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321.
I.?Olivotto S.?Yasumasu G.?Gioacchini F.?Maradonna C.?Cionna O.?CarnevaliEmail author 《Marine Biology》2004,145(6):1235-1241
In the present study, a cDNA for the hatching enzyme of a marine tropical fish, Chysiptera parasema, was cloned. This is the first demonstration of hatching enzyme cDNA from a marine tropical fish. The amino acid (aa) sequence deduced from the cDNA consisted of an 18-aa signal sequence, a 53-aa propeptide sequence and a 196-aa mature enzyme portion, having a consensus active site sequence for astacin family proteases. Phylogenetic analysis showed that the C. parasema enzyme was included in the clade of HCEs (high choriolytic enzymes), one of the hatching enzymes of freshwater fishes such as medaka (Oryzias latipes), masu salmon (Oncorhynchus masou) and zebrafish (Danio rerio), but not in the group of LCEs (low choriolytic enzymes), another type of hatching enzymes identified in the medaka. The developmental expression patterns of the C. parasema HCE gene were highly similar to that of the medaka HCE gene. The results suggested that the hatching enzyme system is highly conserved between these marine and freshwater fish species.Communicated by R. Cattaneo-Vietti, Genova 相似文献
322.
A new energetic substance hexanitrohexaazaisowurtzitane (or CL-20) was tested for its toxicities to various ecological receptors. CL-20 (epsilon-polymorph) was amended to soil or deionized water to construct concentration gradients. Results of Microtox (15-min contact) and 96-h algae growth inhibition tests indicate that CL-20 showed no adverse effects on the bioluminescence of marine bacteria Vibrio fischeri and the cell density of freshwater green algae Selenastrum capricornutum respectively, up to its water solubility (ca. 3.6 mg l(-1)). CL-20 and its possible biotransformation products did not inhibit seed germination and early seedling (16-19 d) growth of alfalfa (Medicago sativa) and perennial ryegrass (Lolium perenne) up to 10,000 mg kg(-1) in a Sassafras sandy loam soil (SSL). Indigenous soil microorganisms in SSL and a garden soil were exposed to CL-20 for one or two weeks before dehydrogenase activity (DHA) or potential nitrification activity (PNA) were assayed. Results indicate that up to 10,000 mg kg(-1) soil of CL-20 had no statistically significant effects on microbial communities measured as DHA or on the ammonium oxidizing bacteria determined as PNA in both soils. Data indicates that CL-20 was not acutely toxic to the species or microbial communities tested and that further studies are required to address the potential long-term environmental impact of CL-20 and its possible degradation products. 相似文献
323.
Chlorophenol compounds are environmental pollutants that are both anthropogenic and xenobiotics. Some of these chemicals are carcinogens and are both toxic to a number biochemical processes. Biotransformation of 2,4-dichlorophenol (2,4-DCP) was studied in the presence of glucose on an upflow anaerobic sludge blanket reactor (UASB) using mixed culture. A continuously operated UASB reactor was employed using mixed synthetic wastewater. Results obtained from the 1.8 L volume capacity UASB reactor were subjected to kinetic evaluation constants. Results indicate that the degradation of 2,4-DCP in the presence of glucose was strongly influenced by the concentration of the compound. High degradation levels were observed when the concentration of 2,4-DCP was in the range of 50-150 mg L(-1). Concentrations of 2,4-DCP above 160 mg L(-1) were toxic to microbes even in the presence of glucose. The maximum degradation of 2,4-DCP was found to be 70.4% when initial concentration of 2,4-DCP was 124 mg L(-1) and glucose concentration of 500 mg L(-1) at hydraulic retention time of 13.2 hr. The biodegradation followed first order reaction kinetics with a rate constant (K) of 0.67, Vmax of 0.244 kg m(-3) day(-1), Ks of 0.117 kg m(-3) day(-1) and correlation coefficient of 0.766. 相似文献
324.
Characterisation of the dilute HCl extraction method for the identification of metal contamination in Antarctic marine sediments 总被引:3,自引:0,他引:3
A regional survey of potential contaminants in marine or estuarine sediments is often one of the first steps in a post-disturbance environmental impact assessment. Of the many different chemical extraction or digestion procedures that have been proposed to quantify metal contamination, partial acid extractions are probably the best overall compromise between selectivity, sensitivity, precision, cost and expediency. The extent to which measured metal concentrations relate to the anthropogenic fraction that is bioavailable is contentious, but is one of the desired outcomes of an assessment or prediction of biological impact. As part of a regional survey of metal contamination associated with Australia's past waste management activities in Antarctica, we wanted to identify an acid type and extraction protocol that would allow a reasonable definition of the anthropogenic bioavailable fraction for a large number of samples. From a kinetic study of the 1 M HCl extraction of two Certified Reference Materials (MESS-2 and PACS-2) and two Antarctic marine sediments, we concluded that a 4 h extraction time allows the equilibrium dissolution of relatively labile metal contaminants, but does not favour the extraction of natural geogenic metals. In a regional survey of 88 marine samples from the Casey Station area of East Antarctica, the 4 h extraction procedure correlated best with biological data, and most clearly identified those sediments thought to be contaminated by runoff from abandoned waste disposal sites. Most importantly the 4 h extraction provided better definition of the low to moderately contaminated locations by picking up small differences in anthropogenic metal concentrations. For the purposes of inter-regional comparison, we recommend a 4 h 1 M HCl acid extraction as a standard method for assessing metal contamination in Antarctica. 相似文献
325.
Nutrient chemistry of River Pinios (Thessalia, Greece) 总被引:2,自引:0,他引:2
The impact of human activities with 3-year monitoring on the fluctuation of nutrients along the Pinios River and its tributaries were studied. Their seasonal variations throughout the years 1996-1998 were also presented. High temperatures, from June to August, cause a restriction of the water flow, an enhancement of nutrient concentration with the subsequent increase of eutrophication. High concentrations of nutrients were observed first in winter (wet period), caused by leaching of fertilizers from terrestrial systems after heavy rainfall, later during the warm months due to low water flow of the river, and at last in autumn when plant organisms began to decompose. The intensive algal and macrophyte growth (spring, summer) resulted in severe depletion of nutrients. Organic carbon showed no seasonal trend but its values were high near the estuaries. Nitrate fluxes were high at the initial station (sources) and the Titarisios tributary, whereas nitrites and ammonium were low. In contrary, the Kalentzis tributary with relatively low nitrate values showed increased values of nitrite ammonium or total nitrogen. On the other hand, the Enipeas tributary showed high SO4 values. Phosphates are remarkably present mainly after the city of Larissa, where sewage and industrial discharges occur. None of the nutrients measured in the Pinios River and its tributaries showed a clear seasonal cycle of concentration. Concentrations of nutrients and organic carbon increased as a consequence of anthropogenic inputs, particularly point discharges from sewage treatment plants (i.e. showing distinct, but variable, concentration peaks), as well as diffuse urban and/or agricultural runoff over long areas during storm events. The agricultural management, the urban pollution, mainly from Larissa City, and the climate conditions in the catchment basin (Thessalia Plain) of Pinios River and its tributaries greatly affect the chemical composition of their waters. 相似文献
326.
Papagiannis I Kagalou I Leonardos J Petridis D Kalfakakou V 《Environment international》2004,30(3):357-362
Lake ecosystems are vulnerable to heavy-metal pollution. Fish samples are considered as one of the most indicative factors, in freshwater systems, for the estimation of trace metals pollution potential. Lake Pamvotis (NW Greece) is a typical Mediterranean ecosystem of great importance in regard to biodiversity and to aesthetic value. The fish species found most commonly in the lake are Cyprinus carpio, Silurus aristotelis, Rutilus ylikiensis, and Carassius gibelio. The aim of the present study is to evaluate the level of contamination of two essential heavy metals (copper and zinc) appearing at high concentrations in lake water in the above four fish species. Metal concentrations were measured by atomic absorption spectroscopy in three different tissues (muscle, liver, gonads) in order to assess the fish contamination. A two-factor analysis of variance, based on the procedure of general linear models, was employed in which fish species (four levels) and fish tissue (three levels) were examined for potential influence on Cu and Zn concentrations. Differences between level means per factor were treated using Tukey's multiple comparisons of means. The study showed that C. carpio and R. ylikiensis presented the highest metal content. Tissues analysis revealed that liver and gonads accumulated the highest levels of Cu and Zn. Metal concentration in the edible part of the examined fish (muscle) were in the safety-permissible levels for human consumption. 相似文献
327.
Worldwide occurrence and effects of antifouling paint booster biocides in the aquatic environment: a review 总被引:18,自引:0,他引:18
Organic booster biocides were recently introduced as alternatives to organotin compounds in antifouling products, after restrictions imposed on the use of tributyltin (TBT) in 1987. Replacement products are generally based on copper metal oxides and organic biocides. This ban has led to an increase in alternative coating products containing the above biocides. The most commonly used biocides in antifouling paints are: Irgarol 1051, diuron, Sea-nine 211, dichlofluanid, chlorothalonil, zinc pyrithione, TCMS (2,3,3,6-tetrachloro-4-methylsulfonyl) pyridine, TCMTB [2-(thiocyanomethylthio) benzothiazole], and zineb. Since 1993, several studies have demonstrated the presence of these biocides in European coastal environment as a result of their increased use. More recently, the presence of these biocides was also revealed in waters from Japan, United States, Singapore, Australia and Bermuda. This paper reviews the currently available data on the occurrence of these biocides in the aquatic environment. Some data dealing with the environmental fate, partitioning, behaviour and risk assessment of antifouling paint booster biocides are also reported in order to discuss the detected levels of contamination. 相似文献
328.
Hrabovskyy V Dzendzelyuk O Katerynchuk I Furgala Y 《Journal of environmental radioactivity》2004,72(1-2):25-33
The results of studies of radionuclide contamination of the soils in the western part of the territory of Shatsk National Natural Park (ShNNP), Volyn region, Ukraine, performed during 1994-2001 are presented. Based on the experimental results, the three-dimensional plot of the 137Cs density contamination for the soils at the territory under investigation has been constructed. The monitoring during 1994-2001 of the 137Cs vertical distributions in the different kinds of soils from the Park and the forecasting of the distribution changes of the depth down to 50 cm for the sod loamy sandy gleyed loamy sand soil of the Park up to 2086 have been performed. 相似文献
329.
Travnikova IG Bazjukin AN Bruk GJ Shutov VN Balonov MI Skuterud L Mehli H Strand P 《Journal of environmental radioactivity》2004,77(1):63-75
Two field expeditions in 1996 studied 137Cs intake patterns and its content in the bodies of adult residents from the village Kozhany in the Bryansk region, Russia, located on the shore of a drainless peat lake in an area subjected to significant radioactive contamination after the 1986 Chernobyl accident. The 137Cs contents in lake water and fish were two orders of magnitude greater than in local rivers and flow-through lakes, 10 years after Chernobyl radioactive contamination, and remain stable. The 137Cs content in lake fish and a mixture of forest mushrooms was between approximately 10-20 kBq/kg, which exceeded the temporary Russian permissible levels for these products by a factor of 20-40. Consumption of lake fish gave the main contribution to internal doses (40-50%) for Kozhany village inhabitants Simple countermeasures, such as Prussian blue doses for dairy cows and pre-boiling mushrooms and fish before cooking, halved the 137Cs internal dose to inhabitants, even 10 years after the radioactive fallout. 相似文献
330.
I. Colombini A. Aloia M. Bouslama M. ElGtari M. Fallaci L. Ronconi F. Scapini L. Chelazzi 《Marine Biology》2002,140(5):1001-1012
Spatial distributions of sand beach arthropods were studied at Zouara (Nefza), a beach dune system along the northwestern coast of Tunisia. Two transects with pitfall traps, perpendicular to the shoreline and placed from sea towards land, captured spontaneously crawling arthropods. The pitfalls were used to obtain data on horizontal zonations for 2 days during different seasons (April, October). In April, in order to assess local, long-shore distributions of surface-active beach invertebrates, ten transects with pitfall traps were placed every 100 m, for 2 days. Core samples were also taken in correspondence with each of the ten transects to obtain the distribution of burrowing individuals. Sand samples were taken for successive laboratory analyses (salinity, grain size and organic contents). Local climatic conditions were also recorded. One isopod (Tylos europaeus, subdivided into three different size classes), two amphipods (Talitrus saltator, Talorchestia brito and indistinguishable juveniles) and four coleopteran species (Eurynebria complanata, Scarites laevigatus, Phytosus nigriventris, Phaleria acuminata) were considered. Mean zonations perpendicular to the shoreline showed that crustaceans were found closer to the sea-line limits than coleopterans and that between seasons some species changed their mean zonation more than others. Local, long-shore distributions of active and burrowing individuals showed that most species were unevenly distributed along the shore. These discontinuous distributions differed according to the species and age class and were mainly related to specific microclimatic conditions and to nutrition. 相似文献