bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cell culturing in a three‐dimensional matrix affects the localization and properties of plasma membrane cholesterol
Authors: Stefanova Nadezhda , Staneva Galya , Petkova Diana , Lupanova Teodora , Pankov Roumen , Momchilova Albena 
Published: July 2009

AbstractMost in vitro studies use 2‐dimensional (2D) monolayer cultures, where cells are forced to adjust to unnatural substrates that differ significantly from the natural 3‐dimensional (3D) extracellular matrix that surrounds cells in living organisms. Our analysis demonstrates significant differences in the cholesterol and sphingomyelin content, structural organization and cholesterol susceptibility to oxidation of plasma membranes isolated from cells cultured in 3D cultures compared with conventional 2D cultures. Differences occurred in the asymmetry of cholesterol molecules and the physico‐chemical properties of the 2 separate leaflets of plasma membranes in 2D and 3D cultured fibroblasts. Transmembrane distribution of other membrane phospholipids was not different, implying that the cholesterol asymmetry could not be attributed to alterations in the scramblase transport system. Differences were also established in the chemical activity of cholesterol, assessed by its susceptibility to cholesterol oxidase in conventional and “matrix” cell cultures. The influence of plasma membrane sphingomyelin and phospholipid content on cholesterol susceptibility to oxidation in 2D and 3D cells was investigated with exogenous sphingomyelinase (SMase) and phospholipase C (PLC) treatment. Sphingomyelin was more effective than membrane phospholipids in protecting cholesterol from oxidation. We presume that the higher cholesterol/sphingomyelin molar ratio is the reason for the higher rate of cholesterol oxidation in plasma membranes of 3D cells.
Vascular endothelial growth factor (VEGF) affects processing of amyloid precursor protein and β‐amyloidogenesis in brain slice cultures derived from transgenic Tg2576 mouse brain
Authors: Bürger Susanne , Noack Monika , Kirazov Ludmil P. , Kirazov Evgeni P. , Naydenov Cyrill L. , Kouznetsova Elena , Yafai Yousef , Schliebs Reinhard 
Published: July 2009

AbstractThe up‐regulation of the angiogenic vascular endothelial growth factor (VEGF) in brains of Alzheimer patients in close relationship to β‐amyloid (Aβ) plaques, suggests a link of VEGF action and processing of the amyloid precursor protein (APP). To reveal whether VEGF may affect APP processing, brain slices derived from 17‐month‐old transgenic Tg2576 mice were exposed with 1 ng/ml VEGF for 6, 24, and 72 h, followed by assessing cytosolic and membrane‐bound APP expression, level of both soluble and fibrillar Aβ‐peptides, as well as activities of α‐ and β‐secretases in brain slice tissue preparations.Treatment of brain slices with VEGF did not significantly affect the expression level of APP, regardless of the exposure time studied. In contrast, VEGF exposure of brain slices for 6 h reduced the formation of soluble, SDS extractable Aβ(1–40) and Aβ(1–42) as compared to brain slice cultures incubated in the absence of any drug, while the fibrillar Aβ peptides did not change significantly. This effect was less pronounced 24 h after VEGF exposure, but was no longer detectable when brain slices were exposed by VEGF for 72 h, which indicates an adaptive response to chronic VEGF exposure. The VEGF‐mediated reduction in Aβ formation was accompanied by a transient decrease in β‐secretase activity peaking 6 h after VEGF exposure. To reveal whether the VEGF‐induced changes in soluble Aβ‐level may be due to actions of VEGF on Aβ fibrillogenesis, the fibrillar status of Aβ was examined using the thioflavin‐T binding assay. Incubation of Aβ preparations obtained from Tg2576 mouse brain cortex, in the presence of VEGF slightly decreased the fibrillar content with increasing incubation time up to 72 h. The data demonstrate that VEGF may affect APP processing, at least in vitro, suggesting a role of VEGF in the pathogenesis of Alzheimer's disease.
Expression of the neural specific protein, GAP‐43, dramatically lengthens the cell cycle in fibroblasts
Authors: Zhao Junpeng , Yao Yajuan , Xu Changlei , Jiang Xiaohua , Xu Qunyuan 
Published: July 2009

AbstractIt has been demonstrated that during neurogenesis in the mammalian brain, cell‐cycle lengthening in neuronal progenitors may cause them to switch from proliferation to neuron‐generating division. However, little is known about the cellular mechanisms involved in lengthening of the cell cycle. Growth‐associated protein‐43 (GAP‐43) is a nervous system‐specific protein whose expression in proliferating neuroblasts is related to neurogenesis. In this study, we investigated the effect of GAP‐43 on cell‐cycle progression in transgenic fibroblast cells. Using cumulative bromodeoxyuridine labeling, cell‐cycle kinetics in GAP‐43‐transgenic and control NIH 3T3 cells were analyzed. Our data demonstrate that expression of GAP‐43 in fibroblasts results in lengthening of the cell cycle compared to control fibroblasts. The mechanism by which GAP‐43 mediated this effect appeared to involve increasing the time spent by the cells in the G1 phase of the cell cycle.
Adversative conjunction choice in Russian (no, da, odnako): Semantic and syntactic influences on lexical selection
Authors: Kapatsinski Vsevolod 
Published: July 2009

AbstractThis article presents a multivariate analysis of adversative conjunction choice (among no, da, and odnako) in Russian, drawing implications for sentence production and semantic theory. The two main factors shown to influence conjunction choice are the types of the conjoined constituents and the semantic subtype of the adversative relation. One of the conjunctions, da, is favored when the conjoined elements are of different syntactic types and disfavored when they are of the same type, which is argued to suggest that the conjunction is chosen at a point in sentence production when the types of both of the conjoined constituents are known (Uryson, 2006). In addition, the conjunction da is heavily favored by the “preventive” adversative meaning (Sannikov, 1989:177; Serebrjanaja, 1976), as in I would go but I don't have the money. This quantitative meaning-construction association is argued to support the view that the preventive adversative is a distinct semantic subtype of adversativity (Payne, 1985; contra Foolen, 1991:84).
Phonological variation and change in Australian and New Zealand Sign Languages: The location variable
Authors: Schembri Adam , McKee David , McKee Rachel , Pivac Sara , Johnston Trevor , Goswell Della 
Published: July 2009

AbstractIn this study, we consider variation in a class of signs in Australian and New Zealand Sign Languages that includes the signsthink, name, andclever. In their citation form, these signs are specified for a place of articulation at or near the signer's forehead or above, but are sometimes produced at lower locations. An analysis of 2667 tokens collected from 205 deaf signers in five sites across Australia and of 2096 tokens collected from 138 deaf signers from three regions in New Zealand indicates that location variation in these signs reflects both linguistic and social factors, as also reported for American Sign Language (Lucas, Bayley, & Valli, 2001). Despite similarities, however, we find that some of the particular factors at work, and the kinds of influence they have, appear to differ in these three signed languages. Moreover, our results suggest that lexical frequency may also play a role.
ECoG-based short-range recurrent stimulation techniques to stabilize tissue at risk of progressive damage: Theory based on clinical observations
Authors: Dahlem Markus , Schneider Felix , Dreier Jens , Strong Anthony , Schoell Eckehard 
Published: July 2009

AbstractWe introduce theoretical concepts based on chaos control to stabilize in acute stroke the tissue at risk of progressive damage by preventing adverse effects of waves of mass neuronal depolarization. Moreover, we present clinical electrocorticography (ECoG) recordings of relevant signals suggested for the feedback control. The recordings are performed in combination with novel subdural opto-electrode technology for simultaneous laser-Doppler flowmetry in patients with aneurysmal subarachnoid haemorrhage (aSAH). In aSAH patients waves of spreading depolarization (SD) have a high incidence and cause hypoxia in tissue at risk, and, importantly, the haemodynamic response is the inverse of that seen in healthy tissue. In previous clinical studies, clusters of prolonged SDs have been measured in aSAH patients in close proximity to structural brain damage as assessed by neuroimaging, and, in theoretical studies, a mechanism was presented, suggesting how a failure of internal feedback could be a putative mechanism of such SD cluster patterns in acute stroke. This failing internal feedback control is now suggested to be replaced by ECoG-based short-range recurrent functional stimulation that initiates the normal hyperperfusion haemodynamic response in a demand-controlled way and stabilizes the tissue at risk during the critical phase of SD passage. The suggested method has three key features: (i) it is short-range, i.e., in the order of the distance of the ECoG electrode strip, (ii) it is demand-controlled, and (iii) it uses no prior knowledge of the target state, in particular, it adapts to conditions in the healthy physiological range. On-demand type stimulation provides minimal invasive feedback as the control force is off when the target state is reached, i.e., the tissue at risk is without SD or it is back to the physiological range (out of risk). These last two features (ii-iii) are shared with classical methods of chaos control, where major progress was made in the last years with respect to extensions for spatio-temporal wave patterns. A detailed bifurcation analysis of the nonlinear model is presented, in particular, the SD cluster forming cortical state is suggested to be caused by a delay-induced saddle-node bifurcation.
Increased late sodium currents are related to transcription of neuronal isoforms in a pressure‐overload model
Authors: Xi Yutao , Wu Geru , Yang Lin , Han Ke , Du Yuan , Wang Tingzhong , Lei Xinjun , Bai Xiaojun , Ma Aiqun 
Published: July 2009

AimsThe late and persistent sodium current (INa) has been identified as a target for anti‐arrhythmia drugs in patients with heart failure (HF). However, the underlying mechanism of late INa (INaL) production remains uncertain. We hypothesized that transcriptional alteration among sodium channel (NaCh) isoforms may contribute to INaL in failing cardiomyocytes.Methods and resultsPressure‐overload rat models were created by 16‐week constriction of the ascending aorta (HF). Haemodynamic and electrocardiographic variables were studied in sham operation and HF rats. Action potential (AP) and INa were recorded using whole‐cell patch‐clamp techniques. The expression of various NaCh isoforms was evaluated by immunocytochemistry, RT‐PCR, and western blot. The HF group exhibited left ventricular enlargement, systolic dysfunction, and prolongation of QTc intervals (P < 0.05). Current‐clamp recording indicated that AP durations (APDs) were more sensitive to tetrodotoxin. Voltage‐clamp recordings showed that INaL was increased (−1.54 ± 0.43 vs. −1.08 ± 0.38 pA/pF, P < 0.01) in HF, but transient INa (INaT) density was decreased (−14.61 ± 2.30 vs. −26.15 ± 5.17 pA/pF, P < 0.01). Correspondingly, the relative mRNA levels of the neuronal isoforms SCN1a and SCN8a increased 2.5‐ and 2.7‐fold, respectively; SCN3a did not change, whereas SCN5a decreased by ~60% in HF. Protein levels paralleled their mRNA expression.ConclusionThe up‐regulated expression of the neuronal NaCh isoforms SCN1a and SCN8a could be one mechanism of INaL production, which may contribute to prolongation of APD in the failing heart.
Exploration of Sugar Functionality in Sugar‐Snap and Wire‐Cut Cookie Baking: Implications for Potential Sucrose Replacement or Reduction
Authors: Kweon Meera , Slade Louise , Levine Harry , Martin Ron , Souza Edward 
Published: July 2009

ABSTRACTThe sugar series—xylose, glucose, fructose, and sucrose—can be used diagnostically to explore the effects of sugar type on differential scanning calorimetry (DSC), Rapid Visco‐Analyser (RVA), and cookie baking performance because of the differences in glass‐forming abilities (related to plasticization) and solubility parameters (related to solvent preference) of different sugars. Sugar concentration (% S), total solvent (TS), and dough formulation defined a core experimental design for cookie baking with the four sugar types and two baking methods. Although wire‐cut cookie baking (66% S and 64 TS) showed the same trends as sugar‐snap cookie baking (73% S and 79 TS) for diameter, height, and moisture content, the wire‐cut formulation enabled greater discrimination among the effects of different sugar types on dough and cookie responses. Use of two different crystal sizes of sucrose confirmed the dominant impact of both gluten development during dough mixing and starch pasting during cookie baking on collapse: the greater rate of dissolution of smaller sucrose crystals resulted in greater surface crack for sugar‐snap cookies, and lower height for wire‐cut cookies. Because the historical definition of an “excellent quality cookie flour” is based on the performance of a flour in a cookie formulated with sucrose, the effect of sugar type on cookie making is to transform the apparent baking performance of a flour. Whereas formulation with sucrose optimizes the flour performance for cookie baking, formulation with xylose exaggerates the worst aspects of cookie flour functionality and makes even the best cookie flour look like a “poor quality cookie flour”. Use of solvent retention capacity (SRC), DSC, RVA, and wire‐cut cookie baking as predictive research tools demonstrated that identification of a flour with an optimized SRC pattern is the key to successful mitigation of the detrimental effects of sucrose replacement on cookie processing and product attributes.
Shoot Na+ Exclusion and Increased Salinity Tolerance Engineered by Cell Type–Specific Alteration of Na+ Transport in Arabidopsis
Authors: Møller Inge S. , Gilliham Matthew , Jha Deepa , Mayo Gwenda M. , Roy Stuart J. , Coates Juliet C. , Haseloff Jim , Tester Mark 
Published: July 2009

Abstract
Soil salinity affects large areas of cultivated land, causing significant reductions in crop yield globally. The Na+ toxicity of many crop plants is correlated with overaccumulation of Na+ in the shoot. We have previously suggested that the engineering of Na+ exclusion from the shoot could be achieved through an alteration of plasma membrane Na+ transport processes in the root, if these alterations were cell type specific. Here, it is shown that expression of the Na+ transporter HKT1;1 in the mature root stele of Arabidopsis thaliana decreases Na+ accumulation in the shoot by 37 to 64%. The expression of HKT1;1 specifically in the mature root stele is achieved using an enhancer trap expression system for specific and strong overexpression. The effect in the shoot is caused by the increased influx, mediated by HKT1;1, of Na+ into stelar root cells, which is demonstrated in planta and leads to a reduction of root-to-shoot transfer of Na+. Plants with reduced shoot Na+ also have increased salinity tolerance. By contrast, plants constitutively expressing HKT1;1 driven by the cauliflower mosaic virus 35S promoter accumulated high shoot Na+ and grew poorly. Our results demonstrate that the modification of a specific Na+ transport process in specific cell types can reduce shoot Na+ accumulation, an important component of salinity tolerance of many higher plants.
Phylogenomic Analysis Demonstrates a Pattern of Rare and Ancient Horizontal Gene Transfer between Plants and Fungi
Authors: Richards Thomas A. , Soanes Darren M. , Foster Peter G. , Leonard Guy , Thornton Christopher R. , Talbot Nicholas J. 
Published: July 2009

Abstract
Horizontal gene transfer (HGT) describes the transmission of genetic material across species boundaries and is an important evolutionary phenomenon in the ancestry of many microbes. The role of HGT in plant evolutionary history is, however, largely unexplored. Here, we compare the genomes of six plant species with those of 159 prokaryotic and eukaryotic species and identify 1689 genes that show the highest similarity to corresponding genes from fungi. We constructed a phylogeny for all 1689 genes identified and all homolog groups available from the rice (Oryza sativa) genome (3177 gene families) and used these to define 14 candidate plant-fungi HGT events. Comprehensive phylogenetic analyses of these 14 data sets, using methods that account for site rate heterogeneity, demonstrated support for nine HGT events, demonstrating an infrequent pattern of HGT between plants and fungi. Five HGTs were fungi-to-plant transfers and four were plant-to-fungi HGTs. None of the fungal-to-plant HGTs involved angiosperm recipients. These results alter the current view of organismal barriers to HGT, suggesting that phagotrophy, the consumption of a whole cell by another, is not necessarily a prerequisite for HGT between eukaryotes. Putative functional annotation of the HGT candidate genes suggests that two fungi-to-plant transfers have added phenotypes important for life in a soil environment. Our study suggests that genetic exchange between plants and fungi is exceedingly rare, particularly among the angiosperms, but has occurred during their evolutionary history and added important metabolic traits to plant lineages.
Identification of amino acid residues of the pheromone‐binding domain of the transcription factor TraR that are required for positive control
Authors: Costa Esther D. , Cho Hongbaek , Winans Stephen C. 
Published: July 2009

SummaryGenes required for replication and for conjugal transfer of the Agrobacterium tumefaciens Ti plasmid are regulated by the quorum sensing transcription factor TraR, whose N‐terminal domain binds to the pheromone 3‐oxo‐octanoylhomoserine lactone (OOHL) and whose C‐terminal domain binds to specific DNA sequences called tra boxes. Here, we constructed 117 mutants, altering 103 surface‐exposed amino acid residues of the TraR N‐terminal domain. Each mutant was tested for activation of the traI promoter, where TraR binds to a site centred 45 nucleotides upstream of the transcription start site, and of the traM promoter, where TraR binds a site centred 66 nucleotides upstream. Alteration of 18 residues blocked activity at the traI promoter. Of these, alteration at three positions impaired TraR abundance or DNA binding, leaving 15 residues that are specifically needed for positive control. Of these 15 residues, nine also blocked or reduced activity at the traM promoter, while six had no effect. Amino acid residues required for activation of both promoters probably contact the C‐terminal domain of the RNA polymerase α subunit, while residues required only for traI promoter activation may contact another RNA polymerase component.
Conspecifics and Their Posture Influence Site Choice and Oviposition in the DamselflyArgia moesta
Authors: Byers Catherine J. , Eason Perri K. 
Published: July 2009

AbstractFinding a suitable oviposition site can be costly because of energy and time requirements, and ovipositioning can be dangerous because of the risk of predation and harassment by males. The damselflyArgia moestaoviposits, contact‐guarded by her mate, on vegetation in streams. Oviposition aggregations are commonly observed in this species, despite their territorial nature during other behaviors. We conducted experiments in the field to test the hypothesis that aggregations are the result of conspecific attraction. In the first experiment, two oviposition sites (sycamore leaves) were provided, one with models of ovipositing pairs, and one without. In the second experiment, one leaf again had ovipositing models, while the other had models of uncoupled males and females in a resting posture. In both experiments, damselfly pairs preferred the site with ovipositing models. In general, they visited the ovipositing models first more often than expected by chance, stayed longer there, were more likely to oviposit there, and laid a greater total number of eggs there. These results support the hypothesis that conspecific attraction is responsible for ovipositing aggregations inA. moestaand that posture is an important cue for attraction. Using conspecific cues could be a beneficial strategy to save in search costs while taking advantage of the presence of ovipositing conspecifics to dilute the effects of harassment and predation.
Males Exhibit Novel Relationships of Dominance with Nest Departure in the Social Paper WaspMischocyttarus mastigophorus(Hymenoptera: Vespidae)
Authors: Molina Yamile , O’Donnell Sean 
Published: July 2009

AbstractIn many animal societies, an individual’s opportunities to reproduce correspond to their position in a dominance hierarchy. In primitively eusocial paper wasps, female social dominance and direct reproduction are positively associated with taking food from nest mates, but both negatively correlate with foraging flights. Female paper wasps reproduce by laying eggs in their nest, while males reproduce by leaving the nest to copulate. Males ofMischocyttarus mastigophorusare unusual because they reside on their natal nests for prolonged periods, and males direct aggression towards female nestmates.Mischocyttarus mastigophorusmales provide an opportunity to further analyse the relationships between dominance, nutrition and nest departure. We found males’ rates of social aggression, food taking behaviour, and rates of nest departure were positively correlated. Furthermore, males that initiated aggression at younger ages also began flying earlier, and males engaged in all three behaviours at younger ages than females. Male social aggression may lead to nutrient acquisition, which enable males to depart from the nest. We hypothesise that male nest departure could be adaptive if it increases male mating opportunities. This could account for the positive relationship between dominance and nest departure for males.
No Coolidge Effect in Decorated Crickets
Authors: Gershman Susan N. , Sakaluk Scott K. 
Published: July 2009

AbstractFemale decorated crickets, Gryllodes sigillatus, obtain genetic benefits by mating with different males and, when given a choice, prefer novel males over previous mates. It is unknown, however, whether males exhibit a similar preference for novel females. Although female crickets control copulation, there are at least two ways in which males can exercise choice: (1) the amount of courtship directed towards prospective mates and (2) the size of the spermatophore transferred to the female at mating. To determine whether males devote more courtship effort to novel females while controlling for female behavioral cues, male courtship effort toward two dead females, one, a previous mate and the other, a novel female, was measured. To determine whether males manufacture larger spermatophores when paired with novel females, males were mated to novel or previous mates, and the different components of the spermatophore weighed. Males did not spend more time courting dead novel females than previous mates. There was no difference in the latency to remating of males confined with novel females and those paired with previous mates, and there was no difference in the mass of spermatophores transferred to novel and familiar females. Contrary to previous studies in other taxa, this study suggests that male crickets do not prefer novel mates and thus, are not subject to the Coolidge effect. Although mating with novel females may be beneficial to males, selection on males to identify and discriminate against previous mates may be relaxed because of a strong female preference for novel males.