Mercury (Hg) and methyl mercury (MeHg) concentrations in fish from the coastal lagoon of Orbetello, central Italy

Total mercury (Hg tot) and methyl mercury (MeHg) were quantified in several specimens of Dicentrarchus labrax and Sparus aurata from the east basin of the Orbetello lagoon, central Italy. The size of each specimen was recorded to estimate body burdens (BBs); =Hg tot and MeHg were measured in fillets of both species. Hg tot and MeHg in S. aurata ranged between 0.355-1.58 and 0.341-1.53 μg/g wet weight (ww), respectively; in D. labrax, their ranges were 0.284-2.54 and 0.214-2.35 μg/g ww. Approximately 90% of the concentrations measured exceeded Hg tot regulatory maximum level of 0.5 μg/g ww; however, exceedance rate was different in the two species studied. No correlations between specimen size and Hg tot or MeHg BBs were detected in this study.

Adherence of S. bovis to adult buccal epithelial cells

The ability of S. bovis 83/5364, glucan-positive (biotype I) and S. bovis R 81/536 glucan-negative (biotype II) to adhere to buccal epithelial cells (BEC) by lipoteichoic acid (LTA) was examined. LTA from both biotypes was prepared by cold phenol extraction from supernatants of penicillin supplemented cultures and partially purified by Sepharose CL-6B chromatography. Both glucan-positive and glucan-negative S. bovis strains adhered to BEC, but biotype I seemed to be more adhesive. For both biotypes the adhesion was not significantly inhibited by treatment of the bacteria with anti-LTA serum, while the preincubation of BEC with LTA, extracted from S. agalactiae, or cardiolipin strongly decreased the S. bovis binding.