bluuebunny/crossref_metadata_2025 huggingface dataset:
Nature of Penicillin-Induced Growth Inhibition of
Mycoplasma neurolyticum
Authors: Wright D. N.
Published: January 2020

When penicillin was added to cultures of
Mycoplasma neurolyticum
in amounts up to 1,000 units per ml, lag time and generation time were increased and the total population was reduced in proportion to the antibiotic concentration. Although growth suppression by penicillin was complete, the death rate was slow and linear over periods up to 12 days. Growth after induced lag was due to a decay in penicillin activity and was not the result of mutant selection. However, repeated transfer in media which contained increasing concentrations of penicillin resulted in normal growth of
M. neurolyticum
at penicillin levels as high as 1,000 units per ml. Penicillinase did not play a role in recovery from penicillin-induced lag, and the inactive penicillin molecule did not prevent normal growth of
M. neurolyticum
. Removal of penicillin from the medium by washing or penicillinase during the induced lag was immediately followed by normal growth of the organism. These results suggest a reversible antibiotic function for penicillin which prevents multiplication of the organism by means unrelated to cell wall formation.
Adenosine Phosphate Hydrolases in Cell Fractions of
Vitreoscilla
Authors: Burnham J. C. , Hageage G. J.
Published: January 2020

Bound, soluble, and whole-cell fractions of two strains of the gliding bacterium
Vitreoscilla
were found to contain two enzymes capable of hydrolyzing adenosine phosphates: a Mg
++
-activated adenosine triphosphatase with a temperature optimum of 37 C, and a Mg
++
-activated adenosine diphosphatase with a temperature optimum of 55 C. Both enzymes had an optimal
p
H response between 8.5 and 9.5. Maximal activation was achieved at an ionic strength of 0.2 for the adenosine triphosphatase and at 0.3 to 0.4 for the adenosine diphosphatase. Preliminary studies indicated a molecular weight of approximately 50,000 for the adenosine diphosphatase and a molecular weight greater than 60,000 for the adenosine triphosphatase. Comparisons are made with previously reported characteristics of these enzymes in other bacteria, and a hypothesis is offered as to the role these enzymes have in the gliding mechanism.
Some Properties of Heat-Resistant and Heat-Sensitive Strains of
Clostridium perfringens
I. Heat Resistance and Toxigenicity
Authors: Weiss Karl F. , Strong Dorothy H.
Published: January 2020

Heat resistance at 100 C (D-values), sporulating ratios, toxigenicity for mice, and lecithinase activity (as micrograms per milliliter of enzyme, ascertained by the lecithovitellin reaction) were determined for four strains of
Clostridium perfringens
. A definite inverse relationship between thermal resistance and toxigenicity was found. The D-values ranged from 17.6 for the most heat-resistant strain to 0.3 for the strain possessing the least heat resistance, with corresponding lecithinase activities from 25 to 133 μg/ml of enzyme. The sporulating ratios did not differ greatly between the strains. The heat stability of the toxin was greater at 100 C than at 75 C. There was a noticeable difference between the heat stabilities of the toxin in the culture fluids of the heat-sensitive and heat-resistant strains at
p
H 7.0 when the toxic filtrates were held at 100 C. At a holding temperature of 75 C, a similar but lesser difference was observed at
p
H 5.5. Heat resistance and lecithinase activity did not change when a substrain of the least heat-resistant parent strain was obtained through heat selection by a single transfer, or when the most heat-resistant strain was transferred serially 12 times.
Genetic and Biochemical Analysis of the Isoenzymes Concerned in the First Reaction of Aromatic Biosynthesis in
Escherichia coli
Authors: Wallace B. J. , Pittard James
Published: January 2020

Mutant strains of
Escherichia coli
K-12 were isolated possessing mutations which affected the tyrosine-inhibitable 3-deoxy-
d
-arabinoheptulosonic acid-7-phosphate (DAHP) synthetase, the phenylalanine-inhibitable DAHP synthetase, or the tryptophan-repressible DAHP synthetase. The mutations causing the loss of each of these activities have been mapped and are widely separated from each other on the
E. coli
chromosome. Chromatography on diethylaminoethyl cellulose columns allowed the recognition of four peaks of activity.
Inducible System for the Utilization of β-Glucosides in
Escherichia coli
I. Active Transport and Utilization of β-Glucosides
Authors: Schaefler S.
Published: January 2020

Wild-type
Escherichia coli
strains (β-
gl
−
) do not split β-glucosides, but inducible mutants (β-
gl
+
) can be isolated which do so. This inducible system consists of a β-glucoside permease and an aryl β-glucoside splitting enzyme. Both can be induced by aryl and alkyl β-glucosides. In β-
gl
−
and noninduced β-
gl
+
cells, C
14
-labeled thioethyl β-glucoside (TEG) is taken up by a constitutive permease, apparently identical with a glucose permease (GP). This permease has a high affinity for α-methyl glucoside and a low affinity for aryl β-glucosides. No accumulation of TEG occurs in a β-
gl
−
strain lacking glucose permease (GP
−
). In induced β-
gl
+
strains, there appears a second β-glucoside permease with low affinity for α-methyl glucoside and high affinity for aryl β-glucosides. Autoradiography shows that TEG is accumulated by the β-glucoside permease and glucose permease in two different forms (one being identical with TEG, the other probably phosphorylated TEG). In GP
+
β-
gl
+
strains with high GP activity, alkyl β-glucosides induce the enzyme and the β-glucoside permease after a prolonged induction lag, and they competitively inhibit the induction by aryl β-glucosides. The induction lag and competition do not exist in GP
−
β-
gl
+
strains. It is assumed that phosphorylated alkyl and thioalkyl β-glucosides inhibit the induction, and that this inhibition is responsible for the induction lag.
Serological Studies of
Clostridium botulinum
Type E and Related Organisms
Authors: Lynt R. K. , Solomon H. M. , Kautter D. A. , Lilly T.
Published: January 2020

Clostridium botulinum
type E antigens prepared from washed cells by either Formalin treatment or heating at 100 C were used for immunizing rabbits. Agglutination tests showed that high levels of antibody were produced by both types of preparations. Flagellar antigens were highly strain-specific, whereas the somatic antigens were sufficiently similar to produce complete cross-agglutination. One toxigenic strain produced toxigenic and nontoxigenic progeny which were physiologically and antigenically identical in all other respects. Other nontoxigenic strains whose growth, physiological, and morphological characters were identical to type E and strains which had some physiological differences completely cross-agglutinated with type E strains via the somatic antigen. Neither type of antiserum agglutinated other clostridia against which they were tested except for
C. acetobutylicum
. This reaction seems to be due to a nonspecific anamnestic response and does not appear to be related to the immunizing strains. The nontoxigenic strains studied seem to have no greater antigenic differences from type E strains than the type E strains have from each other.
Genetically Alterable Transport of Amethopterin in
Diplococcus pneumoniae
II. Impairment of the System Associated with Various Mutant Genotypes
Authors: Sirotnak Francis M. , Sargent M. Gay , Hutchison Dorris J.
Published: January 2020

Six mutations determining resistance to amethopterin were examined for their effects on the active transport of the drug. In strains bearing each of the mutations and exhibiting resistance levels varying from 10- to 100-fold, transport at limiting concentrations of
H
3
-amethopterin was reduced from 2.5 to 10 times the rate characteristic of the wild type. Kinetic analysis of transport showed an increase in the value for
K
m
of the system in all of the mutants. Values for the wild-type system were 0.9 × 10
−6
m
and for the mutants varied between 2.5 × 10
−6
m
and 9.0 × 10
−6
m
. Values for
V
max
were approximately the same for each system. The mutant transport systems also exhibited a shift in
p
H optimum from near 6.0 (wild-type) to below 5.0. The results were interpreted as an alteration in the binding properties of the permease in the mutant strains.
Magnesium Starvation of
Aerobacter aerogenes
I. Changes in Nucleic Acid Composition
Authors: Kennell David , Kotoulas Angeliki
Published: January 2020

Aerobacter aerogenes
incubated in a medium containing all factors necessary for exponential growth except Mg
++
continued to synthesize nucleic acids and proteins for more than 70 hr, provided the major carbon source was in excess at all times. After 24 hr of Mg
++
starvation, deoxyribonucleic acid content in the culture had increased 10-fold. In contrast, the viable-cell count increased only about threefold during the first few hours and then remained approximately constant for the subsequent 70 hr. After specified intervals of Mg
++
starvation, extracts of the bacteria, or ribonucleic acid (RNA) purified from them, was centrifuged through gradients of sucrose to separate transfer RNA from ribosomal components. After correcting for losses, we obtained the following results. (i) There was a progressive rise in the content of transfer RNA competent to accept amino acids and during starvation it remained completely stable. (ii) In contrast, the contents of normally sedimenting ribosomal RNA and ribosomal subunits (30 and 50
S
) remained approximately constant for more than 24 hr. This did not result from stability of ribosomes made prior to starvation together with an inhibition of synthesis of new particles. Rather, ribosomes were continually breaking down and being replaced by an equivalent number of new ones. (iii) The breakdown of ribosomes appeared to be sequentially ordered; polysomes yielded 70
S
monomers, which then gave 30 and 50
S
particles, and these disintegrated to smaller units and finally to acid-soluble products. (iv) Furthermore, the particles derived from breakdown do not appear to exchange with subparticles on the path of assembly. Thus, ribosome decay was age-dependent and ribosomal RNA molecules had a minimal life expectancy of 90 min; however, some survived much longer.
Magnesium Starvation of
Aerobacter aerogenes
III. Protein Metabolism
Authors: Marchesi Sally L. , Kennell David
Published: January 2020

The metabolism of the ribosomal and soluble protein components of
Aerobacter aerogenes
was examined during its incubation in a Mg
++
-deficient medium. Bacteria were exposed to leucine-
H
3
during the exponential growth period preceding Mg
++
starvation, and extracts were prepared after intervals of starvation and were centrifuged through gradients of sucrose to separate ribosomal from soluble proteins. Ribosomal proteins synthesized during the preceding exponential growth were slowly lost from the ribosomes; after 8 hr of starvation, few, if any, sedimented with ribosomes. Losses of total protein, together with the known rate of ribosome decay during Mg
++
starvation, suggested that these ribosomal proteins are ultimately degraded to acid-soluble products and account for all protein lost by the starving cells. These conclusions were supported by studies of Mg
++
starvation in a uracil-requiring strain of
A. aerogenes
: during uracil starvation a smaller fraction of the proteins synthesized were ribosomal, and the fraction of protein which subsequently decayed during Mg
++
starvation was correspondingly less. During recovery from Mg
++
starvation, proteins, lost from disintegrated ribosomes, were not detectably reutilized into new particles even before their degradation to acid-soluble products was complete. Synthesis of soluble proteins continued for more than 24 hr of starvation at a rate per milliliter close to 45% of the instantaneous rate per milliliter of the exponentially growing bacteria at the time Mg
++
was removed. This value agreed with that found previously for synthetic rates of deoxyribonucleic acid, transfer ribonucleic acid, and ribosomal ribonucleic acid during starvation relative to rates during exponential growth.
Metabolic Changes in Nicotinamide Adenine Dinucleotide in Response to Anthrax Toxin
Authors: Gray Irving , Archer Luis J.
Published: January 2020

Bacillus anthracis
produces a toxin both in vitro and in vivo which, when injected intravenously into rats, brings about the death of the animals accompanied by gross pulmonary edema. Lung tissue removed prior to death showed, in vitro, a 30% reduction in overall oxidative metabolism (Q

o
2

), whereas the nicotinamide adenine dinucleotide (NAD)-independent succinic dehydrogenase remained unaffected. The NAD concentration in the lungs of injected animals was reduced by 50%. Upon addition of NAD, the Q

o
2

of lung tissue from injected animals rose to control values. At 45 min after toxin injection, the serum lactate concentration began to rise, showing about a 3.5-fold increase over controls after 75 min. No changes occurred in the pyruvate concentration. These changes may be explained by increased use of the pyruvate for glycolytic energy production with further loss of NAD. Additional experiments with liver, spleen, kidney, and brain tissues showed that the toxin-induced reduction of Q

o
2

is an effect specific for lung tissue. Brain tissue showed a significant increase in oxidative metabolism upon the addition of the toxin, whereas the other tissues remained unaffected. It is suggested that a principal effect of the toxin is to inhibit, in lung tissue, the regeneration of NAD in the respiratory chain.
Nonchemotactic Mutants of
Escherichia coli
Authors: Armstrong John B. , Adler Julius , Dahl Margaret M.
Published: January 2020

We have isolated 40 mutants of
Escherichia coli
which are nonchemotactic as judged by their failure to swarm on semisolid tryptone plates or to make bands in capillary tubes containing tryptone broth. All the mutants have normal flagella, a fact shown by their shape and reaction with antiflagella serum. All are fully motile under the microscope and all are sensitive to the phage chi. Unlike its parent, one of the mutants, studied in greater detail, failed to show chemotaxis toward oxygen, glucose, serine, threonine, or aspartic acid. The failure to exhibit chemotaxis does not result from a failure to use the chemicals. The swimming of this mutant was shown to be random. The growth rate was normal under several conditions, and the growth requirements were unchanged.
Fine Structure of
Listeria monocytogenes
in Relation to Protoplast Formation
Authors: Ghosh B. K. , Murray R. G. E.
Published: January 2020

Among the eight strains of
Listeria monocytogenes
tested for lysozyme sensitivity, two were resistant to lysozyme but became sensitive after lipase pretreatment. Among the other six, one was very sensitive to lipase and another one was extremely susceptible to lysozyme. Stable protoplasts were formed from the lysozyme-resistant strain (42) by lipase and lysozyme treatment, which completely digested the cell wall. The cell wall (uranyl acetate-lead stained) was of a thick triple-layered profile, with the intermediate layer of low density. Lipase treatment for a short time (60 min) did not cause any alteration in structure, but prolonged treatment (180 min) caused extensive digestion of the plasma membrane and the cell wall, liberating cytoplasmic material. When the cells were treated with either lipase or lysozyme, a small number of protoplasts were extruded through the partly digested or weakened transverse cell wall, leaving an almost intact cell wall ghost. There were small vesicular structures in the interspace between cell wall and plasma membrane. Mesosomes of varied organization were prominent in electron micrographs, both in sections and in negatively stained preparations. These were largely everted during protoplasting in the form of tubules and as small peripheral buds; a few small vesicles also remained as intrusive structures, some of which were very unusual because they appeared to be enclosed by the inner layer of plasma membrane alone. Lysis of the protoplasts by dilution of the sucrose, while maintaining a constant ionic environment, liberated many small vesicular structures and fibrillar nuclear material.
Effect of Temperature on the Intracellular Growth of
Histoplasma capsulatum
Authors: Howard Dexter H.
Published: January 2020

The rate and form of growth of
Histoplasma capsulatum
within histiocytes derived from homothermic and poikilothermic animals, and incubated at 25, 30, and 37 C, are described. The generation time of the fungus in mouse cells incubated at 37 and 25 C was 11 and 24 hr, respectively. Blastospore formation was progressively retarded in cells at 25 C, and this retardation was accompanied by germination of some of the blastospores. The generation time of the fungus in mouse cells incubated at 30 C was the same as it was at 37 C. Germ tube formation was not a prominent feature of intracellular growth at 30 C. The rate of growth of
H. capsulatum
within frog histiocytes at 30 and 25 C was slower than it was in mouse cells at the same temperatures. Some loss of frog histiocytes in cultures incubated at 37 C prevented accurate estimation of the rate of growth of the fungus at this temperature. Growth of
H. capsulatum
in frog histiocytes kept at 25 C was progressively retarded, and the retardation was accompanied by germination of the yeasts. Yeast-phase growth predominated in fish histiocytes incubated at 30 C, whereas germ tubes were formed within such cells incubated at 25 C. Cell survival of fish histiocytes was relatively poor in culture, and no estimates of rate of growth of the fungus within these cells were made.
Factors Enhancing the Host-Cell Penetration of
Toxoplasma gondii
Authors: Norrby Ragnar , Lycke Erik
Published: January 2020

The penetration into HeLa cells of
Toxoplasma gondii
was studied with a cell culture technique. The influence on the rate of penetration and the number of penetrating
Toxoplasma
parasites was tested by use of preparations of disintegrated parasites mixed with test parasites. These preparations were found to contain factors enhancing the penetrating rate of the parasites. This effect was demonstrable by use of untreated parasites as well as parasites lacking active motility owing to a previous exposure to Formalin. The preparations of disintegrated parasites contained, in addition, components inhibitory to the penetration-enhancing factors. These inhibitory components were able to reduce the penetrating capacity of normal
Toxoplasma
parasites, suggesting that the studied enhancing factors may play a role in the natural process of penetration. The efficacy of various techniques for disintegration of
Toxoplasma
parasites was investigated for release of penetration-enhancing factors from
Toxoplasma
parasites. The methods used resemble those used for liberation of lysosomal enzymes. Reduced osmotic pressure was obviously not adequate for release of enhancing factors, whereas the freezing and thawing procedure, sonic treatment, and irradiation produced high yields. It was difficult to evaluate the effect of incubation at acid
p
H on release of enhancing activity, because the penetration-promoting factors seemed unstable on both the acid and the alkaline sides of
p
H 7.6.
Mode of Action of Novobiocin in
Escherichia coli
Authors: Smith David H. , Davis Bernard D.
Published: January 2020

The mechanism of action of novobiocin was studied in various strains of
Escherichia coli
. In all strains tested except mutants of strain ML, the drug immediately and reversibly inhibited cell division, and later slowed cell growth. The previously described impairment of membrane integrity, degradation of ribonucleic acid (RNA), and associated bactericidal effect were found to be peculiar to ML strains. The earliest and greatest effect in all strains was an inhibition of deoxyribonucleic acid (DNA) synthesis; RNA synthesis was inhibited to a lesser extent, and cell wall and protein synthesis were affected later. The inhibition of nucleic acid synthesis was accompanied by an approximately threefold accumulation of all eight nucleoside triphosphates. Since novobiocin does not inhibit nucleoside triphosphate synthesis, degrade DNA, or immediately affect energy metabolism, it must inhibit the synthesis of DNA and RNA by direct action on template-polymerase complexes.
Inversion of Transfer Modes and Sex Factor-Chromosome Interactions in Conjugation in
Escherichia coli
Authors: Low Brooks
Published: January 2020

A study was made of the mating properties of an unusual system of interconvertible donor strains of
Escherichia coli
K-12: Ra-1, Ra-2, and RaF
+
. The Ra-1 and Ra-2 strains are Hfr strains whose origins are widely separated on the chromosome and whose transfer modes proceed in the opposite direction from one another. When Ra-1 cells were mated with females, a small fraction of the donors transferred markers via the Ra-2 mode. This effect was enhanced by preconjugal ultraviolet (UV) treatment of the Ra-1 cells. Among the survivors of UV-treated Ra-1 cells, a few stable Ra-2 cells were found. When Ra-2 cells were used as the donors, some of them were found to mate via the Ra-1 mode, in analogy with the Ra-1 to Ra-2 alteration with inversion of F mentioned above. Related experiments suggested that the inversion occurs by detachment of the F factor from one Hfr origin locus, followed by reassociation of the F factor with the other Hfr origin locus. Both the Ra-1 and Ra-2 strains reverted spontaneously to an F
+
strain, called RaF
+
. Cultures of RaF
+
cells were found to mate primarily according to the Ra-1 and Ra-2 transfer modes, with smaller contributions also coming from transfer modes with origins elsewhere on the chromosome in a way which is similar to the transfer of markers from a normal F
+
strain. The RaF
+
sex factor was found to be wild type, whereas the chromosome was found to carry irregularities (sex factor affinity loci) at the locations of the Ra-1 and Ra-2 origins. Only about 10% of the donor capacity of the RaF
+
strain was due to stable spontaneous Hfr cells in cultures of RaF
+
cells.
Mechanisms of Pathogenesis inListeria monocytogenesInfection II. Characterization of Listeriosis in the CD-1 Mouse and Survey of Biochemical Lesions
Authors: Wilder Martin S. , Sword C. P.
Published: January 2020

Several physiological and biochemical changes which occur in CD-1 pathogen-free mice during the course of infection withListeria monocytogenesstrain A4413 have been examined. Mice injected with 104to 106organisms by the intraperitoneal route displayed a significant depression in weight gain. In contrast, at 24 hr after infection an increment in total liver weight averaging 0.1 g was observed. The ratios of liver to body weight increased throughout the observation period. As the severity of the infection increased, food intake, as well as total liver protein and nitrogen, showed a corresponding decrease, with the diminution being most evident immediately prior to the death of the animals. Blood urea nitrogen remained relatively constant for 24 hr and then increased continuously as the infection progressed to the acute stage. Total liver lipid increased until the death of the animals. At 72 hr postinfection, a significant decrease in oxidative phosphorylation was observed. Xanthine dehydrogenase activity increased, with maximal values obtained 72 hr after infection. Uric acid levels remained constant for 24 hr, diminished at 48 hr, and then increased until the death of the animals. After 24 hr, uricase activity showed a slight increase. This activity returned to within normal ranges at 48 hr and decreased as the infection progressed to the acute stage at 72 hr. The results support the hypothesis that at least a part of the cause of death is a derangement in hepatic purine and carbohydrate metabolism. The data are also consistent with the possibility of changes in iron transport in the infected mice.
Mechanism of Action of Phenethyl Alcohol: Breakdown of the Cellular Permeability Barrier
Authors: Silver Simon , Wendt Louis
Published: January 2020

Phenethyl alcohol (PEA) caused
Escherichia coli
to take up greatly increased amounts of acriflavine, a compound to which healthy growing cells are impermeable. PEA also caused an increased rate of efflux (leakage) of cellular potassium under conditions which do not greatly alter the influx of potassium via the energy-dependent potassium pump. We therefore propose that the primary effect of PEA is a limited breakdown of the cell membrane. The inhibition of deoxyribonucleic acid synthesis and other cellular functions would then be secondary consequences of the alteration in the membrane structure.
Effect of Azasteroids on Gram-Positive Bacteria
Authors: Varricchio Frederick , Doorenbos Norman J. , Stevens Audrey
Published: January 2020

A group of nitrogen-containing steroids closely related in structure was screened for antibacterial activity, by use of
Bacillus subtilis
and
Sarcina lutea
as the test organisms. The most active compounds were cholesterol derivatives containing a tertiary or quaternary nitrogen in, or attached to, the A ring. Similar methyltestosterone or progesterone derivatives were inactive. All of the cholesterol derivatives that inhibited growth were surfactant, and, structurally, they would be classified as cationic detergents. Some of the inactive compounds were surfactant, but, structurally, they would be classified as nonionic detergents. Certain features of the antibacterial activity of one of the active steroids—ND 212 (4-dimethylaminoethyl-4-aza-5-cholesten-3-one methiodide)—were studied. Growth of a culture of
B. subtilis
containing 5 × 10
7
cells per milliliter was inhibited by 1 μg/ml (1.7 × 10
−6
m
) of ND 212. The amount of growth inhibition was directly related to both cell and steroid concentration. Loss of viability was rapid and irreversible. With
B. subtilis
, cell lysis was observed. With
S. lutea
grown in
C
14
-glucose, ND 212 caused release into the media of up to 25% of the cellular radioactivity. Extensive leakage occurred before loss of viability was observed. At bacteriostatic azasteroid concentrations, there was little leakage. ND 212 was readily bound in large amounts to
B. subtilis
cells. Inactive azasteroids were bound poorly.
C
14
-cholestanone was also bound, whereas
C
14
-methyltestosterone and
C
14
-progesterone were not bound in significant amounts. At least 50% of the bound
C
14
-cholestanone was associated with the membrane fraction.
Replacement of a Phosphoenolpyruvate-dependent Phosphotransferase by a Nicotinamide Adenine Dinucleotide-linked Dehydrogenase for the Utilization of Mannitol
Authors: Tanaka Shuji , Lerner Stephen A. , Lin Edmund C. C.
Published: January 2020

Mannitol is dissimilated by
Aerobacter aerogenes
via an inducible pathway initiated by a phosphotransferase system dependent upon phosphoenolpyruvate as the phosphoryl donor. A mutational block in this pathway can be suppressed either at the phenotypic level by induction of
d
-arabitol dehydrogenase, an enzyme fortuitously capable of converting mannitol to fructose, or genotypically by a constitutive mutation in the
d
-arabitol system.
Bacterial Oxidation of 2-Tridecanone to 1-Undecanol
Authors: Forney F. W. , Markovetz A. J. , Kallio R. E.
Published: January 2020

A study of the microbial utilization of long-chain methyl ketones was under-taken. In general, enrichment culture experiments revealed that soil microorganisms capable of utilizing these compounds as growth substrates are ubiquitous. Gram-negative, rod-shaped bacteria were the prominent organisms exhibiting this capability. In particular, a strain of
Pseudomonas
isolated from soil degraded 2-tridecanone into several products that were recovered from cell-free culture fluid. These products were identified by gas-liquid chromatography as 2-tridecanol, 1-undecanol, 1-decanol, and undecanoic acid. A large amount of the substrate was converted to 1-undecanol. This compound was characterized further by classical methods of organic analysis. Unequivocal identification of 1-undecanol has established that some unique mechanism that involves subterminal oxidation must exist to degrade 2-tridecanone. No such mechanism has been reported for the biological degradation of long-chain, aliphatic, methyl ketones. A pathway for utilization of 2-tridecanone was proposed that is consistent with, but not confirmed by, the data presented.
Filamentous Cells of
Escherichia coli
Formed in the Presence of Mitomycin
Authors: Suzuki Hiromi , Pangborn Jack , Kilgore Wendell W.
Published: January 2020

The effects of mitomycin C on cell elongation of
Escherichia coli
B were studied. Filament formation was most marked in cultures treated with a moderate level (1 μg/ml) of the antibiotic, becoming less obvious at higher levels (10 μg/ml). Cells treated with a bacteriostatic concentration (0.1 μg/ml or less) of mitomycin C were also significantly elongated. The filamentous or elongated cells appeared to lack septa, since their spheroplasts were considerably larger than those formed from normal cells. The appearance of empty spheres also indicated some defects in the surfaces of the filamentous cells. Electron micrographs of the filaments revealed a characteristic difference in the arrangement of the nuclei in the filaments formed in the presence of low (0.1 μg/ml) and high (5 μg/ml) concentrations of mitomycin C. The filaments formed by the low level of mitomycin C had normal well-defined nuclear bodies distributed along the long axis, whereas those formed by the elevated level of the antibiotic contained smaller nuclei. The latter were characteristically confined to the center of the cells and did not extend out to the tips of the filaments.
Permanent Stained Agar Preparation of
Mycoplasma
and of L Forms of Bacteria
Authors: Dienes Louis
Published: January 2020

A procedure is described that permits the preparation of permanent stained mounts of
Mycoplasma
and of bacterial L forms grown on the surface of and within agar media. These preparations are especially useful for making representative photographs. The cultures are fixed with Formalin vapor. Thin slices of agar are stained at elevated temperature between 50 and 60 C and at a low
p
H, are dried rapidly, and are mounted in Canada balsam. The results with this staining procedure are illustrated by photographs of various strains of
Mycoplasma
and of bacterial L forms.
Morphology and Reproductive Processes of the L Forms of Bacteria I. Streptococci and Straphylocci
Authors: Dienes Louis
Published: January 2020

The production of L forms from cocci, the conditions necessary for their multiplication, and their morphology have been studied for several years. In each strain studied, only a few organisms produced L forms. Transplants from these grew poorly at first, and growth on agar and in broth became abundant only after long cultivation. Multiplication in the form of small granules was observed only when the organisms were embedded in agar and occasionally in coagulated blood serum. On the surface of hard agar, the organisms increased in size but did not multiply. Abundant growth developed on membrane filters of appropriate size, extending into the filters as branching irregular masses. On gelatin, on most samples of coagulated serum, and on silica gel, the organisms grew to a very large size, and occasionally colonies developed by multiplication of large bodies. This multiplication occurred by irregular enlargement and separation into fragments. Growth in broth and in semisolid agar also occurred by multiplication of large bodies, but, in addition, the development of viable granules was observed inside the large bodies in broth culture. After the L forms began to grow abundantly, their nutritional requirements were simple; they no longer required animal serum. Their ability to multiply and their morphological characteristics depended to a large extent on the physical properties of the environment.
Platinum-Induced Filamentous Growth in
Escherichia coli
Authors: Rosenberg Barnett , Renshaw Earl , Vancamp Loretta , Hartwick John , Drobnik Jaroslav
Published: January 2020

Certain group VIIIB transition metal compounds were found to inhibit cell division in
Escherichia coli
, causing marked filamentous growth. Gram-negative bacilli were the most sensitive to this effect, whereas gram-positive bacilli responded only at near-toxic levels of the metal. None of the cocci tested showed any apparent effect. Cytokinesis (cross-septation) can be initiated by removal or decrease of platinum, but not by treatment with pantoyl lactone, divalent cations, or a temperature of 42 C.
System for the Investigation of the Bacteriophage-directed Synthesis of Diphtherial Toxin
Authors: Matsuda Morihiro , Barksdale Lane
Published: January 2020

Lytic corynebacteriophage βhv64tox+has been characterized, and methods for studying the expression of its tox+gene in nontoxinogenicCorynebacterium diphtheriaestrain C7s(−)tox−described. During one cycle of viral growth there was a 1 million-fold increase in extracellular toxin. Both the conditions of the experiment and the use of purified phage, free from toxin, support the conclusion that all of the toxin was newly formed. This toxin was immunochemically indistinguishable from standard toxin produced by the PW8r(Pdi)tox+strain. Chloramphenicol was found to be an effective agent for synchronizing the initiation of viral growth. Once chloramphenicol was removed, intracellular toxin appeared and continued to increase throughout the latent period. Proflavine, added early in the latent period, blocked phage maturation without similarly affecting yields of toxin. Iron exerted a limited inhibitory effect on final toxin levels attained.
Episome-carried Surface Antigen K88 ofEscherichia coliIII. Morphology
Authors: Stirm Stephan , Ørskov Frits , Ørskov Ida , Birch-Andersen Aksel
Published: January 2020

Two nonfimbriate strains ofEscherichia coliand their K88+counterparts, obtained by episomal transfer of this antigen, were studied with the electron microscope. Specimens were prepared with the spray drop method and were studied after shadow-casting. Under these conditions, the alteration in surface structure, due to the acquisition of K88 antigen, appeared as a fur of fine filaments, distinctly more flexible than fimbriae. Purified K88 antigen was also studied and found to have the same structure.
Postirradiation Cell Division in 5-Fluorouracil-pretreated
Escherichia coli
Authors: Ben-Ishai R. , Zeevi N.
Published: January 2020

The correlation between 5-fluorouracil-induced resistance to ultraviolet (UV) light and the ability of bacterial cells to repair irradiation damage was investigated in various strains of
Escherichia coli
. Preincubation with 5-fluorouracil did not influence the dark-repair mechanism. It affected, however, the UV light-induced damage of cell division in filament-forming strains. It is suggested that the delay in postirradiation macromolecular synthesis of 5-fluorouracil-pretreated bacteria plays a decisive role in the recovery process leading to cross cell wall-forming ability in the damaged strains.
Use of Tetrazolium Salts for Electron Transport Studies in Meningopneumonitis III. Separation and Examination of Large and Small Particles
Authors: Allen Emma G.
Published: January 2020

Purified suspensions of meningopneumonitis can be separated on potassium tartrate gradient into populations which are 80 to 90% large particles and those which are 90% small particles. Examination of the tetrazole reduction of both particle types indicates that the small particle has associated with it all of the enzymatic activity of the preparation; it also has associated with it most of the infectivity as well.
Properties of Yeast Cell Ghosts Obtained by Ribonuclease Action
Authors: Alper R. E. , Dainko J. L. , Schlenk F.
Published: January 2020

Cell ghosts were obtained from
Candida utilis
and
Saccharomyces cerevisiae
by the action of some conformational isomers of pancreatic ribonuclease which passed through the cell wall and penetrated the cell membrane. In the interior, the enzyme caused extensive disorganization of the cellular structure as evidenced by the results of vital staining and electron microscopy. Ribonucleic acid was degraded to fragments that leaked out into the suspending medium. Other cytoplasmic constituents, including the amino acid pool, were released, but most of the cellular protein and deoxyribonucleic acid remained in the ghosts. The lesions in the cytoplasmic membrane were too small to be seen by conventional electron microscopy. The membrane clung to the cell wall even after obliteration of most of the intracellular structure.
Properties of the Glutamate Transport System in
Escherichia coli
Authors: Halpern Yeheskel S. , Even-Shoshan Avivith
Published: January 2020

The properties of the glutamate transport system in two glutamate-utilizing mutants of
Escherichia coli
K-12 were investigated. Growth in the presence of glutamate enhanced the capacity of the bacteria for glutamate uptake. Accumulation of glutamate was found to be an energy-linked highly temperature-dependent process. Nonlinear double reciprocal plots of uptake were obtained in the absence of an exogenous energy source and in the presence of glucose or glycerol. Addition of γ-aminobutyrate, succinate, ketoglutarate, or aspartate accelerated glutamate uptake and brought about “normalization” of its kinetics. Straight-line kinetics of uptake was also observed when succinate served as the source of energy. Under these conditions, aspartate and α-ketoglutarate inhibited glutamate uptake in a noncompetitive fashion, whereas γ-aminobutyrate activated the system. A number of other amino acids were found to act as “noncompetitive” inhibitors.
d
-glutamate and some derivatives of glutamate with an unsubstituted α-carboxylic and α-amino group inhibited
l
-glutamate uptake in a strictly competitive fashion. An allosteric permease model, consistent with all of these findings, is proposed.
Changes in Amino Acid Permeation During Sporulation
Authors: Bernlohr Robert W.
Published: January 2020

Changes in amino acid uptake in
Bacillus licheniformis
and in the amino acid pools of three
Bacillus
species were investigated, by use of cells from different stages of the life cycle.
B. licheniformis
contains catalytic uptake systems for all of the 10 amino acids studied. The apparent maximal velocities of uptake decreased during sporulation but did not fall below the range observed for other microorganisms. In sporulating cells, the apparent affinity constants of the uptake systems for individual amino acids remained about the same as in growing cells, i.e., from 2 × 10
−7
m
to 7 × 10
−6
m
, whereas, in some cases, the apparent maximal velocities decreased significantly. Because the velocity of uptake showed an atypical dependence on substrate concentration, it was postulated that these cells contain two or more uptake systems for each amino acid. Only one of these systems appeared to be operative at a substrate concentration below 10
−6
m
. Working at these low substrate concentrations, catalytic activities producing a net efflux of amino acids were demonstrable in vegetative cells in the presence of chloramphenicol, but these exit systems were lost during sporulation. A pool formed by the addition of radioactive algal hydrolysate will exchange with the external medium in vegetative cells but not in sporulating cells. Glutamic acid and alanine comprise at least 60% of the amino acid pool of
B. licheniformis
A-5,
B. subtilis
23, and
B. cereus
T during all stages of growth and sporulation. The concentrations of the other amino acids in the pool varied extensively, but reflected, in general, the amino acid turnover known to occur during sporulation.
Enzymatic Oxidation of Tetramethyl-
p
-Phenylenediamine and
p
-Phenylenediamine by the Electron Transport Particulate Fraction of
Azotobacter vinelandii
Authors: Jurtshuk Peter , Aston Patricia R. , Old Lynn
Published: January 2020

The ability of the electron transport particulate fraction of
Azotobacter vinelandii
strain O to oxidize tetramethyl-
p
-phenylenediamine (TMPD) and
p
-phenylenediamine (PPD) was examined in detail. The highest specific activity for TMPD and PPD oxidation concentrated in the
A. vinelandii
O R
3
fraction. The
A. vinelandii
O R
3
fraction was used to develop a standard manometric assay which gave optimal oxidation rates for both of these dyes. The conditions of the assay and all essential related enzymatic kinetic parameters are presented. Other
para
derivatives of phenylenediamines also were oxidized readily, whereas
ortho
and
meta
derivatives were not. Hydroquinone,
p
-hydroxybenzoic acid,
p
-cresol, tyrosine, pyrogallol, pyrocatechol, and diphenylamine were not able to serve as electron donors for the
A. vinelandii
O R
3
system. The probable involvement of a particle-bound cytochrome oxidase is indicated by the marked sensitivity of both TMPD and PPD oxidation to cyanide, axide, phenylhydrazine, hydroxylamine, and, to a lesser degree, carbon monoxide.
Purification and Properties of a Bacteriophage-induced Cell Wall Peptidase from
Staphylococcus aureus
Authors: Doughty C. C. , Mann J. A.
Published: January 2020

A phage-induced cell wall solubilizing enzyme isolated from phage-infected
Staphylococcus aureus
phage type 80 was purified 588-fold. The
p
H optimal activity was 6.8 to 7.3, and
p
H optimal stability, 6.5 to 7.5. It was inhibited by
p
-hydroxymercuribenzoate, ethylenediaminetetraacetic acid, and specific rabbit antisera. The cell wall lytic reaction is a peptidase resulting in cleavage of the cell wall peptide at N-terminal alanine, glutamic acid, and glycine. Electron micrographs are shown of cell wall “ghosts” remaining after the enzymatic digestion of cell walls.
Pleomorphy in Stalked, Budding Bacteria
Authors: Tyler P. A. , Marshall K. C.
Published: January 2020

An investigation of hyphomicrobia from manganese deposits and various fresh-water habitats revealed an astonishing degree of pleomorphy in the group. A range of variation spanning two described genera (
Hyphomicrobium
and
Pedomicrobium
) was induced by varying culture conditions and was further observed in natural environments. It is suggested that
Pedomicrobium
is an invalid genus.
Evidence of Lactate Dehydrogenase in
Anaplasma marginale
Authors: Darré Dianne L. , Wallace W. R. , Dimopoullos G. T.
Published: January 2020

Extracts from preparations of partially purified
Anaplasma marginale
revealed low levels of lactate dehydrogenase (LDH). Enzyme inhibition by immune sera further indicated that
A. marginale
possesses a protein moiety the same as that of the normal red blood cell (RBC), although data suggested an alteration of LDH
1
from that observed in normal RBC. Bimodal isozyme distribution was detected after electrophoresis of the extracts. One isozyme approached the cathode and the other the anode, and both appeared to be nicotinamide adenine dinucleotide-dependent. Heterogeneity of parasite and host cell isozymes was established on the basis of zone electrophoresis on cellulose acetate strips.
Susceptibility of Different Coliphage Genomes to Host-controlled Variation
Authors: Eskridge Rosemary W. , Weinfeld Herbert , Paigen Kenneth
Published: January 2020

Twenty-eight coliphages were studied for their susceptibility to four systems of host control variation in
Escherichia coli
. Both temperate and virulent phages were studied, including phages with ribonucleic acid, double- and single-stranded deoxyribonucleic acid (DNA) and glucosylated DNA. The systems examined were
E. coli
C-K, K-B, B-K, and K-K(P1). The C-K, K-B, and B-K systems affected temperate phages and nonlysogenizing mutants derived from temperate phages. In general, these systems did not restrict virulent phages. Phage 21e, a variant of phage 21, lost the ability to undergo restriction in the C-K and B-K systems, but retained susceptibility to the K-B and K-K(P1) systems. This suggests that the genetic site(s) on the phage, as well as in the host, determines susceptibility to host-controlled variation. Both temperate and dependent virulent phages were susceptible to the host control system resulting from the presence of prophage P1. The autonomous and small virulents were not susceptible. In a given system, the various susceptible phages differed widely in their efficiency of plating on the restricting host. If the few infections that occur arise in rare special cells, then different populations of special cells are available to different phage species. For most phage types, when a susceptible phage infected a nonrestricting host, the progeny showed the specificity appropriate to that host. Behavior of T3 was exceptional, however. When T3 obtained from
E. coli
K infected
E. coli
C or B, some of the progeny phages retained K host specificity, whereas others acquired the specificity of the new host.
Metabolism of Thymineless Mutants of
Escherichia coli
I. Absence of Thymidylate Synthetase Activity and Growth Characteristics of Two Sequential Thymineless Mutants
Authors: Breitman T. R. , Bradford R. M.
Published: January 2020

A study of optimal thymine and deoxythymidine (dThd) growth requirements of the thymineless mutants of
Escherichia coli
15,
E. coli
70–462 (strain 70), and a variant,
E. coli
70V3–462 (strain 70V3), showed that for maximal turbidity (growth) strain 70 required 10-fold greater concentrations of thymine or dThd than did strain 70V3. On suboptimal concentrations of thymine or dThd, growth of strain 70 was greater on dThd than on thymine. In contrast, maximal growth of strain 70V3 was the same on equimolar concentrations of thymine and dThd. Growth rate of strain 70V3 was the same on equimolar concentrations of thymine and dThd up to 4 μ
m
; at concentrations of 5 μ
m
and greater, the “4-hr” growth was lower on dThd than on corresponding concentrations of thymine. Cultures of both thymineless mutants synthesized equal maximal amounts of DNA. Whereas strain 70V3 incorporated a maximum of 90% of the thymine or dThd in the media, strain 70 incorporated a maximum of only 10%. This poor utilization by strain 70 was neither a result of thymine or dThd conversion to a low-molecular-weight thymine derivative nor the production of a nonthymine inhibitory substance. Since strains 70 and 70V3 exhibited no thymidylate synthetase activity, the first mutation (strain 15 to strain 70) resulted in the loss of this activity. The second mutation (strain 70 to strain 70V3) probably brought about the loss of an enzyme(s) that catabolizes deoxyribose phosphate, permitting a greater net synthesis of dThd from thymine.
Purification and Characterization of a Staphylolytic Enzyme from
Pseudomonas aeruginosa
Authors: Burke M. E. , Pattee P. A.
Published: January 2020

A strain of
Pseudomonas aeruginosa
has been shown to produce an enzyme that lyses viable cells of
Staphylococcus aureus
. The maximal yield of the enzyme was obtained from shake flask cultures of
P. aeruginosa
which were grown for 18 to 22 hr at 37 C in Trypticase Soy Broth. A 333-fold purification of the enzyme was obtained by acetone precipitation of the culture liquor, followed by column chromatography on phosphonic acid cellulose and Bio-Gel P2. The staphylolytic enzyme exhibited maximal activity at 37 C in 0.01
m
sodium phosphate (
p
H 8.5) and was stable at 37 C in the
p
H range of 7.5 to 9.5. The inhibition and stabilization of the enzyme by various organic and inorganic materials was investigated. Spheroplasts of
S. aureus
were formed by treating viable cells with the staphylolytic enzyme in 1
m
sucrose or human serum.