Qinzhao Xue

Identification and characterization of an intracellular Cu, Zn-superoxide dismutase (icCu/Zn-SOD) gene from clam Venerupis philippinarum

Superoxide dismutase (SOD, EC 1.15.1.1) represents one kind of enzyme involved in scavenging the high level of reactive oxygen species (ROS) into molecular oxygen and hydrogen peroxide. In the present study, the intracellular Cu/Zn-SOD gene (icCu/Zn-SOD) of Venerupis philippinarum (denoted as VpSOD) was identified from haemocytes by homology cloning and RACR approaches. The full-length cDNA of VpSOD consisted of 910 nucleotides with a canonical polyadenylation signal sequence AATAAA, a polyA tail, and an open-reading frame of 465 bp encoding 154 amino acids. The deduced amino acid of VpSOD shared high similarity with the icCu/Zn-SODs from other species, indicating that VpSOD should be a new member of icCu/Zn-SOD family. Several highly conserved motifs including Cu, Zn binding sites (H(46), H(48), H(63), H(120) for Cu binding, and H(63), H(71), H(80), D(83) for Zn binding), intracellular disulfide bond and two Cu, Zn SOD signatures were also identified in VpSOD. The temporal expression of VpSOD in haemocytes after Vibrio anguillarum challenge was recorded by quantitative real-time RT-PCR. The relative expression level of VpSOD mRNA was up-regulated rapidly at 6 h post-infection and reached 18-fold of the control group. After a drastic decrease at 12 h, the expression level increased again and reached 22-fold to that in the control group at 96 h post-infection. All these results indicated that VpSOD was an acute-phase protein involved in the immune responses of V. philippinarum.

Synthesis and moisture absorption and retention activities of a carboxymethyl and a quaternary ammonium derivative of α,α-trehalose

Carboxymethyl alpha,alpha-trehalose (CMT) and a quaternary ammonium derivative of alpha,alpha-trehalose (QT) were successfully prepared, and their moisture absorption and retention activities were assessed. Results showed that both CMT and QT had better moisture absorption abilities at 43% and 81% relative humidity (RH) than alpha,alpha-trehalose. In addition, the two alpha,alpha-trehalose derivatives had better moisture retention abilities than alpha,alpha-trehalose under three humidity conditions: 81% RH, 43% RH, and under dry conditions. Therefore, carboxymethylation and quaternarization could improve the moisture absorption and retention abilities of alpha,alpha-trehalose. CMT and QT showed better moisture absorption ability and moisture retention ability than that of hyaluronan (HA), and could potentially find a use as moisture retention ingredient, for example, in cosmetics.

The Moisture Absorption and Retention Abilities of Hyaluronan, Chitosan, Starch and Their Quaternary Derivatives

Quaternary ammonium salt of hyaluronan (QHA), quaternary ammonium salt of starch (QS), and quaternary ammonium salt of chitosan (QCTS) were successfully prepared. Infrared spectroscopy (IR), 1H NMR and 13C NMR techniques were used to characterize the molecular structure of QHA. Results showed that QHA had better moisture absorption abilities than HA both at 43% and 81% RH. QS and QCTS had the same tendency. In addition, the three quaternized polysaccharides had better moisture retention abilities than their corresponding polysaccharides under three humidity conditions: 81% RH, 43% RH and dry condition. The -N+ (CH 3 ) 3 group played a very important role in moisture-absorption and retention ability of the quaternized polysaccharides. QCTS and QHA showed parallel or better R a and R h than that of HA, and had potential to use as moisture-retention ingredient, e. g., in cosmetics.

Synthesis of Water-Soluble Quaternized Chitosans and Their Antitumor Activity

water-soluble low-molecular-weight chitosan(LCTS) was prepared by hydrogen peroxide oxidation method and their quaternized derivatives(QLCTS) was also synthesized using previous methods. Their antitumor activity was studied, and the results showed that the LMW and its quaternized derivatives inhibited the growth of pancreatic carcinoma cell strain PANC-1 in vitro, and the inhibitory rate reached 59.2%.

The Influence of Amino and Hydroxyl of Chitosan on Hydroxyl Radical Scavenging Activity

In order to determine the effect of the amido and hydroxyl of chitosan on antioxidant activity, a series of N-deacetylated chitosan with a degree of deacetylation (D.D.) ranging from 45% to 95% were prepared using region selective N-acetylation of chitosan. Their carboxymethyl derivatives (CMC) were also synthesized according to previous method. The antioxidant activity was evaluated on the basis of their abilities to scavenge hydroxyl radical. The results indicated that the hydroxyl radical scavenging ability depended on the degree of deacetylation and concentration. It also showed that the 2-NH 2 had a closer relation than 6-OH in hydroxyl radical scavenging activities. c2009 Crown.