Four species of harbour porpoise (Phocoena phocoena) and one herring (Clupea harengus) sample from the southern Baltic Sea were analysed in an attempt to study the concentration and biomagnification of 17 chlordane related compounds (CHLs) including 12 components present in technical chlordane, the toxic metabolites oxychlordane and cis-hepatchlorepoxide and the photoconversion products photoheptachlor and two photo-cis-chlordanes. The concentration and biomagnification ability of CHLs were also compared to other organochlorines such as HCHs (hexachlorocyclohexanes), hexachlorobenzene, DDTs, dieldrin, mirex and PCBs (polychlorinated biphenyls). Of the CHLs analysed, 16 were detected in porpoise and 15 in herring including the photoconversion products. In both species the highest concentrations were found for PCBs and DDTs. The concentration of PCBs and CHLs in porpoise varied from 5700-16,000 and 470-1250 ng/g lipid, and in herring from 1300 and 49 ng/g lipid, respectively. The biomagnification factor (BMF: concentration in organism/concentration in food; all lipid normalized) in porpoise was found to be high for CHLs followed by dieldrin and lowest for HCHs. Among the CHLs, a big variation of BMF (BMF range approximately 1-50) was found e.g., the nonachlorinated compounds biomagnified to the highest degree followed by cis-heptachlorepoxide, photoheptachlor and oxychlordane.

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PubMedDate not supplied

Organochlorine compounds in the Gulf of Bothnia: sediment and benthic species.

Surface sediment, amphipods (Monoporeia affinis), isopods (Saduria entomon) and fourhorn sculpins (Oncocottus quadricornis) were collected at two coastal stations in the Gulf of Bothnia, one in the Bothnian Bay and the other in the Bothnian Sea. The objective was to study the concentrations, composition profiles, bioaccumulation features and spatial differences of organochlorine compounds such as hexachlorocyclohexanes (HCHs), DDTs, hexachlorobenzene (HCBz), chlordanes (CHLs), dieldrin, Mirex and polychlorinated biphenyls (PCBs). All groups of compounds were found in every sample investigated, with the exception of Mirex that was not detected in the sediment samples. The concentrations for e.g. PCBs and CHLs ranged from 700 to 2400 and 70 to 400 ng/g lipid in the specimens. For the corresponding sediments the results were 9.0-9.3 ng/g dw for PCBs and 0.54-0.57 ng/g dw for CHLs, respectively. Bioaccumulation differences between the species with regard to both degree of and type of compound were observed. The highest accumulation potential was found for the cyclodiene compounds including CHLs and Mirex in isopod. Finally, there were only small concentration and bioaccumulation differences between the two stations.

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PubMedDate not supplied

Three-dimensional structure of a specific pre-messenger RNP particle established by electron microscope tomography.

Electron microscope tomography has been used to refine the structural analysis of individual RNP particles synthesized on Balbiani ring genes in Chironomus tentans. The spherical particles have a diameter of 500 A and are composed of a thick RNP ribbon bent into an asymmetrical, four-domain, ring-like configuration. The first domain, containing the 5' end of the transcript, and the fourth domain, containing the 3' end, are close to each other.

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