bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth of the
Bacillus subtilis
Cell Surface
Authors: Reeve John N.
Published: January 2020

A double mutant strain,
Bacillus subtilis div IV B1 dal trp
, has been constructed which grows as filamentous cells and minicells and requires
d
-alanine for growth. Removal of
d
-alanine from a growing population of cells resulted in cell bulging 25% of the cell length from one cell pole, followed by cell lysis. Little ultrastructural change in the cell envelope could be detected during bulge formation.
Membrane Adenosine Triphosphatase ofMicrococcus lysodeikticus: Effect of Millimolar Mg2+in Modulating the Properties of the Membrane-Bound Enzyme
Authors: Lastras Mercedes , Muñoz Emilio
Published: January 2020

The latency ofMicrococcus lysodeikticusmembrane-bound Mg2+-adenosine triphosphatase (ATPase) is expressed by the ratio of its activity assayed in the presence of trypsin (“total”) versus the activity assayed in absence of the protease (“basal”). By isolating membranes in the presence of variable concentrations of Mg2+(50 mM, 10 mM, or none) and by washing them with different Mg2+- and ethylenediaminetetraacetic acid-containing tris(hydroxymethyl)aminomethane-hydrochloride buffers (pH 7.5), we showed that the enzyme latency was dependent on the environmental concentration of this divalent metal ion. Mg2+bound to at least two classes of sites. The binding of Mg2+to low-affinity sites (saturation at approximately 40 mM external Mg2+) induced a high basal ATPase activity, whereas its binding to medium-affinity sites (saturation at about 2 mM Mg2+) correlated with low basal activity and a very high stimulation by trypsin. Membranes with tightly bound Mg2+(high affinity?) revealed an intermediate behavior for the latency ofM. lysodeikticusATPase. The Mg2+/Ca2+antagonism as activators of the membrane ATPase was not directly related to Mg2+binding by the membranes. The efficiency of the ATPase release fromM. lysodeikticusmembrane by 3 mM tris(hydroxymethyl)aminomethane-hydrochloride buffer (pH 7.5) was inversely proportional to the concentration of external and/or bound Mg2+. Deoxycholate (DOC) (1%) solubilized the ATPase from all types of membrane. All the soluble ATPases behaved as Ca2+-ATPases, but the DOC-soluble fractions showed degrees of latency like those of the original membranes. The DOC-soluble ATPase preparation revealed a vesicular structure and complex protein patterns by sodium dodecyl sulfate gel electrophoresis. We propose that ATPase latency is modulated via a Mg2+-ATPase-membrane complex.
Superficial Macromolecular Arrays on the Cell Wall of
Spirillum putridiconchylium
Authors: Beveridge T. J. , Murray R. G. E.
Published: January 2020

Electron microscopy of the cell envelope of
Spirillum putridiconchylium
, using negatively stained, thin-sectioned, and replicated freeze-etched preparations, showed two superficial wall layers forming a complex macromolecular pattern on the external surface. The outer structured layer was a linear array of particles overlying an inner tetragonal array of larger subunits. They were associated in a very regular fashion, and the complex was bonded to the outer, pitted surface of the lipopolysaccharide tripartite layer of the cell wall. The relationship of the components of the two structured layers was resolved with the aid of optical diffraction, combined with image filtering and reconstruction and linear and rotary integration techniques. The outer structural layer consisted of spherical 1.5-nm units set in double lines determined by the size and arrangement of 6- by 3-nm inner structural layer subunits, which bore one outer structural layer unit on each outer corner. The total effect of this arrangement was a double-ridged linear structure that was evident in surface replicas and negatively stained fragments of the whole wall. The packing of these units was not square but skewed by 2° off the perpendicular so that the “unit array” described by optical diffraction and linear integration appeared to be a deformed tetragon. The verity of the model was checked by using a photographically reduced image to produce an optical diffraction pattern for comparison with that of the actual layers. The correspondence was nearly perfect.
Autolysis in
Staphylococcus aureus
: Preferential Release of Old Cell Walls
Authors: Gilpin R. W. , Narrod S. , Wong W. , Young F. E. , Chatterjee A. N.
Published: January 2020

The kinetics of release of old versus new cell wall in two strains of
Staphylococcus aureus
were studied during autolysis. In both strains the autolytic enzyme is an amidase. Cells were double labeled with
3
H and
14
C, and the distribution of radioactivity in the cell walls was monitored during autolysis. In all cases the rate of release of steady-state lable from peptidoglycan was significantly higher than that of pulse label. Identical results were obtained with whole cells or isolated cell walls. The results suggest that in
S. aureus
the old cell wall is preferentially released during autolysis.
Mutational Analysis of Dark Endogenous Metabolism in the Blue-Green Bacterium
Anacystis nidulans
Authors: Doolittle W. Ford , Singer Richard A.
Published: January 2020

We describe a mutant (strain 704) of the obligate photoautotroph
Anacystis nidulans
which behaves like the wild type under continuous illumination but which in the dark rapidly loses viability, respires little, and incorporates label into ribonucleic acid and protein at rates considerably less than observed with the darkened wild type. Extracts of this mutant strain show no detectable 6-phosphogluconate dehydrogenase (EC 1.1.1.44) activity. Spontaneous revertants of mutant 704 were selected as survivors of prolonged incubation in darkness. Of 10 such strains examined, none had regained 6-phosphogluconate dehydrogenase activity, and all had lost detectable glucose-6-phosphate dehydrogenase (EC 1.1.1.49) activity. Although dark survival of these revertants paralleled that of the wild type, rates of dark endogenous respiration and incorporation of labeled precursors into ribonucleic acid were still very low, comparable to those observed with strain 704. These results are consistent with the following hypotheses concerning dark endogenous metabolism in unicellular blue-green bacteria. (i) Although the oxidative pentose phosphate cycle (hexose monophosphate shunt) may play a major role in endogenous metabolism in
A. nidulans
, as proposed by others, it is not the only pathway capable of providing energy for maintenance of viability in darkness. (ii) Much of the endogenous metabolic activity (respiration and macromolecular synthesis) observed in darkened cultures of wild-type
A. nidulans
is not required for survival alone, and must therefore serve other functions.
Linkage Analysis inDictyostelium discoideumUsing Temperature-Sensitive Growth Mutants Selected with Bromodeoxyuridine
Authors: Kessin Richard H. , Williams Keith L. , Newell Peter C.
Published: January 2020

Amoebae of the cellular slime moldDictyostelium discoideumgrown in the presence of bromodeoxyuridine are killed on exposure to near-ultraviolet light. By using this phenomenon, a method was devised by which mutants ofD. discoideumthat are temperature-sensitive for growth can be readily obtained. Three such mutants have been characterized genetically and each was found to be associated with a different linkage group. Two of these linkage groups have not previously been described.
Hydrocarbon Metabolism by
Brevibacterium erythrogenes
: Normal and Branched Alkanes
Authors: Pirnik M. P. , Atlas R. M. , Bartha R.
Published: January 2020

Branched- and straight-chain alkanes are metabolized by
Brevibacterium erythrogenes
by means of two distinct pathways. Normal alkanes (e.g.,
n
-pentadecane) are degraded, after terminal oxidation, by the beta-oxidation system operational in fatty acid catabolism. Branched alkanes like pristane (2,6,10,14-tetramethylpentadecane) and 2-methylundecane are degraded as dicarboxylic acids, which also undergo beta-oxidation. Pristane-derived intermediates are observed to accumulate, with time, as a series of dicarboxylic acids. This dicarboxylic acid pathway is not observed in the presence of normal alkanes. Release of
14
CO
2
from [1-
14
C]pristane is delayed, or entirely inhibited, in the presence of
n
-hexadecane, whereas CO
2
release from
n
-hexadecane remains unaffected. These results suggest an inducible dicarboxylic acid pathway for degradation of branched-chain alkanes.
Temperature-Sensitive Modification and Restriction Phenotypes of an
Escherichia coli dnaD
Mutant
Authors: Paul Aniko V. , Inouye Masayori
Published: January 2020

A mutant of
Escherichia coli
temperature-sensitive for deoxyribonucleic acid synthesis,
dnaD
, was found to have temperature-sensitive modification and restriction phenotypes. In contrast to the original observation by Carl (1970), the mutant could support the growth of λ phage at 41 C. However, the λ phages thus produced were able to form plaques with normal plating efficiency only on
E. coli
C, a restriction-less strain, but not on
E. coli
K. Since the λ phages produced in the mutant at 30 C could form plaques equally well on both
E. coli
strains, it was concluded that the
dnaD
mutant has a temperature-sensitive modification phenotype. Furthermore, since the
dnaD
mutant allowed some growth of unmodified λ·C phages at 41 C but less at 30 C, the mutant is also temperature sensitive in restriction. The relationship, if any, between temperature-sensitive deoxyribonucleic acid synthesis and temperature-sensitive modification-restriction in the
dnaD
mutant is not known. Similar experiments were done with three
dnaC
mutants and one
dnaA
mutant. Two
dnaC
mutants were found to have altered restriction phenotypes at 41 C, but none of the mutants were defective in modification.
Genetic Transformation of Biosynthetically Defective
Neisseria gonorrhoeae
Clinical Isolates
Authors: Catlin B. Wesley
Published: January 2020

Deoxyribonucleic acid (DNA) and chemically defined media were used in transformation tests of 51 strains of
Neisseria gonorrhoeae
which exhibited various biosynthetic defects when isolated from patients. These auxotrophic gonococci had one or more nutritional requirements involving proline, methionine, arginine, hypoxanthine, uracil, and thiamine pyrophosphate (THPP). DNA from a clinical isolate which did not require these compounds for growth on defined medium transformed each of the auxotrophic markers of all 51 recipient populations. Ten isolates had defects involving the synthesis of THPP; four strains (designated Thp
−
) had a growth requirement that was satisfied only by THPP, whereas the requirement of six strains (designated Thi
−
) was satisfied by either thiamine or THPP. DNA from Thp
−
donors elicited transformation of Thp
−
as well as Thi
−
recipients. Reciprocally, DNA from a Thi
−
donor transformed both Thi
−
and Thp
−
recipients. Furthermore, DNA from other auxotrophic gonococci had transforming activity for some phenotypically similar auxotrophic recipients. The findings indicate the existence of various nonidentical genetic defects which block reactions in the biosynthesis of proline, methionine, arginine, hypoxanthine, and THPP. Routine cultures from patients with gonorrhea were the source of these auxotrophic strains of
N. gonorrhoeae
; the various nutritional requirements were identified by a recently described system of gonococcal auxotyping. The transformation test results verify the hereditary basis of the auxotypes, establish that many different mutations exist in potentially virulent gonococci, and illustrate the value of these auxotrophic mutants for studies of the genetic structure and evolution of natural populations of gonococci.
Lactose Permeation Via the Arabinose Transport System in
Escherichia coli
K-12
Authors: Messer Anne
Published: January 2020

This paper describes the isolation and characterization of a mutant of
Escherichia coli
that transports lactose and its analog thiomethylgalactoside via the arabinose permeation system. Unlike transport via the lactose permease, this transport is not inhibited by thiodigalactoside, but was inhibited by arabinose, xylose, and fucose. The site of the mutation was in the arabinose
C
gene and confers constitutivity on the entire arabinose operon. Furthermore, this transport was found in 24 independently isolated arabinose-constitutive strains, and in strains which had been induced with arabinose and then starved to remove all traces of it. It was therefore concluded that lactose and thiomethylgalactoside are low-affinity substrates of at least one component of the normal arabinose permeation system.
β-Galactosidase from Termination and Deletion Mutant Strains
Authors: Villarejo Merna R. , Zabin Irving
Published: January 2020

β-Galactosidase fragments were isolated from strains of
Escherichia coli
with mutations in the
lacZ
gene. The polypeptide obtained from a termination mutant (
lacZNG125
) appeared to be the intact gene product, containing the first half of the β-galactosidase amino acid sequence. From an internal deletion mutant strain (
lacZU163
), an aggregate was obtained of several partially degraded polypeptides. Each of these was smaller than predicted from genetic data for the fragment. Introduction of the
lacZU163
mutation into a protein degradation-deficient strain (Deg
−
) resulted in the protection of the amino-terminal region of the protein. Some of the BrCN peptides from the U163 polypeptides were separated and identified. From such experiments it was shown that in both Deg
−
and Deg
+
strains the COOH-terminal region is rapidly degraded. This indicates that the complete gene product of
lacZU163
has not been detected. The use of genetically defined enzyme fragments in studying structure-function relationships and in determination of primary structure is discussed.
Mutant of
Escherichia coli
K-12 Missing Acetolactate Synthase Activity
Authors: Guardiola John , Felice Maurilio De , Iaccarino Maurizio
Published: January 2020

A mutant requiring isoleucine and valine for growth, because of the absence of acetolactate synthase activity, has been isolated. At least one of three different genes (
ilvG, ilvB, ilvI
) is required for the expression of acetolactate synthase activity, thus suggesting the presence of three different acetolactate synthase isoenzymes.
l
-Ribulokinase from an Initiator Constitutive Mutant
Authors: Gielow William O. , Lee Nancy L.
Published: January 2020

The N-terminal sequence of
l
-ribulokinase (EC 2.7.1.16) isolated from an initiator constitutive (
araI
−
) mutant is identical to wild-type kinase, indicating that the I
c
mutation probably lies outside of kinase structural gene
araB
.
Nicotinamide Adenine Dinucleotide Phosphate-Dependent Formate Dehydrogenase from
Clostridium thermoaceticum:
Purification and Properties
Authors: Andreesen Jan R. , Ljungdahl Lars G.
Published: January 2020

The nicotinamide adenine dinucleotide phosphate (NADP)-dependent formate dehydrogenase in
Clostridium thermoaceticum
used, in addition to its natural electron acceptor, methyl and benzyl viologen. The enzyme was purified to a specific activity of 34 (micromoles per minute per milligram of protein) with NADP as electron acceptor. Disc gel electrophoresis of the purified enzyme yielded two major and two minor protein bands, and during centrifugation in sucrose gradients two components of apparent molecular weights of 270,000 and 320,000 were obtained, both having formate dehydrogenase activity. The enzyme preparation catalyzed the reduction of riboflavine 5′-phosphate flavine adenine dinucleotide and methyl viologen by using reduced NADP as a source of electrons. It also had reduced NADP oxidase activity. The enzyme was strongly inhibited by cyanide and ethylenediaminetetraacetic acid. It was also inhibited by hypophosphite, an inhibition that was reversed by formate. Sulfite inhibited the activity with NADP but not with methyl viologen as acceptor. The apparent

K
m

at 55 C and pH 7.5 for formate was 2.27 × 10
−4
M with NADP and 0.83 × 10
−4
with methyl viologen as acceptor. The apparent

K
m

for NADP was 1.09 × 10
−4
M and for methyl viologen was 2.35 × 10
−3
M. NADP showed substrate inhibition at 5 × 10
−3
M and higher concentrations. With NADP as electron acceptor, the enzyme had a broad pH optimum between 7 and 9.5. The apparent temperature optimum was 85 C. In the absence of substrates, the enzyme was stable at 70 C but was rapidly inactivated at temperatures above 73 C. The enzyme was very sensitive to oxygen but was stabilized by thiol-iron complexes and formate.
Unidirectional Growth and Branch Formation of a Morphological Mutant,
Agrobacterium tumefaciens
Authors: Fujiwara Tamio , Fukui Sakuzo
Published: January 2020

Morphological characteristics of thermoconditional mutant
Agrobacterium tumefaciens
F-502 were investigated in relation to growth, division, and synthesis of cellular components. As a result of a shift from 27 to 37 C, mutant cells altered their morphology from short rods to elongated and branched forms; in addition, division and deoxyribonucleic acid synthesis were inhibited at 37 C. At 37 C unidirectional cell growth and branch formation occurred at one end of a cell, and the elongation rate of a cell was proportional to cell length. A hypothetical model for branch formation is presented in which the maximal elongation rate, 1.8 μm/h, at one end of a cell is an essential factor for initiation of branch formation.
Characterization of a Dominant, Constitutive Mutation,
PHOO
, for the Repressible Acid Phosphatase Synthesis in
Saccharomyces cerevisiae
Authors: Toh-E Akio , Oshima Yasuji
Published: January 2020

An apparent operator-constitutive mutation was discovered in the repressible acid phosphatase system in
Saccharomyces cerevisiae
. The site of mutation, designated
PHOO
, was found to be closely linked to the
phoD
locus. The mutant allele,
PHOO
, was semidominant over the wild-type allele and effective for the expression of the
phoD
gene in
cis
position. The
phoD
mutation gave rise to a defective phenotype for the formation of the repressible acid phosphatase. On the other hand, neither the repressible acid phosphatase activity in the cell-free extracts prepared from cells of the temperature-sensitive
phoD
mutant grown at 25 C, nor that of the revertants from the
phoD
mutants, could be distinguished from that of the wild-type strain with respect to thermolability and

K
m

value for
p
-nitrophenylphosphate. These results strongly suggest that the
phoD
gene is not a structural gene, but a regulatory gene exerting positive control for the formation of repressible acid phosphatase. Close similarity between the apparent role of the
phoO-PHOD
gene cluster and that of the
c-GAL4
gene cluster in the galactose system of
S. cerevisiae
could be inferred.
Transduction and Plasmid Deoxyribonucleic Acid Analysis in a Multiply Antibiotic-Resistant Strain of
Staphylococcus epidermidis
Authors: Rosendorf Linda L. , Kayser Fritz H.
Published: January 2020

A genetic analysis of a multiply antibiotic-resistant strain of
Staphylococcus epidermidis
was performed. Experiments designed to show reversion of organisms to antibiotic susceptibility, as well as studies of the influence of ultraviolet irradiation of phage on the transduction frequencies of the resistance markers, indicated that determinants of chloramphenicol (
cml
), tetracycline (
tet
), and neomycin (
neo
) resistance are present on separate plasmids, but the streptomycin marker is chromosomal. In 2 to 6% of tetracycline-resistant transductants, co-transduction of
cml
was also observed. By using CsCl-dye density gradients followed by neutral sucrose gradients, the plasmids carrying
cml, tet
, and
neo
could be isolated and their molecular weights could be determined. The tetracycline plasmid is shown to be incompatible with one of the cryptic plasmids of a recipient strain.
5-Bromouridylyl-(3′ → 5′)-Adenosine Isolated from 5-Bromouracil-Induced Filaments of
Escherichia coli
Authors: Jones Roosevelt J. , Thompson Dorothy P.
Published: January 2020

A dinucleoside monophosphate was isolated from 5-bromouracil-induced filaments of a thymine auxotroph of
Escherichia coli
K-12. The dinucleoside monophosphate was fractioned from a [
14
C]5-bromouracil-labeled perchloric acid extract using Dowex-1-formate ion-exchange chromatography. Sephadex chromatography revealed its molecular weight to be 710. Snake venom phosphodiesterase digest of the dinucleoside monophosphate yielded [
14
C]5-bromouridine and adenosine 5′-monophosphate. The presence of [
14
C]5-bromouracil in bacterial ribonucleic acid indicates that ribonucleic acid, which had incorporated 5-bromouracil, was the probable source of this dinucleoside monophosphate, 5-bromouridylyl-(3′ → 5′)-adenosine.
Incompatibility in
Podospora anserina
: Comparative Properties of the Antagonistic Cytoplasmic Factors of a Nonallelic System
Authors: Labarère Jacques , Bégueret Joël , Bernet Jean
Published: January 2020

In the fungus
Podospora anserina
, the interaction between the nonallelic incompatible
R
and
V
genes has two consequences: a lytic reaction due to the synthesis of specific proteolytic enzymes, and a quenching in protein and ribonucleic acid synthesis. The incompatibility reaction when vegetative or sexual
R
and
V
cells fuse is asymmetric: it is induced only in the
R
protoplasm. The cessation in ribonucleic acid and protein synthesis was investigated in heterokaryotic strains carrying the antagonistic
R
and
V
genes and their “neutral”
r
and
v
alleles. Asymmetry between
R
and
V
genes lies in the fact that the strains homozygous for the
R
genes are the only strains that cannot grow. From these results it is postulated that the
V
-gene product is a diffusible cytoplasmic factor and that the
R
-gene product, which is nonautonomous, is a ribosomal component.
Round-Cell Mutant of
Salmonella typhimurium
Authors: Wyche James H. , Kennedy Janet , Hartman Zlata , Hartman Philip E. , Diven James
Published: January 2020

A mutation at the
divD
locus in
Salmonella typhimurium
confers a round-cell morphology and enhances cell division under certain growth conditions.
Cellular Location of Degradative Enzymes in
Staphylococcus aureus
Authors: Nugent K. M. , Huff E. , Cole R. M. , Theodore T. S.
Published: January 2020

Staphylococus aureus
, ATCC 6538P, was fractionated into protoplast membranes, mesosomal vesicles, periplasm, and cytoplasm. These fractions and the culture fluid were then assayed for various degradative enzyme activities. They were not restricted to a single fraction nor dispersed homogeneously, but were distributed predominantly (on the basis of specific activity) as follows: nuclease in the culture fluid; alkaline phosphatase, 5′-nucleotidase, and acid phosphatase in the periplasm; adenosine triphosphatase in the protoplast membrane; and protease (low levels) in mesosomal vesicles. No significant esterase nor cell wall hydrolytic activity was found in any fraction.
S. aureus
80/81 was studied for penicillinase activity after induction with benzyl penicillin; this enzyme was localized in the mesosomal vesicles. Electron microscopy did not reveal any ultrastructural changes associated with secretion of the extracellular fraction. Overall, these studies demonstrate that degradative enzymes are located in several surface compartments and that, therefore, the mesosome does not function as a prototype lysosome in
S. aureus
.
Regulation of the Pool Size of Valine in
Escherichia coli
K-12
Authors: Felice Maurilio De , Guardiola John , Malorni Maria C. , Klopotowski Tadeusz , Iaccarino Maurizio
Published: January 2020

Three mutations (
ilvH611, ilvH612
, and
ilvH613
) are described which make
Escherichia coli
K-12 resistant to valine inhibition and are located near
leu
. The expression of the
ilv
genes appears to be normal in these mutants since the isoleucine-valine biosynthetic enzymes are not derepressed relative to the wild type. The intracellular concentration of valine is, however, higher in the mutants than in the isogenic
ilvH
+
strain. These mutants also excrete valine, probably because of the high intracellular concentration of this amino acid. The pool size of valine is regulated independently from that of isoleucine and leucine. The increased intracellular concentration of valine is due to a decreased feedback inhibition that valine exerts on its own biosynthetic pathway. In fact, acetolactate synthase activity assayed in extracts of
ilvH612
and
ilvH613
mutants is more resistant to valine inhibition than the activity assayed in the
ilvH
+
isogenic strain. Two forms of acetolactate synthase activity can be separated from these extracts by adsorption and elution on hydroxylapatite. One of them is as sensitive to valine inhibition as that of the wild type, the other is more resistant to valine inhibition.
Properties of Two Homologous Alkaline Proteases from
Streptomyces rectus
Authors: Borgia Peter , Campbell L. Leon
Published: January 2020

Some physicochemical properties of two thermostable proteases from
Streptomyces rectus
are described. The enzymes were judged to be identical with respect to molecular weight, inactivation with serine protease inhibitors, and in primary structure by peptide analysis. Amino acid analysis indicated the enzymes had identical compositions except for their amide content. The molecular weights of the enzymes were judged to be 28,000 by sedimentation equilibrium, 26,200 by sedimentation diffusion, and 29,100 from amino acid analysis. Titration of the proteases with diisopropylfluorophosphate and phenylmethane sulfonylfuoride indicate equivalent weights of 28,500 and 32,800 g, respectively, for the proteins. The pentapeptide around the serine residue reacting with diisopropylfluorophosphate was isolated and had the composition: Asx
1
, Gly
1
, Thr
1
, Ser
1
, Met
1
.
Purification and Characterization of the Nocardial Acetylesterase Involved in 2-Butanone Degradation
Authors: Eubanks Elizabeth F. , Forney F. W. , Larson A. D.
Published: January 2020

An inducible acetylesterase (EC 3.1.1.6) that hydrolyzes ethyl acetate, an intermediate in the degradation of 2-butanone by
Nocardia
strain LSU-169, was purified. The polypeptide molecular weight as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was 39,500, and the enzyme molecular weight determined by sucrose density gradient centrifugation was 84,000. The purified enzyme demonstrated aggregation in polyacrylamide gels. The esterase hydrolyzed
p
-nitrophenyl acetate, ethyl acetate, and methyl acetate; however, enzymatic hydrolysis of phosphates, sulfates, dipeptides, lactones, or the ethyl esters of
N
-benzoyl-
l
-tyrosine could not be detected. The apparent

K
m

for esterase activity with
p
-nitrophenyl acetate as the substrate was 6.7 × 10
−5
M, and the maximal velocity (
V
) was 1,223 μmol/min per mg of protein at 30 C. With ethyl acetate as the substrate, the apparent

K
m

was 3.6 × 10
−4
M and
V
was 1,026 μmol/min per mg of protein. No significant inhibition of esterase activity was obtained with organophosphates, mercuric compounds, eserine sulfate, sodium arsanilate, NaF, CaCl
2
, CoCl
2
, or MnCl
2
. At concentrations from 7 × 10
−4
to 4 × 10
−3
M, 2-butanol and primary alcohols with chain lengths of four or more carbons inhibited esterase activity from 59 to 86%. Linear noncompetitive inhibition of esterase activity by 3-methyl-1-butanol with a

K
i

of 1.0 × 10
−3
M was demonstrated.
Cryptopleurine Resistance: Genetic Locus for a 40
S
Ribosomal Component in
Saccharomyces cerevisiae
Authors: Grant Paul , Sánchez Lucas , Jiménez Antonio
Published: January 2020

Mutants resistant to the phenanthrene alkaloids tylophorine, tylocrebrine, and cryptopleurine have been isolated from the yeast
Saccharomyces cerevisiae
. A single recessive nuclear gene was responsible for resistance. This resistance locus,
cry
, was closely linked to the mating locus (2.2 centimorgans). The resistance was ribosomal and was due to an altered 40
S
ribosomal subunit. The mode of action of these drugs has been examined, and they appear to inhibit the translocation phase of protein synthesis.
Oxygen-dependent inactivation of glutamine phosphoribosylpyrophosphate amidotransferase in stationary-phase cultures of Bacillus subtilis
Authors: Turnbough C L , Switzer R L
Published: January 2020

Glutamine phosphoribosylpyrophosphate amidotransferase (ATase) activity is rapidly inactivated in stationary-phase cells of Bacillus subtilis. The inactivation of APase requires both the cessation of rapid cell growth and the presence of oxygen. ATase is inactivated in two protease-deficient mutant strains at a rate similar to that seen in the wild type, and is stable in anaerobic cell-free extracts of the parent strain. These results suggest that the inactivation of ATase is not the result of general proteolysis. The inactivation of ATase in stationary-phase cultures can be inhibited by oxygen starvation. This oxygen requirement does not reflect a dependence on the generation of metabolic energy, but appears to be a direct requirement for molecular oxygen. ATase synthesis is repressed by the addition of adenosine, and is inactivated only after the cessation of exponential growth. Addition of chloramphenicol or rifampin to exponential- and stationary-phase cells does not inhibit ATase inactivation, suggesting that protein or ribonucleic acid synthesis is not required for inactivation. ATase is inactivated at the end of exponential growth in cells that have exhausted a required amino acid.
Changes in the glutathione thiol-disulfide status of Neurospora crassa conidia during germination and aging
Authors: Fahey R C , Brody S , Mikolajczyk S D
Published: January 2020

Improved methods were developed for the determination of reduced glutathione (GSH), glutathione disulfide (GSSG), and protein-glutathione disulfide (PSSG) and applied to determine the glutathione status at various stages of the asexual life cycle for the band strain of Neurospora crassa. The GSH-GSSG ratio in freshly harvested dry conidia was found to be about 150 but decreased to around 6 when dryconidia were aged (stored) for 10 days after harvest. When conidia were germinated, this ratio increased to about 300 during the first 10 min of the 6-h germination process. In mycelia, during log-phase growth, the ratio was about 10-3. Changes in the ratio occurred primarily through changes in the GSSG content, which ranges from about 0.023 (mycelia) to 2(10-day aged conidia) mumol per g (dry weight) of residue, whereas GSH levels varied by a factor of about two. The PSSG content varied from 0.02 (mycelia) to 0.6 (10-day aged conidia) mumol per g (dry weight) of residue and generally paralleled the GSSG content. The results demonstrate the potential importance of thiol-disulfide reactions as a mechanism for the control of physiological properties associated with dormancy, and the observed changes in GSSG level are found to be compatible with the view that GSSG plays a role in the regulation of protein synthesis through control of polysome formation.
Polynucleotide sequence relationships among Ent plasmids and the relationship between Ent and other plasmids
Authors: So M , Crosa J H , Falkow S
Published: January 2020

Deoxyribonucleic acid-deoxyribonucleic acid hybridization studies reveal that the plasmids coding for the production of heat stable and heat labile enteroxtoxins of Escherichia coli, regardless of their origin, have a majority of their polynucleotide sequences in common, but are not related in any significant way to those plasmids coding for the synthesis of only ST toxin. The heat stable and heat labile plasmids also share a significant degree of their polynucleotide sequences with plasmids of the FI and FII incompatibility groups, but not with R factors belonging to the I, N, W, P, or X incompatibility groups.
Construction of a colicin E1-R factor composite plasmid in vitro: means for amplification of deoxyribonucleic acid
Authors: Tanaka T , Weisblum B
Published: January 2020

A composite plasmid has been constructed in vitro from colicin E1 factor (mass of 4.2 megadaltons [Md]) and nontransmissible resistance factor RSF 1010 (mass, 5.5. Md) deoxyribonucleic acids (DNAs) by the sequential action of Escherichia coli endonuclease (RI (Eco RI) and T4 phage DNA ligase on the covalently closed circular forms of the constituents. The composite plasmid was selected and amplified in vivo by sequential transformation of E. coli C600 with the ligated mixture and selection of transformants in medium containing streptomycin plus colicin E1, followed by amplification in the presence of chloramphenicol and purification of the extracted plasmid by dye-buoyant density gradient centrifugation in ethidium bromide-cesium chloride solution. Treatment of the composite plasmid with Eco RI yielded two fragments with mobilities corresponding to the linear forms of the parental plasmids, whereas Serratia marscesens endonuclease R (SmaR), which introduces a single scission in the colicin E1 factor but not in RSF 1010, convErted the composite plasmid to a single linear molecule (mass, 9.7 Md). Sequential degradation of colicin E1 factor with Sma R and Eco RI produced two fragments with masses of 3.5 and 0.7 Md; sequential degradation of RSF 1010 produced only one fragment (due to the cleavage with Eco RI), and sequential degradation of the composite plasmid produced the expected three fragments--an RSF 1010 Eco RI linear and the two expected products from the colicin E1 factor moiety. The composite plasmid conferred on the host cell resistance to streptomycin, sulfonamides, and colicin E1, but colicin E1 itself was not synthesized. In contrast, colicin E1 was synthesized by cells containing simultaneously both colicin E1 factor and RSF 1010 as separate entities. In the presence of chloramphenicol, the composite plasmid continued to replicate for 6 h. whereas replication of RSF 1010 and chromosomal DNA stopped within 2 h. Continued replication in the presence of chloramphenicol suggests that the replicator of the colicin E1 factor is functional in the composite plasmid.
Precursor relationship of phenylalanine transfer ribonucleic acid from Escherichia coli treated with chloramphenicol or starved for iron, methionine, or cysteine
Authors: Juarez H , Skjold A C , Hedgcoth C
Published: January 2020

When treated with chloramphenicol, Escherichia coli 15T minus produces two new species (IV and V) of transfer ribonucleic acid specific for phenylalanine in addition to the major normal species (II) and two minor normal species (I and III), which are seen as distinct components upon fractionation by chromatography on columns of benzoylated diethylaminoethyl-cellulose. Species IV is produced when cells are grown in iron-deficient medium and is, therefore, probably deficient in the 2-methylthio modification of N-6-(delta-2-isopentenyl) adenosine. A new minor species (Va) also appears under those conditions. All of the new components elute earlier than the major normal species. Addition of chloramphenicol to iron-deficient cells leads to the production of species V, and that production is blocked by rifampin, as is the production of species IV. Thus, species IV and V appear to be transcriptional products. Although E. coli 15T minus appears to be rel plus, starvation for methionine or cysteine leads to the accumulation of species IV (without addition of chloramphenicol); rifampin blocks the accumulation. Species V is still produced on addition of chloramphenicol to starved cultures. Starvation for arginine or tryptophan does not alter the chromatographic profile from the normal case. Treatment with permanganate indicates that species II and IV contain isopentenyladenosine but that species V does not. Species V appears to be deficient in both isopentenyl and methylthio modifications of adenosine and perhaps at least one other modification, because removing the isopentenyl moiety from adenosine does not convert species IV into species V, but converts it into species Va. A precursor relationship among species V, VI, and II is suggested by following the chromatographic profile of phenylalanine transfer ribonucleic acid during recovery of E. coli from treatment with chloramphenicol; the various species increase and decrease in a sequential manner.
Uptake of adenosine 5'-monophosphate by Escherichia coli
Authors: Yagil E , Beacham I R
Published: January 2020

Adenosine 5'-monophosphate is dephosphorylated before its uptake by cells of Escherichia coli. This is demonstrated by using a radioactive double-labeled culture, and with a 5'-nucleotidase-deficient, mutant strain. The adenosine formed is further phosphorolyzed to adenine as a prerequisite for its uptake and incorporation. The cellular localization of the enzymes involved in the catabolism of adenosine 5'-monophosphate is discussed.
Role of vitamin K2 in the organization and function of Staphylococcus aureua membranes
Authors: Goldenbaum P E , Keyser P D , White D C
Published: January 2020

A mutant of Staphylococcus aureus auxotrophic for menadione (a vitamin K2 precursor) was used to study the effects of menadione deprivation on the structure and function of the cell membrane. The phospholipid composition and metabolism was essentially unaltered by menadione deprivation. Removal of this percursor caused cellular levels of the cytochromes, protoheme, vitamin K2, and several membrane-bound flavoprotein dehydrogenase activities to decrease as a function of growth dilution. The cytochromes were enzymatically reducible and maintained in the same proportions as menadione-supplemented cells. Oxidative phosphorylation, however, was reduced more than 10-fold and membrane vesicles obtained from menadione-deprived cells were unable to couple glycine transport to L-lactate oxidation. Succinic dehydrogenase and adenosine 5' triphosphate hydrolysis appeared unaffected by menadione deprivation. These data suggest that menadione deprivation in the mutant stops the synthesis of vitamin K2 and other electron transport chain components and prosthetic groups. Although individual electron transport chain members remained fully functional during menadione deprivation, the overall efficiency of the chain, measured in terms of its function in electron transport, oxidative phosphorylation, and electron transport chain-linked transport, dropped greatly. This suggests that the synthesis of vitamin K2 is modulated to the synthesis of other components of the electron transport system, and that their organization into a functional system requires a specific concentration of vitamin K2 with respect to total membrane lipid.
Mutation affecting regulation of synthesis of acetohydroxy acid synthetase in Escherichia coli K-12
Authors: Jackson J H , Henderson E K
Published: January 2020

Altered regulation of synthesis of acetohydroxy acid synthetase (AHAS) was previously reported in a mutant of Escherichia coli strain K-12. The mutant strain, growing in minimal medium, exhibits a partial growth limiatation and derepression of AHAS, owing to deficient synthesis of isoleucine. The genetic lesion (ilvE503) causing the isoleucine limitation was shown to cause derepression of a valine-sensitive AHAS activity. The derepression effect of the ilvE503 mutation upon synthesis of AHAS was conclusively demonstrated by introducing both the ilvE503 allele and an altered AHAS (ilv-521) into the same cell. Evidence is presented that suggests the presence of multiple genetic regions for synthesis and control of the valine-sensitive AHAS activity.
Sedimentation analysis of deoxyribonucleic acid from thymine-starved Escherichia coli
Authors: Nakayama H , Hanawalt P
Published: January 2020

During thymine starvation, strand breaks accumulate in the chromosomal deoxyribonucleic acid (DNA) of Escherichia coli. This effect occurs to a varying extent in different strains and is particularly enhanced in strains deficient in DNA polymerase I. The inhibition of ribonucleic acid or protein synthesis suppresses the accumulation of strand breaks. In a polA strain, rifampin is more effective than chloramphenicol or puromycin in suppressing strand break accumulation. To a certain extent the pehenomenon othymineless death correlates with the appearance of strand breaks. Although the killing can not be explained by the bulk of strand breaks, it is possible that some of them represent lethal events. On the basis of our observations we proposed the following model. (i) Transcription may be accompanied by single-strand breaks in DNA. (ii) DNA polymerase I is involved in the efficient repair of these breaks. (iii) Thymine deprivation results in the accumulation of unrepaired breaks. (iv) Polymerase I-mediated repair is less affected by thymine deprivation than are the alternative pathways because it closes the breaks with short patches, requiring less thymine.
Isolation of super-repressor mutants in the histidine utilization system of Salmonella typhimurium
Authors: Hagen D C , Gerson S L , Magasanik B
Published: January 2020

Two super-repressor mutations in the histidine utilization (hut) operons of Salmonella typhimurium are described. Cells bearing either of these mutations have levels of hut enzymes that do not increase above the uninduced levels when growth is in the presence of either histidine or the gratuitous inducer imidazole propionate. Both mutations lie in the region of the gene for the hut repressor, hutC, and reverse mutations of both are to the constitutive (repressor-negative) rather than to the inducible (wild type) phenotype. In hybrid merodiploid strains the super-repressor mutations are dominant over either wild-type (hutC+) or repressor-negative (hutC-) alleles. Whereas both super-repressor mutations cause the uninducible synthesis of hut enzymes, the degree of repression is different. One mutation causes repression of enzyme synthesis in one of the two hut operons to a level below the basal, uninduced level of wild-type cells. The other mutation causes repression to a lesser degree than in wild-type cells, so that the hut enzymes are present at a level above the normal basal level; this partially constitutive synthesis is greater for the enzymes of one of the hut operons than for the enzymes of the other. Thus, both mutations apparently result in repressors with altered operator-binding properties, in addition to altered inducer-binding properties.
Marker discrimination in deoxyribonucleic acid-mediated transformation of various Pneumococcus strains
Authors: Tiraby G , Fox M S , Bernheimer H
Published: January 2020

The function responsible for discrimination among markers (point mutations) in Pneumococcus (hex) was traced back to the early strains used to demonstrate the chemical basis of transformation in the early 1940s. Those currently used laboratory strains failing to manifest this function arose from a single subline of the original strain. The function was also evident in other independently isolated strains including a number of different serological types. The hex function was not evident in transformation between heterologous pneumococcal strains probably as a result of the sensitivity of the function to saturation in the presence of deoxyribonucleic acid from closely related but nonisogenic strains.
l-amino acid oxidases of Proteus rettgeri
Authors: Duerre J A , Chakrabarty S
Published: January 2020

Proteus rettgeri has been found to contain two separable 1-amino acid oxidases. Both enzymes are particulate in nature, neither being ribosomal bound. One of these enzymes appears to have broad specificity, being active toward monoaminomonocarboxylic, imino, aromatic, sulfur-containing, and beta-hydroxyamino acids. The other enzyme has more limited specificity, catalyzing the oxidative deamination of the basic amino acids and citrulline. The affinity of this oxidase for the various substrates at pH 7.6 in decreasing order is arginine, histidine, ornithine, citrulline, and lysine. This enzyme has a particularly high affinity for arginine (Km equal to 0.27 mM), and anomalous kinetics are observed with increasing substrate concentrations. When concentrations of arginine greater than 1.0mM were added to the reaction containing histidine, imidazole pyruvate formation was completely inhibited.
Citrate uptake in membrane vesicles of Klebsiella aerogenes
Authors: Johnson C L , Cha Y A , Stern J R
Published: January 2020

In whole cells of Klebsiella aerogenes grown anaerobically on citrate as sole carbon source, citrate uptake is followed by rapid catabolism of the substrate via the inducible citrate fermentation pathway. Membrane vesicles prepared from such cells take up citrate but do not catabolize it. Vesicles process d-lactate dehydrogenase and the Na+-requiring oxalacetate decarboxylase. Citrate is taken up in the presence of Na+, and other monovalent cations, such as NH4+, Rb+, Cs+, or K+, do not substitute for Na+. Li+ appears to act synergistically with Na+. Citrate uptake is inhibited by N-2, cyanide, azide, sulfhydryl reagents, dinitrophenol, fluorcitrate, and hydroxycitrate.
F deoxyribonucleic acid transferred to recipient cells in the presence of rifampin
Authors: Hiraga S , Saitoh T
Published: January 2020

When Escherichia coli F+ cells resistant to rifampin and streptomycin are mated with F- cells sensitive to the antibiotics, a large fraction of F factor deoxyribonucleic acid (DNA), which is transferred to the recipient cells in the presence of either of the antibiotics, can be recovered as covalently closed, circular double-stranded DNA, as in the control mating in the absence of antibiotic. Similar results were obtained in the presence of chloramphenicol or chloramphenicol plus rifampin. It is suggested that the transferred single-stranded F DNA can be converted to the covalently closed, circular double-stranded form in the absence of protein synthesis, and that rifampin-sensitive transcription is not required for the conversion.
Molecular mechanisms of accommodation in Escherichia coli to toxic levels of Cd2+
Authors: Mitra R S , Gray R H , Chin B , Bernstein I A
Published: January 2020

Cells of Escherichia coli strain B develop large intracellular vacuoles and exhibit an abnormally long lag phase when inoculated into a defined medium to glucose and salts containing 3 times 10-6 M Cd2+. Early in this lag, about 95% of the cells fail to form colonies when plated on nutrient broth-NaCl-agar. Prior to the initiation of proliferation, the morphology of these cells becomes normal. They regain viability in the absence of deoxyribonucleic acid replication. The rate and extent of growth are normal once proliferation begins. This reversible phenomenon of accommodation to a growth-inhibiting concentration of Cd2+ does not appear to result from a selection of mutant cells. Cells which are proliferating in the presence of Cd2+ accumulate the ion to a very high concentration. In membranes and 31% in the cytoplasm. In unaccommodated cells, the figures are 2%, 75%, and 23%, respectively. The activity of alkaline phosphatase, a zinc-metalloenzyme which is inhibited by cadmum and is located between cell wall and membrane, is not abnormally low in accommodated cells, suggesting that the cadmim is compartmentalized in these cells. Molecular sieve chromatography of cell extracts shows that the Cd2+ is associated with two classes of macromolecules. It appears that accommodation of E. coli to the presence of Cd2+ involves exclusion of the ion from the cell and reversal of damage caused by prior exposure to the ion.
Biochemistry and genetics of Klebsiella pneumoniae mutant strains unable to fix N2
Authors: St John R T , Johnston H M , Seidman C , Garfinkel D , Gordon J K , Shah V K , Brill W J
Published: January 2020

Selected mutant strains of Klebsiella pneumoniae that are unable to fix nitrogen have been characterized according to nitrogenase component activity as well as antigenic cross-reacting material. The lesions in these strains have been mapped by transduction, and the results indicate that there are at least five genes specifically responsible for nitrogen fixation in vivo. Besides genes that specify the structure of the two nitrogenase components, there is a gene for a factor that is required for component I activity and a gene that codes for a factor possibly involved in electron transport to component II. A mutation in another site does not allow the organism to produce either of the nitrogenase components. All of these genes are co-transducible with the gene that specifics the structure of histidinol dehydrogenase.