bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Basis for the Inhibition of Protein Biosynthesis: Mode of Action of Tubulosine
Authors: Grollman Arthur P.
Published: October 2006

A structural model for the inhibition of protein biosynthesis was previously formulated on the basis of a topochemical analogy between the ipecac alkaloids and the glutarimide antibiotics. The structure of tubulosine satisfies the requirements of this model. The prediction that such a compound would exhibit amebicidal activity and act by selectively inhibiting the transfer reaction in protein biosynthesis is confirmed.
Frequency Sensitivity of Single Auditory Neurons in the Gecko
Coleonyx variegatus
Authors: Suga Nobuo , Campbell Howard W.
Published: October 2006

Although acoustic communication is not pronounced in reptiles, analysis of single auditory neurons in the medulla oblongata shows that the cochlea is a frequency analyser. Auditory neurons of the lizard
Coleonyx variegatus
respond to acoustic stimuli over a range of less than 0.1 to 17 kilohertz and are maximally responsive between 0.8 and 2.0 kilohertz. The frequencies to which they are most sensitive differ from neuron to neuron, ranging from 0.11 to 4 kilohertz. Some neurons have an inhibitory area which greatly overlaps the response area, so that inhibitory areas do not seem to sharply tune the response area at this level of the auditory tract. The inhibitory area is responsible for producing in some neurons a phasic response and nonmonotonic relation between sound intensity and number of impulses. The response pattern shows a tendency to change from tonic to phasic in more advanced auditory centers. This may serve to code rapid changes in the acoustic stimuli.
Bistatic-Radar Detection of Lunar Scattering Centers with Lunar Orbiter I
Authors: Tyler G. L. , Eshleman V. R. , Fjeldbo G. , Howard H. T. , Peterson A. M.
Published: October 2006

Continuous-wave signals transmitted from Lunar Orbiter I have been received on Earth after they have been reflected from the surface of the moon. The frequency spectrum of the reflected signals is used to locate discrete, heterogeneous, scattering centers on the lunar surface. The scattering centers are probably distinguished from the surrounding terrain by a higher surface reflectivity. Continuous-wave bistatic radar could provide an important new method for the study and mapping of planetary surfaces.
High-Resolution Nuclear Magnetic Resonance Spectroscopy
Authors: Ferguson R. C. , Phillips W. D.
Published: October 2006

The rapid development of NMR spectroscopy has been characterized by a succession of discrete, significant advances in instrumentation, as well as by less dramatic but cumulatively important improvements in instrument performance, experimental techniques, spectral analysis, and theory. Most significant are the advances in magnet technology, which within 13 years increased the available field strengths from 7.04 to 51.7 kilogauss (with corresponding increase in the PMR frequency from 30 to 220 megahertz). Great improvements in spectrometer stability and in the coupling of spectrometers with on-line computers have so improved sensitivity that some nuclei possessing less favorable NMR characteristics can now be studied.
Puromycin Effect on Memory May Be Due to Occult Seizures
Authors: Cohen Harry D. , Barondes Samuel H.
Published: October 2006

Intracerebral injections of puromycin, which have been shown to impair memory 3 hours after training, increase the susceptibility of mice to seizures after administration of normally subconvulsive doses of pentylenetetrazol. Cycloheximide, which antagonizes the puromycin-induced amnesia 3 hours after training, also antagonizes the puromycin effect on susceptibility to seizure. The anticonvulsant diphenylhydantoin antagonizes the puromycin effect on memory. The puromycin effect on memory may be due to occult seizures.
Virus-Induced Hydrocephalus: Development of Aqueductal Stenosis in Hamsters after Mumps Infection
Authors: Johnson Richard T. , Johnson Kenneth P. , Edmonds C. Jill
Published: October 2006

Hydrocephalus developed as a sequela of mumps virus infections of suckling hamsters. The initial infection after intracerebral inoculation was limited largely to ependymal cells lining the ventricles. This infection was clinically inapparent but later resulted in a noninflammatory stenosis or occlusion of the aqueduct of Sylvius.
Meander Wavelength of Alluvial Rivers
Authors: Schumm S. A.
Published: October 2006

Data on river channel and sediment characteristics were collected at 36 cross sections of stable alluvial river channels in Australia and western United States. These data demonstrate that the meander wavelength of a river is dependent not only on water discharge, but also on the type of sediment load moved through the channel. The meander wavelength of rivers that are transporting a high proportion of their total sediment load as both sand and gravel will be greater than the meander wavelengths of channels of similar discharge which are transporting mainly fine sediment loads.
Isotopic Analysis of Rare Gases with a Laser Microprobe
Authors: Megrue G. H.
Published: October 2006

A ruby-pulsed laser and high-sensitivity mass spectrometer are used to analyze isotopic abundances of rare gases from microgram samples of polished sections. The feasibility of the technique is demonstrated by the analysis of primordial helium and neon from the Kapoeta and Fayetteville meteorites.
Protein-Synthesizing Activity of the Anucleate Polar Lobe of the Mud Snail
Ilyanassa obsoleta
Authors: Clement Anthony C. , Tyler Albert
Published: October 2006

Polar lobes of eggs of the mud snail
Ilyanassa obsoleta
, detached at the "trefoil" stage of the first cleavage, are capable of incorporating labeled amino acid into protein. The rate of incorporation per unit volume is about half that of the whole egg. The ability to incorporate at a similar rate persists for at least 24 hours after isolation. The sum of the incorporation of isolated lobes and lobeless fragments approximates that of the whole egg. The results extend to this material (the anucleate polar lobe) evidence for long-lived messenger RNA. They suggest also that the demonstrated morphogenetic influence of the lobe, which is exerted primarily during cleavage, may be correlated with its ability to synthesize protein.
Enzyme Reaction Rates at Limited Water Activities
Authors: Skujins J. J. , McLaren A. D.
Published: October 2006

A well-mixed powder consisting of dry urea and urease exposed to air containing discrete amounts of water vapor showed a release of carbon-14 dioxide above 60-percent relative humidity. The relative activity of urease followed the water-vapor adsorption isotherm of urease. The minimum amount of water required for the reaction observed was 1.3 moles per mole of side-chain polar groups of the urease protein.
A Requirement for Two Cell Types for Antibody Formation in vitro
Authors: Mosier Donald E.
Published: October 2006

A suspension of mouse spleen cells can be separated into two populations on the basis of their ability or inability to adhere to plastic dishes. It was found that both adherent and nonadherent cells were necessary for the induction of antibody formation to sheep red blood cells in vitro. Exposure of adherent cells to antigen for brief periods of time was sufficient to initiate a maximal in vitro response.
Red Cells Coated with Immunoglobulin G: Binding and Sphering by Mononuclear Cells in Man
Authors: LoBuglio Albert F. , Cotran Ramzi S. , Jandl James H.
Published: October 2006

Human monocytes, macrophages, and certain lymphocytes bind firmly to red cells coated with immunoglobulin G, whether or not it is acting as antibody. Monocyte binding is specific for cells coated with immunoglobulin G and is inhibited specifically by this immunoglobulin or its Fc-fragment in solution. Although not involving serum complement and not usually a prelude to erythrophagocytosis, this binding causes rapid morphological injury to red cells, as manifested by their sphering, increased osmotic fragility, deformation, and fragmentation. It is inferred that mononuclear cells have specific surface receptors for immunoglobulin G and that these provide a critical phase of the mechanism in vivo, whereby red cells or other particles coated with antibody are apprehended and destroyed.
Fast Perceptual Learning in Visual Hyperacuity
Authors: Poggio Tomaso , Fahle Manfred , Edelman Shimon
Published: October 2006

In many different spatial discrimination tasks, such as in determining the sign of the offset in a vernier stimulus, the human visual system exhibits hyperacuity by evaluating spatial relations with the precision of a fraction of a photoreceptor's diameter. It is proposed that this impressive performance depends in part on a fast learning process that uses relatively few examples and that occurs at an early processing stage in the visual pathway. This hypothesis is given support by the demonstration that it is possible to synthesize, from a small number of examples of a given task, a simple network that attains the required performance level. Psychophysical experiments agree with some of the key predictions of the model. In particular, fast stimulus-specific learning is found to take place in the human visual system, and this learning does not transfer between two slightly different hyperacuity tasks.
Venom of the Scorpion
Vejovis spinigerus
Authors: Russell Findlay E. , Alender Charles B. , Buess Fred W.
Published: October 2006

The chemical composition of lyophilized venom from
Vejovis spinigerus
is reported. At least 13 distinct bands were obtained on disc electrophoresis; on Sephadex G-50, four major peaks were found. The lethal activity was associated with the second peak. The intravenous lethal dose, median (lethal for 50 percent of inoculated group), of the crude venom was 4.87 milligrams per kilogram of body weight. Neither the crude venom nor its fractions had a deleterious effect on neuromuscular transmission, reflex discharge, or antidromic inhibition. Crude venom evoked simultaneous changes in systemic arterial, venous, and cisternal pressures.
Ammonium Ion Concentration in the Primitive Ocean
Authors: Bada Jeffrey L. , Miller Stanley L.
Published: October 2006

If ion exchange on clay minerals regulated the cations in the primitive ocean as it does in the present ocean, the
p
H would have been 8 and the K
+
concentration 0.01
M
. Since NH
4
+
and K
+
are similar in their clay-mineral equilibria, the maximum NH
4
+
concentration in the primitive ocean would also have been 0.01
M
. An estimate of the minimum NH
4
+
concentration is 1 × 10
-3
M
, based on the reversible deamination of aspartic acid and the assumption that aspartic acid is necessary for the origin of life. The rate of this nonenzymic deamination is rapid on the geological time scale.
Diatremes with Kimberlitic Affinities in North-Central Montana
Authors: Hearn B. Carter
Published: October 2006

Diatremes in the Missouri River Breaks demonstrate systematic subsidence-ring structure, contain inclusions derived from far above and far below, and have been produced by gas-rich eruptions of alkalic ultramafic magmas. Similar magmas have produced diatremes in many localities in the world and are known to be closely associated with and probably parental to kimberlites.
Venera 4 Probes Atmosphere of Venus
Authors: Reese David E. , Swan Paul R.
Published: October 2006

The atmospheric data and information on trajectory received from Venera 4 together provide consistent and firm evidence of its success in reaching the surface of Venus.
Amino Acid Flux in an Estuary
Authors: Hobbie John E. , Crawford Claude C. , Webb Kenneth L.
Published: October 2006

Dissolved organic matter in York River estuary included 38 micrograms of free amino acids per liter. The highest concentrations were of glycine, serine, and ornithine. Of the 14 amino acids studied for uptake by planktonic bacteria, glycine, methionine, and serine had the greatest flux rates. The total amino acid flux represented from 1 to 10 percent of the daily photosynthetic carbon fixation.
Gravitational Inconsistency in the Lunar Theory: Confirmation by Radio Tracking
Authors: Cary C. N. , Sjogren W. L.
Published: October 2006

When range and Doppler observations of space probes near or on Moon are reduced by use of a lunar ephemeris calculated from the Brown lunar theory, residuals as large as 440 meters in position and 1.5 millimeters per second in velocity are observed. When the calculations are repeated with use of LE 5, the integrated lunar ephemeris described, the residuals are greatly reduced.
Dihydromatricaria Acid: Acetylenic Acid Secreted by Soldier Beetle
Authors: Meinwald J. , Meinwald Y. C. , Chalmers A. M. , Eisner T.
Published: October 2006

The aposematic cantharid beetle
Chauliognathus lecontei
produces a defensive secretion, from glands in its thorax and abdomen, containing 8-
cis
-dihydromatricaria acid. Similar acetylenic compounds are known only from certain fungi and flowering plants.
Nobelium: Tracer Chemistry of the Divalent and Trivalent Ions
Authors: Maly Jaromir , Sikkeland Torbjorn , Silva Robert , Ghiorso Albert
Published: October 2006

In the absence of oxidizing or reducing agents the chromatographic and coprecipitation behavior of element 102 is similar to that of the alkaline earth elements. After oxidation with ceric ions, the behavior is that expected of a trivalent actinide. Nobelium is the first actinide for which the +2 oxidation state is the most stable species in aqueous solution.
Life's Irreducible Structure
Authors: Polanyi Michael
Published: October 2006

Mechanisms, whether man-made or morphological, are boundary conditions harnessing the laws of inanimate nature, being themselves irreducible to those laws. The pattern of organic bases in DNA which functions as a genetic code is a boundary condition irreducible to physics and chemistry. Further controlling principles of life may be represented as a hierarchy of boundary conditions extending, in the case of man, to consciousness and responsibility.
Crystal Structure of a Complex of Acridine, Cytosine, and Water (1: 1 : 1)
Authors: Shefter Eli
Published: October 2006

X-ray structural analysis of a crystalline complex between acridine C
13
H
9
N, cytosine C
4
H
5
N
3
O, and water (1:1:1) has been completed. The cytosine and water molecules form a sheet-like structure through a series of hydrogen bonds. The acridine molecules are bound to this layer through a hydrogen bridge from the water to the ring nitrogen. The acridine molecules stack in a parallel fashion normal to the cytosine-water sheets, with an average interplanar spacing of 3.5 angstroms.
Aminoacyl Esterase Activity of the
Tetrahymena
Ribozyme
Authors: Piccirilli Joseph A. , McConnell Timothy S. , Zaug Arthur J. , Noller Harry F. , Cech Thomas R.
Published: October 2006

Several classes of ribozymes (catalytic RNA's) catalyze reactions at phosphorus centers, but apparently no reaction at a carbon center has been demonstrated. The active site of the
Tetrahymena
ribozyme was engineered to bind an oligonucleotide derived from the 3′ end of
N
-formyl-methionyl-tRNA
fMet
. This ribozyme catalyzes the hydrolysis of the aminoacyl ester bond to a modest extent, 5 to 15 times greater than the uncatalyzed rate. Catalysis involves binding of the oligonucleotide to the internal guide sequence of the ribozyme and requires Mg
2+
and sequence elements of the catalytic core. The ability of RNA to catalyze reactions with aminoacyl esters expands the catalytic versatility of RNA and suggests that the first aminoacyl tRNA synthetase could have been an RNA molecule.
5-Diazo-4-Oxo-L-Norvaline: Reactive Asparagine Analog with Biological Specificity
Authors: Handschumacher R. E. , Bates C. J. , Chang P. K. , Andrews A. T. , Fischer G. A.
Published: October 2006

The L-asparagine analog, 5-diazo-4-oxo-L-norvaline, specifically inactivates L-asparaginase and inhibits the growth of L-asparagine-dependent or L-asparaginase-sensitive tumor cells in culture. With 5-
14
C-labeled compound, a biphasic incorporation into sensitive cells occurs, but the inhibition of cell multiplication is manifest much later than the rapid phase of incorporation of the analog.
Lateralized Suppression of Dichotically Presented Digits after Commissural Section in Man
Authors: Milner Brenda , Taylor L. , Sperry R. W.
Published: October 2006

Right-handed patients with surgical disconnection of the cerebral hemispheres cannot report verbal input to the left ear if different verbal stimuli have been channeled simultaneously to the right ear. With monaural stimulation, they show equal accuracy of report for the two ears. These findings highlight the dominance of the contralateral over the ipsilateral auditory projection system. Suppression of right-ear input is obtained in nonverbal tests. Dissociation between verbal and left-hand stereognostic responses indicate a right-left dichotomy for auditory experience in the disconnected hemispheres.
4-Leucine-Oxytocin: Natriuretic, Diuretic, and Antivasopressin Polypeptide
Authors: Chan W. Y. , Hruby Victor J. , Flouret George , du Vigneaud Vincent
Published: October 2006

During water diuresis in anesthetized rats, 4-leucine-oxytocin increased the urine output and the rates of sodium and chloride excretion. The potassium excretion rate was only slightly increased. During vasopressin-suppressed water diuresis, 4-leucine-oxytocin produced similar effects on urine and electrolyte excretions. In addition, it inhibited the vasopressin-induced free-water reabsorption, and it could reverse reabsorption to free-water clearance.
Mascons: Lunar Mass Concentrations
Authors: Muller P. M. , Sjogren W. L.
Published: October 2006

Lunar Orbiter tracking data have been processed to supply a qualitatively consistent gravimetric map of the lunar nearside. While a simplified model was employed, the results indicate that there are large mass concentrations under the lunar ringed maria. These mass concentrations may have important implications for the various theories regarding lunar history.
Fissure Basalts and Ocean-Floor Spreading on the East Pacific Rise
Authors: Bonatti Enrico
Published: October 2006

A basalt pavement outcrops almost continuously in a band along the crestal region of the East Pacific Rise from about 14°S to 6°S, that is, for more than 800 ikilometers; the outcrop may well extend beyond the above limits along the axis of the rise. The basalt band is generally between 40 and 60 kilometers wide and is replaced laterally by sediment. The lavas are fresh, "oceanic tholeiites" which were emplaced less than I million years ago by fissure eruptions. These findings, can be explained by the hypothesis of ocean-floor spreading; the basalts are the expression of material originating from the mantle and rising through fissures along the axis of the ridge. The absence of an axial rift valley on the East Pacific Rise may be explained by the fact that large volumes of lava are being outpoured along its crest.
Clay Sols versus Clay Gels: Biological Activities Compared
Authors: Low Philip F. , Davey Brian G. , Lee Kwang W. , Baker Dale E.
Published: October 2006

Clay gels were prepared by extrusion of sodium-Wyoming bentonite pastes through a small orifice. Clay sols were prepared from the gels by rapping on the laboratory bench for disturbance. Lettuce seeds germinated faster, microbes generated more heat, and corn seedlings absorbed more
22
Na in the sols than in the gels. These differences in biological activity are attributable to changes in water properties and ion activities that accompany transformation from gel to sol.
Antarctic Ice Sheet: Preliminary Results of First Core Hole to Bedrock
Authors: Gow Anthony J. , Ueda Herbert T. , Garfield Donald E.
Published: October 2006

The Antarctic ice sheet at Byrd Station has been core-drilled to bedrock; the vertical thickness of the ice is 2164 meters. Liquid water—indicative of pressure melting—was encountered at the bed. Heat flow through the base of the ice sheet is estimated at 1.8 microcalories per square centimeter per second. The minimum temperature was -28.8°C at 800 meters; maximum ice density, 0.9206 at 1000 meters. Core studies reveal the existence of a chemically pure, structurally stratified sheet comprising bubbly ice to 900 meters that transforms to bubble-free deformed ice, with substantially vertically orientated c-axis structure, below 1200 meters. Below 1800 meters the deformed ice structure gives way to large annealed crystals. Several thin layers of dirt between 1300 and 1700 meters are tentatively identified as volcanic ash, and horizontally banded debris, including fragments of granite, is present in the basal ice.
Clear-Air Turbulence and Sporadic E Activity
Authors: McKay A. Ronald
Published: October 2006

Pilots' reports of clear-air turbulence correlate inferentially with sporadic E activity observed by backscatter radar. A cursory survey was made of 19 reports of turbulence between 1 and 20 August 1964 over the western United States; all but three correlate with sporadic E patches.
Seawater Hydrogen-Ion Concentration: Vertical Distribution
Authors: Park P. Kilho
Published: October 2006

Two major processes that affect the vertical distribution of hydrogen-ion concentration in the sub-Arctic region of the northeastern Pacific Ocean are the apparent oxygen utilization by marine organisms and, to a lesser extent, carbonate dissolution.
Mass of Pluto
Authors: Duncombe R. L. , Klepczynski W. J. , Seidelmann P. K.
Published: October 2006

Analysis of the observations of Neptune indicates a reciprocal mass of Pluto of 1,812,000 (0.18 Earth masses). If the density is the same as that of Earth, the diameter would be 7200 kilometers. If 6400 kilometers is accepted (from other sources) as the upper limit of the diameter, then Pluto must be at least 1.4 times as dense as Earth.
Evidence that eukaryotes and eocyte prokaryotes are immediate relatives
Authors: Rivera Maria C. , Lake James A.
Published: October 2006

The phylogenetic origin of eukaryotes has been unclear because eukaryotic nuclear genes have diverged substantially from prokaryotic ones. The genes coding for elongation factor EF-1α were compared among various organisms. The EF-1α sequences of eukaryotes contained an 11-amino acid segment that was also found in eocytes (extremely thermophilic, sulfur-metabolizing bacteria) but that was absent in all other bacteria. The related (paralogous) genes encoding elongation factor EF-2 and initiation factor IF-2 also lacked the 11-amino acid insert. These data imply that the eocytes are the closest surviving relatives (sister taxon) of the eukaryotes.
Cloud Condensation Nuclei from a Simulated Forest Fire
Authors: Hobbs Peter V. , Radke L. F.
Published: October 2006

Measurements made downwind of a simulated forest fire showed that the concentration of cloud condensation nuclei active at a supersaturation of 1 percent was increased by a factor of about 2.5. Smaller increases were observed at lower supersaturations.
Hormonal Termination of Larval Diapause in
Dermacentor albipictus
Authors: Wright James E.
Published: October 2006

The molting hormone, α-ecdysone, and an analog Δ
7
-5β-cholestene-2β,3β,14α-triol-6-one when applied externally, terminates diapause in larvae of the winter tick,
Dermacentor albpictus
. This is the first reported hormonal termination of diapause in an arthropod other than an insect.
Polymethacrylic Acid: Effects on Lymphocyte Output of the Thoracic Duct in Rats
Authors: Ormai S. , De Clercq E.
Published: October 2006

The synthetic polyanion, polymethacrylic acid, was applied intravenously to thoracic duct cannulated rats. An increase of the lymphocyte count occurred in the lymph and in the peripheral blood. Polymethacrylic acid mobilized the lymphocytes from the reservoirs.
Immunosuppressive Activity of Concanavalin A
Authors: Markowitz Harold , Person Donald A. , Gitnick Gary L. , Ritts Roy E.
Published: October 2006

Two strains of mice (C-57 B1 and DBA) were given skin allografts from Swiss ICR/HA mice and were treated with varying doses of concanavalin A; the dosage ranged from only two injections of 25 micrograms during the experiment to daily doses of 1000 micrograms intraperitoneally. Immunosuppression was present at all dosages, the most prolonged and consistent effect being observed at 300 micrograms per day. Grafts survived for 14 to 21 days at this dosage compared to 4 to 9 days for controls.
Vitamin A Deficiency: Effect on Mosquito Eye Ultrastructure
Authors: Brammer J. D. , White Richard H.
Published: October 2006

Mosquitoes (
Aedes aegypti
) were reared aseptically for one generation on an artificial diet containing neither vitamin A nor its usual precursor in animals, β-carotene. Function (electrical response to light) in the compound eyes of these animals was severely impaired. Ultrastructure of the photoreceptor cells was abnormal in two respects: multivesicular bodies were absent, and masses of smooth membrane lamellae were present near the nucleus. The organization of the photoreceptor organelle, the rhabdomere, was normal. The eyes of control mosquitoes, to whose diet β-carotene was added, were functionally and structurally normal. Multivesicular bodies were normally abundant and the perinuclear membrane masses were not present.
Rat Brain: Effects of Environmental Enrichment on Wet and Dry Weights
Authors: Bennett Edward L. , Rosenzweig Mark R. , Diamond Marian C.
Published: October 2006

Wet weight of rat cerebral cortex was increased by exposure to an enriched environment, as compared with standard colony or impoverished conditions. Dry weights and wet weights were compared and both yielded identical percentage differences between brains of animals experiencing enrichment and those experiencing impoverishment.
Meteorite Fail at Pueblito de Allende, Chihuahua, Mexico: Preliminary Information
Authors: King E. A. , Schonfeld E. , Richardson K. A. , Eldridge J. S.
Published: October 2006

Specimens from the meteorite fall at 1:05 a.m., on 8 February 1969 at Pueblito de Allende, Chihuahua, Mexico, have been recovered. The meteorite is a chondrite (C3 and C4) with both opaque and microcrystalline matrices. Specimens were brought to a low background gamma counter less than 4½ days after the fall, and gamma rays from short-lived isotopes have been observed.
25-Hydroxycholecalciferol: Stimulation of Bone Resorption in Tissue Culture
Authors: Trummel C. L. , Raisz L. G. , Blunt J. W. , Deluca H. F.
Published: October 2006

25-Hydroxycholecalciferol stimulates release of previously incorporated calcium-45 from fetal rat bones in doses of 0.9 to 27 units per milliliter. This effect cannot be produced by much larger doses of vitamin D
3
. Comparison of stimulation of bone resorption by 25-hydroxycholecalciferol and parathyroid hormone reveals similarities with respect to time course, dose-response slope, and inhibition by calcitonin.
Peptide Binding by Chaperone SecB: Implications for Recognition of Nonnative Structure
Authors: Randall Linda L.
Published: October 2006

The molecular basis for recognition of nonnative proteins by the molecular chaperone SecB was investigated with an in vitro assay based on the protection of SecB from proteolysis when a ligand is bound. The SecB tetramer has multiple binding sites for positively charged peptides. When the peptide binding sites are occupied, the complex undergoes a conformational change to expose hydrophobic sites that bind the fluorescent probe 1-anilinonaphthalene-8-sulfonate. A model is proposed for interaction of nonnative polypeptides with both hydrophilic and hydrophobic sites on SecB.
Three-Dimensional Structure of an Angiotensin II-Fab Complex at 3 Å: Hormone Recognition by an Anti-Idiotypic Antibody
Authors: Garcia K. Christopher , Ronco Pierre M. , Verroust Pierre J. , Brünger Axel T. , Amzel L. Mario
Published: October 2006

The elucidation of bioactive conformations of small peptide hormones remains an elusive goal to structural chemists because of the inherent flexibility of these molecules. Angiotensin II (AII), the major effector of the renin-angiotensin system, is an octapeptide hormone for which no clear structural models exist. Peptide hormones such as AII share the property that they bind to their receptors with high affinities, in spite of the fact that they must overcome an extremely large conformational entropy barrier to bind in one conformation. A "surrogate system" that consists of a high-affinity monoclonal antibody (MAb) and AII has been used to study a bound conformation of AII. The crystallographic structure of the complex reveals a structure of AII that is compatible with predicted bioactive conformations of AII derived from structure-activity studies and theoretical calculations. In the complex, the deeply bound hormone is folded into a compact structure in which two turns bring the amino and carboxyl termini close together. The antibody of this complex (MAb 131) has the unusual property that it was not generated against AII, but rather against an anti-idiotypic antibody reactive with a MAb to AII, which renders this antibody an anti-anti-idiotypic antibody. The high affinity for AII of the original MAb to AII was passed on to MAb 131 through a structural determinant on the anti-idiotypic antibody. Strikingly, the conformation of AII in this complex is highly similar to complementarity determining region loops of antibodies, possibly indicating that a true molecular mimic of bound AII was present on the anti-idiotypic antibody against which MAb 131 was elicited.
An Eosinophil-Dependent Mechanism for the Antitumor Effect of Interleukin-4
Authors: Tepper Robert I. , Coffman Robert L. , Leder Philip
Published: October 2006

Murine interleukin-4 (IL-4) exhibits potent antitumor activity when present at the site of tumor cell challenge. Associated with tumor cell death is the appearance of an inflammatory infiltrate comprised predominantly of eosinophils and macrophages, but with few lymphocytes. Antibodies that specifically block the accumulation of granulocytes at the site of inflammation were injected in vivo to define the cell type responsible for the antitumor action of IL-4. These studies implicate eosinophils in IL-4-mediated tumor cytotoxicity. The lymphoid-independent nature of IL-4 action is supported by the analysis of mutant mouse strains with defined lymphocyte immunodeficiencies. The observed regression of established tumor masses by localized IL-4 action provides a rationale for exploring IL-4-mediated tumor killing as a potential therapy for human malignant disorders.
Attention Reduction and Suppressed Direct-Current Potentials in the Human Brain
Authors: Tecce Joseph J. , Scheff Neil M.
Published: October 2006

Distraction suppresses direct-current potentials (contingent negative variation) recorded from the human scalp. This reduction is accompanied by retarded reaction time. Contingent negative variation and reaction time appear to reflect a common process, attention.
Encephalic Cycles during Sleep and Wakefulness in Humans: A 24-Hour Pattern
Authors: Othmer Ekkehard , Hayden Mary P. , Segelbaum Robert
Published: October 2006

Twenty-four-hour polygraphic tracings from normal humans indicate that a pattern of alternating periods of the presence and absence of rapid eye movement, shown to exist for normal sleep, exist over all 24 hours of the daily period. This finding suggests that the so-called sleep-dream cycle of human sleep is not specific to sleep, but is a general activity pattern of the brain.
Fissioning in Planarians: Control by the Brain
Authors: Best J. B. , Goodman A. B. , Pigon A.
Published: October 2006

Reduced population densities lead to increased rates of fissioning in planarians whereas higher population densities suppress fissioning. This effect is not primarily due to mucus deposition or substances secreted into the water. Experiments are presented which show a system of population feedback control. In the presence of other planarians, the brain exerts an influence (probably neurohormonal) to suppress fissioning. This influence becomes attenuated with axial distance from the brain.
DDT Residues Absorbed from Organic Detritus by Fiddler Crabs
Authors: Odum W. E. , Woodwell G. M. , Wurster C. F.
Published: October 2006

DDT and its metabolites accumulate in organic plant detritus within estuaries and may persist there for many years. The residues appear to be most abundantly associated with particulates having diameters from 250 to 1000 microns. Detritus particles of this size are ingested by many organisms, and associated DDT residues may enter diverse food chains. Fiddler crabs
Uca pugnax
were fed natural detritus containing DDT residues (10 parts per million) during an 11-day experiment and showed grossly modified behavior associated with a threefold increase in concentration of DDT residues in the muscle of the large claw.
Strontium-90: Concentrations in Surface Waters of the Atlantic Ocean
Authors: Bowen Vaughan T. , Noshkin Victor E. , Volchok Herbert L. , Sugihara Thomas T.
Published: October 2006

From the large body of analyses of strontium-90 in surface waters of the Atlantic Ocean, annual average concentrations (from 10°N to 70°N) have been compared to those predicted. The data indicate higher fallout over ocean than over land and confirm the rapid rates of down-mixing shown by most studies of subsurface strontium-90.
Aphid Transmission of Tobacco Mosaic Virus
Authors: Lojek John S. , Orlob Gert B.
Published: October 2006

Aphids (
Myzus persicae
Sulz.) can acquire tobacco mosaic virus from tobacco leaves coated with a virus suspension and inoculate it into healthy leaves. Transmission depends on virus concentration, period of acquisition, previous feeding history of the aphids, and time between acquisition and transmission feedings. Aphids whose stylets are cut do not transmit the virus.
Cytophaga
That Kills or Lyses Algae
Authors: Stewart James Ray , Brown R. Malcolm
Published: October 2006

A myxobacterium (
Cytophaga N-5
) isolated from sewage kills or lyses an array of living green and blue-green algae. When assayed with
Nostoc muscorum
or
Plectonema boryanum
, plaques form like those caused by the blue-green algal virus LPP-1. This isolate lyses or inhibits mutually Gram-positive and Gram-negative eubacteria.
Azurin: X-Ray Data for Crystals from
Pseudomonas denitrificans
Authors: Strahs Gerald
Published: October 2006

Azurin, a blue-colored copper protein, from a soil bacteria,
Pseudomonas denitrificans
, has been crystallized and its molecular weight of 16,000 was confirmed by means of x-ray diffraction.
Hormonal Induction of Increased Zinc Uptake in Mammalian Cell Cultures: Requirement for RNA and Protein Synthesis
Authors: Cox Rody P.
Published: October 2006

The zinc content of HeLa S
3
cells is markedly increased after growth in medium containing adrenal glucocorticoid hormones. Studies with inhibitors indicate that the synthesis of RNA and protein is required for enhanced zinc uptake. When protein synthesis is blocked in the presence of the steroid, an intermediate, presumably messenger RNA, which specifies enhanced zinc uptake accumulates and is expressed when the inhibition of protein synthesis is removed.
Virus-like Antigen, Antibody, and Antigen-Antibody Complexes in Hepatitis Measured by Complement Fixation
Authors: Shulman N. Raphael , Barker Lewellys F.
Published: October 2006

Complement fixation techniques are described for measuring a virus-like antigen associated with viral hepatitis. Antigen was found in the blood of 98 percent of 130 patients, with the serum form of hepatitis, from whom multiple samples were obtained. Antibodies arising during hepatitis are usually combined with antigen and cause anticomplementary activity in the serum, which is reversible with excess antigen or antibody. Tests for antigen and specific anticomplementary activity can be used diagnostically and to screen blood donors for hepatitis carriers.
Solar Cycle Variation of Exospheric Temperatures Mars and Venus: A Prediction for Mariner 6 and 7
Authors: Stewart Richard W. , Hogan Joseph S.
Published: October 2006

Calculations have been made to determine the effects of variations in the extreme ultraviolet solar radiation on the upper atmospheres of Mars and Venus. The results indicate that the exospheric temperature on Mars varies from 300°K to 600°K during the solar cycle, with a corresponding range on Venus of 450°K to 850°K. At the present time, the temperature of the Martian exosphere should be approximately 500°K.
Sex Pheromone Specificity: Taxonomic and Evolutionary Aspects in Lepidoptera
Authors: Roelofs Wendell L. , Comeau Andre
Published: October 2006

Sex pheromone specificity is the only obvious reproduction isolating mechanism for two tortricid species and two gelechiid species. Pheromones of the gelechiid species are
cis
-9-tetradecenyl acetate and
trans
-9-tetradecenyl acetate. Male response of one gelechiid species is inhibited by the pheromone of the other species. This could be important for sympatric evolutionary saltation.
Inhibition of Neointimal Smooth Muscle Accumulation After Angioplasty by an Antibody to PDGF
Authors: Ferns Gordon A. A. , Raines Elaine W. , Sprugel Katherine H. , Motani Alykhan S. , Reidy Michael A. , Ross Russel
Published: October 2006

Approximately 30 to 40 percent of atherosclerotic coronary arteries treated by angioplasty or by bypass surgery occlude as a result of restenosis. This restenosis is due principally to the accumulation of neointimal smooth muscle cells, which is also a prominent feature of the advanced lesions of atherosclerosis. The factors responsible for the accumulation of intimal smooth muscle cells have not been identified. Platelet-derived growth factor (PDGF) is a potent smooth muscle chemoattractant and mitogen. It is present in platelets and can be formed by endothelium, smooth muscle, and monocyte-derived macrophages. The development of an intimal lesion in the carotid artery of athymic nude rats induced by intraarterial balloon catheter deendothelialization was inhibited by a polyclonal antibody to PDGF. These data demonstrate that endogenous PDGF is involved in the accumulation of neointimal smooth muscle cells associated with balloon injury and may be involved in restenosis after angioplasty, and perhaps in atherogenesis as well.
Hepatic Influence on Splenic Synthesis and Release of Coagulation Activities
Authors: Dodds W. J.
Published: October 2006

Isolated rabbit liver perfusates contain one or more puromycinsensitive factors that stimulate factor VIII and IX activities in splenic perfusates. Production of coagulation activity by a complementary process involving organ perfusates suggests existence of coagulation factor precursors. An analogy is made to appearance of high factor VIII activity after plasma transfusions in von Willebrand's disease.
Radionuclide Composition of the Allende Meteorite from Nondestructive Gamma-Ray Spectrometric Analysis
Authors: Rancitelli L. A. , Perkins R. W. , Cooper J. A. , Kaye J. H. , Wogman N. A.
Published: October 2006

The concentrations of beryllium-7, sodium-22, aluminum-26, potassium-40, scandium-46, vanadium-48, chromium-51, manganese-54, cobalt-57, cobalt-60, and thorium-232 (thallium-208) have been measured in the Allende meteorite by nondestructive gamma-ray spectrometry. The high cobalt-60 content of the meteorite is indicative of a preatmospheric body with a minimum effective radius of 50 centimeters and a weight of 1650 kilograms; the aluminum-26 activity indicates a minimum exposure age of 3 million years.
Physical and Chemical Studies on Ceruloplasmin: Crystallization of Desialized Human Ceruloplasmin Asialoceruloplasmin
Authors: Morell Anatol G. , Sternlieb Irmin , Scheinberg I. Herbert
Published: October 2006

Completely or partially desialized human ceruloplasmin crystallizes as blue hexagonal prisms terminating at both ends in shallow pyramids.
Pathotoxin-Induced Disease Resistance in Plants
Authors: Wheeler Harry , Pirone Thomas P.
Published: October 2006

Primary leaves of bean plants treated with nonphytotoxic concentrations of the pathotoxin victorin were rendered highly resistant to two plant viruses. Leaves treated with higher concentrations of victorin became necrotic. These effects on plants that are resistant to victorin and to the fungus that produces it lend support to the hypothesis that activation of a defensive self-repair mechanism may account for resistance to this highly selective pathotoxin.
Potassium Ions Asymmetrically Activate Erythrocyte Membrane Phosphatase
Authors: Rega Alcides F. , Pouchan María I. , Garrahan Patricio J.
Published: October 2006

In reconstituted ghosts of human red cells, the cell membrane phosphatase is activated by external, but not by internal, potassium. This finding is consistent with the possible participation of the membrane phosphatase in the enzymatic system responsible for cation transport.
Reactivity in vivo of the Carcinogen
N
-Hydroxy-2-acetylaminofluorene: Increase by Sulfate Ion
Authors: DeBaun Jack R. , Smith Jacqueline Y. R. , Miller Elizabeth C. , Miller James A.
Published: October 2006

Injections of sulfate ion in rats given the carcinogen
N
-hydroxy-2-acetylaminofluorene increased (i) the formation of 1- and 3-(methion-S-yl)-2-acetylaminofluorene bound to protein in the liver, (ii) the formation of fluorenyl derivatives bound to total protein, ribosomal RNA, and DNA in the liver, and (iii) the toxicity of the carcinogen. These data provide evidence that the highly reactive ester 2-acetylaminofluorene-
N
-sulfate, previously suggested as an ultimate reactive and carcinogenic metabolite of
N
-hydroxy-2-acetylaminofluorene, is formed in the rat liver in vivo.
Olfactory Bulb Removal Eliminates Mating Behavior in the Male Golden Hamster
Authors: Murphy Michael R. , Schneider Gerald E.
Published: October 2006

Mating behavior in sexually naive and sexually experienced male golden hamsters was totally eliminated by removing their olfactory bulbs. In contrast, the mating behavior in blinded, unilaterally bulbectomized, and sham-operated controls was essentially normal. Testosterone injections restored normal sexual behavior in castrated controls but had no effect on the bilaterally bulbectomized animals.
Argon-40/ Argon-39 Dating of Lunar Rock Samples
Authors: Turner Grenville
Published: October 2006

Seven crystalline rock samples returned by Apollo 11 have been analyzed in detail by means of the
40
Ar-
39
Ar dating technique. The extent of radiogenic argon loss in these samples ranges from 7 percent to ≥ 48 percent. Potassium-argon ages, corrected for the effects of this loss, cluster relatively closely around the value of 3.7 × 10
9
years. Most of the vulcanism associated with the formation of the Mare Tranquillitatis presumably occurred around 3.7 × 10
9
years ago. A major cause of the escape of gas from lunar rock is probably the impact event which ejected the rock from its place of origin to its place of discovery. Upper limits for the times at which these impact events occurred have been estimated.
Elemental Composition of Lunar Surface Material
Authors: Smales A. A. , Mapper D. , Webb M. S. W. , Webster R. K. , Wilson J. D.
Published: October 2006

Elemental abundances, so far obtained, derived from the analysis of Apollo 11 lunar material are reported. Similarities and differences exist between lunar material, the eucritic achondrites, and the augite achondrite Angra dos Reis, the analysis of which is also reported.
Isotopic Analysis of Rare Gases from Stepwise Heating of Lunar Fines and Rocks
Authors: Reynolds J. H. , Hohenberg C. M. , Lewis R. S. , Davis P. K. , Kaiser W. A.
Published: October 2006

Highlights of a first effort in sorting out rare gases in lunar material are solar wind rare gases in abundance; variable
20
Ne/
22
Ne but constant
21
Ne/
22
Ne ratios in fractions of the trapped neon; cosmogenic rare gases similar to those found in meteorites, except for copious
131
Xe in one rock but not in another; at Tranquillity Base a rock 4.1 × 10
9
years old which reached the surface 35 to 65 million years ago, amid soil whose particles have typically been within a meter of the surface for 10
9
years or more.
Iron-Titanium Oxides and Olivine from 10020 and 10071
Authors: Haggerty S. E. , Boyd F. R. , Bell P. M. , Finger L. W. , Bryan W. B.
Published: October 2006

A new mineral (approximately Fe
0.5
Mg
0.5
Ti
2
O
5
) related to the pseudobrookite series has been discovered in section 10071,28. Electron-probe analyses for this mineral, a coexisting ilmenite, and a chromian ulvöspinel-ilmenite assemblage in section 10020,40 indicate crystallization under highly reducing conditions. Analytical and optical absorption studies of the olivine in 10020 show it to contain unusually high Cr (1400 parts per million) probably as Cr
2+
.
Micropaleontological Studies of Lunar Samples
Authors: Schopf J. William
Published: October 2006

Optical and electron microscopic studies of rock chips and dust from the bulk sample box returned by Apollo 11 and of petrographic thin sections and acid-resistant residues of lunar material have yielded no evidence of indigenous biological activity.
Radon-222 in the North Atlantic Trade Winds: Its Relationship to Dust Transport from Africa
Authors: Prospero Joseph M. , Carlson Toby N.
Published: October 2006

The concentration of radon-222 in air was measured during a flight from Miami to Barbados to Dakar and return; concentrations ranged from 1 to 55 picocuries per standard cubic meter of air and were highest in areas of dense haze, which were present along most of the flight path across the Atlantic Ocean. The haze is attributed to dust originating from the arid regions of western Africa. Radon-222 may be useful as a tracer for African air parcels over the equatorial Atlantic.
Endogenous Carbon in Carbonaceous Meteorites
Authors: Smith J. W. , Kaplan I. R.
Published: October 2006

Seven carbonaceous chondrites have been analyzed for soluble organic compounds, carbonate, and residual carbon. Carbon-13/carbon-12 isotopic measurements on these fractions gave the following values relative to a marine carbonate standard: carbonate, +40 to +70 per mil; residual carbon, -15 to -17 per mil; soluble organic material, -17 to -27 per mil, with one value of -5.5 per mil. These values are interpreted to indicate that carbonate, residual carbon, and part of the extractable organic material are endogenous to these meteorites.
A Genetic Model for Interaction of the Homeodomain Recognition Helix with DNA
Authors: Hanes Steven D. , Brent Roger
Published: October 2006

The Bicoid homeodomain protein controls anterior development in the Drosophila embryo by binding to DNA and regulating gene expression. With the use of genetic assays in yeast, the interaction between the Bicoid homeodomain and a series of mutated DNA sites was studied. These experiments defined important features of homeodomain binding sites, identified specific amino acid-base pair contacts, and suggested a model for interaction of the recognition α-helices of Bicoid and Antennapedia-class homeodomain proteins with DNA. The model is in general agreement with results of crystallographic and magnetic resonance studies, but differs in important details. It is likely that genetic studies of protein-DNA interaction will continue to complement conventional structural approaches.
Linkage of a Cardiac Arrhythmia, the Long QT Syndrome, and the Harvey
ras
-1 Gene
Authors: Keating Mark , Atkinson Donald , Dunn Christine , Timothy Katherine , Vincent G. Michael , Leppert Mark
Published: October 2006

Genetic factors contribute to heart disease. In this study, linkage analyses have been performed in a family that is predisposed to sudden death from cardiac arrhythmias, the long QT syndrome (LQT). A DNA marker at the Harvey
ras
-1 locus (H-
ras
-1) was linked to LQT with a logarithm of the likelihood ratio for linkage (lod score) of 16.44 at θ = 0, which confirms the genetic basis of this trait and localizes this gene to the short arm of chromosome 11. As no recombination was observed between LQT and H-
ras
-1, and there is a physiological rationale for its involvement in this disease,
ras
becomes a candidate for the disease locus.