| 1. |
- Callier, Myriam D., et al.
(författare)
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Attraction and repulsion of mobile wild organisms to finfish and shellfish aquaculture: A review
- 2018
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Ingår i: Reviews in Aquaculture. - : Wiley. - 1753-5123 .- 1753-5131. ; 10:4, s. 924-949
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Tidskriftsartikel (refereegranskat)abstract
- © 2017 Wiley Publishing Asia Pty Ltd. Knowledge of aquaculture-environment interactions is essential for the development of a sustainable aquaculture industry and efficient marine spatial planning. The effects of fish and shellfish farming on sessile wild populations, particularly infauna, have been studied intensively. Mobile fauna, including crustaceans, fish, birds and marine mammals, also interact with aquaculture operations, but the interactions are more complex and these animals may be attracted to (attraction) or show an aversion to (repulsion) farm operations with various degrees of effects. This review outlines the main mechanisms and effects of attraction and repulsion of wild animals to/from marine finfish cage and bivalve aquaculture, with a focus on effects on fisheries-related species. Effects considered in this review include those related to the provision of physical structure (farm infrastructure acting as fish aggregating devices (FADs) or artificial reefs (ARs), the provision of food (e.g. farmed animals, waste feed and faeces, fouling organisms associated with farm structures) and some farm activities (e.g. boating, cleaning). The reviews show that the distribution of mobile organisms associated with farming structures varies over various spatial (vertical and horizontal) and temporal scales (season, feeding time, day/night period). Attraction/repulsion mechanisms have a variety of direct and indirect effects on wild organisms at the level of individuals and populations and may have implication for the management of fisheries species and the ecosystem in the context of marine spatial planning. This review revealed considerable uncertainties regarding the long-term and ecosystem-wide consequences of these interactions. The use of modelling may help better understand consequences, but long-term studies are necessary to better elucidate effects.
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| 2. |
- Petersson, Linda, et al.
(författare)
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Sprouts of shoot-clipped oak (Quercus alba and Q. robur) germinants show morphological and photosynthetic acclimation to contrasting light environments
- 2020
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Ingår i: New forests. - : Springer. - 0169-4286 .- 1573-5095. ; 51, s. 817-834
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Tidskriftsartikel (refereegranskat)abstract
- Sprouting by woody plants can increase species resilience to disturbance and foster regeneration during periods with little recruitment from seed. Though sprouting often plays a critical role in oak forest regeneration, there is little information available on sprouting capacity and sprout physiology at the seedling stage, particularly for new germinants. This study compared sprouting capacity and sprout photosynthesis of shoot-clipped germinants of two temperate oaks established in contrasting light environments. We studied the North American Quercus alba and the European Q. robur, both are in the section Quercus and appear to share similar biological and ecological requirements. Sprouting capacity for both species was enhanced under high light availability (29% more sprouts per plant), a response not previously noted for oak germinants. Seedling sprouts acclimated to high light with a 34% decrease in leaf area ratio, a 56% increase in leaf mass per area, and a 49% increase in the light-saturated maximum photosynthetic rate. Though both species appeared similarly adapted to shoot loss, a greater sprouting capacity (29% more sprouts per plant) and plant-level net photosynthesis (73% higher) was observed for Q. robur, regardless of light environment. As naturally regenerated oak seedlings in forest understories often experience disturbance or stress resulting in shoot loss or die-back, our results highlight the importance of the light environment during early plant development. Our comparison of temperate oaks from different continents should facilitate exchange of successful stand regeneration practices within the range of temperate oak forests.
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| 3. |
- Petersson, M., et al.
(författare)
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Characterization of phase separation in film forming biopolymer mixtures
- 2005
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 6:2, s. 932-941
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Tidskriftsartikel (refereegranskat)abstract
- Enhanced, tailor-made films can be achieved by combining the good gas barrier of the hydrophilic high amylose maize starch (hylon) with the water resistance of the hydrophobic protein zein. Two polymers are not always miscible in solution, and the phase separation behavior of the mixture is therefore important for the final film structure and its properties. Phase separation of a mixture of these two biopolymers was induced either by cooling, which was observed as growing droplets of the hylon phase which in some cases also formed small aggregates, or by solvent evaporation and studied in real-time in a confocal laser scanning microscope. Solvent evaporation had a much stronger effect on phase separation. During the early stage of phase separation, hylon formed large aggregates and subsequently smaller droplets coalesced with other droplets or large hylon aggregates. The later part of the separation seemed to take place through spinodal decomposition. © 2005 American Chemical Society.
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| 4. |
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| 5. |
- Petersson, M., et al.
(författare)
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Kinetics of release from kafirin films
- 2007
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X .- 1873-7137. ; 21:8, s. 1256-1264
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Tidskriftsartikel (refereegranskat)abstract
- Two separate studies were performed. The first studied release of two different preservatives (lactic acid and calcium propionate) from a biopolymer film to a model food with a water activity of aw=0.95. The second investigated the release of four sugars (fructose, maltose, raffinose and stachyose) with different molecular weights from a biopolymer film to a model food with water activities ranging from 0.85 to 0.95. In both studies, the biopolymer films containing the release components were made from kafirin and placed on the model food, consisting of a gel made of gelatine, sucrose and water with well defined water activity. The amount of preservatives and sugars released from the film to the gel were monitored over time using HPLC at different depths in the model food. The release of preservatives was rapid in both cases, and a gradient of released substances had already formed after 2 h in the model food. The gradients levelled out with time. Calcium propionate had a somewhat faster release than lactic acid. The water activity of the model food had a large impact on the release of sugars. A slow release was observed in the model food with aw=0.85, while a much more rapid release occurred in the model food with aw=0.95. There was a limited diffusion depth in the model food with aw=0.85, probably owing to a limited trial time, while the sugars in the model food with aw=0.95 diffused deeper into the model food until the film was depleted of available sugars. © 2006 Elsevier Ltd. All rights reserved.
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| 6. |
- Petersson, M., et al.
(författare)
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Water vapour permeability and mechanical properties of mixed starch-monoglyceride films and effect of film forming conditions
- 2005
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X .- 1873-7137. ; 19:1, s. 123-132
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Tidskriftsartikel (refereegranskat)abstract
- The effect on water vapour permeability (WVP) and mechanical properties of an addition of various amounts of an acetylated monoglyceride (Acetem) to native potato starch (NPS) films was studied. Phase separation was also evaluated by drying the films at different temperatures, since phase separation between starch and Acetem is affected by temperature. Films were gel-cast from a heated solution of NPS (3%). Five different concentrations (0-10%) of Acetem based on NPS were added to the solution and the films were dried at three different temperatures (23, 35 and 50°C). The film properties were evaluated by measuring thickness, moisture content (MC), WVP and mechanical properties and the results were then evaluated with multivariate analysis. The MC was slightly reduced in the films dried in higher temperatures, despite reconditioned samples, and the film thickness increased with an increasing amount of Acetem. The WVP of a pure NPS film was decreased by 27 and 37% with addition of 10% Acetem or high drying temperature, respectively. The mechanical properties were affected mainly by changes in Acetem concentration. A greater amount of Acetem decreased Young's modulus, stress at break and strain at break. Micrographs showed extensive phase separation in the films, but pure bilayer films were not formed. © 2004 Elsevier Ltd. All rights reserved.
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| 7. |
- Schreiber, Olof, et al.
(författare)
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Lactobacillus reuteri prevents colitis by reducing P-selectin-associated leukocyte- and platelet-endothelial cell interactions
- 2009
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Ingår i: American Journal of Physiology - Gastrointestinal and Liver Physiology. - : American Physiological Society. - 0193-1857 .- 1522-1547. ; 296:3, s. G534-G542
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Tidskriftsartikel (refereegranskat)abstract
- Recent findings indicate that dextran sodium sulfate (DSS)-induced colitis is associated with a prothrombogenic phenotype, with P-selectin playing a major role in platelet recruitment. It has been suggested that probiotics may ameliorate colonic inflammation. We therefore investigated how treatment with Lactobacillus reuteri influenced P-selectin expression, leukocyte and platelet endothelial cell interactions, and colitis severity in DSS-treated rats. Rats were divided into the following four groups: nontreated, DSS treated (5% in drinking water for 9 days), L. reuteri, and L. reuteri and DSS treated. The rats were anesthetized with Inactin (120 mg/kg ip), and the dual radiolabeled monoclonal antibody technique was used to quantify P-selectin expression. Leukocyte-endothelial and platelet-endothelial cell interactions were studied in colonic venules with intravital microscopy. Colitis severity was assessed using a disease activity index. Disease activity index increased, as did the expression of P-selectin in the entire colon after DSS treatment, but both were reduced to control levels with L. reuteri pretreatment. The increased platelet- and leukocyte-endothelial cell interactions after DSS treatment were abolished by pretreatment with L. reuteri. L. reuteri protects against DSS-induced colitis in rats. The protection is associated with reduced P-selectin expression and a decrease in leukocyte- and platelet-endothelial cell interactions.
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