bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Chicken Ribosomal RNA Genes and Construction of Lambda Hybrids Containing Gene Fragments
Authors: McClements W. , Skalka A. M.
Published: October 2006

The ribosomal RNA genes (ribosomal DNA) of chicken are present in approximately 200 copies and are cleaved into two fragments of molecular weight 5 × 10
6
and 12 to 14 × 10
6
by restriction endonuclease Eco RI. Recombinant phages have been constructed in vitro by joining the smaller fragment of ribosomal DNA and the outer arms of DNA from the vector λgt
WES
⋅λC. In one of the recombinants, the coding strand of the cloned fragment is in the proper orientation for transcription with λ "early" genes; in the other two the orientation is reversed, with the coding strand in the proper position for transcription with λ "late" genes.
Sesquiterpene Progenitor, Germacrene A: An Alarm Pheromone in Aphids
Authors: Bowers William S. , Nishino Chikao , Montgomery Michael E. , Nault Lowell R. , Nielson Mervin W.
Published: October 2006

Germacrene A, the elusive biogenetic "parent" of many sesquiterpenes, has been isolated from the spotted alfalfa aphid and identified as a new intrageneric aphid alarm pheromone.
Ratio of Plasma Alpha Amino-
n
-Butyric Acid to Leucine as an Empirical Marker of Alcoholism: Diagnostic Value
Authors: Morgan Marsha Y. , Milsom Judith P. , Sherlock Sheila
Published: October 2006

The ratio of plasma alpha amino-
n
-butyric acid to leucine was raised in patients with both alcohol-related and nonalcohol-related liver disease. This ratio appears to act as a relatively nonsensitive index of hepatocellular dysfunction rather than an index of alcoholism.
Histone Occurrence in Chromatin from
Peridinium balticum
, a Binucleate Dinoflagellate
Authors: Rizzo Peter J. , Cox Elenor R.
Published: October 2006

Peridinium balticum
is one of two dinoflagellates known to have dissimilar nuclei together in the same cell. One nucleus (dinokaryotic) has permanently condensed chromosomes, while the other (eukaryotic) does not have morphologically distinct chromosomes. Acid extracts of chromatin prepared from a mixture of dinokaryotic and eukaryotic nuclei and purified eukaryotic nuclei give four bands that co-migrate with four of the five histones from calf thymus when analyzed in urea-containing polyacrylamide gels.
Phagocytosis in the Retinal Pigment Epithelium of the RCS Rat
Authors: Goldman Arnold I. , O'Brien Paul J.
Published: October 2006

The retinal pigment epithelium of RCS rats, previously thought not to phagocytize photoreceptor outer segments, exhibited a peak of phagocytosis in vivo when animals were kept under conditions of cyclic lighting (12 hours of darkness and 12 hours of light). This peak occurred at 1 hour after the onset of light, with maximum and minimum levels of phagocytosis averaging about 5 percent of that found in the pigment epithelium of Osborn-Mendel rats used as a control. Eyecups that were obtained from Osborn-Mendel rats and maintained for up to 3 hours in organ culture demonstrated levels of phagocytosis that were sevenfold greater than those of unincubated controls. Likewise, a tenfold increase occurred in incubated as opposed to unincubated RCS eyes, raising the possibility that phagocytosis could be experimentally stimulated in vivo.
Genetically Determined Sex-Reversal in 46,XY Humans
Authors: German James , Simpson Joe Leigh , Chaganti R. S. K. , Summitt Robert L. , Reid Lloyene Bruce , Merkatz Irwin R.
Published: October 2006

Evidence is presented for the existence of a gene, probably on the X chromosome, which prevents testis differentiation when present in 46,XY human embryos. Affected 46,XY women are not completely normal because of premature ovarian involution, as a result of which they have "streak gonads" similar to those of 45,X women.
Membrane Potential Changes During Chemokinesis in
Paramecium
Authors: Van Houten Judith
Published: October 2006

Intracellular recordings show that (i) paramecia hyperpolarize slightly in attractants and depolarize in repellents that depend on the avoiding reaction (an abrupt change of swimming direction), and (ii) paramecia more strongly hyperpolarize in repellents and more strongly depolarize in attractants that depend on changes of swimming velocity. These membrane potential changes are in agreement with a hypothesis of membrane potential control of chemokinesis in
Paramecium
.
Requirement for a Signal Sequence in Biological Expression of the v-
sis
Oncogene
Authors: Hannink Mark , Donoghue Daniel J.
Published: October 2006

The protein encoded by the simian sarcoma virus oncogene (v-
sis
) contains a signal sequence, derived from the envelope gene of the parental retrovirus, which is required for transformation. Removal of the proposed signal sequence was correlated with loss of biological activity. This activity was restored to inactive deletion mutants by fusion with the coding region for a heterologous signal sequence. Biological activity of v-
sis
was also abolished by either a small deletion within the coding region of the signal sequence or by a point mutation introduced by site-directed mutagenesis.
Bee Venom Enhances Guanylate Cyclase Activity
Authors: Vesely David L.
Published: October 2006

Bee venom and phospholipase A2 extracted from bee venom enhanced guanylate cyclase (E.C. 4.6.1.2) activity two- to threefold in rat liver, lung, heart, kidney, ileum, and cerebellum. Dose-response relationships revealed that bee venom at concentrations as low as 1 microgram per milliliter and phospholipase A2 at 1 microunit per milliliter caused a maximal enhancement of guanylate cyclase.
The Carboxy Terminus of the Precursor to Vasopressin and Neurophysin: Immunocytochemistry in Rat Brain
Authors: Watson Stanley J. , Seidah Nabil G. , Chrétien Michel
Published: October 2006

A pituitary glycopeptide whose amino acid sequence was previously identified has now been recognized as the final portion of the precursor to arginine vasopressin and its associated neurophysin. Immunocytochemical techniques with antiserums against this 39 amino acid peptide and vasopressin were used to study their distribution in the rat central nervous system. The peptide is located in vasopressin-synthesizing cells in the neurosecretory magnocellular nuclei. Positively stained fibers project from the magnocellular nuclei through the median eminence to the posterior pituitary. Studies of the homozygous Brattleboro rat, which is known to be deficient in the production of vasopressin and its related neurophysin, also show the absence of immunoreactivity to this peptide. These immunocytochemical data strongly indicate that the peptide is synthesized with vasopressin.
Adrenocorticotropic Hormone Causes Long-Lasting Potentiation of Transmitter Release from Frog Motor Nerve Terminals
Authors: Johnston Michael F. , Kravitz Edward A. , Meiri Halina , Rahamimoff Rami
Published: October 2006

Exposure of frog neuromuscular preparations to adrenocorticotropic hormone for several minutes increased both nerve-evoked and spontaneous transmitter release for several hours. No changes in postsynaptic sensitivity to transmitter were detected. The long-lasting potentiation shows little sensitivity to changes in extracellular calcium concentration and seems to be entirely presynaptic in origin.
Opioid Receptors Undergo Axonal Flow
Authors: Young W. Scott , Wamsley James K. , Zarbin Marco A. , Kuhar Michael J.
Published: October 2006

Previous studies have indicated the presence of opiate receptors on axons of the rat vagus nerve and on other small diameter fibers. In examinations of the effect of ligation on the distribution of receptors in the vagus nerve by in vitro labeling light microscopic autoradiography, a large buildup of receptors was found proximal to the ligature. This result indicates an axonal flow of receptors.
Release of Immunoreactive Serotonin into the Lumen of the Feline Gut in Response to Vagal Nerve Stimulation
Authors: Ahlman H. , DeMagistris L. , Zinner M. , Jaffe B. M.
Published: October 2006

Immunoreactive serotonin was detected in the lumen of the proximal jejunum of food-deprived cats. During perfusion of this intestinal segment in vivo, there was a constant basal rate of intraluminal secretion of this amine. The rate of secretion was significantly increased during efferent electrical stimulation of the cut cervical vagal nerves. This stimulatory effect was not altered after bilateral adrenalectomy was performed in the same animals. A synchronous release of substance P into the gut lumen was also demonstrated during vagal stimulation. During the period of increased intraluminal secretion of immunoreactive serotonin, there was no demonstrable change in the portal or systemic blood levels of this amine.
Substance P in Principal Sympathetic Neurons: Regulation by Impulse Activity
Authors: Kessler John A. , Adler Joshua E. , Bohn Martha C. , Black Ira B.
Published: October 2006

Regulation of the putative peptide neurotransmitter substance P was examined in the superior cervical sympathetic ganglion of the neonatal rat. Surgical decentralization (denervation) of the superior cervical ganglion increased ganglion substance P content. In cultured ganglia, the amount of substance P increased more than 50-fold after 48 hours, and this rise was dependent on protein and RNA synthesis. Veratridine prevented the increase in substance P in vitro, and tetrodotoxin blocked the veratridine effect; this suggests that sodium influx and membrane depolarization prevent substance P elevation. Immunohistochemical analysis of cultured ganglia indicated that substance P was present in the perikarya of principal sympathetic neurons and in ganglionic nerve processes. Transsynaptic impulses, through the mediation of postsynaptic sodium influx, may decrease substance P in sympathetic neurons.
Biplexiform Cells: Ganglion Cells of the Primate Retina That Contact Photoreceptors
Authors: Mariani Andrew P.
Published: October 2006

Golgi-impregnated biplexiform cells of the macaque retina are neurons with cell bodies in the ganglion cell layer, an axon in the nerve fiber layer, and dendrites in the inner plexiform layer that are postsynaptic to amacrine cell processes and bipolar cell axon terminals. In these features they resemble conventional ganglion cells, but they also have processes that arise from the main dendritic arborization, extend to the outer plexiform layer, and are postsynaptic to rod photoreceptor terminals as central elements at the ribbon synaptic complex. However, ordinary retinal ganglion cell dendrites ramify in the inner plexifrom layer and do not contact photoreceptors. Thus, biplexiform cells represent a previously undescribed class of neuron, part of whose synaptic input could bypass the commonly described interneuron circuitry of the vertebrate retina.
Substance P and Somatostatin Regulate Sympathetic Noradrenergic Function
Authors: Kessler John A. , Adler Joshua E. , Black Ira B.
Published: October 2006

Peptidergic-noradrenergic interactions were examined in explants of rat sympathetic superior cervical ganglia and in cultures of dissociated cells. The putative peptide transmitters substance P and somatostatin each increased the activity of the catecholamine-synthesizing enzyme tyrosine hydroxylase after 1 week of exposure in culture. Maximal increases occurred at 10
-7
molar for each peptide, and either increasing or decreasing the concentration reduced the effects. Similar increases in tyrosine hydroxylase were produced by a metabolically stable agonist of substance P, while a substance P antagonist prevented the effects of the agonist. The data suggest that the increased tyrosine hydroxylase activity was mediated by peptide interaction with specific substance P receptors and that peptides may modulate sympathetic catecholaminergic function.
Neuron-Glia Adhesion Is Inhibited by Antibodies to Neural Determinants
Authors: Grumet M. , Rutishauser U. , Edelman G. M.
Published: October 2006

Suspensions of embryonic chick neuronal cells adhered to monolayers of glial cells, but few neurons bound to control monolayers of fibroblastic cells from meninges or skin. Neuronal cell-glial cell adhesion was inhibited by prior incubation of the neurons with Fab′ fragments of antibodies to neuronal membranes. In contrast, antibodies to the neural cell adhesion molecule (N-CAM) did not inhibit the binding. These results suggest that a specific adhesive mechanism between neurons and glial cells exists and that it is mediated by CAM's that differ from those so far identified.
Spinal Fluid Differences in Experimental Allergic Encephalomyelitis and Multiple Sclerosis
Authors: Gutstein H. S. , Cohen S. R.
Published: October 2006

The spinal fluid of sheep with experimental allergic encephalomyelitis contains myelin basic protein (6 to 18 nanograms per milliliter) bound to antibody as well as excess free antibody. This bound myelin basic protein appeared concurrently with the onset of the disease and remained elevated until death. In contrast, in active multiple sclerosis, the spinal fluid contains free myelin basic protein and there are no detectable levels of antibody. The results indicate that the antibodies enter the spinal fluid from the serum by passive diffusion. This mechanism may also explain the presence of viral antibodies in the spinal fluid of multiple sclerosis patients.
A Replication Cycle for Viroids and Other Small Infectious RNA's
Authors: Branch Andrea D. , Robertson Hugh D.
Published: October 2006

Experimental data concerning viroid-specific nucleic acids accumulating in tomato plants establish, together with earlier studies, the major features of a replication cycle for viroid RNA in plant cells. Many features of this pathway, which involves multimeric strands of both polarities, may be shared by other small infectious RNA's including certain satellite RNA's and "virusoid" RNA's which replicate in conjunction with conventional plant viruses. The presence, in host plants, of an elaborate machinery for replicating these disease agents suggests a role for endogenous small RNA's in cellular development.
Phorbol Ester Action Is Independent of Viral and Cellular
src
Kinase Levels
Authors: Goldberg Allan R. , Delclos K. Barry , Blumberg Peter M.
Published: October 2006

Treatment of normal chick embryo fibroblasts with phorbol myristate acetate causes those cells to express many of the phenotypic properties of virally transformed cells and also enhances the expression of transformed properties in Rous sarcoma virus-transformed chick embryo fibroblasts. We report here that phorbol myristate acetate has little or no effect on the level of protein kinases encoded by the viral src or endogenous sarc genes.
Pro-Adrenocorticotropin/Endorphin-Derived Peptides: Coordinate Action on Adrenal Steroidogenesis
Authors: Pedersen Robert C. , Brownie Alexander C. , Ling Nicholas
Published: October 2006

A synthetic peptide, representing a portion of the 16K (16,000 dalton)-fragment sequence within the pro-adrenocorticotropin/endorphin precursor molecule, potentiates the steroidogenic action of the 1 to 24 portion of adrenocorticotropin [ACTH(1-24)] on the rat adrenal cortex. The peptide has 27 amino acid residues and consists of γ-melanotropin with a carboxyl terminal extension. It affects both the inner and outer adrenocortical zones of hypophysectomized animals, as evidenced by a synergistic augmentation of corticosterone and aldosterone production, respectively. The peptide can be distinguished from adrenocorticotropin by its activation of cholesterol ester hydrolase and its failure to stimulate cholesterol side-chain cleavage.
1α,25-Dihydroxyvitamin D
3
Nuclear Receptors in Pituitary
Authors: Gelbard Harris A. , Stern Paula H. , U'Prichard David C.
Published: October 2006

Specific binding of 1α,25-dihydroxyvitamin D
3
was found in nuclear and cytosol fractions of the bovine pituitary. For nuclear binding. the dissociation constant was 0.1 nanomole per liter, and maximum binding was 104 femtomoles per milligram of protein. In competition studies, 25-hydroxyvitamin D
3
was 300 times weaker than 1α,25-dihydroxyvitamin D
3
. The existence of high-affinity sites supports a physiologic role for 1α,25-dihydroxyvitamin D
3
in the pituitary.
Prostaglandins, Arachidonic Acid, and Inflammation
Authors: Kuehl Frederick A. , Egan Robert W.
Published: October 2006

The enzymatic oxidation of arachidonic acid has been shown to yield potent pathological agents by two major pathways. Those of the prostaglandin (PG) pathway, particularly PGE2, have been implicated as inflammatory mediators for many years. The discovery and biological activities of thromboxane A2and prostacyclin as well as a destructive oxygen-centered radical as additional products of this biosynthetic pathway now require these to be considered as potential inflammatory mediators. Like PGE2, their biosynthesis is prevented by nonsteroidal anti-inflammatory agents. More recently, the alternative metabolic route, the lipoxygenase pathway, has been shown to yield a new class of arachidonic acid oxygenation products, called the leukotrienes, which also appear to be important inflammatory mediators. Unlike the prostaglandins, some of which play important roles as biological regulators, the actions of the lipoxygenase products appear to be exclusively of a pathological nature.
Transformation by Cloned Harvey Murine Sarcoma Virus DNA: Efficiency Increased by Long Terminal Repeat DNA
Authors: Chang Esther H. , Ellis Ronald W. , Scolnick Edward M. , Lowy Douglas R.
Published: October 2006

The coding sequences for the transforming (
src
) protein (p21) of Harvey murine sarcoma virus have been localized to a 1.3-kilobase pair segment near the 5′ end of the viral genome. Ligation of the viral long terminal repeat DNA to the left end of the
src
region DNA markedly enhanced the low transforming efficiency of the
src
region DNA.
Fasting Associated with Decrease in Hypothalamic β-Endorphin
Authors: Gambert Steven R. , Garthwaite Thomas L. , Pontzer Carol H. , Hagen Thad C.
Published: October 2006

In rats that were fasted for 2 to 3 days there was a decline in hypothalamic, but not pituitary, β-endorphin. There was no change in pituitary or hypothalamic adrenocorticotropin content as a result of fasting. Endogenous opiates may be involved in physiological adaptation to fasting.
Transmitter Sensitivity of Neurons Assayed by Autoradiography
Authors: Yoshikami Doju
Published: October 2006

Ionic conductance channels that are opened by activating nicotinic acetylcholine receptors at synapses of sympathetic neurons are permeable to small organic amines. Uptake of a tritium-labeled amine through these channels can be measured by autoradiography. This provides a simple and direct way to assess the sensitivity of individual neurons to acetylcholine without using microelectrodes.
Δ
9
-Tetrahydrocannabinol Increase Plasma Testosterone Concentrations in Mice
Authors: Dalterio Susan , Bartke Andrzej , Mayfield Denise
Published: October 2006

Oral administration of Δ
9
-tetrahydrocannabinol had a biphasic effect on plasma testosterone concentrations in male mice, causing rapid sustained increases at low doses and subsequent decreases at higher doses. In hypophysectomized and intact mice receiving gonadotropins (human chorionic gonadotropin), treatment with Δ
9
-tetrahydrocannabinol maintained higher plasma testosterone concentrations. Thus, this cannabinoid may interact with gonadotropin and directly influence testicular steroidogenesis in vivo.
Polymorphism in the 5′-Flanking Region of the Human Insulin Gene and Its Possible Relation to Type 2 Diabetes
Authors: Rotwein Peter , Chyn Rose , Chirgwin John , Cordell Barbara , Goodman Howard M. , Permut M. Alan
Published: October 2006

The arrangement of the human insulin gene in DNA from 87 individuals was analyzed by the Southern blot hybridization technique with a cloned genomic human insulin probe. Insertions of 1.5 to 3.4 kilobase pairs in the 5′-flanking region of the gene were found in DNA from 38 individuals. These insertions occurred within 1.3 kilobase pairs of the transcription initiation site. In contrast, no insertions were observed in the region 3′ to the coding sequence. The prevalence of these insertions in type 2 diabetes was significantly greater than in the other groups (P < .001). The limitation of this striking length polymorphism to a potential promoter region suggests that these insertions may play a role in insulin gene expression.
Corticotropin-Releasing Activity of α-Melanotropin
Authors: Lis Martin , Julesz Janos , Gutkowska Jolanta , Genest Jacques
Published: October 2006

Synthetic α-melanotropin stimulated the release of immunoreactive adrenocorticotropin from primary cultures of rat anterior pituitary cells. The effect of the α-melanotropin was dose-dependent. Cells incubated with synthetic arginine-vasopressin and α-melanotropin simultaneously produced an amount of adrenocorticotropin that was greater than the sum of the amount that the cells produced in response to each peptide added separately. Other peptides structurally similar to α-melanotropin, such as, β-, γ
1
-, γ
2
-, and γ
2
-melanotropin, were also tested for adrenocorticotropin-releasing activity. Only the γ
2
-melanotropin demonstrated a statistically significant effect. A vasopressin preparation (Pitressin, Parke-Davis) purified from posterior pituitaries and previously shown to contain some α-melanotropin was much more potent in releasing adrenocorticotropin than the synthetic vasopressin.
Isolation of Infectious Bovine Rhinotracheitis Virus from the Soft-Shelled Tick,
Ornithodoros coriaceus
Authors: Taylor Robert E. L. , Seal Bruce S. , St Jeor Stephen
Published: October 2006

Infectious bovine rhinotracheitis virus was isolated from the soft-shelled tick (
Ornithodoros coriaceus
). Serological identification of the isolated viruses was confirmed by restriction endonuclease digestion of purified virus DNA. These isolations indicate that the soft-shelled tick may be a vector for infectious bovine rhinotracheitis virus. This may be the first reported isolation of a mammalian herpesvirus from an arthropod vector.
Inhibition of Adrenocorticotropic Hormone Secretion in the Rat by Immunoneutralization of Corticotropin-Releasing Factor
Authors: Rivier Catherine , Rivier Jean , Vale Wylie
Published: October 2006

Intravenous administration of rabbit antiserum to ovine corticotropin-releasing factor (CRF) markedly reduced the CRF-induced rise of plasma adrenocorticotropic hormone (ACTH) in intact nonstressed adult male rats while blocking more than 75 percent of the ACTH release observed in rats exposed to ether stress. Furthermore, antiserum to CRF significantly lowered ACTH levels in adrenalectomized animals. These results suggest that endogenous CRF plays a physiological role in regulating ACTH secretion.
Chromosomal Assignment of the Endogenous Proto-Oncogene C-
abl
Authors: Goff Stephen P. , D'Eustachio Peter , Ruddle Frank H. , Baltimore David
Published: October 2006

Abelson murine leukemia virus (A-MuLV) is a replication-defective retrovirus that transforms lymphocytes of the B-cell lineage. This virus is a recombinant between the parental Moloney murine leukemia virus and a cellular gene termed C-
abl
. By analysis of a series of mouse × Chinese hamster hybrid cell lines containing various mouse chromosomes, we have mapped the C-
abl
gene to mouse chromosome 2.
Dimethyl Sulfoxide Stimulates Tyrosine Residue Phosphorylation of Rat Liver Epidermal Growth Factor Receptor
Authors: Rubin Richard A. , Earp H. Shelton
Published: October 2006

Epidermal growth factor, a potent mitogen, stimulates phosphorylation of its 170,000-dalton plasma membrane receptor. Dimethyl sulfoxide selectively increased phosphorylation of the epidermal growth factor receptor in rat liver microsomal fraction. Maximal stimulation occurred at 15 to 25 percent dimethyl sulfoxide and resembled the effect of epidermal growth factor in magnitude and rapidity. Like epidermal growth factor, dimethyl sulfoxide selectively stimulated tyrosine residue phosphorylation of this protein.
Prospects in Plant Genetic Engineering
Authors: Barton Kenneth A. , Brill Winston J.
Published: October 2006

The functional expression of a novel gene in a genetically engineered plant has not yet been reported. One major barrier in movement toward this goal is our limited understanding of the molecular bases of gene expression. Attempts to establish genetic engineering as a practical facet of plant breeding are also complicated by the fact that genes for most important plant characteristics have not yet been identified. However, the benefits to be gained from all aspects of plant improvement are stimulating research into both the development of plant transformation technology and the isolation and characterization of genes responsible for valuable traits. As scientists develop greater knowledge of plant molecular genetics, we can expect to see practical applications in such diverse areas as improvement of plant nutritional quality, decreases in fertilization requirements, and increases in resistance to environmental stresses and pathogens.
Methadone Conformation and Opioid Activity
Authors: Duax William L. , Smith G. David , Griffin Jane F. , Portoghese P. S.
Published: October 2006

The inactive methadone analog
threo
-5-methylmethadone has a solid-state conformation in which the nitrogen is antiperiplanar to the tertiary carbon C(4). Since
threo
-5-methylmethadone exhibits no opioid agonism either in vivo or in vitro, methadone analogs probably do not have this conformation when bound to an opioid receptor. The potent agonist (-)-
erythro
-5-methylmethadone has a solid-state conformation in which the nitrogen atom is rotated back toward the phenyl rings on the quarternary carbon, suggesting that this unusual conformation is the active one.
RNA Splice Site Selection: Evidence for a 5′ → 3′ Scanning Model
Authors: Lang Katharine M. , Spritz Richard A.
Published: October 2006

Human G
γ
-globin genes containing tandem duplications of the donor (5′) or acceptor (3′) RNA splice sites of the second intervening sequence were constructed in order to ascertain the directionality of RNA splice site selection. These genes were introduced into cultured monkey cells, and their transcripts were analyzed. Transcripts of these duplication variants were spliced only at the proximal copy of the duplicated splice sites. These data are consistent with a 5′→3′ model of splice site selection.
Epstein-Barr Virus: Inhibition of Replication by Three New Drugs
Authors: Lin Jung-Chung , Smith M. Carolyn , Cheng Yung-Chi , Pagano Joseph S.
Published: October 2006

Epstein-Barr virus (EBV) is the cause of infectious mononucleosis and is associated with three human malignancies. Acyclovir [9-(2-hydroxyethoxymethyl)guanine], the first clinically useful drug effective against replication of EBV, is without effect against latent or persistent EBV infection. Three nucleoside analogs, E-5-(2-bromovinyl)-2′-deoxyuridine, 1-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-5-iodocytosine, and 1-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-5-methyluracil are potent inhibitors of EBV replication in vitro. Moreover, in contrast to the reversibility of viral inhibition by Acyclovir, these three drugs have prolonged effects in suppressing viral replication even after the drugs are removed from persistently infected cell cultures.
DNA-Binding Proteins
Authors: Takeda Y. , Ohlendorf D. H. , Anderson W. F. , Matthews B. W.
Published: October 2006

The structures of three proteins that regulate gene expression have been determined recently and suggest how these proteins may bind to their specific recognition sites on the DNA. One protein (Cro) is a repressor of gene expression, the second (CAP) usually stimulates gene expression, and the third (lambda repressor) can act as either a repressor or an activator. The three proteins contain a substructure consisting of two consecutive alpha helices that is virtually identical in each case. Structural and amino acid sequence comparisons suggest that this bihelical fold occurs in a number of proteins that regulate gene expression, and is an intrinsic part of the DNA-protein recognition event. The modes of repression and activation by Cro and lambda repressor are understood reasonably well, but the mode of action of CAP is still unclear.
Total Synthesis and Cloning of a Gene Coding for the Ribonuclease S Protein
Authors: Nambiar Krishnan P. , Stackhouse Joseph , Stauffer Dora M. , Kennedy W. Poindexter , Eldredge J. K. , Benner Steven A.
Published: October 2006

A gene for ribonuclease S protein, has been chemically synthesized and cloned. The gene is designed to have 25 specific restriction endonuclease sites spaced at short intervals, permitting its structure to be rapidly modified. This flexibility facilitates tests of hypotheses relating the primary structure of the enzyme to its physical and catalytic behavior.
Nucleotide Sequence of a Human
Blym
Transforming Gene Activated in a Burkitt's Lymphoma
Authors: Diamond Alan , Devine Joan M. , Cooper Geoffrey M.
Published: October 2006

The nucleotide sequence of a human
Blym
-1 transforming gene activated in a Burkitt's lymphoma cell line was determined. This sequence predicts a small protein of 58 amino acids that is 33 percent identical to the predicted product of chicken
Blym
-1, the activated transforming gene of chicken B cell lymphomas. Both the human and chicken
Blym
-1 genes exhibit significant identity to an amino-terminal region of transferrins.
Homologous Recombination Catalyzed by Mammalian Cell Extracts in Vitro
Authors: Darby V. , Blattner F.
Published: October 2006

An assay was developed to detect recombination events taking place in an in vitro reaction. Extracts of cultured mouse preB lymphocytes were found to catalyze homologous recombination between substrate DNA molecules but not site-specific recombination between cloned mouse immunoglobulin D and J genes. Addition of deoxyribonucleoside triphosphates increased the frequency of homologous recombination. This recombination activity was not observed in two differentiated lymphocyte cell lines.
Insulin Receptor Antiserum and Plant Lectins Mimic the Direct Effects of Insulin on Nuclear Envelope Phosphorylation
Authors: Purrello Francesco , Burnham Daniel B. , Goldfine Ira D.
Published: October 2006

Insulin directly inhibits protein phosphorylation in isolated rat liver nuclear envelopes. In the present studies, an antiserum to insulin receptor as well as the plant lectins concanavalin A and phytohemagglutinin mimicked insulin action in isolated nuclear envelopes. These studies suggest that insulin and agents that mimic it may directly regulate nuclear functions.
Muscular Dystrophy: Inhibition of Degeneration in Vivo with Protease Inhibitors
Authors: Stracher A. , McGowan E. B. , Shafiq S. A.
Published: October 2006

The protease inhibitors leupeptin and pepstatin were used in vivo in genetically dystrophic chickens to determine their effects on the histological and biochemical changes observed in this disease. These compounds appear to delay the degeneration of muscle tissue which is characteristic of this disorder and thus may have potential therapeutic value in the treatment of muscular dystrophy.
Waterlogged Molecules
Authors: Wolfenden Richard
Published: October 2006

Measurements of vapor pressures over their aqueous solutions indicate that organic compounds show profound differences in hydrophilic character. These differences are of such magnitude as to suggest an important role for changing solvation in determining free energy changes associated with metabolic transformations in water, and in governing structural equilibria of proteins and other large molecules in water. When two or more functional groups are present within the same solute molecule, their combined effects on its free energy of solvation are commonly additive. Striking departures from additivity, observed in certain cases, indicate the existence of special interactions between different parts of a solute molecule and the water that surrounds it. Similar considerations presumably apply to activated intermediates in the interconversion of biological materials.
Adenovirus E1a Gene Product Expressed at High Levels in
Escherichia coli
Is Functional
Authors: Ferguson Blair , Jones Nicholas , Richter Joel , Rosenberg Martin
Published: October 2006

The human type C adenovirus E1a 13
S
messenger RNA encodes a gene product, that positively regulates the transcription of viral genes and certain cellular genes and is involved in the transformation of primary mammalian cells. The E1a gene product was expressed at high levels in Escherichia coli. In a
Xenopus
oocyte microinjection assay, the purified
Escherichia coli
-produced protein activated the E1a-responsive adenovirus E3 promoter and functioned as efficiently as the E1a gene itself.
Laser Chemical Analysis
Authors: Zare Richard N.
Published: October 2006

Selected applications of laser methods to analytical problems are reviewed. Examples are chosen from multiphoton ionization and laser fluorescence analysis. Although efforts to carry out elemental analysis with laser techniques are probably the most advanced, studies suggest that the analysis of molecular species is also quite promising, particularly in regard to interfacing laser fluorimetric detection with high-performance liquid chromatography. Recent experiments indicate that analysts can expect to attain in a number of cases the ultimate limit of single-atom or single-molecule detection with laser-based methods.
Contemporary Methodology for Protein Structure Determination
Authors: Hunkapiller Michael W. , Strickler James E. , Wilson Kenneth J.
Published: October 2006

The techniques used for the characterization of protein and peptide structure have undergone great changes that have improved the speed, reliability, and applicability of the process. High-performance liquid chromatography and gel electrophoresis have made the purification of proteins and peptides a routine procedure, even when the compound of interest is a minor component of a complex biological mixture. The chemistry and instrumentation used in amino acid analysis and amino acid sequencing now permit the analysis of as little as 5 to 50 picomoles of samples. This represents an increase in sensitivity of more than a thousandfold over the last 10 years and has made possible the structural analysis of a wide variety of scarce but important compounds.
Increased Chromosomal Mutation Rate After Hybridization Between Two Subspecies of Grasshoppers
Authors: Shaw D. D. , Wilkinson P. , Coates D. J.
Published: October 2006

Hybridization between two chromosomally distinct subspecies of the grasshopper
Caledia captiva
results in a high incidence of novel chromosomal rearrangements among the backcross progeny. Rearrangements are restricted to those chromosomes derived from the F
1
hybrid parent. Chromosomal involvement is nonrandom with the same rearrangement occurring repeatedly in different backcrosses. A single individual can also generate an array of different rearrangements among its offspring. Several of the rearrangements have also been found in natural populations. The nonrandom and recurrent nature of these chromosomal mutations at high frequencies provides a plausible explanation for the establishment and fixation of chromosomal rearrangements in natural populations.
Depletion of Intracellular Polyamines May Alter DNA Conformation in 9L Rat Brain Tumor Cells
Authors: Hung David T. , Marton Laurence J. , Deen Dennis F. , Shafer Richard H.
Published: October 2006

Depletion of polyamines in 9L rat brain tumor cells by treatment with α-difluoromethylornithine dramatically altered DNA conformation as measured by viscoelastometry. The reduction of intracellular putrescine and spermidine concentrations to less than 5 percent of their concentrations in control cells decreased the sensitivity of 9L cell DNA to x-irradiation and increased the maximum viscoelastic retardation time of the DNA. Both of these phenomena were reversed by addition of exogenous putrescine.
Fiber-Optic Sensors for Biomedical Applications
Authors: Peterson John I. , Vurek Gerald G.
Published: October 2006

In this article the development of fiber-optic sensors for biomedical applications is reviewed. Light-carrying fibers are potentially useful in oximetry, dye dilution measurements, laser-Doppler velocimetry, and fluorometry; as physical sensors of temperature, pressure, and radiation; and as chemical sensors of
p
H, partial pressure of blood gases, and glucose. Emphasis is placed on the principles and ideas used in the various devices rather than on detailed descriptions or critical discussions.
A New Ribosome Structure
Authors: Henderson Eric , Oakes Melanie , Clark Michael W. , Lake James A. , Matheson A. T. , Zillig W.
Published: October 2006

Ribosomes derived from the sulfur-dependent archaebacteria are structurally distinct from those types found in ribosomes from eubacteria, eukaryotes, and other archaebacteria. All four ribosome types share a common structural core, but each type also has additional independent structural features. In the smaller subunit derived from sulfur-dependent archaebacteria ("eocytes"), lobes, similar to those found at the base of the eukaryotic small subunits, and an archaebacterial bill, similar to those found on the smaller subunit of archaebacteria and eukaryotes, are present. On the larger subunit from sulfur-dependent archaebacteria, an eocytic lobe, eocytic gap, and eocytic bulge are present. These features, with the exception of the eocytic gap, are found in a slightly modified form on eukaryotic large subunits. These novel ribosomal properties are in general consistent with other molecular biological properties peculiar to these organisms.
Studying Enzyme Mechanism by
13
C Nuclear Magnetic Resonance
Authors: Mackenzie Neil E. , Malthouse J. Paul G. , Scott A. I.
Published: October 2006

High-resolution carbon-13 nuclear magnetic resonance (NMR) spectra of enzyme-inhibitor and enzyme-substrate complexes provide detailed structural and stereochemical information on the mechanism of enzyme action. The proteases trypsin and papain are shown to form tetrahedrally coordinated complexes and acyl derivatives with a variety of compounds artificially enriched at the site or sites of interest. These results are compared with the structural information derived from x-ray diffraction. Detailed NMR studies have provided a clearer picture of the ionization state of the residues participating in enzyme-catalyzed processes than other more classical techniques. The dynamics of enzymic catalysis can be observed at sub-zero temperatures by a combination of cryoenzymology and carbon-13 NMR spectroscopy. With these powerful techniques, transient, covalently bound intermediates in enzyme-catalyzed reactions can be detected and their structures rigorously assigned.
Transfection of the DNA Polymerase-α Gene
Authors: Liu Philip K. , Loeb Lawrence A.
Published: October 2006

DNA polymerase-α is the major replicative DNA polymerase in animal cells. The gene coding for a mutant DNA polymerase-α was transferred from one cell to another by transfection of DNA from mutant cells. The DNA was isolated from a mutant hamster cell line resistant to aphidicolin, a specific inhibitor of DNA polymerase-α, and transferred into an aphidicolin-sensitive cell line. The resulting transfectants exhibited increased survival in the presence of aphidicolin and contained an aphidicolin-resistant DNA polymerase-α.
Tumor Promoters Inhibit Morphological Differentiation in Cultured Mouse Neuroblastoma Cells
Authors: Ishii Douglas N. , Fibach Eitan , Yamasaki Hiroshi , Weinstein I. Bernard
Published: October 2006

When added to mouse neuroblastoma cultures, the potent tumor promoter 12-
O
-tetradecanoyl-phorbol-13-acetate (TPA) inhibits spontaneous neurite formation as well as that induced in response to serum deprivation, prostaglandin E
1
, 5-bromo-2′-deoxyuridine, and papaverine. Other tumor-promoting macrocyclic plant diterpenes also inhibit neurite formation, whereas nonpromoting diterpenes do not. Inhibition by TPA was reversible and was unrelated to toxicity.
Identified Interneurons Produce Both Primary Afferent Depolarization and Presynaptic Inhibition
Authors: Kirk Mark D. , Wine Jeffrey J.
Published: October 2006

Crayfish interneurons were identified that appear to be directly responsible for presynaptic inhibition of primary afferent synapses during crayfish escape behavior. The interneurons are fired by a polysynaptic pathway triggered by the giant escape command axons. When directly stimulated, these interneurons produce short-latency, chloride-dependent primary afferent depolarizations and presynaptically inhibit primary afferent input to mechanosensory interneurons.
A Novel Nuclear Form of Estradiol Receptor in MCF-7 Human Breast Cancer Cells
Authors: Kasid Attan , Strobl Jeannine S. , Huff Karen , Greene Geoffrey L. , Lippman Marc E.
Published: October 2006

Nuclear estrogen receptor from MCF-7 cells undergoes a time-dependent, hormone-inducible transformation to a form that is less extractable from nuclei and less exchangeable with ligand. This receptor-modifying, intranuclear event is independent of receptor loss (processing) and appears associated with hormone responsiveness (progesterone-receptor induction) in these cells. The magnitude of receptor loss, however, is variable and apparently not a prerequisite for hormone action to induce progesterone receptor.
Human Ornithine Transcarbamylase Locus Mapped to Band Xp21.1 Near the Duchenne Muscular Dystrophy Locus
Authors: Lindgren Valerie , de Martinville Bérengère , Horwich Arthur L. , Rosenberg Leon E. , Francke Uta
Published: October 2006

The gene for the mitochondrial enzyme ornithine transcarbamylase was mapped to the short arm of the X chromosome by in situ hybridization experiments, with DNA complementary to the human ornithine transcarbamylase gene used as a probe. A series of cell lines with X chromosome abnormalities was used to localize the gene to band Xp21.1. Because the gene maps near the Duchenne muscular dystrophy locus, the ornithine transcarbamylase probe may be useful in carrier detection and prenatal diagnosis of Duchenne muscular dystrophy as well as of ornithine transcarbamylase deficiency.
Synthesis of a Cyclic Melanotropic Peptide Exhibiting Both Melanin-Concentrating and -Dispersing Activities
Authors: Wilkes Brian C. , Hruby Victor J. , de L. Castrucci A. M. , Sherbrooke Wade C. , Hadley Mac E.
Published: October 2006

A putative melanin-concentrating hormone was synthesized. This peptide, H-Asp-Thr-Met-Arg-Cys-Met-Val-Gly-Arg-Val-Tyr-Arg-Pro-Cys-Trp-Glu-Val-OH, stimulates melanin granule aggregation within teleost melanocytes at nanomolar concentrations as does the natural purified teleost pituitary preparation. In addition, this peptide stimulates melanin granule dispersion within melanocytes of frogs and lizards. The peptide has about one six-hundredth of the activity of α-melanocyte-stimulating hormone on frog and lizard melanocytes and is a full agonist.
1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine Destroys Dopamine Neurons in Explants of Rat Embryo Mesencephalon
Authors: Mytilineou Catherine , Cohen Gerald
Published: October 2006

Explants of embryonic rat mesencephalon were grown in organotypic culture. Addition of 10 μ
M
1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to the culture medium for 4 to 7 days resulted in loss of dopamine cell bodies and fiber outgrowths, as observed by fluorescence histochemistry. At the same time, the cultures showed decreased uptake of tritium-labeled dopamine. However, no signs of generalized toxicity were evident when the explant cultures were viewed by light and phase-contrast microscopy. These results show that MPTP exerts a relatively selective destructive action in dopamine neurons in vitro, similar to the action observed in humans and monkeys in vivo. Pargyline (10 μ
M
), a monoamine oxidase inhibitor, protected the dopamine neurons in the explants. Organotypic cultures provide an experimental model for the study of the properties of MPTP in vitro.
Activation of Central Neurons by Ventral Root Afferents
Authors: Chung J. M. , Lee K. H. , Endo K. , Coggeshall R. E.
Published: October 2006

It is a fundamental principle of vertebrate neuronal organization that sensory fibers are restricted to dorsal roots and motor fibers to ventral roots. Recent evidence, however, indicates that there are many sensory fibers in ventral roots. The present report shows that stimulation of these fibers activates neurons in the dorsal horn. This provides evidence at the single-cell level for the importance of ventral root afferents and provides an explanation for the clinical phenomenon of recurrent sensibility.
Thrombin-Induced Platelet Aggregation Is Mediated by a Platelet Plasma Membrane-Bound Lectin
Authors: Gartner T. Kent , Williams Danny C. , Minion Frank C. , Phillips David R.
Published: October 2006

Thrombin-activated human platelets cause agglutination of trypsinized, formalinized bovine erythrocytes. This lectin activity of stimulated platelets was blocked by galactosamine, glucosamine, mannosamine, lysine, and arginine, but not by
N
-acetylated sugars, other neutral sugars, or other amino acids. Inhibitors of the thrombin-induced lectin activity also blocked thrombin-induced platelet aggregation. It appears that a membrane surface component that has lectin activity mediates platelet aggregation.
Learned Taste Aversions in Children Receiving Chemotherapy
Authors: Bernstein Ilene L.
Published: October 2006

Children with neoplastic diseases were offered an unusual ice cream before their drug treatments. Patients experiencing gastrointestinal toxicity due to the drugs were subsequently less likely to choose that ice cream again than controls. This suggests that taste aversions induced by drug-associated symptoms may contribute to the appetite loss experienced by cancer patients.
Medial Preoptic Lesions and Male Sexual Behavior: Age and Environmental Interactions
Authors: Twiggs Dennis G. , Popolow Herbert B. , Gerall Arnold A.
Published: October 2006

In all species studied, the medial preoptic area has been found to be necessary for male copulatory behavior. No recovery of sexual function from the medial preoptic area lesions appears to have been reported. This study demonstrates that rats with large lesions of the medial preoptic area exhibit adult male sexual behavior when the surgery is performed prepuberally and the rats have interacted socially with peers.
Limits to Growth in World Food Production
Authors: Jensen NF
Published: October 2006

The dramatic increases in wheat yields that began in the mid-1930's in the United States will soon begin to level off. The favorable mix of genetics and technology that has characterized this era must build upon an ever higher yield base for the future. At the same time the residue of factors that can lower wheat yields includes a larger proportion of forces not easily shaped or controlled by man. An example is weather. The result is a natural yield ceiling that is already visible and that will impose a limit on future productivity growth.
Red Cell Membrane Glycophorin Labeling from Within the Lipid Bilayer
Authors: Kahane Itzhak , Gitler Carlos
Published: October 2006

Human red blood cell membranes were labeled from within the lipid bilayer by the apolar photosensitive reagent, 5-[
125
I]iodonaphthyl-1-azide. Glycophorin, the major sialoglycoprotein of the red cell membrane, was purified by two different methods; it contained approximately half of the total label incorporated into membrane proteins. The label was confined to the trypsin-insoluble peptide of glycophorin that includes a sequence of 20, mainly apolar, amino acids. These findings provide direct evidence that the labeled segment resides within the membrane in direct contact with the lipid bilayer, and support the suggestion that glycophorin spans the bilayer through its hydrophobic domain.
Yolk Pigments of the Mexican Leaf Frog
Authors: Marinetti Guido V. , Bagnara Joseph T.
Published: October 2006

Eggs of the Mexican leaf frog contain blue and yellow pigments identified as biliverdin and lutein, respectively. Both pigments are bound to proteins that occur in crystalline form in the yolk platelet. The major blue pigment is biliverdin IXα. The eggs vary in color from brilliant blue to pale yellow-green depending on the amount of each pigment. These pigments may provide protective coloration to the eggs.