bluuebunny/crossref_metadata_2025 huggingface dataset:
Properties of Fructose 1,6-Diphosphate Aldolases from Spores and Vegetative Cells ofBacillus cereus
Authors: Sadoff H. L. , Hitchins A. D. , Celikkol Emel
Published: January 2020

Fructose 1,6-diphosphate aldolase from cells ofBacillus cereusappears to be typical Class II aldolase as judged by its functional and physical properties. Spore and vegetative cell aldolase had similar enzymatic, immunochemical, and heat resistance properties in the absence of calcium, but they differed in their thermal stabilities in the presence of calcium, their Stokes' radii, their mobility in acrylamide gel electrophoresis, and their molecular weights. ThepH optimum for both enzymes was 8.5, and theirKmwith respect to substrate was 2 × 10−3m. Highly purified spore and vegetative cell aldolases were both heat labile with half-lives of 4 min at 53 C andpH 6.4. In the presence of 3 × 10−2msolution of calcium ions, the stability of the spore protein increased 12-fold but the vegetative form became more heat labile. The enhanced stability of the spore aldolase was not diminished by dialysis or gel filtration but was lost after chromatography on diethylaminoethyl cellulose atpH 7.4. Aldolase from vegetative cells exists in an equilibrium mixture of two molecular weights, 115,000 and 79,000 in the approximate ratio of 1:4, respectively. The molecular weight of spore aldolase is 44,000. Spore aldolase was more mobile during electrophoresis than its vegetative cell counterpart because of its smaller size.
Synthesis of Protein, Ribonucleic Acid, and Ribosomes by Individual Bacterial Cells in Balanced Growth
Authors: Ecker R. E. , Kokaisl Gloria
Published: January 2020

Relative rates of protein synthesis in individual cells were determined by allowing random populations to incorporate tritiated leucine for very short periods (pulses) and then examining autoradiographs of these cells to assess the amount of incorporation (grains per cell) as a function of cell size. Relative rates of ribonucleic acid (RNA) synthesis were determined in the same way by using tritiated uracil. Unless the uracil pulse was very short (less than 1/20 generation), the RNA labeled during the pulse was predominantly ribosomal. The rate of protein synthesis in individual cells is directly proportional to cell size. The rate of RNA synthesis also increases linearly with size in larger cells, but there appears to be a slight delay in RNA synthesis immediately after cell division. Total cellular content of protein, RNA, and ribosomes is directly proportional to cell size. Thus, we conclude that, in individual cells during the cell cycle (i) the average rate of protein synthesis per ribosome is constant and (ii) the increase in macromolecular mass of the cell is exponential with age.
Membrane Alteration and the Formation of Metachromatic Granules in
Escherichia coli
Treated with
p
-Fluorophenylalanine
Authors: Brostrom Margaret A. , Binkley Stephen B.
Published: January 2020

The effect of
p
-fluorophenylalanine (FPA) on growing cultures of
Escherichia coli
was studied with regard to the composition and morphology of the cell envelope. A cell wall fraction was prepared by autolysis in hypertonic medium, and the resulting spheroplasts were osmotically lysed to obtain a cytoplasmic membrane fraction. Incorporation of labeled phenylalanine, FPA, and
N
-acetylglucosamine into both fractions of FPA-inhibited cells suggested that the composition of the membrane changed with time, whereas that of the cell wall remained relatively constant. Amino acid analysis revealed changes in the composition of the membrane fraction after FPA inhibition. Electron micrographs of shadowed cells and membranes revealed the presence of electron-dense metachromatic granules during the early stages of FPA inhibition.
Microbial Interference Between Indigenous Yeast and Lactobacilli in the Rodent Stomach
Authors: Savage Dwayne C.
Published: January 2020

Indigenous yeasts grow in layers in the mucus on the secreting epithelium of the stomachs of some strains of rats and mice raised under conventional conditions. Likewise, indigenous lactobacilli appear in layers on the nonsecreting epithelium of the stomachs of rats and mice. The two microbial layers can coexist in the same animals. When I gave such rodents penicillin solution in the place of drinking water, the lactobacilli disappeared, and the yeast from the secreting epithelium colonized the nonsecreting epithelium within 24 hr. The yeast remained in layers on the nonsecreting, as well as the secreting epithelium, as long as penicillin was administered. There is no inflammatory reaction or any sign that the yeast invaded below the keratin layer. When the penicillin treatment was discontinued, within 5 to 8 days the indigenous lactobacilli again colonized the nonsecreting epithelium. Concomitantly the yeast was displaced from the keratinized tissue and once more could be found only on the secreting epithelium. Only 2 days were required, however, for the bacteria to recolonize the keratin layer and displace the yeast when the mice were given indigenous lactobacilli in pure culture immediately after the penicillin treatment was discontinued. The lactobacilli must displace the yeast from the nonsecreting epithelium by interfering either with multiplication of the yeast on the tissue or with attachment of the yeast cells to the keratin layer. This interference must proceed continuously during normal life since the yeast never populates the nonsecreting epithelium as long as the lactobacilli are present.
Preparation and Ultrastructure of the Outer Coats of
Azotobacter vinelandii
Cysts
Authors: Lin L. P. , Sadoff H. L.
Published: January 2020

Cysts of
Azotobacter vinelandii
were ruptured with 3.0 m
m
ethylenediaminetetraacetate in 0.05
m
tris(hydroxymethyl)aminomethane buffer (
p
H 7.8) and fractionated by differential centrifugation in density gradients of sucrose or Ficoll (polysucrose) at 10,000 ×
g
for 2 hr at 4 C. The average densities of the cyst exine, the cyst central body, the vegetative cell, and the intact cyst were found to be 1.13, 1.26, 1.28, and 1.31 g/cm
3
in sucrose, and 1.08, 1.12, 1.13, and 1.17 g/cm
3
in Ficoll, respectively. These data were utilized to devise procedures for the isolation of cyst components. Cyst exine appeared as a multilayered structure in ultrathin sections. This same sheetlike structure was seen when exines were subjected to detergent treatment, metal-shadowed, and examined in an electron microscope. The exine was lysed by trypsin and was resistant to lysozyme, indicating that protein may be the principal structural material of the outer cyst coat.
Cation Interactions and Biochemical Composition of the Cell Envelope of a Marine Bacterium
Authors: De Voe Irving W. , Oginsky Evelyn L.
Published: January 2020

Envelopes of a marine isolate, c-A1, and of a terrestrial isolate, 121, were compared for their susceptibility to disintegration in distilled water after exposure to 0.05
m
MgCl
2
and to 0.1 and 1.0
m
NaCl. After exposure to MgCl
2
alone, both types of envelopes remained intact in distilled water. Envelopes of marine isolate c-A1, but not of the terrestrial isolate, fragmented in distilled water after exposure to 1.0
m
NaCl. Partial reaggregation of the c-A1 envelope fragments occurred on addition of MgCl
2
. In cation-exchange experiments, bound Mg
++
in the envelopes of both organisms was displaced by Na
+
. The envelopes of c-A1 were found to contain lipopolysaccharide, muramic acid, and a variety of phospholipids, of which the major component was phosphatidylethanolamine, accompanied by lesser amounts of phosphatidic acid, diphosphatidylglycerol, and phosphatidylserine. Analyses of envelope acid hydrolysates revealed a similar amino acid distribution in the marine and terrestrial isolates, but envelopes of c-A1 had less than half the total amino acid content of envelopes of 121 per envelope dry weight. Possible relationships between cations and biochemical components of the envelopes are considered in terms of differences in behavior of the two organisms in low ionic environments.
Morphological Studies on Relaxed and Contracted Forms of Purified Pyocin Particles
Authors: Higerd Thomas B. , Baechler Charles A. , Berk Richard S.
Published: January 2020

The bacteriocin from
Pseudomonas aeruginosa
, pyocin, consists of a contractile sheath and inner core reminiscent of T-even coliphage tails. Contraction of the outer sheath was found to be promoted by 0.5
m
magnesium chloride, 1% Formalin, low
p
H, sonic treatment, and freezing or thawing or both. The contraction caused by 0.5
m
magnesium chloride, however, was found to be reversible and occurred upon reduction of the salt concentration from 0.5 to 0.02
m
. In addition, direct assay showed that pyocin activity was nearly proportional to the percentage of only uncontracted forms. Initial studies suggested that the adsorption of purified pyocin onto cell wall fragments from the sensitive indicator strain of
P. aeruginosa
occurs with the relaxed particle only and not with the contracted form. However, after adsorption, contraction occurred. Various morphological structures, such as tail fibers and base-platelike appendages, were also observed. Upon contraction, six tail fibers were observed on many particles, four of which appeared to originate from the sheath and two from the inner core. Polysheaths and polycores several hundred nanometers in length were also occasionally observed.
Factors Affecting Transformation of
Micrococcus lysodeikticus
Authors: Kloos Wesley E.
Published: January 2020

Relatively high transfo mation frequencies were obtained with
Micrococcus lysodeikticus
cells, previou[ill]sly grown in defined broth, with a tris(hydroxymethyl)-aminomethane-glutamate b uffer containing Mg
++
, Ca
++
, Ba
++
, or Sr
++
.
Estimate of the Genome Size of Various Microorganisms
Authors: Kingsbury David T.
Published: January 2020

Bacterial genome sizes, determined by deoxyribonucleic acid reassociation kinetics, vary over a 10-fold range. The smallest studied,
Chlamydia trachomatis
, had a genome of 6 × 10
5
nucleotide pairs compared to 4.5 × 10
6
for
Escherichia coli
.
Steady-State Concentrations of Glucose-6-Phosphate, 6-Phosphogluconate, and Reduced Nicotinamide Adenine Dinucleotide Phosphate in Strains of
Escherichia coli
Sensitive and Resistant to Catabolite Repression
Authors: Hsie Abraham W. , Rickenberg H. V. , Schulz Demoy W. , Kirsch Wolff M.
Published: January 2020

No correlation was found between the cellular steady-state concentrations of glucose-6-phosphate, 6-phosphogluconate, and reduced nicotinamide dinucleotide phosphate and resistance versus sensitivity to catabolite repression.
Multivalent Repression of Isoleucine-Valine Biosynthesis in
Saccharomyces cerevisiae
Authors: Magee P. T. , Hereford Lynna M.
Published: January 2020

Regulation of the biosynthesis of four of the five enzymes of the isoleucine-valine pathway was studied in
Saccharomyces cerevisiae
. A method is described for limiting the growth of a leucine auxotroph by using valine as a competitor for the permease. Limitation for isoleucine and valine was accomplished by the use of peptides containing these amino acids conjugated with glycine as nutritional supplements for auxotrophs. The enzymes were repressed on synthetic medium containing isoleucine, valine, and leucine, as well as on broth supplemented with these amino acids. Limitation for any of the three branched-chain amino acids led to derepression of the isoleucine-valine biosynthetic pathway. Maximal derepression ranged from 3-fold for threonine deaminase to approximately 10-fold for acetohydroxyacid synthase. (Two of the enzymes, acetohydroxyacid synthase and dihydroxyacid dehydrase, may be controlled by a mechanism different from that regulating threonine deaminase.) Possible molecular mechanisms for multivalent repression are discussed.
Linked Transformation of Bacterial and Prophage Markers in
Bacillus subtilis
168 Lysogenic for Bacteriophage φ105
Authors: Peterson Anne M. , Rutberg Lars
Published: January 2020

Level of competence reached by
Bacillus subtilis
168 lysogenic for temperate phage φ 105 was reduced compared to that reached by nonlysogenic cells. This effect was probably related to an alteration of the bacterial surface. Deoxyribonucleic acid extracted from φ 105 lysogenic bacteria was used to transform other lysogenic bacteria. About 25% linkage was found between the bacterial
phe-1
marker and prophage marker
ts
N15. The order of a few prophage markers relative to
phe-1
was established in three-factor crosses. The usefulness of this system for a study of the linkage between an integrated prophage genome and that of its host was discussed.
Relations Between Coenzyme A and Presumptive Acyl Carrier Protein in Different Conditions of Streptococcal Growth
Authors: Das D. N. , Toennies G.
Published: January 2020

Exploration of the specific role of cystine in the postexponential growth of
Streptococcus faecalis
led to an inquiry into the fate of cellular coenzyme A (CoA) and acyl carrier protein (ACP), both of which depend for their biosynthesis on cystine and pantothenate as precursors. In
S. faecalis
cells labeled by growth in the presence of
14
C-pantothenate, the label could be separated on the basis of solubility at
p
H 2.1 into two fractions of sharply differing metabolic characteristics. The fractions were not purified, but the soluble
14
C behaved analytically like CoA, and the insoluble
14
C was considered to represent an ACP-like entity on the basis of circumstantial evidence. The fate of these two fractions under various conditions of growth was studied. When the medium contained an excess of the needed precursors, the cellular content of CoA and ACP appeared to remain constant during exponential growth, and in a molar ratio of about 4 CoA to 1 ACP. Cellular ACP, once formed, appeared to be stable under these conditions, but CoA was degraded and replaced at the rate of approximately 20% per division period. With restrictive levels of pantothenate in the medium, initially formed CoA disappeared during growth, as a result, apparently of being converted to ACP. However, when the resulting CoA-depleted cells were returned to a medium containing enough pantothenate, resumption of normal growth was preceded by a lag period, during which rapid conversion of ACP to CoA appeared to take place.
Agglutinating and Bactericidal Properties of Fractions of Rabbit Anti-Vibrio choleraeSerum
Authors: Pike Robert M. , Chandler Cleo H.
Published: January 2020

The major portion of the agglutinating and bactericidal activity of the sera of rabbits immunized with liveVibrio choleraeor with cholera vaccine was found in the γM fractions during the early stages of immunization. After 5 weeks or more, γG fractions accounted for more than half of the agglutinating activity. When late antibody was measured as the amount of protein precipitated by somatic antigens, nearly 3 times as much γG as γM was required for agglutination, and about 30 times as much γG as γM was required to kill 50% of a standard inoculum in the presence of complement. The ratio of vibriocidal to agglutinin titer of γG fractions at different stages of immunization was more variable than that of γM fractions. More complement was required for a vibriocidal effect by γG than by γM. Increasing the amount of complement decreased the amount of both γG and γM required to kill, but smaller amounts of γM required disproportionately larger amounts of complement. Less time was required by γM than by γG to kill 50% of the inoculum. Removal of the group-reactive antibody from anti-Ogawa serum and serum fractions by absorption with Inaba reduced the vibriocidal titer by more than one-half.
Obtention and Assay of Rabbit Anti-
Pseudomonas
Serum
Authors: Laborde Horacio F. , De Fajardo Carmen Legnani
Published: January 2020

Inoculation of rabbits with a nonliving anti-
Pseudomonas
vaccine induced appreciable levels of agglutinating antibodies against strains of
P. aeruginosa
included or not included in the vaccine. Serum obtained from vaccinated rabbits was able to confer temporary protection to mice against challenge with homologous or heterologous strains of
Pseudomonas
. When two or three doses of serum were used, all mice survived the challenge dose for more than 48 hr, but some of the animals died 10 days after challenge. When five doses of serum were used, all mice survived this 10-day period, and even 4 months later they did not show any sign of infection. Serum treatment temporarily inhibited
Pseudomonas
activity and allowed for the activation of the immunogenic mechanisms of the animals. This was corroborated by the fact that mice treated with three doses of serum and surviving the challenge dose for more than 20 days were immune against a second challenge. Anti-
Pseudomonas
gamma globulin conferred a lower degree of protection against homologous or heterologous strains of
Pseudomonas
.
Interaction ofCandida albicanswith Human Leukocytes and Serum
Authors: Lehrer Robert I. , Cline Martin J.
Published: January 2020

A quantitative assay of candidacidal activity based on differential staining of non-viableCandida albicansby methylene blue was developed and applied to studies of leukocytes from normal individuals and patients with fungal and other infections. Serum factors were necessary for optimal phagocytosis ofC. albicansbut lacked direct candidacidal activity. Normal human neutrophils (38 studies) killed 29.0 ± 7.4% of ingestedC. albicansin 1 hr. Eosinophils and monocytes killed a smaller percentage. Neutrophil candidacidal activity did not require protein or ribonucleic acid synthesis by the leukocyte but was inhibited by anaerobic conditions, potassium cyanide, and colchicine. Leukocytes of a patient with hereditary myeloperoxidase deficiency and of three children with chronic granulomatous disease phagocytizedC. albicansnormally, yet failed to kill them. Our data suggest that the neutrophil can play an important role in resistance toCandidainfection and that the lysosomal enzyme myeloperoxidase and its oxidant substrate hydrogen peroxide are the major participants in neutrophil candidacidal activity.
Binding of Rabbit Gamma Globulin by Competent
Bacillus subtilis
Cultures
Authors: Erickson Robert J. , Young Frank E. , Braun Werner
Published: January 2020

Deoxyribonucleic acid (DNA)-mediated transformation of
Bacillus subtilis
can be inhibited by antibodies which specifically interact with single-stranded DNA. This inhibition occurs at a time when the transformation reaction is insensitive to deoxyribonuclease. Studies with radioactive proteins revealed that the maximal binding of gamma globulin occurs immediately preceding the development of maximal competence in the population. Other proteins, such as deoxyribonuclease cytochrome
c
and serum albumin also adsorb to the surface of the cell. After treatment with lysozyme, 67% of the radioactive gamma globulin remains associated with the cytoplasmic membrane. These findings suggest that the DNA is complexed in a deoxyribonuclease-insensitive form to the surface of the cell and is converted to a single-stranded state prior to transport past the membrane and integration into the chromosome.
Zone Electrophoresis of Enzymes in Bacterial Taxonomy
Authors: Baptist James N. , Shaw Charles R. , Mandel Manley
Published: January 2020

The electrophoretic mobilities in starch gels have been determined for eight enzymes in extracts of representative cultures of members of the family
Enterobacteriaceae
. These values were compared with each other and with those obtained from certain bacteria not in this family. The migrations of the eight enzymes were virtually identical for each of eight strains of
Escherichia coli
and for two species of
Shigella
. A number of these enzymes appeared to be identical in other organisms believed to be closely related to
E. coli
(
Salmonella
), and the number of differences increased in organisms which appeared to have lesser degrees of relatedness by other criteria (deoxyribonucleic acid base compositions, overall similarity).
Streptomycin Action: Greater Inhibition of
Escherichia coli
Ribosome Function with Exogenous than with Endogenous Messenger Ribonucleic Acid
Authors: Luzzatto Lucio , Apirion David , Schlessinger David
Published: January 2020

Inhibition of protein synthesis by streptomycin was tested in extracts from a strain of
Escherichia coli
sensitive to streptomycin. Three kinds of messenger ribonucleic acid (RNA) were employed: endogenous cellular RNA, extracted cellular RNA, and phage R17 RNA. Protein synthesis directed by extracted cellular RNA was inhibited three- to fourfold more than protein synthesis directed by endogenous RNA. With R17 RNA as messenger, nearly total inhibition of protein synthesis at initiation was again observed. The greater inhibition of function of extracted RNA, which must initiate new polypeptide chains in vitro, is in accord with the observation that in whole cells streptomycin blocks ribosomes at an early stage in protein synthesis. When streptomycin was added at successively later times during protein synthesis, the subsequent inhibition was progressively less. This was observed with either extracted cellular RNA or phage R17 RNA. A model is presented that can explain the less drastic inhibition by streptomycin of messenger RNA that is already functioning on ribosomes.
Organization of Enzymes in the Polyaromatic Synthetic Pathway: Separability in Bacteria
Authors: Berlyn Mary B. , Giles Norman H.
Published: January 2020

Ultracentrifugation in sucrose density gradients was employed to estimate the molecular weights and to determine possible physical aggregation of the five enzymes catalyzing steps two to six in the prechorismic acid portion of the polyaromatic synthetic pathway in six species of bacteria:
Escherichia coli, Salmonella typhimurium, Aerobacter aerogenes, Bacillus subtilis, Pseudomonas aeruginosa
, and
Streptomyces coelicolor
. The five enzymes were not aggregated in extracts of any of the species examined, nor are the genes encoding these enzymes clustered in those bacterial species for which genetic evidence exists. (An initial examination of the blue-green alga
Anabaena variabilis
indicates nonaggregation in this species also.) This situation in bacteria is in marked contrast to that found in
Neurospora crassa
and other fungi in which the same five enzymes are associated as an aggregate encoded (at least in the case of
N. crassa
) by a cluster of five genes. In addition, also in contrast to
N. crassa
, no evidence was obtained for more than one kind of dehydroquinase activity in any of the bacteria examined. These comparative results are discussed in relation to the origin, evolution, and functional significance of the gene-enzyme relationships existing in the early steps of aromatic biosynthesis in bacteria and fungi.
Inheritance of Mating Fators in Nocardial Recombinants
Authors: Brownell George H. , Kelly Karol L.
Published: January 2020

The segregation of mating loci with other unselected genes was analyzed in recombinants obtained from matings of
Nocardia canicruria
and
N. erythropolis
. The loci
C/c
and
E/e
control nocardial compatibility. Four mating genotype combinations were observed:
cE, Ce, CE
, and
ce
. Strains of
N. erythropolis
bear the genotype
cE
and strains of
N. canicruria
bear the
Ce
alleles. The
CE
recombinant mating type is capable of mating with both organisms, whereas the
ce
-containing recombinant is nonfertile. The
E
locus was found to segregate with
StrA1
(streptomycin-resistance gene) on the
N. erythropolis
linkage group. The
C
locus appeared linked to
PurB2
(purine-requiring gene) on the
N. canicruria
linkage group. A few observed recombinants were capable of further segregation of unselected characters after colonial purification, suggesting a possible heterogenomic condition or multiple rounds of mating. Prior treatment of recombinants with acriflavine failed to alter their compatibility or the frequency at which recombinants were recovered. The segregation pattern of the mating loci allowed for specific recombinant class types to be compatible.
Expression of the Arginine Regulon of
Escherichia coli
W: Evidence for a Second Regulatory Gene
Authors: Theil Elizabeth C. , Forsyth George W. , Jones Evan E.
Published: January 2020

Effect of the
M
(modifier) gene of
Escherichia coli
W on the expression of wild-type structural genes of four arginine biosynthetic enzymes was studied by examining enzyme activity in cell-free extracts of cultures grown in minimal medium and medium containing arginine. The mutant
M
gene was originally identified as causing arginine-induced synthesis of acetylornithine δ-transaminase in a strain deficient for the enzyme. The strains used in this study received the mutant
M
gene by recombination. Noncoordinate repression has been demonstrated for two more enzymes of the arginine regulon of
E. coli
W and the
M
−
gene increases the degree of noncoordinate repression for the regulon. Mutation of the
M
gene results in altered regulation of acetylornithine δ-transaminase, ornithine transcarbamylase, and acetylornithinase. In addition, a decreased growth rate is observed. It is proposed that the
M
gene is a regulatory gene. A model is presented to explain the data which involves changes in operator-repressor affinity for the structural genes and possibly for the gene controlling arginyl transfer ribonucleic acid synthetase.
Protein Specificity and Sexual Morphogenesis in
Schizophyllum commune
Authors: Wang Chiu-Sheng , Raper John R.
Published: January 2020

Soluble proteins of a number of strains of the basidiomycete
Schizophyllum commune
were separated on polyacrylamide gel by disc electrophoresis. The presence or absence,

R
F

values, and relative intensity of protein bands, observed on gel columns and densitometric tracings, were used as criteria for analysis and comparison. Eight mycelial types were studied, namely, normal homokaryon, dikaryon, homokaryons carrying primary mutation(s) at one or both of the
Aβ
and
Bβ
loci, and three mutant
B
homokaryons, each carrying a different type of modifier mutation. Similarities and dissimilarities in protein spectra among these mycelial types, observed with crude extracts, “total protein precipitates,” and protein fractions, were consistent with predictions based on an earlier genetic model for the action of the two incompatibility factors known to control “sexual morphogenesis” in this fungus.
Phospholipid Composition of
Bacillus subtilis
Authors: den Kamp J. A. F. Op , Redai I. , van Deenen L. L. M.
Published: January 2020

Bacillus subtilis
contained at least five phospholipids, four of which have been isolated and identified as a polyglycerol phospholipid, probably cardiolipin, phosphatidylglycerol, phosphatidylethanolamine, and lysylphosphatidylglycerol. Further purification of the latter phosphoglyceride was obtained by high-voltage electrophoresis, and it was shown that this treatment removed amino acid-containing, nonlipidic material from the phosphoglyceride. This associated material, which is not covalently linked to the lipid, gave rise to minor amounts of a number of amino acids, other than lysine, in acid hydrolysates of the lysylphosphatidylglycerol. The phospholipid composition of
B. subtilis
appeared to depend on the growth conditions. Addition of glucose to the medium lowered the
p
H during growth; this was accompanied by an increase in the amount of lysylphosphatidylglycerol and a decrease in the phosphatidylglycerol content, when compared with growth at neutral
p
H. The amount of the other phospholipids and the total amount of phospholipid remained constant under the different conditions. The shape and the osmotic susceptibility of the protoplasts of this organism appeared to depend on the growth conditions. Cells harvested from a neutral growth medium gave spherical protoplasts which lysed rapidly, whereas cells grown in an acidic medium maintained their rod-shaped form to a great extent after the cell wall had been removed, even after being suspended in a hypotonic medium. The latter observation suggests the presence of a more rigid membranous structure in cells which have been exposed to a low environmental
p
H during growth.
Genetic Transfer of the Vi Antigen fromSalmonella typhosatoEscherichia coli
Authors: Johnson E. M. , Baron L. S.
Published: January 2020

The Vi antigen was expressed in a strain ofEscherichia coliafter transfer of theviaB locus from aSalmonella typhosaHfr donor.
Occult Endotoxin in Bacterial Protoplasm
Authors: Rudbach Jon A. , Milner Kelsey C. , Ribi Edgar
Published: January 2020

Protoplasm separated from disrupted cells of gram-negative bacteria was extracted with hot phenol-water or was precipitated with ethyl alcohol after digestion with Pronase. These methods recovered about 10 times more endotoxin than was detectable in the untreated protoplasm. Inactivation of endotoxin by protoplasm also occurred in vitro when the endotoxin was first dissociated into subunits before reaction with protoplasm. Despite this increased yield from another source, the major proportion of endotoxin was still found in the cell walls.
Conditions for Competence in the
Bacillus licheniformis
Transformation System
Authors: Spizizen John , Prestidge Louise
Published: January 2020

Some variables in the
Bacillus licheniformis
transformation system, such as inoculum size, initial cell density in transformation medium, and time of optimal competence, have been explored, and a methodology has been developed to obtain greater reproducibility and maximal competence for transformation. The transformation system in
B. licheniformis
has been shown to be similar to that of
B. subtilis
in a number of respects, including “dormancy” of transformed cells and the concentration of transforming deoxyribonucleic acid required for saturation.
Immunological Response of Three Mouse Strains to Typhoid Vaccine and Vi Antigen
Authors: Esposito Vito M. , Feeley John C. , Leeder Wayne D. , Pittman Margaret
Published: January 2020

Vi-agglutinin, active cutaneous anaphylaxis and protective responses (ed50) of three mouse strains (CFW, NIH, and Balb/cAnN) to acetone-inactivated typhoid vaccine and soluble Vi antigen were compared. Seven days after immunization with either typhoid vaccine or Vi antigen the three strains of mice differed with respect to Vi-antibody titers. Significant differences were observed in the protective responses. Each mouse strain was significantly better protected by the intraperitoneal than by subcutaneous route of immunization. Active cutaneous anaphylaxis was more pronounced in showing strain differences in response to Vi antigen. The serological responses to Vi antigen of the strains of mice did not correlate with their protective response.
Fidelity of Initiation of Protein Synthesis After Premature Chain Termination in Polarity Mutants
Authors: Parsons S. J. , Burns R. O.
Published: January 2020

β-Isopropylmalate dehydrogenase, the product of the second cistron of the leucine operon in
Salmonella typhimurium
, produced by strains bearing nonsense or frameshift mutations in the first cistron of the operon was shown to be homogeneous as judged by electrophoretic and immunological techniques. Amino terminal analyses suggest that the enzyme produced by the mutant strains is identical with the wild-type enzyme. This view is supported by the observation that a nonsense mutant strain β-isopropylmalate dehydrogenase copurifies with the wild-type enzyme. The results suggest that the uncoupling of normal chain termination and reinitiation does not interfere with the fidelity of subsequent polypeptide chain initiation in a polycistronic messenger ribonucleic acid.
Antifungal Effects of Peroxidase Systems
Authors: Lehrer R. I.
Published: January 2020

In the presence of hydrogen peroxide and either potassium iodide, sodium chloride, or potassium bromide, purified human myeloperoxidase was rapidly lethal to several species ofCandida. Its candidacidal activity was inhibited by cyanide, fluoride, and azide, and by heat inactivation of the enzyme. A hydrogen peroxidegenerating system consisting ofd-amino acid oxidase, flavine-adenine dinucleotide, andd-alanine could replace hydrogen peroxide in the candidacidal system. Horseradish peroxidase and human eosinophil granules also exerted candidacidal activity in the presence of iodide and hydrogen peroxide; however, unlike myeloperoxidase or neutrophil granules, these peroxidase sources were inactive when chloride replaced iodide. Cells ofSaccharomyces, Geotrichum, andRhodotorulaspecies, and spores ofAspergillus fumigatusandA. nigerwere also killed by the combination of myeloperoxidase, iodide, and hydrogen peroxide. Peroxidases, functionally linked to hydrogen peroxide-generating systems, could provide phagocytic cells with the ability to kill many fungal species.
Fatty-Acid Composition of
Candida utilis
as Affected by Growth Temperature and Dissolved-Oxygen Tension
Authors: Brown C. M. , Rose A. H.
Published: January 2020

Analyses were made of the fatty-acid composition of
Candida utilis
NCYC 321 grown in a chemostat at a dilution rate (equal to growth rate) of 0.1 hr
−1
and at temperatures in the range of 30 to 15 C and dissolved oxygen tensions between 75 and <1 mm of Hg. Cells grown under glucose limitation or NH
4
+
limitation contained mainly C
16:0
, C
16:1
, C
18:0
, C
18:1
, C
18:2
, and C
18:3
acids as detected by gas-liquid chromatography of methyl esters of the acids from lipids extracted with chloroform-methanol. The relative proportions of these acids varied with the growth temperature and the dissolved-oxygen tension in the culture. A decrease in growth temperature from 30 to 20 C led to an increased synthesis of unsaturated acids in cells grown under either limitation at a fixed-oxygen tension in the range of 75 to 5 mm of Hg. In cultures with a dissolved-oxygen tension of 1 and <1 mm of Hg, a further decrease in temperature to 15 C caused an increased synthesis of unsaturated fatty acids. A decrease in dissolved-oxygen tension led to a diminished synthesis of unsaturated fatty acids in cells grown at a fixed temperature under either limitation. Cells grown at a fixed temperature under glucose limitation synthesized a greater proportion of C
16
acids at the expense of C
18
acids as the dissolved oxygen tension was decreased from 75 to <1 mm of Hg. A preferential synthesis of C
16
acids also occurred as the growth temperature was decreased from 30 to 15 C in cells grown under glucose limitation at a fixed-oxygen tension. The same effect was observed in cells grown under NH
4
+
limitation when the temperature was lowered from 30 to 20 C; but when the temperature was decreased further to 15 C, the cells synthesized a slightly greater proportion of C
18
acids. Synthesis of a large proportion of C
16
acids was accompanied by an excretion of pyruvate, and occasionally traces of 2-ketoglutarate, and an increased intracellular accumulation of certain amino acids.
Role of Sodium in Determining Alternate Pathways of Aerobic Citrate Catabolism in
Aerobacter aerogenes
Authors: O'Brien R. W. , Stern Joseph R.
Published: January 2020

In contrast to the absolute Na
+
requirement for anaerobic growth of
Aerobacter aerogenes
on citrate as sole carbon source, aerobic growth of this microorganism did not require the presence of Na
+
. However, Na
+
(optimal concentration, 10 m
m
) did increase the maximal amount of aerobic growth by 60%, even though it did not change the rate of growth. This increase in growth was specifically affected by Na
+
, which could not be replaced by K
+
, NH
4
+
, Li
+
, Rb
+
, or Cs
+
. Enzyme profiles were determined in
A. aerogenes
cells grown aerobically on citrate in media of varying cationic composition. Cells grown in Na
+
-free medium possessed all the enzymes of the citric acid cycle including α-ketoglutarate dehydrogenase, which is repressed by anaerobic conditions of growth. The enzymes of the anaerobic citrate fermentation pathway, citritase and oxalacetate decarboxylase, were also present in these cells, but this pathway of citrate catabolism was effectively blocked by the absence of Na
+
, which is essential for the activation of the oxalacetate decarboxylase step. Thus, in Na
+
-free medium, aerobic citrate catabolism proceeded solely via the citric acid cycle. Addition of 10 m
m
Na
+
to the aerobic citrate medium resulted in the activation of oxalacetate decarboxylase and the repression of α-ketoglutarate dehydrogenase, thereby diverting citrate catabolism from the (aerobic) citric acid cycle mechanism to the fermentation mechanism characteristic of anaerobic growth. The further addition of 2% potassium acetate to the medium caused repression of citritase and derepression of α-ketoglutarate dehydrogenase, switching citrate catabolism back into the citric acid cycle.
Enzymatic Analysis of the Requirement for Sodium in Aerobic Growth of
Salmonella typhimurium
on Citrate
Authors: O'Brien R. W. , Frost G. M. , Stern Joseph R.
Published: January 2020

Na
+
was required for the aerobic growth of
Salmonella typhimurium
on citrate, but not on
l
-malate, glucose, or glycerol. The maximal growth rate and the maximal total growth occurred with 6 to 7 m
m
Na
+
. Na
+
could not be replaced by K
+
, NH
4
+
, Li
+
, Rb
+
, or Cs
+
. Sonically treated extracts of citrate-grown cells contained the enzymes of the citrate fermentation pathway (citritase and oxalacetate decarboxylase) and all of the enzymes of the citric acid cycle. Thus, two separate routes of citrate catabolism appeared to be operational in the cells. Two discrete oxalacetate (OAA) decarboxylases were also demonstrated. One was of the “classic” type, being activated by Mn
++
and inhibited by ethylenediaminetetracetate (EDTA). It was present in the cell sap. The second decarboxylase closely resembled the Na
+
-activated OAA decarboxylase of citrate-grown
Aerobacter aerogenes
, whose growth also requires, or is increased, by Na
+
. This decarboxylase was EDTA-insensitive, specifically activated by Na
+
and inhibited by avidin, and it had a high affinity for OAA. It was induced by growth on citrate, but not
l
-malate or glycerol. It is suggested that the Na
+
requirement for growth reflects the need to activate this OAA decarboxylase as a component of the citrate fermentation pathway and that citrate catabolism via the citric acid cycle, which should be independent of Na
+
, is somehow dependent upon the activity of the Na
+
-activated enzyme.
Phospho-β-glucosidases and β-Glucoside Permeases in
Streptococcus, Bacillus
, and
Staphylococcus
Authors: Schaefler S. , Malamy A. , Green I.
Published: January 2020

The presence of phospho-β-glucosidases and β-glucoside permeases was found in strains of
Streptococcus, Bacillus
, and
Staphylococcus
. In streptococci, the phospho-β-glucosidase activity depends on the antigenic group. The highest activity was found in strains of group D. In group D strains, phospho-β-glucosidase activity is induced by β-methyl glucoside and cellobiose but not by thiophenyl β-glucoside (TPG). With the exception of four strains isolated in Japan, all strains of
B. subtilis
tested possess an inducible phospho-β-glucosidase activity, β-methyl glucoside, cellobiose, and TPG acting as inducers.
S. aureus
strains possess phospho-β-glucosidase A but not phospho-β-glucosidase B, whereas most
S. albus
strains show no detectable phospho-β-glucosidase activity. The prompt fermentation of β-methyl glucoside by
S. aureus
strains could serve as an additional criterion for their differentiation from
S. albus
. A comparative investigation of the active uptake of
14
C-TPG showed that a
Streptococcus
group D strain and a
B. subtilis
strain posses two inducible permeases with characteristics similar to the β-glucoside permeases I and II of
Enterobacteriaceae
. In
S. aureus
, TPG is accumulated by a constitutive permease with high affinity for aromatic β-glucosides and glucose. The active uptake of TPG by
S. aureus
appears to depend on the activity of the phosphoenol pyruvate-dependent phosphotransferase system.
Biosynthesis of Ubiquinone in
Escherichia coli
K-12: Location of Genes Affecting the Metabolism of 3-Octaprenyl-4-hydroxybenzoic Acid and 2-Octaprenylphenol
Authors: Cox G. B. , Young I. G. , McCann L. M. , Gibson F.
Published: January 2020

Two genes (
ubiB
and
ubiD
) concerned with two successive reactions in ubiquinone biosynthesis in
Escherichia coli
were mapped and found to be closely linked. Mutant strains of
E. coli
carrying the
ubiB
−
and
ubiD
−
alleles were shown to accumulate 2-octaprenylphenol and 3-octaprenyl-4-hydroxybenzoic acid, respectively. These compounds were isolated and identified by using nuclear magnetic resonance and mass and infrared spectroscopy. Cell extracts from the mutant strain carrying the
ubiD
−
allele lack 3-octaprenyl-4-hydroxybenzoate decarboxylase activity.
Correlation Between Growth Inhibition and the Binding of Various Penicillins and Cephalosporins to
Staphylococcus aureus
Authors: Edwards John R. , Park James T.
Published: January 2020

The concentration of penicillin (or cephalosporin) required to achieve a given rate of binding to
Staphylococcus aureus
H correlates well with that required for inhibition of growth. This result suggests that the irreversible binding of penicillins and cephalosporins to cells is responsible for their biological activity.
Effect of Temperature on Survival of Airborne
Mycoplasma pneumoniae
Authors: Wright D. N. , Bailey G. D. , Goldberg L. J.
Published: January 2020

Aerosols of
Mycoplasma pneumoniae
were prepared at each of eight relative humidities between 0 and 85% and at five separate temperatures between 10 and 43 C. Survival of these organisms was found to be a function of both relative humidity and temperature. However, the temperature response was mediated by humidity in that the effects of temperature could be observed only if some water vapor was present. At all temperatures, survival of
M. pneumoniae
in aerosols was found to be best at the extremes of relative humidity. The effects of temperature were such that irrespective of relative humidity an increase in temperature resulted in a decreased airborne survival time.
Tumor Growth Complementation Among Strains of
Agrobacterium
Authors: Lippincott James A. , Lippincott Barbara B.
Published: January 2020

The ability of 31 strains of
Agrobacterium
to initiate the production of a tumor growth factor (TGF) which is associated with crown-gall tumors on primary pinto bean leaves was determined. Extracts from bean leaves inoculated with these bacteria were tested and they showed that 16 of the 19 strains that induced tumors on the leaves also initiated TGF production. The three strains for which no TGF was detected were of low infectivity and included two strains of
A. tumefaciens
and a strain of
A. rhizogenes
. Five of the 12 strains that did not induce pinto bean leaf tumors were found to initiate TGF production. Representatives of
A. tumefaciens, A. rhizogenes
, and
A. radiobacter
among these 12 strains were present in both categories. Mixed inocula composed of one of the three infectious TGF-negative strains and one of the five nontumorigenic TGF-positive strains resulted in increased growth of tumors induced by the former. These growth changes were not correlated with changes in tumor number. The ability of different strains to show these tumor growth complementation effects corresponded fully with their ability to initiate TGF, as determined by the assay of leaf extracts. The nontumorigenic TGF-positive strains also promoted the growth of tumors initiated by low concentrations of strain B6. These complementation effects were due, therefore, to the same TGF found in extracts of B6 inoculated leaves and of leaves inoculated with most tumorigenic as well as many nontumorigenic strains of
Agrobacterium
. Heat-inactivated cells of strain B6 failed to initiate sufficient TGF to be detected in extracts, and heat-inactivated cells of several strains failed to show tumor growth complementation, indicating bacterial viability to be one prerequisite for TGF initiation. Heat inactivated cells also inhibited TGF production by viable cells, similar to their ability to inhibit tumor initiation. Consequently, bacteria capable of attaching to the
A. tumefaciens
infection site may initiate one of four patterns of events: (i) TGF production only, (ii) tumor induction only, (iii) both, or (iv) neither. Suggestive evidence for a second tumor-associated growth factor is presented.
Influence of O Side Chains on the Attachment of the Felix O-1 Bacteriophage to Salmonella Bacteria
Authors: Lindberg A. A. , Holme T.
Published: January 2020

The adsorption rate constant (ARC) of the Felix O-1 (FO) bacteriophage to sensitive
Salmonella
strains was used to determine the effect of variations in surface antigens on phage attachment. The
N
-acetylglucosamine of the common-core polysaccharide of the
Salmonella
lipopolysaccharide (LPS) was found to be an essential part of the receptor for the FO phage in conformation with earlier reports. It was found that (i) the ARC was low for strains having O side chains containing two or three non core monosaccharides, (ii) the ARC varied when the O side chain contained no, or only one, noncore monosaccharide, (iii) the ARC was high when the O side chain contained only one repeating unit, and (iv) the ARC was high to mutants of chemotype Ra in which the
N
-acetylglucosamine was the terminal sugar of the LPS. Since a good correlation was found between the ARC of the FO phage and the phage-inactivating capacity of phenol water-extracted LPS, the results suggest that only the structure and composition of the LPS determines the adsorption rate of the FO phage. The phage-inactivating capacity of LPS from the Ra mutants increased in parallel with higher glucosamine contents in the core polysaccharide. In smooth strains having long and numerous O side chains, the access of the FO phage to its receptor is probably blocked by the presence of the side chains, whereas short and numerous side chains or T1 side chains do not interfere with the FO attachment.
Genetic and Biochemical Studies of Partially Active Tryptophan Synthetase Mutants of
Saccharomyces cerevisiae
Authors: Manney Thomas R. , Duntze Wolfgang , Janosko Nancy , Salazar Jorge
Published: January 2020

Approximately 20% of the tryptophan synthetase mutants (
tr
5
) of
Saccharomyces cerevisiae
retain activity in one of the half reactions catalyzed by this enzyme and have been identified as indole-accumulating or indole-utilizing
tr
5
mutants by complementation tests. Ten indole-accumulating and six indole-utilizing mutants have been studied. For the half reactions they catalyze, these partially active mutants have from about one-half to twice the specific activities of the wild-type enzyme. Indole-accumulating mutant enzymes showed varying responses to pyridoxal phosphate and serine in the assay mixture. The partially active mutants were further characterized by their patterns of allelic complementation and their distribution on the fine-structure map of the locus. It was concluded that these mutants define two distinct functional regions of the
tr
5
locus, corresponding to the two half reactions.