bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunochemical and Enzymatic Comparisons of the Tryptophan Synthase α Subunits from Five Species ofEnterobacteriaceae
Authors: Murphy T. M. , Mills S. E.
Published: January 2020

The reactive surface structures of α subunits of tryptophan synthase fromEscherichia coli, Shigella dysenteriae, Salmonella typhimurium, Aerobacter aerogenes, andSerratia marcescenswere compared by measuring (i) their reactivities in micro-complement-fixation assays with antibodies directed specifically toE. coliwild-type α subunit, (ii) their reactivities in enzyme neutralization assays with the same antibodies, and (iii) their binding affinities for tryptophan synthase β2subunits. The enzymes from the four heterologous species cross-reacted in the microcomplement-fixation assays with the anti-E. coliα subunit antibodies, each to a different degree. However, neutralization titers of the antibodies reacting with the various α subunits were comparatively similar, and the β2subunit-binding and -stimulating abilities of the α subunits were even more closely alike. The results suggested that the tertiary structure of the β2subunit-binding site of the α subunit has been conserved, relative to the rest of the molecule, during the evolutionary divergence of the species ofEnterobacteriaceae.
Sialidase-like Enzymes Produced by Group A, B, C, G, and L Streptococci and by
Streptococcus sanguis
Authors: Hayano Seiki , Tanaka Atsuko
Published: January 2020

A group of enzymes were prepared from the culture fluids of streptococci belonging to groups A, B, C, G, and L, and from a strain of
Streptococcus sanguis
. These streptococcal enzymes (designated St-sialidases) released a substance shown to belong to the sialic acid group from the specific substrate BSM-St, a sialomucoid prepared from bovine submaxillary gland. They were inactive on
N
-acetylneuramin lactose prepared from bovine colustrum and on a sialomucoid prepared from bovine submaxillary mucin, whereas these substances are susceptible to sialidases produced by group K streptococci and by
Vibrio cholerae
. Some of the St-sialidases were markedly activated by divalent cations, but others showed little response. The heat stability of the enzymes produced by the different strains varied. The optimal
p
H was between 5.5 and 6.5 with acetate buffer and was about 7 with phosphate buffer.
K
m
values were determined for the St-sialidases with BSM-St as substrate.
Mutant of
Escherichia coli
with Anomalous Cell Division and Ability to Decrease Episomally and Chromosomally Mediated Resistance to Ampicillin and Several Other Antibiotics
Authors: Normark Staffan , Boman Hans G. , Matsson Eva
Published: January 2020

In a mutation experiment with a rough, ampicillin-resistant strain, we isolated two smooth mutants which were both sensitive to ampicillin and carried defects in the cell envelope. One of the strains (with the
envA
gene) is hindered in its completion of septa and forms chains of cells. The
envA
gene has been mapped to a position between
leu
and
proB
, at 2 to 4 min. The
envA
gene decreased the resistance mediated by both episomal and chromosomal genes for resistance to several antibiotics. During growth the
envA
mutant was characterized by abnormal ratios between viable count or cell count and optical density. The ratio between viable count and optical density was affected during shift-up and shift-down experiments. When compared to the parent strain, the
envA
mutant was found to be more resistant to ultraviolet irradiation on plates. Prestarvation for tryptophan had a protective effect against irradiation both on the parent strain and the
envA
mutant.
Escherichia coli
Mutant with Elevated Nicotinamide Adenine Dinucleotide Phosphate (Reduced) Oxidase Activity
Authors: Corwin Laurence M. , Fanning G. Richard
Published: January 2020

A slow-growing mutant of
Escherichia coli
with greatly elevated nicotinamide adenine dinucleotide phosphate (reduced; NADPH) oxidase activity has been isolated. The oxidase activity of the wild-type organism, normally low at
p
H 7.5, was increased when the assay was performed at
p
H 6.0. Sucrose density gradients of sonic extracts of the mutant and wild-type strains revealed several peaks of NADPH oxidase activity at
p
H 6.0. The parent organism had a peak of activity of high molecular weight which was absent from the mutant. The mutant strain had an activator capable of increasing the activity of all wild-type density gradient peaks, especially the one of high molecular weight. The activator was either missing or masked in the wild type. Agar gel electrophoresis of the extracts uncovered a rapidly moving band from the wild type, missing from the mutant; the material in this band had weak NADPH-diaphorase activity and strongly inhibited the activity of the mutant NADPH oxidase. It was concluded that, in wild-type
E. coli
, NADPH oxidase activity is regulated by a proper balance of an activator and an inhibitor. The absence of the inhibitor, as in the mutant, or the inactivation of the inhibitor at acid
p
H levels, results in a high level of NADPH oxidase activity. The relation of high NADPH oxidase levels and subsequent decrease of the NADPH pool to the decrease in growth rate is considered.
Changes in the Ultraviolet Sensitivity of
Escherichia coli
During Growth in Batch Cultures
Authors: Morton R. A. , Haynes R. H.
Published: January 2020

The ultraviolet (UV) sensitivity of
Escherichia coli
B/r harvested at various times during growth in batch cultures was measured. The results showed a period of increased UV sensitivity in late log phase, just before the cultures entered stationary phase. This increase in sensitivity was associated with a decreased shoulder in the UV survival curves. The postirradiation division delay of survivors was shortest for cells harvested during the period of maximal sensitivity. This period of increased UV sensitivity during late log phase was not found in the radiation-sensitive, repair-deficient mutant B
s−1
(a strain which is unable to excise pyrimidine dimers from UV-damaged deoxyribonucleic acid). These results suggest that the variation in UV sensitivity of
E. coli
B/r as a function of time of harvesting of the cells from batch cultures is related to the varying capacities of these populations to repair UV-damaged deoxyribonucleic acid. Further experiments designed to elucidate the mechanism underlying this variation in UV sensitivity indicated that it arises from the partial depletion of nutrients in the medium during late log phase. We suggest that growth in such depleted media leads to a depression in the intercellular concentration or activity of one or more of the repair enzymes concerned with the repair of damaged deoxyribonucleic acid.
2-Deoxyribose Gene-Enzyme Complex in
Salmonella typhimurium
: Regulation of Phosphodeoxyribomutase
Authors: Hoffee Patricia A. , Robertson B. C.
Published: January 2020

Phosphodeoxyribomutase, the enzyme which catalyzes the interconversion of 2-deoxyribose-1-phosphate to 2-deoxyribose-5-phosphate, has been partially purified from
Salmonella typhimurium
. The enzyme had an absolute requirement for manganese ion and was stimulated by glucose-1, 6-diphosphate. Phosphodeoxyribomutase was induced by deoxyribose-5-phosphate and was coordinately regulated with the enzymes thymidine phosphorylase and deoxyribose-5-phosphate aldolase, type II. Mutants deficient in these three enzymes were isolated and mapped close to the threonine locus in
S. typhimurium
. The three enzymes thymidine phosphorylase, deoxyribose-5-phosphate aldolase, type II, and phosphodeoxyribomutase are controlled by a series of linked genes and appear to constitute an operon.
Characterization of Pyridoxine Auxotrophs of
Escherichia coli
: P1 Transduction
Authors: Dempsey Walter B.
Published: January 2020

Pyridoxine mutants of
Escherichia coli
B, previously divided into a minimum of six groups by cross-feeding tests, were characterized by transduction studies performed with phage P1bt. The results of these studies allowed division of pyridoxine mutants into five unlinked groups and set the minimum number of enzymes between pyridoxal phosphate and a metabolite common to other pathways at six or seven, with the probable maximum at ten. One group was shown to be linked to
thr, leu
, and
pyrA
.
Characterization of Polynucleotide Phosphorylase Mutants ofEscherichia coli
Authors: Reiner Albey M.
Published: January 2020

Three polynucleotide phosphorylase mutations, isolated in heavily mutagenizedEscherichia colistrains Q7, Q13, and Q27, were characterized after their transfer by P1 transduction to nearly isogenic strains which lack ribonuclease I. Each strain has a different altered form of polynucleotide phosphorylase. One enzyme exhibited sharply reduced activity under all conditions tested. A second had reduced activity which was stimulated by Mn++. The third enzyme was thermolabile and could be >95% inactivated in vivo at 44 C andpH 6 if the cells were prevented from growing; during growth under these and other conditions, the full enzyme level was maintained. The strains showed no differences from the wild type in their growth rates, their adjustments to changes in media and temperature, or their recoveries from starvation.
Effect of Enzymes on the Composition and Structure of
Chromobacterium violaceum
Cell Envelopes
Authors: Whiteside Theresa L. , Corpe W. A.
Published: January 2020

Cell envelopes of
Chromobacterium violaceum
were isolated and treated under controlled conditions with trypsin, Pronase, lipase, phospholipase C, lysozyme, and a mixture of enzymes produced by a bacteriolytic
Pseudomonas
sp. After each enzyme treatment, losses in dry weight, protein, lipid, carbohydrate, 2,6-diaminopimelic acid, and total phosphorus were determined. Electron-microscopic examination of the enzyme-treated envelopes indicated complete or partial loss of envelope rigidity or some envelope fragmentation, or both. Each enzyme hydrolyzed at least one envelope component and liberated several others into the supernatant fluid, where they appeared as nondialyzable particulate components, identified by means of electron microscopy. Unlike the other enzymes, the
Pseudomonas
sp. enzyme mixture partially liberated all major envelope components except phosphorus, heptose, and 2-keto-3-deoxy octonic acid. In spite of these large losses, the envelopes preserved some features of their integrity and elongated shape.
Molar Growth Yield of
Streptococcus faecalis
on Pyruvate
Authors: Moustafa Hassan H. , Collins E. B.
Published: January 2020

Y(pyruvate) was 17.3, similar to Y(arginine), for
Streptococcus faecalis
6783 grown statically in a complex medium in 1 atm of air.
Physiological and Biochemical Changes in Bacterial Cells Exposed to Oxygen
Authors: Young Ho Lee
Published: January 2020

Pure oxygen at 1 atm exerts two opposite effects on
Pseudomonas saccharophila
: it inhibits sucrose uptake and lipid synthesis, but it enhances the formation of polysaccharides.
Selective Media for the Detection of Revertants in Cultures of Glycogen-deficient Mutants
Authors: Chester V. E. , Byrne M. J.
Published: January 2020

Glycogen-deficient yeast mutants grew more slowly than wild-type cells on certain nonfermentable carbon substrates. Revertant colonies could be detected on these lines.
Phospholipids of
Azotobacter vinelandii
Authors: Jurtshuk Peter , Schlech Barry A.
Published: January 2020

Analyses of resting cells of
Azotobacter vinelandii
revealed that numerous phospholipids were present that did not concentrate in the membranous R
3
fraction which carried out electron transport function.
Genetic and Physiological Analysis of Glutamate Decarboxylase in
Escherichia coli
K-12
Authors: Marcus Menashe , Halpern Yeheskel S.
Published: January 2020

No correlation was found between glutamate decarboxylase (GAD) activity and the ability of
Escherichia coli
K-12 strains to grow on glutamate. A gene,
gad
, determining GAD activity maps near
gltC
, which controls glutamate permease.
Demonstration of a Bactericidal Substance Against β-Hemolytic Streptococci in Supernatant Fluids of Staphylococcal Cultures
Authors: Dajani Adnan S. , Wannamaker Lewis W.
Published: January 2020

Staphylococcal skin isolates belonging to phage type 71 were found to produce a bactericidal substance against some streptococci, pneumococci, and corynebacteria. Fifteen strains of group A streptococci belonging to 13 different M types, group C streptococci, and group D streptococci were uniformly inhibited on solid media and in broth by membrane-filtered supernatant fluids of the staphylococcal broth cultures. Inhibition of group G streptococci and other staphyloccoci was variable, and no inhibition of group B streptococci or of a variety of gram-negative rods was demonstrable. A quantitative variation observed to exist among susceptible organisms was a function of the inoculum size of the inhibited strains. The bactericidal substance could be detected best from 24 to 48 hr after inoculation of the staphylococci in tryptic soy broth or in a dialysate of tryptic soy broth. Little or no bactericidal activity was noted when the organisms were grown in several other liquid media. The bactericidal substance was nondialyzable and could be precipitated with ammonium sulfate. It was heat-stable and its activity was not altered within apH range of 4.0 to 8.5. Pronase and three times crystallized trypsin totally abolished its activity. The concentrated ammonium sulfate precipitate could be fractionated on a Sephadex G-100 column into several peaks, with the bactericidal activity localized to a single peak.
Intermediate Energy Metabolism of
Leptospira
Authors: Baseman J. B. , Cox C. D.
Published: January 2020

Metabolic studies were performed on three representative serotypes of
Leptospira
: a water isolate designated B
16
and two pathogenic serotypes,
pomona
and
schueffneri
. Examination of whole cells of B
16
for their ability to oxidize various substrates revealed that oleate significantly stimulated oxygen uptake. The respiratory quotient of 0.7 implied that oleate was degraded to carbon dioxide and water. Other substrates, such as carbohydrates, alcohols, intermediates of the citric acid cycle, and short-chain acids, including selected amino acids, did not stimulate endogenous respiration of whole cells. No oxygen uptake could be measured when cell-free extracts were tested with the substrates used with whole cells. Enzymatic analyses of cell-free extracts of the three strains demonstrated enzymes of the citric acid cycle, enzymes of the glycolytic and pentose pathways, and the general acyl coenzyme A dehydrogenase required for β-oxidation of fatty acids. Strain B
16
and the two pathogenic serotypes appeared to possess similar metabolic capabilities. Enzymatic data might also explain the apparent inability of B
16
to oxidize other substrates; kinases necessary for activation of common nonphosphorylated compounds were not detected in leptospiral extracts. These findings emphasized the dependence of leptospiral growth upon long-chain fatty acids.
Enzymes of Tryptophan Biosynthesis in
Serratia marcescens
Authors: Hutchinson M. A. , Belser W. L.
Published: January 2020

In
Serratia marcescens
, the tryptophan biosynthetic enzymes were formed coordinately. A number of tryptophan auxotrophs showed single biochemical lesions; several mutants showed pleiotropic effects. Sucrose density gradient centrifugation revealed an unique pattern of migration of the tryptophan biosynthetic enzymes. The repression response of the
Serratia
enzymes to exogenous tryptophan was fivefold more sensitive than that found in
Escherichia coli
. When this information is contrasted with the available information on the other
Enterobacteriaceae
, one is compelled to conclude that
S. marcescens
enjoys a rather marked evolutionary divergence from the other enteric organisms.
Chemical Constituents and Hydrogenase Binding in Cell Envelopes of
Vibrio succinogenes
Authors: Niederman R. A. , Wolin M. J.
Published: January 2020

The particulate hydrogenase of
Vibrio succinogenes
is solubilized during treatment of cell envelopes at
p
H 11.0. Alkali-solubilized enzyme requires sulfhydryl compounds for activity. At neutral
p
H, soluble enzyme is reincorporated into alkalitreated cell envelopes and no longer requires an additional activator. In the present study, cell envelopes prepared by lysing cells with ethylenediaminetetraacetic acid plus lysozyme (EDTA-lysozyme) were used to determine the chemical composition of cell envelopes and derived
p
H 11.0 soluble and insoluble fractions and to investigate some properties of the binding and activation of alkali-solubilized hydrogenase. Lysis with EDTA-lysozyme resulted in the formation of spheroplast ghosts. The derived cell envelopes contained 61% protein, 3% ash, 23% lipid, and 1% phosphorus. The alkali-treated cell envelopes contained 50% protein, 2% ash, 24% lipid, and 1% phosphorus. The ash from cell envelopes and alkali-treated cell envelopes was rich in iron and phosphorus and also contained calcium, copper, magnesium, sodium, and zinc. Virtually all of the weight of the ashed samples was accounted for by the oxides of these metals. Since the reconstitution of particulate hydrogenase was achieved with
p
H 11.0 supernatant solution and precipitate, intact mucopeptide is not essential for hydrogenase binding. Release of hydrogenase during EDTA-lysozyme lysis was found to depend upon an apparent structural change which occurs in the membranes during extended storage at −20 C.
N-Acetylation of Glucosamine-6-Phosphate in Leuconostoc mesenteroides
Authors: DeMoss R. D. , Moser K.
Published: January 2020

A partially purified enzyme (120-fold) from
Leuconostoc mesenteroides
catalyzed the reversible
N
-acetylation of
d
-glucosamine-6-phosphate. Coenzyme A was not required and inhibited the reaction rate. Neither
d
-glucosamine nor
N
-acetyl-
d
-glucosamine served as a substrate for the reversible reaction. The enzyme preparation retained 50% of its original activity after 5 min at 100 C. The
K
m
for acetate was 7.7 × 10
−2
m
in the presence of 2 × 10
−2
m
d
-glucosamine-6-phosphate. The
K
m
for
d
-glucosamine-6-phosphate was 5.0 × 10
−3
m
in the presence of 0.64
m
acetate. The product of the reaction was characterized by comparison with
N
-acetyl-
d
-glucosamine-6-phosphate prepared by enzymatic phosphorylation of
N
-acetyl-
d
-glusamine. The characterization tests were: chromatographic migration, acid hydrolysis, enzymatic dephosphorylation, sodium borohydride reduction, and periodate oxidation. The equilibrium constant for the reaction was about 7.5
m
for the expression
K
= (
d
-glucosamine-6-phosphate)(acetate)/
N
-acetyl-
d
-glucosamine-6-phosphate. The standard free energy of the reaction was approximately 1,200 cal per mole.
d
-Tyrosine as a Metabolic Inhibitor of
Bacillus subtilis
Authors: Champney W. Scott , Jensen Roy A.
Published: January 2020

The
d
-isomer of tyrosine is a potent inhibitor of growth in transformable strain 168 of
Bacillus subtilis
. A
d
-tyrosine-resistant mutant of the inhibited strain was isolated which excreted
l
-tyrosine, had a diminished growth rate, and required
l
-phenylalanine to attain the growth rate of the wild-type parent. Mapping by deoxyribonucleate transformation located this resistance in the gene coding for prephenate dehydrogenase. This enzyme in the
d
-tyrosine-resistant mutant was insensitive to the usual feedback inhibition exerted by
l
-tyrosine in extracts of strain 168. In contrast, the growth of poorly transformable strain 23 of
B. subtilis
, as well as that of several other
Bacillus
species, was not affected by the analogue. Transformation mapping demonstrated no linkage of this latter “natural resistance” to several different aromatic markers. Prephenate dehydrogenase in extracts from strain 23 was as sensitive as that from strain 168 to feedback inhibition by
l
-tyrosine in vitro. The relationships of the latter results to the regulation of tyrosine biosynthesis and the possible nature of strain differences in
d
-tyrosine sensitivity are discussed.
Naturally Occurring Penicillinase Plasmids in
Staphylococcus aureus
Authors: Peyru Graciela , Wexler Laura Fooner , Novick Richard P.
Published: January 2020

A series of plasmids harbored by naturally occurring penicillin-resistant strains of
Staphylococcus aureus
were surveyed with a view toward exploring the variability in plasmid-linked marker patterns. Plasmids were transduced from their natural hosts to either of two plasmid-negative laboratory strains by selection for cadmium resistance, and the transductants were tested for all other markers previously found to be plasmid-linked. All of the strains that were able to serve as genetic donors to one of the two stock strains could donate cadmium and lead resistance as linked, plasmid-borne markers. Among the other plasmid markers, a wide variety of patterns was found, including four plasmids that did not carry the penicillinase determinant. Each of the 26 plasmids studied, including the latter 4, was found to belong to one of the two incompatibility sets of penicillinase plasmids previously identified. With the exception of the penicillinase-negative plasmids, which were found in both sets, all the plasmids of incompatibility set I directed the production of penicillinase type A; those belonging to set II directed either type A or type C. Those of set II without exception increased the sensitivity of their host strains to bismuth ion; those of set I carried determinants of bismuth resistance or did not affect the sensitivity of their host to this ion. No other perfect correlations between markers were encountered; in particular, there was no correlation between penicillinase serotype and the excretion of the enzyme. This finding allows the prediction that there is, in addition to all of the markers thus far identified, a plasmid-linked determinant of penicillinase excretion.
Relationship Between Glucose Utilization and Growth Rate in
Bacillus subtilis
Authors: Baschnagel-DePamphilis J. , Hanson R. S.
Published: January 2020

The effect of growth rate on the rate of glucose utilization has been examined with a sporogenic and a weakly sporogenic strain of
Bacillus subtilis
by means of the continuous culture technique. Cultures were grown aerobically on a mineral salts medium with glucose as the carbon and energy source. During both nitrogen and
l
-tryptophan limitation, the rate of glucose consumption (milligrams of glucose per hour per milligrams of cells) decreased when the growth rate was decreased. The coupling between the rate of glucose disappearance and the growth rate was estimated as 76 to 86% during nitrogen limitation and as 60 to 78% during tryptophan limitation. Sporulation had no detectable influence on the coupling.
Effect of Decreasing Growth Temperature on Cell Yield of
Escherichia coli
Authors: Ng Henry
Published: January 2020

Studies of the relationship between yield coefficient and growth rate, as affected by temperature of growth, in
Escherichia coli
have shown that, over a wide range of temperature, yield is relatively constant until the specific growth rate falls below about 0.2 hr
−1
, at which point the yield begins to fall off precipitously. No intermediates of glucose metabolism in a form utilizable at higher temperatures could be found in the medium, and no toxic product was produced which limited growth. At 10 C, 37% of the carbon from glucose-
UL
-
14
C
was assimilated into cellular material, whereas, at 30 C, 53% was assimilated. Cells grown at 10 C contained more carbohydrate than did cells grown at 37 C, and the glycogen-to-protein ratio of cells grown at 10 C was approximately three times higher than that of cells grown at 37 C. Adenosine triphosphatase activities of cells grown at 10 and 35 C were similar. Growth rates on glucose, glycerol, and succinate were quite similar at 10 C, but at 35 C growth was most rapid on glucose and slowest on succinate. The data suggest that the decrease in yield with decrease in temperature is a result of uncoupling of energy production from energy utilization.
Effect of Lysozyme on Resting Spores of
Bacillus Megaterium
Authors: Suzuki Yahiko , Rode L. J.
Published: January 2020

Resting spores of
Bacillus megaterium
ATCC 9885 were found to be markedly affected by lysozyme. Exposure to as little as 1.5 μg of lysozyme per ml caused the spores to lose refractility, the darkened spores to shed their coat structures, and the spore central bodies to lyse. The spores of seven other strains of
B. megaterium
and seven other
Bacillus
species were not similarly affected by lysozyme. Proteolytic enzymes such as pronase, trypsin, pepsin, and subtilisin did not induce the change. The action of lysozyme differed in certain important respects from that of common “physiological” germinants. Its action was considered to be direct via its enzymatic attack on exposed sites directly accessible in the resting spores of
B. megaterium
ATCC 9885.
Purification, Ultrastructure, and Composition of Axial Filaments from
Leptospira
Authors: Nauman Robert K. , Holt Stanley C. , Cox C. D.
Published: January 2020

The ultrastructure of three strains of water
Leptospira
was studied by negative staining, thin sectioning, and freeze-etching. The cells possessed a triple-layered sheath which covered two independent axial filaments, one inserted subterminally in each end of the cell. The protoplasmic cylinder was surrounded by a triple-layered cell wall and possessed ribosomes, lamellar structures, and a typical procaryotic nuclear region. The axial filament was comprised of several component structures. An axial fibril, with a diameter of 20 to 25 nm, consisted of a solid inner core (13 to 16 nm in diameter) surrounded by a coat. A terminal knob (40 to 70 nm in length) was connected to a series of disc insertion structures at the terminal end of the axial fibril. The axial fibril was surrounded by a helical outer coat (35 to 60 nm in diameter) which was composed of a continuously coiled fiber, 3 to 4 nm in diameter, embedded in an electron-dense material. A procedure for the purification of the axial fibrils was presented and their ultrastructural, physical, and chemical properties were determined. Similarities in ultrastructural, physical, and chemical properties were noted between the axial fibrils and bacterial flagella. A schematic model of the leptospiral axial filament is presented, and a mechanism is proposed for its function as a locomotor organelle.
Relation of In Vitro Inhibition by Chelates ofClostridium perfringensα-Toxin to Their Ability to Protect Against Experimental Toxemia
Authors: Senff Leah M. M. , Moskowitz Merwin
Published: January 2020

The inhibition ofClostridium perfringensα-toxin by ethylenediaminetetraacetate (EDTA) and diethylenetriaminepentacetate (DTPA) was studied utilizing three different in vitro assay procedures: diffusion on egg yolk-agar, disintegration of muscle sections, and manometric assay with partially purified lecithin as substrate. DTPA was 10 to 20 times more efficient as an inhibitor than EDTA in systems containing relatively large amounts ofcalcium; these observations were similar to those observed in previous in vivo protection studies. A number of other chelating agents were tested for their ability to inhibit α-toxin in vitro and protect mice against it; the chelating agents which were the most efficient in vitro inhibitors had the greatest in vivo protective ability.
Hydrogenation of Linoleic Acid by a Rumen Spirochete
Authors: Sachan D. S. , Davis C. L.
Published: January 2020

Borrelia
sp. B
2
5, when grown in a medium containing [1-
14
C] linoleic acid in an atmosphere of CO
2
, was found to hydrogenate linoleic acid to
trans
-11-octadecenoic acid.
Amino Acid Composition of Ferredoxin and Rubredoxin Isolated from
Desulfovibrio gigas
Authors: Laishley E. J. , Travis J. , Peck H. D.
Published: January 2020

The composition of ferredoxin and rubredoxin from
Desulfovibrio gigas
was determined. Ferrodoxin contained five cysteines, two methionines, and four irons. The rubredoxin was not unique.
Restoration by Ubiquinone of
Azotobacter vinelandii
Reduced Nicotinamide Adenine Dinucleotide Oxidase Activity
Authors: Swank R. T. , Burris R. H.
Published: January 2020

Extraction with pentane virtually abolished reduced nicotinamide adenine dinucleotide oxidase activity in small particles from
Azotobacter vinelandii
, but activity was largely restored by added ubiquinone.
Locus Determining P1 Phage Restriction in
Escherichia coli
Authors: Wu Tai Te
Published: January 2020

The locus determining P1 phage restriction has been mapped at 89.3 min on the
Escherichia coli
map, about 0.2 min away from the hsp marker.
Uptake and Distribution of Labeled Carbon from
14
C-Asparagine by
Mycobacterium tuberculosis
Authors: Lyon Richard H. , Hall Wendell H. , Costas-Martinez Carlos
Published: January 2020

Asparagine supplies not only nitrogen but also carbon to growing cells of
Myobacterium tuberculosis
. The carbon of asparagine is rapidly taken up and extensively utilized.
Deoxyribonucleic Acid Homology Among the Fruiting Myxobacteria
Authors: Johnson John L. , Ordal Erling J.
Published: January 2020

Deoxyribonucleic acid similarities were determined by competition experiments. The several strains of fruiting myxobacteria tested showed from 23 to 89% homology with the reference strains
Myxococcus xanthus
(FB) and
M. fulvus
(M6).
Complementary Functioning of Two Components from Nitrogen-fixing Bacteria
Authors: Dahlen Jeanne V. , Parejko R. A. , Wilson P. W.
Published: January 2020

Use of alternate substrates (acetylene, azide, cyanide) for estimating N
2
fixation confirmed that recombined fractions from different bacteria are functional but restricted in complementarity.
Influence of the Fertility Episome on the Survival of X-irradiated
Escherichia coli
Authors: Axelrod D. E. , Adler H. I.
Published: January 2020

The resistance of
Escherichia coli
to the lethal effects of X rays was increased by the presence of a fertility episome integrated into the chromosome.
Regulation of Staphylococcal Enterotoxin B
Authors: Morse Stephen A. , Mah Robert A. , Dobrogosz Walter J.
Published: January 2020

Several factors influenced the formation of enterotoxin B by
Staphylococcus aureus
strain S-6. In the standard casein hydrolysate medium, toxin was not produced in detectable quantities during exponential growth; it was produced during the post-exponential phase when total protein synthesis was arithmetic. The rate of toxin synthesis was much greater than the rate of total protein synthesis. The appearance of enterotoxin was inhibited by chloramphenicol; thus, the presence of toxin was dependent on de novo protein synthesis. When low concentrations of glucose (<0.30%) were added to the casein hydrolysate medium, growth was diauxic; glucose was completely metabolized during the first growth period. During the second growth period, enterotoxin was synthesized. In unbuffered casein hydrolysate medium containing excess glucose, toxin synthesis was completely repressed. The absence of toxin production under such conditions might be explained by the low (4.6)
p
H resulting from the acid end products of glucose metabolism. At
p
H <5.0, little or no toxin was produced. Toxin synthesis was initiated in the presence of glucose when the medium were buffered at any
p
H above 5.6. In such media, the differential rates of toxin synthesis, with respect to the rates of total protein synthesis, were lower than the differential rates in casein hydrolysate medium alone. Addition of glucose to a culture synthesizing toxin resulted in an immediate decrease in the differential rate without any change in
p
H. Thus, toxin synthesis appeared to be regulated by catabolite repression.
Hydrogenase Measurement with Photochemically Reduced Methyl Viologen
Authors: Yu L. , Wolin M. J.
Published: January 2020

Methyl viologen was reduced photochemically in the presence of proflavine and ethylenediaminetetraacetic acid. The reduced methyl viologen was oxidized by hydrogenase from
Vibrio succinogenes
. H
2
and oxidized methyl viologen were the products. Hydrogenase activity was determined by spectrophotometric measurement of the disappearance of reduced methyl viologen at 600 nm. The extinction coefficient of reduced methyl viologen was determined and is 8.25 m
m
−1
× cm
−1
at 600 nm. Optimal conditions for assaying
V. succinogenes
hydrogenase were developed. Extracts of
Escherichia coli
and
Desulfovibrio desulfuricans
catalyzed reduced methyl viologen oxidation in the assay system, whereas
Azotobacter vinelandii
extracts were inactive.
Biochemical Studies of Bacterial Sporulation and Germination XIII. Adenylate Kinase of Vegetative Cells and Spores of
Bacillus subtilis
Authors: Spudich James A. , Kornberg Arthur
Published: January 2020

The spore and vegetative cell adenylate kinases of
Bacillus subtilis
, purified about 1,000-fold, proved indistinguishable by several physical and functional tests, including polyacrylamide gel electrophoresis, DEAE cellulose chromatography, and specificity toward substrates. Adenylate kinase activity in cell extracts, followed throughout growth and sporulation, was found to reach a maximum near the end of exponential growth, remain at that level during sporulation, until shortly before the appearance of refractile forms, and then decline, along with total protein, during the subsequent maturation of the spores. The enzyme, stable in extracts of exponential growing cells, was unstable in extracts of sporulating cells, presumably as a result of degradation by protease(s) appearing after the end of exponential growth.
Effect of Nalidixic Acid on Deoxyribonucleic Acid Synthesis in Bacteriophage SPO1-infected
Bacillus subtilis
Authors: Gage L. Patrick , Fujita Donald J.
Published: January 2020

The effect of nalidixic acid on deoxyribonucleic acid (DNA) synthesis in
Bacillus subtilis
cells infected with bacteriophage SPO1 was studied. Nalidixic acid had little inhibitory effect on SPO1 DNA synthesis at concentrations that drastically inhibited
B. subtilis
DNA synthesis. Inhibition of DNA synthesis, appropriate to the concentration used, was imposed within 1 min after addition of nalidixic acid, suggesting that it acts directly on DNA synthesis in both infected and uninfected cells. The SPO1 DNA synthesized in the presence of high concentrations of nalidixic acid had a density characteristic of normal SPO1 DNA and was packaged into viable progeny phage particles, but its rate of synthesis was reduced and bacterial lysis was delayed.
Plasmolysis ofEscherichia coliB/r with Sucrose
Authors: Scheie Paul O.
Published: January 2020

Escherichia coliB/r cells were plasmolyzed in sucrose solutions and observed under phase contrast. The prevalence of plasmolysis under various conditions was noted, and the degree of plasmolysis was categorized as slight, extensive, or severe. The presence of ions reduced the prevalence of plasmolysis. Survival curves showed that extensive plasmolysis was not lethal to colony-forming ability.
Dextran-induced Agglutination of
Streptococcus mutans
, and Its Potential Role in the Formation of Microbial Dental Plaques
Authors: Gibbons R. J. , Fitzgerald R. J.
Published: January 2020

Glucose-grown washed cells of streptococci similar to
Streptococcus mutans
, which contain cell-bound dextransucrase, have been observed to agglutinate upon the addition of high molecular weight dextran. Low molecular weight dextran or unrelated polysaccharides were ineffective. Agglutination also occurred upon addition of sucrose, which can be converted into dextran, but not with other mono- and disaccharides. Other bacteria, including species capable of synthesizing dextrans, were not observed to exhibit this phenomenon. Cells of
S. mutans
agglutinated upon addition of dextran over a wide
p
H range, but maximal sensitivity to dextran occurred at
p
H 8.5. At this
p
H, such cells can be used for a simple, specific, and exquisitely sensitive qualitative assay for high molecular weight dextran, for addition of 6 ng of dextran with a molecular weight of 2 × 10
6
(i.e., approximately three molecules per cell) caused detectable agglutination. High concentrations of glucose, levan, and dextran of molecular weight of 2 × 10
4
inhibited the reaction. Fluorescein-labeled cells of
S. mutans
were observed to adhere to dextran-containing plaques and dextran-treated teeth, suggesting that this phenomenon may be of importance in the formation of streptococcal dental plaques. The mechanism responsible for dextraninduced agglutination appears to involve the affinity of a receptor site, possibly dextransucrase, on the surface of several cells for common dextran molecules.
Mode of Action of Pesticin
Authors: Elgat Maya , Ben-Gurion Renana
Published: January 2020

The mode of action of pesticin, a bacteriocin produced by many strains ofPasturella pestis, was studied. Pesticin action on macromolecular synthesis of a sensitive strain ofEscherichia coli, strain φ, was found to have features similar to those of colicin E2-317 acting on the same strain. After exposure to pesticin, deoxyribonucleic acid synthesis was arrested and ribonucleic acid was degraded, but little effect was observed on protein synthesis. Pesticin, like colicin E2-317, induced lysogenicE. coliφ (P1), but, unlike the colicin, was active in the presence of dinitrophenol. Trypsin was found to reverse pesticin action up to 15 min after its addition at 40 C toE. coliφ. Pesticin action was studied on three sensitive bacterial strains,P. pestis2C,P. pseudotuberculosis, andE. colistrain φ, which vary widely in their optimal growth temperature.P. pestisgrows best at 29 C,P. pseudotuberculosisat 37 C, andE. coliφ at 40 C. It was found that pesticin action on all three strains was optimal at 40 C. Whereas the titer of pesticin was the same on all three strains when determined on agar,E. coliφ was the most sensitive to pesticin action in broth. No action of pesticin in broth onP. pseudotuberculosiswas observed unless Ca ions were added. The effect was not immediate; that is, the cells had to be grown in a medium containing Ca++before they displayed sensitivity to pesticin.
Taxonomic Comparison of the Amino Termini of Microbial Cell Proteins
Authors: Sarimo Seppo S. , Pine Martin J.
Published: January 2020

A comparison was made of the distribution of amino terminal end groups in the cellular proteins of a number of microbes. Among the procaryotes, methionine is a highly variable but virtually ubiquitous major protein end group. This is consistent with its possible role as a general amino acid initiator of protein biosynthesis in the procaryotes. Generally, however, alanine is the most abundant of the major end groups, followed in decreasing order by serine, threonine, the acidic amino acids, and occasionally lysine. No other new major end-groups were found. Among 15 representatives of theEnterobacteriaceae, retention of the initiating methionine terminus of the cellular protein varies considerably at a tribal level and is randomized at a familial level. The profiles of the five remaining end groups, however, are strikingly uniform, and are, for example, close to but significantly different from those of theErwineae. Among the taxonomically more heterogeneousBacillaceae, end-group profiles vary more and are sometimes unrelated. End-group analysis is thus particularly useful as a molecular criterion of taxonomy in assessing familial homogeneity. Free NH2termini in eucaryote cell proteins are fewer, and they have increased acidic amino acid components and no methionine; they are otherwise similar to those of the procaryotes.
Serological and Bacteriological Investigation of
Mycobacterium ranae
(
fortuitum
)
Authors: Stanford J. L. , Gunthorpe W. J.
Published: January 2020

Twenty strains of a species of fast growing
Mycobacterium
, some named
M. fortuitum
and others said to be similar to the strain of
M. peregrinum
, in the possession of the National Collection of Type Cultures, were examined serologically and bacteriologically. They were all found to be of the same species, but they were divisible into four serotypes (I to IV), on a basis of three variable antigens, which do not exactly correspond to the subspecies described in previous reports. The strains varied in the number of years that they had been kept in culture and were of widely divergent origin. With the exception of serotype II strains, which all came from sputa from Welsh miners, the serotypes were independent of years in culture or site of origin. Based on bacteriological and serological identity and chronological priority, we consider that
M. ranae
(Kuster) Bergey et al. should be reinstated in place of
M. fortuitum
Cruz. A modified scheme for identification of the species is proposed, which would not exclude any of the four serotypes.
Immunological Relationships Among Some Species of Extremely Halophilic Bacteria
Authors: Zwilling Bruce S. , Rowen Robert , Stotzky G.
Published: January 2020

Rabbits were immunized with four strains of halobacteria,
Halobacterium halobium
NRL,
H. halobium
R-1,
H. salinarium
NRL-9, and
H. cutirubrum
NRL-10, that had been fixed with formaldehyde. The antisera obtained detected the presence of an antigen common to the
Halobacterium
genus and, after absorption, detected three distinct antigenic groups within the
Halobacterium
genus. A fourth group was agglutinated only by unabsorbed sera.
Inhibition of
Aerobacter
Cephalosporin β-Lactamase by Penicillins
Authors: Fleming P. C. , Goldner M. , Glass D. G.
Published: January 2020

Cephalosporinase (β-lactamase) was obtained from cell washings of
Aerobacter
(
Enterobacter
)
cloacae
as a highly active preparation. An alkalimetric method was used to determine the enzyme activity and to estimate its inhibition by 6-amino-penicillanic acid derivatives. Their order of decreasing inhibitory effect was as follows: cloxacillin, oxacillin, methicillin, ampicillin, and penicillin G. We found that 2 to 3 ng of cloxacillin per ml was sufficient to decrease the enzyme activity by 50% in the presence of 400 μg of cephalosporin C per ml. Cloxacillin exerted a potentiating effect on the inhibition of the
E. cloacae
organisms by cephalosporin C.
Induction of Experimental Chronic Arthritis in Rabbits by Cell-free Fragments of
Erysipelothrix
Authors: White Thomas G. , Puls Jerry L.
Published: January 2020

A cell-free crude extract of
Erysipelothrix rhusiopathiae
injected by high pressure jet into the knee-joint of rabbits stimulated an acute, mild inflammatory reaction. Additional injections at 3-day intervals induced a chronic condition characterized by hyperplasia of the synovial cells and hypertrophy of the villi, due to infiltration by lymphocytes and plasma cells which formed aggregates resembling Allison-Ghormley bodies. There was also extensive proliferation of stroma vasculature and fibrous tissue. A similar jet injection of the diluent produced an early, transient, acute, and mild inflammation. A mechanism is postulated for fixation of one or more of the chemically characterized antigens in or near the synovium as a means of inducing the localized inflammatory response that predisposes the joint to infection.
Deoxyribonucleic Acid Base Composition and Homology Studies ofLeptospira
Authors: Haapala Daniel K. , Rogul Marvin , Evans L. B. , Alexander A. D.
Published: January 2020

Four distinct genetic groups of leptospiras were demonstrated among selected pathogenic and “biflexa” serological types. Pathogenic leptospiras could be divided into two groups on the basis of per cent guanine + cytosine (GC) in their deoxyribonucleic acid (DNA). One group had 36 ± 1%, the other 39 ± 1%. The biflexa strains had DNA of 39 ± 1% GC, but were further separated into two groups on the basis of DNA-annealing tests. Strains within groups had a high degree of specific duplex formation (75% binding or more with reference to the homologous DNA). There was little or no genetic relatedness between strains of the four groups (less than 10% DNA homology). The thermal elution midpoint of heterologous DNA duplexes was always lower than the homologous reaction. The serological relationships among strains were not meaningful in terms of relatedness determined by specific duplex formation.
Laboratory Characteristics of Paratyphoid B Vaccines Tested in Controlled Field Trials
Authors: Hejfec L. B. , Levina L. A.
Published: January 2020

The immunization of human beings with paratyphoid B vaccines, in doses producing a marked protective effect in field trials, resulted in H-agglutinin titers that were significantly higher than those produced by ineffective doses. In immunization of rabbits and white mice, the same difference in doses had a significant effect on the ability of vaccines to stimulate the formation of H and O antibodies. A parallel was noted between the effectiveness of vaccine for human beings and the activity of sera of the corresponding group of people in the passive mouse-protection test, with a correlation between such activity of sera and the 19
S
O-hemagglutinin titers. The data obtained suggested as promising the determination of agglutinin dynamics in the sera of inoculated human beings and animals to evaluate the antigenic activity of paratyphoid B vaccines in the laboratory. The passive mouse-protection test with human sera holds promise for laboratory evaluation of the effectiveness of paratyphoid B vaccines. At the same time, none of the variation of the active mouse-protection test employed permitted a significant difference to be detected between the vaccines effective and ineffective for man. Comparison of data on the frequency and degree of febrile vaccine reactions in man with results of laboratory evaluation of vaccine toxicity showed that, provided a reference vaccine with known pyrogenic capacity for man was employed, the study of stress effect of vaccines on guinea-pigs (determination of 17-oxycorticosteroid content) may permit prediction of the reactive power of the vaccine. No correlation was found between the pyrogenic capacity of vaccines for man and their toxicity for mice.
Use of Bacteriophage-resistant Mutants to Study the Nature of the Bacteriophage Receptor Site of
Staphylococcus aureus
Authors: Chatterjee Anadi N.
Published: January 2020

Bacteriophage-resistant strains of
Staphylococcus aureus
H were isolated after mutagenesis with
N
-methyl-
N′
-nitro-
N
-nitrosoguanidine. Cell walls isolated from about half of these resistant strains were incapable of inactivating phages and were shown to lack
N
-acetyl-
d
-glucosamine (GlcNAc) in their cell wall teichoic acid. Apart from the lack of GlcNAc, two of these mutant strains were deficient in cell wall phosphorus and ester-linked
d
-alanine. These two strains were also found to be resistant to both phage K and a host-range mutant isolated from the parent phage. These two phages could lyse the other phage-resistant mutants which lacked GlcNAc in their teichoic acid. Cell walls from the remaining phage-resistant mutant strains did inactivate phages and were found to have normal cell wall teichoic acid. Although GlcNAc in teichoic acid was required for phage inactivation, no difference in phage inactivation ability was detected with cell walls isolated from strains of
S. aureus
having exclusively α- or exclusively β-linked GlcNAc in their cell wall teichoic acid.
Catalase-Aminotriazole Method for Measuring Secretion of Hydrogen Peroxide by Microorganisms
Authors: Cohen Gerald , Somerson Norman L.
Published: January 2020

A new method for measuring the secretion of H
2
O
2
has been based upon an H
2
O
2
-dependent inhibition of catalase by 3-amino-1,2,4-triazole. The conversion of an H
2
O
2
-secretion rate into a catalase inhibition rate amplified a relatively small molar concentration of H
2
O
2
and provided a highly specific and sensitive method for quantitatively measuring H
2
O
2
. A major advantage of this approach is that it does not require extensive accumulation of H
2
O
2
in the environment. The method was successfully employed to measure H
2
O
2
secretion by
Mycoplasma pneumoniae
, which possesses a peroxidase-like activity that limits the accumulation of H
2
O
2
in the environment.