bluuebunny/crossref_metadata_2025 huggingface dataset:
Cypridina
Bioluminescence: Light-Emitting Oxyluciferin-Luciferase Complex
Authors: Shimomura Osamu , Johnson Frank H. , Masugi Takashi
Published: October 2006

Fluorescence of
Cypridina oxyluciferin
is greatly enhanced when it is bound to luciferase; the spectrum is thereby shifted, so that it corresponds precisely to the emission spectrum characteristic of the bioluminescent oxidation of luciferin. Thus the oxyluciferin-luciferase complex is the light-emitter. The binding is equimolar, with dissociation constant K
D
equal to 3 × 10
-7
mole per liter. The molecular weight of the luciferase, according to three different methods, is between 52,000 and 57,000; molecular activities of luciferase for the bioluminescence reaction and for the hydrolysis of oxyluciferin are 1600 and 2 per minute, respectively.
Maturation of Renal Organic Acid Transport: Substrate Stimulation by Penicillin
Authors: Hirsch G. H. , Hook J. B.
Published: October 2006

Renal
p
-aminohippurate transport in rabbits increased rapidly from birth to 4 weeks of age and then declined to that observed in adults. Penicillin administration to pregnant does or newborn rabbits stimulated the developing transport system, but did not increase the peak observed at 4 weeks. Therefore the continued presence of substrate (penicillin) during development significantly enhances the rate of maturation.
Dependence of Kidney Morphogenesis on the Expression of Nerve Growth Factor Receptor
Authors: Sariola Hannu , Saarma Mart , Sainio Kirsi , Arumäe Urmas , Palgi Jaan , Vaahtokari Anne , Thesleff Irma , Karavanov Alexander
Published: October 2006

Nerve growth factor receptor (NGFR) serves as the binding site for the neurotrophic growth factors. Although NGFR has been found in several embryonic tissues outside the nervous system, the function of NGFR in embryogenesis of non-neuronal organs remains unknown. NGFR is transiently synthesized by embryonic rat kidney and disappears from nephrons upon their terminal differentiation. Anti-sense oligonucleotide inhibition of NGFR expression inhibits kidney morphogenesis. Therefore, NGFR is required not only for development of the nervous system, but also for differentiation of the kidney tubules.
Brain Lesions in an Infant Rhesus Monkey Treated with Monosodium Glutamate
Authors: Olney John W. , Sharpe Lawrence G.
Published: October 2006

In an infant rhesus monkey brain damage resulted from subcutaneously administered monosodium glutamate. Although a relatively high dose of monosodium glutamate was used, the infant was asymptomatic for a 3-hour observation period during which time hypothalamic neurons were undergoing a process of acute cell death. With the electron microscope it was observed that dendrites and cell bodies of neurons are the tissue components primarily affected in brain damage induced by monosodium glutamate.
Seawater Teleosts: Evidence for a Sodium-Potassium Exchange in the Branchial Sodium-Excreting Pump
Authors: Maetz J.
Published: October 2006

The net sodium extrusion rate by the gill of the seawater-adapted euryhaline flounder is identical to the potassium influx. The excretion of sodium is blocked in K
+
-free seawater solutions. The instantaneous sodium outflux readjustment pattern of flounders transferred from seawater to solutions of various sodium chloride or potassium chloride concentrations is consistent with the hypothesis of a linkage between Na
+
outflux and K
+
influx through a common exchange carrier. External Na
+
and K
+
compete for this common carrier. It is suggested that the exchange diffusion mechanism (linkage of sodium influx and outflux) and the high internal sodium turnover rate which characterizes all seawater teleosts are the results of this competitive process. The sodium-potassium dependent adenosine triphosphatase system occurring in the gill of the seawater teleosts may play a central role in this sodium-potassium exchange pump.
Trypsin and Papain Covalently Coupled to Porous Glass: Preparation and Characterization
Authors: Weetall Howard H.
Published: October 2006

Trypsin and papain have been covalently linked to porous glass particles. The resulting insolubilized enzymes show increased thermal stability and can be employed for extended periods of time without loss of activity.
Masking of the Aggregation Pheromone in
Dendroctonus pseudotsugae
Hopk.
Authors: Rudinsky J. A.
Published: October 2006

The pheromone mask released by female
Dendroctonus pseudotsugae
Hopk. after the male stridulates stops aggregation of beetles in flight, but not arrestment of males, in an interaction of chemically and sonically induced behavior. This masking is viewed as a mechanism for survival through the regulation of attack and as a critical part of premating behavior.
Membranous Structures Associated with Translation and Transcription of Poliovirus RNA
Authors: Caliguiri Lawrence A. , Tamm Igor
Published: October 2006

Poliovirus RNA and proteins are synthesized in association with distinct membranous structures that were separated by means of isopycnic centrifugation of cytoplasmic extracts in discontinuous sucrose-density gradients. Viral RNA is replicated in a structure that contains rapidly labeled replicative intermediate RNA and viral RNA polymerase associated with the smooth membrane fraction. In sucrose gradients this viral RNA replication complex is distributed at densities in the range of 1.12 to 1.18 grams per cubic centimeter. Viral proteins are synthesized on polyribosomes bound to membranes and sediment with polyribosomes at densities of less than 1.25 grams per cubic centimeter.
Amino Acid Uptake by Kidney and Jejunal Tissue from Dogs with Cystine Stones
Authors: Holtzapple Philip G. , Bovee Kenneth , Rea Claire F. , Segal Stanton
Published: October 2006

Cystine and lysine accumulation in vitro in intestinal and renal tissue was studied in eight dogs that form cystine stones. Under conditions which demonstrate in vitro defects in tissue obtained from humans with cystinuria, normal amino acid accumulation occurred in six dogs with the canine disorder. Normal amino acid uptake in tissue and the demonstration of normal to minimum increases in excretion of lysine suggest that the canine disorder is not similar to the human syndrome.
Three-Dimensional Structures of the Ligand-Binding Domain of the Bacterial Aspartate Receptor with and Without a Ligand
Authors: Milburn Michael V. , Privé Gilbert G. , Milligan Daniel L. , Scott William G. , Yeh Joanne , Jancarik Jarmila , Koshland Daniel E. , Kim Sung-Hou
Published: October 2006

The three-dimensional structure of an active, disulfide cross-linked dimer of the ligand-binding domain of the "
Salmonella typhimurium
aspartate receptor and that of an aspartate complex have been determined by x-ray crystallographic methods at 2.4 and 2.0 angstrom (Å) resolution, respectively. A single subunit is a four-α-helix bundle with two long amino-terminal and carboxyl-terminal helices and two shorter helices that form a cylinder 20 Å in diameter and more than 70 Å long. The two subunits in the disulfide-bonded dimer are related by a crystallographic twofold axis in the apo structure, but by a noncrystallographic twofold axis in the aspartate complex structure. The latter structure reveals that the ligand binding site is located more than 60 Å from the presumed membrane surface and is at the interface of the two subunits. Aspartate binds between two α helices from one subunit and one α helix from the other in a highly charged pocket formed by three arginines. The comparison of the apo and aspartate complex structures shows only small structural changes in the individual subunits, except for one loop region that is disordered, but the subunits appear to change orientation relative to each other. The structures of the two forms of this protein provide a step toward understanding the mechanisms of transmembrane signaling.
Mechanochemical Turbine: A New Power Cycle
Authors: Sussman M. V. , Katchalsky A.
Published: October 2006

A basic thermodynamic cycle for the production of mechanical power from materials that may be made to contract forcibly and reversibly is described. The cycle differs from existing mechanical power cycles which generally employ expanding fluid as working substances. A "contraction turbine" operating on this cycle has been devised, which has collagen fiber as its working substance and salt solution as fuel and produces mechanical work directly from chemical free energy. Direct conversion of chemical to mechanical energy is routinely effected in muscle but not in usual man-made engines.
Uranium-Thorium-Lead Isotope Relations in Lunar Materials
Authors: Silver Leon T.
Published: October 2006

The lead isotopic compositions and uranium, thorium, and lead concentrations have been measured on six samples of material from the Sea of Tranquillity. The leads are moderately to very radiogenic; the initial lead concentrations are very low; the uranium and thorium levels are 0.26 to 0.88 and 0.87 to 3.35 parts per million, respectively. The Th/U ratios cluster about a 3.6 value. Apparent ages calculated for four rocks are 4.1 to 4.2 × 10
9
years. Dust and breccia yield apparent ages of 4.60 to 4.63 × 10
9
years. The uranium-lead ages are concordant, or nearly so, in all cases. The lunar surface is an ancient region with an extended record of events in the early history of the solar system. The discrepancy between the rock ages and dust ages poses a fundamental question about rock genesis on the moon.
Rubidium-Strontium Chronology and Chemistry of Lunar Material
Authors: Compston William , Arriens Pieter A. , Vernon Michael J. , Chappell Bruce W.
Published: October 2006

Igneous lunar rocks divide into two chemical types, probably representing two rock units. They form separate close groups on the isochron diagram; no total rock age is valid unless the rocks are cogenetic. Mineral isochrons prove that one type has an age of 3.80 ± 0.11 billion years, equal to the line joining total-rock groups, and the initial ratio of strontium-87 to strontium-86 of both types is close to 0.6994. Soil and breccias chemically resemble a mixture of the two igneous types, with a superimposed variation of mineral components, plus a small transferred component rich in nickel, copper, zinc, and possibly strontium-87.
Petrologic History of Moon Suggested by Petrography, Mineralogy, and Crystallography
Authors: Anderson A. T. , Crewe A. V. , Goldsmith J. R. , Moore P. B. , Newton J. C. , Olsen E. J. , Smith J. V. , Wyllie P. J.
Published: October 2006

Opaque mineral compositions indicate that the fugacity of oxygen is approximately 10
-13
(earth basalts, 10
-10
). Experiments under reducing conditions suggest that the crystallization range is approximately 1140° to 1070°C. Iron-rich pyroxmangite, fayalite, and hedenbergite occur in microgabbro. Ferropseudobrookite rimmed by ilmenite containing rutile and Cr-spinel lamellae occurs in ferrobasalt. Plagioclase vitrophyres in breccia can explain highland Surveyor VII analysis. We suggest crystal-liquid differentiation of out-gassed convecting moon with growing Fe-rich core, olivine-pyroxene mantle, plagioclase-rich dynamic crust underlain by nonspherical, inversely stratified ferrobasalt. Impact-breaking or convection-thrusting of crust releases fraction rich in Fe and Ti. Scanning electron microscopy of glass balls reveals minute depressions consistent with micrometeorite impact.
Cytogenetic Studies with Cyclamate and Related Compounds
Authors: Stoltz D. R. , Khera K. S. , Bendall R. , Gunner S. W.
Published: October 2006

Cyclamate, cyclohexylamine,
N
-hydroxycyclohexylamine, and dicyclohexylamine can induce chromosomal damage in human leukocyte cultures.
Histochemical Abnormalities of Skeletal Muscle in Patients with Acute Psychoses
Authors: Engel W. King , Meltzer Herbert
Published: October 2006

In 29 acutely psychotic patients (mostly schizophrenic), histochemical abnormalities of a myopathic type were demonstrated in skeletal muscle biopsies from 13 and were generally correlated with elevation of the "muscle" type isoenzymes of creatine phosphokinase in the patients' serum. The incidence was much higher than found in normal controls, hospitalized neurotic psychiatric patients, or parents of acutely psychotic patients. A diazo-coupling type of "alkaline phosphatase" reaction was particularly useful in identifying abnormal muscle fibers.
Hominid Phylogeny and Immunology: A Critical Appraisal
Authors: Read Dwight W. , Lestrel Pete E.
Published: October 2006

Although there seems to be a regular relation of protein change versus time via an exponential equation of the form ID =

e
kt

, nevertheless, examination of the data indicates that such an exponential fit may be premature. Two other models, ID =
kt
+
b
and ID =

bt
k

+
c
represent better fits. Without better data none of the models appears convincing.
Activation of Early Gene Expression in T Lymphocytes by Oct-1 and an Inducible Protein, OAP
40
Authors: Ullman Katharine S. , Flanagan W. Michael , Edwards Cynthia A. , Crabtree Gerald R.
Published: October 2006

After antigenic stimulation of T lymphocytes, genes essential for proliferation and immune function, such as the interleukin-2 (IL-2) gene, are transcriptionally activated. In both transient transfections and T lymphocyte-specific in vitro transcription, the homeodomain-containing protein Oct-1 participated in the inducible regulation of transcription of the IL-2 gene. Oct-1 functioned in this context with a 40-kilodalton protein called Oct-1-associated protein (OAP
40
). In addition to interacting specifically with DNA, OAP
40
reduced the rate of dissociation of Oct-1 from its cognate DNA-binding site, suggesting that a direct interaction exists between Oct-1 and OAP
40
.
Mouse Mammary Tumors: Alteration of Incidence as Apparent Function of Stress
Authors: Riley Vernon
Published: October 2006

Eighty to 100 percent of female mice of the C3H/He strain carrying the Bittner oncogenic virus usually develop mammary tumors within 8 to 18 months after birth when studied under the usual housing and experimental conditions. By subjecting various groups of such mice to environmental circumstances providing different degrees of chronic stress, mammary tumor incidence at 400 days was modified, with incidences ranging from 92 percent under stress to 7 percent in a protected environment. The data suggest that moderate chronic or intermittent stress may predispose such mice to an increased risk of mammary carcinoma, possibly through a resultant compromise of their immunological competence or tumor surveillance system, and that adequate protection from physiological stress may reduce mammary tumor occurrence in mice.
Activation of Proto-Oncogenes: an Immediate Early Event in Human Cytomegalovirus Infection
Authors: Boldogh Istran , AbuBakar Sazaly , Albrecht Thomas
Published: October 2006

A rapid increase in the RNA levels of the proto-oncogenes c-
fos
, c-
jun
, and c-
myc
was detected after human cytomegalovirus infection. Neither inactivation of viral infectivity with ultraviolet irradiation (with or without psoralen), nor inhibition of translation with cycloheximide or anisomycin adversely affected the enhanced expression of proto-oncogenes, even though these treatments substantially reduced or eliminated the detection of immediate early viral antigens. The increase in the RNA levels of the proto-oncogenes was prevented in the presence of α-amanitin or actinomycin D. Thus, expression of these oncogenes appears to be induced by events occurring before the onset of viral protein synthesis, perhaps by the interaction of viral particles with the cell surface.
The Biochemical Basis of the Fungus-Attine Ant Symbiosis
Authors: Martin Michael M.
Published: October 2006

The natural history of the fungus-growing ants provides a spectacular example of a symbiotic association of two very different types of organisms. An anthropomorphic description is difficult to resist. The ants are efficient and industrious farmers. Their single crop is a fungus, grown on a substrate of leaves in carefully fertilized, well-tended gardens. Virtually every facet of the ants' behavior and life cycle has been shaped by their association with the fungus they culture. A characteristic feature of the ants' gardening technique is the application of their fecal material to the garden and to substrate being prepared for incorporation into the garden. We have established the biochemical significance of this behavior. The fecal material contains proteolytic enzymes which compensate for a deficiency of such enzymes in the fungus. In addition, the nitrogenous components in the fecal material facilitate the initial growth of the fungus. In biochemical terms, then, one can say that the ants contribute their enzymatic apparatus to degrade protein and the fungus contributes its enzymatic apparatus to degrade cellulose. As in the case of so many other natural symbiotic and parasitic associations, the basis is an integration of complementary metabolic capabilities and deficiencies.
In vivo Conversion of3H-L-Tryptophan into3H-Serotonin in Brain Areas of Adrenalectomized Rats
Authors: Azmitia E. C. , Algeri S. , Costa E.
Published: October 2006

Rats were adrenalectomized 10 days before we estimated in vivo the conversion index of3H-tryptophan into radioactive serotonin in brainstem and telediencephalon. We found that the conversion index in the brainstem of adrenalectomized rats is smaller than in the same area of sham-operated rats. Conversely, the conversion index in the telediencephalon was similar in the two groups of rats. The serotonin concentrations were unchanged by adrenalectomy, which suggests that in brainstem the decrease of tryptophan hydroxylase is reflected by the conversion index estimation and not by measurement of serotonin steady-state concentrations.
Differentiation of Immature Mucous Cells into Parietal, Argyrophil, and Chief Cells in Stomach Grafts
Authors: Matsuyama Mutushi , Suzuki Harumi
Published: October 2006

Microscopic and submicroscopic studies on regenerating gastric mucosa neonatally grafted in the subcutaneous tissue of littermate mice have revealed that immature mucous cells are totipotent; ultimately they transform into mature mucous, parietal, argyrophil, and chief cells in the gastric glands.
Allopurinol: Alteration in Pyrimidine Metabolism in Man
Authors: Kelley William N. , Beardmore Thomas D.
Published: October 2006

In addition to its well-established inhibitory effect on uric acid synthesis, allopurinol appears to alter substantially pyrimidine metabolism, as evidenced by a striking increase in the urinary excretion of orotidine and orotic acid. Allopurinol ribonucleotide and xanthosine 5′-monophosphate are potent inhibitors of human erythrocyte orotidylic decarboxylase and provide a possible mechanism for this effect.
Molecular Structure of Charybdotoxin, a Pore-Directed Inhibitor of Potassium Ion Channels
Authors: Massefski Walter , Redfield Alfred G. , Hare Dennis R. , Miller Christopher
Published: October 2006

The three-dimensional structure of charybdotoxin, a high-affinity peptide blocker of several potassium ion channels, was determined by two-dimensional nuclear magnetic resonance (2-D NMR) spectroscopy. Unambiguous NMR assignments of backbone and side chain hydrogens were made for all 37 amino acids. The structure was determined by distance geometry and refined by nuclear Overhauser and exchange spectroscopy back calculation. The peptide is built on a foundation of three antiparallel β strands to which other parts of the sequence are attached by three disulfide bridges. The overall shape is roughly ellipsoidal, with axes of approximately 2.5 and 1.5 nanometers. Nine of the ten charged groups are located on one side of the ellipsoid, with seven of the eight positive residues lying in a stripe 2.5 nanometers in length. The other side displays three hydrophobic residues projecting prominently into aqueous solution. The structure rationalizes several mechanistic features of charybdotoxin block of the high-conductance Ca
2+
-activated K
+
channel.
Mueller-Lyer Illusion: Effect of Age, Lightness Contrast, and Hue
Authors: Pollack Robert H.
Published: October 2006

Mueller-Lyer figures produced by lightness contrast (white on black) and by hue contrast in the absence of lightness contrast (red, yellow, green, or blue on gray) were presented to subjects aged nine to adult. Contrary to Piagetian expectations, the illusion magnitudes resulting from the colored figures did not decline with age.
The Cultural Basis for Our Environmental Crisis
Authors: Moncrief Lewis W.
Published: October 2006

The forces of democracy, technology, urbanization, increasing individual wealth, and an aggressive attitude toward nature seem to be directly related to the environmental crisis now being confronted in the Western world. The Judeo-Christian tradition has probably influenced the character of each of these forces. However, to isolate religious tradition as a cultural component and to contend that it is the "historical root of our ecological crisis" is a bold affirmation for which there is little historical or scientific support.
Carbon Dioxide Clathrate in the Martian Ice Cap
Authors: Miller Stanley L. , Smythe William D.
Published: October 2006

Measurements of the dissociation pressure of carbon dioxide hydrate show that this hydrate (CO
2
⋅ 6H
2
O) is stable relative to solid CO
2
and water ice at temperatures above about 121°K. Since this hydrate forms from finely divided ice and gaseous CO
2
in several hours at 150°K, it is likely to be present in the martian ice cap. The ice cap can consist of water ice, water ice + CO
2
hydrate, or CO
2
hydrate + solid CO
2
, but not water ice + solid CO
2
.
Synthesis of Amino Acids by the Heating of Formaldehyde and Ammonia
Authors: Fox Sidney W. , Windsor Charles R.
Published: October 2006

The heating of formaldehyde and ammonia yields a product that, on hydrolysis, is converted into seven amino acids: aspartic acid, glutamic acid, serine, proline, valine, glycine, and alanine. Glycine is the predominant amino acid. Inasmuch as formaldehyde and ammonia have been identified as compounds in galactic clouds, these experimental results are interpreted in a cosmochemical and geochemical context.
Expression of Murine CD1 on Gastrointestinal Epithelium
Authors: Bleicher Paul A. , Balk Steven P. , Hagen Susan J. , Blumberg Richard S. , Flotte Thomas J. , Terhorst Cox
Published: October 2006

Cluster of differentiation 1 (CD1) in humans is a family of major histocompatibility complex (MHC) class I-like molecules expressed on the surface of immature thymocytes, Langerhans cells, and a subpopulation of B cells. The only function identified for human CD1 is as a ligand recognized by a subpopulation of T lymphocytes. In order to study the distribution and function of these molecules in the mouse, a murine CD1 complementary DNA was expressed in mouse fibroblasts and used to produce monoclonal antibodies. These antibodies revealed prominent expression of murine CD1 only on gastrointestinal tract epithelium and in the cytoplasm of hepatocytes. Low levels of expression were also detected on thymocytes and peripheral lymphocytes. The gastrointestinal distribution of murine CD1 suggests that this molecule may be important in epithelial immunity.
"Polywater": Evidence from Electron Spectroscopy for Chemical Analysis (ESCA) of a Complex Salt Mixture
Authors: Davis R. E. , Rousseau D. L. , Board R. D.
Published: October 2006

The ESCA spectra of "polywater" show that this anomalous, high-density, viscous, nonvolatile material contains high concentrations of sodium, potassium, sulfate, chloride, nitrate, borates, silicates, and carbon-oxygen compounds with trace amounts of other impurities but very little water. On the basis of this evidence, in conjunction with reported spectroscopic and analytical experiments, it is very unlikely that a polymerized form of water has been discovered.
Nerve Trophic Function: In vitro Assay of Effects of Nerve Tissue on Muscle Cholinesterase Activity
Authors: Lentz Thomas L.
Published: October 2006

The effects of tissue explants and nerve homogenates on cholinesterase activity of muscle of the newt
Triturus
in organ culture were measured. Sensory ganglia, ganglia separated from muscle by a Millipore filter, spinal cord, liver, and nerve homogenates produced greater activity of muscle cholinesterase than occurred in untreated muscle cultured for the same period of time. Boiled ganglia, kidney, oviduct, and spleen were ineffective. This procedure serves as a convenient bioassay for a neurotrophic process and indicates that the trophic effect is mediated by a diffusible chemical substance produced by nerves.
Hyperoxaluria in L-Glyceric Aciduria: Possible Pathogenic Mechanism
Authors: Williams Hibbard E. , Smith Lloyd H.
Published: October 2006

The effect of hydroxypyruvate on synthesis of oxalate and glycolate from glyoxylate was studied in in vitro preparations from normal human erythrocytes and leukocytes, rat liver, and with purified lactate dehydrogenase from beef heart. In the presence of reduced nicotinamide adenine dinucleotide, hydroxypyruvate stimulated the oxidation of glyoxylate to oxalate and decreased the reduction of glyoxylate to glycolate. These findings may explain the hyperoxaluria seen in L-glyceric aciduria (type II primary hyperoxaluria).
Artibeus jamaicensis
: Delayed Embryonic Development in a Neotropical Bat
Authors: Fleming Theodore H.
Published: October 2006

In Panama the phyllostomid bat
Artibeus jamaicensis
is seasonally polyestrous, and young are born in March or April and July or August. Blastocysts conceived after the second birth implant in the uterus but are dormant from September to mid-November, when normal development again resumes.
Structure of Water in Microemulsions: Electrical, Birefringence, and Nuclear Magnetic Resonance Studies
Authors: Shah Dinesh O. , Hamlin Roy M.
Published: October 2006

Microemulsions, which are optically transparent oil-water dispersions, were produced by mixing hexadecane, hexanol, potassium oleate, and water. As the amount of water is increased, the microemulsion exhibits a clear to turbid to clear transition. In contrast to the clear regions, the turbid region possesses birefringence. The development of birefringence is also accompanied by a sharp decrease in the electrical resistance. The high-resolution (220 megacycle) nuclear magnetic resonance data suggest that water exists in two distinct molecular environments in the birefringent region; the first environment is characterized by relatively less mobile water molecules than oil molecules, whereas in the second environment oil molecules are less mobile than water molecules. The electrical, birefringence, and nuclear magnetic resonance data are in agreement with the proposed mechanism of change in the structure of water from water spheres to water cylinders to water lamellae. The chemical shift of water protons suggests that the molecular environment of water in spheres is different from that of water in cylinders or that of water in lamellae.
X-ray Structure of the Cygnus Loop
Authors: Gorenstein P. , Harris B. , Gursky H. , Giacconi R. , Novick R. , Bout P. Vanden
Published: October 2006

X-ray emission from the Cygnus Loop was observed in the energy region around 0.2 to 1 kiloelectronvolt with a collector that focused x-rays along one dimension while scanning across the nebula. The total integrated intensity is 1.3 × 10
-8
erg per square centimeter per second. The one-dimensional x-ray structure has the same angular size—about 3 degrees—as the outermost boundaries of the optical filaments. There is no increase in x-ray emission at the center of the nebula nor at the strong feature that is seen in certain radio maps. The x-ray spectrum is consistent with thermal radiation from a hot plasma at a temperature of about 4 × 10
6
°K with evidence for a line at 19 angstroms corresponding to the 2
p
→1
s
transition of O VIII.
Maintenance of Resting Potential in Anoxic Guinea Pig Ventricular Muscle: Electrogenic Sodium Pumping
Authors: McDonald T. F. , MacLeod Don P.
Published: October 2006

Anoxic ventricular muscle maintained a normal resting potential despite a large loss of potassium. The resting potential was separated into two components: one that depended on the potassium distribution, and one that depended on the activity of an electrogenic sodium pump.
Intersexes and Sex Determination in Chickens
Authors: Abdel-Hameed F. , Shoffner R. N.
Published: October 2006

Chickens sexed as females in commercial flocks show a low frequency of intersex individuals. Gross anatomical examination of the intersexes revealed malformed gonads. Histological examination proved that these gonads were not ovotestes but were composed of testicular tissues. Karyotype analysis of 15 intersex individuals showed 13 of them to be 3A-ZZW triploids (normal females are 2A-ZW) while the other 2 were mosaic for male and female karyotypes. Red blood cell volume accurately reflects the ploidy level and is suggested for use in screening for polyploids. Intersex triploids may develop parthenogenetically or from fertilization between reduced and unreduced gametes.
Reverse Transcriptase Encoded by a Human Transposable Element
Authors: Mathias Stephen L. , Scott Alan F. , Kazazian Haig H. , Boeke Jef D. , Gabriel Abram
Published: October 2006

L1 elements are highly repeated mammalian DNA sequences whose structure suggests dispersal by retrotransposition. A consensus L1 element encodes a protein with sequence similarity to known reverse transcriptases. The second open reading frame from the human L1 element L1.2A was expressed as a fusion protein targeted to Ty1 virus-like particles in
Saccharomyces cerevisiae
and shown to have reverse transcriptase activity. This activity was eliminated by a missense mutation in the highly conserved amino acid motif Y/F-X-D-D. Thus, L1 represents a potential source of the reverse transcriptase activity necessary for dispersion of the many classes of mammalian retroelements.
Quasars Revisited: Rapid Time Variations Observed Via Very-Long-Baseline Interferometry
Authors: Whitney Alan R. , Shapiro Irwin I. , Rogers Alan E. E. , Robertson Douglas S. , Knight Curtis A. , Clark Thomas A. , Goldstein Richard M. , Marandino Gerard E. , Vandenberg Nancy R.
Published: October 2006

Recent Goldstone-Haystack radio interferometric observations of the quasars 3C 279 and 3C 273 reveal rapid variations in their fine structure. Most notably, the data for 3C 279, interpreted in terms of a symmetric double-source model and the accepted red-shift distance, indicate differential proper motion corresponding to an apparent speed about ten times that of light. A number of possible mechanisms that might give rise to such an apparent speed are considered; although several may be plausible, no definitive choice can be made on the basis of present evidence. More interferometric observations of quasars are clearly needed to clarify their structure and internal kinematics.
Marihuana: Identification of Cannabinoids by Centrifugal Chromatography
Authors: Petcoff Darrell G. , Strain S. Michael , Brown William R. , Ribi Edgar
Published: October 2006

Components in extracts of marihuana and hashish have been identified by a chromatographic technique in which centrifugal force is used to accelerate the migration of samples through columns of densely packed microparticulate gel. Rapid qualitative analysis and an estimate of the amounts of cannabinoids present was achieved.
Gonadotropin-Releasing Hormone: One Polypeptide Regulates Secretion of Luteinizing and Follicle-Stimulating Hormones
Authors: Schally A. V. , Arimura A. , Kastin A. J. , Matsuo H. , Baba Y. , Redding T. W. , Nair R. M. G. , Debeljuk L. , White W. F.
Published: October 2006

A polypeptide isolated from porcine hypothalami stimulates the release of both luteinizing hormone and follicle-stimulating hormone from the pituitaries of several species. This polypeptide has been structurally identified as (pyro)Glu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly-NH
2
and synthesized. The natural and synthetic materials share biological properties. It appears that this peptide represents the hypothalamic hormone regulating the secretion of both luteinizing hormone and follicle-stimulating hormone.
Nonencapsidated Infectious DNA of Adeno-Satellite Virus in Cells Coinfected with Herpesvirus
Authors: Boucher D. Wark , Melnick Joseph L. , Mayor Heather D.
Published: October 2006

Adeno-associated satellite viruses produce antigen detectable by immunofluorescence but not infectious virus in tissue culture cells coinfected with herpes simplex virus. Analysis of DNA extracts from these infected cells shows that large amounts of infectious satellite virus DNA are produced but not encapsidated in the system. This result indicates that satellite virus may be defective at the maturation step.
Chondroitin Sulfate as a Regulator of Neuronal Patterning in the Retina
Authors: Brittis Perry A. , Canning David R. , Silver Jerry
Published: October 2006

Highly sulfated proteoglycans are correlated with axon boundaries in the developing central nervous system which suggests that these molecules affect neural pattern formation. In the developing mammalian retina, gradual regression of chondroitin sulfate may help control the onset of ganglion cell differentiation and initial direction of their axons. Changes induced by the removal of chondroitin sulfate from intact retinas in culture confirm the function of chondroitin sulfate in retinal histogenesis.
Buffer Combinations for Mammalian Cell Culture
Authors: Eagle Harry
Published: October 2006

The growth and metabolism of cultured mammalian cells are markedly affected by the
p
H variation in ordinary bicarbonate-buffered media (
p
H 8.0 to 6.9). Those
p
H swings can be reduced and the
p
H of the culture can be stabilized as desired in the range
p
H 6.4 to 8.3 by appropriate combinations of two or three organic buffers, each at 10 to 15 millimolar, in conjunction with phosphate and bicarbonate. The initial alkalinization in sparse cultures is then minimized, and the metabolic acidification in 24 hours is usually less than 0.4
p
H unit except in heavy cultures.
The Cholinergic Synapse and the Site of Memory
Authors: Deutsch J. Anthony
Published: October 2006

A simple hypothesis can explain the results obtained to date if we disregard those results when we wait 30 minutes after original learning to inject. The hypothesis is that, as a result of learning, the postsynaptic endings at a specific set of synapses become more sensitive to transmitter. This sensitivity increases with time after initial learning and then declines. The rate at which such sensitivity increases depends on the amount of initial learning. If the curve of transmission plotted against time is displaced upward with anticholinesterases then the very low portions will show facilitation, and the high portions will cause block (Fig. 8). The middle portions will appear unaffected (unless special experimental tests are made). If the curve of transmission is displaced down with anticholinergics, then the middle portion will appear unaffected and only the very early or late components will show block.

The results are evidence that synaptic conductance is altered as a result of learning. So far it seems (i) that cholinergic synapses are modified as a result of learning and that it probably is the postsynaptic membrane that becomes increasingly more sensitive to acetylcholine with time after learning, up to a certain point. (ii) After this point, sensitivity declines, leading to the phenomenon of forgetting. (iii) There is also good evidence that there is an initial phase of declining sensitivity to cholinesterase or increasing sensitivity to anticholinergics. This could reflect the existence of a parallel set of synapses with fast decay that serve as a shortterm store. (iv) Increasing the amount of learning leads to an increase in conductance in each of a set of synapses without an increase in their number. (v) Both original learning and extinction are subserved by cholinergic synapses.
Precambrian Columnar Stromatolite Diversity: Reflection of Metazoan Appearance
Authors: Awramik Stanley M.
Published: October 2006

Columnar stromatolites (organosedimentary structures built by blue-green algae) show a marked decrease in diversity in the Late Precambrian; this decrease in diversity occurs at approximately the same time as the appearance of metazoans, 600 to 700 million years ago.
DDT in the Biosphere: Where Does It Go?
Authors: Woodwell George M. , Craig Paul P. , Johnson Horton A.
Published: October 2006

The worldwide pattern of movement of DDT residues appears to be from the land through the atmosphere into the oceans and into the oceanic abyss. Calculations based on the fragmentary data available on rates of movement and sizes of various pools of DDT residues lead to the conclusion that concentrations in the atmosphere and in the mixed layer of the oceans lag by only a few years behind the amounts of DDT used annually throughout the world. A model suggests that maximum concentrations of DDT residues occurred in air in 1966 and will occur in the mixed layer of the oceans in 1971. The biota probably contains in total less than 1/30 of 1 year's production of DDT during the mid-1960's, a very small amount in proportion to the total potentially available. The reason for the biota's failure to absorb larger quantities and to be affected much more severely is unclear. The analysis suggests that mere good fortune has protected man and the rest of the biota from much higher concentrations, thus emphasizing the need to determine the details of the movement of DDT residues and other toxins through the biosphere and to move swiftly to bring world use of such toxins under rational control based on firm knowledge of local and worldwide cycles and hazards.
Analgesia from Electrical Stimulation in the Brainstem of the Rat
Authors: Mayer David J. , Wolfle Thomas L. , Akil Huda , Carder Brooks , Liebeskind John C.
Published: October 2006

Stimulation at several mesencephalic and diencephalic sites abolished responsiveness to intense pain in rats while leaving responsiveness to other sensory modes relatively unaffected. The peripheral field of analgesia was usually restricted to one-half or to one quadrant of the body, and painful stimuli applied outside this field elicited a normal reaction. Analgesia outlasted stimulation by up to 5 minutes. Most electrode placements that produced analgesia also supported self-stimulation. One placement supported self-stimulation only in the presence of pain.
Mariner 9 Ultraviolet Spectrometer Experiment: Initial Results
Authors: Barth Charles A. , Hord Charles W. , Stewart A. Ian , Lane Arthur L.
Published: October 2006

The ultraviolet airglow spectrum of Mars has been measured from an orbiting spacecraft during a 30-day period in November-December 1971. The emission rates of the carbon monoxide Cameron and fourth positive bands, the atomic oxygen 1304-angstrom line and the atomic hydrogen 1216-angstrom line have been measured as a function of altitude. Significant variations in the scale height of the CO Cameron band airglow have been observed during a period of variable solar activity; however, the atomic oxygen and hydrogen airglow lines are present during all the observations. Measurements of the reflectance of the lower atmosphere of Mars show the spectral characteristics of particle scattering and a magnitude that is about 50 percent of that measured during the Mariner 6 and 7 experiments in 1969. The variation of reflectance across the planet may be represented by a model in which the dominant scatterer is dust that absorbs in the ultraviolet and has an optical depth greater than 1. The atmosphere above the polar region is clearer than over the rest of the planet.
Crayfish Muscle Receptor Organ: Role in Regulation of Postural Flexion
Authors: Page Charles H. , Sokolove Phillip G.
Published: October 2006

Recordings were made from postural-control motor nerves with antagonistic functions in the crayfish abdomen through flexible suction electrodes. During unrestrained flexion of the abdomen, output from the tonic stretch receptor neuron of RM
1
(SR
1
) is sufficient to drive an extensor motor unit in the same segment. However, this intrasegmental "resistance" reflex is normally blocked by an intersegmental reflex in which output from SR
1
's in caudal segments inhibits SR
1
discharge in more anterior segments.
Lead-212 in the Urban Boundary Layer of New York City
Authors: Assaf Gad , Biscaye Pierre E.
Published: October 2006

The radioactive emanation product lead-212 is useful in estimating rates of air exchange within the urban boundary layer. The concentration of lead-212 is negligible in air of oceanic origin as well as in air above continental areas under snow cover. On several days when conditions were such that one of these types of air mass approached New York City, measurements were made which show that the source strength of lead-212 within the city is relatively constant. On two such days vertical profiles of the concentration of lead-212 were measured from the Empire State Building, which served as a sampling tower. From the data of these profiles and a two-layer model of the urban boundary layer, we estimate the vertical eddy diffusivity to be of the order of tens of square meters per second and the residence time of air within the street layer to be of the order of 5 minutes. These results are consistent with the observed distribution of stable lead and with an independent estimate of the eddy viscosity from a wind profile. Under moderate wind conditions and with a mixing depth of hundreds of meters, virtually all the horizontal transport of lead-212 and other tracers with street-level sources takes place in the advective layer.
3C279: Evidence for a Non-Superrelativistic Model
Authors: Dent William A.
Published: October 2006

Measurements of the variation of the total flux density of the quasistellar radio source 3C279 provide evidence for an alternate model to explain the recently reported apparent source expansion rate of ten times the speed of light.
Maintenance of Normoglycemia in Diabetic Mice by Subcutaneous Xenografts of Encapsulated Islets
Authors: Lacy Paul E. , Hegre Orion D. , Gerasimidi-Vazeou Andriani , Gentile Frank T. , Dionne Keith E.
Published: October 2006

The goal of islet transplantation in human diabetes is to maintain the islet grafts in the recipients without the use of immunosuppression. One approach is to encapsulate the donor islets in permselective membranes. Hollow fibers fabricated from an acrylic copolymer were used to encapsulate small numbers of rat islets that were immobilized in an alginate hydrogel for transplantation in diabetic mice. The fibers were biocompatible, prevented rejection, and maintained normoglycemia when transplanted intraperitoneally; hyperglycemia returned when the fibers were removed at 60 days. Normoglycemia was also maintained by subcutaneous implants that had an appropriately constructed outer surface on the fibers.
Water-Soluble Derivatives of Δ1-Tetrahydrocannabinol
Authors: Zitko B. A. , Howes J. F. , Razdan R. K. , Dalzell B. C. , Dalzell H. C. , Sheehan John C. , Pars H. G. , Dewey W. L. , Harris L. S.
Published: October 2006

Δ1-Tetrahydrocannabinol, which is resinous and insoluble in water and therefore difficult to study pharmacologically, can be converted to a water-soluble derivative without loss of its biological activity. This has been achieved by preparing esters bearing a nitrogen moiety with the use of carbodiimide as the condensing agent. The availability of such water-soluble derivatives will allow the evaluation of Δ1-tetrahydrocannabinol in self-administration studies in monkeys for its addiction liability potential in man. This technique of water solubilization is also applicable to other compounds of chemical and biological significance.
Human Insulin: Facile Synthesis by Modification of Porcine Insulin
Authors: Ruttenberg Michael A.
Published: October 2006

Human insulin differs from porcine insulin by a single amino acid— the carboxyl terminal residue of the B chain. By means of chemical and enzymatic treatment, it is possible to remove quantitatively and selectively the carboxyl terminal octapeptide from porcine insulin B chain. This fragment can be replaced by an analogous synthetic human octapeptide to give a protein which is identical to human insulin by a number of criteria. By this method, human insulin can be prepared on a large scale simply and inexpensively from porcine insulin. The method is also useful for preparing specifically labeled radioactive human insulin, as well as insulins with modified amino acid sequences, for research purposes.
Broad-Spectrum Antiviral Activity of Virazole: 1-β-D-Ribofuranosyl-1,2,4-triazole-3-carboxamide
Authors: Sidwell Robert W. , Huffman John H. , Khare, Lois G. P. , Allen B. , Witkowski, Roland J. T. , Robins K.
Published: October 2006

Virazole is a synthetic nucleoside active in tissue culture against at least 16 DNA and RNA viruses. Applied topically, it inhibits herpetic keratitis in rabbits and tail lesions induced by herpes, vaccinia, and vesicular stomatitis viruses in mice. Injected intraperitoneally into mice, it inhibits splenomegaly and hepatomegaly induced by Friend leukemia virus and respiratory infections caused by influenza A
0
, A
2
, and B viruses and parainfluenza 1 virus. Oral or aerosol treatment of parainfluenza virus infections is also effective.
Lead Poisoning: Rapid Formation of Intranuclear Inclusions
Authors: Choie David D. , Richter G. W.
Published: October 2006

A single dose of lead (0.05 milligram per gram of body weight) induced characteristic intranuclear inclusions in the epithelium of proximal tubules in rat kidney within 1 to 6 days. The development of the intranuclear inclusions is thus an acute manifestation of lead poisoning, not a delayed one, as has been thought hitherto. Cytoplasmic structures resembling the intranuclear inclusions and situated in the vicinity of endoplasmic reticulum were regularly found in cells bearing the pathognomonic intranuclear inclusions. The latter and the cytoplasmic structures may be derived from a common precursor, perhaps a soluble protein-lead complex.
Taste Stimuli: Time Course of Peripheral Nerve Response and Theoretical Models
Authors: Faull John R. , Halpern Bruce P.
Published: October 2006

The responses of a taste nerve in rats to sodium chloride were integrated over successive 10-millisecond intervals and averaged. The time course of the mean responses consisted of a 30-millisecond latency, a rapid rise to a maximum, and a slower decline to a sustained level. The chemoreceptor theories of Beidler and Paton failed to predict the relation between phasic response and time or concentration.
Water-Soluble Insulin Receptors from Human Lymphocytes
Authors: Gavin James R. , Buell Donald N. , Roth Jesse
Published: October 2006

Specific insulin receptors from human lymphocytes in culture have been prepared in aqueous solution without use of detergents or related compounds. Receptors prepared in this fashion exhibit characteristics identical to those reported in intact cells.
Herpesvirus hominis
: Isolation from Human Trigeminal Ganglion
Authors: Bastian F. O. , Rabson A. S. , Yee C. L. , Tralka T. S.
Published: October 2006

Herpesvirus hominis
was isolated from the trigeminal ganglion obtained at autopsy from 1 of 22 patients with no clinical evidence of active herpetic disease, and from one patient with malignant lymphoma who died with herpes zoster on the abdomen, pulmonary cytomegalic inclusion disease, and possible oral herpes simplex. Virus was isolated by cocultivation of explants of ganglion with monolayers of Vero green monkey kidney cells and required 3 weeks of culture before viral cytopathic effects were evident. These observations support the concept that latent infection of sensory ganglia may be the source of virus in recurrent herpetic disease in man.