bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterisation and expression of secretory phospholipase A2group IB during ontogeny of Atlantic cod (Gadus morhua)
Authors: Sæle Øystein , Nordgreen Andreas , Olsvik Pål A. , Hamre Kristin
Published: September 2010

The pancreatic enzyme secretory phospholipase A2group IB (sPLA2IB) hydrolyses phospholipids at the sn-2 position, resulting in a NEFA and a lyso-phospholipid, which are then absorbed by the enterocytes. The sPLA2IB is a member of a family of nineteen enzymes sharing the same catalytic ability, of which nine are cytosolic and ten are secretory. Presently, there are no pharmacological tools to separate between the different secretory enzymes when measuring the enzymatic activity. Thus, it is important to support activity data with more precise techniques when isolation of intestinal content is not possible for analysis, as in the case of small teleost larvae, where the whole animal is sometimes analysed. In the present study, we characterise the sPLA2IB gene in Atlantic cod (Gadus morhua) and describe its ontogeny at the genetic and protein level and compare this to the total sPLA2activity level. A positive correlation was found between the expression of sPLA2IB mRNA and protein. Both remained stable and low during the larval stage followed by an increase from day 62 posthatch, coinciding with the development of the pyloric ceaca. Meanwhile, total sPLA2enzyme activity in cod was stable and relatively high during the early stages when larvae were fed live prey, followed by a decrease in activity when the fish were weaned to a formulated diet. Thus, the expression of sPLA2IB mRNA and protein did not correlate with total sPLA2activity.
Borderline personality disorder co-morbidity: relationship to the internalizing–externalizing structure of common mental disorders
Authors: Eaton N. R. , Krueger R. F. , Keyes K. M. , Skodol A. E. , Markon K. E. , Grant B. F. , Hasin D. S.
Published: September 2010

Background

Borderline personality disorder (BPD) shows high levels of co-morbidity with an array of psychiatric disorders. The meaning and causes of this co-morbidity are not fully understood. Our objective was to investigate and clarify the complex co-morbidity of BPD by integrating it into the structure of common mental disorders.

Method

We conducted exploratory and confirmatory factor analyses on diagnostic interview data from a representative US population-based sample of 34 653 civilian, non-institutionalized individuals aged ⩾18 years. We modeled the structure of lifetime DSM-IV diagnoses of BPD and antisocial personality disorder (ASPD), major depressive disorder, dysthymic disorder, panic disorder with agoraphobia, social phobia, specific phobia, generalized anxiety disorder, post-traumatic stress disorder, alcohol dependence, nicotine dependence, marijuana dependence, and any other drug dependence.

Results

In both women and men, the internalizing–externalizing structure of common mental disorders captured the co-morbidity among all disorders including BPD. Although BPD was unidimensional in terms of its symptoms, BPD as a disorder showed associations with both the distress subfactor of the internalizing dimension and the externalizing dimension.

Conclusions

The complex patterns of co-morbidity observed with BPD represent connections to other disorders at the level of latent internalizing and externalizing dimensions. BPD is meaningfully connected with liabilities shared with common mental disorders, and these liability dimensions provide a beneficial focus for understanding the co-morbidity, etiology and treatment of BPD.
Epigenetic and inflammatory marker profiles associated with depression in a community-based epidemiologic sample
Authors: Uddin M. , Koenen K. C. , Aiello A. E. , Wildman D. E. , de los Santos R. , Galea S.
Published: September 2010

Background

Recent work suggests that epigenetic differences may be associated with psychiatric disorders. Here we investigate, in a community-based sample, whether methylation profiles distinguish between individuals with and without lifetime depression. We also investigate the physiologic consequences that may be associated with these profiles.

Method

Using whole blood-derived genomic DNA from a subset of participants in the Detroit Neighborhood Health Study (DNHS), we applied methylation microarrays to assess genome-wide methylation profiles for over 14 000 genes in 33 persons who reported a lifetime history of depression and 67 non-depressed adults. Bioinformatic functional analyses were performed on the genes uniquely methylated and unmethylated in each group, and inflammatory biomarkers [interleukin (IL)-6 and C-reactive protein (CRP)] were measured to investigate the possible functional significance of the methylation profiles observed.

Results

Uniquely unmethylated gene sets distinguished between those withversuswithout lifetime depression. In particular, some processes (e.g. brain development, tryptophan metabolism) showed patterns suggestive of increased methylation among individuals with depression whereas others (e.g. lipoprotein) showed patterns suggestive of decreased methylation among individuals with depression. IL-6 and CRP levels were elevated among those with lifetime depression and, among those with depression only, IL-6 methylation showed an inverse correlation with circulating IL-6 and CRP.

Conclusions

Genome-wide methylation profiles distinguish individuals withversuswithout lifetime depression in a community-based setting, and show coordinated signals with pathophysiological mechanisms previously implicated in the etiology of this disorder. Examining epigenetic mechanisms in concert with other dynamic markers of physiologic functioning should improve our understanding of the neurobiology of depression.
A comprehensive review and model of putative prodromal features of bipolar affective disorder
Authors: Howes O. D. , Lim S. , Theologos G. , Yung A. R. , Goodwin G. M. , McGuire P.
Published: September 2010

Background

Identifying prodromal features that predate the onset of bipolar disorder (BD) may enable the prevention of BD and aid early intervention. This review addresses two key questions: Is there a bipolar prodrome? And, if there is, what are its characteristic features?

Method

A comprehensive search of databases (PubMed, Medline, EMBASE and PsycINFO) supplemented by hand searches was used to identify studies of symptoms preceding the onset of BD.

Results

Fifty-nine studies were identified, of which 14 met inclusion criteria. Symptoms can predate the onset of BD by months to years and can be categorized as attenuated forms of BD symptoms, general symptoms common to a range of mental disorders, and personality traits, particularly cyclothymia. Two studies provided sufficient data to enable sensitivity and specificity to be calculated. Specificity of several of the features was high (>90%) but sensitivity was generally low (all <60%). We propose a model based on the findings in the studies reviewed to illustrate the potential trajectory to BD and the points at which it may be possible to intervene.

Conclusions

Clinical features preceding the onset of BD can be identified. However, conclusions about whether there is a distinct prodrome to BD are restricted by the limitations of current evidence. The high specificity of some features suggests they may be useful in clinical practice. Large-scale longitudinal studies are needed to validate these features and characterize their specificity and sensitivity in independent samples.
Oil content and fatty acid composition variability in wild peanut species
Authors: Wang M. L. , Barkley N. A. , Chinnan M. , Stalker H. T. , Pittman R. N.
Published: September 2010

Wild peanut species are useful genetic resources for improving the levels of disease/pest resistance and for enhancing the quality of seed composition by interspecific hybridization. The variation in oil content and fatty acid composition of wild peanut species in the United States Department of Agriculture germplasm collection is unknown. Seeds available from 39 wild species (plus a cultivated peanut) were requested from the U.S. peanut germplasm collection. Oil content was measured using nuclear magnetic resonance, fatty acid composition was analysed using gas chromatography, and the D150N functional mutation of theFAD2Agene was screened by real-time PCR. Significant variability in oil content (41.7–61.3%) was identified among the wild peanut species.Arachis magnacontained significantly more oil (61%) than cultivated peanut (56%). There was no functional mutation identified within theFAD2Agene target, and no wild species were identified with a high ratio of oleic acid to linoleic acid. The results from gas chromatography and real-time PCR analyses were consistent. However,Arachis sylvestriscontained a significantly higher amount (22%) of long-chain fatty acid (LCFA) than the cultivated peanut (4%). Thus,A.magnaandA. sylvestrismay be good breeding materials to use for increasing oil content or LCFA composition of cultivated peanuts in breeding programs.
A first appraisal of prognostic ocean DMS models and prospects for their use in climate models
Authors: Le Clainche Yvonnick , Vézina Alain , Levasseur Maurice , Cropp Roger A. , Gunson Jim R. , Vallina Sergio M. , Vogt Meike , Lancelot Christiane , Allen J. Icarus , Archer Stephen D. , Bopp Laurent , Deal Clara , Elliott Scott , Jin Meibing , Malin Gill , Schoemann Véronique , Simó Rafel , Six Katharina D. , Stefels Jacqueline
Published: September 2010

Ocean dimethylsulfide (DMS) produced by marine biota is the largest natural source of atmospheric sulfur, playing a major role in the formation and evolution of aerosols, and consequently affecting climate. Several dynamic process‐based DMS models have been developed over the last decade, and work is progressing integrating them into climate models. Here we report on the first international comparison exercise of both 1D and 3D prognostic ocean DMS models. Four global 3D models were compared to global sea surface chlorophyll and DMS concentrations. Three local 1D models were compared to three different oceanic stations (BATS, DYFAMED, OSP) where available time series data offer seasonal coverage of chlorophyll and DMS variability. Two other 1D models were run at one site only. The major point of divergence among models, both within 3D and 1D models, relates to their ability to reproduce the summer peak in surface DMS concentrations usually observed at low to mid‐ latitudes. This significantly affects estimates of global DMS emissions predicted by the models. The inability of most models to capture this summer DMS maximum appears to be constrained by the basic structure of prognostic DMS models: dynamics of DMS and dimethylsulfoniopropionate (DMSP), the precursor of DMS, are slaved to the parent ecosystem models. Only the models which include environmental effects on DMS fluxes independently of ecological dynamics can reproduce this summer mismatch between chlorophyll and DMS. A major conclusion of this exercise is that prognostic DMS models need to give more weight to the direct impact of environmental forcing (e.g., irradiance) on DMS dynamics to decouple them from ecological processes.
Modeling canopy CO2 and H2O exchange of a temperate mixed forest
Authors: Shi Ting‐Ting , Guan De‐Xin , Wang An‐Zhi , Wu Jia‐Bing , Yuan Feng‐Hui , Jin Chang‐Jie , Zhang Mi
Published: September 2010

We tested a multilayered model that simulated half‐hour canopy CO2 and H2O exchange of a temperate forest mixed with broadleaved trees and Korean pine. The variables input to the model for scaling the fluxes from leaf to canopy included the vertical profiles of height, canopy thickness, and leaf biomass of the five dominant tree species. The diurnal and seasonal patterns of modeled CO2 and H2O fluxes agreed with measured values well during the nonstressed periods, while the model showed overestimation during the water‐stressed and high‐temperature periods, which appeared infrequently in our study site. We showed a strong correlation between 20‐layer daily modeled fluxes and eddy covariance measurements for CO2 (r2 = 0.734) and H2O (r2 = 0.785), during May to September 2003–2007. Different layered methods exerted influence on the radiation absorption within the canopy sublayers and hence on the CO2 and H2O flux outputs. CO2 and H2O fluxes based on the Gaussian 5‐layered method were 8% and 1% lower than those based on the 20‐layered method.
An assessment of the absolute accuracy of the Atmospheric Infrared Sounder v5 precipitable water vapor product at tropical, midlatitude, and arctic ground‐truth sites: September 2002 through August 2008
Authors: Bedka Sarah , Knuteson Robert , Revercomb Henry , Tobin David , Turner David
Published: September 2010

The Atmospheric Infrared Sounder (AIRS) is the first of a series of satellite sensors that exploit high spectral resolution and broad spectral coverage of the midinfrared to improve the retrieval accuracy of passive infrared sounding. The AIRS atmospheric retrieval goals are to obtain 1 K accuracy for 1 km layers below 100 mb for temperature and 10% for 2 km layers for water vapor in clear and most cloud conditions. The AIRS total column precipitable water vapor (PWV) is obtained by integrating the vertical profile of water vapor mixing ratio derived from cloud‐cleared radiances. The accuracy goal of the AIRS PWV product is 5%. This paper provides a validation of the AIRS PWV product at three distinct climate sites over the nearly full range of total water amounts observed on Earth (between 0.1 and 6.5 cm). Six years (September 2002 to August 2008) of AIRS v5 retrievals of PWV are evaluated against ground‐based microwave radiometer (MWR) data at three Department of Energy Atmospheric Radiation Measurement program (ARM) sites. The accuracy of the MWR PWV retrieval is estimated to be between 1% and 3%. This study shows that the agreement between the MWR and AIRS retrievals of PWV is within 5% at all three ARM climate sites for most conditions. The notable exceptions are (1) very dry cases (PWV < 1 cm) over the Southern Great Plains (SGP) land site during both daytime and nighttime, where AIRS is too moist by 15%–30% and (2) nighttime observations over the SGP land site for PWV > 1 cm, where AIRS is too dry by about 10%. The moist bias for low water amounts (usually observed during the winter) over land could be a surface emissivity–related error since very little bias is seen at the ARM Arctic site for similar water amounts. The cause of the dry bias at nighttime over land for moderate water amounts is not determined by this study. However, a spatial map of the diurnal bias in monthly AIRS water amount suggests that this effect is related to meteorological conditions in the U. S. Great Plains, which in the summertime is characterized by a moist boundary layer. The diurnal error in AIRS PWV at the SGP site seen with respect to the MWR data are confirmed by PWV amounts derived from a coincident ground‐based GPS receiver.
Isotopic composition of H2from wood burning: Dependency on combustion efficiency, moisture content, andδD of local precipitation
Authors: Röckmann Thomas , Gómez Álvarez Catalina X. , Walter Sylvia , van der Veen Carina , Wollny Adam G. , Gunthe Sachin S. , Helas Günther , Pöschl Ulrich , Keppler Frank , Greule Markus , Brand Willi A.
Published: September 2010

Differences in isotopic composition between the various sources of H2are large, but only a few measurements have been carried out to constrain them. Two conflicting values have been published for H2from biomass burning. Both rely on the assumption that the isotopic composition of H2should scale with the isotopic composition of the precipitation at the location where the biomass grew. Here we test this hypothesis using 18 wood samples collected from various locations around the globe. The sample locations cover a range ofδD content of H2in precipitation, from below −120‰ in Siberia and Canada to −15‰ in Zimbabwe. The results confirm the predicted dependence of the H2isotopic composition on the precipitation in the sampling region. The water content itself is found to at most slightly affect the results. Furthermore,δD of H2depends strongly on combustion efficiency. Thus, the isotopic composition of H2from biomass burning shows a strong variability around the globe and between different stages of a fire. It is suggested that, rather than a global bulk number, global models that attempt to reproduce the spatial and temporal distribution ofδD in H2should incorporate explicitly the variability ofδD(H2) from biomass burning onδD in precipitation.
A Bayesian approach for inverse modeling, data assimilation, and conditional simulation of spatial random fields
Authors: Rubin Yoram , Chen Xingyuan , Murakami Haruko , Hahn Melanie
Published: September 2010

This paper addresses the inverse problem in spatially variable fields such as hydraulic conductivity in groundwater aquifers or rainfall intensity in hydrology. Common to all these problems is the existence of a complex pattern of spatial variability of the target variables and observations, the multiple sources of data available for characterizing the fields, the complex relations between the observed and target variables and the multiple scales and frequencies of the observations. The method of anchored distributions (MAD) that we propose here is a general Bayesian method of inverse modeling of spatial random fields that addresses this complexity. The central elements of MAD are a modular classification of all relevant data and a new concept called “anchors.” Data types are classified by the way they relate to the target variable, as either local or nonlocal and as either direct or indirect. Anchors are devices for localization of data: they are used to convert nonlocal, indirect data into local distributions of the target variables. The target of the inversion is the derivation of the joint distribution of the anchors and structural parameters, conditional to all measurements, regardless of scale or frequency of measurement. The structural parameters describe large‐scale trends of the target variable fields, whereas the anchors capture local inhomogeneities. Following inversion, the joint distribution of anchors and structural parameters is used for generating random fields of the target variable(s) that are conditioned on the nonlocal, indirect data through their anchor representation. We demonstrate MAD through a detailed case study that assimilates point measurements of the conductivity with head measurements from natural gradient flow. The resulting statistical distributions of the parameters are non‐Gaussian. Similarly, the moments of the estimates of the hydraulic head are non‐Gaussian. We provide an extended discussion of MAD vis à vis other inversion methods, including maximum likelihood and maximum a posteriori with an emphasis on the differences between MAD and the pilot points method.
Experimental calcite dissolution under stress: Evolution of grain contact microstructure during pressure solution creep
Authors: Croizé Delphine , Renard François , Bjørlykke Knut , Dysthe Dag Kristian
Published: September 2010

For the first time, nanometer resolution techniques both in situ and ex situ were compared in order to study calcite dissolution under stress. The obtained results enabled identification of the relative importance of pressure solution driven by normal load and free surface dissolution driven by strain energy. It is found that pressure solution of calcite crystals at the grain scale occurred by two different mechanisms. Diffusion of the dissolved solid took place either at a rough calcite/indenter interface, or through cracks that propagated from the contact toward the less stressed part of the crystal. It is also found that strain rates are mostly a function of the active process, i.e., pressure solution associated or not with cracks, rather than being influenced by stress variations. Strain rates obtained in this study are in agreement with published data of experimental calcite and carbonate dissolution under stress.
A Web-Based Survey on Australian Community Pharmacists' Perceptions and Practices of Generic Substitution
Authors: Ping Chong Chee , March Geoff , Clark Alice , Gilbert Andrew , Hassali Mohamed Azmi , Bahari Mohd Baidi
Published: September 2010

This study evaluated Australian community pharmacists' perceptions and practices of generic substitution in response to recent changes in generic medicines policy under the Pharmaceutical Benefits Scheme reform. All community pharmacists in Australia were invited to participate in a web-based survey conducted in the year 2008 using a self-completed anonymous questionnaire. Useful responses were received from 157 community pharmacists. Of the respondents, 95.5 per cent indicated that their pharmacy had a policy that encouraged generic substitution. Most pharmacists (93.7 per cent) were willing to substitute generics for brand name medicines whenever permitted. Patient's acceptability and chronic diseases were the factors that significantly influenced the pharmacists to offer a generic substitute. Conversely, concern about patient confusion was the major barrier to generic substitution. Only 29.9 per cent of pharmacists firmly believed that substituting an originator brand with a generic would not have any effect on the therapeutic outcome. Around 13 per cent of respondents were somewhat concerned about side effects resulting from generic substitution. The majority of Australian pharmacists are highly supportive of generic substitution. There is need for an education programme to ensure pharmacists have a sound understanding of generic substitution before and following the implementation of any generic substitution policy by government.
Design of embedded chimeric peptide nucleic acids that efficiently enter and accurately reactivate gene expression in vivo
Authors: Chen Joy , Peterson Kenneth R. , Iancu-Rubin Camelia , Bieker James J.
Published: September 2010

Pharmacological treatments designed to reactivate fetal γ-globin can lead to an effective and successful clinical outcome in patients with hemoglobinopathies. However, new approaches remain highly desired because such treatments are not equally effective for all patients, and toxicity issues remain. We have taken a systematic approach to develop an embedded chimeric peptide nucleic acid (PNA) that effectively enters the cell and the nucleus, binds to its target site at the human fetal γ-globin promoter, and reactivates this transcript in adult transgenic mouse bone marrow and human primary peripheral blood cells. In vitro and in vivo DNA-binding assays in conjunction with live-cell imaging have been used to establish and optimize chimeric PNA design parameters that lead to successful gene activation. Our final molecule contains a specific γ-promoter-binding PNA sequence embedded within two amino acid motifs: one leads to efficient cell/nuclear entry, and the other generates transcriptional reactivation of the target. These embedded PNAs overcome previous limitations and are generally applicable to the design of in vivo transcriptional activation reagents that can be directed to any promoter region of interest and are of direct relevance to clinical applications that would benefit from such a need.
Essential role of the cAMP-cAMP response-element binding protein pathway in opiate-induced homeostatic adaptations of locus coeruleus neurons
Authors: Cao Jun-Li , Vialou Vincent F. , Lobo Mary Kay , Robison Alfred J. , Neve Rachael L. , Cooper Donald C. , Nestler Eric J. , Han Ming-Hu
Published: September 2010

Excessive inhibition of brain neurons in primary or slice cultures can induce homeostatic intrinsic plasticity, but the functional role and underlying molecular mechanisms of such plasticity are poorly understood. Here, we developed an ex vivo locus coeruleus (LC) slice culture system and successfully recapitulated the opiate-induced homeostatic adaptation in electrical activity of LC neurons seen in vivo. We investigated the mechanisms underlying this adaptation in LC slice cultures by use of viral-mediated gene transfer and genetic mutant mice. We found that short-term morphine treatment of slice cultures almost completely abolished the firing of LC neurons, whereas chronic morphine treatment increased LC neuronal excitability as revealed during withdrawal. This increased excitability was mediated by direct activation of opioid receptors and up-regulation of the cAMP pathway and accompanied by increased cAMP response-element binding protein (CREB) activity. Overexpression of a dominant negative CREB mutant blocked the increase in LC excitability induced by morphine- or cAMP-pathway activation. Knockdown of CREB in slice cultures from floxed CREB mice similarly decreased LC excitability. Furthermore, the ability of morphine or CREB overexpression to up-regulate LC firing was blocked by knockout of the CREB target adenylyl cyclase 8. Together, these findings provide direct evidence that prolonged exposure to morphine induces homeostatic plasticity intrinsic to LC neurons, involving up-regulation of the cAMP-CREB signaling pathway, which then enhances LC neuronal excitability.
Highly aneuploid zebrafish malignant peripheral nerve sheath tumors have genetic alterations similar to human cancers
Authors: Zhang GuangJun , Hoersch Sebastian , Amsterdam Adam , Whittaker Charles A. , Lees Jacqueline A. , Hopkins Nancy
Published: September 2010

Aneuploidy is a hallmark of human cancers, but most mouse cancer models lack the extensive aneuploidy seen in many human tumors. The zebrafish is becoming an increasingly popular model for studying cancer. Here we report that malignant peripheral nerve sheath tumors (MPNSTs) that arise in zebrafish as a result of mutations in either ribosomal protein (
rp
) genes or in
p53
are highly aneuploid. Karyotyping reveals that these tumors frequently harbor near-triploid numbers of chromosomes, and they vary in chromosome number from cell to cell within a single tumor. Using array comparative genomic hybridization, we found that, as in human cancers, certain fish chromosomes are preferentially overrepresented, whereas others are underrepresented in many MPNSTs. In addition, we obtained evidence for recurrent subchromosomal amplifications and deletions that may contain genes involved in cancer initiation or progression. These focal amplifications encompassed several genes whose amplification is observed in human tumors, including
met
,
cyclinD2
,
slc45a3
, and
cdk6
. One focal amplification included
fgf6a
. Increasing fgf signaling via a mutation that overexpresses
fgf8
accelerated the onset of MPNSTs in fish bearing a mutation in
p53
, suggesting that
fgf6a
itself may be a driver of MPNSTs. Our results suggest that the zebrafish is a useful model in which to study aneuploidy in human cancer and in which to identify candidate genes that may act as drivers in fish and potentially also in human tumors.
Branchiostoma floridae
has separate healing and sealing enzymes for 5′-phosphate RNA ligation
Authors: Englert Markus , Sheppard Kelly , Gundllapalli Sarath , Beier Hildburg , Söll Dieter
Published: September 2010

Animal cells have two tRNA splicing pathways: (
i
) a 5′-P ligation mechanism, where the 5′-phosphate of the 3′ tRNA half becomes the junction phosphate of the new phosphodiester linkage, and (
ii
) a 3′-P ligation process, in which the 3′-phosphate of the 5′ tRNA half turns into the junction phosphate. Although both activities are known to exist in animals, in almost three decades of investigation, neither of the two RNA ligases has been identified. Here we describe a gene from the chordate
Branchiostoma floridae
that encodes an RNA ligase (Bf RNL) with a strict requirement for RNA substrates with a 2′-phosphate terminus for the ligation of RNAs with 5′-phosphate and 3′-hydroxyl ends. Unlike the yeast and plant tRNA ligases involved in tRNA splicing, Bf RNL lacks healing activities and requires the action of a polynucleotide kinase (PNK) and a cyclic phosphodiesterase (CDPase)
in trans
. The activities of these two enzymes were identified in a single
B. floridae
protein (Bf PNK/CPDase). The combined activities of Bf RNL and Bf PNK/CPDase are sufficient for the joining of tRNA splicing intermediates in vitro, and for the functional complementation of a tRNA ligase-deficient
Saccharomyces cerevisiae
strain in vivo. Hence, these two proteins constitute the 5′-P RNA ligation pathway in an animal organism.
Variation in verbal fluency: A latent variable analysis of clustering, switching, and overall performance
Authors: Unsworth Nash , Spillers Gregory J. , Brewer Gene A.
Published: September 2010

Verbal fluency tasks have long been used to assess and estimate group and individual differences in executive functioning in both cognitive and neuropsychological research domains. Despite their ubiquity, however, the specific component processes important for success in these tasks have remained elusive. The current work sought to reveal these various components and their respective roles in determining performance in fluency tasks using latent variable analysis. Two types of verbal fluency (semantic and letter) were compared along with several cognitive constructs of interest (working memory capacity, inhibition, vocabulary size, and processing speed) in order to determine which constructs are necessary for performance in these tasks. The results are discussed within the context of a two-stage cyclical search process in which participants first search for higher order categories and then search for specific items within these categories.
IP3-dependent, post-tetanic calcium transients induced by electrostimulation of adult skeletal muscle fibers
Authors: Casas Mariana , Figueroa Reinaldo , Jorquera Gonzalo , Escobar Matías , Molgó Jordi , Jaimovich Enrique
Published: September 2010

Tetanic electrical stimulation induces two separate calcium signals in rat skeletal myotubes, a fast one, dependent on Cav 1.1 or dihydropyridine receptors (DHPRs) and ryanodine receptors and related to contraction, and a slow signal, dependent on DHPR and inositol trisphosphate receptors (IP3Rs) and related to transcriptional events. We searched for slow calcium signals in adult muscle fibers using isolated adult flexor digitorum brevis fibers from 5–7-wk-old mice, loaded with fluo-3. When stimulated with trains of 0.3-ms pulses at various frequencies, cells responded with a fast calcium signal associated with muscle contraction, followed by a slower signal similar to one previously described in cultured myotubes. Nifedipine inhibited the slow signal more effectively than the fast one, suggesting a role for DHPR in its onset. The IP3R inhibitors Xestospongin B or C (5 µM) also inhibited it. The amplitude of post-tetanic calcium transients depends on both tetanus frequency and duration, having a maximum at 10–20 Hz. At this stimulation frequency, an increase of the slow isoform of troponin I mRNA was detected, while the fast isoform of this gene was inhibited. All three IP3R isoforms were present in adult muscle. IP3R-1 was differentially expressed in different types of muscle fibers, being higher in a subset of fast-type fibers. Interestingly, isolated fibers from the slow soleus muscle did not reveal the slow calcium signal induced by electrical stimulus. These results support the idea that IP3R-dependent slow calcium signals may be characteristic of distinct types of muscle fibers and may participate in the activation of specific transcriptional programs of slow and fast phenotype.
Coordinated control of sensitivity by two splice variants of Gαo in retinal ON bipolar cells
Authors: Okawa Haruhisa , Pahlberg Johan , Rieke Fred , Birnbaumer Lutz , Sampath Alapakkam P.
Published: September 2010

The high sensitivity of scotopic vision depends on the efficient retinal processing of single photon responses generated by individual rod photoreceptors. At the first synapse in the mammalian retina, rod outputs are pooled by a rod “ON” bipolar cell, which uses a G-protein signaling cascade to enhance the fidelity of the single photon response under conditions where few rods absorb light. Here we show in mouse rod bipolar cells that both splice variants of the Go α subunit, Gαo1 and Gαo2, mediate light responses under the control of mGluR6 receptors, and their coordinated action is critical for maximizing sensitivity. We found that the light response of rod bipolar cells was primarily mediated by Gαo1, but the loss of Gαo2 caused a reduction in the light sensitivity. This reduced sensitivity was not attributable to the reduction in the total number of Go α subunits, or the altered balance of expression levels between the two splice variants. These results indicate that Gαo1 and Gαo2 both mediate a depolarizing light response in rod bipolar cells without occluding each other’s actions, suggesting they might act independently on a common effector. Thus, Gαo2 plays a role in improving the sensitivity of rod bipolar cells through its action with Gαo1. The coordinated action of two splice variants of a single Gα may represent a novel mechanism for the fine control of G-protein activity.
Dynamics of Soybean Rust Epidemics in Sequential Plantings of Soybean Cultivars in Nigeria
Authors: Twizeyimana M. , Ojiambo P. S. , Hartman G. L. , Bandyopadhyay R.
Published: September 2010

Soybean rust, caused by Phakopsora pachyrhizi, is an important foliar disease of soybean. Disease severity is dependent on several environmental factors, although the precise nature of most of these factors under field conditions is not known. To help understand the environmental factors that affect disease development, soybean rust epidemics were studied in Nigeria by sequentially planting an early-maturing, highly susceptible cultivar, TGx 1485-1D, and a late-maturing, moderately susceptible cultivar, TGx 1448-2E, at 30- to 45-day intervals from August 2004 to September 2006. Within each planting date, disease onset occurred earlier on TGx 1485-1D than on TGx 1448-2E, and rust onset was at least 20 days earlier on soybean planted between August and October than on soybean planted between November and April. The logistic model provided a better description of the temporal increase in rust severity than the Gompertz model. Based on the logistic model, the highest absolute rates of disease increase were observed on soybean planted in September 2006 and October 2004 for TGx 1485-1D and TGx 1448-2E, respectively. Disease severity as measured by the relative area under disease progress curve (RAUDPC) was significantly (P < 0.05) negatively correlated with evaporation (r = –0.73), solar radiation (r = –0.59), and temperature (r = –0.64) but positively correlated with urediniospore concentration (r = 0.58). Planting date and soybean cultivar significantly (P < 0.05) affected disease severity, with severity being higher on soybean crops planted during the wet season than those planted in the dry season. Within the wet season, planting in May and July resulted in a significantly (P < 0.05) lower RAUDPC than planting between August and October. Yields were significantly (P < 0.001) related to RAUDPC during the wet season, whereby an increase in RAUDPC resulted in a linear decrease in yield. This study suggests that selection of planting date could be a useful cultural practice for reducing soybean rust.
First Report of Botryosphaeria dothidea Causing Shoot Blight of Kiwifruit (Actinidia deliciosa) in Greece
Authors: Thomidis T. , Exadaktylou E.
Published: September 2010

In the spring of 2010, in commercial orchards located in the Prefecture of Pieria in northern Greece, wilted shoots of kiwifruit cv. Hayward were observed. Blighted shoots took on a distinct dark color. Isolations from the lower margins of the cankers were made by plating sodium-hypochlorite-treated shoot tissue sections of approximately 3 mm on acidified (2.5 ml of 85% lactic acid per liter of nutrient medium to create a pH = 3.5 after autoclaving) potato dextrose agar. Plates were incubated at 23°C for 5 days, and a fast-growing, mouse-gray colored fungus was consistently isolated from diseased stems. Identification of the pathogen was based on morphological characteristics and confirmed by using the four random amplified polymorphic DNA primers (K19 [CAC AGG CGG A], K20 [GTG TCG CGA G], R13 [GGA CGA CAA G], and R15 [GGA CAA CGA G], suggested by Ma et al. (2). This fungus formed darkly pigmented pycnidia (170 × 155 μm), while the conidia observed in these bodies were one-celled, hyaline, ellipsoidal to fusoid with distinctly truncate bases, and measured 10.9 to 21.55 × 3.25 to 10.10 μm. The pycnidia exuded conidia in white tendrils. Koch's postulates were completed in the laboratory by inoculating 20 segments (6 cm long and 1.5 to 2 cm in diameter) of 1-year-old woody shoots of kiwifruit cv. Hayward. Using a cork borer, a 7-mm-diameter wound was created in the middle of each shoot segment by removing the bark and a 6-mm-diameter agar plug bearing mycelia from a 15-day-old culture of B. dothidea was inserted into the wound. The wound was covered with petroleum jelly and wrapped with adhesive tape to prevent desiccation. Ten control segments were similarly wounded and inoculated with an agar disk without fungal mycelium. All inoculated and noninoculated shoot segments were incubated at 25°C in moist chambers, after which the resulting necrosis was recorded. Koch's postulates were satisfied after reisolating the fungus from inoculated shoots that developed symptoms similar to those observed on shoots collected from orchards. Although B. dothidea has been previously reported to cause dieback on kiwifruit in Japan (1), to our knowledge, this is the first report of the occurrence of B. dothidea on kiwifruit in Greece. This pathogen can cause a high level of shoot blights in diseased plants and presents a significant threat to the commercial kiwifruit production in Greece.

References: (1) M. Kinugawa and T. Sato. Ann. Phytopathol. Soc. Jpn. 69:373, 2003. (2) Z. Ma et al. Phytopathology 91:665, 2001.
First Report of an Armillaria Root Disease Pathogen, Armillaria gallica, Associated with Several New Hosts in Hawaii
Authors: Kim M.-S. , Hanna J. W. , Klopfenstein N. B.
Published: September 2010

The loss and decline of native tree species caused by invasive plant pathogens is a major threat to the endangered endemic forests of the Hawaiian Islands (3). Thus, it is critical to characterize existing pathogens to evaluate potential invasiveness. In August 2005, rhizomorphs and mycelial bark fans of genet HI-4 were collected from dead/declining, mature trees of introduced Monterey pine (Pinus radiata) on the southern flank of Mauna Kea, Hawaii (approximately 19°42′55″N, 155°26′48″W, elevation 2,175 m). In March of 2008, three additional genets (HI-11, HI-13, and HI-16) were collected as rhizomorphs at a site named Pu'u La'au (west slope of the Mauna Kea Forest Reserve area, approximately 19°50′00″N, 155°35′35″W, elevation 2,275 to 2,550 m), approximately 20 km west-northwest of the HI-4 collection. These genets were collected from apparently healthy loblolly pine (Pinus taeda) that were introduced, apparently healthy māmane (Sophora chrysophylla; an endemic tree species of Hawaii), dead and dying māmane, and apparently healthy Methley plum (Prunus cerasifera × Prunus salicina) that was planted. All isolates were determined to have identical sequences in the intergenic spacer-1 rDNA region (GenBank Accession No. DQ995357). On the basis of somatic paring tests against North American Armillaria tester strains and 99% nucleotide sequence identities to GenBank Accession Nos. AY190245 and AY190246, these isolates were identified as Armillaria gallica. Past surveys have noted A. mellea sensu lato and A. nabsnona on numerous hosts in Hawaii, including māmane (3,4). However, to our knowledge, this is the first confirmed report of A. gallica in Hawaii, where it was found on māmane, Monterey pine, loblolly pine, and Methley plum. A. gallica has been widely categorized as a beneficial saprophyte, an opportunistic pathogen, or an aggressive pathogen (2). A recent study suggests that A. gallica can be highly pathogenic in some areas of the eastern United States and it is an important component of forest decline (2), especially under increasing stressors such as climate change. The isolation of A. gallica from declining stands on both introduced and endemic hosts under drought conditions suggests this pathogen is a contributing factor to forest decline on the island of Hawaii. Because the māmane tree is an important component of the native forest stands and essential to the endangered palila bird (Loxioides bailleui), which feeds almost exclusively on its green seeds (1), continued monitoring of Armillaria root disease is warranted.

References: (1) P. C. Banko et al. J. Chem. Ecol. 28:1393, 2002. (2) N. J. Brazee and R. L. Wick. For. Ecol. Manage. 258:1605, 2009. (3) R. E. Burgan and R. E. Nelson. USDA For. Serv. Tech. Rep. PSW-3, 1972. (4) J. W. Hanna et al. Plant Dis. 91:634, 2007.
Host Range, Biological Variation, and Phylogenetic Diversity ofEutypa latain California
Authors: Trouillas F. P. , Gubler W. D.
Published: September 2010

The objectives of this study were to investigate the host range of Eutypa lata in the major grape-growing regions in California and to analyze the phenotypic variation and phylogenetic diversity of E. lata isolates. Perithecia of E. lata were found on grapevines, in apricot, almond, cherry, apple, and pear tree orchards, and on ornamentals (oleander) and native plant species (California buckeye, big leaf maple, and willow). Multigene phylogenies of ribosomal DNA internal transcribed spacer, β-tubulin, and RPB2 genes confirmed the identity of E. lata recovered from the various host plants but also revealed sequence differences among isolates. The intraspecific phylogenetic diversity of E. lata did not correspond to geography or source of isolation, and intraspecific groups were not consistent across the different DNA phylogenies. Significant phenotypic variation also was detected among E. lata isolates, including ascospore and conidium length as well as level of aggressiveness on grapevines. Pathogenicity studies proved that all isolates were infectious to grapevine, suggesting that the native vegetation surrounding vineyards can serve as inoculum sources that may constitute an important element in the epidemiology of Eutypa dieback in grapevines.
Disease-Reducing Effect of Chromolaena odorata Extract on Sheath Blight and Other Rice Diseases
Authors: Khoa Nguyễn Đắc , Thúy Phan Thị Hồng , Thủy Trần Thị Thu , Collinge David B. , Jørgensen Hans Jørgen Lyngs
Published: September 2010

Sheath blight caused by Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is a major cause of crop loss in intensive rice production systems. No economically viable control methods have been developed. We screened aqueous extracts of common herbal plants that could reduce sheath blight lesions and found that foliar spraying and seed soaking application of extracts of either fresh or dried leaves of Chromolaena odorata gave up to 68% reduction in sheath blight lesion lengths under controlled and semi-field conditions. The observed reductions were not dependent on growth conditions of C. odorata and rice cultivar. The effect was observed until 21 days after inoculation and was not dependent on microbial activity. Under semi-field conditions, extracts also reduced severity of other important rice diseases, i.e., blast (Pyricularia oryzae) using foliar spray (up to 45%), brown spot (Bipolaris oryzae) using seed treatment (up to 57%), and bacterial blight (Xanthomonas oryzae pv. oryzae) using both application methods (up to 50%).
Mrt, a Gene Unique to Fungi, Encodes an Oligosaccharide Transporter and Facilitates Rhizosphere Competency in Metarhizium robertsii
Authors: Fang Weiguo , St. Leger Raymond J.
Published: September 2010

The symbiotic associations between rhizospheric fungi and plants have enormous environmental impact. Fungi are crucial to plant health as antagonists of pathogens and herbivores and facilitate the uptake of soil nutrients. However, little is known about the plant products obtained by fungi in exchange or how they are transported through the symbiotic interface. Here, we demonstrate that sucrose and raffinose family oligosaccharides in root exudates are important for rhizosphere competence in the insect pathogen Metarhizium robertsii (formerly known as Metarhizium anisopliae). We identified mutants in the Metarhiziumraffinose transporter (Mrt) gene of M. robertsii that grew poorly in root exudate and were greatly reduced in rhizosphere competence on grass roots. Studies on sugar uptake, including competition assays, revealed that MRT was a sucrose and galactoside transporter. Disrupting MRT resulted in greatly reduced or no growth on sucrose and galactosides but did not affect growth on monosaccharides or oligosaccharides composed entirely of glucose subunits. Consistent with this, expression of Mrt is exclusively up-regulated by galactosides and sucrose. Expressing a green fluorescent protein gene under the control of the Mrt promoter confirmed that MRT was expressed by germlings in the vicinity of grass roots but not in surrounding bulk soil. Disrupting Mrt did not reduce virulence to insects, demonstrating that Mrt is exclusively involved in M. robertsii’s interactions with plants. To our knowledge, MRT is the first oligosaccharide transporter identified and characterized in a fungus and is unique to filamentous fungi, but homologous genes in Magnaporthe, Ustilago, Aspergillus, Fusarium, Epichloe, and Penicillium species indicate that oligosaccharide transport is of widespread significance.
Competitive Strategy and Performance of Exporting SMEs: An Empirical Investigation of the Impact of Their Export Information Search and Competencies
Authors: Julien Pierre-André , Ramangalahy Charles
Published: September 2010

The SMEs‘ limited capacity to acquire information and use sources is a major factor explaining their low level of involvement and performance on export markets. Nonetheless, a small amount of applied research has been undertaken on this subject. We present the results of an inquiry into the impact of information search and competencies on the competitive strategy and export performance of 346 exporting manufacturing SMEs. The research model postulates that the performance of these SMEs is determined by their general competitive strategy, which in turn is explained by the ability of the business to acquire and manage foreign market information. The results of an analysis using a PLS method confirm three of the four hypotheses.
IPO Underpricing: A Meta-Analysis and Research Synthesis
Authors: Daily Catherine M. , Trevis Certo S. , Dalton Dan R. , Roengpitya Rungpen
Published: September 2010

Initial public offerings (IPOs) have been a prominent focus of academic and popular press attention, especially in recent years. Much of this attention can be attributed to the increase in IPO activity as a function of the “dot com” phenomenon. Of particular interest to both academics and practitioners is IPO underpricing. Review of existing research suggests little consensus regarding those factors associated with underpricing. We provide a meta-analysis of published studies. Our findings reveal a number of significant relationships, many of which are opposite that predicted by signaling theory. Implications of these findings for practice and future research are discussed.