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1.
Novel sulfated polysaccharide derived from red-tide microalga Gyrodinium
impudicum strain KG03 with immunostimulating activity in vivo 总被引:1,自引:0,他引:1
The high-sulfate-containing exopolysaccharide p-KG03 is produced by the red-tide microalga Gyrodinium impudicum strain KG03. The immunostimulatory effects of this sulfated exopolysaccharide were investigated by isolating peritoneal macrophages from mice 10 or 20 days after they had received a single dose of p-KG03 (100 or 200 mg/kg body weight). The cytotoxicity of the isolated macrophages for B16 tumor cells was tested, as B16 tumor cells are sensitive to tumor necrosis factor α (TNF-α) and nitric oxide. The activities of natural killer cells from the p-KG03-treated mice against YAC-1 mouse lymphoma cells were also tested. The nonspecific immune functions mediated by natural killer cells and macrophages were increased by treatment with p-KG03 in vivo. These results suggest that p-KG03 has immunostimulatory effects and enhances the tumoricidal activities of macrophages and NK cells in vivo. In addition, p-KG03 treatment increased the plaque-forming cell response to sheep red blood cells, as well as the levels of IgM and IgG Exposure to p-KG03 also increased the production by macrophages of cytokines, such as interleukins -1β and -6, and TNF-α. This is the first report of a marine microalgal sulfated polysaccharide having immunostimulatory activities. The p-KG03 polysaccharide may be useful for the development of biotechnological and pharmaceutical products that incorporate bioactive marine exopolysaccharides. 相似文献
2.
A marine microalga Gyrodinium impudicum strain KG03 produced sulfated exopolysaccharide designated as p-KG03, which showed a strong antiviral activity against encephalomyocarditis virus (EMCV). To optimize culture conditions for the production of p-KG03, mineral salts, vitamins, plant growth hormones, temperature, pH and light conditions were examined. From this study, M-KG03 medium for the maximum production of p-KG03 was suggested as follows; NH(4)Cl 75 microM, NaH(3)PO(4) 200 microM, NaHCO(3) 50 microM, Na(2)SO(4) 10 microM, FeCl(2) x 6H(2)O 10 microM, MnCl(2) x 4H(2)O 0.1 microM, vitamin B(12) 0.75 microg, naphthalene acetic acid (NAA) 7.5 microg and myo-inositol 200 mg per liter of aged sea water. The optimal temperature and pH were 22.5 degrees C and 8.0, respectively. The optimal light conditions of intensity and period were 150 microE m(-2) s(-1) and 16:8 h light:dark cycle. Finally, the cell growth and p-KG03 production were measured in one liter of M-KG03 medium with 1% CO(2) and 50 ml min(-1) of airflow using two liters airlift balloon type photobioreactor (ABTPR). At these optimal conditions, p-KG03 production and cell growth were 134.6+/-5.9 mg l(-1) and 123,076+/-1,597 cells ml(-1), respectively, representing a 7.7 and 5.1 times compared with f/2 medium with Erlenmeyer flask culture (p-KG03 production 17.5+/-1.3 mg l(-1) and cell growth 24,311+/-1,291 cells ml(-1)). 相似文献
3.
Characterization of a novel bioflocculant, p-KG03, from a marine dinoflagellate, Gyrodinium impudicum KG03 总被引:15,自引:0,他引:15
The flocculating activity of an exopolysaccharide, p-KG03, produced by a marine dinoflagellate Gyrodinium impudicum KG03 was investigated. The p-KG03 was a highly sulfated exopolysaccharide that showed strong antiviral activity against encephalomyocarditis virus (EMCV) and immunostimulating activity by NK cell activation. For the industrial applications of p-KG03, as the bioflocculant agent, p-KG03 showed that more than 90% of the flocculating activity in kaolin suspension occurred at concentrations of 0.5 mg/l with the maximum at 1.0 mg/l. However, flocculation decreased from 2.5 mg/l. The flocculation rate increased linearly with concentration and was higher than that observed in commercial products such as polyacrylamide (approximately 1.0 mg/l) or zooglan (approximately 3.0 mg/l). The p-KG03 was an effective flocculant under acidic conditions (pH 3-6) and over a wide temperature range (4-90 degrees C). The presence of cations did not enhance flocculating activity. The average molecular mass, as determined by gel filtration chromatography, was about 1.87 x 10(3) KDa. Galactose was the main sugar in p-KG03, which also contained uronic acid (2.9%, w/w) and sulfate groups (10.3%, w/w). The infrared spectrum of p-KG03 showed absorption bands of carboxylate groups. Thermogravimetric analysis indicated a degradation temperature (T(d)) of 250 degrees C. Several other properties of p-KG03 such as intrinsic viscosity, the rheological behavior, consistency index (k) and flow behavior index (eta) were also studied. 相似文献
4.
Satoru Kobayashi Natsuhiko Kojima Shigeru Itakura Ichirou Imai Kazumi Matsuoka 《Phycological Research》2001,49(1):61-65
Cysts of a chain‐forming dinoflagellate Gyrodinium impudicum Fraga et Bravo (Gymnodiniales) were found in surface sediments of Harima‐Nada and Nakaumi, western Japan. The detailed morphology of living and empty cysts is described. The living cysts are roundish to ellipsoidal in polar view, and hemispherical in lateral view. Among three empty cysts obtained, two different archeopyles were observed; either a long slit with an operculum, or a hole with irregular zigzag outline. The living cysts of Gyro. impudicum are morphologically similar to those of the genus Chattonella antiqua (Hada) Ono and Chattonella marina (Subrahmanyan) Y. Hara et Chihara (Raphidophyceae), except cyst color and contents. The living cysts of Gyro. impudicum were rarely encountered, and their density was always less than 1 cell in 1 cm?3 in the present samples. 相似文献
5.
Starvation-specific formation of a peripheral exopolysaccharide by a marine Pseudomonas sp., strain S9 总被引:1,自引:0,他引:1
M Wrangstadh U Szewzyk J Ostling S Kjelleberg 《Applied and environmental microbiology》1990,56(7):2065-2072
The marine bacterium Pseudomonas sp. strain S9 produces exopolysaccharides (EPS) during both growth and total energy source and nutrient starvation. Transmission electron microscopy of immunogold-labeled cells demonstrated that the EPS is closely associated with the cell surface during growth (integral EPS), while both the integral form and a loosely associated extracellular (peripheral) form were observed during starvation. Formation and release of the latter rendered the starvation medium viscous. In addition, after 3 h of starvation in static conditions, less than 5% of the cells were motile, compared with 100% at the onset of starvation and approximately 80% subsequent to release of the peripheral EPS at 27 h of starvation. Inhibition of protein synthesis with chloramphenicol added before 3 h of starvation caused no increase in viscosity. However, addition of chloramphenicol at 3 h did not prevent the subsequent increase in viscosity displayed by S9 cells. The amount of integral EPS increased for both nontreated and chloramphenicol-treated S9 cells during the first hour of starvation, with a subsequent equal decrease. The chloramphenicol-treated cells, as well as cells of a transposon-generated mutant strain deficient in peripheral EPS formation, remained adhesive to a hydrophobic inanimate surface during the initial 5 h of starvation, whereas nontreated wild-type cells had progressively decreased adhesion capacity. During the initial 5 h of starvation, most of the nontreated cells but only a small fraction of the chloramphenicol-treated and mutant cells detached from the hydrophobic substratum.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Tadashi Matsunaga Mitsufumi Matsumoto Yoshiaki Maeda Hiroshi Sugiyama Reiko Sato Tsuyoshi Tanaka 《Biotechnology letters》2009,31(9):1367-1372
A marine microalga, strain JPCC GA0024 was selected as high amount of neutral lipid producers from marine microalgal culture
collection toward biofuel production. The strain was tentatively identified as Scenedesmus
rubescens by 18S rDNA analysis. The growth of strain JPCC GA0024 was influenced by artificial seawater concentrations. The optimum
growth of 0.79 g/l was obtained at 100% artificial seawater. The lipid accumulation reached 73.0% of dry cell weight at 100%
artificial seawater without additional nutrients for 11 days. Gas chromatography/mass spectrometry analysis indicates that
lipid fraction mainly contained hydrocarbons including mainly hexadecane (C16 H34) and 1-docosene (C22 H44). Furthermore, calorimetric analysis revealed that the energy content of strain JPCC GA0024 was 6,160 kcal/kg (25.8 MJ/kg)
of calorific value, which was equivalent to the coal engery. The strain JPCC GA0024, S.
rubescens, will become a promising resource that can grow as a dominant species in the seawater for the production of both liquid and
solid biofuels. 相似文献
8.
A bacterial strain NF3 was isolated from a sludge sample from Inlet Admiralty Bay (Antarctica) and has been identified as belonging to the genus Alteromonas. The isolate was a Gram-negative rod with a single polar flagellum arrangement. The strain was catalase and oxidase positive and capable of gelatin hydrolysis. The G + C content was 42 mol%. The fatty acid composition and the protein profile has confirmed its identification as Alteromonas sp. During cell growth, the strain produced an exopolymer composed of 76–86% protein and 8–14% sugars depending on the medium used. 相似文献
9.
Starvation-specific formation of a peripheral exopolysaccharide by a marine Pseudomonas sp., strain S9. 总被引:2,自引:2,他引:0 下载免费PDF全文
The marine bacterium Pseudomonas sp. strain S9 produces exopolysaccharides (EPS) during both growth and total energy source and nutrient starvation. Transmission electron microscopy of immunogold-labeled cells demonstrated that the EPS is closely associated with the cell surface during growth (integral EPS), while both the integral form and a loosely associated extracellular (peripheral) form were observed during starvation. Formation and release of the latter rendered the starvation medium viscous. In addition, after 3 h of starvation in static conditions, less than 5% of the cells were motile, compared with 100% at the onset of starvation and approximately 80% subsequent to release of the peripheral EPS at 27 h of starvation. Inhibition of protein synthesis with chloramphenicol added before 3 h of starvation caused no increase in viscosity. However, addition of chloramphenicol at 3 h did not prevent the subsequent increase in viscosity displayed by S9 cells. The amount of integral EPS increased for both nontreated and chloramphenicol-treated S9 cells during the first hour of starvation, with a subsequent equal decrease. The chloramphenicol-treated cells, as well as cells of a transposon-generated mutant strain deficient in peripheral EPS formation, remained adhesive to a hydrophobic inanimate surface during the initial 5 h of starvation, whereas nontreated wild-type cells had progressively decreased adhesion capacity. During the initial 5 h of starvation, most of the nontreated cells but only a small fraction of the chloramphenicol-treated and mutant cells detached from the hydrophobic substratum.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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《Enzyme and microbial technology》2006,38(1-2):220-222
Exopolysaccharide produced by a marine Enterobacter cloaceae (designated as EPS 71a) emulsified hexane, benzene, xylene, kerosene, paraffin oil, cottonseed oil, coconut oil, jojoba oil, castor oil, groundnut oil and sunflower oil. However, it could form stable emulsions with groundnut oil and hexane at optimal concentration of 1 mg ml−1. Further increase in concentration of EPS 71a did not show noteworthy increase in emulsification indices. Emulsions with groundnut oil and hexane were stable up to 10 days between pH 2 and 10 and in the presence of sodium chloride in the range of 5–50 mg ml−1 at 35–37 °C. EPS 71a formed stable emulsion with xylene as compared to commercial gums such as arabic, tragacanth, karaya and xanthan. 相似文献
13.
The cryopreservation of algae could prevent genetic drift and minimize labor costs compared to the current method of maintenance and subculturing. Clear, simple protocols for cryopreservation of marine microalga, Nannochloropsis oculata were developed and cryoprotectant choice and concentration optimized. The viability of the microalga was assessed directly after thawing, and algal concentration was measured after 2-30 days of growth. Five cryoprotectants (dimethyl sulphoxide, Me2SO; ethylene glycol, EG; glycerol, Gly; methanol, MeOH; and propylene glycol, PG) at five concentrations (10, 20, 30, 40, and 50%; v/v) were evaluated to determine the toxicity of various cryoprotectants to N. oculata. The toxicity of cryoprotectant (Me2SO, EG, MeOH, and PG) was observed only at higher concentrations of CPAs: > 20% for EG, > 30% for Me2SO and methanol, and > 40% for PG. Direct freezing of algae in liquid nitrogen resulted in a severe loss of viability and a modified cryopreservation protocol proved to be more appropriate for the preservation of N. oculata. Cryopreservation protocols developed and tested in the present study might be applied to cryopreserving other strains, or species, in this genus. 相似文献
14.
Stéphanie Godet Josiane Hérault Gaëlle Pencreac’h Françoise Ergan Céline Loiseau 《Journal of applied phycology》2012,24(6):1547-1553
Microalgae constitute a novel study area for characterising new lipolytic enzymes of biotechnological interest. A new gene from the microalga Isochrysis galbana has been isolated and a preliminary characterisation performed. The full-length cDNA contains 2,060 base pairs with an open reading frame of 1,374 nucleotides encoding a polypeptide of 457 amino acids with a predicted molecular mass of 49 kDa, and a theoretical pI of 5.65. The deduced protein includes highly conserved motifs found in α/β fold hydrolases, and shares some similarities with putative or known lipases. Sequence comparison indicated that the catalytic triad corresponds to residues Ser188, Asp306 and His391, with the nucleophilic residue Ser188 positioned within the consensus G-X-S188-X-G pentapeptide. Phylogenetic analyses established close relationships with fungal lipases and microalgal sequences. 相似文献
15.
A. Mejia Alvarez A. Gelista B. V. Resendiz F. N. Rodriguez 《Biotechnology letters》1990,12(4):283-288
Sumary A mutant strain, derived fromNocardia
mediterranei ATCC 13685 was found to accumulate rifamycin B in shake flask as major product, but the same strain in a 500-liter fermenter, produces a mixture of rifamycin B and other ansamycin, which was identificated by C NMR as rifamycin W. 相似文献
16.
Inmaculada Llamas Ana del Moral Victoria Béjar Mara Dolores Girón Rafael Salto Emilia Quesada 《FEMS microbiology letters》1997,156(2):251-257
The moderately halophilic bacterium Halomonas eurihalina strain F2-7, able to produce an exopolysaccharide, was found to contain two plasmids named pVE1 and pVE2, of 8.1 and 5.8 kb respectively. We found no evidence for the involvement of these plasmids in the expression of the mucoid phenotype. Restriction maps of both plasmids were constructed. Southern hybridization revealed similarities between them but excluded the existence of sequences homologous to other plasmids isolated from the Halomonas species. Neither pVE1 nor pVE2 displayed any homology with other plasmids isolated from moderate halophiles. The occurrence of similar plasmids in other strains of Halomonas eurihalina, isolated from hypersaline soils, has been detected. These small plasmids may be useful for the development of cloning vectors for moderately halophilic bacteria. 相似文献
17.
A crtD (1-HO carotenoid 3,4-dehydrogenase gene) homolog from marine bacterium strain P99-3 included in the gene cluster for the biosynthesis of myxol (3′,4′-didehydro-1′,2′-dihydro-β,ψ-carotene-3,1′,2′-triol) was functionally identified. The P99-3 CrtD was phylogenetically distant from the other CrtDs. A catalytic feature was its high activity for the monocyclic carotenoid conversion: 1′-HO-torulene (3′,4′-didehydro-1′,2′-dihydro-β,ψ-caroten-1′-ol) was prominently formed from 1′-HO-γ-carotene (1′,2′-dihydro-β,ψ-caroten-1′-ol) in Escherichia coli with P99-3 CrtD, indicating that this enzyme has been highly adapted to myxol biosynthesis. This unique type of crtD is a valuable tool for obtaining 1′-HO-3′,4′-didehydro monocyclic carotenoids in a heterologous carotenoid production system. 相似文献
18.
Antiviral Effects of Sulfated Exopolysaccharide from the Marine Microalga <Emphasis Type="Italic">Gyrodinium impudicum</Emphasis> Strain KG03 总被引:5,自引:0,他引:5
The sulfated exopolysaccharide p-KG03, which is produced by the marine microalga Gyrodinium impudicum strain KG03, exhibited impressive antiviral activity in vitro (EC50 = 26.9 µg/ml) against the encephalomyocarditis virus (EMCV). Depending on the p-KG03 concentration, the development of cytopathic effects in EMCV-infected HeLa cells was either inhibited completely or slowed. Moreover, p-KG03 did not show any cytotoxic effects on HeLa cells, even at concentrations up to 1000 µg/ml. The polysaccharide was purified by repeated precipitation in ethanol, followed by gel filtration. The p-KG03 polysaccharide had a molecular weight of 1.87 × 107, and was characterized as a homopolysaccharide of galactose with uronic acid (2.96% wt/wt) and sulfate groups (10.32% wt/wt). The biological activities of p-KG03 suggest that sulfated metabolites from marine organisms are a rich source of antiviral agents. This is the first reported marine source of antiviral sulfated polysaccharides against EMCV. The p-KG03 polysaccharide may be useful in the development of marine bioactive exopolysaccharide for biotechnological and pharmaceutical products. 相似文献
19.
Influence of culture conditions on exopolysaccharide production by Lactobacillus rhamnosus strain C83 总被引:5,自引:1,他引:5
The influence of culture conditions on growth and exopolysaccharide (EPS) production by Lactobacillus rhamnosus strain C83 was investigated using fermentor batch cultures. A temperature shift (from 37 to 25 °C) at the beginning of the exponential growth phase (0–5 h) enhanced EPS production. Furthermore, an optimal environmental pH of 6·2–7·2 improved the performance of strain C83 and partially anaerobic culture conditions (pO2 from 0 to 10%) triggered EPS over-production by the cells. The sugar composition of this polymer was independent of culture conditions, such as carbon source, medium composition, temperature, pH, pO2 and growth phases. In all cases, galactose and glucose were the principal components. 相似文献
20.
An exopolysaccharide producing marine bacterium, Enterobacter cloacae, was isolated from marine sediment collected from Gujarat coast, India. Chemical investigation of exopolysaccharide (EPS 71 a) revealed that this exopolysaccharide was an acidic polysaccliaride containing high amount of uronic acid, fucose and sulfate which is rare for bacterial exopolysaccharides. EPS 71a was found to have fucose, galactose, glucose and glucuronic acid in a molar ratio of 2: 1: 1: 1. 相似文献