A new child-friendly 3D bimanual protocol to assess upper limb movement in children with unilateral cerebral palsy: Development and validation

Unilateral cerebral palsy (uCP) causes upper limb movement disorders that impact on daily activities, especially in bimanual condition. However, a few studies have proposed bimanual tasks for 3D motion analysis. The aim of this study was to validate the new version of a child-friendly, 3D, bimanual protocol for the measurement of joint angles and movement quality variables. Twenty children with uCP and 20 typically developing children (TDC) performed the five-task protocol integrated into a game scenario. Each task specifically targeted one or two upper limb degrees of freedom. Joint angles, smoothness and trajectory straightness were calculated. Elbow extension, supination, wrist extension and adduction amplitudes were reduced; hand trajectories were less smooth and straight in children with uCP compared to TDC. Correlations between the performance-based score and kinematic variables were strong. High within and between-session reliability was found for most joint angle variables and lower reliability was found for smoothness and straightness in most tasks. The results therefore demonstrated the validity and reliability of the new protocol for the objective assessment of bimanual function in children with uCP. The evaluation of both joint angles and movement quality variables should increase understanding of pathological movement patterns and help clinicians to optimize treatment.ClinicalTrials.gov identifier: NCT03888443.     

Standardizing Immunohistochemistry: A New Reference Control for Detecting Staining Problems

A new standardized immunohistochemistry (IHC) control for breast cancer testing comprises formalin-fixed human epidermal growth factor receptor 2, estrogen receptor, or progesterone receptor peptide antigens covalently attached to 8-µm glass beads. The antigen-coated beads are suspended in a liquid matrix that hardens upon pipetting onto a glass microscope slide. The antigen-coated beads remain in place through deparaffinization, antigen retrieval, and immunostaining. The intensity of the beads’ stain provides feedback regarding the efficacy of both antigen retrieval and immunostaining. As a first report, we tested the sensitivity and specificity of the new IHC controls (“IHControls”). To evaluate sensitivity, various staining problems were simulated. IHControls detected primary and secondary reagent degradation similarly to tissue controls. This first group of IHControls behaved similarly to tissue controls expressing high concentrations of the antigen. The IHControls were also able to detect aberrations in antigen retrieval, as simulated by sub-optimal times or temperatures. Specificity testing revealed that each antigen-coated bead was specific for its cognate IHC test antibody. The data support the conclusion that, like tissue controls, IHControls are capable of verifying the analytic components of an immunohistochemical stain. Unlike tissue controls, IHControls are prepared in large bulk lots, fostering day-to-day reproducibility that can be standardized across laboratories.     

The cellular pathway of photosynthate transfer in the developing wheat grain. II. A structural analysis and histochemical studies of the pathway from the crease phloem to the endosperm cavity

In the developing wheat grain, photosynthate is transferred longitudinally along the crease phloem and then laterally into the endosperm cavity through the crease vascular parenchyma, pigment strand and nucellar projection. In order to clarify this cellular pathway of photosynthate unloading, and hence the controlling mechanism of grain filling, the potential for symplastic and apoplastic transfer was examined through structural and histochemical studies on these tissue types. It was found that cells in the crease region from the phloem to the nucellar projection are interconnected by numerous plasmodesmata and have dense cytoplasm with abundant mitochondria. Histochemical studies confirmed that, at the stage of grain development studied, an apoplastic barrier exists in the cell walls of the pigment strand. This barrier is composed of lignin, phenolics and suberin. The potential capacity for symplastic transfer, determined by measuring plasmodesmatal frequencies and computing potential sucrose fluxes through these plasmodesmata, indicated that there is sufficient plasmodesmatal cross-sectional area to support symplastic unloading of photosynthate at the rate required for normal grain growth. The potential capacity for membrane transport of sucrose to the apoplast was assessed by measuring plasma membrane surface areas of the various cell types and computing potential plasma membrane fluxes of sucrose. These fluxes indicated that the combined plasma membrane surface areas of the sieve element–companion cell (se–cc) complexes, vascular parenchyma and pigment strand are not sufficient to allow sucrose transfer to the apoplast at the observed rates. In contrast, the wall ingrowths of the transfer cells in the nucellar projection amplify the membrane surface area up to 22-fold, supporting the observed rates of sucrose transfer into the endosperm cavity. We conclude that photosynthate moves via the symplast from the se–cc complexes to the nucellar projection transfer cells, from where it is transferred across the plasma membrane into the endosperm cavity. The apoplastic barrier in the pigment strand is considered to restrict solute movement to the symplast and block apoplastic solute exchange between maternal and embryonic tissues. The implications of this cellular pathway in relation to the control of photosynthate transfer in the developing grain are discussed.     

Characterizing and predicting species distributions across environments and scales: Argentine ant occurrences in the eye of the beholder

Aim Species distribution models (SDMs) or, more specifically, ecological niche models (ENMs) are a useful and rapidly proliferating tool in ecology and global change biology. ENMs attempt to capture associations between a species and its environment and are often used to draw biological inferences, to predict potential occurrences in unoccupied regions and to forecast future distributions under environmental change. The accuracy of ENMs, however, hinges critically on the quality of occurrence data. ENMs often use haphazardly collected data rather than data collected across the full spectrum of existing environmental conditions. Moreover, it remains unclear how processes affecting ENM predictions operate at different spatial scales. The scale (i.e. grain size) of analysis may be dictated more by the sampling regime than by biologically meaningful processes. The aim of our study is to jointly quantify how issues relating to region and scale affect ENM predictions using an economically important and ecologically damaging invasive species, the Argentine ant (Linepithema humile). Location California, USA. Methods We analysed the relationship between sampling sufficiency, regional differences in environmental parameter space and cell size of analysis and resampling environmental layers using two independently collected sets of presence/absence data. Differences in variable importance were determined using model averaging and logistic regression. Model accuracy was measured with area under the curve (AUC) and Cohen's kappa. Results We first demonstrate that insufficient sampling of environmental parameter space can cause large errors in predicted distributions and biological interpretation. Models performed best when they were parametrized with data that sufficiently sampled environmental parameter space. Second, we show that altering the spatial grain of analysis changes the relative importance of different environmental variables. These changes apparently result from how environmental constraints and the sampling distributions of environmental variables change with spatial grain. Conclusions These findings have clear relevance for biological inference. Taken together, our results illustrate potentially general limitations for ENMs, especially when such models are used to predict species occurrences in novel environments. We offer basic methodological and conceptual guidelines for appropriate sampling and scale matching.     

Influence of derived operation-specific tractor emission data on results from an LCI on wheat production

The shortage of data for emissions from agricultural tractors contributes to LCA results on environmental load from modern crop production possibly having high error levels and high uncertainties. The first part of this work describes measurements and calculations made in order to obtain operation-specific agricultural emission data. Calculations are based on emission data measured on a standard 70 kW tractor of a widely available make. In the second part, results from an LCI on wheat production based on traditionally used emission data are calculated and compared with results obtained when using the emission data for specific working operations derived in part one. One conclusion of the study is that the emission values, when related to the energy in the used fuel, show very large variations between different driving operations. Another conclusion is that the use of the new data results in a marked reduction of the total air emissions produced in the wheat production chain, especially for CO and HC, but also for NO_x and SO₂.     

Interaction between the light quality and flowering time pathways in Arabidopsis

Flowering in Arabidopsis is accelerated by a reduced ratio of red light to far-red light (R/FR), which indicates the proximity of competitive vegetation. By exploiting the natural genetic variation in flowering time responses to low R/FR, we obtained further insight into the complex pathways that fine-tune the transition to flowering in Arabidopsis. The Bla-6 ecotype does not flower significantly earlier in response to low R/FR, but is still able to display other features of shade avoidance, suggesting branching of low R/FR signalling. Here we show that the muted flowering response of Bla-6 is due to high levels of the floral repressor FLOWERING LOCUS C (FLC), conferred by a combination of functional FLC and FRIGIDA ( FRI ) alleles with a 'weak' FY allele. The Bla-6 FY allele encodes a protein with a corrupted WW binding domain, and we provide evidence that this locus plays a key role in the natural variation in light quality-induced flowering in Arabidopsis. In Bla-6, FLC blocks promotion to flowering by reduced R/FR by inhibiting expression of the floral integrator FLOWERING LOCUS T ( FT ) in a dose-dependent manner. Reduction of FLC removes this obstruction, and Bla6 plants then exhibit strong induction of FT and flower early in response to a low R/FR signal. This paper illustrates the intricate interaction of environmental signals and genetic factors to regulate flowering in Arabidopsis.     

Food quality for Eudiaptomus gracilis: the importance of particular highly unsaturated fatty acids

1. Development times and survival of nauplii and copepodites of the freshwater calanoid Eudiaptomus gracilis were measured on comparably sized Cryptomonas sp. and two strains of Chlamydomonas reinhardii under food saturated conditions (1 mg C L−1) to investigate the nutritional quality of these algae.
2.  Cryptomonas sp. supported complete ontogenesis of nauplii to adults, whereas both strains of C. reinhardii were inadequate for the development of nauplii and copepodites and resulted in high mortality. The nutritional deficiency of both strains of C. reinhardii was compensated for by Cryptomonas sp. when the latter constituted ≥50% of dietary carbon. Pulses of Cryptomonas sp. had a similar compensatory effect.
3. In comparison to Cryptomonas sp., both strains of C. reinhardii were deficient in the three highly unsaturated fatty acids (HUFAs) stearidonic, eicosapentaenoic and docosahexaenoic acid. We manipulated the fatty acid content of C. reinhardii by externally adding these three HUFAs to the alga so that the fatty acid profile resembled that of Cryptomonas sp. This supplementation did not improve food quality, however, indicating that the nutritional deficiency of both strains of C. reinhardii for the ontogenesis of E. gracilis is not due to a lack of these three HUFAs.     

Protein disulphide isomerase is required for signal peptide peptidase-mediated protein degradation

The human cytomegalovirus glycoprotein US2 induces dislocation of MHC class I heavy chains from the endoplasmic reticulum (ER) into the cytosol and targets them for proteasomal degradation. Signal peptide peptidase (SPP) has been shown to be integral for US2-induced dislocation of MHC class I heavy chains although its mechanism of action remains poorly understood. Here, we show that knockdown of protein disulphide isomerase (PDI) by RNA-mediated interference inhibited the degradation of MHC class I molecules catalysed by US2 but not by its functional homolog US11. Overexpression of the substrate-binding mutant of PDI, but not the catalytically inactive mutant, dominant-negatively inhibited US2-mediated dislocation of MHC class I molecules by preventing their release from US2. Furthermore, PDI associated with SPP independently of US2 and knockdown of PDI inhibited SPP-mediated degradation of CD3δ but not Derlin-1-dependent degradation of CFTR DeltaF508. Together, our data suggest that PDI is a component of the SPP-mediated ER-associated degradation machinery.     

Models of annual cycles in lentic water bodies

A discussion of mathematical modelling of water quality, including a summary of the parameters considered, a comparison of the two major model types (stochastic and deterministic) and a review of the validation process, is presented. A water quality model currently being developed is discussed and a list of ecological models already developed is given.