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- Balk, Lennart, et al.
(författare)
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Wild birds of declining European species are dying from a thiamine deficiency syndrome.
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 106:29, s. 12001-12006
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Tidskriftsartikel (refereegranskat)abstract
- Wild birds of several species are dying in large numbers from an idiopathic paralytic disease in the Baltic Sea area. Here, we demonstrate strong relationships between this disease, breeding failure, and thiamine (vitamin B(1)) deficiency in eggs, pulli, and full-grown individuals. Thiamine is essential for vertebrates, and its diphosphorylated form functions as a cofactor for several life sustaining enzymes, whereas the triphosphorylated form is necessary for the functioning of neuronal membranes. Paralyzed individuals were remedied by thiamine treatment. Moreover, thiamine deficiency and detrimental effects on thiamine-dependent enzymes were demonstrated in the yolk, liver, and brain. We propose that the mortality and breeding failure are part of a thiamine deficiency syndrome, which may have contributed significantly to declines in many bird populations during the last decades.
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| 2. |
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| 3. |
- Karlsson, Jenny, et al.
(författare)
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Hazard identification of contaminated sites-ranking potential toxicity of organic sediment extracts in crustacean and fish
- 2008
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Ingår i: Journal of Soils and Sediments. - : Springer Science and Business Media LLC. - 1439-0108 .- 1614-7480. ; 8:4, s. 263-274
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Tidskriftsartikel (refereegranskat)abstract
- Background, aim, and scope It is well known that contaminated sediments represent a potential long-term source of pollutants to the aquatic environment. To protect human and ecosystem health, it is becoming common to remediate contaminated sites. However, the great cost associated with,e.g., dredging in combination with the large numbers of contaminated sites makes it crucial to pinpoint those sites that are in greatest need of remediation. In most European countries, this prioritization process has almost exclusively been based on chemical analyses of known substances; only seldom toxicity data has been considered. The main objective of the current study was therefore to develop a tool for hazard identification of sediment by ranking potential toxicity of organic sediment extracts in a crustacean and a fish. A secondary objective was to investigate the difference in potential toxicity between compoundswith different polarities. Materials and methods Early life stages of the crustacean Nitocra spinipes and the fish Oncorhynchus mykiss, which represent organisms from different trophic levels (primary and secondary consumer) and with different routes of exposure(i.e., ingestion through food, diffusive uptake, and maternal transfer), were exposed to hexane and acetone fractions(semi-polar compounds) of sediment from five locations,ranging from heavily to low contaminated. Preliminary tests showed that the extracts were non-bioavailable to the crustacean when exposed via water, and the extracts were therefore loaded on silica gel. Rainbow trout embryos were exposed using nano-injection technique. Results and discussion Clear concentration–response relationships of both mortality and larval development were observed in all tests with N. spinipes. Also for rainbow trout,the observed effects (e.g., abnormality, hemorrhage, asymmetric yolk sac) followed a dose-related pattern. Interestingly, our results indicate that some of the locations contained toxic semi-polar compounds, which are normally not considered in risk assessment of sediment since they are focused on compounds isolated in the hexane fraction. Conclusions The ranking of the five sediments followed the expected pattern of potential toxicity in both organisms, i.e.,sediments with known pollution history caused major effects while reference sediments caused minor effects in the two test systems. Silica gel turned out to be an excellent carrier for exposure of N. spinipes to very hydrophobic and otherwise non-bioavailable sediment extracts. Recommendations and perspectives Since both test systems demonstrated that a substantial part of the potential toxicity was caused by semi-polar compounds in the acetone fractions,this study enlightens our poor understanding of which compounds are causing adverse effects in environmental samples. Therefore, by investigating potential toxicity (i.e., hazard identification) as a first screening step in prioritizing processes,these implications could be avoided. For proper sediment risk assessment, we however recommend whole sediment toxicity tests to be used for selected sites at following tiers.
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| 5. |
- Sundberg, Henrik, et al.
(författare)
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Contribution of commonly analyzed polycyclic aromatic hydrocarbons (PAHs) in sediment to potential toxicity in early life-stages of rainbow trout (Oncorhynchus mykiss)
- 2006
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Ingår i: Canadian Journal of Fisheries and Aquatic Sciences. - : NRC Research Press. - 0706-652X .- 1205-7533. ; 63:6, s. 1320-1333
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Tidskriftsartikel (refereegranskat)abstract
- In a series of bio-effect-directed fractionation experiments, we investigated the potential toxicity of sediment extracts from a contaminated bay. A previous study investigated abnormalities and hepatic ethoxyresorufin O-deethylase (EROD) activities in rainbow trout (Oncorhynchus mykiss) larvae by exposing newly fertilized eggs to the total extract and to fractions separated by degree of aromaticity. A major part of the potential toxicity was isolated in a fraction containing polycyclic aromatic compounds (PACs). In this study, we prepared a synthetic PAC mixture with 17 commonly analyzed polycyclic aromatic hydrocarbons (PAHs) in amounts equimolar to those found in the sediment PAC fraction. The 17 PAHs, which included 11 of the 16 United States Environmental Protection Agency (US EPA) priority PAHs, were unable to account for the toxicopathic effects observed and could explain less than 4% of the total EROD induction. The lack of a clear relationship between toxicopathic effects and EROD induction underlines the need for a battery of biomarkers for estimating environmental risk. These results reveal the limits of our knowledge regarding compounds responsible for potential toxicity in field situations.
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| 7. |
- Åkerman, Gun, 1948-
(författare)
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Biochemical studies of thiamine deficiency in Baltic salmon (Salmo salar)
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The first part of this thesis is about the development of a method to inject various substances into the yolk of fish eggs. The method was named nanoinjection and enabled the injection of volumes as small as 10-9 L into the yolk of single fish eggs directly after fertilization, with insignificant mortality due to the injection. The nanoinjection method has been shown to be useful in studies of the toxic effects of environmental contaminants in early life stages and is considered to mimic maternal transfer of anthropogenic and natural substances to the egg. The subsequent parts in this thesis concern thiamine (vitamin B1) and the consequences of thiamine deficiency. Since 1995, it is known that the Baltic salmon (Salmo salar) females transfer insufficient amounts of thiamine into their eggs for their offspring to survive, a condition known as the M74 syndrome. The embryonic and larval development of salmon from the river Dalälven (Sweden) was studied during the seasons of 1994–1995 and 1995–1996. Disorders at hatch and symptoms of thiamine deficiency were described. A parallel study compared early development in cod (Gadus morhua) from the Baltic Sea to cod from the Barents Sea. Both salmon and cod from the Baltic Sea showed a number of disorders at hatch. Nanoinjections of thiamine solutions into newly fertilized eggs from Baltic salmon protected the larvae from the M74 syndrome. Larvae with the M74 syndrome had low hepatic activities of the thiamine diphosphate-dependent enzymes transketolase (TK) and the α-ketoglutarate dehydrogenase complex (KGDHC). Also, apparently healthy Baltic salmon yolk-sac larvae showed reduced activities of TK and KGDHC, compared to the offspring from intraperitoneal thiamine-injected females. The result suggested a sublethal thiamine deficiency in the salmon population. The hypothesis that redox-cycling substances affect thiamine metabolism, was tested in rainbow trout (Oncorhynchus mykiss) juveniles. Exposure to paraquat caused a ten-fold increase in the activity of glutathione reductase and elevated the activity of glucose-6-phosphate dehydrogenase, the rate limiting enzyme in the pentose-phosphate shunt. Despite the nine week period of oxidative stress, neither the TK activity nor thiamine concentrations were affected. The underlying cause(s) of the low thiamine concentration in the Baltic salmon is still unknown.
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