bluuebunny/crossref_metadata_2025 huggingface dataset:
Lipopolysaccharide Layer Protection of Gram-Negative Bacteria Against Inhibition by Long-Chain Fatty Acids
Authors: Sheu Chingju W. , Freese Ernst
Published: January 2020

Growth, amino acid transport, and oxygen consumption of
Escherichia coli
and
Salmonella typhimurium
are inhibited by short-chain (C
2
-C
6
) but not by medium or long-chain fatty acids (C
10
-C
18
) at concentrations at which these processes are completely inhibited in
Bacillus subtilis
. The resistance of gram-negative organisms is not correlated with their ability to metabolize fatty acids, since an
E. coli
mutant unable to transport oleic acid is still resistant. However, mutants of both
E. coli
and
S. typhimurium
in which the lipopolysaccharide layer does not contain the residues beyond the 2-keto-3-deoxyoctonate core are inhibited by medium (C
10
) but not by long-chain (C
18
) fatty acids. Furthermore, removal of a portion of the lipopolysaccharide layer by ethylenediaminetetraacetate treatment renders the organisms sensitive to medium and partially sensitive to long-chain fatty acids. The intact lipopolysaccharide layer of gram-negative organisms apparently screens the cells against medium and long-chain fatty acids and prevents their accumulation on the inner cell membrane (site of amino acid transport) at inhibitory concentrations. These results are relevant to the use of antimicrobial food additives, and they allow the characterization of gram-positive versus gram-negative bacteria and their lipopolysaccharide mutants.
Cross-Feeding of
Escherichia coli
Mutants Defective in the Biosynthesis of Nicotinamide Adenine Dinucleotide
Authors: Kerr Thomas J. , Tritz Gerald J.
Published: January 2020

Mutants of
Escherichia coli
defective in the biosynthesis of nicotinamide adenine dinucleotide (NAD) are able to grow in a Casamino Acids medium lacking NAD and its immediate precursors, nicotinic acid and nicotinamide. This property has allowed the development of a system to measure cross-feeding between a
nadA
and a
nadB
mutant. This system provides a means of isolating the intermediate, prequinolinic acid, as well as a biological assay for the compound. The
nadB
mutant feeds the
nadA
mutant, indicating that the
nadA
enzyme occurs first in the pathway and the
nadB
enzyme second. No cross-feeding was detected between
nadA
and
nadC
or between
nadB
and
nadC
.
Energy Coupling of the Hexose Phosphate Transport System in
Escherichia coli
Authors: Winkler Herbert H.
Published: January 2020

The active transport of hexose phosphates in
Escherichia coli
was inhibited by many uncouplers or inhibitors of oxidative metabolism. Fluoride and the lipid soluble cation, triphenylmethylphosphonium, had little effect. The uninduced level of transport was sensitive to fluoride, but not to azide. After energy uncoupling of active transport, the cells could equilibrate their intracellular water with the glucose-6-phosphate in the medium and displayed exit counter-flow suggesting the existence of carrier-mediated transport in the energy-uncoupled cells. The uncoupled transport of glucose-6-phosphate was inhibited by fructose-6-phosphate; the uninduced level of glucose-6-phosphate transport was not inhibited by fructose-6-phosphate. After energy uncoupling, the influx had a low affinity suggesting that, unlike the transport of β-galactosides, the energy coupling for the active transport of hexose phosphate involved a change in the affinity of influx.
Inhibition of Yeast Ribonucleic Acid Polymerases by Thiolutin
Authors: Tipper D. J.
Published: January 2020

Yeast ribonucleic acid (RNA) polymerase II, isolated after fractionation on diethylaminoethyl (DEAE)-cellulose (DE-52) or on DEAE-Sephadex (A-25), is 50% inhibited by 1.5 μg of α-amanitin. This inhibition is independent of the sequence of interaction of enzyme, template, nucleotides, and antibiotic and is expressed immediately on addition of α-amanitin to a preparation actively synthesizing RNA. Thus, α-amanitin's primary effect is inhibition of elongation of preinitiated RNA sequences in this system, as in others. A single peak of α-amanitin-resistant RNA polymerase activity (I) was eluted before enzyme II on either column. On A-25 but not on DE-52, a third peak of activity (III) was eluted after enzyme II. This activity was also resistant to α-amanitin. Enzymes I, II, and III were 50% inhibited by 3, 4, and 3 μg of thiolutin per ml, respectively. The extent of inhibition was independent of the nature of the template (native or denatured salmon sperm deoxyribonucleic acid or poly(dA-dT) or of the presence of 0.4 mM dithiothreitol, but this marked inhibition was only seen when enzymes were preincubated with thiolutin in the absence of template. Template protected the enzymes against thiolutin in the absence of nucleotides. Either the sensitive site on the polymerase is only accessible to thiolutin before interaction with template or thiolutin inhibits functional polymerase-template interaction but not elongation of preinitiated RNA chains.
Appearance of a Ribonucleic Acid Polymerase-Binding Protein in Asporogenous Mutants of
Bacillus subtilis
Authors: Greenleaf Arno L. , Losick Richard
Published: January 2020

A 70,000-dalton protein that is found in sporulating
Bacillus subtilis
and that binds to ribonucleic acid polymerase is present in asporogenous mutants that proceed to or beyond stage II of sporulation, but is absent from mutants blocked at stage zero.
Lysis of
Escherichia coli
by Glycine Is Potentiated by Pyridoxine Starvation
Authors: Dempsey Walter B.
Published: January 2020

Pyridoxineless mutants of
Escherichia coli
are lysed in a few hours when starved for pyridoxine in a glucose minimal medium containing glycine at 10 mM. The lysis is prevented equally well by
l
-alanine and by
d
-alanine when either is present at 0.1 mM. The lysis is potentiated by 0.5 mM
l
-methionine. The peculiar susceptibility of
E. coli
B to glycine-mediated lysis during starvation for pyridoxine suggests that the starvation reduces the availability of some normal antagonist of glycine, presumably alanine.
Isolation of a Suppressor Host Bacterium in
Staphylococcus aureus
Authors: Kretschmer P J. , Egan J. Barry
Published: January 2020

A bacterial mutant of
Staphylococcus aureus
NCTC 8325 has been isolated which has the properties of a suppressor host mutant. The mutant was isolated as a one-step phenotypic revertant to wild type of a strain containing mutations in two unlinked markers concerned with metabolism of lactose via the phosphoenol pyruvate-dependent phosphotransferase system. The revertant (called
sup1
+
) has been used to isolate seventy conditional lethal mutants of the phage O11. The phage mutants, which plate on
sup1
+
but not on the original 8325 strain, have been assigned by complementation studies into 10 groups. It is probable that this technique for the isolation of suppressor hosts would be applicable to other
Staphylococcus
strains.
Influence of Thymine Starvation on the Integrity of Episomal and Chromosomal Deoxyribonucleic Acids in
Escherichia coli
CR34 (λ
ind
−
)
Authors: Shuster Robert C.
Published: January 2020

The effect of thymine deprivation on the integrity of phage λ, sex factor, and chromosomal deoxyribonucleic acid (DNA) in
Escherichia coli
CR34 (λ
ind
−
) was examined by sedimenting cell lysates through alkaline sucrose gradients. Both sex factor and chromosomal DNAs showed evidence of being degraded during the starvation period. In contrast, no loss of closed circular λ DNA was observed.
Trehalose Metabolism in Germinating Spores of
Streptomyces hygroscopicus
Authors: Hey-Ferguson Ann , Mitchell Mike , Elbein A. D.
Published: January 2020

Evidence is presented which indicates that utilization of trehalose is an early event in spore germination in
Streptomyces hygroscopicus
. Early in spore germination and before any increase in cell mass, the activity of trehalase increased more than 15-fold, while the intracellular content of trehalose fell to very low levels. On the other hand, increased activity of the trehalose phosphate synthetase or disappearance of glycogen did not occur until later in germination, during which time cell mass was also increasing.
Regulation of Cell Division in a Temperature-Sensitive Division Mutant of
Escherichia coli
Authors: Stone A. B.
Published: January 2020

Escherichia coli fil ts
forms multinucleate filaments when suspensions of about 10
7
organisms per ml are shifted from 37 to 43 C in rich medium. Occasional septation continues, chiefly at the poles, and immediately becomes more frequent when the filaments are returned to 37 C. The addition of chloramphenicol (200 μg/ml) at either temperature initially stimulates the formation of polar septa. When very dilute suspensions of the strain (<10
6
organisms per ml) are shifted to the restrictive temperature, the inhibition of septation is more complete and only seldom reversible. Conversely, cell division is little affected when suspensions of >10
8
organisms per ml, or microcolonies of several hundred organisms on agar, are incubated at 43 C; evidence is presented that this is a consequence of a slight reduction in the mutant's growth rate. In certain media, septation is blocked irreversibly by even brief exposure to 43 C, after which cell elongation without division proceeds at 37 C for some hours. Several findings, when considered together, suggest that the cytoplasmic membrane is normal at the restrictive temperature, and that the block in septation is caused by a defect in the cell wall: it is largely overcome by NaCl, but not by sucrose; in some circumstances the filaments become swollen and develop localized bulges in the wall, yet the membrane remains intact and retains its selective permeability; lastly, the strain is insensitive to deoxycholate at both temperatures. The mutation has been mapped between
arg B
and
thr
, at a locus which appears to be distinct from others known primarily to influence cell division.
Poly-β-Hydroxybutyrate Metabolism During Growth and Sporulation of
Clostridium botulinum
Authors: Emeruwa A. C. , Hawirko R. Z.
Published: January 2020

The granules observed in the cytoplasm of cells of sporogenic and asporogenic strains of
Clostridium botulinum
type E were isolated at various developmental stages of growth and sporulation. Electron microscopy of thin sections showed that most of the granules were dispersed throughout the cytoplasm. Chemical analysis and electron microscopy showed that the granules were poly-β-hydroxybutyrate (PHB). The polymer began to accumulate after 8 h of growth, reaching 9 and 13% of the cell dry weight in the sporogenic and asporogenic strains, respectively, during early stationary phase.
14
C-acetate was readily incorporated into PHB. The rate of assimilation paralleled the production and utilization of PHB, indicating that the acetate served as its precursor.
14
C-butyric acid was not utilized to any significant extent. Most of the PHB which had accumulated in the sporogenic strain was catabolized during the development of the spore, but in the asporogenic mutant it remained essentially unchanged. The findings suggest that the PHB provides endogenous carbon and energy for the synthesis of spore-specific components required for spore maturation.
Growth and Cloning of
Tetrahymena pyriformis
on Solid Medium
Authors: Gardonio Enore , Crerar Michael , Pearlman Ronald E.
Published: January 2020

A method of obtaining clones of
Tetrahymena pyriformis
on solid medium has been developed. The medium consists of a basal layer of 1.5% agar topped with 2 ml of 0.3% agar in sterile, plastic petri plates (100 by 15 mm). Both agar layers contain either 2% proteose peptone and 0.1% liver extract (complex medium) or defined medium supplemented with proteose peptone. After drying, 0.5 ml of liquid culture is spread evenly over the top agar, and the plates are then sprinkled lightly and evenly with autoclaved dry Sephadex G-25 (fine). Cell colonies can be observed after 5 days of incubation either by viewing with a microscope or without the aid of a microscope after staining. Plating efficiency is high on either complex or defined medium with a number of strains of
Tetrahymena
, both micronucleate and amicronucleate. Colonies can be picked and transferred to liquid culture for further growth. The existence of clones was demonstrated by plating a mixture of two different drug-resistant mutants. The method should prove useful in selective procedures for the isolation of mutants and for determining survival after treatments such as ultraviolet irradiation.
Effect of
cis
-Platinum(II)Diamminodichloride on Wild Type and Deoxyribonucleic Acid Repair-Deficient Mutants of
Escherichia coli
Authors: Beck Doris J. , Brubaker Robert R.
Published: January 2020

The anti-tumor drug
cis
-platinum(II)diamminodichloride (PDD) induced extensive filamentation in wild-type
Escherichia coli
and in mutants lacking certain deoxyribonucleic acid (DNA) repair functions (
uvrA, recB, recC
, and
polA
); viability of repair-deficient mutants treated with PDD was significantly less than that of wild-type cells. PDD was highly toxic to
lex1, lex1 uvrA6
(where its effect was cummulative), and
recA13
mutants, all of which were killed without formation of filaments.
3
H-thymine incorporated into DNA of cells subsequently treated with PDD became trichloroacetic acid-soluble at rates similar to those observed after exposure to comparable doses of ultraviolet light (UV) or mitomycin C. PDD, like UV, induced extensive degradation of DNA in
recA
organisms. After a 30-min lag, PDD inhibited significantly the synthesis of DNA but not of ribonucleic acid or protein in
E. coli
. However, the relative differences between rates of DNA synthesis observed in PDD-treated and control cells decreased substantially when the duration of pulses (
3
H-thymine) was prolonged from 2 to 5 min. These observations suggest that PDD-induced damage to DNA is reversible, possibly by defined mechanisms of excision and recombination repair.
Stringent Control of Intracellular Proteolysis in
Escherichia coli
Authors: Pine Martin J.
Published: January 2020

Regulation of intracellular proteolysis has been compared during amino acid deficiencies in seven double auxotrophs of
Escherichia coli
9723f with a common phenylalanine requirement. Individual deficiencies were either more effective than, less effective, or equal to phenylalanine deficiency in stimulating intracellular proteolysis. For each amino acid, the same relationship prevailed in inhibiting uracil incorporation into nucleic acids, a reaction series regulated by the
rel
gene for stringent control. The three amino acids least abundant in the cellular protein were the least effective regulators. These findings are interpreted as supportive evidence for stringent control of intracellular proteolysis by the
rel
gene.
Action of Ribonuclease T1 on 30
S
Ribosomes of
Escherichia coli
and Its Role in Sequence Studies on 16
S
Ribonucleic Acid
Authors: Santer Melvin , Santer Ursula
Published: January 2020

Two large ribonucleic acid (RNA) fragments have been obtained from T1-RNase-treated 30
S
ribosomes of
Escherichia coli
. One fragment, about 475 nucleotides long, contains all the unique oligonucleotides found by Fellner and associates in sections of 16
S
RNA designated P, E, E′, and K, and one-half the large oligonucleotides of section A. The other large fragment is about 300 nucleotides long and contains the oligonucleotides found in sections C, C′, C″. The isolation of these large fragments seems to confirm the arrangement of sections within 16
S
RNA. There are also recovered from nuclease-treated ribosomes three small fragments, one (120 nucleotides long) from the 5′ end, one (26 nucleotides long) from the 3′ OH end of the chain, and another section (66 nucleotides long) from the middle of the 16
S
RNA chain. Small molecular weight material is also generated by nuclease treatment, and about half this material is derived from a region close to the 3′ OH end of the 16
S
RNA chain. This indicates that the most accessible part of the rRNA of
E. coli
30
S
ribosomes is a region 100 to 150 nucleotides long near the 3′ end of the chain. A general scheme is proposed to explain the generation of the various-sized RNA products from the rRNA of the 30
S
ribosome.
Isolation of the Bacteriophage Lambda Receptor from
Escherichia coli
Authors: Randall-Hazelbauer L. , Schwartz M.
Published: January 2020

A factor which inactivates the phage lambda can be extracted from
Escherichia coli
. This factor is a protein and is located in the outer membrane of the bacterial envelope. It is found in extracts of strains which are sensitive to phage lambda, but not in extracts of strains specifically resistant to this phage. We conclude that this factor is the lambda receptor, responsible for the specific adsorption of the phage lambda to
E. coli
cells. A partial purification of the lambda receptor is described. Inactivation of the phage by purified receptor is shown to be accompanied by the release of deoxyribonucleic acid from the phage.
Nature of the Genetic Determinant Controlling Exfoliative Toxin Production in
Staphylococcus aureus
Authors: Rogolsky Marvin , Warren Richard , Wiley Bill B. , Nakamura Hanh T. , Glasgow Lowell A.
Published: January 2020

Phage group II
Staphylococcus aureus
has been identified as the etiological agent of the staphylococcal scaleded skin syndrome. The development of an animal model system permitted fulfillment of Koch's postulates and recognition of exfoliative toxin (ET) as being responsible for some of the clinical manifestations of this syndrome. Initial studies directed toward associating a lysogenic phage with the genetic control of ET synthesis failed to support this hypothesis. Growth of two Tox
+
strains at 44 C was more effective than growth in ethidium bromide or sodium dodecyl sulfate in eliminating the ability to produce ET. The early and rapid accumulation of ET-negative (Tox
−
) variants during growth of strain UT 0007 at 44 C, the lack of any selective advantage of the Tox
−
variants over Tox
+
cells during growth at 44 C, and an enhanced elimination frequency at 44 C of 97.9% over the spontaneous frequency of loss strongly suggest that the gene for ET synthesis is extrachromosomal. Additional evidence suggests that this gene is located on a plasmid which is not associated with genes for penicillinase synthesis and cadmium resistance. Two Tox
+
strains harbored lysogenic phage capable of transducing cadmium resistance, but not penicillin resistance, to specific Tox
−
recipients.
Regulation of Maltodextrin Phosphorylase Synthesis in
Escherichia coli
by Cyclic Adenosine 3′, 5′-Monophosphate and Glucose
Authors: Chao Julie , Weathersbee Carolyn J.
Published: January 2020

Cyclic adenosine 3′, 5′-monophosphate (AMP) stimulates maltodextrin phosphorylase synthesis in
Escherichia coli
cells induced with maltose. A maximal effect occurs at 2 to 3 mM cyclic AMP. The action of cyclic AMP is specific, inasmuch as adenosine triphosphate, 3′-AMP, 5′-AMP, adenosine, and dibutyryl cyclic AMP are inactive. Glucose, α-methyl glucoside, 2-deoxyglucose, and pyridoxal 5′-phosphate repress maltodextrin phosphorylase synthesis. This repression is reversed by cyclic AMP. The action of cyclic AMP appears to be at the transcriptional level, since cyclic AMP fails to stimulate phosphorylase production in induced cells in which messenger ribonucleic acid synthesis has been arrested by rifampin or by inducer removal. The two other enzymes involved in the metabolism of maltose, amylomaltase and maltose permease, are also induced in this strain of
E. coli
and affected by glucose and cyclic AMP in a manner similar to phosphorylase.
Induction of Morphogenesis in
Geodermatophilus
by Inorganic Cations and by Organic Nitrogenous Cations
Authors: Ishigura Edward E. , Wolfe R. S.
Published: January 2020

Morphogenesis of
Geodermatophilus
strain 22–68 involves two stages, a motile rod (R form) and an irregularly shaped cluster of coccoid cells (C form). A variety of mono- and divalent cations have been found to induce R-form to C-form morphogenesis and to maintain the organism in the C form. Concentration optima for all cations exceeded 100 mM. Results indicated that uptake of cations was accompanied by extrusion of intracellular protons, causing an increase in intracellular pH. A variety of organic amines also induced morphogenesis. Organic amines were taken up in the dissociated free base form, causing the intracellular pH to rise. None of these compounds was utilized as a carbon or nitrogen source.
malB
Region in
Escherichia coli
K-12: Characterization of New Mutations
Authors: Hofnung Maurice , Hatfield Dolph , Schwartz Maxime
Published: January 2020

Phenotypic characterization and mapping of more than 50 Mal
−
mutations located in the
malB
region lead one to divide the site for Mal
−
λs mutations (formerly called gene
malB
) in that region, into two adjacent genetic segments
malJ
and
malK. malJ
and
malK
are both involved in maltose permeation. It is suggested that (i)
malK
and
lamB
, the only known gene specifically involved in phage λ adsorption (20), constitute an operon of polarity
malK lamB
. (ii)
malJ
and
malK
correspond to two different genes, and (iii) a promoter for the
malK lamB
operon is located between
malJ
and
malK
. Since λ receptors and maltose permease are inducible by maltose and absent in
malT
mutants, it is likely that the expression of the
malK lamB
operon is controlled by the product of gene
malT
, the positive regulatory gene of the maltose system.
Mutants of
Klebsiella aerogenes
Lacking Glutamate Dehydrogenase
Authors: Brenchley Jean E. , Magasanik Boris
Published: January 2020

A mutant of
Klebsiella aerogenes
lacking glutamate synthase activity (
asm-200
) is blocked in only one pathway of glutamate synthesis and can still use glutamate dehydrogenase to produce glutamate when ammonia in sufficient concentration, i.e., higher than 1 mM, is provided in the medium. However, a mutant that has neither glutamate synthase nor glutamate dehydrogenase activities (
asm-200, gdhD1
) requires glutamate. Transductants obtained by phage grown on wild-type cells of this double mutant, selected on medium containing less than 1 mM ammonia, regain glutamate synthase but not glutamate dehydrogenase. Surprisingly, these
gdhD1
transductants grow as well in a variety of media as does a strain with glutamate dehydrogenase activity. Furthermore, transductions with these and other mutants indicate that the genes encoding glutamate synthase, glutamate dehydrogenase, glutamine synthetase, and citrate synthase are not closely linked.
Genetic Control of the 2-Keto-3-Deoxy-
d
-Gluconate Metabolism in
Escherichia coli
K-12:
kdg
Regulon
Authors: Pouyssegur Jacques , Stoeber François
Published: January 2020

2-Keto-3-deoxy-gluconate (KDG), an intermediate of the hexuronate pathway in
Escherichia coli
K-12, is utilized as the sole carbon source only in strains derepressed for the specific KDG-uptake system. KDG is metabolized to pyruvate and glyceraldehyde-3-phosphate via the inducible enzymes KDG-kinase and 2-keto-3-deoxy-6-phosphate-gluconate (KDPG) aldolase. However, another inducible pathway, where the KDG is the branch point, has been demonstrated. Genetic studies of the KDG degradative pathway reported in this paper led to the location of KDG kinase-negative and pleiotropic constitutive mutations. The
kdgK
locus, presumably the structural gene of the kinase, occurs at min 69 and is co-transducible with
xyl
. The mutants, simultaneously constitutive for the uptake, kinase, and aldolase, define a
kdgR
locus at min 36 between the co-transducible markers
kdgA
and
oldD
. As to the nature of the control exerted by the
kdgR
product, we have shown the following. (i) Thermosensitive mutants of the
kdgR
locus are inducible at low temperature but derepressed at 42 C for the three operons—
kdgT
(transport system),
kdgK
, and
kdgA
(KDPG aldolase). (ii) The
kdgR
+
allele is dominant to the
kdgR
constitutive allele. (iii) A deletion in
kdgA
extending into the regulatory gene,
kdgR
, leads to a constitutive expression of the nondeleted operons—
kdgT
and
kdgK
. These properties demonstrate that the
kdg
regulon is negatively controlled by the
kdgR
product. It is presumed that differences in operator and in promotor structures could explain the strong decoordination, respectively, in the induction and catabolic repression, of these three enzymes activities.
Growth of T-Strain Mycoplasmas in Medium Without Added Urea: Effect of Trace Amounts of Urea and of a Urease Inhibitor
Authors: Masover G. K. , Benson J. R. , Hayflick L.
Published: January 2020

Urea is currently considered to be a requirement for the propagation of T-strain mycoplasmas. We report here the replication of T-strain 960 (ATCC 25023) in media prepared from dialyzed components with added putrescine and allantoin but without added urea, or in dialyzed medium containing small amounts of added urea. The least amount of urea which allowed growth in the medium without allantoin was above 10 μg/ml. The amount of urea estimated to contaminate the added allantoin or putrescine was 5 μg/ml or less, which is insufficient to support T-strain replication. T-strain 960 was grown in the presence of urea and the urease inhibitor acetohydroxamic acid AHA where the organisms multiplied at a slower rate in the presence of AHA than in its absence. Urea hydrolysis occurred with concomitant ammonia accumulation and pH increase in cultures with AHA added.
Specificity of the Autolysin of
Streptococcus
(
Diplococcus
)
pneumoniae
Authors: Howard Lawrence V. , Gooder Harry
Published: January 2020

A
Streptococcus
(
Diplococcus
)
pneumoniae
autolysin, partially purified from cellular autolysates, was optimally active at pH 7.0 and was stimulated by monovalent cations. Addition of autolysin to walls resulted in the appearance of only N-terminal
l
-alanine, whereas no glycosidase activity was observed. Walls which had been solubilized by autolysin were separated by gel filtration into a low-molecular-weight peptide containing amino acids in the same ratios found in intact walls and a high molecular fraction containing the amino acid-deficient peptidoglycan backbone. Thus, the major activity is an
N
-acetylmuramyl-
l
-alanine amidase. In addition, walls undergoing spontaneous lysis revealed no glycosidase activity but showed an increase in only N-terminal alanine. Autolysin, which was bound to walls in saline, was almost completely removed when walls were washed in distilled water, and all of the activity was recovered in the water wash fluid.
Unusual Fibrils from the Spirochete-Like Sex Ratio Organism
Authors: Williamson David L.
Published: January 2020

Treatment of the spirochete-like Sex Ratio Organism with sodium deoxycholate results in the release of fibrils having a diameter of 3.6 nm and a period of 9 nm.
Extrachromosomal Elements in Group N Streptococci
Authors: Cords B. R. , McKay L. L. , Guerry Patricia
Published: January 2020

The deoxyribonucleic acid (DNA) of
Streptococcus lactis
C2,
S. cremoris
B
1
, and
S. diacetilactis
18-16 was labeled by growing cells in Trypticase soy broth containing
3
H-labeled thymine. The cells were gently lysed with lysozyme, ethylenediaminetetraacetic acid, and sodium lauryl sulfate. The chromosomal DNA was separated from plasmid DNA by precipitation with 1.0 M sodium chloride. The existence of covalently closed circular DNA in the three organisms was shown by cesium chloride-ethidium bromide equilibrium density gradient centrifugation of the cleared lysate material. In an attempt to correlate the loss of lactose metabolism with the loss of plasmid DNA, lactose-negative mutants of these organisms were examined for the presence of extrachromosomal particles. Covalently closed circular DNA was detected in the lactose-negative mutants of
S. lactis
C2 and
S. diacetilactis
18-16. In
S. cremoris
B
1
, however, no covalently closed circular DNA was observed by using cesium chloride-ethidium bromide gradients. Electron micrographs of the satellite band material from
S. lactis
C2 and its lactose-negative mutant confirmed the presence of plasmid DNA. Three distinct plasmids having approximate molecular weights of 1.3 × 10
6
, 2.1 × 10
6
, and 5.1 × 10
6
were observed in both organisms.
Germination of Spores of
Bacillus stearothermophilus
Induced by Analogues of Dipicolinate Di-Anion
Authors: Lewis James C. , Colman Richard
Published: January 2020

The structural specificity required for induction of germination of spores of
Bacillus stearothermophilus
by analogues of dipicolinate in buffer at pH 5.5 is similar to that found previously with spores of
Bacillus megaterium
and calcium chelate salts at pH 8. 4
H
-pyran-2,6-dicarboxylate, but no other analogue tested, is as effective as dipicolinate di-anion.
Lethal and Mutagenic Action of Black Light (325 to 400 nm) on
Haemophilus influenzae
in the Presence of Air
Authors: Cabrera-Juarez Emiliano , Espinosa-Lara Mercedes
Published: January 2020

Near-ultraviolet (UV) light (325 to 400 nm), in the presence of air and the absence of exogenous photosensitizing compounds, is lethal and mutagenic for
Haemophilus influenzae
. The lethal effect is the same for both wild type and streptomycin-resistant mutants, indicating that the mutants are not selected by the irradiation. The inactivation and mutagenicity show a large shoulder, suggesting the existence of repair systems. Filters were used to eliminate the possibility of short-UV irradiation. The effective radiation is between 325 to 400 nm. The lethal and mutagenic effects are higher during mid and late log phase than during early log or stationary phase.
Isolation of a Regulatory Mutant of Fructose-1, 6-diphosphatase in
Saccharomyces carlsbergensis
Authors: Van De Poll K. W. , Kerkenaar A. , Schamhart D. H. J.
Published: January 2020

By selecting for growth on glycerol, but absence of growth on glucose, a mutant of
Saccharomyces carlsbergensis
was isolated which does not grow on glucose, fructose, mannose, or sucrose, which shows long-term adaptation to maltose, but which can grow normally on galactose, ethanol, or glycerol. In the mutant, fructose diphosphatase is not inactivated after the addition of glucose, fructose or mannose to the medium, resulting in the simultaneous presence of fructose diphosphatase and phosphofructokinase activity. Under these conditions, a cycle is probably catalyzed between fructose-6-phosphate and fructose-1,6-diphosphate, resulting in the net consumption of adenosine triphosphate and an immediate stop of protein synthesis.
Phospholipid Metabolism and Membrane Synthesis During Sporulation in
Bacillus megaterium
Authors: Bacon Karen , White David
Published: January 2020

In view of previously published reports of localized membrane growth in exponentially growing
Bacillus megaterium
and in sporulating
Bacillus cereus
, an attempt was made to describe phospholipid metabolism and the topology of membrane synthesis during sporulation in
B. megaterium
. The cells were pulsed with radioactive glycerol or acetate at the time of septum formation, and the specific activity of the lipid fraction was measured at various times through the free spore stage. The bulk of the material labeled during septation could not be recovered in the spore. Rather, it was found that the labeled lipid fraction underwent considerable turnover during spore development. Additionally, other experiments revealed that the lipid made before the initiation of sporulation was also subject to extensive turnover. In order to minimize both the confounding effects of lipid turnover and the possible presence of lateral diffusion of labeled lipid in the membrane, autoradiography of cells pulse labeled with radioactive glycerol at the time of septation was performed; a symmetrical grain distribution resulted. Thus, despite previously published suggestions to the contrary, the current experimental techniques could not demonstrate the existence of localized membrane synthesis in
B. megaterium
during sporulation.
Bioassay for the Isolation of
Dictyostelium discoideum
Mutants Deficient in Extracellular Accumulation of Cyclic Adenosine 3′,5′-Monophosphate
Authors: Sussman Raquel R.
Published: January 2020

The growth response to external cyclic adenosine 3′,5′-monophosphate of a strain of
Escherichia coli
deleted for adenyl cyclase was utilized to screen for mutants of
Dictyostelium discoideum
unable to accumulate this chemical extracellularly. The threshold amount of cyclic adenosine 3′,5′-monophosphate able to induce growth of this bacterium was 3 to 4 μg/ml at 37 C and approximately 25 μg/ml at 27 C. Conditions are described that permit the detection of as low as 2 μg of this chemical at either temperature.
Quantal Behavior of a Diffusible Factor Which Initiates Septum Formation at Potential Division Sites in
Escherichia coli
Authors: Teather R. M. , Collins J. F. , Donachie W. D.
Published: January 2020

Analysis of nucleated cell size in a minicell-producing strain of
Escherichia coli
and in its parental strain shows that the two distributions are considerably different. A model is proposed to account for this difference. The model states that: (i) in the mutant population, the cell poles are available as potential division sites in addition to the normally located division sites; (ii) the probability of a division occurring at any of the potential division sites is equal; and (iii) only enough “division factor” arises at each unit cell doubling to permit a single division. This factor is utilized entirely in the formation of a single septum. Thus, the occurrence of a polar division with the production of an anucleate minicell (which occurs only in the mutant strain) prevents the occurrence of a non-polar division, with the result that the average nucleated cell length is increased in minicell-producing strains. The model has been used to construct a theoretical population, and a number of parameters of the real and theoretical populations have been compared. The two populations are very similar in all of the parameters measured.
Outer Membrane Proteins of
Escherichia coli
III. Evidence that the Major Protein of
Escherichia coli
O111 Outer Membrane Consists of Four Distinct Polypeptide Species
Authors: Schnaitman Carl A.
Published: January 2020

Previous studies have shown that the outer membrane of
Escherichia coli
O111 gives a single, major, 42,000-dalton protein peak when analyzed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis at neutral pH. Further studies have shown that this peak consists of more than a single polypeptide species, and on alkaline SDS-gel electrophoresis this single peak is resolved into three subcomponents designated as proteins 1, 2, and 3. By chromatography of solubilized, outer membrane protein on diethylaminoethyl-cellulose followed by chromatography on Sephadex G-200 in the presence of SDS, it was possible to separate the 42,000-dalton major protein into four distinct protein fractions. Comparison of cyanogen bromide peptides derived from these fractions indicated that they represented at least four distinct polypeptide species. Two of these proteins migrated as proteins 1 and 2 on alkaline gels. The other two proteins migrated as protein 3 on alkaline gels and cannot be separated by SDS-polyacrylamide gel electrophoresis. In purified form, these major proteins do not contain bound lipopolysaccharide, phospholipid, or phosphate. These proteins may contain a small amount of carbohydrate, as evidenced by the labeling of these proteins by glucosamine, and to a lesser extent by glucose, under conditions where the metabolism of these sugars to amino acids and lipids is blocked. All of the proteins were labeled to the same extent by these sugars. Thus, it was concluded that there are at least four distinct polypeptide species with apparent molecular masses of about 42,000 daltons in the outer membrane of
E. coli
O111.
Outer Membrane Proteins of
Escherichia coli
IV. Differences in Outer Membrane Proteins Due To Strain and Cultural Differences
Authors: Schnaitman Carl A.
Published: January 2020

When the 42,000-dalton major outer membrane protein of
Escherichia coli
O111 is examined on alkaline polyacrylamide gels containing sodium dodecyl sulfate, it is resolved into three distinct bands designated as proteins 1, 2, and 3. Band 3 consists of two distinct polypeptides, proteins 3a and 3b.
E. coli
K-12 does not make any protein 2, but makes proteins similar to 1, 3a, and 3b as indicated by comparison of cyanogen bromide peptide patterns. Several
Shigella
species and most other strains of
E. coli
resemble
E. coli
K-12 in that they lack protein 2, whereas
Salmonella typhimurium
is more similar to
E. coli
O111. In addition to these species and strain differences, cultural differences resulted in differences in the outer membrane protein profiles. Under conditions of catabolite repression, the level of protein 2 in
E. coli
O111 decreased while the level of protein 1 increased. An enterotoxin-producing strain similar to
E. coli
O111 produced no protein 1 and an elevated level of protein 2 under conditions of low catabolite repression. The levels of proteins 1 and 3 are also different in different phases of the growth curve, with protein 1 being the major species in the exponential-phase cells and protein 3 being the major species in stationary-phase cells. A multiply phage-resistant mutant of
E. coli
K-12 with no obvious cell wall defects produced no protein 1 or 2, but made increased amounts of protein 3. Thus, the major outer membrane proteins of
E. coli
and related species may vary considerably without affecting outer membrane integrity.
Lipoteichoic Acids from
Streptococcus sanguis
Authors: Chiu T. H. , Emdur L. I. , Platt D.
Published: January 2020

Two lipoteichoic acids, membrane (MLTA) and wall (WLTA), have been purified from
Streptococcus sanguis
by Sepharose and Ecteola-cellulose column chromatographies and concanavalin A-conjugated Sepharose affinity column chromatography. The teichoic acids were homogenous as judged by disc gel electrophoresis, column chromatography, and double diffusion tests. Both MLTA and WLTA consisted of glycerol, phosphate, glucose, and fatty acids in the ratios of 0.95:1:0.71:0.046 and 0.99:1:0.79:0.023, respectively. α-Glycerol-phosphate was obtained by the partial acid hydrolysis of the lipoteichoic acids suggesting that their backbone structure consists of the glycerol moieties linked by 1, 3-phosphodiester bonds. Both WLTA and MLTA form aggregates, perhaps due to micelle formation, in concentrated solution. The aggregate form of MLTA dissociates to a much greater extent than that of WLTA under similar conditions.
Ribonucleic Acid Polymerases of the Yeast Phase of
Histoplasma capsulatum
Authors: Boguslawski George , Schlessinger David , Medoff Gerald , Kobayashi George
Published: January 2020

Ribonucleic acid (RNA) polymerases of
Histoplasma capsulatum
(yeast phase) were fractionated by phosphocellulose chromatography and partially characterized. Three distinct, active fractions were seen. The major RNA polymerase species was inhibited strongly by α-amanitin, whereas the other two were resistant. When either slightly purified (HSE) extract or the major active component was assayed at 37 C, the incorporation of tritiated uridine monophosphate into RNA stopped after 10 to 15 min. In contrast, the synthesis continued for at least 1 h at 23 C. The other two RNA polymerase species exhibited higher rates of incorporation when tested at 37 C, and continued to synthesize RNA even after 60 min. However, by that time the levels of incorporation at 23 C were higher than at 37 C for all three enzymes. The temperature sensitivity was not affected by changing substrate concentration or employing either native or denatured calf thymus deoxyribonucleic acid as a template. These results are compared with the data obtained with RNA polymerases from different fungi and other organisms. A possible involvement of RNA polymerase(s) in morphological differentiation of
H. capsulatum
is discussed.
Inhibition of Transformation by Sodium Metaperiodate in
Streptococcus sanguis
(Wicky): Demonstration That Deoxyribonucleic Acid Binding Sites Contain Amino Acids
Authors: Ranhand Jon M.
Published: January 2020

Addition of sodium metaperiodate to competent
Streptococcus sanguis
(Wicky) cells at 0 or 37 C revealed that the deoxyribonucleic acid binding sites consist of amino acids.
Direct Selection for P1-Sensitive Mutants of Enteric Bacteria
Authors: Goldberg Richard B. , Bender Robert A. , Streicher Stanley L.
Published: January 2020

A method has been developed to isolate mutants sensitive to coliphage P1 from bacterial genera normally not sensitive to this phage. P1clr100KM was used. This phage is heat inducible and confers kanamycin resistance when present as a prophage (in lysogens). P1-sensitive mutants of
Klebsiella, Enterobacter, Citrobacter
, and
Erwinia
have been found. This technique provides a well-known genetic system for the study of many bacterial genera that previously had either no such system or only a marginally useful means of genetic manipulation. It also extends the range of possible intergeneric hybrids that may be constructed and studied.
Distribution of the Isopropylmalate Pathway to Leucine Among Diverse Bacteria
Authors: Stieglitz B. I. , Calvo J. M.
Published: January 2020

α-Isopropylmalate synthase and β-isopropylmalate dehydrogenase activities were detected in extracts of the following organisms:
Chromatium
D,
Rhodopseudomonas spheroides, Hydrogenomonas
H16,
Pseudomonas aeruginosa, Pseudomonas fluorescens, Vibrio extorquens, Rhizobium japonicum, Alcaligenes viscolactis, Escherichia coli
B,
Proteus vulgaris, Aerobacter aerogenes, Salmonella typhimurium, Micrococcus
sp.,
Micrococcus lysodeikticus, Bacillus polymyxa, Bacillus subtilis
, and
Nocardia opaca
. The α-isopropylmalate synthase activity in these extracts was inhibited by low concentrations of
l
-leucine. Taken together with other data, these results suggest that the isopropylmalate pathway is widespread among organisms that can synthesize leucine.
Threonine Locus of
Escherichia coli
K-12: Genetic Structure and Evidence for an Operon
Authors: Thèze J. , Saint-Girons I.
Published: January 2020

Three genes,
thrA, thrB
, and
thrC
, were previously defined and localized in the threonine locus of
Escherichia coli
K-12.
thrA, thrB
, and
thrC
specify the enzymes aspartokinase I-homoserine dehydrogenase I, homoserine kinase, and threonine synthetase, respectively. A complementation analysis of the threonine cluster using derivatives of a lambda phage carrying the threonine genes (λ
dthr
c
) demonstrates that: (i)
thrB
and
thrC
each consist of a single cistron; and (ii)
thrA
is composed of two cistrons,
thrA
1
and
thrA
2
, although it specifies a single polypeptide chain.
thrA
1
and
thrA
2
correspond to aspartokinase I and homoserine dehydrogenase I, respectively. Their relative order is established. The demonstration of polar effects of mutations (nonsense or induced by phage Mu) in
thrA
and
thrB
is taken as evidence for the existence of a
thrA thrB thrC
operon, transcribed in this order.
Cell-Free Mercury(II)-Reducing Activity in a Plasmid-Bearing Strain of
Escherichia coli
Authors: Summers Anne O. , Sugarman Laurence I.
Published: January 2020

The ability to reduce Hg(II) to Hg(0), which is determined by a plasmid-borne gene in
Escherichia coli
, is conferred by a Hg(II)-inducible activity which is located in the cytoplasm rather than in the periplasmic space of the cell. This Hg(II)-reducing activity can be isolated from the supernatant of a 160,000 ×
g
centrifugation after French Press disruption of the cells. The activity is dependent on glucose-6-phosphate, glucose-6-phosphate dehydrogenase, and 2-mercaptoethanol, but is not enhanced by added nicotinamide adenine dinucleotide phosphate. Treatment of the active fraction with
N
-ethylmaleimide causes irreversible loss of the Hg(II)-reducing activity. Unlike the Hg(II)-reducing activity found in intact cells, the cell-free activity is not inhibited by toluene, potassium cyanide, or
m
-chlorocarbonylcyanide-phenylhydrazone; however, it is inhibited by Ag(I) and phenylmercuric acetate to the same extent as the activity in intact cells. Neither phenylmercuric acetate nor methylmercuric chloride is reduced to Hg(0) by the cell-free activity. Au(III), however, is a substrate for the cell-free activity; it is reduced to metallic colloidal Au(0).
Morphology of Bacteriophage-Like Particles from
Fusobacterium symbiosum
Authors: Foglesong M. A. , Markovetz A. J.
Published: January 2020

The morphology of bacteriophage-like particles from the strict anaerobe
Fusobacterium symbiosum
is described. Attempts to demonstrate plaque formation on the host strain of
F. symbiosum
and other related species were unsuccessful.
l
-Arabinose Metabolism in
Rhizobium japonicum
Authors: Pedrosa Fábio O. , Zancan Glaci T.
Published: January 2020

l
-Arabinose was metabolized through an oxidative pathway by extracts of a strain of
Rhizobium japonicum
. The findings showed that
l
-arabinose is converted into 2-keto-3-deoxy-
l
-arabonate, which is cleaved into glycoaldehyde and pyruvate.
Metabolic Consequences of a Block in the Synthesis of 5-Keto-
d
-Fructose in a Mutant of
Gluconobacter cerinus
Authors: Mowshowitz Solomon , Englard Sasha , Avigad Gad
Published: January 2020

A mutant of
Gluconobacter cerinus
var.
ammoniacus
, IFO 3267, has been isolated which is deficient with respect to fructose 5-dehydrogenase, the enzyme catalyzing the oxidation of
d
-fructose to 5-keto-
d
-fructose (5 KF). Growth of this mutant on fructose as the sole carbon source was impaired unless the culture medium was supplemented with 5 KF. Significant randomization of the 1 and 6 positions of fructose has been reported previously for the wild-type organism during growth on this ketohexose. The pattern of
3
H incorporation into the C5 position of ribonucleic acid-ribose when the mutant was grown on [1-
3
H]fructose and [6-
3
H]fructose in the presence of 5 KF indicated that such randomization did not occur in this variant. The randomization observed in the wild type is, therefore, a consequence of the partial oxidation of fructose to the symmetrical 5 KF intermediate prior to its conversion to pentose. When the mutant was grown on [1-
3
H]fructose in the presence of unlabeled 5 KF, [5-
3
H]fructose appeared in the culture medium. Thus, 5 KF served as the oxidant for the nicotinamide adenine dinucleotide phosphate, reduced form, generated during growth on fructose.
Mutant of
Salmonella typhimurium
That Channels Infecting Bacteriophage P22 Toward Lysogenization
Authors: Tokuno Shin-Ichi , Goldschmidt Eugene P. , Gough Michael
Published: January 2020

A slowly growing, polymyxin-sensitive mutant of
Salmonella typhimurium
was isolated. Wild-type phage P22 form plaques on the mutant at 5 × 10
−4
, the frequency observed on wild-type hosts. All P22 clear mutants form plaques with near normal frequency. The inability of the mutant to form plaques is correlated with an increase in lysogenization frequency. The cause of the increased lysogenization frequency is not known, but it is not the result of overproduction of cyclic adenosine 5′-monophosphate.
Derepression of Synthesis of the Aminoacyl-Transfer Ribonucleic Acid Synthetases for the Branched-Chain Amino Acids of
Escherichia coli
Authors: McGinnis Etheleen , Williams Ann C. , Williams L. S.
Published: January 2020

The kinetics of derepression of valyl-, isoleucyl-, and leucyl-transfer ribonucleic acid (tRNA) synthetase formation was examined during valine-, isoleucine-, and leucine-limited growth. When valine was limiting growth, valyl-tRNA synthetase formation was maximally derepressed within 5 min, whereas the rates of synthesis of isoleucyl-, and leucyl-tRNA synthetases were unchanged. Isoleucine-restricted growth caused a maximal derepression of isoleucyl-tRNA synthetase formation in 5 min and derepression of valyl-tRNA synthetase formation in 15 min with no effect on leucyl-tRNA synthetase formation. When leucine was limiting growth, leucyl-tRNA synthetase formation was immediately derepressed, whereas valyl- and isoleucyl-tRNA synthetase formation was unaffected by manipulation of the leucine supply to the cells. These results support our previous findings that valyl-tRNA synthetase formation is subject to multivalent repression control by both isoleucine and valine. In contrast, repression control of iso-leucyl- and leucyl-tRNA synthetase formation is specifically mediated by the supply of the cognate amino acid.