摘要:

AbstractFollowing a previous study on the biodegradation of pentachlorophenol (PCP) (100 mg L−1) by Zygomycetes, other taxonomic groups (Ascomycetes, Basidiomycetes, and Yeasts) have been investigated in relation to their ability to produce extracellular phenoloxidases. Ascomycetes gave heterogeneous results since disappearance of PCP occurred both in phenoloxidases‐producing and non‐producing strains. Basidiomycetes were high producers of phenoloxidases and showed a moderate depletion of PCP. Yeasts degraded PCP very poorly and did not produce phenoloxidases. No correlation was found between phenoloxidases production and PCP depletion. ©1994 by John Wiley&Sons

ISSN:1053-4725    

DOI:10.1002/tox.2530090102

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

年代:1994

数据来源: WILEY

摘要:

AbstractAssessing the interactive toxic effect of chemicals in the environment is becoming a matter of increasing public focus on and concern with ecotoxicological aspects. The purpose of this study is to find the relationship between an interactive toxic effect and distribution of heavy metals in algal cells. The green algaChlorella ellipsoideaGernec(IAMC‐27) was cultured for 6 days in the presence of cadmium and/or chromium. Algal cells were divided into 4 fractions by centrifugation after the cells were disrupted using a French press. The amounts of the metals in each fraction were determined.The interaction effect between the two metals on algal growth was investigated. The amount of one metal taken up in the cells and the growth inhibition rate increased with the concentration of metals in the medium. The amount of one metal in the cells was increased due to the presence of the other metal. Accordingly, the growth inhibition rate also increased. The amounts of Cd accumulated in the soluble fraction and in the membrane fraction of algal cells were 50 and 20%, respectively, of the total amount in the cells. The presence of Cr changed the Cd concentration in both fractions to 40%. The amount of Cr accumulated in each fraction was almost the same in the absence of Cd. The amount of Cr accumulated in the cell wall fraction rose to 90% after 3 days of exposure and it stayed as high as 50% even at the end of the six‐day study period in the presence of Cd. It was assumed that the presence of one metal influenced the distribution of the other metal in the cells, which resulted in the synergistic toxic effect. ©1994 by John Wiley&Sons,

ISSN:1053-4725    

DOI:10.1002/tox.2530090103

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

年代:1994

数据来源: WILEY

摘要:

AbstractMaize samples were obtained from different locations—namely Aba, Abakaliki, Afikpo, Okigwe, and Owerri—all in southeast Nigeria. Twelve mold species of the generaAspergillus, Penicillium, Cladosporium, Alternaria, Fusarium, andAcremonium (Cephalosporium)were isolated. The presence of aflatoxin B1was detected in 80% of the samples by the characteristic blue fluorescence that appeared on silica gel coated thin layer chromatography plates when viewed with a long‐wave ultraviolet radiation source alongside an aflatoxin standard. Eight isolates of theAspergillus flavusgroup obtained from the maize samples were tested for aflatoxin production. Natural medium (maize) at 26°C and moisture content adjusted to no less than 20% was used. Aflatoxin was produced to some degree by 87.5% of the isolates. There was no aflatoxin production at a market moisture content of 5.4% and temperature of 25, 30, and 35°C. However, at 26°C and increased moisture contents of 22.3–24.9%, varying amounts of aflatoxin were produced. ©1994 by John Wiley

ISSN:1053-4725    

DOI:10.1002/tox.2530090104

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

年代:1994

数据来源: WILEY

摘要:

AbstractConventional parameters for assessing effluent quality like the 5‐day biological oxygen demand, (BOD5), total suspended solids (TSS), and coliforms take from one to five days before the tests are completed. Simple, rapid, economical, and reliable methods to determine wastewater quality parameters are essential for the effective control of effluent discharges and the monitoring of process performance. If disinfection is necessary, these rapid methods may be used to quickly estimate the disinfection requirements and to ensure that the final effluent quality is microbiologically adequate. This is especially applicable to the sequencing batch reactor system, which treats wastewater in a batchwise manner. The 6‐h coliphage, 3‐h chemical oxygen demand (COD) and 1/2‐h total organic carbon (TOC) tests have been identified as rapid tests. Being microbiologically related, the coliphage test was shown to have a good degree of correlation with coliform levels in the effluent. Predictions of coliform numbers may be made by enumeration of the phages. The COD was also correlated and shown to produce a quick estimate of the total BOD5, TSS, and coliform values. Although the TOC test is based on the dissolved portion of the effluent, it may also be used as a rapid estimation of the total BOD5, TSS, and coliform values. ©1994 by John Wiley&So

ISSN:1053-4725    

DOI:10.1002/tox.2530090105

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

年代:1994

数据来源: WILEY

摘要:

AbstractA third study on the biodegradation of pentachlorophenol (PCP) (100 mg L−1) by micromycetes was done with 784 strains of Deuteromycetes cultivated in liquid synthetic medium. The disappearance of PCP after 5 days of cultivation was compared with POx production. Mean PCP depletion was 56% for Agonomycetales, 60% for Coelomycetes, 51% for Dematiaceae, 52% for Mucedinaceae (other thanAspergillusandPenicillium), 56 and 57%, respectively, forAspergillusandPenicillium, and 42% for Tuberculariales. Although some genera gave homogeneous results (Ascochyta, Aspergillus, Coniothyrium, Penicillium), a great variability was observed as well in PCP depletion as in POx production, reflecting the heterogeneity of this artificial taxonomic group. With a few exceptions, correlation between POx production and PCP disappearance was low or nonexistent. Another factor, probably not enzymatic, could be involved. ©1994 by John Wiley&Sons, In

ISSN:1053-4725    

DOI:10.1002/tox.2530090106

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

年代:1994

数据来源: WILEY

摘要:

AbstractGenuine needs for rapid, simple, and cost‐efficient biotesting procedures to screen an ever‐increasing number of chemicals and environmental samples are making the search for such assays a constant endeavor. With respect to genotoxicity screening, we compared, in this study, the performance of two novel assays (Vibrio fischeriM169 Mutatox™ assay and theEscherichia coliPQ37 SOS Chromotest kit assay) with two well‐established Ames testing procedures (plate incorporation and fluctuation assays). Testing material included 14 chemicals (10 potentially directly acting and 4 indirectly acting compounds) reflecting different chemical classes (2 inorganics, 2 pesticides, 2 halogenated hydrocarbons, 2 alkylating agents, 2 aromatic amines, 1 chlorophenol, and 3 polycyclic aromatic hydrocarbons). Comparative assessment criteria included (1) interprocedural agreement in detecting presence or absence of genotoxicity, (2) accuracy in being able to recognize animal (non)carcinogens, and (3) sensitivity (detection of lowest actively genotoxic concentration). In terms of qualitative responses, both the SOS Chromotest (86% agreement) and Mutatox assays (93% agreement) were good predictors of the Ames testing mutagenicity. For their capability to correctly discriminate between (non)carcinogens, accuracy was 82% (9 of 11 chemicals) for Mutatox, 73% (8 of 11 chemicals) for Ames testing, and 64% (7 of 11 chemicals) for the SOS Chromotest. In general, theSalmonella‐based assays proved more sensitive (6 times out of 9 chemicals) than the Mutatox (3 times out of 9 chemicals) and the SOS Chromotest (never more sensitive). Overall, this study demonstrates reliable performances by both the SOS Chromotest and Mutatox for chemical genotoxicity screening when results are referenced to the well‐validated Ames assay. Although additional comparative data with other chemicals will be required, it appears likely that these more practical and cost‐efficient procedures can be presently useful to screen genotoxic activity of various xenobiotics and environmental samples. ©1994 by John Wi

ISSN:1053-4725    

DOI:10.1002/tox.2530090107

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

年代:1994

数据来源: WILEY

摘要:

AbstractSediment and water samples were taken from five sites in Thunder Bay, one upstream (control) and four downstream locations from a bleached kraft pulp mill. Biochemical effects were examined by estimating the carbohydrate content and enzymatic activities of alkaline phosphatase, cellulase, and dehydrogenase in the sediment. Genotoxicity and toxicity of sediment and water were assessed by the SOS Chromotest, although liver microsomal samples were not used to screen for progenotoxic substances. Sediment and water samples were also analyzed for resin and fatty acids, which indicate the degree of effluent contamination. Significant differences in enzyme activity and carbohydrate content were found between sites. Genotoxic values were obtained for downstream water samples for most of the sampling months, however, the sediment only showed genotoxic activity in the July and October samples. The study showed that there are substances causing genotoxic and biochemical effects in the Kaministiquia River, Ontario. ©1994 by John Wiley&Sons, Inc.

ISSN:1053-4725    

DOI:10.1002/tox.2530090108

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

年代:1994

数据来源: WILEY

摘要:

AbstractSpecific, straightforward, and rapid procedures are required for the detection, identification, and quantification of the potent low molecular weight toxins that are produced by blooms and scums of cyanobacteria (blue‐green algae) in waterbodies.Use of the Microtox bioluminescence assay and the brine shrimp (Artemia salina) has been advocated for the initial screening of cyanobacterial blooms for microcystin hepatotoxins. Inhibition of bacterial luminescence in the Microtox assay and brine shrimp mortality were determined with microcystin‐containing and nonmicrocystin‐containing cyanobacteria.Extraction and fractionation of test samples was undertaken to select and isolate microcystincontaining fractions and reduce interference from other fractions. Maximal inhibition of bacterial luminescence in the Microtox assay occurred with fractions fromMicrocystisstrains and anAnabaenabloom that did not contain microcystins. By contrast, the bioassay of fractions using brine shrimps correlated with the distribution of microcystin‐LR in the fractionatedMicrocystisextracts. ©1994 by John Wiley&So

ISSN:1053-4725    

DOI:10.1002/tox.2530090109

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.2530090110

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.2530090111

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

年代:1994

数据来源: WILEY