bluuebunny/crossref_metadata_2025 huggingface dataset:
Nucleic Acid Similarities Among
Pseudomonas pseudomallei, Pseudomonas multivorans
, and
Actinobacillus mallei
Authors: Rogul M. , Brendle J. J. , Haapala D. K. , Alexander A. D.
Published: January 2020

Annealing experiments on membrane filters were carried out with deoxyribonucleic acids (DNA) from selected strains of the nomen-species of
Pseudomonas, Actinobacillus, Chromobacterium
, and
Micrococcus
, with the use of DNA of
Pseudomonas pseudomallei
and
Actinobacillus mallei
as reference materials. Under the usual conditions employed in these experiments, the results were not quantitatively reproducible. Incorporation of dimethylsulfoxide (DMSO) into the incubation medium greatly increased differences in comparative binding. DNA binding in agar matrices was examined in the presence and absence of DMSO at various incubation temperatures. It was found that the greatest specificity, stability, and total binding for DNA containing high amounts of guanine and cytosine occurred in the presence of DMSO. Under the most stringent annealing conditions permitted in agar, DNA species from
P. pseudomallei
and
A. mallei
in the presence of DMSO demonstrated interspecific relative bindings of 76 to 86% when compared to the homologous reactions. The thermal elution midpoints (E
m
) of these duplexed interspecific DNA species were quite close to the homologous E
m
values. The relative bindings of
P. multivorans
DNA types to either reference DNA ranged between 6 to 27%, and the E
m
values were 4 to 7 C less than those for the homologous reactions.
Quantitive Autoradiographic Study of Competence and Deoxyribonucleic Acid Incorporation in
Bacillus subtilis
Authors: Somma Sergio , Polsinelli Mario
Published: January 2020

The relationships among deoxyribonucleic acid (DNA) uptake, transformation, and autoradiographic labeling were investigated. It is shown that: (i) autoradiography is a good method for measuring the total fraction of competent cells able to incorporate transforming DNA; in our best experiment that fraction was 11.5%. (ii) Computation of the fraction of competent cells in a culture of
Bacillus subtilis
, by comparing the frequencies of single and double transformants for two unlinked markers, gives values which are somewhat different from those obtained by auto-radiography. (iii) On the average, a competent cell of
B. subtilis
irreversibly takes up from 0.9 × 10
−10
to 1.4 × 10
−10
μg of DNA; this amount represents about 1/55 to 1/35 of the bacterial chromosome weighing 5 × 10
−9
μg, and corresponds to three to six DNA molecules having a molecular weight of 1.6 × 10
7
.
Inhibition of De Novo Purine Biosynthesis and Interconversion by 6-Methylpurine in
Escherichia coli
Authors: Benson Charles E. , Love Samuel H. , Remy Charles N.
Published: January 2020

The inhibition of
Escherichia coli
strain B and strain W-11 by 6-methylpurine depended on the formation of 6-methylpurine ribonucleotide by the action of adenine phosphoribosyltransferase (AMP: pyrophosphate phosphoribosyltransferase, EC 2.4.2.7). 6-Methylpurine ribonucleotide inhibited the de novo synthesis of purines, presumably via pseudofeedback inhibition of phosphoribosylpyrophosphate amidotransferase (EC 2.4.2.14). The same mechanism accounted for its inhibition of adenylosuccinate synthetase [IMP:
l
-aspartate ligase (GDP), EC 6.3.4.4]. Adenine and 6-methylaminopurine prevented inhibition by competing for the action of adenine phosphoribosyltransferase. In addition, adenine reversed this inhibition by replenishing the AMP to bypass both sites of inhibition. Nonproliferating suspensions of strain B-94, which lacked adenylosuccinate lyase (EC 4.3.2.2), converted exogenous hypoxanthine and aspartate to succinoadenine derivatives which accumulated in the medium. Compounds which inhibited adenylosuccinate synthetase inhibited accumulation of the succinoadenine derivatives. A method was described for the isolation of mutants which potentially possessed an altered adenylosuccinate synthetase.
Conversion of Histidine to Hercynine by
Neurospora crassa
Authors: Reinhold Vernon N. , Ishikawa Yoshinori , Melville Donald B.
Published: January 2020

Cell-free extracts of
Neurospora crassa
mycelium catalyze the methylation of
l
-histidine to form hercynine (histidine betaine). The partially methylated compounds, α-
N
-methyl-
l
-histidine and α-
N,N
-dimethyl-
l
-histidine, are also methylated by the same enzyme preparation to form hercynine. All three methylation reactions are stimulated by the addition of
S
-adenosylmethionine.
Isolation of Mutants of
Staphylococcus aureus
Lacking Extracellular Nuclease Activity
Authors: Omenn Gilbert S. , Friedman John
Published: January 2020

Suspensions of
Staphylococcus aureus
Foggi strain were exposed to nitrosoguanidine and screened on deoxyribonucleic acid-acridine orange-agar plates for loss of extracellular nuclease activity. All nuclease-deficient mutants lacked cross-reacting material when tested with antinuclease antibody. Coagulase and β-hemolysin were also lost in nuclease-deficient mutants, and all three enzyme functions were regained together upon reversion with ethyl methane sulfonate. These observations are consistent with the suggestion that the synthesis or the release, or both the synthesis and release, of certain extracellular enzymes may be subject to coordinated control mechanisms.
Aerobic Heterotrophic Bacteria Indigenous to
p
H 2.8 Acid Mine Water: Microscopic Examination of Acid Streamers
Authors: Dugan Patrick R. , MacMillan Carol B. , Pfister Robert M.
Published: January 2020

“Acid streamers” found in acid coal mine drainage consist of bacteria trapped within an extracellular fibrillar polymer network. Inorganic compounds also precipitate within the polymer network. Several bacteria which appear to be different and are presumed to be different species are associated in the slimy mass of the “acid streamers.” The “streamers” contain individual microcolonies or microcosms that can be recognized by a selective polysaccharide stain, which suggests that the slime streamer is a conglomeration of polymers produced by more than one species.
Biochemistry ofCoxiella burnetti:6-Phosphogluconic Acid Dehydrogenase
Authors: McDonald Thomas L. , Mallavia L.
Published: January 2020

Purified preparations of the rickettsial agent,Coxiella burnetii, have been examined for their ability to decarboxylate 6-phosphogluconate. The enzyme 6-phosphogluconic acid dehydrogenase [6-phospho-d-gluconate: NADP (nicotinamide adenine dinucleotide phosphate) oxidoreductase (decarboxylating), EC 1.1.1.44] was detected in extracts, but not in whole-cell preparations ofC. burnetii. Both extracts and whole cells were shown to be free from contaminating host enzyme activity. Partial characterization of the enzyme has shown that it is substrate-dependent, specific for NADP, and requires magnesium for activity. ThepH optimum of the rickettsial enzyme is 8.0.
Endonuclease from
Micrococcus luteus
Which Has Activity Toward Ultraviolet-Irradiated Deoxyribonucleic Acid: Purification and Properties
Authors: Carrier W. L. , Setlow R. B.
Published: January 2020

An endonuclease purified ∼3,200-fold from
Micrococcus luteus
is active on native ultraviolet-irradiated deoxyribonucleic acid (DNA), but is inactive on unirradiated native or denatured DNA and has no activity toward irradiated denatured DNA. The major type of lesion for the nucleolytic activity is the cyclobutane pyrimidine dimer. The enzyme makes a number of single-strand breaks approximately equal to the number of dimers, but dimers are not excised. This endonuclease—a small molecular weight protein—therefore has all the attributes hypothesized for the first enzyme in the sequential steps in repair of DNA in vivo. Another paper shows that the endonuclease is able to reactivate ultraviolet-irradiated transforming DNA.
Some Biological Effects of Carbamoyloxyurea, an Oxidation Product of Hydroxyurea
Authors: Rosenkranz Herbert S.
Published: January 2020

Carbamoyloxyurea, an oxidation product of hydroxyurea, is bactericidal for
Escherichia coli
. Drug-induced killing is independent of cellular metabolism; ribonucleic acid and protein syntheses are the processes most affected, and the lethal action is accompanied by degradation of cellular deoxyribonucleic acid. In all of these effects the drug differs from hydroxyurea, a primarily bacteriostatic agent that inhibits deoxyribonucleic acid synthesis, whose lethal action ultimately depends on cellular activity.
Resistance Transfer to the Resident Intestinal
Escherichia coli
of Rats
Authors: Guinée P. A. M.
Published: January 2020

The transfer of resistance factors from introduced donor cells to the resident intestinal
Escherichia coli
flora of conventional rats was tested.
Arginaseless
Neurospora
: Genetics, Physiology, and Polyamine Synthesis
Authors: Davis Rowland H. , Lawless Mary B. , Port Loretta A.
Published: January 2020

Four arginaseless mutants of
Neurospora crassa
have been isolated. All carry mutations which lie at a single locus,
aga
, on linkage group VIIR. A study of
aga
strains shows the arginase reaction to be the major, perhaps the only, route of arginine consumption in
Neurospora
other than protein synthesis. Ornithine-δ-transaminase, the second enzyme of the arginine catabolic pathway, is present and normally inducible by arginine in
aga
strains, and ornithine transcarbamylase, an enzyme of arginine synthesis, also has normal activity. Arginine inhibits the growth of
aga
strains. The inhibition can be reversed by spermidine, putrescine (1,4-diaminobutane), or ornithine. The results suggest that ornithine is the major source of the putrescine moiety of polyamines in
Neurospora
, and that putrescine is an essential growth factor for this organism. The inhibition of
aga
strains by arginine can be attributed to feedback inhibition of ornithine synthesis by arginine, combined with the complete lack of ornithine normally provided by the arginase reaction.
Biochemical and Histochemical Localization of Invertase in
Neurospora crassa
During Conidial Germination and Hyphal Growth
Authors: Chung Patricia L. Y. , Trevithick John R.
Published: January 2020

The intracellular localization of
Neurospora
invertase, an enzyme partially secreted and partially retained by
Neurospora
at the cell periphery, was investigated. A cell wall fraction was isolated, to which 24% of the cell-bound invertase was firmly attached. A sensitive osmiophilic stain for invertase was developed and used in conjunction with the technique of indirect immunofluorescence to follow the pattern of invertase localization during the development of
Neurospora
from the germination of conidia to the mature hypha. These studies revealed that: (i) conidial invertase was uniformly distributed along the cell periphery; (ii) growing hyphal tips of germinating conidia showed pronounced invertase activity as the rest of the conidial cell wall lost its peripheral activity; (iii) hyphae in early log-phase growth had strong enzyme activity associated with the cell wall, and in late log phase the activity became associated with the plasma membrane and points where new hyphal branches were being formed; and (iv) hyphae in early stationary phase had strong fluorescence at incipient branching points, in “dots” close to the plasma membrane, and in the cytoplasm.
Taxonomic Implications of Temperature Dependence of the Allosteric Inhibition of 3-Deoxy-
d
-
arabino
-Heptulosonate 7-Phosphate Synthetase in
Bacillus
Authors: Jensen Roy A.
Published: January 2020

The qualitative pattern of control for 3-deoxy-
d
-
arabino
-heptulosonate 7-phosphate (DAHP) synthetase is a stable and strongly conserved trait of related bacteria and constitutes a reliable generic character. In
Bacillus
, the generic control pattern for DAHP synthetase is sequential feedback inhibition, a regulatory pattern in which branch-point metabolites are feedback inhibitors. Member species of this genus have DAHP synthetases which vary quantitatively in the effect of temperature upon the sensitivity of the enzyme to feedback inhibition by prephenate. The magnitude of this temperature effect has been expressed quantitatively as the allosteric temperature ratio. The species clusters definable by allosteric temperature ratios correlate exceedingly well with subgroups previously distinguished on the basis of sporangial structure. Hence, two independently derived arrangements of
Bacillus
subgroups, depending upon very different methodologies, matched for all but 3 of the 24 species considered. The taxonomic position of these subgroups of the genus
Bacillus
is discussed.
Recovery of Viability and Radiation Resistance by Heat-Injured Conidia of
Penicillium expansum
Lk. ex Thom
Authors: Baldy Richard W. , Sommer N. F. , Buckley Patricia M.
Published: January 2020

Spores heated in water at 54 C for up to 1 hr were plated on nutrient agar immediately or held for 3 days in aerated water at 23 C and then plated. Under these conditions, holding was optimal for recovery, increasing survival percentage up to 20-fold over values for immediate plating. Recovery was prevented partially or completely, however, when spores were held in any of the following solutions: glucose, potassium phosphate, ammonium or sodium acetate, sodium azide, or 2,4-dinitrophenol, or in the sodium or potassium salts of pyruvate, and tricarboxylic acid cycle acids. Both anaerobiosis and incubation at 0 C prevented recovery. Survivors of a heat treatment were more sensitive to gamma radiation than were unheated spores. Conditions which affected the recovery of viability had the same effect on restoration of radiation resistance. Thus, many of the processes for restoration of radiation resistance seem involved also in recovery of viability after heating. After a 99% inactivating treatment (about 30 min at 54 C), heated spores respired as fast as unheated spores, or faster. Malate, citrate, succinate, and acetate stimulated respiration in unheated spores and inhibited it in heated spores.
Ultrastructure of
Escherichia coli
Depleted of an Amino Acid
Authors: Morgan Councilman , Rosenkranz Herbert S.
Published: January 2020

Particles accumulating during amino acid starvation of
Escherichia coli
C600 are described and illustrated.
Abortive Transduction of Resistance Factor by Bacteriophage P22 in
Salmonella typhimurium
Authors: Watanabe Tsutomu , Ogata Yasuko
Published: January 2020

When R factor 222 is transduced by bacteriophage P22 in
Salmonella typhimurium
, most recipient bacteria which adsorb transducing particles do not give rise to transductant clones (i.e., transduction is abortive); however the transduced drug-resistance genes can be rescued by recombination with the resistance-transfer factor or R factor carried by the recipient.
Genetic Regulation of Ribonucleoside and Deoxyribonucleoside Catabolism in
Salmonella typhimurium
Authors: Robertson B. C. , Jargiello P. , Blank J. , Hoffee Patricia A.
Published: January 2020

Four enzymes involved in ribonucleoside and deoxyribonucleoside catabolism (deoxyribose-5-P aldolase, thymidine phosphorylase, phosphodeoxyribomutase, and purine nucleoside phosphorylase) are coded for by four closely linked structural genes on the
Salmonella
chromosome. The genetic order of these genes is (
deoC-deoA-deoB-deoD
)-
serB-thr
. Studies on polarity mutants and induction patterns indicate that the
deoB
and
deoD
genes may constitute a single operon and that the
deoC
and
deoA
genes may constitute a second closely linked operon.
Effect of Putative Deoxyribonucleic Acid Inhibitors on Macromolecular Synthesis in
Saccharomyces cerevisiae
Authors: Wehr C. T. , Kudrna R. D. , Parks L. W.
Published: January 2020

The effects of inhibitors of bacterial deoxyribonucleic acid (DNA) synthesis upon logarithmically growing cultures of
Saccharomyces cerevisiae
were investigated. Cell division, ribonucleic acid (RNA) synthesis, and DNA synthesis were measured after addition of nalidixic acid, fluorodeoxyuridine, or phenethyl alcohol to cultures of yeast growing in defined and complex media. Both nalidixic acid and fluorodeoxyuridine had only temporary effects on nucleic acid synthesis in cultures growing in defined medium, and little or no observable effect on cultures growing in complex medium. Neither compound inhibited colony formation on complex solid medium, although growth was slow on defined solid medium. Phenethyl alcohol caused complete inhibition of DNA synthesis, RNA synthesis, and cell division in cultures growing in defined medium. In cultures growing in complex medium, RNA synthesis and cell division were inhibited to a lesser extent. A slight increase in DNA was observed in the presence of the inhibitor.
Polysome Stability in Relaxed and Stringent Strains ofEscherichia coliDuring Amino Acid Starvation
Authors: Sells Bruce H. , Ennis Herbert L.
Published: January 2020

The influence of amino acid starvation on polysome content was examined in relaxed and stringent strains ofEscherichia coliwhich were isogenic for the RC locus. No difference was observed between the polysome profiles obtained from two different sets of stringent and relaxed strains starved for the same amino acid. In both relaxed and stringent strains, starvation for amino acids other than methionine resulted in only a slight breakdown of polysomes with a concomitant increase of 70Sribosomes. However, starvation for methionine in both RC stringent and relaxed strains ofE. coliresulted in a more extensive degradation of polysomes and accumulation of 70Sribosomes. The 70Sribosomes obtained as a result of methionine starvation were more sensitive to degradation to 50 and 30Ssubunits in 10−3mMg2+than 70Smonomers obtained either by degradation of polysomes with ribonuclease or by starvation of cells for amino acids other than methionine. The 70Sribosomes from methionine starvation were similar (sensitivity to 10−3mMg2+) to 70Sribosomes obtained from cells in which initiation of protein synthesis had been prevented by trimethoprim, an inhibitor of formylation. SinceN-formyl-methionyl-transfer ribonucleic acid is required for initiation, the 70Sribosomes obtained in both methionine-starved and trimethoprim-treated cells must result from association of 50 and 30Ssubunits for reasons other than reinitiation. These results suggest that the level of ribonucleic acid synthesis does not influence the distribution of ribosomes in the polysome profile and vice versa.
Polyphosphate and Orthophosphate Content of
Nitrosomonas europaea
as a Function of Growth
Authors: Terry K. R. , Hooper A. B.
Published: January 2020

After inoculation of a stationary-phase culture of
Nitrosomonas europaea
into fresh growth solution, the cell-associated orthophosphate increased rapidly to 800 μmoles/g (wet weight), whereas the acid-insoluble long-chain polyphosphate content decreased rapidly to 22 μmoles/g. As growth proceeded, the orthophosphate content decreased rapidly to a level of 15 μmoles/g and the long-chain polyphosphate content gradually increased to 60 to 90 μmoles/g. When the
p
H of a culture of
Nitrosomonas
decreased during growth below approximately 7.4, the rate of nitrite and polyphosphate synthesis increased and the ratio of change in protein to change in nitrite decreased. When the
p
H of the culture was maintained above 7.6 throughout growth, polyphosphate accumulation, an increased rate of nitrite and polyphosphate synthesis, and a decreased ratio of change in protein to change in nitrite were not observed. Cells of
Nitrosomonas
apparently accumulated polyphosphate when adenosine triphosphate generated during the oxidation of ammonia to nitrite was not efficiently used to promote an increase in cell mass. The rapid hydrolysis of polyphosphate after the transfer of stationary-phase cells into fresh growth solution was found to be triggered primarily by the higher
p
H of the fresh growth solution. The efflux of orthophosphate during culture growth was not associated with a decrease in the
p
H of the growth solution. Data on the chemical composition of
Nitrosomonas
are presented.
Steady-State Measurement of the Turnover of Amino Acid in the Cellular Proteins of Growing
Escherichia coli
: Existence of Two Kinetically Distinct Reactions
Authors: Pine Martin J.
Published: January 2020

Turnover of cellular protein has been estimated in
Escherichia coli
during continuous exponential growth and in the absence of extensive experimental manipulation. Estimation is based upon the cumulative release into carrier pools of free leucine-
1
-
14
C
over a number of time intervals after its pulsed incorporation into protein. Breakdown rates obtained with other labeled amino acids are similar to those obtained with leucine. Two kinetically separate processes have been shown. First, a very rapid turnover of 5% of the amino acid label occurs within 45 sec after its incorporation, most likely indicating maturative cleavages within the proteins after their assembly. A slower heterogeneous rate of true protein turnover follows, falling by 39% in the remaining proteins for each doubling of turnover time. At 36 C, the total breakdown rate of cellular protein is 2.5 and 3.0% per hr over a threefold range of growth rate in glucose and acetate medium, respectively. This relatively constant breakdown rate is maintained during slower growth by more extensive protein replacement, one fifth of the protein synthesized at any time in the acetate medium being replaced after 4.6 doubling times. Intracellular proteolysis thus appears to be a normal and integral reaction of the growing cell. The total rate equals minimal estimates obtained by others for arrested or decelerated growth but is kinetically more heterogeneous. Quantitatively proteolysis is not directly affected by growth arrestment per se as caused by α-methylhistidine, chloramphenicol, or uncouplers of oxidative phosphorylation, but qualitatively it can gradually become more homogeneous kinetically as a secondary event of starvation. Under more extreme conditions as with extensive washing, prolonged phosphorylative uncoupling, or acidification of the growth medium, the proteolytic rate can increase severalfold.
Macromolecular Subunits in the Walls of Marine Photosynthetic Bacteria
Authors: Remsen Charles C. , Watson Stanley W. , Trüper Hans G.
Published: January 2020

Electron micrographs of sectioned and frozen-etched marine species of
Chromatium
revealed that at least two different patterns of macromolecular subunits are present on the cell wall.
cis-Dichlorodiammineplatinum(II): Cytological Changes Induced in Escherichia coli
Authors: Howle Jerry A. , Gale Glen R.
Published: January 2020

Filamentous forms of
Escherichia coli
, induced by growth in the presence of
cis
-dichlorodiammineplatinum(II), contain amorphous inclusion aggregates, possibly ribosomal, with an affinity for uranium ion.
Activation Energy for Glucose-Induced Germination of
Bacillus megaterium
Spores
Authors: Levinson Hillel S. , Hyatt Mildred T.
Published: January 2020

The maximum germination rate of
Bacillus megaterium
QM B1551 spores in glucose increased, and the lag before its attainment decreased, with increasing germination temperature. The activation energy for germination (μ = approximately 20 kcal/mole), based on rate or on lag, was consistent with an enzymatic mechanism.
Control of Colanic Acid Synthesis
Authors: Grant W. D. , Sutherland I. W. , Wilkinson J. F.
Published: January 2020

The nucleotide pools of certain mucoid, colanic acid-synthesizing strains of
Escherichia coli, Salmonella typhimurium
, and
Aerobacter cloacae
were examined, and in all cases the nucleotide sugars uridine-5′-diphosphate glucose (UDPG), uridine-5′-diphosphate galactose (UDPGal), guanosine-5′-diphosphate fucose (GDPF), and uridine-5′-diphosphate glucuronic acid (UDPGA) were detected. It is postulated that these nucleotide sugars are precursors in the synthesis of colanic acid. The levels of these nucleotide sugars and of the enzymes involved in their synthesis were examined in a number of mucoid strains and compared with the levels found in certain strains which were repressed in the synthesis of colanic acid, only becoming mucoid when grown in the presence of
p
-fluorophenylalanine (PFA). The levels of UDPG and UDPGal and the enzymes involved in their synthesis were substantially the same in both mucoid and repressed types, but the levels of UDPGA and GDPF and of some of the enzymes involved in their synthesis were much higher in mucoid strains. When repressed strains were grown in the presence of PFA, the levels of UDPGA and GDPF approached those found in mucoid strains. The existence of an operon, containing genes coding for certain key enzymes involved in colanic acid synthesis has been suggested.
Biosynthesis of the Branched-Chain Amino Acids in Yeast: a Trifluoroleucine-Resistant Mutant with Altered Regulation of Leucine Uptake
Authors: Bussey Howard , Umbarger H. E.
Published: January 2020

A trifluoroleucine-resistant mutant of yeast has been isolated that exhibits reduced incorporation of the analogue into protein (15%) of that in the wild type. In the mutant, uptake of the analogue and leucine into the expandable (water-extractable) pool is enhanced, passage from the expandable to the conversion (nonwater-, ethanol-extractable) pool is unaffected, and endogenous synthesis of leucine is normally regulated. Although the leucyl transfer ribonucluic acid (tRNA) synthetase appears normal, and the tRNA
leu
has wild-type acceptor activities in vitro and in vivo, the level of the mutant trifluoroleucyl tRNA pool is only 2 to 3% of that in the wild type. The data support the idea of a mutation affecting passage between the conversion pool and the site of charging of the analogue. The mutation is dominant and exhibits pleiotropic effects: the first leucine biosynthetic enzyme appears nonrepressible, and the leucine, valine, and tyrosine uptake systems are constitutively elevated (three- to fourfold) in the absence of exogenous amino acids.
Differential Depression of Staphylococcal Plasmid and Chromosomal Penicillinase Genes by a Class of Unlinked Chromosomal Mutations (R2
−
)
Authors: Cohen S. , Vernon E. G. , Sweeney H. M.
Published: January 2020

We described previously a class of mutations (phenotypic designation R2
−
) in
Staphylococcus aureus
that were unlinked to penicillinase genes but nevertheless imposed constitutive synthesis of this enzyme upon wild-type plasmids. The plasmids affected by these mutations have been found to possess the same maintenance-compatibility type (I) and to form penicillinase of serotype A. Three plasmids that had a different maintenance-compatibility type (II) and formed penicillinase of serotype C were only slightly derepressed in R2
−
mutants. Three chromosomal penicillinase genes were variably derepressed, the range extending from negligible to nearly complete derepression. The differences in degree of derepression among the three types of penicillinase linkage groups were tentatively ascribed to position effects.
Tryptophan Transport in
Neurospora crassa:
a Tryptophan-Binding Protein Released by Cold Osmotic Shock
Authors: Wiley W. R.
Published: January 2020

Osmotic shock treatment of germinated conidia of
Neurospora
reduced the capacity for tryptophan transport in these cells approximately 90% without an appreciable loss of cell viability. Tryptophan-binding proteins and alkaline phosphatase were consistently released into the osmotic shock fluid by this treatment. Four lines of evidence suggest that the binding protein may be related to the tryptophan transport system. (i) It appears to be located on or near the cell surface. (ii) a decreased capacity for binding tryptophan was observed in shock fluids from cells repressed for tryptophan uptake; reduced or altered binding capacity was released from a transport-negative mutant. (iii) The specificity of tryptophan binding was similar to that observed in the in vivo transport system. (iv) The dissociation constant for binding, as measured by equilibrium dialysis, was approximately the same as the
K
m
for tryptophan transport.
Multiplicity of the Amino Acid Permeases in
Saccharomyces cerevisiae
IV. Evidence for a General Amino Acid Permease
Authors: Grenson M. , Hou C. , Crabeel M.
Published: January 2020

Kinetic and genetic evidences are presented to show that, in addition to specific amino acid permeases,
Saccharomyces cerevisiae
has a general amino acid permease which catalyzes the transport of basic and neutral amino acids, but most probably not that of proline. The general amino acid permease appears to be constitutive, and its activity is inhibited when ammonium ions are added to the culture medium. A mutant which has lost the general amino acid permease activity was isolated. Its mutation, named
gap
(general amino acid permease), is not allelic to the
aap
(amino acid permease) mutation of Surdin et al., which has a quite different phenotype and cannot be considered as having selectively lost the general amino acid permease activity.
Ultrastructure of a Temperature-Sensitive Rod
−
Mutant of
Bacillus subtilis
Authors: Cole Roger M. , Popkin Terry J. , Boylan Robert J. , Mendelson Neil H.
Published: January 2020

Mutant 168ts-200B, resulting from nitrosoguanidine treatment of
Bacillus subtilis
168 (
trp
−
C2), exhibits a rod-to-sphere morphogenetic interconversion when the incubation temperature is 30 or 45 C, respectively. Ultrathin sections of rods grown at 30 C, after glutaraldehyde-osmium uranium-lead fixation and staining, show trilaminar cell walls with a well-developed underlying periplasm as in wild-type cells. However, the outer wall layer is irregular, and abnormal protrusions of wall material occur at the cross-walls. In contrast, cells growing at 45 C become rounded and are intersected randomly by irregular cross-walls which fail to split normally, resulting in large spherical masses. In these, the outer and inner wall layers and periplasm are lost, and the wall consists only of irregularly thickened and loosely organized middle layer. Wall ultrastructure is reversible in either direction as cell shape changes during temperature shifts. Mesosomes are rare and atypical at either temperature. It thus appears that cell wall ultrastructure is altered by the conditional (temperature-sensitive) mutation, and that loss of normal wall and submural organization is correlated with changes in cell size and shape as well as with inability to complete cell division. Preliminary studies after transformation of the mutant locus to another strain and growth at 45 C showed an increase in mucopeptide, loss of wall teichoic acid, failure of phage adsorption, and identical ultrastructural changes. The site of expression of the basic defect—be it in wall, submural region, or membrane—is undetermined.
l
-Serine-Sensitive Mutants of
Escherichia coli
K-12
Authors: Cosloy Sharon D. , McFall Elizabeth
Published: January 2020

While attempting to isolate
d
-serine-sensitive mutants of
Escherichia coli
K-12, we found a class of mutants sensitive to low concentrations of
l
-serine (10 to 25 μg/ml).
Phospholipid Metabolism During Penicillinase Production in
Bacillus licheniformis
Authors: Morman Manuel R. , White David C.
Published: January 2020

During membrane-bound penicillinase production,
Bacillus licheniformis
forms vesicles and tubules that do not appear in the absence of penicillinase production. The major lipids of
B. licheniformis
were shown to be phospholipids. The proportions, metabolism, and the total phospholipid per cell were shown to be essentially the same in the uninduced control, induced and constitutive penicillinase forming cells during both the exponential and stationary growth phases. Membrane phospholipids were not secreted into the medium during penicillinase formation. In the shift from the exponential to the stationary growth phase, there was an accumulation of phosphatidyl glycerol and a marked decrease in cardiolipin. These two lipids had the most active turnover of their phospholipid phosphate of all the lipids studied.
Polyphasic Taxonomy of the GenusVibrio:Numerical Taxonomy ofVibrio cholerae, Vibrio parahaemolyticus, and RelatedVibrioSpecies
Authors: Colwell R. R.
Published: January 2020

A set of 86 bacterial cultures, including 30 strains ofVibrio cholerae, 35 strains ofV. parahaemolyticus, and 21 representative strains ofPseudomonas, Spirillum, Achromobacter, Arthrobacter, and marineVibriospecies were tested for a total of 200 characteristics. Morphological, physiological, and biochemical characteristics were included in the analysis. Overall deoxyribonucleic acid (DNA) base compositions and ultrastructure, under the electron microscope, were also examined. The taxonomic data were analyzed by computer by using numerical taxonomy programs designed to sort and cluster strains related phenetically. TheV. choleraestrains formed an homogeneous cluster, sharing overall S values of ≥75%. Two strains,V. choleraeNCTC 30 and NCTC 8042, did not fall into theV. choleraespecies group when tested by the hypothetical median organism calculation. No separation of “classic”V. cholerae, El Tor vibrios, and nonagglutinable vibrios was observed. These all fell into a single, relatively homogeneous,V. choleraespecies cluster.V. parahaemolyticusstrains, excepting 5144, 5146, and 5162, designated members of the speciesV. alginolyticus, clustered at S ≥80%. Characteristics uniformly present in all theVibriospecies examined are given, as are also characteristics and frequency of occurrence forV. choleraeandV. parahaemolyticus. The clusters formed in the numerical taxonomy analyses revealed similar overall DNA base compositions, with the range for theVibriospecies of 40 to 48% guanine plus cytosine. Generic level of relationship ofV. choleraeandV. parahaemolyticusis considered dubious. Intra- and intergroup relationships obtained from the numerical taxonomy studies showed highly significant correlation with DNA/DNA reassociation data.
Synthetic Capabilities of Plasmolyzed Cells and Spheroplasts of
Escherichia coli
Authors: Rubenstein Kenneth E. , Nass Margit M. K. , Cohen Seymour S.
Published: January 2020

Effects of plasmolysis and spheroplast formation on deoxyribonucleic acid (DNA), ribonucleic acid (RNA), protein, and phospholipid synthesis by
Escherichia coli
strain THU were studied. RNA and protein synthesis were severely diminished. DNA and phospholipid synthesis were inhibited, but less so; they could be partly restored. DNA synthesis could be restored by replacing thymine in the medium with thymidine, and phospholipid synthesis, by adding back small quantities of soluble cell extract. Plasmolysis effected marked reductions in rates of growth and macro-molecule synthesis, and temporarily reduced culture viability. Plasmolysis also caused an anomalous stimulation of phospholipid synthesis. Spheroplasts and plasmolyzed cells synthesized small amounts of ribosomal RNA that sedimented normally. However, this ribosomal RNA was very inefficiently packaged to ribosome subunits. Spheroplasts were unable to carry out induced synthesis of β-galactosidase, and plasmolyzed cells were delayed in this function. Radioautographs examined in an electron microscope showed that DNA synthesis in plasmolyzed cells and spheroplasts was performed by a substantial fraction of the culture populations. That DNA and membrane were associated in the spheroplasts used in this study was suggested by formation of M-bands containing membrane and most of the cell's DNA. The results are discussed in terms of alterations of membrane structure and conformation attending plasmolysis and spheroplasting.
Lysis of Blue-Green Algae by Myxobacter
Authors: Shilo Miriam
Published: January 2020

Enrichment from local fishponds led to the isolation of a bacterium capable of lysing many species of unicellular and filamentous blue-green algae, as well as certain bacteria. The isolate is an aflagellate, motile rod which moves in a gliding, flexuous manner; the organism is capable of digesting starch and agar, but not cellulose and gelatin. Its deoxyribonucleic acid base pair composition (per cent guanine plus cytosine ∼70) shows a close resemblance to that of the fruiting myxobacteria. Algae in lawns on agar plates were lysed rapidly by the myxobacter, but only limited and slow lysis occurred in liquid media, and no lysis took place when liquid cultures were shaken. No diffusible lytic factors would be demonstrated. Continuous observation of the lytic process under a phase-contrast microscope suggested that a close contact between the polar tip of the myxobacter and the alga is necessary for lysis. The lytic action is limited to the vegetative cells of the algae, whereas heterocysts are not affected. The gas vacuoles of the algal host are the only remnant visible after completion of digestion by the myxobacter.
Anaerobic Growth of Purple Nonsulfur Bacteria Under Dark Conditions
Authors: Uffen Robert L. , Wolfe R. S.
Published: January 2020

Purple nonsulfur photosynthetic bacteria were cultured anaerobically in the absence of light by a modification of the Hungate technique. Growth was slow and resembled that of fastidious anaerobes; on yeast extract-peptone-agar medium, each cell produced about 16 descendants in 15 to 20 days. Growth was stimulated by addition of ethyl alcohol, acetate and H
2
, or pyruvate and H
2
. Cells grown in the presence of pyruvate and H
2
produced acetate and CO
2
; each cell produced approximately 10 descendants in 24 hr under anaerobic, dark conditions. Spectrophotometric evidence obtained from cells which were the product of five generations suggests no difference between the bacteriochlorophyll and carotenoids synthesized by cells grown anaerobically under dark or light conditions. Likewise, the ultrastructure of the photosynthetic apparatus in cells grown anaerobically in the dark and in the light appears similar.
Biochemical and Cytochemical Evidence for the Polar Concentration of Periplasmic Enzymes in a “Minicell” Strain of
Escherichia coli
Authors: Dvorak Harold F. , Wetzel Bruce K. , Heppel Leon A.
Published: January 2020

A number of “surface” enzymes of
Escherichia coli
(i.e., among those selectively released by osmotic shock) all displayed higher specific activities in extracts of minicells than in extracts of typical rod forms; these enzymes included alkaline phosphatase, cyclic phosphodiesterase, acid hexose monophosphatase, 5′-nucleotidase, and ribonuclease I. In addition, alkaline phosphatase, cyclic phosphodiesterase, and acid hexose monophosphatase were cytochemically localized to regions of minicell periplasm that resembled reactive polar enlargements of the periplasm in rod forms. In contrast, a number of “internal” cytoplasmic enzymes (inorganic pyrophosphatase, β-galactosidase, glutamine synthetase, polynucleotide phosphorylase, and ribonuclease II) showed elevated or similar specific activities in extracts of rod forms versus extracts of minicells. A specific heat-labile inhibitor for 5′-nucleotidase, known to occur in the cytoplasm, also showed no enrichment in minicells. These findings indicate that the “surface” enzymes are segregated in vivo into the terminal minicell buds, possibly because these enzymes are concentrated in the polar enlargements of the periplasm in typical rod forms.
Induction of Histidine-Degrading Enzymes in
Pseudomonas aeruginosa
Authors: Newell C. P. , Lessie T. G.
Published: January 2020

Urocanate but not histidine was able to induce formation of histidine-degrading enzymes in a histidine ammonia-lyase-deficient mutant of
Pseudomonas aeruginosa
. The results, in conjunction with others reported previously, indicate that urocanate, the first intermediate, is the physiological inducer of the pathway.
Impurity in a Common Growth Medium Component: Presence of an Isoflavonoid in Samples of
l
-Asparagine
Authors: Hudson A. T. , Bentley Ronald
Published: January 2020

An impurity, present in some samples of
l
-asparagine, gave genistein on acid hydrolysis. The contaminant (probably the glucoside of genistein) was metabolized by
Mycobacterium phlei
to genistein and prunetin.
Cellular Fatty Acids of Pathogenic
Neisseria
Authors: Moss C. Wayne , Kellogg D. S. , Farshy D. C. , Lambert M. A. , Thayer J. D.
Published: January 2020

The cellular fatty acid composition of 20 isolates of
Neisseria gonorrhoeae
and 21 isolates of
N. meningitidis
was examined by gas-liquid chromatography. Each isolate of the two species possessed similar fatty acid profiles which were characterized by five major acids, accounting for 80 to 85% of the total. The three most abundant acids in each species were palmitic, palmitoleic, and β-hydroxylauric acids; lauric and myristic acids were the next most abundant. The presence of large amounts of β-hydroxylauric acid (20% or greater) and the relative concentrations of the other four major acids appear to be useful markers for distinguishing
N. gonorrhoeae
and
N. meningitidis
fatty acids from those of other bacteria.
Inhibition by Phenylalanine of Thiazole Biosynthesis in
Escherichia coli
Authors: Iwashima Akio , Nose Yoshitsugu
Published: January 2020

Phenylalanine inhibited thiazole biosynthesis in a thiamine-regulatory mutant of
Escherichia coli
, and the inhibition was overcome by tyrosine.
Regulation of
S
-Adenosylmethionine Synthetase in
Escherichia coli
Authors: Holloway Caroline T. , Greene Ronald C. , Su Ching-Hsiang
Published: January 2020

Addition of methionine to the growth medium of
Escherichia coli
K-12 leads to a reduction in the specific activity of
S
-adenosylmethionine (SAM) synthetase. Thus the enzyme appears to be repressible rather than inducible. Mutant strains (probably metJ
−
) are constitutive for SAM synthetase as well as for the methionine biosynthetic enzymes, suggesting that the regulatory systems for these enzymes have at least some elements in common. Cells grown to stationary phase in complete medium, which have low specific activities of the enzymes, were routinely used for derepression experiments. The lag in growth and derepression when these cells are incubated in minimal medium is shortened by threonine. Ethionine, norleucine, and α-methylmethionine are poor substrates or nonsubstrates for SAM synthetase and are ineffective repressors. Selenomethionine, a better substrate for SAM synthetase than methionine, is also slightly more effective at repression than methionine. Although SAM is considered to be a likely candidate for the corepressor in the control of the methionine biosynthetic enzymes, addition of SAM to the growth medium does not cause repression. Measurement of SAM uptake shows that too little is taken into the cells to have a significant effect, even if it were active in the control system.
Ultrastructural Changes and Biochemical Events in Basidiospore Germination of
Schizophyllum commune
Authors: Aitken W. Brent , Niederpruem Donald J.
Published: January 2020

Electron microscopic features and biochemical events were outlined in basidiospore germination of
Schizophyllum commune
. Normal ultrastructural changes included prominent vacuolization and more abundant endoplasmic reticulum. A lag phase in outgrowth included depletion of cellular reserves of trehalose, mannitol, and arabitol and subsequent increases in ribonucleic acid and protein. Depletion of polyols required exogenous carbon and nitrogen sources and was arrested by protein synthesis antagonists. Outgrowth subsequent to the lag period was accompanied by increased glycogen deposition and alkali-soluble glucan production.
Role of Pyridine Nucleotides in the Control of Respiration in Ultraviolet-Irradiated
Escherichia coli
B/r Cells
Authors: Swenson P. A. , Schenley R. L.
Published: January 2020

Escherichia coli
B/r cells grown on glycerol-containing medium and irradiated with ultraviolet light to about 1% survival respire for about 1 hr and then cease completely for several hours. The results of studies on cell-free respiration and analyses of pyridine nucleotide levels at various times after ultraviolet irradiation show that the cessation of respiration is associated with two changes—loss of glycerol kinase activity and complete disappearance of pyridine nucleotides. Under other cultural conditions in which respiratory inhibition is less complete and more transitory, the losses of pyridine nucleotides are smaller and the rises which follow are correlated with increases in respiratory activity.
Quantitation, Chemical Characteristics, and Ultrastructure of the Three Outer Cell Wall Layers of a Gram-Negative Bacterium
Authors: Forsberg C. W. , Costerton J. W. , MacLeod Robert A.
Published: January 2020

The cell wall of the gram-negative marine pseudomonad (American Type Culture Collection 19855) consists of three layers: the loosely bound outer layer, the outer double-track layer, and the underlying layer. These three layers constitute 4.7, 7.9, and 6.1%, respectively, of the dry weight of the whole cells. All three layers contained protein, lipid, and carbohydrate. The loosely bound outer layer and underlying layer were lower in protein and lipid and higher in amino and nonamino carbohydrate than the outer double-track layer. All three layers contained proteins with similar amino acid compositions. Minicell-like forms attached to the ends of cells were separated with and fractionated from the units of loosely bound outer layer. Examination of negatively stained preparations by electron microscopy revealed the loosely bound outer layer to be composed largely of units ranging from 400 to 1000 nm in diameter. The outer double-track layer, by the same technique, appeared as large, usually rounded sheets, each with a distinct rim. Washing this layer changed the gross chemical composition but did not affect the bimolecular leaflet appearance in thin sections. The underlying layer, when negatively stained, appeared to be composed of a heterogeneous mixture of particles differing in size and shape. It was separated by gel filtration into a large fraction with a molecular weight range in excess of 20 × 10
6
to 40 × 10
6
and a small fraction with a lower range of molecular weight. The larger fraction contained both protein and hexosamine, whereas the smaller one contained protein and only traces of hexosamine. A cytochrome-like pigment separated with this latter fraction.
Mating-Type-Dependent Inhibition of Deoxyribonucleic Acid Synthesis in
Saccharomyces cerevisiae
Authors: Throm E. , Duntze W.
Published: January 2020

Yeast cells of mating type α excrete a sex factor which inhibits cell division and deoxyribonucleic acid replication but not ribonucleic acid or protein synthesis in cells of opposite mating type
a
.
Activation of the C
1
to C
14
Monocarboxylic Acids by a Yeast
Authors: Trust T. J. , Millis Nancy F.
Published: January 2020

Cell extracts of a yeast grown on hexadecane contained a (C
7
to C
14
) acyl-coenzyme A synthetase, acetyl-coenzyme A synthetase, and acetokinase.
Mode of Action of the Antibiotic Siccanin on Intact Cells and Mitochondria of
Trichophyton mentagrophytes
Authors: Nose Keinosuke , Endo Akira
Published: January 2020

Siccanin at 3 μg/ml completely inhibited the growth of
Trichophyton mentagrophytes
. The primary site of action of siccanin on
T. mentagrophytes
is succinate dehydrogenase in the terminal electron transport system. At a concentration of siccanin giving 50% inhibition of growth (0.3 μg/ml), respiration of intact cells was inhibited more strongly than any other cellular functions tested, including the syntheses of cellular ribonucleic acid, deoxyribonucleic acid, phospholipid, protein, and cell wall fractions. In addition, at the same concentration siccanin did not cause any detectable damage in the permeability of the cells. Furthermore, the oxidation of succinate in mitochondrial preparation is more sensitive to the antibiotic than respiration in intact cells. Oxidation of other substrates tested was less sensitive to siccanin than that of succinate. The antibiotic inhibited both phosphorylation and oxidation, without causing changes in the P:O ratio. Siccanin at 0.03 μg/ml, which caused 50% inhibition of succinate oxidation in mitochondria, had effect neither on the exchange reaction between inorganic phosphate (P
i
) and adenosine triphosphate (ATP) nor on that between adenosine diphosphate and ATP. An ATP phosphohydrolase activity was also insensitive to the antibiotic. At very high concentrations, however, the antibiotic slightly inhibited the P
i
-ATP exchange reaction. From those results, it was concluded that siccanin inhibits fungal growth by inhibiting the respiratory electron transport system.