bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interactions between elevated atmospheric CO2 and defoliation on North American rangeland plant species at low and high N availability
Authors: LeCain D. R. , Morgan J. A. , Hutchinson G. L. , Reeder J. D. , Dijkstra F. A. 
Published: February 2012

AbstractAlthough common disturbances of grazing lands like plant defoliation are expected to affect their sensitivity to increasing atmospheric CO2 concentration, almost no research has been conducted to evaluate how important such effects might be on the direct responses of rangelands to CO2. This growth chamber experiment subjected intact plant–soil cylinders from a Wyoming, USA, prairie to a 3‐way factorial of CO2 (370 vs. 720 μL L−1), defoliation (non‐clipped vs. clipped) and soil nitrogen (control vs. 10 g m−2 added N) under simulated natural climatic conditions. Above‐ and below‐ground biomass and N dynamics of the functional groups C3 grasses, C4 grasses and forbs were investigated. CO2 and defoliation had independent influences on biomass and N parameters of these rangeland plants. Growth under CO2‐enriched conditions enhanced above‐ground biomass 50% in C3 grasses alone, while shoot N concentration declined 16% in both C3 and C4 grasses. Plant‐soil 15N uptake was unaffected by CO2 treatment. In contrast, defoliation had no effect on biomass, but increased tissue N concentration 29% across all functional groups. Without additional N, forage quality, which is in direct relation to N concentration, will decline under increasing atmospheric CO2. Increased dominance of C3 grasses plus reduced forage quality may necessitate changes in grazing management practices in mixed‐species rangelands.
Pre‐registration dietetic students’ attitudes to learning communication skills
Authors: Power B. T. , Lennie S. C. 
Published: February 2012

How to cite this article
Power B.T. & Lennie S.C. (2012) Pre‐registration dietetic students’ attitudes to learning communication skills. J Hum Nutr Diet.25, 189–197AbstractBackground:  Communication is a core skill and a prerequisite for dietitians’ clinical competence. It is generally acknowledged that communication skills can be taught and learned. There is a paucity of published work identifying dietetic students’ attitudes towards learning communication skills, and understanding this is important.Methods:  The present cross‐sectional study aimed to address this issue using an adapted version of the Communication Skills Attitude Scale (CSAS), which was designed to capture information concerning positive and negative attitudes to learning communication skills. An online questionnaire was sent to all undergraduate and post‐graduate dietetic programmes in the UK.Results:  Of the students’ solicited for enrolment in the study, 33.4% (n = 300) completed the questionnaire. A one‐way analysis of variance showed attitudes to learning communication skills differed significantly between years of study on both subscales of the CSAS. Subsequent analyses indicated that first‐year students’ attitudes to learning communication skills were significantly more positive than those of fourth‐year students (P = 0.042). Third‐year students had significantly more positive attitudes to learning communication skills than fourth‐year students (P = 0.028). Negative attitudes were also linked to the year of study with fourth‐year students having significantly more negative attitudes than third‐year students (P = 0.046). Sex, practice placement experience and parental occupation did not significantly influence attitudes to learning communication skills.Conclusions:  These findings indicate that efforts are required to maintain positive attitudes to learning communication skills. Further longitudinal studies are recommended in this respect.
Testing metapopulation dynamics using genetic, demographic and ecological data
Authors: LAMY T. , POINTIER J. P. , JARNE P. , DAVID P. 
Published: February 2012

AbstractThe metapopulation concept is a cornerstone in the recent history of ecology and evolution. However, determining whether a natural system fits a metapopulation model is a complex issue. Extinction‐colonization dynamics are indeed often difficult to quantify because species detectability is not always 100%, resulting in an imperfect record of extinctions. Here, we explore whether combining population genetics with demographic and ecological surveys can yield more realistic estimates of metapopulation dynamics. We apply this approach to the freshwater snailDrepanotrema depressissimumin a fragmented landscape of tropical ponds. In addition to studying correlations between genetic diversity and demographical or ecological characteristics, we undertake, for the first time, a detailed search for genetic signatures of extinction–recolonization events using temporal changes in allele frequencies within sites. Surprisingly, genetic data indicate that extinction is much rarer than suggested by demographic surveys. Consequently, this system is better described as a set of populations with different sizes and immigration rates than as a true metapopulation. We identify several cases of apparent extinction owing to nondetection of low‐density populations, and of aestivating individuals in desiccated ponds. More generally, we observed a frequent mismatch between genetic and demographical/ecological information at small spatial and temporal scales. We discuss the causes of these discrepancies and show how these two types of data provide complementary information on population dynamics and history, especially when temporal genetic samples are available.
The genetic differentiation at quantitative trait loci under local adaptation
Authors: LE CORRE VALÉRIE , KREMER ANTOINE 
Published: February 2012

AbstractMost adaptive traits are controlled by large number of genes that may all together be the targets of selection. Adaptation may thus involve multiple but not necessarily substantial allele frequency changes. This has important consequences for the detection of selected loci and implies that a quantitative genetics framework may be more appropriate than the classical ‘selective sweep’ paradigm. Preferred methods to detect loci involved in local adaptation are based on the detection of ‘outlier’ values of the allelic differentiation FST. A quantitative genetics framework is adopted here to review theoretical expectations for how allelic differentiation at quantitative trait loci (FSTQ) relates to (i), neutral genetic differentiation (FST) and (ii), phenotypic differentiation (QST). We identify cases where results of outlier‐based methods are likely to be poor and where differentiation at selected loci conveys little information regarding local adaptation. A first case is when neutral differentiation is high, so that local adaptation does not necessitate increased differentiation. A second case is when local adaptation is reached via an increased covariance of allelic effects rather than via allele frequency changes, which is more likely under high gene flow when the number of loci is high and selection is recent. The comparison of theoretical predictions with observed data from the literature suggests that polygenic local adaptation involving only faint allele frequency changes are very likely in some species such as forest trees and for climate‐related traits. Recent methodological improvements that may alleviate the weakness of FST‐based detection methods are presented.
Only skin deep: shared genetic response to the deadly chytrid fungus in susceptible frog species
Authors: ROSENBLUM ERICA BREE , POORTEN THOMAS J. , SETTLES MATTHEW , MURDOCH GORDON K. 
Published: February 2012

AbstractAmphibian populations around the world are threatened by an emerging infectious pathogen, the chytrid fungus Batrachochytrium dendrobatidis (Bd). How can a fungal skin infection kill such a broad range of amphibian hosts? And do different host species have a similar response to Bd infection? Here, we use a genomics approach to understand the genetic response of multiple susceptible frog species to Bd infection. We characterize the transcriptomes of two closely related endangered frog species (Rana muscosa and Rana sierrae) and analyse whole genome expression profiles from frogs in controlled Bd infection experiments. We integrate the Rana results with a comparable data set from a more distantly related susceptible species (Silurana tropicalis). We demonstrate that Bd‐infected frogs show massive disruption of skin function and show no evidence of a robust immune response. The genetic response to infection is shared across the focal susceptible species, suggesting a common effect of Bd on susceptible frogs.
The role of immigration and in‐situ radiation in explaining blood parasite assemblages in an island bird clade
Authors: CORNUAULT JOSSELIN , BATAILLARD ANAÏS , WARREN BEN H. , LOOTVOET AMÉLIE , MIRLEAU PASCAL , DUVAL THOMAS , MILÁ BORJA , THÉBAUD CHRISTOPHE , HEEB PHILIPP 
Published: February 2012

AbstractParasite communities on islands are assembled through multiple immigrations and/or in‐situ diversification. In this study, we used a phylogenetic approach to investigate the role of such processes in shaping current patterns of diversity in Leucocytozoon, a group of haemosporidian blood parasites infecting whites eyes (Zosterops) endemic to the Mascarene archipelago (south‐western Indian Ocean). We found that this parasite community arose through a combination of multiple immigrations and in‐situ diversification, highlighting the importance of both processes in explaining island diversity. Specifically, two highly diverse parasite clades appear to have been present in the Mascarenes for most of their evolutionary history and have diversified within the archipelago, while another lineage apparently immigrated more recently, probably with human‐introduced birds. Interestingly, the evolutionary histories of one clade of parasites and Indian Ocean Zosterops seem tightly associated with a significant signal for phylogenetic congruence, suggesting that host–parasite co‐divergence may have occurred in this system.
Overlapping transport and chaperone‐binding functions within a bacterial twin‐arginine signal peptide
Authors: Grahl Sabine , Maillard Julien , Spronk Chris A. E. M. , Vuister Geerten W. , Sargent Frank 
Published: February 2012

SummaryThe twin‐arginine translocation (Tat) pathway is a protein targeting system present in many prokaryotes. The physiological role of the Tat pathway is the transmembrane translocation of fully‐folded proteins, which are targeted by N‐terminal signal peptides bearing conserved SRRxFLK ‘twin‐arginine’ amino acid motifs. In Escherichia coli the majority of Tat targeted proteins bind redox cofactors and it is important that only mature, cofactor‐loaded precursors are presented for export. Cellular processes have been unearthed that sequence these events, for example the signal peptide of the periplasmic nitrate reductase (NapA) is bound by a cytoplasmic chaperone (NapD) that is thought to regulate assembly and export of the enzyme. In this work, genetic, biophysical and structural approaches were taken to dissect the interaction between NapD and the NapA signal peptide. A NapD binding epitope was identified towards the N‐terminus of the signal peptide, which overlapped significantly with the twin‐arginine targeting motif. NMR spectroscopy revealed that the signal peptide adopted a α‐helical conformation when bound by NapD, and substitution of single residues within the NapA signal peptide was sufficient to disrupt the interaction. This work provides an increased level of understanding of signal peptide function on the bacterial Tat pathway.
The Trypanosoma brucei AIR9‐like protein is cytoskeleton‐associated and is required for nucleus positioning and accurate cleavage furrow placement
Authors: May Sophie F. , Peacock Lori , Almeida Costa Cristina I. C. , Gibson Wendy C. , Tetley Laurence , Robinson Derrick R. , Hammarton Tansy C. 
Published: February 2012

SummaryAIR9 is a cytoskeleton‐associated protein in Arabidopsis thaliana with roles in cytokinesis and cross wall maturation, and reported homologues in land plants and excavate protists, including trypanosomatids. We show that the Trypanosoma brucei AIR9‐like protein, TbAIR9, is also cytoskeleton‐associated and colocalizes with the subpellicular microtubules. We find it to be expressed in all life cycle stages and show that it is essential for normal proliferation of trypanosomes in vitro. Depletion of TbAIR9 from procyclic trypanosomes resulted in increased cell length due to increased microtubule extension at the cell posterior. Additionally, the nucleus was re‐positioned to a location posterior to the kinetoplast, leading to defects in cytokinesis and the generation of aberrant progeny. In contrast, in bloodstream trypanosomes, depletion of TbAIR9 had little effect on nucleus positioning, but resulted in aberrant cleavage furrow placement and the generation of non‐equivalent daughter cells following cytokinesis. Our data provide insight into the control of nucleus positioning in this important pathogen and emphasize differences in the cytoskeleton and cell cycle control between two life cycle stages of the T. brucei parasite.
The metabolic blueprint of Phaeodactylum tricornutum reveals a eukaryotic Entner–Doudoroff glycolytic pathway
Authors: Fabris Michele , Matthijs Michiel , Rombauts Stephane , Vyverman Wim , Goossens Alain , Baart Gino J.E. 
Published: February 2012

SummaryDiatoms are one of the most successful groups of unicellular eukaryotic algae. Successive endosymbiotic events contributed to their flexible metabolism, making them competitive in variable aquatic habitats. Although the recently sequenced genomes of the model diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana have provided the first insights into their metabolic organization, the current knowledge on diatom biochemistry remains fragmentary. By means of a genome‐wide approach, we developed DiatomCyc, a detailed pathway/genome database of P. tricornutum. DiatomCyc contains 286 pathways with 1719 metabolic reactions and 1613 assigned enzymes, spanning both the central and parts of the secondary metabolism of P. tricornutum. Central metabolic pathways, such as those of carbohydrates, amino acids and fatty acids, were covered. Furthermore, our understanding of the carbohydrate model in P. tricornutum was extended. In particular we highlight the discovery of a functional Entner–Doudoroff pathway, an ancient alternative for the glycolytic Embden–Meyerhof–Parnas pathway, and a putative phosphoketolase pathway, both uncommon in eukaryotes. DiatomCyc is accessible online (http://www.diatomcyc.org), and offers a range of software tools for the visualization and analysis of metabolic networks and ‘omics’ data. We anticipate that DiatomCyc will be key to gaining further understanding of diatom metabolism and, ultimately, will feed metabolic engineering strategies for the industrial valorization of diatoms.
Generation of an expressed sequence tag (EST) library from salt‐stressed roots of Jatropha curcas for identification of abiotic stress‐responsive genes
Authors: Eswaran N. , Parameswaran S. , Anantharaman B. , Raja Krishna Kumar G. , Sathram B. , Sudhakar Johnson T. 
Published: February 2012

AbstractImproving salinity and drought tolerance of crop plants has been an important aim of modern agricultural development, which depends on understanding the functions of genes expressed during the process of stress adaptation. EST resources are an efficient and cost‐effective solution to gene discovery. Jatropha curcas is emerging as the most promising tree oil seed as a source of biodiesel. To identify genes that respond to abiotic stress, in the present study, we report 1240 ESTs generated from root cDNA libraries of J. curcas. ESTs were clustered and assembled into a collection of 865 unigenes, with 107 contigs and 758 singleton sequences. The putative functions of several ESTs could be assigned by similarity to plant gene sequence comparisons. It was found that 23 full‐length CDS (34%) and the majority of transcription factors had sequence similarity to genes known to be involved in abiotic and biotic stress tolerance. The expression pattern of nine selected genes revealed that these genes are differentially expressed in various tissues during adaptation to stress. The data could serve as a critical resource to enable plant improvement programmes towards enhancing the adaptability of J. curcas to growth on marginal lands.
Cafestol, a coffee‐specific diterpene, induces peripheral antinociception mediated by endogenous opioid peptides
Authors: Guzzo Luciana S , Perez Andrea C , Romero Thiago RL , Azevedo Adolfo O , Duarte Igor DG 
Published: February 2012

Summary

The opioid peptides have been implicated in peripheral antinociception induced by non‐opioidergic compounds, including non‐steroidal anti‐inflammatory drugs and α2‐adrenoceptor agonists. The aims of the present study were to investigate the possible peripheral antinociceptive effect of cafestol, a diterpene present in the oil derived from coffee beans, and to evaluate the involvement of opioid peptides in its effect.
The rat paw pressure test was used to assess antinocipeptive effects. Hyperalgesia was induced by intraplantar injection of prostaglandin E2 (2 μg/paw). All drugs were locally administered into the hind‐paws of male Wistar rats.
Intraplantar injection of cafestol (20, 40 and 80 μg) induced peripheral antinociception. The antinociceptive effect of cafestol was due to a local action because the higher dose (80 μg/paw) did not produce any effect in the contralateral paw. The opioid receptor antagonist naloxone (25, 50 and 100 μg/paw) prevented the action of cafestol (80 μg/paw), whereas the aminopeptidase inhibitor bestatin (400 μg/paw) potentiated the antinociceptive effect of cafestol (40 μg/paw).
The results of the present study provide evidence that cafestol treatment has a peripheral antinociceptive effect and suggest that this effect is mediated by the release of endogenous opioids.
Ultrastructural characterization of the mesostriatal dopamine innervation in mice, including two mouse lines of conditional VGLUT2 knockout in dopamine neurons
Authors: Bérubé‐Carrière Noémie , Guay Ginette , Fortin Guillaume M. , Kullander Klas , Olson Lars , Wallén‐Mackenzie Åsa , Trudeau Louis‐Eric , Descarries Laurent 
Published: February 2012

AbstractDespite the increasing use of genetically modified mice to investigate the dopamine (DA) system, little is known about the ultrastructural features of the striatal DA innervation in the mouse. This issue is particularly relevant in view of recent evidence for expression of the vesicular glutamate transporter 2 (VGLUT2) by a subset of mesencephalic DA neurons in mouse as well as rat. We used immuno‐electron microscopy to characterize tyrosine hydroxylase (TH)‐labeled terminals in the core and shell of nucleus accumbens and the neostriatum of two mouse lines in which the Vglut2 gene was selectively disrupted in DA neurons (cKO), their control littermates, and C57BL/6/J wild‐type mice, aged P15 or adult. The three regions were also examined in cKO mice and their controls of both ages after dual TH–VGLUT2 immunolabeling. Irrespective of the region, age and genotype, the TH‐immunoreactive varicosities appeared similar in size, vesicular content, percentage with mitochondria, and exceedingly low frequency of synaptic membrane specialization. No dually labeled axon terminals were found at either age in control or in cKO mice. Unless TH and VGLUT2 are segregated in different axon terminals of the same neurons, these results favor the view that the glutamatergic cophenotype of mesencephalic DA neurons is more important during the early development of these neurons than for the establishment of their scarce synaptic connectivity. They also suggest that, in mouse even more than rat, the mesostriatal DA system operates mainly through non‐targeted release of DA, diffuse transmission and the maintenance of an ambient DA level.
Diversity and functional analysis of proteorhodopsin in marine Flavobacteria
Authors: Yoshizawa Susumu , Kawanabe Akira , Ito Hiroyasu , Kandori Hideki , Kogure Kazuhiro 
Published: February 2012

SummaryProteorhodopsin (PR) genes are widely distributed among marine prokaryotes and functions as light‐driven proton pump when expressed heterologously in Escherichia coli, suggesting that light energy passing through PR may be substantial in marine environment. However, there are no data on PR proton pump activities in native marine bacteria. Here, we demonstrate light‐driven proton pump activity (c. 124 H+ PR−1 min−1) in recently isolated marine Flavobacteria. Among 75 isolates, 38 possessed the PR gene. Illumination of cell suspensions from all eight tested strains in five genera triggered marked pH drops. The action spectrum of proton pump activity closely matched the spectral distribution of the sea surface green light field. Addition of hydroxylamine to a solubilized membrane fraction shifted the spectrum to a form characteristic of PR photobleached into retinal oxime, indicating that PRs in flavobacterial cell membranes transform the photon dose in incident radiation into energy in the form of membrane potential. Our results revealed that PR‐mediated proton transport can create the sufficient membrane potential for the ATP synthesis in native flavobacterial cells.
Sorafenib rechallenge in patients with metastatic renal cell carcinoma
Authors: Nozawa Masahiro , Yamamoto Yutaka , Minami Takafumi , Shimizu Nobutaka , Hatanaka Yuji , Tsuji Hidenori , Uemura Hirotsugu 
Published: February 2012

Study Type – Therapy (case series)Level of Evidence 4What's known on the subject? and What does the study add?Targeted agents with a similar or different target molecule are often used sequentially in the treatment of metastatic RCC. Two tyrosine kinase inhibitors, sorafenib and sunitinib, have been reported to show little cross‐resistance, when used sequentially. In addition, a recent report showed that sunitinib rechallenge could potentially benefit selected patients.This case series shows that patients once refractory to sorafenib could regain disease control on rechallenge with sorafenib during sequential treatment. Outcomes of the sorafenib rechallenge were not significantly affected by the response to the initial sorafenib treatment or by the duration of intervening treatments between first sorafenib and rechallenge.OBJECTIVE
To investigate clinical outcomes of sorafenib rechallenge during sequential therapy for patients with metastatic renal cell carcinoma (RCC).
PATIENTS AND METHODS
Patients with metastatic RCC who received sorafenib rechallenge after failed treatment first with sorafenib and subsequently with other agents, were retrospectively reviewed for patient characteristics, best response, progression‐free survival (PFS), and adverse events (AEs).
RESULTS
Of the 14 patients who received sorafenib rechallenge, 12 were evaluable for response. Eleven patients had previously undergone nephrectomy, and 10 had previously received systemic therapy, mostly interferon‐α (nine patients) and interleukin‐2 (six patients), with a median duration of 9 months.
The best responses after the first sorafenib therapy were partial response (PR) in two patients, stable disease (SD) in seven, and progressive disease (PD) in two. The median PFS was 5.7 months. Initial sorafenib therapy was discontinued because of PD in eight patients and AEs in four patients.
Rechallenge with sorafenib was undertaken after a 7.6 month median interval from the initial sorafenib challenge. Eight patients achieved SD on sorafenib rechallenge and median PFS was 5.4 (95% confidence interval, 3.8–7.0) months.
The outcome of the sorafenib rechallenge was not significantly affected by the response to the initial sorafenib treatment or by the duration of treatments received between first sorafenib and rechallenge.
No severe AE was newly observed on the rechallenge.
CONCLUSION
In the systemic treatment of advanced RCC, it was suggested that patients once refractory to sorafenib could regain disease control on rechallenge with sorafenib during sequential treatment.