bluuebunny/crossref_metadata_2025 huggingface dataset:
Microbial Assimilation of Hydrocarbons: Identification of Phospholipids
Authors: Makula R. A. , Finnerty W. R.
Published: January 2020

The distribution of phospholipids derived from
Micrococcus cerificans
was determined under a variety of nutritive conditions. Cells were grown with hexadecane, heptadecane, or acetate serving as the sole carbon source. Total lipid was isolated by chloroform-methanol extraction, and the phospholipid fraction was isolated by silicic acid column chromatography. The phospholipids were characterized by silicic acid chromatography, by thin-layer chromatography, and by identification of water-soluble products resulting from acid hydrolysis of purified phospholipids. Major phospholipids characterized were phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin. Minor phospholipids were phosphatidylglycerol phosphate and phosphatidylserine. Trace amounts of methylated derivatives of phosphatidylethanolamine were determined by incorporation of
14
C from
14
C-methylmethionine. These experiments demonstrated the presence of phosphatidyl-
N
-methylethanolamine, phosphatidyl-
N,N
′-dimethylethanolamine, and phosphatidylcholine in trace quantities. Pulse labeling with
14
C-serine demonstrated the direct incorporation of serine into phosphatidylserine followed by decarboxylation to phosphatidylethanolamine.
Macroconidial Germination in
Microsporum gypseum
Authors: Leighton T. J. , Stock J. J. , Kelln R. A.
Published: January 2020

Biochemical events which occur during macroconidial germination have been studied in the dermatophyte
Microsporum gypseum
. The specific activity levels of various metabolic enzymes have been assayed during germination time periods. The accumulated levels of several of these enzymes, as a function of exogenous carbohydrate source, have been investigated.
M. gypseum
was found to possess a constitutive glyoxalate shunt, a constitutive glucokinase, a fructose phosphoenolpyruvate transferase, and a mannitol phosphoenolpyruvate transferase. The integration of endogenous reserve utilization during germination is discussed. The purification and properties of an alkaline phosphatase and its possible relationship to sporulation and spore germination also are described.
Induction and Repression of Amidase Enzymes in
Aspergillus nidulans
Authors: Hynes M. J.
Published: January 2020

Aspergillus nidulans
can grow on acetamide as both a carbon and nitrogen source and can also grow on formamide as a nitrogen source. Two distinct enzymes, an acetamidase and a formamidase, are produced. The control of the synthesis of these two enzymes in a wild-type strain was investigated. The formamidase is induced by acetamide and formamide and repressed by ammonia. The acetamidase is induced by formamide and acetamide, repressed by carbon metabolites derived from glucose and acetate, and repressed by ammonia. Repression of the acetamidase by ammonia depends on the carbon source; growth on glucose but not on acetate or acetamide allows repression to occur. The pattern of acetamidase repression is compared with that of histidine catabolic enzymes in various bacteria.
Polar Lipids of
Chromatium
Strain D Grown at Different Light Intensities
Authors: Steiner S. , Burnham J. C. , Conti S. F. , Lester R. L.
Published: January 2020

The total amount and the composition of polar lipids of the photosynthetic bacterium
Chromatium
strain D grown in high (7,500 ft/c) and low (100 ft/c) incident white light were measured. Cells grown with low incident light as compared with cells grown in high incident light contained approximately 3.5 times more chlorophyll and contained significantly more internal membranes (chromatophores) as determined by electron microscopy. Nevertheless, there was approximately 40% more phospholipid in cells grown at 7,500 ft/c than in cells grown with 100 ft/c; the phospholipid composition of the cells was similar under both conditions of growth. These observations lead us to suggest that the organization and perhaps localization of the phospholipids in
Chromatium
may be dependent on the light intensity supplied during growth.
Sporulation of
Bacillus subtilis
in Continuous Culture
Authors: Dawes I. W. , Mandelstam J.
Published: January 2020

Sporulation of
Bacillus subtilis
168 was studied in chemostat cultures. Sporulation occurred at high frequency under limitation of growth by glucose or the nitrogen source in minimal medium, whereas rates of sporulation were low for Mg
2+
, phosphate, citrate, or tryptophan limitation. Sporulation was found at all growth rates tested, and the incidence of spores increased with decrease in growth rate of the culture. Within the range of growth rates up to the maximum obtainable with the defined medium, no threshold effect of growth rate on sporulation was observed. By studying transient states, it was possible to determine the time taken for the appearance of a refractile spore after initiation of a cell to sporulation. Under conditions of glucose limitation, cells were found to be committed to sporulation as soon as they were initiated. In nitrogen-limited cultures, however, a partial relief of nitrogen limitation prevented the development of spores during the first hour after initiation. The results of experiments with multistep changes in dilution rate of a chemostat culture indicate that initiation to sporulation is probably restricted to a particular point in the cell division cycle.
Conjugation in
Escherichia coli
: Interactions Affecting Recombination Frequencies for Markers Situated at the Leading End of the Donor Chromosome
Authors: Walker E. M. , Pittard J.
Published: January 2020

Experiments have been performed to test the validity of a model which relates low recovery of very early donor markers in recombinants to the presence of sex-factor deoxyribonucleic acid at the leading end of donor deoxyribonucleic acid transferred by conjugation. This model has been found to be incorrect. The results obtained do not rule out the possibility that a piece of sex factor is transferred at the leading end, but indicate, however, that if this occurs it is not the cause of the low recovery of a very early donor marker.
Induction of Enterococcal L-Forms by the Action of Lysozyme
Authors: King James R. , Gooder Harry
Published: January 2020

Suspensions of enterococci were treated with lysozyme in the presence of osmotic stabilizers. The resulting osmotically fragile bodies prepared from
Streptococcus faecium
strain F24 and
S. faecalis
strain E1 gave rise to L-forms under optimal osmotic and nutritional conditions for treatment and subsequent growth. The most critical component of the growth medium, to obtain maximum yields, was the nature and concentration of the added salt. The two most effective salts were sodium chloride and ammonium chloride in the range of 2 to 3% (w/v) added to a suitable agar base. Ammonium chloride was more versatile, because it could be used with either sucrose or polyethylene glycol 4000 as the osmotic stabilizer for preparation and dilution of the osmotically fragile bodies. Sodium chloride would not consistently support growth of
S. faecium
F24 as L-forms when polyethylene glycol 4000 was used as the osmotic stabilizer during lysozyme treatment. Time-course studies of concurrent cell wall removal and L-form induction suggested that maximal induction required only cell wall damage rather than complete wall removal. This method for induction of L-forms from a suspension of enterococci is a significant improvement over other presently known methods.
Synchronous Growth of Enteric Bacteria
Authors: Shehata Talaat E. , Marr Allen G.
Published: January 2020

Helmstetter and Cummings devised a technique of synchronization in which cells are implanted on a membrane filter and the membrane is subjected to reverse flow of liquid medium. The cells in the effluent stream have predominantly the characteristics of newborn cells. The advantage of this technique is that the population experiences a minimum of physiological stress; hence, the behavior of the synchronous culture should reflect the normal divisional cycle. The disadvantage is that strains other than
Escherichia coli
B/r cannot be synchronized. We have found that a modification of the method makes it possible to synchronize several strains of
E. coli
, including both male and female strains, as well as
Salmonella typhimurium
LT2. The principal difference in technique is a prolonged period (>400 doublings) of cultivation in glucose minimal medium at 30 C and at low density (<5 × 10
6
cells/ml) prior to implantation. This precaution was taken to insure that the bacterial growth population is in a steady state of balanced growth. From the resulting synchronous growth, the distribution of interdivision times has been computed; these distributions have coefficients of variation in the range 0.18 to 0.22 and are not appreciably skewed.
Transduction and Genetic Homology Between
Pseudomonas
Species
putida
and
aeruginosa
Authors: Chakrabarty A. M. , Gunsalus I. C.
Published: January 2020

Genetic crosses occur by transduction between the species
Pseudomonas aeruginosa
and
P. putida
. The frequency relative to intraspecific transfer is reduced and varies among markers, suggesting that these genomes contain discrete regions of homology and nonhomology.
Thermally Induced Intracellular Alteration of Ribosomal Ribonucleic Acid
Authors: Rosenthal Leonard J. , Iandolo John J.
Published: January 2020

Heating at 55 C causes the intracellular degradation of ribosomes of
Staphylococcus aureus
MF-31. The 30
S
subunit of heated cells appears to be selectively attacked. Analysis of ribonucleic acid (RNA) showed that 16
S
RNA was destroyed and that the secondary structure of 23
S
RNA was altered.
Metabolism of the Glucosyl Diglycerides and Phosphatidylglucose of
Staphylococcus aureus
Authors: Short Steven A. , White David C.
Published: January 2020

A glucose containing lipid, phosphatidylglucose (probably 3-
sn
-phosphatidyl-1′-glucose) and a lipid tentatively identified as phosphatidylethanolamine have been characterized in the lipids of
Staphylococcus aureus
. These lipids together comprise less than 2% of the total phospholipids of exponentially growing
S. aureus
and accumulate to 14% of the total phospholipid in stationary-phase cells. These lipids lost no
32
P when cells grown with H
3
32
PO
4
were transferred to nonradioactive medium during the exponential growth phase. This was in marked contrast to the other phospholipids which lost
32
P rapidly. The loss of
32
P from phosphatidic acid and cardiolipin in exponentially growing cells was biphasic, suggesting heterogeneity of phospholipid phosphate metabolism. The mono- and diglucosyl diglycerides showed a rapid loss of
14
C-glucose during growth in nonradioactive medium but no loss of
14
C from the fatty acids of these lipids. The
14
C in the glucose and fatty acids of the glucosyl diglycerides was derived from glucose.
Regulation of Pectate Lyase Synthesis in
Pseudomonas fluorescens
and
Erwinia carotovora
Authors: Zucker Milton , Hankin Lester
Published: January 2020

Inducible synthesis of extracellular pectate lyase occurs in
Erwinia carotovora
, a bacterial soft-rot pathogen of plants, and, to a lesser extent, in a nonpathogenic isolate of
Pseudomonas fluorescens
. A combination of pectin and a heat-labile factor in fresh potato tissue or acetone powders of the tissue provided the best carbon source for induction. Yields of inducible pectate lyase were much greater than those usually reported. The pathogen, but not the saprophyte, produced a small amount of constitutive enzyme when grown on glucose. The relatively low level or absence of constitutive synthesis in these bacteria did not result from catabolite repression. Attempts were made to relieve any existing catabolite repression by restricting growth through slow feeding of glucose or by growing the organisms on glycerol. These conditions did not significantly alter the differential rate of lyase synthesis compared with changes observed in the presence of inducers. Previous growth history did not affect induction in the pathogen. However,
P. fluorescens
previously cultured on glucose required 10 to 20 generations of growth on inducing medium before appreciable lyase synthesis occurred. Differences between the pathogen and nonpathogen suggest that regulation of pectate lyase synthesis is related to pathogenicity of soft-rot bacteria.
Carbon Monoxide-Reacting Pigment from
Desulfotomaculum nigrificans
and Its Possible Relevance to Sulfite Reduction
Authors: Trudinger P. A.
Published: January 2020

The separation of an autoxidizable brown pigment, P582, from
Desulfotomaculum nigrificans
is described. It reacted with Na
2
S
2
O
4
and was characterized by absorption maxima in the oxidized state at 392, 582, and 700 nm. In the presence of Na
2
S
2
O
4
, P582 formed complexes with CO and, under alkaline conditions, pyridine. There was no reaction with cyanide. The molecular weight of P582 was approximately 145,000, and the purest preparations contained Fe, Zn, and acid-labile sulfide but not Cu, Mo, or Mn. Preparations of P582 catalyzed the reduced methyl viologen (MVH)-linked reduction of sulfite, hydroxylamine, and nitrite but not of sulfate, thiosulfate, or nitrate. Reduced pyridine nucleotides did not substitute for MVH. A major product of the MVH-sulfite reaction was sulfide. CO partially inhibited the enzymatic activities. Sulfite, hydroxylamine, and nitrite and CO caused changes in the spectrum of Na
2
S
2
O
4
-reduced P582. Fe
2+
-chelating reagents reacted with part of the Fe of P582 and caused partial losses of labile sulfide and enzymatic activity. The spectral and CO-reacting properties of P582 were, however, unaffected by chelating agents. The reaction between P582 and chelating agents was stimulated by reducing agents.
Regulation of Glucose Metabolism in
Thiobacillus intermedius
Authors: Matin Abdul , Rittenberg Sydney C.
Published: January 2020

Glucose-yeast extract or glucose-casein hydrolysate-grown
Thiobacillus intermedius
cells, which use glucose for energy generation, possess high specific activities of the Entner-Doudoroff pathway and related enzymes, 6-phosphogluconate dehydrase, 2-keto-3-deoxy-6-phosphogluconate aldolase, glucokinase, and glucose-6-phosphate dehydrogenase, but low activities of enzymes unique to the pentose shunt and Embden-Meyerhof pathways. Although the synthesis of the latter enzymes remains largely unaffected by the growth environment, that of the former is stimulated by glucose. Radiorespirometric measurements demonstrate an early and parallel respiration of glucose carbon atoms one and four in glucose-casein hydrolysate broth. It is concluded that the Entner-Doudoroff pathway performs an energetic role in glucose metabolism by
T. intermedius
with the pentose shunt and Embden-Meyerhof pathways functioning mainly in biosynthesis. The presence of thiosulfate in the growth medium inhibits the synthesis of the Entner-Doudoroff pathway and related enzymes. In addition, both thiosulfate and glucose inhibit the synthesis of the Krebs cycle enzymes, nicotinamide adenine dinucleotide phosphate-linked isocitrate and α-ketoglutarate dehydrogenases. Thus, repression of enzymes is of significance in the adaptation of
T. intermedius
to its nutritional environment. The activity of glucose-6-phosphate dehydrogenase of
T. intermedius
is inhibited by adenosine triphosphate. Such a control could afford the organism a mechanism to regulate the flow of glucose into major energetic and biosynthetic routes.
Cellular Control of the Synthesis and Activity of the Bacterial Luminescent System
Authors: Nealson Kenneth H. , Platt Terry , Hastings J. Woodland
Published: January 2020

In bioluminescent bacteria growing in shake flasks, the enzyme luciferase has been shown to be synthesized in a relatively short burst during the period of exponential growth. The luciferase gene appears to be completely inactive in a freshly inoculated culture; the pulse of preferential luciferase synthesis which occurs later is the consequence of its activation at the level of deoxyribonucleic acid transcription which is attributed to an effect of a “conditioning” of the medium by the growing of cells. Although cells grown in a minimal medium also exhibit a similar burst of synthesis of the luminescent system, the amount of synthesis is quantitatively less, relative to cell mass. Under such conditions, added arginine results in a striking stimulation of bioluminescence. This is attributed to a stimulation of existing patterns of synthesis and not to induction or derepression per se.
Rhodosporidium diobovatum
sp. n., the Perfect Form of an Asporogenous Yeast (
Rhodotorula
sp.)
Authors: Newell Steven Y. , Hunter Ingrid L.
Published: January 2020

New direct evidence of the relationship between the yeast form genus
Rhodotorula
and heterobasidiomycetous fungi is presented, namely, a new species of the heterobasidiomycetous genus
Rhodosporidium
with a rhodotoruloid yeast phase. The new species has the
Rhodosporidium
life cycle but differs significantly from, and is not interfertile with, described species of the genus. It was isolated from marine and estuarine waters of south Florida. The nature of the relationship between the
Rhodosporidium
species and fungi of the order
Ustilaginales
is discussed.
Nucleic Acid Homology in the Genus
Mycobacterium
Authors: Gross Wendy M. , Wayne Lawrence G.
Published: January 2020

Immobilized deoxyribonucleic acid (DNA) preparations from eight species of mycobacteria were reacted with labeled reference DNA from
Mycobacterium tuberculosis
and
M. kansasii
. All mycobacteria showed some degree of homology. Immobilized DNA from
Pseudomonas multivorans
, which has a guanine plus cytosine content within the range established for the mycobacteria, showed no significant binding with either reference system. Relative per cent binding and thermal stability of bound DNA were used as parameters for determining degrees of relatedness among members of the genus. When these relationships were compared with those established by numberical taxonomic methods, a high correlation was found.
Developmental Regulation of Amino Acid Transport in
Neurospora crassa
Authors: Tisdale J. H. , DeBusk A. Gib
Published: January 2020

Conidia of
Neurospora crassa
exhibit an ability to transport various amino acids against a concentration gradient. The conidial transport system has previously been characterized in terms of kinetics, competitions, and genetic control. This study describes the development of a new and highly active transport capability which is elaborated during the early stages of development but prior to evident germination. It has been named “postconidial” transport activity and represents as much as 20-fold greater initial rates as compared to those observed with conidia. Development of the postconidial transport activity requires protein synthesis and can be partially repressed when the substrate amino acid is present during the developmental preincubation period. A mutant has been utilized which exhibits normal conidial but fails to develop normal postconidial transport activity for any amino acid examined. Although temperature optimum and
p
H dependence are similar in conidial and postconidial systems, there is evidence that the new activity is not a simple amplification of an existing capability. This is reflected as a change in competition patterns between particular amino acids as development proceeds.
Analysis of the Multiseptate Potential of
Bacillus subtilis
Authors: Paulton R. J. L.
Published: January 2020

Bacillus subtilis
was grown at 30 C in 15 media which produced generation times of between 200 and 40 min. A correlation was observed between the growth rate and the number of septa per cell. The time between the production of a septum and its involvement in cell division was not related to the growth rate, but, for the 15 populations, had a mean value of 138 min. Multiseptate cells became progressively evident when the organism was grown at rates in excess of a 138-min generation time.
Protoplasmic Organization of Hyphal Tips Among Fungi: Vesicles and Spitzenkörper
Authors: Grove Stanley N. , Bracker Charles E.
Published: January 2020

Hyphal tips of fungi representing
Oömycetes, Zygomycetes, Ascomycetes, Basidiomycetes
, and
Deuteromycetes
were examined by light and electron microscopy and compared with respect to their protoplasmic organization. In all fungi studied, there is a zone at the hyphal apex which is rich in cytoplasmic vesicles but nearly devoid of other cell components. Some vesicle profiles are continuous with the plasma membrane at the apices of these tip-growing cells. The subapical zones of hyphae contain an endomembrane system which includes smooth-surfaced cisternae associated with small clusters of vesicles. The findings are consistent with the hypothesis that vesicles produced by the endomembrane system in the subapical region become concentrated in the apex where they are incorporated at the expanding surface. Septate fungi (
Ascomycetes, Basidiomycetes
, and
Deuteromycetes
) have an apical body (Spitzenkörper) which is associated with growing hyphal tips. In electron micrographs of these fungi, an additional specialized region within the accumulation of apical vesicles is shown for the first time. This region corresponds on the bases of distribution among fungi, location in hyphae, size, shape and boundary characteristics to the Spitzenkörper seen by light microscopy. This structure is not universally associated with tip growth, whereas apical vesicles are widespread among tip-growing systems.
Methods for the Determination of Deoxyribonucleic Acid Homologies in
Streptomyces
Authors: Okanishi M. , Gregory K. F.
Published: January 2020

Variations of the membrane filter technique for deoxyribonucleic acid (DNA) hybridizations were studied with respect to
Streptomyces
species. At the temperatures required for specific hybridization of DNA with the high melting temperature (T
m
) characteristic of
Streptomyces
, large amounts (up to 97%) of filter-bound DNA became eluted, in all reaction mixtures studied, within 21 hr. In most solutions this leaching was increased by the presence of sheared denatured DNA. Incubation of DNA-loaded filters in a solution of 50% formamide containing 6× standard saline citrate, at 48 C for 40 hr, was judged to be the best set of conditions tested based on relatively good retention of immobilized DNA, very low hybridization with unrelated DNA of a similarly high T
m
(from
Sarcina lutea
), and the formation of complexes similar in thermal stability to the native DNA. The expression of results as sheared DNA bound in relation to long-chain DNA retained is recommended when a high concentration of sheared DNA relative to immobilized DNA is used.
Mode of Action of Nitrofurazone
Authors: McCalla D. R. , Reuvers Antoon , Kaiser Christel
Published: January 2020

When
Escherichia coli
strain B/r is exposed to 10 to 20 μg of nitrofurazone per ml, mutants with roughly threefold resistance are obtained. Treatment of these mutants with higher concentrations of nitrofurazone yields strains with six- to seven-fold resistance over strain B/r. Each of these steps toward nitrofurazone resistance is accompanied by loss of soluble nitrofurazone reductase activity. When sensitive bacteria are exposed to labeled nitrofurazone or labeled 2-nitrofuran, a considerable amount of radioactivity becomes bound to the cold trichloroacetic acid-insoluble fraction. Very little activity becomes bound in the mutants with six- to seven-fold resistance; mutants with intermediate resistance show intermediate levels of binding. Partially purified nitrofurazone reductase preparations catalyze the conversion of nitrofurazone to compounds which bind to protein and are not removed by prolonged dialysis against 8
m
urea or by cold acid. Nitrofurazone reduced by xanthine oxidase or electrolytically reduced also yields compounds which react with protein to form stable derivatives.
Growth Inhibition in
Thiobacillus neapolitanus
by Histidine, Methionine, Phenylalanine, and Threonine
Authors: Johnson Corinne L. , Vishniac Wolf
Published: January 2020

Thiobacillus neapolitanus
, a strict chemoautotroph, is sensitive to the addition of 10
−4
m
methionine, histidine, threonine, or phenylalanine to the thiosulfate medium on which it grows. When histidine, threonine, or phenylalanine are added at the time of inoculation, spontaneous mutants tolerant to the three amino acids are selected. These mutants appear to result from a single genetic change; of 18 independently isolated histidine-tolerant mutants, all are also tolerant to phenylalanine and threonine. The uptake of
14
C-phenylalanine into exponentially growing cells of one such mutant is negligible in contrast with the uptake observed in the phenylalanine-sensitive parent. The addition of methionine to the medium slows growth, but spontaneous mutants are not selected. Inhibition of growth by these amino acids is observed only under conditions of amino acid imbalance; the addition of an equimolar mixture of 16 amino acids, in which each component is present at a concentration of 10
−3
m
, causes no inhibition. Histidine and threonine inhibition may be released by equimolar amounts of any one of seven amino acids: serine, alanine, glycine, leucine, valine, tryptophan, or tyrosine; histidine inhibition is also released by isoleucine, and threonine inhibition by methionine. None of the inhibiting amino acids inhibits oxidation of thiosulfate in cell suspensions. A group of hexoses, pentoses, and Krebs cycle intermediates were tested for inhibition of growth or release of inhibition by histidine, phenylalanine, or threonine, but no effects, either inhibition or relief of inhibition, were found.
Phenoloxidase Activity in Organisms Isolated from Lepromatous and Tuberculoid Leprosy
Authors: Beaman LoVelle , Barksdale Lane
Published: January 2020

Anaerobic corynebacteria (propionibacteria),
isolated
in pure culture from the plasma of a case of tuberculoid leprosy and from lepromata of cases of lepromatous leprosy, exhibited phenoloxidase activity such as that shown by Prabhakaran to be associated with leprosy bacilli
harvested
from patients suffering from leprosy. Several corynebacteria, mycobacteria, and nocardias similarly examined did not produce phenoloxidase.
Specific Staining of Wall Mannan in Yeast Cells with Fluorescein-Conjugated Concanavalin A
Authors: Tkacz J. S. , Cybulska E. Barbara , Lampen J. O.
Published: January 2020

A procedure is given for the coupling of fluorescein isothiocyanate to concanavalin A, a protein which specifically combines with a variety of polysaccharides, and for the subsequent isolation of the reactive conjugate. This fluorescent conjugate stains
Saccharomyces cerevisiae
but not
Schizosaccharomyces pombe
or
Rhodotorula glutinis
. The cell walls of the latter two organisms do not contain branched homopolymers of α-linked mannose. Furthermore, the staining of
S. cerevisiae
is competitively inhibited by either unlabeled concanavalin A or methyl-α-
d
-manno-pyranoside. On the basis of this evidence, it is concluded that the staining of
S. cerevisiae
results from the specific interaction of the fluorescein-concanavalin A conjugate with the α-mannan present in the cell wall of this yeast.
Immobilization Effects of Anticell and Antiaxial Filament Sera on
Treponema zuelzerae
Authors: Bharier M. A. , Rittenberg S. C.
Published: January 2020

Rabbit antisera were produced against whole cells and against highly purified axial filaments of
Treponema zuelzerae
. Both types of sera react with axial filaments. Antisera against whole cells immobilize the organism; antisera against axial filaments do not. The immobilizing activity of anticell sera could be neutralized by preabsorption with whole cells but not by preabsorption with axial filaments. Preabsorption with axial filaments did, however, abolish the ability of anticell sera to react with axial filaments. Anticell sera also react with the outer cell envelope; this ability was not affected by preabsorption with axial filaments. The data show that antibody directed at something other than axial filaments causes immobilization of
T. zuelzerae
. The results do not exclude the possibility that the axial filament is the organelle of motility. Titration of the immobilizing activity of anticell sera by adding a constant amount of motile cells to serial dilutions of serum gave two zones of maximum immobilization, one with undiluted serum and one at higher dilutions. For a fixed amount of antiserum, increasing the numbers of cells in the titration almost, but not quite, abolished the zone phenomenon. This phenomenon appears to result from the presence of two kinds of immobilizing antibodies in anticell serum. One of these belongs to the IgG class of immunoglobulins. The other has not been identified but is present in a serum globulin fraction which contains IgM. At intermediate concentrations, the “IgM fraction” inhibits the immobilizing activity of IgG without itself causing immobilization.
Mutant of
Clostridium pasteurianum
That Does Not Fix Nitrogen
Authors: Simon Meredith Ann , Brill Winston J.
Published: January 2020

A stable, non-nitrogen-fixing mutant of
Clostridium pasteurianum
W5 was isolated. The mutant has the same growth rate as the wild type on ammonia nitrogen, but is not able to grow on N
2
. Cell-free extracts of the derepressed mutant are unable to fix nitrogen, or reduce the alternate substrates of nitrogenase such as cyanide, azide, or acetylene. Recombination with wild-type components from a diethylaminoethyl cellulose column indicates that the mutant contains component II, but is lacking component I activity.
Fine Structure of Protoplasts and L-Forms of
Clostridium botulinum
Types A and E
Authors: Brown George W. , Pate J. L. , Sugiyama H.
Published: January 2020

Spherical bodies, that are obtained by adding penicillin and lysozyme to
Clostridium botulinum
types E and A cultures which are growing in an osmotically stabilized medium, are shown to be protoplasts by electron microscopy. The L-forms of these two culture types have morphologically different inclusion bodies.
Nalidixic Acid-Resistant Mutants of
Escherichia coli
Deficient in Isocitrate Dehydrogenase
Authors: Helling Robert B. , Kukora John S.
Published: January 2020

icd
Mutants of
Escherichia coli
K-12, selected for their resistance to nalidixic acid, are deficient in isocitrate dehydrogenase.
Heterotrophic Growth of Blue-Green Algae in Dim Light
Authors: Van Baalen Chase , Hoare Derek S. , Brandt Ellen
Published: January 2020

A unicellular blue-green alga,
Agmenellum quadruplicatum
, and a filamentous blue-green alga,
Lyngbya lagerheimíi
, were grown heterotrophically in dim light with glucose as major source of carbon and possibly energy. The dim-light conditions did not support autotrophic growth. The two blue-green algae appeared to have the same metabolic block, namely an incomplete tricarboxylic acid cycle, as has been found in other obligately phototrophic blue-green algae. Under dim-light conditions, glucose made a greater contribution to cell constituents (amino acids) of
A. quadruplicatum
and
L. lagerheimii
than under high-light conditions.
Biosynthesis of Isoleucine and Valine in
Rhodopseudomonas spheroides
: Regulation of Threonine Deaminase Activity
Authors: Barritt G. J.
Published: January 2020

The activities of threonine deaminase, acetohydroxy acid synthetase, acetohydroxy acid reductoisomerase, dihydroxy acid dehydrase, and transaminase B were detected in cell-free extracts of
Rhodopseudomonas spheroides
. No significant repression or derepression of threonine deaminase activity was observed.
Division Cycle of
Myxococcus xanthus
III. Kinetics of Cell Growth and Protein Synthesis
Authors: Zusman David , Gottlieb Peter , Rosenberg Eugene
Published: January 2020

The kinetics of cell growth and protein synthesis during the division cycle of
Myxococcus xanthus
was determined. The distribution of cell size for both septated and nonseptated bacteria was obtained by direct measurement of the lengths of 8,000 cells. The Collins-Richmond equation was modified to consider bacterial growth in two phases: growth and division. From the derived equation, the growth rate of individual cells was computed as a function of size. Nondividing cells (growth phase) comprised 91% of the population and took up 87% of the time of the division cycle. The absolute and specific growth rates of nondividing cells were observed to increase continually throughout the growth phase; the growth rate of dividing cells could not be determined accurately by this technique because of changes in the geometry of cells between the time of septation and physical separation. The rate of protein synthesis during the division cycle was measured by pulselabeling an exponential-phase culture with radio-active valine or arginine and then preparing the cells for quantitative autoradiography. By measuring the size of individual cells as well as the number of grains, the rate of protein synthesis as a function of cell size was obtained. Nondividing cells showed an increase in both the absolute and specific rates of protein synthesis throughout the growth phase; the specific rate of protein synthesis for dividing cells was low when compared to growthphase cells. Cell growth and protein synthesis are compared to the previously reported kinetics of deoxyribonucleic acid and ribonucleic acid synthesis during the division cycle.
Influence of Chromosome Structure on the Frequency of
tonB trp
Deletions in
Escherichia coli
Authors: Coukell M. B. , Yanofsky C.
Published: January 2020

The frequency of
tonB trp
deletions varies in different strains and substrains of
Escherichia coli
. Studies with chromosomal hybrids constructed by transducing various segments of the
cysB-trp-suIII
region from K-12(Ymel) into K-12(W3110) indicate that the characteristic low deletion frequency of K-12(Ymel) is determined largely by the (genetic) structure of the
trp-suIII
region of the chromosome. Transduction of the
trp
region from K-12(W3110) or K-12(Ymel) into strain B has little effect on the frequency of
tonB trp
deletions in that strain. When
tonB trp
deletions occur at 42 C rather than at 37 C, there is a significant reduction in the frequency of deletions in all strains examined except K-12(Ymel) and hybrids exhibiting a Ymel deletion pattern. The magnitude of this temperature effect in different K-12 strains increases proportionally with the frequency of
tonB trp
deletions at 37 C. At 42 C the frequency of
tonB trp
deletions in all K-12 strains approaches the low frequency observed for Ymel at 37 or 42 C. In contrast, spontaneous deletions in another region of the genome which simultaneously result in resistance to phages T7 and λ and in proline auxotrophy (
tfrA pro
deletions) occur at a constant frequency regardless of growth temperature or the structure of the chromosome in the
trp
region. Two mutants of strain KB30 obtained after treatment with nitrosoguanidine show very low
tonB trp
deletion frequencies. The alterations in both mutants map in the
trp
region of the chromosome. These studies indicate that the structure of the
cysB-trp-suIII
region is responsible for many of the characteristic deletion frequencies observed.
Survey of the Photosynthetic Bacteria for Rhodanese (Thiosulfate: Cyanide Sulfur Transferase) Activity
Authors: Yoch Duane C. , Lindstrom E. S.
Published: January 2020

Rhodanese activity was demonstrated in extracts from all three taxonomic families of photosynthetic bacteria, and this activity appeared to be uncorrelated with thiosulfate metabolism.
Sporulation in
Bacillus brevis:
Studies on Protease and Protein Turnover
Authors: Slapikoff Saul , Spitzer Janet L. , Vaccaro Dennis
Published: January 2020

Bacillus brevis
ATCC 9999 sporulated without the production of extracellular protease when grown and allowed to sporulate on nutrient agar plates containing either azo-albumin, casein, or gelatin. Intracellular protease could not be detected in extracts of cells grown in nutrient broth-salts media. However, approximately one-fifth of the level of protease activity in extracts of
B. subtilis
SB 19 was found in extracts of
B. brevis
ATCC 9999 grown in minimal media. When protein turnover studies were performed by chasing previously incorporated
14
C-
l
-phenylalanine with a large excess of unlabeled phenylalanine, no protein turnover could be detected if the excess phenylalanine was added at T
0
and only a small amount of turnover (1 to 1.6% per hr) was detected if the excess phenylalanine was added at T
2.5-2.7
. This compares with a measured turnover rate of 8.5% per hr in
B. subtilis
SB 19 under similar conditions.
Mode of Action of the Competence-Inducing Factor of
Bacillus stearothermophilus
Authors: Streips Uldis N. , Young Frank E.
Published: January 2020

Development of competence in the noncompetent mutant of
Bacillus stearothermophilus
4S requires a soluble competence-inducing factor (CF). This study describes several observations that define the mechanism of action of this factor. (i) CF interacts with cells, protoplasts, or cytoplasmic membranes in a temperature-dependent reaction; incubation of CF with cells alters the sedimentation properties of the cells. (ii) Association between CF and the cytoplasmic membrane appears to be the first and rate-limiting step in the process of transfection with deoxyribonucleic acid (DNA) from bacteriophage TP-IC. (iii) The membrane-CF complex is capable of removing infectious DNA from the supernatant fraction in vitro. (iv) Twenty phage-resistant mutants are unable to undergo the above reactions. A model is developed in which CF serves as a dynamic mediator of the reaction between the transfecting DNA and the cell surface.
Base Composition of Deoxyribonucleic Acid Isolated from
Athiorhodaceae
Authors: Silver Marvin , Friedman Solomon , Guay Roger , Couture Jaque , Tanguay Robert
Published: January 2020

Guanine plus cytosine content of deoxyribonucleic acid ranged from 60.5 to 65.0% for five
Rhodospirillum
species and from 64.4 to 70.3% for six
Rhodopseudomonas
species. These values were compared to those of two
Hyphomicrobiaceae
and two hydrogen-oxidizing bacteria.
Ultraviolet- and X-Ray-Induced Responses of a Deoxyribonucleic Acid Polymerase-Deficient Mutant of
Escherichia coli
Authors: Paterson M. C. , Boyle J. M. , Setlow R. B.
Published: January 2020

Escherichia coli
K-12,
polAl
−
is a mutant strain whose extracts are deficient in Kornberg deoxyribonucleic acid (DNA) polymerase activity. We have compared the mutant and parental strains on the basis of a number of responses to ultraviolet (UV) and X-irradiation. For both types of radiation, the mutant is more sensitive by approximately the same factor as measured by reduction in colony formation, depression of DNA synthesis, and enhancement of DNA degradation. The rate of repair of X-ray-induced single-strand breaks in the mutant is also slower, as is the repair of breaks after excision repair of UV damage. On the other hand, the mutant has a significant capability to reactivate UV-irradiated λ phage, although it is almost totally deficient in the ability to carry out UV reactivation. The data indicate that the
polAl
mutation leaves the cells with some ability to perform excision and strand-rejoining repair but that an exonuclease, whose identity remains obscure, is the agent responsible for the extensive breakdown of the DNA in
polAl
−
cells after irradiation.
Effect of Iododeoxyuridine upon Conjugation and the Fate of Transferred Deoxyribonucleic Acid in
Escherichia coli
K-12
Authors: Cooper Alan D. , Burgan Murrie W. , White Catherine W. , Herrmann Robert L.
Published: January 2020

The incorporation of 5-iododeoxyuridine (IUdR) into
Escherichia coli
K-12 deoxyribonucleic acid (DNA) has been found to decrease significantly the viability of female strains A288 and JC411
r
but to have only minor effect upon their ability to act as conjugational recipients and to perform recombination after conjugation. In contrast, IUdR incorporation into male strain HfrC appears to interfere with both chromosome transfer and genetic recombination. By using IUdR to densitylabel female DNA, and carrying out large-scale matings with
3
H-thymidine-labeled male cells, we examined the fate of transferred DNA. After a 30-min mating, the T6-sensitive male cells were lysed, and the DNA of the merozygotes and remaining female cells was isolated. Initial centrifugation of this DNA in a CsCl gradient showed that the male and female DNA species were associated. The nature of this association of the parental DNA species was determined by formaldehyde denaturation followed by CsCl centrifugation. Denaturation of DNA isolated immediately after T6 lysis gave a peak of radioactivity banding at the density of light single-stranded DNA. However, denaturation of DNA isolated after T6 lysis and dilution of the cells into fresh medium, exhibited peaks of radioactivity banding at positions corresponding to single-stranded, density-labeled DNA. The results indicate that recombination after conjugation in
E. coli
takes place by a breakage-and-reunion mechanism. The process of recombination can be separated into two stages. In the first stage, the donor and recipient DNA molecules become associated. The second stage consists of the formation of phosphodiester bonds between the donor and recipient segments comprising the recombinant molecule.
Pseudouridylate Synthetase of
Escherichia coli:
a Catabolite-Repressible Enzyme
Authors: Solomon L. R. , Breitman T. R.
Published: January 2020

The growth on pseudouridine of two pyrimidine auxotrophs of
Escherichia coli
(Bu
−
and W63-86) was markedly enhanced when glycerol replaced glucose as a carbon source or when adenosine 3′:5′-cyclic monophosphoric acid was added to medium containing glucose. These results indicated that an enzyme catalyzing a reaction in the pathway of pseudouridine conversion to uracil was sensitive to catabolite repression. The following pathway is proposed for pseudouridine utilization: [Formula: see text] [Formula: see text] Pseudouridylate synthetase was sensitive to catabolite repression in strains Bu
−
and W63-86. In contrast, strains B5RU and W5RU, mutants of Bu
−
and W63-86 which were selected for their ability to grow rapidly on pseudouridine in the presence of glucose, had high levels of pseudouridylate synthetase in the presence of glucose. In the case of B5RU but not W5RU, synthetase activity was greater in cells grown on glycerol or on glucose plus adenosine 3′:5-cyclic monophosphoric acid than on glucose.
Mitomycin C and Temperature Induction of Colicin B in the Absence of Deoxyribonucleic Acid Synthesis
Authors: Hausmann Celma , Clowes Royston C.
Published: January 2020

An
Escherichia coli
K-12 strain and its mutant, temperature-sensitive in deoxyribonucleic acid (DNA) synthesis, were used as hosts for two different ColB factors (ColB3-K166 and ColB4-K98). Induction of either colicin occurred in both hosts in the presence of mitomycin C at 42 C. Induction of the temperature-sensitive colicinogenic hosts also occurred without mitomycin C at 42 C at which temperature no DNA synthesis was observed. Colicin synthesis was a nonlethal event in ColB4-K98
+
cultures, whereas in cultures of ColB3-K166
+
induction led to death of a large fraction of the population.
Presence of Bacteriophage-Like Inhibitory Particles in
Escherichia coli
Authors: Reeve J. N. , Weigand R. A. , Greenawalt J. W.
Published: January 2020

Bacteriophage-like particles were found in the supernatant fluids of
Escherichia coli
O111a and O111:B
4
. Caution is urged in the study of deoxyribonucleic acid synthesis and replication in these strains.
Genetic Order of the Galactose Structural Genes in
Saccharomyces cerevisiae
Authors: Bassel John , Mortimer Robert
Published: January 2020

The galactose structural genes of
Saccharomyces cerevisiae
were ordered by determining the genotypes of mitotic and meiotic recombinants from crosses heterozygous for the three genes. The most probable order is centromere-
gal7-gal10-gal1
. Nonreciprocal recombination was more frequent than reciprocal exchange, and both mitotic and meiotic co-conversions involving mutant sites in all three genes were observed.
Purification and Partial Characterization ofBacillus subtilisFlagellar Hooks
Authors: Dimmitt K. , Simon M. I.
Published: January 2020

A method for preparing bacterial flagellar hook structures is described. The method involves isolating intact flagella from a mutant which makes thermally labile flagellar filaments and heat-treating them to disaggregate the filament preferentially. The resulting hook preparation can be separated and purified by velocity and isopycnic centrifugation. The purified hooks sediment at a relativeSvalue of 77. On acrylamide gel electrophoresis in sodium dodecyl sulfate, they show one major and a number of minor protein bands. The purified hooks can be used to immunize rabbits, and the resulting antiserum is hook-specific. These results support the notion that hooks are composed of a protein that differs from flagellin.
Cold Osmotic Shock in
Saccharomyces cerevisiae
Authors: Patching J. W. , Rose A. H.
Published: January 2020

Saccharomyces cerevisiae
NCYC 366 is susceptible to cold osmotic shock. Exponentially growing cells from batch cultures grown in defined medium at 30 C, after being suspended in 0.8
m
mannitol containing 10 m
m
ethylenedia-minetetraacetic acid and then resuspended in ice-cold 0.5 m
m
MgCl
2
, accumulated the nonmetabolizable solutes
d
-glucosamine-hydrochloride and 2-aminoisobutyrate at slower rates than unshocked cells; shocked cells retained their viability. Storage of unshocked batch-grown cells in buffer at 10 C led to an increase in ability to accumulate glucosamine, and further experiments were confined to cells grown in a chemostat under conditions of glucose limitation, thereby obviating the need for storing cells before use. A study was made of the effect of the different stages in the cold osmotic shock procedure, including the osmotic stress, the chelating agent, and the cold Mg
2+
-containing diluent, on viability and solute-accumulating ability. Growth of shocked cells in defined medium resembled that of unshocked cells; however, in malt extract-yeast extract-glucose-peptone medium, the shocked cells had a longer lag phase of growth and initially grew at a slower rate. Cold osmotic shock caused the release of low-molecular-weight compounds and about 6 to 8% of the cell protein. Neither the cell envelope enzymes, invertase, acid phosphatase and
l
-leucine-β-naphthylamidase, nor the cytoplasmic enzyme, alkaline phosphatase, were released when yeast cells were subjected to cold osmotic shock.
Extracellular Nuclease in the Genus
Lactobacillus
Authors: Miller A. , Sandine W. E. , Elliker P. R.
Published: January 2020

Several species and strains of lactobicilli,
Bacillus coagulans
, and
Sporolactobacillus inulinus
produced detectable amounts of extracellular nuclease which hydrolyzed ribonucleic acid and deoxyribonucleic acid.
Oxidation of Nicotinic Acid by a
Bacillus
Species: Source of Oxygen Atoms for the Hydroxylation of Nicotinic Acid and 6-Hydroxynicotinic Acid
Authors: Hirschberg Rona , Ensign J. C.
Published: January 2020

Three types of evidence are presented to show that the enzymes that hydroxylate nicotinic acid to 2,6-dihydroxynicotinic acid use water as a source of oxygen atoms.
18
O is incorporated into the products from H
2
18
O. Molecular oxygen acts as a terminal electron acceptor, one-half molecule being consumed per molecule of hydroxyl groups incorporated. An external electron acceptor is required for activity in purified preparations.