Transfer of nodularin to three-spined stickleback (Gasterosteus aculeatus L.), herring (Clupea harengus L.), and salmon (Salmo salar L.) in the northern Baltic Sea.

Nodularin (NODLN) is a hepatotoxin produced by the cyanobacterium Nodularia spumigena, which occurs regularly in the Baltic Sea. The primary aim of this study was to study the transfer of NODLN to three-spined stickleback (Gasterosteus aculeatus L.), herring (Clupea harengus membras L.), and salmon (Salmo salar L.), which were caught from the northern Baltic Sea between August 2002 and August 2003. Liquid chromatography mass spectrometry (LC-MS) was used for NODLN analysis. NODLN was found in both herring (0-90 microgkg(-1)dw) and three-spined sticklebacks samples (2.8-700 microgkg(-1)dw). The recovery for the spiked stickleback samples in vitro was 28%. Only 1 salmon of a total of 10 contained a small amount of NODLN (10 microgkg(-1)dw). However, the high concentrations in individual stickleback suggest that possible transfer to higher trophic levels deserves more research.

Heterogeneity of nodularin bioaccumulation in northern Baltic Sea flounders in 2002.

The cyanobacterial hepatotoxin nodularin is abundantly produced by the cyanobacterium Nodularia spumigena in the Baltic Sea during July-August. Nodularin is a potent hepatotoxin and a tumour promoter, distributed in various Baltic Sea environmental compartments, especially food webs involving mussels. Flounders receive nodularin through consumption of blue mussels. In this study nodularin concentrations in individual flounders (liver) were examined between July and September 2002 (six sample sets, four to 10 samples/set), providing information about contribution of sampling on estimates of bioaccumulation intensity. Toxin was determined using liquid chromatography/mass spectrometry (LC/MS) and enzyme-linked immunosorbent assay (ELISA). Additionally, liver histopathology was examined. Observed toxin concentrations were ND-390 microg kg(-1) dw (LC/MS) and 20-2230 microg kg(-1) dw (ELISA), with maximum concentrations in September (ELISA). The ELISA protocol generally resulted in higher, up to approximately 10-fold, toxin concentrations than LC/MS, with increasing difference toward September. This difference may have originated from different extraction solvents in LC/MS and ELISA, ion suppression in LC/MS, and temporal increase in nodularin metabolites detectable with ELISA. The differences in toxin concentrations between individual liver samples were considerable with relative standard deviation values of 20-154% (LC/MS) and 28-106% (ELISA). Since the precision of the ELISA method employed was <25% and that of LC/MS <10%, it can be concluded that the largest source of error in bioaccumulation estimates may be an inadequate number of samples. Although there were tissue lesions in several liver samples, occurrence of lesions was not related to toxin concentrations.

Structure of the odd-A, shell-stabilized nucleus 253/102No.

In-beam gamma-ray spectroscopic measurements have been made on 253/102No. A single rotational band was identified up to a probable spin of 39/2planck, which is assigned to the 7/2(+)[624] Nilsson configuration. The bandhead energy and the moment of inertia provide discriminating tests of contemporary models of the heaviest nuclei. Novel methods were required to interpret the sparse data set associated with cross sections of around 50 nb. These methods included comparisons of experimental and simulated spectra, as well as testing for evidence of a rotational band in the gammagamma matrix.

Detection of nodularin in flounders and cod from the Baltic Sea.

The brackish water cyanobacterium Nodularia spumigena regularly forms waterblooms in the Baltic Sea. Many N. spumigena strains can produce nodularin, a hepatotoxic penta-peptide, which has caused several animal poisonings in the Baltic Sea area. To improve our understanding of nodularin bioaccumulation in aquatic organisms this study measured nodularin in flounder and cod caught from the Baltic Sea. Flounders were collected from the western Gulf of Finland in July 1996, September 1997, and September 1998, and from the Gulf of Bothnia in August 1997 and September 1998. Flounders were also collected from the coastal areas of Sweden in the Baltic Proper during September 1998. Cod were caught from the southern Baltic Sea in August 1998. Livers and muscles of the 1997 fish were isolated, extracted, and analysed for nodularin using high-performance liquid chromatography (HPLC) and enzyme-linked immunosorbent assay (ELISA) and protein phosphatase 1 (PP1) inhibition assay. Approximately 30-70 ng of nodularin/g dry weight (maximum value 140 ng/g) were found in the liver tissue samples by ELISA and PP1 inhibition. These concentrations were below the detection limit of HPLC. PP1 assay showed inhibition also in muscle samples, but this may due to other compounds present in the muscle extracts rather than NODLN or due to matrix interference. The recovery of nodularin from liver tissue with ELISA and PP1 assays was about 30%. Nodularin concentrations in samples are not corrected for recovery. Although the concentrations of nodularin found in this study are low further studies of nodularin are needed to assess possible bioaccumulation in brackish water food webs.

Time-dependent accumulation of cyanobacterial hepatotoxins in flounders (Platichthys flesus) and mussels (Mytilus edulis) from the northern Baltic Sea.

There is only limited information about the accumulation of algal toxins in aquatic organisms in the Baltic Sea. In this study we measured total cyanobacterial hepatotoxin levels in blue mussel (Mytilus edulis) and flounderi (Platichthys flesus) tissues. Flounder were caught with gillnets from the western Gulf of Finland during July and August 1999. Blue mussels were collected from an enclosure at 3 m depth and from an artificial reef (wreck, 25-35 m depth) in the western Gulf of Finland between June and September 1999. Flounder liver and muscle samples and soft tissues of mussels were analyzed for the cyanobacterial hepatotoxins (nodularin, NODLN and/or microcystins, MCs) using an enzyme-linked immunosorbent assay (ELISA). Results showed a time-dependent accumulation of hepatotoxins in flounder and mussels. In flounder, the maximum concentration 399 +/- 5 (sd) ng NODLN or MC/g dry weight (dw) was found in the liver of specimens caught on 21 August 1999. No hepatotoxins were detected in muscle samples. The maximum concentration of 2150 ng +/- 60 (sd) ng hepatotoxin/g dw was found in the mussel soft tissues collected on 20 August 1999. Temporal NODLN or MC trends indicated depuration of cyanobacterial hepatotoxin from mussels at surface level and an increase in NODLN or MC concentrations in those from the sea bed. These studies showed that despite the low cyanobacteria cell numbers the cyanobacterial hepatotoxins can accumulate in flounder and mussels. This may allow the further transfer of cyanobacterial hepatotoxins in the food web.

Bioaccumulation and detoxication of nodularin in tissues of flounder (Platichthys flesus), mussels (Mytilus edulis, Dreissena polymorpha), and clams (Macoma balthica) from the northern Baltic Sea.

Cyanobacterial hepatotoxin accumulation in mussels (Mytilus edulis, Dreissena polymorpha), clam (Macoma balthica), and flounder (Platichthys flesus) tissues was measured. Flounder were caught with gillnets from the western Gulf of Finland on 21 August 1999, 25 July 2000, and 25 August 2000. Blue mussels were collected from: (1) a steel cage at a depth of 3 m on 20 August 1999, (2) an enclosure at depths of 3-5 m, and (3) an artificial reef (wreck at 25-30 m) in the western Gulf of Finland between June and September 2000. Furthermore, blue mussels were collected from two sites between August and October 2000: south of the town of Hanko at depths of 5 and 20 m in the western Gulf of Finland and south of the city of Helsinki at a depth of 7 m in the central Gulf of Finland. M. balthica and D. polymorpha were collected at a depth of 12 m from Russian waters in the eastern Gulf of Finland on 1-4 August 2000. The samples were analyzed for the cyanobacterial hepatotoxins nodularin (NODLN) and microcystins (MCs) using enzyme-linked immunosorbent assay (ELISA), liquid chromatography-mass spectrometry (LC-MS), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). ELISA indicated a time-dependent accumulation of hepatotoxins in flounder liver up to 400 +/- 10 (SD) microg/kg on 25 August 2000. No hepatotoxins were detected in flounder muscle samples. In blue mussels, collected from an enclosure 3-5 m deep in the western Gulf of Finland on 23 August 2000, ELISA indicated cyanobacterial hepatotoxins up to 1490 +/- 60 microg/kg dry wt. Blue mussels collected from the other sites contained less cyanobacterial hepatotoxins (40-130 microg/kg dry wt). Clams and mussels from Russian waters contained cyanobacterial hepatotoxin at about 100-130 microg/kg dry wt. Total hepatotoxin levels in mussels from enclosures decreased from August to September, indicating at least partial detoxication/depuration of the toxins. LC-MS verified the presence of NODLN in mussels and flounder. Typical detoxication conjugates were observed by MALDI-TOF-MS in mussel samples collected during August 2000. In deeper-living wreck mussels cyanobacterial hepatotoxin levels continued to increase, from August to September, indicating that portions of cyanobacterial hepatotoxins reach the sea floor. NODLN bioaccumulation is a constant phenomenon in the area.

Conversion electron cascades in 254(102)No.

The spectrum of prompt conversion electrons emitted by excited 254No nuclei has been measured, revealing discrete lines arising from transitions within the ground state band. A striking feature is a broad distribution that peaks near 100 keV and comprises high multiplicity electron cascades, probably originating from M1 transitions within rotational bands built on high K states.