bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spore heat resistance plays an important role in disturbance‐mediated assemblage shift of ectomycorrhizal fungi colonizing Pinus muricata seedlings
Authors: Peay Kabir G. , Garbelotto Matteo , Bruns Thomas D. 
Published: March 2009

Summary

Abiotic disturbance plays an important role in determining assemblage structure and maintaining species richness in many ecosystems. Disturbances events are complex, often affecting multiple environmental parameters simultaneously and causing selective removal of biomass. For this reason, observational studies often fail to elucidate the primary mechanism by which disturbance modifies assembly structure. This is particularly true of microbial systems where reduction in biomass or removal of competitive dominants is not visually obvious.
Fire is a major disturbance in pinaceous forests, which are characterized by ectomycorrhizal fungal root associations. To determine the specific mechanisms through which this disturbance affects ectomycorrhizal communities, we experimentally simulated the effects of fire by growing seedlings in field soil exposed to factorial combinations of soil heating and ash addition. Ectomycorrhizal colonists in each of the treatments were then identified from seedling roots using DNA sequences.
Both soil heating and ash addition caused changes to the soil chemical environment and altered the fungal assemblages found on seedling roots. The effect on the ectomycorrhizal assembly was most pronounced from soil heating, which caused an overall simplification and increasing dominance by a few taxa with ruderal life‐history strategies.
We also conducted a follow‐up experiment to see whether selective mortality of ectomycorrhizal spores might contribute to these patterns. Heat exposure had strong negative effects on all species tested. However, spore heat tolerance was highest for the species that showed the greatest increase in abundance on seedlings grown in heated soils.
Synthesis. Fire alters below‐ground communities through changes in soil chemistry and mortality of resident organisms. Our results show that soil heating and selective mortality are key mechanisms determining post‐fire assemblage structure of ectomycorrhizal fungi. These disturbances favour competitively inferior species and may help maintain diversity of ectomycorrhizal assemblages at the landscape scale.
Pleistocene glaciation events shape genetic structure across the range of the American lobster, Homarus americanus
Authors: KENCHINGTON ELLEN L. , HARDING GARETH C. , JONES MATHEW W. , PRODÖHL PAULO A. 
Published: March 2009

AbstractA north/south discontinuity along the northeastern coast of North America in the genetic structure of the American lobster (Homarus americanus) was detected using a suite of 13 microsatellite loci assessed using spatial analyses. Population genetic data laid over existing data on physiographic changes and sea‐surface temperatures were used to reconstruct the Pleistocene distribution of this species. A postglacial northern‐edge colonization model best explains the relative genetic homogeneity of the northern region compared to the southern region centred in the Gulf of Maine. Population genetic analyses identified significant structure (range of standardized theta 0–0.02) but no significant evidence for isolation by distance. The novel application of spatial genetic analyses to a marine species allowed us to interpret these results by providing a greater insight into the evolutionary factors responsible for shaping the genetic structure of this species throughout is natural range.
HlyU acts as an H‐NS antirepressor in the regulation of the RTX toxin gene essential for the virulence of the human pathogen Vibrio vulnificus CMCP6
Authors: Liu Moqing , Naka Hiroaki , Crosa Jorge H. 
Published: March 2009

SummaryIn Vibrio vulnificus, HlyU upregulates the expression of the large RTX toxin gene. In this work we identified the binding site of HlyU to −417 to −376 bp of the rtxA1 operon transcription start site. lacZ fusions for a series of progressive deletions from the rtxA1 operon promoter showed that transcriptional activity increased independently of HlyU when its binding site was absent. Thus HlyU must regulate the rtxA1 operon expression by antagonizing a negative regulator. Concomitantly we found that an hns mutant resulted in an increase in the expression of the rtxA1 operon genes. Multiple copies of HlyU can increase the promoter activity only in the presence of H‐NS underscoring the hypothesis that HlyU must alleviate the repression by this protein. H‐NS binds to a region that extends upstream and downstream of the rtxA1 operon promoter. In the upstream region it binds to five AT‐rich sites of which two overlap the HlyU binding site. Competitive footprinting and gel shift data demonstrate HlyU's higher affinity as compared with H‐NS resulting in the de‐repression and a corresponding increased expression of the rtxA1 operon.
ClpS is the recognition component for Escherichia coli substrates of the N‐end rule degradation pathway
Authors: Schmidt Ronny , Zahn Regina , Bukau Bernd , Mogk Axel 
Published: March 2009

SummaryThe N‐end rule degradation pathway states that the half‐life of a protein is determined by the nature of its N‐terminal residue. In Escherichia coli the adaptor protein ClpS directly interacts with destabilizing N‐terminal residues and transfers them to the ClpA/ClpP proteolytic complex for degradation. The crucial role of ClpS in N‐end rule degradation is currently under debate, since ClpA/ClpP was shown to process selected N‐terminal degrons harbouring destabilizing residues in the absence of ClpS. Here, we investigated the contribution of ClpS to N‐end rule degradation by two approaches. First, we performed a systematic mutagenesis of selected N‐degron model substrates, demonstrating that ClpS but not ClpA specifically senses the nature of N‐terminal residues. Second, we identified two natural N‐end rule substrates of E. coli: Dps and PATase (YgjG). The in vivo degradation of both proteins strictly relied on ClpS, thereby establishing the function of ClpS as the essential discriminator of the E. coli N‐end rule pathway.
The evolution of senescence through decelerating selection for system reliability
Authors: LAIRD R. A. , SHERRATT T. N. 
Published: March 2009

AbstractSenescence is a universal phenomenon in organisms, characterized by increasing mortality and decreasing fecundity with advancing chronological age. Most proximate agents of senescence, such as reactive oxygen species and UV radiation, are thought to operate by causing a gradual build‐up of bodily damage. Yet most current evolutionary theories of senescence emphasize the deleterious effects of functioning genes in late life, leaving a gap between proximate and ultimate explanations. Here, we present an evolutionary model of senescence based on reliability theory, in which beneficial genes or gene products gradually get damaged and thereby fail, rather than actively cause harm. Specifically, the model allows organisms to evolve multiple redundant copies of a gene product (or gene) that performs a vital function, assuming that organisms can avoid condition‐dependent death so long as at least one copy remains undamaged. We show that organisms with low levels of extrinsic mortality, and high levels of genetic damage, tend to evolve high levels of redundancy, and that mutation–selection balance results in a stable population distribution of the number of redundant elements. In contrast to previous evolutionary models of senescence, the mortality curves that emerge from such populations match empirical senescence patterns in three key respects: they exhibit: (1) an initially low, but rapidly increasing mortality rate at young ages, (2) a plateau in mortality at advanced ages and (3) ‘mortality compensation’, whereby the height of the mortality plateau is independent of the environmental conditions under which different populations evolved.
The timing of food‐deceptive flowers: a commentary on Internicola et al. (2008)
Authors: Ruxton G. D. , Martin SchaEfer H. 
Published: March 2009

AbstractA recent article presents a study of pollinator visitation behaviour that is used to evaluate the selective pressure that pollinator visitation rate might have on the timing of the production of nonrewarding flowers. Here we take issue with the conclusions of the paper that there should be selection pressure for nonrewarding flowers to be available earlier in the season in order to avoid dissimilar sympatric rewarding species. Consideration of selection pressure must take into account temporal variation in total pollinator availability, pollinator longevity and unlearned response, and the stability of plant communities over time, as well as the learned responses of individual pollinators that the original study focused on. Learning alone would not necessarily select for early flowering by nonrewarders if temporal variation in pollinator numbers is strong or naïve pollinators consistently appear throughout the flowering season. Further, we argue that early flowering could simply be a natural corollary of longevity of flowers needed to combat negative frequency‐dependent selection and low overall visitation rates by pollinators, rather than a trait that has been specifically selected to reduce temporal overlap with competing rewarding species.
Set‐up and routine use of a database of 10 555 genotyped blood donors to facilitate the screening of compatible blood components for alloimmunized patients
Authors: Perreault J. , Lavoie J. , Painchaud P. , Côté M. , Constanzo‐Yanez J. , Côté R. , Delage G. , Gendron F. , Dubuc S. , Caron B. , Lemieux R. , St‐Louis M. 
Published: March 2009

Background and Objectives  Large‐scale genotyping of blood donors for red blood cell and platelet antigens has been predicted to replace phenotyping assays in the screening of compatible blood components for alloimmunized patients. Although several genotyping platforms have been described, novel procedures and processes are needed to perform genotyping efficiently and to maximize its benefits for blood banks.Materials and Methods  Here we describe the processes and procedures developed to introduce large‐scale genotyping in our routine operations.Results  Preliminary cost–benefit analysis indicated that genotyping must target frequent blood donors (> 3 donations/year) to be efficiently used. A custom‐designed computer application was developed to manage the whole project. It selects frequent donors among recent donations, prints coded labels to identify blood samples sent to the external genotyping laboratory, and stores genotyping results. It can search for donors compatible for any combination of the 22 genotyped antigens as well as consult the current inventory for the presence of the corresponding blood components. The phenotype of recovered components is confirmed by standard serology techniques prior to shipment to hospitals.Conclusion  Since October 2007, 10 555 blood donors have been genotyped. The database is used on a regular basis to find compatible blood components with a genotype–phenotype concordance of 99·6%.
Handling Stress as a Measurement of Personality in Great Tit Nestlings (Parus major)
Authors: Fucikova Eva , Drent Piet J. , Smits Nadine , Van Oers Kees 
Published: March 2009

AbstractInterest in personality is growing in a wide range of disciplines, but only in a few systems it is possible to assess the survival value of personality. Field studies looking at the relationship between personality and survival value early in life are greatly hampered by the fact that personality can at present only be assessed after individuals become independent from their parents. In passerines, for example, this is often after a period of intensive selection for the survival on fledglings. The main aim of this study is therefore to develop a method to measure personality before this period of selection. For this purpose, we developed the handling stress (HS) test. We measured HS in 14‐d‐old great tit nestlings by counting the number of breast movements (breath rate) in four subsequent 15‐s bouts for 1 min; before and after they were socially isolated from their siblings for 15 min. To calculate the repeatability of HS, we repeated the test 6 mo later. To assess the relationship between HS and exploratory behaviour, we correlated the outcome of both tests. We ran tests both on birds of lines selected for extreme personality and on wild birds from a natural population. We found that birds selected for fast exploration reacted more to HS compared with birds selected for slow exploration and that HS was repeatable in different life phases. We confirmed this by finding an increase in the HS with increasing exploratory scores in wild birds. These results show that we can use the HS test as a measurement of personality, making it a potential tool for studying the relationship between personality and survival value early in life.
The Economic Impacts of a New Dam in South‐East Queensland
Authors: Wittwer Glyn 
Published: March 2009

Abstract South‐East Queensland has combined the most rapid population growth in Australia with rainfall that has persisted below average for many years. The Queensland Government has responded with a number of plans to supplement existing water supplies in the region. This paper uses a multiregional, dynamic CGE model to estimate the regional impacts of construction of Traveston dam. The magnitude of net welfare benefits of the project depends on underlying assumptions concerning future rainfall patterns. All the mainland state governments are proposing water supply augmentation measures. It is probable that a number of these projects are not justifiable on economic grounds.
‘A Tolerable Figure’: William III, the General Election of November–December 1701 and the Appointment of the Fourth Earl of Manchester as Secretary of State in January 1702
Authors: PRICE RICHARD 
Published: March 2009

AbstractDuring the final weeks of his life, William III summoned a new parliament and, encouraged by the outcome of the election, began to put together a new government for the purpose of renewing his struggle against Louis XIV of France. The first appointments made by the king, who died before he could complete all the changes, have often been regarded as inferior choices, men brought into office on a temporary basis until politicians of greater weight could be employed. This article shows that any such conclusion fails to do justice to at least one of the new ministers of January 1702, the fourth earl of Manchester, whose correspondence as an ambassador in the 1690s indicates qualities and experience more than sufficient to justify his appointment as secretary of state.
Precarious Work and Economic Migration: Emerging Immigrant Divisions of Labour in Greater London's Service Sector
Authors: MCDOWELL LINDA , BATNITZKY ADINA , DYER SARAH 
Published: March 2009

AbstractThe aim of this article is to assess the connections between the continued expansion of forms of insecure work and the impact of rising numbers of economic migrants employed in UK labour markets. It shows how competition between foreign‐born workers for jobs in the UK is currently being recast by changes in the jobs available, in forms of precarious labour market attachment and by new patterns of migration into the UK since EU expansion in 2004. The article documents the ways in which migrants with different sets of social characteristics (nationality, gender and skin colour) and different sets of legal entitlements (legal citizenship, EU membership and entitlement to residence) are differentially placed in their competition for some of the poorest jobs in the British economy, drawing on an empirical study of the migrant divisions of labour emerging in two significant sectors in the service industries. It concludes by arguing that new and deeper divisions are emerging between foreign‐born workers in the UK.Résumé Cet article vise àévaluer les rapports entre l'essor constant de formes de travail précaire et l'impact des migrants économiques en nombre croissant employés sur les marchés du travail britanniques. La concurrence entre les travailleurs d'origine étrangère pour des emplois au Royaume‐Uni subit actuellement une mutation du fait de l'évolution des postes disponibles, sous des formes d'intégration précaire au marché du travail et selon de nouveaux modèles d'immigration depuis l'élargissement de l'UE en 2004. À partir d'une étude empirique sur les divisions du travail qui se dessinent chez les migrants dans deux importants secteurs de l'industrie des services, l'article met en évidence les manières dont les migrants réunissant différentes caractéristiques sociales (nationalité, genre et couleur de peau) et différentes habilitations légales (citoyenneté, ressortissant de l'UE et droit de séjour) se placent différemment dans la compétition pour certains des postes les plus médiocres de l'économie britannique. Il apparaît en conclusion que des divisions nouvelles et plus profondes apparaissent entre les travailleurs d'origine étrangère au Royaume‐Uni.
The final destiny of acantholytic cells in pemphigus is Fas mediated
Authors: Pacheco‐Tovar MG , Avalos‐Díaz E , Vega‐Memije E , Bollain‐y‐Goytia JJ , López‐Robles E , Hojyo‐Tomoka MT , Domínguez‐Soto L , Herrera‐Esparza R 
Published: March 2009

AbstractBackground  Pemphigus is an autoimmune disease characterized by the formation of intra‐epidermal blisters. Patients develop auto‐antibodies against desmoglein 1 and 3 proteins and induce acantholysis.Objective  This work addresses the issue of whether the Fas pathway mediates acantholysis. Furthermore, the possible suppliers of the Fas pathway were investigated.Methods  Seventeen biopsies of pemphigus patients were studied by haematoxylin and eosin staining, and apoptosis was defined by TUNEL. The expression of Fas, FasL and caspase 3 was studied by in situ hybridization and immunohistochemistry. Cell infiltrates were studied by immunofluorescence with monoclonal anti‐CD3, CD4, CD8, CD19 and CD69.Results  All of the biopsies showed intra‐epidermal blisters, acantholytic cells and inflammatory infiltrates. The blisters expressed Fas, FasL and caspase 3. Cell infiltrates were composed of CD8 and a few CD4+CD69+ cells. Additionally, CD19+ cells were detected. Interestingly, the Fas expression was increased in acantholytic cells and perilesional keratinocytes. Incidentally, these cells exhibited apoptotic features. Interestingly, the CD8 cells expressed FasL.Conclusion  This paper presents the morphological evidence that apoptosis and acantholysis are linked. Therefore, the Fas pathway is associated with CD8 cells in pemphigus lesions.Conflicts of interestNone declared.
Efficacy and safety of long‐term mycophenolate sodium therapy in pemphigus vulgaris
Authors: Baskan E Bulbul , Yilmaz M , Tunali S , Saricaoglu H 
Published: March 2009

AbstractBackground  Pemphigus is a chronic immunobullous disease, characterized by formation of blisters and erosions in skin and/or mucous membranes. This severe disease requires systemic immunosuppressive therapy. However, some patients are refractory, and long‐term use of immunosuppressive agents can cause serious side‐effects. Mycophenolic acid is increasingly being used as a corticosteroid‐sparing agent or as monotherapy in immunosuppressive regimens.Objectives  We aimed to evaluate the effectiveness of mycophenolate sodium, a sodium salt of mycophenolic acid, in the treatment of pemphigus vulgaris.Methods  Six patients who were diagnosed as pemphigus vulgaris with active, refractory disease were treated with mycophenolate sodium. Three patients received mycophenolate sodium monotherapy; three patients received mycophenolate in combination with steroid. All patients were monitored regularly.Results  Mycophenolate sodium was well tolerated with a similar efficacy of mycophenolate mofetil, and no side‐effects have been observed.Conclusions  Mycophenolate sodium appears to be an effective and safe alternative in the treatment of pemphigus vulgaris.
Inert gas rebreathing: the effect of haemoglobin based pulmonary shunt flow correction on the accuracy of cardiac output measurements in clinical practice
Authors: Trinkmann F. , Papavassiliu T. , Kraus F. , Leweling H. , Schoenberg Stefan O. , Borggrefe M. , Kaden J. J. , Saur J. 
Published: March 2009

SummaryBackground:  Cardiac output (CO) is an important cardiac parameter, however its determination is difficult in clinical routine. Non‐invasive inert gas rebreathing (IGR) measurements yielded promising results in recent studies. It directly measures pulmonary blood flow (PBF) which equals CO in absence of significant pulmonary shunt flow (QS). A reliable shunt correction requiring the haemoglobin concentration (cHb) as only value to be entered manually has been implemented. Therefore, the aim of the study was to evaluate the effect of various approaches to QS correction on the accuracy of IGR.Methods:  Cardiac output determined by cardiac magnetic resonance imaging (CMR) served as reference values. The data was analysed in four groups: PBF without correcting for QS (group A), shunt correction using the patients’ individual cHb values (group B), a fixed standard cHb of 14·0 g dl−1 (group C) and a gender‐adapted standard cHb for male (15·0 g dl−1) and female (13·5 g dl−1) probands each (group D).Results:  147 patients were analysed. Mean COCMR was 5·2 ± 1·4 l min−1, mean COIGR was 4·8 ± 1·3 l min−1 in group A, 5·1 ± 1·3 in group B, 5·1 ± 1·3 l min−1 in group C and 5·1 ± 1·4 l min−1 in group D. The accuracy in group A (mean bias 0·5 ± 1·1 l min−1) was significantly lower as compared to groups B, C and D (0·1 ± 1·1 l min−1; P<0·01).Conclusion:  IGR allows a reliable non‐invasive determination of CO. Since PBF significantly increased the measurement bias, shunt correction should always be applied. A fixed cHb of 14·0 g dl−1 can be used for both genders if the exact cHb value is not known. Nevertheless, the individual value should be used if any possible.
Factors Associated with Increasing Nursing Home Closures
Authors: Castle Nicholas G. , Engberg John , Lave Judith , Fisher Andrew 
Published: March 2009

Purpose. We determine the rate of nursing home closures for 7 years (1999–2005) and examine internal (e.g., quality), organizational (e.g., chain membership), and external (e.g., competition) factors associated with these closures.Design and Method. The names of the closed facilities and dates of closure from state regulators in all 50 states were obtained. This information was linked to the Online Survey, Certification, and Reporting data, which contains information on internal, organizational, and market factors for almost all nursing homes in the United States.Results. One thousand seven hundred and eighty‐nine facilities closed over this time period (1999–2005). The average annual rate of closure was about 2 percent of facilities, but the rate of closure was found to be increasing. Nursing homes with higher rates of deficiency citations, hospital‐based facilities, chain members, small bed size, and facilities located in markets with high levels of competition were more likely to close. High Medicaid occupancy rates were associated with a high likelihood of closure, especially for facilities with low Medicaid reimbursement rates.Implications. As states actively debate about how to redistribute long‐term care services/dollars, our findings show that they should be cognizant of the potential these decisions have for facilitating nursing home closures.