A coupled UV photolysis-biodegradation process for the treatment of decabrominated diphenyl ethers in an aerobic novel bioslurry reactor.

The commercial flame retardant is an emerging contaminant (EC) commonly found in soils and sediments. A coupled UV-photolysis-biodegradation process was used to decompose decabromodiphenyl ether (BDE-209) in clay slurries. A novel bioslurry bioreactor (NBB) was employed in which BDE-209 degradation was maximized by the simultaneous application of LED UVA irradiation and biodegradation by a mixed bacterial culture. The rate of BDE-209 degradation decreased in the order: coupled UV photolysis-biodegradation (1.31 × 10-2 day-1) > UV photolysis alone (1.10 × 10-2 day-1) > biodegradation alone (1.00 × 10-2 day-1). Degradation intermediates detected included hydroxylated polybrominated diphenylethers, partially debrominated PBDE congeners and polybrominated dibenzofuran. The UV-resistant bacterial strains isolated that could utilize BDE-209 as a sole carbon source included Stenotrophomonas sp., Pseudomonas sp., and Microbacterium sp. These strains encoded important functional genes such as dioxygenase and reductive dehalogenases. Continuous UV irradiation during the NBB process affected various biochemical oxidative reactions during PBDEs biodegradation. Simultaneous photolysis and biodegradation in the NBB system described reduces operational time, energy, expense, and maintenance-demands required for the remediation of BDE-209 when compared to sequential UV-biodegradation process or to biodegradation alone.

The temporal and spatial variations of acid aerosols in the geothermal area of metropolitan Taipei, Taiwan.

This study involved sampling over 1 year of data on exposure to acid aerosols in the geothermal area of metropolitan Taipei. The temporal and spatial variations of the concentrations of acid aerosols were assessed by sampling at three sites: A, B, and C. Results indicate that the SO2 concentrations lead the concentrations of other acid aerosols at site C because two active fumaroles surround this site. The mean SO2 concentrations at sites A, B, and C were 2.4, 2.4, and 6.2 ppb. Previous studies have found that H2S levels were highest at site C. However, the SO4(-2) and H+ concentrations among the three sites were similar. The mean aerosol SO4(-2) concentrations were 7.0, 5.7, and 5.7 microg m(-3) at sites A, B, and C, respectively; their H+ concentrations were 5.5, 4.2, and 5.4 nmol m(-3). No seasonal variations are observed for most of the acid aerosols in the geothermal area except that the types of hot spring affect the SO4(-2) concentration nearby. The different seasonal fluctuation among the sites reflect the determinant of SO4(-2) emission from different geothermal sources. Sulfur-rich aerosols and some SO2 emitted from geothermal sources are obvious. The predominance of nitrogen-containing gases (sum of NO2 + HNO2 + HNO3) over SO2 indicates the importance of the anthropogenic origin of emissions. The effect of multiple exposures to sulfur-rich aerosol (including H2S, SO2, and SO4(-2)), H+, and nitrogen-containing aerosols on the health of nearby residents warrants concern.

Differential effects of prenyl pyrophosphates on the phosphatase activity of phosphotyrosyl protein phosphatase.

Phosphotyrosyl protein phosphatase (PTPase) 1B was purified from human placenta. Immunoprecipitation analysis revealed that the isolated PTPase 1B appears as a complex with the receptor for protein kinase C (RACK1) and protein kinase C (PKC)delta. The abilities of PTPase 1B and PKCdelta to associate with RACK1 were reconfirmed by an in vitro reconstitution experiment. The E. coli expressed and biotinylated mice-RACK1-encoded fusion protein was capable of recruiting PTPase 1B and PKCdelta in the antibiotin immunoprecipitate as a complex of PTPase 1B/RACK1/PKCdelta. Thus PTPase 1B enzyme preparation was subjected to further purification by selective binding of PTPase 1B onto PEP(Taxol) affinity column in the absence of ATP. The purified PTPase 1B enzyme exihibited dose-dependent phosphatase activity towards [gamma-(32)P]-ATP labeled mice beta-tubulin-encoded fusion protein. The dephosphorylation reaction with PTPase 1B was enhanced with geranylgeranyl pyrophosphate, but not with farnesyl pyrophosphate. Interestingly, additional incubation of the purified PTPase 1B enzyme preparation with RACK1, geranylgeranyl pyrophosphate failed to modulate the dephosphorylation activity of PTPase 1B. In contrast, the enhancement effect of farnesyl pyrophosphate on the kinase activity of PKCdelta was sustained in the presence of RACK1. That is, farnesyl pyrophosphate may function as a signal to induce the kinase activity of PKCdelta in PTPase 1B/RACK1/PKCdelta complex but geranylgeranyl pyrophosphate may not for PTPase 1B. J. Exp. Zool. 301A:307-316, 2004.