bluuebunny/crossref_metadata_2025 huggingface dataset:
Multivariate Characterization and Modelling of the Chemical Reactivity of Epoxides. Part II: Extension to Di‐ and Trisubstitution
Authors: Eriksson Lennart , Verhaar Henk J. M. , Sjöström Michael , Hermens Joop L. M.
Published: October 2006

The chemical reactivity toward 4‐nitrobenzylpyridine (4‐NBP) of a series of twelve mono‐, di‐ and trisubstituted epoxides has been modelled by means of multivariate quantitative structure‐property relationships (QSPRs). The models were established using theoretical descriptor variables and partial least squares (PLS) analysis. It was found that a multivariate set of eleven descriptor variables was sufficient to adequately model the chemical reactivity. Furthermore, there existed a non‐linear relationship between the theoretical descriptors and the chemical reactivity. Two‐component PLS models were generally required, using the second component to compensate for non‐linearity in the first. The nature of the non‐linearity suggests that different physico‐chemical factors are regulating the chemical reactivity among two observed subgroups of epoxides. The reactivity of one group of five epoxides with one non‐substituted ring carbon is regulated by the electronegative properties of the substituent on the other ring carbon, whereas the reactivity of seven di‐ and trisubstituted epoxides depends on a combination of the substitution pattern around the epoxide ring and the size of these substituents. Two additional points of general relevance for QSPR modelling are also addressed, namely predictor variable selection and appropriate transformation of the dependent variable.
Relation between the Odor of (R)‐Ethyl Citronellyl Oxalate and its Stable Conformations
Authors: Yoshii Fumiko , Hirono Shuichi , Moriguchi Ikuo
Published: October 2006

The complex odor of (R)‐ethyl citronellyl oxalate (ECO) was investigated based on its stable conformations. ECO, a flexible chain‐type compound, mainly has a musk‐like odor, but also has a rose‐like odor. The rose‐like odor recalls citronellol according to a perfumer's sensory evaluation. The conformational analyses of ECO and (S)‐citronellol were performed using CACheTM (Computer Aided Chemistry) system. Structure optimization of selected conformers was performed with the PM3 method in succession. Twenty‐three conformers of ECO were obtained and were compared with the three‐dimensional structure model for benzenoid musks previously proposed and also with 22 stable conformers of (S)‐citronellol. As a result, we found that the two most stable compact conformers of ECO, which were quite similar, fit the structure model for benzenoid musks, and that a three‐dimensional partial structure of another conformer of ECO was similar to one conformer of (S)‐citronellol. Thus, the main odor quality of ECO, the musk‐like odor, could be explained by the most stable compact conformers. We also showed that the secondary odor quality of ECO, a rose‐like odor, was possibly due to one of the stable conformers of ECO that is partially similar to the conformer of (S)‐citronellol.
Quantitative Structure‐Activity Relationships of 2‐Benzamido‐5‐Nitrothiazole Molluscicidal Derivatives
Authors: Vignoles Philipp , Clédat Dominique , Dreyfuss Gilles , Rondelaud Daniel , Pénicaut Bernard
Published: October 2006

The pharmacologic action of 2‐benzamido‐5‐nitrothiazole and eleven derivatives was studied in Lymnaea peregra ovata Müller, Gammarus pulex pulex L., and Euglena gracilis Klebs. The toxicity parameters (50 % lethal concentration, 50 % inhibitory concentration) were correlated with the physicochemical parameters of the compounds (lipophilicity, stability). The toxicity of the molecule was related to its lipophilicity and stability. By combining these parameters it was possible to establish specific equations for each species studied. Linear equations of the overall parameters of the molecule were obtained with L. p. ovata and E. gracilis, whereas second‐degree relationships were found with G. p. pulex. Using these pharmacokinetics models, it is possible to predict the pharmacologic action of these compounds knowing only the physicochemical parameters of each molecule.
Physicochemical Significance of Topological Parameters, Connectivity Indices and Information Content. Part 1: Correlation Studies in the Sets with Aromatic and Aliphatic Substituents
Authors: Saxena Anil K.
Published: October 2006

Topological parameters like 1x, 2xv and IC1 are used in QSAR studies because of their simplicity of calculation. In the absence of their physicochemical significance, it is difficult to interpret the results of such QSAR studies in terms of mode or mechanism of action of the bioactive molecule. Keeping this in view, attempts have been made to interpret the empiricism of these parameters. The physicochemical significance of these parameters has been studied in different sets of compounds having one physicochemical parameter constant in each set. It has been observed that the connectivity index correlated to a greater extent with molar refractivity (MR) than with hydrophobic (π) or logP which may be due to the inherent relationship between MR, molecular weight, numbers of non‐hydrogen atoms in the molecule, surface, volume 1x and 2xv values. The information content did not show correlation with any of the physicochemical parameter considered.
Quantitative Structure‐Time‐Activity Relationships (QSTAR): Growth Inhibition of Escherichia coli by Nonionizable Kojic Acid Derivatives
Authors: Piršelová Katarína , Baláž Štefan , Ujhelyová Regina , Šturdík Ernest , Veverka Miroslav , Uher Michal , Brtko Július
Published: October 2006

A semi‐empirical model for quantitative structure‐time‐activity relationships (QSTAR) has been applied to the data on inhibition of Escherichia coli in a batch culture in seven media of different acidity (pH 5.6 – 8.0) by twenty one nonionizable derivatives of kojic acid (5‐hydroxy‐2‐hydroxymethyl‐4H‐pyrane‐4‐one). The antibacterial potency of individual derivatives was characterized by the equieffective concentrations causing the 50%‐decrease in the specific growth rate in comparison with the untreated control. The QSTAR models satisfactorily describe toxicity of the studied compounds as a model‐based non‐linear function of hydrophobicity, the size of the substituents in the position 2, and the time of exposure. The dependence of the antibacterial activity on hydrophobicity at a fixed exposure time exhibits a broad maximum: the decrease for hydrophilic compounds is caused by their diminished ability for binding to the receptors and that for hydrophobic compounds is elicited by their lower concentrations in the aqueous phases and their slower inactivation. Inactivation is probably enzymatic because its rate depends on the size of the molecules. The size has a positive effect also on the binding to the receptor.
Comparative Molecular Field Analysis (CoMFA) of MX Compounds using different Semi‐empirical Methods: LUMO Field and its Correlation with Mutagenic Activity
Authors: Navajas Cecil , Poso Antti , Tuppurainen Kari , Gynther Jukka
Published: October 2006

In the present paper we make a comparison among three different semi‐empirical methods (AMI, MNDO and PM3) for the optimization of the geometries and calculation of different properties of MX compounds. The results were used to develop a CoMFA model to correlate the TA100 mutagenicity of these compounds with the LUMO field. The correlations between the LUMO field and steric, electrostatic and CoMFA fields generated automatically by the SYBYL CoMFA program, were explored. A comparison among different values of grid spacing for the lattice and standard deviation thresholds for column filtering was carried out to select the best values for this and future work.

The results indicate that AM1 and PM3 methods represent a real improvement over MNDO in respect to QSAR studies relating electronic properties and mutagenicity for these compounds.
Inhibition of Bilirubin UDP‐glucuronosyltransferase: A Comparative Molecular Field Analysis (CoMFA)
Authors: Said Mourad , Ziegler Jean‐Claude , Magdalou Jacques , Elass Abdelaziz , Vergoten Gérard
Published: October 2006

Two series of compounds structurally related to phenolphthalein and triphenylalkyl carboxylic acid were tested as inhibitors of bilirubin glucuronidation catalyzed by rat liver microsomal UDP‐glucuronosyltransferase, and analyzed by the CoMFA method in order to predict the inhibitory potency of these structures and afford a three dimensional structure of the bilirubin binding site. These substances could inhibit bilirubin glucuronidation to different extents. Their inhibitory potency was quantitated in terms of I50 values. The best inhibitors exhibited competitive inhibition. The 3D‐QSAR results led to a fairly good prediction of the inhibitory potency of these two series of compounds. They indicate a correlation between the inhibitory activity of the glucuronidation reaction and the steric and electrostatic fields with a relative contribution of 43% and 57%, respectively.
Comparative Molecular Field Analysis of HIV‐1 Reverse Transcriptase Inhibitors in the Class of 1[(2‐Hydroxyethoxy)‐methyl]‐6‐(phenylthio)thymine
Authors: Hannongbua Supa , Lawtrakul Luckhana , Sotriffer Christoph A. , Rode Bernd M.
Published: October 2006

A Comparative Molecular Field Analysis of 40 HEPT (1‐[(2‐Hydroxyethoxy)‐methyl]‐6‐(phenylthio)thymine) analogues was performed. The 3D‐QSAR study correlates steric and electrostatic fields of the compounds with HIV‐1 RT inhibition, resulting in a model which has a high predictive ability. CoMFA results revealed that steric interaction explains a majority (70%) of the variance in the data. Using only steric interaction energy in the analyses provided a better predictive model. Inclusion of electrostatic descriptors in terms of coulomb interaction energies deteriorates the results. However, it was found in this study that variation of sp3 O charges had some influence on r and that the interaction energies using sp3 O probe with a charge of −0.3 led to the best predictive model.
Test Series Selection from Nonlinear Neural Mapping
Authors: Domine Daniel , Devillers James , Wienke Dietrich , Buydens Lutgarde
Published: October 2006

A new nonlinear neural mapping (N2M) technique based on the combined use of Kohonen self‐organizing map (KSOM), minimum spanning tree (MST), and nonlinear mapping (NLM) is introduced for optimal test series selection. With the N2M method, KSOM results are enhanced by the visualization of the actual distances between the loaded neurons from MST and NLM. N2M provides an easily interpretable and comprehensible graphical display which guides the selection of representative test series especially when the number of individuals is high. In addition, structure‐activity relationships can be derived. The approach is open since any information useful for data interpretation can be plotted by means of graphical tools.
Quantitative Structure‐Property Relationships of Azurin Mutants from Pseudomonas Aeruginosa
Authors: Norinder Ulf , Karlsson B. Göran , Sjölin Lennart , Pascher Torbjörn , Bonander Nicklas
Published: October 2006

The method of partial least squares projections to latent structures (PLS) has been used to derive quantitative relationships between measured reduction potentials and structures of some Pseudomonas aeruginosa azurin mutants with changes in position 121. The models indicate that relatively few properties of the amino acids explain the experimental results obtained. Electronic characteristics exert a major influence on the models but also factors associated with acid‐base strength, lipophilicity as well as with hydrogen bonding have large impact. The calculations also show that no single amino acid, natural or synthetic, can meet all of the optimum requirements of position 121 but indicate that a fine balance between various factors is a necessary prerequisite for a proper choice of residue to obtain a mutant with the desired properties.
Stepwise Leave‐One‐Isomer‐Out Free‐Wilson Approaches as Preprocessing Tools in QSAR Analysis of Racemates
Authors: Dove Stefan , Buschauer Armin
Published: October 2006

QSAR analysis of racemates is complicated if specific substituent‐receptor interactions and, by that, specific spatial fits to the binding site result in individual but unknown activity differences of enantiomers, and even in structure‐dependent changes of which is the more active configuration. In a first approximation, additivity of substituent contributions should be assumed instead of major conformational effects. Then, Free‐Wilson analysis (FWA) can be used as preprocessing tool to reduce a starting set of all pairs of enantiomers into a final series of the probably (more) active configurations. A stepwise “leave‐one‐isomer‐out” approach is applied, where the model is successively improved by checking all remaining pairs and leaving out one enantiomer, determined by a special criterion of poorest prediction, in each step. The final model is given by the maximal F value. This approach was applied to histamine H1 antagonistic activity (pKB, guinea pig ileum) of 19 racemic and six non‐chiral phenyl‐halogenated N‐(diphenylpropyl)‐N′‐(imidazolylpropyl)guanidines. Based on only eight variables because of additivity of meta and para contributions, the starting model with n = 44, r2 = 0.29, s = 0.52, F = 1.8, r2‐PRESS = −0.14 has been improved to a final one with n = 31 (only six remaining pairs), r2 = 0.84, s = 0.24, F=14.0, r2‐PRESS = 0.65. Additionally, each of the successive series was submitted to CoMFA. Statistical parameters of the parallel CoMFA and FWA models are closely related. QSAR results obtained with both methods correspond to well‐known structure‐activity relationships of diphenhydramine‐like H1 antagonists. A direct application of the leave‐one‐isomer‐out strategy to CoMFA was less successful.
Quantitative Structure‐Activity Relationship Studies on Some Acyclouridine Derivatives Acting as Anti‐HIV‐1 Drugs
Authors: Garg Rajni , Kurup Alka , Gupta S. P.
Published: October 2006

The anti‐HIV‐1 activity of some derivatives of 1‐[2‐hydroxyethoxy]‐6‐(phenylthio)thymine(HEPT) is analyzed in relation to their physicochemical and molecular properties. The activities of the compounds are found to be significantly correlated with hydrophobic constant π and the van der Waals volume Vw. The results are found to be useful in discussing the mechanism of drug‐receptor interaction.
Modelling of the CCK Antagonist Activity of Benzodiazepines on Pancreatic Receptors
Authors: Huché Michel , Legendre Jean‐Jacques
Published: October 2006

The pancreatic CCK antagonist activity of 73 benzodiazepines was studied by molecular modelling. Construction and optimisation by GenMol and MOPAC allowed us to obtain molecules of absolute minimum energy. Seven geometrical parameters and pharmacophores were selected for a processing by neuronal system. They allow a good prediction of activity of a compound belonging to this series: the correlation coefficients are 0.971 for the calculation and 0.952 for the prediction. A second database, limited to 23 compounds, constituted by a sample of the former one, allowed us, by selecting four parameters to obtain a satisfactory linear and not‐linear correlation for these compounds. The correlation coefficients obtained by neuronal system are 0.977 for the calculation and 0.967 for the prediction.
Mutual view sharing system for real‐time telecommunication
Authors: Nishikawa Atsushi , Kijima Shigeo , Katoh Tomohiro , Maruya Masachika , Yamaguchi Satoshi , Yamazaki Fumio
Published: October 2006

Owing to the widespread use of the Internet and portable phones, long‐distance human communication is becoming convenient and is being widely used in daily life. In particular, with portable phones, real‐time voice communications can be realized between widely separated locations, regardless of where, and at any time. This paper proposes a real‐time remote communications support system (mutual view‐sharing system) in which the views seen by the parties can be shared in real time by means of an eyeglass‐type face‐mounted display, a small camera attached above the eye of the user, and a wearable PC. When this system is used to communicate with another party at a distant location, the displays on both sides maintain the same “shared view.” The “shared view,” in which one party's view is shared with the other party, contains the image obtained from one party's face‐mounted camera and also an image of the hand of the other party. When the view of the other party is shared, the “shared view” combines the image obtained from the face‐mounted camera of the other party and also the speaker's own hand image. This mechanism makes it possible, even if the other party is at a distant location, to share a view of the subject of the conversation visually and to transmit positional information on the subject by means of pointing gestures. The system is completely wearable, and the parties communicate while appropriately switching between the shared views. Thus, the system can be considered as an extension of the portable phone. This system was used to perform a real‐time remote communications experiment with the content of “asking the other party to find an object.” It was shown that the system is especially useful compared to voice‐only communications when the shape of the subject of the conversation is complex and the other party has no knowledge of the subject. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(14): 73–86, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20460
Noise reduction of speech signals by running spectrum filtering
Authors: Fujioka Kazuma , Hayasaka Noboru , Miyanaga Yoshikazu , Yoshida Norinobu
Published: October 2006

This paper proposes a new noise reduction method intended for noise reduction in speech. The method combines running spectrum filtering (RSF) based on the different time variations of the power spectrum between speech and noise, and postprocessing to reduce musical noise. RSF is a filter which is realized in the modulation spectrum and can effectively reduce noise when applied to the running spectrum of speech. In this paper, it is shown that the segmental SNR of the speech with noise used in the experiment can be improved. A subjective listening experiment shows that the quality of speech degraded by noise is improved. © 2006 Wiley Periodicals, Inc. Syst Comp Jpn, 37(14): 52–61, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.20529
ARXPS characterisation of plasma polymerised surface chemical gradients
Authors: Parry K. L. , Shard A. G. , Short R. D. , White R. G. , Whittle J. D. , Wright A.
Published: October 2006

The aim of this paper is twofold: first to report on the lateral and vertical characterisation of a surface chemical gradient of carboxylic‐acid functionality and second, to demonstrate the use of said gradient to probe the passive adsorption of immunoglobulin G (IgG) as a function of the density of surface carboxylic‐acid groups.

A surface chemical gradient of carboxylic‐acid functionality was fabricated by the plasma copolymerisation of octadiene (OD) and acrylic acid (AA). The plasma‐polymerised gradient was over 12 mm, with 2 mm of plasma‐polymerised OD at one end and 2 mm of plasma‐polymerised AA at the other. By means of linescan angle resolved x‐ray photoelectron spectroscopy (ARXPS) it is shown precisely how acid functionality varies from the 2 mm position (OD end) on the gradient to the 10 mm position (AA end). By recording data from 16 angles at each of the 25 sampling points along the gradient, it is shown that the surface gradient also changes vertically, most notably in the thickness of the plasma polymer. At the OD end the plasma‐polymerised layer is 6.3 nm thick, while at the AA end the plasma‐polymerised layer is 5 nm. More subtle changes in chemistry through the plasma‐polymerised layer are shown at the 7.5 and 10 mm points.

An identical gradient is used to probe IgG adsorption along the length of the gradient. ARXPS is used to monitor the nitrogen 1s (N1s) signal at 25 points, the N1s signal being unique to adsorbed IgG. It is demonstrated that IgG adsorbs in far greater amount (IgG per unit area) at the OD end, and the amount of adsorbed IgG decreases along the length of the gradient. It is estimated that >200 ng/cm2 adsorbed at the OD, while at the AA the amount adsorbed was <20 ng/cm2. Copyright © 2006 John Wiley & Sons, Ltd.
The relative sensitivity of microtox®, daphnid, rainbow trout, and fathead minnow acute lethality tests
Authors: Munkittrick K. R. , Power E. A. , Sergy G. A.
Published: October 2006

Relative sensitivity and correlations between the Microtox® test and three commonly used acute lethality bioassays (i.e., rainbow trout, fathead minnow,Daphnia) are reviewed and discussed. All relevant data available for comparison were separated and evaluated based on chemical groupings. Generally, Microtox was more sensitive than or as sensitive as the acute lethality tests for pure individual organics, but was less sensitive to most inorganics. Microtox was not as sensitive as acute lethality tests to effluents or leachates with a high component of insecticides, herbicides, inorganics, pharmaceuticals or textiles, or highly lipophilic contaminants. As the complexity and toxicity of industrial effluents increased, the correlations and sensitivity of Microtox increased, with a corresponding decrease in data variability. Additionally, limitations of the available data are that (1) comparisons of relative sensitivity varied with the compounds and organisms tested; (2) there was a lack of standardization in approach and a failure to provide adequate details on the origin of the cited toxicity data, which confused and obscured comparisons; and (3) published reviews commonly failed to identify fish species and test details for cited data.
Inhibition of bioluminescence in a recombinant Escherichia coli
Authors: Rychert Robert , Mortimer Michael
Published: October 2006

Six toxicants were evaluated for their ability to inhibit bioluminescence in a recombinant Escherichia coli harboring pJE202 that contained the lux (light‐producing) genes. With the recombinant E coli. the rank order for toxicity was Zn2+ > ethidium bromide > sodium pentachlorophenate > Cu2+ > 2,4‐dichlorophenoxyacetic acid. The light‐producing recombinant E. coli was insensitive to sodium dodecyl sulfate, and was much less sensitive than the Microtox test with the six toxicants. These results do not preclude the use of recombinant bacteria in toxicity testing.
Ecological effects of hepatotoxic cyanobacteria
Authors: Lindholm T. , Eriksson J. E. , Reinikainen M. , Meriluoto J. A. O.
Published: October 2006

Many species of cyanobacteria produce hepatotoxic peptides called microcystins. Toxic cyanobacteria have caused fish, wildlife, and cattle mortality in many countries, but the distribution and fate of toxins and their ecological effects are poorly known. Toxic cyanobacteria may affect sensitive organisms and populations, but also fundamental ecological processes, e.g., primary production and microbial activity. Many studies show negative effects of cyanobacteria on zooplankton, but information on the type and quantity of toxin(s) involved is usually missing. Mussels accumulate peptide toxins but accumulation in other organisms remains to be studied. Cyanobacterial blooms often affect the littoral zones, which are important reproduction and feeding areas for fish and birds.
Toxicity of edible mussels (Mytilus edulis) growing naturally in an estuary during a water bloom of the blue‐green alga Nodularia spumigena
Authors: Falconer I. R. , Choice A. , Hosja W.
Published: October 2006

Possible accumulation of toxicity by edible mussels growing in a water bloom of Nodularia was investigated during the annual eutrophication of a brackish/marine water estuary in Western Australia. At a cell density of 100,000 cells/mL water, during the growth phase of the bloom, the gut and gut contents of mussels showed the highest toxicity of about 90 mg dry weight of tissue lethal to 1 kg mice by sterile (boiled) i.p. injection. Death was due to hepatotoxicity. It was concluded that edible mussels should not be collected for human consumption during a toxic blue‐green algal bloom.
Effect of suspended aggregate sizes on the adsorption of water‐soluble dyes in an aquatic environment
Authors: Rao S. S. , Maguire R. J. , Krishnappan B. G. , Weng J.‐H. , Ongley E. D.
Published: October 2006

Suspended aggregates from the Yamaska River in Quebec have been separated into several fractions from 3 to <88 μm using size fractionation technique, and these fractions were analyzed for their bacterial, particulate organic carbon and nitrogen content, as well as their ability to adsorb two water‐soluble dyes. The results indicate that the suspended bacterial aggregates are capable of adsorbing and thus transporting significant quantities of these dyes in river water. The maximum contaminant dye adsorption occurred within the 24‐h period for Acid Orange 60. Implications of bacterial‐mediated contaminant transport in aquatic environments are indicated. © 1992 John Wiley & Sons, Inc.
Issues in fishery products safety in the united states
Authors: Ahmed Farid E.
Published: October 2006

Most seafoods available to the U.S. public are wholesome and unlikely to cause illness in the consumer. Nevertheless, there are areas of risk. The major risk of acute disease is associated with the consumption of raw shellfish, particularly bivalve molluscs. For persons living in tropical areas, there is a risk of ciguatera; other natural toxins (paralytic shellfish poisoning, neurotoxic shellfish poisoning, etc.) have been associated with shellfish from endemic areas. Finally, there are less well‐defined risks of acute and chronic disease related to environmental contamination of aquatic food animals. Dealing with such risks on a short‐term basis requires improvements in the present system of regulatory control. In the long term, amelioration and eventual elimination of some hazards require strengthening and more effective application of control measures to prevent the disposal of human and industrial waste into offshore marine and fresh waters. © 1993 John Wiley & Sons, Inc.
Genotoxicity of chlorine‐treated amino acids
Authors: Nakamura Sei‐Ichi , Ugawa Masahiro , Obana Hirotaka
Published: October 2006

Chlorine treatment, a commonly used disinfection procedure, was found to produce genotoxic amino acid derivatives. The umu testing using Salmonella typhimurium TA1535/pSK1002 carrying the umuC‐lacZ fusion gene, in which genotoxicity can be detected in terms of β‐galactosidase activity, was used to examine chlorine‐treated amino acids. Ten of the 14 L‐amino acids tested (arginine, glycine, histidine, hydroxyproline, lysine, methionine, phenylalanine, proline, serine, threonine) showed genotoxicity after reaction with chlorine, while alanine, isoleucine, leucine, and valine did not. © 1993 John Wiley & Sons, Inc.
Intoxication of euglena cells by tributyltin chloride and its detoxication by pretreatment with high electric field loaded water
Authors: Suzuki Tetsuya , Takahashi Nozomu , Fukunaga Kenji , Okamura Mutsuo , Tanaka Tatsuro , Takama Kozo
Published: October 2006

Pollution of the marine environment by the antifouling organotin compounds such as tributyltin chloride (TBTCl) and tributyltin oxide (TBTO) is of concern to the public health and ecosystem stability. Consequently, there is a need to develop means for the decontamination of tin‐intoxicated biota.

In the present study, we used Euglena gracilis Z as a model organism to investigate the effect of various pretreatments on the restoration of TBTCl intoxicated cells. A brief exposure of Euglena cells to TBTCl (5 × 10–4−10−6 M), cells were found to change their shape into cyst form, and became almost inactive within a few minutes. TBTCl was rapidly incorporated into the Euglena cell, and was largely located in the cytosol + microsomes fraction. When TBTCl‐intoxicated Euglena cells were transferred into organotin free medium, TBTCl content in the cells decreased. However, cells neither regained motility nor did their shape return to normal. When the intoxicated cells were incubated in water that was prepared by being loaded with high voltage condenser electric potential of 12 kV for 70 h, the cells regained motility, and their shape returned to almost normal by excluding tin prior to regaining motility. The study results may lead to a practical means for the decontamination of polluted biota. © 1993 John Wiley & Sons, Inc.
Levels of heavy metals in biota from the la plata river
Authors: Verrengia Guerrero Noemí R. , Kesten Eva M.
Published: October 2006

In this study levels of five heavy metals—Cd, Cu, Ni, Pb, and Zn—were quantified in selected tissues of aquatic organisms and in sediments from the La Plata River. Fishes (Odontesthes bonariensis and Pimelodus clarias), snails (Ampullaria insularum), and bivalve molluscs (Neocorbicula limosa) were collected from a Recreational Fishing Association, nearby Buenos Aires harbor, during 1988 and 1989.

Samples of snail hepatopancreas showed higher levels of metal concentrations than samples of fish livers, regarding the five metals quantified. In general, lower levels of heavy metals were observed in whole body samples of bivalves, with or without the gut contents, except for Cd. Both species of macroinvertebrates have demonstrated a great ability to bioaccumulate Cd.

Many physical, chemical, and biological factors regulate the intake and accumulation of heavy metals by aquatic organisms. Therefore, it is difficult to assess the extent of pollution in biota from the La Plata River by direct comparisons with data previously reported in the literature. However, our results may be useful as reference levels of heavy metal contamination in selected organisms from this particular aquatic system. © 1993 John Wiley & Sons, Inc.
Enzyme‐linked immunosorbent assay for detection of highly virulent strains of aeromonas hydrophilia and aeromonas sobria in water
Authors: Merino Susana , Camprubi Silvia , Regué Miguel , Tomás Juan M.
Published: October 2006

A microtitration plate, antibody capture, enzyme‐linked immunosorbent assay was developed for detection of Aeromonas hydrophila and sobria serotype 0:11 (highly virulent strains). The assay utilizes a detector antibody that shows no cross‐reactions with Aeromonas strains not belonging to serotype 0:11 or non‐Aeromonas competing organisms. All the A. hydrophila and sobria strains from serotype 0:11 tested reacted strongly with the detector antibody. Also, by culturing and performing the immunoassay on a filter with the detector antibody, we can quantify A. hydrophilia or sobria 0:11 cells/100 mL of water.
Biodegradation of pentachlorophenol by micromycetes. III. Deuteromycetes
Authors: Benoit‐Guyod Jean‐Louis , Seigle‐Murandi Françoise , Steiman Regine , Sage Lucile , Toe Adama
Published: October 2006

A third study on the biodegradation of pentachlorophenol (PCP) (100 mg L−1) by micromycetes was done with 784 strains of Deuteromycetes cultivated in liquid synthetic medium. The disappearance of PCP after 5 days of cultivation was compared with POx production. Mean PCP depletion was 56% for Agonomycetales, 60% for Coelomycetes, 51% for Dematiaceae, 52% for Mucedinaceae (other thanAspergillusandPenicillium), 56 and 57%, respectively, forAspergillusandPenicillium, and 42% for Tuberculariales. Although some genera gave homogeneous results (Ascochyta, Aspergillus, Coniothyrium, Penicillium), a great variability was observed as well in PCP depletion as in POx production, reflecting the heterogeneity of this artificial taxonomic group. With a few exceptions, correlation between POx production and PCP disappearance was low or nonexistent. Another factor, probably not enzymatic, could be involved. ©1994 by John Wiley&Sons, Inc..
The influence of sediment extract fractionation methods on bioassay results
Authors: Ho Kay T. , Mills Lesley J. , Mueller Cornelia , Anderson Stephanie C. , Malcolm A. Russell
Published: October 2006

Four bioassays [MicrotoxTM, MutatoxTM, sister chromatid exchange (SCE), and metabolic cooperation] were used to analyze marine sediment extracts fractionated by two different methods: silica gel column chromatography and acid–base fractionation. Results indicated that a sediment extract fractionated with different methods can lead to different conclusions about the same sediment.

This research also further evaluated the new, mutagenic, bacterial bioassay Mutatox. Mutatox generally correlated with SCE and the Salmonella typhimurium assays. This rapid, operationally simple bioassay has potential as a screening bioassay to detect genotoxic agents. © 1994 by John Wiley & Sons, Inc..
A method to assess the toxicity of pollutants on anaerobic microbial degradation activity in sediments
Authors: Remde Armin , Traunspurger Walter
Published: October 2006

A method to assess the impact of toxicants on the actual anaerobic microbial degradation activity in sediments is described. Under conditions closely related to in situ, the influence of isoproturon and three of its known metabolites on the actual carbon dioxide release rate and the actual methane production rate was determined. For isoproturon only a slight inhibition ( < 10%) of the methane production rate was observed at concentrations up to 6.25 mg/L. All tested metabolites of isoproturon significantly inhibited the methane production rate (up to 70%) at concentrations of 50–500 μg/L. Complete inhibition of methanogenesis did not affect the anaerobic mineralization rate measured as carbon dioxide release in the investigated sediment. Neither isoproturon nor the tested metabolites affected the carbon dioxide release rate. © 1994 by John Wiley & Sons, Inc..
Lysosomes as cellular markers of environmental pollution: Time‐ and dose‐dependent responses of the digestive lysosomal system of mussels after petroleum hydrocarbon exposure
Authors: Cajaraville M. P. , Abascal I. , Etxeberria M. , Marigómez I.
Published: October 2006

Lysosomes are cell organelles containing hydrolytic enzymes and involved in intracellular digestion. Numerous environmental contaminants can interfere with lysosomes, and the purpose of the present work was to quantify changes induced by petroleum hydrocarbons on the structure of the lysosomal system of mussel digestive cells. Mussels, Mytilus galloprovincialis Lmk., were exposed for three months to the water accommodated fraction (WAF) of two crude oils (URAL and MAYA) and of a lubricant oil. Three different exposure doses (0.6, 6, and 40% WAF) were used for each type of hydrocarbon and mussels were sampled at different time intervals (days 21, 49, and 91). A stereological study, using an automated image analysis system, was made on sections stained for demonstration of β‐glucuronidase activity and four parameters were calculated: lysosomal volume density, surface density, surface to volume ratio, and numerical density. The results indicate that the effect of the exposure dose on lysosomal structure is variable and there is no linear relationship of lysosomal changes with dose. Regarding the effect of the exposure time, two different responses were evidenced: (a) a short‐term response (at day 21) with a decrease in size and numbers of lysosomes and (b) a long‐term response (at days 49 and 91) with an increase in lysosomal size and a decrease in their numbers. The short‐term response may be due to a disintegration process of the digestive cells with subsequent loss of lysosomes and could represent an adaptative response to hydrocarbon exposure. At long exposure times, lysosomal changes, apparently caused by fusion processes giving rise to enlarged lysosomes, correspond to a “general stress response”. © by John Wiley & Sons, Inc.
Screening for sediment toxicity in the Rio Santiago basin: A baseline study
Authors: Ronco Alicia E. , Sobrero M. Cecilia , Rossini Gustavo D. Bulus , Alzuet Pablo R. , Dutka Bernard J.
Published: October 2006

Toxicity testing of sediment samples from the Rio Santiago and its main tributaries was performed using a battery of tests that included the ECHA dipstick biocide monitor, the MetPad test, the lettuce seed germination and the root elongation test, the nematode test, spot plate test, and the SOS Chromotest. Assessment was carried out on organic extracts, pore water, and direct sediment. Results of bioassays showed toxicity sources from tributaries and canals flowing into the river and areas being degraded by insults from industrial spills. © by John Wiley & Sons, Inc.
Toxicity estimation of treated coke plant wastewater using the luminescent bacteria assay and the algal growth inhibition test
Authors: Peter Simone , Siersdorfer Christof , Kaltwasser Heinrich , Geiger Markus
Published: October 2006

Among several bioassays, the Scenedesmus subspicatus chlorophyll fluorescence test and the Photobacterium phosphoreum bioluminescence assay were selected to examine their applicability for toxicity evaluation of changes in coke plant effluent quality. In addition to the ecotoxicological parameters, a chemical analysis of dissolved organic carbon (DOC), ammonia‐N, and nitrate‐N was performed.

It was demonstrated that the toxicity values obtained from the bioassays give a first indication on potential hazard and successful treatment. Decreasing toxicity values went along with decreasing DOC or ammonia‐N values, but the sensitivity toward DOC reduction was higher. Sensitivity toward pure compounds was assessed by comparing the EC50 values of the luminescent bacteria assay with the corresponding EC50 values of the algal bioassay. The data showed a poor correlation between the two bioassays. © by John Wiley & Sons, Inc.
Effects of esfenvalerate pulse‐exposure on the survival and growth of larval Australian crimson‐spotted rainbow fish (Melanotaenia fluviatilis)
Authors: Barry M. J. , Logan D. C. , Ahokas J. T. , Holdway D. A.
Published: October 2006

The effects of very short pulse‐exposures with the synthetic pyrethroid esfenvalerate on survival and growth of larval crimson‐spotted rainbow fish (Melanotaenia fluviatilis) were investigated in two series of experiments. Larval rainbow fish [2, 7, or 14 days (d) old] were pulse‐exposed to esfenvalerate (30–700 ng L−1) for 1 h and then transferred to growth chambers where survival and growth were monitored for periods of 7–28 d, depending on the experimental protocol. Mortality was found to be a more sensitive indicator of pesticide effects than growth. Effects on growth were only observed in treatments where there was significant pesticide‐related mortality. In these treatments, rainbow fish larvae were larger than control larvae. However, as increase in growth was always associated with mortality, it was not possible to determine if this was a direct effect of the pesticide or an artefact of density‐dependent interactions within test populations. There was some evidence to suggest that pulse‐exposure with esfenvalerate at an early age may cause subtle longterm detrimental effects to growth of larval rainbow fish. Dry weight and condition (length/weight) were more sensitive indicators of treatment effect than total length. Esfenvalerate was extremely toxic to larval fish, with 1 h pulse‐exposures as low as 60 ng L−1causing significant mortality. Newly hatched larvae were more sensitive to esfenvalerate than animals that were 14 d old. The effects of esfenvalerate on 7‐d‐old larvae could not be determined because of high control mortality. Larvae of this age undergo transition from endogenous to exogenous feeding and may be more sensitive to handling stress. The lowest 1 h pulse‐exposure esfenvalerate no observed effect concentration and lowest observed effect concentration were <60 and 60 ng L−1respectively, based on 2‐d‐old larval mortality. ©by John Wiley & Sons, Inc.
Isolation, characterization, and physiology of bacteria able to degrade nitrilotriacetate
Authors: Egli Thomas , Weilenmann Hans‐Ulrich
Published: October 2006

Until recently, only three obligately aerobic bacteria (affiliated with the genus Pseudo‐monas) that can grow with nitrilotriacetate (NTA) as their only source of carbon, nitrogen, and energy have been isolated and studied in pure culture. By employing a different isolation strategy than was used previously, several nonpseudomonads were isolated in pure culture from both soil and wastewater that are able to utilize NTA under aerobic growth conditions. Additionally, a denitrifying bacterium was isolated from river sediment that is able to utilize NTA in the absence of oxygen. These isolates have been characterized with respect to their cell morphology and physiology. The data collected so far do not allow classification of both the gram‐negative and the gram‐positive strains isolated, and the taxonomic position of the isolates remains obscure. However, properties like C1 utilization, production of acetoïn, and nonmotility clearly indicate that the gram‐negative strains do not belong to the genus Pseudomonas. Information is presented on the regulation of NTA‐metabolizing enzymes in isolate TE 1 suggesting that these enzymes are inducible in this bacterium.
The effects of limiting nutrient to algal toxicity assessment: A theoretical approach
Authors: Chen Chung‐Yuan
Published: October 2006

The effects of limiting nutrient to algal toxicity tests are discussed. It has been shown, through theoretical derivation, that EC50 values will vary with changes of nutrient concentration even if the effects of limiting nutrient and limiting toxicant on algal growth are independent. The variation in EC50's is governed by the degree of correlation between two variables: the tolerance and the activation level. The proposed theory shows a potential application for making a comparison of results obtained from different laboratories or methods and for applying laboratory results to field conditions.
Microsomal‐activated cigarette smoke condensate reduces bacteriophage mu transposase gene expression in rec A+Escherichia coli
Authors: Kupelian Annie , Bilimoria Minoo H. , Dubow Michael S.
Published: October 2006

The effects of genotoxic agents on DNA structure, repair, and mutation—induction have shown many clear effects and mechanisms, yet their action on cellular transposons and insertion elements has been less well examined. We are interested in addressing the effect of environmental insults on the induction of DNA transposition of a cell's complement of mobile genetic elements. We have previously described a model system whereby we can measure the transposition potential of a cell by fusing bacteriophage Mu's (a plaque‐forming viral transposon) transposase (A gene) to that encoding β‐galactosidase (lac Z) and assaying for changes in β‐galactosidase expression after exposure of cells to toxic agents. We found that a known DNA‐damaging agent, γ‐rays, appeared to exert no discernible effect on Mu DNA transposition or transposase gene expression. In addition to monitoring the consequences of simple extrinsic agents, however, we were also curious to see how complex environmental mutagens influence DNA transposition and transposase gene expression.

To accomplish this, we studied Mu transposase gene expression after exposure of E. coli cells harboring the Mu A′‐′lac Z fusion plasmid pMD12 to six different cigarette smoke condensates (CSC). Upon exposure to CSC alone, no apparent pattern of changes in Mu transposase expression was observed in either rec A+ or rec A− strains. However, when the CSC were treated with an Aroclor 1254 activated liver microsomal fraction, there was a consistent dose‐dependent decrease in transposase expression in rec A+ E. coli, but not in an otherwise isogenic rec A− strain. This result is specific for Mu transposase expression as control strains, containing the lac Z gene under its own regulatory circuitry rather than that of the Mu transposase gene, did not exhibit a striking positive or negative effect on β‐galactosidase expression when exposed to CSC.
Evaluation of seven sediment toxicity tests and their relationships to stream parameters
Authors: Burton G. A.
Published: October 2006

A survey of sediment microbial activity and toxicity to Daphnia magna, Ceriodaphnia dubia, and Selenastrum capricornutum was conducted on two streams receiving numerous effluents in Ohio—the Little Scioto River and Dick's Creek. Microbial activity assays included alkaline phosphatase, dehydrogenase, β‐galactosidase, β‐glucosidase. Activity was compared to overlying water chemistry and revealed several statistically significant correlations. No macrofaunal assay toxicity was observed in Dick's Creek. Sediment toxicity was found at two stations in the Little Scioto River, and varied in degree and organism sensitivity with time of sampling. These results support earlier studies suggesting the need for multiple trophic‐level assays in aquatic ecosystem evaluations of toxicant impacts.
Bacterial growth in water
Authors: Adam Ofra , Kott Yehuda
Published: October 2006

Water sources often contain various micropollutants that will allow the regrowth of bacteria in the distribution system after treatment of the water.

The current methods used to evaluate this regrowth capability are often cumbersome and do not yield adequate answers to the question of these micropollutant levels.

In order to evaluate bacterial growth capability in a precise way, four sensitive turbidimeters, measuring turbidity at 12° forward scattering light and attached to a microcomputer, were used to continuously monitor bacterial growth rates in the water being studied. Standard plate counts at 20 and 37° C were simultaneously performed.

The results of the plate counts did not show whether the various treatment processes were effective. On the other hand, the growth curves plotted by the programmed turbidimeters showed distinct differences in the various water quality parameters.

Thus it was shown that ozone‐treated water enhanced bacterial growth, coagulation followed by filtration was not very effective, while a slow sand filter pilot plant yielded water with very little micropollutants and a very reduced bacterial regrowth capability.

This growth recording device can be used in a novel way to evaluate the bacterial regrowth capability of various waters and at various stages during water treatment.
Antibiotic and toxicant susceptibility profiles of clinical and environmental Klebsiella pneumoniae isolates
Authors: Seyfried P. L. , Desjardins R. M. , Alarcon A. E. , Kulendran N. , Sidarous M. , Harris E. , Bradbury W. C. , Young M.
Published: October 2006

Klebsiella pneumoniae strains isolated from different clinical and environmental sources were examined for resistance to antibiotics, pentachlorophenol, and heavy metals using intracellular ATP measurements. Resistance to kanamycin, neomycin, gentamicin, and tobramycin was noted for the hospital strain but not for the environmentally derived isolates. On the other hand, strains isolated from pulp and paper mill effluents and receiving waters exhibited a higher degree of pentachlorophenol and heavy metal resistance. Chromosomal restriction endonuclease analysis (REA) digests of three environmental strains produced patterns that were different and readily distinguishable. Plasmids were detectable in these same environmental isolates; two of the three carried a 70 × 106 Da plasmid that is thought to mediate both antibiotic and heavy metal resistance.
Copper toxicity in freshwater sediment and Aeromonas hydrophila cell suspensions measured using an O2 electrode
Authors: Flemming C. A. , Trevors J. T.
Published: October 2006

The effect of CuSO4 on O2 consumption in sediment samples and a pure culture of Aeromonas hydrophila were examined using an O2 electrode. Maximum inhibition of O2 consumption in sediment samples was 85% at Cu concentrations ranging from 400 to 500 μg/g sediment. In contrast, O2 consumption by A. hydrophila cell suspensions was inhibited 100% at Cu concentrations of 150 μg/mL in stream water and 250 μg/mL in sediment extract, respectively. Nonbiological (chemical) O2 consumption also occurred in sediment samples during the bioassay. This was demonstrated by respiration insensitive to KCN (metabolic inhibitor) and the observation that chemical O2 consumption occurred in autoclaved sediment samples. Caution should be taken when interpreting O2 consumption data in environmental samples as nonbiological reactions may interfere with the bioassay.