摘要:

AbstractA large number of different chemical compounds can be found in the air of densely populated animal production houses. These compounds may influence animal performance and health. Although knowledge of the biological activity of such compounds is limited in these situations, bioassays with animals are expensive, complicated to perform and evaluate. At the same time there is an increasing interest in simple and reliable test methods avoiding the use of laboratory animals. Microbial short‐term assays offer many advantages, particularly for screening purposes.The recently introduced Microtox assay was used to test the toxicity of eight single air contaminants, 13 two‐compound mixtures, and some extracts from aerosols and dust from a confined pig fattening house. p‐Cresol was the most toxic with an EC50(15 min) value of 0.015 mM followed by m‐cresol (0.074 mM), butyric acid (0.115 mM), dimethylamine (0.156 mM), formaldehyde (0.25 mM), phenol (0.46 mM), butanol (32 mM), and acetone (258 mM). The coefficients of variation for five replicates of these compounds ranged from about 5% (m‐cresol) to 24% (dimethylamine).The two‐compound mixtures showed mainly synergistic or antagonistic effects. The investigation of the aerosol extracts showed that increasing aerosol amounts also increase the necessary dilution ratio to reach the EC50(15 min) value. Futhermore, it was observed that the dust extract can stimulate the growth ofPhotobacterium phosphoreum(as determined by plate counts) although the bioluminescence is ceased. Apparently the inhibition of the light output of the bacteria is not necessarily accompanied by a loss o

ISSN:0884-8181    

DOI:10.1002/tox.2540020102

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

年代:1987

数据来源: WILEY

摘要:

AbstractThe effects of eight organic and eight inorganic compounds on light emission by two cell‐free bioluminescent systems were compared to the effects of these substances on light emission by whole cells ofPhotobacterium phosphoreum(Microtox® strain). Crude luciferase preparations from the firefly (Photoniuspyralis) andVibrio (Photobacterium) fischeriwere exposed to the toxicants at or near the Microtox EC50values for 0.25, 5, or 15 min and then reacted with the necessary reagents for luminescence (ATP for the firefly reaction; NADH, FMN and n‐decylaldehyde for the bacterial extract). The light emission values, relative to controls, were then compared to those obtained after exposure ofP. phosphoreumcells to the toxicants for the same duration. The three systems were found to differ in both response time and sensitivity. The firefly extract was found to be most sensitive to inorganics while whole cells ofP. phosphoreumwere most sensitive to organics after 0.25 min of exposure. However, after 5 and 15 min both systems were nearly equivalent in their sensitivity to the test toxicants. TheV. fishcericell extract was found to be extremely sensitive to three of the inorganics tested at 0.25 minutes, but was either unaffected or stimulated by the remaining inorganic and organic compounds at all times examined. Our results indicate that the sensitivity of detection of certain toxic compounds may be optimized by selection of a particular luminescent sy

ISSN:0884-8181    

DOI:10.1002/tox.2540020103

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

年代:1987

数据来源: WILEY

摘要:

AbstractA firefly luciferase bioluminescent assay of bacterial adenosine triphosphate (ATP) was used to measure the toxic effects of metal ions on six bacterial genera isolated from two geographically different marsh treatment systems. The toxicity of eleven different metals, as well as metal mixtures, was monitored using the agar plate test and the resazurin reduction test in addition to measurement of intracellular ATP. All the organisms surveyed tended to be sensitive to much lower concentrations of metals when the metals were present in mixtures. Isolates from a marsh system constructed on normal soil exhibited lower metal resistance patterns than organisms isolated from a marsh built on mine tailings. The intracellular ATP assay appeared to be the most sensitive method of determining the viability of bacterial cells following metal treatment.

ISSN:0884-8181    

DOI:10.1002/tox.2540020104

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

年代:1987

数据来源: WILEY

摘要:

AbstractToxic inhibition of three communities of filamentous microorganisms by chlorine and hydrogen peroxide was investigated in relation to the total suspended solids concentration of bulking acitvated sludges. The filament communities studied were dominated by type 1701,Sphaerotilus natans, and the combination of type 021N andThiothrixspp., respectively. Activity of filamentous and gross biomass was assessed separately using the malachite green‐INT (MINT) test. The effectiveness of toxicants was characterized in terms of the concentration required to inhibit 50% of microbial dehydrogenase activity (IC50). IC50s were found to be proportional to total suspended solids concentration. Values for filamentous biomass were generally lower than those for gross biomass. Relative sensitivity (ratio of gross IC50to filamentous IC50) did not vary significantly over the practical range of total suspended solids concentraton. This parameter was unaffected by the nature of the toxicant inS. natansand type 021N/Thiothrixdominated sludges, but was toxicant specific in type 1701 dominated sludge. Overall,S. natansand type 1701 were the least sensitive of the filament types studied. Bulking caused by these organisms has been successfully cured by toxicant addition in numerous past instances. It is therefore expected that type 021N,Thiothrix, and most other types of filamentous bulking can also be controlled by this techniqu

ISSN:0884-8181    

DOI:10.1002/tox.2540020105

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

年代:1987

数据来源: WILEY

摘要:

AbstractAccumulation of109Cd byPs. fluorescenshas been investigated using the metabolic inhibitors: 1 mM dinitrophenol (DNP) and 100 μM NN′dicyclohexylcarbodiimide (DCCD). Although bacterial uptake of cadmium was reduced by DNP and DCCD, the ability of these inhibitors to complex109Cd was thought to be the cause, rather than a reduction in metabolic activity. This was substantiated by the absence of effects due to temperature and nutrient conditions. Experiments undertaken with Ca, Mg, Zn, and Mn ions have proven the competitive action of Ca, Mg, and Mn ions on cadmium upta

ISSN:0884-8181    

DOI:10.1002/tox.2540020106

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

年代:1987

数据来源: WILEY

摘要:

AbstractNoting that the inducibility of samples tested with the SOS Chromotest increased with increasing colour development time, a slightly modified Chromotest procedure was developed and applied to six sediment samples from Prince Edward Island. The samples tested by this newly developed short‐term genotoxicity test showed weak inducibility expressed by the SOSIP—SOS Inducing Potency. Five of the six samples were activated by the addition of S‐9 fraction, commonly used with the Ames/Microsome test. Only one of the samples showed toxic activity by the Microtox

ISSN:0884-8181    

DOI:10.1002/tox.2540020107

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

年代:1987

数据来源: WILEY

摘要:

AbstractNumerous federal regulations are concerned with the release or potential release of chemicals to the environment. Testing that has been proposed under the Toxic Substances Control Act for microbiological effects and persistence has certain limitations. Improved and extremely sensitive procedures are now available to assess chemical toxicity to microorganisms and persistence at environmentally realistic concentrations. This paper discusses these aspects and presents preliminary data for a novel method based on thymidine uptake which offers promise as a routine sensitive assay for the effects of chemicals on biomass, and vice versa. The method has been shown to provide useful data about the persistence of chemicals at realistic environmental concentrations.

ISSN:0884-8181    

DOI:10.1002/tox.2540020108

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

年代:1987

数据来源: WILEY

摘要:

AbstractOutbreaks of fish diseases have been reported in many parts of the world. The outbreaks are difficult to control. During December 1982 and March 1983, there were severe outbreaks of fish disease in Thailand. A study on the presence and inactivation of harmful toxins, i.e., cytotoxin and hemolysin, by heat, salt and gastric pH was undertaken. Cytotoxin and hemolysin were detected in all diseased snakehead fish (Ophicephalus striatus) homogenates.Aeromonas hydrophilaF 588 isolated from the diseased snakehead fish also produced cytotoxin and hemolysin. No detectable cytotoxic or hemolytic activity was found in the fish homogenates orA. hydrophilaF 588 cell suspensions after heating at 100°C for 5 minutes or autoclaving at 121°C for 15 minutes at 15 lb/in.2Cytotoxic activity remained positive in all concentrations (0% to 30% W/V) of NaCl. However, no cytotoxin could be detected when the pH of the samples was 2.0. There was a 55% decrease in hemolytic activity whenA. hydrophilaF 588 was incubated in 30% NaCl for 1 month at 30°C. Furthermore, there was a 50% decrease in the activity when the pH of the samples was 2.0. Hence, the diseased fish is safe for consumption if it is heated for 5 minutes at 100°C. However, it is unsafe to consume unheated salt‐fermented

ISSN:0884-8181    

DOI:10.1002/tox.2540020109

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

年代:1987

数据来源: WILEY

ISSN:0884-8181    

DOI:10.1002/tox.2540020110

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

年代:1987

数据来源: WILEY

ISSN:0884-8181    

DOI:10.1002/tox.2540020111

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

年代:1987

数据来源: WILEY