bluuebunny/crossref_metadata_2025 huggingface dataset:
Physiology of Rickettsiae VII. Amino Acid Incorporation by
Coxiella burnetii
and by Infected Hosts
Authors: Mallavia L. P. , Paretsky D.
Published: January 2020

Protein synthesis, in terms of
14
C-labeled amino acid incorporation into a hot trichloroacetic acid fraction, was studied in cell-free preparations of
Coxiella burnetii
, and in uninfected and Q fever-infected guinea pig and chick embryo hosts. Purified and disrupted suspensions of
C. burnetii
incorporated
14
C-labeled
l
-leucine,
l
-phenylalanine and algal hydrolysate. Livers of infected guinea pigs and chick embryos had a greater incorporation rate at the height of infection than comparable preparations from uninfected animals. As chick embryonic development continued during infection, the rate of incorporation progressively decreased below that of uninfected embryos.
Response of Intracellular Proteolysis to Alteration of Bacterial Protein and the Implications in Metabolic Regulation
Authors: Pine Martin J.
Published: January 2020

An assessment has been made of the extent to which the breakdown of microbial cellular proteins is regulated by their metabolic state or function. For this purpose, a number of agents and conditions that alter the synthesis, structure, or utility of cellular protein were examined for the effect on their lability. In
Escherichia coli
, 5-fluorouracil,
p
-fluorophenylalanine, norleucine, canavanine, thienylalanine, and puromycin, which engender nonfunctional cellular protein
en masse
, and ultraviolet irradiation increase the breakdown rate of proteins synthesized in their presence as much as two- to threefold without altering the general capacity for proteolysis. The effects are complicated by, but experimentally distinguishable from, secondary changes in proteolysis that accompany growth inhibition. In contrast, no potentiation of proteolysis is elicited by the presence of suppressor genes, by the administration of heat, or by the biosynthetic alterations attending large changes in the conditions of cultivation or by those attending bacteriophage infection. Thus, although mass perturbations in protein conformation are catabolically distinguishable, the more individual and limited conformational modifications that might occur in disuse do not appear to be the primary determinants of the protein turnover rate. In
Bacillus subtilis
, turnover synthesis of protein during starvation is as susceptible to treatment with actinomycin D as that during growth. Treatment alters neither the rate of intracellular proteolysis nor the catabolic pattern of the modicum of proteins that are still synthesized. It is concluded that there is no correlation between metabolic stability of protein and the stability of its messenger ribonucleic acid.
Extracellular Hemolysins of Aerobic Sporogenic Bacilli
Authors: Bernheimer Alan W. , Grushoff Phyllis
Published: January 2020

Forty-five strains, representing 18 species of the genus
Bacillus
, were surveyed for production of hemolysin against rabbit erythrocytes. Broth cultures of
B. cereus, B. alvei
, and
B. laterosporus
contained lysins that closely resembled streptolysin O.
B. subtilis
and a single strain of
B. cereus
may produce lysins having characteristics different from those of streptolysin O.
Changes in Adenine Nucleotides of Intact
Chromatium
D Produced by Illumination
Authors: Gibson Jane , Morita Sigehiro
Published: January 2020

The total adenine nucleotide content of suspensions of
Chromatium
D averaged 14 nmoles/mg of dry weight. Of this, one-third to one-half was adenosine triphosphate (ATP), even in suspensions incubated in darkness. Illumination with high intensities caused a rise in ATP and a drop mainly in adenosine diphosphate, the new steady state being reached in 5 to 15 sec at room temperature. The dark steady state was re-established 15 to 30 sec after returning the suspensions to darkness. The rates of these changes were little affected by the presence of electron donors or CO
2
, though their magnitude was reduced when substrates were added to starved suspensions. At limiting light intensities, complex kinetics characterized the transition from both dark to light and light to dark, and, at lower light intensities, more ATP was produced in suspensions supplemented with electron donors than in starved cells. The results show that photophosphorylation accompanying cyclic electron flow occurred in intact cells, and suggest that noncyclic phosphorylation can also occur.
Effect of Diethylaminoethyl Dextran on the Growth of
Mycoplasma
in Agar
Authors: Tauraso Nicola M.
Published: January 2020

The growth of certain strains of
Mycoplasma
is inhibited by substances present in commercial agar preparations. The addition of diethylaminoethyl (DEAE) dextran (10 mg per 100 ml) to agar media appears to enhance the growth of some strains. Of eight strains initially tested, the presence of DEAE dextran grossly enhanced the growth of three strains. One strain appeared not to be affected, and a clearly enhancing effect was not evident with four strains. Quantitative studies revealed that growth enhancement varied from 10 colony-forming units (CFU) for
M. hominis
type II (strain Campo) to 10
3.3
CFU for
M. pulmonis
(strain 880). The growth-enhancing effect is probably due to the ability of DEAE dextran to bind the sulfated polysaccharide moieties in agar and not to the DEAE dextran, per se.
Catabolite Repression and Pyruvate Metabolism in
Escherichia coli
Authors: Okinaka Richard T. , Dobrogosz Walter J.
Published: January 2020

A study was made of the reactions involved in the cellular regulatory function known as catabolite repression. These studies employed the glucose-repressible, β-galactosidase system of
Escherichia coli
and involved an investigation of glucose dissimilation under cultural conditions capable of permitting or preventing expression of catabolite repression. The results indicated that reactions associated with pyruvate decarboxylation are of particular importance in influencing repression. This conclusion was based on results obtained by measurement of differential rates of C
14
O
2
evolution from specifically labeled
14
C-glucose substrates, and by measurements of H
2
evolution during anaerobic growth. Catabolite repression measured in relation to steady-state growth rates indicated that the repression mechanism may in fact be a direct consequence of a cell's energy balance, as dictated by the production from pyruvate of “high-energy” molecules such as adenosine triphosphate or acetyl-coenzyme A. The apparent involvement of pyruvate metabolism in both the energetics and the expression of catabolite repression in
E. coli
is consistent with this view.
Alteration of the Pathogenicity ofPasteurella pneumotropicafor the Murine Lung Caused by Changes in Pulmonary Antibacterial Activity
Authors: Goldstein Elliot , Green Gareth M.
Published: January 2020

Pasteurella pneumotropicais a potential pulmonary pathogen in mice. In healthy animals, this organism was killed rapidly by the normal function of the intrapulmonary phagocytic defense mechanisms. Impairment of this bactericidal activity by the acute renal failure of nephrectomy resulted in multiplication of thePasteurellain the lung, both when the animals were nephrectomized first and then infected, and when the animals were infected first and nephrectomized several hours after the infection. The study demonstrates that the pathogenicity of thePasteurellaorganisms is governed by the functional state of these pulmonary antibacterial mechanisms.
Carbohydrate Metabolism in Leukocytes VII. Metabolism of Glucose, Acetate, and Propionate by Human Plasma Cells
Authors: Stjernholm Rune L.
Published: January 2020

Plasma cells obtained from the peripheral blood of a patient with multiple myeloma was incubated in serum and Krebs-Ringer bicarbonate buffer with
14
C-labeled glucose, acetate, and propionate. Glucose utilization by these cells amounted to 0.5 μmole per hr per 10
8
cells and was mainly via the Embden-Meyerhof pathway, and only 6% or less traversed the hexose monophosphate shunt. The presence of Krebs cycle activity was demonstrated by direct isolation of several labeled intermediates after incubation with either
14
C-acetate or
14
C-propionate. The distribution of
14
C in lactate, succinate, fumarate, malate, aspartate, and glutamate indicate a complete Krebs cycle. Acetate was metabolized via the Krebs cycle to the extent of 0.15 μmoles per hr per 10
8
cells, and the rate of propionate utilization was 0.17 μmoles per hr per 10
8
cells.
Measurement of Binding of Chloramphenicol by Intact Cells
Authors: Hurwitz Charles , Braun Catherine B.
Published: January 2020

The binding of chloramphenicol to intracellular components of intact cells was measured by procedures based on a silicone-wash technique. The number of stereospecifically bound molecules of chloramphenicol increased with external concentration to a saturation value equal to the number of ribosomes per cell. Chloramphenicol is therefore believed to be attached stereospecifically by a weak bond, most probably to a single site on the 50
S
ribosome. This bond was found to be temperature-dependent and appeared to be responsible for inhibition of protein synthesis.
Culture of Serum-induced Spheroplasts fromVibrio cholerae
Authors: Iannetta Antoinette , Wedgwood Ralph J.
Published: January 2020

Spheroplasts ofVibrio choleraetypes Inaba, Hikojima, and Ogawa were produced in serum. An excess of lysozyme was added to expedite transformation, and CaCl2was used as the stabilizing agent. At the optimal time for each strain, when less than 1% classical rod forms were observed microscopically, samples were plated on both conventional and modified L-form media. No growth occurred on conventional media; L-form type colonies appeared on L-form media after 2 to 6 days of incubation. L-form colonies could be subcultured on conventional media and required from four to six passages for complete reversion to classical parent forms. Reaction mixtures of Hikojima and Inaba types were passed through membrane filters (0.45 μ); L-form colonies were grown from both strains after spheroplast transformation. Appropriate controls were negative. It is suggested that the replicative particle may be filtrable.
Enzyme-induced Formation of Spheres from Cells and Envelopes of
Escherichia coli
Authors: Weinbaum George , Rich Ruthann , Fischman Donald A.
Published: January 2020

Normal and filamentous whole cells and isolated envelopes of
Escherichia coli
B were exposed to various enzymatic treatments to remove surface layers and to characterize the component(s) conferring rigidity in this organism. Modification of cell rigidity was determined by sphere formation in both whole cells and isolated envelopes. Enzymes capable of converting trypsinized normal or untreated filamentous whole cells and untreated envelopes to spheres included: lysozyme plus ethylenediaminetetraacetic acid, clostridial phospholipase C, and phospholipase D from cabbage. These data suggest that there are at least two components essential for maintenance of cell rigidity in
E. coli
B. The first is the peptidoglycan (mucopeptide), which is susceptible to lysozyme. The second is a phospholipid which is either covalently linked to the mucopeptide or in close association with it. This phospholipase C-sensitive component is protected more completely in normal than in filamentous whole cells by a protein layer which is easily modified by trypsin treatment to allow enzymatically induced sphere formation to occur.
Preferential Inhibition of Penicillinase Induction by Oxytetracycline and Its Effect on the Penicillin Susceptibility of Staphylococci
Authors: Michael Thomas M. , Michael J. Gabriel , Massell Benedict F.
Published: January 2020

Exposure of penicillinase-producing staphylococci to a combination of penicillin and oxytetracycline resulted in a synergistic inhibitory activity of the antibiotics on the bacteria. Oxytetracycline was employed in concentrations having little or no effect on bacterial growth. It was found that the synergistic antibacterial effect was caused by the preferential inhibition of penicillinase induction by oxytetracycline, rendering the staphylococci more susceptible to penicillin.
Effect of Glucose on Carbon Dioxide Assimilation and Substrate Oxidation by
Ferrobacillus ferrooxidans
Authors: Silver Marvin , Margalith P. , Lundgren D. G.
Published: January 2020

Ferrobacillus ferrooxidans
, grown on either elemental sulfur or ferrous sulfate, was able to use either substrate as an energy source for the assimilation of CO
2
. In both cases, 0.01 μmole of carbon was incorporated per μmole of oxygen utilized. Glucose inhibited substrate oxidation and CO
2
fixation. Sulfur and iron oxidation were inhibited 5 to 15% and 40 to 50%, respectively, in the presence of 10% glucose. Under the same conditions, CO
2
assimilation was inhibited 50% with elemental sulfur as the energy source, and was almost totally inhibited when ferrous iron was used.
Formation and Operation of the Histidine-degrading Pathway in
Pseudomonas aeruginosa
Authors: Lessie Thomas G. , Neidhardt Frederick C.
Published: January 2020

Histidine ammonia lyase (histidase), urocanase, and the capacity to degrade
formiminoglutamate, which are respectively involved in steps I, II, and IV in
the catabolism of histidine, were induced during growth of
Pseudomonas
aeruginosa
on histidine or urocanate, and were formed gratuitously
in the presence of dihydro-urocanate. Urocanase-deficient bacteria formed
enzymes I and IV constitutively; presumably they accumulate enough urocanate
from the breakdown of endogenous histidine to induce formation of the pathway.
Urocanate did not satisfy the histidine requirement of a histidine auxotroph,
indicating that it probably acted as an inducer without being converted to
histidine. The results imply that urocanate is the physiological inducer of the
histidine-degrading enzymes in
P. aeruginosa
. Enzymes of the
pathway were extremely sensitive to catabolite repression; enzymes I and II, but
not IV, were coordinately repressed. Our results suggest a specific involvement
of nitrogenous metabolites in the repression. Mutant bacteria with altered
sensitivity to repression were obtained. The molecular weight of partially
purified histidase was estimated at 210,000 by sucrose gradient centrifugation.
Its
K
m
for histidine was 2 ×
10
−3
m
in tris(hydroxymethyl)aminomethane
chloride buffer. Sigmoid saturation curves were obtained in pyrophosphate
buffer, indicating that the enzyme might have multiple binding sites for
histidine. Under certain conditions, histidase appeared to be partially inactive
in vivo. These findings suggest that some sort of allosteric interaction
involving histidase may play a role in governing the operation of the pathway of
histidine catabolism.
Aliphatic Hydrocarbons and Fatty Acids of Some Marine and Freshwater Microorganisms
Authors: Oró J. , Tornabene T. G. , Nooner D. W. , Gelpi E.
Published: January 2020

Gas chromatography and combined gas chromatography-mass spectrometry have been used to study the fatty acids and hydrocarbons of a bacterium from the Pacific Ocean,Vibrio marinus, a freshwater blue-green alga,Anacystis nidulans, and algal mat communities from the Gulf of Mexico. Both types of microorganisms (bacteria and algae) showed relatively simple hydrocarbon and fatty acid patterns, the hydrocarbons predominating in the region of C-17 and the fatty acids in the range of C-14 to C-18. The patterns ofV. marinuswere more comparable to those of the algal populations than to patterns reported for other bacteria. An incomplete correlation between fatty acids and hydrocarbons in both types of organisms was observed, making it difficult to accept the concept that the biosynthesis of hydrocarbons follows a simple fatty acid decarboxylation process.
Biochemical and Genetic Analysis of Isoleucine and Valine, Biosynthesis in
Staphylococcus aureus
Authors: Smith C. D. , Pattee P. A.
Published: January 2020

After a prototrophic strain of
Staphylococcus aureus
had been exposed to diethyl sulfate, 28 isoleucine- and isoleucine-valine-dependent mutants (
ilv
mutants) were isolated. On the basis of auxanography, their ability to accumulate intermediates of isoleucine and valine biosynthesis, and intergeneric syntrophism with
ilv
mutants of
Salmonella typhimurium
, all mutants were placed into four groups, each of which corresponded to a presumed enzymatic deficiency, as follows: group A, deficient in
l
-threonine deaminase; group B, deficient in the condensing enzyme; group C, deficient in reductoisomerase; group D, deficient in α-β-dihydroxy acid dehydrase. No mutants blocked in the terminal (transaminase) reactions were isolated. Transduction analyses (best-fit, ratio, and complementation tests) with the use of phage 83 established that the linear arrangement of the structural genes is identical with the order of participation of their enzymes in isoleucine and valine biosynthesis, and that these genes comprise a single linkage group which can exist on a single donor fragment during transduction.
Degradation of Hydrocarbons by Members of the Genus
Candida
II. Oxidation of
n
-Alkanes and 1-Alkenes by
Candida lipolytica
Authors: Klug M. J. , Markovetz A. J.
Published: January 2020

Candida lipolytica
ATCC 8661 was grown in a mineral-salts hydrocarbon medium.
n
-Alkanes and 1-alkenes with 14 through 18 carbon atoms were used as substrates. Ether extracts of culture fluids and cells obtained from cultures grown on the various substrates were analyzed by thin-layer and gas-liquid chromatography. Analyses of fluids from cultures grown on
n
-alkanes indicated a predominance of fatty acids and alcohols of the same chain length as the substrate. In addition, numerous other fatty acids and alcohols were present. Analyses of saponifiable and nonsaponifiable material obtained from the cells revealed essentially the same products. The presence of primary and secondary alcohols, as well as fatty acids, of the same chain length as the
n
-alkane substrate suggested that attack on both the methyl and α-methylene group was occurring. The significance of these two mechanisms in the degradation of
n
-alkanes by this organism was not evident from the data presented. Analyses of fluids from cultures grown on 1-alkenes indicated the presence of 1,2-diols, as well as ω-unsaturated fatty acids, of the same chain length as the substrate. Alcohols present were all unsaturated. Saponifiable and nonsaponifiable material obtained from cells contained essentially the same products. The presence of 1,2-diols and ω-unsaturated fatty acids of the same chain length as the substrate from cultures grown on 1-alkenes indicated that both the terminal methyl group and the terminal double bond were being attacked.
Orthophosphite-Nicotinamide Adenine Dinucleotide Oxidoreductase from
Pseudomonas fluorescens
Authors: Malacinski George M. , Konetzka W. A.
Published: January 2020

Information was obtained on the general properties and specificity of orthophosphite-nicotinamide adenine dinucleotide oxidoreductase. The enzyme was extracted from
Pseudomonas fluorescens
195 grown in medium containing orthophosphite as the sole source of phosphorus. An enzyme preparation suitable for characterization was obtained from crude extracts by use of high-speed centrifugation, protamine sulfate precipitation, ammonium sulfate fractionation, and Sephadex gel filtration. The enzyme exhibited maximal activity at
p
H 7.0, and was inactivated within 6 min at 37 C. Arsenite, hypophosphite, nitrite, selenite, and tellurite were not oxidized by the enzyme. Sulfite inhibited the enzymatic oxidation of orthophosphite in an apparent competitive manner.
Inhibition and Agglutination of Arthrobacters by Pseudomonads
Authors: Sieburth John McN.
Published: January 2020

The bacterial flora of water in Narragansett Bay, R.I., was observed semimonthly from 1962 to 1964. Dominant isolates were keyed to genus, and the isolates for each genus were expressed as percentage of total isolates. There was a consistent inverse relationship between arthrobacters and the dominant pseudomonads. Pseudomonad growth on agar plates markedly inhibited arthrobacter cross-streaks. Agar from inhibition zones as well as supernatant fluids from pseudomonad broth cultures inhibited arthrobacter motility and caused the cells to agglutinate. Gummy pseudomonad residues from vacuum-evaporated broth cultures readily passed a G-25 Sephadex column. This material agglutinated arthrobacter cells, but failed to cause arthrobacter inhibition in filter-pad assays. In contrast, sterile medium inside a dialysis sac, inoculated externally with a pseudomonad, was inhibitory to arthrobacters in pad assay but failed to agglutinate arthrobacter cells. Pseudomonad isolates from soil showed similar inhibiting and agglutinating activities for both soil and seawater arthrobacter isolates. The inhibitory and agglutinating activities of pseudomonad isolates appeared to diminish on prolonged laboratory cultivation.
Thymineless Death in
Escherichia coli:
Strain Specificity
Authors: Cummings Donald J. , Mondale Lee
Published: January 2020

Thymineless death of various ultraviolet (UV)-sensitive strains of
Escherichia coli
B and K-12 was investigated. It was found that
E. coli
B, B
s−12
, K-12
rec-21
, and possibly K-12 Lon
−
, all sensitive to UV, were also sensitive to thymine starvation. However, other UV-sensitive strains of
E. coli
were found to display the typical resistant-type kinetics of thymineless death. The correlation of these results with various other cellular processes suggested that the filament-forming ability of the bacteria might be involved in the mechanism of thymineless death. It was apparent from the present results that capacity for host-cell reactivation, recombination ability, thymine dimer excision, and probably induction of a defective prophage had little to do with determining sensitivity to thymine deprivation.
Transformation and Transduction in Recombination-defective Mutants of
Bacillus subtilis
Authors: Hoch J. A. , Barat M. , Anagnostopoulos C.
Published: January 2020

The effects on transformation and transduction of an ultraviolet sensitivity (
uvr
−
) and two ultraviolet sensitivity-recombination deficiency (
rec-1
−
and
rec-2
−
) mutations in isogenic strains of
Bacillus subtilis
were investigated. Transformation frequency in the
rec-1
−
and
rec-2
−
strains was reduced to approximately 5 and 25%, respectively, of the parental strains. Normal kinetics of deoxyribonucleic acid dose response in transformation were found for the
rec-1
+
and
rec-2
−
strains. Biphasic curves were obtained with the
rec-1
−
strains. Transduction frequency with bacteriophage SP-10 decreased parallel to transformation frequency in the
rec-1
−
and
rec-2
−
strains. This result suggests that transformation and SP-10 transduction share a common mechanism for genetic recombination. It also indicates that the reduction in transformation frequency of these strains was not due to altered competence. Transduction frequency with bacteriophage PBS-1 or 3NT, on the contrary, was not diminished in
rec-1
−
strains. This frequency was reduced in
rec-2
−
strains but not as severely as that of transformation or SP-10 transduction. Several hypotheses to interpret these differences are presented. Recombination frequency between linked markers was reduced more than 50% in transformation by the presence of the
rec-1
−
mutation. Linkage was unaffected in the
rec-2
−
strains. Neither the
rec-1
−
nor the
rec-2
−
mutation had an effect on linkage in PBS-1 or 3NT transduction. The
uvr
−
strains were transformed at a frequency equal to or greater than that of the parental strains. These strains were transduced by all bacteriophage systems at frequencies about twofold higher than those of parental strains.
Evaluation of Fluorescein Isothiocyanate-labeled Whole Antiserum in the Immunofluorescent Identification of Microorganisms
Authors: Sweet George H. , Schindler Charles A.
Published: January 2020

Portions of a whole antiserum toHistoplasma capsulatumwere reacted with amounts of fluorescein isothiocyanate (FITC) that ranged from 50 to 400 μg/mg of protein. Portions of the globulin from the same antiserum were reacted with amounts of FITC that ranged from 12.5 to 50 μg of FITC per mg of protein. The globulin conjugates (postlabeled globulins), the whole serum conjugates, and the globulins from the whole serum conjugates (prelabeled globulins) were compared with respect to their fluorescein-protein (F:P) ratios and fluorescent-antibody (FA) activities. The whole serum sample treated with 50 μg of FITC per mg of protein was least reactive in FA tests, and its globulin had the lowest F:P. All other conjugates had globulins with F:P ratios that were considered to be adequate for high FA activity. It was found, however, that the prelabeled globulins were considerably less reactive than the postlabeled globulins or the whole serum conjugates. A larger amount of brightly staining reagent per milliliter of original serum could be obtained from labeled whole serum than from postlabeled globulin. Lissamine-rhodamine conjugated to bovine serum albumin (LRBSA) was evaluated as a counterstain to be used in conjunction with FITC-labeled whole antisera. The counterstain was effective in masking nonspecific FITC fluorescence in Formalin-fixed tissues and in culture smears of fungi. Masking was incomplete in culture smears of a bacterium and in blood smears containing a protozoan.
Ultrastructure of the Cell Wall of
Bacillus polymyxa
Authors: Nermut M. V. , Murray R. G. E.
Published: January 2020

The macromolecular arrangement on the surface of
Bacillus polymyxa
was revealed by metal shadowing of whole cells and wall fragments; it consisted of a rectangular array of 70-A globules with a repeating interval of 100 A. The substructure was studied in plan with phosphotungstic acid (
p
H 6) or uranyl acetate as negative stains of fragments and was studied also in profile with sections of embedded material. Staining of sections of cells fixed with glutaraldehyde showed that layering (approx. 80-A dense, 40-A light, and 120-A dense layers, outermost layer first) could be demonstrated in the cell wall with lead or uranyl acetate, used together or separately. The outer “dense” layer corresponded to the regularly arrayed structure (RS); it was removed by guanidine hydrochloride, sodium lauryl sulfate, cold formamide, and by trypsin. The RS layer (isolated by a hydrogen bond breaking reagent, guanidine hydrochloride) was disrupted by agents such as sodium lauryl sulfate or damaged by 3
m
sodium chloride. Qualitative chemical tests, ultraviolet absorption, and removal by trypsin indicated that the structured layer consisted mainly of protein, but exact characterization was not attempted. The globular units making up the layer consisted of a small number of subunits, imperfectly resolved by negative staining. The underlying polysaccharide appeared to be covalently bound to the deepest (probably mucopeptide) layer since it required “hot” formamide for its removal. A survey of species was not made.
Electron Microscopy of the Lysis ofStaphylococcus aureusCell Walls byAeromonasLytic Factor
Authors: Gilbo C. M. , Beaton C. D. , Coles N. W.
Published: January 2020

Isolated and purified cell walls ofStaphylococcus aureuswere treated with a purified fraction of the culture supernatant fluid of a species ofAeromonas. The course of lysis of the cell walls was followed over a period of time by examination of samples under an electron microscope. The undifferentiated cell wall was rapidly digested, but the equatorial rings were more resistant. The undifferentiated cell wall became a very thin sheet before completely dissolving, leaving a series of equatorial rings of various widths. As digestion proceeded, solubilization of the entire cell wall occurred. Analogous findings were obtained with purifiedS. aureusmucopeptide. It is concluded that theAeromonaslytic principle is an enzyme, and that susceptible bonds are more concentrated in the undifferentiated cell wall mucopeptide.
Electron Microscopy of Chloramphenicol-treated
Escherichia coli
Authors: Morgan Councilman , Rosenkranz Herbert S. , Carr Howard S. , Rose Harry M.
Published: January 2020

Thin sections of
Escherichia coli
were examined by electron microscopy at sequential intervals after addition and then removal of chloramphenicol. The first changes, occurring at 1 hr after exposure to the drug, were disappearance of the ribosomes and aggregation of the nuclear material toward the center of the bacteria. At 2 hr, aggregates of abnormal cytoplasmic granules first appeared and subsequently increased in size. By 23 hr, amorphous, electron-dense material had accumulated within, and at the periphery of, the nuclear matrix. With the removal of chloramphenicol, the bacteria became normal in appearance, passing through a series of stages that were sequential but not synchronous. At 145 min after removal of chloramphenicol, bacteria were encountered in the process of abnormal division. The influence of deoxyribonucleic acid and ribonucleic acid synthesis, and of energy metabolism, upon the changes seen electron microscopically in chloramphenicol-treated cells, was investigated by selectively inhibiting these functions with hydroxyurea, azauracil, and sodium azide, respectively.
Isolation and Characterization of
Actinomyces propionicus
Authors: Gerencser Mary Ann , Slack John M.
Published: January 2020

Three cultures of
Actinomyces
have been identified as
Actinomyces propionicus
. Two of these strains are recent isolates, one, 427, from a case of cervico-facial actinomycosis, and one, 439, from a case of lacrimal canaliculitis. The third strain, 346, was described by F. Lentze as
A. israelii
serological type II. These three strains were compared with the type strain of
A. propionicus
ATTC 14157 and with known strains of five other
Actinomyces
species. Morphologically and biochemically the three new cultures of
A. propionicus
were identical with the type strain but closely resembled
A. israelii
. In serological tests making use of fluorescent antibody, all four
A. propionicus
strains gave negative results with antisera for
A. israelii, A. bovis, A. naeslundii
, and
A. eriksonii
, but gave positive results with antisera for
A. propionicus
14157 and strain 346. The
A. propionicus
antisera did not stain other
Actinomyces
species.
A. propionicus
contains diaminopimelic acid (DAP) in its cell wall and produces propionic acid from glucose. All three new isolates were shown to contain DAP and to produce propionic acid. By use of the presence of DAP in the cell wall and serological tests as the differential criteria, the three cultures described in the report were specifically identified as
A. propionicus
.
Synthesis of Macromolecules by
Escherichia coli
near the Minimal Temperature for Growth
Authors: Shaw Maxwell K. , Ingraham John L.
Published: January 2020

When a culture of
Escherichia coli
ML30 growing exponentially at 37 C in a glucose minimal medium was shifted abruptly to 10 C, growth decreased for about 4.5 hr. There was no net synthesis of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein. The cells, however, respired at a rate characteristic of cells growing in the steady state at 10 C and were able to accumulate α-methyl-
d
-glucoside. When growth recommenced at 10 C, protein synthesis started at 4 hr, RNA synthesis, with a burst at 6 hr, and DNA synthesis, with a burst at 7 hr. One synchronous division occurred at about 11 hr after shifting to 10 C. There was no alteration in the steady-state RNA to protein ratio. The results are discussed in relation to other reported effects of shifts in environmental conditions. The lag at 10 C was dependent on prior conditions of growth at 37 C. Growth at 37 C under conditions giving catabolite repression were necessary for the lag to be established on shifting to 10 C.
Inhibition of Rumen Methanogenesis by Methane Analogues
Authors: Bauchop T.
Published: January 2020

Extremely low concentrations of chloroform and carbon tetrachloride and somewhat larger concentrations of methylene chloride inhibited the formation of methane by the rumen microbiota in the presence or absence of added substrate. The accumulation of hydrogen at these low concentrations indicates a selective inhibition of methanogenesis. Presumably, these inhibitors affect one or more of the reactions by which methane is formed from hydrogen and carbon dioxide.
Aerobic Metabolism of
Streptococcus agalactiae
Authors: Mickelson M. N.
Published: January 2020

Streptococcus agalactiae
cultures possess an aerobic pathway for glucose oxidation that is strongly inhibited by cyanide. The products of glucose oxidation by aerobically grown cells of
S. agalactiae
50 are lactic and acetic acids, acetylmethylcarbinol, and carbon dioxide. Glucose degradation products by aerobically grown cells, as percentage of glucose carbon, were 52 to 61% lactic acid, 20 to 23% acetic acid, 5.5 to 6.5% acetylmethylcarbinol, and 14 to 16% carbon dioxide. There was no evidence for a pentose cycle or a tricarboxylic acid cycle. Crude cell-free extracts of
S. agalactiae
50 possessed a strong reduced nicotinamide adenine dinucleotide (NADH
2
) oxidase that is also cyanide-sensitive. Dialysis or ultrafiltration of the crude, cell-free extract resulted in loss of NADH
2
oxidase activity. Oxidase activity was restored to the inactive extract by addition of the ultrafiltrate or by addition of menadione or K
3
Fe(CN)
6
. Noncytochrome iron-containing pigments were present in cell-free extracts of
S. agalactiae
. The possible participation of these pigments in the respiration of
S. agalactiae
is presently being studied.
Mutator Gene of
Escherichia coli
B
Authors: Siegel Eli C. , Bryson Vernon
Published: January 2020

An azaserine-resistant derivative of
Escherichia coli
B/UV, AZA/R
1
, was found to carry a mutator gene. This gene, designated
mutS1
, was mapped by means of conjugation and P1kc-mediated transduction. The
mutS1
gene was cotransduced with
argB
at a frequency of 2.4%; the gene order in this region of the chromosome is
thy argB mutS1
. To determine whether a relationship commonly exists between azaserine resistance and the mutator property, 12 additional azaserine-resistant derivatives of B/UV were developed and tested for the mutator phenotype. None of the twelve was a mutator strain. The level of azaserine resistance was not increased over that of the recipient parent when
mutS1
was transduced to an azaserine-susceptible strain. Reversion studies indicated that
mutS1
induced adenosine-ribosylthymine to guanosine-cytidine and guanosine-cytidine to adenosine-ribosylthymine transitions. Because such mutational changes are suppressible with deoxynucleosides when induced by base analogues, an attempt was made to suppress the mutator activity of
mutS1
by the addition of deoxyribonucleosides to the medium. No suppression was found. Recombinants were prepared containing
mutS1
and the Treffers mutator gene of
E. coli
K-12. The effect of the mutator genes appears to be additive.
Gramicidin, Valinomycin, and Cation Permeability of
Streptococcus faecalis
Authors: Harold F. M. , Baarda J. R.
Published: January 2020

Gramicidin and valinomycin in concentrations of 10
−7
and 10
−6
m
, respectively, inhibited the growth of
Streptococcus faecalis
. Inhibition of growth was associated with loss of Rb
+
and K
+
from the cells, and could be reversed by addition of excess K
+
. Cells treated with these antibiotics exhibited greatly increased permeability to certain cations; no effect was observed on the penetration of other small molecules. Unlike normal cells, cells treated with gramicidin rapidly lost internal Rb
+
by passive exchange with external cations, including H
+
, all monovalent alkali metals, NH
4
+
, Mg
++
, and tris(hydroxymethyl)aminomethane. Exchange was rapid even at 0 C and was independent of energy metabolism. The effect of valinomycin was more selective. Cellular Rb
+
was rapidly displaced by external H
+
, K
+
, Rb
+
, and Cs
+
; other cations were less effective. The exchange was independent of metabolism but strongly affected by temperature. Under certain conditions, polyvalent cations inhibited exchange between
86
Rb and Rb
+
induced by valinomycin. The antibiotic apparently neither stimulates nor inhibits the energy-dependent K
+
pump of
S. faecalis
, but exerts its effect on the passive permeability of the membrane to cations. The increased permeability to specific cations induced by gramicidin and valinomycin is a sufficient explanation for the inhibition of growth, glycolysis, and other processes.
Derepression of Alkaline Phosphatase in
Escherichia coli
by
p
-Fluorophenylalanine
Authors: Kang Soosang , Markovitz Alvin
Published: January 2020

p
-Fluorophenylalanine (FPA) causes a 100-fold increase in alkaline phosphatase in
Escherichia coli
B, strain PR1 at 30 C in minimal medium that contains excess inorganic phosphate (1.92 × 10
−3
m
). Little increase in alkaline phosphatase synthesis occurs under these conditions at 22 C. [This strain is known to have a mutation in a regulator gene (
R
2
) that, in the absence of FPA, permits derepression of alkaline phosphatase synthesis at 37 C, but not at 30 C or below.] In contrast,
E. coli
B3 (the strain from which
E. coli
B strain PR1 was derived) is not derepressed at 30 C by FPA.
14
C-FPA is incorporated into bacterial proteins. Temperature-shift experiments (30 C⇌22 C) in the presence of FPA are consistent with the following mechanism. FPA is incorporated into the genetically altered R
2
protein at 30 and 22 C. This further alteration due to the incorporation of analogue makes the R
2
protein inactive at 30 C, but active at 22 C.
Group Q Streptococci II. Nutritional Characteristics and Growth Relationship to Thymine, Folate, and Folinate
Authors: Nowlan Sandra Simpson , Deibel R. H.
Published: January 2020

The vitamin requirements of the group Q streptococci (
Streptococcus avium
) and the established enterococcal species (
S. faecalis
and
S. faecium
) paralleled one another, although
S. avium
did not characteristically require riboflavine or pyridoxal.
S. avium
was further differentiated in that it required thymine for growth initiation whether or not folate was present. Folate was stimulatory in the presence of sub-optimal concentrations of thymine, as well as during the early growth period with optimal thymine concentrations. Folinate completely replaced the thymine requirement, and the
S. avium
strains required significantly higher concentrations than did
Pediococcus cerevisiae
8081. The requirement pattern for folate and related compounds was compared, and marked differences were observed in the requirements of
S. faecalis, S. faecium, S. avium
, and
P. cerevisiae
.
Inhibition of Growth of
Escherichia coli
and of Homoserine
O
-Transsuccinylase by α-Methylmethionine
Authors: Schlesinger Sondra
Published: January 2020

The methionine analogue, α-methylmethionine, inhibits bacterial growth, but its action is overcome by methionine, homocysteine, and cystathionine. The effect of the analogue on growth is attributed to its ability to mimic methionine as a feed-back inhibitor of the first enzyme specific to methionine biosynthesis. This conclusion is based on the findings that (i) α-methylmethionine inhibits excretion of
O
-succinylhomoserine, the product of the first enzyme, by a methionine auxotroph unable to convert succinylhomoserine to cystahionine, and that (ii) the enzyme homoserine
O
-transsuccinylase is inhibited by α-methylmethionine in extracts of
Escherichia coli
. α-Methylmethionine also inhibits methionyl-ribonucleic acid synthetase in extracts, but this inhibition probably does not affect growth.
Electrophoretic Patterns of Membrane Proteins of
Mycoplasma
Authors: Rottem Shlomo , Razin Shmuel
Published: January 2020

Cell membranes of
Mycoplasma
were isolated either by osmotic lysis or by ultrasonic disruption of the organisms. The membranes were dissolved in phenol-acetic acid-water (2:1:0.5, w/v/v), and membrane proteins were separated electrophoretically in polyacrylamide gels containing 5
m
urea and 35% (v/v) acetic acid. The electrophoretic patterns of membrane proteins were highly specific for the different
Mycoplasma
strains examined. The use of this method to prove the identity or dissimilarity of
Mycoplasma
strains is suggested.
A Comparative Study of Two F-like Colicin Factors, ColV2 and ColV3, in
Escherichia coli
K-12
Authors: Macfarren Adelaide C. , Clowes R. C.
Published: January 2020

Of three colicin factors, each determining the synthesis of a colicin V in three wild-type
Escherichia coli
strains studied, two were shown to have sex-factor activities. In
E. coli
K-12, these activities resembled those of the F sex factor (including rapid and efficient self-transmission in exponentially growing cultures, adsorption of “male-specific” ribonucleic acid phage, production of “female phenocopies,” elimination by acridine orange, and chromosomal transfer dependent upon recombination with host bacterium) and differed in this way from those of the colicin I sex factor (ColI). The two V factors, ColV2 and ColV3, differed in their efficiency of plating male-specific phage and in the pattern of transfer of chromosomal markers. Furthermore, although neither factor could stably coexist with F within the same cell, they showed markedly different exclusion effects. In general, ColV2 excluded F and ColV3 was excluded by F, irrespective of which sex factor was preestablished in the cell. An exception to this was the ability of ColV2 to stabilize in any one of a series of Hfr strains, giving rise to strains which in the majority of cases showed normal Hfr and colicinogenic properties.
Role of Complement in Immune Inactivation of
Mycoplasma gallisepticum
Authors: Barker L. F. , Patt J. K.
Published: January 2020

Studies were undertaken to evaluate the role of complement in the interaction between mycoplasmas and antiserum. A suspension of the A-1 strain of
Mycoplasma gallisepticum
in PPLO broth was incubated at 37 C with rabbit immune serum which had been heated for 30 min at 56 C. Samples were removed from the mixture at timed intervals for 1 hr for titration of the mycoplasmas in broth. When normal guinea pig serum was included in the mixture at a final dilution of 1:40, the titer fell rapidly from 10
6
to 10
2
organisms per 0.2 ml. When the guinea pig serum was heated for 30 min at 56 C or was omitted from the mixture, the immune serum did not reduce the titer. The rate of inactivation was related to the final concentration of antiserum and to the incubation temperature. The effect of the guinea pig serum was eliminated by the addition of 0.01
m
sodium ethylenediaminetetraacetate or by prior absorption with an unrelated antigen-antibody complex. It was concluded that complement-like substances play an important role in immune inactivation of
M. gallisepticum
.
Effect of Adenosine Monophosphate, Adenosine Diphosphate, and Reduced Nicotinamide Adenine Dinucleotide on Adenosine Triphosphate-dependent Carbon Dioxide Fixation in the Autotroph
Thiobacillus neapolitanus
Authors: Mayeux Jerry V. , Johnson Emmett J.
Published: January 2020

The observation that adenosine triphosphate (ATP)-dependent CO
2
fixation in extracts of chemosynthetic and photosynthetic autotrophs may be regulated in part by adenosine monophosphate (AMP) was extended to the strict autotroph
Thiobacillus neapolitanus
(X). In addition, this report presents data which include adenosine diphosphate (ADP) in the regulatory role. When the primary CO
2
acceptor, ribose-5-phosphate, was replaced by ribulose-1,5-diphosphate, no inhibition of CO
2
fixation occurred unless the Mg
++
concentration was limiting. A molar ratio of 5:1 AMP or ADP to ATP reduced the specific activity (micromoles of CO
2
fixed per milligram of protein per minute) of the extracts from 0.22 to 0.12 and 0.11, respectively. The reported stimulation of the carboxylative phase of ATP-dependent CO
2
fixation by reduced nicotinamide adenine dinucleotide (NADH
2
) was investigated. Adding NADH
2
to the extracts did not stimulate CO
2
fixation, even at carbonate levels from 0.05 to 30 μmoles, except in the absence of ribose-5-phosphate. Slight increases in CO
2
fixation were noted when the assay system was incubated in air instead of the usual helium atmosphere.
Fine Structure of
Bacillus megaterium
during Microcycle Sporogenesis
Authors: Freer John H. , Levinson Hillel S.
Published: January 2020

Ultrathin sections were prepared from cultures of
Bacillus megaterium
QM B1551 undergoing microcycle sporogenesis (initial spore to primary cell to second-stage spore without intervening cell division) on a chemically defined medium. The cytoplasmic core of the dormant spore was surrounded by plasma membrane, cell-wall primordium, cortex, outer cortical layer, and spore coats. Early in the cycle, the coat opened at the germinal groove, the cortex swelled, ribosomes and a chromatinic area associated with large mesosomes (which may later be incorporated into the expanding plasma membrane) appeared in the core, and the cell wall became defined at the site of the cell wall primordium. Poly-β-hydroxybutyrate granules began to appear in the primary cell at about 3 hr. By 7 hr, the forespore of the second-stage spore was delineated by typical double membranes. Between 7 and 12 hr, second-stage cell-wall primordium and cortex developed between the separating forespore membranes. The inner membrane became the plasma membrane of the second-stage spore, and the outer membrane eventually disintegrated within the second-stage spore cortex. A densely staining double layer (spore-coat primordium) developed external to the outer forespore membrane. The inner spore coat and the outer cortical layer of the second-stage spore developed from this primordium. The outer part of the spore coat, probably of sporangial origin, was laid down on the external surface of the inner spore coat. By 12 hr, second-stage spores were almost mature. By 20 hr, the mature endospores, with a thickened outer coat, were often still enclosed by degenerate primary cell wall and by the outer cortical layer and spore coat of the initial spore.
Membranes of
Saccharomyces cerevisiae
Authors: Klein Harold P. , Volkmann Carol , Weibel Joseph
Published: January 2020

A crude small particle pellet, obtained from postmitochondrial supernatant fractions of
Saccharomyces cerevisiae
, contains about half the ergosterol and phospholipid of crude cell homogenates. Most of the phospholipid of this pellet is in a “heavy” fraction which, with the aid of electron microscopy, shows membranous elements in addition to discrete particles. The “heavy” fraction, upon treatment with deoxycholate, can be freed of membranes, or, with ribonuclease treatment, ribosomes can be removed, leaving relatively clean membranes. The “heavy” fraction resembles the microsomes of animal cells, but contains considerably less lipids, including phospholipids, thus suggesting a less well-developed intracellular membrane system.
Release of Sporangiospores by a Strain of
Actinoplanes
Authors: Higgins Michael L.
Published: January 2020

Dehiscence of
Actinoplanes
sp. 7–10 sporangia is triggered by wetting of the spores. This process requires time because of the hydrophobic nature of the sporangial envelope; it can be speeded up and enhanced by a wetting agent. Once wetted, the spores swell, usually ripping the sporangial wall, and escape as motile elements when functional flagella are synthesized. Flagellation and motility are separate phenomena, both of which lose intensity with age. Spores from old sporangia can regain motility when supplied with an exogenous carbon source, but, when provided only with water, phosphate buffer, or amino acids, flagellation takes place without motility. Deflagellation-reflagellation experiments indicated that functional flagella can be reformed only in presence of both amino acids and glucose which must be added within 180 min of deflagellation. Inoperative flagella were formed in the presence of inhibitors of nucleic acid synthesis, such as 6-azauracil, but inhibitors of protein synthesis, such as chloramphenicol, did not interfere with reflagellation. Flagellated spores remained so after germination.