bluuebunny/crossref_metadata_2025 huggingface dataset:
Strain of Mycoplasma Associated with Human Reproductive Failure
Authors: Kundsin Ruth B. , Driscoll Shirley G. , Ming Pen-ming L.
Published: October 2006

A strain of mycoplasma not previously described has been isolated from the chorion, decidua, and amnion of a patient who sustained a spontaneous abortion during the middle trimester. The fetal membranes exhibited an inflammatory reaction, but no evidence of other infectious agents, bacterial or viral, was noted. The T strain identified is not a classical mycoplasma; it differs in growth and nutritional requirements from the T strains previously characterized.
Biohazards Symbol: Development of a Biological Hazards Warning Signal
Authors: Baldwin Charles L. , Runkle Robert S.
Published: October 2006

The need for a symbol to warn of potential infection hazards became apparent during Public Health Service contract work on the development of containment facilities for virus-leukemia research. A program of direct inquiry and a search of the literature revealed that there was no universally used signal and that scientific and safety organizations concurred in the need for one. Criteria for symbol design were established, and final selection was based on "uniqueness" and "memorability." The National Institutes of Health is recommending use of the symbol as a warning of biological hazard.
Potamotrygon
spp.: Elasmobranchs with Low Urea Content
Authors: Thorson Thomas B. , Cowan C. Michael , Watson Donald E.
Published: October 2006

All previously reported species of Chondrichthyes, from both marine and fresh water, have contained urea at concentrations ranging from about 300 to 1300 milligrams of urea nitrogen per 100 milliliters of fluid. Body fluids from two species of
Potamotrygon
, permanent residents of the Amazon basin, contained only 2 to 3 milligrams of urea nitrogen per 100 milliliters. Although they have abandoned the retention of urea exhibited by other chondrichthyans, the extent to which they have lost the mechanisms of retaining and tolerating urea in a hypertonic medium has not been determined.
Enzyme Induction by Corticosteroids in Embryonic Cells: Steroid Structure and Inductive Effect
Authors: Moscona A. A. , Piddington R.
Published: October 2006

Glutamine synthetase in the developing retina of the chick embryo can be induced to increase by certain corticosteroids. The inductive effectiveness of various natural corticosteroids has been examined in organ cultures of embryonic retina and correlated with specific groupings on the steroid molecules.
Antigenic Competition: Cellular or Humoral
Authors: Radovich Jevrosima , Talmage David W.
Published: October 2006

The injection of one antigen into mice inhibited the response to a second when 1 to 10 days separated the two injections. When the same type of inhibition was attempted in γ-irradiated mice reconstituted with normal spleen cells, the inhibition was greater in mice receiving 50 million spleen cells than in those receiving 10 million. The results are interpreted as favoring a humoral mechanism of inhibition.
Hydraulic Compression of Mice to 166 Atmospheres
Authors: Kylstra J. A. , Nantz R. , Crowe J. , Wagner W. , Saltzman H. A.
Published: October 2006

Hydraulic uniform compression elicited tremors, uncoordinated limb movements, and tonic convulsions in liquid-breathing mice at pressures ranging from 50 to 100 atmospheres. Such abnormal muscular activity was observed neither in control animals nor in mice caudally to a spinal transection. Uniform compression of isolated preparations of mouse muscle in saline failed to contract at pressures up to 200 atmospheres.
The Future of Scientific Journals
Authors: Brown W. S. , Pierce J. R. , Traub J. F.
Published: October 2006

Since many of the problems that beset readers, authors, and publishers of scientific journals are caused by the growth of science or by the frailties of human nature, we cannot hope for complete solutions. In an effort to make progress, within the framework of the possible, we propose that journals stop binding papers into issues and, instead, distribute to each subscriber a personalized stream of papers, abstracts, and titles. This type of distribution, which has been made possible by the advent of high-speed computers, would not affect the traditional roles of editors, referees, and libraries. We also propose that journals recognize the need for very rapid communication in certain fields, and meet the threat of public preprint-exchange systems in these fields by themselves publishing preprints in an appropriately limited manner.
Bronchiolar and Large Alveolar Cell in Pulmonary Phospholipid Metabolism
Authors: Niden Albert H.
Published: October 2006

The nonciliated bronchiolar cells (Clara cells) lining the terminal airways actively secrete a phospholipid. In contrast, the large alveolar epithelial cells (type II, granular pneumonocyte) are active phagocytic cells. It is proposed that the Clara cell is the main source of pulmonary phospholipid production (presumably surfactant) while the large alveolar cell is responsible for its subsequent breakdown.
Successiveness Discrimination as a Two-State, Quantal Process
Authors: Kristofferson Alfred B.
Published: October 2006

The duration of the "psychophysical time quantum" measured through the application of a two-state model of successiveness discrimination is equal in magnitude to the modal zero-crossing interval of the alpha rhythm. The two quantities have similar distributions and they are correlated over individuals.
Direction of Chain Growth in Polysaccharide Synthesis
Authors: Robbins P. W. , Bray D. , Dankert M. , Wright A.
Published: October 2006

The biosynthesis of a bacterial polysaccharide—the surface O-antigen of
Salmonella newington
—differs in several respects from the more classical example of glycogen synthesis. Sugars are not transferred directly to the antigen from sugar nucleotide precursors but are transferred first into lipid-linked oligosaccharides. Growth of the polysaccharide chain then occurs by assembly of these lipid-linked precursors at the reducing end of the polymer rather than at its nonreducing end as in glycogen. This method of assembly, in which nascent chains are transferred to the next subunit, is analogous to the growth of proteins or fatty acids. It seems possible that these differences reflect the more complex requirements of a surface polysaccharide synthesized by membrane-bound enzymes. If this is the case, then several other polysaccharide systems may be synthesized by comparable mechanisms.
Solar Oblateness and Fluid Spin-Down
Authors: McDonald B. E. , Dicke R. H.
Published: October 2006

An experiment performed on a differentially rotating, density-stratified fluid shows that "spin-down" need not occur under the condition of stratification. Inasmuch as density stratification occurs in the interior of the sun, spin-down probably does not exist in the solar interior, and the observed solar oblateness may indicate that the sun contains a rapidly spinning core.
Olfactory Input to the Hypothalamus: Electrophysiological Evidence
Authors: Scott John W. , Pfaffmann Carl
Published: October 2006

Electrical stimulation of the rat's olfactory bulb or lateral olfactory tract elicited unit discharges in the region of the medial forebrain bundle of the lateral hypothalamus, with latencies of 4 to 25 milliseconds. Unit responses in this area were driven by odors in preparations that were paralyzed to prevent breathing artifacts.
Ultraviolet Emissions Observed near Venus from Mariner V
Authors: Barth Charles A. , Pearce Jeffrey B. , Kelly Kenneth K. , Wallace Lloyd , Fastie William G.
Published: October 2006

A Lyman-alpha airglow of atomic hydrogen measured in the outer atmosphere of Venus showed that atomic hydrogen is present. The variation as a function of height indicates that the temperature of the upper atmosphere of Venus is lower than that of Earth. An ultraviolet airglow of atomic oxygen was not found. An ultraviolet nightglow was observed on the dark limb.
Expression of the
Escherichia coli
Cell Division Gene
sep
Cloned in a λ Charon Phage
Authors: Irwin Carleen A. , Fletcher Gail , Sills Cynthia L. , Walker James R.
Published: October 2006

The
Escherichia coli
cell division gene
sep
, which probably codes for one of the penicillin-binding proteins, has been cloned into λCharon 10 to form a viable
sep
+
transducing phage. After infection with this hybrid phage, penicillin-binding protein 3 was overproduced and incorporated into the
E. coli
inner membrane.
Synaptotagmin: a Calcium Sensor on the Synaptic Vesicle Surface
Authors: Brose Nils , Petrenko Alexander G. , Südhof Thomas C. , Jahn Reinhard
Published: October 2006

Neurons release neurotransmitters by calcium-dependent exocytosis of synaptic vesicles. However, the molecular steps transducing the calcium signal into membrane fusion are still an enigma. It is reported here that synaptotagmin, a highly conserved synaptic vesicle protein, binds calcium at physiological concentrations in a complex with negatively charged phospholipids. This binding is specific for calcium and involves the cytoplasmic domain of synaptotagmin. Calcium binding is dependent on the intact oligomeric structure of synaptotagmin (it is abolished by proteclytic cleavage at a single site). These results suggest that synaptotagmin acts as a cooperative calcium receptor in exocytosis.
Site-Specific Modification of Pre-mRNA: the 2′-Hydroxyl Groups at the Splice Sites
Authors: Moore Melissa J. , Sharp Phillip A.
Published: October 2006

A simple and efficient method for synthesizing long, site-specifically modified RNA molecules was developed whereby segments of RNA were joined with the use of bacteriophage T4 DNA ligase. A single hydrogen or
O
-methyl group was substituted for the 2′-hydroxyl group at either splice site of a nuclear pre-messenger RNA substrate. Splicing of the modified pre-messenger RNA's in vitro revealed that, although a 2′-hydroxyl is not absolutely required at either splice site, the 2′-hydroxyl at the 3′ splice site is important for the second step of splicing. These results are compared to previous studies of analogous 2′-hydroxyl groups in the self-splicing
Tetrahymena
group I intron.
Coronary Disease in Spawning Steelhead Trout
Salmo gairdnerii
Authors: Van Citters Robert L. , Watson Nolan W.
Published: October 2006

Coronary degeneration was absent in young trout taken in fresh water and rare in immature fish at sea, but the incidence and severity were sharply greater in migrating fish and almost uniformly present in spawning fish. Several fish taken after they had reentered salt water after spawning had no lesions; lesions in fish taken during their second spawning migration were not cumulative. These facts suggest that the process is reversible.
Sulfate Reduction in Soil: Effects of Redox Potential and
p
H
Authors: Connell W. E. , Patrick W. H.
Published: October 2006

Reduction of sulfate to sulfide in waterlogged soils was dependent on soil redox potential and pH. Little or no sulfide accumulated with a redox potential above -150 millivolts, or with a
p
H outside the range 6.5 to 8.5.
Auditory Sense in Certain Sphingid Moths
Authors: Roeder Kenneth D. , Treat Asher E. , Vandeberg Jerry S.
Published: October 2006

Moths of the genus
Celerio
, hovering and feeding from blossoms, have been observed to react vigorously to high-pitched sounds. The acoustic receptor appears to involve the labial palps. Its characteristics have been determined from responses made, when the moth is exposed to artificial sound pulses, by an interneuron originating in its head. These responses have been found only in 4 out of 19 sphingid species tested.
Are "Infinity Machines" Paradoxical?
Authors: Grünbaum Adolf
Published: October 2006

The mathematical physicist Hermann Weyl (2) has claimed that, unless machines can accomplish an
infinite
sequence of distinct operations in a
finite
time, the standard mathematical theory of motion is beset by one of Zeno's kinematical paradoxes. Hence I have compared the kinematics of several such "infinity machines" to the kinematics of the continuous motion of Achilles. And I have argued that, while some designs for infinity machines are indeed inconsistent, others are not impossible on purely kinematical grounds. This argument was coupled with several reasons for denying Zeno's and A. N. Whitehead's allegation of paradox against the mathematical, description of the motion of Achilles.
Genetic Selection for Voluntary Alcohol Consumption in the Albino Rat
Authors: Eriksson Kalervo
Published: October 2006

By outbreeding Wistar rats and selecting for breeding animals that differ in their alcohol consumption, we have raised two genetically different lines. Marked differences between the sexes and the strains were evident by the eighth generation. Selection is reflected in the regression coefficient .754, which accounts for 65.9 percent of the variance. The heritabilities differ significantly in the two sexes,
h
2
for the males being .263, and for the females .371; this difference seems mainly ascribable to sex-linkage of some of the genetic factors controlling voluntary consumption of alcohol.
Hydrogen Embrittlement of Metals
Authors: Rogers H. C.
Published: October 2006

Hydrogen interacts with many metals to reduce their ductility (
2
) and frequently their strength also. It enters metals in the atomic form, diffusing very rapidly even at normal temperatures. During melting and fabrication, as well as during use, there are various ways in which metals come in contact with hydrogen and absorb it. The absorbed hydrogen may react irreversibly with oxides or carbides in some metals to produce a permanently degraded structure. It may also recombine at internal surfaces of defects of various types to form gaseous molecular hydrogen under pressures sufficiently high to form metal blisters when the recombination occurs near the outer surface. In other metals, brittle hydrides that lower the mechanical properties of the metal are formed. Another type of embrittlement is reversible, depending on the presence of hydrogen in the metal lattice during deformation for its occurrence. Under some conditions the failure may be delayed for long periods. A number of different mechanisms have been postulated to explain reversible embrittlement. According to some theories hydrogen interferes with the processes of plastic deformation in metals, while according to others it enhances the tendency for cracking.
Modification of Motivated Behavior Elicited by Electrical Stimulation of the Hypothalamus
Authors: Valenstein Elliot S. , Cox Verne C. , Kakolewski Jan W.
Published: October 2006

Previous reports demonstrated that hypothalamic stimulation may elicit either eating, drinking, or gnawing and emphasized both the specificity of the neural circuits mediating these behaviors and the similarity to behavior during natural-drive states such as hunger and thirst. We find that, after a period of very consistent elicitation of one of these behaviors, the animal may exhibit an equally consistent alternate behavior. A learning component is implicated in the association of hypothalamic stimulation with a particular behavior pattern.
Pathogenesis of a Local Graft versus Host Reaction: Immunogenicity of Circulating Host Leukocytes
Authors: Elkins William L. , Guttmann Ronald D.
Published: October 2006

A local invasive-destructive reaction typical of that seen in allograft rejection occurs when Lewis rat spleen cells are inoculated under the capsule of Lewis kidney freshly grafted into F
1
hybrid hosts. Thus the donor lymphoid cells can be immunogenically stimulated by circulating host leukocytes and the interaction of these two cell populations results in nonspecific damage to kidney parenchyma. The results indicate that passenger leukocytes in organ allografts may be important immunogenic agents.
Desalination by Osmosis-Reverse Osmosis Couple
Authors: Popper Karel , Merson Richard L. , Camirand Wayne M.
Published: October 2006

Water is separated from brines by a semipermeable membrane. Water flows by osmosis across the membrane into a sealed chamber where it creates pressure. This pressure is transmitted by a water-immiscible liquid piston to a second chamber where it effects reverse osmosis. Water-removal rates are calculated.
Identification of a Prenylation Site in Delta Virus Large Antigen
Authors: Glenn Jeffrey S. , Watson John A. , Havel Christopher M. , White Judith M.
Published: October 2006

During replication, hepatitis delta virus (HDV) switches from production of small to large delta antigen. Both antigen isoforms have an HDV genome binding domain and are packaged into hepatitis B virus (HBV)-derived envelopes but differ at their carboxyl termini. The large antigen was shown to contain a terminal CXXX box and undergo prenylation. The large, but not the small, antigen formed secreted particles when expressed singly with HBV surface antigen. Mutation of Cys211in the CXXX box of the large antigen abolished both prenylation and particle formation, suggesting that this site is important for virion morphogenesis.
Ciguatoxin: More Than an Anticholinesterase
Authors: Rayner Martin D. , Kosaki Thomas I. , Fellmeth Enid L.
Published: October 2006

Anticholinesterase action of ciguatoxin has been reported. A study of the pharmacology of the action of the toxin on the respiratory system suggests that additional properties may be involved in the respiratory failure—the usual cause of death in ciguatera poisoning.
Nerves in Cortical Bone
Authors: Cooper Reginald R.
Published: October 2006

Modified electron-microscopic techniques permit the sectioning of fully mineralized compact bone. Cortical canals in human femur are extensively innervated. Most nerves are unmyelinated and range from 0.5 to 10 micrometers in diameter. I have found a few mixed nerves (myelinated and unmyelinated fibers), one of which was 130 micrometers in diameter.
Flea
Ctenophthalmus
: Heterogeneous Hexagonally Organized Layer in the Midgut
Authors: Richards A. Glenn , Richards Patricia A.
Published: October 2006

The ventriculus or midgut of adult fleas of the genus
Ctenophthalmus
(Hystricopsyllidae) is surrounded by a complex investment consisting of a "beaded layer," circumferential and longitudinal muscles, minute fibrils of the sort commonly called collagenous, and a granular layer at the boundary of the hemocoel. The beaded layer is remarkable in consisting of two types of short cylinders of greatly different diameters, each type arranged in a mixed hexagonal array.
Cigarette Smoking: Stimulatory Effect on Metabolism of 3,4-Benzpyrene by Enzymes in Human Placenta
Authors: Welch R. M. , Harrison Y. E. , Conney A. H. , Poppers P. J. , Finster M.
Published: October 2006

The enzymatic hydroxylation of 3,4-benzpyrene was not detected in human placentas obtained after childbirth from nonsmokers, whereas this enzyme activity was present in placentas obtained from individuals who smoked cigarettes. The degree of induction of benzpyrene hydroxylase caused by cigarette smoking varied in different individuals. Treatment of pregnant rats with benzpyrene increased the activity of this hydroxylase in the placenta.
Memory Impairment after Subcutaneous Injection of Acetoxycycloheximide
Authors: Barondes Samuel H. , Cohen Harry D.
Published: October 2006

Subcutaneous injection of 240 micrograms of acetoxycycloheximide in mice rapidly produces marked inhibition of cerebral protein synthesis. Treated mice were trained to escape shock by choosing the lighted limb of a T-maze. When trained five or more minutes after injection, they had a normal capacity to learn. They remembered normally 3 hours after training, but 6 hours after training they had markedly impaired retention. Amnesia persisted thereafter. Injections immediately after training had a less marked but significant amnesic effect. These studies suggest that protein synthesis is not necessary for learning or for memory for 3 hours after training but that it is required for long-term memory. The protein synthesis which appears to be necessary for long-term memory occurs during training, or within minutes after training, or both.
Cupulae in Shark Neuromasts: Composition, Origin, Generation
Authors: Tester Albert L. , Kendall James I.
Published: October 2006

Cupulae on the surface of the sensory epithelium of canal neuromasts of the shark lateralis system have been demonstrated. They are mounds of mucoid material secreted primarily by the supporting cells of the neuromast epithelium. Individual columns of mucus in fixed, stained sections produce striations perpendicular to the neuromast surface. The hair of the sensory cell is embedded in mucus at the bases of coalescing columns produced by a group of surrounding supporting cells. There is evidence that mucus production is continuous and is accompanied by regeneration of secretory cells and elimination of necrotic cells at the distal surface. It follows that cupular material is being discarded either intermittantly or continually, along with trapped cell debris and other detritus.
Fossil Alpha-Recoil Analysis of Certain Variant Radioactive Halos
Authors: Gentry Robert V.
Published: October 2006

The distribution of alpha-radioactivity in the vicinity of uranium and of certain variant radioactive halos in biotite was investigated by the fossil alpharecoil method. Within the limits of the method I could not confirm a previously proposed hydrothermal mechanism for the origin of certain variant halo types due to polonium isotopes.
Maintenance of Responding under a Fixed-Interval Schedule of Electric Shock-Presentation
Authors: McKearney James W.
Published: October 2006

Squirrel monkeys trained to respond under a schedule in which each response postponed the delivery of electric shock developed a steady rate of responding. When a schedule in which an electric shock was presented following the first response occurring after 10 minutes (10-minute fixed-interval schedule) was programed concurrently, there was little effect on the pattern of responding. When the shock-postponement schedule was eliminated, the fixed-interval schedule of shock-presentation maintained a pattern of positively accelerated responding that is characteristic of fixed-interval schedules of reinforcement.
Hereditary Autoimmune Thyroiditis in the Fowl
Authors: Cole R. K. , Kite Joseph H. , Witebsky Ernest
Published: October 2006

In the Cornell C strain of White Leghorn chickens, thyroiditis appeared spontaneously. It was characterized by phenotypic changes due to a decrease of thyroxine, histological damage to the thyroid gland, and the presence in the serum of antibodies to thyroglobulin. Susceptibility to the disease is genetically inherited. Hormonal bursectomy (androgen given to the embryo) suppresses the development of thyroiditis.
Eye Tracking of Observer-Generated Target Movements
Authors: Steinbach Martin J. , Held Richard
Published: October 2006

When an observer moves his arm he shows more precise visual tracking of a target mounted on his fingertip—the eye lags behind the target less and makes fewer corrective saccades—than when he relaxes his arm and the experimenter moves it in a similar manner. Apparently the control system for eye movements can use outflow (efferent) signals in order to anticipate motion of the self-moved target.
Chemosensory Input and Taste Discrimination in the Blowfly
Authors: Dethier V. G.
Published: October 2006

Simultaneous recording of behavioral responses and action potentials from single chemoreceptors in the proboscis of intact blowflies revealed that acceptance of a solution can be mediated either by input from one water receptor or from one salt receptor. Rejection of higher concentrations of salt is mediated by the same salt receptor. A difference of three impulses in the first 100 milliseconds of activity can determine whether the fly accepts or rejects the solution.
Microspectrophotometry of Photoreceptor Organelles from Eyes of the Prawn
Palaemonetes
Authors: Goldsmith Timothy H. , Dizon Andrew E. , Fernandez Hector R.
Published: October 2006

Microspectrophotometric measurements of individual dark-adapted rhabdoms of the prawn
Palaemonetes vulgaris
reveal the presence of two light-sensitive pigments. A pigment with maximum absorbancy at 555 nanometers is converted by light to a long-lived intermediate with wavelength of maximum absorbancy at 496 nanometers. A second pigment with wavelength of maximum absorbancy at 496 nanometers bleaches in the light, seemingly without forming detectable products at wavelengths longer than 375 nanometers. Both pigments occur in each layer of microvilli.
Shell Porosity of Recent Planktonic Foraminifera as a Climatic Index
Authors: Bé Allan W. H.
Published: October 2006

Despite variations in pore diameter and pore concentration between 22 species of planktonic Foraminifera, shell porosites are relatively uniform for those co-occurring in the same latitudinal belts: over 10 percent for tropicalsubtropical species; 5 to 10 percent for temperate species; and less than 5 percent for subpolar-polar species. Shell porosities of fossil planktonic Foraminifera may be useful indices for interpreting Cenozoic climates.
Liver Adenine Nucleotides: Fructose-Induced Depletion and Its Effect on Protein Synthesis
Authors: Mäenpää Pekka H. , Raivio Kari O. , Kekomäki Martti P.
Published: October 2006

Intravenous administration of D-fructose to rats rapidly depletes liver adenosine triphosphate and inorganic phosphate; marked elevations of uric acid and allantoin in plasma follow. Concomitantly the incorporation of DL-leucine-1-
14
C into liver protein is almost completely inhibited.
Plasmodium falciparum
: Phagocytosis by Polymorphonuclear Leukocytes
Authors: Trubowitz S. , Masek B.
Published: October 2006

In vitro, the human polymorphonuclear leukocyte can recognize and ingest the free forms of
Plasmodium falciparum
. Digestive vacuoles form about the engulfed organisms. Neither the polymorphonuclear leukocyte nor the monocyte can recognize the parasitized red cell. Phagocytosis of normal or parasitized red cells was not observed.
Conductance Changes Associated with Receptor Potential in
Limulus
Photoreceptors
Authors: Smith T. G. , Stell W. K. , Brown J. E.
Published: October 2006

The receptor potential in
Limulus
photoreceptors appears to be a consequence not of permeability changes in the cell membrane but of alterations in a light-sensitive constant-current generator.
Noncycling Tumor Cells: Mitogenic Response to Antilymphocytic Serum
Authors: DeCosse Jerome J. , Gelfant Seymour
Published: October 2006

After continuous labeling with tritiated thymidine for a period several times the cell generation time, some ELD ascites cells remained unlabeled. Despite continued exposure to tritiated thymidine, unlabeled mitoses appeared promptly after administration of mouse antilymphocytic serum. Immunosuppression released some noncycling G
2
tumor cells into mitosis.
Nonspecific Staining: Its Control in Immunofluorescence Examination of Soil
Authors: Bohlool B. B. , Schmidt E. L.
Published: October 2006

Gelatin preparations were used to treat soil slides prior to addition of fluorescent antibody. Nonspecific staining was avoided, with no detectable interference to specific staining. Gelatin-rhodamine conjugates served to counterstain as well as to prevent nonspecific staining.
Visual Cortex Neurons: Response to Stimuli during Rapid Eye Movements
Authors: Wurtz Robert H.
Published: October 2006

While awake, unanesthetized monkeys held their eyes stationary, a motionless or slowly moving stimulus falling on the receptive field of striate cortex neurons produced an excitatory response. When a rapid eye movement was made across the same stimulus, many of these neurons continued to give an excitatory response. But the discharge of other neurons was unchanged or was suppressed during the eye movement.
Genetics of Diego Blood Groups in Guatemalan Indians: Use of Antiserums to Diego a and Diego b Antigens
Authors: Cann Howard M. , Van West Betty , Barnett Clifford R.
Published: October 2006

Red blood cells of 255 inhabitants of San Antonio Palopó, an Indian community on the eastern shore of Lake Atitlán, Guatemala, have been typed with antiserum to Diego a (Di
a
) and the newly discovered antiserum to Di
b
. Individuals with erythrocyte antigenic types Di(a+b-, Di(a+b+), and Di(a-b+) have been found, but the type Di(a-b-) has not been encountered. Population frequencies of antigenic types and family studies support the hypothesis that the erythrocyte antigens, Di
a
and Di
b
, are controlled by two codominant alleles at a single autosomal locus.
Reactions of Aromatic and Sulfur Amino Acids in Ribonuclease with Hydrogen Atoms in Water Solution
Authors: Shapira Raymond , Stein Gabriel
Published: October 2006

Neutral hydrogen atoms are simple, one-electron-equivalent reagents and their reactions are of fundamental interest for chemical kinetics. Functional correlation between aromatic and divalent-sulfur amino acids in ribonuclease is shown in the reaction of ribonuclease with hydrogen atoms in aqueous solution. Products of the reaction are partially characterized.
Harpin, Elicitor of the Hypersensitive Response Produced by the Plant Pathogen
Erwinia amylovora
Authors: Wei Zhong-Min , Laby Ron J. , Zumoff Cathy H. , Bauer David W. , He Sheng Yang , Collmer Alan , Beer Steven V.
Published: October 2006

A proteinaceous elicitor of the plant defense reaction known as the hypersensitive response was isolated from
Erwinia amylovora
, the bacterium that causes fire blight of pear, apple, and other rosaceous plants. The elicitor, named harpin, is an acidic, heat-stable, cell-envelope-associated protein with an apparent molecular weight of 44 kilodaltons. Harpin caused tobacco leaf lamina to collapse and caused an increase in the pH of bathing solutions of suspension-cultured tobacco cells. The gene encoding harpin (
hrpN
) was located in the 40-kilobase
hrp
gene cluster of
E. amylovora
, sequenced, and mutated with Tn
5
tac1. The
hrpN
mutants were not pathogenic to pear, did not elicit the hypersensitive response, and did not produce harpin.
Facilitation of Brain Self-Stimulation by Central Administration of Norepinephrine
Authors: Wise C. David , Stein Larry
Published: October 2006

Rats with electrodes implanted in the medial forebrain bundle stimulated their own brains at sharply reduced rates after systemic administration of disulfiram or intraventricular administration of diethyldithiocarbamate. Both drugs inhibit dopamine-β-hydroxylase, the enzyme responsible for the final step in the biosynthesis of norepinephrine. The suppressed behavior was reinstated by intraventricular injections ofl-norepinephrine, but not by injection of its biologically inactive isomer,d-norepinephrine. Intraventricular administration of dopamine and serotonin did not restore self-stimulation. The rewarding effect of medial forebrain bundle stimulation may depend on the availability of norepinephrine as a transmitter, but not on dopamine or serotonin.
Size Discrimination on the Skin
Authors: Vierck Charles J. , Jones Marshall B.
Published: October 2006

Reasons are given for rejecting the two-point threshold as the standard measure of spatiotactile resolution. As alternative techniques, thresholds were obtained for disc-size and disc-annulus discriminations. Disc-annulus thresholds are comparable to two-point values, but disc-size thresholds are smaller by a factor of 10. Thus, at least part of the cutaneous system is better organized for localization and sizing of a stimulus than for detection of discontinuities in it.
Synaptic Activation of an Electrogenic Sodium Pump
Authors: Pinsker Harold , Kandel Eric R.
Published: October 2006

An identified molluscan interneuron mediates different cholinergic synaptic actions by increasing the conductance of its follower cells to different ions. We have now found that this interneuron also mediates a new class of synaptic actions which does not involve a conductance change but the activation of an electrogenic sodium pump. This synaptic action results in a prolonged inhibitory synaptic potential which is dependent on metabolism and is selectively blocked by cooling and ouabain. In cells which have this synaptic potential, part of the resting membrane potential is also maintained by an electrogenic sodium pump. The same transmitter, acetylcholine, can independently stimulate both a chloride ion conductance and a sodium pump mechanism in the same follower cell by acting on two different postsynaptic receptors.
Magnetoferritin: in Vitro Synthesis of a Novel Magnetic Protein
Authors: Meldrum Fiona C. , Heywood Brigid R. , Mann Stephen
Published: October 2006

The iron storage protein ferritin consists of a spherical polypeptide shell (apoferritin) surrounding a 6-nanometer inorganic core of the hydrated iron oxide ferrihydrite (5Fe
2
O
3
⋅9H
2
O). Previous studies have shown that the in vitro reconstitution of apoferritin yields mineral cores essentially identical to those of the native proteins. A magnetic mineral was synthesized within the nanodimensional cavity of horse spleen ferritin by the use of controlled reconstitution conditions. Transmission electron microscopy and electron diffraction analysis indicate that the entrapped mineral particles are discrete 6-nanometer spherical single crystals of the ferrimagnetic iron oxide magnetite (Fe
3
O
4
). The resulting magnetic protein, "magnetoferritin," could have uses in biomedical imaging, cell labeling, and separation procedures.
Planar Induction of Anteroposterior Pattern in the Developing Central Nervous System of
Xenopus laevis
Authors: Doniach Tabitha , Phillips Carey R. , Gerhart John C.
Published: October 2006

It has long been thought that anteroposterior (A-P) pattern in the vertebrate central nervous system is induced in the embryo's dorsal ectoderm exclusively by signals passing vertically from underlying, patterned dorsal mesoderm. Explants from early gastrulae of the frog
Xenopus laevis
were prepared in which vertical contact between dorsal ectoderm and mesoderm was prevented but planar contact was maintained. In these, four position-specific neural markers (
engrailed-2
,
Krox-20
,
XlHbox 1
, and
XlHbox 6
) were expressed in the ectoderm in the same A-P order as in the embryo. Thus, planar signals alone, following a path available in the normal embryo, can induce A-P neural pattern.
Retrograde Amnesia in Free Recall
Authors: Tulving Endel
Published: October 2006

Supervention of high-priority events in a series of events constituting a free-recall task interferes with postexposure processing of mnemonic information about immediately preceding events, with the result that recall of these preceding events is impaired. Recall of immediately following events is not affected. This retrograde interference is time dependent.
Fauna of Çatal Hüyük: Evidence for Early Cattle Domestication in Anatolia
Authors: Perkins Dexter
Published: October 2006

Analysis of the remains of cattle from Çatal Hüyük indicates that cattle were domesticated in Anatolia by 5800 B.C., and strongly suggests that they were probably domestic at least 500 years earlier. This is the earliest known evidence for the domestication of cattle in the Near East.
Complementation Analysis on Virus-Fused Chinese Hamster Cells with Nutritional Markers
Authors: Kao Fa-Ten , Johnson Robert T. , Puck Theodore T.
Published: October 2006

Cell fusion experiments have been carried out with Chinese hamster cell mutants with different nutritional growth requirements. Conditions have been devised in which approximately 1 to 2 percent of the cell population remaining after fusion are fused, hybrid cells. The all-or-none nature of the genetic markers employed and the extremely low reversion rates insure that no contamination of the hybrid population with parental forms occurs. Hybrids between glycine- and hypoxanthine-requiring mutants are prototrophic, which indicates that both mutations are recessive. Hybrids between a glycine-deficient mutant and a single-step mutant which requires glycine, hypoxanthine, and thymidine are relieved of the glycine dependency, an indication that the two loci associated with glycine dependence are different. This mutation to the triple-supplement requirement as well as a proline deficiency were also shown to be recessive mutations. The system appears applicable to a variety of genetic problems.
Tricyclic Antidepressants: Evidence for an Intraneuronal Site of Action
Authors: Reid W. D. , Stefano F. J. E. , Kurzepa S. , Brodie B. B.
Published: October 2006

Desipramine, a tricyclic antidepressant drug, almost completely prevents the accumulation of tritiated norepinephrine by sympathetic neurons of the rat heart after the injection of a tracer dose of the labeled amine. However, desipramine does not alter the accumulation of norepinephrine after the injection of a large dose of the neurohormone. Despite the failure of desipramine to block the neuronal uptake of norepinephrine, it still prevents exogenous norepinephrine from displacing the endogenous neurohormone (previously labeled with H3-norepinephrine) from intraneuronal storage sites.
Glucose-6-Phosphate Dehydrogenase Deficient Red Cells: Resistance to Infection by Malarial Parasites
Authors: Luzzatto Lucio , Usanga Essien A. , Reddy Shunmugam
Published: October 2006

Erythrocyte mosaicism occurs in females heterozygous for glucose-6-phosphate dehydrogenase deficiency. In blood from female children with acute
Plasmodium falciparum
malaria the parasite rate was 2 to 80 times higher in normal than in deficient erythrocytes. This may be the mechanism whereby the gene for glucose-6-phosphate dehydrogenase deficiency confers selective advantage against malaria to heterozygous females, and thus may have attained the polymorphic frequency occurring in populations living in areas with endemic malaria.
Microvolt Electric Signals from Fishes and the Environment
Authors: Barham E. G. , Huckabay W. B. , Gowdy R. , Burns B.
Published: October 2006

Pulses in the 0.01 to 40 microvolt range, probably generated by white fiber muscle action potentials, were remotely received through dipole antennae from five fishes and one amphibian in aquarium tests. In natural environments, however, no biologically generated signals have been detected. Received instead were a multitude of similar signals originating from unknown sources. The dominant types of these "atmospheric" signals and their reception rates change diurnally and can easily be confused with the fish-generated signals.
Radiocarbon Dating of Petroleum-Impregnated Bone from Tar Pits at Rancho La Brea, California
Authors: Ho T. Y. , Marcus Leslie F. , Berger Rainer
Published: October 2006

A liquid-chromatography method has been developed for the separation of amino acids with the same specific activity in radiocarbon from bones impregnated with isotopically dead petroleum compounds found in the La Brea tar pits. This technique permits the application of radiocarbon dating to such bone assemblages.
Fatty Alcohols (Normal and Isoprenoid) in Sediments
Authors: Sever Judy , Parker P. L.
Published: October 2006

Normal long-chain alcohols were isolated from Recent marine sediments from several environments. The isoprenoid alcohol dihydrophytol, which is thought to originate from phytol, the side chain of chlorophyll, by hydrogenation in the reducing environment of the sediment, was also present in most of the samples. Both the normal and isoprenoid alcohols were found in the Green River shale (Eocene). Geochemical implications are considered.
Taste Nerve Fibers: A Random Distribution of Sensitivities to Four Tastes
Authors: Frank M. , Pfaffmann C.
Published: October 2006

The numbers of rat glossopharyngeal and chorda tympani fibers responding to one, two, three, or four taste stimuli of different quality (sodium chloride, hydrochloric acid, quinine, and sucrose) and to each of the six possible pairs of these stimuli can be predicted if there are four independent sensitivities randomly distributed among innervating fibers.
Requirement of Heparan Sulfate for bFGF-Mediated Fibroblast Growth and Myoblast Differentiation
Authors: Rapraeger Alan C. , Krufka Alison , Olwin Bradley B.
Published: October 2006

Basic fibroblast growth factor (bFGF) binds to heparan sulfate proteoglycans at the cell surface and to receptors with tyrosine kinase activity. Prevention of binding between cell surface heparan sulfate and bFGF (i) substantially reduces binding of fibroblast growth factor to its cell-surface receptors, (ii) blocks the ability of bFGF to support the growth of Swiss 3T3 fibroblasts, and (iii) induces terminal differentiation of MM14 skeletal muscle cells, which is normally repressed by fibroblast growth factor. These results indicate that cell surface heparan sulfate is directly involved in bFGF cell signaling.
Biochemistry at 100°C: Explosive Secretory Discharge of Bombardier Beetles (
Brachinus
)
Authors: Aneshansley Daniel J. , Eisner Thomas , Widom Joanne M. , Widom Benjamin
Published: October 2006

The defensive chemical spray of bombardier beetles is ejected at 100°C, with a heat content of about 0.2 calorie per milligram.
Etching Fission Tracks in Zircons
Authors: Naeser C. W.
Published: October 2006

A new technique has been developed whereby fission tracks can be etched in zircon with a solution of sodium hydroxide at 220°C. Etching time varied between 15 minutes and 5 hours. Colored zircon required less etching time than the colorless varieties.
Cyclic Adenosine Monophosphate: Possible Mediator for Norepinephrine Effects on Cerebellar Purkinje Cells
Authors: Siggins George R. , Hoffer Barry J. , Bloom Floyd E.
Published: October 2006

Microelectrophoretic application of norepinephrine or cyclic adenosine monophosphate reduces the discharge frequency of Purkinje cells in the rat cerebellum. In contrast, other nucleotides accelerate the discharge rate of most units. Parenterally administered theophylline, which inhibits the hydrolysis of cyclic adenosine monophosphate enhances the effects of norepinephrine and cyclic adenosine monophosphate. Therefore, norepinephrine may be able to regulate Purkinje cells functionally by metabolic stimulation of cyclic adenosine monophosphate synthesis.
Ant Alarm Pheromone Activity: Correlation with Molecular Shape by Scanning Computer
Authors: Amoore John E. , Palmieri Guido , Wanke Enzo , Blum Murray S.
Published: October 2006

The ant
Iridomyrmex pruinosus
utilizes 2-heptanone as an alarm pheromone. The activities of 49 ketones and 35 nonketones as alarm pheromones for this species were determined. The molecular shapes of these compounds were assessed by submitting silhouette photographs of their molecular models to a pattern recognition machine. A highly significant correlation exists between molecular shape and alarm activity.
Ozone: Depression of Frond Multiplication and Floral Production in Duckweed
Authors: Feder William A. , Sullivan Florence
Published: October 2006

Plants of
Lemna perpusilla
#6746 grown in an environment charged daily with a low concentration of ozone over 2 weeks were slower to begin multiplying, had a significantly lower rate of frond doubling, and required longer to produce fewer flowers than control plants. Treated plants produced smaller, slightly yellow fronds but had no symptoms of acute injury. Control plants produced four times as many fronds and six times as many flowers as plants continuously exposed to ozone (0.1 part per million).
Toxin from Skin of Frogs of the Genus
Atelopus
: Differentiation from Dendrobatid Toxins
Authors: Fuhrman Frederick A. , Fuhrman Geraldine J. , Mosher Harry S.
Published: October 2006

A potent, dialyzable toxin (atelopidtoxin) occurs in the skin of frogs of the genus
Atelopus
. A concentrate of atelopidtoxin from
Atelopus zeteki
has an LD
50
in mice of 16 micrograms per kilogram. It differs from batrachotoxin, tetrodotoxin, and saxitoxin, the only known nonprotein substances of greater toxicity, as well as from all toxins previously isolated from amphibia.
Transcriptional Repression Mediated by the WT1 Wilms Tumor Gene Product
Authors: Madden Stephen L. , Cook Donna M. , Morris Jennifer F. , Gashler Andrea , Sukhatme Vikas P. , Rauscher Frank J.
Published: October 2006

The
wt1
gene, a putative tumor suppressor gene located at the Wilms tumor (WT) locus on chromosome 11p13, encodes a zinc finger-containing protein that binds to the same DNA sequence as EGR-1, a mitogen-inducible immediate-early gene product that activates transcription. The transcriptional regulatory potential of WT1 has not been demonstrated. In transient transfection assays, the WT1 protein functioned as a repressor of transcription when bound to the EGR-1 site. The repression function was mapped to the glutamine- and proline-rich NH
2
-terminus of WT1; fusion of this domain to the zinc finger region of EGR-1 converted EGR-1 into a transcriptional repressor.
Mechanism for Regulating Cell Surface Distribution of Na
+
,K
+
-ATPase in Polarized Epithelial Cells
Authors: Hammerton Rachel Wilson , Krzeminski Kathleen A. , Mays Robert W. , Ryan Timothy A. , Wollner Debra A. , Nelson W. James
Published: October 2006

Restriction of sodium, potassium adenosine triphosphatase (Na
+
,K
+
-ATPase) to either the apical or basal-lateral membrane domain of polarized epithelial cells is fundamental to vectorial ion and solute transport in many tissues and organs. A restricted membrane distribution of Na
+
,K
+
-ATPase in Madin-Darby canine kidney (MDCK) epithelial cells was found experimentally to be generated by preferential retention of active enzyme in the basal-lateral membrane domain and selective inactivation and loss from the apical membrane domain, rather than by vectorial targeting of newly synthesized protein from the Golgi complex to the basal-lateral membrane domain. These results show how different distributions of the same subunits of Na
+
,K
+
-ATPase may be generated in normal polarized epithelia and in disease states.
Freezing Tolerance in an Adult Insect
Authors: Miller L. Keith
Published: October 2006

The adult carabid beetle
Pterostichus brevicornis
tolerates freezing under natural conditions. Laboratory tests confirm that winter beetles tolerate temperatures below -35°C, whereas summer beetles die if frozen at -6.6°C. Winter beetles can be cooled to about -10°C before freezing, and they thaw near -3.5°C. Summer beetles thaw at -0.7°C. To avoid freezing damage even in winter beetles, cooling rates must be near 20°C per hour or less.
Fungi Associated with Stalactite Growth
Authors: Went F. W.
Published: October 2006

A fungus,
Cephalosporium lamellaecola
, was found to be regularly associated with the active tip of stalactites; crystallization of CaCO
3
occurred on hyphae suspended from the stalactite wall in the terminal drop.
Thyrocalcitonin: Evidence for Physiological Function
Authors: Gray T. Kenney , Munson Paul L.
Published: October 2006

A calcium salt given by stomach tube in modest amounts, such as might be ingested in a normal meal, produced hypercalcemia in acutely thyroidectomized fasted rats, whereas in rats with intact thyroid glands the same dose of calcium had little or no detectable effect, presumably because of release of thyrocalcitonin. Thyrocalcitonin apparently protects against hypercalcemia during feeding after deprivation.
Berberine: Complex with DNA
Authors: Krey Anne K. , Hahn Fred E.
Published: October 2006

A complex of calf-thymus DNA with berberine sediments in the analytical ultracentrifuge. The DNA produced systematic changes in the absorption spectrum of berberine which suggest that single alkaloid molecules bind to DNA. Flow dichroism of purines and pyrimidines and of berberine in the complex with DNA had the same signs and magnitudes. Berberine shifted the thermal strand separation profile of DNA to higher temperatures. Therefore, the alkaloid forms a complex with DNA, probably by intercalation.
DQ Herculis: Synchronous Photometry
Authors: Nather R. Edward , Warner Brian
Published: October 2006

Synchronous signal averaging, applied to the photometry of the steller system DQ Herculis in order to study the 71.1-second pulsations discovered by Walker in 1956, yields a light curve which is a pure sinusoid, within the accuracy of measurement. The binary period is increasing, probably as a result of mass lost from the system.