bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of Vitamin K
2
Isoprenologues by
Staphylococcus aureus
Authors: Hammond Ray K. , White David C.
Published: January 2020

In
Staphylococcus aureus
, vitamin K
2
isoprenologues can be labeled with
14
C-acetate, mevalonate, glycerol, α-naphthol, and menadione. All the radioactivity from α-naphthol is in the ring nucleus. Eighty-six per cent of the radioactivity from mevalonate is in the side chain. The labeled isoprenologues of vitamin K
2
can be separated and recovered quantitatively. The rates of incorporation and turnover after pulse-chase experiments indicate that the isoprenologues do not lose radioactivity once they are formed. The kinetics of incorporation of radioactivity into the ring nucleus of each isoprenologue are the same. The alkylation of the ring does not involve a simple sequential addition of isoprenoid units of the same specific activity. The incorporation of mevalonate shows that shorter side chain isoprenologues have a higher specific activity per five carbon unit than the longer side chain isoprenologues. Perhaps the alkyl precursors are from different pools since the kinetics of incorporation into all isoprenologues are different.
Evidence for Two Genes Specifically Involved in Unsaturated Fatty Acid Biosynthesis in
Escherichia coli
Authors: Cronan John E. , Birge Claire H. , Vagelos P. Roy
Published: January 2020

Unsaturated fatty acid auxotrophs of
Eschericha coli
have been divided into two distinct cistrons by extract complementation and genetic complementation based on abortive transduction. Lesions in one cistron result in the loss of the β-hydroxydecanoyl thioester dehydrase which produces the first biosynthetic intermediate in unsaturated fatty acid formation. Evidence is presented which indicates that lesions in the second cistron result in the lack of a second enzyme specifically involved in the biosynthesis of unsaturated fatty acids.
Methyl-Deficient Transfer Ribonucleic Acid in
Saccharomyces cerevisiae
Authors: Phillips John H.
Published: January 2020

Methyl-deficient transfer ribonucleic acid (tRNA) is found in certain methionine auxotrophs of
Saccharomyces cerevisiae
during logarithmic growth (at one generation time before the late growth phase) and during residual growth in the absence of exogenous methionine. The former effect seems to be accounted for by the general increase in RNA synthesis that occurs at the time; there is no specific synthesis of tRNA in the absence of ribosomal RNA synthesis, nor is the methyl group deficiency limited to a single tRNA species. During methionine starvation, all species of tRNA are methyl-deficient, but this occurs only in strains with certain blocks in the methionine pathway. The kinetics of disappearance of the methyl group donor,
S
-adenosylmethionine, during starvation of D73 (which accumulates methyl-deficient tRNA), do not differ from other strains, but D73 loses the methylase inhibitor,
S
-adenosylhomocysteine, much more slowly.
α-Hydroxyglutarate Oxidoreductase of
Pseudomonas putida
Authors: Reitz Marvin S. , Rodwell Victor W.
Published: January 2020

Oxidation of
d
-α-hydroxyglutarate to α-ketoglutarate is catalyzed by
d
-α-hydroxyglutarate oxidoreductase, an inducible membrane-bound enzyme of the electron transport particle [ETP; a comminuted cytoplasmic membrane preparation with enzymic properties and chemical composition resembling beef heart mitochondrial ETP (1)] of
Pseudomonas putida
P2 (P2-ETP). Treatment of P2-ETP with a nonionic detergent yields a preparation with the sedimentation characteristics of a soluble enzyme, but which retains an intact electron transport chain. Oxygen acts solely as a terminal electron acceptor and may be replaced by ferricyanide, 2,6-dichlorophenol indophenol, or mammalian cytochrome
c
. The oxidoreductase is specific for the
d
-isomer (
K
m
= 4.0 × 10
−4
m
for
dl
-α-hydroxyglutarate) and is distinct both from
l
- and
d
-malate dehydrogenases. Spectral studies suggest that the carrier sequence is substrate → flavine or nonheme iron → cyt b → [cyt c] → oxygen.
Deoxycholate-Treated, Nontoxic, Whole-Cell Vaccine Protective Against Experimental Salmonellosis of Mice
Authors: Badakhsh Fred F. , Herzberg Mendel
Published: January 2020

A vaccine prepared from the residue after extraction of whole cells ofSalmonella typhimuriumwith 2% sodium deoxycholate proved to be nontoxic and highly immunogenic. The material was not lethal for mice at 6.0 mg and was essentially nontoxic in rabbit skin, whereas endotoxic activity was found in the dialyzed extract. A high dosage, above 2.0 mg, was less protective than lower doses, indicating a degree of “immunologic paralysis.” Three inoculations of low doses, 0.25 mg each, induced protection against death and tissue infection in animals challenged with 2,000ld50of virulent homologousS. typhimuriumand against death, but not against tissue infection, after heterologous challenge withS. enteritidis. Residues of purified cell walls were as effective as residues of whole cells, indicating that the immunizing antigen(s) resided in the cell wall.
Chromosomal Location of a Gene Involved in Potassium Ion Uptake in
Escherichia coli
B
Authors: Burmeister Maritha
Published: January 2020

A chromosomal lesion responsible for defective potassium ion uptake in
Escherichia coli
B has been mapped by use of standard interrupted-mating crosses. The mutation,
kac-1
, is in strain RD-2, which is deficient in K
+
intake, exchanges cell K
+
for extracellular isotope at a reduced rate, and has an abnormality of phosphorus metabolism associated with its potassium deficiency. This report places
kac-1
at about 4 min clockwise from
pro
, close to
gal
. The locus of
kac-1
is distinctly different from the potassium
retention
mutant in strain B-207, the only other potassium accumulation mutant mapped in
E. coli
so far. In this study, two other potassium accumulation mutations,
kac-2
and
kac-3
, whose particular type of accumulation defects have not yet been determined, were mapped. These mutations are in the same region of the chromosome as
kac-1
.
Carbohydrate Transport in
Clostridium perfingens
Type A
Authors: Groves D. J. , Gronlund Audrey F.
Published: January 2020

Resting-cell suspensions of
Clostridium perfringens
actively transported glucose and mannose but not six other carbohydrates which would support at least limited growth of the microorganism. Competition studies suggested that glucose and mannose were transported by a common mechanism which was highly specific. Analyses of intracellular pools demonstrated that the accumulated carbohydrates were present as phosphorylated derivatives, not as free carbohydrates, and specificity data indicated that phosphorylation occurred at the transport level rather than via the soluble hexokinase.
Effect of Antilymphocyte Serum on Animals Experimentally Infected withHistoplasma capsulatum or Cryptococcus neoformans
Authors: Adamson David M. , Cozad George C.
Published: January 2020

The anti-mouse and anti-guinea pig antilymphocyte sera (ALS) prepared for this study were shown to contain cytoxic and leucoagglutinating antibodies, and were capable of producing severe lymphopenia in these animals. Guinea pigs treated weekly with ALS were more susceptible to development of fatal infection when inoculated withHistoplasma capsulatum. No fatalities occurred in guinea pigs infected with equal doses ofH. capsulatumbut treated with normal rabbit serum (NRS) or saline. The time necessary to reach 50% fatality in mice infected withCryptococcus neoformanswas greatly reduced by pretreatment with ALS in comparison with infected controls treated with NRS or saline. When low dosages were used (0.1ld50), the effect was even more pronounced. Spleen homogenates from mice infected with equal dosages ofH. capsulatumand treated with ALS or NRS were cultured. More than 150 times as many organisms were present in the spleens of the ALS-treated group. Similar results were obtained from culturing the lungs and liver. Delayed hypersensitive skin reactions were radically decreased or abrogated inH. capsulatum-infected guinea pigs inoculated intraperitoneally with ALS 12 hr before skin testing with histoplasmin. When ALS was given weekly, the influence on skin reactivity was less notable. Given intradermally, ALS was shown to inhibit the delayed reaction to histoplasmin within a radius of 40 mm.
Chemistry and End-Group Analysis on Purified M Protein of Type 12 Group A Streptococcal Cell Walls
Authors: Lange Charles F. , Lee Rosita , Merdinger E.
Published: January 2020

M protein was extracted from the cell walls of streptococci by use of both acidic and alkaline buffers. These extracts were further purified by ammonium sulfate fractionation and column chromatography. Both diethylaminoethyl and carboxymethyl celluloses were employed to cover thepH range of 3.0 to 9.0. All of the M proteins isolated were immunologically related, but their physical and chemical properties varied dependent upon thepH range of isolation. Each isolate appeared to be homogeneous on the basis of immunodiffusion analysis, electrophoretic mobility, and ultracentrifugal analysis, but their amino acid analyses differed slightly. Two factors were shared by all isolates: (i) they all reacted with type-specific antisera and (ii) each seemed to havel-lysine as a single N-terminal amino acid.
Temperature-Sensitive Initiation of Chromosome Replication in a Mutant of
Escherichia coli
Authors: Kuempel Peter L.
Published: January 2020

The properties of
Escherichia coli
mutant D2-47LT indicate that it is temperature-sensitive for a protein required for the initiation of chromosome replication. The results of several different experiments are consistent with this hypothesis, and no support was found for the alternate hypotheses tested. Although the strain is usually unable to initiate replication at 42 C, some of the initiation proteins are apparently synthesized at the restrictive temperature. This can cause initiation on partially replicated, but not completed, chromosomes. It appears that the temperature-sensitive protein is required for initiation on completed chromosomes.
Decay of Normal and 5-Fluorouracil-Substituted Messenger Ribonucleic Acid of Alkaline Phosphatase in
Escherichia coli
Authors: Yagil Ezra , Silberstein Nava
Published: January 2020

The decay of alkaline phosphatase messenger ribonucleic acid (mRNA) in
Escherichia coli
was studied in cells sensitized to actinomycin D by ethylenediaminetetra-acetate treatment. It was found that in the wild-type strain (K-10) as well as in a nonsense mutant (S26C200), which is phenotypically reversible by treatment with 5-fluorouracil, mRNA decays with a half-life of 2.0 to 2.5 min. Similarly, in a 3-min pulse of labeled 5-fluorouracil, 70% of the incorporated analogue is contained in the labile RNA fraction decomposing with a half-life of 1.8 min.
Catabolic Activities of
Neisseria meningitidis:
Utilization of Glutamate
Authors: Mallavia Louis P. , Weiss Emilio
Published: January 2020

Glutamate was catabolized at a rapid rate by
Neisseria meningitidis
, group B. Surprisingly, there was a lag of 5 to 30 min in respiration, but not in CO
2
production from C
1
, and an appreciable amount of succinate accumulated. The eventual rapid rate of respiration was not prevented by the addition of chloramphenicol. The lag period was eliminated by combinations of substrates that favored the activity of a glutamate-oxaloacetate transaminase. It is suggested that with glutamate as the sole substrate, the reaction terminated at succinate, required only moderate O
2
uptake, and did not result in the transport of succinate to enzymatic sites. The lag period represented the time required for the accumulation of succinate and its transport to enzymatic sites by energy provided by the metabolism of the remaining glutamate. When the transaminase was operative, on the other hand, successive products of the reaction were immediately placed in contact with enzymatic sites.
Ultrastructure of the Cell Envelope of
Escherichia coli
B After Freeze-Etching
Authors: Nanninga N.
Published: January 2020

The cell envelope of
Escherichia coli
B was investigated with the freeze-etching technique. A considerable gain in visible structural detail over more conventional electron microscopic techniques was obtained. The inner surface of the plasma membrane revealed a smooth surface sparsely studded with particles measuring from 5 to 10 nm in diameter, whereas the outer surface of the plasma membrane showed many more particles of corresponding diameter. The freeze-etched cell wall appeared to be a multilayered structure. The innermost layer could be observed as a profile studded with closely packed elements of about 10 nm in diameter. External to this layer was a smooth surface bordering the outermost cell wall layer. When frozen in the absence of glycerol the outermost surface observed in the cell wall was smooth, but when grown in the presence of glycerol it had a “wavy” appearance with small particles attached to it. The observations support current concepts on the ultrastructure of the enterobacterial cell envelope.
Partial Characterization of the Factor Responsible For Tryptophanless Death in
Bacillus subtilis
Authors: Barlati Sergio , Majerfeld Irene
Published: January 2020

The decline in colony-forming ability observed during tryptophan starvation of
Bacillus subtilis
auxotrophs is a concentration-dependent phenomenon. It does not manifest itself when the initial cell concentration is 10
6
cells/ml or lower. This property has been used to test the killing activity of different fractions of the dying cells. Most of the activity recovered is found in the supernatant fluid of the starved culture. Sensitive and resistant strains can be identified. Active supernatant fluids can only be isolated from tryptophan auxotrophs sensitive to tryptophanless death. Resistant cells neither produce nor respond to the factor, and sensitive cells respond only when deprived of tryptophan. The killing activity is continuously produced and released into the medium at least up to 4 hr after removal of tryptophan from the culture. The killing activity is deoxyribonuclease-, ribonuclease-, and heat-resistant.
In Vivo Suppression of Coding Associated with Bacteriophage-Induced
S
-Adenosylmethionine Hydrolase
Authors: Siersma P. W. , Lederberg S.
Published: January 2020

The methylation of ribosomal and transfer ribonucleic acid (RNA) synthesized after the induction of a hydrolase for
S
-adenosylmethionine by phage T3 infection is reducible to 50% of the methylation of RNA in uninfected cells. Hypomethylated ribosomal RNA is found in 70
S
particles that dissociate in 100 μ
m
Mg
++
to yield only 30
S
and 50
S
subunits. By this criterion, the omitted methyl groups apparently are not required for ribosomal maturation or stability. The rate of production of alkaline phosphatase in a phosphatase amber mutant was examined after phage infection in the presence and in the absence of streptomycin to determine the effect on the translation process consequent to
S
-adenosyl-
l
-methionine (SAM) hydrolase induction. Significant increases in the rates of phosphatase production were found when ultraviolet-inactivated T3 or streptomycin was added. The effects were cumulative when the cells were treated with both bacteriophage and the drug. Ultraviolet-inactivated T7, a phage closely related to T3 but which does not produce the SAM hydrolase, did not enhance the rate of alkaline phosphatase production. We suggest that the production of SAM hydrolase affects the stability of the translation process by the observed hypomethylation or by mechanisms concerning polyamine metabolism.
Physiological and Kinetic Studies with Anthranilate Synthetase of
Bacillus alvei
Authors: Catena Anthony , DeMoss R. D.
Published: January 2020

Anthranilate synthetase from
Bacillus alvei
was partially purified by ammonium sulfate fractionation and was stabilized by glycerol. The reaction mechanism of the enzyme was found to be sequential with respect to substrate, and the enzyme formed a hydroxamic acid in the absence of Mg
++
. The
K
m
for chorismic acid was 1.25 × 10
−4
m
, and the
K
m
for
l
-glutamine was 5.5 × 10
−4
m
. Enzyme activity was inhibited by tryptophan noncompetitively with respect to chorismic acid and uncompetitively with respect to
l
-glutamine. An analysis of the inhibition patterns indicated that tryptophan may act as a dead end inhibitor and bind at the catalytic site. Enzyme activity could be completely inhibited in vitro and in vivo under the appropriate conditions, and enzyme synthesis was sensitive to repression by tryptophan. A sedimentation coefficient of 5.5
S
and an estimated molecular weight of 90,000 were obtained for the enzyme.
Stable Messenger Ribonucleic Acid and Germination ofMyxococcus xanthusMicrocysts
Authors: Ramsey W. Scott , Dworkin Martin
Published: January 2020

We have examined germination, protein synthesis and ribonucleic acid (RNA) synthesis by microcysts of the fruiting myxobacteriumMyxococcus xanthus. The morphological aspects of microcyst formation were completed at about 2 hr after induction had begun. In such microcysts, germination, RNA synthesis, and protein synthesis were inhibited by actinomycin D (Act D). At 6 hr after induction, germination and protein synthesis had become relatively resistant to Act D, whereas RNA synthesis was inhibited by about 95%. Experiments with3H-Act D indicated that the deoxyribonucleic acids of both young and old microcysts bind Act D equally. Resistance of germination to Act D was acquired 4 to 5 hr after induction of microcyst formation, and was due to an Act D-sensitive synthesis at that time. Vegetative cells and microcysts were pulsed with uridine-5-3Hand chased for 60 min; the RNA was extracted and analyzed by means of sucrose density gradient centrifugation and gel electrophoresis. Both microcysts and vegetative cells were found to contain grossly the same types of RNA in the same proportions. RNA pulse-labeled in microcysts was more stable than that in vegetative cells. No particular portions of the microcyst pulse-labeled RNA were selectively stabilized. These data indicate that a stable messenger RNA required for synthesis of germination proteins was synthesized during microcyst formation. This may be the same as the RNA synthesized 4 to 5 hr after initiation of microcyst formation. We suggest that the existence of such stable messenger RNA in microcysts is consistent with the limited biosynthetic activities of such cells.
Gluconate Catabolism in
Rhizobium japonicum
Authors: Keele Bernard B. , Hamilton Pat B. , Elkan Gerald H.
Published: January 2020

Gluconate catabolism in
Rhizobium japonicum
ATCC 10324 was investigated by the radiorespirometric method and by assaying for key enzymes of the major energy-yielding pathways. Specifically labeled gluconate gave the following results for growing cells, with values expressed as per cent
14
CO
2
evolution: C-1 = 93%, C-2 = 57%, C-3 = 30%, C-4 = 70%, C-6 = 39%. The preferential release of
14
CO
2
from C-1 and C-4 indicate that gluconate is degraded primarily by the Entner-Doudoroff pathway but the inequalities between C-1 and C-4 and between C-3 and C-6 indicate that another pathway(s) also participates. The presence of gluconokinase and a system for converting 6-phosphogluconate to pyruvate also indicate a role for the Entner-Doudoroff pathway. The extraordinarily high yield of
14
CO
2
from C-1 labeled gluconate suggests that the other participating pathway is a C-1 decarboxylative pathway. The key enzyme of the pentose phosphate pathway, 6-phosphogluconate dehydrogenase, could not be demonstrated. Specifically labeled 2-ketogluconate and 2,5-diketogluconate were oxidized by gluconate grown cells and gave ratios of C-1 to C-6 of 2.73 and 2.61, respectively. These compare with a ratio of 2.39 obtained with specifically labeled gluconate. Gluconate dehydrogenase, the first enzyme in the ketogluconate pathway found in acetic acid bacteria, was found. Oxidation of specifically labeled pyruvate, acetate, succinate, and glutamate by gluconate-grown cells yielded the preferential rates of
14
CO
2
evolution expected from the operation of the tricarboxylic acid cycle. These data are consistent with the operation of the Entner-Doudoroff pathway and tricarboxylic acid cycle as the primary pathways of gluconate oxidation in
R. japonicum
. An ancillary pathway for the initial breakdown of gluconate would appear to be the ketogluconate pathway which enters the tricarboxylic acid cycle at α-ketoglutarate.
Deoxyribonucleic Acid Base Composition of Lactobacilli Determined by Thermal Denaturation
Authors: Miller A. , Sandine W. E. , Elliker P. R.
Published: January 2020

Moles per cent guanine plus cytosine content of 16 lactobacilli provided three taxonomic groups: I, 32.4 to 38.3% with five species; II, 42.7 to 48.0% with six species; III, 49.0 to 51.9% with five species.
Reassociation of Deoxyribonucleic Acids fromActinoplanesand Other Actinomycetes
Authors: Farina Gandolfina , Bradley S. G.
Published: January 2020

The ability of deoxyribonucleic acid (DNA) isolated from a number of actinomycetes to reassociate with reference DNA fromActinoplanes philippinensisorStreptomyces venezuelaehas been measured. All of the DNA preparations except for those fromNocardia erythropolisandThermomonospora viridiscontained 70 to 73 moles per cent guanine and cytosine. DNA from two species ofActinoplanes, two species ofDactylosporangium, andAmpullariella digitataformed extensive thermally stable duplexes with theActinoplanes philippinensisreference. DNA from streptomycetes formed duplexes with theA. philippinensisreference, but these duplexes possessed low thermal stability. DNA fromN. erythropolisandT. viridisdid not bind significant amounts of this reference DNA. Only DNA fromStreptomyces albus, Streptoverticillium baldaccii, andMicroellobosporia flaveaappreciably bound theStreptomyces venezuelaereference. Our results separate the actinomycetes forming sporangia into two groups: the first group containedActinoplanes, Dactylosporangium, andAmpullariella;the second group containedPlanomonospora, Spirillospora, andStreptosporangium.
Malate Dehydrogenase Mutants in
Escherichia coli
K-12
Authors: Courtright J. B. , Henning Ulf
Published: January 2020

Mutants devoid of malate dehydrogenase activity have been isolated in
Escherichia coli
K-12. They do not possess detectable malate dehydrogenase when grown aerobically or anaerobically on glucose as sole carbon source. All mutants revert spontaneously; a few partial revertants have been found with a malate dehydrogenase exhibiting altered electrophoretic mobility. Therefore, only one such enzyme appears to exist in the strains examined. No evidence could be obtained for the presence of a malate dehydrogenase not linked to nicotinamide adenine dinucleotide. Mutants deficient in both malate dehydrogenase and phosphoenol pyruvate carboxylase activities will grow anaerobically on minimal glucose plus succinate medium; also, malate dehydrogenase mutants do not require succinate for anaerobic growth on glucose. The anaerobic pathway oxaloacetate to succinate or succinate to aspartate appears to be accomplished by aspartase. Malate dehydrogenase is coded for by a locus somewhere relatively near the histidine operon, i.e., a different chromosomal location than that known for other citric acid cycle enzymes.
Mechanisms of Lactose Utilization by Lactic Acid Streptococci: Enzymatic and Genetic Analyses
Authors: McKay L. , Miller A. , Sandine W. E. , Elliker P. R.
Published: January 2020

The apparent instability of β-galactosidase in toluene-treated cells or cell-free extracts of lactic streptococci is explained by the fact that these organisms do not contain the expected enzyme. Instead, various strains of
Streptococcus lactis, S. cremoris
, and
S. diacetilactis
were shown to hydrolyze
o
-nitrophenyl-β-
d
-galactoside-6-phosphate (ONPG-6-P), indicating the presence of a different enzyme. In addition, lactose metabolism in
S. lactis
C
2
F was found to involve enzyme I (EI), enzyme II (EII), factor III (FIII), and a heat-stable protein (HPr) of a phosphoenolpyruvate (PEP)-dependent phosphotransferase system analogous to that of
Staphylococcus aureus
. Mutants of
S. lactis
C
2
F, defective in lactose metabolism, possessed the phenotype lac
−
gal
−
. These strains were unable to accumulate
14
C-thiomethyl-β-
d
-galactoside, to hydrolyze ONPG, or to utilize lactose when grown in lactose or galactose broth. In addition, these mutants contained EI and HPr, but lacked EII, FIII, and the ability to hydrolyze ONPG-6-P. This suggested that the defect was in the phosphorylation step. Lactose-negative mutants of
S. lactis
7962, a strain containing β-galactosidase, could be separated into several classes, which indicated that this organism is not dependent upon the PEP-phosphotransferase system for lactose metabolism.
Deoxyribonucleic Acid Synthesis and Cell Division in alon−Mutant ofEscherichia coli
Authors: Leighton P. M. , Donachie W. D.
Published: January 2020

Thelon−mutants ofEscherichia coliform long filamentous cells after temporary inhibition of deoxyribonucleic acid (DNA) synthesis by ultraviolet irradiation, treatment with nalidixic acid, or thymine starvation. The kinetics of DNA synthesis and cell division after a period of thymine starvation have been compared inlon+andlon−cells. After this treatment, both kinds of cells recover their normal DNA to mass ratio with the same kinetics. In contrast to previous reports, cell division is found to recommence in bothlon+and inlon−cells after such a temporary period of inhibition of DNA synthesis. However, the delay separating the recommencement of DNA synthesis and of cell division is approximately three times as long inlon−as inlon+cells. Low concentrations of penicillin inhibit cell division in bothlon+andlon−cells. In this case, cell division recommences with the same kinetics in both strains after the removal of penicillin. This suggests that different steps in the cell division process are blocked by inhibition of DNA synthesis and by penicillin treatment. Thelon−mutation appears to affect the former of these steps.
Isolation of L-Forms of
Bacillus subtilis
Which Grow in Liquid Medium
Authors: Young Frank E. , Haywood Patricia , Pollock Mary
Published: January 2020

L-forms of
Bacillus subtilis
can be isolated by treatment of the parent strain sequentially with
N
-methyl-
N
′-nitro-
N
-nitrosoguanidine and lysozyme and selection of the surviving protoplasts on semisolid medium containing 2,000 units of penicillin per ml. Some of these clones can be adapted to grow in liquid cultures containing 1.2
m
NaCl. This method will aid in the isolation of cell wall mutants which require hypertonic medium for growth.
Correlation Between Pigment Production and Amino Acid Requirements in
Bacillus subtilis
Authors: Taylor Martha J. , Lawton William D. , Goldberg Ivan D.
Published: January 2020

Several
Bacillus subtilis
W-23 auxotrophs were unable to produce wild-type pigment normally on minimal agars supplemented sufficiently for growth. This offers a reliable means for scoring genotypes.
Identification of the
purI
locus in
Escherichia coli
K-12
Authors: Tritz Gerald J. , Matney Thomas S. , Chandler J. L. R. , Gholson R. K.
Published: January 2020

A genetic locus has been identified in
Escherichia coli
that is analogous to the
purI
locus in
Salmonella
.
Influence of Temperature on Steady-State Growth of Colonies of
Pseudomonas fluorescens
Authors: Johnson M. G. , Palumbo S. A. , Rieck V. T. , Witter L. D.
Published: January 2020

Diameters of surface colonies of
Pseudomonas fluorescens
were observed to increase linearly with time at temperatures from 30 to 0 C.
Feedback Inhibition of
l
-Glutamine
d
-Fructose 6-Phosphate Amidotransferase by Uridine Diphosphate
N
-Acetylglucosamine in
Neurospora crassa
Authors: Endo Akira , Kakiki Kazuo , Misato Tomomasa
Published: January 2020

The enzyme,
l
-glutamine
d
-fructose 6-phosphate amidotransferase (EC 2.6.1.16) of
Neurospora crassa
, which catalyzes the formation of glucosamine 6-phosphate was shown to be subject to feedback inhibition by uridine diphosphate
N
-acetyl-
d
-glucosamine (UDP-GlcNAc). The conclusion is based on the following observations. UDP-GlcNAc, the direct precursor of chitin, did not accumulate in the cell even when its utilization for the synthesis of cell wall chitin was interrupted by the antibiotic polyoxin D, a competitive inhibitor of the chitin synthetase (EC 2.4.1.16). Furthermore, the cellular level of UDP-GlcNAc rose in a short period of time when the amidotransferase was bypassed in vivo by the addition of glucosamine to the growing medium of the fungus. The amidotransferase was purified from
N. crassa
approximately 85-fold. Kinetic studies showed that UDP-GlcNAc was a potent and specific inhibitor of the amidotransferase, and that it did not alter the Michaelis constant for either
l
-glutamine or
d
-fructose 6-phosphate, suggesting that the inhibitor binds at a site on the enzyme distinct from the active site.
Isolation and Serological Characterization of a Cell Wall Antigen ofRothia dentocariosa
Authors: Hammond Benjamin F.
Published: January 2020

A soluble polysaccharide antigen from the cell wall ofRothia dentocariosaATCC 17931 has been isolated, purified and characterized by serological and chemical procedures. The polysaccharide (RPS) was found to be located at the surface of cells grown under diverse environmental conditions, and could be easily detected on cells in pure culture or in clinical samples from humans and experimentally infected hamsters by fluorescent-antibody techniques. Fructose, glucose, galactose, and ribose were the major constituents of RPS. Although purified RPS was not immunogenic in rabbits, it was presumed to be a major antigen of the cell because it could specifically absorb approximately one-third of the antibody nitrogen in antisera prepared against whole cells ofR. dentocariosa. Haptene inhibition studies indicated that fructose was the principal determinant of serological specificity in RPS. This polysaccharide was found to be serologically unique and did not cross-react with the polysaccharides and surface polymers of other oral actinomycetes and filamentous organisms.
Induction of Morphogenesis by Methionine Starvation in
Myxococcus xanthus:
Polyamine Control
Authors: Witkin Steven S. , Rosenberg Eugene
Published: January 2020

The induction of mycrocyst formation by methionine starvation was demonstrated in
Myxococcus xanthus
by several methods. Growing in a defined medium (M
1
),
M. xanthus
had a doubling time of 6.5 hr. Four amino acids—leucine, isoleucine, valine, and glycine—were required for growth under these conditions. When the concentration of several amino acids in the medium was reduced (M
2
), the doubling time increased to 10 to 12 hr, and a requirement for methionine was observed. Methionine starvation led to a slow conversion of the population to microcysts. Under conditions of methionine prototrophy (M
1
), microcyst formation could still be triggered in exponentially growing cells by the addition of either 5 m
m
ethionine or 0.1
m
isoleucine plus 0.1
m
threonine, feedback inhibitors of methionine biosynthesis. Vegetative growth in the absence of methionine was obtained in medium M
2
if the leucine concentration was raised to its level in medium M
1
. Thus, methionine biosynthesis is controlled by the exogenous concentration of the required amino acid, leucine. During an examination of the effects of methionine metabolites on microcyst formation, the involvement of polyamines in morphogenesis was uncovered. Putrescine (0.05
m
) induced the formation of microcysts; spermidine (2 to 5 m
m
) inhibited induction by methionine starvation, ethionine, or high isoleucine-threonine. Spermidine was the only polyamine detected in
M. xanthus
(16.0 μg/10
9
cells). Its concentration decreased by more than 50% shortly after microcyst induction by high isoleucine-threonine. It is postulated that spermidine is an inhibitor of microcyst induction; when spermidine formation is blocked by methionine starvation, morphogenesis is induced.
Acholeplasma axanthum, sp. n.: a New Sterol-Nonrequiring Member of the Mycoplasmatales
Authors: Tully Joseph G. , Razin Shmuel
Published: January 2020

Mycoplasmas recovered from tissue cultures and previously shown to belong to the sterol-nonrequiring group of mycoplasmas have been further characterized. The biological and serological properties of these strains show them to be clearly distinct from
Acholeplasma laidlawii
and
A. granularum
, two species of sterol-nonrequiring mycoplasmas recently reclassified. It is proposed that the newly described mycoplasmas be designated
Acholeplasma axanthum
, sp. n.
Sheathed Cells in Cultures of
Clostridium sporogenes
Authors: Betz John V.
Published: January 2020

Many strains of
Clostridium sporogenes
were shown to contain two types of cells which exhibited strikingly different growth habits. Over 99% of the population of most strains were motile bacilli which occurred singly or in short chains. Infection by any of several
C. sporogenes
bacteriophages lysed most of these cells and revealed a minority population component consisting of cells which grew in extremely long chains. Each chain was surrounded by and contained in a long tubular polysaccharide sheath which was ultrastructurally quite separate and distinct from the cell walls of the enclosed cells. The sheathed cells were identical to “normal” cells of
C. sporogenes
in anaerobiosis, Gram reaction, sporulation, deoxyribonucleic base composition, general morphology, and ultrastructure. They differed from the “normal” cells in having a sheath, in being nonmotile, and in that they were infected by
C. sporogenes
bacteriophages but not usually lysed by them. The sheathed cells appeared spontaneously in cultures cloned from single colonies and were demonstrably present in cultures before bacteriophage infection. Thus, they were not contaminants but were normal, although inconspicuous, growth forms of
C. sporogenes
which were selected but not induced by bacteriophage infection.
Protein Difference Between Competent and Noncompetent Cultures of a Group H
Streptococcus
Authors: Ranhand Jon M. , Theodore Theodore S. , Cole Roger M.
Published: January 2020

Acidified phenol extracts prepared from competent cultures of a group H
Streptococcus
strain Wicky made competent with competence factor derived from cultures of another group H
Streptococcus
, strain Challis, showed a difference in polyacrylamide-gel protein patterns when compared to extracts prepared from noncompetent cultures of strain Wicky. The prominent single protein band difference did not appear when Wicky cells were simultaneously treated with competence factor and chloramphenicol, an inhibitor of the development of competence. Chloramphenicol had no effect on transformation nor the appearance of the “new” protein band when added to fully competent cells. This new protein, which is associated with the appearance of competence, seems to be synthesized as a result of induction by competence factor; its exact role, however, is as yet unknown.
Control of Morphogenesis in
Geodermatophilus
: Ultrastructural Studies
Authors: Ishiguro Edward E. , Wolfe R. S.
Published: January 2020

Geodermatophilus
grows in two major forms, a nonmotile irregularly shaped aggregate of coccoid cells (C-form) and a motile budding rod (R-form). Morphogenesis can be controlled by an unidentified factor in Tryptose which is required for maintenance of the organism in the C-form and for differentiation of the R-form to the C-form. Morphogenetic events occur synchronously in the described system. Ultrastructural studies show that the major difference between C- and R-forms is in cells envelope structure. R-form cell walls consist of two layers, an inner transparent membranous layer (10 to 12.5 nm thick) and an outer dense diffuse layer (7.5 to 10 nm). In addition to these layers, the C-form has a thick fibrous layer (30 nm) over the dense layer. This layer appears to be a cementing substance which holds the coccoid cells together.
Genetic Location in
Escherichia coli
K-12 of the Ultraviolet-Sensitive Mutation
uvrD3
Authors: Siegel Eli C.
Published: January 2020

A host cell reactivation-negative mutation,
uvrD3
, in
Escherichia coli
K-12 is located between
ilv
and
metE
.
Nalidixic Acid-Resistant Auxotrophs of
Escherichia coli
Authors: Helling Robert B. , Adams Barbara Sadoff
Published: January 2020

purB
and
ctr
mutants of
Escherichia coli
are resistant to low levels of nalidixic acid.
Age-Dependent Metabolic Differences in Peripheral Hyphae of
Rhizoctonia solani
Authors: Skowronski Boleslaw S. , Gottlieb David
Published: January 2020

Peripheral hyphae were separated from the remaining thallus of
Rhizoctonia solani
in exponential and stationary phases of growth. The QO
2
in whole cells of peripheral hyphae from young fungal colonies was on the average 2.6 times and the protein content 1.6 times greater than in peripheral hyphae from old fungal colonies. The overall rate of amino acid uptake was less in old than in young fungal colonies. In a polyuridylic acid-polyphenylalanine incorporating system, the two kinds of peripheral hyphae required ribosomes, supernatant fraction, polyuridylic acid, soluble ribonucleic acid, adenosine triphosphate, and pyruvate kinase. The rate of polyphenylalanine synthesis in old fungal colonies was slower than in the young fungal colonies. The ribosomes and supernatant fraction of the young and old fungal colonies were interchangeable and active. The factor responsible for deficient protein synthesis in old fungal colonies appears to be in the soluble fraction of the mycelium.
Characterization of Pyridoxine Auxotrophs ofEscherichia coli: Serine and PdxF Mutants
Authors: Dempsey Walter B. , Itoh Hajime
Published: January 2020

At least six phenotypically distinct classes of mutants ofEscherichia coliwhich require serine or pyridoxine or both can be isolated. Three of the six classes lack 3-phosphoserine-2-oxoglutarate aminotransferase. One of these classes contains WG5, a mutant previously characterized as containing thepdxF5allele. The aminotransferase isolated from this mutant has been compared to that isolated from wild-typeE. coliand found to have apparently normal affinity for pyridoxal 5′-phosphate, but reduced affinity for pyridoxamine 5′-phosphate.
Partial Purification and Characterization of Glycogen Phosphorylase from
Dictyostelium discoideum
Authors: Jones Theodore H. D. , Wright Barbara E.
Published: January 2020

Glycogen phosphorylase was isolated from cells of
Dictyostelium discoideum
in the culmination stage of development and purified 35-fold. The enzyme had a
p
H optimum of 6.9 and contained sulfhydryl groups essential for activity. The
K
m
values for phosphate and glycogen were 3 m
m
and 0.06% (w/v), respectively. No dependence on, or stimulation by, any nucleotide was observed and a wide variety of nucleotides and glycolytic intermediates did not inhibit the enzyme. Nucleotide sugars competitively inhibited the enzyme. Guanosine diphosphoglucose and adenosine diphosphoglucose were the most effective, and uridine diphosphoglucose was the least effective of the nucleotide sugars tested. The specific activity of glycogen phosphorylase increased from about 0.004 unit per mg of protein in aggregating cells to about 0.024 unit per mg in culminating cells, and then decreased during sorocarp formation. This increase in enzyme specific activity during the starvation and aging of the system can account for the increased rate of glycogen degradation during this period of development. Amylase specific activity, measured at
p
H 4.8 and 6.9, varied between 0.005 and 0.013 unit per mg of protein during all stages of development.
Cell Walls of
Pseudomonas
Species Sensitive to Ethylenediaminetetraacetic Acid
Authors: Wilkinson S. G.
Published: January 2020

Cell walls of 12 pseudomonads considered to be sensitive to ethylenediaminetetraacetic acid (EDTA) were prepared and analyzed. The wall of each species contained protein, peptidoglycan, loosely bound lipid, and lipopolysaccharide. The walls of
Pseudomonas stutzeri
and
P. syncyanea
were unusually susceptible to mechanical disintegration. The wall of
P. syncyanea
had an unusually high content of lipid and low contents of protein and peptidoglycan. Except for
P. syncyanea
, all the walls contained less phosphorus than the walls of the highly EDTA-sensitive
P. aeruginosa
and
P. alcaligenes
, but more than the walls of EDTA-resistant pseudomonads. The amino acid compositions of wall proteins were similar for all species. Amino sugars detected were glucosamine, galactosamine, muramic acid, and at least five unidentified components (possibly including fucosamine and quinovosamine). Glucose and rhamnose were the major neutral sugars in most walls. Galactose, mannose, fucose, and ribose were also detected, the last two each in a single species. Except for
P. stutzeri
and
P. syncyanea
, the walls had rather low contents of phospholipids (mainly cardiolipin, phosphatidylethanolamine, and phosphatidylglycerol in all species). An ornithine-containing nonphospholipid was present in all walls, and a hexuronosyldiglyceride was probably present in most walls. The fatty acid compositions of loosely bound lipids were qualitatively similar for all species: saturated C
16
and monoenoic C
16
and C
18
acids were the major components. Except for
P. aureofaciens
, the extraction of phosphorus on treatment of walls with EDTA at
p
H 9.2 was much less than for
P. aeruginosa
and
P. alcaligenes
.
Nalidixic Acid and the Metabolism of
Escherichia coli
Authors: Winshell Elaine B. , Rosenkranz Herbert S.
Published: January 2020

Nalidixic acid (NAL) is bactericidal for
E. coli
B. Synthesis of deoxyribonucleic acid (DNA), ribonucleic acid and protein was necessary to initiate the lethal effect, but only protein synthesis was necessary to sustain it. NAL inhibited DNA synthesis specifically, but this inhibition occurred even under conditions that were not lethal to the bacteria. In contrast to other inhibitors of DNA synthesis, NAL did not cause the solubilization of cellular DNA even when bacteria were exposed to it for 2 hr. A bacterial mutant deficient in DNA polymerase was much more sensitive to the lethal action of NAL than its parent strain. Moreover, inhibition of protein synthesis did not protect this mutant from NAL-induced killing. NAL inhibited neither DNA polymerase, nor thymidine or thymidylate kinases. The data are interpretated as suggesting that NAL altered the structure of DNA or a protein attached to nascent DNA and that this lesion can be partially repaired by DNA polymerase.
Physiology of Sporeforming Bacteria Associated with Insects II. Lipids of Vegetative Cells
Authors: Bulla Lee A. , Bennett Glenn A. , Shotwell Odette L.
Published: January 2020

Lipid composition was studied in two strains each of mid-log phase cells of
Bacillus thuringiensis, B. larvae, B. popilliae, B. alvei
, and
B. lentimorbus
. Total lipids varied from 2.5 to 3.5% of the cell dry weight of
B. thuringiensis
to 4.3 to 5.0% of
B. popilliae
. Phospholipids in the organisms examined ranged from 55 to 79% of total lipids; neutral lipids averaged from 13 to 45%. Common phospholipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and lysophosphatidylethanolamine. 1,2-Diglycerides, methyl esters, free fatty acids, and hydrocarbons were found in all the organisms studied. Branched-chain fatty acids constituted more than 50% of the total fatty acids in
B. thuringiensis, B. larvae, B. popilliae
, and
B. alvei
, whereas, in
B. lentimorbus
, normal-chain acids constituted more than 50%. Anteiso-C
15
(12-methyltetradeconoate) was the most abundant acid (30 to 50%) in
B. alvei, B. larvae, B. popilliae
, and
B. lentimorbus
. In contrast,
B. thuringiensis
contained more iso-C
13
(7%), iso-C
15
(17%), normal-C
16
(24%), and iso-C
17
(18%) than anteiso-C
15
(6%). The distribution of individual fatty acids was similar in the phospholipids and neutral lipids of each organism. However, the total amount of iso, anteiso, and normal isomers differed.
Permanent Alterations of the L-Forms of
Proteus
and
Salmonella
Under Various Conditions
Authors: Dienes Louis
Published: January 2020

L-forms obtained from three strains of
Proteus
and from one strain of
Salmonella
have been kept for 15 to 20 years by weekly or monthly transfers on agar plates containing penicillin. The morphology and growth requirements of these strains have changed. They now grow abundantly on the surface of agar and in broth. The cultures consist of large bodies, small granules, and transitional forms. These organisms are more resistant to distortion and stain more deeply than organisms of the usual L-forms. In broth and to a lesser extent on agar, branching filaments develop, on the ends of which both the large, round organisms and small organisms are produced. The filaments are a transitional stage in the development of the cultures. Usual bacillary forms were not present in the culture and did not appear in successive transfers in the absence of penicillin. Bacilli reappeared on exposure of the L cultures to the influence of a spore-bearing bacillus. A similar transformation of L-forms has also been observed developing within a short time in recently isolated A and B type L cultures of one
Proteus
strain during the process of reversion to the bacterial form. The altered cultures are fixed in a stage of transition between the B type L-form and the regular bacteria.
Isolation of Bacillary and Streptococcal Variants from
Bacterionema matruchotii
Authors: Streckfuss Joseph L. , Smith Willard N.
Published: January 2020

Bacterionema matruchotii
, an oral filamentous organism, dissociated to form unusual flat colonies. Subculture of the flat colonies, composed of diphtheroids, yielded pure cultures of bacillary and streptococcal variants.
Neurospora
Mutant Deficient in Tryptophanyl-Transfer Ribonucleic Acid Synthetase Activity
Authors: Nazario M. , Kinsey John A. , Ahmad Majeed
Published: January 2020

A tryptophan auxotroph of
Neurospora crassa, trp-5
, has been characterized as a mutant with a deficient tryptophanyl-transfer ribonucleic acid (tRNA) synthetase (EC 6.1.1.2) activity. When assayed by tryptophanyl-tRNA formation, extracts of the mutant have less than 5% of the wild-type specific activity. The adenosine triphosphate-pyrophosphate exchange activity is at about half the normal level. In the mutant derepressed levels of anthranilate synthetase and tryptophan synthetase were associated with free tryptophan pools equal to or higher than those found in the wild type. We conclude that a product of the normal tryptophanyl-tRNA synthetase, probably tryptophanyl-tRNA, rather than free tryptophan, participates in the repression of the tryptophan biosynthetic enzymes.