Specificity and Induction of Undecyl Acetate Esterase from Pseudomonas cepacia Grown on 2-Tridecanone

Undecyl acetate esterase from Pseudomonas cepacia grown on 2-tridecanone was strongly inhibited by organophosphates and other esterase inhibitors. Also, p-chloromercuribenzoate at 1 × 10(−4) M showed a 70% inhibition of esterase activity. The enzyme hydrolyzed both aliphatic and aromatic acetate esters at substrate concentrations of 0.25 M. Under these conditions the highest reaction rate was toward undecyl acetate. No lipase or proteolytic activity was demonstrated. Undecyl acetate esterase was classified as a carboxylesterase (B-esterase). Cell-free activity studies on the production of undecyl acetate esterase grown on different carbon sources plus zymogram studies demonstrated that the enzyme was inducible when 2-tridecanone, 2-tridecanol, undecyl acetate and, to a lesser extent, 1-undecanol were growth substrates. Induction of undecyl acetate esterase during oxidation of 2-tridecanone supports the view that undecyl acetate is an intermediate in the degradation of the methyl ketone

Degradation of Hydrocarbons by Members of the Genus Candida: I. Hydrocarbon Assimilation

A representative number of species of the genus Candida were tested for their ability to utilize n-alkanes of 9 to 18 carbon atoms and even-numbered 1-alkenes of 10 to 18 carbon atoms. A high percentage of these organisms exhibited the ability to assimilate some member of the hydrocarbon series employed. These findings indicate that the ability to assimilate hydrocarbons is not limited to a few species of the genus and may be of some taxonomic significance

Degradation of Hydrocarbons by Members of the Genus Candida II. Oxidation of n-Alkanes and 1-Alkenes by Candida lipolytica

Candida lipolytica ATCC 8661 was grown in a mineral-salts hydrocarbon medium. n-Alkanes and 1-alkenes with 14 through 18 carbon atoms were used as substrates. Ether extracts of culture fluids and cells obtained from cultures grown on the various substrates were analyzed by thin-layer and gas-liquid chromatography. Analyses of fluids from cultures grown on n-alkanes indicated a predominance of fatty acids and alcohols of the same chain length as the substrate. In addition, numerous other fatty acids and alcohols were present. Analyses of saponifiable and nonsaponifiable material obtained from the cells revealed essentially the same products. The presence of primary and secondary alcohols, as well as fatty acids, of the same chain length as the n-alkane substrate suggested that attack on both the methyl and α-methylene group was occurring. The significance of these two mechanisms in the degradation of n-alkanes by this organism was not evident from the data presented. Analyses of fluids from cultures grown on 1-alkenes indicated the presence of 1,2-diols, as well as ω-unsaturated fatty acids, of the same chain length as the substrate. Alcohols present were all unsaturated. Saponifiable and nonsaponifiable material obtained from cells contained essentially the same products. The presence of 1,2-diols and ω-unsaturated fatty acids of the same chain length as the substrate from cultures grown on 1-alkenes indicated that both the terminal methyl group and the terminal double bond were being attacked

Morphology of Bacteriophage-Like Particles from Fusobacterium symbiosum

The morphology of bacteriophage-like particles from the strict anaerobe Fusobacterium symbiosum is described. Attempts to demonstrate plaque formation on the host strain of F. symbiosum and other related species were unsuccessful

Degradation of Hydrocarbons by Members of the Genus Candida III. Oxidative Intermediates from 1-Hexadecene and 1-Heptadecene by Candida lipolytica

Candida lipolytica (Phaff) was grown in a mineral-salts medium amended with either 1-hexadecene or 1-heptadecene as substrate. Intermediates of the same chain length as the substrate were isolated and identified by various analytical procedures. The following intermediates of 16 and 17 carbon atoms were identified: ω-unsaturated acids, ω-unsaturated primary and secondary alcohols, 1,2-epoxides, 1,2-diols, and 2-hydroxy acids. Based on the chemical structure of these compounds, three oxidative mechanisms are proposed for the degradation of long-chain 1-alkenes by this yeast: (i) methyl-group oxidation, (ii) double-bond oxidation, and (iii) subterminal oxidation

Purification and Properties of Undecyl Acetate Esterase from Pseudomonas cepacia Grown on 2-Tridecanone

Undecyl acetate esterase has been purified from Pseudomonas cepacia grown on the methyl ketone, 2-tridecanone. The K(m) for undecyl acetate was 2.3 × 10(−2) M. Polyacrylamide gel electrophoresis indicated that two esterase bands were being recovered during purification. These bands were separated by preparative polyacrylamide gel electrophoresis. Molecular weights were estimated to be approximately 34,500 by several methods. Molecular sieve polyacrylamide gel electrophoresis indicated that the two esterases had the same molecular weight but different charge, which is indicative of isoenzymes

Oxidation of n-Tetradecane and 1-Tetradecene by Fungi

Cunninghamella blakesleeana (minus strain) and a Penicillium species were grown in a mineral-salts medium containing either n-tetradecane or 1-tetradecene as substrate, and ether extracts of the mycelial mats were analyzed for oxidation products. Extracts from Cunninghamella revealed tetradecanoic acid and 13-tetradecenoic acid from the oxidation of n-tetradecane and 1-tetradecene, respectively, thereby indicating that these hydrocarbons were subject to methyl group oxidation. In contrast to Cunninghamella, the Penicillium oxidized the two substrates by subterminal attacks on methylene rather than methyl groups. This was evidenced by tentative identifications of the following alcohols and ketones from oxidation of the hydrocarbons: tetradecan-2-ol, dodecan-1-ol, tetradecan-2-one, and tetradecan-4-one from n-tetradecane, and tetradecen-4-ol, 13-tetradecen-4-ol, tetradecen-3-ol, 13-tetradecen-4-one, and tetradecen-3-one from 1-tetradecene. A pathway for hydrocarbon oxidation is proposed for subterminal oxidation at the methylene alpha to the methyl group

Immunolatex localization by scanning electron microscopy of intestinal bacteria from cockroaches.

An immunolatex reagent was developed from antiserum to Fusobacterium varium, an obligate anaerobe isolated from the colon of the cockroach, Periplaneta americana L. A new technique that enabled the preparation of a highly efficient immunolatex conjugate was used to localize the bacterium with scanning electron microscopy, in situ, in the mixed gut contents

Assimilation of Alkanes and Alkenes by Fungi

A group of filamentous fungi were assayed for their ability to utilize a series of n-alkanes and 1-alkenes as the sole source of carbon. Although strains of Cunninghamella exhibited profuse growth on most of the hydrocarbons tested, the majority of fungi tested were able to produce definite growth on one or more of the compounds. The hydrocarbons with a 14-carbon chain length appeared to be more consistently utilized than any other. Strains of Aspergillus appeared to differ in their capacity to utilize individual members of the hydrocarbon series. Thin-layer chromatographic analyses of ether extracts from C. blakesleeana grown on n-tetradecane and 1-tetradecene were similar and revealed the presence of a monocarboxylic acid, a primary alcohol, and a secondary alcohol