In the Gulf of Gdań sk, as in other parts of the Baltic Sea, toxic blooms of Nodularia spumigena are an annual phenomenon. In the present work, the accumulation of nodularin (NOD), a cyanobacterial pentapeptide hepatotoxin, in sediments, blue mussels, and flounders from the Gulf of Gdań sk was studied by enzyme-linked immunosorbent assay (ELISA). In the surface layers of the sediments NOD concentration ranged from 2.3 ng/g dry weight (dw) several months after cyanobacterial bloom to 75 ng/g dw during the bloom. The highest toxin content in mussels was 139 ng/g dw. In two sampling stations situated in the coastal waters of the Gulf of Gdań sk the concentrations of NOD in sediments and mussels were significantly lower than those measured in the Gulf of Finland. In sediments and mussels collected in the Gulf of Gdań sk, the toxin was also detected in March when N. spumigena did not occur. In flounder, NOD accumulated in the liver (489 ng/g dw), guts (21 ng/g dw), and gonads (21 ng/g dw). Hybride quadrupole-time-of-flight liquid chromatography/mass spectrometry/mass spectrometry (TOF-LC/MS/MS) confirmed the presence of NOD in sediment, mussel, and fish samples. Additionally, other NOD analogues, ([DMAdda 3 ]NOD and [dhb 5 ]NOD), were detected in sediments and mussel tissue. No NOD conjugates with reduced glutathione or cysteine were found in fish and mussels. #

Nodularin is a potent hepatotoxic cyclic pentapeptide produced by planktonic cyanobacterium Nodularia spumigena. Bloom and culture samples of the cyanobacterium collected and isolated from the Gulf of Gdańsk, southern Baltic Sea, were analyzed. Hybrid quadrupole-time-of-flight liquid chromatography/mass spectrometry/mass spectrometry (TOF-LC/MS/MS) with ionspray (ISP) and collision-induced dissociation (CID) were used to characterize nodularin and its analogues. The identification process was based on the comparison of recorded product ion spectra with the previously reported FAB-MS/CID (high-energy) mass spectra of the corresponding nodularin variants. Amino acid structures and sequences were derived from the fragmentation pattern of the [M+H](+) ions. Apart from unmodified nodularin with an arginine residue (NOD-R), three demethylated variants have been found. The sites of demethylation were located on aspartic acid [Asp(1)]NOD, the Adda residue [DMAdda(3)]NOD, and dehydrobutyric acid [dhb(5)]NOD. In two other nodularin variants an additional methyl group is located in the Adda [MeAdda]NOD and Glu [Glu(4)(OMe)]NOD residues. The linear NOD and the geometrical isomer of NOD-R, reported earlier in N. spumigena from New Zealand, have also been detected. Two of the total eight nodularin variants characterized in the present study, [dhb(5)]NOD and [MeAdda]NOD, have not been described earlier.

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The composition of eggplant (Solanum melongena L.) leaf cuticular waxes was investigated. Chemical composition was determined as the first step in recognizing the importance to insect pest resistance of eggplant leaf surface chemistry. Waxes were extracted by dipping leaves into dichloromethane for 40 s. Relatively large samples were then fractionated by 'flash chromatography' on silica gel. Compounds were identified on the basis of their mass spectra from GC-MS analysis and retention data from GC-FID analysis, and quantified on the basis of peak areas from GC-FID analysis. Straight-chain alkanes and methyl-branched alkanes were the most abundant wax components. Minor quantities of esters of fatty acids with triterpene and aliphatic alcohols, free triterpene and aliphatic alcohols, sterols, and free fatty acids were also present on the eggplant leaf surface. This method is suitable for analysis of complex mixtures of plant cuticular lipids. It is also applicable to separation of samples for biological tests on insects.

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