A phosphamide nucleotide analog: a substrate for polymerase synthesis of DNA.

A type of modified nucleotide, deoxynucleotide γ-amidotriphosphates (dNTPγNH2s), exhibited around five times higher stability than dNTPs. These phosphamide nucleotides can be utilized by several DNA polymerases, and the amplification of a 10 kb DNA fragment through the polymerase chain reaction (PCR) can be accomplished even under conditions of high temperature, extended storage, or repeated freeze-thaw cycles. However, the control PCR with standard dNTPs was unsuccessful. These results indicate that dNTPγNH2s have the potential to substitute dNTPs in PCR.

Structure and physicochemical properties of polysaccharides from Poria cocos extracted by deep eutectic solvent.

Poria cocos, a famous traditional Chinese medicine and a well-known food or food supplement, has shown therapeutic potential against cancer and the uneasiness of the mind. In addition, polysaccharides (PCPs) in this fungus were found to be various bioactive. In this work, one such PCP, PCP-1, extracted by deep eutectic solvent (DES) and separated using Sephadex G-15 columns, was characterized using GC-MS, HPGPC, FT-IR, and NMR, while also tested for physicochemical properties. Results indicated that PCP-1 contained 96.89 ± 3.21% total sugars and was a glucan with molecular weight of 3.2 kD. The main glycosidic linkage was 1,3-linked Glcp with 96.82 mol% content and a triple helix structure, and ß-D-Glcp-(1 → linkage connected to the main chain through an O-6 atom was the backbone structure. In terms of the physicochemical property, PCP-1 was soluble in water, but not in organic solvent, and processed a relative high water-holding capacity (8.64 ± 0.14 g/g) and low oil-holding capacity (2.52 ± 0.21 g/g). In addition, in vitro, PCP-1 was found to have the ability of scavenging DPPH, hydroxyl free radical, superoxide anion radical and reducing ferric at different levels. This research would be useful for the further application of PCP-1.

Antioxidant capacities of the selenium nanoparticles stabilized by chitosan.

BACKGROUNDS: Selenium (Se) as one of the essential trace elements for human plays an important role in the oxidation reduction system. But the high toxicity of Se limits its application. In this case, the element Se with zero oxidation state (Se0) has captured our attention because of its low toxicity and excellent bioavailability. However, Se0 is very unstable and easily changes into the inactive form. By now many efforts have been done to protect its stability. And this work was conducted to explore the antioxidant capacities of the stable Se0 nanoparticles (SeNPs) stabilized using chitosan (CS) with different molecular weights (Mws) (CS-SeNPs). RESULTS: The different Mws CS-SeNPs could form uniform sphere particles with a size of about 103 nm after 30 days. The antioxidant tests of the DPPH, ABTS, and lipid peroxide models showed that these CS-SeNPs could scavenge free radicals at different levels. And the 1 month old SeNPs held the higher ABTS scavenging ability that the value could reach up to 87.45 ± 7.63% and 89.44 ± 5.03% of CS(l)-SeNPs and CS(h)-SeNPs, respectively. In the cell test using BABLC-3T3 or Caco-2, the production of the intracellular reactive oxygen species (ROS) could be inhibited in a Se concentration-dependent manner. The topical or oral administration of CS-SeNPs, particularly the Se nanoparticles stabilized with low molecular weight CS, CS(l)-SeNPs, and treated with a 30-day storage process, could efficiently protect glutathione peroxidase (GPx) activity and prevent the lipofusin formation induced by UV-radiation or D-galactose in mice, respectively. Such effects were more evident in viscera than in skin. The acute toxicity of CS(l)-SeNPs was tenfold lower than that of H2SeO3. CONCLUSIONS: Our work could demonstrate the CS-SeNPs hold a lower toxicity and a 30-day storage process could enhance the antioxidant capacities. All CS-SeNPs could penetrate the tissues and perform their antioxidant effects, especially the CS(l)-SeNPs in mice models. What's more, the antioxidant capacities of CS-SeNPs were more evident in viscera than in skin.

[Study on the Synergistic Antioxidant Mechanism of Chlorogenic Acids (CQAs) with Electrochemical and Spectroscopy Property].

The synergistic antioxidant mechanism of chlorogenic acids (CQAs) was studied in this paper through cyclic voltammograms (CV), oil-water partition coefficient (P), FT-IR, XRD and circular dichroism (CD). The antioxidant capability of CQAs isomers and their mixture was determined by using ABTS free radical quenching ability assay. The results showed that the bigger the antioxidant activity disparity between the CQAs molecules was, the higher the content of high antioxidant activity CQAs was, the better the synergistic effect of the CQAs combination mixture became; The oxidation potential (Epa) of CQAs combination mixture kept constant in the synergistic experiments, which indicted the oxidative coupling interaction don't exist between the CQAs; The charge transferred (Q) and antioxidant activity exhibited high correlation (0.92); the practical Q was higher than the theoretical Q in the synergistic process and this confirmed that the CQAs (dicaffeoylquinic acids) regeneration of high antioxidant activity happened; the CQAs mixture with the absolute difference value of oil-water partition coefficient of 0.13 gave the good interface effect and high synergistic degree; the interaction and the regular arrangement between the CQAs combination were not discovered through FT-IR, XRD and CD. Therefore, the regeneration mechanism of CQAs molecules and the interface effect of reaction system were the main cause of the phenomenon of the synergistic antioxidant of CQAs.

Synthesis, characterization, and controlled release of selenium nanoparticles stabilized by chitosan of different molecular weights.

Chitosan-stabilized selenium nanoparticles (SeNPs) have been reported, but there is no information on the effect of the chitosan molecular weight on the structure, stability, and selenium release properties of the SeNPs. Herein, we compared the uniform Se(0) spherical nanoparticles prepared through the reduction of seleninic acid with ascorbic acid in the presence of chitosan with different molecular weights (Mws). We found that both low and high molecular weight chitosan-stabilized selenium nanoparticles exhibited core-shell microstructures with a size of about 103 nm after 30 days growing through the "bottom-up approach" and "top-down approach," respectively. Moreover, both chitosan SeNPs processed excellent stability towards pH and enzyme treatment. In contrast, selenium was easily released to different extents from these two chitosan SeNPs upon treatment with different free radicals. This makes these materials potentially useful as oral antioxidant supplements.