Are farmed European seabass (Dicentrarchus labrax) prices in European Union markets affected by Turkish exports of farmed European seabass?

Abstract

Often, increases in farmed seabass and seabream production surpluses from Turkey and Greece have been blamed to lead to price declines and aquaculture sector crises. In this study, we investigate whether Turkish exports of farmed European seabass affect prices of European Union (EU) farmed European seabass. This is done by examining the existence of market integration between the prices of Turkish exports of farmed European seabass into the EU and the prices of farmed European seabass commercialized in wholesale markets in Barcelona, Madrid and Paris. Market integration and competition studies in fisheries and aquaculture products have generally focused on analyzing substitutability between species and between wild and farmed conspecifics. Few studies have focused on analyzing market integration between different geographic areas. Market integration analyses between different geographic areas have proven useful in anti-dumping investigations. Results show the lack of market integration between EU imports of Turkish farmed European seabass and main EU wholesale markets; in other words, farmed European seabass prices in EU markets do not seem to be affected by export prices of Turkish farmed seabass.     

Application of host-specific genetic markers for microbial source tracking of faecal water contamination in an agricultural catchment

Elevated nutrient concentrations in streams in the Norwegian agricultural landscape may occur due to faecal contamination. Escherichia coli (E. coli) has been used conventionally as an indicator of this contamination; however, it does not indicate the source of faecal origin. This work describes a study undertaken for the first time in Norway on an application of specific host-associated markers for faecal source tracking of water contamination. Real-time quantitative polymerase chain reaction (qPCR) on Bacteroidales host-specific markers was employed for microbial source tracking (MST) to determine the origin(s) of faecal water contamination. Four genetic markers were used: the universal AllBac (Bacteroidales) and the individual specific markers BacH (humans), BacR (ruminants) and Hor-Bac (horses). In addition, a pathogenicity test was carried out to detect the top seven Shiga toxin-producing E. coli (STEC) serogroups. The ratio between each individual marker and the universal one was used to: (1) normalise the markers to the level of AllBac in faeces, (2) determine the relative abundance of each specific marker, (3) develop a contribution profile for faecal water contamination and (4) elucidate the sources of contamination by highlighting the dominant origin(s). The results of the qPCR MST analyses indicated the actual contributions of humans and animals to faecal water contamination. The pathogenicity test revealed that water samples were STEC positive at a low level, which was in proportion to the concentration of the ruminant marker. The outcomes were verified statistically by coupling the findings of major contamination sources with observations in the field regarding local land use (residential or agricultural). Furthermore, clear correlations between the human marker and E. coli counts as well as the ruminant marker and STEC quantity in faecally contaminated water were observed. The results of this study have the potential to help identify sources of pollution for targeted mitigation of nutrient losses.     

Interaction of low density lipoproteins with liver cells in rainbow trout

Liver is the main catabolic tissue for low density lipoprotein in rainbow trout (Gjøen and Berg 1992). We have investigated the interaction of LDL with isolated trout liver cells and liver membranes. ¹²⁵I-TC labelled trout LDL bound to isolated trout liver cells in a time dependent and saturable manner with an apparant K_d of 20.1 g/ml, suggesting the existence of a specific binding site on the surface of these cells. The binding was Ca²⁺ dependent assessed by the 50% reduction obtained by 5 mM EDTA. Saturable binding to isolated trout liver membranes could also be demonstrated, but with lower affinity as compared to intact cells. Degradation of ¹²⁵I-TC-LDL in hepatocytes was also saturable as degradation could be inhibited about 60% by a 100 fold surplus of unlabelled LDL. The rate of degradation increased with temperature up to 20°C. Both cell association (binding + uptake) and degradation were reduced down to 20% of control in the presence of microtubular and lysosomal inhibitors. Hepatic catabolism of trout LDL therefore seems to depend on receptormediated endocytosis, followed by lysosomal degradation.Abbreviations TC tyramine cellobiose - LDL low density lipoproteins - MeLDL methylated low density lipoproteins - VLDL very low density lipoproteins - HDL high density lipoproteins - VTG vitellogenin - EDTA ethylenediamine tetraacetic acid - PBS phospate buffered saline - SDS-PAGE sodium dodecyl sulphatepolyacrylamide gel electrophoresis - DMPC L--phosphatidylcholine-dimyristoyl     

Effects of cattle slurry and cultivation on infiltration in sandy and silty soils from northern Norway

The study was conducted on virgin (uncultivated) and cultivated bare sandy and silty soil monoliths to investigate the infiltration rate before and after application of cattle slurry. Both soils had higher infiltration rates in the virgin state than in the cultivated state. Application of either 50 Mg ha⁻¹ fresh or aerated slurry to the soil surface caused a significant decrease in infiltration rate which lasted for 3 months. No significant difference in infiltration rate was found between fresh and aerated slurry. The application of slurry decreased the infiltration rate most on the virgin sandy soil. Only a small decrease was recorded, owing its to low initial infiltration rate on the cultivated silty soil. The infiltration rate before slurry application was positively correlated with air-filled porosity at −5 kPa matric potential and negatively correlated with soil on ignition. After slurry application the infiltration rate was positively correlated with soil air-filled porosity and negatively correlated with slurry dry matter content.     

Violacein-Producing Collimonas sp. from the Sea Surface Microlayer of Costal Waters in Tr?ndelag,Norway

A new strain belonging to the genus Collimonas was isolated from the sea surface microlayer off the coast of Trøndelag, Norway. The bacterium, designated Collimonas CT, produced an antibacterial compound active against Micrococcus luteus. Subsequent studies using LC-MS identified this antibacterial compound as violacein, known to be produced by several marine-derived bacteria. Fragments of the violacein biosynthesis genes vioA and vioB were amplified by PCR from the Collimonas CT genome and sequenced. Phylogenetic analysis of these sequences demonstrated close relatedness of the Collimonas CT violacein biosynthetic gene cluster to those in Janthinobacterium lividum and Duganella sp., suggesting relatively recent horizontal gene transfer. Considering diverse biological activities of violacein, Collimonas CT shall be further studied as a potential producer of this compound.