Feasibility study of a pilot-scale sewage treatment system combining an up-flow anaerobic sludge blanket (UASB) and an aerated fixed bed (AFB) reactor at ambient temperature

A feasibility test of a 17 m3-pilot-scale sewage treatment system was carried out by continuous feeding of raw municipal sewage under ambient temperature conditions. The system consisted of a UASB and an aerated fixed bed reactor. Some of the effluent from the fixed bed reactor was returned to the UASB influent in order to provide a sulfate source. The total BOD of 148-162 mg l(-1) in the influent was reduced to a more desirable 11-25 mg l(-1) in the final effluent. The levels of methane-producing activity from acetate and H2/CO2 gas at 10 degrees C were only 2% and 0% of those at 35 degrees C, respectively. On the other hand, the sulfate-reducing activity levels of the UASB sludge were relatively high at 10 degrees C, for example, 18% for acetate and 9% for H2/CO2 gas, compared to the activity levels at 35 degrees C. Therefore, BOD oxidization by sulfate reduction in the UASB was greater than that by methane production under low temperature conditions. This sulfate-reducing activity tended to be proportional to the copy number of adenosine-5'-phosphosulfate (APS) reductase genes in DNA extracted from the sludge.     

Production of hydrogen and methane from organic solid wastes by phase-separation of anaerobic process

Phase-separated two-stage anaerobic process was examined and evaluated using artificial organic solid waste in laboratory scale. Acidogenic process, which was combined with subsequent methanogenic process using packed-bed reactor, was operated emphasizing on either hydrogen production, or solublizing efficiency of solid materials. In either effluent from hydrogenogenic, or solublizing operation, maximum allowable OLR achieved at methanogenesis was higher than the single methanogenic process. Hydrogenogenic operation was more suitable to combine methanogenic process than solublizing operation, since retention time of hydrogenogenic operation was much shorter than the solublizing operation, obtaining almost the same levels of overall removal efficiency in both COD and VSS. The combination of hydrogenogenic operation in acidogenic process and methanogenic process produced approximately 442mmoll-reactor(1)days(-1) of methane and 199mmoll-reactor(1)days(-1) of hydrogen at 25h of total retention time indicating 82% of COD removal with 96% of VSS decomposition.     

Antibiotic effect of amoxicillin on the feces composting process and reactivation of bacteria by intermittent feeding of feces

The aim of this work was to investigate the single exposure effect of amoxicillin on the feces composting process and the possibility of its bacterial reactivation by intermittent feeding of feces. The respiratory activity of the bacteria during the process after receiving exposure to several dosages of amoxicillin indicated a decrement of treatment performance, which was caused by the reduction of the initial viable bacterial count and activity brought about by the amoxicillin dosage. The amount of remaining feces was proportional to the initial concentration of amoxicillin, and even though no amoxicillin was detected, no automatic reactivation was observed, either. An intermittent feces feeding test was conducted to reactivate the bacteria. For the 10 and 100microg-amoxicillin/g dry systems, reactivation was observed, but for the 1000microg/g dry, no reactivation was seen. Finally, an intermittent feces feeding test was conducted with sterilized sawdust and the result indicated that the feces acted as a substrate rather than as a bacterial carrier.     

Synthesis of fluorescent-labeled aeruginosin derivatives for high-throughput fluorescence correlation spectroscopy assays

The design and solid-phase synthesis of effective fluorescent-labeled aeruginosin derivatives and their application to the fluorescence correlation spectroscopy (FCS)-based competitive binding assay of an aeruginosin library are described. The phenolic hydroxyl group on the (R)-3-(4-hydroxyphenyl)lactic acid (d-Hpla) residue was observed to be suitable for connecting Rhodamine green derivative with minimum loss of biological activity. In addition, the FCS-based binding assay of the library using fluorescent-labeled chemical probes was also achieved.     

Ultrasound enhances retrovirus-mediated gene transfer

Viral vector systems are efficient for transfection of foreign genes into many tissues. Especially, retrovirus based vectors integrate the transgene into the genome of the target cells, which can sustain long term expression. However, it has been demonstrated that the transduction efficiency using retrovirus is relatively lower than those of other viruses. Ultrasound was recently reported to increase gene expression using plasmid DNA, with or without, a delivery vehicle. However, there are no reports, which show an ultrasound effect to retrovirus-mediated gene transfer efficiency. Retrovirus-mediated gene transfer systems were used for transfection of 293T cells, bovine aortic endothelial cells (BAECs), rat aortic smooth muscle cells (RASMCs), and rat skeletal muscle myoblasts (L6 cells) with beta-galactosidase (beta-Gal) genes. Transduction efficiency and cell viability assay were performed on 293T cells that were exposed to varying durations (5 to 30 seconds) and power levels (1.0 watts/cm(2) to 4.0 watts/cm(2)) of ultrasound after being transduced by a retrovirus. Effects of ultrasound to the retrovirus itself was evaluated by transduction efficiency of 293T cells. After exposure to varying power levels of ultrasound to a retrovirus for 5 seconds, 293T cells were transduced by a retrovirus, and transduction efficiency was evaluated. Below 1.0 watts/cm(2) and 5 seconds exposure, ultrasound showed increased transduction efficiency and no cytotoxicity to 293T cells transduced by a retrovirus. Also, ultrasound showed no toxicity to the virus itself at the same condition. Exposure of 5 seconds at the power of 1.0 watts/cm(2) of an ultrasound resulted in significant increases in retrovirus-mediated gene expression in all four cell types tested in this experiment. Transduction efficiencies by ultrasound were enhanced 6.6-fold, 4.8-fold, 2.3-fold, and 3.2-fold in 293T cells, BAECs, RASMCs, and L6 cells, respectively. Furthermore, beta-Gal activities were also increased by the retrovirus with ultrasound exposure in these cells. Adjunctive ultrasound exposure was associated with enhanced retrovirus-mediated transgene expression in vitro. Ultrasound associated local gene therapy has potential for not only plasmid-DNA-, but also retrovirus-mediated gene transfer.     

The human airway trypsin-like protease modulates the urokinase receptor (uPAR, CD87) structure and functions

The human airway trypsin-like protease (HAT) is a respiratory epithelium-associated, type II transmembrane serine protease, which is also detected as an extracellular enzyme in lung fluids during airway inflammatory disorders. We have evaluated its capacity to affect the urokinase-type plasminogen activator receptor (uPAR), a membrane glycolipid-anchored, three-domain (D1D2D3) glycoprotein that plays a crucial role in innate immunity and inflammation by supporting cell migration and matrix degradation, with structure and biological properties that can be regulated via limited endoproteolysis. With the use of immunoblotting, flow immunocytometry, and ELISA analyses applied to a recombinant uPAR protein and to uPAR-expressing monocytic and human bronchial epithelial cells, it was shown that exposure of uPAR to soluble HAT in the range of 10-500 nM resulted in the proteolytic processing of the full-length (D1D2D3) into the truncated (D2D3) species, with cleavage occurring in the D1 to D2 linker sequence after arginine residues at position 83 and 89. Using immunohistochemistry, we found that both HAT and uPAR were expressed in the human bronchial epithelium. Moreover, transient cotransfection in epithelial cells showed that membrane coexpression of the two partners produced a constitutive and extensive shedding of the D1 domain, occurring for membrane-associated HAT concentrations in the nanomolar range. Because the truncated receptor was found to be unable to bind two of the major uPAR ligands, the adhesive matrix protein vitronectin and the serine protease urokinase, it thus appears that proteolytic regulation of uPAR by HAT is likely to modulate cell adherence and motility, as well as tissue remodeling during the inflammatory response in the airways.