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The aim of the present study was to establish a protocol for cryopreservation of sperm in Sparus aurata and also to verify the applicability under culture conditions. Cryopreservation of sperm was attempted by using two extenders: Extender A (10 % egg yolk, buffer solution) and Extender B (1 % NaCl, 10% BSA Bovine Serum Albumin). Cryoprotectants were assessed at three different concentrations (5, 10 and 15 %, DMSO) individually as well as in combination with varying equilibration times (10 and 30 min). In order to maintain freezing rate, freezing protocols were adjusted by - 30 °C/min intervals. Obtained results indicated that cryomedium constituting of Extender A with addition of 10% DMSO in dilution ratio of 1:3 (sperm:cryomedium) at an equilibration time of and freezing rate of - 30 °C/min was more desirable compared to the other experimental procedures (Extender B) that were assessed (P>0.05). Moreover, 40 °C for 10 s presented highest post-thaw motility after end of the first month (72, 7±0,35%) (P>0.05). Finally, it is determined that Extender A exhibited better performance in terms of sperm motility, freezing and thawing rate and also this ratio could be effectively utilized for cryopreservation of sperm for this species. [ABSTRACT FROM AUTHOR]

Transcription of ATP-binding cassette (ABC) transporters has been evaluated in cell lines and primary cultures from gilthead seabream and European sea bass teleost fish exposed to methylmercury (MeHg), arsenic, cadmium or lead. The mRNA expression levels showed abcb1 , abcc2 and abcc5 constitutive gene expression in all seabream tissues analyzed; however, we were unable to detect any constitutive transcription of abcb1 in many of the sea bass tissues. Furthermore, ABC mRNA expression levels were all affected by metal exposure, especially in the case of fish cell lines and erythrocytes, and greatly depended on cell type and fish species. Thus, while ABC transcription was up-regulated in the seabream cell line it was down-regulated in the sea bass cell line, while the opposite occurred in the primary cultures. All these data point to the importance of ABC transporters in metal detoxification and in the differential regulation in seabream and sea bass cells. [ABSTRACT FROM AUTHOR]

The development of Genotyping-By-Sequencing (GBS) technologies enables cost-effective analysis of large numbers of Single Nucleotide Polymorphisms (SNPs), especially in “non-model” species. Nevertheless, as such technologies enter a mature phase, biases and errors inherent to GBS are becoming evident. Here, we evaluated the performance of double digest Restriction enzyme Associated DNA (ddRAD) sequencing in SNP genotyping studies including high number of samples. Datasets of sequence data were generated from three marine teleost species (>5500 samples, >2.5 × 10 12 bases in total), using a standardized protocol. A common bioinformatics pipeline based on STACKS was established, with and without the use of a reference genome. We performed analyses throughout the production and analysis of ddRAD data in order to explore (i) the loss of information due to heterogeneous raw read number across samples; (ii) the discrepancy between expected and observed tag length and coverage; (iii) the performances of reference based vs. de novo approaches; (iv) the sources of potential genotyping errors of the library preparation/bioinformatics protocol, by comparing technical replicates. Our results showed use of a reference genome and a posteriori genotype correction improved genotyping precision. Individual read coverage was a key variable for reproducibility; variance in sequencing depth between loci in the same individual was also identified as an important factor and found to correlate to tag length. A comparison of downstream analysis carried out with ddRAD vs single SNP allele specific assay genotypes provided information about the levels of genotyping imprecision that can have a significant impact on allele frequency estimations and population assignment. The results and insights presented here will help to select and improve approaches to the analysis of large datasets based on RAD-like methodologies. [ABSTRACT FROM AUTHOR]

Fish is one of the most valuable protein sources and vulnerable to all environmental pollution including metals. Metals play vital roles in enzyme activities and other metabolic events with their bioaccumulative and nonbiodegradable properties among aquatic pollutants. Metal toxicity causes irregular metallothioneins protein synthesis, renal damage, and disruption of bone structure in humans and wildlife. In this study, we investigated in vitro effects of some metal ions on chemical-targeted glucose 6- phosphate dehydrogenase (G6PD; EC 1.1.1.49) enzyme from gilthead sea bream (Sparus aurata) liver and gill tissues. In this purpose, G6PD was purified from gilthead sea bream liver and gill. The purification was performed by preparation of homogenates, ammonium sulphat precipitation and 2',5'-ADP Sepharose 4B affinity chromatography. Overall purification procedure, yield and purification fold for liver and gill were obtained as 54.6%, 52.2% and 1864.3, 283, respectively. The purify of the enzymes were checked by SDS-PAGE. Which shaved a single band. Additionally, inhibitory effects of some metal ions (Zn2+, Ni2+, Cd2+, Ag+, Cu2+ and Al3+) were ex-amined the enzyme's activity in vitro by performing Lineweaver-Burk graphs and plotting activity% vs., respectively. [ABSTRACT FROM AUTHOR]

The presence of organochlorine pesticides and polychlorinated biphenyls in wild and farmed gilthead sea bream (Sparus aurata) from the Western Mediterranean, Spain, is investigated. These pollutants were determined in white and red muscle and liver by gas chromatography coupled to tandem mass spectrometry. Contaminant profiles present in both wild and farmed fish tissues include DDTs, PCBs and HCB. The highest concentrations of contaminants were found in liver, and an increase in pollutant levels was observed in autumn, before spawning. This fact is explained in light of increased food intake when sea water temperatures increase. Gilthead sea bream from Western Mediterranean populations showed significantly higher concentrations of DDTs and PCBs than farmed fish from the same area. This fact is attributed to the low level of organochlorine contaminants present in fish feed supplied to the cultured fish. The diet is highlighted as an important factor in understanding differences observed in organochlorine pollutants levels of fish tissues. [Copyright &y& Elsevier]