[Effect of Polysilicic Acid on the Deposition Behavior of Different Aluminum Species].

To understand the water quality problems caused by deposition and re-dissolution behaviors of residual aluminum in drinking water distribution system (DWDS), the effect of polysilicic acid on the deposition and re-dissolution behaviors of different aluminum species was investigated by using jar tests and quartz crystal microbalance, which could demonstrate the deposition behavior of different aluminum species and the physic-chemical properties of deposited layers. The results showed that the effect of polysilicic acid on the deposition behavior of different aluminum species was significant. Al0 (mainly monomeric species), Al13 and Al30 (polymeric species) could react rapidly with polysilicic acid, and some insoluble products formed. However, the stability of insoluble products from different aluminum species was distinct. The insoluble product formed by reaction of Al0 with polysilicic was relatively stable. With regard to the systems of polysilicic acid with Al13 and Al30, the dissolved aluminum concentration increased with reaction time, which indicated that the deposited product could be gradually transformed to soluble monomeric or oligomeric aluminum species. Compared with the influence of Al/Si ratio on Al0, the ratio of aluminum to silicon significantly affected the deposition and re-dissolution behavior of Al13 and Al30, and the re-dissolution rate of insoluble aluminum was the most rapid when the ratio of aluminum with silica was 0.2:20 (as mass ratio of Al to SiO2).

Oral vaccination with the porcine rotavirus VP4 outer capsid protein expressed by Lactococcus lactis induces specific antibody production.

The objective of this study to design a delivery system resistant to the gastrointestinal environment for oral vaccine against porcine rotavirus. Lactococcus lactis NZ9000 was transformed with segments of vP4 of the porcine rotavirus inserted into the pNZ8112 surface-expression vector, and a recombinant L. lactis expressing VP4 protein was constructed. An approximately 27 kDa VP4 protein was confirmed by SDS-PAGE , Western blot and immunostaining analysis. BALB/c mice were immunized orally with VP4-expression recombinant L. lactis and cellular, mucosal and systemic humoral immune responses were examined. Specific anti-VP4 secretory IgA and IgG were found in feces, ophthalmic and vaginal washes and in serum. The induced antibodies demonstrated neutralizing effects on porcine rotavirus infection on MA104 cells. Our findings suggest that oral immunization with VP4-expressing L. lactis induced both specific local and systemic humoral and cellular immune responses in mice.