Tag and recapture of European hake (Merluccius merluccius L.) off the Northwest Iberian Peninsula: First results support fast growth hypothesis

Este es un artículo aceptado para publicación en Fisheries Research siguiendo revisión por pares. La versión definitiva puede consultarse en la web del editor.In the first tagging experiment of European hake (Merluccius merluccius L.) conducted off the NW Iberian Peninsula to study hake growth in the wild we released 527 live tagged individuals. The survival rate after capture and tagging was 58%. Mortality during capture was positively correlated with depth of capture and negatively correlated with hake size. Fifteen months after tagging, seven individuals (1.3%) had been recaptured with times at liberty ranging from 29 to 466 days. We provide the first direct measurements of growth rates of Southern stock European hake in the wild and compare them with rates obtained from tagging experiments in other regions and with rates derived from conventional otolith age reading. The mean somatic growth rate of all recaptured hake was 0.032 ± 0.016 cm day−1 (sexes combined), while the mean growth rate of the two hake with over 340 days at liberty was 0.052 ± 0.003 cm day−1 (sexes unknown). These results indicate that conventional otolith age reading methods overestimate age and underestimate growth

Growth of Northwest Iberian juvenile hake estimated by combining sagittal and transversal otolith microstructure analyses

Este es un artículo aceptado para publicación en Fisheries Research siguiendo revisión por pares. La versión definitiva puede consultarse en la web del editorDaily growth of Atlantic juvenile hake from Northwest Iberia has been estimated employing a new approach combining analyses of transversal and sagittal sections of the otoliths along the ventral radius. Age of juvenile hake ranging from 3 to 25 cm collected during a spring 2002 survey was estimated. Somatic growth followed a power fit: Fish size (TL) = 3.3254*age0.7336 (r2 = 0.87, p < 0.001, n = 76), yielding an average individual growth rate of 0.66 mm/day (±0.06). The growth model indicates that after a year's life a juvenile can reach 25 cm. Otolith ventral radius ranged from 401 to 1842 μm and daily increments were between 104 and 387. Fish growth and otolith growth were closely related (r2 = 0.92 p < 0.001, n = 76). These first results of daily growth rates for the Southern stock corroborate the fast-growth hypothesis of this species. The evolution of increment widths from hatch dates onwards reveals important seasonal growth peaks during July–August and October–November. A comparison with prior data and discussion is also presented in the light of recent work on hake juveniles and tagging-recapture experiences

Shedding Light on Fish Otolith Biomineralization Using a Bioenergetic Approach

Otoliths are biocalcified bodies connected to the sensory system in the inner ears of fish. Their layered, biorhythm-following formation provides individual records of the age, the individual history and the natural environment of extinct and living fish species. Such data are critical for ecosystem and fisheries monitoring. They however often lack validation and the poor understanding of biomineralization mechanisms has led to striking examples of misinterpretations and subsequent erroneous conclusions in fish ecology and fisheries management. Here we develop and validate a numerical model of otolith biomineralization. Based on a general bioenergetic theory, it disentangles the complex interplay between metabolic and temperature effects on biomineralization. This model resolves controversial issues and explains poorly understood observations of otolith formation. It represents a unique simulation tool to improve otolith interpretation and applications, and, beyond, to address the effects of both climate change and ocean acidification on other biomineralizing organisms such as corals and bivalves

A Mild Form of SLC29A3 Disorder: A Frameshift Deletion Leads to the Paradoxical Translation of an Otherwise Noncoding mRNA Splice Variant

We investigated two siblings with granulomatous histiocytosis prominent in the nasal area, mimicking rhinoscleroma and Rosai-Dorfman syndrome. Genome-wide linkage analysis and whole-exome sequencing identified a homozygous frameshift deletion in SLC29A3, which encodes human equilibrative nucleoside transporter-3 (hENT3). Germline mutations in SLC29A3 have been reported in rare patients with a wide range of overlapping clinical features and inherited disorders including H syndrome, pigmented hypertrichosis with insulin-dependent diabetes, and Faisalabad histiocytosis. With the exception of insulin-dependent diabetes and mild finger and toe contractures in one sibling, the two patients with nasal granulomatous histiocytosis studied here displayed none of the many SLC29A3-associated phenotypes. This mild clinical phenotype probably results from a remarkable genetic mechanism. The SLC29A3 frameshift deletion prevents the expression of the normally coding transcripts. It instead leads to the translation, expression, and function of an otherwise noncoding, out-of-frame mRNA splice variant lacking exon 3 that is eliminated by nonsense-mediated mRNA decay (NMD) in healthy individuals. The mutated isoform differs from the wild-type hENT3 by the modification of 20 residues in exon 2 and the removal of another 28 amino acids in exon 3, which include the second transmembrane domain. As a result, this new isoform displays some functional activity. This mechanism probably accounts for the narrow and mild clinical phenotype of the patients. This study highlights the ‘rescue’ role played by a normally noncoding mRNA splice variant of SLC29A3, uncovering a new mechanism by which frameshift mutations can be hypomorphic

Functional Diversity of Human Basic Helix-Loop-Helix Transcription Factor TCF4 Isoforms Generated by Alternative 5′ Exon Usage and Splicing

BACKGROUND: Transcription factor 4 (TCF4 alias ITF2, E2-2, ME2 or SEF2) is a ubiquitous class A basic helix-loop-helix protein that binds to E-box DNA sequences (CANNTG). While involved in the development and functioning of many different cell types, recent studies point to important roles for TCF4 in the nervous system. Specifically, human TCF4 gene is implicated in susceptibility to schizophrenia and TCF4 haploinsufficiency is the cause of the Pitt-Hopkins mental retardation syndrome. However, the structure, expression and coding potential of the human TCF4 gene have not been described in detail. PRINCIPAL FINDINGS: In the present study we used human tissue samples to characterize human TCF4 gene structure and TCF4 expression at mRNA and protein level. We report that although widely expressed, human TCF4 mRNA expression is particularly high in the brain. We demonstrate that usage of numerous 5' exons of the human TCF4 gene potentially yields in TCF4 protein isoforms with 18 different N-termini. In addition, the diversity of isoforms is increased by alternative splicing of several internal exons. For functional characterization of TCF4 isoforms, we overexpressed individual isoforms in cultured human cells. Our analysis revealed that subcellular distribution of TCF4 isoforms is differentially regulated: Some isoforms contain a bipartite nuclear localization signal and are exclusively nuclear, whereas distribution of other isoforms relies on heterodimerization partners. Furthermore, the ability of different TCF4 isoforms to regulate E-box controlled reporter gene transcription is varied depending on whether one or both of the two TCF4 transcription activation domains are present in the protein. Both TCF4 activation domains are able to activate transcription independently, but act synergistically in combination. CONCLUSIONS: Altogether, in this study we have described the inter-tissue variability of TCF4 expression in human and provided evidence about the functional diversity of the alternative TCF4 protein isoforms