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PubMed1965

AMINO ACID ISOMERIZATION IN THE PRODUCTION OF L-PHENYLALANINE FROM D-PHENYLALANINE BY BACTERIA.

To establish an advantageous method for the production of l-amino acids, microbial isomerization of d- and dl-amino acids to l-amino acids was studied. Screening experiments on a number of microorganisms showed that cell suspensions of Pseudomonas fluorescens and P. miyamizu were capable of isomerizing d- and dl-phenylalanines to l-phenylalanine. Various conditions suitable for isomerization by these organisms were investigated. Cells grown in a medium containing d-phenylalanine showed highest isomerization activity, and almost completely converted d- or dl-phenylalanine into l-phenylalanine within 24 to 48 hr of incubation. Enzymatic studies on this isomerizing system suggested that the isomerization of d- or dl-phenylalanine is not catalyzed by a single enzyme, "amino acid isomerase," but the conversion proceeds by a two step system as follows: d-pheylalanine is oxidized to phenylpyruvic acid by d-amino acid oxidase, and the acid is converted to l-phenylalanine by transamination or reductive amination.

Amino Acids↗
PubMed1963

EFFECTS OF COPPER ON BACILLUS SUBTILIS.

Weed, Lawrence L. (Western Reserve University, Cleveland, Ohio). Effects of copper on Bacillus subtilis. J. Bacteriol. 85:1003-1010. 1963.-Variants have been isolated from liquid cultures of Bacillus subtilis 168 after exposure to copper. The variations manifested are in terms of loss of capacity to be transformed from tryptophan auxotrophy to prototrophy as shown by variant NTCu, and in terms of colony size and altered base composition of the deoxyribonucleic acid as shown by variant SC-22. In addition to the data on altered morphology and chemical composition of the variants, detailed studies on the reversion of one of the variants to B. subtilis are presented.

Adenine↗
PubMed1963

ROLE OF FERREDOXIN IN THE METABOLISM OF MOLECULAR HYDROGEN.

Valentine, R. C. (University of Illinois, Urbana) and R. S. Wolfe. Role of ferredoxin in the metabolism of molecular hydrogen. J. Bacteriol. 85:1114-1120. 1963.-The metabolism of molecular hydrogen by Clostridium pasteurianum, Micrococcus lactilyticus (Veillonella alcalescens), and several other anaerobic bacteria was studied. Oxidation of hydrogen, using several electron-accepting substrates including triphosphopyridine nucleotide, uric acid, xanthine, nitrite, and hydroxylamine, required ferredoxin in conjunction with hydrogenase. Evolution of hydrogen from pyruvate, alpha-ketoglutarate, hypoxanthine, and dithionite was mediated by ferredoxin. On the basis of these findings, a unitary hypothesis for biological hydrogen evolution is proposed in which ferredoxin plays a key role.

Chromatography↗
PubMed1963

NUTRITION OF LEPTOSPIRA POMONA. III. CALCIUM, MAGNESIUM, AND POTASSIUM REQUIREMENTS.

Johnson, R. C. (Fort Detrick, Frederick, Md.) and N. D. Gary. Nutrition of Leptospira pomona. III. Calcium, magnesium, and potassium requirements. J. Bacteriol. 85:983-985. 1963.-The cation requirements for Leptospira pomona Wickard were investigated employing a basal medium prepared with 10% deionized rabbit serum and containing 10(-3)m NH(4)Cl, 5 mug/ml thiamine, and 0.01 m Na(2)HPO(4) buffer (pH 7.4). Rabbit serum was deionized by passage through a column of Amberlite IRC-50 resin. This basal medium did not support growth when either Ca(++) or Mg(++) was added to it. However, when both Ca(++) (3 x 10(-5)m) and Mg(++) (5 x 10(-6)m) were present, growth was obtained. Although an absolute requirement for K(+) could not be demonstrated, an increase in the amount of growth did occur if K(+) (5 x 10(-5)m) was incorporated in addition to Ca(++) and Mg(++). When adequate concentrations of Ca(++) and K(+) were present with a limiting concentration of Mg(++) (less than 5 x 10(-7)m), filamentous cells were observed.

Animals↗
PubMed1964

OXAMIC TRANSCARBAMYLASE OF STREPTOCOCCUS ALLANTOICUS.

Bojanowski, R. (University of Illinois, Urbana), Elizabeth Gaudy, R. C. Valentine, and R. S. Wolfe. Oxamic transcarbamylase of Streptococcus allantoicus. J. Bacteriol. 87:75-80. 1964.-An improved colorimetric assay for carbamyl oxamate, which allows the precise measurement of the activity of oxamic transcarbamylase, has been developed. Activity is maximum over the pH range from 8.3 to 8.7. A cation requirement is satisfied by 2.5 x 10(-3)m Mg(++) or Mn(++). The equilibrium constant for the phosphorolysis of carbamyl oxamic acid is 1.6, corresponding to a negative free energy change of -285 cal per mole.

Adenosine Triphosphate↗
PubMed1964

UNIDENTIFIED GROWTH FACTOR FOR A LACTIC ACID BACTERIUM.

Weinman, Donald E. (University of Georgia, Athens), George K. Morris, and William L. Williams. Unidentified growth factor for a lactic acid bacterium. J. Bacteriol. 87:263-269. 1964.-Lactobacillus bulgaricus Georgia strain required an unidentified growth factor, named Georgia bulgaricus factor (GBF), when grown on a semisynthetic basal medium. Aqueous extracts of torula yeast and beef liver were the best sources of GBF. Adenine, ribonucleic acid (RNA), alkaline digests of RNA, and Mg(++) also stimulated growth, but to a considerably lesser extent than liver and yeast extracts. Several purines, pyrimidines, and related compounds also promoted growth responses in individual experiments, but not consistently. Intact deoxynucleic acid (DNA), deoxyadenylic acid (dAMP), and deoxyguanylic acid (dGMP) inhibited growth. The DNA and dAMP inhibitions were fully reversed by crude sources of GBF, while dGMP inhibition was only partially reversed. RNA reversed DNA inhibition to a small extent. GBF was stable to heat at pH 2.5 to 11 and to prolonged light exposure. It was destroyed by heating at pH 1.0. The GBF activity moved as a single component in paper chromatography. It was firmly adsorbed on charcoal and poorly soluble in organic solvents. A concentrate, 28 times more potent than liver extract, was prepared by prolonged paper chromatography. All known growth factors and biological compounds readily available were assayed for GBF activity, none of which gave a response similar to the crude extracts. Final proof that a new growth factor exists must await definite identification of the active compounds.

Adenine↗
PubMed1964

NUTRITIONAL CONTROL OF MORPHOGENESIS IN ARTHROBACTER CRYSTALLOPIETES.

Ensign, Jerald C. (University of Illinois, Urbana), and R. S. Wolfe. Nutritional control of morphogenesis in Arthrobacter crystallopoietes. J. Bacteriol. 87:924-932. 1964.-Arthrobacter crystallopoietes exhibits the cyclic, morphological variation which is a characteristic of this genus. A simple chemically defined medium was developed in which this organism is restricted to growth and division entirely in the coccoid form. Addition singly to this medium of l-arginine, l-phenylalanine, l-asparagine, l-lysine, succinate, malate, fumarate, lactate, or butyrate results in the formation of the rod-shaped stage. A large number of other compounds either increase, have no effect on, or inhibit growth without inducing morphological change in the organisms.

Amino Acids↗
PubMed1964

LEAF-NODULE SYMBIOSIS. I. ENDOPHYTE OF PSYCHOTRIA BACTERIOPHILA.

Centifanto, Ysolina M. (University of Florida, Gainesville), and Warren S. Silver. Leafnodule symbiosis. I. Endophyte of Psychotria bacteriophila. J. Bacteriol. 88:776-781. 1964.-The leaf-nodule endophyte of Psychotria bacteriophila has been repeatedly isolated in pure culture from germinating seedlings and young leaves on a nitrogen-free mineral agar. Its morphological, serological, and cultural characteristics place it within the Klebsiella-Aerobacter group. The endophyte has been provisionally named Klebsiella rubiacearum. Pure cultures fix N(2) under anaerobic conditions with good efficiency (4.54 mug of N fixed/mg of glucose utilized in 3 days). Nitrogen fixation by pure cultures is intimately related to pyruvate and hydrogen metabolism.

Carbohydrate Metabolism↗
PubMed1964

CAPSULAR POLYSACCHARIDE OF AZOTOBACTER AGILIS.

Cohen, Gary H. (University of Vermont, Burlington), and Donald B. Johnstone. Capsular polysaccharide of Azotobacter agilis. J. Bacteriol. 88:1695-1699. 1964.-Capsular polysaccharide from Azotobacter agilis strain 132 was recovered from washed cells by alkaline digestion. The polysaccharide was purified by centrifugation, repeated alcohol precipitation, Sevag deproteinization, and treatment with ribonuclease and charcoal-cellulose. Methods of isolation and purification appeared to provide a polymer showing no evidence of heterogeneity when examined by chemical and physical methods. Colorimetric, paper chromatographic, and enzymatic analyses on both intact and acid-hydrolyzed polysaccharide indicated that the polymer contained galactose and rhamnose at a molar ratio of approximately 1.0:0.7. A sialic acid-like component was also present in the polysaccharide. The study shows significant differences in the chemical composition of the extra-cellular polysaccharide of A. agilis and that of A. vinelandii. This adds further biochemical evidence for the right of these species to independent status.

Azotobacter↗
PubMed1965

COLORIMETRIC DETERMINATION OF COLOR OF AERIAL MYCELIUM OF STREPTOMYCETES.

Lyons, Allister J., Jr. (Northern Regional Research Laboratory, Peoria, Ill.) and Thomas G. Pridham. Colorimetric determination of color of aerial mycelium of streptomycetes. J. Bacteriol. 89:159-169. 1965.-For some time, streptomycete taxonomists have been seeking to describe more accurately the colors of aerial mycelium. Some of the descriptive systems involve many different color names and groups. Others combine many colors into a few groups. All the systems and methods leave much to be desired. To obtain an accurate description, a colorimeter with a reflectance attachment was used to examine streptomycete aerial mycelium of 37 strains, representing all of the major aerial mycelium color groups. Each color was characterized by three values: dominant wavelength in millimicrons, and purity and brightness in percentages. All colors of aerial mycelium were of low purity (< 25%). Most of the dominant wavelengths were in the yellow to yellow-green bands of the spectrum. Most of the color tabs matched visually with the streptomycete strains had purities of a higher value than those of the cultures. The reflectance instrument seems to allow an objective description, and its use may help to clarify the color problem with streptomycetes. It is concluded that present color descriptions are inadequate and that the significance of color in speciation requires critical examination.

Color↗
PubMed1965

AMINO ACID UTILIZATION BY ALCALIGENES VISCOLACTIS FOR GROWTH AND SLIME PRODUCTION.

Punch, J. D. (University of Minnesota, St. Paul), J. C. Olson, Jr., and J. V. Scaletti. Amino acid utilization by Alcaligenes viscolactis for growth and slime production. J. Bacteriol. 89:1521-1525. 1965.-The ability of Alcaligenes viscolactis to utilize amino acids in a basal salts solution (K(2)HPO(4), KH(2)PO(4), MgSO(4), MnSO(4), FeSO(4), NaCl) was studied. Of 27 amino acids, only l-asparagine, l-glutamic acid, l-aspartic acid, l-glutamine, l-proline, and l-tyrosine supported growth sufficient to give a viscous supernatant solution. l-Proline and l-tyrosine, singly or combined, fulfilled the carbon, nitrogen, and energy requirements for growth and slime production. None of eight inorganic nitrogenous compounds supported growth with lactose as the carbon source. The addition of l-asparagine, l-aspartic acid, or l-glutamine to l-tyrosine or l-proline, singly or combined, did not increase growth or slime production, indicating no nutritional interactions among these amino acids. Neither lactose nor glucose was found to be required or utilized by A. viscolactis in a medium containing basal salts, l-proline, l-tyrosine, and lactose or glucose. This was established by the fact that total carbohydrate and total reducing activity remained constant during growth and slime production.

Alcaligenes↗
PubMed1965

CONTROL OF PYRIDOXINE BIOSYNTHESIS IN ESCHERICHIA COLI.

Dempsey, Walter B. (University of Florida, Gainesville). Control of pyridoxine biosynthesis in Escherichia coli J. Bacteriol. 90:431-437. 1965.-The total pyridoxine in a culture of exponentially growing Escherichia coli was 3.6 x 10(-10) moles per mg of dry cells. One-fourth of this total was present in the medium, and was at least 90% pyridoxal 5'-phosphate. Both pyridoxol and pyridoxal, when present initially at 6 x 10(-7)m, substituted entirely for de novo synthesis of pyridoxine. The other four forms of the pyridoxine group were ineffective at this concentration. Pyridoxine biosynthesis in exponentially growing cultures of E. coli was immediately stopped by adding pyridoxol to the medium to a final concentration of 4 x 10(-7)m. Amino acid auxotrophs of E. coli suspended in minimal medium without the required amino acid produced extracellular pyridoxine for several hours at an average rate of 1.3 x 10(-10) moles per hr per mg of dry cells. The rate of production of extracellular pyridoxine by a threonine-starved threonine auxotroph was not altered by growing the culture before starvation in media containing 6 x 10(-5)m pyridoxol. The extracellular form of pyridoxine produced in these starvations required hydrolysis to be detected in the bioassay used in these measurements. The total findings suggest that pyridoxine biosynthesis is controlled by a rapidly acting mechanism but not by repression.

Amino Acids↗