Quantitative fluorescence microscopy: from art to science

A substantial number of elegant experimental approaches have been developed to image the distribution and dynamics of DNA, mRNA, proteins, organelles, metabolites, and ions in living plant cells. Although the human brain can rapidly assimilate visual information, particularly when presented as animations and movies, it is much more challenging to condense the phenomenal amount of data present in three-, four-, or even five-dimensional images into statistically useful measurements. This review explores a range of in vivo fluorescence imaging applications in plants, with particular emphasis on where quantitative techniques are beginning to emerge

N-acetylgalactosamine glycans function in cancer cell adhesion to endothelial cells: a role for truncated O-glycans in metastatic mechanisms

Failure in O-glycan chain extension exposing Tn antigen (GalNAc-O-Ser/Thr) is clinically associated with cancer metastasis. This study provides evidence of a functional role for aberrant GalNAc-glycans in cancer cell capture from blood flow and / or adhesion to endothelium. Adhesion of breast cancer cells to human umbilical vein endothelial cell monolayers was modelled under sweeping flow. Adhesion of metastatic, GalNAc glycan-rich, MCF7 and ZR 75 1 cells to endothelium increased over timepoints up to 1.5 hour, after which it plateaued. Adhesion was significantly inhibited (p<0.001) when cell surface GalNAc-glycans were masked, an effect not seen in GalNAc glycan-poor, non-metastatic BT 474 cells. Masking irrelevant galactose- and mannose-glycans had no inhibitory effect. Imaging of cells post-adhesion over a 24 hour time course using confocal and scanning electron microscopy revealed that up to 6 hours post-adhesion, motile, rounded cancer cells featuring lamellipodia-like processes crawled on an intact endothelial monolayer. From 6-12 hours post-adhesion, cancer cells became stationary, adopted a smooth, circular flattened morphology, and endothelial cells retracted from around them leaving cleared zones in which the cancer cells proceeded to form colonies through cell division

Differences in intracellular localisation of ANKH mutants that relate to mechanisms of calcium pyrophosphate deposition disease and craniometaphyseal dysplasia

ANKH mutations are associated with calcium pyrophosphate deposition disease and craniometaphyseal dysplasia. This study investigated the effects of these ANKH mutants on cellular localisation and associated biochemistry. We generated four ANKH overexpression-plasmids containing either calcium pyrophosphate deposition disease or craniometaphyseal dysplasia linked mutations: P5L, E490del and S375del, G389R. They were transfected into CH-8 articular chondrocytes and HEK293 cells. The ANKH mutants dynamic differential localisations were imaged and we investigated the interactions with the autophagy marker LC3. Extracellular inorganic pyrophosphate, mineralization, ENPP1 activity expression of ENPP1, TNAP and PIT-1 were measured. P5L delayed cell membrane localisation but once recruited into the membrane it increased extracellular inorganic pyrophosphate, mineralization, and ENPP1 activity. E490del remained mostly cytoplasmic, forming punctate co-localisations with LC3, increased mineralization, ENPP1 and ENPP1 activity with an initial but unsustained increase in TNAP and PIT-1. S375del trended to decrease extracellular inorganic pyrophosphate, increase mineralization. G389R delayed cell membrane localisation, trended to decrease extracellular inorganic pyrophosphate, increased mineralization and co-localised with LC3. Our results demonstrate a link between pathological localisation of ANKH mutants with different degrees in mineralization. Furthermore, mutant ANKH functions are related to synthesis of defective proteins, inorganic pyrophosphate transport, ENPP1 activity and expression of ENPP1, TNAP and PIT-1

Mental health problems among 4–17-year-olds with hearing problems : results from a nationally representative study

OBJECTIVE : This study aimed to characterize the risk of mental health problems among a representative sample of 6,310 4–17-year-olds, 147 of whom had parent-reported hearing problems. METHODS : The study used data from the Young Minds Matter survey. The Diagnostic Interview Schedule for Children (DISC-IV) assessed prevalence of mood, anxiety and behavioural disorders. The Strengths and Difficulties Questionnaire (SDQ) assessed social and emotional problems. Logistic regression models were used to estimate odds of having mental health problems adjusting for child factors (speech and language problems, global health, age and gender), family factors (family structure, parent income, education, financial strain and psychological distress) and school-related factors (bullying, school liking, school absence). RESULTS : In unadjusted analyses, children and young people with hearing problems had substantially higher odds of most mental health problems. Hearing problems were not associated with any mental health problem among 4–11-year-olds after adjusting for other child factors. After adjustments for child, family and school-related factors, 12–17-year-olds with a hearing problem remained at greater risk of social phobia and generalized anxiety (DISC-IV), and of peer and emotional problems (SDQ). CONCLUSIONS : Clinicians caring for children and young people with hearing problems should be alert for heightened risk of specific mental health problems based on age and the nature of hearing problems. Understanding a wider range of correlates associated with the higher prevalence of mental health problems may allow health professionals to be more informed about the nature of mental health problems that are comorbid to hearing problems.KJH was supported by the Australian Research Centre of Excellence for Children and Families over the Life Course [grant No. CE140100027]. AL was supported by a National Health and Medical Research Council Early Career Fellowship [grant No. 1072593]. The Young Minds Matter survey was initiated and funded by the Australian Government Department of Health.https://www.tandfonline.com/toc/ihbc202018-05-16hj2018Speech-Language Pathology and Audiolog

Epidermal Pavement Cells of Arabidopsis Have Chloroplasts

Letter to edito

Co-evolution of density and topology in a simple model of city formation

We study the influence that population density and the road network have on each others' growth and evolution. We use a simple model of formation and evolution of city roads which reproduces the most important empirical features of street networks in cities. Within this framework, we explicitely introduce the topology of the road network and analyze how it evolves and interact with the evolution of population density. We show that accessibility issues -pushing individuals to get closer to high centrality nodes- lead to high density regions and the appearance of densely populated centers. In particular, this model reproduces the empirical fact that the density profile decreases exponentially from a core district. In this simplified model, the size of the core district depends on the relative importance of transportation and rent costs.Comment: 13 pages, 13 figure

Antisocial behaviour and teacher–student relationship quality: The role of emotion‐related abilities and callous–unemotional traits

Background: Childhood antisocial behaviour has been associated with poorer teacher-student relationship (TSR) quality. It is also well-established that youth with antisocial behaviour have a range of emotion-related deficits, yet the impact of these students’ emotion-related abilities on the TSR is not understood. Furthermore, the addition of the Limited Prosocial Emotions specifier in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) indicates that understanding the role of callous-unemotional (CU) traits for youth with antisocial behaviour problems is of particular importance. Aims: The aim of this study was to investigate the association between antisocial behaviour difficulties and the TSR by examining the influence of emotion-related abilities and CU traits. Sample: Twelve teachers from 10 primary schools provided anonymised information on 108 children aged 6-11 years. Results: Antisocial behaviour was associated with higher teacher-student conflict (but not closeness) as well as higher emotion lability/negativity and lower emotion understanding/empathy. Emotion lability/negativity was associated with higher teacher-student conflict (but not closeness), and emotion understanding/empathy was associated with lower teacher-student conflict and higher closeness. CU traits was associated with higher teacher-student conflict and lower teacher-student closeness (controlling for antisocial behaviour more broadly). We found no evidence of a moderating effect of CU traits or emotion-related abilities on the association between antisocial behaviour and TSR quality. Conclusions: Interventions for behaviour difficulties should consider teacher-student relationships in the classroom. Strategies which aim to improve teacher-student closeness as well as reduce teacher-student conflict may be of particular value to students with high CU traits

Adolescents' involvement in cyber bullying and perceptions of school: the importance of perceived peer acceptance for female adolescents

Young people are spending increasing amounts of time using digital technology and, as such, are at great risk of being involved in cyber bullying as a victim, bully, or bully/victim. Despite cyber bullying typically occurring outside the school environment, the impact of being involved in cyber bullying is likely to spill over to school. Fully 285 11- to 15-year-olds (125 male and 160 female, M age = 12.19 years, SD = 1.03) completed measures of cyber bullying involvement, self-esteem, trust, perceived peer acceptance, and perceptions of the value of learning and the importance of school. For young women, involvement in cyber bullying as a victim, bully, or bully/victim negatively predicted perceptions of learning and school, and perceived peer acceptance mediated this relationship. The results indicated that involvement in cyber bullying negatively predicted perceived peer acceptance which, in turn, positively predicted perceptions of learning and school. For young men, fulfilling the bully/victim role negatively predicted perceptions of learning and school. Consequently, for young women in particular, involvement in cyber bullying spills over to impact perceptions of learning. The findings of the current study highlight how stressors external to the school environment can adversely impact young women's perceptions of school and also have implications for the development of interventions designed to ameliorate the effects of cyber bullying

Mechanical Stress Induces Remodeling of Vascular Networks in Growing Leaves

International audienceDifferentiation into well-defined patterns and tissue growth are recognized as key processes in organismal development. However, it is unclear whether patterns are passively, homogeneously dilated by growth or whether they remodel during tissue expansion. Leaf vascu-lar networks are well-fitted to investigate this issue, since leaves are approximately two-dimensional and grow manyfold in size. Here we study experimentally and computationally how vein patterns affect growth. We first model the growing vasculature as a network of viscoelastic rods and consider its response to external mechanical stress. We use the so-called texture tensor to quantify the local network geometry and reveal that growth is heterogeneous , resembling non-affine deformations in composite materials. We then apply mechanical forces to growing leaves after veins have differentiated, which respond by anisotropic growth and reorientation of the network in the direction of external stress. External mechanical stress appears to make growth more homogeneous, in contrast with the model with viscoelastic rods. However, we reconcile the model with experimental data by incorporating randomness in rod thickness and a threshold in the rod growth law, making the rods viscoelastoplastic. Altogether, we show that the higher stiffness of veins leads to their reorientation along external forces, along with a reduction in growth heterogeneity. This process may lead to the reinforcement of leaves against mechanical stress. More generally , our work contributes to a framework whereby growth and patterns are coordinated through the differences in mechanical properties between cell types