Mar Pollut Bull, 2004 Apr, 48(7-8), 671 - 8 Numerical simulation of organic chemicals in a marine environment using a coupled 3D hydrodynamic and ecotoxicological model; Kim DM et al.; For ecotoxicological risk assessment in a marine ecosystem, we constructed a coupled three-dimensional hydrodynamic and ecotoxicological model (EMT-3D), and applied it to Tokyo Bay . The model was calibrated with field data obtained in 2002 . The results of sensitivity analysis for dissolved Bisphenol A showed that biodegradation rate was the most important factor for concentration change . Bioconcentration coefficient was the most important factor for Bisphenol A in phytoplankton . Therefore, the parameters must be carefully considered in the modeling . The mass balance results showed that standing stocks of Bisphenol A in water, in particulate organic carbon and in phytoplankton are 7.85 x 10(4), 1.78 x 10(2) and 3.44 x 10(-1) g, respectively . With respect to flux, biodegradation in the water column had the highest value of 1.06 x 10(3) g/day, and next were effluent to the open sea, partition to particulate organic carbon, and bioconcentration in phytoplankton. Chemosphere, 2004 May, 55(6), 915 - 25 Biodegradation of haloacetic acids by bacterial enrichment cultures; McRae BM et al.; Haloacetic acids (HAAs) are toxic organic chemicals that are frequently detected in surface waters and in drinking water distribution systems . The aerobic biodegradation of HAAs was investigated in serum bottles containing a single HAA and inoculated with washed microorganisms obtained from enrichment cultures maintained on either monochloroacetic acid (MCAA) or trichloroacetic acid (TCAA) as the sole carbon and energy source . Biodegradation was observed for each of the HAAs tested at concentrations similar to those found in surface waters and in drinking water distribution systems . The MCAA culture was able to degrade both MCAA and monobromoacetic acid (MBAA) with pseudo-first order rate constants of 1.06 x 10(-2) and 1.13 x 10(-2) l(mg protein)(-1) d(-1), respectively, for concentrations ranging from 10(-5) to 2 mM . The pseudo-first order rate constant for TCAA degradation by the TCAA culture was 6.52 x 10(-3) l(mg protein)(-1) d(-1) for concentrations ranging from 5.33 x 10(-5) to 0.72 mM . The TCAA culture was also able to degrade MCAA with the rate accelerating as incubation time increased . Experiments with radiolabeled HAAs indicated that the 14C was primarily converted to 14CO2 with minor incorporation into cell biomass . The community structure of the enrichment cultures was analyzed by both cultivation-dependent and cultivation-independent approaches . Denaturing gradient gel electrophoresis (DGGE) of the PCR-amplified 16S rRNA gene fragments showed that each of the two enrichment cultures had multiple bacterial populations, none of which corresponded to HAA-degrading bacteria cultivated on HAA-supplemented agar plates . This research indicates that biodegradation is a potential loss mechanism for HAAs in surface waters and in drinking water distribution systems. Ground Water, 2004 Mar-Apr, 42(2), 258 - 67 Evaluation of volatilization as a natural attenuation pathway for MTBE; Lahvis MA et al.; Volatilization and diffusion through the unsaturated zone can be an important pathway for natural attenuation remediation of methyl tert-butyl ether (MTBE) at gasoline spill sites . The significance of this pathway depends primarily on the distribution of immiscible product within the unsaturated zone and the relative magnitude of aqueous-phase advection (ground water recharge) to gaseous-phase diffusion . At a gasoline spill site in Laurel Bay, South Carolina, rates of MTBE volatilization from ground water downgradient from the source are estimated by analyzing the distribution of MTBE in the unsaturated zone above a solute plume . Volatilization rates of MTBE from ground water determined by transport modeling ranged from 0.0020 to 0.0042 g m(-2)/year, depending on the assumed rate of ground water recharge . Although diffusive conditions at the Laurel Bay site are favorable for volatilization, mass loss of MTBE is insignificant over the length (230 m) of the solute plume . Based on this analysis, significant volatilization of MTBE from ground water downgradient from source areas at other sites is not likely . In contrast, model results indicate that volatilization coupled with diffusion to the atmosphere could be a significant mass loss pathway for MTBE in source areas where residual product resides above the capillary zone . Although not documented, mass loss of MTBE at the Laurel Bay site due to volatilization and diffusion to the atmosphere are predicted to be two to three times greater than mass loading of MTBE to ground water due to dissolution and recharge . This result would imply that volatilization in the source zone may be the critical natural attenuation pathway for MTBE at gasoline spill sites, especially when considering capillary zone limitations on volatilization of MTBE from ground water and the relative recalcitrance of MTBE to biodegradation. Environ Int, 2004 Jun, 30(4), 509 - 17 Phytodegradation of extra heavy oil-based drill cuttings using mature reed wetland: an in situ pilot study; Ji GD et al.; Environmental contamination caused by extra heavy oil-based drill cuttings (DCs) is a major problem in the Liaohe Oilfield, northeastern China . To study the potential effectiveness of the mature reed wetland in removing extra heavy oil contained in drill cuttings, biodegradation of extra heavy oils and study of the effects on soil property and ecophysiological and quality indices of reeds were carried out in a 2-year in situ pilot experiment . In the wetland, four reed beds were used to treat drill cuttings in various loadings: 0 (control), 5, 20, and 40 kg/m(2), corresponding to 150, 600, and 1200 g/m(2) extra heavy oil hydrocarbons (HCs) . The obtained results demonstrate that the mature reed wetland was effective at degrading extra heavy oils without extra fertilization . Removal efficiencies of reed bed 2 in the 0- to 80-cm soil profile increased with time, from 90.1% (first harvest season) to 95.8% (second harvest season) . After 2 years, only 4.2% of the initial hydrocarbons residual was retained in the surface soil . There was no apparent adverse effects on the surface soil property during degradation of extra heavy oils and, actually, the deeper soil property and reed quality indices were improved at the end of the experiment . Phytotoxicity, resulting in reduction of reed yield, was observed in the most heavily treated beds in the first year . However, long-term reed yield recovered robustly . During the 2-year period, reed height and leaf number were slightly inhibited. J Environ Sci Health A Tox Hazard Subst Environ Eng, 2004, 39(1), 1 - 17 Solid phase treatment of an aged soil contaminated by polycyclic aromatic hydrocarbons; Negri M et al.; Laboratory scale tests were carried out in order to evaluate the removal efficiency of polyaromatic hydrocarbons (PAHs) during the different biological treatments of a Manufacturing Gas Plant site aged soil, heavily contaminated by high molecular weight compounds . Biodegradation studies were carried out at nearly 25 degrees C in solid phase reactors . Three tests were performed, over a period of 100 days for each test . In the first test (P1-bioaugmentated), soil was mixed with wood chips and urea at the start of the treatment and after six weeks from the beginning of the test was also periodically inoculated (at 42, 54, 69, 82, and 96 days) with selected consortia of autochthonous PAH-degrading bacteria . The second test (P2-biostimulated) was performed similarly to the previous one, but without any inoculations . In the third test (P3-control) only soil was introduced . All systems were aerated daily and humidified at the occurrence . PAH concentration, total cultivable heterotrophs, PAH-degrading bacteria, mycetes, pH, ATP concentration, and enzymatic activities were monitored every two weeks during the treatments . Tests showed that nearly 50% of light (three rings) PAHs, 35% of benzo-PAHs and 40% of the total PAHs could be removed in the reactor P2 following 100 days of treatment . Lower removal efficiency could be observed for light PAHs (28%) in the inoculated reactor (P1) at the end of the treatment: comparable abatements were obtained for benzo- and total PAHs . In the reactor P3 (control), the concentration of all polyaromatic hydrocarbons was nearly always constant, suggesting that the physical losses were negligible during the solid phase treatments . Therefore the C to N ratio balance resulted to be the key factor in promoting the biodegradation process of all PAHs. Prikl Biokhim Mikrobiol, 2004 Jan-Feb, 40(1), 57 - 61 {Use of Panus tigrinus fungi for production of pressed materials from cotton plant waste}; Kadimaliev DA et al.; Changes in the chemical composition of cotton plant stems used as a substrate for solid-phase cultivation of the fungus Panus tigrinus were studied as well as the effect of these changes on properties of the pressed materials made of these stems . During the first 3 days of growth, the fungus better consumed cellulose; then, the rate of cellulose consumption was comparable with that of lignin . Intensity and pattern of these changes depended on the age of inoculum . The rate of cotton plant waste biodegradation was higher when a 3-day-old incoculum was used . The pressed materials made of the raw stuff treated with a 3-day-old inoculum of P . tigrinus for 2-3 days displayed better characteristics . Annually, large amounts of lignocellulose stuff is lost while processing of agricultural waste: straw, awn, plant stems, etc . In the countries with developed cotton growing, the annual amount of only guza-paya (dry cotton plant stems) reaches several million tons . To solve this problem, bioconversion of these wastes is studied to manufacture useful products and materials. J Contam Hydrol, 2004 Apr, 69(3-4), 173 - 94 Investigation of hydrogeologic processes in a dipping layer structure: 2 . Transport and biodegradation of organics; Alfnes E et al.; Numerical simulation tools have been used to study the dominating processes during transport of aromatic hydrocarbons in the unsaturated soil zone . Simulations were based on field observations at an experimental site located on a glacial delta plain with pronounced layered sedimentary structures . A numerical model for transport in the unsaturated zone, SWMS-3D, has been extended to incorporate coupled multispecies transport, microbial degradation following Monod kinetics and gas diffusive transport of oxygen and hydrocarbons . The flow field parameters were derived from previous work using nonreactive tracers . Breakthrough curves (BTC) from the hydrocarbon field experiment were used to determine sorption parameters and Monod kinetic parameters using a fitting procedure . The numerical simulations revealed that the assumption of homogeneous layers resulted in deviations from the field observations . The deviations were more pronounced with incorporation of reactive transport, compared with earlier work on nonreactive transport . To be able to model reasonable BTC, sorption had to be reduced compared to laboratory experiments . The initial biomass and the maximum utilisation rate could be adjusted to capture both the initial lag phase and the overall degradation rate . Nevertheless, local oxygen limitation is predicted by the model, which was not observed in the field experiment . Incorporation of evaporation and diffusive gas transport of the hydrocarbons did not significantly change the local oxygen demand . The main cause of the observed discrepancies between model and field are attributed to channelling as a result of small-scale heterogeneities such as biopores. J Biomater Sci Polym Ed, 2004, 15(1), 1 - 24 Biodegradation of amino-acid-based poly(ester amide)s: in vitro weight loss and preliminary in vivo studies; Tsitlanadze G et al.; A systematic in vitro biodegradation study of regular poly(ester amide)s (PEAs) composed of naturally occurring hydrophobic alpha-amino acids, fatty diols and dicarboxylic acids using gravimetric (weight loss) method was carried out in the presence of hydrolases like alpha-chymotrypsin, lipase and a complex of proteases of Papaya . The last enzyme was used for modeling the catalytic action of nonspecific proteases . It was found that the PEAs, in the presence of enzyme solutions, were biodegraded by surface chemical erosion mechanism, according to the first-order kinetics . Spontaneous immobilization (adsorption) of the enzymes onto the PEAs surfaces was observed . The surface immobilized enzyme can also catalyze the chemical erosion of the PEAs . The enzymes could also be impregnated into the PEAs to make PEAs biochemically biodegraded, i.e . 'self-destructive', at a target rate . A comparison of in vitro biodegradation data of the PEAs with polylactide (PDLLA) showed that PEAs exhibited a far more tendency toward enzyme catalyzed biodegradation than PDLLA . A preliminary in vivo biodegradation study of selected PEA films in rats with and without lipase-impregnation showed that those PEAs were completely absorbed within 1-2 months post-implantation (for the lipase-impregnated ones) and 3-6 months (for the lipase-free ones) . These findings prompt us to suggest that these new PEAs may have a great potential for designing drug sustained/controlled release devices, as well as implantable surgical devices. J Environ Sci Health A Tox Hazard Subst Environ Eng, 2004, 39(2), 409 - 20 Enhancement of carbon and nitrogen transformations during composting of municipal solid waste; Abu Qdais HA et al.; Appropriate management of municipal solid waste (MSW) is viewed as an integrated system encompassing waste minimization, recycling, and resource recovery . This has increased the interest in the composting process, in which the biodegradable portion of MSW is biologically converted into a valuable product that can be utilized as a soil conditioner or fertilizer . Effective operation of the composting process can be achieved by determining the optimal conditions for the controlling parameters in order to enhance the biological reactions during composting . Information on biodegradation rates are also essential for process design . Therefore, this study was conducted in order to examine the factors affecting process performance and transformation of essential elements of MSW such as carbon and nitrogen . A pilot study of in-vessel aerobic composting of MSW was carried out and the operating parameters, which affect biodegradation of carbonaceous and nitrogenous matter were studied using a specially designed rotating drum and a carbon-rich MSW . The effects of temperature, moisture content, and air flow rate were examined . The performance of the composting process was evaluated by measuring the carbon and nitrogen content during experiments, each of which lasted for 30 days . The study showed that enhanced transformations of carbon and nitrogen occur at 55 degrees C for temperature, 60% for moisture content, and 10L/kgh for air flow rate using the food-rich MSW generated in the Gulf countries. J Environ Sci Health A Tox Hazard Subst Environ Eng, 2004, 39(2), 351 - 64 Assessment of Kuwait's Al-Qurain landfill using remotely sensed data; Kwarteng AY et al.; Kuwait's Al-Qurain landfill problem resulted from indiscriminate dumping of domestic and industrial waste in an abandoned quarry in the late 1970s and early 1980s . The landfill and surrounding areas were set aside for a government housing project without an environmental assessment of the impact of the landfill on the project . Inhabitants of the newly constructed housing area experienced persistent foul odor emanating from the landfill site . Since then, the issue has generated a lot of public interests, and several remediation measures have been adopted . In this preliminary study, several remotely sensed data consisting of Landsat Multispectral Scanner (MSS), Landsat Thematic Mapper (TM), IKONOS, and synthetic aperture radar (SAR) acquired between 1972 and 2000 were processed and assessed for their usefulness to study and monitor the landfill site . The imagery provided a historical perspective of how the areas had changed over the last 30 years . Other useful information of the landfill obtained from the satellite imagery included the spatial extent, spectral reflectance, surface temperature, and surface roughness . The landfill site showed higher surface temperatures compared to the immediate surrounding areas-a process that could accelerate the biodegradation and the release of landfill gases . Such dataset could be incorporated into a GIS for the long-term monitoring of the site. Biomaterials, 2004 Aug, 25(17), 3359 - 68 Effects of periodate and chondroitin 4-sulfate on proteoglycan stabilization of ostrich pericardium . Inhibition of calcification in subcutaneous implants in rats; Arenaz B et al.; Chemical modification of biological materials used in the manufacture of cardiac valves tends to reduce the relatively high degree of biodegradation and calcification of the implanted bioprostheses . The most widely used treatment to reduce biodegradability of the valves is glutaraldehyde fixation . However, this treatment is potentially toxic and induces tissue calcification . In order to minimize these undesirable effects, we have analyzed the effect of a pre-fixation of endogenous proteoglycans and exogenous glycosaminoglycans, as well as the borohydride reduction influence on the different modified ostrich pericardium implants after subcutaneous implantation in rats . The presence of calcific deposits was detected in all implanted GA-fixed samples; however, calcification was highly reduced in both groups of periodate-prefixed materials, which showed also a very low Ca/P molar ratio . Borohydride post-treatment of these biomaterials resulted in a significant increase in calcium phosphate precipitation, with the appearance of calcium deposits mainly in an amorphous form even though X-ray diffraction allowed the detection of brushite- and apatite-like crystals . Regarding tissue stability, no significant differences were found among the borohydride-untreated implants but higher levels of matrix metalloproteinases were observed by gelatin zymography in the periodate pre-fixed materials . This increase was partially reduced by pre-fixation of exogenous chondroitin 4-sulfate . On the other hand, borohydride post-treatment not only increased calcification, but also reduced tissue stability and increased the presence of matrix-degrading activities. Curr Microbiol, 2004 Jan, 48(1), 10 - 3 Biodegradation of DDT by a Pseudomonas species; Kamanavalli CM et al.; A bacterial strain capable of degrading 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) was isolated from insecticide-contaminated soil by biphenyl enrichment culture and identified as a Pseudomonas species . The organism degraded DDT through the intermediate formation of 2,3-dihydroxy-DDT, which undergoes meta-ring cleavage, ultimately yielding 4-chlorobenzoic acid as a stable metabolite. Water Res, 2004 Mar, 38(6), 1595 - 603 Assessment of enhancement in biodegradation of dichlorodiethyl ether (DCDE) by pre-oxidation; Kaludjerski M et al.; The objective of this study is to assess the enhancement in biodegradation of dichlorodiethyl ether (DCDE) by ozonation and Fenton treatment . Acclimated and non-acclimated sludge cultures were used to test the biodegradability of the preoxidized DCDE solutions by three different tests: Short-term and long-term respirometry through continuous monitoring of oxygen consumption, and the mid-term test in which the amount of remaining organic matter was measured by TOC and COD tests . These tests were applied to solutions of DCDE preoxidized at the levels of 25%, 50%, 75%, and 100% . The results indicated that the biodegradability of oxidized DCDE solutions improved substantially compared to non-oxidized solutions . Fenton-treated DCDE exhibited toxicity to microorganisms under long-term exposure . Higher levels of preoxidation of DCDE led to mineralization of larger amounts of organic matter during subsequent biodegradation . There was no significant difference in the rate of biodegradation of oxidized products by either acclimated or non-acclimated bacteria. Shanghai Kou Qiang Yi Xue, 2000 Jun, 9(2), 73 - 5 {Experimental Study of Mandibular Reconstruction With Sr-HAP}; Liao DP et al.; OBJECTIVE:Different ration of Sr-HAP was implanted in animals to study the bioreactions in order to prepare for the clinical applications in future . METHODS:24 rabbits were divided into 3 groups for study.Bone defect of 6x12x4mm was made at the mandibular angle of rabbits and Sr-HAP of different proportion(10%,5%,0%) was applied to repair the defect.One group of animals were killed at 1 month, 3 months, 6 months to evaluate the biologic capacity with anatomy, tetracycline fluorescent marker and ration histology.RESULTS:Sr-HAP almost hadn't been rejected by hosts,and early after operation the new bone in the Sr-HAP was found with great quantities as the degradation of Sr-HAP much more than that in the pure HA,and the difference of bone quantity can be shown in statistics.New bone in 5% Sr-HAP looked more mature than those in 10% Sr-HAP with no statistic difference in quantity.Strong and bright fluorescent rings can be seen around Sr-HAP from the 3 months to 6 months . CONCLUSION:(1) Sr-HAP has a better biocompatibility,biodegradation than pure HA and an excellent osteoinductivity . (2) The ration of strontium isn't the key influencing the new bone quantity,total new bone quantity maybe associated with the degree of biodegradation . (3)The existence of Sr-HAP improves the total new bone quantity and prolongs the period of new bone increasing. J Control Release, 2004 Feb 20, 95(1), 1 - 26 Genetically engineered polymers: status and prospects for controlled release; Haider M et al.; Genetic engineering methodology has enabled the synthesis of protein-based polymers with precisely controlled structures . Protein-based polymers have well-defined molecular weights, monomer compositions, sequences and stereochemistries . The incorporation of tailor-made motifs at specified locations by recombinant techniques allows the formation of hydrogels, sensitivity to environmental stimuli, complexation with drugs and nucleic acids, biorecognition and biodegradation . Accordingly, a special interest has emerged for the use of protein-based polymers for controlled drug and gene delivery, tissue engineering and other biomedical applications . This article is a review of genetically engineered polymers, their physicochemical characteristics, synthetic strategies used to produce them and their biomedical applications with emphasis on controlled release. Tissue Eng, 2004 Jan-Feb, 10(1-2), 73 - 80 In vitro and in vivo degradation of mineralized collagen-based composite scaffold: nanohydroxyapatite/collagen/poly(L-lactide); Liao SS et al.; The objective of this article was to investigate the in vitro and in vivo biodegradation of a novel biomimetic bone scaffold composite, nanohydroxyapatite/collagen/poly(L-lactide), that could be used for bone tissue engineering . For evaluation of in vitro degradation specimens were immersed into 1% trypsin/phosphate-buffered saline solution at 37 degrees C . In vivo evaluation involved the implantation of samples into the posterolateral lumbar spine of rabbits, and the retrieved specimens were analyzed by Fourier transform-infrared spectroscopy . The results demonstrated that weight loss increased continuously in vitro with a reduction in mass of 19.6% after 4 weeks . During the experimental period in vitro, the relative rate of reduction of the three components in this material was shown to differ greatly: collagen decreased the fastest, from 40% by weight to 20% in the composite; hydroxyapatite content increased from 45 to 60%; and PLA changed little . The pore structure was maintained throughout the whole experimental period in vitro; however, the thickness of the walls of the pores decreased and the surface of the walls increased in roughness . In vivo, the ratio of collagen to hydroxyapatite appeared to be slightly higher near the transverse process than in the central part of the intertransverse process . This finding may have been due to new bone matrix formation extending from the transverse to the intertransverse process. Chemosphere, 2004 Apr, 55(4), 525 - 31 Uncertainty analysis of parameters for modeling the transfer and fate of benzo(a)pyrene in Tianjin wastewater irrigated areas; Wang XL et al.; A Monte Carlo simulation for uncertainty analysis of three key parameters (local coal consumption rate Q(1L), dry deposition velocity of aerosol particulate Kp and biodegradation rate of benzo(a)pyrene in soil and sediment K(R3)) was conducted in this study . Results of the simulation indicate that the three parameters were influenced by uncertainty and that all equilibrium concentrations in the four bulk compartments and various sub-compartments were log-normally distributed . However, the results also indicated that among the six primary transfer fluxes, erosion associated with solids in soil and deposition associated with solids in water, along with output from sewers were also log-normally distributed, while deposition from air to soil and biodegradation in soil and sediment followed normal distributions . The effect of uncertainty on the model results of the three key parameters was derived using a comparison of upper and lower of confidence interval boundaries at the 95% level of confidence . The results reveal that uncertainty in the key parameters had a more significant influence on equilibrium concentrations of the chemical in the bulk compartments of soil and sediment than on concentrations in the other two bulk compartments, various sub-compartments and the six predominant transfer fluxes. Arch Oral Biol, 2004 Apr, 49(4), 305 - 11 Effect of glutaraldehyde on the humoral immunogenicity and structure of porcine dermal collagen membranes; Wu KJ et al.; OBJECTIVES: Our previous studies showed that the biodegradation rate of cross-linked porcine dermal collagen membrane (PDCM) could be retarded without changing its biocompatible character . The purpose of this study was to assay the humoral immune response of PDCM reconstitute with glutaraldehyde (GA) and observe their surface architectures . METHODS: PDCM reconstituted with GA (0, 0.01, 0.05, and 3%) was implanted in 30 Sprague-Dawley rats . Sample sera were collected 3, 6, and 9 weeks after surgery and assayed with ELISA . The architectures of PDCMs were observed under SEM (100x) . RESULTS: The study showed that non cross-linked PDCM induced the highest immune response than any other cross-linked PDCMs (by optical density (OD) values, P<0.05) . It also possessed the most active cross-reactivity to the serum of rats from any other PDCMs groups (by Sheffe test, P<0.05) . The surface architectures observed under SEM presented four structures: fibrillar, porous, channeled, and sheet-like structures as PDCM was conditioned with 0, 0.01, 0.05, and 3% GA, respectively . CONCLUSIONS: Resulting from the study are that changing the concentration of GA can modulate the surface characters of PDCMs and change their immunogenicity . Reconstitution of PDCM may not change the conformation of antigenic determinants of PDCM but rather hinder the epitopes by changing the surface stereo structure of this collagen. Biomacromolecules, 2004 Mar-Apr, 5(2), 596 - 602 Biodegradation of chemically modified flax fibers in soil and in vitro with selected bacteria; Modelli A et al.; The extent and rate of degradation of flax (Linum usitatissimum) fibers, both in the native state and after surface chemical modification (acetylation or poly(ethylene glycol), PEG, grafting), was investigated under laboratory conditions in two different biodegrading environments . Degradation of the fibers under aerobic conditions by the action of the microorganisms present in soil is assessed with the ASTM 5988-96 method by monitoring carbon dioxide evolution . In vitro biodegradation experiments were carried out by exposing the fibers to a pure culture of Cellvibrio fibrovorans bacteria and measuring the mass loss as a function of time . Despite the complexity of the system, the results of degradation in soil were satisfactorily reproducible, although the absolute rates were found to change in different experiments using the same soil . The degradation rate of acetylated fibers in soil nearly equals that of unmodified fibers, whereas in the pure culture, acetylated fibers biodegrade slower than native fibers . The opposite happens with the PEG-grafted fibers, which degrade slower than unmodified flax in soil and at a comparable rate upon in vitro exposure to the bacterial culture . The different biodegradation kinetics observed in the two biodegrading environments were attributed to differences of biocenoses, abiotic factors, and biodegradation assessing methods . Nevertheless, the final extent of biodegradation was the same for modified and unmodified fibers both in soil and in the pure culture, showing that the surface chemical modifications applied do not significantly affect biodegradability of the flax fibers. Environ Sci Technol, 2004 Feb 15, 38(4), 1009 - 16 Aerobic biodegradation of two commercial naphthenic acids preparations; Clemente JS et al.; Naphthenic acids (NAs) have a variety of commercial uses including as emulsifiers and wood preservatives . They have been identified as being the main component responsible for the acute toxicity in produced waters in the oil sands operations in northeastern Alberta, Canada . NAs comprise a complex mixture of alkyl-substituted acyclic and cycloaliphatic carboxylic acids, with the general chemical formula CnH(2n+Z)O2, where n indicates the carbon number and Z specifies hydrogen deficiency from ring formation . In this study, commercial preparations of NAs were shown to be degraded in aerobic cultures from oil sands process-affected waters . High-performance liquid chromatography and gas chromatography-mass spectrometry (GC-MS) were used to monitor the concentrations and composition of the NA mixtures during biodegradation . Within 10 days of incubation, the NAs concentrations dropped from about 100 to <10 mg/L . This was accompanied by the release of about 60% of carbon from the NAs as CO2 and the reduction of toxicity of the culture supernatant, as measured by the Microtox assay . GC-MS results demonstrated that biodegradation changes the composition of the complex mixture of these NAs and that the lower molecular weight acids (with n = 5-13) were degraded more readily than the high molecular weight acids. J Agric Food Chem, 2004 Mar 10, 52(5), 1220 - 3 Biodegradation of beta-cyfluthrin by fungi; Saikia N et al.; Five fungal species, namely, Trichoderma viride strain 5-2, T . viride strain 2211, Aspergillus niger, A . terricola, and Phanerochaete chrysoporium were screened for degradation study of beta-cyfluthrin . Each fungal species was allowed to grow in Czapek dox medium containing beta-cyfluthrin (5 mg/mL) as the major carbon source of the medium . The highest degradation of beta-cyfluthrin was observed by T . viride 5-2 (T(1/2) = 7.07 days), followed by T.viride 2211 (T(1/2) = 10.66 days) . The degradation of beta-cyfluthrin followed first-order kinetics with a fast degradation rate during first 7 days of growth of the fungi . In the case of T . viride strain 5-2, five degradation products were isolated after 20 days of growth of the fungi, out of which three products were identified as alpha-cyano-4-fluorobenzyl-3- (2,2-dichlorovinyl)-2,2-dimethyl cyclopropane carboxylate, alpha-cyano-4-fluoro-3-phenoxy benzyl alcohol, and 3(2,2-dichlorovinyl)-2,2-dimethyl cyclopropanoic acid. Chemosphere, 2004 Apr, 55(3), 389 - 94 Novel method for determining pyrene biodegradation using synchronous fluorimetry; Zhang Y et al.; To study the biodegradation rate of pyrene dissolved in liquid medium supplemented with mineral salts, a synchronous fluorimetry (SF) method was established . The limit of detection for pyrene dissolved in mineral salts medium (MSM) was determined as 0.19 ng/ml with a relative standard deviation of less than 1.3% (n = 9) . The pyrene degrading rates of four bacterial strains were investigated using this method under the same experimental conditions . The degradation rates of the three active strains ranged from 76% to 87% after a 14-h incubation . The results were confirmed by the gas chromatography with a flame ionized detector (GC/FID) method . This implies that pyrene degradation can be directly monitored by the SF method without the solvent extraction of samples . The advantages of SF are that it is less laborious, faster, and less expensive than the GC/FID determination method with solvent extraction . The SF method provides a new tool for studying the degradation of polynuclear aromatic hydrocarbons (PAHs) in the natural environment and under experimental conditions. Chemosphere, 2004 Apr, 55(3), 379 - 88 Biological and photochemical degradation rates of diethylenetriaminepentaacetic acid (DTPA) in the presence and absence of Fe(III); Metsarinne S et al.; The environmental fate of ethylenediaminetetraacetic acid (EDTA) has been extensively studied, while much less is known about the environmental behaviour of diethylenetriaminepentaacetic acid (DTPA) . In this study, it was confirmed that DTPA is persistent toward biodegradation . The biodegradability of DTPA was investigated in the absence and in the presence of Fe(III) by using CO2 evolution test and Manometric respirometry test . The CO2 evolution and oxygen uptake of iron-free (DTPA was added as free acid) and Fe(III)DTPA were less than in inoculum blank . Possible inhibitor effect was analysed by testing biodegradation of sodium benzoate with and without iron-free or Fe(III)DTPA in the Manometric respirometry test . Only slight inhibition was observed when DTPA was added as free acid . Photodegradation of iron-free DTPA and Fe(III)-DTPA complex was studied by using sunlight and UV radiation at the range 315-400 nm emitted by black light lamps . The results indicate that DTPA added as free acid degrades photochemically in humic lake water . Fe(III)DTPA was shown to be very photolabile in humic lake water in the summer; the photochemical half-life was below one hour . Photodegradation products were identified by the mass spectrometric technique (GC-MS) . It was shown that photodegradation of Fe(III)DTPA does not result in total mineralization of the compound . Diethylenetriaminetetraacetic acid, diethylenetriaminetriacetic acid, ethylenediaminetriacetic acid, N,N'- and/or N,N-ethylenediaminediacetic acid, iminodiacetate, ethylenediaminemonoacetic acid and glycine were identified as photodegradation products of Fe(III)DTPA . Based on these observations, we propose a photodegradation pathway for Fe(III)DTPA. Environ Pollut, 2004 May, 129(2), 277 - 88 Attenuation reactions in a multiple contaminated aquifer in Bitterfeld (Germany); Heidrich S et al.; Large-scale contaminated sites with multiple contaminants in the groundwater present a challenge to risk assessment and remediation . Attenuation reactions take place in the subsurface and act to contain contaminants, but must be thoroughly investigated on a site-specific basis . Field data from monitoring wells at a contaminated industrial site in Bitterfeld, Germany, are presented and analyzed for evidence of the prevalent biodegradation reactions . The groundwater in the Tertiary aquifer is contaminated with large quantities of chlorinated aliphatic compounds, in addition to chlorobenzenes and BTEX . In this strictly anaerobic environment, geochemical indications for several microbial processes were found, including methanogenesis, sulfate and iron reduction as well as reductive dechlorination of the chlorinated hydrocarbons . Direct evidence for the latter degradation reaction was observed along the flowpath due to the appearance of intermediates and an increase in the degree of dechlorination. Environ Toxicol Chem, 2004 Feb, 23(2), 313 - 24 Enhancing the attenuation of explosives in surface soils at military facilities: combined sorption and biodegradation; Fuller ME et al.; This research evaluated soil amendments designed to enhance the adsorption and biodegradation of explosives at military training facilities, thus minimizing their potential for transport to subsurface environments . Several carbon cosubstrates were tested in soil slurries for their ability to stimulate the biodegradation of 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (royal demolition exposive {RDX}), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (high-melting explosive {HMX}) by indigenous soil microorganisms . Crude soybean oil and molasses stimulated mineralization of RDX (30-40%) and HMX (approximately 10%) . The TNT was not significantly mineralized in any of the treatments, but high-performance liquid chromatography (HPLC) analysis indicated extensive transformation of TNT to amino-containing compounds . The biodegradation of explosives was then examined in unsaturated soil microcosms amended with crude soybean oil and molasses combined with sphagnum peat moss and sawdust . Minimal TNT mineralization was observed, and HMX mineralization was only observed with molasses addition . In contrast, RDX mineralization was extensive in microcosms amended with soybean oil or molasses . The presence of peat moss decreased soybean oil-stimulated RDX mineralization by approximately 5%, but resulted in about 5% greater RDX mineralization compared with molasses only . Sawdust markedly decreased mineralization regardless of cosubstrate type . Mass balance results indicated that the formation of bound residues likely was occurring, especially for TNT . These results indicate that the application of inexpensive adsorbents and cosubstrates to soils may significantly improve the protection of groundwater resources underlying live fire ranges. Water Sci Technol, 2004, 49(1), 53 - 9 Influence of the origin of the inoculum on the anaerobic biodegradability test; Moreno-Andrade I et al.; Five different sources of inocula were studied to determine its influence on biodegradability tests . Inocula were characterized determining granulometry, specific methanogenic activity, solids content, and volumetric sludge index . Also, the fermentative, aceticlastic, hydrogenophilic, OPHA, and sulfate-reducing groups were determined by the most probable number technique . Anaerobic biodegradability tests were conducted with two different substrates, one easy to degrade (glucose) and a toxic one (phenol) . The best performance, in terms of percent of biodegradation and lag time, for both substrates, was obtained with the inoculum from a brewery industry UASB . The results can be explained in terms of the initial activity of the inoculum . The influence of the significant variations found in the specific methanogenic activity of the five inocula studied is discussed, in terms of the microbial composition of the samples . The results emphasized the importance of the selection of an appropriate source of inoculum in order to obtain reliable results. J Cell Physiol, 2004 Apr, 199(1), 8 - 19 Changes in macrophage function and morphology due to biomedical polyurethane surfaces undergoing biodegradation; Matheson LA et al.; Monocytes are recruited to the material surface of an implanted biomedical device recognizing it as a foreign body . Differentiation into macrophages subsequently occurs followed by fusion to form foreign body giant cells (FBGCs) . Consequently, implants can become degraded, cause chronic inflammation or become isolated by fibrous encapsulation . In this study, a relationship between material surface chemistry and the FBGC response was demonstrated by seeding mature monocyte-derived macrophages (MDMs) on polycarbonate-based polyurethanes that differed in their chemical structures (synthesized with poly(1,6-hexyl 1,2-ethyl carbonate) diol, and either (14)C-hexane diisocyanate and butanediol (BD) (referred to as HDI) or 4,4'-methylene bisphenyl diisocyanate and (14)C-BD (referred to as MDI)) and material degradation assessed . At 48 h of cell-material interaction, the FBGC attached to HDI were more multinucleated (73%) compared to MDI or the polystyrene (PS) control (21 and 36%, respectively) . There was a fivefold increase in the synthesis and secretion of a protein with an approximate molecular weight of 48 kDa and a pI of 6.1 (determined by two-dimensional gel electrophoresis) only from cells seeded on HDI . Immunoprecipitation confirmed that MSE and CE were synthesized and secreted de novo . Immunoblotting also showed an increase in secreted monocyte-specific esterase (MSE) and cholesterol esterase (CE) from cells seeded on HDI relative to PS and MDI . Significantly more radiolabel ((14)C) release and esterase activity were elicited by MDMs on HDI than MDI (P < 0.05) . The material that was more degradable (HDI), elicited greater protein synthesis and esterase secretion as well as more multinucleated MDMs than MDI, suggesting that the material surface chemistry modulates the function of MDM at the site of an inflammatory response to an implanted device . Biodegradation, 2004 Feb, 15(1), 29 - 39 Potential for aerobic and anaerobic biodegradation of petroleum hydrocarbons in boreal subsurface; Salminen JM et al.; We studied the role of aerobic and anaerobic petroleum hydrocarbon degradation at a boreal, light-weight fuel and lubrication oil contaminated site undergoing natural attenuation . At the site, anoxic conditions prevailed with high concentrations of CH4 (up to 25% v/v) and CO2 (up to 18% v/v) in the soil gas throughout the year . Subsurface samples were obtained mainly from the anoxic parts of the site and they represented both the unsaturated and saturated zone . The samples were incubated in microcosms at near in situ conditions (i.e . in situ temperature 8 degrees C, aerobic and anaerobic conditions, no nutrient amendments) resulting in the removal of mineral oil (as determined by gas chromatography) aerobically as well as anaerobically . In the aerobic microcosms on average 31% and 27% of the initial mineral oil was removed during a 3- and 4-month incubation, respectively . In the anaerobic microcosms, on average 44% and 15% of the initial mineral oil was removed during a 12- and 10-month anaerobic incubation, respectively, and e.g . n-alkanes from C11 to C15 were removed . A methane production rate of up to 2.5 microg CH4 h(-1) g(-1) dwt was recorded in these microcosms . In the aerobic as well as anaerobic microcosms, typically 90% of the mineral oil degraded belonged to the mineral oil fraction that eluted from the gas chromatograph after C10 and before C15, while 10% belonged to the fraction that eluted after C15 and before C40 . Our results suggest that anaerobic petroleum hydrocarbon degradation, including n-alkane degradation, under methanogenic conditions plays a significant role in the natural attenuation in boreal conditions. J Environ Sci (China), 2004, 16(1), 132 - 7 Evaluation of fungal potentiality for bioconversion of domestic wastewater sludge; Alam MZ et al.; This study was undertaken to screen the filamentous fungi isolated from its relevant habitats(wastewater, sewage sludge and sludge cake) for the bioconversion of domestic wastewater sludge . A total of 35 fungal strains were tested against wastewater sludge (total suspended solids, TSS 1%-5% w/w) to evaluate its potentiality for enhancing the biodegradability and dewaterability using liquid state bioconversion(LSB) process . The strains were divided into five groups i.e . Penicillium, Aspergillus, Trichoderma, Basidiomycete and Miscellaneous, respectively . The strains WWZP1003, SCahmA103, SCahmT105 and PC-9 among their respective groups of Penicillium, Aspergillus, Trichoderma and Basidiomycete played potential roles in terms of separation (formation of pellets/flocs/filaments), biodegradation(removal of COD) and filtration (filterability) of treated domestic wastewater sludge . The Miscellaneous group was not considered due to its unsatisfactory results as compared to the other groups . The pH value was also influenced by the microbial treatment during fermentation process . The filterability of treated sludge was improved by fungal treatment, and lowest filtration time was recorded for the strain WWZP1003 and SCahmA103 of Penicillium and Aspergillus groups respectively compared with other strains. Biotechnol Lett, 2003 Dec, 25(24), 2089 - 92 Epifluorescence microscope methods for bacterial enumeration in a 4-chlorophenol degrading consortium; Pacheco CC et al.; Epifluorescence microscope methods, namely BacLight, direct epifluorescence filter technique and Rhodamine 123, consistently underestimated plate bacterial counts in a 4-chlorophenol degrading consortium . Cells capable of passing through 0.2 microm filters, referred as 'ultramicrocells', were found . Although cell counts were higher when traditional methods were used, BacLight and direct epifluorescence filter technique were convenient techniques for the systematic monitoring of bacteria involved in biodegradation processes, as results were consistent and available within a short time. Biomaterials, 2004 Jul, 25(15), 2997 - 3004 Enhanced biological stability of collagen porous scaffolds by using amino acids as novel cross-linking bridges; Ma L et al.; Collagen porous scaffolds have been widely employed as a dermal equivalent to induce fibroblasts infiltration and dermal regeneration . To eliminate the disadvantageous drawback of the fast degradation speed, a cross-linking method was adopted by using a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDAC) and N-hydroxysuccinimide (NHS) in the presence of amino acids (glycin, glutamic acid or lysine), which function as cross-linking bridge between collagen molecular chains . In vitro assessment of the biological stability of the cross-linked collagen scaffolds found that the collagenase biodegradation degree was greatly decreased when lysine was added, resulting in a more biological stable scaffold . On the other hand, the biodegradation degree was accelerated compared with the purely cross-linked when glutamic acid was added, while less influenced by glycin addition . By comparing the biodegradation degree of the scaffolds added with amino acids and their model compounds, i.e . adipic acid and hexane diamine, the key factor influencing the biological stability was further investigated . The results indicated that the crucial factor is dependent on the ratio of amino groups to carboxyl groups in the cross-linking system . At optimal ratio the lowest biodegradation degree is achieved . Scanning electron microscopy measurements prove that the three-dimensional structure of the scaffolds was largely preserved . Preliminary in vitro culture of fibroblasts in the collagen scaffold cross-linked with EDAC/NHS in the presence of lysine has shown that the original good cytocompatibility of collagen was retained. Biotechnol Bioeng, 2004 Mar 20, 85(6), 580 - 8 Biodegradation kinetics of volatile hydrophobic organic compounds in cultures with variable fractional volumes; Tien TH et al.; An extension of the models developed by Guha and Jaffe (Biotechnol Bioeng {1996} 50:693-699) to describe the phenanthrene biodegradation kinetics for the cultures with variable fractional volumes is presented . Batch experiments were conducted with a culture capable of degrading the phenanthrene using a single culture vessel from which samples were withdrawn over time to monitor the disappearance of phenanthrene . For accurate measurement of phenanthrene concentrations, a sampling procedure designed for quantifying the sorption of phenanthrene onto glassware was also introduced . The Monod parameters were estimated by nonlinear regression analyses of simultaneous solutions to the substrate utilization/volatilization and Monod equations for growth of the cell mass . The results demonstrate that the models were able to be extended to phenanthrene-degrading cultures with variable fractional volumes . When the ratio between sampling volume and volume of the culture medium was relatively small, the parameters obtained were similar to those which would be obtained using constant fractional volumes of culture medium . It was also found that the model's fit to the phenanthrene disappearance data in this study were better than those obtained by Guha and Jaffe, implying that the sorption process of phenanthrene during the sampling period could significantly affect the measurement of phenanthrene concentrations . Failing to account for these losses led to less accurate measurements of substrate concentrations, which in turn resulted in a poor estimation of the parameters . The findings of this study reduce considerably the experimental work necessary in the estimation of Monod kinetic parameters for the purpose of modeling . FEMS Microbiol Lett, 2004 Feb 9, 231(1), 13 - 7 Characterization of a novel carbofuran degrading Pseudomonas sp . with collateral biocontrol and plant growth promoting potential; Bano N et al.; The isolate NJ-101 obtained from agricultural soil was characterized and presumptively identified as Pseudomonas sp . The isolate exhibited efficient degradation of the insecticide carbofuran with a rate constant of 0.035 day(-1), following first-order rate kinetics . The ability of performing multifarious biological activities in tandem suggested the uniqueness of isolate NJ-101 . The ability to produce hydrogen cyanide and siderophore stipulated its role in biological control . Furthermore, the growth inhibition of Fusarium sp . validated the antagonistic activity of NJ-101 against the common phytopathogens . Concurrent production of indole acetic acid, and solubilization of inorganic phosphate revealed its plant growth promoting potential . Thus, the innate capability of this novel isolate for parallel biodegradation, biocontrol and plant growth promotion has significance in management of the agro-environmental and phytopathological problems. Acta Pharm, 2003 Sep, 53(3), 187 - 97 Biodistribution of 131I-BSA loaded gelatin microspheres after peroral application to BALB/c mice--particle size study; Mladenovska K et al.; Biodistribution studies of radiolabelled 131I-BSA loaded gelatin microspheres were carried out on BALB/c mice after peroral administration . To two groups, radiolabelled 131I-BSA gelatin microspheres of different particle size, 1.2 +/- 1.1 microm and 7.0 +/- 1.2 microm, were administered orally . To the control group, a solution of 131I-BSA was administered orally as well . Biodistribution was followed periodically within 15 days as the percent of total radioactivity present in the stomach and small intestine with Peyer's patches and mesentery, in colon with Peyer's patches, appendix and mesentery, in liver, spleen, blood, kidney, lungs and heart . Preliminary in vitro biodegradation and drug release studies confirmed the potential of gelatin microspheres to protect the antigen of interest from enzymatic degradation in the gut, and to release it in a controlled manner . The biodistribution data confirmed that particle uptake into Peyer's patches and passage to the liver and spleen via the mesentery lymph supply and nodes increased with decreasing particle size. Appl Environ Microbiol, 2004 Feb, 70(2), 1023 - 30 Induction of methyl tertiary butyl ether (MTBE)-oxidizing activity in Mycobacterium vaccae JOB5 by MTBE; Johnson EL et al.; Alkane-grown cells of Mycobacterium vaccae JOB5 cometabolically degrade the gasoline oxygenate methyl tertiary butyl ether (MTBE) through the activities of an alkane-inducible monooxygenase and other enzymes in the alkane oxidation pathway . In this study we examined the effects of MTBE on the MTBE-oxidizing activity of M . vaccae JOB5 grown on diverse nonalkane substrates . Carbon-limited cultures were grown on glycerol, lactate, several sugars, and tricarboxylic acid cycle intermediates, both in the presence and absence of MTBE . In all MTBE-containing cultures, MTBE consumption occurred and tertiary butyl alcohol (TBA) and tertiary butyl formate accumulated in the culture medium . Acetylene, a specific inactivator of alkane- and MTBE-oxidizing activities, fully inhibited MTBE consumption and product accumulation but had no other apparent effects on culture growth . The MTBE-dependent stimulation of MTBE-oxidizing activity in fructose- and glycerol-grown cells was saturable with respect to MTBE concentration (50% saturation level = 2.4 to 2.75 mM), and the onset of MTBE oxidation in glycerol-grown cells was inhibited by both rifampin and chloramphenicol . Other oxygenates (TBA and tertiary amyl methyl ether) also induced the enzyme activity required for their own degradation in glycerol-grown cells . Presence of MTBE also promoted MTBE oxidation in cells grown on organic acids, compounds that are often found in anaerobic, gasoline-contaminated environments . Experiments with acid-grown cells suggested induction of MTBE-oxidizing activity by MTBE is subject to catabolite repression . The results of this study are discussed in terms of their potential implications towards our understanding of the role of cometabolism in MTBE and TBA biodegradation in gasoline-contaminated environments. J Bone Joint Surg Br, 2004 Jan, 86(1), 120 - 5 Biodegradation and biocompatability of a calcium sulphate-hydroxyapatite bone substitute; Nilsson M et al.; An injectable material consisting of calcium sulphate mixed with hydroxyapatite was investigated as a possible alternative to autograft in the restoration of bone defects . The material was studied both in vitro in simulated body fluid (SBF) and in vivo when implanted in rat muscles and into the proximal tibiae of rabbits . Variation in the strength and weight of the material during ageing in SBF was measured . Tissue response, material resorption and bone ingrowth were studied in the animal models . A good tissue response was observed in both the rat muscles and rabbit tibiae without inflammatory reactions or the presence of fibrous tissue . Ageing in SBF showed that during the first week carbonated hydroxyapatite precipitated on the surfaces of the material and this may enhance bone ingrowth. Appl Microbiol Biotechnol, 2004 Jun, 64(5), 702 - 11 Epub 2004 Feb 05. Quinone-respiration improves dechlorination of carbon tetrachloride by anaerobic sludge; Cervantes FJ et al.; The impact of humic acids and the humic model compound, anthraquinone-2,6-disulfonate (AQDS), on the biodegradation of carbon tetrachloride (CT) by anaerobic granular sludge was studied . Addition of both humic acids and AQDS at sub-stoichiometric levels increased the first-order rate of conversion of CT up to 6-fold, leading to an increased production of inorganic chloride, which accounted for 40-50% of the CT initially added . Considerably less dechlorination occurred in sludge incubations lacking humic substances . By comparison, very limited dechlorination occurred in sterile controls with autoclaved sludge . Accumulation of chloroform (1-10%) and dichloromethane (traces) also accounted for the CT converted . The accumulation of a chlorinated ethene, perchloroethylene (up to 9% of added CT), is also reported for the first time as an end-product of CT degradation . A humus-respiring enrichment culture (composed primarily of a Geobacter sp.) derived from the granular sludge also dechlorinated CT, yielding products similar to the AQDS-supplemented granular sludge consortium . The dechlorination of CT by the Geobacter enrichment was dependent on the presence of AQDS or humic acids, which were reduced during the assays . The reduced form of AQDS, anthrahydroquinone-2,6-disulfonate, was shown to cause the chemical reduction of CT when incubated in sterile medium . The results taken as a whole indicate that the formation of reduced humic substances by quinone-respiring microorganisms can contribute to the reductive dechlorination of CT. Waste Manag, 2004, 24(2), 127 - 37 Field trial of a new aeration system for enhancing biodegradation in a biopile; Li L et al.; The influence of a new aeration system on the biopile performance was investigated . The purpose was to increase biodegradation efficiency by optimising airflow through the pile . During a 1-month field trial, the performance of a new system using two perforated vertical pipes with wind-driven turbines was compared with that of a standard pile configuration with two horizontal perforated pipes . Both piles were composed of a similar mix of diesel-contaminated soils, woodchips, compost and NPK fertiliser . Hydrocarbons were recovered using solvent extraction, and determined both gravimetrically and by gas chromatography . Total heterotrophs, pH and moisture content were also assessed . Air pressure measurements were made to compare the efficiency of suction in the pipes . Results at the end of the experiment showed that there was no significant difference between the two piles in the total amount of hydrocarbon biodegradation . The normalised degradation rate was, however, considerably higher in the new system than in the standard one, suggesting that the vertical venting method may have improved the efficiency of the biological reactions in the pile . The pressure measurements showed a significant improvement in the suction produced by the new aeration system . However, many factors other than the airflow (oxygen supply) may influence and limit the biodegradation rates, including moisture content, age of contaminants and the climatic conditions . Additional experiments and modelling need to be carried out to explore further the new aeration method and to develop criteria and guidelines for engineering design of optimal aeration schemes in order to achieve maximum biodegradation in biopiles. Appl Microbiol Biotechnol, 2004 Aug, 65(3), 330 - 5 Epub 2004 Feb 03. Reductive transformation of methyl parathion by the cyanobacterium Anabaena sp . strain PCC7120; Barton JW et al.; Organophosphorus compounds are toxic chemicals that are applied worldwide as household pesticides and for crop protection, and they are stockpiled for chemical warfare . As a result, they are routinely detected in air and water . Methods and routes of biodegradation of these compounds are being sought . We report that under aerobic, photosynthetic conditions, the cyanobacterium Anabaena sp . transformed methyl parathion first to o,o-dimethyl o-p-nitrosophenyl thiophosphate and then to o,o-dimethyl o-p-aminophenyl thiophosphate by reducing the nitro group . The process of methyl parathion transformation occurred in the light, but not in the dark . Methyl parathion was toxic to cyanobacteria in the dark but did not affect their viability in the light . Methyl parathion transformation was not affected by mutations in the genes involved in nitrate reduction in cyanobacteria. Biotechnol Bioeng, 2004 Mar 5, 85(5), 561 - 7 Thermal and enzymatic pretreatment of sludge containing phthalate esters prior to mesophilic anaerobic digestion; Gavala HN et al.; The present study aimed at investigating the effect of thermal pretreatment of sludge at 70 degrees C on the anaerobic degradation of three commonly found phthalic acid esters (PAE): di-ethyl phthalate (DEP), di-butyl phthalate (DBP), and di-ethylhexyl phthalate (DEHP) . Also, the enzymatic treatment at 28 degrees C with a commercial lipase was studied as a way to enhance PAE removal . Pretreatment at 70 degrees C of the sludge containing PAE negatively influenced the anaerobic biodegradability of phthalate esters at 37 degrees C . The observed reduction of PAE biodegradation rates after the thermal pretreatment was found to be proportional to the PAE solubility in water: the higher the solubility, the higher the percentage of the reduction (DEP > DBP > DEHP) . PAE were slowly degraded during the pretreatment at 70 degrees C, yet this was probably due to physicochemical reactions than to microbial/biological activity . Therefore, thermal pretreatment of sludge containing PAE should be either avoided or combined with a treatment step focusing on PAE reduction . On the other hand, enzymatic treatment was very efficient in the removal of PAE . The enzymatic degradation of DBP, DEP, and DEHP could be one to two orders of magnitude faster than under normal mesophilic anaerobic conditions . Moreover, the enzymatic treatment resulted in the shortest half-life of DEHP in sludge reported so far . Our study further showed that enzymatic treatment with lipases can be applied to raw sludge and its efficiency does not depend on the solids concentration . Res Microbiol, 2004 Jan-Feb, 155(1), 1 - 9 Molecular cloning, nucleotide sequencing and expression of genes encoding a cytochrome P450 system involved in secondary amine utilization in Mycobacterium sp . strain RP1; Trigui M et al.; Mycobacterium sp . strain RP1 degrades morpholine, piperidine, and pyrrolidine and is able to use these compounds as the sole source of carbon, nitrogen, and energy . Cytochrome P450 (MorA) is involved in the biodegradation of these secondary amines . A 3.9-PstI genomic DNA fragment, containing the gene encoding MorA, was cloned and sequenced . Four open reading frames were detected on this DNA fragment . The first encoded a cytochrome P450 designated as MorA which was the second member of the CYP151 family and was named CYP151A2 . The second open reading frame (morB) featured a {3Fe-4S} type of ferredoxin . A third gene (morC), exhibiting sequence identity to known reductases, and a fourth truncated gene encoding a putative glutamine reductase (orf1' ), were found downstream of morB . Recombinant MorA cytochrome P450 was purified to homogeneity from Escherichia coli . The purified enzyme was a monomeric soluble protein with an apparent Mr of about 45,000 . CYP151A2 catalyzed the ring cleavage of the secondary amines and the Vmax/KMapp values indicated that pyrrolidine is the preferred substrate for this monooxygenase. Ecotoxicol Environ Saf, 2004 Feb, 57(2), 162 - 7 Residual toxicity after biodegradation: interactions among benzene, toluene, and chloroform; da Silva Nunes-Halldorson V et al.; A microbial enrichment originating from a pristine aquifer was found to aerobically biodegrade benzene and toluene, but not chloroform . This enrichment culture was used to study changes in pollutant toxicity as affected by biodegradative activity . Two assays for toxicity were used: (1) a 48-h acute toxicity test using the freshwater invertebrate Ceriodaphnia dubia and (2) microbial biodegradation activity as affected by the presence of mixed pollutants . At 20-ppm concentrations, toluene was significantly more toxic (99% mortality) to C . dubia than benzene (48% mortality) or chloroform (40% mortality) . Also at 20-ppm concentrations, but before biodegradation, toluene was significantly more toxic (88% mortality) to C . dubia than benzene (33% mortality) . After biodegradation of 98% of toluene and benzene, significant residual toxicity still remained in the bacterial supernatant: toluene-degraded supernatant caused 33% mortality in C . dubia and benzene-degraded supernatant caused 24% mortality . In the second toxicity assay, examining the effect of mixed pollutants on biodegradation activity, the presence of benzene slowed the biodegradation of toluene, but chloroform had no effect on either benzene or toluene biodegradation . Results indicate that significant toxicity remain after biodegradation and that halogenated aliphatic hydrocarbons may have little or no effect on aromatic hydrocarbon biodegradation at sites impacted by mixed pollutants. Biomaterials, 2004 Jun, 25(13), 2687 - 93 Enzymatic degradation of starch-based thermoplastic compounds used in protheses: identification of the degradation products in solution; Araujo MA et al.; Apart from favourable physico-chemical and mechanical properties, the most important requirement for a biodegradable polymer to be used in medical applications is its biocompatibility and the non-cytotoxicity of its degradation products . Their combined effect should assure the safe material degradation under controlled kinetics . The present work analyses the degradation behaviour of blends of corn starch with poly(ethylene-vinyl alcohol) copolymer (SEVA-C) . The characterization included long-term degradation trials on simulated physiological solution with alpha-amylase up to 200 days . The degradation solutions were analysed by several techniques . High-performance liquid chromatography (HPLC) and colorimetric methods were used to monitor the liberation of carbohydrate as a consequence of starch hydrolysis by alpha-amylase . The hydration degree was followed by thermogravimetric analysis (TGA) . Several degradation products such as carbohydrates ranging from C6 to C18 were identified . After alpha-amylase action, biodegradation was more pronounced in the first 100 days, after which the biodegradation rate decreased probably due to the structure and porosity of the material . The action of alpha-amylase solely led to the starch degradation, in contrast with other assays without enzymes where no carbohydrates were found in the degradation solutions. Biochem Biophys Res Commun, 2004 Feb 20, 314(4), 957 - 63 Anaerobic transformation of 2,4,6-TNT by bovine ruminal microbes; Fleischmann TJ et al.; Degradation of TNT by bovine rumen fluid, a novel source of anaerobic microbes, was investigated . Whole rumen fluid contents were spiked with TNT and incubated for a 24h time period . Supernatant samples taken at 0, 1, 2, 4, and 24h were analyzed by reverse-phase HPLC with diode array detection . Within 1h, TNT was not detectable and reduction products of TNT including 2-hydroxyl-amino-4,6-dinitrotoluene, 4-hydroxylamino-2,6-dinitrotoluene, and 4-amino-2,6-dinitrotoluene were present with smaller amounts of diamino-nitrotoluenes . Within 2h, only the diamino and dihydroxyamino-nitrotoluene products remained . After 4h, 2,4-diamino-6-nitrotoluene and 2,4-dihydroxyamino-6-nitrotoluene were the only known molecular species left . At 24h known UV absorbing metabolites were no longer detected, suggesting further transformation such as complete reduction to triaminotoluene or destruction of the aromatic ring of TNT may have occurred . TNT was not transformed at 24h in autoclaved and buffered controls . This study presents the first direct evidence of biodegradation of TNT by ruminal microbes. Environ Sci Technol, 2004 Jan 15, 38(2), 609 - 16 Hydrogen and carbon isotope fractionation during anaerobic biodegradation of aromatic hydrocarbons--a field study; Steinbach A et al.; The aquifer of a former manufactured gas plant site, highly contaminated by dissolved monocyclic, heterocyclic, and polycyclic aromatic hydrocarbons, was studied to evaluate the applicability of carbon and hydrogen isotope fractionation to prove ongoing biodegradation of these compounds even in complex aquifer settings . The loss of toluene, o-xylene, p,m-xylene, and 2-methylnaphthalene was accompanied by a considerable carbon isotope fractionation . Additionally, a strong 2H enrichment in residual o-xylene was detected . All isotope fractionations observed could be related to established biochemical degradation mechanisms, each involving a C-H bond cleavage in the rate-determining step . In contrast, other compounds such as 1-methylnaphthalene, methylbenzofuran, and acenaphthene exhibited a uniform stable carbon isotope composition . However, a decrease in concentration for these compounds was observed in the flowpath of the aquifer . High threshold concentrations of acenaphthene downgradient indicate that this contaminant is, if at all, only marginally biodegraded . Detailed analyses of xylenes provided support that compound specific isotope analyses and subsequent application of the Rayleigh model may provide a valuable basis to distinguish between different biodegradation mechanisms as well as dissolution processes in heterogeneous aquifers. Ann Bot (Lond), 2004 Mar, 93(3), 249 - 61 Epub 2004 Jan 28. The function of the superficial root mat in the biogeochemical cycles of nutrients in congolese eucalyptus plantations; Laclau JP et al.; BACKGROUND AND AIMS: The importance of superficial root mats inside the forest floor for the nutrition of Amazonian rain forests has been extensively investigated . The present study was aimed at assessing the function of a root mat adherent to decomposing organic material observed in Eucalyptus plantations . METHODS: The development of the root mat was studied through micromorphological observations of thin litter sections, and the influence of soil microtopography and soil water repellency on root mat biomass was assessed in situ on an area of 5 m2 . In addition, input-output budgets of nutrients within the forest floor were established from measurements of litterfall, dissolved nutrients in gravitational solutions, and forest floor nutrient contents . KEY FINDINGS: The amounts of nutrients released during litter decay in this ecosystem during the period of study were, on average, 46, 3, 4, 19 and 17 kg ha-1 year-1 for N, P, K, Ca and Mg, respectively . The simultaneous measurements of the chemical composition of throughfall solutions and leachates beneath the forest floor showed a very quick uptake of nutrients by the root mat during the decomposition processes . Indeed, the solutions did not become noticeably enriched in nutrients during their passage through the holorganic layer, despite large amounts of elements being released during litter decay . The root mat biomass decreased significantly during the dry season, and a preferential development in microdepressions at the soil surface was observed . A strong water repellency observed in these depressions might enhance the ability of the roots to take up water and nutrients during the dry periods . CONCLUSIONS: The root mat was active throughout the year to catch the flux of nutrients from the biodegradation of the forest floor, preventing the transfer of dissolved nutrients toward deeper soil horizons . This mechanism is involved in the successful adaptation of this Eucalyptus hybrid in areas covered by 'climacic' savannas in Congo. Int J Syst Evol Microbiol, 2004 Jan, 54(Pt 1), 131 - 9 Pseudonocardia chloroethenivorans sp . nov., a chloroethene-degrading actinomycete; Lee SB et al.; A bacterial strain, SL-1T, capable of degrading trichloroethene was isolated from a laboratory enrichment in the Department of Civil and Environmental Engineering, University of Washington, USA . The material in the enrichments was derived from a soil sample from Seattle, WA, USA . Strain SL-1T was capable of using phenol as a source of carbon and energy . Chemotaxonomic, morphological, physiological and phylogenetic analyses showed that strain SL-1T is a member of the genus Pseudonocardia . The ability of strain SL-1T to utilize phenol and degrade trichloroethene, as well as other phenotypic properties and the results from a 16S rRNA phylogenetic analysis, led to the proposal of a novel species, Pseudonocardia chloroethenivorans sp . nov . The type strain is SL-1T (=ATCC BAA-742T=DSM 44698T) . Trichloroethene and other chloroethenes are major pollutants at many environmental sites, and P . chloroethenivorans has biodegradation properties that should be of interest to environmental microbiologists and engineers. Biomaterials, 2004 May, 25(12), 2309 - 17 Preparation and characteristics of hybrid scaffolds composed of beta-chitin and collagen; Lee SB et al.; Hybrid scaffolds composed of beta-chitin and collagen were prepared by combining salt-leaching and freeze-drying methods . The chitin scaffold used as a framework was easily formed into desired shapes with a uniformly distributed and interconnected pore structure with average pore size of 260-330 microm . The mechanical strength and the rate of biodegradation increased with the porosity, which could be modulated by the salt concentration . In addition, atelocollagen solution was introduced into the macropores of the chitin scaffold to improve cell attachment . Web-like collagen fibers fabricated between pores of chitin were produced by a 0.1 wt% collagen solution, whereas a 0.5 wt% collagen solution only coated the surface of the chitin scaffold . After 3 days of culture, fibroblasts cultured in collagen-coated scaffolds were attached at the place where the collagen was fabricated, whereas cells did not attach and aggregate on the scaffold of chitin alone . After 14 days, the fibroblasts showed a good affinity to and proliferation on all collagen-coated chitins. Biomaterials, 2004 May, 25(10), 1787 - 93 Mutual influence of cholesterol esterase and pseudocholinesterase on the biodegradation of dental composites; Finer Y et al.; It has been demonstrated that human saliva contains cholesterol esterase (CE)- and pseudocholinesterase (PCE)-like hydrolase activities . While PCE has been shown to preferentially degrade triethylene glycol dimethacrylate (TEGDMA) and its derivatives, CE has a greater catalytic effect on the breakdown of bis-phenol-A-diglycidyl dimethacrylate (bisGMA) components in composite dental resins . The current study seeks to determine if there is a mutual influence between the different esterases with respect to the biodegradation of resin composite . Photopolymerized model composite resin samples (containing 60% by weight fraction of silanated barium glass filler) based on bisGMA/TEGDMA (bis) or urethane-modified bisGMA/TEGDMA/bisEMA (ubis) monomers were incubated in buffer, CE and/or PCE solutions (pH=7.0, 37 degrees C) for 8 and 16 days . The incubation solutions were analyzed for degradation products using high-performance liquid chromatography, UV spectroscopy and mass spectrometry . In the bis system, higher amounts (p<0.05) of a bisGMA derived product, bishydroxy-propoxyphenyl-propane (bisHPPP), were detected in the combined enzyme group as compared to the sum of the two individual enzyme groups . In the ubis system, similar comparisons showed that higher levels (p<0.05) of bisHPPP were detected in the combined group at 8 days while higher amounts (p<0.05) of a bisEMA derived product, ethoxylated bis-phenol A, were detected in the combined group at 16 days . The study concluded that CE and PCE act synergistically to increase the biodegradation of both composite resin materials. J Chromatogr A, 2003 Dec 22, 1021(1-2), 11 - 7 Isolation of poly(propylene glycol)s from water for quantitative analysis by reversed-phase liquid chromatography; Rychlowska J et al.; Procedures for the isolation of poly(propylene glycol)s (PPGs) from a water matrix have been developed . Solid-phase extraction with an octadecylsilica cartridge and elution with methanol or with a graphitised carbon black cartridge and elution with a mixture of dichloromethane-methanol (4:1) or liquid-liquid extraction with chloroform were all suitable for model samples . However, only liquid-liquid extraction was suitable both for model and real environmental samples . Methods for reversed-phase liquid chromatographic determination of PPGs based on derivatisation and ultraviolet or fluorescence detection have been developed . Four derivatisation agents {3,5-dinitrobenzoyl chloride, phenyl isocyanate, 1-naphthoyl chloride and 1-naphthyl isocyanate (NIC)} were tested . Only NIC was found to give good reproducibility as well as a satisfactory detection limit . Finally, a method with liquid-liquid extraction with chloroform, derivatisation with NIC and liquid chromatographic separation with fluorescence detection was established . The developed method shows a highly correlated linearity of the analytical signals of particular homologues within a wide concentration range (approximately from 0.01 to 10 mg l(-1)) . The precision of measurements is satisfactory for homologues having 5-9 oxypropylene subunits and becomes worse with an increase in the number of oxypropylene subunits . The limit of detection is 2 microg l(-1) for the majority of homologues . The method is suitable for the isolation and quantitative determination of PPGs in river water samples and as a tool for biodegradation testing. Aviakosm Ekolog Med, 2003, 37(5), 70 - 3 {Development of a technology for biodegradation of plant wastes in order to resolve the life support requirements of a Martian expedition}; Il'in VK et al.; A two-phase technology has been developed for biodegradation of plant wastes . On the first phase, wastes are subjected to anaerobic fermentation by specially selected microbial associations processing solid wastes into a liquid mixture of organic acids . On the second phase, methanogenic bacteria are used to produce biogas out of the liquid, which then can be dumped out into open space or utilized as a cold propellant. Chin J Traumatol, 2004 Feb, 7(1), 18 - 24 Effect of nano-hydroxyapatite/collagen composite and bone morphogenetic protein-2 on lumbar intertransverse fusion in rabbits; Sun TS et al.; OBJECTIVE: To investigate the effect of nano-hydroxyapatite/collagen (nHA/collagen) composite as a graft extender and enhancer when combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) on lumbar intertransverse fusion in rabbits . METHODS: Sixty-four adult female New Zealand white rabbits, aged 1 year and weighing 3.5-4.5 kg, underwent similar posterolateral intertransverse process arthrodesis and were randomly divided into 4 groups based on different grafts: autogenous cancellous bone alone (ACB group), nHA/collagen alone (HAC group), half autogenous cancellous bone and half nHA/collagen (ACB+HAC group) and nHA/collagen combined with rhBMP-2 (HAC+BMP group) . The fusion masses were analyzed by manual palpation, radiography, biomechanical testing and histological examination . RESULTS: Fusion was observed in 4 cases in the 6th week and in 5 cases in the 10th week after surgery in ACB group . No case showed fusion in HAC group . In ACB+HAC group, there was fusion in 3 cases in the 6th week and in 4 cases in the 10th week after surgery . In HAC+BMP group, fusion in 1 case was found in the 4th week, in 5 cases in the 6th week and in 6 cases in the 10th week after surgery . It suggested that ACB, ACB+HAC and HAC+BMP groups showed similar fusion ratio and mechanical strength in the 6th and 10th week after surgery . According to the microstructure analysis of the samples, nHA/collagen had no negative effect when implanted together with ilium autograft . In HAC+BMP group, new bone-like tissue was observed in the 2nd week postoperatively, and nearly all of the implanted composites were replaced by mature bone matrix and new bones in 10th week postoperatively . CONCLUSIONS: The nHA/collagen, especially combined with rhBMP-2, is a promising bone substitute, for it has quick biodegradation, fine bone-bending ability, and high osteoconductivity on posterolateral spinal fusion in rabbits. Appl Microbiol Biotechnol, 2004 Jun, 64(5), 712 - 7 Epub 2004 Jan 16. Biodegradation of alachlor by soil streptomycetes; Duraes Sette L et al.; Streptomycetes resistant to the herbicide alachlor {2-chloro-2',6'-diethyl- N-(methoxymethyl) acetanilide} were used in degradation assays to characterize the products of alachlor biodegradation . Of six strains tested, Streptomyces sp . LS166, LS177, and LS182 were able to grow at an alachlor concentration of 144 mg l(-1) and degraded approximately 60-75% of the alachlor in 14 days, as evaluated by high performance liquid chromatography . The alachlor biodegradation products were identified by gas chromatography-mass spectrometry based on mass spectral data and fragmentation patterns . All compounds detected in these assays were similar for all streptomycetes strains tested, and involved dechlorination with subsequent N-dealkylation and cyclization of the remaining N-substituent with one of the ethyl groups to produce indole and quinoline derivatives . The enzymatic pathway used by Streptomyces sp . LS182 did not generate DEA (2',6'-diethylaniline), a carcinogenic derivative of alachlor reported in other studies . Given the high degradation rates observed here, the Streptomyces strains tested may be useful in the degradation/detoxification processes of alachlor. Anal Chem, 2004 Jan 15, 76(2), 399 - 403 Quenched phosphorescence as a detection method in capillary electrophoretic chiral separations . Monitoring the stereoselective biodegradation of camphorquinone by yeast; Garcia-Ruiz C et al.; Quenched phosphorescence detection of camphorquinone in cyclodextrin-based electrokinetic chromatography provides very favorable detection limits, i.e., 7 x 10(-)(7) M, 3 orders of magnitude lower than conventional UV absorption detection at 200 nm . The detection is based on the dynamic quenching by the analyte of the strong phosphorescence emission of brominated naphthalenesulfonate, under deoxygenated buffer solution conditions . This approach has been used to detect (1S)-(+)- and (1R)-(-)-camphorquinone after enantiomeric separation by CE . Although the use of the negatively charged carboxymethyl beta-cyclodextrin (CM-beta-CD) alone was not successful, the addition of a second, neutral cyclodextrin, alpha-CD, provided an adequate enantiomeric separation of camphorquinone . Using 25 mM borate buffer (pH 8.5) with 10 mM CM-beta-CD and 20 mM alpha-CD (applied voltage 20 kV, ambient temperature), the enantiomeric separation was performed in approximately 14 min . The chiral method was applied to monitor the stereoselectivity of the biotransformation of a racemic mixture of camphorquinone by yeast . It was found that the enantiomeric ratio calculated from the peak areas in the electropherogram (RSD = 5%) after 24 h of incubation decreased from 0.92 for the control solution (culture medium without yeast) to 0.24 for the culture medium; a similar ratio of 0.25 was observed for cell extract solutions . Therefore, racemic camphorquinone is enantioselectively degraded by yeast, the biodegradation of (1S)-(+)-camphorquinone being faster than that of the (1R)-(-)-enantiomer. Biotechnol Lett, 2003 Nov, 25(22), 1905 - 11 Salicylate biodegradation by various algal-bacterial consortia under photosynthetic oxygenation; Munoz R et al.; Four green microalgae (Chlorella sorokiniana, Chlorella vulgaris, Scenedesmus obliquus and Selenastrum capricornutum), a wild Bolivian microalga strain and two cyanobacteria (Anabaena catenula and Microcystis aeruginosa) were compared for tolerance to salicylate, O2 production capacity and ability to support salicylate degradation by a Ralstonia basilensis strain in symbiotic microcosms with the microalgae . Microcystis aeruginosa had the highest tolerance to salicylate at 500 mg l(-1) and 1500 mg l(-1) but only produced 0.7 mg O2 l(-1) h(-1) in the absence of pollutant . Chlorella sorokiniana resisted salicylate at 1500 mg l(-1) with the highest O2 production in the absence of salicylate (26 mg l(-1) h(-1)) closely followed by the Bolivian microalga (23 mg l(-1) h(-1)) and Chlorella vulgaris (21 mg l(-1) h(-1)) . Selenastrum capricornutum and Anabaena catenula were completely inhibited by salicylate at 500 mg l(-1) . When inoculated with Ralstonia sp . and supplied with salicylate, Chlorella sorokiniana had the highest removal rate (19 mg l(-1) h(-1)), followed by the wild Bolivian strain (18 mg l(-1) h(-1)) and Chlorella vulgaris (14 mg l(-1) h(-1)). Sheng Wu Yi Xue Gong Cheng Xue Za Zhi, 2003 Dec, 20(4), 746 - 9 {Studies on a kind of new biodegradable material--polycaprolactone and developments in medical area}; Zhang N et al.; Nowadays, there are more and more researches on characters and applications of polycaprolactone (PCL) . This paper reviews the researches of polycaprolactone, including its synthesis, physical and chemical properties, biodegradation, absorption properties, and its applications in clinical use and drug delivery systems . PCL can be from open ring polymerizaion . It is a kind of semi-crystalline polymer, and has good flexibility . The degradation reaction of PCL is hydrolysis . PCL is not cumulated in the body, and can be totally excreted . It can be used as suture, material for fixation of bone fracture, vector of drug, etc . PCL is widely used in medical area because of its safety, low toxicity, biodegradability. Appl Microbiol Biotechnol, 2004 Jan, 63(4), 460 - 5 Epub 2003 Mar 26. Bioavailability of pentachlorophenol to acclimatised bacteria under batch and flow-through conditions; Dudal Y et al.; Biodegradation of organic contaminants in multi-phase systems, such as soils and aquifers, is often limited by the extent and the rate of contaminant sorption onto the solid matrix . However, information about biodegradation in complex matrices is largely limited to studies of closed systems under batch conditions in which potential bioavailability is characterised by the aqueous-phase concentration of a contaminant . There is little knowledge regarding the influence of flow-through conditions on the availability of contaminants to microbes (contaminant bioavailability) . Thus, the aim of this study was to assess and compare contaminant bioavailability, in the presence of a sorptive medium, under both batch and flow-through conditions . Accordingly, experiments were designed in which pentachlorophenol (PCP) was introduced into a mixture of inoculated silica sand and a PCP-retaining resin, under either batch or flow-through (columns) conditions . The results indicated that an increase in the amount of resin (0.1-0.2 g) clearly lowered PCP availability to microbes after 170 h under batch conditions (30 and 45% respectively); whereas, the initial decrease in bioavailability observed under flow-through conditions (45 and 70% respectively) was reversed and no longer observable after 170 h . This increase in PCP availability was linked to an improvement in the contaminant biodegradation capacity from 0.03 to 0.13 mg x l(-1) x h(-1) over 200 h. Appl Microbiol Biotechnol, 2004 Apr, 64(3), 317 - 25 Epub 2004 Jan 10. Microbial P450 enzymes in biotechnology; Urlacher VB et al.; Oxidations are key reactions in chemical syntheses . Biooxidations using fermentation processes have already conquered some niches in industrial oxidation processes since they allow the introduction of oxygen into non-activated carbon atoms in a sterically and optically selective manner that is difficult or impossible to achieve by synthetic organic chemistry . Biooxidation using isolated enzymes is limited to oxidases and dehydrogenases . Surprisingly, cytochrome P450 monooxygenases have scarcely been studied for use in biooxidations, although they are one of the largest known superfamilies of enzyme proteins . Their gene sequences have been identified in various organisms such as humans, bacteria, algae, fungi, and plants . The reactions catalyzed by P450s are quite diverse and range from biosynthetic pathways (e.g . those of animal hormones and secondary plant metabolites) to the activation or biodegradation of hydrophobic xenobiotic compounds (e.g . those of various drugs in the liver of higher animals) . From a practical point of view, the great potential of P450s is limited by their functional complexity, low activity, and limited stability . In addition, P450-catalyzed reactions require a constant supply of NAD(P)H which makes continuous cell-free processes very expensive . Quite recently, several groups have started to investigate cost-efficient ways that could allow the continuous supply of electrons to the heme iron . These include, for example, the use of electron mediators, direct electron supply from electrodes, and enzymatic approaches . In addition, methods of protein design and directed evolution have been applied in an attempt to enhance the activity of the enzymes and improve their selectivity . The promising application of bacterial P450s as catalyzing agents in biocatalytic reactions and recent progress made in this field are both covered in this review. J Pharm Pharmacol, 2003 Nov, 55(11), 1451 - 63 The potential of chitosan in ocular drug delivery; Alonso MJ et al.; This paper presents an overview of the potential of chitosan-based systems for improving the retention and biodistribution of drugs applied topically onto the eye . Besides its low toxicity and good ocular tolerance, chitosan exhibits favourable biological behaviour, such as bioadhesion- and permeability-enhancing properties, and also interesting physico-chemical characteristics, which make it a unique material for the design of ocular drug delivery vehicles . The review summarizes the techniques for the production of chitosan gels, chitosan-coated colloidal systems and chitosan nanoparticles, and describes their mechanism of action upon contact with the ocular mucosa . The results reported until now have provided evidence of the potential of chitosan gels for enhancing and prolonging the retention of drugs on the eye surface . On the other hand, chitosan-based colloidal systems were found to work as transmucosal drug carriers, either facilitating the transport of drugs to the inner eye (chitosan-coated colloidal systems containing indometacin) or their accumulation into the corneal/conjunctival epithelia (chitosan nanoparticles containing ciclosporin) . Finally, the tolerance, toxicity and biodegradation of the carriers under evaluation were reviewed. Appl Environ Microbiol, 2004 Jan, 70(1), 508 - 17 Biodegradation of nitro-substituted explosives 2,4,6-trinitrotoluene, hexahydro-1,3,5-trinitro-1,3,5-triazine, and octahydro-1,3,5,7-tetranitro-1,3,5-tetrazocine by a phytosymbiotic Methylobacterium sp . associated with poplar tissues (Populus deltoides x nigra DN34); Van Aken B et al.; A pink-pigmented symbiotic bacterium was isolated from hybrid poplar tissues (Populus deltoides x nigra DN34) . The bacterium was identified by 16S and 16S-23S intergenic spacer ribosomal DNA analysis as a Methylobacterium sp . (strain BJ001) . The isolated bacterium was able to use methanol as the sole source of carbon and energy, which is a specific attribute of the genus Methylobacterium . The bacterium in pure culture was shown to degrade the toxic explosives 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazene (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5-tetrazocine (HMX) . {U-ring-(14)C}TNT (25 mg liter(-1)) was fully transformed in less than 10 days . Metabolites included the reduction derivatives amino-dinitrotoluenes and diamino-nitrotoluenes . No significant release of (14)CO(2) was recorded from {(14)C}TNT . In addition, the isolated methylotroph was shown to transform {U-(14)C}RDX (20 mg liter(-1)) and {U-(14)C}HMX (2.5 mg liter(-1)) in less than 40 days . After 55 days of incubation, 58.0% of initial {(14)C}RDX and 61.4% of initial {(14)C}HMX were mineralized into (14)CO(2) . The radioactivity remaining in solution accounted for 12.8 and 12.7% of initial {(14)C}RDX and {(14)C}HMX, respectively . Metabolites detected from RDX transformation included a mononitroso RDX derivative and a polar compound tentatively identified as methylenedinitramine . Since members of the genus Methylobacterium are distributed in a wide diversity of natural environments and are very often associated with plants, Methylobacterium sp . strain BJ001 may be involved in natural attenuation or in situ biodegradation (including phytoremediation) of explosive-contaminated sites. Appl Environ Microbiol, 2004 Jan, 70(1), 324 - 31 Differential stress-induced regulation of two quinone reductases in the brown rot basidiomycete Gloeophyllum trabeum; Cohen R et al.; Quinone reductases (QRDs) have two important functions in the basidiomycete Gloeophyllum trabeum, which causes brown rot of wood . First, a QRD is required to generate biodegradative hydroxyl radicals via redox cycling between two G . trabeum extracellular metabolites, 2,5-dimethoxyhydroquinone (2,5-DMHQ) and 2,5-dimethoxy-1,4-benzoquinone (2,5-DMBQ) . Second, because 2,5-DMBQ is cytotoxic and 2,5-DMHQ is not, a QRD is needed to maintain the intracellular pool of these metabolites in the reduced form . Given their importance in G . trabeum metabolism, QRDs could prove useful targets for new wood preservatives . We have identified two G . trabeum genes, each existing in two closely related, perhaps allelic variants, that encode QRDs in the flavodoxin family . Past work with QRD1 and heterologous expression of QRD2 in this study confirmed that both genes encode NADH-dependent, flavin-containing QRDs . Real-time reverse transcription PCR analyses of liquid- and wood-grown cultures showed that qrd1 expression was maximal during secondary metabolism, coincided with the production of 2,5-DMBQ, and was moderately up-regulated by chemical stressors such as quinones . By contrast, qrd2 expression was maximal during fungal growth when 2,5-DMBQ levels were low, yet was markedly up-regulated by chemical stress or heat shock . The total QRD activity in lysates of G . trabeum mycelium was significantly enhanced by induction beforehand with a cytotoxic quinone . The promoter of qrd2 contains likely antioxidant, xenobiotic, and heat shock elements, absent in qrd1, that probably explain the greater response of qrd2 transcription to stress . We conclude from these results that QRD1 is the enzyme G . trabeum routinely uses to detoxify quinones during incipient wood decay and that it could also drive the biodegradative quinone redox cycle . However, QRD2 assumes a more important role when the mycelium is stressed. Microb Ecol, 2003 Aug, 46(2), 145 - 60 Epub 2003 Jul 04. Microbial community responses to atrazine exposure and nutrient availability: linking degradation capacity to community structure; Rhine ED et al.; Repeated pesticide exposure may enhance biodegradation through selective enrichment of pesticide-metabolizing microorganisms, particularly when the compound is used as a C and energy source . The relationship between pesticide application history and degradation rate is unclear when the chemical is utilized as a nutrient source other than C . Atrazine, a poor source of C and energy, was chosen as a model compound because it can serve as an N source for some microorganisms . Soils with (H-soil) and without (NH-soil) prior s-triazine treatment history were repeatedly exposed to atrazine and a variety of C and N source amendments . Exposure to atrazine and inorganic-N availability were the dominant factors leading to the development of microbial communities with an enhanced capacity to degrade atrazine . The density of the atrazine-degrading microorganisms increased immediately, up to 1000-fold, with atrazine exposure in the H-soil, but comparable increases were not observed in the NH-soil until 12 weeks following laboratory acclimation, despite high rates of atrazine mineralization in these soils immediately following the acclimation period . Whole-soil fatty acid methyl ester (FAME) analysis showed that the application of alternative C and N sources in addition to atrazine resulted in a microbial community composition that was distinctly different from that in either the atrazinealone treatment or water controls for both the H- and NH-soils . These data suggest that the microbial communities in both soils were altered differently in response to the treatments but developed a similar enhanced capacity to mineralize atrazine. Ann Chim, 2003 Nov, 93(11), 889 - 96 Fungal colonization on stoneworks . Interaction fungi-powdered stone samples; Sbaraglia G et al.; The microbial activity plays an important role in the biodegradative processes implied in stonework decay . In natural environments it is not possible to separate the damage produced by microorganisms from damage caused by physical and chemical agents . In vitro assays carried out with microbes isolated from weathered stones are required in order to understand the biological mechanisms involved in stone deterioration . We have described, as commented in the text, how fungal colonization observed on scaglia may be the result of the fine grain size of rock, whereas inhibition of growth on marble may depend on the surface characteristics of calcite grains after grinding . The extent of microbial growth clearly depends on the quantity of cations released in solution . However, fungal growth may, in turn, induce a decrease in pH, thus promoting mineral chemical attack . These observation points to selective action of fungal species in promoting weathering well evidenced by the presence of different extents of cations released in suspension from the same sample . Detailed studies are in progress in order to go into this question. Water Sci Technol, 2003, 48(9), 103 - 11 Low temperature biodegradation of airport de-icing fluids; Revitt DM et al.; The biodegradabilities of glycol- and acetate-based aircraft de-icing fluids on airport surfaces have been investigated at three temperatures between 0 degrees C and 10 degrees C . The aqueous solubilities of these substances can result in high BOD loadings in runoff and pose serious toxicity problems in receiving waters . The measured surface biodegradation rates for de-icing products based on ethylene/diethylene glycol (Konsin), propylene glycol (Kilfrost) and potassium acetate (Clearway) at 4 degrees C were 0.082, 0.073 and 0.033 day(-1) . The resulting reductions in the potential BOD loadings, of a single application of a typical mixture of these products, over a 5 day biodegradation period are predicted to be 32.9%, 30.2% and 21.4%, respectively at 8 degrees C, 4 degrees C and 1 degrees C . For consecutive daily applications, the comparable cumulative reductions over 5 days are 20.8%, 18.9% and 13.3% . The subsequent savings in the amount of treatment required for airport runoff prior to safe discharge to receiving waters are discussed and hence the relevance of surface biodegradation processes to the design of stormwater treatment systems involving the wash-off of biodegradable pollutants following retention on urban surfaces. J Dent Res, 2004 Jan, 83(1), 22 - 6 Salivary esterase activity and its association with the biodegradation of dental composites; Finer Y et al.; Pseudocholinesterase (PCE) and cholesterol esterase (CE) can hydrolyze bisphenylglycidyl dimethacrylate (bisGMA) and triethylene glycol dimethacrylate (TEGDMA) monomers . This study will test the hypothesis that enzyme activities showing CE and PCE character are found in human saliva at levels sufficient to hydrolyze ester-containing composites important to restorative denstistry . The study also seeks to ask if the active sites of CE and PCE with respect to composite could be inhibited . Photo-polymerized model composite resin was incubated in PCE and CE solutions, in the presence and absence of a specific esterase inhibitor, phenylmethylsulfonyl fluoride (PMSF) . Incubation solutions were analyzed for resin degradation products by high-performance liquid chromatography (HPLC), UV spectroscopy, and mass spectrometry . Saliva was found to contain both hydrolase activities at levels that could degrade composite resins . PMSF inhibited the composite degradation, indicating a material hydrolysis mechanism similar to the enzymes' common function. Environ Sci Pollut Res Int, 2003, 10(6), 379 - 84 Practical applications of the Fenton reaction to the removal of chlorinated aromatic pollutants . Oxidative degradation of 2,4-dichlorophenol; Detomaso A et al.; BACKGROUND: Chlorophenols (CPs) constitute a group of organic pollutants that are introduced into the environment as a result of several man-made activities, such as uncontrolled use of pesticides and herbicides, and as byproducts in the paper pulp bleaching . Promising removal technologies of chlorinated aromatics consist in the application of advanced oxidation processes (AOPs) that can provide an almost total degradation of a variety of contaminants . Among these, wide application find Fenton systems based on generation of reactive species having a high oxidizing power, such as hydroxyl radical HO* . Our objective was that of determining the overall degradation efficiency of the model compound 2,4-dichlorophenol (DCP) by thermal Fenton-type oxidation systems with a view toward defining in more details relevant process parameters, the effect of reaction temperature and of co-catalyst Cu2+ . METHODS: Reaction conditions were similar to those generally adopted as optimal in many practical applications, i.e . pollutant/Fe2+ (as FeSO4) ratio ca . 20, Fe2+/Cu2+ (co-catalyst) 2:1, pH adjusted and controlled at pH 3, and H2O2 in excess (up to four-fold over the stoichiometric amount required for complete mineralization) . RESULTS AND DISCUSSION: The results demonstrate that it is advantageous to carry out the reaction at a temperature markedly higher (70 degrees C) than ambient . The stepwise addition of H2O2 in aliquots yields an efficient transformation, while allowing a convenient control of the reaction exothermicity . Under these conditions, the essentially complete removal of the initial DCP is accomplished using just one equiv of H2O2 during 15 min; excess H2O2 (5 equivalents) yields extensive substrate mineralization . Also relevant, at 70 degrees C dechlorination of the initial DCP (and of derived reaction intermediates) is remarkably extensive (3-5% residual TOX), already with the addition of 1 equiv of H2O2 . At the end of the reaction, IC and IC-MS analyses of the solution reveal that only low-molecular weight carboxylic acid (acetic, formic, oxalic, malonic, tartaric, etc.) contribute to the residual TOC . CONCLUSIONS: The whole of the results herein point to the advantage of performing the process at temperatures substantially higher than ambient (70 degrees C) . Under the conditions adopted, almost complete degradation of the initial toxic compound can be achieved using hydrogen peroxide in fair excess (e.g., 3.5 equiv H2O2) . RECOMMENDATIONS AND OUTLOOK: In applying practical Fenton-type degradation systems to heavily polluted wastes, either for the pre-treatment of waters with a high COD value prior to biodegradation or for complete mineralization of pollutants, the set up of appropriate reaction conditions appears to be a key factor . Also, it is desirable to keep the concentration of iron salts within the lower limits in order to minimize the production and disposal of iron oxide sludges. Water Sci Technol, 2003, 48(8), 177 - 83 Biodegradation of polycyclic aromatic hydrocarbons (PAHs) by microbial consortia enriched from mangrove sediments; Tam NF et al.; Surface sediments from two mangrove swamps in Hong Kong were enriched to obtain PAH-degrading microbial consortia . The consortium from sediments enriched with phenanthrene (Phe) in Ma Wan, a mangrove swamp next to a boat anchorage, was effective in degrading PAH with 96.7% and 89.9% Phe degradation at 0 and 10 ppt salinities, respectively . The Phe-enriched microbial consortium could also use pyrene (Pyr) as the sole carbon source but the degradation was much less (around 15%) . On the other hand, the Phe-enriched consortium from sediments in Yi O, a mangrove swamp recently polluted by an oil spill, completely removed Phe and Pyr at both 0 and 10 ppt salinities . This suggests that different consortia were selected in two sediments using the same PAH substrate . Not only sediments, PAH substrate used for enrichment also selected different consortia . The Pyr- and Fla-enriched Yi O consortia only achieved 10.5 and 4.5% Phe degradation, respectively and the corresponding pyrene degradation was 7 and 40% . Among the three PAH compounds, fluoranthene (Fla) was most difficult to degrade, and 21.1, 11.3, and 36.8% Fla were degraded by Phe-, Fla- and Pyr-enriched cultures, respectively. Arh Hig Rada Toksikol, 2003 Sep, 54(3), 189 - 95 Comparison of diethylene glycol and phenol biodegradability by different test methods; Zgajnar Gotvajn A et al.; Biodegradation is generally recognised as an important removal mechanism for pollutants in natural ecosystems . It determines the concentration of substances in the environment . According to the legislation of the European Union, there are three levels for biodegradability testing protocols for chemicals which cover different test conditions . This paper describes one such multilevel approach to biodegradation testing . Four different tests were performed on diethylene glycol and phenol . Diethylene glycol did not fulfill the requirements for ready biodegradable substances, while it degraded well in wastewater treatment plant simulation test . Phenol in turn, resulted ready biodegradable, and its biodegradability depended less on experimental conditions than the biodegradability of diethylene glycol . This corroborates the importance of combining different test methods to obtain relevant biodegradability data. Water Res, 2004 Jan, 38(2), 375 - 84 4-nitrophenol biodegradation in a sequencing batch reactor: kinetic study and effect of filling time; Tomei MC et al.; Biodegradation kinetics of 4-nitrophenol (4NP) was investigated in a lab-scale sequencing batch reactor fed with the compound as the sole carbon source . The experimental results showed that complete 4NP removal can be easily achieved with acclimatized biomass, even if an inhibition kinetics is observed; furthermore, an improvement in the removal kinetics is obtained if the substrate concentration peak, reached in the reactor at the end of the filling time, is maintained to quite a low value . Both long feed phase and high biomass concentration are effective in reducing the substrate concentration peak and then improving the process efficiency . Kinetic test data are well correlated by the Haldane equation, with a saturation constant Ks and an inhibition constant KI, of 17.6 and 30.7 (mg l(-1) 4NP), respectively, whereas the maximum removal rate was in the range of 3.3-8.4 (mg 4NP mg VSS(-1) d(-1)) depending on the substrate concentration peak reached in the reaction phase. J Environ Qual, 2003 Nov-Dec, 32(6), 2207 - 15 Modeling of sorption and biodegradation of parathion and its metabolite paraoxon in soil; Saffih-Hdadi K et al.; To investigate the distribution of parathion {O,O-diethyl O-(4-nitrophenyl) phosphorothioate} and its highly toxic metabolite paraoxon {O,O-diethyl O-(4-nitrophenyl)phosphate} between the soluble and sorbed pools in the soil, batch experiments were conducted to evaluate the rate of adsorption and desorption of 14C-labeled parathion and paraoxon in soil . The mineralization and degradation of these products were also investigated during a 56-d experiment under controlled laboratory conditions . Adsorption patterns indicated initial fast adsorption reactions occurring within 4 h for both parathion and paraoxon . We also observed the formation of nonextractable residues . The paraoxon was more intensively degraded than the parathion, and production of p-nitrophenol and other metabolites was observed . A kinetic model was developed to describe the sorption and biodegradation rates of parathion, taking into account the production, retention, and biodegradation of paraoxon, the main metabolite of parathion . After fitting the parameters of the model we made a simulation of the kinetics of the appearance and disappearance of paraoxon . From the simulation we predicted a quantity of metabolite in the liquid phase amounting to 1% of the quantity of parathion initially applied . This is in agreement with the experimental data. J Environ Sci Health A Tox Hazard Subst Environ Eng, 2003, 38(12), 2857 - 65 Variation of microcystins in a lake for water supply; Zhang WH et al.; A site investigation was conducted to correlate the relationships between microcystins (MC) concentration and algal growth in Dianchi Lake in China . Laboratory experiments were undertaken to test the effects of sediment adsorption, photoirradiation and biodegradation on microcystins removal . Bioaccumulation of microcystins was also determined using silver carp fish . It was observed that MC concentrations varied in accordance with algae growth in Dianchi Lake . The results obtained in the laboratory demonstrated that the removal of MC with fresh sediments was less than 10%, photoirradiation removed more than 75% MC within two hours, and the biodegradation needed much longer time to produce substantial degradation of MC . The results suggest that bioaccumulation of microcystins in fish was not significant in Dianchi Lake. Cancer Lett, 2004 Jan 8, 203(1), 59 - 69 Cytostatic and cytotoxic activity of synthetic genistein glycosides against human cancer cell lines; Polkowski K et al.; Genistein, the principal soy isoflavone, is a molecule of great interest as an innovative chemotherapeutic agent or as a lead-compound in anticancer drug design . To enhance intrinsic activity of genistein and to explore its pharmacophoric potential, its glycosidic derivatives were synthesized . On the basis of structural features and calculated lipophilicity coefficient (ClogP) the derivatives were classified as hydrophilic (i.e . those containing free sugar moiety) or lipophilic (i.e . those with alkylated or acylated sugar hydroxyls) . The in vitro cytostatic and cytotoxic studies showed hydrophilic glycosides to be practically inactive against human cancer cell lines when compared to the free aglycone . On the contrary, lipophilic glycosides were significantly more active than the parent isoflavone although the correlation between ClogP and the activity was not clear . On the basis of GI50 and LC50 values two of the most active glycosides were found to be several times more potent in their cytostatic and cytotoxic effect than genistein . Additionally all lipophilic glycosides were revealed to exhibit different mode of action in comparison to genistein . It may suggest that these compounds do not undergo rapid biodegradation, either in culture media or inside cells, and exert their biological effects primarily as intact molecules. Biodegradation, 2003 Dec, 14(6), 373 - 84 Effects of heterogeneity and experimental scale on the biodegradation of diesel; Davis C et al.; Biodegradation of petroleum hydrocarbon contamination is a common method for remediating soils and groundwater . Due to complexities with field-scale studies, biodegradation rates are typically evaluated at the bench-scale in laboratory studies . However, important field conditions can be difficult to mimic in the laboratory . This study investigates three scaling factors that can impact laboratory biodegradation rates and that are frequently unaccounted for in typical laboratory experimental procedures . These factors are soil heterogeneity, morphology of petroleum hydrocarbon non-aqueous phase liquids (NAPLs) and soil moisture distribution . The effects of these factors on the biodegradation rate of diesel NAPL is tested under a variety of experimental procedures from well-mixed batch studies to four-foot static soil columns . The results indicate that a high degree of variability results from even small-scale heterogeneities . In addition, it appears that as the experimental scale increases, the measured biodegradation rates slow . The results indicate that diesel biodegradation rates derived from small-scale experiments are not necessarily representative of field-scale