bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Salmonellosis VII. Comparison of the Immunizing Effect of Live Vaccine and Materials Extracted from
Salmonella enteritidis
Authors: Kawakami Masaya , Osawa Nobutaka , Mitsuhashi Susumu
Published: January 2020

Kawakami, Masaya
(Gunma University, Maebashi, Japan),
Nobutaka Osawa, and Susumu Mitsuhashi
. Experimental salmonellosis. VII. Comparison of the immunizing effect of live vaccine and materials extracted from
Salmonella enteritidis
. J. Bacteriol.
92:
1585–1589. 1966.—Attempts were made to isolate the factors of live vaccine which immunize against
Salmonella enteritidis
infection in mice. Some effective substances were found in cellular extracts of this organism when those extracts were prepared by mild procedures. One of these substances was a heat-labile toxin (toxin L), which was found in an earlier study to be homogeneous as evidenced by chromatographic, ultracentrifugal, and serological analyses and which was phospholipoprotein in nature. Mice immunized with “toxin L” were protected against a 10 MLD challenge infection with a virulent strain to the same extent as animals immunized with live vaccine of an attenuated strain, SER. However, no agglutinin could be detected in sera of the animals given “toxin L.” Another effective substance, endotoxin, a heat-stable toxin, which was extracted from the same organisms, demonstrated poor protective effect. Possible mechanisms of immunization with live vaccine in
S. enteritidis
infection in mice are discussed.
Differentiation of Cariogenic Streptococci by Fluorescent Antibody
Authors: Jablon James M. , Zinner Doran D.
Published: January 2020

Jablon, J. M. (University of Miami, Miami, Fla.),and D. D. Zinner. Differentiation of cariogenic streptococci by fluorescent antibody. J. Bacteriol.92:1590–1596. 1966.—Eight strains of streptococci were isolated from human carious lesions by the fluorescent-antibody (FA) technique. Seven of these strains produced experimental caries in hamsters or rats maintained on a high sucrose diet. The eighth strain was noncariogenic in animals but possessed some antigenic components in common with the cariogenic strains. On the basis of antigen-antibody reactions by microprecipitin and agar-gel diffusion patterns, the strains were divided into four groups; these groups differed with regard to their cariogenic activity in hamsters. Fluorescein-conjugated antisera, prepared against the human strains, showed some cross-reactions which interfered with the efficacy of the FA technique in differentiating between the related streptococcal groups. To eliminate these cross-reactions, a small amount of related-strain antisera was added to the fluorescein-conjugated antisera to the cariogenic strains. This technique is effective in blocking cross-reactions and should be tried wherever cross-reactions are encountered in the FA technique.
L Form of
Neisseria gonorrhoeae
Authors: Roberts Richard B.
Published: January 2020

Roberts, Richard
B. (Walter Reed Army Institute of Research, Washington, D.C.). L form of
Neisseria gonorrhoeae
. J. Bacteriol.
92:
1609–1614. 1966.—L forms were produced by the penicillin gradient plate technique from a recently isolated strain of
Neisseria gonorrhoeae
. To date, these L forms have had 30 serial passages on medium containing penicillin. Stabilized L forms developed on penicillin-free medium after 10 or more passages in the presence of penicillin. Morphological characteristics of these organisms were identical to L forms of meningococci. Medium and environmental conditions necessary for optimal growth included: Brain Heart Infusion of
p
H 7.2 to 7.4, 1.1 to 1.3% agar, 10 to 20% sucrose, 10 to 20% horse serum, temperature at 35 to 36 C, and increased CO
2
tension (candle jar). L forms were more resistant than the parent gonococcus to penicillin, ampicillin, methicillin, cycloserine, and cephalothin, whereas both organisms had similar sensitivities to bacitracin, vancomycin, ristocetin, novobiocin, tetracycline, and erythromycin. Revertant gonococci were produced on penicillin-free medium from L forms which had had 1, 5, and 10 serial passages. Morphology and fermentative reactions of revertant strains were identical to those of the parent gonococcus. Revertant strains produced L forms more readily than the parent organism; in fact, L forms from certain revertants did not require penicillin, but only serum and sucrose for their production and propagation on artificial medium.
Differential Analysis of Sulfhydryl and Disulfide Groups of Intact Spores
Authors: Blankenship L. C. , Pallansch M. J.
Published: January 2020

Blankenship
, L. C. (Eastern Utilization Research and Development Division, Washington D.C.),
and M. J. Pallansch
. Differential analysis of sulfhydryl and disulfide groups of intact spores. J. Bacteriol.
92:
1615–1617. 1966.—Fluorescence quenching of fluorescein mercuric acetate in alkaline medium (1
n
NaOH) was found to be an accurate, sensitive method for differential analysis of sulfhydryl and disulfide groups of intact bacterial spores. Disulfide content of three species of spores was found to be slightly higher than reported by other workers. A significant increase in sulfhydryl group concentration was observed after physiological germination, indicating participation of a disulfide-reducing system in the germination process.
Kinetics of Fungal Growth and Phosphatase Formation in
Aspergillus nidulans
Authors: Dorn G. , Rivera W.
Published: January 2020

Dorn
, G. (Albert Einstein College of Medicine, New York, N.Y.),
and W. Rivera
. Kinetics of fungal growth and phosphatase formation in
Aspergillus nidulans
. J. Bacteriol.
92:
1618–1622. 1966.—A liquid culture system is described for growing
Aspergillus nidulans
in a manner amenable to kinetic studies. Changes in dry weight, protein, deoxyribonucleic acid (DNA), inorganic phosphate, alkaline phosphatase, and acid phosphatase activity were followed over a 40-hr interval. In both limiting- and high-phosphate media, the doubling time of DNA during the logarithmic phase was 3.5 ± 0.5 hr. Of the four phosphatases which have been found in this fungus, three were markedly derepressed by low levels of inorganic phosphate.
Production, Purification, and Composition of Staphylococcal α Toxin
Authors: Coulter John R.
Published: January 2020

Coulter, John
R. (Institute of Medical and Veterinary Science, Adelaide, Australia). Production, purification, and composition of staphyloccocal α toxin. J. Bacteriol.
92:
1655–1662. 1966—Pure staphylococcal α toxin has been prepared in quantities suitable for chemical, biological, and clinical characterization. Purification was achieved by acid-methanol precipitation, chromatography on G100 Sephadex, and electrophoresis in G100 Sephadex. We recovered 25% of the crude toxin in pure form, a yield of 12 mg/liter of crude culture supernatant fluid. The pure material gave a single line on gel diffusion and on immunoelectrophoresis and gave a single symmetrical peak in the ultracentrifuge. The α toxin was highly unstable, with a half-life of 3 days at 0 C (
p
H 7.8); solutions of it could not be frozen, and we found no method to stabilize it. On standing, a thready precipitate appeared; it was inactive against rabbit red cells, was not lethal to rabbits, but was able to elicit specific anti-α antibody production in the rabbit. There is evidence that α toxin is an associating molecule, with a mean sedimentation coefficient of approximately 3.0 and a molecular weight of approximately 30,000. The lowest molecular weight, found by equilibrium ultracentrifugation, was 21,200 ± 400. The amino acid composition was determined, and the high positive charge was explained by the presence of lysine, arginine, and histidine, and by amination of the aspartic and glutamic acid residues. Histidine and arginine were shown to be N-terminal amino acids, a fact which suggests the presence of two polypeptide chains. No carbohydrate was present. The ultraviolet absorption spectrum showed a maximum at 274.5 mμ, a minimum at 251.5 mμ, and a shoulder at 292 mμ. The toxin was without proteolytic or phospholipase activity, and its highly specific action on cell membranes still remains unexplained.
Mutations Determining Mitomycin Resistance
in Bacillus subtilis
Authors: Iyer V. N.
Published: January 2020

Iyer
, V. N. (Microbiology Research Institute, Canada Department of Agriculture, Ottawa, Canada). Mutations determining mitomycin resistance in
Bacillus subtilis
. J. Bacteriol.
92:
1663–1669. 1966.—The pattern of development of genetic resistance in
Bacillus subtilis
to mitomycin C was studied, and spontaneous single and multistep mutants were obtained. The transmission and expression of these mutations in sensitive strains proved possible by means of genetic transformation. The mutations were genetically studied in relation to a chromosomal mutation,
mac-1
, which confers resistance to the macrolide antibiotic erythromycin and which has been previously localized in the early-replicating segment of the
B. subtilis
chromosome. The results indicate that all of three primary mutations studied in this manner, as well as a secondary and tertiary mutation derived from one of the primary mutations, are clustered in this early-replicating segment. It appears that the secondary and tertiary mutations enhance the resistance conferred by the primary mutation, apparently without themselves conferring any resistance.
Nature of Ribonucleic Acid Stimulated by Streptomycin in the Absence of Protein Synthesis
Authors: Freda Celia E. , Cohen Seymour S.
Published: January 2020

Freda, Celia
E. (University of Pennsylvania School of Medicine, Philadelphia),
and Seymour S. Cohen
. Nature of ribonucleic acid stimulated by streptomycin in the absence of protein synthesis. J. Bacteriol.
92:
1680–1688. 1966.—The ribonucleic acid (RNA) synthesized in a thymineless, arginineless, uracil-less
Escherichia coli
strain 15 in the absence of arginine was characterized by sucrose density gradient centrifugation. About 60% of this RNA had sedimentation rates in the range between 4
S
and 16
S
, and the remainder was comprised of the 23
S
and 16
S
ribosomal components. On addition of streptomycin for 1 hr in the absence of the amino acid, there was an inhibition of synthesis of material of 4
S
to 16
S
, whereas 16
S
RNA was slightly stimulated. Between 1 and 3 hr after addition of the antibiotic, during the precipitous killing of the bacteria in the arginine-deficient culture, the synthesis of 16
S
ribosomal RNA was specifically and sharply stimulated.
Tryptophan Transport in
Neurospora crassa
I. Specificity and Kinetics
Authors: Wiley W. R. , Matchett W. H.
Published: January 2020

Wiley
, W. R. (Battelle Memorial Institute, Richland, Wash.),
and W. H. Matchett
. Tryptophan transport in
Neurospora crassa
. I. Specificity and kinetics. J. Bacteriol.
92:
1698–1705. 1966.—The transport of tryptophan in
Neurospora crassa
is mediated by a distinct stereospecific system which is chemically specific for a family of neutral amino acids. The process shows typical saturation kinetics and a sharp decrease in the rate of tryptophan uptake at low temperatures. The Q
10
for the process is approximately 2 between 20 and 30 C. The apparent
K
m
for uptake is 5 × 10
−5
m
. Leucine and phenylalanine competitively inhibit the rate of tryptophan transport; the
K
i
values are 1.1 × 10
−4
m
and 4.0 × 10
−5
m
, respectively. These data are interpreted as evidence that these amino acids are transported by the same transport site(s). Inhibition studies with amino acids and other compounds structurally related to leucine and phenylalanine suggest that an uncharged side chain and an α amino group, next to a carboxyl, represent three attachment points for the uptake site.
Characterization of Hog Cholera Virus I. Determination of Buoyant Density
Authors: Horzinek Marian
Published: January 2020

Horzinek, Marian
(Tierärztliche Hochschule, Hannover, West Germany). Characterization of hog cholera virus. I. Determination of buoyant density. J. Bacteriol.
92:
1723–1726. 1966.—Hog cholera virus was subjected to cesium chloride density gradient centrifugation. Most of the infectious activity was detected in fractions with densities between 1.15 and 1.20 g/ml, with a peak at 1.16 g/ml. Infectivity was assayed by use of either the exaltation of Newcastle disease virus method or the hemagglutination exaltation and inhibition of cytopathic effect method.
Persistent Cyclic Herpes Simplex Virus Infection In Vitro IV. Changes in the Severity of the Infections in the Presence of Antibody
Authors: Hampar Berge
Published: January 2020

Hampar, Berge
(National Institute of Dental Research, Bethesda, Md.). Persistent cyclic herpes simplex virus infection in vitro. IV. Changes in the severity of the infections in the presence of antibody. J. Bacteriol.
92:
1741–1747. 1966.—The severity of persistent herpes simplex virus (HSV) infections maintained in the presence of viral antibody (AB) changed with time. These changes could be divided into three distinct phases during which the severity of the infections were maintained at low (phase 1), high (phase 2), and intermediate (phase 3) levels. Paralleling these changes was the appearance in the cultures of a new HSV variant which induced the formation of giant cells. The changes in the severity of the infections were attributable to three factors. The first was the presence in the cultures of virus-resistant cells. The second was the suppressive effects due to virus neutralization by the AB. The third was the inherent properties of each HSV variant which determined the amount of virus remaining in an infectious form in the presence of AB. Finally, the period of “exacerbation” in vitro (phase 2) was compared with recurrent episodes in human herpes infection.
Fine Structure of Sporulation in
Bacillus cereus
Grown in a Chemically Defined Medium
Authors: Ellar D. J. , Lundgren D. G.
Published: January 2020

Ellar
, D. J. (Syracuse University, Syracuse, N.Y.),
and D. G. Lundgren
. Fine structure of sporulation in
Bacillus cereus
grown in a chemically defined medium. J. Bacteriol.
92:
1748–1764. 1966.—A study was made of the fine structure of sporulating cells of
Bacillus cereus
grown in a chemically defined medium. The developmental stages of sporulation occurred in a fairly synchronous manner and were complete by 14 hr. This time period was shortened when spore wall peptide components were added to the medium, but the addition had no effect upon fine structure except to thicken the cell wall. Sporulation could be separated into six morphological stages which generally agreed with those published for other sporulating bacteria. The initiation of the spore (forespore) septum takes the form of an inward folding of the cytoplasmic membrane toward the pole of the cell. The inward folding forms a characteristic Y-shaped membrane structure enclosing an area within which vesicles are found. These vesicles comprise the perisporal mesosome of the cell. The membranes on opposite sides of the cell progress toward the cell center where they fuse to form the double unit membrane of the spore septum. As the proliferation of the spore septum continues, the vesicular areas move towards the pole. The end result is a double forespore membrane which completely encloses a part of the vegetative cell's chromatin. Sporal mesosomes, as well as membrane vesicles, are involved in the proliferation of the forespore. Vesicles are generally bounded by a single unit membrane, whereas in the sporal mesosomes several unit membranes are arranged concentrically. The latter become associated with the segregation of a portion of the nuclear material into the forespore region of the cell.
Electron Microscopy of the Cell Envelope of
Ferrobacillus ferrooxidans
Prepared by Freeze-Etching and Chemical Fixation Techniques
Authors: Remsen Charles , Lundgren D. G.
Published: January 2020

Remsen
, C. C. (Swiss Federation Institute of Technology, Zurich, Switzerland),
and D. G. Lundgren
. Electron microscopy of the cell envelope of
Ferrobacillus ferrooxidans
prepared by freeze-etching and chemical fixation techniques. J. Bacteriol.
92:
1765–1771. 1966.—A comparison was made of the fine structure of the cell envelope of the gram-negative bacterium
Ferrobacillus ferrooxidans
when cells were prepared for microscopy by freeze-etching and chemical fixation techniques. Cell envelopes of chemically fixed cells appeared as five separate layers distinguishable by their location and electron density. Frozen-etched cells showed a three-layered complex with each layer measuring approximately 100 A in thickness. The latter technique is considered to be “artifact-free” and, as a technique, yields purely morphological information on the natural state. The three layers revealed by freeze-etching are: the outer layer, a lipoprotein-lipopolysaccharide layer; the middle layer, a layer composed of globular protein attached to fibrillar mucopeptide; and the innermost layer, the cytoplasmic membrane. The latter was covered with 100 to 120 A particles. The relationship of the aforementioned layers to those seen in chemically fixed cells is discussed.
Utility of Sodium Hypochlorite for Ultrastructure Study of Bacterial Spore Integuments
Authors: Rode L. J. , Williams M. Glenn
Published: January 2020

Rode
, L. J. (The University of Texas, Austin),
and M. Glenn Williams
. Utility of sodium hypochlorite for ultrastructure study of bacterial spore integuments. J. Bacteriol.
92:
1772–1778. 1966.—Spores of
Bacillus megaterium
are partially dissolved by sodium hypochlorite. Spore integuments become visible during the dissolution, and ultrastructural features may be detected. Three distinct integument types are described for
B. megaterium
QM B1551 with the use of this technique. Since a variety of microbial cells are affected by sodium hypochlorite, its use may be applicable to ultrastructure study of cells other than bacterial spores.
Structure of the Ribonucleic Acid Bacteriophage R17
Authors: Vasquez Cesar , Granboulan Nicole , Franklin Richard M.
Published: January 2020

Vasquez, Cesar
(Institut de Recherches sur le Cancer, Villejuif, Seine, France),
Nicole Granboulan, and Richard M. Franklin
. Structure of the ribonucleic acid bacteriophage R17. J. Bacteriol.
92:
1779–1786. 1966.—The morphology of bacteriophage R17 was studied by electron microscopy of negatively stained virions. The hexagonal shape, the presence of a maximum of 10 units at the periphery, and especially the observation of central fivefold points of symmetry with neighboring five and six coordinated units indicated icosahedral symmetry with 32 morphological units. Although the exact shape of the polyhedron could not be specified, the number of morphological units agreed with the chemically estimated number of structural units.
Persistent Infection of Cells in Culture by Measles Virus I. Development and Characteristics of HeLa Sublines Persistently Infected with Complete Virus
Authors: Rustigian Robert
Published: January 2020

Rustigian, Robert(Tufts University School of Medicine, Boston, Mass.). Persistent infection of cells in culture by measles virus. I. Development and characteristics of HeLa sublines persistently infected with complete virus. J. Bacteriol.92:1792–1804. 1966.—After the development of marked cytopathic effects in HeLa cultures infected with the Edmonston strain of measles virus, renewed cell growth occurred, and HeLa sublines persistently infected with measles virus were obtained. Persistent infection has occurred in a large fraction of the cells of infected clonal lines for more than 300 to 500 cell generations during a period of 6 years. One mechanism by means of which infection was maintained in the clonal lines is transmission of virus or viral subunits from cell to cell at division. Continued subculture of the persistently infected populations resulted in the virtual disappearance of cytopathic effects, a marked decrease in the amount of extracellular virus, and alterations in the cytopathogenicity of virus recovered from persistently infected populations. The intracellular virus-host cell events in late passages of the infected clonal lines appeared to be similar to those in cells of primary infected cultures at early stages of infection, as judged by the pattern of viral immunofluorescence and the very low incidence of cells with intranuclear inclusion bodies. Cultures of the persistently infected clonal lines were highly resistant to super infection by parent Edmonston virus. Cultures of one of these clonal lines were just as susceptible as normal HeLa cultures to vaccinia, herpes simplex, and polio type 2 viruses, and a simian agent, with a possible low degree of resistance to the simian agent.
Persistent Infection of Cells in Culture by Measles Virus II. Effect of Measles Antibody on Persistently Infected HeLa Sublines and Recovery of a HeLa Clonal Line Persistently Infected with Incomplete Virus
Authors: Rustigian Robert
Published: January 2020

Rustigian, Robert(Tufts University School of Medicine, Boston, Mass.). Persistent infection of cells in culture by measles virus. II. Effect of measles antibody on persistently infected HeLa clonal line persistently infected with incomplete virus. J. Bacteriol.92:1805–1811. 1966.—The effect of viral antibody on persistent infection of HeLa cells by the Edmonston strain of measles virus was investigated by culturing cells from three persistently infected clones in medium supplemented with human immune globulin. The three infected HeLa clones were isolated from a persistently infected parent line. Two sublines which were grown in the presence of measles antibody developed a nonyielder state, wherein there is no detectable virus infectious for normal HeLa cultures. There is, however, continued synthesis of intracellular viral antigen and formation of viral intracytoplasmic inclusion bodies. The development of a nonyielder state was associated with a marked decrease in the degree of hemadsorption in cultures of both sublines. Further studies of the viral properties of non-yielder HeLa cell populations were made with a clone obtained from one of these sublines by plating under antibody. Persistent infection in this line was characterized by synthesis of incomplete virus even when the cells were cultured thereafter in anti-body-free medium. This was evidenced by (i) failure to recover infectious virus from the clonal population despite continued formation of intracellular viral antigen and viral intracytoplasmic inclusion bodies in a majority of the cells, (ii) the presence of only a few cells with surface viral antigen(s) including hemagglutinin, and (iii) the relatively weak antibody response to viral envelope antigen(s) after injection of cells into guinea pigs.
Antibacterial Sensitivity of
Bifidobacterium
(
Lactobacillus bifidus
)
Authors: Miller Lawrence G. , Finegold Sydney M.
Published: January 2020

The antibacterial sensitivity patterns of gram-positive, nonsporeforming, anaerobic bacilli variously classed as
Lactobacillus bifidus, Actinomyces bifidus
, or
Bifidobacterium
were studied by the plate dilution method. A total of 34 strains, mostly from human feces, was studied. Three species,
B. longum, B. adolescentis
, and
B. bifidum
, were represented with 11, 11, and 6 strains, respectively. The other six strains fell into four other species. Most strains of all types resisted 100 μg/ml or more of neomycin, polymyxin B, and nalidixic acid. They were somewhat less resistant to kanamycin and still less so to streptomycin. All strains were inhibited by less than 1 μg/ml of penicillin G and erythromycin, by 3.1 units or less per ml of bacitracin, by 3.1 μg/ml or less of chloramphenicol, and by 6.2 μg/ml or less of tetracycline and lincomycin. Most strains were inhibited by 3.1 μg/ml of vancomycin. Results were very variable with cephalothin and nitrofurantoin, with some strains quite resistant. With half of the drugs tested, there were moderate differences in sensitivity between different species. These data are discussed in relation to the effect of antimicrobial agents on bifid bacilli in the normal human fecal flora, in relation to the implications thereof, and in relation to the usefulness of several agents (particularly neomycin, nalidixic acid, and polymyxin B) in selective media for
Bifidobacterium
.
Cell Permeability: a Factor in the Biotin-Oleate Relationship in
Lactobacillus arabinosus
II. Effect of Oleic Acid and Other Surfactants on Free Biotin Uptake
Authors: Waller James R. , Lichstein Herman C.
Published: January 2020

Bound biotin-saturated cells were incubated in the presence of biotin and glucose (37 C,
p
H 7.5) with or without oleic acid, Tween 20, 40, 60, and 80, Aerosol OT, sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide, Triton X-100, Non-Ion-Ox, and Haemo-Sol. With low concentrations (up to 5 μg/ml) and short reaction times (up to 10 min), oleic acid stimulated free biotin accumulation. Increased concentrations (10 to 50 μg/ml) or reaction times (10 to 30 min) caused progressive reductions in uptake or increased release of previously accumulated vitamin. Combination of Tween 40 (1 mg/ml) with oleic acid (up to 50 μg/ml) detoxified oleic acid and stimulated free biotin uptake. Oleic acid (5 μg/ml or more) reduced cell viability, an effect which was overcome by Tween 40. All other surfactants tested stimulated free biotin accumulation at sublethal concentrations. Aerosol OT and SDS exhibited the same degree of stimulatory activity as detoxified oleic acid; however, at concentrations higher than 200 μ
m
, a rapid decrease in vitamin accumulation was observed which paralleled that caused by increased oleic acid concentrations. The results suggest that oleic acid and other surfactants affect the permeability of cells of
Lactobacillus plantarum
(formerly called
L. arabinosus
) in a similar manner.
Thiobarbiturate-reacting Materials in Microorganisms
Authors: Vincent William F. , Cameron J. A.
Published: January 2020

The amount of thiobarbiturate-reacting material in 51 strains of bacteria and three yeasts was determined. Reactive material was found to be present in all of the gram-negative bacteria examined. It was assumed that the reactive material in this case was primarily 2-keto-3-deoxyoctonate (KDO), an eight-carbon sugar acid which is usually associated with the cell wall lipolysaccharide of members of the
Salmonella-Escherichia
group. Very little reactive material could be detected in the gram-positive species and yeasts that were examined. When expressed as per cent dry weight, the gram-negative bacteria exhibited about eight times more reactive material than the gram-positive species. It is suggested that the small amount of reactive material detected in gram-positive cells and yeasts is due to compounds other than KDO.
Constitutive and Induced Trehalose Transport Mechanisms in Spores of the Fungus
Myrothecium verrucaria
Authors: Mandels G. R. , Vitols Rasma
Published: January 2020

Trehalose is absorbed by two distinct systems—one constitutive, the other induced by turanose and to a lesser extent by nigerose but not by trehalose. The constitutive system is apparently mediated by a surface trehalase; the induced system has the characteristics of a permease. The specificity of the induced system is apparently limited to the α glucosyl-glucose or glucosyl-fructose linkage, because absorption of kojibiose, nigerose, maltose, isomaltose, turanose, sucrose, and melezitose, in addition to that of trehalose, was increased. Absorption of β-linked or of galactose-containing disaccharides was not increased. The constitutive and induced trehalose-absorbing systems differ in their activity, specificity, lability to acid treatment, effects of substrate concentration, and
p
H optima. Both systems require oxygen, and no marked differential effects of inhibitors were observed. The activity of the induced system is proportional to log turanose concentration (from about 1 to 300 μg/ml), and is an approximate linear function of time of exposure (from about 1 to 50 min). Accumulation of trehalose occurred against a concentration gradient in both systems but particularly in the induced. No leakage was observed. The activity of the induced system declined slowly upon removal of the inducer. Accumulated trehalose is metabolized after activation by azide as are the endogenous trehalose reserves. The accumulated trehalose appears to enter the endogenous trehalose pool found in these spores, although some data suggest it may be more accessible. Respiratory data indicate that absorbed trehalose is available for metabolism while in transit from the external membrane to the internal pool.
Heat-labile Enzymes in a Psychrophilic Bacterium
Authors: Purohit K. , Stokes J. L.
Published: January 2020

The oxidative and fermentative activities of a psychrophilic bacterium (strain 82), whose maximal growth temperature is 35 C, were completely destroyed by exposure of the cells to 46 C for about 1 hr, whereas those of mesophilicEscherichia coliwere unaffected. Similar results were obtained with cell-free extracts. In attempts to determine some of the specific enzymes inactivated in strain 82 by exposure to 46 C, it was found that reduced nicotinamide adenine dinucleotide oxidase was completely inactivated at 46 C in 2 hr. Also, cytochromecreductase was completely destroyed at 46 C in 1 hr and was 70% destroyed at 40 C in 2 hr. The heat lability of the latter may determine the maximal growth temperature of the organism. In addition, the results indicated that the enzymes of strain 82 involved in the clastic split of pyruvate to formate and acetate are inactivated by exposure to 46 C and that the lactic and glycerol dehydrogenases are more heat-labile than those inE. coli. Succinic, nicotinamide adenine dinucleotide phosphate-alcohol, and glucose-6-phosphate dehydrogenases, however, in both strain 82 andE. coli, were essentially unaffected by exposure to 46 C for 2 hr.
Cell Wall Constituents of
Leuconostoc citrovorum
and
Leuconostoc mesenteroides
Authors: Harney Sheila J. , Simopoulos Nicholas D. , Ikawa Miyoshi
Published: January 2020

The cell wall constituents of
Leuconostoc citrovorum
8082,
L. mesenteroides
10830a, and
L. mesenteroides
11449 have been ascertained. All three strains contained glycerol. Glucose and rhamnose were the major reducing sugar constituents. Alanine, glutamic acid, lysine, glucosamine, and muramic acid were the principal amino acids and amino sugars in all three strains. In addition, strain 10830a contained
l
-serine as a major cell wall component. Quantitative amino acid analyses indicate that glutamic acid, lysine, glucosamine, muramic acid, and serine may be present in the cell walls in equimolar amounts and that alanine is present in three to four times these quantities. The similarities and differences between the cell wall constituents of the leuconostocs and those of the lactobacilli and streptococci are discussed.
Effects of Oxygen and Heme on the Development of a Microbial Respiratory System
Authors: Jacobs N. J. , Maclosky E. R. , Conti S. F.
Published: January 2020

The effect of adding hemin to anaerobically grown cells of a strain of
Staphylococcus epidermidis
, which was heme-deficient due to anaerobic growth, has been examined. Cells grown anaerobically in media containing hemin exhibited a marked increase in several oxidative activities as compared with cells grown anaerobically without hemin. The respiratory activity of whole cells and a cyamide-sensitive reduced nicotinamide adenine dinucleotide oxidase activity of cell-free extracts were increased fourfold. The content of enzymatically reducible pigments which exhibit difference spectra similar to cytochromes
b
1
and
o
was also markedly increased. These pigments are mostly sedimented at 100,000 ×
g
(1 hr). Hemin also caused a marked increase in respiratory activity when added directly to the anaerobic culture after the period of growth, but did not cause a similar increase in respiration when added to washed, resting-cell suspensions. Under the latter conditions, heme pigments were formed which exhibited difference spectra similar to, but not identical with, the spectra of pigments found in anaerobic cells grown in the presence of hemin. When resting suspensions of cells grown anaerobically without hemin were exposed to air, a rapid fourfold increase in respiratory activity and a limited increase in cytochrome-like pigments occurred. The presence of the heme precursor Δ-aminolevulinic acid during this aeration resulted in a rapid and marked increase in heme pigments, but only a slight stimulation of respiratory activity. The possible implications of these results for the roles which heme and oxygen play in the development of the respiratory system of this organism are discussed.
Iron-chelating Hydroxamic Acid (Schizokinen) Active in Initiation of Cell Division in
Bacillus megaterium
Authors: Byers B. R. , Powell M. V. , Lankford C. E.
Published: January 2020

Bacillus megaterium
ATCC 19213 secretes a cell division-initiating “schizokinen” (SK) which accumulates during its culture cycle to a concentration inversely proportional to the iron added to a sucrose-mineral salts medium. Secreted SK was purified from culture filtrates as a red Fe (III) chelate, and a fraction with similar biological properties was obtained from whole cells. Infrared spectra of SK, and analyses of unhydrolyzed and acid-hydrolyzed preparations indicated it to be a secondary hydroxamate; visible absorption maxima of the ferric complex showed
p
H dependency typical of ferric monohydroxamates. Schizokinen preparations from cultures grown at “normal” and at low Fe concentrations were similar biologically and in certain of their chemical properties, but their

R
F

values and infrared spectra suggested nonidentity. Significant lag reduction of
B. megaterium
was effected by 0.2 mμg of SK per ml; the Fe (III)-SK chelate and “iron-free” SK were equally effective. A 50-mμg amount produced half-maximal growth response of the siderochrome auxotroph,
Arthrobacter
JG-9. Schizokinen also overcame ferrimycin A inhibition of three
Bacillus
species. These properties relate the
B. megaterium
schizokinen to the trihydroxamate siderochromes, although SK appears to be a monohydroxamate.
Genetically Alterable Transport of Amethopterin in
Diplococcus pneumoniae
I. Physiological Properties and Kinetics of the Wild-type System
Authors: Sirotnak Francis M. , Sargent M. Gay , Hutchison Dorris J.
Published: January 2020

A system of
H
3
-amethopterin uptake, physiologically and kinetically resembling active transport, has been described in
Diplococcus pneumoniae
. Uptake by this system has a
p
H optimum near 6.0, is temperature-dependent, requires a readily available source of energy, and conforms to Michaelis-Menten kinetics. The system showed a
K
m
of 0.9 × 10
−6
m
and a
V
max
of 1.9 × 10
−13
moles per min per mg (dry weight). Both folate and H
2
-folate compete with
H
3
-amethopterin for the same system, but to a limited degree. The intracellular concentration of
H
3
-amethopterin accumulated at equilibrium was 1.06 × 10
−9
moles/ml or fivefold the external concentration when the latter was limiting, but at least 60-fold the internal concentration attained solely by diffusion in the same time interval at 0 C.
Magnesium Starvation of
Aerobacter aerogenes
IV. Cytochemical Changes
Authors: Kennell David , Kotoulas Angeliki
Published: January 2020

A number of cytochemical changes were revealed by microscopic observations of
Aerobacter aerogenes
populations starving for Mg
++
. During the first few hours, while the synthesis of deoxyribonucleic acid (DNA) was paralleled by an increase in viable bacteria, the cells became progressively smaller. Subsequently, the number of viable cells in the culture remained constant in spite of continuing DNA synthesis, and the cells progressively elongated into filamentous forms. During this time, a second population of very small bacteria could be identified. These cells, whose number increased progressively, were inert with respect to (i) growth or reproduction when returned to a complete medium and (ii) biosynthetic activity as judged by autoradiographic estimation of uracil-
H
3
incorporation into nucleic acids. When observed by electron microscopy, many thin sections from bacteria that had been starved of Mg
++
for 20 hr appeared to be almost devoid of ribosomal particles. Thionine staining indicated that the inert cells contain DNA. Furthermore, the rate of DNA synthesis in the culture corresponded to the rate of accumulation of inert cells, suggesting that their presence can account for the difference between total DNA and viable count.
Antibodies in Histoplasmosis
Authors: Markowitz Harold
Published: January 2020

Production of precipitating and complement-fixing antibody in rabbits and other animals was induced by immunization with live yeast-phase cells of
Histoplasma capsulatum
. Results of studies of polysaccharide antigens from three strains of
H. capsulatum
, by quantitative complement-fixation with human and rabbit antisera, strongly suggest the presence of type specificity. The variations of titer during 11 weeks in one patient with histoplasmosis and the variations of titer among a group of patients with histoplasmosis were studied by use of quantitative complement-fixation tests.
Aflatoxin B
1
Uptake by
Flavobacterium aurantiacum
and Resulting Toxic Effects
Authors: Lillehoj E. B. , Ciegler A. , Hall H. H.
Published: January 2020

Removal of aflatoxin B
1
from liquid cultures by resting and growing cells of
Flavobacterium aurantiacum
NRRL B-184 was studied. Spectrophotometic and thin-layer techniques served as aflatoxin assays. Cells grown in the presence of 5 ppm or higher levels of aflatoxin developed aberrant morphological forms. These toxin concentrations partially inhibited growth, and the nature of the inhibition suggested that aflatoxin interfered with cell wall synthesis. Incubation of 1.0 × 10
11
resting cells per milliliter with 7.0 μg/ml of aflatoxin B
1
during a 4-hr period facilitated complete toxin removal from a buffered aqueous medium. Autoclaved cells and cell wall preparations could remove a fraction of the aflatoxin of a test system. However, the toxin removed by autoclaved cells and cell walls could be extracted by washing with water but the aflatoxin B
1
removed by intact cells could not be extracted into the liquid phase. The uptake of aflatoxin B
1
by resting cells was sensitive to temperature and
p
H. Ruptured preparations of
F. aurantiacum
were not able to remove or modify the aflatoxin in an aqueous solution.
Ultrastructure of the Membrane System in
Lactobacillus plantarum
Authors: Kakefuda Tsuyoshi , Holden Joseph T. , Utech Nedra M.
Published: January 2020

Electron microscopic study of
Lactobacillus plantarum
revealed mesosomes in different stages of maturation and structural relation with other cell organelles. Small, immature mesosomes were bounded by a prominent electron-dense layer with another extremely faint layer on the outside. This corresponds to the appearance of the cytoplasmic membrane. Large mature mesosomes were surrounded by a triple-layered unit membrane having electron-opaque layers of approximately equal density, suggesting that the composition of the boundary membrane alters during development of this structure. Three-dimensional observations derived from serial sections indicated that mesosomes always maintain a connection between the cytoplasmic membrane and the comparable layers of their boundary. The cytoplasmic membrane also consisted of a triple-layered unit membrane, the innermost layer of which was less electron-opaque and was usually hidden by the relatively dense background of the cytoplasm. The innermost layer of the cytoplasmic membrane was most clearly seen in plasmolyzed cells. Only mature mesosomes made distinct contacts with, or were partially immersed in, the nucleoplasm. The boundary of such mesosomes frequently seemed to be discontinuous, suggesting that the mesosome interior was in direct contact with the nucleoplasm. Mesosomes involved in cross-wall formation at a division plane increased in size and passed through a sequence of positions which led ultimately to an association with the nucleoplasms of the daughter cells. The inner surface of the cell wall was lined by a thin, electron-dense layer whose composition and function are unknown. Under the cultural conditions used, this organism regularly contained a polyphosphate granule.
Substructure of the Cytoplasmic Membrane of
Bacillus megaterium
I. Method for the Fractionation of “Ghosts”
Authors: Yamaguchi Tsutomu , Tamura Gakuzo , Arima Kei
Published: January 2020

A method of fractionation of “ghosts” was devised to identify the chemical components of the cytoplasmic membrane. The method consists of dialyzing the “ghosts” against distilled water, and then dissolving the ghosts in dilute alkali. The ghosts were fractionated into four fractions by use of differential centrifugation. The components of each fraction were analyzed in detail. The ratio of lipid to protein and content of carbohydrate were found to be different for the four fractions. The main two fractions (fractions 2 and 3) contained several types of materials. Fraction 2, which is soluble in alkali and sedimentable at 105,000 ×
g
, contained protein and lipid in the ratio of 2:1; ribonucleic acid was not detectable. Under the electron microscope, the ghosts appeared to have released the cell's cytoplasmic contents, but many small dense particles (about 100 A in diameter) remained adherent to the membrane surface. On the other hand, fraction 2 appeared to be made up only of a membrane structure. No 100 A particles were visible in this fraction. From these results, fraction 2 seemed to be pure membrane material.
Isolation fromPasteurella multocidaof a Lipopolysaccharide Antigen with Immunizing and Toxic Properties
Authors: Rebers Paul A. , Heddleston Kenneth L. , Rhoades Keith R.
Published: January 2020

A heat-stable, particulate, lipopolysaccharide-protein antigenic complex has been isolated from a virulent, encapsulated strain ofPasteurella multocidaby extraction with cold, formalinized saline, and centrifugation at 105,000 ×g. The original bacterial culture had been obtained from a bison that died of hemorrhagic septicemia, an infectious disease of cattle and buffalo. Injection of fractional milligram amounts of the antigen into mice, rabbits, and calves produced toxic reactions which frequently resulted in death of the host. The surviving animals demonstrated a high degree of immunity to challenge with live, virulent organisms. Two injections with 15 μg of the antigen produced a high degree of immunity in mice without the development of any signs of toxicity. The gross chemical composition and toxicity of the antigen were similar to those reported for endotoxins obtained by the Boivin or Westphal procedure. Although strong serological cross-reactions were obtained in Ouchterlony plates between the 105,000 ×gantigens from the bison strain and an avian strain with antisera to these strains, these antisera agglutinated only the bacterial cells of the homologous strain. The active immunity obtained in mice by the injection of the 105,000 ×gantigens of each strain was specific and could be correlated with the agglutination tests.
Protection ofEscherichia colifrom the Lethal Effect of Colicins by High Osmotic Pressure
Authors: Beppu Teruhiko , Arima Kei
Published: January 2020

The sensitivity ofEscherichia colito the lethal effect of colicin E2was reduced by elevation of osmotic pressure of the incubation medium. Optimal protection of the cells from the lethal effect of colicin E2was achieved with 0.6 to 0.8mNaCl or with 0.8msucrose containing 0.01mMgSO4. Under such conditions, the degradation of deoxyribonucleic acid caused by colicin E2was also suppressed markedly. It was concluded that a high concentration of sucrose with Mg++might prevent the action of the adsorbed colicin E2. A similar protection was observed against the lethal effect of colicin K.
Utilization of 5-Bromouracil by Thymineless Bacteria
Authors: Hewitt Roger , Suit Joan C. , Billen Daniel
Published: January 2020

Several thymineless
Escherichia coli
strains have been examined for their ability to replicate their deoxyribonucleic acid when bromouracil is substituted for thymine. The procedure we describe was used to identify a thymineless strain with characteristics relatively favorable to its use in bromouracil labeling experiments. In addition, mutants with an “absolute” thymine requirement could be easily distinguished from one with a “leaky” thymine requirement.
Methionine and the Regulation of Ribonucleic Acid Synthesis in
Escherichia coli
Authors: Matchett William H.
Published: January 2020

When cultures of
Escherichia coli
growing in minimal medium (M-9 salts, 0.5% glycerol, 10 μg/ml of uracil) are shifted to minimal medium supplemented with 50 μg/ml of
l
-methionine, they exhibit an abrupt increase in their relative rate of synthesis of ribonucleic acid (RNA). The rate of growth of the cells is not increased by such a shift. Sucrose density gradient analyses of cell extract after the shift showed that the effect was exerted equally on all classes of RNA. The initial relative rate of methylation of RNA, as judged by incorporation of radioactivity from
l
-methionine-methyl-
C
14
into RNA, is high in cells recovering from chloramphenicol inhibition, intermediate in cells grown in minimal medium, and low in cells grown in medium containing methionine. In cells recovering from chloramphenicol inhibition, methionine decreases the lag and increases the rate of conversion of ribonucleoprotein particles to mature 70
S
ribosomes. Turnover of RNA under these conditions, as judged by loss of C
14
-labeled methyl groups, is minimal. These results lead to the inference that methionine increases the relative rate of RNA synthesis by increasing the rate of conversion of ribonucleoprotein particles to ribosomes and thereby decreasing the availability of ribonucleoprotein particles for regulating RNA synthesis by a feedback mechanism.
Antileptospiral Activity of Serum II. Leptospiral Virulence Factor
Authors: Johnson Russell C. , Harris Virginia G.
Published: January 2020

A definite relationship exists between the resistance of leptospires to the antibody-complement system and virulence. Leptospires capable of producing either lethal or renal infections in hamsters or guinea pigs were resistant to the leptospiricidal action of antibody and complement. Avirulent leptospires, in contrast to the virulent organisms, were rapidly immobilized and killed by these serum substances. The change of a virulent culture to the avirulent state as a result of growth in culture media was accompanied by the loss of resistance to antibody and complement. Virulent leptospires were phenotypically altered when grown in the presence of the purine analogue, 8-azaguanine. The cells became sensitive to antibody and complement without a corresponding decrease in virulence. The basis for a leptospiral virulence factor, the ability to multiply in vivo, appears to reside in their capacity to resist the leptospiricidal activity of the host antibody-complement system. The immune leptospiricidal assay provides a simple and rapid method of determining the virulence of a culture.
Antigens of
Brucella abortus
I. Chemical and Immunoelectrophoretic Characterization
Authors: Hinsdill Ronald D. , Berman David T.
Published: January 2020

Extracts of
Brucella abortus
2308S, prepared either by aqueous extraction of sonically ruptured cells or by phenol-water extraction of whole cells, were subjected to various fractionation procedures and then analyzed to determine their immunoelectrophoretic patterns and chemical properties. Fraction A, prepared from sonic extracts, contained at least nine precipitable components when analyzed by immunoelectrophoresis. Of these, five components gave reactions of nonidentity with each other and, hence, represented separate antigens having unrelated determinant groups. Antigenic component IX, found in both the phenol and sonic extracts, did not form a precipitin line in the presence of serum that had been adsorbed with whole cells and was therefore tentatively identified as a “surface” antigen. From several lines of evidence, component IX was thought to be a lipopolysaccharide similar to the AP substance described by Miles and Pirie and shown by them to carry the “abortus” and “melitensis” determinant groups.