bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biodiversity and distribution of epibiontic communities on Caridina ensifera (Crustacea, Decapoda, Atyidae) from Lake Poso: comparison with another ancient lake system of Sulawesi (Indonesia)
Authors: Fernandez‐Leborans Gregorio , Von Rintelen Kristina 
Published: February 2009

AbstractFernandez‐Leborans, G. and von Rintelen, K. 2010. Biodiversity and distribution of epibiontic communities on Caridina ensifera (Crustacea, Decapoda, Atyidae) from Lake Poso: comparison with another ancient lake system of Sulawesi (Indonesia). — Acta Zoologica (Stockholm) 91: 163–175The epibiont communities of the shrimp Caridina ensifera, endemic to Lake Poso (Sulawesi, Indonesia), were analysed. Most of the epibiont species were ciliated protozoa belonging to three suctorian genera (Acineta, Podophrya and Spelaeophrya), three peritrich genera (Zoothamnium, Vorticella and Cothurnia), and a haptorid genus (Amphileptus). There was also a rotifer epibiont of the genus Embata. Epibionts were identified to species level. There were 14 to 1114 epibionts per shrimp. The distribution of the epibiont species on the surface of the basibiont was recorded, calculating the number on the different colonized individuals of C. ensifera. The most abundant species, Zoothamnium intermedium and Acineta sulawesiensis, were also the most widely distributed. There was a significant difference between the spatial distributions of the different epibiont species. The analysis of the number of the epibiont species throughout the anteroposterior axis of the shrimp showed a gradient from the anterior to the posterior end of the body. Data from Lake Poso were compared with those of the Malili lake system (Sulawesi), obtained from its endemic shrimp, Caridina lanceolata. Lake Poso had the highest mean diversity, while Lake Mahalona showed the highest maximum diversity. All lakes were correlated with respect to the mean number of epibionts on the anatomical units of the shrimp, which showed a similar general distribution. The distributions of the different epibiont species were compared between the lakes. The possible adaptations of the epibionts as well as the colonization patterns were discussed. From the statistical results and the analysis of the distributions, we propose that in these communities epibiont species have a pattern of colonization in which they follow a behaviour as a whole; each species has a differential distribution, with the species occupying the available substratum with the particular requirements of each functional group, but there is a trend towards maintaining an equilibrium among species and groups, compensating for diversity and number of individuals. In all lakes there was an epibiont distribution model comprising the maintenance of an anteroposterior axis gradient, which was supported by the fluctuation in diversity and number of individuals of the different functional groups of epibiont species. The functional role of the different groups of species seems to tend towards sustainability with little global variation among the lakes.
Organizational Ambidexterity: Towards a Multilevel Understanding
Authors: Simsek Zeki 
Published: February 2009

abstractAlthough interest in the concept of organizational ambidexterity has increased during recent years, this line of inquiry remains unfocused and limited due to a lack of more encompassing conceptual efforts. As a first step, we begin by critically reviewing previous research on the conceptualization, antecedents, and consequences of ambidexterity. We then offer a model that specifies a more encompassing, multilevel explanation of ambidexterity. Finally, we trace research and managerial implications and suggest some potential research avenues.
Atypical brain responses to sounds in children with specific language and reading impairments
Authors: McArthur Genevieve , Atkinson Carmen , Ellis Danielle 
Published: February 2009

Abstract This study tested if children with specific language impairment (SLI) or children with specific reading disability (SRD) have abnormal brain responses to sounds. We tested 6‐ to 12‐year‐old children with SLI (N =19), children with SRD (N =55), and age‐matched controls (N =36) for their passive auditory event‐related potentials (ERPs) to tones, rapid tones, vowels and consonant‐vowels. Thirty‐eight percent of the children with SLI or SRD had less typical passive auditory ERPs in the N1–P2 window to sounds in general, rather than to tones, rapid tones, vowels or consonant‐vowels specifically. The ERPs of these children were significantly ‘flatter’ in the N1–P2 region than normal. All the children with flatter ERPs in the N1–P2 region had poor non‐word reading. A subgroup of these poor non‐word readers also had poor non‐word repetition. These findings support the hypothesis that impaired auditory processing is a causal risk factor for both SLI and SRD.
Differences in the neural mechanisms of selective attention in children from different socioeconomic backgrounds: an event‐related brain potential study
Authors: Stevens Courtney , Lauinger Brittni , Neville Helen 
Published: February 2009

Abstract Previous research indicates that children from lower socioeconomic backgrounds show deficits in aspects of attention, including a reduced ability to filter irrelevant information and to suppress prepotent responses. However, less is known about the neural mechanisms of group differences in attention, which could reveal the stages of processing at which attention deficits arise. The present study examined this question using an event‐related brain potential (ERP) measure of selective auditory attention. Thirty‐two children aged from 3 to 8 years participated in the study. Children were cued to attend selectively to one of two simultaneously presented narrative stories. The stories differed in location (left/right speaker), narration voice (male/female), and content. ERPs were recorded to linguistic and non‐linguistic probe stimuli embedded in the attended and unattended stories. Children whose mothers had lower levels of educational attainment (no college experience) showed reduced effects of selective attention on neural processing relative to children whose mothers had higher levels of educational attainment (at least some college). These differences occurred by 100 milliseconds after probe onset. Furthermore, the differences were related specifically to a reduced ability to filter irrelevant information (i.e. to suppress the response to sounds in the unattended channel) among children whose mothers had lower levels of education. These data provide direct evidence for differences in the earliest stages of processing within neural systems mediating selective attention in children from different socioeconomic backgrounds. Results are discussed in the context of intervention programs aimed at improving attention and self‐regulation abilities in children at‐risk for school failure.
The shift in infant preferences for vowel duration and pitch contour between 6 and 10 months of age
Authors: Kitamura Christine , Notley Anna 
Published: February 2009

Abstract This study investigates the influence of the acoustic properties of vowels on 6‐ and 10‐month‐old infants’ speech preferences. The shape of the contour (bell or monotonic) and the duration (normal or stretched) of vowels were manipulated in words containing the vowels /i/ and /u/, and presented to infants using a two‐choice preference procedure. Experiment 1 examined contour shape: infants heard either normal‐duration bell‐shaped and monotonic contours, or the same two contours with stretched duration. The results show that 6‐month‐olds preferred bell to monotonic contours, whereas 10‐month‐olds preferred monotonic to bell contours. In Experiment 2, infants heard either normal‐duration and stretched bell contours, or normal‐duration and stretched monotonic contours. As in Experiment 1, infants showed age‐specific preferences, with 6‐month‐olds preferring stretched vowels, and 10‐month‐olds preferring normal‐duration vowels. Infants’ attention to the acoustic qualities of vowels, and to speech in general, undergoes a dramatic transformation in the final months of the first year, a transformation that aligns with the emergence of other developmental milestones in speech perception.
‘New Governance’ in European Corporate Law Regulation as Transnational Legal Pluralism
Authors: Zumbansen Peer 
Published: February 2009

AbstractThe present transformation of European corporate governance regulation mirrors the challenges that have been facing the EU's continuously evolving polity, marked by tensions between centralised integration programmes, on the one hand, and Member State's embedded capitalisms, path‐dependencies and rent‐seeking, on the other. As longstanding concerns with remaining obstacles to more mobility for workers, services, business entities and capital in recent years are aligned with post‐Lisbon commitments to creating the world's leading competitive market, European corporate governance regulation (ECGR) has become exposed to and implicated in a set of highly dynamic regulatory experiments. In this context, ‘New Governance’ offers itself as both a tentative label and immodest proposal for a more responsive and innovative approach to European law making. The following article assesses the recently emerging regulatory forms in ECGR as illustrations of far‐reaching transformations in market governance. The arguable parallels between the EU's regulatory transformation in response to growing legitimacy concerns and the recurring question about whose interests a business corporation is intended to serve, provide the framework for an exploration of current regulatory trajectories in European corporate law that can most adequately be understood as a telling example of transnational legal pluralism.
Genetic influences on heart rate variability at rest and during stress
Authors: Wang Xiaoling , Ding Xiuhua , Su Shaoyong , Li Zhibin , Riese Harriette , Thayer Julian F. , Treiber Frank , Snieder Harold 
Published: February 2009

AbstractWe tested whether the heritability of heart rate variability (HRV) under stress is different from rest and its dependency on ethnicity or gender. HRV indexed by root mean square of successive differences (RMSSD) and high‐frequency (HF) power was measured at rest and during 3 stressors in 427 European and 308 African American twins. No ethnic or gender differences were found for any measures. There was a nonsignificant increase in heritability of RMSSD (from 0.48 to 0.58) and HF (from 0.50 to 0.58) under stress. Up to 81% and 60% of the heritabilities of RMSSD and HF under stress could be attributed to genes influencing rest levels. The heritabilities due to genes expressed under stress were 0.11 for RMSSD and 0.23 for HF. The findings suggest that, independent of ethnicity and gender, HRV regulation at rest and under stress is largely influenced by the same genes with a small but significant contribution of stress‐specific genetic effects.
Postauricular reflex responses to pictures varying in valence and arousal
Authors: Gable Philip A. , Harmon‐Jones Eddie 
Published: February 2009

AbstractReflexes are modulated by emotions. Much research has revealed that the startle reflexive eyeblink response is modulated by emotion, particularly in response to pictures of emotional scenes. Investigations of other reflexes are limited. Recently, research suggested that the postauricular reflex in response to a startling noise was modulated by emotion. In particular, pleasant stimuli enhanced the postauricular reflex. However, these first investigations were limited: One experiment demonstrated only a marginal difference between the pleasant stimuli and neutral stimuli and the other lacked the typical neutral scene comparison. The present experiment was designed to assess whether significant emotion versus neutral differences would occur. Results demonstrated that pleasant stimuli, regardless of arousal level, evoked larger postauricular reflex activation than neutral and unpleasant emotional stimuli.
Concordant up‐regulation of cytochrome P450 Cyp3a11, testosterone oxidation and androgen receptor expression in mouse brain after xenobiotic treatment
Authors: Meyer Ralf Peter , Gehlhaus Marcel , Schwab Ricarda , Bürck Carolin , Knoth Rolf , Hagemeyer Christoph Eugen 
Published: February 2009

AbstractInactivation of testosterone by specific hydroxylations is a main function of cytochrome P450 (P450, CYP) in the brain. Recent data imply that induction of brain P450s by neuroactive drugs alters steroid hormone levels and endocrine signalling, giving rise to endocrine disorders. In this study, we investigated this drug–hormone crosstalk in mouse brain. Phenytoin led to a significant increase of 2α‐, 2β‐, 6β‐, 16α‐ and 16β‐hydroxytestosterones, while 6α‐ and 15α‐hydroxytestosterones showed no significant alteration of their metabolism compared with untreated controls. Inhibition of testosterone hydroxylation using the chemical inhibitors orphenadrine, chloramphenicol, ketoconazole and nifedipine as well as antibodies against CYP3A‐ and 2B‐isoforms pointed to major role of Cyp3a11 and an only minor function of Cyp2b9/10 in mouse brain. Cyp3a11 revealed to be the major isoform affected by phenytoin. There was considerable overlap of Cyp3a11 and AR expression in neuronal structures of the limbic system, namely the hippocampus, amygdala, hypothalamus and thalamus. Phenytoin treatment led to an increase of both, Cyp3a11 and AR expression in the limbic system. Additionally, the coherence between CYP3A and AR expression was analysed in PC‐12 cells. Inhibition of phenytoin‐induced endogenous CYP3A2 and AR by ketoconazole led a reduction of their expression to basal levels. We conclude that Cyp3a11 plays a crucial role in directing drug action to hormonal response within the limbic system of mouse brain in a so‐called drug–hormone crosstalk.
Simultaneous single neuron recording of O2 consumption, [Ca2+]i and mitochondrial membrane potential in glutamate toxicity
Authors: Gleichmann Marc , Collis Leon P. , Smith Peter J. S. , Mattson Mark P. 
Published: February 2009

AbstractIn order to determine the sequence of cellular processes in glutamate toxicity, we simultaneously recorded O2 consumption, cytosolic Ca2+ concentration ([Ca2+]i), and mitochondrial membrane potential (mΔψ) in single cortical neurons. Oxygen consumption was measured using an amperometric self‐referencing platinum electrode adjacent to neurons in which [Ca2+]i and mΔψ were monitored with Fluo‐4 and TMRE+, respectively, using a spinning disk laser confocal microscope. Excitotoxic doses of glutamate caused an elevation of [Ca2+]i followed seconds afterwards by an increase in O2 consumption which reached a maximum level within 1–5 min. A modest increase in mΔψ occurred during this time period, and then, shortly before maximal O2 consumption was reached, the mΔψ, as indicated by TMRE+ fluorescence, dissipated. Maximal O2 consumption lasted up to 5 min and then declined together with mΔψ and ATP levels, while [Ca2+]i further increased. mΔψ and [Ca2+]i returned to baseline levels when neurons were treated with an NMDA receptor antagonist shortly after the [Ca2+]i increased. Our unprecedented spatial and time resolution revealed that this sequence of events is identical in all neurons, albeit with considerable variability in magnitude and kinetics of changes in O2 consumption, [Ca2+]i, and mΔψ. The data obtained using this new method are consistent with a model where Ca2+ influx causes ATP depletion, despite maximal mitochondrial respiration, minutes after glutamate receptor activation.
Glutamate‐induced post‐activation inhibition of locus coeruleus neurons is mediated by AMPA/kainate receptors and sodium‐dependent potassium currents
Authors: Zamalloa Teresa , Bailey Christopher P. , Pineda Joseba 
Published: February 2009

Background and purpose:  Locus coeruleus (LC) neurons respond to sensory stimuli with a glutamate‐triggered burst of spikes followed by an inhibition. The aim of our work was to characterize the inhibitory effect of glutamate in the LC.Experimental approach:  Single‐unit extracellular and patch‐clamp recordings were performed to examine glutamate responses in rat brain slices containing the LC.Key results:  Glutamate caused an initial activation followed by a late post‐activation inhibition (PAI). Both effects were blocked by an AMPA/kainate receptor antagonist but not by NMDA or metabotropic glutamate receptor antagonists. All glutamate receptor agonists were able to activate neurons, but only AMPA and quisqualate caused inhibition. In neurons clamped at −60 mV, glutamate and AMPA induced inward, followed by outward, currents, with the latter reversing polarity at −110 mV. Glutamate‐induced PAI was not modified by α2‐adrenoceptor, µ opioid, A1 adenosine and GABAA/B receptor antagonists or Ca2+‐dependent release blockade, but it was reduced by raising the extracellular K+ concentration. Glutamate‐induced PAI was not affected by several potassium channel, Na+/K+ pump, PKC and neuronal NO synthase inhibitors or lowering the extracellular Ca2+ concentration. The Na+‐activated K channel opener bithionol concentration‐dependently potentiated glutamate‐induced PAI, whereas partial (80%) Na+ replacement reduced glutamate‐ and AMPA‐induced PAI. Finally, reverse transcription polymerase chain reaction assays showed the presence of mRNA for the Ca2+‐impermeable GluR2 subunit in the LC.Conclusions and implications:  Glutamate induces a late PAI in the LC, which may be mediated by a novel postsynaptic Na+‐dependent K+ current triggered by AMPA/kainate receptors.Mandarin translation of abstract
Post‐conditioning restores pre‐ischaemic receptor coupling in rat isolated hearts
Authors: Schreckenberg Rolf , Maier Thorsten , Schlüter Klaus‐Dieter 
Published: February 2009

Background and purpose:  Ischaemic preconditioning (IPC) and ischaemic post‐conditioning (IPoC) activate signal transduction pathways that are also involved in receptor de‐ and re‐sensitization such as phosphatidylinositol (PI) 3‐kinase. Therefore, IPC and IPoC may affect post‐infarct receptor coupling.Experimental approach:  Rat isolated hearts (Langendorff mode, constant flow) were exposed to 45 min flow arrest followed by 120 min reperfusion, including IPC or IPoC. Control hearts were perfused without a 45 min flow arrest. Left ventricular developed pressure (LVdevP) was determined. Thirty min after reperfusion, hearts were exposed to parathyroid hormone‐related peptide (PTHrP) or isoprenaline for 10 min to monitor receptor responsiveness. Reperfusion injury was quantified by enzyme release.Key results:  IPC and IPoC significantly reduced enzyme release compared with ischaemia and reperfusion alone by 75% and 62% respectively. Wortmannin or chelerythrine inhibiting either PI 3‐kinase or protein kinase C, respectively, attenuated protection. Application of PTHrP 30 min after reperfusion did not change LVdevP in hearts exposed to ischaemia (+1 ± 11%), but IPoC restored the normal and non‐ischaemic response to PTHrP characterized by a negative inotropism (−8.3 ± 3.9% and −12.9 ± 6.1%). IPC restored a small negative inotropic effect (−4.4 ± 4.7%). Application of a PTHrP receptor antagonist during the 45 min flow arrest attenuated receptor desensitization (ΔLVdevP: −6.1 ± 1.7%). Wortmannin but not chelerythrine attenuated the re‐sensitizing effect of IPoC on post‐ischaemic receptor coupling (ΔLVdevP: +6.2 ± 10.5 and −15.0 ± 7.7%). As observed with PTHrP receptors, IPoC restored β‐adrenoceptors (ΔLVdevP: +9.3 ± 11.8% vs. 62.3 ± 15.8%).Conclusions and implications:  IPoC restores PTHrP receptor coupling in a PI 3‐kinase‐dependent way. A similar mechanism may allow β‐adrenoceptor re‐sensitization.
Protopanaxadiol and protopanaxatriol bind to glucocorticoid and oestrogen receptors in endothelial cells
Authors: Leung Kar Wah , Leung Fung Ping , Mak Nai Ki , Tombran‐Tink Joyce , Huang Yu , Wong Ricky NS 
Published: February 2009

Background and purpose: Ginsenosides are used widely for medicinal purposes, but the mechanisms of their action are still unclear, although there is some evidence that these effects are mediated by nuclear receptors. Here we examined whether two metabolites of ginsenoside, protopanaxadiol (g‐PPD) and protopanaxatriol (g‐PPT), could modulate endothelial cell functions through the glucocorticoid receptor (GR) and oestrogen receptor (ER).Experiment approaches: The effects of g‐PPD and g‐PPT on intracellular calcium ion concentration ([Ca2+]i) and nitric oxide (NO) production in human umbilical vein endothelial cells (HUVECs) were measured using Fura‐2‐acetoxymethyl ester, 4‐amino‐5‐methylamino‐2′,7′‐difluorofluorescein and Griess reagent. Effects on expression of GR and ER isoforms in HUVECs were determined using reverse transcriptase‐/real‐time PCR and immunocytochemistry. Phosphorylation of endothelial NO synthase (eNOS) was assessed by Western blotting.Results: Ginsenoside protopanaxadiol and g‐PPT increased [Ca2+]i, eNOS phosphorylation and NO production in HUVECs, which were inhibited by the GR antagonist, RU486, the ER antagonist, ICI 182,780 and siRNA targeting GR or ERβ. The NO production was Ca2+‐dependent and the [Ca2+]ielevation in HUVECs resulted from both intracellular Ca2+release and extracellular Ca2+influx.Conclusions and implications: Ginsenoside protopanaxadiol and g‐PPT were functional ligands for both GR and ERβ, through which these ginsenoside metabolites exerted rapid, non‐genomic effects on endothelial cells.Mandarin translation of abstract
Pharmacology of α7 nicotinic acetylcholine receptor mediated extracellular signal‐regulated kinase signalling in PC12 cells
Authors: Kouhen R El , Hu M , Anderson DJ , Li J , Gopalakrishnan M 
Published: February 2009

Background and purpose: Neuronal nicotinic acetylcholine receptors (nAChR) can modulate cell survival and memory processing. The involvement of specific nAChR subtypes in downstream signalling events has been ill defined thus far, because of a lack of subtype‐selective ligands. In this study, we investigated activation and modulation of α7 nAChR‐mediated phosphorylation of extracellular signal‐regulated kinases (ERK1/2) in PC12 cells, using selective agonists and positive allosteric modulators.Experimental approach: We used undifferentiated PC12 cells endogenously expressing α7 nAChR for both biochemical and functional studies. ERK phosphorylation changes were measured by using a novel In‐Cell Western procedure. α7 nAChR‐mediated Ca2+signalling was determined by using the fluorometric imaging plate reader assay.Key results: Robust induction of ERK phosphorylation followed exposure of PC12 cells to the selective agonist PNU‐282987 in the presence of the α7 nAChR modulator PNU‐120596. ERK phosphorylation was transient and was attenuated by the selective antagonist methyllycaconitine. Consistent with allosteric modulation of α7 nAChRs, PNU‐120596 enhanced both the agonist potency and efficacy in activating ERK. Moreover, α7 nAChR agonists could be quantitatively differentiated based on their potency in activating ERK signalling. The rank order of potencies correlated fairly well with the corresponding bindingKivalues of these α7 nAChR agonists.Conclusions and implications: The present work extends previous observations demonstrating the involvement of α7 nAChRs in ERK1/2 phosphorylation in PC12 cells. The In‐Cell Western procedure allowed a detailed investigation of α7 nAChR function and downstream ERK signalling in response to agonist and allosteric modulators.Mandarin translation of abstract