Subunit composition and chromophore content of R-phycoerythrin fromPorphyra haitanensis

R-phycoerythrin fromPorphyra haitanensis exists in two aggregation states with different molecular weights. A more highly aggregated form, RPE I, was chromatographed on Bio-Rex 70 column with urea solution (pH 3.0) as eluent, and the molecular weights of the 3 subunits (α, β, γ) obtained were determined on SDS-PAGE at 18000, 19200 and 30000, respectively. α subunit carried two phycoerythrobilin (PEB); β subunit, three PEB and one phycourobilin (PUB); γ subunit, one PEB and three PUB chromophores. The molar ratio of α, β, and γ subunits of RPE I was 6: 6: 1, and their subunit composition was confired to be (αβ)₆γ on account of the molecular weight of RPE I, 232000. A lower aggregated form, RPE II, contained α and β subunits similar to those of RPE I, but its subunit composition was the (αβ) monomer of RPE. Contribution No. 2108 from the Institute of Oceanology, Chinese Academy of Sciences     

Comparative studies on structural feature of agar polysaccharides fromPorphyra haitanensis grown in south and north China

The structural feature of agar polysaccharides fromPorphyra haitanensis grown in south China and transplanted to the north was investigated by fractionation on DEAE—Sephadex A 50, chemical analysis, and infrared and¹³C-NMR spectroscopy. The agars composed mainly of charged molecules were eluted from DEAE—Sephadex A 50 with 1.0 mol/L NaCl solution from the southernP. haitanensis and with 0.5 mol/L NaCl from the northern one. The¹³C-NMR spectra showed that agarobiose [(1→3)-β-D-galactopyranosyl-(1→4)-3,6-anhydro-α-L-galactopyranose] and the biological precursor of agarobiose [(1→3)-β-D-galactopyra nosyl-(1→4)-6-sulfate-α-L-galactopyranose] were the major disaccharide repeating units in the charged fractions. The content of the biological precursor in the agar polysaccharides from southernP. haitanensis was higher than that in the northern one, the content of the biological precursor extracted from cold water was higher than that from hot water, and the content of 6-OMe-D-galactose in the southernP. haitanensis polysaccharides was higher than in the northern one. This distinct difference will be of significance for further study of the physiological characters ofP. haitanensis. Contribution No. 1849 from the Institute of Oceanology, Academia Sinica.     

The influence of Fe^2＋ on growth and development of cells enzymatically isolated from Porphyra yezoensis blades

Fe^2＋ acted as an accessorial factor for many cellular enzymatic reactions is very important for seaweed growth and development, but the Fe^2＋ requirement in nori had not been seen. Porphyra yezoensis cells were separated enzymatically and cultured in a series of sterilized seawater media containing various concentrations of Fe^2＋. The growth development and cell were investigated in this work. Through this experiment, two biologically-meant concentration scales were found, one is low concentrations, 12.1-102.1μg/L, 10-100 times than that in seawater, favoring the development of isolated cells of Porphyra and the other was high concentrations, more than 10mg/L inhibiting the cell growth, leading to the deformity and shrinkage of the cells. At the concentration of 50 mg/L, the cells stopped growing and died eventually.     

Isolation and cultivation of the vegetative cells ofPorphyra haitanensis

This research deals mainly with the use of the vegetative cells of a marine red algaPorphyra haitanensis (laver) as seeds and their culture into young thalli for further cultivation in the sea. The experimental process was as follows. Enzymatically isolated vegetative cells were attached to rope substrates and cultured in the laboratory for a month until they became about 0.2–0.5 cm long sporelings and were then attached (7–15 sporelings per cm of rope) to nets for removal to the open sea for cultivation. A month after culturing, the thalli reached a maximum length of 50 cm (average of 20–30 cm). The thalli grew faster as the water temperature dropped from 21°C to 17°C. It was proved that the vegetative cells isolated from a small thallus about 5 cm long could grow up into normal thalli after being kept frozen for a year. The results of this study show that vegetative cells can be used as new seeds to simplify the production of laver sporelings. This technique is a significant advance in the field ofPorphyra culture.     

Early stage differentiation of thallus cells ofPorphyra haitanensis (Rhodophyta)

The early stage differentiation of thallus cells ofPorphyra haitanensis T. J. Chang et B. F. Zheng was studied. Protoplasts or single cells were isolated from the blades using enzyme mixture comprising 2% sea snail gut enzyme and 1% cellulase. The isolated protoplasts or single cells were incubated in the MES medium. The cell differentiations were examined under the microscope at intervals after incubation. Four types of cell differentiation, namely, normal, abnormal, carposporangial and spermatorangial, and rhizoidal types, were observed. Since normal cell differentiations occur mostly in small thalli 50 mm in length and middle portions of big thalli 200 mm in length, it is essential to select tissues from these two kinds of thalli essential for commercial production.     

Ultrastructure of Single Cells ,Callus—like and Monos—pore—like Cells in Porphyra yezoensis Ueda on Semi—slid Culture Medium

It had been demonstrated that individual or protoplasts isolated from Porphyra thallus by enzyme could develop into normal leafy thalli in the same way as monosproes,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 struce-tures were quite different among cells in different conditions.In their development,isolated cells on semi-solid media did not show the characteristic subcellular eature 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,Vaculoes were not commonly found in them.     

On microbial community of Pyropia haitanensis by metagenomic analysis

Microorganisms plays an important role in the growth of Pyropia haitanensis. To understand the structural and functional diversity of the microorganism community of P. haitanensis(PH40), the associated metabolic pathway network in cluster of orthologous groups(COG) and Kyoto Encyclopedia of Genes and Genomes(KEGG), and carbohydrate-active enzymes(CAZymes) were explored in metagenomic analysis. DNA extraction from gametophytes of P. haitanensis was performed first, followed by library construction, sequencing, preprocessing of sequencing data, taxonomy assignment, gene prediction, and functional annotation. The results show that the predominant microorganisms of P. haitanensis were bacteria(98.98%), and the phylum with the highest abundance was Proteobacteria(54.64%), followed by Bacteroidetes(37.92%). Erythrobacter(3.98%) and Hyunsoonleella jejuensis(1.56%) were the genera and species with the highest abundance of bacteria, respectively. The COG annotation demonstrated that genes associated with microbial metabolism was the predominant category. The results of metabolic pathway annotation show that the ABC transport system and two-component system were the main pathways in the microbial community. Plant growth hormone biosynthesis pathway and multi-vitamin biosynthesis functional units(modules) were the other important pathways. The CAZyme annotation revealed that the starch might be an important carbon source for microorganisms. Glycosyl transferase family 2(GT2) and glycosyl transferase family 3(GT3) were the highly abundant families in glucoside transferase superfamily. Six metagenome-assembled genomes containing enzymes involved in the biosynthesis of cobalamin(vitamin B 12) and indole-3-acetic acid were obtained by binning method. They were confirmed to belong to Rhodobacterales and Rhizobiales, respectively. Our findings provide comprehensive insights into the microorganism community of Pyropia.     

Development of suspended conchocelis ofPorphyra haitanensis (Bangiales, Rhodophyta)

This Mar. 1993 to Aug. 1994 study on suspended conchocelis ofPorphyra haitanensis showed that there were three patterns for development of vegetative filaments: filaments to filaments by “budding”; filaments to sporangial branchlets by “budding”, or cell swelling. There were also three patterms for sporangial branchlet development: vegetatively propagating, changing into conchospores, or dying. Each developmental stage had one or more different developmental directions between vegetative filaments and sporangial branchlets. Developments from conchosporangial branchlets to conchospores were sequential and irreversible. Although sporangial branchlets formed at 29°C could give rise to filaments, they could not propagate as healthily under the same conditions as those formed at 25°C did. Probably the crucial period of plant cell differentiation is in the late stage of sporangial branchlets. In line with the developmental directions of different stages, the authors regulated the development of conchocelis to get ideal different developmental stages materials to obtain very developmentally homogeneous stages, including filaments and sporangial branchlets. Contribution No 3283 from the Institute of Oceanology, Chinese Academy of Sciences. Study supported by the Climbing Project B PD-B6-4-2 of the State Science and Technology Commission of China.     

Pyropia haitanensis polysaccharide extends lifespan by inhibiting protein aggregation in Caenorhabditis elegans

Pyropia haitanensis poly saccharide(LP) have been found for having many excellent functions such as anti-aging.Using Caenorhabditis elegans models,we evaluated the anti-aging activity of LP by observing the lifespan,reproduction,pharyngeal pumping,stress response,quantitative fluorescence of poly glutamic acid,and nuclear localization of DAP-16 of worms.The results reveal that LP could extend the adult lifespan of wild-type and polyQ nematodes,indicating a connection of its anti-aging benefit with the toxicity-suppressing effect The number of polyglutamic acid aggregates in high concentration groups decreased by 24.39%(P0.05) to the control.The high-dose group strongly induced DAP-16 nuclear translocation over intermediate and cytosolic localizations compared with the control(P0.001).Therefore,we believe that LP could extend the lifespan and reduce the protein aggregation in C.elegans through nuclear DAF-16::GFP expression.     

In vitro Antioxidant Effects of Porphyra haitanensis Peptides on H_2O_2-Induced Damage in HepG2 Cells

In this study,protein from Porphyra haitanensis was used as raw material to prepare an antioxidant peptide,and its antioxidant activity was evaluated in vitro.A model of H_2O_2-induced oxidative damage in Hep G2 cells was established,and the effects of Porphyra haitanensis hydrolysates (PHHs) on superoxide dismutase (SOD) activity and malondialdehyde (MDA) content were detected.Finally,the structure of PHHs was identified by ESI-MS/MS.The results showed that the 1,1-diphenyl-2-pyridylhydrazine(DPPH)-free radical-scavenging ability of PHHs was the strongest (59.28%at 1.0 mg m L~(-1)) when hydrolyzed with an acidic protease for 4 h.PHHs with different concentrations had protective effects on H_2O_2-induced damage to Hep G2 cells,and the protective effect was enhanced with increasing concentrations.When the level was 400μg m L~(-1),the cell survival rate was as high as 88.62%.Moreover,PHHs can significantly reduce oxidative damage to Hep G2 cells by H_2O_2,improve SOD activity,and reduce MDA content.The tetrapeptide Asp-Lys-Ser-Thr,with a molecular weight of 448 Da,was identified as an important fraction of PHHs by high-resolution mass spectrometry.     

Identification and bioinformatics analysis of micro RNAs from the sporophyte and gametophyte of Pyropia haitanensis

Pyropia haitanensis(T.J.Chang et B.F.Zheng) N.Kikuchi et M.Miyata( Porphyra haitanensis) is an economically important genus that is cultured widely in China.P.haitanensis is cultured on a larger scale than Pyropia yezoensis,making up an important part of the total production of cultivated Pyropia in China.However,the majority of molecular mechanisms underlying the physiological processes of P.haitanensis remain unknown.P.haitanensis could utilize inorganic carbon and the sporophytes of P.haitanensis might possess a PCK-type C 4-like carbon-fixation pathway.To identify micro RNAs and their probable roles in sporophyte and gametophyte development,we constructed and sequenced small RNA libraries from sporophytes and gametophytes of P.haitanensis.Five micro RNAs were identified that shared no sequence homology with known micro RNAs.Our results indicated that P.haitanensis might posses a complex s RNA processing system in which the novel micro RNAs act as important regulators of the development of different generations of P.haitanensis.     

Identification of potential internal control genes for real-time PCR analysis during stress response in Pyropia haitanensis

Pyropia haitanensis has prominent stress-resistance characteristics and is endemic to China. Studies into the stress responses in these algae could provide valuable information on the stress-response mechanisms in the intertidal R hodophyta. Here, the ef fects of salinity and light intensity on the quantum yield of photosystem II in P y. haitanensis were investigated using pulse-amplitude-modulation fluorometry. Total RNA and genomic DNA of the samples under dif ferent stress conditions were isolated. By normalizing to the genomic DNA quantity, the RNA content in each sample was evaluated. The c DNA was synthesized and the expression levels of seven potential internal control genes were evaluated using q RT-PCR method. Then, we used ge Norm, a common statistical algorithm, to analyze the q RT-PCR data of seven reference genes. Potential genes that may constantly be expressed under dif ferent conditions were selected, and these genes showed stable expression levels in samples under a salinity treatment, while t ubulin, glyceraldehyde-3-phosphate dehydrogenase and actin showed stability in samples stressed by strong light. Based on the results of the pulse amplitude-modulation fluorometry, an absolute quantification was performed to obtain gene copy numbers in certain stress-treated samples. The stably expressed genes as determined by the absolute quantification in certain samples conformed to the results of the ge Norm screening. Based on the results of the software analysis and absolute quantification, we proposed that e longation factor 3 and 18 S ribosomal RNA could be used as internal control genes when the P y. haitanensis blades were subjected to salinity stress, and that α-tubulin and 18 S ribosomal RNA could be used as the internal control genes when the stress was from strong light. In general, our findings provide a convenient reference for the selection of internal control genes when designing experiments related to stress responses in Py. haitanensis.     

Studies on color type variants from mutagenized protoplasts ofPorphyra haitanensis Chang et Zheng &P. Yezoensis ueda (rhodophycease)

Isolated protoplasts from thalli ofPorphyra haitanensis andPorphyra yezoensis were treated with colchicine or irradiated by ultraviolet (UV). Several types of color variants were observed among the protoplast offspring. After treatment with colchicine: (1) 0.04–0.09% of red type variants inP. haitanensis were obtained; (2) The rate of red type variants and the variegated chimeral thalli composed of red type and wild type of sectors were 0.31–1.11% inP. yezoensis. After irradiation with UV: (1) 3.5–10.5% of red type variants inP. yezoensis were obtained: (2) 0.5–2.0% of red type variants and the variegated chimeral thalli composed of red type and wild type of sectors were obtained inP. haitanensis. Colchicine and UV’s mutangenic effects onP. yezoensis protoplasts were stronger than those onP. haitanensis protoplasts. The most efficient concentration of colchicine was 0.05%. The optimal length of UV-radiation was 1/2 min (radiation distance 5 cm). The red type variants induced by colchicine treatment grew faster than the wild type thalli. The clones of vegetative propagation from protoplasts of red type variants were still red type thalli. The red type variants will be good materials for genetic studies and improvement ofPorphyra strains.     

Studies on intercropping ofPorphyra haitanensis T. J. Chang et B. F. Zheng with Bay ScallopArgopecten irradians Lamarck

Results of the experiment of northward transplantation ofPorphyra haitanensis showed that intercrop ofP. haitanensis with Bay Scallop is feasible because the growth duration of both of them is about the same in August–December. Full use of cultivating area, lowering its cost and increasing its product per unit area as well as improving the ecological environment are realized during intercrop. Contribution No. 2152 from the Institute of Oceanology, Academia Sinica.     

Effects of elevated CO2 on the photosynthesis and nitrate reductase activity of Pyropia haitanensis (Bangiales,Rhodophyta) grown at different nutrient levels

Pyropia haitanensis,a commercially important species,was cultured at two CO2 concentrations(390×10- 6 and 700×10-6(parts per million)) and at low and high nutrient levels,to explore the effect of elevated CO2 on the species under nutrient enrichment. Results show that in CO2-enriched thalli,relative growth rate(RGR) was enhanced under nutrient enrichment. Elevated CO2 decreased phycobiliprotein(PB) contents,but increased the contents of soluble carbohydrates. Nutrient enrichment increased the contents of chlorophyll a(Chl a) and PB,while soluble carbohydrate content decreased. CO2 enrichment enhanced the relative maximum electronic transport rate and light saturation point. In nutrient-enriched thalli the activity of nitrate reductase(NRA) increased under elevated CO2. An instantaneous pH change in seawater(from 8.1 to 9.6) resulted in reduction of NRA,and the thalli grown under both elevated CO2 and nutrient enrichment exhibited less pronounced reduction than in algae grown at the ambient CO2. The thermal optima of NRA under elevated CO2 and/or nutrient enrichment shifted to a lower temperature(10–15°C) compared to that in ambient conditions(20°C). We propose that accelerated photosynthesis could result in growth increment. Nassimilation remained high in acidified seawater and refl ected increased temperature sensitivity in response to elevated CO2 and eutrophication.     

Biofilm formation under high temperature causes the commensal bacteria Bacillus cereus WPySW2 to shift from friend to foe in Neoporphyra haitanensis in vitro model

Although biofilm formation may promote growth, biofilms are not always beneficial to their hosts. The biofilm formation characteristics of Bacillus cereus WPySW2 and its changes at different temperatures were studied. Results show that B. cereus WPySW2 promoted the growth of Neoporphyra haitanensis (an economically cultivated seaweed) at 20 °C but accelerated algal rot at 28 °C. Thicker B. cereus WPySW2 biofilms covered the surface of N. haitanensis thalli at 28 °C, which hindered material exchange between the algae and surrounding environment, inhibited algal photosynthesis and respiration, and accelerated algal decay. Compared with planktonic bacteria, mature biofilm cells had lower energy consumption and metabolic levels. The biofilm metabolic characteristics of B. cereus WPySW2 changed significantly with temperature. High temperature accelerated biofilm maturation, which made it thicker and more stable, allowing the bacteria to easily adapt to environmental changes and obtain greater benefits from their host. High temperature did not affect the production or increased the abundance of toxic metabolites, indicating that the negative effects of B. cereus WPySW2 on algae were not caused by toxins. This study shows that increased temperature can transform a harmless bacterium into a detrimental one, demonstrating that temperature may change the ecological function of phycospheric bacteria by affecting their morphology and metabolism.

     

Toxic effects of Karenia mikimotoi extracts on mammalian cells

Karenia is one of the most harmful and representative red tide genus in a temperate zone. Blooms caused by this genus have resulted in massive fish death in the South China Sea and the East China Sea. However, the potential effects of this dinoflagellate on human health through the transfer of toxins via marine food webs, and the mechanisms of toxicity, are still unknown. Therefore, we examined the toxic effects of a strain of K. mikimotoi (isolated from the South China Sea) on the proliferation and morphol...     

Toxic effects of Karenia mikimotoi extracts on mammalian cells

Karenia is one of the most harmful and representative red tide genus in a temperate zone. Blooms caused by this genus have resulted in massive fish death in the South China Sea and the East China Sea. However, the potential effects of this dinoflagellate on human health through the transfer of toxins via marine food webs, and the mechanisms of toxicity, are still unknown. Therefore, we examined the toxic effects of a strain of K. mikimotoi (isolated from the South China Sea) on the proliferation and morphology of four mammalian cell lines (two normal cell lines and two cancer cell lines). In addition, we carried out a preliminary investigation on the mechanism of toxicity of the alga. The results show that the polar lipid-soluble component of K. mikimotoi significantly inhibited proliferation of the four cell lines, and resulted in the cells becoming spherical, swollen and damaged. The result of Annexin V and PI double-staining confirmed that cell membranes were disrupted. The malonaldehyde (MDA) contents in the medium of the four cell lines treated with the polar-lipid extracts all increased significantly, which indicates that the polar-lipid toxins produced by K. mikimotoi could adversely affect mammalian cells by inducing lipid peroxidation. We conclude that K. mikimotoi is a potential threat to human health, and the comprehensive effect of this dinoflagellate and its mechanisms should be investigated further.     

地热形成条件探索与找热方法研究

储、盖、通、源是对地热形成条件的简述。通过多年的地热勘查工作实践,笔者认为：储、盖、通、源仅仅是地热形成的必要条件,深部“承压水滞留”才是地热形成的充分条件。“储、盖、通、源、滞”是地热形成的“充要”条件。     

浅议空间信息网格

网格是科学家针对当今的一些科学难题于20世纪90年代初提出的新概念。它将分布在不同地理位置的计算资源包括CPU、存储器、数据库等,通过高速的互联网组成充分共享的资源集成,从而提供一种高性能计算、管理及服务的资源能力。在不久的将来很可能像今天的Internet一样占据人们的生活,而成为继Internet和Web之后正在到来的第三大浪潮。据统计,与空间位置有关的空间信息在信息总量中约占80％,社会发展和国民经济的持续增长必然对空间信息资源有空前巨大的需求。网格技术为空间信息获取与处理提供了新的技术途径,在空间信息科学领域具有非常广阔的应用前景。