Synchrotron imaging assessment of bone quality

Bone is a complex hierarchical structure and its principal function is to resist mechanical forces and fracture. Bone strength depends not only on the quantity of bone tissue but also on the shape and hierarchical structure. The hierarchical levels are interrelated, especially the micro-architecture, collagen and mineral components; hence analysis of their specific roles in bone strength and stiffness is difficult. Synchrotron imaging technologies including micro-CT and small/wide angle X-Ray scattering/diffraction are becoming increasingly popular for studying bone because the images can resolve deformations in the micro-architecture and collagen-mineral matrix under in situ mechanical loading. Synchrotron cannot be directly applied in-vivo due to the high radiation dose but will allow researchers to carry out systematic multifaceted studies of bone ex-vivo. Identifying characteristics of aging and disease will underpin future efforts to generate novel devices and interventional therapies for assessing and promoting healthy aging. With our own research work as examples, this paper introduces how synchrotron imaging technology can be used with in-situ testing in bone research

Transient cognitive dynamics, metastability, and decision making

Transient Cognitive Dynamics, Metastability, and Decision Making. Rabinovich et al. PLoS Computational Biology. 2008. 4(5) doi:10.1371/journal.pcbi.1000072The idea that cognitive activity can be understood using nonlinear dynamics has been intensively discussed at length for the last 15 years. One of the popular points of view is that metastable states play a key role in the execution of cognitive functions. Experimental and modeling studies suggest that most of these functions are the result of transient activity of large-scale brain networks in the presence of noise. Such transients may consist of a sequential switching between different metastable cognitive states. The main problem faced when using dynamical theory to describe transient cognitive processes is the fundamental contradiction between reproducibility and flexibility of transient behavior. In this paper, we propose a theoretical description of transient cognitive dynamics based on the interaction of functionally dependent metastable cognitive states. The mathematical image of such transient activity is a stable heteroclinic channel, i.e., a set of trajectories in the vicinity of a heteroclinic skeleton that consists of saddles and unstable separatrices that connect their surroundings. We suggest a basic mathematical model, a strongly dissipative dynamical system, and formulate the conditions for the robustness and reproducibility of cognitive transients that satisfy the competing requirements for stability and flexibility. Based on this approach, we describe here an effective solution for the problem of sequential decision making, represented as a fixed time game: a player takes sequential actions in a changing noisy environment so as to maximize a cumulative reward. As we predict and verify in computer simulations, noise plays an important role in optimizing the gain.This work was supported by ONR N00014-07-1-0741. PV acknowledges support from Spanish BFU2006-07902/BFI and CAM S-SEM-0255-2006

Genomic stability in Arabidopsis thaliana transgenic plants obtained by floral dip

. The occurrence of DNA modification is an undesired phenomenon accompanying plant cell transformation. The event has been correlated with the stress imposed by the presently utilised transformation procedures, all depending on plant differentiation from in vitro cell culture, but other causes have not been excluded. In this work, transgenic Arabidopsis thaliana plants have been produced by an approach that does not require cell dedifferentiation, being based on in planta Agrobacterium-mediated gene transfer by flower infiltration, which is followed by recovery and selection of transgenic progeny. Genomic DNA changes in transgenic and control plants have been investigated by AFLP and RAMP analysis. Results show no statistically relevant genomic modifications in transgenic plants, as compared with control untreated plants. Variations were observed in callus-derived A. thaliana plants, thus supporting the conclusion that somaclonal variation is essentially correlated with the stress imposed by the in vitro cell culture, rather than with the integration of a foreign gene

Advancing the Role of Food Processing for Improved Integration in Sustainable Food Chains

Food scientists need to work together with agriculturists, nutritionists, civil society, and governments to develop an integrative approach to feed a growing population sustainably. Current attention on food sustainability mainly concentrates on production agriculture and on nutrition, health, and well-being. Food processing, the necessary conversion of raw materials to edible, functional, and culturally acceptable food products, is an important link between production and consumption within the food value chain. Without increased attention to the role of food processing for a maintainable food supply, we are unlikely to succeed in addressing the mounting challenges in delivering sustainable diets for all people. The objective is to draw on multidisciplinary insights to demonstrate why food processing is integral to a future food supply. We aim to exemplify the importance of essential relevant sustainability indicators and impact assessment for developing informed strategies to feed the world within planetary boundaries. We provide a brief outlook on sustainable food sources, review food processing, and recommend future directions. We highlight the challenges and suggest strategies for improving the sustainability of food systems, to hopefully provide a catalyst for considering implementable initiatives for improving food and nutrition security

Trehalose-based Siamese twin amphiphiles with tunable self-assembling, DNA nanocomplexing and gene delivery properties

An original family of multivalent vectors encompassing gemini and facial amphiphilicity, namely cationic Siamese twin surfactants, has been prepared from the disaccharide trehalose; molecular engineering lets us modulate the self-assembling properties and the topology of the nanocomplexes with plasmid DNA for efficient gene delivery in vitro and in vivo.MINECO SAF2016-76083-R CTQ2015- 64425-C2-1-R CTQ2015-64425-C2-2-R RTI2018-097609-B-C21 RTI2018-097609-B-C22MCIU SAF2016-76083-R CTQ2015- 64425-C2-1-R CTQ2015-64425-C2-2-R RTI2018-097609-B-C21 RTI2018-097609-B-C22Junta de Andalucía FQM2012-1467FEDERFS

An Improved In Vivo Methodology to Visualise Tumour Induced Changes in Vasculature Using the Chick Chorionic Allantoic Membrane Assay

Background/Aim: Decreasing the vascularity of a tumour has proven to be an effective strategy to suppress tumour growth and metastasis. Anti-angiogenic therapies have revolutionized the treatment of advanced-stage cancers, however there is still demand for further improvement. This necessitates new experimental models that will allow researchers to reliably study aspects of angiogenesis. The aim of this study was to demonstrate an in vivo technique in which the highly vascular and accessible chorioallantoic membrane (CAM) of the chick embryo is used to study tumour-induced changes in the macro and microvessels. Materials and Methods: Two cancer cell lines (human melanoma (C8161) and human prostate cancer (PC3)) were selected as model cells. Human dermal fibroblasts were used as a control. One million cells were labelled with green fluorescent protein and implanted on the CAM of the chick embryo at embryonic development day (EDD) 7 and angiogenesis was evaluated at EDDs 10, 12 and 14. A fluorescently-tagged lectin (lens culinaris agglutinin (LCA)) was injected intravenously into the chick embryo to label endothelial cells. The LCA is known to label the luminal surface of endothelial cells, or dextrans, in the CAM vasculature. Macrovessels were imaged by a hand-held digital microscope and images were processed for quantification. Microvessels were evaluated by confocal microscopy. Tumour invasion was assessed by histological and optical sectioning. Results: Tumour cells (C8161 and PC3) produced quantifiable increases in the total area covered by blood vessels, compared to fibroblasts when assessed by digital microscopy. Tumour invasion could be demonstrated by both histological and optical sectioning. The most significant changes in tumour vasculature observed were in the microvascular structures adjacent to the tumour cells, which showed an increase in the endothelial cell coverage. Additionally, tumour intravasation and tumour thrombus formation could be detected in the areas adjacent to tumour cells. The fragility of tumour blood vessels could be demonstrated when tumour cells seeded on a synthetic scaffold were grown on CAM. Conclusion: We report on a modification to a well-studied CAM in vivo assay, which can be effectively used to study tumour induced changes in macro and microvasculature

Development of 3D human intestinal equivalents for substance testing in microliter-scale on a multi-organ-chip : From 23rd European Society for Animal Cell Technology (ESACT) Meeting: Better Cells for Better Health Lille, France. 23-26 June 2013

First published by BioMed Central: Jaenicke, Annika; Tordy, Dominique; Groeber, Florian; Hansmann, Jan; Nietzer, Sarah; Tripp, Carolin; Walles, Heike; Lauster, Roland; Marx, Uwe: Development of 3D human intestinal equivalents for substance testing in microliter-scale on a multi-organ-chip. - In: BMC Proceedings. - ISSN 1753-6561 (online). - 7 (2013), suppl. 6, P65. - doi:10.1186/1753-6561-7-S6-P65

Broadly permissive intestinal chromatin underlies lateral inhibition and cell plasticity

Cells differentiate when transcription factors (TFs) bind accessible cis-regulatory elements to establish specific gene expression programs. In differentiating embryonic stem (ES) cells, chromatin at lineage-restricted genes becomes sequentially accessible1-4, probably by virtue of “pioneer” TF activity5, but tissues may utilize other strategies in vivo. Lateral inhibition is a pervasive process in which one cell forces a different identity on its neighbors6, and it is unclear how chromatin in equipotent progenitors undergoing lateral inhibition quickly enables distinct, transiently reversible cell fates. Here we report the chromatin and transcriptional underpinnings of differentiation in mouse small intestine crypts, where Notch signaling mediates lateral inhibition to assign progenitor cells into absorptive or secretory lineages7-9. Transcript profiles in isolated LGR5+ intestinal stem cells (ISC)10 and secretory and absorptive progenitors indicated that each cell population was distinct and the progenitors specified. Nevertheless, secretory and absorptive progenitors showed comparable levels of H3K4me2 and H3K27ac histone marks and DNaseI hypersensitivity - signifying accessible, permissive chromatin - at most of the same cis-elements. Enhancers acting uniquely in progenitors were well-demarcated in LGR5+ ISC, revealing early priming of chromatin for divergent transcriptional programs, and retained active marks well after lineages were specified. On this chromatin background, ATOH1, a secretory-specific TF, controls lateral inhibition through Delta-like Notch ligand genes and also drives numerous secretory lineage genes. Depletion of ATOH1 from specified secretory cells converted them into functional enterocytes, indicating prolonged responsiveness of marked enhancers to presence or absence of a key TF. Thus, lateral inhibition and intestinal crypt lineage plasticity involve interaction of a lineage-restricted TF with broadly permissive chromatin established in multipotent stem cells

Highly parallel assays of tissue-specific enhancers in whole Drosophila embryos

Transcriptional enhancers are a primary mechanism by which tissue-specific gene expression is achieved. Despite the importance of these regulatory elements in development, responses to environmental stresses, and disease, testing enhancer activity in animals remains tedious, with a minority of enhancers having been characterized. Here, we have developed ‘enhancer-FACS-Seq’ (eFS) technology for highly parallel identification of active, tissue-specific enhancers in Drosophila embryos. Analysis of enhancers identified by eFS to be active in mesodermal tissues revealed enriched DNA binding site motifs of known and putative, novel mesodermal transcription factors (TFs). Naïve Bayes classifiers using TF binding site motifs accurately predicted mesodermal enhancer activity. Application of eFS to other cell types and organisms should accelerate the cataloging of enhancers and understanding how transcriptional regulation is encoded within them