31: Upregulation of IL-21 gene expression by HHV-6: contribution of CD4+ T cells to host's anti-viral innate immune response

Abstract

Ultrasonication was applied to modify the structural and physicochemical properties of the (1 → 3)(1 → 6)-α-d-glucans from Leuconostoc citreum SK24.002. Upon ultrasound treatment, both the UV absorption at 220 nm and number-average molecular weight decreased substantially in the first 20 min, and then incrementally decreased to a plateau value after 160 min. The molecular weight distribution curves gradually shifted to the low molecular weight region with a narrower distribution and the chain degradation reaction followed the random scission model. NMR results showed that the partial consecutive α-1,6 linkages in the limited regions were ruptured by acoustic cavitations. The viscosity of modified glucan solution dropped remarkably and the glucan after ultrasonication for more than 20 min was dissolved in water to give solutions of 30 g/100 ml or greater. The Newtonian plateaus for sonicated glucan solutions were observed at the high shear rates (1–100 1/s).