bluuebunny/crossref_metadata_2025 huggingface dataset:
Capsular Polysaccharide of
Clostridium perfringens
Hobbs 10
Authors: Lee Linda , Cherniak Robert
Published: January 2020

A capsular polysaccharide was isolated from a strain of
Clostridium perfringens
Hobbs 10 type A by cold-water extraction of whole, heavily encapsulated cells. The water-soluble polymer was isolated by alcohol precipitation and purified by treatment with chloroform-butanol, cetytrimethylammonium bromide, and column gel permeation chromatography by using Bio-Gel A-5m agarose. The formation of a single precipitin line, when the isolated polysaccharide was reacted with its homologous antisera by double diffusion in gel, was considered a criterion of immunochemical purity. The purified polymer appeared as a single peak when eluted from diethylaminoethyl-Sephadex with a linear gradient of NaCl. The polysaccharide was composed of glucose, galactose, galactosamine, and iduronic acid in a molar ratio of 4.1:5.1.7:1, respectively. These constituents accounted for 83% of the dry weight. The polysaccharide appeared to have a molecular weight of 40,000 and exhibited aggregation up to 120,000. A trace of peptide material could not be removed during purification.
Antibody Against
Clostridium perfringens
Type A Enterotoxin in Human Sera
Authors: Uemura Takashi , Genigeorgis Constantin , Riemann Hans P. , Franti Charles E.
Published: January 2020

Antibody against
Clostridium perfringens
type A enterotoxin was found in 82% of Brazilian and 65% of American serum samples.
Nonspecific Inhibition of Growth of Intracellular
Listeria monocytogenes
by Lymphocyte Culture Products
Authors: Jones Tobi , Youmans Guy P.
Published: January 2020

Supernatant fluids from mycobacteria-immune and mitogen-stimulated lymphocyte cultures were able to inhibit the intracellular growth of listeria in listeria-infected macrophages.
Association of Microorganisms with the Epithelium in the Alimentary Tract of
Aspicularis tetraptera
Authors: Tannock Gerald W. , Savage Dwayne C.
Published: January 2020

Parasitic nematode worms (
Aspicularis tetraptera
) were observed microscopically in histological sections of the colons of C57BL/6StCrl female mice. These nematodes have gram-positive bacteria intimately associated with the mucosal epithelium in their alimentary tract.
Decreased Susceptibility to
Listeria monocytogenes
in Mice After Infection with
Trichinella spiralis
Authors: Cypess R. H. , Lubiniecki A. S. , Swidwa D. M.
Published: January 2020

Mice challenged intravenously with
Listeria monocytogenes
at 7 or 21 days after
Trichinella spiralis
infection demonstrated a higher mean lethal dose and longer survival time than normal mice. This effect of helminthic infection was abrogated after 49 days.
Dissemination of Influenza Virus Between Anatomically Isolated Sites in Ferrets
Authors: Barber W. Henry , Small Parker A.
Published: January 2020

Influenza virus was shown to disseminate from the respiratory tract of nasally infected ferrets to a surgically formed, subcutaneous tracheal pouch. Conversely, ferrets infected via the pouch shed virus from the upper respiratory tract. These events occurred within the first 24 h after infection. Passively administered ferret antibody to virus did not prevent the dissemination.
Immunological Study of the Heat-Labile Enterotoxins of
Escherichia coli
and
Vibrio cholerae
Authors: Gyles Carlton L.
Published: January 2020

Immunodiffusion experiments were conducted to associate a precipitin line with
Escherichia coli
heat-labile enterotoxin (LT). Wild strains of porcine and of human enteropathogenic
E. coli
as well as laboratory-derived enterotoxigenic variants of
E. coli
K-12 were used for LT antigen preparations. These were produced mainly by ultrafiltration and ammonium sulfate precipitation of broth culture supernatants. When antisera with anti-LT activity were reacted with antigen preparations from Ent
+
and Ent
−
variants of
E. coli
K-12, a line “a” was given by Ent
+
but not by Ent
−
preparations. Line “a” was removed by absorption of anti-LT serum with antigen preparation from an Ent
+
E. coli
K-12, but was unaffected when the antigen preparation used to absorb the serum was from an Ent
−
E. coli
K-12. A line identical to “a” was given by antigen preparations from wild strains of porcine enteropathogenic
E. coli
reacted with homologous or heterologous anti-LT sera. One human strain of enteropathogenic
E. coli
was shown to possess an antigen identical to that which gave rise to line “a.” To demonstrate this line it was necessary to use high concentrations of gammaglobulin and high concentrations of the crude antigen preparations. LT preparations reacted with anticholera toxin to give a line “c,” which showed a reaction of partial identity with line “b” produced by reaction of pure choleragenoid and anticholera toxin. Lines “a” and “c” gave reactions of identity.
Mechanisms of Immunity in Typhus Infections IV. Failure of Chicken Embryo Cells in Culture to Restrict Growth of Antibody-Sensitized
Rickettsia prowazeki
Authors: Wisseman C. L. , Waddell A. D. , Walsh W. T.
Published: January 2020

Rickettsia prowazeki
, pretreated with typhus immune human serum, readily infects, and grows in, chicken embryo cells in culture. This finding is similar to those of previous studies which showed that typhus rickettsiae, pretreated with immune serum, grow in cells of the yolk sac of embryonated hen eggs and in the cells of the midgut of the human body louse. In contrast, identically treated typhus rickettsiae were destroyed by human macrophages in culture. Collectively, these observations seem to support an emerging concept that the fate of antibody-sensitized typhus rickettsiae depends upon the presence or absence of certain specialized properties of the host cell into which they gain entrance—nonphagocytic cells or “nonprofessional” phagocytic cells versus certain kinds of “professional” phagocytes. The phenomena involved probably have an important bearing on the mechanisms of the persisting infection and the nonsterile immunity which characterizes convalescence from typhus fever in man. They also form the basis for certain practical technical innovations in the laboratory.
Defects in the Immune System of Mice Infected with Lymphocytic Choriomeningitis Virus
Authors: Bro-Jørgensen K. , Volkert M.
Published: January 2020

Acute lymphocytic choriomeningitis virus infection of adult mice is associated with general immunosuppression, which develops during the 2nd week of the infection and persists for a period of 2 to 3 months. Studies of some cellular events in the immune system of infected mice brought to light a number of findings which seemed relevant to this immunosuppressive effect. Colony-forming stem cells, which may act as the precursors of the lymphoid cells, were temporarily inhibited during the first period of the infection. Presumably this inhibition also affected the thymus cells, which decreased dramatically at the same time. At a later stage of infection, defects developed within the population of immunocompetent cells, and this was most probably a consequence of the preceding suppression of the precursor cells. The defects in the immunocompetent cells were temporally related to the immunosuppression and seemed to be the ultimate cause of this phenomenon. At all events, antibody-forming cells were not damaged by the virus. In studies of neonatally infected baby mice, it was found that the development of immunological responsiveness was completely abolished for the first 2 weeks of life. It is therefore probable that the generation of immunocompetent cells was also affected in the babies. Evidence was obtained supporting the hypothesis that this effect played an important role for the induction of tolerance to the virus in the neonatally infected mice.
In Vitro Production of
N
-Nitrosodimethylamine and Other Amines by
Proteus
Species
Authors: Thacker L. , Brooks J. B.
Published: January 2020

N
-nitrosodimethylamine, a potent carcinogen, was produced by three strains each of
Proteus mirabilis, P. morganii
, and
P. rettgeri
, but not by three strains of
P. vulgaris
grown under the same conditions. Many of the alkaline-extractable volatile metabolites elaborated by these organisms are the same, but there are some qualitative and quantitative differences among species. Representative gas-liquid chromatographic profiles of the four species are presented, and the significance of the differences is discussed. Primary emphasis, however, is given to the importance of the production of
N
-nitrosodimethylamine by these microorganisms and the conditions under which it is produced.
Effect of Tetanolysin on Platelets and Lysosomes
Authors: Cox Claire B. , Hardegree Carolyn , Fornwald Ralph
Published: January 2020

Tetanolysin, partially purified, caused the lysis of human and rabbit platelets, as determined by a decrease in the optical density of platelet suspensions and the release of serotonin, enzymes, and protein. This lytic activity was neutralized by antitoxin. In addition, a suspension of the lysosome-containing large granule fraction of rabbit liver released hydrolytic enzymes when exposed to tetanolysin. Thus, tetanolysin can be added to the list of bacterial toxins that are lytic for a variety of cellular or subcellular membranes. These findings provide additional data that suggest that tetanolysin may contribute to the pathogenesis of some of the unusual manifestations observed in clinical tetanus.
Cytomegalovirus Interference In Vitro
Authors: Glasgow Lowell A.
Published: January 2020

Cytomegalovirus (CMV) was shown to induce a state of viral interference in human embryo fibroblast cultures (HEF). This interference was characterized by: (i) requirement for infectious virus; (ii) a latent period (48 to 96 h) for establishment of the interference; (iii) activity against a representative group of heterologous viruses; (iv) loss of interfering activity when challenged with a high multiplicity of infection; (v) lack of effect on adsorption of virus; (vi) mediation by a soluble product of CMV-cell interaction that it is not blocked by anti-CMV antibody; and (vii) absence of detectable interferon, although the soluble mediator shares a number of characteristics with interferon. This state of interference in HEF cultures could be simulated by extended exposure to subdetectable levels of human interferon. It is postulated that CMV induced the production of a soluble, interferon-like mediator of viral interference and that continuous exposure of the HEF culture to this mediator resulted in the development of resistance to a number of heterologous viruses.
Existence of Two Distinct Hemolysins in
Vibrio parahaemolyticus
Authors: Sakurai Jun , Matsuzaki Akiko , Takeda Yoshifumi , Miwatani Toshio
Published: January 2020

Two distinct hemolysins were demonstrated in
Vibrio parahaemolyticus.
A thermostable direct hemolysin purified from
V. parahemolyticus
WP-1, a Kanagawa phenomenon (KP)-positive strain, is antigenically different from a thermolabile hemolysin produced by
V. parahaemolyticus
T-3454, a KP-negative strain. The thermostable direct hemolysin was found in KP-positive strains but not in KP-negative strains. On the other hand, the thermolabile hemolysins were found in both KP-positive and -negative strains, although some KP-positive strains did not produce this hemolysin.
Experimental
Yersinia enterocolitica
infection in mice: Kinetics of growth
Authors: Carter Philip B. , Collins Frank M.
Published: January 2020

Infection of several strains of laboratory mice with a virulent strain of
Yersinia enterocolitica
was followed by performing viable bacterial counts on homogenates of selected tissues at intervals after intragastric, aerogenic, or intravenous infection. It is observed that CD-1 mice are more susceptible to
Y. enterocolitica
infection than either the C
57
B1/6 or B6D2 strains. Development of an enteric infection is dose dependent; less than 5 × 10
7
organisms by mouth yields sporadic, low levels of systemic infection, with many of the animals showing no apparent infection. Increasing the challenge inoculum by a factor of 10 eliminates the variability among the animals, giving rise to an enteric infection in all of the mice that moves quickly to the mesenteric lymph node. The bacterial population in the lymph node multiplies rapidly, and the infection is disseminated to the spleen, liver, and lungs, ultimately killing most of the animals. Exposure to an aerogenic challenge of less than 1,000 organisms resulted in a fulminating pneumonitis with an invariably fatal outcome. Intravenous challenge with 500 organisms caused a rapidly fatal, systemic infection. The growth of the bacteria in the intravenously infected mouse depends upon the temperature at which the challenge inoculum had been grown in vitro. At temperatures below 26 C, the bacteria are cleared from the blood at a slower rate and are more resistant to intracellular killing, as compared to organisms grown at 37 C. This effect results in the inoculum increasing to greater numbers in the tissues in a shorter period of time.
Respiratory Tract Cell-Mediated Immunity: Comparison of Primary and Secondary Response
Authors: Gadol N. , Johnson J. E. , Waldman R. H.
Published: January 2020

A secondary local and splenic cell-mediated immune response was observed and compared to the primary response. Previous studies have demonstrated cell-mediated immunity (CMI) by lymphocytes from bronchopulmonary washings and have shown that its appearance is to a large extent inedpendent of splenic CMI. This study evaluated the secondary as compared to the primary response, with respect to both cellular and humoral immune responses. Guinea pigs were immunized with influenza virus vaccine either nasally or parenterally, booster immunizations were given by the same route, and animals were killed at various times after immunization or booster. The inhibition of macrophage migration was used to assess CMI. As in previous studies, local application of antigen led to mainly local appearance of CMI, whereas parenteral immunization led to mainly systemic CMI. Both pulmonary and splenic lymphocytes showed an inhibition of macrophage migration that appeared 2 to 3 days sooner after the booster, as compared to the primary immunization. There was no evidence, however, for the earlier production or increased amount of antibody in the bronchial secretions in the boosted animals. The results suggest that pulmonary as well as splenic T lymphocytes exhibit memory, but that pulmonary B lymphocytes do not.
Effect of
Corynebacterium parvum
Treatment on the Growth of
Salmonella enteritidis
in Mice
Authors: Collins Frank M. , Scott Martin T.
Published: January 2020

The growth of
Salmonella enteritidis
in mice pretreated with 700 μg of killed
Corynebacterium parvum
was less than that seen in normal CD-1 mice. In treated mice, there was an early increased inactivation of the blood, liver, and spleen bacterial populations, followed by a prolonged period of slow but continuous bacterial growth. The treated mice failed to develop significant delayed hypersensitivity and did not show the characteristic antibacterial immune response seen in untreated infected animals. Eventually sufficient resistance did develop in most of the treated animals to protect them against the lethal effects of the challenge infection. The peak
C. parvum
effect was seen when
S. enteritidis
was injected 7 to 14 days later. Injection of
C. parvum
24 h after the bacterial challenge actually potentiated the
Salmonella
infection. There was no evidence of an increased specific humoral response by the
C. parvum
-treated mice, suggesting that the slower growth of the
S. enteritidis
was due to the continued enhanced killing of the bacterial population by the nonspecifically stimulated cells of the reticuloendothelial system, rather than to any specific augmentation of the host immune response.
Differential Attachment by Piliated and Nonpiliated
Neisseria gonorrhoeae
to Human Sperm
Authors: James-Holmquest Ann N. , Swanson John , Buchanan Thomas M. , Wende Reuben D. , Williams Robert P.
Published: January 2020

Piliated type 1
Neisseria gonorrhoeae
attached to 50% of human sperm after incubation of mixtures in vitro for 15 min at 35 C. In contrast, nonpiliated type 4
N. gonorrhoeae
attached to only 23% of sperm. Similar results were obtained with three different strains of
N. gonorrhoeae.
Treatment with heat or formaldehyde to kill bacteria did not affect the amount of attachment by piliated or nonpiliated types.
Escherichia coli
and
N. subflava
, other species of piliated bacteria, attached to about 40% of sperm, and the nonpiliated species
N. meningitidis
and
N. catarrhalis
attached to a comparable number of sperm, as did type 4
N. gonorrhoeae.
Prior incubation of type 1
N. gonorrhoeae
with purified antibody prepared against gonococcal pili reduced the percentage of sperm with attached bacteria to the same level as that for nonpiliated type 4 gonococci. Similar treatment of other piliated organisms or of nonpiliated
Neisseria
did not affect the attachment of the bacteria to sperm.
Deoxyribonucleic Acid Base Composition and Hybridization Studies on the Human Pathogen
Sporothrix schenckii
and
Ceratocystis
Species
Authors: Mendonça-Hagler Leda C. , Travassos L. R. , Lloyd K. O. , Phaff H. J.
Published: January 2020

Deoxyribonucleic acid (DNA) base composition, as measured by guanine plus cytosine (G + C) content, was determined in 17 strains of
Sporothrix schenckii
and
Ceratocystis
species. The average G + C content for
S. schenckii
was 54.7 ± 0.2 mol%. No strain of
Ceratocystis
, with the exception of
C. minor
, gave values for G + C content similar to those obtained for
S. schenckii
. All DNA samples from strains of
S. schenckii
cross-hybridized with high percentages of relative binding. DNA samples from
C. stenoceras
and
C. pilifera
showed low degrees of homology with
S. schenckii
DNA. The DNA from
C. minor
hybridized with 75% binding with that from a strain of
S. schenckii
, as compared with the homologous reaction.
Some Physiological and Biochemical Effects of a
Coxiella burneti
Lipopolysaccharide Preparation on Guinea Pigs
Authors: Baca O. G. , Paretsky D.
Published: January 2020

A lipopolysaccharide obtained in a dialyzed phenol extract from the rickettsia
Coxiella burneti
produced the following effects in guinea pigs after intraperitoneal injection: hyperthermia, loss of body weight, increased liver weight and concomitant lipid infiltration, elevated levels of hepatic and plasma cortisol, increased incorporation of [
3
H]orotic acid into hepatic 28
S
and 18
S
ribosomal ribonucleic acid, increased incorporation of
14
C-labeled amino acids into liver and plasma protein, and leukocytosis. Most of these events also occur during infection of guinea pigs with
C. burneti
, and a causal relationship between the rickettsial lipopolysaccharide and the biochemical changes that occur during Q fever is suggested.
Lectins Detecting Group C Streptococci
Authors: Ottensooser Fritz , Nakamizo Yasuzo , Sato Maroto , Miyamoto Yasushi , Takizawa Kinjiro
Published: January 2020

Lectin of
Wisteria floribunda
specifically agglutinates group C streptococci. The reaction is strongly inhibited by
N
-acetyl-
d
-galactosamine, slightly by lactose, and not at all by galactose. The utility of the simple test of the lectin with group C streptococci is discussed.
Effect of Ca
2+
on Morphology and Division of
Yersinia pestis
Authors: Hall P. J. , Yang G. C. H. , Little R. V. , Brubaker R. R.
Published: January 2020

Wild-type cells of
Yersinia pestis
are known to exhibit a nutritional requirement for physiological levels of Ca
2+
(∼2.5 mM) at 37 but not 26 C. Upon shift of Ca
2+
-deficient cultures from 26 (permissive condition) to 37 C (restrictive condition), bacterial mass quadrupled as the organisms doubled in number and then became elongated to about twice their normal size. As shown in thin sections, the resulting static cells contained axial filaments which differed from the typical irregularly lobate nucleoids of normal yersiniae grown under the permissive condition. Following prolonged cultivation under the restrictive condition (12 h), the organisms generally exhibited apparent degenerative changes, including separation or infolding of the cell wall and cytoplasmic membrane, degeneration of deoxyribonucleic acid, and appearance of vacuoles within the cytoplasm. At this time, the cells were unable to reinitiate cell division at 37 C upon addition of Ca
2+
but divided in partial synchrony after return to 26 C. This observation indicated that, at 37 C, continuous exposure to Ca
2+
is necessary for yersiniae to maintain normal morphology and the ability to divide.
Nicotinamide Adenine Dinucleotide and Nicotinamide Adenine Dinucleotide Phosphate-Linked Succinic Semialdehyde Dehydrogenases in a
Pseudomonas
Species
Authors: Padmanabhan R. , Tchen T. T.
Published: January 2020

A
Pseudomonas
species grown on polyamines was found to have the following enzymes that can dehydrogenate succinic semialdehyde: a constitutive nicotinamide adenine dinucleotide phosphate (NADP)-linked dehydrogenase, an inducible NAD-linked dehydrogenase specific for succinic semialdehyde (EC 1.2.lb), and more than one inducible NAD-linked aminoaldehyde dehydrogenase which can act on succinic semialdehyde, 3-aminopropanal, and 4-aminobutanal. These enzymes have been separated from each other by ammonium sulfate precipitation, column chromatography on diethylaminoethyl-Sephadex, and electrophoresis on polyacrylamide gel. The level of NAD-linked succinic semialdehyde dehydrogenase in cells grown on various C and N sources has been determined and found to be as expected of an inducible enzyme with, however, two slight variations: the basal level of the enzyme in cells grown on Casamino Acids is relatively high and readily detectable, and the level of this enzyme is the same when the cells are grown on γ-aminobutyrate with or without glucose and is, therefore, not subject to the classical glucose effect.
Mechanism of Optical Effects in Suspensions of a Marine Pseudomonad
Authors: Matula Tibor I. , Macleod Robert A.
Published: January 2020

When cells of a marine pseudomonad washed free of medium components with 0.05
m
MgSO
4
were suspended in solutions containing 200-m
m
concentrations of various salts, there was an immediate increase in optical density (OD), followed by a slow decrease. The decrease following the initial increase, but not the increase itself, could be prevented by omitting K
+
from or by adding metabolic inhibitors to the suspending solution. With NaCl, the initial increase in OD rose to a maximum as the salt concentration was increased to 200 m
m
and then declined at 500 m
m
. There was a corresponding decrease in intracellular fluid volume to a minimum at 200-m
m
NaCl and then a rise. When the increased OD produced by NaCl was maintained, the internal Na
+
and Cl
−
could be shown to have reached essentially the same concentration in the cells as in the medium. Thus, the OD changes could not have been due to osmotic effects. No evidence was obtained of a salt-induced aggregation of nuclear material. The OD of suspensions of isolated cell envelopes increased in response to increases in NaCl concentration in the absence but not in the presence of 0.05
m
MgSO
4
. The data was interpreted to indicate that the salt-induced increases in OD occurring in suspensions of the cells resulted from an interaction of salts with components of the cell envelope, causing contraction of the envelopes and shrinkage of the cells.
Nature of the
hisD3018
Frameshift Mutation in
Salmonella typhimurium
Authors: Yourno Joseph , Heath Susan
Published: January 2020

Histidinol dehydrogenase from three differing revertants of ICR-191A-induced frameshift
hisD3018
has been purified and examined for amino acid replacements. The enzyme from one spontaneously arising revertant, R7, contains an extra proline residue, whereas that from another, R5, contains an extensive frameshifted sequence, four amino acid residues of which have been identified to date. The amino acid replacement data are in agreement with the in vitro code word assignments and allow the characterization of the
hisD3018
frameshift as an addition of one nucleotide pair, most likely guanine plus cytosine. Enzymatic data for those ICR-191A-induced revertants of
hisD3018
arising within the
hisD
gene indicate that the enzyme is wild type and, therefore, that ICR-191A can cause deletions as well as additions of single base pairs. The wild-type amino acid sequence is restored in enzyme from an
N
-methyl-
N′
-nitro-
N
-nitrosoguanidine (NG)-induced revertant, R29, suggesting that NG is a base-deleting as well as a base-substituting mutagen. The unusual response of
hisD3018
to external suppressors is considered in terms of reinitiation of protein synthesis out of phase, coupled with suppression of a nonpermissive missense codon so generated, and of an alternative hypothesis invoking a true frameshift suppressor transfer ribonucleic acid with an extended or deleted anticodon.
Chemical Composition of
Azotobacter vinelandii
Cysts
Authors: Lin L. P. , Sadoff H. L.
Published: January 2020

Cysts of
Azotobacter vinelandii
ATCC 12837 were germinated by exposure to 3.0 m
m
ethylenediaminetetraacetic acid (EDTA)-tris(hydroxymethyl)aminomethane buffer at
p
H 7.8, and their outer coats (exines) were purified by differential and isopycnic centrifugation. Electron micrographs of exine showed it to consist of multilayers of a three-membered sheet structure whose thickness was 7.0 to 7.5 nm. The inner, less electron-dense layer (intine) was also prepared from cysts by EDTA treatment, centrifugation, concentration, and dialysis. The exine consisted of 32% carbohydrate, 28% protein, 30% lipid, and 3.2% ash, with the ash comprised of 1.62% calcium, 0.02% magnesium, and 0.34% phosphorus. The amino acid composition of exine was similar to that of gram-negative bacterial cell walls. The intine consisted of 44% carbohydrate, 9.1% protein, 37% lipid, and 4.1% ash, with the ash comprised of 2.45% calcium, 0.02% magnesium, and 0.38% phosphorus. The carbohydrates of both exine and intine contained glucose, mannose, xylose, and rhamnose. Glucosamine and galactosamine were found only in the exines. The fatty acids consisted of normal, iso, and anteiso saturated fatty acids with 10 to 18 carbon atoms and mono-unsaturated C
11
, C
16
, and C
18
fatty acids. The exines contained mostly bound lipid, but intines contained primarily free lipid.
Electron Microscopic Studies on Opaque Colony Variants of Group A Streptococci
Authors: Swanson John , McCarty Maclyn
Published: January 2020

Opaque colony variants of two strains of group A streptococci have been compared with blue colonies of the same strains by electron microscopy. In opaque colonies, the cocci are joined into elongated chains by exaggerated intercellular septa that often occupy the major portion of each cell's circumference. The thickness and lamination of cell walls in opaque colony variants are identical to those aspects of cell walls in blue colony forms. The similarity in cell wall architecture is found between opaque and blue forms whether or not M protein (and M associated surface fimbriae) is present. Extensive, direct contact between the nucleoid and the cytoplasmic membrane beneath intercellular septa is seen in opaque colony variants. The relationship of this marked nucleoid-cytoplasmic membrane association to the unusual chain forms in the opaque colony variants is unclear.
Pituitary Activation by Bacterial Endotoxins in the Rainbow Trout (
Salmo gairdneri
)
Authors: Wedemeyer Gary
Published: January 2020

Endotoxins from
Escherichia coli
and
Aeromonas salmonicida
caused marked cortisol production in the rainbow trout (
Salmo gairdneri
).
Early Stages of Conjugation in
Escherichia coli
Authors: Curtiss Roy , Caro Lucien G. , Allison David P. , Stallions Donald R.
Published: January 2020

We initiated these studies to learn more about the initial events during bacterial conjugation and to optimize conditions for their occurrence. We found that cells in donor cultures grown anaerobically prior to mating have (i) a higher mean number of F pili per cell, (ii) longer F pili, (iii) a higher probability of forming specific pairs with F
−
cells, and (iv) a faster rate of initiation of chromosome transfer than cells grown aerobically. The growth medium for the donor culture also influences these same parameters: a rich medium is superior to a completely synthetic medium. Starvation of donor cells in buffered saline or for a required amino acid results in (i) a loss of F pili, (ii) a loss in the ability of donor-specific phages to adsorb, (iii) a loss of ability to form specific pairs with F
−
cells and to yield recombinants, and (iv) an increase in recipient ability. These changes occur as a function of starvation time, and at rates which are dependent on the conditions of prior growth and starvation of the donor culture. Either treatment provides a rapid method for the production of F
−
phenocopies from donor cultures. Resynthesis of F pili by cells within a starved donor culture commences very soon after restoration of normal growth conditions, but full restoration of donor ability, as measured by recombinant yield, occurs at a slower rate. We found, along with other investigators, that F pili are essential for specific pair formation. We also found, however, that the presence of F pili is not sufficient for display of donor ability, nor is the absence of F pili enough for cells to exhibit recipient ability. This suggests, therefore, that one or more components, in addition to F pili, are necessary for the conversion of specific pairs to effective pairs (or for chromosome mobilization, or both) and for preventing donor cells from acting as recipients. On the basis of our results, we suggest optimal conditions for achieving high mating efficiencies.
Transformation ofPasteurella novicida
Authors: Tyeryar Franklin J. , Lawton William D.
Published: January 2020

Deoxyribonucleic acid from a streptomycin-resistant mutant ofPasteurella novicidatransformed portions ofP. novicidastreptomycin-sensitive populations to streptomycin-resistant. Similarly, mutants auxotrophic for tryptophan or purine biosynthesis were also transformed to nutritional independence.
Electron Microscopy of Effect of Polymyxin on
Escherichia coli
Lipopolysaccharide
Authors: Lopes J. , Inniss W. E.
Published: January 2020

Polymxyin treatment of isolated lipopolysaccharide from
Escherichia coli
resulted in the breakdown of its structure.
Second Pyridine Nucleotide-Independent
l
-α-Glycerophosphate Dehydrogenase in
Escherichia coli
K-12
Authors: Kistler W. S. , Hirsch C. A. , Cozzarelli N. R. , Lin E. C. C.
Published: January 2020

A soluble
l
-α-glycerophosphate dehydrogenase, which is stimulated by FAD and is independent of added pyridine nucleotides, functions during anaerobic catabolism of glycerol and
l
-α-glycerophosphate by
Escherichia coli
.
Mouse Virulence of K(L) Antigen-Containing Strains of
Escherichia coli
Authors: Wolberg G. , DeWitt C. W.
Published: January 2020

The mouse virulence of two K antigen-containing (L variety) strains of
Escherichia coli
(serotype O2:K1) isolated from human septicemia, and of their variants which lacked K antigen, was studied. The strains containing envelope antigen (K+) were highly virulent when injected intracerebrally or when suspended in mucin and injected intraperitoneally. After intraperitoneal injection of E-107 K+ (but not K−), there was a marked initial growth in the peritoneal cavity followed by bacteremia and infection of all the organs examined. In the mucin-enhanced lethal infection, this growth continued until death of the animal; in the nonlethal infection, growth ceased and the count dropped quickly after approximately 5 hr. Host defenses were depressed greatly by intraperitoneally, but not intravenously, administered mucin. Bacteria were most virulent when injected intraperitoneally. In vitro phagocytosis of the K+ bacteria required opsonins not needed for phagocytosis of the smooth K− variants. Opsonins were found in immunized rabbit and normal mouse sera. Immune rabbit sera contained antibodies with anti-K specificity which were opsonic in vitro and highly protective in vivo when administered passively. There appears to be a lesser anti-O opsonic and protective activity involving one of the strains (E-107 K+), and colonial morphology, agglutination, and absorption tests indicated a low amount of K antigen on this organism. No anti-O opsonic or protective activity could be shown involving the other strain (E-102 K+). When standard serological typing procedures were used, these two strains appeared to be identical serologically, but they differed greatly in sensitivity to immune rabbit serum in phagocytosis experiments in vitro.
Circular Deoxyribonucleic Acid from
Shigella dysenteriae
Y6R
Authors: Rush Mark G. , Gordon C. N. , Warner Robert C.
Published: January 2020

Circular deoxyribonucleic acid was isolated from
Shigella dysenteriae
Y6R and was found to consist of six species having molecular weights of 10
6
, 1.3 × 10
6
, 2.6 × 10
6
, 3.8 × 10
6
, 20 × 10
6
, and 24 × 10
6
daltons. These size classes were partially resolved by sucrose density gradient centrifugation. The minicircles (10
6
and 1.3 × 10
6
) were found to have a buoyant density in CsCl of 1.710 g/ml. The 3.8 × 10
6
dalton class had a density of 1.707 g/ml. The two largest species had a density of 1.702 g/ml. Two other strains,
S. sonnei
II and
S. dysenteriae
60, also contained circular deoxyribonucleic acid.
Phosphorylation and the Reduced Nicotinamide Adenine Dinucleotide Oxidase Reaction in
Streptococcus agalactiae
Authors: Mickelson M. N.
Published: January 2020

Cell-free extracts from aerobically grown
Streptococcus agalactiae
cells possess a reduced nicotinamide adenine dinucleotide (NADH) oxidase which is linked to oxygen. It is inhibited by cyanide, although cytochromes evidently are not involved. Adenosine triphosphate (ATP) formation occurs during the reaction, but 66 to 75% of the total ATP is formed nonoxidatively. The remaining 25 to 35% of the ATP formation is related to the oxidation of NADH. The formation of ATP in the oxidative reaction can be prevented by excluding oxygen or adding cyanide to prevent NADH oxidation. It can also be prevented by adding methylene blue or pyruvate, which bypasses electron transport to oxygen, but does not interfere with NADH oxidation. Potential sources of ATP, such as glycolysis, the pyruvate oxidase reaction, or the oxidative pentose cycle, are not present, and the high nonoxidative ATP formation is ascribed to the adenylate kinase reaction. The reaction requires adenosine diphosphate (ADP) as a phosphate acceptor. NADH oxidation is independent of ADP. Antimycin A, amytal, and 2,4-dinitrophenol decreased, but did not prevent, oxidative formation of ATP. P:O ratios ranged from 0.15 to 0.25. All of the oxidative activity was in the soluble portion of the cell-free extracts.
Enzymes of Intermediary Carbohydrate Metabolism in the Obligate Autotrophs
Thiobacillus thioparus
and
Thiobacillus neapolitanus
Authors: Johnson Emmett J. , Abraham S.
Published: January 2020

Levels of enzymes operative in the Embden-Meyerhof-Parnas (glycolytic) pathway, pentose phosphate cycle, citric acid cycle, and certain other phases of intermediary carbohydrate metabolism have been compared in
Thiobacillus thioparus
and
T. neapolitanus
. All enzymes of the glycolytic pathway except phosphofructokinase were demonstrated in both organisms. There were some striking quantitative differences between the two organisms with respect to the activities of the individual enzymes of the glycolytic pathway and the citric acid cycle. Qualitative differences were also found: the isocitrate dehydrogenase activity of
T. thioparus
is strictly nicotinamide adenine dinucleotide phosphate (NADP)-dependent, whereas that of
T. neapolitanus
is primarily nicotinamide adenine dinucleotide-dependent, activity with NADP being low; the glucose-6-phosphate dehydrogenase of
T. thioparus
is particulate, whereas that of
T. neapolitanus
is partly soluble and partly particulate; the 6-phosphogluconate dehydrogenase of
T. thioparus
is soluble, that of
T. neapolitanus
is partly soluble and partly particulate. All enzymes which function in the carbon reduction cycle were present at very high levels. In contrast, enzymes which operate exclusively in cycles other than the carbon reduction cycle were present at low levels. Of the enzymes not operative in the carbon reduction cycle that were examined, isocitric dehydrogenase had the highest specific activity. Both organisms possessed reduced nicotinamide adenine dinucleotide dehydrogenase activity. The qualitative and quantitative aspects of the data are discussed in relation to possible biochemical explanations of obligate autotrophy.
Biosynthesis of the Actinomycin Chromophore: Incorporation of 3-Hydroxy-4-Methylanthranilic Acid into Actinomycins by
Streptomyces antibioticus
Authors: Golub Ellis E. , Ward Martha A. , Nishimura Jonathan S.
Published: January 2020

Actinomycin synthesis by washed mycelia of
Streptomyces antibioticus
has been conducted in the presence of 3-hydroxy-4-methylanthranilate-(
carboxyl
-
14
C). Incorporation of this compound into actinomycins has been observed, which constitutes further evidence that 3-hydroxy-4-methylanthranilate is an intermediate in actinomycin biosynthesis. The position of the incorporated label has been determined to be within the actinomycin chromophore, and the label appears to be equally distributed between both halves of the chromophore. Incidental to these findings was the observation that the
14
C-labeled actinomycins were subject to rapid reabsorption by the organism with actinomycin V taken up preferentially to actinomycin IV.
Purification and Characterization of β-Glucosidase of
Alcaligenes faecalis
Authors: Han Y. W. , Srinivasan V. R.
Published: January 2020

A cellobiose-utilizing bacterium isolated from sugar cane bagasse and identified as a strain of
Alcaligenes faecalis
(ATCC 21400) produced an inducible β-glucoside-splitting enzyme. The enzyme was purified by a series of streptomycin and ammonium sulfate fractionations and by Sephadex and diethylaminoethyl column chromatography. The final preparation was purified 130-fold, with a recovery of about 10% of the initial enzyme activity. The enzyme had a wide
p
H range, with optimal activity at
p
H 6.0 to 7.0. The enzyme was stable in solution at
p
H 6.5 to 7.8 when kept at 30 C for 2 hr, but it was destroyed by temperatures above 55 C. At 58 and 60 C, the time required to inactivate 90% of the initial activity was 16 and 6.5 min, respectively. An activation energy of 9,500 cal/mole and a
K
m
of 1.25 × 10
−4
m
were obtained by using
p
-nitrophenyl β-glucoside as a substrate. The
K
i
value and hydrolysis of cellobiose by the enzyme indicated a high affinity of the enzyme for the cellobiose. The enzyme had its specificity on β-glucosidic linkage and the rate of hydrolisis of glucosides depended upon the nature of the aglycon moiety. The inactivation studies showed the presence of sulfhydryl groups in the enzyme. The activity of the enzyme was easily destroyed by the Cu
++
and Hg
++
ions. The Michaelis-Menton relationship and the rate of heat inactivation indicated the presence of one type of noninteracting active site in the bacterial β-glucosidase. Molecular weight of the enzyme was estimated by gel filtration (Sephadex G-200) and sucrose density gradient, and a value of 120,000 to 160,000 was obtained.
Pyrimidine Synthesis in
Neurospora crassa:
Regulation of Enzyme Activities
Authors: Caroline Dina F. , Davis Rowland H.
Published: January 2020

The regulation of several enzymes involved in pyrimidine biosynthesis in
Neurospora crassa
has been studied. Elevation of ATCase (
l
-aspartate carbamoyltransferase) activity is found in all pyrimidine-requiring mutants when they are starved for uridine. DHOase (dihydroorotase) is an unstable enzyme, and it is impossible to conclude what type of regulation, if any, controls this enzyme. DHOdehase (dihydroorotate dehydrogenase) activity shows a marked elevation in uridine-starved
pyr-2
cultures, a mutant blocked late in the pathway. Several mutants blocked early in the pathway show much smaller increases in DHOdehase activity and possible explanations for this are discussed. Differences in the modes of regulation of the pyrimidine biosynthetic pathways in various organisms are compared.
Induction of Myxospore Formation in
Stigmatella aurantiaca
(
Myxobacterales
) by Monovalent Cations
Authors: Reichenbach Hans , Dworkin Martin
Published: January 2020

Suspension cultures of
Stigmatella aurantiaca
can be induced to form myxospores by addition of the monovalent cations Li
+
, Na
+
, NH
4
+
, K
+
, or Rb
+
.
Fatty Acid Toxicity and Methyl Ketone Production in
Aspergillus niger
Authors: Lewis Harold L. , Darnall Dennis W.
Published: January 2020

Vegetative hyphae of
Aspergillus niger
rapidly converted caproic acid into 2-pentanone. More caproic acid was required for maximal ketone production at alkaline as compared to acidic
p
H values. Further increases in caproate concentrations at each
p
H value tested (4.5, 5.5, 6.5, 7.5, and 8.5) resulted in inhibition of ketone production and O
2
uptake. At alkaline
p
H values (8.5 and 7.5), oxygen uptake above the endogenous level and the production of 2-pentanone were parallel. This relationship did not hold at acidic
p
H values. At these
p
H values, ketone production continued (
p
H 6.5) or attained a maximum (
p
H 5.5 and 4.5) at caproate concentrations at which oxygen uptake was inhibited below endogenous levels. These data indicate that endogenous oxygen uptake was not inhibited by caproate at alkaline
p
H values at concentrations which did inhibit caproate oxidation and 2-pentanone production. Conversely, at acidic
p
H values, endogenous oxygen uptake was vigorously inhibited by caproate at concentrations at which exogenous fatty acid oxidation and 2-pentanone production were less affected. Simon-Beevers plots of these data showed that the undissociated acid was the permeant form of caproic acid. The fatty anion appeared to be the active or inhibitory form of caproate within the cell. Vegetative hyphae of
A. niger
were poorly buffered. Once the hyphae were washed and resuspended in phosphate buffer, they were well buffered towards inhibitory concentrations of caproic acid. These findings suggest that the primary mechanism(s) by which caproate inhibits oxygen uptake and ketone formation does not involve a change in the intracellular
p
H.
Correlation of Melting Temperature and Cesium Chloride Buoyant Density of Bacterial Deoxyribonucleic Acid
Authors: Mandel M. , Igambi Levi , Bergendahl Janet , Dodson M. L. , Scheltgen E.
Published: January 2020

Samples of bacterial deoxyribonucleic acid from bacteria having guanine plus cytosine (GC) contents in the range of 27 to 72 moles per cent GC were analyzed by optical melting (T
m
) and equilibrium buoyant density methods. The relation between these properties is shown to be linear. The relative value of 1.99 moles per cent GC per degree C change in T
m
is calculated, and a reference method for the calculation of GC contents relative to a standard is derived.
Ultraviolet-Induced Decrease in Integration of
Haemophilus influenzae
Transforming Deoxyribonucleic Acid in Sensitive and Resistant Cells
Authors: Muhammed Amir , Setlow Jane K.
Published: January 2020

The decrease in integration of transforming deoxyribonucleic acid (DNA) caused by ultraviolet irradiation of the DNA was found to be independent of the presence or absence of excision repair in the recipient cell. Much of the ultraviolet-induced inhibition of integration resulted from the presence in the transforming DNA of pyrimidine dimers, as judged by the photoreactivability of the inhibition with yeast photoreactivating enzyme. The inhibition of integration made only a small contribution to the inactivation of transforming ability of the DNA by ultraviolet radiation.
Nutritional Requirements for Growth and Yeastlike Development of
Mucor rouxii
Under Carbon Dioxide
Authors: Elmer Gary W. , Nickerson Walter J.
Published: January 2020

Unlike five other strains of
Mucor rouxii
previously studied, certain nutritional factors must be present for rapid growth and completely yeastlike development of
M. rouxii
(National Regional Research Laboratory 1894) under CO
2
; high CO
2
tensions markedly inhibit growth of this strain. Addition of yeast extract, peptone, or enzymatically hydrolyzed casein in substrate amounts to a basal medium (containing acid-hydrolyzed casein) completely relieved CO
2
inhibition of growth and permitted yeastlike development. The “CO
2
growth factor” activity of these supplements proved to be dialyzable and acid labile. These findings, together with the results of gel filtration and amino acid analysis, suggested that CO
2
growth factor activity can be attributed to small peptides.
Mycoplasma pneumoniae
and
Mycoplasma salivarium:
Electron Microscopy of Colony Growth in Agar
Authors: Knudson Dennis L. , MacLeod Roderick
Published: January 2020

Colonies of
Mycoplasma pneumoniae
and
Mycoplasma salivarium
grown in PPLO agar were examined by light and electron microscopy. The main objective of the investigation was to attempt in situ fixation and minimize tonic changes in the organisms. Microscopy revealed that both organisms grew both in and upon the agar. The agar and surface growths of
M. pneumoniae
exhibited similar profiles, whereas those of
M. salivarium
differed strikingly. Both organisms are highly pleomorphic, but their matrix was denser and appeared more intact than in previously reported profiles. Cells which resemble the commonly reported mycoplasma were occasionally observed. The significance of these discrepant profiles remains unanswered. It is suggested that they may represent aged or osmotically damaged cells.
Requirement of Polyamines for Bacterial Division
Authors: Inouye Masayori , Pardee Arthur B.
Published: January 2020

Synchronous cell division in an arginine auxotroph and a histidine auxotroph of
Escherichia coli
was obtained after starving for the required amino acid for 1 hr. However, cell division was not synchronized after starvation for 1 hr in another arginine auxotroph. This difference is proposed to depend on differences in the concentrations of polyamines in the cells. During amino acid starvation the ratio of putrescine concentration to spermidine concentration decreased in all strains, but it recovered afterward more rapidly in the third strain than in the other two. The cells divided when the ratio returned to normal in the Arg
−
mutants. Added putrescine permitted some of the cells of the first two mutants to divide sooner after amino acid starvation and thus eliminated synchrony. Spermidine added alone had no effect, but, when it was added together with putrescine, it restored synchronous division. Synchrony was established in the third mutant by adding spermidine after arginine starvation. Thus, both the variations in polyamine content and the effects of added polyamines suggest that the polyamines are essential in permitting cell division. We suggest that the molar ratio of putrescine to spermidine can be a critical factor for cell division. This effect of polyamines seems to be specific for cell division. Amino acid starvation does not induce delays in subsequent mass increase or deoxyribonucleic acid synthesis. Possible mechanisms of polyamine action are discussed.
Elongation of Fatty Acids in
Mycobacterium tuberculosis
Authors: Wang Lynn , Kusaka Takashi , Goldman Dexter S.
Published: January 2020

Cell-free extracts of the H37Ra strain of
Mycobacterium tuberculosis
contain a soluble enzyme system which catalyzes an elongation reaction of long-chain fatty acids. The predominant reaction involves the addition of a single C
2
unit to the acceptor fatty acid; the elongation takes place exclusively at the carboxyl end of the acceptor molecule. The endogenous acceptor lipid can be removed by solvent extraction of the enzyme system. The lipid-depleted enzyme can be fully reactivated with external acyl coenzyme A, after which elongation with acetyl coenzyme A takes place. The elongation reaction is avidin-insensitive and does not require adenosine triphosphate. Reduced nicotinamide adenine dinucleotide is the source of reducing equivalent, whereas reduced nicotinamide adenine dinucleotide phosphate is without effect.