bluuebunny/crossref_metadata_2025 huggingface dataset:
Silver Oxide as a Novel Catalyst for Carbon–Carbon Bond-forming Reactions in Aqueous Media
Authors: Ueno Masaharu , Tanoue Arata , Kobayashi Shu
Published: May 2010

Silver oxide was found to be an excellent catalyst for allylation reactions of allyltributyltins with aldehydes in aqueous media. Despite the very low solubility of silver oxide in the media, the reactions proceeded smoothly, and the catalyst was recovered and reused. When α-methyl-substituted allyltributyltin was used as the nucleophile, the corresponding α-adducts were obtained exclusively in high yields with good anti-selectivity. A reaction mechanism including transmetalation from tin to silver is proposed.
Resource Allocation and Organizational Form
Authors: Friebel Guido , Raith Michael
Published: May 2010

We develop a theory of firm scope and structure in which merging two firms allows the integrated firm's top management to allocate resources that are costly to trade. However, information about their use resides with division managers. We show that establishing truthful upward communication raises the cost of inducing managerial effort compared with stand-alone firms. This effect dominates a positive effect on effort driven by competition for the firm's resources. We derive predictions about optimal firm scope and structure. In particular, we show why it is optimal to separate the tasks of allocating resources and running a division. (JEL D21, D23, D82, G34)
Public Goods, Social Pressure, and the Choice Between Privacy and Publicity
Authors: Daughety Andrew F , Reinganum Jennifer F
Published: May 2010

We model privacy as an agent's choice of action being unobservable to others. An agent derives utility from his action, the aggregate of agents' actions, and other agents' perceptions of his type. If his action is unobservable, he takes his full-information optimal action and is pooled with other types, while if observable, then he distorts it to enhance others' perceptions of him. This increases the public good, but the disutility from distortion is a social cost. When the disutility of distortion is high (low) relative to the marginal utility of the public good, a policy of privacy (publicity) is optimal. (JEL D82, H41)
Public Provision of Private Goods and Nondistortionary Marginal Tax Rates
Authors: Blomquist Sören , Christiansen Vidar , Micheletto Luca
Published: May 2010

Using an optimal taxation model combined with a previously neglected scheme of public provision of private goods, we show that there is an efficiency gain if public provision of selected goods replaces market purchases and that efficiency requires marginal income tax rates to be higher than if the goods were purchased in the market. Part of the marginal tax serves the same role as a market price and conveys information about a real social cost of working more hours. It might be that economies with higher marginal tax rates have less severe distortions than economies with lower marginal tax rates. (JEL H21, H42, I38)
Child Benefit Support and Method of Payment: Evidence from a Randomized Experiment in Belgium
Authors: Huysentruyt Marieke , Lefevere Eva
Published: May 2010

We examine the effects of information and information presentation format on individuals' choice of payment method in a large randomized experiment carried out with the Belgian National Office for Family Benefits. We find that a one-time mailing providing information about method of payment for child benefit support caused a fourfold increase in parents' decision to switch from payment by check to electronic payment. Simple, low-cost supplements significantly raised people's responsiveness to the mailing. Our results suggest that complexity and information (processing) costs pose significant barriers to transitioning to electronic payment methods, and that deliberate efforts to lower these costs can contribute to large behavioral changes. (JEL D83, J13)
The Micro-Geography of Tax Avoidance: Evidence from Littered Cigarette Packs in Chicago
Authors: Merriman David
Published: May 2010

The large tax differentials between Chicago and neighboring jurisdictions provide an incentive for cigarette tax avoidance. Data from a random sample of cigarette packs littered in Chicago reveals a startling degree of tax avoidance: three-quarters did not display a Chicago tax stamp. Also, the $2.68 difference between the tax in Chicago and surrounding counties decreases the probability of a local stamp by almost 60 percent, and a one mile increase in distance to the lower-tax state border increases the probability a pack of a local stamp by about one percent. These results are consistent with the predictions of economic theory. (JEL H25, H26, H71)
Optimal Taxation and Social Insurance with Endogenous Private Insurance
Authors: Chetty Raj , Saez Emmanuel
Published: May 2010

We characterize welfare gains from government intervention when the private sector provides partial insurance. We analyze models in which adverse selection, pre-existing information, or imperfect optimization create a role for government intervention. We derive formulas that map existing empirical estimates into quantitative predictions for optimal policy. When private insurance generates moral hazard, standard formulas for optimal government insurance must be modified to account for fiscal externalities. In contrast, standard formulas are unaffected by “informal” private insurance that does not generate moral hazard. Applications to health and unemployment show that formal private market insurance can significantly reduce optimal government benefit rates. (JEL D82, G22, H21, H23, J65)
The rhodanese RhdA helps Azotobacter vinelandii in maintaining cellular redox balance
Authors: Remelli William , Cereda Angelo , Papenbrock Jutta , Forlani Fabio , Pagani Silvia
Published: May 2010

The tandem domain rhodanese-homology protein RhdA ofAzotobacter vinelandiishows an active-site loop structure that confers structural peculiarity in the environment of its catalytic cysteine residue. Thein vivoeffects of the lack of RhdA were investigated using anA. vinelandiimutant strain (MV474) in which therhdAgene was disrupted by deletion. Here, by combining analytical measurements and transcript profiles, we show that deletion of therhdAgene generates an oxidative stress condition to whichA. vinelandiiresponds by activating defensive mechanisms. In conditions of growth in the presence of the superoxide generator phenazine methosulfate, a stressor-dependent induction ofrhdAgene expression was observed, thus highlighting that RhdA is important forA. vinelandiito sustain oxidative stress. The potential of RhdA to buffer general levels of oxidants inA. vinelandiicells via redox reactions involving its cysteine thiol is discussed.
Blunting the knife: development of vaccines targeting digestive proteases of blood-feeding helminth parasites
Authors: Pearson Mark S. , Ranjit Najju , Loukas Alex
Published: May 2010

Proteases are pivotal to parasitism, mediating biological processes crucial to worm survival including larval migration through tissue, immune evasion/modulation and nutrient acquisition by the adult parasite. In haematophagous parasites, many of these proteolytic enzymes are secreted from the intestine (nematodes) or gastrodermis (trematodes) where they act to degrade host haemoglobin and serum proteins as part of the feeding process. These proteases are exposed to components of the immune system of the host when the worms ingest blood, and therefore present targets for the development of anti-helminth vaccines. The protective effects of current vaccine antigens against nematodes that infect humans (hookworm) and livestock (barber's pole worm) are based on haemoglobin-degrading intestinal proteases and act largely as a result of the neutralisation of these proteases by antibodies that are ingested with the blood-meal. In this review, we survey the current status of helminth proteases that show promise as vaccines and describe their vital contribution to a parasitic existence.
Detection of breast cancer-related antigens through cDNA phage-displayed protein microarray
Authors: Bi Qun , Tan Taochao , Xiang Xi , Lu Aiping , Zhu Shenggeng
Published: May 2010

High-throughput molecular profiling techniques are helpful in the diagnosis of multifactorial disease. In this study, a cDNA-phage-displayed protein microarray using phage particles spotted directly onto it as sensors was used to detect related antigens in breast tumor sera. cDNA sequences from 17 positive clones were determined, which included some sequences encoding known breast cancer-related antigens and proteins related to other diseases, as well as proteins with unknown functions. Our results not only provide some useful information for breast cancer research, but also suggest that the strategy used here would be efficient to search for disease-related proteins and other functional target proteins.
The XPD helicase: XPanDing archaeal XPD structures to get a grip on human DNA repair
Authors: Wolski Stefanie C. , Kuper Jochen , Kisker Caroline
Published: May 2010

Xeroderma pigmentosum complementation group D protein (XPD) is an iron-sulfur cluster containing 5′-3′ helicase and, in humans, part of the transcription factor TFIIH. TFIIH is involved in nucleotide excision repair as well as in transcription initiation. Recently, three different groups have reported the structures of archaeal XPDs. All structures revealed a four-domain organization with two RecA-like domains, an Arch domain and an iron-sulfur cluster domain. It was possible to rationalize several of the mutations in the human XPD gene that lead to one of the three severe diseases xeroderma pigmentosum, Cockayne syndrome and trichothiodystrophy. The different structures are compared and disease-related mutations are discussed.
The membrane-bound bile acid receptor TGR5 (Gpbar-1) is localized in the primary cilium of cholangiocytes
Authors: Keitel Verena , Ullmer Christoph , Häussinger Dieter
Published: May 2010

Cholangiocyte cilia are sensory organelles that extend from the apical membrane into the bile duct lumen and detect changes in bile flow and osmolarity. Whether or not cholangiocyte cilia are responsive to bile acids is unknown. TGR5 (Gpbar-1) is a membrane-bound bile acid receptor which is expressed in biliary epithelial cells and promotes chloride secretion in gallbladder epithelial cells. As shown in the present study, TGR5 is localized in the primary cilium of mouse and human cholangiocytes. Here the receptor could play an important role in coupling biliary bile acid concentration and composition to ductular bile formation.
Proteolysis of platelet receptors in humans and other species
Authors: Qiao Jian L. , Shen Yang , Gardiner Elizabeth E. , Andrews Robert K.
Published: May 2010

In the past 5 years, metalloproteinase-mediated ectodomain shedding of platelet receptors has emerged as a new mechanism for modulating platelet function. By regulating surface expression of the platelet-specific receptors, glycoprotein (GP)VI that binds collagen, and GPIbα (the major ligand-binding subunit of the GPIb-IX-V complex) that binds von Willebrand factor (VWF) and other procoagulant and proinflammatory ligands, shedding not only irreversibly downregulates GPVI/GPIbα function, but generates proteolytic fragments that might be unique biomarkers or modulators in plasma. This is potentially significant because GPVI and GPIbα are involved in initiating thrombotic diseases such as heart attack and stroke, as well as autoimmune diseases where anti-platelet antibodies result in thrombocytopenia. Altered expression levels of GPIbα/GPVI are associated with both thrombotic propensity and platelet aging, suggesting an additional role in platelet clearance. Although emerging data are elucidating molecular mechanisms underlying GPIbα/GPVI shedding, evidence for the functional consequences of sheddingin vivo, either clinically or in animal models, is far more limited. Here we consider recent published evidence for GPVI or GPIbα shedding in humans, nonhuman primates and mice, and whether conservation of sheddase cleavage sites across species points to a functional role for metalloproteolytic sheddingin vivo.
Sprouty4 levels are increased under hypoxic conditions by enhanced mRNA stability and transcription
Authors: Haigl Barbara , Mayer Christoph-Erik , Siegwart Gerald , Sutterlüty Hedwig
Published: May 2010

Sprouty (Spry) proteins are well-known negative regulators of receptor tyrosine kinase-mediated signalling. Their expression is controlled by mitogens, implying a negative feedback loop. Correspondingly, the different members of the family fulfil important roles during organogenesis by adjustment of growth factor-induced processes. In addition, Spry4, one member of this protein family, has been shown to regulate angiogenesis by inhibiting vascular endothelial cell growth factor-induced extracellular signalling-regulated kinase (ERK) activation. Because oxygen is an important regulator of angiogenesis, we investigated Spry4 expression patterns under hypoxic conditions. Our data demonstrate that both hypoxia and desferrioxamine (DFO) treatment increased Spry4 expression. Following iron depletion, elevated Spry4 levels were detected in several cell types independent of tissue origin, presence of mitogens, cell differentiation and malignancy. Evaluation of the underlying regulative mechanisms revealed that augmented transcription and increased mRNA stability enhance mRNA levels of Spry4 in response to DFO. This study unveils a growth factor-independent regulation mechanism of Spry4 expression. Because increased Spry4 levels are accompanied by disappearing ERK phosphorylation, Spry4 might be involved in the timely restriction of MAPK signals under hypoxic conditions, similar to its role in mitogen-regulated processes. However, the functional significance of the observed upregulation of Spry4 during iron depletion remains to be clarified.
Degradation of human kininogens with the release of kinin peptides by extracellular proteinases of Candida spp.
Authors: Rapala-Kozik Maria , Karkowska-Kuleta Justyna , Ryzanowska Agnieszka , Golda Anna , Barbasz Anna , Faussner Alexander , Kozik Andrzej
Published: May 2010

The secretion of proteolytic enzymes by pathogenic microorganisms is one of the most successful strategies used by pathogens to colonize and infect the host organism. The extracellular microbial proteinases can seriously deregulate the homeostatic proteolytic cascades of the host, including the kinin-forming system, repeatedly reported to be activated during bacterial infection. The current study assigns a kinin-releasing activity to secreted proteinases ofCandidaspp. yeasts, the major fungal pathogens of humans. Of severalCandidaspecies studied,C. parapsilosisandC. albicansin their invasive filamentous forms are shown to produce proteinases which most effectively degrade proteinaceous kinin precursors, the kininogens. These enzymes, classified as aspartyl proteinases, have the highest kininogen-degrading activity at low pH (approx. 3.5), but the associated production of bradykinin-related peptides from a small fraction of kininogen molecules is optimal at neutral pH (6.5). The peptides effectively interact with cellular B2-type kinin receptors. Moreover, kinin-related peptides capable of interacting with inflammation-induced B1-type receptors are also formed, but with a reversed pH dependence. The presented variability of the potential extracellular kinin production by secreted aspartyl proteinases ofCandidaspp. is consistent with the known adaptability of these opportunistic pathogens to different niches in the host organism.
Molecular contortionism – on the physical limits of serpin ‘loop-sheet’ polymers
Authors: Huntington James A. , Whisstock James C.
Published: May 2010

Members of the serpin (serineproteaseinhibitor) superfamily fold into a metastable conformation that is crucial for proper function. As a consequence, serpins are susceptible to mutations that cause misfolding and the intracellular accumulation of pathogenic polymers. The mechanism of serpin polymerisation remains to be resolved, however, over the past two decades the ‘loop-sheet’ hypothesis has gained wide acceptance. In this mechanism the reactive centre loop of one serpin monomer inserts into the β-sheet A of another (in trans), in a manner similar to what is seen for reactive centre loop-cleaved and latent conformations (in cis). The hypothesis has been refined in response to certain experimental data, but it has proved difficult to assess the various propositions without creating molecular models. Here we evaluate the loop-sheet mechanism by creating models of pentamers of the archetypal serpin α1-antitrypsin. We conclude that an inescapable consequence of the loop-sheet mechanism is polymer compaction and rigidity, properties that are inconsistent with the ‘beads-on-a-string’ morphology of polymers obtained from human tissue. The recent crystal structure of a domain-swapped serpin dimer suggests an alternative mechanism that is consistent with known polymer properties, including the requirement of partial unfolding to induce polymer formationin vitro, and polymerisation from a folding intermediatein vivo.
Proteases in lymphocyte killer function: redundancy, polymorphism and questions remaining
Authors: Sutton Vivien R. , Trapani Joseph A.
Published: May 2010

Proteases of the serine and cysteine protease families are involved in many processes crucial to the lytic functions of cytotoxic T lymphocytes and natural killer cells. In this study we describe those functions and attempt to place them in the pathophysiological context of defence to pathogen invasion. In particular, we stress that the co-evolution of pathogens with the immune systems of higher organisms over evolutionary time has ensured that redundancy, flexibility and polymorphism of the proteases can be identified, both within the protease repertoire of a given species, and by comparing orthologous protease functions across species.
Structural insights into the evolution of the adaptive immune system: the variable lymphocyte receptors of jawless vertebrates
Authors: Mariuzza Roy A. , Velikovsky C. Alejandro , Deng Lu , Xu Gang , Pancer Zeev
Published: May 2010

Adaptive immunity in jawless vertebrates is mediated by antigen receptors that are fundamentally different from those of jawed vertebrates. Whereas antibodies and T cell receptors (TCRs) are composed of immunoglobulin (Ig) domains, the variable lymphocyte receptors (VLRs) of jawless fish consist of leucine-rich repeat (LRR) modules. As with antibodies and TCRs, VLRs are assembled by DNA recombination in a process that generates a vast repertoire of receptors. VLRs recognize as diverse an array of particulate and soluble antigens as Ig-based antibodies, and do so with similar affinity and specificity. X-ray crystallographic studies of VLRs in complex with protein and carbohydrate antigens have shown that these LRR-based receptors use nearly all their concave surface to bind ligands, in addition to a highly variable loop in their C-terminal LRR capping module. This structural information, combined with a comprehensive analysis of VLR sequences, has revealed an almost perfect match between antigen-contacting positions and positions with highest sequence diversity. The independent evolution approximately 500 million years ago of LRR-based and Ig-based receptors of comparable diversity and antigen-binding properties provides evidence for the survival value of adaptive immunity in vertebrates.
Small-angle X-ray and neutron scattering as a tool for structural systems biology
Authors: Svergun Dmitri I.
Published: May 2010

Small-angle scattering (SAS) of X-rays and neutrons reveals low-resolution structures of biological macromolecules in solution. With the recent experimental and methodological advances, SAS became a unique tool for characterising biological systems. The method covers an extremely broad range of molecule sizes (from a few kDa to hundreds of MDa) and experimental conditions (temperature, pH, salinity, ligand addition, etc.), which is of primary importance for a systemic approach in structural biology. The method provides unique information about the overall structure and conformational changes of native individual proteins, functional complexes, flexible macromolecules and hierarchical systems. New developments in small-angle X-ray and neutron scattering studies of biological macromolecules in solution are briefly reviewed, with a special emphasis on technical and methodological approaches useful for structural systems biology. Possibilities of synergistic use of the method with other techniques are considered.
Urine particle evaluation: a comparison between the UF-1000i and quantitative microscopy
Authors: Manoni Fabio , Tinello Agostino , Fornasiero Lucia , Hoffer Paolo , Temporin Valeria , Valverde Sara , Gessoni Gianluca
Published: May 2010

Background: The study of urine particles plays a key role in the diagnosis of kidney diseases. In this study, the authors evaluated the correlation between the UF-1000i and quantitative manual microscopy.

Methods: A total of 214 untreated urine samples were studied using the Sysmex UF-1000i and compared with results obtained from quantitative manual microscopy using the Fuchs-Rosenthal counting chamber.

Results: Using Pearson statistics, we observed satisfactory correlation between the UF-1000i and quantitative microscopy: for red blood cells (RBCs) r was 0.98, for white blood cells (WBCs) r was 1.00, for epithelial cells (EC) r was 0.96, and for casts r was 0.69. Using linear regression statistics, we also observed satisfactory correlation between the UF-1000i and quantitative microscopy: for RBCs R2 was 0.95, for WBCs R2 was 0.99, for EC R2 was 0.92, and for casts R2 was 0.48.

Conclusions: In our experience, automated urine particle analysis performed using the Sysmex UF-1000i analyzer is sufficiently precise and improves the workflow in a routine laboratory. Precision was satisfactory and concordance with the reference method is good for RBC, WBC and EC; for casts microscopic observation is required for flagged samples to discriminate hyaline from pathologic casts.

Clin Chem Lab Med 2010;48:1107–11.
Non-invasive fetal RHD genotyping in the first trimester of pregnancy
Authors: Cardo Leyre , García Belén Prieto , Alvarez Francisco V.
Published: May 2010

Background: Hemolytic disease of the fetus and newborn (HDN) is caused primarily by feto-maternal RhD incompatibility. Although all RhD negative pregnant women undergo routine antenatal RhD prophylaxis at 28 weeks of gestation, and following delivery if the newborn is RhD positive, HDN has not been eradicated. Here, we investigated fetal Rhesus D (RHD) genotype in maternal plasma during the first trimester of pregnancy in our area.

Methods: Plasma samples were obtained from 111 RhD negative pregnant women, between 9 and 13 weeks of gestation. DNA from maternal plasma containing cell-free fetal DNA (cffDNA) was analyzed by quantitative PCR (qPCR) to detect RHD exons 5 and 7. A β-globin (HBB) sequence was quantified to estimate total DNA concentration. qPCR results were compared with newborn RhD determined in cord blood serum. The influence of several gestational parameters on DNA concentration was also analyzed.

Results: The specificity and sensitivity of the assay was 93% and 100%, respectively, with 97% diagnostic accuracy. Cell-free DNA concentrations during the first trimester of pregnancy were not affected by the gestational parameters studied (free-β fraction of human chorionic gonadotropin and pregnancy-associated plasma protein A concentrations, fetal sex, materno-fetal ABO blood group incompatibility, maternal weight and gestational age).

Conclusions: Non-invasive fetal RHD genotyping during the first trimester of pregnancy can be determined with a high specificity, thus representing a valuable tool for improving the management of RhD negative pregnant women. As a high percentage of pregnant women participate in the routine first trimester combined screening program for aneuploidies, the fetal RHD study could be of immediate implementation, since the same blood collection could be used.

Clin Chem Lab Med 2010;48:1121–6.
Homocysteine in small-for-gestational age and appropriate-for-gestational age preterm neonates from mothers receiving folic acid supplementation
Authors: Gomes Thushari S. , Lindner Ulrike , Tennekoon Kamani H. , Karandagoda Wimal , Gortner Ludwig , Obeid Rima
Published: May 2010

Background: Prematurity and small-for-gestational age (SGA) neonates are at risk for postnatal complications. Concentrations of total homocysteine (tHcy) might be related to neonatal outcome. We hypothesized that concentrations of tHcy are not related to growth restriction in neonates from mothers receiving 5 mg/day folic acid. We studied a total of 133 preterm neonates from normotensive mothers; SGA (n=96) and appropriate-for-gestational age (AGA, n=37).

Methods: Concentrations of tHcy, folate and vitamin B12 were measured in venous umbilical cord plasma.

Results: AGA preterm neonates had higher mean birth weight (BW) compared to SGA preterms (2472 g vs. 2007 g; p<0.001) of comparable mean gestational age (GA) (35.1 vs. 35.7 weeks; p=0.059). Concentrations of tHcy (4.86 vs. 4.95 μmol/L), folate (63.3 vs. 55.7 nmol/L), and vitamin B12 (409 vs. 394 pmol/L) were not significantly different between the groups. GA was a strong positive predictor, BW was a significant negative predictor of cord plasma folate. Vitamin B12 concentration was a significant negative predictor of cord tHcy.

Conclusions: Concentrations of tHcy did not differ between SGA and AGA preterm neonates born to mothers supplemented with folic acid. This finding argues against a causal role for folate deficiency or increased tHcy in growth restriction.

Clin Chem Lab Med 2010;48:1157–61.
Blood cell and iron status analytes of preterm and full-term infants from 20 weeks onwards during the first year of life
Authors: Takala Timo I. , Mäkelä Enni , Suominen Pauli , Matomäki Jaakko , Lapinleimu Helena , Lehtonen Liisa , Rajamäki Allan , Irjala Kerttu , Lähteenmäki Päivi M.
Published: May 2010

Background:The goal of this study was to evaluate the dynamics of blood cell and iron status laboratory analytes in preterm and full-term infants during the first year of life.

Methods:This was a prospective study of 100 preterm and 50 full-term infants. Preterm infants received iron supplementation beginning at 3 weeks of age. Laboratory tests were serially analyzed up to 12 months of corrected age.

Results:Estimated means and the 95% reference intervals (RIs) from 20 weeks of age and onwards are presented separately for preterm and full-term infants. At the age of 20 weeks, mean hemoglobin (Hb) in preterm infants was lower than mean Hb in full-term infants, but this difference changed during follow-up. Ferritin concentrations were initially lower in preterm infants, but decreased to similar levels in both groups. Estimated mean values for transferrin receptor and reticulocyte Hb content were quite stable between the ages of 20 and 55 weeks in both groups.

Conclusions:Our study suggests that the same RIs for preterm and full-term infants can be used from the age of 20 or 30 weeks onwards, depending on the analyte. The RIs will help physicians detect iron deficiency or other problems of erythropoiesis in infants.

Clin Chem Lab Med 2010;48:1295–301.
Functional Neuroanatomy Supporting Judgments of When Events Occurred
Authors: Greve Andrea , Doidge Amie N. , Evans C. John , Wilding Edward L.
Published: May 2010

The neural substrates of memory for when events occurred are not well described. One reason for this is that the paradigms used to date have permitted isolation of only some of the relevant memory processes. In this experiment, functional magnetic resonance imaging was used to identify for the first time brain regions that support two distinct bases upon which “when” judgments can be made. Seventeen human participants (6 male) completed a continuous recognition memory task where the interval between presentation and re-presentation of words varied between 5 and 25 intervening words (the lag). The task on each trial was to distinguish repeated words from those presented for the first time, and to indicate the lag for repeated words. The inferior parietal lobe showed greater activation for shorter lag judgments, regardless of judgment accuracy. The lingual gyrus, by contrast, was more active for correct than for incorrect lag judgments, regardless of the interval between first and second item presentations. Both of these regions have been linked in previous work to the process of recollection, and the findings described here represent a novel neural dissociation across regions that deploy mnemonic information in fundamentally different ways to support judgments about when events occurred.
Control of Extracellular Dopamine at Dendrite and Axon Terminals
Authors: Ford Christopher P. , Gantz Stephanie C. , Phillips Paul E. M. , Williams John T.
Published: May 2010

Midbrain dopamine neurons release dopamine from both axons and dendrites. The mechanism underlying release at these different sites has been proposed to differ. This study used electrochemical and electrophysiological methods to compare the time course and calcium dependence of somatodendritic dopamine release in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc) to that of axonal dopamine release in the dorsal striatum. The amount of dopamine released in the striatum was ∼20-fold greater than in cell body regions of the VTA or SNc. However, the calcium dependence and time to peak of the dopamine transients were similar. These results illustrate an unexpected overall similarity in the mechanisms of dopamine release in the striatum and cell body regions. To examine how diffusion regulates the time course of dopamine following release, dextran was added to the extracellular solution to slow diffusion. In the VTA, dextran slowed the rate of rise and fall of the extracellular dopamine transient as measured by fast-scan cyclic voltammetry yet did not alter the kinetics of the dopamine-dependent IPSC. Dextran failed to significantly alter the time course of the rise and fall of the dopamine transient in the striatum, suggesting a more influential role for reuptake in the striatum. The conclusion is that the time course of dopamine within the extracellular space of the VTA is dependent on both diffusion and reuptake, whereas the activation of D2receptors on dopamine neurons is primarily limited by reuptake.
V1 Interpatch Projections to V2 Thick Stripes and Pale Stripes
Authors: Sincich Lawrence C. , Jocson Cristina M. , Horton Jonathan C.
Published: May 2010

Cytochrome oxidase (CO) reveals two compartments in V1 (patches and interpatches) and three compartments in V2 (thin, pale, and thick stripes). Previously, it was shown that thin stripes receive input predominantly from patches. Here we examined the projections to thick and pale stripes in macaques, revealed by retrograde tracer injections. After thick stripe injection, cells were distributed in layer 2/3 (67%), layer 4A (7%), layer 4B (23%), and layer 5/6 (2%). Except in layer 5/6, cells were concentrated in interpatches, with a stronger bias in layer 2/3 (84%) than in layer 4B (75%). After pale stripe injection, cells were found in layer 2/3 (87%), layer 4A (2%), layer 4B (10%), and layer 5/6 (2%). As for thick stripes, cells were located preferentially in interpatches in layer 2/3 (84%) and layer 4B (72%) but not in layer 5/6. Thick stripes received a higher proportion of their input from layer 4B, compared with pale stripes, consistent with reports that thick stripe neurons exhibit a pronounced layer 4B influence. This difference aside, both stripe types receive similar inputs from V1, at least in terms of cortical layer and CO compartment. This finding was bolstered by injecting different tracers into pale and thick stripes; 10–27% of cells were double labeled, with most located in interpatches. These results suggest that the distinctive receptive field properties of neurons in thick and pale stripes are generated by local V2 circuits, or by other specific projections, rather than by differing sources of laminar and compartmental input from V1.
Cell-Produced α-Synuclein Is Secreted in a Calcium-Dependent Manner by Exosomes and Impacts Neuronal Survival
Authors: Emmanouilidou Evangelia , Melachroinou Katerina , Roumeliotis Theodoros , Garbis Spiros D. , Ntzouni Maria , Margaritis Lukas H. , Stefanis Leonidas , Vekrellis Kostas
Published: May 2010

α-Synuclein is central in Parkinson's disease pathogenesis. Although initially α-synuclein was considered a purely intracellular protein, recent data suggest that it can be detected in the plasma and CSF of humans and in the culture media of neuronal cells. To address a role of secreted α-synuclein in neuronal homeostasis, we have generated wild-type α-synuclein and β-galactosidase inducible SH-SY5Y cells. Soluble oligomeric and monomeric species of α-synuclein are readily detected in the conditioned media (CM) of these cells at concentrations similar to those observed in human CSF. We have found that, in this model, α-synuclein is secreted by externalized vesicles in a calcium-dependent manner. Electron microscopy and liquid chromatography–mass spectrometry proteomic analysis demonstrate that these vesicles have the characteristic hallmarks of exosomes, secreted intraluminar vesicles of multivesicular bodies. Application of CM containing secreted α-synuclein causes cell death of recipient neuronal cells, which can be reversed after α-synuclein immunodepletion from the CM. High- and low-molecular-weight α-synuclein species, isolated from this CM, significantly decrease cell viability. Importantly, treatment of the CM with oligomer-interfering compounds before application rescues the recipient neuronal cells from the observed toxicity. Our results show for the first time that cell-produced α-synuclein is secreted via an exosomal, calcium-dependent mechanism and suggest that α-synuclein secretion serves to amplify and propagate Parkinson's disease-related pathology.
Interactions between Stimulus-Specific Adaptation and Visual Auditory Integration in the Forebrain of the Barn Owl
Authors: Reches Amit , Netser Shai , Gutfreund Yoram
Published: May 2010

Neural adaptation and visual auditory integration are two well studied and common phenomena in the brain, yet little is known about the interaction between them. In the present study, we investigated a visual forebrain area in barn owls, the entopallium (E), which has been shown recently to encompass auditory responses as well. Responses of neurons to sequences of visual, auditory, and bimodal (visual and auditory together) events were analyzed. Sequences comprised two stimuli, one with a low probability of occurrence and the other with a high probability. Neurons in the E tended to respond more strongly to low probability visual stimuli than to high probability stimuli. Such a phenomenon is known as stimulus-specific adaptation (SSA) and is considered to be a neural correlate of change detection. Responses to the corresponding auditory sequences did not reveal an equivalent tendency. Interestingly, however, SSA to bimodal events was stronger than to visual events alone. This enhancement was apparent when the visual and auditory stimuli were presented from matching locations in space (congruent) but not when the bimodal stimuli were spatially incongruent. These findings suggest that the ongoing task of detecting unexpected events can benefit from the integration of visual and auditory information.
Developmental Origin of the Neuronal Subtypes That Comprise the Amygdalar Fear Circuit in the Mouse
Authors: Waclaw Ronald R. , Ehrman Lisa A. , Pierani Alessandra , Campbell Kenneth
Published: May 2010

We have taken a genetic-based fate-mapping approach to determine the specific contributions of telencephalic progenitors to the structures that comprise the amygdalar fear circuit including the central (CA), lateral (LA), and basolateral (BLA) amygdala. Our data indicate that progenitors in the ventral pallium (VP) contribute projection neurons to the LA and BLA but not the CA. Rather, the CA appears to derive, at least in part, from progenitors located in the ventral lateral ganglionic eminence (vLGE). Diverse groups of interneurons populate these amygdalar nuclei, and as predicted our data support the notion that they originate from subpallial progenitors. A rather specific population of amygdalar interneurons, the intercalated cells (ITCs), is known to play a fundamental role in fear-related behaviors. However, no information on their specific origin has, as yet, been provided. Our findings suggest that the ITCs arise from the dorsal lateral ganglionic eminence (dLGE) and migrate in the lateral migratory stream to populate the paracapsular regions as well as the main intercalated mass of the amygdala (IA). Germ-lineGsx2mutants are known to exhibit an expansion of the VP into the LGE and a concomitant reduction in the dLGE and vLGE. Accordingly,Gsx2conditional mutants display a significantly enlarged LA and a significant reduction in ITCs both within the paracapsular regions and the IA. Additional support for a dLGE origin of the ITCs was obtained in conditional mutants of the dLGE geneSp8. Thus, our findings indicate diverse origins for the neuronal components that comprise the amygdalar fear circuit.
Orbitofrontal Cortex Lesions Alter Anxiety-Related Activity in the Primate Bed Nucleus of Stria Terminalis
Authors: Fox Andrew S. , Shelton Steven E. , Oakes Terrence R. , Converse Alexander K. , Davidson Richard J. , Kalin Ned H.
Published: May 2010

In children, behavioral inhibition (BI) in response to potential threat predicts the development of anxiety and affective disorders, and primate lesion studies suggest involvement of the orbitofrontal cortex (OFC) in mediating BI. Lesion studies are essential for establishing causality in brain–behavior relationships, but should be interpreted cautiously because the impact of a discrete lesion on a complex neural circuit extends beyond the lesion location. Complementary functional imaging methods assessing how lesions influence other parts of the circuit can aid in precisely understanding how lesions affect behavior. Using this combination of approaches in monkeys, we found that OFC lesions concomitantly alter BI and metabolism in the bed nucleus of stria terminalis (BNST) region and that individual differences in BNST activity predict BI. Thus it appears that an important function of the OFC in response to threat is to modulate the BNST, which may more directly influence the expression of BI.
John Coltrane and the “replacement child” syndrome
Authors: Lauer Bertrand
Published: May 2010

John Coltrane is a singular character: few musicians have developed such a creative, dense and dazzling career. He is also singular in the obsessive, almost manic way he is said to have practiced his instrument all his life. Singular indeed, if we consider his evolution from self-destructiveness to rebirth, through the Born Again doctrine. He stands as an enigmatic, mythological even messianic figure among music lovers and those who played with him. The purpose of this article is to demonstrate that the saxophonist’s development was conditioned by his being a “replacement child”, as it was the case for Vincent Van Gogh, Salvador Dali, Ludwig van Beethoven, Chateaubriand, Camille Claudel, Stendhal .
The Dilemmas of African-American Orientalism
Authors: Parent Emmanuel , Tosser Grégoire
Published: May 2010

Through the analysis of John Coltrane’s‘Olé’, this paper examines the artist’s treatment of the Hispanic imaginary with musicological aspects as well as anthropological considerations, and suggests that the work lies within a double framework. The first framework is African-American, with the multiplication of works of jazz that has mobilized the Spanish musical universe since the mid-fifties. The second is European, with the long Western tradition of Spanish orientalism that flourished in the XIXth century. The central purpose will thus be to examine what type of Orientalism Coltrane suggests to us. In their confrontation with the Hispanic imaginary, do Coltrane and his musicians attempt to foreground roots or otherness, empathy or conflict? Despite a genuine experimental treatment that allows him to transcend a mere Spanish exoticism, and a commitment to the politics of Black cultural nationalism in the 1960’s, we argue that Coltrane’s brand of orientalism is not that different from his European avant-garde counterparts’. In other words, John Coltrane does not totally get rid of a common staple element in classical Orientalism: the essentialisation of pre-modern cultures.
Sampling Kimberly Benston's 'Coltrane Poem'
Authors: Raynaud Claudine
Published: May 2010

At the height of the Civil Rights Movement, John Coltrane became a major African American cultural icon whose magisterial 1964 A Love Supreme acted as a model for black artists infused with the spirit of the Black Arts Movement. In his study of black modernism, Performing Blackness (2000), literary critic Kimberly Benston defines the numerous poems dedicated to the musician as a distinct genre, that of the ‘Coltrane Poem.’ A close reading of three major texts by Jane Cortez, Sonia Sanchez and Michael Harper illustrates how the poetry of the black aesthetics raises jazz music to the rank of the ultimate medium of interrogation, transgression and innovation that poetry itself in turn incarnates. After Coltrane’s disappearance in 1967, black poets construct an elegiac mode by revisiting the myth of Black Orpheus from dismemberment to resurrection. Poetry is performance, immediacy, and presence, to the point of letting the voice alone bear the burden of a vanishing text. The violent political context of the sixties, the avant-garde desire to disrupt barriers between music and words and the impact of Coltrane’s conversion in 1957, account for the revolutionary character of these texts. ‘Coltrane’ is not the ‘subject’ of a meditation. His radically new approach to jazz and his genius for improvisation–he also wrote poems that he incorporated into his music–inhabit a questioning of the form itself and of the nature of art as a medium, often at the peril of the word and at the risk of meaning. Elegy and eulogy are as many fighting modes on the battlefield of sound and voice, faced with death, chaos and silence, but full with the promise of transcendence.
Distribuição do sistema radicular da cana de açúcar var. co. 290, em solo tipo terra-roxa-legítima
Authors: Inforzato Romeu , Alvarez Raphael
Published: May 2010

No presente trabalho são apresentados os resultados obtidos no estudo do sistema radicular da cana de açúcar var. Co. 290, sob condições normais de cultivo em terra-roxa-legítima, na Usina Tamôio, município de Araraquara e em três idades: seis, doze e dezoito meses. Empregou-se o mesmo método já utilizado para o cafeeiro, com as alterações convenientes à cana de açúcar. Os resultados mostraram que a distribuição do sistema radicular da variedade estudada se apresentou bem homogênea nas diferentes camadas de solo, sendo que o maior adensamento se deu nos primeiros 30 cm com uma média, nas três idades, de 59,3%. Observou-se que aos seis meses as raízes iam além de 2,10m de profundidade, para atingir 3,30 m na planta adulta. O máximo de raízes vivas foi encontrado aos 12 meses, período de intenso crescimento da planta. Calculou-se a quantidade de raízes que essa cultura deixa incorporada ao solo, após o corte. Para uma produção de 100 toneladas de cana por hectare a planta, aos seis meses, já fornece 1,8 toneladas de raízes nessa mesma área, atingindo a 8 toneladas na planta adulta.
Comportamento de variedades de cana de açúcar no arenito de Bauru
Authors: Segalla A. L. , Alvarez R.
Published: May 2010

Neste trabalho são apresentados os resultados obtidos em um ensaio de variedades de cana de açúcar, realizado a partir de 1952 na Usina Miranda, no município de Presidente Alves. A finalidade do ensaio foi determinar as melhores variedades de cana existentes na ocasião, para os solos do Arenito Bauru, completando estudos iniciados no ano anterior em outros tipos de solo. Foram estudadas 16 variedades: Co.290, Co.413, Co.419, Co.421, C.B.36/14, C.B.40/19, C.B.40/69, C.B. 40/77, C.B.41/18, C.B.41/61, C.B.41/70, C.P.27/139, C.P.29/291, I.A.C.34/536, I.A.C. 34/553 e P.O.J.2961. Fizeram-se três cortes, cana-planta, soca e ressoca, sendo analisadas as produções de cana e de açúcar provável do primeiro corte e dos totais dos três cortes. Os resultados obtidos indicaram que podem ser cultivadas naquela região as variedades: Co.419, C.B.40/69, C.B.40/77, C.B.41/61, Co.290 e C.B.41/70. A Co.421, apesar de produtiva, apresenta alguns inconvenientes. São feitas restrições às variedades C.B.36/14, C.B.41/18, C.P.27/139 e C.P.29/291, esta suscetível ao carvão da cana. As outras variedades estudadas não são recomendáveis, devido às baixas produções apresentadas.
Lixiviação do B. H. C. (isômero gama) em solo tipo arenito Bauru
Authors: Gargantini H. , Giannotti O. , Tella Romeu de
Published: May 2010

No presente trabalho são descritos os resultados obtidos em um experimento sobre determinação da lixiviação do B. H. C. em solo tipo arenito Bauru. Foram utilizados lisímetros monolíticos com estrutura indeformável, que receberam certa quantidade de B.H.C, e água destilada. Tôda a água percolada foi dosada em seu teor em B. H. C. Posteriormente os lisímetros foram abertos e também pesquisado o B. H. C. no solo, a diferentes profundidades. Pelos resultados obtidos verificou-se que, nas condições da experiência, o B. H. C. (isômero gama) não é arrastado em profundidade, ficando retidos nos primeiros 10 cm de solo praticamente 90% do B. H. C. colocado na parte superior.
O uso de substâncias inibidoras da brotação de tubérculos de batatinha
Authors: Boock O. J.
Published: May 2010

A conservação de tubérculos de batatinha para o consumo vem preocupando os pesquisadores em diferentes países, por se tratar de um produto fácilmente perecível. Além dos trabalhos sôbre frigorificação, já bem conhecidos, iniciou-se o emprêgo de substâncias químicas inibidoras da brotação e que impedem as podridões causadas por Fusarium. Dentre essas drogas sobressairam-se o éster metílico do ácido alfanaftaleno acético e o tetracloronitrobenzeno. Os resultados alcançados, embora contraditórios em alguns pontos, vieram demonstrar a viabilidade do seu uso, principalmente em países onde o inverno é rigoroso. Das experiências e observações feitas no Instituto Agronômico de Campinas a partir de 1946, chegou-se à conclusão que as referidas drogas somente trouxeram bons resultados quando os tubérculos tratados foram conservados a baixa temperatura (4°C). Por outro lado, as batatinhas armazenadas a essa temperatura tornaram-se adocicadas e de má aceitação pelos consumidores, devido à formação de açúcares. Mantendo-se as temperaturas entre 18 e 26°C não houve, na maioria dos casos, influência nítida das drogas sôbre a redução da brotação, constatando--se, ao contrário, um aumento na porcentagem de tubérculos deteriorados devido à podridão mole causada por bactérias.