Showing papers on "Pseudomonas putida published in 1984"
TL;DR: Rates of inactivation by 3-fluorocatechol were reduced in the presence of superoxide dismutase, catalase, formate, and mannitol, which implies that superoxide anion, hydrogen peroxide, and hydroxyl radical exhibit additional inactivation.
Abstract: The inactivation of catechol 2,3-dioxygenase from Pseudomonas putida mt-2 by 3-chloro- and 3-fluorocatechol and the iron-chelating agent Tiron (catechol-3,5-disulfonate) was studied. Whereas inactivation by Tiron is an oxygen-independent and mostly reversible process, inactivation by the 3-halocatechols was only observed in the presence of oxygen and was largely irreversible. The rate constants for inactivation (K2) were 1.62 × 10−3 sec−1 for 3-chlorocatechol and 2.38 × 10−3 sec−1 for 3-fluorocatechol. The inhibitor constants (Ki) were 23 μM for 3-chlorocatechol and 17 μM for 3-fluorocatechol. The kinetic data for 3-fluorocatechol could only be obtained in the presence of 2-mercaptoethanol. Besides inactivated enzyme, some 2-hydroxyhexa-2,4-diendioic acid was formed from 3-chlorocatechol, suggesting 5-chloroformyl-2-hydroxypenta-2,4-dienoic acid as the actual suicide product of meta-cleavage. A side product of 3-fluorocatechol cleavage is a yellow compound with the spectral characteristics of a 2-hydroxy-6-oxohexa-2,4-dienoic acid indicating 1,6-cleavage. Rates of inactivation by 3-fluorocatechol were reduced in the presence of superoxide dismutase, catalase, formate, and mannitol, which implies that superoxide anion, hydrogen peroxide, and hydroxyl radical exhibit additional inactivation.
336 citations
TL;DR: A silver-resistant strain of Pseudomonas stutzeri was isolated from a silver mine and harbored three plasmids, the largest of which (pKK1; molecular weight, 49.4 X 10(6)) specified silver resistance.
Abstract: A silver-resistant strain of Pseudomonas stutzeri was isolated from a silver mine. It harbored three plasmids, the largest of which (pKK1; molecular weight, 49.4 X 10(6)) specified silver resistance. Plasmid pKK1 was apparently nonconjugative but could be transferred to Pseudomonas putida by mobilization with plasmid R68.45. Images
250 citations
TL;DR: The results of amino acid analyses and of ultraviolet, circular dichroism, electron paramagnetic resonance, and Cadmium-113 nuclear magnetic resonance spectroscopy suggest a novel cadmium( II)-zinc(II)-copper(I) cluster structure for the major protein.
Abstract: Three cysteine-rich proteins of molecular weight 4000 to 7000, containing 4 to 7 gram atoms of cadmium, zinc, and copper per mole were isolated from Pseudomonas putida growing in 3 mM cadmium. The three proteins were induced during different phases of growth, and the smallest (molecular weight 3600; 3 gram atoms of cadmium) was released into the medium when the cells lysed. The results of amino acid analyses and of ultraviolet, circular dichroism, electron paramagnetic resonance, and cadmium-113 nuclear magnetic resonance spectroscopy suggest a novel cadmium(II)-zinc(II)-copper(I) cluster structure for the major protein.
171 citations
140 citations
TL;DR: The results indicated that P. putida markedly increased nodulation compared to R. phaseoli controls, which could imply an increased P supply to roots of P. vutgaris , which may function to increase nodules.
Abstract: The effect of Pseudomonas putida (isolate M17) on Rhizobium phaseoli nodulation of the common bean, Phaseolus vulgaris , was investigated under field and greenhouse conditions. The results indicated that P. putida markedly increased nodulation compared to R. phaseoli controls. Furthermore, 2-ketogluconic acid, a phosphate-solubiliring compound, was detected in P. putida M17. This could imply an increased P supply to roots of P. vutgaris , which may function to increase nodules. Bean yields and shoot fresh weight were not significantly altered by the addition of P. putida M17.
123 citations
TL;DR: DNA fragments containing the xylD and xylL genes of TOL plasmid pWW0 -161 of Pseudomonas putida, which code for the catabolic enzymes toluate 1,2-dioxygenase and dihydrodihydroxybenzoic acid dehydrogenase, and the nahG gene of the NAH plasmids NAH7, which codes for salicylate hydroxylase, were cloned in p
Abstract: DNA fragments containing the xylD and xylL genes of TOL plasmid pWW0 -161 of Pseudomonas putida, which code for the catabolic enzymes toluate 1,2-dioxygenase and dihydrodihydroxybenzoic acid dehydrogenase, respectively, and the nahG gene of the NAH plasmid NAH7 , which codes for salicylate hydroxylase, were cloned in pBR322 vector plasmid. Deletion and insertion mutagenesis were used to localize these genes with respect to crucial endonuclease cleavage sites. The pBR322-based plasmids were ligated to the broad host range cloning vector pKT231 , or derivatives of it, and the hybrid plasmids were introduced into Pseudomonas sp. B13( WR1 ), a bacterium able to degrade 3-chlorobenzoate but not 4-chlorobenzoate, 3,5- dichlorobenzoate , salicylate, or chlorosalicylates . The cloned xylD gene expanded the catabolic range of WR1 to include 4-chlorobenzoate, whereas the cloned xylD - xylL genes enabled the isolation of derivatives of WR1 that degraded 3-chlorobenzoate, 4-chlorobenzoate, and 3,5- dichlorobenzoate . The cloned nahG gene extended the catabolic range of WR1 to include salicylate and 3-, 4-, and 5- chlorosalicylate .
114 citations
TL;DR: In this article, two overlapping promoters, designated Pm1 and Pm2, are responsible for the positively regulated expression of the meta-pathway operon of Pseudomonas putida.
Abstract: Expression of the meta-cleavage pathway operon of TOL plasmid pWW0 of Pseudomonas putida is positively regulated by the xylS gene product. We have sequenced the promoter region of this operon and localized the transcription initiation sites. Two overlapping promoters, designated Pm1 and Pm2, are responsible for the positively regulated expression of the meta-pathway operon. Mutants of P. putida were isolated that expressed the meta-cleavage pathway operon constitutively. Several plasmid-located mutations that led to constitutivity were characterized by sequencing and the transcription initiation sites on mutant plasmids localized. This resulted in the identification of newly created promoters whose functioning did not require the xylS product. Comparison of the promoter sequences obtained suggests a tentative consensus sequence for promoters of P. putida which is significantly different from that of E. coli.
110 citations
TL;DR: The xylABC operon on the TOL plasmid directs the synthesis of enzymes for conversion of toluene to benzoate and is positively controlled by the regulatory gene xylR, and the nucleotide sequence was determined for the regulatory region of this operon.
Abstract: The xylABC operon on the TOL plasmid directs the synthesis of enzymes for conversion of toluene to benzoate and is positively controlled by the regulatory gene xylR. In the study here the nucleotide sequence was determined for the regulatory region of this operon. The in vivo transcription initiation site of the operon was determined by S1 nuclease and reverse transcriptase mapping. RNA was prepared from m-methylbenzyl alcohol-induced cells of Pseudomonas putida and Escherichia coli carrying pTN2, a derivative of the TOL plasmid containing the structural and regulatory genes of the entire toluene-degrading pathway. The amount of E. coli mRNA was estimated to be only 10% of that of P. putida mRNA. Consensus sequences of the -10 region (Pribnow box) and the -35 region (RNA polymerase recognition site) in E. coli genes were not found in the region preceding the transcription initiation site, whereas a sequence complementary to the 3' end of the 16S rRNA of Pseudomonas aeruginosa and E. coli existed in front of the predicted start codon of the xylA gene. These results explain the inefficient expression of TOL genes in E. coli.
109 citations
TL;DR: Results show that P. putida synthesizes at least two distinct chemoreceptors for aromatic acids, and DL-mandelate was an effective attractant in capillary assays, but additional experiments indicated that the cells were actually responding to benzoylformate, a metabolite formed from mandelate.
Abstract: A quantitative capillary assay was used to show that aromatic acids, compounds that are chemorepellents for Escherichia coli and Salmonella sp., are chemoattractants for Pseudomonas putida PRS2000. The most effective attractants were benzoate; p-hydroxybenzoate; the methylbenzoates; m-, p-, and o-toluate; salicylate; DL-mandelate; beta-phenylpyruvate; and benzoylformate. The chemotactic responses to these compounds were inducible. Taxis to benzoate and m-toluate was induced by beta-ketoadipate, a metabolic intermediate formed when benzoate is dissimilated via enzymes specified by chromosomal genes. Benzoylformate taxis was induced by benzoylformate and L(+)-mandelate. Taxis to mandelate, benzoylformate, and beta-phenylpyruvate was exhibited by cells grown on mandelate, but not by cells grown on benzoate. Cells grown on benzoate were chemotactic to benzoate, the toluates, p-hydroxybenzoate, and salicylate. These results show that P. putida synthesizes at least two distinct chemoreceptors for aromatic acids. Although DL-mandelate was an effective attractant in capillary assays, additional experiments indicated that the cells were actually responding to benzoylformate, a metabolite formed from mandelate. With the exception of mandelate taxis, chemotaxis to aromatic acids was not dependent on the expression of pathways for aromatic degradation. Therefore, the tactic responses exhibited by cells cannot be attributed to an effect of the oxidation of aromatic acids on the energy metabolism of cells.
105 citations
TL;DR: Between 40 and 60% of the putative mutants selected from the NBT-TTC indicator plates were unable to grow with toluene as the sole source of carbon and energy, which should prove extremely useful in isolating mutants in other multicomponent oxygenase enzyme systems.
Abstract: Pseudomonas putida PpF1 degraded toluene via a dihydrodiol pathway to tricarboxylic acid cycle intermediates. The initial reaction was catalyzed by a multicomponent enzyme, toluene dioxygenase, which oxidized toluene to (+)-cis-1(S),2(R)-dihydroxy-3-methylcyclohexa-3,5-diene (cis-toluene dihydrodiol). The enzyme consisted of three protein components: NADH-ferredoxintol oxidoreductase (reductasetol), ferredoxintol, and a terminal oxygenase which is an iron-sulfur protein (ISPtol). Mutants blocked in each of these components were isolated after mutagenesis with nitrosoguanidine. Mutants occurred as colony morphology variants when grown in the presence of toluene on indicator plates containing agar, mineral salts, a growth-supporting nutrient (arginine), 2,3,5-triphenyltetrazolium chloride (TTC), and Nitro Blue Tetrazolium (NBT). Under these conditions, wild-type colonies appeared large and red as a result of TTC reduction. Colonies of reductasetol mutants were white or white with a light blue center, ferredoxintol strains were light blue with a dark blue center, and strains that lacked ISPtol gave dark blue colonies. Blue color differences in the mutant colonies were due to variations in the extent of NBT reduction. Strains lacking all three components appeared white. Toluene dioxygenase mutants were characterized by assaying toluene dioxygenase activity in crude cell extracts which were complemented with purified preparations of each protein component. Between 40 and 60% of the putative mutants selected from the NBT-TTC indicator plates were unable to grow with toluene as the sole source of carbon and energy. This method should prove extremely useful in isolating mutants in other multicomponent oxygenase enzyme systems.
104 citations
TL;DR: The transcription initiation site of the xylDEGF operon on the TOL plasmid of Pseudomonas putida mt-2 was determined in P. putida and in Escherichia coli by S1 nuclease and reverse transcriptase mapping.
TL;DR: The signal from the dioxygenase shows pronounced g anisotropy and most closely resembles those of 4-methoxybenzoate mono-oxygenase from Pseudomonas putida and the [2Fe-2S] 'Rieske' proteins of the quinone-cytochrome c region of electron-transport chains of respiration and photosynthesis.
Abstract: Benzene dioxygenase from Pseudomonas putida comprises three components, namely a flavoprotein (NADH:ferredoxin oxidoreductase; Mr 81000), an intermediate electron-transfer protein, or ferredoxin (Mr 12000) with a [2Fe-2S] cluster, and a terminal dioxygenase containing two [2Fe-2S] iron-sulphur clusters (Mr 215000), which requires two additional Fe2+ atoms/molecule for oxygenase activity. The ferredoxin and the dioxygenase give e.s.r. signals in the reduced state with rhombic symmetry and average g values of 1.92 and 1.896 respectively. The mid-point redox potentials were determined by e.s.r. titration at pH 7.0 to be -155 mV and -112 mV respectively. The signal from the dioxygenase shows pronounced g anisotropy and most closely resembles those of 4-methoxybenzoate mono-oxygenase from Pseudomonas putida and the [2Fe-2S] 'Rieske' proteins of the quinone-cytochrome c region of electron-transport chains of respiration and photosynthesis.
TL;DR: The present enzyme has a multicatalytic function similar to the enzyme of P. putida IFO 3738 and shows the typical absorption spectrum of pyridoxal enzyme with maxima at 278 and 420 nm, and contains 4 mol of prydoxal 5′-phosphate per mole of enzyme.
TL;DR: Etude de la survie, en sol non sterile, de P.p., capable d'induire la suppression of the Fusarium.
Abstract: Etude de la survie, en sol non sterile, de P.p., capable d'induire la suppression de Fusarium
TL;DR: The utilization of arginine was studied in several different Pseudomonas species; agmatine catabolism seemed to follow an unusual route involving guanidinobutyrate as intermediate.
Abstract: SUMMARY: The utilization of arginine was studied in several different Pseudomonas species. The arginine decarboxylase and agmatine deiminase pathways were found to be characteristic of Pseudomonas species of group I as defined by Palleroni et al. (1974). Pseudomonas putida strains had three distinct arginine catabolic pathways initiated by arginine decarboxylase, arginine deiminase and arginine oxidase, respectively. The two former routes were also present in P. fluorescens and P. mendocina and in P. aeruginosa which also used arginine by a further unknown pathway. None of these pathways occurred in P. cepacia strains; agmatine catabolism seemed to follow an unusual route involving guanidinobutyrate as intermediate.
TL;DR: A novel coenzyme, PQQ, was reported as a bacterial growth factor for the first time, effective in causing growth of the PVA-degrading bacterium on PVA but also in enhancing the growth rate and the cell yield at concentrations of 0.05 to 4ng/ml.
Abstract: From a supernatant of a mixed continuous culture of Pseudomonas sp. VM15C and Pseudomonas putida VM15A, of which the former produced a poly(vinyl alcohol) (PVA)-degrading enzyme and the latter an essential growth factor (trivial name, factor A) for PVA utilization by the former, purified factor A showing homogeneity on high performance liquid chromatography was obtained. From spectral and other evidence, factor A was identified as pyrroloquinoline quinone (PQQ). PQQ was effective in not only causing growth of the PVA-degrading bacterium on PVA but also in enhancing the growth rate and the cell yield at concentrations of 0.05 to 4ng/ml. Thus, a novel coenzyme, PQQ, was reported as a bacterial growth factor for the first time.
TL;DR: The maximum amount of histamine produced by a single isolate was 3.2 mg/100 ml, far below the minimum level of 50mg/100 g believed necessary to induce symptoms of Histamine toxicity.
TL;DR: Strains of Caulobacter crescentus, Pseudomonas putida, Acinetobacter calcoaceticus, Rhizobium meliloti, and Rhodopseudomona sphaeroides carrying the kanamycin resistance-encoding transposon Tn5 were 15 to 500 times more resistant to streptomycin than transposons-free strains.
Abstract: Strains of Caulobacter crescentus, Pseudomonas putida, Acinetobacter calcoaceticus, Rhizobium meliloti, and Rhodopseudomonas sphaeroides carrying the kanamycin resistance-encoding transposon Tn5 were 15 to 500 times more resistant to streptomycin than transposon-free strains. The streptomycin resistance determinant, which is separable from the kanamycin resistance determinant of Tn5, was not expressed in Escherichia coli or Klebsiella aerogenes.
TL;DR: Enzymic hydroxylation of 4-ethylphenol by Pseudomonas putida and highly purified p-cresol methylhydroxylase gave optically active 1-(4'-hydroxyphenyl)-ethanol, which was transformed into the phenolic methyl ethers and shown to contain 69.5% and 65.6% of the (S)-(-)-isomer.
Abstract: Enzymic hydroxylation of 4-ethylphenol by (a) Pseudomonas putida and (b) highly purified p-cresol methylhydroxylase gave optically active 1-(4′-hydroxyphenyl)-ethanol. The products were transformed into the phenolic methyl ethers and shown to contain 69.5% and 65.6%, respectively, of the (S)-(-)-isomer. The stereochemistry of the reaction is discussed in terms of three distinct steps occurring at the active site of the enzyme.
TL;DR: Results indicate that LPD-glc is specifically utilized for glycine oxidation in P. putida, and was five times as active as L PD-val in catalyzing the oxidation of purified protein H, the heat-stable, lipoic acid-containing protein of the glycine oxide system.
TL;DR: Biochemical and restriction endonuclease analysis of the wild-type and mutant strains showed that the structural and/or regulatory genes for 3,5-xylenol metabolism were encoded within a 130–140 kb region of pRA500.
Abstract: SUMMARY: Pseudomonas putida NCIB 9869 carries a transmissible plasmid pRA500 of approximately 500 kb which encodes the degradation of 3,5-xylenol via a gentisate pathway. Several mutant strains which were unable to utilize 3,5-xylenol were isolated and these strains either carried deleted derivatives of pRA500 or lacked plasmid DNA. Biochemical and restriction endonuclease analysis of the wild-type and mutant strains showed that the structural and/or regulatory genes for 3,5-xylenol metabolism were encoded within a 130–140 kb region of pRA500 and that, with the exception of the first enzyme of the pathway, 3,5-xylenol methylhydroxylase, all the enzymes were encoded within a 50–70 kb segment of that region. pRA500 also encoded for resistance to inorganic mercuric ions; the genes for this phenotype were located separately from those for the degradation of 3,5-xylenol.
TL;DR: It is concluded that the two RNA polymerases have very similar structures of DNA binding centers and the evolutionary conservation of this structure may account for the fact that diverse RNA polymerase often recognize and efficiently use promoters of distant bacterial species.
Abstract: Methylation protection experiments with four promoters (P1 and P2 of the pBR322 plasmid, lacUV5 and lambda P0) have shown that the RNA polymerases from Escherichia coli and Pseudomonas putida, while differing in the primary structure of the subunits involved in DNA binding, display identical patterns of DNA contacts. Nor do these enzymes differ in covalent cross-linking patterns with a partially apurinized promoter. We conclude that the two RNA polymerases have very similar structures of DNA binding centers. The evolutionary conservation of this structure may account for the fact that diverse RNA polymerases often recognize and efficiently use promoters of distant bacterial species.
TL;DR: The results suggest that an intrinsic zinc and sulfhydryl group together with NAD+ participate in the dehydrogenation reaction of substrate by the enzyme.
Abstract: The NAD+-dependent formaldehyde dehydrogenase from Pseudomonas putida C-83 was found to contain 4 gram atoms of zinc per mol, corresponding to 2 gram atoms of zinc per subunit monomer. Treatment of the enzyme with o-phenanthroline resulted in removal of 1 gram atom of zinc per subunit and caused a complete inactivation of the enzyme. The activity lost was restored by the addition of zinc ions, by which the zinc content was also reversed to almost the same level as that of the native enzyme. Another zinc atom that was resistant to metal chelator-treatment was liberated from the enzyme only after the irreversible denaturation of the enzyme. These results indicate that the formaldehyde dehydrogenase of P. putida is a zinc metalloenzyme and one of two zinc atoms per subunit participates in the catalytic activity of the enzyme, another zinc being presumably involved in maintaining the native conformation of the enzyme. Treatment of the enzyme with bipyridine also caused a reversible inactivation of the enzyme, but the zinc content remained unchanged. The spectrophotometric analysis indicated that the formation of a enzyme-Zn-bipyridine complex took place. Incubation of the enzyme with p-chloromercuribenzoate also resulted in a complete loss of the activity. These results suggest that an intrinsic zinc and sulfhydryl group together with NAD+ participate in the dehydrogenation reaction of substrate by the enzyme.
TL;DR: Two forms of formaldehyde dismutase distinguishable on disc-gel electrophoresis were isolated from the cell-free extract of Pseudomonas putida F61 and the COOH-terminal amino acid sequence was found to be -Ser-Gly-Lys.
Abstract: Two forms of formaldehyde dismutase distinguishable on disc-gel electrophoresis were isolated from the cell-free extract of Pseudomonas putida F61. The mobilities on SDS-gel electrophoresis and the NH2-terminal amino acids (arginine) of the two enzyme species were identical. The COOH-terminal amino acid sequence was found to be -Ser-Gly-Lys. The enzyme was inhibited by carbonyl, reducing and sulfhydryl reagents.The enzyme catalyzed the cross-dismutation reaction between formaldehyde and an aldehyde, such as propionaldehyde, acrolein, butyraldehyde, isobutyraldehyde and crotonaldehyde. The enzyme also catalyzed a coupled oxidoreduction between an alcohol and an aldehyde (RCH2OH+R'CHO RCHO +R'CH2OH) without addition of an electron acceptor. Aliphatic alcohols and aldehydes of C2 to C4 were utilized in this reaction.
TL;DR: The method is effective for the rapid, simultaneous analysis of the major keto compounds in blood and may prove useful in the study of energy metabolism and clinical biochemistry and provide evidence that the method is capable of valid measurements of metabolic variables.
Abstract: buffer (v/v), pH7.4, for 5min followed by a linear gradient up to 100% methanol over 10min. An integrator was used for quantitative analysis. The chromatographic conditions described separated, in order of elution, pyruvate, acetoacetate and acetone (Fig. la), and gave a linear response over the physiological range Of 40-lOOpM. Pyruvate ( 8 0 ~ ~ ) gave 6 times the colour yield of acetoacetate and 11 times the colour yield of acetone at the same concentration. Alloxan-diabetic rats (Howell &Taylor, 1967) showed the expected increased blood levels of pyruvate, acetoacetate and acetone over normal rats. They showed a reduced level of an unidentified keto compound, labelled 'X' in Fig. l(b), compared with normal ones. The method is effective for the rapid, simultaneous analysis of the major keto compounds in blood and may prove useful in the study of energy metabolism and clinical biochemistry. Results using normal, starved and alloxandiabetic rats conform to current understanding of these metabolic models (White et al., 1984) and provide evidence that the method is capable of valid measurements of metabolic variables.
01 Jan 1984
TL;DR: In choosing an enzyme of Pseudomonas aeruginosa as the starting point for studies in experimental evolution, the well-known biochemical versatility of this genus was thought to have been in mind.
Abstract: In choosing an enzyme of Pseudomonas aeruginosa as the starting point for studies in experimental evolution, we had in mind the well-known biochemical versatility of Pseudomonas species. Many catabolic pathways had been described in detail for species belonging to this genus, and biochemists interested in isolating strains that could attack unusual organic compounds had often found that the isolates obtained from enrichment cultures could be assigned to the Pseudomonas group. A very comprehensive survey of laboratory strains carried out 60 years ago by Den Dooren De Jong (1926) had pointed to Pseudomonas putida as a particularly versatile organism. He found that one of his strains could utilize about 80 of 200 test compounds as the sole carbon source for growth. Among the compounds used in Den Dooren De Jong’s experiments were the sodium salts of bromosuccinic and α- and β-bromopropionic acids. These compounds were laboratory chemicals, and it could be asked whether they were attacked by enzymes with very wide substrate specificities that could not distinguish between halogenated and nonhalogenated substrates or whether there were specific enzymes that had evolved to act on organic compounds that occur rarely if at all in nature. Such questions become particularly pertinent when it is realized that during the last century the activities of the chemical industry have released many synthetic chemicals into the natural environment.
TL;DR: Growth conditions that elicited positive chemotaxis to benzoate and m-toluate in T OL- Pseudomonas putida cells failed to elicit taxis to these compounds in TOL+ cells, due to the preferential expression of TOL-encoded genes for aromatic degradation over chromosomally encoded genes.
Abstract: Growth conditions that elicited positive chemotaxis to benzoate and m-toluate in TOL- Pseudomonas putida cells failed to elicit taxis to these compounds in TOL+ cells. The inability of TOL+ cells to respond to these aromatic acids appears to be due to the preferential expression of TOL-encoded genes for aromatic degradation over chromosomally encoded genes. Expression of chromosomal genes for aromatic degradation is required for cells to form beta-ketoadipate, the inducer of benzoate and m-toluate taxis.
TL;DR: The results indicated that the growth-limiting substrate for strain VM15C in the mixed continuous culture is the growth factor produced by strainVM15A, the primary metabolizer of PVA.
Abstract: Stable mixed continuous cultures of Pseudomonas sp. strain VM15C and Pseudomonas putida VM15A, the former of which produced a polyvinyl alcohol (PVA)-degrading enzyme and the latter of which produced an essential growth factor for PVA utilization by strain VM15C, were established with PVA as the sole source of carbon and energy with chemostat cultivation. A high extent of PVA degradation was achieved at dilution rates of less than 0.030/h. The predominant strain in the cultures was the primary metabolizer of PVA, strain VM15C. The growth supporter, strain VM15A, existed as a minor population, although its population was maintained at an almost constant level throughout a dilution region in which the VM15C population decreased markedly as the dilution rate was raised. A crude growth factor which was prepared from a culture supernatant of strain VM15A and increased the specific growth rate of strain VM15C with PVA in an axenic batch culture was also effective for enhancing the VM15C population and PVA degradation in the mixed continuous culture at a high dilution rate (0.064/h). This indicated that the growth-limiting substrate for strain VM15C in the mixed continuous culture is the growth factor produced by strain VM15A.
TL;DR: The substrate specificity of formaldehyde dehydrogenase purified from a cell-free extract of Pseudomonas putida C-83 was reinvestigated with a series of aldehyde and alcohol substrates as discussed by the authors.
Abstract: The substrate specificity of formaldehyde dehydrogenase purified from a cell-free extract of Pseudomonas putida C-83 was reinvestigated with a series of aldehyde and alcohol substrates. The activities toward formaldehyde and n-butanol were almost parallel throughout the procedures of enzyme purification and pH-stability experiments, suggesting that the same enzyme protein shows dehydrogenase activities for both aldehyde and alcohol substrates. Formaldehyde was the best substrate and the enzyme showed reduced activity with increasing length of alkyl groups of aldehydes, no activity being detected for n-butyraldehyde. Among the alcohol substrates, n-pentanol was the best substrate, and no activity was observed for methanol or ethanol. The enzyme activity for alcohols increased with increasing length of alkyl groups until n-pentanol and then decreased gradually. The dehydrogenase activity toward formaldehyde was inhibited competitively by other aldehydes but noncompetitively by n-butanol and n-hexanol. On th...