| 1. |
- Formiga-Cruz, M, et al.
(författare)
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Evaluation of potential indicators of viral contamination in shellfish and their applicability to diverse geographical areas.
- 2003
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Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 69:3, s. 1556-63
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of the concentration of potential indicators of fecal viral pollution in shellfish was analyzed under diverse conditions over 18 months in diverse geographical areas. These microorganisms have been evaluated in relation to contamination by human viral pathogens detected in parallel in the analyzed shellfish samples. Thus, significant shellfish-growing areas from diverse countries in the north and south of Europe (Greece, Spain, Sweden, and the United Kingdom) were defined and studied by analyzing different physicochemical parameters in the water and the levels of Escherichia coli, F-specific RNA bacteriophages, and phages infecting Bacteroides fragilis strain RYC2056 in the shellfish produced, before and after depuration treatments. A total of 475 shellfish samples were studied, and the results were statistically analyzed. According to statistical analysis, the presence of human viruses seems to be related to the presence of all potential indicators in the heavily contaminated areas, where E. coli would probably be suitable as a fecal indicator. The F-RNA phages, which are present in higher numbers in Northern Europe, seem to be significantly related to the presence of viral contamination in shellfish, with a very weak predictive value for hepatitis A virus, human adenovirus, and enterovirus and a stronger one for Norwalk-like virus. However, it is important to note that shellfish produced in A or clean B areas can sporadically contain human viruses even in the absence of E. coli or F-RNA phages. The data presented here will be useful in defining microbiological parameters for improving the sanitary control of shellfish consumed raw or barely cooked.
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| 2. |
- Asplund, Maria. E., 1970, et al.
(författare)
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Ocean acidification and host-pathogen interactions: blue mussels, Mytilus edulis, encountering Vibrio tubiashii
- 2014
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Ingår i: Environmental Microbiology. - : Wiley. - 1462-2912 .- 1462-2920. ; 16:4, s. 1029-1039
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Tidskriftsartikel (refereegranskat)abstract
- Ocean acidification (OA) can shift the ecological balance between interacting organisms. In this study, we have used a model system to illustrate the interaction between a calcifying host organism, the blue mussel Mytilus edulis and a common bivalve bacterial pathogen, Vibrio tubiashii, with organisms being exposed to a level of acidification projected to occur by the end of the 21st century. OA exposures of the mussels were carried out in relative long-term (4 months) and short-term (4 days) experiments. We found no effect of OA on the culturability of V.tubiashii, in broth or in seawater. OA inhibited mussel shell growth and impaired crystalline shell structures but did not appear to affect mussel immune parameters (i.e haemocyte counts and phagocytotic capacity). Despite no evident impact on host immunity or growth and virulence of the pathogen, V.tubiashii was clearly more successful in infecting mussels exposed to long-term OA compared to those maintained under ambient conditions. Moreover, OA exposed V.tubiashii increased their viability when exposed to haemocytes of OA-treated mussel. Our findings suggest that even though host organisms may have the capacity to cope with periods of OA, these conditions may alter the outcome of host–pathogen interactions, favouring the success of the latter.
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| 3. |
- Baden, Susanne Pihl, 1952, et al.
(författare)
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Declining populations of mytilus spp. In north atlantic coastal waters-A swedish perspective
- 2021
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Ingår i: Journal of Shellfish Research. - : National Shellfisheries Association. - 0730-8000. ; 40:2, s. 269-96
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Forskningsöversikt (refereegranskat)abstract
- During the past 2–3 decades, the spatiotemporal distribution of Mytilus spp. in coastal waters of the North Atlantic has changed considerably. In general, reduced abundances of Mytilus are observed, but there is a great degree of local variation, and some areas are also experiencing recovery after declining events. In this review, hypotheses regarding the causes behind the changes are presented with focus on a Swedish perspective. Excessive exploitation of mussel banks combined with direct and indirect effects of climate change are most probably the main drivers of Mytilus spp. decline in large parts of the North Atlantic. On the Swedish west coast, the wild stocks have disappeared despite no overfishing. Paradoxically, they thrive in mussel farms and on other non-demersal substrates. Changes in predation from, for example, increased wintering populations of eiders (Somateria molissima; 10-fold) and green crabs (Carcinus maenas; 3-fold), alteration of natural substrates elicited by eutrophica- tion, and exacerbated by climate change (increased sea surface temperature, precipitation and extreme weather events) are most likely the key factors for the decline. Most anthropogenic stressors may not be decisive by themselves, but combined effects can potentially be fatal to Mytilus spp. adults and larvae.
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| 4. |
- Collin, Betty, 1976, et al.
(författare)
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Characteristics of potentially pathogenic vibrios from subtropical Mozambique compared with isolates from tropical India and boreal Sweden
- 2013
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Ingår i: Fems Microbiology Ecology. - : Oxford University Press (OUP). - 0168-6496 .- 1574-6941. ; 83:2, s. 255-264
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Tidskriftsartikel (refereegranskat)abstract
- Reported outbreaks of Vibrio parahaemolyticus have increased worldwide, particularly in regions of high seafood consumption. In Mozambique, seafood constitutes an important food resource and diarrheal diseases are common among its inhabitants. Edible clams were collected in Maputo Bay during both the dry and rainy seasons, with the results showing the number of viable counts of vibrios in clams to peak during the latter. Vibrio parahaemolyticus was the predominant species identified among the isolated strains. Although only one of 109 total strains carried the tdh virulence gene, 69% of isolates showed evidence of hemolytic capacity when subjected to a functional test. Similar virulence patterns and biochemical properties were found in strains isolated from Indian and Swedish marine waters. Antibiotic resistance was, however, more pronounced in strains isolated from these latter two environments.
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| 5. |
- Collin, Betty, 1976-, et al.
(författare)
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Experimental evaluation of survival of Vibrio parahaemolyticus in fertilized cold‐water sediment
- 2020
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Ingår i: Journal of Applied Microbiology. - 1364-5072 .- 1365-2672. ; 129:1, s. 75-84
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Tidskriftsartikel (refereegranskat)abstract
- Aims: This experimental study focuses on survival and consistence of Vibrio parahaemolyticus in cold‐water sediments and how increasing temperature and nutritional availability can affect growth. Methods and Results: A pathogenic strain of V. parahaemolyticus was inoculated in seawater microcosms containing bottom sediment. Gradually, during 14 days, the temperature was upregulated from 8 to 21°C. Culturable V. parahaemolyticus was only found in the sediment but declined over time and did not recover even after another 2 days at 37°C. Numbers of culturable bacteria matched the amount found by q‐PCR indicating that they did not enter a dormant state, contrary to those in the water layer. After adding decaying phytoplankton as fertilizer to the microcosms of 8 and 21°C for 7 and 14 days, the culturability of the bacteria increased significantly in the sediments at both temperatures and durations of exposure. Conclusion: The study showed that V. parahaemolyticus can stay viable in cold‐water sediment and growth was stimulated by fertilizers rather than by temperature. Significance and Impact of the Study: Vibrio parahaemolyticus is a common cause of seafood‐borne gastroenteritis and is today recognized in connection to increasing ocean temperature. The results indicate that this pathogen should be considered a risk in well‐fertilized environments, such as aquacultures, even during cold periods.
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| 6. |
- Collin, Betty, 1976, et al.
(författare)
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Faecal Contaminants in Edible Bivalves from Maputo Bay, Mozambique
- 2008
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Ingår i: The Open Nutrition Journal. - 1874-2882. ; 2, s. 86-93
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Tidskriftsartikel (refereegranskat)abstract
- In Maputo, Mozambique marine bivalves considerably contribute to the diet of the population. This study aimed to investigate seasonal distribution of Escherichia coli and Salmonella in clams from Maputo Bay, and examine their pathogenesis and antibiotic-resistant patterns. Standard multiple tube method revealed that the concentration of coliforms in all samples exceeded the limit for direct consumption, according to EU standards. Thirty-eight percent of the samples contained >60,000 MPN per 100 gram flesh. The occurrence of E. coli did not differ significantly due to season, while Salmonella was present in 100% of the samples during the rainy period and only in 30% during the dry. Multiplex polymerase chain reaction showed that 45% of E. coli isolates were positive for the virulent indicator gene fimA. The Salmonella isolates were identified as S. enterica serovar Typhimurium. Among other isolated coliformic Enterobacteriaceae, Shigella sp. (specie), which in low doses can cause severe gastrointestinal infections, was identified. Antimicrobial susceptibility, recorded by the disk diffusion method, showed resistance to the most commonly used antibiotics. This high levels of faecal contaminants in the clams points out the need for risk assessment and sanitary improvements.
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| 7. |
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| 8. |
- Eriksson, Susanne P., et al.
(författare)
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Stress biology and immunology in Nephrops norvegicus
- 2013
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Ingår i: The ecology and biology of <em>Nephrops norvegicus</em>. - Amsterdam : Academic Press. - 9780124104662 ; , s. 149-200
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Bokkapitel (refereegranskat)abstract
- The Norway lobster Nephrops norvegicus lives at low-light depths, in muddy substrata of high organic content where water salinities are high and fluctuations in temperature are moderate. In this environment, the lobsters are naturally exposed to a number of potential stressors, many of them as a result of the surficial breakdown of organic material in the sediment. This process (early diagenesis) creates a heterogeneous environment with temporal and spatial fluctuations in a number of compounds such as oxygen, ammonia, metals, and hydrogen sulphide. In addition to this, there are anthropogenically generated stressors, such as human-induced climate change (resulting in elevated temperature and ocean acidification), pollution and fishing. The lobsters are thus exposed to several stressors, which are strongly linked to the habitat in which the animals live. Here, the capacity of Nephrops to deal with these stressors is summarised. Eutrophication-induced hypoxia and subsequent metal remobilisation from the sediment is a well-documented effect found in some wild Nephrops populations. Compared to many other crustacean species, Nephrops is well adapted to tolerate periods of hypoxia, but prolonged or severe hypoxia, beyond their tolerance level, is common in some areas. When the oxygen concentration in the environment decreases, the bioavailability of redox-sensitive metals such as manganese increases. Manganese is an essential metal, which, taken up in excess, has a toxic effect on several internal systems such as chemosensitivity, nerve transmission and immune defence. Since sediment contains high concentrations of metals in comparison to sea water, lobsters may accumulate both essential and non-essential metals. Different metals have different target tissues, though the hepatopancreas, in general, accumulates high concentrations of most metals. The future scenario of increasing anthropogenic influences on Nephrops habitats may have adverse effects on the fitness of the animals.
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| 9. |
- Eriksson, Susanne P., 1964, et al.
(författare)
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Stress Biology and Immunology in Nephrops norvegicus
- 2013
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Ingår i: Advances in Marine Biology. - : Elsevier. - 0065-2881. ; 64, s. 149-200
-
Tidskriftsartikel (refereegranskat)abstract
- The Norway lobster Nephrops norvegicus lives at low-light depths, in muddy substrata of high organic content where water salinities are high and fluctuations in temperature are moderate. In this environment, the lobsters are naturally exposed to a number of potential stressors, many of them as a result of the surficial breakdown of organic material in the sediment. This process (early diagenesis) creates a heterogeneous environment with temporal and spatial fluctuations in a number of compounds such as oxygen, ammonia, metals, and hydrogen sulphide. In addition to this, there are anthropogenically generated stressors, such as human-induced climate change (resulting in elevated temperature and ocean acidification), pollution and fishing. The lobsters are thus exposed to several stressors, which are strongly linked to the habitat in which the animals live. Here, the capacity of Nephrops to deal with these stressors is summarised. Eutrophication-induced hypoxia and subsequent metal remobilisation from the sediment is a well-documented effect found in some wild Nephrops populations. Compared to many other crustacean species, Nephrops is well adapted to tolerate periods of hypoxia, but prolonged or severe hypoxia, beyond their tolerance level, is common in some areas. When the oxygen concentration in the environment decreases, the bioavailability of redox-sensitive metals such as manganese increases. Manganese is an essential metal, which, taken up in excess, has a toxic effect on several internal systems such as chemosensitivity, nerve transmission and immune defence. Since sediment contains high concentrations of metals in comparison to sea water, lobsters may accumulate both essential and non-essential metals. Different metals have different target tissues, though the hepatopancreas, in general, accumulates high concentrations of most metals. The future scenario of increasing anthropogenic influences on Nephrops habitats may have adverse effects on the fitness of the animals.
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| 10. |
- Formiga-Cruz, M., et al.
(författare)
-
Distribution of human virus contamination in shellfish from different growing areas in Greece, Spain, Sweden, and the United Kingdom
- 2002
-
Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 68:12, s. 5990-5998
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Tidskriftsartikel (refereegranskat)abstract
- Viral pollution in shellfish has been analyzed simultaneously across a wide range of geographical regions, with emphasis on the concomitant variations in physicochemical characteristics and social features. The methods for sample treatment and for the detection of human enteric viruses were optimized by the participating laboratories. The second part of this study involves the selection of a protocol for virus detection, which was validated by analyzing the distribution and concentration of human viral pathogens under diverse conditions during an 18-month period in four European countries. Shellfish-growing areas from diverse countries in the north and south of Europe were defined and studied, and the microbiological quality of the shellfish was analyzed. Human adenovirus, Norwalk-like virus, and enterovirus were identified as contaminants of shellfish in all the participating countries. Hepatitis A virus was also isolated in all areas except Sweden. The seasonal distribution of viral contamination was also described. Norwalk-like virus appeared to be the only group of viruses that demonstrated seasonal variation, with lower concentrations occurring during warm months. The depuration treatments currently applied were shown to be adequate for reducing Escherichia coli levels but ineffective for the elimination of viral particles. The human adenoviruses detected by PCR correlate with the presence of other human viruses and could be useful as a molecular index of viral contamination in shellfish.
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| 11. |
- Hernroth, Bodil, 1951-, et al.
(författare)
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Alteration of host-pathogen interactions in the wake of climate change : increasing risk for shellfish associated infections?
- 2018
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Ingår i: Environmental Research. - 0013-9351 .- 1096-0953. ; 161, s. 425-438
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Tidskriftsartikel (refereegranskat)abstract
- The potential for climate-related spread of infectious diseases through marine systems has been highlighted in several reports. With this review we want to draw attention to less recognized mechanisms behind vector-borne transmission pathways to humans. We have focused on how the immune systems of edible marine shellfish, the blue mussels and Norway lobsters, are affected by climate related environmental stressors. Future ocean acidification (OA) and warming due to climate change constitute a gradually increasing persistent stress with negative trade-off for many organisms. In addition, the stress of recurrent hypoxia, inducing high levels of bioavailable manganese (Mn) is likely to increase in line with climate change. We summarized that OA, hypoxia and elevated levels of Mn did have an overall negative effect on immunity, in some cases also with synergistic effects. On the other hand, moderate increase in temperature seems to have a stimulating effect on antimicrobial activity and may in a future warming scenario counteract the negative effects. However, rising sea surface temperature and climate events causing high land run-off promote the abundance of naturally occurring pathogenic Vibrio and will in addition, bring enteric pathogens which are circulating in society into coastal waters. Moreover, the observed impairments of the immune defense enhance the persistence and occurrence of pathogens in shellfish. This may increase the risk for direct transmission of pathogens to consumers. It is thus essential that in the wake of climate change, sanitary control of coastal waters and seafood must recognize and adapt to the expected alteration of host-pathogen interactions.
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| 12. |
- Hernroth, Bodil, 1951, et al.
(författare)
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Bacteriostatic suppression in Norway lobster (Nephrops norvegicus) exposed to manganese or hypoxia under pressure of ocean acidification
- 2015
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 159, s. 217-224
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Tidskriftsartikel (refereegranskat)abstract
- Future ocean acidification (OA) and warming following climate change elicit pervasive stressors to the inhabitants of the sea. Previous experimental exposure to OA for 16 weeks at pH levels predicted for 2100 has shown to result in serious immune suppression of the Norway lobster, Nephrops norvegicus. The lobsters are currently affected by stressors such as periodical hypoxia inducing high levels of bioavailable manganese (Mn). Here, we aimed to investigate possible effects of interactions between OA and these stressors on total hemocyte counts (THCs) and on recovery of inoculated bacteria in the lobsters, measured as a proxy for bacteriostatic response. The effects were judged by following numbers of culturable Vibrio parahaemolyticus in hepatopancreas, 4 and 24 h post inoculation in lobsters kept in replicate tanks with six different treatments: either ambient (pCO2∼ 500 atm/pH ∼ 8.1 U) or CO2-manipulated seawater (OA;pCO2 ∼ 1550 atm/pH ∼ 7.6 U) for 8 weeks. During the last 2 weeks, additional stress of either hypoxia (∼23% oxygen saturation) or Mn (∼9 mg L−1) was added except in control treatments. Our results showed clear effect on bacteriostatic response in Norway lobsters exposed to these stressors. In lobsters kept in ambient seawater without additional stressors, the number of culturable bacteria in hepatopancreaswas reduced by ∼34%. In combined treatment of ambient seawater and hypoxia, the reduction was∼23%, while in the Mn-exposed animals, there was no reduction at all. This was also the case in all OA treatments where mean numbers of culturable V. parahaemolyticus tended to increase. In lobsters from ambient seawater with or without hypoxia, the THC was not significantly different as was also the case in OA without additional stressors. However, in OA treatments combined with either hypoxia or Mn, THC was reduced by ∼35%. While the reduction of culturable V. parahaemolyticus in lobsters was clearly affected by these stressors, we found no notable effects on growth, survival or hemolytic properties of the bacteria itself. Thus, we conclude that this predicted stress scenario is beneficial for the pathogen in its interaction with the host. As OA proceeds, it may force the health of the ecologically and economically important N. norvegicus to a tipping point if exposed to more short-term stressors such as the periodical events of hypoxia and Mn. This could impact lobster condition and biomass and may as well increase the risk for bacterial transmission to consumers.
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| 13. |
- Hernroth, Bodil, 1951-
(författare)
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Differentiation and evaluation of the uncertainty of nutrient measurements that relate to field and laboratory activities
- 1999
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Ingår i: Marine Pollution Bulletin. - 0025-326X .- 1879-3363. ; 38:5, s. 407-409
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Tidskriftsartikel (refereegranskat)abstract
- When accrediting an environmental monitoring programme, including sampling, storage and analyses of seawater, it is desirable to provide an estimate of the uncertainty of individual components that affect the results, The aim of this study was to clarify the significance between different contributors to the total uncertainty. The Mann-Whitney statistical test showed that the uncertainty associated with sampling conditions was significant when analysing ammonia, nitrite and phosphate, Analyses of ammonia, also showed that the fine structure 'patchiness' of the seawater, reinforced the outdoor contribution of uncertainty.
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| 14. |
- Hernroth, Bodil, 1951, et al.
(författare)
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Environmental factors influencing human viral pathogens and their potential indicator organisms in the blue mussel, Mytilus edulis: the first Scandinavian report
- 2002
-
Ingår i: Applied and Environmental Microbiology. - 0099-2240 .- 1098-5336. ; 68:9, s. 4523-4533
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Tidskriftsartikel (refereegranskat)abstract
- This study was carried out in order to investigate human enteric virus contaminants in mussels from three sites on the west coast of Sweden, representing a gradient of anthropogenic influence. Mussels were sampled monthly during the period from February 2000 to July 2001 and analyzed for adeno-, entero-, Norwalk-like, and hepatitis A viruses as well as the potential viral indicator organisms somatic coliphages, F-specific RNA bacteriophages, bacteriophages infecting Bacteroides fragilis, and Escherichia coli. The influence of environmental factors such as water temperature, salinity, and land runoff on the occurrence of these microbes was also included in this study. Enteric viruses were found in 50 to 60% of the mussel samples, and there were no pronounced differences between the samples from the three sites. E. coli counts exceeded the limit for category A for shellfish sanitary safety in 40% of the samples from the sites situated in fjords. However, at the site in the outer archipelago, this limit was exceeded only once, in March 2001, when extremely high levels of atypical indole-negative strains of E. coli were registered at all three sites. The environmental factors influenced the occurrence of viruses and phages differently, and therefore, it was hard to find a coexistence between them. This study shows that, for risk assessment, separate modeling should be done for every specific area, with special emphasis on environmental factors such as temperature and land runoff. The present standard for human fecal contamination, E. coli, seems to be an acceptable indicator of only local sanitary contamination; it is not a reliable indicator of viral contaminants in mussels. To protect consumers and get verification of "clean" mussels, it seems necessary to analyze for viruses as well. The use of a molecular index of the human contamination of Swedish shellfish underscores the need for reference laboratories with high-technology facilities.
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| 15. |
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| 16. |
- Hernroth, Bodil, 1951-
(författare)
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Factors influencing bactericidal activity of blue mussel (Mytilus edulis) haemocytes against Salmonella typhimurium
- 2003
-
Ingår i: Fish and Shellfish Immunology. - 1050-4648 .- 1095-9947. ; 14:2, s. 93-104
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Tidskriftsartikel (refereegranskat)abstract
- This study showed that in vitro survival of Salmonella typhimurium, after exposure to haemocytes of Mytilus edulis, was significantly affected by the lipopolysaccharides (LPS) structures expressed on the cell surface of the bacteria. Survival seemed to be affected by the surrounding temperature as well. Mussel haemocytes were in vitro exposed to mutants of S. typhimurium, expressing differences in O -antigen polysaccharide chains and core sugars of LPS on their cell surface. Surviving cells of the mutants were determined after incubation with the haemocytes at different temperatures, using a colorimetric assay. In addition, a complementary study on clearance of these mutants, inoculated into the adductor muscle of mussels, was performed at 6 and 20 degrees C. It was concluded that the survival index (SI%) measured in vitro for the mutant with complete LPS was significantly lower at 6 degrees C (c.15%) compared to that at 14 and 20 degrees C (c.70%). SI% for the other mutants was c.35-45% and was not affected by temperature. The in vivo study at 20 degrees C showed that during the first 24h, the clearance rate for the mutants with complete LPS was significantly higher than for the others. Thereafter all mutants, with exception for the most deficient, started to increase in numbers and caused death to the mussels. At 6 degrees C the mutants were slowly reduced and after 17 days, viable cells of the mutant with complete LPS were still detectable in the haemolymph. The study indicated that the mussel haemocytes responded in relation to the LPS of the mutants. However, more intact LPS also seemed to protect the bacteria from being killed. The higher temperatures favoured the growth of the mutants that managed to resist the haemocyte defence. Cell surface properties and temperature seem to affect the survival of bacteria in mussels, which consequently can affect risk assessments in regard to public health.
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| 17. |
- Hernroth, Bodil, 1951, et al.
(författare)
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Factors influencing survival of enterotoxigenic Escherichia coli, Salmonella enterica (serovar Typhimurium) and Vibrio parahaemolyticus in marine environments
- 2010
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Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 1574-6941 .- 0168-6496. ; 71:2, s. 272-280
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Tidskriftsartikel (refereegranskat)abstract
- Abstract The presence and persistence of enterotoxigenic Escherichia coli (ETEC) is poorly investigated in marine habitats. Here we compared ETEC with the more studied fecal contaminant, Salmonella enterica serotype Typhimurium (S. enterica) and the marine bacteria Vibrio parahaemolyticus. All three species of bacteria were culturable on agar plates during 8 weeks of incubation in seawater. However, the culturability of ETEC was positively affected by low temperature whereas V. parahaemolyticus was negatively affected. High-nutrient conditions favored the growth of ETEC but not the other bacteria. When the bacteria were fed to blue mussels, V. parahaemolyticus inhibited the filtration activity and the ingestion was lower than that of the enterobacteria. On the other hand, the mussels were less efficient in eliminating V. parahaemolyticus and an in vitro study showed that the hemocytes of three different species of bivalves were not able to kill this strain of V. parahaemolyticus. The bactericidal capacity of bivalves was seemingly an efficient elimination pathway for S. enterica and ETEC. This study showed that ETEC in endemic areas should, to the same degree as S. enterica and V. parahaemolyticus, be taken in consideration when assessing the role of marine environments as a source of enteric infection.
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| 18. |
- Hernroth, Bodil, 1951-, et al.
(författare)
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Factors influencing survival of the entericcontaminants Enterotoxigenic Escherichiacoli and Salmonella enterica(serovar Typhimurium) in comparison to the Autochthonous Pathogen Vibrio parahaemolyticus in marine environments
- 2010
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Ingår i: FEMS Microbiology Ecology. ; 71, s. 272-280
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Tidskriftsartikel (refereegranskat)abstract
- The presence and persistence of enterotoxigenic Escherichia coli (ETEC) is poorlyinvestigated in marine habitats. Here we compared ETEC with the more studied fecal contaminant, Salmonella enterica serotype Typhimurium (S. enterica) and the marine bacteria Vibrio parahaemolyticus. All three species of bacteria were culturable on agar plates during 8 weeks of incubation in seawater. However, the culturability of ETEC was positively affected by low temperature whereas V. parahaemolyticus was negatively affected. High-nutrient conditions favored the growth of ETEC but not the other bacteria. When the bacteria were fed to blue mussels, V. parahaemolyticus inhibited the filtration activity and the ingestion was lower than that of the enterobacteria. On the other hand, the mussels were less efficient in eliminating V. parahaemolyticus and an in vitro study showed that the hemocytes of three different species of bivalves were not able to kill this strain of V. parahaemolyticus. The bactericidal capacity of bivalves was seemingly an efficient elimination pathway forS. enterica and ETEC. This study showed that ETEC in endemic areas should, to the same degree as S. enterica and V. parahaemolyticus, be taken in consideration whenassessing the role of marine environments as a source of enteric infection.
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| 19. |
- Hernroth, Bodil, 1951-, et al.
(författare)
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Immune suppression of the echinoderm Asterias rubens (L.) following long-term ocean acidification
- 2011
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Ingår i: Aquatic Toxicology. - 0166-445X .- 1879-1514. ; 103:3-4, s. 222-224
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Tidskriftsartikel (refereegranskat)abstract
- We compared effects of exposure to predict near-future (2100) ocean acidification (OA; pH 7.7) and normal seawater (Control; pH 8.1) on immune and stress responses in the adult sea star Asterias rubens. Analyses were made after one week and after six months of continuous exposure. Following one week exposure to acidified water, the pH of coelomic fluid was significantly reduced. Levels of the chaperon Hsp70 were elevated while key cellular players in immunity, coelomocytes. were reduced by approximately 50%. Following long-term exposure (six months) levels of Hsp70 returned to control values, whereas immunity was further impaired, evidenced by the reduced phagocytic capacity of coelomocytes and inhibited activation of p38 MAP-kinase. Such impacts of reduced seawater pH may have serious consequences for resistance to pathogens in a future acidified ocean.
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| 20. |
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| 21. |
- Hernroth, Bodil, 1951-, et al.
(författare)
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Impact of ocean acidification on antimicrobial activity in gills of the blue mussel (Mytilus edulis)
- 2016
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Ingår i: Fish and Shellfish Immunology. - : Elsevier. - 1050-4648 .- 1095-9947. ; 55, s. 452-459
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Tidskriftsartikel (refereegranskat)abstract
- Here, we aimed to investigate potential effects of ocean acidification on antimicrobial peptide (AMP) activity in the gills of Mytilus edulis, as gills are directly facing seawater and the changing pH (predicted to be reduced from ∼8.1 to ∼7.7 by 2100). The AMP activity of gill and haemocyte extracts was compared at pH 6.0, 7.7 and 8.1, with a radial diffusion assay against Escherichia coli. The activity of the gill extracts was not affected by pH, while it was significantly reduced with increasing pH in the haemocyte extracts. Gill extracts were also tested against different species of Vibrio (V. parahaemolyticus, V. tubiashii, V. splendidus, V. alginolyticus) at pH 7.7 and 8.1. The metabolic activity of the bacteria decreased by ∼65–90%, depending on species of bacteria, but was, as in the radial diffusion assay, not affected by pH. The results indicated that AMPs from gills are efficient in a broad pH-range. However, when mussels were pre-exposed for pH 7.7 for four month the gill extracts presented significantly lower inhibit of bacterial growth. A full in-depth proteome investigation of gill extracts, using LC-Orbitrap MS/MS technique, showed that among previously described AMPs from haemocytes of Mytilus, myticin A was found up-regulated in response to lipopolysaccharide, 3 h post injection. Sporadic occurrence of other immune related peptides/proteins also pointed to a rapid response (0.5–3 h p.i.). Altogether, our results indicate that the gills of blue mussels constitute an important first line defence adapted to act at the pH of seawater. The antimicrobial activity of the gills is however modulated when mussels are under the pressure of ocean acidification, which may give future advantages for invading pathogens.
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| 22. |
- Hernroth, Bodil, 1951, et al.
(författare)
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Impact of ocean acidification on antimicrobial activity in gills of the blue mussel (Mytilus edulis)
- 2016
-
Ingår i: Fish and Shellfish Immunology. - : Elsevier BV. - 1050-4648 .- 1095-9947. ; 55, s. 452-459
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Tidskriftsartikel (refereegranskat)abstract
- Here, we aimed to investigate potential effects of ocean acidification on antimicrobial peptide (AMP) activity in the gills of Mytilus edulis, as gills are directly facing seawater and the changing pH (predicted to be reduced from ∼8.1 to ∼7.7 by 2100). The AMP activity of gill and haemocyte extracts was compared at pH 6.0, 7.7 and 8.1, with a radial diffusion assay against Escherichia coli. The activity of the gill extracts was not affected by pH, while it was significantly reduced with increasing pH in the haemocyte extracts. Gill extracts were also tested against different species of Vibrio (V. parahaemolyticus, V. tubiashii, V. splendidus, V. alginolyticus) at pH 7.7 and 8.1. The metabolic activity of the bacteria decreased by ∼65–90%, depending on species of bacteria, but was, as in the radial diffusion assay, not affected by pH. The results indicated that AMPs from gills are efficient in a broad pH-range. However, when mussels were pre-exposed for pH 7.7 for four month the gill extracts presented significantly lower inhibit of bacterial growth. A full in-depth proteome investigation of gill extracts, using LC-Orbitrap MS/MS technique, showed that among previously described AMPs from haemocytes of Mytilus, myticin A was found up-regulated in response to lipopolysaccharide, 3 h post injection. Sporadic occurrence of other immune related peptides/proteins also pointed to a rapid response (0.5–3 h p.i.). Altogether, our results indicate that the gills of blue mussels constitute an important first line defence adapted to act at the pH of seawater. The antimicrobial activity of the gills is however modulated when mussels are under the pressure of ocean acidification, which may give future advantages for invading pathogens.
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| 23. |
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| 24. |
- Hernroth, Bodil, 1951-, et al.
(författare)
-
Influence on uptake, distribution and elimination of Salmonella typhimurium in the blue mussel, Mytilus edulis, by the cell surface properties of the bacteria
- 2000
-
Ingår i: Journal of Shellfish Research. - 0730-8000 .- 1943-6319. ; 19:1, s. 167-174
-
Tidskriftsartikel (refereegranskat)abstract
- This study was carried out to investigate whether the cell surface charge of Salmonella typhimurium could influence the kinetics of uptake, distribution, and elimination in the blue mussel, Mytilus edulis. The bacteria (1 mu m) were labeled with Tc-99(m) in the presence of stannous fluoride. Two different concentrations of stannous fluoride were used to produce differences in the cell surface charges of the bacteria. A set of mussels in the investigation were also given Sn-113-labeled microspheres (15 mu m) together with bacteria to compare the impact between particle size and cell surface properties on the distribution kinetics. The distribution of radiolabeled particles in the mussel was followed and analyzed with a computer-aided gamma camera that can detect two isotopes simultaneously. Finally. the mussels were dissected and the radioactivity in the fractions was measured with a well-shielded NaI(Tl) detector. The reduced cell surface charge of S. typhimurium enhanced the preingestive selection on the gills or labial palps as well as the postingestive selection in the digestive glands in such a way that it became similar to the microspheres, despite the size differences. The uptake of the bacteria labeled in the presence of less stannous fluoride was significantly lower. However, the subsequent absorption of these bacteria in the digestive gland was greater, because the recovery of radioactivity outside the digestive tract was higher than for the more manipulated bacteria and the microspheres. Likewise, the elimination of the more manipulated bacteria was similar to that of the microspheres and significantly higher than that of the less affected bacteria. It is concluded that the cell surface properties of bacteria, possibly the charge, influence the uptake, distribution, and elimination in M. edulis and that this factor could have the same influence as size on the uptake capacity.
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| 25. |
- Hernroth, Bodil, 1951-, et al.
(författare)
-
Kan klimatförändringen öka smitta av infektionssjukdomar via havsvatten?
- 2018
-
Ingår i: Man and Biosphere Health. - Kristianstad : Högskolan Kristianstad. - 9789187973352 ; , s. 22-33
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- De pågående klimatförändringarna gör haven allt varmare ochsurare. Dessutom förväntas perioder av intensiva regn att öka, v et bidrar till högre koncentrationer av näringsämnen i havsvattnet. Även sjukdomsframkallande bakterier och virus följer med vattnet från land ut i havet. Näringsämnena kommer att göda algblomningarna, vilket resulterar i fler syrefria bottnar. I bottensedimenten finns det naturligt rikligt med metallen mangan. Den frisätts till vattnet vid syrebrist och kan då tas upp av bottenlevande djur. I spåren av detta har vi genom experimentella långtidsstudier sett negativa effekter på immunförsvaret hos både kräfta, mussla och sjöstjärna. Förmågan att eliminera inkräktande bakterier och virus försämrades och djuren blev mer infektionsbenägna. Den tydligaste effekten såg vi då vi tillsatte mangan. Vi undersöker även hur viabilitet och virulens hos sjukdomsalstrande bakterier i havet påverkas och har bl.a. sett att havslevande bakterier av släktet Vibrio inte far illa av de förändrade faktorerna i havet, vilket indikerar att de kan få ett övertag på demarina organismerna, vars immunförsvar försvagats.
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| 26. |
- Hernroth, Bodil, 1951, et al.
(författare)
-
Manganese induced immune suppression of the lobster, Nephrops norvegicus
- 2004
-
Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 70:3, s. 223-231
-
Tidskriftsartikel (refereegranskat)abstract
- Manganese (Mn) is one of the most abundant elements on earth, particularly in the soft bottom sediments of the oceans. As a micronutrient Mn is essential in the metabolic processes of organisms. However, at high concentrations the metal becomes a neurotoxin with well-documented effects. As a consequence of euthrophication, manganese is released from bottom sediments of coastal areas and the Norway lobsters, Nephrops norvegicus, can experience high levels of bioavailable Mn2+. Here, we present the first report showing that Mn also affects several fundamental processes in the mobilisation and activation of immunoactive haemocytes. When N. norvegicus was exposed to a realistic [Mn2+] of 20 mg l(-1) for 10 days 24.1 mug ml(-1) was recorded in the haemolymph. At this concentration the total haemocyte count was reduced by ca. 60%. By using BrdU as a tracer for cell division, it was shown that the proliferation rate in the haematopoietic tissue did not increase, despite the haemocytepenia. A gene coding for a Runt-domain protein, known to be involved in maturation of immune active haemocytes in a variety of organisms, was identified also in haemocytes of N. norvegicus. The expression of this gene was >40% lower in the Mn-exposed lobsters as judged by using a c DNA probe and the in situ hybridisation technique. In response to non-self molecules, like lipopolysaccharide, (LPS), the granular haemocytes of arthropods are known to degranulate and thereby release and activate the prophenoloxidase, system, necessary for their immune defence. A degranulation assay, tested on isolated granular haemocytes, showed about 75% lower activity in the Mn-exposed lobsters than that for the unexposed. Furthermore, using an enzymatic assay, the activation per se of prophenoloxidase by LPS was found blocked in the Mn-exposed lobsters. Taken together, these results show that Mn exposure suppressiA fundamental immune mechanisms of Norway lobsters. This identifies a potential harm that also exists for other organisms and should be considered when increasing the distribution of bioavailable Mn, as has been done through recently introduced applications of the metal.
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| 27. |
- Hernroth, Bodil, 1951, et al.
(författare)
-
Possibility of Mixed Progenitor Cells in Sea Star Arm Regeneration
- 2010
-
Ingår i: Journal of Experimental Zoology Part B-Molecular and Developmental Evolution. - : Wiley. - 1552-5007 .- 1552-5015. ; 314B:6, s. 457-468
-
Tidskriftsartikel (refereegranskat)abstract
- In contrast to most vertebrates, invertebrate deuterostome echinoderms, such as the sea star Asterias rubens, undergo regeneration of lost body parts. The current hypothesis suggests that differentiated cells are the main source for regenerating arm in sea stars, but there is little information regarding the origin and identity of these cells. Here, we show that several organs distant to the regenerating arm responded by proliferation, most significantly in the coelomic epithelium and larger cells of the pyloric caeca. Analyzing markers for proliferating cells and parameters indicating cell ageing, such as levels of DNA damage, pigment, and lipofuscin contents as well as telomere length and telomerase activity, we suggest that cells contributing to the new arm likely originate from progenitors rather than differentiated cells. This is the first study showing that cells of mixed origin may be recruited from more distant sources of stem/progenitor cells in a sea star, and the first described indication of a role for pyloric caeca in arm regeneration. Data on growth rate during arm regeneration further indicate that regeneration is at the expense of whole animal growth. We propose a new working hypothesis for arm regeneration in sea stars involving four phases: wound healing by coelomocytes, migration of distant progenitor cells of mixed origin including from pyloric caeca, proliferation in these organs to compensate for cell loss, and finally, local proliferation in the regenerating arm J. Exp. Zool. (Mol. Dev. Evol.) 3148:457-468, 2010. (C) 2010 Wiley-Liss, Inc.
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| 28. |
- Hernroth, Bodil, 1951, et al.
(författare)
-
Simulated climate change causes immune suppression and protein damage in the crustacean Nephrops norvegicus
- 2012
-
Ingår i: Fish & Shellfish Immunology. - : Elsevier BV. - 1050-4648 .- 1095-9947. ; 33:5, s. 1095-1101
-
Tidskriftsartikel (refereegranskat)abstract
- Rising atmospheric carbon dioxide concentration is causing global warming, which affects oceans by elevating water temperature and reducing pH. Crustaceans have been considered tolerant to ocean acidification because of their retained capacity to calcify during subnormal pH. However, we report here that significant immune suppression of the Norway lobster, Nephrops norvegicus, occurs after a 4-month exposure to ocean acidification (OA) at a level predicted for the year 2100 (hypercapnic seawater with a pH lowered by 0.4 units). Experiments carried out at different temperatures (5, 10, 12, 14, 16, and 18 °C) demonstrated that the temperature within this range alone did not affect lobster immune responses. In the OA-treatment, hemocyte numbers were reduced by almost 50% and the phagocytic capacity of the remaining hemocytes was inhibited by 60%. The reduction in hemocyte numbers was not due to increased apoptosis in hematopoetic tissue. Cellular responses to stress were investigated through evaluating advanced glycation end products (AGE) and lipid oxidation in lobster hepatopancreata, and OA-treatment was shown to significantly increase AGEs', indicating stress-induced protein alterations. Furthermore, the extracellular pH of lobster hemolymph was reduced by approximately 0.2 units in the OA-treatment group, indicating either limited pH compensation or buffering capacity. The negative effects of OA-treatment on the nephropidae immune response and tissue homeostasis were more pronounced at higher temperatures (12–18 °C versus 5 °C), which may potentially affect disease severity and spread. Our results signify that ocean acidification may have adverse effects on the physiology of lobsters, which previously had been overlooked in studies of basic parameters such as lobster growth or calcification.
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| 29. |
- Hernroth, Bodil, 1951-, et al.
(författare)
-
Sjukare skaldjur i framtidens hav
- 2018
-
Ingår i: HavsUtsik. - Stockholm. ; 01
-
Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Klimatförändringarna försämrar immunförsvaret hos kräftor, musslor och sjöstjärnor, och gör att de lättare får infektioner. De smittsamma bakterierna och virusen ser däremot inte ut att fara illa i den förändrade miljön. En dålig kombination för ekosystemet, och för oss konsumenter av marina skaldjur.
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| 30. |
- Hernroth, Bodil, 1951-
(författare)
-
The influence of temperature and dose on antibacterial peptide response against lipopolysaccharide in the blue mussel, Mytilus edulis.
- 2003
-
Ingår i: Fish and Shellfish Immunology. - 1050-4648 .- 1095-9947. ; 14:1, s. 25-37
-
Tidskriftsartikel (refereegranskat)abstract
- Blue mussels (Mytilus edulis) were inoculated with two different doses of lipopolysaccharides (LPS) or phosphate-saline (PS) buffer under different temperature conditions (6 and 20 degrees C). The activity of the antibacterial peptide fraction, purified through reverse phase chromatography from mussel haemolyph, was compared at different time intervals after the inoculation. The activity was determined as the minimal peptide concentration that inhibited growth of the Gram-negative bacteria Escherichia coli D21, by using radial diffusion assay. The antibacterial activity for mussels inoculated with LPS changed over time, both at 6 and 20 degrees C, but those inoculated with PS-buffer did not. The response was enhanced within a time course of 3h. The higher temperature did increase the inhibitory activity and made the mussel respond at an earlier stage, in comparison to that at 6 degrees C. At 20 degrees C, mussels inoculated with 10 microg of LPS responded faster than those inoculated with 0.1 microg of LPS. In addition, cytotoxic effects of LPS on mussel haemocytes were investigated in vitro, using a colorimetric assay. The survival index (SI%) for haemocytes decreased with 76% at 6 degrees C but increased with 100% at 20 degrees C, irrespective of the dose of LPS. This indicated that LPS did not influence the viability of the haemocytes but the high temperature increased their metabolic state. Likely, antibacterial response was provoked by LPS in a dose-dependent manner and favoured by higher metabolic state of the haemocytes, elicited at higher temperature. These results provide important considerations for variability in the internal defence of mussels and consequently, also the retention of viable human pathogens in mussels.
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| 31. |
- Hernroth, Bodil, 1951, et al.
(författare)
-
The persistence of infectious adenovirus (type 35) in mussels (Mytilus edulis) and oysters (Ostrea edulis)
- 2007
-
Ingår i: International Journal of Food Microbiology. - : Elsevier BV. - 0168-1605 .- 1879-3460. ; 113:3, s. 296-302
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to provide information for improving risk assessment of viral contaminants in bivalves. The persistence of viable adenovirus type 35 (Ad35) after controlled contaminations of blue mussels, Mytilus edulis, and oysters, Ostrea edulis, was studied. Bivalves, kept in running seawater at two different temperatures (4 and 18 degrees C) were sampled after 1, 3, 7, 14, 21, 35, 42, 49, 56, and 70 days. Virus particles were separated from the gills and the digestive gland through ultra high-speed centrifugation. Qualitative PCR analyses of DNA in the virus extracts showed that Ad35 was detectable for 6-10 weeks and quantitative real-time PCR verified a gradual but not linear decrease in copy numbers, within this time interval. The virus genome was detectable to the same degree on the gills as in the digestive gland. When viral extractions were inoculated on A549 cells to investigate the cytopathic effect (CPE) it was shown that Ad35 stayed infectious in oysters, kept at 4 degrees, for about six weeks, which was double the time compared to that for mussels. The detection of the viral genome exceeded the persistence of their infectivity, in most cases with 4-6 weeks. The data were highly variable and the sporadic occurrence of high numbers of accumulated viruses and their remaining infectivity is seemingly a significant factor regarding food safety. (c) 2006 Elsevier B.V. All rights reserved.
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| 32. |
- Hernroth, Bodil, 1951
(författare)
-
Uptake and fate of pathogenic microbes in the blue mussel, Mytilus edulis
- 2002
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Bivalves, like the blue mussel Mytilus edulis, are filter-feeders and can therefore accumulate high numbers of microbes from the surrounding water. These shellfish are considered the main risk for bringing pathogens from domestic outlets in the sea, back to the community. Although Sweden has strict regulations for discharging waste-water, enteric human viruses were frequently found in mussels from the west coast. The viruses occurred even when the present indicator organism for faecal contamination, Escherichia coli, was found in low numbers. The European Commission has suggested bacteriophages (somatic coliphages, F-specific RNA phages, phages infecting Bacteroides fragilis) as more reliable indicators. However, environmental factors, such as water temperature and land run-off, influenced the indicators and human viruses differently and therefore they did not coexist. Furthermore, a series of laboratory experiments were performed in order to investigate if the content of viable bacteria in mussels can be affected by the cell surface properties of the bacteria and by the surrounding temperature. (i) The ingestion of Salmonella typhimurium was significantly increased when the negative cell surface charge of the bacteria was reduced through chemical modification. This treatment also altered the handling of the bacteria in the mussel stomach. Thus, the bacteria were recovered in different amounts and in different organs of the mussels. (ii) Survival of mutants of S. typhimurium when exposed to mussel haemocytes (in vitro) or inoculated into mussel haemolymph, was enhanced for mutants expressing more complete lipopolysaccharide (LPS). These mutants also managed to multiply in vivo and kill mussels when the temperature favoured bacterial growth. (iii) LPS extracted from S. typhimurium showed to be a trigger for antibacterial peptide activity when inoculated in the mussel haemolymph. The activity responded in a dose dependent manner and was enhanced by temperature.It can be concluded that the enrichment in the mussel can differ between microbes due to their cell surface properties. The content of viable microbes in the mussel tissue seemed to be more pronounced for the human bacterial pathogens. Such bacteria had a survival advantage particularly at higher temperatures. Therefore it does not seem adequate to use non-pathogenic E. coli as an indicator for human intestinal pathogens. These results as well as the fact that pathogens circulating in the community can be brought to the mussels via domestic drainage, should be taken into consideration when modelling risk assessment. Indicators should be evaluated with respect to the most risky pathogens present, and how the bivalves can handle these in relation to the particular environmental conditions in the area. Thus, we may have to accept that the choice of reliable indicators will differ between geographical areas and probably also on a seasonal basis.
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| 33. |
- Holm, Ingvar, et al.
(författare)
-
Miljö, medicin och undervisning, hur hänger det ihop? : exempel från projektet mangan och prostatacancer
- 2018
-
Ingår i: Man and Biosphere Health. - Kristianstad : Högskolan Kristianstad. - 9789187973352 ; , s. 16-21
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Forskningsmiljön ”Man and Biosphere Health” är engruppering där forskare från helt olika biologiskakunskapsområden träffas och knyter kontakter. Forskning inom området ”Life Science” (Livsvetenskap), som framförallt innefattar biologi, medicin och biokemi, är världens största tvärdisciplinära forskningsområde med studier av biologisktliv samt de förutsättningar som utgör grunden för fortsatt liv. Unikt för samarbetet inom MABH är kombinationen avekologisk och biomedicinsk kompetens, vilket i vårt fall har inneburit att cellbiologisk forskning har knutits ihop med miljöforskning på ett nyskapande sätt.
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| 34. |
- Holm, Kristina, et al.
(författare)
-
Functional properties of proteins from the coelomic fluid of the wounded sea star Asterias rubens (L)
- 2010
-
Ingår i: Journal of Invertebrate Pathology. - 0022-2011 .- 1096-0805. ; 105:2, s. 197-199
-
Tidskriftsartikel (refereegranskat)abstract
- Impact on viability and adhesion of three protein fractions, separated by size, from the coelomic fluid of wounded Asterias rubens', was tested on autologous coelomocytes. In addition antimicrobial property of the protein fractions was tested on the Gram-negative bacterium Vibrio parahaemolyticus. All fractions promoted viability and the larger proteins facilitated adhesion of the coelomocytes. The strongest antimicrobial effect was caused by the fraction with the smallest proteins.
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| 35. |
- Holm, K., et al.
(författare)
-
Functional properties of proteins from the coelomic fluid of the wounded sea star Asterias rubens (L)
- 2010
-
Ingår i: Journal of Invertebrate Pathology. - : Academic Press Inc.. - 0022-2011 .- 1096-0805. ; 105, s. 197-199
-
Tidskriftsartikel (refereegranskat)abstract
- Impact on viability and adhesion of three protein fractions, separated by size, from the coelomic fluid of wounded Asterias rubens′, was tested on autologous coelomocytes. In addition antimicrobial property of the protein fractions was tested on the Gram-negative bacterium Vibrio parahaemolyticus. All fractions promoted viability and the larger proteins facilitated adhesion of the coelomocytes. The strongest antimicrobial effect was caused by the fraction with the smallest proteins.
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| 36. |
- Holm, K., et al.
(författare)
-
Induced cell proliferation in putative haematopoietic tissues of the sea star, Asterias rubens (L.)
- 2008
-
Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 211:16, s. 2551-2558
-
Tidskriftsartikel (refereegranskat)abstract
- The coelomic fluid of the echinoderm Asterias rubens possesses large populations of circulating coelomocytes. This study aimed to expand the knowledge about the haematopoietic sources of these cells. Injection of the immune-stimulating molecules lipopolysaccharide (LPS) and concanavalin A (ConA) resulted in an increase in coelomocytes. To investigate if these molecules induce cell proliferation in putative haematopoietic tissues (HPTs), short-term exposure of the substitute nucleotide 5-bromo-2'-deoxyuridine (BrdU) was conducted. Immunohistochemical analysis, using fluorescein-labelled antibodies to trace BrdU, showed pronounced cell division in the coelomic epithelium and axial organ. In the pyloric caeca, not considered as an HPT, proliferation was not detected. BrdU labelling of monolayers of cells obtained by collagenase treatment of coelomic epithelium, axial organ and Tiedemann body revealed induced cell proliferation in response to both LPS and ConA while proliferation of pyloric caeca and circulating coelomocytes remained sparse. By using confocal microscopy it was observed that both the morphology and functional behaviour of cells released from explants of coelomic epithelium showed high similarity to those of circulating phagocytes. It was concluded that the increased coelomocyte numbers observed in response to LPS and ConA were reflected in an induced cell proliferation in coelomic epithelium, axial organ and Tiedemann body, which reinforces the idea that these organs are HPTs and the sources of coelomocyte renewal.
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| 37. |
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| 38. |
- Lindahl, Odd, et al.
(författare)
-
Improving marine water quality by mussel farming: A profitable solution for Swedish society
- 2005
-
Ingår i: Ambio. - : Allen Press Inc.. - 0044-7447 .- 1654-7209. ; 34:2, s. 131-138
-
Tidskriftsartikel (refereegranskat)abstract
- Eutrophication of coastal waters is a serious environmental problem with high costs for society globally. In eastern Skagerrak, reductions in eutrophication are planned through reduction of nitrogen inputs, but it is unclear how this can be achieved. One possible method is the cultivation of filter-feeding organisms, such as blue mussels, which remove nitrogen while generating seafood, fodder and agricultural fertilizer, thus recycling nutrients from sea to land. The expected effect of mussel farming on nitrogen cycling was modeled for the Gullmar Fjord on the Swedish west coast and it is shown that the net transport of nitrogen (sum of dissolved and particulate) at the fjord mouth was reduced by 20%. Existing commercial mussel farms already perform this service for free, but the benefits to society could be far greater. We suggest that rather than paying mussel farmers for their work that nutrient trading systems are introduced to improve coastal waters. In this context an alternative to nitrogen reduction in the sewage treatment plant in Lysekil community through mussel farming is presented. Accumulation of bio-toxins has been identified as the largest impediment to further expansion of commercial mussel farming in Sweden, but the problem seems to be manageable through new techniques and management strategies. On the basis of existing and potential regulations and payments, possible win-win solutions are suggested.
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| 39. |
- Lindahl, O, et al.
(författare)
-
Primary production, climatic oscillations, and physico-chemical processes : the Gullmar Fjord time-series data set (1985-1996)
- 1998
-
Ingår i: ICES Journal of Marine Science. - 1054-3139 .- 1095-9289. ; 55:4, s. 723-729
-
Tidskriftsartikel (refereegranskat)abstract
- The primary production of phytoplankton was measured using the C-14-technique in situ from 1985 to 1996 at the mouth of the Gullmar Fjord, located on the Swedish west coast. The mean annual primary production for these 12 years was 241 gC m(-2) year(-1), with an inter-annual Variation of 180 to 339 gC m(-2) year(-1). Time series of monthly means of the North Atlantic Oscillation (NAO), wind, temperature, salinity, nutrients, precipitation, run-off, chlorophyll a, and primary production were compared using correlations on both original and detrended series. The direct correlations with primary production without any time-lag were negative with SE, NW, SW winds and with local and Kattegat run-off. With a 6-month time lag, primary production was strongly positively correlated with SE and NW winds as well as with Kattegat run-off and weakly positively correlated with SW winds. The results suggest the presence of an indirect Link between NAG, the supply of nutrients to Kattegat, wind, and the primary production in the Gullmar Fjord. (C) 1998 International Council for the Exploration of the Sea.
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| 40. |
- Nenonen, Nancy P, 1943, et al.
(författare)
-
Detection of hepatitis A virus genotype IB variants in clams from Maputo Bay, Mozambique.
- 2006
-
Ingår i: Journal of medical virology. - : Wiley. - 0146-6615 .- 1096-9071. ; 78:7, s. 896-905
-
Tidskriftsartikel (refereegranskat)abstract
- Clams provide an important source of food and income for the population of Maputo, Mozambique, where conditions of poor water supply and inadequate sanitation favor endemic infection with hepatitis A virus (HAV). To determine the role of bivalves in an endemic area, clams gathered from Maputo Bay were bought from market and examined for HAV. Four batches, total 150 clams, were sampled over the year. RNA extracted from individual digestive glands was assayed by nested RT-PCR and sequencing of HAV 5' noncoding region (5' NCR). Specific HAV signals were detected in one batch, 23 of 34 clams (67%) testing positive. Phylogenetic analyses of VP3/VP1, VP1/P2A, and 5' NCR determined clustering of clam strains as genotype I, subtype B. In addition to identifying HAV IB strains with predicted conserved amino acid sequence, IB variants exhibiting novel amino acid substitutions at the VP1/P2A junction were detected. HAV strains from clams showed 93%-99% homology with wild-type IB strains from South African outbreaks and from a panel of HAV IgM positive Swedish patients. DNA from enteric human adenovirus 40/41 was found in a limited number of clams from two batches, 6/34 (17%) and 4/35 (11%). Detection of HAV subgenotype IB in bivalves provided indirect evidence of the strains circulating in a densely populated coastal region where HAV is presumed to be hyperendemic. The results suggest that clams may be an important source of HAV in Maputo region, and indicate the need for further molecular study of strains circulating in the indigenous population.
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| 41. |
- Nenonen, Nancy P, 1943, et al.
(författare)
-
Tracing of norovirus outbreak strains in mussels collected near sewage effluents.
- 2008
-
Ingår i: Applied and environmental microbiology. - 1098-5336. ; 74:8, s. 2544-9
-
Tidskriftsartikel (refereegranskat)abstract
- Noroviruses from mussels collected near sewage effluents were compared with local patient outbreak strains. Sequence analyses of RNA polymerase-capsid-poly(A)-3' (3.1-kilobase) regions confirmed the 99.9% similarity between genotype I.1 strains from mussels and patient strains from recreational-bathing outbreaks, indicating the potential usefulness of sentinel norovirus mussel studies in tracing human norovirus contamination of coastal waters.
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| 42. |
- Nilsson Sköld, Helen, 1970, et al.
(författare)
-
Motoric impairment following manganese exposure in asteroide chinoderms
- 2015
-
Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 167, s. 31-37
-
Tidskriftsartikel (refereegranskat)abstract
- In the oceans, naturally occurring manganese (Mn) is released from the sediments during events of hypoxia. While neuro- and immuno-toxic effects of bioavailable manganese are well documented for crustaceans, studies of similar effects of manganese on other marine invertebrates are comparatively few. Here, we developed a new functional test “the repeated turning assay” to investigate if manganese exposure at ∼12 mg L−1 affected motoric behaviour of two asteroid echinoderms, the Common sea star, Asterias rubens, and the Black brittle star, Ophiocomina nigra. By measuring of the turning-over capacity, from dorsal to ventral position, after one and two weeks of manganese exposure, we showed that for both species Mn exposure significantly delayed the ability to turn. After a recovery period of two weeks, the capacity of turning-over was not restored to that of unexposed animals neither for A. rubens nor for O. nigra. Further investigation of sea stars showed that Mn accumulated ∼5 fold in the tube feet, organs involved in their turning-over activity, and the high concentration remained after the recovery period. In the tube feet we also recorded an increased activity of acetylcholinesterase (AChE), here used as a proxy for neuromuscular disturbances. The results indicated that Mn induces neuromuscular disturbance in echinoderms which is important news, given that previous studies have concluded that adult echinoderms are relatively tolerant to Mn.
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| 43. |
- Oweson, Carolina, et al.
(författare)
-
A comparative study on the influence of manganese on the bactericidal response of marine invertebrates
- 2009
-
Ingår i: Fish and Shellfish Immunology. - 1050-4648 .- 1095-9947. ; 27:3, s. 500-507
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Tidskriftsartikel (refereegranskat)abstract
- Manganese, Mn, is a naturally abundant metal in marine sediments. During hypoxic conditions the metal converts into a bioavailable state and can reach levels that have been shown immunotoxic to the crustacean Nephrops norvegicus. For this species it has previously been shown that exposure to 15 mg L(-1) of Mn decreased the number of circulating haemocytes while it for the echinoderm Asterias rubens increased the number of coelomocytes. Here, we compared if five days of exposure to the same concentration of Mn affects the bactericidal capacity of these two species and the mollusc Mytilus edulis when inoculated with the bacterium Vibrio parahaemolyticus. Viable counts of the bacteria were investigated at a time-course post-injection in the blood and the digestive glands of Mn-exposed and un-exposed (controls) animals. Accumulation of Mn was also analyzed in these tissues. When exposed to Mn the haemocyte numbers were significantly reduced in M. edulis and it was shown that the bactericidal capacity was impaired in the mussels as well as in N. norvegicus. This was most obvious in the digestive glands. These two species also showed the highest accumulation of the metal. In A. rubens the bactericidal capacity was not affected and the metal concentration was similar to the exposure concentration. After a recovery period of three days the concentration of Mn was significantly reduced in all three species. However, in M. edulis and N. norvegicus it was still double that of A. rubens which could explain the remaining bactericidal suppression observed in N. norvegicus. This study pointed out that exposure to such Mn-levels that are realistic to find in nature could have effects on the whole organism level, in terms of susceptibility to infections. The effect seemed associated to the accumulated concentration of Mn which differed on species level.
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| 44. |
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| 45. |
- Oweson, Carolina A. M., 1976, et al.
(författare)
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Effects of manganese and hypoxia on coelomocyte renewal in the echinoderm, Asterias rubens (L.)
- 2010
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X .- 1879-1514. ; 100:1, s. 84-90
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Tidskriftsartikel (refereegranskat)abstract
- Manganese (Mn) is a naturally abundant metal and particularly so in soft-bottom oceanic sediments where it generally occurs bound in a four-valent colloidal state as MnO2. When hypoxic conditions occur in bottom waters, the metal reduces to the bioavailable ion Mn2+ and can reach concentrations known to have immunotoxic effects in the crustacean Nephrops norvegicus, reducing numbers of circulating haemocytes as a consequence. However, we have previously shown that Mn seems to have a contrasting effect on the echinoderm Asterias rubens in which it triggers the proliferation of haematopoietic cells and increases coelomocyte numbers. Since elevated Mn levels mostly co-occur with hypoxia in nature, here we investigated whether hypoxia has a negative effect on haematopoiesis. Proliferation and differentiation of coelomocytes and cells in the coelomic epithelium of A. rubens were compared after 3 days of exposure to realistic levels of Mn, hypoxia or a combination of these two parameters. We can confirm that Mn elevated numbers of coelomocytes and increased proliferation of epithelial cells, but hypoxia did not affect these levels. However, hypoxia did affect differentiation of these cells as judged by investigating the expression of a Runt domain transcription factor, which was also cloned and sequenced. Through comparative quantification using a real time PCR technique, we found that exposure to hypoxia had a clearly stimulating effect on mRNA expression of Runt gene in both coelomocytes and epithelial cells. These results indicate that during hypoxic conditions the composition of coelomocyte sub-populations changed. (c) 2010 Elsevier B.V. All rights reserved.
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| 46. |
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| 47. |
- Oweson, Carolina A. M., 1976, et al.
(författare)
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Manganese induced apoptosis in haematopoietic cells of Nephrops norvegicus (L.)
- 2006
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Ingår i: Aquatic Toxicology. - : Elsevier BV. - 0166-445X. ; 77:3, s. 322-328
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Tidskriftsartikel (refereegranskat)abstract
- Manganese (Mn) is highly abundant as MnO2 in marine sediments. During hypoxia in bottom waters, the reduced bioavailable fraction of manganese, Mn2+, increases. Thereby, Norway lobster, Nephrops norvegicus, can experience concentrations up to 1000 times normoxic levels. A previous study has shown that exposure to a realistic concentration of 20 mg l(-1) of Mn for 10 days reduced the number of circulating haemocytes in N. norvegicus significantly. Here we aimed to investigate if apoptosis contributes to the Mn-induced haemocytopenia, with the overall hypothesis that Mn induces apoptosis in a time and concentration dependent manner. N. norvegicus were exposed to Mn (0, 5, 10 and 20 mg l(-1)) for 5 and 10 days. After 5 days of exposure the total haemocyte counts were not affected. However, after 10 days there was a gradual decrease in cell numbers, reaching a reduction by 44% when the animals were exposed to 20 mg Mn l(-1). Apoptosis in cells, released from the haematopoietic tissue, was investigated by using TUNEL assay, which detects specific DNA strand breaks. The fraction of apoptotic cells gradually increased from 2.5% in un-exposed lobsters to 15% in those exposed to 20 mg l(-1) but there was no difference related to the exposure time. A gradual increase of apoptosis was further confirmed by electrophoretic DNA-ladder formation, however to a lower extent in lobsters exposed during 5 days. Cell viability, determined by metabolic activity and cell membrane integrity, was not reduced, indicating that apoptosis rather than necrosis caused reduced number of haemocytes. It was concluded that apoptosis seemed to increase already after 5 days of 5 mg l(-1) of Mn-exposure, although exposure for 10 days was required before it was reflected in the haemocyte numbers. Reduced numbers of haemocytes may increase the prevalence for infections in N. norvegicus in their natural habitat. (c) 2006 Elsevier B.V. All rights reserved.
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| 48. |
- Oweson, Carolina A M, et al.
(författare)
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Manganese induced apoptosisin haematopoietic cells of the lobster, Nephrops norvegicus (L)
- 2006
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Ingår i: Aquatic Toxicology. - 0166-445X. ; 77, s. 322-328
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Tidskriftsartikel (refereegranskat)abstract
- Manganese (Mn) is highly abundant as MnO2 in marine sediments. During hypoxia in bottom waters, the reduced bioavailable fraction ofmanganese, Mn2+, increases. Thereby, Norway lobster, Nephrops norvegicus, can experience concentrations up to 1000 times normoxic levels. A previous study has shown that exposure to a realistic concentration of 20 mg l−1 of Mn for 10 days reduced the number of circulating haemocytes in N. norvegicus significantly. Here we aimed to investigate if apoptosis contributes to the Mn-induced haemocytopenia, with the overall hypothesis that Mn induces apoptosis in a time and concentration dependent manner. N. norvegicus were exposed to Mn (0, 5, 10 and 20 mg l−1) for 5 and 10 days. After 5 days of exposure the total haemocyte counts were not affected. However, after 10 days there was a gradual decrease in cell numbers, reaching a reduction by 44% when the animals were exposed to 20 mg Mn l−1. Apoptosis in cells, released from the haematopoietic tissue, was investigated by using TUNEL assay, which detects specific DNA strand breaks. The fraction of apoptotic cells gradually increased from 2.5% in unexposed lobsters to 15% in those exposed to 20 mg l−1 but there was no difference related to the exposure time. A gradual increase of apoptosis was further confirmed by electrophoretic DNA-ladder formation, however to a lower extent in lobsters exposed during 5 days. Cell viability, determined by metabolic activity and cell membrane integrity, was not reduced, indicating that apoptosis rather than necrosis caused reduced number of haemocytes. It was concluded that apoptosis seemed to increase already after 5 days of 5 mg l−1 of Mn-exposure, although exposure for 10 days was required before it was reflected in the haemocyte numbers. Reduced numbers of haemocytes may increase the prevalencefor infections in N. norvegicus in their natural habitat.
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| 49. |
- Perry, D, et al.
(författare)
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Global environmental changes negatively impact temperate seagrass ecosystems
- 2019
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Ingår i: Ecosphere. - : Wiley. - 2150-8925. ; 10:12, s. 1-18
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Tidskriftsartikel (refereegranskat)abstract
- The oceans are increasingly affected by multiple aspects of global change, with substantial impacts on ecosystem functioning and food-web dynamics. While the effects of single factors have been extensively studied, it has become increasingly evident that there is a need to unravel the complexities related to a multiple stressor environment. In a mesocosm experimental study, we exposed a simplified, multi-trophic seagrass ecosystem (composed of seagrass, two shrimp species, and two intermediate predatory fish species) to three global change factors consisting of simulated storm events (Storms), heat shocks (Heat), and ocean acidification (OA), and the combination of all three factors (All). The most striking result indicated that when all factors were combined, there was a negative influence at all trophic levels, while the treatments with individual factors revealed species-specific response patterns. It appeared, however, that single factors may drive the multi-stressor response. All single factors (i.e., Storms, Heat, and OA) had either negative, neutral, or positive effects on fish and shrimp, whereas no effect was recorded for any single stressor on seagrass plants. The findings demonstrate that when several global change factors appear simultaneously, they can have deleterious impacts on seagrass ecosystems, and that the nature of factors and food-web composition may determine the sensitivity level of the system. In a global change scenario, this may have serious and applicable implications for the future of temperate seagrass ecosystems.
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| 50. |
- Rehnstam-Holm, Ann-Sofi, 1959, et al.
(författare)
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Shellfish and public health: A Swedish perspective
- 2005
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Ingår i: Ambio. - : Allen Press Inc.. - 0044-7447 .- 1654-7209. ; 34:2, s. 139-144
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Tidskriftsartikel (refereegranskat)abstract
- Bivalves are ancient animals that feed by filtering large volumes of water. In this way, phytoplankton, bacteria and viruses from the water column are greatly concentrated in the mussels. The hazards associated with the consumption of mussels are thus dependent on the occurrence and composition of toxic algae and human microbial pathogens in the areas where shellfish are grown. Diarrheic shellfish m toxins have occurred regularly in Sweden during the past 27 years. Peaks of toxins in mussels are mostly recorded from October to December, but the pattern can differ significantly due to location and year, making it hard to predict toxin levels in mussels. With an expansion of aquaculture and a subsequent increase in seafood consumption, better risk management is needed to minimize the effects on humans of algal toxins and human pathogens. New control strategies that have to be implemented are: i) proper site selection of culture installations; ii) regular and cost-efficient monitoring of algae, bacteria and viruses; iii) new indicators for fecal contamination, suitable for the specific locations where shellfish grow; iv) rapid dissemination of information to the industry and public, including risk assessment and advice on how to cope with the situation.
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