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International Journal of Food... Mar 2021Since Pseudomonas fluorescens is the main microorganism causing severe spoilage in refrigerated aquatic products, the searching for non-antibiotic antibacterial agents...
Since Pseudomonas fluorescens is the main microorganism causing severe spoilage in refrigerated aquatic products, the searching for non-antibiotic antibacterial agents effective against it continues to receive increasing interest. This study aimed to investigate the antibacterial effects and mechanisms of alkyl gallic esters against P. fluorescens isolated from the Russian sturgeon (Acipenser gueldenstaedti), as well as the effectiveness in combination with chitosan films on the preservation of sturgeon meats at 4 °C. Our data shows that the alkyl chain length plays a significant role in eliciting their antibacterial activities and octyl gallate (GAC8) exhibited an outstanding inhibitory efficacy. GAC8 can rapidly enter into the membrane lipid bilayer portion to disorder the membrane, and further inhibit the growth of the P. fluorescens through interfering both tricarboxylic acid cycle related to energy supply and amino acid metabolism associated with cell membranes, suppressing oxygen consumption and disturbing the respiration chain. Moreover, the alteration in membrane fatty acids indicated that GAC8 could disrupt the composition of cell membrane fatty acids, rendering the bacteria more sensitive to the antibacterial. The SEM results also substantiate the damage of the structure of the bacterial membrane caused by GAC8. Additionally, the edible chitosan-based films incorporated with GAC8 showed the enhanced antibacterial efficacy to remarkably extend the shelf life of Russian sturgeon. Overall, our findings not only provide new insight into the mode of action of GAC8 against P. fluorescens but also demonstrate composite films containing GAC8, as a kind of safe and antibacterial material, have a great promise for application in food preservations.
Topics: Animals; Anti-Bacterial Agents; Cell Membrane; Chitosan; Edible Films; Energy Metabolism; Fishes; Food Preservation; Gallic Acid; Pseudomonas fluorescens
PubMed: 33607540
DOI: 10.1016/j.ijfoodmicro.2021.109093 -
Scandinavian Journal of Infectious... 2006Pseudomonas fluorescens was isolated from an elderly immunocompromized patient with fever. Treatment with ceftazidime was successful, after empirical therapy failed....
Pseudomonas fluorescens was isolated from an elderly immunocompromized patient with fever. Treatment with ceftazidime was successful, after empirical therapy failed. Pseudomonas fluorescens is 1 of the less virulent members of the Pseudomonadaceae family. The epidemiology of the infection and the difficulties in isolation and susceptibility assessment are further discussed.
Topics: Aged, 80 and over; Anti-Bacterial Agents; Gram-Negative Bacterial Infections; Humans; Pseudomonas fluorescens
PubMed: 16338843
DOI: 10.1080/00365540500264043 -
Applied Microbiology Jan 1973Strains of Pseudomonas producing fluorescin but no pyocyanin or pyorubrin were studied by biochemical and antibiotic sensitivity testing. A rapid nitrate test was found...
Strains of Pseudomonas producing fluorescin but no pyocyanin or pyorubrin were studied by biochemical and antibiotic sensitivity testing. A rapid nitrate test was found to be useful in distinguishing P. aeruginosa (positive) from P. fluorescens and P. putida (both negative). A shortened gelatin test differentiated P. fluorescens (positive) from P. putida (negative). P. fluorescens and P. putida were very sensitive to low levels of kanamycin and resistant to carbenicillin, a pattern just the opposite of that obtained with P. aeruginosa.
Topics: Anti-Bacterial Agents; Bacteriological Techniques; Carbenicillin; Gelatin; Kanamycin; Nitrates; Penicillin Resistance; Pigments, Biological; Pseudomonas; Pseudomonas fluorescens; Species Specificity
PubMed: 4631431
DOI: 10.1128/am.25.1.107-110.1973 -
Archives of Biochemistry and Biophysics Feb 2014The kynurenine pathway is the major pathway of l-tryptophan catabolism in eukaryotes and some bacteria. In this pathway, kynureninase catalyzes the hydrolysis of... (Review)
Review
The kynurenine pathway is the major pathway of l-tryptophan catabolism in eukaryotes and some bacteria. In this pathway, kynureninase catalyzes the hydrolysis of l-kynurenine (in bacteria) or 3-hydroxy-l-kynurenine (in eukaryotes) to give anthranilic acid or 3-hydroxyanthranilic acid, respectively, and l-alanine. Kynureninase is a member of the aminotransferase superfamily and contains pyridoxal-5'-phosphate (PLP) as cofactor. The enzyme is a dimer of two identical subunits, with the active site containing residues contributed from both subunits. The reaction of kynureninase is formally a retro-Claisen reaction, and thus requires extensive acid-base catalysis. The pH dependence of the reaction of Pseudomonas fluorescens kynureninase shows two pKa's, a base with 6.5 and an acid with 8.8, on kcat/Km, and one pKa of 6.8 on kcat. The effects of mutagenesis of Tyr-226 and (31)P NMR results suggest that the basic group with pKa of 6.5 is the phosphate group of the PLP, which accepts a proton from the amino acid substrate zwitterion to initiate transaldimination. The external aldimine of kynurenine and PLP is then deprotonated by the ε-amino group of Lys-227 to give a quinonoid intermediate, which is reprotonated at C-4' to give a ketimine. Addition of water to the γ-carbonyl, assisted by Lys-227, then gives a gem-diol, which undergoes Cβ-Cγ cleavage to give the first product, anthranilic acid, and an enamine intermediate. The enamine is protonated at the β-carbon, resulting in a pyruvate ketimine. Deprotonation at C-4' and reprotonation of the α-carbon gives the external aldimine of l-alanine, which releases the second product, l-alanine. The reaction specificity of kynureninases is determined in part by active site residues, Trp64, Gly281, and Thr282 in P. fluorescens, and the homologous His102, Ser332, and Asn333 in human kynureninase. Asn333 can form a hydrogen bond to the 3-OH of 3-hydroxykynurenine in the human enzyme. Halogenation of kynurenine at C-5 increases activity with both enzymes, but halogenation at C-3 only increases activity for human kynureninase. The effect of halogenation at C-5 may be due to hydrophobic or van der Waals effects, and the effect of halogenation at C-3 for the human enzyme may be due to halogen bonding.
Topics: Amino Acid Sequence; Animals; Humans; Hydrolases; Molecular Sequence Data; Pseudomonas fluorescens; Pyridoxal Phosphate; Sequence Alignment; Substrate Specificity
PubMed: 24200862
DOI: 10.1016/j.abb.2013.10.020 -
Journal of Dairy Science Jun 2001Pseudomonas fluorescens isolates (n = 55) isolated from farm bulk tank milk (n = 55) from dairy herds in eastern South Dakota and western Minnesota were examined for...
Pseudomonas fluorescens isolates (n = 55) isolated from farm bulk tank milk (n = 55) from dairy herds in eastern South Dakota and western Minnesota were examined for phenotypic (biotype, proteolytic, and lipolytic profiles) and genotypic (plasmid profiles and 16S-23S PCR ribotypes) characteristics. The observed phenotypic and genotypic characteristics were used to conduct phylogenetic analysis. Pseudomonas fluorescens belonged to 28 API 20 NE biotypes and 14 proteolytic and lipolytic profiles. It was observed that 80, 91, and 58% of the isolates were proteolytic at 7, 22, and 32 degrees C, respectively. Only 7, 44, and 7% of the isolates were lipolytic at the same three temperatures. Pseudomonas fluorescens was more likely to produce proteinases at 7 and 22 degrees C and lipases at 22 degrees C. Only 9 of 55 isolates of P. fluorescens harbored plasmids. This small percentage of plasmid-bearing isolates provided insufficient data for inferences related to the distribution of plasmid-bearing clonal types. Based on 16S-23S PCR ribotyping, P. fluorescens belonged to 14 subtypes. The 16S-23S PCR ribotyping technique allowed differentiation between strains; however, it did not concur with the biotypes and proteolytic and lipolytic profiles. Use of biotypes in conjunction with proteolytic and lipolytic profiles might have practical value for conducting trace-back studies related to P. fluorescens. Based on phylogenetic analysis, it was inferred that for the given geographical area and time period, P. fluorescens isolated from farm bulk tank milk consists of a large heterogeneous group of organisms.
Topics: Animals; DNA, Ribosomal; Genotype; Lipolysis; Milk; Milk Proteins; Molecular Weight; Phenotype; Phylogeny; Pseudomonas fluorescens; RNA, Ribosomal, 16S; RNA, Ribosomal, 23S; Temperature
PubMed: 11417701
DOI: 10.3168/jds.S0022-0302(01)70174-9 -
Journal of Biotechnology Dec 2011Vanillin 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...
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.
Topics: Bacterial Proteins; Benzaldehydes; Biomass; Cloning, Molecular; Coumaric Acids; Fermentation; Hydrogen-Ion Concentration; Metabolic Engineering; Mutagenesis; Pseudomonas fluorescens
PubMed: 21875627
DOI: 10.1016/j.jbiotec.2011.08.014 -
International Journal of Food... Mar 2018Pseudomonas fluorescens, an important food spoiling bacteria, uses quorum sensing to control biofilm formation and motility. To date, only a few compounds targeting the...
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.
Topics: Acrolein; Acyl-Butyrolactones; Anti-Bacterial Agents; Biofilms; Molecular Docking Simulation; Pseudomonas fluorescens; Quorum Sensing; Repressor Proteins; Trans-Activators; Virulence Factors
PubMed: 29421365
DOI: 10.1016/j.ijfoodmicro.2018.01.023 -
Cell Biology and Toxicology Feb 2015The molecular response of Pseudomonas fluorescens cells exposed to a mixture of heavy metals remains largely unknown. Here, we studied the temporal changes in the early...
The molecular response of Pseudomonas fluorescens cells exposed to a mixture of heavy metals remains largely unknown. Here, we studied the temporal changes in the early gene expression of P. fluorescens cells exposed to three doses of a polymetallic solution over two exposure times, through the application of a customized cDNA microarray. At the lowest metal dose (MD/4), we observed a repression of the Hsp70 chaperone system, MATE and MFS transporters, TonB membrane transporter and histidine kinases, together with an overexpression of metal transport (ChaC, CopC), chemotaxis and glutamine synthetase genes. At the intermediate metal dose (MD), several amino acid transporters, a response regulator (CheY), a TonB-dependent receptor and the mutT DNA repair gene were repressed; by contrast, an overexpression of genes associated with the antioxidative stress system and the transport of chelates and sulfur was observed. Finally, at the highest metal dose (4MD), a repression of genes encoding metal ion transporters, drug resistance and alginate biosynthesis was found, together with an overexpression of genes encoding antioxidative proteins, membrane transporters, ribosomal proteins, chaperones and proteases. It was concluded that P. fluorescens cells showed, over exposure time, a highly complex molecular response when exposed to a polymetallic solution, involving mechanisms related with chemotaxis, signal transmission, membrane transport, cellular redox state, and the regulation of transcription and ribosomal activity.
Topics: Bacterial Proteins; Cadmium Compounds; Chemotaxis; Copper; Environmental Pollutants; Gene Expression; Gene Expression Regulation, Bacterial; Genes, Bacterial; Lead; Nickel; Nitrates; Pseudomonas fluorescens; Silver Nitrate; Zinc Compounds
PubMed: 25754557
DOI: 10.1007/s10565-015-9294-9 -
Biotechnology Progress 2005Antifungal activity against Rhizoctonia solani was achieved in vivo through the application of Pseudomonas fluorescens strain 134 encapsulated in sodium alginate beads...
Antifungal activity against Rhizoctonia solani was achieved in vivo through the application of Pseudomonas fluorescens strain 134 encapsulated in sodium alginate beads of different sizes (0.5, 1, and 2 mm). The activity was compared to that obtainable with chemical treatments and bead-derived liquid formulations. The latter was obtained by dissolving alginate beads of 1 and 0.5 mm in 1% Na-citrate solution before application, without any significant (P < 0.05) reduction of bacterial numbers during the dissolution process. The dry bead formulations were applied next to the seeds in plant inoculation experiments, resulting in a reduction of disease symptoms, which were markedly reduced when the liquid formulation was applied. Moreover, the rate of disease symptoms related to liquid formulations from both 1 and 0.5 mm beads was comparable (near to 10%) to that of chemical treatment. Pseudomonas fluorescens strain 134 delivered as both dry and liquid formulations was able to colonize cotton root at a population density of about 10(8) CFU/g fresh root, 15 days after sowing.
Topics: Alginates; Antifungal Agents; Biotechnology; Cells, Cultured; Cells, Immobilized; Citrates; Glucuronic Acid; Gossypium; Hexuronic Acids; Models, Biological; Plant Roots; Pseudomonas fluorescens; Rhizoctonia; Sodium Citrate
PubMed: 15903270
DOI: 10.1021/bp040030w -
Antibiotiki Feb 1981
Review
Topics: Aminoglycosides; Anti-Bacterial Agents; Chemical Phenomena; Chemistry; Heterocyclic Compounds; Peptides; Phenazines; Pseudomonas fluorescens; Pyrroles; Structure-Activity Relationship
PubMed: 6782949
DOI: No ID Found