bluuebunny/crossref_metadata_2025 huggingface dataset:
d
-Lysine Catabolic Pathway in
Pseudomonas putida:
Interrelations with
l
-Lysine Catabolism
Authors: Chang Yung-Feng , Adams Elijah
Published: January 2020

The isolation of several mutant strains blocked in
l
-lysine degradation has permitted an assessment of the physiological significance of enzymatic reactions related to lysine metabolism in
Pseudomonas putida
. Additional studies with intact cells involved labeling of metabolic intermediates from radioactive
l
- or
d
-lysine, and patterns of enzyme induction in both wild-type and mutant strains. These studies lead to the conclusions that from
l
-lysine, the obligatory pathway is via δ-aminovaleramide, δ-aminovalerate, glutaric semialdehyde, and glutarate, and that no alternative pathways from
l
-lysine exist in our strain. A distinct pathway from
d
-lysine proceeds via Δ
1
-piperideine-2-carboxylate,
l
-pipecolate, and Δ
1
-piperideine-6-carboxylate (α-aminoadipic semialdehyde). The two pathways are independent in the sense that certain mutants, unable to grow on
l
-lysine, grow at wild-type rates of
d
-lysine, utilizing the same intermediates as the wild type, as inferred from labeling studies. This finding implies that lysine racemase in our strain, while detectable in cell extracts, is not physiologically functional in intact cells at a rate that would permit growth of mutants blocked in the
l
-lysine pathway. Pipecolate oxidase, a
d
-lysine-related enzyme, is induced by
d
-lysine and less efficiently by
l
-lysine. Aminooxyacetate virtually abolishes the inducing activity of
l
-lysine for this enzyme, suggesting that lysine racemase, although functionally inactive for growth purposes, may still have regulatory significance in permitting cross-induction of
d
-lysine-related enzymes by
l
-lysine, and vice versa. This finding suggests a mechanism in bacteria for maintaining regulatory patterns in pathways that may have lost their capacity to support growth. In addition, enzymatic studies are reported which implicate Δ
1
-piperideine-2-carboxylate reductase as an early step in the
d
-lysine pathway.
Biochemical Localization of Alkaline Phosphatase in the Cell Wall of a Marine Pseudomonad
Authors: Thompson Linda M. M. , MacLeod Robert A
Published: January 2020

The various layers of the cell envelope of marine pseudomonad B-16 (ATCC 19855) have been separated from the cells and assayed directly for alkaline phosphatase activity under conditions established previously to be optimum for maintenance of the activity of the enzyme. Under conditions known to lead to the release of the contents of the periplasmic space from the cells, over 90% of the alkaline phosphatase was released into the medium. Neither the loosely bound outer layer nor the outer double-track layer (cell wall membrane) showed significant activity. A small amount of the alkaline phosphatase activity of the cells remained associated with the mureinoplasts when the outer layers of the cell wall were removed. Upon treatment of the mureinoplasts with lysozyme, some alkaline phosphatase was released into the medium and some remained with the protoplasts formed. Cells washed and suspended in 0.5 M NaCl were lysed by treatment with 2% toluene, and 95% of the alkaline phosphatase in the cells was released into the medium. Cells washed and suspended in complete salts solution (0.3 M NaCl, 0.05 M MgSO
4
, and 0.01 M KCl) or 0.05 M MgSO
4
appeared intact after treatment with toluene but lost 50 and 10%, respectively, of their alkaline phosphatase. The results suggest that the presence of Mg
2+
in the cell wall is necessary to prevent disruption of the cells by toluene and may also be required to prevent the release of alkaline phosphatase by toluene when disruption of the cells by toluene does not take place.
Distribution of Purple Photosynthetic Bacteria in Wetland and Woodland Habitats of Central and Northern Minnesota
Authors: Burke Mary E. , Gorham Eville , Pratt Douglas C.
Published: January 2020

Enrichment cultures for purple nonsulfur and sulfur photosynthetic bacteria were prepared from soil samples collected in central and northern Minnesota. The purple nonsulfur bacteria were found in most wetland soils sampled but were uncommon in woodland and grassland soils. The pH range of the soils in which these bacteria occurred was 3.8 to 7.8, and the oxidation-reduction potential (
E
h
) range was +510 to −65 mV. Soils with a pH below 5.0 or an
E
h
above +370 mV had few purple nonsulfur bacteria (<10/g of soil).
Rhodopseudomonas viridis
, a photosynthetic bacterium containing bacteriochlorophyll
b
, and the purple sulfur bacteria were common only in low-acidity wetland soils that were usually being reduced.
Orientation of Membrane Vesicles from
Escherichia coli
as Detected by Freeze-Cleave Electron Microscopy
Authors: Altendorf K. H. , Staehelin L. A.
Published: January 2020

The application of freeze-cleave electron microscopy to whole cells of
Escherichia coli
revealed that the particles exposed on the resulting two inner membrane faces are asymmetrically distributed. This method can therefore be used to determine the orientation of membrane vesicles from
E. coli
. Membrane vesicles freshly prepared in potassium phosphate buffer (K
+
-vesicles) by osmotic lysis of spheroplasts consisted almost entirely of right-side-out vesicles. Their size suggested that each cell gives rise to one vesicle. When the membrane vesicles were subjected to one cycle of freezing and thawing, the number of inside-out vesicles rose to about 25%. However, due to the small size of most of the inside-out vesicles, these contribute only 2 to 3% of the total membrane surface area of the preparation. The inside-out vesicles appear to arise from infoldings of the membrane of right-side-out vesicles. They also accumulate within the latter, thus producing multivesicular membrane sacs. Na
+
-vesicles (vesicles prepared in sodium phosphate buffer) subjected to freezing and thawing appeared to lose structural rigidity more than did K
+
-vesicles. In contrast to the membrane vesicles prepared by the osmotic lysis of spheroplasts, those obtained by breaking intact cells by a single passage through a French pressure cell were uniformly very small (only 40 to 110 nm in diameter); approximately 60 to 80% were inside-out. To reconcile the polarity of the membrane vesicles with the enzymic activities of such preparations, we propose that “dislocation” of membrane proteins occurs during osmotic lysis of spheroplasts.
Effect of Photoreactivation on the Filling of Gaps in Deoxyribonucleic Acid Synthesized After Exposure of
Escherichia coli
to Ultraviolet Light
Authors: Bridges B. A. , Sedgwick S. G.
Published: January 2020

Daughter-strand gaps in deoxyribonucleic acid (DNA) synthesized after exposure of excision-deficient
Escherichia coli
to ultraviolet light are filled during subsequent incubation in buffer, and the rate of filling is increased when the incubation in buffer is carried out in the presence of 360-nm light. It is concluded that daughter-strand discontinuities are prevented from being rapidly sealed in the dark not because of some structural feature of the daughter-strand but because of the presence of a pyrimidine dimer on the opposite (parental) strand. “Photoreactivation-stimulated gap filling” is dependent on the
polA
+
and
recA
+
but not the
exrA
+
genes. It is suggested that the removal of the dimer allows gap-filling by DNA polymerase I and polynucleotide ligase. The
recA
+
gene may be needed at a very early stage, possibly for gap stabilization.
Genetic Analysis of Cold-Sensitive Ribosome Maturation Mutants of
Escherichia coli
Authors: Bryant Robert E. , Sypherd Paul S.
Published: January 2020

Four cold-sensitive mutants of
Escherichia coli
, which have defects in the maturation of the 50
S
ribosomal subunit, were isolated. Each of the mutations was shown to map at a different locus. The loci were assigned the name
rim
(ribosome maturation) and were shown to map as follows:
rimA
is co-transduced with
ilvD
and with
pyrE; rimB
is co-transduced with
aroD;
conjugation experiments limited
rimD
to a region between
ilv
and
malB
, and conjugation experiments limited
rimC
to the 22 to 30 min region of the chromosome. In merodiploids heterozygous for
rimA, rimB
, or
rimD
, the wild-type allele was shown to be dominant to the mutant allele. The observation that the
rim
loci lie outside the
strA
region and separate from each other, as well as the recessive character of the
rim
loci, suggests that the mutants may be defective in ribosome maturation factors rather than being defective in ribosomal structural proteins.
Regulation of Aconitase Synthesis in
Bacillus subtilis
: Induction, Feedback Repression, and Catabolite Repression
Authors: Ohné Margareta
Published: January 2020

The synthesis of aconitase in
Bacillus subtilis
wild-type and different citric acid cycle mutants has been studied and the influence of various growth conditions examined. Aconitase is induced by citrate and precursors of citrate and repressed by glutamate. Induction and repression counteract each other, and at equimolar concentrations of citrate and glutamate, aconitase synthesis is unaffected. Induction by citrate can partly overcome catabolite repression of aconitase. Isocitrate dehydrogenase show endogenous induction of aconitase due to citrate accumulation. Leaky mutants defective in citrate synthase and aconitase cannot be induced by citrate, which indicates that they carry a regulatory mutation. The complex regulation of aconitase is discussed with reference to the participation of this enzyme in glutamate biosynthesis and energy metabolism.
Degradation of Thymidine by
Lactobacillus acidophilus
Authors: Sawula R. V. , Zamenhof S. , Zamenhof P. J.
Published: January 2020

Whole cells of
Lactobacillus acidophilus
are capable of degrading thymidine to thymine, suggesting the presence of thymidine phosphorylase (or thymidine hydrolase). This activity was also demonstrated in cell-free extracts.
Reversion of Frameshift Mutations by Mutator Genes in
Escherichia coli
Authors: Siegel Eli C. , Kamel Freja
Published: January 2020

The
Escherichia coli
mutator genes
mutU4, mutS3
, and
mut-25
(a possible allele of
mutL
), previously known to induce transitional base changes, increased significantly the frequencies of reversion of
lacZ
frameshift mutations.
mutT1
, previously shown to induce only the transversion of adenine-thymine to cytosine-guanine, had no effect on the reversion of
lacZ
frameshift mutations. With mutator genes other than
mutT1
, small increases were found in the frequencies of reversion of
trpA
frameshift mutations.
Separation of the Polypeptides of
Chlamydia
and Its Cell Walls by Polyacrylamide Gel Electrophoresis
Authors: Tamura Akira , Tanaka Akiko , Manire G. P.
Published: January 2020

The polypeptide composition of
Chlamydia
was examined by acrylamide gel electrophoresis. When the polypeptide patterns of purified infectious elementary bodies (EB) of
C. psittaci
meningopneumonitis strain, 6BC strain, and
C. trachomatis
T'ang strain were compared, no significant differences were observed. The polypeptide patterns of whole EB and reticulate bodies (RB) appeared to overlap, but differences were found. In EB cell walls, nine main and several minor bands of polypeptides were observed in gels containing sodium lauryl sulfate, and the eighth main band from the top of the gel stained positive with periodic acid-Schiff reagent. On the other hand, the polypeptides in bands 3, 6, and 8 in EB cell walls were missing or minor in RB cell walls, and the ninth band was clearly stained by PAS. Band 8 was also stained slightly. Purified subunits, which occur as a lattice structure on the inside layer of EB cell walls but are largely missing in RB cell walls, contained bands 4, 6, and 8, and band 8 was PAS positive. These results indicate that significant polypeptide synthesis or reorganization in the cell walls occurs during the growth cycle.
Subunit Cell Wall of
Sulfolobus acidocaldarius
Authors: Weiss Richard L.
Published: January 2020

The cell wall of
Sulfolobus acidocaldarius
has been isolated. Cells were mechanically disrupted with a French press, and the cytoplasmic membrane was removed by extracting cell-envelope fragments with Triton X-100. The Triton-insoluble cell wall material retained the characteristic subunit structure when examined in the electron microscope. Isolated cell wall fragments formed in open sheets that were easily separated from cytoplasmic contamination. Chemical studies showed that the Triton-insoluble cell wall fragments consisted of lipoprotein with small amounts of carbohydrate and hexosamine. The amino acid composition indicated a highly charged hydrophobic cell surface. The presence of diaminopimelic acid with only traces of muramic acid indicates that the cell envelope does not have a rigid peptidoglycan layer. The results of chemical analyses and electron microscopy suggest a wall-membrane interaction stabilizing the cell envelope. The chemical and physical properties of this type of cell envelope would appear to form the basis for a new major division of bacteria with the definitive characteristics of a morphologically distinct subunit cell wall devoid of peptidoglycan.
Studies on
l
-Serine Deaminase in
Escherichia coli
K-12
Authors: Isenberg S. , Newman E. B.
Published: January 2020

l
-Serine deaminase has been studied in toluene-treated cells of
Escherichia coli
K-12 and shown to be a discrete entity distinct from
l
-threonine deaminase. Its level in the cell varies as a function of nitrogen nutrition, carbon source, and amino acids (glycine and leucine). The metabolic role of the enzyme remains unclear but may be related to serine toxicity. The enzyme is unstable within the cell in the presence of its inducers, glycine and leucine, but not in their absence.
Localization of Proteinase(s) near the Cell Surface of
Streptococcus lactis
Authors: Thomas T. D. , Jarvis B. D. W. , Skipper N. A.
Published: January 2020

Two criteria suggest that most of the proteinase of
Streptococcus lactis
is localized in the cell wall. (i) Intact cells possess proteinase activity when incubated with a high-molecular-weight substrate. (ii) Most of the cell-bound proteinase activity is released during spheroplast formation under conditions which result in the release of only 1% of the intracellular enzymes aldolase and glyceraldehyde-3-phosphate dehydrogenase. The solubilized cell wall, plasma membrane, and cytoplasm fractions contained 84, 0, and 16%, respectively, of the total proteinase activity with casein as substrate. The physiological role of a surface-bound proteinase in this organism is discussed.
Role of the
leu-3
Cistron in the Regulation of the Synthesis of Isoleucine and Valine Biosynthetic Enzymes of
Neurospora
Authors: Olshan Arthur R. , Gross S. R.
Published: January 2020

The production by
Neurospora
of the enzymes of isoleucine and valine synthesis in response to specific end product-derived signals depends upon the presence of an effective
leu-3
regulatory product and its effector α-isopropylmalate (α-IPM). In
leu-3
+
strains, threonine deaminase production is repressed as a function of available isoleucine, acetohydroxy acid synthetase as a function of valine, and the isomeroreductase and dihydroxy acid dehydratase as a function of isoleucine and leucine. In the absence of an effective
leu-3
regulatory product, α-isopropylmalate, or both, the production of isoleucine and valine biosynthetic enzymes is fixed at or near fully repressed levels even under conditions of severe end product limitation. Thus, in addition to its involvement in the regulation of expression of the three structural genes of leucine synthesis, the
leu-3
α-IPM regulatory product is necessary for full expression of at least four genes specifying the structure of the enzymes of isoleucine and valine synthesis. It is suggested that the
leu-3
α-IPM regulatory element may facilitate transcription of the genetically dispersed cistrons either by imposing specificity on ribonucleic acid polymerase for structurally similar promoters adjacent to each of the cistrons or by “opening” promoters after interaction with nearly identical stretches of deoxyribonucleic acid near each of the structural genes.
Properties of α-Aminoisobutyric Acid Transport in a Thermophilic Microorganism
Authors: Reizer Jonathan , Grossowicz Nathan
Published: January 2020

Uptake of α-aminoisobutyric acid (AIB) by a leucine-tyrosine auxotroph of a thermophilic microorganism starved for leucine was studied. AIB was taken up by the cells against a substantial concentration gradient (300:1) and was present there in a free and unchanged form. Various energy inhibitors and sulfhydryl reagents strongly inhibited the accumulation of AIB. AIB uptake obeyed saturation kinetics, and the Lineweaver-Burk plot is characterized by a biphasic curve. AIB most probably shares a common transport system(s) with alanine, serine, and glycine. A mutant defective inl-alanine uptake was isolated by using the suicide effect due to accumulation of the tritiated substrate. The mutant also exhibited impaired transport activity towards AIB, glycine, andl-serine, but not to phenylalanine or valine. The transport of AIB, glycine,l-alanine, andl-serine was induced byd-alanine (5 × 10−3M) during growth in a succinate- and ammonia-containing medium. De novo protein synthesis was required for the induction of AIB transport; the induction was inhibited when growth occurred in glucose-containing media. The apparent differential rate of synthesis of the AIB transport system was decreased considerably in glucose-grown cells as compared to succinate-grown cells. A common genetic basis of either the regulatory or structural nature for the transport of AIB, alanine, glycine, and serine in a thermophilic microorganism is suggested.
Explanation for the Apparent Inefficiency of Reduced Nicotinamide Adenine Dinucleotide in Energizing Amino Acid Transport in Membrane Vesicles
Authors: Hampton M. L. , Freese E.
Published: January 2020

Lineweaver-Burk plots of reduced nicotinamide adenine dinucleotide (NADH) oxidation by membrane preparations from
Bacillus subtilis
are biphasic, with two

K
m

values for NADH. The higher

K
m

corresponds to the only

K
m

observed for NADH oxidation by whole cells, whereas the lower

K
m

corresponds to that observed with open cell envelopes. Membrane preparations apparently contain a small fraction of open or inverted vesicles which is responsible for the low

K
m

reaction, whereas entry of NADH into the larger portion of closed, normally oriented vesicles is rate limiting and responsible for the high

K
m

reaction. In contrast, the oxidation of
l
-α-glycerol-phosphate (glycerol-P) by membrane preparations shows only one

K
m

that corresponds to that of glycerol-P oxidation by whole cells or lysates. Since glycerol-P dehydrogenase (NAD independent) has the same

K
m

, this enzyme reaction rather than entry of glycerol-P into vesicles represents the rate-limiting step for glycerol-phosphate oxidation. The

K
m

for amino acid uptake by vesicles in the presence of NADH corresponds to the high

K
m

for NADH oxidation, indicating that NADH energizes transport only if it enters closed, normally oriented vesicles. Studies with rotenone and proteolytic enzymes support this interpretation. The apparent efficiency of NADH in energizing uptake seems to be lower than that of glycerol-P because, under the experimental conditions usually employed, open or inverted vesicles that do not participate in amino acid uptake are responsible for the major portion of NADH oxidation. When the results are corrected for this effect, the efficiency of NADH is essentially the same as that of
l
-α-glycerol-P.
Effects of Oxygen Tension and Glucose Repression on Mitochondrial Protein Synthesis in Continuous Cultures of
Saccharomyces cerevisiae
Authors: Rogers P. J. , Yue S. B. , Stewart P. R.
Published: January 2020

Continuous cultures of
Saccharomyces cerevisiae
grown over a range of oxygen and glucose concentrations were used to determine the effects of these two physiological regulators on mitochondrial protein synthesis in vivo. Quantitative estimates were obtained of the contribution of the mitochondrial protein-synthesizing system to the formation of mitochondrial membranes in cells grown over a wide range of dissolved oxygen concentrations, under conditions of glucose limitation or glucose excess in the cultures. The nature of the products of the mitochondrial system formed under these conditions was examined by selectively labeling membrane proteins in vivo in the presence of cycloheximide, and fractionating the products by gel electrophoresis under dissociating conditions. These results have been correlated with changes in the lipid composition of the cells and with the synthesis and assembly of components of the mitochondrial adenosine 5′-triphosphatase complex.
Mutants of
Escherichia coli
Defective in Membrane Phospholipid Synthesis: Mapping of the Structural Gene for
l
-Glycerol 3-Phosphate Dehydrogenase
Authors: Cronan John E. , Bell Robert M.
Published: January 2020

The structural gene for the biosynthetic
l
-glycerol 3-phosphate dehydrogenase has been mapped at min 71.5 on the
Escherichia coli
chromosome. This gene (
gpsA
) is co-transduced with the
xyl, mtl
, and
pyrE
loci. Three-factor conjugational crosses and the transduction data indicate that the order of loci in this region of the chromosone is
mtl, gltE, gpsA, gadR, gadS, pyrE
. Study of a temperature-sensitive
gpsA
mutant possessing a dehydrogenase of increased thermolability indicated that
gpsA
is the structural gene for the dehydrogenase. All dehydrogenase-deficient strains tested were mapped very close to the
gpsA
locus. Attempts at genetic complementation analysis were unsuccessful.
Polyelectrolyte Nature of Bacterial Teichoic Acids
Authors: Doyle R. J. , McDannel M. L. , Streips U. N. , Birdsell D. C. , Young F. E.
Published: January 2020

Several physicochemical properties of the teichoic acid ofBacillus subtilis168 have been determined. The teichoic acid partial specific volume was found to be 0.57 ml/g. The apparent weight-average molecular weight of the polymer was 24,800. Sedimentation was strongly dependent on solvent. The sedimentation coefficient of the teichoic acid was found to have a value ofs20.w0= 1.90S. In dilute buffers and distilled water, the teichoic acid possessed a rigid rod or extended conformation. Salts induced a loss of secondary structure in the polymer, resulting in a random coil configuration. Salt-induced structural changes in the teichoic acid were determined by viscosities, ultraviolet difference spectra, and inhibition of precipitation with concanavalin A. Divalent cations such as Mg2+had little effect on the teichoic acid structure. The salt-induced structural changes were reversible, as evidenced by return of the original properties upon dialysis of the teichoic acid against water. Sodium chloride inhibited the adsorption of bacteriophage ø25 toB. subtiliscell walls. Teichoic acid conformation may have a significant influence on the physiology of bacteria.
Location of the Fracture Faces Within the Cell Envelope of
Acinetobacter
Species Strain MJT/F5/5
Authors: Sleytr U. B. , Thornley Margaret J. , Glauert Audrey M.
Published: January 2020

The cell wall of the gram-negative bacterium
Acinetobacter
species strain MJT/F5/5 shows in thin section an external “additional” layer, an outer membrane, an intermediate layer, and a dense layer. Negatively stained preparations showed that the additional layer is composed of hexagonally arranged subunits. In glycerol-treated preparations, freeze-etching revealed that the cell walls consist of four layers, with the main plane of fracture between layers cw 2 and cw 3. The surface of [Formula: see text] 2 consisted of densely packed particles, whereas [Formula: see text] 3 appeared to be fibrillar. In cell envelopes treated with lysozyme by various methods, the removal of the dense layer has detached the outer membrane and additional layer from the underlying layers, as shown in thin sections. When freeze-etched in the absence of glycerol, these detached outer membranes with additional layers fractured to reveal both the faces [Formula: see text] 2 and [Formula: see text] 3 with their characteristic surface structures, and, in addition, both the external and internal etched surfaces were revealed. This experiment provided conclusive evidence that the main fracture plane in the cell wall lies within the interior of the outer membrane. This and other evidence showed that the corresponding layers in thin sections and freeze-etched preparations are: the additional layer, cw 1; the outer membrane, cw (2 + 3); and the intermediate and dense layers together from cw 4. Because of similarities in structure between this
Acinetobacter
and other gram-negative bacteria, it seemed probable that the interior of the outer membrane is the plane most liable to fracture in the cell walls of most gram-negative bacteria.
Autolytic Formation of Protoplasts (Autoplasts) of
Streptococcus faecalis
9790: Release of Cell Wall, Autolysin, and Formation of Stable Autoplasts
Authors: Joseph R. , Shockman G. D.
Published: January 2020

A system for the formation of apparently wall-free protoplasts from exponential-phase cells of
Streptococcus faecalis
ATCC 9790 in the absence of added lytic enzymes was developed. Exponential-phase cells suspended in 0.04 M ammonium acetate, pH 6.7, 1 mM magnesium acetate, and 0.5 M sucrose become osmotically fragile within 1 to 1.5 h due to the action of the native, autolytic enzyme on the cell wall peptidoglycan. However, maximal cell wall loss occurred much more slowly, being complete only after 3 to 6 h. Under these conditions, the autolytically formed protoplasts (autoplasts) remained intact for prolonged periods (up to 24 h) with less than 5% of their deoxyribonucleic acid, ribonucleic acid, and protein lost during the first 6 h. During dissolution of the cell wall, release of autolytic enzyme to the supernatant fluid began after 60% of the wall was lost. The addition of trypsin to the incubation mixture increased the rate of attainment of osmotic fragility and cell wall loss two- to threefold, apparently due to the activation of the latent form of the autolysin. Electron microscopy was used to confirm cell wall loss and the presence of intact protoplasts at the end of the incubation periods.
5-Keto-d-Fructose: Formation and Utilization in the Course ofd-Fructose Assimilation byGluconabacter cerinus
Authors: Mowshowitz Solomon , Avigad Gad , Englard Sasha
Published: January 2020

The accumulation of 5-keto-d-fructose (5KF) byGluconobacter cerinusgrown ond-fructose in unbuffered medium was shown to be optimal at pH 4.0 after cell growth ceased. During the exponential phase of growth or at neutral pH after the onset of the stationary phase, 5KF production continued but did not accumulate because of its rapid reutilization by reduction tod-fructose. The extent of isotope incorporation into C5 of ribonucleic acid ribose when cells were grown in the presence of specifically labeledd-glucose andd-fructose clearly indicated that (i) the hexose monophosphate oxidative pathway is the predominant metabolic route for carbohydrate assimilation and (ii) extensive randomization of label between C1 and C6 ofd-fructose occurred prior to its conversion into pentose. It is suggested that the cyclic oxidation and reduction through the symmetrical 5KF molecule, which accounts for the observed randomization of isotope ind-fructose, provides the cells with an effective mechanism for the regeneration of nicotinamide adenine dinucleotide phosphate during the period of intensive growth.
Genetic Studies on Ribose 5-Phosphate Isomerase Mutants of
Escherichia coli
K-12
Authors: Skinner A. J. , Cooper R. A.
Published: January 2020

A gene for the constitutive ribosephosphate isomerase (
rpiA
) is highly cotransducible with
serA
at 56.2 min on the genetic linkage map of
Escherichia coli
K-12. Suppression of ribosephosphate isomerase A-negative mutants can occur by a regulator gene mutation permitting constitutive synthesis of the normally inducible ribosephosphate isomerase B.
Microbial Water Relations: Features of the Intracellular Composition of Sugar-Tolerant Yeasts
Authors: Brown A. D.
Published: January 2020

Several factors contributed to differences in intracellular composition between sugar-tolerant (osmophilic) and nontolerant species of yeast. One such factor was the difference in accumulation of those nonelectrolytes whose uptake was not dominated by vigorous metabolism. In such cases (lactose and glycerol), the sugar-tolerant species had a much lower capacity for the solute than did the nontolerant species. Sucrose uptake was consistently different between all sugar-tolerant strains on the one hand and all nontolerant strains on the other. The difference was attributable in part to metabolism of sucrose by the nontolerant yeasts. The major difference between the two types of yeast, however, was the presence of one or more polyhydric alcohols at high concentrations within each of the sugar-tolerant strains but none of the nontolerant strains. In most cases the major polyol was arabitol. The solute concentration (and, hence, water availability) of the growth medium affected both the amount of arabitol produced by
Saccharomyces rouxii
and the proportion retained by the yeast after brief washing with water at 0 C. When the yeast was suspended in a buffer at 30 C, the polyol leaked out at a slow, constant, reproducible rate. The polyene antibiotic amphotericin B caused rapid release of polyol by the yeast, the rate being proportional to amphotericin concentration. Contact of the yeast with glucose (1 mM) caused an extremely rapid ejection of polyol which lasted less than 40 s. Some implications of these results are discussed, as is the role of the polyol as a compatible solute in determining the water relations of the yeast.
Acceleration of Dextransucrase Activity ofStreptococcus mutansby Secretory Immunoglobulin A
Authors: Fukui Kazuhiro , Fukui Yoshio , Moriyama Takafumi
Published: January 2020

The effect of immunoglobulins on the activity of dextransucrase purified fromStreptococcus mutansstrain HS-6 is described. When human salivary immunoglobulin A (IgA) or colostral IgA, either natured or denatured, was incubated with dextransucrase, the rate of the dextran synthesis was markedly accelerated, whereas human serum IgA or IgG neither accelerated nor inhibited the enzyme activity. The results suggest that a portion unique for secretory IgA, the secretory component, might be related to the enzyme acceleration. On the other hand, specific rabbit antiserum against the dextransucrase inhibited completely dextran synthesis by the enzyme.
Effect of Preirradiation Ribonucleic Acid Synthesis Inhibition on Resistance to Ultraviolet Light with Resistant and Sensitive Strains of
Escherichia coli
B/r
Authors: Rudé J. M. , Doudney C. O.
Published: January 2020

The ultraviolet resistance of a streptolydigin-susceptible strain of
Escherichia coli
B/r
hcr
−
increased during preirradiation treatment with streptolydigin (an inhibitor of deoxyribonucleic acid-dependent ribonucleic acid polymerase) for 20 min and then remained constant. During preirradiation treatment with chloramphenicol (an inhibitor of protein synthesis), resistance to ultraviolet light increased for 1 to 2 h, and reached a maximal level significantly above that attained in streptolydigin-containing medium. These results suggest that there are two mechanisms that function in Hcr
−
cells during chloramphenicol treatment which contribute to the concomitant ultraviolet resistance enhancement. One is ribonucleic acid dependent and is inhibited by streptolydigin. This ribonucleic acid-dependent mechanism appears to be absent in wild-type and RecA
E. coli
B/r strains.
Effect of Dicyclohexylcarbodiimide on Growth and Membrane-Mediated Processes in Wild Type and Heptose-Deficient Mutants of
Escherichia coli
K-12
Authors: Singh A. P. , Bragg P. D.
Published: January 2020

The effects of
N,N
′-dicyclohexylcarbodiimide (DCCD) on the growth of
Streptococcus faecalis
, and on the growth, β-galactosidase synthesis, and various membrane-mediated processes, were studied in wild-type
Escherichia coli
JE1011 and its lipopolysaccharide-defective mutant NS1. DCCD (0.1 mM) completely inhibited the growth of
S. faecalis
and
E. coli
NS1 but had little effect on strain JE1011. The same amount of DCCD with
E. coli
NS1, but not with
E. coli
JE1011, inhibited the induction of β-galactosidase, increased the permeability of the cells to
o
-nitrophenyl-β-
d
-galactoside without causing extensive cell lysis or release of ultraviolet-absorbing materials, and inhibited the oxidation of certain intermediates of the tricarboxylic acid cycle. Inhibition of the oxidation of malate, fumarate, and α-ketoglutarate by DCCD appeared to be at the level of the transport system for these compounds. Inhibition of the membrane-bound adenosine triphosphatase by DCCD was not entirely responsible for these effects, since oxidation of these substances, and transport of [
14
C]succinate and [
14
C]fumarate, was inhibited by DCCD in a mutant, N
144
, which lacked adenosine triphosphatase activity. It is concluded that lipopolysaccharide forms a barrier to DCCD in wild-type
E. coli
, and that DCCD can inhibit several processes in the cell.
Interference of Griseofulvin with the Segregation of Chromosomes at Mitosis in Diploid
Aspergillus nidulans
Authors: Kappas A. , Georgopoulos S. G.
Published: January 2020

Low concentrations of the antibiotic griseofulvin were found to cause increased frequencies of somatic segregation due to chromosome nondisjunction in a diploid strain of
Aspergillus nidulans
.
Inhibition of Replication Gap Closure in
Escherichia coli
by Near-Ultraviolet Light Photoproducts of
l
-Tryptophan
Authors: Yoakum G. , Ferron W. , Eisenstark A. , Webb R. B.
Published: January 2020

Near-ultraviolet photoproducts of
l
-tryptophan (TP) differentially inhibited deoxyribonucleic acid (DNA) replication in wild-type cells and
uvrA, polA1
, and
recA recB
double mutants of
Escherichia coli
. Wild-type cells labeled in their DNA with [
3
H]thymidine in the presence of TP produced small pieces of DNA (7 × 10
6
daltons), which corresponded in size to late replicative intermediates of discontinuous DNA synthesis. Moreover, when TP was present, it took five times longer to chase the low-molecular-weight DNA pieces into high-molecular-weight DNA. The observation of replicative intermediates in the presence of TP, and their slow chase into high-molecular-weight DNA in the presence of TP, is strong evidence that TP stabilizes replication gaps in
E. coli
DNA. Although TP slowed DNA replication in wild-type cells, this effect was transient and DNA synthesis eventually resumed at a normal rate. However, in
polA1
and
recA recB
mutants, DNA synthesis was completely inhibited. Determinations of size and total counts of cells incubated in TP suggested that TP uncouples cell division from DNA replication in
recA recB
mutants, whereas these processes remain coupled in wild-type cells and in
uvrA
and
polA1
mutants. The slow chase of TP-stabilized pieces of DNA in the presence of TP suggested that the selective effect of TP on DNA synthesis and viability in repair-deficient mutants is a result of TP inhibition of replication gap closure.
Regulation of Neutral Protease Productivity inBacillus subtilis: Transformation of High Protease Productivity
Authors: Uehara Hiroshi , Yoneda Yuko , Yamane Kunio , Maruo Bunji
Published: January 2020

A transformable strain ofBacillus subtilis6160, a derivative ofB. subtilis168, produces three kinds of casein hydrolytic enzymes (alkaline protease, neutral protease, and esterase) in a culture medium.B. nattoIAM 1212 produces 15 to 20 times as much total proteolytic activity as doesB. subtilis. Extracellular proteases produced by the two strains were separated into each enzyme fraction by diethylaminoethyl-Sephadex A-50 column chromatography. The difference in the total protease activities of extracellular proteases between the two strains was due to the amount of neutral protease. The ratios of neutral protease activity to alkaline protease activity (N/A) were 1.1 inB. subtilis6160 and 13.0 inB. nattoIAM 1212. Enzymological and immunological properties of alkaline protease and neutral protease obtained from the two strains were quite similar or identical, respectively. Specific activities measured by an immunological analysis of the two neutral proteases against casein were also equal. A genetic character of high protease productivity inB. nattoIAM 1212 was transferred toB. subtilis6160 by the deoxyribonucleic acid-mediated transformation. Among 73 transformants that acquired high protease productivity, 69 produced a higher amount of neutral protease and the ratios of N/A were changed to 15 to 60. Three other strains were transformed in the productivity of neutral protease and α-amylase simultaneously, and one showed considerable change in the production of alkaline protease and neutral protease. The specific activities (casein hydrolytic activities/enzyme molecules) of neutral proteases from the representative four transformants were equal to those of the two parental strains. These results suggested the presence of a specific gene(s) that participated in the productivity of neutral protease inB. subtilis.
Glycerol Metabolism in
Bacillus subtilis
: Gene-Enzyme Relationships
Authors: Lindgren Viveka , Rutberg Lars
Published: January 2020

Bacillus subtilis
mutants unable to catabolize glycerol (Glp mutants) were isolated and mapped. The location of the mutations on the chromosome was determined by a density transfer technique and confirmed by PBS1 transduction and transformation. The different mutations were ordered relative to each other. Mutations rendering the cells glycerol auxotrophic were also mapped and found not to be linked to the Glp mutations.
Reversal of Flagellar Rotation in Monotrichous and Peritrichous Bacteria: Generation of Changes in Direction
Authors: Taylor Barry L. , Koshland D. E.
Published: January 2020

Reversal of flagellar rotation can explain both the “backing up” of monoflagellated
Pseudomonas citronellolis
and the tumbling of multiflagellated
Salmonella typhimurium
. Reversals occur spontaneously and can be induced by negative gradients of attractant and by high-intensity light.
Fatty Acids Present in the Lipopolysaccharide of
Rhizobium trifolii
Authors: Russa R. , Lorkiewicz Z.
Published: January 2020

Approximately 70% of the fatty acids recovered after acid or alkaline hydrolysis of the lipopolysaccharide of
Rhizobium trifolii
were hydroxy fatty acids identified as hydroxymyristic and hydroxypalmitic acids. Palmitic acid was the only saturated fatty acid found in the lipopolysaccharide of
R. trifolii
. Octadecenoic and a small amount of hexadecenoic acids were also identified. The results of BF
3
methanolysis and hydroxylaminolysis suggest that hydroxypalmitic acid is
N
-acyl bound.
Physiological Roles of Pneumococcal Peptidases
Authors: Johnson Mary K.
Published: January 2020

A methionyl-specific dipeptidase from
Streptococcus pneumoniae
has been described. This enzyme and the pneumococcal tripeptidase have been shown to be intracellular, soluble, and constitutive. In addition to their function in cleavage of peptide nutrients, these peptidases may play a role in protein synthesis and turnover.
Purification and Propeties of (+)-
cis
-Naphthalene Dihydrodiol Dehydrogenase of
Pseudomonas putida
Authors: Patel T. R. , Gibson D. T.
Published: January 2020

Cells of
Pseudomonas putida
, after growth with naphthalene as sole source of carbon and energy, contain an enzyme that oxidizes (+)-
cis
-1(
r
),2(
s
)-dihydroxy-1,2-dihydronaphthalene to 1,2-dihydroxynaphthalene. The purified enzyme has a molecular weight of 102,000 and apparently consists of four 25,500 molecular weight subunits. The enzyme is specific for nicotinamide adenine dinucleotide as an electron acceptor and also oxidizes several other
cis
-dihydrodiols. However, no enzymatic activity was observed with
trans
-1,2-dihydronaphthalene, or the K-region
cis
-dihydrodiols of carcinogenic polycyclic hydrocarbons.
Protein Synthesis in Relation to Sporulation and Meiosis in Yeast
Authors: Magee P. T. , Hopper Anita K.
Published: January 2020

The dependence upon protein synthesis of physiological and biochemical events occurring during yeast sporulation was investigated. Protein synthesis was inhibited by cycloheximide. There was an early, irreversible sensitivity to inhibition with respect to cell viability and ascus formation; inhibition was reversible only if the cells were inhibited after, but not prior to, 2 to 3 h in sporulation medium. Interruption of protein synthesis of any time during sporulation inhibited all measurable metabolic and sporulation-specific processes except protein breakdown and, to some extent, ribonucleic acid synthesis. The time interval between the occurrence of an event and the protein synthesis necessary for that event was determined to be 2 to 3 h for ascus formation, ≤30 min for deoxyribonucleic acid synthesis, 1 h for tetranucleate cell formation, ≤30 min for ribonucleic acid breakdown, 1 to 2 h for glycogen synthesis, and 2 to 3 h for glycogen breakdown.
Relationship Between the Membrane Envelope of Rhizobial Bacteroids and the Plasma Membrane of the Host Cell as Demonstrated by Histochemical Localization of Adenyl Cyclase
Authors: Tu J. C.
Published: January 2020

By using adenyl cyclase as a marker enzyme, the relationship between the membrane envelope of the bacteroids of rhizobia and the plasma membrane of the host cell was demonstrated histochemically. Electron-dense deposits were found on the outer surface of the plasma membrane of the host cell and on the inner surface of the membrane envelopes of the bacteroids, but not in vacuole membranes, endoplasmic reticula, Golgi apparatus, and mitochondrial membranes. The results suggest that the membrane envelopes of the bacteroids are closely related to the host plasma membrane, and that entry of the bacteroids into the cytoplasm is in a manner similar to endocytosis.
Adenosine 3′,5′-Cyclic Monophosphate-Deficient Mutants of
Vibrio cholerae
Authors: Yokota Takeshi , Kuwahara Shogo
Published: January 2020

Two adenosine 3′,5′-cyclic monophosphate (AMP)-deficient mutants of
Vibrio cholerae
(biotype El Tor) were successfully isolated by nitrosoguanidine treatment followed by pencillin screening for pleiotropic sugar-negative clones. Exogenous cyclic AMP is required for the fermentation of sucrose, trehalose, fructose, maltose, and mannose but not of glucose, as well as for the formation of normal flagella and specific somatic antigens. A striking characteristic of the mutants is their growth behavior at higher temperatures. They cannot grow on TCBS selective plates at 37 C or higher unless they are provided with a supply of exogenous cyclic AMP, although they are capable of producing colonies on the same medium, even without cyclic AMP, at temperatures lower than 30 C. Since the mutants are converted to spheroplasts, spindle forms, and spiral filaments in cyclic AMP-free media at 37 C, and this phenomenon is stopped by the addition of cyclic AMP or a combination of 20% sucrose and 0.2% magnesium chloride, it is assumed that cyclic AMP is essential for the synthesis of the cell wall of
V. cholerae
at higher temperatures.
Effect of Sodium on the Transport and Utilization of Citric Acid by
Aerobacter
(
Enterobacter
)
aerogenes
Authors: Wilkerson L. S. , Eagon R. G.
Published: January 2020

Sodium inhibited citrate uptake by two of the four strains of
Aerobacter
(
Enterobacter
)
aerogenes
used in these studies, had no effect on one strain, and stimulated citrate uptake by one strain. Two of the four strains grew well anaerobically on citrate in the presence of Na
+
, one grew poorly, and one grew not at all either in the presence or absence of Na
+
. Na
+
stimulated the aerobic growth of one strain on citrate, increased the total growth but not the rate of growth of one strain, and prolonged the lag phase but not the rate of growth or total growth of two strains. The experimental data reported herein, therefore, indicate that there are appreciable physiological differences among strains of
A. aerogenes
.
Plasmid Specificity of The Origin of Transfer of Sex Factor F
Authors: Reeves Peter , Willetts Neil
Published: January 2020

The ability of F-like plasmids to promote transfer from the F origin of transfer was determined. Chromosome transfer was measured from plasmid derivatives of RecA
−
Hfr deletion strains which had lost all the F transfer genes but which in some cases retained, and in others had also lost, the origin sequence. ColV2 and ColVB
trp
could initiate transfer from the F origin, but R100-1, R1-19, and R538-1
drd
could not. These results can be correlated with the plasmid specificity of the
traI
components of the different plasmid transfer systems, supporting the hypothesis that the origin of transfer is the site of action of the
traI
product. Most F-like plasmids, including R1-19 and R538-1
drd
, could transfer ColE1, consistent with previous findings that the (plasmid-specific)
traI
product is not necessary for ColE1 transfer by F
lac;
ColE1 transfer may be initiated by a ColE1-or host-determined product. R100-1 and R136
fin
−
could not transfer ColE1 efficiently, apparently because of differences residing in their pilus-forming genes.
Preliminary Analysis of Lipids and Fatty Acids of Green Bacteria and
Chloroflexus aurantiacus
Authors: Kenyon Christine N. , Gray Alane M.
Published: January 2020

The complex lipids and fatty acids of the seven type species of green bacteria and three strains of
Chloroflexus aurantiacus
were analyzed. The green bacteria contained lipids that behaved as cardiolipin and phosphatidylglycerol on thin-layer chromatography. They did not contain phosphatidylethanolamine or phosphatidylserine. Similarly,
Chloroflexus
contained lipids that behaved as phosphatidylglycerol and phosphatidylinositol on thin-layer chromatography and did not contain phosphatidylethanolamine or phosphatidylserine. The green bacteria contained glycolipids I and II of Constantopoulos and Bloch (monogalactosyldiglyceride and a galactose- and rhamnose-containing diglyceride).
Chloroflexus
exhibited galactose-containing glycolipids that behaved identically with the mono- and digalactosyldiglycerides of spinach on thin-layer chromatography, and each contained galactose as well as at least one other sugar. The fatty acids of both groups of bacteria consisted entirely of saturated and monounsaturated fatty acids. In the green bacteria, myristic, palmitic, and hexadecenoic acids predominated. In
Chloroflexus
, palmitic, stearic, and oleic acids predominated. The positions of the double bonds in the monounsaturated fatty acids of
Chloroflexus
indicated synthesis by the anaerobic pathway. The lipid analyses suggest a close relationship between the green bacteria and
Chloroflexus
and further suggest that these groups of photosynthetic bacteria are more closely related to the blue-green algae than are the purple bacteria.
Glucose Uptake and Phosphorylation in
Pseudomonas fluorescens
Authors: Eisenberg R. C. , Butters S. J. , Quay S. C. , Friedman S. B.
Published: January 2020

Pseudomonas fluorescens
ATCC 13525 and a particulate glucose oxidase (
d
-glucose:oxygen oxidoreductase, EC 1.1.3.4) mutant of this organism, gox-7, were examined to determine if glucose oxidation via particulate glucose oxidase is a required first step for glucose uptake. Initial [
14
C]glucose-uptake rates in parent and gox-7 cells were qualitatively similar. Initial [
14
C]glucose-uptake product analysis revealed that glucose was accumulated via active transport and was rapidly metabolized to glucose-6-phosphate and gluconate-6-phosphate in both parent and gox-7 cells. Cell extracts contained soluble adenosine 5′-triphosphate specific kinase activity for phosphorylation of glucose. Glucose uptake was induced by glucose and not gluconate, thus, establishing independent regulation of glucose transport and glucose catabolism in
p. fluorescens
. The results prove that glucose oxidase was not an obligatory reaction for glucose carbon permeation in
P. fluorescens
. A general unifying scheme for glucose utilization in the aerobic fluorescent pseudomonads is suggested for the purpose of clarifying glucose uptake in these bacteria.