Bacterial resistance against antibiotic treatment has become a major threat to public health. Antimicrobial peptides (AMPs) have emerged as promising alternative agents for treatment of infectious diseases. This study characterizes novel synthetic peptides sequentially derived from the AMP centrocin 1, isolated from the green sea urchin, for their applicability as anti-infective agents.The microbicidal effect of centrocin 1 heavy chain (CEN1 HC-Br), its debrominated analogue (CEN1 HC), the C-terminal truncated variants of both peptides, i.e. CEN1 HC-Br (1--20) and CEN1 HC (1--20), as well as the cysteine to serine substituted equivalent CEN1 HC (Ser) was evaluated using minimal microbicidal concentration assay. The anti-inflammatory properties were assessed by measuring the inhibition of secretion of pro-inflammatory cytokines. All the peptides tested exhibited marked microbicidal and anti-inflammatory properties. No difference in efficacy was seen comparing CEN1 HC-Br and CEN1 HC, while the brominated variant had higher cytotoxicity. C-terminal truncation of both peptides reduced salt-tolerability of the microbicidal effect as well as anti-inflammatory actions. Also, serine substitution of cysteine residue decreased the microbicidal effect. Thus, from the peptide variants tested, CEN1 HC showed the best efficacy and safety profile. Further, CEN1 HC significantly reduced bacterial counts in two different animal models of infected wounds, while Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) failed to develop resistance against this peptide under continued selection pressure. In summary, CEN1 HC appears a promising new antimicrobial agent, and clinical studies are warranted to evaluate the applicability of this AMP for local treatment of infections in man.
This paper investigates possible biological and economic effects of using marine sanctuaries as a management tool, employing cellular automata techniques to model biological growth and area distribution, assuming open access to the fish stock resources outside the protected area. The cellular automata model incorporates a fish harvest model based on standard assumptions. In agreement with previous studies this study confirms that large protected areas are necessary for significant impact on stock conservation, given standard assumptions. The conclusion may however not be equally unambiguous when employing more realistic scenarios, assuming non-uniform distribution of biomass and fishing effort. This study shows that significant stock conserving effects could be obtained even when less that 10% of the total distribution area of the stock is protected from fishing activities.
This paper reviews the bioeconomic literature on habitat-fisheries connections. Many such connections have been explored in the bioeconomic literature; however, missing from the literature is an analysis merging the potential influences of habitat on both fish stocks and fisheries into one general, overarching theoretical model. We attempt to clarify the nature of linkages between the function of habitats and the economic activities they support.More specifically, we identify theoretically the ways that habitat may
enter the standard Gordon-Schaefer model, and nest these interactions in the general model. Habitat influences are defined as either biophysical or bioeconomic. Biophysical effects relate to the functional role of habitat in the growth of the fish stock and may be either essential or facultative to the species. Bioeconomic interactions relate to the effect of habitat on fisheries and can be shown through either the harvest function or the profit function. We review how habitat loss can affect stock, effort, and harvest under open access and maximum economic yield managed fisheries.
This is the trial lecture at the presentation of the author's doctoral thesis at the University of Tromsø. The thesis is available in Munin at http://hdl.handle.net/10037/3111
A thorough review of different aspects on the health implications of using vegetable feed ingredients, both protein and lipid alternatives to fishmeal and fish oil, plus possible additions of immunostimulants, also including a short chapter on undesirable components, the use of genetically modified plants, and how processing may affect feed quality and availability, are given in the different chapters of the present risk assessment. Discussed in particular are Atlantic salmon (Salmo salar), rainbow trout (Onchorhyncus mykiss), Atlantic halibut (Hippoglossus hippoglossus) and Atlantic cod (Gadus morhua). Deemed necessary, since literature on these species is scarce, some theoretical background in the assessment chapter (Chapter 4) includes studies on other species when relevant for the present terms of reference, and to better be able to conclude on possible health implications due to changes in diet ingredients. The answers to the present Terms of Reference are given in Chapter 5 (Risk characterization and conclusions). Chapter 6 presents future challenges that need focus in research to be able to have healthy farming of fish even when volumes increase.
The aim of the present study was to evaluate the intestinal microbial communities of gibel carp (Carassius auratus gibelio) cultivated in two beach ponds at different stocking densities. The two ponds were both ~3.33 hm2 in acreage and ~1.5 m in depth. The stocking densities included one intensive with 2 fish m–3 while the other treated as semi-intensive with 1 fish m–3. The gut microbiota (both allochthonous and autochthonous) were sampled after 135 days of feeding. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rRNA gene segments was used to evaluate the bacterial community. Actinobacteria, Cyanobacteria, Firmicutes, Fusobacteria, Proteobacteria and some unclassified_bacteria taxa were identified in gut samples and feed. Similar bacterial communities (Cs=0.83) were observed with respect to the autochthonous and allochthonous gut microbiota of gibel carp cultured in the intensive culture pond. In contrast to these results, some difference (Cs=0.61) was observed in the gut microbiota of fish reared in the semi-intensive culture pond. Our results indicated that the difference in the bacterial communities between allochthonous bacteria and gut associated bacteria of gibel carp was not constant and was modulated by the stocking density.
Exposure of pristine microbial environments to hydrocarbon contamination stimulates growth of the initially small fraction of indigenous hydrocarbon-degrading bacteria. Custom-made oleophilic fertilizers have been demonstrated to promote oil bioremediation by boosting this proliferation. In the present study, the temporal
dynamics of the bacterial community structure and the individual influences of hydrocarbons and an
oleophilic fertilizer in shaping the community structure was explored during a 78 days bioremediation experiment in a high-Arctic intertidal beach environment. A combination of cultivation independent 16S rRNA gene length-heterogeneity polymerase chain reaction (LH-PCR) profiling and identification of hydrocarbon-degrading isolates based on partial 16S rRNA gene sequences was employed. LH-PCR community profiles in the fertilizer alone and fertilized kerosene plots were largely indistinguishable throughout the experimental period, while kerosene alone plots showed a markedly different composition of
dominant groups. This pointed to the fertilizer as the more decisive factor in shaping the community structure. Most prominent LH-PCR fragments which emerged after kerosene or fertilizer addition could be provisionally assigned to bacterial taxa through coinciding LH-PCR fragment lengths with hydrocarbon degrading isolates obtained from the same type of experimental units. However, a few quantitatively
significant LH-PCR groups had no counterparts among the cultivated bacteria. One of these was affiliated to a hitherto unspeciated subgroup within the Alkanindiges/Acinetobacter clade of Moraxellaceae by a 16S rRNA gene cloning approach.
Regional analyses of possible physical and biological effects of global warming in the Barents Sea area have been carried out recently. Based on such studies possible economic impacts of global warming on the Barents Sea fisheries have been quantified, assuming different types of management
regimes. The EconSimp2000 model, consisting of the ecosystem model AggMult and the fleet model EconMult have been parameterized based on fleet and catch records from the Norwegian
Barents Sea fisheries. The model has been used to study biological and economic impacts of different environmental
scenarios representing possible consequences of global warming. The current environmental situation, including normal seasonal and other variations, has been used as a reference scenario. Several biological and economic indicators have been defined in order to evaluate the simulation results of different environmental scenarios and different types of management regimes. The findings support earlier studies where biological and economic impacts of changes in management regime is found to be more pronounced than impacts caused by effects
of global warming.
A model system for studying lipid oxidation of salted cod muscle was used for investigating the interaction effects of including antioxidants and copper in the brine. The results showed that ascorbate might have pro-oxidative or anti-oxidative effects depending on the ascorbate and metal concentrations. Without added copper in the brine, concentrations of ascorbate ≤500 ppm had a pro-oxidative effect. With 5 ppm copper added in the brine, low concentrations of ascorbate (≤50 ppm) inhibited the formation of TBARS in the cured product. At slightly higher concentrations (100-200 ppm), the anti-oxidative properties were lost. Above 200 ppm the ascorbate reduced the oxidation level in the salt ripened product. The application of ascorbate as an antioxidant in salt curing of cod, requires the use of high concentrations (≥1000 ppm) in the brine. When similar concentrations (0.5 mM) of EDTA, citrate or ascorbate were included with 3 ppm copper in the brine, EDTA was the only antioxidant that efficiently inhibited copper-induced lipid oxidation.
The quality of heavily salted cod was investigated as influenced by adjusted levels of calcium, magnesium and pH in the salt. The investigation was carried out as a multivariate study consisting of two separate 23 full factorial designs. The chemical composition, waterholding capacity, weight and protein yields, colour and firmness were used as quality indicators or responses to the salt mixtures tested. The pH of the salt was positively correlated with the muscle pH of the cured fillet. The pH of the muscle correlated negatively with the relative protein content, the lightness values and the sensory firmness of the cured muscle. The protein yield after the salt curing was also negatively correlated with the muscle pH. Calcium ions increased both the lightness and firmness and magnesium ions increased the lightness of the cured fillet.
Soyabean meal (SBM)-induced enteritis in the distal intestine of the teleost Atlantic salmon (Salmo salar L.) and other salmonids may be considered
a model for diet-related mucosal disorders in other animals and man. The role of the intestinal microbiota in its pathogenesis was explored.
Compared to diets containing fishmeal (FM) as the sole protein source, responses to extracted SBM or the prebiotic inulin, with or without oxytetracycline
(OTC) inclusion, were studied following a 3-week feeding trial. Intestinal microbiota, organosomatic indices and histology, as well as
immunohistochemical detection of proliferating cell nuclear antigen (PCNA), heat shock protein 70 (HSP70) and caspase-3-positive cells in the
distal intestine, were studied. Distal intestine somatic indices (DISI) were higher in inulin and lower in SBM compared to FM-fed fish. The low
DISI caused by SBM corresponded with histological changes, neither of which was affected by OTC, despite a significant decrease in adherent
bacteria count. Image analysis of PCNA-stained sections showed a significant increase in the proliferative compartment length in SBM-fed fish,
accompanied by apparent increases in reactivity to HSP70 and caspase-3 along the mucosal folds, indicating induction of cellular repair and apoptosis,
respectively. Fish fed the SBM diet had higher total number as well as a more diverse population composition of adherent bacteria in the
distal intestine. Thus SBM-induced enteritis is accompanied by induction of distal intestinal epithelial cell protective responses and changes in
microbiota. Putative involvement of bacteria in the inflammatory response merits further investigation.
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There is convincing evidence that consumption of fish and fish oil rich in long-chain (LC) n-3 PUFA (n-3 LCPUFA), EPA (20 : 5n-3) and DHA (22 : 6n-3) reduce the risk of CHD. The aim of the present study was to investigate whether n-3 LCPUFA-enriched food products provide similar beneficial effects as fish oil with regard to incorporation into plasma lipids and effects on cardiovascular risk markers. A parallel 7-week intervention trial was performed where 159 healthy men and women were randomised to consume either 34 g fish pâté (n 44), 500 ml fruit juice (n 38) or three capsules of concentrated fish oil (n 40), all contributing to a daily intake of approximately 1 g EPA and DHA. A fourth group did not receive any supplementation or food product and served as controls (n 37). Plasma fatty acid composition, serum lipids, and markers of inflammation and oxidative stress were measured. Compared with the control group, plasma n-3 LCPUFA and EPA:arachidonic acid ratio increased equally in all intervention groups. However, no significant changes in blood lipids and markers of inflammation and oxidative stress were observed. In conclusion, enriched fish pâté and fruit juice represent suitable delivery systems for n-3 LCPUFA. However, although the dose given is known to reduce the risk of CVD, no significant changes were observed on cardiovascular risk markers in this healthy population.
In the present study the impact on gut microbiology and indigenous gut histology of Atlantic salmon (Salmo salar L.) was investigated following feeding of a control and a prebiotic (EWOS prebiosal®) diet and ex vivo exposure to saline or the probiotic bacterium Carnobacterium divergens. The results showed that ex vivo exposure of C. divergens at 108 CFU ml-1 did not cause cell damage to the intestine tract of Atlantic salmon. Furthermore, prior provision of dietary prebiotic elevated the ability of C. divergens to adhere to the epithelium or mucus layer in the proximal intestine, where culturable heterotrophic bacterial levels (which were identified as C. divergens) were elevated by 234% compared to the control. This effect was not apparent in the distal intestine. The ability of
isolated carnobacteria from the ex vivo experiment to inhibit growth of two fish pathogenic bacteria (Yersinia rückeri and Aeromonas salmonicida ssp. salmonicida) was assessed. Extracellular products from all 11 of the isolated carnobacteria strains, plus the type strain Carnobacterium inhibens CCUG 31728, inhibited the in vitro growth of Y. rückeri. However, only extracellular products from C. divergens isolate 57 inhibited the growth of A. salmonicida.
In this study, the effects of dietary probiotic Bacillus subtilis C-3102 (Calsporin®) on the growth performance, predominant intestinal microbiota, expression of cytokines genes in three organs (liver, intestine and kidney) and
protection against Aeromonas hydrophila infection of koi carp were investigated. Fish were fed two different diets, 1-control diet (non-supplemented) and 2-experimental diet (supplemented with 1 g/kg Calsporin®) for five weeks. Tissue samples were collected at days 0, 10, 20 and 35. The results showed that the weight gain (WG) and feed conversion ratio (FCR) were significantly improved by dietary Bacillus subtilis C-3102 (P < 0.01). Dietary probiotic
did not affect the body skin colouration of koi carp (P > 0.05). Variation of intestinal bacterial communities were studied by denaturing gradient gel electrophoresis (DGGE) which revealed that even though Bacillus subtilis C-3102
was not detected as a prominent component in the intestinal tract of koi carp at any time point, it could affect the intestinal microbiota community at the early stages of the trial, becoming weaker in the later stages. Concerning the gene expression results, the expression of HSP70 gene was up-regulated at day 10 and 35 the liver; no effects were observed in the intestine and kidney. A general trend of upregulation of cytokines expression (IL-1β, IL-10, TNF-α and TGF-β) was observed in liver the (except IL-1β) and intestine, but unchanged in the kidney (except IL-10). The intraperitoneal injection challenge demonstrated that there was no positive effect of dietary B. subtilis C-3102
supplementation against A. hydrophila. These results suggested that B. subtilis C-3102 can provide beneficial effects on growth, feed utilization and modulating intestinal microbiota community.
This paper discusses actual and possible achievements and failures of Codland and examines it from the point of view of efficiency and in terms of distribution. It is argued in favour of the joint analysis of the two approaches when contemplating fisheries management reforms, since such reforms may create both winners and losers. The analysis demonstrates how rent drain from fishing communities and countries may occur despite significant resource rent creation. The change of the Codland economy is illustrated and compared to that of actual countries and to resource economic theory. It is concluded that if distributional and equity objectives matter, other instruments than ITQs, such as conditional tradable fish quotas and vessel licenses, resource taxes, co-management, public ownership, auctions, leases, time limited rights, time and area regulations, territorial user rights (TURFs) and marine protected areas (MPAs), should also be used.