bluuebunny/crossref_metadata_2025 huggingface dataset:
Involvement of Protein and Ribonucleic Acid in the Association of Deoxyribonucleic Acid with Other Cell Components of
Escherichia coli
Authors: Porter Bruce , Fraser Dorothy K.
Published: January 2020

Cells of
Escherichia coli
were labeled with precursors of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and protein, lysed with detergent, and examined by starch-block electrophoresis and CsCl density gradient centrifugation. A large amount of the DNA was seen to remain at positions of low electrophoretic mobility and light density along with tryptophan and arginine-containing proteins and some RNA. Addition of labeled, phenol-extracted DNA to unlabeled cells prior to lysis and electrophoresis showed that only a small amount of the DNA became associated during or after lysis. Sonic treatment of a lysate removed most of the DNA to a position of electrophoretic mobility and density similar to that of free DNA, whereas pronase and ribonuclease released only a part of the DNA. We concluded that binding of DNA to cell membranes or other cell components occurs in the cell prior to lysis and involves protein and probably a specific type of RNA.
Salmonellosis in Mice Infected with
Mycobacterium tuberculosis
BCG I. Role of Endotoxin in Infection
Authors: Senterfitt Vernon C. , Shands Joseph W.
Published: January 2020

In agreement with previous observations, mice dying of salmonellosis were found to have a relatively constant number of
Salmonella
cells in their carcasses (ca. 5 × 10
9
). This number was not the result of bacterial overgrowth in moribund animals and therefore appears to be related to lethality. Similar numbers of salmonellae were recovered from the carcasses of infected mice which had previously been rendered hyperreactive to endotoxin either by infection with
M. tuberculosis
BCG or by adrenalectomy. In BCG mice, desensitization to endotoxin did not occur during the infection and, therefore, at death these mice contained a number of bacteria which would be equivalent to 1,000
ld
50
of endotoxin. Although the number of bacteria recovered from normal mice is roughly equivalent to a lethal quantity of endotoxin, this is obviously not the case in hyperreactive mice. Therefore, the relationship between lethality and 5 × 10
9
salmonellae cannot be explained by their endotoxin content. Nevertheless, when hyperreactive BCG mice are challenged parenterally with
Salmonella
, the endotoxin content of the inoculum may markedly influence the course of the infection.
Nutritional Characteristics of the Atypical Mycobacteria
Authors: Hedgecock Loyd W.
Published: January 2020

The ability of
Mycobacterium kansasii
and groups II and III of the atypical mycobacteria to utilize oleic acid, as well as selected carbohydrates and other compounds, as sources of carbon for growth was compared with that of the H37Rv and H37Ra strains of
M. tuberculosis
. The highest rate of growth of all of the mycobacteria examined occurred in the medium containing oleic acid as the carbon source when single substrates were tested. The H37Ra strain of
M. tuberculosis
and all of the atypical mycobacteria examined, except the P-8 strain of
M. kansasii
, displayed a deficiency in ability to utilize glucose for growth. The deficiency was manifested as delayed appearance of growth, suboptimal growth, or complete inability to utilize the sugar. Variant substrains of organisms that possessed an enhanced ability to utilize glucose for growth were isolated from representative strains of
M. kansasii
and groups II and III atypical mycobacteria inoculated on modified Kirchner glucose-agar and incubated for an extended period of time.
Action of Steroidal Diamines on Active Transport and Permeability Properties of
Escherichia coli
Authors: Silver Simon , Levine Elaine
Published: January 2020

The steroidal diamine irehdiamine A (IDA) is a potent inhibitor of bacteriophage growth and macromolecular synthesis in
Escherichia coli
. By using radioactive
42
K and
14
C-thiomethylgalactoside (TMG), rapid effects of IDA and related steroids, both on the influx of potassium and TMG via their respective transport systems and on the efflux (leakage) of radioactivity from the treated cells, have been measured. IDA affects both the influx and efflux of
42
K at concentrations of steroid as low as 2 × 10
−5
m
. Because of the increased leakage, it is not possible to tell whether there is a direct effect reducing the rate of active transport of potassium. The primary diamine, IDA, and its bis-secondary, bis-tertiary, and bis-quaternary diamine analogues are decreasingly effective in altering cell permeability properties in the order 1° > 2° > 3° > 4°. The effects of IDA on potassium transport are mirrored by similar effects on the transport of TMG. Therefore, the action of IDA is on the cell membrane and not directly on one or another transport system. The effects of IDA on cell permeability can reasonably explain the inhibitory actions of the drugs on bacteriophage growth and cellular metabolism.
Extraction and Isolation of Individual Ribosomal Proteins from
Escherichia coli
Authors: Fogel Samuel , Sypherd Paul S.
Published: January 2020

We have described a new method for the quantitative separation of ribosomal proteins and ribosomal ribonucleic acid. A procedure for the preparation of individual ribosomal proteins by polyacrylamide gel electrophoresis is also described. By the use of gels with smaller pores, at least four of the electrophoretic components from the 30
S
ribosome can be split into additional protein fractions. By the methods described here, it is possible to isolate in high purity at least 15 different proteins from the 30
S
ribosome of
Escherichia coli
.
Dark Recovery Processes in
Escherichia coli
Irradiated with Ultraviolet Light I. Effect of
rec
−
Mutations on Liquid Holding Recovery
Authors: Ganesan Ann K. , Smith Kendric C.
Published: January 2020

We have examined various derivatives of
Escherichia coli
K-12 for liquid holding recovery, a type of recovery originally observed in
E. coli
B irradiated with ultraviolet light. Although most of the K-12 derivatives tested showed relatively little or no recovery under our conditions, four of the six independent
rec
−
mutants examined, those carrying
recA1, rec-12, recA13
, and
rec-56
, respectively, displayed marked recovery. These mutants are distinguished from
rec
+
strains by their increased sensitivity to ultraviolet radiation and decreased ability to undergo genetic recombination. Two of them have also been reported to release large amounts of their deoxyribonucleic acid as acid-soluble material, especially after irradiation. None of the three
uvr
−
mutants examined, containing
uvrA6, uvrB5
, or
uvrC34
, showed comparable liquid holding recovery. The one

rec
−
uvr
−

derivative tested, carrying
recA13
and
uvrA6
, did not appear to undergo liquid holding recovery, although
recA13 uvr
+
strains did. Genetic analysis of one strain, a
recA13
mutant, indicated that all the
rec
+
derivatives obtained from it by conjugation, transduction and reversion, had lost the property of showing liquid holding recovery. From these results, we conclude that in
E. coli
K-12 the expression of liquid holding recovery depends upon certain
rec
−
mutations.
Fermentation of Glucose, Lactose, Galactose, Mannitol, and Xylose by Bifidobacteria
Authors: de Vries Wytske , Stouthamer A. H.
Published: January 2020

For six strains of
Bifidobacterium bifidum
(
Lactobacillus bifidus
), fermentation balances of glucose, lactose, galactose, mannitol, and xylose were determined. Products formed were acetate,
l
(+)-lactate, ethyl alcohol, and formate.
l
(+)-Lactate dehydrogenase of all strains studied was found to have an absolute requirement for fructose-1,6-diphosphate. The phosphoroclastic enzyme could not be demonstrated in cell-free extracts. Cell suspensions fermented pyruvate to equimolar amounts of acetate and formate. Alcohol dehydrogenase was shown in cell-free extracts. Possible explanations have been suggested for the differences in fermentation balances found for different strains and carbon sources. By enzyme determinations, it was shown that bifidobacteria convert mannitol to fructose-6-phosphate by an inducible polyol dehydrogenase and fructokinase. For one strain of
B. bifidum
, molar growth yields of glucose, lactose, galactose, and mannitol were determined. The mean value of Y (ATP), calculated from molar growth yields and fermentation balances, was 11.3.
Relationship Between Protein and Ribonucleic Acid Synthesis During Outgrowth of Spores of
Bacillus cereus
Authors: Rodenberg S. , Steinberg W. , Piper J. , Nickerson K. , Vary J. , Epstein R. , Halvorson H. O.
Published: January 2020

The rate of protein and ribonucleic acid (RNA) synthesis was examined during the outgrowth of spores of
Bacillus cereus
T in a chemically defined medium. RNA synthesis started 2.5 min after the initiation of germination, and protein synthesis after 4 min. Addition of a complete amino acid supplement and uracil supported high rates of RNA and protein synthesis throughout outgrowth. To determine the relationship between the rate of protein (
k
) and RNA synthesis, the kinetics of formation of various classes of RNA were followed during outgrowth. Ribosomal RNA (rRNA) comprised a relatively constant fraction of the total RNA throughout outgrowth (71 to 78%). The classes of RNA synthesized during this period were determined by germinating spores in radioactive uracil and then at intervals following their stability to actinomycin D. Initially, labile RNA comprised the largest fraction of newly formed RNA (ΔRNA), and this proportion decreased during outgrowth. The ratio of
k
/rRNA or
k
/Δ stable RNA varied considerably during outgrowth, whereas the ratio of
k
/labile RNA remained constant. The data suggest that the rate of protein synthesis is not rigidly coupled to either total or newly synthesized rRNA (ribosomes) during the early stages of outgrowth.
Degradation of Uric Acid by Certain Aerobic Bacteria
Authors: Rouf M. A. , Lomprey Robert F.
Published: January 2020

We have isolated and identified nine cultures of aerobic bacteria capable of growing on an elective medium containing uric acid as the only source of carbon, nitrogen, and energy. Four of these cultures were identified as
Aerobacter aerogenes
, two as
Klebsiella pneumoniae
, and the remainder as
Serratia killiensis, Pseudomonas aeruginosa
, and
Bacillus
species. Another culture identified as
P. fluorescens
required both glucose and uric acid for growth. When 23 laboratory stock cultures were inoculated into the uric acid medium,
A. aerogenes, B. subtilis, Mycobacterium phlei, P. aeruginosa
, and
S. marcescens
were able to grow. These five cultures also grew when the uric acid was replaced with adenine, guanine, hypoxanthine, xanthine, or allantoin, but growth was poor. In all of these media, including the uric acid medium, addition of glucose along with the nitrogenous compounds yielded good growth. Induction experiments demonstrated that the ability of
A. aerogenes, K. pneumoniae, P. aeruginosa, P. fluorescens, S. kiliensis, S. marcescens, B. subtilis
, and
Bacillus
sp. to degrade uric acid is an induced property. Of these organisms, only
Bacillus
sp. accumulated a small amount of intracellular uric acid.
Electron Transport System of the Protoheme-requiring Anaerobe
Bacteroides melaninogenicus
Authors: Rizza Victor , Sinclair Peter R. , White David C. , Cuorant Paul R.
Published: January 2020

Protoheme is essential for the growth of some strains of
Bacteroides melaninogenicus
. At low concentrations in the growth medium, protoheme determines the doubling time, total cell yield, and amount of cytochrome per bacterium. At high protoheme concentrations, the doubling time, total cell yield, and amount of enzymatically reducible cytochrome appear to remain nearly constant, and protoheme is accumulated by the cell. The accumulated protoheme can support the growth of the bacterium for at least eight generations in a protoheme-free medium. When growth and cytochrome content are proportional during growth at low protoheme concentrations, the bacteria incorporate 10 to 20% of the total available protoheme into a membrane-bound respiratory system. This respiratory system includes cytochrome
c
, a carbon monoxide-binding pigment, and possibly flavoproteins. The pigments can be reversibly reduced by reduced nicotinamide adenine dinucleotide or endogenous metabolism and can be oxidized anaerobically by fumarate or by shaking in air. Electron transport is inhibited by 2-
n
-nonyl-4-hydroxy-quinoline-
N
-oxide.
Pyrogenic Principle of the Ribonucleic Acid from the Yeast
Candida utilis
Authors: Kanoh S. , Kohlhage H. , Siegert R.
Published: January 2020

Experiments were performed to characterize the pyrogenic principle of ribonucleic acid (RNA) from the yeast
Candida utilis
. It was shown that ribonuclease hydrolysis of the RNA does not lead to inactivation of the pyrogenicity. Pyrogenicity was, however, destroyed by treatment with sodium deoxycholate. On column chromatography with Biogel under sterile and pyrogen-free conditions, the pyrogenic principle of yeast RNA was eluted together with the RNA. After treatment of the RNA with ribonuclease, it was possible to separate the pyrogenic activity from the RNA (hydrolysis products) to a great extent. Column chromatography of
Escherichia coli
endotoxin showed that the endotoxin was eluted in the same fractions as the pyrogenic activity of yeast RNA. On the basis of the behavior of the pyrogen, it may very well be that the fever reaction is produced not by the nucleic acid but by pyrogenic contaminants of the RNA preparation.
Cell Wall Composition and Serological Reactivity of
Histoplasma capsulatum
Serotypes and Related Species
Authors: Pine Leo , Boone Clarence J.
Published: January 2020

The composition of the cell walls of strains of
Histoplasma capsulatum
that were reactive in the complement-fixation test and that reacted with fluorescein-tagged specific anti-
H. capsulatum
serum were compared with the cell walls of
H. capsulatum
and
Histoplasma duboisii
that did not react in these serological tests. The cell walls of the serologically reactive strains of
H. capsulatum
were much more susceptible to the action of proteinases and to chitinase than were the serologically nonreactive strains, but were less susceptible to hydrolysis by 3% NaOH or 2
n
H
2
SO
4
. The walls of the serologically reactive strains had higher chitin, amino acid, and hexosamine contents, but they were lower in a “lactic acid” component that was released by alkaline hydrolysis of the nonreactive strains. The cell walls of strains of
H. duboisii
were similar to the walls of the serologically nonreactive strains of
H. capsulatum
. Chemical analyses of the cell walls of the various strains clearly support the serological typing of
H. capsulatum
and
H. duboisii
strains reported by Kaufman and Blumer.
Interaction of Colicins with Bacterial Cells IV. Immunity Breakdown Studied with Colicins Ia and Ib
Authors: Levisohn Reuben , Konisky J. , Nomura M.
Published: January 2020

Colicinogenic cells are immune to the lethal effect of the colicin which they produce. In the presence of very high concentrations of colicin, however, colicinogenic cells are no longer immune to the homologous colicin. This phenomenon, immunity breakdown, was studied with colicins Ia and Ib. The biochemical effects of colicin Ib on
Escherichia coli
were studied with a standard noncolicinogenic strain. At multiplicities of about 10 or higher, colicin Ib inhibited incorporation of leucine into protein and incorporation of
32
P-inorganic phosphate into deoxyribonucleic acid and ribonucleic acid by more than 95%. Under the same conditions,
32
P incorporation into phospholipid and nucleotide fractions was inhibited only partially (about 80 and 60%, respectively). Inhibition of
32
P incorporation into the terminal phosphorus of adenosine triphosphate was also considerably less than that of macromolecular synthesis (50 to 60%).
32
P incorporation into the nonnucleotide organic phosphate fraction was not inhibited. Respiration was not affected. Colicin Ia showed the same biochemical effects as colicin Ib. A mutant of an Ib-colicinogenic
E. coli
strain selected for resistance to low concentrations of colicin Ia was shown to be resistant to high concentrations of homologous colicin Ib, whereas the parent Ib-colicinogenic strain is sensitive to high concentrations of colicin Ib. This mutant lost its specific receptors for colicin Ib. Moreover, the biochemical effects of high concentrations of colicin Ib on Ib-colicinogenic cells during immunity breakdown were similar to the effects found in sensitive cells exposed to low concentrations of the same colicin. It is concluded that the killing of colicinogenic cells in the presence of high concentrations of homologous colicin is indeed caused by the homologous colicin molecules.
Oxidative Degradation of Methyl Ketones II. Chemical Pathway for Degradation of 2-Tridecanone by
Pseudomonas multivorans
and
Pseudomonas aeruginosa
Authors: Forney F. W. , Markovetz A. J.
Published: January 2020

A new intermediate was identified in the 2-tridecanone pathway of
Pseudomonas multivorans
, formerly designated pseudomonad 4G-9. This intermediate, undecyl acetate, was isolated directly from growing cultures of the organism; the structure of the intermediate was determined by infrared spectroscopy and by gas-liquid chromatographic identification of its hydrolytic products. An amended pathway is presented that accounts for the conversion of 2-tridecanone to provide carbon and energy for growth. It was shown that all early intermediates in the pathway arise biologically and sequentially from their precursors. Studies with
P. aeruginosa
showed that this organism also degrades 2-tridecanone by the pathway characteristic of
P. multivorans
. Biochemical mechanisms of the pathway are discussed. Discovery of undecyl acetate confirms our earlier contention that the primary attack on methyl ketones by bacteria can be by subterminal oxidation.
Proflavine Uptake and Release in Sensitive and Resistant
Escherichia coli
Authors: Kushner D. J. , Khan S. R.
Published: January 2020

Both
Escherichia coli
B and a proflavine-resistant mutant,
E. coli
B/Pr, took up the same amounts of proflavine when suspended in buffer containing the dye. In growth media, however, sensitive cells took up more proflavine than did resistant cells. Adding growth media or any one of several constituents of these media, including amino acids, glycerol, pyruvic acid, and metabolizable sugars, to resistant cells that had taken up proflavine in buffer caused them to lose the dye, but had less or no effect on sensitive cells. Certian salts caused an equal release of proflavine from resistant and sensitive cells. Proflavine released from resistant cells by glucose was not changed chemically. The effects of temperature and metabolic inhibitors suggest that proflavine uptake is a passive process but that its release may be an active one, dependent on metabolism. Glucose had more effect on the proflavine binding of
E. coli
B grown in a minimal medium than on that of cells grown in a complex medium.
E. coli
B was less susceptible to proflavine when growing in a minimal medium. The effects of other synthetic media on proflavine susceptibility of
E. coli
B were also studied. Deoxyribonucleic acid and envelopes from sensitive and resistant cells bound the same amounts of proflavine, and no difference was seen in the site of dye binding when sensitive and resistant cells that had taken up proflavine in buffer were sonically broken and fractionated. The results suggest that sensitive and resistant cells are equally permeable to proflavine but differ in the ease with which metabolites cause them to release bound proflavine. So far, however, these differences do not account completely for the ability of resistant cells to grow in high proflavine concentrations.
Effects of Ionizing Radiation on Synchronous Cultures of
Escherichia coli
B/r
Authors: Clark D. Joseph
Published: January 2020

The sensitivity of
Escherichia coli
B/r to X-irradiation is correlated with the replication cycle of deoxyribonucleic acid (DNA). The sensitivity to X-irradiation in the wild type can be attributed to the presence of nuclear targets plus DNA repair mechanisms. The effects of nuclear targets are observed in the recombination-deficient (
rec
−) mutant B/r, but the sensitivity reflected by changes in the slope of killing curves is absent. A study of different growth conditions indicates that maximal resistance to X rays occurs toward the middle of the division cycle. Evidence is offered that branched chromosomes respond as one-hit targets to X-irradiation. The killing effects of heavy-ion bombardment on
E. coli
are due primarily to ionizing radiation.
Putrescine-mediated Degradation of Ribonucleic Acid in Chloramphenicol-treated
Escherichia coli
Authors: Boyle Stephen M. , Cohen Paul S.
Published: January 2020

Escherichia coli
treated with chloramphenicol (CM) accumulated ribonucleic acid (RNA) in the absence of protein synthesis. The accumulated RNA (CM-RNA) was largely ribosomal (23
S
and 16
S
) and soluble (4
S
). The stability of CM-RNA depended upon the incubation conditions following the removal of CM. Thus, conditions which allowed the complete recovery of cultures from CM inhibition resulted in only a 30% loss of CM-RNA. The addition of proflavine to recovering cultures, which prevented further RNA synthesis, also resulted in about 30 to 35% degradation of CM-RNA. However, when RNA synthesis was inhibited by starving the recovering cultures for the required amino acid, histidine, 55% of the CM-RNA was degraded. The decreased stability of CM-RNA in histidine-starved cultures appeared to be due specifically to the intracellular buildup of putrescine. Under the above conditions of incubation, that RNA which was stable sedimented in sucrose gradients as 23
S
, 16
S
, and 4
S
RNA. It is suggested that intracellular putrescine plays a role in the stability of ribosomal RNA accumulated during CM treatment.
Noninvolvement of Acyl Carrier Protein with Citrate Synthase and Malate Synthase
Authors: Marcus Stuart L. , Reeves Henry C. , Ajl Samuel J.
Published: January 2020

Acyl carrier protein (ACP coli) was isolated from commercially grown
Escherichia coli
B and was acetylated by chemical methods. Biological activity of the synthesized acetyl-ACP coli was checked in an in vitro fatty acid-synthesizing system isolated from
E. coli
B. Since acetyl-ACP is preferred over acetyl-coenzyme A (CoA) as a substrate in these reactions, the possibility that it may substitute for acetyl-CoA in biosynthetically and oxidatively important cellular pathways (glyoxylate and Krebs cycles, respectively) was examined. Acetyl-ACP was tested for substrate activity with the enzyme of each cycle which has been found to utilize acetyl-CoA. Crystalline citrate synthase (EC 4.1.3.7) of porcine origin (Calbiochem) was found to be inactive with acetyl-ACP coli, which acted neither as a substrate nor as an inhibitor in the presence of acetyl-CoA. Malate synthase (EC 4.1.3.2) of the acetate type was isolated from acetate-grown cells of a mutant of
E. coli
K-12 (VGD
3
H
5
) and was also found to be inactive with acetyl-ACP coli. The significance of these results and of the recent discovery of another phospho-pantetheine-containing protein are discussed.
Mode of Action of Melinacidin, an Inhibitor of Nicotinic Acid Biosynthesis
Authors: Reusser Fritz
Published: January 2020

Melinacidin, a new antibacterial agent, blocked the synthesis of nicotinic acid and its amide in
Bacillus subtilis
cells. The inhibitory activity of the agent was reversed by nicotinic acid, its amide, or nicotinamide adenine dinucleotides, but not by
l
-kynurenine,
l
-3-hydroxykynurenine,
l
-hydroxyanthranilic acid, or quinolinic acid. These properties indicated that the antibiotic interferes with the conversion of quinolinic acid to nicotinate ribonucleotide by the enzyme quinolinate phosphoribosyl-transferase. However, the activity of a purified preparation of this enzyme derived from a
Pseudomonas
strain was not impaired by the antibiotic. This suggested that, in
B. subtilis
, melinacidin interferes with a reaction which occurs before the formation of quinolinic acid in the biosynthetic pathway leading to nicotinic acid. Failure of quinolinic acid to reverse melinacidin inhibition in
B. subtilis
cultures might be due to insufficient penetration of the cell membranes by quinolinate.
Morphological Phenomena Associated with Penicillinase Induction and Secretion in
Bacillus licheniformis
Authors: Ghosh B. K. , Sargent M. G. , Lampen J. O.
Published: January 2020

Cells of uninduced
Bacillus licheniformis
(strain 749) in mid-logarithmic phase have no extensive intracytoplasmic membrane. After induction with cephalosporin C, characteristic organelles that contain tubules and vesicles with single-layered membranes and no visible internal substructure can be seen in thin sections in the periplasm. A magnoconstitutive penicillinase producer (749/C) contains similar structures. It is suggested that they represent a penicillinase secretory apparatus. In the first 15 min after induction, negatively stained preparations of induced 749 show large intracellular vesicles without individual contact with the cell surface. Negatively stained 749/C and fully induced 749 contain invaginations comparable to the structures seen in thin sections. When protoplasts of induced 749 and of 749/C are prepared, vesicles and tubules similar to those seen in thin sections of whole cells are liberated from the cell. Growing protoplasts of induced 749 show massive convolutions of the peripheral membrane, multiple layers of membrane, and characteristic long, slender tubules extending from the protoplast surface. These phenomena are not observed in uninduced 749 except for the production of a relatively small number of tubules. In 749/C, there were fewer convolutions than in induced 749, although tubule production was similar. Multiple layers of membrane were not observed in 749/C. The relation of the penicillinase secretory structures to mesosomes and to secretory structures of other organisms is discussed.
Localization of Cell-bound Penicillinase in
Bacillus licheniformis
Authors: Sargent M. G. , Ghosh B. K. , Lampen J. O.
Published: January 2020

When protoplasts are prepared from
Bacillus licheniformis
(strain 749/C, constitutive for penicillinase), approximately 60% of the cell-bound penicillinase is released. The remainder is retained by the protoplast and cannot be removed by washing. This release is specific, in that less than 7% of the cellular reduced nicotinamide adenine dinucleotide (NADH) dehydrogenase and α-glucosidase is liberated by the treatment. The freed penicillinase is excluded from G-200 Sephadex, and it is partially sedimented with a force of 65,000 ×
g
for 20 hr. It is probably attached to characteristic tubular and vesicular structures with single-layered membranes that are comparable to structures previously described in intact penicillinase-forming cells. The specific activity of the organelle is more than six times that of twice washed peripheral membrane; furthermore, about 8% of the protein of the structure is penicillinase. At substrate concentrations (benzylpenicillin) of about one-fifth the
K
m
value, whole cells show a slight permeability restriction, although this does not occur in isolated particles and protoplasts.
Electron Microscopic Observations on the Penetration of
Bdellovibrio bacteriovorus
into Gram-negative Bacterial Hosts
Authors: Burnham Jeffrey C. , Hashimoto T. , Conti S. F.
Published: January 2020

The progressive stages in
Bdellovibrio bacteriovorus
penetration into two strains of
Escherichia coli
were examined by use of electron microscopic techniques. The initial change observed in the ultrastructure of the host following parasitic attack was the swelling of the cell envelope at the site of attachment. The
Bdellovibrio
then appeared to pierce the center of this swelling, forming a pore in the outer wall layers of the host. The edges of this entry pore constricted the
Bdellovibrio
throughout its penetration into the host cell. Although partial disruption of the cytoplasmic membrane was always apparent, the parasite did not appear to actively penetrate through this barrier. An attempt is made to correlate the fine structural changes involved in penetration with the physiological data that have accumulated to date.
Relation of Mucoid Growth of
Staphylococcus aureus
to Clumping Factor Reaction, Morphology in Serum-Soft Agar, and Virulence
Authors: Yoshida Kosaku , Ekstedt Richard D.
Published: January 2020

The growth characteristics of several strains of
Staphylococcus aureus
in Brain Heart Infusion and in a modified Staphylococcus Medium No. 110 were compared. In the latter medium all of the strains studied showed an increased mucoid character. Some of the strains studied showed a greater potential to synthesize excess slime layer material than others. The highly mucoid strains grew as diffuse-type colonies in modified Staphylococcus Medium No. 110 serum-soft agar and reacted as though they were negative in the test for clumping factor. These strains were also found to be more virulent when used to challenge normal mice intraperitoneally.
Wild-Type Strain of
Staphylococcus aureus
Containing Two Genetic Linkage Groups for Penicillinase Production
Authors: Sweeney Helen M. , Cohen Sidney
Published: January 2020

Staphylococcus aureus
strain 55C1, isolated from a patient in 1955, contained two genetic linkage groups for penicillinase formation. One was linked to genes that control resistance to cadmium and mercuric ions; it had properties of a plasmidborne gene. The other was not linked to resistance to these metal ions; it had properties of a chromosomal gene. Penicillinase formation by cells that contained either linkage group was inducible by penicillins. Induced penicillinase in cells that contained both linkage groups equalled the sum of that produced in cells containing each group singly. Exopenicillinase produced by cells containing either gene was serological type A. Constitutive penicillinase formation resulting from regulator gene mutations in either linkage group was repressed to differing extents by a wild-type determinant in the
trans
position. The genetic structure and the regulation of penicillinase formation in strain 55C1 resembled in general those for penicillinase linkage groups which Asheshov and Dyke described for diploid mutant strains of
S. aureus
PS 80. There were differences in detail, however.
Effect of
p
-Fluorophenylalanine on Chromosome Replication in
Escherichia coli
Authors: Carpenter Carolyn , Binkley Stephen B.
Published: January 2020

The effect of
p
-fluorophenylalanine (FPA) on deoxyribonucleic acid (DNA) synthesis and chromosome replication was studied in a thymine-requiring mutant of
Escherichia coli
. The rate and extent of chromosome replication were followed by labeling the DNA with isotopic thymine and a density marker, bromouracil. The DNA was extracted and analyzed by CsCl gradient centrifugation. The block in chromosome replication caused by high concentrations of FPA occurred at the same point on the chromosome as that caused by amino acid starvation. In a random culture, DNA in cells treated with FPA replicated only slightly slower than the DNA from cells that were not exposed to the analogue. In cultures which had been previously starved for thymine, however, the DNA from the cells treated with FPA showed a marked decrease in the rate and extent of replication. It was concluded that the
E. coli
cell is most sensitive to FPA when a new cycle of chromosome replication is being initiated at the beginning of the chromosome.
Acute Granulomatous Response Produced in Mice by Trehalose-6,6-Dimycolate
Authors: Bekierkunst A.
Published: January 2020

Trehalose-6,6-dimycolate, a toxic lipid derived from tubercle bacilli, injected intravenously into mice in 10% emulsions of Bayol F caused a three- to fourfold increase in the weights of lungs compared with those of mice injected with emulsions of Bayol F alone or emulsions of Wax D. This change is due to a heavy infiltration of the lungs with granulocytes and large numbers of macrophages, with formation in some of the infiltrates of round foci, resembling granulomas.
Genetic Determination of Resistance to Acriflavine, Phenethyl Alcohol, and Sodium Dodecyl Sulfate in
Escherichia coli
Authors: Nakamura Hakobu
Published: January 2020

Wild-type strains of
Escherichia coli
K-12 are resistant to acriflavine. Gene
acrA
+
which determines resistance to acriflavine is located near the
lac
region of the chromosome. This gene determines not only resistance to basic dyes but also resistance to phenethyl alcohol. Acriflavine resistance was transmitted, together with phenethyl alcohol resistance, from a resistant Hfr strain to a sensitive recipient by mating. Reversion of the mutant gene
acrA1
(phenotypically acriflavine-sensitive) to acriflavine resistance was accompanied by a change from phenethyl alcohol sensitivity to resistance, and conversely the revertants selected for phenethyl alcohol resistance were resistant to acriflavine. A suppressor mutation,
sup-100
, closely linked to the
acr
locus, suppresses the
acrA1
gene (phenotypically acriflavine-resistant), but does not determine resistance to phenethyl alcohol and basic dyes other than acriflavine. The genetic change in the locus
acrA1
to types resistant to basic dyes and phenethyl alcohol was accompanied by an increase in resistance to sodium dodecyl sulfate, a potent solvent of lipopolysaccharide and lipoprotein. It is suggested that gene
acrA
determines synthesis of a membrane substance. The system seemed to be affected strongly by the presence of inorganic phosphate.
Genetic Control of the β-Ketoadipate Pathway in
Pseudomonas aeruginosa
Authors: Kemp M. B. , Hegeman G. D.
Published: January 2020

The regulation and genetic control of the β-ketoadipate pathway in
Pseudomonas aeruginosa
were investigated. The pattern of enzyme induction is apparently the same as in
P. putida
. Mutants were obtained for all but 1 of the 11 structural genes; the proximity of these genes on the chromosome was examined by transduction of the mutants with phage F116. If a group of enzymes was induced by the same compounds, the corresponding genes were closely clustered. Surprisingly, some locispecifying enzymes not sharing a common inducer were also clustered. It is suggested that this latter finding may indicate a degree of chromosomal specialization.
Shelf Life of Fluorescent Treponemal Antibody-Absorption Test Reagents
Authors: Roberts Merritt E. , Miller James N. , Pringle Thomas C. , Binnings Gerald F.
Published: January 2020

Properly prepared, standarized, and stored fluorescent treponemal antibody-absorption (FTA-ABS) reagents have been shown to have stabilities equal to other biological reagents. A liquid antigen over 10 years old has been shown to give a satisfactory reaction. Newer preparations have now been shown to be stable for over 5 years, and the tests on each are being continued. The very new liquid antigens which were originally standardized by the FTA-ABS method have shown no decrease in potency over a 20-month period. Stability studies on antigens dried on slides are now in their eighth month, with no apparent loss in potency. The stability of the conjugate is constant when stored frozen at −20 C or lyophilized. When stored as a liquid at 4 C, the stability is governed by the
p
H and the molarity of the buffer. The standardized and lyophilized sorbent has been shown to be stable for over 1 year.
Pyrimidine Nucleotide Metabolism and Pathways of Thymidine Triphosphate Biosynthesis in
Salmonella typhimurium
Authors: Neuhard Jan
Published: January 2020

The nucleoside triphosphate pools of two cytidine auxotrophic mutants of
Salmonella typhimurium
LT-2 were studied under different conditions of pyrimidine starvation. Both mutants, DP-45 and DP-55, are defective in cytidine deaminase and cytidine triphosphate (CTP) synthase. In addition, DP-55 has a requirement for uracil (uridine). Cytidine starvation of the mutants results in accumulation of high concentrations of uridine triphosphate (UTP) in the cells, while the pools of CTP and deoxy-CTP drop to undetectable levels within a few minutes. Addition of deoxycytidine to such cells does not restore the dCTP pool, indicating that
S. typhimurium
has no deoxycytidine kinase. From the kinetics of UTP accumulation during cytidine starvation, it is concluded that only cytidine nucleotides participate in the feedback regulation of de novo synthesis of UTP; both uridine and cytidine nucleotides participate in the regulation of UTP synthesis from exogenously supplied uracil or uridine. Uracil starvation of DP-55 in presence of cytidine results in extensive accumulation of CTP, suggesting that CTP does not regulate its own synthesis from exogenous cytidine. Analysis of the thymidine triphosphate (dTTP) pool of DP-55 labeled for several generations with
32
P-orthophosphate and
3
H-uracil in presence of
12
C-cytidine shows that only 20% of the dTTP pool is derived from uracil (via the methylation of deoxyuridine monophosphate); 80% is apparently synthesized from a cytidine nucleotide.
Varying Virulence in Rabbits Infected with Different Filamentous Types of
Histoplasma capsulatum
Authors: Daniels Lesley S. , Berliner Martha D. , Campbell Charlotte C.
Published: January 2020

Histoplasma capsulatum
filamentous primary isolates and their subcultures are separable into two distinct colonial types (A and B) having different microscopic characteristics. Yeast forms of the A and B types and the parent (P) strains from which they are derived are microscopically indistinguishable. Critically standardized inocula of living P, A, and B yeasts from one strain of
H. capsulatum
(G-184) were injected intravenously into 12 rabbits. Each type produced progressively debilitating disease, but in varying degrees. Of the 12 animals, 6 died within 2 to 14 weeks. A persisting copious nasal exudate, beginning at or before 1 week, was cultured weekly at 26 C on Mycosel (BBL) agar. Pure cultures of A and B filamentous type colonies were recovered from exudates of animals receiving A and B yeasts, respectively, whereas both filamentous types were isolated from rabbits injected with P yeasts, with B predominating. Only A and B yeasts thus maintained their filamentous integrity during animal passage. It was noted that dissemination of
H. capsulatum
through the nares of infected rabbits represents a possible hazard to laboratory personnel heretofore unrecognized. It is also a possible means of cross-infecting or sensitizing or cross-infecting and sensitizing animals housed in the same room, if A and B yeasts prove not to be antigenically identical.
Spore Germination in Strains of
Dictyostelium discoideum
and Other Members of the
Dictyosteliaceae
Authors: Cotter David A. , Raper Kenneth B.
Published: January 2020

Spores of all strains of
Dictyostelium discoideum
tested in this study germinated after a heat shock of 45 C for 30 min. Whereas the strains differed in their rates of germination, the rate for each strain was constant. A correlation existed between the rate of germination and the rate of vegetative growth when spores were inoculated into bacterial streaks. Heat shock clearly increased spore germination in
D. purpureum
, but the response was less dramatic than in
D. discoideum
. Enhancement also occurred in
D. rosarium
, but only in media containing peptone. Strains of
D. mucoroides
gave varied responses, and these could be divided into those which required mutrients for spore germination and those which did not. The spores of
Polysphondylium pallidum
were resistant to mild heat (45 C), but were not activated; peptone was required for germination. In contrast, the microcysts of this species were heat-labile and required no added nutrients for excystment.
Histidine and Aromatic Permeases of
Salmonella typhimurim
Authors: Ames Giovanna F. , Roth John R.
Published: January 2020

Mutants defective either in the histidine permease (
hisP
) or in the aromatic permease (
aroP
) were isolated in
Salmonella typhimurium
and were characterized. The
hisP
locus had a 49% linkage to
purF
by phage transduction. The
aroP
locus was close to
proA
. Merozygotes diploid for the
hisP
gene were constructed by episomal transfer, and
hisP
+
was dominant over
hisP
. The properties of merozygotes are described and discussed. A method for the selection of revertants of
hisP
mutants was devised. By this method, one of the
hisP
mutants was characterized as an amber mutant. The specificity of the aromatic permease was investigated by using as substrates analogues of the aromatic amino acids and of histidine.
Partial Exclusion of the
Nocardia erythropolis
Chromosome in Nocardial Recombinants
Authors: Adams James N.
Published: January 2020

Segregation of genes specifying nutritional requirements and inhibitor resistance was analyzed in recombinants from crosses of
Nocardia erythropolis
with
N. canicruria
. With all employed characters as both selecting and nonselecting markers, a single linear linkage group was depicted with genes in the following order;
leu-6 gly-4 purB2 tetA9 his-1 eryA7 strB2 ser-1 arg-1
. The relative frequency of crossovers between gene pairs was found to decrease as the map is read from
leu-6
to the right. The phenotype for
arg-1
was found infrequently in recombinants. This fact, coupled with the observed decrease in crossover frequency dependent upon map position, suggested two alternative explanations to account for the observed results. (i) Zygote formation among these nocardiae is a consequence of partial, oriented chromosome transfer from
N. erythropolis
to
N. canicruria
and is similar to the mechanism of polar transfer reported in matings of Hfr by F
−
Escherichia coli
. (ii) Being of diverse origin, the chromosomes of
N. erythropolis
and
N. canicruria
are not completely homologous, and decrease in crossover frequency dependent upon map position results from such chromosomal heterology. In this hypothesis, the infrequent occurrence of
arg-1
among recombinants is considered to be an artifact resulting from the action of a previously unrecognized suppressor gene for
arg-1
present in
N. canicruria
.
Homologies of Deoxyribonucleic Acids from
Brucella ovis
, Canine Abortion Organisms, and other
Brucella
Species
Authors: Hoyer Bill H. , McCullough Norman B.
Published: January 2020

The bacterium that causes canine abortion has polynucleotide sequences similar, in deoxyribonucleic acid (DNA)-DNA homology studies, to those of
Brucella suis
and, by inference from previous data, those of
B. abortus
and
B. melitensis
as well as
B. neotomae
. Therefore, the organism causing canine abortion appears to be a member of the genus
Brucella
. DNA preparations from
Serratia marcescens, Alcaligenes faecalis, and Bordetella bronchiseptica
, 58, 62, and 66 mole% guanine plus cytosine, respectively, do not have detectable polynucleotide sequence homologies with
B. suis
DNA which is 56 mole% guanine plus cytosine.
B. ovis
DNA lacks some of the polynucleotide sequences present in
B. suis
DNA and appears to be a deletion mutant. However, a large proportion of
B. ovis
polynucleotides are similar to those of other
Brucella
species, which supports the inclusion of
B. ovis
in the genus.
Autolytic Enzyme System of
Streptococcus faecalis
IV. Electron Microscopic Observations of Autolysin and Lysozyme Action
Authors: Shockman Gerald D. , Martin Joseph T.
Published: January 2020

Cell walls (LOG walls) were isolated from cultures of
Streptococcus faecalis
ATCC 9790 in the exponential phase of growth. These walls were either allowed to undergo autolytic dissolution (in the presence or absence of trypsin) or wall autolysis was inactivated with sodium dodecylsulfate (SDS walls). Inactivated walls were treated either with lysozyme or with isolated, partially purified
S. faecalis
autolysin. During wall lysis, samples were removed, negatively stained with phosphotungstate, and examined in the electron microscope. Both lysozyme and isolated autolysin appeared to act over the entire surface of SDS walls. After partial dissolution, a fibrous network over the surface was revealed. Lysozyme digestion revealed the presence of prominent, highly-contrasted equatorial and subequatorial bands around the walls. After trichloroacetic acid extraction, the bands were seen less frequently and less distinctly in the partially lysozyme digested walls, suggesting that the bands contained nonpeptidoglycan polymers. In the absence of trypsin (which activates a latent form of the autolysin), autolysis of LOG walls appeared to start at the equatorial bands and to proceed back towards the apex of the coccus. Ribbons of wall material coming off the wide edge of the nearly hemispherical wall fragments were observed. Activation of latent autolysis resulted in lytic action over the entire wall surface. The results are consistent with the previously postulated location of active autolysin at the areas of new wall synthesis and the random location of latent autolysin in LOG walls.
Bacteriocin (Hemolysin) of
Streptococcus zymogenes
Authors: Basinger Scott F. , Jackson Robert W.
Published: January 2020

The sensitivity of
Streptococcus faecalis
(ATTC 8043) to
S. zymogenes
X-14 bacteriocin depends greatly on its physiological age. Sensitivity decreases from the mid-log phase on and is completely lost in the stationary phase. The sensitivity of erythrocytes to the hemolytic capacity of the bacteriocin showed considerable species variation. The order of increasing sensitivity was goose < sheep < dog < horse < human < rabbit. However, when red cell stromata were used as inhibitors of hemolysis in a standard system employing rabbit erythrocytes the order of increasing effectiveness was sheep < rabbit < human < horse < goose. When rabbit cells were used in varying concentrations with a constant hemolysin concentration, there was a lag of about 30 min, which for a given hemolysin preparation was constant for all red cell concentrations. Furthermore, the rate of hemolysis increased with increasing red cell concentration. If red cells are held constant and lysin varied, the time to reach half-maximal lysis varies directly with lysin but is not strictly proportional. Bacterial membranes were one to three orders of magnitude more effective than red cell stromata as inhibitors. The order of increasing effectiveness seems to be
Escherichia coli < Bacillus megaterium < S. faecalis < Micrococcus lysodeikticus
. In addition to membranes, a
d
-alanine containing glycerol teichoic acid, trypsin in high concentration, and deoxyribonuclease also inhibited hemolysis. Ribonuclease,
d
-alanine,
l
-alanine,
dl
-alanyl-
dl
-alanine,
N
-acetyl-
d
-alanine,
N
-acetyl-
l
-alanine did not inhibit hemolysis.
Effect of Bacterial Endotoxin and Inhibitors on Tryptophan Oxygenase Induction in Mouse Liver Slices
Authors: Greene Joyce M. , Berry L. Joe
Published: January 2020

Tryptophan oxygenase activity in mouse liver slices maintained in cluture medium, in Krebs-Ringer bicarbonate solution, or in homologous whole blood declined within 3 hr to about one-half the original level. Actinomycin D and puromycin accelerated the rate of decline, but endotoxin did not. Direct addition of tryptophan to the medium resulted in a higher than normal tryptophan oxygenase activity within 1 hr, and this was maintained well above that of control liver slices up to 6 hr. Triamcinolone, at a dose that doubles tryptophan oxygenase activity in vivo, had no effect on the enzyme in liver slices. Actinomycin and endotoxin did not alter the substrate induction of tryptophan oxygenase; however, puromycin did, but to a limited extent. Liver slices prepared from mice 4 hr after an injection of cortisone had a greater tryptophan oxygenase activity than those of controls. Either endotoxin or actinomycin D resulted in a more rapid decline of the enzyme when added to the slices than was observed in the controls.