bluuebunny/crossref_metadata_2025 huggingface dataset:
Functions of F Pili in Mating-Pair Formation and Male Bacteriophage Infection Studied by Blending Spectra and Reappearance Kinetics
Authors: Novotny Charles , Raizen Eileen , Knight William S. , Brinton Charles C.
Published: January 2020

The extent of removal at various blending speeds (blending spectrum) and the kinetics of reappearance after blending of the ability of male
Escherichia coli
bacteria to form mating pairs, to adsorb and be infected by ribonucleic acid male phage, and to adsorb and be infected by deoxyribonucleic male phage were identical to the blending spectrum and reappearance kinetics of microscopically visible F pili. The same results were obtained with an Hfr (high-frequency recombinant), F′, or resistance transfer factor (RTF) fi
+
mating system. Blending did not affect the viability, growth rate, ability to adsorb T4 phage, or ability to produce new F pili at any of the speeds used. It can be concluded that microscopically visible F pili are an absolute requirement for all three functions. Three classes of F pili have been found in bacterial cultures: attached, adsorbed, and free. Bacteria with adsorbed F pili in addition to attached ones were proportionately more susceptible to male phage infection, suggesting that adsorbed F pili may be at least partially functional. Free F pili did not compete with bacteria for phage. Some implications of the virus-like nature of F-pilus outgrowth for the mechanisms of mating and male phage infection are discussed.
Location of Bacterial Polysaccharide During Various Phases of Growth
Authors: Walker P. D. , Short J.
Published: January 2020

Polysaccharide-containing material was located by histochemical staining on ultrathin sections of
Bacillus cereus
and several clostridial species during various phases of growth. These components were located along the cell wall in young vegetative cells and along the developing cortex in sporulating cells. In
B. cereus
any carbohydrate-containing material present along the forespore membrane was too small to be detected by direct staining. However, in three clostridial species such material was detected at all stages of forespore development.
Antagonistic Effect of Monovalent Cations in Maintenance of Cellular Integrity of a Marine Bacterium
Authors: De Voe Irving W. , Oginsky Evelyn L.
Published: January 2020

The susceptibility of a marine bacterium, designated isolate c-A1, to lysis in distilled water and in salt solutions has been found to be a function of Na
+
concentration. Optical densities of cells pre-exposed to 0.05
m
MgCl
2
were maintained in 1.0
m
KCl, whereas those of cells pre-exposed to 1.0
m
NaCl were not maintained at any KCl concentration tested. Cells transferred from MgCl
2
to low concentrations of NaCl underwent more extensive lysis than did those transferred to distilled water. The degree of disruption of cells transferred to distilled water from mixtures of 0.05
m
MgCl
2
and NaCl (0 to 1.0
m
) was dependent on the concentration of NaCl; similar results were obtained with LiCl, but not with KCl. In electron micrographs of thin sections, c-A1 cell envelopes consisted of two double-track layers which fractured and peeled apart on lysis after pre-exposure to NaCl-MgCl
2
mixtures. Envelope eruptions or “hernias” occurred only in lysed cells pre-exposed to NaCl alone. No evidence for a functional lytic enzyme was found. Comparative studies on a terrestrial pseudomonad with a multilayered envelope indicated that preexposure to NaCl did not enhance the susceptibility of this cell to lysis in distilled water. The lytic susceptibility of the marine bacterium is considered to be the consequence of competition between specific monovalent cations and Mg
++
for electrostatic interactions with components of the cell envelope of this organism.
Intrayeast Hyphae inParacoccidioides brasiliensis
Authors: Carbonell Luis M.
Published: January 2020

The occurrence of a live hypha inside a dead yeast during the transformation from yeast to mycelium ofParacoccidioides brasiliensisis described.
Warm-Water Strain of
Leucothrix mucor
Authors: Kelly Michael T. , Brock Thomas D.
Published: January 2020

The physiological properties and temperature responses of the first strain of
Leucothrix mucor
ever to be isolated from a warm, tropical seacoast area are described.
Recombination Between a Thermosensitive Kanamycin Resistance Factor and a Nonthermosensitive Multiple-Drug Resistance Factor
Authors: Yokota Takeshi , Kanamaru Yoshiro , Mori Reiko , Akiba Tomoichiro
Published: January 2020

The thermosensitive kanamycin (KM) resistance factor, R(KM)
t
, and a nonthermosensitive multiple-drug resistance factor, R
100
, were simultaneously introduced into
Escherichia coli
and
Salmonella typhimurium
. The temperature sensitivity of both R factors remained unchanged as long as they replicated independently. Under certain conditions, however, a new thermosensitive R factor harboring resistance markers for kanamycin, streptomycin (SM), and sulfanilamide (SA) was obtained by recombination between the R(KM)
t
and R
100
factors. R factors carrying resistance markers for KM and SA, or for SM and SA, were obtained from the recombinant R(KM SA SM)
t
by spontaneous segregation. Though the R
100
factor has been known as an fi
+
(positive for F-mediated fertility inhibition of its host) type and it does not restrict any coexisting phages, the thermosensitive recombinants of R
100
with R(KM)
t
and their segregants were found to be fi
−
and to restrict the replication of all T-even phages, as does the R(KM)
t
factor. Double infection immunity was not observed between the R(KM)
t
and R
100
factors.
Morphological and Biochemical Differentiation of Three Types of Small Oral Spirochetes
Authors: Socransky S. S. , Listgarten M. , Hubersak C. , Cotmore J. , Clark A.
Published: January 2020

Thirty strains of human oral anaerobic spirochetes were isolated in three different media: veal heart infusion-ascitic fluid, Spirolate-Brain Heart Infusion-rabbit serum, and supplemented PPLO broth. The morphological and biochemical characteristics of the isolates permitted their differentiation into three distinct species:
Treponema denticola, T. macrodentium
, and
T. oralis
(proposed new species). These species could be differentiated as follows. Organisms of the
T. denticola
type had a “2-4-2” axial fibril relationship as determined by electron microscopy, required serum for growth, did not utilize glucose or lactate, and produced indole, ammonia, acetate, and lactate as end products.
T. macrodentium
had a “1-2-1” axial fibril relationship, did not require serum, utilized glucose but not lactate, did not produce indole or ammonia, and produced formate, acetate, lactate, and succinate as acid end products.
T. oralis
had a “1-2-1” axial fibril relationship, required serum for growth, utilized lactate but not glucose, produced indole but not ammonia, and produced propionate and acetate as acid end products.
Utilization of
d
-Ribose by
Veillonella
Authors: Kafkewitz David , Delwiche E. A.
Published: January 2020

Three strains of
Veillonella
, representing two species, were unable to utilize carbohydrates as energy sources for growth. Ribose, however, was utilized biosynthetically by all three strains. Exponentially growing cultures removed
14
C-ribose from the growth medium and retained radioactivity throughout the growth cycle. The kinetics of removal of ribose from the growth medium was found to depend on the initial ribose concentration. Uptake by resting cells was found to require active metabolism, was greatly stimulated by the presence of an energy source, and was insensitive to the presence of other pentoses. Fractionation of cells showed that the ribose was used for synthesis of acid-precipitable material, with as much as 92% of the radioactivity being found in the nucleic acid fraction. The intracellular distribution of ribose radioactivity did not change during growth after uptake was completed.
Utilization of Neuraminic Acid Receptors by Mycoplasmas
Authors: Manchee Richard J. , Taylor-Robinson David
Published: January 2020

Erythrocytes and H-HeLa cells were treated with neuraminidase and then compared with untreated cells for their ability to adsorb to mycoplasma colonies or be agglutinated by suspensions of the mycoplasmas. Of the 17 mycoplasma serotypes examined, only 4 were found to use neuraminic acid receptors; these were
Mycoplasma pneumoniae, M. gallisepticum, M. synoviae
, and mycoplasma WR1. Not all strains of a serotype behaved alike. Thus, removal of receptors on erythrocytes for one strain of
M. gallisepticum
required at least 100 times the concentration of neuraminidase needed to remove them for another strain. The mechanism of attachment of erythrocytes to mycoplasma colonies does not appear to be the same as that for attachment to mycoplasmas in suspension.
α-l-Fucosidase from a Soil Bacterium
Authors: Mortensson-Egnund K. , Schöyen R. , Howe C. , Lee L. T. , Harboe A.
Published: January 2020

Intracellular glycosidases were measured in cell-free extracts obtained by ultrasonic disruption of a gram-negative soil coccobacillus (Chase, 1938). From these extracts, α-l-fucosidase was purified about 120-fold by salting out with (NH4)2SO4, ion exchange chromatography, and gel filtration. The approximate molecular weight of the enzyme was 50,000; itspH optimum was 5. The enzyme was inhibited byl-fucose and split this sugar from a purified acid mucopolysaccharide from chicken chorioallantoic fluid. The acid mucopolysaccharide is identical with a component (host antigen) of the hemagglutinin of influenza virus. Its antigenic reactivity is altered by cell-free extracts of the bacterium, in which the responsible enzyme is thought to be an α-l-fucosidase.
Immunological Responses of the Rat toMycoplasma arthritidis
Authors: Cole B. C. , Cahill J. F. , Wiley B. B. , Ward J. R.
Published: January 2020

Arthritis was produced in rats by the intravenous injection ofMycoplasma arthritidis. Metabolic inhibiting antibody and indirect hemagglutinating antibody could not be detected in the sera of arthritic or convalescent animals. Nonmurine species of mycoplasma were capable of inducing metabolic inhibiting antibody in the rat. A hypothesis based upon the possible occurrence of heterogenetic antigens common toM. arthritidisand rat tissue was brought forward to explain these findings. Complement-fixing antibody toM. arthritidiswas detected 3 to 4 days after injection and subsequently rose to high levels, depending upon the severity of arthritis and number of organisms injected. Animals that had recovered from intravenous or subcutaneous inoculation withM. arthritidiswere resistant to subsequent infections by the organism. Immunity could be passively transferred by the intravenous injection of convalescent serum. Adsorption of the convalescent serum with antigen greatly reduced the complement fixation titer but did not significantly alter the protective properties of the serum. The presence of complement-fixing antibody could not be related to the development of immunity. An avirulent strain ofM. arthritidisand a strain previously classified asM. hoministype 2 were capable of inducing resistance to subsequent injection by virulentM. arthritidis.
Vital Staining of
Mycoplasma
and L-Forms with Chlorazol Black E
Authors: Berliner Martha D. , Kundsin Ruth B. , Allred Elizabeth N.
Published: January 2020

Vital staining of
Mycoplasma
colonies was attempted because other dye visualization techniques kill the organisms and preclude reisolation for further studies. The lipophilic amphoteric dye Chlorazol Black E (CBE) was the most successful of 14 vital dyes tested on
Mycoplasma hominis, M. pharyngis, M. fermentans, M. arthritidis, M. salivarium, M. pneumoniae
, and L-forms of
Staphylococcus aureus
when used in 1:1,000 (w/v) saline dilution as the sterile suspension medium for inoculation of Hayflick's medium under both aerobic and microaerophilic (Fortner method) conditions. Colonies of all species stain homogeneously in the periphery and center portion, the latter being more refractive under positive phase contrast. All stained colonies were successfully subcultured. The most striking and promising result of the use of CBE as a tool for physiological study of
Mycoplasma
was a very significant increase in diameter of all colonies except those of
M. pneumoniae
grown with CBE: 1.5 × for
M. hominis
and 5 × for L-form
S. aureus
. This size increase in
M. hominis
is proportional to the concentration down to a 1:50,000 dilution only under microaerophilic conditions. Whether this increase in colony size is due to an increased number of cells, to larger cells, or to the adsorption of CBE on the lipid membrane is unknown at present.
Uncoupling of Protein and Ribonucleic Acid Synthesis by 5′,5′,5′-Trifluoroleucine in
Salmonella typhimurium
Authors: Trela John M. , Freundlich Martin
Published: January 2020

The addition of 5′,5′,5′-trifluoroleucine (fluoroleucine) to leucine auxotrophs of
Salmonella typhimurium
permitted protein but not ribonucleic acid (RNA) synthesis to continue after leucine depletion. The uncoupling of the formation of these macromolecules by fluoroleucine was apparent if RNA and protein synthesis was measured either by the uptake of radioactive precursors or by direct chemical determinations. The analogue did not appear to be an inhibitor of RNA formation, since it was as effective as leucine in permitting RNA synthesis in a leucine auxotroph upon the addition of small amounts of chloramphenicol. In contrast to these data, fluoroleucine allowed continued protein and RNA formation in a leucine auxotroph of
Escherichia coli
strain W. In addition, contrary to the results obtained with
S. typhimurium
, the analogue replaced leucine for repression of the leucine bio-synthetic enzymes as well as the isoleucine-valine enzymes. We propose that these ambivalent effects of fluoroleucine on repression and RNA and protein synthesis in the two strains are due to differences in the ability of the analogue to attach to the various species of leucine transfer RNA.
Permeability Properties of
Aspergillus nidulans
Protoplasts
Authors: Elorza M. Victoria , Arst Herbert N. , Cove David J. , Scazzocchio Claudio
Published: January 2020

The regeneration of mycelial forms from protoplasts of mutant and wild-type strains of
Aspergillus nidulans
was followed microscopically under conditions with which the rate of regeneration depends upon a specific transport function. This method has shown that at least four uptake systems—one for divalent anions, two for purines, and one for sugars—remain functional after removal of the cell wall.
Synthesis of Bacterial Flagella II. PBSl Transduction of Flagella-specific Markers in
Bacillus subtilis
Authors: Grant Geoffrey F. , Simon Melvin I.
Published: January 2020

The linkage relationship of mutants involved in the synthesis of flagella was determined by PBSl transduction. Mutants that affect the structure of flagellin (
hag
) and temperature-sensitive mutants (
flaTS
) that produce flagella when grown at 37 C but not when grown at 46 C were examined. All of the mutants were found to be linked to the
hisA1
marker. The
flaTS
mutants fell into three clusters. Group A contained the majority of mutants which were loosely grouped around the
hag
locus. Group B mutants were segregated from the
hag
locus and appeared closely linked to the phage adsorption site gene (
gtaA
), and group C was only loosely linked to
hisA1
and thus far contains only one mutant. A flagella locus (
ifm
) affecting both the degree of motility and level of flagellation was shown to map near group A. Mutants affecting motility (
mot
) were not linked to
hisA1
by PBSl transduction. Several markers previously shown to link to
hisA1
were ordered with respect to
hisA1
and the flagellar genes.
Immunological Response of the Rabbit to Vi Antigen
Authors: Esposito Vito M. , Feeley John C. , Leeder Wayne D.
Published: January 2020

Vi antibody response of rabbits varied depending on whether Vi antigen was administered in particulate or soluble state. Vi antigen in particulate form induced hemagglutinins, bacterial agglutinins, and passive cutaneous anaphylaxis (PCA) antibodies, whereas soluble Vi antigen induced only hemagglutinins. Guinea pigs passively sensitized with antisera against particulate Vi antigen gave PCA reactions when challenged with either soluble or cellular Vi antigen; antisera against soluble Vi antigen were negative for PCA. The specificity of PCA was demonstrated by its dependence on the Vi concentration and by absorption of PCA activity from antisera with V-form cells ofSalmonella typhosa.
Antigenic Structure ofTreponema pallidum, Nichols Strain II. Extraction of a Polysaccharide Antigen with “Strain-specific” Serological Activity
Authors: Miller James N. , Bekker J. H. , DeBruijn J. H. , Onvlee P. C.
Published: January 2020

An ultracentrifugally homogeneous heat-stable polysaccharide preparation free from serologically reactive rabbit testicular tissue antigen, including cardiolipin, was extracted from the Nichols strain ofTreponema pallidum, and found to react by complement-fixation with homologous rabbit sera but not with human syphilitic sera. In addition, the reactive “strain-specific” component was found to be distinct from a second reactive component within the preparation related to an antigen ofT. reiteri.
Interaction of
Bdellovibrio bacteriovorus
and Host Bacteria II. Intracellular Growth and Development of
Bdellovibrio bacteriovorus
in Liquid Cultures
Authors: Varon Mazal , Shilo M.
Published: January 2020

The intracellular life cycle of
Bdellovibrio bacteriovorus
109 growing on
Escherichia coli
in a dilute nutrient medium exhibits a period of constant infective titer while the parasite grows and elongates inside the host cell. This period is terminated after 2 to 4 hr, and the number of the plaque-forming units in the culture rises rapidly to as much as six times the initial titer. The growth pattern of
Bdellovibrio
is similar with actively growing or resting host cells, or with host cells killed by ultraviolet irradiation or by heating at 70 C. The yield of
B. bacteriovorus
strain 109 in two-membered cultures with
E. coli
B depends on the host concentration and may reach 7.5 × 10
10
cells per ml. Penicillin, which has no effect on the attachment and penetration of
Bdellovibrio
, inhibits its multiplication.
Phospholipid Metabolism in
Ferrobacillus ferrooxidans
Authors: Short Steven A. , White David C. , Aleem M. I. H.
Published: January 2020

The lipid composition of the chemoautotroph
Ferrobacillus ferrooxidans
has been examined. Fatty acids represent 2% of the dry weight of the cells and 86% of the total are extractable with organic solvents. About 25% of the total fatty acids are associated with diacyl phospholipids. Polar carotenoids, the benzoquinone coenzyme Q-8, and most of the fatty acids are present in the neutral lipids. The phospholipids have been identified as phosphatidyl monomethylethanolamine (42%), phosphatidyl glycerol (23%), phosphatidyl ethanolamine (20%), cardiolipin (13%), phosphatidyl choline (1.5%), and phosphatidyl dimethylethanolamine (1%) by chromatography of the diacyl lipids, by chromatography in four systems of the glycerol phosphate esters derived from the lipids by mild alkaline methanolysis, and by chromatographic identification of the products of acid hydrolysis of the esters. No trace of phosphatidylserine (PS), glycerolphosphorylserine, or serine could be detected in the lipid extract or in derivatives of that extract. This casts some doubt on the postulated involvement of PS in iron metabolism. After growth in the presence of
14
C and
32
P, there was essentially no difference in the turnover of either isotope in the glycerolphosphate ester derived from each lipid in cells grown at
p
H 1.5 or 3.5.
Mode of Action of Streptolydigin
Authors: Siddhikol Chalongkwan , Erbstoeszer John W. , Weisblum Bernard
Published: January 2020

Streptolydigin and rifamycin inhibit the catalytic function of ribonucleic acid (RNA) polymerase. Streptolydigin can inhibit polymerization after the reaction has started, whereas rifamycin is effective only if it is preincubated with RNA polymerase prior to the addition of substrates. The same relationships are observed with respect to these two antibiotics if the nucleoside triphosphate-pyrophosphate exchange reaction is used in the assay system. The inhibitory effect of streptolydigin is reversible by further addition of RNA polymerase but not by addition of deoxyribonucleic acid to the assay system.
Ammonium Sulfate Coprecipitation Antibody Determination with Purified Staphylococcal Enterotoxins
Authors: Gruber Jack , Wright George G.
Published: January 2020

The ammonium sulfate coprecipitation technique of Farr was applied in a study of the purified enterotoxins ofStaphylococcus aureus. Ammonium sulfate coprecipitation of iodine-131-labeled enterotoxins A, B, and C, with the use of a 1.6mconcentration of (NH4)2SO4, revealed differences in the antigen-binding capacity of normal and immune rabbit sera for the enterotoxins. The coprecipitation technique provided a quantitative test for detecting antibody to enterotoxin that was more sensitive than agar-gel diffusion methods. Antigen-binding tests suggested the presence of similar antigenic determinant groups in all three toxins. Measurable antigenbinding capacities for enterotoxins A, B, and C were detected in sera of normal human subjects and became elevated in several subjects accidently exposed to enterotoxin.
Divergent Metabolic Pathways for Propane and Propionate Utilization by a Soil Isolate
Authors: Vestal J. R. , Perry Jerome J.
Published: January 2020

The metabolism of propane and propionate by a soil isolate (Brevibacteriumsp. strain JOB5) was investigated. The presence of isocitrate lyase in cells grown on isopropanol, acetate, or propane and the absence of this inducible enzyme inn-propanol- and propionate-grown cells suggested that propane is not metabolized via C-terminal oxidation. Methylmalonyl coenzyme A mutase and malate synthase are constitutive in this organism. The incorporation of14CO2into pyruvate accumulated during propionate utilization suggests that propionate is metabolized via the methyl-malonyl-succinate pathway. These results were further substantiated by radiorespirometric studies with propionate-1-14C, -2-14C, and -3-14Cas substrate. Propane -2-14Cwas shown, by unlabeled competitor experiments, to be oxidized to acetone; acetone and isopropanol are oxidized in this organism to acetol. Cleavage of acetol to acetate and CO2would yield the inducer for the isocitrate lyase present in propane-grown cells.
Organization of Enzymes in the Common Aromatic Synthetic Pathway: Evidence for Aggregation in Fungi
Authors: Ahmed S. I. , Giles Norman H.
Published: January 2020

Centrifugation in sucrose density gradients of partially purified extracts from six species of fungi, i.e.,
Rhizopus stolonifer, Phycomyces nitens, Absidia glauca
(
Phycomycetes
),
Aspergillus nidulans
(
Ascomycetes
),
Coprinus lagopus
, and
Ustilago maydis
(
Basidiomycetes
), indicate that the five enzymes catalyzing steps two to six in the prechorismic acid part of the polyaromatic synthetic pathway sediment together. The sedimentation coefficients for these enzymes are very similar in the six species and are comparable to those previously observed for the multienzyme complexes (
arom
aggregates) of
Neurospora crassa
and
Saccharomyces cerevisiae
. These results are interpreted as indicating the presence in each of these fungi of
arom
aggregates, presumably encoded by
arom
gene clusters similar to those in
N. crassa
and
S. cerevisiae
. Evidence has also been obtained for the presence in two species (
A. nidulans
and
U. maydis
) and the absence in the other four species of a second dehydroquinase isozyme which is distinguishable from the synthetic activity on the basis of both thermostability tests and
S
values. This second dehydroquinase, which is apparently involved in the catabolism of quinic acid via a pathway similar to that in
N. crassa
, is inducible in
A. nidulans
(as it is in
N. crassa
), but constitutive in
U. maydis
. These comparative findings are discussed in relation to the organization, evolution, and possible functional relationships of synthetic and catabolic aromatic pathways in fungi.
Base Sequence Homology and Renaturation Studies of the Deoxyribonucleic Acid of Extremely Halophilic Bacteria
Authors: Moore Richard L. , McCarthy Brian J.
Published: January 2020

The genetic relatedness among various strains of halophilic bacteria has been assessed by deoxyribonucleic acid-deoxyribonucleic acid (DNA-DNA) duplex formation and ribosomal ribonucleic acid (RNA) hybridization. All of the strains of extremely halophilic rods are closely related, and the extent of divergence of base sequence is similar for the major and minor DNA components. Parallel experiments with ribosomal RNA revealed a relationship between the extremely halophilic rods and cocci and a more distant relationship to moderate halophiles and to a photosynthetic extreme halophile. Renaturation studies of halophile DNA exclude the possibility that the satellite DNA represents multiple copies of a small episomal element. The kinetics of DNA renaturation show that the genome size of the extreme and moderate halophiles is similar to that of
Escherichia coli
.
Transduction of Merodiploidy: Induced Duplication of Recipient Genes
Authors: Hill C. W. , Schiffer Dinah , Berg Paul
Published: January 2020

Escherichia coli
PB160, which carries a tandem duplication with the gene order
metB
+
argH
−
su
159
+
thi
+
:
metB
+
argH
+
su
159
−
thi
+
, was used to study the mechanism of P1 transduction of genes in the duplicated region. Transduction of the
su
159
+
allele contained within the duplicated segment yields two kinds of
su
159
+
recombinants: 91% are haploid
su
159
+
and 9% are
su
159
+
/
su
159
−
merodiploids. The duplication in these merodiploid transductants includes the
metB
locus; however, both copies of the
metB
locus usually are derived from the recipient. Thus, the requirements for transduction of the “condition of merodiploidy” appear to be the cotransduction of the repeat point (the region where the duplication begins to repeat itself) and, of course, the selected marker (in this case
su
159
+
). A mechanism whereby two recipient chromosomes interact with the transduced “repeat point” region to regenerate the tandem duplication is implicated. It appears that a duplication much larger than the quantity of genetic material carried by a P1 phage can be produced in a transductant.
Temperature-sensitive Repression of the Tryptophan Operon in
Escherichia coli
Authors: Ito Koreaki , Hiraga Sota , Yura Takashi
Published: January 2020

Mutants of
Escherichia coli
exhibiting temperature-sensitive repression of the tryptophan operon have been isolated among the revertants of a tryptophan auxotroph,
trpS5
, that produces an altered tryptophanyl transfer ribonucleic acid (tRNA) synthetase. Unlike the parental strain, these mutants grew in the absence of tryptophan at high but not at low temperature. When grown at 43.5 C with excess tryptophan (repression conditions), they produced 10 times more anthranilate synthetase than when grown at 36 C or lower temperatures. Similar, though less striking, temperature-sensitivity was observed with respect to the formation of tryptophan synthetase. Transduction mapping by phage P1 revealed that these mutants carry a mutation cotransducible with
thr
at 60 to 80%, in addition to
trpS5
, and that the former mutation is primarily responsible for the temperature-sensitive repression. These results suggest that the present mutants represent a novel type of mutation of the classical regulatory gene
trpR
, which probably determines the structure of a protein involved in repression of the tryptophan operon. In agreement with this conclusion, tRNA of several
trpR
mutants was found to be normal with respect to its tryptophan acceptability. It was also shown that the
trpS5
allele, whether present in
trpR
or
trpR
+
strains, produced appreciably higher amounts of anthranilate synthetase than the corresponding
trpS
+
strains under repression conditions. This was particularly true at higher temperatures. These results provide further evidence for our previous conclusion that tryptophanyl-tRNA synthetase is somehow involved in repression of this operon.
Electron Microscopic Study of a Slime Layer
Authors: Jones H. C. , Roth I. L. , Sanders W. M.
Published: January 2020

Slime layers are being studied in our laboratories in an attempt to understand their functions in the control of pollution in natural streams. A method for fixing, staining, and embedding microorganisms in the intact slime has been developed. In this method, epoxy resin discs are placed in a holder and are introduced into a simulated stream. After various periods of time the discs are punched out of the holder into the fixative. The disc with the attached slime is fixed, stained (4% osmium tetroxide plus ruthenium red), dehydrated, and embedded in epoxy resin so that thin sections can be cut through the vertical plane of the slime mass. Such thin sections permit detailed examination of the attached layer, the surface-slime interface, the spatial relationships between cells in the vertical slime structure, and the strands of extracellular material between and around cells. No special attachment structures were noted as the cells appeared to be attached to the surface by extracellular material alone. This material was observed in strands and netlike forms between cells which are positioned 1 to 4 μm apart in the slime.
New Method for the Detection of a Lethal Factor in Vibrios
Authors: Takeya Kenji , Shimodori Shoichi
Published: January 2020

When vibriocinogenic vibrios were mixed with an indicator strain, “lacunas” (plaquelike clearings) were observed, thus providing a new method for detection of vibriocins.
Infection of
Bacillus stearothermophilus
with Bacteriophage Deoxyribonucleic Acid
Authors: Streips Uldis N. , Welker N. E.
Published: January 2020

Early stationary-phase cells are most susceptible to infection with deoxyribonucleic acid from bacteriophage TP-1C. Transfection is destroyed by deoxyribonuclease and unaffected by phage antiserum.
Clustering of Functionally Related Genes in
Pseudomonas aeruginosa
Authors: Rosenberg S. L. , Hegeman G. D.
Published: January 2020

Genes for the mandelate and benzoate pathways in
Pseudomonas aeruginosa
are clustered to a greater degree than that predicted on the basis of the induction pattern.
Factors Affecting Immunogenic Activity of Mycobacterial Ribosomal and Ribonucleic Acid Preparations
Authors: Youmans Anne S. , Youmans Guy P.
Published: January 2020

By following careful procedures, mycobacterial ribosomal fractions and ribonucleic acid (RNA) prepared by ethyl alcohol precipitation were obtained which have immunogenic activities similar to the viable attenuated H37Ra cells ofMycobacterium tuberculosisfrom which they were obtained. This comparison was based on the amount of ribonucleic acid (RNA) present. These preparations consisted of approximately 63% RNA and 37% protein; no deoxyribonucleic acid or polysaccharide was detected by chemical tests. A high correlation was found between the immunogenic activity of a preparation and the per cent increase in hyperchromicity at 260 nm of a ribonuclease-hydrolyzed portion. Final concentrations of sodium dodecyl sulfate higher than 0.25% when used for the preparation of the ribosomal fractions and RNA resulted in significantly lower immune responses and greater variation between experiments. This was not related to the amount of protein present. The stability of the ribosomal and RNA preparations was tested under a variety of conditions. The need for a good protective adjuvant again was shown since mouse serum readily hydrolyzed the RNA. Equal immunity was obtained after immunization by the intraperitoneal and subcutaneous routes; however, no immune response was obtained when the intravenous route was used. Preliminary results with RNA prepared with phenol showed that it was more easily degraded during preparation. This resulted in a lower immune response than was obtained with the RNA prepared with ethyl alcohol.
Histamine-sensitizing Factor, Mouse-protective Antigens, and Other Antigens of Some Members of the GenusBordetella
Authors: Ross R. , Munoz J. , Cameron C.
Published: January 2020

The three species of the genusBordetella—B. pertussis, B. parapertussis, andB. bronchiseptica—have many antigens in common. Studies on representative strains of these species have shown that there are only a few specific antigens in each species. Whole-cell vaccines and extracts fromB. pertussiscontained specific mouse-protective antigen and a histamine-sensitizing factor. In addition, whole-cell vaccines and some saline extracts protected mice against intracranial challenge withB. bronchiseptica. Cells and a saline extract ofB. parapertussisalso protected againstB. bronchisepticabut not againstB. pertussis. Whole cells ofB. bronchisepticaprotected againstB. bronchiseptica, but only one of three saline extracts protected against this challenge. Neither whole cells nor saline extracts fromB. bronchisepticaprotected againstB. pertussis. The antigen inB. pertussisresponsible for cross-protection againstB. bronchisepticawas less resistant to heat than the protective antigen inB. bronchiseptica. Since histamine-sensitizing factor was not detected inB. bronchisepticaorB. parapertussiscells or extracts, this factor is not required to protect mice againstB. bronchisepticachallenge. WhetherB. pertussisvaccines protected againstB. bronchisepticaby a nonspecific mechanism was not established, but it is clear that the specific antigen responsible for protection againstB. pertussiswas found only inB. pertussisand not inB. bronchisepticaorB. parapertussis.
Fatty Acids in the Lipids of Marine and Terrestrial Nitrifying Bacteria
Authors: Blumer M. , Chase T. , Watson S. W.
Published: January 2020

Fatty acids in the lipids of 19 marine and terrestrial nitrifying bacteria have been analyzed. Ammonia-oxidizing bacteria have a very simple acid composition; palmitic and palmitoleic acid account for 96 to 100% of the total acids. The fatty acids of nitrite-oxidizing bacteria cover a wider range, from C
14
to C
19
, but from two to four acids still account for more than 80% of the total acids. Branched iso- and anteiso-acids are present in traces only in 2 of the 19 bacteria. The chemical and morphological similarity between blue-green algae and these bacteria is discussed.
Amino Acid Differences in a 30
S
Ribosomal Protein from Two Strains of
Escherichia coli
Authors: Sypherd Paul S.
Published: January 2020

The 30
S
ribosomal proteins of the K-12 and B strains of
Escherichia coli
differ in at least one protein component. This component, which is allelic in the two strains, has been isolated from both organisms. Amino acid analyses show that the protein from strain B contains between 20 and 28 more amino acids than does the analogue protein from strain K-12.
Enzymatic Phosphorylation of Streptomycin by Extracts of Streptomycin-producing Strains of
Streptomyces
Authors: Miller Ann L. , Walker James B.
Published: January 2020

Extracts of post-exponential phase mycelia of
Streptomyces bikiniensis
ATCC 11062, and other streptomycin-producers, catalyze phosphorylation of streptomycin and dihydrostreptomycin with adenosine-5′-triphosphate. The phosphate is esterified with an —OH group of the streptidine moiety. It is suggested that
O
-phosphoryl-streptomycin might serve as an intracellular precursor of extracellular streptomycin or as a detoxification product of streptomycin or that it might serve an unknown physiological function in the producing organism.
Prototrophic Thermophilic Bacillus: Isolation, Properties, and Kinetics of Growth
Authors: Epstein Israel , Grossowicz Nathan
Published: January 2020

A thermophilic bacillus (minimal growth temperature 41 C, optimal 55 to 58 C, and maximal 65 C) was isolated from a manure pile. It is very similar to
Bacillus stearothermophilus
, but it differs in its inability to hydrolyze starch. The thermophilic isolate is a prototroph which grows in a minimal medium consisting of glucose, ammonium salt, phosphate buffer, and inorganic salts. At all temperatures studied (low to high), the same minimal nutritional requirements prevailed. The Arrhenius constant for growth was found to be 15,000 and 13,500 cal/mole in the minimal and rich media, respectively.
Taxonomic Investigations on Expressed and Cryptic Phospho-β-glucosidases in
Enterobacteriaceae
Authors: Schaefler S. , Malamy A.
Published: January 2020

In the
Enterobacteriaceae
, β-glucosides are catabolized by a complex system formed of three permeases, with partly overlapping substrate specificities, and two hydrolytic enzymes, phospho-β-glucosidase A and B, which hydrolyze only phosphorylated β-glucosides. Some
Enterobacteriaceae
such as
Klebsiella-Aerobacter
(
Enterobacter
) possess the complete system; others possess only parts of it or may have a cryptic phospho-β-glucosidase activity without permease activity. A screening test applied to strains belonging to several genera of
Enterobacteriaceae
showed that strains of
Citrobacter, Hafnia
, and
Serratia
exhibit a degree of similarity in phospho-β-glucosidase activity and inducibility which could be useful in their taxonomic characterization; others, such as
Aerobacter aerogenes, Erwinia
, and
Proteus vulgaris
, are more heterologous. Owing to the presence of inducible phospho-β-glucosidases A and B in
Citrobacter
, the fermentation of β-methyl glucoside and the fermentation of arbutin in mixture with cellobiose could be of diagnostic value in the differentiation of
Citrobacter
from
Salmonella
. Wild-type strains of
Escherichia coli, Shigella
, and
Salmonella
are phenotypically similar in their inability to catabolize β-glucosides, the presence of constitutive P-β-glucosidase A, and the lack of β-glucoside permeases I and II. Their β-glucoside-fermenting mutants show, however, a phospho-β-glucosidase and β-glucoside permease activity which is characteristic for mutants from each genus. The differences in the phenotype of the mutants reflect probable differences in the presence of cryptic genes in the wild-type strains and could be of evolutionary significance.
Role of Ammonium Ion in the Biosynthesis of β-Nitropropionic Acid
Authors: Shaw Paul D. , DeAngelo Anthony B.
Published: January 2020

The metabolism of inorganic nitrogen compounds was studied in extracts ofPenicillium atrovenetumwhich had been grown under conditions in which β-nitropropionic acid (BNP) synthesis varied from 0 to 12.5 μmoles per ml. None of the extracts was able to oxidize ammonium ion or nitrite. An enzyme was detected which catalyzed the oxidation of hydroxylamine with cytochromecas the electron acceptor. The activity of this enzyme was not related to the ability of the organism to produce BNP. Nitrate and nitrite reductase activities were detected only inP. atrovenetumcultures grown on nitrate as a nitrogen source. These results indicated that BNP synthesis is probably not directly associated with the metabolism of inorganic nitrogen compounds and that an organic pathway for the formation of the nitro group is more likely. The activities of certain enzymes related to the metabolism of aspartic acid were investigated. Aspartate ammonia-lyase activity could not be detected inP. atrovenetumextracts. Aspartate aminotransferase and glutamate dehydrogenase activities were found in the extracts but were highest in the cultures which did not produce BNP. β-Nitroacrylic acid reductase activity was highest in extracts of cultures which were actively synthesizing BNP.
Evidence for a Multiplicity of Capsular Types Among
Staphylococcus aureus
Strains
Authors: Maverakis Nick H. , Wiley Bill B.
Published: January 2020

The Smith diffuse variant and the wound mucoid strain of
Staphylococcus aureus
were shown to exhibit serologically distinct capsules. The Welwood and K-6 strains of
S. aureus
were tested to determine their capsular types. Both Welwood and K-6 were found to be representative of the Smith capsular type. An additional 13 isolates of
S. aureus
from mice were tested. Gel double-diffusion tests and immunoelectrophoresis of staphylococcal antigens disclosed the possible existence of at least two additional capsular types. Passive hemagglutination tests carried out with cells sensitized with 1 mg of antigen per ml showed a multiplicity of cross-reacting antigens. However, cells sensitized either with 0.1 or 0.05 mg of antigen per ml and reacted with antisera absorbed with 10 or 1 μg/ml showed the presence of a specific antigen in each strain of
S. aureus
. Corroborative evidence for a multiplicity of capsular types was obtained by the specific capsular reaction. At least four capsular types of
S. aureus
were found. The prototypic strains for these antigens are the RLM or wound strain, the Smith diffuse strain, and mouse strains designated 36T and 43R. We propose to designate these types 1, 2, 3, and 4, respectively.
R Factor Transmission In Vivo
Authors: Jarolmen H. , Kemp G.
Published: January 2020

Experimental infections were induced in weanling pigs orally both with nalidixic acid (NA)-sensitive and -resistant strains of
Salmonella choleraesuis
var.
kunzendorf
, designated RC221 and RC221NA, respectively. Prior to the time of infection, cultures of normal bacterial flora were isolated from swine fecal matter and screened for the presence of R factors. A majority of these bacterial isolates harbored transferable resistances. Both strains RC221 and RC221NA have been shown to be competent recipients in vitro of the R factors present in the normal intestinal flora. The property of NA resistance greatly facilitated recovery of the infecting organism. After infection, salmonellae from liver, lung, spleen, lymph node, intestine, and feces were screened for the presence of R factors. Transfer of drug resistance in vivo was a rare occurrence; however, if infected specimens, particularly intestinal, were incubated in nutrient broth prior to plating, R factor transfer occurred, presumably in the test tube. Changes in recipient cultures were frequently observed after introduction of R factors from organisms of pig origin into the
S. choleraesuis
var.
kunzendorf
test organisms. Alterations include changes in typing reaction, granular growth in broth, differences in colony form, and reduction of virulence.
Identification of Adenosine-3′,5′-Monophosphate as the Bacterial Attractant for Myxamoebae of
Dictyostelium discoideum
Authors: Konijn T. M. , van de Meene J. G. C. , Chang Y. Y. , Barkley D. S. , Bonner J. T.
Published: January 2020

Adenosine-3′,5′-cyclic monophosphate was shown to be the compound found in
Escherichia coli
responsible for the attraction of the amoebae of the cellular slime mold
Dictyostelium discoideum
. A number of other nucleotides were tested and the following were active: tubercidin-3′,5′-cyclic monophosphate, N
6
-2′-
O
-dibutyryl-adenosine-3′,5′-cyclic monophosphate, 5′-methylene adenosine-3′,5′-cyclic monophosphonate, guanosine-3′,5′-cyclic monophosphate, uridine-3′,5′-cyclic monophosphate, cytidine-3′,5′-cyclic monophosphate, inosine-3′,5′-cyclic monophosphate, and thymidine-3′,5′-cyclic monophosphate. They were less active than adenosine-3′,5′-cyclic monophosphate. It is suggested that cyclic adenosine monophosphate secreted by the bacteria is used by the amoebae as a means of sensing and orienting towards food.
Estimation and Identification of
Streptococcus dysgalactiae
Protective Antibody in Sera of Rabbits and Cattle
Authors: Stark D. M. , Norcross N. L. , Leahey J. E.
Published: January 2020

Rabbit and cow anti-
Streptococcus dysgalactiae
sera were tested by bacterial agglutination, complement fixation, hemagglutination, and immunodiffusion for the presence of antibody. The results of these tests were compared with mouse-protection studies on the same serum to estimate which in vitro test would best reflect the in vivo protective capacity of serum. Identification of the antibody constituents responsible for the mouse protection, hemagglutination, and complement fixation titers were established by reacting whole and diluted antisera with mercaptoethanol before and after testing. Results indicate that the complement fixation test may be a more accurate indicator of IgG protective bovine and rabbit antibody, whereas the hemagglutination test may more readily reflect a wider range of protective antibody levels and IgM. The complement fixation test showed some shared responses to IgG and IgM in both the rabbit and cow, whereas the IgM components seemed to be the predominant factor influencing hemagglutination titers in the rabbit and more so in the bovine. Mouse protection tests with mercaptoethanol-treated cow and rabbit sera indicate that the protective capacity of these antisera is shared between IgM and IgG components.
Transcriptional Mapping: Functional Organization of the Ribosomal and Transfer Ribonucleic Acid Cistrons in the
Bacillus subtilis
Genome
Authors: Bleyman Michael , Kondo Masatoshi , Hecht Norman , Woese Carl
Published: January 2020

The transcriptional mapping method developed previously has been used to investigate the functional organization of the ribosomal ribonucleic acid (rRNA) and transfer ribonucleic acid (tRNA) cistrons in the
Bacillus subtilis
genome. The sensitivities of the syntheses of these RNA species to actinomycin D indicated that (i) large polycistronic groupings of the tRNA cistrons exist, but (ii) the 16
S
and 23
S
rRNA cistrons are probably transcribed as individual units, and (iii) each 5
S
rRNA cistron is part of an operon containing a 23
S
rRNA cistron.
Dissimilation of Methionine by Fungi
Authors: Ruiz-Herrera José , Starkey Robert L.
Published: January 2020

Soil fungi that attacked methionine required a utilizable source of energy such as glucose for growth. This is an example of co-dissimilation. Experiments with one of the fungi, representative of the group, are reported. In the absence of glucose, pregrown mycelium, even when depleted of energy reserves, oxidatively deaminated methionine with accumulation of α-keto-γ-methyl mercapto butyric acid and α-hydroxy-γ-methyl mercapto butyric acid. When glucose was provided, all of the sulfur of methionine was released as methanethiol, part of which was oxidized to dimethyl disulfide. No sulfate, sulfide, or hydrosulfide products were detected. Evidence was obtained that deaminase and demethiolase were constitutive. Deamination preceded demethiolation and α-keto butyric acid accumulated as a product of the two reactions. Other carbon residues were α-hydroxy butyric acid and α-amino butyric acid. Inability of the fungus to metabolize α-keto butyrate was responsible for its inability to utilize methionine as a source of carbon and energy. Several other fungi isolated from soil grew on α-amino butyrate but could not grow on methionine owing to inability to demethiolate it.
Kinetic Studies of Iron Oxidation by Whole Cells of
Ferrobacillus ferrooxidans
Authors: Schnaitman C. A. , Korczynski M. S. , Lundgren D. G.
Published: January 2020

A colorimetric assay was developed for studying the kinetics of iron oxidation with whole cells of the chemoautotroph,
Ferrobacillus ferrooxidans
. The assay was more advantageous than the conventional method of Warburg manometry because of its simplicity, rapidity, and the small amount of cells required. The assay measured Fe
3+
as a chloride complex which absorbs at 410 nm. Kinetic analysis showed the apparent
K
m
for iron oxidation to be 5.4 × 10
−3
m
in an unbuffered system and 2.2 × 10
−3
m
in the presence of β-alanine-SO
4
2−
buffer. Glycine and β-alanine buffers were used in the measurement of the
p
H optimum for iron oxidation; the optimum ranged from 2.5 to 3.8. The effect of
p
H was primarily on the
V
max
while the
K
m
remained constant. Added SO
4
2−
was found to stimulate iron oxidation by increasing the
V
max
of iron oxidation by whole cells, but it did not affect the
K
m
. Results of assays of iron oxidation in systems containing various mole percentages of SO
4
2−
and Cl
−
indicated that Cl
−
did not inhibit iron oxidation but that SO
4
2−
was required. Sulfate could be partially replaced by HPO
4
2−
and HAsO
4
2−
but not by BO
3
−
, MoO
4
2−
, NO
3
−
, or Cl
−
; formate and MoO
4
2−
inhibited iron oxidation.