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1
Etebarian, Hassan-Reza, Peter L. Sholberg, Kenneth C. Eastwell, and Ronald J. Sayler. "Biological control of apple blue mold withPseudomonas fluorescens." Canadian Journal of Microbiology 51, no. 7 (July 1, 2005): 591–98. http://dx.doi.org/10.1139/w05-039.
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Pseudomonas fluorescens isolate 1100-6 was evaluated as a potential biological control agent for apple blue mold caused by Penicillium expansum or Penicillium solitum. Both the wild-type isolate 1100-6 and a genetically modified derivative labeled with the gene encoding the green fluorescent protein (GFP) were compared. The P. fluorescens isolates with or without GFP equally reduced the growth of Penicillium spp. and produced large zones of inhibition in dual culture plate assays. Cell-free metabolites produced by the bacterial antagonists reduced the colony area of Penicillium isolates by 17.3% to 78.5%. The effect of iron chelate on the antagonistic potential of P. fluorescens was also studied. The use of iron chelate did not have a major effect on the antagonistic activity of P. fluorescens. With or without GFP, P. fluorescens significantly reduced the severity and incidence of apple decay by 2 P. expansum isolates after 11 d at 20 °C and by P. expansum and P. solitum after 25 d at 5 °C when the biocontrol agents were applied in wounds 24 or 48 h before challenging with Penicillium spp. Populations of P. fluorescens labeled with the GFP were determined 1, 9, 14, and 20 d after inoculation at 5 °C. The log CFU/mL per wound increased from 6.95 at the time of inoculation to 9.12 CFU/mL (P < 0.05) 25 d after inoculation at 5 °C. The GFP strain did not appear to penetrate deeply into wounds based on digital photographs taken with an inverted fluorescence microscope. These results indicate that P. fluorescens isolate 1100-6 could be an important new biological control for apple blue mold.Key words: Penicillium expansum, P. solitum, postharvest disease, Malus, GFP.
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Gopal, Surendra, Reshma Francis, and A. K. Sreelatha. "Impact of soil temperature, pH and carbon dioxide on the population and efficiency of fluorescent pseudomonad in the rhizosphere soil of Pokkali rice." Environment Conservation Journal 24, no. 1 (January 8, 2023): 163–70. http://dx.doi.org/10.36953/ecj.10262239.
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The present study was aimed at the evaluation of soil temperature, pH and carbon dioxide evolution on the number and efficiency of fluorescent pseudomonads around the root system of Pokkali rice at Vytilla in Ernakulam district of Kerala. Two plots (40 m2) comprising control (without application of Pseudomonas fluorescens) and P. fluorescens treated plants were used for the field experiment. The isolates of fluorescent Pseudomonads or Pseudomonas fluorescence were counted and their efficiency was assessed for IAA, ammonia, HCN and siderophore production. Simultaneously, soil temperature, pH, and carbon dioxide evolution were also recorded. A total of 6 fluorescent pseudomonads (VPJU, VPJL, VPAU1, VPAU2, VPAU3 and VPAU4) were found during the crop period. All the isolates produced IAA and ammonia with varying degrees of intensity. Three isolates (VPAU1, VPAU3 and VPAU4) produced HCN, and no microbial isolates produced siderophore. The effect of soil temperature, pH, EC and carbon dioxide evolution was correlated with the number of fluorescent pseudomonads in the soil. The bacteria were significantly afflicted by pH and EC, whereas soil temperature and CO2 evolution did not show any effect on the number of fluorescent pseudomonads. There was no significant influence of soil temperature, pH, EC and carbon dioxide evolution on indole acetic acid production, ammonia, and HCN production. Inoculated Pseudomonas fluorescence did not survive in Pokkali rice fields. However, further studies are needed for at least three seasons in Pokkali soils to confirm the results of the present study.
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Silva, Gildo Almeida da, and Erik Amazonas de Almeida. "Production of yellow-green fluorescent pigment by Pseudomonas fluorescens." Brazilian Archives of Biology and Technology 49, no. 3 (May 2006): 411–19. http://dx.doi.org/10.1590/s1516-89132006000400009.
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A medium was prepared from brewery waste yeast with and without mineral salts to study growth and yellow-green fluorescent pigment production (YGFP) by Pseudomonas fluorescens. The King's medium used for detection of siderophore production were expressively weaker inductors of YGFP formation when compared to FYE medium. Although FYE and CYE could be used for growth of P. fluorescens, only FYE was an attractive medium for detection of YGFP strain producers.
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Shu, Huizhen, Haiming Chen, Xiaolong Wang, Yueying Hu, Yonghuan Yun, Qiuping Zhong, Weijun Chen, and Wenxue Chen. "Antimicrobial Activity and Proposed Action Mechanism of 3-Carene against Brochothrix thermosphacta and Pseudomonas fluorescens." Molecules 24, no. 18 (September 6, 2019): 3246. http://dx.doi.org/10.3390/molecules24183246.
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3-Carene is an antimicrobial monoterpene that occurs naturally in a variety of plants and has an ambiguous antibacterial mechanism against food-borne germs. The antibacterial effects and action mechanism of 3-carene against Gram-positive Brochothrix thermosphacta ACCC 03870 and Gram-negative Pseudomonas fluorescens ATCC 13525 were studied. Scanning electron microscopy (SEM) examination and leakage of alkaline phosphatase (AKP) verified that 3-carene caused more obvious damage to the morphology and wall structure of B. thermosphacta than P. fluorescens. The release of potassium ions and proteins, the reduction in membrane potential (MP), and fluorescein diacetate (FDA) staining further confirmed that the loss of the barrier function of the cell membrane and the leakage of cytoplasmic contents were due to the 3-carene treatment. Furthermore, the disorder of succinate dehydrogenase (SDH), malate dehydrogenase (MDH), pyruvate kinase (PK), and ATP content indicated that 3-carene could lead to metabolic dysfunction and inhibit energy synthesis. In addition, the results from the fluorescence analysis revealed that 3-carene could probably bind to bacterial DNA and affect the conformation and structure of genomic DNA. These results revealed that 3-carene had strong antibacterial activity against B. thermosphacta and P. fluorescens via membrane damage, bacterial metabolic perturbations, and genomic DNA structure disruption, interfering in cellular functions and even causing cell death.
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Aloysius Ng. Lende, Laurensius Lehar, and Heny MC Sine. "Application of organic fertilizer and Pseudomonas fluorescens on the growth and yield of shallot cultivar Sabu Raijua (Allium ascalonicum L .) in dry land." GSC Advanced Research and Reviews 5, no. 2 (November 30, 2020): 123–30. http://dx.doi.org/10.30574/gscarr.2020.5.2.0105.
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The specific objectives of this study were 1 ) knowing certain types of organic fertilizers on the growth of shallots 2 ) knowing the concentrations of Pseudomonas fluorescenss certain the growth of shallots, 3 ) knowing the types of organic fertilizers and the concentrations Pseudomonas fluorescens specificity increase the optimal yield of shallots. To achieve this goal, this research was conducted using factorial experiments with a split Plot Design with 10 treatments and 3 replications. So that there are 10 treatment combinations of a total number of 30 experimental plots. There were 2 factors that were tried, namely the first factor of Organic Fertilizer as the main plot, namely: cow manure 10 ton ha-1 (K1), chicken manure 10 ton ha-1 (K2). While the second factor as the subplot is the concentration of Pseudomonas fluorescens: Watering with water (as a control) 100 ml (P0), Watering with a concentration of Pseudomonas fluorescens 5 ml + normal water 95 ml (P1), Watering with a concentration of Pseudomonas fluorescens 10 + ordinary water 90 ml (P2), sprinkling with a concentration of Pseudomonas fluorescens 15 ml + 85 ml plain water (P3), Flushing with a concentration of Pseudomonas fluorescens 20 + ordinary water 80 ml (P4). The shallot cultivar of Sabu Raijua which was given organic fertilizer of 10 tonnes of chicken manure. Ha-1 and a concentration of Pseudomonas fluorescens 20 + 80 ml of plain water gave the highest growth component at the age of 10 WAP, namely at the age of 10 WAP, namely plant height (37.667cm). Leaves (34, 800 trees), number of tillers (10, 533 trees). The results of shallot bulbs of Sabu Raijua cultivar from organic fertilizer treatment of 10 ton ha-chicken manure1s with a concentration of Pseudomonas fluorescens 20 ml + 80 ml water resulted in components, namely tuber weight per plot (276.70 g ), number of tubers per plot (291, 70 tubers ).
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Dynes, James J., John R. Lawrence, Darren R. Korber, George D. W. Swerhone, Gary G. Leppard, and Adam P. Hitchcock. "Morphological and biochemical changes inPseudomonas fluorescensbiofilms induced by sub-inhibitory exposure to antimicrobial agents." Canadian Journal of Microbiology 55, no. 2 (February 2009): 163–78. http://dx.doi.org/10.1139/w08-109.
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Confocal laser scanning microscopy (CLSM) and scanning transmission X-ray microscopy (STXM) were used to examine the morphological and biochemical changes in Pseudomonas fluorescens biofilms grown in the presence of subinhibitory concentrations of 4 antimicrobial agents: triclosan, benzalkonium chloride, chlorhexidine dihydrochloride, and trisodium phosphate. CLSM analyses using the stains SYTO9 and propidium iodide indicated that the antimicrobial agents affected cell membrane integrity and cellular density to differing degrees. However, fluorescein diacetate assays and plate counts demonstrated that the cells remained metabolically active. Fluorescent lectin binding assays showed that changes in the arrangement and composition of the exopolymer matrix of the biofilms also occurred and that these changes depended on the antimicrobial agent. Detailed single cell analyses using STXM provided evidence that the cell morphology, and the spatial distribution and relative amounts of protein, lipids and polysaccharides in the biofilms and within the cells were different for each antimicrobial. The distribution of chlorhexidine in the biofilm, determined from its distinct spectral signature, was localized mainly inside the bacterial cells. Each antimicrobial agent elicited a unique response; P. fluorescens cells and biofilms changed their morphology and architecture, as well as the distribution and abundance of biomacromolecules, in particular the exopolymer matrix. Pseudomonas fluorescens also exhibited adaptation to benzalkonium chloride at 10 µg/mL. Our observations point to the importance of changes in the quantity and chemistry of the exopolymeric matrix in the response to antimicrobial agents and suggest their importance as targets for control.
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Armarkar, Sarika A., R. M. Gade, and Mina D. Koche. "Growth Promotion Activity And Growth Pattern Of Pseudomonas Fluorescens On Different Solid Media." Journal of Plant Disease Sciences 17, no. 1 (August 9, 2022): 22–27. http://dx.doi.org/10.48165/jpds.2022.1706.
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Study was conducted in vitro to study the growth promotion activity and growth pattern of Pseudomonas fluorescens on different solid media. Soil samples were collected randomly from rhizosphere of citrus plants for isolation of Pseudomonas. Twenty six isolates was isolated, out of twenty six isolates eight isolates showed abiliity of siderophore production, thirteen isolates showed positiveness for IAA production, nine isolates showed phosphate solubilization and seven isolates were positive for HCN production. For growth pattern study of P. fluorescens three different media i.e. King’s B, Pseudomonas agar and nutrient agar used. All the isolates showed fast growth on King’s B followed by Pseudomonas agar and nutrient agar. Mostly Pseudomonas fluorescens produced greenish yellow coloured colonies on King’s B and Pseudomonas agar and dull yellowish coloured colony and creamy white coloured colony on nutrient agar. Fluorescent pigmentation was observed on King’B and Pseudomonas agar medium.
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Downing, Katrina J., Graeme Leslie, and Jennifer A. Thomson. "Biocontrol of the Sugarcane Borer Eldana saccharina by Expression of the Bacillus thuringiensis cry1Ac7 andSerratia marcescens chiA Genes in Sugarcane-Associated Bacteria." Applied and Environmental Microbiology 66, no. 7 (July 1, 2000): 2804–10. http://dx.doi.org/10.1128/aem.66.7.2804-2810.2000.
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ABSTRACT The cry1Ac7 gene of Bacillus thuringiensisstrain 234, showing activity against the sugarcane borer Eldana saccharina, was cloned under the control of the tacpromoter. The fusion was introduced into the broad-host-range plasmid pKT240 and the integration vector pJFF350 and without thetac promoter into the broad-host-range plasmids pML122 and pKmM0. These plasmids were introduced into a Pseudomonas fluorescens strain isolated from the phylloplane of sugarcane and the endophytic bacterium Herbaspirillum seropedicae found in sugarcane. The ptac-cry1Ac7 construct was introduced into the chromosome of P. fluorescens using the integration vector pJFF350 carrying the artificial interposon Omegon-Km. Western blot analysis showed that the expression levels of the integratedcry1Ac7 gene were much higher under the control of thetac promoter than under the control of its endogenous promoter. It was also determined that multicopy expression in P. fluorescens and H. seropedicae of ptac-cry1Ac7 carried on pKT240 caused plasmid instability with no detectable protein expression. In H. seropedicae, more Cry1Ac7 toxin was produced when the gene was cloned under the control of the Nmr promoter on pML122 than in the opposite orientation and bioassays showed that the former resulted in higher mortality of E. saccharina larvae than the latter. P. fluorescens 14::ptac-tox resulted in higher mortality of larvae than did P. fluorescens14::tox. An increased toxic effect was observed when P. fluorescens 14::ptac-tox was combined with P. fluorescens carrying the Serratia marcescens chitinase gene chiA, under the control of the tac promoter, integrated into the chromosome.
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Velusamy, Palaniyandi, J. Ebenezar Immanuel, Samuel S. Gnanamanickam, and Linda Thomashow. "Biological control of rice bacterial blight by plant-associated bacteria producing 2,4-diacetylphloroglucinol." Canadian Journal of Microbiology 52, no. 1 (January 1, 2006): 56–65. http://dx.doi.org/10.1139/w05-106.
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Certain plant-associated strains of fluorescent Pseudomonas spp. are known to produce the antimicrobial antibiotic 2,4-diacetylphloroglucinol (DAPG). It has antibacterial, antifungal, antiviral, and antihelminthic properties and has played a significant role in the biological control of tobacco, wheat, and sugar beet diseases. It has never been reported from India and has not been implicated in the biological suppression of a major disease of the rice crop. Here, we report that a subpopulation of 27 strains of plant-associated Pseudomonas fluorescens screened in a batch of 278 strains of fluorescent pseudomonads produced DAPG. The DAPG production was detected by a PCR-based screening method that used primers Phl2a and Phl2b and amplified a 745-bp fragment characteristic of DAPG. HPLC,1H NMR, and IR analyses provided further evidence for its production. We report also that this compound inhibited the growth of the devastating rice bacterial blight pathogen Xanthomonas oryzae pv. oryzae in laboratory assays and suppressed rice bacterial blight up to 59%–64% in net-house and field experiments. Tn5 mutants defective in DAPG production (Phl–) of P. fluorescens PTB 9 were much less effective in their suppression of rice bacterial blight.Key words: biocontrol, 2,4-diacetylphloroglucinol, Pseudomonas fluorescens, rice, Xanthomonas oryzae pv. oryzae.
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TAKEUCHI, KAZUE, CLAUDIA M. MATUTE, ASHRAF N. HASSAN, and JOSEPH F. FRANK. "Comparison of the Attachment of Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium, and Pseudomonas fluorescens to Lettuce Leaves." Journal of Food Protection 63, no. 10 (October 1, 2000): 1433–37. http://dx.doi.org/10.4315/0362-028x-63.10.1433.
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Attachment of Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium, and Pseudomonas fluorescens on iceberg lettuce was evaluated by plate count and confocal scanning laser microscopy (CSLM). Attachment of each microorganism (∼108 CFU/ml) on the surface and the cut edge of lettuce leaves was determined. E. coli O157:H7 and L. monocytogenes attached preferentially to cut edges, while P. fluorescens attached preferentially to the intact surfaces. Differences in attachment at the two sites were greatest with L. monocytogenes. Salmonella Typhimurium attached equally to the two sites. At the surface, P. fluorescens attached in greatest number, followed by E. coli O157:H7, L. monocytogenes, and Salmonella Typhimurium. Attached microorganisms on lettuce were stained with fluorescein isothiocyanate and visualized by CSLM. Images at the surface and the cut edge of lettuce confirmed the plate count data. In addition, microcolony formation by P. fluorescens was observed on the lettuce surface. Some cells of each microorganism at the cut edge were located within the lettuce tissues, indicating that penetration occurred from the cut edge surface. The results of this study indicate that different species of microorganisms attach differently to lettuce structures, and CSLM can be successfully used to detect these differences.
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Hunjan, Mandeep Singh, Anjali Thakur, and Pushpinder Paul Singh. "Identification and characterization of Pseudomonas fluorescensstrains effective against Xanthomonasoryzaepv. oryzae causing bacterial blight of rice in Punjab, India." Journal of Applied and Natural Science 9, no. 1 (March 1, 2017): 253–61. http://dx.doi.org/10.31018/jans.v9i1.1181.
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For the control of bacterial blight of rice caused by Xanthomonasoryzaepv. oryzae, sixty four Pseudomonas fluorescens strains were recovered from rice and wheat rhizosphere. These strains were identified on the basis of internal transcribed spacer (ITS) region. It was observed that the strains showing fluorescence in the selective media showed the amplification of the targeted P. fluorescens specific ITS region. The strains were also characterized for the production of the antibiotic 2, 4-diacetylphloroglucinol (DAPG) using phlDlocus. The characteristic 750bp region was amplified in all the DAPG producing strains. These strains were evaluated against X. oryzae in vitro by dual culture method. The P. fluorescens strains found effective in vitro were further tested in field for their antagonistic potentiality and disease suppression ability. P. fluorescens strain number Pf-4-R showed maximum inhibition i.e. of 5.5 mm against the test pathogen X. oryzaepv. oryzae. Talc based powder formulation of the effective strain Pf-4-R used for field evaluation, showed that pre-inoculation foliar sprays were effective in controlling bacterial blight of rice with disease suppression efficiency ranging from 29.6 to 65.6 percent in different treatments.
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Yee, Dennis C., Jennifer A. Maynard, and Thomas K. Wood. "Rhizoremediation of Trichloroethylene by a Recombinant, Root-Colonizing Pseudomonas fluorescensStrain Expressing Toluene ortho-Monooxygenase Constitutively." Applied and Environmental Microbiology 64, no. 1 (January 1, 1998): 112–18. http://dx.doi.org/10.1128/aem.64.1.112-118.1998.
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ABSTRACT Trichloroethylene (TCE) was removed from soils by using a wheat rhizosphere established by coating seeds with a recombinant, TCE-degrading Pseudomonas fluorescens strain that expresses the tomA + (tolueneo-monooxygenase) genes from Burkholderia cepacia PR123(TOM23C). A transposon integration vector was used to insert tomA +into the chromosome of P. fluorescens 2-79, producing a stable strain that expressed constitutively the monooxygenase at a level of 1.1 nmol/min · mg of protein (initial TCE concentration, 10 μM, assuming that all of the TCE was in the liquid) for more than 280 cell generations (36 days). We also constructed a salicylate-inducible P. fluorescens strain that degraded TCE at an initial rate of 2.6 nmol/min · mg of protein in the presence of 10 μM TCE [cf. B. cepacia G4 PR123(TOM23C), which degraded TCE at an initial rate of 2.5 nmol/min · mg of protein]. A constitutive strain,P. fluorescens 2-79TOM, grew (maximum specific growth rate, 0.78 h−1) and colonized wheat (3 × 106CFU/cm of root) as well as wild-type P. fluorescens 2-79 (maximum specific growth rate, 0.77 h−1; level of colonization, 4 × 106 CFU/cm of root). Rhizoremediation of TCE was demonstrated by using microcosms containing the constitutive monooxygenase-expressing microorganism, soil, and wheat. These closed microcosms degraded an average of 63% of the initial TCE in 4 days (20.6 nmol of TCE/day · plant), compared to the 9% of the initial TCE removed by negative controls consisting of microcosms containing wild-type P. fluorescens2-79-inoculated wheat, uninoculated wheat, or sterile soil.
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Nielsen, T. H., D. Sørensen, C. Tobiasen, J. B. Andersen, C. Christophersen, M. Givskov, and J. Sørensen. "Antibiotic and Biosurfactant Properties of Cyclic Lipopeptides Produced by Fluorescent Pseudomonas spp. from the Sugar Beet Rhizosphere." Applied and Environmental Microbiology 68, no. 7 (July 2002): 3416–23. http://dx.doi.org/10.1128/aem.68.7.3416-3423.2002.
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ABSTRACT Cyclic lipopeptides (CLPs) with antibiotic and biosurfactant properties are produced by a number of soil bacteria, including fluorescent Pseudomonas spp. To provide new and efficient strains for the biological control of root-pathogenic fungi in agricultural crops, we isolated approximately 600 fluorescent Pseudomonas spp. from two different agricultural soils by using three different growth media. CLP production was observed in a large proportion of the strains (approximately 60%) inhabiting the sandy soil, compared to a low proportion (approximately 6%) in the loamy soil. Chemical structure analysis revealed that all CLPs could be clustered into two major groups, each consisting of four subgroups. The two major groups varied primarily in the number of amino acids in the cyclic peptide moiety, while each of the subgroups could be differentiated by substitutions of specific amino acids in the peptide moiety. Production of specific CLPs could be affiliated with Pseudomonas fluorescens strain groups belonging to biotype I, V, or VI. In vitro analysis using both purified CLPs and whole-cell P. fluorescens preparations demonstrated that all CLPs exhibited strong biosurfactant properties and that some also had antibiotic properties towards root-pathogenic microfungi. The CLP-producing P. fluorescens strains provide a useful resource for selection of biological control agents, whether a single strain or a consortium of strains was used to maximize the synergistic effect of multiple antagonistic traits in the inoculum.
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Lee, Spencer, and Robert Jonas. "Genomic Evolution in Pseudomonas fluorescens as a Result of Gradual Temperature Changes." Fine Focus 9, no. 1 (May 8, 2023): 84–96. http://dx.doi.org/10.33043/ff.9.1.84-96.
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As climate change continues to affect global temperatures, organisms will need to not only adapt but evolve to survive the changing climate conditions. Temperature selection experiments were performed on Pseudomonas fluorescens to select for growth at lower temperatures. The P. fluorescens temperature selection experiment selected for cells that can grow at a new minimum temperature which is over 20˚C lower than the optimal growth temperature (25-30˚C). Previous experiments established the low end of P. fluorescens’s growth temperature as 4˚C. The genomes of the newly selected and reference strains of P. fluorescens were sent for sequencing, and the results showed differences in protein sequence between the two strains. This experiment is a model for evolution as a result of gradual temperature change (similar to climate change) over generations, and the resulting genomic changes recorded show which protein families could evolve as an organism adapts to a gradually changing temperature.
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Kristoffersen, Arne Skodvin. "Fotosyntese og fluorescens." Naturen 142, no. 04 (October 24, 2018): 157–62. http://dx.doi.org/10.18261/issn.1504-3118-2018-04-04.
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Gottlieb, Tom, Glenn Funnell, and Iain Gosbell. "Pseudomonas fluorescens pseudobacteraemia." Medical Journal of Australia 155, no. 11-12 (December 1991): 854–55. http://dx.doi.org/10.5694/j.1326-5377.1991.tb94085.x.
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YOON, Hong Mook, Sung Hoon MOON, and Young Hwan SONG. "Characterization of Biosurfactant Produced by Pseudomonas fluorescens PD101." Korean Journal of Fisheries and Aquatic Sciences 36, no. 3 (June 1, 2003): 230–38. http://dx.doi.org/10.5657/kfas.2003.36.3.230.
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Dalterio, R. A., W. H. Nelson, D. Brut, J. F. Sperry, J. F. Tanguay, and S. L. Suib. "The Steady-State and Decay Characteristics of Primary Fluorescence from Live Bacteria." Applied Spectroscopy 41, no. 2 (February 1987): 234–41. http://dx.doi.org/10.1366/000370287774986804.
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The intrinsic steady-state fluorescence and fluorescence decay of Staphylococcus epidermidis, Pseudomonas fluorescens, Enterobacter cloacae, Escherichia coli, and Bacillus subtilis have been observed. Excitation spectra were obtained while emission at 430, 455, 487 and 514 nm was being monitored. Emission spectra were obtained with the use of excitation wavelengths of 340, 365, 405, 430 and 460 nm. Fluorescence lifetimes were measured at 430, 487, and 514 nm while selective excitation was caused at 340, 405, and 430 nm. The complex nature of the excitation and emission spectra reflects the presence of a number of different fluorophores. Attempts have been made to describe portions of the bacterial fluorescence in terms of the measured fluorescence properties including lifetimes of molecular components known for their widespread occurrence in bacteria and their relatively high quantum yields. Candidate fluorophores which have been considered include the pteridines, the structurally related flavins, and the pyridine coenzymes. The observation that characteristic sets of lifetimes have been obtained for each organism suggests that measurements of fluorescence lifetimes may be helpful in the rapid characterization of bacteria. Results are especially definitive in cases such as Pseudomonas fluorescens, where one marker fluorophore, a pteridine, is produced in large amounts.
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Hasanuddin, Hasanuddin. "UJI AKTIVITAS ANTIBIOSIS PSEUDOMONADS PENDARFLUOR TERHADAP Rigidoporus lignosus (Klotszch) Imazeki PENYEBAB PENYAKIT AKAR PUTIH." Jurnal Hama dan Penyakit Tumbuhan Tropika 11, no. 1 (February 10, 2011): 87–94. http://dx.doi.org/10.23960/j.hptt.11187-94.
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The potential of fluorescent bacteria as biological control agents for white root disease caused by Rigidoporus lignosus has been investigated. Isolation of bacteria from the soil using S1 media produced two fluorescent bacteria isolates. Using the Microbact 12A+12B method, both bacteria were identified as Pseudomonas fluorescens and P. aeruginosa. These two species of bacteria were then used as antibiosis activity test against R. lignosus. Four series antibiosis activity tests were done, that were antibiosis test of media culture bacteria growth to R. lignosus colony, antibiosis test of dry fluorescent pigment extract to R. lignosus, influence of Fe3+ to antibiosis activity of bacteria test, and affinity of media supernatant to Fe3+. The results were: antibiosis activity of King’s B (KB) media was more effective than media 523 in the inhibition of R. lignosus colony growth. There was no significant different antibiosis activity of dry fluorescent pigment extract from media KB and media 523 in the inhibition of R. lignosus colony growth. The level of Fe3+ in the media might influence antibiosis activity of fluorescent pigment. Affinity test of KB supernatant from fluorescent bacteria culture with Fe3+ showed an absorption peak of 410 nm on spectrophotometer, and none for the fungi. These results indicate that P. fluorescens and P. aeruginosa produce cathecol-type siderophore with high affinity against Fe3+ compared with hydroxamate-type siderophore which is generally produced by fungus.
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Mohan, Vathsala, Reginald Wibisono, Saili Chalke, Graham Fletcher, and Françoise Leroi. "The Anti-Listeria Activity of Pseudomonas fluorescens Isolated from the Horticultural Environment in New Zealand." Pathogens 12, no. 2 (February 19, 2023): 349. http://dx.doi.org/10.3390/pathogens12020349.
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Beneficial bacteria with antibacterial properties are attractive alternatives to chemical-based antibacterial or bactericidal agents. Our study sourced such bacteria from horticultural produce and environments to explore the mechanisms of their antimicrobial properties. Five strains of Pseudomonas fluorescens were studied that possessed antibacterial activity against the pathogen Listeria monocytogenes. The vegetative culture of these strains (Pseudomonas fluorescens-PFR46I06, Pseudomonas fluorescens-PFR46H06, Pseudomonas fluorescens-PFR46H07, Pseudomonas fluorescens-PFR46H08 and Pseudomonas fluorescens-PFR46H09) were tested against Listeria monocytogenes (n = 31), Listeria seeligeri (n = 1) and Listeria innocua (n = 1) isolated from seafood and horticultural sources and from clinical cases (n = 2) using solid media coculture and liquid media coculture. All Listeria strains were inhibited by all strains of P. fluorescens; however, P. fluorescens-PFR46H07, P. fluorescens-PFR46H08 and P. fluorescens-PFR46H09 on solid media showed good inhibition, with average zones of inhibition of 14.8 mm, 15.1 mm and 18.2 mm, respectively, and the other two strains and P. fluorescens-PFR46H09 had a significantly greater zone of inhibition than the others (p < 0.05). There was no inhibition observed in liquid media coculture or in P. fluorescens culture supernatants against Listeria spp. by any of the P. fluorescens strains. Therefore, we hypothesized that the structural apparatus that causes cell-to-cell contact may play a role in the ejection of ant-listeria molecules on solid media to inhibit Listeria isolates, and we investigated the structural protein differences using whole-cell lysate proteomics. We paid special attention to the type VI secretion system (TSS-T6SS) for the transfer of effector proteins or bacteriocins. We found significant differences in the peptide profiles and protein summaries between these isolates’ lysates, and PFR46H06 and PFR46H07 possessed the fewest secretion system structural proteins (12 and 11, respectively), while PFR46H08 and PFR46H09 had 18 each. P. fluorescens-PFR46H09, which showed the highest antimicrobial effect, had nine tss-T6SS structural proteins compared to only four in the other three strains.
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Kjærgaard, Kristian, Mark A. Schembri, Henrik Hasman, and Per Klemm. "Antigen 43 from Escherichia coli Induces Inter- and Intraspecies Cell Aggregation and Changes in Colony Morphology of Pseudomonas fluorescens." Journal of Bacteriology 182, no. 17 (September 1, 2000): 4789–96. http://dx.doi.org/10.1128/jb.182.17.4789-4796.2000.
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ABSTRACT Antigen 43 (Ag43) is a surface-displayed autotransporter protein ofEscherichia coli. By virtue of its self-association characteristics, this protein is able to mediate autoaggregation and flocculation of E. coli cells in static cultures. Additionally, surface display of Ag43 is associated 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 demonstrate that Ag43 can be used as a tool to provide interspecies cell aggregation betweenE. 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 gram-negative bacteria. Display of heterologous Ag43 in selected bacteria might offer opportunities for rational design of multispecies consortia where the concerted action of several bacterial species is required, e.g., waste treatment and degradation of pollutants.
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Gandraburova, N. I., E. I. Kharina, and A. G. Gadzhiahmedova. "EFFECTS OF PSEUDOMONAS FLUORESCENS ON SOME SOIL MICROORGANISMS." Nauka v sovremennom mire 37, no. 4 (2019): 13–17. http://dx.doi.org/10.31618/2524-0935-2019-37-4-13-17.
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Istiqomah, Istiqomah, and Dian Eka Kusumawati. "Pemanfaatan Bacillus subtilis dan Pseudomonas fluorescens dalam pengendalian hayati Ralstonia solanacearum penyebab penyakit layu bakteri pada tomat." Jurnal Agro 5, no. 1 (July 27, 2018): 1–12. http://dx.doi.org/10.15575/2305.
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Salah satu penyakit penting pada produksi tomat di Indonesia adalah layu bakteri yang disebabkan oleh Ralstonia solanacearum. Alternatif untuk mengendalikan penyakit layu bakteri adalah dengan menggunakan Bacillus subtilis dan Pseudomonas fluorescens. Tujuan penelitian ini untuk mengetahui kemampuan B. subtilis dan P. fluorescens dalam mengendalikan penyakit layu bakteri yang disebabkan R. solanacearum serta mekanisme penghambatannya. Penelitian ini terdiri dari 5 tahap, yaitu perbanyakan inokulum R. solanacearum, uji virulensi dan uji hipersensitif R. solanacearum, uji antagonis B. subtilis dan P. fluorescens terhadap R. solanacearum pada media agar, uji jenis antibiosis, penelitian di rumah kaca, dan analisis total fenol. Hasil penelitian uji antagonis menunjukkan bahwa semua isolat B. subtilis dan P. fluorescens memiliki potensi menghambat R. solanacearum dengan tipe antibiosis bakteriostatik. Hasil analisis kadar fenol menunjukkan bahwa terjadi peningkatan total fenol secara signifikan pada tanaman tomat yang diaplikasikan isolat B. subtilis UB-ABS6, P. fluorescens UB-PF5 dan P. fluorescens UB-PF6. Penelitian di rumah kaca menunjukkan bahwa semua tanaman tomat yang diaplikasikan agens hayati mengalami penundaan masa inkubasi dibandingkan dengan kontrol. Isolat B. subtilis UB-ABS2, B. subtilis UB-ABS6, P. fluorescens UB-PF5 dan P. fluorescens UB-PF6 secara signifikan menekan kejadian penyakit layu bakteri berturut-turut 50%, 30%, 60%, dan 60%. B. subtilis dan P. fluorescens dapat dimanfaatkan untuk mengendalikan layu bakteri pada tomat yang disebabkan oleh Ralstonia solanacearum. One of important disease that infects tomato production in Indonesia is bacterial wilt disease caused by Ralstonia solanacearum. Alternative on controlling bacterial wilt is using Bacillus subtilis and Pseudomonas fluorescens. Goal of the research was to find out ability of B. subtilis and P. fluorescens to control R. Solanacearum and mechanism of the inhibition. This research divided into 5 stages, i.e. propagation of R. solanacearum, virulence and hypersensitive tests of R. Solanacearum, antagonist test of B. subtilis and P. fluorescens against R. solanacearum on agar medium, antibiosis type test, research in greenhouse, and total phenol analysis. The result showed that all isolates of B. subtilis and P. fluorescens have potential to inhibite R. solanacearum by bacteriostatic antibiosis type. The total phenol level showed significant increase of phenol on tomato along with the application of isolates B. subtilis UB-ABS6, P. fluorescens UB-PF5 and P. fluorescens UB-PF6. Research in the greenhouse showed that all tomatoes, which had been given bioagent, did delay on the incubation than the control. Isolates of B. subtilis UB-ABS2, B. subtilis UB-ABS6, P. fluorescens UB-PF5, and P. fluorescens UB-PF6 had significantly inhibited the bacterial wilt disease 50%, 30%, 60%, and 60%, respectively. Therefore, B. subtilis and P. fluorescens can be used to control bacterial wilt diseases on tomato caused by Ralstonia solanacearum.
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Lowder, M., A. Unge, N. Maraha, J. K. Jansson, J. Swiggett, and J. D. Oliver. "Effect of Starvation and the Viable-but-Nonculturable State on Green Fluorescent Protein (GFP) Fluorescence in GFP-TaggedPseudomonas fluorescens A506." Applied and Environmental Microbiology 66, no. 8 (August 1, 2000): 3160–65. http://dx.doi.org/10.1128/aem.66.8.3160-3165.2000.
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ABSTRACT The green fluorescent protein (GFP) gene, gfp, of the jellyfish Aequorea victoria is being used as a reporter system for gene expression and as a marker for tracking prokaryotes and eukaryotes. Cells that have been genetically altered with thegfp gene produce a protein that fluoresces when it is excited by UV light. This unique phenotype allowsgfp-tagged cells to be specifically monitored by nondestructive means. In this study we determined whether agfp-tagged strain of Pseudomonas fluorescenscontinued to fluoresce under conditions under which the cells were starved, viable but nonculturable (VBNC), or dead. Epifluorescent microscopy, flow cytometry, and spectrofluorometry were used to measure fluorescence intensity in starved, VBNC, and dead or dying cells. Results obtained by using flow cytometry indicated that microcosms containing VBNC cells, which were obtained by incubation under stress conditions (starvation at 37.5°C), fluoresced at an intensity that was at least 80% of the intensity of nonstressed cultures. Similarly, microcosms containing starved cells incubated at 5 and 30°C had fluorescence intensities that were 90 to 110% of the intensity of nonstressed cells. VBNC cells remained fluorescent during the entire 6-month incubation period. In addition, cells starved at 5 or 30°C remained fluorescent for at least 11 months. Treatment of the cells with UV light or incubation at 39 or 50°C resulted in a loss of GFP from the cells. There was a strong correlation between cell death and leakage of GFP from the cells, although the extent of leakage varied depending on the treatment. Most dead cells were not GFP fluorescent, but a small proportion of the dead cells retained some GFP at a lower concentration than the concentration in live cells. Our results suggest that gfp-tagged cells remain fluorescent following starvation and entry into the VBNC state but that fluorescence is lost when the cells die, presumably because membrane integrity is lost.
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Pradhipta, Hatyanta Nuha, Irianti Kurniasari, and Ugik Romadi. "EFEKTIVITAS PLANT GROWTH PROMOTING RHIZOBACTERIA Pseudomonas fluorescens DALAM PENGENDALIAN HAYATI PENYAKIT BULAI PADA TANAMAN JAGUNG (Zea mays L.)." Agrin 23, no. 1 (April 30, 2019): 45. http://dx.doi.org/10.20884/1.agrin.2019.23.1.427.
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Bulai merupakan penyakit utama pada tanaman jagung yang disebabkan cendawan patogen Peronosclerospora maydis. P. maydis menyebabkan potensi kehilangan hasil mencapai 100%. Berbagai pengendalian yang dilakukan belum memberikan hasil yang optimal dan bahkan menimbulkan dampak negatif terhadap lingkungan dan kesehatan manusia. PGPR Pseudomonas fluorescens diketahui berpotensi sebagai pengendali penyakit bulai yang ramah lingkungan. Penelitian ini bertujuan untuk mengetahui efektivitas P. fluorescens terhadap penekanan penyakit bulai pada tanaman jagung. Penelitian ini menggunakan Rancangan Acak Kelompok (RAK) dengan konsentrasi larutan P. fluorescens sebagai perlakuan terdiri dari: P1=0 ml/L, P2=50 ml/L, P3=75 ml/L, P4=100 ml/L, P5=fungisida fenamidon 50%. Hasil penelitian menunjukan bahwa P. fluorescens dapat efektif mengendalikan penyakit bulai, sedangkan perbedaan konsentrasi P. fluorescens tidak memberikan pengaruh yang signifikan dalam pengendalian penyakit bulai pada tanaman jagung. Kata kunci: Penyakit bulai, PGPR, Pseudomonas fluorescens, tanaman jagung ABSTRACTDowney mildew is the main disease in maize that caused by the fungus pathogen Peronosclerospora maydis. P. maydis caused significant yield loss of up to 100%. The various controls of downey mildew did not bring out succeed and even have a negative impact for the environment and human health. PGPR Pseudomonas fluorescens considered can be used as biological control agents against downy mildew which is environmental friendly. This study aims to determine the effectiveness of P. fluorescens in the controling of downey mildew in maize. Randomized Block Design were used in this research with concentration of P. fluorescens as a treatment consist of: P1 = 0 ml / L, P2 = 50 ml / L, P3 = 75 ml / L, P4 = 100 ml / L, P5 = fenamidone fungicide 50 %. The results showed that P. fluorescens effective to controling of downy mildew, while differences in P. fluorescens concentration has not significant effect for controlling downy mildew in maize. Keywords: Downy Mildew, PGPR, Pseudomonas fluorescens, Maize
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Sruthy M, Sruthy M., and Shivangi S. Kansara. "Evaluation of Bioagents as Seed Treatment on Dominant Seed Mycoflora of Chilli Var. Gvc 111 In Vitro." Current Agriculture Research Journal 10, no. 1 (May 10, 2022): 20–27. http://dx.doi.org/10.12944/carj.10.1.04.
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Study to check the efficacy of seed treatment by bioagents on the seed germination and vigour by inhibiting the most dominant seed mycoflora (A. niger, Colletotrichum sp. and Fusarium sp.) of chilli variety GVC 111 was carried out by paper towel method in vitro. Treatment of seeds with T. harzianum+P. fluorescens (5+6g/kg seeds) and P. fluorescens (6g/kg seeds) found effective in seeds pretreated with A. niger, while T. harzianum+P. fluorescens (5+6g/kg seeds) and P. fluorescens+B. subtilis (6+6g/kg seeds) found effective in seeds pretreated with Colletotrichum sp. and P. fluorescens+B. subtilis (6+6g/kg seeds) and T. viride+P. fluorescens (5+6g/kg seeds) found effective in seeds pretreated with Fusarium sp. However, overall results indicated that seed treatment with P. fluorescens+B. subtilis @ 6g + 6g/kg seeds and T. harzianum+P. fluorescens @ 5g + 6g/kg seeds proved very effective with higher seed germination, seedling length and vigour index in all pretreated seed mycoflora i.e, A. niger. Colletotrichum sp. and Fusarium sp.
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Cui, Xiaohui, and Rob Harling. "Evaluation of Bacterial Antagonists for Biological Control of Broccoli Head Rot Caused by Pseudomonas fluorescens." Phytopathology® 96, no. 4 (April 2006): 408–16. http://dx.doi.org/10.1094/phyto-96-0408.
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Pectolytic strains of Pseudomonas fluorescens are opportunistic pathogens of broccoli, causing head rot in temperate regions of the world. In this study, we investigated the potential of two bacterial isolates, P. fluorescens m6418 and Bacillus sp. A24, for biological control of broccoli head rot caused by P. fluorescens 5064, isolated from diseased broccoli in Scotland, UK. P. fluorescens m6418, a Tn5 mutant of wild-type 5064, is nonpathogenic and overproduces an extracellular metabolite with strong antimicrobial activity. In this study, we identified the anti-microbial metabolite produced by strain m6418 as pyrrolnitrin. P. fluorescens m6418 had significant inhibitory effects against strain 5064 both in culture and on broccoli leaves. In an excised broccoli head pathogenicity test, strain m6418, when coinoculated with P. fluorescens 5064, reduced disease by 41%. Bacillus sp. A24 produces an enzyme that can degrade N-acyl homoserine lactones, signaling molecules employed by bacteria for quorum sensing. Bacillus sp. A24 was capable of out-competing P. fluorescens 5064 when grown together in culture, and could degrade the quorum sensing signal of P. fluorescens 5064 (and thereby attenuate its virulence gene production). However, Bacillus sp. A24 had only a limited biocontrol effect on P. fluorescens 5064 in the excised broccoli head assay.
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Liu, Xuemei, Kieran J. Germaine, David Ryan, and David N. Dowling. "DEVELOPMENT OF A GFP‐BASED BIOSENSOR FOR DETECTING THE BIOAVAILABILITY AND BIODEGRADATION OF POLYCHLORINATED BIPHENYLS (PCBS)." JOURNAL OF ENVIRONMENTAL ENGINEERING AND LANDSCAPE MANAGEMENT 15, no. 4 (December 31, 2007): 261–68. http://dx.doi.org/10.3846/16486897.2007.9636939.
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Two whole-cell biosensors were constructed to detect the in situ biodegradation of polychlorinated biphenyl by chromosomal insertion of a mini‐Tn5‐Kmr‐Pm::gfp[mut3]‐T0‐T1 construct into P. fluorescens. In vitro tests showed that the expression of the Pm promoter depended on the growth phase of the biosensors and the concentration of chemical inducers; chlorinated benzoic acid derivatives. A linear relationship between the fluorescent intensity and the log10 concentration of the inducer was observed. One biosensor (F113L::1180gfp) had the ability to degrade PCBs to relevant chlorobenzoic acid derivatives and to induce expression of Gfp. The second biosensor (F113gfp), which cannot degrade PCBs, shows fluorescence after induction by chloro‐benzoic acid derivatives. By using these two biosensors, PCB degradation could be detected in vitro and in soil.
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FETT, WILLIAM F. "Inhibition of Salmonella enterica by Plant-Associated Pseudomonads In Vitro and on Sprouting Alfalfa Seed†." Journal of Food Protection 69, no. 4 (April 1, 2006): 719–28. http://dx.doi.org/10.4315/0362-028x-69.4.719.
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Foodborne illness due to the consumption of contaminated raw or lightly cooked sprouts is a continuing food safety concern. In this study, we tested several plant-associated pseudomonads for their ability to inhibit the growth of Salmonella enterica both in vitro and in situ. An agar spot bioassay method was used with three different media. Only Pseudomonas fluorescens 2-79 produced clear zones of inhibition when tested against five serovars of S. enterica, and activity was dependent on media type and serovar. The antibiosis by derivative strains of P. fluorescens 2-79 defective in the production of phenazine-1-carboxylic acid and fluorescent siderophore was not reduced, indicating that these known antimicrobial metabolites were not responsible for the inhibition observed in our studies. However, mutants defective in the regulatory gene gacS (global antibiotic and cyanide control) were severely reduced in inhibitory activity. In tryptic soy broth, the control cultures of a cocktail of S. enterica strains reached approximately 10 log CFU/ml by 24 h but, when coinoculated with P. fluorescens 2-79, reached only approximately 5 log CFU/ml. The addition of P. fluorescens 2-79 to the seed soak water prior to the germination of alfalfa seed previously inoculated with a cocktail of S. enterica strains led to an average reduction of 5 log CFU/g at 6 days of sprouting without an adverse effect on sprout yield or appearance. Time course studies indicated that S. enterica outgrowth was controlled on days 1 through 6 of sprouting. Competitive exclusion as a potential food safety intervention for seed sprouts merits further study.
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Fabia, Benedict-Uy, Joshua Bingwa, Jiyeon Park, Nguyen-Mihn Hieu, and Jung-Hoon Ahn. "Utilizing the ABC Transporter for Growth Factor Production by fleQ Deletion Mutant of Pseudomonas fluorescens." Biomedicines 9, no. 6 (June 16, 2021): 679. http://dx.doi.org/10.3390/biomedicines9060679.
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Pseudomonas fluorescens, a gram-negative bacterium, has been proven to be a capable protein manufacturing factory (PMF). Utilizing its ATP-binding cassette (ABC) transporter, a type I secretion system, P. fluorescens has successfully produced recombinant proteins. However, besides the target proteins, P. fluorescens also secretes unnecessary background proteins that complicate protein purification and other downstream processes. One of the background proteins produced in large amounts is FliC, a flagellin protein. In this study, the master regulator of flagella gene expression, fleQ, was deleted from P. fluorescens Δtp, a lipase and protease double-deletion mutant, via targeted gene knockout. FleQ directs flagella synthesis, so the new strain, P. fluorescens ΔfleQ, does not produce flagella-related proteins. This not only simplifies purification but also makes P. fluorescens ΔfleQ an eco-friendly expression host because it will not survive outside a controlled environment. Six recombinant growth factors, namely, insulin-like growth factors I and II, beta-nerve growth factor, fibroblast growth factor 1, transforming growth factor beta, and tumor necrosis factor beta, prepared using our supercharging method, were successfully secreted by P. fluorescens ΔfleQ. Our findings demonstrate the potential of P. fluorescens ΔfleQ, combined with our supercharging process, as a PMF.
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Idei, Akiko, Eri Kawai, Hiroyuki Akatsuka, and Kenji Omori. "Cloning and Characterization of thePseudomonas fluorescens ATP-Binding Cassette Exporter, HasDEF, for the Heme Acquisition Protein HasA." Journal of Bacteriology 181, no. 24 (December 15, 1999): 7545–51. http://dx.doi.org/10.1128/jb.181.24.7545-7551.1999.
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ABSTRACT Two ATP-binding cassette (ABC) exporters are present inPseudomonas fluorescens no. 33; one is the recently reported AprDEF system and the other is HasDEF, which exports a heme acquisition protein, HasA. The hasDEF genes were cloned by DNA hybridization with a DNA probe coding for the LipB protein, one of the components of the Serratia marcescens ABC exporter Lip system. P. fluorescens HasA showed sequence identity of 40 to 49% with HasA proteins from Pseudomonas aeruginosa andSerratia marcescens. The P. fluorescens Has exporter secreted HasA proteins from P. fluorescens andP. aeruginosa but not S. marcescens HasA inEscherichia coli, whereas the Has exporter from S. marcescens allowed secretion of all three HasA proteins. TheP. fluorescens HasDEF system also promoted the secretion of the lipase and alkaline protease of P. fluorescens. Hybrid exporter analysis demonstrated that the HasD proteins, which are ABC proteins, are involved in the discrimination of export substrates. Chimeric HasA proteins containing both P. fluorescens andS. marcescens sequences were produced and tested for secretion through the Has exporters. The C-terminal region of HasA was shown to be involved in the secretion specificity of the P. fluorescens Has exporter.
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Srivastava, Alok K., Tanuja Singh, T. K. Jana, and Dilip K. Arora. "Induced resistance and control of charcoal rot in Cicer arietinum (chickpea) by Pseudomonas fluorescens." Canadian Journal of Botany 79, no. 7 (July 1, 2001): 787–95. http://dx.doi.org/10.1139/b01-054.
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Pseudomonas fluorescens isolate 4-92 induced systemic resistance against charcoal rot disease in chickpea (Cicer arietinum L.) caused by Macrophomina phaseolina (Tassi) Goidanich. Time-course accumulation of pathogenesis-related (PR) proteins (chitinases and glucanases) in chickpea plants inoculated with P. fluorescens was significantly (P = 0.05) higher than in control plants. The level of chitinases and glucanases increased by 6.6- to 7-fold up to 4 days postinoculation; thereafter, little decrease in the activity of PR proteins was observed. Root-colonizing populations of P. fluorescens were at a maximum 2 days after transplantation at different inoculum concentrations, and decreased over time. Inoculation of root tips of chickpea by P. fluorescens, 2,6-dichloroisonicotinic acid, and o-acetylsalicylic acid induced systemic resistance against charcoal rot. Disease was 33 to 55.5% higher in control plants than in plants inoculated with chemical inducers or P. fluorescens. Single treatment of plants with P. fluorescens increased disease resistance by 33%, whereas combined application of P. fluorescens with either of the chemical inducers was most effective in inducing the resistance by 2- to 2.25-fold. The time-course study shows that an interval of at least 2 days was required between induction treatment and challenge inoculation. Biocontrol efficacy of P. fluorescens against charcoal rot disease in chickpea was demonstrated under greenhouse conditions.Key words: biological control, induced resistance, Macrophomina phaseolina, Pseudomonas fluorescens.
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Wang, Zhirong, Mengyao Jiang, Kewei Chen, Kaituo Wang, Muying Du, Zsolt Zalán, Ferenc Hegyi, and Jianquan Kan. "Biocontrol of Penicillium digitatum on Postharvest Citrus Fruits by Pseudomonas fluorescens." Journal of Food Quality 2018 (November 14, 2018): 1–10. http://dx.doi.org/10.1155/2018/2910481.
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The effectiveness of the bacteria antagonist Pseudomonas fluorescens to control green mold caused by Penicillium digitatum on oranges (Citrus sinensis Osbeck, cv. Jincheng) and the possible modes of action were evaluated. Whether in vitro or in vivo, treatments with cell-free autoclaved cultures or culture filtrate had limited capacity to suppress P. digitatum, while P. digitatum was significantly inhibited by bacterial fluid (P. fluorescens in the nutrient broth liquid medium) and bacterial suspension (P. fluorescens in sterile distilled water) with living cells. There was a positive relationship between the concentration of P. fluorescens in bacterial suspension and its biological efficacy. In addition, P. fluorescens was effective when applied preventatively but not when applied curatively. In the inoculated wounds, the population of P. fluorescens was an approximately 28- and 34-fold increase after being incubated at 20°C for 8 d and at 4°C for 16 d, respectively, and P. digitatum could effectively stimulate the growth and reproduction of P. fluorescens. Moreover, P. fluorescens was able to inhibit spore germination and germ tube elongation of P. digitatum as well as induce resistance on citrus peel by increasing the chitinase (CHI) activity and advancing the activities peaks of β-1,3-glucanase (GLU), peroxidase (POD), and phenylalanine ammonia lyase (PAL). All of these results support the potential application of P. fluorescens against green mold on postharvest citrus.
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HU, LIANXIA, SHUFEI ZHANG, YULING XUE, JUNHUA HAN, HUAXI YI, YUEHUA KE, YONGJUN XIA, and SHIJIE WANG. "Rapid Identification of Pseudomonas fluorescens Harboring Thermostable Alkaline Protease by Real-Time Loop-Mediated Isothermal Amplification." Journal of Food Protection 85, no. 3 (December 2, 2021): 414–23. http://dx.doi.org/10.4315/jfp-21-272.
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ABSTRACT Thermostable alkaline protease (TAP) harbored by Pseudomonas fluorescens decomposes protein in milk and dairy products, leading to milk and dairy product spoilage during storage. Thus, a specific, sensitive, rapid, and simple method is required to detect TAP-harboring P. fluorescens. Two sets of primers targeting the aprX and gyrB genes of P. fluorescens were designed. The detection system and conditions were optimized, and a real-time loop-mediated isothermal amplification (real-time LAMP) method was developed for the simultaneous detection of TAP-harboring P. fluorescens in two separate reaction tubes. The phylogenetic tree targeting aprX showed that P. fluorescens and Pseudomonas lurida clustered on the same branch. The phylogenetic tree targeting gyrB showed that P. fluorescens clustered on the same branch with 95% confidence value, whereas P. lurida clustered on different branches. DNA of 16 strains of P. fluorescens and 34 strains of non–P. fluorescens was detected by real-time LAMP. TAP-harboring P. fluorescens can only be identified when the real-time LAMP detection results of both aprX and gyrB are positive. The dissociation temperatures of aprX and gyrB in the real-time LAMP–amplified products were approximately 90.0 and 88.0°C, respectively. The detection limits of the real-time LAMP targeting aprX and gyrB were 4.9 CFU per reaction in pure culture and 2.2 CFU per reaction in skimmed milk. The coefficient of variation of the repeatability test was less than 2%, indicating that the established real-time LAMP of P. fluorescens targeting gyrB and aprX has good stability and repeatability. Real-time LAMP was used to test 200 raw milk samples for the presence of TAP-harboring P. fluorescens in 3 h, and the coincidence rate of the results with those obtained using the traditional method, which takes at least 5 to 7 days, was 100%. Real-time LAMP will be a practical and effective method for accurate and rapid identification of TAP-harboring P. fluorescens in raw milk. HIGHLIGHTS
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Moynihan, Jennifer A., John P. Morrissey, Eric R. Coppoolse, Willem J. Stiekema, Fergal O'Gara, and E. Fidelma Boyd. "Evolutionary History of the phl Gene Cluster in the Plant-Associated Bacterium Pseudomonas fluorescens." Applied and Environmental Microbiology 75, no. 7 (January 30, 2009): 2122–31. http://dx.doi.org/10.1128/aem.02052-08.
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ABSTRACT 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, has antimicrobial effects on phytopathogens, promotes amino acid exudation from plant roots, and induces systemic resistance in plants. Despite its importance, 2,4-DAPG production is limited to a subset of P. fluorescens strains. Determination of the evolution of the phl cluster and understanding the selective pressures promoting its retention or loss in lineages of P. fluorescens will help in the development of P. fluorescens as a viable and effective inoculant for application in agriculture. In this study, genomic and sequence-based approaches were integrated to reconstruct the phylogeny of P. fluorescens and the phl cluster. It was determined that 2,4-DAPG production is an ancestral trait in the species P. fluorescens but that most lineages have lost this capacity through evolution. Furthermore, intragenomic recombination has relocated the phl cluster within the P. fluorescens genome at least three times, but the integrity of the cluster has always been maintained. The possible evolutionary and functional implications for retention of the phl cluster and 2,4-DAPG production in some lineages of P. fluorescens are discussed.
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R, Vimala, and Suriachandraselvan M. "INFLUENCE OF ANTAGONISTIC AGENT, PLANT PRODUCTS AND CHEMICAL AGENTS ON THE POWDERY MILDEW DISEASE OF BHENDI AND ITS PRODUCTION." Journal of Biopesticides 1, no. 2 (December 1, 2008): 130–33. http://dx.doi.org/10.57182/jbiopestic.1.2.130-133.
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Field investigations were made to study the influence of integrated disease management involving plant products and biological control agents of powdery mildew of Bhendi (Erysiphe cichoracearum DC) with ten treatments viz.,Pseudomonas fluorescens I18 (0.2%), P.fluorescens 1(0.2%), Ocimum sanctum 10%, Neem Seed Kernel Extract 5%, K2 HPO4 50 mM, Salicylic acid 1mM, O. sanctum 5% + P. fluorescens I18 (0.2%),Neem Seed Kernel Extract 5 % + P.fluorescens I18 (0.2%), Carbendazim 0.1% and Control. Two sprays were given; first one on 30 days after sowing and the second one on 60 days after sowing. Powdery mildew disease severity was recorded at weekly interval after the second spray on randomly selected plants based on 0-5 grade scale and PDI was calculated. At the end of the season, yield was recorded in each plot. The minimum disease incidence of 8.83% was recorded with Neem Seed Kernel Extract 5%+ Pseudomonas fluorescens I18 0.2% followed by 9.49% with Pseudomonas fluorescens I18 0.2%,10.36% with carbendazim and 11.9% with Pseudomonas fluorescens -1.The yield was also increased to the tune of 43.43% over control in NSKE 5%+Pseudomonas fluorescens I18 followed by 42.44% in Pseudomonas fluorescens I18 ,41.84% with 0.1% carbendazim and 39.73% with Pseudomonas fluorescens -1.
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Matondang, Christina Oktora, Muklasin, and Loekas Soesanto. "Potensi ekstrak kasar metabolit sekunder yang dihasilkan Trichoderma asperellum dan Pseudomonas fluorescens untuk pengendalian antraknosa pada buah kakao." E-Journal Menara Perkebunan 91, no. 1 (April 29, 2023): 87–95. http://dx.doi.org/10.22302/iribb.jur.mp.v91i1.524.
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Cocoa pod anthracnose is an important disease of cocoa and can reduce yields. Many attempts have been made to control anthracnose rot disease on cocoa pods but have not been successful yet. This study aimed to examine the potency of secondary metabolite crude extracts produced by Trichoderma asperellum and Pseudomonas fluorescens solely or in combination in controlling anthracnose rot disease of cocoa pods in the field at Silo Bonto Village, Asahan Regency, North Sumatera Province. The secondary metabolite crude extracts was prepared by the form of conidia or T. asperellum and P. fluorescens cells. A randomized block design was used to assessed four treatments i.e. T. asperellum + P. fluorescens, T. asperellum, P. fluorescens secondary metabolite crude extracts and control, which was repeated six times. The observation parameters were the percentage of healthy and diseased pods (anthracnose fruit rot). The results showed that the secondary metabolite crude extracts of T. asperellum, P. fluorescens, and T. asperellum + P. fluorescens reduced the number of diseased fruits by 94.71, 89.09, and 92.09% compared to the control respectively. The increasing of healthy fruits number in the application of secondary metabolite crude extracts of T. asperellum, P. fluorescens, and T. asperellum + P. fluorescens was 52.68, 54.20, and 54.18%, respectively.
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Anderson, Mark, and Richard Davey. "Pseudobacteraemia with Pseudomonas fluorescens." Medical Journal of Australia 160, no. 4 (February 1994): 233–34. http://dx.doi.org/10.5694/j.1326-5377.1994.tb126622.x.
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Asm, Hisae, Hiromichi Onozaki, and Hidemasa Imaseki. "Vanillylamine Metabolism inPseudomonas fluorescens." Agricultural and Biological Chemistry 52, no. 11 (November 1988): 2741–46. http://dx.doi.org/10.1080/00021369.1988.10869155.
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Lejeune, André, Charles Colson, and Douglas E. Eveleigh. "Cloning of an endoglucanase gene fromPseudomonas fluorescens var.cellulosa intoEscherichia coli andPseudomonas fluorescens." Journal of Industrial Microbiology 1, no. 2 (June 1986): 79–86. http://dx.doi.org/10.1007/bf01569315.
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FARRAG, SEHAM A., and ELMER H. MARTH. "Growth of Listeria monocytogenes in the Presence of Pseudomonas fluorescens at 7 or 13°C in Skim Milk." Journal of Food Protection 52, no. 12 (December 1, 1989): 852–55. http://dx.doi.org/10.4315/0362-028x-52.12.852.
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Autoclaved samples of skim milk were inoculated with Listeria monocytogenes (strain Scott A, California or V7), Pseudomonas fluorescens (strain P26 or B52), or a combination of L. monocytogenes plus P. fluorescens, and incubated at 7 or 13°C for 8 weeks. McBride Listeria Agar was used to determine populations of L. monocytogenes (at 0, 7, 14, 28, 42, or 56 d), and Pseudomonas isolation agar to enumerate P. fluorescens. Growth of L. monocytogenes was somewhat enhanced after 7 d of incubation at 7 but not at 13°C in the presence of pseudomonads. However, after 14 d and until the end of the incubation period (56 d), slight inactivation of L. monocytogenes in the presence of P. fluorescens was observed. L. monocytogenes did not affect growth or survival of P. fluorescens; also, no marked changes in pH of the milk were caused either by L. monocytogenes alone or by L. monocytogenes plus P. fluorescens.
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Gangwar, Gokil Prasad, and A. P. Sinha. "Effect of fungal and bacterial bioagent application on total phenolic content in rice leaves pre-inoculated with Xanthomonas oryzae pv. oryzae (Uyeda and Ishiyama) Dowson." Journal of Applied and Natural Science 6, no. 1 (June 1, 2014): 254–57. http://dx.doi.org/10.31018/jans.v6i1.410.
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Present study was carried out to observe the effect of fungal and bacterial bioagents on total phenolic content in rice leaves pre-inoculated with Xanthomonas oryzae pv. oryzae and on disease severity of bacterial leaf blight of rice. Two commercial formulations of Trichoderma harzianum (PBA-1) and Pseudomonas fluorescens (PBA-2) and four formulations of fluorescent pseudomonads and Trichoderma spp. viz, P. fluorescens (Pf 83, rice leaf isolate), fluorescent pseudomonad (FLP 88, rice leaf isolate), T. harzianum (rice leaf isolate), Trichoderma spp. (isolate 40, isolated from rice field soil) were evaluated. Significantly higher mean value of total phenolic content of rice leaves was observed with the application of bioagent formulations as compared to check (pre-inoculated with X. oryzae pv. oryzae), chemical treatment and healthy plant. Maximum mean total phenolic content (342.22 μl/g) in rice leaves was observed with Pf 83, which was followed by PBA-2 (334.44 μl/g) and T. harzianum (330.00 μl/g). Decrease in disease severity of bacterial leaf blight was observed with the increase of total phenolic content in rice leaves which resulted in increased grain yield and 1000 grain weight.
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Ulhaq, Muhamad Aditia, and Rachmi Masnilah. "Pengaruh Penggunaan Beberapa Varietas dan Aplikasi Pseudomonas fluorescens untuk Mengendalikan Penyakit Bulai (Peronosclerospora maydis) pada Tanaman Jagung (Zea mays L.)." Jurnal Pengendalian Hayati 2, no. 1 (March 18, 2019): 1. http://dx.doi.org/10.19184/jph.v2i1.17131.
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Corn is one of the commodities that have high economic value and important role in meeting food needs in Indonesia. Unfavorable conditions on the rate of the higher demand for corn. Pests to be one limiting factor that causes a decrease in the production of corn. Peronosclerospora maydis is a pathogen that causes downy mildew on corn. P. maydis infects corn plants at the age of 2-3 weeks, with the level of damage reaches 80-100%. Control efforts against this disease one of them using antagonistic microbes such as bacteria Pseudomonas fluorescens. P. fluorescens has the potential to control downy mildew because it produces compounds that are antibiosis as chitinase enzymes that can hydrolyze the cell walls of fungi. The purpose of this study to determine the effect of the interaction of P. fluorescens isolates applications and the use of some varieties to suppress downy mildew attack P. maydis on corn. The method used is to use a random test design of a factorial group with 2 factors. The first factor is the type of varieties with three levels namely V1: Pioneer 27, V2: Pioneer 21 and V3: Bonanza. The second factor is a type of isolates P. fluorescens with three levels namely P1: without the application of P. fluorescens, P2: Isolates P. fluorescens (A) and P3: Isolate of P. fluorescens (B). The result is the application of P. fluorescens and use of some varieties can suppress downy mildew P. maydis.
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Bellassi, Paolo, Gabriele Rocchetti, Lorenzo Morelli, Biancamaria Senizza, Luigi Lucini, and Fabrizio Cappa. "A Milk Foodomics Investigation into the Effect of Pseudomonas fluorescens Growth under Cold Chain Conditions." Foods 10, no. 6 (May 24, 2021): 1173. http://dx.doi.org/10.3390/foods10061173.
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Pseudomonas fluorescens is a psychrotrophic species associated with milk spoilage because of its lipolytic and proteolytic activities. Consequently, monitoring P. fluorescens or its antecedent activity in milk is critical to preventing quality defects of the product and minimizing food waste. Therefore, in this study, untargeted metabolomics and peptidomics were used to identify the changes in milk related to P. fluorescens activity by simulating the low-temperature conditions usually found in milk during the cold chain. Both unsupervised and supervised multivariate statistical approaches showed a clear effect caused by the P. fluorescens inoculation on milk samples. Our results showed that the levels of phosphatidylglycerophosphates and glycerophospholipids were directly related to the level of contamination. In addition, our metabolomic approach allowed us to detect lipid and protein degradation products that were directly correlated with the degradative metabolism of P. fluorescens. Peptidomics corroborated the proteolytic propensity of P. fluorescens-contaminated milk, but with lower sensitivity. The results obtained from this study provide insights into the alterations related to P. fluorescens 39 contamination, both pre and post heat treatment. This approach could represent a potential tool to retrospectively understand the actual quality of milk under cold chain storage conditions, either before or after heat treatments.
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CHAN, WENDY K. M., SEON-TEA JOO, CAMERON FAUSTMAN, QUN SUN, and ROBERT VIETH. "Effect of Pseudomonas fluorescens on Beef Discoloration and Oxymyoglobin Oxidation In Vitro†." Journal of Food Protection 61, no. 10 (October 1, 1998): 1341–46. http://dx.doi.org/10.4315/0362-028x-61.10.1341.
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The relationship between bacterial growth and oxymyoglobin oxidation in vitro and in meat was studied. In the in vitro study, oxymyoglobin was combined with Pseudomonas fluorescens or sterile nutrient broth (control) in an airtight vessel. P. fluorescens samples showed greater metmyoglobin formation and oxygen consumption than controls. The P. fluorescens population in the reaction vessels was correlated with metmyoglobin formation (r = 0.85, P < 0.05) and oxygen consumption (r = 0.91, P < 0.05). When P. fluorescens and oxymyoglobin were combined in an airtight vessel, reducing the headspace from 13 ml and 9 ml to 3 ml resulted in greater metmyoglobin formation (P < 0.05). In the meat study, beef cores prepared from longissimus lumborum were inoculated with P. fluorescens (107 CFU/cm2) or sterile peptone water (control), packaged under 1 % O2 (+99% N2), air, or 100% O2 and stored at 4°C. Inoculated beef cores showed higher bacterial loads and metmyoglobin formation than their respective Controls during 10 h storage in 1% O2, 3 days in air, and 7 days in 100% O2 (P < 0.05). This finding indicated that P. fluorescens could accelerate beef discoloration. Overall, studies demonstrated that oxygen consumption concomitant with P. fluorescens growth decreased partial oxygen pressure, which accelerated oxymyoglobin oxidation.
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Mudi, La, Andi Bahrun, and Gusti Ayu Kade Sutariati. "Bio-Priming Benih Menggunakan Campuran Rizobakter Indigenous untuk meningkatkan Kualitas Fisiologis Benih Kedelai (Glycine max L. Merril)." Berkala Penelitian Agronomi 5, no. 2 (July 2, 2019): 1. http://dx.doi.org/10.33772/bpa.v6i1.7508.
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Penelitian ini bertujuan untuk mempelajari efektivitas bio-priming benih menggunakan campuaran rizobakter indigenous untuk meningkatkan kualitas fisiologis benih kedelai. Penelitian telah dilakukan pada Bulan November 2014 sampai dengan Januari 2015 di Laboratorium Agroteknologi Fakultas Pertanian Universitas Halu Oleo. Penelitian ini dilaksanakan menggunakan Rancangan Acak Lengkap (RAL) factor tunggal yang terdiri dari delapan perlakuan yaitu: control (tanpa perlakuan rizobakter), bio-priming menggunakan Bacillus sp. CKD061, bio-priming menggunakan P. fluorescens PG01, bio-priming menggunakan Serratia sp. CMN175, bio-priming menggunakan campuran Bacillus sp. CKD061 + P. fluorescens PG01, bio-priming menggunakan campuran Bacillus sp. CKD061 + Serratia sp. CMN175, bio-priming menggunakan campuran P. fluorescens PG01 + Serratia sp. CMN175 dan bio-priming menggunakan campuran Bacillus sp. CKD061 + P. fluorescens PG01 + Serratia sp. CMN175. Setiap perlakuan diulang sebanyak tiga kali sehingga seluruhnya terdiri dari 24 unit percobaan. Data hasil penelitian dianalisis ragam dengan uji lanjut Duncan’s Multiple Range Test (DMRT). Hasil pengamatan pengujian fisiologis benih menunjukkan bahwa bio-priming menggunakan campuran Bacillus sp. CKD061 + P. fluorescens PG01 meningkatkan kualitas fisiologis benih. Bio-priming benih menggunakan campuran Bacillus sp. CKD061 + P. fluorescens PG01 memberikan hasil yang lebih baik dalam meningkatkan viabilitas dan vigor benih kedelai.Keywords: Bacillus sp. CKD061 + P. fluorescens PG01, bio-priming benih, campuran rizobakter, kualitas fisiologis benih, rizobakter Indigenous,
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Rajeswari, T., B. Elayarajah, B. Venkatrajah, S. Rajakumar, Vijayaraghavan R, and R. Vijayaraghavan. "Biodegradation of Petroleum Hydrocarbon Using Pseudomonas and Its Antifungal Activity against Phytopathogens." Bangladesh Journal of Scientific and Industrial Research 46, no. 3 (November 27, 2011): 297–302. http://dx.doi.org/10.3329/bjsir.v46i3.3858.
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Fluorescent Pseudomonas isolated from oil-spilled soil were studied for the degradation of oil (Commercially available 2T oil) sample by growing in Bushnell Hass medium. The hydrocarbon degradation was measured calorimetrically in the basal media based on the turbidity. The degraded oil sample was utilized for studying its efficiency in Phaseolus aureus seeds germination. The thin layer chromatographic technique differentiates the specific components of antifungal metabolites and was isolated by centrifugation technique showed the Rf value of about 0.34. Antagonistic potential of these metabolites were demonstrated by agar diffusion method and spot inoculation method. The present study thus demonstrated the ability of the isolated Pseudomanas fluorescens to utilize crude oil in liquid media and to compete with indigenous soil microorganisms, enhance crude oil degradation and reduces its phytotoxicity.Key words: Biodegradation; Petroleum hydrocarbons; Pseudomanas fluorescens; Phytopathogen; Antifungal activityDOI: http://dx.doi.org/10.3329/bjsir.v46i3.3858 BJSIR 2011; 46(3): 297-302
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Hameed, Hussein M., Faiq H. Ali, and Maytham A. Makki. "The Effect of Pseudomonas fluorescens and Salicylic Acid, and their Synergistic Effect on Protein, Carbohydrates Content and Leaf Area of Two Varieties of Triticum aestivum L. Plant." INTERNATIONAL JOURNAL OF DRUG DELIVERY TECHNOLOGY 12, no. 02 (June 25, 2022): 662–65. http://dx.doi.org/10.25258/ijddt.12.2.34.
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The study aims to show the effect of salicylic acid at concertation (50–100 and 150 ppm) and Pseudomonas fluorescens at (105,106,107 cfu/mL) on protein, carbohydrates content and leaf area for two varieties (Abu-Ghraib, Abaa 99) of Triticum aestivum L. The results are indicated the significant effect of P. fluorescens and salicylic acid (SA) at the combination of concentration of P. fluorescens (FP2) and SA (SA2) for variety (Abu-Ghraib) was more impact than (Abaa 99) on the physiological aspect like protein, carbohydrates content and leaf area (7.427, 55.55, 26.42) mg/g dry weight respectively while the value of control was (0.969, 4.158, 4.100) mg/g, respectively. The results showed that salicylic acid and P. fluorescens induced better than the sole application of SA or P. fluorescens.
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Edy Santoso, Suprapto, Loekas Soesanto, and Totok Agung Dwi Haryanto. "PENEKANAN HAYATI PENYAKIT MOLER PADA BAWANG MERAH DENGAN TRICHODERMA HARZIANUM, TRICHODERMA KONINGII, DAN PSEUDOMONAS FLUORESCENS P60." Jurnal Hama dan Penyakit Tumbuhan Tropika 7, no. 1 (March 4, 2007): 53–61. http://dx.doi.org/10.23960/j.hptt.1753-61.
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Biological Suppression of Moler Disease on Shallot by Trichoderma harzianum, Trichoderma koningii, and Pseudomonas fluorescens P60. Research aiming for (1) knowing efectivity of biological suppression with T. harzianum, T. koningii, and P. fluorescens P60 and (2) studying growth and production of shallot caused by the suppression carried out at the shallot farm. Split-Split Plot Design arranged in Randomized Completely Block Design was used with three replicates. The research result showed that P. fluorescens P60 was the most effective antagonistic agent to suppress the disease either alone or in combination while T. harzianumi and T. koningii did not suppress effectively. Pseudomonas fluorescens P60 could suppress the disease up to 41.96%. The best method of P. fluorescens P60 application was spraying method for 10 mL with 107 cfu/mL population density, which was able to dicrease incubation period, disease intensity, and final pathogen population up to 62.46, 18.19, and 80.67%, respectively. Growth and production of the crop tended to increase resulted from biological suppression by P. fluorescens P60, but not by T. harzianum nor T. koningii.
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Chapalain, A., G. Rossignol, O. Lesouhaitier, A. Merieau, C. Gruffaz, J. Guerillon, J. M. Meyer, N. Orange, and M. G. J. Feuilloley. "Comparative study of 7 fluorescent pseudomonad clinical isolates." Canadian Journal of Microbiology 54, no. 1 (January 2008): 19–27. http://dx.doi.org/10.1139/w07-110.
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There is some debate about the potential survival of Pseudomonas fluorescens at temperatures above 37 °C and its consequences for infectious potential, owing to the heterogeneity of clinical strains. Seven clinical strains growing at 37 °C or more were submitted for polyphasic identification; 2 were identified as Pseudomonas mosselii and 4 were precisely characterized as P. fluorescens bv. I or II. The binding indexes on glial cells of the strains identified as P. fluorescens bv. I and P. mosselii were compared with that of a reference psychrotrophic strain, P. fluorescens MF37 (bv. V). Clinical P. fluorescens had a similar adherence potential range than strain MF37. Conversely, the binding indexes for P. mosselii strains were 3 times greater than that for strain MF37. These data, and those obtained by comparing the cytotoxic activities of P. fluorescens clinical strains, suggest the existence of different virulence mechanisms, leading either to a low infectious form or to a microorganism with cytotoxic activity in the same range as that of P. mosselii or even Pseudomonas aeruginosa .