Metabolism of low density lipoproteins in rainbow trout     

Tor Gjøen  Trond Berg 《Fish physiology and biochemistry》1992,9(5-6):453-461

Plasma kinetics and tissue sites of degradation for native and chemically modified low density lipoproteins have been investigated in (Oncorhynchus mykiss). Native and modified LDL labelled with¹²⁵I-tyramine-cellobiose, (a residualizing adduct), were injected intravenously, and plasma and organ samples analyzed. Native LDL were cleared with a half life of about 30 hours, and mainly catabolized in the liver. Acetylation of LDL resulted in accelerated clearance (t_1/2=2 h) and catabolism in the kidneys. Methylation of LDL had only minor effects on catabolism. The cellular localization of lipoprotein uptake was visualized in kidney by fluorescence microscopy. Native LDL were endocytozed by spheroid, parenchymal cells, supposedly steroid-producing cells. Acetylated, fluorescent LDL were found in vacuoles of flattened, sinusoidal lining endothelial cells. Our data show that catabolism of native low density lipoproteins in salmonids takes place mainly via hepatic receptors. A scavenger receptor pathway, for modified lipoproteins (mainly localized in the kidney) is also operative in trout.  相似文献   

Peat replacement in horticultural growth media: the adequacy of coir,paper sludge and biogas digestate as growth medium constituents for tomato (Solanum lycopersicum L.) and lettuce (Lactuca sativa L.)     

Astrid Solvåg Nesse  Trine Sogn  Trond Børresen  Bente Foereid 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2019,69(4):287-294

Purpose: Due to environmental concerns, efforts are made to replace the use of peat in horticultural growth media by organic wastes. Four growth media were prepared with the purpose of achieving adequate physical and chemical properties for plant production. Materials and methods: Growth media prepared from mixtures of coir (C) and paper sludge (P), respectively, with two biogas digestates from food waste (D₁ and D₂), were tested. These mixtures, 20% D₁ or D₂?+?80% C or P (v/v), were evaluated as growth media for tomato (Solanum lycopersicum L.) and lettuce (Lactuca sativa L.). Results and conclusion: The growth media were all physically stable during the growing period, provided all the macronutrients and most of the micronutrients necessary for plant growth, adequate pH conditions, as well as an adequate electrical conductivity. The mixture of D₂ and P produced the highest biomass compared to a mineral fertilised peat (control), with a biomass production of 76% of the control for lettuce and 54% for tomato. Causes for the biomass reduction relative to the control may be related to ammonium toxicity effects, and/or limited plant-available water. The digestates, particularly D₁, seemed also to have a phytotoxic effect on the germination.  相似文献   

Pacific cod in the Anthropocene: An early life history perspective under changing thermal habitats     

Benjamin J. Laurel  Alisa Abookire  Steve J. Barbeaux  L. Zoe Almeida  Louise A. Copeman  Janet Duffy-Anderson  Thomas P. Hurst  Michael A. Litzow  Trond Kristiansen  Jessica A. Miller  Wayne Palsson  Sean Rooney  Hillary L. Thalmann  Lauren A. Rogers 《Fish and Fisheries》2023,24(6):959-978

The rapid decline in Pacific cod (Gadus macrocephalus, Gadidae) biomass following multiple Gulf of Alaska marine heatwaves (2014–2016 and 2019) may be one of the most dramatic documented changes in a sustainably managed marine fishery. As such, fisheries managers are exploring new recruitment paradigms for Pacific cod under novel environmental conditions. In this review, we address the challenges of managing and forecasting Pacific cod populations in the Eastern Pacific where thermal habitats for early life stages are undergoing varying rates of change across space and time. We use observational data to examine changes in distribution, abundance and demographics of the population from 1993 to 2020, and model contemporary and future changes of thermal habitat for both spawning success and age-0 juvenile growth potential. Results indicate that reduced spawning habitat and early life stage abundance may be a precursor to regional population decline, but the recent apparent increases in size-at-age of pre-recruits will have unknown impacts on future recruitment in these regions. We contend that continued monitoring of early life stages will be necessary to track changes in phenology and growth that likely determine size-at-age and the survival trajectories of year classes into the adult population. These include complex size- and temperature-dependent energetics spanning seasonal habitats through the first winter. Climate-ready management of Pacific cod will, therefore, require new process investigations beyond single-season surveys focused on one-life stage.  相似文献   

How pathogens affect the marine habitat use and migration of sea trout (Salmo trutta) in two Norwegian fjord systems     

Robert J. Lennox  Sindre H. Eldøy  Knut W. Vollset  Kristi M. Miller  Shaorong Li  Karia H. Kaukinen  Trond E. Isaksen  Jan G. Davidsen 《Journal of fish diseases》2020,43(7):729-746

Wild fish are confronting changing pathogen dynamics arising from anthropogenic disturbance and climate change. Pathogens can influence animal behaviour and life histories, yet there are little such data from fish in the high north where pathogen dynamics may differ from comparatively southern regions. We aimed to compare the pathogen communities of 160 wild anadromous brown trout in two fjords in northern Norway and to determine whether pathogens influenced area use or return to spawn. Application of high-throughput qPCR detected 11 of the 46 pathogens screened for; most frequently encountered were Ichthyobodo spp., Flavobacterium psychrophilum and Candidatus Branchiomonas cysticola. The rate of returning to freshwater during the spawning season was significantly lower for the Skjerstadfjord fish. Piscichlamydia salmonis and F. psychrophilum were indicator species for the Skjerstadfjord and pathogen communities in the two fjords differed according to perMANOVA. Individual length, Fulton's condition factor and the time between first and last detection of the fish were not related to the presence of pathogens ordinated using non-metric multidimensional scaling (NMDS). However, there was evidence that pathogen load was correlated with the expression of smoltification genes, which are upregulated by salmonids in freshwater. Correspondingly, percentage of time in freshwater after release was longer for fish with greater pathogen burdens.  相似文献   

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

Trond Bjørndal  Jordi Guillen  Ferit Rad 《Aquaculture Economics & Management (Blackwell Science)》2019,23(3):341-357

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.  相似文献   

Characterization of Streptomyces spp. Isolated from the Sea Surface Microlayer in the Trondheim Fjord, Norway          下载免费PDF全文

Sigrid Hakvg  Espen Fjrvik  Kjell D. Josefsen  Elena Ian  Trond E. Ellingsen    Sergey B. Zotchev 《Marine drugs》2008,6(4):620-635

The water surface microlayer is still poorly explored, although it has been shown to contain a high density of metabolically active bacteria, often called bacterioneuston. Actinomycetes from the surface microlayer in the Trondheim fjord, Norway, have been isolated and characterized. A total of 217 isolates from two separate samples morphologically resembling the genus Streptomyces have been further investigated in this study. Antimicrobial assays showed that about 80% of the isolates exhibited antagonistic activity against non-filamentous fungus, Gram-negative, and Gram-positive bacteria. Based on the macroscopic analyses and inhibition patterns from the antimicrobial assays, the sub-grouping of isolates was performed. Partial 16S rDNAs from the candidates from each subgroup were sequenced and phylogenetic analysis performed. 7 isolates with identical 16S rDNA sequences were further studied for the presence of PKS type I genes. Sequencing and phylogenetic analysis of the PKS gene fragments revealed that horizontal gene transfer between closely related species might have taken place. Identification of unique PKS genes in these isolates implies that de-replication can not be performed based solely on the 16S rDNA sequences. The results obtained in this study suggest that streptomycetes from the neuston population may be an interesting source for discovery of new antimicrobial agents.  相似文献   

Evaluation of nonstarch polysaccharides and oligosaccharide content of different soybean varieties (Glycine max) by near-infrared spectroscopy and proteomics     

Hollung K  Øverland M  Hrustić M  Sekulić P  Miladinović J  Martens H  Narum B  Sahlstrøm S  Sørensen M  Storebakken T  Skrede A 《Journal of agricultural and food chemistry》2005,53(23):9112-9121

A total of 832 samples of soybeans were screened by near-infrared (NIR) reflectance spectroscopy, to identify soybean samples with a lower content of oligosaccharides and nonstarch polysaccharides (NSP). Of these, 38 samples were identified on the basis of variation in protein content and agronomic value and submitted to high-resolution NIR spectroscopy. On the basis of the NIR data, 12 samples were further selected for chromatographic characterization of carbohydrate composition (mono-, di-, and oligosaccharides and NSP). Their soluble proteins were separated by two-dimensional gel electrophoresis (2DE). Using partial least-squares regression (PLSR), it was possible to predict the content of total NSP from the high-resolution NIR spectra, suggesting that NIR is a suitable and rapid nondestructive method to determine carbohydrate composition in soybeans. The 2DE analyses showed varying intensities of several proteins, including the glycinin G1 precursor. PLSR analysis showed a negative correlation between this protein and insoluble NSP and total uronic acid (UA).  相似文献   

Repeated use of green-manure catch crops in organic cereal production – grain yields and nitrogen supply     

Anne-Kristin Løes  Trond M. Henriksen  Ragnar Eltun  Helge Sjursen 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(2):164-175

Abstract

By restricted access to manure, nitrogen (N) supply in organic agriculture relies on biological N-fixation. This study compares grain yields after one full-season green manure (FSGM) to yields with repeated use of a green-manure catch crop. At two sites in south-eastern Norway, in a simple 4-year rotation (oats/wheat/oats/wheat), the repeated use of ryegrass, clover, or a mixture of ryegrass and clover as catch crops was compared with an FSGM established as a catch crop in year 1. The FSGM treatments had no subsequent catch crops. In year 5, the final residual effects were measured in barley.

The yield levels were about equal for grains with no catch crop and a ryegrass catch crop. On average, the green-manure catch crops increased subsequent cereal yields close to 30%. The FSGM increased subsequent cereal yields significantly in two years, but across the rotation the yields were comparable to those of the treatments without green-manure catch crop. To achieve acceptable yields under Norwegian conditions, more than 25% of the land should be used for full-season green manure, or this method combined with green-manure catch crops. The accumulated amount of N in aboveground biomass in late autumn did not compensate for the N removed by cereal yields. To account for the deficiency, the roots of the green-manure catch crops would have to contain about 60% of the total N (tot-N) required to balance the cereal yields. Such high average values for root N are likely not realistic to achieve. However, measurement of biomass in late autumn may not reflect all N made available to concurrent or subsequent main crops.  相似文献   

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

Trond K. Haraldsen  Tore E. Sveistrup 《Soil & Tillage Research》1994,29(4)

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.  相似文献   

Carbon mineralization, fungal and bacterial growth, and enzyme activities as affected by contact between crop residues and soil   总被引：18，自引：0，他引：18  

Trond M. Henriksen  Tor A. Breland 《Biology and Fertility of Soils》2002,35(1):41-48

The degree of contact between crop residues and the soil matrix, as determined by the method of residue incorporation, affects decomposition dynamics both under natural and experimental conditions. In microcosm experiments we tested the hypothesis that poor residue-soil contact reduces the decomposition of structural plant constituents through delayed colonization by microorganisms degrading cellulose and hemicellulose. Barley straw or red clover foliage was either confined in buried mesh bags or homogeneously mixed into a loamy topsoil or a silty subsoil to create poor or intimate residue-soil contact in microbiologically rich and less rich environments, respectively. Soil type had no effect on decomposition of the easily degradable clover residues, but cumulative mineralization of barley straw C after 52 days at 15°C was less in the subsoil than in the topsoil by 12% of initial C. For clover material, poor soil contact increased cumulative C mineralization by 5% of initial C in the loamy topsoil but had no effect in the silty subsoil. For the more slowly degradable, cellulose- and hemicellulose-rich straw, on the other hand, poor soil contact reduced C mineralization by 6% of initial C. The results from the loamy topsoil were confirmed in a second experiment in a sandy topsoil. The reduced decomposition of straw with poor soil contact could not be explained by less favourable abiotic conditions, N deficiency nor exclusion of larger animals by mesh bags. Reduced straw-soil contact delayed measured increases in fungal ergosterol concentration, ratio of fungal to bacterial substrate-induced respiration, number of cellulase-producing, colony-forming bacterial units and activity of cellulases and hemicellulase on the residues. Thus, the results supported our hypothesis and underscore the importance of ensuring representative conditions for the soil microflora when decomposition dynamics are studied in microcosms experiments designed to mimic field conditions.  相似文献