bluuebunny/crossref_metadata_2025_split huggingface dataset:
Educational technology – mapping the terrain with Bernstein as cartographer
Authors: Czerniewicz L. 
Published: August 2010

AbstractThis paper uses the literature of educational technology as the site of analysis in order to map the field of educational technology. Having considered Kuhn and Bourdieu's theories, the paper frames the analysis of the field in Bernsteinian terms as a horizontal knowledge structure in a vertical knowledge discourse. Using the concepts of interacting discursive planes, the paper maps the field in terms of its general approach planes and its problem planes. Finally, the paper shows that researchers in the field themselves acknowledge its weak grammar, and calls for commensurability of approaches to be acknowledged in order for robust knowledge to be developed and the legitimacy of the field to be enhanced.
Factorial structure of the perception of risk factors for type 2 diabetes scale: exploratory and confirmatory factor analyses
Authors: Sousa Valmi D. , Ryan‐Wenger Nancy A. , Driessnack Martha , Jaber Ala'a F. 
Published: August 2010

AbstractRationale, aims and objectives  The extent to which individuals' perceptions of risk for type 2 diabetes are related to their actual risks and health‐promoting behaviours is not well known. Yet perception of risk for type 2 diabetes may influence the likelihood that individual would engage in preventive behaviours. The purpose of this study was to evaluate the psychometric properties of the perception of risk factors for type 2 diabetes (PRF‐T2DM).Methods  A descriptive, correlational, methodological design was used to conduct this study. The sample consisted of 629 adults from 42 states of the United States. A demographic questionnaire, the PRF‐T2DM, the health‐promoting lifestyle profile II and the depressive cognition scale were used to collect the data. Data analyses consisted of descriptive statistics, scale and item analyses, Pearson's correlation analysis, and exploratory and confirmatory factor analyses.Results  The PRF‐T2DM has a Cronbach's alpha of 0.81. Both extracted factors had Cronbach's alphas of 0.74 and 0.80, respectively. Most inter‐item and item‐to‐total correlation coefficients for factor 1 and factor 2 met the recommended criteria of r = 0.30 to r = 0.70. The PRF‐T2DM achieved all minimum recommended criteria for model fit (χ2/d.f. = 2.33, goodness of fit index = 0.95, adjusted goodness of fit index = 0.93, comparative fit index = 0.94, root mean square error of approximation = 0.05, root mean residual = 0.05 and the P value for test of close fit = 0.33).Conclusions  All statistical estimates and measures of model fit were above the standard recommended criteria. The scale has potential uses in research and clinical practice. Further development and psychometric evaluation of the PRF‐T2DM is warranted.
Multiple morbidity is associated with increased problems of food access in hospital: a cross‐sectional survey utilising the Cumulative Illness Rating Scale
Authors: Naithani S. , Whelan K. , Thomas J. E. , Gulliford M. C. 
Published: August 2010

AbstractBackground:  Problems of undernutrition are common in hospital in‐patients. Multiple morbidity increases with age and may contribute to nutritional risks. This research aimed to determine whether increased burden of long‐term conditions is associated with patients’ difficulties gaining access to food in hospital.Methods:  A survey was implemented in 29 wards at four hospitals using a questionnaire measure of patients’ experiences of food access and the Cumulative Illness Rating Scale (CIRS) to evaluate the burden of long‐term illness in each patient. Experiences of food access were evaluated in relation to CIRS score category using random effects logistic regression to adjust for age group, sex and clustering by ward.Results:  Data were analysed for 764/1154 (66%) eligible participants, including 384 women. The median age was 60 years (range 18–96 years). CIRS scores were analysed using the categories 0 (104 patients), 1–3 (197), 4–6 (285), 7–9 (144) and ≥10 (34). When the CIRS was zero, 10% of patients experienced physical problems with food access, whereas, when the CIRS was ≥10, 41% experienced physical barriers to food access, adjusted odds ratio 3.65 (1.14–11.7, P = 0.029). Problems with food quality were experienced by 13% with CIRS = 0 and 32% with CIRS ≥ 10 (adjusted odds ratio 3.97, 1.35–11.6, P = 0.012). Participants with greater morbidity were more likely to report that depression, breathing difficulties or chewing and swallowing difficulties affected the amount of food that they ate at mealtimes.Conclusions:  Patients with multiple morbidities are more vulnerable to experiencing physical barriers to accessing food and increased concerns with food quality. Assessing barriers to food access is particularly important in multiple morbidity.
Employment impact and financial burden for families of children with fragile X syndrome: findings from the National Fragile X Survey
Authors: Ouyang L. , Grosse S. , Raspa M. , Bailey D. 
Published: August 2010

AbstractBackground  The employment impact and financial burden experienced by families of children with fragile X syndrome (FXS) has not been quantified in the USA.Method  Using a national fragile X family survey, we analysed data on 1019 families with at least one child who had a full FXS mutation. Out‐of‐pocket expenditures related to fragile X were reported. We used logistic regression to examine the role of insurance, number of affected children, and number of total co‐occurring conditions in predicting the financial burden and employment impact of FXS, while adjusting for race, education, marital status and other sociodemographic predictors.Results  Almost half of families affected by FXS reported that they had experienced an increased financial burden and nearly 60% stated that they had had to change work hours or stop work because of FXS. Families with health insurance that met family needs were significantly less likely to report an excess financial burden. The type of insurance (private or public) was not associated with the reported financial burden. Affected children's mutation status, especially male children with the full mutation, was associated with employment impact. The total number of co‐occurring conditions was associated with both financial burden and employment impact.Conclusions  Families affected by FXS experienced a significant employment impact and financial burden. Policies designed to help families with FXS need to take into consideration the dimension of co‐occurring conditions.
Role of Escherichia coli YbeY, a highly conserved protein, in rRNA processing
Authors: Davies Bryan W. , Köhrer Caroline , Jacob Asha I. , Simmons Lyle A. , Zhu Jianyu , Aleman Lourdes M. , RajBhandary Uttam L. , Walker Graham C. 
Published: August 2010

SummaryThe UPF0054 protein family is highly conserved with homologues present in nearly every sequenced bacterium. In some bacteria, the respective gene is essential, while in others its loss results in a highly pleiotropic phenotype. Despite detailed structural studies, a cellular role for this protein family has remained unknown. We report here that deletion of the Escherichia coli homologue, YbeY, causes striking defects that affect ribosome activity, translational fidelity and ribosome assembly. Mapping of 16S, 23S and 5S rRNA termini reveals that YbeY influences the maturation of all three rRNAs, with a particularly strong effect on maturation at both the 5′‐ and 3′‐ends of 16S rRNA as well as maturation of the 5′‐termini of 23S and 5S rRNAs. Furthermore, we demonstrate strong genetic interactions between ybeY and rnc (encoding RNase III), ybeY and rnr (encoding RNase R), and ybeY and pnp (encoding PNPase), further suggesting a role for YbeY in rRNA maturation. Mutation of highly conserved amino acids in YbeY, allowed the identification of two residues (H114, R59) that were found to have a significant effect in vivo. We discuss the implications of these findings for rRNA maturation and ribosome assembly in bacteria.
Identification and characterization of two families of F420H2‐dependent reductases from Mycobacteria that catalyse aflatoxin degradation
Authors: Taylor Matthew C. , Jackson Colin J. , Tattersall David B. , French Nigel , Peat Thomas S. , Newman Janet , Briggs Lyndall J. , Lapalikar Gauri V. , Campbell Peter M. , Scott Colin , Russell Robyn J. , Oakeshott John G. 
Published: August 2010

SummaryAflatoxins are polyaromatic mycotoxins that contaminate a range of food crops as a result of fungal growth and contribute to serious health problems in the developing world because of their toxicity and mutagenicity. Although relatively resistant to biotic degradation, aflatoxins can be metabolized by certain species of Actinomycetales. However, the enzymatic basis for their breakdown has not been reported until now. We have identified nine Mycobacterium smegmatis enzymes that utilize the deazaflavin cofactor F420H2 to catalyse the reduction of the α,β‐unsaturated ester moiety of aflatoxins, activating the molecules for spontaneous hydrolysis and detoxification. These enzymes belong to two previously uncharacterized F420H2 dependent reductase (FDR‐A and ‐B) families that are distantly related to the flavin mononucleotide (FMN) dependent pyridoxamine 5′‐phosphate oxidases (PNPOxs). We have solved crystal structures of an enzyme from each FDR family and show that they, like the PNPOxs, adopt a split barrel protein fold, although the FDRs also possess an extended and highly charged F420H2 binding groove. A general role for these enzymes in xenobiotic metabolism is discussed, including the observation that the nitro‐reductase Rv3547 from Mycobacterium tuberculosis that is responsible for the activation of bicyclic nitroimidazole prodrugs belongs to the FDR‐A family.
The phage shock protein PspA facilitates divalent metal transport and is required for virulence of Salmonella enterica sv. Typhimurium
Authors: Karlinsey Joyce E. , Maguire Michael E. , Becker Lynne A. , Crouch Marie‐Laure V. , Fang Ferric C. 
Published: August 2010

SummaryThe phage shock protein (Psp) system is induced by extracytoplasmic stress and thought to be important for the maintenance of proton motive force. We investigated the contribution of PspA to Salmonella virulence. A pspA deletion mutation significantly attenuates the virulence of Salmonella enterica serovar Typhimurium following intraperitoneal inoculation of C3H/HeN (Ityr) mice. PspA was found to be specifically required for virulence in mice expressing the natural resistance‐associated macrophage protein 1 (Nramp1) (Slc11a1) divalent metal transporter, which restricts microbial growth by limiting the availability of essential divalent metals within the phagosome. Salmonella competes with Nramp1 by expressing multiple metal uptake systems including the Nramp‐homologue MntH, the ABC transporter SitABCD and the ZIP family transporter ZupT. PspA was found to facilitate Mn2+ transport by MntH and SitABCD, as well as Zn2+ and Mn2+ transport by ZupT. In vitro uptake of 54Mn2+ by MntH and ZupT was reduced in the absence of PspA. Transport‐deficient mutants exhibit reduced viability in the absence of PspA when grown under metal‐limited conditions. Moreover, the ZupT transporter is required for Salmonella enterica serovar Typhimurium virulence in Nramp1‐expressing mice. We propose that PspA promotes Salmonella virulence by maintaining proton motive force, which is required for the function of multiple transporters mediating bacterial divalent metal acquisition during infection.
Integrating conjugative elements of the SXT/R391 family trigger the excision and drive the mobilization of a new class of Vibrio genomic islands
Authors: Daccord Aurélie , Ceccarelli Daniela , Burrus Vincent 
Published: August 2010

SummaryIn vibrios and enterobacteria lateral gene transfer is often facilitated by integrating conjugative elements (ICEs) of the SXT/R391 family. SXT/R391 ICEs integrate by site‐specific recombination into prfC and transfer by conjugation, a process that is initiated at a specific locus called the origin of transfer (oriTSXT). We identified genomic islands (GIs) harbouring a sequence that shares > 63% identity with oriTSXT in three species of Vibrio. Unlike SXT/R391 ICEs, these GIs are integrated into a gene coding for a putative stress‐induced protein and do not appear to carry any gene coding for a conjugative machinery or for mobilization proteins. Our results show that SXT/R391 ICEs trigger the excision and mediate the conjugative transfer in trans of the three Vibrio GIs at high frequency. GIs' excision is independent of the ICE‐encoded recombinase and is controlled by the ICE‐encoded transcriptional activator SetCD, which is expressed during the host SOS response. Both mobI and traI, two ICE‐borne genes involved in oriT recognition, are essential for GIs' transfer. We also found that SXT/R391 ICEs mobilize in trans over 1 Mb of chromosomal DNA located 5′ of the GIs' integration site. Together these results support a novel mechanism of mobilization of GIs by ICEs of the SXT/R391 family.
Chloroquine susceptibility and reversibility in a Plasmodium falciparum genetic cross
Authors: Patel Jigar J. , Thacker Drew , Tan John C. , Pleeter Perri , Checkley Lisa , Gonzales Joseph M. , Deng Bingbing , Roepe Paul D. , Cooper Roland A. , Ferdig Michael T. 
Published: August 2010

SummaryMutations in the Plasmodium falciparum chloroquine (CQ) resistance transporter (PfCRT) are major determinants of verapamil (VP)‐reversible CQ resistance (CQR). In the presence of mutant PfCRT, additional genes contribute to the wide range of CQ susceptibilities observed. It is not known if these genes influence mechanisms of chemosensitization by CQR reversal agents. Using quantitative trait locus (QTL) mapping of progeny clones from the HB3 × Dd2 cross, we show that the P. falciparum multidrug resistance gene 1 (pfmdr1) interacts with the South‐East Asia‐derived mutant pfcrt haplotype to modulate CQR levels. A novel chromosome 7 locus is predicted to contribute with the pfcrt and pfmdr1 loci to influence CQR levels. Chemoreversal via a wide range of chemical structures operates through a direct pfcrt‐based mechanism. Direct inhibition of parasite growth by these reversal agents is influenced by pfcrt mutations and additional loci. Direct labelling of purified recombinant PfMDR1 protein with a highly specific photoaffinity CQ analogue, and lack of competition for photolabelling by VP, supports our QTL predictions. We find no evidence that pfmdr1 copy number affects CQ response in the progeny; however, inheritance patterns indicate that an allele‐specific interaction between pfmdr1 and pfcrt is part of the complex genetic background of CQR.
Vitronectin in bacterial pathogenesis: a host protein used in complement escape and cellular invasion
Authors: Singh Birendra , Su Yu‐Ching , Riesbeck Kristian 
Published: August 2010

SummaryThe multifunctional human glycoprotein vitronectin (Vn) plays a significant role in cell migration, tissue repair and regulation of membrane attack complex (MAC) formation. It also promotes neutrophil infiltration and, thus, enhances the inflammatory process during infection. In the host, a balanced homeostasis is maintained by Vn due to neutralization of the self‐reactivity of the MAC. On the other hand, Vn bound to the bacterial surface protects from MAC‐mediated lysis and enhances adhesion. Gram‐negative bacterial pathogens including Moraxella catarrhalis, Haemophilus influenzae and Neisseria gonorrhoeae use Vn recruitment to prevent MAC deposition at their surface. Moreover, Gram‐positive bacterial pathogens such as Streptococcus pneumoniae and S. pyogenes utilize Vn for effective adhesion to host cells and subsequent internalization. Vitronectin has an Arg–Gly–Asp (RGD) sequence for binding the host cell integrin receptors and a separate bacterial‐binding domain for pathogens, and thus more likely functions to cross‐link bacteria and epithelial cells. Once bacteria are attached to the vitronectin–integrin complex, various host cell‐signalling events are activated and promote internalization. In this review, we focus on the important roles of vitronectin in bacterial pathogenesis and describe different strategies used by pathogens to evade the host response by the help of this intriguing molecule.
The bifunctional abiotic stress signalling regulator and endogenous RNA silencing suppressor FIERY1 is required for lateral root formation
Authors: CHEN HAO , XIONG LIMING 
Published: August 2010

ABSTRACTThe Arabidopsis FIERY1 (FRY1) locus was originally identified as a negative regulator of stress‐responsive gene expression and later shown to be required for suppression of RNA silencing. In this study we discovered that the FRY1 locus also regulates lateral root formation. Compared with the wild type, fry1 mutant seedlings generated significantly fewer lateral roots under normal growth conditions and also exhibited a dramatically reduced sensitivity to auxin in inducing lateral root initiation. Using transgenic plants that overexpress a yeast homolog of FRY1 that possesses only the 3′, 5′‐bisphosphate nucleotidase activity but not the inositol 1‐phosphatase activity, we demonstrated that the lateral root phenotypes in fry1 result from loss of the nucleotidase activity. Furthermore, a T‐DNA insertion mutant of another RNA silencing suppressor, XRN4 (but not XRN2 or XRN3), which is an exoribonuclease that is inhibited by the substrate of the FRY1 3′, 5′‐bisphosphate nucleotidase, exhibits similar lateral root defects. Although fry1 and xrn4 exhibited reduced sensitivity to ethylene, our experiments demonstrated that restoration of ethylene sensitivity in the fry1 mutant is not sufficient to rescue the lateral root phenotypes of fry1. Our results indicate that RNA silencing modulated by FRY1 and XRN4 plays an important role in shaping root architecture.
The transcription factor SlAREB1 confers drought, salt stress tolerance and regulates biotic and abiotic stress‐related genes in tomato
Authors: ORELLANA SANDRA , YAÑEZ MÓNICA , ESPINOZA ANALÍA , VERDUGO ISABEL , GONZÁLEZ ENRIQUE , RUIZ‐LARA SIMÓN , CASARETTO JOSÉ A. 
Published: August 2010

ABSTRACTMembers of the abscisic acid‐responsive element binding protein (AREB)/abscisic acid‐responsive element binding factor (ABF) subfamily of basic leucine zipper (bZIP) transcription factors have been implicated in abscisic acid (ABA) and abiotic stress responses in plants. Here we describe two members identified in cultivated tomato (Solanum lycopersicum), named SlAREB1 and SlAREB2. Expression of SlAREB1 and SlAREB2 is induced by drought and salinity in both leaves and root tissues, although that of SlAREB1 was more affected. In stress assays, SlAREB1‐overexpressing transgenic tomato plants showed increased tolerance to salt and water stress compared to wild‐type and SlAREB1‐down‐regulating transgenic plants, as assessed by physiological parameters such as relative water content (RWC), chlorophyll fluorescence and damage by lipoperoxidation. In order to identify SlAREB1 target genes responsible for the enhanced tolerance, microarray and cDNA‐amplified fragment length polymorphism (AFLP) analyses were performed. Genes encoding oxidative stress‐related proteins, lipid transfer proteins (LTPs), transcription regulators and late embryogenesis abundant proteins were found among the up‐regulated genes in SlAREB1‐overexpressing lines, especially in aerial tissue. Notably, several genes encoding defence proteins associated with responses to biotic stress (e.g. pathogenesis‐related proteins, protease inhibitors, and catabolic enzymes) were also up‐regulated by SlAREB1 overexpression, suggesting that this bZIP transcription factor is involved in ABA signals that participate in abiotic stress and possibly in response to pathogens.
Fusarium graminearum as a dry rot pathogen of potato in the USA: prevalence, comparison of host isolate aggressiveness and factors affecting aetiology
Authors: Estrada Jr R. , Gudmestad N. C. , Rivera V. V. , Secor G. A. 
Published: August 2010

A 2004–2005 survey of potatoes from stores in the north‐central potato‐producing region of the USA showed that the predominant causes of dry rot were Fusarium graminearum and Fusarium sambucinum. Isolates of F. graminearum originally isolated from potato tubers with dry rot (n = 15), wheat kernels with scab (n = 15), and sugarbeet tap roots with decay (n = 5) were tested for aggressiveness to potato tubers. There were no significant differences in aggressiveness among isolates of F. graminearum, regardless of original host, as measured by their ability to cause dry rot. These findings may have implications for survival of F. graminearum inoculum since potatoes, wheat and sugarbeets are frequently used in crop rotation in the region. Fusarium graminearum required larger wounds for infection of potato tubers than F. sambucinum. Plug‐removal injury, simulating a stolon‐removal injury, resulted in equal incidence of dry rot caused by the two Fusarium species, whereas abrasion and bruising injury were sufficient for infection and dry rot development by F. sambucinum, but not F. graminearum. A change in harvest practices from vine‐killing prior to harvest to mechanical vine‐killing on the day of harvest may be a factor affecting the onset of dry rot caused by F. graminearum, since this process often causes large wounds at the stem end of the tubers when the stolon is forcibly removed.
Aggressiveness of eight Venturia inaequalis isolates virulent or avirulent to the major resistance gene Rvi6 on a non‐Rvi6 apple cultivar
Authors: Caffier V. , Didelot F. , Pumo B. , Causeur D. , Durel C. E. , Parisi L. 
Published: August 2010

For sustainable management of scab‐resistant apple cultivars, it is necessary to understand the role of aggressiveness in the adaptation of Venturia inaequalis populations and particularly the costs to the organism of acquiring additional virulence. The aims of the present study were (i) to identify the quantitative variables that are most important in determining the differences in aggressiveness among groups of V. inaequalis isolates, and (ii) to ascertain whether virulent and avirulent isolates of V. inaequalis differ significantly in aggressiveness. The aggressiveness of eight isolates that differed in their virulence to the major resistance gene Rvi6 was compared on the non‐Rvi6 apple cv. Gala. Three components of aggressiveness, namely lesion density, the number of spores per square centimetre of leaf area, and the number of spores per lesion, were evaluated 21 days after inoculation, and the kinetics of lesion density over time were analysed in terms of maximum lesion density, length of latent period and rate of lesion appearance. On the second youngest but fully developed leaf at the time of inoculation, maximum lesion density in the virulent group was 20% lower and the latent period 7% longer, than in the avirulent group. However, the alternative hypothesis, namely that isolates had adapted to quantitative resistance present in cv. Gala depending on their cultivar of origin, could not be rejected. The analysis of the kinetics of lesion density by a non‐linear mixed‐effect model proved useful in the assessment of aggressiveness.