bluuebunny/crossref_metadata_2025 huggingface dataset:
Ribosomal Precursors and Ribonucleic Acid Synthesis in
Escherichia coli
Authors: Matchett William H.
Published: January 2020

Ribosomes and immature ribonucleoprotein particles were isolated from extracts of log-phase cells grown under various conditions. Quantitative measurements were made to determine the relative amounts of immature particles present in the extracts. The results indicate that the steady-state level of ribosomal precursors accounted for essentially a constant fraction of the total ribonucleic acid (RNA) of the cells. For cells with RNA-protein ratios between 0.43 and 0.65, about 1.6% of the total RNA occurred as immature ribonucleoprotein particles. Further, increased levels of immature particles were shown to be correlated with a reduced rate of RNA synthesis in cells recovering from chloramphenicol inhibition. The reduction was found to vary directly with the duration of pretreatment in chloramphenicol and, consequently, with the level of immature particles present in the cells.
Regulation of Nitrate Assimilation and Nitrate Respiration in
Aerobacter aerogenes
Authors: Van 'T Riet J. , Stouthamer A. H. , Planta R. J.
Published: January 2020

The influence of growth conditions on assimilatory and respiratory nitrate reduction in
Aerobacter aerogenes
was studied. The level of nitrate reductase activity in cells, growing in minimal medium with nitrate as the sole nitrogen source, was much lower under aerobic than anaerobic conditions. Further, the enzyme of the aerobic cultures was very sensitive to sonic disintegration, as distinct from the enzyme of anaerobic cultures. When a culture of
A. aerogenes
was shifted from anaerobic growth in minimal medium with nitrate and NH
4
+
to aerobiosis in the same medium, but without NH
4
+
, the production of nitrite stopped instantaneously and the total activity of nitrate reductase decreased sharply. Moreover, there was a lag in growth of about 3 hr after such a shift. After resumption of growth, the total enzymatic activity increased again slowly and simultaneously became gradually sensitive to sonic disintegration. These findings show that oxygen inactivates the anaerobic nitrate reductase and represses its further formation; only after a de novo synthesis of nitrate reductase with an assimilatory function will growth be resumed. The enzyme in aerobic cultures was not significantly inactivated by air, only by pure oxygen. The formation of the assimilatory enzyme complex was repressed, however, by NH
4
+
, under both aerobic and anaerobic conditions. The results indicate that the formation of the assimilatory enzyme complex and that of the respiratory enzyme complex are regulated differently. We suggest that both complexes have a different composition, but that the nitrate reductase in both cases is the same protein.
Comparative Intermediary Metabolism of Vegetative Cells and Microcysts of
Myxococcus xanthus
Authors: Watson Benjamin F. , Dworkin Martin
Published: January 2020

Crude extracts of both vegetative cells and glycerol-induced microcysts of
Myxococcus xanthus
contained the following enzyme activities: phosphofructokinase, phosphoglucoisomerase, fructose-1,6-diphosphatase, fructosediphosphate aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphopyruvate carboxylase, citrate synthase, isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, phosphoglucomutase, and uridine diphosphate glucose pyrophosphorylase. With the exception of isocitrate dehydrogenase, which was present at a fivefold higher concentration in microcysts, all activities in extracts from both types of cells were essentially equal. Hexokinase and pyruvate kinase could not be detected in extracts from either type of cell. Microcysts metabolized acetate at a lower rate than did vegetative cells. Most of this decrease was reflected in a substantial decrease in ability of microcysts to oxidize acetate to CO
2
. In addition, microcysts and vegetative cells showed a different distribution of
14
C-label from incorporated acetate.
Reduction of Nonspecific Background Staining in the Fluorescent Treponemal Antibody-Absorption Test
Authors: Roberts Merritt E. , Miller James N. , Binnings Gerald F.
Published: January 2020

The nonspecific background fluorescence which occurs with the fluorescent treponemal antibody-absorption test for syphilis was found to result from a reaction between serum-treatedTreponema pallidumorganisms and the conjugated antihuman γ-globulin. It was also shown that β-lipoprotein and albumin were the important contributing factors in human serum. Various dilutions of 2.5% trypsin in phosphate-buffered saline specifically reduced background fluorescence under proper test conditions. By employing a trypsin digestion method, a semiautomated procedure utilizing a visual readout has been postulated as feasible.
Respiratory Components of
Aspergillus niger
Mitochondria
Authors: Watson K. , Smith J. E.
Published: January 2020

The respiratory components of tightly coupled mitochondria from the filamentous fungus
Aspergillus niger
were studied. Cytochromes
a
+
a
3
,
b
, and
c
+
c
1
were identified by difference spectra. The cytochrome spectra were qualitatively similar to yeast and rat liver mitochondria. The mitochondria contained, per gram of protein, an average of 2.9 and 7.0 μmoles of ubiquinone and nicotinamide adenine dinucleotide, respectively.
Enrichment of Auxotrophic Mutants of
Aspergillus flavus
by Tritium Suicide
Authors: Donkersloot J. A. , Mateles R. I.
Published: January 2020

A method based on tritium suicide was developed to enrich auxotrophic mutants of
Aspergillus flavus
.
N
-methyl-
N′
-nitro-
N
-nitrosoguanidine (NG) was chosen as a mutagen, since a wide variety of mutations were induced by the action of 0.1% NG on
A. flavus
conidia suspended in phosphate buffer (
p
H 7.0). The decimal reduction time under these conditions was about 30 min, and the surviving population contained 4 to 6% auxotrophs after 1 hr of mutagenesis. This proportion was then increased by tritium suicide of wild-type cells. At a concentration of 1.3 μ
m
,
3
H-leucine was incorporated better than
3
H-proline or
3
H-thymidine into the germinating conidia. With about 20 hr of incubation and a short treatment in a high-speed mixer to disentangle mycelia and conidia, a 5- to 20-fold decrease in the number of survivors resulted from the incorporated
3
H-leucine (5 c/mmole) after 1 week of storage at 5 C. At a 10-fold lower concentration, the uptake of radioactivity and the subsequent suicide rate were much lower. With
3
H-leucine, the proportion of auxotrophs in the surviving population rose from 5 to about 20% during 2 weeks of storage at 5 C. Mutants requiring various intermediates for protein or nucleic acid synthesis or requiring vitamins were isolated. Finally, it was noted that
A. flavus
shows a much higher resistance to tritium suicide than does
Escherichia coli
.
Expression and Localization of
Escherichia coli
Alkaline Phosphatase Synthesized in
Salmonella typhimurium
Cytoplasm
Authors: Schlesinger Milton J. , Olsen Robert
Published: January 2020

The
Escherichia coli
structural gene for alkaline phosphatase was inserted into
Salmonella typhimurium
by episomal transfer in order to determine whether this enzyme would continue to be localized to the periplasmic space of the bacterium even though it was formed in a cell that does not synthesize alkaline phosphatase. The
S. typhimurium
heterogenote synthesized alkaline phosphatase under conditions identical to that observed with
E. coli
. This enzyme appeared to be identical to that synthesized by
E. coli
, and was quantitatively released from the bacterial cell by spheroplast formation with lysozyme. These results showed that localization is not a property unique to the
E. coli
cell and suggested that, in
E. coli
, enzyme location is related to the structure of the protein. Formation of alkaline phosphatase in the
S. typhimurium
heterogenote was repressed in cells growing in a medium with excess inorganic phosphate, even though only one of the three regulatory genes for this enzyme is on the episome. Thus,
S. typhimurium
can supply the products of the other two regulatory genes essential for repression even though this bacterium seems to lack the structural gene for alkaline phosphatase.
Autotrophy in
Nitrosocystis oceanus
Authors: Williams Peter J. leb. , Watson Stanley W.
Published: January 2020

Enzymatic assays of cell-free extracts of the ammonia-oxidizing bacterium
Nitrosocystis oceanus
failed to establish that the biochemical basis of its obligate autotrophy stemmed solely from a metabolic defect. All of the Embden-Meyerhof enzymes except phosphofructokinase, and all of the tricarboxylic acid-cycle enzymes, as well as reduced nicotinamide adenine dinucleotide oxidase, were found in these extracts. A phosphoenolpyruvate-CO
2
-fixing system was also demonstrated. Resting cells incubated with
14
C-
d
-glucose and
14
C-
l
-glutamate and cells grown in the presence of
14
C-labeled glucose, glutamate, pyruvate, and methionine incorporated these compounds into cellular material, but at a level too low to provide the cells' major carbon and energy needs.
Cross Pathway Regulation: Effect of Histidine on the Synthesis and Activity of Enzymes of Aromatic Acid Biosynthesis in
Bacillus subtilis
Authors: Nester Eugene W.
Published: January 2020

l
-Histidine and, to a lesser degree,
l
-phenylalanine at concentrations of 10
−4
m
inhibit the growth of leaky mutants (bradytrophs) of
Bacillus subtilis
that are deficient in the synthesis of
p
-hydroxyphenylpyruvate, the first intermediate specific to tyrosine synthesis. The inhibition can be overcome by growth factor amounts of
l
-tyrosine and
p
-hydroxyphenylpyruvate. Histidine and phenylalanine are capable of inhibiting the synthesis of tyrosine in several ways, and the major physiological effect which results in growth inhibition has not been established. Both
l
-histidine and
l
-phenylalanine inhibit the activity of prephenate dehydrogenase at concentrations about 100-fold higher than the inhibitory concentration of
l
-tyrosine. Histidine also appears to repress the synthesis of prephenate dehydrogenase because a histidine bradytroph growing in histidine-supplemented medium has a twofold lower level of this enzyme than the same cells growing in unsupplemented medium. These same two amino acids also inhibit the growth of a bradytroph deficient in dehydroquinate synthetase, an early enzyme in the pathway of tyrosine, phenylalanine, and tryptophan synthesis. The inhibition is overcome by a combination of tyrosine and phenylalanine. Histidine-resistant derivatives of both the prephenate dehydrogenase and dehydroquinate synthetase-deficient strains, which simultaneously have gained resistance to phenylalanine, have been isolated. Most of these resistant mutants synthesize additional tyrosine compared with the parent strain. One class of resistant mutants excretes tyrosine and has a number of enzymes of aromatic acid synthesis which are no longer repressible by any combination of the aromatic amino acids. Tyrosine inhibits the growth of histidine bradytrophs. Histidine, at growth factor levels, overcomes the inhibition.
Spontaneous and ICR191-A-induced Frameshift Mutations in the
A
Gene of
Escherichia coli
Tryptophan Synthetase
Authors: Berger Hillard , Brammar William J. , Yanofsky Charles
Published: January 2020

Frameshift mutant
trpA21
was isolated after ultraviolet treatment and frameshift mutant
trpA540
after ICR191-A (an acridine derivative) treatment of wild-type
Escherichia coli
K-12. The A proteins of spontaneous and ICR191-A-induced partial revertants of these mutants contained altered amino acid sequences one residue shorter than the comparable sequence in the A protein of wild-type bacteria. The data support the conclusion that ICR191-A causes frameshift mutations. The findings further indicate that both base additions and deletions are elicited by ICR191-A treatment and that mutagenesis by this compound sometimes affects more than one base pair. ICR191-A also weakly reverts some missense mutants. Analyses of the relevant peptides of the purified A protein show single amino acid replacements compatible with single base-pair changes. In addition, we found that some spontaneously revertible ICR191-A- and ultraviolet light-induced frameshift mutants are not further stimulated to revert by exposure to ultraviolet light.
Mode of Action of Colicins of Types E
1
, E
2
, E
3
, and K
Authors: Reeves Peter
Published: January 2020

The effect of colicins on deoxyribonucleic acid and protein synthesis, and also their effect on the ability of T4 phage to replicate in
Escherichia coli
K-12, were studied. Colicins of type K inhibited deoxyribonucleic acid synthesis, protein synthesis, and phage growth. Among colicins of type E, there was an absolute correlation between mode of action and subdivision into types E
1
, E
2
, and E
3
.
Control of Pyrimidine Biosynthesis in
Pseudomonas aeruginosa
Authors: Isaac Jillian H. , Holloway B. W.
Published: January 2020

The pathway of pyrimidine biosynthesis in
Pseudomonas aeruginosa
has been shown to be the same as in other bacteria. Twenty-seven mutants requiring uracil for growth were isolated and the mutant lesions were identified. Mutants lacking either dihydroorotic acid dehydrogenase, orotidine monophosphate pyrophosphorylase, orotidine monophosphate decarboxylase, or aspartic transcarbamylase were isolated; none lacking dihydroorotase were found. By using transduction and conjugation, four genes affecting pyrimidine biosynthetic enzymes have been identified and shown to be unlinked to each other. The linkage of
pyrB
to
met-28
and
ilv-2
was shown by contransduction. Repression by uracil alone or by broth could not be demonstrated for any enzymes of this pathway, in contrast to the situation in
Escherichia coli
and
Serratia marcescens
. In addition, derepression of these enzymes could not be demonstrated. A low level of feedback inhibition of aspartic transcarbamylase was found to occur. It is suggested that the control of such constitutive biosynthetic enzymes in
P. aeruginosa
may be related to the comprehensive metabolic activities of this organism.
Transduction of Various R Factors by Phage P1 inEscherichia coliand by Phage P22 inSalmonella typhimurium
Authors: Watanabe Tsutomu , Furuse Chizuko , Sakaizumi Sachiko
Published: January 2020

R factorsfi+andfi−, with various combinations of drug-resistance markers and isolated from independent sources, were transduced by phage P1kc inEscherichia coliand by phage P22 inSalmonella typhimurium. Usually the entire R factor was transduced by P1kc inE. coli, as indicated by the absence of segregation of the drug-resistance markers from their conjugal transferability. In contrast, the patterns of segregation of the drug-resistance markers and their conjugal transferability differed considerably among various R factors after transduction by P22 inS. typhimurium. Transduction frequencies varied among R factors in both transduction systems.
Geodermatophilus, a New Genus of the Dermatophilaceae (Actinomycetales)
Authors: Luedemann George M.
Published: January 2020

Organisms having a complex life cycle similar to the animal pathogen
Dermatophilus congolensis
have been isolated from soils of the United States. The soil isolates grow readily on agar media producing a black, friable, or sooty colony; in broth, the isolates produce a thick sediment with a clear supernatant fluid and occasionally a black surface pellicle. The generic taxon
Geodermatophilus
is proposed for these soil isolates.
Geodermatophilus
differs morphologically from
Dermatophilus
in thallus shape, ensheathment, and branching, and physiologically in respect to blood hemolysis, casein hydrolysis, carbohydrate utilization, acid production, and media requirements. The type species proposed is
G. obscurus
. Three subspecies are recognized.
Base Composition of Deoxyribonucleic Acid Isolated from Mycobacteria
Authors: Wayne Lawrence G. , Gross Wendy M.
Published: January 2020

Guanine plus cytosine values of deoxyribonucleic acid derived from 30 cultures representing 14 mycobacterial species or varieties are presented. These data provide impressive reasons for maintaining the separation between the genera
Corynebacterium
and
Mycobacterium;
no conclusions can be arrived at from these data with respect to the
Nocardia-Mycobacterium
relationship. A bimodal clustering, in terms of guanine plus cytosine composition, is apparent within the genus
Mycobacterium
. In general, all members of any single phenetic species appear to fit into one or another of these clusters. The phenetic separation of species is, in some cases, confirmed by separation in terms of guanine plus cytosine values. The bimodal separation of guanine plus cytosine values within the genus
Mycobacterium
does not correspond to a division of the species into slow and rapid growers; it thus provides no justification for splitting
Mycobacterium
into two genera, composed of slow and rapid growers. This is not to say that such a split would not be useful, only that these data do not contribute to such a decision. Any further attempts to correlate phenetic classification with properties of mycobacterial deoxyribonucleic acid will require more specific techniques, such as molecular hybridization.
Differentiation of
Streptococcus faecalis
Andrewes and Horder and
Streptococcus faecium
Orla-Jensen Based on the Amino Acid Composition of Their Murein
Authors: Kandler O. , Schleifer K. H. , Dandl R.
Published: January 2020

The amino acid composition of the murein (peptidoglycan) of 75 strains of enterococci was investigated. All strains designated
Streptococcus faecalis
according to their physiological properties contained the lysine-alanine type of murein; all strains classified as
S. faecium
contained the lysine-aspartic acid type of murein.
Pyrogenic Responses to Staphylococcal Enterotoxins A and B in Cats
Authors: Clark Wesley G. , Page John S.
Published: January 2020

Pyrogenic responses, ranging up to 4.8 F, were induced in cats by oral administration of highly purified staphylococcal enterotoxin B in doses from 10 to 100 μg/kg. Fever was a more sensitive indicator of intoxication than was emesis. Highly purified preparations of enterotoxin A, whether administered intravenously (0.01 to 1.0 μg/kg), orally (10 to 25 μg/kg), or into the cerebral ventricles (0.005 to 0.020 μg in 0.20 ml), were also pyrogenic in cats. Tolerance to the pyrogenic activity was produced by repeated intravenous injection of a given dose of enterotoxin A but not by repeated intracerebroventricular injection. Enterotoxin A was more potent than enterotoxin B after intravenous injection in causing both fever and emesis. Cross-tolerance could not be demonstrated between enterotoxin A and enterotoxin B or
Salmonella typhosa
endotoxin. This lack of cross-tolerance plus the inability of large oral doses (100 to 4,700 μg/kg) of endotoxin to cause fever or emesis indicate that the reported responses were attributable to the specific toxins administered and not to contamination by other pyrogens.
Production of and Sensitivity to Colicins Among Serologically Classified Strains of
Escherichia coli
Authors: Vosti Kenneth L.
Published: January 2020

A significant proportion of 242 serologically classified strains of
Escherichia coli
of human origin produced colicins (33%) or were inhibited by one or more of six standard colicins (57%). The most common colicins identified were E1, I, and B; colicins B and V had greatest range of activity. Generally, neither the production of, nor sensitivity to, individual colicins was restricted to strains of a single serogroup. The coexistence of strains of one serogroup that were sensitive to the action of a colicin produced by strains of another serogroup was encountered among 2 of 21 fecal specimens containing strains of multiple serogroups. The production of colicins was not a major determinant in the acquistion of, or subsequent changes in, strains of
E. coli
in the feces of 10 newborn infants.
Characterization of a Human Serum Inhibitor ofClostridium histolyticumProteinase(s)
Authors: Luzzati Alma , Goldlust Marvin B. , Levine Lawrence
Published: January 2020

Normal animal sera inhibit at least oneClostridium histolyticumproteinase. An assay procedure based on immune hemolysis was developed for the estimation of this inhibition. This inhibitory activity occurs in various levels in the sera of different animal species. The highest titers have been obtained with rat sera. The inhibitory activity from human serum was isolated and purified 16- to 27-fold by Sephadex G-200 gel filtration and diethylaminoethyl cellulose or hydroxylapatite chromatography. The properties of the human serum inhibitor of the clostridial proteinase were compared with a trypsin inhibiting factor found in the partially purified preparations. Identical behavior of the two inhibitory factors was observed when measured by heat inactivation, β-mercaptoethanol sensitivity,pH stability, and sucrose gradient centrifugation. The inhibitory factor has an approximate sedimentation coefficient (S20,w) of 17. Goat anti–α-2-macroglobulin specifically precipitated the clostridial proteinase inhibitor from a partially purified preparation.
Possible Mechanisms of Action of an Anti-Pasteurella pestisFactor
Authors: Eisler D. M. , Heckly Robert J.
Published: January 2020

Anti-Pasteurella pestisfactor (APF) inhibited bacterial growth, but there was no evidence that APF from either mouse or guinea pig or selected fatty acids physically disrupted the cell wall. The fatty acids selected were representative of those found in APF. APF inhibited oxidation of β-d-glucose but not oxidation of glucose-6-phosphate, whereas fatty acids inhibited the oxidation of glucose-6-phosphate but not oxidation of β-d-glucose. The oxidation of 6-phosphogluconic acid was inhibited by both APF and free fatty acids. Furthermore, APF and potassium laurate inhibited 6-phosphogluconic dehydrogenase in a cell-free extract ofP. pestisstrain E.V. 76. No evidence of β-d-glucose or glucose-6-phosphate dehydrogenases was found in the cell-free extract. The results suggested that APF and fatty acids may killP. pestisby inactivating 6-phosphogluconic acid dehydrogenase. The effects of these agents on other enzyme systems were not excluded.
Biosynthesis of Arginine in L Cells Infected with Chlamydiae
Authors: Treuhaft Mary W. , Moulder James W.
Published: January 2020

Three members of the genus
Chlamydia
were examined for their ability to synthesize arginine, an ability their L cell (mouse fibroblasts) hosts lacked.
C. psittaci
(strain 6BC) multiplied in arginine-free medium 199 without significant decrease in titer and incroporated
14
C-glutamate and
14
C-ornithine into the arginine fraction of its protein. In arginine-free media,
C. trachomatis
(strain mouse pneumonitis) and
C. psittaci
(strain meningopneumonitis) grew to only 1 to 10% of the titer obtained in arginine-containing media. The decreased ability of these two strains to multiply in arginine-free media was paralleled by a decreased ability of infected host cells to incorporate
14
C-glutamate into protein arginine. These results suggest that chlamydiae either synthesize arginine themselves, or, in some unknown manner, cause their host cells to do so.
Inhibition of Membrane Transport in
Streptococcus faecalis
by Uncouplers of Oxidative Phosphorylation and Its Relationship to Proton Conduction
Authors: Harold F. M. , Baarda J. R.
Published: January 2020

We studied the effect of compounds that uncouple oxidative phosphorylation on membrane function in
Streptoccocus faecalis
, an organism which relies upon glycolysis for the generation of metabolic energy. At low concentrations (ranging from 10
−7
to 10
−4
m
), tetrachlorosalicylanilide, tetramethyldipicrylamine, carbonylcyanide
m
-chlorophenylhydrazone, pentachlorophenol, and dicoumarol strongly inhibited energy-dependent transport of rubidium, phosphate, and certain amino acids. However, these compounds had little effect on the generation of adenosine triphosphate via glycolysis or on its utilization for the synthesis of macromolecules. They also did not seriously inhibit uptake of those monosaccharides and amino acids which do not require concurrent metabolism. It is proposed that the uncouplers interfere with the utilization of metabolic energy for membrane transport. The uncouplers accelerated the translocation of protons across the cytoplasmic membrane. It appears that a proton-impermeable membrane is required for transport, perhaps, because a proton gradient is involved in the coupling of metabolic energy to the translocation of substrates across the membrane.
Ribonucleic Acid and Protein Synthesis in a Mutant of
Bacillus subtilis
Defective in Potassium Retention
Authors: Willis Dawn B. , Ennis Herbert L.
Published: January 2020

A mutant of
Bacillus subtilis
168 (strain 168 KL), which had lost its normal capacity to accumulate K
+
, was used to explore the interrelationship between protein and ribonucleic acid (RNA) synthesis. In contrast to the wild type, the growth rate of strain 168 KL was markedly dependent on the K
+
concentration in the medium. K
+
uptake in the mutant strain was identical to that in the parent, but the mutant was unable to retain and accumulate K
+
. Protein synthesis was markedly dependent on the K
+
concentration in the medium, whereas RNA synthesis was relatively unaffected by changes in the level of K
+
. Most of the RNA synthesized during K
+
depletion was ribosomal RNA; it appeared in crude extracts in the form of ribonucleoproteins particles with sedimentation values between 4
S
and 30
S
. These particles were converted into mature ribosomes when growth was allowed to resume by the addition of K
+
. Simultaneous synthesis of RNA and protein was necessary for the quantitative conversion of the ribonucleoprotein particles into ribosomes. During recovery from K
+
depletion, ribosomal protein was synthesized in preference to the other proteins of the cell.
Diaminopimelate Decarboxylase of Sporulating Bacteria
Authors: Grandgenett Duane P. , Stahly D. P.
Published: January 2020

The
meso
-diaminopimelate (DAP) decarboxylase of
Bacillus licheniformis
, a pyridoxal phosphate-requiring enzyme, was stabilized in vitro by 0.15
m
sodium phosphate buffer (
p
H 7.0) containing 1 m
m
2,3-dimercaptopropan-1-ol, 100 μg of pyridoxal phosphate per ml, and 3 m
m
DAP. When the
meso
-DAP concentration was varied, the enzyme in cell-free extracts of
B. licheniformis
exhibited Michaelis-Menten kinetics. Pyridoxal phosphate was the only pyridoxine derivative which acted as a cofactor. The enzyme was subject to both inhibition and repression by
l
-lysine. The inhibitory effect of lysine was on the
K
m
(
meso
-DAP). A maximum repression of about 20% was obtained. No significant inhibition or activation was produced by cadaverine, dipicolinic acid, phenylalanine, pyruvate, ethylenediamine-tetraacetate, adenosine triphosphate, adenosine diphosphate, or adenosine monophosphate. When
B. licheniformis
was grown in an ammonium lactate-glucose-salts medium, an increase in DAP decarboxylase specific activity occurred during cellular growth with a maximal specific activity at the end of the exponential phase. As soon as growth ceased, the specific activity of the enzyme decreased to approximately one-half of the maximal specific activity and remained at this level thereafter. When
B. cereus
was grown in complex media, there was an increase in DAP decarboxylase specific activity up to the end of the exponential phase. Thereafter, the specific activity decreased to a nondetectable level in 4 hr. Dipicolinic acid synthesis was first detected 15 min later and was essentially complete after an additional 2.5 hr. The significance of the disappearance of DAP decarboxylase in
B. cereus
was discussed with regard to control of dipicolinic acid and spore mucopeptide biosynthesis.
Movement of Carbon from Vegetative Cells to Heterocysts in
Anabaena cylindrica
Authors: Wolk C. Peter
Published: January 2020

Radioactive carbon assimilated by vegetative cells of
Anabaena cylindrica
in the light passed via an intrafilamentous route into heterocysts in the dark. After several hours, label per heterocyst approximated label per vegetative cell. Much of the label entering heterocysts was not available for diffusional exchange back into vegetative cells.
Gelatin-induced Reversion of Protoplasts of
Bacillus subtilis
to the Bacillary Form: Electron-microscopic and Physical Study
Authors: Landman Otto E. , Ryter Antoinette , Fréhel Claude
Published: January 2020

Protoplasts of
Bacillus subtilis
plated on SD medium form L colonies in quantitative yield and propagate in the L form indefinitely. L bodies or protoplasts placed in 25% gelatin medium form bacillary colonies. Details of the reversion of naked bodies to the walled form are reported. In 25% gelatin medium, reversion begins earlier (about 50% reversion in 4 hr) than the multiplication of bacilli. Thus, virtually all the observed bacillary forms are themselves revertants and not the offspring of a few growing clones. The optimal temperature for reversion is 26 C in 25% gelatin. When cells reverting at 26 C are warmed to 40 C for 3 min, reversion is delayed markedly, whereas viability is unaffected. For electron microscopy, a dense protoplast inoculum was placed on a gelatin surface, incubated, and then fixed in situ. There was no multiplication, but crowding delayed reversion markedly. Successive events of reversion are as follows. The loose nucleoid of the protoplasts condenses in response to the gelatin medium and condenses further and further as reversion proceeds. A thin coat of wall develops around the bodies of various sizes and shapes and then increases uniformly in thickness until a wall of normal aspect is formed. Rod-shaped cells grow out from these bodies—sometimes in several directions at once. A few mesosomes begin to appear only after a thin coat of wall has been formed. These are dense, atypical structures compartmented by membranes. They are located at the cell periphery and do not seem to be in contact with the nucleoids. Quantitative estimates showed that only 20 to 25% of revertant cells or cells grown on gelatin contain even a single mesosome. The others have no mesosome at all. Mesosomes thus do not appear to play a significant role in reversion, and normal mesosome functions must presumably be performed elsewhere in the cell in gelatin-grown bacilli. The role of cell wall, its synthesis, and its chemical nature in successive steps in reversion are discussed.
Immunogenicity of Deoxycholate-disrupted Endotoxins
Authors: Jackson Anne L.
Published: January 2020

A comparison of the immunogenicity of sodium deoxycholate-disrupted lipopolysaccharides from
Escherichia coli
cell walls revealed that these fragments, which are nonimmunogenic in the rabbit, have some activity in the mouse. This relationship was independent of the route of immunization and sex, but in both species immunogenicity was restored by dilution or dialysis. Adsorption of disrupted lipopolysaccharides onto bentonite particles or administration with methylated bovine serum albumin and Freund's adjuvant did not appreciably augment activity in vivo. It is postulated that in the mouse the requirements for immunogenicity of these lipopolysaccharides are either less stringent with regard to the three-dimensional structure of the antigen, or that a reaggregation to toxic, native lipopolysaccharides may occur in vivo.
Effect of Sublethal Heat on the Metabolic Activity of
Staphylococcus aureus
Authors: Bluhm Leslie , Ordal Z. John
Published: January 2020

Cells of
Staphylococcus aureus
MF-31 which have been heat-injured at 52 C have an altered metabolic activity. Analyses of whole-cell preparations by means of the Thunberg technique and Warburg manometry showed decreased dehydrogenase activity and oxygen uptake on a variety of substrates. In cell-free extracts prepared from injured cells, it was demonstrated that the specific activity of fructose diphosphate aldolase, lactate dehydrogenase, and butanediol dehydrogenase was less than that of extracts prepared from normal unheated cells. Recovery of the heat-injured cells in a suitable medium supported a return of the dehydrogenase activity and oxygen uptake, but the activity of the enzymes in cell-free extracts prepared from such partially recovered cells did not fully return to the level of normal (unheated) preparations. Addition of chloramphenicol or actinomycin D to the recovery medium, singly or in combination, retarded the return of the normal metabolic activity. Radiorespirometric experiments indicated that the percentage participation of the Embden-Meyerhoff Parnas and hexose monophosphate pathways remained the same for normal and heat-injured cells. The sublethal heat treatment decreased the catabolic capabilities of
S. aureus
and the production of selected end products associated with the metabolism of glucose.
Role of Pyruvate Metabolism in the Growth ofStreptococcus faecalisin the Presence of Propionate
Authors: Kamihara Teijiro
Published: January 2020

The growth ofStreptococcus faecalisis inhibited by propionate, and the inhibition is reversed by lipoic acid or acetate. A study of the role of pyruvate oxidation inS. faecalisshowed that propionate inhibited the lipoic acid-dependent aerobic oxidation of pyruvate in resting cells. Pyruvate dehydrogenation with neotetrazolium as a hydrogen acceptor in cell-free extracts also required lipoic acid and was markedly inhibited by propionyl phosphate as well as sodium propionate. Some lipid substances, such as palmitate, oleate, behenate, and lecithin, had a lipoic acid-replacing effect on growth of the organism. Biotin or bicarbonate promoted the lipoic acid-dependent growth. Acetate-2-14Cadded to the medium was mainly incorporated into the lipid fraction of the cells. Evolution of14CO2from pyruvate-2-14Cwas not observed in resting cells of the organism, even under aerobic conditions. From the above findings, it is concluded that lipid synthesis through pyruvate oxidation plays a very important role in bacterial growth in medium containing propionate.
Association of Toxic Capsule and Cell Wall Mucopeptide with Virulence in
Gaffkya tetragena
Authors: Mageau Richard P. , Roberson Bob S.
Published: January 2020

Nine strains of organisms morphologically and physiologically identified as
Gaffkya tetragena
were obtained from various sources to study their pathogenicity. Initial virulence analysis of all strains by mouse intraperitoneal injection of viable cells revealed that only three strains, recently isolated from and associated with respiratory infections in hospitalized patients, caused death of mice within 48 hr. The
ld
50
for these virulent, encapsulated strains was 1 × 10
7
to 6 × 10
7
viable organisms. To associate virulence with a toxic component, the following fractions were purified from all strains: capsular material, cell walls, mucopeptide preparations from cell walls and whole cells, grouplike material, cytoplasmic material, and culture filtrate with and without added reducing agent. Rabbit and mouse dermal toxicity testing of these fractions revealed that the capsular material, cell walls, and mucopeptide preparations of the virulent strains were toxic. None of the nonvirulent strains contained toxic components, with the exception of one strain which yielded capsular material equal in toxicity to that of the virulent strains. The capsular material induced a soft pustular lesion persisting for approximately 22 days. Cell walls and mucopeptide preparations produced a hard nodular lesion, identical to that produced by autoclaved whole cells, that persisted for 25 to 30 days. One strain may represent a virulence intermediate between the virulent and nonvirulent strains, since it contains toxic capsular material but nontoxic cell wall mucopeptide. The results indicate that the virulence of this organism is associated with toxic capsular material and cell wall mucopeptide.
Development of Competence in Thymine-starved
Bacillus subtilis
with Chromosomes Arrested at the Terminus
Authors: Archer Luis J. , Landman Otto E.
Published: January 2020

Tryptophan- and thymine-requiring cells of
Bacillus subtilis
, emerging from an amino acid starvation treatment which causes arrest of the chromosomes at the terminus, were not transformable. During subsequent incubation in a thymineless medium supplemented with amino acids, the cultures developed competence while retaining chromosome arrest. The competent subpopulation apparently shares the synchronous chromosome arrest of the bulk population. This was shown by different methods. The principal method was marker frequency analysis of the deoxyribonucleic acid extracted from a population enriched for competent cells by a column-chromatographic method. It is concluded that development of the competent state can occur in nondividing cells, and that the presence of a replication fork actively engaged in synthesis of deoxyribonucleic acid is not required for the development of this state.
Mechanism of Action of Nalidixic Acid onEscherichia coliVI. Cell-free Studies
Authors: Boyle James V. , Cook Thomas M. , Goss William A.
Published: January 2020

The effects of nalidixic acid in vitro on deoxyribonucleic acid (DNA)- polymerase (deoxyribonucleosidetriphosphate: DNA deoxynucleotidyltransferase, EC 2.7.7.7), deoxyribonucleotide kinases (ATP: deoxymono- and diphosphate phosphotransferases), and deoxyribosyl transferase (nucleoside: purine deoxyribosyltransferase, EC 2.4.2.6) were examined employing partially purified and crude extracts ofEscherichia coliATCC 11229 andE. coli15TAU. Nalidixic acid had no inhibitory effect on the DNA-polymerase of the wild-type strainE. coliATCC 11229 at concentrations of 1.4 × 10−3to 2.8 × 10−3m. No inhibition of deoxyribonucleotide kinase activity was observed at concentrations of nalidixic acid ranging from 2 × 10−3to 8.6 × 10−3m. Nalidixic acid (0.43 × 10−4to 0.43 × 10−3m) had no inhibitory effect on the deoxyribosyl transferase activity of crude extracts obtained fromE. coliATCC 11229 orE. coli15TAU. Analytical CsCl density gradient centrifugation demonstrated that the DNA obtained after treatment ofE. coli15TAU with nalidixic acid was not cross-linked. These results suggest that the prevention of DNA synthesis in vivo by nalidixic acid is not attributable to inhibition of DNA polymerase, deoxyribonucleotide kinase, deoxyribosyl transferase, or to cross-linking of the DNA of treated cells.
Growth of
Ferrobacillus ferrooxidans
on Organic Matter
Authors: Shafia Fred , Wilkinson Richard F.
Published: January 2020

Following a brief adaptation period to glucose,
Ferrobacillus ferrooxidans
was grown on glucose, mannitol, several other sugars, and a few amino acids in the absence of an oxidizable iron source. Prolonged growth on an organic substrate free from iron rendered the organism obligately organotrophic. The growth rate of the bacterium was greater in heterotrophic culture; the doubling time was approximately 4.5 hr on glucose. The bacterium retained its acidophilic properties during adaptation and growth on glucose and would not grow in neutral or slightly alkaline media. Addition of
p
-aminobenzoic acid was necessary for abundant growth of the cells on glucose. Of the eight strains of Fe
++
-oxidizing bacteria studied, only two strains grew on glucose in a nondialyzed system. The results of manometric studies are discussed with regard to metabolic efficiency of organic matter in this organism.
Distribution of Chromate-labeledBrucella abortusEndoxin in Tolerant Mice
Authors: Leong Daniel , Wilson J. B.
Published: January 2020

Endotoxin tolerance as manifested by a lesser degree of hypoferremia was demonstrated in mice when both pretreatment (10 μg per injection) and challenge (100 μg) does ofBrucella abortusendotoxin were administered intraperitoneally. Qualitative and quantitative studies on the distribution of chromate-labeled endotoxin in normal mice revealed that the endotoxin localized predominately in the liver and hypoferremia could be related to a high uptake of endotoxin by this organ. In tolerant mice, the labeled endotoxin was found mainly in the mesenteric lymph nodes (MLN) with smaller quantities in the blood, spleen, and liver. Experiments with splenectomized mice provided supporting evidence that the liver was the target organ of the hypoferremic response to endotoxin. High localization of endotoxin in the MLN with lower quantities in the blood, livers, and spleens of tolerant mice indicated that tolerance may be the result of a blockage by the MLN, preventing the endotoxin from reaching the liver. This inference was supported by the finding that hypoferremic tolerance did not occur when the hypoferremia-provoking dosage of endotoxin (100 μg) was given intravenously to mice pretreated intraperitoneally. There was less hypoferremia in normal mice injected with a mixture of antiserum and 100 μg of endotoxin than in mice given the same dosage of endotoxin in saline. Distribution studies on endotoxin treated with specific antiserum revealed that the endotoxin localized principally in the MLN, thus preventing most of the endotoxin from reaching the liver, the target organ of the hypoferremic response.
Shear-oriented Microfibrils in the Mucilaginous Investments of Two Motile Oscillatoriacean Blue-Green Algae
Authors: Lamont Hayes C.
Published: January 2020

Trichomes of two oscillatoriacean blue-green algae execute screw-like gliding motion, but the two organisms differ from each other with respect to the screw sense of motion. Electron microscopy of serial longitudinal sections reveals extracellular microfibrils which lie roughly parallel to stream-lines at the surface of each organism. The author proposes that the microfibrils are oriented by shear in a zone just external to the outer unit membrane-like component of the cell wall.
Mesosomes in
Escherichia coli
Authors: Pontefract R. D. , Bergeron G. , Thatcher F. S.
Published: January 2020

When
Escherichia coli
was grown in a synthetic medium and fixed with osmium, sections of the cells revealed clearly defined mesosomes. These mesosomes appeared to develop, in dividing cells, as coiled infoldings of the cytoplasmic membrane. Mature mesosomes formed a link between the cytoplasmic membrane and the nucleus of the cell. The arrangement of the mesosomes in dividing cells led to the hypothesis that division of the nucleus in these cells is accomplished by two separate polar mesosomes. One mesosome is derived from the parent cell and is present at one pole of the daughter cell. The other is freshly synthesized at or near the newly forming pole of the daughter cell. While the old mesosome remains attached to the chromosome received from the parent cell, the newly synthesized mesosome becomes attached to and initiates replication of the new chromosome. As the cell grows and elongates, the two mesosomes, attached to their respective chromosomes move apart, thus effecting nuclear division.
Composite Circular Forms of R Factor Deoxyribonucleic Acid Molecules
Authors: Nisioka Taizo , Mitani Michiko , Clowes Royston
Published: January 2020

Two R factors, one (
R15
) conferring resistance to streptomycin and sulfonamide (SM
r
SU
r
) and the other (
222/R3
) to streptomycin, sulfonamide, and chloramphenicol (SM
r
SU
r
CM
r
), were transferred to a
Proteus mirabilis
strain, and deoxyribonucleic acid (DNA) extracted from these strains was subjected to density-gradient centrifugation.
R15
-DNA formed a single satellite band at a density of 1.709 g cm
−3
. Electron microscopy of samples from this band showed circular molecules of one type, with a contour length of 18 μm (35 × 10
6
daltons).
222/R3
-DNA formed a satellite band with three peaks at densities 1.708, 1.711 and 1.717 g cm
−3
. Electron micrographs revealed circular structures from each band with contour lengths, respectively, of 29 (54 × 10
6
daltons), 36 (68 × 10
6
daltons), and 6 μm (12 × 10
6
daltons). “Supertwisted” forms of several molecular species were found. It is suggested that
222/R3
DNA comprises either a single 36-μm molecule or two individual molecules, 29 and 6 μm in length, and that this may reflect the evolutionary development of R factors.
Growth-physiological Changes in
Escherichia coli
and Other Bacteria During Division Inhibition by 5-Diazouracil
Authors: Previc Edward , Richardson Sheila
Published: January 2020

Diazouracil (DZU) was shown to increase the mean cell volume of several bacterial species. The filaments which it induced with
Escherichia coli
B and
Lactobacillus casei
were examined in section by electron microscopy. In addition to the inhibition of division of
E. coli
by DZU, its effects were studied on mass increase, viability, and deoxyribonucleic acid, ribonucleic acid, and protein synthesis. The dependence of cell age on the division-inhibitory effect of DZU was examined in synchronous cultures. The division-inhibitory effect was not reversed by pantoyllactone, an antagonist of ultraviolet filamentation, or by
l
-tyrosine, which had been reported to antagonize DZU activity.
Deoxyribonucleic Acid Base Composition in Yeasts
Authors: Meyer Sally A. , Phaff H. J.
Published: January 2020

The deoxyribonucleic acid base composition of 15 species of yeasts was determined to obtain further clues to or supporting evidence for their taxonomic position. Species examined belonged to the generaSaccharomyces, Debaryomyces, Lodderomyces, Metschnikowia, andCandida. The range of moles per cent guanine plus cytosine (GC content) for all yeasts examined extended from 34.9 to 48.3%. The sporogenous species and the asporogenous yeasts spanned the range with 36.6 to 48.3% GC and 34.9 to 48% GC, respectively. ThreeSaccharomycesspecies (S. roseiand related species) exhibited significantly higher GC contents thanS. cerevisiae, whereas the fermentative speciesD. globosusrevealed a%GC more aligned to theS. roseigroup than to the nonfermentativeD. hansenii. Similar GC contents were demonstrated byL. elongasporusand its proposed imperfect formC. parapsilosis. The range of GC contents of various strains of threeMetschnikowiaspecies studied was 6.1%, with the type strain ofM. pulcherrimahaving the highest GC content (48.3%) of all of the yeasts examined.
Effects of Colicins E1 and K on Transport Systems
Authors: Fields Kay L. , Luria S. E.
Published: January 2020

The effect of colicins E1 and K on active transport of β-
d
-galactosides and of α-methyl-
d
-glucoside (αMG) by
Escherichia coli
was studied. These colicins strongly inhibited the accumulation of thio-methyl-galactoside (TMG) by bacteria and caused rapid exit of previously accumulated TMG. The inhibition effect was limited to the accumulation phase of galactoside transport; the rate of hydrolysis of
o
-nitrophenyl galactoside, which is dependent on transport of the substrate by the lactose-permease system, was only slightly affected. The accumulation of αMG was highly resistant to inhibition by these colicins under conditions which caused complete suppression of TMG accumulation. These effects of the colicins on transport resemble qualitatively those of sodium azide. The findings were interpreted by assuming that colicins E1 and K inhibit the energy-dependent steps in the accumulation of TMG but do not affect facilitated diffusion of galactosides mediated by the specific transport mechanism. The continued accumulation of αMG was attributed to the fact that this compound is stored by
E. coli
cells as a phosphorylated compound by a phosphoenolpyruvate-dependent transport system rather than by an adenosine triphosphate-linked accumulation mechanism.