Formation of primary pit connection during conchocelis phase of Porphyra yezoensis （Bangiophyceae, Rhodophyta）

1 INTRODUCTION Pit connection is an important feature in Rhodophyta and significant in algal phylogeny. Various documents have illustrated the existence of pit-connection in red alga previously (Migita, 1967; Ramus 1969a, b; Bourne et al., 1970; Lee and F…     

Cloning and Analysis of Calmodulin Gene from Porphyra yezoensis Ueda （Bangiales, Rhodophyta）

In order to understand the mechanisms of signal transduction and anti-desiccation mechanisms of Porphyra yezoensis, cDNA and its genomic sequence of Calmodulin gene (CaM) was cloned by the technique of polymerase chain reaction (PCR) based on the analysis of P. yezoensis ESTs from dbEST database. The result shows that the full-length cDNA of CaM consists of 603 bps including an ORF encoding for 151 amino acids and a terminate codon UGA, while the length of genomic sequence is 1231 bps including 2 exons and 1 intron. The average GC content of the coding region is 58.77%, while the GC content of the third position of this gene is as high as 82.23%. Four Ca²⁺ binding sites (EF-hand) are found in this gene. The predicted molecular mass of the deduced peptide is 16688.72 Da and the pI is 4.222. By aligning with known CaM genes, the similarity of CaM gene sequence with homologous genes in Chlamydomonas incerta and Chlamydomonas reinhardtii is 72.7% and 72.2% respectively, and the similarity of the deduced amino acid sequence of CaM gene with homologous genes in C. incerta and C. reinhardtii are both 71.5%. This is the first report on CaM from a species of Rhodophyta.     

Expression of the Phycoerythrin Gene of Gracilaria lemaneiformis （Rhodophyta） in E. coil and Evaluation of the Bioactivity of Recombinant PE

Phycoerythrin (PE) is one of the most important proteins involved in light capturing during photosynthesis in red algae. Its potential biological activities had gained wide concerns. In the present study, tumor cytotoxic and hydroxyl radical assay were preformed to detect the bioactivity of recombinant PE. Recombinant plasmids pGEX-PE and pBGL were transformed into E. coli BL21 to make two recombinant strains BEX (pGEX-PE) and BGL (pBGL). PE expressing in BEX (pGEX-PE) was validated by SDS-PAGE and Western blotting analysis. SDS-PAGE analysis indicated that the PE-GST fusion protein was mostly inclusion bodies. Specific expression of PE was confirmed by Western blotting analysis. The recombinant E. coli BEX (pGEX-PE) cells were collected and sonicated. The supernatants were reserved for the tumor cytotoxic experiments. The result of tumor cytotoxic assay indicated that the supernatants containing PE had the activity of inhibiting the growth of Hela cells and with the increase of protein concentration, the inhibiting rate increased from 37.31% to 63.26%, which showed significant difference from the control. Hydroxyl radical scavenging effect was tested with supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates treated with sonication and heating. For the sonication samples, the scavenging rates of the supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates were significantly higher than the negative control BL21(pGEX-4T) (P<0.02), and the scavenging rates increased slowly following the increase of the protein content. For the heating samples, except for the 0.2 mg mL⁻¹ BGL (pBGL) products, the scavenging effects of the supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates were stronger than that of negative control BL21(pGEX-4T). However, the effect intensity was not positively correlated with the increase of the protein concentration. Though a partially decreased hydroxyl radical scavenging activity was led by heating, the biological activity was still retained and conspicuous. This research showed that phycoerythrin protein expressing in E. coli has the potential medical and sanitarian value.     

Observation of female gamete (Carpogonia) germination of Porphyra yezoensis and P. oligospermatangia

Several papers have reported that part or whole leafy thallus seemingly consisting of zygotospores can give rise to both blades and conchocelis in the same culture ofPorphyra. Study on samples of wild and cultivatedPorphyra yezoensis andP. oligospermatangia were conducted to clarify the origination of the young blades in the culture. It is confirmed that single cells on the blade of both species, which normally intermixed with zygotospores, germinated into young blades. TEM and SEM observation has shown that the single cells ofPorphyra yezoensis had typical features of female gamete (carpogonia) but archeospore. Therefore, the female gametes are responsible in developing leafy thalli. This project was sponsored by the NSFC (No. C-0205-05-39770593)     

Study on cryopreservation of Porphyra yezoensis conchocelis

Cryopreservation of Porphyra yezoensis conchocelis was conducted with cryoprotectants and a proposed pretreatment procedure and thawing methods explored. Six cryoprotectants combined by DMSO with ethylene glycol （EG）, propylene glycol （PEG）, sorbitol and sucrose were developed. The effect of prefreezing at -40℃ or -20℃ for different time durations was compared and the thawing methods were screened. It was shown that the cryoprotectant including 10% DMSO with 0.5 molL^-1 sorbitol exhibited the optimal effect. The ideal pretreatment was that conchocelis segments were stayed for 20min at -40℃ before stored in liquid nitrogen, and 40℃ water bath was proper for quick thawing. The highest recovery rate of cryopreserved P. yezoensis conchocelis reached 89.41%.     

Cloning and Analysis of Calmodulin Gene from Porphyra yezoensis Ueda (Bangiales, Rhodophyta)

In order to understand the mechanisms of signal transduction and anti-desiccation mechanisms of Porphyra yezoensiss,cDNA and its genomic sequence of Calmodulin gene (CaM) was cloned by the technique of polymerase chain reaction (PCR) based on the analysis of P. yezoensis ESTs from dbEST database. The result shows that the full-length cDNA of CaM consists of 603 bps including an ORF encoding for 151 amino acids and a terminate codon UGA, while the length of genomic sequence is 1231 bps including 2 exous and 1 intron. The average GC content of the coding region is 58.77%, while the GC content of the third position of this gene is as high as 82.23%. Four Ca2+ binding sites (EF-hand) are found in this gene. The predicted molecular mass of the deduced peptide is 16688.72 Da and the pI is 4.222. By aligning with known CaM genes, the similarity of CaM gene sequence with homologous genes in Chlamydomonas incerta and Chlamydomonas reinhardtii is 72.7% and 72.2% respectively, and the similarity of the deduced amino acid sequence of CaM gene with homologous genes in C. incerta and C. reinhardtii are both 71.5%. This is the first report on CaM from a species of Rhodophyta.     

The influence of Fe~(2+) on growth and development of cells enzy-matically isolated from Porphyra yezoensis blades

1 INTRODUCTION Porphyra (also called nori in Japanese) is one of the most important algae in aquaculture in the world. In the early 1980’s, basic studies on cell and protoplast isolation, cultivation and “seedling” breeding of Porphyra were conducted in laboratory. Zhao and Zhang (1981) isolated and cultured isolated cells by grinding the nori thallus, and Lu (1983) isolated cells by digesting bacteria. An enzyme isolated from a sea snail, was used to isolate cells and protoplasts (T…     

Construction of Porphyra yezoensis Pure Line from Protoplasts and Its 18S rDNA Sequence Determination

1　Introduction　PorphyraisthemainobjectforalgafarmingandplaysaveryimportantroleinChinesemarineindus tries.Recently ,therehasbeenagreatlossinPor phyracultivationduetothedegenerationoftheculti var,sothereisanincreasingdemandforgoodPor phyracultivars .Theprerequisiteofthetraditionalbreed ingandbioengineeringresearchofPorphyraistheconstructionofpurelines .Traditionally ,theclassifi cationofPorphyrawasaccordingtotheirmorphologi calcharacteristics .However ,mostmorphologicalfea turesofPorphyraar…     

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 phy-cocyanin 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 ex-periment 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.     

Ultrastructure of Single Cells, Callus-like and Monospore-like Cells in Porphyra yezoensis Ueda on Semi-solid Culture Medium

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Ultrastructure of Single Cells, Callus-like and Monosore-like Cells in Porphyra yezoensis Ueda on Semi solid Culture Medium

It had been demonstrated that individual cells or protoplasts isolated from Porphyra thallus by enzyme could develop into normal leafy thalli in the same way as monospores, and that isolated cells develop in different way in liquid and on semi solid media. The authors observed the ultrastructure of isolated vegetative cells cultured on semi solid media and compared them with those of monospores and isolated cells cultured in liquid media. The results showed that subcellular structures were quite different among cells in different conditions. In their development, isolated cells on semi solid media did not show the characteristic subcellular feature of monospore formation, such as production of fibrous vesicles. Callus like cells formed on semi solid media underwent a distinctive modification in cellular organization. They developed characteristic cell inclusions and a special 2 layer cell covering. Golgi bodies, ER, starch grains, mitochondria. Vacuoles were not commonly found in them.