bluuebunny/crossref_metadata_2025 huggingface dataset:
The Skeletal Muscle Chloride Channel in Dominant and Recessive Human Myotonia
Authors: Koch Manuela C. , Steinmeyer Klaus , Lorenz Claudius , Ricker Kenneth , Wolf Friedrich , Otto Michael , Zoll Barbara , Lehmann-Horn Frank , Grzeschik Karl-Heinz , Jentsch Thomas J.
Published: October 2006

Autosomal recessive generalized myotonia (Becker's disease) (GM) and autosomal dominant myotonia congenita (Thomsen's disease) (MC) are characterized by skeletal muscle stiffness that is a result of muscle membrane hyperexcitability. For both diseases, alterations in muscle chloride or sodium currents or both have been observed. A complementary DNA for a human skeletal muscle chloride channel (
CLC
-1) was cloned, physically localized on chromosome 7, and linked to the T cell receptor β (
TCRB
) locus. Tight linkage of these two loci to GM and MC was found in German families. An unusual restriction site in the
CLC
-1 locus in two GM families identified a mutation associated with that disease, a phenylalanine-to-cysteine substitution in putative transmembrane domain D8. This suggests that different mutations in
CLC
-1 may cause dominant or recessive myotonia.
Detection of Antibodies in Blood Meals of Hematophagous Diptera
Authors: Cunningham M. P. , Harley J. M. B. , Southon H. A. W. , Lumsden W. H. R.
Published: October 2006

Antibodies are detectable by an agglutination technique in the blood meals of hematophagous Diptera that are fed on laboratory and domestic animals infected with organisms of the
Trypanosoma brucei
subgroup. It is likely that both the antibody status and the identity of the animal fed on can be determined from the same blood meal from wild Diptera. The technique may be applicable to other infections for which sensitive serological tests are available.
Australites and Antarctica
Authors: Schmidt Richard A.
Published: October 2006

A meteorite crater in the Wilkes Land region of Antarctica has been postulated as an explanation of the origin of australites. Geophysical data suggest that such a feature may have been located.
Fate of a Synthetic Polynucleotide Directing Cell-Free Protein Synthesis II. Association with Ribosomes
Authors: Barondes Samuel H. , Nirenberg Marshall W.
Published: October 2006

Tritiated-poly U, when added to cell-free extracts of
Escherichia coli
, became associated with ribosomes. This association occurred at 3°C and did not require high-energy phosphate compounds. Small amounts of tritiated polyuridylic acid produced polydisperse ribosomal aggregates with sedimentation constants of approximately 100 to 130. C
14
-phenylalanine initially was incorporated into protein only on these particles, which suggests that they are the sites of polyphenylalanine synthesis.
Penicillinase Production in Some Bacilli
Authors: Day Richard A. , Shah Ramesh
Published: October 2006

Penicillinase production in strains of bacillus in which such production is constitutive, as well as in strains in which it is inducible, was found to be a function of the type of penicillin to which the organism was exposed. A repressive effect in two constitutive strains was noted. An increase in the level of penicillinase produced by the constitutive strains was noted for some of the penicillins.
Recovery from Radiation-Induced Delay of Cleavage in Gametes of
Arbacia punctulata
Authors: Failla Patricia McClement
Published: October 2006

A decrease in delay of cleavage, when irradiated sperm from
Arbacia punctulata
were allowed to "recover" inside eggs, occurred when cell division was interrupted by the removal of oxygen soon after fertilization. The recovery mechanisms in irradiated eggs of this species before and after fertilization have been compared and appear to differ.
Hyperalgesia Mediated by Spinal Glutamate or Substance P Receptor Blocked by Spinal Cyclooxygenase Inhibition
Authors: Malmberg A. B. , Yaksh T. L.
Published: October 2006

Inhibition of cyclooxygenase by nonsteroidal anti-inflammatory drugs (NSAIDs) in the periphery is commonly accepted as the primary mechanism by which these agents produce a selective attenuation of pain (analgesia). NSAIDs are now shown to exert a direct spinal action by blocking the excessive sensitivity to pain (hyperalgesia) induced by the activation of spinal glutamate and substance P receptors. These findings demonstrate that the analgesic effects of NSAIDs can be dissociated from their anti-inflammatory actions. Spinal prostanoids are thus critical for the augmented processing of pain information at the spinal level.
Control by Asparagine Residues of Calcium Permeability and Magnesium Blockade in the NMDA Receptor
Authors: Burnashev Nail , Schoepfer Ralf , Monyer Hannah , Ruppersberg J. Peter , Günther Willy , Seeburg Peter H. , Sakmann Bert
Published: October 2006

The
N
-methyl-D-aspartate (NMDA) receptor forms a cation-selective channel with a high calcium permeability and sensitivity to channel block by extracellular magnesium. These properties, which are believed to be important for the induction of long-term changes in synaptic strength, are imparted by asparagine residues in a putative channel-forming segment of the protein, transmembrane 2 (TM2). In the NR1 subunit, replacement of this asparagine by a glutamine residue decreases calcium permeability of the channel and slightly reduces magnesium block. The same substitution in NR2 subunits strongly reduces magnesium block and increases the magnesium permeability but barely affects calcium permeability. These asparagines are in a position homologous to the site in the TM2 region (Q/R site) of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors that is occupied by either glutamine (Q) or arginine (R) and that controls divalent cation permeability of the AMPA receptor channel. Hence AMPA and NMDA receptor channels contain common structural motifs in their TM2 segments that are responsible for some of their ion selectivity and conductance properties.
Discrimination of Successiveness: A Test of a Model of Attention
Authors: Schmidt Marianne W. , Kristofferson Alfred B.
Published: October 2006

Interpreting attention as a periodic phenomenon, we show its relevance to discriminating the successiveness of signals presented to separate sense modalities. Experiments confirm the expected linear relation between the probability of discriminating pairs of successive from pairs of simultaneous signals and make it possible to infer the period of attention.
Amino Acids in the Proteins from Aragonite and Calcite in the Shells of
Mytilus californianus
Authors: Hare P. Edgar
Published: October 2006

Hydroxylysine and hydroxyproline are absent in the calcified proteins of
Mytilus
. The organic matrices from the calcite layers have a consistently higher ratio of acidic to basic amino acids than the aragonitic shell units. The uncalcified shell units periostracum and outer ligament, have very few acidic residues, which may in part account for the lack of mineralization.
Fractionation of Sulfur and Carbon Isotopes in a Meromictic Lake
Authors: Deevey Edward S. , Nakai Noboyuki , Stuiver Minze
Published: October 2006

In the permanently stagnant depths of Green Lake (near Syracuse, N.Y.), sulfide made by bacteria is depleted in heavy sulfur (S
34
), and sulfate is enriched. The fractionation factor, 1.0575, is the greatest yet observed. Isotopic resemblance to salt-dome sulfur deposits is evident, and, like saltdome calcite, the lake's carbon dioxide is depleted in heavy carbon (C
13
).
Lactic and Malic Dehydrogenases in Human Spermatozoa
Authors: Goldberg Erwin
Published: October 2006

Human spermatozoa, representing a homogeneous population of postmitotic cells, contain five electrophoretically distinct lactic dehydrogenases and two malic dehydrogenases. This indicates that molecular heterogeneity of enzymes is characteristic of the individual cell and is not a reflection of heterogeneity of cell types within a tissue.
Density-Gradient Separation of Organic and Inorganic Particles by Centrifugation
Authors: Lammers W. T.
Published: October 2006

Aqueous suspensions of particulate organic and inorganic material were centrifuged in a 2-bromoethanol density gradient. The degree of separation with this new technique is superior to that achieved with sucrose density gradients.
Tarichatoxin: Isolation and Purification
Authors: Brown Melancthon S. , Mosher Harry S.
Published: October 2006

The potent neurotoxin occurring in the embryos of the California newt,
Taricha torosa
, has been obtained in crystalline form. With a lethal subcutaneous dose of approximately 0.14 micrograms for a 20-gram mouse, it is, along with saxitoxin and tetrodotoxin, one of the most toxic nonprotein substances known.
Scavenger Probe Sampling: A Method for Studying Gaseous Free Radicals
Authors: Fristrom R. M.
Published: October 2006

Scavenger probe sampling for determining the concentration of certain gaseous free radicals and atoms has been used to study flames and electric discharges. Combining microprobe sampling and chemical scavenging with mass spectral analysis, this technique offers high spatial resolution, absolute concentration determination, and high temperature applicability. The reactions of hydrogen atoms with chlorinated hydrocarbons and oxygen atoms with nitrogen dioxide were used for scavenging. The results were reproducible and proportional to concentration. In an electric discharge oxygen atom concentrations agreed with gas phase titration determinations. The gas phase titration measures atom flux rather than concentration, and differences as high as 20 percent were observed. A method for deriving concentration from flux measurements is discussed.
Adipose Tissue: Ability to Respond to Nerve Stimulation in vitro
Authors: Correll James W.
Published: October 2006

Electrical stimulation of nerves to isolated rat and rabbit adipose tissue in vitro causes production of free fatty acids. Starvation increases the response. The response of white (epididymal) fat is prevented by sympathetic denervation. Direct evidence is provided showing that adipose tissue has the capacity to be an effector organ responsive to the nervous system.
Schistosoma mansoni
: Development of Challenge Infections in Mice Exposed to Irradiated Cercariae
Authors: Szumlewicz Alina Perlawagora , Olivier Louis J.
Published: October 2006

The principal effect of x-irradiated
Schistosoma mansoni
cercariae may be to slow the migration and development of the worms of a challenge infection. This would account for the smaller number of worms found in the portal system in the early weeks and the delayed accumulation of recoverable worms and eggs.
Oxygen-Carrying Properties of a Simple Synthetic System
Authors: Vaska L.
Published: October 2006

An iridium compound, chloro-carbonyl-
bis
(triphenylphosphine)-iridium, in solution, takes up molecular oxygen—one molecule per metal atom—which is subsequently recovered by reducing the pressure. The adduct is photosensitive but otherwise stable at ambient temperatures. It is a monomeric molecular complex and probably contains a peroxo group with both oxygens bonded to the same metal atom.
Mammalian X-Chromosome Action: Inactivation Limited in Spread and in Region of Origin
Authors: Russell Liane Brauch
Published: October 2006

In its simplest form the hypothesis of the single-active-X chromosome does not explain variegated-type position effects in the mouse. Inactivity appears not to involve one entire X chromosome; furthermore, even those parts of the chromosome that can change to an inactive state spread inactivation not to the entire attached piece of autosome, but along a gradient to limited distances.
Lactate Dehydrogenase Isozymes: Dissociation and Recombination of Subunits
Authors: Markert Clement L.
Published: October 2006

Lactate dehydrogenase from beef tissues may be resolved electrophoretically into five isozymes each of which is a tetramer. These tetramers can be dissociated into monomers by freezing in 1
M
sodium chloride. On thawing, reassociation into functional tetramers occurs. On the basis of charge and amino acid composition there are two kinds of monomers. Lactate dehydrogenase-1 contains one kind of monomer and lactate dehydrogenase-5 the other kind. A mixture of equal quantities of these two isozymes, after dissociation and reassociation, leads to the production of all five isozymes in the expected proportions of 1:4:6:4:1.
Photoperiodism: An Effect of Darkness during the Light Period on Critical Night Length
Authors: Hillman William S.
Published: October 2006

The critical night length of the short-day plant
Lemna perpusilla
, grown with sucrose, increases roughly 3 hours under cycles with "light periods" composed of darkness preceded and ended by brief exposures to light. Although plants so grown are white, the effect is due neither to the absence of photosynthesis nor to insufficient total energy. It is inconsistent with current ideas on photoperiodic timing but may be explained by a hypothesis based on reported properties of phytochrome.
Morphogenesis of Syncytiotrophoblast in vivo: An Autoradiographic Demonstration
Authors: Midgley A. R. , Pierce G. B. , Deneau G. A. , Gosling J. R. G.
Published: October 2006

In an in vivo autoradiographic study of immature primate trophoblast, tritiated thymidine was first found only in nuclei of cytotrophoblast but after 22 hours, labeled nuclei appeared in syncytiotrophoblast as well. Hence syncytiotrophoblast of the monkey appears to originate by differentiation of cytotrophoblast.
Epizootic Diarrhea of Infant Mice: Identification of the Etiologic Agent
Authors: Adams W. R. , Kraft L. M.
Published: October 2006

Electron micrographs of intestinal epithelium of infant mice infected with epizootic diarrhea virus have demonstrated intracellular spherical structures measuring 65 to 75 mμ in diameter which have a complex morphology resembling several virus particles. They have been interpreted as being the etiologic agent of this disease. The particles were present in association with, in some cases within, vesicles of the endoplasmic reticulum of intestinal epithelial cells. They were never seen in the nucleus.
Bioelectric Activity in Long-Term Cultures of Spinal Cord Tissues
Authors: Crain Stanley M. , Peterson Edith R.
Published: October 2006

Fragments of embryonic spinal cord (human, rat, and chick) can regenerate and differentiate in tissue culture. Complex bioelectric activity evoked by electric stimuli indicates that nerve cells in cultures may maintain, for months in vitro, not only the capacity to propagate impulses along their neurites but also a remarkable degree of functional organization resembling the activity of synaptic networks of the central nervous system.
Potentiation of 5-Fluorouracil Inhibition of Flexner-Jobling Carcinoma by Glucose
Authors: Kung Shiu-shia , Goldberg Nelson D. , Dahl June L. , Parks R. E. , Kline B. E.
Published: October 2006

A significant potentiation of the antitumor action of 5-fluorouracil in rats bearing the Flexner-Jobling carcinoma is produced by the intraperitoneal administration of large doses of glucose.
Eyeball Retraction: Classical Conditioning and Extinction in the Albino Rabbit
Authors: Deaux Edward B. , Gormezano I.
Published: October 2006

A comparison of the percentage-performance curve of a classical conditioning group with those of three control groups provided unequivocal evidence of successful conditioning of the retractor bulbi response to an auditory conditioned stimulus.
Intercellular Propagation of Calcium Waves Mediated by Inositol Trisphosphate
Authors: Boitano Scott , Dirksen Ellen R. , Sanderson Michael J.
Published: October 2006

Two types of calcium (Ca
2+
) signaling-propagating intercellular Ca
2+
waves of increasing intracellular Ca
2+
concentration ([Ca
2+
]
i
) and nonpropagating oscillations in [Ca
2+
]
i
-co-exist in a variety of cell types. To investigate this difference in Ca
2+
signaling, airway epithelial cells were loaded with heparin, an inositol 1,4,5-trisphosphate (IP
3
) receptor antagonist, by pulsed, high-frequency electroporation. Heparin inhibited propagation of intercellular Ca
2+
waves but not oscillations of [Ca
2+
]
i
. In heparin-free cells, Ca
2+
waves propagated through cells displaying [Ca
2+
]
i
oscillations. Depletion of intracellular Ca
2+
pools with the Ca
2+
-pump inhibitor thapsigargin also inhibited the propagation of Ca
2+
waves. These studies demonstrate that the release of Ca
2+
by IP
3
is necessary for the propagation of intercellular Ca
2+
waves and suggest that IP
3
moves through gap junctions to communicate intercellular Ca
2+
waves.
Phase Coupling by Synaptic Spread in Chains of Coupled Neuronal Oscillators
Authors: Williams Thelma L.
Published: October 2006

Many neural systems behave as arrays of coupled oscillators, with characteristic phase coupling. For example, the rhythmic activation patterns giving rise to swimming in fish are characterized by a rostral-to-caudal phase delay in ventral root activity that is independent of the cycle duration. This produces a traveling wave of curvature along the body of the animal with a wavelength approximately equal to the body length. Here a simple mechanism for phase coupling in chains of equally activated oscillators is postulated: the synapses between the cells making up a "unit oscillator" are simply repeated in neighboring segments, with a reduced synaptic strength. If such coupling is asymmetric in the rostral and caudal directions, traveling waves of activity are produced. The intersegmental phase lag that develops is independent of the coupling strength over at least a tenfold range. Furthermore, for the unit oscillator believed to underlie central pattern generation in the lamprey spinal cord, such coupling can result in a phase lag that is independent of frequency.
Muscle: Volume Changes in Isolated Single Fibers
Authors: Reuben J. P. , Lopez E. , Brandt P. W. , Grundfest H.
Published: October 2006

Volumetric experiments on single fibers isolated from semitendinosus muscles of frogs, some performed in correlation with measurements of membrane potential, confirm the data obtained on whole muscles, but only for the specific range of conditions in which most of the latter experiments have been done. These conditions are restricted to media in which the anion (Cl usually) is permanent and the K is 10 to 12.5 meq/liter, or four to five times above the normal level in Ringer's solution. When other ionic conditions are employed, phenomena are disclosed which have not previously been described. The findings throw doubt upon the validity of some generally accepted views regarding the permeability properties of the membrane of frog muscle fibers and regarding the nature of the mechanisms which regulate their volume.
High Pressure Phases of Some Compounds of Groups II-VI
Authors: Mariano A. N. , Warekois E. P.
Published: October 2006

The high pressure phases of the mercury and cadmium sulfides, selenides, and tellurides have been determined by means of x-ray diffraction patterns obtained while the materials are under pressure.
Galactose Metabolism by Rat Liver Tissue: Influence of Age
Authors: Segal Stanton , Roth Henry , Bertoli Dolores
Published: October 2006

The metabolism of galactose by liver tissue from fetal, new-born, pre-adult, and adult rats was studied in vitro by determining the extent of conversion of galactose to CO
2
and the disappearance of the sugar from the incubation medium. Results indicate that the utilization of galactose by liver tissue decreases as the organism grows older. The explanation of the tendency of patients with congenital galactosemia to improve symptomatically with age on the basis of "maturation" of galactose metabolizing pathways in their livers does not appear to be consistent with these observations.
Thymine Dimers and Inhibition of DNA Synthesis by Ultraviolet Irradiation of Cells
Authors: Setlow R. B. , Swenson P. A. , Carrier W. L.
Published: October 2006

Measurements of the inhibition of DNA synthesis in bacteria and the formation of thymine dimers by ultraviolet irradiation of the cells indicate that one thymine dimer per 350-μ strand of DNA acts as a block to further synthesis. In a sensitive strain of Escherichia coli the blocks are permanent. In a resistant strain the blocks are only temporary but recovery of synthesis is not the result of splitting dimers.
Tellurium Content of Marine Manganese Oxides and Other Manganese Oxides
Authors: Lakin H. W. , Thompson C. E. , Davidson D. F.
Published: October 2006

Tellurium in amounts ranging from 5 to 125 parts per million was present in all of 12 samples of manganese oxide nodules from the floor of the Pacific and Indian oceans. These samples represent the first recognized points of high tellurium concentration in a sedimentary cycle. The analyses may lend support to the theory that the minor-element content of sea-floor manganese nodules is derived from volcanic emanations.
Nucleolus: A Center of RNA Methylation
Authors: Birnstiel Max L. , Fleissner Erwin , Borek Ernest
Published: October 2006

The ubiquitously distributed complex of enzymes, the RNA methylases, the apparent function of which is the alteration of the structure of transfer RNA at the macromolecular level by the introduction of methyl groups into the component bases, are concentrated in the nucleolus, an organelle previously implicated in RNA synthesis.
Pleistocene Chipped Stone Tool on Santa Rosa Island, California
Authors: Orr Phil C.
Published: October 2006

Santa Rosa Island, California, has been the site of numerous discoveries of evidence of Pleistocene Man. The recent finding of a well-made chipped stone tool in situ in the mammoth beds adds further evidence.
Actinomycin D as a Probe for Nucleic Acid Secondary Structure
Authors: Haselkorn Robert
Published: October 2006

The binding of actinomycin D to DNA results in an increase in the temperature at which thermal dissociation of the DNA occurs. With this enhancement of thermal stability as a criterion for binding, it is shown that complementary RNA and DNA-RNA hybrid do not bind actinomycin D. This result can be interpreted to mean that these polynucleotides have helical conformations which differ from that of DNA.
Heterotransplantation of the Kidney: Two Clinical Experiences
Authors: Reemtsma Keith , McCracken Brian H. , Schlegel Jorgen U. , Pearl Maurice
Published: October 2006

The field of heterotransplantation is now being explored because of success with immunosuppressive measures in homotransplantation, and because of the scarcity of suitable human organs. Two patients in terminal uremia, maintained on dialysis, received heterotransplants from nonhuman primates. In the first case a renal heterotransplant from a rhesus monkey implanted in a 32-year-old woman showed satisfactory immediate function but was removed after 10 days because of inadequate function. The second patient received a renal heterotransplant from a chimpanzee. A threatened rejection was reversed with immunosuppressive measures, but 2 months after transplantation the patient died of pneumonia. The transplanted kidneys showed no evidence of rejection.
Multiple Authorship Trends in Scientific Papers
Authors: Clarke Beverly L.
Published: October 2006

Since 1946 biomedical writers have shown no marked trend toward multiple authorship; the average number of authors per paper remains steady at about 2.3. This is in strong contrast to the conclusion of Price from a study of
Chemical Abstracts
that the chemists' trend toward four or more authors per paper has been during this period, and continues to be, steeply exponential.
Homocystinuria: An Enzymatic Defect
Authors: Mudd S. Harvey , Finkelstein James D. , Irreverre Filadelfo , Laster Leonard
Published: October 2006

A deficiency, or absence, of cystathionine synthetase activity has been demonstrated in liver obtained from a mentally retarded child with homocystinuria.
The Human Y Chromosome: A 43-Interval Map Based on Naturally Occurring Deletions
Authors: Vollrath Douglas , Foote Simon , Hilton Adrienne , Brown Laura G. , Beer-Romero Peggy , Bogan Jonathan S. , Page David C.
Published: October 2006

A deletion map of the human Y chromosome was constructed by testing 96 individuals with partial Y chromosomes for the presence or absence of many DNA loci. The individuals studied included XX males, XY females, and persons in whom chromosome banding had revealed translocated, deleted, isodicentric, or ring Y chromosomes. Most of the 132 Y chromosomal loci mapped were sequence-tagged sites, detected by means of the polymerase chain reaction. These studies resolved the euchromatic region (short arm, centromere, and proximal long arm) of the Y chromosome into 43 ordered intervals, all defined by naturally occurring chromosomal breakpoints and averaging less than 800 kilobases in length. This deletion map should be useful in identifying Y chromosomal genes, in exploring the origin of chromosomal disorders, and in tracing the evolution of the Y chromosome.
Fatal Familial Insomnia and Familial Creutzfeldt-Jakob Disease: Disease Phenotype Determined by a DNA Polymorphism
Authors: Goldfarb Lev G. , Petersen Robert B. , Tabaton Massimo , Brown Paul , LeBlanc Andréa C. , Montagna Pasquale , Cortelli Pietro , Julien Jean , Vital Claude , Pendelbury William W. , Haltia Matii , Wills Peter R. , Hauw Jean J. , McKeever Paul E. , Monari Lucia , Schrank Bertold , Swergold Gary D. , Autilio-Gambetti Lucila , Gajdusek D. Carleton , Lugaresi Elio , Gambetti Pierluigi
Published: October 2006

Fatal familial insomnia (FFI) and a subtype of familial Creutzfeldt-Jakob disease (CJD), two clinically and pathologically distinct diseases, are linked to the same mutation at codon 178 (Asn
178
) of the prion protein gene. The possibility that a second genetic component modified the phenotypic expression of the Asn
178
mutation was investigated. FFI and the familial CJD subtype segregated with different genotypes determined by the Asn
178
mutation and the methionine-valine polymorphism at codon 129. The Met
129
, Asn
178
allele segregated with FFI in all 15 affected members of five kindreds whereas the Val
129
, Asn
178
allele segregated with the familial CJD subtype in all 15 affected members of six kindreds. Thus, two distinct disease phenotypes linked to a single pathogenic mutation can be determined by a common polymorphism.
The Nuclear Membrane
Authors: Dingwall Colin , Laskey Ronald
Published: October 2006

The nuclear membrane forms a major barrier within the cell, permitting levels of regulation not found in prokaryotes. The dynamics and diverse functions of the nuclear membrane and its associated structures are considered in this review. The role of the nuclear pore complex in selective transport across the nuclear membrane has been studied to a considerable degree; however, many crucial questions remain. Components of a signal transduction mechanism are associated with the nucleus, suggesting that nuclear functions may be influenced directly by this system. The involvement of the heat shock cognate protein Hsc70 in nuclear protein import is discussed, and a specific signal-presentation role for this protein is proposed.
Cytoskeleton—Plasma Membrane Interactions
Authors: Luna Elizabeth J. , Hitt Anne L.
Published: October 2006

Proteins at the boundary between the cytoskeleton and the plasma membrane control cell shape, delimit specialized membrane domains, and stabilize attachments to other cells and to the substrate. These proteins also regulate cell locomotion and cytoplasmic responses to growth factors and other external stimuli. This diversity of cellular functions is matched by the large number of biochemical mechanisms that mediate the connections between membrane proteins and the underlying cytoskeleton, the so-called membrane skeleton. General organizational themes are beginning to emerge from examination of this biochemical diversity.
Cooperativity Induced by a Single Mutation at the Subunit Interface of a Dimeric Enzyme: Glutathione Reductase
Authors: Scrutton Nigel S. , Deonarain Mahendra P. , Berry Alan , Perham Richard N.
Published: October 2006

When glycine
418
of
Escherichia coli
glutathione reductase, which is in a closely packed region of the dimer interface, is replaced with a bulky tryptophan residue, the enzyme becomes highly cooperative (Hill coefficient 1.76) for glutathione binding. The cooperativity is lost when the mutant subunit is hybridized with a wild-type subunit to create a heterodimer. The mutation appears to disrupt atomic packing at the dimer interface, which induces a change of kinetic mechanism. A single mutation in a region of the protein remote from the active site can thus act as a molecular switch to confer cooperativity on an enzyme.
Visual Pigments in Single Rods and Cones of the Human Retina
Authors: Brown Paul K. , Wald George
Published: October 2006

Difference spectra of the visual pigments have been measured in single rods and cones of a parafoveal region of the human retina. Rods display an absorption maximum (λ
max
) at about 505 mμ, associated with rhodopsin. Three kinds of cones were measured: a blue-sensitive cone with λ
max
about 450 mμ; two green-sensitive cones with λ
max
about 525 mμ; and a red-sensitive cone with λ
max
about 555 mμ. These are presumably samples of the three types of cone responsible for human color vision.
Toxin from
Aspergillus flavus
: Production on Food Materials of a Substance Causing Tremors in Mice
Authors: Wilson Benjamin J. , Wilson Christina H.
Published: October 2006

A strain of
Aspergillus flavus
produces, on foodstuffs, a substance which causes tremors and convulsions when administered to mice and certain other animals. The tremorgen, which differs from other recognized toxins attributed to this species, is associated with a distinct, dark spot on thin-layer chromatograms viewed under ultraviolet light.
Newborn Attention as Affected by Medication during Labor
Authors: Stechler Gerald
Published: October 2006

Babies, 2- to 4-days old, whose mothers received heavy medication during labor were less attentive than those babies whose mothers received light medication.
Pluripotent Stem Cell Function of the Mouse Marrow "Lymphocyte"
Authors: Cudkowicz G. , Bennett M. , Shearer G. M.
Published: October 2006

Bone marrow from normal and polycythemic mice was filtered through glass wool columns to remove cells other than "lymphocytes." For a given number of nucleated cells, filtered marrow was more efficient than the original marrow in repopulating the spleen of an isogenic recipient previously exposed to lethal irradiation. The proliferative capacity of both the filtered and unfiltered marrow suspensions appeared to be a constant function of the number of small and medium "lymphocytes" present and not of any other cell type.
Sterol Induction of Reproduction and Stimulation of Growth of
Pythium
and
Phytophthora
Authors: Hendrix James W.
Published: October 2006

Sterols of fungal, plant, and animal origin induced sexual reproduction in
Pythium periplocum
and
Phytophthora megasperma
var.
sojae
and the formation of large zoosporangia in
Phytophthora parasitica
var.
nicotianae
. Some sterols, especially cholesterol, stimulated growth.
Composition of Basalts from the Mid-Atlantic Ridge
Authors: Engel A. E. J. , Engel Celeste G.
Published: October 2006

Studies of volcanic rocks in dredge hauls from the submerged parts of the Mid-Atlantic Ridge suggest that it consists largely of tholeiitic basalt with low values of K, Ti, and P. In contrast, the volcanic islands which form the elevated caps on the Ridge are built of alkali basalt with high values of Ti, Fe
3+
, P, Na, and K. This distinct correlation between the form of the volcanic structures, elevation above the sea floor, and composition suggests that the islands of alkali basalt are derived from a parent tholeiitic magma by differentiation in shallow reservoirs. The volume of low-potassium tholeiites along the Mid-Atlantic Ridge and elsewhere in the oceans appears to be many times that of the alkali basalts exposed on oceanic islands. Tholeiitic basalts with about 0.2 K
2
O appear to be the primary and predominant magma erupted on the oceanic floor.
Pacemaker Neurons: Effects of Regularly Spaced Synaptic Input
Authors: Perkel Donald H. , Schulman Joseph H. , Bullock Theodore H. , Moore George P. , Segundo José P.
Published: October 2006

The consequences of inhibitory or excitatory synaptic input between pacemaker neurons were predicted mathematically and through digital-computer simulations, and the predicted behavior was found to occur in abdominal ganglia of
Aplysia
and in stretch receptors of
Procambarus
. Discharge patterns under conditions that do not involve interneuronal feedback are characteristic and self-stabilizing. Paradoxically, increased arrival rates of inhibitory input can increase firing rates, and increased excitatory input rates can decrease firing rates.
Femoral Expansion in Aging Women: Implications for Osteoporosis and Fractures
Authors: Smith Richmond W. , Walker Richard R.
Published: October 2006

In femoral radiographs of 2030 aging women, the diameter of the midshaft periosteum increased as cortical thickness declined. Since the cortical area enlarged, periosteal accretion exceeded endosteal resorption. Since the section modulus increased more than did cortical area, the ratio of flexural failure resistance to crush resistance increased, in apparent contrast to the changes observed in the femoral neck.
Replication of DNA and Cell Division in Synchronously Dividing Cultures of
Euglena gracilis
Authors: Edmunds Leland N.
Published: October 2006

Autotrophic
Euglena gracilis
Klebs (strain Z) that are grown axenically on defined, inorganic medium on a regime of 14 hours of light and 10 hours of darkness double their cell number every 24 hours by dividing synchronously during the dark period. The DNA content doubles in a stepwise manner during the last 6 hours of the light period just prior to cell division. This result agrees with those for most higher cells. Although DNA replication is a necessary condition for cell division it is not a sufficient one.
Vestibular Nuclei: Activity of Single Neurons during Natural Sleep and Wakefulness
Authors: Bizzi Emilio , Pompeiano Ottavio , Somogyi Istvan
Published: October 2006

The rate of spontaneous discharge of second-order vestibular neurons is higher during wakefulness than during drowsiness and synchronized sleep. The activity of units recorded from the lateral (and superior) vestibular nucleus remains unmodified or is slightly increased during desynchronized sleep, in spite of the complete disappearance of the postural tonus. Units in medial and descending vestibular nuclei show bursts of rapid discharge associated with the eye movements characteristic of desynchronized sleep.
Macroglobulin from Human Plasma Which Forms an Enzymatically Active Compound with Trypsin
Authors: Mehl John W. , O'Connell William , DeGroot John
Published: October 2006

The protein from human plasma which forms an enzymatically active complex with trypsin and is able to protect trypsin from inhibition by soybean trypsin inhibitor has been shown to be an α
2
-macroglobulin. It was obtained from the lipid-poor euglobulin of Cohn Fraction III-0, and appears to be closely related to the 19
S
-glycoprotein or α
2
-macroglobulin
Thymidine Incorporation by Mitochondria in
Physarum polycephalum
Authors: Guttes Edmund , Guttes Sophie
Published: October 2006

Cytoplasmic particles of the slime-mold,
Physarum polycephalum
, incorporate tritiated thymidine in a form which is insoluble in acid and in ribonuclease, and soluble in deoxyribonuclease. Evidence for the mitochondrial nature of these thymidine-incorporating particles is based on their distribution, size, and staining behavior.
Fluted Projectile Points: Their Age and Dispersion
Authors: Haynes C. Vance
Published: October 2006

The stratigraphic record shows Clovis projectile points to be restricted to sediments between 11,000 and 11,500 years old. Underlying deposits dating back 11,600 to 13,000 years are without evidence of human occupation. In the High Plains, overlying deposits dating back 10,000 to 11,000 years contain Folsom and Hell Gap artifacts and are without mammoth remains. The glacial history of Alaska, Canada, and the Great Lakes region indicates that, for the first time in at least 15,000 years, an ice-free, trans-Canadian corridor opened up approximately 12,000 years ago. Since Clovis points are distributed from coast to coast south of the Valders ice border, the abrupt appearance of Clovis artifacts in the stratigraphic record of the High Plains some 700 years later suggests that Clovis progenitors passed through Canada during Two Creeks time. If eastern fluted points (for example, Enterline) are older than Clovis points, the difference may be on the order of only a hundred or so years, not thousands.

The change from Clovis points to Folsom points in the High Plains may be related to a marked decline in the mammoth population after 11,000 years ago, but whether or not man was a prime factor in the extinction of Pleistocene megafauna is a moot question.

On the basis of new data and critical geological evaluation of dates obtained by the radiocarbon method a hypothesis has been offered to explain (i) the abrupt appearance of Clovis points in the stratigraphic record of the United States around 11,500 years ago, and (ii) the lack of a cultural continuum in the United States leading to fluted projectile points. Llano hunters, like the game they pursued, may have persisted longer in some areas of the continent (for example, Bull Brook) than in others, but if a Clovis site can be found for which good stratigraphic evidence supports a date earlier than the Two Creeks interstade, then correlation of this event to the opening of the trans-Canadian ice-free corridor is incorrect. Such a misinterpretation of timing would not affect the explanation for the lack of Clovis progenitors in the United States. We must continue to look for an indigenous cultural continuum leading to Clovis points, but if such cannot be demonstrated in the conterminous United States, then it would appear that fluted projectile points were developed elsewhere. Clovis progenitors might best be sought in northern Alaska or the Mackenzie Valley.

The interpretations offered here are based on new data and critical geological evaluation of dates previously obtained by the radiocarbon method. How valid these interpretations are can be ascertained only through careful scrutiny of all man-mammoth associations found in the future, to assure precise relating of dates, fossils, and ar tifacts to the stratigraphic framework. We must pay closer attention to stratigraphic detail if we are to make the fullest use of radiocarbon dating.
Map-Based Cloning of a Gene Controlling Omega-3 Fatty Acid Desaturation in
Arabidopsis
Authors: Arondel Vincent , Lemieux Bertrand , Hwang Inhwan , Gibson Sue , Goodman Howard M. , Somerville Chris R.
Published: October 2006

A gene from the flowering plant
Arabidopsis thaliana
that encodes an omega-3 desaturase was cloned on the basis of the genetic map position of a mutation affecting membrane and storage lipid fatty acid composition. Yeast artificial chromosomes covering the genetic locus were identified and used to probe a seed complementary DNA library. A complementary DNA clone for the desaturase was identified and introduced into roots of both wild-type and mutant plants by Ti plasmid-mediated transformation. Transgenic tissues of both mutant and wild-type plants had significantly increased amounts of the fatty acid produced by this desaturase.
Electrolytic Conductance of Sea Water: Effect of Calcium Carbonate Dissolution
Authors: Park Kilho
Published: October 2006

Calcium carbonate dissolution in the presence of excess carbon dioxide increased the specific conductance of sea water by approximately 6 × 10
-5
ohm
-1
cm
-1
per millimole of carbonate dissolved. The observed conductance increase can be explained by the partial equivalent conductance of calcium bicarbonate and by the hindrance effect of uncharged carbon dioxide dissolved in sea water.
Temperature Dependence of the Activity of the Antitumor Factor in the Common Clam
Authors: Hegyeli Andrew
Published: October 2006

The tumor inhibiting action of extracts of the common clam,
Mercenaria mercenarius
, is very low in the winter and can be restored to the high summer values by heat.
Proton Tunneling in Radiation-Induced Mutation
Authors: Rein Robert , Harris Frank E.
Published: October 2006

The equilibrium proton distribution and tunneling rate in the N-H. . . N hydrogen bond of the guanine-cytosine base pair have been calculated quantum mechanically for the ground state, a charge-transfer excited state, and positive and negative ionic states. These results are consistent with the idea that tautomeric rearrangement can be a cause of radiation induced mutation or carcinogenesis.
Attitude Statements as Positive and Negative Reinforcements
Authors: Golightly Carole , Byrne Donn
Published: October 2006

The finding that attraction is a function of attitude similarity has been interpreted as a special case of the effect of positive and negative reinforcements on attraction. A simple discrimination learning task was employed in which the reinforcements were attitude statements similar and dissimilar to the opinions of the subject. The presentation of similar attitude statements after each correct response and dissimilar attitude statements after each incorrect response significantly changed response probability. The hypothesis that such statements could be used as reinforcers in a learning situation was thus confirmed.
Antibody Plaque Formation by Normal Mouse Spleen Cell Cultures Exposed in vitro to RNA from Immune Mice
Authors: Friedman Herman
Published: October 2006

Suspensions of normal spleen cells from nonimmune mice were treated in vitro with RNA extracted from spleen cells from donor mice immunized 4 days previously with sheep erythrocytes. Subsequent incubation of the RNA-treated cells in tissue culture medium at 37° C for several days resulted in a marked increase in the number of localized zones of hemolysis ("antibody plaques") in relation to the number of viable cells plated in agar containing sheep erythrocytes and complement. Nonimmune cells maintained in tissue culture medium did not form plaques after incubation with either RNA from immune mice or ribonuclease-treated RNA from immune mice, or with RNA from nonimmune donor mice, or from donors immunized with chicken erythrocytes or bovine serum albumin.
Neuromimes: Action of a Reciprocally Inhibitory Pair
Authors: Harmon Leon D.
Published: October 2006

Two electronic neuron models (neuromimes) connected to a common excitatory input and having both self- and mutual-inhibition were used to simulate the pulse patterns which control wing musculature in certain insects. With variation of stimulus frequency, firing patterns changed in discrete steps. Pattern change was found to be hysteretic: the pattern elicited by a given stimulus frequency depended on whether that frequency was approached from above or below. Pattern selection could be controlled by the injection or deletion of a single pulse in the stimulus pulse-train as well as by smooth frequency change.
Ancient Copper and Copper-Arsenic Alloy Artifacts: Composition and Metallurgical Implications
Authors: Key C. A.
Published: October 2006

Various copper and copper-arsenic alloy artifacts from the Dead Sea area lack the tin and zinc that are normal trace elements. The trace elements found in the artifacts suggest that a copper sulf-arsenate ore was used in making some of them. The metallurgical use of such ore around 3000 B.C. has not been previously reported.
Reaction Time to Cortical Stimulation
Authors: Miller J. , Glickstein M.
Published: October 2006

A monkey was trained to release a lever when a stimulus was applied to the striate cortex. Reaction times to stimulation of the striate cortex were consistently 30 milliseconds shorter than reaction times to visual stimulation. The technique appears to be fruitful for analysis of neural mechanisms in a simple behavioral task.
Arabidopsis
and
Nicotiana
Anthocyanin Production Activated by Maize Regulators
R
and
C1
Authors: Lloyd Alan M. , Walbot Virginia , Davis Ronald W.
Published: October 2006

Anthocyanin pathway-specific transcriptional activators
R
and
C1
from the monocot maize were expressed in two dicots,
Arabidopsis thaliana
and
Nicotiana tabacum
. Expression of
R
caused augmented anthocyanin pigmentation in both plant species and augmented trichome (hair) production in
Arabidopsis
. Alone,
C1
had no effect. Hybrid transgenic
Arabidopsis
expressing both
C1
and
R
produced anthocyanins in root, petal, and stamen tissues that normally never express anthocyanins. When
R
was expressed in the transparent testa glabrous (without anthocyanins and trichomes) mutant of
Arabidopsis
, the deficiency was complemented and both anthocyanins and trichomes were restored.
Ontogeny of a Salt Marsh Estuary
Authors: Redfield Alfred C.
Published: October 2006

The development of a typical New England salt marsh, and the growth of the sand spit which shelters it, during the past 4000 years has been reconstructed from soundings and borings of the peat. The results have been interpreted with the aid of observations on the structure of the marsh and estimates of the rate of its vertical accretion based on carbon-14 determinations.
Arbovirus Hemagglutinin Inhibitor in Acetone-Extracted Serums from Normal Chickens
Authors: Holden Preston , LaMotte Louis C. , Shriner Ronald B.
Published: October 2006

A highly selective hemagglutinin inhibitor in serums from adult female chickens appears to be activated during extraction of the serum with acetone for removal of the usual lipid inhibitors. The acetone-insoluble inhibitor may be removed by filtration of the serum through Seitz pads. The precursor of the inhibitor in raw serum can be precipitated by two methods of removing euglobulins from solution.
Quartz: Anomalous Weakness of Synthetic Crystals
Authors: Griggs D. T. , Blacic J. D.
Published: October 2006

The strength of a synthetic quartz crystal drops rapidly at 400°C, and at 600°C is a hundredfold lower than at 300°C. Large plastic deformations can be produced without fracture. The predominant mechanism of deformation is translation gliding. The preferred explanation for this anomalous weakness is that this synthetic quartz contains water which has hydrolyzed the silicon-oxygen bonds. The silanol groups so formed are presumed to be rendered sufficiently mobile by elevating the temperature to 400°C so that they align themselves in dislocation lines and move through the crystal with the dislocation under the small applied shear stress.
Chemistry of Isotopes
Authors: Bigeleisen Jacob
Published: October 2006

With the exception of the field of chemical kinetics, a brief survey has been presented of the principles of isotope chemistry and their utility in the ever-unfolding panorama of scientific research. We have come a long way since Soddy and Fajans arrived at the concept of chemical twins—isotopes. There are still places to go.
Preference for Shapes of Intermediate Variability in the Newborn Human
Authors: Hershenson Maurice , Munsinger Harry , Kessen William
Published: October 2006

Newborn humans presented with pairs of shapes, each shape differing in number of turns (angles), prefer shapes with 10 turns to shapes with 5 turns or 20 turns, as inferred from photographic recordings of eye fixations.
Bioelectric Control of Bioluminescence in the Dinoflagellate
Noctiluca
. I. Specific Nature of Triggering Events
Authors: Eckert Roger
Published: October 2006

The flash of
Noctiluca miliaris
occurs only in response to a characteristic all-or-none action potential, the polarity of which is opposite to that of metazoan action potentials, whether recorded internally or externally. Mechanical stimulation evokes a slow, generator-like graded potential which can give rise to the flash-triggering action potential. The flash is all-or-none; it facilitates, summates, and exhibits fatigue, each independently of changes in the amplitude of the action potential.