bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphology and Reproductive Processes of the L Forms of Bacteria II. Comparative Study of L Forms and
Mycoplasma
with the Electron Microscope
Authors: Dienes Louis , Bullivant Stanley
Published: January 2020

Representative electron micrographs, from the study of eight strains of L forms and one strain of
Mycoplasma
, are presented. A- and B-type L forms were derived from two strains of
Proteus
, two other L forms were derived from a diphtheroid and from a staphylococcus strain, and two strains (designated as LX) were isolated from L forms derived from a group A β-hemolytic streptococcus and from a staphylococcus. The
Mycoplasma
strain was isolated from goats. Sections were made of young colonies grown within agar and from parts of surface colonies embedded in the agar. B-type L colonies of
Proteus
were produced by inoculation of bacteria into media containing penicillin. The large bodies developing from the bacteria and the organisms in B-type L colonies of
Proteus
, like the parent bacteria, had a cell wall consisting of a plasma membrane and an outer cell wall. The loss of rigidity in the cell wall indicated an alteration in its structure. The A-type L cultures of
Proteus
consisted of irregular branching masses extending in several directions, of small dense organisms corresponding to the elementary corpuscles present in cultures of
Mycoplasma
, and of intermediary forms. In contrast to the B-type, all organisms in the A-type colonies were surrounded by a single unit membrane corresponding to the plasma membrane of bacteria. The structures inside the cell membrane, both in the A- and B-type, seemed to correspond to the structure of the parent bacteria, which contained ribosomes and threads of DNA. The elementary corpuscles formed chains and filaments, and, apparently, these corpuscles took part in the multiplication by gradual enlargement. The organisms seen in the cultures of all L forms and
Mycoplasma
studied, except in the B-type L forms of
Proteus
, corresponded in size, shape, and structure, as well as in the development of elementary corpuscles, to the organisms in the A-type L form of
Proteus
. In contrast to the spherical organisms usually seen in broth cultures, the organisms in young cultures of
Mycoplasma
, which were grown within the agar, were similar in morphology, as well as in the discernible structure of the organisms, to L forms. Significant morphological and structural differences were not apparent between the L forms and
Mycoplasma
(in cultures grown within agar media) under the conditions of this investigation.
Surface Structure of Yeast Protoplasts
Authors: Streiblová Eva
Published: January 2020

The fine structure of the yeast cell wall during protoplast formation was studied by means of phase-contrast microscopy and the freeze-etching technique. The freeze-etching results indicated that at least in some cases the entire wall substance was not removed from the surface of the protoplasts. After a treatment of 30 min to 3 hr with 2% snail enzymes, an innermost thin wall layer as well as remnants of the fibrillar middle layer sometimes could be demonstrated.
Cystathionine Metabolism in Methionine Auxotrophic and Wild-Type Strains of
Saccharomyces cerevisiae
Authors: Sorsoli W. A. , Buettner M. , Parks L. W.
Published: January 2020

The role of cystathionine in methionine biosynthesis in wild-type and auxotrophic strains of
Saccharomyces cerevisiae
was studied. Homocysteine and cysteinerequiring mutants were selected for detailed study. Exogenously supplied cystathionine, although actively transported by all strains tested, could not satisfy the organic sulfur requirements of the mutants. Cell-free extracts of the wild-type, homocysteine, and cysteine auxotrophs were shown to cleave cystathionine. Pyruvic acid and homocysteine were identified as teh products of this cleavage. A mutant containing an enzyme which could cleave cystathionine to homocysteine in cell-free experiments was unable to use cystathionine as a methionine precursor in the intact organisms. The significance of this finding is discussed.
Acetate-nonutilizing Mutants of
Neurospora crassa
I. Mutant Isolation, Complementation Studies, and Linkage Relationships
Authors: Flavell R. B. , Fincham J. R. S.
Published: January 2020

Sixty mutants of
Neurospora crassa
unable to grow on acetate as sole source of carbon, but able to utilize sucrose, were isolated. On the basis of complementation tests, they were divided into seven groups, each group representing a different gene. Six of the genes have been mapped; no two are closely linked. These loci have been designated
acu-1
to
acu-7
. Mutations at four of these loci result in poor germination of ascospores.
Mechanism of α-Glycerophosphate Regulation of Acetyl-Coenzyme A Carboxylase of
Saccharomyces cerevisiae
Authors: Rasmussen Roberta K. , Klein Harold P.
Published: January 2020

The mechanism proposed for the activation of animal acetyl-coenzyme A (CoA) carboxylase by α-glycerophosphate, namely, the removal of inhibitory palmityl-CoA via glyceride synthesis, is not the only possible one in the yeast system because extracts exhibiting marked stimulation of acetyl-CoA carboxylase activity by α-glyerophosphate show a lack of acyl-CoA compounds.
Origin of Cyanide in Cultures of a Psychrophilic Basidiomycete
Authors: Stevens Dennis L. , Strobel Gary A.
Published: January 2020

An unidentified psychrophilic basidiomycete used valine and isoleucine as precursors to hydrocyanic acid (HCN). As probable intermediates in the pathway from valine and isoleucine two cyanogenic glucosides, linamarin and lotaustralin, were demonstrated in fungus cultures. The fungus contained two β-glucosidases and an oxynitrilase which, acting together, were capable of releasing cyanide from both linamarin and lotaustralin. The two β-glucosidases were purified and compared as topH optimum, Michaelis constant, energy of activation, thermal stability, and substrate specificity. The products of methyl ethyl ketone cyanohydrin and acetone cyanohydrin dissociation by the oxynitrilase were demonstrated to be HCN together with methyl ethyl ketone and acetone, respectively. The oxynitrilase attacked aliphatic hydroxynitriles, but showed no activity on aromatic hydroxynitriles.
Hydrogen-oxidizing Methane Bacteria I. Cultivation and Methanogenesis
Authors: Bryant M. P. , McBride B. C. , Wolfe R. S.
Published: January 2020

A method for the mass culture of hydrogen-oxidizing methane bacteria has been developed; yields of 50 to 60 g (wet weight) of cells per 12 to 14 liters of culture medium were obtained. The methanogenic organism from the culture of
Methanobacillus omelianskii
was grown in a complex medium which was aerated with a gas mixture of hydrogen and carbon dioxide. Extracts prepared from hydrogen-grown cells formed methane from methyl cobalamin, 5-methyl tetrahydrofolate, serine, pyruvate, and carbon dioxide; these substrates have been shown to be precursors of methane in extracts of the ethyl alcohol-grown culture of
M. omelianskii
.
Pathogenicity and Neurological Effects of
Oidiodendron kalrai
for Mice
Authors: Tewari R. P. , Macpherson C. R.
Published: January 2020

An experimental infection was induced in mice by intravenous and intraperitoneal inoculation with
Oidiodendron kalrai
. The infected mice developed a complex neurological syndrome consisting of hyperirritability, jumping, circling, and ataxia, followed by coma and death or by apparent recovery. Visible lesions accompanied by inflammatory reaction and fungal elements were seen only in kidneys, but organisms were also identified in and isolated from the liver, spleen, lungs, and brain. Cortisone alone or in combination with streptomycin rendered the mice highly susceptible to infection with
O. kalrai
, and lesions were found in the brains as well as in the kidneys of these mice. Treatment of infected mice with streptomycin alone increased the severity and duration of the neurological syndrome, but such treatment did not increase the mortality rate.
Structure of the Cell Wall ofPythium debaryanum
Authors: Manocha M. S. , Colvin J. Ross
Published: January 2020

The structure of hyphal walls ofPythium debaryanumwas investigated by electron microscopy of shadowed replicas and thin sections, before and after digestion by snail gut enzymes or by 1nHCl at 100 C for 1 hr, and by X-ray diffraction. We found that the wall had two phases, one composed of microfibrils of unknown composition and a second consisting of an amorphous matrix, part of which stained like protein with potassium permanganate and part of which was removed by snail-gut enzymes. In the microfibrillar phase, there were two layers; an outer, thicker layer of randomly disposed microfibrils and an inner, thin layer of microfibrils oriented parallel to the hyphal axis. As inNeurospora crassa, the amorphous phase included a branching system of pores, 40–80 A in diameter. UnlikeN. crassa, the cytoplasm ofPythiumshowed Golgi bodies frequently, and many lomasomes were observed between the cytoplasmic membrane and the wall. The relations between these organelles and the mechanism of wall formation inPythiumare not understood.
Lysis of Yeast Cell Walls Induced by 2-Deoxyglucose at Their Sites of Glucan Synthesis
Authors: Johnson Byron F.
Published: January 2020

Six sites of 2-deoxyglucose (2DG)–induced lysis on three yeasts (
Schizosaccharomyces pombe, Pichia farinosa
, and
Saccharomyces cerevisiae
) coincided with the regions of growth of their glucan layers. Identification of the glucan layer as the site of lysis suggests a mechanism of attack by 2DG or by its derivatives. It is proposed that the glucan layer grows by addition of glucose into internal breaks of polysaccharide molecules. 2DG inhibited resynthesis (insertion of glucose) of the broken glycosidic linkage.
Isolation of
d
-Galacturonic Acid 1-Phosphate from Hydrolysates of Cell Wall Lipopolysaccharide Extracted from
Xanthomonas campestris
Authors: Volk Wesley A.
Published: January 2020

d
-Galacturonic acid 1-phosphate was found to be one of the products formed during hydrolysis of the cell wall lipopolysaccharide of
Xanthomonas campestris
in 0.01
n
acetic acid at
p
H 3.3. The molecule was shown to consist of equimolar amounts of
d
-galacturonic acid and phosphate. Resistance to borohydride reduction before, but not after, treatment with
Escherichia coli
alkaline phosphatase indicated that the phosphate group is attached to carbon-1 of the galacturonic acid. The presence of an additional phosphate group in the heteropolysaccharide of the cell wall lipopolysaccharide was also demonstrated. This phosphate group was considerably more resistant to acid hydrolysis than was the phosphate associated with the galacturonic acid. It is suggested that the more resistant phosphate is attached to either mannose or glucose, or to both.
Effects of Nigericin and Monactin on Cation Permeability of
Streptococcus faecalis
and Metabolic Capacities of Potassium-depleted Cells
Authors: Harold F. M. , Baarda J. R.
Published: January 2020

At a concentration of 10
−6
m
, nigericin and monactin inhibited growth of
Streptococcus faecalis
, and the inhibition was reversed by addition of excess K
+
. In the presence of certain antibiotics, the cells exhibited increased permeability to certain cations; internal Rb
+
was rapidly lost by exchange with external H
+
, K
+
Rb
+
, and, more slowly, with Na
+
and Li
+
. No effect was observed on the penetration of other small molecules. Cation exchanges induced by nigericin and monactin were metabolically passive and apparently did not involve the energy-dependent K
+
pump. When the cells were washed, the cytoplasmic membrane recovered its original impermeability to cations. By use of monactin, we prepared cells whose K
+
content had been completely replaced by other cations, and the metabolic characteristics of K
+
-depleted cells were studied. Cells containing only Na
+
glycolyzed almost as well as did normal ones and, under proper conditions, could accumulate amino acids and orthophosphate. These cells also incorporated
14
C-uracil into ribonucleic acid but incorporation of
14
C-leucine into protein was strictly dependent upon the addition of K
+
. When K
+
or Rb
+
was added to sodium-loaded cells undergoing glycolysis, these ions were accumulated by stoichiometric exchange for Na
+
. From concurrent measurements of the rate of glycolysis, it was calculated that one mole-pair of cations was exchanged for each mole of adenosine triphosphate produced.
Acetate Assimilation by
Nitrobacter agilis
in Relation to Its “Obligate Autotrophy”
Authors: Smith Arnold J. , Hoare Derek S.
Published: January 2020

Acetate (1 to 10 m
m
) had no effect on the rate of nitrite oxidation or exponential growth by
Nitrobacter agilis
. However, acetate-
1
-
14
C
and -
2
-
14
C
were both assimilated by growing cultures, and acetate carbon contributed 33 to 39% of newly synthesized cell carbon. Carbon from acetate was incorporated into all of the major cell constituents, including most of the amino acids of cell protein and poly-β-hydroxybutyrate (PHB). Cultures grown in the presence of acetate showed a significant increase in turbidity, attributable in part to protein synthesis and the accumulation of PHB in the “post-exponential phase,” when the supply of nitrite was completely exhausted. Cell suspensons of
N. agilis
assimilated acetate in the absence of bicarbonate and even in the absence of nitrite. However, the addition of nitrite increased the rate of acetate assimilation by cell suspensions. The distribution of
14
C-acetate incorporated by cell suspensions was qualitatively similar to that found with growing cultures. Cell suspensions of
N. agilis
slowly oxidized acetate to CO
2
. Addition of nitrite suppressed CO
2
production from acetate but increased the assimilation of acetate carbon into cell material.
N. agilis
contained all the enzymes of the tricarboxylic acid cycle. Growth of
N. agilis
in the presence of acetate did not significantly affect the levels of the enzymes of the tricarboxylic acid cycle, but did result in a 100-fold increase in the specific activity of isocitratase. In contrast, carboxydismutase was partially repressed.
N. agilis
was grown heterotrophically through seven transfers on a medium containing acetate and casein hydrolysate. The addition of nitrite increased the rate of heterotrophic growth. Heterotrophically grown organisms still retained their ability to grow autotrophically with nitrite. However, these organisms oxidized nitrite at a slower rate. Organisms from autotrophic and heterotrophic cultures were analyzed to determine the mean guanine plus cytosine content of their deoxyribonucleic acid; in both cases this mean was 61.2 ± 1%. We concluded that
N. agilis
is not an obligate autotroph; it appears to be a facultative autotroph which resembles the novel facultative autotroph,
Thiobacillus intermedius
, very closely.
Effect of Hydroxylysine on the Biosynthesis of Lysine in
Streptococcus faecalis
Authors: Gilboe Daniel P. , Friede John D. , Henderson L. M.
Published: January 2020

We were able to show that two lysine-independent mutants of
Streptococcus faecalis
ATCC 8043 contained the enzymes for the usual bacterial pathway for lysine biosynthesis. Because of this synthetic capacity, one mutant, the Lys
+
OHLys
s
strain, could not grow in the presence of hydroxylysine without a lysine supplement. Both lysine and hydroxylysine inhibited the first enzyme of the pathway, aspartokinase. Unlike the
Escherichia coli
enzyme,
S. faecalis
dihydrodipicolinic acid synthetase was not inhibited by either lysine or hydroxylysine. Both amino acids caused the repression of dihydrodipicolinic acid synthetase and diaminopimelic acid decarboxylase. Failure of Lys
+
OHLys
s
strain to grow in hydroxylysine-supplemented medium was caused by the mimicking of lysine control by hydroxylysine. Because hydroxylysine could not completely substitute for lysine and lysine could not be synthesized, the organism did not grow. We tested three lysine analogues and found that they prevented lysine-depletion lysis in the Lsy
−
OHLys
s
strain, as did hydroxylysine. Each analogue seemed to support cell wall mucopeptide synthesis, although ornithine did not. Preliminary data indicated that these analogues like hydroxylysine, have growth-inhibitory action on the Lys
+
OHLys
s
strain, but not the Lys
+
OHLys
r
strain. The nature of the specificity of the lysine-adding enzyme for cell wall mucopeptide synthesis is discussed.
Deoxyribonucleic Acid Homology in Bacterial Taxonomy: Effect of Incubation Temperature on Reaction Specificity
Authors: Johnson John L. , Ordal Erling J.
Published: January 2020

Parameters affecting deoxyribonucleic acid duplex (DNA-DNA) formation on membrane filters were evaluated. The reference strains used wereCytophaga succinicansstrain 8, which has a guanine plus cytosine (GC) content of 38%, andMyxococcus xanthusstrain FB, which has a GC content of 70%. Both organisms are gliding bacteria classified among the myxobacteria. Among the parameters evaluated, the incubation temperature used during duplex formation was found to be the most important in terms of the physical nature of the reaction product. When an incubation temperature 25 C below the melting point (Tm) of the native DNA was used, homologous duplexes exhibited a thermal stability similar to that of native DNA. At 35 C below the Tm, a considerable proportion of the duplexes were of much lower stability; at 40 C below the Tm, most of the duplexes were of much lower stability. Similar duplexes of low stability were also formed between DNA molecules from morphologically and nutritionally diverse organisms, provided the GC percentages of the DNA preparations were similar. Competition between unlabeled and labeled DNA fragments for binding sites on immobilized DNA was also greatly influenced by the incubation temperature. Heterologous DNA-DNA complexes exhibited thermal stabilities which correlated with measurements of DNA homology in experiments involving competition. In addition, the difference in thermal stabilities of heterologous and homologous DNA complexes (ΔT′m) may provide a measure of divergence in nucleotide sequences.
Murine Toxicity of
Agrobacterium tumefaciens
Authors: Hamilton Pat B. , Huisingh Donald
Published: January 2020

Eleven strains of the crown gall organism,
Agrobacterium tumefaciens
, tested by intraperitoneal injection into mice, were lethal within 48 hr. Five other species had some lethal strains. The lethal effect of
A. tumefaciens
appeared to be the result of a toxic rather than an infectious process, since histopathological anomalies were not found in mice injected with live cultures and since heat-killed cultures were lethal. The murine toxin disappeared when
A. tumefaciens
was grown at 36 C and reappeared when the organism was subsequently incubated below 30 C. The murine toxin itself was not inactivated by exposure to 100 C for 30 min. The toxin was associated with the cells and was not excreted into the medium. Centrifugal fractionation revealed that the toxin was associated with the smaller cells in 3-day stationary-phase cultures. These data suggested a possible relationship between toxin production and the production of the agents responsible for the initiation of plant tumors.
In Vivo–produced Anthrax Toxin
Authors: Fish Donald C. , Lincoln Ralph E.
Published: January 2020

Specific anthrax antigens were demonstrated in the blood of animals dying from anthrax. These antigens, which appear in the blood at the time when organisms are first detected and whose concentration continues to increase as the number of organisms increases, do not elicit a strong antibody response. The in vivo-produced toxin differs from the in vitro in killing more rapidly and being more difficult to detect. The in vivo toxin exists as an aggregate whose biological and serological activity depends upon its particular composition or configuration, or both.
Factors Affecting the Synthesis and Degradation of Ribulose-1,5-Diphosphate Carboxylase inHydrogenomonas facilisandHydrogenomonas eutropha
Authors: Kuehn Glenn D. , McFadden Bruce A.
Published: January 2020

Hydrogenomonas facilisandH. eutrophacultured in fructose medium retained high levels of ribulose-1,5-diphosphate carboxylase only when the following conditions were fulfilled: low aeration, FeCl3addition to fructose medium, and cell harvest at or prior to mid-exponential phase of growth. Repression of carboxylase synthesis was demonstrated under conditions of high oxygen tension during growth ofH. eutrophaon fructose. Upon depletion of fructose in the growth medium, carboxylase activity fell abruptly in both organisms. The decline could not be attributed to a repressive mechanism. Rapid inactivation of carboxylase was promoted by transfer of mid-exponential-phaseH. eutrophato a basal salts medium lacking fructose. During severe fructose starvation, N2, H2, 80% H2to 20% air, 2,4-dinitrophenol, actinomycin D, streptomycin, bicarbonate, and magnesium ion deficiency spared carboxylase. Nitrogen starvation or chloramphenicol afforded no protection during severe starvation. In vitro inactivation was also demonstrated in crude cell-free extracts from nonstarved, fructose-grownH. eutropha. Substrate bicarbonate protected against this loss. Inactivation of the carboxylase could not be demonstrated either by starvation of autotrophically grown cells or in autotrophic extracts. Autotrophic extracts mixed with heterotrophic extracts lost their carboxylase activity, but mixing with heterotrophic extracts that had been heated to 50 C resulted in no loss of activity. Mechanisms are proposed to accommodate these observations.
Aspects of Light Production by
Photobacterium fischeri
Authors: Kempner E. S. , Hanson F. E.
Published: January 2020

Studies of luminescence in growing cultures of
Photobacterium fischeri
revealed the characteristic kinetics of light emission, including a minimal phase of bacterial light output. A dialyzable substance present in the nutrient broth medium caused this transient inhibition in light production, although this substance did not affect culture growth. Experiments were carried out to determine the mechanism of action and the chemical properties of the inhibitor. The results suggest that the inhibitor may be binding directly to the luciferase molecules.
Quantitative Assay of Polysaccharide Components Obtained from Cell Wall Lipopolysaccharides of
Xanthomonas
Species
Authors: Volk Wesley A.
Published: January 2020

The cell wall lipopolysaccharides from 17 species belonging to the genus
Xanthomonas
were extracted from the cells with hot 45% phenol. After purification, the components of the polysaccharide were obtained by acid hydrolysis of the lipopolysaccharide and were quantitatively assayed. Data obtained show that all preparations contained uronic acid, phosphate, and mannose in molar ratios of approximately 1:2:1, and glucose and rhamnose in more variable concentrations. Most lipopolysaccharides contained either xylose or fucose, but those extracted from
X. sinensis
and
X. campestris
contained neither xylose nor fucose.
Selection of Temperature-sensitive Activating Enzyme Mutants in
Escherichia coli
Authors: Kaplan Samuel , Anderson Deborah
Published: January 2020

A method based on temperature-conditional resistance to thymineless death has been designed to facilitate the isolation of amino acid-activating enzyme mutants. This method may be modified to obtain a greater or lesser proportion of activating enzyme mutants. In the latter instance, an increased proportion of temperature-sensitive macromolecule mutants of other types is obtained. Additional uses of this procedure are discussed.
Effects of Meat-curing Salts and Temperature on Production of Staphylococcal Enterotoxin B
Authors: McLean Ruth A. , Lilly Helen D. , Alford John A.
Published: January 2020

We investigated the effect of time, temperature, and the presence of sodium chloride, nitrates, and nitrites in the medium on the growth and production of enterotoxin B by
Staphylococcus aureus
. Assays by the double gel-diffusion method showed that maximal enterotoxin B production occurs at the beginning of the stationary phase of growth. Lowering the temperature of incubation decreased the amount of toxin produced without affecting the total amount of growth. Increases in concentration of curing salts reduced toxin production more rapidly than cell growth. The relationship of these observations to food-poisoning outbreaks is briefly discussed.
Effect of Chloramphenicol on the Synthesis and Stability of Ribonucleic Acid in
Bacillus subtilis
Authors: Lazzarini Robert A. , Santangelo Edith
Published: January 2020

The effect of chloramphenicol on the synthesis and accumulation of ribonucleic acid (RNA) in
Bacillus subtilis
was studied. In the presence of chloramphenicol, transfer RNA and ribosomal RNA were synthesized as rapidly 2 to 3 hr after challenge as they were just prior to the addition of the antibiotic. However, under the same conditions, net RNA accumulation ceased after only 30 to 45 min. The failure to accumulate RNA after this time resulted from a rapid degradation of ribosomal RNA synthesized in the presence of chloramphenicol and a slow degradation of mature ribosomes. Since transfer RNA was not appreciably degraded, the ratio of transfer RNA to total RNA increased during the challenge.
Nuclear Fraction of
Bacillus subtilis
as a Template for Ribonucleic Acid Synthesis
Authors: Mizuno S. , Whiteley H. R.
Published: January 2020

A “nuclear fraction” prepared from
Bacillus subtilis
was a more efficient template than purified deoxyribonucleic acid for the synthesis of ribonucleic acid by exogenously added ribonucleic acid polymerase isolated from
B. subtilis
. The initial rate of synthesis with the nuclear fraction was higher and synthesis continued for several hours, yielding an amount of ribonucleic acid greater than the amount of deoxyribonucleic acid used as the template. The product was heterogenous in size, with a large portion exceeding 23
S
. When purified deoxyribonucleic acid was the template, a more limited synthesis was observed with a predominantly 7
S
product. However, the ribonucleic acids produced in vitro from these templates were very similar to each other and to in vivo synthesized ribonucleic acid as determined by the competition of ribonucleic acid from whole cells in the annealing of in vitro synthesized ribonucleic acids to deoxyribonucleic acid. Treatment of the nuclear fraction with heat (60 C for 15 min) or trypsin reduced the capacity of the nuclear fraction to synthesize ribonucleic acid to the level observed with purified deoxyribonucleic acid.
Immunological Studies on Dermatophytes II. Serological Reactivities of Mannans Prepared from Galactomannans I and II of
Microsporum quinckeanum, Trichophyton granulosum, Trichophyton interdigitale, Trichophyton rubrum
, and
Trichophyton schoenleinii
Authors: Grappel Sarah F. , Blank F. , Bishop C. T.
Published: January 2020

The contribution of terminal galactofuranose residues to the antigenic specificity and to cross-reactivity of galactomannans isolated from five species of dermatophytes,
Microsporum quinckeanum, Trichophyton granulosum, T. interdigitale, T. rubrum
, and
T. schoenleinii
, was investigated. Galactofuranose units were removed from galactomannans I and galactomannans II by mild acid hydrolysis. The resulting mannans were tested for serological reactivity with rabbit antiserum to
M. quinckeanum
by qualitative precipitation in gel and by quantitative complement-fixation analyses. Our results showed that, with this antiserum, the galactofuranose residues contributed greatly to the antigenic specificity and to cross-reactivity of the galactomannans II, but these residues were less significant as antigenic determinants in the galactomannans I. We have shown that mannans isolated from three
Candida
species reacted with rabbit antiserum to
M. quinckeanum
.
Development and Use of a Polyvalent Conjugate to Differentiate
Histoplasma capsulatum
and
Histoplasma duboisii
from Other Pathogens
Authors: Kaufman Leo , Blumer Sharon
Published: January 2020

Previous investigations have demonstrated the existence of five
Histoplasma capsulatum
serotypes. Available specific fluorescent-antibody reagents stain only four of the five serotypes. Antibodies produced against the most complete
H. capsulatum
serotype were labeled with fluorescein isothiocyanate to develop a reagent specific for
H. capsulatum
that was reactive with all the known serotypes. The unadsorbed reagent not only stained all the
H. capsulatum
serotypes, but it also stained cultures of
Blastomyces dermatitidis, H. duboisii
, several
Candida
species, and a variety of other fungi. Adsorption of the conjugate with antigens of
C. albicans
produced a reagent that intensely stained only
H. capsulatum, H. duboisii
, and
B. dermatitidis
. Differentiation of
B. dermatitidis
from the
Histoplasma
species was accomplished by application of a
B. dermatitidis
specific fluorescent antibody to antigens positive with the
H. capsulatum
reagent. At present, differentiation of
H. capsulatum
from
H. duboisii
may be accomplished only by animal inoculation. Our data substantiate the antigenic relationships hypothesized earlier, and they indicate that
H. capsulatum
shares at least two antigens with the other fungi that were studied.
Comparative Studies of Antigens from
Mycoplasma mycoides
and
Escherichia coli
Authors: Stone S. S. , Shifrine Moshe
Published: January 2020

Extracts of sonically disrupted
Mycoplasma mycoides
and
Escherichia coli
were fractionated by sucrose density gradient centrifugation. The presence of antigen in each of the fractions was determined by complement-fixation and agar-gel diffusion precipitin tests, in which cow, pig, and rabbit anti-
M. mycoides
sera and rabbit anti-
E. coli
serum were used. Fractions of
M. mycoides
, with a buoyant density of 1.225 or lower, fixed complement with cow and pig anti-
M. mycoides
sera. These fractions also formed precipitin lines with pig antiserum. Fractions in the buoyant density range of 1.10 to 1.20 fixed complement with rabbit anti-
E. coli
serum, but precipitin lines were not formed. All
E. coli
fractions fixed complement and gave precipitin lines with homologous serum. But fractions in the buoyant density range of 1.10 to 1.20 had minimal complement fixation with heterologous
M. mycoides
sera. The cross-reacting antigens in
M. mycoides
and
E. coli
had a buoyant density of 1.10 to 1.20; the specific antigens were isolated from
M. mycoides
at a buoyant density of 1.08 to 1.02.
Selection of
Escherichia coli
Mutants Lacking Glucose-6-Phosphate Dehydrogenase or Gluconate-6-Phosphate Dehydrogenase
Authors: Fraenkel D. G.
Published: January 2020

Glucose is metabolized in
Escherichia coli
chiefly via the phosphoglucose isomerase reaction; mutants lacking that enzyme grow slowly on glucose by using the hexose monophosphate shunt. When such a strain is further mutated so as to yield strains unable to grow at all on glucose or on glucose-6-phosphate, the secondary strains are found to lack also activity of glucose-6-phosphate dehydrogenase. The double mutants can be transduced back to glucose positivity; one class of transductants has normal phosphoglucose isomerase activity but no glucose-6-phosphate dehydrogenase. An analogous scheme has been used to select mutants lacking gluconate-6-phosphate dehydrogenase. Here the primary mutant lacks gluconate-6-phosphate dehydrase (an enzyme of the Enter-Doudoroff pathway) and grows slowly on gluconate; gluconate-negative mutants are selected from it. These mutants, lacking the nicotinamide dinucleotide phosphate-linked glucose-6-phosphate dehydrogenase or gluconate-6-phosphate dehydrogenase, grow on glucose at rates similar to the wild type. Thus, these enzymes are not essential for glucose metabolism in
E. coli
.
A New Serological Group (E) ofNeisseria meningitidis
Authors: Vedros Neylan A. , Ng James , Culver Garth
Published: January 2020

A new serological group of encapsulatedNeisseria meningitidis, tentatively classified as group E, produced halo precipitates with homologous antiserum. Group-specific complement-fixing antibodies were produced in rabbits by inoculation with lysed cells. The group E isolates are immunologically related to group C, as shown by precipitation and quantitative agglutination. Antisera to group E strains did not protect mice challenged with groups A, B, or C organisms. Until now, a comparison of group E strains with the X, Y, and Z strains of Slaterus has not been conducted.
Adenosine Triphosphatase in Isolated Membranes ofStaphylococcus aureus
Authors: Gross R. , Coles N. W.
Published: January 2020

The preparation of cytoplasmic membranes from suspensions ofStaphylococcus aureuslysed by an enzyme recently isolated in these laboratories is described. These membranes contained: protein, 34.4%; ribonucleic acid, 6.6%; lipids, 34.5%; and total phosphorus, 1.4%. Such membranes exhibited adenosine 5′-triphosphatase (E.C. 3.6.1.3) activity, liberating orthophosphate at an initial rate of 0.53 μmole per min per mg of protein under optimal conditions. The enzyme was Mg++-dependent and K+- or Na+-stimulated. Maximal activity was observed with a molar adenosine 5′-triphosphate (ATP) to Mg++ratio of 1. One mole of orthophosphate was liberated per mole of ATP; the other product of digestion was adenosine 5′-diphosphate. Inorganic pyrophosphate and the 5′-triphosphates of guanosine, uridine, and cytidine were also attacked by membrane preparations, but more slowly than ATP. Ouabain,p-chloromercuribenzoate, and 2,4-dinitrophenol did not alter adenosine triphosphatase activity, whereas both Atebrine and chlorpromazine were inhibitory.
Plasmid-linked Resistance to Inorganic Salts in
Staphylococcus aureus
Authors: Novick Richard P. , Roth Christine
Published: January 2020

The penicillinase plasmids, a series of extrachromosomal resistance factors in
Staphylococcus aureus
, were found to carry determinants of resistance to a series of inorganic ions as well as resistance to penicillin and, in some cases, erythromycin. Most of the ions involved were inhibitory but not lethal to the bacteria; the resistance markers conferred an increase in resistance by comparison with susceptible organisms of between 3- and 100-fold, depending on the ion involved. Separate genetic loci for resistance to arsenate, arsenite, lead, cadmium, mercuric, and bismuth ions were demonstrated. Resistance to antimony and resistance to zinc were also found but were not separated genetically from resistance to arsenite and cadmium, respectively. The ion resistance markers appeared to form a cluster on the plasmid, with no other known marker within it. Naturally occurring plasmids were observed that lacked one or more of these ion resistance markers, as well as penicillinase-negative strains that were resistant to one or more of the ions. The patterns of markers carried by these various strains may provide some understanding of the evolution of a plasmid linkage group.
Cross-Protection Against
Salmonella enteritidis
Infection in Mice
Authors: Collins Frank M.
Published: January 2020

Mice were vaccinated with six strains of
Salmonella
and two strains of
Escherichia coli
, as well as with
Pseudomonas aeruginosa, Proteus vulgaris
, and
Serratia marcescens
. The amount of in vivo growth of each organism was followed by viable counting techniques on organ homogenates. The vaccinated mice, along with unvaccinated controls, were challenged intravenously with 1,000
ld
50
of a streptomycin-resistant strain of
Salmonella enteritidis
. The ability of the vaccine to protect the mice against virulent challenge correlated with the ability of the strain to establish a persisting population in the liver and spleen. Enumeration of the liver and spleen populations in the challenged mice revealed that extensive growth of
S. enteritidis
occurred in animals which showed “protection,” as assessed by progressive mortality data. No evidence was obtained for a major role of humoral factors in the cross-protection against intravenous
S. enteritidis
challenge.
Identification of a Precursor Pool of Ribosome Protein inEscherichia coli
Authors: Santer Melvin , Ruebush Trenton K. , Van Brunt John , Oldmixon Eben , Hess Russell , Primakoff Paul , Palade Philip
Published: January 2020

Antibodies prepared against proteins from 50Sribosomes ofEscherichia colialso reacted with the supernatant proteins of a cell-free extract ofE. coliwhich was ribosome-free. A reaction of immunological identity (Ouchterlony tests) was demonstrated for one of these supernatant proteins and one protein found in 50Sribosomes. Isotope experiments involving a shift from14C-leucine medium to12C-leucine medium showed that these proteins are not formed by breakdown of ribosomes during the preparation of cell-free extracts, but instead represent a pool of ribosome protein which is utilized during growth. In shift experiments from14C-leucine to12C-leucine medium, the kinetics of disappearance of labeled supernatant ribosome proteins (as measured by reaction with antibody) indicated that half the pool is depleted in 0.1 generation time at 37 C in glucose-salts medium. The pool was also depleted under conditions of amino acid starvation of a “relaxed” strain which accumulated “relaxed” particles. Most, if not all, of the protein present in “relaxed” particles was derived from the pool. The pool represented about 3 to 4% of the total soluble proteins in the ribosome-free supernatant fluid of anE. coliextract.
Constitutive Penicillinase Formation in
Staphylococcus aureus
Owing to a Mutation Unlinked to the Penicillinase Plasmid
Authors: Cohen Sidney , Sweeney Helen M.
Published: January 2020

Previously described penicillinase-constitutive mutations in
Staphylococcus aureus
are caused by genetic lesions in a regulator gene (or genes) on the penicillinase plasmid in close linkage to the structural gene. This report describes a new class (R2
−
) of penicillinase-constitutive mutants of
S. aureus
unlinked to the plasmid. By transductional analysis, the penicillinase plasmids in these mutants were wild type. Wild-type plasmids transduced into penicillinase-negative (plasmid loss) derivatives of R2
−
mutants produced penicillinase constitutively in amounts comparable to a fully induced culture of the wild-type strain. Penicillinase production in R2
−
mutants was maximal at 30 to 32 C and was much reduced at 40 C.
Synthesis of Protein and Ribonucleic Acid in a Psychrophile at Normal and Restrictive Growth Temperatures
Authors: Malcolm Neil L.
Published: January 2020

A defined medium was capable of supporting the growth of a psychrophilic coccus over its growth temperature range, −4 to 25 C. A rapid loss of viability occurred when exponential cells were transferred to growth-restricting temperatures above 25 C. Comparative studies of the chemistry of exponential-phase cells and cells exposed to supermaximum temperature indicated that this loss of viability is not due to temperature-induced membrane damage, inhibition of respiration or energy metabolism, or depletion of intracellular reserves. Moribund and dead cell populations showed an elevated level of intracellular adenosine-5′-triphosphate and amino acids—a finding reflected in the reduced rate of amino acid synthesis during the recovery of heat-shocked cells—and also leakage of degraded ribonucleic acid products into the medium. Incorporation studies indicated that loss of viability at 30 C was correlated with inhibition of protein synthesis, followed later by inhibition of ribonucleic acid synthesis. Deoxyribonucleic acid synthesis was unaffected by temperature above the maximum.
Deoxyribonucleic Acid Degradation in
Bacillus subtilis
During Exposure to Actinomycin D
Authors: Farmer James L.
Published: January 2020

At high concentrations (10 μg/ml), actinomycin D inhibited deoxyribonucleic acid (DNA) synthesis in
Bacillus subtilis
. Inhibition occurred quickly (in less than 1 min) and was complete. In strain 23
thy his
, inhibition of DNA synthesis by actinomycin D was followed by partial degradation of one of the two daughter strands to acid-soluble products. Degradation began at the replication point and proceeded over a distance equal to about 12% of a chromosome in length. Actinomycin D played some essential part in degradation, since exposure of the cells to other treatments or agents which inhibit growth did not lead to the above result.
Autotrophic and Heterotrophic Metabolism of
Hydrogenomonas
I. Growth Yields and Patterns Under Dual Substrate Conditions
Authors: DeCicco B. T. , Stukus Philip E.
Published: January 2020

Auxotrophic mutants of
Hydrogenomonas eutropha
and
H. facilis
requiring utilizable amino acids were employed to demonstrate the simultaneous utilization of H
2
and an organic substrate for growth. The ratio of the cell yields under dual substrate conditions compared to heterotrophic conditions indicated the relative contributions of the autotrophic and heterotrophic systems to the growth of the organism. Wildtype
H. eutropha
grown under simultaneous conditions exhibited a dicyclic growth pattern, the first cycle representing either heterotrophic or simultaneous growth and the second cycle representing autotrophic growth. The duration of the changeover period was either very short with no plateau or long with a plateau up to 8 hr, depending upon the organic substrate. The growth rate under simultaneous conditions with some organic substrates was faster than either the autotrophic or heterotrophic rate, but was not the sum of the two rates. The data suggest that, in the presence of both organic and inorganic substrates, heterotrophic metabolism functions normally but autotrophic metabolism is partially repressed.
Activity of Microorganisms in Acid Mine Water I. Influence of Acid Water on Aerobic Heterotrophs of a Normal Stream
Authors: Tuttle Jon H. , Randles C. I. , Dugan P. R.
Published: January 2020

Comparison of microbial content of acid-contaminated and nonacid-contaminated streams from the same geographical area indicated that nonacid streams contained relatively low numbers of acid-tolerant heterotrophic microorganisms. The acid-tolerant aerobes survived when acid entered the stream and actually increased in number to about 2 × 10
3
per ml until the
p
H approached 3.0. The organisms then represented the heterotrophic aerobic microflora of the streams comprised of a mixture of mine drainage and nonacid water. A stream which was entirely acid drainage did not have a similar microflora. Most gram-positive aerobic and anaerobic bacteria died out very rapidly in acidic water, and they comprised a very small percentage of the microbial population of the streams examined. Iron- and sulfur-oxidizing autotrophic bacteria were present wherever mine water entered a stream system. The sulfur-oxidizing bacteria predominated over iron oxidizers. Ecological data from the field were verified by laboratory experiments designed to simulate stream conditions.
Effect of Anaerobiosis on Staphylococcal Nuclease Production
Authors: Fox J. Bradley , Holtman D. Frank
Published: January 2020

Five strains ofStaphylococcus aureuswere examined quantitatively for the production of nuclease under aerobic and anaerobic conditions. Hydrolysis of deoxyribonucleic acid and ribonucleic acid was detected by measuring the release of acidsoluble nucleotides spectrophotometrically. We found that the enzyme was produced anaerobically, as well as aerobically, and that anaerobiosis had no effect on production of this enzyme when other conditions, such aspH, were held constant.
Streptococcal Sialidase II. Kinetic and Immunological Studies of Sialidase Produced by Group K Streptococcus
Authors: Hayano Seiki , Tanaka Atsuko
Published: January 2020

Kinetic and immunological studies were carried out on the sialidase produced by strain 6646, group K streptococcus (K-sialidase). The
K
m
values of K-sialidase were 0.9 m
m
for sialyllactose and 0.17 m
m
for bovine submaxillary mucin. The antibody against K-sialidase was produced in rabbits immunized with this enzyme. An assay procedure for determination of the anti-K-sialidase activity in terms of reciprocal of the serum dilution corresponding to the 50% inhibition point is described. Anti-K-sialidase activity is widely distributed in human sera, but this has not yet been found to be correlated with streptococcal diseases, and no definite relationship was proved between the anti-K-sialidase titer and the anti-streptolysin O titer through this study. Anti-K-sialidase serum had no effect on
Vibrio cholerae
sialidase.
Ultraviolet Sensitivity Gene of
Escherichia coli
B
Authors: Donch John , Greenberg Joseph
Published: January 2020

The ultraviolet sensitivity gene of
Escherichia coli
B was introduced into a K-12 recipient by transduction with phage P1. The
uvs
gene of
E. coli
B is cotransducible with the
proC
locus of K-12, is closely linked to
tsx
, is not linked to
lacZ
, and only rarely to
purE
. The transductants are mucoid, filamentous on irradiation, and show plating-medium response. The order of markers is
lacZ proC tsx uvs purE
.
Hemoglobin and
Escherichia coli
, a Lethal Intraperitoneal Combination
Authors: Bornside George H. , Bouis Pierre J. , Cohn Isidore
Published: January 2020

Intraperitoneal injection into mice of approximately 8 × 10
6
washed cells of
Escherichia coli
suspended in a lysate of washed human red blood cells or an aqueous solution of crystalline hemoglobin was lethal.
E. coli
suspended in washed intact erythrocytes, whole blood, plasma, or saline was innocuous. Fractionation of non-hemoglobin proteins from hemoglobin in lysates showed that only hemoglobin promoted a lethal infection. Overwhelming intraperitoneal growth of
E. coli
was attained in about 12 hr in lethal infections. The polymorphonuclear leukocytic response was ineffective against this rapid growth. The lethal mechanism is hypothesized to center on a unique role for free hemoglobin in inhibiting peritoneal absorption and stimulating an intraperitoneal exudate which supports luxuriant bacterial growth. Death is attributed to a lethal intoxication from bacterial endotoxins. This role for hemoglobin involves neither enhanced bacterial virulence nor lowered host resistance, and it would be of importance not only in peritonitis but also in problems where hemolysis and infection coexist.
Detection by Hemagglutination of Antibodies to Group A and Group E Streptococci by the Use of
O
-Stearoyl Derivatives of Their Cell Wall Carbohydrate-grouping Antigens
Authors: Slade Hutton D. , Hammerling Ulrich
Published: January 2020

The streptococcal group A and group E cell wall polysaccharide antigens were extracted with trichloroacetic acid from the cell or cell wall and esterified with stearic acid. The stearoyl derivatives contained 5 to 8% (by weight) of the ester. Sheep or human red blood cells were sensitized with the esterified antigens and were shown to agglutinate in the presence of specific rabbit antisera. Sera from (i) children hospitalized with group A streptococcal respiratory disease and (ii) swine possessing group E streptococcal lymphadenitis were shown to possess antibody titers significantly higher than the controls. The use of the two esterified antigens as controls for each other established the specificity of the reaction in each case. The general shape of the antigen-antibody precipitin curves was not changed when the stearoyl antigens were used; however, the quantitative aspects differed markedly. Oligosaccharides which inhibit the normal antigen-antibody precipitin reaction did not inhibit the hemagglutination reaction. The adsorption of antisera with whole streptococcal cells reduced the hemagglutination titer in relation to the quantity of cells employed. Data are given on the (i) optimal concentration of stearoyl antigen for sensitization, (ii) time of adsorption of antigen to red cells, (iii) use of albumin as diluting fluid, and (iv) condition of red cells. Properties of the esterified antigens and the mechanism of the agglutination reaction are discussed. The results indicate that polysaccharide antigens of other bacteria may be esterified and employed in a similar manner.