bluuebunny/crossref_metadata_2025 huggingface dataset:
Amphetamine reduces vesicular dopamine content in dexamethasone‐differentiated PC12 cells only following l‐DOPA exposure
Authors: Hondebrink Laura , Meulenbelt Jan , Timmerman Johan G. , Van Den Berg Martin , Westerink Remco H. S.
Published: August 2009

Amphetamine (AMPH) increases brain dopamine (DA) levels via reversal of the membrane DA transporter. Additional mechanisms have been suggested, including inhibition of vesicular monoamine transporters and vesicular leakage of DA and Ca2+. According to the widely‐accepted weak base theory, AMPH disrupts the proton gradient required for filling vesicles with DA. As a result, DA and Ca2+ will leak from vesicles, giving rise to exocytosis of less‐filled vesicles. As several contradictions have been described, the aim of the present study was to re‐examine this theory using amperometry and Fura‐2 imaging to measure AMPH‐induced changes in exocytosis and intracellular Ca2+ levels, respectively, in PC12 and chromaffin cells. Unexpectedly, 15 min exposure to AMPH (20–200 μM) does not affect the amount of DA released per vesicle, the frequency of exocytosis or intracellular Ca2+ levels in PC12 cells or chromaffin cells. Comparable results were found following prolonged exposure to AMPH (45 min) or at 37°C. When cells were pre‐treated with the DA precursor l‐DOPA, vesicle content increased to ∼150%. When these pre‐treated cells are exposed to AMPH, vesicle content is strongly reduced. These results indicate that in dexamethasone‐differentiated PC12 cells AMPH‐induced vesicle leakage occurs only under specific conditions, therefore arguing for re‐evaluation of the theory of AMPH‐induced vesicular DA leakage.
Assessment of Left Ventricular Function and Tei Index by Tissue Doppler Imaging in Patients with Slow Coronary Flow
Authors: Baykan Merih , Baykan Emre Cumhur , Turan Salih , Gedikli Ömer , Kaplan Şahin , Kırış Abdulkadir , Durmuş Ismet , Çelik Şükrü
Published: August 2009

Background: The aim of this study was to assess left ventricular (LV) function and the Tei index by tissue Doppler imaging (TDI), and also to evaluate the relationship of thrombolysis in myocardial infarction (TIMI) frame count (TFC) with the Tei index and LV function in patients with slow coronary flow (SCF). Methods: We prospectively evaluated 50 patients with SCF and 27 control subjects. Diagnosis of SCF was made by TFC. LV systolic and diastolic function was assessed by conventional echocardiography and TDI. Results: Early diastolic mitral annular velocity (Em), Em/Am, and peak systolic mitral annular velocity (Sm) were lower in patients with SCF than those in controls (13±2.8 cm/sec vs 15.2±2.8 cm/sec, P = 0.002; 0.88±0.22 vs 1±0.23, P = 0.03; and 14.1±3.51 vs 16.5±3.31, P = 0.005, respectively). In patients with SCF, the Tei index was significantly higher than that in controls (0.34±9.6 vs 0.29±9.5, P = 0.02, respectively). Mean TFC and RCA TFC were positively correlated with the Tei index (r = 0.3, P = 0.02 and r = 0.329, P = 0.02). Left circumflex (LCX) TFC was negatively correlated with Em/Am (r =–0.310, P = 0.03) only in patients with SCF. Conclusion: LV systolic and diastolic function is impaired in patients with SCF. TDI analysis of mitral annular velocities such as the Tei index, Em, Em/Am, and Sm is useful to assess LV systolic and diastolic dysfunction in patients with SCF. Mean TFC and RCA TFC were positively correlated with the Tei index and LCX TFC was negatively correlated with Em/Am. TDI may be better than conventional echocardiography in assessing LV function in patients with SCF. (ECHOCARDIOGRAPHY, Volume 26, November 2009)
A Role for the Karyopherin Kap123p in Microtubule Stability
Authors: Ptak Christopher , Anderson Andrea M. , Scott Robert J. , Van de Vosse David , Rogers Richard S. , Sydorskyy Yaroslav , Aitchison John D. , Wozniak Richard W.
Published: August 2009

Several components of the nuclear transport machinery play a role in mitotic spindle assembly in higher eukaryotes. To further investigate the role of this family of proteins in microtubule function, we screened for mutations in Saccharomyces cerevisiae that confer sensitivity to microtubule‐destabilizing drugs. One mutant exhibiting this phenotype lacked the gene encoding the karyopherin Kap123p. Analysis of kap123Δ cells revealed that the drug sensitivity was caused by a defect in microtubule stability and/or assembly. In support of this idea, we demonstrated genetic interactions between the kap123Δ mutation and mutated alleles of genes encoding α‐tubulins and factors controlling microtubule dynamics. Moreover, kap123Δ cells exhibit defects in spindle structure and dynamics as well as nuclear positioning defects during mitosis. Cultures of kap123Δ strains are enriched for mononucleated large‐budded cells often containing short spindles and nuclei positioned away from the budneck, phenotypes indicative of defects in both cytoplasmic and nuclear microtubules. Finally, we identified a gene, CAJ1, which when deleted in combination with KAP123 exacerbated the microtubule‐related defects of the kap123Δ mutants. We propose that Kap123p and Caj1p, a member of the Hsp40 family of proteins, together play an essential role in normal microtubule function.
Temperature mediates vector transmission efficiency: inoculum supply and plant infection dynamics
Authors: Daugherty M.P. , Bosco D. , Almeida R.P.P.
Published: August 2009

Climate, particularly environmental temperature, frequently plays an important role in disease epidemiology. This study investigated the role of environmental temperature on transmission of the generalist plant pathogen Xylella fastidiosa by its leafhopper vectors. In this system temperature is known to influence both vector performance and feeding rate, yet the implications for pathogen transmission have not been documented. Experiments were conducted over a range of temperatures to document effects on transmission efficiency of the California native Graphocephala atropunctata (blue–green sharpshooter) and the invasive Homalodisca vitripennis (glassy‐winged sharpshooter). Inoculation efficiency of H. vitripennis was positively related to temperature. Graphocephala atropunctata mortality and transmission responded non‐linearly to temperature, with the highest rates of both at the highest temperature. The experiment also evaluated whether differences in inoculum supply contributed to plant infection level using quantitative PCR. Although total X. fastidiosa population within G. atropunctata was not related to plant infection, the number of infectious vectors was a strong predictor of plant infection level–suggesting that the number of inoculation events is important in the development of systemic infection of X. fastidiosa in grapevines. These results, along with existing evidence from the literature, point to wide‐ranging impacts of climate on the epidemiology of X. fastidiosa diseases.
Taste and Objectivity: The Emergence of the Concept of the Aesthetic
Authors: Schellekens Elisabeth
Published: August 2009

Can there be a philosophy of taste? This paper opens by raising some metaphilosophical questions about the study of taste – what it consists of and what method we should adopt in pursuing it. It is suggested that the best starting point for philosophising about taste is against the background of 18th‐century epistemology and philosophy of mind, and the conceptual tools this new philosophical paradigm entails. The notion of aesthetic taste in particular, which emerges from a growing sense of dissatisfaction with an undifferentiated category of taste, comes to be set apart from gustatory taste on account of its normativity and aspirations to objectivity. The paradox of taste, as found in Hume and Kant, is examined, and shown to be highly relevant to contemporary metaphysical debate within aesthetics. Specifically, this paper argues that both Realists and Anti‐Realists rely more heavily than assumed on the idea of taste.
Disagreement as Evidence: The Epistemology of Controversy
Authors: Christensen David
Published: August 2009

How much should your confidence in your beliefs be shaken when you learn that others – perhaps ‘epistemic peers’ who seem as well‐qualified as you are – hold beliefs contrary to yours? This article describes motivations that push different philosophers towards opposite answers to this question. It identifies a key theoretical principle that divides current writers on the epistemology of disagreement. It then examines arguments bearing on that principle, and on the wider issue. It ends by describing some outstanding questions that thinking about this issue raises.
Emergence in Physics
Authors: Wayne Andrew , Arciszewski Michal
Published: August 2009

This paper begins by tracing interest in emergence in physics to the work of condensed matter physicist Philip Anderson. It provides a selective introduction to contemporary philosophical approaches to emergence. It surveys two exciting areas of current work that give good reason to re‐evaluate our views about emergence in physics. One area focuses on physical systems wherein fundamental theories appear to break down. The other area is the quantum‐to‐classical transition, where some have claimed that a complete explanation of the behaviors and features of the objects of classical physics entirely in quantum terms is now within our grasp. We suggest that the most useful way to approach the emergent/non‐emergent distinction is in epistemic terms, and more specifically that the failure of reductive explanation is constitutive of emergence in physics.
Longevity and Optimal Health
Authors: Oz Mehmet , Tallent Jeremy
Published: August 2009

Efforts to foster a research dialogue between traditions as seemingly divergent as Western biomedicine and Indo‐Tibetan medical and self‐regulatory practice require a carefully conceived set of methodological guidelines. To approach a useful methodology, some specific structural differences between traditions must be negotiated, for example the Indo‐Tibetan emphasis on holism in medicine and ethics, which appears to run contrary to Western trends toward specialization in both clinical and research contexts. Certain pitfalls must be avoided as well, including the tendency to appropriate elements of either tradition in a reductionistic manner. However, research methods offering creative solutions to these problems are now emerging, successfully engendering quantitative insight without subsuming one tradition within the terms of the other. Only through continued, creative work exploring both the potentials and limitations of this dialogue can collaborative research insight be attained, and an appropriate and useful set of methodological principles be approached.
Culture and Development of Self‐Regulation
Authors: Trommsdorff Gisela
Published: August 2009

In the present paper, I aim to both contribute to a culture‐based theory of self‐regulation and clarify some mutually constitutive functions of psychological and sociocultural phenomena. I examine the relations between self and culture and the role of these relations in the development of self‐regulation. Self‐regulation is based on the intention to modify internal processes and behavior to reach one’s goals. Because the development of self‐regulation is embedded in a cultural context that gives priority to a specific model of agency, processes of self‐regulation are assumed to differ cross‐culturally. First, I give a brief overview on self‐regulation research. Further, I discuss the contribution of a culture‐informed perspective to the study of self‐regulation and its development, taking into account interpersonal self‐regulation. Finally, I present a ‘Cultural Model of Agency and Self‐Regulation,’ which suggests how to link culture and individual agency.
Interesting Things and Curious People: Exploration and Engagement as Transient States and Enduring Strengths
Authors: Silvia Paul J. , Kashdan Todd B.
Published: August 2009

Curiosity, interest, and intrinsic motivation are critical to the development of competence, knowledge, and expertise. Without a mechanism of intrinsic motivation, people would rarely explore new things, learn for its own sake, or engage with uncertain tasks despite feelings of confusion and anxiety. This article explores two sides of interest: momentary feelings (the emotion of interest) and enduring traits (the character strength of curiosity). Recent theories in emotion psychology can explain why and when people experience feelings of interest; recent research has illuminated the role of curiosity in cultivating knowledge, meaning in life, close relationships, and physical and mental resilience. The problem for future research – and for social and personality psychology more generally – is how to bridge the dynamics of everyday experience with stable, lifespan aspects of personality.
Anxiety: Proximate Processes and Ultimate Functions
Authors: Maner Jon K.
Published: August 2009

Anxiety is a universal feature of human existence. Anxiety is associated with a range of cognitive processes such as attention to threat, appraisals of uncertainty and lack of control, pessimistic judgments, and risk‐avoidant decision making. The current paper presents a framework for understanding these processes as a set of domain‐specific mechanisms designed to face specific challenges encountered by humans throughout evolutionary history (e.g., avoiding forms of physical harm and contagious disease, maintaining social acceptance and close romantic relationships, and navigating status hierarchies). Anxiety involves a functionally organized constellation of adaptive processes designed to help people face recurrent psychological, social, and physical threats. The integration of psychological and evolutionary perspectives provides a basis for understanding anxiety’s proximate processes, as well as its underlying adaptive functions.
Hierarchies in the Structure of Personality Traits
Authors: Markon Kristian E.
Published: August 2009

An emerging body of findings indicates that hierarchy is critical to integrating the Big Trait models – the Big Five, Big Four, Big Three, and Big Two – within a common structural framework. These findings, in addition to providing a unifying framework for understanding personality traits, confirm that hierarchy is an intrinsic and pervasive feature of trait structure. Here, fundamental concepts of trait hierarchies are reviewed, as is the empirical literature about hierarchies in personality trait structure. Important questions remain to be answered about the nature and form of hierarchies found in trait structure, as well as the methods used to understand them.
Hijab and the Abrahamic Traditions: A Comparative Analysis of the Muslim Veil
Authors: Ternikar Farha
Published: August 2009

Modesty is a common theme in the Abrahamic traditions of Islam, Christianity and Judaism. Although modesty norms are largely based in religious scripture, the form in which they play out is largely shaped by cultural norms and social factors. This essay explores how Muslim women in North America negotiate modesty norms by exploring cross‐cultural research on veiling, highlighting the differences and similarities these women share with their Christian and Jewish counterparts. Research suggests that Muslim women’s modesty norms are contingent on culture, socioeconomic status, geopolitical factors, race and religiosity.
The Actuarial Assessment and Experiential Reality of Risk in Childhood
Authors: Madge Nicola
Published: August 2009

All children face risks in their everyday lives, although some experience more than others. Age, gender, geography and relative disadvantage are among the factors making a difference. Assessing and managing these risks has generated enormous academic interest, political activity, public debate, and emotion, but a major tension has arisen. This is between the actuarial models of risk assessment widely advocated and imposed by agencies including the government, even if prompted by individual instance and public outrage, and experiential models of risk assessment commonly adopted by children and their families. This gives rise to the issue of whether children should be protected at all cost because of the risk from both visible and hidden dangers, or whether they should be exposed to challenge and adventure to allow them to learn to assess and manage risk for themselves. It is unclear whether or not the world is a safer place for children than in the past, and it is apparent that risks constantly change. The challenge is to ensure that young people remain safe while at the same time gaining opportunities to experience excitement and develop their independence.
Cardiomyocyte enlargement, proliferation and maturation during chronic fetal anaemia in sheep
Authors: Jonker Sonnet S. , Giraud M. Kathryn , Giraud George D. , Chattergoon Natasha N. , Louey Samantha , Davis Lowell E. , Faber J. Job , Thornburg Kent L.
Published: August 2009

Chronic anaemia increases the workload of the growing fetal heart, leading to cardiac enlargement. To determine which cellular process increases cardiac mass, we measured cardiomyocyte sizes, binucleation as an index of terminal differentiation, and tissue volume fractions in hearts from control and anaemic fetal sheep. Fourteen chronically catheterized fetal sheep at 129 days gestation had blood withdrawn for 9 days to cause severe anaemia; 14 control fetuses were of similar age. At postmortem examination, hearts were either enzymatically dissociated or fixed for morphometric analysis. Daily isovolumetric haemorrhage reduced fetal haematocrit from a baseline value of 35% to 15% on the final day (P < 0.001). At the study conclusion, anaemic fetuses had lower arterial pressures than control fetuses (P < 0.05). Heart weights were increased by 39% in anaemic fetuses compared with control hearts (P < 0.0001), although the groups had similar body weights; the heart weight difference was not due to increased ventricular wall water content or disproportionate non‐myocyte tissue expansion. Cardiomyocytes from anaemic fetuses tended to be larger than those of control fetuses. There were no statistically significant differences between groups in the cardiomyocyte cell cycle activity. The degree of terminal differentiation was greater in the right ventricle of anaemic compared with control fetuses by ∼8% (P < 0.05). Anaemia substantially increased heart weight in fetal sheep. The volume proportions of connective and vascular tissue were unchanged. Cardiomyocyte mass expanded by a balanced combination of cellular enlargement, increased terminal differentiation and accelerated proliferation.
Determination of the quality index for photon beams at arbitrary field sizes
Authors: Sauer Otto A.
Published: August 2009

Purpose:

A commonly used beam quality index for high‐energy photon beams is the tissue phantom ratio for a square field of and SDD of . On some specialized radiotherapy treatment equipment such a reference collimator setting is not achievable. Likewise a flat beam profile, not explicitly required in dosimetry protocols, but certainly influences the measurement of , is not always produced. In this work, a method was developed in order to determine at any field size, especially for small and nonflattened beams.

Methods:

An analytical relationship was derived between for arbitrary field sizes and [the ] as quality index. The proposed model equation was fitted to the measured and published data in order to achieve three general fit parameters. The procedure was then tested with published data from TomoTherapy and CyperKnife treatment devices.

Results:

For standard flattened photon fields, the uncertainty in measured at any field size using the parameters derived from this study is better than 1%. In flattening‐filter free beams, the proposed procedure results in a reliable for any field size setting.

Conclusions:

A method is introduced and successfully tested in order to measure the beam quality under nonstandard conditions. It can be used, e.g., to get energy dependent correction factors as tabulated in dosimetry codes of practice even if standard conditions are not adjustable.
Biphenyl-Metabolizing Bacteria in the Rhizosphere of Horseradish and Bulk Soil Contaminated by Polychlorinated Biphenyls as Revealed by Stable Isotope Probing
Authors: Uhlik Ondrej , Jecna Katerina , Mackova Martina , Vlcek Cestmir , Hroudova Miluse , Demnerova Katerina , Paces Vaclav , Macek Tomas
Published: August 2009

DNA-based stable isotope probing in combination with terminal restriction fragment length polymorphism was used in order to identify members of the microbial community that metabolize biphenyl in the rhizosphere of horseradish (
Armoracia rusticana
) cultivated in soil contaminated with polychlorinated biphenyls (PCBs) compared to members of the microbial community in initial, uncultivated bulk soil. On the basis of early and recurrent detection of their 16S rRNA genes in clone libraries constructed from [
13
C]DNA,
Hydrogenophaga
spp. appeared to dominate biphenyl catabolism in the horseradish rhizosphere soil, whereas
Paenibacillus
spp. were the predominant biphenyl-utilizing bacteria in the initial bulk soil. Other bacteria found to derive carbon from biphenyl in this nutrient-amended microcosm-based study belonged mostly to the class
Betaproteobacteria
and were identified as
Achromobacter
spp.,
Variovorax
spp.,
Methylovorus
spp., or
Methylophilus
spp. Some bacteria that were unclassified at the genus level were also detected, and these bacteria may be members of undescribed genera. The deduced amino acid sequences of the biphenyl dioxygenase α subunits (BphA) from bacteria that incorporated [
13
C]into DNA in 3-day incubations of the soils with [
13
C]biphenyl are almost identical to that of
Pseudomonas alcaligenes
B-357. This suggests that the spectrum of the PCB congeners that can be degraded by these enzymes may be similar to that of strain B-357. These results demonstrate that altering the soil environment can result in the participation of different bacteria in the metabolism of biphenyl.
Cloning of
Salmonella enterica
Serovar Enteritidis Fimbrial Protein SefA as a Surface Protein in
Escherichia coli
Confers the Ability To Attach to Eukaryotic Cell Lines
Authors: Rank Douglas L. , Saeed Mahdi A. , Muriana Peter M.
Published: August 2009

The gene for the
Salmonella enterica
serovar Enteritidis fimbrial protein SefA was cloned into an
Escherichia coli
surface expression vector and confirmed by Western blot assay.
E. coli
clones expressing SefA attached to avian ovary granulosa cells and HEp-2 cells, providing evidence for the involvement of SefA in the ability of
Salmonella
to attach to eukaryotic cells.
Response of Gut Microbiota to Fasting and Hibernation in Syrian Hamsters
Authors: Sonoyama Kei , Fujiwara Reiko , Takemura Naoki , Ogasawara Toru , Watanabe Jun , Ito Hiroyuki , Morita Tatsuya
Published: August 2009

Although hibernating mammals wake occasionally to eat during torpor, this period represents a state of fasting. Fasting is known to alter the gut microbiota in nonhibernating mammals; therefore, hibernation may also affect the gut microbiota. However, there are few reports of gut microbiota in hibernating mammals. The present study aimed to compare the gut microbiota in hibernating torpid Syrian hamsters with that in active counterparts by using culture-independent analyses. Hamsters were allocated to either torpid, fed active, or fasted active groups. Hibernation was successfully induced by maintaining darkness at 4°C. Flow cytometry analysis of cecal bacteria showed that 96-h fasting reduced the total gut bacteria. This period of fasting also reduced the concentrations of short chain fatty acids in the cecal contents. In contrast, total bacterial numbers and concentrations of short chain fatty acids were unaffected by hibernation. Denaturing gradient gel electrophoresis of PCR-amplified 16S rRNA gene fragments indicated that fasting and hibernation modulated the cecal microbiota. Analysis of 16S rRNA clone library and species-specific real-time quantitative PCR showed that the class
Clostridia
predominated in both active and torpid hamsters and that populations of
Akkermansia muciniphila
, a mucin degrader, were increased by fasting but not by hibernation. From these results, we conclude that the gut microbiota responds differently to fasting and hibernation in Syrian hamsters.
Comprehensive Census of Bacteria in Clean Rooms by Using DNA Microarray and Cloning Methods
Authors: La Duc Myron T. , Osman Shariff , Vaishampayan Parag , Piceno Yvette , Andersen Gary , Spry J. A. , Venkateswaran Kasthuri
Published: August 2009

A census of clean room surface-associated bacterial populations was derived from the results of both the cloning and sequencing of 16S rRNA genes and DNA microarray (PhyloChip) analyses. Samples from the Lockheed Martin Aeronautics Multiple Testing Facility (LMA-MTF), the Kennedy Space Center Payload Hazard and Servicing Facility (KSC-PHSF), and the Jet Propulsion Laboratory Spacecraft Assembly Facility (JPL-SAF) clean rooms were collected during the various assembly phases of the Phoenix and Mars Science Laboratory (MSL) spacecraft. Clone library-derived analyses detected a larger bacterial diversity prior to the arrival of spacecraft hardware in these clean room facilities. PhyloChip results were in agreement with this trend but also unveiled the presence of anywhere from 9- to 70-fold more bacterial taxa than cloning approaches. Among the facilities sampled, the JPL-SAF (MSL mission) housed a significantly less diverse bacterial population than either the LMA-MTF or KSC-PHSF (Phoenix mission). Bacterial taxa known to thrive in arid conditions were frequently detected in MSL-associated JPL-SAF samples, whereas proteobacterial lineages dominated Phoenix-associated KSC-PHSF samples. Comprehensive bacterial censuses, such as that reported here, will help space-faring nations preemptively identify contaminant biomatter that may compromise extraterrestrial life detection experiments. The robust nature and high sensitivity of DNA microarray technologies should prove beneficial to a wide range of scientific, electronic, homeland security, medical, and pharmaceutical applications and to any other ventures with a vested interest in monitoring and controlling contamination in exceptionally clean environments.
Comparative Transcriptomic Approach To Investigate Differences in Wine Yeast Physiology and Metabolism during Fermentation
Authors: Rossouw Debra , Olivares-Hernandes Roberto , Nielsen Jens , Bauer Florian F.
Published: August 2009

Commercial wine yeast strains of the speciesSaccharomyces cerevisiaehave been selected to satisfy many different, and sometimes highly specific, oenological requirements. As a consequence, more than 200 different strains with significantly diverging phenotypic traits are produced globally. This genetic resource has been rather neglected by the scientific community because industrial strains are less easily manipulated than the limited number of laboratory strains that have been successfully employed to investigate fundamental aspects of cellular biology. However, laboratory strains are unsuitable for the study of many phenotypes that are of significant scientific and industrial interest. Here, we investigate whether a comparative transcriptomics and phenomics approach, based on the analysis of five phenotypically diverging industrial wine yeast strains, can provide insights into the molecular networks that are responsible for the expression of such phenotypes. For this purpose, some oenologically relevant phenotypes, including resistance to various stresses, cell wall properties, and metabolite production of these strains were evaluated and aligned with transcriptomic data collected during alcoholic fermentation. The data reveal significant differences in gene regulation between the five strains. While the genetic complexity underlying the various successive stress responses in a dynamic system such as wine fermentation reveals the limits of the approach, many of the relevant differences in gene expression can be linked to specific phenotypic differences between the strains. This is, in particular, the case for many aspects of metabolic regulation. The comparative approach therefore opens new possibilities to investigate complex phenotypic traits on a molecular level.
Identification of Flagellar Motility Genes in
Yersinia ruckeri
by Transposon Mutagenesis
Authors: Evenhuis Jason P. , LaPatra Scott E. , Verner-Jeffreys David W. , Dalsgaard Inger , Welch Timothy J.
Published: August 2009

Here we demonstrate that flagellar secretion is required for production of secreted lipase activity in the fish pathogen
Yersinia ruckeri
and that neither of these activities is necessary for virulence in rainbow trout. Our results suggest a possible mechanism for the emergence of nonmotile biotype 2
Y. ruckeri
through the mutational loss of flagellar secretion.
Hyperglutamylation of Tubulin Can either Stabilize or Destabilize Microtubules in the Same Cell
Authors: Wloga Dorota , Dave Drashti , Meagley Jennifer , Rogowski Krzysztof , Jerka-Dziadosz Maria , Gaertig Jacek
Published: August 2009

In most eukaryotic cells, tubulin is subjected to posttranslational glutamylation, a conserved modification of unclear function. The glutamyl side chains form as branches of the primary sequence glutamic acids in two biochemically distinct steps: initiation and elongation. The length of the glutamyl side chain is spatially controlled and microtubule type specific. Here, we probe the significance of the glutamyl side chain length regulation in vivo by overexpressing a potent side chain elongase enzyme, Ttll6Ap, in
Tetrahymena
. Overexpression of Ttll6Ap caused hyperelongation of glutamyl side chains on the tubulin of axonemal, cortical, and cytoplasmic microtubules. Strikingly, in the same cell, hyperelongation of glutamyl side chains stabilized cytoplasmic microtubules and destabilized axonemal microtubules. Our observations suggest that the cellular outcomes of glutamylation are mediated by spatially restricted tubulin interactors of diverse nature.
Allosteric Regulation of Glucosamine-6-Phosphate Deaminase (NagB) and Growth ofEscherichia colion Glucosamine
Authors: Álvarez-Añorve Laura I. , Bustos-Jaimes Ismael , Calcagno Mario L. , Plumbridge Jacqueline
Published: August 2009

Growth onN-acetylglucosamine (GlcNAc) produces intracellularN-acetylglucosamine-6-phosphate (GlcNAc6P), which affects the regulation of the catabolism of amino sugars inEscherichia coliin two ways. First, GlcNAc6P is the inducing signal for the NagC repressor, and thus it increases the expression of the enzymes of thenagE-nagBACDoperon. Second, it is the allosteric activator of glucosamine-6P (GlcN6P) deaminase, NagB, and thus increases the catalytic capacity of this key enzyme in the metabolism of amino sugars. We showed previously that both the level of expression of thenagBgene and the transport of glucosamine were limiting the growth rate on GlcN (L. I. Álvarez-Añorve et al., J. Bacteriol. 187:2974-2982, 2005). We were unable to conclude if the lack of allosteric activation of wild-type NagB was also contributing to the slower growth rate on GlcN. Using a single-copy plasmid, with a constitutive promoter, we have separated the effects of GlcNAc6P on the NagB protein level and on deaminase activity. We show that over a range of intracellular NagB concentrations it is the quantity of the substrate, GlcN6P, which is limiting growth rather than the concentration of the allosteric activator, GlcNAc6P. On the other hand, the F174A mutant of NagB, which requires higher concentrations of GlcNAc6P for activity in vitro, grew better on GlcN in the presence of GlcNAc6P. However, wild-type NagB behaves as if it is already fully allosterically activated during growth on GlcN, and we present evidence suggesting that sufficient GlcNAc6P for allosteric activation is derived from the recycling of peptidoglycan.
Isocitrate Lyase Supplies Precursors for Hydrogen Cyanide Production in a Cystic Fibrosis Isolate of
Pseudomonas aeruginosa
Authors: Hagins Jessica M. , Locy Robert , Silo-Suh Laura
Published: August 2009

Pseudomonas aeruginosa
colonizes and can persist in the lungs of cystic fibrosis (CF) patients for decades. Adaptation of
P. aeruginosa
to the CF lung environment causes various genotypic and phenotypic alterations in the bacterium that facilitate persistence. We showed previously that isocitrate lyase (ICL) activity is constitutively upregulated in the
P. aeruginosa
CF isolate FRD1. We show here that high ICL activity in FRD1 contributes to increased hydrogen cyanide (HCN) production by this isolate. Disruption of
aceA
, which encodes ICL, results in reduced cyanide production by FRD1 but does not affect cyanide production in the wound isolate PAO1. Cyanide production is restored to the FRD1
aceA
mutant by addition of glyoxylate, a product of ICL activity, or glycine to the growth medium. Conversion of glyoxylate to glycine may provide a mechanism for increased cyanide production by
P. aeruginosa
growing on compounds that activate the glyoxylate pathway. Consistent with this hypothesis, disruption of PA5304, encoding a putative
d
-amino acid dehydrogenase (DadA), led to decreased cyanide production by FRD1. Cyanide production was restored to the FRD1
dadA
mutant by the addition of glycine, but not glyoxylate, to the growth medium, suggesting that loss of the ability to convert glyoxylate to glycine was associated with the
dadA
mutation. This was supported by increased glycine production from toluene-treated FRD1 cells with the addition of glyoxylate compared to FRD1
dadA
cells. This study indicates a larger role for ICL in the physiology and virulence of chronic isolates of
P. aeruginosa
than previously recognized.
Study of the EE mechanism with adsorption of the intermediate at spherical and planar electrodes following a Langmuir’s isotherm
Authors: Alcaraz María-Luisa , Gálvez Jesús
Published: August 2009

The theory for the EE mechanism with adsorption of the intermediate following Langmuir’s isotherm has been developed for the expanding sphere with any power law electrode model. The equations obtained with this model are general and can be applied, for example, to a stationary plane electrode, to a stationary sphere electrode, and to the two models of dropping mercury electrode (DME), expanding plane and expanding sphere. The influence exerted by the sphericity of the electrode on the current-potential (I/E) curves and the characteristics of these curves are discussed.
Data base for GC/MS identification of traces of organic impurities in atmospheric air
Authors: Ioffe Boris V. , Zenkevich Igor G. , Bureiko Andrei S.
Published: August 2009

A new approach to the GC/MS identification of organic components of the atmosphere is proposed. It is characterized by the use of averaged values of retention indices of different types at different temperatures in combination with several main peaks of mass spectra and allows considerable standard deviations of indices and peak intensities. Hence, it is possible to achieve good interlaboratory reproducibility of results working with simplest computers having a small operative memory. The data base contains averaged eight-peak mass spectra and retention indices on polymethylsiloxane stationary phases for about 600 volatile organic compounds constantly present in atmospheric air or those that should be checked in populated areas.
Synthesis of some new indolizino[2,3-g]quinoline-5,12-dione derivatives
Authors: Yanni Amal S.
Published: August 2009

Interaction of 6,7-dichloroquinoline-5,8-dione (I) with active methylene compounds and pyridine (or substituted pyridine) afforded indolizino[2,3-g]quinoline-5,12-diones (III, IV). When quinoline or isoquinoline was used instead of pyridine in the above reaction benzo[5,6]- or benzo[7,8]-indolizino[2,3-g]quinoline-5,12-diones (V, VI) were obtained. Their structure has been ascertained through elemental and spectral analysis.
Vapour-liquid equilibrium. The effect of temperature on the equilibrium vapour phase composition and on the azeotropic point composition
Authors: Novák Josef P. , Matouš Jaroslav , Voňka Petr
Published: August 2009

On the basis of analysis of calorimetric data, it is shown that the tert-butyl alcohol(1)-water(2) system exhibits the non-monotonous dependence of the equilibrium vapour phase composition on temperature which is reflected in the non-monotonous dependence of azeotropic composition on temperature. This behaviour is conditioned primarily by the fact that the molar heats of vaporization of both the substances have the same value at the temperature of 57°C. From the values of heats of vaporization of C3 and C4 alcohols and water it is evident that the analogous behaviour occurs also in aqueous systems of these alcohols at common temperatures.
Synthesis and biological activity of four vasopressin analogues substituted in position 2 by p-fluorophenylalanine
Authors: Lammek Bernard , Derdowska Izabela , Kupryszewski Gotfryd , Slaninová Jiřina , Barth Tomislav
Published: August 2009

Tyrosine in position 2 of AVP, dAVP, [Cpp1]AVP and [Cpp1, Val4]AVP was substituted by p-fluorophenylalanine and an effect of this change on agonistic/antagonistic activity in uterotonic, pressor or anti-antidiuretic test was followed. All the prepared analogues were found inhibitory in uterotonic test, however the inhibitory potency was rather low. As far as the pressor activity is concerned, the agonistic potency was slightly decreased (2-4 times), in comparison with the strong decrease of the inhibitory potency.
Comparison of binding affinities of a series of oxytocin analogues to uterine and mammary gland receptors and their biological potencies
Authors: Slaninová Jiřina , Hackenberg Mario , Fahrenholz Falk
Published: August 2009

The affinity of 12 oxytocin analogues of similar structure but differences in conformational freedom and agonistic and antagonistic properties to receptors in guinea pig uterus and rat mammary gland membrane preparations was determined by competitive binding experiments using tritiated oxytocin. The values obtained for the apparent dissociation constant KD were compared to the values of biological activities from classical pharmacological tests ( uterotonic test in vitro and galactogogic test in vivo).
The chemotherapy of psoriasis with azaribine: Mirage or miracle
Authors: Drell William , Škoda Jan , Welch Arnold D.
Published: August 2009

An antimetabolite, administered orally, which alleviates the symptoms and signs of severe psoriasis, azaribine (triacetyl-6-azauridine), was approved by the Food and Drug Administration (FDA of the USA) for clinical use in 1975, but 18 months later approval was withdrawn. The mechanism of action of azaribine (as a precursor of 6-azauridine 5’-azauridine 5’-monophosphate) is described and the probable cause of the infrequent vascular thromboses and a means of preventing them (by the co-administration of pyridoxine) are discussed.
An approach to the synthesis of novel 11-hydroxyartemisinin derivatives
Authors: Petrov Orlin , Ognyanov Iliya
Published: August 2009

The conversion of artemisinin (I) to the epoxide V and its use for the preparation of novel artemisinin derivatives as potential antimalarial drugs is described.
Unusual alkanes pattern of some plant cuticular waxes
Authors: Stránský Karel , Streibl Milan , Ubik Karel
Published: August 2009

Eight gas chromatograms present an unusual composition of alkanes ( including branched alkanes) from cuticular waxes. In plants of a lower phylogenetic class (liverwort, lichens), further in seeds and sprouts of tubers (Solanaceae) and especially in the anthers and pollens of some plants a high proportion of branched alkanes has been found (up to 72%).
Kinetics and mechanism of cyclization of N-(2-methoxycarbonylphenyl)-N’-methylsulphonamide to 3-methyl-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide
Authors: Kaválek Jaromír , Macháček Vladimír , Sedlák Miloš , Štěrba Vojeslav
Published: August 2009

The cyclization kinetics of N-(2-methylcarbonylphenyl)-N’-methylsulfonamide (IIb) into 3-methyl-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide (Ib) has been studied in ethanolamine, morpholine, and butylamine buffers and in potassium hydroxide solution. The cyclization is subject to general base and general acid catalysis. The value of the Bronsted coefficient β is about 0.1, which indicates that splitting off of the proton from negatively charged tetrahedral intermediate represents the rate-limiting and thermodynamically favourable step. In the solutions of potassium hydroxide the cyclization of dianion of the starting ester IIb probably becomes the rate-limiting step.
Syntheses of some cis mono-olefinic insect sex pheromones
Authors: Sharma Madan L. , Gupta Rashmi , Verma Sadhana
Published: August 2009

A convenient synthesis of cis mono-olefinic pheromone components I, II, and III has been achieved starting from (Z)-5-(2-tetrahydropyranyloxy)-pent-2-yn-1-ol (V) and (Z)-7-(2-tetrahydropyranyloxy)-hept-2-yn-1-ol (IV), both of which have been obtained from a common intermediate, viz. the dianion of prop-2-yn-1-ol.
Conductance and viscosity measurements of some electrolytes in binary solvent mixtures of dimethylsulphoxide and dioxane at 25 °C
Authors: Syal Vijay K. , Bisht Puspha , Ranowt Prakash C.
Published: August 2009

The conductance and viscosity measurements of Bu4NBPh4, Bu4NI, NaBPh4, Pr4NI, Et4NI, Me4NI, Bu4NNO3, KI, KClO4, NaClO4, KNO3, AgNO3, LiNO3 and NaBr have been carried out in the concentration range of (0-100) . 10-4 mol dm-3 for conductance and (0-250) . 10-4 mol dm-3 for viscosity in dimethylsulphoxide (DMSO) and DMSO + dioxane mixtures at 25°C. The conductance and viscosity data have been analysed by the Shedlovsky and Jones-Dole equations, respectively. The limiting ionic conductance (λi0), solvated radii (ri) and the ionic viscosity coefficient (B±) values have been evaluated. The variation of ri and B± value as a function of solvent composition has been interpreted in terms of preferential solvation of ions in these solvent mixtures.
Glassy carbon surface effects on the electroreduction of aromatic carbonyl compounds. II Benzophenone
Authors: Chandrasekaran Maruthai , Noel Michael , Krishnan Venkatasubramanian
Published: August 2009

Results of the voltammetric study of benzophenone reduction in dimethylformamide and aqueous media on GCE are presented together with the comparative discussion of the data for mercury and other electrodes available in the literature. The formation and stability of anion radicals and dianions and their reactivity with protonating agents on GCE are similar to those on mercury electrodes. A new surface prewave noticed in aprotic and neutral aqueous solutions on GCE has not so far been reported on any other electrode. All experimental evidences support the view that this prewave is due to the surface protonation by the acidic functional groups on GCE. The surface protonation is found to be a slow time-dependent process requiring 3-4 minutes for completion. The surface concentration evaluated from the faradaic response of the surface process is found to be around 30% or even less if the surface roughness factor is considered,. The importance of this finding to the general concept of surface acidity effects on electrocatalysis is also emphasised.
The Na+,K+/CN-,I- ternary reciprocal system
Authors: Drátovský Milan , Langová Ludmila , Makovička Jiří , Rosický Jaroslav
Published: August 2009

The DTA method was used to obtain the phase diagram of the Na+, K+/CN-, I- ternary reciprocal system. This system forms completely miscible solid solutions with two ternary minima with the parameters xNa+ = 0.50, xI- = 0.57, θ = 412°C, and xNa+ = 0.75, xI- = 0.20, θ = 428°C. The NaI-KCN diagonal is the stable diagonal.
Synthesis of the six isomeric thieno[c]-fused 1,5- and 1,6-naphthyridines
Authors: Gronowitz Salo , Malm Johan , Hörnfeldt Anna-Britta
Published: August 2009

trough the use of Pd(0)-catalyzed coupling between 2- and 4-formyl-3-thiopheneboronic acids and 3-amino-2-bromopyridine and 4-acetamido-3-bromopyridine, convenient one-pot procedures for the preparation of thieno[2,3-c]-1,5-naphthyridine, thieno[3,4-c]-1,5-naphthyridine, thieno-[2,3-c]-1,6-naphthyridine, and thieno[3,4-c]-1,6-naphthyridine have been developed. In order to obtain thieno[3,2-c]-1,6-naphthyridine 2-(tributylstannyl)-3-thiophene aldehyde had to be used, since the organometallic partner in the coupling reaction, 3-formyl-2-thipheneboronic acid, is too easily deboronated. The effect of silver(I) oxide and thallium(I) carbonate on the coupling was studied. 1H and 13C NMR spectra of the six isomeric thieno{c]-fused 1,5- and 1,6-naphthyridines are discussed.
5-Formylimidazo[2,1-b]thiazoles and derivatives with herbicidal activity
Authors: Andreani Aldo , Rambaldi Mirella , Locatelli Alessandra , Andreani Franco
Published: August 2009

A series of imidazo[2,1-b]thiazole derivatives including aldehydes (I-XXIX), oximes (XXX-XL) and 2,4-dinitrophenyloximes (XLI-LIII) were prepared and tested as potential herbicides. Many compounds were active in paddy field treatment, sand and in water culture. In upland condition, a number of dinitrophenyloximes proved herbicides in postemergence treatment, whereas in preemergence only compounds XVI, XXV and XLVIII showed some degree of activity.
The cytological diagnosis of paediatric renal tumours
Authors: Shet T , Viswanathan S
Published: August 2009

Fine needle aspiration cytology (FNAC) is used for preoperative diagnosis of paediatric renal tumours, especially in centres where preoperative chemotherapy is advocated in Wilms’ tumour. This review focuses on salient cytological features in specific paediatric renal tumours, the approach to resolving a differential diagnosis and the role of ancillary methods in diagnosis of paediatric renal tumours. Crucial differential diagnoses include distinguishing: Wilms’ tumour from benign tumours in the kidney like multicystic nephroma or congenital mesoblastic nephroma; aggressive non-Wilms’ tumours of kidney like rhabdoid tumour of kidney; and Wilms’ tumour from other paediatric round cell sarcomas like neuroblastoma, non-Hodgkin lymphoma etc. An approach based on classifying smears according to their cellular patterns as triphasic, round cell, spindle cell or epithelioid cell type assists in classifying paediatric renal tumours on cytology. Immunocytochemistry for WT1, cytokeratin, synaptophysin, leucocyte common antigen and MIC2 will aid in evaluating round cell tumours in the renal region, while WT1, bcl2, vimentin and desmin will be useful for spindle cell tumours in that region. Extra material can also be evaluated for demonstration of specific cytogenetic abnormalities in these tumours. A checklist of common tumours in a particular age group, relevant clinical information, awareness of distinctive and overlapping cytological features, and appropriate use of immunocytochemistry with cytogenetics go a long way in ensuring an accurate cytological diagnosis. Used judiciously, FNAC is as effective a tool as a core biopsy for preoperative diagnosis of paediatric renal tumours, and with experience a 92% accuracy rate can be achieved.