bluuebunny/crossref_metadata_2025_split huggingface dataset:
Differentiated roles for MreB‐actin isologues and autolytic enzymes in Bacillus subtilis morphogenesis
Authors: Domínguez‐Cuevas Patricia , Porcelli Ida , Daniel Richard A. , Errington Jeff 
Published: July 2013

SummaryCell morphogenesis in most bacteria is governed by spatiotemporal growth regulation of the peptidoglycan cell wall layer. Much is known about peptidoglycan synthesis but regulation of its turnover by hydrolytic enzymes is much less well understood. Bacillus subtilis has a multitude of such enzymes. Two of the best characterized are CwlO and LytE: cells lacking both enzymes have a lethal block in cell elongation. Here we show that activity of CwlO is regulated by an ABC transporter, FtsEX, which is required for cell elongation, unlike cell division as in Escherichia coli. Actin‐like MreB proteins are thought to play a key role in orchestrating cell wall morphogenesis. B. subtilis has three MreB isologues with partially differentiated functions. We now show that the three MreB isologues have differential roles in regulation of the CwlO and LytE systems and that autolysins control different aspects of cell morphogenesis. The results add major autolytic activities to the growing list of functions controlled by MreB isologues in bacteria and provide new insights into the different specialized functions of essential cell wall autolysins.
Mycobacterium tuberculosis EspB binds phospholipids and mediates EsxA‐independent virulence
Authors: Chen Jeffrey M. , Zhang Ming , Rybniker Jan , Boy‐Röttger Stefanie , Dhar Neeraj , Pojer Florence , Cole Stewart T. 
Published: July 2013

SummaryThe type‐VII ESX‐1 secretion apparatus, encoded by the esx‐1 genetic locus, is essential for the export of EsxA and EsxB, two major virulence factors of Mycobacterium tuberculosis. ESX‐1 also requires the products of the unlinked espACD operon for optimal function and these proteins are considered integral parts of the secretion apparatus. Here we show that the espACD operon is not necessary for the secretion of EspB, another ESX‐1 substrate, and this unimpeded secretion of EspB is associated with significant residual virulence. Upon further investigation, we found that purified EspB can facilitate M. tb virulence even in the absence of EsxA and EsxB, and may do so by binding the bioactive phospholipids phosphatidic acid and phosphatidylserine, both of which are potent bioactive molecules with prominent roles in eukaryotic cell signalling. Our findings provide new insights into the impact of the espACD operon on the ESX‐1 apparatus and reveal a distinct virulence function for EspB with novel implications in M. tb‐host interactions.
Psychosocial factors in people with chronic kidney disease prior to renal replacement therapy
Authors: McKercher Charlotte , Sanderson Kristy , Jose Matthew D 
Published: July 2013

AbstractIncreasing evidence implicates psychosocial factors including depression, anxiety, perceived social support and health‐related quality of life in the pathophysiology of various chronic diseases. Research examining the psychosocial aspects of kidney disease has focussed predominantly on depressive disorders in dialysis patients where they are independently associated with increased risk of mortality and poor health‐related quality of life. In contrast, studies examining the influence of psychosocial factors in people with chronic kidney disease (CKD) prior to the initiation of renal replacement therapy are sparse. Limited data indicate that clinical depression and depressive symptoms are common and may independently predict progression to dialysis, hospitalization and death. In contrast, the influence of anxiety disorders, lower perceived social support and impaired health‐related quality of life on the clinical course of CKD have received little attention. Large‐scale prospective cohort studies are needed to clarify the burden and prognostic impact of these factors in this vulnerable population. Given the escalating burden of CKD worldwide examining the role of these potentially modifiable risk factors is crucial. Identifying and implementing targeted interventions in order to prevent or delay the progression of CKD and improve quality of life will be a major challenge.
Genetic roadmap of the Arctic: plant dispersal highways, traffic barriers and capitals of diversity
Authors: Eidesen Pernille Bronken , Ehrich Dorothee , Bakkestuen Vegar , Alsos Inger Greve , Gilg Oliver , Taberlet Pierre , Brochmann Christian 
Published: July 2013

Summary

We provide the first comparative multispecies analysis of spatial genetic structure and diversity in the circumpolar Arctic using a common strategy for sampling and genetic analyses. We aimed to identify and explain potential general patterns of genetic discontinuity/connectivity and diversity, and to compare our findings with previously published hypotheses.

We collected and analyzed 7707 samples of 17 widespread arctic–alpine plant species for amplified fragment length polymorphisms (AFLPs). Genetic structure, diversity and distinctiveness were analyzed for each species, and extrapolated to cover the geographic range of each species. The resulting maps were overlaid to produce metamaps.

The Arctic and Atlantic Oceans, the Greenlandic ice cap, the Urals, and lowland areas between southern mountain ranges and the Arctic were the strongest barriers against gene flow. Diversity was highest in Beringia and gradually decreased into formerly glaciated areas. The highest degrees of distinctiveness were observed in Siberia.

We conclude that large‐scale general patterns exist in the Arctic, shaped by the Pleistocene glaciations combined with long‐standing physical barriers against gene flow. Beringia served as both refugium and source for interglacial (re)colonization, whereas areas further west in Siberia served as refugia, but less as sources for (re)colonization.
Defibrillation Threshold Testing Does Not Predict Clinical Outcomes during Long‐Term Follow‐Up: A Meta‐Analysis
Authors: STAVRAKIS STAVROS , PATEL NISHIT H. , REYNOLDS DWIGHT W. 
Published: July 2013

BackgroundDefibrillation threshold (DFT) testing at the time of implantable cardioverter defibrillator (ICD) implantation is widely used in clinical practice, but reliable data supporting its routine use are lacking. We undertook a meta‐analysis to evaluate the efficacy of DFT testing compared to no DFT testing at the time of ICD implantation.MethodsWe searched the MEDLINE and EMBASE databases for studies evaluating the effect of DFT testing on total mortality and ventricular arrhythmias during follow‐up. Risk ratios (RR) with 95% confidence intervals (CI) were calculated using random effects modeling.ResultsEight studies involving 5,020 patients (3,068 undergoing DFT and 1,952 not undergoing DFT) were included. Of those, only one study was randomized. Reasons for not performing DFT included patient characteristics (four studies), center's standard practice (three studies), or randomization (one study). Median follow‐up was 24 months. Overall, the quality of the included studies was rather poor. On the basis of the pooled estimate across the studies, DFT testing did not reduce total mortality or ventricular arrhythmias at follow‐up (RR = 0.94, 95% CI 0.74–1.21; P = 0.65 and RR = 1.19, 95% CI 0.85–1.68; P = 0.30, respectively). No individual study had a major impact on the estimated RR or the statistical significance based on a sensitivity analysis.ConclusionRecognizing the limited quality of current studies in the area of DFT testing and outcomes, available data suggest that DFT testing at the time of ICD implantation does not appear to predict total mortality and ventricular arrhythmias during follow‐up. Large randomized controlled trials, adequately powered to detect clinical outcomes, are warranted.
Does Low Birth Weight Affect P‐Wave and QT Dispersion in Childhood?
Authors: AKYUZ AYDIN , ALPSOY SEREF , AKKOYUN DURSUN CAYAN , NALBANTOGLU BURCIN , OZDILEK BURCU , DONMA MUSTAFA METIN 
Published: July 2013

BackgroundThe aim of our study is to investigate the effects of low birth weight (LBW) on atrial conduction and ventricular repolarization in children by using P‐wave dispersion (Pw‐d) and QT dispersion (QT‐d) analyses. These effects have not yet been studied in detail in LBW children.MethodsFifty LBW children and 70 normal birth weight (NBW) children were enrolled in this cross‐sectional controlled study. The Pw‐d and QT‐d of the LBW and NBW children were investigated. Independent Student's t‐test, Mann‐Whitney U test, and χ2 test were performed to compare these two groups. Stepwise multiple regression analysis was performed to investigate whether there was a relationship between P‐wave indices, QT derivatives, anthropometric and clinical features, and echocardiographic parameters.ResultsAge, gender, body mass index, waist circumferences, systolic and diastolic blood pressure, and echocardiographic measurements were similar between the LBW group and the NBW group (all P values > 0.05). The following findings were recorded for the LBW and NBW groups, respectively: the Pw‐d (30 [10–50] ms vs 30 [10–50] ms, P = 0.977), QT‐d (20 [10–50] ms vs 30 [15–50] ms, P = 0.561), and QTc‐d (26 [14–54] ms vs 33 [17–62] ms, P = 0.866). No significant difference was found in Pw‐d, QT‐d, and QTc‐d in comparison between the groups (all P values > 0.05). Pw‐d was related to left atrial diameter and QTc‐d was associated with left ventricle mass index even though they were within the normal range.ConclusionCompared with the NBW group, no significant difference was found in both atrial conduction and ventricular repolarization features in LBW children.
Ibutilide Increases the Variability and Complexity of Atrial Fibrillation Electrograms: Antiarrhythmic Insights Using Signal Analyses
Authors: BIVIANO ANGELO B. , CIACCIO EDWARD J. , GABELMAN TARA , WHANG WILLIAM , GARAN HASAN 
Published: July 2013

IntroductionIntravenous ibutilide is used to convert atrial fibrillation (AF) to sinus rhythm (SR) due to its Class III antiarrhythmic mechanisms. However, the effects of ibutilide on local electrograms (EGMs) during AF have not been elucidated.Methods and ResultsWe used EGM analysis techniques to characterize how ibutilide administration changes the frequency, morphology, and repeatability of AF EGM signals, thereby providing insight into ibutilide's antiarrhythmic mechanism of action. AF recordings were collected from 21 patients with AF, both before and after ibutilide administration. The effects of ibutilide on the following AF EGM parameters were assessed: (1) dominant frequency (DF), (2) variations in EGM amplitude and overall morphology, (3) repetition of EGM patterns, and (4) complexity of the AF frequency spectra. When comparing pre‐ versus post‐ibutilide administration EGMs, DF decreased from 5.45 Hz to 4.02 Hz (P < 0.0001). There was an increase in the variability of both AF EGM amplitudes (P = 0.003) and overall AF EGM morphologies (P = 0.003). AF EGM pattern repetitiveness decreased (P = 0.01), and the AF frequency spectral profile manifested greater complexity (P = 0.02).ConclusionsNovel EGM signal analysis techniques reveal that ibutilide administration causes increased complexity in the atrial electrical activation pattern with decreasing rate. These findings may be explained by the progressive destabilization of higher frequency, more homogeneous primary drivers of AF over the course of ibutilide administration, and/or less uniform propagation of atrial activation, until AF maintenance becomes more difficult and either transforms to atrial tachycardia or terminates to SR.
Adaptive radiation in the fossil record: a case study amongJurassic ammonoids
Authors: Neige Pascal , Dera Guillaume , Dommergues Jean‐Louis 
Published: July 2013

AbstractEvolutionary radiations have been extensively studied especially in the fossil record and in the context of postcrisis recoveries. The concept of adaptive radiation that emerges from this very broad topic explicitly involves the effect of adaptation driven by ecological opportunity and is considered to be of the foremost importance. It is essential to be able to detect adaptive radiation because it points up factors that predispose a clade to radiate. Adaptive radiation has received much attention in recent decades based mostly on studies dealing with recent clades, but data from the fossil record are still scarce. This study begins to fill this gap with the example ofLowerJurassic ammonoids (throughc. 8 Myr of history). A survey of several clades, using both taxonomic and disparity‐based approaches, shows that they diversified successively through time, but not systematically, in terms of species numbers and morphological variety. Some clades seem to have exhibited adaptive radiation and to have become rapidly extinct. One clade (which engendered nearly all post–LowerJurassic ammonoids) has a fossil record that begins with low diversity and disparity but is superseded by a sustained radiation pattern. The results are discussed in the light of theModernSynthesis and its continuation into anExtendedEvolutionarySynthesis.
Precambrian–Cambrian boundary interval occurrence and form of the enigmatic tubular body fossil Shaanxilithes ningqiangensis from the Lesser Himalaya of India
Authors: Tarhan Lidya G. , Hughes Nigel C. , Myrow Paul M. , Bhargava Om N. , Ahluwalia Arun D. , Kudryavtsev Anatoliy B. 
Published: July 2013

AbstractThe affinity of the Ediacaran fossil Shaanxilithes ningqiangensis and putatively related forms has long been enigmatic; over the past few decades, interpretations ranging from trace fossils to algae to metazoans of uncertain phylogenetic placement have been proposed. Combined morphological and geochemical evidence from a new occurrence of S. ningqiangensis in the Krol and Tal groups of the Lesser Himalaya of India indicates that S. ningqiangensis is not a trace fossil, but rather an organic‐walled tubular body fossil of unknown taxonomic affinity. Specimens consist of compressed organic cylindrical structures, characterized by extended, overlapping or fragmented iterated units. Where specimens intersect, overlapping rather than branching or intraplanar crossing is observed. Lithologic comparisons and sequence stratigraphic data all suggest a late Ediacaran age for the uppermost Krol Group and basalmost Tal Group. By extending the biogeographical distribution of S. ningqiangensis, hitherto confined to the Ediacaran of China and potentially Siberia, to the Precambrian–Cambrian boundary interval of India, this new occurrence of S. ningqiangensis expands the biostratigraphic utility of this enigmatic fossil to the inter‐regional and intercontinental scale. Moreover, study of these new and exceptionally preserved samples may help to significantly constrain the long‐debated problem of Shaanxilithes' affinity, elucidating its ‘problematic’ status and shedding new light upon the ecology and taphonomy of one of the most significant intervals in early life history.
Patient Characteristics of Neonatal Eosinophilic Pustulosis
Authors: Finelt Nika , Kristal Leonard 
Published: July 2013

AbstractA 10‐week old preterm infant boy presented with a pustular eruption of the face and blood eosinophilia. Histology demonstrated eosinophils without predominant follicular involvement. The lesions healed without intervention within 2 months. The presentation was consistent with neonatal eosinophilic pustulosis. We discuss the similarities between cases described in the literature and suggest that this entity affects a unique patient population of preterm infants.
Guanfacine‐Induced Lichenoid Drug Eruption in a Child with Autism and Attention Deficit Hyperactivity Disorder
Authors: Romanelli Mark , Rhodes Arthur 
Published: July 2013

AbstractLichenoid drug eruptions (LDEs) have a variety of medication causes. We report a case of a 5‐year‐old boy with autism and attention deficit hyperactivity disorder treated with guanfacine who developed pruritic lesions consistent with LDEs. Rechallenge was not attempted. There are several clinical and histopathologic clues that may distinguish LDEs from lichen planus.
Prospective associations between marital adjustment and life satisfaction
Authors: BE DANIEL , WHISMAN MARK A. , UEBELACKER LISA A. 
Published: July 2013

AbstractActor and partner effects for the 2‐year longitudinal associations between marital adjustment and life satisfaction were evaluated in a population‐based sample of middle‐aged and older adults (N = 1,385 couples). Results showed that (a) higher marital adjustment at baseline predicted higher life satisfaction at follow‐up, (b) higher life satisfaction at baseline predicted higher marital adjustment at follow‐up, (c) marital adjustment more strongly predicted life satisfaction than life satisfaction predicted marital adjustment for women, and (d) higher partner marital adjustment at baseline predicted higher life satisfaction at follow‐up. Results suggest that marital adjustment and life satisfaction influence one another in a bidirectional fashion and that the direction is predominantly from marital adjustment to life satisfaction in women.
Solar UV Exposure of Seafarers along Subtropical and Tropical Shipping Routes
Authors: Feister Uwe , Meyer Gabriele , Kirst Ulrich 
Published: July 2013

AbstractSeafarers working on decks of vessels at low latitudes are exposed to extremely high solar UV radiation. Their risk of developing skin cancer may be enhanced. Solar erythemal UV irradiance and exposure were measured for the first time on merchant vessels going along typical international routes at low latitudes. The measurements taken at horizontal incidence on the observation deck, and on different parts of the seaman (head, shoulder, chest and back) doing typical outdoor work show the highest portion (40–80% of horizontal exposure) incident on the head. 2 years of measurements of solar UV and VIS/NIR irradiance taken on the mast top of the Research Vessel METEOR were added to the data base. Radiative transfer model calculations were performed along all the routes with satellite‐based input data of ozone and aerosol for clear sky health‐effective radiation including vitamin D3 (VD3). Measured data show extremely high noontime UV index values up to 19 with clear sky, and up to 22 due to cloud scattering. Eight hours erythemal exposure values are more than double of typical midlatitude summer values. Based on the results, an algorithm is presented to derive a seafarer's personal erythemal exposure according to his/her personal record of sea service.
Growth responses and ion accumulation in the halophytic legume Prosopis strombulifera are determined by Na2SO4 and NaCl
Authors: Reginato M. , Sosa L. , Llanes A. , Hampp E. , Vettorazzi N. , Reinoso H. , Luna V. 
Published: July 2013

AbstractHalophytes are potential gene sources for genetic manipulation of economically important crop species. This study addresses the physiological responses of a widespread halophyte, Prosopis strombulifera (Lam.) Benth to salinity. We hypothesised that increasing concentrations of the two major salts present in soils of central Argentina (Na2SO4, NaCl, or their iso‐osmotic mixture) would produce distinct physiological responses. We used hydroponically grown P. strombulifera to test this hypothesis, analysing growth parameters, water relations, photosynthetic pigments, cations and anions. These plants showed a halophytic response to NaCl, but strong general inhibition of growth in response to iso‐osmotic solutions containing Na2SO4. The explanation for the adaptive success of P. strombulifera in high NaCl conditions seems to be related to a delicate balance between Na+ accumulation (and its use for osmotic adjustment) and efficient compartmentalisation in vacuoles, the ability of the whole plant to ensure sufficient K+ supply by maintaining high K+/Na+ discrimination, and maintenance of normal Ca2+ levels in leaves. The three salt treatments had different effects on the accumulation of ions. Findings in bi‐saline‐treated plants were of particular interest, where most of the physiological parameters studied showed partial alleviation of SO42−‐induced toxicity by Cl−. Thus, discussions on physiological responses to salinity could be further expanded in a way that more closely mimics natural salt environments.
Adult root structure of mediterranean shrubs: relationship with post‐fire regenerative syndrome
Authors: Saura‐Mas S. , Lloret F. 
Published: July 2013

AbstractLife‐history attributes can impose differences on root system structures and properties related to nutrient and water uptake. Here, we assess whether plants with different post‐fire regenerative strategies (resprouters, seeders and seeder–resprouters) differ in the topological and morphological properties of their root systems (external path, altitude, magnitude, topological index, specific root length, root length, root‐to‐shoot biomass ratio, length of the main axis of the root system and link length). To achieve these objectives, we sampled individuals from eight woody species in a shrubland located in the western Mediterranean Basin. We sampled the adult root systems using manual field excavation with the aid of an air compressor. The results indicate that resprouters have a higher root‐to‐shoot ratio, confirming their higher ability to store water, starch and nutrients and to invest in the belowground biomass. Moreover, this pattern would allow them to explore deeper parts of the soil layers. Seeder species would benefit from a higher specific root length, pointing to increased relative root growth and water uptake rates. This study confirms that seeders and resprouters may differ in nutrient and water uptake ability according to the characteristics of their root system. Species that can both resprout and establish seedlings after fire had different patterns of root system structure; in particular, root:shoot ratio was more similar to resprouters and specific root length was closer to seeders, supporting the distinct functional performance of this type of species.
Cytosolic calcium, hydrogen peroxide and related gene expression and protein modulation in Arabidopsis thaliana cell cultures respond immediately to altered gravitation: parabolic flight data
Authors: Hausmann N. , Fengler S. , Hennig A. , Franz‐Wachtel M. , Hampp R. , Neef M. 
Published: July 2013

AbstractCallus cell cultures of Arabidopsis thaliana (cv. Columbia) were exposed to parabolic flights in order to assess molecular, short‐term responses to altered gravity fields. Using transgenic cell lines, hydrogen peroxide (H2O2) and cytosolic Ca2+ were continuously monitored. In parallel, the metabolism of samples was chemically quenched (RNAlater, Ambion for RNA; acid/base for NADPH, NADP) at typical stages of a parabola [1 g before pull up; end of pull up (1.8 g), end of microgravity (20 s) and end of pull out (1.8 g)]. Cells exhibited an increase in both Ca2+ and H2O2 with the onset of microgravity, and a decline thereafter. This behaviour was accompanied by a decrease of the NADPH/NADP redox ratio, indicating Ca2+‐dependent activation of a NADPH oxidase. Microarray analyses revealed concomitant expression profiles. At the end of the microgravity phase, 396 transcripts were specifically up‐, while 485 were down‐regulated. Up‐regulation was dominated by Ca2+‐ and ROS‐related gene products. The same material was also used for analysis of phosphopeptides with 2‐D SDS PAGE. Relevant spots were identified by liquid chromatography–MS. With the exception of a chaperone (HSP 70‐3), hypergravity (1.8 g) and microgravity modified different sets of proteins. These are partly involved in primary metabolism (glycolysis, gluconeogenesis, citrate cycle) and detoxification of ROS. Taken together, these data show that both gene expression and protein modulation jointly respond within seconds to alterations in the gravity field, with a focus on metabolic adaptation, signalling and control of ROS.