Spatial attention shifting and phonological processing in adults with dyslexia

According to Hari and Renvall’s (2001) sluggish attentional shifting (SAS) hypothesis people with dyslexia have a central deficit in attention shifting. Here we assessed whether a group of adults with dyslexia showed impaired performance on shifting visual spatial attention. Twelve adults with dyslexia and 12 control adult participants took part in a Posner style focused attention orientation task and a shift attention orientation task. The participants also completed standardized measures of single word reading, spelling, IQ, phonological processing, speed of processing and non-word reading. Overall, the dyslexic participants showed the same pattern of performance as the control participants on the attention-orienting task, but completed the tasks at a consistently slower pace. Specifically, participants in both groups found short target presentation intervals more difficult than longer target presentation intervals, and participants in both groups were more impaired when cue-to-target information was invalid 20% of the time (shift task) than when it was valid all of the time (focused task). However, the group with dyslexia was significantly more impaired across the board

Brief report: the relationship between writing transcription skills and writing measures differs between children who self-report being monolingual or bilingual

This study explored how the skills involved in writing were associated with written language measures in children who self-reported being bilingual or monolingual. Twenty children were matched for age and gender and took part in a writing task and a series of tasks to measure writing transcription skills. The results found that there was no difference in the writing measures for either group. There was a different pattern of significant associations between the transcription skills and the writing measures for the two groups. The results are discussed in terms of the different ways in which a complex task like writing can be accomplished successfully

Delay or deficit? Spelling processes in children with specific language impairment

Few studies have explored the phonological, morphological and orthographic spellings skills of children with specific language impairment (SLI) simultaneously. Fifteen children with SLI (mean age = 113.07 months, SD = 8.61) completed language and spelling tasks alongside chronological-age controls and spelling-age controls. While the children with SLI showed a deficit in phonological spelling, they performed comparably to spelling-age controls on morphological spelling skills, and there were no differences between the three groups in producing orthographically legal spellings. The results also highlighted the potential importance of adequate non-word repetition skills in relation to effective spelling skills, and demonstrated that not all children with spoken language impairments show marked spelling difficulties. Findings are discussed in relation to theory, educational assessment and practice

Development of a Body Dissatisfaction Scale assessment tool

The present research details the development of a new pictorial scale (Body Dissatisfaction Scale) to be used in the measurement of body dissatisfaction. The scale comprises nine female and nine male images of computer generated bodies that increase successively in body weight. Using a sample of 190 students female = 130, male = 60) results showed that the new scale exhibits good validity, with participants being able to correctly identify body weight differences between all bodies in the scale. Evidence for construct validity was demonstrated by significant correlations between ratings of perceived actual body size using the current scale and participants' BMI. Body dissatisfaction measured using the current scale was also negatively correlated with a measure of body appreciation. Test-retest reliability remained stable over a 5 week period. The scale improves on previous pictorial scales by offering both male and female versions while offering improved realism and consistency between images

The effects of planning and handwriting style on quantity measures in secondary school children's writing

The study aimed to evaluate the proposer, translator, editor, and transcriber process model of writing in the context of secondary school children. Eighty-three children completed written texts under conditions that facilitated the proposer and placed resource demands on the transcriber. It was found that the number of words, lexical richness, and the number of sentences were affected by transcription resource demands, while the number of sentences was increased when the proposer was facilitated. There were also by-gender interactions that indicated male writers and female writers completed the tasks to different product levels. The discussion proposes that future developments of the model take into account a more direct interaction between the transcriber and translation level processes when considering this age group

Postglacial expansion of the arctic keystone copepod calanus glacialis

Calanus glacialis, a major contributor to zooplankton biomass in the Arctic shelf seas, is a key link between primary production and higher trophic levels that may be sensitive to climate warming. The aim of this study was to explore genetic variation in contemporary populations of this species to infer possible changes during the Quaternary period, and to assess its population structure in both space and time. Calanus glacialis was sampled in the fjords of Spitsbergen (Hornsund and Kongsfjorden) in 2003, 2004, 2006, 2009 and 2012. The sequence of a mitochondrial marker, belonging to the ND5 gene, selected for the study was 1249 base pairs long and distinguished 75 unique haplotypes among 140 individuals that formed three main clades. There was no detectable pattern in the distribution of haplotypes by geographic distance or over time. Interestingly, a Bayesian skyline plot suggested that a 1000-fold increase in population size occurred approximately 10,000 years before present, suggesting a species expansion after the Last Glacial Maximum.GAME from the National Science Centre, the Polish Ministry of Science and Higher Education Iuventus Plus [IP2014 050573]; FCT-PT [CCMAR/Multi/04326/2013]; [2011/03/B/NZ8/02876

Selective Inhibition of Type III Secretion Activated Signaling by the Salmonella Effector AvrA

Salmonella enterica utilizes a type III secretion system (TTSS) encoded in its pathogenicity island 1 to mediate its initial interactions with intestinal epithelial cells, which are characterized by the stimulation of actin cytoskeleton reorganization and a profound reprogramming of gene expression. These responses result from the stimulation of Rho-family GTPases and downstream signaling pathways by specific effector proteins delivered by this TTSS. We show here that AvrA, an effector protein of this TTSS, specifically inhibits the Salmonella-induced activation of the JNK pathway through its interaction with MKK7, although it does not interfere with the bacterial infection-induced NF-κB activation. We also show that AvrA is phosphorylated at evolutionary conserved residues by a TTSS-effector-activated ERK pathway. This interplay between effector proteins delivered by the same TTSS highlights the remarkable complexity of these systems

PIWI Associated siRNAs and piRNAs Specifically Require the Caenorhabditis elegans HEN1 Ortholog henn-1

Small RNAs—including piRNAs, miRNAs, and endogenous siRNAs—bind Argonaute proteins to form RNA silencing complexes that target coding genes, transposons, and aberrant RNAs. To assess the requirements for endogenous siRNA formation and activity in Caenorhabditis elegans, we developed a GFP-based sensor for the endogenous siRNA 22G siR-1, one of a set of abundant siRNAs processed from a precursor RNA mapping to the X chromosome, the X-cluster. Silencing of the sensor is also dependent on the partially complementary, unlinked 26G siR-O7 siRNA. We show that 26G siR-O7 acts in trans to initiate 22G siRNA formation from the X-cluster. The presence of several mispairs between 26G siR-O7 and the X-cluster mRNA, as well as mutagenesis of the siRNA sensor, indicates that siRNA target recognition is permissive to a degree of mispairing. From a candidate reverse genetic screen, we identified several factors required for 22G siR-1 activity, including the chromatin factors mes-4 and gfl-1, the Argonaute ergo-1, and the 3′ methyltransferase henn-1. Quantitative RT–PCR of small RNAs in a henn-1 mutant and deep sequencing of methylated small RNAs indicate that siRNAs and piRNAs that associate with PIWI clade Argonautes are methylated by HENN-1, while siRNAs and miRNAs that associate with non-PIWI clade Argonautes are not. Thus, PIWI-class Argonaute proteins are specifically adapted to associate with methylated small RNAs in C. elegans

The complete mitochondrial genome of the citrus red mite Panonychus citri (Acari: Tetranychidae): high genome rearrangement and extremely truncated tRNAs

<p>Abstract</p> <p>Background</p> <p>The family Tetranychidae (Chelicerata: Acari) includes ~1200 species, many of which are of agronomic importance. To date, mitochondrial genomes of only two Tetranychidae species have been sequenced, and it has been found that these two mitochondrial genomes are characterized by many unusual features in genome organization and structure such as gene order and nucleotide frequency. The scarcity of available sequence data has greatly impeded evolutionary studies in Acari (mites and ticks). Information on Tetranychidae mitochondrial genomes is quite important for phylogenetic evaluation and population genetics, as well as the molecular evolution of functional genes such as acaricide-resistance genes. In this study, we sequenced the complete mitochondrial genome of <it>Panonychus citri </it>(Family Tetranychidae), a worldwide citrus pest, and provide a comparison to other Acari.</p> <p>Results</p> <p>The mitochondrial genome of <it>P. citri </it>is a typical circular molecule of 13,077 bp, and contains the complete set of 37 genes that are usually found in metazoans. This is the smallest mitochondrial genome within all sequenced Acari and other Chelicerata, primarily due to the significant size reduction of protein coding genes (PCGs), a large rRNA gene, and the A + T-rich region. The mitochondrial gene order for <it>P. citri </it>is the same as those for <it>P. ulmi </it>and <it>Tetranychus urticae</it>, but distinctly different from other Acari by a series of gene translocations and/or inversions. The majority of the <it>P. citri </it>mitochondrial genome has a high A + T content (85.28%), which is also reflected by AT-rich codons being used more frequently, but exhibits a positive GC-skew (0.03). The Acari mitochondrial <it>nad1 </it>exhibits a faster amino acid substitution rate than other genes, and the variation of nucleotide substitution patterns of PCGs is significantly correlated with the G + C content. Most tRNA genes of <it>P. citri </it>are extremely truncated and atypical (44-65, 54.1 ± 4.1 bp), lacking either the T- or D-arm, as found in <it>P. ulmi</it>, <it>T. urticae</it>, and other Acariform mites.</p> <p>Conclusions</p> <p>The <it>P. citri </it>mitochondrial gene order is markedly different from those of other chelicerates, but is conserved within the family Tetranychidae indicating that high rearrangements have occurred after Tetranychidae diverged from other Acari. Comparative analyses suggest that the genome size, gene order, gene content, codon usage, and base composition are strongly variable among Acari mitochondrial genomes. While extremely small and unusual tRNA genes seem to be common for Acariform mites, further experimental evidence is needed.</p

Structural and Functional Insights into the Pilotin-Secretin Complex of the Type II Secretion System

Gram-negative bacteria secrete virulence factors and assemble fibre structures on their cell surface using specialized secretion systems. Three of these, T2SS, T3SS and T4PS, are characterized by large outer membrane channels formed by proteins called secretins. Usually, a cognate lipoprotein pilot is essential for the assembly of the secretin in the outer membrane. The structures of the pilotins of the T3SS and T4PS have been described. However in the T2SS, the molecular mechanism of this process is poorly understood and its structural basis is unknown. Here we report the crystal structure of the pilotin of the T2SS that comprises an arrangement of four α-helices profoundly different from previously solved pilotins from the T3SS and T4P and known four α-helix bundles. The architecture can be described as the insertion of one α-helical hairpin into a second open α-helical hairpin with bent final helix. NMR, CD and fluorescence spectroscopy show that the pilotin binds tightly to 18 residues close to the C-terminus of the secretin. These residues, unstructured before binding to the pilotin, become helical on binding. Data collected from crystals of the complex suggests how the secretin peptide binds to the pilotin and further experiments confirm the importance of these C-terminal residues in vivo