We investigated the growth and chlorophyll-related parameters of the marine diatom Skeletonema marinoi-dohrnii complex （NIES-324） exposed to tributyltin （TBT） or photosystem （PS） II inhibitor Irgarol as a reference chemical for elucidating the effect of TBT on photosynthetic activity. Fifty percent effective concentrations for growth （EC50） were 2.14 μg/L in TBT and 1.14 μg/L in Irgarol. Chlorophyll a content per one cell （pg/cell） was significantly decreased at the highest Irgarol concentration （1.0 μg/L） but chlorophyll c content was not affected. Following TBT treatment, however, both chlorophyll a and c content per cell increased significantly at the highest concentration （2.0 μg/L）. The ratio of chlorophyll a and c content （chl. a/c ratio） decreased significantly and the minimum level of chlorophyll fluorescence （Fo） per μg/mL of chlorophyll a （Fo/chl. a） increased significantly in all Irgarol treatment groups, but TBT had no effect on either parameter. The present results suggest that TBT has no direct effect on electron flow in the photosystem and that the chl. a/c ratio and Fo/chl. a are sensitive bio-markers for detecting the effect of the PSII inhibitor in diatoms.
To compare the distributions of polycyclic aromatic hydrocarbons （PAHs） and alkylated PAHs （alkPAHs） in sessile marine organisms, bivalves were collected from 20 sites along the coastal areas of Osaka Bay in Japan. Both PAHs and alkPAHs in bivalve tissues were determined by GC/MS. Total PAHs （ΣPAHs） were 87.3-361, 212-214 and 70.9-351 ng/g dry weight （dw） in blue mussels, green mussels and oysters, respectively. Meanwhile, total alkPAHs（ ΣalkPAHs） were 466-3293, 950-1788 and 286-2787 ng/g dw in blue mussels, green mussels and oysters, respectively. When compared to their reported concentrations in sediments, ΣPAH were much lower while ΣalkPAH were higher in bivalves. Moreover, ΣalkPAHs in bivalves of each samling site were 1.8-9.8 times higher than ΣPAHs although ΣalkPAHs in sediment of each sampling site were 1.2-4.5 times lower than ΣPAHs. On the other hand, of the PAHs, naphthalene showed the highest concentration in bivalves for most of the sampling sites. Fortunately, benzo（a）pyrene and PAH4 concentrations in bivalves from Osaka Bay were within the EU criteria. For individual alkPAHs in bivalves, the naphthalene, dibenzothiophene, and phenanthrene/anthracene groups were accumulated at relatively high concentrations. These results suggest that the low molecular weight alkPAHs have higher tendency to pollute water columns.
In the present study, gentamicin, which is well known to induce the nephrotoxicities in organisms, were directly injected into the abdominal cavity of carp with nominal concentrations of 0.02 mg/g（ Low group）, 0.063 mg/g（ Middle group） and 0.2 mg/g（High group） and the variations of metabolite profiles in plasma and the relationship between their variations and symptoms on carp were examined, when the nephrotoxicities were caused. In High group, carps seriously affected to exposure and the mortalities of three individuals out of all of five were observed. Meanwhile, although carps in Low and Middle groups were not dead, they were observed decline in urine output, presence with anemia, abdominal selling with ascites, and hematopoietic tissue. In their metabolite profiles, taurine and inositol related to osmoregulation were significantly increased in comparison with control, depending on exposed concentrations of gentamicin from 0.02 to 0.063 mg/g. Ornithine, creatinine, and urine provided the indications of glomeruli condition were also increased in the same range of exposed concentrations. Those increases could be clearly reflected to the symptoms in kidney damages. On the other hand, metabolites for energy generation tended to decrease, because whole bodies of carp were seriously affected to gentamicin exposures and required more energy than usual.
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