In vitro assembly of R-phycoerythrin from marine red alga Polysiphonia urceolata

Scanning tunneling microscope was used to investigate the in vitro assembly of R-phycoerythrin (R-PE) from the marine red alga Polysiphonia urceolata. The results showed that R-PE molecules assembled together by disc-to-disc while absorbing on HOPG surface, which just looked like the rods in the phycobilisomes. When the water-soluble R-PE was dissolved in 2% ethanol/water spreading solution, they could form monolayer film at the air/water interface. Similar disc-to-disc array of R-PE was constituted in the two-dimensional Langmuir-Blodgett film by the external force. It could be concluded that, apart from the key role of time linker polypeptides, the in vivo assembly of phycobiliproteins into phycobilisomes is also dependent on the endogenous properties of phycobiliprotein themselves.

Characteristics and comparative study of chlorophyll-protein complexes from siphonous green algae

By mild PAGE method, 11, 11, 7 and 9 chlorophyll-protein complexes were isolated from two species of siphonous green algae ( Codium fragile (Sur.) Harlot and Bryopsis corticulans Setch.), green alga (Ulothrix flacca (Dillw.) Thur.), and spinach (Spinacia oleracea Mill.), respectively. Apparent molecular weights, Chi a/b ratios, distribution of chlorophyll, absorption spectra, low temperature fluorescence spectra of these complexes were determined, and compared with one another. PS I complexes of two siphonous green algae are larger in apparent molecular weight because of the attachment of relative highly aggregated LHC I. Four isolated light-harvesting complexes of PSII are all siphonaxanthin-Chl a/b-protein complexes, and they are not monomers and oligomers like those in higher plants. Especially, the absence of 730 nn fluorescence in PS I complexes indicates a distinct structure and energy transfer pattern.

Preparation of chloroplasts from brown algae

Thalli from a brown alga Undaria pinnatifida were soaked by CaCl2 solution with different concentration and time at 4 degreesC, the effect of CaCl2 solution on efficiency and influorescence emission spectra of chloroplasts were examined. The results show that the efficiency of collected chloroplasts is increased markedly after soaking in CaCl2 solution. According to the results of collected efficiency and characteristic of influorescence emission spectra at room temperature of chloroplasts, it was suggested that soaking in the 0.2 mol/L CaCl2 solution for 10 min is optimum. Under this condition, the efficiency of collected chloroplasts is as 5 fold as control group, and the characteristics of chloroplasts obtained by CaCl2 soaking are similar to that of traditional method.

Study on the concentration and seasonal variation of inorganic elements in 35 species of marine algae

The concentrations of five major and 28 trace elements in 35 marine algae collected along the coast of China were determined by instrumental neutron activation analysis. The concentrations of halogens, rare earth elements and many transition metal elements in marine algae are remarkably higher than those in terrestrial plants. The concentration factors for 31 elements in all collected algae were calculated, those for tri- and tetra-valent elements were higher than those of the mono- and di-valent elements in marine algae. The biogeochemical characteristics of inorganic elements in marine algae were investigated. In addition, the seasonal variation of inorganic elements in Sargassum kjellmanianum was also studied. (C) 1998 Elsevier Science B.V. All rights reserved.

Seeding nets with neutral spores of the red alga Porphyra umbilicalis (L.) Kutzing for use in integrated multi-trophic aquaculture (IMTA)

Nets in traditional Porphyra mariculture are seeded with conchospores derived from the conchocelis phase, and spend a nursery period in culture tanks or calm coastal waters until they reach several centimeters in length. Some species of Porphyra can regenerate the foliose phase directly through asexual reproduction, which suggests that the time, infrastructure, and costs associated with conchocelis culture might be avoided by seeding nets with asexual spores. Here, we present work from a short-term mariculture study using nets seeded with asexual spores (neutral spores) of a native Maine species of Porphyra. Porphyra umbilicalis (L.) Kutzing was selected for this proof of concept research because of its reproductive biology, abundance across seasons in Maine, and evidence of its promise as a mariculture crop. We studied the maturation, release, and germination of the neutral spores to develop an appropriate seeding protocol for nets, followed by development of a nursery raceway to provide an easily manipulated environment for the seeded nets. Neutral spores were produced throughout the year on the central Maine coast,however, there was a temporal variability in the number and survival of released neutral spores, depending upon thallus position in the intertidal zone. Small thalli were strictly vegetative, but most thalli reproduced by neutral spores- sexual reproduction was absent. Neutral spores germinated quickly at 10 and 15 'C, but germination was delayed at 5 degrees C. Unlike some algal zygotes and spores, neutral spores of R umbilicalis required light to germinate; however, irradiances of 25 and 100 mu mol photons M-2 S-1 were equally sufficient for germination. Rafts of seeded nets were deployed in Cobscook Bay, Maine, at two distances from salmon aquaculture pens and at a control site on a nearby, fallow aquaculture site (no salmon). There was no difference in nitrogen content of harvested thalli; however, both the density and the surface area of harvested thalli were different among the sites. The possible causes of these differences are discussed in the context of potential use of P umbilicalis in IMTA. (C) 2007 Elsevier B.V. All rights reserved.

Isolation, antimicrobial activity, and metabolites of fungus Cladosporium sp associated with red alga Porphyra yezoensis

Cladosporium sp. isolate N5 was isolated as a dominant fungus from the healthy conchocelis of Porphyra yezoensis. In the re-infection test, it did not cause any pathogenic symptoms in the alga. Twenty-one cultural conditions were chosen to test its antimicrobial activity in order to obtain the best condition for large-scale fermentation. Phenylacetic acid, p-hydroxyphenylethyl alcohol, and L-beta-phenyllactic acid were isolated from the crude extract as strong antimicrobial compounds and they are the first reported secondary metabolites for the genus Cladosporium. In addition, the Cladosporium sp. produced the reported Porphyra yezoensis growth regulators phenylacetic acid and p-hydroxyphenylacetic acid. No cytotoxicity was found in the brine shrimp lethality test, which indicated that the environmental-friendly Cladosporium sp. could be used as a potential biocontrol agent to protect the alga from pathogens.

Natural bromophenols from the marine red alga Polysiphonia urceolata (Rhodomelaceae): Structural elucidation and DPPH radical-scavenging activity

Three new natural occurring bromophenols, 3-(3-bromo-4,5-dihydroxyphenyl)-2-(3,5-dibromo-4-hydroxyphenyl)propionic acid (1), (E)-4-(3-bromo-4,5-dihydroxyphenyl)-but-3-en-2-one (2), and (3,5-dibromo-4-hydroxyphenyl) acetic acid butyl ester (3), together with one known bromophenol, 1,2-bis(3-bromo-4,5-dihydroxyphenyl)ethane (4), were isolated and identified from the marine red alga Polysiphonia urceolata. The structures of these compounds were elucidated by extensive analysis of ID and 2D NMR and IR spectra and MS data. Each of the isolated compounds was evaluated for scavenging alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical activity and all of them exhibited significant activity with IC50 values ranging from 9.67 to 21.90 mu M, compared to the positive control, a well-known antioxidant butylated hydroxytoluene (BHT), with IC50 83.84 mu M. (C) 2007 Elsevier Ltd. All rights reserved.

Comparative analysis of astaxanthin and its esters in the mutant E1 of Haematococcus pluvialis and other green algae by HPLC with a C30 column

A gradient reversed-phase high-performance liquid chromatography (HPLC) method using a C30 column was developed for the simultaneous determination of astaxanthin, astaxanthin monoesters and astaxanthin diesters in the green algae Chlorococcum sp., Chlorella zofingiensis, Haematococcus pluvialis and the mutant E1, which was obtained from the mutagenesis of H. pluvialis by exposure to UV-irradiation and ethyl methanesulphonate (EMS) with subsequent screening using nicotine. The results showed that the contents of total astaxanthins including free astaxanthin and astaxanthin esters ranged from 1.4 to 30.9 mg/g dry biomass in these green algae. The lower total astaxanthin levels (< 2 mg/g dry biomass) were detected in the green algae Chlorococcum sp. and C. zofingiensis. The higher total astaxanthin levels (> 16 mg/g dry biomass) were found in the green alga H. pluvialis and its mutant E1. It is notable that the mutant E1 is found to have considerably higher amounts of total astaxanthin (30.9 mg/g) as compared to the wild strain of H. pluvialis (16.1 mg/g). This indicates that UV-irradiation and EMS compound mutagenesis with subsequent screening using nicotine is an effective method for breeding of a high-producing astaxanthin strain of H. pluvialis. In addition, the green alga C. zofingiensis had a remarkably higher percentage of astaxanthin diesters (76.3% of total astaxanthins) and a remarkably lower percentage of astaxanthin monoesters (18.0% of total astaxanthins) in comparison with H. pluvialis (35.5% for diesters and 60.9% for monoesters), the mutant E1 (49.1% and 48.1%) and Chlorococcum sp. (18.0% and 58.6%).

Evaluation of 28 marine algae from the Qingdao coast for antioxidative capacity and determination of antioxidant efficiency and total phenolic content of fractions and subfractions derived from Symphyocladia latiuscula (Rhodomelaceae)

The extracts obtained from 28 species of marine algae were evaluated for their antioxidant activity (AA) versus the positive controls butylated hydroxytoluene (BHT), gallic acid (GA), and ascorbic acid (AscA). Most of the tested samples displayed antioxidant activity to various degrees. Among them, the extract of Symphyocladia latiuscula exhibited the strongest AA, which was comparable to BHT, GA, and AscA in radical scavenging activity, as shown in the DPPH (alpha,alpha-diphenyl-beta-picrylhydrazyl) assay, and higher than those of the positive controls in beta-carotene-linoleate assay system. In addition, the ethyl acetate-soluble fraction isolated from the crude extract of S. latiuscula exhibited the highest antioxidant activity in both assay systems. This fraction was further fractionated into seven subfractions (F1-F7) by vacuum liquid chromatography (VLC). F1 and F4 were found to be the most effective subfractions in scavenging DPPH radical assay and in the beta-carotene-linoleate assay, respectively. The total phenolic content (TPC) and reducing power (RP) for all of the extracts, fractions, and subfractions (F1-F7) were also determined. The TPC of the 28 extracts ranged from 0.10 to 8.00 gallic acid equivalents (mg/g seaweed dry weight) while the RP ranged from 0.07 to 11.60 ascorbic acid equivalents (mg center dot g(-1) seaweed dry weight). Highly positive relationships between AA and TPC as well as between AA and RP were found for the extracts and fractions, while for the subfractions F1-F7 only weak or no such relations were found. The results obtained from this study indicate that further analysis is needed of those marine algal species that contain the most antioxidant activity in order to identify the active principles.

Species identification in salted products of red snappers by semi-nested PCR-RFLP based on the mitochondria 12S rRNA gene sequence

A molecular approach was developed to distinguish species of red snappers among commercial salted fish products. The specific fragments of the mitocliondrial 12S rRNA gene, which were about 450 bp, were obtained using the semi-nested polymerase chain reaction (semi-nested PCR). Subsequently, PCR amplicons were sequenced, aiming to select restriction endonucleases that generated species-specific restriction fragment length polymorphism (RFLP) profiles. Discrimination of red snappers Lutjanus sanguineus, L. erythopterus from L. argentintaculatus, L. malabarius and other morphologically similar fishes such as Lethrinus leutjanus and Pinjalo pinjalo was feasible by one restriction digestion reaction with three endonucleases Hae III, Sca I and SnaB I, however, for differentiation of L. sattguineus and L. erythopterus, another restriction digestion reaction with single restriction endonuclease Mae II was needed. The seminested PCR-RFLP was demonstrated to be reliable in species identification of salted fish products in this study. (c) 2005 Published by Elsevier Ltd.

Evaluation of antioxidant property of extract and fractions obtained from a red alga, Polysiphonia urceolata

Antioxidant activity (AA), total phenolic content, and reducing power of the crude extract, fractions, and subfractions derived from a red alga, Polysiphonia urceolata, were evaluated and determined. The antioxidative activity was measured using the alpha,alpha-diphenyl-beta-pierylhydrazyl (DPPH) radical scavenging assay and the P-carotene-linoleate assay systems, and compared with that of butylated hydroxytoluene (BHT), gallic acid (GA), and ascorbic acid (AscA). The results showed that the crude extract and the ethyl acetate-soluble fraction exhibited higher AA than BHT in the DPPH assay model, at all of four concentration levels tested (from 0.4 to 50 mu g/ml), while, in the beta-carotene-linoleate assay system, the crude extract and the ethyl acetate-soluble fraction exhibited similar or, in most cases, higher AA than GA and AscA at the same concentrations (from 10 to 200 mu g/ml). The ethyl acetate-soluble fraction was further fractionated into seven subfractions F1-F7 by silica gel vacuum liquid chromatography. F1 was found to be the most effective subfraction in both assay systems. The total phenolic content and reducing power were determined using the Folin-Ciocalteu and the potassium ferricyanide reduction methods, respectively. Statistical analysis indicated a significant association between the antioxidant potency and total phenolic content as well as between the antioxidant potency and reducing power. (c) 2005 Elsevier Ltd. All rights reserved.

Isolation and characterization of the oxygen-evolving photosystem II complex from the economical red alga Bangia fusco-purpurea

The highly pure and active photosystem II (PSII) complex was isolated from Bangia fusco-purpurea (Dillw) Lyngb., an important economic red alga in China, through two steps of sucrose density gradient ultracentrifugation and characterized by the room absorption and fluorescence emission spectra, DCIP (2,6-dichloroindophenol) reduction, and oxygen evolution rates. The PSII complex from B. fusco-purpurea had the characteristic absorption peaks of chlorophyll (Chl) a (436 and 676 nm) and typical fluorescence emission peak at 685 nm (Ex = 436 nm). Moreover, the acquired PSII complex displayed high oxygen evolution (139 mu mol O-2/(mg Chl h) in the presence of 2.5 mM 2,6-dimethybenzoqinone as an artificial acceptor and was active in photoreduction of DCIP (2,6-dichloroindophenol) by DPC (1,5-diphenylcarbazide) at 163 U/(mg Chl a h). SDS-PAGE also suggested that the purified PSII complex contained four intrinsic proteins (D1, D2, CP43, and CP47) and four extrinsic proteins (33-kD protein, 20-kD protein, cyt c-550, and 14-kD protein).

Laurenidificin, a new brominated C-15-acetogenin from the marine red alga Laurencia nidifica

new brominated C-15-acetogenin, namely, laurenidificin, was isolated from the marine red alga Laurencia nidifica. Its structure was determined on the basis of spectroscopic methods. (C) 2010 Bin Gui Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.