Elevation of cytochrome P450-immunopositive protein and DNA damage in mussels (Mytilus edulis) transplanted to a contaminated site

Mytilus edulis were collected from a reference site (Port Quin) and an urban/industrial contaminated site (New Brighton) in the UK during June 1999. Levels of PCBs (sigma7 congeners) and CB-138 were determined to be, respectively, 21 fold and 16 fold higher in the mussel digestive glands from New Brighton. Levels of CYPIA-immunopositive protein were 1.5 fold higher (P < 0.05) at the polluted site but the levels of DNA strand breaks were 1.3 fold higher (P<0.05) at the reference site. Mussels from Port Quin were placed in cages at both sites and both transplanted and indigenous populations sampled in September (13 weeks). Mussels transplanted from the reference site to the industrial site, reported elevated levels of CYP1A-immunopositive protein (1.4 fold; P < 0.05) and higher levels of DNA damage (1.2 fold; P < 0.05) compared to caged populations at the reference site and a PCB loading similar to the populations from the polluted site. Moreover, transplanted mussels had DNA damage 1.8 fold greater (P < 0.05) than indigenous mussels at the transplant site. These changes were small but significant when compared to the observed temporal changes in the indigenous populations.     

CYP1A- and CYP3A-immunopositive protein levels in digestive gland of the mussel Mytilus galloprovincialis from the Mediterranean Sea

CYP1A-immunopositive protein can be elevated in response to planar PAHs and PCBs in Mytilus sp. digestive gland whilst CYP3A-immunopositive protein has been associated with testosterone 6beta-hydroxylation in fish. Levels of CYP1A- and CYP3A-immunopositive protein were determined in Mytilus galloprovincialis digestive gland microsomes collected from 12 sites in the Mediterranean Sea during May and September 2001. CYP1A-immunopositive protein was significantly highest at contaminated sites whilst CYP3A-immunopositive protein was significantly lowest. A weak negative correlation (r2 = 0.21) was seen between CYP1A- and CYP3A-immunopositive protein. Little evidence of differences at the different sampling times was observed. These results confirm previous work indicating elevation of CYP1A-immunopositive protein in Mytilus sp. digestive gland at contaminated sites. Further study is required to characterise CYP3A-like expression in Mytilus and to elucidate the consequences of possible CYP3A-like down-regulation at contaminated sites.     

Bioaccumulation and depuration of Zn and Cd in mangrove oysters (Crassostrea rhizophorae, Guilding, 1828) transplanted to and from a contaminated tropical coastal lagoon

In order to study Zn and Cd accumulation and depuration, a set of oysters, Crassostrea rhizophorae, were transplanted to a metal contaminated coastal lagoon and another one was harvested there and transplanted to a non-polluted site. C. rhizophorae oysters and Perna perna mussels native from both sites were collected in order to monitor variability of metal concentration in resident populations. After three months exposure, oysters transplanted to the polluted site accumulated fourfold Zn (307-1319 microgg(-1)) without reaching the concentration level of resident oysters (9770 microgg(-1)). Cadmium concentrations had a slight but significant decrease during the same period (1.25-0.54 microgg(-1)). Oysters transplanted to the non-polluted site, showed threefold Zn depuration (6727-2404 microgg(-1)), while Cd had no significant variation (0.90-1.45 microgg(-1)). Results showed that transplanted oysters do not reach heavy metal concentrations in indigenous populations suggesting transplanted organisms would be better used to evaluate bioavailability instead of environmental concentrations.     

Imposex and organotin concentrations in Buccinum undatum and Neptunea antiqua from the North Sea: relationship to shipping density and hydrographical conditions

The presence and the development of imposex were investigated in the common whelk (Buccinum undatum) and the red whelk (Neptunea antiqua) from the open North Sea and the Skagerrak. Imposex development was related to levels of organotins in snails and in the fine fractions (< 63 microm) of the sediments they inhabit. The sampling locations were classified according to three levels of traffic densities of ships of > or = 100 gt per day passing within 15 Nautical miles of the sampling station, shipping levels being: high (> 10 ships day(-1)), intermediate (5--10 ships day(-1)), and low (< 5 ships day(-1)). Sampling stations were also classified according to presence or absence of a vertically stratified water column. In the snails the body levels of the butyltin metabolites MBT and DBT and the parent phenyltin compound TPT, were higher than those of TBT and PT metabolites. In the sediment, the parent compounds and the mono-substituted metabolites MBT and MPT were present in the highest concentrations. The highest body levels of all organotin compounds and the highest imposex indices for the common whelk were found at those locations in the Southern Bight and the German Bight that had a high shipping density as well as a homogeneously mixed water column during the whole year. At these locations sediment levels of organotins were also higher than at other sites. In contrast, the body levels of organotins were low and imposex was sometimes even completely absent in snails from stratified deep-water stations in the Skagerrak, despite a very high shipping density in the entrance area of the Baltic. In sediments from stratified locations with low or intermediate shipping densities, organotin compounds were below or close to their respective limits of detection. These stations were located in areas with a stratified water column during the whole year. The results can be explained by postulating a much higher resistance for dissolved organotins to migrate through a pycnocline. Organotins could only transgress through a pycnocline when adsorbed to settling particles that manage to transgress the boundary between layers. N. antiqua could only be obtained in sufficient numbers from deeper water stations, which almost all had a stratified water column. At stations where both snail species were obtained and imposex was present, the imposex index was higher in the red whelk. Hence N. antiqua seems to be the more sensitive species of the two. In the red whelk, imposex development increased with shipping density too, though in the smaller samples the trend was not significant. Average biota-sediment accumulation factors (BSAFs; normalised for lipid content in snails and TOC content in the fraction < 63 microm in sediments) for Buccinum ranged from 0.4 to 1.0 for butyltins and were similar to literature values reported for TBT in other marine species. Higher average BSAF values were found for phenyltins 1.5 (MPT) to 17 (TPT). The high values for TPT match the ranges expected from equilibrium partitioning concepts of persistent hydrophobic compounds. The ratio of live snails to the total number of live snails plus empty shells ranged between 2.5 and 93%. This parameter might be a useful indicator to compare past and present densities of populations of both species in different areas of the North Sea.     

海链藻属的一个新种-囊状海链藻（Thalassiosira scrotiformis sp．nov．）

自六十年代起，由于电子显微镜的广泛应用，使硅藻的形态学及分类学的研究日益深入。近年来由于采用硅藻壳壁上二种超微结构——唇形突(Labiate process)和支持突(strutted process)的形态、数量及其在壳面上的分布在不同的科、属、种的表现不同作为分类标准，使得从十九世纪末以来所采用的形态学的分类依据有了重大的突破。     

Minor constituents in the Martian atmosphere from the ISM/Phobos experiment

Global Martian atmospheric results derived from the infrared imaging spectrometer ISM flown aboard the Phobos 2 Soviet spacecraft are presented. Over low altitude regions the expected CO mixing ratio of (8 +/- 3) x 10(-4) is measured. Variations of the 2.35-micrometers feature are inconsistent with this value over the Great Martian Volcanoes. If the 2.35-micrometers band is entirely attributable to carbon monoxide, the CO mixing ratio is typically depleted by a factor of 3 over these high altitude areas. Orography should play a major role in the existence of this CO "hole." If, however, these spectral variations at 2.35 micrometers are due to the surface composition, the fraction of the surface covered by the responsible mineral must smoothly decrease as the surface elevation decreases. This phenomenon implies a strong interaction between the surface and the atmosphere for the Great Martian Volcanoes. Diurnal behavior and latitudinal variations of water vapor are globally consistent with Viking measurements. During the Phobos observations, the water vapor amounts over the bright equatorial regions range around 11 pr-micrometers during the day. These amounts are slightly larger than those inferred from 1976 to 1979. The lack of global dust storms during 1988-1989 could explain the enhancement of H2O in the atmosphere.     

Proton production in relativistic heavy ion collisions; comparison with a thermodynamical model

Experimental results concerning proton production in nuclear collisions, obtained at Saturne with the Diogene 4 pi facility, are compared with the predictions of a thermodynamical model, using collective velocity distributions combined with a statistical thermodynamics in local rest frames. Experimental differential cross sections for alpha + nucleus and Neon + nucleus central collisions at incident energies between 200 and 800 MeV per nucleon are well reproduced by the model, for an angular range 30-110 degrees in the laboratory system. Extracted values of the temperatures are compared with those given by other authors.