Fast fluorescence microscopy for imaging the dynamics of embryonic development

Live imaging has gained a pivotal role in developmental biology since it increasingly allows real-time observation of cell behavior in intact organisms. Microscopes that can capture the dynamics of ever-faster biological events, fluorescent markers optimal for in vivo imaging, and, finally, adapted reconstruction and analysis programs to complete data flow all contribute to this success. Focusing on temporal resolution, we discuss how fast imaging can be achieved with minimal prejudice to spatial resolution, photon count, or to reliably and automatically analyze images. In particular, we show how integrated approaches to imaging that combine bright fluorescent probes, fast microscopes, and custom post-processing techniques can address the kinetics of biological systems at multiple scales. Finally, we discuss remaining challenges and opportunities for further advances in this field

Values - reviewing the construct and drawing implications for values work in organisation and leadership. Kap. 2

I: H.Askeland, G. Espedal, B. Jelstad Løvaas & S. Sirris (Eds.), Understanding values work : Institutional perspectives in organizations and leadershipThis chapter outlines the trajectory of values, particularly within streams of organisational institutionalism, in order to analyse its application to values work in organisation and leadership. Conveying a frame for discussing values work, it aims at clarifying how to conceptualise the term values. Discussing classic and recent contributions, the chapter proposes seeing values as individual and collective conceptions of desirable trans-situational behaviours, objectives and ideals, serving to guide or valuate practice. Despite being an essential part of defining organisational institutionalism, and its sub-streams, values are seldom explicated. Utilising values in organisational and leadership research requires attention to their situatedness in contexts, and this chapter argues they are salient to organisations operating in pluralistic institutional environment. Studying values work, attention should be given to who and how such work is performed.publishedVersio

Socioeconomic position and overweight among adolescents: data from birth cohort studies in Brazil and the UK

<p>Abstract</p> <p>Background</p> <p>Developed and developing countries are facing rapid increases in overweight and obesity among children and adolescents. The patterns of overweight/obesity differ by age, sex, rural or urban residence and socioeconomic position (SEP) and vary between and within countries.</p> <p>Methods</p> <p>We investigated patterns of SEP – overweight status association among adolescents from the UK (ALSPAC) and Brazil (the 1982 and 1993 Pelotas birth cohort studies).</p> <p>All analyses were performed separately for males and females. Logistic regression analysis was used to examine the relationships between overweight status and two SEP indicators – family income and maternal education.</p> <p>Results</p> <p>A strong positive association was observed in 11-year-old boys from the 1993 Pelotas cohort, with higher prevalence of overweight among the least poor and among those whose mothers had more years of schooling (<it>x</it>²for linear trend p < 0.001). In ALSPAC study higher prevalence of overweight was seen among boys whose mothers had lower educational achievement (<it>x</it>²for linear trend p = 0.006). Among 11 year-old girls from 1993 Pelotas cohort study there was a positive association (higher prevalence of overweight in the higher socioeconomic and educational strata, <it>x</it>²for linear trend p < 0.001 and p = 0.01, respectively) while an inverse association was found in the ALSPAC study (<it>x</it>²for linear trend p < 0.001). Among males from the 1982 cohort study, overweight at 18 years of age showed a positive association with both SEP indicators while among females, the reverse association was found.</p> <p>Conclusion</p> <p>The results of this study demonstrate that the social patterning of overweight varies between and within populations over time. Specific approaches should be developed within populations in order to contain the obesity epidemic and reduce disparities.</p

Zeta Inhibitory Peptide attenuates learning and memory by inducing NO-mediated downregulation of AMPA receptors

Zeta inhibitory peptide (ZIP), a PKMζ inhibitor, is widely used to interfere with the main- tenance of acquired memories. ZIP is able to erase memory even in the absence of PKMζ, via an unknown mechanism. We found that ZIP induces redistribution of the AMPARGluA1 in HEK293 cells and primary cortical neurons, and decreases AMPAR-mediated currents in the nucleus accumbens (NAc). These effects were mimicked by free arginine or by a modified ZIP in which all but the arginine residues were replaced by alanine. Redistribution was blocked by a peptidase-resistant version of ZIP and by treatment with the nitric oxide (NO)- synthase inhibitor L-NAME. ZIP increased GluA1-S831 phosphorylation and ZIP-induced redistribution was blocked by nitrosyl-mutant GluA1-C875S or serine-mutant GluA1-S831A. Introducing the cleavable arginine-alanine peptide into the NAc attenuated expression of cocaine-conditioned reward. Together, these results suggest that ZIP may act as an arginine donor, facilitating NO-dependent downregulation of AMPARs, thereby attenuating learning and memory

Resolving Individuals Contributing Trace Amounts of DNA to Highly Complex Mixtures Using High-Density SNP Genotyping Microarrays

We use high-density single nucleotide polymorphism (SNP) genotyping microarrays to demonstrate the ability to accurately and robustly determine whether individuals are in a complex genomic DNA mixture. We first develop a theoretical framework for detecting an individual's presence within a mixture, then show, through simulations, the limits associated with our method, and finally demonstrate experimentally the identification of the presence of genomic DNA of specific individuals within a series of highly complex genomic mixtures, including mixtures where an individual contributes less than 0.1% of the total genomic DNA. These findings shift the perceived utility of SNPs for identifying individual trace contributors within a forensics mixture, and suggest future research efforts into assessing the viability of previously sub-optimal DNA sources due to sample contamination. These findings also suggest that composite statistics across cohorts, such as allele frequency or genotype counts, do not mask identity within genome-wide association studies. The implications of these findings are discussed

Molecular and cellular mechanisms underlying the evolution of form and function in the amniote jaw.

The amniote jaw complex is a remarkable amalgamation of derivatives from distinct embryonic cell lineages. During development, the cells in these lineages experience concerted movements, migrations, and signaling interactions that take them from their initial origins to their final destinations and imbue their derivatives with aspects of form including their axial orientation, anatomical identity, size, and shape. Perturbations along the way can produce defects and disease, but also generate the variation necessary for jaw evolution and adaptation. We focus on molecular and cellular mechanisms that regulate form in the amniote jaw complex, and that enable structural and functional integration. Special emphasis is placed on the role of cranial neural crest mesenchyme (NCM) during the species-specific patterning of bone, cartilage, tendon, muscle, and other jaw tissues. We also address the effects of biomechanical forces during jaw development and discuss ways in which certain molecular and cellular responses add adaptive and evolutionary plasticity to jaw morphology. Overall, we highlight how variation in molecular and cellular programs can promote the phenomenal diversity and functional morphology achieved during amniote jaw evolution or lead to the range of jaw defects and disease that affect the human condition

K-Ras Mediated Murine Epidermal Tumorigenesis Is Dependent upon and Associated with Elevated Rac1 Activity

A common goal for potential cancer therapies is the identification of differences in protein expression or activity that would allow for the selective targeting of tumor vs. normal cells. The Ras proto-oncogene family (K-Ras, H-Ras and N-Ras) are amongst the most frequently mutated genes in human cancers. As a result, there has been substantial effort dedicated to determining which pathways are activated by Ras signaling and, more importantly, which of these contribute to cancer. Although the most widely studied Ras-regulated signaling pathway is the Raf/mitogen-activated protein kinase cascade, previous research in model systems has revealed that the Rac1 GTP-binding protein is also required for Ras-induced biological responses. However, what have been lacking are rigorous in vivo Rac1 target validation data and a clear demonstration that in Ras-driven hyperplastic lesions, Rac1 activity is increased. Using a combination of genetically-modified mouse models that allow for the tissue-selective activation or deletion of signaling molecules and an activation-state sensitive Rac1 antibody that detects GTP-bound Rac1, we found that Rac1 contributes to K-Ras induced epidermal papilloma initiation and growth and that Rac1 activity is elevated by oncogenic K-Ras in vivo. Previously, it was not practical to assess Rac1 activation status in the most commonly used format for clinical tumor specimens, formalin-fixed paraffin embedded (FFPE) tissues samples. However, this study clearly demonstrates that Rac1 is essential for K-Ras driven epithelial cell hyperproliferation and that Rac1 activity is elevated in tissues expressing mutant oncogenic K-Ras, while also characterizing the activation-state specific Rac1-GTP antibody as a probe to examine Rac1 activation status in FFPE samples. Our findings will facilitate further research on the status of Rac1 activity in human tumors and will help to define the tumor types of the patient population that could potentially benefit from therapies targeting Rac activation or downstream effector signaling pathways