bluuebunny/crossref_metadata_2025 huggingface dataset:
Nature of the Specificity of Alcohol Coupling to
l
-Alanine Transport into Isolated Membrane Vesicles of a Marine Pseudomonad
Authors: Sprott G. Dennis , MacLeod Robert A.
Published: January 2020

Ethanol stimulated the uptake of
l
-alanine into isolated membrane vesicles of a marine pseudomonad at a rate and to an extent comparable with that obtained with reduced nicotinamide adenine dinucleotide (NADH) or the artificial electron donor ascorbate-
N, N, N′, N′
-tetramethyl-
p
-phenylenediamine (ascorbate-TMPD). Methanol and branched-chain alcohols had little or no capacity to energize transport. No quantitative relationship was found between the ability of a compound to induce oxygen uptake and to energize transport, since with ethanol initial rates of oxygen uptake were approximately 4% of that obtained with NADH or ascorbate-TMPD. Cytochrome analysis revealed that NADH and ethanol reduced cytochromes
b
and
c
, whereas ascorbate-TMPD coupled primarily at the level of cytochrome
c
. Approximately 25% of the cytochromes reduced by dithionite were reducible by ethanol. Ethanol reduction of both cytochromes
b
and
c
was prevented by 2-heptyl-4-hydroxyquinoline-
N
-oxide,
p
-chloromercuribenzoate,
N
-ethylmaleimide, and iodoacetate. The ethanol- and NADH-energized transport systems for
l
-alanine were subject to quantitatively similar inhibition by cyanide, 2-heptyl-4-hydroxyquinoline-
N
-oxide, 2, 4-dinitrophenol, and the sulfhydryl reagents
p
-chloromercuribenzoate,
N
-ethylmaleimide, and iodoacetate. In contrast, for ascorbate-TMPD-driven transport, only cyanide and 2, 4-dinitrophenol remained fully effective as inhibitors,
p
-chloromercuribenzoate was only half as effective, and the other compounds stimulated transport. Inhibition of ethanol oxidation strikingly paralleled the inhibition of ethanol-driven transport for each of the inhibitors, including 2, 4-dinitrophenol. Marked differences between inhibition of oxygen uptake and inhibition of transport were observed when NADH or ascorbate-TMPD were the electron donors. The data indicate that only a small proportion of the respiratory chain complexes in the membrane vesicles are involved in transport and these are efficiently coupled to ethanol oxidation. The results also suggest that when 2, 4-dinitrophenol inhibits transport it is not acting as an uncoupling agent.
Mutants of the Pentose Phosphate Pathway in
Aspergillus nidulans
Authors: Hankinson Oliver
Published: January 2020

Mutants of the pentose phosphate pathway have been isolated in
Aspergillus nidulans
. These fail to grow on a variety of carbohydrates that are catabolized through the pentose phosphate pathway. They also grow poorly on nitrate and nitrite as sole nitrogen sources. The pentose phosphate pathway mutations have been assigned to two unlinked genes. Mutants with lesions in the
pppB
locus have reduced activities of four enzymes of the pentose phosphate pathway, of glucose-phosphate isomerase, and of mannitol-1-phosphate dehydrogenase.

pppA
−

mutants have elevated activities of these same enzymes except for transaldolase, for which they have much reduced activity. Both classes of mutants accumulate sedoheptulose-7-phosphate to an extent that is increased considerably when nitrate is present in the medium. Nitrate does not cause an increase in accumulation of sedoheptulose-7-phosphate in double mutants which, in addition to the
pppA1
mutation, carry a mutation that leads to the lack of nitrate reductase activity. These last results suggest that nitrate stimulates the flux through the oxidative pentose phosphate pathway, but that this stimulation depends upon the metabolism of nitrate.
Deoxyribonucleic Acid Synthesis During the Division Cycle of
Escherichia coli
: a Comparison of Strains B/r, K-12, 15, and 15T
−
Under Conditions of Slow Growth
Authors: Gudas Lorraine J. , Pardee Arthur B.
Published: January 2020

The rates of deoxyribonucleic acid (DNA) synthesis during the division cycles of the
Escherichia coli
strains B/r, K-12 3000, 15T
−
, and 15 have been measured in synchronous cultures, under several conditions of slow growth. These synchronous cultures were obtained by sucrose gradient centrifugation of exponentially growing cultures, after which the smallest cells were removed from the gradient and allowed to grow. Sucrose gradient centrifugation did not adversely affect the cell cycle, since an experiment in which an exponentially growing culture was pulsed with [
3
H]thymidine prior to the periodic separation and assay of the smallest cells resulted in the same conclusions, as given below. In the strains of
E. coli
that were studied, a decreased rate of [
3
H]thymidine incorporation was seen late in the cell cycle, prior to cell division. No decrease in the rate of [
3
H]thymidine incorporation was seen at or near the beginning of the cell cycle. Thus, all these strains appear to regulate DNA synthesis in a similar fashion during slow growth. In addition, a correlation between the appearance of cells with visible cross-walls and the start of a new round of DNA synthesis was seen, indicating that these two events might be related.
Transductional Analysis of theleu-thrRegion of Chromosome ofSerratia marcescens
Authors: Matsumoto Hideki , Tazaki Tadakatu , Hosogaya Shigemi
Published: January 2020

Transductional analysis of the chromosomal linkage map ofSerratia marcescensnearleurevealed the following order of loci:ser4-thr3-pyr1-pdx2-leu1-azi8.
Examination of Isolated Yeast Cell Vacuoles for Active Transport
Authors: Nakamura K. D. , Schlenk F.
Published: January 2020

Isolated vacuoles of the yeast
Candida utilis
did not show active transport of
S
-adenosylmethionine, uric acid, and several amino acids which they concentrate in vivo.
Biosynthesis of Ubiquinone in
Escherichia coli
K-12: Biochemical and Genetic Characterization of a Mutant Unable to Convert Chorismate into 4-Hydroxybenzoate
Authors: Lawrence J. , Cox G. B. , Gibson F.
Published: January 2020

A mutant strain of
Escherichia coli
unable to carry out the first specific reaction of ubiquinone biosynthesis, that is the conversion of chorismate into 4-hydroxybenzoate, has been isolated. The gene concerned maps at about minute 79 on the
E. coli
chromosome and has been designated
ubiC
. This gene is probably the structural gene for chorismate lyase since cell extracts from a transductant strain carrying the
ubiC437
mutant allele are unable to convert chorismate into 4-hydroxybenzoate and growing cells of the mutant do not form appreciable quantities of ubiquinone unless 4-hydroxybenzoate is added to the growth medium.
Microtubule Assembly and Function in
Chlamydomonas
: Inhibition of Growth and Flagellar Regeneration by Antitubulins and Other Drugs and Isolation of Resistant Mutants
Authors: Flavin Martin , Slaughter Clarence
Published: January 2020

The distribution of microtubules in
Chlamydomonas reinhardtii
suggests that they are involved in mitosis, cell and nuclear cleavage, and generation of flagella. Vinblastine, colchicine, and podophyllotoxin bind to the protein building block of microtubules (tubulin) and prevent normal assembly. Mutants resistant to these “antitubulin” drugs are candidates to have alterations in tubulin primary structure. We report the ability to inhibit growth, and flagellar regeneration after amputation, of: vinblastine, several colchicine derivatives, two water-soluble derivatives of podophyllotoxin (succinylpodophyllotoxin and epipodophyllotoxin thiuronium bromide), and other substances which may interfere with flagellar assembly or motility (isopropyl
N
-phenyl carbamate, 2-methoxy-5-nitrotropone, chloral hydrate, caffeine, and nickel acetate). The ability of each drug to inhibit binding of labeled colchicine or podophyllotoxin to mammalian brain tubulin was also determined. The results suggest that only in the cases of colchicine, colcemide, and epipodophyllotoxin thiruonium bromide was the toxicity to
Chlamydomonas
mediated by inhibition of tubulin assembly. The requirement for high concentrations of colchicine may be due to permeability barriers, since colchicine toxicity was potentiated by deoxycholate. Mutants resistant to antitubulins were isolated after treatment with methyl methanesulfonate. The results with vinblastine were equivocal. Of three mutants resistant to inhibition of growth and flagellar regeneration by colchicine, one was also cross-resistant to epipodophyllotoxin thiuronium bromide.
Characterization of
Bacillus licheniformis
6346 Mutants Which Have Altered Lytic Enzyme Activities
Authors: Forsberg C. W. , Rogers H. J.
Published: January 2020

Two groups of mutants altered in lytic enzyme activities have been isolated from
Bacillus licheniformis
6346 MH-1 by screening clones for halo production in agar plates containing cell wall conjugated with Procion brilliant red. In the first group which produced halos during colony formation, two were shown to contain three- and eightfold more muramyl-
l
-alanine amidase than the parent. These strains liberated amidase and intracellular α-glucosidase into the culture medium during exponential growth in liquid medium. Isolated walls had a normal qualitative composition and in autolysing liberated N-terminal amino acids and reducing groups. Wall preparations from the second group of mutants which did not produce halos lysed very poorly at pH 9.5, the optimal pH for amidase activity, and poorly at pH 5.5 even though they had similar endo-
N
-acetylglucosaminidase activities to the parent. Two of these strains that were also deficient in phosphoglucomutase had only 3 to 5% of the membrane-bound amidase activity compared with that in the parent. Cell walls of the phosphoglucomutase-deficient mutants treated with sodium dodecyl sulfate to inactivate endogenous lytic enzymes were dissolved at 10% of the rate of those from the parent by added amidase, but their sensitivities to lysozyme were similar. Those from one mutant had 10 to 20% of the amidase-binding capacity of parent walls, whereas its isolated mucopeptide was essentially inactive in this respect. The failure of these phosphoglucomutase-deficient mutants to autolyse is likely to be due to the combined effects of both low amidase activity and resistant walls. As a result, daughter cells are unable to separate and long chains are formed during exponential growth.
Microbial Degradation and Assimilation ofn-Alkyl-Substituted Cycloparaffins
Authors: Beam H. W. , Perry J. J.
Published: January 2020

Studies were conducted on the oxidation and assimilation ofn-alkyl-substituted cycloalkane substrates by several hydrocarbon-utilizing microorganisms. These microorganisms utilized heptadecylcyclohexane and dodecylcyclohexane as the sole source of carbon and energy. Neither methylcyclohexane nor ethylcyclohexane was utilized as a growth substrate by any organisms tested. Gas-liquid chromatographic analyses of fatty acids present in cells after growth on dodecylcyclohexane confirm direct incorporation of both alpha- and beta-oxidation products. Growth patterns of these organisms onn-alkyl-substituted cyclohexane fatty acids of varying chain lengths suggest a greater probability of ring cleavage when the side chain contains an odd number of carbons.
Detachment and Chemical Characterization of the Regularly Arranged Subunits from the Surface of an
Acinetobacter
Authors: Thornley Margaret J. , Thorne Kareen J. I. , Glauert Audrey M.
Published: January 2020

Acinetobacter
sp. strain MJT/F5/199A carries an array of tetragonally arranged subunits on its outer surface. The subunits can be detached from isolated cell walls by incubation with 1 M urea or by washing with water after treatment with 10 mM ethylenediaminetetraacetic acid or ethyleneglycol-bis(β-aminoethylether)
N,N
′-tetraacetic acid. After removal of the urea, they reaggregate into the same ordered array at air-water interfaces in the presence of MgCl
2
. The detached subunits were characterized as an acidic protein of molecular weight 65,000. They represent one-fifth of the total cell wall protein.
Isolation and Purification of Prodigiosin from
Vibrio psychroerythrus
Authors: D'Aoust J. Y. , Gerber Nancy N.
Published: January 2020

The red pigment of
Vibrio psychroerythrus
(formerly marine psychrophile NRC 1004) was identified as prodigiosin by comparison of its mass spectrum, absorption spectrum in the visible range, and chromatographic behavior with prodigiosin isolated from
Serratia marcescens
. The properties of the
V. psychroerythrus
pigment were clearly distinguishable from five other prodigiosin-like compounds isolated from three different microorganisms.
Sugar Metabolism in Transketolase Mutants of
Escherichia coli
Authors: Josephson Betty L. , Fraenkel D. G.
Published: January 2020

This paper continues the description of transketolase mutants of
Escherichia coli
; they are absolutely unable to grow on pentoses, but slightly “leaky” with respect to their aromatic requirement (B. L. Josephson and D. G. Fraenkel, 1969). Several experiments have explored the degree of leakiness and shown it to be low. There is little conversion of radioactive xylose to carbon dioxide. The labeling of ribose in cells grown on [1-
14
C]glucose and [2-
14
C]glucose accords with its origin being chiefly by the oxidative pathway. A mutant lacking both transketolase and gluconate-6-phosphate dehydrogenase has been constructed; it requires supplementation with pentose. Pentoses are inhibitory to growth of transketolase mutants, but high levels of pentose phosphates do not accumulate in this situation. Several experimental results are suggestive of regulation of metabolic flow in the oxidative branch of the hexose monophosphate shunt.
In Situ Activity of Enzymes on Polyacrylamide Gels of a Deoxyribonucleic Acid-Membrane Fraction Extracted from Pneumococci
Authors: Firshein William
Published: January 2020

A deoxyribonucleic acid (DNA)-membrane fraction extracted from
Diplococcus pneumoniae
was subjected to polyacrylamide gel electrophoresis after treatment with 0.16% sodium dodecyl sulfate. At least two DNA polymerase activities were detected by in situ assays with appropriate substrates, templates, and inhibitors, including a co-polymer of deoxyadenylic and thymidylic acid and
N
-ethylmaleimide. This activity coincided with a fraction in the gel containing 7.5, 9.4, and 24%, respectively of the DNA, phospholipid, and protein present in the DNA-membrane fraction before electrophoresis and sodium dodecyl sulfate treatment. Assays with minced gels showed that several nuclease activities, deoxyribonucleotide kinase activity, and DNA ligase activity also coincided with this fraction. However, ribonucleoside diphosphate reductase activity did not. These results demonstrate that a complex of enzymes involved in DNA replication is firmly bound to the DNA-membrane fraction in pneumococci.
Chemical and Physical Properties of Lipopolysaccharide of
Yersinia pestis
Authors: Hartley James L. , Adams Gordon A. , Tornabene Thomas G.
Published: January 2020

Lipopolysaccharide (LPS) prepared from
Yersinia pestis
195/P contained
d
-glucose,
d
-glycero-
d
-mannoheptose,
l
-glycero-
d
-mannoheptose, glucosamine, 3-deoxyoctulosonic acid, lipid A, β-hydroxymyristate, acetyl, phosphate, and protein. Traces of ethanolamine, mannose, and galactose were also detected. The lipid A moiety was composed of glucosamine substituted with phosphate, amide-linked β-hydroxymyristate, and amide-bound acetate. The absence of significant amounts of additional fatty acids indicates a lipid A structure somewhat less complex than that of other gram-negative bacteria. The sugars identified are those generally found in the “core” region of LPS from the
Enterobacteriaceae
, with the exception of the
d
-glycero-
d
-mannoheptose. The molecular weight of the aggregated LPS was estimated to be 1.6 × 10
8
.
Specificity and Induction of Undecyl Acetate Esterase from
Pseudomonas cepacia
Grown on 2-Tridecanone
Authors: Shum A. C. , Markovetz A. J.
Published: January 2020

Undecyl acetate esterase from
Pseudomonas cepacia
grown on 2-tridecanone was strongly inhibited by organophosphates and other esterase inhibitors. Also,
p
-chloromercuribenzoate at 1 × 10
−4
M showed a 70% inhibition of esterase activity. The enzyme hydrolyzed both aliphatic and aromatic acetate esters at substrate concentrations of 0.25 M. Under these conditions the highest reaction rate was toward undecyl acetate. No lipase or proteolytic activity was demonstrated. Undecyl acetate esterase was classified as a carboxylesterase (B-esterase). Cell-free activity studies on the production of undecyl acetate esterase grown on different carbon sources plus zymogram studies demonstrated that the enzyme was inducible when 2-tridecanone, 2-tridecanol, undecyl acetate and, to a lesser extent, 1-undecanol were growth substrates. Induction of undecyl acetate esterase during oxidation of 2-tridecanone supports the view that undecyl acetate is an intermediate in the degradation of the methyl ketone.
Effect of Ethidium Bromide on Elimination of Exfoliative Toxin and Bacteriocin Production in
Staphylococcus aureus
Authors: Warren Richard , Rogolsky Marvin , Wiley Bill B. , Glasgow Lowell A.
Published: January 2020

The scalded skin syndrome has been associated with phage group II staphylococci. The clinical manifestations of scalded skin syndrome, Ritter's disease, scarlatiniform erythema, and localized bullous impetigo, are due to the production of an extracellular protein, designated exfoliative toxin. Phage group II staphylococci can also produce an extracellular protein, bacteriocin, which is bacteriocidal for specific gram-positive microorganisms. Strain UT 0007 produces both bacteriocin and exfoliative toxin which appear to be products of extrachromosomal genes. These genes are jointly eliminated from strain UT 0007 after growth in either ethidium bromide or at high temperatures.
Pleiotropic Alteration of Activities of Several Toxins and Enzymes in Mutants of
Staphylococcus aureus
Authors: Yoshikawa Masanosuke , Matsuda Futami , Naka Machiko , Murofushi Etsuyo , Tsunematsu Yukinori
Published: January 2020

Pleiotropic alteration of several genetic characters including toxin production was quantitatively shown with a strain of
Staphylococcus aureus
of phage type 80, 81 which had been given a very specific genetic marker (temperature sensitivity of mannitol fermentation) to avoid confusion by contamination. Thus, alpha-hemolysin hyperproducers obtained by
N
-methyl-
N
′-nitro-
N
-nitrosoguanidine (NTG) mutagenesis were very often hyperproducers of DNase, coagulase, and protease. Their colonies were less yellow than the parent. DNase hyperproducers obtained after NTG mutagenesis were also often hyperproducers of alpha-hemolysin, coagulase, and protease, with colonies less yellow than the parent. Almost all of the revertants obtained by mutagenesis with ethyl methane sulfonate with respect to alpha-hemolysin or DNase were shown to have simultaneously become hypoproducers of alpha-hemolysin, DNase, and protease. Since the pleiotropic alteration of multiple functions was thus quantitatively confirmed, the mechanism underlying this phenomenon should probably be related to a regulatory mechanism common to them.
Role of the ø11 Phage Genome in Competence of
Staphylococcus aureus
Authors: Sjöström Jan-Eric , Philipson Lennart
Published: January 2020

Both phage ø11 and 83A, when present as prophage or when used as helper phage, induce competence for transfection and transformation to the same level in
Staphylococcus aureus
, strain 8325-4. Cells lysogenized with certain temperature-sensitive (
ts
) mutants of phage ø11 show competence at the nonpermissive temperature (41 C) without production of infectious phages. Phage ø11
ts
allele 31 can neither as a prophage nor as a helper phage develop competence under nonpermissive conditions. This mutant appears, therefore, to be mutated in the region of the phage genome controlling competence. The competence level for both transfection and transformation is increased by superinfecting strain 8325-4 (ø11) or 8325-4 (83A) at high multiplicities with phage ø11 with some of its mutants or with phage 83A. This superinfection enhancement appears to require protein synthesis but not deoxyribonucleic acid synthesis as judged from studies with inhibitors of macromolecular synthesis. Besides the phage particle, no extracellular or cell-bound factors so far detected can induce competence. The phage-induced product conferring competence is rapidly synthesized by strain 8325-4 (
ts
ø11
31
) after shift to permissive conditions, but requires deoxyribonucleic acid and protein synthesis to be expressed. Recombination between the
sus
mutants of phage ø11 of Kretschmer and Egan and
ts
ø11
31
indicate that competence is controlled by an early gene in the lytic cycle which may be expressed also in lysogenic cells. The phage product inducing competence appears to have a half-life of 10 to 15 min in the conditional lethal mutant at shift to nonpermissive temperature. Ultraviolet inactivation of phage ø11 infectivity occurs more rapidly than inactivation of competence induction. In fact, the number of transformants is increased at low doses of irradiation. Competence induction is, however, decreased at high does of ultraviolet irradiation.
Pleiotropic Effects of Mutations Involved in the Regulation of
Escherichia coli
K-12 Alkaline Phosphatase
Authors: Morris Howard , Schlesinger Milton J. , Bracha Moshe , Yagil Ezra
Published: January 2020

Induction of alkaline phosphatase in wild-type
Escherichia coli
K-12 leads to the appearance of three new proteins in addition to alkaline phosphatase in the periplasmic space of the bacteria. These proteins are detected in autoradiograms of sodium dodecyl sulfate-acrylamide gel electropherograms of extracts from cells labeled with [
35
S]methionine. Studies with constitutive mutants defective in the three genes
phoS, phoT
, and
phoR
that have been shown to regulate alkaline phosphatase synthesis indicate that the three periplasmic proteins are coregulated with alkaline phosphatase. A mutant that has a deletion in the alkaline phosphatase structural gene
phoA
produces the three proteins, but a newly discovered mutant
phoB
that has a defect in the expression of alkaline phosphatase fails to produce the three proteins.
phoB
mutants are shown here to be unable to make detectable amounts of alkaline phosphatase polypeptides, as measured by immunoprecipitins or acrylamide gel electropherograms. On the basis of these results we suggest a new model for the regulation of alkaline phosphatase biosynthesis. In this model, a ternary complex composed of
phoB
+
and
phoR
+
gene products and an internal metabolite functions as a positive control element to regulate the transcription of several cistrons coding for periplasmic proteins.
Participation of Lipopolysaccharide Genes in the Determination of the Enterobacterial Common Antigen: Analysis of R Mutants of
Salmonella minnesota
Authors: Mäkelä P. Helena , Mayer H. , Whang H. Y. , Neter E.
Published: January 2020

A series of R (rough)
Salmonella minnesota
mutants with
rfb, rfe
, and
rfa
mutations leading to various defects in the biosynthesis of cell wall lipopolysaccharide was analyzed as to their enterobacterial common antigen (CA) content. All mutants that had functional
rfe
genes were CA
+
as is the wild-type parent. This includes mutants with the most defective lipopolysaccharide core types, demonstrating that core structures are not a necessary part of CA. All
rfe
−
mutants (complete lipopolysaccharide core, defective synthesis of O side chains) were defective in the synthesis of CA. A smooth strain was accidentally found to be CA
−
; the mutation responsible for this defect was also located, like
rfe
, very close to
ilv
.
Inhibition of Messenger Ribonucleic Acid Synthesis in
Escherichia coli
by Thiolutin
Authors: Khachatourians George G. , Tipper Donald J.
Published: January 2020

Thiolutin, at concentrations of 5 to 40 μg/ml, inhibited the induced synthesis of β-galactosidase in
Escherichia coli
CA8000. Thiolutin had no effect on the rate of in vitro hydrolysis of
o
-nitrophenyl-β-
d
-galactoside by purified β-galactosidase. Examination of the effects of thiolutin on the kinetics of appearance of β-galactosidase in the presence and absence of rifampin in induced
E. coli
cells indicated that thiolutin interferes with the transcription process at the level of elongation of messenger ribonucleic acid (mRNA) chains. The data indicated that, in the presence of thiolutin, β-galactosidase mRNA has a half-life of 1.6 min and that the first completed β-galactosidase mRNA is produced about 1.5 min after induction. These data are consistent with estimates of transcription time and messenger half-life obtained by conventional means, and suggest that thiolutin does not affect translation of mRNA or its breakdown in vivo. After removal of thiolutin, cells fully regained the ability to be induced for synthesis of β-galactosidase within 10 min, but mRNA which was incomplete at the time of thiolutin addition did not subsequently become functional.
Promoter-Like Mutation Affecting HPr and Enzyme I of the Phosphoenolpyruvate:Sugar Phosphotransferase System in
Salmonella typhimurium
Authors: Cordaro J. Christopher , Anderson R. Philip , Grogan E. Wayne , Wenzel Donald J. , Engler Michael , Roseman Saul
Published: January 2020

A promoter-like mutation,
ptsP160
, has been identified which drastically reduces expression of the genes specifying two proteins, HPr and enzyme I, of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) in
Salmonella typhimurium
. This mutation lies between
trzA
, a gene specifying susceptibility to 1,2,4-triazole, and
ptsH
, the structural gene for HPr. It leads to a loss of active transport of those sugars that require the PTS for entry into the cell. Pseudorevertants of strains carrying this promoter-like mutation have additional lesions very closely linked to
ptsP160
by transduction analysis and are noninducible for HPr and enzyme I above a basal level. Presumably, strains carrying
ptsP160
are defective in the normal induction mechanism for HPr and enzyme I, and the pseudorevertants derived from them result from second-site initiation signals within or near this promoter-like element. The induction of HPr and enzyme I above their noninduced levels apparently is not required for transport of at least one PTS sugar, methyl α-
d
-glucopyranoside, since this sugar is taken up by the pseudorevertants at the same rate as by the wild type. The existence of a promoter-like element governing the coordinate inducibility of both HPr and enzyme I suggests that
ptsH
and
ptsI
constitute an operon. Wild-type levels of a sugar-specific PTS protein, factor III, are synthesized in response to the
crr
+
gene in both a
ptsP160
strain and its pseudorevertants; this suggests that the
crr
+
gene has its own promoter distinct from
ptsP
.
Ultrastructural Analysis During Germination and Outgrowth of
Bacillus subtilis
Spores
Authors: Santo Leatrice Y. , Doi Roy H.
Published: January 2020

Electron microscopy of thin sections of dormant and germinating spores of
Bacillus subtilis
168 revealed a progressive change in the structure of the cortex, outer spore coat, and inner spore coat. The initial changes were observed in the cortex region, which showed a loose fibrous network within 10 min of germination, and in the outer spore coat, which began to be sloughed off. The permeability of the complex outer spore layers was modified within 10 min, since, at this time, the internal structures of the spore coat were readily stainable. A nicking degradation action of the laminated inner spore coat began at 20 min, and this progressed for the next 20 min leading to the loosening of the inner spore coat. By 30 min, the outer spore coat showed signs of disintegration, and at 40 min, both the outer and inner spore coats were degraded extensively. At 30 to 40 min, a period just preceding net deoxyribonucleic acid synthesis, mesosomes became very prominent in the inner spore core and the cell wall began to thicken around the spore core. At 50 min, an emerging cell was observed, and by 60 min, there was clear evidence for elongation of the emerging cell and the presence of two nuclear bodies. At 90 min, elongation had been followed by the first cell division. There was evidence for spore coat fragments at the opposite poles of the dividing cell.
Pyruvate Kinase of
Streptococcus lactis
Authors: Collins Louise B. , Thomas Terence D.
Published: January 2020

The kinetic properties of pyruvate kinase (ATP:pyruvate-phosphotransferase, EC 2.7.1.40) from
Streptococcus lactis
have been investigated. Positive homotropic kinetics were observed with phosphoenolpyruvate and adenosine 5′-diphosphate, resulting in a sigmoid relationship between reaction velocity and substrate concentrations. This relationship was abolished with an excess of the heterotropic effector fructose-1,6-diphosphate, giving a typical Michaelis-Menten relationship. Increasing the concentration of fructose-1,6-diphosphate increased the apparent

V
max

values and decreased the

K
m

values for both substrates. Catalysis by pyruvate kinase proceeded optimally at pH 6.9 to 7.5 and was markedly inhibited by inorganic phosphate and sulfate ions. Under certain conditions adenosine 5′-triphosphate also caused inhibition. The

K
m

values for phosphoenolpyruvate and adenosine 5′-diphosphate in the presence of 2 mM fructose-1,6-diphosphate were 0.17 mM and 1 mM, respectively. The concentration of fructose-1,6-diphosphate giving one-half maximal velocity with 2 mM phosphoenolpyruvate and 5 mM adenosine 5′-diphosphate was 0.07 mM. The intracellular concentrations of these metabolites (0.8 mM phosphoenolpyruvate, 2.4 mM adenosine 5′-diphosphate, and 18 mM fructose-1,6-diphosphate) suggest that the pyruvate kinase in
S. lactis
approaches maximal activity in exponentially growing cells. The role of pyruvate kinase in the regulation of the glycolytic pathway in lactic streptococci is discussed.
Ultraviolet Sensitivity of
Bacillus subtilis
Spores upon Germination and Outgrowth
Authors: Munakata Nobuo
Published: January 2020

A strain of
Bacillus subtilis
, UVSSP-42-1, which produces ultraviolet (UV)-sensitive spores and vegetative cells, was found to possess germinated spores 25 times more UV resistant than the resting spores. This relative resistance achieved upon germination was associated with the transition of the heat-resistant refractile spores to the heat-sensitive phase-dark forms. Several generations of outgrowth were required before the cells attained the level of UV sensitivity characteristic of the vegetative cell. The UV sensitivity of germinated spores was compared with other strains with various combinations of mutations affecting deoxyribonucleic acid repair capabilities. The presence of
hcr
and
ssp
mutations which are known to abolish the removal of photoproducts from deoxyribonucleic acid did not alter significantly the sensitivity of the germinated forms. However, the addition of the
recA
mutation and, to some extent, the
pol
mutation increased the UV sensitivity of the germinated spores. These results indicate that deoxyribonucleic acid repair mechanisms dependent on the
recA
gene are active in the germinated spores. The chemical nature of the damage repaired by the
recA
gene product is not known. This study indicates that the life cycle of sporulating bacilli consists of at least three photobiologically distinct forms: spore, germinated spore, and vegetative cell.
Regulation of the β-Glucoside System in
Escherchia coli
K-12
Authors: Prasad Ishwari , Schaefler Sam
Published: January 2020

In
Escherichia coli
wild-type cells, a mutation at the β-glucoside regulatory gene (
bglR
+
to
bglR
−
) leads to simultaneous expression of inducible phospho-β-glucosidase B (
bglB
+
) and a β-glucoside-specific species of enzyme II (β-glucoside transport I [
bglC
+
]); an additional mutation (
bglS
+
to
bglS4
) allows these enzymes to be formed constitutively. The
bgl
alleles have been mapped in the following order:
pyrE, bglA, bglB, bglS, bglR, bglC, ilvD
. The back mutation in the regulatory allele (
bglR
−
to
bglR
+
) caused the cessation of the expression of the
bglB
+
,
bglS
+
or
bglS4, bglC
+
alleles. However, a mutation in a strain with
bglB
+
,
bglS4, bglR8, bglC
+
alleles, at the
ini
site that lies between the
bglS4
and the
bglR8
allele, allowed the expression of the
bglS4
and
bglB
+
alleles, but showed no affect on the expression of the
bglC
+
allele. It is suggested that the
ini
mutation possesses a promotor-type function that in the absence of regulatory allele function (
bglR8
) renews the functioning of only the
bglS4
and
bglB
+
alleles. The complementation studies have shown that the
bglB
+
,
bglS
+
or
bglS4, bglC
+
alleles are expressed only in
cis
to the
bglR
−
allele. In the constitutive strain (
bglB
+
,
bglS4, bglR
−
,
bglC
+
), the expressed
bglS4
allele formed a soluble product that acts in
trans
over the
bglB
+
and
bglC
+
alleles and that appears effective only when the
bglB
+
and the
bglC
+
alleles are expressed in
cis
to the
bglR
−
allele. It thus showed that the constitutive biosynthesis of phospho-β-glucosidase B and β-glucoside transport I is under positive control. Since the regulatory allele
bglR
−
lies between the
bglS4
and the
blgC
+
alleles, and acts in
cis
, it appears that the mutation (
bglR
+
to
bglR
−
) allows the initiation of transcription in one direction to express the
bglS4, bglB
+
alleles and in the other to express the
bglC
+
allele. The structural genes
bglB
and
bglC
lie adjacent to the regulatory genes
bglR
and
bglS
, and the structural genes are coordinately controlled by the regulatory genes. It is, therefore, proposed that the
bglB, bglS, bglR, bglC
genes form a
bgl
operon.
Regulation of the Synthesis of the Lactose Repressor
Authors: Edelmann Patricia L. , Edlin Gordon
Published: January 2020

Measurements of the lactose repressor over a tenfold range of cell growth rates were made on protein extracts from
Escherichia coli
cultures grown in media with various carbon energy sources. The concentration of lactose repressor varied with the number of genome equivalents per cell over this range in growth rates, suggesting that the number of lactose molecules within the cell is determined by the number of
I
gene copies present. The timing of repressor synthesis during the cell division cycle and its correlation with deoxyribonucleic acid synthesis was examined by synchronizing the cell division cycle of
E. coli
ED1039, in which the Lac region has been transposed from 10 to 36 min on the genetic map. Measurements of lactose repressor in the synchronized culture revealed a burst of repressor synthesis at the time of
I
gene duplication. The concentration of lactose repressor was found to decrease as a function of total cell protein during the division cycle until an increase in synthesis occurred, suggesting that repressor synthesis probably does not occur throughout the division cycle. A model for
I
gene regulation is proposed.
Lipopolysaccharide Containing
l
-Acofriose in the Filamentous Blue-Green Alga
Anabaena variabilis
Authors: Weckesser J. , Katz A. , Drews G. , Mayer H. , Fromme I.
Published: January 2020

For the first time, an O-antigenic lipopolysaccharide (LPS) has been isolated from a filamentous blue-green alga (
Anabaena variabilis
). It was extractable with phenol-water, resulting in extraction of the bulk of the LPS into the phenol phase. The polysaccharide moiety of this LPS consists of
l
-rhamnose, its 3-O-methyl ether
l
-acofriose,
d
-mannose,
d
-glucose, and
d
-galactose.
l
-Glycero-
d
-mannoheptose and 2-keto-3-deoxyoctonate, the two characteristic sugar components of enteric LPS, and phosphate groups are absent from the
A. variabilis
O antigen. The only amino sugar present is
d
-glucosamine. Three hydroxy fatty acids were identified, namely, β-hydroxymyristic, β-hydroxypalmitic and β-hydroxystearic acids, in addition to palmitic and unidentified fatty acid. The LPS of
A. variabilis
is localized in the outermost cell wall layer and behaves like a bacterial O antigen in serological tests. The passive hemagglutination yielded high titers with isolated LPS (pretreated by heat or by alkali) and rabbit antisera prepared against living or heat-killed cells. The position of the precipitation arcs after immunoelectrophoresis of the O antigen indicates the lack of charged groups. The water phase of the phenol-water extract contains, in high yield, a glucose polymer. It is serologically inactive as shown by the passive hemagglutination test and by agar-gel precipitation.
Effect of Altered Sterol Composition on Growth Characteristics of
Saccharomyces cerevisiae
Authors: Thompson E. D. , Parks L. W.
Published: January 2020

The function of sterols in mitochondrial structures of yeast was examined. Sterol mutant strains were employed to examine the effects of altered sterolic content on optimal and permissive growth temperatures in respiring and fermenting cultures. Although fermentative growth was unaffected by sterol composition, a definite decrease in both the optimal and the permissive growth temperatures of respiring cultures was observed when ergosterol was replaced by Δ
8(9), 22
-ergostadiene-3β-ol. In vitro studies showed a similar decrease in membrane phase transition temperatures of the mitochondrial enzyme
S
-adenosylmethionine: Δ
24
-sterol methyltransferase in the mutant strains. Increased sterol and methyltransferase levels were detected in strains incapable of synthesizing ergosterol. A possible control function governing sterol synthesis is proposed for ergosterol.
Some Effects of Visible Light on
Escherichia coli
Authors: D'Aoust Jean Y. , Giroux J. , Barran L. R. , Schneider Henry , Martin W. G.
Published: January 2020

Light above 400 nm had selective effects on
Escherichia coli
ML-308: several processes or enzymes were strongly inhibited, whereas others were relatively unaffected. There was a correlation between the inhibition of respiration and the inhibition of active uptake of glycine. However, phenylalanine uptake did not show such a correlation. The decrease in adenosine 5′-triphosphate level during the first few minutes of illumination resembled the inactivation kinetics of phenylalanine uptake. The results suggest that phenylalanine uptake may not depend greatly on oxidative energy and may depend on the adenosine 5′-triphosphate level. The results for glycine suggest either that its active uptake and respiration involve a common photosensitive component or alternately, that only the respiratory chain contains the photosensitive component, and that glycine uptake is coupled almost exclusively to respiration. The critical photochemical lesion does not involve
d
-lactate dehydrogenase, succinate dehydrogenase, or
l
-α-glycerophosphate dehydrogenase since their inactivation rate is markedly lower than that for respiration.
Extracellular Enzyme From Myxobacter AL-1 That Exhibits Both β-1,4-Glucanase and Chitosanase Activities
Authors: Hedges Allan , Wolfe R. S.
Published: January 2020

An enzyme that has both β-1,4-glucanase and chitosanase activities is characterized. Evidence for homogeneity was obtained from electrophoresis and sedimentation velocity studies; only one N-terminal amino acid, valine, was found. Results of denaturation studies showed that β-1,4-glucanase and chitosanase activities decreased at equal rates. With carboxymethylcellulose as the substrate, a

K
m

of 1.68 g of carboxymethylcellulose per liter of solution and a

V
max

of 2.20 × 10
−9
mol/min were found. With chitosan (the β-1,4-polymer of glucosamine) as the substrate, a

K
m

of 0.30 g of chitosan per liter of solution and a

V
max

of 0.75 × 10
−9
mol/min were found. A pH optimum of 5.0 was found for β-1,4-glucanase activity, and pH optima of 5.0 and 6.8 were found for chitosanase activity. β-1,4-Glucanase activity had a temperature optimum of 38 C, and chitosanase activity had a temperature optimum of 70 C. Chitosan stabilized both enzyme activities at 70 C. Cellotriose was the smallest polymer capable of hydrolysis. Glucosamine was released by action of the enzyme upon cell wall preparations of several fungi.
Location of the Genes Controlling Alkaline Phosphatase on the F′13 Episome of
Escherichia coli
Authors: Bracha M. , Yagil E.
Published: January 2020

Interrupted mating experiments between F′13 and F
−
cells showed that the location on the F′13 episome of the genes controlling alkaline phosphatase is on the end proximal to the point of entry, in the order
phoA proC phoB phoR tsx
.
Genetic Basis of Nutritional Requirements in
Lactobacillus casei
Authors: Morishita T. , Fukada T. , Shirota M. , Yura T.
Published: January 2020

In a study of the genetic basis of multiple nutritional requirements in
Lactobacillus casei
, systematic attempts were made to isolate mutants that can grow in the absence of a specific nutrient required by the parental organism. Such mutants have successfully been isolated with respect to seven of twelve amino acids (aspartic acid, leucine, isoleucine, lysine, methionine, serine, and threonine) and three of four vitamins (pantothenic acid, nicotinic acid, and pyridoxal) tested, after extensive screenings employing various mutagens. Mutants that can grow without tryptophan were not isolated, but those that can grow on anthranilate or indole as well as on tryptophan were obtained at a frequency expected for single-step mutations. Activity of tryptophan synthetase was demonstrated in extracts of these anthranilate-utilizing mutants, but not in the parental strain. These results suggest that the multiple nutritional requirements of
L. casei
are often, if not always, due to one or a few small lesions such as base substitution mutations rather than large deletions affecting the genes involved in each biosynthetic pathway. The data would also imply that many of the biosynthetic pathways that are not fully functional in
L. casei
were active at one time and became nonfunctional during evolution of the present species.
Asymmetry and Extent of In Vivo Transcripition of R-Plasmid Deoxyribonucleic Acid inEscherichia coli
Authors: Vapnek Daniel , Spingler Elizabeth
Published: January 2020

Deoxyribonucleic acid-ribonucleic acid (DNA-RNA) hybridization studies have been performed with R-plasmid DNA (R538-1drd) and in vivo-synthesized RNA. R-plasmid DNA was isolated fromEscherichia coliK-12, and the complementary strands were separated in cesium chloride-polyuridylic acid-polyguanylic acid gradients. DNA-RNA hybridization was performed with the separated DNA strands and RNA purified from R-plasmid-carrying cells. The results demonstrated that an asymmetric transcription of the R-plasmid DNA occurs in vivo. Hybridization was only detected with the H strand (denser strand in cesium chloride-polyuridylic acid-polyguanylic acid). By determining the density of the RNA-DNA hybrid in CsCl gradients, it was estimated that greater than 60% of the nucleotide sequences in the R-plasmid DNA are transcribed in logarithmically growingE. colicells. No R-plasmid-specific RNA was detected inE. colicells that did not carry the plasmid.
Liberation and Development ofAllomyces arbusculaMitospores Viewed by Scanning Electron Microscopy
Authors: Seale Thomas W. , Delehanty John , Runyan Ray B.
Published: January 2020

Scanning electron microscopy has been employed to examine events in the release and development of mitospores of the aquatic fungus,Allomyces arbuscula. Among the salient features of spore release from the mitosporangium is the digestion of the inner matrix of the exit papillum. Hydrolysis appears to begin at the outer layer of the papillum plug matrix and probably results from activation of localized hydrolytic enzymes. The plug clearly consists of at least two different component layers. Elaboration of mitospores from the mitosporangium is depicted in several micrographs. Motile spores were induced to begin development, and the sequence of surface changes associated with the encystment process was studied. Time course studies show the retraction of the flagellum, the change from elipsoidal to spherical shape, and the deposition of the cell wall. Early in encystment, small vesicles accumulate on the surface of the plasma membrane. These enlarge and fuse to form the mature cyst wall. This surface view of cell wall deposition appears to support the possible role of gamma particles in cell wall synthesis during encystment.
Criteria for categorizing early biochemical events occurring during sporulation of Bacillus subtilis
Authors: Dancer B N , Mandelstam J
Published: January 2020

Two criteria are suggested for assessing the relevance of biochemical events occurring early in sporulation. The first is thymidine starvation, a condition known to inhibit sporulation. This also inhibits the production of metalloprotease, serine protease, and ribonuclease; alpha-amylase production, however, is unaffected. The second is the effect of a regulator mutation which increases the production of the proteases. In the mutant, ribonuclease is produced in correspondingly large quantities whereas alpha-amylase production is unaffected. We conclude that, whereas the serine protease is part of the main sequence of events leading to formation of the spore, the metalloprotease is a side effect, i.e., connected with the main sequence but not part of it. Ribonuclease could, on present evidence, be either in the main sequence or a side effect associated with it. Amylase, however, seems to be separately regulated and neither directly nor indirectly connected with the sporulation sequence.
Circadian rhythms in Neurospora crassa: oscillation in the level of an adenine nucleotide
Authors: Delmer D P , Brody S
Published: January 2020

In a mutant strain (bd) of Neurospora, the biological clock is visibly expressed at the growing front of a mycelial mat by sequential periods of conidiating (spore-forming) and non-conidiating growth. The edges (8 mm) of the mycelium at different ages were sampled during a 31 h period, and the adenine nucleotide levels were enzymatically assayed. In the edge region, the total adenosine 5'-monophosphate (AMP) level showed an oscillation, with a minimum of 0.5 mumol/g (residual dry weight) and a maximum of 6.0 mumol/g. The total adenosine 5'-triphosphate level and the total adenosine 5'-diphosphate level showed no obvious oscillation. The oscillation in AMP content had many of the properties of a circadian rhythm. Its period was about 22 h long, it was phase-shifted by light, and it was damped out by continuous illumination. The oscillation in AMP level led to an oscillation in the overall cellular energy charge from 0.65 to 0.93. However, the energy charge calculation does not take into account any possible compartmentalization of AMP, and therefore must be interpretated cautiously. It is suggested that the underlying cause of the oscillation in AMP level could be a rhythmic, partial uncoupling of mitochondrial oxidative phosphorylation.
Mapping of the fabD locus for fatty acid biosynthesis in Escherichia coli
Authors: Semple K S , Silbert D F
Published: January 2020

fabD mutants of Escherichia coli contain a thermolabile malonyl-coenzyme A-acyl carrier protein transacylase which causes defective fatty acid synthesis and temperature-sensitive growth. By conjugation and P1 transduction the fabD locus has now been mapped at min 24, between pyrC and purB and close to cat. The order of sites is tentatively given as pyrC, cat, fabD, and purB, though the orientation of cat and fabD could be reversed. The possible relationship of fabD with another mutation lying in this region and also affecting acid synthesis is discussed. In the course of these studies we also confirmed the location of the fabA gene, determined that poaA lies between fabA and pyrC, and inadvertently found that the pyr mutation in strain AT3143 is probably pyrF and not pyrC.