bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elevated levels of the mismatch repair protein PMS2 are associated with prostate cancer
Authors: Norris Alixanna M. , Woodruff R.D. , D'Agostino Ralph B. , Clodfelter Jill E. , Scarpinato Karin Drotschmann 
Published: October 2006

AbstractBackgroundDefects in mismatch repair (MMR) proteins have been identified in various types of cancer. However, an association with prostate cancer has been controversial. Defective MMR results in genome instability with detrimental consequences that significantly contribute to tumorigenesis. This study determined alterations in key MMR protein levels in prostate cancer with the goal to identify prognostic markers.MethodsProstatectomy samples were immunohistochemically stained and the relative presence or absence of key proteins MSH2, MLH1, and PMS2 determined. Cancer tissue of distinct grades was compared with the normal surrounding tissue. Microsatellite instability (MSI) in altered tissues was determined according to NCI guidelines.ResultsIn contrast to reports that associate a lack of individual MMR proteins with tumorigenesis, a significant increase in PMS2 levels was identified in PIN lesions and prostate cancer tissue. This elevation in PMS2 was independent of changes in levels in its heterodimeric partner, MLH1. Prostate tumors with elevated levels of PMS2 were genetically unstable, which was corrected by MLH1 co‐elevation.ConclusionsThis is the first documentation of detrimental consequences associated with the increase in a MMR protein in human cancer. This study recognizes PMS2 elevation as a prognostic marker in pre‐neoplastic and prostate cancer lesions. This result has significant implications for future diagnostic and treatment measures. Prostate © 2006 Wiley‐Liss, Inc.
Insights into protein structure and function from disorder–complexity space
Authors: Weathers Edward A. , Paulaitis Michael E. , Woolf Thomas B. , Hoh Jan H. 
Published: October 2006

AbstractIntrinsically disordered proteins have a wide variety of important functional roles. However, the relationship between sequence and function in these proteins is significantly different than that for well‐folded proteins. In a previous work, we showed that the propensity to be disordered can be recognized based on sequence composition alone. Here that analysis is furthered by examining the relationship of disorder propensity to sequence complexity, where the metrics for these two properties depend only on composition. The distributions of 40 amino acid peptides from both ordered and disordered proteins are graphed in this disorder–complexity space. An analysis of Swiss‐Prot shows that most peptides have high complexity and relatively low disorder. However, there are also an appreciable number of low complexity–high disorder peptides in the database. In contrast, there are no low complexity–low disorder peptides. A similar analysis for peptides in the PDB reveals a much narrower distribution, with few peptides of low complexity and high disorder. In this case, the bounds of the disorder–complexity distribution are well defined and might be used to evaluate the likelihood that a peptide can be crystallized with current methods. The disorder–complexity distributions of individual proteins and sets of proteins grouped by function are also examined. Among individual proteins, there is an enormous variety of distributions that in some cases can be rationalized with regard to function. Groups of functionally related proteins are found to have distributions that are similar within each group but show notable differences between groups. Finally, a pattern matching algorithm is used to search for proteins with particular disorder–complexity distributions. The results suggest that this approach might be used to identify relationships between otherwise dissimilar proteins. Proteins 2007. © 2006 Wiley‐Liss, Inc.
Thermoluminescence response and apparent anomalous fading factor of Durango fluorapatite as a function of the heating rate
Authors: Kitis G. , Polymeris G. S. , Pagonis V. , Tsirliganis N. C. 
Published: October 2006

AbstractThe anomalous fading (AF) of the Thermoluminescence (TL) signal has been observed in Durango apatite, and is believed to be caused by electrons transferred to the recombination sites via a tunnelling effect. The AF factor is a property unique for each glow‐peak of a glow‐curve and shows a remarkable stability, even when extreme experimental conditions are applied to this material. In the present work the AF is studied as a function of the rate at which the material is heated in order to obtain its TL. In this experimental study it is found that the TL response of Durango apatite is drastically increased as the rate of heating increases, contrary to what is expected from standard kinetic models of TL. An important consequence of this result is that, since the AF rate is monitored through the TL signal, the variations of TL as a function of the heating rate will be passed on to the evaluation of the AF rate. The result is an apparent decrease of the AF with an increasing heating rate, although the actual AF effect has no relation with the TL readout process. A possible explanation is proposed for the increase of the TL response and for the apparent decrease of the AF rate with the rate of heating. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Rapid online equilibration method to determine the D/H ratios of non‐exchangeable hydrogen in cellulose
Authors: Filot Marc S. , Leuenberger Markus , Pazdur Anna , Boettger Tatjana 
Published: October 2006

AbstractAn improved method for the determination of deuterium‐to‐hydrogen (D/H) ratios of non‐exchangeable hydrogen in cellulose is presented. The method is based on the equilibration reaction of the hydroxyl hydrogen of cellulose and water vapour of known isotopic composition. The equilibrated cellulose is pyrolysed and the total D/H ratio determined by subsequent online isotope ratio mass spectrometry (IRMS). With a mass balance system the D/H ratio of non‐exchangeable hydrogen is recalculated after an empirical calibration has been performed, yielding a mean exchangeability of 0.239 and an equilibrium fractionation factor of 1.082 between the hydroxyl hydrogen of cellulose and water hydrogen at 110°C. Equilibration takes 10 min per sample. Results obtained by this online equilibration method agree very well with values obtained by the nitration technique (R2 = 0.941). The uncertainty of the equilibration method is ±4‰ resulting from a single standard deviation of ±2.8‰ for the equilibration determined by standard cellulose and 2.8‰ from the variable exchangeability of the hydroxyl hydrogen in cellulose due to crystalline areas. The latter uncertainty may be lowered by minimising the crystallinity of the cellulose. Advantages of this new technique are (i) the considerably reduced sample amount required (as low as 0.2 mg, ideally 0.5 mg compared with 20 mg for the conventional nitration technique); (ii) an approximately 100‐fold reduced process time; and (iii) no need for the hazardous chemicals used in the nitration technique. Copyright © 2006 John Wiley & Sons, Ltd.
High‐precision isotopic analysis of palmitoylcarnitine by liquid chromatography/electrospray ionization ion‐trap tandem mass spectrometry
Authors: Guo ZengKui , Yarasheski Kevin , Jensen Michael D. 
Published: October 2006

AbstractSingle quadrupole gas chromatography/mass spectrometry (GC/MS) has been widely used for isotopic analysis in metabolic investigations using stable isotopes as tracers. However, its inherent shortcomings prohibit it from broader use, including low isotopic precision and the need for chemical derivatization of the analyte. In order to improve isotopic detection power, liquid chromatography/electrospray ionization ion‐trap tandem mass spectrometry (LC/ESI‐itMS2) has been evaluated for its isotopic precision and chemical sensitivity for the analysis of [13C]palmitoylcarnitine. Over the enrichment range of 0.4–10 MPE (molar % excess), the isotopic response of LC/ESI‐itMS2 to [13C]palmitoylcarnitine was linear (r = 1.00) and the average isotopic precision (standard deviation, SD) was 0.11 MPE with an average coefficient of variation (CV) of 5.6%. At the lower end of isotopic enrichments (0.4–0.9 MPE), the isotopic precision was 0.05 MPE (CV = 8%). Routine analysis of rat skeletal muscle [13C4]palmitoylcarnitine demonstrated an isotopic precision of 0.03 MPE for gastrocnemius (n = 16) and of 0.02 MPE for tibialis anterior (n = 16). The high precision enabled the detection of a small (0.08 MPE) but significant (P = 0.01) difference in [13C4]palmitoylcarnitine enrichments between the two muscles, 0.51 MPE (CV = 5.8%) and 0.43 MPE (CV = 4.6%), respectively. Therefore, the system demonstrated an isotopic lower detection limit (LDL) of ≤0.1 MPE (2 × SD) that has been impossible previously with other organic mass spectrometry instruments. LC/ESI‐itMS2 systems have the potential to advance metabolic investigations using stable isotopes to a new level by significantly increasing the isotopic solving power. Copyright © 2006 John Wiley & Sons, Ltd.
Prophage Mu induction as a tool to analyze mobile genetic element responses to external agents
Authors: Dubow Michael S. , Shinder Gayle 
Published: October 2006

AbstractMobile genetic elements have been found in the genomes of both procaryotic and eucaryotic organisms. Their unique capacity to move (or transpose) to new chromosomal locations has been critical to their persistence and their ability to affect gene structure and expression. It is conceivable that many physical and chemical agents may induce non‐specific DNA transpositions which can result in genomic rearrangements and mutations. We have derived a simple procedure to detect the induction of DNA transposition using bacteriophage Mu, a temperate coliphage whose 37 kilobase linear double‐stranded DNA genome behaves as a transposable element during lytic growth and lysogeny. Our assay measures the ability of a chemical to enhance or inhibit the induction of Mu DNA transposition and lytic growth. We have examined a wide variety of mutagens, carcinogens and common chemical compounds and found that most of these agents had little effect on prophage Mu induction and lytic growth at all doses tested. However, many DNA‐damaging agents showed a dose‐dependent decrease in both the number of plaque‐forming units and the number of colony‐forming units. We did find that the frequency of prophage Mu induction can be stimulated by certain amino acid analogues, notably azetidine 2‐carboxylic acid, but not by others. These results indicate that the response of mobile genetic elements to external agents is not a simple one, and may reflect the necessary presence of an element and cellular regulatory pathway to control these endogenous mutators.
“Basic” respiration rate as a tool for prediction of pesticide persistence in soil
Authors: Torstensson Lennart , Stenström John 
Published: October 2006

AbstractA method for determination of the “basic” respiration rate of soils, as the rate of O2‐consumption, has been developed. It includes standardization of both the handling of samples before determination and of the temperature and the water content at which the determination is performed. The respiration rate determined in this way varies less than normally occurs when samples of a soil are taken over a period of time. Neither the handling at sampling nor the variation in time before determination influences the result. Comparisons between a soil's respiration rate and its ability to decompose a pesticide are more easily made if the decomposition data can be expressed in mathematical form and thereby linearized. This has been done for linuron and glyphosate by plotting the decomposition data according to the formulac=co–k√tt.Good correlation between the rate of respiration and the rate of decomposition (k‐value) was found for linuron and glyphosate in laboratory experiments and also for glyphosate in field experiments.
Toxicity analysis of leachates from hazardous wastes via microtox and daphnia magna
Authors: Calleja A. , Baldasano J. M. , Mulet A. 
Published: October 2006

AbstractOne of the most common ways of surface and ground water contamination from hazardous wastes is through its leachates. Toxicity is a meaningful parameter allowing an integrated evaluation of the potential danger of leachates. Two bioassays were considered for measuring toxicity: Microtox and Daphnia magna. The toxicity was measured on leachates obtained, using different leaching procedures, from wastes of a pesticide manufacturing industry and sludge from electroplating wastewater. Twenty‐two tests were carried out, measuring IC50 for D. magna and EC50 for Microtox. Both bioassays were compared using three toxicity criteria. The first criterium is classification on toxic/non‐toxic at 25 and 50% leachate concentration. The second criterium is classification on percent ranks, and the third on log ranks. Considering these criteria, the agreement between both bioassays is within a 75–85%. It is shown that both, Microtox and D. magna assays could be used as toxicity indicators for the wastes considered. The sensitivity of the bioassays is different depending on leachate composition. In all samples, the leachate concentration of chemicals was measured.
A simple microplate algal assay technique for aquatic toxicity assessment
Authors: Blaise C. , Legault R. , Bermingham N. , Van Coillie R. , Vasseur P. 
Published: October 2006

AbstractA simple, miniaturized algal assay procedure using microplates has been developed to assess aquatic toxicity with the green alga, Selenastrum capricornutum. Cell count‐generated EC50 data comparisons with the classic assay using flasks have indicated good agreement between the two methods following toxic assessment of various wastewater samples and metal solutions. Parametric comparisons (ATP us cell counts) with the microplate method show equally good correlation. The technique is highly versatile in conducting basic algal bioassays for varying times (4‐hour, 4‐day, 8‐day EC50's) and with differing parameters, depending on set objectives. Other interesting features of the microplate technique include handling rapidity, economy, space‐saving convenience, and automation potential.
Environmental effects testing with quantitative microbial analysis: Chemical signatures correlated within situbiofilm analysis by FT/IR
Authors: White David C. 
Published: October 2006

AbstractChemical measures for the biomass, community structure, nutritional status, and metabolic activities of the microbiota have shown a remarkable responsiveness to changes in the bulk fluid physical and chemical properties, the chemistry, biodegradability, and microtopology of the surfaces, as well as biological factors such as predation. Chemical analysis of the microbiota (bacteria, algae, fungi, protozoa, and micrometazoa with their extracellular products <0.5mm in diameter) does not require quantitative release of the organisms from surfaces or that the organisms are able to form colonies in subcultures. The sensitivity of the microbiota to changes in their habitat suggests that these chemical measures could provide a quantitative method for environmental effects testing. Changes in the marine benthic microbiota exposure to xenobiotics at the ug/l level or oil and gas well‐drilling fluids demonstrate this sensitivity. These analyses do not destroy the vital interactions within microcolonies of mixed physiological types that characterize many environments. The chemical measures are destructive. Non‐destructive analysis of biofilms of areas in the size range of microcolonies by Fourier transforming infrared spectrometry may ultimately provide the most effective method for environmental effects testing.
The effect of selected biocides on sulfate‐reducing bacteria
Authors: L‐zanfaly H. T. E , Kassim E. A. , Hassan H. M. 
Published: October 2006

AbstractGrowth of 26 strains of sulfate‐reducing bacteria isolated from the environment was inhibited by two cationic surfactants, namely, Hyamine 2389 and Lutensit K‐LC at concentrations of 166 mg/1 or less. Hyamine 1622 (cationic) inhibited 21 strains at a concentration of 100 mg/1. Two strains were resistant to 100 mg/1 of Chloramine T, but 4 strains were resistant to 60 mg/1. Hydrogen peroxide at the concentration of 583 mg/1 was able to prevent the growth of 17 strains.Time‐kill tests indicated that the majority of the strains were sensitive to all tested biocides during the first few minutes of exposure which extended to about one hour at lower concentrations.Lowering the temperature during exposure of bacteria did not exert any substantial effect on the biocidal efficiency of the tested chemicals. Higher concentrations of the biocides may require the lowering or raising of the pH and in the presence of organic matter.
Evaluation of toxicity test procedure for screening treatability potential of waste in soil
Authors: Matthews J. E. , Hastings L. 
Published: October 2006

AbstractA toxicity procedure has been developed and proposed for use in establishing acceptable initial loading rates and detoxification potentials for hazardous industrial waste when combined with soil. The procedure involves conducting toxicity screening and toxicity reduction experiments using selected waste‐soil combinations. These experiments employ a bacterial bioluminescence assay (MicrotoxTM) to determine acute toxicity of organic contaminants contained in the water soluble fraction (WSF) of waste‐soil mixtures. Toxicity screening test results are used to establish a range of loading rates acceptable for use in subsequent waste‐soil treatability studies. Toxicity reduction experimental results are used to determine soil detoxification potentials over time for soluble toxic organics contained in the waste‐soil loading combination selected. A major factor in determining acceptability of any test procedure is whether or not different investigators can achieve reproducible and comparable results. This paper describes the proposed procedure and reports results from toxicity experiments conducted concurrently by two laboratories using aliquots from the same soil and waste samples. Comparability of results was reported to be a function of the similarity of waste sample aliquots used in the toxicity experiments. Toxicity screening results for uniform technical grade creosote aliquots were highly comparable between the two laboratories, while results for highly variable creosote wood preserving waste (WPC) aliquots were much less comparable. Toxicity reduction experimental results for the WPC waste also indicated significant variation between laboratories for initial (Day 0) samples; however, the same patterns of detoxification over time were observed by each laboratory with toxicity results at the end of the experimental period (Day 42) being similar. Although the research described in this article has been funded wholly or in part by the U.S. Environmental Protection Agency, it has not been subjected to the agency's peer and administrative review and therefore may not necessarily reflect the views of the agency and no official endorsement should be inferred.
The action of pesticides on microorganisms. I. parathion
Authors: Rosas Susana B. , De Storani Maria M. Carranza 
Published: October 2006

AbstractPrevious experiments indicate that parathion, DDT, aldrin, and dieldrin induce changes in fatty acid and phospholipid composition in Escherichia coli. The effect of parathion on the growth and viability of E. coli, P. aeruginosa and R. meliloti was studied. When the pesticide was present at a concentration of 8.6 × 10−6M, the following effects were observed: P. aeruginosa growth was not affected, E. coli was slightly inhibited and R. meliloti was affected adversely in the incubation mixture. We also examined the effects on the cell membrane components such as phospholipids and proteins; both quantitative and qualitative changes were observed. The results varied according to the microorganism utilized. Our data revealed alterations in the phospholipids that may be an important adaptative response of microorganism to growth in the presence of the pesticides.
The development of whole cell biosensors for on‐line screening of herbicide pollution of surface waters
Authors: Rawson David M. , Willmer Allison J. , Cardosi Marco F. 
Published: October 2006

AbstractThe use of mediator assisted amperometric whole‐cell biosensors, monitoring microbial photosynthetic electron transfer, to screen for herbicides in intake protection by the water industry is described. Cells harvested from axenic cultures are loaded onto bacteriological filters and held against a working carbon electrode polarised against the silver chloride reference. Redox mediators are reduced by the microorganisms and then reoxidised at the working electrode resulting in a flow of current. For on‐line applications the sensors are controlled by a programmable electrochemical analyser (Artek) and housed in specially designed perspex flow cells which incorporate light emitting diodes (LEDs) for photosynthetic stimulation. A range of cyanobacteria and algae have been tested, but biosensors incorporating unicellular cyanobacteria have proven the most successful. Results obtained using the cyanobacterium Synechococcus show detection levels of less than 200 ppb with response times of less than ten minutes for selected herbicides. Sensor stability in the absence of pollutant poisoning has been found to be greatly influenced by the choice of mediator. Membrane penetrating mediators such as ‐benzoquinone reduce sensor life to about 24 hours, while a sensor life of up to six days has been achieved with ferricyanide.
Toxicity and accumulation of cadmium with respect to algae and cyanobacteria: A review
Authors: Vymazal Jan 
Published: October 2006

AbstractCadmium is always found in association with zinc. However, zinc is an essential micronutrient in living cells, whereas cadmium has no known useful biological function. In fact, cadmium is ranked among the most hazardous trace elements in the environment and is highly toxic to all components of aquatic communities. Cadmium in soils seems tightly held and is not readily removed by leaching, and consequently, cadmium in freshwaters is mostly connected with human activities. The concentration of Cd in natural waters is usually less than 1 μg. L−1 but the values vary greatly among localities; the highest concentrations of cadmium have been observed in areas with acid mine drainage. The important mechanism of toxic action of Cd on algae and cyanobacteria is thought to be the „poisoning”︁ of enzymes, but many other toxic actions are known. A variety of environmental factors are known to modify the toxicity of cadmium. It is very difficult to allow for all of these factors simultaneously to predict the effect that a given amount of a metal will have on a given algal population. Uptake of Cd and other heavy metals to produce an internal concentration than in the external environment appears widespread in algae and cyanobacteria.
Assessment of methods for evaluating the treatability of sewage and the effects of industrial discharges
Authors: Robinsons R. J. 
Published: October 2006

AbstractFive tests, based on methods currently in use for measuring the inhibition of rates of respiration, nitrification, and growth of bacteria, are evaluated for use as screening tests for assessing the treatability of settled sewage and toxicity of industrial effluent. A treatability factor is derived for each test for a series of settled sewages and a toxicity factor for industrial effluents by comparison with control standards. The Microtox test gives greater sensitivity, repeatability, and precision, but possible problems in the interpretation of the results warrant further comparison with the remaining tests, all of which show reasonable promise.