Zeitschriftenartikel: „Pseudomonas putida mt2“

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Briganti, Fabrizio, Stefano Mangani, Hans Nolting und Andrea Scozzafava. „EXAFS studies on the catechol 2,3 dioxygenase from Pseudomonas putida MT2“. Journal of Inorganic Biochemistry 51, Nr. 1-2 (Juli 1993): 182. http://dx.doi.org/10.1016/0162-0134(93)85218-w.

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Bertini, Ivano, Fabrizio Briganti, Stefano Mangani, Hans F. Nolting und Andrea Scozzafava. „X-ray Absorption Studies on Catechol 2,3-Dioxygenase from Pseudomonas putida MT2“. Biochemistry 33, Nr. 35 (September 1994): 10777–84. http://dx.doi.org/10.1021/bi00201a027.

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Tran, Phuong, John Lan und Ruey-Shin Juang. „Biodecolorization of Methyl Orange in Paint-PVA Biofilm System by Pseudomonas putida mt2“. Current Biochemical Engineering 1, Nr. 1 (27.10.2013): 60–64. http://dx.doi.org/10.2174/22127119113019990003.

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Shamim, Saba, Abdul Rehman und Mahmood Hussain Qazi. „Cadmium-Resistance Mechanism in the Bacteria Cupriavidus metallidurans CH34 and Pseudomonas putida mt2“. Archives of Environmental Contamination and Toxicology 67, Nr. 2 (05.03.2014): 149–57. http://dx.doi.org/10.1007/s00244-014-0009-7.

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Briganti, Fabrizio, und Andrea Scozzafava. „Inhibitor interactions with the active site of catechol 2,3 dioxygenase from pseudomonas putida MT2“. Journal of Inorganic Biochemistry 51, Nr. 1-2 (Juli 1993): 74. http://dx.doi.org/10.1016/0162-0134(93)85110-t.

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Thao, Tran Phuong, Hsiang-Chien Kao, Ruey-Shin Juang und John Chi-Wei Lan. „Kinetic characteristics of biodegradation of methyl orange by Pseudomonas putida mt2 in suspended and immobilized cell systems“. Journal of the Taiwan Institute of Chemical Engineers 44, Nr. 5 (September 2013): 780–85. http://dx.doi.org/10.1016/j.jtice.2013.01.015.

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Volkland, H. P., H. Harms, O. Wanner und A. J. B. Zehnder. „Corrosion protection by anaerobiosis“. Water Science and Technology 44, Nr. 8 (01.10.2001): 103–6. http://dx.doi.org/10.2166/wst.2001.0475.

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Biofilm-forming bacteria can protect mild (unalloyed) steel from corrosion. Mild steel coupons incubated with Rhodoccocus sp. strain C125 and Pseudomonas putida mt2 in an aerobic phosphate-buffered medium containing benzoate as carbon and energy source, underwent a surface reaction leading to the formation of a corrosion-inhibiting vivianite layer [Fe3(PO4)2]. Electrochemical potential (E) measurements allowed us to follow the buildup of the vivianite cover. The presence of sufficient metabolically active bacteria at the steel surface resulted in an E decrease to -510 mV, the potential of free iron, and a continuous release of ferrous iron. Part of the dissolved iron precipitated as vivianite in a compact layer of two to three microns in thickness. This layer prevented corrosion of mild steel for over two weeks, even in a highly corrosive medium. A concentration of 20 mM phosphate in the medium was found to be a prerequisite for the formation of the vivianite layer.

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Shamim, Saba, Abdul Rehman und Mahmood Hussain Qazi. „Swimming, Swarming, Twitching, and Chemotactic Responses of Cupriavidus metallidurans CH34 and Pseudomonas putida mt2 in the Presence of Cadmium“. Archives of Environmental Contamination and Toxicology 66, Nr. 3 (05.12.2013): 407–14. http://dx.doi.org/10.1007/s00244-013-9966-5.

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Dinkla, Inez J. T., Esther M. Gabor und Dick B. Janssen. „Effects of Iron Limitation on the Degradation of Toluene by Pseudomonas Strains Carrying the TOL (pWWO) Plasmid“. Applied and Environmental Microbiology 67, Nr. 8 (01.08.2001): 3406–12. http://dx.doi.org/10.1128/aem.67.8.3406-3412.2001.

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ABSTRACT Most aerobic biodegradation pathways for hydrocarbons involve iron-containing oxygenases. In iron-limited environments, such as the rhizosphere, this may influence the rate of degradation of hydrocarbon pollutants. We investigated the effects of iron limitation on the degradation of toluene by Pseudomonas putida mt2 and the transconjugant rhizosphere bacterium P. putidaWCS358(pWWO), both of which contain the pWWO (TOL) plasmid that harbors the genes for toluene degradation. The results of continuous-culture experiments showed that the activity of the upper-pathway toluene monooxygenase decreased but that the activity of benzyl alcohol dehydrogenase was not affected under iron-limited conditions. In contrast, the activities of three meta-pathway (lower-pathway) enzymes were all found to be reduced when iron concentrations were decreased. Additional experiments in which citrate was used as a growth substrate and the pathways were induced with the gratuitous inducer o-xylene showed that expression of the TOL genes increased the iron requirement in both strains. Growth yields were reduced and substrate affinities decreased under iron-limited conditions, suggesting that iron availability can be an important parameter in the oxidative breakdown of hydrocarbons.

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Volkland, Hans-Peter, Hauke Harms, Beat Müller, Gernot Repphun, Oskar Wanner und Alexander J. B. Zehnder. „Bacterial Phosphating of Mild (Unalloyed) Steel“. Applied and Environmental Microbiology 66, Nr. 10 (01.10.2000): 4389–95. http://dx.doi.org/10.1128/aem.66.10.4389-4395.2000.

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ABSTRACT Mild (unalloyed) steel electrodes were incubated in phosphate-buffered cultures of aerobic, biofilm-formingRhodococcus sp. strain C125 and Pseudomonas putida mt2. A resulting surface reaction leading to the formation of a corrosion-inhibiting vivianite layer was accompanied by a characteristic electrochemical potential (E) curve. First, E increased slightly due to the interaction of phosphate with the iron oxides covering the steel surface. Subsequently, E decreased rapidly and after 1 day reached −510 mV, the potential of free iron, indicating the removal of the iron oxides. At this point, only scattered patches of bacteria covered the surface. A surface reaction, in which iron was released and vivianite precipitated, started. E remained at −510 mV for about 2 days, during which the vivianite layer grew steadily. Thereafter, E increased markedly to the initial value, and the release of iron stopped. Changes in E and formation of vivianite were results of bacterial activity, with oxygen consumption by the biofilm being the driving force. These findings indicate that biofilms may protect steel surfaces and might be used as an alternative method to combat corrosion.

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Hugo, N., C. Meyer, J. Armengaud, J. Gaillard, K. N. Timmis und Y. Jouanneau. „Characterization of Three XylT-Like [2Fe-2S] Ferredoxins Associated with Catabolism of Cresols or Naphthalene: Evidence for Their Involvement in Catechol Dioxygenase Reactivation“. Journal of Bacteriology 182, Nr. 19 (01.10.2000): 5580–85. http://dx.doi.org/10.1128/jb.182.19.5580-5585.2000.

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ABSTRACT The xylT gene product, a component of the xylene catabolic pathway of Pseudomonas putida mt2, has been recently characterized as a novel [2Fe-2S] ferredoxin which specifically reactivates oxygen-inactivated catechol 2,3-dioxygenase (XylE). In this study, three XylT-like proteins potentially involved in the catabolism of naphthalene (NahT) or cresols (PhhQ and DmpQ) have been overexpressed in Escherichia coli, purified, and compared with respect to their biochemical properties and interaction with XylE. The three XylT analogues show general spectroscopic characteristics common to plant-type [2Fe-2S] ferredoxins as well as distinctive features that appear to be typical for the XylT subgroup of these proteins. The midpoint redox potentials of the PhhQ and DmpQ proteins were −286 mV and −323 mV, respectively. Interestingly, all purified XylT-like proteins promoted in vitro reactivation of XylE almost as efficiently as XylT. The interaction of XylE with XylT and its analogues was studied by cross-linking experiments using the 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide. A polypeptide band with an M r of 46,000, which corresponded to the cross-linked product between one XylE subunit and one molecule of ferredoxin, was obtained in all cases. The formation of the complex was affected by ionic strength, indicating that electrostatic forces are involved in the dioxygenase-ferredoxin interaction. In complementation experiments, plasmids expressing xylT or its analogues were introduced into an XylT-null mutant of P. putida which is unable to grow on p-methylbenzoate. All transconjugants regained the wild-type phenotype, indicating that all analogues can substitute for XylT in the in vivo reactivation of XylE. Our results provide evidence for a subgroup of [2Fe-2S] ferredoxins with distinct biochemical properties whose specific function is to reactivate intrinsically labile extradiol ring cleavage dioxygenases involved in the catabolism of various aromatic hydrocarbons.

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Katsuwon, J., R. Zdor und A. J. Anderson. „Superoxide dismutase activity in root-colonizing pseudomonads“. Canadian Journal of Microbiology 39, Nr. 4 (01.04.1993): 420–29. http://dx.doi.org/10.1139/m93-061.

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Several saprophytic fluorescent pseudomonads that are aggressive root colonizers express similar specific activities of superoxide dismutase during growth in liquid culture. The pseudomonads have the potential to produce hydrogen peroxide sensitive and hydrogen peroxide insensitive isoforms of superoxide dismutase with distinct mobilities in nondenaturing polyacrylamide gel electrophoresis. Synthesis of the hydrogen peroxide insensitive form is enhanced by limited iron availability, by exposure to Mn2+, and to a lesser extent by external sources of superoxide anion. Unlike Pseudomonas aeruginosa, a root-colonizing strain of Pseudomonas putida did not show regulation of isoform pattern by phosphate availability. A plasmid potentially encoding the pseudomonad hydrogen peroxide sensitive form complemented the superoxide dismutase deficiency in a mutant of Escherichia coli lacking expression of both Fe and Mn genes. Contact between the plant root and pseudomonad or E. coli cells that lack or express superoxide dismutase did not influence superoxide anion production from root surface enzymes. The pseudomonad and the superoxide dismutase deficient and producing E. coli strains survived exposure to the root equally well. Only the hydrogen peroxide sensitive isoform of superoxide dismutase was detected in P. putida cells associated with bean root surfaces.Key words: pseudomonads, activated oxygen, root surface colonization.

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Eisenmann, Heinrich, Hauke Harms, Rainer Meckenstock, Elisabeth I. Meyer und Alexander J. B. Zehnder. „Grazing of a Tetrahymena sp. on Adhered Bacteria in Percolated Columns Monitored by In Situ Hybridization with Fluorescent Oligonucleotide Probes“. Applied and Environmental Microbiology 64, Nr. 4 (01.04.1998): 1264–69. http://dx.doi.org/10.1128/aem.64.4.1264-1269.1998.

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ABSTRACT Predation of attached Pseudomonas putida mt2 by the small ciliate Tetrahymena sp. was investigated with a percolated column system. Grazing rates were examined under static and dynamic conditions and were compared to grazing rates in batch systems containing suspended prey. The prey densities were 2 × 108 bacteria per ml of pore space and 2 × 108 bacteria per ml of suspension, respectively. Postingestion in situ hybridization of bacteria with fluorescent oligonucleotide probes was used to quantify ingestion. During 30 min, a grazing rate of 1,382 ± 1,029 bacteria individual−1h−1 was obtained with suspended prey; this was twice the grazing rate observed with attached bacteria under static conditions. Continuous percolation at a flow rate of 73 cm h−1 further decreased the grazing rate to about 25% of the grazing rate observed with suspended prey. A considerable proportion of the protozoans fed on neither suspended bacteria nor attached bacteria. The transport of ciliates through the columns was monitored at the same time that predation was monitored. Less than 20% of the protozoans passed through the columns without being retained. Most of these organisms ingested no bacteria, whereas the retained protozoans grazed more efficiently. Retardation of ciliate transport was greater in columns containing attached bacteria than in bacterium-free columns. We propose that the correlation between grazing activity and retardation of transport is a consequence of the interaction between active predators and attached bacteria.

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YORIFUJI, Takamitsu, und Setsuo FURUYOSHI. „Mn2+-dependent amidinoaspartase in Pseudomonas putida.“ Agricultural and Biological Chemistry 50, Nr. 5 (1986): 1327–28. http://dx.doi.org/10.1271/bbb1961.50.1327.

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Swift, R. J., S. F. Carter, D. A. Widdowson, J. R. Mason und D. J. Leak. „Expression of benzene dioxygenase from Pseudomonas putida ML2 in cis -1,2-cyclohexanediol-degrading pseudomonads“. Applied Microbiology and Biotechnology 55, Nr. 6 (01.06.2001): 721–26. http://dx.doi.org/10.1007/s002530100593.

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Tan, Hai-Meng, und Karen P. Y. Fong. „Molecular analysis of the plasmid-borne bed gene cluster from Pseudomonas putida ML2 and cloning of the cis-benzene dihydrodiol dehydrogenase gene“. Canadian Journal of Microbiology 39, Nr. 4 (01.04.1993): 357–62. http://dx.doi.org/10.1139/m93-052.

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Pseudomonas putida ML2 contains a large catabolic plasmid, pHMT112, carrying genes that encode the dioxygenase and dehydrogenase involved in the catabolism of benzene via the ortho or β-ketoadipate pathway. pHMT112 was derived from a larger and less stable plasmid in P. putida ML2 following growth on succinate as carbon and energy source but was, however, stably maintained in P. putida even in the absence of selection for growth on benzene. Cleavage sites for the restriction endonucleases DraI, XbaI, and BamHI were mapped on the plasmid. A region of the plasmid, downstream of the benzene dioxygenase genes (bedC1C2BA), was found to encode the cis-benzene dihydrodiol dehydrogenase gene (bedD). Recombinant Escherichia coli containing bedC1C2BAD genes was found to express benzene dioxygenase and dehydrogenase activity, indicated by the production of catechol when incubated in the presence of benzene. Hybridization using benzene dioxygenase genes as probes was used to construct a restriction map of the 35.5-kb XhoI–DraI fragment on which the bed operon was located.Key words: Pseudomonas putida, catabolic plasmid, dioxygenase, dehydrogenase.

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de Vrind, J. P. M., G. J. Brouwers, P. L. A. M. Corstjens, J. den Dulk und E. W. de Vrind-de Jong. „The Cytochrome c Maturation Operon Is Involved in Manganese Oxidation in Pseudomonas putidaGB-1“. Applied and Environmental Microbiology 64, Nr. 10 (01.10.1998): 3556–62. http://dx.doi.org/10.1128/aem.64.10.3556-3562.1998.

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ABSTRACT A Pseudomonas putida strain, strain GB-1, oxidizes Mn2+ to Mn oxide in the early stationary growth phase. It also secretes a siderophore (identified as pyoverdine) when it is subjected to iron limitation. After transposon (Tn5) mutagenesis several classes of mutants with differences in Mn2+ oxidation and/or secretion of the Mn2+-oxidizing activity were identified. Preliminary analysis of the Tn5 insertion site in one of the nonoxidizing mutants suggested that a multicopper oxidase-related enzyme is involved in Mn2+ oxidation. The insertion site in another mutant was preliminarily identified as a gene involved in the general protein secretion pathway. Two mutants defective in Mn2+-oxidizing activity also secreted porphyrins into the medium and appeared to be derepressed for pyoverdine production. These strains were chosen for detailed analysis. Both mutants were shown to contain Tn5 insertions in the ccmF gene, which is part of the cytochrome c maturation operon. They were cytochrome oxidase negative and did not contain c-type cytochromes. Complementation with part of the ccm operon isolated from the wild type restored the phenotype of the parent strain. These results indicate that a functional ccm operon is required for Mn2+ oxidation in P. putidaGB-1. A possible relationship between porphyrin secretion resulting from the ccm mutation and stimulation of pyoverdine production is discussed.

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Jankiewicz, Urszula, Maria Swiontek-Brzezinska, Ewa Beata Górska und Paweł Kowalczyk. „Characterization and Mass Spectrometry Analysis of Aminopeptidase N from Pseudomononas putida Lup.“ Polish Journal of Microbiology 62, Nr. 4 (2013): 337–43. http://dx.doi.org/10.33073/pjm-2013-046.

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An intracellular aminopeptidase N synthesized by Pseudomonas putida Lup was purified and characterized. The approx. 150-fold purified enzyme showed highest activity against A-beta-naphthylamide at pH 7.5 and at temperature 40 degrees C and was 100% thermostable for 240 min at 40 degrees C. P putida lup aminopeptidase N is a monomer with molecular mass approx. 99 kDa determined by SDS-PAGE and gel permeation chromatography. The enzyme has broad substrate specificity, but is the most active against protein substrates with N-terminal alanine and arginine. The activity of P. putida Lup aminopeptidase N is strongly inhibited in the presence of specific metallopeptidase inhibitors and is partly recovered in the presence of Zn2+ and Co2+ ions. Co2+, Mg2+ and Ca2+ ions increased the activity of the enzyme. Moreover, the enzyme was inhibited by inhibitors of cysteine enzymes. Analysis of fragments of the amino acid sequence of the purified enzyme demonstrated high similarity to PepN of Pseudomonas putida GB-1.

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Zamanian, M., und J. R. Mason. „Benzene dioxygenase in Pseudomonas putida. Subunit composition and immuno-cross-reactivity with other aromatic dioxygenases“. Biochemical Journal 244, Nr. 3 (15.06.1987): 611–16. http://dx.doi.org/10.1042/bj2440611.

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The terminal oxygenase component of benzene dioxygenase from Pseudomonas putida strain ML2 was shown to contain two subunits, of Mr 54,500 and 23,500, by SDS/polyacrylamide-gel electrophoresis. The native Mr of the terminal oxygenase was estimated to be 168,000 +/- 4000. Polyclonal antibodies raised against each of the subunits cross-reacted with two polypeptides in cell-free extracts from toluene-grown Pseudomonas putida strain N.C.I.B. 11767. The Mr values of these polypeptides were similar to those reported for the subunits from the terminal dioxygenase component of toluene dioxygenase. These polypeptides were present only when this strain was grown on toluene. No cross-reactivity was observed with subunits of the naphthalene dioxygenase or benzoate dioxygenase systems.

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Savard, Pierre, Hugues Charest, Michel Sylvestre, François Shareck, Jeffrey D. Scholten und Debra Dunaway Mariano. „Expression of the 4-chlorobenzoate dehalogenase genes from Pseudomonas sp. CBS3 in Escherichia coli and identification of the gene translation products“. Canadian Journal of Microbiology 38, Nr. 10 (01.10.1992): 1074–83. http://dx.doi.org/10.1139/m92-176.

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The genes encoding the 4-chlorobenzoate dehalogenase of Pseudomonas sp. strain CBS3 were, in an earlier study, cloned in Escherichia coli DH1 with the cosmid vector pPSA843 and then mobilized to the 4-chlorobenzoate dehalogenase minus strain Pseudomonas putida KT2440. In this paper we report on the expression of 4-chlorobenzoate dehalogenase in these clones and on the polypeptide composition of the active enzyme. The dehalogenase activity in whole cells suspended in 3.2 mM 4-chlorobenzoate (30 °C) was determined to be approximately 27 units (micromoles 4-hydroxybenzoate produced per minute) per 100 g of E. coli - pPSA843 cells and approximately 28 units per 100 g of P. putida-pPSA843 cells. Dehalogenase activity in fresh cellular extracts (pH 7.4, 30 °C) prepared from the is. E. coli and P. putida clones was unstable and at least 20-fold lower than that observed with the whole cells. The polypeptide components of the dehalogenase were identified by selective expression of the cloned dehalogenase genes and analysis of the gene translation products. Analysis of dehalogenase activity in Ω insertion mutants and deletion mutants circumscribed the dehalogenase genes to a 4.8-kilobase (4.8 kb) stretch of the 9.5-kb DNA fragment. Selective expression of the dehalogenase genes from a cloned 4.8-kb DNA fragment in a maxicell system revealed a 30-kDa polypeptide as one of the components of the dehalogenase system. Selective expression of the dehalogenase genes using the T7 polymerase promoter system revealed the 30-kDa polypeptide and 57- and 16-kDa polypeptide products. Determination of which of the three polypeptides were translated in deletion mutants provided the relative positions of the encoding genes on a single DNA strand and the direction in which they are transcribed. Key words: peptide expression, bacteria, dehalogenation, gene product analysis.

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Katsuwon, J., und A. J. Anderson. „Characterization of catalase activities in a root-colonizing isolate of Pseudomonas putida“. Canadian Journal of Microbiology 38, Nr. 10 (01.10.1992): 1026–32. http://dx.doi.org/10.1139/m92-169.

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Pseudomonas putida, a saprophytic root-colonizing bacterium, produces multiple forms of catalase. Catalase A, which increases in specific activity during growth phase and after treatment with H2O2, is located in the cytoplasm and is inhibited by 3-amino-1,2,4-triazole, EDTA, and cyanide, but not by chloroform–methanol treatment. Catalase B, which is induced by external H2O2 or during stationary phase of growth, is membrane associated and is inhibited by chloroform–methanol, EDTA, and cyanide, but not by aminotriazole. Catalase A has a broad pH optimum, from pH 6.0 to 11.0, with two peaks, at pH 8.0 and 11.0. Catalase B is most active at pH 5.0–11.0. Mutant J-1, generated by ethyl methanesulfonate mutagenesis, lacked catalase A activity in extracts of cells harvested throughout lag to early stationary growth phase in liquid medium. Catalase B was produced by J-1 in stationary phase. Exposure of J-1 to H2O2 caused the production of both catalase A and catalase B. Mutant J-1 was more susceptible to cell death than the wild type upon direct exposure to 2.5 mM H2O2 but survived this treatment after exposure to lower (0.3 mM), nonlethal doses of H2O2. The ability to adapt to H2O2 may be related to the behaviour of J-1 on roots where active oxygen species are produced by root surface enzymes. J-1 colonized root surfaces at wild-type levels and produced catalases A and B after exposure to root surfaces for 12 h. Key words: Pseudomonas putida, catalase, root colonization.

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Tan, Hai-Meng, Shuan-Pei Cheong und Thiam-Chye Tan. „An amperometric benzene sensor using whole cell Pseudomonas putida ML2“. Biosensors and Bioelectronics 9, Nr. 1 (1994): 1–8. http://dx.doi.org/10.1016/0956-5663(94)80008-1.

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Louis Mary, L. Christilda, R. Sujatha, A. J. Chozhaa und P. Mohideen Askar Navas. „Influence of Organic Manures (Biofertilizers) on Soil Microbial Population in the Rhizosphere of Mulberry (Morus Indica L.)“. International Journal of Applied Sciences and Biotechnology 3, Nr. 1 (25.03.2015): 61–66. http://dx.doi.org/10.3126/ijasbt.v3i1.12137.

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The effect of different kinds of organic manures on soil microbial population and mulberry production was assessed. A field experiment wascarried out at Periyar EVR College, Tamil Nadu, India in basic soil to study the influence of organic manures on soil bacterial population andmulberry production. The 4 groups of mulberry plants of MR2 variety were biofertilized with FYM, Azospirillum, Phosphobacteria andVermicompost respectively. The biofertilizers lodged bacteria on the rhizosphere of mulberry plants. When the root microorganism areanalyzed Farm yard manure biofertilized mulberry plant root tips had Gluconacobacter diazotrophicus, Bacillus pumilus, Pseudomonas putida,Bacillus coagulans, Bacillus sonorensis, Azotobacter chrococcum; Azospirillum biofertilized mulberry plants root tips had Bacillus coaculans,Azotobactor chrococcum, Azotobactor vinelandii, Bacillus subtilis and Azospirillum brasilense. Phosphobacteria biofertilized mulberry plantroot tips had Pseudomonas putida, Bacillus stearothermophilus, Brevibacillus borslelansis and Streptomycies thermonitrificans andvermicompost biofertilized mulberry plant root tips had lodged bacterias like Bacillus megaterium, Bacillus subtilis, Gluconacobacterdiazotrophicus, Pseudomonas putida, Azotobacter chrococcum, Azotobacter vinelandi, Bacillus stearothermophilus, Brevibacillus borslelansisand Bacillus sonorensis. Microbiology work reveals luxuriant growth of bacteria in all the biofertizer treated rhizosphere in the order FYM <Azospirillum < Phosphobacteria < Vermicompost. Increased availability of NPK and other micronutrients were noticed in T4 treated plantscompared to other treatments.DOI: http://dx.doi.org/10.3126/ijasbt.v3i1.12137 Int J Appl Sci Biotechnol, Vol. 3(1): 61-66

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Bonilla, M., C. Olivaro, M. Corona, A. Vazquez und M. Soubes. „Production and characterization of a new bioemulsifier from Pseudomonas putida ML2“. Journal of Applied Microbiology 98, Nr. 2 (Februar 2005): 456–63. http://dx.doi.org/10.1111/j.1365-2672.2004.02480.x.

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Brouwers, Geert-Jan, Johannes P. M. de Vrind, Paul L. A. M. Corstjens, Pierre Cornelis, Christine Baysse und Elisabeth W. de Vrind-de Jong. „cumA, a Gene Encoding a Multicopper Oxidase, Is Involved in Mn2+ Oxidation in Pseudomonas putida GB-1“. Applied and Environmental Microbiology 65, Nr. 4 (01.04.1999): 1762–68. http://dx.doi.org/10.1128/aem.65.4.1762-1768.1999.

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ABSTRACT Pseudomonas putida GB-1-002 catalyzes the oxidation of Mn2+. Nucleotide sequence analysis of the transposon insertion site of a nonoxidizing mutant revealed a gene (designatedcumA) encoding a protein homologous to multicopper oxidases. Addition of Cu2+ increased the Mn2+-oxidizing activity of the P. putidawild type by a factor of approximately 5. The growth rates of the wild type and the mutant were not affected by added Cu2+. A second open reading frame (designatedcumB) is located downstream from cumA. BothcumA and cumB probably are part of a single operon. The translation product of cumB was homologous (level of identity, 45%) to that of orf74 ofBradyrhizobium japonicum. A mutation in orf74resulted in an extended lag phase and lower cell densities. Similar growth-related observations were made for the cumAmutant, suggesting that the cumA mutation may have a polar effect on cumB. This was confirmed by site-specific gene replacement in cumB. The cumB mutation did not affect the Mn2+-oxidizing ability of the organism but resulted in decreased growth. In summary, our data indicate that the multicopper oxidase CumA is involved in the oxidation of Mn2+ and that CumB is required for optimal growth of P. putida GB-1-002.

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Kosanke, J. W., R. M. Osburn, G. I. Shuppe und R. S. Smith. „Slow rehydration improves the recovery of dried bacterial populations“. Canadian Journal of Microbiology 38, Nr. 6 (01.06.1992): 520–25. http://dx.doi.org/10.1139/m92-086.

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Slow rehydration of bacteria from dried inoculant formulations provided higher viable counts than did rapid rehydration. Estimates were higher when clay and peat powder formulations of Rhizobium meliloti, Rhizobium leguminosarum biovar trifolii, and Pseudomonas putida, with water activities between 0.280 and 0.650, were slowly rehydrated to water activities of approximately 0.992 before continuing the dilution plating sequence. Rhizobium meliloti populations averaged 6.8 × 108 cfu/g and 1328 cfu/alfalfa seed greater when slowly rehydrated from bulk powder and preinoculated seeds, respectively. Bulk powder samples were slowly rehydrated to 0.992 water activity by the gradual addition of diluent, followed by a 10-min period for moisture equilibration. Preinoculated seed samples were placed in an environmental chamber at 24 °C with relative humidity greater than 80% for 1 h to allow moisture absorption. "Upshock," osmotic cellular stresses that occur during rehydration, was reduced when dried microbial formulations were slowly rehydrated and equilibrated before becoming fully hydrated in the dilution plating sequence. These procedures may also be applicable when estimating total viable bacterial populations from dried soil or other dry formulations. Key words: rehydration procedure, microbial rehydration, desiccation, Rhizobium, Pseudomonas.

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Elaasser, M., und R. El Kassas. „Detoxification of aflatoxin B1 by certain bacterial species isolated from Egyptian soil“. World Mycotoxin Journal 4, Nr. 2 (01.01.2011): 169–76. http://dx.doi.org/10.3920/wmj2010.1262.

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Aflatoxin contamination of food and grain poses a serious economic and health problem worldwide. Aflatoxin B1 (AFB1) is extremely mutagenic, toxic and a potent carcinogen to both humans and livestock. A safe, effective and environmentally sound detoxification method is needed for controlling this toxin. In this study, 21 soil samples were screened from various sources with vast microbial populations using a coumarin containing medium. Eleven bacterial isolates showing AFB1 reduction activity in a liquid culture medium were selected from the screening experiments. Isolate 12-3 and 12-5, obtained from soil samples of Kafr-Zaiat Pesticide company drainage and identified to be Pseudomonas putida and Escherichia coli, reduced AFB1 by 69.3% and 58.8%, respectively, after incubation in the liquid medium at 37 °C for 72 h. The culture supernatant of these isolates was able to reduce AFB1 effectively by 76.2% and 62.5%, respectively, whereas the viable cells and cell extracts were far less effective. Factors influencing AFB1 detoxification by the culture supernatant were investigated. The highest detoxification activity for P. putida and E. coli was 83.3% and 63.8%, respectively, at pH 8 and 30 °C for 72 h. The detoxification activity was reduced at 10, 20 and 45 °C. The Mg2+, Mn2+, Se and Cu2+ ions were activators for AFB1 detoxification. However, Zn2+ ion was a strong inhibitor. Treatments with proteinase K, proteinase K plus SDS and heating significantly reduced or eradicated the detoxification activity of the culture supernatant. In conclusion, the detoxification of AFB1 by P. putida 12-3 was enzymatic and the enzymes responsible for the detoxification of AFB1 are constitutively extracellular produced. Also, the AFB1 detoxification by E. coli was conducted by enzymes as well as by cell wall binding mechanism. Both bacteria could have great potential in industrial applications.

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Majolagbe, Olusola N., Elijah A. Adebayo, Abiodun Ayandele und Louis Ezediuno. „Metalotolerance Capacity of Autochthonous Bacteria Isolated From Industrial Waste Effluent“. Annals of Science and Technology 2, Nr. 1 (01.12.2017): 13–17. http://dx.doi.org/10.2478/ast-2018-0003.

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AbstractMicrobes play significant roles in remediation of heavy metal polluted industrial effluent using the mechanisms of biosorption and bioaccumulation. In the present study, six heavy metal resistant autochthonous bacteria species namely Bacillus cereus, B. megaterium, B. subtilis, Flavobacterium aquatile, Pseudomonas flourescens and Pseudomonas putida were isolated from effluent samples collected from Paper-mill industry (PMI), Paints and Chemicals Industry (PCI), and Steel-rolling Industry (SRI). The isolates were studied for their heavy metal tolerant capacities at different aqueous salt concentrations. Elemental analysis of the industrial effluent samples collected indicated the presence of heavy metals such as Copper (Cu2+), Manganese (Mn2+), Iron (Fe2+) and Lead (Pb2+) at varying concentrations in μg/ml. Generally, there were variations in the minimum inhibitory concentrations (MIC) of the heavy metal salt to each of the bacteria understudy. The MIC value of each of the bacterial isolates to aqueous solution of Cu2SO4 showed that B. megaterium, B. subtilis, Pseudomonas flourescens and Pseudomonas putida had the same MIC value of 20 ± 1.5 μg/mL while Bacillus cereus and Flavobacterium aquatile had MIC values of 13 ± 1.3 μg/mL and 25 ± 2.1 μg/mL respectively. This variation was also noticeable in aqueous salts of Mn2SO4, Fe2SO4 and Pb2SO4.The bacteria isolates showed sensitivity to heavy metals with increasing zone of inhibition as concentration increased with each isolate showing varying degree of metalotolerance. The effectiveness of the autochthonous bacteria as a means to bio-augment the remediation of heavy metal polluted industrial effluent was further proven and recommended.

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Tan, H. M., C. L. Joannou, C. E. Cooper, C. S. Butler, R. Cammack und J. R. Mason. „The effect of ferredoxin(BED) overexpression on benzene dioxygenase activity in Pseudomonas putida ML2.“ Journal of Bacteriology 176, Nr. 9 (1994): 2507–12. http://dx.doi.org/10.1128/jb.176.9.2507-2512.1994.

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Martín, M. L., und A. Garrido-Pertierra. „Isomerase and Decarboxylase Activities in the 4-Hydroxyphenylacetate Catabolic Pathway of Pseudomonas putida“. Zeitschrift für Naturforschung C 40, Nr. 7-8 (01.07.1985): 503–8. http://dx.doi.org/10.1515/znc-1985-7-808.

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Abstract 5-Carboxymethyl-2-hydroxymuconate isomerase and 5-carboxymethyl-2-oxo-hex-3-ene-1,6-dioate decarboxylase in the 4-hydroxyphenylacetate meta-cleavage pathway have been purified to over 98% homogeneity. The native enzymes, which appear to be monomers, have apparent molecular weights of 37,000. The isomerase shows a pH optimum 8.0 and does not require ions for its catalytic activity; Mg2+ is required for the decarboxylase reaction. Apparent Km values for their respective substrates are 2.8 × 10-4м for the isomerase and 1.4 × 10-4м for the decarboxy lase. The highly purified enzymes were used to study the spectral characteristics of the decarboxy lase substrate.

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Mutharia, Lucy M., und Robert E. W. Hancock. „Characterization of two surface-localized antigenic sites on porin protein F of Pseudomonas aeruginosa“. Canadian Journal of Microbiology 31, Nr. 4 (01.04.1985): 381–86. http://dx.doi.org/10.1139/m85-073.

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A rapid colony immunoblot screening procedure was used to demonstrate the surface localization of porin protein F on bacterial colonies of Pseudomonas aeruginosa. By this method, we demonstrated that protein F was accessible to four different specific monoclonal antibodies in a wide variety of both mucoid and nonmucoid P. aeruginosa strains. Controls were performed to demonstrate that, using this procedure, only surface-exposed epitopes bound monoclonal antibodies and that nonspecific binding of monoclonal antibodies either to cells lacking protein F or to mucoid exopolysaccharide did not occur. Monoclonal antibodies MA4-4, MA2-10, and MA4-10, specific for protein F, also interacted with colonies of Pseudomonas putida and Pseudomonas syringae, whereas the protein F specific monoclonal antibody MA5-8 interacted only with P. aeruginosa strains. Using the above-named monoclonal antibodies, we investigated the antigenic structure of protein F. Monoclonal antibodies MA4-4, MA2-10, and MA4-10 bound to 29–31 kilodalton proteolytic fragments produced after papain or trypsin digestion of purified protein F or of protein F in outer membranes or intact cells. Antibody MA5-8 did not interact with proteolytically digested protein F but did interact with two of the six fragments produced after partial cyanogen bromide cleavage of protein F. Antibodies MA4-4, MA2-10, and MA4-10 did not interact with protein F after reduction of its internal disulphide bonds with 2-mercaptoethanol; in contrast, the reactivity of MA5-8 was unaffected. This data suggests that there are at least two distinct highly conserved surface epitopes on porin protein F.

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Arango Pinedo, Catalina, und Barth F. Smets. „Conjugal TOL Transfer from Pseudomonas putida to Pseudomonas aeruginosa: Effects of Restriction Proficiency, Toxicant Exposure, Cell Density Ratios, and Conjugation Detection Method on Observed Transfer Efficiencies“. Applied and Environmental Microbiology 71, Nr. 1 (Januar 2005): 51–57. http://dx.doi.org/10.1128/aem.71.1.51-57.2005.

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ABSTRACT The effects of restriction proficiency and premating exposure to toxicants on conjugal transfer of the TOL plasmid between Pseudomonas spp. was investigated by examinations of filter matings. A Pseudomonas putida KT2442-derived strain carrying a gfp-tagged variant of the TOL plasmid was used as a donor, and both restriction-deficient (PAO1162N) and -proficient (PAO2002N) Pseudomonas aeruginosa strains were used as recipients. The in situ enumeration of conjugation events allowed us to obtain frequency estimates that were unbiased by transconjugant growth or plasmid retransfer. We observed a strong dependence of the plasmid transfer frequency on the initial donor-to-recipient ratio of surface matings, which invalidated the use of mass action-based plasmid transfer kinetic estimators. Careful control of the initial parental cell densities permitted evaluations of the true effects of restriction proficiency and toxicant exposure on TOL transfer. At standard donor-to-recipient ratios (10−3 for PAO1162N and 2 Ã¯Â¿Â½ 101 for PAO2002N) and total cell densities (105 cells/mm2 for PAO1162N and 106 cells/mm2 for PAO2002N), plasmid transfer frequencies without toxicant exposure were approximately 10−7 (events/mm2)−1 for PAO1162N and 10−11 (events/mm2)−1 for PAO2002N based on in situ observations of conjugation events. The enumeration of transconjugants via selective plating yielded transfer frequencies that were up to 1 order of magnitude lower. Premating exposure to sodium dodecyl sulfate (1 to 10 mM) significantly increased the transfer frequency for the restriction-proficient strain PAO2002N (P < 0.05) but not for the restriction-deficient strain PAO1162N. On the other hand, premating exposure to ethanol, toluene, or phenol had no positive effect on the plasmid transfer frequency. Clearly, restriction proficiency provides a strong barrier to interspecific transfer of the TOL plasmid, and this barrier was only marginally attenuated by recipient exposure to toxicants within the ranges examined.

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Domenech, Carlos Eduardo, Lisandro Horacio Otero, Paola Rita Beassoni und Angela Teresita Lisa. „Phosphorylcholine Phosphatase: A Peculiar Enzyme of Pseudomonas aeruginosa“. Enzyme Research 2011 (11.09.2011): 1–12. http://dx.doi.org/10.4061/2011/561841.

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Pseudomonas aeruginosa synthesizes phosphorylcholine phosphatase (PchP) when grown on choline, betaine, dimethylglycine or carnitine. In the presence of Mg2+ or Zn2+, PchP catalyzes the hydrolysis of p-nitrophenylphosphate (p-NPP) or phosphorylcholine (Pcho). The regulation of pchP gene expression is under the control of GbdR and NtrC; dimethylglycine is likely the metabolite directly involved in the induction of PchP. Therefore, the regulation of choline metabolism and consequently PchP synthesis may reflect an adaptive response of P. aeruginosa to environmental conditions. Bioinformatic and biochemistry studies shown that PchP contains two sites for alkylammonium compounds (AACs): one in the catalytic site near the metal ion-phosphoester pocket, and another in an inhibitory site responsible for the binding of the alkylammonium moiety. Both sites could be close to each other and interact through the residues 42E, 43E and 82YYY84. Zn2+ is better activator than Mg2+ at pH 5.0 and it is more effective at alleviating the inhibition produced by the entry of Pcho or different AACs in the inhibitory site. We postulate that Zn2+ induces at pH 5.0 a conformational change in the active center that is communicated to the inhibitory site, producing a compact or closed structure. However, at pH 7.4, this effect is not observed because to the hydrolysis of the [Zn2+L2−1L20(H2O)2] complex, which causes a change from octahedral to tetrahedral in the metal coordination geometry. This enzyme is also present in P. fluorescens, P. putida, P. syringae, and other organisms. We have recently crystallized PchP and solved its structure.

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Feng, Yongmei, Hoon Eng Khoo und Chit Laa Poh. „Purification and Characterization of Gentisate 1,2-Dioxygenases from Pseudomonas alcaligenes NCIB 9867 and Pseudomonas putida NCIB 9869“. Applied and Environmental Microbiology 65, Nr. 3 (01.03.1999): 946–50. http://dx.doi.org/10.1128/aem.65.3.946-950.1999.

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ABSTRACT Two 3-hydroxybenzoate-inducible gentisate 1,2-dioxygenases were purified to homogeneity from Pseudomonas alcaligenes NCIB 9867 (P25X) and Pseudomonas putida NCIB 9869 (P35X), respectively. The estimated molecular mass of the purified P25X gentisate 1,2-dioxygenase was 154 kDa, with a subunit mass of 39 kDa. Its structure is deduced to be a tetramer. The pI of this enzyme was established to be 4.8 to 5.0. The subunit mass of P35X gentisate 1,2-dioxygenase was 41 kDa, and this enzyme was deduced to exist as a dimer, with a native molecular mass of about 82 kDa. The pI of P35X gentisate 1,2-dioxygenase was around 4.6 to 4.8. Both of the gentisate 1,2-dioxygenases exhibited typical saturation kinetics and had apparent Km s of 92 and 143 μM for gentisate, respectively. Broad substrate specificities were exhibited towards alkyl and halogenated gentisate analogs. Both enzymes had similar kinetic turnover characteristics for gentisate, with k cat/Km values of 44.08 × 104 s−1 M−1 for the P25X enzyme and 39.34 × 104 s−1M−1 for the P35X enzyme. Higherk cat/Km values were expressed by both enzymes against the substituted gentisates. Significant differences were observed between the N-terminal sequences of the first 23 amino acid residues of the P25X and P35X gentisate 1,2-dioxygenases. The P25X gentisate 1,2-dioxygenase was stable between pH 5.0 and 7.5, with the optimal pH around 8.0. The P35X enzyme showed a pH stability range between 7.0 and 9.0, and the optimum pH was also 8.0. The optimal temperature for both P25X and P35X gentisate 1,2-dioxygenases was around 50°C, but the P35X enzyme was more heat stable than that from P25X. Both enzymes were strongly stimulated by 0.1 mM Fe2+ but were completely inhibited by the presence of 5 mM Cu2+. Partial inhibition of both enzymes was also observed with 5 mM Mn2+, Zn2+, and EDTA.

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Mulyasuryani, Ani, und Sasangka Prasetyawan. „Organophosphate Hydrolase in Conductometric Biosensor for the Detection of Organophosphate Pesticides“. Analytical Chemistry Insights 10 (Januar 2015): ACI.S30656. http://dx.doi.org/10.4137/aci.s30656.

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The research has developed an enzyme biosensor for the detection organophosphate pesticide residues. The biosensor consists of a pair of screen-printed carbon electrode (SPCEs). One of electrodes contains immobilized organophosphate hydrolase (OPH) on a chitosan membrane by cross-linking it with glutaraldehyde. The area of the electrodes was optimized to 3, 5, and 7 mm2. The OPH was isolated from Pseudomonas putida, and was purified by the ammonium sulfate precipitation method, with 6444 ppm (A) and 7865 ppm (B). The organophosphate pesticide samples were 0-100 ppb in tris-acetate buffer 0.05 M, pH 8.5. The results showed that the best performance of the biosensor was achieved by the enzyme A with an electrode area of 5 mm2. The sensitivity of the biosensor was between 3 and 32 µS/ppb, and the detection limit for the organophosphate pesticides was 40 ppb (diazinon), 30 ppb (malathion), 20 ppb (chlorpyrifos), and 40 ppm (profenofos).

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Huang, Xuejiao, Yaxin Wang, Jiupai Ni, Deti Xie und Zhenlun Li. „Metal oxide nanoparticles resonate to ammonium removal through influencing Mg2+ absorption by Pseudomonas putida Y-9“. Bioresource Technology 296 (Januar 2020): 122339. http://dx.doi.org/10.1016/j.biortech.2019.122339.

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Allen, Christopher C. R., Claire E. Walker, Narain D. Sharma, Nuala A. Kerley, Derek R. Boyd und Howard Dalton. „Selectivity Studies of the Benzene cis -Dihydrodiol Dehydrogenase Enzyme from Pseudomonas putida ML2 with Vicinal Diol Substrates“. Biocatalysis and Biotransformation 20, Nr. 4 (Januar 2002): 257–64. http://dx.doi.org/10.1080/10242420290029454.

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Mason, Jeremy R. „The induction and repression of benzene and catechol oxidizing capacity of Pseudomonas putida ML2 studied in perturbed chemostat culture“. Archives of Microbiology 162, Nr. 1-2 (Juli 1994): 57–62. http://dx.doi.org/10.1007/bf00264373.

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Mason, Jeremy R. „The induction and repression of benzene and catechol oxidizing capacity of Pseudomonas putida ML2 studied in perturbed chemostat culture“. Archives of Microbiology 162, Nr. 1-2 (01.07.1994): 57–62. http://dx.doi.org/10.1007/s002030050101.

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Unalkat, P., O. Hatzfeld, T. A. Link, H.-M. Tan, R. Cammack und J. R. Mason. „Some properties of the [2Fe-2S] Rieske-type ferredoxin and its mutants from benzene dioxygenase in Pseudomonas putida ML2“. Journal of Inorganic Biochemistry 59, Nr. 2-3 (August 1995): 528. http://dx.doi.org/10.1016/0162-0134(95)97623-x.

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Bruins, Jantinus H., Branislav Petrusevski, Yness M. Slokar, Gerhard H. Wübbels, Koen Huysman, Bart A. Wullings, Koen Joris, Joop C. Kruithof und Maria D. Kennedy. „Identification of the bacterial population in manganese removal filters“. Water Supply 17, Nr. 3 (15.11.2016): 842–50. http://dx.doi.org/10.2166/ws.2016.184.

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The aim of this study was to identify bacteria present in ripened manganese removal filters for drinking water production. The bacterial population was identified with ‘next generation’ DNA sequencing, and specific bacteria were quantified with quantitative polymerase chain reaction (qPCR) and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis. The ‘next generation’ DNA sequencing analysis showed a bacteria population shift from the iron oxidizing species Gallionella spp. in the Fe-filter to manganese and nitrite oxidizing species Pseudomonas spp. and Nitrospira spp., respectively, present in the manganese removal filter. qPCR analysis confirmed the presence of a low concentration of the well-known Mn2+-oxidizing species Ps. putida in the manganese removal filter backwash water. Bacteria of the genus Pseudomonas, isolated from backwash water from a manganese removal filter were cultured and identified with MALDI-TOF MS analysis. Amongst others, P. gessardii, P. grimontii, and P. koreensis were identified. The presence of several manganese oxidizing bacteria species in ripened filter media supports the assumption that a microbial consortium is involved in the oxidation of manganese. Understanding the mechanisms by which manganese coating of filter media commences could endorse the creation of conditions favouring Birnessite formation, and possibly help in reducing typically long ripening periods of manganese removal filters with virgin filter media.

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Macías-Holguín, Cristhian John, Hayron Fabricio Canchignia Martínez, Vicenta Dayana Delgado Basurto, Fernando Patricio Paucar-Nieto, Ketty Vanessa Arellano Ibarra und Angel Virgilio Cedeño Moreira. „Efectos de la co-inoculación de Bioformulados (PGPR´s) sobre el porcentaje de germinación y promover el crecimiento en plántula de papaya (Carica papaya L.)“. Manglar 20, Nr. 2 (05.07.2023): 149–55. http://dx.doi.org/10.57188/manglar.2023.017.

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Dormancy is a blockage to germination and represents an adaptive mechanism that allows papaya seed to delay its emergence. Rhizobacteria improve plant growth in several ways, phytohormone production, nitrogen fixation, phosphate solubilization and increase root morphology. The present investigation was conducted to determine the efficiency of rhizobacteria (PGPR's) Pseudomona protegens (CHA0) and Pseudomona putida (BMR 2-4) inoculated within three bioformulates to be evaluated within the percentage of germination, increase of absorbing hairs using rhizotrons and seedlings under consortia or in combination of phosphorus fertilizers. Under in-vitro conditions, BIOIMPULSE co-inoculation was very effective in increasing germination percentage with an average of 80%. In rhizotrons, a greater increase in absorbing hairs of 5.67 mm and root area of 0.86 mm2 per BIOIMPULSE was exhibited, comparable to the treatment with AIA (25 mg/mL). In seedlings, BIOIMPULSE is highly effective in improving root morphology and height by emendando 5 g/L phosphorus was observed Ø hypocotyl dimensions between (5.12 to 4.62 mm) and functional leaves (9.75 to 11.75). BIOIMPULSE modifies root functioning, improves plant nutrition, and influences vegetative physiology, being versatile over all other bioformulates by increasing the germination percentage, early appearance of root hairs and root growth in the presence of phosphorus fertilizers. This means that they can be useful to reduce the cost of chemical fertilizers.

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Tan, H. M., H. Y. Tang, C. L. Joannou, N. H. Abdel-Wahab und J. R. Mason. „The Pseudomonas putida ML2 plasmid-encoded genes for benzene dioxygenase are unusual in codon usage and low in G + C content“. Gene 130, Nr. 1 (August 1993): 33–39. http://dx.doi.org/10.1016/0378-1119(93)90343-2.

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Pokorny, Diana, Lothar Brecker, Mateja Pogorevc, Walter Steiner, Herfried Griengl, Thomas Kappe und Douglas W. Ribbons. „Proton-Nuclear Magnetic Resonance Analyses of the Substrate Specificity of a β-Ketolase from Pseudomonas putida, Acetopyruvate Hydrolase“. Journal of Bacteriology 181, Nr. 16 (15.08.1999): 5051–59. http://dx.doi.org/10.1128/jb.181.16.5051-5059.1999.

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ABSTRACT A revised purification of acetopyruvate hydrolase from orcinol-grown Pseudomonas putida ORC is described. This carbon-carbon bond hydrolase, which is the last inducible enzyme of the orcinol catabolic pathway, is monomeric with a molecular size of ∼38 kDa; it hydrolyzes acetopyruvate to equimolar quantities of acetate and pyruvate. We have previously described the aqueous-solution structures of acetopyruvate at pH 7.5 and several synthesized analogues by1H-nuclear magnetic resonance (NMR)-Fourier transform (FT) experiments. Three 1H signals (2.2 to 2.4 ppm) of the methyl group are assigned unambiguously to the carboxylate anions of 2,4-diketo, 2-enol-4-keto, and 2-hydrate-4-keto forms (40:50:10). A1H-NMR assay for acetopyruvate hydrolase was used to study the kinetics and stoichiometries of reactions within a single reaction mixture (0.7 ml) by monitoring the three methyl-group signals of acetopyruvate and of the products acetate and pyruvate. Examination of 4-tert-butyl-2,4-diketobutanoate hydrolysis by the same method allowed the conclusion that it is the carboxylate 2-enol form(s) or carbanion(s) that is the actual substrate(s) of hydrolysis. Substrate analogues of 2,4-diketobutanoate with 4-phenyl or 4-benzyl groups are very poor substrates for the enzyme, whereas the 4-cyclohexyl analogue is readily hydrolyzed. In aqueous solution, the arene analogues do not form a stable 2-enol structure but exist principally as a delocalized π-electron system in conjugation with the aromatic ring. The effects of several divalent metal ions on solution structures were studied, and a tentative conclusion that the enol forms are coordinated to Mg2+ bound to the enzyme was made. 1H–2H exchange reactions showed the complete, fast equilibration of 2H into the C-3 of acetopyruvate chemically; this accounts for the appearance of2H in the product pyruvate. The C-3 of the product pyruvate was similarly labelled, but this exchange was only enzyme catalyzed; the methyl group of acetate did not undergo an exchange reaction. The unexpected preference for bulky 4-alkyl-group analogues is discussed in an evolutionary context for carbon-carbon bond hydrolases. Routine one-dimensional 1H-NMR in normal1H2O is a new method for rapid, noninvasive assays of enzymic activities to obtain the kinetics and stoichiometries of reactions in single reaction mixtures. Assessments of the solution structures of both substrates and products are also shown.

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Fong, K. P., C. B. Goh und H. M. Tan. „Characterization and expression of the plasmid-borne bedD gene from Pseudomonas putida ML2, which codes for a NAD+-dependent cis-benzene dihydrodiol dehydrogenase.“ Journal of bacteriology 178, Nr. 19 (1996): 5592–601. http://dx.doi.org/10.1128/jb.178.19.5592-5601.1996.

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Sutiono, Samuel, Bettina Siebers und Volker Sieber. „Characterization of highly active 2-keto-3-deoxy-L-arabinonate and 2-keto-3-deoxy-D-xylonate dehydratases in terms of the biotransformation of hemicellulose sugars to chemicals“. Applied Microbiology and Biotechnology 104, Nr. 16 (21.06.2020): 7023–35. http://dx.doi.org/10.1007/s00253-020-10742-5.

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Abstract2-keto-3-L-arabinonate dehydratase (L-KdpD) and 2-keto-3-D-xylonate dehydratase (D-KdpD) are the third enzymes in the Weimberg pathway catalyzing the dehydration of respective 2-keto-3-deoxy sugar acids (KDP) to α-ketoglutaric semialdehyde (KGSA). The Weimberg pathway has been explored recently with respect to the synthesis of chemicals from L-arabinose and D-xylose. However, only limited work has been done toward characterizing these two enzymes. In this work, several new L-KdpDs and D-KdpDs were cloned and heterologously expressed in Escherichia coli. Following kinetic characterizations and kinetic stability studies, the L-KdpD from Cupriavidus necator (CnL-KdpD) and D-KdpD from Pseudomonas putida (PpD-KdpD) appeared to be the most promising variants from each enzyme class. Magnesium had no effect on CnL-KdpD, whereas increased activity and stability were observed for PpD-KdpD in the presence of Mg2+. Furthermore, CnL-KdpD was not inhibited in the presence of L-arabinose and L-arabinonate, whereas PpD-KdpD was inhibited with D-xylonate (I50 of 75 mM), but not with D-xylose. Both enzymes were shown to be highly active in the one-step conversions of L-KDP and D-KDP. CnL-KdpD converted > 95% of 500 mM L-KDP to KGSA in the first 2 h while PpD-KdpD converted > 90% of 500 mM D-KDP after 4 h. Both enzymes in combination were able to convert 83% of a racemic mixture of D,L-KDP (500 mM) after 4 h, with both enzymes being specific toward the respective stereoisomer. Key points• L-KdpDs and D-KdpDs are specific toward L- and D-KDP, respectively.• Mg2+affected activity and stabilities of D-KdpDs, but not of L-KdpDs.• CnL-KdpD and PpD-KdpD converted 0.5 M of each KDP isomer reaching 95 and 90% yield.• Both enzymes in combination converted 0.5 M racemic D,L-KDP reaching 83% yield.

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Fong, Karen P. Y., Christopher B. H. Goh und Hai-Meng Tan. „The Genes for Benzene Catabolism in Pseudomonas putida ML2 Are Flanked by Two Copies of the Insertion Element IS1489, Forming a Class-I-Type Catabolic Transposon, Tn5542“. Plasmid 43, Nr. 2 (März 2000): 103–10. http://dx.doi.org/10.1006/plas.1999.1442.

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Majolagbe, Olusola N., Elijah A. Adebayo, Abiodun Ayandele und Louis Ezediuno. „Metalotolerance Capacity of Autochthonous Bacteria Isolated From Industrial Waste Effluent“. Annals of Science and Technology, 20.12.2017. http://dx.doi.org/10.2478/ast-2017-0003.

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Abstract Microbes play significant roles in remediation of heavy metal polluted industrial effluent using the mechanisms of biosorption and bioaccumulation. In the present study, six heavy metal resistant autochthonous bacteria species namely Bacillus cereus, B. megaterium, B. subtilis, Flavobacterium aquatile, Pseudomonas flourescens and Pseudomonas putida were isolated from effluent samples collected from Paper-mill industry (PMI), Paints and Chemicals Industry (PCI), and Steel-rolling Industry (SRI). The isolates were studied for their heavy metal tolerant capacities at different aqueous salt concentrations. Elemental analysis of the industrial effluent samples collected indicated the presence of heavy metals such as Copper (Cu2+), Manganese (Mn2+), Iron (Fe2+) and Lead (Pb2+) at varying concentrations in μg/ml. Generally, there were variations in the minimum inhibitory concentrations (MIC) of the heavy metal salt to each of the bacteria understudy. The MIC value of each of the bacterial isolates to aqueous solution of Cu2SO4 showed that B. megaterium, B. subtilis, Pseudomonas flourescens and Pseudomonas putida had the same MIC value of 20 ± 1.5 μg/mL while Bacillus cereus and Flavobacterium aquatile had MIC values of 13 ± 1.3 μg/mL and 25 ± 2.1 μg/mL respectively. This variation was also noticeable in aqueous salts of Mn2SO4, Fe2SO4 and Pb2SO4. The bacteria isolates showed sensitivity to heavy metals with increasing zone of inhibition as concentration increased with each isolate showing varying degree of metalotolerance. The effectiveness of the autochthonous bacteria as a means to bio-augment the remediation of heavy metal polluted industrial effluent was further proven and recommended.

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Xu, Zhangyang, Bo Peng, Reta Birhanu Kitata, Carrie D. Nicora, Karl K. Weitz, Yunqiao Pu, Tujin Shi, John R. Cort, Arthur J. Ragauskas und Bin Yang. „Understanding of bacterial lignin extracellular degradation mechanisms by Pseudomonas putida KT2440 via secretomic analysis“. Biotechnology for Biofuels and Bioproducts 15, Nr. 1 (31.10.2022). http://dx.doi.org/10.1186/s13068-022-02214-x.

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Abstract Background Bacterial lignin degradation is believed to be primarily achieved by a secreted enzyme system. Effects of such extracellular enzyme systems on lignin structural changes and degradation pathways are still not clearly understood, which remains as a bottleneck in the bacterial lignin bioconversion process. Results This study investigated lignin degradation using an isolated secretome secreted by Pseudomonas putida KT2440 that grew on glucose as the only carbon source. Enzyme assays revealed that the secretome harbored oxidase and peroxidase/Mn2+-peroxidase capacity and reached the highest activity at 120 h of the fermentation time. The degradation rate of alkali lignin was found to be only 8.1% by oxidases, but increased to 14.5% with the activation of peroxidase/Mn2+-peroxidase. Gas chromatography–mass spectrometry (GC–MS) and two-dimensional 1H–13C heteronuclear single-quantum coherence (HSQC) NMR analysis revealed that the oxidases exhibited strong C–C bond (β-β, β-5, and β-1) cleavage. The activation of peroxidases enhanced lignin degradation by stimulating C–O bond (β-O-4) cleavage, resulting in increased yields of aromatic monomers and dimers. Further mass spectrometry-based quantitative proteomics measurements comprehensively identified different groups of enzymes particularly oxidoreductases in P. putida secretome, including reductases, peroxidases, monooxygenases, dioxygenases, oxidases, and dehydrogenases, potentially contributed to the lignin degradation process. Conclusions Overall, we discovered that bacterial extracellular degradation of alkali lignin to vanillin, vanillic acid, and other lignin-derived aromatics involved a series of oxidative cleavage, catalyzed by active DyP-type peroxidase, multicopper oxidase, and other accessory enzymes. These results will guide further metabolic engineering design to improve the efficiency of lignin bioconversion. Graphical Abstract

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Zheng, Yanjing, Yumei Li, Hongyan Long, Xiaojuan Zhao, Keke Jia, Juan Li, Leyong Wang, Ruiyong Wang, Xiancai Lu und Dongmei Zhang. „bifA Regulates Biofilm Development of Pseudomonas putida MnB1 as a Primary Response to H2O2 and Mn2+“. Frontiers in Microbiology 9 (10.07.2018). http://dx.doi.org/10.3389/fmicb.2018.01490.

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