Characterization and immunomodulatory activities of sulfated polysaccharides from Capsosiphon fulvescens

Sulfated polysaccharides isolated from Capsosiphon fulvescens and fractionated using ion-exchange chromatography were investigated to determine their chemical and molecular characteristics and biological activities. The crude and fractionated polysaccharides (F(1), F(2), and F(3)) consisted mostly of carbohydrates (28.9-67.0%), uronic acids (1.6-9.2%) and sulfates (5.2-13.4%) with various amounts of proteins (2.1-53.7%). Their monosaccharide levels were significantly different including rhamnose (20.8-65.2%), xylose (13.0-37.1%) and mannose (11.6-65.1%). The polysaccharides contained one or two subfractions with molecular weights (M(w)) ranging from 401.7×10(3) to 6232×10(3)g/mol. These polysaccharides (the crude and fraction F(2)) strongly stimulated macrophage cells, RAW264.7 cell line, producing considerable amounts of NO, PGE(2) and cytokines which suggested that they could be strong immunostimulators. The main backbone of the most immunoenhancing polysaccharide (F(2)) was suggested by GC-MS and NMR to be the following:     

Volatile substances of the green alga Scenedesmus incrassatulus

Volatile substances of the green microalga Scenedesmus incrassatulus, cultivated in fresh and salt water, were studied. Cultivation in fresh water diversifies volatile secondary metabolites. Hydrocarbons and derivatives of the acetate pathway predominate when algae are grown in salt water; isoprenoids and aromatics are more abundant after fresh water cultivation.     

A polysaccharide of the marine alga Capsosiphon fulvescens induces apoptosis in AGS gastric cancer cells via an IGF-IR-mediated PI3K/Akt pathway

Because seaweed extracts have recently been found to have antioxidant and anti-tumor activities, we analyzed a hot-water-soluble polysaccharide (PS) of the marine alga Capsosiphon fulvescens for its potential as a functional foodstuff by determining its effects on cell growth and DNA synthesis. MTS assays showed that the C. fulvescens PS (Cf-PS) significantly inhibited the proliferation of cultured human cancer cells in a dose-dependent manner. Cf-PS-treated AGS cells exhibited a marked increase in caspase-3 activation and a decrease in Bcl-2 expression. In addition, phosphorylation of insulin-like growth factor-I receptor (IGF-IR) was decreased in Cf-PS-treated AGS cells as compared to non-treated control cells, which is consistent with PI3-kinase (PI3K)/Akt activation. Cf-PS also decreased IGF-I-stimulated recruitment of p85 to IGF-IR and IRS-1. These results indicate that Cf-PS inhibits cell proliferation and induces apoptosis by inhibiting IGF-IR signaling and the PI3K/Akt pathway.     

Flip‐flop organization in the chloroplast genome of Capsosiphon fulvescens (Ulvophyceae,Chlorophyta)

To better understand organelle genome evolution of the ulvophycean green alga Capsosiphon fulvescens, we sequenced and characterized its complete chloroplast genome. The circular chloroplast genome was 111,561 bp in length with 31.3% GC content that contained 108 genes including 77 protein‐coding genes, two copies of rRNA operons, and 27 tRNAs. In this analysis, we found the two types of isoform, called heteroplasmy, were likely caused by a flip‐flop organization. The flip‐flop mechanism may have caused structural variation and gene conversion in the chloroplast genome of C. fulvescens. In a phylogenetic analysis based on all available ulvophycean chloroplast genome data, including a new C. fulvescens genome, we found three major conflicting signals for C. fulvescens and its sister taxon Pseudoneochloris marina within 70 individual genes: (i) monophyly with Ulotrichales, (ii) monophyly with Ulvales, and (iii) monophyly with the clade of Ulotrichales and Ulvales. Although the 70‐gene concatenated phylogeny supported monophyly with Ulvales for both species, these complex phylogenetic signals of individual genes need further investigations using a data‐rich approach (i.e., organelle genome data) from broader taxon sampling.     

Variation in the chemical composition of Capsosiphon fulvescens with area and during the harvest period

In this study, variations in Capsosiphon fulvescens composition with area and during the harvest period were assessed by analysis of crude protein, ash, and carbohydrate content. C. fulvescens in Janghung showed the highest crude protein content in December and the highest carbohydrate content in February. Changes in total amino acid, free amino acid, and fatty acid content were observed between December and February. Total amino-acid content of Janghung samples tended to decrease over the course of the harvest period, from 35.7?±?0.2?g 100?g^?1 in December to 32.9?±?0.2?g 100?g^?1 in February. Total amino-acid content in Janghung and Gohung samples was higher than that in Wando, except for glutamic acid. Significant increases in the major fatty acids (C12:0, C14:1 n-5, C18:0, C18:1 n-9, C18:2 n-6, C18:3 n-3, C20:0, C20:1 n-9, C22:1 n-9, C22:6 n-3, and C24:1 n-9) in Janghung were observed as the harvest period progressed. Fructose was the most abundant and glucose the second most abundant in the monosaccharide composition profiles, while galactose, ribose, and lactose were present in low quantites and mannitol, fucose, and arabinose were not detected.     

Bioaccumulation and toxicity of selenium compounds in the green alga Scenedesmus quadricauda

Background  

Selenium is a trace element performing important biological functions in many organisms including humans. It usually affects organisms in a strictly dosage-dependent manner being essential at low and toxic at higher concentrations. The impact of selenium on mammalian and land plant cells has been quite extensively studied. Information about algal cells is rare despite of the fact that they could produce selenium enriched biomass for biotechnology purposes.     

Scale biogenesis in the green alga,Mesostigma viride

Summary The unicellular green algal flagellate,Mesostigma viride, is characterized by an extracellular matrix of multiple layers of scales. These scales are processed within the Golgi apparatus (GA). The GA consists of 11–13 closely stacked cisternae. The cis cisternae are highly fenestrated and grow via vesicles from adjacent transition ER. Medial-trans cisternae are plate-like with swollen peripheries. The calcified basket scales are produced in the peripheries of GA cisternae, usually first observable in the medial zone of the cisternal stack. Cisternal membrane closely conforms to the precise architecture of the developing scale. Antimonate labeling reveals that a population of smooth cytoplasmic vacuoles situated near the GA contains a store of calcium, perhaps used for scale processing. Vesicles carry calcium from these vacuoles to the cisternal loci where basket scale ontogenesis is occurring. The smaller scale types are produced within the central areas of the GA. A discussion concerning membrane flow through the GA is provided.     

Copper tolerance in the green alga, Chlorella vulgaris

Abstract. The effect of sub-lethal concentrations of copper upon tolerant and non-tolerant strains of Chlorella vulgaris was investigated. Copper concentrations of 0.2 and 0.4 mg dm⁻³ increased the lag phase of both strains, the effect being greater in the non-tolerant strain. No difference was observed in the toxicity of copper to the photosynthetic rates of the isolated chloroplasts of either strain. However, significant differences were shown at the whole cell level.
Lower copper uptake was shown by the tolerant cells. In both strains initial uptake of copper was followed by a phase of desorption before cell division occurred. In cultures of both strains the concentration of ionic copper was decreased by complexation with extracellular organic material. Over a 14 day growth period more organic material was produced by the tolerant cells. The organic material produced by the tolerant cell formed organo-copper complexes which had a higher conditional stability constant.
It is proposed that the cell wall acts as a barrier to copper in the tolerant cells and prevents copper from affecting cell metabolism. Organo-copper complexation occurs at this barrier and this complex is then released into the medium.     

Cytochrome components of green alga, Bryopsis maxima

Five soluble cytochromes were isolated and were partially purifiedfrom Bryopsis maxima: Cytochrome b-562 is slightly autoxidizable and has a midpointredox potential of +175 mV at pH 7.0. Its molecular weight isclose to 30,000 as estimated by dextran gel filtration. Cytochrome b-555 is autoxidizable and can be reduced by dithionitebut not by ascorbate. Cytochrome c-549 is a basic protein. It is slightly autoxidizableand reducible with either ascorbate or dithionite. Cytochrome c-549_(LP) is autoxidizable and reducible with dithionitebut not with ascorbate. The reduced cytochrome combines withcarbon monoxide. Cytochrome c-553 is the f-type one, which was reported by Sugimuraet al. (1968). ¹ This paper is dedicated to the memory of the late Prof. AtusiTakamiya at Toho University. (Received September 10, 1976; )     

Assessment of the nutritional value of Capsosiphon fulvescens (Chlorophyta): developing a new species of marine macroalgae for cultivation in Korea

The nutritive value of Capsosiphon fulvescens (C. Agardh) Setchell et Gardner, a new developing species for cultivation of marine macroalgae in Korea, was assessed by comparison with common edible green seaweed Ulva prolifera (Oeder) J. Agardh collected from Korea and Japan, based on analysis of its chemical composition. The contents of protein and of total, essential, and free amino acids of C. fulvescens were significantly higher than those of U. prolifera, whereas those of lipid, carbohydrate, and total dietary fibres were significantly lower. There were no significant differences in the moisture content between Capsosiphon and Ulva species. The main minerals of Capsosiphon and Ulva are Na, Mg, K, Ca, and Al, making up approximately 97–99 % of the total minerals. The contents of Na and V of Capsosiphon were significantly greater than those of Ulva, while those of Mn and Sr were significantly lower in Capsosiphon. The contents of retinal (27.8 μg g⁻¹ dry wt) and ascorbic acid (0.28 mg g⁻¹ dry wt) of Capsosiphon were significantly higher than those of Ulva, but the contents of cobalamin were lower. These results suggest that C. fulvescens has greater potential to be used as human food and as an ingredient in formulated food.     

Cinnamic acid, coumarin and vanillin: Alternative phenolic compounds for efficient Agrobacterium-mediated transformation of the unicellular green alga, Nannochloropsis sp

The use of acetosyringone in Agrobacterium-mediated gene transfer into plant hosts has been favored for the past few decades. The influence of other phenolic compounds and their effectiveness in Agrobacterium-mediated plant transformation systems has been neglected. In this study, the efficacy of four phenolic compounds on Agrobacterium-mediated transformation of the unicellular green alga Nannochloropsis sp. (Strain UMT-M3) was assessed by using β-glucuronidase (GUS) assay. We found that cinnamic acid, vanillin and coumarin produced higher percentages of GUS positive cells as compared to acetosyringone. These results also show that the presence of methoxy group in the phenolic compounds may not be necessary for Agrobacterium vir gene induction and receptor binding as suggested by previous studies. These findings provide possible alternative Agrobacterium vir gene inducers that are more potent as compared to the commonly used acetosyringone in achieving high efficiency of Agrobacterium-mediated transformation in microalgae and possibly for other plants.     

Sulfated Glucuronorhamnoxylan from Capsosiphon fulvescens Ameliorates Osteoporotic Bone Resorption via Inhibition of Osteoclastic Cell Differentiation and Function In Vitro and In Vivo

Marine Biotechnology - Excessive osteoclast differentiation and/or bone resorptive function causes a gradual loss of bone, leading to the pathogenesis of bone diseases such as osteoporosis (OP). In...     

Phage-like infectious virus of the green alga Chlorococcum

A pure culture of the green eukaryotic alga Chlorococcum sp. and a virus infectious for it were isolated. Infection of the culture leads to the destruction of most of the cells, although complete destruction of the culture is not usually observed. The virus particles are similar in morphology to bacteriophage and consist of a hexagonal head 220 nm long and 180 nm wide and a tail which is inside the head in a majority of the particles, but which is on the outside in some. The virus is not adsorbed on the cell membranes, but evidently penetrates into the zoospores through the flagellar channels, where particles of it are regularly found. Destruction of the nucleus and membrane structures of the cytoplasm occurs during growth of the virus, but the chloroplasts and mitochondria are retained. The membranes of infected cells are partially destroyed and the virus particles are released into the medium. The virus is designated as PLVCH (L)--page-like virus of Chlorococcum.     

An anticoagulant proteoglycan from the marine green alga, Codium pugniformis

An anticoagulant isolated from the marine green alga Codium pugniformis was composed mainly of glucose with minor amounts of arabinose and galactose. It was highly sulfated (326 μg mg^-1 polysaccharide) and contained protein(52 μg mg^-1 polysaccharide) and was thus a proteoglycan. The anticoagulant properties of the purified proteoglycan were compared with those of heparin by studying the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time(TT) using normal human plasma. The proteoglycan showed similar activities to heparin, but was weaker than heparin. On the other hand, the proteoglycan did not affect PT even at the concentration at which APTT and TT were prolonged. The anticoagulation mechanism of this proteoglycan was due to the direct inhibition of thrombin and the potentiation of antithrombin III. This revised version was published online in August 2006 with corrections to the Cover Date.     

Signal transduction during fertilization in the unicellular green alga, Chlamydomonas

Sexual reproduction in the green alga, Chlamydomonas, is regulated by environmental conditions and by cell-cell interactions. After gametogenesis, flagellar adhesion between gametes triggers gamete activation, leading to cell fusion and zygote formation. Recent studies have identified new molecular events that underlie signal transduction during Chlamydomonas fertilization, including expression of a sex-determining protein, phosphorylation of a homeodomain protein, activity of a kinesin II and regulated translocation of an aurora/Ip11-like protein kinase from the cell body to the flagella.