bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of physicochemical parameters on the microtox test response
Authors: Vasseur P. , Bois F. , Ferard J. F. , Rast C. 
Published: October 2006

AbstractToxicity studies are generally conducted with single chemicals under standardized conditions. Yet results with the same substances can be different if antagonistic or synergistic interactions occur with the test medium constituents. In fact the toxic response of various chemicals seems highly dependent on temperature, contact time, salinity, buffering substances and water hardness.As Microtox test has previously been used to assess the toxicity of pure chemicals and complex effuents, it is interesting to study how some physico‐chemical interactions can modulate the response of the luminescent bacteria in this system.In the present investigation, the effects of the test temperature and the role of pH, buffers, hardness and salinity were studied for different times of exposure of the Microtox bacterial reagent to various inorganic and organic compounds including cadmium, zinc, pentachlorophenol and benzene. The results indicated that physicochemical parameters must be considered when analyzing Microtox data of complex effuents or mixtures of chemicals.
The toxicity and mutagenicity of n‐nitroso compounds in sarcina lutea and salmonella typhimurium
Authors: Lin Jen‐Kun , Horng Tzyy‐Show 
Published: October 2006

AbstractMutants of Salmonella typhimurium have been used as tester strain in assessing the mutagenicity of various compounds. The revertants arising from the backmutation of these mutants by tested chemicals were counted and used as the measure of mutagenicity. Several N‐nitroso compounds were found to be insensitive to Salmonella system. In searching for a new microbial system for evaluating the toxicity and mutagenicity of N‐nitroso compounds, we found that the Grampositive coccoid organism Sarcina lutea is responsive to the challenge of these compounds. The wild type of Sarcina lutea is characterized by its gold yellow colony. On treating with direct‐reacting N‐nitroso compounds, Sarcina lutea produces several groups of mutants with different color of colonies such as white, pink and pale‐yellow. It seems that the mutants result from the induced mutation of the genes responsible for the synthesis of carotenoids. Several newly synthesized N‐nitroso compounds including N‐nitrosophenacetin, 2‐nitro‐N‐nitrosophenacetin, N,N′‐dimethyl‐N‐nitrosourea and nitrosated 2‐carboline derivatives were tested on this newly developed system. For the purpose of comparison, the mutagenicity of these compounds were also tested on several Salmonella typhimurium strains such as TA 97, TA 98, TA 100, TA 1538, TA 1537, and TA 1535.
Practical and theoretical aspects of the DCB assay for carcinogenic and other genotoxic agents
Authors: Kubinski H. , Kubinski Z. O. 
Published: October 2006

AbstractThe DNA‐cell binding (DCB) assay grew from our early studies demonstrating that in the presence of carcinogenic chemicals, radioactively labeled nucleic acids attached strongly to isolated cellular membranes and to intact prokaryotic and eucaryotic cells. A survey of over 300 chemicals revealed that this test is capable of correctly predicting carcinogenic potential in more than 95% of cases. Recently we began using formaldehyde‐treated Escherichia coli indicator cells and noted that the accuracy of prediction and the sensitivity of the test are even greater. For example, a class of noncarcinogenic, intercalating agents that showed as false positives in the original study, scored negative in this modified version of DCB test. This assay has several advantages over other rapid tests for genotoxicity, including simplicity, rapidity, economy, and reproducibility. As demonstrated by our studies on a number of diverse products, it is especially suitable for analyzing industrial and other environmental chemicals and their mixtures. The increased DNA‐cell binding is due to a property shared by most, if not all, carcinogenic agents—their ability to produce macromolecular adducts between proteins and nucleic acids, as well as inter‐ and intramolecular complexes in DNA. The latter class of adducts is responsible for inducing chromosomal transposition‐like events that we observed in a separate set of experiments using transformation of Bacillus subtilis for measuring distances between genetic markers. In these experiments markers were stably transferred to a different position on the chromosome as the result of DNA‐exposure to an ultimate carcinogen, N‐acetoxy N‐acetyl‐aminofluorene. If, as many investigators believe, the specific chromosomal translocations are the cause of neoplasia, the high predictive potential of the DCB test may be due to its capability to measure the production of specific macromolecular complexes.
The toxicity of betel nut extract determined by inhibition of microbial dehydrogenase activity
Authors: Koontongkaew Sittichai , Thaweboon Boonyanit , Tungtrongchitr Rungsunn 
Published: October 2006

AbstractDimethyl sulfoxide extracts of betel nut (100g/L) and betel leaf (100g/L), and methanol and water extracts of betel nut (100g/L) were found to inhibit dehydrogenase activity of Bacillus subtilis. In contrast betel nut (100g/L) extracted by petroleum ether showed no inhibitory effect. Thin layer chromatography, ultraviolet spectroscopy and total polyphenols estimation indicated that betel nut contained large amounts of polyphenols. On the basis of toxicity assessment, the results implied that betel nuts and betel leaves contained a hydrophilic element which was toxic to living cells.
Cytotoxin and hemolysin in diseased fish during epidemic outbreaks
Authors: Laohaviranit Laddavan 
Published: October 2006

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 hydrophila F 588 isolated from the diseased snakehead fish also produced cytotoxin and hemolysin. No detectable cytotoxic or hemolytic activity was found in the fish homogenates or A. hydrophila F 588 cell suspensions after heating at 100°C for 5 minutes or autoclaving at 121°C for 15 minutes at 15 lb/in.2 Cytotoxic 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 when A. hydrophila F 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 fish.
Cultured fish cells for the ecotoxicity testing of aquatic pollutants
Authors: Babich H. , Borenfreund E. 
Published: October 2006

AbstractThe volume of chemicals in everyday use that require ecotoxicity testing, the high‐costs of using whole animals for initial screenings of chemicals for their cyto‐ and genotoxicities, and the need for a ‚biological early warning signal”︁ to detect toxicants in aquatic environments have prompted the development of many microbial‐based in vitro short‐term bioassays. An area that has received relatively little study is the application of vertebrate cells, especially fish cells, for ecotoxicity testing of chemicals. From the few studies that are available it has been demonstrated that cultured, established fish cell lines can be used for (1) the in vitro cyto‐ and genotoxicity screening of known aquatic pollutants, (2) the in situ monitoring of natural waters and sediments for chemical cyto‐ and genotoxicants, and (c) elucidating structure‐activity relationships among chemicals, which can thereby serve as a biological adjunct to computer‐based mathematical predictions (QSARs) of chemical cyto‐ and genotoxicity.
Assessment for mutagenicity of 10 pharmaceutical products following ames, micronucleus, and sperm morphology testing
Authors: Stoyanov I. S. , Nicolov I. G. , Chernozemsky I. N. , Stoichev I. 
Published: October 2006

AbstractTen widely used pharmaceutical agents for which mutagenicity or carcinogenicity data are still lacking were tested in parallel with three methods: Ames' bacterial mutagenicity test (TA1535, TA1537, TA98, and TA100 Salmonella strains), micronucleus (mice BDF1), and sperm morphology abnormality (mice) tests. The groups and generic names of the tested products, all produced by Pharmachim (Bulgaria), were as follows: Psychopharmaca (Loxapinsuccinate, Medazepam hydrochloride, Nomifensinmaleate, Viloxazine hydrochloride), Vasodilatators (Nitroprussid Na, Isosorbid mononitrate, Isosorbid dinitrate), Spasmolytica (Trimetoquinol), Antirheumatica (Diclofenac Na), and the antimycotic agent Lavendotricin. In all tests, negative results were obtained. To avoid false negative results, several suggestions are made.
Effects of 2,4‐dichlorophenoxyacetic acid on Rhizobium sp. in pure culture
Authors: De Peretti A. I. Fabra , De Moro G. B. Mori , Ghittoni N. E. , De Duffard A. M. Evangelista , Duffard R. O. 
Published: October 2006

AbstractThe effects of 2,4‐Dichlorophenoxyacetic acid on the growth rate, chemical composition, 14C‐2,4‐dichlorophenoxyacetic acid and 45Ca2+ uptake by Rhizobium sp. M 4 able to nodulate Arachis hypogaea were determined. Cellular growth was diminished by the presence of 10−3 M 2,4‐dichlorophenoxyacetic acid in the medium. Alterations in cellular chemical composition, in 14C‐2,4‐dichlorophenoxyacetic acid and in 45Ca2+ uptake were found.
Biodegradation and adsorption of DBCP and the mathematical simulation of its transport in tropical soils
Authors: Liu Clark C. K. , Tamrakar Noor K. , Green Richard E. 
Published: October 2006

AbstractDibromochloropropane (DBCP) has been used to control nematodes since 1955 by pineapple growers in Hawaii, U.S.A. A major portion of the applied chemical eventually volatilizes to the atmosphere, but a residual amount adsorbed to soil particles may percolate downward with infiltrating water and become the source of groundwater contamination. Apart from volatilization, biodegradation is the only other means of loss of DBCP from soils. Although DBCP has been accepted as biologically stable, recent laboratory and field experiments indicate that it undergoes slow degradation in the presence of microorganisms. A numerical model was formulated and applied to simulate DBCP transport and transformation in soils. Relevant physicochemical and biological actions are incorporated in the model formulation. With values of other model parameters established independently, it was possible to evaluate the coefficients of DBCP biodegradation and adsorption by model calibration. The modeling results suggest the rate of biodegradation is greater in the top layer of the soil where the population of microorganisms is greater, and decreases as greater depths are reached. For two test fields on the island of Maui, the rate of degradation was found to be 0.00016/hr in the top 45 cm of soil, 0.00014/hr for a depth up to 90 cm, and 0.00006/hr for greater depths. The decrease of DBCP residual due to biodegradation was also found to depend on the adsorption of DBCP to soil particles. A high adsorption in the top layer of soil retards the movement of the pesticide and thus allow a significant biodegradation to take place.
Inhibition of H+ efflux and K+ uptake, and induction of K+ efflux in yeast by heavy metals
Authors: White C. , Gadd G. M. 
Published: October 2006

AbstractEnergy and cell membrane ATPase‐dependent H+ efflux from yeast cells was inhibited by heavy metals, which also inhibited energy‐dependent K+ uptake by the cells. Heavy metals also induced K+ efflux from metabolizing cells in two phases: reversibly at low concentrations and irreversibly at high concentrations. The concentration dependence of all of these effects varied considerably between metals.The effect of in vivo inhibition of H+ transporting ATPases on cell membrane polarization and thus on cellular transport processes, including heavy metal uptake, are discussed. It is proposed that the inhibition of H+ efflux and the appearance of irreversible K+ efflux in yeast are potentially useful indicators of heavy metal toxicity toward yeast and possibly other fungi.
Changes of glycolipids and gangliosides in 2,4‐dichlorophenoxyacetic acid treated Chinese hamster ovary cells in monolayer culture
Authors: De Duffard Ana María Evangelista , Rivarola Viviana , Duffard Ricardo 
Published: October 2006

AbstractThe effects of 2,4‐dichlorophenoxyacetic acid (2,4‐D) on the growth of Chinese hamster ovary cells were studied. 2,4‐D (10−3M) had a cell growth inhibitory effect on CHO cells in monolayer cultures. When 2,4‐D was removed after four days of treatment, a rapid resumption of cell growth rate occurred. At 10−5M 2,4‐D, only a delay of growth was observed, and glycolipid and ganglioside contents were increased in both logarithmic and stationary phases of culture, while no changes in protein, cholesterol, and phospholipids were observed.
Mutagenicity studies of dioxin and related compounds with the Salmonella arabinose resistant assay system
Authors: Soler‐Niedziela L. , Ong T. , Nath J. , Zeiger E. 
Published: October 2006

AbstractComponents of the herbicide Agent Orange—2,4‐dichlorophenoxyacetic acid (2,4‐D) and 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T), and their esters in addition to the contaminant 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD)—and related chemicals were tested for mutagenicity using the Salmonella arabinose resistant assay system. The preincubation test using strain SV50 was performed both with and without metabolic activation. No mutagenic activity was observed for any of the chemicals tested.
Studies on the genotoxicity of dipyridyl and biphenyl derivatives using Salmonella typhimurium
Authors: Lin Jen‐Kun , Kuo Ming‐Liang , Hsu Lee‐Way 
Published: October 2006

AbstractParaquat (1,1′‐dimethyl‐4,4′‐bipyridinum dichloride) is a widely used herbicide, and the high incidence of preneoplastic lesion on the skins of the workers in a Paraquat manufactory indicates the potential genotoxicity of this compound and its derivatives. Paraquat is made from 4,4′‐dipyridyl by methylation. During the course of synthesis of 4,4′‐dipyridyl, several by‐products such as 2,2′‐, 2,3′‐, 3,3′‐, and 2,4′‐dipyridyls are formed. Some investigators have claimed that the genotoxicity of Paraquat preparation might be due to the presence of these by‐products, but detailed experimental evidence is lacking. In this article, a systematic study on the mutagenicity of these compounds, we show these compounds to be moderately mutagenic in the presence of S9 mix. Both Paraquat and 4,4′‐dipyridyl are less active in these mutagenicity assays.Biphenyl derivatives are similar to dipyridyls in chemical configuration. Furthermore, two generally known carcinogens, 2‐acetylaminofluorene and benzidine, are biphenyl derivatives. Several related compounds including N‐acetoxy‐2‐acetylamino‐fluorene, 2 nitrofluorene, and the newly synthesized compounds N‐nitroso‐N,N′‐diacetyl‐benzidine, N‐nitrosophenacetin, and N‐nitroso‐2‐acetylaminofluorene were tested for their mutagenicities in the Salmonella system. The results indicate that N‐nitroso‐biphenyl derivatives are direct mutagens. This finding strongly suggests that nitrosation might play an important role in the activation of certain amines and amides in the living organisms.
Assessment of mutagenic activity of coastal sediments of Barcelona
Authors: Grifoll M. , Solanas A. M. , Parés R. , Centellas V. , Bayona J. M. , Albaigés J. 
Published: October 2006

AbstractOrganic extracts isolated from coastal sediments off Barcelona were submitted to the Salmonella/microsomal mammalian mutagenicity test (strains TA 98, 100, and 1538). The results obtained were ambiguous and a lack of dose‐response correlation was observed. However, when the extracts were resolved in fractions of increasing polarity these showed a parallel increase in mutagenicity, although the most polar were toxic. This seems to indicate that interferences among components may occur and a chemical class fractionation is needed for a better assessment of the mutagenicity of these samples.Polycyclic aromatic hydrocarbons (benzofluoranthenes, benzo[a]pyrene, and alkyl‐substituted benzo[a]anthracenes) identified in the intermediate fractions by HRGC‐MS, could account for the mutagenicity observed. However, in the polar fractions only biogenic components (e.g., linear and steroidal alcohols and ketones) and traces of toxic xenobiotics (e.g., nonylphenol derivatives) were identified. On these grounds, it is suggested that the mutagenicity of some unknown components could be enhanced by the concurrence of the cocarcinogenic lipids found.
Relative sensitivity of algae, bacteria, invertebrates, and fish to phenol: Analysis of 234 tests conducted for more than 149 species
Authors: Walker John D. 
Published: October 2006

AbstractAn analysis was conducted to estimate the relative sensitivities of algae, bacteria, fish, and invertebrates to one chemical—phenol. Results from 234 studies to estimate the toxicity (EC50 or LC50 value) of phenol to 1 rotifer, 3 algal species, 4 leech species, 9 worm species, 12 fish species, 13 water mite species, 20 bivalve species, 22 crustacean species, greater than 26 bacterial species, and 39 insect species were analyzed to estimate relative, not absolute, sensitivities within and between species and between groups of species.EC50 values from conducting ten 5‐min Microtox® tests were very similar as were EC50 values from conducting two activated sludge respiration inhibition tests. Three‐fold and thirty‐fold differences were observed for two 120‐min Motility and two Oxygen‐depletion tests, respectively. Most of the fish within‐species variability could be accounted for by differences in test temperatures. Most of the invertebrate within‐species variability could be accounted for by lab‐to‐lab or test‐to‐test variability.Differences between bacterial tests to measure five physiological endpoints (bioluminescence, respiration, growth, dehydrogenase, motility) were estimated. Differences between the EC50 values for the two tests to measure bioluminescence were significant. However, none of the mean EC50 values from tests to measure five physiological end‐points appeared to be significantly different. Mean LC50 values from conducting fish tests were compared; only the rainbow trout and fathead minnow were significantly different.A comparison of relative species sensitivity suggested that bluegills, daphnids, fathead minnows, featherbacks, giant gourami grass shrimp, guppies, P. phosphoreum in the 5‐min Microtox® test or rainbow trout were among the more sensitive species to the acute effects of phenol. A comparison of groups of species suggested that caddisfly or dragonfly larvae, crustaceans, daphnids, fish, shrimp and water fleas were among the more sensitive species groups to the acute effects of phenol.
Enteric viruses and coliphages in Latin America
Authors: Toranzos Gary A. , Gerba Charles P. , Hanssen Henry 
Published: October 2006

AbstractDrinking and other types of waters in three Latin American countries were sampled for the presence of enteroviruses, rotaviruses, and coliphages. Large volumes of water and sewage were concentrated using a positively charged filter for the detection of enteric viruses. Statistical analyses indicated no correlation between the presence or absence of fecal coliforms, total coliforms, fecal streptococci, and viruses. Total coliforms and fecal streptococci were isolated in large numbers from pristine tropical rain forest streams, but no enteric viruses were detected in any of the same samples. All streams contaminated with sewage contained enteric viruses and high levels of indicator bacteria. These results indicate that at the present time there is no reliable indicator of the presence of viruses in waters. The presence of coliphages in waters seemed associated with fecal contamination. The large numbers of fecal streptococci and coliforms (both fecal and total) present in the waters sampled may not necessarily indicate that these waters are contaminated with fecal waste.
Pathogenic indicators in lake kinneret, Israel
Authors: Hadas Ora 
Published: October 2006

AbstractThe distribution of five pathogenic indicators (Fecal coliforms, Escherichia coli, enterococci, Clostridium perfringens, and F‐male specific bacteriophages) was studied at four representative sites from Lake Kinneret. Maximum bacterial and phage numbers were detected during the winter rainy season and at the Jordan River inlet. Much lower bacterial numbers were noted in the beaches and during the summer. A good correlation was achieved between bacterial occurrence and F‐male specific phages at the Alumot beach, but poor correlation was seen in the Jordan inlet.
Molluscan shellfish and water quality problems in Atlantic Canada
Authors: Menon Amar S. 
Published: October 2006

AbstractThis paper describes the operation of the Canadian Shellfish Sanitation Program and the impact of coastal pollution on Atlantic Canada shellfish growing areas. Criteria for the classification of shellfish growing waters in Canada are based primarily on the sanitary conditions and the bacteriological water quality of the specific growing area. Wastewater discharges to the marine environment exert great economic and social impact on the local molluscan shellfish industry in Atlantic Canada. Approximately 146,000 ha of potential shellfish producing areas are closed to shellfishing because of fecal pollution. Point source and nonpoint source pollution contribute approximately equally to shellfish growing area contaminations. Effective pollution control and management of coastal zone development are needed to protect Atlantic shellfish‐growing water quality.
Anandamide mediates hyperdynamic circulation in cirrhotic rats via CB1 and VR1 receptors
Authors: Moezi L , Gaskari S A , Liu H , Baik S K , Dehpour A R , Lee S S 
Published: October 2006

Background and purpose:Hyperdynamic circulation and mesenteric hyperaemia are found in cirrhosis. To delineate the role of endocannabinoids in these changes, we examined the cardiovascular effects of anandamide, AM251 (CB1 antagonist), AM630 (CB2 antagonist) and capsazepine (VR1 antagonist), in a rat model of cirrhosis.Experimental approach:Cirrhosis was induced by bile duct ligation. Controls underwent sham operation. Four weeks later, diameters of mesenteric arteriole and venule (intravital microscopy), arterial pressure, cardiac output, systemic vascular resistance and superior mesenteric artery (SMA) flow were measured after anandamide, AM251 (with or without anandamide), AM630 and capsazepine administration. CB1, CB2 and VR1 receptor expression in SMA was assessed by western blot and RT‐PCR.Key results:Anandamide increased mesenteric vessel diameter and flow, and cardiac output in cirrhotic rats, but did not affect controls. Anandamide induced a triphasic arterial pressure response in controls, but this pattern differed markedly in cirrhotic rats. Pre‐administration of AM251 blocked the effects of anandamide. AM251 (without anandamide) increased arterial pressure and systemic vascular resistance, constricted mesenteric arterioles, decreased SMA flow and changed cardiac output in a time‐dependent fashion in cirrhotic rats. Capsazepine decreased cardiac output and mesenteric arteriolar diameter and flow, and increased systemic vascular resistance in cirrhotic rats, but lacked effect in controls. Expression of CB1 and VR1 receptor proteins were increased in cirrhotic rats. AM630 did not affect any cardiovascular parameter in either group.Conclusions and implications:These data suggest that endocannabinoids contribute to hyperdynamic circulation and mesenteric hyperaemia in cirrhosis, via CB1‐ and VR1‐mediated mechanisms.British Journal of Pharmacology (2006) 149, 898–908. doi:10.1038/sj.bjp.0706928