bluuebunny/crossref_metadata_2025 huggingface dataset:
Fate of Donor Deoxyribonucleic Acid in a Highly Transformation-Deficient Strain of
Haemophilus influenzae
Authors: Kooistra Jan , Venema Gerard
Published: January 2020

A transformation-deficient strain of
Haemophilus influenzae
(efficiency of transformation 10
4
-fold less than that of the wild type), designated TD24, was isolated by selection for sensitivity to mitomycin C. In its properties the mutant was equivalent to
recA
type mutants of
Escherichia coli
. The TD24 mutation was linked with the
str-r
marker (about 30%) and only weakly linked with the
nov
-r2.5 marker. The uptake of donor deoxyribonucleic acid (DNA) was normal in the TD24 strain, but no molecules with recombinant-type activity (molecules carrying both the donor and the resident marker) were formed. In the mutant the intracellular presynaptic fate of the donor DNA was the same as that in the transformation-proficient (wild-type) strain, and the radioactive label of the donor DNA associated covalently with the recipient chromosome in about the same quantity as in the wild type. However, many fewer donor atoms were associated with segments of the mutant's recipient chromosome as compared with segments of the wild-type chromosome. In the mutant the association was accompanied by complete loss of donor marker activity. The lack of donor marker activity of the donor-recipient complex of DNA isolated from the mutant was not due to lack of uptake of the complex by the second recipient and its inability to associate with the second recipient's chromosome. Because the number of donor-atom-carrying resident molecules was higher than could be accounted for by the lengths of presynaptic donor molecules, we favor the idea that the association of donor DNA atoms with the mutant chromosome results from local DNA synthesis rather than from dispersive integration of donor DNA by recombination.
Genetic Analysis of
Salmonella minnesota
R Mutants with Defects in the Biosynthesis of the Lipopolysaccharide Core
Authors: Jousimies Hannele , Mäkelä P. Helena
Published: January 2020

A set of R (rough) mutants, in which the synthesis of the cell wall lipopolysaccharide is defective, were analyzed genetically. These same
Salmonella minnesota
mutants have been used extensively in biochemical studies. By combining the information from all these studies, we obtained a complete genetic description of many of these mutants. Most of them turned out to be double
rfe rfa
mutants in which the
rfe
mutation (close to
ilv
) accounts for inability to synthesize O-specific structures and the
rfa
mutation accounts for defects in the synthesis of the core and, thus, for the lipopolysaccharide chemotype. These mutants demonstrate that in
S. minnesota
of O group L, as well as in
S. typhimurium
of the O group B, the
rfb
gene cluster close to
his
determines the synthesis of the O-specific side chain of the lipopolysaccharide, and the
rfa
genes in a cluster close to
pyrE
determine the synthesis of the lipopolysaccharide core. Phosphorylation of the core is determined by a
rfaP
gene also in this cluster and so far identified only by these
S. minnesota
mutants. In addition, the
rfe
gene(s) close to
ilv
is required for O-side chain synthesis in
S. minnesota
but not in
S. typhimurium
.
Replication of Deoxyribonucleic Acid in
Escherichia coli
C Mutants Temperature Sensitive in the Initiation of Chromosome Replication
Authors: Sakai Hiroshi , Hashimoto Seiji , Komano Tohru
Published: January 2020

An
Escherichia coli
HF4704S mutant temperature sensitive in deoxyribonucleic acid (DNA) synthesis and different from any previously characterized mutant was isolated. The mutated gene in this strain was designated
dnaH
. The mutant could grow normally at 27 C but not at 43 C, and DNA synthesis continued for an hour at a decreasing rate and then ceased. After temperature shift-up, the increased amount of DNA was 40 to 50%. When the culture was incubated at 43 C for 70 min and then transferred to 27 C, DNA synthesis resumed after about 50 min, initiating synchronously at a fixed region on the bacterial chromosome. The initiation step in DNA replication sensitive to 30 μg of chloramphenicol per ml occurs synchronously before the resumption of DNA replication after the temperature shift-down, being completed about 30 min before the start of DNA replication. When the cells incubated at 27 C in the presence of 30 μg of chloramphenicol per ml after the temperature shift-down to 27 C were transferred to 43 C with simultaneous removal of the antibiotic, no resumption of DNA replication was observed. When the culture was returned to 43 C after being released from high-temperature inhibition at 30 min before the start of DNA replication, no recovery replication was observed; whereas at 20 min, the recovery of replication was observed. These results indicated that HF4704S was temperature sensitive in the initiation of DNA replication. Analysis of HF4704S, by an interrupted conjugation experiment, indicated that gene
dnaH
was located at about 64 min on the
E. coli
C linkage map. In
E. coli
S1814 (a K-12 derivative), which was a
dnaH
ts
transductant from HF4704S (C strain) with phage P1, the mutated gene (
dnaH
) was demonstrated to be closely linked to the
thyA
marker by conjugation and P1 transduction experiments and to be distinct from genes
dnaA
through
dnaG
.
Protein Synthesis in
Bacillus subtilis
: Differential Effect of Potassium Ions on In Vitro Peptide Chain Initiation and Elongation
Authors: Sala F. , Bazzicalupo M. , Parisi B.
Published: January 2020

The preparation and fractionation of a highly active and stable in vitro protein-synthesizing system from
Bacillus subtilis
is described. Potassium satisfied the requirement for a monovalent ion when the initiation factor-dependent binding of formyl-methionyl-transfer ribonucleic acid and synthesis of formyl-methionyl-puromycin were assayed, whereas it inhibited the reactions for polyphenylalanine synthesis. On the other hand, the ammonium ion satisfied the requirement for all assayed reactions. The in vitro experimental evidence suggested that potassium is an inhibitor of one or a few specific reactions involved in peptide chain elongation in
B. subtilis
.
Surface Polysaccharide from
Staphylococcus aureus
M That Contains Taurine,
d
-Aminogalacturonic Acid, and
d
-Fucosamine
Authors: Liau Deng-Fong , Melly M. Ann , Hash John H.
Published: January 2020

The surface polysaccharide antigen of
Staphylococcus aureus
M was isolated, and the component parts were identified. The antigen is composed of taurine,
d
-aminogalacturonic acid, and
d
-fucosamine. The capsule is chemically distinct from all previously reported staphylococcal capsules. Taurine and aminogalacturonic acid have not been reported previously in staphylococci.
Bacterial Metabolism of
para
-and
meta
-Xylene: Oxidation of the Aromatic Ring
Authors: Gibson David T. , Mahadevan Venkatanarayana , Davey John F.
Published: January 2020

Pseudomonas putida
39/D oxidized
p
-xylene to
cis
-3,6-dimethyl-3,5-cyclohexadiene-1,2-diol (
cis-p
-xylene dihydrodiol). The latter compound was isolated in crystalline form and its physical properties were determined. The
cis
configuration of the hydroxyl groups in the oxidation product was inferred from its ability to form an isopropylidene derivative with 2,2-dimethoxypropane. Acid treatment of
cis-p
-xylene dihydrodiol resulted in the formation of 2,5-dimethylphenol. A partially purified preparation of
cis
-toluene dihydrodiol dehydrogenase oxidized
cis-p
-xylene dihydrodiol to 1,2-dihydroxy-3,6-dimethylbenzene (3,6-dimethylpyrocatechol).
P. putida
39/D oxidized
m
-xylene to a compound whose spectral and chromatographic characteristics were consistent with the structure 3,5-dimethyl-3,5-cyclohexadiene-1,2-diol. This product was very unstable, and all attempts to isolate it led to the formation of 2,4-dimethylphenol.
Pleiotropic Effects of Suppressor Mutations in
Bacillus subtilis
Authors: Tevethia M. J. , Baptist James N. , Mandel Manley
Published: January 2020

Isogenic strains of
Bacillus subtilis
carrying
sup-1
(26),
sup-3
(10), or their wild-type alleles were constructed in three genetic backgrounds. The patterns of suppression at 37 and 43.5 C, identity of mapping site, effects of the suppressor genes on growth rate, sporulation, and production of altered enzymes were examined. The similarity of the suppression pattern by
sup-1
and
sup-3
suggests that the suppressors are of the same type. They do not, however, represent mutations in the same gene, since, based on differences in temperature sensitivity of phage mutants in suppressor-containing hosts,
sup-1
and
sup-3
insert different amino acids and can coexist within the same cell. The ability to produce slow-migrating forms of enzymes of the type described in the accompanying paper was co-transferred with either of the suppressor genes during transformation, was lost on reversion of the suppressor mutations, and was independent of the genetic background. Similarly, transformation and reversion studies indicate that the additional pleiotropic properties such as slow growth rate and inability to attain competence or to yield plaques with φ105C4, which are characteristic of the Okubo
sup-1
strain (HA101B) but not its early sporulation defect, result from the presence of the suppressor mutation. The possible mechanisms by which altered enzyme forms and the additional pleiotropic effects are produced in suppressor strains are discussed. In addition, a newly recognized suppressor phenotype is described and partially characterized.
Isolation and Partial Characterization of a Temperature-Sensitive
Escherichia coli
Mutant with Altered Glutaminyl-Transfer Ribonucleic Acid Synthetase
Authors: Körner A. , Magee B. B. , Liska B. , Low K. B. , Adelberg E. A. , Söll D.
Published: January 2020

A temperature-sensitive mutant of
Escherichia coli
has been found in which the conditional growth is a result of a thermosensitive glutaminyl-transfer ribonucleic acid synthetase. The corresponding genetic locus
glnS
is cotransduced with
lip
. In a strain containing the mutationally altered glutaminyl-transfer ribonucleic acid synthetase, no derepression of the enzyme itself nor of glutamine synthetase was observed.
Active Transport of Choline by a Marine Pseudomonad
Authors: Snipes Wallace , Keith Alec , Wanda Paul
Published: January 2020

A marine pseudomonad, BAL-31, accumulates the phospholipid nitrogen base, choline, although no detectable amount of choline is incorporated into polar lipids. Metabolic inhibitors such as cyanide and azide block the uptake process as does starving for oxygen by using nitrogen gas. Only very close structural analogues show any inhibition of transport, indicating that the uptake process has great structural specificity. The export of choline out of the cells is also an energy-dependent process and is markedly reduced during oxygen depletion. The constitutive level of choline transport is increased by approximately a factor of three after a brief induction period. Two other gram-negative bacteria also accumulate choline, whereas a gram-positive bacterium,
Bacillus subtilis
, and a yeast,
Saccharomyces cerevisiae
, fail to show any detectable accumulation.
Mutants of the N-3 R-Factor Conditionally Defective in
hsp
II Modification and Deoxyribonucleic Acid-Cytosine Methylase Activity
Authors: Schlagman Samuel , Hattman Stanley
Published: January 2020

The N-3 drug resistance (R) factor specifies a deoxyribonucleic acid (DNA)-cytosine methylase and a DNA restriction-modification (
hsp
II) system. We have isolated three independent mutants that are conditionally defective in their ability to modify bacteriophage λ and to methylate DNA-cytosine residues. The ratio of 5-methylcytosine to N
6
-methyladenine in bacterial DNA and in the DNA of phages λ and fd was determined after labeling with [
methyl
-
3
H]methionine at various growth temperatures. Although the ability of the wild-type N-3 factor to modify phage λ and to methylate DNA-cytosine residues was unaffected with increasing temperature, two of the mutants exhibited a parallel loss in modification and cytosine methylation ability. The ability of the third mutant to carry out these functions was dependent on the presence or absence of an amber suppressor mutation in the host genome. These results offer further support for the notion that
hsp
II modification is mediated by a DNA-cytosine methylase. Evidence is also presented that the modification methylase is responsible for the in vivo methylation of phage fd DNA (which is not subject to
hsp
II restriction in vivo).
Inorganic and Metal-Organic Growth Requirements of the GenusBacteroides
Authors: Caldwell Daniel R. , Arcand Caryn
Published: January 2020

The inorganic and metal-organic growth requirements of ruminal and nonruminalBacteroidesspecies were compared. The heme requirement of many nonruminalBacteroidesspecies was similar to that ofBacteroides ruminicolasubsp.ruminicolaand was a general tetrapyrrole requirement. Some nonruminalBacteroidesspecies utilized succinate or alpha-ketoglutarate, as well as tetrapyrrole-containing compounds, in place of heme. Fe+as well as heme was required for maximal yields of someBacteroidesspecies. The divalent cation requirements ofBacteroidesspecies are complex. Mg2+deletion from a medium containing Mg2+, Ca2+, Co2+, and Mn2+reduced the yields of all isolates. Ca2+deletion from the same medium reduced the growth yields ofBacteroides fragilis, B. fundiliformis, and one strain ofB. oralis. The effects of Mg2+and Ca2+on the growth ofBacteroidesisolates was influenced by other divalent cations. Relatively large quantities of Na+were obligately required by all of the currently recognized predominant rumenBacteroidesspecies. NonruminalBacteroidesspecies either did not require Na+or required only small amounts. The Na+requirement of some nonruminalBacteroidesspecies could be partially replaced by Li+or Cs+. The Na+requirement of rumenBacteroidesspecies was absolute. The inorganic and metal-organic growth requirements ofBacteroidesspecies appear useful as aids in species differentiation.
Genetic Location of Two Mutations Affecting the Lysyl-Transfer Ribonucleic Acid Synthetase of
Bacillus subtilis
Authors: Racine Francis M. , Steinberg William
Published: January 2020

Two mutations (
lysS1
and
lysS2
), each independently resulting in a thermosensitive, lysyl-transfer RNA synthetase (
l
-lysine: tRNA ligase [adenosine 5′-monophosphate] EC 6.1.1.6), have been mapped on the
Bacillus subtilis
chromosome between
purA16
(adenine requirement) and
sul
(sulfanilamide resistance). They are linked by transformation with
sul
(70 to 74% cotransfer) in the order
purA16-lysS1-lysS2-sul
. The mutant loci are either in the same gene or in two closely linked genes. They are not linked to the tryptophanyl-tRNA synthetase structural gene or to the
lys-1
locus.
Loss of Photoreversibility of Damage to Deoxyribonucleic Acid Replication in Ultraviolet-Irradiated
Escherichia coli
B/r
thy trp
Authors: Doudney C. O.
Published: January 2020

Loss of photoreversibility (LOP) of the ultraviolet (UV) damage which prevents reinitiation of deoxyribonucleic acid (DNA) replication occurred with incubation of
Escherichia coli
B/r
thy trp
cultures after UV doses of 240, 320, and 400 ergs/mm
2
. LOP occurred at the time of reinitiation of DNA replication in the cultures (i.e., after postirradiation lag periods of 45 min or more). Neither the absence of thymine nor the absence of tryptophan prevented LOP of the damage to DNA replication, suggesting that neither DNA replication nor protein synthesis is necessary for the process. These findings suggest that attempted initiation of DNA replication results in transformation of pyrimidine damage into permanent damage to chromosome structure at the reinitiation site.
Metabolism of Benzoate and the Methylbenzoates by
Pseudomonas putida
(
arvilla
) mt-2: Evidence for the Existence of a TOL Plasmid
Authors: Williams Peter A. , Murray Keith
Published: January 2020

Mutant strains of
Pseudomonas putida
(
arvilla
) mt-2 which have lost the ability to grow at the expense of
m
- or
p
-toluate (methylbenzoate) but retain the ability to grow with benzoate arise spontaneously during growth on benzoate; this genetic loss occurs to a lesser extent during growth on nonaromatic carbon sources in the presence of mitomycin C. The mutants have totally lost the activity of the enzymes of the divergent
meta
pathway with the possible exception of 2-oxopent-4-enoate hydratase and 4-hydroxy-2-oxovalerate aldolase; unlike the wild type they utilize benzoate by the
ortho
pathway. Evidence is presented that these mutants have lost a plasmid coding for the enzymes of the
meta
pathway, which may be transmitted back to them or into other
P. putida
strains. Preliminary results from these mutants and from a mutant defective in the regulation of the plasmid-carried pathway suggest that the wild type contains two benzoate oxidase systems, one on the plasmid which is nonspecific in both its catalysis and its induction and one on the chromosome which is more specific to benzoate as substrate and is specifically induced by benzoate.
Selection Procedure for Mutants Defective in the β-Methylgalactoside Transport System of
Escherichia coli
Utilizing the Compound 2R-Glyceryl-β-
d
-Galactopyranoside
Authors: Silhavy Thomas J. , Boos Winfried
Published: January 2020

A procedure has been devised that allows selection of mutants defective in the β-methylgalactoside transport system (
mgl
) of
Escherichia coli
. This procedure utilizes the compound 2R-glyceryl-β-
d
-galactopyranoside (glycerylgalactoside), which is known to be transported by only two transport system in
E. coli
, namely, the lactose and the β-methylgalactoside transport systems. Mutants lacking glycerol-3-phosphate dehydrogenase (
glpD
) are sensitive to glycerol. Similarly, mutants lacking uridine diphosphate-galactose-4-epimerase (
galE
) are sensitive to galactose. Glycerylgalactoside is an inducer of the lactose operon and also a substrate for β-galactosidase. Thus, a
mgl
+
glpD galE lacY
strain will not grow in the presence of glycerylgalactoside owing to accumulated glycerol-3-phosphate, galactose-1-phosphate, and uridine diphosphate-galactose. We have constructed such a strain and shown that
mgl
mutants can be obtained by selecting for those that grow in the presence of glycerylgalactoside.
Use of Mucoid Bacterial Mutants to Circumvent Clumping of Cells and Minicells Containing R Plasmids Derepressed for Pilus Synthesis
Authors: Levy Stuart B.
Published: January 2020

Clumping of bacteria containing R factors derepressed for pilus synthesis interfered with the separation of cells and minicells. Mucoid derivatives of these bacteria provided the means of preventing clumping and allowing a good separation. This method may be generally useful in dealing with autoagglutination of bacterial cultures.
Use of Streptomycin and Cyclic Adenosine 5′-Monophosphate in the Isolation of Mutants Deficient in CAP Protein
Authors: Artman M. , Werthamer S.
Published: January 2020

A method is described for selective isolation of mutants deficient in CAP protein necessary for the expression of catabolite-sensitive operons in
Escherichia coli
.
Comparison of Butyric Type of Fermentation in Sporogenic and Asporogenic Mutants of
Clostridium botulinum
Authors: Emeruwa A. C. , Hawirko R. Z. , Halvorson Harvest , Suzuki I.
Published: January 2020

Glucose-adapted cells of a sporogenic mutant. MSp
+
, and an asporogenic mutant, RSpoIIIa, of
Clostridium botulinum
type E rapidly fermented glucose, fructose, maltose, and sucrose, resulting in cytoplasmic granulation, heavy growth, a pH of <6.0, and sporulation of the MSp
+
mutant ranging from 60 to 80%. In Trypticase peptone glucose broth, the MSp
+
mutant formed >80% refractile endospores in 25 h, whereas the RSpoIIIa mutant which was blocked at early forespore stage had commenced to lyse. Both mutants accumulated acetate and intracellular granules, reaching maximal levels at early stationary phase of growth. In MSp
+
, as the levels of acetokinase, phosphotransacetylase, and butyryl-coenzyme A dehydrogenase reached a maximum, butyrate accumulation continued concurrently with an increase of endospore formation, whereas the levels of poly-β-hydroxybutyrate decreased simultaneously with its precursor, acetate. Butyrate biosynthesis was blocked in the asporogenic mutant. As shown by isotopic assays, butyrate and acetate serve as precursors of spore lipids. β-Phenethyl alcohol, fluoroacetic acid, and 2-picolinic acid inhibited anaerobic sporogenesis almost completely, butyrate biosynthesis by >87%, and acetate accumulation by 50 to 62%, showing a direct relationship between butyric type of fermentation and anaerobic sporulation.
Isolation and Characterization of a Copy Mutant of the Bacteriocinogenic Plasmid Clo DF13
Authors: Kool A. J. , Nijkamp H. J. J.
Published: January 2020

After nitrosoguanidine mutagenesis, strain
Escherichia coli
P678-54, bacteriocinogenic for Clo DF13, yielded a mutant strain that showed an enhanced bacteriocin production. The results from conjugation experiments indicated that the mutation, responsible for the enhanced bacteriocin production, is located on the Clo DF13 plasmid. The following properties of strains harboring the mutant Clo DF13 plasmid could be observed. (i) The bacteriocin production in these strains can be further enhanced at least fourfold by mitomycin C. (ii) The fraction of spontaneously induced cells, as revealed by lacunae experiments, in cultures of these strains is about nine times higher than in cultures of wild-type Clo DF13-harboring strains. (iii) Chromosomeless minicells from strain P678-54 harboring the mutant Clo DF13 plasmid synthesize about six times more deoxyribonucleic acid, ribonucleic acid, and protein as compared to wild-type Clo DF13-harboring minicells. (iv) Analysis of this mutant Clo DF13-specific ribonucleic acid and protein on polyacrylamide gels revealed mainly the same ribonucleic acid and polypeptide species as synthesized by the wild-type Clo DF13 minicells, but in larger amounts (Kool et al., 1974). (v) Segregation experiments, using a strain with temperature-sensitive polymerase I, show that mutant Clo DF13-harboring cells contain an average of 70 Clo DF13 copies per cell, whereas wild-type Clo DF13-harboring cells contain only about 10 Clo DF13 copies per cell. The data presented in this paper indicate that the mutation on the Clo DF13 plasmid leads to an altered control of Clo DF13 replication and results in an enhanced number of Clo DF13 copies per cell. As a secondary effect, this enhanced number of Clo DF13 copies enhances the probability of “spontaneous” induction per cell. Since the mutation is plasmid specific and affects the number of plasmid copies produced, one can conclude that the Clo DF13 plasmid is not dependent solely on chromosomal information, but that at least plasmid base sequences are involved in Clo DF13 plasmid replication.
Glycerolphosphate-Containing Cell Wall Polysaccharides fromStreptococcus sanguis
Authors: Emdur L. I. , Saralkar C. , McHugh J. G. , Chiu T. H.
Published: January 2020

Six glycerolphosphate-containing tetraheteroglycans, a, b-1, b-2, b-3, b-4, and b-5, have been purified from the formamide extracts ofStreptococcus sanguisby alcohol and acetone precipitations, Sephadex G-75, and diethylaminoethyl-cellulose column chromatography. The polysaccharides were judged as at least 95% pure by analytical disc gel electrophoresis and immune double diffusion against rabbit antiserum. They were shown to be cell wall polysaccharides, since they formed a single band of identity in immune double diffusion with partially purified polysaccharide extracted from a purified cell wall preparation ofS. sanguis. The polysaccharides were composed ofl-rhamnose,d-glucose, andN-acetyld-glucosamine in a similar molar ratio, but varied in their glycerol and phosphate contents. They exhibited four different mobilities in polyacrylamide disc gel electrophoresis at pH 8.9. When they were treated with formamide at 170 C for 20 min, the faster moving polysaccharide(s) yielded polysaccharides with mobilities corresponding to the other slower moving polysaccharides. These results indicate that the polysaccharides originated from the same cell wall polysaccharide and were produced as a result of breakage in the phosphodiester bonds during the formamide extraction procedure. A preliminary structural study shows that the terminal reducing sugar isl-rhamnose and that the glycerol moiety is probably linked to the polysaccharide through a phosphodiester bond.
Thermal Death of Temperature-Sensitive Lysyl- and Tryptophanyl-Transfer Ribonucleic Acid Synthetase Mutants of
Bacillus subtilis
: Effect of Culture Medium and Developmental Stage
Authors: Steinberg William
Published: January 2020

The growth of thermosensitive
Bacillus subtilis
lysyl- and tryptophanyl-transfer ribonucleic acid synthetase mutants (
lysS1
and
trypS1
) (
l
-lysine:transfer ribonucleic acid [tRNA] ligase [AMP], EC 6.1.1.6; and
l
-tryptophan:tRNA ligase [AMP], EC 6.1.1.2) was terminated when exponential phase cells were shifted from 30 to 43 C in a rich medium. Under these conditions, the temperature-inhibited cells undergo thermal death; they rapidly lose their ability to form colonies at 30 C. Another lysyl-tRNA synthetase mutant (
lysS2
) is refractory to thermal death even though its growth is inhibited at 43 C. The thermal death response of the
lysS1
mutant is affected by the stage of cell development. At periods in spore outgrowth and sporogenesis these cells become refractory to thermal death. The refractory state does not result from the production of an inhibitor, or from the degradation of an activator of thermal death. However, culture medium composition does modify the thermal death response. Rich media enhance the effect, and no thermal death occurs in the
lysS1
strain grown in a minimal medium. Temperature-sensitive cells can grow in a lysine- (0.25 mM) or tryptophan- (0.25 mM) supplemented minimal medium at 43 C, but amino acid concentrations of 25 mM only transiently protect
trypS1
and
lysS1
cells from thermal death in a rich medium. Osmotic agents such as sucrose (0.5 M) and NaCl (0.34 M) completely prevent thermal death in the
lysS1
strain, although growth is still arrested. On solid media, sucrose stabilized
lysS1
cells can form colonies at the restrictive temperature, but neither sucrose (0.5 M) nor NaCl (0.34 M) stabilized the
lysS1
enzyme in vitro. Chloramiphenicol increased the rate of thermal death of the
lysS1
strain but decreased the thermal death response of the
trypS1
mutant. Considering the nature of the enzyme defect in the
lysS1
strain, the common genetic origin of the spore and vegetative lysyl-tRNA synthetase, and the protective effects exerted by lysine and osmotic agents, it is tentatively concluded that thermal death results from irreversible inactivation of the mutant gene product. According to this hypothesis, either the
lysS1
enzyme is altered during sporogenesis or some physiological or structural aspect of this developmental phase can stabilize the mutant phenotype and thereby rescue cells from thermal death.
Catabolite Repression and Derepression of Arylsulfatase Synthesis in
Klebsiella aerogenes
Authors: Adachi Toshiro , Okamura Haruki , Murooka Yoshikatsu , Harada Tokuya
Published: January 2020

When a mutant (Mao
−
) of
Klebsiella aerogenes
lacking an enzyme for tyramine degradation (monoamine oxidase) was grown with
d
-xylose as a carbon source, arylsulfatase was repressed by inorganic sulfate and repression was relieved by tyramine. When the cells were grown on glucose, tyramine failed to derepress the arylsulfatase synthesis. When grown with methionine as the sole sulfur source, the enzyme was synthesized irrespective of the carbon source used. Addition of cyclic adenosine monophosphate overcame the catabolite repression of synthesis of the derepressed enzyme caused by tyramine. Uptake of tyramine was not affected by the carbon source. We isolated a mutant strain in which derepression of arylsulfatase synthesis by tyramine occurred even in the presence of glucose and inorganic sulfate. This strain also produced β-galactosidase in the presence of an inducer and glucose. These results, and those on other mutant strains in which tyramine cannot derepress enzyme synthesis, strongly suggest that a protein factor regulated by catabolite repression is involved in the derepression of arylsulfatase synthesis by tyramine.
Isolation of atrans-Dominant Histidase-Negative Mutant ofSalmonella typhimurium
Authors: Hagen David C. , Lipton Peter J. , Magasanik Boris
Published: January 2020

A mutation ofSalmonella typhimuriumwas obtained that results in the failure of cells to synthesize the enzymel-histidine ammonia-lyase (histidase). The mutation mapped within thehutHgene and in merodiploid strains was dominant over the wild-type allele. Extracts from cells bearing thetrans-dominant histidase-negative allele were shown to contain material that reacts immunologically with antiserum against purified wild-type histidase. It is proposed that thetrans-dominant allele results in the synthesis of defective histidase subunits that can combine with, and partially inactivate, wild-type histidase subunits. This subunit mixing presumably does occur, as the enzyme synthesized in a hybrid merodiploid strain is abnormally heat sensitive.
Acid-Soluble Breakdown of Homologous Deoxyribonucleic Acid Adsorbed by
Haemophilus influenzae
: Its Biological Significance
Authors: Stuy Johan H.
Published: January 2020

Competent bacteria of
Haemophilus influenzae
strain Rd were exposed to various kinds of radioactive deoxyribonucleic acid (DNA) for short periods of time and at relatively low temperature. The fate of phage HP1 DNA was studied most extensively. Adsorbed DNA was partially acid solubilized by lysogens and by nonlysogens with very similar kinetics. The biological activity of the DNA decreased extensively in both lysogenic and nonlysogenic recipients. 2,4-Dinitrophenol had no effect on the acid solubilization but largely abolished the biological inactivation. Inactivation kinetics for three different markers and for the triple combination were roughly the same. The presence of 2,4-dinitrophenol in the medium, or the HP1 prophage in the chromosome, did not alter this observation. This suggests that acid solubilization involves the destruction of whole DNA molecules. In view of the absence of DNA homology between phage and host, it is concluded that acid-soluble breakdown of adsorbed transforming DNA is not an integral part of the donor DNA integration process. Behavior of mutant bacteria indicates that neither exonuclease III nor exonuclease V is involved.
Coenzyme M, Essential for Growth of a Rumen Strain of
Methanobacterium ruminantium
Authors: Taylor C. D. , McBride B. C. , Wolfe R. S. , Bryant M. P.
Published: January 2020

A growth factor present in rumen fluid and essential for growth of a rumen strain of
Methanobacterium ruminantium
was shown to be coenzyme M, 2-mercaptoethanesulfonic acid.
Internal Promoter P2 of the Histidine Operon of
Salmonella typhimurium
Authors: Ely Bert , Ciesla Zygmunt
Published: January 2020

The histidine operon internal promoter P2 allows initiation of transcription at a rate up to one-third that of the wild-type
his
operon.
Sporulation Properties of Cytochrome
a
-Deficient Mutants of
Bacillus subtilis
Authors: Taber H. , Freese E.
Published: January 2020

Three classes of cytochrome
a
-deficient mutants of
Bacillus subtilis
have been found to be asporogenic or oligosporogenic. All three classes showed declines in adenosine 5′-triphosphate (ATP) concentrations during early sporulation, at a time when ATP levels in wild-type strains are constant. Class III mutants were found to be deficient in aconitase and isocitric dehydrogenase, and showed reduced maximum growth in nutrient sporulation medium. These mutants also suffered the most rapid decline in ATP concentration in early sporulation, and exhibited neither the biphasic oxygen consumption curve nor the increase in pH normally observed at the end of logarithmic growth in nutrient sporulation medium. Nicotinamide adenine dinucleotide oxidase activities of purified membrane preparations were approximately normal for mutants in all classes, except for two of the class II mutants and one class III mutant. Neither cytochrome
a
nor cytochrome
c
appears to be an obligatory intermediate in cyanide-sensitive nicotinamide adenine dinucleotide oxidation in
B. subtilis
.
Regulation of Serine Transhydroxymethylase Activity in
Salmonella typhimurium
Authors: Stauffer George V. , Baker Carol A. , Brenchley Jean E.
Published: January 2020

The regulation of serine transhydroxymethylase (EC 2.1.2.1.;
l
-serine:tetrahydrofolic-5,10-hydroxymethyltransferase) has been investigated in
Salmonella typhimurium
LT2. Our results indicate that limitation of a methionine auxotroph for methionine does not cause derepression of this enzyme as reported for
Escherichia coli
. However, a sixfold decrease in specific activity was observed when
S. typhimurium
cells were grown in glucose minimal medium supplemented with serine, glycine, methionine, adenine, guanine, and thymine. None of these compounds added to the growth medium individually produced more than a 42% reduction of wild-type enzyme activity. This enhanced repression by the combination of compounds suggests a form of cumulative repression of this enzyme. Growth of serine and thymine auxotrophs, with the respective requirement of each limiting, did not result in increased enzyme activity. However, growth of a purine auxotroph with a limiting amount of either guanine or inosine resulted in a five- to sevenfold increase in enzyme activity. A second condition causing significant derepression (fourfold increase) above the levels observed with cells grown in minimal medium was the addition of 0.5 μg of trimethoprim per ml, an inhibitor of the dihydrofolate reductase activity. (A partial report on this work was presented at 1974 meeting of the American Society for Microbiology.)
Active Transport of
d
-Alanine and Related Amino Acids by Whole Cells of
Bacillus subtilis
Authors: Clark Virginia L. , Young Frank E.
Published: January 2020

Whole cells of
Bacillus subtilis
transported
d
-alanine and
l
-alanine by two different systems. The high-affinity system (

K
m

of 1 μM and

V
max

of 0.6 to 0.8 nmol/min per mg of protein) was specific for the two stereoisomers of alanine. The low-affinity system (

K
m

of 10 μM for
l
-alanine and 20 μM for
d
-alanine and glycine) had a

V
max

of 5 to 12 nmol/min per mg of protein. This system transported glycine,
d
-cycloserine, and
d
-serine, in addition to
d
- and
l
-alanine. Azide inhibited the uptake of these amino acids and caused the efflux of
d
-alanine from preloaded cells. These data suggest that transport of these amino acids is energized by the electron transport chain.
Transformation of
Bacillus subtilis
in α-Amylase Productivity by Deoxyribonucleic Acid from
B. subtilis
var.
amylosacchariticus
Authors: Yoneda Y. , Yamane K. , Yamaguchi K. , Nagata Y. , Maruo B.
Published: January 2020

Deoxyribonucleic acid (DNA) of
Bacillus subtilis
var.
amylosacchariticus
showed almost the same ability as
B. subtilis
Marburg to induce transfer of several genetic markers in DNA-mediated transformation. DNA-DNA hybridization data also showed an intimate relationship between the two strains. Genetic elements involved in the production of extracellular α-amylase (EC 3.2.1.1.) in
B. subtilis
var.
amylosacchariticus
were studied by using DNA-mediated transformation. Two Marburg derivatives, NA20(
amyR2
) and NA20-22(
amyR1
), produced about 50 and 10 U of α-amylase per mg of cells, respectively, whereas
B. subtilis
var.
amylosacchariticus
produced as much as 150 U of the enzyme per mg of cells. When
B. subtilis
var.
amylosacchariticus
was crossed with strain NA20-22 as recipient, transformants that acquired high α-amylase productivity (about 50 U/mg of cells) were obtained. Genetic analysis revealed that a regulator gene (
amyR
) for α-amylase synthesis was found in
B. subtilis
var.
amylosacchariticus
, as in the case of
B. natto
1212 (
amyR2
) and
B. subtilis
Marburg (
amyR1
). The allele was designated
amyR3;
it is phenotypically indistinguishable from
amyR2
, but is readily distinguishable from
amyR1
. The presence of
amyR3
was not sufficient for an organism to render production of an exceptional amount of α-amylase. Extra-high α-amylase producers could be obtained by crossing
B. subtilis
var.
amylosacchariticus
as donor with strain NA20 as recipient. The transformants produced the same or even greater amounts of the enzyme than the donor strain. Results suggest the presence of another gene that is involved in the production of the exceptional amount of α-amylase.
Rhythms of Enzyme Activity Associated with Circadian Conidiation in
Neurospora crassa
Authors: Hochberg Michael L. , Sargent Malcolm L.
Published: January 2020

The mycelial growth front of the band strain of
Neurospora
grown on a solid surface exhibits a circadian rhythm of conidiation. Enzyme assays on extracts from that mycelium have shown that the activities of 6 of 13 enzymes (nicotinamide adenine dinucleotide nucleosidase, isocitrate lyase, citrate synthase, glyceraldehydephosphate dehydrogenase, phosphogluconate dehydrogenase, and glucose-6-phosphate dehydrogenase) and soluble-protein content oscillate with the visible morphological change. The rhythmic enzymes associated with the Krebs and glyoxylate cycles are more active during conidiogenesis, whereas the activities of the rhythmic enzymes of glycolysis and the hexose monophosphate shunt are reduced during that phase. The absence of enzyme oscillations in wild-type and fluffy strains which do not form conidia under the conditions employed suggests that the enzyme fluctuations are associated with conidiogenesis itself. Oscillations of enzyme activity as a function of time are restricted to the growth front. A permanent record of rhythmicity associated with conidial and nonconidial regions does, however, exist in the mycelial mat behind the growth front. The activities of three enzymes (nicotinamide adenine dinucleotide nucleosidase, glucose-6-phosphate dehydrogenase, and phosphogluconate dehydrogenase) are not directly influenced by CO
2
concentration, but are correlated with the prescence or absence of conidiation which is controlled by CO
2
concentration. In contrast, citrate synthase and malate dehydrogenase activities are correlated with changes in CO
2
concentration.
Genetic and Biophysical Study of R Plasmids Conferring Sulfonamide Resistance in
Shigella
Strains Isolated in 1952 and 1956
Authors: Davey R. Brent , Pittard James
Published: January 2020

The conjugative plasmids determining sulfonamide resistance in five
Shigella
strains, each isolated from a different patient, have been characterized. One
S. flexneri
2a strain, isolated in 1952, harbored an fi
+
plasmid of molecular weight 53 × 10
6
, which specified synthesis of F-like pili and bore determinants for sulfonamide resistance (Su) and bacteriocinogeny (Col). This plasmid was compatible with plasmids of groups F
I
, F
II
, I
α
, and P. A second
S. flexneri
2a strain isolated in 1952 harbored an fi
−
plasmid of molecular weight 59 × 10
6
, bearing the Su determinant and compatible with all plasmids tested. This strain also harbored an fi
+
group-F
II
plasmid of molecular weight 42 × 10
6
, which bore the Col determinant and specified synthesis of F-like pili. Three
S. dysenteriae
2 strains isolated in 1956 carried apparently identical fi
−
plasmids of molecular weight 58 × 10
6
, which bore the Su determinant, could form transconjugants in
Pseudomonas
but not in
Proteus
, and were incompatible with the P-group plasmid RP4.
Deoxyribonucleic Acid-Directed In Vitro Synthesis of
ilv
-Specific Messenger Ribonucleic Acid by Extracts of
Escherichia coli
K-12
Authors: Smolin David E. , Umbarger H. E.
Published: January 2020

The synthesis of
ilv
-specific messenger ribonucleic acid (mRNA) by extracts of
Escherichia coli
K-12 has been demonstrated in a deoxyribonucleic acid (DNA)-dependent, coupled transcription-translation system.
ilv
-Specific mRNA was determined by hybridization either to double-stranded λ
c
I857
S
t68h80d
ilv
DNA (λh80d
ilv
DNA) immobilized on nitrocellulose filters or to its separate
l
and
r
strands in liquid. During conditions optimal for protein synthesis, slightly more than 6% of the total [
3
H]RNA synthesized by S-30 extracts of the threonine deaminase-negative strain CU5136 was
ilv
-specific. Of this RNA, nearly 30% was complementary to the
l
(correct) strand. Total
ilv
-specific mRNA synthesis in vitro was not affected by omission of valine or all 20 amino acids from the reaction mixture. Hybridization of
ilv
-specific mRNA made in vitro to the
l
strand of λh80d
ilv
DNA was effectively reduced in the presence of unlabeled RNA extracted from an
ilv
derepressed strain but not from an
ilv
deletion strain. In a purified transcription system, employing commercial RNA polymerase, twofold more
ilv
-specific mRNA was synthesized than in the coupled system, but this increase was entirely due to greater transcription of the
r
(incorrect) strand. An S-30 extract prepared from a strain isogenic to strain CU5136 but derepressed for
ilvA
gene expression synthesized twofold more
ilv
-specific mRNA in the coupled system. The significance of these findings is discussed.
Isolation of Membrane-Associated Folded Chromosomes from
Escherichia coli
: Effect of Protein Synthesis Inhibition
Authors: Ryder Oliver A. , Smith Douglas W.
Published: January 2020

The sedimentation properties of membrane-associated folded chromosomes prepared from
Escherichia coli
TAU-bar at 0 to 4 C were studied. Utilizing a modification of the procedure of Stonington and Pettijohn (1971), quantitative yields of membrane-associated folded chromosomes may be obtained. Folded chromosomes remained associated with the cell envelope during their replication and after completion of residual synthesis in the absence of required amino acids, as demonstrated by sedimentation velocities and the presence of high levels of cosedimenting protein. Membrane-associated folded chromosomes isolated from amino acid-starved cells sedimented more rapidly than membrane-associated folded chromosomes isolated from exponentially growing cells.
R Factor Proteins Synthesized in
Escherichia coli
Minicells: Incorporation Studies with Different R Factors and Detection of Deoxyribonucleic Acid-Binding Proteins
Authors: Levy Stuart B.
Published: January 2020

Analysis of the protein synthesized by
Escherichia coli
minicells containing R factors demonstrated a variety of low- and high-molecular-weight polypeptides in sodium dodecyl sulfate (SDS)-polyacrylamide gels. Only half of this protein was released into a soluble fraction on lysis of these minicells. The other half remained associated with the minicell envelope. The efficiency of precursor incorporation into protein and the kinds of proteins synthesized changed with the age of the minicells at the time of harvest. About 1 to 2% of the soluble R factor-coded protein bound to calf thymus,
E. coli
, or R factor DNA-cellulose. Although most of these proteins were excluded from Sephadex G-100 columns, they migrated chiefly as low-molecular-weight-polypeptides (13,000 to 15,000) in SDS-polyacrylamide gels. Additional DNA-binding proteins that appeared to be higher-molecular-weight peptides were noted in extracts from younger minicells. At least one protein, identified as an SDS band, appeared to bind selectively to R factor DNA-cellulose. Minicells with R factors also contained DNA-binding proteins of cell origin, including the core RNA polymerase. No such binding proteins were found in R
−
minicells. These studies suggest that: (i) R factors code for proteins that may be involved in their own DNA metabolism; (ii) R factor DNA-binding proteins may be associated with larger host cell DNA-binding proteins or subunits of larger R factor proteins; and (iii) the age of the minicell influences the extent of protein synthesis and the kinds of proteins synthesized by R factors in minicells.
Characteristics of a Bacillus subtilis W23 mutant temperature sensitive for initiation of chromosome replication
Authors: Upcroft P , Dyson H J , Wake R G
Published: January 2020

A temperature-sensitive mutant of Bacillus subtilis W23, dna-20 (Ts), has been isolated and shown to be defective in initiation of rounds of chromosome replication at the nonpermissive temperature. Upon transfer of dna-20(Ts) from 30 to 45 C, deoxyribonucleic acid synthesis, as measured by [3H]thymine incorporation, gradually ceases. The distribution of genetic markers among unreplicated and replicated deoxyribonucleic acid, isolated from dna-20(Ts) after a period at 43 C in a medium containing 5-bromouracil, and fractionated in a CsCl gradient, shows that the cessation of initiation at the higher temperature is immediate. On the other hand, ribonucleic acid and protein synthesis continues at elevated or unaltered rates for some time after the shift to 45 C. Marker frequency analysis shows that all rounds of replication in progress at the time of the temperature shift terminate rapidly (within 40 min), even when chromosomes are replicating dichotomously in rich media. dna-20(Ts) remains 100% viable for at least 2 h at 45 C. Over a 5-h period at 45 C the nuclear bodies remain compact; a small number (less than 5%) of deoxyribonucleic acid-less cells are produced, but there is no morphological distortion of the cells. When the cells are returned to 30 C after 2 h at 45 C, chromosome replication is initiated rapidly at the normal origin and then proceeds in the normal established sequence. However, a second round of replication is initiated soon after the first. dna-20(Ts) has been shown to map as a B-group mutation, the major class of initiation mutants identified in B. subtillus 168.
Sensitivity of a Bacteroides melaninogenicus strain to monosaccharides: effect on enzyme induction
Authors: Lev M , Milford A F
Published: January 2020

The inhibition of growth in Bacteroides melaninogenicus by sugars in described. Monosaccharides such as D-glucose, D-galactose, D-mannose, and D-fructose are inhibitory at low concentrations, whereas the disaccharides sucrose and lactose are not inhibitory even at high concentrations. The major inhibitory effect of the sugar is found during the transition of lag to logarithmic growth phases. There was no primary effect of D-glucose on protein, ribonucleic acid, or deoxyribonucleic acid synthesis on cells in transition from lag to logarithmic growth. However, the addition of glucose or galactose completely abolished the induction of 3-ketodihydrosphingosine synthetase by vitamin K in vitamin K-depleted cells. Futhermore, in cells which were not vitamin K depleted, the level of this enzyme was drastically reduced by the addition of the sugar. Cyclic adenosine 5-monophosphate was unable to reverse the growth inhibition produced by glucose. In actively growing cultures, addition of sugar slows the growth rate. In these experiments the level of 3-ketodihydrosphingosine synthetase fell only after the cells had assumed the slower rate of growth. There were two indications that D-galactose was more inhibitory than D-glucose; in the presence of 0.1% D-galactose cells in lag phase did not show the increase in turbidity found in similar cells placed in medium with 0.1% D-glucose, and also D-galactose caused a greater decrease in the growth rate of actively growing cultures than was found with D-glucose. These studies suggest that the inhibitory effect of monosaccharides in lag leads to logarithmic growth transition can be ascribed to an effect on enzyme induction. On the other hand, the ability of many monosaccharides to inhibit growth, and the greater inhibitory property of D-galactose compared with D-glucose, suggests that other mechanisms may be operative as well.