bluuebunny/crossref_metadata_2025 huggingface dataset:
Catabolic Regulation of the Expression of the Major Myelin Glycoprotein by Schwann Cells in Culture
Authors: Brunden Kurt R. , Windebank Anthony J. , Poduslo Joseph F.
Published: October 2006

Previous studies have suggested that neonatal Schwann cell cultures deprived of axonal contact do not express components of the myelin membrane, including the major myelin glycoprotein, P0. In contrast, Schwann cells from permanently transected, adult nerve exhibit continued biosynthesis of P0 after culture, suggesting that the ability to express the myelin glycoprotein may depend on the degree of cellular differentiation. To examine further the ability of Schwann cell cultures to express P0 as a function of age, we have performed precursor incorporation studies on endoneurial explants from 4‐ to 12‐day‐old rat sciatic nerves after 5 days in culture. The data reveal that explants from 12‐day‐old animals synthesize detectable levels of this integral myelin protein when assayed by [3H]mannose incorporation, even though there is no apparent myelin assembly in the cultures. Pulse–chase analysis of cultures from 12‐day‐old rats demonstrates that [3H]mannose‐labeled P0 is substantially degraded within 3 h. This catabolism largely can be prevented by the addition of swainsonine, ammonium chloride, or L‐methionine methyl ester to the pulse‐chase media. The former agent alters oligosaccharide processing whereas the latter two compounds inhibit lysosomal function. The P0 synthesized by the 12‐day explant cultures following the addition of swainsonine is readily fucosylated, implying that the protein has progressed at least as far as the medial Golgi before its exit and subsequent catabolism. If cultures from 4‐, 6‐, and 8‐day‐old animals are analyzed for P0 biosynthesis by [3H]mannose incorporation in the presence of swainsonine, detectable levels of the glyoprotein are seen. The inability to demonstrate the presence of P0 in earlier studies of neonatal cultures was presumably due in part to the rapid lysosomal catabolism of the protein after translation.
Development of Benzodiazepine and Picrotoxin (t‐Butylbicyclophosphorothionate) Binding Sites in Rat Cerebellar Granule Cells in Culture
Authors: Squires Richard F. , Saederup Else , Damgaard Inge , Schousboe Arne
Published: October 2006

The specific bindings of [3H]flunitrazepam ([3H]FLU), [3H]CGS 8216, and t‐[35S]butylbicyclophosphorothionate ([35S]TBPS) to sites on rat cerebellar granule cells all increase from 4 to 15 days in culture, although their time courses differ. Specific [3H]FLU binding doubles, [3H]CGS 8216 binding triples, and [35S]TBPS binding increases about fourfold from 4 to 15 days in culture. Displacement studies, using the type I‐selective ligand CL 218,872, indicate that at 4 days the [3H]FLU binding sites are almost entirely “type II,'’judging from an IC50 value near 300 nM and a pseudo‐Hill number near 1. By 10 days, approximately equal numbers of type I and type II binding sites are present in the cultured cells, and this ratio remains constant thereafter (12 and 15 days). At days 10–15, both the IC50 value for CL 218,872 (near 100 nM) and the pseudo‐Hill number (near 0.7) remain constant and are significantly different from the values at culture day 4. The development of specific [35S]TBPS binding parallels that of [3H]CGS 8216 binding more closely than the development of [3H]FLU binding. The [3H]CGS 8216/[3H]FLU ratio increased by a factor of 1.6 from day 4 to day 15 (p < 0.001). Taken together, our data suggest the existence of several γ‐aminobutyric acidA (GA‐BAA) receptor subunits, the relative proportions of which change during development. The presence of the GABA‐mimetic 4,5,6,7‐tetrahydroisoxazolo[5,4c]pyridine‐3‐ol (THIP) in the culture medium had no apparent effect on any of the binding sites studied, although THIP was shown previously to induce low‐affinity GABA binding sites.
Treatment with Oxiracetam or Choline Restores Cholinergic Biochemical and Pharmacological Activities in Striata of Decorticated Rats
Authors: Consolo S. , Salmoiraghi P. , Amoroso D. , Kolasa K.
Published: October 2006

Interruption of the corticostriatal pathway by undercutting the frontal cortex resulted after 2 weeks in a 40% reduction of basal acetylcholine (ACh) release in vivo, and in inhibition of the striatal sodium‐dependent high‐affinity uptake of choline (SDHACU) to the same extent. The lesion, too, completely prevented the rise (about 35%) in striatal ACh content induced by oxotremorine and apomorphine acting at muscarine and dopamine receptors, respectively. Acute intraperitoneal injections of 100 mg/kg of either oxiracetam or choline chloride resulted in time‐dependent recovery of ACh output from the striata of decorticated rats to control levels. Oxiracetam also normalized the ex vivo striatal SDHACU activity of decorticated rats 2 h after administration without any effect in sham‐operated rats. Oxiracetam or choline chloride administered before oxotremorine (0.8 mg/kg, i.p.) or apomorphine (1 mg/kg, i.p.) reinstated the ACh‐increasing effect of these agonists. It is suggested that choline chloride acts directly simply by being the precursor for ACh, whereas oxiracetam may act indirectly, possibly by increasing the availability of choline chloride for ACh synthesis. Furthermore, the frontally decorticated rat could constitute a useful model for studying means to restore the deficit in striatal cholinergic neurotransmission.
Selective Increase in S‐100β Protein by Aging in Rat Cerebral Cortex
Authors: Kato Kanefusa , Suzuki Fujiko , Morishita Rika , Asano Tomiko , Sato Tsuneko
Published: October 2006

Changes in the cocentrations of nervous tissuerelated proteins and their isoproteins, such as S‐100 proteins (S‐100α and S‐100β), enolase isozymes (α‐enolase and γ‐enolase), and GTP‐binding proteins (Goα, Gi2α, and β‐subunits), were determined in the CNS of male rats of various ages (from 2 to 30 months old) by means of enzyme immunoassay. The weights of brains and the concentrations of soluble proteins in the cerebral cortex, cerebellum, and brainstem were constant during the observation period. The concentration of S‐100β protein, which is predominantly localized in glial cells, increased gradually in the cerebral cortex with age; levels in the 25‐month‐old rats increased to approximately 150% of the levels in the young (2‐month‐old) rats. However, the S‐100β concentrations in the cerebellum and brainstem were relatively constant, showing similar values in rats 2–30 months old. Levels of other proteins, including both neuronal (γ‐enolase and Goα) and glial (α‐enolase and S‐100α) marker proteins, did not change significantly with age in the cerebral cortex, cerebellum, and brainstem. These results suggest that there is a close relation between the age‐dependent changes of the CNS function and S‐100β protein levels in the cerebral cortex.
Quantification of metamorphopsia in a macular hole patient using M‐CHARTS™
Authors: Arimura Eiko , Matsumoto Chota , Okuyama Sachiko , Takada Sonoko , Hashimoto Shigeki , Shimomura Yoshikazu
Published: October 2006

Purpose:  In cases of macular hole, metamorphopsia is one of the most important symptoms, along with decreased visual acuity and a central scotoma. We investigated the relationship between the degree of metamorphopsia and the morphological appearance of macular holes.

Methods:  Using M‐CHARTS™ developed by ourselves, we quantified the metamorphopsia scores in 35 eyes with an idiopathic macular hole in 35 patients. Metamorphopsia in eyes with macular hole was characterized by straight lines recognized by the subject as bending toward the central scotoma. We also evaluated best corrected visual acuity (VA) and the central 10 degrees of differential light sensitivity using the Octopus 101 program M2. The size of the macular hole and the fluid cuff were measured using a scanning laser ophthalmoscope. We also evaluated the improvement in metamorphopsia scores after surgical treatment for macular hole in 22 patients.

Results:  A significant correlation was found between metamorphopsia score and fluid cuff size, but not diameter of the macular hole. After vitrectomy, VA improved in 14 of 22 patients and metamorphopsia scores improved in 19 of 22 patients. M‐CHARTS™ is a simple and useful method for the quantification and follow‐up of metamorphopsia in patients with macular hole.
Studies on the Mechanism of Antibacterial Action of 2-Methyl-1,4-Naphthoquinone
Authors: Colwell Charlotte A. , McCall Mary
Published: October 2006

Thioglycolic acid neutralized with sodium carbonate, sodium thioglycolate (Eastman), ethyl mercaptan, cysteine hydrochloride and certain sulfur-containing reducing agents (sodium bisulfite and sodium hydrosulfite) antagonize the antibacterial action of 2-methyl-1,4-naphthoquinone on
Escherichia coli
in a synthetic medium. Other reducing agents such as stannous chloride, potassium formate and sodium thiosulfate, show no such antagonism. The antibacterial activities of 2-methyl-3-chloro-1,4-naphthoquinone and 2,6-dimethyl-1,4-naphthoquinone are also abolished by excess thioglycolate and cysteine, while that of 2-methyl-3-methoxy-1,4-naphthoquinone with -OCH
3
instead of -Cl or -H in the 3 position on the quinone ring, is not. These findings suggest that the mode of antibacterial action of 2-methyl-1,4-naphthoquinone is by blocking essential enzymes through combination with sulfhydryl groups, or through combination with sulfhydryl groups of essential bacterial metabolites. This combination may take place in the 3-position on the quinone ring. This mode of action is similar to that suggested by other investigators for several antibiotic agents including penicillin. The antibacterial activity of the methoxy quinone, however, even in the presence of sulfhydryl groups, suggests that the foregoing explanation may not be the complete one.
New Horizons in Medical Research
Authors: Van Slyke C. J.
Published: October 2006

From the above it is seen that the U. S. Public Health Service Research Grants program represents a sincere and continuing effort to supply Federal funds for the support of necessary additional research in the fields of medical and related sciences without interposing any degree of government restriction, control, supervision, or regimentation. The program is a scientific one, scientific guidance of which lies wholly in the hands of scientists.
Basal Forebrain and Hypothalamic Connection to Frontal and Parietal Cortex in the Rhesus Monkey
Authors: Kievit Job , Kuypers Henricus G. J. M.
Published: October 2006

Horseradish peroxidase was injected in different parts of the frontal and parietal cortex in 17 rhesus monkeys. In all cases the enzyme was transported retrogradely to neurons in the substantia innominata and hypothalamus as well as in the thalamus. These new findings demonstrate that these cortical areas receive direct afferent fibers from limbic basal forebrain areas concerned with emotion and motivation.
Adaptive Significance of Synchronized Breeding in a Colonial Bird: A New Hypothesis
Authors: Emlen Stephen T. , Demong Natalie J.
Published: October 2006

Bank swallows nest gregariously in colonies usually ranging from 10 to 300 nests. Different pairs within the same colony are highly synchronized with each other, and 67 percent of the nests fledged their young over a period of only 6 days. This high degree of synchronization is demonstrated to be of adaptive significance. Reproductive fitness increases as a function of the precision of synchrony of the colony. It is proposed that social foraging plays an important role in maximizing the feeding efficiency in this species and that asynchronous breeding decreases the effectiveness of this social foraging, particularly in late nesters and among young, newly fledged birds. An individual that fledges either early or at the peak of synchrony will emerge to find a steady stream of other birds traveling to local, ephemeral, concentrations of food. The late emerger finds itself practically alone and thus is deprived of the potential benefits of the pooled information about locations of food resources available to the full colony.
Aerobic Sulfate Reduction in Microbial Mats
Authors: Canfield Donald E. , Des Marais David J.
Published: October 2006

Measurements of bacterial sulfate reduction and dissolved oxygen (O
2
) in hypersaline bacterial mats from Baja California, Mexico, revealed that sulfate reduction occurred consistently within the well-oxygenated photosynthetic zone of the mats. This evidence that dissimilatory sulfate reduction can occur in the presence of O
2
challenges the conventional view that sulfate reduction is a strictly anaerobic process. At constant temperature, the rates of sulfate reduction in oxygenated mats during daytime were similar to rates in anoxic mats at night: thus, during a 24-hour cycle, variations in light and O
2
have little effect on rates of sulfate reduction in these mats.
Clathrate Hydrate Formation in Amorphous Cometary Ice Analogs in Vacuo
Authors: Blake David , Allamandola Louis , Sandford Scott , Hudgins Doug , Freund Friedemann
Published: October 2006

The presence of clathrate hydrates in cometary ice has been suggested to account for anomalous gas release at large radial distances from the sun as well as the retention of volatiles in comets to elevated temperatures. However, how clathrate hydrates can form in low-pressure environments, such as in cold interstellar molecular clouds, in the outer reaches of the early solar nebula, or in cometary ices, has been poorly understood. Experiments performed with the use of a modified electron microscope demonstrate that during the warming of vapor-deposited amorphous ices in vacuo, clathrate hydrates can form by rearrangements in the solid state. Phase separations and microporous textures that are the result of these rearrangements may account for a variety of anomalous cometary phenomena.
Presynaptic Facilitation as a Mechanism for Behavioral Sensitization in
Aplysia
Authors: Castellucci V. , Kandel E. R.
Published: October 2006

Sensitization is an elementary form of nonassociative learning, related to behavioral arousal, in which a strong stimulus facilitates a reflex response. Studies of the neural circuit of the gill-withdrawal reflex in the isolated abdominal ganglion of
Aplysia
indicate that short-term sensitization is due to presynaptic facilitation. The facilitation results in a sudden increase in the amount of neurotransmitter released by the sensory neurons at their synapses with motor neurons.
Retinoic Acid Binding Protein: Occurrence in Human Tumors
Authors: Ong David E. , Page David L. , Chytil Frank
Published: October 2006

Extracts of human carcinomas from lung and breast contain a protein which binds retinoic acid (vitamin A acid) with high specificity. The binding protein was not detected in normal lung or breast tissue from the same patients.
Enemy Specification in the Alarm-Recruitment System of an Ant
Authors: Wilson Edward O.
Published: October 2006

Many kinds of ants use odor trails to recruit nestmates to food discoveries and new nest sites; minor workers of the myrmicine
Pheidole dentata
also use them to recruit major workers ("soldiers") to the vicinity of intruders. This newly discovered alarm-recruitment system has proved to be narrowly specific. Only fire ants and other members of the genus
Solenopsis
, which include some of the potentially most dangerous enemies of
Pheidole
, have been found to evoke the response when present as single scouts or small invading forces. The glandular source of the
Pheidole
trail pheromone and the cues by which
Pheidole
recognize Solenopsis have been experimentally determined.
Lymphocytes of the Toad
Xenopus laevis
Have the Gene Set for Promoting Tadpole Development
Authors: Wabl M. R. , Brun R. B. , Du Pasquier L.
Published: October 2006

Nuclear transplantation experiments show that differentiated cells, such as lymphocytes, from the adult frog can express the genes necessary for tadpole development. The transplanted cells were proven to be lymphocytes by immunological methods. The origin of the tadpoles that developed after lymphocyte nuclei injections was ascertained by a karyotypic marker.
Loss of X-Cells in Lateral Geniculate Nucleus with Monocular Paralysis: Neural Plasticity in the Adult Cat
Authors: Brown Dawn L. , Salinger Walter L.
Published: October 2006

Chronic immobilization of one eye by cranial nerve resection in adult cats led to selective but substantial loss of X-cells in the binocular segment of the dorsal lateral geniculate nucleus.
Mechanisms of Oxygen Metabolism
Authors: Mason H. S.
Published: October 2006

The enzymes which catalyze reactions of molecular oxygen occur in three principle classes: (i) oxygen transferases, (ii) mixed function oxidases, and (iii) electron transferases. The first class catalyzes the transfer of a molecule of molecular oxygen to substrate. The second class catalyzes the transfer of one atom of the oxygen to substrate; the other atom undergoes two-equivalent reduction. The third class catalyzes the reduction of molecular oxygen to hydrogen peroxide or to water.
Prostaglandin B
1
: The L-Shaped Prostaglandin
Authors: DeTitta George T.
Published: October 2006

The crystal and molecular structure of prostaglandin B
1
(PGB
1
) has been determined. The conformation is L-shaped, with the α and ω side chains roughly perpendicular to one another. This arrangement differs from the "hairpin" or approximately parallel disposition of side chains observed for other prostaglandins. The ω chain, which normally turns at the 15-hydroxyl back toward the α chain, is fully extended. The conformation is stabilized by the conjugation of the dienone chromophore. The 15-hydroxyl, which is normally directed away from the centroid of the prostaglandin in the hairpin model, is turned inward in L-shaped PGB
1
. The low biological activity of PGB
1
in many systems and especially its inhibition of the metabolizing enzyme 15-hydroxyprostaglandin dehydrogenase may be attributable directly to the observed L-shape conformation.
Morphine-Induced Rotation in Naive, Nonlesioned Rats
Authors: Jacquet Yasuko F. , Carol Marilyn , Russell Ian S.
Published: October 2006

In rats injected with morphine in the midbrain reticular formation, pronounced ipsilateral rotation behavior was elicited by mild auditory and visual stimuli. The frequency of occurrence and rate of rotation were dose-dependent. This effect was site specific and drug specific; other drugs (except heroin) failed to induce this behavior. Naloxone potentiated the morphine rotation. Pretreatment with drugs that either potentiated or attenuated the morphine rotation indicated involvement of the noradrenergic and cholinergic systems and excluded a role for the dopaminergic system. No analgesia was observed after morphine microinjection in this site; thus, the hyperresponsivity to mild auditory and visual stimuli and concurrent analgesia previously seen in animals with morphine microinjections in the periaqueductal gray matter appear to be dissociable effects of morphine, and site specific.
Strontium-Calcium Movement from Soil to Man
Authors: Comar C. L. , Russell R. Scott , Wasserman R. H.
Published: October 2006

The calcium reservoirs of the biosphere are becoming labeled to varying degrees with strontium-90 from nuclear weapons. These reservoirs include the human and animal skeleton, the milk, the vegetation, the upper layers of soil, and the waters. The degree of labeling is governed by the dilution that occurs, or the differential behavior of calcium and strontium in various steps of the food chain. This differential behavior normally provides a factor of protection against strontium-90 in the soil and vegetation that may be as high as 25 for the newborn and is most likely not less than 6 for adults, depending on food habits.

The physiological steps that are important in the movement of the two elements in the biosphere are described to provide a basis for an approach toward increase of the discrimination against strontium in favor of calcium. Some aspects of agricultural practices are discussed from this standpoint. The matter of hazard from levels now existing and the present need to undertake remedial measures are not discussed, in major part because of lack of experimental data on which to base such considerations.
Inherited Electrophoretic Hemoglobin Patterns among 20 Inbred Strains of Mice
Authors: Russell Elizabeth S. , Gerald Park S.
Published: October 2006

The hemoglobin from mice of six inbred strains is of the single-spot electrophoretic type, and that from 14 inbred strains is of the diffuse type. No selective advantage is apparent for either type. The distribution among strains shows some relation to the history of the development of the strains.
Incidence of Familial Hyperlipemia
Authors: Hirschhorn Kurt , Hirschhorn Rochelle , Fraccaro Marco , Böök Jan A.
Published: October 2006

Familial hyperlipemia is an inherited disease associated with early onset of coronary atherosclerosis. In a survey of a student population in Sweden, an estimated case incidence of 2 to 3 percent was discovered. This study also demonstrates that there is probably a heterogeneity of causes for the primary elevation of blood triglycerides in man.
Biochemical Responses of Rats to Auditory Stress
Authors: Jurtshuk Peter , Weltman A. Stanley , Sackler Arthur M.
Published: October 2006

Prolonged, intense auditory stimulation caused a marked reduction in glutathione levels in the blood of female rats. The frequency of the response was significant statistically and was related inversely to the recovery rate after auditory stimulation. An increase in adrenal weights and ascorbic acid, as well as a decrease in total adrenal cholesterol, were noted.
Poleward Migration of Early Angiosperm Flora
Authors: Axelrod Daniel I.
Published: October 2006

1) During the opening phase of the Early Cretaceous (Neocomian), angiosperms commenced to invade lowland basins of deposition at generally lower latitudes. They reached high northern and middle southern latitudes at the close of the epoch (Albian) and only replaced the relict Jurassic-type vegetation at high latitudes during the early part of Late Cretaceous time.

2) This poleward migration of angiosperms is consistent with the theory that the phylum had its center of origin and dispersal at tropical latitudes, which ranged between 45°N and 45°S in pre-Cretaceous time.

3) Recognition of the time-space factor involved in the Early Cretaceous poleward migration of angiosperms removes most of the conflicts in the testimony on age supplied by fossil plants and by marine invertebrates-conflicts which have persisted for nearly a century.
Coiling Direction of
Globigerina pachyderma
as a Climatic Index
Authors: Ericson David B.
Published: October 2006

An interdependence between the geographical distribution of dextral and sinistral populations of the planktonic foraminifer,
Globigerina pachyderma
, and sea surface-temperatures is demonstrated. It is inferred that changes in dominant coiling direction at lower levels in sediment cores from the North Atlantic record southward shifts of isotherms during the last ice age.
Escape and Avoidance Conditioning in Human Subjects without Their Observation of the Response
Authors: Hefferline Ralph F. , Keenan Brian , Harford Richard A.
Published: October 2006

An invisibly small thumb-twitch increased in rate of occurrence when it served, via electromyographic amplification, to terminate or postpone aversive noise stimulation. Subjects remained ignorant of their behavior and its effect. Their cumulative response curves resembled those obtained in similar work with animals. Other subjects, informed of the effective response, could not produce it deliberately in a size small enough to qualify for reinforcement.
Blood Flow Rates by Nuclear Magnetic Resonance Measurements
Authors: Singer J. R.
Published: October 2006

Blood flow rates may be determined by nuclear magnetic resonance relaxation time measurements. A set of experiments carried out on the flow of blood in mice tails has demonstrated the feasibility of the scheme. Two simple measurement methods are described, and the pertinent equations are given. In addition, some procedures for using nuclear magnetic resonance and electron paramagnetic resonance for tracing the flow of specific materials in the body are outlined.
Role of Olfactory Sense in Pregnancy Block by Strange Males
Authors: Bruce H. M. , Parrott D. M. V.
Published: October 2006

Pregnancy is blocked in a high proportion of recently mated female mice exposed to strange males. This reaction is virtually abolished by the prior removal of the olfactory bulbs of the female. The smell of the strange male appears to be the primary stimulus in the exteroceptive block to pregnancy in mice.
Automatic Tonometer with Exact Theory: Various Biological Applications
Authors: Mackay R. Stuart , Marg Elwin , Oechsli Raymond
Published: October 2006

Methods for externally measuring pressure within body cavities exist. In tonometer form they are fast and gentle not requiring anesthetics for the cornea of the human eye. Readings are accurate and independent of tissue tension, corneal stiffness, astigmatic curvatures, and surface tension. There are also separate indications of corneal rigidity and relaxation, and tonographic fluid expression. Other applications include monitoring blood pressure, uterine contractions, and infant intracranial pressure.
Vivax
-Type Malaria Parasite of Macaques Transmissible to Man
Authors: Eyles Don E. , Coatney G. Robert , Getz Morton E.
Published: October 2006

Transmission of
Plasmodium cynomolgi bastianellii
from rhesus monkeys to two human subjects by
Anopheles freeborni
and the occurrence of attacks of malaria in two other laboratory workers not exposed to human malaria suggests the existence of an animal reservoir of infection complicating malaria control and eradication.
Cloning of a Second Type of Activin Receptor and Functional Characterization in
Xenopus
Embryos
Authors: Mathews Lawrence S. , Vale Wylie W. , Kintner Chris R.
Published: October 2006

A complementary DNA coding for a second type of activin receptor (ActRIIB) has been cloned from
Xenopus laevis
that fulfills the structural criteria of a transmembrane protein serine kinase. Ectodermal explants from embryos injected with activin receptor RNA show increased sensitivity to activin, as measured by the induction of muscle actin RNA. In addition, injected embryos display developmental defects characterized by inappropriate formation of dorsal mesodermal tissue. These results demonstrate that this receptor is involved in signal transduction and are consistent with the proposed role of activin in the induction and patterning of mesoderm in
Xenopus
embryos.
In Vivo Gene Transfer with Retroviral Vector-Producer Cells for Treatment of Experimental Brain Tumors
Authors: Culver Kenneth W. , Ram Zvi , Wallbridge Stuart , Ishii Hiroyuki , Oldfield Edward H. , Blaese R. Michael
Published: October 2006

Direct in situ introduction of exogenous genes into proliferating tumors could provide an effective therapeutic approach for treatment of localized tumors. Rats with a cerebral glioma were given an intratumoral stereotaxic injection of murine fibroblasts that were producing a retroviral vector in which the herpes simplex thymidine kinase (HS-tk) gene had been inserted. After 5 days during which the HS-tk retroviral vectors that were produced in situ transduced the neighboring proliferating glioma cells, the rats were treated with the anti-herpes drug ganciclovir. Gliomas in the ganciclovir- and vector-treated rats regressed completely both macroscopically and microscopically. This technique exploits what was previously considered to be a disadvantage of retroviral vectors—that is, their inability to transfer genes into nondividing cells. Instead, this feature of retroviruses is used to target gene delivery to dividing tumor cells and to spare nondividing neural tissue.
Avian Uptake of Fission Products from an Area Contaminated by Low-Level Atomic Wastes
Authors: Willard William K.
Published: October 2006

Birds living on the Oak Ridge White Oak Lake bed, an area contaminated by low-level atomic wastes, revealed a striking seasonal difference in uptake of fission products. Because the omnivorous diet of passerine birds is ecologically comparable to the mixed diet of man, uptake of radionuclides by wild birds provides an assay of amounts to be expected at the trophic level of primary interest to man.
Allelic Genes in the Housefly Producing Modified Enzymes That Cause Organophosphate Resistance
Authors: Oppenoorth F. J. , van Asperen K.
Published: October 2006

In all of six phosphate-resistant strains of
Musca domestica
L. a mutant gene is present which produces an altered ali-esterase. The modified enzymes are no longer irreversibly inhibited by the oxygen analogs of the insecticides to which the strains are resistant but can slowly convert them. In five of the strains the resistance is caused by this gene only.
Oxygen Equilibrium of Brachiopod
Lingula
Hemerythrin
Authors: Manwell Clyde
Published: October 2006

In contrast to hemerythrin from five different species of sipunculid worms, ecardine brachiopod
Lingula
hemerythrin has an oxygen equilibrium which is reversibly altered by
p
H changes, both the oxygen affinity (Bohr effect) and the interactions between oxygen-binding centers being a function of
p
H. The significance of these phenomena is discussed in view of the phylogenetic distribution of hemerythrin and the function of respiratory pigments.
Relationship between Reaction Time and Electroencephalographic Alpha Phase
Authors: Callaway Enoch , Yeager Charles L.
Published: October 2006

Demonstrations of a relationship between human 8 to 13 per second (alpha) electroencephalographic activity and simple visual reaction time can be made at reliable levels of confidence by (i) sampling reaction times to stimuli given at phases of the alpha cycle 10 msec apart, (ii) selecting the phase with the slowest reaction times, and (iii) collecting enough reaction times to stimuli at this and some other control phase for statistical comparison.
Crystal Structure Refinement of Reedmergnerite, the Boron Analog of Albite
Authors: Clark Joan R. , Appleman Daniel E.
Published: October 2006

Ordering of boron in a feldspar crystallographic site
T
1
(0) has been found in reedmergnerite, which has silicon-oxygen and sodium-oxygen distances comparable to those in isostructural low albite. If a simple ionic model is assumed, calculated bond strengths yield a considerable charge imbalance in reedmergnerite, an indication of the inadequacy of the model with respect to these complex structures and of the speculative nature of conclusions based on such a model.
IP
3
Receptor: Localization to Plasma Membrane of T Cells and Cocapping with the T Cell Receptor
Authors: Khan Adil A. , Steiner Joseph P. , Klein Michael G. , Schneider Martin F. , Snyder Solomon H.
Published: October 2006

Immune responses in lymphocytes require cellular accumulation of large amounts of calcium (Ca
2+
) from extracellular sources. In the T cell tumor line Jurkat, receptors for the Ca
2+
-releasing messenger inositol 1,4,5-trisphosphate (IP
3
) were localized to the plasma membrane (PM). Capping of the T cell receptor-CD3 complex, which is associated with signal transduction, was accompanied by capping of IP
3
receptors. The IP
3
receptor on T cells appears to be responsible for the entry of Ca
2+
that initiates proliferative responses.
Emerging Principles for the Recognition of Peptide Antigens by MHC Class I Molecules
Authors: Matsumura Masazumi , Fremont Daved H. , Peterson Per A. , Wilson lan A.
Published: October 2006

Class I major histocompatibility complex (MHC) molecules interact with self and foreign peptides of diverse amino acid sequences yet exhibit distinct allele-specific selectivity for peptide binding. The structures of the peptide-binding specificity pockets (subsites) in the groove of murine H-2K
b
as well as human histocompatibility antigen class I molecules have been analyzed. Deep but highly conserved pockets at each end of the groove bind the amino and carboxyl termini of peptide through extensive hydrogen bonding and, hence, dictate the orientation of peptide binding. A deep polymorphic pocket in the middle of the groove provides the chemical and structural complementarity for one of the peptide's anchor residues, thereby playing a major role in allele-specific peptide binding. Although one or two shallow pockets in the groove may also interact with specific peptide side chains, their role in the selection of peptide is minor. Thus, usage of a limited number of both deep and shallow pockets in multiple combinations appears to allow the binding of a broad range of peptides. This binding occurs with high affinity, primarily because of extensive interactions with the peptide backbone and the conserved hydrogen bonding network at both termini of the peptide. Interactions between the anchor residue (or residues) and the corresponding allele-specific pocket provide sufficient extra binding affinity not only to enhance specificity but also to endure the presentation of the peptide at the cell surface for recognition by T cells.
Time-out from Positive Reinforcement
Authors: Azrin N. H.
Published: October 2006

When an organism can itself impose extinction during fixed-ratio food reinforcement, the duration of the extinction period is a function of the number of responses required for reinforcement. Typically, the subject imposes extinction at the start of the usual fixed-ratio run.
Soil Mineralogy as Factor in Spread of
Fusarium
Wilt of Banana
Authors: Stotzky Guenther , Dawson J. E. , Martin R. Torrence , Ter Kuile C. H. H.
Published: October 2006

A correlation is established between the spread of
Fusarium
wilt of banana and soil mineralogy. Montmorillonoid-type clay minerals occur in all soils in which disease spread is slow, but, with the exception of two soils, this group of minerals is absent in soils in which it is rapid.
Applications of Fluorescent Brighteners in Biological Techniques
Authors: Darken Marjorie A.
Published: October 2006

The visual labeling of various microorganisms has been accomplished with specific fluorescent ultraviolet-absorbing compounds that not only have been bound by the cell but have been transferred by it to subsequent growth. The possibility of application to genetic studies is suggested.
Rapid Development of Drug-Resistant Mutants of Poliovirus
Authors: Melnick Joseph L. , Crowther Derek , Barrera-Oro Julio
Published: October 2006

Guanidine hydrochloride is a potent inhibitor of poliovirus synthesis in cell culture. However, the viral progeny which do grow in the presence of guanidine may become approximately 10,000 times more resistant to the drug. The phenomenon of drug resistance poses yet another problem in the search for a satisfactory viral chemotherapeutic agent.
Effect of Ribonuclease on Retention of Conditioned Response in Regenerated Planarians
Authors: Corning W. C. , John E. R.
Published: October 2006

Conditioned planarians were transected and allowed to regenerate in a ribonuclease solution or in pond water. Heads which had regenerated in ribonuclease displayed a retention level equal to that of head and tail sections which had regenerated in pond water. However, tails regenerated in ribonuclease performed randomly although they could be retrained to criterion.
Photoperiodic Response of Female Fringe-Toed Lizards
Authors: Mayhew Wilbur W.
Published: October 2006

Uma notata
females were held over the winter under 24 hours of light per day. These animals laid from two to four clutches of eggs, with 4 to 7 weeks between clutches. Clutches contained two to four eggs. Additional light is believed to be more important than heat in causing this response.
Nucleotide-Iron-Sulfur Cluster Signal Transduction in the Nitrogenase Iron-Protein: the Role of Asp
125
Authors: Wolle Dana , Dean Dennis R. , Howard James Bryant
Published: October 2006

Electron transfer in nitrogenase involves a gating process initiated by MgATP (magnesium adenosine triphosphate) binding to Fe-protein. The redox site, an 4Fe:4S cluster, is structurally separated from the MgATP binding site. For MgATP hydrolysis to be coupled to electron transfer, a signal transduction mechanism is proposed that is similar to that in guanosine triphosphatase proteins. Based on the three-dimensional structure of Fe-protein, Asp
125
is likely to be part of a putative transduction path. Altered Fe-protein with Glu replacing Asp has been prepared and retains the ability for the initial nucleotide-dependent conformational change. However, either MgADP or MgATP can induce the shift and Mg binding to the nucleotide is no longer essential.
Intestinal Transport of Selenium-75 Selenomethionine
Authors: Spencer Richard P. , Blau Monte
Published: October 2006

When measured simultaneously, selenium-75 selenomethionine accumulated identically with sulfur-35 methionine across everted hamster intestinal sacs in the presence of carrier methionine. The apparent
K
m
for L-methionine transport was 0.8 × 10
-3
M
, as calculated from the beta emissions of S
35
-methionine or the gamma emissions of Se
75
-selenomethionine. Absorption of Se
75
-selenomethionine from the gastrointestinal tract of man also occurred, with peak blood levels being reached in about 3 hours. Because of the 122-day half-life of selenium-75 and its multiple gamma emissions, Se
75
-selenomethionine may serve as a tool in evaluating amino-acid absorption.
3,4,3′,4′-Tetrachloro Azoxybenzene and Azobenzene: Potent Inducers of Aryl Hydrocarbon Hydroxylase
Authors: Poland Alan , Clover Edward , Kende Andrew S. , DeCamp Mark , Giandomenico Christen M.
Published: October 2006

Two unwanted contaminants, 3,4,3′,4′-tetrachloroazoxybenzene (TCAOB) and 3,4,3′,4′-tetrachloroazobenzene (TCAB), formed in the commercial synthesis of 3,4-dichloroaniline or of herbicides made from 3,4-dichloroaniline, were responsible for three outbreaks of acne among chemical workers. TCAOB and TCAB are approximately isosteric to 2,3,7,8-tetrachlorodibenzo-
p
-dioxin and 2,3,7,8-tetrachlorodibenzofuran, two well-known contaminants that cause acne. All four of these agents are potent inducers of hepatic aryl hydrocarbon hydroxylase activity and compete for stereospecific binding sites in the hepatic cytosol, which are thought to be the receptor sites for the induction of this enzyme. Among the chlorinated azoxy and azobenzenes, the potency of a congener to induce aryl hydrocarbon hydroxylase activity correlates with its binding affinity for the hepatic cytosol specific binding sites and its capacity to induce acne; this relation between structure and activity parallels that observed for the chlorinated dibenzo-
p
-dioxins and dibenzofurans.
Some Effects of Room Acoustics on Evoked Auditory Potentials
Authors: Marsh James T. , Worden F. G. , Hicks L.
Published: October 2006

Auditory potentials were recorded from bipolar electrodes chronically implanted in the cochlear nuclei of four cats. In a training box modified to reduce echoes these animals were exposed to clicks and tone pulses presented from an overhead speaker. Slight changes in the position of the animal in the resulting sound field produced marked changes in the potentials evoked from the cochlear nucleus. These phenomena were observed in the unanesthetized, unrestrained subjects as well as in those under Nembutal anesthesia. It is suggested that these acoustic effects complicate the analysis and interpretation of potentials evoked from the cochlear nucleus under conditions of habituation, shifts in attention, and learning.
Regulation of Adenylyl Cyclase from
Paramecium
by an Intrinsic Potassium Conductance
Authors: Schultz Joachim E. , Klumpp Susanne , Benz Roland , Schürhoff-Goeters Wilhelm J. Ch. , Schmid Angela
Published: October 2006

Hyperpolarization of the cell membrane of
Paramecium
stimulates adenosine 3′,5′-monophosphate (cAMP) formation. Manipulations of the K
+
resting conductance of the ciliate by adaptation in different buffers affected excitability of the cAMP generating system. Blockade of K
+
channels inhibited hyperpolarization-stimulated cAMP formation. A mutant of
Paramecium
that is unable to control its K
+
resting conductance had a defect in cAMP formation. Purified adenylyl cyclase, when incorporated into an artificial lipid bilayer membrane, revealed properties of a voltage-independent K
+
channel. This indicates that the adenylyl cyclase of
Paramecium
has a secondary function as carrier of the K
+
resting conductance. A hyperpolarization-activated K
+
efflux appears to directly regulate adenylyl cyclase activity in vivo.
Computer as Aid in Describing Form in Gastropod Shells
Authors: Raup David M.
Published: October 2006

The basic form of many coiled gastropod shells can be defined by four parameters. A digital computer with automatic plotting equipment can be used to make graphical reconstructions of a shell from any given values of the four parameters.
Marrow Chimerism in Marmosets
Authors: Benirschke K. , Anderson J. M. , Brownhill L. E.
Published: October 2006

In the femoral marrow of three adult marmosets, two male
Callithrix jacchus
and one female
Leontocebus rosalia
, a number of opposite-sexed metaphases were found. It is inferred that this chimeric state resulted from intrauterine placental anastomoses between heterosexual twins. The lack of the freemartin effect in connection with this chimerism is discussed, and the structural nature of the Y chromosome in the Callithricidae is described.
Binocular Combination of Projected Images
Authors: Land Edwin H. , Daw Nigel W.
Published: October 2006

Two color-separation positive transparencies of a scene, one projected with "red" light and the other with tungsten lamp light, were superimposed on a screen. The light was polarized so that an observer wearing an appropriate viewer could either see both images in each eye or the "red" image in one eye and the "white" image in the other. These two situations gave different results, not the same results, as some previous investigators have claimed. Land's major results cannot be "obtained stereoscopically." We conclude that the process by which color is formed could possibly be a process of the retina or the lateral geniculate body, and does not necessarily have to be a process of the cerebral cortex as implied by the binocular experiments which purported to give the fuller gamut of color.
Surface Textures of Sand Grains—an Application of Electron Microscopy: Glaciation
Authors: Krinsley David , Takahashi Taro
Published: October 2006

To simulate glacial conditions, a mixture of ice and quartz grains was subjected to grinding under hydrostatic pressure of 500 bars. Electron microphotographs of these "synthetic" glaciated surfaces were then compared with electron microphotographs of grain surfaces which had been abraded and crushed by glacial action, and the correspondence was found to be good. Thus it appears possible to distinguish glacial sands from beach and eolian sands by examining the surface textures of these grains with the electron microscope.
Modulation of the Dimerization of a Transcriptional Antiterminator Protein by Phosphorylation
Authors: Amster-Choder Orna , Wright Andrew
Published: October 2006

The transcriptional antiterminator protein BglG inhibits transcription termination of the bgl operon in Escherichia coli when it is in the nonphosphorylated state. The BglG protein is now shown to exist in two configurations, an active, dimeric nonphosphorylated form and an inactive, monomeric phosphorylated form. The migration of BglG on native polyacrylamide gels was consistent with it existing as a dimer when nonphosphorylated and as a monomer when phosphorylated. Only the nonphosphorylated dimer was found to bind to the target RNA. When the dimerization domain of the λ repressor was replaced with BglG, the resulting chimera behaved like an intact λ repressor in its ability to repress λ gene expression, which suggests that BglG dimerizes in vivo. Repression by the λ-BglG hybrid was significantly reduced by BglF, the BglG kinase, an effect that was relieved by conditions that stimulate dephosphorylation of BglG by BglF. These results suggest that the phosphorylation and the dephosphorylation of BglG regulate its activity by controlling its dimeric state.
Continuous Extraction during Treatment with Ultrasound
Authors: Lott J. A. , DeMaggio A. E.
Published: October 2006

A variety of constituents from plants can be extracted in an apparatus of simple design in which the plant material and fresh supplies of solvent are exposed together in an ultrasonic tank.
Proprioceptive Discrimination of a Covert Operant without Its Observation by the Subject
Authors: Hefferline Ralph F. , Perera Thomas B.
Published: October 2006

When the subject occasionally emitted an invisibly small thumb twitch (detected electromyographically), he received a tone as a signal to press a key. After several conditioning sessions, the tone was progressively diminished to zero. The subject nevertheless continued to press the key whenever he emitted a thumb twitch, and he reported that he still heard the tone.
Algae: Nitrogen Fixation by Antarctic Species
Authors: Holm-Hansen Osmund
Published: October 2006

Algae from terrestrial and fresh-water habitats in Antarctica were examined for ability to fix atmospheric nitrogen.
Nostoc commune
was the only species capable of growing in nitrogen-free medium; nitrogen fixation by this species was verified by assimilation of N
15
. The importance of nitrogen-fixing algae to terrestrial life in the Antarctic is discussed.
Bohr Effect: Absence in a Molluscan Hemocyanin
Authors: Redmond James R.
Published: October 2006

The hemocyanin of the keyhole limpet,
Diodora aspera
, shows no Bohr effect within the
p
H range 6.88 to 7.84. At 10°C the pressure of half-saturation is 5 mm-Hg of oxygen pressure. A moderately positive interaction occurs among the oxygen-combining sites during oxygenation. The heat of oxygenation is calculated to be approximately -12.6 kcal/mole of oxygen. The
p
H of normal blood of
Diodora
is lower than that of many other marine molluscs.
Burns and Other Skin Lesions: Microcirculatory Responses in Man during Healing
Authors: Zimmer James G. , Demis D. Joseph
Published: October 2006

Morphological changes in the cutaneous microcirculation during wound healing have been studied by capillaroscopy in man. In experimental and accidental burns, abrasions, and lacerations, in addition to the anticipated revascularization by the deeper dermal vessels, a distinctive pattern of response by the surrounding papillary capillaries was consistently observed. This appears to be a general phenomenon in healing of skin lesions and suggests the possibility that a potent capillary-attracting factor may be produced within the injured tissue.