Bingjun Qian

Applicability of the chymopapain gene used as endogenous reference gene for transgenic huanong no. 1 papaya detection.

The virus-resistant papaya (Carica papaya L.), Huanong no. 1, was the genetically modified (GM) fruit approved for growing in China in 2006. To implement the labeling regulation of GM papaya and its derivates, the development of papaya endogenous reference gene is very necessary for GM papaya detection. Herein, we reported one papaya specific gene, Chymopapain (CHY), as one suitable endogenous reference gene, used for GM papaya identification. Thereafter, we established the conventional and real-time quantitative PCR assays of the CHY gene. In the CHY conventional PCR assay, the limit of detection (LOD) was 25 copies of haploid papaya genome. In the CHY real-time quantitative PCR assay, both the LOD and the limit of quantification (LOQ) were as low as 12.5 copies of haploid papaya genome. Furthermore, we revealed the construct-specific sequence of Chinese GM papaya Huanong no. 1 and developed its conventional and quantitative PCR systems employing the CHY gene as endogenous reference gene. This work is useful for papaya specific identification and GM papaya detection.

Allergenic response to squid (Todarodes pacificus) tropomyosin Tod p1 structure modifications induced by high hydrostatic pressure.

The structural and allergenic modifications of tropomyosin Tod p1 (TMTp1) in fresh squids induced by high hydrostatic pressure (HHP) were investigated. The α-helix in TMTp1 decreased along with increasing pressure from 200 to 600 MPa, where almost 53% α-helix was converted into β-sheet and random coils at 600 MPa. The free sulfhydryl group dropped significantly as pressure went up, but the surface hydrophobicity increased at 200 and 400 MPa, while it slightly decreased at 600 MPa. Based on in vitro gastrointestinal digestion test, digestibility of TMTp1 was promoted by HHP treatment, in which 400 and 600 MPa were more effective in reducing the allergenicity than 200 MPa based on indirect ELISA. This study suggested that HHP can decrease allergenicity of TMTp1 by protein unfolding and secondary structure modification, thus providing potential for alleviating allergenicity of squid.

Quantitative studies on structure-DPPH• scavenging activity relationships of food phenolic acids.

Phenolic acids are potent antioxidants, yet the quantitative structure-activity relationships of phenolic acids remain unclear. The purpose of this study was to establish 3D-QSAR models able to predict phenolic acids with high DPPH• scavenging activity and understand their structure-activity relationships. The model has been established by using a training set of compounds with cross-validated q2 = 0.638/0.855, non-cross-validated r2 = 0.984/0.986, standard error of estimate = 0.236/0.216, and F = 139.126/208.320 for the best CoMFA/CoMSIA models. The predictive ability of the models was validated with the correlation coefficient r2pred = 0.971/0.996 (>0.6) for each model. Additionally, the contour map results suggested that structural characteristics of phenolics acids favorable for the high DPPH• scavenging activity might include: (1) bulky and/or electron-donating substituent groups on the phenol ring; (2) electron-donating groups at the meta-position and/or hydrophobic groups at the meta-/ortho-position; (3) hydrogen-bond donor/electron-donating groups at the ortho-position. The results have been confirmed based on structural analyses of phenolic acids and their DPPH• scavenging data from eight recent publications. The findings may provide deeper insight into the antioxidant mechanisms and provide useful information for selecting phenolic acids for free radical scavenging properties.

Chemical composition, angiotensin-converting enzyme-inhibitory activity and antioxidant activities of few-flower wild rice (Zizania latifolia Turcz.)

BACKGROUND The chemical compositions of the stem and leaf sheath of few-flower wild rice were analysed. In addition, their extracts were evaluated for diphenylpicrylhydrazyl (DPPH) free radical-scavenging activity, ferric-reducing antioxidant power and angiotensin-converting enzyme (ACE)-inhibitory activity, since these are important properties of sources of nutraceuticals or functional foods. RESULTS The stems contained more ascorbic acid (0.06 g kg(-1) fresh weight), protein (28.18 g kg(-1) dry weight (DW)), reducing sugars (308.54 g kg(-1) DW), water-soluble pectin (20.63 g kg(-1) DW), Na(2) CO(3) -soluble pectin (44.14 g kg(-1) DW), K (8 g kg(-1) dry matter (DM), S (6 g kg(-1) DM) and P (5 g kg(-1) DM) but less starch, total dietary fibre, Si, Na and Ca than the leaf sheaths. The DPPH free radical-scavenging IC(50) values of the stem and leaf sheath extracts were 19.28 and 21.22 mg mL(-1) respectively. In addition, the ACE-inhibitory IC(50) value of the stem extracts was 38.54 mg mL(-1). CONCLUSION Both the stem and leaf sheath extracts exhibited good antioxidant properties, while good ACE-inhibitory activity was detected only in the phosphate buffer solution extracts of the stem. Few-flower wild rice could be processed into formula feeds for fish, poultry, etc. or functional foods for persons with high blood pressure.

The effects of gallic/ferulic/caffeic acids on colour intensification and anthocyanin stability

The mechanism by which copigments stabilize colour, by protecting anthocyanin chromophores from nucleophilic attack, seems well accepted. This study was to determine effects of gallic/ferulic/caffeic acids on colour intensification and anthocyanin stability. Molecular dynamics simulations were applied to explore molecular interactions. Phenolic acids intensified the colour by 19%∼27%. Colour fading during heating followed first-order reactions with half-lives of 3.66, 9.64, 3.50, and 3.39h, whereas anthocyanin degradation, determined by the pH differential method (or HPLC-PDA), followed second-order reactions with half-lives of 3.29 (3.40), 3.43 (3.39), 2.29 (0.39), and 2.72 (0.32)h alone or with gallic/ferulic/caffeic acids, respectively, suggesting that anthocyanin degradation was faster than the colour fading. The strongest protection of gallic acids might be attributed to the shortest distance (4.37Å) of its aromatic ring to the anthocyanin (AC) panel. Hyperchromic effects induced by phenolic acids were pronounced and they obscured the accelerated anthocyanin degradation due to self-association interruption.

Characterization of Phytochemicals and Antioxidant Activities of Red Radish Brines during Lactic Acid Fermentation

Red radish (Raphanus L.) pickles are popular appetizers or spices in Asian-style cuisine. However, tons of radish brines are generated as wastes from industrial radish pickle production. In this study, we evaluated the dynamic changes in colour properties, phenolics, anthocyanin profiles, phenolic acid composition, flavonoids, and antioxidant properties in radish brines during lactic acid fermentation. The results showed that five flavonoids detected were four anthocyanins and one kaempferol derivative, including pelargonidin-3-digluoside-5-glucoside derivatives acylated with p-coumaric acid, ferulic acid, p-coumaric and manolic acids, or ferulic and malonic acids. Amounts ranged from 15.5–19.3 µg/mL in total monomeric anthocyanins, and kaempferol-3,7-diglycoside (15–30 µg/mL). 4-Hydroxy-benzoic, gentisic, vanillic, syringic, p-coumaric, ferulic, sinapic and salicylic acids were detected in amounts that varied from 70.2–92.2 µg/mL, whereas the total phenolic content was 206–220 µg/mL. The change in colour of the brine was associated with the accumulation of lactic acid and anthocyanins. The ORAC and Fe2+ chelation capacity of radish brines generally decreased, whereas the reducing power measured as FRAP values was increased during the fermentation from day 5 to day 14. This study provided information on the phytochemicals and the antioxidative activities of red radish fermentation waste that might lead to further utilization as nutraceuticals or natural colorants.

VPPIPP and IPPVPP: two hexapeptides innovated to exert antihypertensive activity.

In this study, two hexapeptides of IPPVPP and VPPIPP were innovated by using two commercial antihypertensive peptides IPP and VPP as two domains cis-linked and trans-linked, respectively. The IPPVPP and VPPIPP were chemically synthesized and evaluated for the antihypertensive activity in vitro/vivo. The in vitro ACE-inhibitory study showed that VPPIPP (34.71±4.38%) has a significantly stronger activity than that of IPPVPP (13.17±0.25%) at a treatment concentration of 10 µmol/L, but it was weaker than the commercial IPP (56.97±2.40%) (P<0.05). However, VPPIPP, IPPVPP, and IPP lowered the systolic blood pressure by 21±0.9%, 17.4±1.3% and 17.5±0.9%, respectively, in rats at 1.5 mg/kg body weight dosage. The result was consistent with the mRNA level of sarcoplasmic reticulum Ca2+, Mg2+ -ATPase Gene (SERCA 2a) in rat hearts. Additionally, VPPIPP and IPPVPP showed no negative impact on blood glycometabolism. The results suggested that the two hexapeptides could be potent bioactive peptides in functional foods for people with high blood pressure.

Effects of Vitamin B6 Deficiency on the Composition and Functional Potential of T Cell Populations

The immune system is critical in preventing infection and cancer, and malnutrition can weaken different aspects of the immune system to undermine immunity. Previous studies suggested that vitamin B6 deficiency could decrease serum antibody production with concomitant increase in IL4 expression. However, evidence on whether vitamin B6 deficiency would impair immune cell differentiation, cytokines secretion, and signal molecule expression involved in JAK/STAT signaling pathway to regulate immune response remains largely unknown. The aim of this study is to investigate the effects of vitamin B6 deficiency on the immune system through analysis of T lymphocyte differentiation, IL-2, IL-4, and INF-γ secretion, and SOCS-1 and T-bet gene transcription. We generated a vitamin B6-deficient mouse model via vitamin B6-depletion diet. The results showed that vitamin B6 deficiency retards growth, inhibits lymphocyte proliferation, and interferes with its differentiation. After ConA stimulation, vitamin B6 deficiency led to decrease in IL-2 and increase in IL-4 but had no influence on IFN-γ. Real-time PCR analysis showed that vitamin B6 deficiency downregulated T-bet and upregulated SOCS-1 transcription. This study suggested that vitamin B6 deficiency influenced the immunity in organisms. Meanwhile, the appropriate supplement of vitamin B6 could benefit immunity of the organism.

Use of Sodium Dodecyl Sulfate Pretreatment and 2-stage Curing for Improved Quality of Salted Duck Eggs

UNLABELLED The effects of use of sodium dodecyl sulfate (SDS) pretreatment and 2-stage curing on the microbial, physicochemical, and microstructural qualities of salted duck eggs were studied. After pretreatment in 0.5% (w/v) SDS solution at room conditions for 15 min, no discolorations were observed and no microorganisms were detected on the egg shells. In the 2-stage curing process, 25% (w/v) and 30% (w/v) saline solutions were evaluated in the 1st step (Stage I, approximately 18 d), whereas 4% (w/v) saline solution was applied in the 2nd step (Stage II, approximately 15 d). Along with increased curing time, water content decreased and NaCl content increased in the egg yolks from approximately 0.40% to 0.86%, whereas the water content of egg albumen remained at approximately 85% during the 2-stage curing. More importantly, the NaCl content of albumen maintained at approximately 4.0% at Stage II curing. Yolk index as a sign of maturity for salted duck eggs reached 1 at the end of Stage I (18 d) and retained the same value during Stage II curing regardless of the NaCl concentration in the Stage I saline solution. Oil exudation in egg yolks increased as the time of curing increased. As seen from scanning electron microscopy, oil was released from yolk granules. This study indicated that SDS pretreatment is effective to reduce microbial load on the shells of fresh duck eggs and the 2-stage curing can improve physicochemical qualities of the salted duck eggs and shortened curing time to about 7 to 17 d as compared to the traditional 1-step curing method. PRACTICAL APPLICATION Spoiled saline solution and uneven distribution of salt are the 2 major problems in producing salted duck eggs. Sodium dodecyl sulfate (SDS) pretreatment and 2-stage curing process have shown effective to solve these problems, respectively. The SDS pretreatment was able to remove microorganisms and soil from the surface of fresh egg shells, thus preventing the spoilage of the saline solution. The 2-stage curing process successfully controlled the NaCl content of egg albumen and yolk in the final product, and shortened the curing time compared to the traditional 1-step curing method.

Effect of complexes of cyanidin-3-diglucoside-5-glucoside with rutin and metal ions on their antioxidant activities

Studies have enabled a molecular understanding of the anthocyanin copigmentation phenomenon over several decades. However, the effect of combinations of, or even supramolecular assemblies of, anthocyanins with other phenols and/or metal ions on their antioxidative activity was unclear. In this study, anthocyanin complexes of cyanidin-3-diglucoside-5-glucoside (CY3D5G), rutin and Mg(II)/Fe(III) were constructed, analyzed, and evaluated for their antioxidant effects. The CY3D5G-rutin-Fe(III) exhibited supramolecular properties via visible, CD and FTIR spectra among complexes. The interaction of CY3D5G-rutin, CY3D5G-rutin-Mg(II), or CY3D5G-rutin-Fe(III) was synergistic (P<0.05) in the ORAC assay. On cellular ROS levels, the median effective concentration of the CY3D5G-rutin-Mg(II) was 7.76μmol QE/L and exhibited a synergistic interaction (CI=0.67, P<0.05), whereas the CY3D5G-rutin-Fe(III) (CI=0.79, P=0.074) was additive. The results indicate that the antioxidant properties were affected by the molecular combination. Additionally, Fe(III) might exhibit a negative effect, since the CY3D5G-Fe(III) required a greater concentration than CY3D5G to achieve the same effect on cells.