Chuner Cai

A diminutive plant from the Late Silurian of Xinjiang, China

A new diminutive plant, Filiformorama simplexa gen. et sp. nov., is described from the Late Silurian (late Pridoli) Wutubulake Formation of north Xinjiang, China and is placed tentatively in the rhyniophytoids. This plant has naked axes and a dichotomous branching system. A body, interpreted as a sporangium, forms the termination of one branch of a dichotomy, and the other daughter branch continues to grow and dichotomizes further. Most complete sporangia are circular, but some are reniform or tongue-shaped, with an asymmetric base.A new diminutive plant, Filiformorama simplexa gen. et sp. nov., is described from the Late Silurian (late Pridoli) Wutubulake Formation of north Xinjiang, China and is placed tentatively in the rhyniophytoids. This plant has naked axes and a dichotomous branching system. A body, interpreted as a sporangium, forms the terminatation of one branch of a dichotomy, and the other daughter branch continues,to grow and dichotomizes further. Most complete sporangia are circular, but some are reniform or tongue-shaped, with an asymmetric base.

Purification and photodynamic bioactivity of phycoerythrin and phycocyanin from Porphyra yezoensis Ueda

Phycoerythrin and phycocyanin were purified from Porphyra yezoensis Ueda with their bioactivity determined in this study. Continuous precipitation with ammonium sulfate at different concentrations (10%, 20%, 40% and 50%) increased the purity (A564:A280) of phycoerythrin to 1.49, 3.92 fold of the raw extract (0.38) and the purity (A615:A280) of phycocyanin to 0.70, 3.33 fold of the raw extract (0.21). Two more times of chromatography with hydroxylapatites finally made the purity of phycoerythrin and phycocyanin reach 5.50, 14.47 fold of the raw extract, and 5.10, 24.29 fold of the raw extract, respectviely. The yield of high purity phycoerythrin and phycocyanin were 0.21% and 0.09% of dried P. yezoensis blade, respectively. The photodynamic cytotoxic experiment showed that both phycoerythrin and phycocyanin inhibited the growth of liver tumor cells significantly. It was found that 250 mg L−1 purified phycoerythrin and phycocyanin inhibited the growth of hepatocellular carcinoma cells 24 h after laser-irradiation by 80% and 59%, respectively, and 100 mg L−1 purified phycoerythrin and phycocyanin induced the apoptosis of 31.54% and 32.54% of the cells, respectively, 8 h after photodynamic therapy. Oue findings demonstrated that P. yezoensis can serve as photosensitizer (phycoerythrin and phycocyanin) producer.

Purification, crystallization and preliminary X-ray analysis of phycocyanin and phycoerythrin from Porphyra yezoensis Ueda

Porphyra yezoensis is one of the most important and widely cultured seaweeds in China. Phycobiliproteins exhibit excellent spectroscopic properties and play versatile roles in the biomedical, food, cosmetics and chemical synthetic dye industries. Here, the purification and crystallization of phycoerythrin and phycocyanin, two phycobiliproteins extracted from P. yezoensis, are described. Using a novel protocol including co-precipitation with ammonium sulfate and hydroxyapatite column chromatography, both phycobiliproteins were produced on a large scale with improved quality and yield compared with those previously reported. Native PAGE analysis indicated that phycoerythrin and phycocyanin exist as (αβ)(3) heterohexamers in solution. The crystals of phycoerythrin diffracted to 2.07 Å resolution and belonged to space group R3. The unit-cell parameters referred to hexagonal axes are a = b = 187.7, c = 59.7 Å, with nine (αβ)(2) heterotetramers per unit cell. The crystals of phycocyanin diffracted to 2.70 Å resolution in space group P2(1). Matthews coefficient analysis shows that 10-19 (αβ) heterodimers of phycocyanin in the asymmetric unit would be reasonable. A self-rotation function calculation clarified this ambiguity and indicated that 12 (αβ) heterodimers of phycocyanin are assembled in the asymmetric unit.

Optimization of IgG conjugation with R-phycoerythrin from Porphyra yezoensis

To optimize the chemical conjugation between R-phycoerythrin (R-PE) and antibody, different molar ratios of the heterobifunctional reagent N-succinimidyl-3-2-pyridyldithio propionate (SPDP) to R-PE were tested for R-PE derivation into R-PE-PDP, and different molar ratios of dithiothreitol (DTT) to IgG were tested for IgG thiolation. The results showed that in terms of best product yields determined by ultraviolet (UV) spectrophotometry, the optimal molar ratio of SPDP to R-PE was 40:1 for PE derivation, and that of DTT to IgG was 500:1 for thiolation. R-PE-labeled secondary antibody was produced by cross-linking PE-PDP and thiolated IgG. After further purification, UV spectra and native polyacrylamide gel electrophoresis determined its high purity and molecular weight. Finally, in conjunction with antigen-specific first antibodies, the R-PE-labeled IgG was applied in fluorescence immunoassays as secondary antibody and successfully detected antigens spotted on nitrocellulose membrane as well as intracellular antigen in SMCC-7721 cells. This study provides a feasible method of fluorescence antibody preparation from R-PE of Porphyra yezoensis and demonstrates high fluorescent labeling efficiency and good immunologic reactivity of the product.