bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of
Methanobacterium mobilis
, sp. n., Isolated from the Bovine Rumen
Authors: Paynter M. J. B. , Hungate R. E.
Published: January 2020

A methanogenic bacterium, present in bovine rumen contents at concentrations of approximately 2 × 10
8
cells per ml, has been isolated in pure culture. The organism is a strictly anaerobic, weakly motile, nonsporeforming, gram-negative rod (0.7 μ × 1.5 to 2.0 μ) with rounded ends. There is a single polar flagellum. The organism grows at temperatures between 30 and 45 C, with an optimum at 40 C, and at
p
H values between 5.9 and 7.7, with optimal growth between
p
H 6.1 and 6.9. Of the 17 substrates tested, only formate and H
2
plus CO
2
supported growth. An unidentified, heat-stable factor(s) was required by the organism. The factor, which was not one of the common ones, was present in rumen fluid, mixed rumen bacteria, and yeast extract. On the basis of colony morphology, Gram reaction, and motility, the organism is classified as a new species of methanogenic bacterium, and the name
Methanobacterium mobilis
sp. n. is proposed.
Bordetella pertussis-induced Alteration of the Normal Hyperglycemic Response of Mice to 3′,5′-Adenosine Phosphate
Authors: Cronholm Lois S. , Fishel Charles W.
Published: January 2020

Blockade of the adrenergic receptors or the injection ofBordetella pertussisvaccine prevented the normal hyperglycemic response of CFW mice to exogenous cyclic 3′,5′-adenosine phosphate (3′,5′-AMP). The cyclic nucleotide was also ineffective in offsetting the histamine hypersensitivity of the β-adrenergically blocked and the pertussis-sensitized groups. These observations suggest that the autonomic malfunction occurs at a point(s) subsequent to release of 3′,5′-AMP. Neither the hyperglycemic effect of epinephrine or 3′,5′-AMP, or both, nor the histamine sensitivity of pertussis-pretreated animals was influenced by the subcutaneous administration of theophylline.
Streptococcus faecium
var.
casseliflavus
, nov. var
Authors: Mundt J. Orvin , Graham Wanda F.
Published: January 2020

Streptococcus faecium
var.
casseliflavus
is a gram-positive, spherical cell. The cells occur chiefly as pairs within chains and elongate to ogive-shaped cells during growth. Growth is good on 5% bile salts-agar and in broth at 10 C, and in broth adjusted to
p
H 9.6 or containing 6.5% NaCl, but many strains fail to grow at 45 C. Litmus is reduced rapidly prior to formation of an acid curd. Few strains release ammonia from arginine or serine. The organism is not proteolytic and does not produce H
2
S or acetylmethylcarbinol, reduce nitrate, decarboxylate tyrosine, or produce slime on sucrose-agar. Most strains survive heating to 60 C for 30 min. It produces gray colonies on potassium tellurite agar, reduces 2,3,5-triphenyltetrazolium-HCl to a pink color, and ferments cellobiose, dextrin, maltose, mannose, and sorbitol, thus resembling
S. faecalis
. Like
S. faecium
, it produces peroxidase but not catalase on heated blood media, dissimilates malate, and ferments arabinose, melibiose, and salicin, but not melezitose. Like both species, it ferments dextrose, galactose, lactose, mannitol, sucrose, trehalose, and citrate. Properties peculiar to the variant include the high
p
H limiting initiation and termination of growth; the fermentation of α-methyl-
d
-glucoside, raffinose, and xylose; motility; and growth without blue button formation in ethyl violet broth. The water-soluble, pale lemon-yellow pigment is released into the aqueous phase only after the cell envelope is altered by fat solvents. The bacterium thrives as an epiphyte on plants.
Antibiotic, Detergent, and Complement Sensitivity ofSalmonella typhiAfter Ethylenediaminetetraacetic Acid Treatment
Authors: Muschel Louis H. , Gustafson Linda
Published: January 2020

Antimicrobial substances, including antibiotics such as polymyxin and novobiocin, detergents, and complement, all of which are known or presumed to have an effect upon membrane permeability, showed greater potency against ethylenediaminetetraacetic acid (EDTA)-treatedSalmonella typhithan against untreated cells of that organism. The differential effect was particularly marked with the complement system when serum antibody was limiting. EDTA-treated cells were also more susceptible to penicillin and bacitracin. On the other hand, such treatment did not affect the potency againstS. typhiof mitomycin C, the aminoglycosides, chloramphenicol, and chlortetracycline, nor did it affect the permeability ofS. typhito these compounds.
Recall of Immunity in Mice Vaccinated with
Salmonella enteritidis
or
Salmonella typhimurium
Authors: Collins Frank M.
Published: January 2020

Mice were immunized with living
Salmonella enteritidis
or
S. typhimurium
and then were reinfected 8, 30, 60, and 150 days later with streptomycin-resistant strains of
S. enteritidis, S. typhimurium
, or a mixture of the two organisms. The level of resistance at the time of challenge and the rate at which resistance was recalled in late convalescence was determined by daily liver and spleen counts of the challenge population. An immediately effective specific antibacterial immunity was maintained only while the vaccinating strain could still be detected in the liver and spleen. Reinfection of vaccine-free mice with the homologous organism caused a rapid recall of antibacterial immunity (within 3 days), but the response to the heterologous organism was much slower (5 to 8 days). Simultaneous injection of both pathogens into the vaccinated mice resulted in liver and spleen growth curves which resembled those obtained when the two organisms were administered separately. The implications of these growth studies in the development of specific cellular immunity to
Salmonella
infections are discussed.
Phospholipid Alterations During Growth of
Escherichia coli
Authors: Cronan John E.
Published: January 2020

As cultures of
Escherichia coli
progressed from the exponential growth phase to the stationary growth phase, the phospholipid composition of the cell was altered. Unsaturated fatty acids were converted to cyclopropane fatty acids, and phosphatidyl glycerol appears to have been converted to cardiolipin. With dual isotope label experiments, the kinetics of synthesis of cyclopropane fatty acid for each of the phospholipids was examined in vivo. The amount of cyclopropane fatty acid per phospholipid molecule began to increase in phosphatidyl ethanolamine at a cell density below the density at which this increase was observed in phosphatidyl glycerol or cardiolipin. The rate of this increase in phosphatidyl glycerol or in cardiolipin was faster than the rate of increase in phosphatidyl ethanolamine. After a few hours of stationary-phase growth, all the phospholipids were equally rich in cyclopropane fatty acids. It is suggested that the phospholipid alterations observed are a mechanism to protect against phospholipid degradation during stationary phase growth. Cyclopropane fatty acid synthetase activity was assayed in cultures at various stages of growth. Cultures from all growth stages examined had the same specific activity in crude extracts.
Sequential Replication of the Chromosome of
Bacillus licheniformis
Authors: Tyeryar F. J. , Lawton W. D. , MacQuillan A. M.
Published: January 2020

A sequential replication map of the chromosome of
Bacillus licheniformis
was constructed by employing the method of gene-frequency analysis presented by Yoshikawa and Sueoka. Our analysis of 11 genetic markers was based on the hypothesis that the chromosome initiated replication at a fixed origin and proceeded in a linear fashion to the terminus. The proposed locations of markers were validated by cotransformation and cotransduction analyses. Bacteriophage SP-15 cotransduced markers that failed to show linkage by transformation.
Glucose Catabolism of
Erysipelothrix rhusiopathiae
Authors: Robertson D. C. , McCullough W. G.
Published: January 2020

The pathways of glucose catabolism in
Erysipelothrix rhusiopathiae
have been identified by the radiorespirometric technique. The radiorespirometric data showed that 96% of the glucose catabolism was via the Embden-Meyerhof-Parnas pathway with the remaining 4% dissimilated by the hexose monophosphate pathway. The products of the anaerobic dissimilation of glucose were determined. Lactic acid was the major product; ethyl alcohol, acetic acid, formic acid, and carbon dioxide were formed in smaller amounts.
Fatty Acid Composition of the Complex Lipids ofStaphylococcus aureusDuring the Formation of the Membrane-bound Electron Transport System
Authors: White David C. , Frerman Frank E.
Published: January 2020

InStaphylococcus aureus, 64 fatty acids could be separated by gas-liquid chromatography. The fatty acids consisted of normal, iso, and anteiso saturated fatty acids of from 10 to 21 carbon atoms. Of the total fatty acids, 2 to 4% were normal, iso, and anteiso monoenoic fatty acids. Positional isomers of the normal monoenoic fatty acids could be detected. The fatty acids could be extracted, leaving 1 to 2% of the total fatty acids in the residue. The proportions of the fatty acids in the residue and the total lipids differed significantly. The lipid extract contained less than 0.12% free fatty acid. Between 5 and 10% of the lipid fatty acids were associated with neutral lipids. The majority of the fatty acids were associated with the complex lipids: mono- and diglucosyl diglyceride, phosphatidyl glycerol, lysyl phosphatidyl glycerol, and cardiolipin. The proportions of the fatty acids changed markedly between bacteria grown anaerobically (no membrane-bound electron transport system) and those grown aerobically (containing a functional electron transport system). In each of the complex lipids, the proportions of the fatty acids, as well as the magnitude and direction of change in the molar quantity of the fatty acids per bacterium, changed dramatically between these growth conditions. Since the glucosyl diglycerides and phospholipids were formed from the same pool of diglyceride intermediates, the marked differences in fatty acids indicate that acyl transferase activities must be an important part of complex lipid metabolism inS. aureus.
Polar and Antipolar Mutants in the Tryptophan Operon of
Salmonella typhimurium
Authors: Balbinder Elias , Blume Arthur J. , Weber Anne , Tamaki Hideo
Published: January 2020

Polar mutations in
trpA
, the first structural gene of the tryptophan operon of
Salmonella typhimurium
, have an uncoordinate effect on the expression of the distal genes, with
trpB
, the second gene, being more drastically affected than the last three. A number of these polar mutant strains grow very poorly on anthranilic acid-supplemented minimal medium. By selecting for more rapid growth in the presence of anthranilic acid, secondary mutant clones showing a correction of the polar effect were isolated. A few of these were analyzed and shown to contain deletions of various segments of the
trpA
gene. Ten randomly isolated deletion mutants missing various segments of the
trp
operon were analyzed for possible pleiotropic effects. Five of them showed a pleiotropic effect of some sort and five did not. Of those showing pleiotropic effects, one had lost the promotor-like elements necessary to initiate expression of the operon, three showed possible antipolar effects, and one showed both polar and antipolar effects simultaneously.
Analysis of Polar and Nonpolar Tryptophan Mutants by Derepression Kinetics
Authors: Blume Arthur J. , Weber Anne , Balbinder Elias
Published: January 2020

A comparison of the rates of synthesis of the tryptophan biosynthetic enzymes of
Salmonella typhimurium
under derepression showed that the genes of the
trp
operon can be expressed in a coordinate fashion in auxotrophs carrying nonpolar mutations. This coordination disappeared in
trpA
polar mutants. The loss of coordination affected only
trpB
, the second gene in the operon, which was always more drastically affected than the three distal genes. Polar mutations in
trpA
, the first gene of the
trp
operon, reduced the rates of synthesis of the tryptophan biosynthetic enzymes under conditions of derepression. When these rates were measured and correlated with the map position of each polar mutation, a polarity gradient of decreasing intensity (moving distally from the operator end of the gene) was obtained. Certain mutations (“unusual mutations”) mapping at the operator distal end of
trpA
, and considered by other workers to correspond to the operator proximal end of
trpB
, were found to be polar. The bearing of our observations on the question of coordinate versus semicoordinate expression of the
trp
genes and the status of the “unusual mutations” is discussed.
Microcyst Germination in
Myxococcus xanthus
Authors: Ramsey W. Scott , Dworkin Martin
Published: January 2020

Germination of glycerol-prepared microcysts of
Myxococcus xanthus
was studied. The sequence of morphological events during germination resembled that of germinating fruiting body-microcysts. The turbidity drop of a culture of germinating microcysts could be described by McCormick's formula derived for germinating
Bacillus
spores. The rate of uptake of labeled glycine and acetate did not change during germination. Temperature, aeration, and
p
H optima for germination were the same as for vegetative cell growth. Germination was induced by protein hydrolysates and the individual amino acids glycine, alanine, valine, aspartic acid, and glutamic acid. A number of organic compounds, including sugars, alcohols, aldehydes, ketones, organic acids, and chelating agents, did not induce germination. The inorganic ions HPO
4
2−
, Mg
++
, Ca
++
, and NH
4
+
induced germination, although ionic strength was not a factor. Microcysts incubated in distilled water at concentrations greater than about 10
9
cells/ml germinated; supernatant fluid from such suspensions (germination factor) induced germination of less concentrated suspensions. The activity of germination factor was resistant to boiling, but was lost on charring and dialysis. Germination of microcysts and growth of vegetative cells was equally sensitive to a variety of metabolic inhibitors, including penicillin and chloramphenicol. Germination was more resistant than vegetative growth to inhibition by antibiotics of the streptomycin family and by actinomycin D.
Regulation and Timing of Deoxyribonucleic Acid Synthesis in Hyphae of
Aspergillus nidulans
Authors: Kessel M. , Rosenberger R. F.
Published: January 2020

Pulse labeling of deoxyribonucleic acid (DNA) and radioautography have been used to study the effect of growth rate on nuclear replication in
Aspergillus nidulans
. When conidia were germinated in media supporting a fast growth rate, the radioactive pulse labeled either all of the nuclei in a cell or none of them. At slower growth rates, hyphae contained both labeled and unlabeled nuclei. Altering the growth rate thus changed nuclear replication from simultaneous to sequential. The time taken to duplicate the DNA in a nucleus, estimated from the ratio of labeled to total nuclei, remained constant at the different doubling times. The distribution of label showed that nuclei in the same hypha spent unequal times in both the postmitotic gap (G1) and the premitotic gap (G2) periods when grown at slow rates. These unequal G1 and G2 periods are considered to cause asynchrony. Once DNA synthesis was out of phase through growth on a poor medium, transferring the hypha to a rich medium did not resynchronize the nuclei. To interpret the data, two initiator mechanisms, one starting DNA synthesis and the other mitosis, are postulated to control nuclear replication in
A. nidulans
.
Tryptophan Synthetic Pathway and Its Regulation in
Chromobacterium violaceum
Authors: Wegman Judith , Crawford Irving P.
Published: January 2020

Extracts of
Chromobacterium violaceum
catalyzed all of the reactions involved in synthesizing tryptophan from chorismic acid. Tryptophan auxotrophs which had lost any of these activities did not produce the characteristic purple pigment, violacein, when grown on a medium in which tryptophan was limiting. Gel filtration of extracts allowed us to estimate molecular weights for the tryptophan enzymes. All of the enzymes appeared to have molecular weights below 100,000. No enzymes were observed to occur in aggregates. The specific activities of the enzymes of the tryptophan pathway did not change when mutants were grown under conditions of limiting or excess tryptophan. The first enzyme in the pathway, anthranilate synthetase, was subject to feedback control by the end product, tryptophan. Tryptophan acted as a noncompetitive inhibitor with respect to glutamine, one of the substrates for anthranilate synthetase, and as a competitive inhibitor of the reaction when chorismate, the other substrate, was varied. The nonlinearity observed in the Lineweaver-Burk plot in the latter case suggests that there may be more than one chorismate-binding site on anthranilate synthetase.
Formic Hydrogenlyase and the Photoassimilation of Formate by a Strain of
Rhodopseudomonas palustris
Authors: Qadri S. M. Hussain , Hoare D. S.
Published: January 2020

A photosynthetic bacterium isolated by enrichment on media containing formate as major source of cell carbon was identified as a strain of
Rhodopseudomonas palustris
. It grew on a wide range of simple organic compounds including alcohols, fatty acids, and hydroxyacids, on a chemically defined medium with biotin and
p
-aminobenzoic acid as essential growth factors. The organism grew on formate or photoautotrophically with molecular hydrogen or thiosulfate only in the presence of yeast extract. Ability to photoassimilate formate could be shown only in organisms grown in the presence of formate. The organism contained an inducible formic hydrogenlyase consisting of a soluble formic dehydrogenase, a particulate hydrogenase, and one or more intermediate, but as yet unidentified, electron carriers. The formic hydrogenlyase could be reconstituted from a particulate hydrogenase and a partially purified soluble formic dehydrogenase. Some properties of the formic dehydrogenase and hydrogenase have been compared with that of the formic hydrogenlyase system.
Derepression of β-Galactosidase Synthesis in
Escherichia coli
K-12 by
p
-Fluorophenylalanine
Authors: Kang Soosang , Rockey Paul , Markovitz Alvin
Published: January 2020

p
-Fluorophenylalanine (FPA) derepresses β-galactosidase synthesis at 35 C but not at 25 C in
Escherichia coli
K-12, strain MC132 (
lac
I1,2), a strain with a temperature-sensitive
lac
repressor. In contrast, strain MC130 (
lac
I
+
) is not derepressed by FPA at 35 C. Temperature-shift experiments with strain MC132 in the presence of FPA and other reagents (isopropyl-1-thio-β-
d
-galactoside or chloramphenicol) are consistent with the following mechanism. FPA is incorporated into the genetically altered
lac
repressor at all temperatures. This further alteration due to incorporation of analogue makes the
lac
repressor protein inactive at 35 C but active at 25 C. Once an active tertiary structure is formed at 25 C, it is stable at 35 C. However, the inactive tertiary structure of the FPA-containing repressor can assume an active tertiary structure when the temperature is shifted from 35 to 25 C. In the discussion of the results, “inactive tertiary structure” is equated with “monomers” and “active tertiary structure” with oligomers.
Disc Immuno-Immobilization Method for Simultaneous Typing and Isolation ofSalmonellaFlagellar Phases
Authors: Mohit Behzad
Published: January 2020

Salmonellaorganisms of an unknown serotype are inoculated in the center of a motility agar plate, and paper discs impregnated with antiflagellar antisera are placed in the periphery of the plate. The plate is incubated at room temperature overnight. During this time, the bacteria spread in a widening circle toward the discs, while the antiserum from each disc, in turn, diffuses centrifugally. When the motile organisms encounter an antiserum reacting with their flagella, they are immobilized. A semicircular line of immobilization is noted around the reactive antiserum disc. Eleven differentSalmonellaisolates were typed in duplicate by a standard method and by the immuno-immobilization method. Results obtained by the two methods were essentially identical. Simultaneously, single phases were isolated from the zone between the immobilization line and its antiserum disc. Isolates from this region were of the phase not immobilized by the antiserum disc. The dried discs, prepared in tris(hydroxymethyl)aminomethane buffer and stored at 4 C, were stable for at least 5 months. The method can be used for the study of relatedness of surface antigens of motile, growing bacteria, thus circumventing the need for solubilization of these antigens. The results obtained can be interpreted in a similar fashion to the “identity”-“nonidentity” lines of the Ochterlony double-diffusion technique for soluble antigens.
Interactions Between Macrophages of Guinea Pigs and Salmonellae I. Fate of
Salmonella typhimurium
Within Macrophages of Normal Guinea Pigs
Authors: Hsu H. S. , Radcliffe Anna S.
Published: January 2020

A suspended cell culture procedure was described for the cultivation of guinea pig macrophages infected with
Salmonella typhimurium
. The fate of the intracellular bacteria was assessed by quantitative recovery of viable bacteria with 0.5% solution of sodium desoxycholate. Two strains of
S. typhimurium
with different degrees of virulence for mice were compared. There was an initial destruction of intracellular bacteria of both strains; however, the extent of this destruction differed. Approximately 1% of the avirulent bacteria initially phagocytized survived at the end of 4 hr, whereas approximately 8% of the virulent bacteria survived at the end of 3 hr. After this initial killing, the intracellular bacteria began to multiply at a logarithmic rate between 3 and 21 hr after phagocytosis, and then a stationary phase was attained. The rate of this multiplication was comparable for both strains.
Isolation of High-Frequency Recombining Strains from
Escherichia coli
Containing the V Colicinogenic Factor
Authors: Khan Phyllis L.
Published: January 2020

The isolation and characterization of high-frequency recombining strains from different
Escherichia coli
host cells containing either the F factor or the Col V factor are described. The strains (with one exception) formed from three of the V
+
parents showed the same origin and polarity of transfer (
xyl-arg-pro-trp-his-mal
). The Hfr strains formed from the one remaining V
+
and the F
+
host cells showed a greater variety in their points of origin. In addition, several Hfr strains isolated from V
+
parents lost the ability to produce colicin V. F
v
+
segregants of these were isolated, and the F
v
factors appeared to retain their preferential site for Hfr formation, but they lacked other propertes controlled by the Col V factor. Chromosomal integration of episomes and its relation to the fertility of F
+
and V
+
strains are discussed. Production of colicin V appeared to be uninfluenced by the state of the Col V factor within the cell.
Procedure for Identifying Nonsense Mutations
Authors: Berkowitz David , Hushon Judith M. , Whitfield Harvey J. , Roth John , Ames Bruce N.
Published: January 2020

A method has been devised for the rapid identification of nonsense mutations (UAG, UAA, UGA codons) in
Salmonella
. The mutations to be tested are reverted, and the revertants are replica-printed onto lactose plates spread with lawns of tester strains. These tester strains contain F′
lac
episomes with nonsense mutations in the episomal
Z
gene. The revertants are infected with the episome from the tester strain lawn. Because
S. typhimurium
is unable to ferment lactose, only those revertants which have nonsense suppressors are able to grow on lactose. If colonies appear on the lactose plate, it may be concluded that the original strain carries a nonsense mutation, since nonsense suppressors suppress the mutant phenotype.
Crypticity of
Myrothecium verrucaria
Spores to Maltose and Induction of Transport by Maltulose, a Common Maltose Contaminant
Authors: Parrish F. W. , Hahn W. B. , Mandels G. R.
Published: January 2020

Spores of the fungus
Myrothecium verrucaria
are cryptic to maltose and isomaltose. Induction of a transport system can be effected by several sugars whose order of effectiveness is: turanose > maltulose > sucrose >
d
-arabinose,
d
-fructose, nigerose, maltotriulose, kestose > melezitose, raffinose, nystose, and stachyose. The transport system is not specific to maltose and isomaltose, and it is apparently identical to an induced trehalose permease described previously. Induction of the permease is markedly influenced by spore age—older spores being more responsive. Pure maltose is not absorbed by spores. Absorption of commercial reagent-grade maltose is due to permease induction by maltulose as an impurity. Maltulose contamination of maltose was demonstrated by charcoal column chromatography and comparison of its physical, chemical, and permease-inductive properties with those of authentic maltulose. Maltose accumulates temporarily in spores after absorption and then decreases, although no conversion to glucose can be detected. Although spores contain small quantities of maltase, metabolism of maltose may be via some nonhydrolytic pathway.
Isolation and Characterization of Carotenoid Pigments of
Micrococcus roseus
Authors: Ungers Grace E. , Cooney J. J.
Published: January 2020

In addition to canthaxanthin, seven pigment fractions were isolated from
Micrococcus roseus
. They were purified by solvent partitioning and by column and thin-layer chromatography. Visible absorption spectra, chromatographic behavior, and partition coefficients of the pigments and derivatives prepared from the pigments were used in characterizing them. Both α- and β-carotene derivatives were present. The structure of one pigment was suggested as phoenicoxanthin (3-hydroxy-4,4′-diketo-β-carotene). Four other pigments were tentatively characterized as a dihydroxy-3,4-dehydro-α-carotene, a dihydroxy-α-carotene, a diketo-α-carotene, and a polyhydroxy-β-carotene. Two pigments were isolated in trace amounts and could not be characterized. All the pigments studied were isolated as mixtures of
cis-trans
isomers and all except the diketo-α-carotene were isolated as esters from
M. roseus
. Quantitation of the pigments showed that canthaxanthin (4,4′-diketo-β-carotene) represented 85% of the pigment recovered from extracts. Three of the other pigments contributed a significant proportion of the remaining pigments, whereas the other four were present in only small amounts. β-Carotene derivatives comprised 96% and α-carotene derivatives 4% of the pigments recovered from extracts.
Adsorption of Immunoglobulin A onto Oral Bacteria In Vivo
Authors: Brandtzaeg Per , Fjellanger Ivar , Gjeruldsen Sven T.
Published: January 2020

Oral bacteria become coated with immunoglobulin A in human saliva in vivo. This may indicate that the salivary immunoglobulin A possesses antibacterial activity. Some of the immunoglobulin-coated cocci grow in extremely long chains and exhibit synchronous cell division. The long chain phenomenon may result from growth in the presence of salivary antibody specific to antigenic determinants of the bacterial cell walls.
Ultraviolet Microscopy of Purines and Amino Acids in the Vacuole of
Candida albicans
Authors: Balish Edward , Svihla George
Published: January 2020

Ultraviolet (UV) microscopy was used to study the capacity of yeast (ATCC 10231 and 10261) and filamentous (ATCC 10259) strains of
Candida albicans
to accumulate UV-absorbing materials from a medium supplemented with purines, pyrimidines, amino acids, or related compounds as the main nitrogen source. All strains accumulated UV-absorbing compounds when adenine, adenosine, isoguanine, xanthine, or uric acid was supplied as a nitrogen source, but they did not accumulate UV-absorbing compounds when pyrimidines were supplied. The filamentous strain accumulated UV-absorbing material from medium supplemented with hypoxanthine, but the yeast strains did not. In contrast, the yeast strains accumulated more UV-absorbing material than did the filamentous strain when guanine was the nitrogen source. Yeast strain 10231 not only accumulated UV-absorbing material from tyrosine-supplemented medium, but it became filamentous in form as well. Yeast strain 10261 and filamentous strain 10259 did not accumulate detectable amounts of UV-absorbing material, nor was their morphology noticeably affected by the supplement. The two yeast strains accumulated more lipid than the filamentous strain when they were incubated in a nitrogen-deficient medium.
Purification and Properties of
l
-Alanine Dehydrogenase from
Desulfovibrio desulfuricans
Authors: Germano Geno J. , Anderson Kenneth E.
Published: January 2020

The
l
-alanine dehydrogenase from cell-free extracts of
Desulfovibrio desulfuricans
was purified approximately 56-fold. The Michaelis constants for the substrates of the amination reaction and the
p
H optima for the reactions catalyzed by this enzyme closely agree with those reported for other
l
-alanine dehydrogenases. Pyruvate was found to inhibit the amination reaction. The enzyme was absolutely specific for
l
-alanine and nicotinamide adenine dinucleotide. Its sensitivity to para-chloromecuribenzoate suggests that sulfhydryl groups may be necessary for enzymatic activity. These extracts also contained a nicotinamide adenine dinucleotide phosphate-specific glutamic dehydrogenase which was separated from the
l
-alanine dehydrogenase during purification.
Induction of Adenosine Deaminase in
Escherichia coli
Authors: Remy Charles N. , Love Samuel H.
Published: January 2020

Supplementing the salts-glucose medium of
Escherichia coli
with adenine initiates induction of adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4), growth inhibition, and an increased potential for the net deamination of adenine. The extent and duration of these events are proportional to the initial adenine concentration and are dependent upon adenylate pyrophosphorylase and repression of histidine biosynthesis for maximal expression. The conversion of adenine to hypoxanthine, though limited in rate, occurs concurrently with induction and accounts for the progressively decreasing rate of deaminase induction, since hypoxanthine is a relatively ineffective inducer. The subsequent decrease in deaminase activity is due to dilution by continued cell division and by enzyme inactivation which occurs during the late-log and early-stationary phases. The partially purified deaminase is labile to a number of environmental conditions, particularly to phosphate buffers of
p
H 6.8 or less. A disproportionately slow rate of adenine deamination by cells utilizing lactate permits a more prolonged period of induction and, consequently, a greater quantity of enzyme to be synthesized; cell division, but not enzyme inactivation, reduces enzyme concentration. The adenosine deaminases of
Aerobacter aerogenes
and
Salmonella typhimurium
are not inducible.
Purification and Properties of Peroxidase from
Nitrosomonas europaea
Authors: Anderson John R. , Strumeyer David H. , Pramer David
Published: January 2020

Peroxidase from the obligate chemosynthetic bacterium
Nitrosomonas europaea
was purified 1,500-fold, and its properties were examined. The enzyme had a molecular weight of 53,000 and exhibited characteristic absorption maxima at 410, 524, and 558 mμ. The optimal
p
H and temperature were 7.5 and 44 C, respectively. The peroxidase reaction had an energy of activation of 5,850 cal/mole and required a primary substrate (H
2
O
2
) concentration of 7 × 10
−6
m
to proceed at half maximal velocity (
K
m
). Reduced cytochrome,
c,p
-phenylenediamine and pyrogallol acted as hydrogen donors to the purified peroxidase-H
2
O
2
complex. Conditions most suitable for the chemical oxidation of ammonium by H
2
O
2
were determined. The reaction was rapid and produced nitrite but no nitrate. Hydroxylamine was not detected as an intermediate, but it could substitute for ammonium in the system. Neither the rate nor the extent of these reactions was influenced by purified peroxidase, and no evidence was obtained to support a conclusion that the enzyme performs a vital role in the transformation of ammonium to nitrite by
N. europaea
.
Adenosine Triphosphate and Synchronous Mitosis in
Physarum polycephalum
Authors: Chin B. , Bernstein I. A.
Published: January 2020

Synchronous mitoses occur in
Physarum polycephalum
in the absence of cell division. Nucleoside and nucleotide profiles were prepared from synchronously growing
P. polycephalum
at intervals throughout the growth cycle. Comparison of these profiles demonstrates that the pool of adenosine triphosphate decreases from a high level at prophase to a minimum through mitosis and increases again in the postmitotic period. These events appear to coincide with changes in the pools of adenosine diphosphate and adenosine but not with that of adenosine monophosphate. This observed decrease in the pool of adenosine triphosphate during mitosis was confirmed by direct enzymatic assay. These results presumably reflect the energy demands of the cell during mitosis.
Reversal of the Vancomycin Inhibition of Peptidoglycan Synthesis by Cell Walls
Authors: Sinha Rabindra K. , Neuhaus Francis C.
Published: January 2020

Addition of cell walls to the peptidoglycan synthetase-acceptor system containing vancomycin (50 μg/ml) prevented the inhibition by the antibiotic. In addition, the inhibition of incorporation of [
14
C]muramyl-pentapeptide into peptidoglycan in the presence of vancomycin was reversed by the addition of cell walls to the assay mixture at 60 min. Cell walls previously saturated with vancomycin lost their ability to reverse the inhibition by the antibiotic. The inhibition of peptidoglycan synthesis by ristocetin was partially reversed by the addition of cell walls. The initial stage in peptidoglycan synthesis is catalyzed by phospho-
N
-acetyl(NAc)muramyl-pentapeptide translocase (uridine 5′-phosphate) according to the reaction: UDP-NAc-muramyl-pentapeptide + acceptor ⇄ acceptor-phospho-NAc-muramyl-pentapeptide + UMP where acceptor is C
55
-isoprenoid alcohol phosphate. Vancomycin stimulates the transfer of phospho-NAc-muramyl-pentapeptide to the acceptor, and the addition of cell walls to this assay mixture prevented the stimulation of transfer. In addition to the transfer reaction, the enzyme catalyzes the exchange of [
3
H]uridine monophosphate (UMP) with UDP-NAc-muramyl-pentapeptide. The exchange reaction is effectively inhibited by vancomycin. For example, 60 μg of vancomycin per ml inhibited the rate of exchange by 50%. Addition of cell walls restored the exchange of UMP with the UMP moiety of UDP-NAc-muramyl-pentapeptide. Thus, cell walls appeared to have a higher affinity for vancomycin than did either the peptidoglycan synthetase-acceptor system or phospho-NAc-muramyl-pentapeptide translocase. These results provide support for the proposal made by Best and Durham that the effective binding of vancomycin to the cell wall could result in the inhibition of transfer of membrane-associated peptidoglycan chains to the growing wall.
Mutants of
Neurospora crassa
Deficient in Ornithine-δ-Transaminase
Authors: Davis R. H. , Mora J.
Published: January 2020

The
arg-12
s
mutation of
Neurospora
causes a partial block in the ornithine transcarbamylase (OTC) reaction. Strains carrying this mutation will use endogenous ornithine, but not exogenous ornithine, as a precursor of arginine. Certain strains carrying
arg-12
s
may be used for direct selection of variants able to use exogenous ornithine as an arginine precursor. Among eight such derivatives, six lacked the catabolic enzyme ornithine transaminase (OTA). All six mutations were alleles of a single gene, designated
ota
, on linkage group III. No mutation affected arginase, the first enzyme in the catabolic pathway with OTA. Strains carrying
ota
mutations alone are vigorous prototrophs, but, unlike wild-type
Neurospora
, fail to use ornithine efficiently as a sole nitrogen source. The selection method by which
ota
mutants arose suggests that OTA is severely competitive with OTC for exogeneous ornithine.
Regulation of Histidine Catabolism by Succinate in
Pseudomonas putida
Authors: Hug Daniel H. , Roth Dennis , Hunter John
Published: January 2020

The regulation of the histidine-degrading pathway is known to involve induction and repression. Our studies have shown that succinate may control the histidine-degrading pathway by sequential negative feedback inhibition. Succinate inhibited urocanase, and urocanate in turn inhibited histidase. Crude preparations of the two enzymes were made from
Pseudomonas putida
grown on
l
-histidine. Succinate was a competitive inhibitor of urocanase (
K
i
, 1.8 m
m
). Lactate, pyruvate, α-ketoglutarate, and glutamate did not inhibit urocanase. Urocanate inhibited histidase competitively (
K
i
, 0.13 m
m
). A multienzyme system (histidine to glutamate), when incubated with histidine and succinate, exhibited the combined effect. Succinate caused the level of accumulated urocanate to increase and indirectly blocked histidine disappearance. Growth of cells on urocanate as a nitrogen source was inhibited by 1% succinate. Succinate may play a physiological role in the biological regulation of histidine metabolism.
Roles of Arginine and Canavanine in the Synthesis and Repression of Ornithine Transcarbamylase by
Escherichia coli
Authors: Faanes Ronald , Rogers Palmer
Published: January 2020

Conditions were found under which the processes of repression and derepression of ornithine transcarbamylase were separated from the process of enzyme synthesis. After 10 min of arginine deprivation followed by the addition of 2 to 200 μg of
l
-arginine per ml, a number of strains of
Escherichia coli
exhibited a significant burst of ornithine transcarbamylase synthesis which lasted 3 to 4 min before the onset of repression. The rapid increase of enzyme activity was shown to require protein synthesis, and was not due to a slow uptake of arginine or induction of an arginine-inducible ornithine transcarbamylase. The capacity of
E. coli
to synthesize the burst of ornithine transcarbamylase reached a maximum after 10 min of arginine deprivation and then remained constant. The observed increase in enzyme synthesis may reflect the level of unstable messenger ribonucleic acid (RNA) for ornithine transcarbamylase present in the cell at the time protein synthesis was reinitiated. After the addition of arginine in the absence of protein synthesis, the burst of ornithine transcarbamylase decayed with a half-life of about 3 min. The data implied that arginine prevents synthesis of new messenger RNA that can translate this enzyme. Repression of ornithine transcarbamylase by
l
-canavanine (100 to 200 μg/ml) was observed, and no active enzyme was formed in the presence of this analogue. The action of canavanine as a repressor was distinguished from the inhibitory effect of this compound on protein synthesis.
Characteristics of Secretion of Penicillinase, Alkaline Phosphatase, and Nuclease by
Bacillus
Species
Authors: Chesbro William R. , Lampen J. O.
Published: January 2020

The distribution of alkaline phosphatase and nuclease activity between cells and medium was examined in one strain of
Bacillus licheniformis
and four strains of
B. subtilis
. Over 95% of both activities was found in the medium of the
B. licheniformis
culture, but in the
B. subtilis
cultures the amount of enzyme activity found in the medium varied with the strain and the enzyme considered.
B. licheniformis
749 and its penicillinase magnoconstitutive mutant 749/C were grown in continuous culture with phosphorous as the growth-limiting factor, and the kinetics of penicillinase formation and secretion were examined. Nutrient arrest halted secretion (usually after a lag of about 30 min) in both the inducible and constitutive strains. Chloramphenicol did not eliminate secretion, but under certain circumstances reduced its rate. In the inducible strain treated with a low level of inducer, the rate of secretion was more affected by the rate of synthesis than by the level of cell-bound enzyme. During induction, the onset of accretion of cell-bound penicillinase and secretion of the exoenzyme were nearly simultaneous. It seems unlikely that a long-lived, membrane- or cell-bound intermediate is mandatory in the secretion of the three enzymes by
Bacillus
species. In the case of penicillinase secretion, there are at least two different phases. When penicillinase synthesis is proceeding rapidly, the rate of secretion is five to six times greater at equivalent concentrations of membrane-bound penicillinase than it is when penicillinase synthesis is reduced. The data require that any membrane-bound intermediate in the formation of exoenzyme be much shorter-lived in cells with a high rate of synthesis than in cells with a low rate. Either there are two separate routes for the secretion of penicillinase or the characteristics of the process vary substantially between the early stages and the declining phase of induction.
Lytic Effects of Staphylococcal α-Toxin and δ-Hemolysin
Authors: Bernheimer Alan W. , Avigad Lois S. , Grushoff Phyllis
Published: January 2020

Several preparations of staphylococcal α-toxin and δ-lysin were studied in order to compare hemolytic activity with capacity to lyse bacterial protoplasts. δ-Lysin in relatively low concentration lysed protoplasts of
Sarcina lutea
, protoplasts of
Streptococcus faecalis
, and spheroplasts of
Escherichia coli
. Lysis of bacterial protoplasts by preparations of α-toxin appeared to be due to contamination of the preparations with δ-lysin. Data comparing the protoplast-lysing activity of various lytic agents are presented.
Characteristics of the
deo
Operon: Role in Thymine Utilization and Sensitivity to Deoxyribonucleosides
Authors: Lomax Margaret S. , Greenberg G. Robert
Published: January 2020

Inability to grow on deoxyribonucleosides as the sole carbon source is characteristic of
deo
mutants of
Escherichia coli
. Growth of
deoC
mutants, which lack deoxyribose 5-phosphate aldolase, is reversibly inhibited by deoxyribonucleosides through inhibition of respiration. By contrast,
deoB
mutants are not sensitive to deoxyribonucleosides, and deoxyribose 5-phosphate aldolase and thymidine phosphorylase are present at normal levels but are not inducible by thymidine. Organisms with the genotype
deoB
−
thy
−
or
deoC
−
thy
−
are able to grow on low levels of thymine, whereas
deoB
+
thy
−
or
deoC
+
thy
−
strains require high levels of thymine for growth. The
deoB
and
deoC
mutations are transducible with and map on the counterclockwise side of the threonine marker. They are closely linked to
deoA
, a gene determining thymidine phosphorylase. Merodiploids heterozygous for either the
deoB
or
deoC
genes are resistant to deoxyribonucleosides and, in combination with the
thy
mutation, require high levels of thymine for growth. Cultures of
thy
+
deoC
−
mutants are inhibited by thymidine until this compound has been completely degraded and excreted as deoxyribose and thymine, whereupon growth promptly resumes at a normal rate. The inhibition of respiration in
deoC
strains and the induction of thymidine phosphorylase and deoxyribose 5-phosphate aldolase in the wild-type organism are considered to result from the accumulation of deoxyribose 5-phosphate.
Purification of Staphylocidal β-Lysin from Rabbit Serum
Authors: Johnson F. Brent , Donaldson David M.
Published: January 2020

A cationic protein of rabbit serum bactericidal for
Staphylococcus aureus
was purified. The specific activity per unit of protein of the purified staphylocidal preparation was approximately 37,000 times greater than that of the serum from which it was isolated. Similar techniques were used to purify serum β-lysin active against
Bacillus subtilis
approximately 24,000 times. The staphylocidal activity cannot be attributed to the same β-lysin active against
B. subtilis
, lysozyme, or antibody-complement systems. The concentrations of staphylocidal β-lysin in the sera of the five mammalian species studied did not correlate with their β-lysin activities against
B. subtilis
. The two β-lysins are similar in that both were heat-stable, sensitive to trypsin digestion, had molecular weights near 6,000, and were found in higher concentrations in serum than in plasma. Furthermore, similar techniques can be used to absorb and elute both substances in highly purified forms using cellulose asbestos filter pads and ion exchange chromatography on carboxymethyl cellulose. In contrast to the β-lysin against
B. subtilis
, the staphylocidal β-lysin was not released from blood platelets, and it was inactive in the presence of heparin, sodium citrate, sodium oxalate, ethylenediaminetetraacetic acid, acidic phospholipids, and acid
p
H values. A variety of proteins, including those of normal serum, preferentially inhibited the bactericidal activity of staphylocidal β-lysin but not the β-lysin against
B. subtilis
.
Neisseria gonorrhoeae
II. Colonial Variation and Pathogenicity During 35 Months In Vitro
Authors: Kellogg Douglas S. , Cohen Irun R. , Norins Leslie C. , Schroeter Arnold L. , Reising Gilbert
Published: January 2020

During 35 months of selective in vitro cultivation,
Neisseria gonorrhoeae
cells retained their virulence for humans and were shown to be closely related to a particular colonial morphology. Saline-autoagglutinability was the only other characteristic distinguishing virulent from avirulent cells. Human responses to challenge with cells of the different colonial types were studied for their relationships to virulence or avirulence.
Thiamine-induced Formation of the Monopyrrole Moiety of Prodigiosin
Authors: Goldschmidt Millicent C. , Williams Robert P.
Published: January 2020

Thiamine stimulates the production of a red pigment, which is chromatographically and spectrophotometrically identical to prodigiosin, by growing cultures of
Serratia marcescens
mutant 9-3-3. This mutant is blocked in the formation of 2-methyl-3-amylpyrrole (MAP), the monopyrrole moiety of prodigiosin, but accumulates 4-methoxy-2,2,′-bipyrrole-5-carboxaldehyde (MBC) and can couple this compound with MAP to form prodigiosin. Addition of thiamine caused production of MAP, and as little as 0.02 mg of thiamine per ml in a peptone-glycerol medium stimulated production of measurable amounts of prodigiosin. Phosphate salts and another type of peptone decreased the thiamine-induced formation of prodigiosin; yeast extract and glycerol enhanced the formation of this substance. Thiamine also enhanced production of prodigiosin by wild-type strain Nima of
S. marcescens
. The thiamine antagonists, oxythiamine and pyrithiamine, inhibited thiamine-induced production of MAP and of prodigiosin by the mutant strain 9-3-3, formation of prodigiosin by the wild-type strain Nima, and production of MAP by another mutant, strain WF. The pyrimidine moiety of thiamine was only 10% as effective as the vitamin; the thiazole moiety, only 4%; and the two moieties together, 25%. Various other vitamins tested did not stimulate formation of prodigiosin by strain 9-3-3. Thiamine did not stimulate production of prodigiosin by a single-step mutant that showed the same phenotypic block in prodigiosin biosynthesis as strain 9-3-3. This is not surprising since strain 9-3-3 originated as a result of two mutational events. One event may involve thiamine directly, and the other may involve the biosynthesis of MAP. Thiamine is probably involved in the regulation of the biosynthesis of MAP, because the vitamin or inhibitory antagonists must be added during the early phases of growth in order to be effective.