bluuebunny/crossref_metadata_2025 huggingface dataset:
Regulatory Properties of Acetokinase from
Veillonella alcalescens
Authors: Pelroy R. A. , Whiteley H. R.
Published: January 2020

Acetokinase from
Veillonella alcalescens
catalyzes the virtually irreversible synthesis of adenosine triphosphate from acetyl phosphate and adenosine diphosphate. Kinetic analysis revealed that the enzyme was activated by acetyl phosphate and inhibited by adenosine triphosphate. Velocity curves obtained with increasing amounts of adenosine diphosphate were of the Michaelis-Menten type (rectangular hyperbolas) under all conditions employed. However, velocity curves generated by varying the level of acetyl phosphate were sigmoidal, suggesting homotropic interactions for this substrate. Alteration of the
p
H of the reaction mixture from 7.4 to 10 or addition of a substrate analogue, propionyl phosphate, resulted in the loss of cooperativity and changed the values of the Hill coefficient from 3 to 1. Data obtained in experiments with propionyl phosphate suggested the existence of separate effector sites on the enzyme. The inhibition curves for adenosine triphosphate were also sigmoidal with Hill coefficients ranging between 1 and 3, depending on the concentration of acetyl phosphate. Sedimentation studies with the partially purified enzyme indicated a polymeric structure with a maximum molecular weight of about 90,000 daltons; a subunit of approximately 29,000 daltons was also detected.
p
H-Conditional, Ammonia Assimilation-Deficient Mutants of
Hydrogenomonas eutropha
: Isolation and Growth Characteristics
Authors: Strenkoski Leon F. , DeCicco B. T.
Published: January 2020

Two mutants of the facultative autotroph
Hydrogenomonas eutropha
were isolated by using a modified penicillin selection method. The mutation involved was unusual in that its effect on cellular growth was conditional with regard to extracellular
p
H and the type of substrate employed. Growth of both mutants was abnormal under autotrophic conditions and during heterotrophic cultivation in the presence of organic substrates which lacked an amino group. Abnormal growth was characterized by linear growth rates which were low at
p
H 6.0 and moderate at
p
H 7.2. In contrast, growth of the mutants was normal on most amino acids. Those substrates yielding abnormal growth were oxidized at normal rates by the mutants, indicating the mutation did not impair their uptake or metabolism. The data suggest that the mutants are defective in their ability to assimilate inorganic nitrogen into organic forms, and this defect is strongly influenced by
p
H.
p
H-Conditional, Ammonia Assimilation-Deficient Mutants of
Hydrogenomonas eutropha
: Evidence for the Nature of the Mutation
Authors: Strenkoski Leon F. , DeCicco B. T.
Published: January 2020

Two amination-deficient mutants of
Hydrogenomonas eutropha
, characterized by
p
H-dependent linear growth on non-amino acid substrates, were investigated to determine the exact nature of the mutation. Glutamate dehydrogenase, the only aminating enzyme found in wild-type cells, was present at similar levels in mutant cells. Phenylalanine and aspartate, which allowed normal growth of the mutants, could transaminate 2-oxoglutarate to glutamate, whereas alanine, which does not support normal growth, could not transfer its amino nitrogen to form glutamate. In
H. eutropha
,
l
-alanine is apparently synthesized by β-decarboxylation of aspartate. Studies with NH
4
+
ions as the sole nitrogen source demonstrated that growth rates of the mutant strains were dependent on both extracellular
p
H and NH
4
+
ion concentration. Comparison of these results revealed that the growth rate of mutant cultures was proportional to the concentration of extracellular NH
3
. Wild-type cultures were not dependent on extracellular NH
3
since exponential growth rates did not vary with
p
H or NH
4
+
ion concentration. The results suggest that the mutant strains lack an NH
4
+
ion transport system and consequently are dependent on NH
3
diffusion which does not support optimal amination rates. The significance of the findings for the amino acid metabolism of
H. eutropha
is discussed.
Control of Tryptophan Biosynthesis by the Methyltryptophan Resistance Gene in
Bacillus subtilis
Authors: Hoch S. O. , Roth C. W. , Crawford I. P. , Nester E. W.
Published: January 2020

5-Methyltryptophan-resistant mutants derived from
Bacillus subtilis
strain 168 synthesize all of the tryptophan biosynthetic enzymes constitutively and excrete tryptophan. These mutants can be divided into three classes: class 1, low enzyme level and low rate of tryptophan excretion; class 2, high enzyme level and intermediate rate of tryptophan excretion; and class 3, high enzyme level and high rate of tryptophan excretion. A bradytrophic requirement for phenylalanine is correlated with the rate of tryptophan excretion. The phenylalanine requirement is relieved when the rate of tryptophan excretion is reduced by either (i) lowering the level of the tryptophan enzymes, (ii) reducing the supply of a tryptophan precursor (chorismate), or (iii) stopping tryptophan synthesis by a mutational block in the pathway. All of the mutants map in a region of the chromosome previously reported as the
mtr
locus. Our data show that synthesis of the tryptophan enzymes is controlled through the
mtr
locus but not influenced by precursors of tryptophan.
Growth of Streptococcal Protoplasts and L-Colonies on Membrane Filters
Authors: Wyrick Priscilla B. , Gooder Harry
Published: January 2020

Membrane filters (Millipore Corp.; pore sizes 1.2 to 0.22 μm) were placed on the surface of L-phase growth medium solidified with agar. The filter and the surrounding medium were inoculated with either protoplasts or stable broth-grown L-phase variants obtained from
Streptococcus faecium
strain F24. The L-phase inoculum gave rise to viable L-colonies on the filters and on the medium, whereas protoplasts gave colony formation only on the medium. However, when the Millipore filters were covered by a layer of solid L-phase medium, 75 μm or greater in depth, before inoculation with protoplasts, colony formation resulted but with atypical morphology. In contrast, inoculation of protoplasts on Nuclepore and Sartorius membrane filters did give rise to L-colonies on the surface and underneath the filters after 2 days of incubation at 37 C. Submicroscopic, viable L-phase elements produced during colony formation were capable of passing through membrane filters with pore channels as small as 0.22 μm; these elements required transfer from underneath the filters to fresh agar medium in order to develop into L-phase colonies. Membrane filters were also placed on the surface of L-phase growth medium solidified with gelatin. Inoculation of the filters and surrounding medium with a lysozyme-prepared protoplast suspension gave rise to streptococci on the surface of the filters and on the medium. However, inoculation with the stable broth-grown L-phase variants gave rise to atypical colonies on the medium and only small patches of abortive growth on the filters.
Biosynthesis of T1 Antigen in
Salmonella
: Biosynthesis in a Cell-Free System
Authors: Nikaido Hiroshi , Sarvas Matti
Published: January 2020

A particulate fraction from a T1 form of
Salmonella typhimurium
incorporated radioactivity from uridine diphosphate (UDP)-
14
C-glucose into products associated with the particulate enzyme. A major fraction of the incorporated radioactivity was found in the cell wall lipopolysaccharide fraction. Acid hydrolysis of incorporation products produced labeled galactose, ribose, and also glucose. The incorporation of glucose could be dissociated from the incorporation of galactose and ribose under certain conditions, and was assumed to represent incorporation into a polymer not related to T1 antigen. The incorporation of galactose and ribose probably represented the synthesis of T1 side chains of lipopolysaccharide, because (i) particulate fractions from non-T1 strains incorporated much less of these sugars and (ii) periodate oxidation and borohydride reduction converted a large portion of incorporated galactose residues into arabinose. The latter finding indicates that the galactose residues are galactofuranosides substituted either at C2 or C3; about 70% of the galactose residues in T1 side chains are known to be galactofuranosides substituted at C3. UDP-
14
C-galactose preparation used was not contaminated by UDP-
14
C-galactofuranose; therefore pyranose-to-furanose conversion must have taken place at some step during the reactions described above. The mechanism of conversion of galactose to ribose is not clear, but it was not found to involve a selective elimination of C1 or C6 of galactose or glucose.
Electron Microscopy of the Altered Spore Morphology of a Ribonucleic Acid Polymerase Mutant of
Bacillus subtilis
Authors: Korch Christopher T. , Doi Roy H.
Published: January 2020

Electron microscopy was used to analyze sporulating cells and spores of
Bacillus subtilis
mutants (Rif
r
) which are resistant to rifampin, an inhibitor of ribonucleic acid polymerase. The spores of Rif-18 are pleomorphic and frequently exhibit terminal knobs. These knobs first occur during late stage IV and early stage V of sporulation and are extensions of the inner and outer spore coats. Since the rifampin resistance and altered spore morphology of Rif-18 are 100% cotransformable, these data suggest that the altered spore morphology is the result of an alteration in ribonucleic acid polymerase genes. The morphology and physical dimensions are also reported for spores from Rif-11, Rif-15, and Rif-21. Significant differences in size from the wild type were observed for these mutants.
Selection of Cells Transformed to Prototrophy for Sporulation Markers
Authors: Hoch James A.
Published: January 2020

A method is presented for reproducible quantitative selection of recombinants for spore markers in transformation analysis.
Biosynthesis During Recovery of Heat-Injured
Salmonella typhimurium
Authors: Pierson Merle D. , Tomlins Richard I. , Ordal Z. John
Published: January 2020

Salmonella typhimurium
7136 incorporated label from glucose-
U
-
14
C
into nucleic acids, lipids, and pool material during recovery from heat injury. There was very little incorporation of label into protein during recovery.
Germination Requirements of
Bacillus macerans
Spores
Authors: Sacks L. E. , Thompson P. A.
Published: January 2020

2-Phenylacetamide is an effective germinant for spores of five strains of
Bacillus macerans
, particularly in the presence of fructose. Benzyl penicillin, the phenyl acetamide derivative of penicillin, and phenylacetic acid are also good germinants.
l
-Asparagine is an excellent germinant for four strains. α-Amino-butyric acid is moderately effective. Pyridoxine, pyridoxal, adenine, and 2,6-diaminopurine are potent germinants for NCA strain 7X1 only.
d
-Glucose is a powerful germinant for strain B-70 only.
d
-Fructose and
d
-ribose strongly potentiate germination induced by other germinants (except
l
-asparagine) but have only weak activity by themselves. Niacinamide and nicotinamide-adenine dinucleotide, inactive by themselves, are active in the presence of fructose or ribose. Effects of
p
H, ion concentration, and temperature are described.
Effect of Nalidixic Acid on Semiconservative Replication and Repair Synthesis After Ultraviolet Irradiation inEscherichia coli
Authors: Eberle Helen , Masker Warren
Published: January 2020

Both semiconservative deoxyribonucleic acid replication and “extensive repair” synthesis, after ultraviolet irradiation, appear to be blocked by nalidixic acid. These findings suggest that the agent(s) responsible for both of these modes of replication, or some necessary common process or structure, is affected by this drug.
Isolation and Characterization of Nonconverting Mutants of Bacteriophage ε
34
Authors: Wright Andrew , Barzilai Neomi
Published: January 2020

ε
34
Is a converting bacteriophage which brings about a glucosylation of the O antigen in the E group salmonella, thus producing antigen 34. Uridine diphosphate glucose is the precursor of antigen 34 and a glucosyl-lipid is an essential intermediate in this process. Mutants of ε
34
which cannot produce antigen 34 have been isolated. Cells lysogenic for these mutants are of two types. Type 1 mutant lysogens cannot form the glucosyl-lipid intermediate; those of type 2 can form glucosyl-lipid but are unable to transfer glucose from the lipid to the O antigen.
Induction of Mutants of
Staphylococcus aureus
100 with Increased Ability to Produce Enterotoxin A
Authors: Friedman Mischa E. , Howard Mary B.
Published: January 2020

As a result of serial exposures to a mutagenic agent,
N
-methyl-
N
′-nitro-
N
-nitrosoguanidine, the yield of enterotoxin A produced by the last mutant in the series was increased nearly 20-fold over the amount produced by the parent
Staphylococcus aureus
100.
Regulation at the Phosphoenolpyruvate Branchpoint in
Azotobacter vinelandii:
Pyruvate Kinase
Authors: Liao Cheng-Liang , Atkinson Daniel E.
Published: January 2020

Pyruvate kinase (EC 2.7.1.40) from
Azotobacter vinelandii
responds sharply to the adenylate energy charge, with a decrease in activity at high values of charge, as expected for an enzyme of an adenosine triphosphate-regenerating sequence. Glycolytic intermediates, especially glucose 6-phosphate, fructose 6-phosphate, and fructose-1,6-diphosphate, strongly stimulate the reaction and overcome the inhibition caused by high values of energy charge. Thus, the properties of this enzyme depend on interaction between energy charge and the concentrations of hexose phosphates. The properties of pyruvate kinase, together with those of phosphoenolpyruvate carboxylase, aspartokinase, and citrate synthase, seem adapted to provide appropriate partitioning of phosphoenolpyruvate between competing pathways in response to metabolic need.
Endogenous Dark Respiration of the Blue-Green Alga,
Plectonema boryanum
Authors: Padan Etana , Raboy Bilha , Shilo Moshe
Published: January 2020

Endogenous dark respiration in the blue-green alga
Plectonema boryanum
is markedly affected by preincubation in the light: it can be increased from a basal rate of 5 nmoles of O
2
to 55 nmoles of O
2
per mg of cell protein per min after exposure of the cells to light for 8 to 10 hr. Under conditions of enhanced dark respiration, cyanophage multiplication in the dark increases drastically and approaches the cyanophage yields obtained in photosynthesizing
Plectonema
cells. This implies that the biosynthetic capabilities of the algal cells, at least with respect to viral synthesis, can be similar in the dark to those in the light. The enhanced endogenous respiration rate was found to be dependent on photoassimilation of CO
2
and on protein synthesis. The implications of these findings with respect to obligate photoautotrophic metabolism in blue-green algae are discussed.
Purification, Properties, and Regulation of Glutamic Dehydrogenase ofBacillus licheniformis
Authors: Phibbs P. V. , Bernlohr R. W.
Published: January 2020

Cell-free extracts ofBacillus licheniformisandB. cereuswere found to contain high specific activities of nicotinamide adenine dinucleotide phosphate (NADP)-dependent-l-glutamate dehydrogenase [EC 1.4.1.4;l-glutamate: NADP oxidoreductase (deaminating)]. Maximum specific activities were found in extracts of cells during the late exponential phase of growth when ammonium ion served as the sole source of nitrogen. Extremely low specific activities were detected throughout the growth cycle whenl-glutamate or Casamino Acids served as the source of carbon and nitrogen. The enzyme was purified 55-fold from crude extracts ofB. licheniformis, and apparent kinetic constants were determined. Sigmoidal saturation kinetics were not observed, and various adenylates had no effect on the enzyme. Repression of enzyme synthesis during growth onl-glutamate or Casamino Acids was partially overcome by additions of glucose or pyruvate, and this apparent derepression was totally abolished by inhibitors of ribonucleic acid and protein synthesis. Similarly, additions ofl-glutamate or Casamino Acids to cells growing on glucose-ammonium ion resulted in strong repression of enzyme synthesis. It is suggested that the enzyme serves an anabolic role in metabolism. Nicotinamide adenine dinucleotide-dependent glutamate dehydrogenase activity was not detected in five species ofBacillus, irrespective of nutritional conditions or of the physiological age of cells.
Mechanism for Regulating the Distribution of Glucose Carbon Between the Embden-Meyerhof and Hexose-Monophosphate Pathways in
Streptococcus faecalis
Authors: Brown Albert T. , Wittenberger Charles L.
Published: January 2020

Glucose-adapted
Streptococcus faecalis
produced little if any
14
CO
2
from glucose-
1
-
14
C
, although high levels of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44) were detected in cell-free extracts. Metabolism of glucose through the oxidative portion of the hexose-monophosphate pathway was shown to be regulated in this organism by the specific inhibitory interaction of the Embden-Meyerhof intermediate, fructose-1, 6-diphosphate (FDP), with 6-phosphogluconate dehydrogenase. Glucose-6-phosphate dehydrogenase activity was unaffected by FDP. The
S. faecalis
6-phosphogluconate dehydrogenase was partially purified from crude extracts by standard fractionation procedures and certain kinetic parameters of the FDP-mediated inhibition were investigated. The negative effector was shown to cause a decrease in
V
max
and an increase in the apparent
K
m
for both 6-phosphogluconate and nicotinamide adenine dinucleotide phosphate (NADP). These effects were apparently a consequence of the ligand interacting with the enzyme at a site distinct from either the substrate or the coenzyme sites. Among the evidence supporting this was the fact that β-mercaptoethanol blocked completely FDP inhibition, but had no effect on catalytic activity. The possibility that the regulation of 6-phosphogluconate dehydrogenase activity by FDP might be of some general significance was suggested by the observation that this enzyme from several other sources was also sensitive to FDP.
Regulation of Sugar Transport in
Neurospora crassa
Authors: Schneider R. P. , Wiley W. R.
Published: January 2020

Sugar uptake systems in
Neurospora crassa
are catabolically repressed by glucose. Synthesis of a low
K
m
glucose uptake system (system II) in
Neurospora
is derepressed during starvation for an externally supplied source of carbon and energy. Fasting also results in the derepression of uptake systems for fructose, galactose, and lactose. In contrast to the repression observed when cells were grown on glucose, sucrose, or fructose, system II was not repressed by growth on tryptone and casein hydrolysate. System II was inactivated in the presence of 0.1
m
glucose and glucose plus cycloheximide but not by cycloheximide alone. Inactivation followed first-order kinetics with a half-time of 40 min. The addition of glycerol to the uptake medium had no significant effect on the kinetics of 3-0-methyl glucose uptake, suggesting that the system was not feedback inhibitable by catabolites of glycerol metabolism.
Thiosulfate Reductase of
Desulfovibrio vulgaris
Authors: Haschke Richard H. , Campbell L. Leon
Published: January 2020

The thiosulfate reductase of
Desulfovibrio vulgaris
has been purified and some of its properties have been determined. Only one protein component was detected when the purified enzyme was subjected to polyacrylamide gel electrophoresis at
p
H values of 8.9, 8.0, and 7.6. In the presence of H
2
, the enzyme, when coupled to hydrogenase and with methyl viologen as an electron carrier, catalyzed the reduction of thiosulfate to hydogen sulfide. The use of specifically labeled
35
S-thiosulfate revealed that the outer sulfur atom was reduced to sulfide and the inner sulfur atom was released as sulfite. Thus, the enzyme catalyzes the reductive dismutation of thiosulfate to sulfide and sulfite. The molecular weight of the enzyme was determined by sedimentation equilibrium (16,300) and amino acid analysis (15,500). The enzyme sedimented as a single, symmetrical component with a calculated sedimentation coefficient of 2.21
S
. Amino acid analysis revealed the presence of two half-cystine residues per mole of enzyme and a total of 128 amino acid residues. Carbohydrate and organic phosphorus analyses revealed the presence of 9.2 moles of carbohydrate and 4.8 moles of phosphate per mole of enzyme. The substrate specificity of the enzyme was studied.
Surface Structure of
Chromatium okenii
and
Chromatium weissei
Authors: Hageage G. J. , Gherna R. L.
Published: January 2020

The outermost structured layer of both
Chromatium weissei
and
C. okenii
is composed of a hexagonal array of hollow cone-shaped subunits approximately 25 nm in length and 13 nm in diameter.
Low-Level Reading of the UGA Triplet in
Salmonella typhimurium
Authors: Ferretti Joseph J.
Published: January 2020

Evidence indicating low-level reading of the UGA triplet was obtained for six strains of
Salmonella typhimurium
. Such low-level UGA “suppression” may be a general phenomenon common to strains of
S. typhimurium
and, perhaps, to all enteric bacteria.
Non-Essentiality of the
recA
−
Mutation in the Phenomenon of Bacteriophage M13-Induced Elimination of F′ Factors
Authors: Palchoudhury S. R. , Iyer V. N.
Published: January 2020

The elimination of F′ factors promoted by coliphage M13 infection can occur in
recA
+
as well as
recA
−
merodiploid strains of
Escherichia coli
K-12.
Homology of Ribosomal Ribonucleic Acid of
Desulfovibrio
Species with
Desulfovibrio vulgaris
Authors: Pace B. , Campbell L. Leon
Published: January 2020

Three species of
Desulfovibrio
were found to have a high degree of ribosomal ribonucleic acid homology with
Desulfovibrio vulgaris. Desulfotomaculum nigrificans
, which is also a sulfate-reducing anaerobe, had only 38% ribosomal ribonucleic acid homology with
D. vulgaris
. The homologies of six other unrelated genera were determined and found to be lower than 50%.
Promoter-Like Mutant with Increased Expression of the Glycerol Kinase Operon ofEscherichia coli
Authors: Berman-Kurtz Myra , Lin E. C. C. , Richey David P.
Published: January 2020

A glycerol-specific phenotypic revertant isolated from a mutant ofEscherichia colimissing enzyme I of the phosphoenolpyruvate phosphotransferase system was studied. This revertant is capable of producing higher levels of glycerol kinase and the protein mediating the facilitated diffusion of glycerol (facilitator) than wild-type cells. The kinase of the revertant is indistinguishable from the wild-type enzyme with respect to its sensitivity to feedback inhibition by fructose-1,6-diphosphate, itspH optimum, and its turnover number. The synthesis of glycerol kinase in strains bearing the suppressor locus is resistant to catabolite repression. The suppressor mutation mapped at the knownglpKlocus. Thus, it is suggested that the mutation occurred in the promoter of the operon specifying the kinase and the facilitator.
Comparison of the Phospholipid Composition of
Bifidobacterium
and
Lactobacillus
Strains
Authors: Exterkate F. A. , Otten B. J. , Wassenberg H. W. , Veerkamp J. H.
Published: January 2020

Phospholipid composition of 10
Bifidobacterium
strains of human intestinal origin and of 9
Lactobacillus
strains was determined by quantitative two-dimensional thin-layer chromatography. Phospholipids of three
Bifidobacterium
strains from honey bees and of two strains from bovine rumen liquor were qualitatively investigated. Diphosphatidylglycerol and phosphatidylglycerol were present in strains of both genera. All
Bifidobacterium
strains contained as specific phospholipids a new polyglycerolphospholipid, compound 15, and its lyso derivatives, earlier detected in
B. bifidum
var. pennsylvanicus. Also, lyso compounds of diphosphatidylglycerol and alanyl phosphatidylglycerol were only present in this genus in variable amounts. Lysyl phosphatidylglycerol was the only ninhydrin-positive phospholipid in seven
Lactobacillus
strains. In
L. delbrückii
and
L. helveticus
it was absent and partially replaced by an unidentified ninhydrin-negative phospholipid. The differences in phospholipid composition between bifidobacteria and lactobacilli may be another argument to differentiate these two genera.
Modification of the Composition and Structure of the Yeast Cell Wall by Culture in the Presence of Sulfur Amino Acids
Authors: Killick K. A.
Published: January 2020

Growth of
Candida utilis
and
Saccharomyces cerevisiae
in a medium supplemented with sulfur amino acids led to synthesis and accumulation of
S
-adenosylmethionine, accompanied by a reduction in the cell yield, an increased sensitivity of the cell wall to snail gut enzymes (
Helix pomatia
), as judged by spheroplast formation, and by a modification of the chemical composition of both the intact cells and their isolated walls. Walls of supplemented cultures of
C. utilis
were three times as sensitive to enzymatic digestion as walls from nonsupplemented cultures. In contrast to
C. utilis
, walls isolated from supplemented cultures of
S. cerevisiae
were digested slightly more rapidly by the purified snail extract than those from nonsupplemented cultures. Chemical modifications of the cell wall are interpreted to explain the ease with which cells from sulfur amino acid-supplemented cultures are converted to spheroplasts.
Cell Wall Composition of the Yeastlike and Mycelial Forms of
Blastomyces dermatitidis
Authors: Kanetsuna Fuminori , Carbonell Luis M.
Published: January 2020

The thermally induced changes in the cell wall polysaccharides of
Blastomyces dermatitidis
strain BD64, which produces a yeastlike form (Y form) at 37 C and a mycelial form (M form) at 20 C, were examined. The cell walls of the Y and M forms contained 36 and 51% of hexoses, respectively. The M-form cell wall contained glucose, galactose, and mannose in a molar ratio of 1:0.1:0.2. The Y-form cell wall contained mainly glucose and a very small amount of galactose and mannose. The glucans of the cell wall of the Y form consisted of about 95% α-glucan and 5% β-glucan, whereas those of the M-form cell wall consisted of about 60% α-glucan and 40% β-glucan.
Precursor Ribosomal Ribonucleic Acid and Ribosome Accumulation In Vivo During the Recovery of
Salmonella typhimurium
from Thermal Injury
Authors: Tomlins Richard I. , Ordal Z. John
Published: January 2020

When cells of
S. typhimurium
were heated at 48 C for 30 min in phosphate buffer (
p
H 6.0), they became sensitive to Levine Eosin Methylene Blue Agar containing 2% NaCl (EMB-NaCl). The inoculation of injured cells into fresh growth medium supported the return of their normal tolerance to EMB-NaCl within 6 hr. The fractionation of ribosomal ribonucleic acid (rRNA) from unheated and heat-injured cells by polyacrylamide gel electrophoresis demonstrated that after injury the 16
S
RNA species was totally degraded and the 23
S
RNA was partially degraded. Sucrose gradient analysis demonstrated that after injury the 30
S
ribosomal subunit was totally destroyed and the sedimentation coefficient of the 50
S
particle was decreased to 47
S
. During the recovery of cells from thermal injury, four species of rRNA accumulated which were demonstrated to have the following sedimentation coefficients: 16, 17, 23, and 24
S
. Under identical recovery conditions, 22, 26, and 28
S
precursors of the 30
S
ribosomal subunit and 31 and 48
S
precursors of the 50
S
ribosomal subunit accumulated along with both the 30 and 50
S
mature particles. The addition of chloramphenicol to the recovery medium inhibited both the maturation of 17
S
RNA and the production of mature 30
S
ribosomal subunits, but permitted the accumulation of a single 22
S
precursor particle. Chloramphenicol did not affect either the maturation of 24
S
RNA or the mechanism of formation of 50
S
ribosomal subunits during recovery. Very little old ribosomal protein was associated with the new rRNA synthesized during recovery. New ribosomal proteins were synthesized during recovery and they were found associated with the new rRNA in ribosomal particles. The rate-limiting step in the recovery of
S. typhimurium
from thermal injury was in the maturation of the newly synthesized rRNA.
Boticinogeny and Actions of the Bacteriocin
Authors: Anastasio Kathryn L. , Soucheck J. A. , Sugiyama H.
Published: January 2020

The bacteriocin, boticin E, was produced by only a few strains of those clostridia which are nontoxigenic but otherwise identical to
Clostridium botulinum
type E. Boticin preparations from four different strains had identical spectra against indicator cultures. Experiments with bacterial lawns showed boticin to be sporostatic for all tested nonproteolytic
C. botulinum
(types B, E, and F) and nontoxigenic type E-related strains which included the producing strains as well as those different from type E in the fermentation of one to three carbohydrates. Boticin had no detectable effect on vegetative cells of boticinogenic strains but killed those of all other strains whose spores were sensitive. Cultures that were growing in an agar medium were more sensitive to the bacteriocin than those growing in broth. Vegetative cells of indicator strains adsorbed boticin, but cells of a boticin-resistant mutant did not. Boticin did not lyse suspensions of vegetative cells which had been killed previously by exposure to air but lysed actively growing protoplasts and L-forms of a strain whose normal vegetative cells are susceptible to lysis. Sporostasis resulted from inhibition of germination rather than of outgrowth. Proteolytic strains of
C. botulinum
(types A, B, and F) were resistant to boticin E.
Nature and Origins of Phosphorus Compounds in Isolated Cell Walls of
Staphylococcus aureus
Authors: Mirelman David , Shaw D. R. D. , Park James T.
Published: January 2020

Preparations of purified cell walls from
Staphylococcus aureus
were shown to contain small amounts of phospholipid and glycerol teichoic acid. Since these are components of the cell membrane, it is probable that the wall itself contains no lipid, but does retain fragments of membrane because of physical connections between wall and membrane. In walls of
S. aureus
strain 52A5, which completely lacks ribitol teichoic acid, the only phosphorylated compound identified as a genuine wall component was a phosphorylated derivative of murein that gave rise to muramic acid phosphate on acid hydrolysis. Muramic acid phosphate was also identified in hydrolysates of walls from
S. aureus
H and strain 52A2.
Effect of Shift-Down and Growth Inhibition on Phospholipid Metabolism of
Escherichia coli
Authors: Ballesta J. P. G. , Schaechter M.
Published: January 2020

The metabolism of phospholipids of
Escherichia coli
was studied under conditions which inhibit various metabolic processes. Phospholipid synthesis and turnover were not inhibited by growth-inhibitory amounts of various antibiotics. Turnover of phosphatidylglycerol (PG) was inhibited by small amounts of dinitrophenol and by anaerobiosis. Turnover of phosphatidylethanolamine (PE), which is not detected in control cultures, was demonstrated under conditions of incipient lysis. When cells were shifted down from a rich to a poor medium, PE synthesis was inhibited, and incorporation of glycerol into the distal position of PG was stimulated. Under these conditions, turnover of the phosphate and the acylated glycerol moieties of PG was inhibited. Increased synthesis of PE was detected when filamentous cells were induced to make septa. The results indicate that PE synthesis is related to growth and cell division, whereas PG metabolism is related to other cell processes.
Polynucleotide Sequence Relationships Among Some Bacterial Plasmids
Authors: Guerry Patricia , Falkow Stanley
Published: January 2020

The deoxyribonucleic acid of F-like plasmids appear to share a high degree of nucleotide similarity with each other but are not highly related to I-like plasmids.
Deoxyribonucleic Acid Hybridization Among Strains of Lactobacilli
Authors: Simonds Josephine , Hansen P. Arne , Lakshmanan Sitarama
Published: January 2020

Hybridization of deoxyribonucleic acid (DNA) from
Lactobacillus bulgaricus
(ATCC 11842) with DNA of
L. lactis
(ATCC 12315),
L. helveticus
(ATCC 15009), and
L. jugurt
(ATCC 521) showed 86.0% reassociation with
L. lactis
, 4.8% with
L. helveticus
, and none with
L. jugurt
.
Kinetics of Exogenous Induction of the Hexose-6-Phosphate Transport System of
Escherichia coli
Authors: Winkler Herbert H.
Published: January 2020

The kinetics of the exogenous induction of the hexose-phosphate transport system by glucose-6-phosphate (G6P) was investigated. The induction of this system by extracellular but not intracellular G6P was confirmed. The differential rate of synthesis was linear, a function of the extracellular concentration of G6P and independent of the previous induction history of the culture. Neither maintenance nor autocatalysis, phenomena described in the induction of the
lac
operon, were observed in the exogenous induction of hexose-phosphate transport. Fructose-6-phosphate, a potent competitive inhibitor of G6P influx, had no effect on the induction of the system by G6P, indicating that the transport of inducer was not involved in the induction process.
Staphylococcal Bacteriophage-Associated Lysin: a Lytic Agent Active Against
Staphylococcus aureus
Authors: Sonstein Stephen A. , Hammel Jay M. , Bondi Amedeo
Published: January 2020

A lytic enzyme active against viable, intact staphylococci is released into culture fluids upon lysis of bacteriophage-infected
Staphylococcus aureus
PS53 cells. This enzyme, staphylococcal phage-associated lysin (PAL), was partially purified by ammonium sulfate precipitation and gel filtration through Sephadex G-200. PAL is optimally active at
p
H 6.5 and 30 C, and lytic activity is greatly enhanced by the addition of reducing agents. Lytic activity was observed against all strains of staphylococci tested and against purified staphylococcal cell walls, but no activity was noted against other bacterial species. PAL possesses peptidase activity and results in the production of spheroplasts which can be osmotically stabilized for extended periods by the addition of 7.5% polyethylene glycol 4000.
Hydrogenation of Unsaturated Fatty Acids by
Treponema
(
Borrelia
) Strain B
2
5, a Rumen Spirochete
Authors: Yokoyama M. T. , Davis C. L.
Published: January 2020

The time course of hydrogenation of linoleic acid to
trans
-11-octadecenoic acid was observed in a growing culture of
Treponema
(
Borrelia
) strain B
2
5. A conjugated fatty acid,
cis
-9,
trans
-11-octadecadienoic acid, was identified as an intermediate in the process. The isomerase responsible for the conversion of linoleic acid to the conjugated fatty acid was found to be associated with a particulate fraction characterized by a high protein and lipid content in a 2:1 ratio. Optimum
p
H for isomerase activity was found to be 7.0 in 0.05
m
potassium phosphate buffer. No cofactor requirements could be demonstrated for the isomerase. The sulfhydryl inhibiting agents, iodoacetamide,
N
-ethylmaleimide, and
p
-chloromercuribenzoate, inhibited isomerase activity. Isomerase activity was also inhibited by the metal chelators,
o
-phenanthroline, α, α′-bipyridyl, ethylenediaminetetraacetic acid, and 8-hydroxyquinoline. Linoleic (Δ9, 12), linolenic (Δ9, 12, 15), and gamma-linolenic (Δ6, 9, 12) acids served as effective substrates for the isomerase; however, the derivatives of linoleic and linolenic acid did not.
Characterization of the A Component ofStreptococcus zymogenesLysin
Authors: Granato Paul A. , Jackson Robert W.
Published: January 2020

By utilizing conventional techniques of pressure ultrafiltration, gel filtration chromatography, diethylaminoethyl cellulose chromatography, and preparative polyacrylamide electrophoresis, the A component of the group D lysin produced byStreptococcus zymogeneshas been purified to a state of apparent homogeneity when determined by the techniques of anionic and cationic disc gel electrophoresis. The A component was found to be a protein possessing a molecular weight of 27,000, a sedimentation coefficient approximating 3.2S, and a net negative charge at physiologicalpH.
Folate Replacement by Tetrahydrohomopteroate in Triazine-Resistant Bacteria
Authors: Genther Clara S. , Roszmann John H. , Smith Carl C. , Kisliuk Roy L.
Published: January 2020

Tetrahydrohomopteroate, which inhibits the growth of
Streptococcus faecium
(
Streptococcus faecalis
ATCC 8043), replaces folate as a growth factor in chlorguanide triazine-resistant strains of this organism.
Ribonucleic Acid Synthesis in Bacteria Treated with Toluene
Authors: Peterson R. L. , Radcliffe C. W. , Pace N. R.
Published: January 2020

Escherichia coli
and
Bacillus megaterium
rendered permeable to ribonucleoside triphosphates by toluene treatment retain the capacity to synthesize discrete ribonucleic acid species.
Asymmetric Template Function of Microbial Deoxyribonucleic Acids: Transcription of Messenger Ribonucleic Acid
Authors: Margulies Lola , Remeza Virgilija , Rudner Rivka
Published: January 2020

In
Bacillus subtilis
and
Escherichia coli
, pulse-labeled ribonucleic acid (RNA) synthesized during step-down growth hybridized preferentially with the heavy (H) strand of methylated albumin-Kieselguhr-fractionated deoxyribonucleic acid (DNA). At high RNA inputs, the ratio of RNA hybridized with the H strand to that hybridized with the light (L) strand was 8.7 for
B. subtilis
and 2.0 for
E. coli
. At high DNA inputs, the H/L hybridization ratio increased by a factor of two. This change in the hybridization ratio was attributable to the fraction of the pulse-labeled RNA which is in stable RNA components. The hybridization peak of pulse-labeled RNA was specifically located in the late-eluting region of the absorbance profile of the H strand. This region was considered to represent the most actively transcribing H strand templates.
Glucose and Fructose Metabolism in a Phosphoglucoisomeraseless Mutant of
Saccharomyces cerevisiae
Authors: Maitra P. K.
Published: January 2020

A mutant of
Saccharomyces cerevisiae
deficient in phosphoglucoisomerase (EC 5.3.1.9) is described. It does not grow on glucose or sucrose but does grow on galactose or maltose. Addition of glucose to cultures growing on fructose, mannose, or acetate arrests further growth without altering viability; removal of glucose permits resumption of growth. Glucose causes accumulation of nearly 30 μmoles of glucose-6-phosphate per g (wet weight) of cells and suppresses synthesis of ribonucleic acid. Inhibition of growth by glucose does not appear to be due to a loss of adenosine triphosphate or inorganic orthophosphate. The mutant, however, utilizes glucose-6-phosphate produced intracellularly. Release of carbon dioxide from specifically labeled glucose suggests a C-l preferential cleavage. The kinetics of glucose-6-phosphate accumulation during glucose utilization in the mutant is not consistent with the notion that the utilization of glucose is controlled by glucose-6-phosphate.
Phospholipid Metabolism in the Absence of Net Phospholipid Synthesis in a Glycerol-Requiring Mutant of
Bacillus subtilis
Authors: Lillich Thomas T. , White David C.
Published: January 2020

A glycerol-requiring auxotroph of
Bacillus subtilis
showed no net synthesis of phospholipid when deprived of glycerol. Although there was no net synthesis of phospholipid, we found that: (i) fatty acids and
32
P were slowly incorporated into phospholipid; (ii) in pulse-chase experiments, both
32
P and
14
C in the glycerol portion of the phospholipids were lost from phosphatidlyglycerol (PG) and lysylphosphatidylglycerol and accumulated in cardiolipin (CL); (iii) the proportions of the phospholipids in the membrane changed with a loss of PG and an accumulation of CL. The addition of glycerol to the glycerol-deprived cells resulted in a rapid incorporation of glycerol and restoration to the predeprivation metabolism and PG to CL ratio.
Distribution and Correlation of Events During Thermal Inactivation of
Bacillus megaterium
Spores
Authors: Levinson Hillel S. , Hyatt Mildred T.
Published: January 2020

Aqueous suspensions of
Bacillus megaterium
QM B1551 spores were heated at temperatures from 75 to 85 C. The rapid initial viability loss, followed by a more gradual, almost exponential decline, was not due to mixed populations with discrete heat resistances. The slight “tailing” below 0.01% survival was not the result of heat adaptation. Loss of viability was more rapid than loss of dipicolinic acid (DPA) and germinability and, although these events could not be correlated by use of simple kinetic plots, they had similar activation energies (80 to 90 kcal/mole). Probability (probit) plots of per cent survival as a function of logarithmic time yielded not the single line expected, if the heat resistances of individuals in the population were log-normally distributed, but two straight lines intersecting at a survival level of 1 to 6%. Probit-intersects occurred at times ranging from 8 min for spores heated at 85 C, to 310 min at 75 C. Probit-intersects for DPA release and loss in germinability occurred at the same time as for survival, but at much higher levels of retention. There appeared to be two subpopulations, both log-normally distributed but with different mechanisms of kill. Ninety-four to 99% of the spores died via injury to the cell-division process but retained germinability; the remaining smaller subpopulation (1 to 6%) was nonviable because of loss of the ability to germinate.
Regulation and Self-Inhibition ofMicrosporum gypseumMacroconidia Germination
Authors: Page W. J. , Stock J. J.
Published: January 2020

Germination ofMicrosporum gypseummacroconidia was accompanied by the release of alkaline protease, calcium ions, and inorganic phosphate into the germination fluid. The rate of germination was greatest during the first 2 hr, decreasing thereafter. This decrease in rate was accompanied by a decrease in protease activity, which was caused by an interaction of the enzyme with the inorganic phosphate released from the spores and accumulated in the germination medium after 2 hr. Germination of high spore densities was regulated by the ratio of released phosphate to protease protein, resulting in a constant percentage of germination at both high and low spore densities. A germination-defective mutant strain failed to germinate normally and released excessively high concentrations of phosphate into the germination medium during the initial 2 hr of incubation. Addition of calcium ions to germination mutant macroconidia stabilized spore morphology, prevented protease inactivation, and allowed normal germ-tube outgrowth. The germination of macroconidia appears to be regulated by the release of phosphate ions, which then inhibit the alkaline protease.
Mode of Action of Zorbamycin
Authors: Reusser Fritz
Published: January 2020

Zorbamycin (U-30,604E) induces rapid degradation of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) in
Bacillus subtilis
cells. DNA degradation is initiated first and is closely followed by the degradation of RNA. No interaction between isolated DNA and zorbamycin is observed. Nucleic acid and protein syntheses are not inhibited by zorbamycin in cell-free systems. Since the initial effect of the antibiotic is expressed at the level of the cellular DNA fraction, we assume that zorbamycin somehow induces a change in the structure or function of the cellular DNA fraction which results in rapid breakdown of this fraction.
Histidine Regulation in
Salmonella typhimurium
VIII. Mutations of the
hisT
Gene
Authors: Chang George W. , Roth John R. , Ames Bruce N.
Published: January 2020

The
hisT
gene, one of six genes in which mutation causes derepression of the histidine operon in
Salmonella typhimurium
, is shown to code for a protein that is not essential for the growth of the bacteria. This is indicated by the characterization of particular classes of mutations in the
hisT
gene: amber mutations, frame-shift mutations, and temperature-sensitive mutations that affect repression but not growth. In addition, the class of semilethal mutations was selected for but not found.
Pseudomonas putida
Tryptophan Synthetase
Authors: Enatsu Toshio , Crawford Irving P.
Published: January 2020

The two protein components of
Pseudomonas putida
tryptophan synthetase have been purified to homogeneity. Although there is general similarity between the
Pseudomonas
enzyme and that of the enteric bacteria, many differences were found. Components from
Escherichia coli
and
P. putida
do not stimulate each other enzymatically, and the enzymes differ in their response to monovalent cations. Serine deamination occurs best with the intact enzyme of
P. putida
, not with the β
2
subunit alone as in
E. coli
. The amino acid compositions of the α subunits differ appreciably. These findings extend earlier studies showing differences between enteric organisms and pseudomonads in the regulation and genetic organization of the enzymes of the tryptophan pathway.
Reconstitution of Bacterial Spore Coat Layers In Vitro
Authors: Aronson A. I. , Fitz-James P. C.
Published: January 2020

The spore coat layers of
Bacillus cereus
T can be at least partially restored by mixing spores stripped of their coat with solubilized coat protein.
Transport of Glycerol by
Pseudomonas aeruginosa
Authors: Tsay San-San , Brown Karen K. , Gaudy Elizabeth T.
Published: January 2020

In
Pseudomonas aeruginosa
, the transport of glycerol was shown to be genetically controlled and to be dependent on induction by glycerol. Accumulation of
14
C-glycerol was almost completely absent in uninduced cells and in a transport-negative mutant. Kinetic studies with induced cells suggested that glycerol may be transported by two systems with different affinities for glycerol. Osmotically shocked cells did not transport glycerol, and the supernatant fluid from shocked cells contained glycerol-binding activity demonstrable by equilibrium dialysis. The binding protein was not glycerol kinase. Binding activity was absent in shock fluids from the transport-negative mutant and from uninduced cells. The glycerol-binding protein was partially purified by precipitation with ammonium sulfate. Mild heat treatment completely eliminated the binding activity of shock fluid and of the partially purified protein. Sodium azide and
N
-ethylmaleimide inhibited both transport by whole cells and binding of glycerol by shock fluid. It is concluded that transport of glycerol by
P. aeruginosa
involves a binding protein responsible for recognition of glycerol and may occur by facilitated diffusion or active transport. A requirement for energy has not been demonstrated.
Fate of Transforming Deoxyribonucleate in
Bacillus subtilis
Authors: Piechowska Miroslawa , Fox Maurice S.
Published: January 2020

The majority of donor deoxyribonucleate (DNA) at early stages after uptake was found in a complex with a cell component which changes its buoyant behavior on equilibrium density gradients. Analysis of the recipient cell lysates, after treatment to dissociate the complex, showed about two-thirds of the donor molecules in denatured form and the rest associated with recipient DNA. Incubation of cells after DNA uptake leads to the disappearance of denatured donor DNA and to the increase of donor label associated with recipient DNA. Some characteristics of a component from intact cells or spheroplasts with affinity for denatured
Bacillus subtilis
DNA are described.