Plasmid-determined 2-hydroxypyridine utilization by Arthrobacter crystallopoietes.

Arthrobacter crystallopoietes has the ability to utilize 2-hydroxypyridine (2-HP) as a source of carbon and nitrogen and forms a blue extracellular pigment when grown in the presence of 2-HP. Ultracentrifugal analyses of pigment producing (Pig+) and pigment nonproducing (Pig-) strains of A. crystallopoietes revealed the presence of plasmid material in both strains. Recovery of plasmid DNA from Pig+ strains is two or three times greater than from Pig- strains. The molecular weight of plasmid DNA recovered from Pig+ strains (62 Mdaltons) is slightly higher than the molecular weight of plasmid DNA from Pig- strains. Consistent with the characterization of plasmid DNA from the two strains is that Pig+ strains contain a 63-Mdalton plasmid encoding 2-HP utilization as well as a cryptic plasmid of very nearly equal molecular weight. Pig- strains contain only the cryptic plasmid.     

Microbial metabolism of artemisitene.

Studies on the microbial transformation of the sesquiterpene endoperoxide artemisitene have revealed that artemisitene was metabolized by Aspergillus niger (NRRL 599) to yield 11-epi-artemisinin, 9 beta-hydroxydeoxy-11-epi-artemisinin and 9 beta-hydroxy-11-epi-artemisinnin. These metabolites were characterized on the basis of their spectral data.     

Microbial metabolism of 2-methyl amino acids

Eighty-nine microorganisms were isolated that were able to use 2-methyl amino acids and related compounds as the sole source of nitrogen. All of these cultures produced low levels of ammonia in culture supernatant solutions None was capable of fixing nitrogen gas. Whole-cell and cell-free-extract experiments showed that ammonia was not released directly from the 2-methyl amino acids. All of these strains except those isolated with 2-methylserine as a nitrogen source appeared to metabolize 2-methyl amino compounds by a single enzymatic reaction involving simultaneous decarboxylation and transamination. Pyruvate served as an acceptor for the transamination with the concomitant formation of alanine. The strains utilizing 2-methylserine produced a specific 2-methylserine transhydroxymethylase.     

Microbial metabolism of aliphatic glycols. Bacterial metabolism of ethylene glycol

A species of Flavobacterium isolated from pond water by its ability to grow aerobically on ethylene glycol as the role source of carbon initially oxidised the diol to glyoxylate via glycollate. The glyoxylate was metabolised by the glycerate pathway to acetyl-CoA. The acetyl-CoA was further metabolised by the tricarboxylic acid cycle plus malate synthase acting anaplerotically.     

Microbial metabolism. Part 13. Metabolites of hesperetin

The fungal culture, Mucor ramannianus (ATCC 2628) transformed hesperitin (1) to four metabolites: 4'-methoxy-5,7,8,3'-tetrahydroxyflavanone (8-hydroxyhesperetin) (2), 5,7,3',4'-tetrahydroxyflavanone (eriodictyol) (3), 4'-methoxy-5,3'-dihydroxyflavanone 7-sulfate (hesperetin 7-sulfate) (4) and 5,7,3'-trihydroxyflavanone 4'-O-α-quinovopyranoside (eriodictyol 4'-O-α-quinovopyranoside) (5). The structures were established by spectroscopic methods.     

Microbial models of mammalian metabolism. Aromatic hydroxylation

The potential for selected microorganisms to hydroxylate aromatic substrates in a manner analogous to mammalian systems has been studied. Based on literature precedence and prior experience, 11 microorganisms were chosen from among a variety of genera of fungi and bacterial species and were incubated with 13 model compounds including acetanilide, acronycine, aniline, anisole, benzene, benzoic acid, biphenyl, chlorobenzene, coumarin, naphthalene, nitrobenzene, trans-stilbene, and toluene. In most instances, the microbial model system yielded patterns of phenolic metabolites similar to those reported with cytochrome P₄₅₀ monooxygenases of hepatic microsomes and/or in vivo mammalian systems. Furthermore, N-acetylation of aniline, N-deacetylation of acetanilide, and O-demethylation of anisole were found with certain organisms. The potential usefulness of microbial systems for the synthesis of preparative quantities of mammalian metabolites of foreign organic compounds is discussed.     

Microbial metabolism of alkylbenzene sulphonates. Bacterial metabolism of undecylbenzene-p-sulphonate and dodecylbenzene-p-sulphonate

1. A study was made of the biodegradation of alkylbenzene sulphonate homologues, one of the major components of commercially marketed detergents. A Bacillus species was elected for growth on alkylbenzene sulphonate homologues as the sole source of carbon and sulphur. 2. The results from both whole-cell and cell-free systems indicated that the alkyl, aryl and sulphonate moieties of alkylbenzene sulphonate homologues were all further metabolized by the Bacillus species. 3. The alkyl side chain, after a presumed initial oxidation of the terminal methyl group, was subsequently oxidized by a beta-oxidation pathway. Three enzymes of the beta-oxidation pathway, i.e. acyl-CoA synthetase, acyl-CoA dehydrogenase and beta-hydroxyacyl-CoA dehydrogenase, were identified in cell-free extracts of the detergent-grown Bacillus species. The substrate specificity of acyl-CoA synthetase indicated activity towards several alkylbenzene sulphonate homologues. 4. The sulphonate moiety was released as sulphite by a desulphonating enzyme. Some kinetic properties of this enzyme were determined. The sulphite was subsequently metabolized to either sulphate or adenosine 5'-sulphatophosphate. Two enzymes involved in sulphite metabolism, i.e. sulphite-cytochrome c reductase and adenosine 5'-sulphatophosphate-cytochrome c reductase were detected in cell-free extracts of undecylbenzene-p-sulphonate-grown Bacillus species. 5. The combined results of continuous sampling programmes monitored by both t.l.c. and sulphite appearance in the growth medium indicated that desulphonation of the aromatic moiety was the likely first step in the overall biodegradation of several alkylbenzene sulphonate homologues. 6. The presence of p-hydroxyphenylpropionate, p-hydroxybenzoate and 3,4-dihydroxybenzoate in cells after growth on several alkylbenzene sulphonate homologues containing an odd number of carbon atoms in the side chain was confirmed by g.l.c. and t.l.c. analysis. Cells grown on several homologues containing an even number of carbon atoms in the side chain were shown to contain p-hydroxyphenylacetate and 3,4-dihydroxyphenylacetate. 7. The aromatic nucleus obtained from undecylbenzene-p-sulphonate was further metabolized by an oxidation sequence involving an ;ortho-cleavage' route. 8. An overall metabolic pathway for the biodegradation of various alkylbenzene sulphonate homologues by this Bacillus species is proposed.     

Microbial metabolism of ethylene

The ethylene-oxidizing strain E20 was grown on different carbon sources to obtain information on the metabolism of ethylene from simultaneous adaptation studies and from measurements of specific activities of enzymes in cell-free extracts.From the simultaneous adaptation studies it was concluded that ethylene oxide is a product of ethylene catabolism. The bacterium was also able to grow on the epoxide. From a comparison of the specific activities of isocitrate lyase and malate synthetase in different extracts it was concluded that the glyoxylate cycle was involved in the metabolism of ethylene, indicating that acetyl-CoA is a metabolite of ethylene catabolism. The sequence of reactions leading from ethylene oxide to acetyl-CoA could not be established from the simultaneous adaptation experiments and the enzyme activities in extracts.Support for the research has come in part from grants of the N.V. Nederlandse Gasunie and the VEG Gasinstituut.     

Microbial metabolism of pyrene

The isolation and identification of pyrene metabolites formed from pyrene by the fungus Cunninghamella elegans is described. C. elegans was incubated with pyrene for 24 h. Six metabolites were isolated by reversed-phase high-performance liquid (HPLC) and thin-layer chromatography (TLC) and characterized by the application of UV absorption, 1H-NMR and mass spectral techniques. C. elegans hydroxylated pyrene predominantly at the 1,6- and 1,8-positions with subsequent glucosylation to form glucoside conjugates of 1-hydroxypyrene, 1,6- and 1,8-dihydroxypyrene. In addition, 1,6- and 1,8-pyrenequinones and 1-hydroxypyrene were identified as metabolites. Experiments with [4-14C]pyrene indicated that over a 24-h period, 41% of pyrene was metabolized to ethyl acetate-soluble metabolites. The glucoside conjugates of 1-hydroxypyrene, 1,6- and 1,8-dihydroxypyrene accounted for 26%, 7% and 14% of the pyrene metabolized, respectively. Pyrenequinones accounted for 22%. The results indicate that the fungus C. elegans metabolized pyrene to non-toxic metabolites (glucoside conjugates) as well as to compounds (pyrenequinones) which have been suggested to be biologically active in higher organisms. In addition, there was no metabolism at the K-region of the molecule which is a major site of enzymatic attack in mammalian systems.     

Studies on the activity of three palladium(II) compounds of the form: trans-PdL2Cl2 where L=2-hydroxypyridine, 3-hydroxypyridine, and 4-hydroxypyridine

Three planaraminepalladium(II) complexes of the form: trans-PdCl(2)L(2), code named TH5, TH6 and TH7 where L=3-hydroxypyridine, 2-hydroxypyridine and 4-hydroxypyridine respectively have been investigated for antitumour activity against ovarian cancer cell lines: A2780, A2780(cisR) and A2780(ZD0473R). Although the compounds are generally found to be less active than cisplatin, they are often found to be more active against the resistant cell lines than the parent cell line. Among TH5, TH6 and TH7, TH6 which has two 2-hydroxypyridine non-labile ligands is found to be most active against the three cell lines. Variations in activity of TH5, TH6 and TH7 indicate that non-covalent interactions may be playing a significant role in activity. In particular, the results indicate that small changes in planaramine ligands such as the position of the polar OH group can have a more profound effect on activity of the compounds. Palladium compounds are generally found to be toxic rather tumour active because of much higher reactivity. Low but significant activity of trans-palladium(II) complexes TH5, TH6 and TH7 against the ovarian cancer cell lines indicates that it is believed to be associated with the decrease in their reactivity due to the presence of two sterically hindered planaramine ligands.     

A crystalline pigment produced from 2-hydroxypyridine by arthrobacter crystallopoietes n.sp.

Summary A bacterium was isolated from soil which utilizes 2-hydroxypyridine as sole source of carbon and nitrogen. When grown on solid medium with this substrate massive amounts of green rectangular crystals are deposited extracellularly in the colony mass. The pigment producing organism proved to be a hitherto undescribed species to which the name Arthrobacter crystallopoietes was applied. The pigment formed is characterized qualitatively by the following properties: it is an oxidation product of 2-hydroxypyridine probably still containing a six-membered heterocyclic ring; it exists as an anion with an intense blue color in neutral or slightly alkaline solution and as a metal salt in the deposited crystals; it precipitates from acid solution as a red water-insoluble free acid; it can be reversible oxidized and reduced, being colorless in the reduced form; and in solution it is spontaneously oxidized by air, the reaction being very rapid at alkalineph. The ultraviolet, visible and infrared spectra of the blue and red forms are presented. The properties of the pigment show that it is a member of a chemically poorly defined group of compounds termed azaquinones and that it is related to but not identical with pigments produced by the bacterial oxidation of nicotine, nicotinic acid and isonicotinic acid.This investigation was supported in part by grants G9882 and GB736 from the National Science Foundation.     

Microbial metabolism of amino alcohols. Aminoacetone metabolism via 1-aminopropan-2-ol in Pseudomonas sp. N.C.I.B. 8858

1. Pseudomonas sp. N.C.I.B. 8858 grew well on d- and l-1-aminopropan-2-ol and on aminoacetone. 2. Cell-free extracts possessed high activities of inducibly formed l-1-aminopropan-2-ol-NAD(+) oxidoreductase, amino alcohol-ATP phosphotransferase, dl-1-aminopropan-2-ol O-phosphate phospho-lyase and aldehyde-NAD(+) oxidoreductase, but no 1-aminopropan-2-ol racemase or d-1-aminopropan-2-ol-NAD(+) oxidoreductase. 3. The amino alcohol kinase (activated by ADP) was non-stereospecific towards 1-aminopropan-2-ol and was one-third as active with ethanolamine. The phospho-lyase was active with l- and d-1-aminopropan-2-ol O-phosphate, but ethanolamine O-phosphate was only one-tenth as active as its higher homologues. The purified aldehyde dehydrogenase was active with propionaldehyde, acetaldehyde and also with methylglyoxal. The previously observed 2-oxo aldehyde dehydrogenase activity was considered to be due to the broadly specific aldehyde dehydrogenase. 4. Mutants of Pseudomonas sp. N.C.I.B. 8858 deficient in 1-aminopropan-2-ol kinase, 1-aminopropan-2-ol O-phosphate phospho-lyase, aldehyde dehydrogenase or an enzyme involved in propionate metabolism were incapable of growth on aminoacetone or 1-aminopropan-2-ol as carbon source, although all except the kinase- or phospho-lyasedeficient mutants could use these compounds and ethanolamine as nitrogen sources. The aldehyde dehydrogenase-deficient mutants produced copious amounts of propionaldehyde and acetaldehyde during growth on the corresponding amino alcohols. 5. The path of aminoacetone metabolism in Pseudomonas sp. N.C.I.B. 8858 was concluded to involve l-1-aminopropan-2-ol, the O-phosphate ester of this compound, propionaldehyde and propionate as obligatory intermediates. d-1-Aminopropan-2-ol was metabolized by the same route as the l-isomer, gratuitously inducing formation of the stereospecific l-1-aminopropan-2-ol dehydrogenase. 6. Extracts of the pseudomonad grown with ethanolamine as the nitrogen source were devoid of 1-aminopropan-2-ol dehydrogenase, the kinase and the phospho-lyase, but exhibited cobamide coenzyme-dependent deaminase activity. Mutants deficient in kinase or phospho-lyase (deaminating) grew well on ethanolamine as the nitrogen source. Ethanolamine deaminase was inactive with, but inhibited by, 1-aminopropan-2-ol.