Low microsatellite variation in Aphanius fasciatus from the Tarquinia Salterns

1 - The Tarquinia Salterns (Latium, central Italy) provided the opportunity to analyse the impact of environmental stress on the genetic structure of the resident population of the killifish Aphanius fasciatus. Indeed, after the salt production ceased in 1997, the salterns have undergone habitat degradation due to lack of maintenance. The ecological restoration carried out from 2003 to 2006 reverted the environmental conditions to those of ten years before. 2 - The temporal variation of the gene pool of the population of A. fasciatus inhabiting the Tarquinia Salterns was investigated using microsatellite markers in samples collected in 1998 and 2003. The results obtained showed a low genetic variability and a genetic homogeneity of the population, which appears not divided in sub-demes. 3 - Microsatellites revealed a surprisingly low level of genetic variability when compared to allozyme data obtained in previous studies. This is likely due to a difference in the time of response of the two markers to environmental degradation. Microsatellites would lose genetic variability earlier and faster because of their usually high polymorphisms. Conversely, allozymes would be more resistant to genetic erosion, being moderately variable markers. 4 - Selection probably contributed in maintaining allozyme polymorphism, while microsatellites, being neutral markers, did not benefit from the action of selection and lost diversity earlier and more rapidly. Accordingly, the population appeared subdivided in distinct demes based on allozyme data but spatially homogeneous following microsatellites results

The Application of DNA Barcodes for the Identification of Marine Crustaceans from the North Sea and Adjacent Regions

During the last years DNA barcoding has become a popular method of choice for molecular specimen identification. Here we present a comprehensive DNA barcode library of various crustacean taxa found in the North Sea, one of the most extensively studied marine regions of the world. Our data set includes 1,332 barcodes covering 205 species, including taxa of the Amphipoda, Copepoda, Decapoda, Isopoda, Thecostraca, and others. This dataset represents the most extensive DNA barcode library of the Crustacea in terms of species number to date. By using the Barcode of Life Data Systems (BOLD), unique BINs were identified for 198 (96.6%) of the analyzed species. Six species were characterized by two BINs (2.9%), and three BINs were found for the amphipod species Gammarus salinus Spooner, 1947 (0.4%). Intraspecific distances with values higher than 2.2% were revealed for 13 species (6.3%). Exceptionally high distances of up to 14.87% between two distinct but monophyletic clusters were found for the parasitic copepod Caligus elongatus Nordmann, 1832, supporting the results of previous studies that indicated the existence of an overlooked sea louse species. In contrast to these high distances, haplotype-sharing was observed for two decapod spider crab species, Macropodia parva Van Noort & Adema, 1985 and Macropodia rostrata (Linnaeus, 1761), underlining the need for a taxonomic revision of both species. Summarizing the results, our study confirms the application of DNA barcodes as highly effective identification system for the analyzed marine crustaceans of the North Sea and represents an important milestone for modern biodiversity assessment studies using barcode sequence

Proteostasis regulators modulate proteasomal activity and gene expression to attenuate multiple phenotypes in Fabry disease

The lysosomal storage disorder Fabry disease is characterized by a deficiency of the lysosomal enzyme \u3b1-Galactosidase A. The observation that missense variants in the encoding GLA gene often lead to structural destabilization, endoplasmic reticulum retention and proteasomal degradation of the misfolded, but otherwise catalytically functional enzyme has resulted in the exploration of alternative therapeutic approaches. In this context, we have investigated proteostasis regulators (PRs) for their potential to increase cellular enzyme activity, and to reduce the disease-specific accumulation of the biomarker globotriaosylsphingosine in patient-derived cell culture. The PRs also acted synergistically with the clinically approved 1-deoxygalactonojirimycine, demonstrating the potential of combination treatment in a therapeutic application. Extensive characterization of the effective PRs revealed inhibition of the proteasome and elevation of GLA gene expression as paramount effects. Further analysis of transcriptional patterns of the PRs exposed a variety of genes involved in proteostasis as potential modulators. We propose that addressing proteostasis is an effective approach to discover new therapeutic targets for diseases involving folding and trafficking-deficient protein mutants

Genetic Structure of Bluefin Tuna in the Mediterranean Sea Correlates with Environmental Variables

Abstract Background Atlantic Bluefin Tuna (ABFT) shows complex demography and ecological variation in the Mediterranean Sea. Genetic surveys have detected significant, although weak, signals of population structuring; catch series analyses and tagging programs identified complex ABFT spatial dynamics and migration patterns. Here, we tested the hypothesis that the genetic structure of the ABFT in the Mediterranean is correlated with mean surface temperature and salinity. Methodology We used six samples collected from Western and Central Mediterranean integrated with a new sample collected from the recently identified easternmost reproductive area of Levantine Sea. To assess population structure in the Mediterranean we used a multidisciplinary framework combining classical population genetics, spatial and Bayesian clustering methods and a multivariate approach based on factor analysis. Conclusions FST analysis and Bayesian clustering methods detected several subpopulations in the Mediterranean, a result also supported by multivariate analyses. In addition, we identified significant correlations of genetic diversity with mean salinity and surface temperature values revealing that ABFT is genetically structured along two environmental gradients. These results suggest that a preference for some spawning habitat conditions could contribute to shape ABFT genetic structuring in the Mediterranean. However, further studies should be performed to assess to what extent ABFT spawning behaviour in the Mediterranean Sea can be affected by environmental variation.(undefined

Phylogeography of Sardinian Cave Salamanders (Genus Hydromantes) Is Mainly Determined by Geomorphology

Detecting the factors that determine the interruption of gene flow between populations is key to understanding how speciation occurs. In this context, caves are an excellent system for studying processes of colonization, differentiation and speciation, since they represent discrete geographical units often with known geological histories. Here, we asked whether discontinuous calcareous areas and cave systems represent major barriers to gene flow within and among the five species of Sardinian cave salamanders (genus Hydromantes) and whether intraspecific genetic structure parallels geographic distance within and among caves. We generated mitochondrial cytochrome b gene sequences from 184 individuals representing 48 populations, and used a Bayesian phylogeographic approach to infer possible areas of cladogenesis for these species and reconstruct historical and current dispersal routes among distinct populations. Our results show deep genetic divergence within and among all Sardinian cave salamander species, which can mostly be attributed to the effects of mountains and discontinuities in major calcareous areas and cave systems acting as barriers to gene flow. While these salamander species can also occur outside caves, our results indicate that there is a very poor dispersal of these species between separate cave systems

Large-Scale Spatio-Temporal Patterns of Mediterranean Cephalopod Diversity

Species diversity is widely recognized as an important trait of ecosystems’ functioning and resilience. Understanding the causes of diversity patterns and their interaction with the environmental conditions is essential in order to effectively assess and preserve existing diversity. While diversity patterns of most recurrent groups such as fish are commonly studied, other important taxa such as cephalopods have received less attention. In this work we present spatio-temporal trends of cephalopod diversity across the entire Mediterranean Sea during the last 19 years, analysing data from the annual bottom trawl survey MEDITS conducted by 5 different Mediterranean countries using standardized gears and sampling protocols. The influence of local and regional environmental variability in different Mediterranean regions is analysed applying generalized additive models, using species richness and the Shannon Wiener index as diversity descriptors. While the western basin showed a high diversity, our analyses do not support a steady eastward decrease of diversity as proposed in some previous studies. Instead, high Shannon diversity was also found in the Adriatic and Aegean Seas, and high species richness in the eastern Ionian Sea. Overall diversity did not show any consistent trend over the last two decades. Except in the Adriatic Sea, diversity showed a hump-shaped trend with depth in all regions, being highest between 200–400 m depth. Our results indicate that high Chlorophyll a concentrations and warmer temperatures seem to enhance species diversity, and the influence of these parameters is stronger for richness than for Shannon diversityVersión del editor4,411

Development of microfluidic devices to maintain and interrogate tissue biopsies : biomedical applications

Currently most cell-based methodologies in microfluidic systems utilize homogeneous or heterogeneous cell populations. However, these systems do not present an accurate representation of in vivo dynamics. A microfluidic based experimental methodology has been developed that offers a biomimetic microenvironment in which pseudo in vivo tissue studies can be carried out under in vitro conditions. Using this innovative technique, which utilizes the inherent advantages of microfluidic technology, liver and cancer tissue have been kept in a viable and functional state for over seven days. Biochemical assays, histological examination, confocal imaging, epi-fluorescent microscopy were all performed to assess the viability of the tissue before and after interrogation by several apoptosis inducing and chemotherapeutic agents. Liver tissue samples were also disaggregated in situ on-chip into individual primary cells, using a collagenase digestion procedure, enabling further cell analysis to be carried out off-line. Cancer tissue was probed with chemotherapeutic drugs for the analysis of apoptotic biomarkers such as cytochrome c, nucleosomes and DMA that were found to be representative of previous published clinical results. It is anticipated that this methodology will have a wide impact on biological and clinical research in fields such as cancer prognosis and treatment, drug development and toxicity, as well as enabling better fundamental research into tissue/cell processes.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Thirty years of artificial syntopy between Hydromantes italicus and H. ambrosii ambrosii (Amphibia, Plethodontidae)

Thirty years ago, in 1983, an experiment of artificial syntopy put together two allopatric taxa of mainland European plethodontids: Hydromantes ambrosii ambrosii and H. italicus. An equal number of specimens of both species were released in a cave with a suitable environment but located outside the range of the genus. The aim was to test the effectiveness of the reproductive isolating mechanisms of these two moderately divergent taxa and, in the case hybridization would have occurred, to analyse the extent and mechanisms of introgressive hybridization while in progress. Previous data collected between 1996 and 1999 showed that H. italicus and H. a. ambrosii were hybridizing and that their hybrids were viable and fertile enough to produce backcrosses. The data presented here, based on allozymes and restriction enzymes on a fragment of the mitochondrial Cytochrome-b gene, showed that introgressive hybridization is still ongoing. However, the gene exchange between the two taxa is restricted since most of the specimens scored were pure H. a. ambrosii, the percentage of hybrid/recombinant specimens was quite low and a strong deficiency of heterozygote genotypes was recorded. The results presented showed that this long term experiment assisted in providing insights into the patterns and mechanisms underlying hybridization and introgression, showing the spreading of a foreign mtDNA (H. italicus) into the gene pool of another species (H. a. ambrosii) despite the fact that the nuclear genomes remain substantially differentiated.</jats:p