This study examined the role of childhood abuse and neglect in sensitizing adolescents to the effects of proximal stressful life events in a cross-sectional sample of 103 depressed and nondepressed adolescents. Consistent with hypotheses, adolescents with a history of childhood abuse and/or neglect reported a lower level of threat of stressful life events prior to episode onset than that reported by those without. This effect was specific to those on their 1st episode of depression and was specific to independent events (i.e., stressors outside of adolescents' control). Further, this effect was robust when controlling for level of chronic difficulties, which was higher in those with childhood abuse and/or neglect. The authors suggest that childhood abuse and/or neglect may be an important risk factor that sensitizes individuals to the effects of acute independent life events.

This study examined the combined and cumulative effects of supportive-positive and harsh-negative parenting behaviors on children's depressive symptoms. A diverse sample of 515 male and female elementary and middle school students (ages 7 to 11) and their parents provided reports of the children's depressive symptoms. Parents provided self-reports of supportive-positive and harsh-negative parenting behaviors. Structural equation modeling indicated that supportive-positive and harsh-negative parenting behaviors were nearly orthogonal dimensions of parenting and both related to children's depressive symptoms. Supportive-positive parenting behaviors did not moderate the relation between harsh-negative parenting behaviors and children's depressive symptoms. Results have implications for family intervention and prevention strategies.

In a sample of 299 children (grades 2, 4, and 6), we examined parenting and negative life events as predictors of depressive cognitions, specifically low self-perceived competence, depressive cognitive schemas, and depressogenic attributional style. We also examined developmental trends in these relations. Children completed measures of parenting, negative life events, and depressive cognitions. Parents also completed measures of parenting and negative life events. Consistent with our hypotheses, negative parenting and negative life events corresponded with higher levels of depressive cognitions, whereas positive parenting corresponded with lower levels of depressive cognitions. The relations between negative parenting and negative automatic thoughts were stronger for older children. Theoretical and practical implications are discussed.

BackgroundThe effect that traditional and modern DNA extraction methods have on applications to study the role of gut microbiota in health and disease is a topic of current interest. Genomic DNA was extracted from three faecal samples and one probiotic capsule using three popular methods; chaotropic (CHAO) method, phenol/chloroform (PHEC) extraction, proprietary kit (QIAG). The performance of each of these methods on DNA yield and quality, microbiota composition using quantitative PCR, deep sequencing of the 16S rRNA gene, and sequencing analysis pipeline was evaluated.ResultsThe CHAO yielded the highest and the QIAG kit the lowest amount of double-stranded DNA, but the purity of isolated nucleic acids was better for the latter method. The CHAO method yielded a higher concentration of bacterial taxa per mass (g) of faeces. Sequencing coverage was higher in CHAO method but a higher proportion of the initial sequencing reads were retained for assignments to operational taxonomic unit (OTU) in the QIAG kit compared to the other methods. The QIAG kit appeared to have longer trimmed reads and shorter regions of worse quality than the other two methods. A distinct separation of α-diversity indices between different DNA extraction methods was not observed. When compositional dissimilarities between samples were explored, a strong separation was observed according to sample type. The effect of the extraction method was either marginal (Bray–Curtis distance) or none (unweighted Unifrac distance). Taxon membership and abundance in each sample was independent of the DNA extraction method used.ConclusionsWe have benchmarked several DNA extraction methods commonly used in gut microbiota research and their differences depended on the downstream applications intended for use. Caution should be paid when the intention is to pool and analyse samples or data from studies which have used different DNA extraction methods.Electronic supplementary materialThe online version of this article (doi:10.1186/s13104-016-2171-7) contains supplementary material, which is available to authorized users.