bluuebunny/crossref_metadata_2025 huggingface dataset:
Cross-Linked Fibrinogen Dimers Demonstrate a Feature of the Molecular Packing in Fibrin Fibers
Authors: Fowler W. E. , Erickson H. P. , Hantgan R. R. , McDonagh J. , Hermans J.
Published: October 2006

A stable population of fibrinogen dimers cross-linked by Factor XIIIa has been prepared and examined in the electron microscope. The trinodular fibrinogen molecules are cross-linked through their outer nodules in an end-to-end, non-overlapping fashion. These dimers form normal banded fibers after treatment with the clotting enzyme, thrombin.
Human T Cell Antigen Expression by Primate T Cells
Authors: Haynes Barton F. , Dowell Barry L. , Hensley Lucinda L. , Gore Ira , Metzgar Richard S.
Published: October 2006

Phylogenetic study in primates of the reactivity of 11 monoclonal antibodies to human T cells and rosette formation in the reaction of primate T cells with sheep erythrocytes demonstrate that the sheep erythrocyte receptor and the determinants of T cell subset antigens are highly conserved during primate evolution. Other T cell antigen determinants are less well conserved. Human, gorilla, and chimpanzee T cells showed identical reactivity with the monoclonal antibodies to human T cells. The expression of human T cell antigen determinants by primate T cells suggests a constant rate of evolution for this group of molecules and provides additional evidence that man and African apes shared a relatively recent common ancestor.
Serological Analysis of a Subgroup of Human T-Lymphotropic Retroviruses (HTLV-III) Associated with AIDS
Authors: Schüpbach Jörg , Popovic Mikulas , Gilden Raymond V. , Gonda Matthew A. , Sarngadharan M. G. , Gallo Robert C.
Published: October 2006

The two main subgroups of the family of human T-lymphotropic retroviruses (HTLV) that have previously been characterized are known as HTLV-I and HTLV-II. Both are associated with certain human leukemias and lymphomas. Cell surface antigens (p61 and p65) encoded by HTLV-I are frequently recognized, at low titers, by antibodies in the serum of patients with acquired immunodeficiency syndrome (AIDS) or with signs or symptoms that precede AIDS (pre-AIDS). This suggests an involvement of HTLV in these disorders. Another subgroup of HTLV, designated HTLV-III, has now been isolated from many patients with AIDS and pre-AIDS. In the studies described in this report, virus-associated antigens in T-cell clones permanently producing HTLV-III were subjected to biochemical and immunological analyses. Antigens of HTLV-III, specifically detected by antibodies in serum from AIDS or pre-AIDS patients and revealed by the Western blot technique, are similar in size to those found in other subgroups of HTLV. They include at least three serologically unrelated antigenic groups, one of which is associated with group-specific antigens (p55 and p24) and another with envelope-related (p65) proteins, while the antigens in the third group are of unknown affiliation. The data show that HTLV-III is clearly distinguishable from HTLV-I and HTLV-II but is also significantly related to both viruses. HTLV-III is thus a true member of the HTLV family.
Calcitonin Messenger RNA Encodes Multiple Polypeptides in a Single Precursor
Authors: Jacobs J. W. , Goodman R. H. , Chin W. W. , Dee P. C. , Habener J. F. , Bell N. H. , Potts J. T.
Published: October 2006

Recombinant DNA techniques were used to analyze the structure of the messenger RNA encoding a precursor of calcitonin, a small calcium-regulating hormone of 32 amino acids. Analyses of the nucleotide sequences of cloned complementary DNA's comprising the entire coding sequence of the messenger RNA revealed that calcitonin is flanked at both its amino and carboxyl termini by peptide extensions linked to the hormone by short sequences of basic amino acids. The location of glycine next to the carboxyl terminal prolinamide of calcitonin is consistent with indications that glycine is required for the enzymatic amidation of proline to the prolinamide. During cellular biosynthesis, calcitonin arises from a large precursor protein by cleavages at both amino and carboxyl terminal residues of the hormone. These findings raise questions concerning the regulation of these cleavages and the potential biological functions of the precursor extensions derived from these cleavages.
Nucleotide Sequence of the Oncogene Encoding the p21 Transforming Protein of Kirsten Murine Sarcoma Virus
Authors: Tsuchida Nobuo , Ryder Tom , Ohtsubo Eiichi
Published: October 2006

The transforming protein of Kirsten murine sarcoma virus (Ki-MuSV) is a virally encoded 21-kilodalton protein called p21
kis
. The sequences encoding p21
kis
were genetically localized to a 1.3-kilobase segment near the 5′ end of the viral genome by assaying the capacity of a series of defined deletion mutants of molecularly cloned Ki-MuSV DNA to induce focal transformation of mouse cells. Nucleotide sequencing of a portion of this region has led to the identification of an open reading frame of 567 nucleotides coding for p21
kis
protein.
Numbers of Receptor Sites from Scatchard Graphs: Facts and Fantasies
Authors: Klotz Irving M.
Published: October 2006

Data for ligand and receptor binding presented in the format of a Scatchard graph are compared with the same data shown as bound ligand plotted against the logarithm of free ligand. From this comparison it is apparent that extrapolations in the Scatchard graph to yield total number of receptor sites are generally not correct.
Single-Channel Fluctuations in Bimolecular Lipid Membranes Induced by Rat Olfactory Epithelial Homogenates
Authors: Vodyanoy Vitaly , Murphy Randall B.
Published: October 2006

Chemosensitive single-channel fluctuations were observed to be induced in essentially solvent-free lipid bimolecular membranes by the addition of sonicated homogenates of rat olfactory epithelium. The chemosensitive channels were not observed when respiratory epithelium homogenates were used instead. Ionic selectivity is consistent with potassium ions as the charge carrier. These channels may be associated with the initial events of chemoreception in the rat olfactory epithelium.
Behavioral Sensitivity to Purinergic Drugs Parallels Ethanol Sensitivity in Selectively Bred Mice
Authors: Proctor William R. , Dunwiddie Thomas V.
Published: October 2006

Behavioral responses to an adenosine receptor agonist and antagonist were examined in mice genetically selected for differential sensitivity to the soporific effects of ethanol. Both ethanol and the adenosine receptor agonist L-phenylisopropyladenosine had greater sedative and hypothermic effects in ethanol-sensitive "long-sleep" mice than in ethanol-insensitive "short-sleep" mice. Long-sleep mice were also more sensitive to the excitatory behavioral effects of theophylline, an adenosine receptor antagonist. These data suggest that adenosine may be an endogenous mediator of responses to ethanol.
Inhibition of Aldosterone Production by an Atrial Extract
Authors: Atarashi Keiichiro , Mulrow Patrick J. , Franco-Saenz Roberto , Snajdar Rudolf , Rapp John
Published: October 2006

Crude extracts of rat atria reduced the basal amount of aldosterone released from rat zona glomerulosa cells and partially inhibited aldosterone stimulation by adrenocorticotropic hormone and angiotensin II. The destruction of this activity by trypsin suggests that the active factor is a peptide, possibly atrial natriuretic factor. These data suggest that atrial natriuretic factor affects sodium excretion by the kidneys both directly and through the inhibition of aldosterone production.
Impact of Genetic Manipulation on Society and Medicine
Authors: Motulsky Arno G.
Published: October 2006

Human beings have been manipulating the genetic characteristics of plants and animals since the introduction of agriculture. Indirect manipulation of human genes occurred with widespread use of public health and medical measures that preserve genes causing disease. The production of biologicals by DNA technology raises few ethical problems. Predictive medicine in which genetic markers (including DNA variants) are used for antenatal and preclinical diagnosis of genetic diseases and susceptibilities poses new questions of confidentiality, private versus societal goals, and self-determination. When normal DNA is used to treat the somatic cells of patients with hemoglobinopathies and other genetic diseases, no new ethical problems arise beyond those presented by any novel theory. In contrast, manipulation of DNA in human fertilized eggs would constitute a qualitative departure from previous therapies since this would affect future generations. In order to be able to make wise decisions on these matters the public must be well informed. Thus, formal and informal education in human biology and genetics must be improved at all levels.
Inverse Relation Between Low-Density Lipoprotein-Cholesterol and Dehydroisoandrosterone Sulfate in Human Fetal Plasma
Authors: Parker C. Richard , Simpson Evan R. , Bilheimer David W. , Leveno Kenneth , Carr Bruce R. , MacDonald Paul C.
Published: October 2006

A striking inverse correlation was found in umbilical cord plasma between the concentrations of dehydroisoandrosterone sulfate and low-density lipoprotein (LDL)-cholesterol but not high-density lipoprotein-cholesterol or very low density lipoprotein-cholesterol. Dehydroisoandrosterone sulfate is a major secretory product of the human fetal adrenal and the principal precursor of placental estrogen production. The data suggest that the concentrations for LDL-cholesterol in fetal plasma are influenced by the rate of utilization of LDL-cholesterol by the fetal adrenal for steroidogenesis and are not necessarily related to a genetic predisposition for hypercholesterolemia or other lipoprotein disorders.
Methylation Increases Sodium Transport into A6 Apical Membrane Vesicles: Possible Mode of Aldosterone Action
Authors: Sariban-Sohraby Sarah , Burg Maurice , Wiesmann William P. , Chiang Peter K. , Johnson John P.
Published: October 2006

When isolated apical membrane vesicles prepared from cultured A6 epithelia were incubated in vitro with the methyl donor
S
-adenosylmethionine, the control rate of amiloride-inhibitable sodium transport was doubled. The methylation inhibitors 3-deazaadenosine and
S
-adenosyl homocysteine returned the
S
-adenosylmethionine-stimulated sodium transport to control levels. Neither these agents nor adenosine affected sodium transport into control vesicles. In vesicles incubated with
S
-adenosyl-[
3
H-methyl]methionine, both membrane phospholipids and proteins were labeled, and this labeling was inhibited by deazaadenosine. In vesicles prepared from A6 cells treated with aldosterone, sodium transport was twice the control value and
S
-adenosylmethionine did not cause any further stimulation of transport. In those vesicles, both lipid and protein methylation were increased. These results suggest that methylation, which increases the rate of amiloride-sensitive sodium transport, is involved in the action of aldosterone at the apical membrane level in epithelia.
Selective Deficits in the Sense of Smell Caused by Chemical Modification of the Olfactory Epithelium
Authors: Mason J. Russell , Clark L. , Morton Thomas Hellman
Published: October 2006

A chemically selective procedure for covalent modification of Schiff base-forming binding sites in proteins is demonstrated in vitro. In vivo studies show that the same procedure produces a selective anosmia ("odor blindness") when applied to the olfactory epithelia of experimental animals. Surgical experiments confirm that the sense of smell is specifically affected.
Clot-Selective Coronary Thrombolysis with Tissue-Type Plasminogen Activator
Authors: Bergmann Steven R. , Fox Keith A. A. , Ter-Pogossian Michel M. , Sobel Burton E. , Collen Désiré
Published: October 2006

Coronary thrombolysis, an intervention that can abort the sequelae of acute myocardial infarction, was accomplished within 10 minutes in dogs by intravenous administration of clot-selective, tissue-type plasminogen activator. In addition to inducing clot lysis, this promising fibrinolytic agent restored intermediary metabolism and nutritional myocardial blood flow, detectable noninvasively with positron tomography, without inducing a systemic fibrinolytic state.
Human Lateralization from Head to Foot: Sex-Related Factors
Authors: Levy Jerre , Levy Jerome M.
Published: October 2006

Sex differences in the pattern and maturation of lateral asymmetries of the human brain have been recently found by a number of investigators, suggesting that sex-related factors may differentially affect the two sides of the body. In this study, asymmetries in the size of the two feet were strongly related to sex and handedness, right-handed males having larger right feet and right-handed females having larger left feet, the reverse being seen in non-right-handed individuals. Since these differences were apparent even in children younger than 6 years, the fetal sex steroids may be critical in governing the maturation of both cerebral and pedal asymmetries.
The Jet Stream Microbeveler: An Inexpensive Way to Bevel Ultrafine Glass Micropipettes
Authors: Ogden Thomas E. , Citron Mark C. , Pierantoni Ruggero
Published: October 2006

Ultrafine glass micropipettes can be easily beveled in a jet stream of grinding compound suspended in saline. The beveling is gradual and continuous, highly reliable, and can be accomplished with common laboratory apparatus. The beveled electrodes are comparable in performance to those prepared with expensive commercial bevelers.
Ultraviolet Visual Pigment in a Vertebrate: A Tetrachromatic Cone System in the Dace
Authors: Harosi Ferenc I. , Hashimoto Yoko
Published: October 2006

Microspectrophotometric measurements of optically isolated photoreceptors in the Japanese dace, a cyprinid fish, revealed four spectroscopically distinguishable cone pigments and one rod pigment. A visual pigment that absorbs in the near ultraviolet was found in small single cones.
Heterogeneity of Normal Human Diploid Fibroblasts: Isolation and Characterization of One Phenotype
Authors: Bordin Sandra , Page R. C. , Narayanan A. S.
Published: October 2006

Cultures of human diploid fibroblasts contain cells that respond to exposure to the first component of complement (C1) by initiating DNA synthesis and growth. The plasma membranes of these cells have specific binding sites for the C1q subcomponent of C1. A fluorescence-activated cell sorter was used to isolate a subset of cells with a high affinity for C1q, and the growth and synthesis activities of these high-affinity cells were studied after numerous replications in vitro. These cells synthesize DNA and grow faster than the parent cultures and low-affinity cells, and they produce two to three times as much protein. About 40 percent of their total protein synthesis activity is directed to collagen production, unusually high proportions of collagen types III and V being produced. These properties and the high affinity of the cells for C1q are retained for at least six cell transfers. This phenotype has the properties expected of fibroblasts in healing wounds and inflamed tissues.
Fragile Sites in Chromosomes: Possible Model for the Study of Spontaneous Chromosome Breakage
Authors: Jacky Peter B. , Beek Bernd , Sutherland Grant R.
Published: October 2006

The tissue culture condition that is required for the type of chromosome breakage seen at most fragile sites, namely, the absence of folic acid and thymidine in the medium, greatly enhanced micronucleus formation in proliferating lymphocyte cultures from normal individuals. This suggests that chromosome breakage at fragile sites and the apparently spontaneous damage that gives rise to micronuclei are controlled by the same mechanism.
Visual Sustained Attention: Image Degradation Produces Rapid Sensitivity Decrement Over Time
Authors: Nuechterlein Keith H. , Parasuraman Raja , Jiang Qiyuan
Published: October 2006

Perceptual sensitivity to a visual target presented in a random continuous sequence of targets and nontargets decreased rapidly over time when stimuli were highly degraded visually but not when moderately degraded or undegraded. Large declines in sensitivity, independent of changes in response criterion, were found after only 5 minutes of observation. These rapid decrements of sensitivity to degraded targets seem to result from demands on the limited capacity of visual attention.
Evidence for Sensory-Selective Set in Young Infants
Authors: Anthony Bruno J. , Graham Frances K.
Published: October 2006

The existence of low-level filtering of sensory input is a point of debate among cognitive theorists. This present study suggests that filtering by modality exists at levels low enough to modulate the brainstem blink reflex and that it is evident as early as the 16th week of life. During foreground listening or looking conditions, blinks elicited by acoustic or visual probes were larger when probe and foreground modality matched than when they mismatched. "Interesting" foregrounds, by comparison with "dull" ones, intensified the modality-selective effect.
Virulent
Naegleria fowleri
in an Indoor Swimming Pool
Authors: Kadlec Vít , Červa Lubor , Škvárová Jiřina
Published: October 2006

A reservoir of pathogenic
Naegleria fowleri
has been located in the cracked wall of a swimming pool where repeated outbreaks of primary amoebic meningoencephalitis were observed between 1962 and 1965.
Heart Imaging with Cationic Complexes of Technetium
Authors: Deutsch Edward , Bushong William , Glavan Kenneth A. , Elder R. C. , Sodd Vincent J. , Scholz Kenneth L. , Fortman Donald L. , Lukes Steven J.
Published: October 2006

The cationic technetium-99 complex trans-[
99
TC(dmpe)
2
Cl
2
]
+
, where dmpe is bis(1,2-dimethylphosphino)ethane or (CH
3
)
2
P-CH
2
CH
2
-P(CH
3
)
2
, has been prepared and characterized by single-crystal, x-ray structural analysis. The technetium-99
m
analog, trans-(

99
m

Tc(dmpe)
2
Cl
2
]
+
, has also been prepared and shown to yield excellent gamma-ray images of the heart. The purposeful design, characterization, and synthesis of this technetium-99
m
radiopharmaceutical represents a striking application of fundamental inorganic chemistry to a problem in applied nuclear medicine.
Kepone-Induced Scoliosis and Its Histological Consequences in Fish
Authors: Couch John A. , Winstead James T. , Goodman Larry R.
Published: October 2006

Scoliosis in fish is caused by several diverse agents that possibly act on the central nervous system, neuromuscular junctions, or ionic metabolism. The organochlorine pesticide Kepone induces scoliosis in the sheepshead minnow. Some effects associated with Kepone-induced scoliosis in these fish are disruption of myotomal patterns, inter- and intramuscular hemorrhage, fractured centra of vertebrae, and death. The histological syndrome of Kepone poisoning in fish and the clinical syndrome in humans suggest that the nervous system is a primary target for Kepone and that scoliosis is a secondary effect of Kepone poisoning in fish.
War Gases as Olfactory Probes
Authors: Criswell Darrell W. , McClure F. L. , Schaefer Rollie , Brower K. R.
Published: October 2006

The tear gas ethyl bromoacetate is a fruity-smelling alkylating agent that blocks the ability of the frog nose to respond to esters and a variety of other odorants, but leaves sensitivity to amines unimpaired. Lachrymators and chemical warfare agents of other functional types such as sulfides (mustard gas) and amines (nitrogen mustards) may have similarly specific actions that will enable their use as chemical probes of the sense of smell.
Actin Distribution Patterns in the Mouse Neural Tube During Neurulation
Authors: Sadler T. W. , Greenberg D. , Coughlin P. , Lessard J. L.
Published: October 2006

With the use of antibodies to actin and indirect immunofluorescent techniques regions of increased actin concentration were demonstrated first in basal and later in apical areas of mouse neuroepithelial cells. These patterns of staining corresponded to shape changes observed in cranial neural folds as they initially elevated from the neural plate and later moved toward the midline.
Cardiovascular Research: Decades of Progress, a Decade of Promise
Authors: Levy Robert I. , Moskowitz Jay
Published: October 2006

Mortality due to cardiovascular diseases has decreased more than 30 percent in the last 30 years, and this decline has accelerated so much that over 60 percent of it has occurred between 1970 and 1980. The past and present contributions of advances in cardiovascular research to this decline are reviewed. Although there have been significant research accomplishments, too many people still die of heart and blood vessel diseases. Continued emphasis must be placed on research in the areas of etiology and pathogenesis, on validating potentially beneficial research hypotheses, and on the translation and dissemination of research results to the health care practitioner and the public. Only then can our long-term goal, the prevention of cardiovascular disease, be fully realized.
Associative Learning in Premature Hydranencephalic and Normal Twins
Authors: Tuber David S. , Berntson Gary G. , Bachman David S. , Allen J. Norman
Published: October 2006

A hydranencephalic infant lacking cerebral hemispheres and a normal twin were tested for associative learning. After repeated trials in which two stimuli were temporally paired, test trials were given in which the second stimulus was omitted. Cardiac orienting responses to stimulus omission indicated that learning had taken place in both infants.
Vasopressin Analogs That Antagonize Antidiuretic Responses by Rats to the Antidiuretic Hormone
Authors: Sawyer W. H. , Pang P. K. T. , Seto J. , McEnroe M. , Lammek B. , Manning M.
Published: October 2006

Four new synthetic analogs of vasopressin (antidiuretic hormone) can antagonize the antidiuretic response to intravenous vasopressin in anesthetized, water-loaded rats. They also cause a diuresis resembling that of diabetes insipidus when given intraperitoneally to conscious rats. Such antagonists may prove to be useful both pharmacologically and therapeutically.
Temporal Coding of Species Recognition Signals in An Electric Fish
Authors: Hopkins Carl D. , Bass Andrew H.
Published: October 2006

An electric fish in the African family Mormyridae recognizes members of its own species by "listening" to electric organ discharges, which are species-specific signatures. Reactions of fish in the field and of individual electroreceptors to both normal and modified computer-synthesized discharges emphasize the importance of the waveform (time-domain cues) in species recognition.
Motility Assay of Human Sperm by Photon Correlation Spectroscopy
Authors: Frost James , Cummins H. Z.
Published: October 2006

Microscopic methods of performing motility assays of spermatozoa are slow, subjective, and involve a small number of spermatozoa. Laser light-scattering methods can analyze the motility of many spermatozoa within minutes. The swimming speed distribution of human spermatozoa was investigated by photon correlation spectroscopy. The sperm was diluted in seminal plasma to avoid modifying the viscosity. The swimming speed distribution was reconstructed from the correlation data by Stock's method of splines. When compared with a videomicroscopic assay, the reconstructed swimming speed distribution accurately reflects translational motion between 0 and 80 micrometers per second, while for speeds greater than 80 micrometers per second the distribution is distorted by the effects of rotational motion.
Regenerating Axons Reclaim Sensory Targets from Collateral Nerve Sprouts
Authors: Jackson Patrick C. , Diamond Jack
Published: October 2006

There is a critical period for the sprouting of intact low-threshold mechanosensory cutaneous nerves in rats; functional invasion of adjacent denervated skin does not occur in animals older than about 20 days of age, and it is largely confined to denervated skin within the "domain" of the parent dermatome. These nerves can regenerate readily in the adult, however, and such regenerating nerves do not respect domain borders; moreover, they functionally displace endings of intact nerves that earlier had sprouted into denervated skin.
Cytosolic and Microsomal Epoxide Hydrolases: Differential Properties in Mammalian Liver
Authors: Ota Kenji , Hammock Bruce D.
Published: October 2006

The epoxide hydrolase activities of the 100,000g pellet (microsomal) and 100,000g soluble (cytosolic) fractions of mouse, rat, and guinea pig liver were measured with three closely related compounds used as substrates. Differences between the species in the distribution of the cytosolic and microsomal hydrolases and in their substrate specificities and
p
H optima demonstrate why epoxide hydrolase activity in the cytosolic fraction was not detected earlier in spite of intensive work on the microsomal epoxide hydrolase.
Kindling Induces Long-Lasting Alterations in Response of Hippocampal Neurons to Elevated Potassium Levels in Vitro
Authors: Oliver Adolphus P. , Hoffer Barry J. , Wyatt Richard Jed
Published: October 2006

The cellular basis of kindling was studied electrophysiologically with slices of guinea pig hippocampus. Normally, epileptiform activity can be induced in the slices only by combined exposure to elevated potassium levels and a chemical convulsant such as penicillin. In hippocampal slices from pentylenetetrazole-kindled animals, however, elevated potassium alone can induce seizures. These data suggest that kindling elicits long-term changes in neuronal excitability that may involve ionic mechanisms.
The Spinal Frog Takes into Account the Scheme of Its Body During the Wiping Reflex
Authors: Fukson Olga I. , Berkinblit Michael B. , Feldman Anatoly G.
Published: October 2006

The hindlimb of the spinal frog produces a wiping reflex evoked by electrically or chemically stimulating distal skin of the forelimb. The reflex was released in frogs supported on a flat surface or suspended. It was found to have two stages. During the first, the frog fixed the hindlimb in an intermediate posture irrespective of forelimb position. In the second, the movement depended on forelimb position, which determined the final posture of the hindlimb. In this final posture, all joints except the hip joint were fully extended; the hip angle was correlated with forelimb position and varied on repeated wipings. When the stimulus was applied to the skin of the back, the pattern of final postures was the same, but the intermediate postures differed. The organization of the wiping reflex is discussed in light of the hypothesis that movement is evoked according to changes in the equilibrium (postural state) of the system.
Abolition of Optokinetic Nystagmus in the Cat
Authors: Harris Laurence R. , Lepore Franco , Guillemot Jean-Paul , Cynader Max
Published: October 2006

Combining a behavioral and a surgical manipulation, namely complete visual deprivation with surgical section of the optic chiasm, results in the abolition of optokinetic nystagmus in the cat. This basic optomotor reflex remains relatively unaffected by either of these manipulations performed singly.
Aspergillus flavus
and Aflatoxin in Iowa Corn Before Harvest
Authors: Lillehoj E. B. , Fennell D. I. , Kwolek W. F.
Published: October 2006

Aspergillus flavus
and aflatoxin were detected in ears of Iowa corn on plants before harvest in 1975. Presence of the fungus was associated with kernel injury caused by the second generation European corn borer. Amounts of aflatoxin B
1
in corn from a limited number of selected ears ranged from 1 part per billion to 1560 parts per billion with a mean of 430 parts per billion.
Attempts to Mimic Docking Processes of the Immune System: Recognition-Induced Formation of Protein Multilayers
Authors: Müller W. , Ringsdorf H. , Rump E. , Wildburg G. , Zhang X. , Angermaier L. , Knoll W. , Liley M. , Spinke J.
Published: October 2006

The assemblage of protein multilayers induced by molecular recognition, as seen, for example, in the immune cascade, has been mimicked by using streptavidin as a docking matrix. For these experiments, this protein matrix was organized on liposomes, monolayers at the air-water interface, and self-assembled layers on gold, all three containing biotin lipids. The docking of streptavidin to biotin at liposomal surfaces was confirmed by circular dichroism. Mixed double and triple layers of streptavidin, concanavalin A, antibody Fab fragments, and hormones were prepared at the air-water interface and on gold surfaces and were characterized by fluorescence microscopy and plasmon spectroscopy. With the use of biotin analogs that have lower binding constants it has been possible to achieve multiple formation and competitive replacement of the oriented protein assemblages.
Pyrrolizidine Alkaloids: Their Occurrence in Honey from Tansy Ragwort (
Senecio jacobaea
L.)
Authors: Deinzer M. L. , Thomson P. A. , Burgett D. M. , Isaacson D. L.
Published: October 2006

The hepatotoxic alkaloids known to occur in tansy ragwort (
Senecio jacobaea
L.) are also present in honey produced from the nectar of this species. These alkaloids, which inclued senecionine, seneciphylline, jacoline, jaconine, jacobine, and jacozine, are potentially carcinogenic, mutagenic, and teratogenic and may pose health hazards to the human consumer.
Concomitant Elevations in Serum Sialyltransferase Activity and Sialic Acid Content in Rats with Metastasizing Mammary Tumors
Authors: Bernacki Ralph J. , Kim Untae
Published: October 2006

Rats with transplantable spontaneously metastasizing mammary tumors have elevated levels of both serum sialoglycoconjugate and serum sialyltransferase activity compared with normal female rats or rats with various nonmetastasizing mammary tumors. A direct relationship was observed between the amount of serum protein-bound sialic acid and serum sialyltransferase activity in all rats studied. Serum sialyltransferase activity in rats with a representative metastasizing mammary tumor, SMT-2A, was also correlated with tumor age. Microsomes prepared from the SMT-2A tumor have a sixfold higher sialyltransferase activity than do microsomes prepared from the nonmetastasizing mammary tumor MT-W9B. Normal rat liver microsomes have the same level of activity as microsomes prepared from livers of animals with either SMT-2A or MT-W9B tumors. The data indicate that spontaneously metastasizing mammary tumor cells have an increased production and release, perhaps through cell surface shedding, of a sialyltransferase. It is suggested that this sialyltransferase may increase the serum half-life of certain tumor-specific circulating glycoconjugates by increasing the content of protein-bound sialic acid and may thereby play a role in the immune escape mechanism of metastasizing tumor cells.
DNA Conformation-Induced Activation of an Enediyne for Site-Specific Cleavage
Authors: Kappen Lizzy S. , Goldberg Irving H.
Published: October 2006

Neocarzinostatin chromophore (NCS chrom) was found to induce site-specific cleavage at the 3′ side of a bulge in single-stranded DNA in the absence of thiol. This reaction involved the oxidative formation of a DNA fragment with a nucleoside 5′-aldehyde at its 5′ terminus and generated an ultraviolet light-absorbing and fluorescent species of post-activated drug containing tritium abstracted from the carbon at the 5′ position of the target nucleotide. The DNAs containing point mutations that disrupt the bulge were not cleavage substrates and did not generate this drug product. Thus, DNA is an active participant in its own destruction, and NCS chrom may be useful as a probe for bulged structures in nucleic acids.
IRS-1: Essential for Insulin- and IL-4-Stimulated Mitogenesis in Hematopoietic Cells
Authors: Wang Ling-Mei , Myers Martin G. , Sun Xiao-Jian , Aaronson Stuart A. , White Morris , Pierce Jacalyn H.
Published: October 2006

Although several interleukin-3 (IL-3)-dependent cell lines proliferate in response to IL-4 or insulin, the 32D line does not. Insulin and IL-4 sensitivity was restored to 32D cells by expression of IRS-1, the principal substrate of the insulin receptor. Although 32D cells possessed receptors for both factors, they lacked the IRS-1–related protein, 4PS, which becomes phosphorylated by tyrosine in insulin- or IL-4–responsive lines after stimulation. These results indicate that factors that bind unrelated receptors can use similar mitogenic signaling pathways in hematopoietic cells and that 4PS and IRS-1 are functionally similar proteins that are essential for insulin- and IL-4–induced proliferation.
Environmental Degradation of 2,3,7,8-Tetrachlorodibenzo-
p
-dioxin (TCDD)
Authors: Crosby Donald G. , Wong Anthony S.
Published: October 2006

Herbicide formulations containing known amounts of 2,3,7,8-tetrachlorodibenzo-
p
-dioxin (TCDD) and exposed to natural sunlight on leaves, soil, or glass plates lost most or all of the TCDD during a single day, due principally to photochemical dechlorination. Despite the known persistence of pure TCDD, it is not stable as a contaminant in thin herbicide films exposed to outdoor light.
Similarity of the Yeast RAD51 Filament to the Bacterial RecA Filament
Authors: Ogawa Tomoko , Yu Xiong , Shinohara Akira , Egelman Edward H.
Published: October 2006

The RAD51 protein functions in the processes of DNA repair and in mitotic and meiotic genetic recombination in the yeast
Saccharomyces cerevisiae
. The protein has adenosine triphosphate-dependent DNA binding activities similar to those of the Escherichia coli RecA protein, and the two proteins have 30 percent sequence homology. RAD51 polymerized on double-stranded DNA to form a helical filament nearly identical in low-resolution, three-dimensional structure to that formed by RecA. Like RecA, RAD51 also appears to force DNA into a conformation of approximately a 5.1-angstrom rise per base pair and 18.6 base pairs per turn. As in other protein families, its structural conservation appears to be stronger than its sequence conservation. Both the structure of the protein polymer formed by RecA and the DNA conformation induced by RecA appear to be general properties of a class of recombination proteins found in prokaryotes as well as eukaryotes.
Scientific and Social Issues of Human Immunodeficiency Virus Vaccine Development
Authors: Haynes Barton F.
Published: October 2006

Development of a preventive immunogen for human immunodeficiency virus (HIV) infection is a national priority. The complexities associated with HIV host-virus interactions, coupled with the rapid progression of the HIV epidemic worldwide, have necessitated lowering expectations for an HIV vaccine that is 100 percent effective and have raised important scientific and nonscientific issues regarding development and use of preventive and therapeutic HIV vaccines.
Switch of CD8 T Cells to Noncytolytic CD8
-
CD4
-
Cells that Make T
H
2 Cytokines and Help B Cells
Authors: Erard François , Wild Marie-Thérèse , Garcia-Sanz Jose A. , Le Gros Graham
Published: October 2006

CD8
+
T cells are a major defense against viral infections and intracellular parasites. Their production of interferon-γ (IFN-γ) and their cytolytic activity are key elements in the immune response to these pathogens. Mature mouse CD8
+
T cells that were activated in the presence of interleukin-4 (IL-4) developed into a CD8
-
CD4
-
population that was not cytolytic and did not produce IFN-γ. However, these CD8
-
cells produced large amounts of IL-4, IL-5, and IL-10 and helped activate resting B cells. Thus, CD8 effector functions are potentially diverse and could be exploited by infectious agents that switch off host protective cytolytic responses.
Competition of Δ
9
-Tetrahydrocannabinol with Estrogen in Rat Uterine Estrogen Receptor Binding
Authors: Rawitch Allen B. , Schultz Gregory S. , Ebner Kurt E. , Vardaris Richard M.
Published: October 2006

Direct competition experiments with Δ
9
-tetrahydrocannibinol (Δ
9
-THC) and estradiol in binding assays with rat uterine cytosol estrogen receptors showed that Δ
9
-THC was a weak, but nevertheless significant, competitor for binding to cytoplasmic estrogen receptors. These data support, at the molecular level, the observations that Δ
9
-THC has a weak estrogenic activity (at least the ability to bind to estrogen receptors). Moreover, estrogen-like binding suggests that Δ
9
-THC, acting at the level of estrogen receptor, causes a primary estrogenic effect rather than an indirect or secondary phenomenon.
Virus Transfer from Surf to Wind
Authors: Baylor E. R. , Baylor M. B. , Blanchard Duncan C. , Syzdek Lawrence D. , Appel Curtis
Published: October 2006

Bubbles in the sea surf adsorb and carry viruses to the surface where they are propelled into the air on tiny jets of seawater when the bubble bursts. The ejected jets become tiny drops of aerosol. The bubble adsorption and virus concentration in the surf is analogous to industrial bubble levitation processes that concentrate metallic ores, enzymes, and finely divided organic crystals. Bubble levitation of viruses deliberately injected into the surf produced 200 times more virus per milliliter in the aerosol than were present in samples from the surf. Some aerosol drops created by the surf and carried by the wind fall out on the beach. The frequency of virus-bearing drops, that is, the number of plaques on seeded plates exposed on the beach, decreased exponentially with the distance downwind from the surf.
Bat Mortality: Pesticide Poisoning and Migratory Stress
Authors: Geluso Kenneth N. , Altenbach J. Scott , Wilson Don E.
Published: October 2006

Organochlorine residues in the fat of young Mexican free-tailed bats,
Tadarida brasiliensis
, reached the brain and caused symptoms of poisoning after the fat mobilization that takes place during migratory flight was simulated. These chemical body burdens were obtained naturally under free-living conditions at the maternity roost. The data obtained support the hypothesis that pesticides have contributed to recent declines in populations of this bat.
A WEIGHTED NETWORK MODEL FOR RAILWAY TRAFFIC
Authors: LI KEPING , GAO ZIYOU , MAO BAOHUA
Published: October 2006

In this paper, we present a weighted network model for the simulation of railway network. Here the stations and section tracks of the railway network are respectively regarded as the nodes and edges of the network model. Using the model proposed in this paper, we measure the distribution of trains and the mean waiting time of trains etc. The simulation results indicate that the proposed model can be successfully used for the simulation of railway network. Some phenomena observed in real railway networks can be reproduced, such as the characteristic behavior of train movement. A comparison with real data for the Netherlands (i.e., the Dutch railway network) is included. It supports the practical values of the proposed model.
Infection of human cytomegalovirus in cultured human gingival tissue
Authors: Hai Rong , Chu Alice , Li Hongjian , Umamoto Sean , Rider Paul , Liu Fenyong
Published: October 2006

Background

Human cytomegalovirus (HCMV) infection in the oral cavity plays an important role in its horizontal transmission and in causing viral-associated oral diseases such as gingivitis. However, little is currently known about HCMV pathogenesis in oral mucosa, partially because HCMV infection is primarily limited to human cells and few cultured tissue or animal models are available for studying HCMV infection.

Results

In this report, we studied the infection of HCMV in a cultured gingival tissue model (EpiGingival, MatTek Co.) and investigated whether the cultured tissue can be used to study HCMV infection in the oral mucosa. HCMV replicated in tissues that were infected through the apical surface, achieving a titer of at least 300-fold at 10 days postinfection. Moreover, the virus spread from the apical surface to the basal region and reduced the thickness of the stratum coreum at the apical region. Viral proteins IE1, UL44, and UL99 were expressed in infected tissues, a characteristic of HCMV lytic replication in vivo. Studies of a collection of eight viral mutants provide the first direct evidence that a mutant with a deletion of open reading frame US18 is deficient in growth in the tissues, suggesting that HCMV encodes specific determinants for its infection in oral mucosa. Treatment by ganciclovir abolished viral growth in the infected tissues.

Conclusion

These results suggest that the cultured gingival mucosa can be used as a tissue model for studying HCMV infection and for screening antivirals to block viral replication and transmission in the oral cavity.
The variable colours of the fiddler crabUca vomerisand their relation to background and predation
Authors: Hemmi Jan M. , Marshall Justin , Pix Waltraud , Vorobyev Misha , Zeil Jochen
Published: October 2006

Colour changes in fiddler crabs have long been noted, but a functional interpretation is still lacking. Here we report that neighbouring populations of Uca vomeris in Australia exhibit different degrees of carapace colours, which range from dull mottled to brilliant blue and white. We determined the spectral characteristics of the mud substratum and of the carapace colours of U. vomeris and found that the mottled colours of crabs are cryptic against this background, while display colours provide strong colour contrast for both birds and crabs, but luminance contrast only for a crab visual system. We tested whether crab populations may become cryptic under the influence of bird predation by counting birds overflying or feeding on differently coloured colonies. Colonies with cryptically coloured crabs indeed experience a much higher level of bird presence, compared to colourful colonies. We show in addition that colourful crab individuals subjected to dummy bird predation do change their body colouration over a matter of days. The crabs thus appear to modify their social signalling system depending on their assessment of predation risk.
Locomotor kinetics and kinematics on inclines and declines in the gray short-tailed opossumMonodelphis domestica
Authors: Lammers Andrew R. , Earls Kathleen D. , Biknevicius Audrone R.
Published: October 2006

Small terrestrial animals continually encounter sloped substrates when moving about their habitat; therefore, it is important to understand the mechanics and kinematics of locomotion on non-horizontal substrates as well as on level terrain. To this end, we trained gray short-tailed opossums(Monodelphis domestica) to move along level, 30° inclined, and 30° declined trackways instrumented with a force platform. Vertical,craniocaudal and mediolateral impulses, peak vertical forces, and required coefficient of friction (μreq) of individual limbs were calculated. Two high speed video cameras were used to simultaneously capture whole limb craniocaudal and mediolateral angles at limb touchdown, midstance and lift-off. Patterns on the level terrain were typical for non-primate quadrupeds: the forelimbs supported the majority of the body weight, forelimbs were net braking and hindlimbs net propulsive, and both limb pairs exerted small laterally directed impulses. M. domestica moved more slowly on sloped substrates in comparison to level locomotion, and exhibited a greaterμ req. On inclines, both limb pairs were more protracted at touchdown and more retracted at lift-off, fore- and hindlimbs had equal roles in body weight support, forelimbs exerted greater propulsive impulse than hindlimbs, and μreq was greater in the forelimbs than in hindlimbs. On declines, only the forelimbs were more protracted at touchdown;forelimbs supported the great majority of body weight while they generated nearly all of the braking impulse and, despite the disparity in fore-vs hindlimb function on the decline, μreq was not significantly different between limbs. These differences on the inclined and declined surfaces most likely result from (1) the location of the opossums'center of mass, which is closer to the forelimbs than to the hindlimbs, and(2) the greater functional range of the forelimbs versus the hindlimbs.
Novel Inorganic–Organic Layered Composite Synthesized by Polycondensation of 3-Aminopropyltriethoxysilane Associated with the Self-assembly of Alkanoate
Authors: Chujo Takayuki , Gonda Yu , Oumi Yasunori , Sano Tsuneji , Yoshitake Hideaki
Published: October 2006

We synthesized a layered organosilica with a self-assembled alkanoate interlayer. The bond between the alkanoate and aminopropylsiloxane is critical for the formation of such a structure. The surfactant can be exchanged with alkanoate with a different chain length to form other lamellar structures with a corresponding basal spacing.
Molecular Modification of 2,6-Diphenylbenzo[1,2-b:4,5-b′]dichalcogenophenes by Introduction of Strong Electron-withdrawing Groups: Conversion from p- to n-Channel OFET Materials
Authors: Takimiya Kazuo , Kunugi Yoshihito , Ebata Hideaki , Otsubo Tetsuo
Published: October 2006

2,6-Diphenylbenzo[1,2-b:4,5-b′]dithiophene (DPh-BDT) and -diselenophene (DPh-BDS) as p-channel semiconducting materials were modified by introducing fluoro, cyano, or trifluoromethyl groups into the attached phenyl moieties. On examination of organic field-effect transistors fabricated using these modified compounds, the trifluoromethyl-substituted DPh-BDT and BDS derivatives were found to act as n-channel semiconductors with high electron mobilities of 0.044 and 0.10 cm2 V−1 s−1, respectively.
Telling the Stories of Heim and Heimat, Home and Exile: Recent Palestinian Films and the Iconic Parable of the Invisible Palestine
Authors: Bresheeth Haim
Published: October 2006

This article deals with the appearance of an independent stream of Palestinian documentary cinema, during the 1990's, and its specific characteristics. This it does through concentrating on three films: A Chronicle of Disappearance (Suleiman, 1996) Ustura (Hassan, 1998)
and 1948 (Bakri, 1998). The argument is supported by a number of theoretical anchorages examination of early cinema as a Lacanian mirror of self and other, the use of Ethnotopia, a concept used by Nichols and Russell, and the Freudian use of mourning and melancholia in order to deal
with personal, social and national loss, as well as an examination of narrative methods and narrativity in the three films. In all three films one element appears to rise and focus our interest story, storytelling, and narration the narrative processes appear crucial to films which work within
the documentary tradition, but also hover over the boundary with narrative cinema. This central characteristic, separating them distinctly from the mainstream of documentary film in Israel, also connects them with other strains of documentary, and specifically with Third World cinema and Arab
cinema. On this basis, the article locates the role of storytelling as a structure of identity, evidence and memory, after a long period during which this memory was repressed by the Israeli occupation and its atrocities. It seems that this memory produced in the films is capable of displacing
and neutralizing some of the power of the processes of melancholia which typify the loss referred to, and may herald a new form of cinema, as well as a new form of discourse within the Israeli and Palestinian arenas.
Molecular Oxygen To Regenerate PdII Active Species
Authors: Muzart Jacques
Published: October 2006

Palladium(II) catalysis allows various aerobic oxidation reactions, but the mechanism of the regeneration of the active catalytic species remains, in many cases, undetermined. In recent years, considerable effort has been directed toward the comprehension of the reaction of dioxygen with hydridopalladium(II) and palladium(0) complexes. This Focus Review highlights the results of these experimental and theoretical studies that can contribute to the exploitation of the powerful nature of PdII catalysis.