摘要:

AbstractWe tested the ability of a 0.04‐μm nylon membrane filter to remove viral agents (influenza A virus, 80–120 nm; phage T1, 50–150 nm; and phage PP7, 25 nm) from the following media: ultrapure water (UPW), Dulbecco's modified Eagle minimum essential medium (DMEM), gelatin phosphate (GP), DMEM with 10% (DMEM‐10) fetal bovine serum (FBS), and 100% FBS. When challenged with at least 3.0 × 107plaque‐forming units/mL, no influenza A virus was detected downstream of the filter with any of the fluids tested. The titer reduction (Tr) was determined using the equation:.Higher concentrations of phage T1 were removed from UPW (Tr= 1.6 × 106) and DMEM (Tr= 1.1 × 106) than from GP (Tr= 9.3 × 103), DMEM‐10 (Tr= 1.5 × 102), and 100% FBS (Tr= 2.4 × 102). Phage PP7 was removed in significant numbers only in ultrapure water (Tr= 8.5 × 104). The results indicate that adsorption enhanced the titer reduction in fluids containing low levels of protein. The titer reduction in DMEM‐10 and 100% FBS may reflect the sieving properties of the 0.04‐μm filter. As expected, a much smaller Tr was observed in the filtrate of the 0.2‐μm filters, compared to the 0.04 μm filters. In contrast to the 0.04‐μm filter, no increase in Tr was detected when the 0.2‐μm filters were challenged with virus diluted in UPW compared with virus diluted in GP. These results suggest that the 0.04‐μm filter has greater adsorptive properties than the 0.2‐μ

ISSN:1053-4725    

DOI:10.1002/tox.2530090302

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

年代:1994

数据来源: WILEY

摘要:

AbstractWe have developed biomarkers of sublethal toxicity in the freshwater rotiferBrachionus calyciflorusbased on the reduction of enzyme activity. Esterase and phospholipase A2 activity was quantified in single rotifers using image analysis and a fluorescence detection system. Esterase activity was localized in the gut and phospholipase A2 activity in the corona of females. Quantitation of enzyme activity demonstrated that toxicant stress reduced activity in a dose‐dependent manner. Concentration‐response relationships are described for 10 compounds representing a variety of toxicant classes and NOECs are reported. Esterase and phospholipase A2 activities were generally less sensitive end points than reproduction NOECs, but usually were more sensitive than LC50s. Since in vivo enzyme activity can be assessed in 1 h, these biomarkers will be useful where rapid results are important. The cost of performing in vivo enzyme inhibition tests is substantially less than traditional whole animal tests because these require three times more person‐hours to execute. Obtaining test animals by hatching cysts, their sensitivity to toxicants, and the rapid results make the rotifer esterase and phospholipase A2 tests good candidates for inclusion in a test battery for rapid toxicity assessment. ©1994 by John Wiley&Sons

ISSN:1053-4725    

DOI:10.1002/tox.2530090303

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe impact of graded concentrations (5, 10, 15, and 20 mg L−1) of Omega Chrome Red ME, a common dye used in woollen, carpet, and textile industries, on protein production, pigment content, and photosynthetic oxygen evolution in a diazotrophic cyanobacteriumNostoc muscorumISU, was studied. All concentrations were found to be inhibitory, with lower concentrations (5 mg L−1) producing a negligible effect, while higher concentrations produced a dramatic decrease in the parameters observed. The highest concentration of dye tested (20 mg L−1) resulted in a decrease in protein, chlorophyll a, phycocyanin, and carotenoid content of 82.20, 82.69, 46.20 and 41% of control, respectively. Photosynthetic oxygen evolution was decreased by 83.50% of control at the highest dye concentration. ©1994 by John Wiley&Sons

ISSN:1053-4725    

DOI:10.1002/tox.2530090304

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

年代:1994

数据来源: WILEY

摘要:

AbstractAccumulation of cadmium, lead, and mercury in the tissues of the musselMytilus edulis planulatusL. from the Derwent Estuary, Hobart, Australia was linear over a range of metal concentrations in the ambient water, provided that the condition index of the mussels (meat weight/shell weight) indicated that the organisms were not under environmental stress. Polynomial regression analysis of accumulation rates against ambient concentrations of the respective metals in the water column in the vicinity of the mussels showed that the relationships depended upon the physical speciation of the metals (i.e., filtrable vs particlate metals). The results indicated that it may be feasible to use metal accumulation rates in mussels to provide broad‐based estimates of metal concentrations in marine waters, provided that the organisms have been calibrated under conditions similar to those prevailing at the proposed monitoring sites. ©1994 by John Wiley&Sons, In

ISSN:1053-4725    

DOI:10.1002/tox.2530090305

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe effects of chromium (or chromate, as supplied by CrO3) on a pentachlorophenol‐degradingFlavobacteriumsp. (ATCC 53874) were examined in a liquid bacterial growth medium. Cr6+concentrations ⩾ 5.0 μg mL−1caused the complete inhibition of bacterial growth. The EC25, EC50, and EC75calculated after 96 h of incubation were 0.44, 1.44, and 3.82 μg mL−1, respectively. Cr6+caused an irreversible reduction in total cell yield during the 21‐day incubation. Cr6+also elicited an increase in the lag time recorded before there was measurable pentachlorophenol (PCP) degradation by this bacterium. There was also an increase in the overall time required for complete degradation of PCP to nondetectable levels. A similar response was noted with all PCP concentrations examined from 10 to 100 μg mL−1. However, a more pronounced response occurred at the lower PCP concentrations. The significance of these data relative to the in situ use of PCP‐degrading bacteria for site bioremediation is outlined. ©1994 by John

ISSN:1053-4725    

DOI:10.1002/tox.2530090306

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe effects of nickel and methyl‐parathion were studied in subinhibiting concentrations (40 and 62.5 μg/mL, respectively) on the levels of cellular peroxidation inEscherichia coli.These effects were evaluated using the thiobarbituric acid (TBA) test and the determination of lipofuscin‐like substances. Both toxicants caused an increase in cellular peroxidation levels, although at the concentrations used, nickel was shown to be a better inducer than methyl‐parathion. The TBA test gave more significant differences than the determination of lipofuscin‐like substances when the control cultures were compared to those containing the toxicant. This finding reveals that the TBA test could be used as a toxicity marker inE. colifor the development of ecotoxicity biotests. ©1994 by John Wiley&S

ISSN:1053-4725    

DOI:10.1002/tox.2530090307

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe effect of treatments with 2,4‐dichlorophenoxyacetic acid (2,4‐D) on fungal propagules in man‐made freshwater ponds was studied as part of a larger investigation into the effects of the herbicide on the ponds' ecology and chemistry.Myriophyllum spicatumwas planted in the ponds as a target plant; the ponds were allowed to stabilize before being treated with dimethylamine (DMA) and butoxyethylester derivatives of 2,4‐D (1 mg/L). Although the 2,4‐D treatments were highly toxic toM. spicatumin the ponds (B. F. Scott et al., 1985a) they did not have a clear effect on fungal propagule levels in either the water column or sediment, which indicates the absence of a primary effect. The mean levels of molds and “total fungi” in both pairs of treated ponds, and of yeasts in the DMA‐treated ponds, tended to be depressed relative to the control ponds, for up to 114 days after treatment. That observation was reinforced by plots of the accumulated differences between the treated and control ponds. The differences between the mean fungal levels in the control and treated ponds were erratic, however, and the study's design did not permit a thorough statistical analysis of the data, although a multiple comparison test detected some differences (p<0.05) between propagule levels, particularly molds, in the treated and control ponds. If real, the trends were probably a result of unidentified secondary effects of the pond treatments. The results imply that applications of 2,4‐D to aquatic vegetation at realistic rates do not drastically affect fungal propagule levels in the water column or sediment. ©1994 by Joh

ISSN:1053-4725    

DOI:10.1002/tox.2530090308

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe hepatic carboxylated porphyrin profile was studied in whitefish exposed to bleached kraft pulp mill effluent (BKME). The distribution of the porphyrins was different between the samples from the BKME and the reference site, and fish exposed to BKME contained higher amounts of highly carboxylated porphyrins (HOP). The ratios of HCP to protoporphyrin, and coproporphyrin to protoporphyrin, were also significantly different between the two groups. In addition, the cytochrome P‐450 activity, liversomatic index, and gonadosomatic index were measured and compared with the prophyrin profile. The results suggest that BKME could inhibit porphyrinogen decarboxylases, and the porphyrin profile is useful as a biochemical indicator for identification of BKME exposure. ©1994 by John Wiley&Sons, In

ISSN:1053-4725    

DOI:10.1002/tox.2530090309

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

年代:1994

数据来源: WILEY

ISSN:1053-4725    

DOI:10.1002/tox.2530090310

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

年代:1994

数据来源: WILEY

ISSN:1053-4725    

DOI:10.1002/tox.2530090311

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

年代:1994

数据来源: WILEY