bluuebunny/crossref_metadata_2025 huggingface dataset:
ULTRASTRUCTURE OFVEILLONELLAAND MORPHOLOGICAL CORRELATION OF AN OUTER MEMBRANE WITH PARTICLES ASSOCIATED WITH ENDOTOXIC ACTIVITY
Authors: Bladen Howard A. , Mergenhagen Stephan E.
Published: January 2020

Bladen, HowardA. (National Institute of Dental Research, Bethesda, Md.),and Stephan E. Mergenhagen. Ultrastructure ofVeillonellaand morphological correlation of an outer membrane with particles associated with endotoxic activity. J. Bacteriol.88:1482–1492. 1964.—Normal, phenol-water extracted, and lysozyme-treatedVeillonellacells were embedded in Vestopal W, sectioned, and examined by electron microscopy. Normal cells as well as the phenol-water extract (endotoxin) were examined by negative and positive contrast techniques. In thin sections of normal cells, three separate structural entities were observed surrounding the protoplasm, and were referred to as the outer membrane, the solid membrane, and the plasma membrane. The outer membrane was a membrane composed of two dense layers (30 A) separated by a less-dense layer (20 A), and followed a convoluted and continuous path around the cell. The solid membrane appeared as a taut, dense structure 100 to 500 A wide, and was separated from the outer membrane by up to several hundred Ångstroms. The plasma membrane was a unit-type membrane. After cells were treated with phenol-water, the outer membrane was absent, but the cells remained intact owing to the solid membrane. Observation of the phenol-water extract (endotoxin) revealed predominantly circular particles or discs which had approximately the same dimensions in height as the outer membrane had in width. Negatively stained whole cells showed similar structures on their surface. Lysozyme treatment of the cells did not affect the outer membrane; however, the solid membrane became diffuse and often disappeared, suggesting that the outer membrane and the solid membrane were separate structures.
EVIDENCE FOR A TRICARBOXYLIC ACID CYCLE IN
MYCOPLASMA HOMINIS
Authors: VanDemark P. J. , Smith P. F.
Published: January 2020

VanDemark
, P. J. (Cornell University, Ithaca, N.Y.),
and P. F. Smith
. Evidence for a tricarboxylic acid cycle in
Mycoplasma hominis
. J. Bacteriol.
88:
1602–1607. 1964.—Resting cells of acetate-grown
Mycoplasma hominis
strain 07 oxidized the various intermediates of the tricarboxylic and glyoxylate cycles, with the exception of sodium citrate and glyoxylate. Extracts of these cells possessed isocitric dehydrogenase, isocitratase, α-ketoglutaric dehydrogenase, succinic dehydrogenase, fumarase, malic dehydrogenase, citratase, and acetyl coenzyme A kinase activities. With the assay conditions employed, condensing enzyme, malate synthetase, and phosphotransacetylase activities were negligible. Incubation of sodium acetate-
2-C
14
with the various intermediates of the tricarboxylic acid cycle in the presence of cell-free extracts resulted in exchange of the isotope with these compounds as well as the formation of other labeled intermediates of the tricarboxylic acid cycle. Oxidation of sodium acetate-
2-C
14
alone resulted in the formation of labeled succinate, fumarate, and malate.
BIOSYNTHESIS OF YEAST CAROTENOIDS
Authors: Simpson Kenneth L. , Nakayama T. O. M. , Chichester C. O.
Published: January 2020

Simpson, KennethL. (University of California, Davis), T. O. M.Nakayama, and C. O. Chichester. Biosynthesis of yeast carotenoids. J. Bacteriol.88:1688–1694. 1964.—The biosynthesis of carotenoids was followed inRhodotorula glutinisand in a new strain, 62-506. The treatment of the growing cultures by methylheptenone, or ionone, vapors permitted observations of the intermediates in the biosynthetic pathway. On the basis of concentration changes and accumulation in blocked pathways, the sequence of carotenoid formation is postulated as phytoene, phytofluene, ζ-carotene, neurosporene, β-zeacarotene, γ-carotene, torulin, a C40aldehyde, and torularhodin. Torulin and torularhodin were established as the main carotenoids of 62-506.
DIFFERENTIATION OF EXOTOXIN AND OTHER BIOLOGICALLY ACTIVE SUBSTANCES IN
PSEUDOMONAS PSEUDOMALLEI
FILTRATES
Authors: Heckly Robert J.
Published: January 2020

Heckly, Robert
J. (University of California, Berkeley). Differentiation of exotoxin and other biologically active substances in
Pseudomonas pseudomallei
filtrates. J. Bacteriol.
88:
1730–1736. 1964.—Denaturing agents such as phenol, formaldehyde, and urea reduced lethal toxicity and proteolytic activity of partially purified preparations from
Pseudomonas pseudomallei
at about the same rate. Neither toxin nor enzyme was stable at pH 11, when the solution was adjusted with sodium hydroxide, but there was a slight difference in their rates of inactivation. However, under certain conditions, ammonium hydroxide destroyed most of the enzymatic activity with only a slight effect on lethality. Conversely, toxin was less stable in acid solutions than was the enzyme. Thus, treatment with ammonium hydroxide or acetic acid yielded preparations with either a low or a high enzyme-to-toxin ratio, indicating that lethality was not dependent on enzyme activity. Although proteolysis of any one of the essential factors in the blood coagulation system can inhibit clotting of blood, the potent anticoagulant activity of culture filtrates was not associated with its proteolytic activity, but was directly correlated with lethal toxicity. It is of considerable interest that the necrotoxicity was, however, associated with enzymatic activity and not with lethality. Serological reactivity of the enzyme, as well as its proteolytic activity, was altered by ammonium hydroxide. Similarly, antigenicity and toxicity of the lethal toxin were reduced by acidification. Each acid- or alkali-treated preparation produced a single precipitin line in double diffusion in agar when reacted with antisera produced by injection of crude filtrate. Partially purified preparations, having both lethal and enzymatic activity, produced two lines, one identifiable with the enzyme preparation, and one with the toxin. Furthermore, specific precipitation with the respective antisera removed either enzyme or toxin from crude preparations. Therefore, the lethal exotoxin and proteolytic enzyme are separable entities.
ULTRASTRUCTURE OF THE EXOSPORIUM ENVELOPING SPORES OFBACILLUS CEREUS
Authors: Gerhardt Philipp , Ribi Edgar
Published: January 2020

Gerhardt, Philipp(The University of Michigan, Ann Arbor),and Edgar Ribi. Ultrastructure of the exosporium enveloping spores ofBacillus cereus. J. Bacteriol.88:1774–1789. 1964.—Structural details in the outer envelope of spores, such as those ofBacillus cereusandB. anthracis, were studied by electron microscopy and by X-ray diffraction analysis. Procedures were developed for isolating homogeneous fragments of the membrane with minimal damage to or germination of the spore proper. Exosporium ofB. cereusappeared to embody two main layers. An outer layer was made up of a nap of hairlike projections, irregularly distributed and about 250 A deep; these arose from an intermediate covering, about 60 A in depth and similarly lead-stainable. An inner basal layer had a hexagonally perforate surface pattern of holes, averaging 76 A from center to center, and was made up of four lamellae, which could fragment into crystal-like elements. The intact basal membrane was about 190 A thick and the thinnest elements, 45 A. Microscopic observations of a crystal-like nature of the exosporium basal membrane were confirmed by X-ray diffraction analysis; the pattern of reflection lines in powder diagrams of exosporium fragments or paracrystals, or intact spores, corresponded to a hexagonal, close-packed crystal structure. The unit cell was calculated to have dimensions of 7.6 A along theaaxis and 11.9 A along thecaxis of the space lattice.
Multiple Cellulase System from
Streptomyces antibioticus
Authors: Enger M. D. , Sleeper B. P.
Published: January 2020

Enger
, M. D. (North Dakota State University, Fargo),
and B. P. Sleeper
. Multiple cellulase system from
Streptomyces antibioticus
. J. Bacteriol.
89:
23–27. 1965.—Starch-block zone electrophoresis was used to isolate five electrophoretically distinct, active cellulolytic components (I to V) from the crude extracellular cellulase system of
Streptomyces antibioticus
(strain C2A). Agar diffusion precipitin analyses demonstrated the immunological identity of components I, II, and III, and the nonidentity of IV and V with each other and with I to III. Kinetic studies of the purified enzymes showed a sharp decrease in the viscosity of the substrate, carboxymethylcellulose, with only a small increase in reducing sugars. These results indicated that all five enzymes are endocellulases.
Formation and Interrelationships of Tryptophanase and Tryptophan Synthetases in
Escherichia coli
Authors: Newton W. Austin , Snell Esmond E.
Published: January 2020

Newton, W. Austin
(University of California, Berkeley),
and Esmond E. Snell
. Formation and interrelationships of tryptophanase and tryptophan synthetases in
Escherichia coli
. J. Bacteriol.
89:
355–364. 1965.—In addition to the classical tryptophan-repressible tryptophan synthetase (TSase-
tr
), tryptophan auxotrophs of
Escherichia coli
contain another distinct tryptophan synthetase (TSase-
ti
) which is induced by tryptophan and is identical with tryptophanase (TPase).
Escherichia coli
B (wild type) forms only TSase-
tr
when the growth medium lacks tryptophan. When tryptophan is supplied, parallel induction of TPase and TSase-
ti
occurs while TSase-
tr
is repressed. Antiserum prepared against purified TPase neutralized TPase and TSase-
ti
equally, but not TSase-
tr
. TPase-negative strains of
E. coli
do not form TSase-
ti
. Unlike TSase-
tr
, TSase-
ti
is not readily detected by whole-cell assays. In the tryptophan auxotroph,
E. coli
B/1t7, a direct correlation exists between the effectiveness of 4-, 5-, and 6-methyl-tryptophan in inducing TPase and in promoting growth in the presence of indole. In a mutant of this organism,
E. coli
B/1t7-A, which is constitutive for TPase, 5-methyl-tryptophan and other substrates of TPase increased the rate of growth on limiting indole, a result ascribed to their ability to inhibit degradation of tryptophan and to supply the 3-carbon side chain for synthesis of tryptophan by TPase. This organism produced maximal amounts of TPase when inocula from log-phase cells grown in tryptophan-supplemented minimal medium were allowed to undergo two cell generations in an enriched broth medium.
Mycobacterium leprae
in Mice: Minimal Infectious Dose, Relationship Between Staining Quality and Infectivity, and Effect of Cortisone
Authors: Shepard Charles C. , McRae Dorothy H.
Published: January 2020

Shepard, Charles
C. (Communicable Disease Center, U.S. Public Health Service, Atlanta, Ga.),
and Dorothy H. McRae
.
Mycobacterium leprae
in mice: minimal infectious dose, relationship between staining quality and infectivity, and effect of cortisone. J. Bacteriol.
89:
365–372. 1965.—The minimal infectious dose of
Mycobacterium leprae
in mouse foot pads was found to be on the order of 10 solidly staining bacilli. In a titration experiment, the actual number found was 3.4 to 34 solid bacilli, and the order of magnitude was confirmed by experience with inocula containing varying numbers of solidly staining leprosy bacilli from mouse passage and from clinical sources. The acid-fast staining quality of leprosy bacilli was related in a useful way to the subsequent rate at which bacillary growth appeared. When the proportion of solidly staining bacilli was high, the calculated generation time was shortest, and the lower the proportion, the longer the generation times. The results were in accord with the hypothesis that all viable bacilli are solid, and that when they die, most of them become nonsolid. Varying proportions of the dead bacilli, perhaps up to 10%, remain solid, at least temporarily. The growth curve of
M. leprae
in mice was followed in several experiments with total counts of acid-fast bacteria and determination of the ratio of solid bacilli. What had been called a maximal stationary phase was seen to consist of sequential phases of conversion of solid to nonsolid bacilli (death), reappearance of solid bacilli (growth), and conversion of solid to nonsolid bacilli (death). When cortisone was administered, leprosy bacilli grew somewhat more slowly during the logarithmic phase, but attained a higher level, especially of solidly staining bacilli.
Protoplast Lysis and Inhibition of Growth of
Bacillus licheniformis
by Bacitracin
Authors: Snoke John E. , Cornell Neal
Published: January 2020

Snoke, John
E. (University of California, Los Angeles),
and Neal Cornell
. Protoplast lysis and inhibition of growth of
Bacillus licheniformis
by bacitracin. J. Bacteriol.
89:
415–240. 1965.—The growth of
Bacillus licheniformis
is inhibited by bacitracin, the antibiotic which the organism itself produces. The effect of the antibiotic is confined to the early growth phase of the organism. Bacitracin will produce a rapid lysis of protoplasts of
B. licheniformis
and
Micrococcus lysodeikticus
. The lytic process requires cadmium or zinc ions, and the rate and extent of lysis depends upon the amount of bacitracin and metal ion added. Although
B. licheniformis
and
M. lysodeikticus
differ markedly in their sensitivity to bacitracin, the protoplasts from these two organisms are equally susceptible to lysis by the antibiotic.
Effect of Biotin on Fatty Acid Distribution in
Escherichia coli
Authors: Gavin John J. , Umbreit Wayne W.
Published: January 2020

Gavin, John
J. (Rutgers, The State University, New Brunswick, N.J.),
and Wayne W. Umbreit
. Effect of biotin on fatty acid distribution in
Escherichia coli
. J. Bacteriol.
89:
437–443. 1965.—Biotin deficiency causes changes in the composition and distribution of the fatty acids in cell wall-cell membrane fractions of
Escherichia coli
T 94A. Most notable among the fatty acid changes are decreased amounts of unsaturated fatty acids, the presence of unsaponifiable lipid material, and the lack of a lipopolysaccharide fraction in the cell wall-cell membrane. Also, though the hexane-extractable material from the lipoprotein fraction of biotin-adequate cells will transfer glucose from water to hexane, the same material from biotin-deficient cells will not.
Effect of Ethionine on the Ribonucleic Acid, Deoxyribonucleic Acid, and Protein Content of
Escherichia coli
Authors: Smith Robert C. , Salmon W. D.
Published: January 2020

Smith, Robert
C. (Auburn University, Auburn, Ala.),
and W. D. Salmon
. Effect of ethionine on the ribonucleic acid, deoxyribonucleic acid, and protein content of
Escherichia coli
. J. Bacteriol.
89:
687–692. 1965.—The addition of ethionine to cultures of
Escherichia coli
K-12 W6, a methionine-requiring auxotroph, led to inhibition of the rate of increase in optical density when the ratio of ethionine to methionine was 200:1. When the ratio was 600:1, the increase in optical density became linear. When ethionine was substituted for methionine in the medium, the optical density of the culture increased, and there was a parallel increase in protein content. There was no cell division in these cultures. The rate of synthesis of ribonucleic acid (RNA) in a culture containing ethionine was similar to that of a culture deprived of methionine, but the synthesis of deoxyribonucleic acid in a culture with ethionine was about twice that of a culture deprived of methionine. No detectable radioactivity from ethionine-ethyl-
1-C
14
was incorporated into RNA. Ethionine-ethyl-1-
C
14
was readily incorporated into the protein fraction.
Preparation of Fluorescein Isothiocyanate-Labeled γ-Globulin by Dialysis, Gel Filtration, and Ion-Exchange Chromatography in Combination
Authors: Dedmon Robert E. , Holmes Albert W. , Deinhardt Friedrich
Published: January 2020

Dedmon, RobertE. (Presbyterian-St. Luke's Hospital, Chicago, Ill.),Albert W. Holmes, and Friedrich Deinhardt. Preparation of fluorescein isothiocyanate-labeled γ-globulin by dialysis, gel filtration, and ion-exchange chromatography in combination. J. Bacteriol.89:734–739. 1965.—Antiviral immune γ-globulins isolated from rabbit and guinea pig sera were labeled through dialysis membranes with fluorescein isothiocyanate and purified in several ways to eliminate nonspecific staining. Gel filtration of the conjugate with Sephadex G-25 coarse beads followed by column fractionation with diethylaminoethyl-Sephadex yielded consistently highly specific staining materials. Fluorescein-protein ratios varied between 1.0 and 4.0. This technique has proved to be simple and reliable, and is less time-consuming than previous techniques.
Resistance of Coagulase-Positive Staphylococci to Methicillin and Oxacillin
Authors: Gravenkemper Charles F. , Brodie Jean L. , Kirby William M. M.
Published: January 2020

Gravenkemper, Charles
F. (University of Washington School of Medicine, Seattle),
Jean L. Brodie, and William M. M. Kirby
. Resistance of coagulase-positive staphylococci to methicillin and oxacillin. J. Bacteriol.
89:
1005–1010. 1965.—Two strains resistant to methicillin were discovered among 541 strains of
Staphylococcus aureus
isolated in a clinical laboratory during a 1-yr period, and their properties were compared with those of strains isolated in Europe. The two strains were very active producers of penicillinase, and exhibited cross-resistance with other antistaphylococcal antibiotics. Like the European strains, our resistant cultures showed resistance to methicillin only with large inocula, and consisted of a mixture of cells. The great majority were sensitive and underwent early swelling and lysis, and only a small minority of the bacteria were able to grow in the presence of methicillin. The methicillin-resistant strains caused destruction of methicillin and oxacillin in vitro, but the rate of hydrolysis was slow. Antibiotic destruction was probably due to high concentrations of staphylococcal penicillinase, and not to another specific enzyme. These observations are helpful in explaining why resistance of staphylococci to the synthetic penicillins has not become a significant clinical problem.
Nickel-Dependent Chemolithotrophic Growth of Two
Hydrogenomonas
Strains
Authors: Bartha R. , Ordal E. J.
Published: January 2020

Bartha
, R. (University of Washington, Seattle),
and E. J. Ordal
. Nickel-dependent chemolithotrophic growth of two
Hydrogenomonas
strains. J. Bacteriol.
89:
1015–1019. 1965.—The trace element requirements for growth of facultative chemolithotrophic
Hydrogenomonas
strains H1 and H16 were investigated under both autotrophic and heterotrophic conditions. The organisms were grown in a mineral medium, rendered deficient in trace elements by extraction with 8-hydroxyquinoline and chloroform, and, in some cases, by coprecipitation with copper. The organic substrates, succinate and fumarate, used for heterotrophic growth were treated in a similar fashion. Acetate and butyrate were purified by redistillation. It was found that iron alone was required for heterotrophic growth (optimal concentration, 1.5 × 10
−6
m
Fe
+++
), but cells grown chemolithotrophically on molecular hydrogen required the addition of nickel. The yield of protein was proportional to the nickel added, reaching a maximum at 3 × 10
−7
m
Ni
++
. Manganese, cobalt, copper, and zinc, alone or in combination, failed to substitute for nickel in the experiments with
Hydrogenomonas
. Although nickel is required specifically for the chemolithotrophic growth of
Hydrogenomonas
, nickel deficiency did not affect: (i) the synthesis or activation of hydrogenase, (ii) the Knallgas reaction, (iii) the assimilation of CO
2
by resting cells, or the synthesis of the storage material poly-β-hydroxybutyric acid. It is suggested that nickel participates in some reaction involved in CO
2
fixation by growing cells.
Environmental Control of Cell Composition in
Escherichia coli
Authors: Wright D. N. , Lockhart W. R.
Published: January 2020

Wright
, D. N. (Iowa State University, Ames),
and W. R. Lockhart
. Environmental control of cell composition in
Escherichia coli
. J. Bacteriol.
89:
1026–1031. 1965.—
Escherichia coli
was grown in continuous culture at various rates in a defined medium with either the carbon or the nitrogen source as rate-limiting substrate. Average cell size and the cellular content of ribonucleic acid, protein, and free amino acids varied both with growth rate and with the identity of the limiting nutrient, being greatest at high growth rates, and greater for nitrogen-limited than for carbon-limited populations. Immunoelectrophoresis of cell extracts revealed antigenic components associated uniquely with growth rate, and others associated with the identity of the limiting nutrient on which cells had been grown. Cell composition thus appears to reflect the physiological adjustment of a microbial population to its total environment.
Egg Yolk Factor of
Staphylococcus aureus
II. Characterization of the Lipase Activity
Authors: Shah D. B. , Wilson J. B.
Published: January 2020

Shah
, D. B. (University of Wisconsin, Madison),
and J. B. Wilson
. Egg yolk factor of
Staphylococcus aureus
. II. Characterization of the lipase activity. J. Bacteriol.
89:
949–953. 1965.—The staphylococcal egg yolk factor was characterized as a lipase. The enzyme had an optimal
p
H of 7.8, but the optimal
p
H of stability was 7. Substrate specificity data showed that the relative rate of hydrolysis was lowest with triacetin as substrate, was maximal with tributyrin, and decreased as the chain length of the acyl moieties increased. The enzyme showed an absolute requirement for a fatty acid acceptor like calcium, when the acyl moiety of triglyceride was water-insoluble. Magnesium, strontium, and barium functioned equally well as fatty acid acceptors. The enzyme was able to hydrolyze coconut oil, peanut oil, olive oil, and egg yolk oil.
Drug Resistance of Staphylococci II. Joint Elimination and Joint Transduction of the Determinants of Penicillinase Production and Resistance to Macrolide Antibiotics
Authors: Mitsuhashi Susumu , Hashimoto Hajime , Kono Megumi , Morimura Masato
Published: January 2020

Mitsuhashi, Susumu
(Gunma University, Maebashi, Japan),
Hajime Hashimoto, Megumi Kono, and Masato Morimura
. Drug resistance of staphylococci. II. Joint elimination and joint transduction of the determinants of penicillinase production and resistance to macrolide antibiotics. J. Bacteriol.
89:
988–992. 1965.—Strains of
Staphylococcus aureus
, which show high resistance to macrolide antibiotics (erythromycin, oleandomycin, leucomycin, and spiramycin) and the capacity to produce penicillinase, have been isolated from clinical sources. The determinants of penicillinase production (PCase
+
) and resistance to macrolide antibiotics (MAC
r
) of these strains were irreversibly eliminated by treatment with acridine or with ultraviolet light. Among the 18 strains tested, PCase
+
and MAC
r
were eliminated from all strains except one, which lost only PCase
+
but not MAC
r
. The characters PCase
+
and MAC
r
were jointly transduced with the aid of phage lysates, obtained from the resistant donors by ultraviolet irradiation, into staphylococcal strains sensitive to PC and MAC. Segregation of PCase
+
and MAC
r
was rarely observed after transduction. From these results, it is suggested that the determinants of both PCase
+
and MAC
r
of staphylococci are located close together on a single genetic element, i.e., a plasmid (or episome), which exists extrachromosomally.
Mechanism of Tryptic Activation ofClostridium botulinumType E Toxin
Authors: Gerwing Julia , Dolman Claude E. , Ko Arthur
Published: January 2020

Gerwing, Julia(University of British Columbia, Vancouver, B.C., Canada),Claude E. Dolman, and Arthur Ko. Mechanism of tryptic activation ofClostridium botulinumtype E toxin. J. Bacteriol.89:1176–1179. 1965.—The toxic peptide of trypsin activatedClostridium botulinumtype E toxin was purified by chromatography through columns packed with Sephadex G-75 and G-50. The molecular weight of the active peptide was estimated to lie between 10,000 and 12,000. Amino acid analyses indicated that the active peptide had lost at least 18 of the amino acid residues present in the original protein. The active peptide and the original protein were found to have different N-terminal amino acid residues. The mechanism of tryptic activation apparently involves chiefly the removal of amino acids from the N-terminus of the toxin molecule.
Major Products of Glucose Dissimilation by
Pseudomonas natriegens
Authors: Eagon R. G. , Cho H. W.
Published: January 2020

Eagon
, R. G. (University of Georgia, Athens),
and H. W. Cho
. Major products of glucose dissimilation by
Pseudomonas natriegens
. J. Bacteriol.
89:
1209–1211. 1965.—
Pseudomonas natriegens
aerobically catabolized glucose to yield predominantly acetic acid, pyruvic acid, and CO
2
, whereas little or no lactic acid was formed. Under anaerobic conditions, glucose in an enriched medium was fermented to yield acetic acid and lactic acid but no pyruvic acid or CO
2
. Glucose in a basal salts medium was fermented to yield predominantly acetic acid, lactic acid, and CO
2
, while small amounts of pyruvic acid were detected. It was suggested that the aerobic accumulation of acidic products results from rapid glucose dissimilation to the oxidation level of pyruvic acid, followed by a less rapidly functioning tricarboxylic acid cycle.
Residual Activity of Thermally Denatured Transforming Deoxyribonucleic Acid from
Haemophilus influenzae
Authors: Barnhart Benjamin J.
Published: January 2020

Barnhart, Benjamin
J. (Johns Hopkins University School of Hygiene and Public Health, Baltimore, Md.). Residual activity of thermally denatured transforming deoxyribonucleic acid from
Haemophilus influenzae
. J. Bacteriol.
89:
1271–1279. 1965.—The level of residual transforming activity of heated deoxyribonucleic acid (DNA) (i.e., 1 to a few per cent of native DNA-transforming activity) was found to be independent of the heating and quenching temperatures and less susceptible than native or renatured DNA to heat inactivation upon prolonged heating above or below the critical melting temperature. Similar dose-response curves were obtained for inactivation by formamide of native and renatured DNA, but the residual-active material was much more resistant. Heating DNA above the
T
m
in the presence of 1% formaldehyde resulted in a level of residual activity 4 logs lower than that obtained without formaldehyde. Residual-active material was not inactivated by
Escherichia coli
phosphodiesterase, but it was susceptible to snake venom phosphodiesterase. A new genetic marker was induced in heated-quenched DNA but not in purified residual-active material following nitrous acid treatment. Residual activity was found to be less susceptible to ultraviolet inactivation and to band at a higher density region in CsCl than native DNA. In conclusion, it is suggested that the residual-active material is a structure formed by intrastrand hydrogen bonding of the separated units of heated-quenched DNA. Such a configuration would result in at least a partially double-stranded structure, which is probably the essential characteristic of the residual-active material endowing it with biological activity.
Immunogenic Activity of a Ribosomal Fraction Obtained from
Mycobacterium tuberculosis
Authors: Youmans Anne S. , Youmans Guy P.
Published: January 2020

Youmans, Anne
S. (Northwestern University Medical School, Chicago, Ill.),
and Guy P. Youmans
. Immunogenic activity of a ribosomal fraction obtained from
Mycobacterium tuberculosis
. J. Bacteriol.
89:
1291–1298. 1965.—The highly immunogenic particulate fraction obtained from mechanically ruptured cells of the H37Ra strain of
Mycobacterium tuberculosis
was suspended and centrifuged at 20,360 ×
g
. The supernatant liquid from this centrifugation was centrifuged at 56,550 ×
g
to remove the larger particles, and the supernatant liquid from this was centrifuged at 144,000 ×
g
to obtain a ribosomal fraction. The sediments from the first two centrifugations were highly immunogenic, but the ribosomal fraction showed only slight capacity to immunize mice. However, when the ribosomal fraction was mixed with Freund's incomplete adjuvant, the immunogenic activity was equivalent to the particulate fraction from which it was prepared. To test the hypothesis that some membranous substance in the particulate fraction was acting as an adjuvant for the smaller particles in the ribosomal fraction, portions of the particulate fraction were treated separately with each of the membrane-disrupting agents, sodium deoxycholate, sodium lauryl sulfate, and 1
m
sodium chloride. The treated materials were then centrifuged at 144,000 ×
g
, and the sediments were tested for immunogenicity both with and without the addition of Freund's incomplete adjuvant. Without the adjuvant, the immunizing activities were very weak or absent; with the adjuvant, they were equivalent to that of the particulate fraction from which they were prepared. Other factors which have been found to damage or destroy membranes, such as freezing and thawing, and heat, also significantly decreased the immunogenic activity of the particulate fraction unless it was incorporated into Freund's incomplete adjuvant. The larger particles which sedimented at 56,550 ×
g
were also treated with sodium lauryl sulfate and sodium chloride. Again, immunogenicity was greatly reduced but was fully restored by use of Freund's incomplete adjuvant. The data suggest, then, that the immunizing component of the particulate fraction is a substance (ribosomal?) which sediments at 144,000 ×
g
, but for maximal immunizing activity a labile, possibly membranous, moiety of the mycobacterial cell, which has the properties of an adjuvant, is required.
Effect of Ethambutol on Nucleic Acid Metabolism in
Mycobacterium smegmatis
and Its Reversal by Polyamines and Divalent Cations
Authors: Forbes M. , Kuck N. A. , Peets E. A.
Published: January 2020

Forbes
, M. (Lederle Laboratories Division, Pearl River, N.Y.), N. A.
Kuck, and E. A. Peets
. Effect of ethambutol on nucleic acid metabolism in
Mycobacterium smegmatis
and its reversal by polyamines and divalent cations. J. Bacteriol.
89:
1299–1305. 1965.—
Mycobacterium smegmatis
, harvested from cultures inhibited by ethambutol and then suspended in drug-free medium, exhibited a prolonged lag before growth resumed. Polyamines and magnesium ions shortened this lag. Polyamines and magnesium added to the culture increased the minimal inhibitory concentration of the drug and reversed the inhibitory effect of the drug, even when added after the drug had already inhibited growth. When ethambutol was added to a culture in its exponential phase of growth, synthesis of protein and deoxyribonucleic acid (DNA), as measured by incorporation of S
35
and P
32
, continued for 3 hr at a rate slightly less than in the control cells and then essentially ceased. Synthesis of ribonucleic acid (RNA) was depressed, but it proceeded even after protein synthesis had ceased. Even though the synthesis of RNA continued, the net RNA decreased, and inhibited cells became deficient in RNA. Polyamines and divalent cations, which reverse the inhibitory effect of the drug, have been reported to be involved in nucleic acid turnover. These considerations suggested that ethambutol may exert its inhibitory effect by interfering with a function of cellular polyamines and divalent cations in RNA metabolism.
Flagella of
Salmonella typhimurium
Spheroplasts
Authors: Vaituzis Z. , Doetsch R. N.
Published: January 2020

Vaituzis
, Z. (University of Maryland, College Park),
and R. N. Doetsch
. Flagella of
Salmonella typhimurium
spheroplasts. J. Bacteriol.
89:
1586–1593. 1965.—The flagella of penicillin-induced spheroplasts of
Salmonella typhimurium
were examined by electron and light microscopy. The process of spheroplast formation was followed for a period of 20 hr from its inception. Flagella were found to be confined to those areas of the spheroplast where cell-wall fragments remained. Flagella disappeared as the spheroplasts aged. Spheroplasts produced from nonflagellated organisms were found incapable of synthesizing flagella. Upon inactivation of the penicillin, however, flagella again were synthesized by spheroplasts during reversion to their original rod form. Flagella formation, it is suggested, is dependent on prior synthesis of the normal cell wall. The morphology of the microorganisms at the time of appearance of new flagella is described.
Isolation of Antigens ofPasteurella pestisI. Lipopolysaccharide-Protein Complex and R and S Antigens
Authors: Larrabee Allan R. , Marshall John D. , Crozier Dan
Published: January 2020

Larrabee, AllanR. (Fort Detrick, Frederick, Md.),John D. Marshall, and Dan Crozier. Isolation of antigens ofPasteurella pestis. I. Lipopolysaccharide-protein complex and R and S antigens. J. Bacteriol.90:116–119. 1965.—Pasteurella pestiscontains at least 18 different antigens, 2 of which will protect experimental animals from challenge infection. A specific polysaccharide isolated and described as a hapten was isolated as a complete antigen. Two additional antigens were isolated fromP. pestis. The preparation of antisera directed against these three antigens and the content of protein, lipid, and carbohydrate of each preparation were studied. None of the preparations will protect mice from challenge infection with virulentP. pestis. A basis for naming the new antigens which does not conflict with previously published designations is presented.
Persistent Herpes Simplex Virus Infection In Vitro with Cycles of Cell Destruction and Regrowth
Authors: Hampar Berge , Copeland Mary Lou
Published: January 2020

Hampar, Berge(National Institute of Dental Research, Bethesda, Md.),and Mary Lou Copeland. Persistent herpes simplex virus infection in vitro with cycles of cell destruction and regrowth. J. Bacteriol.90:205–212. 1965.—The susceptibility of two Chinese hamster cell lines to herpes simplex virus (HSV) was studied from the time of their initiation through successive subcultures. The cells' susceptibility to the cytocidal effects of HSV decreased as the number of cell passages increased. During the early cell passages, the decrease in cell susceptibility to HSV was characterized by an increased time after infection for complete cell destruction to occur, with a concomitant increase in the period when virus could be recovered from supernatant fluids. This was followed by a number of cell passages during which persistent HSV infections were established. The persistent infections were characterized by (i) cycles of virus synthesis and cell destruction followed by regrowth of the cells, (ii) initiation and maintenance under conditions optimal for cell growth in the absence of antibody, (iii) the cells' ability to be passaged while still maintaining their cycling patterns, (iv) a relationship between virus synthesis and cell proliferation, and (v) inability of long-term treatment with antibody to “cure” the persistent infections. The unique characteristics of this HSV infection were compared with other persistent in vitro viral infections.
Taxonomy of
Clostridium bifermentans
and
Clostridium sordellii
III. Agglutinability of Heat-Resistant Substrains of
Clostridium sordellii
Authors: Huang C. T. , Tamai Kenzo , Nishida Shoki
Published: January 2020

Huang
, C. T. (Kanazawa University, Kanazawa, Japan),
Kenzo Tamai, and Shoki Nishida
. Taxonomy of
Clostridium bifermentans
and
Clostridium sordellii
, III. Agglutinability of heat-resistant substrains of
Clostridium sordellii
. J. Bacteriol.
90:
391–394. 1965.—By cross-agglutination tests with
Clostridium bifermentans
and
C. sordellii
antisera, the heat-resistant substrains from each pathogenic strain of
C. sordellii
were found to possess antigens of
C. bifermentans
in addition to displaying changes in biological activities. The agglutinability and biological activities varied with the sporulating potency acquired. Agglutinin-absorption tests further proved that heat-resistant substrains of
C. sordellii
were immunologically identical to
C. bifermentans
.
Accumulation of Ribonucleoprotein Particles in a Relaxed Mutant of
Escherichia coli
Authors: Sypherd Paul S.
Published: January 2020

Sypherd, Paul
S. (University of California, San Diego). Accumulation of ribonucleoprotein particles in a relaxed mutant of
Escherichia coli
. J. Bacteriol.
90:
403–410. 1965.—The synthesis of ribonucleic acid during amino acid deprivation of a “relaxed” mutant was investigated. Aspects of the stability of the macromolecular ribonucleic acid (RNA) were studied, and standard conditions were established to allow maximal recovery of the larger RNA's (i.e., 16
S
and 23
S
). These RNA's, representing 75% of the total RNA produced during starvation, were present in particles with nominal
S
-values of 20, 30, and 43. The particles are extremely sensitive to nuclease action, being completely destroyed in the presence of 2 μg/ml of pancreatic ribonuclease at 15 C for 30 min. The particles containing the bulk of the RNA were shown to be ribonucleoprotein, consisting of 26 to 28% protein by weight. It was shown that no mature 70
S
ribosomes were formed during the accumulation of the lighter, protein-deficient particles.
Cytopathogenic Mycoplasmas Associated with Two Human Tumors I. Isolation and Biological Aspects
Authors: Armstrong D. , Henle G. , Somerson N. L. , Hayflick L.
Published: January 2020

Armstrong, D. (The Children's Hospital of Philadelphia, Philadelphia, Pa.), G.Henle, N. L. Somerson, and L. Hayflick. Cytopathogenic mycoplasmas associated with two human tumors. I. Isolation and biological aspects. J. Bacteriol.90:418–424. 1965.—Mycoplasmas were isolated from cell cultures of two benign human tumors. The first isolate contained two mycoplasmas, one a well-known human species (Mycoplasma hoministype I) and frequent tissue culture contaminant, and the other a recently reported new type. The second isolate was a mycoplasma of the newly described type. The mycoplasmas could be reisolated, after one or more passages through tissue culture, from extracts of the original tumor tissue. The relationship of the organisms to the neoplasms remains obscure. Both isolates produce cytopathic effect (CPE) and acidification of medium in a variety of tissue cultures. The CPE may be diminished, but not abolished, by increasing concentrations of arginine in the tissue culture media. Infection of various tissue cultures with the mycoplasmas did not result in interference to super-infection with vesicular stomatitis virus.
Evidence of Lysogeny in Derivatives of
Escherichia coli
Authors: Frampton E. W. , Brinkley B. R.
Published: January 2020

Frampton
, E. W. (The University of Texas M. D. Anderson Hospital and Tumor Institute, Houston),
and B. R. Brinkley
. Evidence of lysogeny in derivatives of
Escherichia coli
. J. Bacteriol.
90:
446–452. 1965.—Exposure of cultures of several thymine-requiring derivatives of
Escherichia coli
strain 15 to radiation [X rays or ultraviolet (UV)] resulted in an increased synthesis of ribonucleic acid (RNA) as measured by the incorporation of radioactive uridine. In addition to radiation, mitomycin C (5 or 25 μg/ml) or growth in the absence of thymine also stimulated RNA synthesis in cultures in which the bulk of RNA synthesis was terminated by a shift-down in growth conditions. RNA purified from X-irradiated bacteria was resolved on columns of methylated serum albumin and yielded an elution profile which appeared similar to RNA synthesized by phage-infected bacteria. Electron microscopic examination of cultures induced to lyse by exposure to UV radiation, or by growth in the presence of 5-bromouracil before exposure to radiation (X rays or UV), showed the presence of mostly incomplete phage particles.
Effect of Ribonucleic Acid Phage Superinfection on Lysis-Inhibited
Escherichia coli
Authors: Groman Neal B. , Suzuki Grace
Published: January 2020

Groman, Neal
B. (University of Washington, Seattle),
and Grace Suzuki
. Effect of ribonucleic acid phage superinfection on lysis-inhibited
Escherichia coli
. J. Bacteriol.
90:
1007–1012. 1965.—Induced culturesof
Escherichia coli
K-12(λ112)F
+
were superinfected with ribonucleic acid phage f2 at various times to test for the specificity of lysis inhibition and the concurrent inhibition of growth. When f2 superinfection occurred within 90 min after induction, lysis was observed in normally lysis-inhibited cultures. Later superinfections produced very little lysis. Following early superinfection, both λ112 and f2 phages were produced in induced cells. When superinfection occurred during the period in which growth was inhibited, f2 production was totally inhibited. The inhibition of f2 was not due to its inability to adsorb, nor was it due to damage inflicted on cells by ultraviolet irradiation or to exhaustion of the medium. The data suggest that inhibition of lysis of induced K-12(λ112)F
+
is phage-specific, whereas the accompanying inhibition of growth is nonspecific.
Electron Microscopy of Chromatophores of
Rhodopseudomonas spheroides
Authors: Gibson K. D.
Published: January 2020

Gibson
, K. D. (St. Mary's Hospital Medical School, London, England). Electron microscopy of
Rhodopseudomonas spheroides
. J. Bacteriol.
90:
1059–1072. 1965.—Fixed and stained chromatophores and whole cells of anaerobically grown
Rhodopseudomonas spheroides
were examined in thin sections in the electron microscope. Both purified chromatophores and intracellular membrane-bound vesicles had exactly the same appearance, namely that of spheres or ellipsoids with a thin electron-dense shell surrounding an electron-lucent interior. The distribution of diameters in the two types of structure was also found to be the same, and was compatible with a normal distribution, with a mean of 570 A and a standard deviation 40 A. Negatively stained chromatophores appeared like discs or collapsed spheres. The presence of invaginations of the cytoplasmic membrane in this species was confirmed, and a new structure resembling a twin chromatophore was observed. The bearing of these results on theories of the origin of chromatophores is discussed, and it is concluded that they offer some support for each one of the three main theories about the origin of particulate organelles.
Effect of Particle Aggregation on the Survival of Irradiated Vaccinia Virus
Authors: Galasso G. J. , Sharp D. G.
Published: January 2020

Galasso
, G. J. (University of North Carolina School of Medicine, Chapel Hill),
and D. G. Sharp
. Effect of particle aggregation on the survival of irradiated vaccinia virus. J. Bacteriol.
90:
1138–1142. 1965.—The survival curve (plaque titer versus time) of vaccinia virus irradiated with ultraviolet light was found to be strongly dependent, in both shape and general slope, on the degree of aggregation among the virus particles. When special care was taken to produce completely dispersed virus, a straight steep line resulted. Some severely aggregated preparations produced a straight line also, but of much less slope. Thus, the straight line, often taken as evidence of complete dispersion, is not a reliable measure for vaccinia virus. None of the experimental curves resembled the classical multihit curve predicted by the Poisson function for the behavior of uniformly aggregated virus. The aggregation was observed, by electron microscopy, to be nonuniform, and of such a distribution that the survival curves can be qualitatively accounted for in terms of multiplicity reactivation of irradiated virus within cells that receive groups of two or more particles. The greatly increased survival value of aggregates of virus, which indicates multiplicity reactivation, is worthy of note.
Development of Competence of
Haemophilus influenzae
Authors: Spencer Hugh T. , Herriott Roger M.
Published: January 2020

Spencer, Hugh
T. (The Johns Hopkins University School of Hygiene and Public Health, Baltimore, Md.),
and Roger M. Herriott
. Development of competence of
Haemophilus influenzae
. J. Bacteriol.
90:
911–920. 1965.—A chemically defined nongrowth medium was developed for the induction of competence of
Haemophilus influenzae
by a stepdown procedure. Cells grown logarithmically in Heart Infusion Broth became competent after being transferred to a medium which consisted of amino acids, sodium fumarate, and inorganic salts. Chloramphenicol (2 μg/ml) or
l
-valine (1 μg/ml) in the nongrowth medium inhibited development of competence. The inhibitory action of
l
-valine was reversed by comparable concentrations of
l
-isoleucine. Kinetic studies of the development of competence showed a variable capacity of competent cells to take up deoxyribonucleic acid and reaffirmed earlier findings that competence was not transmissible in
H. influenzae
. Addition of nicotinamide adenine dinucleotide, thiamine, calcium pantothenate, uracil, and hypoxanthine to the medium for competence resulted in a minimal growth medium in which reduced levels of competence were developed.
Effect of 5-Fluorouracil on the Growth of Bacteriophage R17
Authors: Graham A. F. , Kirk Clare
Published: January 2020

Graham, A. F. (The Wistar Institute of Anatomy and Biology, Philadelphia, Pa.),and Clare Kirk. Effect of 5-fluorouracil on the growth of bacteriophage R17. J. Bacteriol.90:928–935. 1965.—When added toEscherichia coliwithin 2 min after phage R17, 5-fluorouracil (FU), at a concentration of 10−4m, completely inhibited the synthesis of infectious ribonucleic acid (RNA) and phage. If the addition of FU was made later than 5 min after infection, infectious RNA synthesis was blocked but infectious phage was still formed; the infectious RNA made before the addition of FU continued to be incorporated into mature phage. These properties of the inhibitor were used to determine the kinetics of phage RNA synthesis and the size of the phage precursor RNA pool. At a concentration of 2.2 × 10−5mFU, the yield of phage was reduced to 15% of that in an uninhibited control, 28% of the phage RNA uracil was replaced with FU, and the specific infectivity of the phage was unaltered.
Polarity of Chromosome Replication inNeisseria meningitidis
Authors: Jyssum Kaare
Published: January 2020

Jyssum, Kaare(University of Oslo, Oslo, Norway). Polarity of chromosome replication inNeisseria meningitidis. J. Bacteriol.90:1182–1187. 1965.—Relative frequencies of various genetic markers in the deoxyribonucleic acid ofNeisseria meningitidisin exponential- and stationary-growth phases were compared by use of a transformation system. On the basis of an analysis of eight genetic markers, including a competence factor, it is assumed that a polarity exists in the chromosome replication. A genetic map has been constructed according to the model of Yoshikawa and Sueoka. Chromosome replication has been compared in genetically competent and genetically incompetent strains. The change from genetic competence to genetic incompetence seems to result in a change in the replication of the chromosome. The results are discussed in relation to findings from other transformation systems, particularly that ofBacillus subtilis.
Experimental Salmonellosis VII. In Vitro Transfer of Cellular Immunity by Ribosomal Fraction of Mouse Mononuclear Phagocytes
Authors: Sato Ichiei , Mitsuhashi Susumu
Published: January 2020

Sato, Ichiei
(Gunma University, Maebashi, Japan),
and Susumu Mitsuhashi
. Experimental salmonellosis. VII. In vitro transfer of cellular immunity by ribosomal fraction of mouse mononuclear phagocytes. J. Bacteriol.
90:
1194–1199. 1965.—The mononuclear phagocytes (termed monocytes) of mice hyperimmunized with live vaccine of
Salmonella enteritidis
inhibited the intracellular growth of virulent strain 116–54 of
S. enteritidis
. Also, the monocytes withstood the degeneration of cells caused by the phagocytosis of bacteria in the absence of immune serum in the tissue culture medium, termed cellular immunity. When the nonimmune monocytes were incubated with the ribosomal fraction of immune monocytes, obtained from the abdominal cavity of mice hyperimmunized with live vaccine of
S. enteritidis
, they acquired cellular immunity, but the monocytes did not acquire immunity when ribosomal fractions from normal mouse monocytes or from the monocytes of mice immunized with killed vaccine of
S. enteritidis
were used. The transfer agent present in the ribosomal fraction of immune monocytes was inactivated by treatment with ribonuclease but not with deoxyribonuclease or with trypsin.