bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Ribosomes from Viomycin-Sensitive and -Resistant Strains of
Mycobacterium smegmatis
Authors: Yamada Takeshi , Masuda Kunitsugu , Shoji Ko , Hori Mitsuo
Published: January 2020

Viomycin-resistant strains were isolated from
Mycobacterium smegmatis
. Ribosomes were isolated and tested for drug resistance in subcellular systems containing poly(U) as messenger ribonucleic acid. Resistance to viomycin in these strains was due to altered ribosomes. Further analysis showed that viomycin resistance of two mutants with low level resistance (20 μg/ml) was due to altered 30
S
ribosomal subunits. Another mutant that was highly resistant to viomycin (1 mg/ml), however, had altered 50
S
ribosomal subunits.
Production and Purification of a
Staphylococcus epidermidis
Bacteriocin
Authors: Jetten A. M. , Vogels G. D. , de Windt F.
Published: January 2020

Liquid cultures of
Staphylococcus epidermidis
1580 contained rather small amounts of a bacteriocin, staphylococcin 1580, which was found both in the supernatant fluid and in the cell pellet. It could be extracted from the cells with 5% NaCl solution. The staphylococcin production could not be induced by ultraviolet irradiation or treatment with mitomycin C. Bacteria grown on semisolid medium produced a much larger amount of the compound with a high specific activity. The staphylococcin was purified by ammonium sulfate precipitation, ultracentrifugation, and chromatography on Sephadex columns. The purified material was homogeneous on polyacrylamide gel electrophoresis. The molecular weight was between 150,000 and 400,000. The bacteriocin was composed of protein, carbohydrate, and lipid and consisted of subunits exhibiting a molecular weight of about 20,000.
Nature and Properties of aStaphylococcus epidermidisBacteriocin
Authors: Jetten A. M. , Vogels G. D.
Published: January 2020

Staphylococcin 1580, produced byStaphylococcus epidermidis1580, consisted of 41.8% protein, 34% carbohydrate, and 21.9% lipid. In the protein fraction, the acidic amino acids, glutamic and aspartic acid, and the neutral amino acids, glycine and alanine, predominated. Neutral sugars consisted of glucose, galactose, and fucose in a molar ratio of 6:3:1. The purified bacteriocin was not inactivated by heating for 15 min at 120 C in the presence of 0.5% serum albumin and was stable in thepH range from 3.5 to 8.5. The compound was sensitive to the action of the proteolytic enzymes trypsin, Pronase, and chymotrypsin. All gram-negative bacteria tested were resistant; a large number of gram-positive bacteria were sensitive to staphylococcin 1580 action. Growth of stable staphylococcal L-forms was inhibited by the bacteriocin to the same extent as their parent strains. The staphylococcin was adsorbed to cell walls, cell membranes, and resistant cells. The effect of staphylococcin 1580 appeared to be bactericidal but not bacteriolytic.
Regulation of Macromolecular Synthesis by Putrescine in a Conditional
Escherichia coli
Putrescine Auxotroph
Authors: Young Delano V. , Srinivasan P. R.
Published: January 2020

Addition of putrescine to a slowly growing, polyamine-starved
Escherichia coli
K-12 mutant conditionally incapable of synthesizing putrescine causes the immediate stimulation of protein synthesis. After a period ranging from 60 to 105 min, ribonucleic acid (RNA) and deoxyribonucleic acid (DNA) syntheses are also stimulated and rapid cellular division begins. Chloramphenicol blocks this rapid cellular division, although addition of the specific DNA synthesis inhibitor, nalidixic acid, has no effect on cell division. By sucrose gradient analysis and diethylaminoethyl-cellulose chromatography, the proteins initially made in response to putrescine appear to be composed of many classes, including membrane-bound proteins. However, the synthesis of ribosomal subunits is not altered during this period. A possible role for putrescine in either the stimulation of messenger RNA transcription or in translation is suggested.
Chemotaxis Toward Amino Acids in
Escherichia coli
Authors: Mesibov Robert , Adler Julius
Published: January 2020

Escherichia coli
cells are shown to be attracted to the
l
-amino acids alanine, asparagine, aspartate, cysteine, glutamate, glycine, methionine, serine, and threonine, but not to arginine, cystine, glutamine, histidine, isoleucine, leucine, lysine, phenylalanine, tryptophan, tyrosine, or valine. Bacteria grown in a proline-containing medium were, in addition, attracted to proline. Chemotaxis toward amino acids is shown to be mediated by at least two detection systems, the aspartate and serine chemoreceptors. The aspartate chemoreceptor was nonfunctional in the aspartate taxis mutant, which showed virtually no chemotaxis toward aspartate, glutamate, or methionine, and reduced taxis toward alanine, asparagine, cysteine, glycine, and serine. The serine chemoreceptor was nonfunctional in the serine taxis mutant, which was defective in taxis toward alanine, asparagine, cysteine, glycine, and serine, and which showed no chemotaxis toward threonine. Additional data concerning the specificities of the amino acid chemoreceptors with regard to amino acid analogues are also presented. Finally, two essentially nonoxidizable amino acid analogues, α-aminoisobutyrate and α-methylaspartate, are shown to be attractants for
E. coli
, demonstrating that extensive metabolism of attractants is not required for amino acid taxis.
Oxidation of Nicotinic Acid by a
Bacillus
Species: Regulation of Nicotinic Acid and 6-Hydroxynicotinic Acid Hydroxylases
Authors: Hirschberg Rona , Ensign J. C.
Published: January 2020

The first two enzymes employed by a
Bacillus
species for the dissimilation of nicotinic acid are coordinately induced. The inducer of the enzymes appears to be 6-hydroxynicotinic acid, the product of the first enzyme in the pathways. Synthesis of the enzymes is repressed by glucose when ammonium is present in the medium, but not when nicotinic acid is the sole nitrogen source. The possible significance of the coordinate induction and unusual repression is discussed.
Effects of Phosphonic Acid Analogues of Glycerol-3-Phosphate on the Growth of
Escherichia coli
Authors: Shopsis Charles S. , Engel Robert , Tropp Burton E.
Published: January 2020

The four-carbon phosphonate, 3,4-dihydroxybutyl-1-phosphonate, is similar to glycerol-3-phosphate in its ability to inhibit cell growth of
Escherichia coli
strain 8 cultured in low-phosphate synthetic medium supplemented with either succinate or casein hydrolysate as the sole carbon source. The three-carbon phosphonate, 2,3-dihydroxypropyl-1-phosphonate, does not appear to exhibit a similar effect. The inhibition caused by the four-carbon phosphonate differs from that caused by glycerol-3-phosphate in at least three ways. (i) Its inhibitory effect is not offset by the presence of glucose in the culture medium. (ii) It is capable of exerting its inhibitory effect on cells containing an active aerobic glycerol-3-phosphate dehydrogenase. (iii) Its inhibitory effect is maintained in synthetic medium containing high concentrations of inorganic phosphate. The four-carbon phosphonate appears to be bacteriostatic and inhibits the uptake of labeled glycerol-3-phosphate by
E. coli
strain 8.
Adenine Phosphoribosyltransferase in
Mycoplasma mycoides
and
Escherichia coli
Authors: Sin Iris L. , Finch L. R.
Published: January 2020

Some kinetic properties of the adenine phosphoribosyltransferases from
Escherichia coli
and
Mycoplasma mycoides
have been studied. For the
E. coli
enzyme, Michaelis constants for adenine and 5-phosphoribosyl-1-pyrophosphate (PRPP) are 1.3 and 10 μ
m
, respectively. Adenosine monophosphate, the most effective nucleotide inhibitor, inhibits competitively with respect to PRPP, the inhibition constant being 26 μ
m
. The
M. mycoides
enzyme has more complex kinetics. The response to increasing PRPP concentration is sigmoidal, the degree of sigmoidality depending on both the concentration of adenine and the
p
H. At low PRPP levels, high concentrations of adenine are inhibitory. Guanosine monophosphate is the most effective inhibitor, being inhibitory at all
p
H values, but other nucleotides have been found to activate at
p
H 7 and inhibit at
p
H 8. The elution profile of the
M. mycoides
enzyme from Sephadex suggests an association of enzyme subunits in the presence of PRPP. This is consistent with the observed kinetics if the associated form has increased stability and activity.
Mapping of
rfa
Genes in
Salmonella typhimurium
by ES18 and P22 Transduction and by Conjugation
Authors: Kuo Tseng-Tong , Stocker B. A. D.
Published: January 2020

Loci termed
rfa
, determining biosynthesis of somatic lipopolysaccharide core, have been mapped in
Salmonella typhimurium
LT2. The smooth-specific phage P22 co-transduced two leaky
rfa
alleles with
cysE
and with
pyrE
; one of the leaky alleles is perhaps
rfaG
, and the other is an unidentified gene concerned with synthesis of the heptose-containing part of the core. The lipopolysaccharide-indifferent phage ES18 (or its variant ES18.
h1
) co-transduced
rfaF, rfaG, rfaL, rfa
(R-res-1), and
rfa
(R-res-2) alleles with
cysE
and with
pyrE
, at rates indicating the order
cysE–rfaF
–(
rfa
[R-res-1],
rfa
[
r-res-2
],
rfaL
)–
rfaG–pyrE
. One proven (and two suspected)
rfaE
alleles and five proven
rfaH
alleles were not co-transduced with
cysE
or
pyrE
. Hfr crosses indicated that the proven
rfaE
allele mapped between
serA
and
strA
.
Effect of
p
H on Adenine and Amino Acid Uptake During Sporulation in
Saccharomyces cerevisiae
Authors: Mills Dallice
Published: January 2020

During the early stages of sporulation in
Saccharomyces cerevisiae
, the
p
H of the acetate sporulation medium rises to values of 8.0 or higher. Associated with this rise in
p
H is a reduced cell permeability to certain precursors of ribonucleic acid (RNA), deoxyribonucleic acid or protein. Uptake of adenine, alanine, and leucine was optimal at
p
H 5.6 to 6.0, but sporulation was inhibited when the sporulation medium was buffered below
p
H 7.0. Cellular impermeability can be largely overcome by adjusting the acetate sporulation medium to
p
H 6.0 for optimal uptake of
14
C-adenine during short pulses without any apparent effect on sporulation. Sporulating cells pulse-labeled 20 min at
p
H 6.0 incorporated 40 times more
14
C-adenine into RNA than sporulating cells pulse-labeled at
p
H 8.0. This increased incorporation can be attributed to a 100-fold increase in labeled adenosine triphosphate in cells pulse-labeled at
p
H 6.0 where maximum uptake occurs.
Effect of Pyrrolnitrin on Electron Transport and Oxidative Phosphorylation in Mitochondria Isolated from
Neurospora crassa
Authors: Lambowitz Alan M. , Slayman Carolyn W.
Published: January 2020

Pyrrolnitrin, at low concentrations, uncouples oxidative phosphorylation in
Neurospora
mitochondria. At higher concentrations, pyrrolnitrin inhibits electron transport both in the flavine region and through cytochrome oxidase.
5-Bromouracil-Tolerant Mutants of
Bacillus subtilis
Authors: Bishop Robert J. , Sueoka Noboru
Published: January 2020

5-Bromouracil (BU)-tolerant mutants of
Bacillus subtilis
23 (
thy his
) have been isolated. Several classes of tolerant mutants were obtained by a sequential selection procedure. The classes can be distinguished by their relative BU tolerance as well as several other phenotypic characteristics. The mutants can grow for an extended period of time in minimal medium supplemented with amino acids and BU, in which the sensitive parental strain (Bu
+
) undergoes rapid cell death. Both mutants But-1 and But-1310 have a greater rate of deoxyribonucleic acid (DNA) synthesis by a factor of two in the presence of BU than Bu
+
, But-1 being somewhat faster than But-1310. The preferential incorporation of thymine to BU of But-1 is about half that of the Bu
+
strain during DNA replication in minimal medium supplemented with 10 μg of BU/ml and 1 μg of thymine/ml. It is not known at what step or steps this reduction in selectivity occurs.
Restoration of Phosphoribosyl Transferase Activity by Partially Deleting the
trpB
Gene in the Tryptophan Operon of
Salmonella typhimurium
Authors: La Scolea Leonard J. , Balbinder Elias
Published: January 2020

The amber mutant
trpA28
, which contains a mutation mapping within the so-called “unusual” region of the tryptophan (
trp
) operon of
Salmonella typhimurium
(between the genes
trpA
and
trpB
), lacks both components of the anthranilate synthetase (AS)-phosphoribosyl transferase (PRT) enzyme complex, the products of the genes
trpA
and
trpB
, respectively. Twenty-six revertants of this mutant selected on minimal medium supplemented with anthranilic acid, a substrate of PRT, contain deletions of various segments of the “unusual” region and make a species of PRT different in every respect from the wild-type, dissociated form of this enzyme. The results indicate that the unusual region corresponds to the operator proximal end of the
trpB
gene. Mutants in the unusual region, however, show unexpectedly low levels of AS activity and in two cases (
trpA515
and
trpA28
) no detectable activity of this enzyme component.
Genetic Analysis of Phenylalanine-Responding Mutants of
Pseudomonas aeruginosa
Authors: Waltho Judith A.
Published: January 2020

A transduction analysis of phenylalanine-responding mutants of
Pseudomonas aeruginosa
revealed the existence of six unlinked genes. Enzyme assays showed that one gene was involved in the terminal production of phenylalanine (chorismate mutase), and the remaining five genes were involved in the common pathway of aromatic amino acid biosynthesis.
Enterochelin System of Iron Transport in
Escherichia coli:
Mutations Affecting Ferric-Enterochelin Esterase
Authors: Langman Lyndall , Young I. G. , Frost G. E. , Rosenberg H. , Gibson F.
Published: January 2020

Three mutant strains of
Escherichia coli
have been isolated which are lacking ferric-enterochelin esterase activity. This enzyme catalyzes the hydrolysis of the enterochelin moiety of ferric-enterochelin to yield ultimately three molecules of
N
-2,3-dihydroxybenzoylserine. The mutants (designated
fes
−
) were shown to be unaffected in enterochelin biosynthesis, capable of enterochelin-mediated iron uptake, and able to utilize ferric-dihydroxybenzoylserine complexes normally. When grown under iron-deficient conditions, however, they showed an absolute requirement for added iron or citrate, a phenotype characteristic of mutants defective in some part of the enterochelin system of iron uptake. These results support the theory that iron, taken up by the cell as ferric-enterochelin is only available for general cell metabolism after hydrolysis of the ligand by enterochelin esterase. The three
fes
−
strains were shown to be affected in the B component of enterochelin esterase. The
fesB
gene which is probably the structural gene coding for component B of the esterase, was shown to be located at about minute 14 on the
E. coli
chromosome together with seven other genes involved in the enterochelin system of iron transport.
Polyamine Metabolism in Potassium-Deficient Bacteria
Authors: Rubenstein Kenneth E. , Streibel Ellen , Massey Sarah , Lapi Lillie , Cohen Seymour S.
Published: January 2020

The metabolism of polyamines was studied in K
+
-dependent strains of
Escherichia coli
. When these stringent organisms were in a medium containing Na
+
instead of K
+
, protein synthesis was arrested, but synthesis of ribonucleic acid continued as it would in a relaxed organism. The Na
+
medium inhibited synthesis of spermidine and
S
-adenosylmethionine. However, the synthesis of putrescine was accelerated at least five- to eightfold. Exogenous ornithine doubled even this rate of putrescine synthesis but did not increase the low level of putrescine synthesis in the K
+
medium. In K
+
or Na
+
media, with or without 0.3 m
m
arginine, putrescine was derived almost entirely from ornithine via ornithine decarboxylase. Addition of spermidine (5 m
m
) to a Na
+
culture markedly inhibited putrescine synthesis. The ornithine decarboxylase of an extract of a K
−
-dependent strain prepared at low ionic strength was separated from ribosomes, deoxyribonucleic acid, and associated polyamines by centrifugation, and from many ions by ultrafiltration and fractionation on Sephadex G-100. Addition of Na
+
and K
+
salts to 200 m
m
was markedly inhibitory. The combined reductions both in synthesis of the inhibitor spermidine and in intracellular ionic strength may explain the in vivo activation of this enzyme.
Nonfunctional Tricarboxylic Acid Cycle and the Mechanism of Glutamate Biosynthesis in
Acetobacter suboxydans
Authors: Greenfield Seymour , Claus G. W.
Published: January 2020

Acetobacter suboxydans
does not contain an active tricarboxylic acid cycle, yet two pathways have been suggested for glutamate synthesis from acetate catalyzed by cell extracts: a partial tricarboxylic acid cycle following an initial condensation of oxalacetate and acetyl coenzyme A. and the citramalate-mesaconate pathway following an initial condensation of pyruvate and acetyl coenzyme A. To determine which pathway functions in growing cells, acetate-
1
-
14
C
was added to a culture growing in minimal medium. After growth had ceased, cells were recovered and fractionated. Radioactive glutamate was isolated from the cellular protein fraction, and the position of the radioactive label was determined. Decarboxylation of the C5 carbon removed 100% of the radioactivity found in the purified glutamate fraction. These experiments establish that growing cells synthesize glutamate via a partial tricarboxylic acid cycle. Aspartate isolated from these hydrolysates was not radioactive, thus providing further evidence for the lack of a complete tricarboxylic acid cycle. When cell extracts were analyzed, activity of all tricarboxylic acid cycle enzymes, except succinate dehydrogenase, was demonstrated.
Evidence for Vectorial Phosphorylation of
d
-Fructose by Intact Cells of
Aerobacter aerogenes
Authors: Kelker Norman E. , Anderson Richard L.
Published: January 2020

Extracellular
d
-fructose was metabolized preferentially over intracellular
d
-fructose in growing cells of a
d
-fructokinaseless mutant of
Aerobacter aerogenes
. This finding is interpreted to indicate that phosphorylation of
d
-fructose by the membrane-bound phosphoenolpyruvate:
d
-fructose 1-phosphotransferase system in intact cells is coupled to unidirectional transport.
Effect of Thymine Starvation on Deoxyribonucleic Acid Repair Systems of
Escherichia coli
K-12
Authors: Anderson Janet A. , Barbour Stephen D.
Published: January 2020

Thymine starvation of
Escherichia coli
K-12 results in greatly increased sensitivity to ultraviolet light (UV). Our studies, using isogenic strains carrying
rec
and
uvr
mutations, have shown the following. (i) Common to all strains tested is a change from multihit to single-hit kinetics of survival to UV after 60 min of thymine starvation. However, the limiting slope of UV survival curves decreases in the
rec
+
uvr
+
strain and changes very little in several
rec
mutant strains and one
uvrB
mutant strain. Thus, when either the
rec
or
uvr
system is functioning alone, the limiting slopes of the UV survival curves are relatively unaffected by thymine starvation. (ii) Thymine starvation does not significantly inhibit repair processes carried out by either repair system alone; i.e., host cell reactivation of irradiated phage (carried out by the
uvr
system), excision of thymine dimers (
uvr
), or X-ray repair (
rec
). (iii) In a
rec
+
uvr
+
strain, repair appears to be a synergistic rather than additive function of the two systems. However, after thymine starvation, repair capacity is reduced to about the sum of the repair capacities of the independent systems. (iv) The kinetics of thymineless death are not changed by
rec
and
uvr
mutations. This indicates that the lesions responsible for thymineless death are not repaired by
rec
or
uvr
systems. (v) Withholding thymine from
thy rec
+
uvr
+
bacteria not undergoing thymineless death has no effect on UV sensitivity. Under these conditions one sees higher than normal UV resistance in the presence or absence of thymine. This is due to increased repair carried out by the
uvr
system. To explain these results we postulate that thymine starvation does not inhibit either the
rec
or
uvr
repair pathway directly. Rather it appears that thymine starvation results in increased UV sensitivity in part by inhibiting a function which normally carries out efficient coordination of
rec
and
uvr
pathways.
Ecology of
Vibrio parahaemolyticus
in Chesapeake Bay
Authors: Kaneko Tatsuo , Colwell Rita R.
Published: January 2020

A study of the ecology of
Vibrio parahaemolyticus
and related vibrios in the Rhode River area of Chesapeake Bay was carried out over the period December 1970 through August 1971. The incidence of
V. parahaemolyticus
and related vibrios was found to be correlated with water temperature. The vibrios could not be detected in the water column during the winter months, although they were present in sediment. From late spring to early summer, when water temperatures were 14 ± 1 C, vibrios over-wintering in sediment were released from the bottom communities and attached to zooplankton, proliferating as the temperature rose. The number of vibrios in and on plankton was reflected in the water column bacterial population densities at water temperatures of ca. 19 C. Thus, temperature of the water column in the range of 14 to 19 C was found to be critical in the annual cycle of the vibrios. Interaction between sediment, water, and zooplankton was found to be essential in the natural estuarine ecosystem. Bacterial counts of zooplankton were found to be temperature dependent. The bacterial population associated with zooplankton was found to be predominantly on external surfaces and was specific, differing from that of the sediment.
Vibrio
spp. and related organisms comprised the total bacterial population associated with zooplankton in summer months. The ecological role of
Vibrio
spp., including
V. parahaemolyticus
, was found to be significant, with respect to their property of chitin digestion and in relation to the population dynamics of zooplankton in Chesapeake Bay.
Aryl Sulfatase in Ascospores of
Neurospora crassa
Authors: Burton Earl G. , Metzenberg Robert L.
Published: January 2020

Neurospora crassa
ascospores normally do not contain aryl sulfatase even when formed under conditions of sulfur limitation. However, when one of the parental strains is the nonrepressible mutant

scon
c

, the resulting (mixed) ascospores contain significant levels of aryl sulfatase even when formed under conditions of sulfur abundance.
Inorganic Phosphate Transport in
Escherichia coli
: Involvement of Two Genes Which Play a Role in Alkaline Phosphatase Regulation
Authors: Willsky Gail R. , Bennett Robert L. , Malamy Michael H.
Published: January 2020

Two classes of alkaline phosphatase constitutive mutations which comprise the original
phoS
locus (genes
phoS
and
phoT
) on the
Escherichia coli
genome have been implicated in the regulation of alkaline phosphatase synthesis. When these mutations were introduced into a strain dependent on a single system, the
pst
system, for inorganic phosphate (P
i
) transport, profound changes in P
i
transport were observed. The
phoT
mutations led to a complete P
i
−
phenotype in this background, and no activity of the
pst
system could be detected. The introduction of the
phoS
mutations changed the specificity of the
pst
system so that arsenate became growth inhibitory. Changes in the phosphate source led to changes in the levels of constitutive alkaline phosphatase synthesis found in
phoS
and
phoT
mutants. When glucose-6-phosphate or
l
-α-glycerophosphate was supplied as the sole source of phosphate,
phoT
mutants showed a 3- to 15- fold reduction in constitutive alkaline phosphatase synthesis when compared to the maximal levels found in limiting P
i
media. However, these levels were still 100 times greater than the basal level of alkaline phosphatase synthesized in wild-type strains under these conditions. The
phoS
mutants showed only a two- to threefold reduction when grown with organic phosphate sources. The properties of the
phoT
mutants selected on the basis of constitutive alkaline phosphatase synthesis were similar in many respects to those of
pst
mutants selected for resistance to growth inhibition caused by arsenate. It is suggested that the
phoS
and
phoT
genes are primarily involved in P
i
transport and, as a result of this function, play a role in the regulation of alkaline phosphatase synthesis.
Membrane Lipids of
Mycoplasma hominis
Authors: Rottem Shlomo , Razin Shmuel
Published: January 2020

Essentially all of the lipids of
Mycoplasma hominis
(200 μg/mg of cell protein) were found to be located in the cell membrane. Over one-half were neutral lipids incorporated from the growth medium and consisting of 43% free cholesterol, 19% esterified cholesterol, 23% triglycerides, 10% free fatty acids, and small amounts of di- and monoglycerides. The polar lipids accounting for about 40% of the total were synthesized by the organisms. Phosphatidylglycerol was the predominant lipid of this fraction. The minor components, tentatively identified as lysophosphatidylglycerol and phosphatidic acid, seem to represent breakdown products of phosphatidylglycerol. No glycolipids were detected. Being unable to synthesize long-chain fatty acids,
M. hominis
utilized the fatty acids of the growth medium for polar lipid synthesis, preferentially the saturated ones, so that the polar lipids had highly saturated hydrocarbon chains. It is proposed that the large take up of unsaturated neutral lipids and cholesterol from the medium offsets the marked condensing effect of the saturated polar lipids, although electron paramagnetic resonance spectrometry of spin-labeled fatty acids incorporated into the
M. hominis
membrane indicated that the lipid region is still more rigid than that of the
Acholeplasma laidlawii
membrane.
Structure of Cell Wall Lipopolysaccharide from
Salmonella typhimurium
IV. Anomeric Configuration of
l
-Rhamnose Residues and Its Taxonomic Implications
Authors: Kita Hiroshi , Nikaido Hiroshi
Published: January 2020

A major portion of cell wall lipopolysaccharide from group A, group B, or group D
1
Salmonella
corresponds to a linear polysaccharide chain, which consists of α-
d
-galactosyl-(1 → 2)-α-
d
-mannosyl-(1 → 4)-
l
-rhamnosyl-(1 → 3)-repeating units, and has short branches of single 3,6-dideoxyhexose residues. The groups differ in the configuration of the 3,6-dideoxyhexose present. Furthermore, it has been claimed that the anomeric configuration of the rhamnosyl residues is β-
l
in group B, in contrast to the α-
l
configuration found in groups A and D
1
. In this study, oligosaccharides containing more than one repeating unit were isolated from a lipopolysaccharide of a group B
Salmonella
, and the anomeric configuration of the rhamnosyl residues was determined by the comparison of optical rotatory powers of these oligosaccharides with that of the repeating unit trisaccharide. The results established the configuration of rhamnose as α-
l
, in contrast to the β-
l
configuration suggested in the literature. Since rhamnosyl linkages in lipopolysaccharide of a group D
1
Salmonella
are hydrolyzed in acid at exactly the same rate as are those in group B
Salmonella
, the configuration of rhamnose residues in groups D
1
lipopolysaccharide is also likely to be α-
l
. These results indicate that lipopolysaccharides of
Salmonella
groups A, B, and D
1
share an identical main chain polysaccharide and differ essentially only in the configuration of 3,6-dideoxyhexose branches; they thus suggest close evolutionary relationship between these three serogroups of
Salmonella
.
Protein Synthesis and Deoxyribonucleic Acid-Membrane Attachment During Thymineless Death in
Escherichia coli
Authors: Dankberg Frances , Cummings Donald J.
Published: January 2020

The proteins synthesized during thymineless death in
Escherichia coli
B and B/r were analyzed by polyacrylamide gel elctrophoresis. It was found that the amount of a protein of molecular weight 80,000 to 88,000 is greatly increased during thymineless death compared to the amounts of other cell proteins. A technique for the isolation of cell membrane-deoxyribonucleic acid (DNA)-nascent ribonucleic acid (RNA) complex on detergent crystals was used to determine whether DNA might be detached from the cell membrane as a result of thymineless death. It was found that under no conditions of thymineless death or immunity to thymineless death was there any change in the attachment of DNA or pulse-labeled RNA to cell membrane.
Isolation and Characterization of the Fertility Factor P of
Vibrio cholerae
Authors: Datta Archana , Parker Charlotte D. , Wohlhieter J. A. , Baron L. S.
Published: January 2020

Vibrio cholerae
strains with the transmissible fertility factor P contained a supercoiled circular deoxyribonucleic acid (DNA) component amounting to between 2 and 6% of the total DNA obtained from the cells. Such a component was not observed in
V. cholerae
strains lacking the fertility factor. This supercoiled circular DNA was isolated from P
+
cells, and the molecular weight was determined by sedimentation velocity experiments and electron microscopy to be approximately 80 million daltons. These supercoiled circular DNA molecules, which have a guanine plus cytosine (G + C) composition of 42%, were concluded to be the extrachromosomal P factor. It was calculated that there is approximately one copy of the P factor per chromosome. A small amount of supercoiled circular DNA was occasionally isolated from the P
−
strains of
V. cholerae
. The function of this component, which has a molecular weight of 40 million daltons, is not known. The molecules found in the P
−
strains were readily distinguished from the P
+
circular molecules by their smaller molecular weight and different G + C composition.
Host Range and Properties of the
Pseudomonas aeruginosa
R Factor R1822
Authors: Olsen Ronald H. , Shipley Patricia
Published: January 2020

R1822, a plasmid specifying multiple drug resistances, has been transferred to a variety of species representative of related and unrelated genera. The host range of the plasmid includes
Enterobacteriaceae
, soil saprophytes,
Neisseria perflava
, and photosynthetic bacteria. With the acquisition of drug resistance(s), these strains became sensitive to a small, ribonuclease-sensitive bacteriophage, designated PRR1, isolated by enrichment from sewage.
Metabolism of
d
-Fructose by
Arthrobacter pyridinolis
Authors: Sobel Mark E. , Krulwich Terry A.
Published: January 2020

Previous studies showed that
Arthrobacter pyridinolis
can transport and utilize
d
-glucose only after prior growth on certain Krebs cycle intermediates. In contrast, we found that
d
-fructose was taken up and metabolized by
A. pyridinolis
without special prior conditions of growth.
d
-Fructose was first converted to
d
-fructose-1-phosphate by a phosphoenolpyruvate (PEP):
D
-fructose phosphotransferase. This activity required both supernatant and pellet fractions from
d
-fructose-grown cells centrifuged at 150,000 ×
g
. The
d
-fructose-1-phosphate formed was converted to
d
-fructose-1, 6-diphosphate. Mutants deficient in PEP:
d
-fructose phosphotransferase and
d
-fructose-1-phosphate kinase, or
d
-fructose-1, 6-diphosphatase (FDPase) were unable to grow on
d
-fructose but retained the normal ability to use
d
-glucose. Mutants forming reduced amounts of FDPase were completely unable to grow on
d
-fructose but were still capable of limited growth on Krebs cycle intermediates. A requirement for higher levels of FDPase for growth on
d
-fructose than for growth on Krebs cycle intermediates was also indicated by the higher specific activities of FDPase in
d
-fructose-grown cells than in cells grown on
l
-malate or amino acids.
Stereospecific Enzymes in the Degradation of Aromatic Compounds by
Pseudomonas putida
Authors: Collinsworth William L. , Chapman Peter J. , Dagley Stanley
Published: January 2020

Two reactions in the catabolism of catechol by
meta
-fission, namely, hydration of 2-oxopent-4-enoate (vinylpyruvate) and aldol fission of the product, are catalyzed by stereospecific enzymes. The absolute configuration of this hydration product was shown to be
l
(
S
)-4-hydroxy-2-oxopentanoate. Vinylpyruvate hydratase, purified almost to homogeneity, had a molecular weight of about 287,000 and was dissociated in sodium dodecyl sulfate, without prior treatment with mercaptoethanol, into a species with an approximate molecular weight of 28,000. The hydratase was highly specific for its substrates; thus, although 2-oxo-
cis
-hex-4-enoate was also hydrated, structurally similar compounds such as the
trans
isomer, vinylacetic and crotonic acids, and the ring-fission products of catechol and methylcatechols were not attacked. Vinylpyruvate hydratase was activated by Mn
2+
ions. On the basis of these observations, a mechanism is proposed which closely resembles that for 4-hydroxy-2-oxopentanoate aldolase. A possible evolutionary connection between functionally related, divalent cation-activated hydro-lyases and aldolases is discussed. It was also demonstrated that
l
-(
S
)-4-hydroxy-2-oxohexanoate is the biologically active enantiomer of this hydroxy acid.
Surface Structure of Intact Cells and Spheroplasts of
Pseudomonas aeruginosa
Authors: Weiss Richard L. , Fraser Dean
Published: January 2020

This report describes the ultrastructural features of
Pseudomonas aeruginosa
after freeze-etching of intact cells and enzymatically prepared spheroplasts. Freeze-etching of intact cells revealed two convex layers of the cell wall and particles within the hydrophobic interior of the cell membrane. Areas of the membrane free of particles were sometimes elevated in the form of rather large dome-shaped structures. Spheroplasts were formed from intact cells by the addition of trypsin to a reaction mixture of lysozyme and ethylenediaminetetraacetic acid. Spheroplasts contained the outer lipoid layer of the cell wall. It was possible to observe this cell wall layer in freeze-etch preparations of spheroplasts. The spheroplast membrane like that of intact cells was cleaved along a central plane to expose particles and particle-free areas.
Close Linkage of the Genes
serC
(for Phosphohydroxy Pyruvate Transaminase) and
serS
(for Seryl-Transfer Ribonucleic Acid Synthetase) in
Escherichia coli
K-12
Authors: Clarke S. J. , Low B. , Konigsberg W. H.
Published: January 2020

Escherichia coli
strain K28, isolated after nitrosoguanidine mutagenesis, was found to be auxotrophic for serine. It was also temperature sensitive for growth as a result of producing an altered seryl-transfer ribonucleic acid (tRNA) synthetase (EC 6.1.1.11,
l
-serine: tRNA ligase [AMP]). The auxotrophy was caused by a mutation in the structural gene for phosphohydroxy-pyruvate transaminase (
serC
), which was distinct from, but closely linked to, the structural gene for seryl-tRNA synthetase (
serS
). We conclude that the relevant genes are in the order
gal-serS-serC-aroA
.
Characterization of Esterases Produced by a Ruminal Bacterium Identified as
Butyrivibrio fibrisolvens
Authors: Lanz Wayne W. , Williams Phletus P.
Published: January 2020

An obligately anaerobic ruminal bacterial isolate was selected from 18 tributyrin-degrading isolates and identified as
Butyrivibrio fibrisolvens
strain 53. The culture in late exponential phase contained enzymes which could be released by sonic disruption. These enzymes degraded substrates at a rate in the order 1-naphthyl acetate (NA) > 1-naphthyl butyrate > 1-naphthyl propionate but did not degrade 1-naphthyl palmitate or 1-naphthyl phosphate. The enzymes on NA were neither stimulated nor inhibited by CoCl
2
, MgCl
2
, and MnCl (each varied from 10
−6
to 10
−4
M). CaCl at 10
−3
M stimulated esterase activity by 16%. Aliphatic substrates were hydrolyzed at a rate in the order triacetin > tributyrin > tripropionin, and ethyl acetate > ethyl formate. Similarly, aromatic fluorescein diesters were degraded at a rate in the order acetyl > propionyl > caproyl > butyryl > capryl > lauryl. Polyacrylamide gel electrophoretic zymograms indicated that the enzyme composite contained cathodally migrating bands. By column chromatography, these enzymes were separated into six NA-degrading fractions. Fraction V contained an esterase which had an optimal temperature of 39 C, a
K
m
of 7.6 × 10
−4
on NA, and a molecular weight of about 66,000. This enzyme was inhibited by paraoxon (41%, 10
−4
M), eserine (17%, 10
−2
M), NaF (17%, 10
−2
M), and diisopropyl fluorophosphate (62%, 10
−4
M) but not by 1-naphthyl
N
-methyl carbamate at 8.4 × 10
−4
M.
Genetic Fine Structure of the Leucine Operon of
Escherichia coli
K-12
Authors: Somers J. M. , Amzallag A. , Middleton R. B.
Published: January 2020

The order of mutational sites in 10 independently isolated leucine auxotrophys of
Escherichia coli
K-12 was determined by three-point reciprocal transductions. The sites of mutation mapped in linear sequence in a cluster; all leucine auxotrophic mutations were cotransducible with mutations in the arabinose operon. The mutations were assigned to four complementation groups by abortive transduction tests, designated D, C, B, and A, reading in a clockwise direction from the arabinose operon. Enzyme analyses showed that strains with a mutation in gene A lacked α-isopropylmalate synthetase activity (EC 4.1.3), and those with a mutation in gene B lacked β-isopropylmalate dehydrogenase activity (EC 1.1.1). It is concluded that the gross structure of the leucine operon in
E. coli
is closely similar to, if not identical with, the gross structure of the leucine operon in
Salmonella typhimurium
.
Synthesis of Ribosomal Ribonucleic Acid During Sporulation of
Bacillus subtilis
Authors: Bonamy C. , Hirschbein L. , Szulmajster J.
Published: January 2020

The incorporation of radioactive uracil into 50
s
and 30
s
ribosomal subunits and ribosomal ribonucleic acid (rRNA) was studied during the growth cycle of different sporogenic and asporogenic strains of
Bacillus subtilis
. It was found that partially synchronized cultures of the strains examined incorporated labeled uracil into the two ribosomal subunit species and rRNA during sporulation and during the stationary phase of the asporogenic strains. Kinetic studies have shown that, compared to vegetative cells, the percentage of uracil incorporated into the ribosomal subunits of cells taken 30 min after the end of exponential growth was decreased by about 25 to 35%. This decrease, however, appeared to be a general characteristic of stationary-phase cells and seems to depend on the nature of the sporulation medium and to some extent on the nature of the strain but not on the sp
+
or sp
−
phenotype of the strain. Moreover, by use of actinomycin D it was shown that the labeled uracil incorporated, in the presence of the drug, during the sporulation period was located in the ribosomal subunits (stable RNA). Based on these results, we concluded that during sporulation ribosomal genes are transcribed and consequently rRNA continues to be synthesized, although to a lesser extent than during vegetative growth. These results are discussed in the light of those obtained by Hussey et al.
Bacterial Cell Division Regulation: Lysogenization of Conditional Cell Division
lon
−
Mutants of
Escherichia coli
by Bacteriophage Lambda
Authors: Walker James R. , Ussery Christine L. , Allen Jane Smith
Published: January 2020

The
lon
−
mutants of
Escherichia coli
grow apparently normally except that, after temporary periods of inhibition of deoxyribonucleic acid synthesis, septum formation is specifically inhibited. Under these conditions, long, multinucleate, nonseptate filaments result. The
lon
−
mutation also creates a defect such that wild-type bacteriophage λ fails to lysogenize
lon
−
mutants efficiently and consequently forms clear plaques on a
lon
−
host. Two lines of evidence suggest that this failure probably results from interference with expression of the λ
cI
gene, which codes for repressor, or with repressor action:-(i) when a
lon
−
mutant was infected with a λ
cII, cIII
, or
c Y
mutant, there was an additive effect between the
lon
−
mutation and the λ
c
mutations upon reduction of lysogenization frequency; and (ii)
lon
−
mutants permitted the growth of the λ
cro
−
mutant under conditions in which the repressor was active. The isolation of λ mutants (λtp) which gained the ability to form turbid plaques on
lon
−
cells is also reported.
Selection of Respiratory Mutants of
Neurospora crassa
Authors: Edwards David L. , Kwiecinski Fabia , Horstmann Jonathan
Published: January 2020

A method is described that permits the isolation of mutants that are defective in mitochondrial respiration. The techniques of inositol-less death and overlay with 2,3,5-triphenyl-2H-tetrazolium chloride are utilized to select for mutant colonies. Colonies that survive inositol-less death and fail to reduce the tetrazolium dye are then tested polarographically for cyanide-sensitive respiration. A preliminary characterization of three mutants obtained by this method is presented. The mutants have been characterized by their cyanide-sensitive respiration rate, growth rate, the state III respiration rate of isolated mitochondria, inhibition of the respiration of isolated mitochondria by cyanide and antimycin A, and cytochrome spectra. All of the mutants described differ from the parent strain in some of these aspects.
Fate of Transforming Deoxyribonucleic Acid After Uptake by Competent
Bacillus subtilis
: Phenotypic Characterization of Radiation-Sensitive Recombination-Deficient Mutants
Authors: Dubnau D. , Davidoff-Abelson R. , Scher B. , Cirigliano C.
Published: January 2020

A collection of 16 isogenic recombination-deficient strains of
Bacillus subtilis
isolated on the basis of sensitivity to methyl methane sulfonate (MMS) or mitomycin C (MC) were characterized phenotypically. All were found to be somewhat sensitive to ultraviolet irradiation, MC, and MMS. The mutants were all blocked in “late” steps in the transformation process and were provisionally grouped into four categories on the basis of the various properties examined. Class I mutants were deficient in transformation and heterologous transduction with phage PBS1 but were transducible with homologous donors at nearly the wild-type frequency. They were blocked in donor-recipient complex (DRC) formation but formed essentially normal amounts of double-strand fragments (DSF) and single-strand fragments (SSF). The class IIa strain was deficient in transformation and PBS1 transduction, and formed DRC which was normal by all available physical and biological criteria. Class IIb mutants were deficient in transformation and PBS1 transduction, and failed to form DRC. They did produce DSF and SSF. Class III mutants were deficient in transformation, were normal in PBS1 transduction, and formed DRC which was physically indistinguishable from that of the Rec
+
parent although with slightly lowered donor-type transforming activity. Class IV strains were deficient in PBS1 transduction but were transformed at nearly the wild-type efficiency. None of the mutant strains was deficient in the adenosine triphosphate-dependent deoxyribonuclease.
Control of F′
lac
Replication in
Escherichia coli
B/r
Authors: Davis Daniel B. , Helmstetter Charles E.
Published: January 2020

The timing of replication of an F′
lac
plasmid during the division cycle of
Escherichia coli
B/r
lac
−
/F′
lac
was examined in relation to the timing of initiation of chromosome replication. This was accomplished by measuring the induction of β-galactosidase and the incorporation of radioactive thymidine into cells at different ages in cultures growing exponentially at various rates. In cells growing with interdivision times of 27, 36, and 55 min, the F′
lac
replicated at various stages in the division cycle but always at approximately the same time as initiation of chromosome replication. In cells growing with an interdivision time of 85 min, the F′
lac
episome replicated midway through the division cycle, whereas chromosome replication initiated at the start of the cycle. Measurements of absorbance at 450 nm per cell suggested that the F′
lac
replicated when the cells reached a mass which was a constant multiple of the number of episomes per cell at each growth rate. In contrast, the mass per cell at initiation of chromosome replication in cells with an 85-min interdivision time was significantly lower than this constant value. A possible explanation for the apparent coupling between F′
lac
replication and initiation of chromosome replication at the higher growth rates, and the lack of coupling at the lowest growth rate, is discussed.
Strand-Specific Nick in Open Circular R-Factor Deoxyribonucleic Acid: Attachment of the Linear Strand to a Proteinaceous Cellular Component
Authors: Morris C. F. , Hershberger C. L. , Rownd R.
Published: January 2020

The fraction of covalently closed circular R-factor R12 deoxyribonucleic acid (DNA) isolated from
Proteus mirabilis
was found to depend upon the pH of the buffer used to suspend the cells at the time of lysis. Examination of the open circular DNA revealed that there is one strand-specific nick per R-factor molecule. This same DNA strand also appeared to be bound to a proteinaceous particulate fraction of the cell.
Growth and Initiation of Protein Synthesis inEscherichia coliin the Presence of Trimethoprim
Authors: Harvey R. J.
Published: January 2020

Escherichia coligrew exponentially at a reduced rate in the presence of 50 or 100 μg of trimethoprim/ml if the low-molecular-weight products of folate metabolism or their precursors (thymidine, purines, methionine, glycine, and pantothenate) were supplied in the medium. Folate metabolism was inhibited 99.9% by these concentrations of trimethoprim, but a low level of formylation of methionyl transfer ribonucleic acid (met-tRNAF) could be detected. However, in a medium containing all major amino acids, nucleosides, and vitamins, formylation of met-tRNAFwas undetectable in the presence of trimethoprim. No other amino-masked amino acids were detected, and methionine remained a major amino-terminal amino acid of mature proteins. met-tRNAFwas rapidly labeled with exogenous methionine and was associated with 30sribosomal subunits and 70sribosomes. It was concluded that initiation of protein synthesis can occur with unformylated met-tRNAFinE. coli. Changes in macromolecular composition were associated with the lack of formylation, in particular a fourfold increase in both met-tRNAFand ribosomal subunits. These changes would tend to compensate for the low specific rate of initiation with unformylated met-tRNAF.
Methanol Metabolism in Pseudomonad C
Authors: Stieglitz B. , Mateles R. I.
Published: January 2020

Cell suspensions of pseudomonad C, a bacterium capable of growth on methanol as sole carbon source, were able to oxidize methanol, formaldehyde, and formate, although the rates of oxidation for the latter two compounds were much slower. The latter compounds also could not serve as sole carbon sources. Through the use of labeled compounds, it was shown that in the presence of methanol, formaldehyde, formate, and bicarbonate were incorporated into trichloroacetic acid-precipitable material. Hexose phosphate synthetase activity was found, indicating the assimilation of methanol via an allulose pathway. No hydroxypyruvate reductase activity was found, nor was any complex membrane structure observed. Such a combination of characteristics has been observed in an obligate methylotroph (PseudomonasW1), but pseudomonad C can utilize a variety of non-methyl substrates.