PubMed Health⌕ Search

Biomedical subjects

D S Hoare

Publications and source records attributed to D S Hoare.

At least 19 recordsLinked to original sources
PubMed1979

(1-14C) acetate assimilation by obligate methylotrophs, Pseudomonas methanica and Methylosinus trichosporium.

The oxidation of one carbon compounds (methane, methanol, formaldehyde, formate) and primary alcohols (ethanol, propanol, butanol) supported the assimilation of [1-14C]acetate by cell suspensions of type I obligate methylotroph, Pseudomonas methanica, Texas strain, and type II obligate methylotroph, Methylosinus trichosporium, strain PG. The amount of oxygen consumed and substrate oxidized correlated with the amount of [1-14C]acetate assimilated during oxidation of C-1 compounds and primary alcohols. Oxidation of methanol, formaldehyde, and primary alcohols in extracts of Pseudomonas methanica, Texas strain, and Methylosinus trichosporium, strain PG, was catalyzed by a phenazine methosulfate linked, ammonium ion dependent methanol dehydrogenase. The oxidation of aldehydes was catalyzed by a phenazine methosulfate linked, ammonium ion independent aldehyde dehydrogenase. Formate was oxidized by a NAD+ linked formate dehydrogenase.

Acetates↗
PubMed1977

(14C)acetate assimilation by a type I obligate methylotroph, Methylococcus capsulatus.

Methanol and formate oxidation supported the assimilation of [14C]acetate by cell suspensions of Methylococcus capsulatus; oxidation of other primary alcohols, except ethanol, did not. The extent of [1-14C]acetate assimilation supported by methanol oxidation was decreased in the presence of primary alcohols, except ethanol. Potassium cyanide (0.33 mM) completely inhibited the oxidation of formate and its stimulation of [1-14C]acetate assimilation. The amount of [1-14C]acetate assimilation supported by methanol oxidation was significantly inhibited by cyanide.

Acetates↗
PubMed1973

Physiological studies of methane- and methanol-oxidizing bacteria: immunological comparison of a primary alcohol dehydrogenase from Methylococcus capsulatus and Pseudomonas sp. M27.

A primary alcohol dehydrogenase was purified from cell extracts of two apparently unrelated microorganisms, namely, Pseudomonas sp. M27 and Methylococcus capsulatus. Rabbit antiserum prepared against the purified enzyme from M. capsulatus revealed distinctive antigenic determinants by quantitative and gel precipitin reactions. Rabbit antiserum to M27 enzyme detected both distinctive and shared antigenic determinants. Certain methane- and methanol-oxidizing bacteria were grouped on the basis of serological cross-reacting enzyme specificities.

Alcohol Oxidoreductases↗
PubMed1972

New obligate methylotroph.

A new and unique obligate methylotroph was isolated from enrichment cultures with methanol as the sole source of carbon and energy. The organism grows only on methanol and methylamine and not on methane. It does not have a complex intracellular membrane system. (14)C-acetate was assimilated by growing cultures and cell suspensions but was incorporated into only a limited number of cell constituents. (14)C-acetate incorporation was strictly dependent on the oxidation of methanol or methylamine as a source of energy. Extracts had relatively low levels of enzymes of the tricarboxylic acid cycle, and alpha-ketoglutarate dehydrogenase was not detected. Comparisons were made with a facultative methylotroph isolated from the same enrichment cultures. The new obligate methylotroph contained hexose phosphate synthetase, a key enzyme in the ribose phosphate cycle of methyl metabolism.

Acetates↗
PubMed1972

Physiological studies of methane- and methanol-oxidizing bacteria: comparison of a primary alcohol dehydrogenase from Methylococcus capsulatus (Texas strain) and Pseudomonas species M27.

A primary alcohol dehydrogenase has been purified from Methylococcus capsulatus (Texas strain). The purified enzyme catalyzes the oxidation of methanol and formaldehyde to formate; other primary alcohols are oxidized to their corresponding aldehydes. Ammonium ions are required for enzyme activity. The enzyme has a molecular weight of 120,000 daltons and consists of two 62,000 molecular-weight subunits which dissociate at acidic pH. The enzyme is similar to an alcohol dehydrogenase enzyme isolated from Pseudomonas sp. M27.

Alcohol Oxidoreductases↗
PubMed1971

Pteridines produced by Methylococcus capsulatus. Isolation and identification of a neopterin 2':3'-phosphate.

Three pteridines have been isolated from the methane- or methanol-oxidizing bacterium Methylococcus capsulatus. Two of these are known compounds, 2-amino-6-carboxy-4-hydroxypteridine and 2-amino-4-hydroxy-6-methylpteridine. The third is shown by degradative and synthetic experiments to be l-threo-neopterin 2':3'-phosphate. Labelling experiments show that both the pteridine moiety and phosphate residue are derived from a single GTP molecule. The possible metabolic significance of these compounds in methanol oxidation is discussed.

Bacteria↗
PubMed1971

Heterotrophic growth of blue-gren algae in dim light.

A unicellular blue-green alga, Agmenellum quadruplicatum, and a filamentous blue-green alga, Lyngbya lagerheimíi, were grown heterotrophically in dim light with glucose as major source of carbon and possibly energy. The dim-light conditions did not support autotrophic growth. The two blue-green algae appeared to have the same metabolic block, namely an incomplete tricarboxylic acid cycle, as has been found in other obligately phototrophic blue-green algae. Under dim-light conditions, glucose made a greater contribution to cell constituents (amino acids) of A. quadruplicatum and L. lagerheimii than under high-light conditions.

Acetates↗
PubMed1971

Physiological studies of methane and methanol-oxidizing bacteria: oxidation of C-1 compounds by Methylococcus capsulatus.

Methylococcus capsulatus grows only on methane or methanol as its sole source of carbon and energy. Some amino acids serve as nitrogen sources and are converted to keto acids which accumulate in the culture medium. Cell suspensions oxidize methane, methanol, formaldehyde, and formate to carbon dioxide. Other primary alcohols are oxidized only to the corresponding aldehydes. Oxidation of formate by cell suspensions is more sensitive to inhibition by cyanide than is the oxidation of other one carbon compounds. This is due to the cyanide sensitivity of a soluble nicotinamide adenine dinucleotide-specific formate dehydrogenase. Oxidation of formaldehyde and methanol is catalyzed by a nonspecific primary alcohol dehydrogenase which is activated by ammonium ions and is independent of pyridine nucleotides. Some comparisons are made with a strain of Pseudomonas methanica.

Alcohol Oxidoreductases↗
PubMed1971

Denitrification with methanol: a selective enrichment for Hyphomicrobium species.

Hyphomicrobium species were enriched in media with methanol as sole carbon source under conditions supporting denitrification. Pure cultures of Hyphomicrobium species were isolated which denitrified vigorously with methanol. Hyphomicrobium B522, isolated by aerobic enrichment, was adapted to anaerobic growth and denitrification. Hyphomicrobium B522 and a new isolate were surveyed for anaerobic growth and denitrification on a number of simple organic compounds. Cell suspensions were tested for denitrifying activity. Nitrogen production from nitrate and nitrite and carbon dioxide production from methanol were stoichiometric.

Anaerobiosis↗
PubMed1969

New facultative Thiobacillus and a reevaluation of the heterotrophic potential of Thiobacillus novellus.

A new facultatively autotrophic Thiobacillus has been isolated in pure culture. The general physiological characteristics of the organism are described together with a redescription of Thiobacillus novellus. The new isolate differs from T. novellus in its ability to grow heterotrophically at faster rates and on a greater range of organic compounds. It can be transferred readily between autotrophic and heterotrophic conditions. It can grow anaerobically by nitrate respiration on a number of organic compounds, but not on thiosulfate. Some problems in the nomenclature and taxonomy of the thiobacilli are discussed with reference to the new isolate.

Cell-Free System↗
PubMed1969

Hydrogen metabolism by Rhodomicrobium vannielii.

Under appropriate cultural conditions, cell suspensions of Rhodomicrobium vannielii effect two distinct photoreactions involving molecular hydrogen: (i) the photoreduction of carbon dioxide, and (ii) the photoproduction of hydrogen.

Bacteria↗