bluuebunny/crossref_metadata_2025 huggingface dataset:
Purification and Properties of a Polygalacturonic Acid
Trans
-Eliminase Produced by
Bacillus pumilus
Authors: Dave Bhalchandra A. , Vaughn Reese H.
Published: January 2020

A strain of
Bacillus pumilus
produced an extracellular pectic enzyme with polygalacturonic acid as the substrate. This enzyme, with optimal activity at
p
H 8.0 to 8.5, produced reaction products that strongly absorbed light at 232 nm, indicating the presence of a pectic acid
trans
-eliminase (PATE). Neither pectin esterase nor polygalacturonase was detected in the cell-free culture fluid. Chromatographic examination of the end products revealed the presence of large quantities of unsaturated oligouronides unlike those found with
B. polymyxa
. It was found that the PATE was produced extracellularly during the negative logarithmic death phase of the organism. The filtrate from sonically treated cells did not show any activity for PATE or hydrolases for lower oligogalacturonides at any time during the growth cycle. The enzyme was inducible. Pectin, National Formulary (NF) was the best inducer, followed by polygalacturonic acid and galacturonic acid. Enzyme activity was markedly stimulated by calcium and other divalent ions. Copper and cobalt ions were inhibitory. The partially purified enzyme showed no significant activity on pectin containing a high methoxyl content (96% esterified). However, pectin NF with a lower methoxyl content (68% esterified) was attacked to a degree by the partially purified and crude enzyme preparations. The initial rate of PATE activity increased up to 60 C, about 16-fold higher than that observed at room temperature. The activation energy was calculated as 12,183 cal/mole. A protective action of calcium chloride against heat inactivation of the PATE was observed. Degradation of polygalacturonic acid by this enzyme produced several unsaturated oligouronides soon after its addition to the substrate. The major endproduct was thought to be different from that of other known PATE enzymes. Paper chromatographic studies and viscosity measurements disclosed the random cleaving nature of the enzyme an endo-PATE.
Physical and Functional Characteristics of R-Factor Deoxyribonucleic Acid Segregated into
Escherichia coli
Minicells
Authors: Levy Stuart B.
Published: January 2020

Both fi
+
and fi
−
type R factors function as intact replicative units when segregated into
Escherichia coli
minicells. Hybridization studies demonstrate that at least 95% of the deoxyribonucleic acid (DNA) in R
+
minicells is episomal in origin. About half of the DNA can be extracted in a closed circular form and about 75% of the DNA is membrane associated. DNA, ribonucleic acid, and protein synthesis proceeds in R
+
minicells in contrast to R
−
minicell controls. The system offers a unique opportunity to study a relatively small replicative unit in a native cell environment and a simple means of isolating large quantities of episomal DNA.
Phenylalanine and Tyrosine Biosynthesis in
Escherichia coli
K-12: Mutants Derepressed for 3-Deoxy-
d
-Arabinoheptulosonic Acid 7-Phosphate Synthetase (phe), 3-Deoxy-
d
-Arabinoheptulosonic Acid 7-Phosphate Synthetase (tyr), Chorismate Mutase T-Prephenate Dehydrogenase, and Transaminase A
Authors: Im S. W. K. , Davidson H. , Pittard J.
Published: January 2020

Mutant strains of
Escherichia coli
have been isolated in which the synthesis of 3-deoxy-
d
-arabinoheptulosonic acid 7-phosphate (DAHP) synthetase (phe) is derepressed, in addition to those enzymes of tyrosine biosynthesis previously shown to be controlled by the gene
tyrR
. The major enzyme of the terminal pathway of phenylalanine biosynthesis chorismate mutase-prephenate dehydratase is not derepressed in these strains. Genetic analysis of the mutants shows that the mutation or mutations causing derepression map close to previously reported
tyrR
mutations. A study of one of the mutations has shown it to be recessive to the wild-type allele in a diploid strain. It is proposed that the
tyrR
gene product is involved in the regulation of the synthesis of DAHP synthetase (phe) as well as the synthesis of DAHP synthetase (tyr), chorismate mutase-prephenate dehydrogenase, and transaminase A.
Electron Microscopy of Tissue Culture Cells Infected withBrucella abortus
Authors: Hatten Betty A. , Huang Shyi Yi , Schulze M. L. , Sulkin S. Edward
Published: January 2020

Thin sections of hamster kidney tissue cultures were examined by electron microscopy over a 7-day period after infection withBrucella abortus3183. Numerous bacteria and structures resembling L-forms were present both intracellularly and extracellularly after the first 24 hr of infection. Most intracellular microorganisms were enclosed by a cytoplasmic membrane, but in a few instances no limiting membrane was detected. After 4 to 7 days, fewer microorganisms were present, and most normal-appearing bacteria were intracellular, particularly in antibiotic-treated cultures. Structures typical ofBrucellaL-forms were extracellular at the latter time intervals. Several structures were observed in cells from infected cultures whose relationship to the infecting organisms is not known. These consisted of various membranous structures within cytoplasmic vacuoles, myelin-like structures surrounding occasional intracellular organisms, and small bodies present within vacuoles and extracellularly. The latter structures observed throughout the experimental period appeared to occur more frequently as the duration of the infection increased.
Fiber-Structured Material in a Fraction of
Bacillus subtilis
Authors: Hiragi Yuzuru , Kadota Hajime
Published: January 2020

The paracrystal fractions of two species of
Bacillus
contain similarly structured fibrous material whose unit cell is hexagonal, with cell dimensions of a = 0.719 nm and c = 0.963 nm.
Transcription of the Operator Proximal and Distal Ends of the Tryptophan Operon: Evidence that
trpE
and
trpA
Are the Delimiting Structural Genes
Authors: Rose John K. , Yanofsky Charles
Published: January 2020

Measurements of the time required for transcription of regions of known genetic length in the tryptophan operon of
Escherichia coli
indicate that there are no major unidentified structural genes in the operon either before the operator proximal E gene or after the operator distal A gene.
Characterization of Mutants of
Escherichia coli
Temperature-Sensitive for Ribonucleic Acid Regulation: an Unusual Phenotype Associated with a Phenylalanyl Transfer Ribonucleic Acid Synthetase Mutant
Authors: Atherly Alan G. , Suchanek Martha C.
Published: January 2020

A mutant strain AA-522, temperature-sensitive for protein synthesis, was isolated from a stringent strain (CP-78) of
Escherichia coli
K-12. The mutant strain has a relaxed phenotype at the nonpermissive growth temperature. Protein synthesis stops completely at 42 C, whereas the rate of ribonucleic acid (RNA) synthesis is maintained at 20% of the 30 C rate. Sucrose-gradient centrifugation analysis of RNA-containing particles formed at 42 C indicated the presence of “relaxed particles.” These particles possess 16
S
and 23
S
RNA and are precursors to normal 50
S
and 30
S
ribosomal subunits. A search for the temperature-sensitive protein responsible for the halt in protein synthesis implicated phenylalanyl transfer RNA (tRNA) synthetase. Essentially no enzyme activity is detected in vitro at 30 or 40 C. Analysis of phenylalanyl tRNA synthetase activity in revertants of strain AA-522 indicated the presence of intragenic suppressor mutations. Revertants of strain AA-522 analyzed for the relaxed response at 42 C were all stringent; strain AA-522 was stringent at 30 C. These data indicate that a single mutation in phenylalanyl tRNA synthetase is responsible for both a block in protein synthesis and the relaxed phenotype at 42 C.
Potassium Transport Loci in
Escherichia coli
K-12
Authors: Epstein Wolfgang , Kim Byung S.
Published: January 2020

Mutants of
Escherichia coli
K-12 requiring considerably elevated concentrations of potassium for growth are readily obtained as double mutants combining a
kdp
mutation with a mutation in one or more of five other loci. These loci are referred to as
trk
, for transport of K, because these mutations result in alterations in K transport. The
kdp
mutation is essential in the isolation and identification of this type of mutant; in a Kdp
+
strain, the presence of a
trk
mutation does not prevent growth of the strain in media containing very low concentrations of K. The
trk
loci are widely scattered over the
E. coli
chromosome; none of them is very near any other
trk
locus or near the
kdp
genes.
Macromolecular Synthesis in
Bacillus subtilis
During Development of the Competent State
Authors: Dooley Douglas C. , Hadden Charles T. , Nester Eugene W.
Published: January 2020

Rates of deoxyribonucleic acid, ribonucleic acid, and protein synthesis were examined in purified competent cells of
Bacillus subtilis
during the development of the transformable state. To become competent, a cell must depart from the normal course of vegetative growth and pass through a precompetent phase beginning as early as 90 to 180 min before the appearance of transformability. While in the precompetent state, the cell decreases its rate of deoxyribonucleic acid synthesis and lowers its ratio of ribonucleic acid synthesis to protein synthesis. This altered pattern of synthesis eventually leads to a decreased buoyant density of precompetent cells. Once a cell has become both precompetent and low in density, it can be converted to a competent (transformable) cell. The early alterations in macromolecular synthesis were found in two competence regimens, one utilizing a nutritional step-down and one free of such a shift. The data imply that the precompetent state is a generalized characteristic of the
B. subtilis
transformation system and is not specific to the procedure used to allow competence development. Since precompetence-specific events occur very early in a competence regimen, we conclude that the induction of precompetence is unrelated to sporulation or a nutritional shift.
Macromolecular Sieving by the Dormant Spore of
Bacillus cereus
Authors: Scherrer Réne , Beaman T. Cabrera , Gerhardt Philipp
Published: January 2020

The threshold surface porosity in the dormant spore of
Bacillus cereus
strain T was assessed by measuring passive permeabilities to a series of polydisperse polyethylene glycol samples which increased in average molecular size. The apparent exclusion threshold at diffusional equilibrium corresponded to a polymer of number-average molecular weight (
¯M
n
) = 150,000 and equivalent hydrodynamic radius (
¯r
ES
) = 16 nm, which confirmed a previous report. However, analytical gel chromatography before and after uptake by the spores revealed that only the low molecular weight fractions in a polymer sample distribution were taken up. From graphical analyses of the changes in molecular weight distributions, a quasi-monodisperse exclusion threshold was determined corresponding to
M
n
= 8,000 and
r
ES
= 3.2 nm. Thus, the equivalent porosity in the limiting outer integument appeared much more restrictive than heretofore shown for spores, although still more open than the monodisperse equivalent for the cell wall of vegetative bacilli.
Adenylate Energy Charge inEscherichia coliDuring Growth and Starvation
Authors: Chapman Astrid G. , Fall Lana , Atkinson Daniel E.
Published: January 2020

The value of the adenylate energy charge, [(adenosine triphosphate) + ½ (adenosine diphosphate)]/[(adenosine triphosphate) + (adenosine diphosphate) + (adenosine monophosphate)], inEscherichia colicells during growth is about 0.8. During the stationary phase after cessation of growth, or during starvation in carbon-limited cultures, the energy charge declines slowly to a value of about 0.5, and then falls more rapidly. During the slow decline in energy charge, all the cells are capable of forming colonies, but a rapid fall in viability coincides with the steep drop in energy charge. These results suggest that growth can occur only at energy charge values above about 0.8, that viability is maintained at values between 0.8 and 0.5, and that cells die at values below 0.5. Tabulation of adenylate concentrations previously reported for various organisms and tissues supports the prediction, based on enzyme kinetic observations in vitro, that the energy charge is stabilized near 0.85 in intact metabolizing cells of a wide variety of types.
Biosynthesis of 7,8-Diaminopelargonic Acid, a Biotin Intermediate, from 7-Keto-8-Aminopelargonic Acid and
S
-Adenosyl-
l
-Methionine
Authors: Eisenberg Max A. , Stoner Gerald L.
Published: January 2020

Resting cells of
Escherichia coli
strain D302(
bioD
302) can synthesize 7,8-diaminopelargonic acid from 7-keto-8-aminopelargonic acid. The product of this aminotransferase reaction has been identified by paper chromatography and electrophoresis. Glucose enhances the vitamer yield twofold. Of the 19 amino acids tested as amino donors, only methionine proved to be significantly stimulatory. In cell-free extracts, however, methionine was completely inactive unless both adenosine triphosphate (ATP) and Mg
2+
were present.
S
-Adenosyl-
l
-methionine (SAM) was about 10 times more effective than methionine, ATP, and Mg
2+
. The optimal conditions for the reaction were determined, and substrate inhibition was found for 7-keto-8-aminopelargonic acid. It has been possible to eliminate certain impurities as amino donors in the commercial preparation of SAM and those that may arise in enzymatic reactions in which SAM is a substrate. The direct participation of SAM in the aminotransferase reaction seems a likely possibility.
Mutants of
Escherichia coli
K-12 Blocked in the Final Reaction of Ubiquinone Biosynthesis: Characterization and Genetic Analysis
Authors: Stroobant P. , Young I. G. , Gibson F.
Published: January 2020

The ubiquinone precursor 2-octaprenyl-3-methyl-5-hydroxy-6-methoxy-1, 4-benzoquinone was isolated from two ubiquinone-deficient mutants of
Escherichia coli
and identified by nuclear magnetic resonance and mass spectrometry. The results of genetic analysis of the mutants indicate that each mutant carries a mutation in a gene designated
ubiG
which was located, by cotransduction with the
nalA
and
glpT
genes, at minute 42 on the
E. coli
chromosome.
Further Studies on the Binding of Vitamin B
12
to the Cell Wall of a B
12
-Requiring
Lactobacillus
Authors: Sasaki Takashi
Published: January 2020

The vitamin B
12
-binding property of
Lactobacillus leichmannii
ATCC 7830 has been studied. The organism could bind 0.52 μg of B
12
per mg of cells. With regard to the cellular site for B
12
accumulation, three-quarters of the B
12
bound to the cell was found in the crude cell wall fraction, and the remaining one-quarter was found in the particulate (ribosome) fraction. After receiving enzymatic treatments with ribonuclease, lipase, and trypsin, the wall fraction retained three-fifths of the initial B
12
. The possibility of cross-contamination of the wall and particulate fractions was excluded by measuring the contents of ribonucleic acid and hexosamines in each fraction. The B
12
-binding activity of the wall was destroyed by pretreatment of the wall with pepsin, Pronase, or trypsin. However, once bound to the wall, the B
12
was not released by the same treatments. These facts suggest that B
12
is bound to a polypeptide in the wall on which these enzymes act and that, once bound, B
12
somehow inhibits the enzymatic actions as described earlier with
L. delbrueckii
no. 1. A B
12
-polypeptide complex was isolated by treatment with 0.2
n
HCl from walls to which B
12
had been bound. The complex was then purified. The complex moves as a single band on polyacrylamide gel electrophoresis. Its molecular weight was estimated around 21,500 with microheterogeneity on a Sephadex G-75 column. The mode of B
12
binding was found to be similar to that of
L. delbrueckii
.
Ribosome Synthesis in Thermally Shocked Cells of
Staphylococcus aureus
Authors: Rosenthal Leonard J. , Martin Scott E. , Pariza Michael W. , Iandolo John J.
Published: January 2020

Thermally shocked cells of
Staphylococcus aureus
rapidly synthesized ribonucleic acid (RNA) during the early stages of recovery. During this period, protein synthesis was not observed and occurred only after RNA had reached a maximum level. Even in the absence of coordinated protein synthesis, a large portion of the RNA appeared in newly synthesized ribosomes. Although the 30
S
subunit was specifically destroyed by the heating process, both ribosomal particles were reassembled during recovery. The addition of chloramphenicol did not inhibit the formation of the ribosomal subunits, nor was the presence of immature chloramphenicol particles detected. Extended recovery with highly prelabeled cells showed that the original ribosomal proteins present before heating are conserved and recycled. Furthermore, the data indicate that the 50
S
subunit is turned over and used as a source of protein for new ribosome assembly. Kinetic studies of the assembly process by pulse labeling have not revealed the presence of the normally reported precursor particles. Rather, the data suggest that assembly may occur, in this system, in a manner similar to that reported for in vitro assembly of
Escherichia coli
subunits.
Nonidentity of
Bdellovibrio bacteriovorus
Strains 109D and 109J
Authors: Rittenberg Sydney C.
Published: January 2020

Two strains of
Bdellovibrio bacteriovorus
, both designated as 109 in the literature, differ. They should be referred to as 109D and 109J to avoid further confusion.
Germination of Heat- and Alkali-Altered Spores of
Clostridium perfringens
Type A by Lysozyme and an Initiation Protein
Authors: Duncan Charles L. , Labbe Ronald G. , Reich Robert R.
Published: January 2020

The normal system functioning in the utilization of metabolizable germinants by both heat-sensitive and heat-resistant spores of
Clostridium perfringens
was inactivated by heat or by treatment of the spores with alkali to remove a soluble coat protein layer. Altered spores were incapable of germination (less than 1%) and outgrowth (less than 0.0005%) in complex media without the addition of either lysozyme or an initiation protein produced by
C. perfringens
. The addition of either of these agents permitted, in the case of alkali-treated spores, both 90 to 95% germination and outgrowth, as measured by colony formation. In the case of heat-damaged spores, only 50% germination and 2% outgrowth resulted from addition of the initiation protein, whereas lysozyme permitted 85% germination and 8% outgrowth. Alteration of the spores by heat or alkali apparently inactivated the normal lytic system responsible for cortical degradation during germination. Kinetics of production of the initiation protein and conditions affecting both its activity and that of lysozyme on altered spores are described.
Halophilic Amylase from a Moderately Halophilic
Micrococcus
Authors: Onishi Hiroshi
Published: January 2020

A moderately halophilic
Micrococcus
sp., isolated from unrefined solar salt, produced a considerable amount of extracellular dextrinogenic amylase when cultivated aerobically in media containing 1 to 3
m
NaCl. The
Micrococcus
amylase had maximal activity at
p
H 6 to 7 in 1.4 to 2
m
NaCl or KCl at 50 C. Calcium ion and a high concentration of NaCl or KCl were essential for activity and stability of the amylase. The salt response of the amylase depended greatly on the
p
H and temperature of the enzyme assay.
Derivation of an F-Merogenote and a φ80 High-Frequency Transducing Phage Carrying the Histidine Operon of
Salmonella
Authors: Voll M. J.
Published: January 2020

An F′ factor, FS400, carrying the
his
operon, the
gnd
gene, and the
rfb
gene cluster of
Salmonella typhimurium
was isolated. FS400 was introduced into an
Escherichia coli
strain having a lengthy deletion of the
his
gene region. From this strain, Hfr derivatives were isolated which had the F′ factor integrated in the
tonB
locus near the attachment site of φ80. One of the Hfr strains was lysogenized with a heat-inducible,
h
mutant of φ80, and from this strain a high-frequency transducing phage carrying the
his
genes and the
gnd
gene of
Salmonella
was isolated.
Physical Aggregation and Functional Reconstitution of Solubilized Membranes of
Bacillus stearothermophilus
Authors: Kiszkiss David F. , Downey R. J.
Published: January 2020

Isolated membranes of
Bacillus stearothermophilus
2184D can be disrupted by treatment with sodium dodecyl sulfate (SDS). This disruption is attended by a decreased turbidity of membrane suspensions and a differential loss of activities of the electron transport system. Reduced methyl viologen (MVH)-nitrate reductase activity is insensitive to SDS treatment, whereas reduced nicotinamide adenine dinucleotide (NADH)-nitrate reductase and cyanide-sensitive NADH oxidase activities are decreased by 80% at an SDS concentration of 0.5 mg/mg of membrane protein. NADH-menadione reductase activity is unaffected at this SDS concentration, but at higher detergent levels it also decreases in activity. The abilities of NADH to reduce and nitrate to oxidize the cytochrome components of the membrane were also decreased after SDS treatment. Dilution of solubilized membrane in buffer containing divalent cation results in formation of an aggregate with an increased turbidity and reconstituted NADH-nitrate reductase and cyanide-sensitive NADH oxidase activities. Of several cations tested, magnesium was the most effective, and the reconstitution process was
p
H-dependent with an optimum at
p
H 7.4. Intact and aggregated membranes had similar densities and cytochrome contents, and the sensitivity of NADH-nitrate reductase to several inhibitors was similar in intact and reconstituted membranes.
Fatty Acid Composition of Unicellular Strains of Blue-Green Algae
Authors: Kenyon C. N.
Published: January 2020

The fatty acids of 34 strains of unicellular blue-green algae provisionally assigned to the genera
Synechococcus, Aphanocapsa, Gloeocapsa, Microcystis
, and
Chlorogloea
by Stanier et al. have been chemically characterized. The strains analyzed can be divided into a series of compositional groups based upon the highest degree of unsaturation of the major cellular fatty acids. Twenty strains fall into the group characterized by one trienoic fatty acid isomer (α-linolenic acid), and seven strains fall into a group characterized by another trienoic acid isomer (γ-linolenic acid). These groups in many cases correlate well with groupings based upon other phenotypic characters of the strains, e.g., deoxyribonucleic acid base composition. The assignment of a strain to a compositional group is not altered when the strain is grown under a variety of different culture conditions. All strains contain glycolipids with the properties of mono- and digalactosyldiglycerides.
Fine Structure of Ascosporogenesis in
Nematospora coryli
Peglion, a Pathogenic Yeast
Authors: Plurad Santiago B.
Published: January 2020

Observations with the electron microscope of the early stages of ascospore formation in
Nematospora coryli
Peglion reveal the following sequence of events. Partial dissociation of the nuclear membrane is followed by the appearance of unit membranes. Each unit membrane gives rise to two pairs of double membranes delimiting the ascospores from the epiplasm of the ascus. Enlarged mitochondria which have a granular matrix and limited cristae development are also regularly seen.
Specific Role of Sex Pili in the Effective Eliminatory Action of Sodium Dodecyl Sulfate on Sex and Drug Resistance Factors in
Escherichia coli
Authors: Adachi Haruyo , Nakano Mariko , Inuzuka Manabu , Tomoeda Munemitsu
Published: January 2020

Evidence is presented for the specific role of sex pili in the eliminatory action of sodium dodecyl sulfate (SDS) on sex (F) and drug resistance (R) factors in
Escherichia coli
K-12 strains leading to their loss. SDS at 0.03% concentration lysed JE3100 F
8
+
(F-
gal
)/

gal
−
fla
−
pil
−

in Penassay broth after they had grown exponentially and reached maximum growth to the extent that the agent at concentrations higher than 1% did. However, the agent was only effective in eliminating sex factors from JE3100 in high frequencies at concentrations higher than 1%. Increase of osmotic pressure of the culture with SDS at concentrations as low as 0.03 to 0.1% by addition of sucrose led to the substantial increase of elimination efficiency. Reconstruction experiments between F
8
+
and F
−
cells in the SDS culture revealed the selective growth of F
−
cells as well as a delay of maximum growth of F
−
variants derived from F
8
+
cells, compared with those of F
8
+
cells, as well as F
−
cells originally added to the culture. The agent was not very effective in eliminating sex factors from JE3427 F
8
m
+
5/
fla
−
pil
−
cells which lack the function of production of F pili. F
8
m
+
5 cells showed a sensitivity toward SDS intermediate between those of F
8
+
and F
−
cells. SDS was further effective in eliminating R factors from KE132 R
100-1
+
/
fla
−
pil
−
cells in high efficiency; however, the action was not efficient with KE133 F
100
+
cells possibly with fewer sex pili than R
100-1
+
. Action of acridine orange on these F
+
or R
+
strains was found to be different in some aspects from that of SDS.
Close Linkage Between
Ochre
and Missense Suppressors in
Escherichia coli
Authors: Orias E. , Gartner T. K. , Lannan J. E. , Betlach M.
Published: January 2020

It was previously shown that the
ochre
suppressor mutation
sup15B
in
Escherichia coli
determines the accumulation of altered 30
S
ribosomal subunits and the presence of altered transfer ribonucleic acid (tRNA) capable of suppressing in vitro the UAG codon. This mutation has been mapped in the present study by means of conjugation and transduction experiments. After establishing the location of
sup15B
near
argH
, the following order was determined for the markers tested:
metB-argH
-(
sup15B, supA36
)-
rif-thi
. A comparison of location, growth rate, and suppressor pattern determined by
sup15B
and
supM
indicates the high probability that both suppressor mutations are identical. This study has also yielded a more precise location for the rifampin resistance gene. The most interesting finding is the very close (if not adjacent) location of the suppressor mutations
sup15B
and
supA36
, both of which determine tRNA alterations.
Biochemical and Genetic Characterization of β-Glucosidase Mutants in
Saccharomyces lactis
Authors: Tingle Marjorie , Halvorson Harlyn O.
Published: January 2020

Mutants with reduced activity for β-glucosidase (β-
d
-glucoside glucohydrolase EC 3.2.1.21) were isolated from the haploid yeast
Saccharomyces lactis
. Tetrad analysis indicated that in each mutant a single genetic factor, closely linked or allelic to the structural gene for β-glucosidase (B locus), is responsible for the decreased activity. β-Glucosidases produced by wild-type and mutant strains are similar in molecular size and charge but differ in catalytic properties, thermal stability, and serological specificity, indicating that mutants are in the structural gene. All mutants retained their capacity to be induced by either methyl-β-
d
-glucoside or glucose. In all cases, the mutant phenotype was dominant in heterozygous diploids.
Localization and Biological and Physicochemical Properties of the Cell Wall Lipopolysaccharide of
Rhodopseudomonas capsulata
Authors: Weckesser J. , Drews G. , Ladwig R.
Published: January 2020

Electron micrographs of phenol-water-extracted lipopolysaccharide (LPS) of
Rhodopseudomonas capsulata
show filamentous and netlike aggregates. Treatment of the LPS with sodium deoxycholate resulted in a reversible splitting into subunits. The LPS represents a cell wall constituent with O-antigenic specificity. In passive hemagglutination tests, high titers were obtained when erythrocytes sensitized with untreated or heat-treated LPS were incubated with antisera obtained by immunization of rabbits with whole cells of
R. capsulata
. The alkali-treated LPS was not active in this test. Mouse lethality tests have shown that the LPS of
R. capsulata
is less toxic than LPS of
Escherichia coli
. Also, the X-ray protection efficacy and the phagocytic activity stimulation of LPS from
R. capsulata
in mice are small, as compared with LPS of
E. coli
. Incubation of living bacteria in saline (37 C) resulted in a solubilization of an LPS-protein-lipid complex from the outer layer of the cell wall. The isolated complex contained the components which were found in the LPS. In addition, 20% amino acids and a large amount of palmitic and stearic acids, which are typical phospholipid components, were present.
Sporulation and Enterotoxin Production by Mutants of
Clostridium perfringens
Authors: Duncan Charles L. , Strong Dorothy H. , Sebald Madeleine
Published: January 2020

The ability of
Clostridium perfringens
type A to produce an enterotoxin active in human food poisoning has been shown to be directly related to the ability of the organism to sporulate. Enterotoxin was produced only in a sporulation medium and not in a growth medium in which sporulation was repressed. Mutants with an altered ability to sporulate were isolated from an sp
+
ent
+
strain either as spontaneous mutants or after mutagenesis with acridine orange or nitrosoguanidine. All sp
0
−
mutants were ent
−
. Except for one isolate, these mutants were not disturbed in other toxic functions characteristic of the wild type and unrelated to sporulation. A total of four of seven osp
0
mutants retained the ability to produce detectable levels of enterotoxin. None of the ent
−
mutants produced gene products serologically homologous to enterotoxin. A total of three sp
−
mutants, blocked at intermediate stages of sporulation, produced enterotoxin. Of these mutants, one was blocked at stage III, one probably at late stage IV, and one probably at stage V. A total of three sp
+
revertants isolated from an sp
−
ent
−
mutant regained not only the ability to sporulate but also the ability to produce enterotoxin. The enterotoxin appears to be a sporulation-specific gene product; however, the function of the enterotoxin in sporulation is unknown.
Effect of Carbon Source on Size and Associated Properties of
Bacillus megaterium
Spores
Authors: Hitchins A. D. , Greene R. A. , Slepecky R. A.
Published: January 2020

The size of the spores produced by
Bacillus megaterium
ATCC 19213 depended upon the nature of the carbon source present in the defined medium in which they were produced. Homogeneous preparations of small (0.38 μm
3
), nearly spherical spores were produced after batch culture in the presence of 2.8 m
m
citrate, and large (1.17 μm
3
), oblong spores were produced by replacement culture in the presence of 7.35 m
m
acetate. Large and small spores had approximately the same deoxyribonucleic acid content, density, and heat resistance. Large spores contained about 2.5 times the dipicolinic acid, glucosamine, ribonucleic acid, Mn
2+
, and lipid and about 1.5 times the Mg
2+
, Fe
2+
, Ca
2+
, and dry weight of small spores. Large spores were especially enriched in Zn
2+
(4.5-fold). More protein (1.5-fold) was extracted from small spores with 1
n
NaOH than from large spores, possibly indicating a difference in the spore coats, but large spores contained about twice the Kjeldahl nitrogen of small spores. A difference in the coats may account for the fact that, unlike small spores, large spores showed improved germination with increased times and temperature of heat shocking. The possibility of determining the location of some of these substances within the spore by comparing the compositional ratios with estimated volumes of specific spore layers is discussed.
Electron Transport Systems of
Nitrosomonas
: Isolation of a Membrane-Envelope Fraction
Authors: Hooper A. B. , Erickson R. H. , Terry K. R.
Published: January 2020

Freezing and thawing of
Nitrosomonas
, followed by centrifugation of the homogenate at 3,000 ×
g
, resulted in a fraction which appeared to consist of an intact membrane-envelope complex and contained approximately 50% of the cell protein and more than 90% of the ubiquinone and cytochrome A-type mammalian cytochrome
c
oxidase activity. The supernatant fraction, resulting from subsequent centrifugation of the extract at 100,000 ×
g
, contained approximately 50% of the cell protein and more than 80% of the B- and C-type cytochrome and P-463 and the enzymes glutamate dehydrogenase; hydroxylamine dehydrogenase; nitrite synthetase; nitrite reductase; and 2,6-dichlorophenolindophenol-,
p
-phenylenediamine-, pyrogallol-, and hydroquinone-oxidase. Data on the concentration of electron transport components in
Nitrosomonas
are presented.
Structural Genes for Ornithine Transcarbamylase in
Salmonella typhimurium
and
Escherichia coli
K-12
Authors: Syvanen J. Michael , Roth John R.
Published: January 2020

Mutations of
Salmonella typhimurium
affecting the structural gene for ornithine transcarbamylase (
argl
) have been isolated and mapped. The two ornithine transcarbamylase loci in
Escherichia coli
K-12 have been demonstrated by F′ episome transfer.
Osmotic Sensitivity in
Staphylococcus aureus
Induced by Streptomycin
Authors: Wyatt Philip J. , Berkman Richard M. , Phillips David T.
Published: January 2020

Differential light-scattering measurements of
Staphylococcus aureus
cultures were made before and after treatment with streptomycin. Changes were observed in the light-scattering characteristics of streptomycin-treated sensitive cells within 5 min after suspension in a hypotonic solution. No changes were observed with a resistant strain of cells nor with either strain in an isotonic solution. The observed effects occur more slowly when the cells are growing slowly. The physical effects consonant with the changes in the light-scattering curves are a broadening of the cell size distribution, a slight reduction in mean size, and the appearance of clumps or debris. We conclude that streptomycin rapidly alters the selective permeability of the cell membrane and makes the cells susceptible to increased osmotic stresses.
Nature of Col E
1
Plasmid Replication in
Escherichia coli
in the Presence of Chloramphenicol
Authors: Clewell Don B.
Published: January 2020

The colicinogenic factor E
1
(Col E
1
) in
Escherichia coli
continues to replicate by a semiconservative mechanism in the presence of chloramphenicol (CAP) for 10 to 15 hr, long after chromosomal deoxyribonucleic acid (DNA) synthesis has terminated. Following CAP addition, the rate of synthesis of plasmid DNA gradually increases to an extent dependent on the medium employed. Within 2 to 4 hr after the addition of CAP, replication in a glucose-Casamino Acids medium approaches a maximum rate representing approximately eight times an average rate which would be required for a net doubling of DNA per cell in one generation. The number of copies of Col E
1
DNA molecules that accumulate under these conditions approaches about 3,000 copies per cell, representing a 125-fold increase over the normal level of 24 copies per cell. The system is particularly convenient for studying the mechanism of DNA replication.
Changes in Ribonucleic Acid Turnover During Aerobic and Anaerobic Growth in
Rhodopseudomonas spheroides
Authors: Witkin Steven S. , Gibson Kenneth D.
Published: January 2020

Differences in the rate and extent of degradation of ribonucleic acid (RNA) labeled by a 30-sec pulse in aerobically or anaerobically grown
Rhodopseudomonas spheroides
have been studied by using rifampin to block RNA synthesis. In anaerobic cultures, unstable RNA is degraded with a half-life of 1.25 to 2.0 min, and about 40% of the pulse-labeled RNA is stable. In aerobic cultures, the half-life of unstable RNA is increased to 2.5 to 4.0 min, and 50% of the RNA is stable. When aerobic cultures are transferred to anaerobic conditions, there is a rapid drop in half-life and in the proportion of stable RNA. When anaerobic cultures are made aerobic, the reverse changes occur after a lag of about 30 min. Addition of puromycin to either aerobic or anaerobic cultures caused the pulse-labeled RNA to be degraded at the same rate and to the same extent as the RNA in an anaerobic control culture. In contrast, addition of chloramphenicol enhanced the difference in RNA half-life and increased the proportion of stable RNA by about 10% in each case. It is concluded that there is a difference in the stability of an RNA component under aerobic and anaerobic conditions.
Mutation Affecting Plasmolysis in
Escherichia coli
Authors: Wijsman H. J. W.
Published: January 2020

A temperature-sensitive mutant of
Escherichia coli
is described that at the restrictive temperature has lost the ability to plasmolyze. The mutation is located near
pyrF
.
Enzyme Evolution in the
Enterobacteriaceae
Authors: Cocks Gary T. , Wilson Allan C.
Published: January 2020

An immunological approach has been used for the study of alkaline phosphatase evolution in bacteria of the family
Enterobacteriaceae
. Antisera were prepared against alkaline phosphatase from
Escherichia coli
and
Klebsiella aerogenes
and tested against the unpurified alkaline phosphatases of 32 strains of enterobacteria by double diffusion and quantitative micro-complement fixation. The immunological relationships detected among the alkaline phosphatases of enterobacteria agree approximately with those reported for five other enzymes, as well as with the tryptic peptide pattern similarities found for two other enzymes, and with the relationships detected by interspecific deoxyribonucleic acid hybridization tests.
Mutant of
Escherichia coli
K-12 Deficient for Detergent-Resistant Phospholipase A
Authors: Ohki Misao , Doi Osamu , Nojima Shoshichi
Published: January 2020

A mutant deficient for detergent-resistant (DR) phospholipase A was isolated from
Escherichia coli
K-12. Because the enzyme is membrane-bound and the substrate is a lipid, a special procedure was developed for isolating mutants deficient for the enzyme from agar plates. A sodium dodecyl sulfate (SDS)-sensitive mutant was used as a parental strain for the isolation of DR phospholipase A-deficient mutant. Soft agar containing an unsaturated fatty acid auxotroph and SDS was poured over colonies of the parental strain. The cells were easily solubilized with SDS, and phospholipids were efficiently digested by DR phospholipase A from the colonies on an agar plate. Fatty acids released supported the growth of the indicator bacteria. After the cells of the parent were mutagenized with nitrosoguanidine, colonies which could not support the growth of an unsaturated fatty acid auxotroph in the presence of SDS were selected. Four mutants were isolated after in vitro screening of DR phospholipase A activity of 30 halo-less clones. Since an extract of the parent strain mixed with that of a mutant strain was still active, it was concluded that the inability to hydrolyze phospholipids was not due to the accumulation of inhibitory substance; the activity of DR phospholipase A in the mutant was less than 1% of the parental activity. Physiological studies indicated that DR phospholipase A is not essential for the growth of
E. coli
.
Lipid Composition of Growing and Starving Cells of
Arthrobacter crystallopoietes
Authors: Kostiw Luba L. , Boylen C. W. , Tyson B. J.
Published: January 2020

The lipid composition of growing and starving cells of
Arthrobacter crystallopoietes
was compared. Although the lipid composition of the two cell types was similar, the amount of total lipids recovered from the starving cells was 30.4% less than that recovered from the growing cells. The loss of lipids, as compared to the loss of total cell mass during starvation, was (i) proportional to the loss of the cell mass (phosphatidylinositol, phosphatidylglycerol-2, and cardiolipin), (ii) greater than the loss in cell mass (neutral lipids, “glycophospholipids,” and phosphatidic acid), or (iii) less than the loss in cell mass (coenzyme Q, glycolipids, and phosphatidylglycerol-1).
Effects of Proline Analogues on the Formation of Alkaline Phosphatase in
Escherichia coli
Authors: Morris Howard , Schlesinger Milton J.
Published: January 2020

Two of the four proline analogues tested for their effect on the formation and activity of
Escherichia coli
alkaline phosphatase were able to substitute for proline in protein synthesis in a proline auxotroph. One of these, 3,4-dehydroproline, effectively replaced proline and led to formation of an active enzyme under conditions where no proline was present in the polypeptides. Substitution of azetidine-2-carboxylate for proline prevented active enzyme formation, producing instead altered monomeric forms of the alkaline phosphatase. These were detected with antibodies specific to denatured forms of the enzyme, and they were also characterized, together with cellular proteins, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Alkaline phosphatase, as well as several other proteins, is localized exterior to the bacterial cell cytoplasm in the periplasmic space. In the presence of azetidine-2-carboxylate, a substantial number of these periplasmic proteins retain their specific site of localization, and the denatured subunits of alkaline phosphatase were only detected in the periplasmic fraction of the cell. Thus, secretion of these proteins does not appear to require a high degree of specificity in the native structure of the polypeptide chain. The analogues 4-allohydroxyproline and 4-thiazolidine carboxylate were unable to substitute for proline in protein synthesis but they inhibited growth of
E. coli
.
De Novo Biosynthesis of Nicotinamide Adenine Dinucleotide in
Escherichia coli
: Excretion of Quinolinic Acid by Mutants Lacking Quinolinate Phosphoribosyl Transferase
Authors: Chandler Jerry Lr. , Gholson R. K.
Published: January 2020

The excretion of quinolinic acid was studied in growing and resting cells of
Escherichia coli
K-12
nadC
13
. Under optimal conditions, this organism could synthesize quinolinic acid in several-fold excess of the amount which would be required for normal growth. The excretion of quinolinic acid was controlled by the concentration of nicotinamide adenine dinucleotide (NAD) precursors available to the organism either during growth or during incubation in dense cell suspensions. These observations suggest that biosynthesis of NAD de novo is regulated by both repression and feedback inhibition. Analogues of niacin which inhibit bacterial growth also inhibited and repressed the synthesis (excretion) of quinolinic acid. The
p
H optimum for quinolinic acid excretion agreed favorably with the optimum observed for its synthesis in vitro. The rate of quinolinic acid excretion was strongly influenced by the concentration of ribose or glycerol in the medium.
Ecology of Sulfur-Oxidizing Bacteria in Hot Acid Soils
Authors: Fliermans Carl B. , Brock Thomas D.
Published: January 2020

Hot acid soils in Yellowstone National Park are rich in elemental sulfur and harbor extensive populations of sulfur-oxidizing bacteria.
Thiobacillus thiooxidans
is found at temperatures below 55 C, and at temperatures from 55 to 85 C
Sulfolobus acidocaldarius
is present. The distribution of these bacteria as a function of temperature was measured by a most-probable-number dilution method, and their activity in situ was assessed by use of a new technique permitting measurement of
14
CO
2
fixation. From these data it is concluded that sulfur-oxidizing bacteria are responsible for production of sulfuric acid in these acidic thermal habitats. Physical and chemical parameters of this unusual soil habitat were also measured and are described.
Purification and Properties of Nicotinamide Adenine Dinucleotide-Dependent
d
- and
l
-Lactate Dehydrogenases in a Group N Streptococcus
Authors: Mou L. , Mulvena D. P. , Jonas H. A. , Jago G. R.
Published: January 2020

Streptococcus lactis
strain 760, a group N streptococcus, was found to possess nicotinamide adenine dinucleotide-dependent dehydrogenase activities for both the
l
(+) and the
d
(−) isomers of lactic acid. The two enzymes were isolated and purified and were found to differ with respect to
p
H optima, activation by fructose-1,6-diphosphate,
p
H and heat stability, and the temperature at which each enzyme was formed in the organism during growth. The presence of a racemase for lactic acid was not detected by the methods used.
Role of Iron and Sulfur in Pigment and Slime Formation by
Pseudomonas aeruginosa
Authors: Palumbo Samuel A.
Published: January 2020

Media and an analytical scheme have been developed which allow both a qualitative and quantitative estimation of the formation of pyocyanine, related phenazines, pyorubrin, and a blue and a yellow-green fluorescent pigment by
Pseudomonas aeruginosa
. Use of the defined pyocyanine medium of Frank and DeMoss with sulfate or various organic sulfur sources allowed formation of pyocyanine, related phenazines, and pyorubrin. When sulfite was the sulfur source with or without iron,
P. aeruginosa
formed either a yellow-green or a blue fluorescent pigment. Formation of fluorescent pigments of
P. aeruginosa
is related to the ability of sulfite to act as a specific sulfur source. In an investigation of the role of both added iron and sulfur sources, complex patterns of pigment formation were observed. In addition to the fluorescent pigments, sulfite also supported the formation of slime by
P. aeruginosa
.
Cell Wall Alterations Associated with the Hyperproduction of Extracellular Enzymes in
Neurospora crassa
Authors: Gratzner Howard G.
Published: January 2020

A pleiotropic mutation in
Neurospora
(
exo-1
), which confers derepression of α-amylase, glucoamylase, β-fructofuranosidase, and trehalase, appears to also affect the composition of the cell wall. Segregants resulting from the backcross of
exo-1
to the wild-type strain from which it derived are altered in the ratio of galactosamine to glucosamine in hydrolysates of isolated cell walls. Conidial cell walls exhibit a marked decrease in the amount of galactosamine in both
exo-1
and
exo-1
+
strains. Increased levels (approximately sevenfold) of amylase are found in conidia of
exo-1
, as compared with those of
exo-1
+
.
Fate of Transforming Deoxyribonucleic Acid After Uptake by Competent
Bacillus subtilis
: Size and Distribution of the Integrated Donor Segments
Authors: Dubnau D. , Cirigliano C.
Published: January 2020

A series of sheared donor-recipient complex samples were prepared from a competent
Bacillus subtilis
culture which had been transformed by using
3
H,
2
H-labeled deoxyribonucleic acid. Measurement of the molecular weights and buoyant densities of these samples led to the following conclusions. (i) The average size of the single-stranded donor segment which is integrated is 2.8 × 10
6
. (ii) These donor segments are not randomly distributed in the recipient genome, but are clustered in groups, each group containing several discrete donor segments.
Regulation of Histidyl-Transfer Ribonucleic Acid Synthetase Formation in a Histidyl-Transfer Ribonucleic Acid Synthetase Mutant of
Salmonella typhimurium
Authors: McGinnis E. , Williams L. S.
Published: January 2020

Control of formation of the histidyl-transfer ribonucleic acid (tRNA) synthetase with an increased
K
m
for histidine was studied in a
hisS
mutant of
Salmonella typhimurium
. Histidine restriction of both the
hisS
and
hisS
+
strains resulted in a derepression of synthesis of histidyl-tRNA synthetase. When grown in a concentration less than the
K
m
(100 μg/ml) of
l
-histidine, the
hisS
mutant maintained a higher level of histidyl-tRNA synthetase than the
hisS
+
strain. Addition of excess amounts of
l
-histidine to the growth medium of the
hisS
mutant culture grown with 100 μg of
l
-histidine per ml resulted in a repression of histidyl-tRNA synthetase formation to equal that of the
hisS
+
strain grown in 100 μg of
l
-histidine per ml. These data confirm previous findings that histidine tRNA is involved in the repression of synthesis of histidyl-tRNA synthetase.