Novel Bacteria-Immobilized Cellulose Acetate/Poly(ethylene oxide) Nanofibrous Membrane for Wastewater Treatment.

In this study, electrospun cellulose acetate - poly(ethylene oxide) nanofibrous membrane was found to be unique in immobilizing bacterial cells. Here, removal of methylene blue in aqueous media was achieved by using isolated species of bacteria (Bacillus paramycoides) from industrial wastewater and immobilized on cellulose acetate- poly(ethylene oxide) nanofibers using DMSO as a solvent. The decolorization time was varied from 0 to 72 h, different dye concentrations from 20 to 200 mg/L and bacterial cells count was investigated to achieve the maximum MB removal by bacteria-immobilized CA/PEO nanofibrous membrane. The effective dye decolorization was achieved within 48 h and MB removal % was around 93%. Furthermore, reusability of the bacteria-immobilized CA/PEO nanofibrous membrane was tested. It was found that after the 4th usage, 44% of the dye decolorization capacity still could be achieved. These results are promising and suggest that bacteria-immobilized CA/PEO nanofibrous membrane could be economically feasible and eco-friendly when used in MB removal from industrial wastewater. Combination of both adsorption and biodegradation methods was found to be effective in MB removal from aqueous media.

Effects of ivermectin on blood-feeding Phlebotomus papatasi, and the promastigote stage of Leishmania major.

Ivermectin (IVM) is a chemically modified macrocyclic lactone of Streptomyces avermitilis that acts as a potent neurotoxin against many nematodes and arthropods. Little is known of IVM's effect against either blood-feeding Phlebotomus sand flies, or the infective promastigote stage of Leishmania transmitted by these flies. We injected hamsters subcutaneously with two standard IVM treatments (200 and 400 µg/kg body weight) and allowed cohorts of Leishmania major-infected Phlebotomus papatasi to blood-feed on these animals at various posttreatment time points (4 h, 1, 2, 6, and 10 days). Infected and uninfected sand flies that bit treated and untreated hamsters served as controls. Serum levels of IVM in low- and high-dose-treated hamsters were determined at the five time points. Sand fly mortality following blood feeding was recorded at 24-h intervals and, in relation to IVM treatment, was time and dose dependent. Mortality was most rapid and greatest among infected flies that fed nearest to time of dosing. Mean survival of infected sand flies after feeding on untreated hamsters was 11.5 days, whereas that of infected sand flies that fed 4 h, 1 day, or 2 days posttreatment on high-dose-treated hamsters (400 µg/kg) was 1.6, 2.1, and 2.7 days, respectively. Infected and uninfected sand flies that blood fed 6 days following low-dose IVM treatment (200 µg/kg) still experienced significantly greater mortality (p < 0.02) than controls. Promastigotes dissected out of surviving flies that fed on IVM-treated hamsters showed typical motility and survival. Moreover, 21.7% of IVM-treated hamsters developed lesions after being fed upon by infected sand flies. L. major promastigotes appeared to be tolerant to ng/mL blood levels of IVM that caused significant mortality for up to 10 days posttreatment in blood-feeding P. papatasi.