Waste Manag Res, 2003 Apr, 21(2), 119 - 26 Modelling simplification of landfill processes by using methods of reliability theory; Hosser D et al.; By the year 2005 most landfills in Germany will be closed down and begin the closing phase and later the after-care phase . So far there have been only a few scientific investigations concerning the hazard potential of stored waste for the environment . For this reason, it is necessary to predict how the hazard potential of landfills will vary after closure . The prediction can be made by describing the coupled processes of biodegradation and pollutant transport using models that are currently being developed . These models deal with highly non-linear differential equations having a large number of parameters . In order to permit application of the model in practice, it is necessary to reduce these to parameters which are essential to the reliability of the landfill . They have to be identified by sensitivity investigations with the aid of methods of reliability theory so that models can be limited to these essential parameters and the calculation effort as well as measurement of parameters (monitoring) can be considerably reduced. Chemosphere, 2003 Jul, 52(4), 673 - 82 Biodegradation of phthalate esters during the mesophilic anaerobic digestion of sludge; Gavala HN et al.; Phthalic acid esters (PAE) are commonly found in the sludge generated in the wastewater treatment plants . Anaerobic digestion followed by land application is a common treatment and disposal practice of sludge . To date, many studies exist on the anaerobic biodegradation rates of PAE, especially of the easily biodegradable ones, whereas the higher molecular weight PAE have reported to be non-biodegradable under methanogenic conditions . Furthermore, there is no information on the effect of the PAE on the performance of the anaerobic digesters treating sludge . In this study, the anaerobic biodegradation of di-n-butyl phthalate (DBP), di-ethyl phthalate (DEP) and di-ethylhexyl phthalate (DEHP) was investigated and their relative rates of anaerobic degradation were calculated . Also, the biological removal of PAE during the anaerobic digestion of sludge in bench-scale digesters was investigated using DBP and DEHP as model compounds of one biodegradable and one recalcitrant PAE respectively . The degradation of all the PAE tested in this study (DEP, DBP and DEHP) is adequately described by first-order kinetics . Batch and continuous experiments showed that DEP and DBP present in sludge are rapidly degraded under mesophilic anaerobic conditions (a first-order kinetic constant of 8.04 x 10(-2) and 13.69 x 10(-2)-4.35 day(-1) respectively) while DEHP is degraded at a rate between one to two orders of magnitude lower (0.35 x 10(-2)-3.59 x 10(-2) day(-1)) . It is of high significance that experiments with anaerobic sludge of different origin (US and Europe) showed that degradation of DEHP occurs under methanogenic conditions . Accumulation of high levels of DEHP (more than 60 mg/l) in the anaerobic digester has a negative effect on DBP and DEHP removal rates as well as on the biogas production. Chemosphere, 2003 Jul, 52(2), 437 - 42 Uptake, translocation and fate of trichloroacetic acid in a Norway spruce/soil system; Schroder P et al.; Trichloroacetic acid (TCA) is a secondary atmospheric pollutant formed by photooxidation of chlorinated solvents in the troposphere--it has, however, recently been ranked among natural organohalogens . Its herbicidal properties might be one of the factors adversely affecting forest health . TCA accumulates rapidly in conifer needles and influences the detoxification capacity in the trees . The aim of the investigations--a survey of which is briefly given here--was to elucidate the uptake, distribution and fate of TCA in Norway spruce . For this purpose young nursery-grown plants of Norway spruce (Picea abies (L.) Karst.) were exposed to {1,2-14C}TCA and the fate of the compound was followed in needles, wood, roots, soil and air with appropriate radio-indicator methods . As shown by radioactivity monitoring, the uptake of TCA from soil by roots proceeded most rapidly into current needles at the beginning of the TCA treatment and was redistributed at later dates so that TCA content in older needles increased . The only product of TCA metabolism/biodegradation found in the plant/soil-system was CO(2) (and corresponding assimilates) . TCA biodegradation in soil depends on TCA concentration, soil humidity and other factors. J Biomed Mater Res A, 2003 May 1, 65(2), 170 - 81 Coaxial double-tubular compliant arterial graft prosthesis: time-dependent morphogenesis and compliance changes after implantation; Sonoda H et al.; In order to reduce the compliance mismatch between the native artery and the artificial graft, we have developed a coaxial double-tubular compliant graft, using multiply micropored segmented polyurethane (SPU) thin films, which mimics the relationship between the intraluminal pressure and vessel internal diameter (P-D) of the native artery (termed "J" curve) . The graft was coaxially assembled by inserting a high-compliance inner tube with a heparin-immobilized photocured gelatin coating layer into a low-compliance outer tube with a photocured hydrophilic polymer coating layer . Twenty-eight coaxial double-tubular compliant grafts were implanted into the canine common carotid arteries in an end-to-end fashion for up to 12 months . The overall patency rate was 86% (24/28), and neither rupture nor aneurysmal formation was observed . A neoarterial wall was formed via transanastomotic and transmural tissue ingrowth, resulting in neoarterial tissue formation on the luminal surface and into the intertubular space of the double-tubular graft, accompanied by mainly myofibroblasts and inflammatory cells in the early stage and endothelialization and collagen-rich extracellular matrices in the late stage of implantation . Surrounding-tissue adhesion with the outer tube was prevented by the hydrophilic polymer coating . Although the J curve of the implanted prototype model was preserved 1 month after implantation, the impaired J curves were observed because of tissue ingrowth and tissue adhesion between the outer surface of the inner tube and the surrounding tissues 3 and 6 months after implantation . At 12 months after implantation, however, the implanted coaxial double-tubular graft exhibited high compliance due to biodegradation of the SPU films . Bioresour Technol, 2003 Mar, 87(1), 81 - 6 Biodegradation of hexadecane in liquid and solid-state fermentations by Aspergillus niger; Volke-Sepulveda TL et al.; The biodegradation and mineralisation of hexadecane (HXD) by Aspergillus niger were studied in SmF and Solid-state fermentation (SSF) . HXD concentrations ranging from 45 to 180 g/l (SSF) and from 20 to 80 g/l (SmF) were tested . HXD consumption was three times higher and fungal growth was up to 30 times faster in SSF than in SmF . The maximum HXD consumption in SmF was 62% (18% mineralised) and in SSF 100% (52% mineralised) for initial HXD concentrations of 20 and 45 g/l, respectively . The respiratory quotient in SmF increased (from 0.85 to 1.08) with increase in HXD concentration, while it was independent (approximately 0.68) of the initial HXD concentration in SSF . These results showed that the consumption rate and biodegradation efficiency for HXD were higher in SSF than in SmF. Curr Microbiol, 2003 May, 46(5), 371 - 9 Function of a low molecular weight peptide from Trichoderma pseudokoningii S38 during cellulose biodegradation; Wang W et al.; The biochemical mechanism for cellulose decomposition by a low molecular weight peptide, named short fiber generating factor (SFGF), derived from the culture supernatant of a cellulolytic fungus Trichoderma pseudokoningii S-38, was determined . Sufficient information obtained by biochemical and biophysical studies and combined with observation with a scanning electron microscope provided further evidence for the earlier studies that the SFGF had a high capacity for chelating and reducing ferric ions, and could produce free radical by reduction of Fe(3+) to Fe(2+) in the presence of oxygen molecule . These studies suggested that the effect of SFGF on cellulose is directly related to an oxidative reaction and is different from the hydrolysis of cellulose by cellulases . The alcoholic hydroxyl groups in cellulose can be oxidized by SFGF, which leads to destruction of the hydrogen bond network in cellulose and cleavage of glycosidic linkages . Both effects led to the de-polymerization of cellulose and the formation of short fibers, and increase of reducing groups in residual cellulose, then the cellulose substrates became more susceptible for hydrolysis by cellulases. Environ Sci Technol, 2003 Apr 15, 37(8), 1545 - 52 Intra-aggregate mass transport-limited bioavailability of polycyclic aromatic hydrocarbons to Mycobacterium strain PC01; Shor LM et al.; Biodegradation kinetics for three- and four-ring PAHs by Mycobacterium sp . strain PC01 were measured in whole and density-fractionated estuarine sediments and in a system without intra-aggregate mass transport limitations . The biokinetic data in the systems with and without intra-aggregate mass transport limitations were compared with abiotic PAH desorption kinetics . The results indicate that intra-aggregate mass transport limitations, and not the intrinsic bacterial PAH utilization capacity, were most important in controlling the rate of biodegradation of sediment-sorbed PAHs . Achievable extent of biodegradation could be predicted by the independently measured traction of desorbable PAHs in the fast-diffusion regime of a two-domain intra-aggregate mass transport model . A closed-form mathematical model was developed to describe sediment-pore water partitioning and rapid aqueous-phase diffusion of PAHs through the macropore and mesopore network of sediment aggregates, followed by first-order biodegradation of desorbed PAHs in the bulk aqueous domain . The model effectively predicted independent biodegradation kinetics of PAHs field-aged in two estuarine sediments . Despite low aqueous solubility of PAHs, macropore and mesopore diffusion may be an important mechanism controlling intra-aggregate mass transport and bioavailability of the most readily and extensively desorbed PAHs in sediments. Biosci Biotechnol Biochem, 2003 Feb, 67(2), 225 - 43 Genetics of polycyclic aromatic hydrocarbon metabolism in diverse aerobic bacteria; Habe H et al.; Polycyclic aromatic hydrocarbons (PAHs), which consist of two or more fused aromatic rings, are widespread in the environment and persist over long periods of time . The decontamination of a PAH-polluted environment is of importance because some PAHs are toxic, mutagenic, and carcinogenic and therefore are health hazards . As part of the efforts to establish remediation processes, the use of aerobic bacteria has been extensively studied, and both enzymologic and genetic studies are underway for the purpose of effective biodegradation . In the last two decades, one highly conserved group of PAH-catabolic genes from Pseudomonas species, called the nah-like genes, has been well investigated, and much has been found, including the structure-function relationships and the evolutionary trails of the catabolic enzymes . However, recently, PAH-catabolic genes, which are evolutionarily different from the nah-like genes, have been characterized from both Gram-negative bacteria other than Pseudomonas species and Gram-positive bacteria, and the information about these genes is expanding . This review is an outline of genetic knowledge about bacterial PAH catabolism. Biodegradation, 2002, 13(6), 395 - 9 Biodegradation of glucosinolates in brown mustard seed meal (Brassica juncea) by Aspergillus sp . NR-4201 in liquid and solid-state cultures; Rakariyatham N et al.; Aspergillus sp . NR-4201 was assessed by degrading glucosinolates in brown mustard seed meal (Brassica juncea) . A liquid culture of the strain, in a medium derived from the meal, produced total degradation of glucosinolates at 32 h . Under these conditions, the glucosinolate-breakdown product, allylcyanide, was formed in culture filtrates . In a plate culture under sterile conditions, the growth of the strain in heat-treated meal media was shown to be effective at 30 degrees C with 51% moisture, as determined by the measurement of the colony growth rate . On the laboratory scale, solid-state culture under the same conditions gave rise to total glucosinolate degradation within 48 h . In comparison, under non-sterile conditions in either heat-treated or non heat-treated meal samples, the degradations were complete after 60 and 96 h, respectively . In these cases, growth was associated with some out-growths of contaminating fungi, mainly Rhizopus sp . and Mucor sp . The glucosinolate-breakdown product, allylcyanide, was not detected in the solid-state meal-media culture presumably due to evaporative loss from the fermentation matrix. Biomaterials, 2003 Jul, 24(16), 2779 - 87 Bio-compatibility of type I/III collagen matrix for peripheral nerve reconstruction; Keilhoff G et al.; Nerve gaps are usually bridged by autografts . With improving technical methods biocompatible conduits may become an alternative graft to reconstruct nerves . Non-neural conduits fail to support regeneration over larger gaps due to lacking viable Schwann cells . Thus, tissue engineering of nerves is focusing on implantation of viable Schwann cells into suitable scaffolds . In this study, we tested collagen type I/III tubes as a potential nerve guiding matrix . Revascularization, foreign body reaction, biodegradation and Schwann cell settlement were evaluated by immunocytochemistry, light, fluorescence and scanning electron microscopy, after different implantation times . The conduits were completely revascularized between day 5 and 7 post-operatively and well integrated into the host tissue . Host response was characterized by a moderate invasion of ED1/ED2-positive macrophages . Biodegradation of the tubes was slowly enough to maintain a stable support structure for extended regeneration processes . Implanted Schwann cells adhered, survived and proliferated on the inner surface of the conduits and were able to form nerve guiding columns of Bungner . From this results, we conclude that collagen-type I/III can serve as template to design "living" nerve conduits, which may be able to ensure nerve regeneration through extended nerve gaps. Biomaterials, 2003 Jul, 24(16), 2773 - 8 Thermal and mechanical characteristics of poly(L-lactic acid) nanocomposite scaffold; Lee JH et al.; Inorganic nanosized silicate nanoplatelets were incorporated into biodegradable poly(L-lactic acid) (PLLA) for the purpose of tailoring mechanical stiffness of PLLA porous scaffold systems . Increasing the nucleation density around the foreign body surfaces, the montmorillonite (MMT) nanoplatelets modified with dimethyl dihydrogenated tallow ammonium cations decreased the glass transition temperature and the degree of PLLA crystallinity, which seemingly caused the accelerated biodegradation rate of PLLA nanocomposites due to the enhanced segmental mobility of backbone chains and the expanded amorphous region of PLLA matrix . The tensile modulus was increased from 121.2MPa of pristine polymer scaffold to 170.1MPa of MMT/PLLA nanocomposite scaffold (ca . 40% increment) by the addition of small amount of MMT platelets (5.79 vol%) acting as a mechanical reinforcement of polymer chains in the nanoscale molecular level . Overall, the nanotechnology used in this study may be applied to various scaffold systems of biodegradable polymers and hard/soft scaffold structures requiring critical control and design characteristics of mechanical stiffness and biodegradation rate. Environ Int, 2003 Jul, 29(4), 459 - 65 Aerobic degradation of 2,4,6-TCP content in ECF bleached effluent; Correa J et al.; Elemental chlorine-free (ECF) bleach effluents from kraft mill are characterised by: a chemical organic demand/biological organic demand (COD/BOD(5)) ratio of 4, chlorophenol content with low chlorine substitution, and toxicity . The effect of increasing the concentration of 2,4,6-trichlorophenol (2,4,6-TCP) content in ECF bleaching sequence effluent on the degradative activity of bacterial communities present in an aerobic system treatment was studied . An aerobic lagoon (AL) was used as a typical secondary treatment of kraft-mill effluent . AL displays a high performance of BOD(5) degradation (up to 90%); however, only 40% of the COD was removed . Simultaneously, the AL system shows a high ability to biodegrade 2,4,6-TCP up to 237 mg/l day . Kinetic parameters of the 2,4,6-TCP biodegradation by aerobic bacteria were determined . The K(s) and K(i) values were 34.3 and 50 mg/l 2,4,6-TCP, respectively . Moreover, the tolerance of aerobic bacteria was observed up to 1.3 g/l 2,4,6-TCP. Mar Pollut Bull, 2003 Apr, 46(4), 418 - 23 Biodegradation of toxic chemicals in Guayanilla Bay, Puerto Rico; Zaidi BR et al.; Studies were conducted to assess the factors that may influence the rate and extent of biodegradation of biphenyl, naphthalene, phenanthrene, pentachlorophenol (PCP) and p-nitrophenol in water samples collected from the Guayanilla Bay (18 degrees N; 67.45 degrees W), southwest of Puerto Rico . In vitro studies mediated slow degradation of biphenyl, naphthalene and phenanthrene substrates by natural microbial flora present in the Bay . Addition of KNO(3) as a source of inorganic N greatly enhanced the degradation of phenanthrene but not of naphthalene, suggesting that effects on degradation due to nutrient limitation were compound specific . The rate and extent of degradation of naphthalene and PCP were higher in water samples collected closer to the source of contamination, i.e . the petrochemical complex . The identity of a phenanthrene degrading bacterium, previously identified by conventional phenotypic method (Zaidi et al., Utilizing Nature's Advanced Materials, Oxford Unviersity Press, 1999) as Alteromonas sp., was confirmed by partial DNA sequencing of the small subunit rRNA gene. Biomaterials, 2003 Jun, 24(13), 2309 - 16 Cell sheet engineering for myocardial tissue reconstruction; Shimizu T et al.; Myocardial tissue engineering has now emerged as one of the most promising treatments for the patients suffering from severe heart failure . Tissue engineering has currently been based on the technology using three-dimensional (3-D) biodegradable scaffolds as alternatives for extracellular matrix . According to this most popular technique, several types of 3-D myocardial tissues have been successfully engineered by seeding cardiomyocytes into poly(glycolic acid), gelatin, alginate or collagen scaffolds . However, insufficient cell migration into the scaffolds and inflammatory reaction due to scaffold biodegradation remain problems to be solved . In contrast to these technologies, we now propose novel tissue engineering methodology layering cell sheets to construct 3-D functional tissues without any artificial scaffolds . Confluent cells on temperature-responsive culture surfaces can be harvested as a viable contiguous cell sheet only by lowering temperature without any enzymatic digestions . Electrical communications are established between layered cardiomyocyte sheets, resulting in simultaneous beating 3-D myocardial tissues . Layered cardiomyocyte sheets in vivo present long survival, macroscopic pulsation and characteristic structures of native heart tissue . Cell sheet engineering should have enormous potential for fabricating clinically applicable myocardial tissues and should promote tissue engineering research fields. Water Res, 2003 Apr, 37(8), 1729 - 36 Effect of non-aqueous phase liquid on biodegradation of PAHs in spilled oil on tidal flat; Kose T et al.; Biodegradation rates of polycyclic aromatic hydrocarbons (PAHs) in spilled oil stranded on tidal flats were evaluated using model reactors to clarify the effects of non-aqueous phase liquid (NAPL) on the biodegradation of PAHs in stranded oil on tidal flat with special emphasis on the relationship between dissolution rates of PAHs into water and viscosity of NAPL . Biodegradation of PAHs in NAPL was limited by the dissolution rates of PAHs into water . Biodegradation rate of chrysene was smaller than that of acenaphtene and phenanthrene due to the smaller dissolution rates . Dissolution rates of PAHs in fuel oil C were smaller than those in crude oil due to high viscosity of fuel oil C . Hence, biodegradation rates of PAHs in fuel oil C were smaller than those in crude oil . Biodegradation rates of PAHs in NAPL with slow rate of decrease like fuel oil C was slower than those in NAPL with rapid rate of decrease like crude oil . The smaller rate of decrease of fuel oil C than crude oil was due to the higher viscosity of fuel oil C . Therefore, not only the dissolution rate of PAHs but also the rates of decrease of NAPL were important factors for the biodegradation of PAHs. Biomaterials, 2003 Jun, 24(14), 2549 - 57 In vivo biostability of a poly(carbonate-urea)urethane graft; Seifalian AM et al.; In peripheral and coronary bypass surgery, the patency of prosthetic grafts is inferior to autologous vein, mainly due to intimal hyperplasia caused in part by compliance mismatch between rigid graft and elastic host artery . We have developed a compliant poly(carbonate-urea)urethane vascular graft "MyoLink" which was biostable in vitro degradation studies . To further investigate the biostability of this material, we report a long-term in vivo study on 8 beagle dogs (15+/-3 kg) implanted with this graft (ID 5mm) in the aorta-iliac position; three grafts were harvested at 18 months to assess short-term biodegradation, with one animal having died from an unrelated infection . The 4 remaining grafts were harvested at 36 months for analysis by: (1) histology, (2) compliance measurements and (3) environmental scanning electron microscopy (ESEM); gel permeation chromatography (GPC); attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and radial tensile strength analysis.There was no infection or inflammation of the grafts or surrounding tissues . Histological analysis showed a well-developed neointima but only at the distal anastomosis . There were no significant differences in compliance pre- and post-implantation and no evidence of material curvature, radial expansion or chemical breakdown, ESEM and GPC showed no signs of degradation . Peak height analysis with ATR-FTIR of the 1740 cm(-1) (C=O of carbonate) and 1253 cm(-1) bands (C-O-C of CO-O-C) showed a loss of carbonate carbonyl but was not statistically significant . Radial tensile strength remained within batch release specifications.This polyurethane graft retains its compliance post-implantation, whilst exhibiting only a minor hydrolysis of the amorphous segment, confirming its biostability in vivo up to 3 years. Biomaterials, 2003 Jun, 24(14), 2497 - 502 A biodegradable fibrin scaffold for mesenchymal stem cell transplantation; Bensaid W et al.; A potential therapy to enhance healing of bone tissue is to deliver isolated mesenchymal stem cells (MSCs) to the site of a lesion to promote bone formation . A key issue within this technology is the development of an injectable system for the delivery of MSCs . Fibrin gel exploits the final stage of the coagulation cascade in which fibrinogen molecules are cleaved by thrombin, convert into fibrin monomers and assembled into fibrils, eventually forming fibers in a three-dimensional network . This gel could have many advantages as a cell delivery vehicle in terms of biocompatibility, biodegradation and hemostasis . The objective of this study was to explore the possibility of using fibrin gel as a delivery system for human MSCs (HMSCs) . To this end we have determined the optimal fibrinogen concentrations and thrombin activity for loading HMSCs in vitro into the resultant fibrin gels to obtain cell proliferation . We found that a concentration of 18 mg/ml of fibrinogen and a thrombin activity of 100 IU/ml was optimal for producing fibrin scaffolds that would allow good HMSCs spreading and proliferation . In these conditions, cells were able to proliferate and expressed alkaline phosphatase, a bone marker, in vitro . When implanted in vivo, HMSCs were able to migrate out of the fibrin gel and invade a calcium carbonate based ceramic scaffold suggesting that fibrin gel could serve as a delivery system for HMSCs. FEMS Microbiol Lett, 2003 Apr 11, 221(1), 111 - 7 Isolation and characterisation of Nocardioides sp . SP12, an atrazine-degrading bacterial strain possessing the gene trzN from bulk- and maize rhizosphere soil; Piutti S et al.; We report the characterisation of Nocardioides sp . SP12, an atrazine-degrading bacteria isolated from atrazine-treated bulk- and maize rhizosphere soil . Based on 16S rDNA alignment, strain SP12 showed close phylogenic relationships with Nocardioides sp . C157 and Nocardioides simplex . Internal transcribed spacer (ITS) sequences of strain SP12 were longer than those of other Nocardioides sp . and present Ala- and Ile-tRNA unlike Actinomycetales . Nocardioides sp . SP12 presents a novel atrazine catabolic pathway combining trzN with atzB and atzC . Atrazine biodegradation ends in a metabolite that co-eluted in HPLC with cyanuric acid . This metabolite shows an absorption spectrum identical to that of cyanuric acid with a maximal absorption at 214.6 nm . The mass of the atrazine metabolite is in concordance with that of cyanuric acid according to mass spectrometry analysis . Quantitative PCR revealed that the ITS sequence of Nocardioides sp . SP12 was at a lower number than the one of trzN in atrazine-treated soil samples . It suggests that trzN could also be present in other atrazine degrading bacteria . The numbers of trzN and ITS sequences of Nocardioides sp . SP12 were higher in the maize rhizosphere than in bulk soil. Water Res, 2003 May, 37(9), 2149 - 61 Source apportionment of PAHs in dated sediments from the Black River, Ohio; Gu SH et al.; Black River, OH, is contaminated with polycyclic aromatic hydrocarbons (PAHs) from coke ovens of a US Steel Corp . Plant . Closing of a coking plant in 1983 and environmental dredging of the sediments during 1989 and 1990 has reduced the PAH levels significantly . This study quantifies the decrease, and consider source apportionment of PAHs in Black River sediments using chemical mass balance modeling . Five vibra cores collected in 1998 and dated using 210Pb and 137Cs, were analyzed for 18 PAHs . The cores had total PAH concentrations between 250 and 0.10 ppm . PAH maxima occur in 1949, 1969, in accordance with regional historical inputs (core BR4), and in 1991 due to remediation (BR6) . Coke oven emissions (CO), highway dust (HWY), and wood burning (WB) are likely sources . The CO source (6-92% of total PAHs) is maximal in 1954, and again in 1992-1994 due to the exposure and redistribution of older contaminated sediments during dredging, and decreases thereafter . There is minimal CO content in 1985 (BR4), 2 yr after closure of the coking plant . The HWY contribution (2-86%) is high during 1969-1988, and increases again after 1993 . The WB source is less than 23%, and exhibits a minimum (2%) around 1979 (BR4) . There is evidence of aerobic biodegradation or photolysis in the sediment of phenanthrene (PhA) at PhA concentrations >500 ppb. Biodegradation, 2002, 13(5), 297 - 305 Mechanism of aerobic transformation of carbon tetrachloride by poplar cells; Wang X et al.; The biochemical mechanism of carbon tetrachloride transformation by poplar cells was investigated using an axenic poplar cell culture . After one-day incubations of poplar cells under aerobic conditions, about 1.5% of dosed carbon tetrachloride was transformed to carbon dioxide, about 0.001% to chloroform and about 3% of the carbon was bound to insoluble poplar cellular materials . The production of carbon dioxide increased under aerobic conditions while the formation of chloroform and cell binding of carbon tetrachloride-carbon was enhanced under anaerobic conditions . Both carbon dioxide production and cell binding were significantly inhibited by a general inhibitor of cytochrome P-450 activity (carbon monoxide) and by specific P-450 2E1 inhibitors (chlorzoxazone, isoniazid, 4-methylpyrazole and 1-phenylimidazole) . However, no inhibitory effects were observed when the cells were incubated in the presence of lignin peroxidase inhibitors (NaVO3 and 3-amino-1,2,4-triazole) . These results suggest that an enzyme similar to mammalian cytochrome P450-2E1 is involved in the metabolism of carbon tetrachloride by poplar cells . This study demonstrates an environmental biodegradative process for carbon tetrachloride that operates under aerobic conditions. Environ Sci Technol, 2003 Mar 15, 37(6), 1061 - 8 Occurrence and fate of carbamazepine, clofibric acid, diclofenac, ibuprofen, ketoprofen, and naproxen in surface waters; Tixier C et al.; Although various single-concentration measurements of pharmaceuticals are available in the literature, detailed information on the variation over time of the concentration and the load in wastewater effluents and rivers and on the fate of these compounds in the aquatic environment are lacking . We measured the concentrations of six pharmaceuticals, carbamazepine, clofibric acid, diclofenac, ibuprofen, ketoprofen, and naproxen, in the effluents of three wastewater treatment plants (WWTPs), in two rivers and in the water column of Lake Greifensee (Switzerland) over a time period of three months . In WWTP effluents, the concentrations reached 0.95 microg/L for carbamazepine, 0.06 microg/L for clofibric acid, 0.99 microg/L for diclofenac, 1.3 microg/L for ibuprofen, 0.18 microg/L for ketoprofen, and 2.6 microg/L for naproxen . The relative importance in terms of loads was carbamazepine, followed by diclofenac, naproxen, ibuprofen, clofibric acid, and ketoprofen . An overall removal rate of all these pharmaceuticals was estimated in surface waters, under real-world conditions (in a lake), using field measurements and modeling . Carbamazepine and clofibric acid were fairly persistent . Phototransformation was identified as the main elimination process of diclofenac in the lake water during the study period . With a relatively high sorption coefficient to particles, ibuprofen might be eliminated by sedimentation . For ketoprofen and naproxen, biodegradation and phototransformation might be elimination processes . For the first time, quantitative data regarding removal rates were determined in surface waters under real-world conditions . All these findings are important data for a risk assessment of these compounds in surface waters. Microbiology, 2003 Apr, 149(Pt 4), 903 - 13 Rational engineering of the regioselectivity of TecA tetrachlorobenzene dioxygenase for the transformation of chlorinated toluenes; Pollmann K et al.; The tetrachlorobenzene dioxygenase (TecA) of Ralstonia sp . PS12 carries out the first step in the aerobic biodegradation of chlorinated toluenes . Besides dioxygenation of the aromatic ring of 4-chloro-, 2,4-, 2,5- and 3,4-dichlorotoluene as the main reaction, it also catalyses mono-oxygenation of the methyl groups of 2,3-, 2,6-, 3,5-di- and 2,4,5-trichlorotoluene as the main reactions, channelling these compounds into dead-end pathways . Based on the crystal structure of the homologous naphthalene dioxygenase (NDO) and alignment of the alpha-subunits of NDO and TecA, the substrate pocket of TecA was modelled . Recently, for NDO and the homologous 2-nitrotoluene dioxygenase (2NTDO), two amino acids (Phe(352) of NDO and Asn(258) of 2NTDO) were identified which control the regioselectivity of these enzymes . The corresponding amino acids at Phe(366) and Leu(272) of TecA were substituted to change the regioselectivity and to expand the product spectrum . Position 366 was shown to control regioselectivity of the enzyme, although mutations resulted in decreased or lost activity . Amino acid substitutions at Leu(272) had little or no effect on the regioselectivity of TecA, but had significant effects on the product formation rate . Substitutions at both positions changed the site of oxidation of 2,4,5-trichlorotoluene slightly . As new products, 3,4,6-trichloro-1-methyl-1,2-dihydroxy-1,2-dihydrocyclohexan-3,5-diene, 4,6-dichloro-3-methylcatechol, 3,6-dichloro-4-methylcatechol and 3,4-dichloro-6-methylcatechol were identified. Environ Toxicol Chem, 2003 Apr, 22(4), 837 - 44 Predicting ready biodegradability of premanufacture notice chemicals; Boethling RS et al.; Chemical substances other than pesticides, drugs, and food additives are regulated by the U.S . Environmental Protection Agency (U.S . EPA) under the Toxic Substances Control Act (TSCA), but the United States does not require that new substances be tested automatically for such critical properties as biodegradability . The resulting lack of submitted data has fostered the development of estimation methods, and the BioWIN models for predicting biodegradability from chemical structure have played a prominent role in premanufacture notice (PMN) review . Until now, validation efforts have used only the Japanese Ministry of International Trade and Industry (MITI) test data and have not included all models . To assess BioWIN performance with PMN substances, we assembled a database of PMNs for which ready biodegradation data had been submitted over the period 1995 through 2001 . The 305 PMN structures are highly varied and pose major challenges to chemical property estimation . Despite the variability of ready biodegradation tests, the use of at least six different test methods, and widely varying quality of submitted data, accuracy of four of six BioWIN models (MITI linear, MITI nonlinear, survey ultimate, survey primary) was in the 80+% range for predicting ready biodegradability . Greater accuracy (>90%) can be achieved by using model estimates only when the four models agree (true for 3/4 of the PMNs) . The BioWIN linear and nonlinear probability models did not perform as well even when classification criteria were optimized . The results suggest that the MITI and survey BioWIN models are suitable for use in screening-level applications. Environ Toxicol Chem, 2003 Apr, 22(4), 699 - 705 Enhancement of aerobic microbial degradation of polychlorinated biphenyl in soil microcosms; Manzano MA et al.; This article reports the results of various biodegradation experiments on polychlorinated biphenyl (PCB)-contaminated sandy soil employing a mixed culture of acclimatized bacteria . Following the optimization of different variables without chemical pretreatment, the elimination rate achieved of Aroclor 1242 in slurry-phase reactors was 61% after four months of treatment, with the presence of biphenyl as cosubstrate being the most important factor affecting PCB biodegradation . The biodegradation occurred as a first-order process, and it proved most effective in respect to dichlorinated biphenyls (100% removal), followed by trichlorinated (92%) and tetrachlorinated biphenyls (24%) . The results also showed that the degradability of PCBs in soil may be enhanced by an advanced oxidation pretreatment (Fenton reaction), producing almost 100% elimination of PCBs at the end of the integrated chemical-biological process and 72% mineralization of the intermediates generated during the chemical pretreatment. J Contam Hydrol, 2002 Nov, 59(1-2), 133 - 62 A case study for demonstrating the application of U.S . EPA's monitored natural attenuation screening protocol at a hazardous waste site; Clement TP et al.; Natural attenuation assessment data, collected at a Superfund site located in Louisiana, USA, are presented . The study site is contaminated with large quantities of DNAPL waste products . Source characterization data indicated that chlorinated ethene and ethane compounds are the major contaminants of concern . This case study illustrates the steps involved in implementing the U.S . EPA's {U.S . EPA, 1998 . Technical protocol for evaluating natural attenuation of chlorinated solvents in ground water, by Wiedmeier, T.H., Swnason, M.A., Moutoux, D.E., Gordon, E.K., Wilson, J.T., Wilson, B.H., Kampbell, D.H., Hass, P.E., Miller, R.N., Hansen, J . E., Chapelle, F.H., Office of Research and Development, EPA/600/R-98/128} monitored natural attenuation (MNA) screening protocol at this chlorinated solvent site . In the first stage of the MNA assessment process, the field data collected from four monitoring wells located in different parts of the plume were used to complete a biodegradation scoring analysis recommended by the protocol . The analysis indicates that the site has the potential for natural attenuation . In the second stage, a detailed conceptual model was developed to identify various contaminant transport pathways and exposure points . The U.S . EPA model and BIOCHLOR was used to assess whether the contaminants are attenuating at a reasonable rate along these transport paths so that MNA can be considered as a feasible remedial option for the site . The site data along with the modeling results indicate that the chlorinated ethene and chlorinated ethane plumes are degrading and will attenuate within 1000 ft down gradient from the source, well before reaching the identified exposure point Therefore, MNA can be considered as one of the feasible remediation options for the site. J Contam Hydrol, 2002 Nov, 59(1-2), 113 - 31 Modelling of physical and reactive processes during biodegradation of a hydrocarbon plume under transient groundwater flow conditions; Prommer H et al.; Numerical experiments of non-reactive and reactive transport were carried out to quantify the influence of a seasonally varying, transient flow field on transport and natural attenuation at a hydrocarbon-contaminated field site . Different numerical schemes for solving advective transport were compared to assess their capability to model low transversal dispersivities in transient flow fields . For the field site, it is shown that vertical plume spreading is largely inhibited, particularly if sorption is taken into account . For the reactive simulations, a biodegradation reaction module for the geochemical transport model PHT3D was developed . Results of the reactive transport simulations show that under the site-specific conditions the temporal variations in groundwater flow do, to a modest extent, affect average biodegradation rates and average total (dissolved) contaminant mass in the aquifer . The model simulations demonstrate that the seasonal variability in groundwater flow only results in significantly enhanced biodegradation rates when a differential sorption of electron donor (toluene) and electron acceptor (sulfate) is assumed. J Contam Hydrol, 2002 Nov, 59(1-2), 3 - 26 Persistence of LNAPL sources: relationship between risk reduction and LNAPL recovery; Huntley D et al.; Light nonaqueous phase liquids (LNAPLs), such as fuels, are the source of much soil and groundwater contamination . Though the mobility of LNAPLs is limited in many environments, dissolved-phase components, such as benzene, can produce groundwater plumes that are more mobile than the LNAPL source . In such a setting, it is commonly assumed that recovery of the LNAPL will result in a reduction in risk associated with the dissolved phase . This paper synthesizes several existing multiphase and chemical transport solutions into a single linked methodology that predicts concentrations of soluble constituents within and downgradient of LNAPL source zones from dissolution of those constituents into groundwater flowing through and below LNAPL sources . This approach has been applied to a variety of LNAPL spill conditions . For biodegradable compounds, these analyses show that the period of time where the dissolved-phase plume is expanding is very small compared to the duration of most LNAPL sources, and that the downgradient extent is generally less than about 100 m for BTEX compounds . Therefore, the risk to receptors, as measured by the maximum downgradient extent of dissolved-phase plume or the maximum concentration of these compounds at a downgradient receptor, is generally unrelated to the longevity of the LNAPL sources . The maximum downgradient extent of the dissolved-phase plume is determined almost entirely by the groundwater velocity and the biodegradation rate . These analyses further demonstrate that recovery of LNAPL by hydraulic methods is often ineffective at reducing risk . Except in coarse-grained soils or intermediate soils with significant LNAPL saturations, free-product recovery approaches do not result in significant reductions in the longevity of downgradient dissolved-phase contamination . Further, for biodegradable constituents, remediation does not result in a near-term decrease in the downgradient extent of contamination . Cleanup methods that act to change the composition of the LNAPL source are more effective at reducing the downgradient concentrations, particularly for fine-grained soils or when LNAPL saturations are low. Vasa, 2003 Feb, 32(1), 31 - 5 Ultrastructural analysis of an infected collagen-coated vascular graft; Freytag CC et al.; The incidence of infection following arterial reconstruction using synthetic graft materials varies from less than 1 to 5% . One of three mechanisms is thought to be responsible: 1 . intraoperative contamination, 2 . extension from adjacent infected or colonized tissue, or 3 . hematogenous or lymphogenous seeding . We present ultrastructural data of a patient with a polymicrobial graft infection due to a prostheto-enteric fistula 16 years after reconstruction of an aortobifemoral graft . The polymer surface showed signs of biodegradation and was completely covered with a layer of plasma proteins . Disrupted fibroblasts on the intersegmental graft surface were surrounded by bundles of collagen . Gram-negative rods and grampositive cocci were embedded in an extracellular EPS matrix . Bacterial culture confirmed growth of Eikenella corrodens, Fusobacterium nucleatum and Peptostreptococcus species . Fibrin and granulation tissue from the neoadventitia started to mark off the inflammatory process . Transmission electron microscopy is a valuable tool for the investigation of alloplastic arterial devices . After 16 years of implantation the graft shows different signs of biodegradation. Polim Med, 2002, 32(3-4), 40 - 7 Molecular and clinical consequences of in vivo silicones biodegradation; Lukasiak J et al.; The object of the publication is the presentation of data referring to in vivo silicones biodegradation and their potential clinical and molecular consequences . Summing up, one needs to state that the products of silicones biodegradation are not biologically indifferent . In particular, different types of silanols are inhibitors of proteolytic enzymes and regulators of many metabolic processes as well as affect the cell growth and division, which distinctly indicates the potentially strong pharmacological action . The main objective of the molecular consequences of the biodegradation of siloxanes was the verification what impact siloxanes of various molecular weights and of various chain lengths exert on the conformational stability of biological molecules. J Environ Biol, 2002 Oct, 23(4), 365 - 71 Biodegradation of wastewater of Najafgarh drain, Delhi using autochthonous microbial consortia : a laboratory study; Sharma G et al.; There are seventeen drains, which discharge their untreated urban and industrial wastewaters into the Delhi segment of river Yamuna . The Najafgarh drain is the first and the largest drain, and it alone contributes 1667.84 mld i.e . 60% of the total wastewater discharge into the river Yamuna and as such add 81.36 tons of BOD load per day . As per the available data approximately 95% of the wastewater of this drain is biodegradable . In the present study, an attempt has been made to reduce the BOD load and COD levels of wastewater of Najafgarh drain using autochthonous microbial consortium . During this study the raw wastewater samples were treated for 6 h time interval with different concentration of consortium . It was observed that by increasing the existing microbial population in the wastewater sample by 150-200% there is a significant decrease in BOD and COD levels . Finally, BOD/COD ratios before and after biotreatment have been analyzed to assess the efficacy of the natural consortium. Photochem Photobiol Sci, 2002 Sep, 1(9), 678 - 85 Effects of ultraviolet radiation and PAR on the content of usnic and divaricatic acids in two arctic-alpine lichens; Bjerke JW et al.; The fruticose lichen Flavocetraria nivalis and the crustose lichen Ophioparma ventosa, both common in light-exposed arctic-alpine environments, were exposed to ultraviolet radiation (UVR) in growth chambers for 30 days . Treatment with visible light (PAR) served as control . Both species accumulate the UV-absorbing phenolic compound usnic acid in the upper cortex . The latter species also synthesises several UV-absorbing medullary compounds, among them divaricatic acid . The effects of treatment with UVR on the synthesis of these two compounds were investigated by analysing the compounds quantitatively by RP-HPLC . UV-exposed thallus tips of F . nivalis contained higher concentrations of usnic acid than those not grown under UVR . Both treatments had a positive effect on the synthesis of usnic acid in O . ventosa . An additional experiment with O . ventosa was performed by first storing samples in a low-light habitat for 1 year to obtain near-zero levels of phenolics, and thereby exposing the samples to UVR and PAR for 90 days . A rapid resynthesis of usnic acid was observed for both treatments . The amounts of divaricatic acid were highly variable in all groups, and were not correlated with usnic acid concentrations or treatments . A comparison of O . ventosa from three different habitat types showed that the highest usnic acid amounts were found in the habitat with the highest levels of solar radiation . Results indicate that the induction of usnic acid production by UVR depends on the species studied, and on how well acclimatised the lichen samples are to solar radiation before they are exposed to supplementary UVR . In lichens with an already well-developed internal screening capacity, like the population of F . nivalis, enhanced UVR need not induce further accumulation of usnic acid, but removal of UVR may induce a biodegradation of usnic acid . Results also indicate that PAR is just as important as UVR for triggering the resynthesis of usnic acid in shade-adapted lichens . Divaricatic acid seems to be of low importance for the UV-screening properties of O . ventosa. Chemosphere, 2003 Jan, 50(3), 321 - 31 Comparison of biodegradation of surfactants in soils and sludge-soil mixtures by use of 14C-labelled compounds and automated respirometry; Gejlsbjerg B et al.; The biodegradability of dodecyl benzene sulphonate (LAS), nonylphenol-di-ethoxylate (NP2EO) and tridecyl-tetra-ethoxylate (LAE) in soil was examined by use of 14C experiments at two concentrations (10 and 400 mg/kg) . Increasing the concentration of test chemical from 10 to 400 mg/kg resulted in a decrease in the relative maximum mineralization rate and an increase in the estimated lag times of a factor of approximately 3.5 . In sludge-amended soil, the highest expected environmental concentration (just after sludge application) will be around 10 mg/kg for linear alkylbenzene sulphonate (LAS), while the concentration of NP2EO and linear alcohol ethoxylates (LAE) will be much lower . However, when using a respirometric method it is necessary to use a higher concentration of test substance in order to detect biodegradation . In our experiment, amendment with anaerobically digested sludge resulted in a decrease in the mineralization of LAS, NP2EO and LAE for all soils . Respirometric experiments were carried out at 400 mg/kg and could be used for estimation of biodegradation potential of LAS, NP2EO and LAE in soil and sludge-amended soil . For LAS, the results obtained from the respirometric experiments were similar to the results obtained in the 14C experiments, whereas NP2EO and LAE showed a faster degradation in the respirometric experiments. Chemosphere, 2003 Jan, 50(3), 303 - 9 Trichloroacetic acid in Norway spruce/soil-system . I . Biodegradation in soil; Matucha M et al.; Trichloroacetic acid (TCA) as a phytotoxic substance affects health status of coniferous trees . It is known as a secondary air pollutant (formed by photooxidation of tetrachloroethene and 1,1,1-trichloroethane) and as a product of chlorination of humic substances in soil . Its break-down in soil, however, influences considerably the TCA level, i.e . the extent of TCA uptake by spruce roots . In connection with our investigations of TCA effects on Norway spruce, microbial processes in soil were studied using 14C-labeling . It was shown that TCA degradation in soil is a fast process depending on TCA concentration, soil properties, humidity and temperature . As a result, the TCA level in soil is determined by a steady state between uptake from the atmosphere, formation in soil, leaching and degradation . The process of TCA degradation in soil thus participates significantly in the chlorine cycle in forest ecosystems. Chemosphere, 2003 Jan, 50(1), 29 - 38 Application of the headspace CO2 method (ISO 14 593) to the assessment of the ultimate biodegradability of surfactants: results of a calibration exercise; Painter HA et al.; In the recent review of the control of marketing surfactants used in detergents, the EU decided to increase the severity of the testing procedure by using the criterion of ultimate biodegradability (mineralization) rather than primary biodegradation (removal of the parent molecule) to ensure that possible harmful organic metabolites do not reach the environment . The relatively new ISO headspace CO2 test, considered to be an improvement on the OECD 301B (Sturm CO2) test was chosen . The method was subjected to a ring test by 11 laboratories using one of each of four classes of surfactants plus a poorly degradable reference surfactant; all laboratories satisfactorily applied the method . The necessary addition of silica gel to the medium containing the cationic surfactant, known as a class to be more inhibitory than other classes, was confirmed as a technique for avoiding inhibition of the inoculum . The biodegradability of the surfactants was in general agreement with results reported in the literature and the often reported variable values of % inorganic carbon (IC) produced of the theoretical was found . The anionic and cationic surfactants were readily biodegradable (%IC > 60), the non-ionic surfactant was well below the pass value, while the amphoteric was borderline . The IC production by the blank controls, one of the validity criteria, was about 0.3 mg C/100 ml test medium, equivalent to 3 mg C/l, as recommended in the ISO text . Mild conditions of pre-exposure of the inoculum to the test surfactant did not produce consistent worthwhile effects on either the percentage biodegradation or on its variability. Bioresour Technol, 2003 Jan, 86(2), 171 - 5 Anaerobic degradation of No . 2 diesel fuel in the wetland sediments of Barataria-Terrebonne estuary under various electron acceptor conditions; Boopathy R; The biodegradation of No . 2 diesel fuel under anaerobic conditions was investigated using sediments collected from wetlands of Barataria-Terrebonne estuary in Louisiana . The results indicated enhanced biodegradation of diesel fuel under sulfate-reducing, nitrate-reducing, methanogenic, and mixed electron acceptor conditions . However, the rate of diesel degradation was the highest under mixed electron acceptor conditions followed in order by sulfate-reducing, methanogenic, and nitrate-reducing conditions . Under mixed electron acceptor condition, 99% removal of diesel fuel was achieved within 510 days, while under sulfate-reducing condition 62% degradation of diesel fuel was observed for the same period . Diesel fuel was also degraded to a smaller extent in the culture condition where electron acceptors were not supplemented (natural attenuation condition) . This study showed evidence for enhanced diesel fuel metabolism in a mixed microbial population system similar to any contaminated field site, where a heterogeneous microbial population exists. Pest Manag Sci, 2003 Mar, 59(3), 259 - 68 Monitoring of atrazine treatment on soil bacterial, fungal and atrazine-degrading communities by quantitative competitive PCR; Martin-Laurent F et al.; We report the development of quantitative competitive (QC) PCR assays for quantifying the 16S, 18S ribosomal and atzC genes in nucleic acids directly extracted from soil . QC-PCR assays were standardised, calibrated and evaluated with an experimental study aiming to evaluate the impact of atrazine application on soil microflora . Comparison of QC-PCR 16S and 18S results with those of soil microbial biomass showed that, following atrazine application, the microbial biomass was not affected and that the amount of 16S rDNA gene representing 'bacteria' increased transitorily, while the amount of 18S rDNA gene representing fungi decreased in soil . In addition, comparison of atzC QC-PCR results with those of atrazine mineralisation revealed that, in response to atrazine treatment, the amount of atzC gene increased transitorily in soil pre-treated with atrazine, suggesting that accelerated atrazine biodegradation in soil could be due to a transient increase in the size of the atrazine mineralising community. Environ Sci Pollut Res Int, 2002, Spec No 1, 34 - 8 Applied waste-free recovery of methanol: a sustainable solution for chromatography laboratories; Stepnowski P et al.; In this paper, we present appliedmethanol recycling technology utilising chromatographic applications, which has been designed for an academic-size institution . The procedure is combined out of proper recovery technique and the biodegradation method intended for postprocessing residues . Additionally, analytical methods controlling the quality of the process are described in detail in order to enable full transfer of the proposed methodology to the analogous institution . The recovered solvent is of relatively high purity (> 99.92%), containing traces of water and volatile compounds . The spectral purity is sufficient to employ recycled methanol in HPLC applications where low wavelength detection is necessary . Biodegradation of distillation first-cuts and still bottoms is implemented using isolated strains of Methylobacterium organophilum . During the biodegradation process, a series of carotenoids are biosynthesized, which are of a high commercial value . The proposed application, therefore, offers not only a sustainable, waste-free solution in handling methanol waste, but can also serve as a potential source of value. Environ Sci Pollut Res Int, 2002, Spec No 1, 19 - 26 Biodegradation of dimethylphenols by bacteria with different ring-cleavage pathways of phenolic compounds; Viggor S et al.; The biodegradation of 3,4, 2,4, 2,3, 2,6 and 3,5-dimethylphenol in combination with phenol and p-cresol by axenic and mixed cultures of bacteria was investigated . The strains, which degrade phenol and p-cresol through different catabolic pathways, were isolated from river water continuously polluted with phenolic compounds of leachate of oil shale semicoke ash heaps . The proper research of degradation of 2,4 and 3,4-dimethylphenol in multinutrient environments was performed . The degradation of phenolic compounds from mixtures indicated a flux of substrates into different catabolic pathways . Catechol 2,3-dioxygenase activity was induced by dimethylphenols in Pseudomonas mendocina PC1, where meta cleavage pathway was functional during the degradation of p-cresol . In the case of strains PC18 and PC24 of P . fluorescens, the degradation of p-cresol occurred via the protocatechuate ortho pathway and the key enzyme of this pathway, p-cresol methylhydroxylase, was also induced by dimethylphenols . 2,4 and 3,4-dimethylphenols were converted into the dead-end products 4-hydroxy-3-methylbenzoic acid and 4-hydroxy-2-methylbenzoic acid . In the degradation of 3,4-dimethylphenol, the transient accumulation of 4-hydroxy-2-methylbenzaldehyde repressed the consumption of phenol from substrate mixtures . A mixed culture of strains with different catabolic types made it possible to overcome the incompatibilities at degradation of studied substrate mixtures. Environ Sci Pollut Res Int, 2002, Spec No 1, 8 - 14 Analysis of river pollution data from low-flow period by means of multivariate techniques: a case study from the oil-shale industry region, northeastern Estonia; Truu J et al.; The oil-shale industry has created serious pollution problems in northeastern Estonia . Untreated, phenol-rich leachate from semi-coke mounds formed as a by-product of oil-shale processing is discharged into the Baltic Sea via channels and rivers . An exploratory analysis of water chemical and microbiological data sets from the low-flow period was carried out using different multivariate analysis techniques . Principal component analysis allowed us to distinguish different locations in the river system . The riverine microbial community response to water chemical parameters was assessed by co-inertia analysis . Water pH, COD and total nitrogen were negatively related to the number of biodegradative bacteria, while oxygen concentration promoted the abundance of these bacteria . The results demonstrate the utility of multivariate statistical techniques as tools for estimating the magnitude and extent of pollution based on river water chemical and microbiological parameters . An evaluation of river chemical and microbiological data suggests that the ambient natural attenuation mechanisms only partly eliminate pollutants from river water, and that a sufficient reduction of more recalcitrant compounds could be achieved through the reduction of wastewater discharge from the oil-shale chemical industry into the rivers. Environ Sci Technol, 2003 Feb 15, 37(4), 691 - 700 Caffeine, an anthropogenic marker for wastewater comtamination of surface waters; Buerge II et al.; The suitability of caffeine as a chemical marker for surface water pollution by domestic wastewaters was assessed in this study . Caffeine concentrations in influents and effluents of Swiss wastewater treatment plants (WWTPs, 7-73 and 0.03-9.5 microg/L, respectively) indicated an efficient elimination of 81-99.9% . Corresponding loads in untreated wastewater showed small variations when normalized forthe population discharging to the WWTPs (15.8 +/- 3.8 mg person(-1) d(-1)), reflecting a rather constant consumption . WWTP effluent loads were considerably lower (0.06 +/- 0.03 mg person(-1) d(-1)), apart from installations with low sludge age (< or = 5 d, loads up to 4.4 mg person(-1) d(-1)) . Despite the efficient removal in most WWTPs, caffeine was ubiquitously found in Swiss lakes and rivers (6-250 ng/ L), except for remote mountain lakes (<2 ng/L; analytical procedure for wastewater and natural waters: SPE, GC-MS-SIM or GC-MS-MS-MRM, internal standard 13C3-labeled caffeine) . Caffeine concentrations in lakes correlated with the anthropogenic burden by domestic wastewaters, demonstrating the suitability of caffeine as a marker . A mass balance for Greifensee revealed that approximately 1-4% of the wastewaters had been discharged without treatment, presumably on rainy days when the capacity of WWTPs had been exceeded . For Zurichsee, it could be shown that the monthly inputs of caffeine correlated with precipitation data . The depth- and seasonal-dependent concentrations in this lake were adequately rationalized by a numerical model considering flushing, biodegradation, and indirect photodegradation via HO . radicals as elimination processes and caffeine inputs as fitting variables. Environ Health Perspect, 2002 Dec, 110 Suppl 6, 943 - 6 The role of cell bioaugmentation and gene bioaugmentation in the remediation of co-contaminated soils; Pepper IL et al.; Soils co-contaminated with metals and organics present special problems for remediation . Metal contamination can delay or inhibit microbial degradation of organic pollutants such that for effective in situ biodegradation, bioaugmentation is necessary . We monitored the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) or 3-chlorobenzoate (3-CB) in two different soils with and without cadmium (Cd) contamination . Additionally, we evaluated the ability of bioaugmentation to enhance organic degradation in these co-contaminated soils . Finally, we determined whether enhanced degradation was due to survival of the introduced organism (cell bioaugmentation) or plasmid transfer to indigenous microbial populations (gene bioaugmentation) . In Brazito soil, dual inoculation with a Cd-resistant bacterium plus a known 2,4-D-degrading bacterium, Ralstonia eutropha JMP134, enhanced 2,4-D degradation . Escherichia coli D11, which lacks chromosomal genes necessary for complete 2,4-D mineralization, was used for gene bioaugmentation in Madera soil . Significant gene transfer of the plasmid to the indigenous populations was observed, and the rate of 2,4-D degradation was enhanced relative to that of controls . Cell bioaugmentation was further demonstrated when (Comamonas testosteroni was used to enhance biodegradation of 3-CB in Madera soil . In this case no transfer of plasmid pBRC60 to indigenous soil recipients was observed . For the Madera soil, nonbioaugmented samples ultimately showed complete 2,4-D degradation . In contrast, nonbioaugmented Brazito soils showed incomplete 2,4-D degradation . These studies are unique in showing that both cell bioaugmentation and gene bioaugmentation can be effective in enhancing organic degradation in co-contaminated soils . Ultimately, the bioaugmentation strategy may depend on the degree of contamination and the time frame available for remediation. Biotechnol Appl Biochem, 2003 Apr, 37(Pt 2), 139 - 44 Phytoremediation of 2,4-dichlorophenol by Brassica napus hairy root cultures; Agostini E et al.; We have obtained hairy root cultures of Brassica napus with high biomass and genetic stability which produce peroxidases, enzymes involved in biodegradation processes . In this work, these hairy root cultures were used to study the removal of 2,4-dichlorophenol (2,4-DCP), a common contaminant in industrial effluents that is highly toxic for human and aquatic life . The optimum conditions to obtain high efficiency in the removal process were established . Roots were able to remove 2,4-DCP from aqueous solutions containing 100-1000 mg/l, in the presence of H(2)O(2) concentrations ranging from 5 to 10 mM . After a short period of incubation (15 min), high removal efficiencies were achieved (91-94%) and maximal removal, of approx . 97-98%, was obtained with 1 h of reaction . High removal efficiencies (93-95%) were observed in a broad pH range (pH 3-9), reaching 98-99% in the range pH 4-8 . Moreover, roots could be re-used, almost for six consecutive cycles, to remove 2,4-DCP . The oxidation catalysed by peroxidases would be the main mechanism involved in this process . The results suggest that these cultures could be useful tools for phytoremediation. Biomaterials, 2003 May, 24(12), 2003 - 11 Enzyme induced biodegradation of polycarbonate-polyurethanes: dose dependence effect of cholesterol esterase; Tang YW et al.; The current study has investigated the influence of esterase activity (80-400units/ml) on the biodegradation of polycarbonate-urethanes (PCNUs) by cholesterol esterase (CE), with a particular interest in studying the influence of different hard segment structures and their contribution to sensitizing the polymer towards enzyme catalyzed hydrolysis . Polycarbonate based polyurethanes were synthesized with varying hard segment content as well as hard segment chemistry based on three different diisocyanates, 1,6-hexane diisocyanate (HDI), 4,4'-methylene bisphenyl diisocyanate (MDI) and 4,4-methylene biscyclohexyl diisocyanate (HMDI) . The effect of different chemistry on surface contact angle was measured in order to define the relative chemical nature of the surfaces . The enzyme dose response was found to be lower when hard segment content in the polymer was high . There was a very strong dependence on enzyme concentration for polyurethanes with different hard segment chemistry, despite the fact that the nature of the hydrolysable polycarbonate segment remained the same . The PCNU which showed the most dramatic dependence on enzyme concentration was synthesized with HMDI . At low enzyme concentration (80units/ml) this material was the most stable of the polymers while at elevated CE concentration (400units/ml) the polymer underwent a catastrophic breakdown . The findings suggested that protein binding on the surfaces was saturated even though enzyme degradation did not achieve saturation on any of the surfaces . The role of protein binding in modulating the hydrolytic action of the enzymes at different activity levels highlights a need for further study in this area. Biomacromolecules, 2003 Mar-Apr, 4(2), 372 - 7 Lipase-catalyzed biodegradation of poly(epsilon-caprolactone) blended with various polylactide-based polymers; Li S et al.; Poly(epsilon-caprolactone) was blended with various polylactide-based polymers and processed to films by the solution casting method . Blends of 25/75, 50/50, 75/25, 90/10, and 95/5 (w/w) poly(epsilon-caprolactone)/poly(l-lactide), a 95/5 (w/w) blend of poly(epsilon-caprolactone) with a poly(d-lactide), a 50/50 (w/w) poly(l-lactide)-poly(d-lactide) mixture, and a poly(l-lactide-co-epsilon-caprolactone) copolymer were considered comparatively . The various phase-separated films were allowed to degrade in the presence of Pseudomonas lipase, biodegradation being monitored by proton nuclear magnetic resonance, size exclusion chromatography, differential scanning calorimetry, X-ray diffraction, and environmental scanning electron microscopy . The formation of separated phases during solvent evaporation and their morphologies are discussed . The introduction of poly(l-lactide) dramatically decreased the degradation rate of poly(epsilon-caprolactone)/poly(l-lactide) blends . The higher the percentage of poly(l-lactide), the slower the degradation, while the presence of cracks and increasing the lipase concentration acted in favor of the enzymatic degradation . Long-term enzymatic degradation of the various 95/5 blends was investigated over 480 h . The poly(epsilon-caprolactone) phase was enzymatically degraded by the lipase regardless of the blend type, the degradation rate depending on the nature of the co-components. Biomacromolecules, 2003 Mar-Apr, 4(2), 321 - 9 Degradation of vulcanized and nonvulcanized polyisoprene rubbers by lipid peroxidation catalyzed by oxidative enzymes and transition metals; Sato S et al.; Despite numerous reports concerning the biodegradation of rubber materials, there has been no report of rubber degradation by fully characterized enzymes . In the present paper, we presented a new method to decompose nonvulcanized and vulcanized polyisoprene rubbers by controlling the free radical chain reactions of lipids using oxidative enzymes, manganese peroxidase (MnP), laccase (Lac), and horseradish peroxidase (HRP) . Nonvulcanized synthetic polyisoprene (IR) was degraded by the free radicals from unsaturated fatty acids produced by MnP, HRP, and a combination of Lac/1-hydroxybenzotriazole . In contrast, lipoxygenase caused no apparent degradation . Degradation of IR was also observed in lipid peroxidation initiated by the Fenton reaction (FR) and Mn(III), an oxidation product produced by MnP . Vulcanized polyisoprene rubber sheets were degraded by the lipid peroxidation initiated by HRP, MnP, Mn(III), and FR . Pyrolysis GC-MS analysis demonstrated that the lipid peroxidation liberated isoprenoid fragments from the vulcanized rubbers. Int J Cardiovasc Intervent, 2003, 5(1), 13 - 6 Biodegradable stents as a platform to drug loading; Tsuji T et al.; Despite technical and mechanical improvement in coronary stents the incidence of restenosis caused by in-stent neointimal hyperplasia remains high . Oral administration of numerous pharmacological agents has failed to reduce restenosis after coronary stenting in humans, possibly owing to insufficient local drug concentration . Therefore, drug-eluting stents were developed as a vehicle for local drug administration . The authors developed a new drug-eluting polymer stent that is made of poly-l-lactic acid polymer mixed with tranilast, an anti-allergic drug that inhibits the migration and proliferation of vascular smooth muscle cells induced by platelet-derived growth factor and transforming growth factor->1 . Polymer stents might be superior to polymer-coated metallic stents as local drug delivery stents in terms of biodegradation and the amount of loaded drug . Drug-mixed polymer stents can be loaded with a larger amount of drug than can drug-coated metallic stents because the polymer stent struts can contain the drug . Clinical application is required to assess the safety and efficacy of drug-eluting polymer stents against stent restenosis. Appl Environ Microbiol, 2003 Mar, 69(3), 1532 - 41 Synergistic degradation of linuron by a bacterial consortium and isolation of a single linuron-degrading variovorax strain; Dejonghe W et al.; The bacterial community composition of a linuron-degrading enrichment culture and the role of the individual strains in linuron degradation have been determined by a combination of methods, such as denaturing gradient gel electrophoresis of the total 16S rRNA gene pool, isolation and identification of strains, and biodegradation assays . Three strains, Variovorax sp . strain WDL1, Delftia acidovorans WDL34, and Pseudomonas sp . strain WDL5, were isolated directly from the linuron-degrading culture . In addition, subculture of this enrichment culture on potential intermediates in the degradation pathway of linuron (i.e., N,O-dimethylhydroxylamine and 3-chloroaniline) resulted in the isolation of, respectively, Hyphomicrobium sulfonivorans WDL6 and Comamonas testosteroni WDL7 . Of these five strains, only Variovorax sp . strain WDL1 was able to use linuron as the sole source of C, N, and energy . WDL1 first converted linuron to 3,4-dichloroaniline (3,4-DCA), which transiently accumulated in the medium but was subsequently degraded . To the best of our knowledge, this is the first report of a strain that degrades linuron further than the aromatic intermediates . Interestingly, the rate of linuron degradation by strain WDL1 was lower than that for the consortium, but was clearly increased when WDL1 was coinoculated with each of the other four strains . D . acidovorans WDL34 and C . testosteroni WDL7 were found to be responsible for degradation of the intermediate 3,4-DCA, and H . sulfonivorans WDL6 was the only strain able to degrade N,O-dimethylhydroxylamine . The role of Pseudomonas sp . strain WDL5 needs to be further elucidated . The degradation of linuron can thus be performed by a single isolate, Variovorax sp . strain WDL1, but is stimulated by a synergistic interaction with the other strains isolated from the same linuron-degrading culture. Biosci Biotechnol Biochem, 2003 Jan, 67(1), 218 - 20 Biodegradation of bisphenol A by cultured cells of Caragana chamlagu; Chai W et al.; The biological degradation of 2,2-bis(4-hydroxyphenol)propane (1; bisphenol A, BPA), a representative endocrine disruptor, was studied with plant-cultured cells of Caragana chamlagu . An initial BPA concentration of 425 microM in an aqueous solution was degraded by C . chamlagu at 25 degrees C for 2 days in the dark, and two intermediates were then completely dissipated after 10 days. J Bacteriol, 2003 Mar, 185(6), 2026 - 30 Identification and functional characterization of Sphingomonas macrogolitabida strain TFA genes involved in the first two steps of the tetralin catabolic pathway; Moreno-Ruiz E et al.; Five genes involved in the two initial steps of the tetralin biodegradation pathway of Sphingomonas macrogolitabida strain TFA have been characterized . ThnA1A2 and ThnA3A4, components of the ring-hydroxylating dioxygenase, were encoded in divergently transcribed operons . ThnA1, ThnA2, and ThnA3 were essential for tetralin ring-hydroxylating dioxygenase activity . ThnB was identified as a dehydrogenase required for tetralin biodegradation. Chemosphere, 2003 May, 51(6), 529 - 37 Biodegradation of chemicals in a standardized test and in environmental conditions; Ahtiainen J et al.; The estimation of biodegradation rates is an important source of uncertainty in chemical risk assessment . The existing OECD tests for ready biodegradability have been developed to devise screening methods to determine whether a chemical is potentially easily biodegradable, rather than to predict the actual rate, of biodegradation in the environment . However, risk assessment needs degradation rates . In practice these rates are often estimated (default values) from ready biodegradability tests . These tests have many compromising arbitrary features compared to the situation in the real environment . One important difference is the concentration of the chemical . In wastewater treatment or in the environment many chemicals are present at ng l(-1) to microg l(-1) levels whereas in the tests the concentrations exceed 10-400 mg carbon per litre . These different concentrations of the chemical will lead to different growth kinetics and hence different biodegradation rates . At high concentrations the chemical, if it is degradable, can serve as a primary substrate and competent microorganisms will grow exponentially, resulting in a sigmoid biodegradation curve . At low environmental concentrations the chemical does not serve as a primary substrate, and therefore does not support significant growth of the degraders, and the substrate has a linear biodegradation rate . In this study the biodegradation rates of two reference chemicals, aniline and 4-chloroaniline, were compared in a standard method and in more realistic conditions at low concentrations, using 14C-labelled substances and different sources of inocula . Biomass evolution during the tests was monitored by adenosine triphosphate measurement and also on the basis of the residual 14C-activity in the particulate matter . The results partly support the thesis that low concentrations lead to different biodegradation kinetics compared to the concentrations used in the standard tests . Furthermore the biodegradation rates of the chemicals studied, particularly of 4-chloroaniline, in Finnish natural waters appeared to be lower than those reported in some other countries. J Biomater Appl, 2003 Jan, 17(3), 183 - 96 Oral insulin--a perspective; Raj NK et al.; Diabetes mellitus is generally controlled quite well with the administration of oral medications or by the use of insulin injections . The current practice is the use of one or more doses, intermediate or long acting insulin per day . Oral insulin is a promising yet experimental method providing tight glycemic control for patients with diabetes . A biologically adhesive delivery systems offer important advantage over conventional drug delivery systems . The engineered polymer microspheres made of erodable polymer display strong adhesive interactions with gastrointestinal mucus and cellular lining can traverse both the mucosal epithelium and the follicle associated epithelium covering the lymphoid tissue of Peyer's patches . Alginate, a natural polymer recovered from seaweed is being developed as a nanoparticle for the delivery of insulin without being destroyed in the stomach . Alginate is in fact finding application in biotechnology industry as thickening agent, a gelling agent and a colloid stabilizer . Alginate has in addition, several other properties that have enabled it to be used as a matrix for entrapment and for the delivery of a variety of proteins such as insulin and cells . These properties include: a relatively inert aqueous environment within the matrix; a mild room temperature encapsulation process free of organic solvents; a high gel porosity which allows for high diffusion rates of macromolecules; the ability to control this porosity with simple coating procedures and dissolution and biodegradation of the system under normal physiological conditions. J Chromatogr A, 2003 Feb 14, 987(1-2), 395 - 402 Process monitoring of anaerobic azo dye degradation by high-performance liquid chromatography-diode array detection continuously coupled to membrane filtration sampling modules; Plum A et al.; Process integrated microfiltration and ultrafiltration based membrane sampling modules were compared by means of HPLC with diode array detection based monitoring of an anaerobic azodye biodegradation process . The sampling matrix consisted of anaerobic sludge from a municipal wastewater treatment plant . The hydrolysed azo dye Reactive Black 5 (RB5-H) and three products (ionic and nonionic) released from reductive cleavage under anaerobic conditions were continuously monitored by simultaneously separation by ion-pair chromatography . Microfiltration membrane-based sampling showed no retention for any compound observed . Sampling by ultrafiltration significantly retained the observed ionic compounds between 58 and 83% whereas a nonionic compound was not retained . On-line monitoring of an oxygen-sensitive compound was possible whereas off-line detection failed . Robust long time monitoring could be performed for up to 1 week without cleaning the membrane. Environ Int, 2003 Mar, 28(8), 687 - 90 An assessment of the toxicity of pyridinium chlorides and their biodegradation intermediates; Grabinska-Sota E et al.; Toxicity investigations were conducted for four pyridinium chlorides belonging to cationic surface-active substances (CSAS), which differed from each other in the numbers of methyl groups (CH(3)) in pyridinium ring.The crustacean Daphnia magna, the fish Lebistes reticulatus and the alga Scenedesmus quadricauda were chosen as biotests . Toxicity of examined preparations appeared to be very high but did not depend on their chemical structure . S . quadricauda was the most sensitive organism . Toxicity of intermediate products obtained in biological oxidation process was also examined . Biodegradation was conducted according to the "river water test" . It was found that only partial degradation took place while pyridinium chlorides constituted main energy and carbon source . Presence of biodegradation intermediate products was shown on the basis of 1H NMR analysis . Intermediates were not toxic to any biotests. Hua Xi Kou Qiang Yi Xue Za Zhi, 2002 Jun, 20(3), 172 - 4, 183 {A fundamental study on bioreactions of Sr-HA}; Liao D et al.; OBJECTIVE: Sr-HA, a new type of hydroxyapatite biomaterial, was implanted into animals to study the bioreaction and character, which would be helpful for the further clinical applications in the future . METHODS: Totally 24 rabbits were divided into 3 groups . The bone defect of 6 mm x 12 mm x 4 mm was made at both mandibular angles of rabbits and Sr-HA of different proportion (10%, 5%, 0) was applied to reform the defects . One group of animals were killed randomly at 1, 3 and 6 months after operation to evaluate the material biological compatibility using anatomic, X-ray examination, histological and ECT methods . RESULTS: The histological photographs showed that Sr-HA caused little infection around implanted area and, almost was not repulsed by hosts . With the degradation of biomaterial, there was more apparent new bone growth in the area around Sr-HA than that around HA and some ossification can be found in soft tissue nearby . Also a tight osteointegrity was gradually got after the operation, according to the results of X-ray and, the border between Sr-HA and bone was hardly discovered at the 6th month after the operation . A more obvious nuclide assembling was observed at the side of Sr-HA by ECT images . With the biodegradation of Sr-HA, more new bone was intruded into the spare space of the biomaterial . CONCLUSION: Sr-HA has better biocompatibility and higher biodegradation than that of pure HA . It holds an excellent osteoinductivity and fair osteoconductivity to some degree too . So a more satisfying effect of bone defect rehabilitation was gained with the increasing new bone depositing in the free space of the material, when it degraded gradually. Biosci Biotechnol Biochem, 2002 Dec, 66(12), 2755 - 8 Cloning, sequencing, and overexpression in Escherichia coli of a phenylserine dehydratase gene from Ralstonia pickettii PS22; Okuda H et al.; The structural gene coding for phenylserine dehydratase from Ralstonia pickettii PS22 was cloned into Escherichia coli cells, and the nucleotide sequence was identified . The predicted amino acid sequence had high sequence similarity to biodegradative and biosynthetic threonine dehydratases from E . coli and serine dehydratase from human liver . Transformed E . coli cells overproduced phenylserine dehydratase, and the recombinant enzyme was purified to homogeneity with a high yield and characterized. Aquat Toxicol, 2003 Feb 26, 62(4), 305 - 19 In vivo metabolism and organ distribution of a branched 14C-nonylphenol isomer in pond snails, Lymnaea stagnalis L; Lalah JO et al.; The branched isomers of p-nonylphenol (NP) are perceived to be more resistant to biodegradation in aquatic environments as well as to have more estrogen-like toxicity than the straight chain isomers . By use of GC-MS, some of them have been identified and found to exist in higher concentrations in the isomeric compound mixture than the straight chain isomers . The investigations of the distribution and metabolism of these branched isomers in aquatic organisms are therefore considered to be important in understanding the mechanisms of toxicity of NP . A single tertiary isomer of NP, 4(3'-,6'-dimethyl-3'-heptyl)-phenol, was synthesized in the laboratory and used in in vivo studies of its organ distribution and metabolism in Lymnaea stagnalis L., following a constant exposure of the organisms to 14C-NP isomer in water over a period of 8 days at an average exposure concentration of 105 ppb (range: 93-116 ppb) . The results obtained clearly showed the distribution and bioconcentration of the isomer residues in various internal organs of Lymnaea after uptake in water and food . Analysis of the extracts of the organ tissues and faeces by HPLC and GC-MS after digestion with Pankreatin/beta-glucuronidase and nitric acid, respectively, showed that the isomer was metabolized by conjugation to glucuronic acid and hydroxylation to a catechol . The findings from these studies and their implications in the biotransformation and estrogenicity of NP in Lymnaea stagnalis L . are further discussed in detail in this paper. J Control Release, 2003 Feb 14, 88(1), 55 - 64 Repairing of rabbit skull defect by dehydrothermally crosslinked collagen sponges incorporating transforming growth factor beta1; Ueda H et al.; Collagen sponges of various biodegradabilities were prepared by dehydrothermal crosslinking at 140 degrees C for different time periods . When the collagen sponges were radioiodinated and implanted subcutaneously into the back of mice, the radioactivity remaining at the implanted site decreased with time; the longer the time of dehydrothermal crosslinking, the slower the radioactivity decrement . The radioactivity following the subcutaneous implantation of collagen sponges incorporating (125)I-labeled transforming growth factor (TGF)-beta1 also decreased with time . The time profile of both the radioactivity remainings was in good accordance to each other, irrespective of the crosslinking time . This indicates that the TGF-beta1 incorporated in the sponges was released as a result of sponge biodegradation . Potential of collagen sponges incorporating 0.1 micro g of TGF-beta1 in repairing the defect of rabbit skulls was evaluated in a stress-unloaded state . Bone repairing was induced by application of the collagen sponges incorporating 0.1 micro g of TGF-beta1 whereas that of free TGF-beta1 at the same dose and TGF-beta1-free, empty collagen sponges were ineffective . The bone defect was histologically closed by the bone tissue newly formed 6 weeks after application . Bone mineral density (BMD) analysis revealed that the collagen sponge incorporating TGF-beta1 enhanced the BMD value at the bone defect to a significantly great extent compared with other agents . A maximum enhancement of BMD was observed for the collagen sponge incorporating TGF-beta1 which was prepared by dehydrothermal crosslinking for 6 h . It was concluded that the TGF-beta1 incorporated in the collagen sponge was released in a biologically active form as a result of sponge biodegradation, resulting in enhanced bone repairing at the skull defect . It is possible that for too slowly degraded sponges, the remaining physically impairs the bone repairing at the skull defect . Induction of bone repairing would not be achieved through a rapid release of TGF-beta1 from too fast-degraded sponge. Lett Appl Microbiol, 2003, 36(3), 173 - 6 Biodegradation of the synthetic pyrethroid cypermethrin in used sheep dip; Grant RJ et al.; AIMS: To investigate the breakdown of cypermethrin synthetic pyrethroid (SP) insecticide-based used sheep dip (USD), with its indigenous microbial community and two previously isolated SP-degrading microorganisms . METHODS AND RESULTS: Cultures of USD (50 ml) containing 250 ml l(-1) cypermethrin were inoculated with the SP-degrading organisms and incubated at 25 degrees C with agitation at 80 rev min(-1) for 14 days . The viable cell counts and concentration of cypermethrin were monitored . A non-stimulated control was also carried out . The previously isolated bacteria were the most effective at degrading cypermethrin, leaving approximately two-thirds the concentration of SP as was found in the control . The non-stimulated cultures showed negligible breakdown of SP over the experimental period . CONCLUSIONS: The previously isolated SP-degrading bacteria could have a use in the treatment of SP USD . SIGNIFICANCE AND IMPACT OF STUDY: In situ treatment of SP-based USDs to detoxify the active ingredient before disposal could be very useful in helping to deal with agricultural pesticide waste . Such an approach, or by ex situ treatment would be more preferable to current methods, such as those of incineration and disposal to land. Adv Space Res, 2003, 31(1), 249 - 53 Biodegradation pathway of an anionic surfactant (Igepon TC-42) during recycling waste water through plant hydroponics for advanced life support during long-duration space missions; Levine LH et al.; The degradation of an anionic surfactant (Igepon TC-42) was investigated as part of an integrated study of direct recycling of human hygiene water through hydroponic plant growth systems . Several chemical approaches were developed to characterize the degradation of Igepon and to measure the accumulation of intermediates such as fatty acids and methyl taurine . Igepon was rapidly degraded as indicated by the reduction of methylene blue active substances (MBAS) and component fatty acids . The Igepon degradation rate continued to increase over a period of several weeks following repeated daily exposure to 18 micrograms/l Igepon . The accumulation of free fatty acids and methyl taurine was also observed during decomposition of Igepon . The concentration of methyl taurine was below detection limit (0.2 nmol/ml) during the slow phase of Igepon degradation, and increased to 1-2 nmol/ml during the phase of rapid degradation . These findings support a degradation pathway involving initial hydrolysis of amide to release fatty acids and methyl taurine, and subsequent degradation of these intermediates . Published by Elsevier Science Ltd on behalf of COSPAR. J Biomed Mater Res A, 2003 Mar 1, 64(3), 551 - 9 Controlled release of fibroblast growth factors and heparin from photocrosslinked chitosan hydrogels and subsequent effect on in vivo vascularization; Ishihara M et al.; Application of ultraviolet (UV) irradiation to a photocrosslinkable chitosan (Az-CH-LA) aqueous solution resulted within 10 s in an insoluble, flexible hydrogel . A low molecular weight acidic molecule like trypan blue and various high molecular weight molecules such as bovine serum albumin (BSA), heparin and protamine were all retained within the hydrogel, while a low molecular weight basic molecule like toluidine blue was rapidly released from the hydrogel . In the present work, we examined the retaining capability of the chitosan hydrogel for growth factors and controlled release of growth factors from the chitosan hydrogel in vitro and in vivo . Fibroblast growth factor-1 (FGF-1), fibroblast growth factor-2 (FGF-2), vascular endothelial growth factor(165) (VEGF(165)), heparin-binding epidermal growth factor (HB-EGF) in phosphate buffered saline (PBS) were mixed with Az-CH-LA aqueous solution to form growth factor-incorporated chitosan hydrogels . About 10-25% of the growth factor was released from a growth factor-incorporated chitosan hydrogel into PBS within the first day, after which no further substantial release took place . The growth factors interacted with Az-CH-LA molecules poly-ion complexation, and probably were unable to be released after the first day under the in vitro nondegradation conditions of the hydrogel . Although the FGF-1, FGF-2, and VEGF(165)-incorporated chitosan hydrogels on a culture plate significantly stimulated HUVEC growth, the stimulating activity of the growth factor-incorporated chitosan hydrogel was completely cancelled out by washing the hydrogel with PBS solution for 3 days or more . The stimulating activity on the HUVEC growth were however highly recovered by treating the washed growth factor-incorporated chitosan hydrogel during 7 days with chitinase and chitosanase to partly degrade the hydrogel, strongly suggesting that the growth factors within the hydrogel retained their biologically active forms . The chitosan hydrogel (100 microl) when implanted into the back of a mouse was biodegraded in about 10-14 days . When FGF-1- and FGF-2-incorporated chitosan hydrogels were subcutaneously implanted into the back of a mouse, significant neovascularization was induced near the implanted site of the FGF-1- and FGF-2-incorporated chitosan hydrogels . Furthermore, addition of heparin with either FGF-1 or FGF-2 into the hydrogel resulted in a significantly enhanced and prolonged vascularization effect . These results indicate that the controlled release of biologically active FGF-1 and FGF-2 with heparin is caused by biodegradation of the chitosan hydrogel, and subsequent induction of vascularization . Water Sci Technol, 2003, 47(1), 291 - 6 The performance of a two-stage SBR system in treating dye containing wastewater; Won XH et al.; A two-stage SBR system treating the wastewater containing copper-phthalocyanin dye-Reactive Turquoise Blue KN-G (C . I . Reactive Blue 21, denoted by RTB) was investigated during a 200-cycle operation . The performance of the system, including pollutant removal rates, operating stability and sludge characteristics, may be a concern in the long-term run . The results shows that the system removed RTB efficiently despite the step-up RTB concentration from 13.1 to 107 mg/L in the influent . The average total removal rates of RTB were 81% to 92.5% due to the contribution of both anaerobic and aerobic stages, while stable effluent was produced with the help of the aerobic stage . The sludge in each reactor was in the steady state and of good activity on RTB removal . Moreover, the anaerobic sludge with the SVI value of 109.1 and the aerobic sludge with the SVI value of 103.2 had good settling properties, which was verified by hardly any presence of suspended solids in the effluent and an observation under an electron-scanning microscope . The adsorption and biodegradation were considered as the mechanism for the stability of the SBR system during the long-term run. Water Sci Technol, 2003, 47(1), 113 - 20 Granular activated carbon (GAC) adsorption in tertiary wastewater treatment: experiments and models; Chaudhary DS et al.; Wastewater treatment has always been a major concern in the developed countries . Over the last few decades, activated carbon adsorption has gained importance as an alternative tertiary wastewater treatment and purification process . In this study, granular activated carbon (GAC) adsorption was evaluated in terms of total organic carbon (TOC) removal from low strength synthetic wastewater . This paper provides details on adsorption experiments conducted on synthetic wastewater to develop suitable adsorption isotherms . Although the inorganics used in the synthetic wastewater solution had an overall unfavourable effect on adsorption of organics, the GAC adsorption system was found to be effective in removing TOC from the wastewater . This study showed that equation of state (EOS) theory was able to fit the adsorption isotherm results more precisely than the most commonly used Freundlich isotherm . Biodegradation of the organics with time was the most crucial and important aspect of the system and it was taken into account in determining the isotherm parameters . Initial organic concentration of the wastewater was the determining factor of the model parameters, and hence the isotherm parameters were determined covering a wide range of initial organic concentrations of the wastewater . As such, the isotherm parameters derived using the EOS theory could predict the batch adsorption and fixed bed adsorption results of the multi-component system successfully . The isotherm parameters showed a significant effect on the determination of the mass transfer coefficients in batch and fixed bed systems. Bioresour Technol, 2003 May, 88(1), 69 - 74 Kinetics of anaerobic biodegradation of resorcinol catechol and hydroquinone in upflow fixed film-fixed bed reactors; Latkar M et al.; Biodegradation of resorcinol, catechol and hydroquinone under anaerobic conditions was studied in identical upflow fixed film-fixed bed reactors . Kinetic constants; V(max) (maximum substrate utilization rate) and K(s) (Monod's half saturation constant) were determined for the three compounds using Lineweaver-Burk plot . V(max) for resorcinol was highest, followed by catechol and then by hydroquinone . When both resorcinol and catechol were fed to the resorcinol-acclimated reactor, resorcinol degradation was inhibited by catechol . The inhibition was of the uncompetitive type and V(max) for resorcinol was reduced by catechol. Appl Environ Microbiol, 2003 Feb, 69(2), 909 - 16 Arthrobacter strain VAI-A utilizes acyl-homoserine lactone inactivation products and stimulates quorum signal biodegradation by Variovorax paradoxus; Flagan S et al.; Many Proteobacteria produce acyl-homoserine lactones (acyl-HSLs) and employ them as dedicated cell-to-cell signals in a process known as quorum sensing . Previously, Variovorax paradoxus VAI-C was shown to utilize diverse acyl-HSLs as sole sources of energy and nitrogen . We describe here the properties of a second isolate, Arthrobacter strain VAI-A, obtained from the same enrichment culture that yielded V . paradoxus VAI-C . Although strain VAI-A grew rapidly and exponentially on a number of substrates, it grew only slowly and aberrantly (i.e., linearly) in media amended with oxohexanoyl-HSL as the sole energy source . Increasing the culture pH markedly improved the growth rate in media containing this substrate but did not abolish the aberrant kinetics . The observed growth was remarkably similar to the known kinetics of the pH-influenced half-life of acyl-HSLs, which decay chemically to yield the corresponding acyl-homoserines . Strain VAI-A grew rapidly and exponentially when provided with an acyl-homoserine as the sole energy or nitrogen source . The isolate was also able to utilize HSL as a sole source of nitrogen but not as energy for growth . V . paradoxus, known to release HSL as a product of quorum signal degradation, was examined for the ability to support the growth of Arthrobacter strain VAI-A in defined cocultures . It did . Moreover, the acyl-HSL-dependent growth rate and yield of the coculture were dramatically superior to those of the monocultures . This suggested that the original coenrichment of these two organisms from the same soil sample was not coincidental and that consortia may play a role in quorum signal turnover and mineralization . The fact that Arthrobacter strain VAI-A utilizes the two known nitrogenous degradation products of acyl-HSLs, acyl-homoserine and HSL, begins to explain why none of the three compounds are known to accumulate in the environment. J Biotechnol, 2003 Mar 6, 101(2), 119 - 30 Function and mechanism of a low-molecular-weight peptide produced by Gloeophyllum trabeum in biodegradation of cellulose; Wang W et al.; A special low-molecular-weight peptide named Gt factor, was isolated and purified via HPLC from the culture extract of the brown-rot fungus Gloeophyllum trabeum . It had high-affinity Fe(3+)-chelating ability and could reduce Fe(3+) to Fe(2+) . In the presence of O(2), it could produce hydroxyl radicals HO* . The effects of Gt factor on cellulose degradation suggested that Gt factor could disrupt inter- and intra- hydrogen bonds in cellulose chains by a HO*-involved mechanism . This resulted in depolymerization of cellulose chains, which produced more reducing and non-reducing ends, thus making cellulose accessible for further degradation . This pathway was quite different from the hydrolytic processes driven by cellulases, and Gt factor might play an important role in the early stage of cellulose depolymerization by brown-rot fungi . J Agric Food Chem, 2003 Feb 12, 51(4), 947 - 56 Biodegradation of oak (Quercus alba) wood during growth of the shiitake mushroom (Lentinula edodes): a molecular approach; Vane CH et al.; The chemical transformations that occur during growth of the shiitake mushroom (Lentinula edodes) on oak (Quercus alba) were investigated to improve mushroom cultivation and utilization of the spent substrate . Oak logs were decayed by L . edodes over 8 years, during which time they were sampled at six intervals (30, 40, 66, 76, 77, and 101 months) . Fresh and decayed oak samples were analyzed using solid-state (13)C NMR and pyrolysis-gas chromatography-mass spectrometry as well as off-line thermochemolysis with tetramethylammonium hydroxide . Degraded oak exhibited lower carbon contents and increased oxygen content compared to the control . Solid-state (13)C NMR analysis revealed that polysaccharides were the major component of both fresh and decayed oak but that L . edodes mediated the preferential loss of cellulose and xylans as compared to lignin, which remained in an altered form . Several trends point toward the degradation of lignin, including a decrease in the proportion of syringyl units as compared to guaiacyl units and a reduction in side-chain length . An increase in guaiacyl and syringyl acid-to-aldehyde ratios occurred with growth, which suggested that the fungus had caused oxidation of Calpha-Cbeta bonds . The overall effect of L . edodes on oak is similar to that of many white-rot fungi, which simultaneously degrade all cell wall components. Environ Sci Technol, 2003 Jan 15, 37(2), 321 - 7 Fate of nonylphenol ethoxylates and their metabolites in two Dutch estuaries: evidence of biodegradation in the field; Jonkers N et al.; The environmental behavior of nonylphenol ethoxylates (A9PEO) and their metabolites was investigated in field studies in the two Dutch estuaries Western Scheldt and the Rhine estuary . Using liquid chromatography-electrospray mass spectrometry (LC-ES-MS) analysis after solid-phase extraction, A9PEO, nonylphenol (NP), and the carboxylated metabolites (A9PEC) were determined in surface water and sediments . Maximum dissolved concentrations of 2.3, 0.9, and 8.1 microg L(-1), respectively, were found . In sediments, maximum concentrations of 242 and 1080 ng g(-1) for A9PEO and NP were observed . In almost half of the sediment samples, concentrations of A9PEC in sediments were below the detection limit . Occasionally relatively high values were observed, with a maximum of 239 ng g(-1) . Metabolites of the carboxy alkylphenoxy ethoxy acetic acids (CAPEC) type could not be detected in any of the sediment or water samples . In the Scheldt estuary, dissolved concentration profiles showed nonconservative behaviorfor all detected compound groups . While A9PEO and NP concentrations strongly decreased along the salinity gradient, this decrease was weaker for the A9PEC metabolites . The increasing concentration ratio of A9PEC/A9PEO clearly illustratesthe important role that aerobic biodegradation plays in the estuarine fate of these compounds . It is concluded that the oxidative hydrolytic degradation pathway is the main degradation route in this nonstratified estuary . At high salinities, where concentrations drop to background levels of around 50 ng L(-1), this ratio decreases to about unity . Simple model calculations show that this can be explained if continuous diffuse discharges (e.g . from the intensive shipping in the estuary) are assumed . For the stratified Rhine estuary the water concentration profiles are less pronounced, possibly due to more complicated and turbulent water flows and point sources from the Rotterdam harbors. Biomaterials, 2003 Apr, 24(9), 1621 - 9 The properties of chitosan-gelatin membranes and scaffolds modified with hyaluronic acid by different methods; Mao JS et al.; The objective of the present study was to investigate the properties of chitosan-gelatin membranes or scaffolds, which were modified by incorporation of hyaluronic acid in the surface or bulk phase through co-crosslinking with N,N-(3-dimethylamino-propyl)-N'-ethyl carbodiimide (EDC) and N-hydroxysuccinimide (NHS) in 2-morpholinoethane sulfonic acid (MES) buffer . The comparative study on properties of surface modification (HA(S)) and polyblend membranes (HA(C)) revealed that gelatin was enriched on the surface of HA(C), while hyaluronic acid was enriched on the surface of the HA(S) . The HA(S) membranes made by surface modification method had a characteristic surface morphology . The corresponding scaffolds were prepared through freeze-drying . The incorporation of hyaluronic acid improved flexibility and fibroblasts adhesion, while slowing down the rate of biodegradation of chitosan-gelatin scaffold . Human fibroblasts adhered and proliferated well on the membranes or scaffolds in vitro. Environ Toxicol Chem, 2003 Feb, 22(2), 272 - 5 Quantitative structure-biodegradation relationship study for biodegradation rates of substituted benzenes by river bacteria; Lu GH et al.; The biodegradation rate constant (K) of 21 substituted phenols, anilines, and benzoic acids was determined by using bacteria from the Songhua River (Jilin Province, China) as an inoculum . All of the compounds studied are readily biodegradable chemicals, as shown by their high K values . The quantitative structure-biodegradation relationship results showed that the biodegradation rate of the studied compounds is related mainly to the heat of formation (Hf) and the negative logarithm of the ionization constant (pKa), whereas no simple relationship exists with the n-octanol-water partition coefficients . The equation K = - 1.127 x 10(-3)Hf - 0.0388pKa + 0.859 was found to fit well (r2(adj) = 0.805), and the correlation coefficient between the predicted and the experimental K values was up to 0.908. Wei Sheng Wu Xue Bao, 1999 Apr, 39(2), 127 - 31 {Comparison of lignocellulolytic enzyme profiles secreted by Panus conchatus and Phanerochaete chrysosporium during solid state cultures}; Wang C et al.; Most of white-rot fungi, such as Phanerochaete chrysosporium, can cause severe concomitant cellulose degradation during biodegradation of lignocellulose . Panus conchatus, a white-rot fungus, can cause efficient delignification of straw with only limited concomitant cellulose degradation . The results in comparison of lignocellulolytic enzyme profiles secreted by P . conchatus and P . chrysosporium during solid state cultures have shown that laccase and Mn-dependent peroxidase are main lignin-degrading enzymes of these two fungi respectively; high activities of xylanase are secreted by both fungi; and much lower activities of cellulases i.e . endo-glucanase, avicelase and cellobiase, especially endo-glucanase, are produced by P . conchatus during the whole cultures . The results further confirm that Panus conchatus has ability of strong selective delignification of lignocellulose. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi, 1998 Dec, 15(4), 323 - 4 {Preparation of chitosan-gelatin mixed film and study on it's biodegradability}; Lu F et al.; A chitosan-gelatin film is prepared and the biodegradability and biocompatibility of the film are investigated by animal experiments . Results suggest that chitosan-gelatin film may be biodegraded faster and it has good biocompatibility . Lysozyme may promote biodegradation of the mixed film. Waste Manag Res, 2002 Dec, 20(6), 514 - 28 Modelling for environmental assessment of municipal solid waste landfills (part II: biodegradation); Garcia de Cortazar AL et al.; The biodegradation module of a simulation program for municipal solid waste landfills (MODUELO) was developed . The biodegradation module carries out the balance of organic material starting with the results of the hydrologic simulation and the waste composition . It simulates the biologic reactions of hydrolysis of solids and the gasification of the dissolved biodegradable material . The results of this module are: organic matter (COD, BOD and elemental components such as carbon, hydrogen, nitrogen, oxygen, sulfur and ash), ammonium nitrogen generated with the gas and transported by the leachates and the potential rates of methane and carbon dioxide generation . The model was calibrated by using the general tendency curves of the pollutants recorded in municipal solid waste landfills, fitting the first part of them to available landfill data . Although the results show some agreement, further work is being done to make MODUELO a useful tool for real landfill simulation. J Environ Qual, 2003 Jan-Feb, 32(1), 40 - 6 Transport and biodegradation of perchlorate in soils; Tipton DK et al.; Perchlorate (ClO4-) contamination of ground water and surface water is a widespread problem, particularly in the western United States . This study examined the effect of biodegradation on perchlorate fate and transport in soils . Solute transport experiments were conducted on two surface soils . Pulses of solution containing perchlorate and Br- were applied to saturated soil columns at steady state water flow . Perchlorate behaved like a nonreactive tracer in Columbia loam (coarse-loamy, mixed, superactive, nonacid, thermic Oxyaquic Xerofluvent) but was degraded in Yolo loam (fine-silty, mixed, superactive, nonacid, thermic Mollic Xerofluvent) . Batch experiments demonstrated that perchlorate removal from solution in Yolo loam was caused by biodegradation . Other batch experiments with Yolo loam surface and subsurface soils, Columbia loam surface soil, and dredge tailings demonstrated that perchlorate biodegradation required anaerobic conditions, an adequate carbon source, and an active perchlorate-degrading microbial population . The sequential reduction of perchlorate and NO3- by an indigenous soil microbial community in Yolo loam batch systems was also studied . Nitrate reduction occurred much sooner than perchlorate reduction in soils that had not been previously exposed to perchlorate, but NO3- and perchlorate were simultaneously reduced in soils previously exposed to perchlorate . The results of this study have implications for in situ remediation schemes and for agricultural soils that have been contaminated by perchlorate-tainted irrigation water. Wei Sheng Wu Xue Bao, 1998 Feb, 38(1), 63 - 9 {The biodegradation of trichloroethylene by a methanotrophic bacterium}; Shen R et al.; A Methylomonas (strain GYJ3) isolated in our laboratory was identified as the type II methanotroph on the basis of the intractytoplasmic membrane of the ultrastructure . The optimal culture conditions for production of the soluble from of methane monooxygenase (MMO) were determined, in which the ratio of methane to air in atmosphere was 2 to 1 and Cu2+ concentration was 1.5 mumol/L . The biodegradation of trichoroethylene(TCE) by the resting cells of the strain GYJ3 was studied . All experiments were performed with cells grown under above conditions and thus expressing soluble MMO . This results showed that TCE at the high concentration of 30 mg/L did not inhibit to the enzymes in the cells . Addition of formate increased the initial specific TCE degradation rates . The product of TCE oxidation was found to be toxic to the cells . The degree of inactivation of MMO was proportional to the amount of TCE degraded . The TCE degradation capacities(Tc) of resting cells was determined . In no-formate and formate-fed experiments, the TCE degradation capacities were found to be 0.0778 and 0.0851 mg of TCE/mg of dry cell, respectively. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi, 1998 Jun, 15(2), 183 - 5 {Biodegradation and biocompatibility of a chitosan film}; Lu F et al.; The biodegradability and biocompatibility of a chitosan film were investigated in mice . The results showed that chitosan films had a mild inflammatory reaction in the early days of grafting, and after 16 weeks the inflammation basically subsided . Chitosan films were easily biodegraded . Chitosan is a novel natural absorbable medical film material and has a good developmental prospect. Hua Xi Yi Ke Da Xue Xue Bao, 2000 Sep, 31(3), 367 - 9 {Study on biodegradation of phenols in river water}; Zhao J et al.; This study on the biodegradation of phenols (phenol, o-methylphenol, o-chlorophenol and resorcinol) in river water was conducted by changing the main influential factors respectively . The results of experiment showed the phenols were greatly degradated in mild temperature, neutral pH and plenty of oxygen and the rank of the phenols biodegradation from great to small was resorcinol, phenol, o-methylphenol and o-chlorophenol . Presented in this paper is also a discussion on the biodegradation mechanism of phenols. J Ind Microbiol Biotechnol, 2003 Jan, 30(1), 70 - 4 Epub 2003 Jan 03. Degradation of polyvinyl alcohol by Sphingomonas sp . SA3 and its symbiote; Kim BC et al.; A total of 800 samples was taken from Taegu province, Korea, where many textile factories provide a source of polyvinyl alcohol (PVA) waste . These samples were screened for PVA-degrading bacteria . A new strain, SA3, was discovered which formed yellow colonies and used PVA as the sole carbon and energy source . Strain SA3 was identified as a Sphingomonas sp., based on the partial nucleotide sequence an