Extra forces evoked during electrical stimulation of the muscle or its nerve are generated and modulated by a length-dependent intrinsic property of muscle in humans and cats.

Extra forces or torques are defined as forces or torques that are larger than would be expected from the input or stimuli, which can be mediated by properties intrinsic to motoneurons and/or to the muscle. The purpose of this study was to determine whether extra forces/torques evoked during electrical stimulation of the muscle or its nerve with variable frequency stimulation are modulated by muscle length/joint angle. A secondary aim was to determine whether extra forces/torques are generated by an intrinsic neuronal or muscle property.

New insights on ctenophore neural anatomy: immunofluorescence study in Pleurobrachia pileus (Müller, 1776).

Ctenophores are non-bilaterian animals sharing with cnidarians and bilaterians the presence of sensory receptors, nerve cells, and synapses, absent in placozoans and sponges. Although recent immunofluorescence studies have renewed our knowledge of cnidarian neuro-anatomy, ctenophores have been much less investigated despite their importance to understanding the origin and early evolution of the nervous system. In this study, the neuro-anatomy of the ctenophore Pleurobrachia pileus (Müller, 1776) was explored by whole-mount fluorescent antibody staining using antibodies against tyrosylated -tubulin, FMRFamide, and vasopressin.

The transcription factor Foxg1 regulates telencephalic progenitor proliferation cell autonomously, in part by controlling Pax6 expression levels.

Background: The transcription factor Foxg1 is an important regulator of telencephalic cell cycles. Its inactivation causes premature lengthening of telencephalic progenitor cell cycles and increased neurogenic divisions, leading to severe hypoplasia of the telencephalon. These proliferation defects could be a secondary consequence of the loss of Foxg1 caused by the abnormal expression of several morphogens (Fibroblast growth factor 8, bone morphogenetic proteins) in the telencephalon of Foxg1 null mutants.

Somatic stem cells express Piwi and Vasa genes in an adult ctenophore: ancient association of "germline genes" with stemness.

Stem cells are essential for animal development and adult tissue homeostasis, and the quest for an ancestral gene fingerprint of stemness is a major challenge for evolutionary developmental biology. Recent studies have indicated that a series of genes, including the transposon silencer Piwi and the translational activator Vasa, specifically involved in germline determination and maintenance in classical bilaterian models (e.g.

Visual screening for early detection of cervical neoplasia in Angola.

Objective: A cross-sectional study in Angola to evaluate the feasibility of cervical screening using visual inspection with acetic acid (VIA) or Lugol's iodine (VILI) to detect and treat cervical intraepithelial neoplasia (CIN).

Methods: All 8851 women screened by trained nurses received colposcopy and/or colposcopically-directed biopsies. The final disease status was based on histopathology or colposcopy when no or inadequate biopsies were done.

Molecular phylogenetics of Thecata (Hydrozoa, Cnidaria) reveals long-term maintenance of life history traits despite high frequency of recent character changes.

Two fundamental life cycle types are recognized among hydrozoan cnidarians, the benthic (generally colonial) polyp stage either producing pelagic sexual medusae or directly releasing gametes elaborated from an attached gonophore. The existence of intermediate forms, with polyps producing simple medusoids, has been classically considered compelling evidence in favor of phyletic gradualism. In order to gain insights about the evolution of hydrozoan life history traits, we inferred phylogenetic relationships of 142 species of Thecata (= Leptothecata, Leptomedusae), the most species-rich hydrozoan group, using 3 different ribosomal RNA markers (16S, 18S, and 28S).

The generation of superficial cortical layers is regulated by levels of the transcription factor Pax6.

The ventricular zone (VZ) of the embryonic dorsal telencephalon is a major site for generating cortical projection neurons. The transcription factor Pax6 is highly expressed in apical progenitors (APs) residing in the VZ from the earliest stages of corticogenesis. Previous studies mainly focused on Pax6(-/-) mice have implicated Pax6 in regulating cortical progenitor proliferation, neurogenesis, and formation of superficial cortical layers.

Improved phylogenomic taxon sampling noticeably affects nonbilaterian relationships.

Despite expanding data sets and advances in phylogenomic methods, deep-level metazoan relationships remain highly controversial. Recent phylogenomic analyses depart from classical concepts in recovering ctenophores as the earliest branching metazoan taxon and propose a sister-group relationship between sponges and cnidarians (e.g.

Laser-driven magnetic-flux compression in high-energy-density plasmas.

The demonstration of magnetic field compression to many tens of megagauss in cylindrical implosions of inertial confinement fusion targets is reported for the first time. The OMEGA laser [T. R.

Clytia hemisphaerica: a jellyfish cousin joins the laboratory.

Clytia hemisphaerica, a member of the early-branching animal phylum Cnidaria, is emerging rapidly as an experimental model for studies in developmental biology and evolution. Unlike the two existing genome-sequenced cnidarian models Nematostella and Hydra, Clytia has a free-swimming jellyfish form, which like "higher" animals (the Bilateria) has a complex organization including striated musculature, specialized nervous system and structured sensory and reproductive organs. Clytia has proved well suited to laboratory culture and to gene function analysis during early development.

A two-population bio-electrochemical model of a microbial fuel cell.

This work presents a two-population model describing the competition of anodophilic and methanogenic microbial populations for a common substrate in a microbial fuel cell (MFC). Fast numerical solution of the model is provided by using ordinary differential equations to describe biomass growth and retention in the anodic compartment. The model parameters are estimated and validated using experimental results obtained in four continuous-flow air-cathode MFCs operated at various external resistances and organic loads.

Convergent origins and rapid evolution of spliced leader trans-splicing in metazoa: insights from the ctenophora and hydrozoa.

Replacement of mRNA 5' UTR sequences by short sequences trans-spliced from specialized, noncoding, spliced leader (SL) RNAs is an enigmatic phenomenon, occurring in a set of distantly related animal groups including urochordates, nematodes, flatworms, and hydra, as well as in Euglenozoa and dinoflagellates. Whether SL trans-splicing has a common evolutionary origin and biological function among different organisms remains unclear. We have undertaken a systematic identification of SL exons in cDNA sequence data sets from non-bilaterian metazoan species and their closest unicellular relatives.

A high throughput metabolic stability screening workflow with automated assessment of data quality in pharmaceutical industry.

One of the most commonly performed in vitro ADME assays during the lead generation and lead optimization stage of drug discovery is metabolic stability evaluation. Metabolic stability is typically assessed in liver microsomes, which contain Phase I metabolizing enzymes, mainly cytochrome P450 enzymes (CYPs). The amount of parent drug metabolized by these CYPs is determined by LC/MS/MS.

New tricks with old genes: the genetic bases of novel cnidarian traits.

Recent thought on genome evolution has focused on the creation of new genes and changes in regulatory mechanisms while ignoring the role of selective gene loss in shaping genomes. Using data from two cnidarians, the jellyfish Clytia and the coral Acropora, we examined the relative significance of new 'taxonomically restricted' genes and selectively retained ancestral genes in enabling the evolution of novel traits. Consistent with its more complex life-cycle, the proportion of novel genes identified in Clytia was higher than that in the 'polyp only' cnidarians Nematostella and Hydra, but each of these cnidarians has retained a proportion of ancestral genes not present in the other two.

The backbone of the post-synaptic density originated in a unicellular ancestor of choanoflagellates and metazoans.

Background: Comparative genomics of the early diverging metazoan lineages and of their unicellular sister-groups opens new window to reconstructing the genetic changes which preceded or accompanied the evolution of multicellular body plans. A recent analysis found that the genome of the nerve-less sponges encodes the homologues of most vertebrate post-synaptic proteins. In vertebrate excitatory synapses, these proteins assemble to form the post-synaptic density, a complex molecular platform linking membrane receptors, components of their signalling pathways, and the cytoskeleton.

The transcription factor Foxg1 regulates the competence of telencephalic cells to adopt subpallial fates in mice.

Foxg1 is required for development of the ventral telencephalon in the embryonic mammalian forebrain. Although one existing hypothesis suggests that failed ventral telencephalic development in the absence of Foxg1 is due to reduced production of the morphogens sonic hedgehog (Shh) and fibroblast growth factor 8 (Fgf8), the possibility that telencephalic cells lacking Foxg1 are intrinsically incompetent to generate the ventral telencephalon has remained untested. We examined the ability of Foxg1(-/-) telencephalic cells to respond to Shh and Fgf8 by examining the expression of genes whose activation requires Shh or Fgf8 in vivo and by testing their responses to Shh and Fgf8 in culture.

Fast kinetics, high-frequency oscillations, and subprimary firing range in adult mouse spinal motoneurons.

The fast contraction time of mouse motor units creates a unique situation in which motoneurons have to fire at low frequencies to produce small forces but also at very high frequency (much higher than in cat or rat motoneurons) to reach the fusion frequency of their motor units. To understand how this problem is solved, we performed intracellular recordings of adult mouse spinal motoneurons and investigated systematically their subthreshold properties and their discharge pattern. We show that mouse motoneurons have a much wider range of firing frequencies than cat and rat motoneurons because of three salient features.

High diversity of the immune repertoire in humanized NOD.SCID.gamma c-/- mice.

The diversity of the human immune repertoire and how it relates to a functional immune response has not yet been studied in detail in humanized NOD.SCID.gammac(-/-) immunodeficient mice.

Phylogenomics revives traditional views on deep animal relationships.

The origin of many of the defining features of animal body plans, such as symmetry, nervous system, and the mesoderm, remains shrouded in mystery because of major uncertainty regarding the emergence order of the early branching taxa: the sponge groups, ctenophores, placozoans, cnidarians, and bilaterians. The "phylogenomic" approach [1] has recently provided a robust picture for intrabilaterian relationships [2, 3] but not yet for more early branching metazoan clades. We have assembled a comprehensive 128 gene data set including newly generated sequence data from ctenophores, cnidarians, and all four main sponge groups.

Early evolution of symmetry and polarity in metazoan body plans.

The early diverging metazoan lineages have highly disparate adult body plan geometries, which can be characterised in terms of five major types of symmetry (asymmetrical, spherical, cylindrical, n-radial, bilateral). Patterns of evolutionary changes in symmetry types and the homology of body axes across lineages are discussed here by confronting evidence from comparative anatomy, phylogeny, genomics and evo-devo. The conventional scenario, postulating a graded complexification from asymmetry to radial and finally bilateral symmetry, is considered untenable.

Are Hox genes ancestrally involved in axial patterning? Evidence from the hydrozoan Clytia hemisphaerica (Cnidaria).

Background: The early evolution and diversification of Hox-related genes in eumetazoans has been the subject of conflicting hypotheses concerning the evolutionary conservation of their role in axial patterning and the pre-bilaterian origin of the Hox and ParaHox clusters. The diversification of Hox/ParaHox genes clearly predates the origin of bilaterians. However, the existence of a "Hox code" predating the cnidarian-bilaterian ancestor and supporting the deep homology of axes is more controversial.

Insights into the early evolution of SOX genes from expression analyses in a ctenophore.

SOX genes encode transcription factors acting in various developmental processes in bilaterian animals, such as stem cell maintenance and the control of specification and differentiation of cell types in a variety of contexts, notably in the developing nervous system. To gain insights into the early evolution of this important family of developmental regulators, we investigated the expression of one subgroup B, two subgroup E, one subgroup F and two divergent SOX genes in the cydippid larva and in the adult of the ctenophore Pleurobrachia pileus. Transcripts of the two unclassified SOX (PpiSOX2/12) were detected in the female germ line and in various populations of putative somatic stem cells/undifferentiated progenitors.