bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein production during heat stress and exposure to toxicants in alcaligenes eutrophus JMP228
Authors: Amy Penny S. , Hiatt Hermi D. , Keith Dupre R. 
Published: October 2006

AbstractIn an effort to determine whether heat‐shock proteins might serve as useful indicators of environmental stress, the aquatic bacterium, Alcaligenes eutrophus JMP228, was exposed to two chemical stressors: a toxic heavy metal ion, cadmium, and a nonbiodegradable organic herbicide, 2,4,5‐trichlorophenoxyacetic acid (2,4,5‐T). Protein synthesis was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis, comparing the protein patterns of chemically stressed cells to those exhibited by nontreated and heat‐shocked cells. Heat‐shock proteins were produced in response to both chemical stressors and heat. Proteins induced in response to all three experimental stresses include molecules with approximate molecular weights of 58–60 and 106 kDa. Still other stress proteins were only expressed following chemical stress. A 106 kDa protein was only produced following cadmium treatment, whereas proteins of 37, 39, 46, 49, and 77 kDa were only produced in response to 2,4,5‐T. The synthesis of some of the unique stress proteins varied in a dose‐dependent fashion with the concentration of the individual stressors. The presence of these proteins may be useful indicators of the “health” of an environment. © 1993 John Wiley & Sons, Inc.
Pseudomonas aeruginosa and other microbial indicators of pollution in fresh and marine waters of rio de janeiro, Brazil
Authors: Guimarães Vanessa F. , Araújo Marlise A. V. , Mendonçla‐hagler Leda C. S. , Hagler Allen N. 
Published: October 2006

AbstractCounts of Pseudomonas aeruginosa had a high positive correlation with counts of coliforms, fecal streptococci, presumptive pathogenic yeasts, and heterotrophic bacteria in surface waters of Rio de Janeiro. Pseudomonas aeruginosa counts were notably higher in fresh than in marine waters, and it was isolated from about 50% of marine and 100% of nonchlorinated freshwater samples that passed the fecal coliform based Brazilian bathing standards. The most probable number method for enumeration of P. aeruginosa contained this microbe in 90% of the positive tubes from freshwater samples, but it had reduced selectivity in marine waters with 37.5% false negative and 35% false positive results. Microbial indicators of fecal pollution were not effective for noting the presence of P. aeruginosa in freshwaters. © 1993 John Wiley & Sons Inc.
An amperometric algal biosensor for herbicide detection employing a carbon cathode oxygen electrode
Authors: Pandard Pascal , Rawson David M. 
Published: October 2006

AbstractA method is described for continuous monitoring of the photosynthetic oxygen evolution of the microalga Chlorella vulgaris, which was immobilized between alumina filters on the surface of a teflon‐covered carbon electrode. Sensitivity of the algal biosensor to herbicides was tested using an electrochemical flow cell with illumination provided by light‐emitting diodes. This configuration also allows the biosensor to be used in real‐time environmental monitoring. The herbicides atrazine, isoproturon, and propanil were detected within 30 min at concentrations below 100 μ dm−3, while the herbicide bromoxynil was only detected after several hours at mg dm−3 concentrations. Good sensor stability was obtained in the absence of pollutants, with more than 24 h of continuous monitoring being achieved. © 1993 John Wiley & Sons. Inc.
Using the metabolic capacity of rhodobacter sphaeroides to assess heavy metal toxicity
Authors: Balsalobre C. , Calonge J. , Jiménez E. , Lafuente R. , Mouriño M. , Muñoz M. T. , Riquelme M. , Mas‐castellà J. 
Published: October 2006

AbstractHeavy metals can produce differential toxic effects on bacterial growth depending on the kind of metabolism the cells are using in relation to oxygen. Rhodobacter sphaeroides is a purple, nonsulfur, photosynthetic, gram‐negative bacterium that grows preferentially in anaerobic conditions acting as a photoheterotroph, but it can also behave as a photoautotroph. In aerobic conditions, this microorganism has a chemoheterotrophic metabolism. Aerobic and anaerobic metabolism may differ in their susceptibility to heavy metal toxicity. The metabolic duality of R. sphaeroides allowed us to assay this issue.After incubation of R. sphaeroides, several indicators of bacterial growth such as optical density, dissolved oxygen concentration, protein content, and pigment content were determined. The parameter values obtained showed that the inhibitory effect exerted by zinc and cadmium on R. sphaeroides was stronger in aerobic conditions than in anaerobic ones. Microbial growth was considerably reduced when heavy metal concentration was higher than 1 mg L−1. Besides, R. sphaeroides was quite tolerant to copper. Cultures to which copper was added from 0.01 to 10 mg L−1 showed a relatively constant growth, both in aerobic and anaerobic conditions.Thus, we have shown that assessment of heavy metal toxicity using bacterial tests must take into account that bacteria may react in a different way when grown in anaerobic environments.
Aflatoxin‐producing fungi associated with Nigerian maize
Authors: Aja‐Nwachukwu Jane , Emejuaiwe S. O. 
Published: October 2006

AbstractMaize samples were obtained from different locations—namely Aba, Abakaliki, Afikpo, Okigwe, and Owerri—all in southeast Nigeria. Twelve mold species of the genera Aspergillus, Penicillium, Cladosporium, Alternaria, Fusarium, and Acremonium (Cephalosporium) were isolated. The presence of aflatoxin B1 was 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 the Aspergillus flavus group 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 & Sons, Inc..
Studies on Bacillus thuringiensis H‐14 strains isolated in Egypt. VI. Correlation between specific plasmids and δ‐endotoxin production
Authors: Abdel‐Hameed A. , Carlberg G. , Lindström K. , El‐Tayeb O. M. 
Published: October 2006

AbstractThe crystal‐producing (cry+) strains M1 and S128 of Bacillus thuringiensis H‐14, and several noncrystal‐producing (cry−) mutants derived from them, were analyzed for the presence of plasmid DMA in attempts to correlate δ‐endotoxin production with the presence of a specific plasmid(s). Plasmid analysis of both parent strains revealed the presence of several plasmids in the size range of 3.2–130 megadalton (Mdal). The two strains were found to have identical plasmid profiles, except that strain M1 contained an additional plasmid of 68 Mdal. All the cry− mutants derived from the cry+ parental strains had lost at least a 75 Mdal plasmid. On the other hand, plasmid analysis of cry+ derivatives cured of one or more plasmids revealed that they all harbored the 75 Mdal plasmid. This correlation was further confirmed by a plasmid transfer experiment in which strain M1 transmitted the crystal‐producing phenotype to a noncrystal‐producing B. thuringiensis recipient. Agarose gel electrophoresis showed that the 75 Mdal plasmid was present in all the isolated cry+ transcipients and absent in all the isolated cry− transcipients. These results demonstrate that the structural genes for the δ‐endotoxin in the isolated strains of B. thuringiensis H‐14 are borne on the 75 Mdal plasmid. © 1994 by John Wiley & Sons, Inc..
Fertilizer applications, nitrate loading patterns, water resources quality and their ecotoxicological implications in Awka area of Nigeria
Authors: Ezeonu F. C. , Egboka B. C. E. , Aze S. S. 
Published: October 2006

AbstractNitrogen fertilizer applications at the mean rate of 500 kg ha−1 nitrogen–phosphorus–potassium, 280 kg ha−1 urea, and 200 kg ha−1 calcium ammonium nitrate reported for the year 1990 in the Awka area of Nigeria exceeded the recommended doses for the region. An inestimable amount of these are unabsorbed by plants and are leached as soluble nitrates into surface and groundwater environments. © 1994 by John Wiley & Sons, Inc..
Rapid toxicity assessment using esterase biomarkers in Brachionus calyciflorus (rotifera)
Authors: Burbank Susan E. , Snell Terry W. 
Published: October 2006

AbstractWe have developed biomarkers of sublethal toxicity in the freshwater rotifer Brachionus calyciflorus based 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, Inc..
Physiological stress in fish during toxicological procedures: A potentially confounding factor
Authors: Pottinger T. G. , Calder G. M. 
Published: October 2006

AbstractAn increasing body of evidence suggests that stress may modulate the response of an animal to toxicological challenge. The degree of stress inherent in the procedures comprising a fish LC50 study (OECD guidelines for the testing of chemicals, “Fish, Acute Toxicity Test” No. 203, adopted May 12, 1981) was assessed by measuring plasma cortisol levels (rainbow trout) and whole‐body levels of immunoreactive corticosteroids (zebra fish). Aspects of the 96 h LC50 protocol which were found to evoke corticosteroidogenic activity in the test fish included transfer from holding tanks to test tanks, tank transfer during semistatic procedures, and disturbance associated with water quality measurement. There was evidence for acclimation of the fish to repetitive stimuli such as tank transfer, but, overall, the data suggest that the 96 h test protocols evoke a state of chronic stress in the test population. The removal of fish from test vessels during longer term studies was also found to evoke a stress response in fish remaining within the vessel, suggesting that these conditions may expose test fish to a regime of intermittent periods of acute stress. The possibility that physiological stress may interfere with the accurate estimation of toxicological end points was examined. In three independent LC50 tests the toxicity of the arylmethane dye, malachite green, to rainbow trout was found to be markedly and consistently reduced when the degree of disturbance and handling during the test period was minimized. © by John Wiley & Sons, Inc.
Tissue lipid levels of the clam, Villorita cyprenoides var. cochinensis, following exposure to endosulfan, malathion, and methyl parathion
Authors: Sujatha C. H. , Nair S. M. , Chacko J. 
Published: October 2006

AbstractSublethal stress of toxicants on organisms is generally measured through metabolic changes. The effects of three pesticides (endosulfan, malathion, and methyl parathion) on tissue lipid levels in the estuarine bivalve, Villorita cyprenoids var. cochinensis, have been measured. The reduction in lipid content was expressed as a function of the pesticide concentrations and the duration of the exposure periods (24, 48, 72, and 96 h). The results point to the existence of a direct relationship between the applied stress and the fall in the lipid content. The order of toxicity was endosulfan > malathion > methyl parathion. The depletion in lipid content observed may reflect an adaptive response of the organism to pesticide stress. Thus lipids in bivalves have been shown to be an important reserve material that may be utilized under stressed conditions as an energy source. © by John Wiley & Sons, Inc.
Inhibition of respiration of activated sludge: Variability and reproducibility of results
Authors: King E. F. , Painter H. A. 
Published: October 2006

AbstractAssessment of the toxicity of chemicals to the respiration of activated sludge microorganisms is a relatively simple and reproducible method when applied to a standard population of bacteria. However, activated sludge is, by nature, a variable commodity, and varying results are often reported. Within‐plant variations can occur from day to day as a result of shifts in the bacterial population, probably caused by changes in the strength of components of the sewage feed. Between‐plant variations can be considerably greater. Factors such as differing operating conditions and presence of industrial waste waters in the sewage can result in differing species composition of the sludge, which, in turn, may account for differing biooxidation rates of components of the waste water and thus different respiration rates. Sludge from different sources, and/or grown under different conditions, may also vary in response to inhibitors, because of varying degrees of reaction of some inhibitors with non‐living sludge components. Therefore, in practice, it has been usual to consider EC50 values from the inhibition of respiration of activated sludge test in terms of order of magnitude. Variations in EC50 results of the ‘ISO’ inhibition of respiration test have been quantified for a number of chemicals, both within and between batches of sludge, and with sludges from different sources. The coefficient of variation of EC50 results within batches of sludge was found to be approximately 9%. Between batch and between source variations were 28–76% depending on the test chemical.
Rapid test for toxicity in wastewater systems
Authors: Dutton R. J. , Bitton G. , Koopman B. 
Published: October 2006

AbstractA test employing sewage bacteria was developed for rapid screening of chemical toxicity in wastewater systems. The procedure entails incubation of sewage samples with 2–(p–iodophenol)–3–(p–nitrophenyl)–5–phenyl tetrazolium chloride (INT) followed by concentration of bacteria on membrane filters, dissolution of the filters with concomittant extraction of INT‐formazan in dimethylsulfoxide, and spectrophotometric determination of the INT‐formazan.Preliminary results indicate that the test is sensitive to both heavy metals and toxic organics. Chemical concentrations inhibiting 50% of the response in controls (IC50's) for Ni+ +, Zn+ +, Cu+ +, Hg+ +, phenol, 3,4‐dichlorophenol, sodium dodecyl sulfate, tetrachloroethylene and formaldehyde were 4.8, 3.9, 0.59, 0.07, 1531, 74, 156, and 11.6 mg/l, respectively. IC50 values obtained with sewage from different collection systems or with sewage from the same system sampled on different days were in good agreement.
Methods for assessment of heavy metal toxicity towards fungi and yeasts
Authors: Gadd G. M. , Mowll J. L. , White C. , Newby P. J. 
Published: October 2006

AbstractThe analysis of K+ release, respiration rates and tests relying on diffusion processes in agar medium have applications for the study and assessment of heavy metal toxicity towards fungi and yeasts. Such techniques have been seldom exploited for this purpose but can provide information not only on toxicity but also on morphological and physiological responses towards heavy metals.
Use of the ATP bioassay to assess toxic effects in marsh treatment systems
Authors: Seyfried Patricia L. , Desjardins Robert M. 
Published: October 2006

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.
Microbial toxicity and degradation test methodology: An industrial perspective
Authors: Gledhill William E. 
Published: October 2006

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.
Toxicity of lead on microorganisms: Interaction with protein content of culture medium
Authors: Oliveira J. Santos , Rodrigues A. , Mendes B. , Dias M. 
Published: October 2006

AbstractLead is a significant environmental pollutant in Portugal, mainly as a consequence of its use as an antidetonant in gasoline. Due to the vast annual gas consumption, evidence of lead emission has been found in the air, soil, plants, and water. Concentrations of lead in Lisbon waste waters average 0.15 mg/L, with occasional levels reaching 1.5 mg/L. The biodegradability of these waste waters is affected by lead. To understand the interaction between lead toxicity and protein concentrations, a study was initiated using selected strains of Proteus mirabilis and Klebsiella pneumoniae and synthetic effluents. The toxicity of lead to bacteria was noted by an increase in the cell's metabolic activity, and a greater induction of ATP and RNA contents. However, bacterial replication was evidently uninhibited by the lead content in the test medium. While high peptone content in the growth medium caused an increase in the cell's biosynthesis, increased lead concentrations in the growth medium resulted in a substantial loss of metabolic product. This complex interaction was apparently responsible for lead's toxicity to bacteria.
Identification of Plasmid Containing Bacteria in an Activated Sludge Reactor
Authors: Trevors Jack T. 
Published: October 2006

AbstractSamples taken from an activated sludge reactor used for the biodegradation of metal cutting fluids were studied for the presence of plasmid‐containing bacteria. Twenty different bacterial isolates contained one or more plasmids. After numerous transfers of the isolates through LB broth, 55% of the plasmids were spontaneously lost as evidenced by agarose gel electrophoresis. Eighty percent of the isolates were resistant to one or more antibiotics, 65% resistant to two or more antibiotics, 40% resistant to three or more, 20% resistant to four or more and 5% resistant to five antibiotics. The isolates were also tested for their sensitivity to several common metals. This study has demonstrated that activated sludge is a natural reservoir for plasmid‐containing bacteria involved in biodegradation of wastes.
Application of enzyme assays for toxicological water testing
Authors: Obst U. , Holzapfel‐Pschorn A. , Wiegand‐Rosinus M. 
Published: October 2006

AbstractTwo different criteria for biochemical toxicity testing are proposed: the effect of hazardous substances on the metabolic activity of the natural microflora and the determination of such substances by a standardized enzyme testing system. To measure effects on the microbial metabolic activity, there are various simple in vivo enzyme assays using chromogenic or fluorogenic substrates. To detect unknown substances with harmful effects, there exist some in vitro enzyme tests with commercial preparations of defined purity and sensitivity. The performance, sensitivity, and some data of the practical use of such tests are presented. The applicability of the two testing protocols is discussed.
The Bacillus subtilis/microsome rec‐assay for the detection of DNA‐damaging substances in waters of a night soil treatment plant
Authors: Matsui Saburo 
Published: October 2006

AbstractA Bacillus subtilis/microsome Rec‐assay was improved by the introduction of a period for the test sample to interact with the bacteria before cultivation in a Monod tube. This method is called the “liquid B. subtilis/microsome Rec‐assay method.” Evaluation of the Rec‐assay is presented in terms of R50, S‐probit, and RS, which were analyzed with computer programs developed on Probit theory and Target theory. Results could be classified into four categories: strong DNA damaging, DNA damaging, not DNA damaging, and reverse. Application of the Rec‐assay to water samples from a night soil treatment plant showed that raw night soils contained a considerable amount of DNA‐damaging substances. The amount of DNA‐damaging substances in test samples was measured in terms of a new indicator, “Rec‐volume.” After the biological treatment of nitrification and denitrification process, and the tertiary treatment of chemical coagulation and floatation for phosphorus removal, DNA‐damaging substances were effectively reduced in the treated water. Following the tertiary treatment, ozonation was practiced for disinfection and color removal in this plant. Ozonation also showed effective reduction of DNA‐damaging substances in the treated waters. In order to concentrate DNA‐damaging substances in test samples, the adsorption method of XAD‐2 and XAD‐8 resins followed by ether and methanol extraction was employed.
Influence of some experimental factors on metal toxicity to Selenastrum capricornutum
Authors: Vasseur P. , Pandard P. , Burnel D. 
Published: October 2006

AbstractToxic effects of Cd++, Cu++, and Zn++ on Selenastrum capricornutum were evaluated in various experimental conditions in order to determine the influence of the composition of the test medium and of the concentration of the algal biomass on the toxicity of metals to algae. Four media recommended in different standard methods (International Standards Organisation, U.S. Environmental Protection Agency, Organisation for Economic Cooperation and Development, AFNOR) were compared. Results of algal bioassays showed that the sensitivity of algae during the exponential growth phase was not influenced by the concentration of macronutrients in the medium.On the contrary, the numeration of the algal suspensions tested appeared determinant as the toxicity decreased when the quantity of algal inoculum was increased: with inocula of nearly 3 × 104, 2.5 × 105, 6 × 105, and 3 × 106 cells/mL at t = 0, the corresponding EC50 were 46, 80, 110, and up to 300 μg/L for cadmium, 10, 65, 105, and 280 μg/L for copper, and 90, 163, 225, and 365 μg/L for zinc. Modifications in the speciation forms of the metal induced by a rapid increase of the pH could be responsible for part of this decreased toxicity.