bluuebunny/crossref_metadata_2025 huggingface dataset:
Deoxyribonucleic Acid Base Composition in the Taxonomy of
Staphylococcus
Authors: Garrity Francis L. , Detrick Barbara , Kennedy E. R.
Published: January 2020

Twenty-four strains of
Staphylococcus aureus
, including eight known mutants of
S. aureus
and strains growing under a variety of environmental conditions or exposed to a number of physical and chemical agents, maintained a remarkably narrow range of guanine plus cytosine (GC) content (32.4 to 35.1%). The wide range of GC content (30.7 to 40%) reported in the literature was due to the variety of methods and calculations used rather than to any substantial variation in base composition. The UV-2 “mutant” (ATCC 13680) with a GC content of 67.6% reported to be derived from
S. aureus
(ATCC 13679) was a species of
Corynebacterium
. The data presented were consistent with the concept that base composition changes only to a very slight degree by mutation.
Determination and Analysis ofActinomyces israeliiSerotypes by Fluorescent-Antibody Procedures
Authors: Brock Darrell W. , Georg Lucille K.
Published: January 2020

This study was undertaken to determine the antigenic relationships between serotypes ofActinomyces israeliiwith fluorescent-antibody (FA) procedures. In addition, the antigenic relationships betweenA. israeliiand other members of the genusActinomyceswere studied by the same methods. Seven FA conjugates were used to determine the serological characteristics of 28 isolates believed to representA. israelii, serotypes 1 and 2. The results showed that the lower dilutions of serotype 1 conjugates stained serotype 2 antigens; however, serotype 2 conjugates did not stain serotype 1 antigens. Serotype 1 conjugate could be made specific by adsorption.A. israeliiserotype 1 conjugate cross-reacted also withA. naeslundii, but this cross-reaction could be eliminated by adsorption or dilution. Serotype 2 conjugate appeared to be specific forA. israeliiserotype 2. Adsorption studies revealed antigenic variants among the variousA. israeliiserotype 1 and 2 isolates. However, all isolates could be identified by direct FA staining with appropriate conjugates. One isolate previously identified asA. israeliiwas shown, on the basis of FA studies, to be anA. naeslundii. A polyvalent diagnostic reagent was prepared which was specific forA. israeliiserotypes 1 and 2. This reagent should find application in diagnostic and reference laboratories.
Characterization of
Actinomyces israelii
Serotypes 1 and 2
Authors: Brock Darrell W. , Georg Lucille K.
Published: January 2020

In a previous serological study, we compared 14 isolates of
Actinomyces israelii
serotype 2 with 13 serotype 1 cultures. The present study reports the morphological, physiological, and biochemical characteristics of these same 27 cultures. All of the isolates exhibited similar cellular morphology, and all but one produced the typical spider type microcolony on solid media. Twelve of 13 serotype 1 isolates produced the molar tooth type macrocolony, whereas only 2 of 14 serotype 2 cultures produced this type of rough colony. All of the serotype 1 isolates fermented arabinose with the production of acid; none of the serotype 2 cultures fermented this carbohydrate. All 27 cultures produced the greatest amount of growth when cultured under anaerobic conditions and grew poorly or not at all in air. Both groups of organisms produced similar reactions on other biochemical test media; these findings suggested that
A. israelii
serotype 2 should not be given a species designation.
Synergistic and Product Induction of the Enzymes of Tryptophan Metabolism in
Pseudomonas acidovorans
Authors: Rosenfeld Henry , Feigelson Philip
Published: January 2020

The process of induction of tryptophan oxygenase in
Pseudomonas acidovorans
is typical of many microbial enzyme induction systems, in that it (i) requires cell multiplication and de novo protein synthesis, (ii) is subject to catabolite repression, (iii) results in the formation of a stable enzyme, whose level, upon removal of inducer, is diluted out by cell proliferation, and (iv) exhibits product induction.
l
-Kynurenine was more effective than
l
-tryptophan as an inducer of both tryptophan oxygenase and the second enzyme of the pathway, kynurenine formamidase. The occurrence of product induction of these two enzymes by their common metabolite eliminated the possibility of sequential induction of these enzymes.
dl
-5-Fluorotryptophan, nonmetabolizable and devoid of any inducing activity, resulted in a concentration-dependent inhibition of the
l
-tryptophan-mediated induction of tryptophan oxygenase; kynurenine formamidase induction, however, was not influenced by the presence of
dl
-5-fluorotryptophan.
dl
-7-Azatryptophan, also nonmetabolizable and completely inactive as an inducer, acted synergistically with
l
-tryptophan and superinduced tryptophan oxygenase levels. When induction was conducted in a medium containing only
l
-tryptophan and 7-azatryptophan as inducing agents, then tryptophan oxygenase induction was enhanced, whereas the kynurenine formamidase level was essentially unchanged. These data indicate that various inducing conditions affect the relative proportions of tryptophan oxygenase and kynurenine formamidase, and thus indicate noncoordinate regulation of these enzyme activities.
Permeability of
Serratia marcescens
to Some Inorganic Salts
Authors: Zimmerman Leonard
Published: January 2020

The physical interactions between
Serratia marcescens
and solutions of NaCl, CaCl
2
, CaI
2
, NaI, and Na
2
HPO
4
plus NaH
2
PO
4
were examined. Dilute (0.017
n
) salt solutions did not cause cells to lose water, as evidenced by the unchanged weight of centrifugally packed cells. The cells preferentially adsorbed the cations and repelled the anions of most salts in these solutions. Concentrated (1.71
n
) salt solutions markedly reduced the weight and water content of centrifugally packed cells, although these cells took up considerable amounts of salts. More than 90% of the water in the packed-cell pellets was available for the solution of NaCl at 4.2 to 4.4% concentration. The observation that salts apparently penetrated the cells freely and yet caused extensive dehydration was not readily compatible with conventional concepts of solute-induced plasmolysis. Alternative hypotheses to explain the data included the following. First, the cells lost weight and water to concentrated salt solutions through a nonosmotic competitive dehydration, causing a shrinkage of the protoplasmic gel. The shrinkage of the cell wall was limited because of the rigidity of its mucopeptide layer; therefore, a space appeared between the cell wall and the cell membrane. Second, cells may have equilibrated their water activity with that of their environment by two mechanisms: (i) the loss of water by plasmolysis or competitive dehydration, and (ii) alterations in cell permeability that admitted previously excluded solutes to the cell interior. Possibly, the correct explanation of the observations reported here involves elements of all three hypotheses, plasmolysis, competitive dehydration, and permeability alterations.
Association of Microcyst Formation in
Spirillum itersonii
with the Spontaneous Induction of a Defective Bacteriophage
Authors: Clark-Walker G. D.
Published: January 2020

Mitomycin C and ultraviolet light were found to induce the formation of microcysts in
Spirillum itersonii
. These forms, as well as spontaneously occurring microcysts in this species, were found to contain phage tail parts, rhapidosomes, and a granular substance not seen in normal cells. It is suggested that microcysts are formed as the result of the induction of a defective phage. The production of phage lysozyme within the cell could lead to the formation of spherical forms as the cells lose their structural mucopeptide layer. Complete virus particles were not seen, nor was any biological activity demonstrated when the induced cultures were tested against two other strains of
S. itersonii
. The other strains of this bacterium also formed microcysts and phage tail parts when induced with mitomycin. Attempts to isolate an organism lacking the defective phage have been unsuccessful.
Antigens of
Neisseria gonorrhoeae
: Characterization by Gel Filtration, Complement Fixation, and Agar-Gel Diffusion of Antigens of Gonococcal Protoplasm
Authors: Danielsson Dan G. , Schmale John D. , Peacock William L. , Thayer James D.
Published: January 2020

With the use of the agar-gel-diffusion and complement-fixation techniques, it was shown that protoplasm from different gonococcal isolates reacted with sera from some humans with a history of gonorrhea but did not react with “normal” human sera. The reactive antigen(s) could be partially separated from the other antigens by passing the gonococcal protoplasm through Sephadex G-200. The antigen(s) reacting in the gel-diffusion and complement-fixation tests appeared in the same fraction. On the basis of Sephadex gel filtration, the molecular weight of this antigen(s) is probably greater than 200,000.
Ocular Lesions Induced by the Trachoma Agent in Rabbits
Authors: Oh J. O. , Tarizzo M. L.
Published: January 2020

Injection of the T'ang strain of trachoma agent into the anterior chamber of the rabbit eye caused corneal opacity, characteristic microscopic lesions of the corneal endothelium, varying degrees of neovascularization of the cornea, and uveitis. These ocular changes were agent-specific. The experimental data showed that the microorganism developed in the ocular tissues. The results of this study suggest the possibility of using the rabbit eye as an experimental model for the study of trachoma.
Acetylglucosaminidase, an Early Enzyme in the Development of
Dictyostelium discoideum
Authors: Loomis William F.
Published: January 2020

The specific activity of acetylglucosaminidase has been found to increase more than 10-fold during the first 10 hr of development in the cellular slime mold
Dictyostelium discoideum
. The specific activity then remained essentially constant until after germination. The activity was purified 36-fold and found to behave as a single protein species. The increase in specific activity required concomitant protein synthesis. If ribonucleic acid synthesis was preferentially inhibited during the period of synthesis of acetylglucosaminidase, further increase in enzymatic activity stopped after 2 hr. The increase in activity did not occur in a mutant strain which did not undergo the first step in morphogenesis. Mutant strains, blocked slightly later in morphogenesis, synthesized the enzyme at the normal rate but for an extended period. It was concluded that the initiation and termination of synthesis of acetylglucosaminidase are controlled by the developmental program.
Staphylococcal Acid Phosphatase: Preliminary Physical and Chemical Characterization of the Loosely Bound Enzyme
Authors: Malveaux F. J. , Clemente C. L. San
Published: January 2020

At temperatures between 45 and 50 C, staphylococcal acid phosphatase purified 44-fold had maximal activity at
p
H 5.2 to 5.3. However, the enzyme was most stable in the alkaline range (
p
H 8.5 to 9.5) at temperatures below 50 C. Iodoacetate and ethylenediamine-tetraacetic acid were effective inhibitors, whereas mercaptoethanol and Cu
2+
acted as stimulators. The energy of activation for hydrolytic cleavage of the synthetic substrate,
p
-nitrophenyl phosphate, was 19.5 Kcal/mole.
K
m
for the same substrate was 4.5 × 10
−4
m
. The purified enzyme was most active against the substrates
p
-nitrophenyl phosphate and glyceraldehyde 3-phosphate.
Regulator Gene Controlling Enzymes Concerned in Tyrosine Biosynthesis in
Escherichia coli
Authors: Wallace B. J. , Pittard James
Published: January 2020

Mutants of
Escherichia coli
K-12 have been isolated in which several enzymes concerned with tyrosine biosynthesis are derepressed. These mutants were obtained from a parent strain possessing only a single 3-deoxy-
d
-arabinoheptulosonic acid-7-phosphate (DAHP) synthetase isoenzyme, DAHP synthetase (tyr), by selecting for resistance to the tyrosine analogue, 4-aminophenylalanine. The mutation responsible for this derepression has been mapped and the gene, which is not closely linked to
aroF
and
tyrA
, has been designated
tyrR
.
Autoregulation of the Synthesis of Nitrate Reductase in
Aspergillus nidulans
Authors: Cove D. J. , Pateman J. A.
Published: January 2020

In
Aspergillus nidulans
, the syntheses of nitrate and nitrite reductases are induced by nitrate, and are repressed by ammonium. It is possible in wild-type strains to overcome partially the repressive effect of ammonium, by the addition of high concentrations of nitrate to the growth medium. Mutations which lead to the production of abnormal nitrate reductase affect in addition the control of the synthesis of the nitrate-metabolizing enzymes, which in these strains are produced constitutively. That this is not due to the accumulation of an internal inducer has now been shown, as these mutants have been found to be unable to respond to nitrate induction in the presence of ammonium in the same way as do wild-type strains. To explain these findings, we propose that the nitrate reductase molecule provides the recognition site for nitrate in the control system, such that when it is not complexed with nitrate it acts as a co-repressor, and, when it is complexed, as a co-inducer.
Heat-activated Endonuclease in
Bacillus subtilis
Authors: McCarthy Charlotte , Nester Eugene W.
Published: January 2020

A heat-stable, heat-activated endonuclease was found in sonic extracts of the transformable strain
Bacillus subtilis
168 when the organism was grown to logarithmic phase in minimal medium. The enzyme was not present in the poorly transformable strain 23. The endonuclease was stable to 100 C for 30 min and, in a crude extract, was activated by heating at 80, 90, or 100 C. The activation caused a 5- to 10-fold increase in total units of enzyme activity. Sucrose gradient centrifugation indicated that the enzyme in a crude preparation has a major form (molecular weight, 66,000) which remains unchanged after heat activation. Under the assay conditions employed, the endonuclease did not release acid-soluble material from the substrate, high molecular weight tritiated deoxyribonucleic acid. The product, in double-stranded form, had a molecular weight of approximately 10
5
, but it appeared to have undergone single-strand breaks.
B
12
Coenzyme-dependent Ribonucleotide Reductase in
Rhizobium
Species and the Effects of Cobalt Deficiency on the Activity of the Enzyme
Authors: Cowles Joe R. , Evans Harold J. , Russell Sterling A.
Published: January 2020

This investigation revealed that the ribonucleotide reductases in extracts of
Rhizobium leguminosarum, R. trifolii, R. phaseoli, R. japonicum
, and
R. meliloti
3DOal (ineffective in nitrogen fixation) are dependent upon B
12
coenzyme for activity.
Rhizobium
and certain
Lactobacillus
species are the only two groups of organisms known to contain B
12
coenzyme-dependent ribonucleotide reductases. Extracts of cobalt-deficient
R. meliloti
cells assayed in the presence of optimum B
12
coenzyme showed a 5- to 10-fold greater ribonucleotide reductase activity than comparable extracts from cells grown on a complete medium. Furthermore, cobalt-deficient cells were abnormally elongated and contained reduced contents of deoxyribonucleic acid. The addition of purified deoxyribonucleosides to cobalt-deficient cultures of
R. meliloti
failed to alleviate deficiency symptoms.
Ultrastructure of Blue-Green Algae
Authors: Gantt E. , Conti S. F.
Published: January 2020

Two freshwater blue-green algae,
Tolypothrix tenuis
and
Fremyella diplosiphon
, and an oscillatorialike marine alga, were found to possess structures on the photosynthetic lamellae which appear to correspond to the phycobilisomes of red algae. These homologous structures are important because they contain the phycobilins which are accessory pigments involved in photosynthesis. As in the red algae, the phycobilisomes were attached on the outer side of each lamellae, i.e., the side facing away from its own membrane pair. Although our study on
Anacystis nidulans
has not thus far revealed the presence of phycobilisomes, some observations were made on the structure of the polyhedral bodies. After negative staining, the polyhedral bodies were seen to be composed of regularly spaced subunits arranged in a crystalline array. Elongated segmented rods, which differed from the polyhedral bodies, were found in the nuclear region of apparently healthy
Tolypothrix
cells.
Separation of T-even Bacteriophage Deoxyribonucleic Acid from Host Deoxyribonucleic Acid by Hydroxyapatite Chromatography
Authors: Oishi M.
Published: January 2020

A simple and rapid method is described for separation of T-even bacteriophage deoxyribonucleic acid (DNA) from host (
Escherichia coli
) DNA by hydroxyapatite column chromatography with a shallow gradient of phosphate buffer at neutral
p
H. By this method, bacteriophage T2, T4, and T6 DNA (but not T5, T7, or λ DNA) could be separated from host
E. coli
DNA. It was found that glucosylation of the T-even phage DNA is an important factor in separation.
Fatty Acids in
Bacillus larvae, Bacillus lentimorbus
, and
Bacillus popilliae
Authors: Kaneda Toshi
Published: January 2020

The types of fatty acids produced by two strains each of
Bacillus larvae, B. lentimorbus
, and
B. popilliae
, and their distribution patterns, were studied by gas-liquid chromatography. All six organisms produced eight major fatty acids: six branched (iso-C
14
, -C
15
, -C
16
, and -C
17
, and anteiso-C
15
and -C
17
), two normal (n-C
14
and -C
16
), and two minor (n-C
15
and monounsaturated n-C
16
). In addition, some other trace acids were produced. Branched-chain fatty acids accounted for 54 to 85% of the total fatty acids. These compositions are similar to those previously found with 26 strains of 12 species of the genus
Bacillus
. Thus, an abundance of branched-chain fatty acids seems to be a characteristic of the biochemical nature of the genus
Bacillus
. It is noteworthy that marked differences between the nutritional requirements of the three insect pathogens used in the present study and those of the other 12 species of the genus
Bacillus
studied previously are not significantly reflected in their fatty acid composition.
Transformation of
Acinetobacter calco-aceticus
(
Bacterium anitratum
)
Authors: Juni Elliot , Janik Alice
Published: January 2020

A highly efficient transformation system has been demonstrated in a strain of
Acinetobacter calco-aceticus
(
Bacterium anitratrum
). During mixed growth of various stable, unencapsulated, mutant strains, deoxyribonucleic acid (DNA) is liberated and fully encapuslated transformants can be isolated. Purified DNA preparations have been used to transform suitable recipient mutant strains for ability to synthesize capsules, ability to dispense with a growth factor requirement, and resistance to streptomycin. When the wild-type strain is deprived of its capsule, either by mechanical stripping or by mutation, the unencapsulated cells tend to form large clumped masses. A nonclumping mutant of an unencapsulated strain has been isolated. When ability to synthesize capsules is transformed into this nonclumping strain, the resultant cells no longer form chains, unlike the wild-type encapsulated strain. It appears likely that the occurrence of transformation during growth of mixed cultures, with glucose or gluconate as the carbon source, may be the result of osmotic rupture resulting from the inability of unencapsulated strains to oxidize triose phosphates as fast as they are formed. The finding of transformation in
Acinetobacter
may provide an additional useful organism for the study of this mode of genetic transfer since this strain grows well in a simple mineral medium containing a single oxidizable source of carbon. Furthermore, no special supplementary factors seem to be required for transformation to take place.
Biochemical Studies of Bacterial Sporulation and Germination XV. Fatty Acids in Growth, Sporulation, and Germination of
Bacillus megaterium
Authors: Scandella Carl J. , Kornberg Arthur
Published: January 2020

The levels of fatty acids and their distribution were determined in cultures of
Bacillus megaterium
during growth, sporulation, and germination. Branched-chain pentadecanoates (br-C15) were the principal fatty acids of log-phase cells. Synthesis of branched-chain tetradecanoates (br-C14) during sporulation increased the relative proportion of these branched fatty acids in sporulating cells and in mature spores. The log-phase distribution was reestablished during outgrowth of the spore. The ratio of br-C15 to br-C14 could be radically altered by addition of their respective amino acid precursors, isoleucine and valine, without seriously affecting the sporulation process. The fatty acid composition of each of the purified phospholipids from log-phase cells was the same, indicating that each phospholipid receives a portion of the fatty acid pool present in the cell at the time of its synthesis. Similarly, the fatty acids of each of the spore phospholipids resembled those of the spore extract. Phospholipids accounted for two-thirds of the fatty acids of the log-phase but only one-third of those of the spore.
Requirement for Sodium in the Anaerobic Growth of
Aerobacter aerogenes
on Citrate
Authors: O'Brien R. W. , Stern Joseph R.
Published: January 2020

Anaerobic growth of
Aerobacter aerogenes
on citrate as a carbon source required the presence of Na
+
. The growth rate increased with increasing Na
+
concentration and was optimal at 0.10
m
Na
+
. The requirement was specific for Na
+
, which could not be replaced by K
+
, NH
4
+
, Li
+
, Rb
+
, or Cs
+
. K
+
was required for growth in the presence of Na
+
, the optimal K
+
concentration being 0.15 m
m
. Enzyme profiles were determined on cells grown in three different media: (i) intermediate Na
+
, high K
+
concentration, (ii) high Na
+
, high K
+
concentration, and (c) high Na
+
, low K
+
concentration. All cells contained the enzymes of the citrate fermentation pathway, namely, citritase and the Na
+
-requiring oxalacetate (OAA) decarboxylase. All of the enzymes of the citric acid cycle were present, except α-ketoglutarate dehydrogenase which could not be detected. The incomplete citric acid cycle was, in effect, converted into two biosynthetic pathways leading to glutamate and succinate, respectively. The specific activities of citritase and OAA decarboxylase were lowest in medium (i), and under these conditions the activity of OAA decarboxylase appeared to be limited in vivo by the availability of Na
+
. Failure of
A. aerogenes
to grow anaerobically on citrate in the absence of Na
+
can be explained at the enzymatic level by the Na
+
requirement of the OAA decarboxylase step of the citrate fermentation pathway and by the absence of an alternate pathway of citrate catabolism.
Effect of Formaldehyde on the Immunochemical and Biological Activity of Staphylococcal Endotoxin B
Authors: Silverman Sidney J. , Espeseth David A. , Schantz Edward J.
Published: January 2020

Staphylococcal enterotoxin B was treated with 0.15 or 0.3% formaldehyde at 37 C andpH 7.3. As early as 8 hr after addition of HCHO, the toxin was unable to precipitate as much antibody from antiserum as untreated toxin; greater amounts of treated toxin were required to reach equivalence and to inhibit precipitation. With increasing time, its reactivity decreased so that at 32 weeks it could precipitate only 20% as much antibody as untreated toxin. When other factors were kept constant, the degree of inactivation increased as the HCHO concentration increased from 0.6 to 1.4%. Treated toxin gave a “reaction of partial identity” by the Ouchterlony double-immunodiffusion technique. The emetic effect of the toxin for the monkey remained essentially unchanged for about 48 hr of treatment, but the amount required to cause death by the intravenous route increased from 25 to over 1,000 μg/kg of body weight. HCHO destroyed the pyrogenic effect for rabbits. The treated toxin remained immunogenic for rabbits even after 4 to 5 weeks of exposure to 0.3% HCHO at 37 C.
Immunity to Cholera: Relation of Fraction II of Type 2 Cholera Toxin to Vibriocidal Antibody
Authors: Kaur Jasbir , Burrows William
Published: January 2020

The nontoxic protein component in supernatant fluids of young cultures of the cholera vibrio in peptone dialysate broth contains an antigen identical in specificity to vibrio lipopolysaccharide. This material was heterogeneous after elution from diethylaminoethyl A50 Sephadex, and it contained at least five additional minor antigens. Identity was demonstrated by immunodiffusion methods, by the induction of specific vibriocidal antibody formation, and by specific interference in the vibriocidal reaction. The minor antigens appeared to be unrelated to the vibriocidal reaction. The major antigen was more highly immunogenic than lipopolysaccharide, giving higher and longer-persisting antibody titers in the rabbit, but lipopolysaccharide was the more effective interfering antigen per unit weight in the vibriocidal reaction. The nontoxicity and high immunogenic potency of the protein antigen suggest that it may be useful as an immunizing agent for the production of the antibacterial component of an effective immunity.
Hypoglycemic Activity of Endotoxin II. Mechanism of the Phenomenon in BCG-infected Mice
Authors: Shands J. W. , Miller V. , Martin H. , Senterfitt V.
Published: January 2020

The mechanism of the hypoglycemic activity of endotoxin in hyperreactive BCG mice was investigated. The mechanism was found to be an inhibition of the synthesis of glucose from noncarbohydrate sources. The possibilities of an induced hypermetabolic state and an induced release of insulin in response to endotoxin as causes for the hypoglycemic response were essentially ruled out. In addition, no clear-cut evidence of an insulin-like action by endotoxin was found in the in vivo setting.
Morphological, Cultural, Biochemical, and Serological Comparison of Japanese Strains ofVibrio parahemolyticuswith Related Cultures Isolated in the United States
Authors: Twedt Robert M. , Spaulding Procter L. , Hall Herbert E.
Published: January 2020

Morphological, cultural, biochemical, and serological characteristics of 79 strains ofVibrio parahemolyticusisolated from patients suffering from gastroenteric disease in Japan were compared with 17 suspectedV. parahemolyticuscultures isolated from wound infections and 14 nonpathogenic vibrios isolated from an estuarine environment in the United States. These groups were differentiated on the basis of several key reactions which included: the range of growth temperature and salt tolerance; the production of catalase and acetoin; the hydrolysis of starch; the fermentation and utilization as single carbon source of sucrose, cellobiose, and arabinose; and the ability to swarm on 1% agar. The separation of the groups on the basis of cultural and biochemical analyses was confirmed by means of slide agglutinations with specific anti-K antisera. The results of this study strongly suggest that the wound infection isolates areV. parahemolyticusspecies which are easily distinguished from the nonpathogenic estuarine vibrios.
Relation of the Segregative Origin of Chromosome Replication to the Origin of Replication After Amino Acid Starvation
Authors: Eberle Helen , Lark Karl G.
Published: January 2020

Cultures of
Escherichia coli
15T
−
and K-12 were labeled with
3
H-thymine before, during, and after amino acid starvation. The number of labeled segregating units was measured by autoradiography of microcolonies derived from the labeled cells. In both strains, labels inserted before starvation and during starvation appeared to segregate as if incorporated into the same polynucleotide strands. However, labels inserted during and after starvation segregated as if incorporated into different polynucleotide strands. In view of previous data, it was concluded that replication after amino acid starvation originates from the region of the chromosome which serves as the origin for replication during normal growth and division.
Induction and Properties of the Citrate Transport System in
Aerobacter aerogenes
Authors: Villarreal-Moguel E. I. , Ruiz-Herrera J.
Published: January 2020

The mediated transport of citrate in
Aerobacter aerogenes
was studied. According to data obtained by examining the distribution of radioactive citrate at room temperature and at 0 C, a carrier system appears to be located on the membrane. The carrier system is inducible and very specific, not acting on the related compounds isocitrate and cis-aconitate. Induction required synthesis of both ribonucleic acid and protein as determined by starving auxotrophic mutants and by using specific inhibitors of protein synthesis. Citrate transport was inhibited by
N
-ethyl maleimide, dinitrofluorobenzene, and uranyl nitrate. A kinetic study of uranyl nitrate inhibition revealed that the inhibition of citrate transport was different from that of glucose penetration. Cyanide also discriminated citrate from glucose penetration inhibiting only the former. These last results suggested that energy is required for citrate penetration.
Exopenicillinase Synthesis in
Staphylococcus aureus
Authors: Coles N. W. , Gross R.
Published: January 2020

In
Staphylococcus aureus
, penicillinase remaining cell-bound (60 to 75% of original total) after treatment with citrate does not become exopenicillinase. Exopenicillinase in these cells appears only under conditions permitting de novo penicillinase synthesis. By use of
14
C-labeled cells, it was shown that exopenicillinase consists of newly synthesized molecules which have not equilibrated with preformed membrane-bound enzyme.
Correlation Between the Surface Charge Density of Whole Cells and Electrophoretic Movement of Isolated Somatic Antigen of
Rhizobium trifolii
Authors: Humphrey Beverley A. , Vincent J. M.
Published: January 2020

Lipopolysaccharide somatic antigens isolated from two strains of
Rhizobium trifolii
showed the same electrophoretic mobility relative to each other as did the whole bacteria of these strains.
Sensitivity of Gliding Bacteria to Actinomycin D
Authors: Dworkin Martin
Published: January 2020

Growth of 20 of 22 strains of gliding bacteria (including fruiting myxobacteria) was inhibited by relatively low concentrations of actinomycin D.
α-Glycerophosphate Oxidase in
Streptococcus faecium
F 24
Authors: Koditschek L. K. , Umbreit W. W.
Published: January 2020

α-Glycerophosphate oxidase, in a strain of
Streptococcus faecium
, was found to be adaptive to aerated conditions of growth. The enzyme was purified and found to mediate electron transfer from α-glycerophosphate to O
2
, with the production of stoichiometric concentrations of H
2
O
2
and dihydroxyacetone phosphate. The enzyme is an anionic flavoprotein, with flavine adenine dinucleotide as the apparent prosthetic group. By manometric methods, a
K
m
of 6 × 10
−3
m
, with reference to substrate concentration, was obtained. An active reduced nicotinamide adenine dinucleotide diaphorase was closely associated with this enzyme in chromatographic mobility on ECTEOLA-cellulose. The purified α-glycerophosphate oxidase was not inhibited by KCN, azide, or sulfhydryl reagents, nor was it stimulated by α-lipoate, yeast extract, or other supplements.
Synthesis of Desthiobiotin from 7,8-Diaminopel-argonic Acid in Biotin Auxotrophs of
Escherichia coli
K-12
Authors: Eisenberg Max A. , Krell Kenneth
Published: January 2020

The synthesis of desthiobiotin from 7,8-diaminopelargonic acid (DAP) was demonstrated in resting cell suspensions of
Escherichia coli
K-12
bioA
mutants under conditions in which the biotin locus was derepressed. The biosynthetically formed desthiobiotin was identified by chromatography, electrophoresis, and by its ability to support the growth of yeast and those
E. coli
biotin auxotrophs that are blocked earlier in the biotin pathway. Optimal conditions for desthiobiotin synthesis were determined. Desthiobiotin synthetase activity was repressed 67% when partially derepressed resting cells were incubated in the presence of 3 ng of biotin per ml. Serine, bicarbonate, and glucose stimulated desthiobiotin synthesis apparently by acting as sources of CO
2
. The results of this study are consistent with an earlier postulated pathway for biotin biosynthesis in
E. coli
: pimelic acid → 7-oxo-8-aminopelargonic acid → DAP → desthiobiotin → biotin.
Cell-free Amino Acid-incorporating Systems from
Bacillus licheniformis
and
Bacillus stearothermophilus
10
Authors: Stenesh J. , Schechter N.
Published: January 2020

Cell-free amino acid-incorporating systems were prepared from log-phase cells of
Bacillus licheniformis
and
B. stearothermophilus
10. No differences were observed between the two systems with respect to the types and relative amounts of the ribosomes, the time dependence of incorporation, and the optimal magnesium ion concentration (4 m
m
). The
B. licheniformis
system showed greater dependence on added transfer ribonucleic acid (tRNA) and was less stimulated by polyuridylic acid (poly U) than the
B. stearothermophilus
10 system. Neither system was saturated at a level of 450 μg of poly U per incubation mixture. The S-100 fraction and the isolated tRNA inhibited incorporation in the
B. stearothermophilus
10 system at 55 C but not at 37 C. No such inhibition was observed in the
B. licheniformis
system at either temperature. The tRNA prepared from
B. subtilis, B. licheniformis
, or
B. stearothermophilus
10 could be used interchangeably in the two cell-free systems.
Synchronous Growth of
Escherichia coli
after Treatment with Fluorophenylalanine
Authors: Brostrom Margaret A. , Binkley Stephen B.
Published: January 2020

Treatment of exponentially growing
Escherichia coli
cells with the amino acid analogue,
p
-fluorophenylalanine (FPA), resulted in a decrease in the amount of deoxyribonucleic acid (DNA) present per cell. A minimum DNA content per cell was reached approximately 80 min after addition of FPA to the culture. After this time the DNA per cell rose to the level of the untreated cell. When an FPA-treated culture was resuspended in fresh medium containing no FPA 80 min after addition of the analogue, the increases in cell number and DNA became synchronous. Ribonucleic acid was synthesized immediately and continuously throughout the cell cycle, except during periods of DNA synthesis and cell division.
Mechanical Removal of F Pili, Type I Pili, and Flagella from Hfr and RTF Donor Cells and the Kinetics of Their Reappearance
Authors: Novotny Charles , Carnahan Judith , Brinton Charles C.
Published: January 2020

The effect of mechanical agitation (blending) on the removal of F pili, type I pili, and flagella from Hfr (high-frequency recombinant) and resistance transfer factor (RTF) fi
+
Escherichia coli
cells was studied by electron microscopy. The reduction in number and length of appendages was measured as a function of blendor speed under standard conditions of temperature, medium, cell density, and blendor configuration. F pili and flagella were removed within the same narrow range of blendor speeds. Type I pili were removed within a higher and broader range of speeds. The speed which reduced the average length of type I pili to 50% was 3.5 times the speed which reduced the average length of F pili to 50%. None of the speeds employed inhibited cell growth, viability, or the ability to produce cell appendages. The kinetics of reappearance of F pili and type I pili after removal by blending were also different. F pili grew out very rapidly, reaching 50% of their full length in 30 sec and their full length in 4 to 5 min. The number of attached F pili per cell also increased rapidly, reaching a constant value in 4 to 5 min. After 5 min, F pilus lengths were distributed around a modal value of about 1.2 μm, and the numbers of F pili per cell were distributed according to a Poisson distribution, with an average of 1.0 per cell. These reappearance kinetics, length distributions, and number distributions are consistent with a model of F-pilus outgrowth in which new F pili appear at random locations on the cell surface at an average rate of about once every 4 min, grow to their characteristic length in about 4 min, and then separate from the cell. F pili which had separated could absorb to the cells, leading to the presence of two classes of F pili on cells: those in the process of natural out-growth and those attached by absorption. Type I pili increased in length much more slowly than did F pili, although the fraction of cells having visible type I pili increased very rapidly after blending because of the large number of type I pili per cell. The fraction of flagellated cells increased even more slowly, reaching only 30% of the unblended fraction in 30 min. The application of blending spectra and reappearance kinetics to the identification of cell functions with surface structures is discussed.
Microbial Decomposition of Methionine and Identity of the Resulting Sulfur Products
Authors: Segal William , Starkey Robert L.
Published: January 2020

Various bacteria, actinomycetes, and filamentous fungi decomposed methionine, but only certain aerobic bacteria isolated from soil decomposed it in the absence of other organic substrates. These bacteria could grow on methionine as the only organic substrate and source of nitrogen and sulfur. Methionine was first deaminated and then demethiolated with production of methanethiol, part of which was oxidized to dimethyl disulfide. The amount of methanethiol that was oxidized varied with different cultures. A bacterial culture initially unable to grow on methionine developed capacity to do this in a medium which contained methionine and other growth substrates. The two sulfur products, methanethiol and dimethyl disulfide, are volatile and escaped from the media, resulting in a decrease in the sulfur content proportional to the amount of methionine decomposed.
Secondary and Tertiary Responses of the Induced Bactericidin from the West Indian Spiny Lobster,Panulirus argus
Authors: Evans E. Edward , Weinheimer Peter F. , Painter Barbara , Acton Ronald T. , Evans Marjorie L.
Published: January 2020

West Indian spiny lobsters,Panulirus argus, synthesized a hemolymph bactericidin after being injected with killed suspensions of gram-negative bacillus EMB-1 isolated from the normal gut of this lobster. To study differences between the primary response and secondary response, animals were given a primary antigen injection of EMB-1 followed by a second injection of the same antigen 22 to 51 days later. As a rule, secondary bactericidal responses were enhanced over the primary in a manner reminiscent of specific anamnesis in mammalian immunoglobulin synthesis. Immunological memory was also suggested when tertiary responses were compared to secondary and by the persistence of residual titers for many days or weeks without additional antigenic stimulation.
Killing and Lysis of Gram-negative Bacteria Through the Synergistic Effect of Hydrogen Peroxide, Ascorbic Acid, and Lysozyme
Authors: Miller T. E.
Published: January 2020

A mixture of hydrogen peroxide and ascorbic acid has been found to generate an antibacterial mechanism which is active against gram-negative bacteria. It results in bacterial death and renders the organism sensitive to lysis by lysozyme. Under the conditions used, horseradish peroxidase did not augment the antibacterial effect. It is suggested that the effector mechanism involves the generation of short-lived free radicals which disturb the integrity of the cell wall. This effect alone might kill bacteria by interfering with selective permeability, but in the presence of lysozyme a further bactericidal activity is accomplished by complete disruption of the cell. It is proposed that a transient antibacterial system such as that described could exist within phagocytic cells. Free radicals would be formed through the interaction of certain oxidizable substances and hydrogen peroxide, which is produced during the enhanced metabolic activity that accompanies ingestion of bacteria. Such a system would help to explain why macrophages, which are apparently devoid of preformed bactericidins, are nonetheless very efficient in killing most phagocytosed bacteria.
Purification and Reversible Inactivation of the Isocitrate Dehydrogenase from an Obligate Halophile
Authors: Hubbard Jerry S. , Miller Alan B.
Published: January 2020

The nicotinamide adenine dinucleotide phosphate-specific isocitrate dehydrogenase of
Halobacterium cutirubrum
is rapidly inactivated at low NaCl levels. As much as 75% of the initial activity can be restored by dialyzing the inactive enzyme against 4
m
NaCl. A mixture of 4 m
m
isocitrate and 10 m
m
MnCl
2
gives the same protection as 4
m
NaCl but does not replace the NaCl requirement for reactivation. The reactivated and native enzymes have identical sedimentation rates on sucrose gradients, electrophoretic mobilities on polyacrylamide gels, and elution rates from Sephadex G-200. However, there are distinct differences between the active and inactive forms of the enzyme. Compared with the active enzyme, the inactive protein has a lower sedimentation rate, a lower electrophoretic mobility, and a faster elution rate from Sephadex. These differences indicate that inactivation causes a major conformational change in the protein. Presumably, the removal of NaCl permits the enzyme to expand into a less dense, inactive form. The isocitrate dehydrogenase was purified 69-fold by a procedure involving the following steps. When the enzyme is selectively protected with isocitrate and MnCl
2
at low ionic strength, most of the contaminating proteins are precipitated with (NH
4
)
2
SO
4
at 0.9 saturation. The enzyme in the supernatant fluid is then inactivated at low NaCl levels, precipitated with 0.5 saturated (NH
4
)
2
SO
4
, and reactivated with 4
m
NaCl. Minor impurities are removed by gel filtration on Sephadex G-200. The resulting preparation is more than 95% pure as judged by disc electrophoresis.
Chemical Studies on the Structure of Mucopeptide Isolated from
Streptococcus bovis
Authors: Kane Judith , Lackland Henry , Karakawa W. W. , Krause R. M.
Published: January 2020

Mucopeptides isolated from
Streptococcus bovis
cell walls were found to be composed of alanine, glutamic acid, lysine, and threonine in a mole ratio of 3:1:1:1. A dipeptide,
N
ε
-lysylthreonine, was isolated from
S. bovis
mucopeptide by ion-exchange chromatography. This finding suggests that threonine is associated with the bridge which cross-links adjacent tetrapeptides by connecting the ε-amino group of lysine of one tetrapeptide to the carboxyl group of
d
-alanine of another to form the mucopeptide matrix.
Pectin-fermenting Bacteria Isolated from the Bovine Rumen
Authors: Dehority B. A.
Published: January 2020

Thirty-two strains of pectin-fermenting rumen bacteria were isolated from bovine rumen contents in a rumen fluid medium which contained pectin as the only added energy source. Based on differences in morphology and the Gram stain, 10 of these strains were selected for characterization. Two strains were identified as
Lachnospira multiparus
, four strains were identified as
Butyrivbrio fibrisolvens
, and three strains were identified as
Bacteroides ruminicola
. Characteristics of the remaining strain did not correspond with any previously described species. It was a gram-positive anaerobic coccus, 1.0 to 1.2 μm in diameter, and occurred primarily as single cells or diplococci. The strain fermented pectin rapidly but showed little or no growth on any other energy sources tested. The only detectable end products were acetic acid and gas, a portion of which was identified as hydrogen. Although the physiological characteristics of this organism differ markedly from other described species, it has been placed in the genus
Peptostreptococcus
on the basis of morphology, Gram stain, relations to oxygen, and the occurrence of cell division in only one plane. End products of fermentation are somewhat similar to those of the cellulolytic ruminococci. Eight previously characterized strains of cellulolytic bacteria isolated in nonselective media were unable to ferment pectin, whereas ten strains of hemicellulolytic rumen bacteria, eight of which were isolated with a xylan medium, showed considerable variation in this characteristic.
Formation of Thiosulfate from Sulfite byDesulfovibrio vulgaris
Authors: Suh Byungse , Akagi J. M.
Published: January 2020

Crude extracts ofDesulfovibrio vulgarisreduced sulfite to sulfide. Ammonium sulfate fractionation of crude extracts separated a thiosulfate-forming system from sulfite- and thiosulfate-reductase activities. Further purification by sucrose density centrifugation separated the thiosulfate-forming system into two components, both of which were required for the reaction. In addition to these two components, cytochromec3, ferredoxin, and hydrogenase were required to form thiosulfate from sulfite. By absorption spectra and from the effect ofpH and substrate concentration, the ionic species acting as the substrate for thiosulfate-formation was concluded to be bisulfite.
Escherichia coli
K-12 Mutants Resistant to Nalidixic Acid: Genetic Mapping and Dominance Studies
Authors: Hane Michael W. , Wood Thomas H.
Published: January 2020

Escherichia coli
K-12 strains tested so far (approximately 20) can be separated into three groups on the basis of their abilities to form colonies on nutrient agar supplemented with nalidixic acid (NAL): (i) Nal
s
or wild type (no growth at 1 to 2 μg/ml); (ii) NalA
r
(growth at 40 μg/ml or higher); and (iii) NalB
r
(growth at 4 μg/ml, but no growth at 10 μg/ml). The NalA
r
group has a spectrum of sensitivity ranging from 60 to over 100 μg/ml. All Hfr strains of the NalA
r
and NalB
r
groups transfer NAL resistance to recipient cells at genetic loci which are at 42.5 ± 0.5 and 51 ± 1 min, respectively, on the Taylor-Trotter map. Some members of the NalA
r
group also have the genetic locus for NalB
r
. The
nalA
s
allele is completely dominant to
nalA
r
in a partial diploid configuration. In haploids,
nalA
r
-
nalB
r
is phenotypically NalA
r
;
nalA
r
-
nalB
s
is NalA
r
; and
nalA
s
-
nalB
r
is NalB
r
. The map location of
nalA
and the easy differentiation between NalA
r
and NalA
s
allow this marker to be used as a counterselector in bacterial conjugation experiments.
Characterization of the Deoxyribonucleic Acid of Various Strains of Halophilic Bacteria
Authors: Moore Richard L. , McCarthy Brian J.
Published: January 2020

Bacteria classified as extreme halophiles, in the genera
Halobacterium
and
Halococcus
, contain deoxyribonucleic acid (DNA) which displays two components in a CsCl equilibrium density gradient. The base composition of the major DNA component ranges from 66 to 68% guanine plus cytosine (GC), whereas that of the satellite DNA comprising some 11 to 36% of the total, is between 57 and 60% GC. Purification of the bacterial cells in a CsCl density gradient and other more conventional strain purification procedures both indicated that the presence of the satellite DNA component is not a result of mixed cultures.
Sequential Entry of Transforming Markers into
Neisseria meningitidis
After Chromosome Alignment
Authors: Jyssum Kaare
Published: January 2020

The kinetics of appearance of transformants as a function of time of exposure to deoxyribonucleic acid (DNA) was examined in
Neisseria meningitidis
. Incubation with chloramphenicol for as long as 2 hr, which probably leads to chromosome alignment, resulted in augmentation of the lag period before the appearance of the first transformants. The lag periods thus found were dependent upon the marker tested. This permitted the construction of a time map according to the lag periods observed for individual markers. This map was in general agreement with the chromosome map of the recipient strain as determined by marker frequency analysis. Transformation of recipient cells with chromosomes aligned by growth to the stationary phase showed the same type of increased lag in the appearance of transformants before the logarithmic phase of growth had again been reached. These results support the assumption that the nature of the marker accepted by a recipient cell corresponds to the marker present at the replication point of the chromosome. In the absence of DNA and protein synthesis, the uptake of one marker seems to be successively followed by other markers in a linear order determined by the chromosome of the recipient cell.