bluuebunny/crossref_metadata_2025 huggingface dataset:
Cellulolytic Enzymes During Morphogenesis in
Dictyostelium discoideum
Authors: Rosness Per A.
Published: January 2020

Extracts from
Dictyostelium discoideum
at the sorocarp stage of development catalyzed the degradation of acid-swollen cellulose to
d
-glucose at an optimal
p
H of about 4.5; cellobiose and cellotriose were the major products from this degradation at
p
H 7.0. The optimal temperature at
p
H 7.0, when swollen cellulose was used as substrate, was about 45 to 48 C, and was somewhat lower at
p
H 4.2 to 4.5, i.e., about 40 C. To account for this degradation pattern, two types of enzymes have been characterized, cellulase(s) and β-glucosidase. With carboxymethyl cellulose as substrate, cellulase activity was not found in extracts prior to the sorocarp stage of development, but increased rapidly during aging of the sorocarp. Evidence is presented that at earlier stages of development the cellulase(s) is present in an inactive form. An inhibitor found in these extracts is heat-labile and probably of protein nature. The β-glucosidase is present at all stages of development and the specific activity changes about fourfold, the highest activity occurring during the culmination and sorocarp stages of development.
Oxidation of
d
(−) Lactate by the Electron Transport Fraction of
Azotobacter vinelandii
Authors: Jurtshuk Peter , Harper Lahoma
Published: January 2020

d
(−) Lactate oxidation in
Azobacter vinelandii
strain O is readily carried out by the membrane bound enzyme that concentrates in the electron transport fraction (R
3
). This oxidation in the R
3
fraction is not dependent on externally added nicotinamide adenine dinucleotide, flavine adenine dinucleotide, or flavine mononucleotide. Phenazine methosulfate, O
2
, and menadione all served as good electron carriers, and the oxidation of lactate was limited to the
d
(−) stereoisomer. Of all the α-hydroxyacids examined, only
d
(−) lactate and
d
(−) α-hydroxybutyrate were oxidized by the R
3
fraction. Paper chromatographic studies revealed that the 2,4-dinitrophenylhydrazine derivative formed from
d
(−) lactate oxidation was pyruvate. Pyruvate, in turn, could be further decarboxylated nonoxidatively by the R
3
fraction. Spectral studies revealed that both the R
3
flavoprotein and cytochrome (
a
2
,
a
1
,
b
1
,
c
4
, and
c
5
) components were reduced by
d
(−) lactate. The
d
(−) lactic oxidase activity was sensitive to electron transport inhibitors, i.e., chlorpromazine, antimycin A, 2-
n
-heptyl-4-hydroxyquinoline-
N
-oxide, rotenone, dicumarol, and cyanide, and to a small extent to 4,4,4-trifluoro-1-(2-thienyl)-1,3-butane-dione (TFTB) and Amytal. The
d
(−) lactic phenazine methosulfate and menadione reductases were sensitive only to dicumarol and TFTB. Chlorpromazine was found to be a highly specific inhibitor of
d
(−) lactic oxidase activity, 50% inhibition occurring at 6.6 × 10
−6
m
.
MycoplasmaTaxonomy Studied by Electrophoresis of Cell Proteins
Authors: Razin Shmuel
Published: January 2020

The electrophoretic patterns of cell proteins in polyacrylamide gels were used for the study of several taxonomic problems in theMycoplasmatales. The patterns of fiveMycoplasma hominisstrains showed marked differences that corresponded with their known serological and nucleic acid heterogeneity. The patterns of threeM. mycoidesvar.mycoidesstrains isolated in different countries were essentially identical. The electrophoretic patterns of several caprine strains resembled those ofM. mycoidesvar.mycoides, supporting their classification asM. mycoidesvar.capri. Strain B3, a swine isolate, accordingly was tentatively identified asM. mycoidesvar.capri. The bovine mastitis strainM. agalactiaevar.bovispossessed a pattern basically similar to that of the goat mastitis strainM. agalactiae, supporting the inclusion of both strains in one species. ThreeM. pulmonisstrains isolated from rats or tissue cultures showed nearly identical patterns. The pattern of the toxigenicM. neurolyticum(Sabin A) strain resembled but was not identical with that of the nontoxigenic PG28 strain. The avianMycoplasmaspecies,M. gallisepticum, M. meleagridis, M. synoviae, M. gallinarum, andM. inersshowed easily distinguishable and specific patterns, supporting their present classification in different species. Several improvements in the electrophoretic technique are described, and its advantages and limitations as a taxonomic tool are discussed.
Adsorption ofMycoplasma pneumoniaeto Neuraminic Acid Receptors of Various Cells and Possible Role in Virulence
Authors: Sobeslavsky O. , Prescott B. , Chanock R. M.
Published: January 2020

Monkey, rat, and chicken tracheal epithelial cells, as well as monkey, rat, guinea pig, and chicken erythrocytes, adsorbed firmly to colonies ofMycoplasma pneumoniaeandM. gallisepticum. Colonies ofM. pulmonisalso adsorbed erythrocytes but with less avidity thanM. pneumoniaeorM. gallisepticum; unlike the latter organisms,M. pulmonisdid not adsorb tracheal epithelial cells. Colonies ofM. oraletype 1 andM. oraletype 3 adsorbed only chicken red cells. Other mycoplasma species tested, including four of human origin and one of animal origin, did not adsorb red cells or epithelial cells.M. pneumoniaeandM. gallisepticumappeared to attach to erythrocytes or tracheal epithelial cells by neuraminic acid receptors on these cells, whereasM. oraletypes 1 and 3 andM. pulmonisseemed to utilize another type or other types of receptors. Pretreatment of red cells or tracheal epithelial cells with receptor-destroying enzyme, neuraminidase, or influenza B virus removed the adsorption receptors forM. pneumoniae. Similarly, pretreatment ofM. pneumoniaecolonies with neuraminic acid-containing materials prevented adsorption of erythrocytes or respiratory tract cells. The adsorption sites onM. pneumoniaewere specifically blocked by homologous but not heterologous antisera. This property made it possible to study the nature of the mycoplasma adsorption sites by testing the capacity of different fractions of the organism to block the action of adsorption-inhibiting antibodies. Such studies suggested that the mycoplasma binding sites were probably lipid or lipoprotein in nature. The glycerophospholipid hapten was implicated as one such site, since this serologically active hapten blocked the action of hemadsorption-inhibiting antibodies inM. pneumoniaerabbit antiserum. The affinity ofM. pneumoniaefor respiratory tract epithelium, unique among the mycoplasmas that infect man, may play a role in virulence, since this type of attachment provides an unusual opportunity for peroxide, secreted by the organism, to attack the tissue cell membrane without being rapidly destroyed by catalase or peroxidase present in extracellular body fluids.
Secretion of Alkaline Phosphatase Subunits by Spheroplasts of
Escherichia coli
Authors: Schlesinger Milton J.
Published: January 2020

Under conditions that permitted continued protein synthesis, spheroplasts of
Escherichia coli
were unable to form
active
alkaline phosphatase, although they synthesized protein that was antigenically related to alkaline phosphatase subunits. This cross-reacting protein was primarily detected in the medium of the spheroplast culture, and it had properties that closely resembled those of the alkaline phosphatase subunit. These results suggest that formation of the active alkaline phosphatase dimer by intact
E. coli
cells proceeds by a pathway in which inactive subunits released from polyribosomes diffuse through the bacterial cell membrane to a periplasmic space where subsequent dimerization to active enzyme occurs. This pathway provides a possible mechanism for the specific localization of this enzyme to the
E. coli
periplasmic space.
Inhibition by Methylphenidate of Transport Across the Yeast Cell Membrane
Authors: Spoerl Edward , Doyle R. J.
Published: January 2020

The influence of methylphenidate on glycolysis in yeast cells was studied to describe more fully the nature of the reactions in which this drug participates. CO
2
production and O
2
uptake of yeast cells was inhibited 75% by a 10 m
m
concentration of the compound. This effect, with glucose as a substrate, occurred at
p
H 7.0, but not at
p
H 4.5. Kinetic data indicated that the reaction was noncompetitive and complex; the methylphenidate effect on CO
2
production could not readily be reversed. Glycolysis by cell-free extracts was not inhibited at the 10-m
m
concentration, but was affected at 100 m
m
. Utilization of O
2
with maltose and ethyl alcohol as substrates also was reduced. Entry into the cells of a number of different carbohydrates and of glycine was inhibited to different degrees. The loss from suspended cells of materials absorbing at 280 nm was reduced, and the efflux of sorbose, arabinose, and lactose was decreased. Thus, transport into and out of the cells was inhibited and leakage, or permeability, was reduced. It is hypothesized that methylphenidate reacts with a cell membrane constituent, or constituents, and inhibits glycolysis by blocking sugar passage.
Studies on Microbial Ribonucleic Acid VI. Appearance of Methyl-deficient Transfer Ribonucleic Acid During Logarithmic Growth of
Saccharomyces cerevisiae
Authors: Kjellin-Stråby Kerstin , Phillips John H.
Published: January 2020

Transfer ribonucleic acid (tRNA) that is deficient in methyl groups may be detected in logarithmically growing
Saccharomyces cerevisiae
. The amount of methyl-deficient tRNA is not constant throughout the logarithmic phase, but is maximal about one generation before the onset of the late growth phase. During this latter phase, the tRNA is fully methylated. The methyl-deficient tRNA is present during a period of high metabolic activity of the cell, characterized by increased RNA and protein content.
Inhibition of Fibrinogen Reaction by Polysaccharide of Encapsulated
Staphylococcus aureus
Authors: Blackstock Rebecca , Hyde Richard M. , Kelly Florene C.
Published: January 2020

Encapsulated and nonencapsulated strains of
Staphylococcus aureus
which lack coagulase or clumping factor (bound coagulase), or both, were examined for the antigen associated with the fibrinogen-cell clumping reaction. Extracts of the cells were tested for the ability to react with fibrinogen or to inhibit fibrinogen precipitation. Antisera prepared against encapsulated (coagulase-positive, clumping factor-negative) variants, as well as against nonencapsulated wild-type (coagulase-positive, clumping factor-positive)
S. aureus
strains, contained high titers of clumping-inhibiting antibody. When coagulase-negative, clumping factor-negative mutants were the immunizing agents, antisera contained no demonstrable clumping-inhibiting antibody. Phenol extracts of all coagulase-positive strains tested precipitated fibrinogen, regardless of the ability of cells to clump in the presence of fibrinogen. Polysaccharide extracts of encapsulated, clumping factor-negative strains inhibited this fibrinogen-precipitating activity, whereas similar extracts of nonencapsulated staphylococci did not inhibit the fibrinogen reaction. From these results, it appeared that the coagulase-positive, encapsulated staphylococci which do not clump in fibrinogen solution possess clumping factor, but that their capsular polysaccharide inhibits clumping activity. These findings suggested a closer association of clumping factor and coagulase than is now recognized.
Fine Structure of
Spirochaeta stenostrepta
, a Free-living, Anaerobic Spirochete
Authors: Holt S. C. , Canale-Parola E.
Published: January 2020

The fine structure of
Spirochaeta stenostrepta
strain Z1, a free-living anaerobic spirochete, was studied by electron microscopy. The organism possessed a coiled protoplasmic cylinder, an axial filament inserted subterminally, and a loosely fitting sheath which enclosed both the protoplasmic cylinder and the axial filament. The axial filament consisted of two fibrils partially overlapping in a 1-2-1 arrangement. The axial fibrils appeared to possess a sheath surrounding an inner core. Both inner core and sheath were apparently enclosed in a cross-striated tubular structure, which was itself surrounded by an outer sheath. The axial filament exhibited a basal hook. A disc- or mushroom-shaped structure, possibly consisting in part of cytoplasmic membrane, was observed at the insertion end of isolated filaments. The protoplasmic cylinder had a distinctive surface structure consisting of an array of tightly packed, longitudinally arranged helices measuring 2.0 to 2.5 nm in diameter. This layer of helices lay below the outer cell sheath and the axial filament. Ballistic disintegration loosened the helical array, causing individual helices or segments of helices to become separated from the cell. The function of this layer of helices is still obscure.
Ultrastructure of the Cell Wall and Cell Division of Unicellular Blue-green Algae
Authors: Allen Mary Mennes
Published: January 2020

The fine structure of the cell wall and the process of cell division were examined in thin sections of two unicellular blue-green algae grown under defined conditions. Unilateral invagination of the photosynthetic lamellae is the first sign of cell division in the rod-shaped organism,
Anacystis nidulans
. Symmetrical invagination of the cytoplasmic membrane and inner wall layers follows. One wall layer, which appears to be the mucopolymer layer, is then differentially synthesized to form the septum; the outer wall layers are not involved in septum formation. Centripetal splitting of the inner layer separates the two daughter cells. A second division, in a plane parallel to the first, usually occurs before the first daughter cells are separated. In the coccoid organism,
Gleocapsa alpicola
, the features of cell division are broadly similar; however, unilateral invagination of the lamellae is not observed and the second division takes place in a plane perpendicular to the plane of the previous division.
Proline as an Intermediate in the Reductive Deamination of Ornithine to δ-Aminovaleric Acid
Authors: Costilow Ralph N. , Laycock Loretta
Published: January 2020

Fresh extracts of cells of
Clostridium botulinum
reduced a limited amount of ornithine to δ-aminovaleric acid, but at high substrate concentrations a considerable amount of an amino compound accumulated which was neutral at
p
H 4.2. Aging of the extracts at −10 C or freezing and thawing resulted in the loss of the ability to produce δ-aminovaleric acid, but the ability to produce the neutral compound was retained. This compound was separated by column chromatography, and was found to be identical to
dl
-proline with respect to (i)

R
F

upon paper chromatography, (ii) migration rates upon paper ionophoresis, (iii) spectrum of the product of the ninhydrin reaction, (iv) oxidation with
d
-amino acid oxidase, and (v) rate of reduction to δ-aminovaleric acid by cell extracts. The intermediate role of proline in the reduction of ornithine to δ-aminovaleric acid was indicated by (i) rate studies with and without an added electron donor and with and without inhibitors of proline reductase, (ii) the initial accumulation of radioactive proline to the exclusion of radioactive δ-aminovaleric acid from
14
C-
l
-ornithine in the presence of low levels of carrier proline, and (iii) the initial accumulation of proline at low levels prior to a significant accumulation of δ-aminovaleric acid in reaction mixtures in which the latter compound was the primary product after a longer incubation time. The conversion of ornithine to proline was the rate-limiting step in the presence of a good electron donor (alanine). The mechanism of the conversion of ornithine to proline has not been established. Preliminary data indicated that it may involve an oxidation to glutamic-γ-semialdehyde and its equilibrium product, Δ
1
-pyrroline-5-carboxylic acid.
Altered Diaphorase Activity in Optochin-resistant Pneumococci
Authors: Kreger Arnold S. , Olsen Ronald H. , Talmadge Marvin B.
Published: January 2020

Methylene blue (MB) reductase activities of washed cell suspensions and of cell-free extracts prepared from optochin-resistant mutant pneumococci were two times greater than and four to eight times more resistant to optochin inhibition than those of similar preparations from the optochin-sensitive parent strains. With whole cells, optochin hydrochloride was approximately four times more potent than quinine hydrochloride in inhibiting MB reductase activity. However, with cell-free extracts, both drugs had similar inhibitory activities. Glucose uptake was not affected by optochin hydrochloride, and both optochin-sensitive and optochin-resistant pneumococci had similar glucose uptake patterns. Diaphorase activities of cell-free extracts prepared from optochin-resistant pneumococci were two times greater than and four to eight times more resistant to optochin inhibition than those of cell-free extracts prepared from the optochin-sensitive parent strains. Flavin concentrations of cell-free extracts prepared from optochin-sensitive and optochin-resistant strains were similar.
Protein Synthesis During Fungal Spore Germination II. Aminoacyl-soluble Ribonucleic Acid Synthetase Activities During Germination of
Botryodiplodia theobromae
Spores
Authors: Etten James L. Van , Brambl Robert M.
Published: January 2020

The specific activities of 13 aminoacyl-soluble ribonucleic acid (sRNA) synthetases were measured at various time intervals during the germination of
Botryodiplodia theobromae
conidiospores. The enzyme activities were low or absent in ungerminated spores, and they increased rapidly as germination proceeded. When extracts of the ungerminated spores were prepared with mortar and pestle, very little or no enzyme activity was detected. When the extracts were prepared with a mechanical homogenizer, however, they exhibited some enzyme activity, although less than did the extracts from germinated spores. Enzyme activities from germinated spores were approximately the same, regardless of the method of preparation. The enzyme fraction from ungerminated spores prepared with a mechanical homogenizer could also stimulate incorporation of phenylalanine into polyphenylalanine in the presence of ribosomes, polyuridylic acid, and sRNA, although the activity was approximately only 15 to 20% that of a similar enzyme fraction from germinated spores. It is concluded that ungerminated spores of
B. theobromae
contain active aminoacyl-sRNA synthetases and transfer enzymes, although the activities are low when compared to germinated spores.
Role of Pyruvate and
S
-Adenosylmethionine in Activating the Pyruvate Formate-Lyase of
Escherichia coli
Authors: Chase Theodore , Rabinowitz Jesse C.
Published: January 2020

The pyruvate formate-lyase activity of extracts of
Escherichia coli
is stimulated and the dilution effect is abolished by the addition of pyruvate to the extract. The activity can be purified fourfold from pyruvate-supplemented extracts by isoelectric precipitation under anaerobic conditions. The activity of extracts not supplemented with pyruvate has been separated into two fractions by treatment with protamine sulfate—fraction PS, the soluble portion, and fraction N, an extract of the precipitate formed upon the addition of protamine sulfate. After treatment of these fractions with charcoal, pyruvate formate-lyase activity is stimulated by the addition of
S
-adenosylmethionine. When sodium pyruvate is added to the crude extract before the fractionation, fraction PS has full enzymatic activity and is not stimulated by fraction N or by
S
-adenosylmethionine. Incubation of the inactive fractions with pyruvate and
S
-adenosylmethionine in the absence of other substrates similarly results in a highly active preparation, not subject to the “dilution effect” obtained when the fractions are added separately to the assay. These observations suggest that the component in the protamine supernatant fraction is activated by the other fraction and that
S
-adenosylmethionine and pyruvate are required for the activation reaction. The activating factor present in the protamine precipitate fraction may be further purified by heating for 10 min at 100 C under H
2
atmosphere. The yield of this factor from crude extract is not affected by activation of the pyruvate formate-lyase of the extract, indicating that the factor acts catalytically. The requirement for pyruvate is only partially satisfied by α-ketobutyrate and not at all by other α-keto acids, acetyl phosphate, or adenosine triphosphate. The rate of activation is maximal at 0.01
m
sodium pyruvate and 3 × 10
−4
m
S
-adenosylmethionine; it is linearly dependent on the amount of activating factor added. The rate of activation is the same when the activation reaction is initiated by addition of any of the four required components, indicating that no slow step of activation can be carried out by any three of the components. A similar pyruvate formate-lyase system was found in extracts of the methionine/B
12
autotroph 113-3, grown with methionine supplement, indicating that vitamin B
12
derivatives do not participate in the system.
Site in Cell-free Protein Synthesis Sensitive to Diphtheria Toxin
Authors: Johnson William , Kuchler Robert J. , Solotorovsky Morris
Published: January 2020

The effects of diphtheria toxin on cell-free protein synthesis in a bacterial system, and preparations obtained from animals that were sensitive and resistant to toxin were examined. In the presence of nicotinamide adenine dinucleotide (NAD), toxin inhibited the incorporation of amino acids by endogenous and synthetic polynucleotides in both rat liver and guinea pig liver cell-free systems that were exposed to 6 Lf units per ml of toxin. A cell-free system derived from
Streptococcus faecalis
was resistant to high concentrations of toxin. Dialyzed toxin-antitoxin floccules that are formed in the presence of NAD and the 105,000 ×
g
supernatant fluid from rat liver contain NAD. Such floccules are also active in protein synthesis in the absence of added transferase I or II. An operational model presents the view that the intoxication complex is formed at the ribosomal level and occurs in two steps. First, the toxin molecule binds to transferase II and alters its stereospecific relationship to transferase I, but it does not result in an inactive complex. Second, the stereospecific alteration in transferase I, but it does not result in an inactive complex. Second, the stereospecific alteration in transferase II caused by the binding of diphtheria toxin allows NAD to bridge between transferase I and II, which then results in an inactivated complex. The sensitivity of the cell-free system derived from the normally resistant rat implies that in some cells the cell membrane serves as a permeability barrier to the toxin molecule. The resistance of bacterial cell-free protein synthesizing systems to diphtheria toxin may reflect basic differences between transferase enzymes from bacterial and mammalian sources.
Effect of Chlorphenesin on Localized Hemolysis in Gel Assay
Authors: Fukui G. M. , Berger F. M. , Chandlee G. C. , Goldenbaum E. G.
Published: January 2020

Chlorphenesin, a simple glycerol ether, when added to Jerne plates greatly reduced the number of hemolytic plaques. This effect appeared to be related to dose, and was clearly demonstrable with antibody-forming spleen cells from mice that had been immunized either with sheep red blood cells or with penicillin G conjugated with Keyhole limpet hemocyanin. Chlorphenesin did not affect the antigen, destroy complement, or interfere with the interaction of complement and the antigen-antibody complexes. Incubation of spleen cell suspensions with chlorphenesin prior to plating was more effective in reducing the number of plaques than was addition of the substance to the plates. It may act by reducing the ability of antibodies to react with antigens or by affecting the release of antibodies from the spleen cells.
Uridine Diphosphate
d
-Glucose Dehydrogenase of
Aerobacter aerogenes
Authors: Bdolah Avener , Feingold David S.
Published: January 2020

Uridine diphosphate
d
-glucose dehydrogenase (EC 1.1.1.22) from
Aerobacter aerogenes
has been partially purified and its properties have been investigated. The molecular weight of the enzyme is between 70,000 and 100,000. Uridine diphosphate
d
-glucose is a substrate; the diphosphoglucose derivatives of adenosine, cytidine, guanosine, and thymidine are not substrates. Nicotinamide adenine dinucleotide (NAD), but not nicotinamide adenine dinucleotide phosphate, is active as hydrogen acceptor. The
p
H optimum is between 9.4 and 9.7; the
K
m
is 0.6 m
m
for uridine diphosphate
d
-glucose and 0.06 m
m
for NAD. Inhibition of the enzyme by uridine diphosphate
d
-xylose is noncooperative and of mixed type; the
K
i
is 0.08 m
m
. Thus, uridine diphosphate
d
-glucose dehydrogenase from
A. aerogenes
differs from the enzyme from mammalian liver, higher plants, and
Cryptococcus laurentii
, in which uridine diphosphate
d
-xylose functions as a cooperative, allosteric feedback inhibitor.
Lipid Composition of the Electron Transport Membrane of
Haemophilus parainfluenzae
Authors: White David C.
Published: January 2020

The principal lipids associated with the electron transport membrane of
Haemophilus parainfluenzae
are phosphatidylethanolamine (78%), phosphatidylmonomethylethanolamine (0.4%), phosphatidylglycerol (18%), phosphatidylcholine (0.4%), phosphatidylserine (0.4%), phosphatidic acid (0.2%), and cardiolipin (3.0%). Phospholipids account for 98.4% of the extractible fatty acids. There are no glycolipids, plasmalogens, alkyl ethers, or lipo amino acid esters in the membrane lipids. Glycerol phosphate esters derived from the phospholipids by mild alkaline methanolysis were identified by their staining reactions, mobility on paper and ion-exchange column chromatography, and by the molar glycerol to phosphate ratios. Eleven diacyl phospholipids can be separated by two-dimensional thin-layer chromatography. Each lipid served as a substrate for phospholipase D, and had a fatty acid to phosphate ratio of 2:1. Each separated diacyl phospholipid was deacylated and the glycerol phosphate ester was identified by paper chromatography in four solvent systems. Of the 11 separated phospholipids, 3 were phosphatidylethanolamines, 2 were phosphatidylserines, and 2 were phosphatidylglycerols. Phosphatidylcholine, cardiolipin, and phosphatidic acid were found at a single location. Phosphatidylmonomethylethanolamine was found with the major phosphatidylethanolamine. Three distinct classes of phospholipids are separable according to their relative fatty acid compositions. (i) The trace lipids consist of two phosphatidylethanolamines, two phosphatidylserines, phosphatidylcholine, phosphatidic acid, and a phosphatidylglycerol. Each lipid represents less than 0.3% of the total lipid phosphate. These lipids are characterized by high proportions of the short (C
10
to C
14
) and long (C
19
to C
22
) fatty acids with practically no palmitoleic acid. (ii) The major phospholipids (93% of the lipid phosphate) are phosphatidylethanolamine, phosphatidylmonomethylethanolamine, and phosphatidylglycerol. These lipids contain a low proportion of the short (<C
14
) and long (>C
19
) fatty acids. Palmitic and palmitoleic acids represent over 80% of the total fatty acids. (iii) The fatty acid composition of the cardiolipin is intermediate between the other two classes. Both palmitoleic and the longer fatty acids represent a significant proportion of the total fatty acid.
Inhibition of Hepatic Enzyme Induction as a Sensitive Assay for Endotoxin
Authors: Berry L. Joe , Smythe Dorothy S. , Colwell Louise S.
Published: January 2020

Bacterial endotoxins in mice reduced the induction by cortisone of two hepatic enzymes, tryptophan oxygenase, and phosphoenolpyruvate carboxykinase, they prevented the glyconeogenesis in liver induced by the same hormone, and they induced in intact animals the liver enzyme tyrosine-α-ketoglutarate transaminase, all in proportion to their
ld
50
. When cortisone was given in the least amount (100 μg), it resulted in near maximal induction of tryptophan oxygenase; a smaller amount of endotoxin reduced significantly the level of enzyme than that required when 5 mg of hormone was injected. The smallest amount of endotoxin that prevented tryptophan oxygenase induction was given intravenously to adrenalectomized mice in which 25 μg of cortisone was administered. The amount (0.01 μg) is 1/40,000th of the
ld
50
. The other metabolic processes subject to alteration by endotoxin required at least 100 to 400 times as much. This property of endotoxin can serve as a sensitive bioassay, although the dose-response curve is steep.
Alkaline Phosphatase Subunits and Their Dimerization In Vivo
Authors: Torriani Annamarie
Published: January 2020

A pool of alkaline phosphatase subunits has been found in cells of
Escherichia coli
which are actively synthesizing the enzyme. The radioactive subunits from pulse-labeled cells were specifically recognized by their capacity to produce, upon incubation with Zn
++
and nonradioactive monomers, radioactive dimers with the characteristics of alkaline phosphatase. The pool of subunits was larger (10 times or more) than the amount expected to be bound to ribosomes and was bound to a rapidly sedimentable fraction from which 60% was released by ribonuclease. In a culture pulse-labeled for one-third (8 sec) of the enzyme synthetic time, the pool of radioactive monomers was 81% of the radioactive enzyme and was totally (98%) in the endoplasm. The size of the pool was increased by decreasing the dimerization rate without affecting protein synthesis. This was achieved by decreasing Zn
++
in the growth medium. It was found that the cells contained a full complement of monomers, although the level of active enzyme was low. A process subsequent to the release of the monomers from the ribosomes was found to be limiting the formation of the finished enzyme. This process affects the level of the pool of monomers independently from their synthesis.
Regulation of Deoxyribonucleic Acid Replication and Cell Division in
Escherichia coli
B/r
Authors: Clark D. Joseph
Published: January 2020

Synchronous cultures of
Escherichia coli
strain B/r were used to investigate the relationship between deoxyribonucleic acid (DNA) replication and cell division. We have determined that terminal steps in division can proceed in the absence of DNA synthesis. Inhibition of DNA replication with nalidixic acid prior to the start of a new round of replication does not stop cell division, which indicates that the start of the round is not essential in triggering cell division. Inhibition of DNA replication at any time prior to the termination of a round of replication completely blocks cell division, which suggests that there may be a link between the end of the replication cycle and the commitment of the cell to divide. Studies that use a temperature-sensitive mutant which is unable to synthesize DNA at the nonpermissive temperature are in complete agreement with those that use nalidixic acid to inhibit DNA synthesis. This adds support to the idea that the treatments employed limit their action to DNA synthesis. Investigation of minicell production indicates that the production of minicells is blocked when DNA synthesis is inhibited with nalidixic acid. Although nuclear segregation is not required for cell division, DNA synthesis is still required to trigger division. The evidence presented suggests strongly that (i) DNA synthesis is essential for cell division, (ii) the end of a round of replication triggers cell division, and (iii) there is considerable time lapse (one-half generation) between the completion of a round of DNA replication and physical separation of the cells.
Transformation of Type Polysaccharide Antigen Synthesis and Hemolysin Synthesis in Streptococci
Authors: Willers Jan M. , Deddish Peter A. , Slade Hutton D.
Published: January 2020

Transformation of the ability to synthesize type polysaccharide antigen and β-hemolysin has been obtained in group F streptococci. Colonies possessing cells transformed to antigen synthesis were detected on the agar surface with fluorescein-labeled anti-type serum. This selection method, in contrast to those with antibiotics, allowed both transformed and nontransformed cells to grow, resulting in sectored colonies. These colonies could be subcultured to further establish the synthesis of antigen. Group F, group A, and group-like z deoxyribonucleic acid (DNA) labeled with type II antigen and hemolysin, and streptomycin resistance transferred each marker to a group F strain lacking a type antigen. DNA from group F and z3 strains labeled with type III antigen, and streptomycin resistance transferred both markers to group F and z3 strains lacking type antigen. A second F strain without type antigen was not transformed with any of these markers. A group H strain was transformed to streptomycin resistance only by the same types of DNA. Transformation to type II antigen synthesis always resulted in the formation of β-hemolysin. All strains isolated from natural sources contained both markers. A mutant, obtained by nitrosoguanidine treatment of an FII
sr
strain, did not synthesize either the hemolysin or the antigen. This mutant still possessed the group antigen and streptomycin resistance. A close linkage of type II antigen and β-hemolysin is indicated. The fluorescent-antibody staining of cells containing both group and type antigens showed a more intense ultraviolet adsorption for type than group antigen. A surface location (microcapsular) for the type antigen appeared likely. These results are of interest for studies on antigen biosynthesis, genetics, and classification of the streptococci.
Characteristics of Penicillinase Release by Washed Cells of
Bacillus licheniformis
Authors: Sargent M. G. , Ghosh B. K. , Lampen J. O.
Published: January 2020

Saline-washed cells of
Bacillus licheniformis
strain 749/C (constitutive for penicillinase) were able to release exopenicillinase in the presence of concentrations of chloramphenicol that prevented protein synthesis completely. The release reaction was strongly
p
H-dependent, occurring at a faster rate at alkaline
p
H in anionic or cationic buffers than at neutral
p
H. A strongly
p
H-dependent release reaction was noted in growing cells also. The reaction in washed cells can be stopped completely by changing the
p
H to 6.0. Within 30 min at
p
H 9.0, about 55% of the cell-bound penicillinase was released; thereafter, release continued at a greatly reduced rate. Suspensions of washed cells retained their capacity to release penicillinase at
p
H 9.0 for 90 min. Penicillinase released at
p
H 9.0 from either cells or protoplasts was not readsorbed over a 60-min period after changing the
p
H to 6.0. The release reaction was strongly temperature-dependent. We examined the effect of a large number of metabolic inhibitors and other compounds on the
p
H-dependent release phenomenon. Quinacrine hydrochloride, chloroquine diphosphate, and chlorpromazine hydrochloride reduced secretion substantially at 10
−4
m
. Deoxycholate and Triton X-100 were active at 10
−3
m
, but tungstate, arsenate, and molybdate had small effects at 10
−1
m
. The rate of exopenicillinase release at
p
H 9.0 from fully stabilized protoplasts was one-half that of intact cells. Protoplasts lysed in hypotonic media or detergents showed even greater reduction in releasing activity. Penicillinase released from washed cells at
p
H 7.5 or 9.0 appeared to be derived from the periplasmic tubule and vesicle fraction that was released by protoplast formation.
Arylamidase of
Neisseria catarrhalis
Authors: Behal Francis J. , Cox Sidney T.
Published: January 2020

Neisseria catarrhalis
produces arylamidase intracellularly and is one of the gram-negative bacteria producing exceptionally large amounts of this enzyme.In general, gram-positive bacteria do not produce this enzyme. Arylamidase from
N. catarrhalis
was purified by salt fractionation, chromatography, and density gradient ultracentrifugation. Its sedimentation coefficient was 6.6;
l
-alanine-β-naphthylamide (βNA) was the most rapidly hydrolyzed amino acid-βNA. The enzyme had
p
K
e
values of 6.1 and 8.7 and
p
K
es
values of 7.1 and 7.9; only those amino acid-βNA compounds of the
l
configuration were susceptible to hydrolysis. Arylamidase catalyzed stepwise hydrolysis of dipeptide-βNA, beginning with the N-terminal residue. Substrates having amino acid residues with larger R groups, such as leucine, interacted much more effectively with enzyme. The significance of the predominate occurrence of arylamidase activity in gram-negative bacteria and the role of this enzyme in the physiology of these organisms remain unclear. It has been established, however, that arylamidase is distinct from leucine aminopeptidase.
Cytochemistry of Phosphatases in
Myxococcus xanthus
Authors: Voelz Herbert , Ortigoza Raoul O.
Published: January 2020

An Mg
2+
-dependent and a K
+
-stimulated adenosine triphosphatase were localized by cytochemistry at or near both surfaces of the cytoplasmic membrane of
Myxococcus xanthus
. An alkaline and an acid phosphatase resided at the external surface of the membrane or in the periplasm. All enzymes could be extracted from partially fixed cells with Mg
2+
-deficient buffers. Suboptimal external phosphate elicited dissociation of adenosine triphosphatase from the membrane but not that of the unspecific phosphatases. The dissociated enzymes migrated into the cytoplasm where they were associated mainly with cytoplasmic aggregates.
T6r
+
-induced Proteins and Nucleic Acids in
Escherichia coli
Infected in the Presence of Streptomycin
Authors: Freda Celia E. , Nass Margit M. K. , Cohen Seymour S.
Published: January 2020

Streptomycin does not strongly inhibit T-even phage multiplication in the streptomycin-susceptible polyauxotroph,
Escherichia coli
strain T
−
H
−
U
−
. The relatively slight inhibition, observed earlier, on production of late proteins has now been studied further. The phage-induced ribonucleic acid, synthesized in T6 phage infection in the presence of streptomycin, has been characterized by its base composition, size distribution, and behavior in hybridization tests. Comparison of these properties to those of control samples, taken during either early or late periods of infection, have not shown any significant differences. Phage-induced proteins, synthesized at different times during infection, were studied by disc-gel electrophoresis. Staining and autoradiography of the patterns of pulse-labeled proteins, formed in the absence and presence of the antibiotic showed only slight quantitative changes in the appearance of early proteins. More marked quantitative effects were detected later in infection. Nevertheless, changes in the mobilities of the different proteins were not observed in the streptomycin-treated cultures at any time after infection, suggesting the absence of gross misreading sufficiently great to alter the distinctive electrophoretic patterns of the extracts. Cells infected and incubated in the presence of the antibiotic were found to contain intact virus particles, as shown by electron microscopy. Such infected cells contained extensive deoxyribonucleic acid pools and did not develop the rounded nucleoids with enclosed dense bodies characteristic of the lethal action of the antibiotic. On the other hand, infected bacteria previously exposed to lethal concentrations of streptomycin were unable to synthesize the early enzymes, deoxycytidylate (dCMP) hydroxymethylase and dihydrofolate reductase, or to make phage deoxyribonucleic acid and phage. Such previously killed cells contained the rounded and clotted nucleoids and were unable to unravel this pathological structure after phage infection.
Cores, Microbial Organelles Possibly Specific to Group D Streptococci
Authors: McCandless Ruth G. , Cohen Morris , Kalmanson George M. , Guze Lucien B.
Published: January 2020

A long, thin, approximately cylindrical core spans the interior of cells of 24-hr cultures of all group D streptococci that were examined, five strains of
Streptococcus faecalis
, single strains of
S. faecalis
subsp.
zymogenes
and
S. durans
, and three strains of
Streptococcus
spp. In one strain of
S. faecalis
, serial section electron microscopy showed that most cells possess a core. The core is 0.10 to 0.16 μm thick and consists of a matrix and an axial array of ribosomelike particles. It resembles one of two types of cores present in a stable protoplast form of one of the
S. faecalis
strains. Cores were not present in single strains of
S. pyogenes
(β-hemolytic group A),
S. agalactiae
(group B),
S. dysgalactiae
(group C),
S. equisimilis
(group C), and
S. mitis
(viridans group) that were examined; nor were cores observed in single strains of
Staphylococcus aureus, Escherichia coli
, and
Bacillus megaterium
. Cores may be useful, therefore, in identification of group D streptococci. For preservation and rapid recognition of cores, a glutaraldehyde-osmium tetroxide sequence of fixation appears superior to the osmium tetroxide method often employed in processing bacteria for electron microscopy.
Protection by Vaccination Against
Pseudomonas
Infection After Thermal Injury
Authors: Markley Kehl , Smallman Elizabeth
Published: January 2020

Active immunization is effective in the prophylaxis of
Pseudomonas
septicemia in burned mice. Vaccines were prepared from bacterial cells and growth medium of Verder's 10 different O serological types of
Pseudomonas aeruginosa
strains, as well as from
Escherichia coli
and
Proteus mirabilis
. Mice given a tail burn could be significantly protected against a local
Pseudomonas
challenge by both specific and, to a lesser extent, by nonspecific
Pseudomonas
vaccines prepared either from bacterial cells or from the medium in which they were grown. The vaccine was effective when administered prior to or after thermal trauma. After a more extensive rump burn, the protective effect of a specific vaccine given after thermal injury was significant only when the challenge was postponed until 4 days postburn; the level of protection was less than in the mice with smaller burns.
Staphylococcal Hyaluronate Lyase: Purification and Characterization Studies
Authors: Abramson Carl , Friedman Herman
Published: January 2020

Staphylococcal hyaluronate lyase (hyaluronidase) derived from a pathogenic strain of staphylococcus was purified by means of salt fractionation with ammonium sulfate and gel filtration through Sephadex G-100. Most of the enzyme activity from concentrated culture supernatant fluids of staphylococci was obtained in a fraction precipitated by 90 to 100% saturation with ammonium sulfate. A small amount of enzyme was also precipitated by 80 to 90% saturation with the salt. The hyaluronidase-rich fractions did not contain other staphylococcal enzymes, such as coagulase, protease, lipase, and staphylokinase. These enzymes were present in the original concentrates. Molecular sieving chromatography of the partially purified enzyme by filtration through Sephadex G-100 resulted in a further increase in specific enzyme activity. However, more than one active peak was obtained after gel filtration, thus suggesting that there may be more than one molecular form of the enzyme. Immunodiffusion in agar gel of the chromatographically purified enzyme fraction, with immune serum from rabbits injected with concentrated staphylococcal culture supernatant fluids, indicated that there was one major antigen. A similar antigen, giving reactions of identity with the purified material, was present in the original culture supernatant fluid.
Lysosomes of
Toxoplasma gondii
and Their Possible Relation to the Host-Cell Penetration of Toxoplasma Parasites
Authors: Norrby Ragnar , Lindholm Leif , Lycke Erik
Published: January 2020

Lysosome-like structures of
Toxoplasma gondii
were observed by means of vital staining with acridine orange and by the Gomori technique. These structures were found scattered over the cytoplasm but were often located at one end of the parasite. In comparison with parasites of the inoculum used for infecting HeLa cell cultures, the toxoplasma which had penetrated the HeLa cells revealed a markedly lower percentage of parasites showing lysosomal staining. After the penetration, the number of parasites with demonstrable lysosomes increased successively and, at the time for release of newly formed parasites (at 24 hr), the majority of the parasites demonstrated lysosome-like bodies in the cytoplasm. The observations are discussed with special reference to the mechanism of host-cell penetration.
Oxidation of Alkanes to Internal Monoalkenes by a Nocardia
Authors: Abbott Bernard J. , Casida L. E.
Published: January 2020

A suspension of glucose-grown resting cells of
Nocardia salmonicolor
PSU-N-18 oxidized hexadecane to a mixture of internal monohexadecenes. The latter exhibited a
cis
configuration, and the mixture consisted of the following: 7-hexadecene, 80%; 8-hexadecene, 18%; and 6-hexadecene, 2%. Alkanes other than hexadecane also were unsaturated by the resting cells, and the composition of the monoalkenes resulting from octadecane dehydrogenation was 9-octadecene, 91%; 8-octadecene, 2 to 3%; 7-octadecene, 1 to 2%; and 6- and 5-octadecenes, trace amounts. Only minute quantities of unsaturated hydrocarbons accumulated during growth on hexadecane and during resting-cell incubation of hexadecane-grown cells with hexadecane. The dehydrogenation of hydrocarbons did not appear to be related to the formation of unsaturated fatty acids. It is postulated that double bond insertion may represent an early step in a new pathway of aliphatic hydrocarbon degradation.
Role of Relative Humidity in the Survival of Airborne
Mycoplasma pneumoniae
Authors: Wright D. N. , Bailey G. D. , Hatch M. T.
Published: January 2020

Aerosols of
Mycoplasma pneumoniae
were studied at several relative humidities at a controlled temperature of 27 C. Production of an experimentally reproducible aerosol required preatomization of the organism in its suspending fluid and was dependent on the type of fluid used in atomization as well as on the procedures used to produce an aerosol. The airborne particles studied were within the range of epidemiological significance, with most being 2 μm or less in diameter. Survival of the airborne mycoplasma in these particles was found to be best at very low and at very high humidities. The most lethal relative humidity levels were at 60 and 80%, at which levels fewer than 1% of the organisms survived over a 4-hr observation period. However, survival of the organism at most relative humidity levels was such that long-term infectivity could be expected from aerosols of
M. pneumoniae
. Because of the extreme sensitivity of
M. pneumoniae
at critical humidity levels, control of the airborne transmission of these organisms may be possible in selected spaces.
Deoxyribonucleic Acid Synthesis During Microcyst Germination in
Myxococcus xanthus
Authors: Zusman David , Rosenberg Eugene
Published: January 2020

Deoxyribonucleic acid (DNA) synthesis was measured during microcyst germination in
Myxococcus xanthus
by radioactive thymidine incorporation, autoradiography, and chemical analysis. Microcysts contained an average of 6.6 conserved units of DNA, corresponding to 3 to 4 chromosomes per cell. Correlation of the DNA content and chromosome number of microcysts indicated that the molecular weight of the nonreplicating
M. xanthus
chromosome is 4.9 × 10
9
daltons. DNA synthesis was initiated 3.5 to 4 hr after induction of germination. From 4 to 6 hr, the rate of synthesis was constant and the accumulation was linear. After a lag period (6 to 6.5 hr), the rate of DNA synthesis increased, reaching a second plateau at 9 hr. From 9 to 11 hr, the rate was again constant and the accumulation was linear. Cellular division during germination showed an unusual kind of synchrony. A model is presented that accounts for chromosomal replication and cell division during microcyst germination.