106 research outputs found
Intramolecular Structural Heterogeneity altered by Long-range Contacts in an Intrinsically Disordered Protein
Short-range interactions and long-range contacts drive the 3D folding of
structured proteins. The proteins' structure has a direct impact on their
biological function. However, nearly 40% of the eukaryotes proteome is composed
of intrinsically disordered proteins (IDPs) and protein regions that fluctuate
between ensembles of numerous conformations. Therefore, to understand their
biological function, it is critical to depict how the structural ensemble
statistics correlate to the IDPs' amino acid sequence. Here, using small-angle
x-ray scattering (SAXS) and time-resolved F\"orster resonance energy transfer
(trFRET), we study the intra-molecular structural heterogeneity of the
neurofilament low intrinsically disordered tail domain (NFLt). Using
theoretical results of polymer physics, we find that the Flory scaling exponent
of NFLt sub-segments correlates linearly with their net charge, ranging from
statistics of ideal to self-avoiding chains. Surprisingly, measuring the same
segments in the context of the whole NFLt protein, we find that regardless of
the peptide sequence, the segments' structural statistics are more expanded
than when measured independently. Our findings show that while polymer physics
can, to some level, relate the IDP's sequence to its ensemble conformations,
long-range contacts between distant amino acids play a crucial role in
determining intra-molecular structures. This emphasizes the necessity of
advanced polymer theories to fully describe IDPs ensembles with the hope it
will allow us to model their biological function
Does abscisic acid affect strigolactone biosynthesis?
Strigolactones are considered a novel class of plant hormones that, in addition to their endogenous signalling function, are exuded into the rhizosphere acting as a signal to stimulate hyphal branching of arbuscular mycorrhizal (AM) fungi and germination of root parasitic plant seeds. Considering the importance of the strigolactones and their biosynthetic origin (from carotenoids), we investigated the relationship with the plant hormone abscisic acid (ABA).
Strigolactone production and ABA content in the presence of specific inhibitors of oxidative carotenoid cleavage enzymes and in several tomato ABA-deficient mutants were analysed by LC-MS/MS. In addition, the expression of two genes involved in strigolactone biosynthesis was studied.
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The carotenoid cleavage dioxygenase (CCD) inhibitor D2 reduced strigolactone but not ABA content of roots. However, in abamineSG-treated plants, an inhibitor of 9-cis-epoxycarotenoid dioxygenase (NCED), and the ABA mutants notabilis, sitiens and flacca, ABA and strigolactones were greatly reduced. The reduction in strigolactone production correlated with the downregulation of LeCCD7 and LeCCD8 genes in all three mutants.
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The results show a correlation between ABA levels and strigolactone production, and suggest a role for ABA in the regulation of strigolactone biosynthesis
A comparison of attachment representations to father and mother using the MCAST
The aim of the current study was to examine the factorial structure of the Manchester Child Attachment Story Task (MCAST), using a father doll to address the child's attachment representation to father. While the MCAST, a doll story completion task measuring attachment representations in early childhood, has been validated for use with a mother doll, its use for assessing attachment to father is relatively unexplored. Thus, an additional aim was to compare the factorial structure of the child's attachment representation to father and mother, respectively. We analyzed data from 118 first-grade children who underwent counterbalanced administration of the MCAST with a mother and father doll, respectively, within a period of three months. Exploratory factorial analysis revealed similar, three-factor solutions for attachment to father and mother, with a first factor capturing the child's (scripted) knowledge of secure base/safe haven and a second factor reflecting intrusive and conflict behavior. The third factor was different in the father and mother representations, capturing self-care and role-reversal in attachment to father and disorganization in attachment to mother. Findings support the potential usefulness of the MCAST for exploring the father-child relationship and highlight a need for further research on early attachment representations to father
Improved control and characterization of adjustable x-ray optics
We report on improvements in our efforts to control and characterize piezoelectrically adjustable, thin glass optics. In the past, an optical profilometer and a Shack-Hartmann wavefront sensor have been used to measure influence functions for a at adjustable mirror. An electronics system has since been developed to control > 100 actuator cells and has been used in a full calibration of a high-yield at adjustable mirror. The calibrated influence functions have been used to induce a pre-determined figure change to the mirror, representing our first attempt at figure control of a full mirror. Furthermore, we have adapted our metrology systems for cylindrical optics, allowing characterization of Wolter-type mirrors. We plan to use this metrology to perform the first piezoelectric figure correction of a cylindrical mirror over the next year...
Configurations of mother-child and father-child attachment as predictors of internalizing and externalizing behavioral problems: An individual participant data (IPD) meta-analysis
An unsettled question in attachment theory and research is the extent to which children's attachment patterns with mothers and fathers jointly predict developmental outcomes. In this study, we used individual participant data (IPD) meta-analysis to assess whether early attachment networks with mothers and fathers are associated with children's internalizing and externalizing behavioral problems. Following a pre-registered protocol, data from 9 studies and 1,097 children (mean age: 28.67 months) with attachment classifications to both mothers and fathers were included in analyses. We used a linear mixed effects analysis to assess differences in children's internalizing and externalizing behavioral problems as assessed via the average of both maternal and paternal reports based on whether children had two, one, or no insecure (or disorganized) attachments. Results indicated that children with an insecure attachment relationship with one or both parents were at higher risk for elevated internalizing behavioral problems compared with children who were securely attached to both parents. Children whose attachment relationships with both parents were classified as disorganized had more externalizing behavioral problems compared to children with either one or no disorganized attachment relationship with their parents. Across attachment classification networks and behavioral problems, findings suggest (a) an increased vulnerability to behavioral problems when children have insecure or disorganized attachment to both parents, and (b) that mother-child and father-child attachment relationships may not differ in the roles they play in children's development of internalizing and externalizing behavioral problems
The Glial Scar-Monocyte Interplay: A Pivotal Resolution Phase in Spinal Cord Repair
The inflammatory response in the injured spinal cord, an immune privileged site, has been mainly associated with the poor prognosis. However, recent data demonstrated that, in fact, some leukocytes, namely monocytes, are pivotal for repair due to their alternative anti-inflammatory phenotype. Given the pro-inflammatory milieu within the traumatized spinal cord, known to skew monocytes towards a classical phenotype, a pertinent question is how parenchymal-invading monocytes acquire resolving properties essential for healing, under such unfavorable conditions. In light of the spatial association between resolving (interleukin (IL)-10 producing) monocytes and the glial scar matrix chondroitin sulfate proteoglycan (CSPG), in this study we examined the mutual relationship between these two components. By inhibiting the de novo production of CSPG following spinal cord injury, we demonstrated that this extracellular matrix, mainly known for its ability to inhibit axonal growth, serves as a critical template skewing the entering monocytes towards the resolving phenotype. In vitro cell culture studies demonstrated that this matrix alone is sufficient to induce such monocyte polarization. Reciprocal conditional ablation of the monocyte-derived macrophages concentrated at the lesion margins, using diphtheria toxin, revealed that these cells have scar matrix-resolving properties. Replenishment of monocytic cell populations to the ablated mice demonstrated that this extracellular remodeling ability of the infiltrating monocytes requires their expression of the matrix-degrading enzyme, matrix metalloproteinase 13 (MMP-13), a property that was found here to be crucial for functional recovery. Altogether, this study demonstrates that the glial scar-matrix, a known obstacle to regeneration, is a critical component skewing the encountering monocytes towards a resolving phenotype. In an apparent feedback loop, monocytes were found to regulate scar resolution. This cross-regulation between the glial scar and monocytes primes the resolution of this interim phase of spinal cord repair, thereby providing a fundamental platform for the dynamic healing response
Attachment goes to court: child protection and custody issues
Attachment theory and research are drawn upon in many applied settings, including family courts, but misunderstandings are widespread and sometimes result in misapplications. The aim of this consensus statement is, therefore, to enhance understanding, counter misinformation, and steer family-court utilisation of attachment theory in a supportive, evidence-based direction, especially with regard to child protection and child custody decision-making. The article is divided into two parts. In the first, we address problems related to the use of attachment theory and research in family courts, and discuss reasons for these problems. To this end, we examine family court applications of attachment theory in the current context of the best-interest-of-the-child standard, discuss misunderstandings regarding attachment theory, and identify factors that have hindered accurate implementation. In the second part, we provide recommendations for the application of attachment theory and research. To this end, we set out three attachment principles: the child’s need for familiar, non-abusive caregivers; the value of continuity of good-enough care; and the benefits of networks of attachment relationships. We also discuss the suitability of assessments of attachment quality and caregiving behaviour to inform family court decision-making. We conclude that assessments of caregiver behaviour should take center stage. Although there is dissensus among us regarding the use of assessments of attachment quality to inform child custody and child-protection decisions, such assessments are currently most suitable for targeting and directing supportive interventions. Finally, we provide directions to guide future interdisciplinary research collaboration
Conceptual comparison of constructs as first step in data harmonization: Parental sensitivity, child temperament, and social support as illustrations
This article presents a strategy for the initial step of data harmonization in Individual Participant Data syntheses, i.e., making decisions as to which measures operationalize the constructs of interest - and which do not. This step is vital in the process of data harmonization, because a study can only be as good as its measures. If the construct validity of the measures is in question, study results are questionable as well. Our proposed strategy for data harmonization consists of three steps. First, a unitary construct is defined based on the existing literature, preferably on the theoretical framework surrounding the construct. Second, the various instruments used to measure the construct are evaluated as operationalizations of this construct, and retained or excluded based on this evaluation. Third, the scores of the included measures are recoded on the same metric. We illustrate the use of this method with three example constructs focal to the Collaboration on Attachment Transmission Synthesis (CATS) study: parental sensitivity, child temperament, and social support. This process description may aid researchers in their data pooling studies, filling a gap in the literature on the first step of data harmonization.
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Data harmonization in studies using combined datasets is of vital importance for the validity of the study results.
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We have developed and illustrated a strategy on how to define a unitary construct and evaluate whether instruments are operationalizations of this construct as the initial step in the harmonization process.
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This strategy is a transferable and reproducible method to apply to the data harmonization process
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