Abstract. Previous studies have described high levels of polychlorobiphenyls (PCB), polybrominated diphenylether (PBDE), toxaphene, p,p 0 -dichlorodiphenyltrichloroethane (DDT), and p,p 0 -dichlorodiphenyldichloroethylene (DDE) in the blubber of the harbour porpoise from the North Sea raising the question of a potential endocrine disruption in this species. In the present study, the thyroids of 57 harbour porpoises from the German and Danish (North and Baltic Seas), Norwegian, and Icelandic coasts have been collected for histological and immunohistological investigations. The number of follicles and the relative distribution of follicles, connective, and solid tissues (%) were quantified in the thyroid of each individual. Then, the potential relationship between the thyroid morphometry data and previously described organic compounds (namely, PCB, PBDE, toxaphene, DDT, and DDE) was investigated using factor analysis and multiple regressions. Thyroid morphology differed strongly between sampling sites. Porpoises from the German (North and Baltic Seas) and Norwegian coasts displayed a high percentage of connective tissues between 30 and 38% revealing severe interfollicular fibrosis and a high number of large follicles (diameter >200 lm). A correlation-based principal component analysis (PCA) revealed two principal components explaining 85.9% of the total variance. The variables PCB, PBDE, DDT, and DDE compounds loaded highest on PC1 whereas toxaphene compound loaded most on PC2. Our results pointed out a relationship between PC1 (PCBs, PBDE, DDE, and DDT compounds) and interfollicular fibrosis in the harbour porpoise thyroids. Such an association is not alone sufficient for a cause-effect relationship but supports the hypothesis of a contaminant-induced thyroid fibrosis in harbour porpoises raising the question of the longterm viability in highly polluted areas.
Bacteriological investigations of seals of the German North and Baltic seas resulted in the isolation of bacteria of the genus Streptococcus belonging to Lancefield's serological groups C, F, and L. According to biochemical, serological, and 16S ribosomal DNA analysis, the group C and group F streptococci were identified as Streptococcus phocae. The group L streptococci could be classified as Streptococcus dysgalactiae subsp. dysgalactiae
Streptococcus phocae, a bacterial pathogen of seals, could reliably be identified by PCR amplification using oligonucleotide primers designed according to species specific segments of the previously sequenced 16S rRNA gene and the 16S-23S rDNA intergenic spacer region of this species. The PCR mediated assay allowed an identification of S. phocae isolated from harbor and gray seals and from Atlantic salmons. No cross-reaction could be observed with 13 different other streptococcal species and subspecies and with Lactococcus garvieae strains investigated for control purposes.
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