Structural characterization and induction of tumor cell apoptosis of polysaccharide from purple sweet potato (Ipomoea batatas (L.) Lam).

The carbohydrate is the main ingredient of purple sweet potato. A polysaccharide, named PSP, was separated and purified from purple sweet potato by extraction with hot water, precipitation with ethanol, deproteinization with Sevag reagent and column chromatography with Sephadex G-100. The purity and structure were studied with HPLC, UV-Vis, GC-MS and NMR. The PSP is a neutral polysaccharide with Mw of 470 kDa. The monosaccharide composition of PSP contained D-xylose, d-glucose, D-galactose with ratio of 1.0: 8.3: 1.3. The backbone of PSP was composed of the residues of →6)-D-Glcp-(1 â†’ and →2, 6)-D-Glcp-(1→. The branches of PSP contained the residues of →3)-D-Galp-(1→, and D-Xylp-(1→. The antitumor activity in vitro of PSP was analyzed with HT-29 cells. And the SEM, AO staining, MDC staining and hoechst 33342 staining were performed to study the effect on apoptosis of HT-29 cells by PSP. The results revealed that the PSP can significantly inhibit the proliferation of HT-29 cells from induction apoptosis. The manuscript provided valuable knowledges on structural characteristics of the polysaccharides from purple sweet potato.

A polysaccharide from Pleurotus citrinopileatus mycelia enhances the immune response in cyclophosphamide-induced immunosuppressed mice via p62/Keap1/Nrf2 signal transduction pathway.

The manuscript aimed to study the immunoregulatory activity and the mechanism of the polysaccharide (CMP) from Pleurotus citrinopileatus mycelia. The mice were divided into normal group, model group, different dosage of CMP (50, 100 and 200 mg/kg, respectively) groups and levamisole hydrochloride treated group. The results showed that, compared with the model group, CMP could significantly improve the auricle swelling rate, half hemolysis value and phagocytic index in mice. The indices of immune organs were raised, and tissue damage of spleen was relieved. Splenic Th1 cells were decreased, while Th2 cells were increased, furthermore the proliferation of splenic lymphocytes and the cytotoxicity of NK cells were increased. The levels of interleukin-12 (IL-12), interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) in spleen were decreased, while interleukin-4 (IL-4) and interleukin-10 (IL-10) were increased. In serum and spleen, the levels of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities were increased, while the level of malondialdehyde (MDA) was decreased. And the levels of Immunoglobulin were also increased. Western blot showed that CMP had immunoregulatory activity by activating Nrf2, Keap1, p62, HO-1, and NQO1 in the p62/Keap1/Nrf2 signaling pathway. The study proved that CMP could be used as a biological Immune regulating agent.

Negative Differential Friction Predicted in 2D Ferroelectric In2 Se3 Commensurate Contacts.

At the macroscopic scale, the friction force (f) is found to increase with the normal load (N), according to the classic law of Da Vinci-Amontons, namely, f = µN, with a positive definite friction coefficient (µ). Here, first-principles calculations are employed to predict that, the static force f, measured by the corrugation in the sliding potential energy barrier, is lowered upon increasing the normal load applied on one layer of the recently discovered ferroelectric In2 Se3 over another commensurate layer of In2 Se3 . That is, a negative differential friction coefficient µ can be realized, which thus simultaneously breaking the classic Da Vinci-Amontons law. Such a striking and counterintuitive observation can be rationalized by the delicate interplay of the interfacial van der Waals repulsive interactions and the electrostatic energy reduction due to the enhancement of the intralayer SeIn ionic bonding via charge redistribution under load. The present findings are expected to play an instrumental role in design of high-performance solid lubricants and mechanical-electronic nanodevices.