Spirillum Volutans Research Articles

Judicial Opinions 103-111.

In Opinion 103, the request to place the name Spirillum volutans Ehrenberg 1832 (Approved Lists 1980) on the list of rejected names is denied because a neotype may be designated. Similarly, because a neotype may be designated, in Opinion 104 the request to place the name Beijerinckia fluminensis Döbereiner and Ruschel 1958 (Approved Lists 1980) on the list of rejected names is denied. In Opinion 105, it is emphasized that the name Rhodoligotrophos Fukuda et al. 2012 does not contravene the Code. The request to orthographically correct Rhodoligotrophos Fukuda et al. 2012 to Rhodoligotrophus corrig. Fukuda et al. 2012 is denied. Opinion 106 addresses two Requests for an Opinion and results in the placement of the epithet hoagii in Corynebacterium hoagii (Morse 1912) Eberson 1918 (Approved Lists 1980) and Rhodococcus hoagii (Morse 1912) Kämpfer et al. 2014 on the list of rejected specific and subspecific epithets. Since this removes all known available earlier synonyms of Rhodococcus equi (Magnusson 1923) Goodfellow and Alderson 1977 (Approved Lists 1980), the request to conserve the epithet equi in this name is denied. In Opinion 107, Thermomicrobium fosteri Phillips and Perry 1976 (Approved Lists 1980) is placed on the list of rejected names as a nomen dubium et confusum. Opinion 108 denies the request to place Hyphomonas rosenbergii Weiner et al. 2000 on the list of rejected names because the information provided to the Judicial Commission is not sufficient to draw a conclusion on this matter. In Opinion 109, which addresses three Requests for an Opinion, the Judicial Commission denies the requests to place the names Bacillus aerius Shivaji et al. 2006, Bacillus aerophilus Shivaji et al. 2006 and Bacillus stratosphericus Shivaji et al. 2006 on the list of rejected names. Instead, it is concluded that these three names had not met the requirements for valid publication. Likewise, the Judicial Commission concludes in Opinion 110 that the name Actinobaculum massiliense corrig. Greub and Raoult 2006 had not met the requirements for valid publication. The Judicial Commission reaffirms in Opinion 111 that Methanocorpusculum parvum Zellner et al. 1988 is the nomenclatural type of Methanocorpusculum Zellner et al. 1988 and further emphasizes that the species was not in danger of losing this status. These Opinions were ratified by the voting members of the International Committee on Systematics of Prokaryotes.

River Monitoring of Mercury using a novel Molybdenum-Reducing Enzyme assay

An inhibitive assay for mercury using a molybdenum-reducing enzyme assay system from Serratia sp. Strain DRY8 is presented. Mercury showed a sigmoidal inhibition curve with a calculated IC50 using the four-parameter logistic model of 2.101 mg l-1. The limit of detection (LOD) and limit of quantitation (LOQ) for mercury were 0.021 and 0.237 mg l-1, respectively. Other heavy metals tested at the final concentrations of 5.0 mg l-1 were not inhibitory to the assay. The enzyme requires 12-molybdophosphoric acid as an electron acceptor substrate and NADH as the electron donor substrate. The enzyme in the crude extract converted the yellowish solution into a deep blue solution with a maximum peak at 865 nm and a shoulder at 710 nm. The comparative IC50 (concentration causing 50% inhibition) data for lead for different toxicity tests show that the IC50 value for mercury was lower than the synthetic activated sludge assay and within the range of the Spirillum volutans and the dehydrogenase activity assays. A water sample from the Juru Industrial estate gave positive toxicity results with mercury far exceeding the maximum permissible concentrations allowed by the Malaysian Department of Environment. The waters from tap, a forest reserve, and a recreational area gave negative toxicity for mercury in agreement with ICP-AES results which showed the presence of heavy metals at the non-detectable levels.

Proposal of Spirillum winogradskyi sp. nov., a novel microaerophilic species, an emended description of the genus Spirillum and Request for an Opinion regarding the status of the species Spirillum volutans Ehrenberg 1832

A novel obligately organotrophic, facultatively microaerophilic spirillum, designated strain D-427(T), was isolated from sulfidic sludge of a municipal wastewater-treatment plant. Cells were Gram-negative, large and highly motile due to bipolar tufts of flagella covered with mucous sheaths. Coccoid cells were sometimes formed. Strain D-427(T) grew optimally at pH 7.5-7.8 and 28 degrees C in the presence of 2 % O(2) in the gas phase. The organism showed oxidase and very low catalase activity. The isolate grew chemo-organotrophically with a limited number of organic acids as substrates. The DNA G+C content was 38.0 mol% (T(m)). Phylogenetic analysis of the 16S rRNA gene sequence placed strain D-427(T) in the genus Spirillum within the class Betaproteobacteria. The 16S rRNA gene sequence similarity between strain D-427(T) and Spirillum volutans ATCC 19554(T), the type strain of the single species of the genus, was 98.6 %. The low level of DNA-DNA hybridization and different phenotypic properties indicate that strain D-427(T) is clearly distinguishable from Spirillum volutans. No strain of S. volutans is available from any established culture collection or from the authors who described this species. Therefore, on the basis of phenotypic and genotypic data and the fact that the type and single species of the genus Spirillum cannot be included in any scientific study, since the type strain has been lost, we propose to assign strain D-427(T) as a novel species of the genus Spirillum, Spirillum winogradskyi sp. nov. (type strain D-427(T) =DSM 12756(T) =VKM B-2518(T)), and we request that the Judicial Commission place the name Spirillum volutans on the list of rejected names if a suitable type strain is not found or a neotype is not proposed within 2 years following the publication of this paper. An emended description of the genus Spirillum is also provided.

Two new species of microaerophilic sulfur spirilla, Spirillum winogradskii sp. nov. and Spirillum kriegii sp. nov.

New microaerophilic sulfur-oxidizing spirilla were isolated from hydrogen sulfide sludge of wastewater treatment plants. Strains D-427 and D-430 have spiral cells that are highly motile due to bipolar flagellum bundles covered with mucous sheaths. Under a phase-contrast microscope, these bundles are visible as single polar flagella. Spheroplasts are formed in the stationary growth phase. Both strains are obligate organotrophs able to oxidize a number of reduced sulfur compounds. The oxidation of sulfide and polysulfide leads to the formation of intracellular globules of elemental sulfur; thiosulfate oxidation results in tetrathionate accumulation in the medium. The cells are unable to utilize reduced sulfur compounds in the energy metabolism; their oxidation is caused by a chemical interaction with H2O2 and O2, synthesized in the electron transport chain. Both strains are obligate microaerophiles with an optimal oxygen concentration in the gas phase of 2 and 0.8% for strains D-427 and D-430, respectively. The strains utilize a limited number of organic acids as growth substrates, mainly tricarboxylic-acid-cycle intermediates. The DNA G+C content is 38.0 mol % (T(m)) for strain D-427 and 38.9 mol % for strain D-430. Phylogenetic analysis, based on the comparison of 16S rRNA gene sequences, revealed that the new isolates of sulfur spirilla are the most closely related to Spirillum volutans, the type species of the genus (97.4% similarity). They were assigned to the genus Spirillum within the class Beta-proteobacteria as two new species, S. winogradskii sp. nov. (D-427T = DSM 12756T) and S. kriegii sp. nov. (B-430T = BKM B-2372T). The emended description of the genus Spirillum is provided.

Toxicity tests to assess pollutants removal during wastewater treatment and the quality of receiving waters in Argentina.

In Argentina, legislation to control adverse impacts of effluent discharges and the quality of receiving waters is scant and relies mainly on the physicochemical characteristics of the effluents and receiving waters. Objectives of this study were to use standardized acute toxicity tests to assess treatment of petrochemical industry effluents and the toxicity of various treated industrial effluents in the Buenos Aires metropolitan area and their receiving waters. Tests for the first objective used Daphnia magna and Ceriodaphnia dubia; those for the second used D. magna, Spirillum volutans, and Scenedesmus spinosus. Chemical analyses demonstrated that the removal of aromatic hydrocarbon compounds (benzene, toluene, ethylbenzene, xylene, styrene, and naphthalene) from the petrochemical effluents ranged between 77 and 93%, but toxicity removal was significantly lower: untreated effluents were very toxic and treated effluents were very toxic to toxic [acute toxicity units (TUa) > 3]. Physicochemical parameters measured according to current Argentinian regulations indicated that industrial effluents (e.g., from textile and paper industries) were within established guidelines, but 25% of the samples were moderately to highly toxic (TUa > 1.33). However, for the receiving waters, toxicity tests were moderate to very toxic. The results show the need of including tests for toxicity of discharged effluents, and their effects on receiving waters of Argentina, especially for regulatory purposes.

Identification of a gene for a rubrerythrin/nigerythrin-like protein in Spirillum volutans by using amino acid sequence data from mass spectrometry and NH2-terminal sequencing.

A hydrogen peroxide-resistant mutant of the catalase-negative microaerophile, Spirillum volutans, constitutively expresses a 21.5 kDa protein that is undetectable and non-inducible in the wild-type cells. Part of the gene that encodes the protein was cloned using amino acid sequence data obtained by both mass spectrometry and NH2-terminal sequencing. The deduced 158 amino acid polypeptide shows high relatedness to rubrerythrin and nigerythrin previously described in the anaerobes Clostridium perfringens and Desulfovibrio vulgaris. The protein also shows high similarity to putative rubrerythrin proteins found in the anaerobic archeons Archaeoglobus fulgidus, Methanococcus jannaschii and Methanobacterium thermoautotrophicum. This is the first report of this type of protein in an organism that must respire with oxygen. It seems likely that the novel combination of methodologies used in this study could be applied to the rapid cloning of other genes in bacteria for which no genomic library yet exists.

A hydrogen peroxide resistant mutant of <I>Spirillum volutans</I> has NADH peroxidase activity but no increased oxygen tolerance

A hydrogen peroxide resistant mutant of <I>Spirillum volutans</I> has NADH peroxidase activity but no increased oxygen tolerance

A hydrogen peroxide resistant mutant ofSpirillum volutanshas NADH peroxidase activity but no increased oxygen tolerance

The catalase-negative microaerophile Spirillum volutans is killed rapidly by levels of H2O2greater than 10 μM. A mutant isolated by single step mutagenesis with diethyl sulfate was able to survive and grow after exposure to 40 μM H2O2and was effective in eliminating H2O2added to the medium. Nevertheless, the mutant was no more colerant to O2than the wild type. The only apparent phenotypic difference between the wild type and the mutant was that the mutant had high NADH peroxidase activity (0.072 IU.mg-1) whereas the wild type had no detectable activity (<0.0002 IU.mg-1). NADH peroxidase has not previously been reported in gram-negative bacteria or in bacteria having a strictly respiratory type of metabolism.Key words: microaerophile, Spirillum volutans, peroxidase, oxygen tolerance, hydrogen peroxide.

Improved method for colony counts of the microaerophile Spirillum volutans

Studies of adaptive responses of Spirillum volutans to various stresses such as heat shock have been hampered by an inability to obtain reliable colony counts of the organism by the spread plate method, due in part to differences among various lots of the casein hydrolysate component of the medium. Colony counts approaching direct microscopic counts (DMCs) were obtained by inoculating culture dilutions into a semisolid version of the medium and using this to overlay a thicker layer of sterile medium, and by supplementing the medium with pyruvate, which destroys hydrogen peroxide. Both the pyruvate and the overlay were necessary for optimal results. Use of the new overlay–pyruvate method for colony counts revealed that exposure of S. volutans to 40 °C for 100 min results in a greater survival at 45 °C compared with cells having no prior exposure to 40 °C.Key words: pyruvate, microaerophile, Spirillum volutans, heat shock.

Toxicity evaluation using bioassays in rural developing district 063 Hidalgo, Mexico

One of the oldest and biggest irrigation districts that use wastewater in Mexico is the Rural Developing District 063 (RDD-063). The water supplies of this district are the industrial and domestic discharges of Mexico City and its metropolitan area. RDD-063 production of grains, vegetables, and fruits as well as cattle products supplies the Mexico City market, so it is important to evaluate the chemical risks to which this population is exposed. Fourteen sampling sites were selected for collection of water, soil, and sediment samples in March, July, and October 1993. Bioassays with Daphnia magna, Spirillum volutans, and Panagrellus redivivus were used to estimate acute toxicity and genotoxicity in water samples, sediment pore water, and Milli-Q water extracts of soil. Acute toxicity effects were detected in March and October, while in July genotoxicity responses were found. The results demonstrate that RDD-063 had serious ecological damage, and its waters, soils, and sediments represent a hazard to animal and human health. Bioconcentration and persistence of toxic substances in drinking and irrigation water is a major problem that requires a long-term solution. © 1996 by John Wiley & Sons, Inc.

Toxicity of zinc in three microbial test systems

A feasibility study on the potential use of three bacterial test systems on the toxicity screening of zinc is presented. In this investigation, the toxicity screening procedures included, were the Microtox test using a luminescent halophyte bacterial strain, Photobacterium phosphoreum, a motility test employing Spirillum volutans, and a growth zone inhibition test using Bacillus cereus as the test organism. The EC50 value of zinc has been found to be 1.35 mg/L with the Microtox test under optimum test conditions (T15oct15min). However, the toxic response of zinc was significantly dependent upon the test temperature and incubation time. It decreased at higher temperatures and increased with longer incubation periods. In the case of the motility test, the minimum effective concentration (90%) value of zinc was 3.00 mg/L at optimum assay conditions (T28oct60min) while the toxicity of zinc in the growth zone inhibition procedure was found to be 2.25 mg/L at 30°C after 18 h incubation. Overall, the study showed that the Microtox test was the most sensitive screening procedure followed by the growth zone inhibition test, and the motility test was least sensitive among the three test systems. The growth zone inhibition procedure was the simplest of all the systems. © 1996 by John Wiley & Sons, Inc.

Toxicity of organomercury compounds: bioassay results as a basis for risk assessment.

A former mercury plant, where mercury salts and organomercurials for pesticide use were produced, caused soil contamination in high concentrations. Typical organomercurial products included ethylmercury, phenylmercury, methoxyethylmercury and ethoxyethylmercury compounds. Risk assessment of these sites must be carried out before any major clean-up processes can be planned. A sensitive speciation technique for the various organomercury species in environmental matrices is a prerequisite for toxicity investigations. In this connection, a high-performance liquid chromatography-atomic fluorescence spectrometry (HPLC-AFS) technique has been developed to differentiate between and determine the presence of eight organomercury compounds in environmental samples. Using this technique, methylmercury, ethylmercury and phenylmercury and some unknown organomercury species were found in soil samples collected from the sites of an old mercury products producing plant. With regard to risk assessment, it is necessary to assess the toxicity of the organomercurials. As different microbial metabolic pathways react differently to mercury and its compounds, batteries of bioassays are, therefore, useful to evaluate the toxicity of pollutants. To describe the toxicity and genotoxicity of MeHg+, MeOEtHg+, EtHg+, EtOEtHg+ and PhHg+, p-tolymercury chloride, nitromersol and Hg2+ six bioassays were used: resazurin reduction method, Spirillum volutans test, nematode toxicity assay Panagrellus redivivus, Toxi-Chromotest and SOS-Chromotest. A ranking of the toxicity of the organomercurial is shown. The SOS-Chromotest indicated genotoxicity for 5-7 organomercurials.

THE SWIMMING OF UNIPOLAR CELLS OF SPIRILLUM VOLUTANS: THEORY AND OBSERVATIONS

Bright-field high-speed cinemicrography was employed to record the swimming of six unipolar cells of Spirillum volutans. A complete set of geometrical parameters for each of these six cells, which are of typical but varying dimensions, was measured experimentally. For each cell, the mean swimming linear and angular speeds were measured for a period representing an exact number of flagellar cycles (at least four and up to 12 cycles). Two independent sets of measurements were carried out for each cell, one relating to the trailing and the other to the leading configuration of the flagellar bundle. The geometry of these cells was numerically modelled with curved isoparametric boundary elements (from the measured geometrical parameters), and an existing boundary element method (BEM) program was applied to predict the mean swimming linear and angular speeds. A direct comparison between the experimentally observed swimming speeds and those of the BEM predictions is made. For a typical cell, a direct comparison of the swimming trajectory, in each of the trailing and the leading flagellar configurations, was also included. Previous resistive force theory (RFT) as well as slender body theory (SBT) models are both restricted to somewhat non-realistic 'slender body' geometries, and they both fail to consider swimming kinematics. The present BEM model, however, is applicable to organisms with arbitrary geometry and correctly accounts for swimming kinematics; hence, it agrees better with experimental observations than do the previous models.

Toxicity of leachate from automobile tires to aquatic biota

A laboratory study was conducted to determine if automobile tires immersed in fresh water leach chemicals which are toxic to aquatic biota. Three tire types were examined - tires obtained from a floating tire breakwater; road-worn tires from the same vehicle; and new tires. Whole tires were immersed in 300 L of water (natural groundwater) and subsamples (40 L) of water were removed at 5, 10, 20 and 40 d for use in acute static lethality tests. Overlying water from both new and used tires was lethal to rainbow trout ( Oncorhynchus mykiss) but leachate from used tires was more toxic (96-h LC50s - 11.8 to 19.3 %v/v) than leachate from new tires (96-h LC50s - 52.1 to 80.4 %v/v). In addition, leachate remained relatively toxic to rainbow trout over time (8 d for new and 32 d for used) after tires were removed from the aquaria indicating that the chemicals responsible for toxicity degrade slowly and are non-volatile. No toxicity to cladocerans ( Daphnia magna; 48-h exposure) or fathead minnows ( Pimephales promelas; 96-h exposure to leachate from 20 and 40 d only) was observed with these same leachates. Tires from a floating tire breakwater which had been installed for several (10) years did not release chemicals which were toxic to any species tested. In separate experiments, concentrated (10X) leachate from tires immersed for 25 d in water inhibited bioluminescence in the marine bacterium, Photobacterium phosphoreum, (Microtox™ test), the enzyme, β-galactosidase, in mutant Escherichia coli (ToxiChromo™ Test) and the enzyme, NADH-coenzyme Q reductase, in the inner membrane of mitochondria (beef heart submitochrondria particle test). Several other screening tests (e.g., nematode lethality/mutagenicity test; bacterium ( Spirillum volutans) motility inhibition test and the SOS-Chromotest with and without S-9 activation) were not sensitive to tire leachates. Further studies to identify the toxic compounds and to determne the extent of toxicity under field conditions of dilution are necessary.

Phylogenetic Position of Taylorella equigenitalis Determined by Analysis of Amplified 16S Ribosomal DNA Sequences

The 16S ribosomal DNA sequence of Taylorella equigenitalis (formerly Haemophilus equigenitalis), the causative organism of contagious equine metritis, was determined. A phylogenetic analysis of this sequence revealed a phylogenetic position of T. equigenitalis in the beta subclass of the class Proteobacteria apart from the position of Haemophilus influenzae, which belongs to the gamma subclass of Proteobacteria. A close phylogenetic relationship among T. equigenitalis, Alcaligenes xylosoxidans, and Bordetella bronchiseptica was detected; Spirillum volutans and Chromobacterium fluviatile (Iodobacter fluviatile) were in the same group but slightly removed. This relationship is surprising in view of the considerable differences in the G + C contents of the genomes of these bacteria.

Chromobacterium, Eikenella, Kingella, Neisseria, Simonsiella, and Vitreoscilla Species Comprise a Major Branch of the Beta Group Proteobacteria by 16S Ribosomal Ribonucleic Acid Sequence Comparison: Transfer of Eikenella and Simonsiella to the Family Neisseriaceae (emend.)

The 16S ribosomal ribonucleic acid sequences of the type strain and three other strains of Eikenella corrodens, the type strains of Alcaligenes faecalis, Alcaligenes xylosoxydans subsp. denitrificans, Chromobacterium fluviatile, Chromobacterium violaceum, Kingella denitrificans, Kingella kingae, and Pseudomonas cepacia, and a strain of Vitreoscilla stercoraria were determined by direct sequencing of bacterial ribosomal ribonucleic acid by a modified Sanger method. These sequences were compared with previously published sequences of Neisseria gonorrhoeae and Pseudomonas testosteroni and unpublished sequences of Nitrosolobus sp., Nitrosomonas europaea, Rhodocyclus gelatinosus, Rhodocyclus purpura, Simonsiella muelleri, and Spirillum volutans. All of the bacteria sequenced in this study were members of the beta group of the class Proteobacteria, formerly called “purple bacteria and their relatives.” A phylogenetic tree was constructed based upon the sequence homologies. One of the findings of this study is that Eikenella corrodens is related, as indicated by percentage of sequence homology, to the following organisms: Kingella denitrificans (97.7%), Simonsiella muelleri (95.7%), Kingella kingae (96.2%), Neisseria gonorrhoeae (95.1%), Vitreoscilla stercoraria (94.4%), Chromobacterium violaceum (91.7%), and Chromobacterium fluviatile (89.8%). These bacteria constitute a newly recognized branch of the beta group Proteobacteria. The remaining species, including Pseudomonas cepacia, Alcaligenes faecalis, and Alcaligenes xylosoxydans subsp. denitrificans, are members of the major cluster of the beta group Proteobacteria. On the basis of our data we propose that the genera Eikenella and Simonsiella be placed in the family Neisseriaceae.

A model for swimming unipolar spirilla

A mathematical model employing slender body theory is constructed for a unipolar Spirillum volutans cell with the model cell allowed to move unconstrainedly in the fluid. The results are compared with observation and previous studies and the effects of varying cell dimensions are investigated.

Assessment of toxicant activity in sediments by the ECHA biocide monitor

The ECHA Biocide Monitor, a dipstick procedure originally designed to test the effectiveness of in situ biocides, was evaluated as a possible environmental toxicity assessment procedure. The dipstick procedure was applied to 94 sediment extracts which were also tested by three well documented toxicant screening procedures; Microtox, Daphnia magna and Spirillum volutans. In these samples the Daphnia magna test proved to be the most sensitive indication of toxicant activity (63 of 94) with the ECHA Biocide Monitor easily being the second most sensitive procedure with 27 of 94 sediments indicating the presence of toxic substances. Results of the investigation are detailed.

The ultrastructure and ATPase nature of polar membrane in Campylobacter jejuni.

Polar membrane in Campylobacter jejuni has been visualized on membrane vesicles. It was composed of doughnut-shaped particles 5-6 nm in diameter, with stalks, arranged in a hexagonal array. This structure was stabilized on the membrane by a high ionic strength buffer in the presence of 2-mercaptoethanol. Histochemical staining indicated localized ATPase activity at the poles of the cells. An ATPase with distinctive properties has been isolated and purified from this organism; it gives a specific activity of approximately 0.3 units/mg of protein. Electron microscopy showed doughnut-shaped particles 5-6 nm in diameter. Nondissociating and sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified enzyme revealed, respectively, a single band with ATPase activity and a molecular weight of ca. 75,000 Da. The enzyme was cold labile and activity was abolished by trypsin. Dicyclohexylcarbodiimide inhibited the membrane-bound form of the enzyme, but did not inhibit the soluble form. Oligomycin had no inhibitory activity on either form of the enzyme. The enzyme specifically hydrolysed ATP, but other nucleotide substrates were not degraded. The enzyme was activated by Mg2+ and inhibited by Ca2+, whereas other ions had no effect on activity. Antibodies prepared to this enzyme bound to the polar regions of whole cells as shown by protein A - colloidal gold immunoelectron microscopy. The antibodies to this ATPase cross reacted (shown by Western blotting) with four proteins from a whole-cell extract of this organism, two proteins in Aquaspirillum serpens MW5, and three proteins from Escherichia coli K12. They did not cross-react with any proteins from Spirillum volutans, Methanococcus voltae, Vibrio cholerae, or rat liver mitochondria. Antibodies raised against the F1-ATPase of E. coli K12 cross reacted with six proteins in a whole-cell extract of this organism, and one protein species in each of the whole-cell extracts of V. cholera, A. serpens MW5, S. volutans, and rat liver mitochondria. These antibodies did not recognize any whole cell proteins from either C. jejuni or M. voltae. These results along with the ATPase activity localized by histochemical staining suggest that polar membrane is an assembly of ATPase molecules at the poles of the cell and that the ATPase isolated from C. jejuni is serologically and structurally unusual.

Toxicity assessment of industrial effluents from S. Paulo state, Brazil, using short‐term microbial assays

AbstractMicroorganisms have demonstrated several attributes that make them attractive for use in quick screening of effluents and chemicals for toxicity. The aim of this study was to evaluate the acute toxicity and mutagenicity of industrial effluents from São Paulo State using short‐term microbial bioassays. Samples of industrial effluents and receiving waters were analyzed for acute toxicity by the Microtox system, a motility test using Spirillum volutans, growth inhibition of Pseudomonas fluorescens, and dehydrogenase assay; for mutagenicity, these samples were analyzed by Salmonella typhimurium (Ames test), Escherichia coli WP2, and Saccharomyces cerevisiae reversion mutation assays. Among the acute toxicity assays carried out in this study, the Microtox and S. volutans tests showed good sensitivity and general good agreement with the Daphnia similis assay, which demonstrates that these tests are potentially useful as toxicity indicators for the industrial effluents and receiving waters considered. In relation to mutagenicity assays, good results were obtained with the three methods tested. The detection of mutagens in the industrial effluents considered indicates that some constituents of these waste waters discharged in receiving waters can cause adverse biological effects and could be deleterious from a public health standpoint. The data of this research emphasize the importance of acute toxicity and mutagenicity assays as supplementary approaches for a rapid and efficient action in water pollution control, and for evaluation of potential toxic chemical effects.