bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Glucose on the Formation of the Membrane-Bound Electron Transport System in
Haemophilus parainfluenzae
Authors: White David C.
Published: January 2020

The catabolism of glucose by
Haemophilus parainfluenzae
affected the formation of the primary dehydrogenases of the membrane-bound electron transport system. The formation of other components of the respiratory system, 2-demethyl vitamin K
2
, cytochrome
b
1
, cytochrome
c
1
, and the cytochrome oxidases
a
1
,
a
2
, and
o
, is not affected by the catabolism of glucose. The formation of all components of the electron transport system is controlled by the identity and concentration of the terminal electron acceptors present in the growth medium.
Isolation and Characterization of a Recombination-Deficient Hfr Strain
Authors: Hertman Israel M.
Published: January 2020

The isolation of a
rec
−
Hfr strain of
Escherichia coli
K-12 is described. The method used consisted of mating AB2463 F
−
Rec
−
His
−
Lac
−
with P4X6 Hfr Rec
+
His
+
Lac
+
, selecting Rec
−
His
−
Lac
+
recombinants, and searching for Hfr strains. One Hfr
rec
−
strain, no. 12, was used as donor in crosses with Rec
+
and Rec
−
recipients. Crosses with Rec
+
recipients are fertile, and those with Rec
−
recipients are almost infertile, the frequency of recombinants being 10
−2
to 10
−3
that found with Rec
+
recipients. The Rec
−
mutant marker is transfered to and integrated into Rec
+
recipients. Zygotic induction of prophage λ is observed in crosses between two Rec
−
strains. In crosses of F
−
Rec
−
with Hfr Rec
−
, the gradient of integration frequencies for markers progressively more distant from the origin is steeper than in the Rec
+
× Rec
−
or the Rec
−
× Rec
+
crosses.
Induction of Capsular Polysaccharide Synthesis by
p
-Fluorophenylalanine in
Escherichia coli
Wild Type and Strains with Altered Phenylalanyl Soluble Ribonucleic Acid Synthetase
Authors: Kang Soosang , Markovitz Alvin
Published: January 2020

Escherichia coli
K-12 strain AB259 can be induced to form capsular polysaccharide (mucoid clones) by
dl
-
p
-fluorophenylalanine (FPA; 5 × 10
−6
m
on agar plates at 37 C or 8 × 10
−5
m
in liquid medium at 30 C). The change was shown to be phenotypic. An increase in enzymes probably involved in capsular polysaccharide synthesis [phosphomannose isomerase (3.3-fold), uridine diphosphate-
d
-galactose-4-epimerase (2.5-fold), and guanine diphosphate-
l
-fucose synthetase] was demonstrated as a result of growth in FPA. These increases appear sufficient to account for the increased synthesis of capsular polysaccharide due to growth in FPA. FPA-resistant derivatives of strain AB259 were obtained by selecting mutants on FPA-containing agar or by transducing in an altered phenylalanyl soluble ribonucleic acid synthetase that activates FPA poorly. Mucoid clones were formed by these strains only in the presence of 30 to 1,000 times as much FPA. Among these strains, there was a close correlation between incorporation of FPA-
C
14
and induction of capsular polysaccharide synthesis. The results are thus consistent with the following model: FPA is incorporated into the protein product of the
R
1
gene (repressor) and alters it sufficiently to allow derepression of several enzymes.
Early Functional Mutants of Coliphage λ
Authors: Naha P. M.
Published: January 2020

The early functional mutants of λ, belonging to cistrons N, O, and P, are known to be blocked prior to vegetative multiplication of the λ genome. Superinfection of heteroimmune defective lysogens by these mutants failed to elicit the function required for replication of the superinfecting phage. The mutants among themselves also showed poor cooperation on a nonpermissive host. Studies on the effects of different multiplicities of infection for bacterial lysis showed identical responses for mutants of different cistrons.
Keto Acids as Growth-limiting Factors in Autotrophic Growth of
Thiobacillus thiooxidans
Authors: Borichewski R. M.
Published: January 2020

When the strictly autotrophic bacterium
Thiobacillus thiooxidans
was grown on sulfur, keto acids accumulated in the medium until they reached an inhibitory level at which growth ceased. Much greater growth was possible if these substances were continually dialyzed out of the medium.
Mechanism of Fumaric Acid Accumulation in
Rhizopus nigricans
Authors: Romano Antonio H. , Bright Marlene M. , Scott William E.
Published: January 2020

It is doubtful that the glyoxylate bypass plays a significant role in the accumulation of fumaric acid by fungi, as has been postulated. In high glucose media, which favor fumarate production, isocitrate lyase (threo-D
s
isocitrate glyoxylate lyase), which is the key enzyme of the glyoxylate bypass, is strongly repressed. The specific activity of this enzyme remains low as long as glucose is present in the medium, even though fumarate formation proceeds at a high level. In addition, the activity of isocitrate lyase is inhibited by phosphoenolpyruvate, which would be formed from glucose. Alternatively, evidence is presented that bulk accumulation of fumaric acid under aerobic conditions in high glucose media takes place through a C
3
plus C
1
carbon dioxide fixation. CO
2
fixation was measured by the direct incorporation of NaHC
14
O
3
into fumaric acid, and by demonstrating that the specific radioactivity of fumaric acid formed from uniformly labeled
C
14
-glucose was decreased in the presence of nonradioactive carbonate. The extent of decrease in specific radioactivity is in accord with a C
3
plus C
1
CO
2
fixation mechanism.
Factors Influencing the Photodynamic Action of Benzo[
a
]pyrene on
Escherichia coli
Authors: Harrison Arthur P. , Raabe Vivian E.
Published: January 2020

Death of
Escherichia coli
resulted when a buffer suspension was exposed simultaneously to colloidal benzo[
a
]pyrene (BP) and 355-mμ illumination. Neither hydrocarbon nor illumination alone caused death; oxygen had to be present. The survival curve had a shoulder, and then death proceeded exponentially with time. Death rate was independent of temperature between 6 and 32 C. The duration of the shoulder, however, decreased slightly with increase in temperature. The shoulder was not due to delay in BP entering the cell. Death was influenced by the composition of the medium in which the cells were grown prior to illumination. The amount of BP bound to the cells was determined after three ethyl alcoholether extractions. Appreciable binding occurred in the presence of 355-mμ illumination with air, and relatively little binding occurred under nitrogen; very little binding occurred in the dark with nitrogen or air. At the outset, rate of binding under illumination with air was not temperature-dependent, but with time it became strongly temperature-dependent. Binding under illumination with nitrogen was temperature-independent. Bound BP was associated primarily with cell protein. Cells in growth medium resisted death and BP binding. At 21 and 32 C, deoxyribonucleic acid damage occurred during exponential death. No damage was detected at 21 and 32 C in the dark with BP, under illumination in absence of BP, or under illumination with BP in a nitrogen atmosphere.
Carbon Catabolism and Synthesis of Macromolecules During Spore Germination of
Microsporum gypseum
Authors: Barash I. , Conway M. Loretto , Howard D. H.
Published: January 2020

Either
d
- or
l
-leucine (10
−3
m
) and unsaturated long-chain fatty acids such as oleic, linoleic, and arachidonic (10
−4
m
) significantly stimulated macroconidia germination of
Microsporum gypseum
. Saturated long-chain fatty acids did not affect germination, whereas saturated short-chain fatty acids such as caprylic, hexanoic, and butyric were completely inhibitory. Germination was followed by an increase in endogenous respiration and a decrease in dry weight of approximately 5% at 4 hr. Endogenous fatty acids and soluble carbohydrates were utilized significantly during germination. Tritiated leucine, uridine, and thymidine were incorporated respectively into protein, ribonucleic acid (RNA), and deoxyribonucleic acid (DNA) fractions within the first 5 min of germination. Incorporation of oleic-
1-C
14
into RNA and protein was significantly increased after germ tube development. Net synthesis of RNA and protein started prior to germ tube protrusion. Increase in DNA could be detected only later. A significant increase in RNA and protein during the 4th hr of germination was correlated with vegetative development. Inhibition of respiration and incorporation of leucine-
H
3
and uridine-
H
3
into corresponding macromolecules by
dl
-fluorophenylalanine and phenethyl alcohol started before germ tube appearance. Griseofulvin significantly inhibited incorporation of uridine-
H
3
and thymidine-
H
3
, but not of leucine-
H
3
. This inhibition occurred only after initial vegetative development. In contrast to the two other inhibitors, which substantially inhibited germination, griseofulvin only slightly retarded the period of germination and did not affect respiration.
Occurrence of Isocitrate Lyase in a Thermophilic
Bacillus
Species
Authors: Daron Harlow H.
Published: January 2020

A thermophilic, sporeforming bacterium has been isolated from soil on a medium containing acetate as a carbon source. This organism is similar to
Bacillus stearothermophilus
in most respects but differs in its inability to hydrolyze starch. Isocitrate lyase is present in cell-free extracts of organisms grown in a medium with acetate as a carbon source. The specific activity was 400 times lower in extracts of organisms utilizing glucose as a carbon source. With crude extracts, enzyme activity was strongly stimulated by Mg
++
, but cysteine and ethylenediaminetetraacetate had little effect. It appeared to be more heat-stable than the pure isocitrate lyase from
Pseudomonas indigofera
.
Immunological Studies on Dermatophytes I. Serological Reactivities of Neutral Polysaccharides with Rabbit Antiserum to
Microsporum quinckeanum
Authors: Grappel Sarah F. , Blank F. , Bishop C. T.
Published: January 2020

Antiserum produced in the rabbit to autoclaved mycelial suspensions of
Microsporum quinckeanum
reacted with three neutral polysaccharides isolated from each of five species of dermatophytes,
M. quinckeanum, Trichophyton granulosum, T. interdigitale, T. rubrum
, and
T. schönleinii
. The serological reactivities of these polysaccharides, grouped as galactomannans I, galactomannans II, and glucans, were compared by qualitative precipitation analyses in gel and quantitative complement-fixation analyses. Significant differences were found among the glucans and galactomannans II but not among the galactomannans I of these species.
Regulation of Extracellular Protease Production in
Bacillus cereus
Authors: Levisohn Sharon , Aronson Arthur I.
Published: January 2020

Both sporulation and protease production can be inhibited by growing
Bacillus cereus
T in a medium containing a high concentration of a mixture of amino acids. Mutants selected for the ability to sporulate in this inhibitory medium were found to produce high levels of protease in the normal and inhibitory media. Comparison of the mutant and wild-type enzymes by gel electrophoresis and heat inactivation suggested that they were identical. One of the mutants proved to be a purine-requiring auxotroph. Reversion to prototrophy resulted in the loss of the capacity to sporulate in the inhibitory medium and loss of the ability to produce large amounts of protease. Mutants capable of producing high levels of protease and of sporulating in the inhibitory medium were also found when selecting for a purine, pyrimidine, or lysine requirement or for the capacity to sporulate in the presence of a high concentration of glucose. Protease production could be considerably delayed in the purine auxotrophs or completely inhibited in the pyrimidine auxotrophs by growing the cells in a medium containing the inhibitory mixture of amino acids plus hypoxanthine for the former or a pyrimidine for the latter. The fact that a variety of metabolic alterations could lead to excessive protease production suggested that a common catabolic or biosynthetic intermediate was involved in the control of the production of this enzyme(s).
Regulation of Glutamine Synthetase II. Patterns of Feedback Inhibition in Microorganisms
Authors: Hubbard Jerry S. , Stadtman E. R.
Published: January 2020

The feedback inhibition of glutamine synthetase was investigated by use of partially purified enzyme preparations from
Salmonella typhimurium, Micrococcus sodonensis, Pseudomonas fluorescens, Bacillus cereus, Bacillus licheniformis, Clostridium pasteurianum, Rhodospirillum rubrum, Neurospora crassa, Candida utilis
, and
Chlorella pyrenoidosa
. Inhibition analyses indicated that the enzyme of each organism can be effectively regulated with mixtures of end products from the diverse pathways of glutamine metabolism. When tested individually, tryptophan, histidine, alanine, glycine, glutamine, 5′-adenylate (AMP), cytidine-5′-triphosphate, carbamyl phosphate, and glucosamine-6-phosphate gave limited inhibition. In most cases, the inhibitors were independent in their action, and cumulative degrees of inhibition were obtained with mixtures of these end products. In contrast, with the glutamine synthetases of the two
Bacillus
species, the simultaneous presence of AMP and histidine (or AMP and glutamine) gave inhibition greater than the sum of the amounts of inhibition caused by either inhibitor alone. Also, alanine and carbamyl phosphate acted synergistically to inhibit the enzyme from
N. crassa
. The remarkable similarity in the overall patterns of end-product inhibition observed with the enzymes from different sources indicates that these diverse organisms have evolved comparable mechanisms for the regulation of glutamine metabolism. Nevertheless, the enzymes from different sources do differ significantly in their physical and catalytic properties, as was demonstrated by dissimilarities in their purification behaviors, specificity for nucleotide substrate, ability to catalyze the glutamyl transfer reaction, and ability to utilize Mn
++
and Mg
++
as activators for the biosynthetic reaction.
Physiology of Rickettsiae VI. Host-independent Synthesis of Polyribonucleotides byCoxiella burnetii
Authors: Jones Fred , Paretsky D.
Published: January 2020

Preparations of purified and disrupted suspensions ofCoxiella burnetiiare able to incorporate ribonucleotides into polymers in the presence of adenosine, guanosine, cytidine, and uridine triphosphates. Nucleotide incorporation requires the presence of all four ribonucleoside triphosphates. The reaction is enhanced by the addition of phosphoenolpyruvate and pyruvic kinase, and exogenous deoxyribonucleic acid, and is inhibited by deoxyribonuclease and actinomycin D. Incorporation is maximal betweenpH 7.0 and 8.0, and at 37 C. The synthesized polymer is relatively insensitive to deoxyribonuclease and is sensitive to ribonuclease and dilute alkaline hydrolysis. The data indicate the presence of an autonomous deoxyribonucleic acid-dependent ribonucleic acid polymerase in the rickettsial agent.
Indentification and Localization of the Fatty Acids in
Haemophilus parainfluenzae
Authors: White David C. , Cox Richard H.
Published: January 2020

Haemophilus parainfluenzae
was capable of synthesizing 22 fatty acids. These fatty acids were equivalent to 4% of the bacterial dry weight. These fatty acids were localized in the membrane-wall complex, which contained the respiratory pigments, the quinone, and the phospholipids. The fatty acids which could be extracted with organic solvents comprised 86% of the total fatty acids of the cell. These fatty acids were distributed as 98% in the phospholipids and 1.9% in the neutral lipids, of which 0.5% were free fatty acids. Palmitic, palmitoleic, oleic, and vaccenic acids comprised 72% of the total fatty acids and were found almost exclusively in the phospholipids. The phospholipids also contained the cyclopropane fatty acids. The neutral lipids contained significant proportions of the odd-numbered branched and straight-chain fatty acids. The principal free fatty acids were
n
-dodecanoic and pentadecenoic acids. The nonextractable wall complex contained 14% of the total fatty acids. These wall fatty acids were rendered soluble only after saponification. The wall fraction contained all of the β-hydroxymyristic acid and most of the myristoleic and pentadecenoic acids. The significance of the distribution of fatty acids between nonesterified, neutral lipid, phospholipid, and nonextractible wall remains to be determined.
Histochemical Localization of Phosphatases inMycoplasma gallisepticum
Authors: Munkres Marilyn , Wachtel Allen
Published: January 2020

Histochemical studies of adenosine triphosphatase and acid phosphatase activity were performed onMycoplasma gallisepticum. The adenosine triphosphatase activity appears to be localized in the bleb and infrableb regions exclusively and is associated with the cell membrane; acid phosphatase activity is localized in the infrableb region and does not appear to be membrane-associated. These findings are consistent with data from biochemical studies ofMycoplasmacell fractions but, unlike them, reveal that adenosine triphosphatase activity is restricted to a particular part of the cell membrane.
The Cell Wall ofRickettsia mooseriI. Morphology and Chemical Composition
Authors: Wood William H. , Wisseman Charles L.
Published: January 2020

Cell walls prepared by mechanically disrupting intactRickettsia mooseri(R. typhi) were examined in an electron microscope and analyzed chemically. Electron micrographs of metal-shadowed and negatively stained rickettsial cell walls revealed no significant differences, except for smaller size, from bacterial cell walls prepared in a similar manner. The chemical composition was complex, and resembled that of gram-negative bacterial cell walls more closely than that of gram-positive bacterial cell walls.R. moosericell walls contained the sugars, glucose, galactose, and glucuronic acid, the amino sugars, glucosamine, and muramic acid, and at least 15 amino acids. Diaminopimelic acid, a compound hitherto found only in bacteria and blue-green algae, was demonstrated in rickettsiae for the first time. Teichoic acids were not detected. The compounds identified accounted for about 70% of the dry weight of the cell walls.
Chemical, Biological, and Structural Properties of StableProteusL Forms and Their Parent Bacteria
Authors: Weibull C. , Bickel W. D. , Haskins W. T. , Milner K. C. , Ribi E.
Published: January 2020

ProteusL forms were disrupted by osmotic shock, and the sedimentable material present in the homogenate was further fragmented in a Sorvall pressure cell. The pressure cell was also used for disrupting normalProteuscells. The homogenates obtained were fractionated by differential centrifugation. Purified endotoxins were isolated from the major fractions by phenol extraction. Material extracted with phenol from the membrane fraction of the L forms was about as toxic and pyrogenic on a weight basis as the typical enterobacterial endotoxins isolated from cell walls of normal bacteria. The yield of extract from L forms was about one-third of that from an equal weight of normal bacteria. No differences in the gross chemical composition of the phenol extracts from the L forms and the normal cells could be ascertained. A close serological relationship existed between extracts obtained from two L forms and their respective parent bacteria, but no such relationship was found in the case of the third L form studied and its parent bacterium. Diaminopimelic acid was not detected in the membranes of the L forms, but these membranes contained most of the succinic dehydrogenase of the organisms. Only small amounts of this enzyme were present in the wall fraction of normal bacteria. The data obtained suggest that precursors of theProteusendotoxins are formed either in the soluble protoplasm of normal cells and L forms or at sites on the membrane from which they are readily liberated into the protoplasm, whereas the final steps of the synthesis of these toxins take place at the cytoplasmic membrane. In normal cells, much endotoxin is transported to and concentrated in the walls.
Clostridium
Spores with Ribbon-like Appendages
Authors: Rode L. J. , Crawford Margaret A. , Williams M. Glenn
Published: January 2020

Spores of
Clostridium
sp. N1 are characterized by numerous broad ribbon-like appendages attached to one end. The appendages are two to three times the length of the spore and, at their maximal dimension, may be two-thirds the width of the spore. They are attached to the spore body by a common trunk which is continuous with the outer spore coat. Each appendage is a multilayered structure and is enclosed in an amorphous material. Details of spore and appendage formation are described, and appendage ultrastructural features are presented. The function of the appendages is not known.
Influence of Thorotrast Blockade and Acute Renal Artery Ligation on Disapperance of Staphylococcal Enterotoxin B from Blood
Authors: Rapoport Morton I. , Hodoval Leland F. , Beisel William R.
Published: January 2020

The protein toxin staphylococcal enterotoxin B (SEB) produces a clinical syndrome somewhat similar to that of gram-negative endotoxins. Our studies indicate a further similarity to endotoxin in that SEB is rapidly cleared from the plasma of monkeys. However, data reported herein show that an effective Thorotrast blockade of the reticuloendothelial system (RES) does not produce a significant change in the rapid disappearance kinetics of SEB. This observation contrasts with what is known regarding endotoxin clearance. Furthermore, other data reported herein indicate that acute bilateral renal artery ligation produces a profound delay in SEB clearance from plasma. A possible mechanism for renal degradation of SEB is theorized. The RES may play a less important role in the clearance of SEB. This finding contrasts with the demonstrated importance of the RES in clearance and detoxification of gram-negative endotoxin.
Antigenic Relationships of 14 Treponemes Demonstrated by Immunofluorescence
Authors: Meyer Patricia E. , Hunter Elizabeth F.
Published: January 2020

Immunofluorescence was used as an aid in the antigenic grouping of 14 cultivable treponemes. Antisera were prepared versus each treponemal strain, and the antiglobulins were conjugated with fluorescein isothiocyanate. A common antigen-antibody system, detected in the strains studied, was removed by absorption of each conjugate with Reiter orBorrelia vincentiitreponemes. Thus, five categories based on shared group-specific antigens were revealed. Serogroup I: Reiter, English Reiter, Kazan, Kazan numbers 2, 4, 5, and 8. Serogroup II: Nichols and Noguchi. Serogroup III: three oral treponemes, MRB, FM, and N-39. Serogroup IV:B. vincentii. Serogroup V:Treponema zuelzerae. The five serogroups apparently are related by an immunofluorescent common antigen.
Relation of Infection to Tissue Temperature in Mice Infected with
Mycobacterium marinum and Mycobacterium leprae
Authors: Shepard Charles C. , Habas Janet A.
Published: January 2020

Intravenous and footpad infections with
Mycobacterium marinum
and footpad infections with
M. leprae
were compared in the following mouse strains: A/He, BALB/C, CBA, C3H, C57BL, C57L, DBA, 101, and CFW. The results varied a great deal according to mouse strain used. Intravenous injection of high doses of
M. marinum
resulted in deaths after 28 days of 100% of strain A/He, and none of strain 101; 27 days after injection, the feet and noses of all strain CBA mice, but few of the C57BL, 101, or CFW mice, were involved. Injection of a small dose of
M. marinum
into the footpad produced visible disease in 5 days in all of the C57BL and 101 mice, but in not more than 60% of the A/He, DBA, and CFW mice; the average amount of swelling at 17 days varied from 4.40 mm in strain C57L to 0.92 in strain 101. After footpad injection of
M. leprae
, the average plateau harvests varied from 1.3 × 10
7
acid-fast bacteria in strain CBA to 6.5 × 10
5
in strain C57L. The infections in CBA mice extended from the site of inoculation throughout the foot. The temperature was measured rectally, in the footpad, and in the tail. Analysis of all the results revealed little correlation among the three types of infection. There was a strong negative correlation between the tail temperature and the death rate after intravenous injection of
M. marinum
, and a strong positive correlation between footpad temperature and plateau harvest of
M. leprae
.
Development of Resistance to Novobiocin, Tetracycline, and a Novobiocin-Tetracycline Combination in
Staphylococcus aureus
Populations
Authors: Vavra James J.
Published: January 2020

The antibiotic sensitivity of the individual organisms of a bacterial population was determined to study the comparative rates of development of resistance of
Staphylococcus aureus
to novobiocin, tetracycline, and to a combination of these antibiotics. Serial subculture of
S. aureus
with the combination of novobiocin-tetracycline (N-T 2.5:1; the ratio in serum of patients dosed with Panalba) showed a significant retardation of resistance outgrowth compared with subculture in the presence of the antibiotics individually. Increase in organisms resistant to novobiocin seen after one N-T subculture was related to the “concentration gap” between novobiocin and tetracycline. Two additional subcultures with N-T caused little or no increase in organisms resistant to novobiocin, tetracycline, or to the combination. The data suggest that the retardation of further development of resistance was the result of tetracycline inhibition of novobiocin-resistant strains and vice versa.
Fate of Thymine-containing Dimers in the Deoxyribonucleic Acid of Ultraviolet-irradiated
Bacillus subtilis
Authors: Shuster Robert C.
Published: January 2020

The fate of ultraviolet-induced, thymine-containing dimers in the deoxyribonucleic acid (DNA) of
Bacillus subtilis
was investigated in both the wild type (UV
R
) and an ultraviolet light-sensitive (UV
S
) mutant. During incubation in the dark, dimers were excised from the DNA of the UV
R
B. subtilis
, but remained in the DNA of the UV
S
mutant. About 40% of the excised dimers recovered in the wild type were in the acid-soluble fraction; the remainder were in the incubation medium. A UV
S
mutant of
Escherichia coli
K-12, shown previously to be defective in dimer excision, was irradiated with ultraviolet light and incubated under visible light for 3 hr. About 65% of thymine-containing photoproducts were removed from the DNA. These photoproducts were not recovered in the acid-soluble fraction. In comparison, the UV
S
mutant of
B. subtilis
lost only 13% of such photoproducts from DNA when exposed to light under the same conditions.
Effects of Valine on Protein Synthesis and Turnover in
Pseudomonas saccharophila
under “Nongratuitous” Inducing Conditions
Authors: Young H. L. , Klein H. P.
Published: January 2020

Under “nongratuitous” inducing conditions, in
Pseudomonas saccharophila
,
d
-and
l
-valine and
l
-isoleucine inhibit net protein synthesis. At a concentration of 0.5 μmole or greater of valine per mg of bacterial protein, net protein synthesis declined approximately 70%. The inhibitory effect of valine is proportional to the exogenous valine concentration. Studies of
14
C amino acid incorporation and
14
C amino acid release from prelabeled cells indicate that valine stimulates protein turnover.
Metabolic Activity of the Trench Fever Rickettsia,Rickettsia quintana
Authors: Huang Kun-Yen
Published: January 2020

A study of the metabolic activity ofRickettsia quintanawas carried out by conventional Warburg and radioisotope techniques with intact cells harvested while growing in the fluid counterpart of the medium of Vinson and Fuller. Like other rickettsiae,R. quintanadid not utilize glucose, but did metabolize glutamate and glutamine. Unlike typhus rickettsiae,R. quintanadid not require a diluent high in K+for metabolic activity, and it utilized glutamine more efficiently than glutamate. In typical experiments, this microorganism produced 1.6 to 2.0 μmoles of CO2from glutamine per mg of rickettsial protein per hr at 37 C, while consuming 1.5 to 1.7 μmoles of O2.R. quintanaalso utilized, in descending order, succinate, α-ketoglutarate, glutamate, pyruvate, and citrate; the first-named substrate was utilized more rapidly than glutamine.R. quintana, like typhus rickettsiae, has a glutamate-oxaloacetate transaminase because aspartate was isolated, by means of thin-layer chromatography, as one of the end products of the utilization of glutamine. When the microorganisms were incubated with glutamine-14Cand unlabeled intermediates of the citric acid cycle, labeled dicarboxylic acids of the cycle were recovered. Labeled tricarboxylic acids, however, were not recovered, possibly because of cellular impermeability to the corresponding unlabeled intermediates. In the case ofcis-aconitate, it was shown that this substrate interfered with the uptake of glutamine. These observations are believed to provide convincing evidence that glutamine is utilized through the citric acid cycle and thatR. quintana, with the differences noted, resembles other rickettsiae.
14
CO
2
Fixation, Glutamate Labeling, and the Krebs Cycle in Ribose-grown
Hydrogenomonas facilis
Authors: McFadden Bruce A. , Kuehn Glenn D. , Homann H. Robert
Published: January 2020

Exposure of ribose-grown
Hydrogenomonas facilis
to
14
CO
2
for 6 to 12 sec during ribose oxidation resulted in labeling of a number of compounds, three of which were glutamate, phosphoglycerate, and pyruvate. Phosphoglycerate and pyruvate were labeled almost exclusively in C
1
, suggesting operation of the reductive pentose phosphate cycle. Glutamate was labeled initially to the extent of 90% in C
1
and 10% in C
5
, and this was followed by a concentration of radioisotope in C
5
. All of the enzymes of the tricarboxylic acid cycle were detectable in ribose-grown cells, and, in general, specific activities were similar to those found in yeast extract-grown cells. Reduced nicotinamide adenine dinucleotide oxidase, aconitase, and the dehydrogenases for pyruvate, α-ketoglutarate, and succinate appeared to be of particulate origin. In addition to enzymes of the tricarboxylic acid cycle, an acetyl coenzyme A-stimulated phosphoenolpyruvate carboxylase was found, as was isocitrate lyase. Possible participation of these catalysts in glutamate synthesis is discussed.
Regulation of Autotrophic and Heterotrophic Carbon Dioxide Fixation in
Hydrogenomonas facilis
Authors: McFadden Bruce A. , Tu Chang-Chu L.
Published: January 2020

After growth on various carbon sources, sonic extracts of
Hydrogenomonas facilis
contained ribulosediphosphate (RuDP) carboxylase and phosphoribulokinase (Ru5-P kinase). After very short sonic treatment, a reductive adenosine triphosphate (ATP)-dependent incorporation of
14
CO
2
was also detectable. Reduced nicotinamide adenine dinucleotide (NADH
2
) served as reductant 30-fold more effectively than reduced nicotinamide adenine dinucleotide phosphate (NADPH
2
). Adenosine 5′-phosphate (AMP) and adenosine 5′-pyrophosphate (ADP) inhibited Ru5-P kinase and NADH
2
-, ATP-dependent CO
2
fixation. The levels and duration of CO
2
fixation suggested that it is a cyclic process. The requirement of reduced pyridine nucleotide and ATP and the sensitivity of fixation to AMP and ADP support the conjecture that it occurs via the Calvin cycle. After thorough study of variables affecting catalysis, specific activities (millimicromoles of substrate disappearing per milligram of protein) at 30 C were determined for RuDP carboxylase (C), Ru5-P kinase (K) and ATP-, NADH
2
- dependent CO
2
fixation (CO
2
F) after growth autotrophically on fructose, glucose, ribose, glutamate, lactate, succinate, and acetate. Values for these growth modes were, respectively—for C: 67.3, 51.1, 51.4, 24.6, 2.05, 10.2, 2.25, 1.4; for K: 24.7, 24.0, 23.2, 14.2, 12.8, 12.9, 13.4, 2.8; and for CO
2
F: 4.54, 4.83, 3.10, 2.87, 0.85, 1.51, 0.24, 0.41. The qualitative parallel between values for RuDP carboxylase and CO
2
fixation suggests that one major control point in fixation is the step catalyzed by RuDP carboxylase.
Regulation of Glutamate Dehydrogenases During Morphogenesis of
Schizophyllum commune
Authors: Dennen David W. , Niederpruem Donald J.
Published: January 2020

The specific activities of two glutamate dehydrogenases (GDH), one requiring nicotinamide adenine dinucleotide (NAD) and the other specific for nicotinamide adenine dinucleotide phosphate (NADP), varied during growth of
Schizophyllum commune
as a function of the stage of the life cycle and the exogenous nitrogen source. During basidiospore germination on either glucose-NH
3
or glucose-glutamate medium, NADP-GDH increased six- to eightfold in specific activity, whereas NAD-GDH was depressed. During dikaryotic mycelial growth on either nitrogen source, the two GDH increased in a 1:1 ratio, whereas, during homokaryotic mycelial growth on glucose-NH
3
, NADP-GDH activity was depressed and NAD-GDH increased six- to eightfold. Homokaryotic mycelium cultured on glucose-glutamate medium yielded high NADP-GDH activities and normal NAD-GDH activities. Intracellular NH
3
concentration and NADP-GDH activities were inversely related during spore germination and homokaryotic mycelium growth, whereas guanosine-5′-triphosphate (GTP) and
l
-glutamine specifically inhibited NAD- and NADP-GDH respectively in vitro. GTP inhibition was shown in extracts from cells at all stages of the life cycle. Basidiospore germling extracts contained an NADP-GDH essentially resistant to
l
-glutamine inhibition.
Characterization and Stability of Ribosomes from Mesophilic and Thermophilic Bacteria
Authors: Stenesh J. , Yang C.
Published: January 2020

Ribosomes were isolated from three mesophilic and three thermophilic strains of
Bacillus
. The ribosomes consisted of about 55% protein and 45% ribonucleic acid. Average ratios for the absorbance at 260/235 and 260/280 mμ were 1.77 and 1.92 for the mesophiles and 1.63 and 1.84 for the thermophiles. Ultracentrifugation revealed mainly components with sedimentation coefficients of about 30, 50, 70, 100, and 120
S
. All the preparations were shown to contain a ribonuclease which, in the presence of ethylenediaminetetraacetic acid, led to ribosome breakdown as measured by the increase in acid-soluble nucleotides. The stability of the ribosomes from the thermophiles was consistently greater than that of the ribosomes from the mesophiles. After 5 hr at 37 C, the breakdown was about 80% for the ribosomes from the mesophiles and 55 to 70% for those from the thermophiles. At 60 C, the ribosomes from the mesophiles were broken down slightly more and at a faster rate than those from the thermophiles. At temperatures above 60 C, the breakdown was again more pronounced for the ribosomes from the mesophiles.
Permeability Properties of
Rickettsia mooseri
Authors: Myers W. F. , Provost P. J. , Wisseman C. L.
Published: January 2020

The passive permeability properties of
Rickettsia mooseri
to both inorganic and organic solutes have been examined. Visual observations by phase-contrast microscopy of rickettsiae in macerated yolk sacs taken directly from heavily infected eggs revealed plasmolysis with hypertonic NaCl and KCl as well as with sucrose solutions. In contrast, similar visual studies of rickettsiae which had been subjected to freezing or to a purification process, or both, were plasmolyzed by hypertonic sucrose but
not
by hypertonic NaCl and KCl. These primary observations were extended to a variety of solutes and were placed on a quantitative basis by use of optical density and radioisotope dilution methods. Intracellular Na
+
and K
+
concentrations in processed rickettsiae, measured by flame photometry, closely paralleled the concentration of these ions in the suspending medium. It was concluded that
R. mooseri
appears to possess an osmotically active, functional, and structural membrane distinct from the cell wall, located at the surface of a structure analogous to the bacterial protoplast. In the intact organism, this membrane is passively impermeable to sucrose, NaCl, and KCl. However, altered permeability properties, especially to inorganic electrolytes, may be expected in rickettsiae which have been stored in the frozen state and subjected to a lengthy purification process.
Glucose-induced Release of Amino Acids from
Saccharomyces carlsbergensis
by Action on the Cytoplasmic Membrane
Authors: Lewis M. J. , Stephanopoulos D.
Published: January 2020

When washed yeast cells grown under appropriate conditions were suspended in glucose solution there was a sudden release of α-amino nitrogen into the medium. This released material was of low molecular weight, and its composition was closely similar to that of the intracellular free amino acid pool. During the leakage of amino acids, the yeast did not efficiently absorb labeled amino acids added to the test medium, despite the rapid uptake and metabolism of glucose. Uptake of a labeled amino acid and reabsorption of the released α-amino nitrogen occurred almost simultaneously. When these yeast cells were exposed to glucose in the presence of calcium ions, leakage was strongly inhibited. Butanol under the same conditions increased glucose-induced leakage of cell contents. The adenosine triphosphatase activity of intact yeast cells exposed to glucose was greater than that of cells exposed to water. Yeast cells treated with glucose prior to equilibration with sorbose exhibited less ability to retain the sorbose when washed at 0 C than did cells pretreated with water. It was concluded that glucose-induced leakage of amino acids was the result of two factors acting together. These were (i) a change in membrane permeability associated with glucose uptake, and (ii) a temporary shortage of energy for amino acid uptake or retention.
Virulence of
Escherichia coli
Serotypes for Mice
Authors: Jacks Thomas M. , Glantz Paul J.
Published: January 2020

A study was undertaken to determine whether virulence in mice could be used to assess the pathogenicity of a variety of
Escherichia coli
serotypes. Sixty-one
E. coli
strains isolated from animals, poultry, or humans were serotyped to determine their O, K, and H antigens, and were administered to mice via the intraperitoneal route with and without a mucin adjuvant. The
ld
50
dose was then determined for each serotype. The results indicated that the source of the serotype may be associated with virulence for mice. Serotypes isolated from nonenteric, systemic sources showed a greater virulence for mice inoculated intraperitoneally than did the enteric and the nonenteric, nonsystemic (localized) isolates. It was observed that not all serotypes belonging to a specific serogroup were virulent for mice and that the presence or absence of a K antigen had no effect on the virulence of strains of one serotype.
Ultraviolet-sensitive Targets in the Enzyme-synthesizing Apparatus ofEscherichia coli
Authors: Pardee Arthur B. , Prestidge Louise S.
Published: January 2020

Inhibition by ultraviolet light of β-galactosidase and alkaline phosphatase synthesis was investigated in both ultraviolet (UV)-sensitive and UV-resistant (wild-type)Escherichia coli, with the objective of determining the sensitivity of various targets. Kinetics of enzyme formation by unmated bacteria and in mating systems, in which the donor provided the specific genetic material and the recipient the cytoplasm, permit the following conclusions regarding the sensitivity of various targets. Catabolite repression resulting from UV damage causes most of the inhibition of β-galactosidase formation. When it is largely eliminated by a step-down in nutrition, the principal target in UV-sensitive bacteria appears to be the structural gene (lacZ+), but damage to the cytoplasm is also important. Transitory inhibition by inactivation of messenger ribonucleic acid is also observed. In wild-type bacteria, repair reduces the importance of lesions in deoxyribonucleic acid sufficiently that cytoplasmic damage appears to be at least as important. Repair occurs within 10 min, as shown by recovery of enzyme-synthesizing ability. Caffeine and proflavine prevent recovery. Newly mated bacteria respond to irradiation very differently than do unmated bacteria. The β-galactosidase or alkaline phosphatase structural gene (lacZ+orphoP+) is much more inhibited after it is transferred than it is in unmated bacteria. This sensitivity seems to depend on a sensitive state of the injected material, rather than on a different physiological condition of the entire zygote. Irradiation of recipientuvr+bacteria much more strongly inhibited expression of injected genes than if the F−wasuvrs. Studies on mating systems are not very useful for learning about the function of unmated bacteria.
Ultraviolet-Induced Changes in the Infectivity of
Agrobacterium tumefaciens
Authors: Heberlein Gary T. , Lippincott James A.
Published: January 2020

The infectivity of
Agrobacterium tumefaciens
strain B6 irradiated with short-wavelength ultraviolet light was followed as a function of dose. Previously reported enhancements of B6 infectivity by ultraviolet irradiation, in samples inoculated after 1.75 hr of dark incubation at 27 C, or immediately following irradiation, were found to occur most frequently after losses in cell viability of 60% and of 90% or more, respectively. Changes in colony-forming ability and tumor-initiating ability with increasing dose showed no obvious correlation until the maximal infectivity promotion of samples inoculated immediately after irradiation was reached. Thereafter, both bacterial responses typically decreased in parallel. With low dose rates, infectivity promotions were obtained with less than 10% loss in cell viability. Data for tumor appearance and tumor growth resulting from inoculations with irradiated cultures showed no significant differences from controls, nor did the age of the bacterial culture or age of the host plant influence the response. The infectivity promotion appears to result from an increase in the proportion of viable cells that will subsequently initiate tumors. The characteristics of this ultraviolet infectivity promotion are shown to be most similar to those found in prophage and bacteriocin induction.
Phosphate Uptake in an Obligately Marine Fungus II. Role of Culture Conditions, Energy Sources, and Inhibitors
Authors: Siegenthaler Paul A. , Belsky Melvin M. , Goldstein Solomon , Menna Maria
Published: January 2020

Phosphate uptake in the obligately marine fungus,Thraustochytrium roseum, is maximal atpH 7.5 to 7.8, is dependent on temperature, and varies with phosphate concentration. Pyruvate and succinate stimulate phosphate uptake, although they do not increase respiration. The uncoupling agents, 2,4-dinitrophenol and dicoumerol, inhibit phosphate uptake but stimulate oxygen consumption only in the presence of NaCl. Oligomycin inhibits both processes. Among the inhibitors of protein synthesis, chloramphenicol reduces phosphate uptake without affecting respiration. Puromycin is unique in that it greatly enhances phosphate uptake and abolished the lag period associated with this phenomenon. It does not affect respiration.
Uptake and Utilization of Amino Acids by Resting Cells of
Nitrosomonas europaea
Authors: Clark Connie , Schmidt E. L.
Published: January 2020

Incorporation of selected amino acids by resting cells was studied with regard to effects of concentration, rate and extent of incorporation, cellular distribution, effect of ammonium ion on uptake, and competitive effects.
l
-Aspartic acid,
l
-alanine,
l
-serine, and glycine presented at trace levels were incorporated at rates ranging from 0.11 to 8.2 μμmoles per mg (dry weight) per minute, and maximal incorporation was 11 to 333 μμmoles per mg (dry weight). When glycine and aspartic acid were supplied at substrate level, the rate of incorporation increased 14- and 109-fold, respectively. The presence of ammonium ion further increased both the rate and extent of uptake of glycine and aspartic acid. The distribution of cellular radioactivity arising from
14
C amino acids indicated that cell pool radioactivity was concentrated from 1.2- to 24.5-fold over the external medium. Aspartic acid pool radioactivity accounted for 50% or more of the total cellular radioactivity, whereas radioactivity in glycine and serine pools dropped from initially high levels to 20 to 25% during incubation. The decrease in pool radioactivity with both glycine and serine was accompanied by an increase in other fractions, especially in the cell residue. The growth-inhibiting amino acid
l
-valine, supplied at substrate level, contributed more carbon per milligram (dry weight) than any other amino acid studied.
l
-Leucine, in the presence of
l
-valine, was observed to decrease valine incorporation.
Autolysis and Secondary Growth of
Mycobacterium tuberculosis
in Submerged Culture
Authors: Wayne Lawrence G. , Diaz Gilbert A.
Published: January 2020

Mycobacterium tuberculosis
has been found to exhibit autolysis and spontaneous secondary growth in modified Sauton medium. The phenomenon is a function of high glycerol concentration of the medium and limitation of air in test tubes. It is not a function of depletion of nutrients and is probably not a manifestation of lysogeny or spheroplast formation. The cycle of growth, autolysis, and secondary growth is related to development of lethal conditions during a period of severe oxygen limitation followed by a metabolic change associated with slower depletion of glycerol.
Selection of Characters for an Adansonian Analysis of Mycobacterial Taxonomy
Authors: Wayne Lawrence G.
Published: January 2020

Tests which are most frequently employed to provide characters for numerical analysis of bacterial taxonomy provide little differentiation among the slow-growing members of the genus
Mycobacterium
. A special scheme was proposed to deal with this problem. Characters were based, to some extent, on quantitative reactions to tests, and were defined, for each test, in terms of natural clustering behavior of a large collection of assorted strains. Inter- and intrataxon analyses were based on comparisons of reaction patterns with tentative hypothetical median strain patterns. This permitted the analysis of larger numbers of cultures than can be practically studied in a conventional
n
×
n
table.
Deoxyribonucleic Acid Synthesis During Exponential Growth and Microcyst Formation in
Myxococcus xanthus
Authors: Rosenberg Eugene , Katarski Mary , Gottlieb Peter
Published: January 2020

Myxococcus xanthus
in exponential phase with a generation time of 270 min contained a period of 50 min during which deoxyribonucleic acid (DNA) synthesis did not take place. After induction of microcysts by the glycerol technique, the DNA content increased 19%. Autoradiographic experiments demonstrated that the DNA made after glycerol induction was not evenly distributed among the microcysts. The distribution of grains per microcyst fits the following model of chromosome replication: in exponential phase, each daughter cell receives two chromosomes which are replicated sequentially during 80% of the divison cycle; after microcyst induction, no chromosomes are initiated. Mathematical formulas were derived which predict the kinetics and discrete probability distribution for several chromosome models.
Genetic Analysis of Glutamate Transport and Glutamate Decarboxylase in
Escherichia coli
Authors: Marcus Menashe , Halpern Yeheskel S.
Published: January 2020

The location of the
Escherichia coli
K-12 genes determining or regulating glutamate transport, and the location of the gene determining glutamate decarboxylase synthesis, were established by conjugation. The ability to grow on glutamate as the sole source of carbon and energy was used to select for glutamate transport recombinants. Two genes determining the ability to grow on glutamate as the sole source of carbon and energy were mapped. One (
gltC
) is located near
mtl
(mannitol), and the other (
gltH
) appears to be located between the
gal
(galactose) and
trp
(tryptophan) loci. The glutamate decarboxylase gene (
gad
) is strongly linked to
gltC
. The
gltC
+
recombinants grow on glutamate much faster and accumulate this amino acid to a greater extent than do the
gltH
+
recombinants. The
gltH
+
gene functioned only in one female strain (P678), whereas the
gltC
gene functioned in all the female strains tested (P678, C600, W1).