J Chromatogr A, 1999 Jul 23, 849(2), 371 - 80 Improvement in the Iatroscan thin-layer chromatographic-flame ionisation detection analysis of marine lipids . Separation and quantitation of monoacylglycerols and diacylglycerols in standards and natural samples; Striby L et al.; Mono- and diacylglycerols are important intermediates in glycerolipid biodegradation and intracellular signalling pathways . A method for mass determination of these lipid classes in marine particles was developed using the Iatroscan, which combines thin layer chromatography (TLC) and flame ionisation detection (FID) techniques . We improved existing protocols by adding two elution steps: hexane-diethyl-ether-formic acid (70:30:0.2, v/v/v) after triacylglycerol and free fatty acid scan, and acetone 100% followed by chloroform-acetone-formic acid (99:1:0.2, v/v/v) after 1,2 diacylglycerols . Diacylglycerol isomers 1,2 and 1,3 were separated from each other, as well as from free sterols in standards and marine lipids from sediment trap particles . Monoacylglycerols were separated from pigments and galactosyl-lipids in the same trap samples and in a rich pigment phytoplankton extract of Dunaliella viridis . Quantitation of each class in samples was performed after calibration with 0.5 to 2 micrograms of standards . As many as 17 lipid classes can be identified and quantified in samples using this proposed six-step development. Can J Microbiol, 1999 Jun, 45(6), 520 - 9 Cross-induction of pyrene and phenanthrene in a Mycobacterium sp . isolated from polycyclic aromatic hydrocarbon contaminated river sediments; Molina M et al.; A polycyclic aromatic hydrocarbon (PAH)-degrading culture enriched from contaminated river sediments and a Mycobacterium sp . isolated from the enrichment were tested to investigate the possible synergistic and antagonistic interactions affecting the degradation of pyrene in the presence of low molecular weight PAHs . The Mycobacterium sp . was able to mineralize 63% of the added pyrene when it was present as a sole source of carbon and energy . When the enrichment culture and the isolated bacterium were exposed to phenanthrene, de novo protein synthesis was not required for the rapid mineralization of pyrene, which reached 52% in chloramphenicol-treated cultures and 44% in the absence of the protein inhibitor . In the presence of chloramphenicol, < 1% of the added pyrene was mineralized by the mixed culture after exposure to anthracene and naphthalene . These compounds did not inhibit pyrene utilization when present at the same time as pyrene . Concurrent mineralization of pyrene and phenanthrene after exposure to either compound was observed . Cross-acclimation between ring classes of PAHs may be a potentially important interaction influencing the biodegradation of aromatic compounds in contaminated environments. Cytometry, 1999 Sep 1, 37(1), 14 - 20 Correlating cell cycle with metabolism in single cells: combination of image and metabolic cytometry; Krylov SN et al.; BACKGROUND: We coin two terms: First, chemical cytometry describes the use of high-sensitivity chemical analysis techniques to study single cells . Second, metabolic cytometry is a form of chemical cytometry that monitors a cascade of biosynthetic and biodegradation products generated in a single cell . In this paper, we describe the combination of metabolic cytometry with image cytometry to correlate oligosaccharide metabolic activity with cell cycle . We use this technique to measure DNA ploidy, the uptake of a fluorescent disaccharide, and the amount of metabolic products in a single cell . METHODS: A colon adenocarcinoma cell line (HT29) was incubated with a fluorescent disaccharide, which was taken up by the cells and converted into a series of biosynthetic and biodegradation products . The cells were also treated with YOYO-3 and Hoechst 33342 . The YOYO-3 signal was used as a live-dead assay, while the Hoechst 33342 signal was used to estimate the ploidy of live cells by fluorescence image cytometry . After ploidy analysis, a cell was injected into a fused-silica capillary, where the cell was lysed . Fluorescent metabolic products were then separated by capillary electrophoresis and detected by laser-induced fluorescence . RESULTS: Substrate uptake measured with metabolic cytometry gave rise to results similar to those measured by use of laser scanning confocal microscopy . The DNA ploidy histogram obtained with our simple image cytometry technique was similar to that obtained using flow cytometry . The cells in the G(1) phase did not show any biosynthetic activity in respect to the substrate . Several groups of cells with unique biosynthetic patterns were distinguished within G(2)/M cells . CONCLUSIONS: This is the first report that combined metabolic and image cytometry to correlate formation of metabolic products with cell cycle . A complete enzymatic cascade is monitored on a cell-by-cell basis and correlated with cell cycle . J Biomed Mater Res, 1999 Nov, 47(2), 270 - 7 Characterization and biocompatibility of epoxy-crosslinked dermal sheep collagens; van Wachem PB et al.; Dermal sheep collagen (DSC), which was crosslinked with 1, 4-butanediol diglycidyl ether (BD) by using four different conditions, was characterized and its biocompatibility was evaluated after subcutaneous implantation in rats . Crosslinking at pH 9.0 (BD90) or with successive epoxy and carbodiimide steps (BD45EN) resulted in a large increase in the shrinkage temperature (T(s)) in combination with a clear reduction in amines . Crosslinking at pH 4.5 (BD45) increased the T(s) of the material but hardly reduced the number of amines . Acylation (BD45HAc) showed the largest reduction in amines in combination with the lowest T(s) . An evaluation of the implants showed that BD45, BD90, and BD45EN were biocompatible . A high influx of polymorphonuclear cells and macrophages was observed for BD45HAc, but this subsided at day 5 . At week 6 the BD45 had completely degraded and BD45HAc was remarkably reduced in size, while BD45EN showed a clear size reduction of the outer DSC bundles; BD90 showed none of these features . This agreed with the observed degree of macrophage accumulation and giant cell formation . None of the materials calcified . For the purpose of soft tissue replacement, BD90 was defined as the material of choice because it combined biocompatibility, low cellular ingrowth, low biodegradation, and the absence of calcification with fibroblast ingrowth and new collagen formation . Can J Microbiol, 1999 May, 45(5), 377 - 88 Microbial mineralization of diisopropanolamine; Gieg LM et al.; Diisopropanolamine (DIPA) is a "sweetening agent" used to remove hydrogen sulfide from sour natural gas, and it is a contaminant at some sour gas treatment facilities in western Canada . To investigate the biodegradation of this alkanolamine, 14C-DIPA was used in anaerobic and aerobic mineralization studies . Between 3 and 78% of the radioactivity from this compound was released as 14CO2 in sediment-enrichment cultures incubated under nitrate-reducing conditions . Similarly, 12-78% of the label was converted to 14CO2 in sediment-enrichment cultures incubated under Mn(IV)-reducing conditions . These activities were observed at 8 degrees C, a typical groundwater temperature in western Canada, and at 28 degrees C . In contrast, DIPA-degrading activity was difficult to sustain under Fe(III)-reducing conditions, and < 25% of the radioactive label from 14C-DIPA was liberated as 14CO2 . Two mixed cultures and two isolates (both irregular, non-sporeforming, Gram-positive rods) were used to assess aerobic mineralization of 14C-DIPA . The aerobic mixed cultures released 73 and 79% of the radioactive label as 14CO2, whereas the pure cultures liberated only 39 and 47% as 14CO2 . Between one-third and one-half of the nitrogen from DIPA was found as ammonium-N in aerobic batch cultures . These results clearly demonstrate that DIPA is mineralized under a variety of incubation conditions. Can J Microbiol, 1999 May, 45(5), 360 - 8 Biodegradation of benzothiophene sulfones by a filamentous bacterium; Bressler DC et al.; Previous studies showed that benzothiophene and 3- and 5-methylbenzothiophenes are oxidized by some bacteria to yield their corresponding sulfones, which were not subsequently degraded . In this study, a filamentous bacterium was isolated, which grew on each of these three sulfones as its sole carbon, sulfur, and energy source . Based on 16S rRNA gene sequencing and scanning electron microscopy, the isolate was found to belong to the genus Pseudonocardia and assigned the strain designation DB1 . Benzothiophene sulfone and 3-methylbenzothiophene sulfone were more readily biodegraded than 5-methylbenzothiophene sulfone, and growth on these three compounds resulted in the release of 57, 62, and 28% of the substrate carbon as CO2, respectively . The thiophene ring was also cleaved, and between 44 and 88% of the sulfur from the consumed substrate was found as sulfate and (or) sulfite . Strain DB1 grew on benzoate, dibenzothiophene sulfone, and hexadecanoic acid, but it could not grow on benzofuran, dibenzothiophene, dibenzothiophene sulfoxide, hexadecane, indole, naphthalene, phenol, 2-sulfobenzoic acid, sulfolane, benzothiophene, or 3- or 5-methylbenzothiophenes . In addition, it did not oxidize the latter three compounds to their sulfones. Microb Ecol, 1999 Aug, 38(2), 114 - 125 Occurrence of Two Resin Acid-Degrading Bacteria and a Gene Encoding Resin Acid Biodegradation in Pulp and Paper Mill Effluent Biotreatment Systems Assayed by PCR; Yu Z et al.; > Abstract We examined the distribution of two dehydroabietic acid-degrading bacteria, Pseudomonas abietaniphila BKME-9 and Zoogloea resiniphila DhA-35, in biotreatment systems for pulp and paper mill effluents (PPMEs) using PCR assays . These two bacteria were first isolated from two PPME biotreatment systems and can degrade both dehydroabietic acid (DhA) and other abietane resin acids . We also examined the distribution of a catabolic gene, ditA1, encoding the alpha subunit of an aromatic ring-hydroxylating dioxygenase involved in DhA degradation by BKME-9 . PCR primers specific for the 16S rDNA of BKME-9 and of DhA-35 and specific for ditA1 were used . Among 3 laboratory- and 17 full-scale PPME biotreatment systems, 10 contained phylotype BKME-9, 3 contained phylotype DhA-35, and 11 contained ditA1, indicating the wider distribution of phylotype BKME-9 than of phylotype DhA-35 . Both phylotype BKME-9 and ditA1 were detected in the biotreatment system from which BKME-9 was originally isolated in 1994, suggesting the persistance of BKME-9 in that biotreatment system . The detection limit of the PCR assay was one cell per PCR reaction, which corresponds to one BKME-9 cell per 6 x 10(7) total sludge bacteria . A competitive PCR assay indicated that ditA1 ranged from 51 to 250 copies/mg of dry biomass . BKME-9 appears to contribute to the biodegration of resin acids in some PPME biotreatment systems . Using degenerate PCR primers and touchdown PCR, we obtained from our DhA-degrading strain collection six DNA sequences putatively homologous to that of ditA1 . Cluster analysis of these DNA sequences suggests that ditA1 encodes a representative of a novel class of dioxygenase enzymes.http://link.springer-ny.com/link/service/journals/00248/bibs/38n2p114.html Fungal Genet Biol, 1999 Jul-Aug, 27(2-3), 175 - 85 Biodegradation of lignin by white rot fungi; Leonowicz A et al.; A review is presented related to the biochemistry of lignocellulose transformation . The biodegradation of wood constituents is currently understood as a multienzymatic process with the mediation of small molecules; therefore, this review will focus on the roles of these small molecular compounds and radicals working in concert with enzymes . Wood rotting basidiomycetous fungi penetrate wood and lead to more easily metabolized, carbohydrate constituents of the complex . Having a versatile machinery of enzymes, the white rot fungi are able to attack directly the "lignin barrier." They also use a multienzyme system including so-called "feed back" type enzymes, allowing for simultaneous transformation of both lignin and cellulose . These enzymes may function separately or cooperatively . J Dent Res, 1999 Aug, 78(8), 1459 - 68 Biodegradation of commercial dental composites by cholesterol esterase; Santerre JP et al.; The research literature suggests that current dental polymeric composites are not chemically inert at the material/biological interface . Several studies have investigated the process of "biodegradation" on dental composites in the presence of enzymes, by monitoring changes in weight loss and surface hardness properties . However, it is hypothesized that these methods can provide an erroneous measure of biochemically induced degradation, since they are less sensitive to molecular events and lack the ability to provide chemical information . Knowledge of the latter is important because it relates to the biological significance of biodegradation, i.e., the identification and quantification of released compounds that may be capable of influencing cell, bacteria, or enzyme function . It was the objective of this study to compare three methods (weight loss, surface micro-hardness, and liquid chromatography combined with mass spectrometry) for their ability to measure the effect of enzyme-induced biodegradation on three commercial composite resin materials . The enzyme was cholesterol esterase, and the composites were Silux Plus XL, Z100 A2 (3M), and TPH XL (L.D . Caulk) . Biodegradation was readily detected by liquid chromatography, and its sensitivity was shown to be substantially greater than that of weight loss or surface hardness measurements, although surface hardness measurements did show some agreement with liquid chromatography data . The data also indicated that the levels and distribution of released degradation products can vary substantially from one product to the next, and that this merits further investigation if the potential impact of different commercial restorative materials on cell and bacteria function is to be assessed. Biomed Mater Eng, 1999, 9(1), 49 - 59 Preparation and characterization of Japanese encephalitis virus vaccine loaded poly(L-lactide-co-glycolide) microspheres for oral immunization; Khang G et al.; Japanese encephalitis virus (JEV) vaccine loaded biodegradable poly(L-lactide-co-glycolide) (PLGA) microspheres (MSs) were prepared by W/O/W solvent evaporation method to study the possibility for oral vaccination . The influence of several preparation parameters as stirring rate, types and concentration of emulsifier, PLGA concentration, etc . has been observed on size, size distribution and biodegradation . The mean MSs size decreased when the agitation speed and the concentration of emulsifier were increased, and when the PLGA concentration was decreased . The surface morphology of porous and nonporous JEV vaccine loaded PLGA MSs was prepared from polyvinylalcohol and sodium dodecyl sulfate as used emulsifiers, respectively . From the assay of lactic acid and scanning electron microscope observation, it can be suggested that the rate of biodegradation of nonporous MSs was slower than that of porous surface morphology due to lower the surface area . Mechanisms of the formation of porous and nonporous surface by different types of emulsifier, and the biodegradation of MSs have been proposed . Also, the size and size distribution of JEV vaccine loaded PLGA MSs were discussed to apply oral vaccination through the Peyer's patches across the gastrointestinal tract. FEMS Microbiol Lett, 1999 Jul 15, 176(2), 477 - 82 Metabolism of phenylbenzoate by Pseudomonas sp . strain TR3; Reich T et al.; A bacterial isolate, tentatively identified as Pseudomonas sp . strain TR3, was found to utilize the diaryl ester phenylbenzoate as sole source of carbon and energy . This strain has the ability to productively degrade phenylbenzoate and some substituted derivatives by a catabolic sequence which was characterized biochemically . The biodegradation of phenylbenzoate is thus initiated by an inducible esterase, effectively hydrolyzing the diaryl esters to produce stoichiometric amounts of two monoaromatic metabolites, identified as benzoate and phenol in the case of phenylbenzoate . The diaryl ester p-tolylbenzoate was hydrolyzed to yield benzoate and 4-methylphenol while 4-chlorophenylbenzoate gave rise to the production of benzoate and 4-chlorophenol . These monoaromatic catabolites were further degraded via the oxoadipate pathway. J Biomater Sci Polym Ed, 1999, 10(7), 729 - 49 Commercial polyurethanes: the potential influence of auxiliary chemicals on the biodegradation process; Vermette P et al.; This investigation elucidates some aspects of auxiliary chemicals on the biodegradation of two commercial polyurethanes (Pellethane and Corethane) . The materials were incubated for 28 days with cholesterol esterase and/or with phosphatidylcholine . Extraction studies were carried out on the two materials, using different solvents, chosen on the basis of solvent polarity . FT-IR spectra for the extracted materials indicated the presence of poly(methylene)n oxide moities, silicone oil, bis-ethylene-stearamide, aromatic moities, and alkyd-urea compounds in Pellethane . Corethane materials were shown to contain some fatty acids, hydrocarbon waxes, ester-based species, and chlorinated compounds . Analysis of incubation solutions by high performance liquid chromatography failed to isolate methylene dianiline (MDA) or any of its derivatives from the various polymer incubation solutions . However, a methanol extract of Corethane samples that were incubated for 28 days in cholesterol esterase did show the presence of MDA . The absence of MDA in the Pellethane methanol extracted samples may reflect the differences in surface additives found for this material versus the Corethane . FT-IR/ATR analysis of polymer surfaces exposed to cholesterol esterase/phospholipids mixture showed that there was an increase in the uptake of phospholipids over samples that were incubated in phospholipid dispersion alone . The results of this study show that some of the auxiliary chemicals found in commercial polyurethanes may hinder the specific release of hydrolytic degradation products and delay polymer degradation . However, it should be recognized that the surface layer containing these compounds is susceptible to change following the interaction between the polyurethane-based devices and elements of the host environment (i.e . lipids, enzymes, etc.) . Hence, recognition and identification of these changes will ultimately be important in assessing a commercial polymer's blood compatibility characteristics. J Biomater Sci Polym Ed, 1999, 10(7), 699 - 713 The biodegradation of poly(urethane)s by the esterolytic activity of serine proteases and oxidative enzyme systems; Labow RS et al.; Biodegradation of poly(urethane)s (PU)s using single enzymes in vitro was assessed by measuring radiolabel release from model poly(ester-urea-urethane) (PESU) and poly(ether-urea-urethane) (PETU) materials synthesized with 14C-labelled monomers . Cholesterol esterase (CE), an enzyme found in monocyte-derived macrophages (MDM), has been reported to cause a significant level of radiolabel release from both of these PUs . Previous work has shown that CE activity could be inhibited by the serine protease/esterase inhibitor, phenylmethylsulfonyl fluoride . Since many serine proteases are present in circulating blood and can be released by cells other than MDM, this study investigated the ability of serine proteases relative to that of CE to cause the degradation of PUs . In addition, the possible role of several oxidative enzymes in the breakdown of PUs was investigated . Proteinase K, chymotrypsin and thrombin, when incubated with PESU, coated on glass slips, caused significant radiolabel release, with proteinase K giving the highest values . However, the highest radiolabel release which proteinase K could elicit was ten times less than CE . Thrombin and then chymotrypsin were progressively worse in their biodegradative activity . Only CE, and not the serine proteases, could elicit a detectable radiolabel release from PETU . Although the release of reactive oxygen species and molecular oxygen occur around an implanted biomaterial, several oxidative systems (peroxidase, xanthine oxidase, catalase), known to produce one or more of these molecular species, were unable to induce radiolabel release from these PUs . The process of biodegradation as assessed by radiolabel release appears to be a specific hydrolytic process, while the role of oxidative enzymes remains less clear. Biodegradation, 1999 Feb, 10(1), 43 - 50 Effect of nitrogen and phosphorus addition on phenanthrene biodegradation in four soils; Johnson CR et al.; Phenanthrene mineralization rates were found to vary widely among four soils; differences in soil nutrient levels was one hypothesis to explain this variation . To test this hypothesis, phenanthrene mineralization rates were measured in these soils with, and without, added nitrogen and phosphorus . Mineralization rates either remained unchanged or were depressed by the addition of nitrogen and phosphorus . Phenanthrene degradation rates remained unchanged in the soil which had the highest indigenous levels of nitrogen and phosphorus and which showed the largest increase in phosphorus levels after nutrients were added . The soils in which degradation rates were depressed had lower initial phosphorus concentrations and showed much smaller or no measurable increase in phosphorus levels after nutrients were added to the soils . To understand the response of phenanthrene degradation rates to added nitrogen and phosphorus, it may be necessary to consider the bioavailability of added nutrients and nutrient induced changes in microbial metabolism and ecology. Biodegradation, 1999 Feb, 10(1), 1 - 13 Biodegradation of aromatic compounds and TCE by a filamentous bacteria-dominated consortium; Bielefeldt AR et al.; The Michaelis-Menten biodegradation kinetics (k and Ks) of aromatic compounds and trichloroethene (TCE) by an aerobic enrichment culture grown on phenol and dominated by a unique filamentous bacterium were measured . The average k and Ks values for phenol, benzene (B), toluene (T), ethylbenzene (E), o-xylene (oX), p-xylene (pX), naphthalene and TCE in g per g VSS-d and mg L-1 were 5.72 and 0.34, 1.20 and 0.51, 2.09 and 0.47, 0.77 and 0.23, 0.61 and 0.16, 0.73 and 0.23, 0.17 and 0.18, and 0.16 and 0.18, respectively . Significant variability in these measured kinetics was noted between tests conducted over the 5-month period during which the fed-batch culture with a 5-day solids retention time was maintained; the coefficient of variation of the k and Ks values ranged from 11-43% and 4-50%, respectively . This variation was significantly greater than the method measurement error on a given date . Degradation of BTEoXpX mixtures could be described by a basic competitive inhibition model . Batch tests during which the culture was fed individual BTEX compounds showed the culture grew poorly on the xylenes and had poor subsequent xylene degradation rates . This work indicates the potential to simultaneously treat a mixture of volatile organic compounds using this consortium, and the ability to predict the mixture biodegradation rates on the basis of the individual compound biodegradation kinetics. New Microbiol, 1999 Jul, 22(3), 257 - 67 Effect of novel biosurfactants on biodegradation of polychlorinated biphenyls by pure and mixed bacterial cultures; Golyshin PM et al.; A study was conducted to determine the potential positive effect of novel biosurfactants on the enhancement of Aroclor 1248 metabolization in both in vitro and in situ experiments . Among two lipopeptides tested the highest activity was found in experiments with a hydrolytically opened form of lichenysin A . Lichenysin A itself did not enhance the degradation activity of chosen microorganism-degraders and in most cases inhibited their PCB mineralization rates . Glucolipid surfactant from marine bacterium Alcanivorax borkumensis showed in several tests a strong enhancing effect on microbial metabolization of Aroclor 1248 congeners . Biosurfactants appeared to act very specifically, i.e . depending on strain and concentration used . Experiments set up with soil samples did not give a clear answer whether bioemulsifiers applied at low concentration could sufficiently increase the rates of biodegradation in situ . Only A . borkumiensis glucose lipid caused the most marked enhancement of Aroclor 1248 metabolization in soil microcosm . We suggest that taking into account the specificity of surface- and biological activities of various biosurfactants they may promote the mineralization of sorbed PCBs in polluted soils, when the optimized biosurfactant-degrader combination is used. Chemosphere, 1999 Aug, 39(4), 627 - 39 A model for the formation and degradation of bound residues of the herbicide 14C-isoproturon in soil; Reuter S et al.; The humic monomer catechol was reacted with 14C-isoproturon and some of its metabolites, including 14C-4-isopropylaniline, in aqueous solution under a stream of oxygen . Only in the case of 14C-4-isopropylaniline, incorporation in oligomers, in fulvic acid-like polymers, and in humic acid-like polymers was observed . The main oligomer was identified by mass spectrometry as 4,5-bis-(4-isopropylphenylamino)-3,5-cyclohexadiene-1,2-dione . Oligomers and polymers containing bound 14C-4-isopropylaniline were subjected to biodegradation studies in a loamy agricultural soil during 55 days by quantifying 14CO2 evolved . In all cases, significant mineralization rates could be determined, which, however, were much smaller than those of free 14C-4-isoproturon and free 14C-4-isopropylaniline in the same soil. Appl Microbiol Biotechnol, 1999 Jun, 51(6), 865 - 71 Biodegradation of azo dyes in cocultures of anaerobic granular sludge with aerobic aromatic amine degrading enrichment cultures; Tan NC et al.; A prerequisite for the mineralization (complete biodegradation) of many azo dyes is a combination of reductive and oxidative steps . In this study, the biodegradation of two azo dyes, 4-phenylazophenol (4-PAP) and Mordant Yellow 10 (4-sulfophenylazo-salicylic acid; MY10), was evaluated in batch experiments where anaerobic and aerobic conditions were integrated by exposing anaerobic granular sludge to oxygen . Under these conditions, the azo dyes were reduced, resulting in a temporal accumulation of aromatic amines . 4-Aminophenol (4-AP) and aniline were detected from the reduction of 4-PAP . 5-Aminosalicylic acid (5-ASA) and sulfanilic acid (SA) were detected from the reduction of MY10 . Subsequently, aniline was degraded further in the presence of oxygen by the facultative aerobic bacteria present in the anaerobic granular sludge . 5-ASA and SA were also degraded, if inocula from aerobic enrichment cultures were added to the batch experiments . Due to rapid autoxidation of 4-AP, no enrichment culture could be established for this compound . The results of this study indicate that aerobic enrichment cultures developed on aromatic amines combined with oxygen-tolerant anaerobic granular sludge can potentially be used to completely biodegrade azo dyes under integrated anaerobic/aerobic conditions. Appl Microbiol Biotechnol, 1999 Jun, 51(6), 751 - 9 Biodegradation of EDTA; Nortemann B; The chelating agent ethylenediaminetetraacetate (EDTA) is not degraded by conventional biological and physicochemical methods for the treatment of wastewater and the purification of drinking water . Of the measurable organic compounds it is the one present at the highest concentration in many surface and drinking waters . In recent years, however, studies have demonstrated that EDTA can be degraded by specially enriched bacterial cultures and in wastewater treatment plants receiving EDTA-containing effluents . The amounts of EDTA released into the aquatic environment could thus be reduced by establishing appropriate biological wastewater treatment plants . This article describes the degradation of EDTA and its metal chelates by different bacterial cultures, catabolic steps in EDTA degradation, and biological methods for the removal of this chelating agent from wastewaters. J Biomed Mater Res, 1999, 48(4), 522 - 7 In vivo evaluation of a novel alginate dressing; Suzuki Y et al.; Alginate dressings are currently used in the management of epidermal and dermal wounds, and provide a moist environment that leads to rapid granulation and reepithelialization . However, a cytotoxic effect on proliferation of fibroblasts and residual material with inflammation in healing wounds have been reported recently . We have developed a new alginate dressing (AGA-100), which does not have an inhibitory effect on proliferation of fibroblasts . The purpose of this study was to evaluate the new alginate dressing with respect to wound healing in full- and partial-thickness pig wounds and with respect to biodegradation following implantation into rabbit muscle . Kaltostat and Sorbsan, both well-established commercial dressings, were used as control . The closure rate of full-thickness wounds treated with AGA-100 was significantly higher on day 15 compared with that with Kaltostat and Sorbsan . Reepithelialization rate of partial-thickness wounds treated with Sorbsan was statistically significantly lower on day 3 than those with the other two dressings . As to dressing debris remained in the healing wound, a large amount of foreign debris was noted in all the full-thickness wounds treated with Kaltostat or Sorbsan, while only about one-third of wounds treated with AGA-100 showed a little dressing debris . AGA-100 implanted into the muscle of rabbits was bioresorbed completely within 3 months . Therefore, dressing residue in AGA-100-treated full-thickness wounds might be fully absorbed in a few months . In conclusion, it is shown that our newly developed AGA-100 possesses superior properties compared with typical alginate dressings . Int J Biol Macromol, 1999 Jun-Jul, 25(1-3), 135 - 43 Extracellular degradation of medium chain length poly(beta-hydroxyalkanoates) by Comamonas sp; Quinteros R et al.; The PHA-degrading isolate, strain P37C, was enriched from residential compost for its ability to hydrolyze the medium chain length PHA, poly(beta-hydroxyoctanoate) (PHO) . It was subsequently found to grow on a wide range of PHAs, including both short chain length and medium chain length PHAs . The isolate was identified as belonging to the genus Comamonas . Strain P37C formed clear zones on poly(beta-hydroxybutyrate) (PHB), (PHO) and poly(beta-hydroxyphenylvalerate) (PHPV) overlay plates . PHA clear zone tubes were prepared using seven different kinds of PHAs, ranging from PHB with four-carbon repeating units, to poly(beta-hydroxyoctanoate-co-beta-hydroxyundecanoate) (PHOU) with 8- and 11-carbon repeating units . There was a direct correlation between PHA side chain length and rate of hydrolysis of the PHAs . A series of PHOUs containing varying percentages of unsaturated bonds were used to make a series of epoxidized PHOUs (PHOEs) with varying percentages of epoxy functions . Results of clear zone tube assays showed that these functionalized PHAs were all biodegradable by strain P37C, and there was no apparent correlation between rate of biodegradation and the proportion of functional groups in the PHAs . Biodegradability of these PHAs was verified using respirometry and enzyme assays . Cell-free supernatants containing activity toward PHAs were prepared, and strain P37C was shown to synthesize at least two distinct PHA depolymerases for the hydrolysis of SCL and MCL PHAs. Biochemistry, 1999 Jul 13, 38(28), 8879 - 83 Aminoethylcysteine can replace the function of the essential active site lysine of Pseudomonas mevalonii 3-hydroxy-3-methylglutaryl coenzyme A reductase; Bochar DA et al.; The biodegradative 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase of Pseudomonas mevalonii catalyzes the NAD(+)-dependent conversion of (S)-HMG-CoA to (R)-mevalonate . Crystallographic analysis of abortive ternary complexes of this enzyme revealed lysine 267 located at a position in the active site, suggesting that it might serve as the general acid/base for catalysis . Site-directed mutagenesis and subsequent chemical derivatization were therefore employed to investigate this active site lysine . Replacement of lysine 267 by alanine, histidine, or arginine resulted in mutant enzymes that lacked detectable activity . Lysine 267 was next replaced by the lysine analogues aminoethylcysteine and carboxyamidomethylcysteine . Using instead of the wild-type enzyme the fully active, cysteine-free mutant enzyme C156A/C296A, lysine 267 was first replaced by cysteine . Cysteine 267 of mutant enzyme C156A/C296A/K267C was then treated with bromoethylamine or iodoacetamide to insert aminoethylcysteine (AEC) or carboxyamidomethylcysteine at position 267 . The carboxyamidomethylcysteine derivative was inactive, whereas mutant enzyme C156A/C296A/K267AEC exhibited high catalytic activity . That aminoethylcysteine, but not other basic amino acids, can replace the function of lysine 267 documents both the importance of this residue and the requirement for a precisely positioned positive charge at the active site of the enzyme. J Pharm Pharmacol, 1999 May, 51(5), 623 - 30 Paradoxical cholinergic and purinergic vascular reactivity of rabbit thoracic aorta cold-stored in University of Wisconsin solution; Alexander B et al.; Endothelial dysfunction has been reported in donor blood vessels destined for organ transplantation following cold-storage preservation with University of Wisconsin solution (UW) . This was investigated in the present work . Segments of rabbit thoracic aorta were mounted on isometric fine-wire myographs at 37 degrees C and gassed with 95% O2/5% CO2 . Concentration-dependent vasodilatations to acetylcholine and adenosine-5'-triphosphate (ATP) were obtained in freshly-harvested rabbit aortic rings, with and without the endothelium, and after 8 days of cold-storage, at 4 degrees C, in either UW, Krebs-Bulbring buffer (KBB) or saline . The action of the nitric oxide synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) (100 microM) was evaluated upon the concentration-response curves to determine whether nitric oxide (NO) exerted any modulatory actions . Endothelium-dependent, NO-mediated responses to acetylcholine were unaltered after eight days of storage in UW, reduced after storage in KBB and absent after removal of the vascular endothelium, saline storage or after testing in the presence of L-NAME, suggesting improved NO-mediated endothelial function with the use of UW . Structural preservation was also confirmed using scanning electron microscopy . In contrast, endothelium-dependent responses to ATP were unchanged after eight days of storage in KBB but were reduced after storage in UW and saline, suggesting purinergic (ATP) endothelial dysfunction after storage in UW . L-NAME markedly reduced vasodilatation to ATP in freshly harvested rings and after eight days of storage in KBB . This reduction was statistically significant (P < 0.05, Student's two tailed, unpaired t-test) at -log (M) ATP concentrations of 5.5, 5.0, 4.5, 4.0 and 3.5 . NO-dependent vasodilatation to ATP was not attenuated by L-NAME in UW-stored rings . Eight days' UW-storage of rabbit thoracic aortic rings appeared to have differential and paradoxical effects upon NO-dependent vasodilatation to acetylcholine and ATP . Morphological observations using electron microscopy suggested that UW preserved the vascular endothelium and this was verified by retained vascular reactivity of endothelium-dependent vasodilatations to acetylcholine . UW-storage however, significantly reduced endothelium-dependent relaxation to ATP thereby suggesting that P2Y-purinoceptors, which are located on the vascular endothelium, may be more susceptible to biodegradation than cholinergic receptors and may be responsible for endothelial dysfunction following transplantation. Can J Microbiol, 1999 Mar, 45(3), 201 - 8 Biodegradation of cyanide compounds by a Pseudomonas species (S1); Dhillon JK et al.; A Pseudomonas sp . (S1), isolated from soil by an enrichment technique was tested for its potential to degrade different cyanide compounds . Further, biodegradation/biotransformation of binary mixtures of the cyanide compounds by the culture was also studied . The results indicated that the culture could grow on the following nitriles by using them as carbon and nitrogen sources: acetonitrile, butyronitrile, acrylonitrile, adiponitrile, benzonitrile, glutaronitrile, phenylacetonitrile, and succinonitrile . Studies on the biodegradation of these cyanide compounds in binary mixtures showed that the presence of acrylonitrile or KCN delayed the degradation of acetonitrile in a mixture, while none of the other cyanide compounds affected the degradation of one another . The transformation products of the nitriles were their corresponding acids, and similarly, KCN was also directly transformed to formic acid . Studies on the transformation of these cyanide compounds showed that the rate of transformation of nitriles to their corresponding carboxylic acids was acrylonitrile > acetonitrile > adiponitrile > benzonitrile > KCN . This culture has the unique characteristic of transforming representatives of saturated aliphatic, aliphatic olefinic, aromatic, and aralkyl nitriles, as well as alkali cyanide, to their corresponding carboxylic acids. Rapid Commun Mass Spectrom, 1999 Jun, 13(12), 1124 - 1128 Molecular distribution of some commercial nonylphenol ethoxylates using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; Ayorinde FO et al.; Nonylphenol ethoxylates (NPEs) belong to a group of nonionic surfactants that are collectively referred to as alkylphenol ethoxylates (APEs) . APEs find widespread use in heavy-duty commercial and household cleaning formulations, shampoos, and industrial processing, i.e . textile manufacture . Their environmental impact depends on the molecular distribution and the extent of their biodegradation in municipal sewage systems, waterways and rivers . We have established two sample preparation methods that have enabled the determination of the molecular distributions of six commercial nonylphenol ethoxylates using matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) . In both methods, alpha-cyano-4-hydroxycinnamic acid, dissolved in acetonitrile/tetrahydrofuran, was used as the matrix . In one set of experiments, the NPEs were dissolved in an acetonitrile/tetrahydrofuran solvent system prior to mixing with the matrix solution, and the resulting MALDI-TOF mass spectra produced mostly sodiated molecules {M + Na}(+) . The NPEs, all having the formula 4-(C(9)H(19))-C(6)H(4)-(OCH(2)CH(2))(n)-OH, are Surfonic (R)N-95, N-100, N-102, N-120, N-150 and N-300 . Surfonic N-95 and N-100 gave n values of 5-20; Surfonic N-102, N-120, N-150, and N-300 gave n values of 5-21, 5-22, 8-25 and 15-40, respectively . In order to develop a sample preparation method that could be used with less polar NPEs, we dissolved the NPEs (except N-300) in pentane prior to mixing with the matrix solution, and found that the MALDI spectral quality was unaffected by the solvent systems . J Biomater Appl, 1999 Jul, 14(1), 67 - 90 Biomedical applications of polyurethanes: a review of past promises, present realities, and a vibrant future; Zdrahala RJ et al.; Polyurethanes, having extensive structure/property diversity, are one of the most bio- and blood-compatible materials known today . These materials played a major role in the development of many medical devices ranging from catheters to total artificial heart . Properties such as durability, elasticity, elastomer-like character, fatigue resistance, compliance, and acceptance or tolerance in the body during the healing, became often associated with polyurethanes . Furthermore, propensity for bulk and surface modification via hydrophilic/hydrophobic balance or by attachments of biologically active species such as anticoagulants or biorecognizable groups are possible via chemical groups typical for polyurethane structure . These modifications are designed to mediate and enhance the acceptance and healing of the device or implant . Many innovative processing technologies are used to fabricate functional devices, feeling and often behaving like natural tissue . The hydrolytically unstable polyester polyurethanes were replaced by more resistant but oxidation-sensitive polyether polyols based polyurethanes and their clones containing silicone and other modifying polymeric intermediates . Chronic in vivo instability, however, observed on prolonged implantation, became a major roadblock for many applications . Presently, utilization of more oxidation resistant polycarbonate polyols as soft segments, in combination with antioxidants such as Vitamin E, offer materials which can endure in the body for several years . The applications cover cardiovascular devices, artificial organs, tissue replacement and augmentation, performance enhancing coatings and many others . In situ polymerized, cross-linked systems could extend this biodurability even further . The future will expand this field by revisiting chemically-controlled biodegradation, in combination with a mini-version of RIM technology and minimally invasive surgical procedures, to form, in vivo, a scaffold, by delivery of reacting materials to the specific site in the body and polymerizing the mass in situ . This scaffold will provide anchor for tissue regeneration via cell attachment, proliferation, control of inflammation, and healing. J Biomed Mater Res, 1999 Oct, 47(1), 79 - 84 Polypeptide resurfacing method improves fibroblast's adhesion to hyaluronan strands; Hu M et al.; Hyaluronic acid (hyaluronan, HyA) is a matrix component that takes part in cell adhesion and growth in normal and repaired tissues . Since it is soluble in water, HyA has been of limited use in tissue engineering of artificial matrices . Recent studies demonstrate that polypeptides have the twin advantages of reducing solubility of HyA and improving cellular attachment via cell surface adhesion molecule receptors . This paper describes a new approach of using a polypeptide resurfacing method to enhance the attachment of cells to HyA strands . HyA strands were crosslinked by glutaraldehyde and then resurfaced with poly-D-lysine, poly-L-lysine, glycine, or glutamine . After inoculation with fibroblasts in vitro, modified HyA was evaluated with histological and immunohistochemical staining methods for cell adhesion and proliferation . Modified HyA with fibroblast cells also were implanted in vivo . The results show that (1) both polylysines enhanced fibroblast adhesion to crosslinked HyA strands; (2) HyA strands were able to be crosslinked well by 3 days of treatment in glutaraldehyde, and as a biomaterial they could resist biodegradation; (3) modified HyA has good biocompatibility, both in vitro and in vivo . The results demonstrate that HyA material resurfaced by polypeptides has positive advantages for cellular adhesion . Resurfaced HyA has much potential as an improved biomaterial for clinical usage . J Biomed Mater Res, 1999, 48(3), 265 - 76 Osteoconductivity and bone-bonding strength of high- and low-viscous bioactive bone cements; Kobayashi M et al.; A study was conducted to evaluate the osteoconductivity and bone-bonding ability of two types of bioactive bone cement, both consisting of apatite and wollastonite containing glass-ceramic powder (AW-P), fused silica glass powder (SG-P), submicron fumed silica as an inorganic filler, and bisphenol-a-glycidyl methacrylate (Bis-GMA) based resin as an organic matrix . The cements had two kinds of formulas: one (dough-type cement; designated DTC) composed of 85% (w/w) filler and 15% resin, which was developed for fixation of the acetabular component in total hip arthroplasty and could be handled manually; and one (injection-type cement; designated ITC) composed of 79% (w/w) filler and 21% resin . ITC was developed for fixation of the femoral component and, because it had a lower viscosity than DTC, could be injected . The DTC and ITC both contained 73% AW-P, 25% SG-P, and 2% fumed silica in the weight ratio of the filler component . Two other types of cement, both of which consisted of 83.3% AW-P or SG-P, 1.7% fumed silica, and 15% resin, were used as reference material (designated AWC or SGC) for a detaching test . Following the packing of bone defects in the rat tibiae with either DTC or ITC, histological examination revealed that the DTC and ITC had both directly contacted the bone and were almost completely surrounded by bone by 16 weeks after the surgery and that no marked biodegradation had occurred at 52 weeks postimplantation . Rectangular plates (2 x 10 x 15 mm) of AWC, DTC, ITC, and SGC were implanted into the metaphysis of the tibia of male rabbits and the failure load was measured by a detaching test at 10 and 25 weeks after implantation . The failure loads of AWC, DTC, ITC, and SGC were 3.65, 2.21, 2.44, and 0.04 kgf at 10 weeks and 4.87, 2 . 81, 2.82, and 0.13 kgf at 25 weeks, respectively . Observation of the bone-implant interface by scanning electron microscopy and energy dispersive X-ray microanalysis revealed that all the samples except SGC formed direct contact with the bone and that only AWC-implanted tibiae had a layer of a low calcium and phosphorus level at the bone-implant interface . Results showed that DTC and ITC have excellent osteoconductivity and bone-bonding ability under non-weight-bearing conditions . Biotechnol Bioeng, 1999 Aug 5, 64(3), 290 - 7 Poly(ethylene glycol)-modified ligninase enhances pentachlorophenol biodegradation in water-solvent mixtures Wang P, Woodward CA, Kaufman EN. Polychlorinated hydrocarbons are prevalent environmental contaminants whose rates of biodegradation are limited by their minimal solubilities in aqueous solutions where the biological reactions take place . In this study, ligninase (LiP) from Phanerochaete chrysosporium was modified by poly(ethylene glycol) to enhance its activity and stability for the biodegradation of pentachlorophenol (PCP) in the presence of acetonitrile (MeCN), a water-miscible solvent . The modified enzyme retained 100% of its activity in aqueous solutions and showed enhanced tolerance against the organic solvent . The activity of the modified enzyme was found to be over twice that of the native enzyme in the presence of 10% (v/v) MeCN . The solubility of PCP was enhanced significantly by the addition of MeCN to aqueous solutions, such that it was over 10-fold more soluble in the presence of 15% (v/v) MeCN than in pure aqueous buffer solution (from 0.06 to 0.65 mM) . Capitalizing on the enhanced substrate solubility and the increased activity of the modified enzyme, the catalytic efficiency of the modified LiP in solutions containing 15% MeCN was over 11-fold higher than that of the native enzyme in buffer solutions (pH 4.2) in unoptimized reactor systems (from 44 to 480 mol PCP/mol LiP.h) . Continued research both in the use of organic solvents to increase the availability of recalcitrant contaminants and in the modification of enzymes to enhance their activity and stability in such solvents promises to dramatically affect our ability to remediate contaminated sites . Published by John Wiley & Sons. J Biomed Mater Res, 1999 Sep 15, 46(4), 475 - 84 In vitro modulation of macrophage phenotype and inhibition of polymer degradation by dexamethasone in a human macrophage/Fe/stress system; Casas J et al.; A new in vitro accelerated biological model, the macrophage-FeCl2-stress system was used for the evaluation of dexamethasone (DEX)-polymer formulations . This model combines the effects of cells (macrophages), transition metal ions (Fe2+), and polymer stress to promote material biodegradation . The cell and material effects of DEX, either in solution or incorporated into a polyetherurethane matrix (DEX/PEU), were monitored . Cell morphology and hydroperoxide formation in the polymer during cell culturing were characterized . After a subsequent treatment with FeCl2 the development of environmental stress cracking in the polymer was evaluated . We attempted to duplicate the biodegradation of PEU in terms of environmental stress cracking (ESC) . Our results support the direct involvement of macrophages in polyetherurethane oxidation, probably by inducing hydroperoxide formation in the polymer structure . Under the influence of stress or strain, polymers with sufficient hydroperoxides degrade in the presence of Fe2+ metal ions in a manner that closely resembles the stress cracking that is observed in vivo . By contrast, polymers treated with either agents that inhibit cell activation and/or the oxidative burst, or with cells with no oxidative burst did not show signs of the biodegradative process . We demonstrated a reduction in hydroperoxide formation and no later ESC development in macrophage-cultured PEU in the presence of DEX in solution or in DEX-loaded PEU . We believe the prevention of initial polymer oxidation by reducing the cell's potential to produce oxidative stress at the tissue-biomaterial interface can directly inhibit the ESC degradation of chronically implanted polymers . The in vitro macrophage-Fe-stress system is a valuable tool for reliable assessment and cost-effective evaluation of biomaterials . Biotechnol Bioeng, 1999 Jul 20, 64(2), 221 - 31 Biodegradation of neutralized sarin; Zhang Y et al.; This research investigated the biotransformation of IMPA, the neutralization product of the nerve agent Sarin, by a microbial consortia . As mandated by the Chemical Weapons Convention signed by 132 countries in 1993, all chemical warfare agents are to be destroyed within ten years of ratification . Technologies must be developed to satisfy this commitment . This paper presents data from a biodegradation kinetics study and background information on the biological transformation of IMPA . Microbial transformation of organophosphate nerve agents and organophosphate pesticide intermediates can be incorporated into a treatment process for the fast and efficient destruction of these similar compounds . Sarin (isopropyl methylphosphonofluoridate), also known as GB, is one of several highly neurotoxic chemical warfare agents that have been developed over the past 50 to 60 years . Four mixed cultures were acclimated to the Sarin hydrolysis product, isopropyl methylphosphonic acid (IMPA) . Two of these cultures, APG microorganisms and SX microorganisms, used IMPA as the sole phosphorus source . Extended exposure to IMPA improved the cultures' abilities to degrade IMPA to form methylphosphonic acid (MPA) and inorganic phosphate . The presence of free phosphate in the reactor suppressed the degradation of IMPA . IMPA did not inhibit either cultural consortia within the tested concentration range (0 to 1250 mg/L) . The numax was 120.9 mg/L/day for the SX microorganisms and 118.3 mg/L/day for the APG microorganisms . Initial IMPA concentrations of 85 to 90 mg/L were degraded to nondetectable levels within 75 h . These results demonstrate the potential for biodegradation to serve as a complementary treatment process for the destruction of stockpiled Sarin . Chemosphere, 1999 Jun, 38(14), 3219 - 35 An 'inherent' biodegradability test for oil products: description and results of an international ring test . CONCAWE Biodegradation Task Force; Battersby NS et al.; Current test guidelines for assessing 'inherent' (potential) biodegradability were designed for water-soluble, organic compounds of low volatility and are unsuitable for most oil products . It was against this background, that CONCAWE (the oil companies' European organisation for environment, health and safety) formed a task force to develop a standard test protocol for assessing the 'inherent' biodegradability of oil products. J Biomater Sci Polym Ed, 1999, 10(6), 621 - 39 Synthesis and enzymatic degradation of optically active depsipeptide copolymers; Shirahama H et al.; This paper describes the synthesis and biodegradation of copolymers of cyclic depsipeptide with epsilon-caprolactone (CL) or lactide (LA) . Optically active cyclic depsipeptides, 3,6-dimethyl-2,5-morpholinediones (DMOs), were prepared by the reaction of an amino acid (D-, L-, or DL-alanine) with a hydroxy acid derivative (DL-2-bromopropionyl bromide) . These isomers are abbreviated as D-DMO, L-DMO and DL-DMO respectively, according to the names of alanine isomers . Then, we have prepared the copolymers of DMO isomers with CL using tin(II) octylate as a catalyst . The NMR spectra and thermal properties of DMO/CL copolymers revealed that these copolymers exist randomly . The enzymatic degradation of the copolymers has been examined using Rhizopus delemar lipase, cholesterol esterase (from Pseudomonas sp.), and Proteinase K (from Tritirachium album) . Cholesterol esterase and Proteinase K show high degradability, while the lipase shows little degradation . Among the enzymes used, only Proteinase K could recognize the isomerism of DMO, resulting in the following order of degradability: copoly(L-DMO/CL) > copoly(DL-DMO/CL) > copoly(D-DMO/CL), i.e . this enzyme has the highest substrate specificity for naturally occurring L-alanine . Further, we have prepared the random copolymers of L-DMO with lactide (L-LA or DL-LA), and evaluated the enzymatic degradation of the copolymers by Proteinase K . The introduction of a small amount (up to c . 10 mol%) of L-DMO unit into LA homopolymers brought about greater degradability compared with LA homopolymers . In particular, L-DMO/L-LA copolymers with high degradability have been obtained without significant decrease in the mechanical and thermal properties of L-LA homopolymer. Can J Microbiol, 1999 Feb, 45(2), 130 - 7 Influence of chemical surfactants on the biodegradation of crude oil by a mixed bacterial culture; Van Hamme JD et al.; The effects of surfactant physicochemical properties, such as the hydrophile-lipophile balance (HLB) and molecular structure, on the biodegradation of 2% w/v Bow River crude oil by a mixed-bacterial culture were examined . Viable counts increased 4.6-fold and total petroleum hydrocarbon (TPH) biodegradation increased 57% in the presence of Igepal CO-630, a nonylphenol ethoxylate (HLB 13, 0.625 g/L) . Only the nonylphenol ethoxylate with an HLB value of 13 substantially enhanced biodegradation . The surfactants from other chemical classes with HLB values of 13 (0.625 g/L) had no effect or were inhibitory . TPH biodegradation enhancement by Igepal CO-630 occurred at concentrations above the critical micelle concentration . When the effect of surfactant on individual oil fractions was examined, the biodegradation enhancement for the saturate and aromatic fractions was the same . In all cases, biodegradation resulted in increased resin and asphaltene concentrations . Optimal surfactant concentrations for TPH biodegradation reduced resin and asphaltene formation . Chemical surfactants have the potential to improve crude oil biodegradation in complex microbial systems, and surfactant selection should consider factors such as molecular structure, HLB, and surfactant concentration. Biochem J, 1999 Jul 1, 341 ( Pt 1), 113 - 7 Molecular cloning of aryl-alcohol oxidase from the fungus Pleurotus eryngii, an enzyme involved in lignin degradation; Varela E et al.; Aryl-alcohol oxidase (AAO), an extracellular enzyme characteristic of fungi from the genus Pleurotus, constitutes a source for H2O2 required in lignin biodegradation . The gene aao has been cloned, sequenced and characterized for the first time in Pleurotus eryngii . Both cDNA and genomic libraries were screened with probes obtained by PCR using as primers oligonucleotides corresponding to the N-terminus and internal sequences of AAO . DNA sequences from positive clones showed a unique open reading frame of 1779 nucleotides interrupted by 12 introns . The conceptual translation of the protein agrees with the partial amino acid sequences obtained from protein sequencing . A search for proteins with related amino-acid sequences revealed that glucose oxidase from Aspergillus niger has 33% identity and 51% similarity . A comparison with other oxidoreductases showed common motifs in both N- and C-terminal regions corresponding, respectively, to the FAD-binding region and the enzyme active site . However, AAO probably has structural differences with other oxidases, as deduced from its unique ability to generate H2O2 from the oxidation of aromatic alcohols. Biomed Chromatogr, 1999 May, 13(3), 220 - 4 Biodegradation of pentachlorophenol (PCP) by white rot fungal strains screened from local sources and its estimation by high-performance liquid chromatography; Tayal AK et al.; White rot fungal strains screened from local sources (wood trunks and from effluents of pulp and paper industry) were tested for their ability to biodegrade polymeric compounds, viz . polymeric dyes (crystal violet and brilliant green) and chlorinated phenol (pentachlorophenol) . Two of the most promising strains showing maximum degradation of polymeric dyes were selected to study the biodegradation potential and pattern of biodegradation of pentachlorophenol (PCP), a commonly used leather preservative and a potential carcinogen . PCP was quantitatively estimated and analysed by high-performance liquid chromatography (HPLC) . Conditions were optimized for the measurement of PCP on HPLC, which were: mobile phase, 60% acetonitrile and 40% water; flow rate, 1 mL/ min; column, mu Bondapack C18 RP and UV detector at 238 nm . One of the white rot fungal strains isolated from wood trunk showed a maximum 68% biodegradation of PCP in liquid-buffered medium in 16 days . The biodegradation pattern of PCP followed a pseudo-first-order kinetics . Studies on enhancement of biodegradation of polymeric dyes and PCP showed that the kinetics of biodegradation is greatly improved by the presence of manganese ions, H2O2 and glucose in the medium . This strongly suggests the involvement of peroxidase enzyme machinery of white rot fungus in the biodegradation process of PCP. Prikl Biokhim Mikrobiol, 1999 Mar-Apr, 35(2), 165 - 72 {Protective effects of agar during immobilization of strains capable to degrade aromatic compounds}; Fedorov AIu et al.; A study of utilization of toxic monoaromatic compounds by microbial cells incorporated into agar matrix revealed positive effects of immobilization on the rate and completeness of biodegradation . This increase in the degrading activity is probably due to a strong protective effect of the polysaccharide carrier . The protective properties of agar are not due to sorptional and diffusional processes in the matrix . These properties were shown to be associated with the formation of a specific extracellular membrane around microcolonies. Chemosphere, 1999 Jun, 38(15), 3627 - 36 Enhancement of PAH biodegradation in soil by physicochemical pretreatment; Bonten LT et al.; The effects were studied of short-term heating of contaminated soil and its soaking in an organic solvent on the subsequent biodegradation of PAHs . In a clayey dredged sludge with a high organic-matter content (12%), heating at 120 degrees C for one hour increased the degree of degradation after 21 days of an aged PAH contamination from 9.5 +/- 0.7% to 27 +/- 5% . Lower temperatures resulted in smaller increases . The observed increase in biodegradation is caused by either transfer of PAHs from sorption sites with low desorption rates to those with high ones or transformation of slow-sorption sites into fast-sorption ones . Soaking of the above sludge in a 4:1 (v/v) acetone-water mixture increased the degree of degradation from 9.5 +/- 0.7% to 20.4 +/- 1.4%, probably as a result of dissolution of the PAHs in the pore liquid during soaking . Thermal pretreatment of a contaminated sandy soil with a low organic-matter content showed no significant effect on the degradation of aged PAHs . Soaking of the sandy soil increased the degradation of only PAHs of high molecular weight, namely from 24 +/- 5% to 48 +/- 7%. Chemosphere, 1999 Jun, 38(15), 3463 - 72 Biodegradation of diesel oil by cold-adapted microorganisms in presence of sodium dodecyl sulfate; Margesin R et al.; The effect of different concentrations of the anionic surfactant sodium dodecyl sulfate (SDS) on biodegradation of diesel oil was assessed during 32 days at 10 degrees C, under simulated environmental conditions, in liquid culture and in an alpine soil . Low SDS concentrations (50-100 mg l-1) significantly enhanced oil biodegradation by a psychrotrophic inoculum in liquid culture, whereas higher SDS concentrations (500-1000 mg l-1) inhibited hydrocarbon biodegradation . Oil biodegradation by the indigenous microorganisms in soil was inhibited at all SDS concentrations tested . The surfactant itself was rapidly biodegraded both in liquid culture and in soil. J Biotechnol, 1999 Apr 15, 69(2-3), 151 - 62 Glucose 1- and 2-oxidases from fungal strains: isolation and production of monoclonal antibodies; Karmali A et al.; Monoclonal antibodies (Mabs) against purified glucose 2-oxidase (EC 1.1.3.10) from Coriolus versicolor were raised by hybridoma technology using Sp2/0 myeloma cells as a fusion partner . Hybrid growth was observed in 42% of culture wells and 30% of these (i.e . 30 culture wells) contained anti-glucose 2-oxidase activity . Three positive wells containing hybrid cell lines were selected and cloned twice by the limiting dilution method and two hybridoma clones (E1A5 and E1A6) secreting Mabs were selected at random for purification and characterisation purposes . Both cell lines secreted Mabs of IgM class which were purified by gel filtration chromatography on a Sephacryl S-200 column with a final recovery of 80% and a purification factor of 16 . The purified preparations were apparently homogeneous on native PAGE running with a M(r) of 950 kDa . Mabs were highly specific for glucose 2-oxidase as determined by Western blotting . These Mabs also crossreacted with glucose 1- and 2-oxidases from other fungal sources (Phanerochaeta chrysosporium, Penicillium amagasakiense and Aspergillus niger) as determined by Western blotting and by ELISA . Both glucose 1- and 2-oxidases from C . versicolor, P . chrysosporium, P . amagasakiense and A . niger were purified by hydrophobic interaction chromatography on Sepharose 4B-triazine dye with a recovery of enzyme activity in the range 85-92% . Purified preparations of glucose oxidases from fungal strains were apparently homogeneous on native PAGE . Glucose 2-oxidases were more hydrophobic than glucose 1-oxidases as determined by their chomatographic behaviour on Sepharose 4B-Cibacron Red G-E which could be used to study their roles in lignin biodegradation. Tissue Eng, 1999 Apr, 5(2), 127 - 38 Biodegradation of hydrogel carrier incorporating fibroblast growth factor; Tabata Y et al.; In vivo release of basic fibroblast growth factor (bFGF) from a biodegradable gelatin hydrogel carrier was compared with the in vivo degradation of hydrogel . When gelatin hydrogels incorporating 125I-labeled bFGF were implanted into the back subcutis of mice, the bFGF radioactivity remaining decreased with time and the retention period was prolonged with a decrease in the water content of the hydrogels . The lower the water content of 125I-labeled gelatin hydrogels, the faster both the weight of the hydrogels and the gelatin radioactivity remaining decreased with time . The decrement profile of bFGF remaining in hydrogels was correlated with that of hydrogel weight and gelatin radioactivity, irrespective of the water content . Subcutaneous implantation of bFGF-incorporating gelatin hydrogels into the mice induced significant neovascularization . The retention period of neovascularization became longer as the water content of the hydrogels decreased . To study the decrease of activity of bFGF when implanted, bFGF-incorporating hydrogels were placed in diffusion chamber and implanted in the mouse subcutis for certain periods of time . When hydrogels explanted from the mice were again implanted, significant neovascularization was still observed, indicating that most of the biological activity of bFGF was retained in the hydrogels . It was concluded that, in our hydrogel system, biologically active bFGF was released as a result of in vivo degradation of the hydrogel . The release profile was controllable by changing the water content of hydrogels. Biotechnol Prog, 1999 May, 15(3), 517 - 21 Organophosphorus hydrolase-based assay for organophosphate pesticides Rogers KR, Wang Y, Mulchandani A, Mulchandani P, Chen W. We report a rapid and versatile organophosphorus hydrolase (OPH)-based method for measurement of organophosphates . This assay is based on a substrate-dependent change in pH at the local vicinity of the enzyme . The pH change is monitored using fluorescein isothiocyanate (FITC), which is covalently immobilized to the enzyme . This method employs the use of poly(methyl methacrylate) beads to which the FITC-labeled enzyme is adsorbed . Analytes were then measured using a microbead fluorescence analyzer . The dynamic concentration range for the assay extends from 25 to 400 &mgr;M for paraoxon with a detection limit of 8 &mgr;M . Organophosphorus insecticides measured using this technique included ethylparathion, methylparathion, dursban, fensulfothion, crotoxyphos, diazinon, mevinphos, dichlorvos, and coumaphos . This technique was used to measure coumaphos in biodegradation samples of cattle dip wastes and showed a high correlation (r2 = 0.998) to an HPLC method. Appl Environ Microbiol, 1999 Jun, 65(6), 2376 - 81 Earthworm egg capsules as vectors for the environmental introduction of biodegradative bacteria; Daane LL et al.; Earthworm egg capsules (cocoons) may acquire bacteria from the environment in which they are produced . We found that Ralstonia eutropha (pJP4) can be recovered from Eisenia fetida cocoons formed in soil inoculated with this bacterium . Plasmid pJP4 contains the genes necessary for 2,4-dichlorophenoxyacetic acid (2,4-D) and 2, 4-dichlorophenol (2,4-DCP) degradation . In this study we determined that the presence of R . eutropha (pJP4) within the developing earthworm cocoon can influence the degradation and toxicity of 2,4-D and 2,4-DCP, respectively . The addition of cocoons containing R . eutropha (pJP4) at either low or high densities (10(2) or 10(5) CFU per cocoon, respectively) initiated degradation of 2,4-D in nonsterile soil microcosms . Loss of 2,4-D was observed within the first week of incubation, and respiking the soil with 2,4-D showed depletion within 24 h . Microbial analysis of the soil revealed the presence of approximately 10(4) CFU R . eutropha (pJP4) g-1 of soil . The toxicity of 2,4-DCP to developing earthworms was tested by using cocoons with or without R . eutropha (pJP4) . Results showed that cocoons containing R . eutropha (pJP4) were able to tolerate higher levels of 2,4-DCP . Our results indicate that the biodegradation of 2, 4-DCP by R . eutropha (pJP4) within the cocoons may be the mechanism contributing to toxicity reduction . These results suggest that the microbiota may influence the survival of developing earthworms exposed to toxic chemicals . In addition, cocoons can be used as inoculants for the introduction into the environment of beneficial bacteria, such as strains with biodegradative capabilities. J Craniomaxillofac Surg, 1999 Apr, 27(2), 124 - 33 Fixation of mandibular body osteotomies using biodegradable amorphous self-reinforced (70L:30DL) polylactide or metal lag screws: an experimental study in sheep; Kallela I et al.; Mandibular body osteotomies were fixed in nine sheep using new totally amorphous (70L:30DL), self-reinforced, polylactide (SR-PLA) lag screws and in nine sheep using standard stainless steel lag screws . No intermaxillary fixation was used . During follow-up, radiological, histological and microradiological studies were undertaken at 3, 6, 12 and 24 weeks . In both groups, all osteotomies consolidated at similar rates and no adverse reaction to the screws was seen . However, displacements of the fixed osteotomy fragments were common in both groups during the first 3 weeks . The biocompatibility of SR-PLA during the follow-up period was found to be good . Only initial signs of biodegradation were seen . The results of this study indicate that (70L:30DL) SR-PLA has potential for use as a fixation screw material in oral and maxillofacial surgery, and that further studies using this material are justified. Appl Microbiol Biotechnol, 1999 Apr, 51(4), 532 - 5 Aerobic degradation of a hydrocarbon mixture in natural uncontaminated potting soil by indigenous microorganisms at 20 degrees C and 6 degrees C; Eriksson M et al.; A hydrocarbon mixture containing p-xylene, naphthalene, Br-naphthalene and straight aliphatic hydrocarbons (C14 to C17) was aerobically degraded without lag phase by a natural uncontaminated potting soil at 20 degrees C and 6 degrees C . Starting concentrations were approximately 46 ppm for the aromatic and 13 ppm for the aliphatic compounds . All aliphatic hydrocarbons were degraded within 5 days at 20 degrees C, to levels below detection (ppb levels) but only down to 10% of initial concentration at 6 degrees C . Naphthalene was degraded within 12 days at 20 degrees C and unaffected at 6 degrees C . At 20 degrees C p-xylene was degraded within 20 days, but no degradation occurred at 6 degrees C . Br-naphthalene was only removed down to 30% of initial concentration at 20 degrees C, with no significant effect at 6 degrees C . The biodegradation was monitored with head space solid-phase microextraction and gas chromatography-mass spectrometry. Biodegradation, 1998, 9(6), 433 - 42 Thiomorpholine and morpholine oxidation by a cytochrome P450 in Mycobacterium aurum MO1 . Evidence of the intermediates by in situ 1H NMR; Combourieu B et al.; Spectrophotometric assays of Mycobacterium aurum MO1 cells extracts gave evidence of a soluble cytochrome P450, involved in the degradative pathway of morpholine, a waste product from the chemical industry . In order to get further information, the kinetics of the biodegradation of the sulfur analogue thiomorpholine was monitored by using in situ nuclear magnetic resonance (NMR) . This technique allowed the identification of two intermediates: the sulfoxide of thiomorpholine resulting from S-oxidation and thiodiglycolic acid owing to ring cleavage . The S-oxidation (S-->SO) represents one of the well-known reactions catalyzed by cytochromes P450 . The inhibitory effect of metyrapone, a cytochrome P450 inhibitor, on the thiomorpholine and morpholine degradative abilities of M . aurum MO1 confirmed the involvement of a cytochrome P450 . These results and the decrease of the rate of formation of the first intermediate during the morpholine degradation, 2-(2-aminoethoxy) acetate, proved the key role of the cytochrome P450 in the early events of the biodegradation, i.e., in the C-N bond cleavage. Biodegradation, 1998, 9(6), 423 - 31 Application of 13C NMR to investigate the transformations and biodegradation of organic materials by wood- and soil-feeding termites, and a coprophagous litter-dwelling dipteran larva; Hopkins DW et al.; Solid-state 13C nuclear magnetic resonance spectroscopy has been used to characterize the C in samples of the food (wood), gut contents and faeces from the wood-feeding termite, Microcerotermes parvus; soil in the guts and mound material from the soil-feeding termite, Thoracotermes macrothorax; and the food and faeces from the litter-feeding, coprophagous larvae of the dipteran fly, Bibio marci . Spectra from the wood-feeding termite indicated preferential loss of polysaccharide and accumulation of lignin with some modification to the O-aromatic-C and methoxyl-C (O-methyl-C) components during passage through the gut . Spectra for the soil-feeding termite indicated little change in the distribution of 13C between resonances following passage through the gut, except for some evidence of preferential polysaccharide loss . Interpretation of the spectra from these organisms was restricted by the relatively low C content of the soils and mound material, and by the large contribution to the NMR spectra from the gut tissue rather than the gut contents . Spectra for the litter-feeding dipteran larvae indicated preferential feeding on the polysaccharide-rich component of the litter and then overall loss of polysaccharide-C and accumulation of both aromatic-C and methoxyl-C in the gut . These changes were greater for the second passage than for the first passage through the gut, suggesting that principally mechanical and physical changes occurred initially and that chemical digestion was prevalent during the second passage. Biochem Biophys Res Commun, 1999 May 27, 259(1), 212 - 9 Coupling of manganese peroxidase-mediated lipid peroxidation with destruction of nonphenolic lignin model compounds and 14C-labeled lignins; Kapich A et al.; Linoleic acid, the predominant unsaturated fatty acid (UFA) in the lipids of wood-rotting fungi, was oxidized by manganese peroxidase (MnP) from the white-rot fungus Phlebia radiata through a peroxidation mechanism . The peroxidation was markedly stimulated by hydrogen peroxide . UFAs that are substrates for lipid peroxidation and surfactants that emulsify water-insoluble components were essential for the MnP-catalyzed destruction of a nonphenolic beta-O-4-linked lignin model compound (LMC) . Moreover, both components stimulated the MnP-catalyzed mineralization of 14C-labeled synthetic lignin and 14C-labeled wheat straw . A high level of destruction was obtained in reaction systems with Tween 80 acting both as surfactant and source of UFAs . The presence of the linoleic acid in reaction systems with MnP and Tween 80 additionally enhanced rate and level of LMC destruction and lignin mineralization . The results indicate that lipid peroxidation may play an important role in lignin biodegradation by wood-rotting basidiomycetes and support the hypothesis of coupling between the processes . Ecotoxicol Environ Saf, 1999 May, 43(1), 47 - 56 Biodegradation of s-triazine compounds by a stable mixed bacterial community; Kontchou CY et al.; The potential for biodegradation of s-triazine pesticides was investigated in laboratory batch and sequence batch experiments using a stable mixed bacterial community enriched on atrazine . The experiments were performed aerobically in a mineral salt solution complemented with a mixture of s-triazines as sole carbon and energy sources . Comparisons were made between the efficiency of the inoculum for atrazine degradation in mineral salt solution and in wastewater . In batch cultivation, atrazine, simazine, hydroxyatrazine, and terbutylazine were degraded to concentrations below 0.1 mg/liter after 6 days; evidence of the mineralization was the detection of 14CO2 from {U-ring-14C} atrazine and the production of nitrate and chloride ions . The low degradation rate observed for cyanuric acid and desethylatrazine suggests that degradation proceeded via N-dealkylation and dechlorination . Nevertheless, degradation of ametryne and cyromazine presume the involvement of other degradation pathways . Evidence was given that presence of other additional carbon sources is not an obstacle to atrazine biodegradation, since better results were obtained using wastewater . Rev Argent Microbiol, 1999 Jan-Mar, 31(1), 42 - 8 {Degradation of naphthalene-2-sulfonate by strains of Micromonospora}; Vidal CM et al.; It was possible to isolate several strains of Micromonospora sp . from waters of Rio Reconquista . They all were filamentous bacteria with lateral spores, highly resistant to Cr(III) and another heavy metal cations . All these strains were able to grow on naphthalene-2-sulphonate as sole carbon source in a mineral medium . The biodegradation of the xenobiotic proceeds via the formation of salicylate and gentisate . These compounds have been isolated and mass spectrometry identified. Chemosphere, 1999 Jun, 38(13), 3109 - 17 Microbial degradation of 4-chlorophenol by microorganisms entrapped in carrageenan-chitosan gels; Wang J et al.; A new cell immobilization method based on the replacement of KCl by KCl + chitosan as gelling agent was developed . The results showed that through addition of chitosan into gelling agent, the mechanical strength and thermal stability of the carrageenan gel were greatly improved . The new immobilization method was used to entrap a chlorophenol-degrading microorganism . The immobilized microbial cells were applied for chlorophenol biodegradation . The experiments demonstrated that immobilized cells exhibit a higher bioactivity in the degradation of chlorophenol than free cells. FEMS Microbiol Lett, 1999 Apr 15, 173(2), 445 - 52 Fate of phenanthrene, pyrene and benzo{a}pyrene during biodegradation of crude oil added to two soils; Smith MJ et al.; The release of 14CO2 from 9-{14C}phenanthrene, 4,5,9,10-{14C}pyrene and 7-{14C}benzo{a}pyrene, added to Brent/Fortes crude oil and mixed into a pristine sand soil (0.40% organic C) and a pristine organic soil (22.9% organic C), was determined . After 244 days at 25 degrees C, 11.1 +/- 3.5% (sand) and 17.1 +/- 0.30% (organic) phenanthrene-14C and 9.77 +/- 2.8% (sand) and 5.86 +/- 1.4% (organic) benzo{a}pyrene-14C was released . After 210 days, 3.65 +/- 0.5% (sand) and 4.43 +/- 0.33% (organic) pyrene-14C was released . Inoculation of these two soils with DC1 and PD2 (bacteria capable of accelerating the phenanthrene and pyrene mineralisation in soil in the absence of crude oil) either at day 0 or after release as 14CO2 by indigenous degraders had ceased, failed to increase or initiate further mineralisation . Thus, aged PAH residues were non-bioavailable to these metabolically competent degrading microorganisms . At the end of the first period of incubation (210 days or 244 days), the total aromatic hydrocarbons recovered using Soxhlet extraction was 0.18% (sand) and 42.8% (organic) compared with approximately 100% from bio-inhibited soils . This confirmed that the indigenous microbiological activity not only caused a limited amount of PAH mineralisation but also reduced the extractability of residues, possibly due to the generation of metabolites which were chemisorbed and bound (and non extractable) in 'aged' soils. Chirality, 1999, 11(4), 330 - 7 Plant and soil enantioselective biodegradation of racemic phenoxyalkanoic herbicides; Schneiderheinze JM et al.; The biodegradation of the chiral phenoxyalkanoic herbicides 2-(2,4-dichlorophenoxy)propionic aid (2,4-DP) and 2-(4-chloro-2-methylphenoxy)propionic acid (MCPP) was investigated using enantioselective HPLC and chiroptical detection . Racemic mixtures of 2,4-DP and MCPP were applied to three species of turf grass, four species of broadleaf weeds, and soil . Preferential degradation of the S-(-) enantiomer of each herbicide was observed in most species of broadleaf weeds and soil, while the degradation in all species of grass occurred without enantioselectivity . The biodegradation in all systems appeared to follow pseudo first-order kinetics with the fastest degradation occurring in broadleaf weeds, followed by the grasses . The slowest degradation was observed in soil . The results of this work illustrate the need to characterize both enantiomers of chiral agrochemicals in order to have an accurate understanding of their distribution and fate in the environment. Appl Environ Microbiol, 1999 May, 65(5), 2143 - 50 Molecular analysis of microbial community structures in pristine and contaminated aquifers: field and laboratory microcosm experiments; Shi Y et al.; This study used phylogenetic probes in hybridization analysis to (i) determine in situ microbial community structures in regions of a shallow sand aquifer that were oxygen depleted and fuel contaminated (FC) or aerobic and noncontaminated (NC) and (ii) examine alterations in microbial community structures resulting from exposure to toluene and/or electron acceptor supplementation (nitrate) . The latter objective was addressed by using the NC and FC aquifer materials for anaerobic microcosm studies in which phylogenetic probe analysis was complemented by microbial activity assays . Domain probe analysis of the aquifer samples showed that the communities were predominantly Bacteria; Eucarya and Archaea were not detectable . At the phylum and subclass levels, the FC and NC aquifer material had similar relative abundance distributions of 43 to 65% beta- and gamma-Proteobacteria (B+G), 31 to 35% alpha-Proteobacteria (ALF), 15 to 18% sulfate-reducing bacteria, and 5 to 10% high G+C gram positive bacteria . Compared to that of the NC region, the community structure of the FC material differed mainly in an increased abundance of B+G relative to that of ALF . The microcosm communities were like those of the field samples in that they were predominantly Bacteria (83 to 101%) and lacked detectable Archaea but differed in that a small fraction (2 to 8%) of Eucarya was detected regardless of the treatment applied . The latter result was hypothesized to reflect enrichment of anaerobic protozoa . Addition of nitrate and/or toluene stimulated microbial activity in the microcosms, but only supplementation of toluene alone significantly altered community structures . For the NC material, the dominant subclass shifted from B+G to ALF, while in the FC microcosms 55 to 65% of the Bacteria community was no longer identifiable by the phylum or subclass probes used . The latter result suggested that toluene exposure fostered the proliferation of phylotype(s) that were otherwise minor constituents of the FC aquifer community . These studies demonstrated that alterations in aquifer microbial communities resulting from specific anthropogenic perturbances can be inferred from microcosm studies integrating chemical and phylogenetic probe analysis and in the case of hydrocarbon contamination may facilitate the identification of organisms important for in situ biodegradation processes . Further work integrating and coordinating microcosm and field experiments is needed to explore how differences in scale, substrate complexity, and other hydrogeological conditions may affect patterns observed in these systems. Appl Environ Microbiol, 1999 May, 65(5), 1834 - 42 Formation of bound residues during microbial degradation of {14C}anthracene in soil; Kastner M et al.; Carbon partitioning and residue formation during microbial degradation of polycyclic aromatic hydrocarbons (PAH) in soil and soil-compost mixtures were examined by using {14C}anthracenes labeled at different positions . In native soil 43.8% of {9-14C}anthracene was mineralized by the autochthonous microflora and 45.4% was transformed into bound residues within 176 days . Addition of compost increased the metabolism (67.2% of the anthracene was mineralized) and decreased the residue formation (20 . 7% of the anthracene was transformed) . Thus, the higher organic carbon content after compost was added did not increase the level of residue formation . {14C}anthracene labeled at position 1,2,3,4,4a,5a was metabolized more rapidly and resulted in formation of higher levels of residues (28.5%) by the soil-compost mixture than {14C}anthracene radiolabeled at position C-9 (20.7%) . Two phases of residue formation were observed in the experiments . In the first phase the original compound was sequestered in the soil, as indicated by its limited extractability . In the second phase metabolites were incorporated into humic substances after microbial degradation of the PAH (biogenic residue formation) . PAH metabolites undergo oxidative coupling to phenolic compounds to form nonhydrolyzable humic substance-like macromolecules . We found indications that monomeric educts are coupled by C-C- or either bonds . Hydrolyzable ester bonds or sorption of the parent compounds plays a minor role in residue formation . Moreover, experiments performed with 14CO2 revealed that residues may arise from CO2 in the soil in amounts typical for anthracene biodegradation . The extent of residue formation depends on the metabolic capacity of the soil microflora and the characteristics of the soil . The position of the 14C label is another important factor which controls mineralization and residue formation from metabolized compounds. Biomaterials, 1999 Mar, 20(6), 561 - 71 Biodegradation of polysiloxanes in lymph nodes of rats measured with 29Si NMR; Pfleiderer B et al.; Linear and cyclic polysiloxanes and extracts (free polymer) from a silicone gel-filled implant are used to investigate the reactivity of silicones in vivo . Aqueous emulsions of polysiloxanes and controls (without polysiloxanes) are injected once (day 0, approximately 10% w/v) or six times (starting at day 0, every 14 days, approximately 3% w/v) in the right thigh of rats and the popliteal and lumbar lymph nodes are harvested (3 rats per time point and compound investigated) at 2, 16, 30, 44, 58 and 72 days after the injection . 29Si NMR spectroscopy is used to detect and evaluate the presence of polysiloxanes and their metabolites in the lymph nodes . In addition to the resonance associated with the polysiloxane injected (approximately -20 ppm), the NMR spectra of lymph nodes show new resonances that are attributed to partially hydrolyzed polysiloxanes (-5 to -15 ppm) and silica (-90 to - 120 ppm) . These resonances are not present in polysiloxanes emulsions before injection or in the lymph nodes of controls . Our results demonstrate that all polysiloxanes and extracts from silicone gel-filled implants are biotransformed in the lymph nodes, but high molecular weight polymer degrades at a slower rate than oligomers. Chemosphere, 1999 May, 38(11), 2501 - 7 In-vitro study of interaction between photooxidation and biodegradation of 2-methylphenanthrene by Sphingomonas SP . 2MPII; Ni'matuzahroh et al.; This work reports a study of interactions between reactions of photooxidation and reactions of bacterial degradation of an alkylated polyaromatic hydrocarbon (2-methylphenanthrene) . Bacterial growth was carried out using artificial sunlight as light source . Among the various products detected, the major product was identified as the 2-methylphenanthrene aldehyde . Sunlight allows accelerated elimination of the substrate . This enhancement of the biodegradation rate of 2 methylphenanthrene is due to the use of assimilable photoproducts by the bacterium. Chemosphere, 1999 May, 38(11), 2455 - 60 Biodegradation of azo dyes by the yeast Candida zeylanoides in batch aerated cultures; Martins MA et al.; A number of simple azo dyes was degraded in liquid aerated batch cultures by a strain of the yeast Candida zeylanoides . The standard decolorization medium contained glucose as a carbon and energy source, and its pH was either controlled to 5.0-5.2, or allowed to decrease to 3.2-2.8, in the course of microorganism growth . The extent of colour removal in the culture medium was assessed through the decrease in dye absorbance of the supernatants . The extent of colour removal ranged from 44 to 90%, after 7 days, for 5 out of 6 dyes studied in shaked cultures, without pH control, and from 46 to 67%, after 22 hours, for 6 out of 8 dyes in batch experiments, at controlled pH. Lett Appl Microbiol, 1999 Mar, 28(3), 238 - 41 Biodegradation of lindane (gamma-hexachlorocyclohexane) by the white-rot fungus Trametes hirsutus; Singh BK et al.; The ability of the white-rot fungus Trametes hirsutus to degrade an insecticide, lindane, in liquid culture was investigated and compared with that of Phanerochaete chrysosporium . Trametes hirsutus degraded lindane faster than P . chrysosporium but the mechanism of degradation appears to be the same in both . Two metabolites identified in both fungi were tetrachlorocyclohexane and tetrachlorocyclohexanol . The presence of lindane alone inside the mycelium ruled out the involvement of any intracellular enzyme(s) during the initial step of lindane degradation . Lindane at a concentration of 0.27 mumol l-1 exhibited no adverse effect on fungal growth. Biodegradation, 1998, 9(5), 369 - 79 Effect of calcium on the surfactant tolerance of a fluoranthene degrading bacterium; Willumsen PA et al.; Surfactants are known to increase the apparent aqueous solubility of polycyclic aromatic hydrocarbons (PAHs) and may thus be used to enhance the bioavailability and thereby to stimulate the biodegradation of these hydrophobic compounds . However, surfactants may in some cases reduce or inhibit biodegradation because of toxicity to the bacteria . In this study, toxicity of surfactants on Sphingomonas paucimobilis strain EPA505 and the effect on fluoranthene mineralization were investigated using Triton X-100 as model surfactant . The data showed that amendment with 0.48 mM (0.3 g l-1) of Triton X-100 completely inhibited fluoranthene and glucose mineralization and reduced cell culturability by 100% in 24 h . Electron micrographs indicate that Triton X-100 adversely affects the functioning of the cytoplasmic membrane . However, in the presence of 4.13 mM Ca(2+)-ions, Triton X-100 more than doubled the maximum fluoranthene mineralization rate and cell culturability was reduced by only 10% . In liquid cultures divalent ions, Ca2+ in particular and Mg2+ to a lesser extent, were thus shown to be essential for the surfactant-enhanced biodegradation of fluoranthene . Most likely the Ca(2+)-ions stabilized the cell membrane, making the cell less sensitive to Triton X-100 . This is the first report on a specific factor which is important for successful surfactant-enhanced biodegradation of PAHs. Biodegradation, 1998, 9(5), 343 - 57 Microbial degradation of tannins--a current perspective; Bhat TK et al.; Tannins are water-soluble polyphenolic compounds having wide prevalence in plants . Hydrolysable and condensed tannins are the two major classes of tannins . These compounds have a range of effects on various organisms--from toxic effects on animals to growth inhibition of microorganisms . Some microbes are, however, resistant to tannins, and have developed various mechanisms and pathways for tannin degradation in their natural milieu . The microbial degradation of condensed tannins is, however, less than hydrolysable tannins in both aerobic and anaerobic environments . A number of microbes have also been isolated from the gastrointestinal tract of animals, which have the ability to break tannin-protein complexes and degrade tannins, especially hydrolysable tannins . Tannase, a key enzyme in the degradation of hydrolysable tannins, is present in a diverse group of microorganisms, including rumen bacteria . This enzyme is being increasingly used in a number of processes . Presently, there is a need for increased understanding of the biodegradation of condensed tannins, particularly in ruminants. Syst Appl Microbiol, 1999 Feb, 22(1), 113 - 8 Importance of Xanthobacter autotrophicus in toluene biodegradation within a contaminated stream; Tay ST et al.; Toluene-degrading strains T101 and T102 were isolated from rock surface biomass in a toluene-contaminated freshwater stream . These organisms were present at a density of 5.5 x 10(6) cells/g of rock surface biomass . Both are aerobic, rod-shaped, Gram-negative, non-motile, catalase-positive, oxidase-positive, with yellow pigments, and can grow on benzene . Phylogenetic analyses show that strains T101 and T102 have 16S rDNA sequences identical to Xanthobacter autotrophicus . Fatty acid analyses indicate that they are different strains of the same species Xanthobacter autotrophicus, and that they have high levels of cis-11-octadecenoic acid and cis-9-hexadecenoic acid; 3-hydroxyhexadecanoic acid is the major hydroxy fatty acid present . Strains T101 and T102 had maximal velocities (Vmax) for toluene biodegradation of 3.8 +/- 0.5 and 28.3 +/- 2.2 mumoles toluene/mgprotein-hr, and half-saturation constants (Ks) of 0.8 +/- 0.5 and 11.5 +/- 2.4 microM, respectively . Strain T102 has a higher capacity than strain T101 to degrade toluene, and kinetic calculations suggest that strain T102 may be a major contributor to toluene biodegradation in the stream. J Craniomaxillofac Surg, 1999 Feb, 27(1), 42 - 50 SR-PLLA and SR-PGA miniscrews: biodegradation and tissue reactions in the calvarium and dura mater; Peltoniemi HH et al.; The biocompatibility and degradation of self-reinforced poly-L-lactide (SR-PLLA) and polyglycolide (SR-PGA) miniscrews, vs titanium miniscrews, was studied in frontal bone osteotomies in 20 lambs, where they were used for plate fixation . At follow-up at 4, 6, 12, 26, 52 and 104 weeks, no clinical foreign body reaction, infection or other complications had occurred . Histologically, PGA material was hydrolyzed and fragmented at 4-6 weeks and was resorbed by 12 weeks, whereas the SR-PLLA miniscrews retained their integrity and holding power for 26 weeks and were mostly resorbed at 2 years . According to histological and histomorphometric analyses and plain film radiography, the degradation of PGA miniscrews was accompanied by a typical non-specific foreign-body reaction and initial transient osteolysis with decreased osteoid formation around the screw channel, but compensatory intense osteoid formation and bone remodelling followed after resorption of the polymer . The foreign body reactions to PLLA and titanium were considerably milder . All miniscrews were commendably strong and could be satisfactorily tightened against the plate . SR-PLLA miniscrews offer fixation stability for half a year, whereas rapidly degrading SR-PGA miniscrews may be used when short-term fixation is needed. J Appl Biomater, 1990 Fall, 1(3), 241 - 8 Preliminary development of a hydroxyapatite-backed strain gauge; Szivek JA et al.; Long-term in vivo strain sensing would provide information about deformation changes adjacent to implants during bone remodeling . Biodegradation of the cyanoacrylate adhesive commonly used to attach strain gauges to bone has generally limited in vivo strain sensing to time periods less than one month . Hydroxyapatite (HA) which has been used to attach implants to bone in vivo, was attached to strain gauges using a solvent-thinned polysulfone solution . Three HA-polysulfone surface morphologies were tested in a preliminary bench-top test . The single layer pressed surface morphology, which responded most accurately during bench-top testing, was modified slightly and applied to two gauges which were implanted on the femur of a greyhound . Strain measurements from the HA-backed gauges in place for four months in vivo were compared to strains measured from the contralateral femur . Comparison of the results indicated these gauges were well-bonded and that they were sensing strain accurately . After embedding in PMMA, the femur having the HA-backed gauge and the control femur were sectioned at the level of one of the HA-backed gauges . Microradiographs of these sections indicated no adverse tissue response to the HA-backed gauge on the endosteal or periosteal surface. Appl Environ Microbiol, 1999 Apr, 65(4), 1806 - 10 Genetic analysis of biodegradation of tetralin by a Sphingomonas strain; Hernaez MJ et al.; A strain designated TFA which very efficiently utilizes tetralin has been isolated from the Rhine river . The strain has been identified as Sphingomonas macrogoltabidus, based on 16S rDNA sequence similarity . Genetic analysis of tetralin biodegradation has been performed by insertion mutagenesis and by physical analysis and analysis of complementation between the mutants . The genes involved in tetralin utilization are clustered in a region of 9 kb, comprising at least five genes grouped in two divergently transcribed operons. Appl Environ Microbiol, 1999 Apr, 65(4), 1405 - 12 Initial reactions in the biodegradation of 1-chloro-4-nitrobenzene by a newly isolated bacterium, strain LW1; Katsivela E et al.; Bacterial strain LW1, which belongs to the family Comamonadaceae, utilizes 1-chloro-4-nitrobenzene (1C4NB) as a sole source of carbon, nitrogen, and energy . Suspensions of 1C4NB-grown cells removed 1C4NB from culture fluids, and there was a concomitant release of ammonia and chloride . Under anaerobic conditions LW1 transformed 1C4NB into a product which was identified as 2-amino-5-chlorophenol by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry . This transformation indicated that there was partial reduction of the nitro group to the hydroxylamino substituent, followed by Bamberger rearrangement . In the presence of oxygen but in the absence of NAD, fast transformation of 2-amino-5-chlorophenol into a transiently stable yellow product was observed with resting cells and cell extracts . This compound exhibited an absorption maximum at 395 nm and was further converted to a dead-end product with maxima at 226 and 272 nm . The compound formed was subsequently identified by 1H and 13C NMR spectroscopy and mass spectrometry as 5-chloropicolinic acid . In contrast, when NAD was added in the presence of oxygen, only minor amounts of 5-chloropicolinic acid were formed, and a new product, which exhibited an absorption maximum at 306 nm, accumulated. Chemosphere, 1999 Apr, 38(9), 2029 - 39 Measuring the biodegradability of nonylphenol ether carboxylates, octylphenol ether carboxylates, and nonylphenol; Staples CA et al.; We examined the biodegradability of several metabolites of C8- and C9-alkylphenol ethoxylates, including nonylphenoxyacetic acid (NPEC1), nonylphenoxyethoxyacetic acid (NPEC2), octylphenoxyacetic acid (OPEC1), octylphenoxyethoxyacetic acid (OPEC2), and nonylphenol (NP) . Using OECD method 301B (modified Sturm method), OPEC1 and OPEC2 are readily biodegradable: both compounds exceeded 60% of theoretical CO2 formation (ThCO2) by day 28, and required less than 10 days to go from 10% to 60% ThCO2 . Also using method 301B, NPEC1 and NPEC2 exceeded 60% ThCO2 at day 28, but did not meet the 10 day window . Using OECD method 301F, the manometric respirometry method that measures oxygen consumption, approximately 62% of NP was biodegraded in 28 days, but required more than 10 days to go from 10% to 60% biodegradation . While the validity of the "10-day window" is currently being debated within OECD, the data show that the common metabolites of C8- and C9-APEs are rapidly degraded in the test systems used, which strongly suggests that they would not accumulate or persist in the environment. Chemosphere, 1999 Apr, 38(9), 1997 - 2001 An in vitro study on the toxic effects of nonylphenols (NP) in mitochondria; Bragadin M et al.; This paper is focused on alkylphenols, compounds which are formed by the biodegradation of polyethoxilatedalkylphenols detergents . Our experiments show that alkylphenols act not only as detergents, but also as uncouplers of the oxidative phosphorylation . This effect, can be observed at very low doses, thus suggesting that the preferential target of nonylphenols in living organisms are mitochondria. Biotechnol Bioeng, 1999 Jan 5, 62(1), 1 - 11 Kinetics and modeling of autotrophic thiocyanate biodegradation; Hung CH et al.; The biokinetic parameters for autotrophic systems are difficult to obtain and are often mistakenly determined because the size of the autotrophic population in mixed (i.e., heterotrophic and autotrophic) cultures cannot be accurately estimated . This article presents a systematic approach, combining bioenergetic calculations and experimental data, to obtain values of the biokinetic parameters pertinent to the aerobic, autotrophic biodegradation of thiocyanate . Nonlinear regression techniques were employed using both initial thiocyanate utilization rate data and single thiocyanate depletion curves . Both types of data were necessary to overcome the problems arising from the linear nature of the substrate depletion curves and the high correlation of the biokinetic model parameters inherent in nonlinear regression analysis . The aerobic biodegradation of thiocyanate followed a substrate inhibition pattern that was successfully described by the Haldane-Andrews model . Although regression analysis did not yield unique biokinetic parameter estimates, the following parameter value ranges were obtained: maximum specific substrate utilization rate (k), 0.26 to 0.44 mg SCN-/mg biomass h; half-saturation coefficient (Ks), 2.3 to 7.1 mg SCN-/L; and inhibition coefficient (Ki), 28 to 109 mg SCN-/L . Based on the estimated biokinetic parameter values, a design and operation diagram was constructed that depicts the steady-state thiocyanate concentration as a function of solids retention time for a completely mixed, continuous-flow reactor . Biotechnol Bioeng, 1998 Nov 20, 60(4), 397 - 407 Effect of nonionic surfactants on naphthalene dissolution and biodegradation; Mulder H et al.; The effect of six nonionic surfactants, Igepal CA-720, Tergitol NPX, Triton X-100, PLE4, PLE10, and PLE23, on the dissolution rate of solid naphthalene was studied in stirred batch reactors . Results showed increased mass-transfer rates with increased surfactant concentrations up to 10 kg m-3 . Dissolution experiments were adequatly described by a mechanistic mass-transfer model . Partitioning of naphthalene into the micelles and the diffusion coefficients of the micelles affected the dissolution rate most significantly . Combined dissolution and biodegradation experiments with Triton X-100 or PLE10 with naphthalene showed that the biomass-formation rate of Pseudomonas 8909N (DSM No . 11634) increased concomitantly with the mass-transfer rate under naphthalene-dissolution limited conditions up to surfactant concentrations of 6 kg m-3 . Biotechnol Bioeng, 1998 Aug 20, 59(4), 482 - 94 Surfactant-enhanced biodegradation of high molecular weight polycyclic aromatic hydrocarbons by stenotrophomonas maltophilia Boonchan S, Britz ML, Stanley GA. The objectives of this study were to isolate and evaluate microorganisms with the ability to degrade high molecular weight polycyclic aromatic hydrocarbons (PAHs) in the presence of synthetic surfactants . Stenotrophomonas maltophilia VUN 10,010, isolated from PAH-contaminated soil, utilized pyrene as a sole carbon and energy source and also degraded other high molecular weight PAHs containing up to seven benzene rings . Various synthetic surfactants were tested for their ability to improve the PAH degradation rate of strain VUN 10,010 . Anionic and cationic surfactants were highly toxic to this strain, and the Tween series was used as a growth substrate . Five nonionic surfactants (Brij 35, Igepal CA-630, Triton X-100, Tergitol NP-10, and Tyloxapol) were not utilized by, and were less toxic to, strain VUN 10,010 . MSR and log Km values were determined for fluoranthene, pyrene, and benzo{a}pyrene in the presence of these nonionic surfactants and their apparent solubility was increased by a minimum of 250-fold in the presence of 10 g L-1 of all surfactants . The rate of pyrene degradation by strain VUN 10,010 was enhanced by the addition of four of the nonionic surfactants (5-10 g L-1); however, 5 g L-1 Igepal CA-630 inhibited pyrene degradation and microbial growth . The specific growth rate of VUN 10,010 on pyrene was increased by 67% in the presence of 10 g L-1 Brij 35 or Tergitol NP-10 . The addition of Brij 35 and Tergitol NP-10 to media containing a single high molecular weight PAH (four and five benzene rings) as the sole carbon source increased the maximum specific PAH degradation rate and decreased the lag period normally seen for PAH degradation . The addition of Tergitol NP-10 to VUN 10,010 cultures which contained a PAH mixture (three to seven benzene rings) substantially improved the overall degradation rate of each PAH and increased the specific growth rate of VUN 10,010 by 30% . Evaluation of the use of VUN 10,010 for degrading high molecular weight PAHs in leachates from surfactant-flushed, weathered, PAH-contaminated sites is warranted . Biotechnol Bioeng, 1998 Apr 5, 58(1), 1 - 12 Continuous culture dynamics for aniline metabolism by Pseudomonas sp . CIT1; Thomas SM et al.; Inhibition by toxic substrates enables multiple steady states to arise in biodegradation systems . This phenomenon was investigated for the continuous metabolism of aniline by Pseudomonas sp . CIT1 . Differences of various metabolic parameters between the two growth regimes (uninhibited and inhibited) and the transient response to a step-up in dilution rate were determined . Regulatory mechanisms consistent with the experimental evidence are proposed . Aniline is the transcriptional inducer of a metabolic pathway that converts aniline to TCA cycle intermediates . The suite of enzymes is coordinately expressed from a single promoter . We followed the level of the pathway mRNA using a fragment containing the catechol 2,3 dioxygenase gene (andioxB) and monitored the pathway enzyme activity using catechol 2,3 dioxygenase (C23D) . The inhibited regime resulted in a 60% lower growth yield, near constant levels of C23D monomer, but a 50% reduction in the specific activity of C23D, increased RNA synthesis rates (total and aniline pathway mRNA), and elevated RNA decay rates . Elucidation of regulatory mechanisms indicates that C23D is noncompetitively inhibited by aniline and subject to feedback inhibition by 2-hydroxymuconic semialdehyde (HMS) . During uninhibited growth regime operation, metabolism of HMS is the rate-limiting step; in contrast, conversion of aniline to catechol limits growth in the inhibited regime . Biotechnol Bioeng, 1998 Feb 5, 57(3), 356 - 66 Biodegradation kinetics of naphthalene in nonaqueous phase liquid-water mixed batch systems: comparison of model predictions and experimental results; Ghoshal S et al.; A model is formulated to describe dissolution of naphthalene from an insoluble nonaqueous phase liquid (NAPL) and its subsequent biodegradation in the aqueous phase in completely mixed batch reactors . The physicochemical processes of equilibrium partitioning and mass transfer of naphthalene between the NAPL and aqueous phases were incorporated into the model . Biodegradation kinetics were described by Monod's microbial growth kinetic model, modified to account for the inhibitory effects of 1,2-naphthoquinone formed during naphthalene degradation under certain conditions . System parameters and biokinetic coefficients pertinent to the NAPL-water systems were determined either by direct measurement or from nonlinear regression of the naphthalene mineralization profiles obtained from batch reactor tests with two-component NAPLs comprised of naphthalene and heptamethylnonane . The NAPLs contained substantial mass of naphthalene, and naphthalene biodegradation kinetics were evaluated over the time required for near complete depletion of naphthalene from the NAPL . Model predictions of naphthalene mineralization time profiles compared favorably to the general trends observed in the data obtained from laboratory experiments with the two-component NAPL, as well as with two coal tars obtained from the subsurface at contaminated sites and composed of many different PAHs (polycyclic aromatic hydrocarbon compounds) . The effects of varying the NAPL mass and the naphthalene mole fractions in the NAPL are discussed . It was observed that the time to achieve a given percent removal of naphthalene does not change significantly with the initial mass of naphthalene in a fixed volume of the NAPL . Significant changes in the mineralization profiles are observed when the volume (and mass) of NAPL in the system is changed . Biotechnol Bioeng, 1998 Jan 20, 57(2), 145 - 54 Influence of hydrodynamic conditions on naphthalene dissolution and subsequent biodegradation; Mulder H et al.; The influence of hydrodynamic conditions on the dissolution rate of crystalline naphthalene as a model polycyclic aromatic hydrocarbon (PAH) was studied in stirred batch reactors with varying impeller speeds . Mass transfer from naphthalene melts of different surface areas to the aqueous phase was measured and results were modeled according to the film theory . Results were generalized using dimensionless numbers (Reynolds, Schmidt, and Sherwood) . In combined mass transfer and biodegradation experiments, the effect of hydrodynamic conditions on the degradation rate of naphthalene by Pseudomonas 8909N was studied . Experimental results were mathematically described using mass-transfer and microbiological models . The experiments allowed determination of mass-transfer and microbiological parameters separately in a single run . The biomass formation rate under mass transfer limited conditions, which is related to the naphthalene biodegradation rate, was correlated to the dimensionless Reynolds number, indicating increased bioavailability at increased mixing in the reactor liquid . The methodology presented in which mass transfer processes are quantified under sterile conditions followed by a biodegradation experiment can also be adapted to more complex and realistic systems, such as particulate, suspended PAH solids or soils with intrapartically sorbed contaminants when the appropriate mass-transfer equations are incorporated . FEBS Lett, 1999 Mar 5, 446(1), 49 - 54 Biodegradative mechanism of the brown rot basidiomycete Gloeophyllum trabeum: evidence for an extracellular hydroquinone-driven fenton reaction; Kerem Z et al.; We have identified key components of the extracellular oxidative system that the brown rot fungus Gloeophyllum trabeum uses to degrade a recalcitrant polymer, polyethylene glycol, via hydrogen abstraction reactions . G . trabeum produced an extracellular metabolite, 2,5-dimethoxy-1,4-benzoquinone, and reduced it to 2,5-dimethoxyhydroquinone . In the presence of 2,5-dimethoxy-1,4-benzoquinone, the fungus also reduced extracellular Fe3+ to Fe2+ and produced extracellular H2O2 . Fe3+ reduction and H2O2 formation both resulted from a direct, non-enzymatic reaction between 2,5-dimethoxyhydroquinone and Fe3+ . Polyethylene glycol depolymerization by G . trabeum required both 2,5-dimethoxy-1,4-benzoquinone and Fe3+ and was completely inhibited by catalase . These results provide evidence that G . trabeum uses a hydroquinone-driven Fenton reaction to cleave polyethylene glycol . We propose that similar reactions account for the ability of G . trabeum to attack lignocellulose. Semin Vasc Surg, 1999 Mar, 12(1), 83 - 91 Structural failure of Dacron arterial grafts; Nunn DB; The ultimate test of a Dacron (polyethylene terephthalate or PET) arterial prosthesis depends on its ability to retain sufficient strength and durability to function properly for the life of the patient . Because graft recipients appear to be living longer, primarily because of improved medical and surgical treatment o