摘要:

AbstractLysosomes are cell organelles containing hydrolytic enzymes and involved in intracellular digestion. Numerous environmental contaminants can interfere with lysosomes, and the purpose of the present work was to quantify changes induced by petroleum hydrocarbons on the structure of the lysosomal system of mussel digestive cells. Mussels,Mytilus galloprovincialisLmk., were exposed for three months to the water accommodated fraction (WAF) of two crude oils (URAL and MAYA) and of a lubricant oil. Three different exposure doses (0.6, 6, and 40% WAF) were used for each type of hydrocarbon and mussels were sampled at different time intervals (days 21, 49, and 91). A stereological study, using an automated image analysis system, was made on sections stained for demonstration of β‐glucuronidase activity and four parameters were calculated: lysosomal volume density, surface density, surface to volume ratio, and numerical density. The results indicate that the effect of the exposure dose on lysosomal structure is variable and there is no linear relationship of lysosomal changes with dose. Regarding the effect of the exposure time, two different responses were evidenced: (a) a short‐term response (at day 21) with a decrease in size and numbers of lysosomes and (b) a long‐term response (at days 49 and 91) with an increase in lysosomal size and a decrease in their numbers. The short‐term response may be due to a disintegration process of the digestive cells with subsequent loss of lysosomes and could represent an adaptative response to hydrocarbon exposure. At long exposure times, lysosomal changes, apparently caused by fusion processes giving rise to enlarged lysosomes, correspond to a “general stress response”. ©by John Wi

ISSN:1053-4725    

DOI:10.1002/tox.2530100102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractOver the past 20 years there has been a concerted effort to define and limit the impacts of anthropogenic contaminants in aquatic environments. There are essentially two philosophies that can be employed to regulate and to assess the effects of toxic chemicals in these systems. The first is the water quality objectives research. Under this protocol, laboratory research is used to set an objective, the concentration of a substance or condition that is considered to have no effect on the organisms in an aquatic environment based on a review of the pertinent research. The second approach, environmental health assessment, uses the in situ responses of free‐living organisms in contaminated environments to determine the overall impacts of the environment on those organisms. In this review paper we will attempt to compare and contrast the advantages and disadvantages of the two approaches, and to outline a system whereby they can be used together to enhance our degree of confidence in legislation directed at reducing contaminant impacts. ©by John Wiley&Sons, I

ISSN:1053-4725    

DOI:10.1002/tox.2530100103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractDriedMicrocystis aeruginosaKuetzing emend. Elenkin crusts estimated to be 5–6 months old from the shore of Lake Mokoan were toxic by mouse bioassay (LD100100–140 mg dry wt/kg mouse). Fresh bloom material from the lake was also highly toxic (LD10025–35 mg dry wt/kg mouse). Microcystin high performance liquid chromatography (HPLC) profiles of the crust and fresh material were very similar, with 24 compounds having UV spectra consistent with microcystin LR. Five of the major microcystins were purified and analysed by electrospray/mass spectrometry. The molecular weights of these microcystins [910, 924, 982, 982 (two compounds), and 986] do not correspond with known microcystins. All five compounds were hepatotoxic to mice with LD100values ranging from 85 to 140 μg microcystin/kg mouse). Total microcystin contents (expressed as microcystin LR aquivalents) determined by HPLC correlated with the mouse bioassay analyses (crust 2.1 μg microcystin/mg dry wt; fresh 4.1 μg microcystin/mg dry wt). These results suggest that microcystin is protected from degradation while encapsulated within the driedMicrocystiscrusts. Leaching experiments demonstrated that re‐wetting of the crust material leads to rapid release of microcystins into the surrounding water. These observations have important management implications for lakes and reservoirs where crusts of cyanobacterial material form on the shoreline. ©by John Wile

ISSN:1053-4725    

DOI:10.1002/tox.2530100104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe newly developed 1‐h enzymatic inhibition bioassay (Fluotox) was applied to toxicity testing with the larvae of the brine shrimpArtemia.The method consists of visual observation of in vivo inhibition of an enzymatic process using a fluorigenic enzyme substrate. The 1‐h Fluotox test and the conventional 24‐ and 48‐h LC50toxicity tests were conducted in parallel on 8 different organic and inorganic chemicals. A good correlation was found between the 1‐h EC50and the 24‐ and 48‐h LC50data withr2s of 0.94 and 0.93 for each respective regression. Addition of the enzyme substrate did not influence the toxicity of the chemicals in the 24‐ and 48‐h tests. The repeatability of the Fluotox test compares favorably with that of the conventional 24‐h acute test; coefficients of variation (CV) ranged from 8 to 34% and from 1 to 39%, respectively.Investigations on the applicability of the Fluotox procedure for testing in brackish waters revealed that lowering the salinity from 35 to 15 ppt did not affect the fluorescence and mortality responses in the controls.The same decrease in salinity had no significant influence on the 1‐h EC50s except for NaLS and acetic acid. The ratio between the 1‐h EC50s at 35 and 15 ppt varied from 0.46 to 2.18 depending on the chemical.However, the same decrease in salinity significantly influenced (p<0.05) the 24‐h LC50s (except NaPCP) and the 48‐h LC50(except formaldehyde). In general, the ratio of the LC50values obtained at 35 and 15 ppt varied from 0.30 to 2.21 and from 0.48 to 2.53 for the 24‐ and 48‐h exposures, respectively.In view of several inherent advantages such as rapidity, experimental simplicity, low cost of performance, and the use of dry cysts as biological starting material (which eliminates the maintenance of live stock culture) the 1‐hArtemiaFluotox test offers promising potential for numerous ecotoxicological appli

ISSN:1053-4725    

DOI:10.1002/tox.2530100105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractToxicity testing of sediment samples from the Rio Santiago and its main tributaries was performed using a battery of tests that included the ECHA dipstick biocide monitor, the MetPad test, the lettuce seed germination and the root elongation test, the nematode test, spot plate test, and the SOS Chromotest. Assessment was carried out on organic extracts, pore water, and direct sediment. Results of bioassays showed toxicity sources from tributaries and canals flowing into the river and areas being degraded by insults from industrial spills. ©by John Wiley&Sons, Inc

ISSN:1053-4725    

DOI:10.1002/tox.2530100106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThe bacterial bioluminescence assay is widely used to estimate chemical cytotoxicity. This assay is performed most often by using luminescent bacteriaVibrio fisheriNRRL‐B‐11177 (earlier cited asPhotobacterium phosphoreumNRRL‐B‐11177) as a test organism. In this work we have used cloned gram(+) and gram(−) bacterial strains for the evaluation of chemical toxicity. Two types of luciferase genes were used as reporter genes, one of which was ATP‐dependent eukaryotic luciferase fromPyrophorus plagiophthalamusand the other was FMN‐dependent bacterial luciferase fromVibrio harveyi. These cloned strains were used to evaluate the effects of differences in cell wall structures in the bioluminescence cytotoxicity test using small molecular weight toxic chemicals as model compounds. The strains were found to have remarkably similar behavior and sensitivity toward test toxicants regardless of rather different kinds of membrane structure. However, the eukaryotic luciferase was found in every aspect more useful in toxicity tests than bacterial luciferase mainly because of increased sensitivity and ease of operation. The general behavior of the light emission is described and several aspects affecting the usefulness of the strains are discussed. ©by John W

ISSN:1053-4725    

DOI:10.1002/tox.2530100107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractA biotesting method for the assessment of acute sublethal toxicity to charophyte cells ofNitellopsis obtusawas developed and applied for the study of Vilnius and Visaginas wastewaters (WW). This computer‐assisted testing procedure was based on the recording of the electrophysiological response of up to 16 single algal cells simultaneously. Membrane parameters of living cells were measured according to the K+‐anaesthesia method modified for multichannel recording with extracellular electrodes. Concentration‐dependent monotonical decrease of cell resting potential, induced by toxic WW action, was used to determine an effective concentration (EC) values. A multistep time‐saving procedure, when the cell group was exposed to subsequent treatment with increasing WW concentrations (30 min per treatment), proved to be adequate for biotesting. The ECs obtained by this procedure were in good agreement with those obtained alternatively by undertaking one‐step testing (i.e., 60 min exposure per concentration per cell group). The relative sensitivity of the cellular electrophysiological response, as a toxicity end point, was confirmed by comparing it with lethal concentration (LC) responses in 96‐ and 192‐h exposure tests conducted on the sameN. obtusacells. For Vilnius WW samples taken on different dates, the EC 50 sranged from 27 to 46% WW and corresponded to 96‐h LC 50 sof 28–50% WW. In contrast, Visaginas WWs sampled before and after chlorination showed no toxic effect either at the membrane or whole cell level.

ISSN:1053-4725    

DOI:10.1002/tox.2530100108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper reviews published studies on polychlorinated dibenzo‐p‐dioxins and polychlorinated dibenzofurans that are relevant to an assessment of their aquatic ecotoxicology. The available data suggest that laterally substituted congeners containing altogether 4,5, or 6 chlorine atoms are highly toxic, particularly to the early life stages of fish, with reported effect concentrations in the ng L1range. These congeners are also the most readily bioaccumulated.An aquatic toxicity threshold concentration of 0.011–0.038 ng L−1, applicable to natural ecosystems, was determined for 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (or for mixtures of congeners expressed as 2,3,7,8‐TCDD equivalents). This threshold corresponds to the no observed effect concentration/lowest‐observed effect concentration determined for mortality, growth, and behavioral effects seen in rainbow trout early life stages, exposed to 2,3,7,8‐TCDD in a flow‐through system over a 28‐day period, followed by 28 days of depuration.An investigation was also made into the potential for using mammalian‐derived toxic equivalency factors (TEFs) in aquatic ecosystems. This revealed that such an approach may underestimate the aquatic toxicity of some congeners, and that the use of organism‐specific TEFs may be more appropriat

ISSN:1053-4725    

DOI:10.1002/tox.2530100109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:1053-4725    

DOI:10.1002/tox.2530100110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY

ISSN:1053-4725    

DOI:10.1002/tox.2530100101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1995

数据来源: WILEY