Search results for "Vertebra"

Centrins, gatekeepers for the light-dependent translocation of transducin through the photoreceptor cell connecting cilium

2006

Centrins are members of a highly conserved subgroup of the EF-hand superfamily of Ca(2+)-binding proteins commonly associated with centrosome-related structures. In the retina, centrins are also prominent components of the photoreceptor cell ciliary apparatus. Centrin isoforms are differentially localized at the basal body and in the lumen of the connecting cilium. All molecular exchanges between the inner and outer segments occur through this narrow connecting cilium. Ca(2+)-activated centrin isoforms bind to the visual heterotrimeric G-protein transducin via an interaction with the betagamma-subunit. Ca(2+)-dependent assemblies of centrin/G-protein complexes may regulate the transducin mo…

Differential Distribution of Harmonin Isoforms and Their Possible Role in Usher-1 Protein Complexes in Mammalian Photoreceptor Cells

2003

PURPOSE. Human Usher syndrome is the most common form of combined deafness and blindness. Usher type I (USH1), the most severe form, is characterized by profound congenital deafness, constant vestibular dysfunction, and prepubertal onset retinitis pigmentosa. Previous studies have shown that the USH1-proteins myosin VIIa, harmonin, and cadherin 23 interact and form a functional network during hair cell differentiation in the inner ear. The purpose of the present study was to analyze the molecular and cellular functions of these USH1 proteins in the mammalian retina. METHODS. Antibodies to USH1 proteins were generated and used in Western blot analysis of subcellular photoreceptor fractions a…

Centrins in retinal photoreceptor cells: regulators in the connecting cilium.

2008

Changes in the intracellular Ca2+ concentration regulate the visual signal transduction cascade directly or more often indirectly through Ca2+-binding proteins. Here we focus on centrins, which are members of a highly conserved subgroup of the EF-hand superfamily of Ca2+-binding proteins in photoreceptor cells of the vertebrate retina. Centrins are commonly associated with centrosome-related structures. In mammalian retinal photoreceptor cells, four centrin isoforms are expressed as prominent components in the connecting cilium linking the light-sensitive outer segment compartment with the metabolically active inner segment compartment. Our data indicate that Ca2+-activated centrin isoforms…

Bionate Lumbar Disc Nucleus Prosthesis: Biomechanical Studies in Cadaveric Human Spines.

2022

Design: cadaveric spine nucleus replacement study. Objective: determining Bionate 80A nucleus replacement biomechanics in cadaveric spines. Methods: in cold preserved spines, with ligaments and discs intact, and no muscles, L3-L4, L4-L5, and L5-S1 nucleus implantation was done. Differences between customized and overdimensioned implants were compared. Flexion, extension, lateral bending, and torsion were measured in the intact spine, nucleotomy, and nucleus implantation specimens. Increasing load or bending moment was applied four times at 2, 4, 6, and 8 Nm, twice in increasing mode and twice in decreasing mode. Spine motion was recorded using stereophotogrammetry. Expulsion tests: cyclic c…

The trilobite Serrodiscus Richter & Richter from Iberia, with systematic review of the genus and its international correlation through the Cambrian S…

2022

Serrodiscus is considered one of the first trilobite genera showing global distribution during the Cambrian and a key component for the international correlation of this period. However, this genus encompasses many poorly documented species, ambiguous diagnoses or characters that depend on taphonomy and deformation based on one single specimen. Thus, in the present work, we carry out a systematic overview of the genus, evaluating the taphonomic and deformational variability of a large number of specimens from the same locality and horizon. In addition, and due to the difficulty of making synonymy decisions, closely related species are grouped into three different groups taking into consider…

Grouping behaviour impacts on the parasitic pressure and squamation of sharks

2022

The evolution of grouping behaviour involves a complex trade-off of benefits and costs. Among the latter, an increase in the risk of parasitic transmission is a well-documented phenomenon that has likely promoted the evolution of defensive mechanisms in aquatic vertebrates. Here, we explore the relationship between grouping behaviour, parasitic richness (∼parasitic pressure), and the evolution of potential defensive traits in the squamation of sharks through phylogenetic, standard and zero-inflation regression models. Our results demonstrate that sharks that frequently aggregate show increased parasitic pressure, which may constitute an agent of selection. Accordingly, their squamation is c…

Post-mortem enamel surface texture alteration during taphonomic processes—do experimental approaches reflect natural phenomena?

2022

Experimental approaches are often used to better understand the mechanisms behindand consequences of post-mortem alteration on proxies for diet reconstruction.Dental microwear texture analysis (DMTA) is such a dietary proxy, using dental wearfeatures in extant and extinct taxa to reconstruct feeding behaviour and mechanicalfood properties. In fossil specimens especially, DMTA can be biased by post-mortemalteration caused by mechanical or chemical alteration of the enamel surface. Herewe performed three different dental surface alteration experiments to assess the effectof common taphonomic processes by simplifying them: (1) tumbling in sedimentsuspension to simulate fluvial transport, (2) s…

DNA barcode reference library for Iberian butterflies enables a continental-scale preview of potential cryptic diversity

2015

How common are cryptic species - those overlooked because of their morphological similarity? Despite its wide-ranging implications for biology and conservation, the answer remains open to debate. Butterflies constitute the best-studied invertebrates, playing a similar role as birds do in providing models for vertebrate biology. An accurate assessment of cryptic diversity in this emblematic group requires meticulous case-by-case assessments, but a preview to highlight cases of particular interest will help to direct future studies. We present a survey of mitochondrial genetic diversity for the butterfly fauna of the Iberian Peninsula with unprecedented resolution (3502 DNA barcodes for all 2…

Comment on “Controversies about Interspinous Process Devices in the Treatment of Degenerative Lumbar Spine Diseases: Past, Present, and Future”

2017

Association of Whirlin with Cav1.3 (α1D) Channels in Photoreceptors, Defining a Novel Member of the Usher Protein Network

2010

Contains fulltext : 88383.pdf (Publisher’s version ) (Closed access) PURPOSE: Usher syndrome is the most common form of hereditary deaf-blindness. It is both clinically and genetically heterogeneous. The USH2D protein whirlin interacts via its PDZ domains with other Usher-associated proteins containing a C-terminal type I PDZ-binding motif. These proteins co-localize with whirlin at the region of the connecting cilium and at the synapse of photoreceptor cells. This study was undertaken to identify novel, Usher syndrome-associated, interacting partners of whirlin and thereby obtain more insights into the function of whirlin. METHODS: The database of ciliary proteins was searched for proteins…