Butterfly eyespot serial homology: enter the Hox genes

Hox genes modify serial homology patterns in many organisms, exemplified in vertebrates by modification of the axial skeleton and in arthropods by diversification of the body segments. Butterfly wing eyespots also appear in a serial homologous pattern that, in certain species, is subject to local modification. A paper in EvoDevo reports the Hox gene Antp is the earliest known gene to have eyespot-specific expression; however, not all Lepidoptera express Antp in eyespots, suggesting some developmental flexibility

Fuel cells for power generation and organic waste treatment on the island of Mull

In-situ use of biomass and organic waste streams have the potential to provide the key to energy self sustainability for islands and remote communities. Traditionally biogas fuels have been used in combustion engines for electric power generation. However, fuel cells offer the prospect of achieving higher generating efficiencies, and additionally, important environmental benefits can be achieved by way of mitigating greenhouse gas emissions, whilst providing a carbon sink. This paper presents the design details of a biogas gas plant and fuel cell installation that will provide a practical solution on an island (and be applicable in other remote and rural areas) where connection to the grid can be expensive, and where biofuels can be produced on site at no significant extra cost

A Precessing Numerical Relativity Waveform Surrogate Model for Binary Black Holes: A Gaussian Process Regression Approach

Gravitational wave astrophysics relies heavily on the use of matched filtering both to detect signals in noisy data from detectors, and to perform parameter estimation on those signals. Matched filtering relies upon prior knowledge of the signals expected to be produced by a range of astrophysical systems, such as binary black holes. These waveform signals can be computed using numerical relativity techniques, where the Einstein field equations are solved numerically, and the signal is extracted from the simulation. Numerical relativity simulations are, however, computationally expensive, leading to the need for a surrogate model which can predict waveform signals in regions of the physical parameter space which have not been probed directly by simulation. We present a method for producing such a surrogate using Gaussian process regression which is trained directly on waveforms generated by numerical relativity. This model returns not just a single interpolated value for the waveform at a new point, but a full posterior probability distribution on the predicted value. This model is therefore an ideal component in a Bayesian analysis framework, through which the uncertainty in the interpolation can be taken into account when performing parameter estimation of signals.Comment: 13 pages, with 7 figures. Accepted by Physical Review

The case of JAK-STAT and EGFR cooperation in oncogenesis

This is an open-access article licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License.Drosophila is proving to be a valuable model for studying aggressive tumors induced by the combined activation of EGFR and JAK-STAT signaling. Here we summarize some of the most recent data showing that tissue damage and the modulation of common pathway regulators are at the heart tumor progression and metastasis.Peer reviewe

From organ selector to cell behavior regulator

This is an open-access article licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported License.One of the main contributions of Drosophila to the JAK-STAT field is the study of morphogenesis. JAK-STAT signaling controls the formation of many different structures through surprisingly different morphogenetic behaviors that include induction of cell rearrangements, invagination, folding of tissues, modulation of cell shape, and migration. This variability may be explained by the many transcription factors and signaling molecules STAT regulates at early stages of development. But is STAT just acting as an upstream inducer of morphogenesis or does it have a more direct role in controlling cell behaviors? Here we review what is known about how the canonical phosphorylation of STAT contributes to shaping the embryonic and imaginal structures.This work was supported by the Spanish Ministerio de Investigación Ciencia e Innovación, Consolider, the European Regional Development Fund, and Junta de Andalucía.Peer reviewe

Forces shaping a Hox morphogenetic gene network

The Abdominal-B selector protein induces organogenesis of the posterior spiracles by coordinating an organ-specific gene network. The complexity of this network begs the questions of how it originated and what selective pressures drove its formation. Given that the network likely formed in a piecemeal fashion, with elements recruited sequentially, we studied the consequences of expressing individual effectors of this network in naive epithelial cells.We found that, with exception of the Crossveinless-c (Cv-c) Rho GTPase-activating protein, most effectors exert little morphogenetic effect by themselves. In contrast, Cv-c expression causes cell motility and downregulates epithelial polarity and cell adhesion proteins. These effects differ in cells endogenously expressing Cv-c, which have acquired compensatory mechanisms. In spiracle cells, the down-regulation of polarity and E-cadherin expression caused by Cv-c-induced Rho1 inactivation are compensated for by the simultaneous spiracle up-regulation of guanine nucleotide exchange factor (GEF) proteins, cell polarity, and adhesion molecules. Other epithelial cells that have coopted Cv-c to their morphogenetic gene networks are also resistant to Cv-c's deleterious effects. We propose that cooption of a novel morphogenetic regulator to a selector cascade causes cellular instability, resulting in strong selective pressure that leads that same cascade to recruitmolecules that compensate it. This experimental-based hypothesis proposes how the frequently observed complex organogenetic gene networks are put together.This work was supported by the Spanish Ministerio de Investigación Ciencia e Innovación, Consolider, the European Regional Development Fund, and the Junta de Andalucía.Peer Reviewe

Adaptation and Naturalization in a Linguistic Area: Sinhala Focused Sentences

Proceedings of the Sixth Annual Meeting of the Berkeley Linguistics Society (1980), pp. 28-4

Divergent gene networks select endocrine glands or trachea from a common segmentally repeated precursor in Drosophila

Póster presentado al Joint Spring Meeting of British Society for Developmental Biology and British Society for Cell Biology, celebrado en la Universidad de Warwick (UK) del 17 al 20 de marzo de 2013.The main endocrine organ of Drosophila, the ring gland, is formed by the fusion of the corpora allata (producing Juvenile Hormone), the prothoracic gland (Ecdysone) and the corpus cardiacum (Adipokinetichormone and others). The embryonic origin of the corpus cardiacum from cephalic mesodermal cells has been established, but the origin of the corpora allata (ca) and prothoracic gland (pg) is unknown. We demonstrate that the corpora allata and prothoracic gland develop from cephalic ectodermal cells that in other segments of the body give rise to the trachea. We identify Hox and Vvl as common primary genes required for trachea, corpora allata and prothoracic gland specification; as well as Snail as a specific corpora allata and prothoracic gland gene. Snail controls the ephitelial to mesenchymal transition (EMT) that is one of the major differences between the ring gland and trachea development. We also show that the trachea can be converted into corpora allata or prothoracic gland and viceversa. Our data indicate that endocrine glands and trachea evolved by the divergence of a homologous segmentally repeated structure.Peer Reviewe

JAK/STAT and Hox dynamic interactions in an organogenetic gene cascade

This is an open access article distributed under the terms of the Creative Commons Attribution License.Organogenesis is controlled by gene networks activated by upstream selector genes. During development the gene network is activated stepwise, with a sequential deployment of successive transcription factors and signalling molecules that modify the interaction of the elements of the network as the organ forms. Very little is known about the steps leading from the early specification of the cells that form the organ primordium to the moment when a robust gene network is in place. Here we study in detail how a Hox protein induces during early embryogenesis a simple organogenetic cascade that matures into a complex gene network through the activation of feedback and feed forward interaction loops. To address how the network organization changes during development and how the target genes integrate the genetic information it provides, we analyze in Drosophila the induction of posterior spiracle organogenesis by the Hox gene Abdominal-B (Abd-B). Initially, Abd-B activates in the spiracle primordium a cascade of transcription factors and signalling molecules including the JAK/STAT signalling pathway. We find that at later stages STAT activity feeds back directly into Abd-B, initiating the transformation of the Hox cascade into a gene-network. Focusing on crumbs, a spiracle downstream target gene of Abd-B, we analyze how a modular cis regulatory element integrates the dynamic network information set by Abd-B and the JAK/STAT signalling pathway during development. We describe how a Hox induced genetic cascade transforms into a robust gene network during organogenesis due to the repeated interaction of Abd-B and one of its targets, the JAK/STAT signalling cascade. Our results show that in this network STAT functions not just as a direct transcription factor, but also acts as a >counter-repressor>, uncovering a novel mode for STAT directed transcriptional regulation.JCGH received funding from the Spanish Ministerio de Ciencia y Tecnología BFU2010 www.micinn.es, Ministerio de Economía y Competitividad BFU2013 www.mineco.gob.es, Junta de Andalucía http://www.juntadeandalucia.es/organismos/economiainnovacioncienciayempleo, Programa Consolider and from the European Regional Development Fund.Peer Reviewe

On the Biological Foundations of Language: Recent Advances in Language Acquisition, Deterioration, and Neuroscience Begin to Converge

In this paper, experimental results on the study of language loss in pro- dromal Alzheimer’s disease (AD) in the elderly are linked to experimen- tal results from the study of language acquisition in the child, via a tran- sitional stage of Mild Cognitive Impairment (MCI). Recent brain imag- ing results from a pilot study comparing prodromal AD and normal ag- ing are reported. Both, behavioral results and their underlying neural underpinnings, identify the source of language deficits in MCI as break- down in syntax–semantics integration. These results are linked to inde- pendent discoveries regarding the ontogeny of language in the child and their neural foundations. It is suggested that these convergent results ad- vance our understanding of the true nature of maturational processes in language, allowing us to reconsider a “regression hypothesis” (e.g., Ribot 1881), wherein later acquisition predicts earliest dissolution