bluuebunny/crossref_metadata_2025 huggingface dataset:
Radioisotope Uptake as a Measure of Synthesis of Messenger RNA
Authors: Nierlich Donald P.
Published: October 2006

Exogenously supplied radioactive uracil (or guanine) enters the intracellular pools of RNA precursors in
Escherichia coli
only as nucleotides are removed from these pools by net synthesis of RNA. Consequently uptake of uracil over a short period does not measure the sum of the synthesis of all forms of RNA, unstable and stable, as is often supposed. Uptake of uracil during changing conditions of growth may be influenced by changes in types of RNA's being made; under such conditions that no stable RNA is being made, the synthesis of unstable forms may be greatly underestimated.
Erythrocyte Transfer RNA: Change during Chick Development
Authors: Lee John C. , Ingram Vernon M.
Published: October 2006

Radioactive aminoacyl transfer RNA's isolated from erythrocytes in the blood of 4-day-old chick embryos and from reticulocytes of adult chickens were analyzed by chromatography on methylated albumin kieselguhr and freon columns. Embryonic and adult methionyl transfer RNA's showed qualitative and quantitative differences in both chromatographic systems. The patterns for arginyl, seryl, and tyrosyl transfer RNA's in the two cell types were similar, while the leucyl transfer RNA patterns suggested a difference.
Biochemical Genetics of Oxidative Phosphorylation
Authors: Kováč L. , Lachowicz T. M. , Slonimski P. P.
Published: October 2006

The usefulness of mutants in the unraveling of complex, highly organized, membrane-bound processes such as oxidative phosphorylation is illustrated by a study of a single recessive gene mutation in yeast, designated op
1
, which has abolished the efficiency in vivo and in vitro of oxidative phosphorylation without impairing the electron transfer.
Lambda Transition in Liquid Sulfur
Authors: Sauer G. E. , Borst L. B.
Published: October 2006

Density measurements on liquid sulfur near the transition at 160°C show a logarithmic singularity and discontinuous density. The transition shows the kinetic behavior of a zero-order reaction. The transition is expected to have a latent heat characteristic of a first-order phase transition but is of the cooperative nature associated with second-order transitions such as the lambda point in liquid helium.
Modulation of an NCAM-Related Adhesion Molecule with Long-Term Synaptic Plasticity in
Aplysia
Authors: Mayford Mark , Barzilai Ari , Keller Flavio , Schacher Samuel , Kandel Eric R.
Published: October 2006

A form of learning in the marine mollusk
Aplysia
, long-term sensitization of the gill- and siphon-withdrawal reflex, results in the formation of new synaptic connections between the presynaptic siphon sensory neurons and their target cells. These structural changes can be mimicked, when the cells are maintained in culture, by application of serotonin, an endogenous facilitating neurotransmitter in
Aplysia
. A group of cell surface proteins, designated
Aplysia
cell adhesion molecules (apCAM's) was down-regulated in the sensory neurons in response to serotonin. The deduced amino acid sequence obtained from complementary DNA clones indicated that the apCAM's are a family of proteins that seem to arise from a single gene. The apCAM's are members of the immunoglobulin class of cell adhesion molecules and resemble two neural cell adhesion molecules, NCAM and fasciclin II. In addition to regulating newly synthesized apCAM, serotonin also altered the amount of preexisting apCAM on the cell surface of the presynaptic sensory neurons. By contrast, the apCAM on the surface of the postsynaptic motor neuron was not modulated by serotonin. This rapid, transmitter-mediated down-regulation of a cell adhesion molecule in the sensory neurons may be one of the early molecular changes in long-term synaptic facilitation.
An Origin of DNA Replication and a Transcription Silencer Require a Common Element
Authors: Rivier David H. , Rine Jasper
Published: October 2006

A eukaryotic chromosomal origin of replication was identified in the yeast
Saccharomyces cerevisiae
. By several criteria, including map position, deletion analysis, and a synthetic form of saturation mutagenesis, the origin co-localized with the
HMR-E
silencer, which is a DNA element that represses transcription of the adjacent genes. A specific site within the silencer was required for both initiation of chromosomal replication and for repression of transcription. This analysis directly demonstrates that initiation of eukaryotic chromosomal replication is dependent on specific sequence elements and that a particular element can act in both initiation of chromosomal replication and regulation of transcription.
Cloning and Expression in Yeast of a Plant Potassium Ion Transport System
Authors: Sentenac Hervé , Bonneaud Nathalie , Minet Michèle , Lacroute François , Salmon Jean-Michel , Gaymard Frédéric , Grignon Claude
Published: October 2006

A membrane polypeptide involved in K
+
transport in a higher plant was cloned by complementation of a yeast mutant defective in K
+
uptake with a complementary DNA library from
Arabidopsis thaliana
. A 2.65-kilobase complementary DNA conferred ability to grow on media with K
+
concentration in the micromolar range and to absorb K
+
(or
86
Rb
+
) at rates similar to those in wild-type yeast. The predicted amino acid sequence (838 amino acids) has three domains: a channel-forming region homologous to animal K
+
channels, a cyclic nucleotide-binding site, and an ankyrin-like region.
Acyl Carrier Protein: Effects of Acetylation and Tryptic Hydrolysis on Function in Fatty Acid Synthesis
Authors: Majerus Philip W.
Published: October 2006

Acetylation of the four lysine residues and the amino group of the terminal serine residue of
Escherichia coli
acyl carrier protein has no effect on the ability of this protein to function in fatty acid synthesis. Subsequent trypsin hydrolysis resulting in complete inactivation cleaves a single arginyl peptide bond, releasing the amino terminal hexapeptide from the molecule.
Vascular Smooth Muscle: Quantitation of Cell Thickness in the Wall of Arterioles in the Living Animal in situ
Authors: Baez Silvio
Published: October 2006

The wall of microarterial vessels, in the living animal
in situ
, was examined at magnification up to × 6500 on the television screen. The optical resolution of the cell components of the wall was sufficiently clear to permit image formation and splitting for permanent recording and quantitation. Thickness of single smooth muscle cells at rest was estimated to be 2.08 microns (S.D. ± 0.24 micron) and 2.78 microns (S.D. ± 0.59 micron) by two different approaches. Changes in cell thickness during activity were also recorded and quantitated.
Myotatic Reflex: Its Input-Output Relation
Authors: Poppele R. E. , Terzuolo C. A.
Published: October 2006

The dynamic properties of the myotatic reflex and of its components were determined by a systems-analysis approach. The gain and phase relations between an applied stretch, which initiates the reflex, and the output of the primary muscle spindles, which impinge upon α-motoneurons, are not further changed by the properties of the motoneurons. The dynamic relation between motoneuron activity and the resultant muscle tension balances these changes in gain and phase; the result is a flat gain and nearly zero phase difference between stretch and tension produced by the myotatic reflex. Moreover, the distribution of activity in multiple channels extends the range in which the overall reflex is linear.
Fluid Transport and Tubular Intercellular Spaces in Reptilian Kidneys
Authors: Schmidt-Nielsen Bodil , Davis Lowell E.
Published: October 2006

Renal tubules of crocodiles, lizards, snakes, and turtles have intercellular spaces similar in type to those observed in the mammalian gall bladder, but different from those of mammalian renal tubules. The fluid movements across renal tubules of reptiles are correlated with the width of the tubular intercellular spaces. In the proximal tubules, where transport is always isosmotic, the spaces are open whenever the tubular epithelium is tranporting, but closed when no transport is taking place. In distal tubules, intercellular spaces are wide open when the osmolality of the urine is close to that of the blood, that is, when the fluid resorbed is almost isosmotic to the tubular fluid. The apical two-thirds of the intercellular spaces are closed when the urine is hypoosmotic. They are also closed when the tubules are not transporting, as in collapsed tubules or tubules poisoned with ouabain. Thus, as in the gall bladder, the open intercellular spaces appear to be found whenever there is fluid transport across the epithelium.
Gallstone of Unusual Composition: Calcite, Aragonite, and Vaterite
Authors: Sutor D. June , Wooley Susan E.
Published: October 2006

A gallstone of almost perfect octahedral symmetry was composed of a mixture of crystallites of the three polymorphous forms of calcium carbonate: calcite, aragonite, and vaterite.
Oxytocin Gene Expression in Rat Uterus
Authors: Lefebvre Diana L. , Giaid Adel , Bennett Hugh , Larivière Richard , Zingg Hans H.
Published: October 2006

The neurohypophyseal hormone oxytocin (OT) is the most potent uterotonic agent known and is used to induce labor. Yet, endogenous circulating OT appears not to participate in the induction of labor. As shown here, the finding of OT messenger RNA and peptide in the uterus suggests a solution for this paradox. During gestation, rat uterus OT messenger RNA increased more than 150-fold and, at term, exceeded hypothalamic OT messenger RNA by 70-fold. Thus, during parturition, OT may act primarily as a local mediator and not as a circulating hormone.
Lysosomal Stability during Phagocytosis of
Aspergillus flavus
Spores by Alveolar Macrophages of Cortisone-Treated Mice
Authors: Merkow Leonard , Pardo Matias , Epstein Sheldon M. , Verney Ethel , Sidransky Herschel
Published: October 2006

Control mice and those treated with cortisone were exposed to aerosols of viable spores of
Aspergillus flavus
. Fifteen to 20 minutes later, animals were killed, and alveolar macrophages were obtained by tracheobronchial lavage. Electron-microscopic examination of these cells revealed that, whereas the lysosomes of control macrophages showed extensive attraction and fusion with the phagocytic membranes surrounding spores, the lysosomes of macrophages from animals treated with cortisone revealed little, if any, interaction. This diminished lysosomal response in forming phagocytic vacuoles may be important in the subsequent development of hyphal bronchopneumonia which frequently occurs in cortisone-treated mice exposed to spores of
A. flavus
.
Thymine-Thymine Adduct as a Photoproduct of Thymine
Authors: Varghese A. J. , Wang S. Y.
Published: October 2006

A product isolated from thymine irradiated with ultraviolet light in frozen aqueous solution undergoes dehydration on heating with acids. As judged by elemental analysis, mass, ultraviolet, infrared, and nuclear magnetic resonance spectra, the most probable structures for this compound and its dehydration product, respectively, are 5-hydroxy-6-4′-[5′-methylpyrimidin-2′-one]-dihydrothymine and 6-4′-[5′-methylpyrimidin-2′-one]-thymine. Apparently, this compound is a thymine-thymine adduct and presumably is formed through the rearrangement of an initial photoproduct. Both compounds are closely related to 6-4′-[pyrimidin-2′-one]-thymine which has been isolated from acid hydrolyzates of ultraviolet-irradiated DNA and supposedly is derived from cytosine-thymine adduct. Formation of such adducts between pyrimidine bases is apparently a common photoreaction and may be important to the study of the photochemistry and photobiology of nucleic acids.
Tritiated Digoxin Binding to (Na
+
+ K
+
)-Activated Adenosine Triphosphatase: Possible Allosteric Site
Authors: Schwartz Arnold , Matsui Hideo , Laughter Arline H.
Published: October 2006

Tritiated H
3
-digoxin specifically binds to a cardiac (Na
+
+ K
+
)-activated adenosine triphosphatase. In the presence of adenosine triphosphate and other nucleoside di- and triphosphates, binding is stimulated by sodium ion, the apparent rate constant being similar to that reported for phosphorus-32 incorporation from adenosine triphosphate and for adenosine triphosphatase activity. In the presence of magnesium, manganese, inorganic phosphate, or other ions, sodium ion inhibits binding. The data support an allosteric type of sodium-potassium ion pump.
Problem of Sieve-Tube Slime
Authors: Crafts A. S.
Published: October 2006

It is proposed that sieve tubes contain a stationary, living, filamentous reticulum that persists throughout their functioning life. The filaments are about 100 to 150 angstroms in diameter and often striated. By swelling they block the pores of old sieve plates after slime has been lost from the elements. In
Cucurbita
, slime may be loosely bound to the filaments; in many species it is hydrolyzed, swept out by the assimilate stream, and eventually metabolized.
Dimethyl Sulfoxide: Interactions with Aromatic Hydrocarbons
Authors: Kocsis J. J. , Harkaway S. , Santoyo M. C. , Snyder R.
Published: October 2006

Dimethyl sulfoxide (DMSO) enhanced the hypertaurinuria produced by benzene, chlorobenzene, and toluene in rats. Undiluted DMSO was more effective than DMSO diluted with water in potentiating the toxicity of benzene in both rats and mice. Supernatants (9000
g
) prepared from livers of rats treated with DMSO 24 hours earlier metabolized more benzene than those from control rats.
Fatty Acids in Blue-Green Algae: Possible Relation to Phylogenetic Position
Authors: Holton Raymond W. , Blecker Harry H. , Stevens Timothy S.
Published: October 2006

Analyses of the lipids in five species of blue-green algae show that the fatty acids are largely the C
16
and C
18
acids. The only alga that could be grown heterotrophically, Chlorogloea, formed the triply unsaturated C
18
acid in the light but only the doubly unsaturated C
18
acid in the dark. Examination of these results and the results of others suggest that, except for one species, the more highly unsaturated acids are found in the morphologically more complex algae. The fatty acid compositions of blue-green algae are different from the fatty acid composition of the other prokaryotic organisms, the bacteria. It is speculated that the diversity of the patterns of fatty acid composition among the blue-green algae could be of phylogenetic significance.
Superconducting Phosphorus
Authors: Wittig J. , Matthias B. T.
Published: October 2006

Phosphorus, the element itself, becomes superconducting near 4.7°K and at pressures exceeding 100 kilobars. This constitutes one of the four last missing links in the proof that superconductivity is normal behavior for every truly metallic
sp
element. The three remaining ones are arsenic, sulfur, and iodine.
Secretory Immunoglobulin A: Autoantibody Activity in Gastric Juice
Authors: Goldberg Leonard S. , Shuster Joseph , Stuckey Margaret , Fudenberg H. Hugh
Published: October 2006

An immunoglobulin A of the secretory variety, present in the gastric juice of a patient with pernicious anemia, was shown to have specificity for intrinsic factor. This is the first demonstration in gastric juice of antibody activity restricted to secretory IgA; further, this is the first example of an exocrine (gastric) immune system producing an autoantibody specifically directed toward a product synthesized by that same exocrine organ.
Photoelectric and Spectroscopic Observations Related to a Possible Optical Counterpart for Pulsar CP 1919+21
Authors: Lynds R. , Maran S. P. , Trumbo D. E.
Published: October 2006

Spectroscopic observations of the two stars near the pulsar CP 1919+21 are not sufficiently conclusive to permit an identification of either object with the source of the radio pulses. However, our most extensive series of photometric observations of a region of sky near the radio source position, which region includes the brighter of the two stars, suggests an approximately sinusoidal variation. It is significant that the period of the variation is double the period of the radio pulsations.
Cyclic 3′,5′-Adenosine Monophosphate Phosphodiesterase Produced by the Slime Mold
Dictyostelium discoideum
Authors: Chang Ying-Ying
Published: October 2006

An enzyme that hydrolyzes cyclic 3′,5′-adenosine monophosphate to 5′-adenosine monophosphate was found in the culture medium of the cellular slime mold
Dictyostelium discoideum
. The enzymatic activity shows a
p
H optimum of 7.5, and magnesium is required for maximum activity. The enzyme is not inhibited by caffeine. It has a Michaelis-Menten constant of 2 × 10
-3
M
and its molecular weight is around 300,000.
Actomyosin-Like Protein Isolated from Mammalian Brain
Authors: Puszkin S. , Berl S. , Puszkin Elena , Clarke D. D.
Published: October 2006

A protein with characteristics similar to actomyosin has been isolated from whole brain of rat and cat. It is soluble in 0.6 molar potassium chloride and insoluble in 0.1 molar potassium chloride. It superprecipitates with magnesium ions and adenosine triphosphate. It has adenosine triphosphatase activity stimulated by either magnesium or calcium ions. Both superprecipitation and adenosine triphosphatase activity are inhibited by
p
-chloromercuribenzoate and Mersalyl but not by ouabain.
Visual Evoked Response Correlates of Unconscious Mental Processes
Authors: Shevrin Howard , Fritzler Dean E.
Published: October 2006

Average evoked responses and accompanying free associations elicited by subthreshold visual stimuli were studied to determine if a differential discrimination between two stimuli would be reflected in either or both of these responses. The results indicate that the effects of subliminal perception are encoded in the average evoked response and also influence the content of free associations.
A New Allotropic Form of Carbon from the Ries Crater
Authors: El Goresy A. , Donnay G.
Published: October 2006

A new allotropic form of carbon occurs in shock-fused graphite gneisses in the Ries Crater, Bavaria. The assemblage in which it occurs consists of hexagonal graphite, rutile, pseudobrookite, magnetite, nickeliferous pyrrhotite, and baddeleyite. Electron-probe analyses indicate that the new phase is pure carbon. It is opaque and much more strongly reflecting than hexagonal graphite. Measurement of x-ray diffraction powder patterns leads to cell dimensions a = 8.948 ± 0.009, c = 14.078 ± 0.017 angstroms, with a primitive hexagonal lattice.
X-ray Structures of the Sun during the Importance 1N Flare of 8 June 1968
Authors: Vaiana G. S. , Reidy W. P. , Zehnpfennig T. , VanSpeybroeck L. , Giacconi R.
Published: October 2006

High-resolution solar x-ray images were obtained with a rocket-borne grazing incidence telescope. The x-ray flare is large in extent, has fine structure, and follows a neutral magnetic line. X-ray emitting coronal links interconnect active regions. The general coronal emission at the limb and several faint regions on the disc are observed.
Vascular Injury and Lysis of Basement Membrane in vitro by Neutral Protease of Human Leukocytes
Authors: Janoff Aaron , Zeligs Joseph D.
Published: October 2006

Frozen and thawed granules of human, peripheral-blood leukocytes rapidly produce hemorrhage when injected into animal tissues. The effect is blocked by inhibitors of proteolysis. The granule extract can digest vascular basement membrane in vitro at neutral
p
H. In addition, basement membranes of blood vessels damaged in vivo by the leukocyte fraction are found to be attenuated when examined by electron microscopy. The proteases of human leukocyte granules differ in several important respects from known lysosomal cathepsins and trypsin-like esterases. Polymorphonuclear neutrophils are a major source of the neutral proteases present in circulating white cells, and release these enzymes during phagocytosis of immune complexes.
Magnetoencephalography: Evidence of Magnetic Fields Produced by Alpha-Rhythm Currents
Authors: Cohen David
Published: October 2006

Weak alternating magnetic fields outside the human scalp, produced by alpha-rhythm currents, are demonstrated. Subject and magnetic detector were housed in a multilayer magnetically shielded chamber. Background magnetic noise was reduced by signal-averaging. The fields near the scalp are about 1 × 10
-9
gauss (peak to peak). A course distribution shows left-right symmetry for the particular averaging technique used here.
Activity Coefficients of Aqueous Sodium Chloride from 15° to 50°C Measured with a Glass Electrode
Authors: Truesdell Alfred H.
Published: October 2006

Values of the mean activity coefficient of sodium chloride at 15°, 25°, 38° and 50°C were determined for aqueous NaCl solutions of 0.01 to 1.0 molal from electromotive force measurements on the cell: (sodium-sensitive glass electrode, aqueous sodium chloride, silver chloride-silver).
Argon-40: Excess in Submarine Pillow Basalts from Kilauea Volcano, Hawaii
Authors: Dalrymple G. Brent , Moore James G.
Published: October 2006

Submarine pillow basalts from Kilauea Volcano contain excess radiogenic argon-40 and give anomalously high potassium-argon ages. Glassy rims of pillows show a systematic increase in radiogenic argon-40 with depth, and a pillow from a depth of 2590 meters shows a decrease in radiogenic argon-40 inward from the pillow rim. The data indicate that the amount of excess radiogenic argon-40 is a direct function of both hydrostatic pressure and rate of cooling, and that many submarine basalts are not suitable for potassium-argon dating.
Inhibitor of Bacterial Growth Released by Human Cells in Culture
Authors: Kenny C. Paul , Sparkes Brian G.
Published: October 2006

Used medium from cultured human cells contains a factor that inhibits growth of the "less virulent" strains of pathogenic bacteria, but only retards growth of the "more virulent" strains. The factor is heat-stable, dialyzable, and unaffected by change in
p
H; it chromatographs as material of molecular weight between 700 and 1500. There is evidence that this factor is an α-ketoaldehyde attached to a carrier.
Ecological Chemistry and the Palatability Spectrum
Authors: Brower Lincoln P. , Ryerson William N. , Coppinger Lorna L. , Glazier Susan C.
Published: October 2006

A new bioassay for comparing the palatability to avian predators of monarch butterflies reared on various asclepiadaceous food plants containing cardiac glycosides indicates a palatability spectrum. The monarchs reared on one plant species are six times as emetic as those fed another, while those raised on an asclepiad which lacks cardiac glycosides are not emetic at all.
Electrotonic Spread of Dendritic Potentials in Feline Pyramidal Cells
Authors: Jacobson Stanley , Pollen Daniel A.
Published: October 2006

In pyramidal cells synaptic activation of the entire apical dendritic tree distal to the branch point of the major shaft can dominate the neuronal firing pattern. Uniform synaptic activation of distant parts of the dendritic tree (∼750 microns from the soma) would produce potential changes at the soma of 2 to 3 percent of the magnitude of the dendritic potential changes. Even these small somatic potential changes could modulate the frequency of firing of neurons depolarized close to or above firing level by more proximal synaptic inputs.
Probing Protein Stability with Unnatural Amino Acids
Authors: Mendel David , Ellman Jonathan A. , Chang Zhiyuh , Veenstra David L. , Kollman Peter A. , Schultz Peter G.
Published: October 2006

Unnatural amino acid mutagenesis, in combination with molecular modeling and simulation techniques, was used to probe the effect of side chain structure on protein stability. Specific replacements at position 133 in T4 lysozyme included (i) leucine (wt), norvaline, ethylglycine, and alanine to measure the cost of stepwise removal of methyl groups from the hydrophobic core, (ii) norvaline and
O
-methyl serine to evaluate the effects of side chain solvation, and (iii) leucine,
S
,
S
-2-amino-4-methylhexanoic acid, and
S
-2-amino-3-cyclopentylpropanoic acid to measure the influence of packing density and side chain conformational entropy on protein stability. All of these factors (hydrophobicity, packing, conformational entropy, and cavity formation) significantly influence protein stability and must be considered when analyzing any structural change to proteins.
Spectral Reflectance of Gull's Bill: Physiological and Evolutionary Implications for Animal Communication
Authors: Hailman Jack P.
Published: October 2006

The newly hatched laughing gull chick (
Larus atricilla
) begs food by pecking at the parent's dark red bill. The spectral reflectance of the bill over a range of 300 to 1200 nanometers reflects increasingly more with wavelength beginning about 575 nanometers. Because the chick shows a bimodal, true color preference in pecking, with modes at about 625 and 450 nanometers; the latter, blue peak in the spectral response curve is apparently not adapted to the natural stimulus of the parent's bill. The blue peak might thus be the result of limitations in the neural coding of color information in the chick's visual system.
Insulin Secretion from Toadfish Islet Tissue Stimulated by Pyridine Nucleotides
Authors: Watkins D. , Cooperstein S. J. , Dixit P. K. , Lazarow A.
Published: October 2006

The addition of glucose stimulated release of insulin from the isolated islet tissue of the toadfish incubated in vitro. Reduced nicotinamide-adenine dinucleotide also stimulated insulin release, whereas the oxidized form had no effect. Both oxidized and reduced nicotinamide-adenine dinucleatide phosphate stimulated insulin release, but the reduced form was significantly more effective.
Sterols: Isolation from a Blue-Green Alga
Authors: de Souza Noel J. , Nes William R.
Published: October 2006

A crystalline mixture of sterols was isolated from the filamentous blue-green alga
Phormidium luridum
. The mixture consisted of unsaturated 24-ethylcholesterols possessing Δ
7
-, Δ
5,7
-, and Δ
5
-bonds together with their Δ
22
-derivatives and a small amount of cholesterol. The major component was 24-ethyl-Δ
7
-cholestenol. Squalene and phytol were also evident.
Estrogenic Activity of
o
,
p
′-DDT in the Mammalian Uterus and Avian Oviduct
Authors: Bitman Joel , Cecil Helene C. , Harris Susan J. , Fries George F.
Published: October 2006

When rats and birds were treated with
o
,
p
′-DDT, their reproductive tissues exhibited the same response as when they were treated with estrogen. Weight, water content, glycogen, and RNA increased in uteri and oviducts of rats, chickens, and quail receiving
o
,
p
′-DDT; p,
p
′-DDT produced little if any response. The
o
,
p
′-DDT did not accumulate in the reproductive or adipose tissues to a greater extent than
p
,
p
′-DDT.
Uridylate Kinase Activity: Effect of Isoproterenol
Authors: Malamud Daniel , Baserga Renato
Published: October 2006

Isoproterenol stimulates cell proliferation in mouse salivary glands. Prior to the stimulation of DNA synthesis,
3
H-uridine incorporation into RNA is decreased. This decreased incorporation results from a depression of uridylate kinase activity.
Evoked Release of Norepinephrine and Serotonin from Brain Slices: Inhibition by Lithium
Authors: Katz Richard I. , Chase Thomas N. , Kopin Irwin J.
Published: October 2006

Slices of mammalian brain accumulate H
3
-norepinephrine and H
3
-serotonin when incubated in a physiologic medium containing these tritiated monoamines. When these tissues are subjected to mild electrical stimulation of short duration, which is associated with depolarization of nerve membranes, a striking increase in the rate of efflux of the exogenous labeled monoamines occurs. Stimulation-induced release of both labeled monoamines is diminished by the presence of lithium ions in the perfusing medium; related monovalent cations had no such effect. Evoked release from slices of brain from animals treated intraperitoneally with lithium chloride for 3 days was also reduced.
Monocular Compared to Binocular Depth Perception in Human Infants
Authors: Walk Richard D.
Published: October 2006

Human infants were made temporarily monocular with an eye patch. They performed like binocular infants on the visual cliff at visual depths of 25 centimeters or more. At a visual depth of 12.7 centimeters infants younger than 9 months of age revealed a monocular weakness by turning toward the uncovered eye.
Ouabain Hypoglycemia: Insulin Mediation
Authors: Triner L. , Killian Paul , Nahas G. G.
Published: October 2006

The fall in blood sugar occurring during infusion of ouabain (1 microgram per kilogram per minute for a 60-minute period) in dogs is accompanied by an increased uptake of glucose and potassium by the liver. Concurrently, plasma insulin in the portal blood increases significantly. This increase appears to be a result of increased insulin secretion caused by ouabain.
Photograph of a Close Lightning Flash
Authors: Orville Richard E.
Published: October 2006

A lightning flash has been photographed striking a European ash tree at a distance of 60 meters. The tree sustained no external physical damage. The probability of obtaining this photograph is estimated to be 10
-3
, or once in 1000 years.
Serum Copper Alteration after Ingestion of an Oral Contraceptive
Authors: O'Leary James A. , Spellacy William N.
Published: October 2006

Changes in the concentration of copper in the serum after administration of an oral contraceptive were determined with atomic absorption spectrophotometry. Statistically significant (
P
= .001) increases were observed in all volunteers.
Pollen Grains in Lake Sediments: Redeposition Caused by Seasonal Water Circulation
Authors: Davis Margaret B.
Published: October 2006

Annual pollen deposition per unit area measured in sediment traps is two to four times greater than deposition measured in surface sediment cores. The difference is due to repeated redeposition of pollen from the sediment surface during seasons of water circulation. This process reduces variations in the percentages of different pollen types in sediment, but causes differences in the total amount of pollen accumulated in various parts of the lake basin.
Structure of Human Serum Lipoproteins: Nuclear Magnetic Resonance Supports a Micellar Model
Authors: Steim Joseph M. , Edner Orville J. , Bargoot Frederick G.
Published: October 2006

High-resolution proton nuclear magnetic resonance spectra of low- and high-density lipoproteins from human serum closely resemble those of dispersions of lipoprotein lipids in water. Linewidths of hydrocarbon proton absorptions are not increased in the lipoproteins. In contrast, apolar binding of lysolecithin on serum albumin causes extensive line-broadening and an upfield chemical shift of the hydrocarbon proton resonances of lysolecithin. The results are consistent with a predominantly micellar structure for the lipoproteins rather than with extensive hydrophobic association of lipid and protein.
Pattern Perception: Integrating Information Presented in Two Modalities
Authors: Handel Stephen , Buffardi Louis
Published: October 2006

Subjects were required to organize and identify temporal patterns composed of either (i) two stimuli in one modality; (ii) two stimuli in each of two modalities, with the pattern alternately presented in the two modalities; or (iii) one stimulus in each of two modalities. Patterns (i) and (iii) are organized as structured patterns, but (ii) is organized by modality, not by pattern structure. When elements of a pattern appear in two modalities, the auditory-tactual combination produces the poorest performance.
Mössbauer Investigation of Shocked and Unshocked Iron Meteorites and Fayalite
Authors: Lafleur L. D. , Goodman C. D. , King E. A.
Published: October 2006

Mössbauer spectra of several iron meteorites have been measured by a resonant scattering technique rather than by the conventional transmission method, thereby eliminating the necessity for the preparation of thin samples. No significant differences were observed in the spectra of specimens of mechanically deformed, shocked, and unshocked iron meteorites, nor in the absorption spectra of artificially shocked and unshocked fayalite.
Allografts in Genetically Defined Rats: Difference in Survival between Kidney and Skin
Authors: White Edward , Hildemann W. H.
Published: October 2006

Although skin allografts from inbred donors of the Fisher strain to inbred male Lewis recipients regularly show acute rejection within 12 days, orthotopic kidney allografts between untreated animals, in this same combination of strains, usually remain functionally intact for longer than 100 days. Since such renal allografts persist despite previous or concomitant rejection of skin allografts, neither acquired tolerance nor nonspecific immunosuppression can explain the surprisingly prolonged kidney survival. Many factors appear to be responsible for the disparate survival times observed. Tentatively, these factors are (i) antigenic differences between kidney and skin, (ii) intervention of immunological enhancement, and (iii) physiological differences in vulnerability between kidney and skin.
Local Anesthetics: Effect of
p
H on Activity
Authors: Ritchie J. M. , Ritchie Brenda R.
Published: October 2006

Lidocaine and dibucaine are more effective in neutral than in alkaline solution when tested on the nonmyelinated fibers of the desheathed vagus nerve of the rabbit. Procaine, however, is more effective in alkaline solution. The activity of benzocaine is unaffected by
p
H. Both the charged and uncharged forms of local anesthetics thus seem capable of blocking conduction.
Affinity Site Labeling of a Mouse Myeloma Protein Which Binds Dinitrophenyl Ligands
Authors: Metzger Henry , Potter Michael
Published: October 2006

A mouse myeloma protein of the immunoglobulin A class, which specifically binds dinitrophenyl ligands, has been successfully affinity labeled (site-directed labeling) with several diazonium reagents, leading to inactivation of the combining sites. The labeling reagents reacted only with tyrosine residues of light chain origin. The 7
S
subunit of the myeloma protein appears to contain only one reactive site.
Pulsating Radio Sources near the Crab Nebula
Authors: Staelin David H. , Reifenstein Edward C.
Published: October 2006

Two new pulsating radio sources, designated NP 0527 and NP 0532, were found near the Crab Nebula and could be coincident with it. Both sources are sporadic, and no periodicities are evident. The pulse dispersions indicate that 1.58 ± 0.03 and 1.74 ± 0.02 × 10
20
electrons per square centimeter lie in the direction of NP 0527 and NP 0532, respectively.
Chance and Statistical Significance in Protein and DNA Sequence Analysis
Authors: Karlin Samuel , Brendel Volker
Published: October 2006

Statistical approaches help in the determination of significant configurations in protein and nucleic acid sequence data. Three recent statistical methods are discussed: (i) score-based sequence analysis that provides a means for characterizing anomalies in local sequence text and for evaluating sequence comparisons; (ii) quantile distributions of amino acid usage that reveal general compositional biases in proteins and evolutionary relations; and (iii)
r
-scan statistics that can be applied to the analysis of spacings of sequence markers.
Haploid Plants from Pollen Grains
Authors: Nitsch J. P. , Nitsch C.
Published: October 2006

A method is presented by which hundreds of haploid plants of various species of
Nicotiana
can be raised from pollen grains. Stamens should be excised when pollen grains have been individualized, but are still uninucleate and free of starch. When grown in vitro on a relatively simple medium, some pollen grains proliferate into embryo-like structures which develop in stages similar to those of zygotic embryos. The plantlets mature and flower profusely, but do not set seed.
Human C′3: Evidence for the Liver as the Primary Site of Synthesis
Authors: Alper Chester A. , Johnson A. Myron , Birtch Alan G. , Moore Francis D.
Published: October 2006

The liver is the primary, if not sole, site of synthesis of the third component of human complement, as shown by a change in the recipient from C′3 FS
0.6
to C′3 SS, the donor type, following homotransplantation of the liver.
Calcium Current and Activation of Contraction in Ventricular Myocardial Fibers
Authors: Reuter Harald , Beeler George W.
Published: October 2006

In thin bundles of dog ventricular myocardium, a slow inward current (distinct from the sodium inward current) could be recorded under voltage-clamp conditions. This inward current was influenced by changes in external calcium concentration, but it was not dependent on external sodium concentration. Therefore, this current which contributes an appreciable amount of charge transfer during the plateau of the action potential, is carried by calcium ions. In sodium-free solution, the flow of calcium ions into the fiber is directly related to activation of contraction. In sodium-containing solution, however, calcium inward current serves primarily to fill up some intracellular stores from which calcium can be released by moderate depolarization.
Solubility in Water of Normal C
9
and C
10
, Alkane Hydrocarbons
Authors: McAuliffe Clayton
Published: October 2006

A new method for equilibrating water containing alkane hydrocarbons with a gas phase and analyzing the gas for hydrocarbon content by gas chromatography extends analytical sensitivity to better than 0.1 part per billion. The solubilities at 25°C of the normal C
9
(220 parts per billion) and C
10
(52 parts per billion) alkanes decrease with increasing carbon number. A discontinuity occurs at the normal C
11
alkane, probably because of a change from true solubility (molecular dispersion) to accommodation (aggregation).
Punishment by Response-Contingent Withdrawal of an Imprinted Stimulus
Authors: Hoffman Howard S. , Stratton James W. , Newby Valerie
Published: October 2006

Newly hatched ducklings were exposed to a moving, imprinted stimulus; if they followed it, the stimulus was withdrawn briefly. The tendency to follow gradually declined during punishment periods, but it returned to prepunishment amounts when punishment terminated. This finding attests to the efficacy of withdrawal of reinforcement as a technique for behavioral control.
Mineral Source and Transport in Waters of the Gulf of Mexico and Caribbean Sea
Authors: Jacobs Marian B. , Ewing Maurice
Published: October 2006

Mineral particles suspended in the Gulf of Mexico and Caribbean Sea were analyzed in relation to clay mineral distributions in bottom sediments, to sedimentation processes active in the region, and to the prevailing currents. Circulation in the upper layers of water flowing from the Caribbean, carrying a micaceous-rich mineral assemblage, has exercised an influence on mineral transport into the Gulf of Mexico, different from the montmorillonite-rich load delivered by the Mississippi River. Particulate matter, suspended in North Atlantic water and Amazon River discharge, enters the Caribbean through the Lesser Antilles and contributes to the detrital mineral content of Caribbean water, as does that carried by the wind.
Metallic Colloids in Molten Salts
Authors: Kohn Harold W. , Willmarth Ted E.
Published: October 2006

Gold, silver, and silver iodide sols were prepared in mixed nitrate melts. Electron micographs of the gold and silver sols show particles smaller than 1 micron. The gold sols exhibit conventional absorption and scattering spectra. Both gold and silver sols show unusual stability.
Nitrification: Importance to Nutrient Losses from a Cutover Forested Ecosystem
Authors: Likens Gene E. , Bormann F. H. , Johnson Noye M.
Published: October 2006

The nitrate concentration (weighted average) in stream water from an experimentally deforested watershed increased from 0.9 milligram per liter before removal of the vegetation to 53 milligrams per liter 2 years later. This nitrate mobilization, presumably due to increased microbial nitrification, was equivalent to all of the other net cationic increases and anionic decreases observed in the drainage water.
Radiosensitivity and Rate of Cell Division: "Law of Bergonié and Tribondeau"
Authors: Haber Alan H. , Rothstein Barbara E.
Published: October 2006

The rate of cell division decreases as tobacco leaves grow, and older leaves grow without any cell divisions. Disks were cut from leaves having differing degrees of cell division at various developmental stages. In the chlorenchyma, the induced susceptibility to photodestruction of chloroplasts was used to measure sensitivity to gamma radiation as a function of the rate of cell division. The same biological effect can thereby be studied both in dividing and in nondividing tissues of the same morphological and physiological cell types. The radiosensitivities were approximately the same, irrespective of the extent of cell divisions.
Gas Vacuole Development in a Blue-Green Alga
Authors: Waaland J. Robert , Branton Daniel
Published: October 2006

De novo
production of gas vacuoles can be induced in the blue-green alga
Nostoc muscorum
by transferring the cells from a defined medium to distilled water. The unusual ultrastructure of the gas vacuole membranes permits their easy recognition when specimens are prepared for electron microscopy by freeze-etching. The youngest gas vacuoles are biconical organelles; 48 hours after induction the gas vacuoles reach their maximum observed length when they are cylinders (1.5 by 0.1 μ) with cornical ends.
Surfacing of Pacific Equatorial Undercurrent: Direct Observation
Authors: Jones James H.
Published: October 2006

Measurements of current speed and direction from the sea surface to below 400 meters made on the equator in the eastern Pacific in April 1968 indicate that the Equatorial Undercurrent extends from 300 meters to the sea surface. These measurements, when compared with previous observations, indicate that eastward motion at the surface is a result of surfacing of the undercurrent caused by a release of the surface wind stress.
Adsorption of Alkyl Trimethylammonium Chlorides at a Porous Glass-Potassium Chloride Solution Interface
Authors: Hersh Leroy S.
Published: October 2006

The adsorption of dodecyl, tetradecyl, hexadecyl, and octadecyl trimethylammonium chlorides at an interface between porous glass and potassium chloride solution has been characterized by measurements of membrane potentials. The specific potential φ is 0.97
k
T
per methylene group (where
k
is the Boltzmann constant and
T
is the absolute temperature) or 580 calories per mole at 23°C.
Homing in the Ant
Cataglyphis bicolor
Authors: Wehner Rudiger , Menzel Randolf
Published: October 2006

Cataglyphis bicolor
, an ant widely distributed in North Africa and the Near East, orient to the sun as well as to visual patterns of the environment. These two mechanisms can be separated. Foraging ants (hunters) orient to terrestrial cues as long as possible, and only after these have become ineffective do they switch over to the menotactical sun orientation. In the digging individuals, however, the visual knowledge of locality is significantly inferior to that of the hunters. Diggers vary considerably in size, but hunters belong to the largest size group. In addition, the largest and smallest individuals orient differently toward black and white areas and stripe patterns.
Glycosphingolipids with Lewis Blood Group Activity: Uptake by Human Erythrocytes
Authors: Marcus Donald M. , Cass Louise E.
Published: October 2006

The Lewis blood group antigens of the human erythrocyte are acquired from plasma and not synthesized
in situ
. Although assumed previously to be glycoproteins, the Lewis antigens in plasma are glycosphingolipids which are taken up by the erythrocyte membrane from lipoproteins or from aqueous dispersions.
Neuronal Controls of a Behavioral Response Mediated by the Abdominal Ganglion of
Aplysia
Authors: Kupfermann I. , Kandel E. R.
Published: October 2006

Tactile stimulation of the siphon and mantle shelf in
Aplysia
causes a characteristic withdrawal response of the external organs of the mantle cavity. A similar response also occurs spontaneously. Both responses are mediated by the abdominal ganglion and therefore provide an opportunity for correlating cellular functioning and behavior in a relatively simple and well-studied neuronal system. The withdrawal responses are controlled by five identified motor cells which receive two types of synaptic inputs. One set of excitatory connections, activated by tactile stimulation of the siphon and mantle shelf, mediates the defensive withdrawal reflex. A second set of connections is activated by a spontaneous burst of activity in a group of closely coupled interneurons which are excitatory to some of the motor cells and inhibitory to the others. This second set of connections mediates the spontaneous withdrawal response. These two inputs can therefore switch the same population of motor cells from a simple reflex to a more complex, internally organized response.
Circadian Rhythm in Mammalian Body Temperature Entrained by Cyclic Pressure Changes
Authors: Hayden Page , Lindberg Robert G.
Published: October 2006

A 24-hour cycle of pressure (1.0 to 1.09 atmospheres) can act as a zeitgeber to entrain the endogenous circadian rhythm of body temperature in pocket mice (
Perognathus longimembris
) under constant conditions of environmental temperature and light.
LSD: Autoradiographic Study on the Placental Transfer and Tissue Distribution in Mice
Authors: Idänpään-Heikkilä Juhana E. , Schoolar Joseph C.
Published: October 2006

14
C-lysergic acid diethylamide administered intravenously passed in a few minutes from the blood into the tissues. In addition to the brain, the adrenals, hypophysis, kidneys, liver, and lungs showed the highest uptake, much higher than the blood concentration. Excretion into the bile started immediately; this was the most important elimination route. In the early stage of pregnancy, 2.5 percent (and in the late stage, 0.5 percent) of the radioactive dose passed the placental barrier into the fetus in 5 minutes. Over 70 percent of this fetal radioactivity was unchanged
14
C-lysergic acid diethylamide.
Carbon Monoxide-Induced Arterial Hypoxemia
Authors: Brody Jerome S. , Coburn Ronald F.
Published: October 2006

Inhalation of carbon monoxide produces an increase in the alveolar to arterial oxygen gradient in the presence of veno-arterial shunts or ventilation-perfusion imbalance but has no such effect in normal subjects. The increase in the alveolar to arterial oxygen gradient with rising concentrations of carboxyhemoglobin results from changes induced by carbon monoxide in the shape of the oxyhemoglobin dissociation curve.
3,4-Dihydroxyproline: A New Amino Acid in Diatom Cell Walls
Authors: Nakajima Tadashi , Volcani B. E.
Published: October 2006

An analog of proline, 2,3-
cis
-3,4-
trans
-3,4-dihydroxy-L-proline, was found in the cell walls of the eight species of diatoms studied and was isolated from the proteinaceous material of the wall of
Navicula pelliculosa
. The properties of this substance are described; its structure was confirmed by nuclear magnetic resonance spectros-copy.
Cartilaginous Dermal Scales in Cephalopods
Authors: Person Philip
Published: October 2006

Epidermal scales of the squid
Cranchia scabra
are composed of tissue which stains metachromatically with toluidine blue, and which is similar in appearance to hyaline cartilage.
Synaptic Vesicles in Electron Micrographs of Freeze-Etched Nerve Terminals
Authors: Moor H. , Pfenninger K. , Akert K.
Published: October 2006

Freeze-etched neuropil of the cat subfornical organ was examined with the electron microscope for synaptic vesicles. Round vesicles were found exclusively in both unfixed and aldehyde-fixed specimens. Range of diameters and histograms failed to differ significantly between freeze-etched and conventionally prepared material. The mode of distribution of diameters was approximately 500 angstroms. Round stomata (approximately 350 angstroms in diameter) were found at the outer surface of the plasmalemma of nerve terminals; they are interpreted as pinocytotic vesicles.