INTRODUCTION ............................................................ A NOTE ONTERMINOLOGY. ENERGY TRANSDUCTIONS IN MITOCHONDRIA ......................... Theories of Energy Conservation ............................................ Chemical coupling hnpothesis ............................................. Conformational coupling .................................................. Chemiosmotic hypothesis ................................................ Point and Counterpoint ..................................................... Permeability of the mitochondrial membrane to protons .................... Vectorial organization of respiratory catalysts ............................. Proton extrusion and the generation of a membrane potential ............... The coupling device: ATPase and ion translocation ........................ Uncoupling and proton conduction ........................................ Fluorescent molecules as probes of the energized state ...................... Metabolite Transport by Mitochondria ...................................... Accumulation of calcium .................................................. Accumulation of potassium ............................................... Transport of phosphate and substrate anions .............................. Summary: Energy Transductions in Mitochondria ........................... ENERGY TRANSFORMATIONS IN BACTERIAL MEMBRANES............ Structural Basis ........................................................... Oxidative Phosphorylation .................................................. General features of respiration and phosphorylation ........................ Coupling factors: the role of ATPase ...................................... Nature of phosphorylating particles from bacterial membranes ............. Coupling of respiration to phosphorylation ................................. Photosynthetic Phosphorylation ............................................. Coupling of Metabolism to Transport ........................................ Transport systems and carriers ........................................... Group translocation ...................................................... Kinetic approach to energy coupling ....................................... Coupling of transport to the respiratory chain in membrane vesicles. Ion gradients and energy coupling ......................................... Role of the Membrane in Motility ............................................ Bacteriocins and the Energized State ........................................ SUMMARY AND PROSPECT .............................................. LITERATURE CITED ....................................................... 172 174 175 175 176 176 177 180 180 180 181 182 183 184 185 185 186 188 189 190 191 193 193 195 196 199 200 201 201 202 205 207 210 214 215 216 216

Conservation and transformation of energy by bacterial membranes.

Hegeman, G. D. (University of California, Berkeley). Synthesis of the enzymes of the mandelate pathway by Pseudomonas putida. I. Synthesis of enzymes by the wild type. J. Bacteriol. 91:1140–1154. 1966.—The control of synthesis of the five enzymes responsible for the conversion of d(−)-mandelate to benzoate by Pseudomonas putida was investigated. The first three compounds occurring in the pathway, d(−)-mandelate, l(+)-mandelate, and benzoylformate, are equipotent inducers of all five enzymes. A nonmetabolizable inducer, phenoxyacetate, also induces synthesis of these enzymes; but, unlike the metabolizable inducer-substrates, it does not elicit synthesis of enzymes that mediate steps in the pathway beyond benzoate. Under conditions of semigratuity, dl-mandelate elicits immediate synthesis at a steady rate of the first two enzymes of the pathway, but two enzymes which act below the level of benzoate are synthesized only after a considerable lag. Succinate and asparagine do not significantly repress the synthesis of the enzymes responsible for mandelate oxidation.

Synthesis of the Enzymes of the Mandelate Pathway by Pseudomonas putida I. Synthesis of Enzymes by the Wild Type

https://science.sciencemag.org/content/sci/161/3846/1093.full.pdf

Microbial degradation of aromatic compounds.

1 Two strains of Pseudomonas were grown with phenol and used to prepare cell extracts that metabolized catechol with the transient formation of 2-hydroxymuconic semialdehyde 2 One of these preparations catalysed the conversion of 1mol of catechol into 1mol each of formate and 4-hydroxy-2-oxovalerate 3 A method for the determination of 4-hydroxy-2-oxovalerate is described, together with some properties of this compound and its 2,4-dinitrophenylhydrazone 4 Another partially purified cell extract converted 1mol of 4-hydroxy-2-oxovalerate, formed enzymically from catechol, into 1mol each of acetaldehyde and pyruvate This aldolase had a pH optimum of about 88, was stimulated by Mg(2+) ions and appeared to attack only one enantiomer of synthetic 4-hydroxy-2-oxovalerate

/pdf/the-bacterial-degradation-of-catechol-24i4crucx8.pdf

The bacterial degradation of catechol

Tabak, Henry H. (Robert A. Taft Sanitary Engineering Center, Cincinnati, Ohio), Cecil W. Chambers, and Paul W. Kabler. Microbial metabolism of aromatic carbon compounds. I. Decomposition of phenolic compounds and aromatic hydrocarbons by phenol-adapted bacteria. J. Bacteriol. 87:910-919. 1964.-Bacteria from soil and related environments were selected or adapted to metabolize phenol, hydroxy phenols, nitrophenols, chlorophenols, methylphenols, alkylphenols, and arylphenols when cultured in mineral salts media with the specific substrate as the sole source of carbon. A phenol-adapted culture (substrate-induced enzyme synthesis proven) was challenged in respirometric tests with 104 related compounds; probable significant oxidative activity occurred with 65. Dihydric phenols were generally oxidized; trihydric phenols were not. Cresols and dimethylphenols were oxidized; adding a chloro group increased resistance. Benzoic and hydroxybenzoic acids were oxidized; sulfonated, methoxylated, nitro, and chlorobenzoic acids were not; m-toluic acid was utilized but not the o- and p-isomers. Benzaldehyde and p-hydroxybenzaldehyde were oxidized. In general, nitro- and chloro-substituted compounds and the benzenes were difficult to oxidize.

Microbial metabolism of aromatic compounds. i. decomposition of phenolic compounds and aromatic hydrocarbons by phenol-adapted bacteria.

SUMMARY: Adaptive patterns for a vibrio indicate that the oxidation of phenylalanine to homogentisic acid by this organism may proceed by two different pathways, one through phenylpyruvic and phenylacetic acids and the other through tyrosine and p-hydroxyphenylpyruvic acid. That the former pathway is used is confirmed by the isolation from metabolism fluids of the phenylhydrazone of phenylpyruvic acid. The vibrio does not appear to oxidize the side chains of phenylpropionic and phenylacetic acids before ring fission. The influence of cell suspension density on rates of oxidation of various highly polar compounds which may penetrate slowly into the cells has been studied.

The bacterial oxidation of aromatic compounds.

The bacterial oxidation of aromatic compounds closely related in chemical structure may proceed by different pathways. Thus, while the main features of the breakdown of mandelic acid are established, those of phenylacetate are not, except insofar as it is known to follow a different route (Stanier, 1950). The divergencies may possibly indicate a difference in the mode of ring fission; and since it is established that mandelic acid and certain other aromatic compounds give rise to ,-ketoadipic acid (Kilby, 1948, 1951; Stanier, 1950), we have investigated the production of keto acids in phenylacetate metabolism. At the same time we have attempted to determine whether the reactions of the tricarboxylic acid cycle play a part in these oxidations, and whether there is any evidence under favorable conditions for an abridged cycle as postulated by Barron, Ardao, and Hearon (1950) for Corynebacterium creatinovorans and termed by them the \"dicarboxylic acid cycle\". Pyruvic acid accumulates in aerated cultures of Aerobacter aerogenes growing on glucose or various dicarboxylic acids only when its rate of production exceeds the demands of logarithmic growth, while shortly after cell division ceases its presence may no longer be detected (Dagley et al., 1951). Since conditions in a growing or fully grown culture may not favor detection of metabolic intermediates, we have followed keto acid production by nonproliferating suspensions aerated in media from which the source of nitrogen has been omitted. Under such conditions the concentration of keto acids in the medium rises initially, attains a maximum, and then declines eventually to zero when the rate of decomposition exceeds the rate of formation. In studies of keto acid production, therefore, it is essential to conduct kinetic investigations over a period of time defined by the position of the concentration maximlum.

The bacterial oxidation of phenylacetic acid.

Isolated cell envelopes of a marine bacterium, M.B.3, have been prepared which possess a nonspecific, cation-activated nucleotidase. The cell envelope comprises approximately 35% (dry weight) of the whole cell and contains protein, 60.2%; lipids, 20.7%; hexose, 3.4%; and ribonucleic acid, 4.6%. No deoxyribonucleic acid could be detected in the preparations. The nucleotidase has an essential requirement for Mg 2+ ; maximum activation at p H 8.0 occurs at a divalent cation concentration of approximately 80 mm. At a Mg 2+ to adenosine 5′-triphosphate (ATP) ratio of 2:1, the enzyme was further stimulated by monovalent cations Na + , K + , NH 4 + , and Li + . Maximum activity was found at a monovalent ion concentration of approximately 0.3 m. The envelope preparation liberated inorganic orthophosphate (P i ) from ATP, adenosine 5′-diphosphate (ADP), and adenosine 5′-monophosphate (AMP) at similar rates. Thin-layer and ion-exchange chromatography show that when AMP, ADP, and ATP were utilized as substrate, approximately 1, 2, and 3 moles of P i , respectively, were produced per mole of adenosine. P i was also liberated from the 5′-triphosphates of guanosine, uridine, and cytidine. The enzyme preparation did not attack p -nitrophenyl phosphate, β-glycerophosphate, or inorganic pyrophosphate. Sulfhydryl inhibitors p -chloromercuribenzoate, N -ethyl maleimide, and iodoacetate had little effect upon the nucleotidase activity. Ca 2+ and ethylenediaminetetraacetic acid caused complete inhibition of the system, whereas ouabain had no effect upon the enzyme activity. The concentrations of Na + (0.3 m) and Mg 2+ ions (60 to 80 mm) required for maximum ATP-hydrolyzing activity were similar to those concentrations necessary for maintenance of cell integrity and for the prevention of cell lysis. Images

Cation-activated nucleotidase in cell envelopes of a marine bacterium.

Isolated cell envelopes of a marine bacterium, M.B.3, have been prepared which possess a nonspecific, cation-activated nucleotidase. The cell envelope comprises approximately 35% (dry weight) of the whole cell and contains protein, 60.2%; lipids, 20.7%; hexose, 3.4%; and ribonucleic acid, 4.6%. No deoxyribonucleic acid could be detected in the preparations. The nucleotidase has an essential requirement for Mg2+; maximum activation at pH 8.0 occurs at a divalent cation concentration of approximately 80 mm. At a Mg2+ to adenosine 5′-triphosphate (ATP) ratio of 2:1, the enzyme was further stimulated by monovalent cations Na+, K+, NH4+, and Li+. Maximum activity was found at a monovalent ion concentration of approximately 0.3 m. The envelope preparation liberated inorganic orthophosphate (Pi) from ATP, adenosine 5′-diphosphate (ADP), and adenosine 5′-monophosphate (AMP) at similar rates. Thin-layer and ion-exchange chromatography show that when AMP, ADP, and ATP were utilized as substrate, approximately 1, 2, and 3 moles of Pi, respectively, were produced per mole of adenosine. Pi was also liberated from the 5′-triphosphates of guanosine, uridine, and cytidine. The enzyme preparation did not attack p-nitrophenyl phosphate, β-glycerophosphate, or inorganic pyrophosphate. Sulfhydryl inhibitors p-chloromercuribenzoate, N-ethyl maleimide, and iodoacetate had little effect upon the nucleotidase activity. Ca2+ and ethylenediaminetetraacetic acid caused complete inhibition of the system, whereas ouabain had no effect upon the enzyme activity. The concentrations of Na+ (0.3 m) and Mg2+ ions (60 to 80 mm) required for maximum ATP-hydrolyzing activity were similar to those concentrations necessary for maintenance of cell integrity and for the prevention of cell lysis.

F. C. Happold

Papers

The bacterial oxidation of aromatic compounds.

The bacterial oxidation of phenylacetic acid.

Cation-activated nucleotidase in cell envelopes of a marine bacterium.

Cation-activated Nucleotidase inCell Envelopes ofa Marine Bacterium1