One-step isolation and biochemical characterization of a highlyactive plant PSII monomeric core

We describe a one-step detergent solubilization protocol for isolating a highly active form of Photosystem II (PSII) from Pisum sativum L. Detailed characterization of the preparation showed that the complex was a monomer having no light harvesting proteins attached. This core reaction centre complex had, however, a range of low molecular mass intrinsic proteins as well as the chlorophyll binding proteins CP43 and CP47 and the reaction centre proteins D1 and D2. Of particular note was the presence of a stoichiometric level of PsbW, a low molecular weight protein not present in PSII of cyanobacteria. Despite the high oxygen evolution rate, the core complex did not retain the PsbQ extrinsic protein although there was close to a full complement of PsbO and PsbR and partial level of PsbP. However, reconstitution of PsbP and PsbPQ was possible. The presence of PsbP in absence of LHCII and other chlorophyll a/b binding proteins confirms that LHCII proteins are not a strict requirement for the assembly of this extrinsic polypeptide to the PSII core in contrast with the conclusion of Caffarri et al. (2009)

The course of mental health problems in children presenting with abdominal pain in general practice

Objective. To investigate the course of mental health problems in children presenting to general practice with abdominal pain and to evaluate the extent to which abdominal pain characteristics during follow-up predict the presence of mental health problems at 12 months' follow-up. Design. A prospective cohort study with one-year follow-up. Setting. 53 general practices in the Netherlands, between May 2004 and March 2006. Subjects. 281 children aged 4-17 years. Main outcome measures. The presence of a depressive problem, an anxiety problem, and multiple non-specific somatic symptoms at follow-up and odds ratios of duration, frequency, and severity of abdominal pain with these mental health problems at follow-up. Results. A depressive problem persisted in 24/74 children (32.9%; 95% CI 22.3-44.9%), an anxiety problem in 13/43 (30.2%; 95% CI 17.2-46.1%) and the presence of multiple non-specific somatic symptoms in 75/170 children (44.1%; 95% CI 36.7-51.6%). None of the abdominal pain characteristics predicted a depressive or an anxiety problem at 12 months' follow-up. More moments of moderate to severe abdominal pain predicted the presence of multiple nonspecific somatic symptoms at follow-up. Conclusions. In one-third of the children presenting to general practice for abdominal pain, anxiety and depressive problems persist during one year of follow-up. Characteristics of the abdominal pain during the follow-up period do not predict anxiety or depressive problems after one-year follow-up. We recommend following over time children seen in primary care with abdominal pain

Validity and Reliability of the Strengths and Difficulties Questionnaire in 5–6 Year Olds: Differences by Gender or by Parental Education?

Introduction: The Strengths and Difficulties Questionnaire (SDQ) is a relatively short instrument developed to detect psychosocial problems in children aged 3-16 years. It addresses four dimensions: emotional problems, conduct problems, hyperactivity/inattention problems, peer problems that count up to the total difficulties score, and a fifth dimension; prosocial behaviour. The validity and reliability of the SDQ has not been fully investigated in younger age groups. Therefore, this study assesses the validity and reliability of the parent and teacher versions of the SDQ in children aged 5-6 years in the total sample, and in subgroups according to child gender and parental education level. Methods: The SDQ was administered as part of the Dutch regularly provided preventive health check for children aged 5-6 years. Parents provided information on 4750 children and teachers on 4516 children. Results: Factor analyses of the parent and teacher SDQ confirmed that the original five scales were present (parent RMSEA = 0.05; teacher RMSEA = 0.07). Interrater correlations between parents and teachers were small (ICCs of 0.21-0.44) but comparable to what is generally found for psychosocial problem assessments in children. These correlations were larger for males than for females. Cronbach's alphas for the total difficulties score were 0.77 for the parent SDQ and 0.81 for the teacher SDQ. Four of the subscales on the parent SDQ and two of the subscales on the teacher SDQ had an alpha <0.70. Alphas were generally higher for male children and for low parental education level. Discussion: The validity and reliability of the total difficulties score of the parent and teacher SDQ are satisfactory in all groups by informant, child gender, and parental education level. Our results support the use of the SDQ in younger age groups. However, some subscales are less reliable and we recommend only to use the total difficulties score for screening purposes

External quality assessment of the molecular diagnostics and genotyping of meticillin-resistant Staphylococcus aureus

Two multicentre external quality assessments (EQA) for the molecular detection and genotyping of meticillin-resistant Staphylococcus aureus (MRSA) were arranged. Firstly, 11 samples containing various amounts of inactivated MRSA strains, meticillin-susceptible S. aureus (MSSA), meticillin-resistant coagulase-negative staphylococci (MRCoNS) or Escherichia coli were distributed to 82 laboratories. Samples containing 102 or 103 MRSA cells were correctly scored in only 16 and 46% of the datasets returned, respectively. Two of the used MSSA strains contained an SCCmec cassette lacking the mecA gene. There was a marked difference in the percentage of correct results for these two MSSA strains (37 and 39%) compared to the MSSA strain lacking the SCCmec cassette (88%). Secondly, a panel for MRSA genotyping, consisting of ten samples (two identical, three genetically related and five unique strains) was distributed to 19 laboratories. Seventy-three percent of the datasets recorded all samples correctly. Most pulsed-field gel electrophoresis (PFGE) protocols proved to be suboptimal, resulting in inferior resolution in the higher or lower fragment regions. The performance of molecular diagnostics for MRSA shows no significant changes since our first EQA in 2006. The first molecular typing results are encouraging. Both assessments indicate that programme expansion is required and that major performance discrepancies continue to exist

Genetic analyses of maternal and teacher ratings on attention problems in 7-year-old Dutch twins

The goal of the present study is to examine genetic and environmental influences on maternal and teacher ratings of Attention Problems (AP) in 7-year-old children. Teachers completed the Teacher Report Form (N=2259 pairs), and mothers the Child Behavior Checklist (N=2057 pairs). Higher correlations were found in twins rated by the same teacher than in twins rated by different teachers. This can be explained by rater bias or by a greater environmental sharing in twins, who are in the same classroom. We further found that 41% of the variation in maternal and teacher ratings is explained by a common factor. The heritability of this common factor is 78%. The heritabilities of the rater specific factors of mothers and teachers are 76% and 39%, respectively. Because Attention Problems that are persistent over situations may indicate more serious behavior problems than context dependent Attention Problems, we believe that gene finding strategies should focus on this common phenotype

Combining Shapley value and statistics to the analysis of gene expression data in children exposed to air pollution

<p>Abstract</p> <p>Background</p> <p>In gene expression analysis, statistical tests for differential gene expression provide lists of candidate genes having, individually, a sufficiently low <it>p</it>-value. However, the interpretation of each single <it>p</it>-value within complex systems involving several interacting genes is problematic. In parallel, in the last sixty years, <it>game theory </it>has been applied to political and social problems to assess the power of interacting agents in forcing a decision and, more recently, to represent the relevance of genes in response to certain conditions.</p> <p>Results</p> <p>In this paper we introduce a Bootstrap procedure to test the null hypothesis that each gene has the same relevance between two conditions, where the relevance is represented by the Shapley value of a particular coalitional game defined on a microarray data-set. This method, which is called <it>Comparative Analysis of Shapley value </it>(shortly, CASh), is applied to data concerning the gene expression in children differentially exposed to air pollution. The results provided by CASh are compared with the results from a parametric statistical test for testing differential gene expression. Both lists of genes provided by CASh and t-test are informative enough to discriminate exposed subjects on the basis of their gene expression profiles. While many genes are selected in common by CASh and the parametric test, it turns out that the biological interpretation of the differences between these two selections is more interesting, suggesting a different interpretation of the main biological pathways in gene expression regulation for exposed individuals. A simulation study suggests that CASh offers more power than t-test for the detection of differential gene expression variability.</p> <p>Conclusion</p> <p>CASh is successfully applied to gene expression analysis of a data-set where the joint expression behavior of genes may be critical to characterize the expression response to air pollution. We demonstrate a synergistic effect between coalitional games and statistics that resulted in a selection of genes with a potential impact in the regulation of complex pathways.</p

Local Adaptation of Aboveground Herbivores towards Plant Phenotypes Induced by Soil Biota

Background: Soil biota may trigger strong physiological responses in plants and consequently induce distinct phenotypes. Plant phenotype, in turn, has a strong impact on herbivore performance. Here, we tested the hypothesis that aboveground herbivores are able to adapt to plant phenotypes induced by soil biota. Methodology and Principal Findings: We bred spider mites for 15 generations on snap beans with three different belowground biotic interactions: (i) no biota (to serve as control), (ii) arbuscular mycorrhizal fungi and (ii) root-feeding nematodes. Subsequently, we conducted a reciprocal selection experiment using these spider mites, which had been kept on the differently treated plants. Belowground treatments induced changes in plant biomass, nutrient composition and water content. No direct chemical defence through cyanogenesis was detected in any of the plant groups. Growth rates of spider mites were higher on the ecotypes on which they were bred for 15 generations, although the statistical significance disappeared for mites from the nematode treatment when corrected for all multiple comparisons. Conclusion/Significance: These results demonstrate that belowground biota may indeed impose selection on the aboveground insect herbivores mediated by the host plant. The observed adaptation was driven by variable quantitativ

Azimuthal anisotropy and correlations at large transverse momenta in p+pp+p and Au+Au collisions at sNN\sqrt{s_{_{NN}}}= 200 GeV

Results on high transverse momentum charged particle emission with respect to the reaction plane are presented for Au+Au collisions at $\sqrt{s_{_{NN}}}$= 200 GeV. Two- and four-particle correlations results are presented as well as a comparison of azimuthal correlations in Au+Au collisions to those in $p+p$ at the same energy. Elliptic anisotropy, $v_2$, is found to reach its maximum at $p_t \sim 3$ GeV/c, then decrease slowly and remain significant up to $p_t\approx 7$ -- 10 GeV/c. Stronger suppression is found in the back-to-back high-$p_t$ particle correlations for particles emitted out-of-plane compared to those emitted in-plane. The centrality dependence of $v_2$ at intermediate $p_t$ is compared to simple models based on jet quenching.Comment: 4 figures. Published version as PRL 93, 252301 (2004