bluuebunny/crossref_metadata_2025_split huggingface dataset:
A direct INT‐dehydrogenase assay (DIDHA) for assessing chemical toxicity
Authors: Bitton G. , Khafif T. , Chataigner N. , Bastide J. , Coste C. M. 
Published: October 2006

AbstractA direct INT‐dehydrogenase assay (DIDHA) was developed to measure chemical toxicity as well as toxicant interactions. This test consists of measuring quickly and directly the dehydrogenase activity (i.e., INT reduction) with the aid of a double beam spectrophotometer, thus avoiding formazan extraction and centrifugation steps. The assay was used to determine the toxicity of heavy metals, phenol, α‐naphtol, and herbicides (Barban, propanil, swep, BIPC, and CIPC). It was also useful in demonstrating the protective effect of clays and humic acids with regard to herbicide toxicity as well as antagonistic and synergistic interactions among toxicants.
Comparison of respiration and luminescent tests in bacterial toxicity assessment
Authors: Reteuna C. , Vasseur P. , Cabridenc R. , Lepailleur H. 
Published: October 2006

AbstractThe toxicity assessment of chemicals on complex microbial communities are generally preferred to toxic tests conducted with pure cultures of bacteria. The purpose of this study is to compare the “Respiration” test studying metabolic criteria of mix bacterial populations and the “Microtox” test using lyophilized cultures of luminescent bacteria. The inhibition of oxygen consumption was compared with the inhibition of the bioluminescence of Photobacterium phosphoreum.In the first part of this study, the methodology of the “Respiration” test and the “Microtox” test was improved to optimize their performance in toxicity assessment.In the second part, toxicity of an organic chemical, the 3,5‐Dichlorophenol, and an inorganic chemical, copper sulfate, was evaluated with the two tests. Results were compared and characteristics of the testing methods are discussed according to their sensitivity, reproducibility, representativity and ease of execution.The repeatability study for the “Respiration” test and the “Microtox” test gives variation coefficients less than 15% and 10% respectively. The variation coefficients concerning the reproducibility study are found to be 15% or 18% for the “Respiration” test, 5% or 28% for the “Microtox” test, depending on the tested toxicant. These two toxicity tests are easy to perform. But the “Microtox” test offers the advantage of being more sensitive and much faster. On the other hand, the “Respiration” test which was conducted on a microbial community is probably more representative of microflora in rivers.
Effect of suspended solids concentration and filament type on the toxicity of chlorine and hydrogen peroxide to bulking activated sludge
Authors: Chang‐Womkim  , Koopman Ben , Bitton Gabriel 
Published: October 2006

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 and Thiothrix spp., 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 IC50 to 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 in S. natans and type 021N/Thiothrix dominated sludges, but was toxicant specific in type 1701 dominated sludge. Overall, S. natans and 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 technique.
ATP‐TOX system—a new, rapid, sensitive bacterial toxicity screening system based on the determination of ATP
Authors: Xu Hao , Wuhan  , Hubei  , Dutka B. J. 
Published: October 2006

AbstractA new toxicity screening test, based on the inhibition of bacterial growth and luciferase activity by toxicants was developed. In the ATP‐TOX System, chemical toxicity was found to be time‐dependent and increased with increasing exposure time up to 5 hours. Three organisms were evaluated in this study: E. coli K‐12 PQ37, Pseudomonas fluorescens and Salmonella typhimurium. E. coli K‐12 PQ37 was found to be the most sensitive organism. It was also shown that P. fluorescens was more sensitive to toxicants when grown in minimal medium than in nutrient broth, suggesting that nutrients may have a protective effect on the bacterium. In comparative studies using selected toxic chemicals the ATP‐TOX System was found to be more sensitive than the Spirillum volutans test and comparable to the Microtox test. Toxicant activity in sediment samples was found to be time dependent and increased with increasing exposure time in both ATP‐TOX (E. coli) System and Microtox. The ATP‐TOX System is complementary to the Microtox test as it also provides indications of low grade toxicant activity which is only manifested in actively growing cells over several life cycles. Thus, the ATP‐TOX System appears to be an ideal screening test for sediment toxicity. The data indicate that the ATP‐TOX System is sensitive, rapid, reproducible, economical and has great potential in applied studies.
The effects and removal of chromium in chlamydomonas sp.
Authors: Ayoub George M. , Sayigh Bassim A. 
Published: October 2006

AbstractThe effect of chromium addition on the green alga Chlamydomonas sp. was investigated. Experiments were conducted by culturing pure stock cultures of the algae in a synthetically prepared culture medium simulating wastewater. Doses of chromium with different concentrations were added in shock and continuous forms. The effect of these doses on the growth of the algae was evaluated by carrying out algal cell counts. Possible removal of chromium by algal accumulation of the chromium was also evaluated by measuring residual chromium concentrations in the effluent. The results indicated that Chlamydomanas sp. could tolerate shock chromium doses of up to 0.2 mg. ℓ−1 and continous doses of up to 0.25 mg. ℓ−1 and can adapt to the presence of chromium in the medium. However, possible morphological changes could be induced in the cell. Furthermore, Chlamydomonas sp. was found to remove about 20% of the chromium found in the reactor.
Photobacterium phosphoreum toxicity bioassay. II. Toxicity data compilation
Authors: Kaiser Klaus L. E. , Ribo Juan M. 
Published: October 2006

AbstractThis review of Photobacterium phosphoreum toxicity bioassay, commonly known as the Microtox tests, consists of two parts. This second part (Toxicity Data Compilation) is a listing of all published and certain unpublished Microtox toxicity data for single organic compounds, including some salts and organometallic compounds. This listing consists of three tables: the first provides the reference source, toxicity value(s), chemical formula, name, the Chemical Abstracts Service (CAS) and Registry of Toxic Effects of Chemical Substances (RTECS) accession numbers, and molecular weight of each compound. At present, this table contains approximately 500 entries, which are ordered by the compounds' molecular formula. Two additional tables, ordered accordingly, are intended to provide quick access through cross‐references with the CAS and RTECS numbers, respectively.
Enzyme biosynthesis versus enzyme activity as a basis for microbial toxicity testing
Authors: Dutton R. J. , Bitton G. , Koopman B. 
Published: October 2006

AbstractA toxicity assay based on inhibition of β‐galactosidase biosynthesis was compared to a similar assay based on inhibition of β‐galactosidase activity. In both tests, Escherichia coli grown in a minimal medium was exposed to isopropyl‐β‐thiogalactoside to induce β‐galactosidase biosynthesis. The induction step preceded contact of cells with the toxicant in the enzyme activity assay, whereas in the enzyme biosynthesis test, the inducer was added following contact of cells with the toxicant. Relative sensitivity was judged on the basis of responses to the heavy metals Hg2+, Cu2+, and Cd2+, and the organics 3,4‐dichlorophenol, formaldehyde, Hydrothol, phenol, sodium dodecyl sulphate, and toluene. Comparison of these results to the IC50s achieved with other microbial systems, Daphnia bioassay, and fish bioassay indicates that the enzyme activity test was moderately sensitive to heavy metals but was insensitive to organic toxicants. The test based on inhibition of enzyme biosynthesis was sensitive to both heavy metals and toxic organics.
RK mutatest variations for rapid independent determination of toxicity and mutagenicity
Authors: Hayes Sidney 
Published: October 2006

AbstractThe RK mutatest is a recently developed, forward, short‐term, bacterial genetic test system for quantitation of mutagenic activity and toxicity. Rapid quantitative, semi‐quantitative, and qualitative variations of the standard RK mutatest protocol were developed and tested using reference genotoxic agents. Several of the reported mutatest modifications considerably reduced assay time, and would be useful for a quick first‐stage evaluation of the biological damaging effect of environmental substances.
Toxicity assessment of the antiparasitic ivermectin
Authors: Rodrigues M. A. La R. , Mattei Rita 
Published: October 2006

AbstractThe citotoxicity of ivermectin, a streptomycete‐derived macrocyclic lactone active against a wide variety of nematode and arthropod parasites, was evaluated in pig kidney cells IB‐RS‐2. The cells were cultured in the presence of different levels of ivermectin for 72 h. The cell count decreased as ivermectin concentration in the medium was increased from 0 to 20 †g/mL, and this decrease was time and dose dependent; at 40 †g/mL cell death occurred within 24 h. Ivermectin (20 †g/mL) decreased protein synthesis and glucose utilization. These effects became progressively less between 48 and 72 h when compared to untreated cells.
Fecal coliforms as indicators in tropical waters: A review
Authors: Hazen Terry C. 
Published: October 2006

AbstractNowhere is the importance of accurate determination of recent human fecal contamination greater than in the tropics. The diversity of waterborne diseases and their severity is greatest in tropical environments. Since most of the countries in tropical climates are underdeveloped, with large populations that are undernourished, ill‐housed, with poor medical services, waterborne diseases may have a much greater effect on public health in the tropics than in temperate areas. Universally, tropical areas accept water maximum contaminant levels developed by temperate nations, despite the obvious differences in tropical climates. High densities of total and fecal coliform bacteria have been detected in pristine streams and in groundwater samples collected from many tropical parts of the world, even in epiphytic vegetation 10 m above ground in the rain forest of Puerto Rico. Nucleic acid (DNA) analyses of Escherichia coli from pristine tropical environs has indicated that they are identical to clinical isolates of E. coli. Many tropical source waters have been shown to have enteric pathogens in the complete absence of coliforms. Diffusion chamber studies with E. coli at several tropical sites reveal that this bacterium can survive indefinitely in most freshwaters in Puerto Rico. An evaluation of methods for the enumeration of fecal coliforms showed that currently used media have poor reliability as a result of large numbers of false positive and false negative results when applied to tropical water samples. Total and fecal coliform bacteria are not reliable indicators of recent biological contamination of waters in tropical areas. Fecal streptococci and coliphages in tropical waters violate the same underlying assumptions of indicator assays as the coliforms. Anaerobic bacteria like Bifidobacterium spp. and Clostridium perfringens show some promise in terms of survival, but not in ease of enumeration and media specificity. The best course at present lies in using current techniques for direct enumeration of pathogens by fluorescent staining and nucleic acid analysis, and developing tropical maximum contaminant levels for certain resistant pathogens in tropical waters.
Detection and recovery of Legionella in water
Authors: Barbaree J. M. , Morrill W. E. , Fields B. S. , Martin W. T. , Sanden G. N. 
Published: October 2006

AbstractMethods used to detect Legionella include direct fluorescent antibody stain, genetic probe, and culturing. Culturing is preferred for detecting Legionella pneumophila (Lp) in water; however, recovery rates are affected by treatment of water samples. Experiments with water‐containing Lp showed that (a) a water storage temperature of 4°C results in a slower decline in numbers of Lp as compared with 25, 35, and 45°C; (b) a water sample containing Lp and nonlegionellae microflora is appropriate for quality control of selective media used to isolate Legionella from environmental water specimens; and (c) acid treatment and concentration of water by filtration are effective techniques for isolating Lp from environmental water samples, but they do not yield 100% recovery of Lp cells.
Coliphage association with coliform indicators: A case study in Chile
Authors: Castillo Gabriela , Thiers R. , Dutka B. J. , El‐Shaarawi A. H. 
Published: October 2006

AbstractThis paper summarizes the results obtained from an International Development Research Centre (IDRC), Ottawa, Canada, funded study to evaluate the potential of using coliphage as an indicator of water quality. Raw water sample data indicated that the A‐1 test combined with the coliphage test would make an excellent screening program for health hazards in these waters. The superiority of the Presence/Absence test for detecting microbial health hazards in potable water was readily shown, while the H2S paper strip technique was found to be equally efficient for testing potable waters as traditional coliform water quality indicators.
Southeast Asian experiences with the coliphage test
Authors: Suan Sim Tiow , Chuen Ho Yueh , Sivaborvorn Komol 
Published: October 2006

AbstractThe increasing demand for potable water in Southeast Asia warrants the need for a simple, rapid, and economical water quality test that can be used by unskilled personnel to monitor potential fecal contamination of drinking water supplies. The coliphage test is expected to fulfill this need since many advantages can be attributed to this test.In order to evaluate the use of the coliphage test, an intensive study to correlate the results of the coliphage test with three other water quality tests—viz., conventional five‐tube most probable number (MPN) fermentation test, the A1 broth five‐tube MPN test, and the membrane filtration test—was carried out. At least 1000 water samples were examined over a 20‐month period. Results of the tests showed that there is a consistent relationship between coliphages and fecal coliforms in river water, pond water, well water and rainwater, in that coliphages are frequently found when fecal coliforms are detected. On the other hand, correlation analyses have also showed that in water sources that are shallow and turbid due to residual sediments, correlation between coliphages and fecal coliforms was less significant. Further analyses have also indicated that the factors that most affected the coliphage tests were turbidity, pH, and dissolved oxygen. In the process of evaluating the coliphage procedure, it was found that the test can be performed at ambient temperatures and results can be obtained after 6–8 h of incubation.
Removal of cyanobacterial toxins in water treatment processes: Laboratory and pilot‐scale experiments
Authors: Keijola A. M. , Himberg K. , Esala A. L. , Sivonen K. , Hiis‐Virta L. 
Published: October 2006

AbstractThe effectiveness of various drinking water treatment processes has been tested in laboratory and pilot scale experiments using neurotoxic and hepatotoxic cyanobacterial blooms and laboratory‐grown algal cultures as test material. The species involved belonged to the genera Microcystis, Oscillatoria, and Anabaena. Microcystis and Oscillatoria hepatotoxins were analyzed by high performance liquid chromatography. The Anabaena neurotoxin, anatoxin‐a, was determined using gas chromatography/mass spectrometry techniques. Toxicity was tested and verified by mouse bioassay. The laboratory study, made with freeze‐dried cyanobacteria, showed that toxins were not removed by conventional flocculation treatment procedures. The simultaneous addition of a small amount of powdered activated carbon with the flocculation chemical did not improve the removal of hepatotoxins significantly. Substantial reduction of toxins was achieved by granulated activated carbon filtration and by ozonization. Pilot plant studies supported the laboratory findings. Results of the slow sand filtration experiments suggested some removal of toxins.
Annual variation and reliability of fecal indicators in a polluted river
Authors: Niemi R. M. , Niemi J. S. 
Published: October 2006

AbstractFecal indicators were enumerated over a period of one year in the river Vantaanjoki discharging to the Gulf of Finland. The river was divided into three zones, one affected by nonpoint loading, another receiving treated domestic sewage, and the lower reach with no substantial further loading. The reliability of routine enumeration methods for thermotolerant coliforms and fecal streptococci was tested by isolating strains for confirmation.Fecal indicators showed wide spatial and temporal variation: the concentrations and numbers were low in summer, higher in winter under the ice cover, and highest during the periods of high discharge in spring and autumn.Of the 931 thermotolerant coliforms isolated, 74% were identified as Escherichia coli by the API 20 E identification system. A total of 3441 strains were tested for gas and indole production at 44.5°C. Of these, 73% were gas positive and 89% indole positive. Of the 3567 fecal streptococci, 67% were confirmed as catalase negative and esculin positive on bile esculin azide agar at 44.5°C. The proportion of confirmed fecal indicators varied both in different reaches of the river and seasonally. The enumeration of fecal streptococci was in some cases unreliable.Correlations between different fecal indicators and between fecal indicators and chemical water quality variables were calculated within seasons. Correlation coefficients varied with season but showed good overall compatibility.
Toxicity of a trivalent organic arsenic compound, dimethylarsinous glutathione in a rat liver cell line (TRL 1215)
Authors: Sakurai T , Kojima C , Kobayashi Y , Hirano S , Sakurai M H , Waalkes M P , Himeno S 
Published: October 2006

Background and purpose:Although inorganic arsenite (AsIII) is toxic in humans, it has recently emerged as an effective chemotherapeutic agent for acute promyelocytic leukemia (APL). In humans and most animals, AsIII is enzymatically methylated in the liver to weakly toxic dimethylarsinic acid (DMAsV) that is a major pentavalent methylarsenic metabolite. Recent reports have indicated that trivalent methylarsenicals are produced through methylation of AsIII and participate in arsenic poisoning. Trivalent methylarsenicals may be generated as arsenical–glutathione conjugates, such as dimethylarsinous glutathione (DMAsIIIG), during the methylation process. However, less information is available on the cytotoxicity of DMAsIIIG.Experimental approach:We synthesized and purified DMAsIIIG using high performance TLC (HPTLC) methods and measured its cytotoxicity in rat liver cell line (TRL 1215 cells).Key results:DMAsIIIG was highly cytotoxic in TRL 1215 cells with a LC50 of 160 nM. We also found that DMAsIIIG molecule itself was not transported efficiently into the cells and was not cytotoxic; however it readily became strongly cytotoxic by dissociating into trivalent dimethylarsenicals and glutathione (GSH). The addition of GSH in micromolar physiological concentrations prevented the breakdown of DMAsIIIG, and the DMAsIIIG‐induced cytotoxicity. Physiological concentrations of normal human serum (HS), human serum albumin (HSA), and human red blood cells (HRBC) also reduced both the cytotoxicity and cellular arsenic uptake induced by exposure to DMAsIIIG.Conclusions and implications:These findings suggest that the significant cytotoxicity induced by DMAsIIIG may not be seen in healthy humans, even if DMAsIIIG is formed in the body from AsIII.British Journal of Pharmacology (2006) 149, 888–897. doi:10.1038/sj.bjp.0706899
Triggering CD40 on endothelial cells contributes to tumor growth
Authors: Chiodoni Claudia , Iezzi Manuela , Guiducci Cristiana , Sangaletti Sabina , Alessandrini Isabella , Ratti Chiara , Tiboni Francesca , Musiani Piero , Granger D. Neil , Colombo Mario P. 
Published: October 2006

Inflammatory cells can either promote or inhibit tumor growth. Here we studied whether CD40, a key molecule for adaptive immune response, has any role in mammary carcinogenesis of BALB/NeuT transgenic tumor-prone mice. We transferred the HER2/neu oncogene into CD40-null background to obtain the CD40-KO/NeuT strain. CD40-KO/NeuT mice showed delayed tumor onset and reduced tumor multiplicity. BM (BM) transplantation experiments excluded a role of BM-derived cells in the reduced tumorigenicity associated with CD40 deficiency. Rather, CD40 expressed by endothelial cells (ECs) takes part to the angiogenic process. Accordingly, large vessels, well organized around the tumor lobular structures, characterize BALB/NeuT tumors, whereas tiny numerous vessels with scarce extracellular matrix are dispersed in the parenchyma of poorly organized CD40-KO/NeuT tumors.
Activated platelets, which may interact with and activate ECs, are a possible source of CD40L. Their localization within tumor vessels prompted the idea of treating BALB/NeuT and CD40-KO/NeuT mice chronically with the anti-platelet drug clopidogrel, known to inhibit platelet CD40L expression. Treatment of BALB/NeuT mice reduced tumor growth to a level similar to CD40-deficient mice, whereas CD40-KO/NeuT mice treated or not showed the same attenuated tumor outgrowth, indicating that activated platelets are the likely source of CD40L in this model. Collectively, these data point to a participation of CD40/CD40L in the angiogenic processes associated with mammary carcinogenesis of BALB/NeuT mice.