Preliminary Characterization of Voltage-Activated Whole-Cell Currents in Developing Human Vestibular Hair Cells and Calyx Afferent Terminals

We present preliminary functional data from human vestibular hair cells and primary afferent calyx terminals during fetal development. Whole-cell recordings were obtained from hair cells or calyx terminals in semi-intact cristae prepared from human fetuses aged between 11 and 18 weeks gestation (WG). During early fetal development (11–14 WG), hair cells expressed whole-cell conductances that were qualitatively similar but quantitatively smaller than those observed previously in mature rodent type II hair cells. As development progressed (15–18 WG), peak outward conductances increased in putative type II hair cells but did not reach amplitudes observed in adult human hair cells. Type I hair cells express a specific low-voltage activating conductance, G(K,L). A similar current was first observed at 15 WG but remained relatively small, even at 18 WG. The presence of a “collapsing” tail current indicates a maturing type I hair cell phenotype and suggests the presence of a surrounding calyx afferent terminal. We were also able to record from calyx afferent terminals in 15–18 WG cristae. In voltage clamp, these terminals exhibited fast inactivating inward as well as slower outward conductances, and in current clamp, discharged a single action potential during depolarizing steps. Together, these data suggest the major functional characteristics of type I and type II hair cells and calyx terminals are present by 18 WG. Our study also describes a new preparation for the functional investigation of key events that occur during maturation of human vestibular organs

High Harmonic Spectroscopy of the Cooper Minimum in Molecules

The Cooper minimum (CM) has been studied using high harmonic generation solely in atoms. Here, we present detailed experimental and theoretical studies on the CM in molecules probed by high harmonic generation using a range of near-infrared light pulses from λ = 1.3 to 1.8 µm. We demonstrate the CM to occur in CS₂ and CCl₄ at ~42 and ~40 eV, respectively, by comparing the high harmonic spectra with the known partial photoionization cross sections of different molecular orbitals, confirmed by theoretical calculations of harmonic spectra. We use CM to probe electron localization in Cl-containing molecules (CCl₄, CH₂Cl₂, and trans-C₂H₂Cl₂) and show that the position of the minimum is influenced by the molecular environment

Comparative Study of Monoclonal and Recombinant Antibody-Based Immunoassays for Fungicide Analysis in Fruit juices

[EN] A comparative study of the analytical performance of enzyme-linked immunosorbent assays (ELISAs), based on monoclonal and recombinant antibodies, for the determination of fungicide residues in fruit juices has been carried out. To this aim, three murine hybridoma cell lines secreting specific monoclonal antibodies against (RS)-2-(2,4-dichlorophenyl)-3-(1H-1,2,4-triazol-1-yl)propyl-1,1,2,2-tetrafluoroethyl ether (tetraconazole), 2-(4-triazolyl)benzimidazole (thiabendazole), and (RS)-1-(beta-allyloxy-2,4-dichlorophenylethyl)imidazole (imazalil) were used as a source of immunoglobulin gene fragments for the production of single-chain variable fragment (scFv) and fusion scFv-pIII recombinant antibodies in Escherichia coli. Selected recombinant antibodies displayed cross-reactivity profiles very similar to those of the parent monoclonal antibodies. Imazalil and tetraconazole recombinant antibodies showed one order of magnitude lower affinity than their respective monoclonal antibodies, whereas the thiabendazole recombinant antibodies showed an affinity similar to that of their parent monoclonal antibody. On the other hand, scFv-pIII fusion fragments showed similar analytical properties as, and occasionally better than, scFv recombinant antibodies. Finally, ELISAs developed from each antibody type showed similar analytical performance when applied to the analysis of the target fungicides in fruit juices.This work was funded by Ministerio de Educacion y Ciencia (MEC, Spain, Project AGL2002-03266). E. P. was the recipient of a doctoral fellowship from Conselleria d'Educacio (Generalitat Valenciana, Spain).Moreno Tamarit, MJ.; Plana Andani, E.; Manclus Ciscar, JJ.; Montoya Baides, Á. (2014). Comparative Study of Monoclonal and Recombinant Antibody-Based Immunoassays for Fungicide Analysis in Fruit juices. Food Analytical Methods. 7(2):481-489. https://doi.org/10.1007/s12161-013-9655-zS48148972Abad A, Manclús JJ, Moreno M, Montoya A (2001) J AOAC Int 84:1–6Alcocer MJC, Doyen C, Lee HA, Morgan MRA (2000) J Agric Food Chem 48:4053–4059Brichta J, Vesela H, Franek M (2003) Vet Med 48:237–247Brichta J, Hnilova M, Viskovic T (2005) Vet Med 50:231–252Charlton K, Harris WJ, Potter AJ (2001) Biosens Bioelec 16:639–646EU Pesticide Database (2013) Pesticide EU-MRLs. http://ec.europa.eu/sanco_pesticides/public/index.cfm . Accessed Jan 2013Ferrer C, Martínez-Bueno MJ, Lozano A, Fernández-Alba AR (2011) Talanta 83:1552–1561Garret SD, Appleford DJA, Wyatt GM, Lee HA, Morgan MRA (1997) J Agric Food Chem 45:4183–4189Graham BM, Porter AJ, Harris WJ (1995) J Chem Technol Biotech 63:279–289Hiemstra M, de Kok A (2007) J Chromatog A 1154:3–25Kipriyanov SM, Moldenhauer G, Little M (1997) J Immunol Meth 200:69–77Kramer K, Hock B (2007) Recombinant antibodies for agrochemicals: Evolutionary optimization. In: Kennedy IR, Solomon KR, Gee SJ, Crossan AN, Wang S, Sánchez-Bayo F (eds) Rational environmental management of agrochemicals: Risk assessment, monitoring, and remedial action. ACS Symposium Series, vol. 966, pp 155−170Krebber A, Bornhauser S, Burmester J, Honegger A, Willuda J, Bosshard HR, Plückthun A (1997) J Immunol Meth 201:35–55Leong SSJ, Chen WN (2008) Chem Engin Sci 63:1401–1414Li T, Zhang Q, Liu Y, Chen D, Hu B, Blake DA, Liu F (2006) J Agric Food Chem 54:9085–9091Manclús JJ, Moreno M, Plana E, Montoya A (2008) J Agric Food Chem 56:8790–8800Markus V, Janne L, Urpo L (2011) Trends Anal Chem 30:219–226Mersmann M, Schmidt A, Tesar M, Schöneberg A, Welschof M, Kipriyanov S, Terness P, Little M, Pfizenmaier K, Moosmayer D (1998) J Immunol Meth 220:51–58Moreno M, Plana E, Montoya A, Caputo P, Manclús JJ (2007) Food Addit Contam 24:704–712Morozova VS, Levashova AI, Eremin SA (2005) J Anal Chem 60:202–217Nishi K, Imajuku Y, Nakata M, Ohde K, Miyake S, Morimune K, Kawata M, Ohkawa H (2003) J Pest Sci 28:301–309Nishi K, Ishiuchi M, Morimune K, Ohkawa H (2005) J Agric Food Chem 53:5096–5104Scholthof KB, Whang G, Karu AE (1997) J Agric Food Chem 45:1509–1517Sheedy C, MacKenzie CR, Hall JC (2007) Biotech Adv 25:25333–25352Tout NL, Yau KYF, Trevors JT, Lee H, Hall JC (2001) J Agric Food Chem 49:3628–3637Webb SR, Lee H, Hall JC (1997) J Agric Food Chem 45:535–541Yau KYF, Tout NL, Trevors JT, Lee H, Hall JC (1998) J Agric Food Chem 46:4457–4463Yoshioka N, Akiyama Y, Matsuoka T, Mitsuhashi T (2010) Food Control 21:212–21

Widespread Vestibular Activation of the Rodent Cortex

Much of our understanding of the neuronal mechanisms of spatial navigation is derived from chronic recordings in rodents in which head-direction, place, and grid cells have all been described. However, despite the proposed importance of self-reference information to these internal representations of space, their congruence with vestibular signaling remains unclear. Here we have undertaken brain-wide functional mapping using both fMRI and electrophysiological methods to directly determine the spatial extent, strength, and time course of vestibular signaling across the rat forebrain. We find distributed activity throughout thalamic, limbic, and particularly primary sensory cortical areas in addition to known head-direction pathways. We also observe activation of frontal regions, including infralimbic and cingulate cortices, indicating integration of vestibular information throughout functionally diverse cortical regions. These whole-brain activity maps therefore suggest a widespread contribution of vestibular signaling to a self-centered framework for multimodal sensorimotor integration in support of movement planning, execution, spatial navigation, and autonomic responses to gravito-inertial changes

An ∼140-kb Deletion Associated with Feline Spinal Muscular Atrophy Implies an Essential LIX1 Function for Motor Neuron Survival

The leading genetic cause of infant mortality is spinal muscular atrophy (SMA), a clinically and genetically heterogeneous group of disorders. Previously we described a domestic cat model of autosomal recessive, juvenile-onset SMA similar to human SMA type III. Here we report results of a whole-genome scan for linkage in the feline SMA pedigree using recently developed species-specific and comparative mapping resources. We identified a novel SMA gene candidate, LIX1, in an ~140-kb deletion on feline chromosome A1q in a region of conserved synteny to human chromosome 5q15. Though LIX1 function is unknown, the predicted secondary structure is compatible with a role in RNA metabolism. LIX1 expression is largely restricted to the central nervous system, primarily in spinal motor neurons, thus offering explanation of the tissue restriction of pathology in feline SMA. An exon sequence screen of 25 human SMA cases, not otherwise explicable by mutations at the SMN1 locus, failed to identify comparable LIX1 mutations. Nonetheless, a LIX1-associated etiology in feline SMA implicates a previously undetected mechanism of motor neuron maintenance and mandates consideration of LIX1 as a candidate gene in human SMA when SMN1 mutations are not found

Genetic and expression studies of SMN2 gene in Russian patients with spinal muscular atrophy type II and III

<p>Abstract</p> <p>Background</p> <p>Spinal muscular atrophy (SMA type I, II and III) is an autosomal recessive neuromuscular disorder caused by mutations in the survival motor neuron gene (<it>SMN1</it>). <it>SMN2 </it>is a centromeric copy gene that has been characterized as a major modifier of SMA severity. SMA type I patients have one or two <it>SMN2 </it>copies while most SMA type II patients carry three <it>SMN2 </it>copies and SMA III patients have three or four <it>SMN2 </it>copies. The <it>SMN1 </it>gene produces a full-length transcript (FL-SMN) while <it>SMN2 </it>is only able to produce a small portion of the FL-SMN because of a splice mutation which results in the production of abnormal SMNΔ7 mRNA.</p> <p>Methods</p> <p>In this study we performed quantification of the <it>SMN2 </it>gene copy number in Russian patients affected by SMA type II and III (42 and 19 patients, respectively) by means of real-time PCR. Moreover, we present two families consisting of asymptomatic carriers of a homozygous absence of the <it>SMN1 </it>gene. We also developed a novel RT-qPCR-based assay to determine the FL-SMN/SMNΔ7 mRNA ratio as SMA biomarker.</p> <p>Results</p> <p>Comparison of the <it>SMN2 </it>copy number and clinical features revealed a significant correlation between mild clinical phenotype (SMA type III) and presence of four copies of the <it>SMN2 </it>gene. In both asymptomatic cases we found an increased number of <it>SMN2 </it>copies in the healthy carriers and a biallelic <it>SMN1 </it>absence. Furthermore, the novel assay revealed a difference between SMA patients and healthy controls.</p> <p>Conclusions</p> <p>We suggest that the <it>SMN2 </it>gene copy quantification in SMA patients could be used as a prognostic tool for discrimination between the SMA type II and SMA type III diagnoses, whereas the FL-SMN/SMNΔ7 mRNA ratio could be a useful biomarker for detecting changes during SMA pharmacotherapy.</p