Several strains of silkworm Bombyx mori were tested for the gene delivery feasibility of Autographa californica nucleopolyhedrovirus (AcNPV) in vivo. In contrast to the general belief that silkworms were non-permissive to AcNPV, we found that 3 of 7 tested strains were AcNPV permissive. To dispel the physiological influence of the ecdysteroid UDP-glucosyltransferase (EGT) on the silkworm, we modified the AcNPV bacmid by disruption of that gene. Expression pattern of EGFP in tissues of silkworm larvae after injection of EGT-null AcNPV vector carrying EGFP cassette was revealed by green fluorescence and Western blot analysis. Viral DNA was detected and semi-quantified in various kinds of tissues by dot blot assay. Active recombinant virus from larval hemolymph was detectable by TCID(50). Our results indicate that some strains of silkworm were permissive to AcNPV, which could serve as a novel gene deliver tool to silkworm in vivo.

This study examined a novel reuse of alum sludge, an inescapable by-product of drinking water treatment process when aluminium salt is added as a coagulant, as the main medium in a laboratory-scale multi-stage constructed wetland (CW) system for reject water treatment. Such reject water is a main concern in municipal wastewater treatment plant (MWWTP) for increasing the organic and nutrient loading. A ‘tidal flow’ strategy was employed to enhance the wetland aeration to stimulate organic matters (OM) and ammoniacal-nitrogen (N) oxidation while the ‘step feed’ operation was adopted to supply the necessary amount of carbon source for denitrification. The results reveal that alum sludge acting as P adsorbent can secure the P removal. Meanwhile, high removals of N and OM can also be obtained due to the active bacteria growth on the alum sludge surface. The results show that average removal efficiencies of 65.4 ± 12.3% for chemical oxygen demand (COD), 67.8 ± 9.2% for five-day biochemical oxygen demand (BOD5), 33.6 ± 17.0% for N and 99.5 ± 0.49% for P can be achieved over a period of 190 days. This indicates that novel reuse of alum sludge as medium in CW system can provide a promising approach for reject water treatment. Therefore, it will significantly reduce the amount of pollutant feedback through reject water recycling in a MWWTP.