, such as 2-hydroxy-2-phenylpropionitrile (acetophenone cyanohydrin) or 2-acetyloxy-2-methylphenylacetonitrile. 2-Methyl-2-phenylpropionitrile was hydrolyzed to almost stoichiometric amounts of the corresponding acid. Acetophenone cyanohydrin was transformed to the corresponding acid (atrolactate) and amide (atrolactamide) at a ratio of about 3.4:1. The (R)-acid and the (S)-amide were formed preferentially from acetophenone cyanohydrin. A homology model of the nitrilase suggested that steric hindrance with amino acid residue Tyr54 could impair the binding or conversion of sterically demanding substrates. Therefore, several enzyme variants that carried mutations in the respective residues were generated and subsequently analyzed for the substrate specificity and enantioselectivity of the reactions. Enzyme variants that demonstrated increased relative activities for the conversion of acetophenone cyanohydrin were identified. The chiral analysis of these reactions demonstrated peculiar reaction kinetics, which suggested that the enzyme variants converted the nonpreferred (S)-enantiomer of acetophenone cyanohydrin with a higher reaction rate than that of the (preferred) (R)-enantiomer. Recombinant whole-cell catalysts that simultaneously produced the nitrilase from P. fluorescens EBC191 and a plant-derived (S)-oxynitrilase from cassava (Manihot esculenta) converted acetophenone plus cyanide at pH 4.5 to (S)-atrolactate and (S)-atrolactamide. These recombinant cells are promising catalysts for the synthesis of stable chiral quaternary carbon centers from ketones. PMID:22020513

  7. Efficiency of the formulated plant-growth promoting Pseudomonas fluorescens MC46 inoculant on triclocarban treatment in soil and its effect on Vigna radiata growth and soil enzyme activities.

    Science.gov (United States)

    Sipahutar, Merry Krisdawati; Piapukiew, Jittra; Vangnai, Alisa S

    2018-02-15

    For bioaugmentation-based treatment of triclocarban (TCC), an emerging soil pollutant that is recalcitrant to biodegradation and phytotransformation, efficient TCC-degrading bacteria with an effective soil-delivering means are required. This work developed the formulated bacterial inoculant, and successfully demonstrated its TCC removal and detoxification performance in pot soil experiment with Vigna radiata plants. The soil bacterium Pseudomonas fluorescens MC46 was isolated as TCC-degrading, plant-growth promoting bacterium. The characterizations were conducted in vitro revealing that it could utilize TCC as a sole carbon source, and at a wide and higher concentration range from 1.6-31.6mgkg -1 than those previously reported, while the detoxification was assessed by cytogenotoxicity and phytotoxicity tests. The developed sawdust-based inoculant formula combined with molasses (5% w/w), and either PEG or CMC-starch blend (1% w/w) could maintain a 20-week shelf-life inoculant stability in terms of cell viability, and TCC-degrading activity. Bioaugmentation of the formulated inoculants into TCC-contaminated soil efficiently removed TCC up to 74-76% of the initial concentration, mitigated toxicity, restored plant growth and health, and enhanced soil enzyme activities. This work is the first to demonstrate potential application of the formulated plant-growth promoting bacterial inoculant for the treatment and detoxification of a persistent TCC contaminated in soil. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Diversity of Pseudomonas Genomes, Including Populus-Associated Isolates, as Revealed by Comparative Genome Analysis.

    Science.gov (United States)

    Jun, Se-Ran; Wassenaar, Trudy M; Nookaew, Intawat; Hauser, Loren; Wanchai, Visanu; Land, Miriam; Timm, Collin M; Lu, Tse-Yuan S; Schadt, Christopher W; Doktycz, Mitchel J; Pelletier, Dale A; Ussery, David W

    2016-01-01

    The Pseudomonas genus contains a metabolically versatile group of organisms that are known to occupy numerous ecological niches, including the rhizosphere and endosphere of many plants. Their diversity influences the phylogenetic diversity and heterogeneity of these communities. On the basis of average amino acid identity, comparative genome analysis of >1,000 Pseudomonas genomes, including 21 Pseudomonas strains isolated from the roots of native Populus deltoides (eastern cottonwood) trees resulted in consistent and robust genomic clusters with phylogenetic homogeneity. All Pseudomonas aeruginosa genomes clustered together, and these were clearly distinct from other Pseudomonas species groups on the basis of pangenome and core genome analyses. In contrast, the genomes of Pseudomonas fluorescens were organized into 20 distinct genomic clusters, representing enormous diversity and heterogeneity. Most of our 21 Populus-associated isolates formed three distinct subgroups within the major P. fluorescens group, supported by pathway profile analysis, while two isolates were more closely related to Pseudomonas chlororaphis and Pseudomonas putida. Genes specific to Populus-associated subgroups were identified. Genes specific to subgroup 1 include several sensory systems that act in two-component signal transduction, a TonB-dependent receptor, and a phosphorelay sensor. Genes specific to subgroup 2 contain hypothetical genes, and genes specific to subgroup 3 were annotated with hydrolase activity. This study justifies the need to sequence multiple isolates, especially from P. fluorescens, which displays the most genetic variation, in order to study functional capabilities from a pangenomic perspective. This information will prove useful when choosing Pseudomonas strains for use to promote growth and increase disease resistance in plants. Copyright © 2015 Jun et al.

  9. Identification of copper-induced genes in Pseudomonas fluorescens and use of a reporter strain to monitor bioavailable copper in soil

    DEFF Research Database (Denmark)

    Tom-Petersen, Andreas; Hosbond, Carsten; Nybroe, Ole

    2001-01-01

    negatively affect the bacterial soil community. In this study, our goal was to develop a specific and stable Cu reporter construction harboured by an indigenous soil bacterium to measure bioavailability of Cu in soil. Following mutagenesis of Pseudomonas fluorescens strain DF57 with a Tn5::luxAB promoter......-Cu15, the gene interrupted by the transposon encoded a protein carrying a Cu-binding domain but with low homology to known proteins. DF57-Cu15 was the most suitable Cu reporter due to its high specific response and tolerance to Cu in pure culture. DF57-Cu15 responded to soil solutions from Cu......-amended soil microcosms in a concentration-dependent manner. The chelator EDTA reduced the availability of Cu to P. fluorescens in soil. This showed that complex-bound Cu is not necessarily available to bacteria, We compared chemical analysis of soluble Cu and the reporter assay on soil solutions from Cu...

  10. Identification of the minimal region in lipase ABC transporter recognition domain of Pseudomonas fluorescens for secretion and fluorescence of green fluorescent protein

    Directory of Open Access Journals (Sweden)

    Park Yeonwoo

    2012-05-01

    Full Text Available Abstract Background TliA is a thermostable lipase secreted by the type 1 secretion system (T1SS of Pseudomonas fluorescens. The secretion is promoted by its secretion/chaperone domain located near the C-terminus, which is composed mainly of four Repeat-in-Toxin (RTX repeats. In order to identify the minimal region of TliA responsible for its secretion, five different copies of the secretion/chaperone domain, each involving truncated N-terminal residues and a common C-terminus, were acquired and named as lipase ABC transporter recognition domains (LARDs. Each LARD was fused to epidermal growth factor (EGF or green fluorescent protein (GFP, and the secretion of EGF-LARD or GFP-LARD fusion proteins was assessed in Escherichia coli with ABC transporter. Results Among the fusion proteins, GFP or EGF with 105-residue LARD3 was most efficiently secreted. In addition, GFP-LARD3 emitted wild type GFP fluorescence. Structurally, LARD3 had the 4 RTX repeats exposed at the N-terminus, while other LARDs had additional residues prior to them or missed some of the RTX repeats. LARD3 was both necessary and sufficient for efficient secretion and maintenance of GFP fluorescence in E. coli, which was also confirmed in P. fluorescens and P. fluorescens ▵tliA, a knock-out mutant of tliA. Conclusion LARD3 was a potent secretion signal in T1SS for its fusion flanking RTX motif, which enhanced secretion and preserved the fluorescence of GFP. LARD3-mediated secretion in E. coli or P. fluorescens will enable the development of enhanced protein manufacturing factory and recombinant microbe secreting protein of interest in situ.

  11. The role of the antimicrobial compound 2,4-diacetylphloroglucinol in the impact of biocontrol Pseudomonas fluorescens F113 on Azospirillum brasilense phytostimulators.

    Science.gov (United States)

    Couillerot, Olivier; Combes-Meynet, Emeline; Pothier, Joël F; Bellvert, Floriant; Challita, Elita; Poirier, Marie-Andrée; Rohr, René; Comte, Gilles; Moënne-Loccoz, Yvan; Prigent-Combaret, Claire

    2011-06-01

    Pseudomonads producing the antimicrobial metabolite 2,4-diacetylphloroglucinol (Phl) can control soil-borne phytopathogens, but their impact on other plant-beneficial bacteria remains poorly documented. Here, the effects of synthetic Phl and Phl(+) Pseudomonas fluorescens F113 on Azospirillum brasilense phytostimulators were investigated. Most A. brasilense strains were moderately sensitive to Phl. In vitro, Phl induced accumulation of carotenoids and poly-β-hydroxybutyrate-like granules, cytoplasmic membrane damage and growth inhibition in A. brasilense Cd. Experiments with P. fluorescens F113 and a Phl(-) mutant indicated that Phl production ability contributed to in vitro growth inhibition of A. brasilense Cd and Sp245. Under gnotobiotic conditions, each of the three strains, P. fluorescens F113 and A. brasilense Cd and Sp245, stimulated wheat growth. Co-inoculation of A. brasilense Sp245 and Pseudomonas resulted in the same level of phytostimulation as in single inoculations, whereas it abolished phytostimulation when A. brasilense Cd was used. Pseudomonas Phl production ability resulted in lower Azospirillum cell numbers per root system (based on colony counts) and restricted microscale root colonization of neighbouring Azospirillum cells (based on confocal microscopy), regardless of the A. brasilense strain used. Therefore, this work establishes that Phl(+) pseudomonads have the potential to interfere with A. brasilense phytostimulators on roots and with their plant growth promotion capacity.

  12. Investigating the ability of Pseudomonas fluorescens UW4 to reduce cadmium stress in Lactuca sativa via an intervention in the ethylene biosynthetic pathway.

    Science.gov (United States)

    Albano, Lucas J; Macfie, Sheila M

    2016-12-01

    A typical plant response to any biotic or abiotic stress, including cadmium (Cd), involves increased ethylene synthesis, which causes senescence of the affected plant part. Stressed plants can experience reduced ethylene and improved growth if they are inoculated with bacteria that have the enzyme ACC deaminase, which metabolizes the ethylene precursor ACC (1-aminocyclopropane-1-carboxylate). We investigated whether one such bacterium, Pseudomonas fluorescens UW4, reduces the production of ethylene and improves the growth of lettuce (Lactuca sativa) sown in Cd-contaminated potting material (PRO-MIX® BX). Plants were inoculated with the wild-type P. fluorescens UW4 or a mutant strain that cannot produce ACC deaminase. Cadmium-treated plants contained up to 50 times more Cd than did control plants. In noninoculated plants, Cd induced a 5-fold increase in ethylene concentration. The wild-type bacterium prevented Cd-induced reductions in root biomass but there was no relationship between Cd treatment and ethylene production in inoculated plants. In contrast, when the concentration of ethylene was plotted against the extent of bacterial colonization of the roots, increased colonization with wild-type P. fluorescens UW4 was associated with 20% less ethylene production. Ours is the first study to show that the protective effect of this bacterium is proportional to the quantity of bacteria on the root surface.

  13. Quantitative and qualitative variability of the caseinolytic potential of different strains of Pseudomonas fluorescens: implications for the stability of casein micelles of UHT milks during their storage.

    Science.gov (United States)

    Baglinière, François; Tanguy, Gaëlle; Jardin, Julien; Matéos, Aurélie; Briard, Valérie; Rousseau, Florence; Robert, Benoît; Beaucher, Eric; Humbert, Gérard; Dary, Annie; Gaillard, Jean Luc; Amiel, Caroline; Gaucheron, Frédéric

    2012-12-15

    Pseudomonas fluorescens grows at low temperature and produces thermo-resistant protease(s) that can destabilize UHT (Ultra High Temperature) milk during its storage. The consequences of contamination of microfiltered milk with 9 strains of P. fluorescens on the stability of the corresponding UHT milk during storage had been investigated in this study. The strains were classified in two groups according to their ability to destabilize UHT milk. For the group of highly destabilizing strains, sedimentations of UHT milks, low values to phosphate test and the presence of aggregates were observed. Zeta potential and hydration of casein micelles decreased, whereas non casein nitrogen (NCN) and non protein nitrogen (NPN) contents increased. The analyses of NCN fraction by liquid chromatography coupled to mass spectrometry indicated that the different casein molecules were hydrolyzed in a similar way for the destabilizing strains suggesting that the same enzyme was implicated. For the group of slightly or not destabilizing strains no visual and biochemical alteration were found. This study showed that destabilization of UHT milk by P. fluorescens was highly variable and strain-dependent. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Structure of a putative BenF-like porin from Pseudomonas fluorescens Pf-5 at 2.6 A resolution

    Energy Technology Data Exchange (ETDEWEB)

    Sampathkumar, P.; Swaminathan, S.; Lu, F.; Zhao, X.; Li, Z.; Gilmore, J.; Bain, K.; Rutter, M. E.; Gheyi, T.; Schwinn, D.; Bonanno, J. B.; Pieper, U.; Fajardo, J. E.; Fiser, A.; Almo, S. C.; Chance, M. R.; Baker, D.; Atwell, S.; Thompson, D. A.; Emtage, J. S.; Wasserman, S. R.; Sali, A.; Sauder, J. M.; Burley, S. K.

    2010-11-01

    Gram-negative bacteria typically overcome poor permeability of outer membranes through general porins like OmpF and OmpC, which form water-filled transmembrane pores permitting diffusion of hydrophilic molecules with no particular selectivity. Many bacteria lacking such general porins use substrate-specific porins to overcome growth-limiting conditions and facilitate selective transport of metabolites. Exclusive reliance on substrate-specific porins yields lower membrane permeability to small molecules (<600 Da) versus that seen for Escherichia coli. In Pseudomonads, transit of most small molecules across the cell membrane is thought to be mediated by substrate-specific channels of the OprD superfamily. This property explains, at least in part, the high incidence of Pseudomonas aeruginosa antibiotic resistance. High-throughput DNA sequencing of the P. aeruginosa chromosome revealed the presence of 19 genes encoding structurally related, substrate-specific porins (with 30-45% pairwise amino acid sequence identity) that mediate transmembrane passage of small, water-soluble compounds. The OprD superfamily encompasses the eponymous OprD subfamily, which includes 9 P. aeruginosa proteins that convey basic amino acids and carbapenem antibiotics, and the OpdK subfamily, which includes 11 P. aeruginosa proteins that convey aromatic acids and other small aromatic compounds. Genome sequencing of other gram-negative bacteria has revealed additional members of the OprD and OpdK subfamilies in various organisms, including other pseudomonads. Among the many bacteria in which OprD superfamily members have been identified are P. putida, P. fluorescens Pf-5, P. syringae, and Azotobacter vinelandii, all of which share closely related genes that encode the so-called BenF-like porins. In P. putida, benF is part of an operon involved in benzoate catabolism regulated by benR. Within this operon, benK, benE, and benF genes have been suggested to contribute toward either influx or efflux

  15. Ability of the marine bacterium Pseudomonas fluorescens BA3SM1 to counteract the toxicity of CdSe nanoparticles.

    Science.gov (United States)

    Poirier, Isabelle; Kuhn, Lauriane; Demortière, Arnaud; Mirvaux, Boris; Hammann, Philippe; Chicher, Johana; Caplat, Christelle; Pallud, Marie; Bertrand, Martine

    2016-10-04

    In the marine environment, bacteria from estuarine and coastal sediments are among the first targets of nanoparticle pollution; it is therefore relevant to improve the knowledge of interactions between bacteria and nanoparticles. In this work, the response of the marine bacterium Pseudomonas fluorescens BA3SM1 to CdSe nanocrystals (CdSe NPs) of 3nm (NP3) and 8nm (NP8) in diameter was evaluated through microscopic, physiological, biochemical and proteomic approaches. Transmission electron microscopy images showed that NP3 were able to penetrate the bacteria, while NP8 were highly concentrated around the cells, embedded in large exopolysaccharides. In our experimental conditions, both CdSe NP sizes induced a decrease in respiration during the stationary growth phase, while only NP8 caused growth retardation and a decrease in pyoverdine production. Proteomic analyses highlighted that the strain responded to CdSe NP toxicity by inducing various defence mechanisms such as cell aggregation, extracellular CdSe NP sequestration, effective protection against oxidative stress, modifications of envelope organization and properties, and cadmium export. In addition, BA3SM1 presented a biosorption capacity of 1.6×10(16)NP3/g dry weight and 1.7×10(15)NP8/g dry weight. This strain therefore appears as a promising agent for NP bioremediation processes. Proteomic data are available via ProteomeXchange with identifier PXD004012. To the best of our knowledge, this is the first report focussing on the effects of CdSe colloidal nanocrystals (CdSe NPs) on a marine strain of Pseudomonas fluorescens. CdSe NPs are extensively used in the industry of renewable energies and it is regrettably expected that these pollutants will sometime soon appear in the marine environment through surface runoff, urban effluents and rivers. Bacteria living in estuarine and coastal sediments will be among the first targets of these new pollutants. The pseudomonads are frequently found in these ecosystems

  16. Isolation and Identification of Sodium Fluoroacetate Degrading Bacteria from Caprine Rumen in Brazil

    OpenAIRE

    Expedito K. A. Camboim; Arthur P. Almeida; Michelle Z. Tadra-Sfeir; Felício G. Junior; Paulo P. Andrade; Chris S. McSweeney; Marcia A. Melo; Franklin Riet-Correa

    2012-01-01

    The objective of this paper was to report the isolation of two fluoroacetate degrading bacteria from the rumen of goats. The animals were adult goats, males, crossbred, with rumen fistula, fed with hay, and native pasture. The rumen fluid was obtained through the rumen fistula and immediately was inoculated 100  μ L in mineral medium added with 20 mmol L−1 sodium fluoroacetate (SF), incubated at 39°C in an orbital shaker. Pseudomonas fluorescens (strain DSM 8341) was used as positive control ...

  17. Impact of Medium on the Development and Physiology of Pseudomonas fluorescens Biofilms on Polyurethane Paint

    Science.gov (United States)

    2012-02-01

    1989). In Pseudomonas putida , increasing glucose and phosphate concentrations Approved for public release; distribution unlimited 14 increased...polyhydroxyalkanoates in Pseudomonas putida KT2442 and the fundamental role of PhaZ depolymerase for the metabolic balance. Environ Microbiol. 12(1...Effects of nutrients on biofilm formation and detachment of a Pseudomonas putida strain isolated from a paper machine. Water Res. 41(13):2885-2892

  18. Genome-wide analysis of bacterial determinants of plant growth promotion and induced systemic resistance by Pseudomonas fluorescens.

    Science.gov (United States)

    Cheng, Xu; Etalo, Desalegn W; van de Mortel, Judith E; Dekkers, Ester; Nguyen, Linh; Medema, Marnix H; Raaijmakers, Jos M

    2017-11-01

    Pseudomonas fluorescens strain SS101 (Pf.SS101) promotes growth of Arabidopsis thaliana, enhances greening and lateral root formation, and induces systemic resistance (ISR) against the bacterial pathogen Pseudomonas syringae pv. tomato (Pst). Here, targeted and untargeted approaches were adopted to identify bacterial determinants and underlying mechanisms involved in plant growth promotion and ISR by Pf.SS101. Based on targeted analyses, no evidence was found for volatiles, lipopeptides and siderophores in plant growth promotion by Pf.SS101. Untargeted, genome-wide analyses of 7488 random transposon mutants of Pf.SS101 led to the identification of 21 mutants defective in both plant growth promotion and ISR. Many of these mutants, however, were auxotrophic and impaired in root colonization. Genetic analysis of three mutants followed by site-directed mutagenesis, genetic complementation and plant bioassays revealed the involvement of the phosphogluconate dehydratase gene edd, the response regulator gene colR and the adenylsulfate reductase gene cysH in both plant growth promotion and ISR. Subsequent comparative plant transcriptomics analyses strongly suggest that modulation of sulfur assimilation, auxin biosynthesis and transport, steroid biosynthesis and carbohydrate metabolism in Arabidopsis are key mechanisms linked to growth promotion and ISR by Pf.SS101. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  19. A novel psychrophilic lipase from Pseudomonas fluorescens with unique property in chiral resolution and biodiesel production via transesterification.

    Science.gov (United States)

    Luo, Yu; Zheng, Yitao; Jiang, Zhengbing; Ma, Yushu; Wei, Dongzhi

    2006-11-01

    A lipase-producing bacterium strain B68 screened from soil samples of China was identified as Pseudomonas fluorescens. With GenomeWalker, the open reading frame of lipase gene lipB68, encoding 476 amino acids, was cloned and expressed in Escherichia coli BL21 (DE3). By affinity chromatography, the recombinant LipB68 protein was purified to the purity of 95%. As a member of lipase subfamily I.3, LipB68 has a unique optimum temperature of 20 degrees C, which was the lowest in this subfamily. In chiral resolution, LipB68 effectively catalyzed the transesterification of both alpha-phenylethanol and alpha-phenylpropanol at 20 degrees C, achieving E values greater than 100 and 60 after 120 h, respectively. Among all the known catalysts in biodiesel production, LipB68 produced biodiesel with a yield of 92% after 12 h, at the lowest temperature of 20 degrees C, and is the first one of the I.3 lipase subfamily reported to be capable of catalyzing the transesterification reaction of biodiesel production. Since lipase-mediated biodiesel production is normally carried out at 35-50 degrees C, the availability of a highly active lipase with a low optimal temperature can provide substantial savings in energy consumption. Thus, this novel psychrophilic lipase (LipB68) may represent a highly competitive energy-saving biocatalyst.

  20. A novel psychrophilic lipase from Pseudomonas fluorescens with unique property in chiral resolution and biodiesel production via transesterification

    Energy Technology Data Exchange (ETDEWEB)

    Luo Yu; Zheng Yitao; Jiang Zhengbing; Ma Yushu; Wei Dongzhi [East China Univ. of Science and Tech., Shanghai (China). State Key Lab. of Bioreactor Engineering

    2006-11-15

    A lipase-producing bacterium strain B68 screened from soil samples of China was identified as Pseudomonas fluorescens. With GenomeWalker, the open reading frame of lipase gene lipB68, encoding 476 amino acids, was cloned and expressed in Escherichia coli BL21 (DE3). By affinity chromatography, the recombinant LipB68 protein was purified to the purity of 95%. As a member of lipase subfamily I.3, LipB68 has a unique optimum temperature of 20 C, which was the lowest in this subfamily. In chiral resolution, LipB68 effectively catalyzed the transesterification of both a-phenylethanol and a-phenylpropanol at 20 C, achieving E values greater than 100 and 60 after 120 h, respectively. Among all the known catalysts in biodiesel production, LipB68 produced biodiesel with a yield of 92% after 12 h, at the lowest temperature of 20 C, and is the first one of the I.3 lipase subfamily reported to be capable of catalyzing the transesterification reaction of biodiesel production. Since lipasemediated biodiesel production is normally carried out at 35-50 C, the availability of a highly active lipase with a low optimal temperature can provide substantial savings in energy consumption. Thus, this novel psychrophilic lipase (LipB68) may represent a highly competitive energy-saving biocatalyst. (orig.)

  1. Proteomic detection of non-annotated protein-coding genes in Pseudomonas fluorescens Pf0-1.

    Directory of Open Access Journals (Sweden)

    Wook Kim

    Full Text Available Genome sequences are annotated by computational prediction of coding sequences, followed by similarity searches such as BLAST, which provide a layer of possible functional information. While the existence of processes such as alternative splicing complicates matters for eukaryote genomes, the view of bacterial genomes as a linear series of closely spaced genes leads to the assumption that computational annotations that predict such arrangements completely describe the coding capacity of bacterial genomes. We undertook a proteomic study to identify proteins expressed by Pseudomonas fluorescens Pf0-1 from genes that were not predicted during the genome annotation. Mapping peptides to the Pf0-1 genome sequence identified sixteen non-annotated protein-coding regions, of which nine were antisense to predicted genes, six were intergenic, and one read in the same direction as an annotated gene but in a different frame. The expression of all but one of the newly discovered genes was verified by RT-PCR. Few clues as to the function of the new genes were gleaned from informatic analyses, but potential orthologs in other Pseudomonas genomes were identified for eight of the new genes. The 16 newly identified genes improve the quality of the Pf0-1 genome annotation, and the detection of antisense protein-coding genes indicates the under-appreciated complexity of bacterial genome organization.

  2. Genetic responses induced in olive roots upon colonization by the biocontrol endophytic bacterium Pseudomonas fluorescens PICF7.

    Directory of Open Access Journals (Sweden)

    Elisabetta Schilirò

    Full Text Available Knowledge on the genetic basis underlying interactions between beneficial bacteria and woody plants is still very limited, and totally absent in the case of olive. We aimed to elucidate genetic responses taking place during the colonization of olive roots by the native endophyte Pseudomonas fluorescens PICF7, an effective biocontrol agent against Verticillium wilt of olive. Roots of olive plants grown under non-gnotobiotic conditions were collected at different time points after PICF7 inoculation. A Suppression Subtractive Hybridization cDNA library enriched in induced genes was generated. Quantitative real time PCR (qRT-PCR analysis validated the induction of selected olive genes. Computational analysis of 445 olive ESTs showed that plant defence and response to different stresses represented nearly 45% of genes induced in PICF7-colonized olive roots. Moreover, quantitative real-time PCR (qRT-PCR analysis confirmed induction of lipoxygenase, phenylpropanoid, terpenoids and plant hormones biosynthesis transcripts. Different classes of transcription factors (i.e., bHLH, WRKYs, GRAS1 were also induced. This work highlights for the first time the ability of an endophytic Pseudomonas spp. strain to mount a wide array of defence responses in an economically-relevant woody crop such as olive, helping to explain its biocontrol activity.

  3. The role of a P1-type ATPase from Pseudomonas fluorescens SBW25 in copper homeostasis and plant colonization.

    Science.gov (United States)

    Zhang, Xue-Xian; Rainey, Paul B

    2007-05-01

    The genome of the plant-colonizing bacterium Pseudomonas fluorescens SBW25 possesses a putative copper-transporting P1-type ATPase (CueA) that is induced on the plant surfaces. Using a chromosomally-integrated cueA-lacZ fusion, we show that transcription of cueA can be induced (in vitro) by ions of copper, silver, gold, and mercury. To investigate the biological significance of cueA, a nonpolar cueA deletion mutant (SBW25 delta cueA) was constructed. This mutant strain displayed a twofold reduction in its tolerance to copper compared with the wild-type strain; however, no change was observed in the sensitivity of the mutant strain to silver, gold, or mercury ions. To obtain insight into the ecological significance of cueA, the competitive ability of SBW25 delta cueA was determined relative to wild-type SBW25 in three environments (none contained added copper): minimal M9 medium, the root of sugar beet (Beta vulgaris), and the root of pea (Pisum sativum). Results showed that the fitness of SBW25 delta cueA was not different from the wild type in laboratory medium but was compromised in the two plant environments. Taken together, these data demonstrate a functional role for CueA in copper homeostasis and reveal an ecologically significant contribution to bacterial fitness in the plant rhizosphere. They also suggest that copper ions accumulate on plant surfaces.

  4. Measurement of glucose utilization by Pseudomonas fluorescens that are free-living and that are attached to surfaces

    International Nuclear Information System (INIS)

    Fletcher, M.

    1986-01-01

    The assimilation and respiration of glucose by attached and free-living Pseudomonas fluorescens were compared. The attachment surfaces were polyvinylidene fluoride, polyethylene, and glass. Specific uptake of [ 1 C]glucose was determined after bacterial biomass was measured by (1) microscopic counts or (2) prelabelling of cells by providing [ 3 H]leucine as substrate, followed by dual-labelling scintillation counting. The glucose concentration was 1.4, 3.5, 5.5, 7.6, or 9.7 μM. Glucose assimilation by cells which became detached from the surfaces during incubation with glucose was also measured after the detached cells were collected by filtration. The composition of the substratum had no effect on the amount of glucose assimilated by attached cells. Glucose assimilation by attached cells exceeded that by free-living cells by a factor of between 2 and 5 or more, and respiration of glucose by surface-associated cells was greater than that by free-living bacteria. Glucose assimilation by detached cells was greater than that by attached bacteria. Measurements of biomass by microscopic counts gave more consistent results than those obtained with dual-labelling, but in general, results obtained by both methods were corroborative

  5. Pseudomonas fluorescens C7R12 type III secretion system impacts mycorrhization of Medicago truncatula and associated microbial communities.

    Science.gov (United States)

    Viollet, Amandine; Pivato, Barbara; Mougel, Christophe; Cleyet-Marel, Jean-Claude; Gubry-Rangin, Cécile; Lemanceau, Philippe; Mazurier, Sylvie

    2017-01-01

    Type three secretion systems (T3SSs) mediate cell-to-cell interactions between Gram-negative bacteria and eukaryotes. We hypothesized that fluorescent pseudomonads harboring T3SS (T3SS+) would be beneficial to arbuscular mycorrhizal symbiosis because non-pathogenic fluorescent pseudomonads have been previously shown to be much more abundant in mycorrhizal than in non-mycorrhizal roots. We tested this hypothesis by comparing mycorrhization and the associated rhizosphere microbial communities of Medicago truncatula grown in a non-sterile soil inoculated with either the T3SS+ mycorrhiza helper bacterium Pseudomonas fluorescens (C7R12) or a T3SS- mutant of the strain. Results showed that the bacterial secretion system was responsible for the promotion of mycorrhization because root colonization by arbuscular mycorrhizal fungi was not promoted by the T3SS- mutant. The observed T3SS-mediated promotion of mycorrhization was associated with changes in the rhizosphere bacterial communities and the increased occurrence of Claroidoglomeraceae within the intraradical arbuscular mycorrhizal fungi. Furthermore, both pseudomonad strains promoted the host-free growth of a model arbuscular mycorrhizal fungus in vitro, suggesting that T3SS-mediated promotion of mycorrhization occurs during plant-fungal interactions rather than during the pre-symbiotic phase of fungal growth. Taken together, these data provide evidence for the involvement of T3SS in promoting arbuscular mycorrhization by a model fluorescent pseudomonad and suggest the implication of interactions between the bacterium and mycorrhizas.

  6. Transcriptomic profiling of microbe-microbe interactions reveals the specific response of the biocontrol strain P. fluorescens In5 to the phytopathogen Rhizoctonia solani

    DEFF Research Database (Denmark)

    Hennessy, Rosanna Catherine; Glaring, Mikkel Andreas; Olsson, Stefan

    2017-01-01

    metabolites, e.g. non-ribosomal synthetases and hydrogen cyanide were not differentially expressed at the time points studied. CONCLUSION: This study demonstrates that genes possibly involved in metabolite detoxification are highly upregulated in P. fluorescens In5 when co-cultured with plant pathogens......BACKGROUND: Few studies to date report the transcriptional response of biocontrol bacteria toward phytopathogens. In order to gain insights into the potential mechanism underlying the antagonism of the antimicrobial producing strain P. fluorescens In5 against the phytopathogens Rhizoctonia solani....... fluorescens In5 or bacterial cultures in dual-culture for 48 h with each pathogen in biological triplicates. RNA-seq libraries were constructed following a default Illumina stranded RNA protocol including rRNA depletion and were sequenced 2 × 100 bases on Illumina HiSeq generating approximately 10 million...

  7. Adaptive Divergence in Experimental Populations of Pseudomonas fluorescens. V. Insight into the Niche Specialist Fuzzy Spreader Compels Revision of the Model Pseudomonas Radiation

    Science.gov (United States)

    Ferguson, Gayle C.; Bertels, Frederic; Rainey, Paul B.

    2013-01-01

    Pseudomonas fluorescens is a model for the study of adaptive radiation. When propagated in a spatially structured environment, the bacterium rapidly diversifies into a range of niche specialist genotypes. Here we present a genetic dissection and phenotypic characterization of the fuzzy spreader (FS) morphotype—a type that arises repeatedly during the course of the P. fluorescens radiation and appears to colonize the bottom of static broth microcosms. The causal mutation is located within gene fuzY (pflu0478)—the fourth gene of the five-gene fuzVWXYZ operon. fuzY encodes a β-glycosyltransferase that is predicted to modify lipopolysaccharide (LPS) O antigens. The effect of the mutation is to cause cell flocculation. Analysis of 92 independent FS genotypes showed each to have arisen as the result of a loss-of-function mutation in fuzY, although different mutations have subtly different phenotypic and fitness effects. Mutations within fuzY were previously shown to suppress the phenotype of mat-forming wrinkly spreader (WS) types. This prompted a reinvestigation of FS niche preference. Time-lapse photography showed that FS colonizes the meniscus of broth microcosms, forming cellular rafts that, being too flimsy to form a mat, collapse to the vial bottom and then repeatably reform only to collapse. This led to a reassessment of the ecology of the P. fluorescens radiation. Finally, we show that ecological interactions between the three dominant emergent types (smooth, WS, and FS), combined with the interdependence of FS and WS on fuzY, can, at least in part, underpin an evolutionary arms race with bacteriophage SBW25Φ2, to which mutation in fuzY confers resistance. PMID:24077305

  8. Identification of Amino Acid Residues Responsible for the Enantioselectivity and Amide Formation Capacity of the Arylacetonitrilase from Pseudomonas fluorescens EBC191 ▿ †

    Science.gov (United States)

    Kiziak, Christoph; Stolz, Andreas

    2009-01-01

    The nitrilase from Pseudomonas fluorescens EBC191 converted (R,S)-mandelonitrile with a low enantioselectivity to (R)-mandelic acid and (S)-mandeloamide in a ratio of about 4:1. In contrast, the same substrate was hydrolyzed by the homologous nitrilase from Alcaligenes faecalis ATCC 8750 almost exclusively to (R)-mandelic acid. A chimeric enzyme between both nitrilases was constructed, which represented in total 16 amino acid exchanges in the central part of the nitrilase from P. fluorescens EBC191. The chimeric enzyme clearly resembled the nitrilase from A. faecalis ATCC 8750 in its turnover characteristics for (R,S)-mandelonitrile and (R,S)-2-phenylpropionitrile (2-PPN) and demonstrated an even higher enantioselectivity for the formation of (R)-mandelic acid than the nitrilase from A. faecalis. An alanine residue (Ala165) in direct proximity to the catalytically active cysteine residue was replaced in the nitrilase from P. fluorescens by a tryptophan residue (as found in the nitrilase from A. faecalis ATCC 8750 and most other bacterial nitrilases) and several other amino acid residues. Those enzyme variants that possessed a larger substituent in position 165 (tryptophan, phenylalanine, tyrosine, or histidine) converted racemic mandelonitrile and 2-PPN to increased amounts of the R enantiomers of the corresponding acids. The enzyme variant Ala165His showed a significantly increased relative activity for mandelonitrile (compared to 2-PPN), and the opposite was found for the enzyme variants carrying aromatic residues in the relevant position. The mutant forms carrying an aromatic substituent in position 165 generally formed significantly reduced amounts of mandeloamide from mandelonitrile. The important effect of the corresponding amino acid residue on the reaction specificity and enantiospecificity of arylacetonitrilases was confirmed by the construction of a Trp164Ala variant of the nitrilase from A. faecalis ATCC 8750. This point mutation converted the highly R

  9. Efeito da pré-incubação de Pseudomonas fluorescens em diferentes temperaturas de refrigeração sobre a hidrólise de caseína no leite desnatado pasteurizado microfiltrado

    OpenAIRE

    Netto, Gabriel Gama

    2012-01-01

    Este trabalho objetivou avaliar o efeito da multiplicação de uma estirpe psicrotrófica proteolítica de Pseudomonas fluorescens nas temperaturas de 4, 7 e 10 ºC, estabelecidas pela Instrução Normativa 62 do MAPA, nas características físicoquímicas e proteólise do leite microfiltrado. Amostras leite desnatado e pasteurizado foram inoculadas com a cepa Pseudomonas fluorescens 041 em uma concentração de aproximadamente 104 UFC mL-1 e incubadas nas três temperaturas por 48 h e, posteriormente, ...

  10. Proteomic analysis of elicitation of downy mildew disease resistance in pearl millet by seed priming with β-aminobutyric acid and Pseudomonas fluorescens.

    Science.gov (United States)

    Anup, Chandra Pal; Melvin, Prasad; Shilpa, Nataraj; Gandhi, Mayuri Nalin; Jadhav, Manali; Ali, Hussain; Kini, Kukkundoor Ramachandra

    2015-04-29

    Downy mildew is one of the severe diseases of pearl millet, globally affecting its commercial production. Priming of seeds of a susceptible cultivar of pearl millet with β-aminobutyric acid (BABA) and Pseudomonas fluorescens has reduced the downy mildew disease incidence level under field studies. In the current study, proteomic approach was used to elucidate the poorly studied resistance mechanism in these elicitor primed pearl millet seeds in response to Sclerospora graminicola infection. 2DE-MS/MS based proteomic approach revealed that majority of the 63 differentially accumulated (p≤0.05) proteins associated with energy and metabolism followed by stress and defense category. Multivariate statistics disclosed that infection caused by the pathogen rather than elicitor treatment had a major influence on the dynamics of protein abundance. Mechanism of priming mediated by BABA and P. fluorescens were different from each other as evident by the protein abundance profile of hierarchical clustering analysis. Over-representation of proteins pertaining to glucose metabolism suggests that seed priming ensures plant protection against disease without compromising its normal growth and development. In addition the study forms a basis for future investigation by functional analysis of these differentially accumulated proteins to further unravel the resistance mechanism of elicitor primed plant against the S. graminicola. The study is based on the comparative proteomic analysis between BABA and P. fluorescens mediated resistance in pearl millet, in response to downy mildew causing biotroph - S. graminicola. To our knowledge, this article is the first to report on seedling proteome of pearl millet whose genome is not yet sequenced. In addition, the study also provides clue for the plausible antagonistic cross-talk that might exist between jasmonic acid signaling and salicylic acid signaling in SAR and ISR mediated resistance by BABA and P. fluorescens against the downy

  11. Safety of spray-dried powder formulated Pseudomonas fluorescens strain CL145A exposure to subadult/adult unionid mussels during simulated open-water treatments

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Waller, Diane L.; Wise, Jeremy K.; Mayer, Denise A.; Aloisi, Douglas B.

    2015-01-01

    The exposure effects of a commercially prepared spray dried powder (SDP) formulation ofPseudomonas fluorescens (strain CL145A) on the survival of seven species of unionid mussels endemic to the Great Lakes and Mississippi River basins was evaluated in this study. The study exposures were completed within replicated 350-liter test tanks contained within a mobile bioassay laboratory sited on the shores of the Black River near La Crosse, Wisconsin. The test tanks were supplied with flowing, filtered river water which was interrupted during the exposure period.

  12. PENGARUH APLIKASI PSEUDOMONAS FLUORESCENS P60 TERHADAP MUTU PATOLOGIS, MUTU FISIOLOGIS, DAN PERTUMBUHAN BIBIT PADI IR 64

    Directory of Open Access Journals (Sweden)

    Lisa Navitasari

    2014-08-01

    Full Text Available Effect of Pseudomonas fluorescens P60 on pathological and physiological quality and growth of rice IR 64  seedlings. The research objectives were (1 detection and identification of seed-borne pathogens of IR 64 rice, (2 testing Pseudomonas fluorescents P60 in inhibiting the in vitro growth of seed-borne pathogens colonies, (3 testing P. fluorescents P60 for pathological and physiological seed quality, and (4 testing P. fluorescents P60 on the growth of seedlings in the greenhouse. The results showed that some seed-borne pathogens can be found both on farmers’ IR 64 rice and factory’s; they were Aspergillus flavus, Alternaria padwickii, Pseudomonas glumae, and P. syringae. Application of P. flourescens P60 was able to inhibit the in vitrogrowth of colonies of all seed-borne pathogens, except P. syringae.  Related to pathological quality, the effect of P. flourescens P60 on percentage of seed-borne pathogens attack did not significantly different from that of benomil but smaller than distilled water. On the physiological quality of seeds, treatment of P. flourescens P60 has the same effect with benomil and distilled water, with  germination rate was more than 80%. In the greenhouse study,treatment of seed immersion time  in P. flourescens P60 suspension showed that the effect of immersion time as long as15 minutes and 25 minutes on  seedling height, root length, and seedling dry weightdid not significantly different. were. However, 25 minutes immersion time resulted in fresh seedling weight and root dry weight higher than that of 15 minutes immersion time.

  13. Metabolic and Transcriptomic Changes Induced in Arabidopsis by the Rhizobacterium Pseudomonas fluorescens SS1011[W][OA

    Science.gov (United States)

    van de Mortel, Judith E.; de Vos, Ric C.H.; Dekkers, Ester; Pineda, Ana; Guillod, Leandre; Bouwmeester, Klaas; van Loon, Joop J.A.; Dicke, Marcel; Raaijmakers, Jos M.

    2012-01-01

    Systemic resistance induced in plants by nonpathogenic rhizobacteria is typically effective against multiple pathogens. Here, we show that root-colonizing Pseudomonas fluorescens strain SS101 (Pf.SS101) enhanced resistance in Arabidopsis (Arabidopsis thaliana) against several bacterial pathogens, including Pseudomonas syringae pv tomato (Pst) and the insect pest Spodoptera exigua. Transcriptomic analysis and bioassays with specific Arabidopsis mutants revealed that, unlike many other rhizobacteria, the Pf.SS101-induced resistance response to Pst is dependent on salicylic acid signaling and not on jasmonic acid and ethylene signaling. Genome-wide transcriptomic and untargeted metabolomic analyses showed that in roots and leaves of Arabidopsis plants treated with Pf.SS101, approximately 1,910 genes and 50 metabolites were differentially regulated relative to untreated plants. Integration of both sets of “omics” data pointed to a prominent role of camalexin and glucosinolates in the Pf.SS101-induced resistance response. Subsequent bioassays with seven Arabidopsis mutants (myb51, cyp79B2cyp79B3, cyp81F2, pen2, cyp71A12, cyp71A13, and myb28myb29) disrupted in the biosynthesis pathways for these plant secondary metabolites showed that camalexin and glucosinolates are indeed required for the induction of Pst resistance by Pf.SS101. Also for the insect S. exigua, the indolic glucosinolates appeared to play a role in the Pf.SS101-induced resistance response. This study provides, to our knowledge for the first time, insight into the substantial biochemical and temporal transcriptional changes in Arabidopsis associated with the salicylic acid-dependent resistance response induced by specific rhizobacteria. PMID:23073694

  14. Pseudomonas fluorescens F113 Mutant with Enhanced Competitive Colonization Ability and Improved Biocontrol Activity against Fungal Root Pathogens ▿

    Science.gov (United States)

    Barahona, Emma; Navazo, Ana; Martínez-Granero, Francisco; Zea-Bonilla, Teresa; Pérez-Jiménez, Rosa María; Martín, Marta; Rivilla, Rafael

    2011-01-01

    Motility is one of the most important traits for efficient rhizosphere colonization by Pseudomonas fluorescens F113rif (F113). In this bacterium, motility is a polygenic trait that is repressed by at least three independent pathways, including the Gac posttranscriptional system, the Wsp chemotaxis-like pathway, and the SadB pathway. Here we show that the kinB gene, which encodes a signal transduction protein that together with AlgB has been implicated in alginate production, participates in swimming motility repression through the Gac pathway, acting downstream of the GacAS two-component system. Gac mutants are impaired in secondary metabolite production and are unsuitable as biocontrol agents. However, the kinB mutant and a triple mutant affected in kinB, sadB, and wspR (KSW) possess a wild-type phenotype for secondary metabolism. The KSW strain is hypermotile and more competitive for rhizosphere colonization than the wild-type strain. We have compared the biocontrol activity of KSW with those of the wild-type strain and a phenotypic variant (F113v35 [V35]) which is hypermotile and hypercompetitive but is affected in secondary metabolism since it harbors a gacS mutation. Biocontrol experiments in the Fusarium oxysporum f. sp. radicis-lycopersici/Lycopersicum esculentum (tomato) and Phytophthora cactorum/Fragaria vesca (strawberry) pathosystems have shown that the three strains possess biocontrol activity. Biocontrol activity was consistently lower for V35, indicating that the production of secondary metabolites was the most important trait for biocontrol. Strain KSW showed improved biocontrol compared with the wild-type strain, indicating that an increase in competitive colonization ability resulted in improved biocontrol and that the rational design of biocontrol agents by mutation is feasible. PMID:21685161

  15. Pseudomonas fluorescens F113 mutant with enhanced competitive colonization ability and improved biocontrol activity against fungal root pathogens.

    Science.gov (United States)

    Barahona, Emma; Navazo, Ana; Martínez-Granero, Francisco; Zea-Bonilla, Teresa; Pérez-Jiménez, Rosa María; Martín, Marta; Rivilla, Rafael

    2011-08-01

    Motility is one of the most important traits for efficient rhizosphere colonization by Pseudomonas fluorescens F113rif (F113). In this bacterium, motility is a polygenic trait that is repressed by at least three independent pathways, including the Gac posttranscriptional system, the Wsp chemotaxis-like pathway, and the SadB pathway. Here we show that the kinB gene, which encodes a signal transduction protein that together with AlgB has been implicated in alginate production, participates in swimming motility repression through the Gac pathway, acting downstream of the GacAS two-component system. Gac mutants are impaired in secondary metabolite production and are unsuitable as biocontrol agents. However, the kinB mutant and a triple mutant affected in kinB, sadB, and wspR (KSW) possess a wild-type phenotype for secondary metabolism. The KSW strain is hypermotile and more competitive for rhizosphere colonization than the wild-type strain. We have compared the biocontrol activity of KSW with those of the wild-type strain and a phenotypic variant (F113v35 [V35]) which is hypermotile and hypercompetitive but is affected in secondary metabolism since it harbors a gacS mutation. Biocontrol experiments in the Fusarium oxysporum f. sp. radicis-lycopersici/Lycopersicum esculentum (tomato) and Phytophthora cactorum/Fragaria vesca (strawberry) pathosystems have shown that the three strains possess biocontrol activity. Biocontrol activity was consistently lower for V35, indicating that the production of secondary metabolites was the most important trait for biocontrol. Strain KSW showed improved biocontrol compared with the wild-type strain, indicating that an increase in competitive colonization ability resulted in improved biocontrol and that the rational design of biocontrol agents by mutation is feasible.

  16. The biocontrol endophytic bacterium Pseudomonas fluorescens PICF7 induces systemic defense responses in aerial tissues upon colonization of olive roots

    Directory of Open Access Journals (Sweden)

    Carmen eGómez-Lama Cabanás

    2014-09-01

    Full Text Available Pseudomonas fluorescens PICF7, a native olive root endophyte and effective biocontrol agent (BCA against Verticillium wilt of olive, is able to trigger a broad range of defense responses in root tissues of this woody plant. In order to elucidate whether strain PICF7 also induces systemic defense responses in above-ground organs, aerial tissues of olive plants grown under non-gnotobiotic conditions were collected at different time points after root bacterization with this endophytic BCA. A suppression subtractive hybridization (SSH cDNA library, enriched in up-regulated genes, was generated. This strategy enabled the identification of 376 ESTs (99 contigs and 277 singlets, many of them related to response to different stresses. Five ESTs, involved in defense responses, were selected to carry out time-course quantitative real-time PCR (qRT-PCR experiments aiming to: (i validate the induction of these genes, and (ii shed light on their expression pattern along time (from 1 to 15 days. Induction of olive genes potentially coding for lypoxigenase 2, catalase, 1-aminocyclopropane-1-carboxylate oxidase and phenylananine ammonia-lyase was thus confirmed at some time points. Computational analysis also revealed that different transcription factors were up-regulated in olive aerial tissues (i.e. jerf, bHLH, WRKYs, as previously reported for roots. Results confirmed that root colonization by this endophytic bacterium does not only trigger defense responses in this organ but also mount a wide array of systemic defense responses in distant tissues (stems, leaves. This sheds light on how olive plants respond to the ‘non-hostile’ colonization by a bacterial endophyte and how induced defense response can contribute to the biocontrol activity of strain PICF7.

  17. Accumulation of α-Keto Acids as Essential Components in Cyanide Assimilation by Pseudomonas fluorescens NCIMB 11764

    Science.gov (United States)

    Kunz, Daniel A.; Chen, Jui-Lin; Pan, Guangliang

    1998-01-01

    Pyruvate (Pyr) and α-ketoglutarate (αKg) accumulated when cells of Pseudomonas fluorescens NCIMB 11764 were cultivated on growth-limiting amounts of ammonia or cyanide and were shown to be responsible for the nonenzymatic removal of cyanide from culture fluids as previously reported (J.-L. Chen and D. A. Kunz, FEMS Microbiol. Lett. 156:61–67, 1997). The accumulation of keto acids in the medium paralleled the increase in cyanide-removing activity, with maximal activity (760 μmol of cyanide removed min−1 ml of culture fluid−1) being recovered after 72 h of cultivation, at which time the keto acid concentration was 23 mM. The reaction products that formed between the biologically formed keto acids and cyanide were unambiguously identified as the corresponding cyanohydrins by 13C nuclear magnetic resonance spectroscopy. Both the Pyr and α-Kg cyanohydrins were further metabolized by cell extracts and served also as nitrogenous growth substrates. Radiotracer experiments showed that CO2 (and NH3) were formed as enzymatic conversion products, with the keto acid being regenerated as a coproduct. Evidence that the enzyme responsible for cyanohydrin conversion is cyanide oxygenase, which was shown previously to be required for cyanide utilization, is based on results showing that (i) conversion occurred only when extracts were induced for the enzyme, (ii) conversion was oxygen and reduced-pyridine nucleotide dependent, and (iii) a mutant strain defective in the enzyme was unable to grow when it was provided with the cyanohydrins as a growth substrate. Pyr and αKg were further shown to protect cells from cyanide poisoning, and excretion of the two was directly linked to utilization of cyanide as a growth substrate. The results provide the basis for a new mechanism of cyanide detoxification and assimilation in which keto acids play an essential role. PMID:9797306

  18. The biocontrol endophytic bacterium Pseudomonas fluorescens PICF7 induces systemic defense responses in aerial tissues upon colonization of olive roots.

    Science.gov (United States)

    Gómez-Lama Cabanás, Carmen; Schilirò, Elisabetta; Valverde-Corredor, Antonio; Mercado-Blanco, Jesús

    2014-01-01

    Pseudomonas fluorescens PICF7, a native olive root endophyte and effective biocontrol agent (BCA) against Verticillium wilt of olive, is able to trigger a broad range of defense responses in root tissues of this woody plant. In order to elucidate whether strain PICF7 also induces systemic defense responses in above-ground organs, aerial tissues of olive plants grown under non-gnotobiotic conditions were collected at different time points after root bacterization with this endophytic BCA. A suppression subtractive hybridization (SSH) cDNA library, enriched in up-regulated genes, was generated. This strategy enabled the identification of 376 ESTs (99 contigs and 277 singlets), many of them related to response to different stresses. Five ESTs, involved in defense responses, were selected to carry out time-course quantitative real-time PCR (qRT-PCR) experiments aiming to: (1) validate the induction of these genes, and (2) shed light on their expression pattern along time (from 1 to 15 days). Induction of olive genes potentially coding for lipoxygenase 2, catalase, 1-aminocyclopropane-1-carboxylate oxidase, and phenylananine ammonia-lyase was thus confirmed at some time points. Computational analysis also revealed that different transcription factors were up-regulated in olive aerial tissues (i.e., JERF, bHLH, WRKY), as previously reported for roots. Results confirmed that root colonization by this endophytic bacterium does not only trigger defense responses in this organ but also mounts a wide array of systemic defense responses in distant tissues (stems, leaves). This sheds light on how olive plants respond to the "non-hostile" colonization by a bacterial endophyte and how induced defense response can contribute to the biocontrol activity of strain PICF7.

  19. Factors screening to statistical experimental design of racemic atenolol kinetic resolution via transesterification reaction in organic solvent using free Pseudomonas fluorescens lipase.

    Science.gov (United States)

    Agustian, Joni; Kamaruddin, Azlina Harun; Aboul-Enein, Hassan Y

    2017-07-01

    As the (R)-enantiomer of racemic atenolol has no β-blocking activity and no lack of side effects, switching from the racemate to the (S)-atenolol is more favorable. Transesterification of racemic atenolol using free enzymes investigated as a resource to resolve the racemate via this method is limited. Screenings of enzyme, medium, and acetyl donor were conducted first to give Pseudomonas fluorescens lipase, tetrahydrofuran, and vinyl acetate. A statistical design of the experiment was then developed using Central Composite Design on some operational factors, which resulted in the conversions of 11.70-61.91% and substrate enantiomeric excess (ee) of 7.31-100%. The quadratic models are acceptable with R 2 of 95.13% (conversion) and 89.63% (ee). The predicted values match the observed values reasonably well. Temperature, agitation speed, and substrate molar ratio factor have low effects on conversion and ee, but enzyme loading affects the responses highly. The interaction of temperature-agitation speed and temperature-substrate molar ratio show significant effects on conversion, while temperature-agitation speed, temperature-substrate molar ratio, and agitation speed-substrate molar ratio affect ee highly. Optimum conditions for the use of Pseudomonas fluorescens lipase, tetrahydrofuran, and vinyl acetate were found at 45°C, 175 rpm, 2000 U, and 1:3.6 substrate molar ratio. © 2017 Wiley Periodicals, Inc.

  20. Genomic analysis of the biocontrol strain Pseudomonas fluorescens Pf29Arp with evidence of T3SS and T6SS gene expression on plant roots.

    Science.gov (United States)

    Marchi, Muriel; Boutin, Morgane; Gazengel, Kévin; Rispe, Claude; Gauthier, Jean-Pierre; Guillerm-Erckelboudt, Anne-Yvonne; Lebreton, Lionel; Barret, Matthieu; Daval, Stéphanie; Sarniguet, Alain

    2013-06-01

    Several bacterial strains of the Pseudomonas genus provide plant growth stimulation, plant protection against pests or bioremediation. Among these bacteria, P. fluorescens Pf29Arp reduces the severity of take-all, a disease caused by the pathogenic fungus Gaeumannomyces graminis var. tritici (Ggt) on wheat roots. In this study, we obtained a draft genome of Pf29Arp and subsequent comparative genomic analyses have revealed that this bacterial strain is closely related to strains of the 'P. brassicacearum-like' subgroup including P. brassicacearum ssp. brassicacearum NFM421 and P. fluorescens F113. Despite an overall chromosomal organization similar to these strains, a number of features including antibiotic synthesis gene clusters from secondary metabolism are not found in the Pf29Arp genome. But Pf29Arp possesses different protein secretion systems including type III (T3SS) and type VI (T6SS) secretion systems. Pf29Arp is the first Pseudomonas sp. strain described with four T6SS clusters (cluster I, II, III and IV). In addition, some protein-coding genes involved in the assembly of these secretion systems are basally expressed during Pf29Arp colonization of healthy wheat roots and display different expression patterns on necrotized roots caused by Ggt. These data suggest a role of T3SS and T6SS in the Pf29Arp adaptation to different root environments. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

  1. Influence of Arbuscular Mycorrhizal Fungi and Pseudomonas fluorescens at Different Superphosphate Levels on Linseed (Linum usitatissimum L. Growth Response Influencia de Hongos Micorriza Arbusculares y Pseudomonas fluorescens con Diferentes Niveles de Superfosfato sobre la Respuesta al Crecimiento de Lino (Linum usitatissimum L.

    Directory of Open Access Journals (Sweden)

    Neetu Neetu

    2012-06-01

    Full Text Available The aim of this study was to investigate the influence of arbuscular mycorrhizal fungi (AMF Glomus mosseae (T.H. Nicolson & Gerd. Gerd. & Trappe and Acaulospora laevis (Gerd. & Trappe on linseed (Linum usitatissimum L. growth response with phosphate solubilizing bacteria Pseudomonas fluorescens; different doses of superphosphate were used: 20 kg ha4 (half recommended dose, 40 kg ha4 (recommended dose, and 80 kg ha4 (double recommended dose in earthen pots filled with sterilized soil under greenhouse conditions. Among all the growth parameters, the following were the highest in the G. mosseae + P. fluorescens combination at the medium concentration (recommended superphosphate dose: plant height (78.74 ± 1.8 cm, fresh shoot weight (3.45 ± 0.294 g, dry shoot weight (0.57 ± 0.007 g, fresh root weight (0.223 ± 0.023 g, dry root weight (0.036 ± 0.004 g, root length (17.67 ± 0.48 cm, AM spore number (94.4 ± 9.86, shoot (1.14 ± 0.115% and root (1.29 ± 0.110% P content, and acidic (0.447 ± 0.012 IU g-1 FW and alkaline phosphatase activity (0.119 ± 0.008 IU g-1 FW. The percentage mycorrhizal root colonization with the A. laevis + P. fluorescens (86.86 ± 2.17% combination and chlorophyll content with the G. mosseae + A. laevis + P. fluorescens (0.474 ± 0.009 mg g-1 FW combination recorded the highest values at the low concentration (half recommended superphosphate dose as compared with non-mycorrhizal plants (control. The high superphosphate dose clearly reduced or decreased all the growth parameters. Therefore, vigorous growth and maximum flax yield can be achieved by inoculating plants with AM fungi and P. fluorescens with the recommended dose or less than the recommended dose of superphosphate.La presente investigation tuvo como objetivo estudiar la influencia de hongos micorrícicos arbusculares (AMF, i.e., Glomus mosseae (T.H. Nicolson & Gerd. Gerd. & Trappey Acaulospora laevis (Gerd. & Trappe, en la respuesta de crecimiento de lino

  2. Isolated galaxies

    International Nuclear Information System (INIS)

    Einasto, Maret

    1990-01-01

    To test for the possible presence of really isolated galaxies, which form a randomly distributed population in voids, we compare the distribution of most isolated galaxies in an observed sample with distributions of the same number of random points using the nearest neighbour test. The results show that the random population of really isolated galaxies does not exist - even the most isolated galaxies are connected with systems of galaxies, forming their outlying parts. (author)

  3. Development and validation of a real-time TaqMan assay for the detection and enumeration of Pseudomonas fluorescens ATCC 13525 used as a challenge organism in testing of food equipments.

    Science.gov (United States)

    Saha, Ratul; Bestervelt, Lorelle L; Donofrio, Robert S

    2012-02-01

    Pseudomonas fluorescens ATCC 13525 is used as the challenge organism to evaluate the efficacy of the clean-in-place (CIP) process of food equipment (automatic ice-maker) as per NSF/ANSI Standard 12. Traditional culturing methodology is presently used to determine the concentration of the challenge organism, which takes 48 h to confirm the cell density. Storage of the challenge preparation in the refrigerator might alter the cell density as P. fluorescens is capable of growing at 4 °C. Also, background organism can grow on the Pseudomonas F agar (PFA) used for the recovery of P. fluorescens thus affecting the results of the test. Real-time TaqMan assay targeting the cpn60 gene was developed for the enumeration and the identification of P. fluorescens because of its specificity, accuracy, and shorter turnaround time. The TaqMan primer-probe pair developed using the Allele ID® 7.0 probe design software was highly specific and sensitive for the target organism. The sensitivity of the assay was 10 colony forming units (CFU)/mL. The assay was also successful in determining the concentration of the challenge preparation within 2 h. Based on these observations, TaqMan assay targeting the cpn60 gene can be efficiently used for strain level identification and enumeration of bacteria. Pseudomonas fluorescens ATCC 13525 is used as a challenge organism in the efficacy testing of clean-in-place process of food equipments. Currently, culturing technique is used for its identification and estimation, which is not only time-consuming but also prone to error. Real-time TaqMan assay is more specific, sensitive, and accurate along with a shorter turnaround time compared to culturing techniques, thereby increasing the overall quality of the testing methodology to evaluate the clean-in-place process critical for the food industry to protect public health and safety. © 2012 Institute of Food Technologists®

  4. Activity screening of plant growth promoting rhizobacteria isolated from alfalfa rhizosphere

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    shahla pashapour

    2016-03-01

    Full Text Available Introduction: Some rhizobacteria by various mechanisms influence plant growth as they are called plant growth promoting rhizobacteria (PGPR. Scientists identified some PGPR characters involved in promoting plant growth, while all these characters are not able to study. The aim of this study was to evaluate PGP activities of bacterial isolates, (45 isolates belonged to rhizobium and 2 bacterial isolates belonged to Pseudomonas fluorescens, which were isolated from alfalfa (Medicago sativa rhizosphere and root nodules grown around Zanjan. Materials and methods: These bacteria were isolated from alfalfa roots grown around Zinc industries in Zanjan province. After bacterial isolation and purification from root and soil samples, isolates were screened in vitro for plant growth promoting traits such as IAA (Indole Acetic Acid, ACC- deaminase (Amino Cyclopropan Carboxylate, HCN (Hydrogen Cyanide, siderophore, chitinase production and mineral and organic phosphate solubilization activities. Results: The results indicated that 43 bacterial isolates produced IAA (4.04- 4.95 μg/ml and 15 isolates produced ACC- deaminase (0.23- 1.05 μg/ml. Only one isolate (Rm66 produced high amount of HCN. Qualitative siderophore production was observed in 9 isolates. None of the isolates produced chitinase. Solubilization of mineral phosphate was commonly detected in 19 isolates (4.33- 5.86 μg/ml, and 15 isolates solubilized organic phosphate (1.66- 144.28 μg/ml. Discussion and conclusion: This study shows that most of the bacterial strains which isolated from alfalfa cultivated lands had PGP activities and also a good potential to increase plant growth after inoculation with to seeds as eco- friendly fertilizers.

  5. Application of Endophytic Pseudomonas fluorescens and a Bacterial Consortium to Brassica napus Can Increase Plant Height and Biomass under Greenhouse and Field Conditions

    Directory of Open Access Journals (Sweden)

    Richard D. Lally

    2017-12-01

    Full Text Available Plant associated bacteria with plant growth promotion (PGP properties have been proposed for use as environmentally friendly biofertilizers for sustainable agriculture; however, analysis of their efficacy in the field is often limited. In this study, greenhouse and field trials were carried out using individual endophytic Pseudomonas fluorescens strains, the well characterized rhizospheric P. fluorescens F113 and an endophytic microbial consortium of 10 different strains. These bacteria had been previously characterized with respect to their PGP properties in vitro and had been shown to harbor a range of traits associated with PGP including siderophore production, 1-aminocyclopropane-1-carboxylic acid (ACC deaminase activity, and inorganic phosphate solubilization. In greenhouse experiments individual strains tagged with gfp and Kmr were applied to Brassica napus as a seed coat and were shown to effectively colonize the rhizosphere and root of B. napus and in addition they demonstrated a significant increase in plant biomass compared with the non-inoculated control. In the field experiment, the bacteria (individual and consortium were spray inoculated to winter oilseed rape B. napus var. Compass which was grown under standard North Western European agronomic conditions. Analysis of the data provides evidence that the application of the live bacterial biofertilizers can enhance aspects of crop development in B. napus at field scale. The field data demonstrated statistically significant increases in crop height, stem/leaf, and pod biomass, particularly, in the case of the consortium inoculated treatment. However, although seed and oil yield were increased in the field in response to inoculation, these data were not statistically significant under the experimental conditions tested. Future field trials will investigate the effectiveness of the inoculants under different agronomic conditions.

  6. Investigation of zoonotic disease pathogens (Aeromonas hydrophila, Pseudomonas fluorescens, Streptococcus iniae) seen in carp farms in the Northern Iraq-Erbil region by molecular methods

    Science.gov (United States)

    Ibraheem, Azad Saber; Önalan, Şükrü; Arabacı, Muhammed

    2017-04-01

    The aim of this study was to determine the zoonotic bacteria in carp farms in the Northern Iraq-Erbil region. Carp is the main fish species cultured in Erbil region. The most common zoonotic bacteria generally seen in carp farms are Aeromonas hydrophila, Pseudomonas fluorescens and Streptococcus iniae. Samples were collected from 25 carp farms in the Northern Iraq-Erbil region. Six carp samples were collected from each carp farm. Head kidney and intestine tissue samples were collected from each carp sample. Then head kidney and intestine tissue samples were pooled separately from each carp farm. Total bacterial DNA had been extracted from the 25 pooled head kidney and 25 intestinal tissue samples. The pathogen Primers were originally designed from 16S RNA gene region. Zoonotic bacteria were scanned in all tissue samples with absent/present analysis by RT-PCR. Furthermore, the capillary gel electrophoresis bands were used for confirmation of amplicon size which was planned during primer designing stage. As a result, thirteen carp farms were positive in the respect to Aeromonas hydrophila, eight carp farms were positive from head kidney and six carp farms were positive from the intestine, only one carp farm was positive from both head kidney and the intestine tissue samples. In the respect to Streptococcus iniae, four carp farms were positive from head kidney and two carp farms were positive from the intestine. Only one carp farm was positive in the respect to Pseudomonas fluorescens from the intestine. Totally, 9 of 25 carp farms were cleared (negative) the zoonotic bacteria. In conclusion, the zoonotic bacteria were high (64 %) in carp farms in the Northern Iraq-Erbil region.

  7. Endophytic Bacterium Pseudomonas fluorescens RG11 May Transform Tryptophan to Melatonin and Promote Endogenous Melatonin Levels in the Roots of Four Grape Cultivars.

    Science.gov (United States)

    Ma, Yaner; Jiao, Jian; Fan, Xiucai; Sun, Haisheng; Zhang, Ying; Jiang, Jianfu; Liu, Chonghuai

    2016-01-01

    Endophytes have been verified to synthesize melatonin in vitro and promote abiotic stress-induced production of endogenous melatonin in grape ( Vitis vinifera L.) roots. This study aimed to further characterize the biotransformation of tryptophan to melatonin in the endophytic bacterium Pseudomonas fluorescens RG11 and to investigate its capacity for enhancing endogenous melatonin levels in the roots of different grape cultivars. Using ultra performance liquid chromatography-tandem mass spectrometry combined with 15N double-labeled L -tryptophan as the precursor for melatonin, we detected isotope-labeled 5-hydroxytryptophan, serotonin, N -acetylserotonin, and melatonin, but tryptamine was not detected during the in vitro incubation of P. fluorescens RG11. Furthermore, the production capacity of these four compounds peaked during the exponential growth phase. RG11 colonization increased the endogenous levels of 5-hydroxytryptophan, N -acetylserotonin, and melatonin, but reduced those of tryptamine and serotonin, in the roots of the Red Globe grape cultivar under salt stress conditions. Quantitative real-time PCR revealed that RG11 reduced the transcription of grapevine tryptophan decarboxylase and serotonin N -acetyltransferase genes when compared to the un-inoculated control. These results correlated with decreased reactive oxygen species bursts and cell damage, which were alleviated by RG11 colonization under salt stress conditions. Additionally, RG11 promoted plant growth and enhanced the levels of endogenous melatonin in different grape cultivars. Intraspecific variation in the levels of melatonin precursors was found among four grape cultivars, and the associated root crude extracts appeared to significantly induce RG11 melatonin biosynthesis in vitro . Overall, this study provides useful information that enhances the existing knowledge of a potential melatonin synthesis pathway in rhizobacteria, and it reveals plant-rhizobacterium interactions that affect

  8. The periplasmic transaminase PtaA of Pseudomonas fluorescens converts the glutamic acid residue at the pyoverdine fluorophore to α-ketoglutaric acid.

    Science.gov (United States)

    Ringel, Michael T; Dräger, Gerald; Brüser, Thomas

    2017-11-10

    The periplasmic conversion of ferribactin to pyoverdine is essential for siderophore biogenesis in fluorescent pseudomonads, such as pathogenic Pseudomonas aeruginosa or plant growth-promoting Pseudomonas fluorescens The non-ribosomal peptide ferribactin undergoes cyclizations and oxidations that result in the fluorophore, and a strictly conserved fluorophore-bound glutamic acid residue is converted to a range of variants, including succinamide, succinic acid, and α-ketoglutaric acid residues. We recently discovered that the pyridoxal phosphate-containing enzyme PvdN is responsible for the generation of the succinamide, which can be hydrolyzed to succinic acid. Based on this, a distinct unknown enzyme was postulated to be responsible for the conversion of the glutamic acid to α-ketoglutaric acid. Here we report the identification and characterization of this enzyme in P. fluorescens strain A506. In silico analyses indicated a periplasmic transaminase in fluorescent pseudomonads and other proteobacteria that we termed PtaA for " p eriplasmic t ransaminase A " An in-frame-deleted ptaA mutant selectively lacked the α-ketoglutaric acid form of pyoverdine, and recombinant PtaA complemented this phenotype. The ptaA / pvdN double mutant produced exclusively the glutamic acid form of pyoverdine. PtaA is homodimeric and contains a pyridoxal phosphate cofactor. Mutation of the active-site lysine abolished PtaA activity and affected folding as well as Tat-dependent transport of the enzyme. In pseudomonads, the occurrence of ptaA correlates with the occurrence of α-ketoglutaric acid forms of pyoverdines. As this enzyme is not restricted to pyoverdine-producing bacteria, its catalysis of periplasmic transaminations is most likely a general tool for specific biosynthetic pathways. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  9. Isolation and characterization of biosurfactant producing bacteria from Persian Gulf (Bushehr provenance).

    Science.gov (United States)

    Hassanshahian, Mehdi

    2014-09-15

    Biosurfactants are surface active materials that are produced by some microorganisms. These molecules increase biodegradation of insoluble pollutants. In this study sediments and seawater samples were collected from the coastline of Bushehr provenance in the Persian Gulf and their biosurfactant producing bacteria were isolated. Biosurfactant producing bacteria were isolated by using an enrichment method in Bushnell-Hass medium with diesel oil as the sole carbon source. Five screening tests were used for selection of Biosurfactant producing bacteria: hemolysis in blood agar, oil spreading, drop collapse, emulsification activity and Bacterial Adhesion to Hydrocarbon test (BATH). These bacteria were identified using biochemical and molecular methods. Eighty different colonies were isolated from the collected samples. The most biosurfactant producing isolates related to petrochemical plants of Khark Island. Fourteen biosurfactant producing bacteria were selected between these isolates and 7 isolates were screened as these were predominant producers that belong to Shewanella alga, Shewanella upenei, Vibrio furnissii, Gallaecimonas pentaromativorans, Brevibacterium epidermidis, Psychrobacter namhaensis and Pseudomonas fluorescens. The largest clear zone diameters in oil spreading were observed for G. pentaromativorans strain O15. Also, this strain has the best emulsification activity and reduction of surface tension, suggesting it is the best of thee isolated strains. The results of this study confirmed that there is high diversity of biosurfactant producing bacteria in marine ecosystem of Iran and by application of these bacteria in petrochemical waste water environmental problems can be assisted. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Study in vitro of the impact of endophytic bacteria isolated from Centella asiatica on the disease incidence caused by the hemibiotrophic fungus Colletotrichum higginsianum.

    Science.gov (United States)

    Rakotoniriana, Erick Francisco; Rafamantanana, Mamy; Randriamampionona, Denis; Rabemanantsoa, Christian; Urveg-Ratsimamanga, Suzanne; El Jaziri, Mondher; Munaut, Françoise; Corbisier, Anne-Marie; Quetin-Leclercq, Joëlle; Declerck, Stéphane

    2013-01-01

    Thirty-one endophytic bacteria isolated from healthy leaves of Centella asiatica were screened in vitro for their ability to reduce the growth rate and disease incidence of Colletotrichum higginsianum, a causal agent of anthracnose. Isolates of Cohnella sp., Paenibacillus sp. and Pantoea sp. significantly stimulated the growth rate of C. higginsianum MUCL 44942, while isolates of Achromobacter sp., Acinetobacter sp., Microbacterium sp., Klebsiella sp. and Pseudomonas putida had no influence on this plant pathogen. By contrast, Bacillus subtilis BCA31 and Pseudomonas fluorescens BCA08 caused a marked inhibition of C. higginsianum MUCL 44942 growth by 46 and 82 %, respectively. Cell-free culture filtrates of B. subtilis BCA31 and P. fluorescens BCA08 were found to contain antifungal compounds against C. higginsianum MUCL 44942. Inoculation assays on in vitro-cultured plants of C. asiatica showed that foliar application of B. subtilis BCA31, three days before inoculation with C. higginsianum MUCL 44942, significantly reduced incidence and severity of the disease. The role of endophytic bacteria in maintaining the apparent inactivity of C. higginsianum MUCL 44942 in C. asiatica grown in the wild is discussed.

  11. Antibiotic resistance patterns of Pseudomonas spp. isolated from the River Danube

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    Clemens eKittinger

    2016-05-01

    Full Text Available Spread and persistence of antibiotic resistance pose a severe threat to human health, yet there is still lack of knowledge about reservoirs of antibiotic resistant bacteria in the environment. We took the opportunity of the Joint Danube Survey 3 (JDS3, the world's biggest river research expedition of its kind in 2013, to analyse samples originating from different sampling points along the whole length of the river. Due to its high clinical relevance, we concentrated on the characterization of Pseudomonas spp. and evaluated the resistance profiles of Pseudomonas spp. which were isolated from eight sampling points. In total, 520 Pseudomonas isolates were found, 344 (66.0% isolates were identified as Pseudomonas putida, and 141 (27.1% as Pseudomonas fluorescens, all other Pseudomonas species were represented by less than five isolates, among those two P. aeruginosa isolates. Thirty seven percent (37% of all isolated Pseudomonas species showed resistance to at least one out of eleven tested antibiotics. The most common resistance was against meropenem (30.4% / 158 isolates piperacillin/tazobactam (10.6% / 55 isolates and ceftazidime (4.2% / 22 isolates. 16 isolates (3.1% / 16 isolates were multi-resistant. For each tested antibiotic at least one resistant isolate could be detected. Sampling points from the upper stretch of the River Danube showed more resistant isolates than downriver. Our results suggest that antibiotic resistance can be acquired by and persists even in Pseudomonas species that are normally not in direct contact with humans. A possible scenario is that these bacteria provide a reservoir of antibiotic resistance genes that can spread to related human pathogens by horizontal gene transfer.

  12. Pathogenic variation in isolates of Pseudomonas causing the brown blotch of cultivated mushroom, Agaricus bisporus

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    Mohamed A. Abou-Zeid

    2012-09-01

    Full Text Available Twenty seven bacterial isolates were isolated from superficial brown discolorations on the caps of cultivated Agaricus bisporus. After White Line Assay (WLA and the assist of Biolog computer-identification system, isolates were divided into groups: (I comprised ninteen bacterial isolates that positively responded to a Pseudomonas "reactans" reference strain (NCPPB1311 in WLA and were identified as Pseudomonas tolaasii, (II comprised two isolates which were WLA+ towards the reference strain (JCM21583 of P. tolaasii and were proposed to be P. "reactans". The third group comprised six isolates, two of which weakly responded to the strain of P. tolaasii and were identified as P. gingeri whereas the other four were WLA- and identified as P. fluorescens (three isolates and P. marginalis (one isolate. Isolates of P. tolaasii showed high aggressiveness compared with those of P. "reactans" in pathogenicity tests. Cubes of 1 cm³ of A. bisporus turned brown and decreased in size when were inoculated with 10 µl of P. tolaasii suspension containing 10(8 CFU ml-1, whereas a similar concentration of P. "reactans" caused only light browning. Fifty µl of the same concentration of P. tolaasii isolates gave typical brown blotch symptoms on fresh mushroom sporophores whereas the two P. "reactans" isolates caused superficial light discoloration only after inoculation with 100 µl of the same concentration. Mixture from both bacterial suspensions increased the brown areas formed on the pileus. This is the first pathogenicity report of P. tolasii and P. "reactans" isolated from cultivated A. bisporus in Egypt.

  13. Different Ancestries of R Tailocins in Rhizospheric Pseudomonas Isolates

    Science.gov (United States)

    Ghequire, Maarten G.K.; Dillen, Yörg; Lambrichts, Ivo; Proost, Paul; Wattiez, Ruddy; De Mot, René

    2015-01-01

    Bacterial genomes accommodate a variety of mobile genetic elements, including bacteriophage-related clusters that encode phage tail-like protein complexes playing a role in interactions with eukaryotic or prokaryotic cells. Such tailocins are unable to replicate inside target cells due to the lack of a phage head with associated DNA. A subset of tailocins mediate antagonistic activities with bacteriocin-like specificity. Functional characterization of bactericidal tailocins of two Pseudomonas putida rhizosphere isolates revealed not only extensive similarity with the tail assembly module of the Pseudomonas aeruginosa R-type pyocins but also differences in genomic integration site, regulatory genes, and lytic release modules. Conversely, these three features are quite similar between strains of the P. putida and Pseudomonas fluorescens clades, although phylogenetic analysis of tail genes suggests them to have evolved separately. Unlike P. aeruginosa R pyocin elements, the tailocin gene clusters of other pseudomonads frequently carry cargo genes, including bacteriocins. Compared with P. aeruginosa, the tailocin tail fiber sequences that act as specificity determinants have diverged much more extensively among the other pseudomonad species, mostly isolates from soil and plant environments. Activity of the P. putida antibacterial particles requires a functional lipopolysaccharide layer on target cells, but contrary to R pyocins from P. aeruginosa, strain susceptibilities surpass species boundaries. PMID:26412856

  14. Effectiveness of cleaning and sanitizing procedures in controlling the adherence of Pseudomonas fluorescens, Salmonella Enteritidis, and Staphylococcus aureus to domestic kitchen surfaces Eficiência dos procedimentos de limpeza e de sanitização no controle da adesão de Pseudomonas fluorescens, Salmonella Enteritidis e Staphylococcus aureus em superfícies usadas em cozinhas domésticas

    Directory of Open Access Journals (Sweden)

    Iara Dias Silva

    2010-03-01

    Full Text Available The effectiveness of cleaning and sanitizing procedures in controlling Staphylococcus aureus, Salmonella Enteritidis, and Pseudomonasfluorescens adhered to granite and stainless steel was evaluated. There was no significant difference (p > 0.05 in the adherence of pure cultures of these microorganisms to stainless steel. The numbers of P. fluorescens and S. Enteritidis adhered to granite were greater (p 0.05 between the surfaces. However, a significant difference was observed (p A eficiência dos procedimentos de limpeza e sanitização no controle de Staphylococcus aureus, Salmonella Enteritidis e Pseudomonasfluorescens aderidas em granito e aço inoxidável foi avaliada. Não houve diferença significativa (p > 0,05 na adesão destes microrganismos quando em cultura pura, em aço inoxidável. O número de células aderidas de P. fluorescens e S. Enteritidis foi maior (p 0,05 entre as superfícies. Entretanto, observou-se uma diferença (p < 0,05 entre as soluções sanitizantes utilizadas. Hipoclorito de sódio e ácido peracético apresentaram maior ação bactericida (p < 0,05 que o composto de amônia quaternária. Observou-se que S. aureus apresentou menor resistência à ação desses sanitizantes. Os resultados mostram a importância da adequada realização dos procedimentos de limpeza e sanitização para evitar a adesão bacteriana e formação de biofilme.

  15. Immobilization of Pseudomonas fluorescens lipase on hydrophobic supports and application in biodiesel synthesis by transesterification of vegetable oils in solvent-free systems.

    Science.gov (United States)

    Lima, Lionete N; Oliveira, Gladson C; Rojas, Mayerlenis J; Castro, Heizir F; Da Rós, Patrícia C M; Mendes, Adriano A; Giordano, Raquel L C; Tardioli, Paulo W

    2015-04-01

    This work describes the preparation of biocatalysts for ethanolysis of soybean and babassu oils in solvent-free systems. Polystyrene, Amberlite (XAD-7HP), and octyl-silica were tested as supports for the immobilization of Pseudomonas fluorescens lipase (PFL). The use of octyl-silica resulted in a biocatalyst with high values of hydrolytic activity (650.0 ± 15.5 IU/g), immobilization yield (91.3 ± 0.3 %), and recovered activity (82.1 ± 1.5 %). PFL immobilized on octyl-silica was around 12-fold more stable than soluble PFL, at 45 °C and pH 8.0, in the presence of ethanol at 36 % (v/v). The biocatalyst provided high vegetable oil transesterification yields of around 97.5 % after 24 h of reaction using babassu oil and around 80 % after 48 h of reaction using soybean oil. The PFL-octyl-silica biocatalyst retained around 90 % of its initial activity after five cycles of transesterification of soybean oil. Octyl-silica is a promising support that can be used to immobilize PFL for subsequent application in biodiesel synthesis.

  16. Multiple-level regulation of 2,4-diacetylphloroglucinol production by the sigma regulator PsrA in Pseudomonas fluorescens 2P24.

    Directory of Open Access Journals (Sweden)

    Xiaogang Wu

    Full Text Available BACKGROUND: Pseudomonas fluorescens 2P24 is a rhizospheric bacterium that aggressively colonizes the plant roots. It produces the antibiotic 2,4-diacetylphoroglucinol (2,4-DAPG, which contributes to the protection of various crop plants against soil borne diseases caused by bacterial and fungal pathogens. The biosynthesis of 2,4-DAPG is regulated at the transcriptional level in the expression of the phlACBD operon as well as at the posttranscriptional level by the Gac/Rsm signal transduction pathway. However, the detailed mechanism of such regulation is not clear. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we identified a binding site for the sigma regulator PsrA in the promoter region of the phlA gene. Electrophoretic mobility shift experiments revealed direct and specific binding of PsrA to the phlA promoter region. Consistent with the fact that its binding site locates within the promoter region of phlA, PsrA negatively regulates phlA expression, and its inactivation led to significant increase in 2,4-DAPG production. Interestingly, PsrA also activates the expression of the sigma factor RpoS, which negatively regulates 2,4-DAPG production by inducing the expression of the RNA-binding protein RsmA. CONCLUSIONS/SIGNIFICANCE: These results suggest that PsrA is an important regulator that modulates 2,4-DAPG biosynthesis at both transcriptional and posttranscriptional levels.

  17. Adaptive radiation of Pseudomonas fluorescens SBW25 in experimental microcosms provides an understanding of the evolutionary ecology and molecular biology of A-L interface biofilm formation.

    Science.gov (United States)

    Koza, Anna; Kusmierska, Anna; McLaughlin, Kimberley; Moshynets, Olena; Spiers, Andrew J

    2017-07-03

    Combined experimental evolutionary and molecular biology approaches have been used to investigate the adaptive radiation of Pseudomonas fluorescens SBW25 in static microcosms leading to the colonisation of the air-liquid interface by biofilm-forming mutants such as the Wrinkly Spreader (WS). In these microcosms, the ecosystem engineering of the early wild-type colonists establishes the niche space for subsequent WS evolution and colonisation. Random WS mutations occurring in the developing population that deregulate diguanylate cyclases and c-di-GMP homeostasis result in cellulose-based biofilms at the air-liquid interface. These structures allow Wrinkly Spreaders to intercept O2 diffusing into the liquid column and limit the growth of competitors lower down. As the biofilm matures, competition increasingly occurs between WS lineages, and niche divergence within the biofilm may support further diversification before system failure when the structure finally sinks. A combination of pleiotropic and epistasis effects, as well as secondary mutations, may explain variations in WS phenotype and fitness. Understanding how mutations subvert regulatory networks to express intrinsic genome potential and key innovations providing a selective advantage in novel environments is key to understanding the versatility of bacteria, and how selection and ecological opportunity can rapidly lead to substantive changes in phenotype and in community structure and function. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. Effect of aluminium and copper on biofilm development of Pseudomonas pseudoalcaligenes KF707 and P. fluorescens as a function of different media compositions.

    Science.gov (United States)

    Booth, Sean C; George, Iain F S; Zannoni, Davide; Cappelletti, Martina; Duggan, Gavin E; Ceri, Howard; Turner, Raymond J

    2013-06-01

    Bioremediation efforts worldwide are faced with the problem of metals interfering with the degradation of organic pollutants. There has been little systematic investigation into how the important environmental factors of media composition, buffering agent, and carbon source affect the exertion of metal toxicity on bacteria. This study aimed to systematically separate and investigate the influence of these factors by examining planktonic and biofilm establishment and growth. Two Pseudomonads were chosen, the PCB degrader P. pseudoalcaligenes KF707 and P. fluorescens. The two strains were grown in the presence of Al(3+) and Cu(2+) under different media conditions of carbon source (Lysogeny broth, biphenyl, succinate, aspartic acid, butyric acid, oxaloacetic acid, putrescine and benzoic acid) and under different buffering conditions (high and low phosphate or MOPS). These experiments allowed for the elucidation of an effect of different metabolic conditions and metal speciation on planktonic bacteria growth and biofilm establishment and development under metal stress. Here we show that the nature of bacterial growth (planktonic and biofilm development) is dramatically affected by the interplay between toxic metals, carbon source and media composition. The capacity of a media to bind toxic metals as well as quality of carbon source greatly influences the amount of metal that bacteria can tolerate, depending on both the bacterium and metal. Future studies evaluating metal ion toxicity should consider these effects, as well as their interactions with specific environments into account in order to improve clean-up success.

  19. Polymorphism of a lipid extract from Pseudomonas fluorescens: Structure analysis of a hexagonal phase and of a novel cubic phase of extinction symbol Fd--

    International Nuclear Information System (INIS)

    Mariani, P.; Rivas, E.; Delacroix, H.; Luzzati, V.

    1990-01-01

    The phase diagram of the Pseudomonas fluorescens lipid extract is unusual, in the sense that it displays a cubic phase straddled by a hexagonal phase. The hexagonal phase was studied over an extended concentration range, and the reflections were phased on the assumption that the structure contains circular cylinders of known radius. The cubic phase, whose extinction symbol is Fd--, was analyzed by reference to space group No. 227 (Fd3m). The phases of the reflections were determined by using a novel pattern recognition approach, based upon the notion that the average fourth power of the electron density contrast 4 > is dependent on chemical composition but not on physical structure, provided that the function Δr(r) satisfies the constraints = 0 and 2 > = 1. The authors analyzed two cubic samples of different composition: for each of them they generated all the phase combinations compatible with the X-ray scattering data and they searched for those whose 4 > best agrees with the hexagonal phase. They concluded that the chemical composition of the phases being compared must be identical, that the X-ray scattering data should not be truncated artificially, and that the apodization must be mild so that the curvature takes a value intermediate between those corresponding to the raw data of the two phases. The structure may be visualized as a 3D generalization of the lipid monolayer. The structure, moreover, does not belong to the class of the infinite periodic surfaces without intersections

  20. Proteolytic activity of protease produced by Pseudomonas fluorescens IB 2312 in skimmed milk subject to the process of high pressure homogenization

    Directory of Open Access Journals (Sweden)

    Claudia Regina Gonçalves Pinho

    2014-08-01

    Full Text Available The presence of thermoresistant proteases produced by psychrotrophic microorganisms have been identified as a limiting factor of the UHT milk shelflife, causing undesirable changes in milk products. High pressure homogenization (HPH processing is a non-thermal method of food preservation, able to promotes the microbiological safety and inactivation of some enzymes. Thus, this work assessed the proteolytic activity of protease produced by Pseudomonas fluorescens in skim milk subjected to high pressure homogenization process. The milk samples were added by the protease enzymatic extract (10% v/v and subjected to pressures up to 300 MPa. The assays showed that pressures on the order of 300 MPa caused a 72.5% reduction in proteolytic activity. Therefore, the process at high pressures resulted in significant inactivation of this thermoresistent enzyme, which possibly favors the shelf-life extension of the UHT milk and also limits the yield and quality loss of cheeses due to undesirable sensory changes in flavor and texture caused by this enzyme.

  1. Efficacy of Pseudomonas fluorescens strain CL145A spray dried powder for controlling zebra mussels adhering to native unionid mussels within field enclosures

    Science.gov (United States)

    Luoma, James A.; Weber, Kerry L.; Severson, Todd J.; Mayer, Denise A.

    2015-01-01

    The efficacy of a commercially prepared spray dried powder (SDP) formulation of Pseudomonas fluorescens (strain CL145A) was evaluated for removing zebra mussels (Dreissena polymorpha) adhering to a population of unionid mussels in Lake Darling (Alexandria, Minnesota). Two groups of unionid mussels were used in the study. Unionid mussels were collected near the test area, weighed, photographed, individually tagged, and randomly allocated to one of nine test enclosures in equal proportions and then divided into two groups. The first group of unionid mussels (Group 1, n = 5 per test enclosure) were indiscriminately selected from each test enclosure and used to estimate the number of zebra mussels adhering to unionid mussels prior to exposure. The second group of unionid mussels (Group 2, n = 22 per test enclosure) were used to evaluate the efficacy of SDP for removal of adhering zebra mussels. Both Group 1 and Group 2 mussels were used to evaluate the effects of SDP exposure on unionid mussel survival.

  2. Functional Characterization of the Mannitol Promoter of Pseudomonas fluorescens DSM 50106 and Its Application for a Mannitol-Inducible Expression System for Pseudomonas putida KT2440.

    Directory of Open Access Journals (Sweden)

    Jana Hoffmann

    Full Text Available A new pBBR1MCS-2-derived vector containing the Pseudomonas fluorescens DSM10506 mannitol promoter PmtlE and mtlR encoding its AraC/XylS type transcriptional activator was constructed and optimized for low basal expression. Mannitol, arabitol, and glucitol-inducible gene expression was demonstrated with Pseudomonas putida and eGFP as reporter gene. The new vector was applied for functional characterization of PmtlE. Identification of the DNA binding site of MtlR was achieved by in vivo eGFP measurement with PmtlE wild type and mutants thereof. Moreover, purified MtlR was applied for detailed in vitro investigations using electrophoretic mobility shift assays and DNaseI footprinting experiments. The obtained data suggest that MtlR binds to PmtlE as a dimer. The proposed DNA binding site of MtlR is AGTGC-N5-AGTAT-N7-AGTGC-N5-AGGAT. The transcription activation mechanism includes two binding sites with different binding affinities, a strong upstream binding site and a weaker downstream binding site. The presence of the weak downstream binding site was shown to be necessary to sustain mannitol-inducibility of PmtlE. Two possible functions of mannitol are discussed; the effector might stabilize binding of the second monomer to the downstream half site or promote transcription activation by inducing a conformational change of the regulator that influences the contact to the RNA polymerase.

  3. Biosurfactant production by Pseudomonas strains isolated from floral nectar.

    Science.gov (United States)

    Ben Belgacem, Z; Bijttebier, S; Verreth, C; Voorspoels, S; Van de Voorde, I; Aerts, G; Willems, K A; Jacquemyn, H; Ruyters, S; Lievens, B

    2015-06-01

    To screen and identify biosurfactant-producing Pseudomonas strains isolated from floral nectar; to characterize the produced biosurfactants; and to investigate the effect of different carbon sources on biosurfactant production. Four of eight nectar Pseudomonas isolates were found to produce biosurfactants. Phylogenetic analysis based on three housekeeping genes (16S rRNA gene, rpoB and gyrB) classified the isolates into two groups, including one group closely related to Pseudomonas fluorescens and another group closely related to Pseudomonas fragi and Pseudomonas jessenii. Although our nectar pseudomonads were able to grow on a variety of water-soluble and water-immiscible carbon sources, surface active agents were only produced when using vegetable oil as sole carbon source, including olive oil, sunflower oil or waste frying sunflower oil. Structural characterization based on thin layer chromatography (TLC) and ultra high performance liquid chromatography-accurate mass mass spectrometry (UHPLC-amMS) revealed that biosurfactant activity was most probably due to the production of fatty acids (C16:0; C18:0; C18:1 and C18:2), and mono- and diglycerides thereof. Four biosurfactant-producing nectar pseudomonads were identified. The active compounds were identified as fatty acids (C16:0; C18:0; C18:1 and C18:2), and mono- and diglycerides thereof, produced by hydrolysis of triglycerides of the feedstock. Studies on biosurfactant-producing micro-organisms have mainly focused on microbes isolated from soils and aquatic environments. Here, for the first time, nectar environments were screened as a novel source for biosurfactant producers. As nectars represent harsh environments with high osmotic pressure and varying pH levels, further screening of nectar habitats for biosurfactant-producing microbes may lead to the discovery of novel biosurfactants with broad tolerance towards different environmental conditions. © 2015 The Society for Applied Microbiology.

  4. Effect of nutrients and fermentation conditions on the production of biosurfactants using rhizobacteria isolated from fique plants

    Directory of Open Access Journals (Sweden)

    Aura M. Pedroza-Rodríguez

    2010-12-01

    Full Text Available To isolate biosurfactant-producing microorganisms from the rhizosphere of fique and to select the best genus to evaluate theeffect of nutritional and fermentation conditions on the production of rhamnolipids. Materials and methods. Rhizospheric soil wassampled in three areas of Cauca. The best genus was selected for the experimental designs (Plackett Burman and 22 factorial and to find theproduction conditions for the growth kinetics at an Erlenmeyer flask scale. Results. Isolates from the rhizosphere of fique plants were fromgroups (or genera of Bacillus, Pseudomonas and Actinomycetes, being Pseudomonas the more responsive in preliminary testing foremulsification. From the results of the experimental designs and the kinetics of production, we found that rhamnose synthesis associatedwith rhamnolipids (3.2 g/l and emulsification (68% EC24 was significantly favored (p <0.0001 by cultivating an inoculum of 10% v/vof Pseudomonas fluorescens in a medium composed of: soybean oil 2% (v/v, K2HPO40.2% (w/v, yeast extract 0.4 g/l, NH4NO33.7 g/l, 1 ml trace elements (CoCl320 mg/l, H3BO330 mg/l, ZnSO410 mg/l, Cu2SO41 mg/l, Na2MoO43 mg/l, FeSO410 mg/l MnSO42,6 mg/l and pH 7.2. Conclusion. Of all the microbial genera isolated from the rhizosphere of fique, Pseudomonas fluorescens had the greatestpotential in the production of biosurfactants of the rhamnolipids family.

  5. Isolation of Fungal Species from Fermentating Pearl Millet Gruel and ...

    African Journals Online (AJOL)

    Escherichia coli, Staphylococcus aureus, Bacillus cereus, Bacillus lichieniformis, Salmonella spp., Pseudomonas fluorescens, Pseudomonas aeruginosa, Pseudomonas syringae, Proteus sp. and Serratia sp. were utilized as indicator organisms. Secondary metabolites were also extracted from the respective moulds and ...

  6. Isolation and characterization of Fenitrothion-degrading bacteria from pestachio gardens in Kerman Provinance

    Directory of Open Access Journals (Sweden)

    Mehrnosh Ghafari

    2014-07-01

    Full Text Available   Introduction : Pesticides with complex structure have high persistence in ecosystem and biosphere. Pesticides have harmful effects on farmlands, human and natural resources.   Materials and methods: In this study for isolation of pesticide-degrading bacteria (Fenitrothion soil samples were collected from pistachio gardens in Kerman province. Collected soil samples were enriched in Bushnell Hass medium with this pesticide as only carbon and energy source. Isolated bacteria were identified by amplification of 16S rDNA gene by PCR and sequencing .   Results : In this study three Fenitrothion -degrading bacterial strains were isolated. These isolated bacteria were identified as: Pseudomonas fluorescens strain F1 ، Bacillus cereus strain F3 and pseudomonas aeruginosa strain F4 . The effects of pesticides concentration on each dominant bacterial strain were investigated. For Fenitrothion degrading bacterium (F4 strain growth continue until 100 ppm and then decreased. The result of Gas Chromatography (GC analysis confirmed the biodegradation ability of selected bacterial strains .   Discussion and conclusion : The results of this study demonstrated that there is a diversity of pesticide-degrading bacteria (Fenitrothion in soil ecosystem farmlands of Kerman province. It is seemed by application of these pesticide-degrading bacteria in farmlands and using bioremediation technique the ecosystem contamination of pesticide can be decreased.

  7. Evidence for a role of biosurfactants produced by Pseudomonas fluorescens in the spoilage of fresh aerobically stored chicken meat.

    Science.gov (United States)

    Mellor, Glen E; Bentley, Jessica A; Dykes, Gary A

    2011-08-01

    Fresh chicken meat is a fat-rich environment and we therefore hypothesised that production of biosurfactants to increase bioavailability of fats may represent one way in which spoilage bacteria might enhance the availability of nutrients. Numbers of Pseudomonas were determined on a total of 20 fresh and 20 spoiled chicken thighs with skin. A total of 400 randomly isolated Pseudomonas colonies from fresh (200) and spoiled (200) chicken were screened for the presence of biosurfactant production. Biosurfactant producing strains represented 5% and 72% of the Pseudomonas spp. isolates from fresh (mean count 2.3 log(10) cfu g(-1)) and spoiled (mean count 7.4 log(10) cfu g(-1)) chicken skin, respectively. Partially-purified biosurfactants derived from a subgroup of four Pseudomonasfluorescens strains obtained through the screening process were subsequently used to investigate the role that the addition of these compounds plays in the spoilage of aerobically stored chicken. Emulsification potential of the four selected biosurfactants was measured against a range of hydrocarbons and oils. All four biosurfactants displayed a greater ability to emulsify rendered chicken fat than hydrocarbons (paraffin liquid, toluene and hexane) and oils (canola, olive, sunflower and vegetable). Storage trials (4 °C) of chicken meat treated with the four selected biosurfactants revealed a significantly greater (P biosurfactant treated samples, as compared to untreated samples on each day (0, 1, 2, 3) of storage. For biosurfactant treated samples the greatest increase in total aerobic count (1.3-1.7 log(10) cfu g(-1)) occurred following one day of incubation. These results indicate that biosurfactants produced by Pseudomonas spp. may play an important role in the spoilage of aerobically stored chicken meat by making nutrients more freely available and providing strains producing them with a competitive advantage. Copyright © 2011 Elsevier Ltd. All rights reserved.

  8. Spoilage potential of Pseudomonas species isolated from goat milk.

    Science.gov (United States)

    Scatamburlo, T M; Yamazi, A K; Cavicchioli, V Q; Pieri, F A; Nero, L A

    2015-02-01

    Pseudomonas spp. are usually associated with spoilage microflora of dairy products due to their proteolytic potential. This is of particular concern for protein-based products, such as goat milk cheeses and fermented milks. Therefore, the goal of the present study was to characterize the proteolytic activity of Pseudomonas spp. isolated from goat milk. Goat milk samples (n=61) were obtained directly from bulk tanks on dairy goat farms (n=12), and subjected to a modified International Organization for Standardization (ISO) protocol to determine the number and proteolytic activity of Pseudomonas spp. Isolates (n=82) were obtained, identified by PCR, and subjected to pulsed-field gel electrophoresis with XbaI macro-restriction. Then, the isolates were subjected to PCR to detect the alkaline protease gene (apr), and phenotypic tests were performed to check proteolytic activity at 7°C, 25°C, and 35°C. Mean Pseudomonas spp. counts ranged from 2.9 to 4.8 log cfu/mL, and proteolytic Pseudomonas spp. counts ranged from 1.9 to 4.6 log cfu/mL. All isolates were confirmed to be Pseudomonas spp., and 41 were identified as Pseudomonas fluorescens, which clustered into 5 groups sharing approximately 82% similarity. Thirty-six isolates (46.9%) were positive for the apr gene; and 57 (69.5%) isolates presented proteolytic activity at 7°C, 82 (100%) at 25°C, and 64 (78%) at 35°C. The isolates were distributed ubiquitously in the goat farms, and no relationship among isolates was observed when the goat farms, presence of apr, pulsotypes, and proteolytic activity were taken into account. We demonstrated proteolytic activity of Pseudomonas spp. present in goat milk by phenotypic and genotypic tests and indicated their spoilage potential at distinct temperatures. Based on these findings and the ubiquity of Pseudomonas spp. in goat farm environments, proper monitoring and control of Pseudomonas spp. during production are critical. Copyright © 2015 American Dairy Science Association

  9. Prokaryotic Homologs of the Eukaryotic 3-Hydroxyanthranilate 3,4-Dioxygenase and 2-Amino-3-Carboxymuconate-6-Semialdehyde Decarboxylase in the 2-Nitrobenzoate Degradation Pathway of Pseudomonas fluorescens Strain KU-7†

    OpenAIRE

    Muraki, Takamichi; Taki, Masami; Hasegawa, Yoshie; Iwaki, Hiroaki; Lau, Peter C. K.

    2003-01-01

    The 2-nitrobenzoic acid degradation pathway of Pseudomonas fluorescens strain KU-7 proceeds via a novel 3-hydroxyanthranilate intermediate. In this study, we cloned and sequenced a 19-kb DNA locus of strain KU-7 that encompasses the 3-hydroxyanthranilate meta-cleavage pathway genes. The gene cluster, designated nbaEXHJIGFCDR, is organized tightly and in the same direction. The nbaC and nbaD gene products were found to be novel homologs of the eukaryotic 3-hydroxyanthranilate 3,4-dioxygenase a...

  10. INOCULACIÓN AL SUELO CON Pseudomonas fluorescens, Azospirillum oryzae, Bacillus subtilis Y MICROORGANISMOS DE MONTAÑA (MM Y SU EFECTO SOBRE UN SISTEMA DE ROTACIÓN SOYA-TOMATE BAJO CONDICIONES DE INVERNADERO

    Directory of Open Access Journals (Sweden)

    Leida Castro Barquero

    2015-01-01

    Full Text Available Se evaluó un sistema de rotación soya- tomate, con incorporación de biomasa verde y aplicación de inóculos microbianos individuales y en mezcla sobre el crecimiento de las plantas y propiedades edáficas; para ello se evaluaron en invernadero por 24 meses los siguientes 9 trata - mientos: solo tomate (T; rotación tomate-soya (TS; rotación tomate-soya con inoculaciones individuales de Azospirillum oryzae (A; de Pseudomonas fluorescens (P; de Bacillus sub - tilis (B; de microorganismos de montaña (MM; y las inoculaciones en mezcla de B. subtilis y P. fluorescens (BP; de B. subtilis, P. fluorescens y A. oryzae ( BPA; d e B. subtilis , P. fluorescens , Azospirillum sp. y MM (BPAMM. Se evalua - ron las variables físicas: densidad aparente y de partículas; conductividad hidráulica; poros totales; estabilidad de agregados; resistencia a la penetración (RP; las variables químicas: pH; conductividad eléctrica; contenido de N y C; relación C/N; contenido de nutrientes en suelos y foliares; las variables biológicas: respiración de suelos, unidades formadoras de colonias de hongos, bacterias y actinomicetos y el peso fres - co y seco foliar. Las variables físicas no fueron afectadas por los tratamientos, con excepción de RP, que fue mayor en el tratamiento T. Las varia - bles biológicas y químicas fueron sensibles a los tratamientos, con valores significativamente más altos en presencia de MM. Destaca el incremento del P en solución de suelo en tratamientos a los que se adicionó MM: pasó de 6 a 20 mg.l -1 ; esta condición se reflejó además en la cantidad de P en el tejido foliar al final del ensayo. Se determi - nó que el pH, CE y la respiración del suelo fueron afectados por la interacción entre los tratamientos aplicados y el tiempo transcurrido; los mayores valores se obtuvieron al final del ensayo y en los tratamientos con MM.

  11. Inoculación al suelo con Pseudomonas fluorescens, Azospirillum oryzae, Bacillus subtilis y microorganismos de montaña (mm y su efecto sobre un sistema de rotación soya-tomate bajo condiciones de invernadero

    Directory of Open Access Journals (Sweden)

    Leida Castro Barquero

    2015-11-01

    Full Text Available Se evaluó un sistema de rotación soyatomate, con incorporación de biomasa verde y aplicación de inóculos microbianos individuales y en mezcla sobre el crecimiento de las plantas y propiedades edáficas; para ello se evaluaron en invernadero por 24 meses los siguientes 9 tratamientos: solo tomate (T; rotación tomate-soya (TS; rotación tomate-soya con inoculaciones individuales de Azospirillum oryzae (A; de Pseudomonas fluorescens (P; de Bacillus subtilis (B; de microorganismos de montaña (MM; y las inoculaciones en mezcla de B. subtilis y P. fluorescens (BP; de B. subtilis, P. fluorescens y A. oryzae (BPA; de B. subtilis, P. fluorescens, Azospirillum sp. y MM (BPAMM. Se evaluaron las variables físicas: densidad aparente y de partículas; conductividad hidráulica; poros totales; estabilidad de agregados; resistencia a la penetración (RP; las variables químicas: pH; conductividad eléctrica; contenido de N y C; relación C/N; contenido de nutrientes en suelos y foliares; las variables biológicas: respiración de suelos, unidades formadoras de colonias de hongos, bacterias y actinomicetos y el peso fresco y seco foliar. Las variables físicas no fueron afectadas por los tratamientos, con excepción de RP, que fue mayor en el tratamiento T. Las variables biológicas y químicas fueron sensibles a los tratamientos, con valores significativamente más altos en presencia de MM. Destaca el incremento del P en solución de suelo en tratamientos a los que se adicionó MM: pasó de 6 a 20 mg.l-1; esta condición se reflejó además en la cantidad de P en el tejido foliar al final del ensayo. Se determinó que el pH, CE y la respiración del suelo fueron afectados por la interacción entre los tratamientos aplicados y el tiempo transcurrido; los mayores valores se obtuvieron al final del ensayo y en los tratamientos con MM.

  12. Isolation and characterization of biosurfactant producing bacteria from Persian Gulf (Bushehr provenance)

    International Nuclear Information System (INIS)

    Hassanshahian, Mehdi

    2014-01-01

    Highlights: • Biosurfactant producing bacteria were isolated from Persian Gulf. • There is high diversity of biosurfactant producing bacteria in the Persian Gulf. • These bacteria are very useful for management of oil pollution in the sea. - Abstract: Biosurfactants are surface active materials that are produced by some microorganisms. These molecules increase biodegradation of insoluble pollutants. In this study sediments and seawater samples were collected from the coastline of Bushehr provenance in the Persian Gulf and their biosurfactant producing bacteria were isolated. Biosurfactant producing bacteria were isolated by using an enrichment method in Bushnell-Hass medium with diesel oil as the sole carbon source. Five screening tests were used for selection of Biosurfactant producing bacteria: hemolysis in blood agar, oil spreading, drop collapse, emulsification activity and Bacterial Adhesion to Hydrocarbon test (BATH). These bacteria were identified using biochemical and molecular methods. Eighty different colonies were isolated from the collected samples. The most biosurfactant producing isolates related to petrochemical plants of Khark Island. Fourteen biosurfactant producing bacteria were selected between these isolates and 7 isolates were screened as these were predominant producers that belong to Shewanella alga, Shewanella upenei, Vibrio furnissii, Gallaecimonas pentaromativorans, Brevibacterium epidermidis, Psychrobacter namhaensis and Pseudomonas fluorescens. The largest clear zone diameters in oil spreading were observed for G. pentaromativorans strain O15. Also, this strain has the best emulsification activity and reduction of surface tension, suggesting it is the best of thee isolated strains. The results of this study confirmed that there is high diversity of biosurfactant producing bacteria in marine ecosystem of Iran and by application of these bacteria in petrochemical waste water environmental problems can be assisted

  13. Enhanced biosorption of mercury(II) and cadmium(II) by cold-induced hydrophobic exobiopolymer secreted from the psychrotroph Pseudomonas fluorescens BM07

    Energy Technology Data Exchange (ETDEWEB)

    Zamil, Sheikh Shawkat; Choi, Mun Hwan; Song, Jung Hyun; Park, Hyunju; Xu, Ju; Yoon, Sung Chul [Gyeongsang National Univ., Jinju (Korea). Nano-Biomaterials Science Lab.; Chi, Ki-Whan [Ulsan Univ. (Korea). Dept. of Chemistry

    2008-09-15

    The cells of psychrotrophic Pseudomonas fluorescens BM07 were found to secrete large amounts of exobiopolymer (EBP) composed of mainly hydrophobic (water insoluble) polypeptide(s) (as contain {proportional_to}50 mol% hydrophobic amino acids, lacking cysteine residue) when grown on fructose containing limited M1 medium at the temperatures as low as 0-10 C but trace amount at high (30 C, optimum growth) temperature. Two types of nonliving BM07 cells (i.e., cells grown at 30 C and 10 C) as well as the freeze-dried EBP were compared for biosorption of mercury (Hg(II)) and cadmium (Cd(II)). The optimum adsorption pH was found 7 for Hg(II) but 6 for Cd(II), irrespective of the type of biomass. Equilibrium adsorption data well fitted the Langmuir adsorption model. The maximum adsorption (Q{sub max}) was 72.3, 97.4, and 286.2 mg Hg(II)/g dry biomass and 18.9, 27.0, and 61.5 mg Cd(II)/g dry biomass for cells grown at 30 C and 10 C and EBP, respectively, indicating major contribution of heavy metal adsorption by cold-induced EBP. Mercury(II) binding induced a significant shift of infrared (IR) amide I and II absorption of EBP whereas cadmium(II) binding showed only a very little shift. These IR shifts demonstrate that mercury(II) and cadmium(II) might have different binding sites in EBP, which was supported by X-ray diffraction and differential scanning calorimetric analysis and sorption results of chemically modified biomasses. This study implies that the psychrotrophs like BM07 strain may play an important role in the bioremediation of heavy metals in the temperate regions especially in the inactive cold season. (orig.)

  14. Role of the GacS sensor kinase in the regulation of volatile production by plant growth-promoting Pseudomonas fluorescens SBW25

    Directory of Open Access Journals (Sweden)

    Xu Cheng

    2016-11-01

    Full Text Available In plant-associated Pseudomonas species, the production of several secondary metabolites and exoenzymes is regulated by the GacS/GacA two-component regulatory system (the Gac-system. Here, we investigated if a mutation in the GacS sensor kinase affects the production of volatile organic compounds (VOCs in P. fluorescens SBW25 (Pf.SBW25 and how this impacts on VOCs-mediated growth promotion and induced systemic resistance of Arabidopsis and tobacco. A total of 205 VOCs were detected by Gas Chromatography Mass Spectrometry (GC-MS for Pf. SBW25 and the gacS-mutant grown on 2 different media for 3 and 6 days. Discriminant function analysis followed by hierarchical clustering revealed 24 VOCs that were significantly different in their abundance between Pf.SBW25 and the gacS-mutant, which included three acyclic alkenes (3-nonene, 4-undecyne, 1-undecene. These alkenes were significantly reduced by the gacS mutation independently of the growth media and of the incubation time. For Arabidopsis, both Pf.SBW25 and the gacS-mutant enhanced, via VOCs, root and shoot biomass, induced systemic resistance against leaf infections by P. syringae and rhizosphere acidification to the same extent. For tobacco, however, VOCs-mediated effects on shoot and root growth were significantly different between Pf.SBW25 and the gacS-mutant. While Pf.SBW25 inhibited tobacco root growth, the gacS-mutant enhanced root biomass and lateral root formation relative to the non-treated control plants. Collectively these results indicate that the sensor kinase GacS is involved in the regulation of VOCs production in Pf.SBW25, affecting plant growth in a plant species-dependent manner.

  15. Improvement of a dry formulation of Pseudomonas fluorescens EPS62e for fire blight disease biocontrol by combination of culture osmoadaptation with a freeze-drying lyoprotectant.

    Science.gov (United States)

    Cabrefiga, J; Francés, J; Montesinos, E; Bonaterra, A

    2014-10-01

    To study the effect of lyoprotectants and osmoadaptation on viability of Pseudomonas fluorescens EPS62e during freeze-drying and storage and to evaluate the formulation in terms of efficacy in biocontrol and fitness on pear flowers. A wettable powder formulation of a biocontrol agent of fire blight was optimized by means of lyoprotectants and culture osmoadaptation. Freeze-drying was used to obtain dehydrated cells, and the best viability (70% of survival) was obtained using lactose as lyoprotectant. Survival during lyophilization was additionally improved using physiological adaptation of cells during cultivation under salt-amended medium (osmoadaptation). The procedure increased the survival of cells after freeze-drying attaining viability values close to a 100% in the lactose-formulated product (3 × 10(11) CFU g(-1) ), and through the storage period of 1 year at 4°C. The dry formulation showed also an improved biocontrol efficacy and survival of EPS62e on pear flowers under low relative humidity conditions. Cell viability after freeze-drying was improved using lactose as lyoprotectant combined with a procedure of osmoadaptation during cultivation. The powder-formulated product remained active for 12 months and retained biocontrol levels similar to that of fresh cells. The formulation showed an improved survival of EPS62e on flowers and an increase of the efficacy of biocontrol of fire blight at low relative humidity. The results have a potential value for commercial application in biocontrol agents not only of fire blight but also of other plant diseases. © 2014 The Society for Applied Microbiology.

  16. Salicylic acid degradation from aqueous solutions using Pseudomonas fluorescens HK44: parameters studies and application tools Degradação de ácido salicílico presente em soluções sintéticas utilizando Pseudomonas fluorescens HK44

    Directory of Open Access Journals (Sweden)

    Tatyane R. Silva

    2007-03-01

    Full Text Available The optimal conditions for salicylic acid biodegradation by Pseudomonas fluorescens HK44 were determined in this study with the intention to create a microbial sensor. Kinetic experiments permitted a definition of 60 and 30min the time needed to achieve the maximum degradation of salicylic acid presented in a medium with and without yeast extract, respectively. The degradation in medium without yeast extract and the quantification by spectrophotometry 230 nm were selected to be used in further tests. The use of preactivated cells or on the exponential growth phase showed better salicylic acid degradation percentages when compared to nonactivated cells or on the stationary growth state. Finally, the best cellular concentration used on the salicylic acid degradation was 0,1 g.L-1. Strain HK44 shows to be capable of degrade salicylic acid presented in simple aqueous systems, making this strain a promising tool for the application on a luminescent microbial sensor.Com a intenção de criar um sensor microbiano, as condições ótimas para a biodegradação de ácido salicílico por Pseudomonas fluorescens HK44 foram determinadas neste estudo. Os experimentos cinéticos permitiram a definição dos tempos de 60 e 30 minutos como necessários para atingir a máxima degradação de ácido salicílico presente em meio com ou sem extrato de lêvedo, respectivamente. A degradação no meio sem extrato de lêvedo e a quantificação através de espectrofotometria 230 nm foram selecionadas para serem utilizadas em testes posteriores. O uso de células pré-ativadas ou na fase exponencial de crescimento apresentou melhores porcentagens de degradação de ácido salicílico quando comparadas a células não-ativadas ou no estado estacionário de crescimento. Além disso, a melhor concentração celular utilizada nessa degradação foi 0,1 g.L¹. A cepa HK44 parece ser capaz de degradar o ácido salicílico presente em sistemas aquosos simples, tornando este

  17. Isolation, molecular and biochemical characterization of oil ...

    African Journals Online (AJOL)

    ... P. aerugi-nosa, P. alcaligenes, P. fluorescens, P. cepacia, P. mallei, P. maltophilia, P. oleovorans, P. putida, P. stutzeri P. vesicularis, Acinetobacter calcoaceticus, Ac. lowffii, Micro-ococcus luteus , M. varians, M. lylae, M. roseus, Alcaligenes denitrificians, Bacillus megaterium, Comamonas sp., Moraxella sp., Bordetella sp., ...

  18. Kinetics of biofilm formation and desiccation survival of Listeria monocytogenes in single and dual species biofilms with Pseudomonas fluorescens, Serratia proteamaculans or Shewanella baltica on food-grade stainless steel surfaces.

    Science.gov (United States)

    Daneshvar Alavi, Hessam Edin; Truelstrup Hansen, Lisbeth

    2013-01-01

    This study investigated the dynamics of static biofilm formation (100% RH, 15 °C, 48-72 h) and desiccation survival (43% RH, 15 °C, 21 days) of Listeria monocytogenes, in dual species biofilms with the common spoilage bacteria, Pseudomonas fluorescens, Serratia proteamaculans and Shewanella baltica, on the surface of food grade stainless steel. The Gram-negative bacteria reduced the maximum biofilm population of L. monocytogenes in dual species biofilms and increased its inactivation during desiccation. However, due to the higher desiccation resistance of Listeria relative to P. fluorescens and S. baltica, the pathogen survived in greater final numbers. In contrast, S. proteamaculans outcompeted the pathogen during the biofilm formation and exhibited similar desiccation survival, causing the N21 days of Serratia to be ca 3 Log10(CFU cm(-2)) greater than that of Listeria in the dual species biofilm. Microscopy revealed biofilm morphologies with variable amounts of exopolymeric substance and the presence of separate microcolonies. Under these simulated food plant conditions, the fate of L. monocytogenes during formation of mixed biofilms and desiccation depended on the implicit characteristics of the co-cultured bacterium.

  19. Characterization of the CrbS/R Two-Component System in Pseudomonas fluorescens Reveals a New Set of Genes under Its Control and a DNA Motif Required for CrbR-Mediated Transcriptional Activation

    Directory of Open Access Journals (Sweden)

    Edgardo Sepulveda

    2017-11-01

    Full Text Available The CrbS/R system is a two-component signal transduction system that regulates acetate utilization in Vibrio cholerae, P. aeruginosa, and P. entomophila. CrbS is a hybrid histidine kinase that belongs to a recently identified family, in which the signaling domain is fused to an SLC5 solute symporter domain through aSTAC domain. Upon activation by CrbS, CrbR activates transcription of the acs gene, which encodes an acetyl-CoA synthase (ACS, and the actP gene, which encodes an acetate/solute symporter. In this work, we characterized the CrbS/R system in Pseudomonas fluorescens SBW25. Through the quantitative proteome analysis of different mutants, we were able to identify a new set of genes under its control, which play an important role during growth on acetate. These results led us to the identification of a conserved DNA motif in the putative promoter region of acetate-utilization genes in the Gammaproteobacteria that is essential for the CrbR-mediated transcriptional activation of genes under acetate-utilizing conditions. Finally, we took advantage of the existence of a second SLC5-containing two-component signal transduction system in P. fluorescens, CbrA/B, to demonstrate that the activation of the response regulator by the histidine kinase is not dependent on substrate transport through the SLC5 domain.

  20. Quantification of Pseudomonas fluorescens strains F113, CHA0 and Pf153 in the rhizosphere of maize by strain-specific real-time PCR unaffected by the variability of DNA extraction efficiency.

    Science.gov (United States)

    Von Felten, Andreas; Défago, Geneviève; Maurhofer, Monika

    2010-05-01

    Pseudomonas fluorescens strains F113 and CHA0 are well-known plant growth-promoting rhizobacteria (PGPR) often used as model strains in biocontrol experiments. To monitor their persistence in large scale field experiments, culture-independent methods are needed. In this study, a strain-specific real-time PCR quantification tool was developed based on sequence-characterized amplified regions (SCAR) for P. fluorescens strains F113, CHA0 and Pf153. Differences in DNA extraction efficiencies from rhizosphere samples were circumvented using plasmid APA9 as internal standard to normalize C(T) values after real-time amplification. The detection limits of the real-time PCR assays for all three strains were approximately 10 cells for genomic DNA and 10(4)cells/g rhizosphere for maize samples grown in different natural soils. Population sizes of the three strains in the rhizosphere of maize measured by the new real-time PCR approaches were similar to those measured by most probable number (MPN)-PCR. A persistence study of the three strains indicated that the strains persisted differently over a period of 5weeks. In conclusion the newly developed real-time PCR approach is a fast and resource efficient method for monitoring individual biocontrol strains in natural soil, which makes it an apt quantification tool for future large-scale field experiments. Copyright 2010 Elsevier B.V. All rights reserved.

  1. Plasmid profilling and similarities in identities of probable microbes isolated from crude oil contaminated agricultural soil

    Directory of Open Access Journals (Sweden)

    Toochukwu Ekwutosi OGBULIE

    2013-05-01

    Full Text Available Plasmid analysis of bacteria isolated from agricultural soil experimentally contaminated with crude oil was carried out and the resultant bands’ depicting the different molecular sizes of the plasmid DNA molecules per isolate was obtained. There was no visible band observed for Klebsiella indicating that the organism lack plasmid DNA that confers degradative ability to it, possibly the gene could be borne on the chromosomal DNA which enabled its persistence in the polluted soil. Molecular characterization was undertaken to confirm the identities of the possible microorganisms that may be present in crude oil-contaminated soil. The result of the DNA extracted and amplified in a PCR using EcoRI and EcoRV restriction enzymes for cutting the DNA of the bacterial cells indicated no visible band for cuts made with EcoRV restriction enzyme showing that the enzyme is not specific for bacterial DNA of isolates in the samples, hence there was no amplification. By contrast though, visible bands of amplicons were observed using EcoRI restriction enzymes. The resultant visible bands of microbial profile obtained using the universal RAPD primer with nucleotide sequence of 5’—CTC AAA GCA TCT AGG TCC A---3’ showed that only Pseudomonas fluorescens and Bacillus mycoides had visible bands at identical position on the gel indicating that both species possibly had identical sequence or genes of negligible differences coding for degradation of hydrocarbons as shown by similar values in molecular weight and positions in the gel electrophoresis field.

  2. Isolated electrons

    Energy Technology Data Exchange (ETDEWEB)

    Ekstrom, Ph.; Winwland, D.

    1981-08-01

    The problem of electron g-factor measurement by means of an isolated electron is considered. The technique of the experiment performed at the Washington university is described. A single electron is enclosed in a homogeneous magnetic field which is superimposed by an electric field. The electric field configuration represents a Penning trap. The trap together with the enclosed electron forms an ''atom'' of macroscopic dimensions. The electron trajectory in the trap consists of three components. The electron quickly rotates over small loops (cyclotron motion), the centre of these loops slowly moves over a large circle (magistron motion). Meanwhile the electron oscillates back and forth along the trap axis. The electron motion in the atom field is quantized and the transitions between various types of motions correspond to definite radiation frequencies. At the anomal frequency the transition with spin flip is registered and the electron g-factor is measured. The value g=2.0023193044 is obtained with a probable error less than a unit of the last decimal digit.

  3. The interplay of StyR and IHF regulates substrate-dependent induction and carbon catabolite repression of styrene catabolism genes in Pseudomonas fluorescens ST

    Directory of Open Access Journals (Sweden)

    Leoni Livia

    2008-06-01

    Full Text Available Abstract Background In Pseudomonas fluorescens ST, the promoter of the styrene catabolic operon, PstyA, is induced by styrene and is subject to catabolite repression. PstyA regulation relies on the StyS/StyR two-component system and on the IHF global regulator. The phosphorylated response regulator StyR (StyR-P activates PstyA in inducing conditions when it binds to the high-affinity site STY2, located about -40 bp from the transcription start point. A cis-acting element upstream of STY2, named URE, contains a low-affinity StyR-P binding site (STY1, overlapping the IHF binding site. Deletion of the URE led to a decrease of promoter activity in inducing conditions and to a partial release of catabolite repression. This study was undertaken to assess the relative role played by IHF and StyR-P on the URE, and to clarify if PstyA catabolite repression could rely on the interplay of these regulators. Results StyR-P and IHF compete for binding to the URE region. PstyA full activity in inducing conditions is achieved when StyR-P and IHF bind to site STY2 and to the URE, respectively. Under catabolite repression conditions, StyR-P binds the STY1 site, replacing IHF at the URE region. StyR-P bound to both STY1 and STY2 sites oligomerizes, likely promoting the formation of a DNA loop that closes the promoter in a repressed conformation. We found that StyR and IHF protein levels did not change in catabolite repression conditions, implying that PstyA repression is achieved through an increase in the StyR-P/StyR ratio. Conclusion We propose a model according to which the activity of the PstyA promoter is determined by conformational changes. An open conformation is operative in inducing conditions when StyR-P is bound to STY2 site and IHF to the URE. Under catabolite repression conditions StyR-P cellular levels would increase, displacing IHF from the URE and closing the promoter in a repressed conformation. The balance between the open and the closed

  4. Efficacy of spray –Dried Pseudomonas fluorescens, strain CL145A (Zequanox®), for controlling Zebra Mussels (Dreissena polymorpha) within Lake Minnetonka, MN enclosures

    Science.gov (United States)

    Luoma, James A.; Severson, Todd J.

    2016-01-01

    The efficacy of whole water column and subsurface applications of the biopesticide Zequanox®, a commercially prepared spray-dried powder formulation of Pseudomonas fluorescens (strain CL145A), were evaluated for controlling zebra mussels (Dreissena polymorpha) within 27-m2 enclosures in Lake Minnetonka (Deephaven, Minnesota). Five treatments consisting of (1) two whole water column Zequanox applications, (2) two subsurface Zequanox applications, and (3) an untreated control were completed on each of three independent treatment days during September 2014. The two types of samplers used in the study were (1) type 1 samplers, which were custom built multi-plate samplers (wood, perforated aluminum, and tile substrates) that were placed into Robinson’s Bay in June of 2013 to allow for natural colonization by zebra mussels, and (2) type 2 samplers, which consisted of zebra mussels adhering to perforated aluminum trays that were placed into mesh containment bags. One day prior to treatment, three individual samplers of each type were distributed to test enclosures and exposed to a randomly assigned treatment. Sampling to determine the zebra mussel biomass adhering to type 1 samplers and the survival assessments for zebra mussels contained in type 2 samplers were completed ~40 days after exposure. The zebra mussel biomass adhering to type 1 samplers and the survival of zebra mussels contained in type 2 samplers were significantly less in groups treated with the highest Zequanox concentrations and in groups that received whole water column applications than comparable groups treated with lower Zequanox concentrations and subsurface applications. However, standardization of biomass and survival results to the amount of Zequanox applied showed that the lower concentrations and subsurface applications were more cost efficient, with respect to product used, at reducing zebra mussel biomass and for inducing zebra mussel mortality. Although the subsurface application methods

  5. Isolation and Identification of Sodium Fluoroacetate Degrading Bacteria from Caprine Rumen in Brazil

    Directory of Open Access Journals (Sweden)

    Expedito K. A. Camboim

    2012-01-01

    Full Text Available The objective of this paper was to report the isolation of two fluoroacetate degrading bacteria from the rumen of goats. The animals were adult goats, males, crossbred, with rumen fistula, fed with hay, and native pasture. The rumen fluid was obtained through the rumen fistula and immediately was inoculated 100 μL in mineral medium added with 20 mmol L−1 sodium fluoroacetate (SF, incubated at 39°C in an orbital shaker. Pseudomonas fluorescens (strain DSM 8341 was used as positive control for fluoroacetate dehalogenase activity. Two isolates were identified by 16S rRNA gene sequencing as Pigmentiphaga kullae (ECPB08 and Ancylobacter dichloromethanicus (ECPB09. These bacteria degraded sodium fluoroacetate, releasing 20 mmol L−1 of fluoride ion after 32 hours of incubation in Brunner medium containing 20 mmol L−1 of SF. There are no previous reports of fluoroacetate dehalogenase activity for P. kullae and A. dichloromethanicus. Control measures to prevent plant intoxication, including use of fences, herbicides, or other methods of eliminating poisonous plants, have been unsuccessful to avoid poisoning by fluoroacetate containing plants in Brazil. In this way, P. kullae and A. dichloromethanicus may be used to colonize the rumen of susceptible animals to avoid intoxication by fluoroacetate containing plants.

  6. Isolation and Identification of Sodium Fluoroacetate Degrading Bacteria from Caprine Rumen in Brazil

    Science.gov (United States)

    Camboim, Expedito K. A.; Almeida, Arthur P.; Tadra-Sfeir, Michelle Z.; Junior, Felício G.; Andrade, Paulo P.; McSweeney, Chris S.; Melo, Marcia A.; Riet-Correa, Franklin

    2012-01-01

    The objective of this paper was to report the isolation of two fluoroacetate degrading bacteria from the rumen of goats. The animals were adult goats, males, crossbred, with rumen fistula, fed with hay, and native pasture. The rumen fluid was obtained through the rumen fistula and immediately was inoculated 100 μL in mineral medium added with 20 mmol L−1 sodium fluoroacetate (SF), incubated at 39°C in an orbital shaker. Pseudomonas fluorescens (strain DSM 8341) was used as positive control for fluoroacetate dehalogenase activity. Two isolates were identified by 16S rRNA gene sequencing as Pigmentiphaga kullae (ECPB08) and Ancylobacter dichloromethanicus (ECPB09). These bacteria degraded sodium fluoroacetate, releasing 20 mmol L−1 of fluoride ion after 32 hours of incubation in Brunner medium containing 20 mmol L−1 of SF. There are no previous reports of fluoroacetate dehalogenase activity for P. kullae and A. dichloromethanicus. Control measures to prevent plant intoxication, including use of fences, herbicides, or other methods of eliminating poisonous plants, have been unsuccessful to avoid poisoning by fluoroacetate containing plants in Brazil. In this way, P. kullae and A. dichloromethanicus may be used to colonize the rumen of susceptible animals to avoid intoxication by fluoroacetate containing plants. PMID:22919294

  7. Non-target effects of the microbial control agents Pseudomonas fluorescens DR54 and Clonostachys rosea IK726 in soils cropped with barley followed by sugar beet: a greenhouse assessment

    DEFF Research Database (Denmark)

    Johansen, A.; Knudsen, I. M. B.; Binnerup, S. J.

    2005-01-01

    on plant growth or soil microorganisms. Phospholipid fatty acid (PLFA) analysis detected the perturbations of the soil microbial community structure in the MCA treatments as well as the return to non- perturbed conditions reflecting the decline of inoculant populations. The PLFA technique appears......Non-target effects of a bacterial (Pseudomonas fluorescens DR54) and a fungal (Clonostachys rosea IK726) microbial control agent (MCA), on the indigenous microbiota in bulk soil and rhizosphere of barley, and subsequent a sugar beet crop, were studied in a greenhouse experiment. MCAs were...... introduced by seed and soil inoculation. Bulk and rhizosphere soils were sampled regularly during the growth of barley and sugar beet. The soils were assayed for the fate of MCAs and various features of the indigenous soil microbiota. At the end of the experiment (193 d), DR54 and IK726 had declined...

  8. Modeling carbon dioxide effect in a controlled atmosphere and its interactions with temperature and pH on the growth of L. monocytogenes and P. fluorescens.

    Science.gov (United States)

    Couvert, Olivier; Guégan, Stéphanie; Hézard, Bernard; Huchet, Véronique; Lintz, Adrienne; Thuault, Dominique; Stahl, Valérie

    2017-12-01

    The effect of carbon dioxide, temperature, and pH on growth of Listeria monocytogenes and Pseudomonas fluorescens was studied, following a protocol to monitor microbial growth under a constant gas composition. In this way, the CO 2 dissolution didn't modify the partial pressures in the gas phase. Growth curves were acquired at different temperatures (8, 12, 22 and 37 °C), pH (5.5 and 7) and CO 2 concentration in the gas phase (0, 20, 40, 60, 80, 100% of the atmospheric pressure, and over 1 bar). These three factors greatly influenced the growth rate of L. monocytogenes and P. fluorescens, and significant interactions have been observed between the carbon dioxide and the temperature effects. Results showed no significant effect of the CO 2 concentration at 37 °C, which may be attributed to low CO2 solubility at high temperature. An inhibitory effect of CO 2 appeared at lower temperatures (8 and 12 °C). Regardless of the temperature, the gaseous CO 2 is sparingly soluble at acid pH. However, the CO 2 inhibition was not significantly different between pH 5.5 and pH 7. Considering the pKa of the carbonic acid, these results showed the dissolved carbon under HCO 3 - form didn't affect the bacterial inhibition. Finally, a global model was proposed to estimate the growth rate vs. CO 2 concentration in the aqueous phase. This dissolved concentration is calculated according to the physical equations related to the CO 2 equilibriums, involving temperature and pH interactions. This developed model is a new tool available to manage the food safety of MAP. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Effect of medicinal plants, Heavy metals and antibiotics against pathogenic bacteria isolated from raw, Boiled and pasteurized milk.

    Science.gov (United States)

    Ali, Nazish Mazhar; Sarwar, Khadija; Mazhar, Syed Abdullah; Liaqat, Iram; Andleeb, Saiqa; Mazhar, Bushra; Kalim, Bushra

    2017-11-01

    Present study has been undertaken to isolate and identify the bacterial flora in raw, boiled and pasteurized milk. Agar disc diffusion method was used to determine their sensitivity using medicinal plants, antibiotics and heavy metals. Methylene blue reduction test was used to test the quality of milk samples. Total 10 pathogenic strains were isolated, five strains were isolated from raw milk, three from boiled milk and 2 two from pasteurized milk. To determine optimum conditions for growth, these pathogenic microorganisms were incubated at various temperatures and pH. Gram's staining and biochemical tests revealed that these pathogenic bacteria include Lactobacillus sp., E. coli, Salmonella sp., Pseudomonas sp., Streptococcus sp. and Staphylococcus. Ribotyping revealed S2 as Pseudomonas fluorescens, S5 as Lactococcus lactis and S9 as Lactobacillus acidophilus. Prevalence of pathogenic organisms provided the evidence that contamination of milk arises during milking, transportation and storage of milk. Raw milk is more contaminated than other two types of milk because it contains highest percentage of pathogenic organisms and pasteurized milk was found to be of best quality among three types. So it is recommended to drink milk after proper boiling or pasteurization. Proper pasteurization and hygienic packing of milk is essential to minimize contamination in milk which can save human beings from many milk borne diseases. Our study suggests that antimicrobial use in animal husbandry should be minimized to reduce the hazard of antibiotic resistance. Plant extracts are better alternative against pathogenic bacteria in milk.

  10. Isolation and characterization of alkane degrading bacteria from petroleum reservoir waste water in Iran (Kerman and Tehran provenances).

    Science.gov (United States)

    Hassanshahian, Mehdi; Ahmadinejad, Mohammad; Tebyanian, Hamid; Kariminik, Ashraf

    2013-08-15

    Petroleum products spill and leakage have become two major environmental challenges in Iran. Sampling was performed in the petroleum reservoir waste water of Tehran and Kerman Provinces of Iran. Alkane degrading bacteria were isolated by enrichment in a Bushnel-Hass medium, with hexadecane as sole source of carbon and energy. The isolated strains were identified by amplification of 16S rDNA gene and sequencing. Specific primers were used for identification of alkane hydroxylase gene. Fifteen alkane degrading bacteria were isolated and 8 strains were selected as powerful degradative bacteria. These 8 strains relate to Rhodococcus jostii, Stenotrophomonas maltophilia, Achromobacter piechaudii, Tsukamurella tyrosinosolvens, Pseudomonas fluorescens, Rhodococcus erythropolis, Stenotrophomonas maltophilia, Pseudomonas aeruginosa genera. The optimum concentration of hexadecane that allowed high growth was 2.5%. Gas chromatography results show that all strains can degrade approximately half of hexadecane in one week of incubation. All of the strains have alkane hydroxylase gene which are important for biodegradation. As a result, this study indicates that there is a high diversity of degradative bacteria in petroleum reservoir waste water in Iran. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Isolate domination in graphs

    Directory of Open Access Journals (Sweden)

    I. Sahul Hamid

    2016-07-01

    Full Text Available A set D of vertices of a graph G is called a dominating set of G if every vertex in V(G−D is adjacent to a vertex in D. A dominating set S such that the subgraph 〈S〉 induced by S has at least one isolated vertex is called an isolate dominating set. An isolate dominating set none of whose proper subset is an isolate dominating set is a minimal isolate dominating set. The minimum and maximum cardinality of a minimal isolate dominating set are called the isolate domination number γ0 and the upper isolate domination number Γ0 respectively. In this paper we initiate a study on these parameters.

  12. Analog signal isolation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Beadle, E.R.

    1992-12-31

    This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application.

  13. Analog signal isolation techniques

    Energy Technology Data Exchange (ETDEWEB)

    Beadle, E.R.

    1992-01-01

    This paper discusses several techniques for isolating analog signals in an accelerator environment. The techniques presented here encompass isolation amplifiers, voltage-to-frequency converters (VIFCs), transformers, optocouplers, discrete fiber optics, and commercial fiber optic links. Included within the presentation of each method are the design issues that must be considered when selecting the isolation method for a specific application.

  14. Antimicrobial resistance of Pseudomonas spp. isolated from wastewater and wastewater-impacted marine coastal zone.

    Science.gov (United States)

    Luczkiewicz, Aneta; Kotlarska, Ewa; Artichowicz, Wojciech; Tarasewicz, Katarzyna; Fudala-Ksiazek, Sylwia

    2015-12-01

    In this study, species distribution and antimicrobial susceptibility of cultivated Pseudomonas spp. were studied in influent (INF), effluent (EFF), and marine outfall (MOut) of wastewater treatment plant (WWTP). The susceptibility was tested against 8 antimicrobial classes, active against Pseudomonas spp.: aminoglycosides, carbapenems, broad-spectrum cephalosporins from the 3rd and 4th generation, extended-spectrum penicillins, as well as their combination with the β-lactamase inhibitors, monobactams, fluoroquinolones, and polymyxins. Among identified species, resistance to all antimicrobials but colistin was shown by Pseudomonas putida, the predominant species in all sampling points. In other species, resistance was observed mainly against ceftazidime, ticarcillin, ticarcillin-clavulanate, and aztreonam, although some isolates of Pseudomonas aeruginosa, Pseudomonas fluorescens, Pseudomonas pseudoalcaligenes, and Pseudomonas protegens showed multidrug-resistance (MDR) phenotype. Among P. putida, resistance to β-lactams and to fluoroquinolones as well as multidrug resistance become more prevalent after wastewater treatment, but the resistance rate decreased in marine water samples. Obtained data, however, suggests that Pseudomonas spp. are equipped or are able to acquire a wide range of antibiotic resistance mechanisms, and thus should be monitored as possible source of resistance genes.

  15. Isolation of Bacteria with Antifungal Activity against the Phytopathogenic Fungi Stenocarpella maydis and Stenocarpella macrospora

    Directory of Open Access Journals (Sweden)

    Yuridia Mercado-Flores

    2011-08-01

    Full Text Available Stenocarpella maydis and Stenocarpella macrospora are the causal agents of ear rot in corn, which is one of the most destructive diseases in this crop worldwide. These fungi are important mycotoxin producers that cause different pathologies in farmed animals and represent an important risk for humans. In this work, 160 strains were isolated from soil of corn crops of which 10 showed antifungal activity against these phytopathogens, which, were identified as: Bacillus subtilis, Pseudomonas spp., Pseudomonas fluorescens, and Pantoea agglomerans by sequencing of 16S rRNA gene and the phylogenetic analysis. From cultures of each strain, extracellular filtrates were obtained and assayed to determine antifungal activity. The best filtrates were obtained in the stationary phase of B. subtilis cultures that were stable to the temperature and extreme pH values; in addition they did not show a cytotoxicity effect against brine shrimp and inhibited germination of conidia. The bacteria described in this work have the potential to be used in the control of white ear rot disease.

  16. Isolation and characterization of novel bacteria containing acc deaminase from the rhizosphere resource on dry-farming lands

    International Nuclear Information System (INIS)

    Zheng, P.; Tian, L.; Chen, F.; Cui, Z.

    2014-01-01

    Soil-microbe-plant interactions are known to be intricate and they can greatly influence the crop vigor and yield. Plant growth promoting rhizobacteria (PGPR) containing ACC deaminase can markedly affect plant metabolic processes under stress conditions. In the present study, we isolated 300 bacterial strains from the rhizosphere of maize or apple grown in drought-hit soil including four different locations of the Loess Plateau, China. Of all isolated strains, four with ACC deaminase activity (ranging from 28.88 to 155.12 nmol alpha-ketobutyrate mg-1 h-1) were further studied by determining their biological characters and sequencing the 16S rRNA gene. All four strains showed positive performance in terms of arabinose, citrate utilization, urease, indol, glucose and melibiose. In connection with the results of biochemical characters and phylogenetic analysis, these strains commonly belong to three different genera: Klebsiella, Pseudomonas and Raoultella and four different species: Klebsiella oxytoca, Klebsiella variicola, Pseudomonas fluorescens and Raoultella planticola. Although some researchers have reported their performance under stress conditions, we are the first to report Klebsiella oxytoca, Klebsiella variicola and Raoultella planticola containing ACC deaminase under drought stress. These findings are a reasonable explanation to their superb ability of causing stress-resistance in maize (Zea mays) or apple (Malus domestica) plants. The presence of diverse PGPR possessing potential ACC deaminase activity may be beneficial for enhancing crop production under different stress conditions. (author)

  17. Pseudomonas granadensis sp. nov., a new bacterial species isolated from the Tejeda, Almijara and Alhama Natural Park, Granada, Spain.

    Science.gov (United States)

    Pascual, Javier; García-López, Marina; Bills, Gerald F; Genilloud, Olga

    2015-02-01

    During the course of screening bacterial isolates as sources of as-yet unknown bioactive compounds with pharmaceutical applications, a chemo-organotrophic, Gram-negative bacterium was isolated from a soil sample taken from the Tejeda, Almijara and Alhama Natural Park, Granada, Spain. Strain F-278,770(T) was oxidase- and catalase-positive, aerobic, with a respiratory type of metabolism with oxygen as the terminal electron acceptor, non-spore-forming and motile by one polar flagellum, although some cells had two polar flagella. Phylogenetic analysis of the 16S rRNA, gyrB, rpoB and rpoD genes revealed that strain F-278,770(T) belongs to the Pseudomonas koreensis subgroup (Pseudomonas fluorescens lineage), with Pseudomonas moraviensis, P. koreensis, P. baetica and P. helmanticensis as its closest relatives. Chemotaxonomic traits such as polar lipid and fatty acid compositions and G+C content of genomic DNA corroborated the placement of strain F-278,770(T) in the genus Pseudomonas. DNA-DNA hybridization assays and phenotypic traits confirmed that this strain represents a novel species of the genus Pseudomonas, for which the name Pseudomonas granadensis sp. nov. is proposed. The type strain is F-278,770(T) ( = DSM 28040(T) = LMG 27940(T)). © 2015 Fundacion MEDINA, Centro de Excelencia en Investigacion de Medicamentos Innovadores en Andalucia.

  18. Utilization of Indigenous Microbial Isolates and their Mutants in the ...

    African Journals Online (AJOL)

    This study was designed to evaluate the ability of Pseudomonas fluorescens, Aspergillus fumigatus and Aspergillus niger to degrade cellulosic medical waste. Biodegradation was carried out in bioreactors and the ability to degrade or utilize cellulose was established on the basis of bacterial growth on cellulose medium ...

  19. Physics in isolation

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    In late May, about 330 physicists made their way up to isolated and beautiful Lake Louise high in the Canadian Rockies about 100 miles west of Calgary in a second effort to increase interactions between particle and nuclear physicists. The conference series aims to foster exciting and diverse physics by bringing the different physicists together somewhere which is so isolated that they must interact with each other. The formula worked very well and isolated Lake Louise was a huge success

  20. Mutations in the central cavity and periplasmic domain affect efflux activity of the resistance-nodulation-division pump EmhB from Pseudomonas fluorescens cLP6a.

    Science.gov (United States)

    Hearn, Elizabeth M; Gray, Murray R; Foght, Julia M

    2006-01-01

    The EmhABC efflux system in Pseudomonas fluorescens cLP6a is homologous to the multidrug and solvent efflux systems belonging to the resistance-nodulation-division (RND) family and is responsible for polycyclic aromatic hydrocarbon transport, antibiotic resistance, and toluene efflux. To gain a better understanding of substrate transport in RND efflux pumps, the EmhB pump was subjected to mutational analysis. Mutagenesis of amino acids within the central cavity of the predicted three-dimensional structure of EmhB showed selective activity towards antibiotic substrates. An A384P/A385Y double mutant showed increased susceptibility toward rhodamine 6G compared to the wild type, and F386A and N99A single mutants showed increased susceptibility to dequalinium compared to the wild type. As well, the carboxylic acid side chain of D101, located in the central cavity region, was found to be essential for polycyclic aromatic hydrocarbon transport and resistance to all antibiotic substrates of EmhB. Phenylalanine residues located within the periplasmic pore domain were also targeted for mutagenesis, and the F325A and F281A mutations significantly impaired efflux activity for all EmhB substrates. One mutation (A206S) in the outer membrane protein docking domain increased antibiotic resistance and toluene tolerance, demonstrating the important role of this domain in transport activity. These data demonstrate the roles of the central cavity and periplasmic domains in the function of the RND efflux pump EmhB.

  1. Isolated optic nerve pseudotumour

    International Nuclear Information System (INIS)

    Patankar, T.; Prasad, S.; Krishnan, A.; Laxminarayan, R.

    2000-01-01

    Isolated optic nerve involvement by the idiopathic inflammatory process is a rare finding and very few reports are available. Here a case of an isolated optic nerve inflammatory pseudotumour presenting with gradually progressive unilateral loss of vision is described. It showed dramatic response to a trial of steroids and its differential diagnoses are discussed. Copyright (1999) Blackwell Science Pty Ltd

  2. Isolated central vestibular syndrome.

    Science.gov (United States)

    Kim, Sung-Hee; Park, Seong-Ho; Kim, Hyo-Jung; Kim, Ji-Soo

    2015-04-01

    Isolated vestibular syndrome may occur all along the vestibular pathways from the peripheral labyrinth to the brain. By virtue of recent developments in clinical neurotology and neuroimaging, however, diagnosis of isolated central vestibulopathy is increasing. Here, we review five distinct syndromes of isolated central vestibular syndrome from lesions restricted to the vestibular nuclei, the nucleus prepositus hypoglossi, the flocculus, the tonsil, and the nodulus, and introduce a new vestibular syndrome from isolated involvement of the inferior cerebellar peduncle. Decreased responses to head impulses do not exclude a central lesion as a cause of isolated vestibular syndrome. Brain imaging, including diffusion-weighted magnetic resonance imaging (MRI), may be falsely negative during the acute phase in patients with isolated vestibular syndrome because of a stroke. Central signs should be sought carefully in patients with isolated vertigo, even when the patients show the features of peripheral vestibulopathy and negative MRIs. Recognition of these isolated central vestibular syndromes would aid in defining the lesions responsible for various vestibular manifestations in central vestibulopathy. © 2015 New York Academy of Sciences.

  3. Alternativ isolering i bygninger

    DEFF Research Database (Denmark)

    Andersen, T.; Skibstrup Eriksen, S.

    Denne SBI-meddelelse beskriver resultaterne af en undersøgelse af bygninger, hvor der er anvendt alternativ isolering. Undersøgelsen omfatter termografering og fugtmåling af udvendige bygningsdele isoleret med alternativ isolering. Endvidere rapporteres resultaterne af målinger af indholdet af tu...

  4. A Note on Isolate Domination

    OpenAIRE

    Sahul Hamid, Ismail; Balamurugan, S; Navaneethakrishnan, A

    2016-01-01

    A set $S$ of vertices of a graph $G$ such that $\\left\\langle S\\right\\rangle$ has an isolated vertex is called an \\emph{isolate set} of $G$. The minimum and maximum cardinality of a maximal isolate set are called the \\emph{isolate number} $i_0(G)$ and the \\emph{upper isolate number} $I_0(G)$ respectively. An isolate set that is also a dominating set (an irredundant set) is an $\\emph{isolate dominating set} \\ (\\emph{an isolate irredundant set})$. The \\emph{isolate domination number} $\\gamma_0(G...

  5. MOX Fabrication Isolation Considerations

    Energy Technology Data Exchange (ETDEWEB)

    Eric L. Shaber; Bradley J Schrader

    2005-08-01

    This document provides a technical position on the preferred level of isolation to fabricate demonstration quantities of mixed oxide transmutation fuels. The Advanced Fuel Cycle Initiative should design and construct automated glovebox fabrication lines for this purpose. This level of isolation adequately protects the health and safety of workers and the general public for all mixed oxide (and other transmutation fuel) manufacturing efforts while retaining flexibility, allowing parallel development and setup, and minimizing capital expense. The basis regulations, issues, and advantages/disadvantages of five potential forms of isolation are summarized here as justification for selection of the preferred technical position.

  6. Base isolation: Fresh insight

    Energy Technology Data Exchange (ETDEWEB)

    Shustov, V.

    1993-07-15

    The objective of the research is a further development of the engineering concept of seismic isolation. Neglecting the transient stage of seismic loading results in a widespread misjudgement: The force of resistance associated with velocity is mostly conceived as a source of damping vibrations, though it is an active force at the same time, during an earthquake type excitation. For very pliant systems such as base isolated structures with relatively low bearing stiffness and with artificially added heavy damping mechanism, the so called `damping`` force may occur even the main pushing force at an earthquake. Thus, one of the two basic pillars of the common seismic isolation philosophy, namely, the doctrine of usefulness and necessity of a strong damping mechanism, is turning out to be a self-deception, sometimes even jeopardizing the safety of structures and discrediting the very idea of seismic isolation. There is a way out: breaking with damping dependancy.

  7. Isolated sleep paralysis

    OpenAIRE

    Sawant, Neena S.; Parkar, Shubhangi R.; Tambe, Ravindra

    2005-01-01

    Sleep paralysis (SP) is a cardinal symptom of narcolepsy. However, little is available in the literature about isolated sleep paralysis. This report discusses the case of a patient with isolated sleep paralysis who progressed from mild to severe SP over 8 years. He also restarted drinking alcohol to be able to fall asleep and allay his anxiety symptoms. The patient was taught relaxation techniques and he showed complete remission of the symptoms of SP on follow up after 8 months.

  8. Evaluation of economically feasible, natural plant extract-based microbiological media for producing biomass of the dry rot biocontrol strain Pseudomonas fluorescens P22Y05 in liquid culture.

    Science.gov (United States)

    Khalil, Sadia; Ali, Tasneem Adam; Skory, Chris; Slininger, Patricia J; Schisler, David A

    2016-02-01

    The production of microbial biomass in liquid media often represents an indispensable step in the research and development of bacterial and fungal strains. Costs of commercially prepared nutrient media or purified media components, however, can represent a significant hurdle to conducting research in locations where obtaining these products is difficult. A less expensive option for providing components essential to microbial growth in liquid culture is the use of extracts of fresh or dried plant products obtained by using hot water extraction techniques. A total of 13 plant extract-based media were prepared from a variety of plant fruits, pods or seeds of plant species including Allium cepa (red onion bulb), Phaseolus vulgaris (green bean pods), and Lens culinaris (lentil seeds). In shake flask tests, cell production by potato dry rot antagonist Pseudomonas fluorescens P22Y05 in plant extract-based media was generally statistically indistinguishable from that in commercially produced tryptic soy broth and nutrient broth as measured by optical density and colony forming units/ml produced (P ≤ 0.05, Fisher's protected LSD). The efficacy of biomass produced in the best plant extract-based media or commercial media was equivalent in reducing Fusarium dry rot by 50-96% compared to controls. In studies using a high-throughput microbioreactor, logarithmic growth of P22Y05 in plant extract-based media initiated in 3-5 h in most cases but specific growth rate and the time of maximum OD varied as did the maximum pH obtained in media. Nutrient analysis of selected media before and after cell growth indicated that nitrogen in the form of NH4 accumulated in culture supernatants, possibly due to unbalanced growth conditions brought on by a scarcity of simple sugars in the media tested. The potential of plant extract-based media to economically produce biomass of microbes active in reducing plant disease is considerable and deserves further research.

  9. Complex regulation of AprA metalloprotease in Pseudomonas fluorescens M114: evidence for the involvement of iron, the ECF sigma factor, PbrA and pseudobactin M114 siderophore.

    Science.gov (United States)

    Maunsell, Bláithín; Adams, Claire; O'Gara, Fergal

    2006-01-01

    In the soil bacterium Pseudomonas fluorescens M114, extracellular proteolytic activity and fluorescent siderophore (pseudobactin M114) production were previously shown to be co-ordinately negatively regulated in response to environmental iron levels. An iron-starvation extracytoplasmic function sigma factor, PbrA, required for the transcription of siderophore biosynthetic genes, was also implicated in M114 protease regulation. The current study centred on the characterization and genetic regulation of the gene(s) responsible for protease production in M114. A serralysin-type metalloprotease gene, aprA, was identified and found to encode the major, if not only, extracellular protease produced by this strain. The expression of aprA and its protein product were found to be subject to complex regulation. Transcription analysis confirmed that PbrA was required for full aprA transcription under low iron conditions, while the ferric uptake regulator, Fur, was implicated in aprA repression under high iron conditions. Interestingly, the iron regulation of AprA was dependent on culture conditions, with PbrA-independent AprA-mediated proteolytic activity observed on skim milk agar supplemented with yeast extract, when supplied with iron or purified pseudobactin M114. These effects were not observed on skim milk agar without yeast extract. PbrA-independent aprA expression was also observed from a truncated transcriptional fusion when grown in sucrose asparagine tryptone broth supplied with iron or purified pseudobactin M114. Thus, experimental evidence suggested that iron mediated its effects via transcriptional activation by PbrA under low iron conditions, while an as-yet-unidentified sigma factor(s) may be required for the PbrA-independent aprA expression and AprA proteolytic activity induced by siderophore and iron.

  10. Antibiotic resistance and extended-spectrum β-lactamases in isolated bacteria from seawater of Algiers beaches (Algeria).

    Science.gov (United States)

    Alouache, Souhila; Kada, Mohamed; Messai, Yamina; Estepa, Vanesa; Torres, Carmen; Bakour, Rabah

    2012-01-01

    The aim of the study was to evaluate bacterial antibiotic resistance in seawater from four beaches in Algiers. The most significant resistance rates were observed for amoxicillin and ticarcillin, whereas they were relatively low for ceftazidime, cefotaxime and imipenem. According to sampling sites, the highest resistance rates were recorded for 2 sites subjected to chemical and microbiological inputs (amoxicillin, 43% and 52%; ticarcillin, 19.6% and 47.7%), and for 2 sites relatively preserved from anthropogenic influence, resistance rates were lowest (amoxicillin, 1.5% and 16%; ticarcillin, 0.8% and 2.6%). Thirty-four bacteria resistant to imipenem (n=14) or cefotaxime (n=20) were identified as Pseudomonas aeruginosa (n=15), Pseudomonas fluorescens (7), Stenotrophomonas maltophilia (4), Burkholderia cepacia (2), Bordetella sp. (1), Pantoea sp. (1), Acinetobacter baumannii (1), Chryseomonas luteola (1), Ochrobactrum anthropi (1) and Escherichia coli (1). Screening for extended spectrum β-lactamase showed the presence of CTX-M-15 β-lactamase in the E. coli isolate, and the encoding gene was transferable in association with the IncI1 plasmid of about 50 kbp. Insertion sequence ISEcp1B was located upstream of the CTX-M-15 gene. This work showed a significant level of resistance to antibiotics, mainly among environmental saprophytic bacteria. Transmissible CTX-M-15 was detected in E. coli; this may mean that contamination of the environment by resistant bacteria may cause the spread of resistance genes.

  11. Evaluation of gamma irradiation effect and Pseudomonas ...

    African Journals Online (AJOL)

    Antagonistic effect of Pseudomonas fluorescens and influence of gamma irradiation on the development of Penicillium expansum, the causal agent of postharvest disease on apple fruit was studied. P. fluorescens was originally isolated from rhizosphere of the apple trees. Suspension of P. fluorescens and P. expansum ...

  12. Characterization of a metal resistant Pseudomonas sp. isolated from uranium mine for its potential in heavy metal (Ni2+, Co2+, Cu2+, and Cd2+) sequestration.

    Science.gov (United States)

    Choudhary, Sangeeta; Sar, Pinaki

    2009-05-01

    Heavy metal sequestration by a multimetal resistant Pseudomonas strain isolated from a uranium mine was characterized for its potential application in metal bioremediation. 16S rRNA gene analysis revealed phylogenetic relatedness of this isolate to Pseudomonas fluorescens. Metal uptake by this bacterium was monophasic, fast saturating, concentration and pH dependent with maximum loading of 1048 nmol Ni(2+) followed by 845 nmol Co(2+), 828 nmol Cu(2+) and 700 nmol Cd(2+)mg(-1) dry wt. Preferential metal deposition in cell envelope was confirmed by TEM and cell fractionation. FTIR spectroscopy and EDX analysis revealed a major role of carboxyl and phosphoryl groups along with a possible ion exchange mechanism in cation binding. Binary system demonstrated selective metal binding affinity in the order of Cu(2+)>Ni(2+)>Co(2+)>Cd(2+). A comparison with similar metal uptake reports considering live bacteria strongly indicated the superiority of this strain in metal sequestration, which could be useful for developing efficient metal removal system.

  13. Isolated Optic Disc Tuberculosis

    Science.gov (United States)

    Mansour, Ahmad M.; Tabbara, Khalid F.; Tabbarah, Zuhair

    2015-01-01

    We present a healthy male subject who developed progressive visual loss in the left eye initially diagnosed as optic neuritis. Upon suspicion of infectious etiology, testing was positive for tuberculosis. There were no signs or symptoms of active systemic tuberculosis infection. The patient responded swiftly to antimycobacterial therapy with return of vision and resolution of disc swelling. Positive purified protein derivative skin test, negative chest radiograph, negative systemic workup, negative workup for other causes of unilateral optic neuritis and quick response to mycobacterial therapy reaffirm the entity of isolated optic disc tuberculosis similar to isolated choroidal tuberculosis without systemic manifestation. PMID:26483675

  14. Isolated Optic Disc Tuberculosis

    Directory of Open Access Journals (Sweden)

    Ahmad M. Mansour

    2015-09-01

    Full Text Available We present a healthy male subject who developed progressive visual loss in the left eye initially diagnosed as optic neuritis. Upon suspicion of infectious etiology, testing was positive for tuberculosis. There were no signs or symptoms of active systemic tuberculosis infection. The patient responded swiftly to antimycobacterial therapy with return of vision and resolution of disc swelling. Positive purified protein derivative skin test, negative chest radiograph, negative systemic workup, negative workup for other causes of unilateral optic neuritis and quick response to mycobacterial therapy reaffirm the entity of isolated optic disc tuberculosis similar to isolated choroidal tuberculosis without systemic manifestation.

  15. Isolated Fallopian Tube Torsion

    Directory of Open Access Journals (Sweden)

    S. Kardakis

    2013-01-01

    Full Text Available Isolated torsion of the Fallopian tube is a rare gynecological cause of acute lower abdominal pain, and diagnosis is difficult. There are no pathognomonic symptoms; clinical, imaging, or laboratory findings. A preoperative ultrasound showing tubular adnexal masses of heterogeneous echogenicity with cystic component is often present. Diagnosis can rarely be made before operation, and laparoscopy is necessary to establish the diagnosis. Unfortunately, surgery often is performed too late for tube conservation. Isolated Fallopian tube torsion should be suspected in case of acute pelvic pain, and prompt intervention is necessary.

  16. A note on isolate domination

    Directory of Open Access Journals (Sweden)

    Ismail Sahul Hamid

    2016-04-01

    Full Text Available A set $S$ of vertices of a graph $G$ such that $\\left\\langle S\\right\\rangle$ has an isolated vertex is called an \\emph{isolate set} of $G$. The minimum and maximum cardinality of a maximal isolate set are called the \\emph{isolate number} $i_0(G$ and the \\emph{upper isolate number} $I_0(G$ respectively. An isolate set that is also a dominating set (an irredundant set is an $\\emph{isolate dominating set} \\ (\\emph{an isolate irredundant set}$. The \\emph{isolate domination number} $\\gamma_0(G$ and the \\emph{upper isolate domination number} $\\Gamma_0(G$ are respectively the minimum and maximum cardinality of a minimal isolate dominating set while the \\emph{isolate irredundance number} $ir_0(G$ and the \\emph{upper isolate irredundance number} $IR_0(G$ are the minimum and maximum cardinality of a maximal isolate irredundant set of $G$. The notion of isolate domination was introduced in \\cite{sb} and the remaining were introduced in \\cite{isrn}. This paper further extends a study of these parameters.   

  17. Broadband Faraday Isolator

    OpenAIRE

    Berent, Michal; Rangelov, Andon A.; Vitanov, Nikolay V.

    2012-01-01

    Driving on an analogy with the technique of composite pulses in quantum physics, we propose a broadband Faraday rotator and thus a broadband optical isolator, which is composed of sequences of ordinary Faraday rotators and achromatic quarter-wave plates rotated at the predetermined angles.

  18. Islandscapes: isolation and pressure

    NARCIS (Netherlands)

    Renes, J.

    2014-01-01

    Islands are interesting subjects for study, with their frequent fluctuations in population size and economic activities, and their propensity for being at once both isolated fromand dependent on the outside world. They are often seen as metaphors-for human societies faced with environmental dangers

  19. A Matrix Isolation Infrared

    Indian Academy of Sciences (India)

    The elusive ≡C-H· · ·O complex in the hydrogen bonded systems of Phenylacetylene: A Matrix Isolation Infrared and Ab Initio Study ... A comparison of the spectral shifts observed in the features of PhAc-MeOH and PhAc-DEE would therefore independently confirm the existence or not of n-σ* complex in both these systems.

  20. Isolated fructose malabsorption.

    OpenAIRE

    Wales, J K; Primhak, R A; Rattenbury, J; Taylor, C J

    1990-01-01

    A patient with isolated fructose malabsorption presented with diarrhoea and colic during the first year of life and subsequently responded to a fructose free diet. Fructose malabsorption has been implicated in some cases of irritable bowel syndrome in adults and may also be an infrequently recognised cause of gastrointestinal symptoms in children.

  1. Isolated fructose malabsorption.

    Science.gov (United States)

    Wales, J K; Primhak, R A; Rattenbury, J; Taylor, C J

    1990-01-01

    A patient with isolated fructose malabsorption presented with diarrhoea and colic during the first year of life and subsequently responded to a fructose free diet. Fructose malabsorption has been implicated in some cases of irritable bowel syndrome in adults and may also be an infrequently recognised cause of gastrointestinal symptoms in children. PMID:2317071

  2. Isolated limb perfusion.

    Science.gov (United States)

    Gillespie, Rosalyn; Chantier, Nariane

    1994-12-08

    Growing concern over the rising incidence of malignant melanoma has brought about a need for information on this disorder and the treatment available. Isolated limb perfusion is a relatively new technique used in only a few hospitals. An increased knowledge base will lead to a better understanding of the nursing care required and to a more in-depth care plan.

  3. Emotion regulation during isolation

    Czech Academy of Sciences Publication Activity Database

    Poláčková Šolcová, Iva; Šolcová, Iva

    2012-01-01

    Roč. 47, Suppl. 1 (2012) ISSN 0020-7594. [International Congress of Psychology /30./. 22.07.2012-27.07.2012, Cape Town] R&D Projects: GA ČR(CZ) GAP407/11/2226 Institutional support: RVO:68081740 Keywords : emotion regulation * isolation * Mars500 Subject RIV: AN - Psychology

  4. ISOLATED MOLECULES IN METALS

    NARCIS (Netherlands)

    1992-01-01

    In this paper, some results obtained on the formation of isolated molecules of composition SnOx in silver and SnFx in copper-are reviewed. Hyperfine interaction and ion beam interaction techniques were used for the identification of these molecules.

  5. Broadband Faraday isolator.

    Science.gov (United States)

    Berent, Michał; Rangelov, Andon A; Vitanov, Nikolay V

    2013-01-01

    Driving on an analogy with the technique of composite pulses in quantum physics, we theoretically propose a broadband Faraday rotator and thus a broadband optical isolator, which is composed of sequences of ordinary Faraday rotators and achromatic quarter-wave plates rotated at the predetermined angles.

  6. Proteoglycan isolation and analysis

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    2001-01-01

    Proteoglycans can be difficult molecules to isolate and analyze due to large mass, charge, and tendency to aggregate or form macromolecular complexes. This unit describes detailed methods for purification of matrix, cell surface, and cytoskeleton-linked proteoglycans. Methods for analysis...

  7. Carbazole-degradative IncP-7 plasmid pCAR1.2 is structurally unstable in Pseudomonas fluorescens Pf0-1, which accumulates catechol, the intermediate of the carbazole degradation pathway.

    Science.gov (United States)

    Takahashi, Yurika; Shintani, Masaki; Li, Li; Yamane, Hisakazu; Nojiri, Hideaki

    2009-06-01

    We determined the effect of the host on the function and structure of the nearly identical IncP-7 carbazole-degradative plasmids pCAR1.1 and pCAR1.2. We constructed Pseudomonas aeruginosa PAO1(pCAR1.2) and P. fluorescens Pf0-1Km(pCAR1.2) and compared their growth on carbazole- and succinate-containing media with that of P. putida KT2440(pCAR1.1). We also assessed the stability of the genetic structures of the plasmids in each of the three hosts. Pf0-1Km(pCAR1.2) showed dramatically delayed growth when carbazole was supplied as the sole carbon source, while the three strains grew at nearly the same rate on succinate. Among the carbazole-grown Pf0-1Km(pCAR1.2) cells, two types of deficient strains appeared and dominated the population; such dominance was not observed in the other two strains or for succinate-grown Pf0-1Km(pCAR1.2). Genetic analysis showed that the two deficient strains possessed pCAR1.2 derivatives in which the carbazole-degradative car operon was deleted or its regulatory gene, antR, was deleted by homologous recombination between insertion sequences. From genomic information and quantitative reverse transcription-PCR analyses of the genes involved in carbazole mineralization by Pf0-1Km(pCAR1.2), we found that the cat genes on the chromosome of Pf0-1Km, which are necessary for the degradation of catechol (a toxic intermediate in the carbazole catabolic pathway), were not induced in the presence of carbazole. The resulting accumulation of catechol may have enabled the strain that lost its carbazole-degrading ability to have overall higher fitness than the wild-type strain. These results suggest that the functions of the chromosomal genes contributed to the selection of plasmid derivatives with altered structures.

  8. Isolation and identification of phytate-degrading rhizobacteria with activity of improving growth of poplar and Masson pine.

    Science.gov (United States)

    Li, Gui-E; Wu, Xiao-Qin; Ye, Jian-Ren; Hou, Liang; Zhou, Ai-Dong; Zhao, Liu

    2013-11-01

    A number of soil microorganisms can convert insoluble forms of phosphorus (P) to an accessible form to increase plant yields. Phytate is such a large kind of insoluble organic phosphorus that plants cannot absorb directly in soil, so the objectives of this study were to isolate, screen phytate-degrading rhizobacteria (PDRB), and to select potential microbial inocula that could increase the P uptake by plants. In this study, a total of 24 soil samples were collected from natural habitats of eight poplar and pine planting areas from the eastern to southern China. 17 PDRB strains were preliminarily screened from the rhizosphere soil of poplars and pines by the visible decolorization in the phytate selective medium. The highest ratio of the total diameter (colony + halo zone) to the colony diameter of the isolates was JZ-GX1, 3.85. Afterward, 17 PDRB strains were further determined for their abilities to degrade sodium phytate based on the amount of liberated inorganic P in liquid phytate specific medium. The results showed that the phytase ability of the three highest PDRB strains: JZ-GX1, JZ-DZ1 and JZ-ZJ1 were up to 2.58, 2.36 and 2.24 U/mL, respectively, much better than most of the bacteria reported in previous studies. In the soil-plant experiment, compared to CK, the best three strains of PDRB all could significantly promote growth of poplar and Masson pine under container growing. The three efficient PDRB strains were identified as follow: JZ-GX1, Rahnella aquatilis, both JZ-DZ1 and JZ-ZJ1 being autofluorescent, Pseudomonas fluorescens, by 16S rDNA gene sequencing technology, Biolog Identification System and biological characterization. The present study suggests that the three screened PDRB strains would have great potential application as biological fertilizers in the future.

  9. Bacillus odysseyi isolate

    Science.gov (United States)

    Venkateswaran, Kasthuri (Inventor); La Duc, Myron Thomas (Inventor)

    2007-01-01

    The present invention relates to discovery and isolation of a biologically pure culture of a Bacillus odysseyi isolate with high adherence and sterilization resistant properties. B. odysseyi is a round spore forming Bacillus species that produces an exosporium. This novel species has been characterized on the basis of phenotypic traits, 16S rDNA sequence analysis and DNA-DNA hybridization. According to the results of these analyses, this strain belongs to the genus Bacillus and the type strain is 34hs-1.sup.T (=ATCC PTA-4993.sup.T=NRRL B-30641.sup.T=NBRC 100172.sup.T). The GenBank accession number for the 16S rDNA sequence of strain 34hs-1.sup.T is AF526913.

  10. Isolated Inguinal Bladder Hernia

    OpenAIRE

    BAYSAL, Tamer; SOYLU, Ahmet; ERDOĞAN, Özgül

    2010-01-01

    Isolated urinary bladder herniation into the inguinal canal is rare. It is often diagnosed intraoperatively during surgery or is identified after intraoperative injury. Early diagnosis with radiologic imaging is important to avoid complications during repair surgery. Computed tomography seems the best imaging choice to outline the details of herniation. We report an incidentally discovered case of inguinal bladder herniation with intravenous pyelography and computed tomography findings. ...

  11. Mechanical beam isolator

    International Nuclear Information System (INIS)

    Post, R.F.; Vann, C.S.

    1996-10-01

    Back-reflections from a target, lenses, etc. can gain energy passing backwards through a laser just like the main beam gains energy passing forwards. Unless something blocks these back-reflections early in their path, they can seriously damage the laser. A Mechanical Beam Isolator is a device that blocks back-reflections early, relatively inexpensively, and without introducing aberrations to the laser beam

  12. Aircraft EMP Isolation Study.

    Science.gov (United States)

    1980-07-01

    technology are to be seen in the insulated column structures of modern Van de Graaff accelerators. These columns are plane assemblies of glass or...reviewed by the Public Affairs Office and is releasable to the National Technical Information Service (NTIS). At NTIS, it will be available to the general ...the aircraft tail and the high-energy, high-voltage impulse generator . 23 The recommended means of isolation consist of: (1) short dielectric columns on

  13. Isolated Coccygeal Tuberculosis

    OpenAIRE

    Kim, Do Un; Kim, Seok Won; Ju, Chang IL

    2012-01-01

    Isolated tuberculosis of the coccyx is extremely rare. A 35-year-old man presented with a 3-month history of coccygeal and gluteal pain. Computed tomography and magnetic resonance imaging revealed osseous destruction and a large enhancing mass involving the coccyx with anterior and posterior extension. Pathologic examination of the surgical specimen revealed necrosis, chronic granulomatous inflammation, and multinucleated giant cells consistent with tuberculosis. This case highlights the impo...

  14. Isolation, identification and molecular characterisation of an isolate ...

    African Journals Online (AJOL)

    Nucleotide sequence analysis of the partial coat protein gene of the ZYMV isolate from KZN revealed 95−98% sequence identity with isolates occurring in central Europe and the Indian subcontinent, and 90−93% identity with isolates from Singapore and Taiwan. These high levels of sequence identity indicate that the KZN ...

  15. Pseudomonas yamanorum sp. nov., a psychrotolerant bacterium isolated from a subantarctic environment.

    Science.gov (United States)

    Arnau, Víctor Gonzalo; Sánchez, Leandro Arturo; Delgado, Osvaldo Daniel

    2015-02-01

    A psychrotolerant strain, 8H1(T), was isolated from soil samples collected in Isla de los Estados, Ushuaia, Argentina. Cells were Gram-negative, aerobic, straight rods, occurring singly or in pairs, non-spore-forming and motile by means of two polar flagella. The isolate was able to grow in the range 4-35 °C, with optimum growth at 28 °C. The predominant cellular fatty acids were summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c), C16 : 0 and summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c). The polar lipid pattern of strain 8H1(T) comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and an unknown phospholipid. Ubiquinone 9 (Q-9) was the predominant lipoquinone. The DNA G+C content was 59.8 mol%. 16S rRNA gene sequence-based phylogeny suggested the affiliation of strain 8H1(T) to the 'Pseudomonas fluorescens group', displaying ≥98.5 % sequence similarity to 29 type strains. A multilocus sequence analysis (MLSA) study performed by concatenating 16S rRNA, gyrB, rpoD and rpoB gene sequences showed that isolate 8H1(T) could be discriminated from closely related species of the genus Pseudomonas and placed in the 'Pseudomonas gessardii subgroup', including the species with the highest MLSA sequence similarities: Pseudomonas brenneri (96.2 %), P. gessardii (96.1 %), P. proteolytica (96.0 %), P. meridiana (96.0 %) and P. mucidolens (95.4 %). DNA-DNA hybridization analysis between 8H1(T) and the type strains of these closely related species revealed relatedness values of 27.0, 8.8, 41.2, 39.7 and 46.1 %, respectively. These results, together with differences in several phenotypic features, support the classification of a novel species, for which the name Pseudomonas yamanorum sp. nov. is proposed. The type strain is 8H1(T) ( = DSM 26522(T) = CCUG 63249(T) = LMG 27247(T)). © 2015 IUMS.

  16. Miniature Optical Isolator, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — To address NASA's need for compact optical isolators, Physical Optics Corporation (POC) proposes to continue the development of a new Miniature Optical Isolator...

  17. Occurrence and antibiotic susceptibility of fish bacteria isolated from Oreochromis niloticus (Nile tilapia and Clarias gariepinus (African catfish in Uganda

    Directory of Open Access Journals (Sweden)

    S. P. Wamala

    2018-02-01

    Full Text Available Abstract The intention of this study was to identify the bacterial pathogens infecting Oreochromis niloticus (Nile tilapia and Clarias gariepinus (African catfish, and to establish the antibiotic susceptibility of fish bacteria in Uganda. A total of 288 fish samples from 40 fish farms (ponds, cages, and tanks and 8 wild water sites were aseptically collected and bacteria isolated from the head kidney, liver, brain and spleen. The isolates were identified by their morphological characteristics, conventional biochemical tests and Analytical Profile Index test kits. Antibiotic susceptibility of selected bacteria was determined by the Kirby-Bauer disc diffusion method. The following well-known fish pathogens were identified at a farm prevalence of; Aeromonas hydrophila (43.8%, Aeromonas sobria (20.8%, Edwardsiella tarda (8.3%, Flavobacterium spp. (4.2% and Streptococcus spp. (6.3%. Other bacteria with varying significance as fish pathogens were also identified including Plesiomonas shigelloides (25.0%, Chryseobacterium indoligenes (12.5%, Pseudomonas fluorescens (10.4%, Pseudomonas aeruginosa (4.2%, Pseudomonas stutzeri (2.1%, Vibrio cholerae (10.4%, Proteus spp. (6.3%, Citrobacter spp. (4.2%, Klebsiella spp. (4.2% Serratia marcescens (4.2%, Burkholderia cepacia (2.1%, Comamonas testosteroni (8.3% and Ralstonia picketti (2.1%. Aeromonas spp., Edwardsiella tarda and Streptococcus spp. were commonly isolated from diseased fish. Aeromonas spp. (n = 82 and Plesiomonas shigelloides (n = 73 were evaluated for antibiotic susceptibility. All isolates tested were susceptible to at-least ten (10 of the fourteen antibiotics evaluated. High levels of resistance were however expressed by all isolates to penicillin, oxacillin and ampicillin. This observed resistance is most probably intrinsic to those bacteria, suggesting minimal levels of acquired antibiotic resistance in fish bacteria from the study area. To our knowledge, this is the first study to

  18. Diabetes in population isolates

    DEFF Research Database (Denmark)

    Grarup, Niels; Moltke, Ida; Albrechtsen, Anders

    2015-01-01

    Type 2 diabetes (T2D) is an increasing health problem worldwide with particularly high occurrence in specific subpopulations and ancestry groups. The high prevalence of T2D is caused both by changes in lifestyle and genetic predisposition. A large number of studies have sought to identify...... on glucose-stimulated plasma glucose, serum insulin levels, and T2D. The variant defines a specific subtype of non-autoimmune diabetes characterized by decreased post-prandial glucose uptake and muscular insulin resistance. These and other recent findings in population isolates illustrate the value...

  19. Isolation of RNP granules

    DEFF Research Database (Denmark)

    Jønson, Lars; Nielsen, Finn Cilius; Christiansen, Jan

    2011-01-01

    The post-transcriptional operon provides a means of synexpression of mRNAs encoding interrelated proteins. The coordination of gene expression may be achieved by a trans-acting RNA-binding protein attaching to similar cis-elements in different, yet functionally clustered, mRNAs. The RNP granule can...... be regarded as a supramolecular assembly of RNA and protein, probably representing several overlapping post-transcriptional operons. The present protocol describes how RNP granules may be isolated by the transgenic expression of a 3X FLAG version of an RNA-binding protein under tetracycline control via...

  20. Waste isolation: a bibliography

    International Nuclear Information System (INIS)

    McLaren, L.H.

    1982-12-01

    This bibliography contains information on waste isolation included in the Department of Energy's Energy Data Base from Janurary 1981 through November 1982. The abstracts are grouped by subject category as shown in the table of contents. Entries in the subject index also facilitate access by subject, e.g., Radioactive Waste Disposal/Salt Deposits. Within each category the arrangement is by report number for reports, followed by nonreports in reverse chronological order. These citations are to research reports, journal articles, books, patents, theses, and conference papers from worldwide sources. Five indexes, each preceded by a brief description, are provided: Corporate Author, Personal Author, Subject, Contract Number, and Report Number

  1. Yeast Isolation for Bioethanol Production

    Directory of Open Access Journals (Sweden)

    EKA RURIANI

    2012-09-01

    Full Text Available We have isolated 12 yeast isolates from five different rotten fruits by using a yeast glucose chloramphenicol agar (YGCA medium supplemented with tetracycline. From pre-screening assay, four isolates exhibited higher substrate (glucose-xylose consumption efficiency in the reaction tube fermentation compared to Saccharomyces cerevisiae dan Saccharomyces ellipsoids as the reference strains. Based on the fermentation process in gooseneck flasks, we observed that two isolates (K and SB showed high fermentation efficiency both in sole glucose and mixed glucose-xylose substrate. Moreover, isolates K and SB produced relatively identical level of ethanol concentration compared to the reference strains. Isolates H and MP could only produce high levels of ethanol in glucose fermentation, while only half of that amount of ethanol was detected in glucose-xylose fermentation. Isolate K and SB were identified as Pichia kudriavzeevii (100% based on large sub unit (LSU ribosomal DNA D1/D2 region.

  2. Schizosaccharomyces isolation method

    Directory of Open Access Journals (Sweden)

    Benito Santiago

    2014-01-01

    Full Text Available This study discusses the optimization of a selective and differential medium which would facilitate the isolation of Schizosaccharomyces (a genus with a low incidence compared to other microorganisms to select individuals from this genus for industrial purposes, especially in light of the recent recommendation of the use of yeasts from this genus in the wine industry by the International Organisation of Vine and Wine, or to detect the presence of such yeasts, for those many authors who consider them food spoilers. To this end, we studied various selective differential agents based on the main physiological characteristics of these species, such as their high resistances to high concentrations of sugar, sulfur dioxide, sorbic acid, benzoic acid, acetic acid or malo ethanolic fermentation. This selective medium is based on the genus resistance to the antibiotic actidione and its high resistance to inhibitory agents such as benzoic acid. Malic acid was used as a differential factor due to the ability of this genus to metabolise it to ethanol, which allows detecting of the degradation of this compound. Lastly, the medium was successfully used to isolate strains of Schizosaccharomyces pombe from honey and honeycombs.

  3. Growth of Pseudomonas fluorescens on Cassava Starch ...

    African Journals Online (AJOL)

    Michael Horsfall

    al., 1998). The demand for the use of biopolymers involves their biodegradable and bio-compatible properties suitable for disposable products and their potential use as bio-materials for medical applications such as surgical sutures, long-term carriers for drugs, moulded plastics and films. (Holmes, 1985, Hahn et al., 1993).

  4. Characterization and identification of Pseudomonas fluorescens ...

    African Journals Online (AJOL)

    user

    2011-01-24

    Bangert et al., 1977; Bumpus and. Brock, 1988; Gregory, 1993). This dye has ... cetes and algae have been reported to degrade different pollutants (Bumpus and Brock, 1988; Leahy and Colwell,. 1990; Spain, 1995; Azmi et al., ...

  5. Element specific X-ray fluorescene microtomography

    OpenAIRE

    Günzler, Til Florian

    2003-01-01

    X-ray fluorescence is widely known as an element-specific scanning analytic tool. It is used in many fields of science and technology and has given major new insights into different problems. The relatively large penetration depth of x rays into matter makes them ideally suited for tomography. The combination of x-ray fluorescence analysis and scanning microtomography, hereafter called x-ray fluorescence microtomography, has been further developed and improved in this work. Employing the newl...

  6. Beyond insulation and isolation

    DEFF Research Database (Denmark)

    Højlund, Marie Koldkjær

    2016-01-01

    Most research on the acoustic environment in the modern Western hospital identifies raised noise levels as the main causal explanation for ranking noise as a critical stressor for patients, relatives and staff. Therefore, the most widely used strategies to tackle the problem in practice are insul......Most research on the acoustic environment in the modern Western hospital identifies raised noise levels as the main causal explanation for ranking noise as a critical stressor for patients, relatives and staff. Therefore, the most widely used strategies to tackle the problem in practice...... are insulation and isolation strategies to reduce measurable and perceptual noise levels. However, these strategies do not actively support the need to feel like an integral part of the shared hospital environment, which is a key element in creating healing environments, according to the paradigm of Evidence...

  7. Isolated Tracklet Linking

    Science.gov (United States)

    Weryk, Robert J.; Wainscoat, Richard J.; Williams, Gareth

    2017-10-01

    We discuss our on-going work to reduce the size of the Isolated Tracklet File (ITF) : a database hosted by the Minor Planet Center (MPC) containing 14+ million unlinked detections of asteroids. The ITF is dominated by observations from Pan-STARRS1 (F51), the Catalina Sky Survey (G96), and the Spacewatch Project (691).Survey telescopes are dependent on the follow-up capabilities of other telescopes, but many of their detected objects are not linked to already known objects, are are either not posted to the NEO Confirmation Page and/or are not followed up sufficiently, and therefore have their astrometry relegated to the ITF. While many of these asteroids may have in fact been previously observed sufficiently over longer timescales (enough to become designated objects), the linking of their astrometry can pose a challenge.We have developed a search method capable of finding and linking these isolated detections for distinct types of orbit classes, including main-belt and Hungaria objects (which often appear on the NEOCP due to their apparent motion). We use a brute-force technique which compares tracklets having motion which suggests they are the same object. Suspected linkages are further tested by searching for additional tracklets over multiple oppositions.So far, we have linked a significant portion of the ITF and have submitted these linkages to the MPC. We are confident in being able to link even more tracklets. Our method can even associate these new linkages with already designated objects, which will eventually lead to them becoming numbered objects. We hope to improve the efficiency of all asteroid surveys as future detections can be batch submitted without manual review, and more objects which are well known will not be posted to the NEOCP.

  8. Pseudomonads Isolated from Pristine Background Groundwater Proliferate More Effectively in Co-culture than in Monoculture Under Denitrifying Conditions

    Science.gov (United States)

    Aaring, A. B.; Lancaster, A.; Novichkov, P.; Adams, M. W. W.; Deutschbauer, A. M.; Chakraborty, R.

    2016-12-01

    As part of the Ecosystems and Networks Integrated with Genes and Molecular Assemblies (ENIGMA) consortium, we study the microbial community at the U.S. Department of Energy's Field Research Center (FRC) in Oak Ridge. The groundwater at this site contains plumes of nitrate with concentrations up to 14,000mg/L among other contaminants, though molybdenum concentrations are low. Because molybdenum is essential to nitrate reduction, this can be inhibitory to growth. Several strains of Pseudomonas were isolated from the same background groundwater sample. These isolates utilized diverse carbon sources ranging from acetate to glucose while growing under denitrifying conditions. The strains were also screened for nitrate tolerance and a couple of them were shown to be tolerant to 300-400 mM nitrate under anaerobic conditions. In the field site the bacteria live in consortia rather than in isolation, therefore we hypothesized that growth of these strains will be more robust in co-culture, as the denitrification pathway was segmented between the species. Three of the isolates (Pseudomonas fluorescens strains N1B4, N2E2, N2E3) were selected for in-depth analysis based on growth in pairwise co-cultures relative to monocultures, and the availability of the relevant genetic tools, such as transposon mutant libraries. Full genome sequencing showed that strain N2E3 has a truncated dentrification pathway: it lacks nitrous oxide reductase. Our results show strain N2E2 grow to maximum cell density an average of 45 hours more quickly when grown with strain N2E3 than in monoculture. Utilizing RB-TnSeq libraries of our strains, it was also found that some genes involved in nitrate reduction, sulfate permeability, molybdenum utilization, and anaerobic reduction are important for growth under these conditions. In addition, a few unexpected genes were also shown to be positively correlated to growth, such as genes homologous to genes for DNA proofreading or antibiotic production. These

  9. Isolation and synthesis of curcumin

    OpenAIRE

    Zetterström, Susanna

    2012-01-01

    The aim of this thesis was to evaluate pre-existing methods for isolation and synthesis of curcumin. Two different isolation methods were used, where only the extraction step differs from each other. To obtain pure curcumin, column chromatography was needed to separate the compound from its analogues. As for the isolation the synthesis was also carried out by two different methods, the first in a conventional way and the second one by using irradiation of microwaves. The result of the experim...

  10. Miniature Optical Isolator, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — To address NASA's need for miniature optical isolators in atom interferometry applications, Physical Optics Corporation (POC) proposes to develop a miniature optical...

  11. Acute unilateral isolated ptosis.

    Science.gov (United States)

    Court, Jennifer Helen; Janicek, David

    2015-01-05

    A 64-year-old man presented with a 2-day history of acute onset painless left ptosis. He had no other symptoms; importantly pupils were equal and reactive and eye movements were full. There was no palpable mass or swelling. He was systemically well with no headache, other focal neurological signs, or symptoms of fatigue. CT imaging showed swelling of the levator palpebrae superioris suggestive of myositis. After showing no improvement over 5 days the patient started oral prednisolone 30 mg reducing over 12 weeks. The ptosis resolved quickly and the patient remains symptom free at 6 months follow-up. Acute ptosis may indicate serious pathology. Differential diagnoses include a posterior communicating artery aneurysm causing a partial or complete third nerve palsy, Horner's syndrome, and myasthenia gravis. A careful history and examination must be taken. Orbital myositis typically involves the extraocular muscles causing pain and diplopia. Isolated levator myositis is rare. 2015 BMJ Publishing Group Ltd.

  12. METHICILLIN RESISTANCE IN STAPHYLOCOCCAL ISOLATES ...

    African Journals Online (AJOL)

    The study assessed the importance of Staphylococcus aureus as a urinary pathogen and the incidence of multidrug resistant (MDR), methicillin-resistant Staphylococcus aureus (MRSA). A total of 86 staphylococcal isolates made up of 50 clinical isolates from urine samples submitted to the Medical Microbiology Laboratory ...

  13. Isolated Amoebic Abscess of Spleen

    Directory of Open Access Journals (Sweden)

    Kaushik M

    2013-04-01

    Full Text Available Amoebic liver abscess is the most common extraintestinal manifestation of amoebiasis. Extrahepatic amoebic abscesses have occasionally been described in the lung, brain, and skin and presumably result from hematogenous spread. Isolated amoebic abscess of spleen has been reported scarcely in literature. We report here a case of isolated amoebic abscess of spleen.

  14. Dynamic isolation technologies in negative pressure isolation wards

    CERN Document Server

    Xu, Zhonglin

    2017-01-01

    This book presents novel design principles and technologies for dynamic isolation based on experimental studies. These approaches have now become the local standard in Beijing and are currently being promoted for use nationwide. Further, the book provides details of measures and guidelines for the design process. Departing from the traditional understanding that isolation wards should be designed with high negative pressure, airtight doors and fresh air, it establishes the basis for designing biological clean rooms, including isolation wards, using a simple and convenient scientific approach. This book is intended for designers, engineers, researchers, hospital management staff and graduate students in heating ventilation air conditioning (HVAC), air cleaning technologies and related areas.

  15. Browsing Isolated Population Data

    Directory of Open Access Journals (Sweden)

    Manias Teresa

    2005-12-01

    Full Text Available Abstract Background In our studies of genetically isolated populations in a remote mountain area in the center of Sardinia (Italy, we found that 80–85% of the inhabitants of each village belong to a single huge pedigree with families strictly connected to each other through hundreds of loops. Moreover, intermarriages between villages join pedigrees of different villages through links that make family trees even more complicated. Unfortunately, none of the commonly used pedigree drawing tools are able to draw the complete pedigree, whereas it is commonly accepted that the visual representation of families is very important as it helps researchers in identifying clusters of inherited traits and genotypes. We had a representation issue that compels researchers to work with subsets extracted from the overall genealogy, causing a serious loss of information on familiar relationships. To visually explore such complex pedigrees, we developed PedNavigator, a browser for genealogical databases properly suited for genetic studies. Results The PedNavigator is useful for genealogical research due to its capacity to represent family relations between persons and to make a visual verification of the links during family history reconstruction. As for genetic studies, it is helpful to follow propagation of a specific set of genetic markers (haplotype, or to select people for linkage analysis, showing relations between various branch of a family tree of affected subjects. Availability PedNavigator is an application integrated into a Framework designed to handle data for human genetic studies based on the Oracle platform. To allow the use of PedNavigator also to people not owning the same required informatics infrastructure or systems, we developed PedNavigator Lite with mainly the same features of the integrated one, based on MySQL database server. This version is free for academic users, and it is available for download from our site http://www.shardna.com.

  16. Characterization of a marine-isolated mercury-resistant Pseudomonas putida strain SP1 and its potential application in marine mercury reduction

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Weiwei; Chen, Lingxin; Liu, Dongyan [Chinese Academy of Sciences, Yantai, SD (China). Yantai Inst. of Coastal Zone Research (YICCAS); Chinese Academy of Sciences, Yantai, SD (China). Shandong Provincial Key Lab. of Coastal Zone Environmental Processes

    2012-02-15

    The Pseudomonas putida strain SP1 was isolated from marine environment and was found to be resistant to 280 {mu}M HgCl{sub 2}. SP1 was also highly resistant to other metals, including CdCl{sub 2}, CoCl{sub 2}, CrCl{sub 3}, CuCl{sub 2}, PbCl{sub 2}, and ZnSO{sub 4}, and the antibiotics ampicillin (Ap), kanamycin (Kn), chloramphenicol (Cm), and tetracycline (Tc). mer operon, possessed by most mercury-resistant bacteria, and other diverse types of resistant determinants were all located on the bacterial chromosome. Cold vapor atomic absorption spectrometry and a volatilization test indicated that the isolated P. putida SP1 was able to volatilize almost 100% of the total mercury it was exposed to and could potentially be used for bioremediation in marine environments. The optimal pH for the growth of P. putida SP1 in the presence of HgCl{sub 2} and the removal of HgCl{sub 2} by P. putida SP1 was between 8.0 and 9.0, whereas the optimal pH for the expression of merA, the mercuric reductase enzyme in mer operon that reduces reactive Hg{sup 2+} to volatile and relatively inert monoatomic Hg{sup 0} vapor, was around 5.0. LD50 of P. putida SP1 to flounder and turbot was 1.5 x 10{sup 9} CFU. Biofilm developed by P. putida SP1 was 1- to 3-fold lower than biofilm developed by an aquatic pathogen Pseudomonas fluorescens TSS. The results of this study indicate that P. putida SP1 is a low virulence strain that can potentially be applied in the bioremediation of HgCl{sub 2} contamination over a broad range of pH. (orig.)

  17. GOES-R Dual Isolation

    Science.gov (United States)

    Freesland, Doug; Carter, Delano; Chapel, Jim; Clapp, Brian; Howat, John; Krimchansky, Alexander

    2015-01-01

    The Geostationary Operational Environmental Satellite-R Series (GOES-R) is the first of the next generation geostationary weather satellites, scheduled for delivery in late 2015. GOES-R represents a quantum increase in Earth and solar weather observation capabilities, with 4 times the resolution, 5 times the observation rate, and 3 times the number of spectral bands for Earth observations. With the improved resolution, comes the instrument suite's increased sensitive to disturbances over a broad spectrum 0-512 Hz. Sources of disturbance include reaction wheels, thruster firings for station keeping and momentum management, gimbal motion, and internal instrument disturbances. To minimize the impact of these disturbances, the baseline design includes an Earth Pointed Platform (EPP), a stiff optical bench to which the two nadir pointed instruments are collocated together with the Guidance Navigation & Control (GN&C) star trackers and Inertial Measurement Units (IMUs). The EPP is passively isolated from the spacecraft bus with Honeywell D-Strut isolators providing attenuation for frequencies above approximately 5 Hz in all six degrees-of-freedom. A change in Reaction Wheel Assembly (RWA) vendors occurred very late in the program. To reduce the risk of RWA disturbances impacting performance, a secondary passive isolation system manufactured by Moog CSA Engineering was incorporated under each of the six 160 Nms RWAs, tuned to provide attenuation at frequencies above approximately 50 Hz. Integrated wheel and isolator testing was performed on a Kistler table at NASA Goddard Space Flight Center. High fidelity simulations were conducted to evaluate jitter performance for four topologies: 1) hard mounted no isolation, 2) EPP isolation only, 2) RWA isolation only, and 4) dual isolation. Simulation results demonstrate excellent performance relative to the pointing stability requirements, with dual isolated Line of Sight (LOS) jitter less than 1 micron rad.

  18. Patients experience of source isolation

    DEFF Research Database (Denmark)

    Johansen, Kamilla; Pedersen, Didde; Kragbak, Nina

    2014-01-01

    Patients´ experience of source isolation - a literature review Title: Patients experience of source isolation – a literature review Authors: Nina Kragbak*, Didde Pedersen*, Kamilla Johansen* and Peter E. Jensen** *students, **lecturer, bachelor in science and Ph.D., at VIA University College....... Physical environment: Some patients felt lonely and imprison, while other patients enjoyed time alone and not having to worry about other patients. A view to the life outside the physical boundaries of the isolation helped to avoid boredom. Importance of relatives: Relatives were a major source of comfort...

  19. Bacillus pumilus SAFR-032 isolate

    Science.gov (United States)

    Venkateswaran, Kasthuri J. (Inventor)

    2007-01-01

    The present invention relates to discovery and isolation of a biologically pure culture of a Bacillus pumilus SAFR-032 isolate with UV sterilization resistant properties. This novel strain has been characterized on the basis of phenotypic traits, 16S rDNA sequence analysis and DNA-DNA hybridization. According to the results of these analyses, this strain belongs to the genus Bacillus. The GenBank accession number for the 16S rDNA sequence of the Bacillus pumilus SAFR-032 isolate is AY167879.

  20. Waste Isolation Pilot Plant Overview

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, Douglas James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-27

    The mission of Waste Isolation Pilot Plant (WIPP) is to demonstrate the safe, environmentally sound, cost effective, permanent disposal of Transuranic (TRU) waste left from production of nuclear weapons.

  1. Isolation of microbial natural products.

    Science.gov (United States)

    Sterner, Olov

    2012-01-01

    In principle, the isolation of secondary metabolites from microbes does not differ from their isolation from other organisms. The extraction procedure may of course be quite different, especially if it is carried out in an industrial scale, but when an extract containing the metabolites of interest is at hand, it is the same palette of adsorbents and chromatographic techniques that provide the major tools for the fractionation and eventual isolation of the pure compounds. Compared to plants, in which one is sure to find secondary metabolites of certain types, e.g., flavonoids, microbes can be expected to produce virtually anything and it is important to go about the fractionation procedure with an open mind. This chapter presents an overview of preparation of extracts from microbial sources, and various methods and strategies involved in the isolation and characterization of microbial natural products.

  2. Seismic isolation in New Zealand

    International Nuclear Information System (INIS)

    Skinner, R.I.; Robinson, W.H.; McVerry, G.H.

    1989-01-01

    Bridges, buildings, and industrial equipment can be given increased protection from earthquake damage by limiting the earthquake attack through seismic isolation. A broad summary of the seismic responses of base-isolated structures is of considerable assistance for their preliminary design. Seismic isolation as already used in New Zealand consists of a flexible base or support combined with some form of energy-dissipating device, usually involving the hysteretic working of steel or lead. This paper presents examples of the New Zealand experience, where seismic isolation has been used for 42 bridges, 3 buildings, a tall chimney, and high-voltage capacitor banks. Additional seismic response factors, which may be important for nuclear power plants, are also discussed briefly

  3. Isolated Systolic Hypertension: A Health Concern?

    Science.gov (United States)

    Isolated systolic hypertension: A health concern? Is having a high top number (systolic) blood pressure, but a normal bottom number (diastolic) ... mm Hg, you have a common type of high blood pressure called isolated systolic hypertension. Isolated systolic hypertension can ...

  4. Market study: Biological isolation garment

    Science.gov (United States)

    1975-01-01

    The biological isolation garment was originally designed for Apollo astronauts to wear upon their return to earth from the moon to avoid the possibility of their contaminating the environment. The concept has been adapted for medical use to protect certain patients from environmental contamination and the risk of infection. The nature and size of the anticipated market are examined with certain findings and conclusions relative to clinical acceptability and potential commercial viability of the biological isolation garment.

  5. The Exosome Total Isolation Chip.

    Science.gov (United States)

    Liu, Fei; Vermesh, Ophir; Mani, Vigneshwaran; Ge, Tianjia J; Madsen, Steven J; Sabour, Andrew; Hsu, En-Chi; Gowrishankar, Gayatri; Kanada, Masamitsu; Jokerst, Jesse V; Sierra, Raymond G; Chang, Edwin; Lau, Kenneth; Sridhar, Kaushik; Bermudez, Abel; Pitteri, Sharon J; Stoyanova, Tanya; Sinclair, Robert; Nair, Viswam S; Gambhir, Sanjiv S; Demirci, Utkan

    2017-11-28

    Circulating tumor-derived extracellular vesicles (EVs) have emerged as a promising source for identifying cancer biomarkers for early cancer detection. However, the clinical utility of EVs has thus far been limited by the fact that most EV isolation methods are tedious, nonstandardized, and require bulky instrumentation such as ultracentrifugation (UC). Here, we report a size-based EV isolation tool called ExoTIC (exosome total isolation chip), which is simple, easy-to-use, modular, and facilitates high-yield and high-purity EV isolation from biofluids. ExoTIC achieves an EV yield ∼4-1000-fold higher than that with UC, and EV-derived protein and microRNA levels are well-correlated between the two methods. Moreover, we demonstrate that ExoTIC is a modular platform that can sort a heterogeneous population of cancer cell line EVs based on size. Further, we utilize ExoTIC to isolate EVs from cancer patient clinical samples, including plasma, urine, and lavage, demonstrating the device's broad applicability to cancers and other diseases. Finally, the ability of ExoTIC to efficiently isolate EVs from small sample volumes opens up avenues for preclinical studies in small animal tumor models and for point-of-care EV-based clinical testing from fingerprick quantities (10-100 μL) of blood.

  6. Isolation of Dermatophilus congolensis from a cat.

    Science.gov (United States)

    Kaya, O; Kirkan, S; Unal, B

    2000-03-01

    Dermatophilus congolensis was isolated from a cat with dermatitis. The isolate was sensitive to oxytetracyclin, streptomycin and penicillin but resistant to ampicillin, amoxicillin, gentamycin and cefoperazone.

  7. Geomorphology of Minnesota - Isolated Landform Structures

    Data.gov (United States)

    Minnesota Department of Natural Resources — Geomorphology of Minnesota - Isolated Landform Structures are essentially cartographic arcs representing isolated glacial features that were mapped in conjunction...

  8. Bovine papillomavirus isolation by ultracentrifugation.

    Science.gov (United States)

    Araldi, R P; Giovanni, D N S; Melo, T C; Diniz, N; Mazzuchelli-de-Souza, J; Sant'Ana, T A; Carvalho, R F; Beçak, W; Stocco, R C

    2014-11-01

    The bovine papillomavirus (BPV) is the etiological agent of bovine papillomatosis, which causes significant economic losses to livestock, characterized by the presence of papillomas that regress spontaneously or persist and progress to malignancy. Currently, there are 13 types of BPVs described in the literature as well as 32 putative new types. This study aimed to isolate viral particles of BPV from skin papillomas, using a novel viral isolation method. The virus types were previously identified with new primers designed. 77 cutaneous papilloma samples of 27 animals, Simmental breed, were surgically removed. The DNA was extracted and subjected to PCR using Delta-Epsilon and Xi primers. The bands were purified and sequenced. The sequences were analyzed using software and compared to the GenBank database, by BLAST tool. The viral typing showed a prevalence of BPV-2 in 81.81% of samples. It was also detected the presence of the putative new virus type BR/UEL2 in one sample. Virus isolation was performed by ultracentrifugation in a single density of cesium chloride. The method of virus isolation is less laborious than those previously described, allowing the isolation of complete virus particles of BPV-2. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Isolated Echinococcosis of cervical region

    Directory of Open Access Journals (Sweden)

    Pratima Khare

    2014-01-01

    Full Text Available Echinococcosis, commonly called as hydatid disease, is a parasitic infestation caused by the larva of the genus Echinococcus in human. Isolated occurrence of Echinococcosis without any evidence of visceral disease is very rare. A thorough search of the literature revealed only 11 cases of isolated cervical Echinococcosis. We report here a very rare case of isolated hydatid cyst in a 45-year-old female patient, who presented with swelling in right cervical region about 5 cm below the angle of mandible with no evidence of the disease elsewhere in the body. The case was diagnosed on fine needle aspiration cytology. The diagnosis was further supported by histopathology. We propose that the treating physician should also consider the differential diagnosis of Echinococcosis in the presence of an asymptomatic soft tissue mass, especially when the patient lives in an endemic area.

  10. Isolation, purification, characterization, and physiological behavior of ...

    African Journals Online (AJOL)

    The present work was devoted for isolation, characterization, and studying physiological behavior of drinking water borne pathogenic bacteria isolated from tap and cooling water. Total of 171 bacterial isolates were isolated from twenty nine different localities on eight common and specific agar media (Nutrient, Salmonella ...

  11. Isolation, characterization and identification of actinomycetes from ...

    African Journals Online (AJOL)

    A total of 62 isolates of actinomycetes were isolated from 7 soil samples collected from Agriculture Research Center Semongok, Sarawak. All 62 isolates exhibited a range of colony colours (dark grey, grey, dark brown, brownish, whitish and yellowish white). All the isolates were later purified and subjected to a few ...

  12. Completely Isolated? Health Information Seeking among Social Isolates

    Science.gov (United States)

    Askelson, Natoshia M.; Campo, Shelly; Carter, Knute D.

    2011-01-01

    To better target messages it is important to determine where people seek their health information. Interpersonal networks are a common way most people gather health information, but some people have limited networks. Using data from the 2004 General Social Survey (N = 984), we compared social isolates and nonisolates in their health…

  13. Isolation and screening of fungal isolates from bambara ( Vigna ...

    African Journals Online (AJOL)

    This study was carried out to isolate tannase producing fungal species using Bambara nuts as a substrate in a bid to finding alternatives to the importation of tannase. Fresh Bambara nuts were collected from different locations in Nigeria. They were cleaned, sorted and intermittently moistened with water to encourage fungal ...

  14. Spontaneous isolated celiac artery dissection

    Directory of Open Access Journals (Sweden)

    Tuba Cimilli Ozturk

    2011-01-01

    Full Text Available Dyspepsia with mild, stabbing epigastric discomfort without history of trauma is a very common symptom that emergency physicians see in their daily practice. Vascular emergencies, mostly the aortic dissection and aneurysm, are always described in the differential diagnosis with persistent symptoms. Isolated celiac artery dissection occurring spontaneously is a very rare diagnosis. The involvement of branch vessels is generally observed and patients show various clinical signs and symptoms according to the involved branch vessel. Here we are presenting a case with spontaneous isolated celiac artery dissection, without any branch vessel involvement or visceral damage, detected by computed tomography scans taken on admission.

  15. Isolated complete corpus callosal agenesis

    Directory of Open Access Journals (Sweden)

    Jaiganesh S, Venkateshwaran A, Naresh Kumar C, Rajasekhar KV

    2014-11-01

    Full Text Available Isolated complete corpus callosal agenesis is a rare entity. Usually this condition will be an associated finding in other syndromes. 3 month old male child came with complaints of deformed foot on both sides, not having a social smile and neck holding. Patient referred to the Radiology department for MRI brain which showed complete absence of corpus callosum, widely separated and parallely placed lateral ventricles, colpocephaly, high riding of 3rd ventricle and absence of cingulate gyrus and radial arrangement of gyri along the interhemispheric fissure. Hence it was reported as isolated complete corpus callosal agenesis and this article describes the Embryogenesis, anatomy, developmental anomalies and its clinical manifestations & prognosis.

  16. Isolation contactor state control system

    Energy Technology Data Exchange (ETDEWEB)

    Bissontz, Jay E.

    2017-05-16

    A controller area network (CAN) installed on a hybrid electric vehicle provides one node with control of high voltage power distribution system isolation contactors and the capacity to energize a secondary electro-mechanical relay device. The output of the secondary relay provides a redundant and persistent backup signal to the output of the node. The secondary relay is relatively immune to CAN message traffic interruptions and, as a result, the high voltage isolation contactor(s) are less likely to transition open in the event that the intelligent output driver should fail.

  17. Isolation and Cultivation of Anaerobes

    DEFF Research Database (Denmark)

    Aragao Börner, Rosa

    2016-01-01

    Anaerobic microorganisms play important roles in different biotechnological processes. Their complex metabolism and special cultivation requirements have led to less isolated representatives in comparison to their aerobic counterparts.In view of that, the isolation and cultivation of anaerobic...... microorganisms is still a promising venture, and conventional methodologies as well as considerations and modifications are presented here. An insight into new methodologies and devices as well as a discussion on future perspectives for the cultivation of anaerobes may open the prospects of the exploitation...... of these microorganisms as a source for biotechnology....

  18. Active Fault Isolation in MIMO Systems

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2014-01-01

    Active fault isolation of parametric faults in closed-loop MIMO system s are considered in this paper. The fault isolation consists of two steps. T he first step is group- wise fault isolation. Here, a group of faults is isolated from other pos sible faults in the system. The group-wise fault...... isolation is based directly on the input/output s ignals applied for the fault detection. It is guaranteed that the fault group includes the fault that had occurred in the system. The second step is individual fault isolation in the fault group . Both types of isolation are obtained by applying dedicated...

  19. Seismic isolation of nuclear power plants using sliding isolation bearings

    Science.gov (United States)

    Kumar, Manish

    Nuclear power plants (NPP) are designed for earthquake shaking with very long return periods. Seismic isolation is a viable strategy to protect NPPs from extreme earthquake shaking because it filters a significant fraction of earthquake input energy. This study addresses the seismic isolation of NPPs using sliding bearings, with a focus on the single concave Friction Pendulum(TM) (FP) bearing. Friction at the sliding surface of an FP bearing changes continuously during an earthquake as a function of sliding velocity, axial pressure and temperature at the sliding surface. The temperature at the sliding surface, in turn, is a function of the histories of coefficient of friction, sliding velocity and axial pressure, and the travel path of the slider. A simple model to describe the complex interdependence of the coefficient of friction, axial pressure, sliding velocity and temperature at the sliding surface is proposed, and then verified and validated. Seismic hazard for a seismically isolated nuclear power plant is defined in the United States using a uniform hazard response spectrum (UHRS) at mean annual frequencies of exceedance (MAFE) of 10-4 and 10 -5. A key design parameter is the clearance to the hard stop (CHS), which is influenced substantially by the definition of the seismic hazard. Four alternate representations of seismic hazard are studied, which incorporate different variabilities and uncertainties. Response-history analyses performed on single FP-bearing isolation systems using ground motions consistent with the four representations at the two shaking levels indicate that the CHS is influenced primarily by whether the observed difference between the two horizontal components of ground motions in a given set is accounted for. The UHRS at the MAFE of 10-4 is increased by a design factor (≥ 1) for conventional (fixed base) nuclear structure to achieve a target annual frequency of unacceptable performance. Risk oriented calculations are performed for

  20. Control biológico del marchitamiento vascular causado por Fusarium oxysporum f. sp. phaseoli en fríjol Phaseolus vulgaris L., mediante la acción combinada de Entrophospora colombiana, Trichoderma sp. Y Pseudomonas fluorescens

    Directory of Open Access Journals (Sweden)

    Avendaño Camila

    2006-06-01

    Hidden="false" UnhideWhenUsed="false" QFormat="true" Name="Intense Emphasis" /> Entrophospora colombiana, Trichoderma sp., Pseudomonas fluorescens y una combinación de estos antagonistas fueron evaluados como biocontroladores de Fusarium oxysporumf. sp. Phaseoli en plantas de fríjol de la variedad ‘ICA Tundama’. El ensayo se estableció en una casa de malla del Programa nacional de manejo integrado de plagas (MIP de la Corporación Colombiana de Investigación Agropecuaria (Corpoica, en el Centro de Investigación Tibaitat

  1. Isolated tricuspid valve infective endocarditis

    African Journals Online (AJOL)

    1990-07-07

    Jul 7, 1990 ... Case 2. Initial chest radiograph showing rounded shadows with cavitation. Fig. 2. Case 2. Chest radiograph showing progression to effusion. nuc/eacum was Isolated from repeated blood cultures. Two- dimensional echocardiography revealed vegetations on the tricuspid valve (Fig. 3). The patient was now ...

  2. Isolated tricuspid valve infective endocarditis

    African Journals Online (AJOL)

    1990-07-07

    Jul 7, 1990 ... A report of 6 cases. D. P. NAIDOO,. I. P. NAICKER,. S. NAICKER, S. VYTHYLlNGUM,. M. A. K. OMAR, A. S. MITHA. F. HASSEN,. Summary. Six cases of isolated tricuspid valve endocarditis in young women are described. Preceding ... friction rub, became hypotensive and died. At autopsy vegetations were ...

  3. JBS Haldane: an isolated souvenir

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Genetics; Volume 96; Issue 5. J. B. S. Haldane: an isolated souvenir. P. P. DIVAKARAN. HALDANE AT 125 Volume 96 Issue 5 November 2017 pp 733-733. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/jgen/096/05/0733-0733. Keywords.

  4. Physical isolation with virtual support

    DEFF Research Database (Denmark)

    Wearne, Susan M.; Teunissen, Pim W.; Dornan, Tim

    2015-01-01

    Purpose: Changing the current geographical maldistribution of the medical workforce is important for global health. Research regarding programs that train doctors for work with disadvantaged, rural populations is needed. This paper explores one approach of remote supervision of registrars in isol...

  5. Optical isolation by Faraday rotator

    International Nuclear Information System (INIS)

    Kasai, Takeshi; Matsushima, Isao; Nemoto, Fusashi; Yano, Masaaki

    1984-01-01

    Three Faraday rotators designed as optical isolators in a high power glass laser system are described. The spatial fluctuation of applied magnetic field is less than 1% throughout the Faraday glass rod. The Faraday rotators transmit more than 80% of the forward-going laser light and reject more than 96% of the backward-going light. (author)

  6. Vapor-barrier Vacuum Isolation System

    Science.gov (United States)

    Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)

    2014-01-01

    A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

  7. Contagem, isolamento e caracterização de bactérias psicrotróficas contaminantes de leite cru refrigerado Counting, isolation and characterization of psychrotrophic bacteria from refrigerated raw milk

    Directory of Open Access Journals (Sweden)

    Edna Froeder Arcuri

    2008-11-01

    Full Text Available Com os objetivos de quantificar, isolar e caracterizar bactérias psicrotróficas contaminantes de leite cru refrigerado, produzido na região da Zona da Mata de Minas Gerais e Sudeste do Rio de Janeiro, foram analisadas amostras de leite coletadas de 20 tanques coletivos e 23 tanques individuais. As contagens de bactérias psicrotróficas nas amostras de leite para os dois tipos de tanques de refrigeração variaram entre 10² e 10(7 Unidades Formadoras de Colônias (UFC ml-1, porém, um maior número de tanques coletivos apresentou contagens acima de 1 x 10(5 UFC ml-1. Foi verificada a predominância de bactérias psicrotróficas gram-negativas (81,2%, que foram identificadas pelos sistemas API 20E e API 20NE nos gêneros: Aeromonas, Alcaligenes, Acinetobacter, Burkholderia,Chryseomonas, Enterobacter, Ewingella, Klebsiella, Hafnia, Methylobacterium, Moraxella, Pantoea, Pseudomonas, Serratia, Sphingomonas e Yersinia. As bactérias gram-positivas (18,8% foram identificadas com API 50 CH, API Coryne e API Staph, nos gêneros: Bacillus, Brevibacterium, Cellum/Microbacterium, Kurthia e Staphylococcus. Os sistemas API utilizados não identificaram todos os isolados bacterianos. Pseudomonas foi o gênero mais isolado e P. fluorescens foi a espécie predominante. A maioria dos isolados bacterianos apresentou atividade proteolítica e/ou lipolítica a temperaturas de refrigeração de 4°C, 7°C e 10°C, evidenciando seu alto potencial de deterioração do leite e dos produtos lácteos. Os resultados ressaltam que maior atenção deve ser dada aos procedimentos que impeçam a contaminação do leite por esses microrganismos.This study aimed to quantify, isolate and characterize psychrotrophic bacteria from refrigerated raw milk produced at the ‘Mata’ Region of Minas Gerais State and Southeast of Rio de Janeiro State, Brazil. Raw milk samples, were collected at the farms, from 20 collective refrigerated tanks and 23 individual refrigerated tanks

  8. SYMBIODINIUM ISOLATES FROM STONY CORAL: ISOLATION, GROWTH CHARACTERISTICS AND EFFECTS OF UV IRRADIATION

    Science.gov (United States)

    Symbiodinium spp. Isolates from Stony Coral: Isolation, Growth Characteristics and Effects of UV Irradiation (Abstract). J. Phycol. 37(3):42-43.Symbiodinium species were isolated from Montipora capitata, Acropora palmata and two field samples of Porites porites. Cultures ...

  9. Isolated vasculitis of the CNS

    International Nuclear Information System (INIS)

    Block, F.; Reith, W.

    2000-01-01

    Vasculitis is a rare cause for disease of the CNS. The isolated vasculitis of the CNS is restricted to the CNS whereas other forms of vasculitis affect various organs including the CNS. Headache, encephalopathy, focal deficits and epileptic seizures are the major symptoms suggestive for vasculitis. One major criterion of the isolated vasculitis of the CNS is the lack of evidence for other vasculitis forms or for pathology of other organs. Angiography displays multifocal segmental stenosis of intracranial vessels. MRI demonstrates multiple lesions which in part show enhancement after gadolinium. A definite diagnosis can only be made on the grounds of biopsy from leptomeninges and parenchyma. Therapy consists of corticosteroids and cyclophosphamid. (orig.) [de

  10. Heterogeneity of koala retrovirus isolates.

    Science.gov (United States)

    Shimode, Sayumi; Nakagawa, So; Yoshikawa, Rokusuke; Shojima, Takayuki; Miyazawa, Takayuki

    2014-01-03

    Koala retrovirus (KoRV) is a gammaretrovirus which may induce immune suppression, leukemia and lymphoma in koalas. Currently three KoRV subgroups (A, B, and J) have been reported. Our phylogenetic analysis suggests that KoRV-B and KoRV-J should be classified as the same subgroup. In long terminal repeat (LTR), a KoRV-B isolate has four 17 bp tandem repeats named direct repeat (DR)-1, while a KoRV-J isolate (strain OJ-4) has three 37 bp tandem repeats named DR-2. We also found that the promoter activity of the KoRV-J strain OJ-4 is stronger than that of original KoRV-A, suggesting that KoRV-J may replicate more efficiently than KoRV-A. Copyright © 2013. Published by Elsevier B.V.

  11. Nuclei Isolation from Nematode Ascaris

    Science.gov (United States)

    Kang, Yuanyuan; Wang, Jianbin; Davis, Richard E.

    2017-01-01

    Preparing nuclei is necessary in a variety of experimental paradigms to study nuclear processes. In this protocol, we describe a method for rapid preparation of large number of relatively pure nuclei from Ascaris embryos or tissues that are ready to be used for further experiments such as chromatin isolation and ChIP-seq, nuclear RNA analyses, or preparation of nuclear extracts (Kang et al., 2016; Wang et al., 2016). PMID:29082294

  12. Isolated adrenal paracoccidioidomycosis: Case report

    International Nuclear Information System (INIS)

    Uribe Castro, Jorge Ricardo; Quintana, Humberto; Puentes, Alix Sofia and others

    2011-01-01

    Even though paracoccidioidomycosis has a relatively high prevalence in Latin America in a systemic form, isolated cases, especially compromising the adrenal glands, are uncommon, with only two reported cases. In this article, we report the case of a 55 year-old male with clinical manifestations of adrenal insufficiency. The only imaging finding was the presence of bilateral adrenal masses. The biopsy showed Paracoccidioides brasiliensis infection.

  13. Mycoplasma contamination of Chlamydia pneumoniae isolates

    DEFF Research Database (Denmark)

    Huniche, BS; Jensen, Lise Torp; Birkelund, Svend

    1998-01-01

    We examined 6 C. pneumonia isolates from The American Type Culture Collection (ATCC) and 2 Finnish isolates for Mycoplasma contamination. Three of the ATCC isolates and both of the Finnish isolates were Mycoplasma-contaminated. The contaminants were characterized by means of growth in BEa and BEg...... media, immunoblotting, polymerase chain reaction and pulsed field gel electrophoresis. Two of the 6 ATCC isolates [ATCC VR1355 (TWAR strain 2043) and ATCC VR1356 (TWAR strain 2023)] were infected with Mycoplasma hominis and 1 isolate [ATCC VR2282 (TWAR strain TW183)] was contaminated with both...... Mycoplasma hominis and Mycoplasma orale, whereas 3 of the ATCC isolates [ATCC VR1310, ATCC VR1360 (TWAR strain CM-1) and ATCC 53592 (TWAR strain AR39)] were not contaminated. The Finnish C. pneumoniae isolates Kajaani 6 and Parola were found to be contaminated with M. hominis and M. orale, respectively...

  14. Isolation of Malassezia furfur from a Cat

    Science.gov (United States)

    Crespo, M. J.; Abarca, M. L.; Cabañes, F. J.

    1999-01-01

    During a survey of the occurrence of Malassezia species in the external ear canals of cats without otitis externa, Malassezia furfur was isolated. This is the first report of the isolation of M. furfur from cats. PMID:10203525

  15. Isolation of Malassezia furfur from a Cat

    OpenAIRE

    Crespo, M. J.; Abarca, M. L.; Cabañes, F. J.

    1999-01-01

    During a survey of the occurrence of Malassezia species in the external ear canals of cats without otitis externa, Malassezia furfur was isolated. This is the first report of the isolation of M. furfur from cats.

  16. Isolation of haloorganic groundwater humic substances

    DEFF Research Database (Denmark)

    Krog, M.; Grøn, C.

    1995-01-01

    Humic substances were isolated from groundwater according to a revised method designed to avoid organohalogen artefacts. The prepared humic substances exhibited lower halogen contents than humic substances isolated according to the conventionally used method. Excessive oxidation or hydrolysis...

  17. Isolation of Antidiabetic Principle from Bougainvillea spectabilis ...

    African Journals Online (AJOL)

    rhamnopyranoside were isolated from the stem bark of B. spectabilis Willd. Conclusion: An antidiabetic principle, pinitol, was successfully isolated from the stem bark of B. spectabilis Willd. Keywords: Bougainvillea spectabilis, Column chromatography, ...

  18. [Selective Isolation of Rare Actinomycetes from Soil].

    Science.gov (United States)

    Sineva, O N; Terekhova, L P

    2015-01-01

    Many diverse methods for selective isolation of actinomycetes are used in discovery of organisms producing biologically active substances, as well as in ecological studies. Methods for isolation of rare actinomycetes from soil are reviewed.

  19. Behavioural reproductive isolation and speciation in Drosophila

    Indian Academy of Sciences (India)

    In the genus Drosophila, the phenomenon of behavioural reproductive isolation, which is an important type of premating (prezygotic) reproductive isolating mechanisms, has been extensively studied and interesting data have been documented. In many cases incomplete sexual isolation has been observed and the pattern ...

  20. (ESBLs) among clinical Enterobacteriaceae isolates obtained from ...

    African Journals Online (AJOL)

    One hundred Gram negative bacterial isolates were collected from a private diagnostic center and identified by subjecting the isolates to biochemical tests using standard procedures. Confirmed Enterobacteriaceae isolates were further subjected to screening for extended spectrum â-lactamases (ESBLs) production using ...

  1. Phenotypic and Genotypic Characterization of Nosocomial Isolates ...

    African Journals Online (AJOL)

    Purpose: To investigate the occurrence, species prevalence, antibacterial resistance, and molecular characteristics of S. aureus isolates from different wards located in a university hospital. Methods: A total of one hundred and fifty S. aureus isolates were recovered from various clinical specimens. The isolates were tested ...

  2. Isolation, characterization, and hydrolytic activities of Geobacillus ...

    African Journals Online (AJOL)

    The present study was conducted to isolate, identify, characterize and to determine the enzymatic activities of the thermophilic Geobacillus species from five Jordanian hot springs. Based on phenotypic characters, eight thermophilic isolates were identified and belonged to the genus Geobacillus. The Geobacillus isolates ...

  3. Isolation and morphological characterization of antibiotic producing ...

    African Journals Online (AJOL)

    Purpose: To isolate and characterize antibiotic producing actinomycetes from soil samples in Belgaum, Karnataka, India. Methods: Crowded plate technique was used for the isolation of actinomycetes in media such as soybean – casein digest medium and actinomycetes isolation agar. The morphological and cultural ...

  4. Fungi isolated in school buildings

    Directory of Open Access Journals (Sweden)

    Elżbieta Ejdys

    2013-12-01

    Full Text Available The aim of the study was to determine the species composition of fungi occurring on wall surfaces and in the air in school buildings. Fungi isolated from the air using the sedimentation method and from the walls using the surface swab technique constituted the study material. Types of finish materials on wall surfaces were identified and used in the analysis. Samples were collected in selected areas in two schools: classrooms, corridors, men's toilets and women's toilets, cloakrooms, sports changing rooms and shower. Examinations were conducted in May 2005 after the heating season was over. Fungi were incubated on Czapek-Dox medium at three parallel temperatures: 25, 37 and 40°C, for at least three weeks. A total of 379 isolates of fungi belonging to 32 genera of moulds, yeasts and yeast-like fungi were obtained from 321 samples in the school environment. The following genera were isolated most frequently: Aspergillus, Penicillium and Cladosporium. Of the 72 determined species, Cladosporium herbarum, Aspergillus fumigatus and Penicillium chrysogenum occurred most frequently in the school buildings. Wall surfaces were characterised by an increased prevalence of mycobiota in comparison with the air in the buildings, with a slightly greater species diversity. A certain species specificity for rough and smooth wall surfaces was demonstrated. Fungi of the genera Cladosporium and Emericella with large spores adhered better to smooth surfaces while those of the genus Aspergillus with smaller conidia adhered better to rough surfaces. The application of three incubation temperatures helped provide a fuller picture of the mycobiota in the school environment.

  5. Braking index of isolated pulsars

    Science.gov (United States)

    Hamil, O.; Stone, J. R.; Urbanec, M.; Urbancová, G.

    2015-03-01

    Isolated pulsars are rotating neutron stars with accurately measured angular velocities Ω , and their time derivatives that show unambiguously that the pulsars are slowing down. Although the exact mechanism of the spin-down is a question of detailed debate, the commonly accepted view is that it arises through emission of magnetic dipole radiation (MDR) from a rotating magnetized body. Other processes, including the emission of gravitational radiation, and of relativistic particles (pulsar wind), are also being considered. The calculated energy loss by a rotating pulsar with a constant moment of inertia is assumed proportional to a model dependent power of Ω . This relation leads to the power law Ω ˙ =-K Ωn where n is called the braking index. The MDR model predicts n exactly equal to 3. Selected observations of isolated pulsars provide rather precise values of n , individually accurate to a few percent or better, in the range 1 structure. In addition, we examine the effects of the baryonic mass MB of the star, and possible core superfluidity, on the value of the braking index within the MDR model. Four microscopic equations of state are employed as input to two different computational codes that solve Einstein's equations numerically, either exactly or using the perturbative Hartle-Thorne method, to calculate the moment of inertia and other macroscopic properties of rotating neutron stars. The calculations are performed for fixed values of MB (as masses of isolated pulsars are not known) ranging from 1.0 - 2.2 M⊙ , and fixed magnetic dipole moment and inclination angle between the rotational and magnetic field axes. The results are used to solve for the value of the braking index as a function of frequency, and find the effect of the choice of the EoS, MB. The density profile of a star with a given MB is calculated to determine the transition between the crust and the core and used in estimation of the effect of core superfluidity on the braking index. Our

  6. Phylogeography of Burkholderia pseudomallei Isolates, Western Hemisphere.

    Science.gov (United States)

    Gee, Jay E; Gulvik, Christopher A; Elrod, Mindy G; Batra, Dhwani; Rowe, Lori A; Sheth, Mili; Hoffmaster, Alex R

    2017-07-01

    The bacterium Burkholderia pseudomallei causes melioidosis, which is mainly associated with tropical areas. We analyzed single-nucleotide polymorphisms (SNPs) among genome sequences from isolates of B. pseudomallei that originated in the Western Hemisphere by comparing them with genome sequences of isolates that originated in the Eastern Hemisphere. Analysis indicated that isolates from the Western Hemisphere form a distinct clade, which supports the hypothesis that these isolates were derived from a constricted seeding event from Africa. Subclades have been resolved that are associated with specific regions within the Western Hemisphere and suggest that isolates might be correlated geographically with cases of melioidosis. One isolate associated with a former World War II prisoner of war was believed to represent illness 62 years after exposure in Southeast Asia. However, analysis suggested the isolate originated in Central or South America.

  7. Isolation of technogenic magnetic particles

    Energy Technology Data Exchange (ETDEWEB)

    Catinon, Mickaël, E-mail: mickael.catinon@gmail.com [Laboratoire LECA, UMR 5553, Equipe Pollution, Environnement, Ecotoxicologie et Ecoremédiation, Univ. J. Fourier, 38041 Grenoble (France); Ayrault, Sophie, E-mail: sophie.ayrault@lsce.ispl.fr [Laboratoire des Sciences du Climat et de l' Environnement, UMR 8212, CEA-CNRS-UVSQ/IPSL, 91198 Gif-sur-Yvette (France); Boudouma, Omar, E-mail: boudouma@ccr.jussieu.fr [Service du MEB, UFR928, Université Pierre et Marie Curie, 75252 Paris VI (France); Bordier, Louise, E-mail: Louise.Bordier@lsce.ipsl.fr [Laboratoire des Sciences du Climat et de l' Environnement, UMR 8212, CEA-CNRS-UVSQ/IPSL, 91198 Gif-sur-Yvette (France); Agnello, Gregory, E-mail: contact@evinrude.fr [Evinrude, Espace St Germain, 38200 Vienne (France); Reynaud, Stéphane, E-mail: stephane.reynaud@ujf-grenoble.fr [Laboratoire LECA, UMR 5553, Equipe Pollution, Environnement, Ecotoxicologie et Ecoremédiation, Univ. J. Fourier, 38041 Grenoble (France); Tissut, Michel, E-mail: michel.tissut@ujf-grenoble.fr [Laboratoire LECA, UMR 5553, Equipe Pollution, Environnement, Ecotoxicologie et Ecoremédiation, Univ. J. Fourier, 38041 Grenoble (France)

    2014-03-01

    Technogenic magnetic particles (TMPs) emitted by various industrial sources, such as smelting plants, end up after atmospheric transfer on the soil surface. In the present study, we characterised the origin and composition of such particles emitted by a large iron smelting plant and deposited on particular substrates, namely tombstones, which act as a very interesting and appropriate matrix when compared to soil, tree bark, lichens or attic dust. The isolation and subsequent description of TMPs require a critical step of separation between different components of the sample and the magnetic particles; here, we described an efficient protocol that fulfils such a requirement: it resorts to water suspension, sonication, repeated magnetic extraction, sedimentation, sieving and organic matter destruction at 550 °C in some instances. The isolated TMPs displayed a noticeable crystalline shape with variable compositions: a) pure iron oxides, b) iron + Cr, Ni or Zn, and c) a complex structure containing Ca, Si, Mg, and Mn. Using Scanning Electron Microscope Energy Dispersive X-ray (SEM–EDX), we obtained profiles of various and distinct magnetic particles, which allowed us to identify the source of the TMPs. - Highlights: • The developed method offers a low-cost approach of large-scale dry deposition. • Tombstones are excellent supports for sampling these atmospheric deposits. • Smelted elements crystallise after cooling, giving typical technogenic magnetic particles (TMPs). • Coupling microscopic and bulk analyses allows identifying TMP origin. • Magnetic TMPs issued from steel industry were separated by a new technique.

  8. Establishing the isolated Standard Model

    International Nuclear Information System (INIS)

    Wells, James D.; Zhang, Zhengkang; Zhao, Yue

    2017-02-01

    The goal of this article is to initiate a discussion on what it takes to claim ''there is no new physics at the weak scale,'' namely that the Standard Model (SM) is ''isolated.'' The lack of discovery of beyond the SM (BSM) physics suggests that this may be the case. But to truly establish this statement requires proving all ''connected'' BSM theories are false, which presents a significant challenge. We propose a general approach to quantitatively assess the current status and future prospects of establishing the isolated SM (ISM), which we give a reasonable definition of. We consider broad elements of BSM theories, and show many examples where current experimental results are not sufficient to verify the ISM. In some cases, there is a clear roadmap for the future experimental program, which we outline, while in other cases, further efforts - both theoretical and experimental - are needed in order to robustly claim the establishment of the ISM in the absence of new physics discoveries.

  9. From rumors to genetic isolates

    Directory of Open Access Journals (Sweden)

    Eduardo E. Castilla

    2014-01-01

    Full Text Available Here we propose a registration process for population genetic isolates, usually geographic clusters of genetic disorders, based on the systematic search of rumors, defined as any type of account regardless of its reliability. Systematically ascertained rumors are recorded, and validated through a progressive process of pre-established steps. This paper outlines the conceptual basis for this approach and presents the preliminary results from a rumor-based nationwide registry of genetically isolated populations, named CENISO (Censo Nacional de Isolados, operating in Brazil since 2009. During the first four years of its existence (2009-2013, a total of 191 Rumors were registered and validated, resulting in a prevalence rate of one per million inhabitants of Brazil. When the five statutory geographic regions of Brazil were considered, more Rumors were registered for the Northeast (2.11; 1.74-2.54 per 10(6 than for the remaining four regions, North, Center-West, Southeast, and South, which did not differ among themselves. About half (86/191 of the recorded rumors were proven to be geographic clusters; of these disorders, 58 were autosomal recessive, 17 autosomal dominant, 5 X-linked, 3 multifactorial, and one environmental (thalidomide embryopathy.

  10. Neisseria gonorrhoeae isolates from Ethiopia

    Science.gov (United States)

    Gedebou, Messele; Tassew, Alebachew

    1980-01-01

    The minimal inhibitory concentration (MIC) values of penicillin, ampicillin, tetracycline, chloramphenicol, and streptomycin for 500 gonococcal strains were studied for product-moment coefficient correlations. The strains were isolated from male patients with acute gonococcal urethritis attending the Venereal Disease Clinic in Addis Ababa. The MICs of all pairs except the ampicillin/streptomycin pair were positively correlated, with r = 0.20-0.53, Pstreptomycin pair was not correlated, r = 0.06, P>0.05. Despite the significant correlation between the susceptibilities of strains to penicillin and tetracycline, 85% of the penicillin-resistant strains were sensitive to tetracycline. However, 75.6% of tetracycline-resistant strains were also resistant to penicillin. Similar differences in percentages of resistance and susceptibility of strains also occurred between tetracycline and ampicillin as well as between tetracycline and streptomycin pairs, while pair correlations were also noted. No chloramphenicol-resistant strain was isolated. But correlations were found between the MIC values of chloramphenicol and those of the other 4 antibiotics. Forty-seven percent of the 500 strains were resistant to 2 or more antibiotics. One hundred and twenty-six strains (25.2%) were resistant to 2 antibiotics, about half of which were resistant to penicillin and ampicillin. Resistance to 3 antibiotics was shown in 18.6% of strains, the majority being resistant to penicillin, ampicillin, and streptomycin. Eighteen strains (3.6%) were resistant to 4 antibiotics, while no strain was found resistant to all 5 antibiotics. PMID:6769600

  11. Power inverter with optical isolation

    Science.gov (United States)

    Duncan, Paul G.; Schroeder, John Alan

    2005-12-06

    An optically isolated power electronic power conversion circuit that includes an input electrical power source, a heat pipe, a power electronic switch or plurality of interconnected power electronic switches, a mechanism for connecting the switch to the input power source, a mechanism for connecting comprising an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or input bus bars, an optically isolated drive circuit connected to the switch, a heat sink assembly upon which the power electronic switch or switches is mounted, an output load, a mechanism for connecting the switch to the output load, the mechanism for connecting including an interconnecting cable and/or bus bar or plurality of interconnecting cables and/or output bus bars, at least one a fiber optic temperature sensor mounted on the heat sink assembly, at least one fiber optic current sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic voltage sensor mounted on the load interconnection cable and/or output bus bar, at least one fiber optic current sensor mounted on the input power interconnection cable and/or input bus bar, and at least one fiber optic voltage sensor mounted on the input power interconnection cable and/or input bus bar.

  12. From rumors to genetic isolates

    Science.gov (United States)

    Castilla, Eduardo E.; Schuler-Faccini, Lavinia

    2014-01-01

    Here we propose a registration process for population genetic isolates, usually geographic clusters of genetic disorders, based on the systematic search of rumors, defined as any type of account regardless of its reliability. Systematically ascertained rumors are recorded, and validated through a progressive process of pre-established steps. This paper outlines the conceptual basis for this approach and presents the preliminary results from a rumor-based nationwide registry of genetically isolated populations, named CENISO (Censo Nacional de Isolados), operating in Brazil since 2009. During the first four years of its existence (2009–2013), a total of 191 Rumors were registered and validated, resulting in a prevalence rate of one per million inhabitants of Brazil. When the five statutory geographic regions of Brazil were considered, more Rumors were registered for the Northeast (2.11; 1.74–2.54 per 106) than for the remaining four regions, North, Center-West, Southeast, and South, which did not differ among themselves. About half (86/191) of the recorded rumors were proven to be geographic clusters; of these disorders, 58 were autosomal recessive, 17 autosomal dominant, 5 X-linked, 3 multifactorial, and one environmental (thalidomide embryopathy). PMID:24764753

  13. Establishing the isolated standard model

    Science.gov (United States)

    Wells, James D.; Zhang, Zhengkang; Zhao, Yue

    2017-07-01

    The goal of this article is to initiate a discussion on what it takes to claim "there is no new physics at the weak scale," namely that the Standard Model (SM) is "isolated." The lack of discovery of beyond the SM (BSM) physics suggests that this may be the case. But to truly establish this statement requires proving all "connected" BSM theories are false, which presents a significant challenge. We propose a general approach to quantitatively assess the current status and future prospects of establishing the isolated SM (ISM), which we give a reasonable definition of. We consider broad elements of BSM theories, and show many examples where current experimental results are not sufficient to verify the ISM. In some cases, there is a clear roadmap for the future experimental program, which we outline, while in other cases, further efforts—both theoretical and experimental—are needed in order to robustly claim the establishment of the ISM in the absence of new physics discoveries.

  14. Isolation of technogenic magnetic particles.

    Science.gov (United States)

    Catinon, Mickaël; Ayrault, Sophie; Boudouma, Omar; Bordier, Louise; Agnello, Gregory; Reynaud, Stéphane; Tissut, Michel

    2014-03-15

    Technogenic magnetic particles (TMPs) emitted by various industrial sources, such as smelting plants, end up after atmospheric transfer on the soil surface. In the present study, we characterised the origin and composition of such particles emitted by a large iron smelting plant and deposited on particular substrates, namely tombstones, which act as a very interesting and appropriate matrix when compared to soil, tree bark, lichens or attic dust. The isolation and subsequent description of TMPs require a critical step of separation between different components of the sample and the magnetic particles; here, we described an efficient protocol that fulfils such a requirement: it resorts to water suspension, sonication, repeated magnetic extraction, sedimentation, sieving and organic matter destruction at 550 °C in some instances. The isolated TMPs displayed a noticeable crystalline shape with variable compositions: a) pure iron oxides, b) iron+Cr, Ni or Zn, and c) a complex structure containing Ca, Si, Mg, and Mn. Using Scanning Electron Microscope Energy Dispersive X-ray (SEM-EDX), we obtained profiles of various and distinct magnetic particles, which allowed us to identify the source of the TMPs. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. [Isolated fractures of the atlas].

    Science.gov (United States)

    Kocis, J; Wendsche, P; Visna, P; Muzík, V; Hart, R

    2004-01-01

    To present the current tends in the diagnosis and management of isolated atlas fractures based on the retrospectively evaluated group of patients with this trauma. In the period from 1995 to 2002, we treated 486 injuries to the cervical spine at our department. Out of these, 19 patients sustained an isolated fracture of the first cervical vertebra. This group consisted of 12 men and seven women; the average age was 46.6 years. Neurological findings in 18 patients were classified as Frankel E and, in one, as Frankel A. The causes of injury included a fall from height in five patient, a fall in the street in five pedestrians, a car accident in five patients, a dive into shallow water in three and a shooting injury in one patient. We treated 16 patients conservatively, using a halo-vest in eight patients and a Philadelphia collar also in eight patients. In two patients with unstable atlas injury, we carried out C1-C2 transarticular stabilization according to Magerl. In the patient who had been shot, we removed the bullet transorally. All patients healed completely without signs of instability. One patient with postraumatic pentaplegia, who died within 24 h of surgery due to septic shock, had not been included in the follow-up. Two patients reported neck pain at rest, three after exercise and 13 were without any pain. The patient after C1-C2 transarticular stabilization had a significant restriction of the range of motion in the cervical spine; the rest of the patients were without limitation. None of the patients showed any deterioration of neurological findings during the treatment, nor was any post-traumatic atlantoaxial instability recorded after the therapy was completed. Isolated fractures of the atlas account for 1 to 2% of all spinal fractures. Many fractures may remain unnoticed and, therefore, it is important to X-ray patients with a symptomatic injury to the cervical spine in three standard projection planes (anteroposterior, lateral and transoral). When a

  16. Ectomycorrhizal symbiosis affects functional diversity of rhizosphere fluorescent pseudomonads

    NARCIS (Netherlands)

    Frey-Klett, P.; Chavatte, M.; Clausse, M.L.; Courrier, S.; Roux, Le C.; Raaijmakers, J.M.; Giovanna Martinotti, M.; Pierrat, J.C.; Garbaye, J.

    2005-01-01

    Here we characterized the effect of the ectomycorrhizal symbiosis on the genotypic and functional diversity of soil Pseudomonas fluorescens populations and analysed its possible consequences in terms of plant nutrition, development and health. ¿ Sixty strains of P. fluorescens were isolated from the

  17. Molecular characterization of Danish Cryptosporidium parvum isolates

    DEFF Research Database (Denmark)

    Enemark, Heidi L.; Ahrens, Peter; Juel, Cynthia Dawn

    2002-01-01

    The genetic polymorphism among 271 Danish Cryptosporidium isolates of human and animal origin was studied by partial amplification and sequencing of the Cryptosporidium oocyst wall protein (COWP) gene, the 18S rDNA, and a microsatellite locus.dagger Furthermore, the microsatellite locus was studied...... (P Cryptosporidium isolates of human origin the anthroponotic subgenotype H1 was identified, in addition to the zoonotic subgenotypes C1, C2, and C3. Of 44 human samples, 56.8% were anthroponotic, whereas 40.9% were zoonotic genotypes. One human isolate...... was characterized as C. meleagridis. The porcine Cryptosporidium isolates (N = 4) revealed a pattern which was genetically distinct from human and bovine isolates. Cryptosporidium in a hedgehog (Erinaceus europaeus L.) was identified for the first time. By microsatellite sequencing the hedgehog isolate showed...

  18. Ureaplasma canigenitalium sp. nov., isolated from dogs.

    Science.gov (United States)

    Harasawa, R; Imada, Y; Kotani, H; Koshimizu, K; Barile, M F

    1993-10-01

    Ureaplasma strains isolated from dogs (Canis familiaris) were characterized and compared with the type strains of five previously described species of the genus Ureaplasma, Ureaplasma urealyticum (isolated from humans), Ureaplasma diversum (isolated from cattle), Ureaplasma gallorale (isolated from chickens), Ureaplasma cati (isolated from cats), and Ureaplasma felinum (isolated from cats). The canine strains hydrolyzed urea but not arginine or glucose, were membrane bound, lacked a cell wall, passed through 450-nm-pore-size membrane filters, required cholesterol for growth, and formed minute colonies (diameter, 20 to 140 microns) on agar medium. These canine ureaplasma strains have been reported to be members of four serovars. The four serovars of canine strains fell into a single group on the basis of their genomic properties, as determined by DNA-DNA hybridization. On the basis of these findings, we propose that ureaplasmas with these characteristics belong to a new species, Ureaplasma canigenitalium, with strain D6P-C (= ATCC 51252) as the type strain.

  19. Phylogenetic relationships of Chaetomium isolates based on the ...

    African Journals Online (AJOL)

    Isolates Cg7, Cg8, and Cg9 were closely related to the Australian isolates but distantly related to the isolates from New Zealand. However, all these isolates clustered in the same Australia group as evident in the evolutionary history analysis using parsimony method. European isolate MU-2009 and Australian isolates NA26 ...

  20. Oligotrophic bacteria isolated from clinical materials.

    OpenAIRE

    Tada, Y; Ihmori, M; Yamaguchi, J

    1995-01-01

    Oligotrophic bacteria (oligotrophs) are microorganisms that grow in extremely nutritionally deficient conditions in which the concentrations of organic substances are low. Many oligotrophic bacteria were isolated from clinical materials including urine, sputum, swabbings of the throat, vaginal discharges, and others. Seventy-seven strains of oligotrophic bacteria from 871 samples of clinical material were isolated. A relatively higher frequency of isolation of oligotrophic bacteria was shown ...

  1. Isolated trochlear nerve palsy with midbrain hemorrhage

    Directory of Open Access Journals (Sweden)

    Raghavendra S

    2010-01-01

    Full Text Available Midbrain hemorrhage causing isolated fourth nerve palsy is extremely rare. Idiopathic, traumatic and congenital abnormalities are the most common causes of fourth nerve palsy. We report acute isolated fourth nerve palsy in an 18-year-old lady due to a midbrain hemorrhage probably due to a midbrain cavernoma. The case highlights the need for neuroimaging in selected cases of isolated trochlear nerve palsy.

  2. Isolation and culture of pulmonary endothelial cells.

    OpenAIRE

    Ryan, U S

    1984-01-01

    Methods for isolation, identification and culture of pulmonary endothelial cells are now routine. In the past, methods of isolation have used proteolytic enzymes to detach cells; thereafter, traditional methods for cell passaging have used trypsin/EDTA mixtures. Cells isolated and passaged using proteolytic enzymes have been useful in establishing the field and in verifying certain endothelial properties. However, there is a growing awareness of the role of endothelial cells in processing vas...

  3. Permanent isolation surface barrier: Functional performance

    Energy Technology Data Exchange (ETDEWEB)

    Wing, N.R.

    1993-10-01

    This document presents the functional performance parameters for permanent isolation surface barriers. Permanent isolation surface barriers have been proposed for use at the Hanford Site (and elsewhere) to isolate and dispose of certain types of waste in place. Much of the waste that would be disposed of using in-place isolation techniques is located in subsurface structures, such as solid waste burial grounds, tanks, vaults, and cribs. Unless protected in some way, the wastes could be transported to the accessible environment via transport pathways, such as water infiltration, biointrusion, wind and water erosion, human interference, and/or gaseous release.

  4. Leclercia adecarboxylata isolation: case reports and review.

    Science.gov (United States)

    Anuradha, Mokkapati

    2014-12-01

    Leclercia adecarboxylata is usually isolated as a part of polymicrobial cultures in immunocompetent patients, and as a pure culture in immunocompromised persons. Although generally sensitive to most antibiotics, there are reports of resistant strains. Two case reports of L. adecarboxylata isolation in the lab in pure culture in immunocompetent persons are presented here, L. adecarboxylata being isolated from a vaginal swab in the first case and from a gluteal abscess in the second case. Both the isolates were sensitive to most of the antibiotics tested.

  5. Isolation and characterization of methanogenic bacteria from ...

    African Journals Online (AJOL)

    Isolation and characterization of methanogenic bacteria from brewery wastewater in Kenya. Sylvia Injete Murunga, Duncan Onyango Mbuge, Ayub Njoroge Gitau, Urbanus Ndungwa Mutwiwa, Ingrid Namae Wekesa ...

  6. Loneliness and Social Isolation among Eldely People

    Directory of Open Access Journals (Sweden)

    Engin Püllüm

    2017-11-01

    Full Text Available Social isolation is defined as the process of people losing their contacts with other social resources or their willingness to participate. Social isolation is a grave and widespread problem among seniors in society causing many harmful health conditions. Social isolation may be prevented by defining risk factors in seniors and leading them to suitable resources. The elderly should be encouraged to share their experiences and continue to produce for as long as possible, so that they are prevented from feeling isolated from society and the continuity of their economic productivity is ensured.

  7. Distinguishing Isolated Photons from Jets

    CERN Document Server

    Pieri, Marco; Branson, James G

    2006-01-01

    We have developed isolation and shower-shape variables that are optimized for reducing the jet background for a high transverse-energy photon signal. To help understand the relative importance of each variable, we have computed the background rejection power as a function of signal efficiency for these variables as well as for some simple combinations of variables. We find that a combination of tracker plus ECAL information can give very significant background rejection power. By adding information from the HCAL, the rejection power can be improved. In addition we find that a very significant reduction in background can be achieved by adding photon shower shape information from the ECAL to the Neural Net inputs. About 1 in 200 jets contains a high E_T electromagnetic shower that is reconstructed by the CMS software and is therefore a potential background for photon detection. An additional jet rejection factor of 100 with 80% photon efficiency (or 400 with 50% efficiency) can be achieved by using the isolatio...

  8. Review of the ISOL Method

    CERN Document Server

    Lindroos, M

    2004-01-01

    The ISOL technique was invented in Copenhagen over 50 years ago and eventually migrated to CERN where a suitable proton drive beam was available at the Syncho-Cyclotron. The quick spread of the technique from CERN to many other laboratories has resulted in a large user community, which has assured the continued development of the method, physics in the front-line of fundamental research and the application of the method to many applied sciences. The technique is today established as one of the main techniques for on-line isotope production of high intensity and high quality beams. The thick targets used allows the production of unmatched high intensity radioactive beams. The fact that the ions are produced at rest makes it ideally suitable for low energy experiments and for post acceleration using well established accelerator techniques. The many different versions of the technique will be discussed and the many facilities spread all over the world will be reviewed. The major developments at the existing faci...

  9. Single Cell Isolation and Analysis

    Directory of Open Access Journals (Sweden)

    Ping Hu

    2016-10-01

    Full Text Available Increasing evidence shows that the heterogeneity of individual cells within a genetically identical population can be critical to their peculiar function and fate. Conventional cell based assays mainly analysis the average responses from a population cells, while the difference within individual cells may often be masked. The cell size, RNA transcripts and protein expression level are quite different within individual cells and these variations are key point to answer the problems in cancer, neurobiology, stem cell biology, immunology and developmental biology. To better understand the cell-to-cell variations, the single cell analysis can provide much more detailed information which may be helpful for therapeutic decisions in an increasingly personalized medicine. In this review, we will focus on the recent development in single cell analysis, including methods used in single cell isolation, analysis and some application examples. The review provides the historical background to single cell analysis, discusses limitations, and current and future possibilities in this exciting field of research.

  10. Experimental Study of Vibration Isolation Characteristics of a Geometric Anti-Spring Isolator

    Directory of Open Access Journals (Sweden)

    Lixun Yan

    2017-07-01

    Full Text Available In order to realize low-frequency vibration isolation, a novel geometric anti-spring isolator consisting of several cantilever blade springs are developed in this paper. The optimal design parameters of the geometric anti-spring isolator for different nonlinear geometric parameters are theoretically obtained. The transmissibility characteristic of the geometric anti-spring isolator is investigated through mathematical simulation. A geometric anti-spring isolator with a nonlinear geometric parameter of 0.92 is designed and its vibration isolation performance and nonlinearity characteristic is experimentally studied. The experiment results show that the designed isolator has good low-frequency vibration isolation performance, of which the initial isolation frequency is less than 3.6 Hz when the load weight is 21 kg. The jump phenomena of the response of the isolator under linear frequency sweep excitation are observed, and this result demonstrates that the geometric anti-spring isolator has a complex nonlinearity characteristics with the increment of excitation amplitude. This research work provides a theoretical and experimental basis for the application of the nonlinear geometric anti-spring low-frequency passive vibration isolation technology in engineering practice.

  11. Characterization of potential probiotic bacteria isolated from ...

    African Journals Online (AJOL)

    Characterization of potential probiotic bacteria isolated from sorghum and pearl millet of the semi-arid tropics. ... A total of nine probiotic bacterial isolates were short listed based on these traits. The sequences of 16s rDNA gene ... probiotic foods. Key words: Probiotics, prebiotics, sorghum, pearl millet, product development.

  12. Behavioural reproductive isolation and speciation in Drosophila

    Indian Academy of Sciences (India)

    The origin of premating reproductive isolation continues to help elucidate the process of speciation and is the central event in the evolution of biological species. Therefore, during the process of species formation the diverging populations must acquire some means of reproductive isolation so that the genes from one gene ...

  13. Antibiotic resistance profiles of environmental isolates from ...

    African Journals Online (AJOL)

    ... resistance in the environment. The strong correlation (r=0.97) between the ARPs of the clinical and the environmental isolates may suggest a link between diarrhoeal incidence and the water quality in the region. It is thus imperative that the determination of antibiotic susceptibility/resistance patterns of isolated microbes is ...

  14. Steroids isolated from Millettia versicolor Baker (Fabaceae ...

    African Journals Online (AJOL)

    Steroids isolated from Millettia versicolor Baker (Fabaceae) ... African Journal of Biotechnology ... The objective of this investigation was to isolate and determine the chemical constituents of the leaves of Millettia versicolor Baker, a medicinal plant used in the traditional pharmacopoeias of Central Africa, essentially for its ...

  15. methicillin resistance in staphylococcal isolates from

    African Journals Online (AJOL)

    The study assessed the importance of Staphylococcus aureus as a urinary pathogen and the incidence of multidrug resistant (MDR), methicillin-resistant Staphylococcus aureus (MRSA). A total of 86 staphylococcal isolates made up of 50 clinical isolates from urine samples submitted to the Medical Microbiology Laboratory ...

  16. Virus isolation: Specimen type and probable transmission

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. Virus isolation: Specimen type and probable transmission. Over 500 CHIK virus isolations were made. 4 from male Ae. Aegypti (?TOT). 6 from CSF (neurological involvement). 1 from a 4-day old child (transplacental transmission.

  17. Molecular characterization of Trichoderma sp. isolated from ...

    African Journals Online (AJOL)

    The genetic relatedness among 15 isolates of Trichoderma sp. was analyzed with six micro-satellite primers. ISSR profiles showed 83.7% genetic diversity among the isolates with the formation of four clusters. Analysis of dendrogram revealed that similarity coefficient ranged from 0.27 to 0.95. ITS-PCR of rDNA region with ...

  18. Isolation and bioactivity of endophytic filamentous actinobacteria ...

    African Journals Online (AJOL)

    mineral salts agar. Of the 280 isolates recovered, 154 were from roots, 73 from stems and 53 from leaves. Bioactivity test of crude fermentation extracts were performed on all the isolates. About 41.1% of the extracts showed activity against liver ...

  19. Isolation of glycoproteins from brown algae.

    OpenAIRE

    Surendraraj, Alagarsamy; Farvin Koduvayur Habeebullah , Sabeena; Jacobsen, Charlotte

    2015-01-01

    The present invention relates to a novel process for the isolation of unique anti-oxidative glycoproteins from the pH precipitated fractions of enzymatic extracts of brown algae. Two brown seaweeds viz, Fucus serratus and Fucus vesiculosus were hydrolysed by using 3 enzymes viz, Alcalase, Viscozyme and Termamyl and the glycoproteins were isolated from these enzyme extracts.

  20. Isolation and characterization of extreme halophilic archaea

    International Nuclear Information System (INIS)

    Franze, Madlen; Cherkouk, Andrea

    2017-01-01

    Extreme halophilic archaea from the family Halobactereacea represent a dominant part of the microbial community present in saline soils as well as rock salts. By using a culture-dependent approach different Haloarchaea could be isolated and were phylogenetic analysed. Interestingly, isolates closely related to different Halobacterium spp. were found in both environments.

  1. Experiments on seismic isolation in Italy

    International Nuclear Information System (INIS)

    Bonacina, G.; Bettinali, F.; Martelli, A.; Olivieri, M.

    1992-01-01

    Static and dynamic tests have been performed in Italy on high damping steel-laminated elastomer bearings in various scales, rubber specimens and structures isolated by means of such bearings, in the framework of studies in progress to support seismic isolation development. Tests on rubber specimens and bearings have already provided important data (vertical and horizontal stiffness, damping, creep, temperature, aging and scale effects, etc.), necessary for the development and validation of numerical models, comparison with the test results of isolated structure mockups and actual buildings, and improvement of design guidelines. Dynamic experiments of structures concerned both full-scale and scaled isolated structure mock-ups and actual isolated buildings (one of those forming the SIP Administration Center at Ancona, an isolated house at Squillace, Calabria). Both snap-back tests and forced excitation experiments were performed, to rather large displacements. The latter were both sinusoidal and (on a 1/4 scale mock-up) seismic, with one- and multidirectional simultaneous excitations. Test results have already demonstrated the adequacy of seismic isolation and have provided data useful for the comparison with single bearing test results and validation of numerical models for the analysis of isolated structures. This paper reports the main features and results of tests performed or in progress. Further tests planned have been mentioned in the Status Report. Numerical analysis of measured data and guidelines development have been discussed in separate technical papers. (author)

  2. Phenotypic and Genotypic Characterization of Nosocomial Isolates ...

    African Journals Online (AJOL)

    The prevalence of MRSA strains among S. aureus isolates was 20.7 %. The overall resistance of MRSA to a variety of antibiotics tested was linezolid, 48.7 %; ciprofloxacin, 15.3 %; sulfamethoxazole/trimethoprim (TMS), 14.0 %; gentamicin, 12.7 %; and rifampicin, 6.7 %. All MRSA isolates were positive for femB and mecA ...

  3. Enumeration, Isolation and Antibiotic Susceptibility Profile of ...

    African Journals Online (AJOL)

    ABSTRACT: A study was carried out between February and March, 2012, to enumerate, isolate and identify bacteria associated with mobile cell phones .... prevalence of bacteria isolated from mobile phones of the marketers might be as a result of .... Behavior of Listeria monocytogens in a. Pseudomonas putida biofilm on a ...

  4. Isolation and characterization of cellulolytic Bacillus licheniformis ...

    African Journals Online (AJOL)

    Eight cellulose degrading bacteria were isolated from compost and were identified as Bacillus licheniformis by 16S rRNA sequencing. Among the eight isolates, Bacillus licheniformis B4, B7 and B8 showed the highest cellulase activity. B. licheniformis B4 and B8 showed the maximum cellulase activity during the stationary ...

  5. K-Basin isolation barrier seal

    International Nuclear Information System (INIS)

    Ruff, E.S.

    1994-10-01

    This report documents various aspects of the design, analysis, procurement, and fabrication of the hydraulic seal on the isolation barriers to be installed in the 100-K Area spent nuclear fuel basin. The isolation barrier is used to keep water in the basin in the event of an earthquake

  6. Isolation of phytohormones producing plant growth promoting ...

    African Journals Online (AJOL)

    Isolation of phytohormones producing plant growth promoting rhizobacteria from weeds growing in Khewra salt range, Pakistan and their implication in providing ... salt range and the results were compared with strain Rak isolated from rhizosphere (EC: 0.2 dS/m) of Solanum surratense grown in arid area of district Attock.

  7. Behavioural reproductive isolation and speciation in Drosophila

    Indian Academy of Sciences (India)

    2012-03-29

    Mar 29, 2012 ... sexual isolation is the central event in the evolution of biological species and plays a key role in .... ic traits including body size, pigmentation, cuticular hydrocarbon composition and wing beat frequency, that are ... other parts of the world, such as the case of 'microhabitat' sexual isolation in the West African ...

  8. Isolation, characterization and antimicrobial activity of Streptomyces ...

    African Journals Online (AJOL)

    A total of 30 Streptomyces isolates (28 from soil and 2 from water) were isolated and purified from hot-springs areas in the northern part of Jordan. Four strains were thermopile. They grew at 45 and 55°C but not at 28°C. Strains were described morphologically on four different media: on glycerol yeast extract, oatmeal, yeast ...

  9. Genetic homogeneity among Ugandan isolates of Xanthomonas ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-02

    Nov 2, 2009 ... Key words: Banana Xanthomonas wilt, DNA fingerprints, genetic diversity, Xanthomonas campestris pv. .... Bacterial isolates. Thirty two isolates of Xcm were collected in the year 2005 from. Ugandan banana growing districts affected by BXW (Table 1;. Figure 1). ..... Fundamental methods. Springer Lab ...

  10. Assessment of Effectiveness of Geologic Isolation Systems

    International Nuclear Information System (INIS)

    Soldat, J.K.; Napier, B.A.

    1982-01-01

    The program for Assessment of Effectiveness of Geologic Isolation Systems (AEGIS) is managed through Pacific Northwest Laboratory's Water and Land Resources Department and is funded through the Battelle Office of Nuclear Waste Isolation (ONWI). The Ecological Sciences Department was involved in two subtasks under AEGIS: Dose Methodology Development and Reference Site Initial Analysis (RSIA) for a Salt Dome

  11. ASPECTS OF THE ISOLATION AND CHARACTERIZATON OF ...

    African Journals Online (AJOL)

    A local isolate of Alternaria alternata isolated from soil under the decaying cassava peels heap was screened for the production of a-amylase and hydrolysis of starch. The maximal dextrinizing amylolytic activity of the partially purified enzyme was obtained at temperature of 600C and pH 7.0. Apart from glucose, sucrose and ...

  12. Isolation and characterization of native Bacillus thuringiensis ...

    African Journals Online (AJOL)

    ... (<30% mortality) or non insecticidal activity. However, results of motility, hemolytic activity, antibiotic-susceptibility patterns, and crystal shape, seem to suggest that many of our Bt isolates may exhibit parasporins activity. Key words: Bacillus thuringiensis, parasporal crystal, isolation, biochemical type, insecticidal, cry gene, ...

  13. Noncommunicating Isolated Enteric Duplication Cyst in the ...

    African Journals Online (AJOL)

    Noncommunicating isolated enteric duplications in the abdomen are an extremely rare variant of enteric duplications with their own blood supply. We report a case of a noncommunicating isolated ileal duplication in a 10-month-old boy. He was admitted because of severe abdominal distension and developed irritability ...

  14. Antiproliferative heparin (glycosaminoglycans) isolated from giant ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-05-18

    May 18, 2009 ... Heparin was isolated from two bivalve mollusks, Tridacna maxima (giant clam) and Perna viridis (green mussel). The isolated heparin was quantified in crude as well as purified samples and they were estimated as 2.72 and 2.2 g/kg (in crude) and 260 and 248 mg/g (in purified samples) in T. maxima and.

  15. SCREENING AND BIOASSAY-GUIDED ISOLATION OF ...

    African Journals Online (AJOL)

    DR. AMINU

    2013-06-01

    Jun 1, 2013 ... from the leaves and stem-root of the plant were sequentially extracted with petroleum ether, chloroform, ethyl acetate and ... Keywords: Bioassay-guided isolation, antimicrobial activity, Laggera mollis, clinical isolates, extracts. INTRODUCTION ... technology (Das et al., 2009). The powdered leaf/stem-root ...

  16. Antiproliferative heparin (glycosaminoglycans) isolated from giant ...

    African Journals Online (AJOL)

    Heparin was isolated from two bivalve mollusks, Tridacna maxima (giant clam) and Perna viridis (green mussel). The isolated heparin was quantified in crude as well as purified samples and they were estimated as 2.72 and 2.2 g/kg (in crude) and 260 and 248 mg/g (in purified samples) in T. maxima and P. viridis, ...

  17. hydroxyalkanoate (PHAs) producing bacteria isolated from ...

    African Journals Online (AJOL)

    SERVER

    2007-07-04

    Jul 4, 2007 ... ing the ribosomal 16s RNA gene, the best isolates evaluation in both balloon flask and ... They were then transferred to the Microbiology laboratory at the. Universidad Nacional de .... Number of promising isolates according to carbon source in which PHAs accumulate. n = 108. software, employing the ...

  18. Isolation, identifications and antimicrobial susceptibility pattern of ...

    African Journals Online (AJOL)

    A cross-sectional study was conducted from November 2013 to April 2014 to isolate coagulase positive Staphylococcus (CPS) from subclinical mastitic (SCM) lactating cows, to establishing prevalence, to identify risk factors and to determine the antimicrobial susceptibility pattern of CPS isolates in and around Haramaya ...

  19. Isolation, characterization and primary screening of soil ...

    African Journals Online (AJOL)

    SARAH

    2014-02-28

    Feb 28, 2014 ... secondary metabolites against selected multidrug resistant bacteria isolates. Methodology: Half kg soil samples were collected 15cm below the ground. Starch Casein Agar (SCA) was used to isolate actinomycetes. Fifteen different ... Journal of Applied Biosciences 74:6072– 6079. ISSN 1997–5902 ...

  20. Scalable Detection and Isolation of Phishing

    NARCIS (Netherlands)

    Moreira Moura, Giovane; Pras, Aiko

    2009-01-01

    This paper presents a proposal for scalable detection and isolation of phishing. The main ideas are to move the protection from end users towards the network provider and to employ the novel bad neighborhood concept, in order to detect and isolate both phishing e-mail senders and phishing web

  1. Study on three dimensional seismic isolation system

    International Nuclear Information System (INIS)

    Morishita, Masaki; Kitamura, Seiji

    2003-01-01

    Japan Nuclear Cycle Development Institute (JNC) and Japan Atomic Power Company (JAPC) launched joint research programs on structural design and three-dimensional seismic isolation technologies, as part of the supporting R and D activities for the feasibility studies on commercialized fast breeder reactor cycle systems. A research project by JAPC under the auspices of the Ministry of Economy, Trade, and Industry (METI) with technical support by JNC is included in this joint study. This report contains the results of the research on the three-dimensional seismic isolation technologies, and the results of this year's study are summarized in the following five aspects. (1) Study on Earthquake Condition for Developing 3-dimensional Base Isolation System. The case study S2 is one of the maximum ground motions, of which the records were investigated up to this time. But a few observed near the fault exceed the case study S2 in the long period domain, depending on the fault length and conditions. Generally it is appropriate that the response spectra ratio (vertical/horizontal) is 0.6. (2) Performance Requirement for 3-dimensional Base Isolation System and Devices. Although the integrity map of main equipment/piping dominate the design criteria for the 3-dimensional base isolation system, the combined integrity map is the same as those of FY 2000, which are under fv=1Hz and over hv=20%. (3) Developing Targets and Schedule for 3-dimensional Isolation Technology. The target items for 3-dimensional base isolation system were rearranged into a table, and developing items to be examined concerning the device were also adjusted. A development plan until FY 2009 was made from the viewpoint of realization and establishment of a design guideline on 3-dimensional base isolation system. (4) Study on 3-dimensional Entire Building Base Isolation System. Three ideas among six ideas that had been proposed in FY2001, i.e., '3-dimensional base isolation system incorporating hydraulic

  2. Isolation of Pasteurella multocida from broiler chickens

    Directory of Open Access Journals (Sweden)

    Sri Poernomo

    1996-06-01

    Full Text Available Pasteurella multocida, the etiological agent of fowl cholera, was isolated from five, 32 days oldbroilerchickens in the late of 1992. The chickens were from a farm located in Bogor area, raised in cages and each flock consisted of 1,550 broilers . Therewere 230 birds, aging from 28-31 days old, died with clinical signs of lameness and difficulty in breathing. Serological test of the isolate revealed serotype Aof Carter classification . To prove its virulences, the isolate was then inoculated into 3 mice subcutaneously. The mice died less then 24 hours postinoculation and P. multocida can be reisolated . The sensitivity test to antibiotics and sulfa preparations showed that the isolate was sensitive to ampicillin, doxycyclin, erythromycin, gentamycin, sulfamethoxazol-trimethoprim and baytril, but resistance to tetracyclin, kanamycin and oxytetracyclin. This is the first report of P. multocida isolation in broiler chickens in Indonesia, and it is intended to add information on bacterial diseases in poultry in Indonesia.

  3. Fault Isolation for Shipboard Decision Support

    DEFF Research Database (Denmark)

    Lajic, Zoran; Blanke, Mogens; Nielsen, Ulrik Dam

    2010-01-01

    Fault detection and fault isolation for in-service decision support systems for marine surface vehicles will be presented in this paper. The stochastic wave elevation and the associated ship responses are modeled in the frequency domain. The paper takes as an example fault isolation of a containe......Fault detection and fault isolation for in-service decision support systems for marine surface vehicles will be presented in this paper. The stochastic wave elevation and the associated ship responses are modeled in the frequency domain. The paper takes as an example fault isolation...... of a containership on which a decision support system has been installed and it will be demonstrated that all the faults can be isolated. The paper shows how a shipboard decision support system could become highly reliable and comprise built-in supervision of the quality of the sensor signals that are crucial...

  4. Effect of isolation techniques on the characteristics of pigeon pea (Cajanus cajan) protein isolates.

    Science.gov (United States)

    Adenekan, Monilola K; Fadimu, Gbemisola J; Odunmbaku, Lukumon A; Oke, Emmanuel K

    2018-01-01

    In this study, the effect of different isolation techniques on the isolated proteins from pigeon pea was investigated. Water, methanol, ammonium sulfate, and acetone were used for the precipitation of proteins from pigeon pea. Proximate composition, and antinutritional and functional properties of the pigeon pea flour and the isolated proteins were measured. Data generated were statistically analyzed. The proximate composition of the water-extracted protein isolate was moisture 8.30%, protein 91.83%, fat 0.25%, ash 0.05%, and crude fiber 0.05%. The methanol-extracted protein isolate composition was moisture 7.87%, protein 91.83%, fat 0.17%, and ash 0.13%, while crude fiber and carbohydrates were not detected. The composition of the ammonium sulfate-extracted protein isolate was moisture 7.73%, protein 91.73%, fat 0.36, ash 0.13%, and crude fiber 0.67%. The acetone-extracted protein isolate composition was moisture 8.03%, protein 91.50%, ash 0.67%, and fat 0.30%, but crude fiber and carbohydrates were not detected. The isolate precipitated with ammonium sulfate displayed the highest foaming capacity (37.63%) and foaming stability (55.75%). Isolates precipitated with methanol and acetone had the highest water absorption capacity (160%). Pigeon pea protein isolates extracted with methanol and ammonium sulfate had the highest oil absorption capacity of 145%. Protein isolates recovered through acetone and methanol had the highest emulsifying capacity of 2.23% and emulsifying stability of 91.47%, respectively. The proximate composition of the recovered protein isolates were of high purity. This shows the efficiency of the extraction techniques. The isolates had desirable solubility index. All the isolation techniques brought significant impact on the characteristics of the isolated pigeon pea protein.

  5. EMPLACEMENT DRIFT ISOLATION DOOR CONTROL SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    N.T. Raczka

    1998-09-17

    The purpose of this analysis is to review and refine key design concepts related to the control system presently under consideration for remotely operating the emplacement drift isolation doors at the potential subsurface nuclear waste repository at Yucca Mountain. This analysis will discuss the key design concepts of the control system that may be utilized for remotely monitoring, opening, and closing the emplacement drift isolation doors. The scope and primary objectives of this analysis are to: (1) Discuss the purpose and function of the isolation doors (Presented in Section 7.1). (2) Review the construction of the isolation door and other physical characteristics of the doors that the control system will interface with (Presented in Section 7.2). (3) Discuss monitoring and controlling the operation of the isolation doors with a digital control system (either a Programmable Logic Controller (PLC) system or a Distributed Control System (DCS)) (Presented in Section 7.3). (4) Discuss how all isolation doors can be monitored and controlled from a subsurface central control center (Presented in Section 7.4). This analysis will focus on the development of input/output (I/O) counts including the types of I/O, redundancy and fault tolerance considerations, and processor requirements for the isolation door control system. Attention will be placed on operability, maintainability, and reliability issues for the system operating in the subsurface environment with exposure to high temperatures and radiation.

  6. EMPLACEMENT DRIFT ISOLATION DOOR CONTROL SYSTEM

    International Nuclear Information System (INIS)

    N.T. Raczka

    1998-01-01

    The purpose of this analysis is to review and refine key design concepts related to the control system presently under consideration for remotely operating the emplacement drift isolation doors at the potential subsurface nuclear waste repository at Yucca Mountain. This analysis will discuss the key design concepts of the control system that may be utilized for remotely monitoring, opening, and closing the emplacement drift isolation doors. The scope and primary objectives of this analysis are to: (1) Discuss the purpose and function of the isolation doors (Presented in Section 7.1). (2) Review the construction of the isolation door and other physical characteristics of the doors that the control system will interface with (Presented in Section 7.2). (3) Discuss monitoring and controlling the operation of the isolation doors with a digital control system (either a Programmable Logic Controller (PLC) system or a Distributed Control System (DCS)) (Presented in Section 7.3). (4) Discuss how all isolation doors can be monitored and controlled from a subsurface central control center (Presented in Section 7.4). This analysis will focus on the development of input/output (I/O) counts including the types of I/O, redundancy and fault tolerance considerations, and processor requirements for the isolation door control system. Attention will be placed on operability, maintainability, and reliability issues for the system operating in the subsurface environment with exposure to high temperatures and radiation

  7. Mycobacteria isolated from Chesapeake Bay fish.

    Science.gov (United States)

    Stine, C B; Kane, A S; Baya, A M

    2010-01-01

    Mycobacteriosis in fish can result in ulcers, emaciation, and in some cases death. Mycobacteria have been previously isolated from a variety of Chesapeake Bay fish species, and the current study was designed to identify potential host specificity and location fidelity of mycobacterial isolates. Mycobacteria were isolated from wild fish of the Chesapeake Bay collected from the Upper Bay, the Choptank River, Herring Bay, the Chicamacomico River, the Pocomoke River and the Potomac River in 2003-2006. Mycobacterial isolates were recovered from striped bass, Morone saxatilis, Atlantic menhaden, Brevoortia tyrannus, white perch, Morone americana, summer flounder, Paralichthys dentatus, spot, Leiostomus xanthurus, largemouth bass, Micropterus salmoides, channel catfish, Ictalurus punctatus, common carp, Cyprinus carpio carpio, spotted seatrout, Cynoscion nebulosus, killifish, Fundulus sp., blueback herring, Alosa aestivalis, American gizzard shad, Dorosoma cepedianum and American silver perch, Bairdiella chrysoura. Twenty-nine well-defined mycobacterial groups resulted from gas chromatography dendrogram clustering of isolates. The majority of groups included more than one host species and more than one site of collection. However, four groups contained only striped bass isolates, three of which were similar to M. shottsii. Therefore, multiple Chesapeake Bay fish species are colonized with multiple mycobacterial isolates, of which few appear to be host or location specific.

  8. Are Isolated Indigenous Populations Headed toward Extinction?

    Directory of Open Access Journals (Sweden)

    Robert S Walker

    Full Text Available At least 50 indigenous groups spread across lowland South America remain isolated and have only intermittent and mostly hostile interactions with the outside world. Except in emergency situations, the current policy of governments in Brazil, Colombia, and Peru towards isolated tribes is a "leave them alone" strategy, in which isolated groups are left uncontacted. However, these no-contact policies are based on the assumption that isolated populations are healthy and capable of persisting in the face of mounting external threats, and that they can maintain population viability in the long-term. Here, we test this assumption by tracking the sizes and movements of cleared horticultural areas made by 8 isolated groups over the last 10-14 years. We used deforestation data derived from remote sensing Landsat satellite sensors to identify clearings, and those were then validated and assessed with high-resolution imagery. We found only a single example of a relatively large and growing population (c. 50 cleared ha and 400 people, whereas all of the other 7 groups exhibited much smaller villages and gardens with no sizable growth through time. These results indicated that the smaller groups are critically endangered, and it prompts an urgent re-thinking of policies toward isolated populations, including plans for well-organized contacts that may help save lives and rescue isolated indigenous populations from imminent extinction.

  9. Are Isolated Indigenous Populations Headed toward Extinction?

    Science.gov (United States)

    Walker, Robert S; Kesler, Dylan C; Hill, Kim R

    2016-01-01

    At least 50 indigenous groups spread across lowland South America remain isolated and have only intermittent and mostly hostile interactions with the outside world. Except in emergency situations, the current policy of governments in Brazil, Colombia, and Peru towards isolated tribes is a "leave them alone" strategy, in which isolated groups are left uncontacted. However, these no-contact policies are based on the assumption that isolated populations are healthy and capable of persisting in the face of mounting external threats, and that they can maintain population viability in the long-term. Here, we test this assumption by tracking the sizes and movements of cleared horticultural areas made by 8 isolated groups over the last 10-14 years. We used deforestation data derived from remote sensing Landsat satellite sensors to identify clearings, and those were then validated and assessed with high-resolution imagery. We found only a single example of a relatively large and growing population (c. 50 cleared ha and 400 people), whereas all of the other 7 groups exhibited much smaller villages and gardens with no sizable growth through time. These results indicated that the smaller groups are critically endangered, and it prompts an urgent re-thinking of policies toward isolated populations, including plans for well-organized contacts that may help save lives and rescue isolated indigenous populations from imminent extinction.

  10. Isolated microalbuminuria indicates a poor medical prognosis.

    Science.gov (United States)

    Scheven, Lieneke; Van der Velde, Marije; Lambers Heerspink, Hiddo J; De Jong, Paul E; Gansevoort, Ron T

    2013-07-01

    Microalbuminuria is often regarded as a sign of end-organ damage due to diabetes and/or hypertension, and as such to be associated with an increased risk for cardiovascular events. It has been questioned whether isolated microalbuminuria, that is microalbuminuria in the absence of a cardiovascular disease (CVD) history, hypertension and diabetes has clinical relevance. Included were 8356 subjects who participated in the first four screening rounds of the PREVEND study, a prospective, community-based, observational cohort study. Isolated microalbuminuria was defined as microalbuminuria (30-300 mg/24 h), in the absence of a CVD history, hypertension (blood pressuredefinition of isolated microalbuminuria, in which 2250 person-years of follow-up were available. In subjects with isolated microalbuminuria, the incidence rates of cardiovascular events and mortality, hypertension and diabetes were 15.3, 28.9 and 8.9 per 1000 person-year follow-up, respectively. Subjects with isolated microalbuminuria had an increased risk for cardiovascular events and mortality [crude HR 2.23 (1.63-3.07); Phypertension [OR 1.95 (1.47-2.59); Phypertension and/or diabetes. This increased risk remained significant after adjustment for age and gender. The relative risk held by isolated microalbuminuria was similar to the relative risk held by microalbuminuria in subjects that did have a CVD history, hypertension and/or diabetes. Isolated microalbuminuria indicates a poor prognosis and warrants medical attention.

  11. Different Babesia canis isolates, different diseases.

    Science.gov (United States)

    Schetters, T P; Moubri, K; Précigout, E; Kleuskens, J; Scholtes, N C; Gorenflot, A

    1997-11-01

    Using surface immunofluorescence isolate-specific antigens were detected on the membrane of erythrocytes infected with Babesia parasites. In addition, the strains reacted differently with Plasmagel in that the European isolate (B.c. canis) could be purified on Plasmagel effectively, whereas infected erythrocytes of the South-African isolate (B.c. rossi) could not. Experimental infection of dogs with Babesia canis isolates from geographically different areas revealed different pathology. The European isolate obtained from France exhibited transient parasitaemia, usually below 1%, associated with low PCV values and congestion of internal organs. Clinical disease was correlated with an effect on the coagulation system, and not with peripheral parasitaemia. Infection of dogs with South-African-derived isolate induced high parasitaemia usually much higher than 1%, which required chemotherapeutic treatment. In these animals clinical disease was correlated with peripheral parasitaemia and not with parameters of the coagulation system. The results show that the etiology of disease caused by these isolates of B.c. canis and B.c. rossi is different. This might have implications for the development of vaccines against these infections.

  12. 6DOF active microtremor isolation system

    International Nuclear Information System (INIS)

    Katayama, Kazuyoki; Takahashi, Yoshinori; Murai, Nobuyoshi; Naganou, Masatake

    1990-01-01

    The present article outlines an effort at research and development of a 6DOF (degree of freedom) active microtremor isolation system, and the vibration isolation characteristic of this active vibration system is discussed on the basis of analytical and experimental results. The SDOF (single degree of freedom) active vibration control system is described focusing on the isolation characteristics of an ideal vibration control system, transient response of an ideal vibration control system, and experimental results with a SDOF active vibration control system. A SDOF active vibration isolation system as shown in Fig. 1 is formulated by integrating the passive isolation elements and an actuator. The second half of the paper discusses features of the 6DOF active microtremor isolation system, focusing on a prototype system for experiments and experimental results obtained with a 6DOF active microtremor isolation system. For electron and positron accelerators, a constant environment should be maintained in order to improve the reproducibility of experiments. In order to achieve the super microvibration environment, it is necessary to introduce new type microvibration control techniques. (N.K.)

  13. Characterisation of clinically isolated Streptococcus pyogenes from balanoposthitis patients, with special emphasis on emm89 isolates.

    Science.gov (United States)

    Hasegawa, Tadao; Hata, Nanako; Matsui, Hideyuki; Isaka, Masanori; Tatsuno, Ichiro

    2017-04-01

    Streptococcus pyogenes causes a variety of diseases, such as pharyngitis and toxic shock syndrome. In addition, this bacterium is a causative agent of balanoposthitis. To reveal the bacteriological characteristics of the isolates from balanoposthitis patients, we analysed 47 isolates. In addition, novel clade genotype emm89 S. pyogenes isolates have been reported to be spreading worldwide recently. Hence, we further analysed eight emm89 isolates. A drug susceptibility experiment was performed and emm types were determined. More detailed experiments, such as PCR analysis for the presence of virulence-associated genes and MLST analysis, were performed especially using emm89 isolates. All isolates were sensitive to ampicillin, but 34 % of the isolates were resistant to at least one antibiotic. The emm types of the isolates varied, with emm89 and emm11 being the most prevalent, but the emm1 type was not detected. The analysis of emm89 isolates revealed that drug susceptibilities varied. All isolates were negative for the hasABC gene and produced active NADase that are characteristics of novel clade genotype emm89 S. pyogenes. MLST analysis demonstrated that six isolates were of the ST101 type, the most predominant type reported thus far, but two isolates were of the ST646 type. According to the PCR analysis used to determine the presence of streptococcal pyrogenic exotoxin-related genes, the six ST101 isolates were further classified into four groups. These results suggest that balanoposthitis is caused by a variety of types of S. pyogenes, with novel clade genotype emm89 isolates playing a role in balanoposthitis infections in Japan.

  14. Genetic differences between avian and human isolates of Candida dubliniensis.

    LENUS (Irish Health Repository)

    McManus, Brenda A

    2009-09-01

    When Candida dubliniensis isolates obtained from seabird excrement and from humans in Ireland were compared by using multilocus sequence typing, 13 of 14 avian isolates were genetically distinct from human isolates. The remaining avian isolate was indistinguishable from a human isolate, suggesting that transmission may occur between humans and birds.

  15. 42 CFR 71.33 - Persons: Isolation and surveillance.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Persons: Isolation and surveillance. 71.33 Section...: Isolation and surveillance. (a) Persons held in isolation under this subpart may be held in facilities suitable for isolation and treatment. (b) The Director may require isolation where surveillance is...

  16. Isolators Including Main Spring Linear Guide Systems

    Science.gov (United States)

    Goold, Ryan (Inventor); Buchele, Paul (Inventor); Hindle, Timothy (Inventor); Ruebsamen, Dale Thomas (Inventor)

    2017-01-01

    Embodiments of isolators, such as three parameter isolators, including a main spring linear guide system are provided. In one embodiment, the isolator includes first and second opposing end portions, a main spring mechanically coupled between the first and second end portions, and a linear guide system extending from the first end portion, across the main spring, and toward the second end portion. The linear guide system expands and contracts in conjunction with deflection of the main spring along the working axis, while restricting displacement and rotation of the main spring along first and second axes orthogonal to the working axis.

  17. ISOLATION OF CLOSTRIDIUM TETANI FROM SOIL.

    Science.gov (United States)

    SANADA, I; NISHIDA, S

    1965-03-01

    Sanada, Ichiro (Kanazawa University, Kanazawa, Japan), and Shoki Nishida. Isolation of Clostridium tetani from soil. J. Bacteriol. 89:626-629. 1965.-The higher the temperatures applied to soil specimens, the weaker the toxigenicity of Clostridium tetani strains isolated from them. The glucose- and maltose-fermenting ability of these isolates was inversely proportional to their toxigenicity. The biological properties of atoxic strains were indistinguishable from those of C. tetanomorphum. Since a considerable number of toxic strains fermented glucose and maltose, these criteria are of doubtful value for differentiating C. tetani from C. tetanomorphum.

  18. Social isolation and all-cause mortality

    DEFF Research Database (Denmark)

    Laugesen, Kristina; Baggesen, Lisbeth Munksgård; Schmidt, Sigrún Alba Jóhannesdóttir

    2018-01-01

    Social isolation is associated with increased mortality. Meta-analytic results, however, indicate heterogeneity in effect sizes. We aimed to provide new evidence to the association between social isolation and mortality by conducting a population-based cohort study. We reconstructed the Berkman...... cumulative mortality and adjusted mortality rate ratios (MRR) associated with SNI. We adjusted for potential important confounders, including psychiatric and somatic status, lifestyle, and socioeconomic status. Cumulative 7-year mortality in men was 11% for SNI 0/1 and 5.4% for SNI 4 and in women 9...... isolation was associated with 60-70% increased mortality. Having no partner was associated with highest MRR....

  19. Fault Detection and Isolation for Spacecraft

    DEFF Research Database (Denmark)

    Jensen, Hans-Christian Becker; Wisniewski, Rafal

    2002-01-01

    This article realizes nonlinear Fault Detection and Isolation for actuators, given there is no measurement of the states in the actuators. The Fault Detection and Isolation of the actuators is instead based on angular velocity measurement of the spacecraft and knowledge about the dynamics...... of the satellite. The algorithms presented in this paper are based on a geometric approach to achieve nonlinear Fault Detection and Isolation. The proposed algorithms are tested in a simulation study and the pros and cons of the algorithms are discussed....

  20. Fault Isolation for Shipboard Decision Support

    DEFF Research Database (Denmark)

    Lajic, Zoran; Blanke, Mogens; Nielsen, Ulrik Dam

    2010-01-01

    Fault detection and fault isolation for in-service decision support systems for marine surface vehicles will be presented in this paper. The stochastic wave elevation and the associated ship responses are modeled in the frequency domain. The paper takes as an example fault isolation...... of a containership on which a decision support system has been installed and it will be demonstrated that all the faults can be isolated. The paper shows how a shipboard decision support system could become highly reliable and comprise built-in supervision of the quality of the sensor signals that are crucial...

  1. The heterogeneity of socially isolated older adults: a social isolation typology.

    Science.gov (United States)

    Machielse, Anja

    2015-01-01

    Recent statistics show a growing number of older adults who are living alone and are socially isolated. It is against this background that, in recent years, many interventions have been developed to address social isolation among the elderly. Evaluative studies show that most interventions are hardly effective, though. An important reason for this is the heterogeneity of the socially isolated. This article offers insight into this heterogeneity by presenting a typology with different profiles of socially isolated older adults and the intervention implications of this typology. The typology is derived from an extensive qualitative study on socially isolated elderly individuals in the Netherlands. The typology imposes some degree of order to a diversity of circumstances, ambitions, and possibilities of the socially isolated elderly, thereby deepening the understanding of the heterogeneity of this population. The definition of social isolation used in this study starts from a societal angle of incidence, namely the current policy context of Western European welfare states, in which governments emphasize the importance of independence and self-reliance of their citizens. Developed from that perspective, the typology provides a theoretical basis for applying interventions aimed at increasing self-reliance of social isolated elderly. This perspective on social isolation also has consequences for the way in which the effectiveness of interventions to alleviate social isolation is assessed.

  2. Protein distribution in lupin protein isolates from Lupinus angustifolius L. prepared by various isolation techniques.

    Science.gov (United States)

    Muranyi, Isabel S; Volke, Daniela; Hoffmann, Ralf; Eisner, Peter; Herfellner, Thomas; Brunnbauer, Markus; Koehler, Peter; Schweiggert-Weisz, Ute

    2016-09-15

    Differences in the protein distribution of various protein isolates from Lupinus angustifolius L. Vitabor were identified as affected by the isolation procedure (alkaline and/or salt-induced extraction followed by isoelectric and/or dilutive precipitation). Protein isolates extracted in alkaline solution showed higher protein yields (26.4-31.7%) compared to salt-induced extraction (19.8-30.0%) or combined alkaline and salt-induced extraction (23.3-25.6%). Chemical variations among the protein isolates especially occurred within the albumins. Protein isolates precipitated isoelectrically showed the highest contents, whereas protein isolates precipitated by dilutive showed the lowest contents of conglutin δ. Furthermore, the alkaline subunits of conglutin α and conglutin γ decreased during alkaline extraction compared to salt-induced extraction. A decrease in protein-bound polar and basic amino acids was shown after protein isolation. In contrast, the amounts of nonpolar, aliphatic, aromatic, hydroxylated and sulfur-rich amino acids were higher in the lupin protein isolates compared to the lupin flakes. However, the functional side chains could not be related to the specific molecular arrangements of the protein isolates, as a similar amino acid composition was found among the protein isolates. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Isolated torsion of fallopian tube. Radiological findings

    International Nuclear Information System (INIS)

    Tomas Fanjul, L.; Aldea Martinez, J.; Fernandez Matia, G.; Rodrigo Verguizas, J.; Fernandez Alvarez, G.; Galindo Vicente, M.C.

    1993-01-01

    Isolated tubal torsion is a very uncommon disorder that is rarely diagnosed preoperatively. We present a case and review the literature, which only provides ultrasonographic findings in 5 cases reported to date. 11 refs

  4. Isolated splenic peliosis in an immunocompromised patient

    African Journals Online (AJOL)

    cited by Gushiken1). Isolated splenic peliosis is extremely rare, and most cases are associated with peliosis hepatis. Establishing the incidence of splenic peliosis is difficult, since the condition usually remains asymptomatic or is discovered ...

  5. SEISMIC ISOLATION OF NUCLEAR POWER PLANTS

    Directory of Open Access Journals (Sweden)

    ANDREW S. WHITTAKER

    2014-10-01

    The funding by the United States Nuclear Regulatory Commission of a research project to the Lawrence Berkeley National Laboratory and MCEER/University at Buffalo facilitated the writing of a soon-to-be-published NUREG on seismic isolation. Funding of MCEER by the National Science Foundation led to research products that provide the technical basis for a new section in ASCE Standard 4 on the seismic isolation of safety-related nuclear facilities. The performance expectations identified in the NUREG and ASCE 4 for seismic isolation systems, and superstructures and substructures are described in the paper. Robust numerical models capable of capturing isolator behaviors under extreme loadings, which have been verified and validated following ASME protocols, and implemented in the open source code OpenSees, are introduced.

  6. Isolation and mutation of cellulolytic fungi.

    Science.gov (United States)

    Gupta, J K; Shirkot, C K; Dhawan, S

    1981-01-01

    Nineteen fungi were isolated from different soil samples on the basis of clear zones formed on Rose Bengal Cellulose agar medium. In shake flasks th isolate K1 gave 12.1 units/ml of CMCase activity. A mutant of the isolate K1, KM7, was selected after N-methyl-N'-nitro-N-nitrosoguanidine treatment of the wild-type. This mutant differed morphologically from the parent strain on RBCA medium and gave 36.2 units/ml of CMCase activity which represented about 50% of the enzyme yield from the standard organism, Trichoderma viride QM 9414 (80 units/ml of CMCase activity). The isolate K1, which was identified as a Phoma species, produced 48 units of beta-glucosidase. The yield of beta-glucosidase was increased about 8-fold in the mutant KM7 and was about 68% higher than the level found in T. viride QM 9414.

  7. Antigenic typing Polish isolates of canine parvovirus

    Energy Technology Data Exchange (ETDEWEB)

    Mizak, B. [National Veterinary Research Institute, Pulawy (Poland); Plucienniczak, A. [Polish Academy ofd Sciences. Microbiology and Virology Center, Lodz (Poland)

    1995-12-31

    Polish strains of canine parvovirus isolated between 1982 and 1993 were examined to determine the extent to which the virus has evolved antigenically and genetically over eleven years. Two CPV isolates obtained in Warsaw in 1982 and Pulawy in 1993, were examined using monoclonal antibody typing, restriction analysis and sequencing VP-2 protein gene. Five other isolates from Warsaw and Pulawy were tested with the panel of monoclonal antibodies specific to CPV-2, CPV-2a and common for canine parvovirus, feline panleukopenia virus and milk enteritis virus. Results of the studies demonstrated that all isolates tested represented CPV-2a antigenic type. Rapid antigenic strain replacement recorded by Parrish and Senda in the U.S.A and Japan was not confirmed in Poland. (author). 30 refs, 2 tabs.

  8. Antibiotic Sensitivity Pattern of Microorganisms Isolated from ...

    African Journals Online (AJOL)

    ., Pseudomonas sp., Corynebacterium sp., Micrococcus sp. and four fungal species namely; Aspergillus spp., Fusarium sp., Mucor sp. and Penicillium spp. were identified. Majority of the bacteria were isolated from fish samples from Benin.

  9. Antimicrobial substances produced by bacteria isolated from ...

    African Journals Online (AJOL)

    -resistant Staphylococcus aureus (MRSA). The MRSA were isolated from sheep, bovine, camel and poultry meat samples collected from retails shops and slaughter houses located in Amman area, Jordan. B. mallei NB-8 and C. kutscheri NB-1 ...

  10. A case of familial isolated hemihyperplasia

    Science.gov (United States)

    Heilstedt, Heidi A; Bacino, Carlos A

    2004-01-01

    Background Hemihyperplasia (hemihypertrophy) is defined as asymmetric body overgrowth of one or more body parts. Hemihyperplasia can be isolated or be part of well-defined syndromes such as in the case of Beckwith-Wiedemann syndrome (BWS). Isolated hemihyperplasia is usually sporadic, but a number of familial occurrences have been described. Case presentation We describe a Tunisian family in which three maternal cousins and their maternal grandfather present with isolated hemihyperplasia. Conclusions The etiology of isolated hemihyperplasia is unknown although in BWS, genomic imprinting has been shown to play a role in the asymmetric overgrowth. Given the similarity between these two conditions, it is possible that both may share a common pathogenesis. We also discuss the possible genetic mechanisms leading to the production of hemihyperplasia in this family. PMID:15040809

  11. A case of familial isolated hemihyperplasia

    Directory of Open Access Journals (Sweden)

    Bacino Carlos A

    2004-02-01

    Full Text Available Abstract Background Hemihyperplasia (hemihypertrophy is defined as asymmetric body overgrowth of one or more body parts. Hemihyperplasia can be isolated or be part of well-defined syndromes such as in the case of Beckwith-Wiedemann syndrome (BWS. Isolated hemihyperplasia is usually sporadic, but a number of familial occurrences have been described. Case presentation We describe a Tunisian family in which three maternal cousins and their maternal grandfather present with isolated hemihyperplasia. Conclusions The etiology of isolated hemihyperplasia is unknown although in BWS, genomic imprinting has been shown to play a role in the asymmetric overgrowth. Given the similarity between these two conditions, it is possible that both may share a common pathogenesis. We also discuss the possible genetic mechanisms leading to the production of hemihyperplasia in this family.

  12. Extracellular enzymes of Fusarium graminearum isolates

    Directory of Open Access Journals (Sweden)

    Gisele Eleonora Kikot

    2010-08-01

    Full Text Available Fusarium graminearum isolates from three different agroecological regions in Argentina were examined according to the production of different extracellular enzyme activities of potential biotechnological interest: pectinases (PGase: polygalacturonase and PMGase: polymethylgalacturonase, cellulase (CMCase: carboxymethylcellulase and hemicellulase (xylanase. The isolates were grown in minimum salt medium supplemented with 0.25% glucose, 0.125% citric pectin and 0.125% oat bran as carbon sources and/or enzyme inducers. PGase activity was detected early (after two days of incubation in all the cultures; it was found to be the highest for all the isolates. PMGase was high only for those isolates of the II region. CMCase and endoxylanase activities were particularly found at late stages (after four and seven days of incubation, respectively and the maximum values were lower than pectinase activities.

  13. Isolation, characterization and antimicrobial activity of Streptomyces ...

    African Journals Online (AJOL)

    DR TONUKARI

    2013-12-18

    . Physiological and biochemical tests showed that the highest number of Streptomyces isolates were able to hydrolyze tyrosine was 26 (87%). This was followed by 25 (83%) for starch, 24 (80%) for urea, 21 (70%) for casein ...

  14. Isolation and characterization of a bacterial celluloseproducing ...

    African Journals Online (AJOL)

    year ripened persimmon vinegar, which belonged to the family of Acetobacteracea based on its morphological and physiological characteristics. The phylogenetic position of the isolated strain was most closely related to Gluconacetobacter ...

  15. Collection, Isolation and Culture of Marine Algae.

    Science.gov (United States)

    James, Daniel E.

    1984-01-01

    Methods of collecting, isolating, and culturing microscopic and macroscopic marine algae are described. Three different culture media list of chemicals needed and procedures for preparing Erdschreiber's and Provasoli's E. S. media. (BC)

  16. Antibiogram Profile of Klebsiella pneumoniae Isolates from ...

    African Journals Online (AJOL)

    Others were Staphylococcus aureus, Escherichia coli, Proteus mirabilis, Proteus vulgaris, Proteus morganii, Proteus rettgerri, Pseudomonas aeruginosa, Alcaligenes fecalis, Acinetobacter calcoaceticus and Candida albicans. The K. pneumoniae isolates were sensitive to ofloxacin, ceftazidime and gentamycin, moderately ...

  17. Enterocin from Enterococcus faecium isolated from mangrove ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-11-16

    Nov 16, 2009 ... Enterococcus faecium isolated from mangrove environment produced enterocin and it showed broad inhibitory spectrum against gram positive and gram negative bacteria such as Lactobacillus plantarum,. Enterococcus facealis, Listeria monocytogens and Salmonella paratyphii. The optimum production of.

  18. Enterocin from Enterococcus faecium isolated from mangrove ...

    African Journals Online (AJOL)

    Enterococcus faecium isolated from mangrove environment produced enterocin and it showed broad inhibitory spectrum against gram positive and gram negative bacteria such as Lactobacillus plantarum, Enterococcus facealis, Listeria monocytogens and Salmonella paratyphii. The optimum production of bacteriocin ...

  19. Molecular characterization of Danish Cryptosporidium parvum isolates

    DEFF Research Database (Denmark)

    Enemark, Heidi L.; Ahrens, Peter; Juel, Cynthia Dawn

    2002-01-01

    The genetic polymorphism among 271 Danish Cryptosporidium isolates of human and animal origin was studied by partial amplification and sequencing of the Cryptosporidium oocyst wall protein (COWP) gene, the 18S rDNA, and a microsatellite locus.dagger Furthermore, the microsatellite locus was studied...... directly using fragment analysis. A comparative analysis of DNA sequences showed the presence of 3 different subgenotypes (C1, C2 and C3) in C. parvum isolates from Danish cattle, with prevalences of 16.7, 17.2 and 73.1% including 13 (7.0%) mixed infections. Subgenotype C1 was significantly more prevalent...... (P isolates of human origin the anthroponotic subgenotype H1 was identified, in addition to the zoonotic subgenotypes C1, C2, and C3. Of 44 human samples, 56.8% were anthroponotic, whereas 40.9% were zoonotic genotypes. One human isolate...

  20. Nitrogen uptake kinetics of freshly isolated zooxanthellae

    Digital Repository Service at National Institute of Oceanography (India)

    Wafar; Wafar; Rajkumar, R.

    Zooxanthellae freshly isolated from the coral host Pocillopora damicornis exhibited substrate-saturable uptake kinetics for ammonium, nitrate and urea. Maximum uptake velocity for ammonium [10.1 nmol. ( mu chl-a)./1h/1] was greater than...