bluuebunny/crossref_metadata_2025 huggingface dataset:
Natural Antibody in Mammalian Serum Reacting with an Antigen in Some Leptospires
Authors: Faine S. , Carter J. N.
Published: January 2020

Serum from normal mammals agglutinated and immobilized nonpathogenicLeptospira biflexaand agglutinated avirulent lines of pathogenic serotypesL. icterohaemorrhagiaeandL. zanoni. Virulent lines ofL. icterohaemorrhagiaeandL. zanoniwere not affected, nor were any of three strains ofL. pomona, one of which was avirulent. The active principle in serum was a β-macroglobulin which was heat-labile and reduced by 2-mercaptoethanol, and acted in conjunction with complement and lysozyme; it was absorbable from serum by Formalin-treated susceptible leptospires. The Formalin-stable receptor antigen, named “Z antigen,” is associated with virulence rather than pathogenicity, but may not be a determinant of virulence.
Inhibition of Bacterial Conjugation by Ribonucleic Acid and Deoxyribonucleic Acid Male-Specific Bacteriophages
Authors: Novotny Charles , Knight William S. , Brinton Charles C.
Published: January 2020

Both deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) male-specific phages, with an F-specific host range, inhibited the bacterial mating process of
Escherichia coli
. DNA phages prevented the formation of mating pairs but had no effect on mating pairs once they were formed. A step in RNA phage infection, prior to RNA penetration, prevented the formation of mating pairs and, in addition, prevented a fraction of existing mating pairs from completing the mating process. These findings are compatible with the hypothesis that donor cells have a single surface structure involved in both conjugation and male-phage adsorption and that this element is the F pilus.
Microcycle Sporogenesis of
Bacillus cereus
in a Chemically Defined Medium
Authors: MacKechnie Ian , Hanson Richard S.
Published: January 2020

A chemically defined medium which allowed germination, outgrowth, and subsequent resporulation of
Bacillus cereus
T spores, without intervening cell division (microcycle sporogenesis), is described. No medium replacement was required. The second-stage spores were heat-stable and had similar germination characteristics and dipicolinic acid content to primary spores. Deoxyribonucleic acid (DNA) replication began soon after germination and there was a doubling in the DNA content of the cells within 2 hr.
Itoic Acid Synthesis in
Bacillus subtilis
Authors: Peters W. J. , Warren R. A. J.
Published: January 2020

Under conditions of iron deficiency, strains of
Bacillus subtilis
produced 2,3-dihydroxybenzoic acid (DHB), 2,3-dihydroxybenzolyglycine (DHBG), or both of these compounds. DHB(G) production [production of DHB(G) refers to the production of DHB, or DHBG, or both] was proportional to the amount of iron present and occurred logarithmically, paralleling growth. Supplementation of media with more than 150 μg of iron per liter at zero-time inhibited DHB accumulation completely. In the presence of DHB, lower levels of iron inhibited DHB(G) production, so that the actual inhibitor of synthesis may involve the Fe
3+
:[DHB(G)]
3
complex. The strains producing DHBG also produced coproporphyrin III during iron-deficient growth, whereas a strain producing DHB did not produce coproporphyrin III under these conditions. Accumulation of DHB(G) was influenced by the levels of aromatic amino acids and anthranilic acid in the medium. In vivo experiments with strain B-1471 demonstrated that DHB was coupled to added glycine to form DHBG. Metabolism of DHB(G) was observed in two of the strains studied.
Separation of β-Factor Synthesis from Stimulated β-Carotene Synthesis in Mated Cultures ofBlakeslea trispora
Authors: Sutter Richard P. , Rafelson Max E.
Published: January 2020

Mated cultures ofBlakeslea trispora, grown in a potato extract-glucose-thiamine medium, produced 10 to 15 times more β-carotene than either unmated culture. Mated, but not unmated, cultures produced a family of compounds (β factor) which stimulated carotenogenesis in unmated cultures. In fact, carotenogenesis was stimulated sixfold more inminuscultures than inpluscultures. By altering the relative amounts ofplusandminusinocula used in fermentations of mated cultures, it was possible to separate the synthesis of β factor from the synthesis of extra β-carotene. Theplusstrain appeared to produce the β factor; theminusstrain appeared to produce most of the extra β-carotene. Kinetic studies of β-factor formation suggested that physical contact between the two strains may be required to initiate β-factor synthesis.
Initiation of the Germination ofBacillus subtilisSpores by a Combination of Compounds in Place ofl-Alanine
Authors: Wax Richard , Freese Ernst
Published: January 2020

l-Alanine initiates the germination of spores ofBacillus subtilisby entering two metabolic pathways. The products of one pathway, which is inhibited byd-alanine or by elevated temperature, can also be derived from a combination of fructose, glucose, and K+. The present study demonstrated that the products of the other pathway can be derived froml-asparagine orl-glutamine or, to a lesser extent, from several other amino acids. Hence, the combination ofl-asparagine (orl-glutamine), fructose, glucose, and K+can initiate spore germination in the absence ofl-alanine. Spores preincubated in a combination of asparagine and fructose do not lose refractility, optical density, or heat resistance, and do not take up methylene blue stain. The spores do, however, undergo some reaction which prepares them for a more rapid response to the later addition of glucose and K+. This preincubation reaction has an optimal temperature of about 44 C.
Accumulation of Tetracyclines by
Escherichia coli
Authors: De Zeeuw John R.
Published: January 2020

The net accumulation of tetracyclines by
Escherichia coli
as a function of concentration was shown to be biphasic. At concentrations less than the bacteriostatic levels, the mode of uptake was not azide-sensitive and was considered to be physical adsorption on the cell surface. At concentrations above the minimal inhibitory level, a second, azide-sensitive, uptake component was functional in addition to the surface adsorption process. This second energy-requiring mode was judged to represent penetration of the cytoplasmic membrane by tetracycline molecules to their sites of inhibitory action. Each mode for a given tetracycline and culture is expressed algebraically by a characteristic Freundlich equation. Resistance in
E. coli
is shown to be a result of diminished transport of antibiotic. However, this resistance was due not to a reduction or loss of a transport mechanism but rather to a requirement for higher antibiotic concentrations before the second mode of uptake could become operative.
Properties of Mitomycin C-sensitive Mutants of
Escherichia coli
K-12
Authors: Otsuji Nozomu
Published: January 2020

Strains hypersensitive to mitomycin C (MC) were isolated from
Escherichia coli
K-12 after treatment with nitrosoguanidine. Of 43 MC-sensitive strains tested for their ultraviolet light (UV) sensitivity and for their ability to reactivate UV-inactivated λ phage, 38 were found to be insensitive to UV irradiation and to be able to reactivate UV-irradiated bacteriophage λ. Some properties of the MC-sensitive,
uvr
+
mutants were analyzed. Synthesis of deoxyribonucleic acid (DNA) in MC-sensitive,
uvr
+
mutants was inhibited at a lower concentration of MC than in the wild-type strain. Mutant cells, labeled with
3
H-thymidine and then exposed to MC, released radioactivity as low molecular weight compounds. The amount of radioactivity released was the same as that from the wild-type strain. MC-sensitive,
uvr
+
mutants, as well as the corresponding wild-type strain, were equally susceptible to induction of prophage φ80 by UV irradiation. However, MC induction of prophage was achieved in MC-sensitive,
uvr
+
mutants at a lower concentration of the antibiotic than in the wild-type strain. Genetic experiments indicated that a gene controlling MC sensitivity is located close to that determining lactose fermentation of
E. coli
. It is situated on episome F′13, and the wild type is dominant to the MC-sensitive allele.
Repair of Deoxyribonucleic Acid in
Haemophilus influenzae
I. X-Ray Sensitivity of Ultraviolet-sensitive Mutants and Their Behavior as Hosts to Ultraviolet-irradiated Bacteriophage and Transforming Deoxyribonucleic Acid
Authors: Setlow Jane K. , Brown Dianne C. , Boling Maxon E. , Mattingly Alice , Gordon Milton P.
Published: January 2020

Seven mutants of
Haemophilus influenzae
were isolated by the criterion of sensitivity to ultraviolet (UV) inactivation of colony formation. These mutants and the wild type were characterized with regard to X-ray inactivation of colony formation, UV induction of division inhibition, the ability of the eight strains to act as recipients to UV-irradiated
H. influenzae
phage and transforming deoxyribonucleic acid (DNA), and the influence of acriflavine on the survival of UV-irradiated transforming DNA with these strains as recipients. The photoreactivable sector of transforming DNA with yeast photoreactivating enzyme was measured for the most UV-sensitive mutant and was found to be greater than that of wild type. Judged by the above criteria, the order of the strains' sensitivities shows some, but by no means complete, correlation from one type of sensitivity characterization to another, indicating that a minimum of two variables is needed to explain the differences in the strains. Acriflavine increases the UV sensitivity of transforming DNA except in the most sensitive mutant. This effect is usually, but not always, more pronounced in the case of the more UV-resistant marker. The acriflavine effect is postulated to be the result of at least two factors: (i) interference with repair of transforming DNA in the host cell, and (ii) interference with the probability of recombination between transforming DNA and host DNA.
Dependence of Diaminopurine Utilization on the Mutational Site of Purine Auxotrophy in
Bacillus subtilis
II. Tracer Experiments
Authors: Shigeura Harold T. , Demain Arnold L.
Published: January 2020

Tracer experiments were carried out in an attempt to explain why guanineless auxotrophs can use diaminopurine as a guanine replacement but nonexacting purine auxotrophs cannot do so. Cell suspensions of the nonexacting purineless
Bacillus subtilis
MB-1356 incorporated more radioactivity from diaminopurine-
2
-
14
C
into nucleic acid than did guanineless
B. subtilis
MB-1517. The radioactivity in MB-1356 ribonucleic acid (RNA) was distributed in both adenine and guanine nucleotides, thus eliminating the possibility that the deamination of diaminopurine to guanine occurred predominantly on the level of nucleoside di- or triphosphates. Strain MB-1517 incorporated adenine-
8
-
14
C
into nucleic acids extremely poorly. This correlated with results obtained with cell-free extracts; strain MB-1517 showed much less adenosine monophosphate (AMP) pyrophosphorylase activity than did MB-1356. Likewise, guanineless MB-1517 converted diaminopurine to its nucleotide much more slowly than did the nonexacting purine auxotroph. The results indicated that the lack of growth of nonexacting auxotrophs on diaminopurine alone is due not to an inability to convert the analogue to nucleic acid adenine but to the greater capacity of the nonexacting auxotrophs to convert diaminopurine to its 5′-ribonucleotide. Presumably, this compound, or a coenzyme analogue produced from it, inhibits growth of mutants which cannot make AMP de novo and only when the medium is devoid of adenine.
Effect of Amino Sugars on Catabolite Repression inEscherichia coli
Authors: Dobrogosz Walter J.
Published: January 2020

N-acetylglucosamine was found to be a good repressor source for catabolite repression of the β-galactosidase system inEscherichia coli. It was found capable of increasing the severity of repression by glucose or gluconate when included in the medium with either of these substrates.N-acetylglucosamine was shown to be assimilated under these conditions, but had no effect on culture growth rates. Its influence on catabolite repression was not altered by growth in the presence of inhibiting levels of penicillin. These findings indicated that catabolite repression may be associated with certain reactions of amino sugar metabolism. A working model has been formulated along these lines and will be used to explore this possible relationship further.
Identification of the Toxic Component ofBrucella abortusEndotoxin and Its Labeling with Radioactive Chromate
Authors: Leong Daniel , Diaz Ramon , Wilson J. B.
Published: January 2020

The evidence obtained from immuno-gel diffusion, centrifugation, and toxicity studies employing the serum iron assay proved that most of the toxicity in an ether-water brucella endotoxin preparation lies in the slow-diffusing component identified as the biologically active endotoxin. Subsequent destruction of the slow-diffusing component by acid hydrolysis resulted in a corresponding loss of toxicity. Chromate-51 was found to attach almost entirely on the slow-diffusing biologically active component and, hence, is a valid label for endotoxin derived from smoothBrucella abortusby the ether-water method.
Antigenic Relationship of the Gram-negative Organism Causing Canine Abortion to Smooth and Rough Brucellae
Authors: Diaz Ramon , Jones Lois M. , Wilson J. B.
Published: January 2020

The use of whole-cell antigens in agglutination and agglutinin-absorption tests showed that the organism causing abortion in dogs is similar to roughBrucella abortus, B. melitensis, andB. ovis, but different from smoothBrucellacultures. Water-soluble antigens obtained by ultrasonic treatment and examined by immuno-electrophoresis and gel diffusion show extensive cross-reactions within the genusBrucella, but little or no cross-reaction with similar antigens from other gram-negative genera in the familyBrucellaceae. The dog organism showed near identity with rough and smoothBrucellacultures on the basis of immuno-gel diffusion tests with water-soluble antigens, but it lacked the lipopolysaccharide-endotoxin associated with the agglutinogen of smooth brucellae. These findings support the proposal of Carmichael and Bruner for the designation of a new species, “Brucella canis.”
Nutrition of
Myxococcus xanthus
FBa and Some of Its Auxotrophic Mutants
Authors: Hemphill H. Ernest , Zahler Stanley A.
Published: January 2020

A defined medium containing 15 amino acids plus salts was used to study the nutrition of
Myxococcus xanthus
FBa. The amino acids phenylalanine, leucine, isoleucine, valine, and methionine were essential for growth, whereas glycine, proline, asparagine, alanine, lysine, and threonine stimulated growth. An unusual pattern of requirement was found in the aromatic amino acids. Phenylalanine was essential and served as the precursor of tyrosine. Growth in the absence of tryptophan was adaptive, with cells reaching a growth rate equal to that of controls after a lag of about a week.
14
C-labeled ribose and glucose were not appreciably metabolized. Auxotrophs requiring purines and pyrimidines were isolated and were used to study the fate of externally supplied nucleic acid derivatives. Appropriate mutants could satisfy their requirements with free bases, nucleosides, and nucleotides, and could hydrolyze nucleic acids and use the products. However, studies using
14
C-ribose-labeled uridine (isolated from a
Salmonella typhimurium
pyrimidine auxotroph) showed that externally supplied nucleic acid derivatives were incorporated almost solely into the nucleic acids of the myxobacters, with little used either for energy-yielding oxidations or other cell anabolism.
Nutritional Induction and Suppression of Fruiting in
Myxococcus xanthus
FBa
Authors: Hemphill H. Ernest , Zahler Stanley A.
Published: January 2020

A defined agar medium (A agar) containing 15 amino acids in concentrations between 0.5 and 2 m
m
was developed for studying the fruiting cycle of
Myxococcus xanthus
FBa. Cells grew only vegetatively in this medium unless the initial concentration of one of nine required or stimulatory amino acids was lowered about 50-fold. In the latter circumstance, fruiting bodies developed after several days of vegetative growth. The conclusion was that fruiting occurred when any amino acid required for normal growth became limiting in the environment. High concentrations (10 m
m
) of phenylalanine, tryptophan, or methionine prevented fruiting without affecting growth. Mutants requiring arginine, thymidine, or adenine could not be induced to fruit by limiting their unique requirement although they responded to the same deprivations which brought about fruiting of the wild type. A histidine auxotroph formed fruiting bodies when histidine was lowered to growth-limiting concentrations, provided that the medium was supplemented with purines. A uracil auxotroph was isolated that, perhaps secondarily, had lost some of the mechanisms which control the formation of fruiting bodies; if uracil was present, it formed fruits even when no amino acid was limiting. No concentration of uracil was sufficient to prevent fruiting. Fruiting bodies were formed when mixtures of the uracil auxotroph and wild-type cells were inoculated on A agar plus uracil, even when 75% of the cells were wild type. Microcysts of both strains were present in the fruiting bodies.
Use of Lysostaphin in the Isolation of Highly Polymerized Deoxyribonucleic Acid and in the Taxonomy of Aerobic
Micrococcaceae
Authors: Klesius Phillip H. , Schuhardt V. T.
Published: January 2020

By use of the staphylolytic enzyme lysostaphin, a method was devised for isolating and purifying highly polymerized deoxyribonucleic acid (DNA) from lysostaphinsusceptible
Micrococcaceae. Staphylococcus aureus
DNA isolated by this procedure gave an estimated molecular weight of ca. 2 × 10
8
and a residual protein content of 2.3%. The mole percentage of guanine + cytosine (GC) present in the DNA from 21 strains of aerobic
Micrococceae
was determined by buoyant density in cesium chloride. DNA from 12 biochemically typical members of the genus
Staphylococcus
gave a mean GC composition of 35.2 ± 0.5 mole per cent. Four biochemically atypical
Staphylococcus
strains and one biochemically typical strain of the genus
Micrococcus
(
M. candicans
) were found to be susceptible to lysostaphin and gave typical
Staphylococcus
spp. GC base ratios. One biochemically atypical member of the genus
Micrococcus
(
M. varians
) was not susceptible to lysostaphin and gave a typical
Micrococcus
spp. GC base ratio. Lysostaphin susceptibility is an easy test to perform, and the results of this test appear to correlate with GC base ratio studies of the genera of
Micrococcaceae
.
Presence and Function of Sulfur-containing Transfer Ribonucleic Acid of
Bacillus subtilis
Authors: Goehler Brigitte , Doi Roy H.
Published: January 2020

Bacillus subtilis
transfer ribonucleic acid (tRNA) was analyzed for the occurrence of thionucleotides by in vivo labeling with
35
S and fractionation by methylated albumin kieselguhr column chromatography. Alkaline hydrolysates of tRNA were also examined by column chromatography and paper electrophoresis, and the amino acid-accepting ability of thionucleotide-containing tRNA was tested after iodine oxidation. The results showed that
B. subtilis
tRNA contains 4-thiouridylate, a second nucleotide with properties similar to 2-thiopyrimidine, and a third unidentified thionucleotide. The amino acid-accepting ability for serine, tyrosine, lysine, and glutamic acid was markedly inhibited after oxidation of the tRNA with iodine, suggesting the presence of thionucleotides in these tRNA species. This inhibition could be reversed by thiosulfate reduction. The iodine treatment totally inactivated all lysine tRNA species, partially inactivated the serine tRNA species, and did not affect the accepting ability for valine. A comparison of tRNA from cells in the log and stationary phases and from spores revealed similar iodine inactivation patterns in all cases. The thionucleotide content in
B. subtilis
tRNA differed from that in
Escherichia coli
, both in extent and in distribution. A possible function of the thionucleotides in tRNA is discussed.
Synthesis of Bacterial Flagella I. Requirement for Protein and Ribonucleic Acid Synthesis During Flagellar Regeneration in
Bacillus subtilis
Authors: Dimmitt K. , Bradford S. , Simon M.
Published: January 2020

A relatively simple immunochemical procedure for estimating flagellar protein was developed. This procedure involved measuring the binding of purified, radioactively labeled, antiflagellar antibodies to bacteria. The assay was used to determine the requirements for ribonucleic acid (RNA) and protein synthesis during flagellar regeneration in
Bacillus subtilis
. Immediate inhibition of flagella development was observed when chloramphenical or puromycin was added to cells. This inhibition indicated the absence of a large pool of flagella precursors that could be assembled in the absence of protein synthesis. When the cells were starved for uracil or treated with actinomycin D to inhibit RNA synthesis, the ability of the cells to regenerate flagella decayed with a half-life of 5.5 min. When
B. subtilis
auxotrophs were starved for tryptophan, they continued to synthesize flagella, although this process was also inhibited by actinomycin D. On the basis of these results, we concluded that (i) the system involved in flagellar regeneration does not have unusual metabolic stability, (ii) regeneration requires both concomitant protein and RNA syntheses, and (iii)
B. subtilis
continues to synthesize messenger RNA during tryptophan starvation.
Lipids of
Salmonella typhimurium
and
Escherichia coli:
Structure and Metabolism
Authors: Ames Giovanna F.
Published: January 2020

The nature and quantity of the phospholipids of
Salmonella typhimurium
and
Escherichia coli
K-12 have been examined. The main classes of phospholipids, phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin have been completely characterized. Four minor compounds have been detected: phosphatidylserine, phosphatidic acid, and two partially characterized lipids. The phospholipid composition of the two organisms is quite similar, the only difference is the absence of one of the minor components and a decreased level of all components in
E. coli
. A study of the turnover of the phosphate in the phospholipids demonstrated no turnover in phosphatidylethanolamine, a slow turnover in phosphatidylglycerol, and a slow turnover in cardiolipin with, possibly, a transfer of phosphate from phosphatidylglycerol to cardiolipin. The amino acid phenylalanine is shown to become incorporated intact into lipidic compounds which have been partially characterized. Methods for the isolation and separation of lipids have been examined for their utility with these bacteria.
Stability In Vitro of Uridine Diphosphoglucose Pyrophosphorylase in
Dictyostelium discoideum
Authors: Wright Barbara E. , Dahlberg Donna
Published: January 2020

The stability of uridine diphosphoglucose pyrophosphorylase was examined in extracts prepared at different stages of development in
Dictyostelium discoideum
. In the early stages, the kinetics of inactivation were nonlinear, and, therefore, it was not possible to determine the specific enzyme activity. In the later stages of development, the enzyme was stable, but it could be rapidly inactivated by a heat-labile inhibitor present in extracts prepared at an early stage.
Bacteriophage Clearance in the Oyster (
Crassostrea virginica
)
Authors: Acton Ronald T. , Evans E. Edward
Published: January 2020

Since relatively few quantitative immunological studies had been conducted with invertebrates, this study was designed to learn more about the immune potential of the oyster, a molluscan representative. Experiments measured the primary and secondary clearance rates of T2 coliphage in the oyster. The fate of phage injected intracardially or intramuscularly was traced by measuring serum and tissue fluid plaque-forming unit levels at various times postinjection. Phage-neutralizing activity was also measured. Although circulating T2-neutralizing antibody was not induced in the oyster, secondary injections of T2 were cleared more rapidly than primary injections. The difference in clearance rates between primary and secondary groups was not as pronounced in the oyster as in the lemon shark, an animal capable of producing high levels of serum antibody to T2.
Genetic Mapping of Loci for Glucose-6-Phosphate Dehydrogenase, Gluconate-6-Phosphate Dehydrogenase, and Gluconate-6-Phosphate Dehydrase in
Escherichia coli
Authors: Peyru Graciela , Fraenkel D. G.
Published: January 2020

The loci on the
Escherichia coli
genome of mutations affecting the constitutive enzymes glucose-6-phosphate dehydrogenase (
zwf
) and gluconate-6-phosphate dehydrogenase (
gnd
), and the inducible enzyme gluconate-6-phosphate dehydrase (
edd
), were determined by conjugation and transduction experiments, chiefly by three-factor crosses. They are in the same region of the chromosome, and their order is
gnd—his—
(
edd, zwf
)
—aroD; gnd
and
his
are cotransduceable, as are
zwf
and
edd
. The position of
gnd
in
Salmonella typhimurium
was shown to be similar to that in
E. coli
.
Genetic Map Position of the Gluconate-6-Phosphate Dehydrogenase Gene inSalmonella typhimurium
Authors: Murray M. L. , Klopotowski T.
Published: January 2020

Gluconate-6-phosphate dehydrogenase (GND) is genetically determined inSalmonella typhimuriumby a locus (gnd) mapping between the somatic antigen (rfb) and histidine (his) operons. The enzyme is constitutive. Strains ofSalmonellacarrying an F′ genetic element which contains thegnd+gene have GND activity two to three times that of the wild type. This gene dosage effect was used to determine that the GND reaction is not rate-limiting for the metabolism of glucose by the pentose shunt inS. typhimurium.
Initiation of Bacterial Spore Germination
Authors: Vary J. C. , Halvorson H. O.
Published: January 2020

To investigate the problem of initiation in bacterial spore germination, we isolated, from extracts of dormant spores of
Bacillus cereus
strain T and
B. licheniformis
, a protein that initiated spore germination when added to a suspension of heat-activated spores. The optimal conditions for initiatory activity of this protein (the initiator) were 30 C in 0.01 to 0.04
m
NaCl and 0.01
m
tris(hydroxymethyl)aminomethane (
p
H 8.5). The initiator was inhibited by phosphate but required two co-factors,
l
-alanine (1/7 of
K
m
for
l
-alanine-inhibited germination) and nicotinamide adenine dinucleotide (1.25 × 10
−4
m
). In the crude extract, the initiator activity was increased 3.5-fold by heating the extract at 65 C for 10 min, but the partially purified initiator preparation was completely heat-sensitive (65 C for 5 min). Heat stability could be conferred on the purified initiator by adding 10
−3
m
dipicolinic acid. A fractionation of this protein that excluded
l
-alanine dehydrogenase and adenosine deaminase from the initiator activity was developed. The molecular weight of the initiator was estimated as 7 × 10
4
. The kinetics of germination in the presence of initiator were examined at various concentrations of
l
-alanine and nicotinamide adenine dinucleotide.
Repair-induced Changes in Yeast Radiosensitivity
Authors: Patrick M. H. , Haynes R. H.
Published: January 2020

Potentially lethal X-ray or ultraviolet damage in the diploid yeast,
Saccharomyces cerevisiae
, can be reversed if the irradiated cells are incubated in distilled water or buffer for a number of hours prior to plating. This phenomenon is called liquid-holding recovery. We found that the liquid-holding procedure served not only to restore the viability of the irradiated cells, but also to alter their sensitivity to further doses of radiation. Specifically, the ultraviolet sensitivity of cells which had undergone liquid-holding recovery was markedly decreased, whereas their X-ray sensitivity appeared to be slightly increased. These sensitivity changes were qualitatively the same irrespective of whether the initial radiation exposure was to X rays or ultraviolet light. (In contrast, the radiation sensitivity of cells which had undergone maximal photoreactivation was essentially the same as that of untreated controls.) It is suggested that these changes in radiosensitivity are the result of structural alterations induced in the cell's deoxyribonucleic acid by the execution of at least the initial steps of a deoxyribonucleic acid repair process during the liquid-holding period.
Regulation and Function of Lactate Oxidation in
Streptococcus faecium
Authors: London Jack
Published: January 2020

Regulation of the synthesis and function of an
l
(+)-specific lactate-oxidizing enzyme system found in a homofermentative
Streptococcus
was investigated. With the exception of fructose, aerobic growth at the expense of a variety of substrates resulted in the formation of a lactate oxidation system; anaerobic growth resulted in a marked reduction or complete loss of lactate-oxidizing activity. Growth on fructose, under aerobic and anaerobic conditions, invariably produced a decrease in the activity of the lactate oxidation system. A negative control, activated by an early intermediate product of glycolysis, appeared to be responsible for repression of the lactate-oxidizing enzyme(s). The enzyme system confers upon the organism the ability to grow aerobically at the expense of
l
(+)-lactic acid.
Isoleucine and Valine Metabolism of
Escherichia coli
XIV. Effect of Thiaisoleucine
Authors: Szentirmai A. , Umbarger H. E.
Published: January 2020

Thiaisoleucine (2-amino-3-methylthiobutyrate) completely inhibited the growth of strain K-12 of
Escherichia coli
at a concentration of 5 × 10
−3
m
. The inhibition was antagonized by growth-factor amounts of
l
-isoleucine. Thiaisoleucine inhibited the deamination of threonine and the transfer of
14
C-isoleucine to soluble ribonucleic acid and underwent transamination with α-ketoglutarate as the amino acceptor. In each case, the analogue appeared to be less effective than isoleucine as either an inhibitor or substrate.
Kinases in
Leuconostoc mesenteroides
Authors: DeMoss R. D.
Published: January 2020

Enzyme extracts of
Leuconostoc mesenteroides
were found to contain at least four separate kinases: one active with glucose, glucosamine, and
N
-acetylglucosamine; one active with fructose and mannose; and two active with gluconate, one constitutive and one inducible. The molecular sizes of all the kinases, estimated from sucrose gradient centrifugation, are about the same, 37,000 to 50,000 daltons, except the constitutive gluconate kinase, which is about 100,000 daltons. Apparent Michaelis constants were calculated for all of the substrates mentioned. The kinases are separable on triethylaminoethyl cellulose.
Control of the Synthesis of Macromolecules During Amino Acid and Thymine Starvation in
Bacillus subtilis
Authors: Anraku Naoyo , Landman Otto E.
Published: January 2020

Studies of Maaløe, Lark, and others with amino acid- and thymine-starved cultures revealed successive steps in the biosynthesis of
Escherichia coli
chromosomes. In this study, the corresponding mechanisms in
Bacillus subtilis
168 were examined. Using a strain requiring both thymine and tryptophan, we found that, 3 hr after the start of amino acid starvation, when the deoxyribonucleic acid (DNA) content of the culture had increased 40 to 50%, DNA synthesis ceased. After 4 to 5 hr, 100% of the cells were immune to thymineless death; their chromosomes had presumably been completed. Immune cultures slowly incorporated
3
H-thymine. Thymine incorporation increased 20-fold 30 min after readdition of amino acids, indicating reinitiation of chromosome synthesis. Simultaneous presence of amino acids and thymine was required for reinitiation. If 5-bromouracil (5-BU) was added instead of thymine, newly replicated DNA segments could be separated by centrifugation in CsCl. Analysis of the CsCl fractions by a transformation assay showed that the order in which the markers were synthesized was
ade-16, thr-5, leu-8, metB5
. Less than half the chromosomes started resynthesis synchronously in 5-BU. Nevertheless, chromosome alignment in the amino acid-starved culture is probably very good: marker frequency analysis of its DNA gives the same normalized frequencies as DNA from “perfectly” aligned spores. Full viability is maintained in the chromosome-arrested culture for 10 hr in thymine-free medium in the absence or presence of amino acids. In the latter condition, protein synthesis proceeds, and the cells filament and become more lysozyme-sensitive. Such cells must be incubated and plated on hypertonic or on slow-growth media; otherwise, they undergo “quasiosmotic” thymineless death. This death is thus apparently not directly attributable to any damage of chromosomal DNA. Further, weakening of the teichoic acid portion of the cell wall is not involved, since
32
P incorporation into teichoic acid is normal. Chloramphenicol prevents quasiosmotic thymineless death and also inhibits
32
P incorporation into teichoic acid. Chromosome-synthesizing cultures suffer thymineless death of two types: quasiosmotic death, and death insusceptible to osmotic rescue.
Ribosome Development and the Methylation of Ribosomal Ribonucleic Acid
Authors: Sypherd Paul S.
Published: January 2020

Immature ribonucleoprotein particles accumulate in amino acid-starved cells of a relaxed mutant of
Escherichia coli
. The ribonucleic acid (RNA) of these particles is nonmethylated in cells starved for methionine. However, in bacteria starved for arginine, lysine, or histidine, the RNA of these particles is one-half methylated. The relationship of submethylation to a structural alteration in the same RNA was studied. The results of kinetic studies showed that submethylation and the structural transition are not causally related, since they are described by different rate constants. Moreover, it was possible to accumulate fully methylated immature-particle RNA that possessed the sedimentation and chromatographic properties of nonmethylated RNA. It was concluded that, during the normal course of ribosome development, methylation of ribosomal RNA is completed prior to the final maturation steps.
Induction and Propagation of a
Bacillus subtilis
L Form in Natural and Synthetic Media
Authors: Burmeister H. R. , Hesseltine C. W.
Published: January 2020

The L form of
Bacillus subtilis
NRRL B-3275 was induced in a 7% NaCl broth medium and subsequently propagated in natural and synthetic media. The L form grew readily in tryptone broth supplemented with glucose, NaCl, and phosphate buffer, and in a synthetic medium containing only glucose and biotin, in addition to the required salts. Successive transfers from the bacillus inoculum and subsequent large bodies in the tryptone broth with 7% NaCl resulted in gradual selection or transition from the bacillary form to a stable L form without the addition of an antibiotic. The number of viable granules attained in the broth culture exceeded 9 × 10
7
per ml, and numerous large bodies were always present in rapidly growing cultures.
Variation in the Fine Structure of a Marine Achromobacter and a Marine Pseudomonad Grown Under Selected Nutritional and Temperature Regimes
Authors: Wiebe William J. , Chapman George B.
Published: January 2020

Certain features of the fine structure of a marine achromobacter and a marine pseudomonad were dependent upon the conditions of growth. Cells of achromobacter grown at 10 C in a low peptone-seawater (SW) medium displayed the characteristic morphology of the achromobacter: a regularly undulant outer element of the cell wall and a planar inner element, tightly packed ribonucleoprotein (RNP) particles in the cytoplasm, deoxyribonucleic acid (DNA) disposed in a lobate manner, and dense inclusion bodies. Few mesosomes, however, were seen. Cells of achromobacter grown at 10 C in a high peptone-SW medium had larger and more highly organized mesosomes. At 22 C, in a low peptone-SW medium, no mesosomes were seen, but the inclusions were more frequently seen and were larger in the achromobacter cells. At 22 C, in a high peptone-SW medium, these cells revealed the greatest variation in cellular morphology. They contained both small and large mesosomes, or no mesosomes, and both small and large inclusions, or no inclusions. Pseudomonad cells at 10 C in a low peptone-SW medium revealed a typical gram-negative morphology: double-layered, irregularly undulant cell wall; more nearly planar cytoplasmic membrane; densely stained, lightly packed RNP particles; finely fibrillar, axially disposed DNA; simple mesosomes. At 10 C, in a high peptone-SW medium, pseudomonad cells revealed associated strands of material and intracytoplasmic ringlike structures. At 22 C, in a low peptone-SW medium, pseudomonad cells had a more undulant cell-wall and a more nearly planar cytoplasmic membrane. At 22 C, in a high peptone-SW medium, these cells revealed prominent blebs of the cell wall.
Hemolysin and Peroxide Activity ofMycoplasmaSpecies
Authors: Cole B. C. , Ward J. R. , Martin C. H.
Published: January 2020

Various methods for the detection of hemolysin production byMycoplasmaspecies were compared. Inoculation of blood-agar by the push-block method and by use of concentrated mycoplasma cell suspensions was compared with the agar-overlay technique. The preferred method was direct surface inoculation of concentrated suspensions onto the blood-agar. Among the conditions tested, refrigeration of 48-hr cultures gave the best results. A wide variety of mycoplasma species were tested for hemolytic activity towards rabbit, sheep, guinea pig, duck, and chicken bloods. Guinea pig erythrocytes were found to be the most susceptible to lysis by mycoplasma, and rabbit erythrocytes were found to be the least susceptible. A sensitive technique for the detection of peroxide production by mycoplasma strains, employing agar containing benzidine and sheep blood, was used. With this method, peroxide production could be correlated with hemolysis on blood-agar. Peroxidase and catalase inhibited both the benzidine reaction and hemolysis. It was concluded that the major hemolysin of theMycoplasmaspecies examined is a peroxide.
In Vivo Interaction of Endotoxin with a Plasma Lipoprotein Having Esterase Activity
Authors: Skarnes Robert C.
Published: January 2020

Circulating endotoxin was specifically precipitated from plasma samples withdrawn from three different animal species subsequent to parenteral injection of the toxin. Lipoprotein-positive staining and esterase activity were demonstrated on the precipitation lines formed in immunodiffusion, thus establishing the in vivo interaction of endotoxin with a plasma lipoprotein having esterase activity. Evidence was given to show that the intensity of this interaction in circulating plasma increased gradually with time. The concordance of this in vivo inter-action with the in vitro degradation and inactivation of endotoxin by plasma esterases is discussed.
Synthesis of Teichoic Acids VII. Synthesis of Teichoic Acids During Spore Germination
Authors: Chin Theresa , Younger Jerry , Glaser Luis
Published: January 2020

The synthesis of teichoic acids has been examined during germination in
Bacillus licheniformis
ATCC 9945 and in
B. subtilis
W-23. Teichoic acids are absent from the spores of both organisms.
B. licheniformis
spores lack the enzymes responsible for teichoic acid synthesis. The appearance of these enzymes during germination is correlated with the appearance of teichoic acids in the cell. The appearance of teichoic acid-synthesizing enzymes and of teichoic acids in the cell are inhibited by the addition of chloramphenicol to the germination medium. In
B. subtilis
W-23 the situation is similar for the synthesis of polyribitolphosphate. The synthesis of glucosyl polyribitolphosphate is only partially inhibited by chloramphenicol, puromycin, and penicillin, and uridine diphosphate-
d
-glucose polyribitol-phosphate glucosyl transferase can be demonstrated in spores. The possible implications of some of these observations are discussed.
Prevention of Staphylococcal Bacteriophage Activity by Antigen A Precipitins in Human Sera
Authors: Martin R. Russell , White Arthur
Published: January 2020

Antigen A precipitins in human sera prevented plaque formation and propagation of staphylococcal bacteriophages. Over 20% of total IgG was removed from human sera by absorption with staphylococci containing antigen A. The specific precipitating antibody in rabbit antisera formed lines of idenity with antigen A precipitins in lower dilutions of human sera but formed lines of nonidenity with antigen A precipitins in higher dilutions of the same sera, suggesting both specific and nonspecific antigen A precipitins in human sera. The specific and nonspecific antigen A precipitins in human sera may prevent the in vivo activity of staphylococcal bacteriophages which have been demonstrated previously in animals whose sera do not contain either specific or nonspecific antigen A precipitins.
Electron Microscopy of Immune Disruption of Leptospires: Action of Complement and Lysozyme
Authors: Anderson D. L. , Johnson R. C.
Published: January 2020

Sequential disruption of the sheath of avirulent leptospires of the serotype
canicola
with antibody and complement was monitored by electron microscopy. Loosening and separation of the sheath from the protoplasmic cylinder was observed as early as 2 min after exposure to complement. Virulent leptospires of this serotype were morphologically intact after 1 hr of exposure to antibody and complement. Similarly, treatment of leptospires of the serotype
patoc
with normal serum and complement severely damaged the sheath structure. Removal of the sheath of both serotypes permitted lysozyme to act on the wall of the protoplasmic cylinder. Thus, morphological evidence for the location of the mucopeptide-containing structure of these leptospires was obtained. Viable leptospires with intact sheaths were resistant to lysozyme alone. Sections and negatively stained preparations of sheaths of serotypes
canicola
and
patoc
revealed three dense layers with two intermediate light zones and an overall thickness of about 110 A. A periodicity of 40 A was observed in sheath fragments produced by complement. The 70 A wallmembrane complex of leptospires of both serotypes consisted of two dense layers with an intermediate light zone. Structures apparent after removal of the outer sheath included membranous bodies or mesosomes, axial filaments attached to terminal knobs at opposite ends of the cell, and electron-dense intracellular bodies.
Pneumonia Due to Mycoplasma in Gnotobiotic Mice III. Lesions in the Lungs of Gnotobiotic Mice After Multiple Intranasal Inoculations of Broth Cultures of
Mycoplasma pneumoniae
Authors: Organick Avrum B. , Lutsky Irving I.
Published: January 2020

Lung lesions characterized by extensive peribronchial and perivascular round cell infiltration and intrabronchial plugging with polymorphonuclear leukocytes were produced in 5 of 44 Ha/ICR gnotobiotic mice sacrificed 3 to 10 days after three intranasal inoculations of broth cultures of
Mycoplasma pneumoniae
. After 10 days, no significant lesions were seen, and the proportion of lungs positive for
M. pneumoniae
dropped off sharply.
M. pneumoniae
persisted for longer periods (up to 24 days) in the trachea, nasopharynx, and anterior nares. These findings would seem to represent a self-limited respiratory infection due to
M. pneumoniae
in gnotobiotic mice. Ring forms within granular alveolar pneumocytes were seen by electron microscopy in the lungs of triply inoculated gnotobiotic controls receiving sterile horse-serum broth as well as in the lungs of mice receiving broth cultures of
M. pneumoniae
. Ring forms must now be considered to be part of the nonspecific cellular reactions of pneumocytes to foreign substances in the lungs of mice rather than intracytoplasmic developmental forms of mycoplasma as previously proposed.
A Novel Apical Corpuscle in Hyphae of
Mucor rouxii
Authors: Bartnicki-Garcia S. , Nelson Nancy , Cota-Robles E.
Published: January 2020

Median longitudinal sections of germ tube apices of
Mucor rouxii
revealed the presence of a single, roughly hemispherical, electron-dense organelle, in intimate contact with the apical cell wall. Conceivably, this “apical corpuscle” may be responsible for the emission of the germ tube and its continued apical growth.
Fatty Acid Composition of
Neisseria
Species as Determined by Gas Chromatography
Authors: Lewis Vester J. , Weaver Robert E. , Hollis Dannie G.
Published: January 2020

Duplicate cultures of 53 strains representing 9 species of
Neisseria
were analyzed by gas-liquid chromatography for cellular fatty acids.
N. sicca, N. mucosa, N. flava, N. flavescens, N. perflava, N. subflava
, and the several serotypes of
N. meningitidis
examined were found to comprise a fairly homogeneous group on the basis of the percentages of individual fatty acids present. Lactose-fermenting
Neisseria
also were in this group.
N. catarrhalis
, however, contained decanoic acid in addition to the acids occurring in the other species. Moreover, the 18 C-saturated and monoenoic acids together constituted 36% of the total fatty acid composition for
N. catarrhalis
, while the comparable mean value for the other species was less than 13%.
Dynamics in Development of Experimental Streptococcal Immunity in Mice
Authors: Michael J. Gabriel , Massell Benedict F.
Published: January 2020

The interrelation between the humoral and cellular factors in the development of immunity to experimental streptococcal infection was investigated. Early resistance to infection was caused by stimulating the phagocytic cells to function efficiently in the absence of opsonins. Subsequently, the appearance of cytophilic antibodies provided further means for elimination of streptococci. Thus, in the early stages of specific antistreptococcal immunity, resistance was observed in the absence of circulating anti-M antibodies. The type-specific antibodies that appeared in the later stage did not seem to improve clearance of streptococci in the splanchnic tissues. After an intravenous lethal challenge of mice with virulent streptococci, these antibodies did not provide increased protection. The circulating anti-M antibodies were shown to play a beneficial, indeed, a crucial, role when the infection occurred in a region in which the phagocytic cells were present in a rather limited number.
Pl-mediated Transduction of a Gene That Controls Radiation Sensitivity and Capsular Polysaccharide Synthesis from
Shigella dysenteriae
to
Escherichia coli
Authors: Markovitz Alvin , Rosenbaum Nancy , Baker Bruce
Published: January 2020

When
Shigella dysenteriae
strain 60 is used as a donor and
Escherichia coli
K-12 strains that are ultraviolet (UV)-sensitive, mucoid, and proline-requiring (Pro
−
) are employed as recipients, selection for Pro
+
yields 2 to 6% nonmucoid clones. All of the nonmucoid clones examined are UV-resistant. Most of the nonmucoid UV-resistant transductants are partial diploids for the genes being studied. When these
Shigella-Escherichia
hybrids are used as donors with the same
E. coli
recipients, the cotransduction of Pro
+
and nonmucoidness is greatly increased (59 to 94% cotransduction). All of these nonmucoid transductants examined were also UV-resistant. The results indicate that
Shigella
contains an allele (designated Sh
proC
+
) homologous to
proC
of
E. coli
and a second linked allele (designated Sh
capR
+
) homologous to the
capR
allele of
E. coli
. The Sh
capR
+
allele changes the phenotype of certain
E. coli
strains from mucoid UV-sensitive (
capR6
) or very sensitive (
cap
R9) to nonmucoid and UV-resistant. Unanticipated
capR
allele interactions in the partial diploid hybrids are described.