bluuebunny/crossref_metadata_2025 huggingface dataset:
Localization of Nigral Dopamine-Sensitive Adenylate Cyclase on Neurons Originating from the Corpus Striatum
Authors: Spano P. F. , Trabucchi M. , Di Chiara G.
Published: October 2006

Nigral basal adenylate cyclase and dopamine-sensitive adenylate cyclase, glutamate decarboxylase, choline acetyltransferase, and tyrosine hydroxylase activities were measured in rats with hemitransections at various levels or with electrolytic lesions of the medial forebrain bundle or the crus cerebri. The loss of nigral dopamine-sensitive adenylate cyclase activity after the various brain lesions was correlated with the loss of nigral glutamic acid decarboxylase but not that of tyrosine hydroxylase; nigral choline acetyltransferase was unaffected in all cases. The data indicate that the nigral dopamine-sensitive adenylate cyclase activity may be localized on neurons afferent to the nigra, probably originating from the globus pallidus and possibly from the tail of the caudate. The results suggest that dopamine, released from nigral dendrites, may influence dopaminergic activity indirectly by modulating impulses transmitted to the nigrostriatal neurons through the crus cerebri.
Reexamination of the Folding of BPTI: Predominance of Native Intermediates
Authors: Weissman Jonathan S. , Kim Peter S.
Published: October 2006

Bovine pancreatic trypsin inhibitor (BPTI) continues to be the only protein for which a detailed pathway of folding has been described. Previous studies led to the conclusion that nonnative states are well populated in the oxidative folding of BPTI. This conclusion has broadly influenced efforts to understand protein folding. The population of intermediates present during the folding of BPTI has been reexamined by modern separation techniques. It was found that all well-populated folding intermediates contain only native disulfide bonds. These data emphasize the importance of native protein structure for understanding protein folding.
Resistance to ddI and Sensitivity to AZT Induced by a Mutation in HIV-1 Reverse Transcriptase
Authors: St. Clair M. H. , Martin J. L. , Tudor-Williams G. , Bach M. C. , Vavro C. L. , King D. M. , Kellam P. , Kemp S. D. , Larder B. A.
Published: October 2006

Serial human immunodeficiency virus type-1 (HIV-1) isolates were obtained from five individuals with acquired immunodeficiency syndrome (AIDS) who changed therapy to 2′,3′-dideoxyinosine (ddI) after at least 12 months of treatment with 3′-azido-3′-deoxythymidine (zidovudine, AZT). The in vitro sensitivity to ddI decreased during the 12 months following ddI initiation, whereas AZT sensitivity increased. Analysis of the reverse transcriptase coding region revealed a mutation associated with reduced sensitivity to ddI. When this mutation was present in the same genome as a mutation known to confer AZT resistance, the isolates showed increased sensitivity to AZT. Analysis of HIV-1 variants confirmed that the ddI resistance mutation alone conferred ddI and 2′,3′-dideoxycytidine resistance, and suppressed the effect of the AZT resistance mutation. The use of combination therapy for HIV-1 disease may prevent drug-resistant isolates from emerging.
Regulation of Rransendothelial Neutrophil Migration by Endogenous Interleukin-8
Authors: Huber Andreas R. , Kunkel Steven L. , Todd Robert F. , Weiss Stephen J.
Published: October 2006

Movement of neutrophils from the bloodstream to inflamed tissue depends on the activation of both the neutrophil and the endothelial cell. Endothelial cells lining the postcapillary venule respond to proinflammatory mediators by expressing adhesion molecules and synthesizing a variety of neutrophil-activating factors. Endothelial cell production of a 77-amino acid variant of interleukin-8 (IL-8) was found to be a requirement for the invasion of neutrophils through a vessel wall model. IL-8 secreted by cytokine- or lipopolysaccharide-stimulated endothelial cells induced the rapid shedding of neutrophil lectin adhesion molecule-1, the up-regulation of leukocyte β
2
integrins, and the attachment and transmigration of the neutrophils. Thus, endogenous endothelial IL-8 regulates transvenular traffic during acute inflammatory responses.
Quasars: Millisecond-of-Arc Structure Revealed by Very-Long-Baseline Interferometry
Authors: Knight Curtis A. , Robertson Douglas S. , Rogers Alan E. E. , Shapiro Irwin I. , Whitney Alan R. , Clark Thomas A. , Goldstein Richard M. , Marandino Gerard E. , Vandenberg Nancy R.
Published: October 2006

Observations with the Goldstone-Haystack radio interferometer of the quasars 3C 279 and 3C 273 have disclosed the presence of fine structure in their radio emissions. Although the interpretation is not unique, the fringe-amplitude data for quasar 3C 279 are quite consistent with emissions from two points, each contributing equally to the correlated flux. The separation of the two points is estimated to be (1.55 ± 0.05) × 10
-3
arc second, or about 20 light years at the distance of 3 × 10
9
light years inferred from optical red-shift data. The formal uncertainty in the right-ascension component of the separation is about 6 × 10
-6
arc second; differential proper motion in this direction at half the speed of light could be discerned within a year. The fringe-amplitude data of quasar 3C 273 allow similar, but less definitive, interpretations.
Chemical Communication and "Propaganda" in Slave-Maker Ants
Authors: Regnier F. E. , Wilson E. O.
Published: October 2006

Slave-maker ants of the
Formica sanguinea
group direct their raids by means of odor trails. Artificial trails made from whole-body extracts and extracts of Dufour's glands and hindguts can be used to guide columns of workers to selected target colonies and to initiate raids. In workers of
F. pergandei
and
F. subintegra
, members of the
F. sanguinea
group, the Dufour's glands are hypertrophied and contain large quantities of three acetates (decyl, dodecyl, and tetradecyl), which are discharged at defending workers during the slave raids. The acetates produce very efficient, long-lasting alarm signals that attract the slave-makers but disperse the defenders; in effect, therefore, they are "propaganda substances."
Unilateral Ablation of the Auditory Cortex in the Cat Impairs Complex Sound Localization
Authors: Cranford J. , Ravizza R. , Diamond I. T. , Whitfield I. C.
Published: October 2006

Unilateral ablation of the auditory cortex in the cat results in a profound deficit in attending to stimuli on the side contralateral to the lesion. The deficit is also manifested in an abnormal perception of left-right pulse pairs when the pulse which leads by a few milliseconds is contralateral to the damaged hemisphere.
Detoxication Enzymes in the Guts of Caterpillars: An Evolutionary Answer to Plant Defenses?
Authors: Krieger Robert I. , Feeny Paul P. , Wilkinson Christopher F.
Published: October 2006

Higher activity of midgut microsomal oxidase enzymes in polyphagous than in monophagous species indicates that the natural function of these enzymes is to detoxify natural insecticides present in the larval food plants. Differing strategies of adaptation to plant defenses may partly account for the great diversity of insect herbivores.
Norepinephrine Pools in Rat Brain: Differences in Turnover Rates and Pathways of Metabolism
Authors: Schildkraut Joseph J. , Draskoczy Paul R. , Lo Pallas Sun
Published: October 2006

The rate of disappearance of intracisternally administered [
3
H]norepinephrine from rat brain gradually declines as a multiphasic exponential function of time. Conversion to [
3
H]normetanephrine accounts for a larger fraction of the [
3
H]norepinephrine released in the brain shortly after its intracisternal injection than that released at later times. Pools of norepinephrine in the brain thus appear to differ in their turnover rates and pathways of metabolism. The pool of norepinephrine with a rapid rate of turnover and an appreciable conversion to normetanephrine, identified by the techniques reported here, may correspond to a pool of newly synthesized norepinephrine in the brain.
Free Recall and Abstractness of Stimuli
Authors: Bevan William , Steger Joseph A.
Published: October 2006

The relation of abstractness of stimuli to efficiency of free recall was studied in college and fourth-grade students. Groups were shown a sequence of objects, pictures, and object names and were asked to recall what they had seen. Recall tests were conducted either immediately after presentation of the stimulus-sequence, after 24 hours, or after 1 week. Objects were recalled more frequently than pictures, and pictures more frequently than words. Adults performed better than children, except in the case of objects.
Differential Cerebral Processing of Noise and Verbal Stimuli
Authors: Cohn Robert
Published: October 2006

Psychophysiological measurements have indicated that the right cerebral hemisphere processes noises and other nonverbal data and that the left cerebral hemisphere processes verbal material. Direct physiological measurements, as expressed in summated auditory evoked cortical responses, unequivocally demonstrate that click noises show a greater amplitude of initial output over the right brain, and that verbal stimuli produce either equal or higher amplitudes of output over the left cerebral hemisphere.
Destruction of Mammalian Motor Nerve Terminals by Black Widow Spider Venom
Authors: Okamoto Michiko , Longenecker Herbert E. , Riker Walter F. , Song S. K.
Published: October 2006

Black widow spider venom selectively poisons motor nerve endings. A progressive and irreversible failure of neuromuscular transmission occurs in the cat. Electron microscopy of the poisoned nerve-muscle junction shows a sequence of motor nerve ending damage that culminates in disruption of the prejunctional membrane and loss of all organelles, including synaptic vesicles. The postjunctional membrane was morphologically unaffected. After complete poisoning, the contractile response to exogenous acetylcholine was severely impaired, an indication that the prejunctional site is chiefly involved in the contractile response produced by exogenous acetylcholine and that the pre- and postjunctional effects of acetylcholine were separated.
Plutonium-244: Confirmation as an Extinct Radioactivity
Authors: Alexander E. C. , Lewis R. S. , Reynolds J. H. , Michel M. C.
Published: October 2006

The mass spectrum of xenon from spontaneous fission in a laboratory sample of plutonium-244 is precisely what meteoriticists predicted it would be; this discovery completes a web of proof that this nuclide is a bona fide extinct radioactivity of galactic origin, that r-process nucleosynthesis was ongoing in the galaxy at the time of the birth of the sun, and that the early meteoritic abundances of plutonium-244, heretofore tentative, can be utilized with confidence in models for the chronology of galactic nucleosynthesis. The search for an explanation for anomalous fission-like xenon in carbonaceous chondrites can now be narrowed.
Pheromones: Isolation of Male Sex Attractants from a Female Primate
Authors: Michael Richard P. , Keverne E. B. , Bonsall R. W.
Published: October 2006

Fractionation of vaginal secretions from rhesus monkeys by partitioning and chromatographic procedures, combined with behavioral studies, demonstrates that short-chain aliphatic acids are responsible for stimulating the sexual behavior of males. Injection of estradiol into ovariectomized females increases the concentration of volatile acids in secretions which will then sexually stimulate these male primates.
Odor Differences between Enantiomeric Isomers
Authors: Russell G. F. , Hills J. I.
Published: October 2006

The enantiomers of
R
- and
S
- carvone,
R
- and
S
- carvotanacetone,
R
- and
S
-
trans
-dihydrocarvone, and
R
- and
S
-
cis
-dihydrocarvone were synthesized from
R
- and
S
- carvone, and all were subjected to gas-liquid chromatographic purification. Sensory analysis of the highly purified compounds revealed odor differences between enantiomeric pairs.
Sintered Diamond Compacts with a Cobalt Binder
Authors: Katzman Howard , Libby W. F.
Published: October 2006

Diamond powder can be successfully cemented with cobalt. At 62 kilobars the sintering occurs over the temperature range from 1570° to 1610°C. The maximum microhardness of the compact (> 3000 kilograms per square millimeter on the Knoop scale) is obtained with a mixture of 20 percent cobalt (by volume) and a diamond particle size of 1 to 5 micrometers.
Histochemical Fluorescence of Raphe Neurons: Selective Enhancement by Tryptophan
Authors: Aghajanian George K. , Asher Irving M.
Published: October 2006

The histochemical fluorescence of those neurons in brainstem raphe nuclei which are presumed to contain serotonin is selectively and stereospecifically enhanced by L-tryptophan at doses that also produce an elevation in the concentration of serotonin. However, contrary to our assumptions, the increase in raphe fluorescence is not prevented byp-chlorophenylalanine, an inhibitor of serotonin synthesis. These results suggest that under some conditions derivatives of tryptophan other than, or in addition to, serotonin may be of significance in raphe neurons.
Magnetocardiography of Direct Currents: S-T Segment and Baseline Shifts during Experimental Myocardial Infarction
Authors: Cohen David , Norman J. C. , Molokhia F. , Hood W.
Published: October 2006

Magnetocardiograms with a bandwidth of 0 to 40 hertz were recorded from intact dogs undergoing myocardial infarction. This was done with a superconducting magnetometer in a magnetically shielded room. The purpose was to look for the steady currents of injury from the heart which supposedly produce much of the S-T segment shifts during infarction. These heart currents cannot be measured with surface electrodes because of direct-current interference from other sources, such as from the contact potential between electrode and skin. The magnetocardiograms showed both S-T segment shifts and direct currents as a result of infarction. However, they also showed that the S-T segment shifts were not produced by the direct currents. It is unlikely that these direct currents originated from the infarcted area, and their exact origin is not yet known.
Functional Contribution of Neuronal AChR Subunits Revealed by Antisense Oligonucleotides
Authors: Listerud Mark , Brussaard Arjen B. , Devay Píreska , Colman David R. , Role Lorna W.
Published: October 2006

Although multiple related genes encoding nicotinic acetylcholine receptor (AChR) subunits have been identified, how each of these subunits contributes to AChRs in neurons is not known. Sympathetic neurons express four classes of AChR channels and six AChR subunit genes (α3, α4, α5, α7, β2, and β4). The contribution of individual subunits to AChR channel subtypes in these neurons was examined by selective deletion with antisense oligonucleotides. An α3 antisense oligonucleotide decreased the number and altered the properties of the normally expressed ACh-activated channels. The remaining AChR channels have distinct biophysical and pharmacological properties that indicate an important functional contribution of the α7 subunit.
Drug Abuse Control: Policy Turns toward Rehabilitation
Authors: Walsh John
Published: October 2006

Heroin addiction is the most difficult to control and the most socially destructive form of addiction in America today. Heroin is a fact of life and a cause of death among an increasing number of citizens in America, and it is heroin addiction that must command priority in the struggle against drugs.—President Nixon in his drug message to Congress on 17 June.
Nitric Oxide Air Pollution: Detection by Optoacoustic Spectroscopy
Authors: Kreuzer L. B. , Patel C. K. N.
Published: October 2006

Nitric oxide is detected by a new technique in which tunable infrared radiation from a spin-flip Raman laser is used to measure the absorption spectrum of a gas sample by optoacoustic spectroscopy. This technique is sensitive enough to detect a concentration of 0.01 part per million of nitric oxide pollution in air samples.
Normal Atmosphere: Large Radical and Formaldehyde Concentrations Predicted
Authors: Levy H.
Published: October 2006

A steady-state model of the normal (unpolluted) surface atmosphere predicts a daytime concentration of hydroxyl, hydroperoxyl, and methylperoxyl radicals approaching 5 × 10
8
molecules per cubic centimeter and a formaldehyde concentration of 5 × 10
10
molecules per cubic centimeter or 2 parts per billion. A radical chain reaction is proposed for the rapid removal of carbon monoxide, leading to a carbon monoxide lifetime as low as 0.2 year in the surface atmosphere.
Brain Serotonin Content: Physiological Dependence on Plasma Tryptophan Levels
Authors: Fernstrom John D. , Wurtman R. J.
Published: October 2006

Brain serotonin concentrations at 1 p.m. were significantly elevated 1 hour after rats received a dose of L-tryptophan (12.5 milligrams per kilogram. intraperitoneally) smaller than one-twentieth of the normal daily dietary intake. Plasma and brain tryptophan levels were elevated 10 to 60 minutes after the injection, but they never exceeded the concentrations that occur nocturnally in untreated animals as a result of their normal 24-hour rhythms. These data suggest that physiological changes in plasma tryptophan concentration influence brain serotonin levels.
Trout Leukocytes: Growth in Oxygenated Cultures
Authors: Heckman J. R. , Allendorf F. W. , Wright J. E.
Published: October 2006

A reproducible method of culturing leukocytes from rainbow trout (
Salmo gairdneri
) has been found. Using an atmosphere of 100 percent oxygen, we stimulated peripheral blood leukocytes to divide at 19°C. Cultured cells were used for a karyological study; they had a modal chromosome number of 60 and a constant arm number of 104, a value previously reported for other tissues in these fish.
Melatonin and Abnormal Movements Induced by L-Dopa in Mice
Authors: Cotzias G. C. , Tang L. C. , Miller S. T. , Ginos J. Z.
Published: October 2006

Melatonin has blocked adventitious movements induced by L-dopa in intact mice. It has reversed the adventitious turning to the right, and it has induced running to the left in mice receiving L-dopa after a lesion in the right caudate nucleus.
Songs of Humpback Whales
Authors: Payne Roger S. , McVay Scott
Published: October 2006

1) Humpback whales (
Megaptera novaeangliae
) produce a series of beautiful and varied sounds for a period of 7 to 30 minutes and then repeat the same series with considerable precision. We call such a performance "singing" and each repeated series of sounds a "song."

2) All prolonged sound patterns (recorded so far) of this species are in song form, and each individual adheres to its own song type.

3) There seem to be several song types around which whales construct their songs, but individual variations are pronounced (there is only a very rough species-specific song pattern).

4) Songs are repeated without any obvious pause between them; thus song sessions may continue for several hours.

5) The sequence of themes in successive songs by the same individual is the same. Although the number of phrases per theme varies, no theme is ever completely omitted in our sample.

6) Loud sounds in the ocean, for example dynamite blasts, do not seem to affect the whale's songs.

7) The sex of the performer of any of the songs we have studied is unknown.

8) The function of the songs is unknown.
Follicle-Stimulating Hormone and the Regulation of Testosterone Secretion in Rabbit Testes
Authors: Johnson Bryan H. , Ewing Larry L.
Published: October 2006

Regulation of testosterone secretion is presumably mediated by interstitial cell-stimulating hormone (ICSH). However, there is little information on the actions of other chemical messengers in regulating testosterone secretion. We have shown that follicle-stimulating hormone augments testosterone secretion stimulated by ICSH in rabbit testes perfused in vitro with an artificial medium.
Neuronal Circuit Mediating Escape Responses in Crayfish
Authors: Zucker Robert S. , Kennedy Donald , Selverston Allen I.
Published: October 2006

The neuronal circuit underlying rapid abdominal flexion in response to phasic tactile stimulation comprises identified afferents, interneurons of two orders, a decision unit, and several motor neurons. The circuit is organized hierarchically as a "cascade" in which electrical synapses predominate at higher levels. Behavioral habituation results from lability at chemical junctions early in the pathway.
Human Fetal Cerebellar Cortex: Organization and Maturation of Cells in vitro
Authors: Lapham Lowell W. , Markesbery William R.
Published: October 2006

Human fetal cerebellar cortex was maintained up to 5 months in vitro. Important features included early migration of granule neurons followed by maturation of Purkinje and granule neurons. Unique areas of organization developed in which a rim of leptomeningeal cells surrounded an explant and its outgrowth zone; these areas subsequently grew as well-defined units.
Serum Parathyroid Hormone in X-Linked Hypophosphatemia
Authors: Arnaud Claude , Glorieux Francis , Scriver Charles
Published: October 2006

Serum immunoreactive parathyroid hormone (IPTH) is normal in patients with X-linked hypophosphatemic rickets who are not treated with phosphate salts. Phosphate raises IPTH in these patients. Endogenous IPTH does not influence the existing defect in tubular reabsorption of phosphate in male patients.
Dental Caries: Prospects for Prevention
Authors: Scherp Henry W.
Published: October 2006

Combined utilization of measures now available or imminent could reduce caries of the crowns of the teeth to the point of negligibility as a public health problem, if public desire were great enough to motivate changes in some of our habits. Universal optimum application of fluoride and substitution of starchy foods for sugary ones (or even simply judicious consumption of sugar) would alone do most of the job. Sealing of susceptible occlusal areas with adhesive polymers promises to protect the sites where fluoride evidently cannot be maximally effective. It seems unlikely that any single measure will be found sufficient to control this multifactorial disease. Consequently, we must continue the search for new means to increase the caries resistance of teeth, to reduce the cariogenicity of foodstuffs, and to check the deleterious activities of cariogenic bacteria. Anticaries food additives and antibacterial agents for intraoral use seem to be approaching practicability. Past performance warrants expectation that ongoing fundamental investigations will produce leads for future development and application.
Perception of Changes in Certain Exteroceptive Stimuli
Authors: Notterman J. M. , Filion R. D. L. , Mandriota F. J.
Published: October 2006

Although cybernetic models of one sort or another have become quite common in behavioral research, and although these models theoretically require a capacity for system detection of changes in error, no general psychophysical description of the individual human being's ability to discriminate different rates of stimulation is available. An initial survey of this type has been attempted and is reported here.

For reasons which appear to be related to the biological mechanisms underlying sensory information processing, it is concluded, first, that ancillary cues of rate-related final magnitude are more valuable than cues of stimulus duration; second, that direct attention to on-going change is less precise than attention to final values only; and third, that differences in isochronal stimulus rates occurring in place or extent are more readily perceived than differences in isochronal rate of change in energy content, at least for the stimuli and ranges examined.
Estrogen Target Sites in the Brain of the Chick Embryo
Authors: Martinez-Vargas M. Christine , Gibson Douglas B. , Sar Madhabananda , Stumpf Walter E.
Published: October 2006

Autoradiograms prepared from brains of chick embryos after injection of [
3
H]estradiol demonstrate the existence of target cells for estrogen in the medial preoptic and ventral hypothalamic regions as early as day 10 of incubation. Target cells also appear in telencephalic, diencephalic, and mesencephalic locations during later stages of embryonic development. These hormone-concentrating cells probably are the anatomical substrate for the formative action of sex steroids during embryonic life on certain brain functions, such as control of sexual and aggressive behavior and gonadotropin secretion.
Information Processing in the Primate Visual System: An Integrated Systems Perspective
Authors: Van Essen David C. , Anderson Charles H. , Felleman Daniel J.
Published: October 2006

The primate visual system contains dozens of distinct areas in the cerebral cortex and several major subcortical structures. These subdivisions are extensively interconnected in a distributed hierarchical network that contains several intertwined processing streams. A number of strategies are used for efficient information processing within this hierarchy. These include linear and nonlinear filtering, passage through information bottlenecks, and coordinated use of multiple types of information. In addition, dynamic regulation of information flow within and between visual areas may provide the computational flexibility needed for the visual system to perform a broad spectrum of tasks accurately and at high resolution.
DNA Binding Activity of Recombinant SRY from Normal Males and XY Females
Authors: Harley Vincent R. , Jackson David I. , Hextall Patrick J. , Hawkins J. Ross , Berkovitz Gary D. , Sockanathan Shanthini , Lovell-Badge Robin , Goodfellow Peter N.
Published: October 2006

The protein encoded by the human testis determining gene,
SRY
, contains a high mobility group (HMG) box related to that present in the T cell-specific, DNA-binding protein TCF-1. Recombinant SRY protein was able to bind to the same core sequence AACAAAG recognized by TCF-1 in a sequence dependent manner. In five XY females point mutations were found in the region encoding the HMG box. In four cases DNA binding activity of mutant SRY protein was negligible; in the fifth case DNA binding was reduced. These results imply that the DNA binding activity of SRY is required for sex determination.
Experimental Phylogenetics: Generation of a Known Phylogeny
Authors: Hillis David M. , Bull James J. , White Mary E. , Badgett Marty R. , Molineux Ian J.
Published: October 2006

Although methods of phylogenetic estimation are used routinely in comparative biology, direct tests of these methods are hampered by the lack of known phylogenies. Here a system based on serial propagation of bacteriophage T7 in the presence of a mutagen was used to create the first completely known phylogeny. Restriction-site maps of the terminal lineages were used to infer the evolutionary history of the experimental lines for comparison to the known history and actual ancestors. The five methods used to reconstruct branching pattern all predicted the correct topology but varied in their predictions of branch lengths; one method also predicts ancestral restriction maps and was found to be greater than 98 percent accurate.
On the Probability of Matching DNA Fingerprints
Authors: Risch Neil J. , Devlin B.
Published: October 2006

Forensic scientists commonly assume that DNA fingerprint patterns are infrequent in the general population and that genotypes are independent across loci. To test these assumptions, the number of matching DNA patterns in two large databases from the Federal Bureau of Investigation (FBI) and from Lifecodes was determined. No deviation from independence across loci in either database was apparent. For the Lifecodes database, the probability of a three-locus match ranges from 1 in 6,233 in Caucasians to 1 in 119,889 in Blacks. When considering all trios of five loci in the FBI database, there was only a single match observed out of more than 7.6 million comparisons. If independence is assumed, the probability of a five-locus match ranged from 1.32 × 10
-12
in Southeast Hispanics to 5.59 × 10
-14
in Blacks, implying that the minimum number of possible patterns for each ethnic group is several orders of magnitude greater than their corresponding population sizes in the United States. The most common five-locus pattern can have a frequency no greater than about 10
-6
. Hence, individual five-locus DNA profiles are extremely uncommon, if not unique.
Reversal of Integration and DNA Splicing Mediated by Integrase of Human Immunodeficiency Virus
Authors: Chow Samson A. , Vincent Karen A. , Ellison Viola , Brown Patrick O.
Published: October 2006

In retroviral integration, the viral integration protein (integrase) mediates a concerted DNA cleavage-ligation reaction in which the target DNA is cleaved and the resulting 5′ ends of target DNA are joined to the 3′ ends of viral DNA. Through an oligonucleotide substrate that mimics the recombination intermediate formed by this initial cleavage-ligation reaction, the purified integrase of human immunodeficiency virus was shown to promote the same reaction in reverse, a process called disintegration. Analysis of a set of structurally related substrates showed that integrase could promote a range of DNA cleavage-ligation reactions. When the viral DNA component of the disintegration substrate was single-stranded, integrase could mediate a DNA splicing reaction analogous to RNA splicing.
Murine Leukemia Virus: High-Frequency Activation in vitro by 5-Iododeoxyuridine and 5-Bromodeoxyuridine
Authors: Lowy D. R. , Rowe W. P. , Teich N. , Hartley J. W.
Published: October 2006

Cells of embryos of the high leukemic mouse strain AKR can be grown in culture as virus-negative cell lines. However, these lines and clonal sublines uniformly have the capacity to initiate synthesis of murine leukemia virus. Exposure of the cells to 5-iododeoxyuridine or 5-bromodeoxyuridine induced synthesis of virus in as high as 0.1 to 0.5 percent of the cells; many of the cells were producing virus as soon as 3 days after initiation of treatment. Induction of virus by these drugs is several orders of magnitude greater than that obtained with any other treatment tested. These studies indicate that the full genome of murine leukemia virus is present in an unexpressed form in all AKR cells and provide a potentially powerful technique for activating leukemia virus genomes in other cell systems.
Freezing and Melting of Lipid Bilayers and the Mode of Action of Nonactin, Valinomycin, and Gramicidin
Authors: Krasne Sally , Eisenman George , Szabo Gabor
Published: October 2006

An abrupt loss of effectiveness of the presumed carriers, nonactin and valinomycin, in mediating ion conductance occurred at the same temperature as the membrane fluidity, judged visually, was lost. By contrast, the effects of the presumed channel-former, gramicidin, were the same on solid and liquid membranes. Taken together, these findings imply that freezing the membrane primarily reduces the mobility of these antibiotics with little effect on their solubility.
Operant Conditioning of Specific Patterns of Neural and Muscular Activity
Authors: Fetz Eberhard E. , Finocchio Dom V.
Published: October 2006

In awake monkeys we recorded activity of single "motor" cortex cells, four contralateral arm muscles, and elbow position, while operantly reinforcing several patterns of motor activity. With the monkey's arm held semiprone in a cast hinged at the elbow, we reinforced active elbow movements and tested cell responses to passive elbow movements. With the cast immobilized we reinforced isometric contraction of each of the four muscles in isolation, and bursts of cortical cell activity with and without simultaneous suppression of muscle activity. Correlations between a precentral cell and specific arm muscles consistently appeared under several behavioral conditions, but could be dissociated by reinforcing cell activity and muscle suppression.
Sensory Neglect Produced by Lateral Hypothalamic Damage
Authors: Marshall John F. , Turner Blair H. , Teitelbaum Philip
Published: October 2006

Unilateral lateral hypothalamic lesions in rats produce deficits in orientation to contralateral visual, olfactory, whisker-touch, and somatosensory stimuli. This syndrome of sensory neglect appears to be involved in some of the deficits in feeding and attack which follow bilateral lateral hypothalamic lesions.
Crystal Structure of a Naturally Occurring Dinucleoside Monophosphate: Uridylyl (3′,5′) Adenosine Hemihydrate
Authors: Rubin J. , Brennan T. , Sundaralingam M.
Published: October 2006

The crystal structure of uridylyl (3′,5′) adenosine hemihydrate has been analyzed by x-ray diffraction. The two independent molecules found in the asymmetric unit exhibit conformations that differ significantly from those found in double-helical RNA. The conformational information obtained from this analysis provides considerable insight into the possible conformations of nonhelical "loop" regions of transfer RNA, as well as single-stranded regions of nucleic acids in general.
Limulus
Lateral Eye: Properties of Receptor Units in the Unexcised Eye
Authors: Barlow Robert B. , Kaplan Ehud
Published: October 2006

Single receptor units in the compound eye of the horseshoe crab were illuminated, and their impulse discharges were recorded without removing the eye from the animal. The receptors were spontaneously active in darkness and responded without saturation over a light intensity range of 10
10
to 1. When the eye was excised, the receptors did not discharge in darkness and had an intensity range of 10
5
to 1, as is usually found. Experiments show that these and other differences result from cutting off the blood supply to the eye when it is excised. In addition, the range and shape of the intensity characteristic suggest that more than one receptor mechanism encodes light intensity in this eye.
Potassium Ion Release and Enzyme Secretion: Adrenergic Regulation by α-and β-Receptors
Authors: Batzri Samuel , Selinger Zvi , Schramm Michael
Published: October 2006

Epinephrine caused amylase secretion and K
+
release in rat parotid slices. Propranolol, which blocks β-receptors, inhibited amylase secretion; phentolamine, which blocks α-receptors, inhibited K
+
release. Since enzyme secretion was associated with fusion of secretory granules to the cell membrane and K
+
release was associated with vacuole formation, it could be shown that both α- and β-receptors are present in the same exocrine cell. The findings appear to exclude cyclic 3′,5′-adenosine monophosphate as an intermediate in the α-receptor response.
Three-Dimensional Structure Identified from Single Sections
Authors: Elias Hans
Published: October 2006

Errors in the identification of objects have been made frequently because of faulty interpretation of their flat images or sections. Such errors are perpetuated through a strange psychological chain reaction.

1) The first author who observes sections of an object, although presenting faithful pictures of sections of it, identifies its shape incorrectly. Such an initial mistake may be due to identification of the flat image with the object itself or to failure to consider the shape of the image as a function of the shape of the real object and the angle and level of cutting.

2) The first author describes verbally his personal concept of the object.

3) The reader reads the text of a publication before or without examining the pictorial evidence.

4) The reader's belief in the authority of the printed word immunizes him against critical evaluation of the evidence.

5) The reader regards a published opinion as a "fact."

6) A mechanism of suppression of new evidence is set up in the brain of the reader in favor of previously published, verbalized concepts. His brain unconsciously rejects new concepts that might arise intracerebrally. The printed word supersedes visual evidence.

7) A secondary mechanism parallels steps 3 to 6. An observer notices an unfamiliar figure in the microscope. Following established procedures for scientific investigations, he refrains from forming an opinion about his observation. Instead he rushes to the library searching for similar, published observations. If he finds a previous report about a similar shape, he accepts it as a "fact" and he "confirms" the previously printed viewpoint. Let me interject a personal experience concerning this mechanism. I investigated the arrangement of blood vessels in the human liver by means of corrosion preparations. The work was divided between an assistant and me. He was assigned the task of preparing drawings of two specimens. In his drawings he showed a structure which was absent from the specimens but had been described in a previous publication.

This article shows simple ways for correct initial identification of shape and structure and for the breaking of the reverberating circuit of erroneous thinking.
The Origins of Taxonomy
Authors: Raven Peter H. , Berlin Brent , Breedlove Dennis E.
Published: October 2006

There are approximately 10 million kinds of organisms in the world, of which we have described some 15 percent. The rapid growth of the human population will cause most of the remainder to disappear from the earth before they are seen by a taxonomist. These facts suggest a more rigorous application of priorities in systematic biology as well as a careful review of the principles upon which our taxonomic system is based.

Folk taxonomies all over the world are shallow hierarchically and comprise a strictly limited number of generic taxa ranging from about 250 to 800 forms applied to plants and a similar number applied to animals. These numbers are consistent, regardless of the richness of the environment in which the particular people live. Very few specific and varietal taxa are recognized in folk taxonomic systems. Until the invention of movable type in the mid-l5th century, written taxonomies were simply records of the folk taxonomies of particular regions. Subsequently, with the possibility for the wide distribution of books, it began to seem worth while to attempt to describe and name all species of plants and animals in the world. By the year 1700, 698 genera of plants were recognized; and by the year 1778, some 1350 genera, including tens of thousands of species. In 1789 de Jussieu interpolated the family as a higher level taxonomic category in an attempt to reduce the number of important units in the system to a memorable number. The family is still the focal point in systems of angiosperm classification at present, several hundred families being recognized.

Problems with the taxonomic system stem largely from the fact that it is not designed as an information retrieval device. In folk taxonomies, names are given to organisms and these are used to communicate about the organisms with others who already know the culturally significant properties of the organisms being discussed. In dealing with the vast numbers of organisms that exist, we tend to overemphasize the process of classification and the decisions it involves at the expense of the information about the organisms that we are supposedly accumulating. Frequent changes in names exacerbate the difficulties of the system and render it still less useful for information retrieval.

With modern electronic data processing equipment, it has become possible to record information about organisms, to retain this information in a data bank, and to utilize it for various purposes, including the construction of various taxonomic systems. The invention of high-speed electronic data processing equipment is seen as analogous to but more important than the invention of movable type in the history of systematic biology. By using such equipment to its full potentialities, we should be able to achieve a qualitative improvement in our perception of the living world.
The Energy Landscapes and Motions of Proteins
Authors: Frauenfelder Hans , Sligar Stephen G. , Wolynes Peter G.
Published: October 2006

Recent experiments, advances in theory, and analogies to other complex systems such as glasses and spin glasses yield insight into protein dynamics. The basis of the understanding is the observation that the energy landscape is complex: Proteins can assume a large number of nearly isoenergetic conformations (conformational substates). The concepts that emerge from studies of the conformational substates and the motions between them permit a quantitative discussion of one simple reaction, the binding of small ligands such as carbon monoxide to myoglobin.
Voluntary Control of Human Cardiovascular Integration and Differentiation through Feedback and Reward
Authors: Schwartz Gary E.
Published: October 2006

Human subjects can learn to control the relation between their systolic blood pressure and heart rate when they are given feedback and reward for the desired pattern of blood pressure and heart rate. They can learn to integrate these functions (increase or decrease both jointly), or to a lesser degree, differentiate them (raise one and simultaneously lower the other). The extent of this learning is predicted by a behavioral and biological model that explains specificity of learning in the autonomic nervous system.
Temperature Regulation in the Bumblebee
Bombus vagans
: A Field Study
Authors: Heinrich Bernd
Published: October 2006

Bombus vagans
forages for nectar at 5°C in shade and at 31°C in sunshine. The production of heat while the bumblebee is on flowers, at ambient temperatures below 24°C, helps to maintain a thoracic temperature that is near the minimum for flight between flowers. However, at ambient temperatures above 24°C the thoracic temperature is no longer regulated at 32° to 33°C and rises.
Archeology and the Art Market
Authors: Coggins Clemency
Published: October 2006

The illegal antiquities market is financing the destruction of the remains of pre-Columbian civilization. In the United States, this process has often been aided by museums, collectors, and scholars who have unwittingly collaborated. Recently, initiatives toward reform have been taken by UNESCO, professional organizations, and two academic institutions. Further organized action is recommended.
Bone Marrow: The Bursa Equivalent in Man?
Authors: Abdou Nabih I. , Abdou Nancy L.
Published: October 2006

Human bone marrow lymphoid cells, particularly when enriched with plasma cells, as in multiple myeloma, respond to pokeweed mitogen and to antiserum to immunoglobulin but not to phytohemagglutinin. Cells of patients with X-linked agammaglobulinemia of the bursal deficient type failed to respond to either pokeweed or to the antiserum to immunoglobulin. Leukocytes of the agammaglobulinemia patients however responded in a normal fashion to phytohemagglutinin. Just as the in vitro response to phytohemagglutinin is taken as an index of the thymus-dependent system, the in vitro response to both antiserum to immunoglobulin and pokeweed may be considered an index for the bursal-dependent system. Human bone marrow, therefore, contains bursal cells and probably very few or no thymus cells.
Detection of High-Molecular-Weight RNA in Particles from Human Milk
Authors: Schlom J. , Spiegelman S. , Moore D. H.
Published: October 2006

Particles from human milk contain a reverse transcriptase and a high-molecular-weight (60
S
to 70
S
) RNA that serves as a template. These particles have two features diagnostic of known RNA tumor viruses.
Δ
9
-Tetrahydrocannabinol: Dose-Related Effects on Timing Behavior in Chimpanzee
Authors: Conrad Donald G. , Elsmore Timothy F. , Sodetz Frank J.
Published: October 2006

Δ
9
-Tetrahydrocannabinol, at doses within the effective range for humans, was administered orally to chimpanzees with stable, efficient timing performances maintained by multilink chained schedules of food reinforcement. Reinforcements decreased with increasing dose, because of decreased frequencies of total operant timing responses and decreased accuracy of the timing performances which did occur. Higher doses exerted an effect for up to 3 days.
Spiral Waves of Chemical Activity
Authors: Winfree Arthur T.
Published: October 2006

The Zhabotinsky-Zaikin reagent propagates waves of chemical activity. Reaction kinetics remain to be fully resolved, but certain features of wave behavior are determined by purely geometrical considerations. If a wave is broken, then spiral waves, resembling involutes of the circle, appear, persist, and eventually exclude all concentric ring waves.
Magnetoencephalography: Detection of the Brain's Electrical Activity with a Superconducting Magnetometer
Authors: Cohen David
Published: October 2006

Measurements of the brain's magnetic field, called magnetoencephalograms (MEG's), have been taken with a superconducting magnetometer in a heavily shielded room. This magnetometer has been adjusted to a much higher sensitivity than was previously attainable, and as a result MEG's can, for the first time, be taken directly, without noise averaging. MEG's are shown, simultaneously with the electroencephalogram (EEG), of the alpha rhythm of a normal subject and of the slow waves from an abnormal subject. The normal MEG shows the alpha rhythm, as does the EEG, when the subject's eyes are closed; however, this MEG also shows that higher detector sensitivity, by a factor of 3, would be necessary in order to clearly show the smaller brain events when the eyes are open. The abnormal MEG, including a measurement of the direct-current component, suggests that the MEG may yield some information which is new and different from that provided by the EEG.