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A G MARR

Publications and source records attributed to A G MARR.

At least 19 recordsLinked to original sources
PubMed1965

LOCATION OF CHLOROPHYLL IN RHODOSPIRILLUM RUBRUM.

Holt, Stanley C. (University of California, Davis), and Allen G. Marr. Location of chlorophyll in Rhodospirillum rubrum. J. Bacteriol. 89:1402-1412. 1965.-If cells of Rhodospirillum rubrum are broken by sonic and ballistic disruption, the chlorophyll is not found in discrete cytoplasmic structures, but is located in a more extensive structure of the cell, the intracytoplasmic membrane. Direct electron microscopy of sonically disrupted cells of R. rubrum and stereo-electron microscopy of osmotically shocked cells reveal the presence of a tubular network of internal membranes originating from the periphery of the cell.

Cell Biology↗
PubMed1965

ISOLATION AND PURIFICATION OF THE INTRACYTOPLASMIC MEMBRANES OF RHODOSPIRILLUM RUBRUM.

Holt, Stanley C. (University of California, Davis), and Allen G. Marr. Isolation and purification of the intracytoplasmic membranes of Rhodospirillum rubrum. J. Bacteriol. 89:1413-1420. 1965.-When Rhodospirillum rubrum was disrupted in a French pressure cell, two colored bands were observed after density-gradient centrifugation: an upper band containing chromatophores and a lower band containing cell envelopes. A similar analysis of the pigmented components after disruption by osmotic shock revealed the presence of a third band intermediate between the upper and lower bands. Brief sonic treatment of the contents of this intermediate band produced typical chromatophores. The results establish that chromatophores are produced by fragmentation of the intracytoplasmic membrane.

Cell Membrane↗
PubMed1965

EFFECT OF LIGHT INTENSITY ON THE FORMATION OF INTRACYTOPLASMIC MEMBRANE IN RHODOSPIRILLUM RUBRUM.

Holt, Stanley C. (University of California, Davis), and Allen G. Marr. Effect of light intensity on the formation of intracytoplasmic membrane in Rhodospirillum rubrum. J. Bacteriol. 89:1421-1429. 1965.-Cells of Rhodospirillum rubrum grown at low light intensity were found to contain much more internal membrane than cells grown at high light intensity. Highly purified membranes (chromatophores) from cells grown at low to moderate light intensity had a constant content of chlorophyll. Thus, the regulation of the chlorophyll content of the cell depends upon the formation of greater or lesser amounts of membrane which has a constant concentration of chlorophyll.

Chlorophyll↗
PubMed1964

EFFECT OF THE TEMPERATURE OF GROWTH OF ESCHERICHIA COLI ON THE FORMATION OF BETA-GALACTOSIDASE.

Marr, Allen G. (University of California, Davis), John L. Ingraham, and Craig L. Squires. Effect of the temperature of growth of Escherichia coli on the formation of beta-galactosidase. J. Bacteriol. 87:356-362. 1964.-The synthesis of beta-galactosidase was measured during exponential growth of Escherichia coli in a succinate-minimal medium over a temperature range of 10 to 43 C for the following: (i) a constitutive strain, and (ii) an inducible cryptic strain, induced maximally with isopropyl-thio-beta-d-galactopyranoside (IPTG), or induced submaximally with IPTG. The differential rates of synthesis of beta-galactosidase were identical for the constitutive strain and for the fully induced strain; the rates were constant from 20 to 43 C, and decreased progressively with a decrease in temperature below 20 C. Thus, in the absence of specific repression, the ability of E. coli to produce beta-galactosidase decreases at low temperature. The differential rate of the submaximally induced culture was minimal between 20 and 30 C, and increased progressively with temperature both above 30 C and below 20 C. That the repressor concentration is maximal at 20 C was established by measuring the rate of induced synthesis of beta-galactosidase as a function of the concentration of IPTG; the relative concentrations of repressor were 1.00:3.28:0.25 at 40, 20, and 10 C, respectively. After an abrupt change in temperature, the differential rate of a submaximally induced culture changed gradually to the rate of the steady state, which is in agreement with the proposal that the effect of temperature is on the concentration of repressor and not on the equilibrium between repressor and its site of action. The effect of temperature on catabolic repression was determined by comparing the differential rate of synthesis of beta-galactosidase by a constitutive strain grown in succinate-minimal medium with the rate in glucose-minimal medium at various temperatures; the ratio of the rates in the two media decreased progressively and approached 2.0 as the temperature of growth was increased.

Cold Temperature↗
PubMed1962

Location of enzymes in Azotobacteragilis.

Robrish, Stanley A. (University of California, Davis) and Allen G. Marr. Location of enzymes in Azotobacter agilis. J. Bacteriol. 83: 158-168. 1962.-If the cells of Azotobacter agilis are disrupted by osmotic shock, respiratory enzymes and the compounds characteristic of cell wall and cytoplasmic membrane are recovered almost completely in large particles. The large particles obtained by osmotic shock were found by electron microscopy to consist of cell wall, cell membrane, and an internal membrane appearing as either vesicles or tubules in section. These envelopes are free of all the soluble cytoplasmic material and are essentially free of ribosomes. Small particles obtained by osmotic shock are ribosomes; small particles obtained by sonic oscillation consist of both ribosomes and amorphous material, presumably fragments of the envelope.

Azotobacter↗
PubMed1962

Damage and derepression in Escherichia coli resulting from growth at low temperatures.

Ng, Henry (University of California, Davis), John L. Ingraham, and Allen G. Marr. Damage and derepression in Escherichia coli resulting from growth at low temperatures. J. Bacteriol. 84:331-339. 1962.-Exponentially growing cultures of Escherichia coli ML30 were subjected to abrupt changes in temperature. If the change in temperature was made within the range of temperature in which the temperature characteristic, mu, is constant, exponential growth resumed immediately at a rate characteristic of the new temperature. But, if the shifts were made to or from a temperature below the range of constant mu, the initial growth rate was intermediate to the rates normal for the initial and final temperatures. The results indicate that growth at low temperature alters or damages the cell in a way that reduces the growth rate. A period of growth at higher temperature is required to correct the damage. Release from glucose repression of the induction of beta-galactosidase occurs at a temperature coincident with low-temperature damage. Derepression may be the damage that results from growth at low temperature.

Cold Temperature↗
PubMed1961

Polyol dehydrogenases of Azotobacter agilis.

Marcus, Leon (University of California, Davis), and Allen G. Marr. Polyol dehydrogenases of Azotobacter agilis. J. Bacteriol. 82:224-232. 1961.-Two soluble diphosphopyridine-linked polyol dehydrogenases are formed by Azotobacter agilis (A. vinelandii). The first, d-mannitol dehydrogenase is induced by d-mannitol and all of the pentitols except l-arabitol. Ribitol is an excellent inducer of mannitol dehydrogenase although it is not metabolized, nor does the enzyme act upon it. This allows study of the gratuitous induction of mannitol dehydrogenase. Of the polyols tested, mannitol dehydrogenase oxidizes d-mannitol, d-arabitol, d-rhamnitol, and perseitol, demonstrating its requirement for substrates bearing the d-manno configuration. The corresponding 2-ketoses, d-fructose, d-xylulose, and presumably d-rhamnulose, and perseulose are reduced. The second enzyme, l-iditol dehydrogenase is induced only by polyols containing the d-xylo configuration, i.e., sorbitol and xylitol. l-Iditol dehydrogenase oxidizes d-xylo polyols seven times faster than it does d-ribo polyols. Substrates oxidized include l-iditol, sorbitol, xylitol, and ribitol. The corresponding 2-ketoses, l-sorbose, d-fructose, d-xylulose, and d-ribulose, are reduced. The two polyol dehydrogenases have been separated and purified by chromatography on a modified cellulose ion exchanger.

Azotobacter↗