bluuebunny/crossref_metadata_2025_split huggingface dataset:
PROTEIN CONCENTRATION IN NORMAL MOUSE LYMPHOCYTES, THYMOCYTES, AND MOUSE AND HUMAN LEUKEMIC CELLS AS MEASURED BY INTERFERENCE MICROSCOPY
Authors: Ponder Eric , Ponder Ruth V. 
Published: May 2004

The apparent protein content of a single spherical lymphocyte or a similar cell, as well as its diameter, can be measured by a modified and stabilized AO-Baker interference microscope which is either fitted with an AO half-shade eyepiece or connected to a photomultiplier.
This paper gives results for the apparent protein content and the diameter of normal mouse lymphocytes and thymocytes; these do not differ significantly from each other. It also gives values for the apparent protein concentration and the diameter of the lymphocytes of mice of the same strain which have developed leukemia or lymphoma; these values are significantly different from those of normal mice. Related data are given for the apparent protein content and for the diameter of normal human lymphocytes and the white cells found in myeloblastic leukemia and in stem cell leukemia in man; here the values differ significantly from those of the normal human lymphocyte. The rule seems to be that the abnormal white cells become more watery and larger as the disease advances.
ELECTROKINETIC MEMBRANE PROCESSES IN RELATION TO PROPERTIES OF EXCITABLE TISSUES
Authors: Teorell Torsten 
Published: May 2004

An artificial system is studied consisting of salt solutions of different concentrations separated by a porous, "charged" membrane, through which a constant electric current is passed. Experiments on such systems demonstrate rhythmic variations of the transmembrane potential and the membrane resistance, which are concomitant with an oscillatory streaming of water solution across the membrane. The repetitive oscillations can be of a damped or undamped type dependent on the "stimulating" current density.
A qualitative discussion of the mechanism of the oscillations is given. It centers around the periodic resistance changes in the membrane, which result from a complicated interplay between the driving forces present. The importance of electro-osmotic effects is emphasized.
A few comparisons relating to possible electrophysiological implications are presented. In the metastable state of this membrane oscillator, "make" and "break" responses can be triggered by electric as well as by mechanical (pressure) "stimuli."
PATHWAYS OF TERMINAL RESPIRATION IN MARINE INVERTEBRATES
Authors: Ghiretti F. , Ghiretti-Magaldi Anna , Tosi Luisa 
Published: May 2004

The classic spectrophotometric method for identification and characterization of respiratory enzymes has been used for the study of the cytochrome system of Aplysia. Particles have been prepared from the buccal mass and the gizzard muscles. Difference spectra taken on isolated particle suspensions show the presence of a complete cytochrome system composed of five components: cytochrome a, b, c, c1, and a3. As indicated by the peaks of the sharp absorption bands of their reduced forms, they are very similar to the cytochromes of mammals and yeast. Cytochrome a3 has been identified as the terminal oxidase of Aplysia muscle by means of the spectrophotometric study of its carbon monoxide compound. Further evidence for the presence of a cytochrome system in Aplysia was obtained by assays of the catalytic activities of the isolated particles: succinic dehydrogenase, cytochrome oxidase, DPNH cytochrome c reductase. The cytochrome oxidase activity was strongly inhibited by carbon monoxide in the dark; the inhibition was totally relieved by light.
Cytochrome c has been extracted and purified from muscle tissue. Its spectrum is almost identical with that of the mammalian pigment both in the oxidized and reduced forms. From the hepatopancreas a new respiratory enzyme has been extracted which has many physical and chemical properties in common with cytochrome h from terrestrial snails.
THE ELECTROPHYSIOLOGY AND PHARMACOLOGY OF LOBSTER NEUROMUSCULAR SYNAPSES
Authors: Grundfest H. , Reuben J. P. , Rickles W. H. 
Published: May 2004

Effects of drugs on resting potential, membrane resistance, and excitatory and inhibitory postsynaptic potentials (e.p.s.p.'s and i.p.s.p.'s) of lobster muscle fibers were studied using intracellular microelectrodes Acetylcholine, d-tubocurarine, strychnine, and other drugs of respectively related actions on vertebrate synapses were without effects even in 1 per cent solutions (10- w/v). Gamma-aminobutyric acid (GABA) acted powerfully and nearly maximally at 10-7 to 10-6 w/v. Membrane resistance fell two- to tenfold, the resting potential usually increasing slightly. This combination of effects, which indicates activation of inhibitory synaptic membrane, was also produced by other short chain ω-amino acids and related compounds that inactivate depolarizing axodendritic synapses of cat. The conductance change, involving increased permeability to Cl-, by its clamping action on membrane potential shortened as well as decreased individual e.p.s.p.'s.
Picrotoxin in low concentration (ca. 10-7 w/v) and guanidine in higher (ca. 10-3 w/v) specifically inactivate inhibitory synapses. GABA and picrotoxin are competitive antagonists. The longer chain ω-amino acids which inactivate hyperpolarizing axodendritic synapses of cat are without effect on lobster neuromuscular synapse. However, one member of this group, carnitine (ß-OH-GABA betaine), activated the excitatory synapses, a decreased membrane resistance being associated with depolarzation. The pharmacological properties of lobster neuromuscular synapses and probably also of other crustacean inhibitory synapses appear to stand in a doubly inverted relation to axodendritic synapses of cat.
Muscle: A Three Phase System
Authors: Simon Shirley E. , Johnstone B. M. , Shankly K. H. , Shaw F. H. 
Published: May 2004

The partition of Li+, Br-, and I- across the membrane of the sartorius muscle of the toad Bufo marinus has been investigated both at the steady state and with kinetic methods. Li+ was found to have access to an amount of muscle water similar to that of Na+. Br- and I- could be regarded as being interchangeable with cellular Cl-. None of the foreign ions caused significant losses of cellular K+.
Li+ efflux from the cell was slower in muscles which were equilibrated for long periods in Li+ than in short equilibrated muscles. Na+ efflux from Li+-treated muscles was similar in rate to normal controls, but the amount of Na+ in the slow fraction was increased by Li+.
I- efflux was extremely rapid, and it was not possible to differentiate kinetically between intra- and extracellular material.
These results have been found to be consistent with the hypothesis of a three phase system for muscle.
Potassium Ions and the Inhibitory Process in the Crayfish Stretch Receptor
Authors: Edwards C. , Hagiwara S. 
Published: May 2004

The effect of the absence of potassium in the bathing solution on the synaptic inhibitory potentials of the crayfish stretch receptor has been studied.
The inhibitory potentials were increased in size, i.e. became more hyperpolarizing, in the absence of potassium. Since the resting potential of the cell is increased in the absence of potassium, the alteration of the inhibitory potentials implies that the potassium conductance of the membrane is increased. While other ions, e.g. Cl-, may also be involved, it seems that the membrane potential during inhibition is mainly dominated by K+.
Studies on the Role of N-Acetylaspartic Acid in Mammalian Brain
Authors: Jacobson K. Bruce 
Published: May 2004

N-Acetylaspartic acid (NAA) occurs at relatively high concentrations exclusively in the mammalian and avian brain and undergoes rapid rise in level soon after birth (Tallan, 1957).
The amount of NAA in brains of mentally abnormal human beings and of young human beings was measured. The route by which NAA is synthesized was shown to involve a direct acetylation of aspartic acid. The degradative activity of the brain toward NAA is slight. Some experiments indicate that NAA in the brain is a physiologically and metabolically active compound.
The Influence of pH and Ionic Strength on the Electrokinetic Stability of the Human Erythrocyte Membrane
Authors: Heard D. H. , Seaman G. V. F. 
Published: May 2004

The electrokinetic stability of washed normal human erythrocytes is discussed from the point of view of pH, ionic strength, and composition of the suspending medium. Many of the electrophoretic characteristics at low ionic strengths (sorbitol to maintain the tonicity), such as the isopotential points, are shown to arise principally from adsorption of hemolysate.
The concept of electrokinetically stable, metastable, and unstable states for the red cell at various ionic strengths is introduced in preference to the general term "cell injury." In the stable state which exists around pH 7.4 for ionic strengths &gt;0.007, no adsorption of hemolysate occurs, in the metastable state reversible adsorption of hemolysate occurs, and in the unstable state, in which ionic strengths and pH ranges are outside the metastable range, the membrane undergoes irreversible hemolysate adsorption or more general hydrolytic degradation.
It is deduced from the equivalent binding of CNS, I, Cl, and F, the pH mobility relationships, and the conformation of the ionic strength data in the stable state to a Langmuir adsorption isotherm, that the membrane of the human erythrocyte behaves as a macropolyanion whose properties are modified by gegen ion association and in some instances by hemolysate adsorption.
The experimental results are insufficient to establish conclusively the nature of the ionogenic groupings present in the membrane interphase.
Activity Patterns of Interneurons in the Caudal Ganglion of the Crayfish
Authors: Kennedy Donald , Preston James B. 
Published: May 2004

Responses of ascending interneurons from the caudal ganglion of crayfish have been recorded from single units isolated by dissection from the ventral nerve cord; in addition, post-synaptic activity within the ganglionic neuropile has been studied with intracellular micropipettes. The following classes of interneurons have been found: (1) Large fibers which responded to tactile stimuli with single spikes or phasic bursts. These units usually showed broad receptive fields; and spontaneous activity, when present, showed transitory depressions following responses to natural stimuli. (2) A group of fibers, including many small ones, which responded to proprioceptive stimuli with tonic discharges of varying adaptation rate. (3) Interneurons which showed responses both to tactile stimuli and to activation of the sixth ganglion photoreceptor; and (4) units with constant frequency discharges which were unmodifiable by any of the above afferent inputs.
Intracellular recording of post-synaptic activity has shown (1) that widely graded excitatory post-synaptic potentials occur; (2) that multiple firing from single synaptic potentials is usual; (3) that the post-synaptic responses to phasic natural stimuli and to electrical stimulation of ganglionic roots are similar.
The existence of widely graded post-synaptic potentials and of extensive receptive fields suggests a high degree of convergence from primary afferents to interneurons. The activation of such post-synaptic units involves integrative synaptic transfer, without 1:1 correspondence between pre- and post-fiber activity.
The Use of DFP32 as a Red Cell Tag with and without Simultaneous Tagging with Chromium51 in Certain Animals in the Presence or Absence of Random Destruction
Authors: Eadie G. S. , Smith Wirt W. , Brown Ivan W. 
Published: May 2004

DFP32, used to label erythrocytes in vitro, combines with cell constituents in two stages, the first almost immediate and involving tributyrinase inactivation, the second slower (more than 40 minutes) involving cholinesterase inactivation. Raising the DFP concentration increases the amount irreversibly bound, but increases even more the immediate post-transfusion elution, and DFP is unsuited for investigating erythrocyte viability of stored samples. In vivo tagging by intramuscular injection is satisfactory and normal survival curves are linear since the sample tagged has normal age distribution of cells in absence of random destruction. Here DFP32 curves are easier to interpret than Cr51 curves. In sheep, chromium elution occurs at two different rates producing a rapid initial drop followed by a slower one of about 3 per cent daily.
Random destruction alters cell age distribution. New equations are derived for cases in which this is constant both with and without chromium elution; they were applied satisfactorily to dog and sheep blood. Analysis of such curves is difficult; approximate values for random destruction rates can be obtained though not potential life spans. Chromium curves can be analyzed only with the help of DFP32 or similar curves, and yield little additional information. DFP32 and chromium can be used simultaneously to provide controls.
The Metabolism of Serum Proteins in Neonatal Rabbits
Authors: Deichmiller Maria P. , Dixon Frank J. 
Published: May 2004

1. Incorporation of S35-labeled amino acids into serum proteins has been studied in neonatal and developing rabbits. It was found that, per unit weight, neonatal rabbits synthesized only about 1/36 of the gamma globulin, 1/7 of the beta globulin, ½ of the alpha globulin, and ⅛ of the albumin that an adult synthesized. The growing rabbit developed the ability to synthesize various serum proteins at different times.
2. Plasma volumes and serum protein concentrations were determined at different times during the growth period of the rabbit. Plasma volumes were found to be 1 and ½ times larger in newborn animals than in adults, with a gradual decline to the adult level. The total serum protein concentration at birth was about 60 to 65 per cent of the adult value and gradually increased with growth as the plasma volume decreased.
3. Half-lives of homologous albumin and gamma globulin were studied. The half-life of albumin in neonates was nearly twice as long as the half-life in adults, the latter value being reached at 1 month of age. The half-life of gamma globulin in neonates was more than twice as long as the half-life in adults and reached adult values at 2 to 3 months.
4. Attempts were made to alter serum protein metabolism. Gamma globulin synthesis early in life was augmented with antigen injections.
Studies on the Nervous Regulation of the Heart Beat in Decapod Crustacea
Authors: Florey Ernst 
Published: May 2004

The effect of electrical stimulation of cardioaccelerator and cardioinhibitor nerves on the mechanically recorded heart beat of crayfish was studied. Similar experiments were performed with the lobster, Homarus americanus.
Quantitative relationships between uni- and bilateral accelerator and/or inhibitor nerve stimulation and the resulting change in frequency and amplitude of the heart beat were established.
With increasing frequency of stimulation the accelerator nerves show a relative decrease in their action, while that of the inhibitor nerves increases. It appears that left and right regulator nerves have synaptic contacts at the same areas of the postsynaptic cells within the heart ganglion. Similar results are obtained whether all impulses arrive over one, or over the other, or over both accelerator (or inhibitor) nerves; the resulting acceleration or inhibition depends strictly on the number of accelerator, or inhibitor impulses arriving at the ganglion.
The ganglion cells can adapt to the inhibitor action. This is shown to be a postsynaptic phenomenon. Adaptation to accelerator stimulation is virtually absent.
Characteristic after-effects of the accelerator and inhibitor action were observed and quantitatively evaluated.
The interpretation of the results is based on the assumption of chemical transmitter substances. It is concluded that the accelerating transmitter decays slowly while the inhibitory transmitter is inactivated relatively rapidly.
Studies on Independent Synthesis of Cytoplasmic Ribonucleic Acids in Acetabularia mediterranea
Authors: Naora Hiroto , Naora Hatsuko , Brachet Jean 
Published: May 2004

1. The RNA content of anucleate and nucleate fragments of Acetabularia has been measured. It was found that there is a net synthesis of RNA in nucleate fragments. On the other hand, the RNA content of anucleate fragments did not change significantly after enucleation.
2. Anucleate fragments, however, can readily incorporate 14C-labeled adenine, orotic acid, and carbon dioxide into their cytoplasmic RNA.
3. The results of experiments on 14CO2 incorporation into the RNA of anucleate and nucleate fragments suggest that there is a mechanism for de novo synthesis of RNA in anucleate cytoplasm.
4. In Acetabularia, 81 per cent of the cytoplasmic RNA is bound to a large granule fraction, consisting mainly of chloroplasts. Even after removal of the nucleus, RNA is synthesized in this "chloroplast" fraction. The chloroplasts are thus a major site of RNA synthesis in the cytoplasm of these algae. Synthesis of "chloroplastic" RNA, in anucleate fragments, possibly occurs at the expense of the RNA present in other fractions (microsomes and supernatant).
5. 8-Azaguanine stimulates regeneration and cap formation in anucleate fragments and does not inhibit RNA synthesis in these fragments.
Studies on the Bohr Effect of Sheep Hemoglobin
Authors: Smyth Derek G. , Battaglia Frederick C. , Meschia Giacomo 
Published: May 2004

A simple method is described for the measurement of pH changes in hemoglobin solutions on oxygenation and reduction. Data are presented establishing the absence of a Bohr effect in p-chloromercuribenzoate [PCMB] treated hemoglobin.
The influence of a number of sulfhydryl inhibitors on the Bohr effect of a hemoglobin solution is reported and an interpretation based on steric factors in the protein is proposed.
The Natural Occurrence of Ethionine in Bacteria
Authors: Fisher J. F. , Mallette M. F. 
Published: May 2004

Two unknown radioactive areas appeared after radioautography and two dimensional paper chromatography of culture medium in which Escherichia coli was grown. These materials were studied by paper chromatography and paper electrophoresis of several derivatives and identified as ethionine and ethionine sulfone, the latter an artifact. Chromatographic coincidence of the unknowns and their derivatives with authentic materials establishes the identification.
Ethionine was found in cellular extracts and in the growth media of Escherichia coli, Bacillus megaterium, Pseudomonas aeruginosa, and Aerobacter aerogenes but not in Scenedesmus, Saccharomyces cerevisiae, or bovine lymphosarcoma cells.
Ethionine was synthesized by resting E. coli cultures from radioactive sulfate and from radioactive methionine. Growing cells labeled ethionine within 1 minute after addition of radioactive sulfate to cultures. Levels of radioactivity in ethionine increased with time. No incorporation of this amino acid could be detected in the cellular proteins formed under the conditions of this study.
Effects of Temperature on the Generator and Action Potentials of a Sense Organ
Authors: Ishiko Nobusada , Loewenstein Werner R. 
Published: May 2004

Charge transfer through the receptor membrane of the nonmyelinated ending of Pacinian corpuscles is markedly affected by temperature. The rate of rise and the amplitude of the generator potential in response to a constant mechanical stimulus increase with temperature coefficients of 2.5 and 2.0 respectively. The duration of the falling phase, presumably a purely passive component, and the rise time of the generator potential are but little affected by temperature. The following interpretation is offered: Mechanical stimulation causes the conductance of the receptor membrane to increase and ions to flow along their electrochemical gradients. An energy barrier of about 16,000 cal/mole limits the conductance change. The latter increases, thus, steeply with temperature, causing both the rate of rise and the intensity of the generator current to increase.
The membrane of the adjacent Ranvier node behaves in a distinctly different manner. The amplitude of the nodal action potential is little changed over a wide range of temperature, while the durations of its rising and falling phases increase markedly. The electrical threshold of the nodal membrane is rather constant between 40 and 12°C. Below 12°C the threshold rises, and the mechanically elicited generator current fails to meet the threshold requirements of the first node. Cold block of nerve impulse initiation then ensues, although the receptor membrane still continues to produce generator potentials in response to mechanical stimulation.
Alkaline Phosphatase Content and the Effects of Prednisolone on Mammalian Cells in Culture
Authors: Cox Rody P. , MacLeod Colin M. 
Published: May 2004

The alkaline phosphatase content of different tissue culture cell lines has been shown to vary from no detectable activity to high enzyme concentration. Within the epithelial lines studied alkaline phosphatase is either constitutive or inducible. Two epithelial cell strains in which alkaline phosphatase was "absent" could be induced to develop significant amounts of the enzyme when grown in the presence of Δ1-hydrocortisone. Phosphate did not repress enzyme induction by prednisolone. Under conditions of deadaptation the induced enzyme was diluted by cell multiplication. The mouse fibroblastic L line and several human fibroblastic lines did not contain alkaline phosphatase when grown under the conditions described nor could they be induced to produce the enzyme when cultivated in medium with prednisolone.
Δ1-Hydrocortisone has other characteristic effects on established mammalian cell cultures which vary among cell lines. Human epithelial lines show reduction in cell multiplication with increase in mitotic index. The cytoplasm is increased and cell volume is nearly doubled. Mouse fibroblasts show a similar reduction in cell multiplication with a decrease in mitotic index. There is no increase in cell cytoplasm. Human fibroblast strains show no inhibition of multiplication or alteration in total cell protein when grown in medium containing prednisolone.
Antisera prepared against "negative" prednisolone-inducible human cell lines and against a positive human line inhibited alkaline phosphatase activity to an equal degree.
Dissociation and Reassociation of Bacterial Membrane Components
Authors: Rothfield L. , Weiser M. , Endo A. 
Published: May 2004

The dissociation of the phospholipid, lipopolysaccharide, and protein components of the bacterial cell envelope results in loss of enzyme activities which are normally located in the cell envelope structure and which are involved in lipopolysaccharide biosynthesis. The activity of one of these enzymes, UDP-galactose:lipopolysaccharide α,3 galactosyl transferase, can be restored by the reassociation of purified phospholipid, lipopolysaccharide, and enzyme protein. Reconstitution of activity occurs in stepwise fashion: lipopolysaccharide + phospholipid → lipopolysaccharide·phospholipid
See PDF for Equation
enzyme·lipopolysaccharide·phospholipid. The intermediates in the reaction were isolated by gradient centrifugation. The final ternary complex behaves in a similar manner to the intact cell envelope in the enzyme reaction and appears to represent the reconstitution of a portion of the membranous portion of the cell envelope.