bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of Isocitrate Lyase: the Basis for Inhibition of Growth of Two
Arthrobacter
Species by Pyruvate
Authors: Wolfson Philip J. , Krulwich Terry A.
Published: January 2020

Growth of
Arthrobacter atrocyaneus
and
A. pyridinolis
on certain growth substrates was found to be inhibited by pyruvate and compounds which can be converted to pyruvate. Growth of
A. atrocyaneus
on acetate, for example, was completely inhibited by 5 m
m
pyruvate; growth of this organism on glucose was less sensitive and growth on succinate was insensitive to inhibition by pyruvate. Growth of a third
Arthrobacter
species,
A. crystallopoietes
, on acetate and other substrates was not inhibited by pyruvate. The site of pyruvate inhibition was shown to be the isocitrate lyase reaction. Glyoxylate, which affords a bypass of this reaction, restored the ability of
A. atrocyaneus
to evolve
14
CO
2
from acetate in the presence of pyruvate. The isocitrate lyases from
A. atrocyaneus
and
A. pyridinolis
were competitively inhibited by concentrations of pyruvate as low as 1 m
m
, whereas the enzyme from
A. crystallopoietes
was unaffected by this concentration of pyruvate. Comparable levels of phosphoenolpyruvate did not inhibit the isocitrate lyases from any of the species. A mutant strain of
A. atrocyaneus
, PW11, which is deficient in isocitrate lyase activity, grew on glucose at a reduced rate that was comparable to the rate of growth of the wild-type strain on glucose plus lactate. Addition of lactate to PW11 did not further reduce its rate of growth on glucose. Thus, the glyoxylate pathway appears to be used as an anaplerotic pathway during growth of
A. atrocyaneus
on glucose. Two other considerations suggest that
A. atrocyaneus
and
A. pyridinolis
, but not
A. crystallopoietes
, may be deficient in the ability to convert pyruvate to 4-carbon acids. First, the former two species accumulate intracellular pyruvate from exogenous
l
-alanine to a much greater extent than does
A. crystallopoietes
. Moreover,
A. atrocyaneus
and
A. pyridinolis
are incapable of growth on lactate as sole source of carbon whereas
A. crystallopoietes
can grow on lactate.
Isolation of Transducing Bacteriophages for the Histidine and Isoleucine-Valine Operons in
Escherichia coli
K-12
Authors: Avitabile Alessandra , Carlomagno-Cerillo Maria S. , Favre Renée , Blasi Francesco
Published: January 2020

In vitro studies have been of great value in elucidating the mechanism of the regulation of several bacterial operons. To obtain a deoxyribonucleic acid preparation enriched for the histidine (
his
) and for the isoleucine-valine (
ilv
) operons, we have isolated bacteriophages carrying the
his
and the
ilv
regions of the
Escherichia coli
chromosome. Transposition of the
his
operon to a site close to the
att80
region of the
E. coli
chromosome has been carried out selecting for integration of a temperature-sensitive F′
his
+
in the
tonB
locus. This transposed strain has been lysogenized with φ80i
λ
. Upon induction of the lysogen, His
+
transductants have been isolated, which, on further induction give rise to HFT (high frequency of transduction) lysates. Preliminary characterization of the transducing phage is reported. The
ilv
operon, carried on an F′ particle, has been fused to an episome carrying the
att80
region. The fused episome has been lysogenized with φ80i λt68. Upon induction of the lysogen, Ilv
+
transductants have been isolated which on further induction give rise to HFT lysates.
Genetic Characterization of a Stable F′
lac
Plasmid
Authors: Macrina Francis L. , Balbinder Elias
Published: January 2020

A mutant F′ plasmid has been isolated in a strain of
Salmonella typhimurium
harboring F
ts114
lac
. This mutant, designated F
lacS
, exhibits unique genetic stability in strains of
S. typhimurium
and
Escherichia coli
. It shows no thermolability and is lost at frequencies of 20 to 100 times less than the wild-type F′
lac
(F42) in the same genetic backgrounds. The F
lacS
is also insensitive to conventional plasmid curing agents, whereas both F
ts114
lac
and F42 are readily cured. The nature of the mutation(s) conferring stability to the F
lacS
is unclear, but plasmid linkage has been established. The high frequency of conjugal transfer of the F
lacS
and its behavior in recombination-deficient strains of
S. typhimurium
and
E. coli
argue against its stability being due to stable chromosomal integration. The F
lacS
is also capable of transferring chromosomal markers in
S. typhimurium
and
E. coli
mating systems. No major differences in chromosomal mobilization have been observed among F42, F
ts114
lac
, and F
lacS
donors of either genus.
Purification and Properties of the Flavine-Stimulated Anaerobicl-α-Glycerophosphate Dehydrogenase ofEscherichia coli
Authors: Kistler W. S. , Lin E. C. C.
Published: January 2020

The anaerobicl-α-glycerophosphate (l-α-GP) dehydrogenase ofEscherichia coliwas purified approximately 40-fold. The activity of the dehydrogenase, although not affected by the addition of pyridine nucleotides, was stimulated three- to fourfold by flavine adenine dinucleotide (Kmabout 10−7m) and up to 10-fold by flavine mononucleotide (Kmabout 10−4m). Maximal activity of the enzyme was found only in the combined presence of saturating concentrations of both flavines (stimulation by a factor of 10 to 15). The dependence of the rate of the reaction on the concentration ofl-α-GP was complex in the presence of both flavines, but in the presence of flavine adenine dinucleotide alone the kinetics were of the Michaelis-Menten type with theKmforl-α-GP being about 10−4m. The product of the reaction was identified as dihydroxyacetone phosphate, and the molecular weight of the dehydrogenase was estimated to be 80,000 ± 10,000. Phenazine methosulfate, menadione and ferricyanide served as artificial acceptors for the dehydrogenase. The enzyme was sensitive to iodoacetate,p-chloromercuribenzoate, andN-ethymaleimide.
Effects of Cyclic Nucleotides and Nucleoside Triphosphates on Stalk Formation in
Caulobacter crescentus
Authors: Schmidt Jean M. , Samuelson Gay M.
Published: January 2020

Extensive stalk elongation in Skl mutants of
Caulobacter crescentus
occurs when they are grown in complete medium. This stalk elongation is less pronounced in synthetic medium with glucose as the sole carbon source than in complex peptone yeast extract medium. Addition of exogenous nucleoside triphosphates (adenosine triphosphate [ATP], guanosine triphosphate [GTP], cytidine triphosphate, and uridine triphosphate) inhibits stalk elongation of the Skl mutants, whereas cyclic guanosine 3′,5′-monophosphate (GMP) stimulates stalk elongation in the Skl strains grown in synthetic glucose medium. Cyclic GMP also produces stalk elongation in wild-type
C. crescentus
and concurrently produces a cell division defect resulting in cellular filament formation. Under conditions tested, cyclic adenosine 3′,5′-monophosphate and dibutyryl cyclic adenosine monophosphate did not enhance stalk elongation. Endogenous ATP and GTP levels in the mutants are significantly lower than corresponding nucleotide concentrations of the parent wild-type strains. Control of syntheses resulting in stalk formation in
C. crescentus
appears to be related to intracellular concentrations of nucleotides, with cyclic GMP as a prominent candidate for an important regulatory role in this aspect of morphogenesis.
Interaction of Genes Controlling Ultraviolet Sensitivity in
Neurospora crassa
Authors: Tuveson R. W.
Published: January 2020

Two independently segregating ultraviolet (UV) sensitivity genes in
Neurospora crassa
interact synergistically resulting in UV sensitivity approximately twice that expected based on an evaluation of the sensitivities of the individual mutants. The mutant genes singly and together reduce photoreactivation (PR) in vivo although a PR enzyme is produced which exhibits normal activity in vitro.
Flagellar Cross-Repolymerization Among Different
Salmonella
Serotypes and
Escherichia coli
Authors: Barden Ned T. , Deibel R. H.
Published: January 2020

Flagellar preparations from several serotypes of
Salmonella
and one strain of
Escherichia coli
were tested for their ability to cross-repolymerize. Repolymerization was found not to be dependent on the antigenic determinants of the flagella.
Isolation and Characterization of a Mutant Colicin E2
Authors: Kennedy Christina , Sodergren Erica
Published: January 2020

Escherichia coli
K-12 colicinogenic for Col E2 yielded a mutant, SK95, that carries a nonsense mutation in the colicin structural gene. A derivative of SK95 that carries an as yet unidentified suppressor mutation produces a colicin E2 that is temperature sensitive (TS). This mutant colicin kills sensitive cells at low temperature but not at high temperature; the colicin adsorbs to cells at high temperature but does not kill them unless the temperature is lowered. Unlike normal colicin E2, which adsorbs rapidly to cells, TS colicin E2 adsorbs slowly over a period of several hours. The biochemical target of colicin E2 is deoxyribonucleic acid (DNA). When acid solubilization of DNA was compared in cells treated with either TS or normal colicin E2, striking differences were observed. Cell killing and acid solubilization of DNA by colicin E2 were shown to be separable events under certain conditions. The results are discussed in relation to the mechanism of action of colicin E2.
Temperature-Dependent Utilization of
meso
-Inositol: a Useful Biotyping Marker in the Genealogy of
Salmonella typhimurium
Authors: Old David C.
Published: January 2020

Salmonella typhimurium
strains from natural sources either ferment or do not ferment
meso
-inositol in peptone water in 24 hr at 37 C. Ninety-five percent of the strains that are designated inositol-nonfermenting on the basis of their phenotype at 37 C ferment inositol when incubated at 25 C. Two classes of temperature-sensitive mutants were detected among the 712 strains of
S. typhimurium
examined. The occurrence of low-temperature fermentation of inositol among wild-type strains of
S. typhimurium
from biotypes 10 through 13 and FIRN suggested a genealogical relationship between these two groups, and that FIRN strains (
fim
−
inl
ts
rha
−
) might have descended from ancestral types like biotype 10 through 13 strains (
fim
+
inl
ts
rha
+
).
Physiological Studies on Ergot: Further Studies on the Induction of Alkaloid Synthesis by Tryptophan and Its Inhibition by Phosphate
Authors: Robbers J. E. , Robertson L. W. , Hornemann K. M. , Jindra A. , Floss H. G.
Published: January 2020

The failure of
l
-leucine to stimulate ergot alkaloid production in a synthetic medium indicates that the previously observed stimulation by tryptophan and tryptophan analogues does not merely represent a nutritional effect. Tryptophan, but not mevalonate or 5-methyltryptophan, is able to overcome the inhibition of alkaloid synthesis by high levels of inorganic phosphate. Therefore, high phosphate levels seem to limit the synthesis of tryptophan; they may, in addition, prevent induction of alkaloid synthesis by preventing accumulation of tryptophan. Experiments which indicate a 2- to 3-fold temporary increase of intracellular free tryptophan and a 20- to 25-fold increase of tryptophan synthetase activity during the transition period between growth and alkaloid production phase are in agreement with the previously postulated induction of alkaloid synthesis by tryptophan. The latter experiments also indicate 4- to 6-fold repression of this enzyme by tryptophan.
Relationship Between Sporulation-Specific 20
S
Ribonucleic Acid and Ribosomal Ribonucleic Acid Processing in
Saccharomyces cerevisiae
Authors: Sogin Stephen J. , Haber James E. , Halvorson Harlyn O.
Published: January 2020

The nature and properties of the 20
S
ribonucleic acid which accumulates only during the sporulation of
Saccharomyces cerevisiae
were examined. The 20
S
ribonucleic acid (RNA) has a base composition considerably different from ribosomal RNA species and is virtually unmethylated. The 20
S
RNA did, however, exhibit approximately 70% homology with 18
S
RNA by RNA-deoxyribonucleic acid filter hybridization competitions. The 20
S
RNA showed a hybridization saturation plateau level 30 to 40% higher than 18
S
, consistent with measurements of the size difference in polyacrylamide gels. Pulse-chase experiments in the presence and absence of cycloheximide indicate that the 20
S
RNA has a presumptive relationship to the 20
S
ribosomal RNA precursor normally observed only in short pulse-labeling in vegetative cells.
Reversal of the Mannitol-Sorbitol Diauxie in
Escherichia coli
Authors: Lengeler J. , Lin E. C. C.
Published: January 2020

In
Escherichia coli
K-12 the proteins involved in the dissimilation of mannitol and sorbitol are specified by two separate gene clusters. The mannitol cluster appears to consist of a regulatory gene
mtlC
, a gene
mtlA
coding an enzyme II complex of the phosphoenolpyruvate phosphotransferase system, and a gene
mtlD
coding a mannitol-1-phosphate dehydrogenase. Three corresponding genes,
sblC, sblA
, and
sblD
, exist for the sorbitol pathway. In both pathways the hexitol captured from the medium and delivered into the cytoplasm as a phosphorylated compound is dehydrogenated to fructose-6-phosphate. The enzyme II complex for sorbitol is able to catalyze the phosphorylation also of mannitol if this substrate is present at high concentrations. Consequently
mtlA
−
mutants lacking the enzyme II complex for mannitol can grow on mannitol either if the sorbitol phosphorylating system is preinduced by sorbitol or if
mtlA
is suppressed by a mutation of
sblC
to constitutivity. In wild-type cells, the induction of the enzymes in the mannitol pathway and dissimilation of the substrate are not prevented by glucose. The sorbitol system, however, is sensitive to glucose and to mannitol as well. In the suppressed strains (
mtlA
−
,
sblC
c
) in which mannitol is utilized through the sorbitol enzyme, glucose becomes effective in restraining the consumption of mannitol, causing a definite diauxie. Moreover, in a mixture of mannitol and sorbitol, the latter is utilized preferentially. This reversal of normal diauxic pattern is consequent to the fact that the enzyme II complex for sorbitol has relatively poor affinity for mannitol.
High-Level Production of β-Galactosidase by
Escherichia coli
Merodiploids
Authors: Fowler Audree V.
Published: January 2020

Two merodiploids of
Escherichia coli
that contain genes for the
lac
operon on both chromosome and episome were tested for production of
lac
enzymes after growth on various carbon sources. The specific activity of β-galactosidase (and of thiogalactoside transacetylase) was about twice that from haploid cells when grown on glycerol. With succinate as carbon source, the specific activity increased by an additional factor of 3. Up to 25% of the soluble cell protein is β-galactosidase in these strains, one of which is inducible and the other constitutive. The enzyme is purified easily in high yield by ammonium sulfate fractionation and electrophoresis.
Effects of Growth Inhibitors and Ultraviolet Irradiation on F Pili
Authors: Novotny Charles P. , Taylor Paula F. , Lavin Karen
Published: January 2020

The effects of chloramphenicol, nalidixic acid, mitomycin C, NaCN, and ultraviolet irradiation at 253.7 nm on F pili production by
Escherichia coli
cells was studied by electron microscopy. The results show that cells contain pools of pili protein, and that assembly does not require synthesis of protein or deoxyribonucleic acid (DNA). NaCN (2 × 10
−2
m
) prevents the reappearance of pili and causes existing pili to disappear quickly from the cell surface. This suggests that energy is used in the assembly of pili and to retain pili on the cell. Cells irradiated with high doses (10
4
ergs/mm
2
) of 253. 7 nm light produce fewer pili, and these are shorter than normal. Dose-response curves for number of pili per cell and length of pili resemble single hit kinetics, showing 37% survival at 10
4
ergs/mm
2
and 2 × 10
4
ergs/mm
2
, respectively. This suggests that DNA is at the site where pili are produced, and that it may be involved in the assembly of pili.
Heterofermentative Carbohydrate Metabolism of Lactose-Impaired Mutants ofStreptococcus lactis
Authors: Demko G. M. , Blanton S. J. B. , Benoit R. E.
Published: January 2020

Two mutants ofStreptococcus lactisATCC 11454 have been isolated which possess an impaired lactose-fermenting capacity; galactose utilization is also affected, but to a lesser extent. Although the Embden-Meyerhof-Parnas pathway is the major, if not the sole, pathway of carbohydrate metabolism in the three strains, the fermentation end products of the mutants are dramatically different from the typical homolactic pattern of the wild type. Under conditions of low oxygen tension and growth-limiting lactose concentrations, mutant strain T-1 produces largely formic acid, acetic acid (2:1), and ethanol rather than lactic acid. Aerated cultures produce acetic acid, CO2(1:1), acetyl-methylcarbinol, and diacetyl. When the mutants use galactose as an energy source, lactic acid is the major end product, but significant heterofermentative activity is observed. The aberrations responsible for the mutant phenotypes reside in the proteins which catalyze the transport and hydrolysis of galactosides. It is hypothesized that the impaired transport system of the mutants reduces the intracellular pool of glycolytic intermediates below that of the wild type. Since fructose-1, 6-diphosphate is an activator of lactic dehydrogenase inS. lactis, lactic acid production is reduced, and pathways leading to the formation of other products are expressed.
Turnover of Phospholipids in an Unsaturated Fatty Acid Auxotroph of
Escherichia coli
Authors: Crowfoot Peter D. , Oka Tetsuo , Esfahani Mojtaba , Wakil Salih J.
Published: January 2020

The membrane phospholipids of an unsaturated fatty acid auxotroph of
Escherichia coli
were found to undergo turnover. These phospholipids were excreted into the culture medium, and were replaced in the cell with newly synthesized phospholipids. Phospholipids of growing cells supplemented with elaidic acid underwent rapid turnover, while those of cells supplemented with oleate, or
cis
-vaccenate plus palmitoleate, underwent slow turnover. Starvation for required amino acids stimulated this turnover in the latter two cases. Protein was also lost from growing cells. However, after amino acid starvation this loss ceased while phospholipid turnover continued. Electron micrographs of growing cells indicated that large pieces of membrane-like material were separating from the cell surface.
Formation of Polyisoprenol Phosphate Glucose in
Shigella flexneri
Authors: Jankowski W. , Chojnacki T. , Janczura Ewa
Published: January 2020

Lipid-linked glucose is formed from uridine diphosphate-glucose and ficaprenol phosphate only in strains of
Shigella flexneri
with glucosylated O antigen.
Temperature-Sensitive Relaxed Phenotype in a Stringent Strain of
Escherichia coli
Authors: Atherly Alan G.
Published: January 2020

A temperature-sensitive elongation factor G (EF-G) mutation carried by a
rel
strain of
Escherichia coli
was transferred to a
rel
+
strain. The recombinant (AA-10) was found to be temperature-sensitive “relaxed” for ribonucleic acid (RNA) regulation. However, when a temperature-sensitive EF-G is present in a strain temperature-sensitive for valyl-transfer RNA (tRNA) synthetase, this new strain (AA-16) is no longer temperature-sensitive “relaxed” for RNA regulation. In strain AA-10, all tRNAs remain fully charged, and in AA-16 tRNA
val
becomes completely discharged at the nonpermissive growth temperature. Also, synthesis of ppGpp is not observed in strain AA-10 at 42 C but is observed at 42 C in strain AA-16.
Serological Relatedness of Bacterial Deoxyribonucleic Acid Polymerases
Authors: Tafler Susan W. , Setlow Peter , Levine Lawrence
Published: January 2020

A number of bacterial species have been surveyed for serological activities with antiserum to
Escherichia coli
B deoxyribonucleic acid (DNA) polymerase I (EC 2.7.7.7.). The degree of serological cross-reaction is taken as a measure of relatedness of both the enzyme molecules from various species and the bacterial species themselves. Extracts were assayed by complement fixation only after treatment with deoxyribonuclease, since DNA bound to DNA polymerase alters the serological activity of the enzyme. Antiserum to
E. coli
DNA polymerase I did not react with either purified
E. coli
DNA polymerase II or the phage T4-induced DNA polymerase.
Effect of Lysozyme on Enterococcal Viability in Low Ionic Environments
Authors: Metcalf Robert H. , Deibel R. H.
Published: January 2020

The action of lysozyme on the enterococcal cell differed markedly as a function of the ionic strength of the environment. In high ionic environments (I ≃ 0.3), the traditionally slow lytic response and decrease in viability were noted. In a low ionic environment the majority of the cell wall was hydrolyzed, but cellular integrity was preserved and almost all cellular protein, deoxyribonucleic acid and ribonucleic acid remained with the lysozyme-cell complex. However, under these conditions, lysozyme inactivated energy-yielding metabolism, and a rapid extensive loss of viability was observed. Some other basic compounds without lytic activity on the cell wall also effected a substantial reduction in viability. The data suggest that lysozyme acts on the cell membrane to effect disruption of cellular metabolism.
Partial Purification and Properties of the Pyruvate-Uridine Diphospho-
N
-Acetylglucosamine Transferase from
Staphylococcus epidermidis
Authors: Wickus Gary G. , Strominger Jack L.
Published: January 2020

A method for the partial purification of the pyruvate-uridine-diphospho-
N
-acetylglucosamine transferase from
Staphylococcus epidermidis
is presented. Some properties of the enzyme are discussed.
Reversal by Aromatic Amino Acids of 2-Thiazole-
dl
-Alanine Inhibition of
Salmonella typhimurium
Authors: Bahramian M. B. , Middleton R. B.
Published: January 2020

Of 21
l
-amino acids tested (at 1.2 × 10
−4
m
), only histidine and the aromatic amino acids (phenylalanine, tryptophan, and tyrosine) protect
Salmonella typhimurium
strains from inhibition of growth and immediately reverse the growth inhibition by 5 × 10
−4
m
2-thiazole-
dl
-alanine.
Degradation of Protocatechuate in
Pseudomonas testosteroni
by a Pathway Involving Oxidation of the Product of
Meta
-Fission
Authors: Dennis D. Adele , Chapman Peter J. , Dagley Stanley
Published: January 2020

In addition to catalyzing the hydrolysis of 4-carboxy-2-hydroxymuconic semialdehyde, formed by
meta
-fission of protocatechuate,
Pseudomonas testosteroni
also possesses a nicotinamide adenine dinucleotide(phosphate)-linked dehydrogenase for this compound and can degrade protocatechuate to pyruvate and oxaloacetate.
Genetic Analysis of Repair of Ultraviolet Damage by Competent and Noncompetent Cells of
Bacillus subtilis
Authors: Hadden Charles T. , Billen Daniel
Published: January 2020

The repair of ultraviolet (UV) damage in
Bacillus subtilis
W23T
−
has been studied by transformation with deoxyribonucleic acid (DNA) extracted from irradiated cells before and after repair. The extent of repair of genetic markers by donor cells after low or moderate doses of UV was found to be related only to the initial degree of inactivation. After a very high dose, further inactivation occurred, also in proportion to initial damage. In addition, the competent recipient cells were shown to repair approximately 75% of the damage in transforming DNA. The sensitivities of markers irradiated either in vivo or in vitro appeared to be related to map position, the more proximal markers showing a greater resistance to UV inactivation.
Control of Pantothenate Accumulation inAgrobacterium tumefaciens
Authors: Kaneshiro Tsuneo , Arthur Larry O. , Nickerson Kenneth W.
Published: January 2020

Two pantothenate-requiring mutants ofAgrobacterium tumefacienshave been isolated. One of them (strain WMP-1) is unusual in that growth levels equivalent to the parent strain are achieved only when the medium is additionally supplemented with aspartate or another compound related to the tricarboxylic acid cycle. Extracts of cells grown on limiting aspartate were found to contain four times more14C-pantothenate than those grown at optimal aspartate concentrations. This difference was found in both the perchloric acid-soluble and -insoluble fractions, presumably the coenzyme A pool and acyl carrier protein, respectively. These findings are discussed in terms of membrane integrity and the control of fatty acid biosynthesis.
Biosynthesis of Glycogen and Starch in
Cryptococcus laurentii
Authors: Schultz John C. , Ankel Helmut
Published: January 2020

Cells of
Cryptococcus laurentii
, when grown in liquid culture on 2% glucose close to neutral
p
H, showed glycogen granules throughout the cytoplasm. Glycogen levels of
C. laurentii
cells reached maximal levels just before onset of stationary phase. Concomitantly, a sharp rise in total and specific activity of glycogen synthetase was observed. Conversely, glycogen phosphorylase reached its highest specific activity approximately 3 hr after the glycogen peaked and remained high until most of the endogenous glycogen was utilized. Uridine diphosphoglucose pyrophosphorylase activity was always an order of magnitude higher than glycogen synthetase during log phase, but fell off rapidly after the cells reached stationary growth. Kinetic properties of the glycogen synthetase showed that the enzyme is always activated by glucose-6-phosphate, although the degree of activation by glucose-6-phosphate was found to be somewhat variable. The accelerated uptake of glucose commencing with the onset of stationary phase is explained by the rapid formation of extracellular acidic polysaccharide, which continues as long as there is glucose in the medium. In cells grown at
p
H 3.4, where no detectable extracellular acidic polysaccharide was formed, glucose uptake drastically declined when the cells reached stationary phase. These cells also contained glycogen-like granules in the cytoplasm. The evidence presented indicates that these granules are in fact glycogen, and that its structure does not resemble that of the starch excreted by cells grown at acidic
p
H.
Adenosine Triphosphate-Dependent Deoxyribonuclease from
Diplococcus pneumoniae
: Fate of Transforming Deoxyribonucleic Acid in a Strain Deficient in the Enzymatic Activity
Authors: Vovis Gerald F.
Published: January 2020

The adenosine triphosphate-dependent deoxyribonuclease is required for wild-type levels of deoxyribonucleic acid (DNA) repair and genetic recombination. In an attempt to determine the physiological function of this enzyme in pneumococcal transformation, the fate of transforming DNA was followed in a wild-type strain and in a strain lacking the enzymatic activity. The qualitative and quantitative findings were closely comparable in the two strains through the step of physical association of a single strand of donor DNA with the recipient chromosome. These results are interpreted to mean that the enzyme may be involved in the subsequent hypothetical removal of excess polynucleotide sequences during conversion of the presumed hydrogen-bonded intermediate into a covalently linked recombinant structure.
Host Specificity of
Salmonella typhimurium
Deoxyribonucleic Acid Restriction and Modification
Authors: Slocum Harvey , Boyer Herbert W.
Published: January 2020

The restriction and modification genes of
Salmonella typhimurium
which lie near the
thr
locus were transferred to a restrictionless mutant of
Escherichia coli
. These genes were found to be allelic to the
E. coli
K, B, and A restriction and modification genes.
E. coli
recombinants with the restriction and modification host specificity of
S. typhimurium
restricted phage λ that had been modified by each of the seven known host specificities of
E. coli
at efficiency of plating levels of about 10
−2
. Phage λ modified with the
S. typhimurium
host specificity was restricted by six of the seven
E. coli
host specificities but not by the RII (
fi
−
R-factor controlled) host specificity. It is proposed that the restriction and modification enzymes of this
S. typhimurium
host specificity have two substrates, one of which is a substrate for the RII host specificity enzymes.
Chromatographically Fractionated Complementary Strands of
Bacillus subtilis
Deoxyribonucleic Acid: Transformation of Hybrids
Authors: Rudner Rivka , Remeza Virgilija
Published: January 2020

The annealing properties as measured by the restoration of transforming activity and hypochromicity of methylated albumin-kieselguhr (MAK)-fractionated complementary strands of
Bacillus subtilis
deoxyribonucleic acid (DNA) are presented. Temperature-absorbance measurements performed on annealed mixtures of various L and H strand fractions indicated the existence of a complementarity gradient between the two MAK peaks. The markers
purA16, leu-8, metB
5
,
thr-5
, and the linked marker
hisB
2
-
try-2
exhibited different bimodal distributions on MAK columns. The transforming efficiency of heteroduplex mixtures, prepared by cross-annealing resolved complementary strands of wild-type and recipient DNA, was compared. The transforming efficiency of the wild-type L and H strands was equal in one preparation and unequal in a second preparation. It was found that in the second strand preparation the heteroduplex DNA containing the H strand from wild type was more efficient for all of the markers tested. The variations in transforming efficiencies of the complementary strands in heteroduplex molecules reported here and by others are due in part to strands of unequal length and probably to the self-annealing property of the H strands. At present, no conclusion could be made regarding the existence of strand selection bias during integration of donor DNA in competent
B. subtilis
cells.
Evidence for the Existence of Two Arginyl-Transfer Ribonucleic Acid Synthetase Activities in
Escherichia coli
Authors: Yem D. W. , Williams L. S.
Published: January 2020

Two arginyl-transfer ribonucleic acid (tRNA) synthetase (EC 6.1.1.13, arginine: ribonucleic acid ligase adenosine monophosphate) activities were found in extracts of
Escherichia coli
strains AB1132 and NP2. The two arginyl-tRNA synthetase activities in extracts of strain AB1132 were found to be separable by diethylaminoethyl-cellulose column chromatography, Sephadex column fractionation, and by sucrose density gradient centrifugation. In addition, in the standard assay using extracts of strain AB1132 there were two
p
H optima for arginyl-tRNA synthetase activity. Furthermore, when arginyl-tRNA synthetase of strain NP2 was fractionated by hydroxylapatite column chromatography, two activities were observed which were similar to those of strain AB1132.
Involvement of the
recB-recC
Nuclease (Exonuclease V) in the Process of X-Ray-Induced Deoxyribonucleic Acid Degradation in Radiosensitive Strains of
Escherichia coli
K-12
Authors: Youngs David A. , Bernstein I. A.
Published: January 2020

The
ras, polA, exrA, recA
, and
uvrD3
strains of
Escherichia coli
K-12 degrade their deoxyribonucleic acid more extensively than wild-type strains after X irradiation. The relationship of the
recB-recC
nuclease (exonuclease V) to the degradation process in these strains was determined by comparing the degradation response of the original strains with that of strains containing an additional
recB21
or
recC22
mutation. The initial rate of degradation in
ras, polA12, exrA
, and
recA13
strains after an exposure of 20 to 30 kR was reduced more than 10-fold by the presence of an additional
recB21
or
recC22
mutation. The extent of degradation in these irradiated strains after 90 to 120 min of incubation was reduced two- to fivefold. In the
uvrD3
strain, a
recC22
mutation caused a fourfold decrease in initial degradation rate and reduced the extent of degradation after 90 min of incubation by a factor of 1.6. The results are consistent with the statement that the degradation process is normally dependent on exonuclease V activity. However, the observation that 10 to 30% degradation always occurred even in
recB
or
recC
strains, which lack this enzyme, suggests that alternative degradation mechanisms exist.
Isolation and Characterization of a Regulatory Mutant of an Aminoacyl-Transfer Ribonucleic Acid Synthetase in
Escherichia coli
K-12
Authors: Clarke S. J. , Low B. , Konigsberg W.
Published: January 2020

From
Escherichia coli
strain K28, which is temperature sensitive for growth because of a mutation in its seryl-transfer ribonucleic acid (tRNA) synthetase gene (
serS
), temperature-resistant mutants were selected which were found to have a fivefold higher level of seryl-tRNA synthetase than the parent strain. The “high-level” character was found to be genetically stable and is due to a mutation in a locus denoted
serO
. This locus was found to be very closely linked to
serS
on the genetic map, and the relative gene order was concluded to be
serS-serO-serC
. In a
serO
−
strain, the normal dependence of seryl-tRNA synthetase (SerRS) activity on changes of exogenous serine concentration was not observed. In a stable heterozygous merodiploid, the
serO
−
mutation is still expressed, i.e., it is
cis
dominant. These results strongly suggest that
serO
is an operator site involved in the control of the
serS
gene.
Distinct Kynureninase and Hydroxykynureninase Activities in Microorganisms: Occurrence and Properties of a Single Physiologically Discrete Enzyme in Yeast
Authors: Shetty A. S. , Gaertner F. H.
Published: January 2020

(i)
Saccharomyces cerevisiae
grown in the presence of 1.0 mM
l
-tryptophan slowly excreted fluorescent material that was chromatographically identifiable as 3-hydroxyanthranilate but did not excrete detectable amounts of anthranilate nor rapidly deplete the medium of
l
-tryptophan. Under similar growth conditions,
Neurospora crassa
rapidly excretes anthranilate and rapidly depletes the medium of
l
-tryptophan. (ii) Chromatographic analysis of crude extracts from yeast revealed a single kynureninase-type enzyme whose synthesis was not measurably affected by the presence of tryptophan in the medium. Previous studies have provided evidence for two kynureninase-type enzymes in
N. crassa
, an inducible kynureninase and a constitutive hydroxykynureninase. (iii) Kinetic analysis of the partially purified yeast enzyme provided Michaelis constants for
l
-3-hydroxykynurenine and
l
-kynurenine of 6.7 × 10
−6
and 5.4 × 10
−4
M, respectively. This and other kinetic properties of the yeast enzyme are comparable to those reported for the constitutive enzyme from
N. crassa
. (iv) These findings suggest that
S. cerevisiae
has in common with
N. crassa
the biosynthetic enzyme hydroxykynureninase but lacks the catabolic enzyme kynureninase. Therefore, it can be predicted that, unlike
N. crassa, S. cerevisiae
does not carry out the tryptophan-anthranilate cycle. Distinct kynureninase-type enzymes may exist in other microorganisms and in mammals.
Action of Yeast Killer Factor: a Resistant Mutant with Sensitive Spheroplasts
Authors: Bussey Howard , Sherman Doreen , Somers J. M.
Published: January 2020

Yeast killer factor proteins bind to cells of both sensitive and killer-producing strains, although the latter are immune to killer action. Spheroplasts prepared from sensitive cells bind less than 1% of the killer bound to whole cells, but remain fully sensitive to killer. This finding and those obtained from binding studies of partially purified, radioactive killer protein suggest that most of the toxins remain bound to the yeast cell wall and do not function further in the killing process. A killer-resistant mutant R
18
was isolated from a sensitive strain. Whole cells of the mutant were unable to bind killer and were fully resistant. In contrast, spheroplasts of R
18
were fully sensitive to killer. These data suggest that the sites exposed to killer in spheroplasts are distinct from those on the cell wall. These wall sites appear to be necessary for killer action in whole cells.
Inhibition of Transformation in Group H Streptococci by Lysogeny
Authors: Parsons C. Lowell , Ranhand Jon M. , Leonard Carmen G. , Colon Alba E. , Cole Roger M.
Published: January 2020

Group H streptococcal strains Challis and WE4 were lysogenized with a bacteriophage isolated from strain Channon, after which their capacity for transformation to streptomycin and rifampin resistance was reduced by three orders of magnitude. The probable reason is the inability of the lysogenized strains to bind deoxyribonucleic acid irreversibly, even though they exhibit earlier stages of competence development during a competence regimen.
5-Fluoropyrimidine-Resistant Mutants of Pneumococcus
Authors: Bean Barry , Tomasz Alexander
Published: January 2020

Three classes of 5-fluorpyrimidine-resistant mutants of
Diplococcus pneumoniae
have been characterized. The mutant strain
upp
is resistant to high concentrations of the fluoropyrimidine bases fluorouracil (FU) and fluorocytosine (FC); strain
upp
has a defective uridine monophosphate pyrophosphorylase. The mutant strain
udk
is resistant to inhibition by fluorouridine (FUR) and exhibits defective uridine kinase activity. The mutant strain
fun
is resistant to inhibition by the nucleosides fluorodeoxyuridine, fluorodeoxycytidine, and FUR, but shows normal activity for all pyrimidine pathway enzymes tested. This strain may be defective in the activity of a transport system that governs the cellular uptake of pyrimidine ribo- and deoxyribonucleosides. Biochemical studies on wild-type and fluoropyrimidine-resistant pneumococci are discussed with respect to the transport and early metabolism of preformed pyrimidine precursors by this organism.
Selective Utilization of Pyrimidine Deoxyribonucleosides for Deoxyribonucleic Acid Synthesis in Pneumococcus
Authors: Bean Barry , Tomasz Alexander
Published: January 2020

When pyrimidine deoxyribonucleosides are supplied to growing cultures of
Diplococcus pneumoniae
, they are selectively used for incorporation into deoxyribonucleic acid (DNA). Differently labeled molecules of deoxyuridine, thymidine, and deoxycytidine were used to study the precursor pathways of this organism. Each of these preformed pyrimidine deoxynucleosides is incorporated intact (i.e., without cleavage of the glycosidic bond) and is predominantly recoverable as DNA thymidine. During the utilization of deoxycytidine and deoxyuridine by pneumococci, large proportions of the available precursor are converted to free thymidine, which is secreted back into the growth medium. The biochemical pathways for selective incorporation into DNA and the regulation of concentrations of intracellular thymidine compounds by excretion of free thymidine are discussed.
Requirement of Adenosine-3′, 5′-Cyclic Monophosphate for
l
-Arabinose Isomerase Synthesis in
Escherichia coli
Authors: Nakazawa Teruko , Yokota Takeshi
Published: January 2020

Adenosine-3′, 5′-cyclic monophosphate (cyclic AMP) is essential for the synthesis of
l
-arabinose isomerase in
Escherichia coli
. Cyclic AMP appears to be required for the transcription of deoxyribonucleic acid into messenger ribonucleic acid (RNA), since the enzyme synthesis is not observed in induced cells to which cyclic AMP is added after messenger RNA synthesis is arrested by rifampin or after inducer removal.
Responses of Indigenous Microorganisms to Soil Incubation as Viewed by Transmission Electron Microscopy of Cell Thin Sections
Authors: Bae H. C. , Casida L. E.
Published: January 2020

Air-dried soils were adjusted to 50% moisture-holding capacity and incubated for 2 weeks at 30 C. Samples were removed at intervals, and their total microbial populations were physically separated and concentrated from the soil debris for sectioning and ultrastructure examination. Although the total numbers of cell sections in these preparations remained relatively constant during the soil incubations, the percentages of dwarf cells (≤0.3 μm in diameter), minute cells (≤0.2 μm in diameter), and cells with a cystlike structure decreased with time followed by a slow increase. During this period, a corresponding increase and decrease occurred in the percentages of cells in the 0.3- to 0.5-μm diameter range, but dividing cells were rarely observed. The percentages of spores and of cells with electron-transparent areas also increased and then decreased during incubation. When nutrients were added to these soils, the initial increases in cell size occurred at what appeared to be a faster rate. But this probably was related to a corresponding increase in total cell numbers which also occurred. The responses of the spores, cystlike cells, and cells with electron-transparent areas to nutrient additions were not consistent although all conditions of incubation, regardless of nutrient addition, increased the occurrence of an enlarged diffuse intine-like layer for the cystlike cells. In addition to the above, incubated soils contained cells, which were mainly in the 0.3- to 0.5-μm cell diameter range, that had an internal membrane surrounding the general area of the nuclear material. Changes in additional fine structure features of the microbial populations are described.
Transfection of Group H Streptococci
Authors: Parsons C. Lowell , Cole Roger M.
Published: January 2020

Transfection of streptococci is reported here for the first time.
Genetic Analysis of Ribonucleic Acid Polymerase Mutants of
Bacillus subtilis
Authors: Haworth Stephen R. , Brown Lyle R.
Published: January 2020

Deoxyribonucleic acid-dependent ribonucleic acid polymerase mutants of
Bacillus subtilis
strain Marburg were isolated after mutagenesis of spores with ethyl methane sulfonate. Genetic analysis by PBS1-mediated transduction and by transformation indicated that mutations responsible for all of the four phenotypic classes studied (rifampin resistance, streptovaricin resistance, streptolydigin resistance, and temperature sensitivity) were clustered close to the
cysA14
locus. Three-factor transformation analysis has indicated the most probable marker order as follows: Rif
R
(Stv)
R
-Std
R
-Ts
418
-Ts
427
. In addition, further characterization of the classical group I reference marker,
cysA14
, is reported.
Gram Characteristics and Wall Ultrastructure of
Arthrobacter crystallopoietes
During Coccus-Rod Morphogenesis
Authors: Ward C. M. , Claus G. W.
Published: January 2020

Arthrobacter crystallopoietes
growing exponentially as cocci were changed to rods by adding succinate to the medium. Cells were sampled before, during, and after this transition for Gram-staining and ultrastructural studies. Cells were Gram stained by the standardized method of Bartholomew, and all samples were fixed and prepared for thin sectioning in an identical manner. Cocci were gram positive, and thin sections demonstrated a gram-positive type of cell wall having an average thickness of 31 nm. Cells sampled during morphogenesis appeared as cocci with most having a single rodlike projection. The coccus portion of these transition cells was gram positive and bound by a gram-positive type of wall having an average thickness of 29 nm. The rodlike projection of the transition cells appeared to be gram negative; it was also surrounded by a gram-positive type of wall, but its average thickness was only 22 nm. Gram-negative rods of the type species,
Arthrobacter globiformis
, were also examined and found to produce a gram-positive type of wall with a 19-nm average thickness. Evidence for the trilaminar region, characteristic of most gram-negative bacterial cell walls, was totally lacking in both species. These results suggest that variations in cell wall thickness may be an important contributing factor to the variable Gram-staining characteristics of this genus.
CO
2
Reduction to Formate in
Clostridium acidi-urici
Authors: Thauer R. K.
Published: January 2020

Cell-free lysates of
Clostridium acidi-urici
catalyze the reduction of CO
2
to formate in the presence of reduced ferredoxin and nicotinamide adenine dinucleotide, reduced form.
Transformation of Germinated Spores of
Bacillus subtilis
on Agar Plates
Authors: Tanooka Hiroshi
Published: January 2020

l
-Alanine-germinated spores of
Bacillus subtilis
developed a competence on agar plates after 10 h of incubation. Addition of marker amino acid to the plates was required for the transformation.
Properties of a
d
-Glutamic Acid-Requiring Mutant of
Escherichia coli
Authors: Lugtenberg E. J. J. , Wijsman H. J. W. , van Zaane D.
Published: January 2020

Some properties of a
d
-glutamic acid auxotroph of
Escherichia coli
B were studied. The mutant cells lysed in the absence of
d
-glutamic acid. Murein synthesis was impaired, accompanied by accumulation of uridine-5′-diphosphate-
N
-acetyl-muramyl-
l
-alanine (UDP-MurNac-
l
-Ala), as was shown by incubation of the mutant cells in a cell wall medium containing
l
-[
14
C]alanine. After incubation of the parental strain in a cell wall medium containing
l
-[
14
C]glutamic acid, the acid-precipitable radioactivity was lysozyme degradable to a large extent. Radioactive UDP-MurNac-pentapeptide was isolated from the
l
-[
14
C]glutamic acid-labeled parental cells. After hydrolysis, the label was exclusively present in glutamic acid, the majority of which had the stereo-isomeric
d
-configuration. Compared to the parent the mutant incorporated less
l
-[
14
C]glutamic acid from the wall medium into acid-precipitable material. Lysozyme degraded a smaller percentage of the acid-precipitable material of the mutant than of that of the parent. No radioactive uridine nucleotide precursors could be isolated from the mutant under these conditions. Attempts to identify the enzymatic defect in this mutant were not successful. The activity of UDP-MurNac-
l
-Ala:
d
-glutamic acid ligase (ADP; EC 6.3.2.9) (
d
-glutamic acid adding enzyme) is not affected by the mutation. Possible pathways for
d
-glutamic acid biosynthesis in
E. coli
B are discussed.
Penicillin-Binding Component of
Bacillus cereus
Authors: Aten Raymond F. , Day Richard A.
Published: January 2020

14
C-penicillin is irreversibly bound by
Bacillus cereus
569. Incubation of penicillin-treated cells in a cell wall digestion medium results in solubilization of approximately 60% of the irreversibly bound lable. The extent of the solubilization is the same when cells are prepared by either a cold or 37 C treatment procedure. However, spheroplasts prepared by the cold treatment are leaky. When the resulting spheroplasts are incubated in supplemented medium, reduced rates and levels of penicillinase synthesis, relative to induced whole-cell controls, are observed. Spheroplasts from both cold and 37 C prepared cells exhibit this phenomena, although the spheroplasts from 37 C prepared cells synthesized approximately sixfold higher levels of penicillinase. The size distribution of the label solubilized during the preparation of spheroplasts was examined by using Bio Gel P-150 columns. Although no label appeared in the exclusion volume fractions when the cell wall digest of the 37 C treated cells was chromatographed, approximately 10% of the label from cold-treated cells did appear. These results suggest that the presence of irreversibly bound penicillin is required for the synthesis of induced levels of penicillinase and that the irreversibly bound penicillin can be solubilized as a labile complex with material which is excluded from BioGel P-150. It may be concluded that the penicillin-binding lipoprotein complex which has been previously observed is the penicillin-specific binding site. However, the location of this complex in relation to the cell membrane could not be determined.