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Reykjavík, Iceland

Hreggvidsson G.O.,Matis Ltd. | Hreggvidsson G.O.,University of Iceland | Dobruchowska J.M.,University Utrecht | Fridjonsson O.H.,University of Iceland | And 7 more authors.
Glycobiology | Year: 2011

Over the years several β-glucan transferases from yeast and fungi have been reported, but enzymes with such an activity from bacteria have not been characterized so far. In this work, we describe the cloning and expression of genes encoding β-glucosyltransferase domains of glycosyl hydrolase family GH17 from three species of proteobacteria: Pseudomonas aeruginosa PAO1, P. putida KT2440 and Azotobacter vinelandii ATCC BAA-1303. The encoded enzymes of these GH17 domains turned out to have a non-Leloir trans-β-glucosylation activity, as they do not use activated nucleotide sugar as donor, but transfer a glycosyl group from a β-glucan donor to a β-glucan acceptor. More particularly, the activity of the three recombinant enzymes on linear (β1→3)-linked gluco-oligosaccharides (Lam-Glc 4-9) and their corresponding alditols (Lam-Glc 4- 9-ol) was studied. Detailed structural analysis, based on thin-layer chromatography, matrix-assisted laser desorption ionization time-of-flight mass spectrometry, electrospray ionization mass spectrometry, and 1D/2D 1H and 13C nuclear magnetic resonance data, revealed diverse product spectra. Depending on the enzyme used, besides (β1→3)-elongation activity, (β1→4)- or (β1→6)- elongation, or (β1→6)-branching activities were also detected. © 2010 The Author. Source

Gudmundsson L.A.,Institute of Freshwater Fisheries | Gudjonsson S.,Institute of Freshwater Fisheries | Marteinsdottir G.,University of Iceland | Scarnecchia D.L.,University of Idaho | And 3 more authors.
Conservation Genetics | Year: 2013

Although the tendency of Atlantic salmon Salmo salar to form differentiated populations among rivers and among tributaries within large river systems (>100 km-long) is well documented, much less is known about population structure within small river systems (<30 km-long). In the present study, we investigated the genetic effects of straying of hatchery-reared salmon on population structure and genetic composition within the Ellidaár river system, a small system (21 km total length) in SW Iceland. We analyzed spatial and temporal variation of wild and domesticated samples (farmed and ranched; n = 931) using seven microsatellite loci. Estimates of population differentiation [FST, genetic tree (DA)] and Bayesian cluster analysis (STRUCTURE) revealed a significant population structure as well as relative long-term temporal stability of the genetic composition in the main river from 1948 to 2005. However, the genetic composition of the tributary populations was unstable and genetically homogenized in recent years. Wild-hatchery hybrids were detected during the influx of strays as well as few years after, suggesting that introgression has changed the genetic composition of the wild populations. More investigations are needed in Iceland and elsewhere on possible fine-scale population differentiation and factors leading to it. Fine-scale population differentiation as observed in the present study has implications for the resolution with which harvest and habitat management of salmon should be conducted. In addition, farming and ranching operations should be located to minimize potential negative effects of strays on wild fish. © 2013 Springer Science+Business Media Dordrecht. Source

Jorundsdottir H.,University of Stockholm | Jorundsdottir H.,Matis Ltd. | Lofstrand K.,University of Stockholm | Svavarsson J.,University of Iceland | And 2 more authors.
Chemosphere | Year: 2013

Data on distribution, concentration and trends of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) is scarce in biota from the sub-Arctic region of the Atlantic. The present study is an investigation on PBDE and HBCD concentrations in eggs from seven marine bird species from Iceland, i.e. common eider (Somateria mollissima), arctic tern (Sterna paradisaea), guillemot (Uria aalge), fulmar (Fulmarus glacialis), lesser black-backed gull (Larus fuscus), great black-backed gull (Larus marinus) and great skua (Stercorarius skua). Concentrations of sum PBDEs ranged from 44ngg-1fat in eider eggs to 2400ngg-1fat in great skua eggs. The contribution of different PBDE congeners to the sum concentration differed between species. Concentration of HBCDs (sum of α-,β- and γ-HBCD) ranged from 1.3ngg-1fat in arctic tern eggs to 41ngg-1fat in great black-backed gull. PCA on PBDE and HBCD shows different trends between the two BFR groups, further indicating different sources/usage. Investigations on any potential health or population effects of environmental pollutants on the great skua are advised since both the PBDE and HBCD concentrations are high. © 2013 Elsevier Ltd. Source

Bjornsson H.,University of Iceland | Marteinsson V.P.,Matis Ltd. | Fridjonsson O.,Matis Ltd. | Linke D.,Max Planck Institute for Developmental Biology | Benediktsdottir E.,University of Iceland
Journal of Applied Microbiology | Year: 2011

Aims: Moritella viscosa is a Gram-negative psychrophilic bacterium that causes winter ulcer disease in farmed fish. The aim of the study was to describe an outer membrane protein of roughly 20kDa in pathogenic M. viscosa and to compare the coincident protein of strains isolated from different fish species and geographical locations. Methods and Results: The protein was isolated from a pathogenic strain of M. viscosa. An oligopeptide sequence obtained with MS/MS analysis showed homology to Escherichia coli OmpA and Neisseria surface protein A. The protein was named Moritella viscosa outer membrane protein 1 (MvOmp1), and sequence analysis confirmed that it is an integral membrane protein consisting of eight antiparallel β-strands, three short periplasmic turns and four long hydrophilic extracellular loops. The encoding gene, mvomp1, was fully sequenced in nine strains representing different serotypes and phenotypes. The results revealed some differences in the extracellular loops between strains. The mvomp1 gene was cloned and expressed in E. coli, and the recombinant product was recognized by anti-M. viscosa polyclonal antisera. Conclusions: The results indicate that MvOmp1 is a major protective antigen of M. viscosa. Significance and Impact of the Study: The results open up possibilities for use of the protein as a part of a subunit vaccine in the future. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology. Source

Olafsson K.,University of Iceland | Olafsson K.,Matis Ltd. | Pampoulie C.,Iceland Marine Research Institute | Hjorleifsdottir S.,Matis Ltd. | And 3 more authors.
PLoS ONE | Year: 2014

Due to an improved understanding of past climatological conditions, it has now become possible to study the potential concordance between former climatological models and present-day genetic structure. Genetic variability was assessed in 26 samples from different rivers of Atlantic salmon in Iceland (total of 2,352 individuals), using 15 microsatellite loci. F-statistics revealed significant differences between the majority of the populations that were sampled. Bayesian cluster analyses using both prior information and no prior information on sampling location revealed the presence of two distinguishable genetic pools - namely, the Northern (Group 1) and Southern (Group 2) regions of Iceland. Furthermore, the random permutation of different allele sizes among allelic states revealed a significant mutational component to the genetic differentiation at four microsatellite loci (SsaD144, Ssa171, SSsp2201 and SsaF3), and supported the proposition of a historical origin behind the observed variation. The estimated time of divergence, using two different ABC methods, suggested that the observed genetic pattern originated from between the Last Glacial Maximum to the Younger Dryas, which serves as additional evidence of the relative immaturity of Icelandic fish populations, on account of the recolonisation of this young environment following the Last Glacial Maximum. Additional analyses suggested the presence of several genetic entities which were likely to originate from the original groups detected. © 2014 Olafsson et al. Source

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