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1

Green Algae  

NSDL National Science Digital Library

Color photomicrographs of several species of green algae with brief descriptions of their chief characteristics and habitat. Scroll to the bottom of the page to links to bacteria, and more protists including diatoms, desmids and rotifers.

Van Egmond, Wim

2010-01-01

2

The lipid composition of the unicellular green alga Chlamydomonas reinhardtii and the diatom Cyclotella meneghiniana investigated by MALDI-TOF MS and TLC  

Microsoft Academic Search

The lipid composition of algae is crucial for numerous structural and physiological aspects, e.g. the integrity of the photosynthetic complexes and the functionality of membrane-embedded processes as the photosynthetic electron transport in thylakoids or the mitochondrial respiration. In this paper the lipid composition of the organic extracts of the green alga Chlamydomonas reinhardtii and the diatom Cyclotella meneghiniana are compared

Astrid Vieler; Christian Wilhelm; Reimund Goss; Rosmarie Süß; Jürgen Schiller

2007-01-01

3

A comparison of the character of algal extracellular versus cellular organic matter produced by cyanobacterium, diatom and green alga.  

PubMed

This study investigated characteristics of algal organic matter (AOM) derived from three species (cyanobacterium Microcystis aeruginosa, diatom Fragilaria crotonensis and green alga Chlamydomonas geitleri) which dominate phytoplanktonic populations in reservoirs supplying drinking water treatment plants. Algal growth was monitored by cell counting, optical density and dissolved organic carbon concentration measurements. Extracellular organic matter (EOM) released at exponential and stationary growth phases and cellular organic matter (COM) were characterised in terms of specific UV absorbance (SUVA), peptide/protein and non-peptide content, hydrophobicity and molecular weight (MW). It was found that both EOM and COM were predominantly hydrophilic with low SUVA. COM was richer in peptides/proteins, more hydrophilic (with about 89% of hydrophilic fraction for all three species) and had lower SUVA than EOM. MW fractionation showed that both EOM and COM of all three species contain large portions of low-MW (<1 kDa) compounds and high-MW (>100 kDa) polysaccharides. Peptides/proteins exhibited narrower MW distribution than non-peptide fraction and it widened as the cultures grew. The highest amount of peptides/proteins with a significant portion of high-MW ones (22%) was observed in COM of M. aeruginosa. The results imply that the knowledge of AOM composition and characteristics predetermine which processes would be effective in the treatment of AOM laden water. PMID:24388829

Pivokonsky, Martin; Safarikova, Jana; Baresova, Magdalena; Pivokonska, Lenka; Kopecka, Ivana

2014-03-15

4

The lipid composition of the unicellular green alga Chlamydomonas reinhardtii and the diatom Cyclotella meneghiniana investigated by MALDI-TOF MS and TLC.  

PubMed

The lipid composition of algae is crucial for numerous structural and physiological aspects, e.g. the integrity of the photosynthetic complexes and the functionality of membrane-embedded processes as the photosynthetic electron transport in thylakoids or the mitochondrial respiration. In this paper the lipid composition of the organic extracts of the green alga Chlamydomonas reinhardtii and the diatom Cyclotella meneghiniana are compared by using matrix-assisted laser desorption and ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) in combination with thin-layer chromatography (TLC). The combined methods enable quantitative evaluation of the individual lipid classes as well as the determination of the relative acyl compositions. It will be shown that both algae differ in (a) the lipid classes, (b) the relative contribution of the individual lipid classes and (c) the acyl compositions. Differences in the acyl composition concern particularly the mono- and digalactosyl diacylglycerols. Glycerol-trimethylhomoserine and phosphatidylethanolamine are exclusively detected in the C. reinhardtii extracts, whereas phosphatidylcholine is a characteristic lipid of C. meneghiniana. Furthermore, the proportion of the acidic lipids sulfoquinovosyl-diacylglycerol and phosphatidylglycerol is significantly higher in the diatom than in C. reinhardtii. PMID:17681288

Vieler, Astrid; Wilhelm, Christian; Goss, Reimund; Süss, Rosmarie; Schiller, Jürgen

2007-12-01

5

Detection of green algae (Chlorophyceae) for the diagnosis of drowning.  

PubMed

The plankton test (generally, diatom test) is one of the methods available to diagnose the cause of death of submerged bodies. The solubilization method using tissue solubilizer Soluene-350 was used in this study to detect not only diatoms but also green algae, based on the fact that the solubilizer does not digest the cell walls of green algae which are made from cellulose. Detection of green algae from organs of submerged cadavers is very informative to determine drowning in fresh water, and also in cases where only few diatoms are detected in the organs. PMID:7495686

Yoshimura, S; Yoshida, M; Okii, Y; Tokiyasu, T; Watabiki, T; Akane, A

1995-01-01

6

Red and Green Algal Origin of Diatom Membrane Transporters: Insights into Environmental Adaptation and Cell Evolution  

PubMed Central

Membrane transporters (MTs) facilitate the movement of molecules between cellular compartments. The evolutionary history of these key components of eukaryote genomes remains unclear. Many photosynthetic microbial eukaryotes (e.g., diatoms, haptophytes, and dinoflagellates) appear to have undergone serial endosymbiosis and thereby recruited foreign genes through endosymbiotic/horizontal gene transfer (E/HGT). Here we used the diatoms Thalassiosira pseudonana and Phaeodactylum tricornutum as models to examine the evolutionary origin of MTs in this important group of marine primary producers. Using phylogenomics, we used 1,014 diatom MTs as query against a broadly sampled protein sequence database that includes novel genome data from the mesophilic red algae Porphyridium cruentum and Calliarthron tuberculosum, and the stramenopile Ectocarpus siliculosus. Our conservative approach resulted in 879 maximum likelihood trees of which 399 genes show a non-lineal history between diatoms and other eukaryotes and prokaryotes (at the bootstrap value ?70%). Of the eukaryote-derived MTs, 172 (ca. 25% of 697 examined phylogenies) have members of both red/green algae as sister groups, with 103 putatively arising from green algae, 19 from red algae, and 50 have an unresolved affiliation to red and/or green algae. We used topology tests to analyze the most convincing cases of non-lineal gene history in which red and/or green algae were nested within stramenopiles. This analysis showed that ca. 6% of all trees (our most conservative estimate) support an algal origin of MTs in stramenopiles with the majority derived from green algae. Our findings demonstrate the complex evolutionary history of photosynthetic eukaryotes and indicate a reticulate origin of MT genes in diatoms. We postulate that the algal-derived MTs acquired via E/HGT provided diatoms and other related microbial eukaryotes the ability to persist under conditions of fluctuating ocean chemistry, likely contributing to their great success in marine environments.

Chan, Cheong Xin; Reyes-Prieto, Adrian; Bhattacharya, Debashish

2011-01-01

7

Red and green algal origin of diatom membrane transporters: insights into environmental adaptation and cell evolution.  

PubMed

Membrane transporters (MTs) facilitate the movement of molecules between cellular compartments. The evolutionary history of these key components of eukaryote genomes remains unclear. Many photosynthetic microbial eukaryotes (e.g., diatoms, haptophytes, and dinoflagellates) appear to have undergone serial endosymbiosis and thereby recruited foreign genes through endosymbiotic/horizontal gene transfer (E/HGT). Here we used the diatoms Thalassiosira pseudonana and Phaeodactylum tricornutum as models to examine the evolutionary origin of MTs in this important group of marine primary producers. Using phylogenomics, we used 1,014 diatom MTs as query against a broadly sampled protein sequence database that includes novel genome data from the mesophilic red algae Porphyridium cruentum and Calliarthron tuberculosum, and the stramenopile Ectocarpus siliculosus. Our conservative approach resulted in 879 maximum likelihood trees of which 399 genes show a non-lineal history between diatoms and other eukaryotes and prokaryotes (at the bootstrap value ?70%). Of the eukaryote-derived MTs, 172 (ca. 25% of 697 examined phylogenies) have members of both red/green algae as sister groups, with 103 putatively arising from green algae, 19 from red algae, and 50 have an unresolved affiliation to red and/or green algae. We used topology tests to analyze the most convincing cases of non-lineal gene history in which red and/or green algae were nested within stramenopiles. This analysis showed that ca. 6% of all trees (our most conservative estimate) support an algal origin of MTs in stramenopiles with the majority derived from green algae. Our findings demonstrate the complex evolutionary history of photosynthetic eukaryotes and indicate a reticulate origin of MT genes in diatoms. We postulate that the algal-derived MTs acquired via E/HGT provided diatoms and other related microbial eukaryotes the ability to persist under conditions of fluctuating ocean chemistry, likely contributing to their great success in marine environments. PMID:22195008

Chan, Cheong Xin; Reyes-Prieto, Adrian; Bhattacharya, Debashish

2011-01-01

8

How-to-Do-It: Diatoms: The Ignored Alga in High School Biology.  

ERIC Educational Resources Information Center

Provides historical background, descriptions, uses and basis for identification of diatoms. Explains collection, dry-mount cleaning, and preparation procedures of the algae. Cites additional resources. (RT)

Hungerford, James J.

1988-01-01

9

PPR proteins of green algae.  

PubMed

Using the repeat finding algorithm FT-Rep, we have identified 154 pentatricopeptide repeat (PPR) proteins in nine fully sequenced genomes from green algae (with a total of 1201 repeats) and grouped them in 47 orthologous groups. All data are available in a database, PPRdb, accessible online at http://giavap-genomes.ibpc.fr/ppr. Based on phylogenetic trees generated from the repeats, we propose evolutionary scenarios for PPR proteins. Two PPRs are clearly conserved in the entire green lineage: MRL1 is a stabilization factor for the rbcL mRNA, while HCF152 binds in plants to the psbH-petB intergenic region. MCA1 (the stabilization factor for petA) and PPR7 (a short PPR also acting on chloroplast mRNAs) are conserved across the entire Chlorophyta. The other PPRs are clade-specific, with evidence for gene losses, duplications, and horizontal transfer. In some PPR proteins, an additional domain found at the C terminus provides clues as to possible functions. PPR19 and PPR26 possess a methyltransferase_4 domain suggesting involvement in RNA guanosine methylation. PPR18 contains a C-terminal CBS domain, similar to the CBSPPR1 protein found in nucleoids. PPR16, PPR29, PPR37, and PPR38 harbor a SmR (MutS-related) domain similar to that found in land plants pTAC2, GUN1, and SVR7. The PPR-cyclins PPR3, PPR4, and PPR6, in addition, contain a cyclin domain C-terminal to their SmR domain. PPR31 is an unusual PPR-cyclin containing at its N terminus an OctotricoPeptide Repeat (OPR) and a RAP domain. We consider the possibility that PPR proteins with a SmR domain can introduce single-stranded nicks in the plastid chromosome. PMID:24021981

Tourasse, Nicolas J; Choquet, Yves; Vallon, Olivier

2013-09-01

10

TEMPERATURE AND MANGANESE AS DETERMINING FACTORS IN THE PRESENCE OF DIATOM OR BLUE-GREEN ALGAL FLORAS IN STREAMS*  

PubMed Central

Diatoms are usually the major component of the algal flora in many streams, although green and blue-green algae may be present. These experiments were designed to determine if high temperature or a shift in the chemical composition of the water might bring about a dominance of blue-green algae and/or green algae rather than a dominance of diatoms in the algal flora. The results of these experiments indicate that an average temperature of 34° to 38°C results in a shift of dominance in the algal flora from diatoms to blue-green algae. Furthermore, a blue-green and green algal flora of species typically found in organically polluted water in favored if the manganese content is a few parts per billion. If the manganese content averaged 0.02-0.043 mg/liter in the natural stream to 0.04-0.28 mg/liter in the recycled water experiment, a diatom flora remained dominant.

Patrick, Ruth; Crum, Bowman; Coles, John

1969-01-01

11

Environmental Requirements of Blue-Green Algae.  

National Technical Information Service (NTIS)

The problem of accelerated eutrophication has many facets, and some are being examined through research to find the keys for solution. The symposium was held to fulfill the need to understand better the environmental requirements of blue-green algae. The ...

1967-01-01

12

Blue-green algae toxicosis in cattle.  

PubMed

Twenty-four of 175 heifers died after ingesting water from a stock pond containing blue-green algae (genus Microcystis) in southern Colorado. Affected cattle were found dead or had signs of nervousness, and were recumbent, weak, anorectic, and hypersensitive to noise when first examined. All cattle died within 3 days after the onset of signs. At necropsy, the rumen contained blue-green algae, and the liver was larger than normal, friable, and dark red. The most important histologic lesion was hepatocyte degeneration and necrosis. Intraperitoneal administration of lyophilized cell material from the bloom caused hepatic necrosis and death in mice, and water from the pond had clumps of cells surrounded by a clear calyx, consistent with the appearance of organisms of the genus Microcystis. Samples of pond water were examined by means of high-pressure liquid chromatography; microcystin-LR, one of the hepatotoxins produced by Microcystis spp, was found. Chromatography may be useful in the diagnosis of blue-green algae toxicosis. PMID:9838962

Puschner, B; Galey, F D; Johnson, B; Dickie, C W; Vondy, M; Francis, T; Holstege, D M

1998-12-01

13

Photoreversible Pigment: Occurrence in a Blue-Green Alga  

Microsoft Academic Search

A new photoreversible pigment has been isolated from the blue-green alga Tolypothrix tenuis. This pigment bears certain resemblances to phytochrome, except that absorption maxima for the two forms are in the green and red portions of the spectrum instead of the red and far-red. The pigment may control diverse differentiative processes in blue-green algae.

Joseph Scheibe

1972-01-01

14

Hydrocarbons in green and blue-green algae.  

PubMed

Liquid column chromatography and thin-layer chromatography were used to determine the total content of hydrocarbons and gas chromatography was used to evaluate composition of hydrocarbons in green algae (Chlorella kessleri, C. vulgaris, Chlorella sp., Scenedesmus acutus, S. acuminatus, S. obliquus) and the blue-green alga (Spirulina platensis) cultivated under autotrophic or heterotrophic conditions. In C. kessleri cultivated under heterotrophic conditions the content of hydrocarbons was found to be about 10(-2)% (per dry mass), whereas under autotrophic conditions it was about 10(-3)% (per dry mass). The highest content of hydrocarbons was detected in species of the genus Scenedesmus cultivated autotrophically (10(-1)%). Heptadecane and hexacosane were found as major alkanes, 1-heptadecene was detected among alkenes. PMID:6816708

Rezanka, T; Zahradník, J; Podojil, M

1982-01-01

15

The chloroplast pigments of some green and yellow-green algae  

Microsoft Academic Search

Pigment analysis carried out by thin-layer chromatography confirms that Chlorocloster engadinensis Vischer, C. solani George and Nephrodiella brevis Vischer are all green algae (Chlorophyceae) and not yellow-green algae (Xanthophyceae) as has been suggested. The pigments of Coccomyxa elongata Jaag, C. simplex (Pringsheim) Mainx and Pyrobotrys stellata Korshikov are also typical of green algae. The pigments of Pleurochloris commutata Pascher, P.

S. J. Whittle; P. J. Casselton

1969-01-01

16

Steroids from green alga Chaetomorpha basiretorsa Setchell  

NASA Astrophysics Data System (ADS)

Six steroids have been isolated from ethanolic extract of green alga Chaetomorpha basiretorsa Setchell by a combination of repeated normal phase silica gel and Sephadex LH-20 gel column chromatography as well as recrystallization. Using spectroscopic methods including MS and NMR, their structures were determined as ?-lawsaritol (1), saringosterol (2), 24-hydroperoxy-24-vinyl-cholesterol (3), ?-stigmasterol (4), stigmast-4-en-3?, 6?-diol (5), 29-hydroxystigmasta-5, 24 (28)-dien-3?-ol (6). All these compounds were obtained from this genus for the first time and they were inactive (IC50>10 ?g /ml) against KB, Bel-7402, PC-3M, Ketr 3 and MCF-7 cell lines.

Shi, Dayong; Fan, Xiao; Sun, Jie; Han, Lijun; Shi, Jiangong

2008-11-01

17

ELECTRON MICROSCOPE STUDIES ON BLUE-GREEN ALGAE  

Microsoft Academic Search

Several species of blue-green algae were studied in thin sections with the electron microscope. Our electron micrographs confirm the view that the cell of blue-green algae is different and simpler in organization than the typical plant or animal cell. On the other hand, the general pattern of ultrastructure is the same as that found in bacteria and Streptomyces. The cell

HANS RIS; R. N. SINGH

1961-01-01

18

Effect of pesticides on blue-green algae  

Microsoft Academic Search

Effect of pesticides, i.e., Benzene Hexachloride, Lindane, Diazinon and Endrin that are often used in India was observed on nitrogen-fixing blue-green algae Cylindrospermum sp., Aulosira fertilissima Ghose and aerobically non-nitrogen-fixing blue-green alga Plectonema boryanum strain 594. These algae were sensitive for BHC in comparison to other pesticides. A. fertilissima and P. boryanum were more resistant than Cylindrospermum sp.

P. K. Singh

1973-01-01

19

Viable Cyanobacteria and Green Algae from the Permafrost Darkness  

SciTech Connect

This review represents an overview of the existence, distribution and abundance of the photoautotrophic microorganisms in the deep subsurface permafrost of the Northeast Russia and McMurdo Dry Valleys, Antarctica. The morphology, growth rate, spectral properties, phylogenetic position of the viable permafrost green algae and cyanobacteria have been studied. Viable photoautotrophs were represented by unicellular green algae and filamentous cyanobacteria with low growth rate. Spectral studies of ancient cyanobacteria and green algae did not reveal any significant differences between them and their contemporary relatives. Phylogenetic analyses have shown that permafrost photoautotrophs were closely related to strains and more often to uncultured environmental clones from cold regions.

Vishnivetskaya, Tatiana A [ORNL

2009-01-01

20

Phylogeny and Molecular Evolution of the Green Algae  

Microsoft Academic Search

The green lineage (Viridiplantae) comprises the green algae and their descendants the land plants, and is one of the major groups of oxygenic photosynthetic eukaryotes. Current hypotheses posit the early divergence of two discrete clades from an ancestral green flagellate. One clade, the Chlorophyta, comprises the early diverging prasinophytes, which gave rise to the core chlorophytes. The other clade, the

Frederik Leliaert; David R. Smith; Hervé Moreau; Matthew D. Herron; Heroen Verbruggen; Charles F. Delwiche; Olivier De Clerck

2012-01-01

21

Blue-Green Algae and Freshwater Carbonate Deposits  

Microsoft Academic Search

Twenty-seven contemporary freshwater carbonate deposits were investigated (26 in the British Isles and 1 in S. Australia). The blue-green algae Schizothrix calcicola and Microcoleus vaginatus occurred at 23 of the sites. The remaining sites represented areas where deposition had ceased. About 1% of the dry mass of the deposits consisted of Cyanophyta. The assimilation rates of these algae, measured by

A. Pentecost

1978-01-01

22

Uptake of Glycine by Blue-Green Algae.  

National Technical Information Service (NTIS)

Uptake of glycine-14C was measured in 3 species of blue-green algae, viz Oscillatoria jasorvensis, Gloeotrichia pisum and Microcystis aeruginosa. Radioactivity in breis of Oscillatoria increased with increasing time of incubation in glycine-14C solution. ...

G. C. Stephens B. S. Vaidya O. P. Saxena

1968-01-01

23

Hydrogenases in green algae: do they save the algae's life and solve our energy problems?  

Microsoft Academic Search

Green algae are the only known eukaryotes with both oxygenic photosynthesis and a hydrogen metabolism. Recent physiological and genetic discoveries indicate a close connection between these metabolic pathways. The anaerobically inducible hydA genes of algae encode a special type of highly active [Fe]-hydrogenase. Electrons from reducing equivalents generated during fermentation enter the photosynthetic electron transport chain via the plastoquinone pool.

Thomas Happe; Anja Hemschemeier; Martin Winkler; Annette Kaminski

2002-01-01

24

Nitrogen fixation by unicellular blue-green algae  

Microsoft Academic Search

The ability of some unicellular blue-green algae to grow at the expense of N2 under aerobic conditions has been confirmed and the distribution of this property in the Chroococcaceae has been investigated. It appears to be confined to strains with spherical cells enclosed by the multilaminate sheaths characteristic of the genus Gloeocapsa. Only two unicellular blue-green algae of this type

Rosmarie Rippka; Alasdair Neilson; Riyo Kunisawa; Germaine Cohen-Bazire

1971-01-01

25

Photosynthetic H 2 metabolism in Chlamydomonas reinhardtii (unicellular green algae)  

Microsoft Academic Search

Unicellular green algae have the ability to operate in two distinctly different environments (aerobic and anaerobic), and\\u000a to photosynthetically generate molecular hydrogen (H2). A recently developed metabolic protocol in the green alga Chlamydomonas reinhardtii permitted separation of photosynthetic O2-evolution and carbon accumulation from anaerobic consumption of cellular metabolites and concomitant photosynthetic H2-evolution. The H2 evolution process was induced upon sulfate

Anastasios Melis

2007-01-01

26

Phosphorus-Limited Growth of a Green Alga and a Blue-Green Alga  

PubMed Central

The phosphorus-limited growth kinetics of the chlorophyte Scenedesmus quadricauda and the cyanophyte Synechococcus Nägeli were studied by using batch and continuous culturing techniques. The steady-state phosphate transport capability and the phosphorus storage capacity is higher in S. Nägeli than in S. quadricauda. Synechococcus Nägeli can also deplete phosphate to much lower levels than can S. quadricauda. These results, along with their morphological characteristics, were used to construct partial physiological profiles for each organism. The profiles indicate that this unicellular cyanophyte (cyanobacterium) is better suited for growth in phosphorus-limited oligotrophic niches than is this chlorophyte (green alga).

Lang, Douglas S.; Brown, Edward J.

1981-01-01

27

Phosphorus-limited growth of a green alga and a blue-green alga  

SciTech Connect

The phosphorus-limited growth kinetics of the chlorophyte Scenedesmus quadricauda and the cyanophyte Synechococcus Nageli were studied by using batch and continuous culturing techniques. The steady-state phosphate transport capability and the phosphorus storage capacity is higher in S. Nageli than in S. quadricauda. Synechococcus Nageli can also deplete phosphate to much lower levels than can S. quadricauda. These results, along with their morphological characteristics, were used to construct partial physiological profiles for each organism. The profiles indicate that this unicellular cyanophyte (cyanobacterium) is better suited for growth in phosphorus-limited oligotrophic niches than is this chlorophyte (green alga). (Refs. 44).

Lang, D.S.; Brown, E.J.

1981-12-01

28

The exploitation of beds of green algae by brent geese  

NASA Astrophysics Data System (ADS)

Brent geese on the Norfolk coast occurred on beds of green algae (primarily Enteromorpha spp.) at low tide during autumn and early winter. Feeding was the main activity. Numbers of geese started to decline when the biomass of algae had fallen to c. 5 g dry wt m -2, and the birds rarely occurred on the beds after the biomass had reached c. 1 g dry wt m -2 in late November. The biomass of ungrazed algae did not decline as rapidly, nor to as low a level as that of grazed algae during the winter, showing that grazing by geese was partly responsible for the earlier decline in this food source.

Summers, Ronald W.

1990-07-01

29

Green Autofluorescence in Dinoflagellates, Diatoms, and Other Microalgae and Its Implications for Vital Staining and Morphological Studies? †  

PubMed Central

Green autofluorescence (GAF) has been described in the short flagellum of golden and brown algae, the stigma of Euglenophyceae, and cytoplasm of different life stages of dinoflagellates and is considered by some researchers a valuable taxonomic feature for dinoflagellates. In addition, green fluorescence staining has been widely proposed or adopted to measure cell viability (or physiological state) in areas such as apoptosis of phytoplankton, pollutant stresses on algae, metabolic activity of algae, and testing treatment technologies for ships' ballast water. This paper reports our epifluorescence microscopic observations and quantitative spectrometric measurements of GAF in a broad phylogenetic range of microalgae. Our results demonstrate GAF is a common feature of dinoflagellates, diatoms, green algae, cyanobacteria, and raphidophytes, occurs in the cytoplasm and particularly in eyespots, accumulation bodies, spines, and aerotopes, and is caused by molecules other than chlorophyll. GAF intensity increased with time after cell death or fixation and with excitation by blue or UV light and was affected by pH. GAF of microalgae may be only of limited value in taxonomy. It can be strong enough to interfere with the results of green fluorescence staining, particularly when stained samples are observed microscopically. GAF is useful, however, for microscopic study of algal morphology, especially to visualize cellular components such as eyespots, nucleus, aerotopes, spines, and chloroplasts. Furthermore, GAF can be used to visualize and enumerate dinoflagellate cysts in marine and estuarine sediments in the context of anticipating and monitoring harmful algal blooms and in tracking potentially harmful dinoflagellates transported in ships' ballast tanks.

Tang, Ying Zhong; Dobbs, Fred C.

2007-01-01

30

Green algae to land plants: An evolutionary transition  

Microsoft Academic Search

Studies focused upon the evolutionary transition from ancestral green algae to the earliest land plants are important from\\u000a a range of ecological, molecular and evolutionary perspectives. A substantial suite of ultrastructural, biochemical and molecular\\u000a data supports the concept that land plants (embryophytes) are monophyletically derived from an ancestral charophycean alga.\\u000a However, the details of phylogenetic branching patterns linking extant charophytes

Linda E. Graham

1996-01-01

31

Studies on nitrogen fixation by blue-green algae  

Microsoft Academic Search

1.The unicellular blue-green alga Chlorogloea fritschii Mitra has been isolated in pure bacteria-free culture.2.Evidence showing that this alga is able to fix elementary nitrogen has been obtained by determinations by the micro-Kjeldahl method of increases in total combined nitrogen in culture and also by demonstration of the uptake of elementary nitrogen in a closed culture system by measurement of nitrogen\\/argon

P. Fay; G. E. Fogg

1962-01-01

32

The Future is Green: On the Biotechnological Potential of Green Algae  

Microsoft Academic Search

\\u000a There are two main players that form the basis of nearly all global ecosystems in converting solar energy to biomass: algae\\u000a and plants. While plants are omnipresent in public discussions dealing with such topics as climate change, bioreactors, biofuels\\u000a and green biotechnology, the role and potential of algae is usually known only to experts. However, algae are present as primary

Werner Reisser

33

Energy transfer from carotenoids to chlorophyll in blue-green, red and green algae and greening bean leaves  

Microsoft Academic Search

From fluorescence action spectra, fluorescence spectra and absorption spectra measured at room temperature and at 77 °K of light petroleum (b.p. 40–60°)-treated and normal chloroplasts, it is concluded that: \\u000a\\u000a1. 1. In blue-green and red algae energy transfer from ?-carotene to chlorophyll occurs in Photosystem I exclusively.\\u000a\\u000a2. 2. In green algae and greening bean leaves energy transfer from ?-carotene

J. C. Goedheer

1969-01-01

34

Ecophysiological performance of an urban strain of the aeroterrestrial green alga Klebsormidium sp. (Klebsormidiales, Klebsormidiophyceae)  

Microsoft Academic Search

Aeroterrestrial green algae are among the most ubiquitous members of the microbial flora colonizing aerial surfaces. Filamentous green algae, in particular, produce large populations in several natural and artificial habitats. In recent years it has been shown that the bases of the walls of urban environments are frequently colonized by filamentous green algae. However, information concerning the physiology of these

Ulf Karsten; Fabio Rindi

2010-01-01

35

On site photosynthetic performance of Atlantic green algae  

Microsoft Academic Search

Photosynthetic performance was measured on site in four common Atlantic green algae, Asparagopsis taxiforme, Valonia utricularia, Caulerpa racemosa and Codium taylori, in Gran Canaria, Canary Islands. The photosynthetic quantum yield was determined with a portable PAM instrument and with a diving PAM in the water column. Solar radiation was measured continuously above and in the water column by means of

Donat-P Häder; Markus Porst; Michael Lebert

2000-01-01

36

Adhesion strength of settled spores of the green alga Enteromorpha  

Microsoft Academic Search

Strengths of attachment of spores of the green fouling alga Enteromorpha to glass have been measured using a modified water jet apparatus. Surface pressures of ?250 kPa were required to quantitatively remove attached spores after 4 h contact with a surface. The development of adhesive and cohesive strength is highly time-dependent; after 8 h in contact with a surface spores

J A Finlay; Maureen E Callow; M P Schultz; G W Swain; J A Callow

2002-01-01

37

Gas Vacuole Development in a Blue-Green Alga  

Microsoft Academic Search

De novo production of gas vacuoles can be induced in the blue-green alga Nostoc muscorum by transferring the cells from a defined medium to distilled water. The unusual ultrastructure of the gas vacuole membranes permits their easy recognition when specimens are prepared for electron microscopy by freeze-etching. The youngest gas vacuoles are biconical organelles; 48 hours after induction the gas

J. Robert Waaland; Daniel Branton

1969-01-01

38

Toxins of a Blue-Green Alga: Similarity to Saxitoxin  

Microsoft Academic Search

Toxins were isolated from the freshwater blue-green alga Aphanizomenon flos-aquae. The toxic fractions were characterized by paper and thin-layer chromatography, isolation characteristics, infrared spectra, physiological activity, and reactivity with specific color reagents. The toxic fractions appear to be similar, if not identical, to saxitoxin (paralytic shellfish toxin), which is produced by the marine dinoflagellate Gonyaulax catenella.

Eugene Jackim; John Gentile

1968-01-01

39

Bioactive natural products from blue-green algae  

Microsoft Academic Search

Since 1981 we have cultured and prepared lipophilic and hydrophilic extracts from more than 1500 strains representing some 400 species of blue-green algae. Screening for a wide variety of potentially useful bioactivities, including cytotoxic, multi-drug-resistance reversal, antifungal, and antiviral effects, has led to the discovery and identification of numerous novel bioactive metabolites including peptides, macrolides and glycosides.

Gregory M. L. Patterson; Linda K. Larsen; Richard E. Moore

1994-01-01

40

Mucilage secretion and the movements of blue-green algae  

Microsoft Academic Search

Summary Recent discoveries of ultrastructures which might be involved in the gliding movements of blue-green algae have been reviewed, and in the light of these discoveries the role of mucilage secretion in movement has been reconsidered. The formation and behaviour of mucilage rings in filaments ofAnabaena cylindrica is described. The behaviour of the mucilage rings indicates that each cell has

A. E. Walsby

1968-01-01

41

Marine blue-green algae have a unique osmoregulatory system  

Microsoft Academic Search

Currently, blue-green algae are classified as either freshwater or marine depending on the ionic requirements of the strain, not on the type of habitat from which the strain was isolated. As a result many strains isolated from saline environments are classified as freshwater strains. New parameters were sought which might correlate better the physiology of marine strains with their habitat.

M. A. Mackay; R. S. Norton; L. J. Borowitzka

1983-01-01

42

Fatty acid amides from freshwater green alga Rhizoclonium hieroglyphicum.  

PubMed

Freshwater green algae Rhizoclonium hieroglyphicum growing in the Ural Mountains were examined for their fatty acid amides using capillary gas chromatography-mass spectrometry (GC-MS). Eight fatty acid amides were identified by GC-MS. (Z)-9-octadecenamide was found to be the major component (2.26%). PMID:11014298

Dembitsky, V M; Shkrob, I; Rozentsvet, O A

2000-08-01

43

Biosorption of reactive dyes on the green alga Chlorella vulgaris  

Microsoft Academic Search

Biosorption of three vinyl sulphone type reactive dyes (Remazol Black B (RB), Remazol Red RR (RR) and Remazol Golden Yellow RNL (RGY)) onto dried Chlorella vulgaris, a green alga was investigated in a batch system. The algal biomass exhibited the highest dye uptake capacity at the initial pH value of 2.0 for all dyes. The effect of temperature on equilibrium

Zümriye Aksu; Sevilay Tezer

2005-01-01

44

Photosynthetic Hydrogen and Oxygen Production by Green Algae.  

National Technical Information Service (NTIS)

Photosynthesis research at Oak Ridge National Laboratory is focused on hydrogen and oxygen production by green algae in the context of its potential as a renewable fuel and chemical feed stock. Beginning with its discovery by Gaffron and Rubin in 1942, mo...

E. Greenbaum J. W. Lee

1999-01-01

45

Fatty acid as markers to demonstrating trophic relationships among diatoms, rotifers and green-lipped mussels  

Microsoft Academic Search

Green-lipped mussels Perna viridis, collected from Peng Chau, Hong Kong were allotted into two treatment groups, each containing three experimental tanks. The first treatment group comprised of mussels fed with the diatom Thalassiosira pseudonana only, whereas the second treatment group contained mussels fed with the marine rotifer Brachionus plicatilis, which was in turn fed with diatom T. pseudonana. The mussels

Paul K. S. Shin; K. M. Yip; W. Z. Xu; W. H. Wong; S. G. Cheung

2008-01-01

46

Growth interactions among blue-green (Anabaena Oscillarioides, Microcystis aeruginosa) and green (Chlorella sp.) algae  

Microsoft Academic Search

The growth interactions amongst the blue-green algal species Anabaena oscillarioides, Microcystis aeruginosa and the green alga, Chlorella sp. were studied both in mixed cultures and in filter cultures separated by a membrane filter in the two arms of an interaction U-tube. The role of nutrients especially phosphate upon the interaction has also been studied.

Catherine W. Y. Lam; Warwick B. Silvester

1979-01-01

47

Cycloartane triterpenes from marine green alga Cladophora fascicularis  

NASA Astrophysics Data System (ADS)

Six cycloartanes were isolated from ethanol extract of marine green alga Cladophora fascicularis by column chromatography. Procedure of isolation and description of these compounds are given in this paper. The structures were elucidated as (1). 24-hydroperoxycycloart-25- en-3?-ol; (2). cycloart-25-en-3? 24-diol; (3). 25-hydroperoxycycloart-23-en-3?-ol; (4). cycloart-23-en-3?, 25-diol; (5). cycloart-23, 25-dien-3?-ol; and (6). cycloart-24-en-3?-ol by spectroscopic (MS, ID and 2D NMR) data analysis. Cycloartane derivatives are widely distributed in terrestrial plants, but only few were obtained in the alga. All these compounds that have been isolated from terrestrial plants, were found in the marine alga for the first time.

Huang, Xinping; Zhu, Xiaobin; Deng, Liping; Deng, Zhiwei; Lin, Wenhan

2006-12-01

48

Seasonal changes of ?-tocopherol in green marine algae (Caulerpa genus).  

PubMed

Marine algae are a promising source of beneficial compounds for human use. Among these, pro-vitamin A carotenoids and vitamins B, C, and E stand out. The objective of this study was to investigate seasonal variation of ?-tocopherol levels in 5 species of green marine algae of the Caulerpa genus. This research was carried out with both fresh and dry specimens; and, in addition, differences arising as a result of the drying process were examined. Analyses were carried out by high-performance liquid chromatography (HPLC) using an isocratic system and a reversed-phase C-18 column. The distribution of ?-tocopherol throughout the year in?Caulerpa?genus was variable. All samples of both fresh and dried algae contained ?-tocopherol, except for the dried?C. racemosa?from March 2006. The drying process was responsible for losses of ?-tocopherol ranging from 21% to 93%. PMID:22417426

Pires-Cavalcante, Kelma Maria Dos Santos; de Alencar, Daniel Barroso; de Sousa, Márcia Barbosa; Sampaio, Alexandre Holanda; Saker-Sampaio, Silvana

2011-01-01

49

Blue-Green Algae: Fine Structure of the Gas Vacuoles  

Microsoft Academic Search

The gas vacuoles seen in several species of blue-green algae under the light microscope are shown by electron microscopy to correspond to packed arrays of cylindrical, electron-transparent vesicles. Single vesicles average 75 millimicrons in diameter, range from 0.2 micron to 1.0 micron in length, have conical ends, and are bounded by a single membrane 2 millimicrons wide. The reversible disappearance

C. C. Bowen; T. E. Jensen

1965-01-01

50

Mathematical simulation of photophobic responses in blue-green algae  

SciTech Connect

A computer model is described to simulate photophobic reversal of blue-green algae. The model is based on electrical potential changes within the cells, which are treated as separate compartments. The updating of potentials is accomplished through iterative calculation of recurrence equations, permitting easy programming for computer calculation. The influence of a number of conditions on photophobic reversal has been studied, and the predictions of the model have been verified by experiments with the living organisms.

Hader, D.P.; Burkart, U.

1982-01-01

51

Antioxidant role of astaxanthin in the green alga Haematococcus pluvialis  

Microsoft Academic Search

The green unicellular alga, Haematococcus pluvialis has two antioxidative mechanisms against environmental oxidative stress: antioxidative enzymes in vegetative cells and the\\u000a antioxidative ketocarotenoid, astaxanthin, in cyst cells. We added a reagent that generates superoxide anion radicals (O2\\u000a ?), methyl viologen, to mature and immature cysts of H. pluvialis. Tolerance to methyl viologen was higher in mature than in immature cysts.

M. Kobayashi; T. Kakizono; N. Nishio; S. Nagai; Y. Kurimura; Y. Tsuji

1997-01-01

52

Dynamics of photosystem II heterogeneity in Dunaliella salina (green algae)  

Microsoft Academic Search

Based on the electron-transport properties on the reducing side of the reaction center, photosystem II (PS II) in green plants and algae occurs in two distinct forms. Centers with efficient electron-transport from QA to plastoquinone (QB-reducing) account for 75% of the total PS II in the thylakoid membrane. Centers that are photochemically competent but unable to transfer electrons from QA

Jeanne E. Guenther; Anastasios Melis

1990-01-01

53

Diatoms  

Microsoft Academic Search

The basic requirements for diatom analysis have changed little over the last few decades in terms of sampling, slide preparation,\\u000a microscopy and taxonomy but, on the other hand, there have been major improvements in our knowledge of diatom distribution\\u000a and ecology and a revolution in our ability to analyse diatom data. These changes have been driven by the increasing recognition

Richard W. Battarbee; Vivienne J. Jones; Roger J. Flower; Nigel G. Cameron; Helen Bennion; Laurence Carvalho; Stephen Juggins

54

Toxicity of oxide nanoparticles to the green algae Chlorella sp  

Microsoft Academic Search

Increasing studies focus on nanotoxicity, but many unknowns are remaining to be investigated. This study examined toxicities of four varieties of oxide nanoparticles (Al2O3, SiO2, ZnO, and TiO2) to the green algae Chlorella sp. Nanoparticulate Al2O3, SiO2, and TiO2 (DJ3, rutile) had no significant toxicity, whereas nano-ZnO and nano-TiO2 (HR3, anatase) greatly inhibited the algal growth with 6d EC30 of

Jing Ji; Zhifeng Long; Daohui Lin

2011-01-01

55

Interaction of organic solvents with the green alga Chlorella pyrenoidosa  

SciTech Connect

Solvents are often a component of bioassay systems when water-insoluble toxicants are being tested. These solvents must also be considered as xenobiotics and therefore, as potential toxicants in the bioassay. However, the effects of solvents on the organisms being tested and their possible interaction with the test compound are often overlooked by researchers. The purpose of the present study was to compare the inhibitory effects of six solvents commonly used in pesticide bioassays towards growth of the common green alga Chlorella pyrenoidosa, and to examine the occurrence of solvent-pesticide interactions with this organism.

Stratton, G.W.; Smith, T.M. (Nova Scotia Agricultural College, Truro (Canada))

1988-06-01

56

The presence of diatom algae in a tracheal wash from a German Wirehaired Pointer with aspiration pneumonia.  

PubMed

A 7-year-old spayed female German Wirehaired Pointer was presented with difficulty breathing after being found seizing in a water-filled drainage ditch while out hunting. Aspirates from a tracheal wash contained numerous degenerate neutrophils, fewer macrophages, some of which contained basophilic debris, low numbers of extracellular diatoms, and a single intracellular short bacterial rod. As the dog continued to clinically decline and could not be weaned from oxygen support, the owners chose euthanasia. The major necropsy finding was a severe granulomatous bronchopneumonia that was likely due to aspiration of foreign material based on the microscopic presence of plant-like material, bi-refringent crystalline material, non-cellular debris, and occasional fungal structures. Diatoms are a class of algae that live primarily in water. Diatom analysis has been used, with some controversy, in human forensics to assist in documenting drowning as the cause of death. In this case, given the clinical history, the presence of diatoms and inflammation in the tracheal wash were interpreted as a likely result of the aspiration of surface water. To our knowledge, this is the first reported case of diatoms observed in a cytologic specimen in a nonhuman mammal with aspiration pneumonia. PMID:23647227

Benson, Catherine J; Edlund, Mark B; Gray, Sarah; Powell, Lisa; Paulin-Curlee, Geisa; Armien, Anibal; Overmann, Jed A

2013-06-01

57

Photosynthetic Hydrogen and Oxygen Production by Green Algae  

SciTech Connect

Photosynthesis research at Oak Ridge National Laboratory is focused on hydrogen and oxygen production by green algae in the context of its potential as a renewable fuel and chemical feed stock. Beginning with its discovery by Gaffron and Rubin in 1942, motivated by curiosity-driven laboratory research, studies were initiated in the early 1970s that focused on photosynthetic hydrogen production from an applied perspective. From a scientific and technical point of view, current research is focused on optimizing net thermodynamic conversion efficiencies represented by the Gibbs Free Energy of molecular hydrogen. The key research questions of maximizing hydrogen and oxygen production by light-activated water splitting in green algae are: (1) removing the oxygen sensitivity of algal hydrogenases; (2) linearizing the light saturation curves of hotosynthesis throughout the entire range of terrestrial solar irradiance-including the role of bicarbonate and carbon dioxide in optimization of photosynthetic electron transpor;t and (3) constructing real-world bioreactors, including the generation of hydrogen and oxygen against workable back pressures of the photoproduced gases.

Greenbaum, E.; Lee, J.W.

1999-08-22

58

Photosynthetic hydrogen and oxygen production by green algae  

SciTech Connect

An overview of photosynthetic hydrogen and oxygen production by green algae in the context of its potential as a renewable chemical feed stock and energy carrier is presented. Beginning with its discovery by Gaffron and Rubin in 1942, motivated by curiosity-driven laboratory research, studies were initiated in the early 1970s that focused on photosynthetic hydrogen production from an applied perspective. From a scientific and technical point of view, current research is focused on optimizing net thermodynamic conversion efficiencies represented by the Gibbs Free Energy of molecular hydrogen. The key research questions of maximizing hydrogen and oxygen production by light-activated water splitting in green algae are (1) removing the oxygen sensitivity of algal hydrogenases; (2) linearizing the light saturation curves of photosynthesis throughout the entire range of terrestrial solar irradiance--including the role of bicarbonate and carbon dioxide in optimization of photosynthetic electron transport and (3) the minimum number of light reactions that are required to split water to elemental hydrogen and oxygen. Each of these research topics is being actively addressed by the photobiological hydrogen research community.

Greenbaum, E.; Lee, J.W.

1997-12-31

59

Complete sequence of the mitochondrial genome of a diatom alga Synedra acus and comparative analysis of diatom mitochondrial genomes.  

PubMed

The first two mitochondrial genomes of marine diatoms were previously reported for the centric Thalassiosira pseudonana and the raphid pennate Phaeodactylum tricornutum. As part of a genomic project, we sequenced the complete mitochondrial genome of the freshwater araphid pennate diatom Synedra acus. This 46,657 bp mtDNA encodes 2 rRNAs, 24 tRNAs, and 33 proteins. The mtDNA of S. acus contains three group II introns, two inserted into the cox1 gene and containing ORFs, and one inserted into the rnl gene and lacking an ORF. The compact gene organization contrasts with the presence of a 4.9-kb-long intergenic region, which contains repeat sequences. Comparison of the three sequenced mtDNAs showed that these three genomes carry similar gene pools, but the positions of some genes are rearranged. Phylogenetic analysis performed with a fragment of the cox1 gene of diatoms and other heterokonts produced a tree that is similar to that derived from 18S RNA genes. The introns of mtDNA in the diatoms seem to be polyphyletic. This study demonstrates that pyrosequencing is an efficient method for complete sequencing of mitochondrial genomes from diatoms, and may soon give valuable information about the molecular phylogeny of this outstanding group of unicellular organisms. PMID:20309551

Ravin, Nikolai V; Galachyants, Yuri P; Mardanov, Andrey V; Beletsky, Alexey V; Petrova, Darya P; Sherbakova, Tatyana A; Zakharova, Yuliya R; Likhoshway, Yelena V; Skryabin, Konstantin G; Grachev, Mikhail A

2010-06-01

60

Defined Media for Growth and Gamete Production by the Green Alga, Oedogonium cardiacum1  

PubMed Central

Defined media consisting of inorganic salts and vitamin B12 are described for the male and female filaments of the green alga, Oedogonium cardiacum. These media provide for a maximal growth rate and for the induction of oogonia and antheridia under the prescribed conditions. The maximal amounts of growth, based on dry weight measurements, compare favorably with other green algae.

Hill, G. J. C.; Machlis, Leonard

1970-01-01

61

Ingestion, assimilation, survival, and reproduction by Daphnia pulex fed seven species of blue-green algae  

Microsoft Academic Search

Daphnia p&x (Crustacea, Cladocera) was fed the blue-green algae (Cyanophyceae) Anacystis nidulans, Synechococcus elongata, S. cedrorum, Merismopedia sp., Anabaena flos- aquae, Synechocystis sp., and Gloeocapsa alpicola. The green algae ( Chlorophyceae) Ankis- trodesmus falcatus and Chlorella uulgaris were used for comparison. Direct observations were made of D. pulex feeding in depression slides filled with the test food. Food labeled with

DEAN E. ARNOLD

1971-01-01

62

Host–parasite relationship of the geoduck Panopea abbreviata and the green alga Coccomyxa parasitica in the Argentinean Patagonian coast  

Microsoft Academic Search

The association of the geoduck Panopea abbreviata and the green alga Coccomyxa parasitica is described. The identity of the green alga was confirmed by molecular studies; the alga was found within the hemocytes that infiltrate the connective tissue of the geoduck siphons. Cytological characteristics of hemocytes were not altered by algal infection; very often the algae were seen enveloped by

Nuria Vázquez; Francisco Rodríguez; Cristián Ituarte; Javier Klaich; Florencia Cremonte

2010-01-01

63

Rôle of blue-green algae and different methods of partial soil sterilization on rice yield  

Microsoft Academic Search

Summary  Results of experiments during three consecutive seasons on the rôle of blue-green algae in combination with partial soil sterilization\\u000a and chemical nutrients indicate high responses to algae inoculation and a fertility build-up of the soil. It is also seen\\u000a that blue-green algae tend to produce better response in soils which are poor.

R. Subrahmanyan; L. L. Relwani; G. B. Manna

1964-01-01

64

Cultivation of nitrogen-fixing blue-green algae on ammonia-depleted effluents from sewage oxidation ponds  

Microsoft Academic Search

The data presented represent an initial, limited attempt on a small scale to cultivate nitrogen-fixing blue-green algae on both chemically defined media and low nitrogen sewage pond effluents. The rates of blue-green algal biomass production were low compared to those of green algae. Nevertheless, it appears that cultivation of nitrogen-fixing blue-green algae is possible on sewage effluents where these algae

J. C. Weissman; D. M. Eisenberg; J. R. Benemann

1978-01-01

65

[Epiphase carotenoids of the blue-green alga Anabaena variabilia].  

PubMed

Epiphase carotenoids were studied in the cells of the obligate phototrophous blue-green alga Anabaena variabilis. Ten pigment zones were detected by column chromatography on alumina and by TLC on cellulose and Silufol UV-254 plates. TLC in the B layer and paper chromatography did not reveal all pigment zones obtained on a column. The data of TLC on cellulose and on Silufol plates confirmed the purity and individual character of the fractions obtained on a column. These data showed also that the pigments obtained upon the separation of the extract on a column were not the products of its interaction with an active adsorbent. Absorption spectra of the isolated pigments were determined in various solvents, and speculations were made concerning the structure of the carotenoids. PMID:408584

Pakhlavuni, I K; Vasil'eva, V E; Gusev, M V

1977-01-01

66

Immunocytochemical Localization of Nitrite Reductase in Green Algae 1  

PubMed Central

The distribution of nitrite reductase (EC 1.7.7.1) in the green algae Chlamydomonas reinhardtii, Monoraphidium braunii, Chlorella fusca, and Scenedesmus obliquus was studied by immunoelectron microscopy. The labeling of ultrathin cryosections was performed with anti-nitrite reductase antibodies followed by gold-labeled goat anti-rabbit antibodies. In C. reinhardtii sections, gold label was mainly associated with the pyrenoid, tonoplast, and plasmalemma. Significant labeling was also detected in the thylakoid region. In all other organisms, label density was lower but distributed in the same locations, except that the plasmalemma of S. obliquus was not significantly labeled. From estimates of the relative volume of different cell regions, we found that approximately 80% of the total enzyme is located in the chloroplastic region (thylakoids plus pyrenoid) of C. reinhardtii, M. braunii, and C. fusca, and 97% in the case of S. obliquus. ImagesFigure 1Figure 2Figure 3Figure 4Figure 5

Lopez-Ruiz, Antonio; Verbelen, Jean-Pierre; Bocanegra, Jose A.; Diez, Jesus

1991-01-01

67

Enhanced Genetic Tools for Engineering Multigene Traits into Green Algae  

PubMed Central

Transgenic microalgae have the potential to impact many diverse biotechnological industries including energy, human and animal nutrition, pharmaceuticals, health and beauty, and specialty chemicals. However, major obstacles to sophisticated genetic and metabolic engineering in algae have been the lack of well-characterized transformation vectors to direct engineered gene products to specific subcellular locations, and the inability to robustly express multiple nuclear-encoded transgenes within a single cell. Here we validate a set of genetic tools that enable protein targeting to distinct subcellular locations, and present two complementary methods for multigene engineering in the eukaryotic green microalga Chlamydomonas reinhardtii. The tools described here will enable advanced metabolic and genetic engineering to promote microalgae biotechnology and product commercialization.

Rasala, Beth A.; Chao, Syh-Shiuan; Pier, Matthew; Barrera, Daniel J.; Mayfield, Stephen P.

2014-01-01

68

Flow cytometric studies of the host-regulated cell cycle in algae symbiotic with green paramecium  

Microsoft Academic Search

Summary. Paramecium bursaria (green paramecium) possesses endosymbiotically growing chlorella-like green algae. An aposymbiotic cell line of P. bursaria (MBw-1) was prepared from the green MB-1 strain with the herbicide paraquat. The SA-2 clone of symbiotic algae was employed to reinfect MBw-1 cells and thus a regreened cell line (MBr-1) was obtained. The regreened paramecia were used to study the impact

T. Kadono; T. Kawano; H. Hosoya; T. Kosaka

2004-01-01

69

Monitoring experiment and analysis of blue-green algae waterbloom in Chaohu Lake by NOAA satellite  

NASA Astrophysics Data System (ADS)

Algal chlorophyll measurement is usually used to assess trophic status of lakes. The development of satellite remote sensing technology make it possible to detect spectral features of algal chlorophyll and to map the spatial distribution of algae in large lakes. In this paper, NOAA satellite data were utilized to monitor the blue-green algae waterbloom in Chaohu Lake, together with the water sampling for concentrations of chlorophhyll-a analysis and spectral measuring simultaneously. The result indicates that: if there are chlorophylls of blue-green algae, the water reflectance in the near infrared band will obviously increase. Based on this spectral characteristic and the features of blue-green algae' float, meteorological satellite NOAA/AVHRR data can be used to monitor the blue-green algae waterbloom in large badly contaminated inland lakes.

Hu, Wen; Yang, Shizhi; Zhai, Wuquan; Zhou, Kun; Huang, Yong

2003-05-01

70

The Cell Walls of Green Algae: A Journey through Evolution and Diversity  

PubMed Central

The green algae represent a large group of morphologically diverse photosynthetic eukaryotes that occupy virtually every photic habitat on the planet. The extracellular coverings of green algae including cell walls are also diverse. A recent surge of research in green algal cell walls fueled by new emerging technologies has revealed new and critical insight concerning these coverings. For example, the late divergent taxa of the Charophycean green algae possess cell walls containing assemblages of polymers with notable similarity to the cellulose, pectins, hemicelluloses, arabinogalactan proteins (AGPs), extensin, and lignin present in embryophyte walls. Ulvophycean seaweeds have cell wall components whose most abundant fibrillar constituents may change from cellulose to ?-mannans to ?-xylans and during different life cycle phases. Likewise, these algae produce complex sulfated polysaccharides, AGPs, and extensin. Chlorophycean green algae produce a wide array of walls ranging from cellulose–pectin complexes to ones made of hydroxyproline-rich glycoproteins. Larger and more detailed surveys of the green algal taxa including incorporation of emerging genomic and transcriptomic data are required in order to more fully resolve evolutionary trends within the green algae and in relationship with higher plants as well as potential applications of wall components in the food and pharmaceutical industries.

Domozych, David S.; Ciancia, Marina; Fangel, Jonatan U.; Mikkelsen, Maria Dalgaard; Ulvskov, Peter; Willats, William G. T.

2012-01-01

71

Slow algae, fast fungi: exceptionally high nucleotide substitution rate differences between lichenized fungi Omphalina and their symbiotic green algae Coccomyxa  

Microsoft Academic Search

Omphalina basidiolichens are obligate mutualistic associations of a fungus of the genus Omphalina (the exhabitant) and a unicellular green alga of the genus Coccomyxa (the inhabitant). It has been suggested that symbiotic inhabitants have a lower rate of genetic change compared to exhabitants because the latter are more exposed to abiotic environmental variation and competition from other organisms. In order

Stefan Zoller; François Lutzoni

2003-01-01

72

The potential for using cyanobacteria (blue-green algae) and algae in the biological control of plant pathogenic bacteria and fungi  

Microsoft Academic Search

Cyanobacteria (blue-green algae) and eukaryote algae occur in freshwater, marine, and terrestrial (soil) habitats. In fact, these microorganisms comprise most of the world's biomass. Although the cyanobacteria are mostly photoautotrophic, some are facultative heterotrophs, capable of growing on certain substrates in darkness. Also, some are non-phototrophic and hence, are obligate heterotrophs. A number of cyanobacteria and eukaryote algae, particularly macroalgae,

Martin M. Kulik

1995-01-01

73

Proton and metal binding capacity of the green freshwater alga Chaetophora elegans  

Microsoft Academic Search

A biomass for removing heavy metal ions from aqueous solutions has been investigated. The green alga Chaetophora elegans was characterized in terms of the number of binding sites and proton binding constant by potentiometric titration in different ionic media. The discrete site distribution model used, considering the algae cells suspensions as a mixture of monoprotic acids, allowed the characterisation of

A. D. Andrade; M. C. E. Rollemberg; J. A. Nóbrega

2005-01-01

74

Assessment of Blue-Green Algae in Substantially Reducing Nitrogen Fertilizer Requirements for Biomass Fuel Crops.  

National Technical Information Service (NTIS)

Laboratory, mass culture, and field studies are being undertaken in order to assess the potential of using blue-green algae (cyanobacteria) as nitrogen biofertilizers on irrigated ground. Of seven candidate strains, two were chosen for application to repl...

D. B. Anderson P. M. Molten B. Metting

1981-01-01

75

Aluminum bioavailability to the green alga Chlorella pyrenoidosa in acidified synthetic soft water  

SciTech Connect

A unicellular green alga, Chlorella pyrenoidosa, was exposed to inorganic Al under controlled experimental conditions to determine whether the biological response elicited by the dissolved metal could be predicted from the free-metal ion concentration, [Al[sup 3+

Parent, L.; Campbell, P.G.C. (Univ. du Quebec, Ste-Foy (Canada))

1994-04-01

76

Life Cycle, Ecology, and Management Considerations of the Green Filamentous Alga, 'Pithophora'.  

National Technical Information Service (NTIS)

Pithophora, a green filamentous, spore-forming alga in the order Cladophorales, forms infestations of thick free-floating mats in small impoundments, shallow lakes, and coves and channels of larger lakes and reservoirs throughout the midwest and southeast...

C. A. Lembi N. L. Pearlmutter D. F. Spencer

1980-01-01

77

Production and release of selenocyanate by different green freshwater algae in environmental and laboratory samples.  

PubMed

In a previous study, selenocyanate was tentatively identified as a biotransformation product when green algae were exposed to environmentally relevant concentrations of selenate. In this follow-up study, we confirm conclusively the presence of selenocyanate in Chlorella vulgaris culture medium by electrospray mass spectrometry, based on selenium's known isotopic pattern. We also demonstrate that the observed phenomenon extends to other green algae (Chlorella kesslerii and Scenedesmus obliquus) and at least one species of blue-green algae (Synechococcus leopoliensis). Further laboratory experiments show that selenocyanate production by algae is enhanced by addition of nitrate, which appears to serve as a source of cyanide produced in the algae. Ultimately, this biotransformation process was confirmed in field experiments where trace amounts of selenocyanate (0.215 ± 0.010 ppb) were observed in a eutrophic, selenium-impacted river with massive algal blooms, which consisted of filamentous green algae (Cladophora genus) and blue-green algae (Anabaena genus). Selenocyanate abundance was low despite elevated selenium concentrations, apparently due to suppression of selenate uptake by sulfate, and insufficient nitrogen concentrations. Finally, trace levels of several other unidentified selenium-containing compounds were observed in these river water samples; preliminary suggestions for their identities include thioselenate and small organic Se species. PMID:22455319

LeBlanc, Kelly L; Smith, Matthew S; Wallschläger, Dirk

2012-06-01

78

Isolation and characterization of phycocyanins from the blue-green alga Spirulina platensis  

Microsoft Academic Search

Two main biliproteins c-phycocyanin and allophycocyanin were identified and characterized in the blue-green alga Spirulina platensis. The specific absorbance, fluorescence maxima, sub-unit make-up and amino acid composition of the biliproteins in Spirulina platensis resemble those reported for other blue-green algae. However, the minimum molecular weights (44,000 for c-phycocyanin and 38,000 for the allophycocyanin) and the specific extinction coefficients (73, and

Samy Boussiba; Amos E. Richmond

1979-01-01

79

Intracellular ?-Carbonic Anhydrase of the Unicellular Green Alga Coccomyxa1  

PubMed Central

Carbonic anhydrase (CA) (EC 4.2.1.1) enzymes catalyze the reversible hydration of CO2, a reaction that is important in many physiological processes. We have cloned and sequenced a full-length cDNA encoding an intracellular ?-CA from the unicellular green alga Coccomyxa. Nucleotide sequence data show that the isolated cDNA contains an open reading frame encoding a polypeptide of 227 amino acids. The predicted polypeptide is similar to ?-type CAs from Escherichia coli and higher plants, with an identity of 26% to 30%. The Coccomyxa cDNA was overexpressed in E. coli, and the enzyme was purified and biochemically characterized. The mature protein is a homotetramer with an estimated molecular mass of 100 kD. The CO2-hydration activity of the Coccomyxa enzyme is comparable with that of the pea homolog. However, the activity of Coccomyxa CA is largely insensitive to oxidative conditions, in contrast to similar enzymes from most higher plants. Fractionation studies further showed that Coccomyxa CA is extrachloroplastic.

Hiltonen, Thomas; Bjorkbacka, Harry; Forsman, Cecilia; Clarke, Adrian K.; Samuelsson, Goran

1998-01-01

80

Production of carbonate sediments by a unicellular green alga  

USGS Publications Warehouse

This study investigates the ability of the unicellular green alga Natmochloris atoimis to precipitate CaCO3, quantifies mineral precipitation rates, estimates sediment production in a N. atomiis bloom, and discusses the implications of microbial calcification for carbonate sediment deposition. A series of N. atomus cultures, isolated from Lake Reeve, Australia, were incubated at various pH and calcium concentrations to determine environmental parameters for calcification. Rates of calcification were calculated from initial and postincubation alkalinity, pH, and calcium measurements. Replicate experiments and controls consisting of non-calcifying cultures, uninoculated media, and dead cell cultures were performed using environmental culture parameters determined in series cultures. Average calcification rates from replicate experiments were used to predict daily sediment production rates in a small bloom of N. atomus. N. atomus precipitates 0.138 g/L of calcite in approximately 4 h when incubated at pH 8.5, 14.24 mM calcium concentration, 33 ??C, 100 ??E/m2/s light intensity, and a cell population density of 107 cells/mL. Assuming continuous precipitation, this corresponds to a maximum estimated sediment production rate of 1.6 ?? 106 kg of CaCO3, per 12 h day in a single bloom of 3.2 ?? 109 L. Our results suggest that microbial calcification contributes significantly to the carbonate sediment budget.

Yates, K. K.; Robbins, L. L.

1998-01-01

81

Combined toxicity of pesticide mixtures on green algae and photobacteria.  

PubMed

Different organisms have diverse responses to the same chemicals or mixtures. In this paper, we selected the green algae Chlorella pyrenoidosa (C. pyrenoidosa) and photobacteria Vibrio qinghaiensis sp.-Q67 (V. qinghaiensis) as target organisms and determined the toxicities of six pesticides, including three herbicides (simetryn, bromacil and hexazinone), two fungicides (dodine and metalaxyl) and one insecticide (propoxur), and their mixtures by using the microplate toxicity analysis. The toxicities of three herbicides to C. pyrenoidosa are much higher than those to V. qinghaiensis, and the toxicities of metalaxyl and propoxur to V. qinghaiensis are higher than those to C. pyrenoidosa, while the toxicity of dodine to C. pyrenoidosa is similar to those to V. qinghaiensis. Using the concentration addition as an additive reference model, the binary pesticide mixtures exhibited different toxicity interactions, i.e., displayed antagonism to C. pyrenoidosa but synergism to V. qinghaiensis. However, the toxicities of the multi-component mixtures of more than two components are additive and can be predicted by the concentration addition model. PMID:23816361

Liu, Shu-Shen; Wang, Cheng-Lin; Zhang, Jin; Zhu, Xiang-Wei; Li, Wei-Ying

2013-09-01

82

Phylogenetic and molecular analysis of hydrogen-producing green algae  

PubMed Central

A select set of microalgae are reported to be able to catalyse photobiological H2 production from water. Based on the model organism Chlamydomonas reinhardtii, a method was developed for the screening of naturally occurring H2-producing microalgae. By purging algal cultures with N2 in the dark and subsequent illumination, it is possible to rapidly induce photobiological H2 evolution. Using NMR spectroscopy for metabolic profiling in C. reinhardtii, acetate, formate, and ethanol were found to be key compounds contributing to metabolic variance during the assay. This procedure can be used to test algal species existing as axenic or mixed cultures for their ability to produce H2. Using this system, five algal isolates capable of H2 production were identified in various aquatic systems. A phylogenetic tree was constructed using ribosomal sequence data of green unicellular algae to determine if there were taxonomic patterns of H2 production. H2-producing algal species were seen to be dispersed amongst most clades, indicating an H2-producing capacity preceded evolution of the phylum Chlorophyta.

Timmins, Matthew; Thomas-Hall, Skye R.; Darling, Aaron; Zhang, Eugene; Hankamer, Ben; Marx, Ute C.; Schenk, Peer M.

2009-01-01

83

Horizontal distribution of planktonic diatoms in Green Bay, mid-July 1970  

Microsoft Academic Search

A synoptic survey of Green Bay was undertaken in mid-July 1970 to dcterminc the hori- zontal distribution of major species of planktonic diatoms. Principal component analysts of R-correlation and covariance matrices, and four methods of factor analysis described a general bipolar axis which grouped MeZosiru grunulata, Steph- anodiscus spp., Cyclotella meneghiniana, and Stephanodiscus niagarae at one pole and Fragilaria crotonensis,

RUTH E. HOLLAND; LARRY W. CLAFLIN

1975-01-01

84

Form I Rubiscos from non-green algae are expressed abundantly but not assembled in tobacco chloroplasts.  

PubMed

Non-green algae have Rubiscos that are phylogenetically distinct from their counterparts in green algae and higher plants. Some non-green-algal Rubiscos are more specific for CO2, relative to O2, than higher-plant Rubiscos, sometimes coupled with lower Michaelis constants for CO2. If these Rubiscos could be substituted for the higher-plant enzyme, and if they functioned successfully in the higher-plant chloroplast and were regulated appropriately, they would improve the CO2 use and quantum efficiency of higher-plant photosynthesis. To assess the feasibility of expressing non-green algal Rubiscos in higher-plant chloroplasts, we inserted the rbcLS operons from the rhodophyte Galdieria sulphuraria and the diatom Phaeodactylum tricornutum into the inverted repeats of the plastid genome of tobacco, leaving the tobacco rbcL gene unaltered. Homoplasmic transformants were selected. The transgenes directed the synthesis of abundant amounts of transcripts and both subunits of the foreign Rubiscos. In some circumstances, leaves of the transformants with the P. tricornutum Rubisco contained as much foreign Rubisco protein as endogenous tobacco Rubisco (>30% of the soluble leaf protein). However, the subunits of the foreign Rubiscos were not properly folded and/or assembled. All the foreign large subunits and most of the foreign small subunits were recovered in the insoluble fractions of leaf extracts. Edman sequencing yielded the expected N-terminal sequences for the foreign small subunits but the N-termini of the foreign large subunits were blocked. Accumulation of large amounts of denatured foreign Rubisco in the leaves, particularly of the P. tricornutum transformants, caused a reduction in the amount of tobacco Rubisco present, with concomitant reductions in leaf CO2 assimilation and plant growth. PMID:11439139

Whitney, S M; Baldet, P; Hudson, G S; Andrews, T J

2001-06-01

85

Chloroplast gene arrangement variation within a closely related group of green algae (Trebouxiophyceae, Chlorophyta).  

PubMed

The 22 published chloroplast genomes of green algae, representing sparse taxonomic sampling of diverse lineages that span over one billion years of evolution, each possess a unique gene arrangement. In contrast, many of the >190 published embryophyte (land plant) chloroplast genomes have relatively conserved architectures. To determine the phylogenetic depth at which chloroplast gene rearrangements occur in green algae, a 1.5-4 kb segment of the chloroplast genome was compared across nine species in three closely related genera of Trebouxiophyceae (Chlorophyta). In total, four distinct gene arrangements were obtained for the three genera Elliptochloris, Hemichloris, and Coccomyxa. In Elliptochloris, three distinct chloroplast gene arrangements were detected, one of which is shared with members of its sister genus Hemichloris. Both species of Coccomyxa examined share the fourth arrangement of this genome region, one characterized by very long spacers. Next, the order of genes found in this segment of the chloroplast genome was compared across green algae and land plants. As taxonomic ranks are not equivalent among different groups of organisms, the maximum molecular divergence among taxa sharing a common gene arrangement in this genome segment was compared. Well-supported clades possessing a single gene order had similar phylogenetic depth in green algae and embryophytes. When the dominant gene order of this chloroplast segment in embryophytes was assumed to be ancestral for land plants, the maximum molecular divergence was found to be over two times greater in embryophytes than in trebouxiophyte green algae. This study greatly expands information about chloroplast genome variation in green algae, is the first to demonstrate such variation among congeneric green algae, and further illustrates the fluidity of green algal chloroplast genome architecture in comparison to that of many embryophytes. PMID:22659018

Letsch, Molly R; Lewis, Louise A

2012-09-01

86

Partial sequences of 16S rRNA and the phylogeny of blue-green algae and chloroplasts  

Microsoft Academic Search

Partial sequence analyses of 16S ribosomal RNAs of blue-green algae and chloroplasts reveal that blue-green algae are typically prokaryotic and related to the bacilli, that red algal chloroplasts are probably of blue-green algal origin, and that euglenoid and red algal chloroplasts may have arisen independently.

L. Bonen; W. F. Doolittle

1976-01-01

87

Hidden genetic diversity in the green alga Spirogyra (Zygnematophyceae, Streptophyta)  

PubMed Central

Background The unbranched filamentous green alga Spirogyra (Streptophyta, Zygnemataceae) is easily recognizable based on its vegetative morphology, which shows one to several spiral chloroplasts. This simple structure falsely points to a low genetic diversity: Spirogyra is commonly excluded from phylogenetic analyses because the genus is known as a long-branch taxon caused by a high evolutionary rate. Results We focused on this genetic diversity and sequenced 130 Spirogyra small subunit nuclear ribosomal DNA (SSU rDNA) strands of different origin. The resulting SSU rDNA sequences were used for phylogenetic analyses using complex evolutionary models (posterior probability, maximum likelihood, neighbor joining, and maximum parsimony methods). The sequences were between 1672 and 1779 nucleotides long. Sequence comparisons revealed 53 individual clones, but our results still support monophyly of the genus. Our data set did not contain a single slow-evolving taxon that would have been placed on a shorter branch compared to the remaining sequences. Out of 130 accessions analyzed, 72 showed a secondary loss of the 1506 group I intron, which formed a long-branched group within the genus. The phylogenetic relationship to the genus Spirotaenia was not resolved satisfactorily. The genetic distance within the genus Spirogyra exceeded the distances measured within any other genus of the remaining Zygnemataceae included in this study. Conclusion Overall, we define eight distinct clades of Spirogyra, one of them including the genus Sirogonium. A large number of non-homoplasious synapomorphies (NHS; 114 NHS in total) was found for Spirogyra (41 NHS) and for each clade (totaling 73 NHS). This emphasizes the high genetic diversity of this genus and the distance to the remaining Zygnematophyceae.

2012-01-01

88

Adsorption of malachite green onto Pithophora sp., a fresh water algae: Equilibrium and kinetic modelling  

Microsoft Academic Search

Batch biosorption experiments were carried out for the removal of malachite green a cationic dye from its aqueous solution using raw and thermally activated Pithophora sp., a fresh water algae as biosorbent. The operating variables studied are initial malachite green concentration, biomass concentration and solution pH. Pithophora sp. activated at 300°C for 50min posses a maximum sorption capacity for the

K. Vasanth Kumar; S. Sivanesan; V. Ramamurthi

2005-01-01

89

Tracing floating green algae blooms in the Yellow Sea and the East China Sea using Lagrangian transport simulations  

NASA Astrophysics Data System (ADS)

Lagrangian particle tracking experiments were conducted to understand the pathway of the floating green algae patches observed in the Yellow Sea (YS) and East China Sea (ECS) in summer 2011. The numerical simulation results indicated that dominant southerly winds during June and July 2011 were related to offshore movement of the floating green algae, especially their eastward extension in the YS/ECS. An infrequent and unusual event occurred in June 2011: a severe Tropical Strom MEARI, caused the green algae to detach from the coast and initiated movement to the east. After the typhoon event, sea surface temperature recovered rapidly enough to grow the floating green algae, and wind and local current controlled the movement of the massive floating algae patches (coastal accumulation or offshore advection in the area). Analysis of the floating green algae movement using satellite images during passage of Typhoon MAON in July 2011 revealed that the floating green algae patches were significantly controlled by both ocean currents and enhanced winds. These findings suggest that the floating green algae bloom off Qingdao, China and in the middle of the YS and ECS in the summer of 2011 occurred due to the combined effects of recent rapid expansion of seaweed aquaculture, strong winds, and the wind patterns in blooming regions. Our combined approach, using satellite data and numerical simulations, provides a robust estimate for tracing and monitoring changes in green algae blooms on a regional scale.

Park, Young-Gyu; Son, Young Baek; Choi, Byoung-Ju; Kim, Yong Hoon

2014-05-01

90

A cryptic intracellular green alga in Ginkgo biloba : ribosomal DNA markers reveal worldwide distribution  

Microsoft Academic Search

Intracellular symbioses involving eukaryotic microalgae and a variety of heterotrophic protists and invertebrates are widespread,\\u000a but are unknown in higher plants. Recently, we reported the isolation and molecular identification of a Coccomyxa-like green alga from in vitro cell cultures of Ginkgo biloba L. This alga resides intracellularly in an immature “precursor” form with a nonfunctional chloroplast, implying that algal\\u000a photosynthetic

Jocelyne Trémouillaux-Guiller; Volker A. R. Huss

2007-01-01

91

Hyperaccumulation of astaxanthin in a green alga Haematococcus pluvialis at elevated temperatures  

Microsoft Academic Search

Summary When a green algaHaematococcus pluvialis was cultivated at 30°C, astaxanthin production was 3-fold more increased than at 20°C. With acetate supplementation to 30°C culture, the alga synthesized over 2-fold more carotenoid than without addition. Tiron, a radical scavenger, however, severely blocked the stimulated carotenogenesis, suggesting that endogenously generated active oxygen was responsible for the highly stimulated carotenogenesis. From these

Agus Eko Tjahjono; Yachiyo Hayama; Toshihide Kakizono; Yoshio Terada; Naomichi Nishio; Shiro Nagai

1994-01-01

92

EFFECTS OF ZIRCONIUM ON THE GROWTH AND PHOTOSYNTHETIC PIGMENT COMPOSITION OF CHLORELLA PYRENOIDOSA GREEN ALGAE  

Microsoft Academic Search

The effects of zirconium (Zr) were investigated on the growth rate, dry matter accumulation, and elemental and photosynthetic pigment composition of Chlorella pyrenoidosa green algae. Algae were treated with 0.1–50 ?M (? 0.009–4.561 mg dm) of Zr; inorganic compounds (Zr oxychloride, Zr nitrate) and organic chelates (Zr ascorbate or Zr citrate) were applied. All Zr compounds displayed only a slight

László Simon; Marietta Fodor; István Pais

2001-01-01

93

AlgaePath: comprehensive analysis of metabolic pathways using transcript abundance data from next-generation sequencing in green algae  

PubMed Central

Background Algae are important non-vascular plants that have many research applications, including high species diversity, biofuel sources, and adsorption of heavy metals and, following processing, are used as ingredients in health supplements. The increasing availability of next-generation sequencing (NGS) data for algae genomes and transcriptomes has made the development of an integrated resource for retrieving gene expression data and metabolic pathway essential for functional analysis and systems biology. In a currently available resource, gene expression profiles and biological pathways are displayed separately, making it impossible to easily search current databases to identify the cellular response mechanisms. Therefore, in this work the novel AlgaePath database was developed to retrieve transcript abundance profiles efficiently under various conditions in numerous metabolic pathways. Description AlgaePath is a web-based database that integrates gene information, biological pathways, and NGS datasets for the green algae Chlamydomonas reinhardtii and Neodesmus sp. UTEX 2219–4. Users can search this database to identify transcript abundance profiles and pathway information using five query pages (Gene Search, Pathway Search, Differentially Expressed Genes (DEGs) Search, Gene Group Analysis, and Co-expression Analysis). The transcript abundance data of 45 and four samples from C. reinhardtii and Neodesmus sp. UTEX 2219–4, respectively, can be obtained directly on pathway maps. Genes that are differentially expressed between two conditions can be identified using Folds Search. The Gene Group Analysis page includes a pathway enrichment analysis, and can be used to easily compare the transcript abundance profiles of functionally related genes on a map. Finally, the Co-expression Analysis page can be used to search for co-expressed transcripts of a target gene. The results of the searches will provide a valuable reference for designing further experiments and for elucidating critical mechanisms from high-throughput data. Conclusions AlgaePath is an effective interface that can be used to clarify the transcript response mechanisms in different metabolic pathways under various conditions. Importantly, AlgaePath can be mined to identify critical mechanisms based on high-throughput sequencing. To our knowledge, AlgaePath is the most comprehensive resource for integrating numerous databases and analysis tools in algae. The system can be accessed freely online at http://algaepath.itps.ncku.edu.tw.

2014-01-01

94

Effects of monomethylhydrazine on selected species of marine diatoms  

SciTech Connect

A safe concentration (SC) and the mean effective concentration (EC) for hydrazine, MMH, and unsymmetrical dimethylhydrazine have been determined on species of green algae. The aqueous degradation of MMH is relatively rapid compared to the time green algae require to reach maximum standing crop. The diatoms Thalassiosira pseudonana and Skeletonema costatum reach maximum standing crop in 6 to 7 days in culture which makes them ideal for testing short-term effects of MMH. The objectives of this study were to determine the relative sensitivity of selected marine diatoms to MMH and whether species composition would be affected by MMH.

Wendler, B.W.; Norris, D.R.

1985-07-01

95

[Conservative motif CMLD in silicic acid transport proteins of diatom algae].  

PubMed

Sequencing of fragments of genes coding for silicic acid transport (SIT) proteins of diatoms of evolutionary distant classes (centric Chaetoceros muelleri Lemmermann, pennate araphid Synedra acus Kützing, pennate raphid Phaeodactylum tricornutum Bohlin, and pennate with keeled raphe system Cylindrotheca fusiformis Reimann et Lewin), revealed the presence in these proteins of a conservative amino acid motif CMLD. Hydropathy profiles suggest that CMLD occupies a position between two transmembrane strands which do not contain lysine and arginine residues. The two strands are good candidates for the role of the channel along which transport of silicic acid occurs. CMLD is a rare motif. Diatoms are known to need Zn2+ for the incorporation of silica. Presumably, CMLD is the site of Zn2+ binding of SITs. We found that the growth of diatoms is inhibited by a negatively charged alkylating reagent 5-(2-iodoacetamidoethyl)aminonaphtalene-1-sulfonic acid which cannot penetrate through the cell membrane. Cysteine of CMLD can be a target of this reagent. Synthetic peptide NCMLDY forms a complex with Zn2+, as revealed by the fact that the ion considerably reduces the rate of alkylation of the peptide. PMID:15856954

Shcherbakova, T A; Masiukova, Iu A; Safonova, T A; Petrova, D P; Vereshchagin, A L; Minaeva, T V; Adel'shin, R V; Tribo?, T I; Stonik, I V; A?zda?cher, N A; Kozlov, M V; Likhoshva?, E V; Grachev, M A

2005-01-01

96

The Protein Quality of Waste-grown Green Algae I. QUALITY OF PROTEIN IN MIXTURES OF ALGAE, NONFAT POWDERED MILK, AND CEREALS1  

Microsoft Academic Search

The protein efficiency ratio (PER) was determined, as a measure of protein quality, on thick gruels and on baked products containing waste-grown green algae, a mixture of Scenedesmus quadricauda and Chlorella, spp., at a ratio of 10:1. Algae-cereal-nonfat dry milk mixtures (the algae and cereals boiled for 30 minutes to make a thick gruel) and milk added to the cooked

BESSIE B. COOK; ESTHER W. LAU; ANDBETTY M. BAILEY

97

Isolation of plasmid from the blue-green alga Spirulina platensis  

NASA Astrophysics Data System (ADS)

CCC plasmid was isolated from an economically important blue-green alga — Spirulina platensis (1.7×106 dalton from the S6 strain and 1.2×106 dalton from the F3 strain) using a rapid method based on ultrasonic disruption of algal cells and alkaline removal of chromosomal DNA. The difference in the molecular weight of the CCC DNAs from the two strains differing in form suggests that plasmid may be related with the differentiation of algal form. This modified method, which does not use any lysozyme, is a quick and effective method of plasmid isolation, especially for filamentous blue-green algae.

Qin, Song; Tong, Shun; Zhang, Peijun; Tseng, C. K.

1993-09-01

98

The rapid quantitation of the filamentous blue-green alga plectonema boryanum by the luciferase assay for ATP  

NASA Technical Reports Server (NTRS)

Plectonema boryanum is a filamentous blue green alga. Blue green algae have a procaryotic cellular organization similar to bacteria, but are usually obligate photoautotrophs, obtaining their carbon and energy from photosynthetic mechanism similar to higher plants. This research deals with a comparison of three methods of quantitating filamentous populations: microscopic cell counts, the luciferase assay for ATP and optical density measurements.

Bush, V. N.

1974-01-01

99

The effect of chloramphenicol on the production of cyanophycin granule polypeptide in the blue-green alga Anabaena cylindrica  

Microsoft Academic Search

The cyanophycin or structured granule of the blue-green algae is composed of polypeptides which are copolymers of aspartic acid and arginine. The addition of chloramphenicol to an exponentially growing culture of the blue-green alga Anabaena cylindrica at concentrations which completely inhibit protein synthesis results both in the inhibition of growth and in the accumulation of the cyanophycin granule polypeptide (CGP).

Robert D. Simon

1973-01-01

100

ASPECTS OF PHOSPHATE UTILIZATION BY BLUE-GREEN ALGAE  

EPA Science Inventory

The effects of various external phosphate concentrations on physiological and cytological aspects of Plectonema boryanum have been studied. P. boryanum was found to tolerate a wide range of phosphate concentrations, from 1 to 1000 mg of phosphate per liter. Growth of the alga in ...

101

Toxicity of paraquat to a green alga scenedesmus acutus  

Microsoft Academic Search

An algal toxicity test was conducted to evaluate the toxic effects on a freshwater alga of increasing concentrations of the herbicide paraquat upon growth, chlorophyll and protein content. Paraquat, a widely used herbicide, was found highly toxic to Scenedesmus acutus. Growth pattern, as well as growth rates and generation times exhibited by the cultures exposed up to 0.05 mg Pq\\/L,

María Elena Sáenz; Juan Accorinti; María del Carmen Tortorelli

1993-01-01

102

Resurrection kinetics of photosynthesis in desiccation-tolerant terrestrial green algae (Chlorophyta) on tree bark.  

PubMed

The rough bark of orchard trees (Malus) around Darmstadt is predominantly covered in red to purple-brown layers (biofilms) of epiphytic terrestrial alga of Trentepohlia umbrina. The smooth bark of forest trees (Fagus sylvatica L. and Acer sp.) in the same area is covered by bright green biofilms composed of the green algae Desmococcus, Apatococcus and Trebouxia, with a few cells of Coccomyxa and 'Chlorella' trebouxioides between them. These algae are desiccation tolerant. After samples of bark with the biofilms were kept in dry air in darkness for various periods of time, potential quantum yield of PSII, F(v)/F(m), recovered during rehydration upon rewetting. The kinetics and degree of recovery depended on the length of time that the algae were kept in dry air in the desiccated state. Recovery was better for green biofilm samples, i.e. quite good even after 80 days of desiccation (F(v)/F(m) = ca. 50% of initial value), than the red samples, where recovery was only adequate up to ca. 30-40 days of desiccation (F(v)/F(m) = ca. 20-55% of initial value). It is concluded that the different bark types constitute different ecophysiological niches that can be occupied by the algae and that can be distinguished by their capacity to recover from desiccation after different times in the dry state. PMID:20522179

Lüttge, U; Büdel, B

2010-05-01

103

Desiccation stress and tolerance in green algae: consequences for ultrastructure, physiological and molecular mechanisms  

PubMed Central

Although most green algae typically occur in aquatic ecosystems, many species also live partly or permanently under aeroterrestrial conditions, where the cells are exposed to the atmosphere and hence regularly experience dehydration. The ability of algal cells to survive in an air-dried state is termed desiccation tolerance. The mechanisms involved in desiccation tolerance of green algae are still poorly understood, and hence the aim of this review is to summarize recent findings on the effects of desiccation and osmotic water loss. Starting from structural changes, physiological, and biochemical consequences of desiccation will be addressed in different green-algal lineages. The available data clearly indicate a range of strategies, which are rather different in streptophycean and non-streptophycean green algae. While members of the Trebouxiophyceae exhibit effective water loss-prevention mechanisms based on the biosynthesis and accumulation of particular organic osmolytes such as polyols, these compounds are so far not reported in representatives of the Streptophyta. In members of the Streptophyta such as Klebsormidium, the most striking observation is the appearance of cross-walls in desiccated samples, which are strongly undulating, suggesting a high degree of mechanical flexibility. This aids in maintaining structural integrity in the dried state and allows the cell to maintain turgor pressure for a prolonged period of time during the dehydration process. Physiological strategies in aeroterrestrial green algae generally include a rapid reduction of photosynthesis during desiccation, but also a rather quick recovery after rewetting, whereas aquatic species are sensitive to drying. The underlying mechanisms such as the affected molecular components of the photosynthetic machinery are poorly understood in green algae. Therefore, modern approaches based on transcriptomics, proteomics, and/or metabolomics are urgently needed to better understand the molecular mechanisms involved in desiccation-stress physiology of these organisms. The very limited existing information is described in the present review.

Holzinger, Andreas; Karsten, Ulf

2013-01-01

104

Isolation and Purification of Intact Gas Vesicles from a Blue-Green Alga  

Microsoft Academic Search

THE gas vesicles which make up the gas vacuoles of blue-green algae collapse flat on application of a few atmospheres pressure1 and this frustrates attempts to isolate them intact by methods of cell rupture and centrifugation used in obtaining preparations of other subcellular organelles2. We describe here a novel method of lysing blue-green algal cells, the isolation of their intact

A. E. Walsby; Barbara Buckland

1969-01-01

105

Hydrogen production by a thermophilic blue-green alga Mastigocladus laminosus  

NASA Astrophysics Data System (ADS)

Light-driven hydrogen evolution by a thermophilic blue-green alga, Mastigocladus laminosus, was demonstrated and characterized under nitrogen-starved conditions. Air-grown cultures of this alga evolved hydrogen under Ar/CO2 at rates up to 2.2 ml/mg chl/hr. The optimum temperature and pH for the hydrogen evolution were 44-49 C and pH 7.0-7.5, respectively. Evolution in light was depressed by N2 gas and inhibited by salicylaldoxime or 2,4-dinitrophenol, indicating that nitrogenase was mainly responsible for the hydrogen evolution. The evolution rate was improved by adding carbon monoxide and acetylene to the gas phase of Ar/CO2. In addition, photobiological production of hydrogen (biophotolysis) by various blue-green algae is briefly reviewed and discussed.

Miura, Y.; Yokoyama, H.; Miyamoto, K.; Okazaki, M.; Komemushi, S.

106

Dopamine release by the green alga Ulvaria obscura after simulated immersion by incoming tides  

Microsoft Academic Search

Ulvaria obscura, a prominent component of green tide blooms in Washington, is unique among macroalgae because it contains dopamine. To examine dopamine release by U. obscura following simulated low tides, we conducted 6 field experiments in which algae were emersed for 75 min and then immersed in filtered seawater (FSW). Dopamine was measured in algal tissues prior to emersion and 3 h

Kathryn L. Van Alstyne; Katie J. Anderson; Amanda K. Winans; Sue-Ann Gifford

2011-01-01

107

The Influence of Simazine on the Photosynthetic Pigments of Green Algae.  

National Technical Information Service (NTIS)

The amounts of chlorophylls a and b, carotin, lutein and violaxanthin and the chlorophyll luminescence spectra were determined after the incubation for 2, 7 and 17 days of three species of green algae in a medium which either did or did not contain simazi...

L. N. Paromenskeya

1972-01-01

108

Endolithic Blue-Green Algae in the Dry Valleys: Primary Producers in the Antarctic Desert Ecosystem  

Microsoft Academic Search

Endolithic unicellular blue-green algae occur under the surface of orthoquartzite rocks in the dry valleys of southern Victoria Land, Antarctica. This report of primary producers in the Antarctic desert ecosystem suggests that, in future efforts to detect life in extraterrestrial (for example, martian) environments, scientists should consider the possible existence of endolithic life forms.

E. Imre Friedmann; Roseli Ocampo

1976-01-01

109

Simulation of gamete behaviors and the evolution of anisogamy: reproductive strategies of marine green algae  

Microsoft Academic Search

In marine green algae, isogamous or slightly anisogamous species are taxonomically widespread. They produce positively phototactic gametes in both sexes. We developed a new numerical simulator of gamete behavior using C++ and pseudo-parallelization methods to elucidate potential advantages of phototaxis. Input parameters were set based on experimental data. Each gamete swimming in a virtual rectangular test tank was tracked and

Tatsuya TOGASHI; John L. BARTELT; Paul Alan COX

2004-01-01

110

A STATUS REPORT ON PLANKTONIC CYANOBACTERIA (BLUE-GREEN ALGAE) AND THEIR TOXINS  

EPA Science Inventory

Toxic blue-green algae (cyanobacteria) continue to be agents of certain waterbased toxicoses. heir presence is now being acknowledged in many of the world's fresh and brackish waters with eutrophication status of meso to hypereutrophic. ense surface scums called waterblooms will ...

111

Fine structure of developing polyphosphate bodies in a blue-green alga, Plectonema boryanum  

Microsoft Academic Search

Stages in the development of polyphosphate bodies in the blue-green alga, Plectonema boryanum, grown under continuous illumination in the presence of excess phosphate, are reported. During the first stage, an electronlucent area appears near the nucleoplasm or cross walls; it gradually increases to a size approximately equal to that of the final polyphosphate body. In this area a porous structure

Thomas E. Jensen

1969-01-01

112

Fatty acid composition and physiological properties of some filamentous blue-green algae  

Microsoft Academic Search

The fatty acids of 32 axenic strains of filamentous blue-green algae have been analyzed. As an aid to the interpretation of the results, the strains have been assigned to provisional typological groups based upon their morphology and certain physiological characters. The latter are the ability to grow heterotrophically in the dark with glucose as carbon and energy source, the ability

C. N. Kenyon; R. Rippka; R. Y. Stanier

1972-01-01

113

Influence of light on chlorophyll. A content of blue-green algae treated with heavy metals  

SciTech Connect

The toxicity of heavy metals is manifested in multifarious forms. Factors like illumination influence the inhibitory effect of heavy metals on chlorophyll metabolism and photosynthetic activities. The present study was undertaken to explore the effect of light on the chlorophyll A (Chl A) content of blue green algae. This is in continuation of heavy metal toxicity and accumulation studies on cyanobacteria reported earlier.

Azeez, P.A.; Banerjee, D.K.

1987-06-01

114

The utilization of molecular hydrogen by the blue-green alga Anabaena cylindrica  

Microsoft Academic Search

The blue-green alga Anabaena cylindrica is found to consume molecular hydrogen in a hydrogenase dependent reaction. This hydrogen uptake proceeds in the dark and is strictly dependent on oxygen, thus representing a Knallgas reactions. Its rate is almost as high as that of the endogenous respiration in Anabaena. Studies with inhibitors reveal that hydrogen is utilized via the complete respiratory

H. Bothe; J. Tennigkeit; G. Eisbrenner

1977-01-01

115

Evidence for genetic transformation in blue-green alga Anacystis nidulans  

Microsoft Academic Search

Evidence has been presented that blue-green alga Anacystic nidulans can undergo genetic transformation. DNA from erythromycin-, streptomycin-resistant of filamentous strains has been found to transform appropriate markers to a wild type or some other recipients. Favourable conditions for transformation have been described with respect to the revealing of transformants, the concentration of DNA and the competence of cells.

S. V. Shestakov; Nguyen Than Khyen

1970-01-01

116

The Photoassimilation of Organic Compounds by Autotrophic Blue-green Algae  

Microsoft Academic Search

SUMMARY Four obligately photoautotrophic blue-green algae were shown to assimi- late acetate. This reaction was light dependent and was greatly decreased in the absence of carbon dioxide. Acetate was incorporated mainly into the ethanol extractable (lipid) fraction of the organisms and into the protein fraction. Only four amino acids (glutamate, proline, arginine, leucine) were significantly radioactive as a result of

D. S. Hoare; S. L. Hoare; R. B. Moore

1967-01-01

117

Toxicity and binding of copper, zinc, and cadmium by the blue-green alga, Chroococcus paris  

Microsoft Academic Search

The toxic effects and accumulation of the heavy metals, Cd, Cu, and Zn by the sheath forming blue-green alga Chroococcus paris were investigated. All three of the metals were bound rapidly. Approximately 90% of the total amount of the added metal was bound within 1 min. Further significant binding occurred at a slower rate. The maximum metal binding capacity, as

Albin Les; Robert W. Walker

1984-01-01

118

Ultrastructure of the flagellar apparatus of the green alga Tetraselmis subcordiformis  

Microsoft Academic Search

Summary The ultrastructure of the flagellar apparatus of the marine quadriflagellate green algaTetraselmis subcordiformis is described in detail. Special consideration is given to the functional significance of the contractile rhizoplast and also to a complex structure which anchors the flagellar apparatus to the cell membrane and theca. The flagellar apparatus lies at the base of a deep apical depression. Four

J. L. Salisbury; J. A. Swanson; G. L. Floyd; R. Hall; Nita J. Maihle

1981-01-01

119

Chemical induction of colony formation in a green alga (Scenedesmus acutus) by grazers (Daphnia)  

Microsoft Academic Search

The green alga, Scenedesmus acutus, grows in culture in unicellular form, but it forms colonies (coenobia) when exposed for 48 h to a chemical released by the grazer Daphnia magna. The colony-forming response can be evoked only in growing cells. The Daphnia factor affects colony size but not algal growth rate. The minimum concentration of Daphnia factor that induces colony

WINFRIED LAMPERT; KARL OTTO ROTHHAUPT; ERIC VON ELERT

1994-01-01

120

The Influence of Simazine on the Photosynthetic Pigments of Green Algae.  

National Technical Information Service (NTIS)

The amount of chlorophylls a and b, carotin, lutein and violaxanthin and the chlorophyll luminescence spectra were determined after the incubation for 2, 7 and 17 days of three species of green algae in a medium which either contained or did not contain t...

L. N. Paromenskeya G. N. Lyalin

1972-01-01

121

THE FINE STRUCTURE OF THE NUCLEAR MATERIAL OF A BLUE-GREEN ALGA, ANABAENA CYLINDRICA LEMM  

Microsoft Academic Search

The chromatinic material of the blue-green alga Anabaena cylindrica has complex configura- tions in the central regions of the cells. The distribution of the chromatin within the cells varies in different filaments, probably in response to variations in the disposition of other cellular components. In electron micrographs of thin sections of organisms fixed by the method of Kellenberger, Ryter, and

DAVID A. HOPWOOD; AUDREY M. GLAUERT

1960-01-01

122

Morphological changes in the life cycle of the green alga Haematococcus pluvialis  

Microsoft Academic Search

A 2-week model life cycle of the green alga Haematococcus pluvialis was constructed, consisting of four cell stages: vegetative cell growth, encystment, maturation, and germination. Each algal cell stage could be distinguished by the ratio of pigments (carotenoid\\/chlorophyll) and the intracellular protein content. Using the culture system developed, light was shown to be essential for both carotenogenesis and cell differentiation

Makio Kobayashi; Yoshiro Kurimura; Toshihide Kakizono; Naomichi Nishio; Yasunobu Tsuji

1997-01-01

123

Isoprenoid biosynthesis authenticates the classification of the green alga Mesostigma viride as an ancient streptophyte.  

PubMed

Land plants harbor two essential and completely different metabolic pathways for isoprenoid synthesis. The cytosolic mevalonate pathway (MVA) is shared with heterotrophic eukaryotes, whereas the plastidial 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway has a cyanobacterial origin and was recruited after primary endosymbiosis. Terrestrial plants and green algae have a common evolutionary ancestry, but biochemical as well as genome analyses indicate that the cytosolic MVA pathway is generally absent from Chlorophyta. We investigated the distribution of genes for both pathways in the green alga Mesostigma viride, a key species at the basis of streptophycean (charophycean green algae, land plant) evolution. Ten of altogether twelve generally weakly expressed genes for isoprenoid biosynthesis, including three for the cytosolic MVA pathway, were amplified using a reverse transcription PCR approach with individually designed degenerate primers. Two full length cDNA clones for the first enzyme of the MVA pathway (HMGS) were additionally established from the charophycean green alga Chara vulgaris by library screening. The presence of the MVA pathway in these advanced green algae indicates a universal distribution among Streptophyta, and our phylogenetic HMGS analyses substantiate the recent classification of Mesostigma basal to charophytes and land plants. We identified each of the five cytosolic MVA genes/cDNAs in the genome of the rhodophyte Galdieria sulphuraria and, furthermore, amplified four of them from the glaucophyte Cyanophora paradoxa. Our data indicate that the MVA pathway is a characteristic trait of Plantae in general and propose that it was specifically lost in a common ancestor of Chlorophyta. PMID:17433859

Grauvogel, Carina; Petersen, Jörn

2007-07-01

124

Chloroplast-mitochondria cross-talk in diatoms.  

PubMed

Diatoms are unicellular, mainly photosynthetic, eukaryotes living within elaborate silicified cell walls and believed to be responsible for around 40% of global primary productivity in the oceans. Their abundance in aquatic ecosystems is such that they have on different occasions been described as the insects, the weeds, or the cancer cells of the ocean. In contrast to higher plants and green algae which derive from a primary endosymbiosis, diatoms are now believed to originate from a serial secondary endosymbiosis involving both green and red algae and a heterotrophic exosymbiont host. As a consequence of their dynamic evolutionary history, they appear to have red algal-derived chloroplasts empowered largely by green algal proteins, working alongside mitochondria derived from the non-photosynthetic exosymbiont. This review will discuss the evidence for such an unusual assemblage of organelles in diatoms, and will present the evidence implying that it has enabled them with unorthodox metabolisms that may have contributed to their profound ecological success. PMID:22268145

Prihoda, Judit; Tanaka, Atsuko; de Paula, Wilson B M; Allen, John F; Tirichine, Leďla; Bowler, Chris

2012-02-01

125

Biological importance of marine algae  

PubMed Central

Marine organisms are potentially prolific sources of highly bioactive secondary metabolites that might represent useful leads in the development of new pharmaceutical agents. Algae can be classified into two main groups; first one is the microalgae, which includes blue green algae, dinoflagellates, bacillariophyta (diatoms)… etc., and second one is macroalgae (seaweeds) which includes green, brown and red algae. The microalgae phyla have been recognized to provide chemical and pharmacological novelty and diversity. Moreover, microalgae are considered as the actual producers of some highly bioactive compounds found in marine resources. Red algae are considered as the most important source of many biologically active metabolites in comparison to other algal classes. Seaweeds are used for great number of application by man. The principal use of seaweeds as a source of human food and as a source of gums (phycocollides). Phycocolloides like agar agar, alginic acid and carrageenan are primarily constituents of brown and red algal cell walls and are widely used in industry.

El Gamal, Ali A.

2009-01-01

126

[Evolutional relationships of endemic green algae Draparnaldioides simplex from Lake Baikal with nonbaicalian taxa of family Chaetoforaceae (Chlorophyta)].  

PubMed

Phylogenetic relationships between the endemic baicalian green algae Draparnaldioides simplex C. meyer et Skabitsch, 1976 and holarctic taxa of green algae were studied using the fragment of 18S rDNA and internal transcribed spacers ITS1 and ITS2 of nuclear DNA. We showed that the baicalian genus Draparnaldioides is a separate taxon. The genetic difference between Draparnaldioides and nonbaicalian taxa of the sister groups of the green algae are small enough to indicate relative youth of the genus Draparnaldioides and its recent radiation from a common ancestor with Draparnaldia and Chaetophora. PMID:23705507

Mincheva, E V; Peretolchina, T E; Izhboldina, L A; Kravtsova, L S; Shcherbakov, D Iu

2013-01-01

127

Phylogenetic and morphological characterisation of the green algae infesting blue mussel Mytilus edulis in the North and South Atlantic oceans.  

PubMed

Blue mussels Mytilus edulis with shell deformations and green pustules containing parasitic algae were collected at 3 coastal sites (Burřy, Norway; Bockholm, Denmark; Goose Green, Falkland Islands). A comparative study, including mussel histopathology, algal morphology, ultrastructure and phylogenetic position was performed. Green pustules were mainly located in the posterior portion of the mantle and gonad tissues and the posterior adductor muscle. Electron microscopy confirmed the presence of algal cells with similar morphology to Coccomyxa parasitica. Algae were oval shaped with a single nucleus and chloroplast, 1 or 2 mitochondria and a dense granular cytoplasm with a lipid inclusion body, Golgi apparatus and small vesicles. Partial small subunit (SSU) rRNA phylogeny confirmed the inclusion of parasitic algae into the Coccomyxa clade. However, the sequence identity between almost full SSU rRNA sequences of parasitic algae and others in this clade yielded an unexpected result. Green algae from mussels were distant from C. parasitica Culture Collection of Algae and Protozoa (CCAP) strain 216/18 (94% identity), but very similar (99% identity) to C. glaronensis (a lichen endosymbiont) and green endophytes from the tree Ginkgo biloba. The CCAP strain 216/18 was a sister sequence to Nannochloris algae, far from the Coccomyxa clade. These results suggest a misidentification or outgrowth of the original CCAP strain 216/18 by a different 'Nannochloris-like' trebouxiophycean organism. In contrast, our sequences directly obtained from infested mussels could represent the true C. parasitica responsible for the green pustules in blue mussels. PMID:18998587

Rodríguez, Francisco; Feist, Stephen W; Guillou, Laure; Harkestad, Lisbeth S; Bateman, Kelly; Renault, Tristan; Mortensen, Stein

2008-09-24

128

Hydrogen production by the green alga Scenedesmus acutus  

SciTech Connect

H production by Scenedesmus acutus was studied, with special attention to the suitability of Na2S2O4 as an O-binding compound and the effect of light intensity and initial H pressure. Na2S2O4 is an efficient O binder. However, Na2S2O4 concentrations are more than 12 mM proved to be toxic to the algae. With an optimum light intensity of 2 klx, the H production stopped at a maximum H concentration of 5% in the gaseous phase. When the gaseous phase over the culture was replaced by N periodically, H production continued for more than 9 weeks in a medium which only consisted of a phosphate buffer.

Ten Hoopen, H.J.G.; Snellink, L.J.; Van Gemert, J.M.; Fuchs, A.; Roels, J.A.

1984-01-01

129

The effect of low temperature on Antarctic endolithic green algae  

NASA Technical Reports Server (NTRS)

Laboratory experiments show that undercooling to about -5 degrees C occurs in colonized Beacon sandstones of the Ross Desert, Antarctica. High-frequency temperature oscillations between 5 degrees C and -5 degrees C or -10 degrees C (which occur in nature on the rock surface) did not damage Hemichloris antarctica. In a cryomicroscope, H. antarctica appeared to be undamaged after slow or rapid cooling to -50 degrees C. 14CO2 incorporation after freezing to -20 degrees C was unaffected in H. antarctica or in Trebouxia sp. but slightly depressed in Stichococcus sp. (isolated from a less extreme Antarctic habitat). These results suggest that the freezing regime in the Antarctic desert is not injurious to endolithic algae. It is likely that the freezing-point depression inside the rock makes available liquid water for metabolic activity at subzero temperatures. Freezing may occur more frequently on the rock surface and contribute to the abiotic nature of the surface.

Meyer, M. A.; Morris, G. J.; Friedmann, E. I.

1988-01-01

130

Phylogenetic and morphological characterisation of the green algae infesting blue mussel Mytilus edulis in the North and South Atlantic oceans  

Microsoft Academic Search

Blue mussels Mytilus edulis with shell deformations and green pustules containing par- asitic algae were collected at 3 coastal sites (Burřy, Norway; Bockholm, Denmark; Goose Green, Falkland Islands). A comparative study, including mussel histopathology, algal morphology, ultra- structure and phylogenetic position was performed. Green pustules were mainly located in the pos- terior portion of the mantle and gonad tissues and

Francisco Rodríguez; Stephen W. Feist; Laure Guillou; Lisbeth S. Harkestad; Kelly Bateman; Tristan Renault; Stein Mortensen

2008-01-01

131

The Complete Mitochondrial DNA Sequences of Nephroselmis olivacea and Pedinomonas minor : Two Radically Different Evolutionary Patterns within Green Algae  

Microsoft Academic Search

Green plants appear to comprise two sister lineages, Chlorophyta (classes Chlorophyceae, Ulvophyceae, Trebouxio- phyceae, and Prasinophyceae) and Streptophyta (Charophyceae and Embryophyta, or land plants). To gain insight into the nature of the ancestral green plant mitochondrial genome, we have sequenced the mitochondrial DNAs (mtDNAs) of Nephroselmis olivacea and Pedinomonas minor . These two green algae are presumptive members of the

Monique Turmel; Claude Lemieux; Gertraud Burger; B. Franz Lang; Christian Otis; Isabelle Plante; Michael W. Gray

1999-01-01

132

A clade uniting the green algae Mesostigma viride and Chlorokybus atmophyticus represents the deepest branch of the Streptophyta in chloroplast genome-based phylogenies  

Microsoft Academic Search

BACKGROUND: The Viridiplantae comprise two major phyla: the Streptophyta, containing the charophycean green algae and all land plants, and the Chlorophyta, containing the remaining green algae. Despite recent progress in unravelling phylogenetic relationships among major green plant lineages, problematic nodes still remain in the green tree of life. One of the major issues concerns the scaly biflagellate Mesostigma viride, which

Claude Lemieux; Christian Otis; Monique Turmel

2007-01-01

133

Effects of DCMU on chlorophyll fluorescence ratio F685/F735 in marine red, brown and green algae  

NASA Astrophysics Data System (ADS)

The chlorophyll fluorescence ratio F685/F735 in vivo can be a useful indicator for stress detection in higher plants and seaweeds. DCMU [3-(3,4-dichlorophenyl)-1, 1-dimethylurea] treatment influences this ratio. The effets of DCMU on F685/F735 of marine red, brown and green algae under excitation light of different wavelengths were investigated. In the brown algae, Laminaria japonica and Undaria pinnatifida, DCMU did not increase this ratio under blue light excitation but increased the ratio slightly under excitation by green light. For the red algae, Halymenia sinensis, DCMU increased the ratio markedly under both blue and green light excitation. The percentage increase could reach 50% (under green light excitation) and was due to unequal enhancement at the two emission maxima by DCMU. A fraction of chlorophyll which contributed to fluorescence in the 735 nm region was less sensitive to DCMU and was likely from photosystem I of red algae. In the green alga, Ulva pertusa, DCMU caused a slight increase in F685/F735 value under blue, green and red light. Green light excitation during DCMU treatment increased the ratio most (16%) but induced the lowest ratio in the control (without DCMU). It is proposed that a considerable fraction of fluorescence from the 735 nm region at room temperature may be emitted by the chlorophyll of photosystem I in red algae.

Wu, Bao-Gan; Zuo, Dong-Mei; Zang, Ru-Bo

1996-03-01

134

Substitution rate calibration of small subunit ribosomal RNA identifies chlorarachniophyte endosymbionts as remnants of green algae.  

PubMed Central

Chlorarachniophytes are amoeboid algae with chlorophyll a and b containing plastids that are surrounded by four membranes instead of two as in plants and green algae. These extra membranes form important support for the hypothesis that chlorarachniophytes have acquired their plastids by the ingestion of another eukaryotic plastid-containing alga. Chlorarachniophytes also contain a small nucleus-like structure called the nucleomorph situated between the two inner and the two outer membranes surrounding the plastid. This nucleomorph is a remnant of the endosymbiont's nucleus and encodes, among other molecules, small subunit ribosomal RNA. Previous phylogenetic analyses on the basis of this molecule provided unexpected and contradictory evidence for the origin of the chlorarachniophyte endosymbiont. We developed a new method for measuring the substitution rates of the individual nucleotides of small subunit ribosomal RNA. From the resulting substitution rate distribution, we derived an equation that gives a more realistic relationship between sequence dissimilarity and evolutionary distance than equations previously available. Phylogenetic trees constructed on the basis of evolutionary distances computed by this new method clearly situate the chlorarachniophyte nucleomorphs among the green algae. Moreover, this relationship is confirmed by transversion analysis of the Chlorarachnion plastid small subunit ribosomal RNA.

Van de Peer, Y; Rensing, S A; Maier, U G; De Wachter, R

1996-01-01

135

Sacrificial cell death and trichome breakage in an oscillatoriacean blue-green alga: the role of murein  

Microsoft Academic Search

Trichomes of Microcoleus vaginatus, a motile blue-green alga of the family Oscillatoriaceae, were studied by light and electron microscopy in an effort to determine the sites of trichome breakage during production of hormogonia.

Hayes C. Lamont

1969-01-01

136

Evidence and Analysis of Radioresistance Induced by Protracted gamma Irradiation of Chlorella Pyrenoidosa Chick, Green Unicellular Alga.  

National Technical Information Service (NTIS)

Chlorella cells, unicellular green algae, are a suitable living material to study radiosensitivity of eucaryotic cells after acute or protracted gamma irradiations. Cell survival and survival curves are taken as end-points. Methods of irradiation were def...

S. Santier-Riviere

1984-01-01

137

Growth of Legionella pneumophila in association with blue-green algae (Cyanobacteria)  

SciTech Connect

Legionella pneumophila (Legionnaires disease bacterium) of serogroup 1 was isolated from an algal-bacterial mat community growing at 45/sup 0/C in a man-made thermal effluent. This isolate was grown in mineral salts medium at 45/sup 0/C in association with the blue-green alga (cyanobacterium) Fischerella sp. over a pH range of 6.9 to 7.6. L. pneumophila was apparently using algal extracellular products as its carbon and energy sources. These observations indicate that the temperature, pH, and nutritional requirements of L. pneumophila are not as stringent as those previously observed when cultured on complex media. This association between L. pneumophila and certain blue-green algae suggests an explanation for the apparent widespread distribution of the bacterium in nature.

Tison, D.L. (Rensselaer Polytechnic Inst., Troy, NY); Pope, D.H.; Cherry, W.B.; Fliermans, C.B.

1980-02-01

138

Rapid surface plasmon resonance immunobiosensor assay for microcystin toxins in blue-green algae food supplements  

Microsoft Academic Search

A surface plasmon resonance (SPR) immunobiosensor assay was developed and validated to detect microcystin toxins in Spirulina and Aphanizomenon flos-aquae blue-green algae (BGA) food supplements. A competitive inhibition SPR-biosensor was developed using a monoclonal antibody to detect microcystin (MC) toxins. Powdered BGA samples were extracted with an aqueous methanolic solution, centrifuged and diluted in HBS-EP buffer prior to analysis. The

Tatiana Vinogradova; Martin Danaher; Andrew Baxter; Mary Moloney; Danielle Victory; Simon A. Haughey

2011-01-01

139

Purification and characterisation of an intracellular carbonic anhydrase from the unicellular green alga Coccomyxa  

Microsoft Academic Search

An intracellular carbonic anhydrase (CA; EC 4.2.1.1) was purified and characterised from the unicellular green alga Coccomyxa sp. Initial studies showed that cultured Coccomyxa cells contain an intracellular CA activity around 100 times higher than that measured in high-CO2-grown cells of Chlamydomonas reinhardtii CW 92. Purification of a protein extract containing the CA activity was carried out using ammonium-sulphate precipitation

Thomas Hiltonen; Jan Karlsson; Kristin Palmqvist; Adrian K. Clarke; GiJran Samuelsson

1995-01-01

140

The family of DOF transcription factors: from green unicellular algae to vascular plants  

Microsoft Academic Search

This article deals with the origin and evolution of the DOF transcription factor family through a phylogenetic analysis of\\u000a those DOF sequences identified from a variety of representative organisms from different taxonomic groups: the green unicellular\\u000a alga Chlamydomonas reinhardtii, the moss Physcomitrella patens, the fern Selaginella moellendorffii, the gymnosperm Pinus taeda, the dicotyledoneous Arabidopsis thaliana and the monocotyledoneous angiosperms Oryza

Miguel Ángel Moreno-Risueno; Manuel Martínez; Jesús Vicente-Carbajosa; Pilar Carbonero

2007-01-01

141

Isoprenoid biosynthesis authenticates the classification of the green alga Mesostigma viride as an ancient streptophyte  

Microsoft Academic Search

Land plants harbor two essential and completely different metabolic pathways for isoprenoid synthesis. The cytosolic mevalonate pathway (MVA) is shared with heterotrophic eukaryotes, whereas the plastidial 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway has a cyanobacterial origin and was recruited after primary endosymbiosis. Terrestrial plants and green algae have a common evolutionary ancestry, but biochemical as well as genome analyses indicate that the

Carina Grauvogel; Jörn Petersen

2007-01-01

142

Influence of blue-green algae (cyanobacteria) on survival of Legionella pneumophila in aerosols.  

PubMed Central

The fluid in which blue-green algae (cyanobacteria) (Fischerella sp.) had been grown (algal extract) was investigated for its effect on aerosols of Legionella pneumophila. The bacteria were significantly more stable when suspended in algal extract than in the tryptose-saline solution employed in previously reported experiments. The stabilizing property of the extract disappeared after dialysis, suggesting that a relatively small molecule was involved. The relationship of this observation to the epidemiology of Legionnaires disease is discussed.

Berendt, R F

1981-01-01

143

Nitrogenase activity, amino acid pool patterns and amination in blue-green algae  

Microsoft Academic Search

The free amino acid pools in the nitrogen-fixing blue-green algae Anabaena cylindrica, A. flos-aquae and Westiellopsis prolifica contain a variety of amino acids with aspartic acid, glutamic acid and the amide glutamine being present in much higher concentrations than the others. This pattern is characteristic of that found in organisms having glutamine synthetage\\/glutamate synthetase [glutamine amide-2-oxoglutarate amino transferase (oxido-reductase)] as

M. W. N. Dharmawardene; W. D. P. Stewart; S. O. Stanley

1972-01-01

144

Are blue-green algae a suitable food for zooplankton? An overview  

Microsoft Academic Search

One of the reasons suggested to explain the dominance of blue-greens in eutrophic lakes is that they are not used as food\\u000a by zooplankton; and even when ingested, they are poorly utilized.\\u000a \\u000a An increase in herbivores might be the expected result of biomanipulation of the aquatic food chain. This attempt at controlling\\u000a the algae population is, however, destined to fail

R. de Bernardi; G. Giussani

1990-01-01

145

Photosynthetic and dark carbon metabolism in unicellular blue-green algae  

Microsoft Academic Search

0946 091.The kinetics of 14CO2 incorporation into cellular intermediates was used to determine the primary pathway of carbon fixation by four genetically diverse unicellular blue-green algae. In each case label was first detected in 3-phosphoglycerate and then in compounds of the reductive pentose cycle.2.A light to dark transition evoked the same response in all four strains: Immediate cessation of biosynthesis,

R. A. Pelroy; J. A. Bassham

1972-01-01

146

Electron microscopy of polyphosphate bodies in a blue-green alga, Nostoc pruniforme  

Microsoft Academic Search

Preparations of the blue-green alga, Nostoc pruniforme, treated according to the lead-sulfide staining technique of Ebelet al. (1958b) were examined by light and electron microscopy. They were found to contain spherical, electron-dense bodies, generally in close association with the nucleoplasm and polyhedral bodies, and sometimes enclosed by a membrane. In preparations extracted with cold TCA prior to the application of

Thomas E. Jensen

1968-01-01

147

Nitrogenase activity in extracts of heterocystous and non-heterocystous blue-green algae  

Microsoft Academic Search

Cell-free extracts capable of acetylene reduction and cyanide reduction have been prepared from heterocystous (Anabaena cylindrica) and non-heterocystous (Plectonema boryanum 594) blue-green algae. Extracts from Anabaena were obtained from cultures grown in blulk under aerobic conditions, while the Plectonema cultures were grown in bulk on nitrate-nitrogen, then washed free from nitrate and sparged with A\\/CO2 for 40 h after which

A. Haystead; R. Robinson; W. D. P. Stewart

1970-01-01

148

Antioxidant and anti-inflammatory properties of C-phycocyanin from blue-green algae  

Microsoft Academic Search

Objective: Phycocyanin is a pigment found in blue-green algae which contains open chain tetrapyrroles with possible scavenging properties. We have studied its antioxidant properties.¶Materials and methods: Phycocyanin was evaluated as a putative antioxidant in vitro by using: a) luminol-enhanced chemiluminescence (LCL) generated by three different radical species (Oф, OH”, RO”) and by zymosan activated human polymorphonuclear leukocytes (PMNLs), b) deoxyribose

C. Romay; J. Armesto; D. Remirez; R. González; N. Ledon; I. García

1998-01-01

149

Ion metabolism in a halophilic blue-green alga, Aphanothece halophytica  

Microsoft Academic Search

The intracellular ion content of the halophilic blue-green alga, Aphanothece halophytica was studied as a function of age, external sodium and external potassium concentration. Intracellular Na+ was found to be about 0.38 millimoles\\/g dry mass. Intracellular K+ concentrations were as high as 1 M and varied directly with external salinity. Intracellular Ca++ and Mg++ were in the range previously reported

Donald M. Miller; Jay H. Jones; John H. Yopp; Donald R. Tindall; Walter E. Schmid

1976-01-01

150

Growth inhibition of blue–green algae by allelopathic effects of macrophytes  

Microsoft Academic Search

Inhibitory effects of macrophytes on the growth of blue-green algae (i.e. Microcystis oeruginosa, Anoboena flos-aquae, or Phormidium tenue) were evaluated in a coexistence culture system in which concentrations of different macrophyte species were varied (i.e. Egeria densa, Cabomba caroliniana. Myriophyllutn spicatum, Ceratophyllum demersum, Eleocharis acicularis, Potamogeton oxyphyllus, Potamogeton crispus, Limnophila sessilifloro, or Vallisneria denseserrulata). Coexistence assay results showed that only

Satoshi Nakai; Yutaka Inoue; Masaaki Hosomi; Akihiko Murakami

1999-01-01

151

Heterotrophic Nitrogen Fixation by the Blue-Green Alga Anabaenopsis circularis  

Microsoft Academic Search

IT has been shown that the blue-green alga Tolypothrix tenuis can be grown heterotrophically in complete darkness if, as well as mineral nutrients, appropriate organic substances such as casamino-acid are supplied as sources of nitrogen and carbon1. The maximum values for the growth rate and final growth yield obtained in heterotrophic conditions, however, were found to be far less than

Atsushi Watanabe; YOKO YAMAMOTO

1967-01-01

152

Myriophyllum spicatum-released allelopathic polyphenols inhibiting growth of blue-green algae Microcystis aeruginosa  

Microsoft Academic Search

A culture solution of macrophyte Myriophyllum spicatum was subjected to algal assay-directed fractionation on the basis of polarity and molecular weight. As the water-soluble fraction below molecular weight 1000 was the only fraction to inhibit the growth of blue-green algae Microcystis aeruginosa, it was analyzed by analytical high-performance liquid chromatography (HPLC) and atmospheric pressure chemical ionization mass spectrometry (APCI-MS) in

Satoshi Nakai; Yutaka Inoue; Masaaki Hosomi; Akihiko Murakami

2000-01-01

153

Polyhedral bodies (carboxysomes) of nitrogen-fixing blue-green algae  

Microsoft Academic Search

Blue-green algae possess polyhedral bodies which, under the electron microscope, resemble the carboxysomes containing ribulose-1-5-diphosphate carboxylase (RUDPCase) in the chemoautotrophic bacterium Thiobacillus. These bodies are present in vegetative cells but not the heterocysts of 15 strains of Anabaena, Nostoc, Plectonema and Westiellopsis, including material grown photoautotrophically, photoheterotrophically and dark heterotrophically. They are also present in spores (akinetes). Their absence from

W. D. P. Stewart; G. A. Codd

1975-01-01

154

5-Aminolevulinate Synthesis in Permeabilized Filaments of the Blue-Green Alga Anabaena variabilis  

PubMed Central

Filaments of the blue-green alga Anabaena variabilis permeabilized by dimethylsulfoxide (DMSO) produce increased amounts of 5-aminolevulinate in the presence of levulinic acid. The metabolic activity of the filaments remains unperturbed in the presence of up to 7.5% (v/v) DMSO. Studies utilizing DMSO-permeabilized filaments confirm that 5-aminolevulinate is synthesized preferably from glutamate and, to a lesser extent, from ?-ketoglutarate in this organism.

Avissar, Yael J.

1983-01-01

155

Viruses of eukaryotic green algae. Final technical report, June 1, 1989--February 1, 1992  

SciTech Connect

We have isolated and partially characterized many large, polyhedral, DNA containing, plaque forming viruses which infect certain unicellular, eukaryotic, chlorella-like green algae. These viruses have several unique features, including the fact that they code for DNA site-specific endonucleases and DNA methyltransferases. The primary objectives of this study were to identify, clone, and characterize some of the virus-encoded DNA methyltransferases and DNA restriction endonucleases in order to understand their biological function.

Van Etten, J.L.

1992-12-31

156

Viruses of eukaryotic green algae. Progress report, August 1, 1982-July 1, 1984  

SciTech Connect

The virus, PBCV-1, which infects the eukaryotic, green alga, Chlorella-NC64A has been characterized and we have begun to look at detailed events associated with its growth cycle. In addition, we have recently discovered other dsDNA viruses from natural sources which replicate in Chlorella NC64A. These viruses can be distinguished from PBCV-1 and from each other by plaque morphology, DNA restriction patterns, and by their resistance to certain restriction endonucleases.

Van Etten, J.L.

1984-01-01

157

Predicting the Physiological Role of Circadian Metabolic Regulation in the Green Alga Chlamydomonas reinhardtii  

PubMed Central

Although the number of reconstructed metabolic networks is steadily growing, experimental data integration into these networks is still challenging. Based on elementary flux mode analysis, we combine sequence information with metabolic pathway analysis and include, as a novel aspect, circadian regulation. While minimizing the need of assumptions, we are able to predict changes in the metabolic state and can hypothesise on the physiological role of circadian control in nitrogen metabolism of the green alga Chlamydomonas reinhardtii.

Voytsekh, Olga; Mittag, Maria; Schuster, Stefan

2011-01-01

158

Metabolic Activities of Isolated Heterocysts of the Blue-green Alga Anabaena cylindrica  

Microsoft Academic Search

KNOWLEDGE of the nature of the heterocysts of blue-green algae has been limited by the lack of suitable techniques for investigation of the physiology and biochemistry of these puzzling structures. The association of the presence of heterocysts with the ability to fix free nitrogen and the findings1,2 that ammonia suppresses both nitrogen fixation and heterocyst formation have led to the

P. Fay; A. E. Walsby

1966-01-01

159

Inhibition of nitrate uptake by ammonia in a blue-green alga, Anabaena cylindrica  

Microsoft Academic Search

Ammonia at concentrations above 1×10-5 M inhibits uptake of nitrate in the nitrogen-fixing blue-green alga, Anabaena cylindrica. This inhibition takes place both in the light and in the dark. The rate of nitrate uptake is stimulated by light. Addition of relatively high concentrations of nitrate (1–10 mM) reversibly inhibits ammonia uptake. FCCP, an uncoupler of phosphorylation, inhibits both nitrate and

Masayuki Ohmori; Kazuko Ohmori; Heinrich Strotmann

1977-01-01

160

The Metabolism of Acetate by the Blue-green Algae, Anabaena variabilis and Anacystis nidulans  

Microsoft Academic Search

SUMMARY The utilization of acetate by blue-green algae was examined and the activities of enzymes involved in its metabolism measured. Although acetate did not stimulate the endogenous respiration of these organisms, the oxida- tion of acetate was followed by the rate of release of (14C) carbon dioxide from (I-~~CC) and (2-l4CC) sodium acetate. Similarly, sodium acetate did not alter the

J. Pearce; N. G. Carr

1967-01-01

161

Pathways of glycollate metabolism in the blue-green alga Anabaena cylindrica  

Microsoft Academic Search

1.Exogenous glycollate was assimilated by the blue-green alga Anabaena cylindrica.2.About 50% of the C-1 carbon of 14C-1-glycollate (i.e.25% of the total carbon) was released as 14CO2 in the dark and also in the light in the presence of DCMU. Most of the 14CO2 released in the light in the absence of DCMU was refixed.3.Assimilation was almost completely inhibited by a-hydroxy-2-pyridinemethane

G. A. Codd; W. D. P. Stewart

1973-01-01

162

Biodegradation of the Pesticide Fenamiphos by Ten Different Species of Green Algae and Cyanobacteria  

Microsoft Academic Search

The degradation of an organophosphorus pesticide, fenamiphos, by different species of five green algae and five cyanobacteria\\u000a was studied. All the species tested were able to transform fenamiphos to its primary oxidation product, fenamiphos sulfoxide\\u000a (FSO), while the majority of these cultures were able to hydrolyze FSO to fenamiphos sulfoxide phenol (FSOP). Fenamiphos sulfone\\u000a phenol, FSOP, and FSO were detected

Tanya P. Cáceres; Mallavarapu Megharaj; Ravi Naidu

2008-01-01

163

Cultivation of Green Algae Chlorella sp. in Different Wastewaters from Municipal Wastewater Treatment Plant  

Microsoft Academic Search

The objective of this study was to evaluate the growth of green algae Chlorella sp. on wastewaters sampled from four different points of the treatment process flow of a local municipal wastewater treatment\\u000a plant (MWTP) and how well the algal growth removed nitrogen, phosphorus, chemical oxygen demand (COD), and metal ions from\\u000a the wastewaters. The four wastewaters were wastewater before

Liang Wang; Min Min; Yecong Li; Paul Chen; Yifeng Chen; Yuhuan Liu; Yingkuan Wang; Roger Ruan

2010-01-01

164

Transient expression of firefly luciferase in protoplasts of the green alga Chlorella ellipsoidea  

Microsoft Academic Search

We report here on the development of a transient expression system for Chlorella ellipsoidea using a heterologous gene, firefly luciferase. Cells of this unicellular green alga were converted to protoplasts and treated with plasmid pDO432, which bears luciferase under the control of the CaMV 35S promoter. This treatment resulted in detectable luciferase activity in cell extracts. Expression required Cellulysin treatment,

Eric E. Jarvis; Lewis M. Brown

1991-01-01

165

The effect of sulfide on the blue-green algae of hot springs II. Yellowstone National Park  

Microsoft Academic Search

In the Mammoth Springs (Yellowstone National Park) waters with near neutral pH and soluble sulfide (H2S, HS?, S2?) of over 1–2 mg\\/liter (30–60?M) are characterized by substrate covers of phototrophic bacteria (Chloroflexus and aChlorobium-like unicell) above 50‡C and by a blue-green alga (Spirulina labyrinthiformis) below this temperature.Synechococcus. Mastigocladus, and other blue-green algae typical of most hot springs of western North

Richard W. Castenholz

1977-01-01

166

The Mechanism Analysis of How Blue-Green Algae in Taihu Lake Affects the Residents' Quality of Life  

Microsoft Academic Search

This paper defines the concept of quality of life, and analyses the diffusion process about the event of blue-green algae in Taihu Lake. Based on this, it analyses the mechanism of how blue-green algae in Taihu Lake Affects the residents' quality of life, from five facets ,such as living standards, social support, the natural environment, the residents'quality of Leisure life,

Sun Fuhua; Shen Juqin; Ji Jian; Xu Li

2010-01-01

167

Structural Characterization of Toxic Cyclic Peptides from Blue-Green Algae by Tandem Mass Spectrometry  

Microsoft Academic Search

Combined use of chemical degradation, derivatization, and tandem mass spectrometry for rapid structural characterization of toxic cyclic peptides from blue-green algae at the nanomole level is described. Previously, all blue-green algal toxins were thought to belong to a family of seven-residue cyclic peptides, having the general structure cyclo-D-Ala-L-Xaa-erythro-beta -methyl-D-isoaspartic acid-L-Yaa-Adda-D-isoglutamic acid-N-methyldehydroalanine, where Xaa and Yaa represent variable amino acids of

Thaiya Krishnamurthy; Linda Szafraniec; Donald F. Hunt; Jeffrey Shabanowitz; John R. Yates; Charles R. Hauer; Wayne W. Carmichael; Olav Skulberg; Geoffrey A. Codd; Stephen Missler

1989-01-01

168

Identification of a symbiotic fungus from blue-green alga and its extracellular polysaccharide.  

PubMed

A previously unknown symbiotic fungus DT06 has been isolated from the single-celled blue-green alga Chroococcus sp. The sequences of ITS1, 5.8S rDNA and ITS2 regions of DT06 have a high similarity with that of Simplicillium (98%), which is closely related to Simplicillium lanosoniveum based on further phylogenetic analysis. However, DT06 produces unusual exocellular crystals with its conidium size twice that of S. lanosoniveum. Hence, DT06 is proposed to be a varietas of S. lanosoniveum and named as S. lanosoniveum var. Tianjinienss. Dong. (Type specimen was deposited at China General Microbiological Culture Collection Center, Number: CGMCC4460.). The striking character of DT06 is its massive production of a unique extracellular polysaccharide, which is composed of glucose and galactose and linked by 1-4 and 1-6 glycoside bonds according to UV, IR and NMR analysis. Therefore, DT06 may represent a new source of bioactive products, and also, its unusual symbiotic partnership with blue-green algae provides a model for investigating the interaction between photoautotrophic and heterotrophic micro-organisms in aquatic ecosystems. Significance and impact of the study: A novel fungus (Simplicillium) symbiotic with a single-celled blue-green alga Chroococcus sp. and its major primary metabolite have been isolated and identified. These findings broaden the scope of symbiotic fungi and provide a unique extracellular polysaccharide with potential applications in food industry. PMID:24261819

Dong, Q L; Lin, T Y; Xing, X Y; Chen, B; Han, Y

2014-04-01

169

Phylogenetic analysis identifies the invertebrate pathogen Helicosporidium sp. as a green alga (Chlorophyta).  

PubMed

Historically, the invertebrate pathogens of the genus Helicosporidium were considered to be either protozoa or fungi, but the taxonomic position of this group has not been considered since 1931. Recently, a Helicosporidium sp., isolated from the blackfly Simulium jonesi Stone & Snoddy (Diptera: Simuliidae), has been amplified in the heterologous host Helicoverpa zea. Genomic DNA has been extracted from gradient-purified cysts. The 185, 28S and 5.8S regions of the Helicosporidium rDNA, as well as partial sequences of the actin and beta-tubulin genes, were amplified by PCR and sequenced. Comparative analysis of these nucleotide sequences was performed using neighbour-joining and maximum-parsimony methods. All inferred phylogenetic trees placed Helicosporidium sp. among the green algae (Chlorophyta), and this association was supported by bootstrap and parsimony jackknife values. Phylogenetic analysis focused on the green algae depicted Helicosporidium sp. as a close relative of Prototheca wickerhamii and Prototheca zopfii (Chlorophyta, Trebouxiophyceae), two achlorophylous, pathogenic green algae. On the basis of this phylogenetic analysis, Helicosporidium sp. is clearly neither a protist nor a fungus, but appears to be the first described algal invertebrate pathogen. These conclusions lead us to propose the transfer of the genus Helicosporidium to Chlorophyta, Trebouxiophyceae. PMID:11837312

Tartar, Aurélien; Boucias, Drion G; Adams, Byron J; Becnel, James J

2002-01-01

170

Algae.  

PubMed

Algae frequently get a bad press. Pond slime is a problem in garden pools, algal blooms can produce toxins that incapacitate or kill animals and humans and even the term seaweed is pejorative - a weed being a plant growing in what humans consider to be the wrong place. Positive aspects of algae are generally less newsworthy - they are the basis of marine food webs, supporting fisheries and charismatic marine megafauna from albatrosses to whales, as well as consuming carbon dioxide and producing oxygen. Here we consider what algae are, their diversity in terms of evolutionary origin, size, shape and life cycles, and their role in the natural environment and in human affairs. PMID:25004359

Raven, John A; Giordano, Mario

2014-07-01

171

The prospect function of terrestrial nitrogen-fixing blue-green algae on the fixation of desert  

NASA Astrophysics Data System (ADS)

The Terrestrial Nitrogen-fixing Blue-green Algae, which are possessed of both photosynthesis and nitrogen fixation, are the leading organisms in the adverse circumstances. With their typical cell structures and physiological abilities, they are strongly resistant to drought, infertility etc. The growth of Terrestrial Nitrogen-fixing Blue-green Algae can rich the soils in nitrogen and organic compounds, which are benefit to other microbes and plants. Terrestrial Nitrogen-fixing Blue-green Algae are widely distributed in Gurbantunggut Desert. It was estimated that about 40% of the surface of the desert are covered by the "Black Crust". "Black Crust" is mainly occupied by Terrestrial Nitrogen-fixing Blue-green Algae. It is Terrestrial Nitrogen-fixing Blue-green Algae that construct the mechanical crust with a little other algae and fungi through biological, chemical and physical actions. So Terrestrial Nitrogen-fixing Blue-green Algae play an important part in desert fixation. It was analyzed that there are three species of the blue-greens in the "Black Crust": Microcoleus vaginatus(Vauch)Gom.,Scytonema ocellatum Lynbye and Schizothrix mella Gardner. We had isolated Microcoleus vaginatus(Vauch)Gom. and Scytonema ocellatum Lynbye. Some tests had been made to prove the feasibility of the desert fixation of the Blue-greens. Under experiment conditions, the blue-greens grown on the surface of sand, covered the sand quickly after the inoculation, and formed a mechanical fixed surface layer (7 days for Microcoleus vaginatus, 15-21 days for Scytonema ocellatum).

Yang, Yusuo; Lei, Jiaqiang

2003-07-01

172

SIMULTANEOUS SEPARATION OF CHLOROPHYLLS AND CAROTENOIDS BY RP-HPLC IN SOME ALGAE AND CYANOBACTERIA FROM THE SOUTHERN BALTIC  

Microsoft Academic Search

RP-HPLC (reversed-phase high-performance liquid chromatography) was used to analyse chlorophyll and carotenoid pigments in cyanobacteri a and algae from the Baltic Sea, belonging to different taxonomic groups. The following species w ere used: Cyclotella meneghiniana - diatom, Oocystis submarina - green alga and Phormidium amphibium - cyanobacterium. Investigations on a favourable method of chlorophyll and carotenoid p igment separation have

SABINA JODËOWSKA; ADAM LATAËA

173

Nutritional effect of five species of marine algae on the growth, development, and survival of the brine shrimp Artemia salina  

Microsoft Academic Search

Five species of unicellular algae of the same age, cultured bacteria-free under standard growth conditions, were analyzed for chemical composition and fed to different size classes of Artemia salina. The green algae Chlamydomonas sphagnicolo, Dunaliella viridis, Platymonas elliptica and Chlorella conductrix had significantly higher percentages of protein and lipid than did the diatom Nitzschia closterium. Total ash value was highest

L. V. Sick

1976-01-01

174

A cryptic intracellular green alga in Ginkgo biloba: ribosomal DNA markers reveal worldwide distribution.  

PubMed

Intracellular symbioses involving eukaryotic microalgae and a variety of heterotrophic protists and invertebrates are widespread, but are unknown in higher plants. Recently, we reported the isolation and molecular identification of a Coccomyxa-like green alga from in vitro cell cultures of Ginkgo biloba L. This alga resides intracellularly in an immature "precursor" form with a nonfunctional chloroplast, implying that algal photosynthetic activity has no role in this endosymbiosis. In necrotizing Ginkgo cells, precursors evolved into mature algae, proliferated, and were liberated into the culture medium after host cell bursting. In the present paper we demonstrate by molecular methods a worldwide distribution of the alga in planta. Endosymbiont-specific sequences of ribosomal DNA could be traced in Ginkgo tissues of each specimen examined from different geographic locations in Europe, North America, and Asia. The Ginkgo/Coccomyca association represents a new kind of intracellular, vertically inherited symbiosis. Storage bodies, probably of lipid nature, present in the cytoplasm of each partner suggest a possible involvement of the endosymbiont in metabolic pathways of its host. PMID:17503075

Trémouillaux-Guiller, Jocelyne; Huss, Volker A R

2007-07-01

175

Evaluation of antigenotoxic effects of carotenoids from green algae Chlorococcum humicola using human lymphocytes  

PubMed Central

Objective To identify the available phytochemicals and carotenoids in the selected green algae and evaluate the potential genotoxic/antigenotoxic effect using lymphocytes. Methods Organic solvent extracts of Chlorococcum humicola (C. humicola) were used for the phytochemical analysis. The available carotenoids were assessed by HPLC, and LC-MS analysis. The genotoxicity was induced by the benzo(a)pyrene in the lymphocyte culture, the genotoxic and antigenotoxic effects of algal carotenoids with and without genotoxic inducer were evaluated by chromosomal aberration (CA), sister chromatid exchange (SCE) and micronucleus assay (MN). Results The results of the analysis showed that the algae were rich in carotenoids and fatty acids. In the total carotenoids lutein, ?-carotene and ?-carotene were found to be present in higher concentration. The frequency of CA and SCE increased by benzo(a)pyrene were significantly decreased by the carotenoids (P<0.05 for CA, P<0.001 for SCE). The MN frequencies of the cells were significantly decreased by the treatment with carotenoids when compared with the positive controls (P<0.05). Conclusions The findings of the present study demonstrate that, the green algae C. humicola is a rich source of bioactive compounds especially carotenoids which effectively fight against environmental genotoxic agents, the carotenoids itself is not a genotoxic substance and should be further considered for its beneficial effects.

Bhagavathy, S; Sumathi, P

2012-01-01

176

Identification of phytochelatins in the cadmium-stressed conjugating green alga Micrasterias denticulata.  

PubMed

Aquatic environments like peat bogs are affected by anthropogenic metal input into the environment. These ecosystems are inhabited by unicellular green algae of the class Zygnematophyceae. In this study the desmid Micrasterias denticulata was stressed with 600 nM Cd, 10 ?M Cr and 300 nM Cu for 3 weeks. GSH levels were measured with HPLC and did not differ between the different treatments or the control. According to the metallo-thiolomics concept, mass spectrometry was used as a method for unambiguous thiol peptide identification. PC2, PC3 and PC4 were clearly identified in the Cd stressed sample with UPLC-MS by their MS spectrum and molecular masses. PC2 and PC3 were determined to be the main thiol compounds, while PC4 was only abundant in traces in Micrasterias. In addition, the identity of PC2 and PC3 was confirmed by MS/MS. No PCs were detected in the Cu stressed algae sample. However, in the Cr stressed sample traces of PC2 were indicated by a peak in UPLC-MS at the retention time of the PC2 standard, but the intensity was too low to acquire reliable MS and MS/MS spectra. In this study PCs have been detected for the first time in a green alga of the division Streptophyta, a close relative to higher plants. PMID:23266414

Volland, Stefanie; Schaumlöffel, Dirk; Dobritzsch, Dirk; Krauss, Gerd-Joachim; Lütz-Meindl, Ursula

2013-04-01

177

Bioaccumulation and degradation of pesticide fluroxypyr are associated with toxic tolerance in green alga Chlamydomonas reinhardtii.  

PubMed

The herbicide fluroxypyr is widely used for controlling weeds and insects but intensive use of fluroxypyr has resulted in its widespread contamination in soils and aquatic ecosystems. To evaluate the eco-toxicity of fluroxypyr to green algae, bioaccumulation and degradation of fluroxypyr in Chlamydomonas reinhardtii, a model unicellular alga, along with its biological adaptation to fluroxypyr toxicity were investigated. The microalgae were treated with fluroxypyr at 0.05-1.00 mg l(-1) for 2 days or 0.50 mg l(-1) for 1-5 days. The growth of C. reinhardtii was stimulated at low levels of fluroxypyr (0.05-0.5 mg l(-1)) but inhibited at high concentrations (0.75-1.00 mg l(-1)). Fluroxypyr was significantly accumulated by C. reinhardtii. Interestingly, the accumulated fluroxypyr could be rapidly degraded in the cells. On day 5 more than 57% of cellular fluroxypyr was degraded. Our results indicated that accumulation and degradation of fluroxypyr occurred simultaneously. Treatment with 0.05-1.00 mg l(-1) fluroxypyr for 30 min induced significant production of reactive oxygen species and as a consequence resulted in accumulation of peroxides and DNA degradation. Additionally, activities of several major antioxidant enzymes were activated in C. reinhardtii exposed to high levels of fluroxypyr. Overall, the present studies represent the initial comprehensive analyses of the green alga C. reinhardtii in adaptation to the fluroxypyr-contaminated aquatic ecosystems. PMID:21153053

Zhang, Shuang; Qiu, Chong Bin; Zhou, You; Jin, Zhen Peng; Yang, Hong

2011-03-01

178

Studies on the proteins of mass-cultivated, blue-green alga (Spirulina platensis)  

SciTech Connect

The characteristics of the protein of fresh-water, mass-cultured Spirulina platensis have been studied. The solubility of this algal protein in water and various aqueous solvents has been estimated. The total protein content of the blue-green algae was approximately 50-55% of which nearly 9.9% was nonprotein nitrogen. About 80% of the total protein nitrogen can be extracted by three successive extractions with water. Ths isoelectric point of this algal protein is found to be 3.0. The total proteins were characterized physicochemically by standard techniques. In the ultracentrifuge total proteins resolve into two major components with S20w values of 2.6 and 4.7 S. The polyacrylamide gel electrophoretic pattern of the total protein showed seven bands including three prominent ones. The in vitro digestibility of the total protein of fresh algae was found to be 85% when assayed with a pepsin-pancreatin system.

Annusuyadevi, M.; Subbulakshmi, G.; Madhair'devi, K.; Venkalaramein, L.V.

1981-05-01

179

Growth of the green algae Chlamydomonas reinhardtii under red and blue lasers  

NASA Astrophysics Data System (ADS)

Red and blue lasers, holding promise as an electric light source for photosynthetic systems on account of being true monochromatic, high-power, and having high electrical-conversion efficiency, were employed in growing a green alga, Chlamydomonas reinhardtii. The laser treatments tested included: 655-nm Red; 680-nm Red; 655-nm Red+474-nm Blue and 680-nm Red+474-nm Blue. A white cold cathode lamp with spectral output similar to that of white fluorescent lamp served as control. C. reinhardtii successfully grew and divided under the 655 and 680-nm red lasers as well as under the white-light control. Supplementing either red with blue laser, however, resulted in increased algae cell count that significantly exceeded those under both red lasers and the white-light control on average by 241%.

Kuwahara, Sara S.; Cuello, Joel L.; Myhre, Graham; Pau, Stanley

2011-03-01

180

A Lack of Parasitic Reduction in the Obligate Parasitic Green Alga Helicosporidium  

PubMed Central

The evolution of an obligate parasitic lifestyle is often associated with genomic reduction, in particular with the loss of functions associated with increasing host-dependence. This is evident in many parasites, but perhaps the most extreme transitions are from free-living autotrophic algae to obligate parasites. The best-known examples of this are the apicomplexans such as Plasmodium, which evolved from algae with red secondary plastids. However, an analogous transition also took place independently in the Helicosporidia, where an obligate parasite of animals with an intracellular infection mechanism evolved from algae with green primary plastids. We characterised the nuclear genome of Helicosporidium to compare its transition to parasitism with that of apicomplexans. The Helicosporidium genome is small and compact, even by comparison with the relatively small genomes of the closely related green algae Chlorella and Coccomyxa, but at the functional level we find almost no evidence for reduction. Nearly all ancestral metabolic functions are retained, with the single major exception of photosynthesis, and even here reduction is not complete. The great majority of genes for light-harvesting complexes, photosystems, and pigment biosynthesis have been lost, but those for other photosynthesis-related functions, such as Calvin cycle, are retained. Rather than loss of whole function categories, the predominant reductive force in the Helicosporidium genome is a contraction of gene family complexity, but even here most losses affect families associated with genome maintenance and expression, not functions associated with host-dependence. Other gene families appear to have expanded in response to parasitism, in particular chitinases, including those predicted to digest the chitinous barriers of the insect host or remodel the cell wall of Helicosporidium. Overall, the Helicosporidium genome presents a fascinating picture of the early stages of a transition from free-living autotroph to parasitic heterotroph where host-independence has been unexpectedly preserved.

Pombert, Jean-Francois; Blouin, Nicolas Achille; Lane, Chris; Boucias, Drion; Keeling, Patrick J.

2014-01-01

181

A lack of parasitic reduction in the obligate parasitic green alga Helicosporidium.  

PubMed

The evolution of an obligate parasitic lifestyle is often associated with genomic reduction, in particular with the loss of functions associated with increasing host-dependence. This is evident in many parasites, but perhaps the most extreme transitions are from free-living autotrophic algae to obligate parasites. The best-known examples of this are the apicomplexans such as Plasmodium, which evolved from algae with red secondary plastids. However, an analogous transition also took place independently in the Helicosporidia, where an obligate parasite of animals with an intracellular infection mechanism evolved from algae with green primary plastids. We characterised the nuclear genome of Helicosporidium to compare its transition to parasitism with that of apicomplexans. The Helicosporidium genome is small and compact, even by comparison with the relatively small genomes of the closely related green algae Chlorella and Coccomyxa, but at the functional level we find almost no evidence for reduction. Nearly all ancestral metabolic functions are retained, with the single major exception of photosynthesis, and even here reduction is not complete. The great majority of genes for light-harvesting complexes, photosystems, and pigment biosynthesis have been lost, but those for other photosynthesis-related functions, such as Calvin cycle, are retained. Rather than loss of whole function categories, the predominant reductive force in the Helicosporidium genome is a contraction of gene family complexity, but even here most losses affect families associated with genome maintenance and expression, not functions associated with host-dependence. Other gene families appear to have expanded in response to parasitism, in particular chitinases, including those predicted to digest the chitinous barriers of the insect host or remodel the cell wall of Helicosporidium. Overall, the Helicosporidium genome presents a fascinating picture of the early stages of a transition from free-living autotroph to parasitic heterotroph where host-independence has been unexpectedly preserved. PMID:24809511

Pombert, Jean-François; Blouin, Nicolas Achille; Lane, Chris; Boucias, Drion; Keeling, Patrick J

2014-05-01

182

The Complete Chloroplast DNA Sequence of the Green Alga Nephroselmis olivacea: Insights into the Architecture of Ancestral Chloroplast Genomes  

Microsoft Academic Search

Green plants seem to form two sister lineages: Chlorophyta, comprising the green algal classes Prasinophyceae, Ulvophyceae, Trebouxiophyceae, and Chlorophyceae, and Streptophyta, comprising the Charophyceae and land plants. We have determined the complete chloroplast DNA (cpDNA) sequence (200,799 bp) of Nephroselmis olivacea, a member of the class (Prasinophyceae) thought to include descendants of the earliest-diverging green algae. The 127 genes identified

Monique Turmel; Christian Otis; Claude Lemieux

1999-01-01

183

The growth response of the green alga Chlorella vulgaris to combined divalent cation exposure  

Microsoft Academic Search

Using the growth response of the green algaChlorella vulgaris as a model system, the effects of combinations of the environmentally active cations Cd, Co, and Cu were evaluated. The 96-h static EC50 for these cations toC. vulgaris were, respectively, 0.89 µM, 9.0 µM, and 2.8 µM, yielding a toxicity series such that Cd>Cu>Co. The cation combinations of Cd+Cu, and Cu+Co

Joseph W. Rachlin

1993-01-01

184

Plastoquinone as a common link between photosynthesis and respiration in a blue-green alga  

Microsoft Academic Search

The role of plastoquinone in a thermophilic blue-green alga, Shynechococcus sp., was studied by measuring reduction kinetics of cytochrome 553 which was oxidized with red flash preferentially exciting photosystem I. Sensitivity of the cytochrome reduction to DBMIBAbbreviations: DCMU = 3-(3,4-dichlorophenyl)-1,1-dimethylurea; DBMIB = 2,5-dib romo-3-methyl-6-isopropyl-p-benzoquinone; HOQNO = 2-n-heptyl-4-hydroxyquinoline-N-oxide indicates that cytochrome 553 accepts electrons from reduced plastoquinone. Plastoquinone is in turn

Masahiko Hirano; Kazuhiko Satoh; Sakae Katoh

1980-01-01

185

Inhibitory effects of terpene alcohols and aldehydes on growth of green alga Chlorella pyrenoidosa  

SciTech Connect

The growth of the green alga Chlorella pyrenoidosa was inhibited by terpene alcohols and the terpene aldehyde citral. The strongest activity was shown by citral. Nerol, geraniol, and citronellol also showed pronounced activity. Strong inhibition was linked to acyclic terpenes containing a primary alcohol or aldehyde function. Inhibition appeared to be taking place through the vapor phase rather than by diffusion through the agar medium from the terpene-treated paper disks used in the system. Inhibition through agar diffusion was shown by certain aged samples of terpene hydrocarbons but not by recently purchased samples.

Ikawa, Miyoshi; Mosley, S.P.; Barbero, L.J. (Univ. of New Hampshire, Durham (United States))

1992-10-01

186

Viruses of eukaryotic green algae. Progress report, August 1, 1984-March 1, 1986  

SciTech Connect

PBCV-1 is a large dsDNA-containing, plaque forming virus that replicates in a unicellular, eukaryotic Chlorella-like green alga strain NC64A. We have discovered that PBCV-1 infection results in the appearance of a restriction and modification system in the host. Furthermore, we have isolated and partially characterized 30 additional large, dsDNA-containing viruses which replicate in the same host. Some, if not all, of these viruses probably induce the synthesis of modification and restriction systems which are different from that induced by PBCV-1. 16 refs.

Van Etten, J.L.

1986-01-01

187

Transformation of trans Golgi Network During the Cell Cycle in a Green Alga, Botryococcus braunii  

Microsoft Academic Search

trans  -Golgi network (TGN), and the changes in its structure and behavior throughout the cell cycle of a unicellular green alga,\\u000a Botryococcus braunii, were examined with deep-etching replicas and in cryo-fixed\\/freeze-substituted specimens. In interphase cells, the TGN consisted\\u000a of a hemispherically shaped cisterna (TGN-cisterna) with regularly distributed pores on the surface and a tubular network\\u000a (TGN-tubules) with clathrin-coated vesicles. The TGNs

Tetsuko Noguchi; Fukiko Kakami

1999-01-01

188

Cloning and sequencing of the ferredoxin gene of blue-green alga Anabaena siamensis  

NASA Astrophysics Data System (ADS)

The structure gene for ferredoxin, petFI, from Anabaena siamensis has been amplified by polymerase chain reaction(PCR) and cloned into cloning vector pGEM-3zf(+). The nucleotide sequence of petFI has been determined with silver staining sequencing method. There is 96.8% homology between coding region of petFI from A. siamensis and that of petFI from A. sp. 7120. Amino acid sequences of seven strains of blue-green algae are compared.

Li, Shou-Dong; Song, Li-Rong; Liu, Yong-Ding; Zhao, Jin-Dong

1998-03-01

189

Activity of cyanobacterial and algal odor compounds found in lake waters on green alga Chlorella pyrenoidosa growth  

Microsoft Academic Search

Volatile organic compounds produced by cyanobacteria and algae in freshwater lakes and contributing to the odour of lakes were tested for their ability to inhibit the growth of the green alga Chlorella pyrenoidosa by the paper disk-agar plate method. Geosmin, ß-cyclocitral, a- and ß-ionones, and geranylacetone exhibited inhibitory activity by diffusion in the 2-5 mg ml-1 range. a- and ß-Ionones

Miyoshi Ikawa; John J. Sasner; James F. Haney

2001-01-01

190

Spectroscopic investigation of ionizing-radiation tolerance of a Chlorophyceae green micro-alga  

NASA Astrophysics Data System (ADS)

Micro-organisms living in extreme environments are captivating in the peculiar survival processes they have developed. Deinococcus radiodurans is probably the most famous radio-resistant bacteria. Similarly, a specific ecosystem has grown in a research reactor storage pool, and has selected organisms which may sustain radiative stress. An original green micro-alga which was never studied for its high tolerance to radiations has been isolated. It is the only autotrophic eukaryote that develops in this pool, although contamination possibilities coming from outside are not unusual. Studying what could explain this irradiation tolerance is consequently very interesting. An integrative study of the effects of irradiation on the micro-algae physiology, metabolism, internal dynamics, and genomics was initiated. In the work presented here, micro-algae were stressed with irradiation doses up to 20 kGy (2 Mrad), and studied by means of nuclear magnetic resonance, looking for modifications in the metabolism, and on the IN13 neutron backscattering instrument at the ILL, looking for both dynamics and structural macromolecular changes in the cells.

Farhi, E.; Rivasseau, C.; Gromova, M.; Compagnon, E.; Marzloff, V.; Ollivier, J.; Boisson, A. M.; Bligny, R.; Natali, F.; Russo, D.; Couté, A.

2008-03-01

191

Determination of Volatile Compounds in Four Commercial Samples of Japanese Green Algae Using Solid Phase Microextraction Gas Chromatography Mass Spectrometry  

PubMed Central

Green algae are of great economic importance. Seaweed is consumed fresh or as seasoning in Japan. The commercial value is determined by quality, color, and flavor and is also strongly influenced by the production area. Our research, based on solid phase microextraction gas chromatography mass spectrometry (SPME-GC-MS), has revealed that volatile compounds differ intensely in the four varieties of commercial green algae. Accordingly, 41 major volatile compounds were identified. Heptadecene was the most abundant compound from Okayama (Ulva prolifera), Tokushima (Ulva prolifera), and Ehime prefecture (Ulva linza). Apocarotenoids, such as ionones, and their derivatives were prominent volatiles in algae from Okayama (Ulva prolifera) and Tokushima prefecture (Ulva prolifera). Volatile, short chained apocarotenoids are among the most potent flavor components and contribute to the flavor of fresh, processed algae, and algae-based products. Benzaldehyde was predominant in seaweed from Shizuoka prefecture (Monostroma nitidum). Multivariant statistical analysis (PCA) enabled simple discrimination of the samples based on their volatile profiles. This work shows the potential of SPME-GC-MS coupled with multivariant analysis to discriminate between samples of different geographical and botanical origins and form the basis for development of authentication methods of green algae products, including seasonings.

Yoshikawa, Keisuke; Fujita, Akira; Mase, Nobuyuki; Watanabe, Naoharu

2014-01-01

192

Iron colloids reduce the bioavailability of phosphorus to the green alga Raphidocelis subcapitata.  

PubMed

Phosphorus (P) is a limiting nutrient in many aquatic systems. The bioavailability of P in natural waters strongly depends on its speciation. In this study, structural properties of iron colloids were determined and related to their effect on P sorption and P bioavailability. The freshwater green alga Raphidocelis subcapitata was exposed to media spiked with radiolabelled (33)PO4, and the uptake of (33)P was monitored for 1 h. The media contained various concentrations of synthetic iron colloids with a size between 10 kDa and 0.45 ?m. The iron colloids were stabilised by natural organic matter. EXAFS spectroscopy showed that these colloids predominantly consisted of ferrihydrite with small amounts of organically complexed Fe. In colloid-free treatments, the P uptake flux by the algae obeyed Michaelis-Menten kinetics. In the presence of iron colloids at 9 or 90 ?M Fe, corresponding to molar P:Fe ratios between 0.02 and 0.17, the truly dissolved P (<10 kDa) was between 4 and 60% of the total dissolved P (<0.45 ?m). These colloids reduced the P uptake flux by R. subcapitata compared to colloid-free treatments at the same total dissolved P concentration. However, the P uptake flux from colloid containing solutions equalled that from colloid-free ones when expressed as truly dissolved P. This demonstrates that colloidal P did not contribute to the P uptake flux. It is concluded that, on the short term, phosphate adsorbed to ferrihydrite colloids is not available to the green alga R. subcapitata. PMID:24797616

Baken, Stijn; Nawara, Sophie; Van Moorleghem, Christoff; Smolders, Erik

2014-08-01

193

Characterization of novel extrachromosomal DNA from giant-celled marine green algae.  

PubMed

Cloned HinfI fragments of the plasmid-like 2.2-kb DNA from the green alga Ernodesmis verticillata (Kützing) Borgesen hybridized solely to single or double bands within the 2.2-kb DNA in genomic Southern blots. Heterologous probes for nuclear and chloroplast genes hybridized only to high-molecular-weight (HMW) DNA. Thus, the low-molecular-weight (LMW) DNA is extrachromosomal and lacks extensive homology to nuclear or chloroplast genes. There was cross-hybridization to LMW DNA from other Caribbean isolates of E. verticillata, but not to that from a Pacific isolate. Under reduced stringency, cross-hybridization to LMW DNA from the related green alga Boergesenia forbesii (Harvey) Feldmann was also observed, suggesting that the LMW DNA may have a common origin and/or function in these algae. Six out of sixteen unique clones hybridized to discrete bands in northern blots, indicating that the LMW DNA may be actively transcribed in vivo. Four of the putatively transcribed clones have regions with significant deduced amino-acid sequence identity to psa and psb gene products, implying that the plasmid-like molecules might have originated from chloroplast DNA. Sequencing data also indicated a high G/C content, as well as the presence of frequent tandem and direct repeats in many of the cloned fragments. Sequencing and restriction analyses suggest that most of the cloned fragments are portions of different DNA molecules, providing evidence that the 2.2-kb extrachromosomal DNA in Ernodesmis is novel in that it represents a fairly heterogeneous population of molecules. PMID:9745023

La Claire, J W; Loudenslager, C M; Zuccarello, G C

1998-09-01

194

Slow algae, fast fungi: exceptionally high nucleotide substitution rate differences between lichenized fungi Omphalina and their symbiotic green algae Coccomyxa.  

PubMed

Omphalina basidiolichens are obligate mutualistic associations of a fungus of the genus Omphalina (the exhabitant) and a unicellular green alga of the genus Coccomyxa (the inhabitant). It has been suggested that symbiotic inhabitants have a lower rate of genetic change compared to exhabitants because the latter are more exposed to abiotic environmental variation and competition from other organisms. In order to test this hypothesis we compared substitution rates in the nuclear ribosomal internal transcribed spacer region (ITS1, 5.8S, ITS2) among fungal species with rates among their respective algal symbionts. To ensure valid comparisons, only taxon pairs (12) with a common evolutionary history were used. On average, substitution rates in the ITS1 portion of Omphalina pairs were 27.5 times higher than rates in the corresponding pairs of Coccomyxa since divergence from their respective ancestor at the base of the Omphalina/Coccomyxa lineage. Substitution rates in the 5.8S and the ITS2 portions were 2.4 and 18.0 times higher, respectively. The highest rate difference (43.0) was found in the ITS1 region. These are, to our knowledge, the highest differences of substitution rates reported for symbiotic organisms. We conclude that the Omphalina model system conforms to the proposed hypothesis of lower substitution rates in the inhabitant, but that the mode of transmission of the inhabitant (vertical versus horizontal) could be a prevailing factor in the regulation of unequal rates of nucleotide substitution between co-evolving symbionts. Our phylogenetic study of Coccomyxa revealed three main lineages within this genus, corresponding to free-living Coccomyxa, individuals isolated from basidiolichens Omphalina and Coccomyxa isolated from ascolichens belonging to the Peltigerales. PMID:14615198

Zoller, Stefan; Lutzoni, François

2003-12-01

195

Light-driven Uptake of Oxygen, Carbon Dioxide, and Bicarbonate by the Green Alga Scenedesmus12  

PubMed Central

Mass spectrometric techniques were used to study several aspects of the competition between O2 and species of inorganic carbon for photosynthetically generated reducing power in the green alga, Scenedesmus. In contrast to wild type, no appreciable light-driven O2 uptake was observed in a mutant lacking photosystem I. It is concluded that the carbon cycle-independent reduction of O2 occurs at the expense of photosystem I-generated reducing equivalents. The commonly observed differences between CO2-grown and air-grown Scenedesmus with respect to CO2 uptake and glycolate formation cannot be ascribed to differences in their capacity for light-driven O2 uptake. There were no intrinsic differences found in O2 uptake capacity between the two physiological types under conditions in which CO2 was saturating or CO2 uptake was inhibited. It was only under CO2-limited conditions that pronounced differences between the two physiological types were observed. This fact suggests that differences in O2 metabolism and sensitivity between the two types really reflect differences in their capacity to assimilate inorganic carbon; in this respect they are analogous to C3 and C4 plants. The hypothesis that air-grown Scenedesmus can assimilate HCO3? by directly monitoring the time course of dissolved CO2, O2 uptake, and O2 evolution in illuminated algal suspensions at alkaline pH was tested. Inasmuch as the measuring technique employed was fast compared to the nonenzymic equilibration of the inorganic carbon species, it was possible to determine the degree to which the CO2 concentration deviated from equilibrium (with the other inorganic carbon species) during the course of illumination. The observed kinetics in air-grown and CO2-grown algae in the presence and absence of carbonic anhydrase, and a comparison of these kinetics with theoretical (computer-generated) time courses, support the idea that air-adapted algae are able to assimilate HCO3? actively at a high rate. The data suggest that these algae preferentially assimilate CO2 and supply the balance of their needs by taking up HCO3?. Since (unlike C4 plants) these algae have no special CO2 pump, and thus have a relatively low affinity for CO2, HCO3? assimilation is the major carbon uptake process at alkaline pH even when the total CO2 is present in millimolar concentrations.

Radmer, Richard; Ollinger, Otto

1980-01-01

196

Host-parasite relationship of the geoduck Panopea abbreviata and the green alga Coccomyxa parasitica in the Argentinean Patagonian coast.  

PubMed

The association of the geoduck Panopea abbreviata and the green alga Coccomyxa parasitica is described. The identity of the green alga was confirmed by molecular studies; the alga was found within the hemocytes that infiltrate the connective tissue of the geoduck siphons. Cytological characteristics of hemocytes were not altered by algal infection; very often the algae were seen enveloped by a digestive vacuole within the hemocyte cytoplasm, evidencing diverse degrees of resorption. Connective cells of siphons were rarely infected by C. parasitica. The mean prevalence of C. parasitica was higher (82%) in San Matías Gulf (42°00'S, 65°05'W) than in San José Gulf (45%) (40°32'S, 64°02'W); except for spring, when the two locations showed no differences in prevalences (80%). Independently of location, season and host size, infected geoducks showed lower condition index values than uninfected ones. Regarding other bivalve species, only one specimen of the razor clam Ensis macha was found infected, and none of the oysters Ostrea puelchana and Pododesmus rudis and scallop Aequipecten tehuelchus was parasitized by the green alga. PMID:20670631

Vázquez, Nuria; Rodríguez, Francisco; Ituarte, Cristián; Klaich, Javier; Cremonte, Florencia

2010-11-01

197

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

PubMed Central

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. Results We studied the impact of selenium compounds on the green chlorococcal alga Scenedesmus quadricauda. Both the dose and chemical forms of Se were critical factors in the cellular response. Se toxicity increased in cultures grown under sulfur deficient conditions. We selected three strains of Scenedesmus quadricauda specifically resistant to high concentrations of inorganic selenium added as selenite (Na2SeO3) – strain SeIV, selenate (Na2SeO4) – strain SeVI or both – strain SeIV+VI. The total amount of Se and selenomethionine in biomass increased with increasing concentration of Se in the culturing media. The selenomethionine made up 30–40% of the total Se in biomass. In both the wild type and Se-resistant strains, the activity of thioredoxin reductase, increased rapidly in the presence of the form of selenium for which the given algal strain was not resistant. Conclusion The selenium effect on the green alga Scenedesmus quadricauda was not only dose dependent, but the chemical form of the element was also crucial. With sulfur deficiency, the selenium toxicity increases, indicating interference of Se with sulfur metabolism. The amount of selenium and SeMet in algal biomass was dependent on both the type of compound and its dose. The activity of thioredoxin reductase was affected by selenium treatment in dose-dependent and toxic-dependent manner. The findings implied that the increase in TR activity in algal cells was a stress response to selenium cytotoxicity. Our study provides a new insight into the impact of selenium on green algae, especially with regard to its toxicity and bioaccumulation.

Umysova, Dasa; Vitova, Milada; Douskova, Irena; Bisova, Katerina; Hlavova, Monika; Cizkova, Maria; Machat, Jiri; Doucha, Jiri; Zachleder, Vilem

2009-01-01

198

Comparative effects of the blue green algae Nodularia spumigena and a lysed extract on detoxification and antioxidant enzymes in the green lipped mussel ( Perna viridis)  

Microsoft Academic Search

Nodularia spumigena periodically proliferates to cause toxic algal blooms with some aquatic animals enduring and consuming high densities of the blue green algae or toxic lysis. N. spumigena contains toxic compounds such as nodularin and lipopolysaccharides. This current work investigates physiological effects of exposure from bloom conditions of N. spumigena cells and a post-bloom lysis. Biochemical and antioxidative biomarkers were

Warren R. Davies; William H. L. Siu; Ralph W. Jack; Rudolf S. S. Wu; Paul K. S. Lam; Dayanthi Nugegoda

2005-01-01

199

Bioaccumulation of Cr(III) ions by Blue Green alga Spirulina sp. Part I. A Comparison with Biosorption  

Microsoft Academic Search

The paper presents the results of studies on kinetics and equilibrium of bioaccumulati on process of Cr(III) ions by blue-green alga Spirulina sp. Bioaccumulation was described as the process that consists of two stages, passive (identical with biosorption) and active (accumulation inside the cells). The passive stage (similarly as biosorption itself) was found to be quick process and the subsequent

Katarzyna Chojnacka

200

Reproductive Strategies of Marine Green Algae: the Evolution of Slight Anisogamy and the Environmental Conditions of Habitats  

Microsoft Academic Search

In marine green algae, isogamous or slightly aniso gamous species are taxonomically widespread. They produce positively phototactic gametes with phototactic devices including an eye-spot in both sex es. We developed a new numerical simulator of gamete behavior using C++ and pseudo-parallelization methods to elucidate potential advantages of phototaxis. In put parameters were set based on experimental data. Each gamete swimming

Tatsuya Togashi; Tatsuo Miyazaki; Jin Yoshimura; John L. Bartelt; Paul Alan Cox

201

Absence of the Pigments of Photosystem II of Photosynthesis in Heterocysts of a Blue-Green Alga  

Microsoft Academic Search

ALL filamentous blue-green algae capable of fixing elementary nitrogen have heterocysts. Stewart et al.1 have strong evidence that these differentiated cells are the sites of nitrogen fixation. They did not, however, show that photosystem II, responsible for the evolution of molecular oxygen (O2), is not functional in heterocysts. Because high oxygen tension inhibits nitrogen fixation, heterocysts should not possess the

Joseph Thomas

1970-01-01

202

Deformation of isolated rat hepatocytes by a peptide hepatotoxin from the blue-green alga Microcystis aeruginosa  

Microsoft Academic Search

The effect of the peptide hepatotoxin from the bloom-forming blue-green alga Microcystis aeruginosa was investigated on isolated rat hepatocytes. When toxin was added to hepatocyte suspensions it produced deformation of the cells, as shown by scanning electron microscopy. This was apparent within 5 min of addition of toxin to the cells and the response was dose dependent: 30 ng of

M. T. Runnegar; I. R. Falconer; J. Silver

1981-01-01

203

Physical map and gene organization of the mitochondrial genome from the unicellular green alga Platymonas (Tetraselmis) subcordiformis (Prasinophyceae)  

Microsoft Academic Search

the entire mitochondrial genome (mt genome) of the unicellular green alga Platymonas subcordiformis (synonym Tetraselmis subcordiformis; Prasinophyceae) was cloned and a physical map for the four restriction enzymes Hind III, Eco RI, Bgl II and Xba I was constructed. The mt genome of P. subcordiformis is a 42.8 kb circular molecule, coding for at least 23 genes. Hybridization and sequence

Ulrike Kessler; Klaus Zetsche

1995-01-01

204

The uptake of Manganese54 by green algae (Protococcoidal chlorella), Daphnia magna, and fathead minnows (Pimephales promelas)  

Microsoft Academic Search

Concentration factors (CF) of 54Mn for three aquatic species: green algae (Protococcoidal chlorella), Daphnia magna, and fathead minnows (Pimephales promelas) were determined following direct exposure to the isotope in solution. The maximum accumulation (CF = 911) in P. chlorella was reached at 48 hours of exposure; the maximum uptake (CF = 65) in Daphnia was reached at 8 hours of

G. M. Kwasnik; R. J. Vetter; G. J. Atchison

1978-01-01

205

Growth and Protein Production in Selected Laboratory Cultures of Blue-Green Algae Grown in 'Tilapia' Wastewaters.  

National Technical Information Service (NTIS)

The basic aim of the study was to observe and analyze a photosynthetic mariculture system utilizing the blue-green algae Arthrospira Platensis and Spirulina major grown in fish wastewater as the algal medium. The objectives were to provide data for critic...

C. F. Rhyne L. Crump P. Jordan

1985-01-01

206

Novel Antibacterial Proteins from the Microbial Communities Associated with the Sponge Cymbastela concentrica and the Green Alga Ulva australis? †  

PubMed Central

The functional metagenomic screening of the microbial communities associated with a temperate marine sponge and a green alga identified three novel hydrolytic enzymes with antibacterial activities. The results suggest that uncultured alpha- and gammaproteobacteria contain new classes of proteins that may be a source of antibacterial agents.

Yung, Pui Yi; Burke, Catherine; Lewis, Matt; Kjelleberg, Staffan; Thomas, Torsten

2011-01-01

207

Food selectivity of the herbivore Daphnia magna (Cladocera) and its impact on competition outcome between two freshwater green algae  

Microsoft Academic Search

Freshwater green algae, Chlorella, have heavy cell walls and their size usually exceeds the lower limits of limb size of herbivorous Daphnia (Cladocera). According to the optimal foraging theory, we speculated that Daphnia would graze more exposed and relatively large Clamydomonas rather than Chlorella, and this process would lead to small-sized Chlorella becoming a superior competitor in the presence of

Xu Wang Yin; Peng Fei Liu; Sha Sha Zhu; Xiao Xia Chen

2010-01-01

208

Spectral dependence of the inhibition of photosynthesis under simulated global radiation in the unicellular green alga Dunaliella salina  

Microsoft Academic Search

The inhibition of photosynthesis after exposure to simulated solar radiation has been investigated in the marine green alga Dunaliella salina by monitoring the chlorophyll fluorescence parameter, ?F\\/Fm?, and the maximum light utilization efficiency for oxygen production. 40 different irradiation regimes have been applied by combining two different levels of UV radiation with two different levels of photosynthetically active radiation (PAR),

F. Ghetti; H. Herrmann; D.-P. Häder; H. K. Seidlitz

1999-01-01

209

Growth of Filamentous Blue-Green Algae at High Temperatures: A Source of Biomass for Renewable Fuels.  

National Technical Information Service (NTIS)

The growth of filamentous blue-green algae (FBGA) at high temperatures in outdoor, shallow solar ponds is being investigated. The temperature of the 60-m exp 2 ponds can be controlled to an average temperature of 45 exp 0 C. The growth of FBGA at high tem...

H. Timourian R. L. Ward T. W. Jeffries

1977-01-01

210

Desiccation-induced non-radiative dissipation in isolated green lichen algae.  

PubMed

Lichens are able to tolerate almost complete desiccation and can quickly resume metabolic activity after rehydration. In the desiccated state, photosynthesis is completely blocked and absorbed excitation energy cannot be used for electron transport, leading to a potential strong vulnerability for high light damage. Although desiccation and high insolation often occur simultaneously and many lichens colonize exposed habitats, these organisms show surprisingly little photodamage. In the desiccated state, variable chlorophyll fluorescence is lost, indicating a suspension of charge separation in photosystem II. At the same time, basal fluorescence (F (0)) is strongly quenched, which has been interpreted as an indication for high photoprotective non-radiative dissipation (NRD) of absorbed excitation energy. In an attempt to provide evidence for a photoprotective function of NRD in the desiccated state, isolated green lichen algae of the species Coccomyxa sp. and Trebouxia asymmetrica were used as experimental system. In contrast to experiments with intact lichens this system provided high reproducibility of the data without major optical artifacts on desiccation. The presence of 5 mM trehalose during desiccation had no effect but culture of the algae in seawater enhanced F (0) quenching in T. asymmetrica together with a reduced depression of F (V)/F (M) after high light treatment. While this effect could not be induced using artificial seawater medium lacking trace elements, the addition of ZnCl(2) and NaI in small amounts to the normal growth medium led to qualitatively and quantitatively identical results as with pure seawater. It is concluded that NRD indicated by F (0) quenching is photoprotective. The formation of NRD in lichen algae is apparently partially dependent on the presence of specific micronutrients. PMID:22833109

Wieners, Paul Christian; Mudimu, Opayi; Bilger, Wolfgang

2012-09-01

211

Carbon Oxysulfide Inhibition of the CO2-Concentrating Process of Unicellular Green Algae 1  

PubMed Central

Carbonyl sulfide (COS), a substrate for carbonic anhydrase, inhibited alkalization of the medium, O2 evolution, dissolved inorganic carbon accumulation, and photosynthetic CO2 fixation at pH 7 or higher by five species of unicellular green algae that had been air-adapted for forming a CO2-concentrating process. This COS inhibition can be attributed to inhibition of external HCO3? conversion to CO2 and OH? by the carbonic anhydrase component of an active CO2 pump. At a low pH of 5 to 6, COS stimulated O2 evolution during photosynthesis by algae with low CO2 in the media without alkalization of the media. This is attributed to some COS hydrolysis by carbonic anhydrase to CO2. Although COS had less effect on HCO3? accumulation at pH 9 by a HCO3? pump in Scenedesmus, COS reduced O2 evolution probably by inhibiting internal carbonic anhydrases. Because COS is hydrolyzed to CO2 and H2S, its inhibition of the CO2 pump activity and photosynthesis is not accurate, when measured by O2 evolution, by NaH14CO3 accumulation, or by 14CO2 fixation.

Goyal, Arun; Shiraiwa, Yoshihiro; Tolbert, N. Edward

1992-01-01

212

Effect of aluminum and zinc on enzyme activities in the green Alga Selenastrum capricorutum  

SciTech Connect

Acid rain produced by atmospheric pollution may decrease the pH value of water and increase the availability and potential toxicity of metals in water which have detrimental effects on aquatic organism, including algae, the important component of the primary production, and, thus, the entire aquatic food chain. Recent reviews of the effects of acid rain on freshwater ecosystems have emphasized research interest in soluble trivalent aluminum, although Al is rated low among trace metals in biological importance. On the other hand, zinc is an important trace element for the growth of phytoplankton and the cofactor of some enzymes. The growth response and tolerance of different species of algae to Al and Zn have been reported by Whitton who showed that algal growth would be stimulated by lower levels of the metals and totally inhibited by higher levels. These is little information, however, on the effect of Al on biochemical processes in aquatic organisms. This study investigates the influence of aluminum and zinc on several physioclogical processes in S. capricournutum, a common species of green algal in lake water. Algal growth (dry weight), ATP levels and the activities of several enzymes in the algal cells were measured after the treatment with various concentrations of Al and Zn in culture medium. Special attention is given to the relation between the enzymatic response and algal growth. 15 refs., 2 figs., 1 tab.

Kong, F.X.; Chen, Y. [Nanjing Univ. (China)

1995-11-01

213

The influence of nitrogen on heterocyst production in blue-green algae  

USGS Publications Warehouse

A series of experiments on heterocyst production in Anabaena variabilis provides some strong indirect evidence for the role of heterocysts in nitrogen fixation. Of the algae tested (Anabaena variabilis, A. inaequalis, A. cylindrica, A. flos-aquae, Tolypothrix distorta, Gloeotrichia echinulata, Aphanizomenon flos-aquae, Oscillatoria sp., and Microcystis aeruginosa), only those with heterocysts grew in a nitrate-free medium. Growth in the nitrate-free medium was accompanied by an increase in heterocysts. Heterocyst formation in A. variabilis was evident 24 hr after transfer from a nitrate-containing to a nitrate-free medium. The number of heterocysts was altered by changes in the nitrogen source. Numbers were lowest when NH4-N was used as a nitrogen source and highest when nitrogen (N2-N) was derived from the atmosphere. Heterocyst numbers could also be regulated by controlling the concentration of NO3-N in the medium. Heterocyst production depended on the absence of combined nitrogen and the presence of phosphate. Data are presented on the occurrence of blue-green algae (with heterocysts) in Lake Erie and the environmental conditions apparently necessary for them to become dominant.

Ogawa, Roann E.; Carr, John F.

1969-01-01

214

Toxic effects of organic solvents on the growth of blue-green algae  

SciTech Connect

Relatively few reports have been published on the comparative toxicity of solvents towards test organisms, and these deal primarily with fish and aquatic invertebrates. Information for microbial systems are more limited with some data available for algae and slightly more for fungi. Aside from direct toxic effects of their own, solvents can interact synergistically and antagonistically with the toxicant in solution. This problem has been well documented with pesticides, and a procedure has been developed to identify and eliminate these effects from bioassays. The first step in choosing a solvent for use in microbial bioassays should be a detailed screening to identify solvents with inherently low toxicity to the test organism, followed by an interaction study to choose the best concentration to use. The purpose of the present study was to compare the inhibitory effects of six solvents commonly used in pesticide bioassays towards five species of blue-green algae (cyanobacteria), in order to identify solvents with low toxicity for use in bioassays.

Stratton, G.W.

1987-06-01

215

Two light-activated conductances in the eye of the green alga Volvox carteri.  

PubMed Central

Photoreceptor currents of the multicellular green alga Volvox carteri were analyzed using a dissolver mutant. The photocurrents are restricted to the eyespot region of somatic cells. Photocurrents are detectable from intact cells and excised eyes. The rhodopsin action spectrum suggests that the currents are induced by Volvox rhodopsin. Flash-induced photocurrents are a composition of a fast Ca2+-carried current (PF) and a slower current (PS), which is carried by H+. PF is a high-intensity response that appears with a delay of less than 50 micros after flash. The stimulus-response curve of its initial rise is fit by a single exponential and parallels the rhodopsin bleaching. These two observations suggest that the responsible channel is closely connected to the rhodopsin, both forming a tight complex. At low flash energies PS is dominating. The current delay increases up to 10 ms, and the PS amplitude saturates when only a few percent of the rhodopsin is bleached. The data are in favor of a second signaling system, which includes a signal transducer mediating between rhodopsin and the channel. We present a model of how different modes of signal transduction are accomplished in this alga under different light conditions.

Braun, F J; Hegemann, P

1999-01-01

216

Sulfated Oligosaccharides Mediate the Interaction between a Marine Red Alga and Its Green Algal Pathogenic Endophyte.  

PubMed Central

The endophytic green alga Acrochaete operculata completely colonizes the sporophytes of the red alga Chondrus crispus; however, it does not penetrate beyond the outer cell layers of the gametophytes. Given that the life cycle phases of C. crispus differ in the sulfation pattern of their extracellular matrix carrageenans, we investigated whether carra-geenan fragments could modulate parasite virulence. lambda-Carrageenan oligosaccharides induced release of H(2)O(2), stimulated protein synthesis, increased carrageenolytic activity, and induced specific polypeptides in the pathogen, resulting in a marked increase in pathogenicity. In contrast, kappa-carrageenan oligosaccharides did not induce a marked release of H(2)O(2) from A. operculata but hindered amino acid uptake and enhanced their recognition by the host, resulting in a reduced virulence. Moreover, C. crispus life cycle phases were shown to behave differently in their response to challenge with cell-free extracts of A. operculata. Gametophytes exhibited a large burst of H(2)O(2), whereas only low levels were released from the sporophytes.

Bouarab, K; Potin, P; Correa, J; Kloareg, B

1999-01-01

217

Rapid biotransformation of arsenate into oxo-arsenosugars by a freshwater unicellular green alga, Chlamydomonas reinhardtii.  

PubMed

We examined the short-term metabolic processes of arsenate for 24 h in a freshwater unicellular green alga, Chlamydomonas reinhardtii wild-type strain CC-125. The arsenic species in the algal extracts were identified by high-performance liquid chromatography/inductively coupled plasma mass spectrometry after water extraction using a sonicator. Speciation analyses of arsenic showed that the levels of arsenite, arsenate, and methylarsonic acid in the cells rapidly increased for 30 min to 1 h, and those of dimethylarsinic acid and oxo-arsenosugar-glycerol also tended to increase continuously for 24 h, while that of oxo-arsenosugar-phosphate was quite low and fluctuated throughout the experiment. These results indicate that this alga can rapidly biotransform arsenate into oxo-arsenosugar-glycerol for at least 10 min and then oxo-arsenosugar-phosphate through both reduction of incorporated arsenate to arsenite and methylation of arsenite and/or arsenate retained in the cells to dimethylarsinic acid via methylarsonic acid as an possible intermediate. PMID:21389618

Miyashita, Shinichi; Fujiwara, Shoko; Tsuzuki, Mikio; Kaise, Toshikazu

2011-01-01

218

[Glutamate dehydrogenases of unicellular green algae: effects of nitrate and ammonium in vivo].  

PubMed

The constitution and control by the inorganic nitrogen source of glutamate dehydrogenases of some unicellular green algae have been studied. The Ankistrodesmus braunii and Scenedesmus obliquus cells contain two different glutamate dehydrogenases, one of which is NADP-specific, the other is active with both NAD and NADP. Their synthesis does not depend on the nitrogen source. The activity of NADP-specific glutamate dehydrogenase increases sharply during nitrogen starvation. In Chlorella pyrenoidosa 82 and Ch. ellipsoidea only one constitutive double specific glutamate dehydrogenase is observed. Its activity does not change depending on the nitrogen nutrition conditions. In the cells of the thermophylic Chlorella strain Chlorella sp. K. ammomium induces a de novo synthesis of NADP-specific glutamate dehydrogenase in addition to the constitutive double specific glutamate dehydrogenase. Thus, the algae tested contain constitutive double specific glutamate dehydrogenase. The NADP-specific enzyme is absent in two Chlorella strains, is constitutive in A. braunii and S. obliquus, and is ammonium-inducible in three thermophylic Chlorella strains. PMID:25679

Shatilov, V R; Sofbin, A V; Kasatkina, T I; Zabrodina, T M; Vladimirova, M G; Kretovich, V L

1978-02-01

219

Green synthesis of silver nanoparticles using polysaccharides extracted from marine macro algae.  

PubMed

Green synthesis of nanoparticles that have environmentally acceptable solvent systems and eco-friendly reducing agents is of great importance. The aim of this work was to synthesis of silver nanoparticles (AgNPs) using water soluble polysaccharides extracted from four marine macro-algae, namely, Pterocladia capillacae (Pc), Jania rubins (Jr), Ulva faciata (Uf), and Colpmenia sinusa (Cs) as reducing agents for silver ions as well as stabilizing agents for the synthesized AgNPs. The formed Ag-NPs have been confirmed by UV-Vis spectroscopy, FTIR analysis and TEM. The resultant Ag-NPs colloidal solutions were applied to cotton fabrics in presence and absence of citric acid (CA) or a binder (B). The antimicrobial activity of the treated fabrics was evaluated. The results revealed that the antimicrobial activity depends on type of the fabric treatment, size of the synthesized Ag-NPs and the algal species used for polysaccharides extraction. PMID:23768580

El-Rafie, H M; El-Rafie, M H; Zahran, M K

2013-07-25

220

Seawater-based methane production from blue-green algae biomass by marine bacteria coculture  

SciTech Connect

Marine-enriched culture NKM 004 produced methane from various carbohydrates, but methane production was inhibited by sulfate and acetate accumulated in the medium. On the other hand, marine methanogenic bacterium NKM 006 produced methane from acetate and methyltrophic substrates, and methane production was not inhibited by sulfate. The mixture of NKM 004 and NKM 006 continuously produced methane from marine blue-green algae Dermocarpa species NKBG 102B at 54 ..mu..mol/L medium/h for 200 h and the dry weight of the algal biomass was decreased to 25% of the initial weight in the natural seawater. Conversion of algal carbohydrate (glucose equivalent) to methane was 65%. Results indicate that this system is promising for methane production based on seawater and solar energy.

Matsunaga, T.; Izumida, H.

1984-01-01

221

Mössbauer study of cobalt and iron in the cyanobacterium (blue green alga)  

NASA Astrophysics Data System (ADS)

Mössbauer emission and absorption studies have been performed on cobalt and iron in the cyanobacterium (blue-green alga). The Mössbauer spectrum of the cyanobacterium cultivated with57Co is decomposed into two doublets. The parameters of the major doublet are in good agreement with those of cyanocobalamin (vitamin B12) labeled with57Co. The other minor doublet has parameters close to those of Fe(II) coordinated with six nitrogen atoms. These suggest that cobalt is used for the biosynthesis of vitamin B12 or its analogs in the cyanobacterium. The spectra of the cyanobacterium grown with57Fe show that iron is in the high-spin trivalent state and possibly in the form of ferritin, iron storage protein.

Ambe, Shizuko

1990-07-01

222

Viruses of eukaryotic green algae; Progress report, June 20, 1990--July 1, 1991  

SciTech Connect

Many large polyhedral, dsDNA containing (ca. 330 kb), plaque forming viruses which infect a unicellular, eukaryotic, chlorella-like green alga have been isolated and characterized. The plaque assay, the ability to synchronously infect the host, the short life cycle, and the ability of the viruses to undergo homologous recombination make them excellent model systems for studying many plant cell functions in the manner that bacterial and animal viruses have been used to study bacterial and animal cell functions. These viruses have several unique features including: (1) coding for DNA methyltransferase and site-specific (restriction) endonucleases and (2) unlike other viruses, these viruses appear to code for the enzymes involved in the glycosylation of their glycoproteins.

Van Etten, J.L.

1991-12-31

223

Assessment of blue-green algae in substantially reducing nitrogen fertilizer requirements for biomass fuel crops  

SciTech Connect

Laboratory, mass culture, and field studies are being undertaken in order to assess the potential of using blue-green algae (cyanobacteria) as nitrogen biofertilizers on irrigated ground. Of seven candidate strains, two were chosen for application to replicated field plots sown to field corn and the basis of laboratory-scale soil tray experiments and ease of semi-continuous 8000 l culture. Chosen were Anabaena BM-165, isolated from a local soil and Tolypothrix tenuis, imported from India. Using the acetylene reduction method, Anabaena is estimated from laboratory soil experiments to be able to fix from 30 to 62 kg N/ha/y, and has been mass cultured to a density of 1527 mg dry wt/l. T. tenuis is estimated from laboratory experiments to be able to fix from 27 to 65 kg N/ha/y, and has been mass cultured to a density of 1630 mg dry wt/l.

Anderson, D.B.; Molten, P.M.; Metting, B.

1981-07-01

224

Purification and characterisation of an intracellular carbonic anhydrase from the unicellular green alga Coccomyxa.  

PubMed

An intracellular carbonic anhydrase (CA; EC 4.2.1.1) was purified and characterised from the unicellular green alga Coccomyxa sp. Initial studies showed that cultured Coccomyxa cells contain an intracellular CA activity around 100 times higher than that measured in high-CO2-grown cells of Chlamydomonas reinhardtii CW 92. Purification of a protein extract containing the CA activity was carried out using ammonium-sulphate precipitation followed by anion-exchange chromatography. Proteins were then separated by native (non-dissociating) polyacrylamide gel electrophoresis, with each individual protein band excised and assayed for CA activity. Measurements revealed CA activity associated with two discrete protein bands with similar molecular masses of 80 +/- 5 kDa. Dissociation by denaturing polyacrylamide gel electrophoresis showed that both proteins contained a single polypeptide of 26 kDa, suggesting that each 80-kDa native protein was a homogeneous trimer. Isoelectric focusing of the 80-kDa proteins also produced a single protein band at a pH of 6.5. Inhibition studies on the purified CA extract showed that 50% inhibition of CA activity was obtained using 1 microM azetazolamide. Polyclonal antibodies against the 26-kDa CA were produced and shown to have a high specific binding to a single polypeptide in soluble protein extracts from Coccomyxa cells. The same antiserum, however, failed to cross-react with soluble proteins isolated from two different species of green algae, Chlamydomonas reinhardtii and Chlorella vulgaris. Correspondingly, antisera directed against pea chloroplastic CA, extracellular CA from C. reinhardtii and human CAII, showed no cross-hybridisation to the 26-kDa polypeptide in Coccomyxa.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7766041

Hiltonen, T; Karlsson, J; Palmqvist, K; Clarke, A K; Samuelsson, G

1995-01-01

225

A multidisciplinary study of iron transport and storage in the marine green alga Tetraselmis suecica.  

PubMed

The iron uptake and storage systems of terrestrial/higher plants are now reasonably well understood with two basic strategies being distinguished: strategy I involves the induction of a Fe(III)-chelate reductase (ferrireductase) along with Fe(II) or Fe(III) transporter proteins while strategy II plants have evolved sophisticated systems based on high-affinity, iron specific, binding compounds called phytosiderophores. In contrast, there is little knowledge about the corresponding systems in marine, plant-like lineages. Herein we report a study of the iron uptake and storage mechanisms in the green alga Tetraselmis suecica. Short term radio-iron uptake studies indicate that iron is taken up by Tetraselmis in a time and concentration dependent manner consistent with an active transport process. Based on inhibitor and other studies it appears that a reductive-oxidative pathway such as that found in yeast and the green alga Chlamydomonas reinhardtii is likely. Upon long term exposure to (57)Fe we have been able, using a combination of Mössbauer and X-ray absorption spectroscopies, to identify three metabolites. The first exhibits Mössbauer parameters typical of a [Fe(4)S(4)](2+) cluster and which accounts for approximately 10% of the total intracellular iron pool. The second displays a spectrum typical of a [Fe(II)O(6)] system accounting for approximately 2% of the total pool. The largest component (ca. 85+%) consists of polymeric iron-oxo mineral species with parameters between that of the crystalline ferrihydrite core of animal ferritins and the amorphous hydrated ferric phosphate of bacterial and plant ferritins. PMID:23041362

Hartnett, Andrej; Böttger, Lars H; Matzanke, Berthold F; Carrano, Carl J

2012-11-01

226

Pectin Metabolism and Assembly in the Cell Wall of the Charophyte Green Alga Penium margaritaceum.  

PubMed

The pectin polymer homogalacturonan (HG) is a major component of land plant cell walls and is especially abundant in the middle lamella. Current models suggest that HG is deposited into the wall as a highly methylesterified polymer, demethylesterified by pectin methylesterase enzymes and cross-linked by calcium ions to form a gel. However, this idea is based largely on indirect evidence and in vitro studies. We took advantage of the wall architecture of the unicellular alga Penium margaritaceum, which forms an elaborate calcium cross-linked HG-rich lattice on its cell surface, to test this model and other aspects of pectin dynamics. Studies of live cells and microscopic imaging of wall domains confirmed that the degree of methylesterification and sufficient levels of calcium are critical for lattice formation in vivo. Pectinase treatments of live cells and immunological studies suggested the presence of another class of pectin polymer, rhamnogalacturonan I, and indicated its colocalization and structural association with HG. Carbohydrate microarray analysis of the walls of P. margaritaceum, Physcomitrella patens, and Arabidopsis (Arabidopsis thaliana) further suggested the conservation of pectin organization and interpolymer associations in the walls of green plants. The individual constituent HG polymers also have a similar size and branched structure to those of embryophytes. The HG-rich lattice of P. margaritaceum, a member of the charophyte green algae, the immediate ancestors of land plants, was shown to be important for cell adhesion. Therefore, the calcium-HG gel at the cell surface may represent an early evolutionary innovation that paved the way for an adhesive middle lamella in multicellular land plants. PMID:24652345

Domozych, David S; Sřrensen, Iben; Popper, Zoë A; Ochs, Julie; Andreas, Amanda; Fangel, Jonatan U; Pielach, Anna; Sacks, Carly; Brechka, Hannah; Ruisi-Besares, Pia; Willats, William G T; Rose, Jocelyn K C

2014-05-01

227

Phylogenetic and morphological characterization of the green alga infesting the horse mussel Modiolus modiolus from Vityaz Bay (Peter the Great Bay, Sea of Japan).  

PubMed

In this work, the ultrastructural features and taxonomic position of the green microalga infesting the horse mussel Modiolus modiolus from the north-western Pacific (Vityaz Bay, Peter the Great Bay, Sea of Japan) are reported. Mussels were collected monthly from May to September of 2009. In different months, the prevalence of mussels with green tissues was 16.6-62.5% (mean 43%). The most affected organs were the mantle, digestive gland and gonad. Histological analysis revealed severe infiltration of the connective tissue by hemocytes containing the alga cells. Electron microscopy showed that the alga was morphologically similar to the green algae from the genus Coccomyxa (Chlorophyta: Chlorococcales). Two new primers were designed to generate partial small subunit (SSU) rRNA sequences of the green alga from M. modiolus. Phylogenetic analysis based on the comparison of the SSU rRNA sequences of the trebouxiophyceans confirmed an affiliation of the green alga with the genus Coccomyxa. The sequence (1296 bases) of the green alga from M. modiolus was most closely related to the sequence CPCC 508 (AM981206) (identity 100%), obtained from an acid-tolerant, free-living chlorophyte microalga Coccomyxa sp. and to the sequences EU127470 (identity 99.3%) and EU127471 (identity 99.7%) of the green alga, presumably the true Coccomyxa parasitica, infecting the blue mussel Mytilus edulis from the Flensburg Fjord (North Atlantic). PMID:22902969

Syasina, I G; Kukhlevsky, A D; Kovaleva, A L; Vaschenko, M A

2012-10-01

228

From algae to angiosperms-inferring the phylogeny of green plants (Viridiplantae) from 360 plastid genomes  

PubMed Central

Background Next-generation sequencing has provided a wealth of plastid genome sequence data from an increasingly diverse set of green plants (Viridiplantae). Although these data have helped resolve the phylogeny of numerous clades (e.g., green algae, angiosperms, and gymnosperms), their utility for inferring relationships across all green plants is uncertain. Viridiplantae originated 700-1500 million years ago and may comprise as many as 500,000 species. This clade represents a major source of photosynthetic carbon and contains an immense diversity of life forms, including some of the smallest and largest eukaryotes. Here we explore the limits and challenges of inferring a comprehensive green plant phylogeny from available complete or nearly complete plastid genome sequence data. Results We assembled protein-coding sequence data for 78 genes from 360 diverse green plant taxa with complete or nearly complete plastid genome sequences available from GenBank. Phylogenetic analyses of the plastid data recovered well-supported backbone relationships and strong support for relationships that were not observed in previous analyses of major subclades within Viridiplantae. However, there also is evidence of systematic error in some analyses. In several instances we obtained strongly supported but conflicting topologies from analyses of nucleotides versus amino acid characters, and the considerable variation in GC content among lineages and within single genomes affected the phylogenetic placement of several taxa. Conclusions Analyses of the plastid sequence data recovered a strongly supported framework of relationships for green plants. This framework includes: i) the placement of Zygnematophyceace as sister to land plants (Embryophyta), ii) a clade of extant gymnosperms (Acrogymnospermae) with cycads?+?Ginkgo sister to remaining extant gymnosperms and with gnetophytes (Gnetophyta) sister to non-Pinaceae conifers (Gnecup trees), and iii) within the monilophyte clade (Monilophyta), Equisetales?+?Psilotales are sister to Marattiales?+?leptosporangiate ferns. Our analyses also highlight the challenges of using plastid genome sequences in deep-level phylogenomic analyses, and we provide suggestions for future analyses that will likely incorporate plastid genome sequence data for thousands of species. We particularly emphasize the importance of exploring the effects of different partitioning and character coding strategies.

2014-01-01

229

Composition, uniqueness and variability of the epiphytic bacterial community of the green alga Ulva australis  

PubMed Central

Green Ulvacean marine macroalgae are distributed worldwide in coastal tidal and subtidal ecosystems. As for many living surfaces in the marine environment, little is known concerning the epiphytic bacterial biofilm communities that inhabit algal surfaces. This study reports on the largest published libraries of near full-length 16S rRNA genes from a marine algal surface (5293 sequences from six samples) allowing for an in-depth assessment of the diversity and phylogenetic profile of the bacterial community on a green Ulvacean alga. Large 16S rRNA gene libraries of surrounding seawater were also used to determine the uniqueness of this bacterial community. The surface of Ulva australis is dominated by sequences of Alphaproteobacteria and the Bacteroidetes, especially within the Rhodobacteriaceae, Sphingomonadaceae, Flavobacteriaceae and Sapropiraceae families. Seawater libraries were also dominated by Alphaproteobacteria and Bacteroidetes sequences, but were shown to be clearly distinct from U. australis libraries through the clustering of sequences into operational taxonomic units and Bray–Curtis similarity analysis. Almost no similarity was observed between these two environments at the species level, and only minor similarity was observed at levels of sequence clustering representing clades of bacteria within family and genus taxonomic groups. Variability between libraries of U. australis was relatively high, and a consistent sub-population of bacterial species was not detected. The competitive lottery model, originally derived to explain diversity in coral reef fishes, may explain the pattern of colonization of this algal surface.

Burke, Catherine; Thomas, Torsten; Lewis, Matt; Steinberg, Peter; Kjelleberg, Staffan

2011-01-01

230

Photosynthetic and growth responses of three freshwater algae to phosphorus limitation and daylength  

Microsoft Academic Search

SUMMARY 1. Three common species of freshwater phytoplankton, the diatom Nitzschia sp., green alga Sphaerocystis schroeteri and cyanobacterium Phormidium luridum, were grown under contrasting daylengths (18 : 6 h light : dark cycles (LD) versus 6 : 18 h LD) and phosphorus (P) regimes (P-sufficient versus 1 lM M P). The rates of growth and photosyn- thesis, as well as

ELENA L ITCHMAN; D ANIEL S TEINER; P ETER B OSSARD

2003-01-01

231

Light-dependent conformational change of neoxanthin in a siphonous green alga, Codium intricatum, revealed by Raman spectroscopy.  

PubMed

Siphonous green algae, a type of deep-sea green algae, appear olive drab and utilize blue-green light for photosynthesis. A siphonous green alga, Codium (C.) intricatum, was isolated from Okinawa prefecture in Japan, and a clonal algal culture in filamentous form was established. The major light-harvesting antenna was analogous to the trimeric LHCII found in higher plants, but the C. intricatum complex contained an unusual carbonyl carotenoid siphonaxanthin. Culture conditions were optimized to achieve high siphonaxanthin content in intact lyophilized filamentous bodies. Interestingly, the carotenoid composition was different when cultured under high irradiance: all-trans neoxanthin was accumulated in addition to the normal 9'-cis form in whole cell extract. Resonance Raman spectra of intact filamentous bodies, cultured under high- and low-light conditions, confirmed the accumulation of all-trans neoxanthin under high irradiance conditions. A plausible function of the presence of all-trans neoxanthin will be discussed in relation to the regulation against high light stress. PMID:24861896

Uragami, Chiasa; Galzerano, Denise; Gall, Andrew; Shigematsu, Yusuke; Meisterhans, Maďwen; Oka, Naohiro; Iha, Masahiko; Fujii, Ritsuko; Robert, Bruno; Hashimoto, Hideki

2014-07-01

232

Uranium accumulation and toxicity in the green alga Chlamydomonas reinhardtii is modulated by pH.  

PubMed

The effects of pH on metal uptake and toxicity in aquatic organisms are currently poorly understood and remain an evolving topic in studies about the biotic ligand model (BLM). In the present study, the authors investigated how pH may influence long-term (4 d) uranium (U) accumulation and chronic toxicity in batch cultures of the freshwater green alga Chlamydomonas reinhardtii. The toxicity expressed as a function of the free uranyl ion was much greater at pH 7 (effective concentration, 50% [EC50]?=?1.8?×?10(-9) ?M UO2 (2+) ) than at pH 5 (EC50?=?1.2?×?10(-7) ?M UO2 (2+) ). The net accumulation rate of U in algal cells was much higher at pH 7 than at pH 5 for the same free [UO2 (2+) ], but the cells exposed at pH 5 were also more sensitive to intracellular U than the cells at pH 7 with EC50s of 4.0?×?10(-15) and 7.1?×?10(-13) ?mol of internalized U cell(-1) , respectively. The higher cellular sensitivity to U at pH 5 than at pH 7 could be explained partly by the increase in cytosolic U binding to algal soluble proteins or enzymes at pH 5 as observed by subcellular fractionation. To predict U accumulation and toxicity in algae accurately, the important modulating effects of pH on U accumulation and U cellular sensitivity should be considered in the BLM. Environ Toxicol Chem 2014;33:1372-1379. © 2014 SETAC. PMID:24596137

Lavoie, Michel; Sabatier, Sébastien; Garnier-Laplace, Jacqueline; Fortin, Claude

2014-06-01

233

Anaerobic and Aerobic Hydrogen Gas Formation by the Blue-Green Alga Anabaena cylindrica  

PubMed Central

An investigation was made of certain factors involved in the formation of hydrogen gas, both in an anaerobic environment (argon) and in air, by the blue-green alga Anabaena cylindrica. The alga had not been previously adapted under hydrogen gas and hence the hydrogen evolution occurred entirely within the nitrogen-fixing heterocyst cells; organisms grown in a fixed nitrogen source, and which were therefore devoid of heterocysts, did not produce hydrogen under these conditions. Use of the inhibitor dichlorophenyl-dimethyl urea showed that hydrogen formation was directly dependent on photosystem I and only indirectly dependent on photosystem II, consistent with heterocysts being the site of hydrogen formation. The uncouplers carbonyl cyanide chlorophenyl hydrazone and dinitrophenol almost completely inhibited hydrogen formation, indicating that the process occurs almost entirely via the adenosine 5?-triphosphate-dependent nitrogenase. Salicylaldoxime also inhibited hydrogen formation, again illustrating the necessity of photophosphorylation. Whereas hydrogen formation could usually only be observed in anaerobic, dinitrogen-free environments, incubation in the presence of the dinitrogen-fixing inhibitor carbon monoxide plus the hydrogenase inhibitor acetylene resulted in significant formation of hydrogen even in air. Hydrogen formation was studied in batch cultures as a function of age of the cultures and also as a function of culture concentration, in both cases the cultures being harvested in logarithmic growth. Hydrogen evolution (and acetylene-reducing activity) exhibited a distinct maximum with respect to the age of the cultures. Finally, the levels of the protective enzyme, superoxide dismutase, were measured in heterocyst and vegetative cell fractions of the organism; the level was twice as high in heterocyst cells (2.3 units/mg of protein) as in vegetative cells (1.1 units/mg of protein). A simple procedure for isolating heterocyst cells is described.

Daday, Arlene; Platz, Rosalea A.; Smith, Geoffrey D.

1977-01-01

234

Effect of scenedesmus acuminatus green algae extracts on the development of Candida lipolytic yeast in gas condensate-containing media  

NASA Technical Reports Server (NTRS)

Data are given of a comparative study of the growth and development as well as the characteristics of the biomass of the C. Lipolytica yeast according to the content of raw protein, protein, lipids, vitamins in the B group, and residual hydrocarbons during growth in media with de-aromatized gas-condensate FNZ as the carbon source with aqueous and alcohol extracts of S. acuminatus as the biostimulants. It is shown that the decoction and aqueous extract of green algae has the most intensive stimulating effect on the yeast growth. When a decoction of algae is added to the medium, the content of residual hydrocarbons in the biomass of C. lipolytica yeast is reduced by 4%; the quantity of protein, lipids, thamine and inositol with replacement of the yeast autolysate by the decoction of algae is altered little.

Bilmes, B. I.; Kasymova, G. A.; Runov, V. I.; Karavayeva, N. N.

1980-01-01

235

Reclaimed Water and Secondary Wastewater as Alternative Growing Media for Green Algae for Biofuel Production  

Microsoft Academic Search

The microalga Botryococcus braunii is one of many photosynthtic algae species being investigated as renewable feedstocks for production of biofuels. One key advantage of algae as biofuel feedstock, in view of the growing scarcity of fresh water worldwide, is the potential of algae to grow in low-quality water, including in the nutrient-containing effluents from wastewater-treatment plants. Indeed, algae could also

Sara S. Kuwahara; Joel L. Cuello

236

Purification and spectroscopic characterization of a recombinant chloroplastic hemoglobin from the green unicellular alga Chlamydomonas eugametos.  

PubMed

Hemoglobins (Hb), which have the important task of delivering molecular oxygen by facilitating its reversible binding to the heme, are now thought to have evolved in all groups of organisms including prokaryotes, fungi, plants and animals. Our recent finding of a light-inducible chloroplastic Hb in the green unicellular alga Chlamydomonas eugametos has further extend this idea, while raising questions about the function that an Hb could play in a high oxygen environment such as in the chloroplast. In order to understand the role played by this new Hb, we have undertaken its biochemical characterization. To facilitate the characterization of Chlamydomonas Hb, which represents less than 0.01% of the soluble protein in the green alga, the protein has been expressed in Escherichia coli and purified to apparent homogeneity. The purified recombinant protein possesses a non-covalently bound iron-protoporphyrin IX heme. The oxy form of the recombinant Hb. purified directly from bacterial cells, is very stable, with a measured half-life of 7 days at pH 8 and has an ultraviolet/visible spectrum similar to those of the related cytoplasmic Hbs of the ciliated protozoa Paramecium and Tetrahymena and of the cyanobacterium Nostoc commune. In contrast to what has been reported for oxymyoglobins and oxyhemoglobins, the dioxygen molecule bound to the L1637 Hb can be reduced by the electron-transfer mediator phenazine methosulfate in the presence of NADPH, indicating that the heme pocket of Chlamydomonas Hb may be more accessible to small molecules. With regard to this we found that when the small reducing agent sodium dithionite is used to reduce the met form, it must be removed anaerobically from the Hb prior to oxygenation of the protein to stably produce the oxy form. Otherwise, the oxy form is obtained readily from the met form under an oxygenic atmosphere when ferredoxin and ferredoxin NADP+ reductase are used to enzymically reduce the Hb. Finally, the spectra of the deoxy and met forms were unusual, the heme being partly low-spin at physiological pH. These results confirm the existence of a reversible oxygen-binding protein in the chloroplast of C. eugametos. The unusual spectral and biochemical properties of the protein may reflect a specialized function for this Hb. PMID:9022709

Couture, M; Guertin, M

1996-12-15

237

[Peculiarities of growth of the monocellular green algae culture after the influence of electromagnetic field in deuterated water-containing media].  

PubMed

Exposing the inoculum of monocellular green algae Dunalialla tertiolecta and Tetraselmis viridis to 50 Hz electromagnetic field for several hours resulted in a reduced growth rate in both cultures. It was ascertained that heavy water inhibited growth of algae Dunaliella tertiolecta. The light water activated growth of the culture in the exponential phase only. PMID:23650857

Semenov, K T; Aslanian, R R

2013-01-01

238

Nitrogen fixation (acetylene reduction) associated with communities of heterocystous and non-heterocystous blue-green algae in mangrove forests of Sinai  

Microsoft Academic Search

High rates of nitrogen fixation (acetylene reduction) are associated with communities of heterocystous and non-heterocystous blue-green algae, which are widespread and abundant in the coastal mangrove forests of the Sinai Peninsula.

M. Potts; Heinz Steinitz

1979-01-01

239

Culture observation and molecular phylogenetic analysis on the blooming green alga Chaetomorpha valida (Cladophorales, Chlorophyta) from China  

NASA Astrophysics Data System (ADS)

The marine green alga Chaetomorpha valida fouls aquaculture ponds along the coastal cities of Dalian and Rongcheng, China. Unialgal cultures were observed under a microscope to determine the developmental morphological characters of C. valida. Results reveal that gametophytic filaments often produce lateral branches under laboratory culture conditions, suggesting an atypical heteromorphic life cycle of C. valida between unbranched sporophytes and branched gametophytes, which differs from typical isomorphic alternation of Chaetomorpha species. The shape of the basal attachment cell, an important taxonomic character within the genus, was found variable depending on environmental conditions. The 18S rDNA and 28S rDNA regions were used to explore the phylogenetic affinity of the taxa. Inferred trees from 18S rDNA sequences revealed a close relationship between C. valida and Chaetomorpha moniligera. These results would enrich information in general biology and morphological plasticity of C. valida and provided a basis for future identification of green tide forming algae.

Deng, Yunyan; Tang, Xiaorong; Zhan, Zifeng; Teng, Linhong; Ding, Lanping; Huang, Bingxin

2013-05-01

240

Response of the green alga Oophila sp., a salamander endosymbiont, to a PSII-inhibitor under laboratory conditions.  

PubMed

In a rare example of autotroph-vertebrate endosymbiosis, eggs of the yellow-spotted salamander (Ambystoma maculatum) are colonized by a green alga (Oophila sp.) that significantly enhances salamander development. Previous studies have demonstrated the potential for impacts to the salamander embryo when growth of the algae is impaired by exposure to herbicides. To further investigate this relationship, the authors characterized the response of the symbiotic algae (Oophila sp.) alone to the photosystem II (PSII) inhibitor atrazine under controlled laboratory conditions. After extraction of the alga from A. maculatum eggs and optimization of culturing conditions, 4 toxicity assays (96?h each) were conducted. Recovery of the algal population was also assessed after a further 96?h in untreated media. Average median effective concentration (EC50) values of 123?µg?L(-1) (PSII yield), 169?µg?L(-1) (optical density), and 299?µg?L(-1) (growth rate) were obtained after the 96-h exposure. Full recovery of exposed algal populations after 96?h in untreated media was observed for all endpoints, except for optical density at the greatest concentration tested (300?µg?L(-1) ). Our results show that, under laboratory conditions, Oophila sp. is generally less sensitive to atrazine than standard test species. Although conditions of growth in standard toxicity tests are not identical to those in the natural environment, these results provide an understanding of the tolerance of this alga to PSII inhibitors as compared with other species. Environ Toxicol Chem 2014;33:1858-1864. © 2014 SETAC. PMID:24782078

Baxter, Leilan; Brain, Richard; Rodriguez-Gil, Jose Luis; Hosmer, Alan; Solomon, Keith; Hanson, Mark

2014-08-01

241

Influence of extracellular polysaccharides (EPS) produced by two different green unicellular algae on membrane filtration in an algae-based biofuel production process.  

PubMed

In the present study, two strains of green algae named S1 and S2, categorized as the same species of Pseudo-coccomyxa ellipsoidea but showing 99% homology, were cultivated under the same conditions and filtrated with a microfiltration membrane. On the basis of the results of the extracellular polysaccharides (EPS) characteristics of these two green algae and the degree of fouling, the influence of these characteristics on the performance of membrane filtration was investigated. There was no difference in the specific growth rate between the S1 and S2 strains; however, large differences were seen in the amount and quality of EPS between S1 and S2. When the S1 and S2 strains were filtered with a membrane, the trend in the increase in transmembrane pressure (TMP) was quite different. The filtration of the S1 strain showed a rapid increase in TMP, whereas the TMP of the filtration of the S2 strain did not increase at all during the operation. This clearly demonstrated that the characteristics of each strain affect the development of membrane fouling. On the basis of the detailed characterization of solved-EPS (s-EPS) and bound-EPS (b-EPS), it was clarified that s-EPS mainly contributed to irreversible fouling for both operations and the biopolymer-like organic matter contained in b-EPS mainly contributed to reversible fouling. PMID:24804668

Matsumoto, Takaki; Yamamura, Hiroshi; Hayakawa, Jyunpei; Watanabe, Yoshimasa; Harayama, Shigeaki

2014-01-01

242

A cDNA coding for glutathione S-transferase from the unicellular green algae coccomyxa sp  

Microsoft Academic Search

A cDNA coding for glutathione S-transferase (GST) was cloned and sequenced from the unicellular green algae Coccomyxa sp. The predicted 215 amino acid polypeptide (23.9 kDa, pI 5.3) is most similar to the F-type GSTs found in a variety of different eukaryotic organisms. Within this sub-class, the Coccomyxa GST is 42% identical (63% similar) to the flatfish Pleuronectes platessa homologue,

Thomas Hiltonen; Adrian K. Clarke; Jan Karlsson; Göran Samuelsson

1996-01-01

243

Silver nanoparticles toxicity effect on photosystem II photochemistry of the green alga Chlamydomonas reinhardtii treated in light and dark conditions  

Microsoft Academic Search

The inhibitory effect of silver nanoparticles (AgNPs) on photochemical reactions of photosynthesis was investigated using the green alga model Chlamydomonas reinhardtii. Algal cells were exposed to 1, 5, and 10?µmol?L of AgNPs under both light and dark conditions during 6?h. The rapid rise of chlorophyll a fluorescence and the fluorescence imaging system were employed to investigate the alteration of photosystem

David Dewez; Abdallah Oukarroum

2012-01-01

244

Antioxidant properties of a novel phycocyanin extract from the blue-green alga Aphanizomenon flos-aquae  

Microsoft Academic Search

Aphanizomenon flos-aquae (AFA) is a fresh water unicellular blue-green alga (cyanophyta) rich in phycocyanin (PC), a photosynthetic pigment with antioxidant and anti-inflammatory properties.The purpose of this study was to evaluate the ability of a novel natural extract from AFA enriched with PC to protect normal human erythrocytes and plasma samples against oxidative damage in vitro. In red blood cells, oxidative

Serena Benedetti; Francesca Benvenuti; Silvia Pagliarani; Sonia Francogli; Stefano Scoglio; Franco Canestrari

2004-01-01

245

SUSTAINED PHOTOBIOLOGICAL HYDROGEN GAS PRODUCTION UPON REVERSIBLE INACTIVATION OF OXYGEN EVOLUTION IN THE GREEN ALGA Chlamydomonas reinhardtii  

Microsoft Academic Search

The work describes a novel approach for sustained photobiological production of H 2 gas via the reversible hydrogenase pathway in the green alga Chlamydomonas reinhardtii. This single- organism, two-stage H2 production method circumvents the severe O2-sensitivity of the reversible hydrogenase by temporally separating photosynthetic O2 evolution and carbon accumulation from H2 production in the culture. Following application of a stress

Anastasios Melis; Liping Zhang; Marc Forestier; Maria L. Ghirardi; Michael Seibert

1999-01-01

246

The complete nucleotide sequence of a 16S ribosomal RNA gene from a blue-green alga, Anacystis nidulans  

Microsoft Academic Search

The complete nucleotide sequence of a 16S ribosomal RNA gene from a blue-green alga, Anacystis nidulans, has been determined. Its coding region is estimated to be 1,487 base pairs long, which is nearly identical to those reported for chloroplast 16 S rRNA genes and is about 4% shorter than that of the Escherichia coli gene. The 16S rRNA sequence of

Noboru Tomioka; Masahiro Sugiura

1983-01-01

247

Nitrogen-fixation associated with the marine blue-green alga, Trichodesmium , as measured by the acetylene-reduction technique  

Microsoft Academic Search

The marine blue-green alga, Trichodesmium, was collected from the Gulf Stream, near Miami, and occurred in two distinct colonial forms both of which reduced acetylene to ethylene. Trichodesmium was more abundant during the summer but its acetylene-reducing potential showed no obvious seasonal variation. Illuminated Trichodesmium reduced acetylene to ethylene equally well either anaerobically or aerobically (20% oxygen). Acetylene-reduction in the

Barrie F. Taylor; Chun C. Lee; John S. Bunt

1973-01-01

248

Photosynthetic characteristics of planktonic blue-green algae: The response of twenty strains grown under high and low light  

Microsoft Academic Search

The relationship between photosynthetic rate and irradiance was measured for 20 strains of blue-green algae from the genera Anabaena, Aphanizomenon and Oscillatoria. Cells were grown at 20°C under 6:18 light-dark at 30 or 150 µE m s. Under high light the mean light saturated rate of photosynthesis (Pmax) of the Oscillatoria cultures was 14·8 mg O2 mg Chl a h,

R. H. Foy; C. E. Gibson

1982-01-01

249

The abundance of heterocystous blue-green algae in rice soils and inocula used for application in rice fields  

Microsoft Academic Search

Algal populations were quantified (as colony-forming units [CFU] per square centimetre) in 102 samples of rice soils from the Philippines, India, Malaysia and Portugal, and in 22 samples of soil-based inocula from four countries. Heterocystous blue-green algae (BGA) were present in all samples. Nostoc was the dominant genus in most samples, followed by Anabaena and Calothrix. In soils, heterocystous BGA

P. A. Roger; S. Santiago-Ardales; P. M. Reddy; I. Watanabe

1987-01-01

250

Culture of the astaxanthin-producing green alga Haematococcus pluvialis 1. Effects of nutrients on growth and cell type  

Microsoft Academic Search

The freshwater green algaHaematococcus pluvialis (Strain Vischer 1923\\/2) grows best at high nitrate concentrations (about 0.5 to 1.0 g 1?1 KNO3), intermediate phosphate concentration (about 0.1 g 1?1 K2HPO4) and over a wide range of Fe concentrations. Low nitrate or high phosphate induce the formation of reddish palmella cells\\u000a and aplanospores. Mixotrophic growth with acetate improves growth rate and final

Michael A. Borowitzka; John M. Huisman; Ann Osborn

1991-01-01

251

Fast noninvasive activation and inhibition of neural and network activity by vertebrate rhodopsin and green algae channelrhodopsin  

Microsoft Academic Search

Techniques for fast noninvasive control of neuronal excitability will be of major importance for analyzing and understanding neuronal networks and animal behavior. To develop these tools we demonstrated that two light-activated signaling proteins, vertebrate rat rhodopsin 4 (RO4) and the green algae channelrhodospin 2 (ChR2), could be used to control neuronal excitability and modulate synaptic transmission. Vertebrate rhodopsin couples to

Xiang Li; Davina V. Gutierrez; M. Gartz Hanson; Jing Han; Melanie D. Mark; Hillel Chiel; Peter Hegemann; Lynn T. Landmesser; Stefan Herlitze

2005-01-01

252

Photosystem II Reaction Center Damage and Repair in Dunaliella salina (Green Alga)' Analysis under Physiological and Irradiance-Stress Conditions  

Microsoft Academic Search

Mechanistic aspects of the photosystem II (PSII) damage and repair cycle in chloroplasts were investigated. The D1\\/32-kD re- action center protein of PSll (known as the psbA chloroplast gene product) undergoes a frequent light-dependent damage and turn- over in the thylakoid membrane. In the model organism Dunaliella salina (green alga), growth under a limiting intensity of illumination (100 pmol of

Jeong Hee Kim; Jeff A. Nemson; Anastasios Melis

253

Growth of filamentous blue-green algae at high temperatures: a source of biomass for renewable fuels  

Microsoft Academic Search

The growth of filamentous blue-green algae (FBGA) at high temperatures in outdoor, shallow solar ponds is being investigated. The temperature of the 60-m² ponds can be controlled to an average temperature of 45°C. The growth of FBGA at high temperatures offers an opportunity, not presently available from outdoor algal ponds or energy farms, to obtain large amounts of biomass. Growth

H. Timourian; R. L. Ward; T. W. Jeffries

1977-01-01

254

Isolation of a novel oil globule protein from the green alga Haematococcus pluvialis (Chlorophyceae).  

PubMed

Cytoplasmic oil globules of Haematococcus pluvialis (Chlorophyceae) were isolated and analyzed for pigments, lipids and proteins. Astaxanthin appeared to be the only pigment deposited in the globules. Triacyglycerols were the main lipids (more than 90% of total fatty acids) in both the cell-free extract and in the oil globules. Lipid profile analysis of the oil globules showed that relative to the cell-free extract, they were enriched with extraplastidial lipids. A fatty acids profile revealed that the major fatty acids in the isolated globules were oleic acid (18:1) and linoleic acid (18:2). Protein extracts from the globules revealed seven enriched protein bands, all of which were possible globule-associated proteins. A major 33-kDa globule protein was partially sequenced by MS/MS analysis, and degenerate DNA primers were prepared and utilized to clone its encoding gene from cDNA extracted from cells grown in a nitrogen depleted medium under high light. The sequence of this 275-amino acid protein, termed the Haematococcus Oil Globule Protein (HOGP), revealed partial homology with a Chlamydomonas reinhardtii oil globule protein and with undefined proteins from other green algae. The HOGP transcript was barely detectable in vegetative cells, but its level increased by more than 100 fold within 12 h of exposure to nitrogen depletion/high light conditions, which induced oil accumulation. HOGP is the first oil-globule-associated protein to be identified in H. pluvialis, and it is a member of a novel gene family that may be unique to green microalgae. PMID:21732215

Peled, Ehud; Leu, Stefan; Zarka, Aliza; Weiss, Meira; Pick, Uri; Khozin-Goldberg, Inna; Boussiba, Sammy

2011-09-01

255

High Yields of Hydrogen Production Induced by Meta-Substituted Dichlorophenols Biodegradation from the Green Alga Scenedesmus obliquus  

PubMed Central

Hydrogen is a highly promising energy source with important social and economic implications. The ability of green algae to produce photosynthetic hydrogen under anaerobic conditions has been known for years. However, until today the yield of production has been very low, limiting an industrial scale use. In the present paper, 73 years after the first report on H2-production from green algae, we present a combinational biological system where the biodegradation procedure of one meta-substituted dichlorophenol (m-dcp) is the key element for maintaining continuous and high rate H2-production (>100 times higher than previously reported) in chloroplasts and mitochondria of the green alga Scenedesmus obliquus. In particular, we report that reduced m-dcps (biodegradation intermediates) mimic endogenous electron and proton carriers in chloroplasts and mitochondria, inhibit Photosystem II (PSII) activity (and therefore O2 production) and enhance Photosystem I (PSI) and hydrogenase activity. In addition, we show that there are some indications for hydrogen production from sources other than chloroplasts in Scenedesmus obliquus. The regulation of these multistage and highly evolved redox pathways leads to high yields of hydrogen production and paves the way for an efficient application to industrial scale use, utilizing simple energy sources and one meta-substituted dichlorophenol as regulating elements.

Papazi, Aikaterini; Andronis, Efthimios; Ioannidis, Nikolaos E.; Chaniotakis, Nikolaos; Kotzabasis, Kiriakos

2012-01-01

256

High yields of hydrogen production induced by meta-substituted dichlorophenols biodegradation from the green alga Scenedesmus obliquus.  

PubMed

Hydrogen is a highly promising energy source with important social and economic implications. The ability of green algae to produce photosynthetic hydrogen under anaerobic conditions has been known for years. However, until today the yield of production has been very low, limiting an industrial scale use. In the present paper, 73 years after the first report on H(2)-production from green algae, we present a combinational biological system where the biodegradation procedure of one meta-substituted dichlorophenol (m-dcp) is the key element for maintaining continuous and high rate H(2)-production (>100 times higher than previously reported) in chloroplasts and mitochondria of the green alga Scenedesmus obliquus. In particular, we report that reduced m-dcps (biodegradation intermediates) mimic endogenous electron and proton carriers in chloroplasts and mitochondria, inhibit Photosystem II (PSII) activity (and therefore O(2) production) and enhance Photosystem I (PSI) and hydrogenase activity. In addition, we show that there are some indications for hydrogen production from sources other than chloroplasts in Scenedesmus obliquus. The regulation of these multistage and highly evolved redox pathways leads to high yields of hydrogen production and paves the way for an efficient application to industrial scale use, utilizing simple energy sources and one meta-substituted dichlorophenol as regulating elements. PMID:23145057

Papazi, Aikaterini; Andronis, Efthimios; Ioannidis, Nikolaos E; Chaniotakis, Nikolaos; Kotzabasis, Kiriakos

2012-01-01

257

THE EFFECTS OF ISOPROPYL N-PHENYL CARBAMATE ON THE GREEN ALGA OEDOGONIUM CARDIACUM  

PubMed Central

Cell division in vegetative filaments of the green alga Oedogonium cardiacum is presented as an experimental system. We report on how we have used this system to study the effects of isopropyl N-phenylcarbamate (IPC) on the mitotic apparatus and on the phycoplast, a planar array of cytokinetic microtubules. Polymerization of microtubules was prevented when filaments, synchronized by a light/dark regime and chilled (2°C) while in metaphase or just before phycoplast formation, were exposed to 5.5 x 10-4 M IPC and then returned to room temperature. Spindles reformed or phycoplasts formed when these filaments were transferred to growth medium free of IPC. However, the orientation of both microtubular systems was disturbed: the mitotic apparatus often contained three poles, frequently forming three daughter nuclei upon karyokinesis; the phycoplast was often stellate rather than planar, and it sometimes was displaced to the side of both daughter nuclei, resulting in a binucleate and an anucleate cell upon cytokinesis. Our results suggest that IPC (a) prevents the assembly of microtubules, (b) increases the number of functional polar bodies, and (c) affects the orientation of microtubules in O. cardiacum. High voltage (1,000 kV) electron microscopy of 0.5-µm thick sections allowed us to visualize the polar structures, which were not discernible in thin sections.

Coss, Ronald A.; Pickett-Heaps, Jeremy D.

1974-01-01

258

Active Hydrocarbon Biosynthesis and Accumulation in a Green Alga, Botryococcus braunii (Race A)  

PubMed Central

Among oleaginous microalgae, the colonial green alga Botryococcus braunii accumulates especially large quantities of hydrocarbons. This accumulation may be achieved more by storage of lipids in the extracellular space rather than in the cytoplasm, as is the case for all other examined oleaginous microalgae. The stage of hydrocarbon synthesis during the cell cycle was determined by autoradiography. The cell cycle of B. braunii race A was synchronized by aminouracil treatment, and cells were taken at various stages in the cell cycle and cultured in a medium containing [14C]acetate. Incorporation of 14C into hydrocarbons was detected. The highest labeling occurred just after septum formation, when it was about 2.6 times the rate during interphase. Fluorescent and electron microscopy revealed that new lipid accumulation on the cell surface occurred during at least two different growth stages and sites of cells. Lipid bodies in the cytoplasm were not prominent in interphase cells. These lipid bodies then increased in number, size, and inclusions, reaching maximum values just before the first lipid accumulation on the cell surface at the cell apex. Most of them disappeared from the cytoplasm concomitant with the second new accumulation at the basolateral region, where extracellular lipids continuously accumulated. The rough endoplasmic reticulum near the plasma membrane is prominent in B. braunii, and the endoplasmic reticulum was often in contact with both a chloroplast and lipid bodies in cells with increasing numbers of lipid bodies. We discuss the transport pathway of precursors of extracellular hydrocarbons in race A.

Hirose, Mana; Mukaida, Fukiko; Okada, Sigeru

2013-01-01

259

Photosynthetic regeneration of ATP using a strain of thermophilic blue-green algae  

SciTech Connect

Photosynthetic ATP accumulation was shown in the presence of exogenous ADP plus ortho-phosphate on illumination to the intact cells of a strain of thermophilic blue-green algae isolated from Matsue hot springs, Mastigocladus sp. Kinetic studies of various effectors on the ATP accumulation proved that the ATP synthesis depends mainly on the cyclic photophosphorylation system around photosystem I (PS-I) in the algal cells. The temperature and pH optima for the accumulation were found at 45 degrees C and pH 7.5. Maximum yield was obtained with light intensity higher than 15 mW/squared cm. Borate ion exerted pronounced enhancement on the ATP synthesis. With a continuous reactor at a flow rate of 1 ml/hour at 45 degrees C and pH 7.5, efficient photoconversion of ADP (2mM, at substrate reservoir) to ATP (1mM, at product outlet) has been maintained for a period of 2.5 days, though the efficiency has decreased in a further 2-day period to the level of 0.5 mM ATP/9.5 h of residence time. (Refs. 24).

Sawa, Y.; Kanayama, K.; Ochiai, H.

1982-02-01

260

Growth rate affects the responses of the green alga Tetraselmis suecica to external perturbations.  

PubMed

Acclimation to environmental changes involves a modification of the expressed proteome and metabolome. The reproductive advantage associated with the higher fitness that acclimation provides to the new conditions more than compensates for the costs of acclimation. To exploit such an advantage, however, the duration of the perturbation must be sufficiently long relative to the growth rate. Otherwise, a selective pressure may exist in favour of responses that minimize changes in carbon allocation and resource use and do not require reversal of the acclimation after the perturbation ceases (compositional homeostasis). We hypothesize that the choice between acclimation and homeostasis depends on the duration of the perturbation relative to the length of the cell cycle. To test this hypothesis, we cultured the green alga Tetraselmis suecica at two growth rates and subjected the cultures to three environmental perturbations. Carbon allocation was studied with Fourier transform infrared (FTIR) spectroscopy; elemental stoichiometry was investigated by total reflection X-ray fluorescence (TXRF) spectroscopy. Our data confirmed that growth rate is a crucial factor for C allocation in response to external changes, with a higher degree of compositional homeostasis in cells with lower growth rate. PMID:23927015

Fanesi, Andrea; Raven, John A; Giordano, Mario

2014-02-01

261

5'-monohydroxyphylloquinone is the dominant naphthoquinone of PSI in the green alga Chlamydomonas reinhardtii.  

PubMed

Thylakoid membranes contain two types of quinones, benzoquinone (plastoquinone) and naphthoquinone, which are involved in photosynthetic electron transfer. Unlike the benzoquinone, the chemical species of naphthoquinone present (phylloquinone, menaquinone-4 and 5'-monohydroxyphylloquinone) varies depending on the oxygenic photosynthetic organisms. The green alga Chlamydomonas reinhardtii has been used as a model organism to study the function of the naphthoquinone bound to PSI. However, the level of phylloquinone and the presence of other naphthoquinones in this organism remain unknown. In the present study, we found that 5'-monohydroxyphylloquinone is the predominant naphthoquinone in cell and thylakoid extracts based on the retention time during reverse phase HPLC, absorption and mass spectrometry measurements. It was shown that 5'-monohydroxyphylloquinone is enriched 2.5-fold in the PSI complex as compared with thylakoid membranes but that it is absent from PSI-deficient mutant cells. We also found a small amount of phylloquinone in the cells and in the PSI complex and estimated that accumulated 5'-monohydroxyphylloquinone and phylloquinone account for approximately 90 and 10%, respectively, of the total naphthoquinone content. The ratio of these two naphthoquinones remained nearly constant in the cells and in the PSI complexes from logarithmic and stationary cell growth stages. We conclude that both 5'-monohydroxyphylloquinone and phylloquinone stably co-exist as major and minor naphthoquinones in Chlamydomonas PSI. PMID:22138100

Ozawa, Shin-ichiro; Kosugi, Makiko; Kashino, Yasuhiro; Sugimura, Takashi; Takahashi, Yuichiro

2012-01-01

262

Oxygen-dependent proton efflux in cyanobacteria (blue-green algae). [Anabaena variabilis  

SciTech Connect

The oxygen-dependent proton efflux (in the dark) of intact cells of Anabaena variabilis and four other cyanobacteria (blue-green algae) was investigated. In contrast to bacteria and isolated mitochondria, an H/sup +//e ratio (= protons translocated per electron transported) of only 0.23 to 0.35 and a P/e ratio of 0.8 to 1.5 were observed, indicative of respiratory electron transport being localized essentially on the thylakoids, not on the cytoplasmic membrane. Oxygen-induced acidification of the medium was sensitive to cyanide and the uncoupler carbonyl cyanide m-chlorophenylhydrazone. Inhibitors such as 2,6-dinitrophenol and vanadate exhibited a significant decrease in the H/sup +//e ratio. After the oxygen pulse, electron transport started immediately, but proton efflux lagged 40 to 60 s behind, a period also needed before maximum ATP pool levels were attained. The authors suggest that proton efflux in A. variabilis is due to a proton-translocating ATP hydrolase (ATP-consuming ATPase) rather than to respiratory electron transport located on the cytoplasmic membrane.

Scherer, S.; Stuerzl, E.; Boeger, P.

1984-05-01

263

Respiratory-deficient mutants of the unicellular green alga Chlamydomonas: a review.  

PubMed

Genetic manipulation of the unicellular green alga Chlamydomonas reinhardtii is straightforward. Nuclear genes can be interrupted by insertional mutagenesis or targeted by RNA interference whereas random or site-directed mutagenesis allows the introduction of mutations in the mitochondrial genome. This, combined with a screen that easily allows discriminating respiratory-deficient mutants, makes Chlamydomonas a model system of choice to study mitochondria biology in photosynthetic organisms. Since the first description of Chlamydomonas respiratory-deficient mutants in 1977 by random mutagenesis, many other mutants affected in mitochondrial components have been characterized. These respiratory-deficient mutants increased our knowledge on function and assembly of the respiratory enzyme complexes. More recently some of these mutants allowed the study of mitochondrial gene expression processes poorly understood in Chlamydomonas. In this review, we update the data concerning the respiratory components with a special focus on the assembly factors identified on other organisms. In addition, we make an inventory of different mitochondrial respiratory mutants that are inactivated either on mitochondrial or nuclear genes. PMID:24139906

Salinas, Thalia; Larosa, Véronique; Cardol, Pierre; Maréchal-Drouard, Laurence; Remacle, Claire

2014-05-01

264

Palindromic Genes in the Linear Mitochondrial Genome of the Nonphotosynthetic Green Alga Polytomella magna  

PubMed Central

Organelle DNA is no stranger to palindromic repeats. But never has a mitochondrial or plastid genome been described in which every coding region is part of a distinct palindromic unit. While sequencing the mitochondrial DNA of the nonphotosynthetic green alga Polytomella magna, we uncovered precisely this type of genic arrangement. The P. magna mitochondrial genome is linear and made up entirely of palindromes, each containing 1–7 unique coding regions. Consequently, every gene in the genome is duplicated and in an inverted orientation relative to its partner. And when these palindromic genes are folded into putative stem-loops, their predicted translational start sites are often positioned in the apex of the loop. Gel electrophoresis results support the linear, 28-kb monomeric conformation of the P. magna mitochondrial genome. Analyses of other Polytomella taxa suggest that palindromic mitochondrial genes were present in the ancestor of the Polytomella lineage and lost or retained to various degrees in extant species. The possible origins and consequences of this bizarre genomic architecture are discussed.

Smith, David Roy; Hua, Jimeng; Archibald, John M.; Lee, Robert W.

2013-01-01

265

Simultaneous Measurement of Oxygen and Hydrogen Exchange from the Blue-Green Alga Anabaena1  

PubMed Central

Two Clark-type polarographic electrodes were used to measure simultaneous H2 and O2 exchange from three species of the blue-green alga Anabaena. Maximum H2 photoevolution from N2-fixing cultures of Anabaena required only the removal of dissolved O2 and N2; no adaptation period was necessary. No correlation of H2 photoproduction with photosynthetic O2 evolution, beyond their mutual light requirement, was found. Hydrogen photoevolution has the following characteristics in common with N2 fixation in these organisms: DCMU insensitivity; similar white light dependency with very low dark production rates; maximum efficiency in photosystem I light; inhibition by N2, O2 and acetylene; and an apparent requirement for the presence of heterocysts. Growth on nitrate medium reduces, and on ammonium medium obliterates, both reactions. Cultures grown under limiting CO2 conditions have H2 photoproduction rates proportional to their growth rates. Hydrogenase activity is inferred from H2 uptake in the dark, but this activity apparently is independent of the photoevolution of H2 which is ascribed strictly to the nitrogenase system.

Jones, Larry W.; Bishop, Norman I.

1976-01-01

266

Biosorption of trivalent chromium by free and immobilized blue green algae: kinetics and equilibrium studies.  

PubMed

The process of biosorption of trivalent chromium (Cr(3+)) by live culture of Spirulina platensis and the sorption potential by the dried biomass, in both free and immobilized states have been investigated for a simulated chrome liquor in the concentration range of 100-4500 ppm. Both live and dried biomass were very good biosorbents as they could remove high amounts of chromium from tannery wastewater. Polyurethane foam and sodium alginate were used as immobilizing agents and their performances compared. Biosorption kinetic data on Cr(3+) sorption onto dried biomass were analyzed using pseudo-first-and pseudo-second-order kinetic models in batch column experiments. The second-order equation was more appropriate to predict the rate of biosorption. Subsequently, the effects of height of packing & diameter of the column, concentration of blue-green algae (BGA) in varying amounts of sodium alginate, chromium concentration were studied. The results fit into both Langmuir & Freundlich isotherm models with very high regression coefficients. Furthermore, equilibrium studies using retan chrome liquor (RCL), with a chromium concentration of 1660 ppm, obtained from a tannery also showed promising results. In general, our studies indicate the efficacy of the algal species in removal of chromium from tannery wastewater. PMID:18273745

Shashirekha, V; Sridharan, M R; Swamy, Mahadeswara

2008-03-01

267

Active hydrocarbon biosynthesis and accumulation in a green alga, Botryococcus braunii (race A).  

PubMed

Among oleaginous microalgae, the colonial green alga Botryococcus braunii accumulates especially large quantities of hydrocarbons. This accumulation may be achieved more by storage of lipids in the extracellular space rather than in the cytoplasm, as is the case for all other examined oleaginous microalgae. The stage of hydrocarbon synthesis during the cell cycle was determined by autoradiography. The cell cycle of B. braunii race A was synchronized by aminouracil treatment, and cells were taken at various stages in the cell cycle and cultured in a medium containing [(14)C]acetate. Incorporation of (14)C into hydrocarbons was detected. The highest labeling occurred just after septum formation, when it was about 2.6 times the rate during interphase. Fluorescent and electron microscopy revealed that new lipid accumulation on the cell surface occurred during at least two different growth stages and sites of cells. Lipid bodies in the cytoplasm were not prominent in interphase cells. These lipid bodies then increased in number, size, and inclusions, reaching maximum values just before the first lipid accumulation on the cell surface at the cell apex. Most of them disappeared from the cytoplasm concomitant with the second new accumulation at the basolateral region, where extracellular lipids continuously accumulated. The rough endoplasmic reticulum near the plasma membrane is prominent in B. braunii, and the endoplasmic reticulum was often in contact with both a chloroplast and lipid bodies in cells with increasing numbers of lipid bodies. We discuss the transport pathway of precursors of extracellular hydrocarbons in race A. PMID:23794509

Hirose, Mana; Mukaida, Fukiko; Okada, Sigeru; Noguchi, Tetsuko

2013-08-01

268

New chemical constituents from Oryza sativa straw and their algicidal activities against blue-green algae.  

PubMed

Five new constituents, 5,4'-dihydroxy-7,3'-dimethoxyflavone-4'-O-?-D-xylopyranosyl-(2a?1b)-2a-O-?-D-xylopyranosyl-(2b?1c)-2b-O-?-D-xylopyranosyl-2c-octadecanoate (1), 5,4'-dihydroxy-7,3'-dimethoxyflavone-4'-O-?-D-xylopyranosyl-(2a?1b)-2a-O-?-D-xylopyranosyl-(2b?1c)-2b-O-?-D-xylopyranosyl-(2c?1d)-2c-O-?-D-xylopyranosyl-2d-octadecanoate (2), kaempferol-3-O-?-D-xylopyranosyl-(2a?1b)-2a-O-?-D-xylopyranosyl-(2b?1c)-2b-O-?-D-xylopyranosyl-(2c?1d)-2c-O-?-D-xylopyranosyl-2d-hexadecanoate (3), methyl salicylate-2-O-?-D-xylopyranosyl-(2a?1b)-2a-O-?-D-xylopyranosyl-(2b?1c)-2b-O-?-D-xylopyranosyl-(2c?1d)-2c-O-?-D-xylopyranosyl-(2d?1e)-2d-O-?-D-xylopyranosyl-(2e?1f)-2e-O-?-D-xylopyranosyl-(2f?1g)-2f-O-?-D-xylopyranosyl-(2g?1h)-2g-O-?-D-xylopyranosyl-2h-geranilan-8',10'-dioic acid-1'-oate (4), and oleioyl-?-D-arabinoside (5), along with eight known compounds, were isolated from a methanol extract of Oryza sativa straw. The structures of the new compounds were elucidated using one- and two-dimensional NMR spectroscopies in combination with IR, ESI/MS, and HR-ESI/FTMS. In bioassays with blue-green algae, the efficacies of the algicidal activities of the five new compounds (1-5) were evaluated at concentrations of 1, 10, and 100 mg/L. Compound 5 had the highest growth inhibition (92.6 ± 0.3%) for Microcystis aeruginosa UTEX 2388 at a concentration of 100 ppm (mg/L). Compound 5 has high potential for the ecofriendly control of weeds and algae harmful to water-logged rice. PMID:23889328

Ahmad, Ateeque; Kim, Seung-Hyun; Ali, Mohd; Park, Inmyoung; Kim, Jin-Seog; Kim, Eun-Hye; Lim, Ju-Jin; Kim, Seul-Ki; Chung, Ill-Min

2013-08-28

269

Benthic Algae as Monitors of Heavy Metals in Various Polluted Rivers by Energy Dispersive X-Ray Spectrometer  

Microsoft Academic Search

Benthic microalgae assemblages were used as monitors of copper (Cu), zinc (Zn), and chromium (Cr) in various polluted rivers of San-Yeh-Kong, in southern Taiwan, and analyzed using Scanning Electron Microscope and Energy Dispersive X-Ray Spectrometer (SEM-EDS). Under SEM-EDS, the benthic algae from seriously polluted rivers (dominant by the cyanobacteria Oscillatoria chalybea, green algae Euglena acus and diatom Nitzschia palea under

Sheue-Duan Lai; Pei-Chung Chen; Hoang-Kao Hsu

2003-01-01

270

The salt relations of marine and halophilic species of the unicellular green alga, Dunaliella  

Microsoft Academic Search

1.Comparisons were made of the effects of salt on the exponential growth rates of two unicellular algae,Dunaliella tertiolecta (marine) andDunaliella viridis (halophilic).2.The algae contained glycerol in amounts which varied directly with the salt concentration of the growth media. The highest measured glycerol content ofD. tertiolecta was approximately equivalent to 1.4 molal and occurred in algae grown in 1.36 M sodium

Lesley Joyce Borowitzka; Austin Duncan Brown

1974-01-01

271

Microbial load in mass cultures of green algae Scenedesmus acutus and its processed powder  

Microsoft Academic Search

Microbial contamination in cultures of the alga,Scenedesmus acutus raised in outdoor open tanks and also in the processed powder of the alga was monitored; The total bacterial population increased\\u000a with time during the growth period of six days. When a combination of molasses and carbondioxide was employed as carbon source\\u000a for this alga, the bacterial load increased to 10 colony

M. Mahadevaswamy; L. V. Venkataraman

1981-01-01

272

Marine diatoms in polar and sub-polar environments and their application to Late Pleistocene paleoclimate reconstruction  

NASA Astrophysics Data System (ADS)

Diatoms are one of the major phytoplankton groups in polar and sub-polar marine environments along with green algae and chrysophytes. Diatoms are composed of two components, a two-valve test made of amorphous silica and an organic cell encapsulated into the test. Mucilage covering the test and proteins embedded in the silica lattice of the test completes the organic pool of the diatoms. The preservation of these two components into deep-sea sediments allows for a large set of diatom-based proxies to infer past oceanographic and climatic changes in polar and sub-polar marine environments. Most diatom species in polar and sub-polar marine environments exhibit a narrow range of ecological preferences, especially in terms of sea-surface temperature and sea ice conditions. Preserved diatom assemblages in deep-sea sediments mirror the diatom assemblages in the phytoplankton. It is subsequently possible to extrapolate the relationships between diatom assemblages in surface sediments and modern parameters to down-core fossil assemblages to document past changes in sea-surface temperatures and sea ice conditions. Congruent analysis of biogenic silica and organic carbon and stable isotope ratios (O, Si in the silica matrix and C, N in the diatom-intrinsic organic matter) provides information on siliceous productivity, nutrient cycling and water mass circulation. Measurements of diatom biomarkers give complementary information on sea ice conditions and siliceous productivity.

Crosta, Xavier

2011-05-01

273

Evidence of Coexistence of C3 and C4 Photosynthetic Pathways in a Green-Tide-Forming Alga, Ulva prolifera  

PubMed Central

Ulva prolifera, a typical green-tide-forming alga, can accumulate a large biomass in a relatively short time period, suggesting that photosynthesis in this organism, particularly its carbon fixation pathway, must be very efficient. Green algae are known to generally perform C3 photosynthesis, but recent metabolic labeling and genome sequencing data suggest that they may also perform C4 photosynthesis, so C4 photosynthesis might be more wide-spread than previously anticipated. Both C3 and C4 photosynthesis genes were found in U. prolifera by transcriptome sequencing. We also discovered the key enzymes of C4 metabolism based on functional analysis, such as pyruvate orthophosphate dikinase (PPDK), phosphoenolpyruvate carboxylase (PEPC), and phosphoenolpyruvate carboxykinase (PCK). To investigate whether the alga operates a C4-like pathway, the expression of rbcL and PPDK and their enzyme activities were measured under various forms and intensities of stress (differing levels of salinity, light intensity, and temperature). The expression of rbcL and PPDK and their enzyme activities were higher under adverse circumstances. However, under conditions of desiccation, the expression of rbcL and ribulose-1, 5-biphosphate carboxylase (RuBPCase) activity was lower, whereas that of PPDK was higher. These results suggest that elevated PPDK activity may alter carbon metabolism and lead to a partial operation of C4-type carbon metabolism in U. prolifera, probably contributing to its wide distribution and massive, repeated blooms in the Yellow Sea.

Zhang, Xiaowen; Xu, Dong; Mou, Shanli; Cao, Shaona; Zheng, Zhou; Miao, Jinlai; Ye, Naihao

2012-01-01

274

Structural studies of ?-carbonic anhydrase from the green alga Coccomyxa: inhibitor complexes with anions and acetazolamide.  

PubMed

The ?-class carbonic anhydrases (?-CAs) are widely distributed among lower eukaryotes, prokaryotes, archaea, and plants. Like all CAs, the ?-enzymes catalyze an important physiological reaction, namely the interconversion between carbon dioxide and bicarbonate. In plants the enzyme plays an important role in carbon fixation and metabolism. To further explore the structure-function relationship of ?-CA, we have determined the crystal structures of the photoautotroph unicellular green alga Coccomyxa ?-CA in complex with five different inhibitors: acetazolamide, thiocyanate, azide, iodide, and phosphate ions. The tetrameric Coccomyxa ?-CA structure is similar to other ?-CAs but it has a 15 amino acid extension in the C-terminal end, which stabilizes the tetramer by strengthening the interface. Four of the five inhibitors bind in a manner similar to what is found in complexes with ?-type CAs. Iodide ions, however, make contact to the zinc ion via a zinc-bound water molecule or hydroxide ion--a type of binding mode not previously observed in any CA. Binding of inhibitors to Coccomyxa ?-CA is mediated by side-chain movements of the conserved residue Tyr-88, extending the width of the active site cavity with 1.5-1.8 Ĺ. Structural analysis and comparisons with other ?- and ?-class members suggest a catalytic mechanism in which the movements of Tyr-88 are important for the CO(2)-HCO(3)(-) interconversion, whereas a structurally conserved water molecule that bridges residues Tyr-88 and Gln-38, seems important for proton transfer, linking water molecules from the zinc-bound water to His-92 and buffer molecules. PMID:22162771

Huang, Shenghua; Hainzl, Tobias; Grundström, Christin; Forsman, Cecilia; Samuelsson, Göran; Sauer-Eriksson, A Elisabeth

2011-01-01

275

Structural Studies of ?-Carbonic Anhydrase from the Green Alga Coccomyxa: Inhibitor Complexes with Anions and Acetazolamide  

PubMed Central

The ?-class carbonic anhydrases (?-CAs) are widely distributed among lower eukaryotes, prokaryotes, archaea, and plants. Like all CAs, the ?-enzymes catalyze an important physiological reaction, namely the interconversion between carbon dioxide and bicarbonate. In plants the enzyme plays an important role in carbon fixation and metabolism. To further explore the structure-function relationship of ?-CA, we have determined the crystal structures of the photoautotroph unicellular green alga Coccomyxa ?-CA in complex with five different inhibitors: acetazolamide, thiocyanate, azide, iodide, and phosphate ions. The tetrameric Coccomyxa ?-CA structure is similar to other ?-CAs but it has a 15 amino acid extension in the C-terminal end, which stabilizes the tetramer by strengthening the interface. Four of the five inhibitors bind in a manner similar to what is found in complexes with ?-type CAs. Iodide ions, however, make contact to the zinc ion via a zinc-bound water molecule or hydroxide ion — a type of binding mode not previously observed in any CA. Binding of inhibitors to Coccomyxa ?-CA is mediated by side-chain movements of the conserved residue Tyr-88, extending the width of the active site cavity with 1.5-1.8 Ĺ. Structural analysis and comparisons with other ?- and ?-class members suggest a catalytic mechanism in which the movements of Tyr-88 are important for the CO2-HCO3- interconversion, whereas a structurally conserved water molecule that bridges residues Tyr-88 and Gln-38, seems important for proton transfer, linking water molecules from the zinc-bound water to His-92 and buffer molecules.

Huang, Shenghua; Hainzl, Tobias; Grundstrom, Christin; Forsman, Cecilia; Samuelsson, Goran; Sauer-Eriksson, A. Elisabeth

2011-01-01

276

Optimization of culture conditions and comparison of biomass productivity of three green algae.  

PubMed

Culture conditions for the mass production of three green algae, Chlorella sp., Dunaliella salina DCCBC2 and Dunaliella sp., were optimized using a response surface methodology (RSM). A central composite design was applied to investigate the effects of initial pH, nitrogen and phosphate concentrations on the cultivation of microalgae. The optimal growth conditions estimated from the design are as follows: Chlorella sp. (initial pH 7.2, ammonium 17 mM, phosphate 1.2 mM), D. salina DCCBC2 (initial pH 8.0, nitrate 3.3 mM, phosphate 0.0375 mM) and Dunaliella sp. (initial pH 8.0, nitrate 3.7 mM, phosphate 0.17 mM). Culturing the microalgae with the optimized conditions confirmed that the maximum growth rates were attained for these parameters. The optimum CO(2) concentrations of Chlorella sp., D. salina DCCBC2 and Dunaliella sp. were 1.0, 3.0 and 1.0% (v/v), respectively. The specific growth rates (?) of Chlorella sp., D. salina DCCBC2 and Dunaliella sp. were 0.58, 0.78 and 0.56 day(-1), respectively, and the biomass productivities were 0.28, 0.54 and 0.30 g dry cell wt l(-1) day(-1), respectively. The CO(2) fixation rates of Chlorella sp., D. salina DCCBC2 and Dunaliella sp. were 42.8, 90.9 and 45.5 mg l(-1) day(-1), respectively. Mixotrophic cultivation of Chlorella sp. with glucose increased biomass productivity from 0.28 to 0.51 g dry cell wt l(-1) day(-1). However, D. salina DCCBC2 and Dunaliella sp. were not stimulated by several organic compounds tested. PMID:21909669

Kim, Wonduck; Park, Jang Min; Gim, Geun Ho; Jeong, Sang-Hwa; Kang, Chang Min; Kim, Duk-Jin; Kim, Si Wouk

2012-01-01

277

Response of the Photosynthetic Apparatus in Dunaliella salina (Green Algae) to Irradiance Stress 1  

PubMed Central

The response of the photosynthetic apparatus in the green alga Dunaliella salina, to irradiance stress was investigated. Cells were grown under physiological conditions at 500 millimoles per square meter per second (control) and under irradiance-stress conditions at 1700 millimoles per square meter per second incident intensity (high light, HL). In control cells, the light-harvesting antenna of photosystem I (PSI) contained 210 chlorophyll a/b molecules. It was reduced to 105 chlorophyll a/b in HL-grown cells. In control cells, the dominant form of photosystem II (PSII) was PSII?(about 63% of the total PSII) containing >250 chlorophyll a/b molecules. The smaller antenna size PSII? centers (about 37% of PSII) contained 135 ± 10 chlorophyll a/b molecules. In sharp contrast, the dominant form of PSII in HL-grown cells accounted for about 95% of all PSII centers and had an antenna size of only about 60 chlorophyll a molecules. This newly identified PSII unit is termed PSII?. The HL-grown cells showed a substantially elevated PSII/PSI stoichiometry ratio in their thylakoid membranes (PSII/PSI = 3.0/1.0) compared to that of control cells (PSII/PSI = 1.4/1.0). The steady state irradiance stress created a chronic photoinhibition condition in which D. salina thylakoids accumulate an excess of photochemically inactive PSII units. These PSII units contain both the reaction center proteins and the core chlorophyll-protein antenna complex but cannot perform a photochemical charge separation. The results are discussed in terms of regulatory mechanism(s) in the plant cell whose function is to alleviate the adverse effect of irradiance stress. Images Figure 4 Figure 5 Figure 6 Figure 7

Smith, Barbara M.; Morrissey, Peter J.; Guenther, Jeanne E.; Nemson, Jeff A.; Harrison, Michael A.; Allen, John F.; Melis, Anastasios

1990-01-01

278

Nuclear genes encoding chloroplast hemoglobins in the unicellular green alga Chlamydomonas eugametos.  

PubMed

When the green unicellular alga Chlamydomonas eugametos is grown under light/dark regimes, nuclear genes are periodically activated in response to the changes in light conditions. These genetic responses are dependent upon the activation of genes associated with photosynthesis (LI616 and LI637), nonphotosynthetic photoreceptors (LI410 and LI818) and the biological clock (LI818). We report here that the LI410 and LI637 genes are part of a small gene family encoding hemoglobins (Hbs) related to those from two unicellular eukaryotes, the ciliated protozoa Paramecium caudatum and Tetrahymena pyriformis, and from the cyanobacterium Nostoc commune. Investigations of the intracellular localization of C. eugametos Hbs by means of immunogold electron microscopy indicate that these proteins are predominantly located in the chloroplast, particularly in the pyrenoid and the thylakoid region. To our knowledge, this constitutes the first evidence for the presence of Hbs in chloroplasts. Alignment of the LI637 cDNA nucleotide sequence with its corresponding genomic sequence indicates that the LI637 gene contains three introns, the positions of which are compared with those in the Hb genes of plants, animals and the ciliate P. caudatum. Although the LI637 gene possesses a three-intron/four-exon pattern similar to that of plant leghemoglobin genes, introns are inserted at different positions. Similarly the position of the single intron in the P. caudatum gene differs from the intron sites in the LI637 gene. The latter observations argue against the current view that all eukaryotic Hbs have evolved from a common ancestor having a gene structure identical to that of plant or animal Hbs. PMID:8177215

Couture, M; Chamberland, H; St-Pierre, B; Lafontaine, J; Guertin, M

1994-04-01

279

Colony Organization in the Green Alga Botryococcus braunii is Specified by a Complex Extracellular Matrix  

SciTech Connect

Botryococcus braunii is a colonial green alga whose cells associate via a complex extracellular matrix (ECM) and produce prodigious amounts of liquid hydrocarbons that can be readily converted into conventional combustion engine fuels. We used quickfreeze deep-etch electron microscopy and biochemical/histochemical analysis to elucidate many new features of B. braunii cell/ colony organization and composition. Intracellular lipid bodies associate with the chloroplast and endoplasmic reticulum (ER) but show no evidence of being secreted. The ER displays striking fenestrations and forms a continuous subcortical system in direct contact with the cell membrane. The ECM has three distinct components. (i) Each cell is surrounded by a fibrous ?-1, 4- and/or ?-1, 3-glucan-containing cell wall. (ii) The intracolonial ECM space is filled with a cross-linked hydrocarbon network permeated with liquid hydrocarbons. (iii) Colonies are enclosed in a retaining wall festooned with a fibrillar sheath dominated by arabinose-galactose polysaccharides, which sequesters ECM liquid hydrocarbons. Each cell apex associates with the retaining wall and contributes to its synthesis. Retaining-wall domains also form "drapes" between cells, with some folding in on themselves and penetrating the hydrocarbon interior of a mother colony, partitioning it into daughter colonies. We propose that retaining- wall components are synthesized in the apical Golgi apparatus, delivered to apical ER fenestrations, and assembled on the surfaces of apical cell walls, where a proteinaceous granular layer apparently participates in fibril morphogenesis. We further propose that hydrocarbons are produced by the nonapical ER, directly delivered to the contiguous cell membrane, and pass across the nonapical cell wall into the hydrocarbon-based ECM.

Weiss, Taylor [Texas A& M University; Roth, Robyn [Washington University of St. Louis; Goodson, Carrie [Washington University of St. Louis; Vithda, Stanislav [Texas A& M University; Black, Ian [University of Georgia; Azadi, Parastoo [University of Georgia; Rusch, Jannette [Washington University of St. Louis; Holzenburg, Andreas [Texas A& M University; Devarenne, Timothy [Texas A& M University; Goodenough, Ursula [Washington University of St. Louis

2012-01-01

280

Artificial microfossils - Experimental studies of permineralization of blue-green algae in silica.  

NASA Technical Reports Server (NTRS)

A technique has been developed to artificially fossilize microscopic algae in crystalline silica under conditions of moderately elevated temperature and pressure. The technique is designed to simulate geochemical processes thought to have resulted in the preservation of organic microfossils in Precambrian bedded cherts. In degree of preservation and mineralogic setting, the artificially permineralized microorganisms are comparable to naturally occurring fossil algae.

Oehler, J. H.; Schopf, J. W.

1971-01-01

281

Variability and abundance of the epiphytic bacterial community associated with a green marine Ulvacean alga  

Microsoft Academic Search

Marine Ulvacean algae are colonized by dense microbial communities predicted to have an important role in the development, defense and metabolic activities of the plant. Here we assess the diversity and seasonal dynamics of the bacterial community of the model alga Ulva australis to identify key groups within this epiphytic community. A total of 48 algal samples of U. australis

Niina A Tujula; Gregory R Crocetti; Catherine Burke; Torsten Thomas; Carola Holmström; Staffan Kjelleberg

2010-01-01

282

Complete sequence of the mitochondrial DNA of the red alga Porphyra purpurea. Cyanobacterial introns and shared ancestry of red and green algae.  

PubMed Central

The mitochondrial DNA (mtDNA) of Porphyra purpurea, a circular-mapping genome of 36,753 bp, has been completely sequenced. A total of 57 densely packed genes has been identified, including the basic set typically found in animals and fungi, as well as seven genes characteristic of protist and plant mtDNAs and specifying ribosomal proteins and subunits of succinate:ubiquinone oxidoreductase. The mitochondrial large subunit rRNA gene contains two group II introns that are extraordinarily similar to those found in the cyanobacterium Calothrix sp, suggesting a recent lateral intron transfer between a bacterial and a mitochondrial genome. Notable features of P. purpurea mtDNA include the presence of two 291-bp inverted repeats that likely mediate homologous recombination, resulting in genome rearrangement, and of numerous sequence polymorphisms in the coding and intergenic regions. Comparative analysis of red algal mitochondrial genomes from five different, evolutionarily distant orders reveals that rhodophyte mtDNAs are unusually uniform in size and gene order. Finally, phylogenetic analyses provide strong evidence that red algae share a common ancestry with green algae and plants.

Burger, G; Saint-Louis, D; Gray, M W; Lang, B F

1999-01-01

283

The Chloroplast Protein Translocation Complexes of Chlamydomonas reinhardtii: A Bioinformatic Comparison of Toc and Tic Components in Plants, Green Algae and Red Algae  

PubMed Central

The recently completed genome of Chlamydomonas reinhardtii was surveyed for components of the chloroplast protein translocation complexes. Putative components were identified using reciprocal BlastP searches with the protein sequences of Arabidopsis thaliana as queries. As a comparison, we also surveyed the new genomes of the bryophyte Physcomitrella patens, two prasinophyte green algae (Ostreococcus lucimarinus and Ostreococcus tauri), the red alga Cyanidioschizon merolae, and several cyanobacteria. Overall, we found that the components of the import pathway are remarkably well conserved, particularly among the Viridiplantae lineages. Specifically, C. reinhardtii contained almost all the components found in A. thaliana, with two exceptions. Missing from C. reinhardtii are the C-terminal ferredoxin-NADPH-reductase (FNR) binding domain of Tic62 and a full-length, TPR-bearing Toc64. Further, the N-terminal domain of C. reinhardtii Toc34 is highly acidic, whereas the analogous region in C. reinhardtii Toc159 is not. This reversal of the vascular plant model may explain the similarity of C. reinhardtii chloroplast transit peptides to mitochondrial-targeting peptides. Other findings from our genome survey include the absence of Tic22 in both Ostreococcus genomes; the presence of only one Toc75 homolog in C. merolae; and, finally, a distinctive propensity for gene duplication in P. patens.

Kalanon, Ming; McFadden, Geoffrey I.

2008-01-01

284

Investigation into the Optical Properties of Nanostructured Silica from Diatoms.  

National Technical Information Service (NTIS)

The overall objective of this project was to investigate the optical properties of silica isolated from the unicellular algae known as diatoms. The diatom species used in this study were Cylindrotheca fusiformis, Cyclotella meneghiana, Navicula pelliculos...

M. Hildebrand B. Palenik

2003-01-01

285

A cDNA coding for glutathione S-transferase from the unicellular green algae Coccomyxa sp.  

PubMed

A cDNA coding for glutathione S-transferase (GST) was cloned and sequenced from the unicellular green algae Coccomyxa sp. The predicted 215 amino acid polypeptide (23.9 kDa, pI 5.3) is most similar to the theta-type GSTs found in a variety of different eukaryotic organisms. Within this sub-class, the Coccomyxa GST is 42% identical (63% similar) to the flatfish Pleuronectes platessa homologue, and 24 to 35% (49-57%) to other theta-type GST's. PMID:8918264

Hiltonen, T; Clarke, A K; Karlsson, J; Samuelsson, G

1996-10-17

286

Occurrence of metallothionein gene smtA in synechococcus Tx-20 and other blue-green algae  

SciTech Connect

Blue-green algae are often abundant at Zn- and Cd-contaminated sites. In order to understand the mechanisms associated with Zn- and Cd-tolerance, we have isolated a metallothionein gene, designated smtA, in Synechococcus Tx-20 (- Pcc 6301 - Anacystis nidulans), a strain apparently obtained from an unpolluted site. The gene was cloned and sequenced, and its expression investigated in a range of heavy-metal-tolerant strains of the same organism obtained by stepwise adaptation. The polymerase chain reaction was used to probe for the possible presence of the homologous gene in a range of other strains (especially Synechococcus) isolated from sites without and with heavy metal contamination.

Robinson, N.J.; Gupta, A.; Huckle, J.W.; Jackson, P.; Whitton, B.A. (Univ. of Durham (England))

1990-06-01

287

The occurrence and biosynthesis of gamma-linolenic acid in a blue-green alga, Spirulina platensis  

Microsoft Academic Search

The acyl-lipid and fatty acid composition of six blue-green algae, namely,Spirulina platensis, Myxosarcina chroococcoides, Chlorogloea fritschii, Anabaena cylindrica, Anabaena flos-aquae, and Mastigocladus\\u000a laminosus is reported.\\u000a \\u000a All contain major proportions of mono-and digalactosyl diglyceride, sulfoquinovosyl diglyceride, and phosphatidyl glycerol,\\u000a but none possess lecithin, phophatidyl ethanolamine, or phosphatidyl inositol. Trans-3-hexadecenoic acid was absent from all\\u000a extracts.\\u000a \\u000a \\u000a \\u000a The analyses provide further evidence that

B. W. Nichols; B. J. B. Wood

1968-01-01

288

Combined effect of oil, oil products and dispersants on the blue-green algae Synechocystis aquatilis and Anabaena variabilis  

SciTech Connect

The study of the combined effect of oil, oil products and dispersants on the growth of the blue-green algae Synechocystis aquatilis and Anabaena variabilis has shown that out of 12 studied oil-dispersant pairs 6 revealed a positive relationship, which provides evidence for a decrease in oil and oil products toxic effect in the presence of a dispersant. The positive interaction between oil and oil products was found. The negative oil and oil products effect on all studied indices of A. variabilis culture increases with time.

Gapochka, L.D.; Brodskii, L.I.; Kravchenko, M.E.; Fedorov, V.D.

1980-01-01

289

Developing Molecular Genetic Tools to Facilitate Economic Production in Green Algae.  

National Technical Information Service (NTIS)

It is now accepted that algae have enormous potential to generate economically viable and environmentally sustainable liquid fuels that can help mitigate the effects of a diminishing supply of fossil fuel. The achievement of economic biofuel production fr...

D. R. Georgianna J. Gimpel M. J. Hannon S. P. Mayfield

2012-01-01

290

Characterisation of inorganic carbon fluxes, carbonic anhydrase(s) and ribulose-1,5-biphosphate carboxylase-oxygenase in the green unicellular alga Coccomyxa  

Microsoft Academic Search

Processes involved in the uptake and fixation of dissolved inorganic carbon (DIC) were characterised for Coccomyxa, the green algal primary photobiont of the lichen Peltigera aphthosa and compared with the freeliving alga Chlamydomonas reinhardtii Dangeard (WT cc 125+). A mass-spectrometer disequilibrium technique was used to quantify fluxes of both HCOinf3sup-and CO2 in the two algae, while activities of carbonic anhydrases

Kristin Palmqvist I; Dieter Siiltemeyer; Pierre Baldet; T. John Andrews; Murray R. Badger

1995-01-01

291

Localization and evolution of septins in algae.  

PubMed

Septins are a group of GTP-binding proteins that are multi-functional, with a well-known role in cytokinesis in animals and fungi. Although the functions of septins have been thoroughly studied in opisthokonts (fungi and animals), the function and evolution of plant/algal septins are not as well characterized. Here we describe septin localization and expression in the green algae Nannochloris bacillaris and Marvania geminata. The present data suggest that septins localize at the division site when cytokinesis occurs. In addition, we show that septin homologs may be found only in green algae, but not in other major plant lineages, such as land plants, red algae and glaucophytes. We also found other septin homolog-possessing organisms among the diatoms, Rhizaria and cryptomonad/haptophyte lineages. Our study reveals the potential role of algal septins in cytokinesis and/or cell elongation, and confirms that septin genes appear to have been lost in the Plantae lineage, except in some green algae. PMID:23398289

Yamazaki, Tomokazu; Owari, Satomi; Ota, Shuhei; Sumiya, Nobuko; Yamamoto, Maki; Watanabe, Koichi; Nagumo, Tamotsu; Miyamura, Shinichi; Kawano, Shigeyuki

2013-05-01

292

Diatoms in comets  

NASA Technical Reports Server (NTRS)

The fossil record of the microscopic algae classified as diatoms suggests they were injected to earth at the Cretaceous boundary. Not only could diatoms remain viable in the cometary environment, but also many species might replicate in illuminated surface layers or early interior layers of cometary ice. Presumably they reached the solar system on an interstellar comet as an already-evolved assemblage of organisms. Diatoms might cause color changes to comet nuclei while their outgassing decays and revives around highly elliptical orbits. Just as for interstellar absorption, high-resolution IR observations are capable of distinguishing whether the 10-micron feature arises from siliceous diatom material or mineral silicates. The 10-30-micron band and the UV 220-nm region can also provide evidence of biological material.

Hoover, R.; Hoyle, F.; Wallis, M. K.; Wickramasinghe, N. C.

1986-01-01

293

The GC-rich mitochondrial and plastid genomes of the green alga Coccomyxa give insight into the evolution of organelle DNA nucleotide landscape.  

PubMed

Most of the available mitochondrial and plastid genome sequences are biased towards adenine and thymine (AT) over guanine and cytosine (GC). Examples of GC-rich organelle DNAs are limited to a small but eclectic list of species, including certain green algae. Here, to gain insight in the evolution of organelle nucleotide landscape, we present the GC-rich mitochondrial and plastid DNAs from the trebouxiophyte green alga Coccomyxa sp. C-169. We compare these sequences with other GC-rich organelle DNAs and argue that the forces biasing them towards G and C are nonadaptive and linked to the metabolic and/or life history features of this species. The Coccomyxa organelle genomes are also used for phylogenetic analyses, which highlight the complexities in trying to resolve the interrelationships among the core chlorophyte green algae, but ultimately favour a sister relationship between the Ulvophyceae and Chlorophyceae, with the Trebouxiophyceae branching at the base of the chlorophyte crown. PMID:21887287

Smith, David Roy; Burki, Fabien; Yamada, Takashi; Grimwood, Jane; Grigoriev, Igor V; Van Etten, James L; Keeling, Patrick J

2011-01-01

294

The GC-Rich Mitochondrial and Plastid Genomes of the Green Alga Coccomyxa Give Insight into the Evolution of Organelle DNA Nucleotide Landscape  

PubMed Central

Most of the available mitochondrial and plastid genome sequences are biased towards adenine and thymine (AT) over guanine and cytosine (GC). Examples of GC-rich organelle DNAs are limited to a small but eclectic list of species, including certain green algae. Here, to gain insight in the evolution of organelle nucleotide landscape, we present the GC-rich mitochondrial and plastid DNAs from the trebouxiophyte green alga Coccomyxa sp. C-169. We compare these sequences with other GC-rich organelle DNAs and argue that the forces biasing them towards G and C are nonadaptive and linked to the metabolic and/or life history features of this species. The Coccomyxa organelle genomes are also used for phylogenetic analyses, which highlight the complexities in trying to resolve the interrelationships among the core chlorophyte green algae, but ultimately favour a sister relationship between the Ulvophyceae and Chlorophyceae, with the Trebouxiophyceae branching at the base of the chlorophyte crown.

Smith, David Roy; Burki, Fabien; Yamada, Takashi; Grimwood, Jane; Grigoriev, Igor V.; Van Etten, James L.; Keeling, Patrick J.

2011-01-01

295

Effect of petroleum hydrocarbons on algae  

SciTech Connect

Algal species (65) were isolated from oil refinery effluent. Twenty-five of these species were cultured in Benecke's medium in a growth chamber, along with controls. Retardation in algal growth, inhibition in algal photosynthesis, and discoloration was observed in petroleum enriched medium. Few forms, viz. Cyclotella sp., Cosmarium sp., and Merismopedia sp. could not survive. The lag phase lengthened by several days and slope of exponential phase was also depressed. Chlamydomonas sp., Scenedesmus sp., Ankistrodesmus sp., Nitzschia sp. and Navicula sp. were comparatively susceptible to petroleum. Depression in carbon fixation, cell numbers, and total dry algal mass was noticeable, showing toxicity to both diatoms and green algae.

Bhadauria, S. (Raja Balwant Singh College, Agra (India)); Sengar, R.M.S. (Agra College (India)); Mittal, S.; Bhattacharjee, S. (IARI, New Delhi (India))

1992-01-01

296

Ribosomal protein L10 is encoded in the mitochondrial genome of many land plants and green algae  

PubMed Central

Background The mitochondrial genomes of plants generally encode 30-40 identified protein-coding genes and a large number of lineage-specific ORFs. The lack of wide conservation for most ORFs suggests they are unlikely to be functional. However, an ORF, termed orf-bryo1, was recently found to be conserved among bryophytes suggesting that it might indeed encode a functional mitochondrial protein. Results From a broad survey of land plants, we have found that the orf-bryo1 gene is also conserved in the mitochondria of vascular plants and charophycean green algae. This gene is actively transcribed and RNA edited in many flowering plants. Comparative sequence analysis and distribution of editing suggests that it encodes ribosomal protein L10 of the large subunit of the ribosome. In several lineages, such as crucifers and grasses, where the rpl10 gene has been lost from the mitochondrion, we suggest that a copy of the nucleus-encoded chloroplast-derived rpl10 gene may serve as a functional replacement. Conclusion Despite the fact that there are now over 20 mitochondrial genome sequences for land plants and green algae, this gene has remained unidentified and largely undetected until now because of the unlikely coincidence that most of the earlier sequences were from the few lineages that lack the intact gene. These results illustrate the power of comparative sequencing to identify novel genomic features.

2009-01-01

297

Zeta potential measurement on the surface of blue-green algae particles for micro-bubble process.  

PubMed

Any kind of blue-green alga produces metabolites of musty substances and toxins. Therefore, it is necessary to remove the blue-green algae, and processing also including nutrient removal is desired for the water quality improvement of eutrophic lakes. The purpose of this study has been to investigate the possibility of a flotation system using a hybrid technique (chemical compounds and electrostatic bridge) applied to raw water containing phytoplankton with high pH of water, and to examine the zeta potential value of phytoplankton surface and the removal efficiency for phytoplankton, ammonia, nitrogen, and phosphoric acid. The results were as follows: firstly, zeta potential of M. aeruginosa particles was observed to achieve charge neutralization on their surface by adhesion of magnesium hydroxide precipitation with increasing pH. Secondly, maximum removal efficiency concerning chlorophyll-a was observed as 84%, and this efficiency was obtained in the condition of pH > 10, and magnesium hydroxide precipitation was observed. Thirdly, in the pH condition that the maximum removal efficiency of chlorophyll-a was obtained, the removal efficiency and the amount of decrease of NH(4)-N and PO(4)-P before and after the change of pH values were observed as 6.7% (0.04 mg-P/L) and 63.6% (0.07 mg-N/L), respectively. PMID:18192736

Taki, Kazuo; Seki, Tatsuhiro; Mononobe, Sakiyori; Kato, Kohichi

2008-01-01

298

Antiviral activity of acidic polysaccharides from Coccomyxa gloeobotrydiformi, a green alga, against an in vitro human influenza A virus infection.  

PubMed

The extracts prepared from green algae are reported to possess a variety of biological activities including antioxidant, antitumor and antiviral activities. The acidic polysaccharide fraction from a green alga Coccomyxa gloeobotrydiformi (CmAPS) was isolated and the antiviral action on an in vitro infection of influenza A virus was examined. CmAPS inhibited the growth and yield of all influenza A virus strains tested, such as A/H1N1, A/H2N2, A/H3N2 and A/H1N1 pandemic strains. The 50% inhibitory concentration of CmAPS on the infection of human influenza A virus strains ranged from 26 to 70 µg/mL and the antiviral activity of CmAPS against influenza A/USSR90/77 (H1N1) was the strongest. The antiviral activity of CmAPS was not due to the cytotoxicity against host cells. The antiviral activity of CmAPS required its presence in the inoculation of virus onto MDCK cells. Pretreatment and post-treatment with CmAPS was ineffective for the antiviral activity. CmAPS inhibited influenza A virus-induced erythrocyte hemagglutination and hemolysis. Taken together, CmAPS was suggested to exhibit the anti-influenza virus activity through preventing the interaction of virus and host cells. The detailed antiviral activity of CmAPS is discussed. PMID:22856509

Komatsu, Takayuki; Kido, Nobuo; Sugiyama, Tsuyoshi; Yokochi, Takashi

2013-02-01

299

New "missing link" genus of the colonial volvocine green algae gives insights into the evolution of oogamy  

PubMed Central

Background The evolution of oogamy from isogamy, an important biological event, can be summarized as follows: morphologically similar gametes (isogametes) differentiated into small “male” and large “female” motile gametes during anisogamy, from which immotile female gametes (eggs) evolved. The volvocine green algae represent a model lineage to study this type of sex evolution and show two types of gametic unions: conjugation between isogametes outside the parental colonies (external fertilization during isogamy) and fertilization between small motile gametes (sperm) and large gametes (eggs) inside the female colony (internal fertilization during anisogamy and oogamy). Although recent cultural studies on volvocine algae revealed morphological diversity and molecular genetic data of sexual reproduction, an intermediate type of union between these two gametic unions has not been identified. Results We identified a novel colonial volvocine genus, Colemanosphaera, which produces bundles of spindle-shaped male gametes through successive divisions of colonial cells. Obligately anisogamous conjugation between male and female motile gametes occurred outside the female colony (external fertilization during anisogamy). This new genus contains 16- or 32-celled spheroidal colonies similar to those of the volvocine genera Yamagishiella and Eudorina. However, Colemanosphaera can be clearly distinguished from these two genera based on its sister phylogenetic position to the enigmatic flattened colonial volvocine Platydorina and external fertilization during anisogamy. Two species of Colemanosphaera were found in a Japanese lake; these species are also distributed in European freshwaters based on a published sequence of an Austrian strain and the original description of Pandorina charkowiensis from Ukraine. Conclusions Based on phylogeny and morphological data, this novel genus exhibits a missing link between Platydorina and the typical spheroidal colonial volvocine members such as Pandorina or Yamagishiella. Considering the external obligate anisogamy, oogamy evolution may have been preceded by the transition from external to internal fertilization during anisogamy within the volvocine green algae.

2014-01-01

300

Three-dimensional ultrastructural study of oil and astaxanthin accumulation during encystment in the green alga Haematococcus pluvialis.  

PubMed

Haematococcus pluvialis is a freshwater species of green algae and is well known for its accumulation of the strong antioxidant astaxanthin, which is used in aquaculture, various pharmaceuticals, and cosmetics. High levels of astaxanthin are present in cysts, which rapidly accumulate when the environmental conditions become unfavorable for normal cell growth. It is not understood, however, how accumulation of high levels of astaxanthin, which is soluble in oil, becomes possible during encystment. Here, we performed ultrastructural 3D reconstruction based on over 350 serial sections per cell to visualize the dynamics of astaxanthin accumulation and subcellular changes during the encystment of H. pluvialis. This study showcases the marked changes in subcellular elements, such as chloroplast degeneration, in the transition from green coccoid cells to red cyst cells during encystment. In green coccoid cells, chloroplasts accounted for 41.7% of the total cell volume, whereas the relative volume of astaxanthin was very low (0.2%). In contrast, oil droplets containing astaxanthin predominated in cyst cells (52.2%), in which the total chloroplast volume was markedly decreased (9.7%). Volumetric observations also demonstrated that the relative volumes of the cell wall, starch grains, pyrenoids, mitochondria, the Golgi apparatus, and the nucleus in a cyst cell are smaller than those in green coccid cells. Our data indicated that chloroplasts are degraded, resulting in a net-like morphology, but do not completely disappear, even at the red cyst stage. PMID:23326471

Wayama, Marina; Ota, Shuhei; Matsuura, Hazuki; Nango, Nobuhito; Hirata, Aiko; Kawano, Shigeyuki

2013-01-01

301

Three-Dimensional Ultrastructural Study of Oil and Astaxanthin Accumulation during Encystment in the Green Alga Haematococcus pluvialis  

PubMed Central

Haematococcus pluvialis is a freshwater species of green algae and is well known for its accumulation of the strong antioxidant astaxanthin, which is used in aquaculture, various pharmaceuticals, and cosmetics. High levels of astaxanthin are present in cysts, which rapidly accumulate when the environmental conditions become unfavorable for normal cell growth. It is not understood, however, how accumulation of high levels of astaxanthin, which is soluble in oil, becomes possible during encystment. Here, we performed ultrastructural 3D reconstruction based on over 350 serial sections per cell to visualize the dynamics of astaxanthin accumulation and subcellular changes during the encystment of H. pluvialis. This study showcases the marked changes in subcellular elements, such as chloroplast degeneration, in the transition from green coccoid cells to red cyst cells during encystment. In green coccoid cells, chloroplasts accounted for 41.7% of the total cell volume, whereas the relative volume of astaxanthin was very low (0.2%). In contrast, oil droplets containing astaxanthin predominated in cyst cells (52.2%), in which the total chloroplast volume was markedly decreased (9.7%). Volumetric observations also demonstrated that the relative volumes of the cell wall, starch grains, pyrenoids, mitochondria, the Golgi apparatus, and the nucleus in a cyst cell are smaller than those in green coccid cells. Our data indicated that chloroplasts are degraded, resulting in a net-like morphology, but do not completely disappear, even at the red cyst stage.

Matsuura, Hazuki; Nango, Nobuhito; Hirata, Aiko; Kawano, Shigeyuki

2013-01-01

302

The effects of phosphate on the biomineralization of the green alga, Halimeda incrassata (Ellis) Lam  

Microsoft Academic Search

Field surveys indicated that individuals of Halimeda incrassata (Ellis) Lamouroux, a rhizophytic alga, were significantly more mineralized when collected from phosphate-limited carbonate sediments of the Florida Keys than those collected from siliciclastic sediments at Tarpon Springs on the west coast of Florida. Results from field experiments in Tarpon Springs, which compared growth of H. incrassata in enriched conditions to unmanipulated

Kyle W. Demes; Susan S. Bell; Clinton J. Dawes

2009-01-01

303

Extraction of pigments and fatty acids from the green alga Scenedesmus obliquus (Chlorophyceae)  

Microsoft Academic Search

In this paper, the efficiency of pigment and fatty acid extraction from resistant algae using Scenedesmus obliquus as an example was examined. We found that adding quartz sand and solvent to freeze-dried algal material and subsequent extraction in an ultrasound bath for 90min at -4?°C resulted in excellent extraction of these compounds. This extraction method was compared with a method

Karen H. Wiltshire; Maarten Boersma; Anita Möller; Heinke Buhtz

2000-01-01

304

Blue-green algae associated with ascidians of the Great Barrier Reef  

Microsoft Academic Search

IN the rich biota of reef communities, one of the best known symbiotic relationships is that of dinoflagellates known as ``zooxanthellae'' with corals and giant clams1-3. In contrast, the presence of algae in ascidians (sea squirts: Phylum Chordata, Subphylum Tunicata), although known for many years, has been studied very little. It is known that the association is confined to tropical

Eldon H. Newcomb; Thomas D. Pugh

1975-01-01

305

Adsorption of heavy metals by green algae and ground rice hulls  

Microsoft Academic Search

This research demonstrates the applicability of low cost, readily available alternate adsorbents to remove and recover toxic heavy metals from water. Heavy metal ion adsorption has been investigated using two different adsorbing biomasses, algae and rice hulls. Algal biomass adsorption studies were conducted with: As, Cd, Co, Cr, Pb, Ni and Zn, and rice hull biomass adsorption studies were conducted

Dipak Roy; Paul N. Greenlaw; Barbara S. Shane

1993-01-01

306

Isolation of clonal cultures of endosymbiotic green algae from their ciliate hosts.  

PubMed

Using Paramecium bursaria as a model organism improved protocols have been developed to isolate clonal endosymbiotic algae. This involved micromanipulation of individual protists, rupturing to release endosymbionts followed by enrichment on complex media and a series of plating steps, under low light (PAR ~10?mol photons m(-2)s(-1)). PMID:23337811

Achilles-Day, Undine E M; Day, John G

2013-03-01

307

Food production and gas exchange system using blue-green alga (Spirulina) for CELSS  

Microsoft Academic Search

In order to reduce the cultivation area required for the growth of higher plants in space adoption of algae, which have a higher photosynthetic ability, seems very suitable for obtaining oxygen and food as a useful source of high quality protein. The preliminary cultivation experiment for determining optimum cultivation conditions and for obtaining the critical design parameters of the cultivator

Mitsuo Oguchi; Koji Otsubo; Keiji Nitta; Shigeki Hatayama

1987-01-01

308

Some metabolic activities in the green alga Scenedesmus bijuga as affected by the insecticide trichlorfon  

Microsoft Academic Search

Summary This investigation studied the effects of trichlorfon on the growth and some physiological activities of the common freshwater alga Scenedesmus bijuga in the River Nile. The results showed that the cell number and Chl. a content of Scenedesmus bijuga decreased with increase in trichlorfon concentration. The data also showed that the total carbohydrate contents of Scenedesmus bijuga increased following

Adel A. Fathi

2003-01-01

309

Lipophilic pigments from cyanobacterial (blue-green algal) and diatom mats in Hamelin Pool, Shark Bay, Western Australia  

NASA Technical Reports Server (NTRS)

Lipophilic pigments were examined in microbial mat communities dominated by cyanobacteria in the intertidal zone and by diatoms in the subtidal and sublittoral zones of Hamelin Pool, Shark Bay, Western Australia. These microbial mats have evolutionary significance because of their similarity to lithfied stromatolites from the Proterozoic and Early Paleozoic eras. Fucoxanthin, diatoxanthin, diadinoxanthin, beta-carotene, and chlorophylls a and c characterized the diatom mats, whereas cyanobacterial mats contained myxoxanthophyll, zeaxanthin, echinenone, beta-carotene, chlorophyll a and, in some cases, sheath pigment. The presence of bacteriochlorophyll a within the mats suggest a close association of photosynthetic bacteria with diatoms and cyanobacteria. The high carotenoids : chlorophyll a ratios (0.84-2.44 wt/wt) in the diatom mats suggest that carotenoids served a photoprotective function in this high light environment. By contrast, cyanobacterial sheath pigment may have largely supplanted the photoprotective role of carotenoids in the intertidal mats.

Palmisano, A. C.; Summons, R. E.; Cronin, S. E.; Des Marais, D. J.

1989-01-01

310

Biosynthetic pathway and health benefits of fucoxanthin, an algae-specific xanthophyll in brown seaweeds.  

PubMed

Fucoxanthin is the main carotenoid produced in brown algae as a component of the light-harvesting complex for photosynthesis and photoprotection. In contrast to the complete elucidation of the carotenoid biosynthetic pathways in red and green algae, the biosynthetic pathway of fucoxanthin in brown algae is not fully understood. Recently, two models for the fucoxanthin biosynthetic pathway have been proposed in unicellular diatoms; however, there is no such information for the pathway in brown seaweeds to date. Here, we propose a biosynthetic pathway for fucoxanthin in the brown seaweed, Ectocarpus siliculosus, derived from comparison of carotenogenic genes in its sequenced genome with those in the genomes of two diatoms, Thalassiosira pseudonana and Phaeodactylum tricornutum. Currently, fucoxanthin is receiving attention, due to its potential benefits for human health. Therefore, new knowledge regarding the medical and nutraceutical properties of fucoxanthin from brown seaweeds is also summarized here. PMID:23820585

Mikami, Koji; Hosokawa, Masashi

2013-01-01

311

Biosynthetic Pathway and Health Benefits of Fucoxanthin, an Algae-Specific Xanthophyll in Brown Seaweeds  

PubMed Central

Fucoxanthin is the main carotenoid produced in brown algae as a component of the light-harvesting complex for photosynthesis and photoprotection. In contrast to the complete elucidation of the carotenoid biosynthetic pathways in red and green algae, the biosynthetic pathway of fucoxanthin in brown algae is not fully understood. Recently, two models for the fucoxanthin biosynthetic pathway have been proposed in unicellular diatoms; however, there is no such information for the pathway in brown seaweeds to date. Here, we propose a biosynthetic pathway for fucoxanthin in the brown seaweed, Ectocarpus siliculosus, derived from comparison of carotenogenic genes in its sequenced genome with those in the genomes of two diatoms, Thalassiosira pseudonana and Phaeodactylum tricornutum. Currently, fucoxanthin is receiving attention, due to its potential benefits for human health. Therefore, new knowledge regarding the medical and nutraceutical properties of fucoxanthin from brown seaweeds is also summarized here.

Mikami, Koji; Hosokawa, Masashi

2013-01-01

312

Comparative efficiency of Azolla, blue-green algae and other organic manures in relation to N and P availability in a flooded rice soil  

Microsoft Academic Search

Summary Pot incubation study with fresh Azolla (Azolla pinnata-India and Vietnam isolates,A. mexicana andA. filiculoides), blue-green algaAulosira sp., green manureSesbania cannabina, Azolla compost, farm yard manure and ammonium sulphate was conducted under flooded condition at CRRI, Cuttack keeping an equivalent amount of 25 ppm N through all the amendments where changes in availability of N and P, C?N ratio and

P. K. Singh; B. C. Panigrahi; K. B. Satapathy

1981-01-01

313

Involvement of zeaxanthin and of the Cbr protein in the repair of photosystem II from photoinhibition in the green alga Dunaliella salina  

Microsoft Academic Search

A light-sensitive and chlorophyll (Chl)-deficient mutant of the green alga Dunaliella salina (dcd1) showed an amplified response to irradiance stress compared to the wild-type. The mutant was yellow–green under low light (100 ?mol photons m?2 s?1) and yellow under high irradiance (2000 ?mol photons m?2 s?1). The mutant had lower levels of Chl, lower levels of light harvesting complex II,

EonSeon Jin; Juergen E. W. Polle; Anastasios Melis

2001-01-01

314

The GC-Rich Mitochondrial and Plastid Genomes of the Green Alga Coccomyxa Give Insight into the Evolution of Organelle DNA Nucleotide Landscape  

Microsoft Academic Search

Most of the available mitochondrial and plastid genome sequences are biased towards adenine and thymine (AT) over guanine and cytosine (GC). Examples of GC-rich organelle DNAs are limited to a small but eclectic list of species, including certain green algae. Here, to gain insight in the evolution of organelle nucleotide landscape, we present the GC-rich mitochondrial and plastid DNAs from

David Roy Smith; Fabien Burki; Takashi Yamada; Jane Grimwood; Igor V. Grigoriev; James L. van Etten; Patrick J. Keeling; Juergen Kroymann

2011-01-01

315

Variation of heavy metal contents of the green alga Caulerpa Taxifolia (VAHL) C. Agardh in its area of expansion in the French Mediterranean Sea  

Microsoft Academic Search

Concentrations in cadmium, copper, mercury, nickel, lead and zinc were determined by atomic absorption spectrophotometry in 72 samples of the green alga Caulerpa taxifolia collected in its area of expansion in the French Mediterranean Sea. The data obtained was used to carry out a statistical study on the two main parts of the thallus (pseudo?stolons and pseudo?leaves), in regard to

H. Augier; J. DOrso; N. le Tallec; G. Ramonda

1999-01-01

316

The ultrastructure of the marine blue green alga, Trichodesmium erythraeum , with special reference to the cell wall, gas vacuoles, and cylindrical bodies  

Microsoft Academic Search

The marine blue green alga, Trichodesmium erythraeum, was studied with electron microscopy in an attempt to elucidate the structural basis for its rapid lysis when removed from its marine environment. In this connection, it was found that a thining of the electron-dense layer of the longitudinal wall at the site adjacent to transverse wall attachment was responsible for lysis. The

Chase Baalen; R. Malcolm Brown

1969-01-01

317

Regulation of Two Carotenoid Biosynthesis Genes Coding for Phytoene Synthase and Carotenoid Hydroxylase during Stress-Induced Astaxanthin Formation in the Green Alga Haematococcus pluvialis  

Microsoft Academic Search

Astaxanthin is a high-value carotenoid used as a pigmentation source in fish aquaculture. In addition, a beneficial role of astaxanthin as a food supplement for humans is becoming evident. The unicellular green alga Haematococcus pluvialis seems to be a suitable source for natural astaxanthin. Astaxanthin accumulation in H. pluvialis occurs in response to environmental stress such as high light and

Jens Steinbrenner; Hartmut Linden

2001-01-01

318

Effects of brefeldin A on the Golgi apparatus, the nuclear envelope, and the endoplasmic reticulum in a green alga, Scenedesmus acutus  

Microsoft Academic Search

Summary The effects of brefeldin A (BFA) on the structure of the Golgi apparatus, the nuclear envelope, and the endoplasmic reticulum (ER), and on the thiamine pyrophosphatase (TPPase) activity in these organelles were examined in a green alga,Scenedesmus acutus, to obtain evidence for the existence of a retrograde transport from the Golgi apparatus to the ER via the nuclear envelope.

T. Noguchi; H. Watanabe; R. Suzuki

1998-01-01

319

Phototropin is the blue-light receptor that controls multiple steps in the sexual life cycle of the green alga Chlamydomonas reinhardtii  

Microsoft Academic Search

Blue light as an environmental cue plays a pivotal role in controlling the progression of the sexual life cycle in the green alga Chlamydomonas reinhardtii. Phototropin was considered a prime candidate for the blue-light receptor involved. By using the RNA interference method, knockdown strains with reduced phototropin levels were isolated. Those with severely reduced levels of this photoreceptor were partially

Kaiyao Huang; Christoph F. Beck

2003-01-01

320

Draft Genome Sequence of Pseudomonas pelagia CL-AP6, a Psychrotolerant Bacterium Isolated from Culture of Antarctic Green Alga Pyramimonas gelidicola.  

PubMed

Pseudomonas pelagia CL-AP6, isolated from a culture of the Antarctic green alga Pyramimonas gelidicola, is a psychrotolerant bacterium. Here, we report the draft genome sequence of this strain, which may provide insights into the mutualistic interaction between microalgae and bacteria in sea ice, as well as the cold adaptation mechanisms of bacteria. PMID:24009125

Koh, Hye Yeon; Jung, Woongsic; Do, Hackwon; Lee, Sung Gu; Lee, Jun Hyuck; Kim, Hak Jun

2013-01-01

321

Determination of growth rate depression of some green algae by atrazine  

SciTech Connect

A common contaminant of surface waters of agricultural regions is the triazine herbicide, atrazine (2-chloro-4-ethylamino-6-isoproplyamino-s-triazine). Atrazine effectively inhibits growth and photosynthesis of most plants, including freshwater algae. Both depression of growth rate and reduced yield have been used as parameters in studies of the effects of atrazine on algal growth. Considerable variation exists among algal toxicity methods despite attempts at standardization. Experimental endpoints range from percent inhibitions to EC50s. Algae from two different Iowa springs were the subjects of a study of naturally occurring atrazine tolerance. The authors report here the results of two aspects of that study: development of a quick method of assessing toxin effects on algal growth, and investigation of a ecologically meaningful endpoint for toxin-growth experiments.

Hersh, C.M.; Crumpton, W.G.

1987-12-01

322

Effect of nutrients on growth and lipid accumulation in the green algae Dunaliella tertiolecta.  

PubMed

Production of biofuel from algae is dependent on the microalgal biomass production rate and lipid content. Both biomass production and lipid accumulation are limited by several factors, of which nutrients play a key role. In this research, the marine microalgae Dunaliella tertiolecta was used as a model organism and a profile of its nutritional requirements was determined. Inorganic phosphate PO4(3-) and trace elements: cobalt (Co2+), iron (Fe3+), molybdenum (Mo2+) and manganese (Mn2+) were identified as required for algae optimum growth. Inorganic nitrogen in the form of nitrate NO3- instead of ammonium (NH4+) was required for maximal biomass production. Lipids accumulated under nitrogen starvation growth condition and this was time-dependent. Results of this research can be applied to maximize production of microalgal lipids in optimally designed photobioreactors. PMID:20947341

Chen, Meng; Tang, Haiying; Ma, Hongzhi; Holland, Thomas C; Ng, K Y Simon; Salley, Steven O

2011-01-01

323

Promotive effect of se on the growth and antioxidation of a blue-green alga Spirulina maxima  

NASA Astrophysics Data System (ADS)

Cultures of a blue-green alga Spirulina maxima (Setch. et Gard.) Geitler with various concentrations of Se in Zarrouk's medium showed that not higher than 40 mg/L Se could promote its growth. The present experiments showed that S. maxima grown under normal conditions, has an oxidant stress defence system for hydrogen peroxide (H2O2) removal, which is the Halliwell-Asada pathway. When 4 to 20 mg/L Se was added to the algal medium, this pathway was replaced by a so-called Sestressed pathway containing GSH peroxidase (GSH-POD). As a result of the occurrence of both higher activity of GSH-POD and lower levels of hydroxyl radical (OH·), the Se-stressed pathway scavenged H2O2 so effectively that the growth of S. maxima was promoted by 4 to 20 mg/L Se. While GSH-POD activity of the alga disappeared at 40 mg/L Se, the recovery of ascorbate peroxidase was observed. The lower levels of ascorbic acid and GSH made the Halliwell-Asada pathway for scavenging H2O2 less effective, while the highest activity of catalase might be responsible in part for the H2O2 removal, causing the level of OH· in S. maxima grown at 40 mg/L Se to be much higher than the OH· level in this alga grown at 4 to 20 mg/L Se, but lower than that in the control. The OH· level changes caused the growth of S. maxima cultured at 40 mg/L Se to increase slightly to close to that of the control.

Zhi-Gang, Zhou; Zhi-Li, Liu

1998-12-01

324

Influence of PbS nanoparticle polymer coating on their aggregation behavior and toxicity to the green algae Dunaliella salina.  

PubMed

The potential hazards of nanoparticles (NPs) to the environment and to living organisms need to be considered for a safe development of nanotechnology. In the present study, the potential toxic effects of uncoated and gum Arabic-coated lead sulfide nanoparticles (GA-coated PbS NPs) on the growth, lipid peroxidation, reducing capacity and total carotenoid content of the hypersaline unicellular green algae Dunaliella salina were investigated. Coatings of PbS NPs with GA, as confirmed by Fourier transform infrared spectroscopy, reduced the toxicity of PbS NPs. Uncoated PbS NP toxicity to D. salina was attributed to higher algal cell-NP agglomerate formation, higher lipid peroxidation, lower content of total reducing substances and lower total carotenoid content. Low levels of Pb(2+) in the growth culture media indicate that PbS NP dissolution does not occur in the culture. Also, the addition of 100?M Pb(2+) to the culture media had no significant (P>0.05) effect on algal growth. The shading of light (shading effect) by PbS NPs, when simulated using activated charcoal, did not contribute to the overall toxic effect of PbS NPs which was evident by insignificant (P>0.05) reduction in the growth and antioxidant capacity of the algae. When PbS NP aggregation in culture media (without algal cells) was followed for 60min, uncoated form aggregated rapidly reaching aggregate sizes with hydrodynamic diameter of over 2500nm within 60min. Effective particle-particle interaction was reduced in the GA-coated NPs. Aggregates of about 440nm hydrodynamic diameter were formed within 35min. Afterwards the aggregate size remained constant. It is concluded that PbS NPs have a negative effect on aquatic algae and their transformation by GA capping affects NPs aggregation properties and toxicity. PMID:24907922

Zamani, Hajar; Moradshahi, Ali; Jahromi, Hamed Dehdashti; Sheikhi, Mohammad Hosein

2014-09-01

325

Cellulose Synthase (CesA) Genes in the Green Alga Mesotaenium caldariorum  

PubMed Central

Cellulose, a microfibrillar polysaccharide consisting of bundles of ?-1,4-glucan chains, is a major component of plant and most algal cell walls and is also synthesized by some prokaryotes. Seed plants and bacteria differ in the structures of their membrane terminal complexes that make cellulose and, in turn, control the dimensions of the microfibrils produced. They also differ in the domain structures of their CesA gene products (the catalytic subunit of cellulose synthase), which have been localized to terminal complexes and appear to help maintain terminal complex structure. Terminal complex structures in algae range from rosettes (plant-like) to linear forms (bacterium-like). Thus, algal CesA genes may reveal domains that control terminal complex assembly and microfibril structure. The CesA genes from the alga Mesotaenium caldariorum, a member of the order Zygnematales, which have rosette terminal complexes, are remarkably similar to seed plant CesAs, with deduced amino acid sequence identities of up to 59%. In addition to the putative transmembrane helices and the D-D-D-QXXRW motif shared by all known CesA gene products, M. caldariorum and seed plant CesAs share a region conserved among plants, an N-terminal zinc-binding domain, and a variable or class-specific region. This indicates that the domains that characterize seed plant CesAs arose prior to the evolution of land plants and may play a role in maintaining the structures of rosette terminal complexes. The CesA genes identified in M. caldariorum are the first reported for any eukaryotic alga and will provide a basis for analyzing the CesA genes of algae with different types of terminal complexes.

Roberts, Alison W.; Roberts, Eric M.; Delmer, Deborah P.

2002-01-01

326

Cellulose synthase (CesA) genes in the green alga Mesotaenium caldariorum.  

PubMed

Cellulose, a microfibrillar polysaccharide consisting of bundles of beta-1,4-glucan chains, is a major component of plant and most algal cell walls and is also synthesized by some prokaryotes. Seed plants and bacteria differ in the structures of their membrane terminal complexes that make cellulose and, in turn, control the dimensions of the microfibrils produced. They also differ in the domain structures of their CesA gene products (the catalytic subunit of cellulose synthase), which have been localized to terminal complexes and appear to help maintain terminal complex structure. Terminal complex structures in algae range from rosettes (plant-like) to linear forms (bacterium-like). Thus, algal CesA genes may reveal domains that control terminal complex assembly and microfibril structure. The CesA genes from the alga Mesotaenium caldariorum, a member of the order Zygnematales, which have rosette terminal complexes, are remarkably similar to seed plant CesAs, with deduced amino acid sequence identities of up to 59%. In addition to the putative transmembrane helices and the D-D-D-QXXRW motif shared by all known CesA gene products, M. caldariorum and seed plant CesAs share a region conserved among plants, an N-terminal zinc-binding domain, and a variable or class-specific region. This indicates that the domains that characterize seed plant CesAs arose prior to the evolution of land plants and may play a role in maintaining the structures of rosette terminal complexes. The CesA genes identified in M. caldariorum are the first reported for any eukaryotic alga and will provide a basis for analyzing the CesA genes of algae with different types of terminal complexes. PMID:12477785

Roberts, Alison W; Roberts, Eric M; Delmer, Deborah P

2002-12-01

327

Elliptochloris bilobata var. corticola var. nov. (Trebouxiophyceae, Chlorophyta), a novel subaerial coccal green alga  

Microsoft Academic Search

We investigated a previously unidentified subaerial corticolous strain of the genus Elliptochloris Tschermak-Woess. The alga shares the generic morphological characters with Elliptochloris bilobata, the type species of the genus, but it has a thicker cell wall of adult globular cells, different chloroplast structure and\\u000a it also differs in shape of elliptical autospores. The differences of the autospore shape between both

Marek Eliáš; Ji?í Neustupa; Pavel Škaloud

2008-01-01

328

The influence of nitrogen on heterocyst production in blue-green algae  

Microsoft Academic Search

A series of experiments on heterocyst production in Anabaena uariabilis provides some strong indirect evidence for the role of heterocysts in nitrogen fixation. Of the algae tested (Anabaena uariabilk, A. inuequalis, A. cylindrica, A. flos-aquae, Tolypothrix distorta, Gloeotrichia echinulata, Aphaninomenon flos-aquae, Oscillatoria sp., and Microcystis aeru- ginosa), only those with heterocysts grew in a nitrate-free medium. Growth in the nitrate-

ROANN E. OGAWA; JOHN F. C CARR

1969-01-01

329

An investigation of glycolate excretion in two species of blue-green algae  

Microsoft Academic Search

The amount of 14C-glycolate excreted by Oscillatoria sp. and Anabaena flos-aquae is less than 1% of the 14C fixed by the algae during photosynthesis. Transfer of cells grown on 5% CO2 in air to a medium of low bicarbonate concentration or treatment of the cells with isonicotinyl hydrazide (INH) during photosynthesis, caused little increase in glycolate excretion. a-Hydroxysulfonates failed to

K. H. Cheng; A. G. Miller; Brian Colman

1972-01-01

330

Effect of pesticides on blue-green algae and nitrogen-fixation  

Microsoft Academic Search

The effects of the pesticides, amitrol, a derivative of amitrol (viz. 3,5-diamino-1,2,4-triazole), diquat, paraquat, linuron, MCPA, malathion, and monuron, were studied on the nitrogen-fixing algae,Anabaena cylindrica, Aulosira sp.,Calothrix elenkenii, Chlorogloeae fritschii, Cylindrospermum muscicola, Nostoc sp. fromCollema tenax, Nostoc muscorum, Tolypothrix tenuis, andWestiellopsis sp. In general, two types of response were discernible; an initial period of depression succeeded by an increased

Edgar J. DaSilva; Lars Eric Henriksson; Elisabet Henriksson

1975-01-01

331

Comparative effects of the blue green algae Nodularia spumigena and a lysed extract on detoxification and antioxidant enzymes in the green lipped mussel (Perna viridis).  

PubMed

Nodularia spumigena periodically proliferates to cause toxic algal blooms with some aquatic animals enduring and consuming high densities of the blue green algae or toxic lysis. N. spumigena contains toxic compounds such as nodularin and lipopolysaccharides. This current work investigates physiological effects of exposure from bloom conditions of N. spumigena cells and a post-bloom lysis. Biochemical and antioxidative biomarkers were comparatively studied over an acute 3-day exposure. In general, a post-bloom N. spumigena lysis caused opposite physiological responses to bloom densities of N. spumigena. Specifically, increases in glutathione (GSH) and glutathione peroxidase (GPx) and decreases in glutathione S-transferase (GST) were observed from the N. spumigena lysis. In contrast, N. spumigena cell densities decreased GSH and increased GST and lipid peroxidation (LPO) in mussels. Findings also suggest that at different stages of a toxic bloom, exposure may result in toxic stress to specific organs in the mussel. PMID:16291202

Davies, Warren R; Siu, William H L; Jack, Ralph W; Wu, Rudolf S S; Lam, Paul K S; Nugegoda, Dayanthi

2005-01-01

332

Removal of blue-green algae using the hybrid method of hydrodynamic cavitation and ozonation.  

PubMed

A suspension of Microcystis aeruginosa (30 ?g L(-1)chlorophyll a) was circulated in a hydrodynamic cavitation device and ozone was introduced at the suction side of the pump. The removal of algae over 10 min using hydrodynamic cavitation alone and ozone alone is less than 15% and 35%, respectively. The destruction of algae rises significantly from 24% in the absence of the orifice to 91% with the optimized orifice on 5 min of processing using hydrodynamic cavitation along with ozone (HC/O(3)) and the utilization of ozone increases from 32% to 61%. Interestingly, the suction process is more effective than the extrusion method (positive pressure) and the optimal bulk temperature for algal elimination was found to be 20 °C. Increasing the input concentration of ozone is favorable for the removal of algae but leads to a greater loss of ozone and a decrease in the utilization of ozone. Under the optimal conditions, the algal cells and chlorophyll a are completely destroyed in 10 min by use of the hybrid method. PMID:22883706

Wu, Zhilin; Shen, Haifeng; Ondruschka, Bernd; Zhang, Yongchun; Wang, Weimin; Bremner, David H

2012-10-15

333

A 150 Kilodalton Cell Surface Protein Is Induced by Salt in the Halotolerant Green Alga Dunaliella salina1  

PubMed Central

Dunaliella salina is an extremely halotolerant, unicellular, green alga lacking a rigid cell wall. Osmotic adaptation to high salinities is based on the accumulation of glycerol. To uncover other functions responsible for halotolerance, protein profiles of algae continuously grown in different salinities were compared. A 150 kilodalton protein (p 150) increased in amount with salt concentration. Furthermore, when the cells were subjected to drastic hyperosmotic shocks, p150 started to rise long after completion of the osmotic response but coincident with reinitiation of cell proliferation. Cells with an initially higher level of p150 resumed growth faster than cells with a lower level of the protein. Addition of cycloheximide early after hyperosmotic shock prevented the rise in p150, indicating this rise was due to de novo synthesis of the protein. These observations suggest that p150 is a saltinduced protein required for proliferation of the cells in saline media. p150 was purified to homogeneity and found to be a detergent-soluble glycoprotein. Polyclonal antibodies against p150 recognized a single protein component in D. salina crude extracts. A high Mr cross-reacting protein was also observed in another Dunaliella strain, D. bardawil. Immunoelectron microscopy localized p150 to the cell surface. Images Figure 8 Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 9

Sadka, Avi; Himmelhoch, Stanley; Zamir, Ada

1991-01-01

334

Hydrogen peroxide photoproduction by immobilized cells of the blue-green alga Anabaena variabilis: A way to solar energy conversion  

SciTech Connect

A photosystem for hydrogen peroxide photoproduction formed by immobilized cells of the blue-green alga, Anabaena variabilis and the redox mediator methyl viologen is described. Hydrogen peroxide is produced in a redox catalyst cycle in which methyl viologen is reduced by electrons from water obtained by the photosynthetic apparatus of the algae using solar energy, and reoxidized by the introduction of oxygen into the solution. Hydrogen peroxide is produced during methyl viologen re-oxidation in two steps by means of the formation of superoxide. Experimental conditions for maximum photoproduction (catalyst charge, chlorophyll, and agar final concentration for cell immobilization) have been investigated using a continuous photosystem with immobilized A. variabilis as photocatalyst. Under the determined optimum conditions, the photosystem with immobilized A. variabilis is photocatalyst. Under the determined optimum conditions, the photosystem produces hydrogen peroxide at a rate of 100 {mu}moles/mg Chl{center dot}h, maintaining the production for several hours, and with an energy conversion efficiency of about 2%. Taking into account the use of hydrogen peroxide as fuel, this photosystem can be a useful tool in the storage of solar energy.

Morales, I.; La Rosa, F.F. de (Univ. de Sevilla y CSIC (Spain))

1992-07-01

335

Cytoskeleton mediating transport between the ER system and the Golgi apparatus in the green alga Scenedesmus acutus.  

PubMed

In the green alga Scenedesmus acutus, Golgi bodies are located near the nucleus and supplied with transition vesicles that bud from the outer nuclear envelope membrane. Using this alga, we have shown previously that thiamine pyrophosphatase (TPPase), a marker enzyme of Golgi bodies, migrates in vesicles from the Golgi bodies to the ER via the nuclear envelope in the presence of BFA (Noguchi et al., Protoplasma 201, 202-212, 1998). In this study we demonstrate that both cytochalasin B and oryzalin (microtubule-disrupting agent) inhibit the BFA-induced migration of TPPase from Golgi bodies to the nuclear envelope. However, only actin filaments--not microtubules--can be detected between the nuclear envelope and the Golgi bodies in both BFA-treated and untreated cells. These observations suggest that actin filaments mediate the BFA-induced retrograde transport of vesicles. This mechanism differs from that found in mammalian cells, in which microtubules mediate BFA-induced retrograde transport by the elongation of membrane tubules from the Golgi cisternae. We also discuss the non-participation of the cytoskeleton in anterograde transport from the nuclear envelope to the Golgi bodies. PMID:11089923

Tanaka, Y; Noguchi, T

2000-10-01

336

Characterization and heterologous expression of a new matrix attachment region binding protein from the unicellular green alga Dunaliella salina.  

PubMed

Although interactions between the nuclear matrix and special regions of chromosomal DNA called matrix attachment regions (MARs) are implicated in various nuclear functions, the understanding of the regulatory mechanism of MARs is still poor. A few MAR-binding proteins (MARBP) have been isolated from some plants and animals, but not from the unicellular algae. Here, we identify a novel MAR-binding protein, namely DMBP-1, from the halotolerant alga Dunaliella salina. The cDNA of DMBP-1 is 2322-bp long and contains a 1626 bp of an open reading frame encoding a polypeptide of 542 amino acids (59 kDa). The DMBP-1 expressed in Escherichia coli specifically binds A/T-rich MAR DNA. The DMBP-1 fused to green fluorescent protein appears only inside the nuclei of Chinese hamster ovarian cells transfected with the pEGFP-MBP, indicating that the protein is located in the nuclei. The findings mentioned above may contribute to better understanding of the nuclear matrix-MAR interactions. PMID:20926505

Wang, Tianyun; Hou, Guiqin; Wang, Yafeng; Xue, Lexun

2010-12-01

337

Fresh water blue green algae from three agro-climatic zones of Uttar Pradesh, India: distribution pattern with seasonal variation.  

PubMed

The paper deals with 45 species of 21 genera of fresh water blue green algae (BGA) from three different agro-climatic zones of Uttar Pradesh. Samples were collected from different habitats varying in physico-chemical properties. Out of 45 species, 13 species belonged to order Chroococcales, 31 to order Nostocales, while only 1 species belonged to order Stigonimatales i.e. Fischerella mucicola. The physico-chemical parameters like pH, temperature, dissolved oxygen, electrical conductivity, nitrate, nitrite and rainfall play an important role in the periodicity of BGA. A positive correlation was found between dissolved oxygen (DO) of different ponds and species diversity, except in the case of western region of Uttar Pradesh (Farukhabad and Mahoba districts) where a positive correlation was found in electrical conductivity and total dissolved solids. PMID:16114457

Dwivedi, S; Misra, P K; Rai, U N; Tripathi, R D; Suseela, M R; Sinha, S; Baghel, V S; Pal, Amit; Dwivedi, C P

2005-01-01

338

Identification of carotenoids from green alga Haematococcus pluvialis by HPLC and LC-MS (APCI) and their antioxidant properties.  

PubMed

Haematococcus pluvialis, a green alga accumulates astaxathin upto 2-3% on dry weight basis. In the present study, identification of carotenoids from Haematococcus cyst cell extract by HPLC and LC-MS (APCI) and their antioxidant properties were evaluated in vitro model systems. The extract exhibited 89% and 78% antioxidant activity in beta-carotene linoleate model, and hydroxyl radical scavenging model at 9 ppm of total carotenoid respectively. The extract also showed 80%, 85% and 79% antioxidant activity against lipid peroxidation in kidney, brain and liver of rats. Low-density lipoprotein oxidation induced by Cu2+ ions also protected (45%, 64% and 75%) by the extract in a dose dependent manner with different carotenoid levels. Thiobarbituric acid reactive substances concentration in the blood, liver, and kidney of rat was also significantly (p<0.005) decreased in H. pluvialis treated rats. Potent antioxidant activity is attributable to various carotenoids present in the extract. PMID:19996684

Ranga, Rao; Sarada, A Ravi; Baskaran, V; Ravishankar, G A

2009-11-01

339

ELISA and LC-MS/MS methods for determining cyanobacterial toxins in blue-green algae food supplements.  

PubMed

The use of natural products as a diet supplement is increasing worldwide but sometimes is not followed by adequate sanitary controls and analyses. Twenty samples of pills and capsules of lyophilised cyanobacteria (blue-green algae), commercialised in Italy as dietary supplements, were found positive at the Vibrio fischeri bioassay. Further analyses with ELISA and LC-MS/MS methods revealed the presence of four microcystin (MC) analogues, MC-LR, -YR, -LA, -RR and two demethylated forms of MC-RR. The highest total microcystin content was 4.5 and 1.4 microg g-1 in pills and capsules, respectively. The ELISA measurements, compared to the LC-MS/MS analyses, showed significantly lower concentrations of microcystins in pills, this confirming a possible ELISA underestimate of mixed microcystins, due to different sensitivities for some toxic analogues. PMID:16753920

Bruno, M; Fiori, M; Mattei, D; Melchiorre, S; Messineo, V; Volpi, F; Bogialli, S; Nazzari, M

2006-07-20

340

The sex-inducing pheromone and wounding trigger the same set of genes in the multicellular green alga Volvox.  

PubMed Central

The sex-inducing pheromone of the multicellular green alga Volvox carteri is a glycoprotein that triggers development of males and females at a concentration <10(-16) M. By differential screening of a cDNA library, two novel genes were identified that are transcribed under the control of this pheromone. Unexpectedly, one gene product was characterized as a lysozyme/chitinase, and the other gene product was shown to encode a polypeptide with a striking modular composition. This polypeptide has a cysteine protease domain separated by an extensin-like module from three repeats of a chitin binding domain. In higher plants, similar protein families are known to play an important role in defense against fungi. Indeed, we found that the same set of genes triggered by the sexual pheromone was also inducible in V. carteri by wounding.

Amon, P; Haas, E; Sumper, M

1998-01-01

341

Toxicity of volcanic-ash leachate to a blue-green alga. Results of a preliminary bioassay experiment  

USGS Publications Warehouse

To assess the possible effects of volcanic ash from the May 18,1980, eruption of Mt. St. Helens, Washington, on aquatic ecosystems, we conducted a bioassay experiment with a blue-green alga, Anabaena flos-aquae. Results showed that leachate (obtained by leaching 151 g of ash with 130 mL of simulated freshwater) was lethal to Anabaena flos-aquae cultures when diluted as much as 1:100 with culture medium. Cultures exposed to a 1:500 dilution grew, but a toxic effect was indicated by abnormalities in the Anabaena filaments. This study indicates that ash from the Mt. St. Helens volcano could have an effect on aquatic ecosystems in the areas of significant ashfall. Further study is needed to determine the toxic chemical constituents in the ash and also its possible effects on other aquatic organisms.

McKnight, D. M.; Feder, G. L.; Stiles, E. A.

1981-01-01

342

New lipid-producing, cold-tolerant yellow-green alga isolated from the Rocky Mountains of Colorado.  

PubMed

A new strain of yellow-green algae (Xanthophyceae, Heterokonta), tentatively named Heterococcus sp. DN1 (UTEX accession number UTEX ZZ885), was discovered among snow fields in the Rocky Mountains. Axenic cultures of H. sp. DN1 were isolated and their cellular morphology, growth, and composition of lipids were characterized. H. sp. DN1 was found to grow at temperatures approaching freezing to accumulate large intracellular stores of lipids. H. sp. DN1 produces the highest quantity of lipids when grown undisturbed with high light in low temperatures. Of particular interest was the accumulation of eicosapentaenoic acid, known to be important for human nutrition, and palmitoleic acid, known to improve biodiesel feedstock properties. PMID:23754623

Nelson, David R; Mengistu, Sinafik; Ranum, Paul; Celio, Gail; Mashek, Mara; Mashek, Douglas; Lefebvre, Paul A

2013-01-01

343

Anatoxin-a and its metabolites in blue-green algae food supplements from Canada and Portugal.  

PubMed

Blue-green algae and spirulina are marketed in health food stores and over the Internet as food supplements in Canada, the United States, and Europe. The reported benefits of consuming these products include improved digestion, strengthening of the immune system, and relief from the symptoms of attention deficit disorder. Some of these products have been found to contain elevated concentrations of microcystins, which are known hepatotoxins. In addition to producing microcystins, Anabaena sp. and Aphanizomenon sp. also produce the potent neurotoxin anatoxin-a. Samples of food supplements containing blue-green algae and spirulina were collected in Portugal and from urban centers across Canada in 2005. Extracts of these supplements were analyzed to determine the presence and concentrations of anatoxin-a and its two main metabolites, dihydroanatoxin-a and epoxyanatoxin-a. Initial analyses were performed using high-performance liquid chromatography (HPLC) with fluorescence detection, and confirmation required the use of LC with tandem mass spectrometry (LC-MS-MS). The HPLC with fluorescence detection indicated no anatoxin-a, but four samples were suspected to contain either dihydroanatoxin-a or epoxyanatoxin-a at 0.1 to 0.2 microg/g. LC-MS-MS results, however, indicated no trace of either transformation product in any sample analyzed. The detection limits for anatoxin-a, dihydroanatoxin-a, and epoxyanatoxin-a were similar for both fluorescence detection (0.2 to 0.3, 0.4 to 1.4, and 0.2 to 1.5 pg on the column, respectively) and mass spectrometry (0.3 to 1.5, 0.3 to 0.8, and 0.5 to 0.8 pg on the column, respectively). Because of the higher specificity of the LC-MS-MS analysis, all tested food supplement samples were considered free of anatoxin-a and its transformation products. PMID:17388076

Rawn, Dorothea F K; Niedzwiadek, Barbara; Lau, Benjamin P Y; Saker, Martin

2007-03-01

344

Pectin Metabolism and Assembly in the Cell Wall of the Charophyte Green Alga Penium margaritaceum1[W][OPEN  

PubMed Central

The pectin polymer homogalacturonan (HG) is a major component of land plant cell walls and is especially abundant in the middle lamella. Current models suggest that HG is deposited into the wall as a highly methylesterified polymer, demethylesterified by pectin methylesterase enzymes and cross-linked by calcium ions to form a gel. However, this idea is based largely on indirect evidence and in vitro studies. We took advantage of the wall architecture of the unicellular alga Penium margaritaceum, which forms an elaborate calcium cross-linked HG-rich lattice on its cell surface, to test this model and other aspects of pectin dynamics. Studies of live cells and microscopic imaging of wall domains confirmed that the degree of methylesterification and sufficient levels of calcium are critical for lattice formation in vivo. Pectinase treatments of live cells and immunological studies suggested the presence of another class of pectin polymer, rhamnogalacturonan I, and indicated its colocalization and structural association with HG. Carbohydrate microarray analysis of the walls of P. margaritaceum, Physcomitrella patens, and Arabidopsis (Arabidopsis thaliana) further suggested the conservation of pectin organization and interpolymer associations in the walls of green plants. The individual constituent HG polymers also have a similar size and branched structure to those of embryophytes. The HG-rich lattice of P. margaritaceum, a member of the charophyte green algae, the immediate ancestors of land plants, was shown to be important for cell adhesion. Therefore, the calcium-HG gel at the cell surface may represent an early evolutionary innovation that paved the way for an adhesive middle lamella in multicellular land plants.

Domozych, David S.; S?rensen, Iben; Popper, Zoe A.; Ochs, Julie; Andreas, Amanda; Fangel, Jonatan U.; Pielach, Anna; Sacks, Carly; Brechka, Hannah; Ruisi-Besares, Pia; Willats, William G.T.; Rose, Jocelyn K.C.

2014-01-01

345

Chaperonin Cofactors, Cpn10 and Cpn20, of Green Algae and Plants Function as Hetero-oligomeric Ring Complexes*?  

PubMed Central

The chloroplast chaperonin system of plants and green algae is a curiosity as both the chaperonin cage and its lid are encoded by multiple genes, in contrast to the single genes encoding the two components of the bacterial and mitochondrial systems. In the green alga Chlamydomonas reinhardtii (Cr), three genes encode chaperonin cofactors, with cpn10 encoding a single ?10-kDa domain and cpn20 and cpn23 encoding tandem cpn10 domains. Here, we characterized the functional interaction of these proteins with the Escherichia coli chaperonin, GroEL, which normally cooperates with GroES, a heptamer of ?10-kDa subunits. The C. reinhardtii cofactor proteins alone were all unable to assist GroEL-mediated refolding of bacterial ribulose-bisphosphate carboxylase/oxygenase but gained this ability when CrCpn20 and/or CrCpn23 was combined with CrCpn10. Native mass spectrometry indicated the formation of hetero-oligomeric species, consisting of seven ?10-kDa domains. The cofactor “heptamers” interacted with GroEL and encapsulated substrate protein in a nucleotide-dependent manner. Different hetero-oligomer arrangements, generated by constructing cofactor concatamers, indicated a preferential heptamer configuration for the functional CrCpn10-CrCpn23 complex. Formation of heptamer Cpn10/Cpn20 hetero-oligomers was also observed with the Arabidopsis thaliana (At) cofactors, which functioned with the chloroplast chaperonin, AtCpn60?7?7. It appears that hetero-oligomer formation occurs more generally for chloroplast chaperonin cofactors, perhaps adapting the chaperonin system for the folding of specific client proteins.

Tsai, Yi-Chin C.; Mueller-Cajar, Oliver; Saschenbrecker, Sandra; Hartl, F. Ulrich; Hayer-Hartl, Manajit

2012-01-01

346

Interactive effect of brassinosteroids and cytokinins on growth, chlorophyll, monosaccharide and protein content in the green alga Chlorella vulgaris (Trebouxiophyceae).  

PubMed

Interaction between brassinosteroids (BRs) (brassinolide, BL; 24-epibrassinolide, 24-epiBL; 28-homobrassinolide, 28-homoBL; castasterone, CS; 24-epicastasterone, 24-epiCS; 28-homocastasterone, 28-homoCS) and adenine- (trans-zeatin, tZ; kinetin, Kin) as well as phenylurea-type (1,3-diphenylurea, DPU) cytokinins (CKs) in the regulation of cell number, phytohormone level and the content of chlorophyll, monosaccharide and protein in unicellular green alga Chlorella vulgaris (Trebouxiophyceae) were examined. Chlorella vulgaris exhibited sensitivity to CKs in the following order of their stimulating properties: 10 nM tZ > 100 nM Kin >1 ?M DPU. Exogenously applied BRs possessed the highest biological activity in algal cells at concentration of 10 nM. Among the BRs, BL was characterized by the highest activity, while 28-homoCS - by the lowest. The considerable increase in the level of all endogenous BRs by 27-46% was observed in C. vulgaris culture treated with exogenous 10 nM tZ. It can be speculated that CKs may stimulate BR activity in C. vulgaris by inducing the accumulation of endogenous BRs. CKs interacted synergistically with BRs increasing the number of cells and endogenous accumulation of proteins, chlorophylls and monosaccharides in C. vulgaris. The highest stimulation of algal growth and the contents of analyzed biochemical parameters were observed for BL applied in combination with tZ, whereas the lowest in the culture treated with both 28-homoCS and DPU. However, regardless of the applied mixture of BRs with CKs, the considerable increase in cell number and the metabolite accumulation was found above the level obtained in cultures treated with any single phytohormone in unicellular green alga C. vulgaris. PMID:24787502

Bajguz, Andrzej; Piotrowska-Niczyporuk, Alicja

2014-07-01

347

Enantioselective ecotoxicity of the herbicide dichlorprop and complexes formed with chitosan in two fresh water green algae.  

PubMed

To reduce the leaching potential, to prevent groundwater contamination and to maintain the efficacy of a pesticide, natural polysaccharides have received increasing attention due to their biocompatibility and useful biological reactivity for controlled release formulations (CRFs) of pesticides. In this paper, the toxicities of the chiral herbicide dichlorprop (DCPP) and its complexes with chitosan molecules (DCPP-CS) and chitosan nanoparticles (DCPP-NP) to two different green algae were determined and compared. The inhibition rates of DCPP, DCPP-CS and DCPP-NP were determined at 24, 48, 72, 96, 120, 144, 168 h, and the results show that (S)-DCPP was more toxic to Chlorella vulgaris than (R)-DCPP, while the (R)-DCPP was more toxic to Scenedesmus obliquus than (S)-DCPP. The study also found that the chiral selectivity of DCPP to Chlorella vulgaris and Scenedesmus obliquus could be changed when DCPP was complexed with chitosan molecules (CS) or chitosan nanoparticles (NP). For Chlorella vulgaris, the order of inhibition was (R)-DCPP-CS > (S)-DCPP-CS and (R)-DCPP-NP > (S)-DCPP-NP; for Scenedesmus obliquus, the order was (S)-DCPP-CS > (R)-DCPP-CS and (S)-DCPP-NP > (R)-DCPP-NP. This phenomenon suggests that the enantioselective behaviors of chiral compounds might shift when interactions with other chiral receptors coexist in different biological environments. Additionally, chitosan molecules and chitosan nanoparticles also showed different toxicities, which could be ascribed to the difference in the physicochemical properties between CS and NP or the differences in the cell walls of the two fresh water green algae. PMID:21298177

Wen, Yuezhong; Chen, Hui; Yuan, Yuli; Xu, Dongmei; Kang, Xiaodong

2011-04-01

348

The Ecology of Diatoms in Hardwater Habitats.  

National Technical Information Service (NTIS)

Diatoms comprise the major group of algae in Iowa waters. Their ecological significance, important in pollution evaluation studies, cannot be fully appreciated without a thorough knowledge of their taxonomy. A scale for abundance rating was used giving at...

J. D. Dodd

1971-01-01

349

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

PubMed

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%). PMID:19093085

Peng, Juan; Xiang, WenZhou; Tang, QuanMing; Sun, Ni; Chen, Feng; Yuan, JianPing

2008-12-01

350

Functional characterization of the plastidic phosphate translocator gene family from the thermo-acidophilic red alga Galdieria sulphuraria reveals specific adaptations of primary carbon partitioning in green plants and red algae.  

PubMed

In chloroplasts of green plants and algae, CO(2) is assimilated into triose-phosphates (TPs); a large part of these TPs is exported to the cytosol by a TP/phosphate translocator (TPT), whereas some is stored in the plastid as starch. Plastidial phosphate translocators have evolved from transport proteins of the host endomembrane system shortly after the origin of chloroplasts by endosymbiosis. The red microalga Galdieria sulphuraria shares three conserved putative orthologous transport proteins with the distantly related seed plants and green algae. However, red algae, in contrast to green plants, store starch in their cytosol, not inside plastids. Hence, due to the lack of a plastidic starch pool, a larger share of recently assimilated CO(2) needs to be exported to the cytosol. We thus hypothesized that red algal transporters have distinct substrate specificity in comparison to their green orthologs. This hypothesis was tested by expression of the red algal genes in yeast (Saccharomyces cerevisiae) and assessment of their substrate specificities and kinetic constants. Indeed, two of the three red algal phosphate translocator candidate orthologs have clearly distinct substrate specificities when compared to their green homologs. GsTPT (for G. sulphuraria TPT) displays very narrow substrate specificity and high affinity; in contrast to green plant TPTs, 3-phosphoglyceric acid is poorly transported and thus not able to serve as a TP/3-phosphoglyceric acid redox shuttle in vivo. Apparently, the specific features of red algal primary carbon metabolism promoted the evolution of a highly efficient export system with high affinities for its substrates. The low-affinity TPT of plants maintains TP levels sufficient for starch biosynthesis inside of chloroplasts, whereas the red algal TPT is optimized for efficient export of TP from the chloroplast. PMID:18799657

Linka, Marc; Jamai, Aziz; Weber, Andreas P M

2008-11-01

351

THE EFFECT OF SPECIFIC POISONS UPON THE PHOTO-REDUCTION WITH HYDROGEN IN GREEN ALGAE.  

PubMed

1. The effect of poisons upon the photoreduction with hydrogen in Scenedesmus and similar algae has been studied. The poisons used were cyanide, hydroxylamine, dinitrophenol, and carbon monoxide, substances known to inhibit more or less specifically certain enzymatic reactions. 2. It was found that quite generally one has to distinguish between the action of poisons upon the photoreduction in the stationary state, once this type of metabolism has been well established in the cells, and their effects on transition phenomena, on the "adaptation" and its reversal, the "turnback" from photoreduction to photosynthesis. 3. Cyanide inhibits photoreduction more strongly than it inhibits photosynthesis in the same algae. It is concluded that the mechanism of oxygen liberation, which is idle in photoreduction, is not very sensitive to cyanide. 4. Hydroxylamine in low concentrations is a powerful inhibitor of photosynthesis but has practically no influence on the rate of photoreduction. Consequently, it is assumed that it acts in photosynthesis mainly by inhibiting the evolution of oxygen. Greater concentrations of hydroxylamine clearly inhibit photoreduction, but diminish the rate to about one-half only. A greater degree of inhibition is obtained only by prolonged incubation. 5. Dinitrophenol was found to inhibit strongly the reduction of carbon dioxide, under aerobic as well as under anaerobic conditions. A stimulating effect of dinitrophenol can be demonstrated only with respiration or fermentation, not with photosynthesis. 6. Carbon monoxide interferes with all phases of the hydrogen metabolism in algae. It is supposed therefore to be a specific inhibitor for the hydrogenase system. 7. The "adaptation" to the hydrogen metabolism, which takes place if the algae are incubated anaerobically in hydrogen for several hours, is inhibited completely by very small amounts of cyanide. The adaptation reaction is more sensitive to cyanide than most of the other metabolic processes in the same cell. Correspondingly cyanide enhances the return to aerobic conditions, the "turnback," which occurs under the influence of light of high intensities. 8. Hydroxylamine, applied aerobically, inhibits the adaptation reaction to about the same degree as it inhibits photosynthesis. Photoreduction proceeds after the adaptation in presence of hydroxylamine only at a fraction of the rate that it would have if the poison were added later. 9. Hydroxylamine in concentrations of 10(-3)M protects the anaerobic metabolism against the return to aerobic photosynthesis which normally occurs under the influence of light of too high intensity. The protection is only relative and the higher the light intensity the more hydroxylamine is needed to keep photoreduction going. Once a "turnback" occurs in presence of much hydroxylamine all photochemical gas exchange comes to an end. PMID:19873338

Gaffron, H

1942-11-20

352

Nuclear matrices and matrix attachment regions from Green alga: Dunaliella salina.  

PubMed

Nuclear DNA of eukaryotic organism attaches to the proteinaceous nuclear matrices via specific matrix attachment regions (MARs). In order to investigate the interactions between chromosomal DNA and nuclear matrices,we isolated the MARs from unicellular alga Dunaliella salina. As the first step,a random MAR library was set up and then the binding affinity of the selected clones to nuclear matrices was tested in this study. Three DNA fragments were found to bind specifically to the nuclear matrices in vitro,of which two were strong binders and all contained known consensus motifs and a hairpin loop structure of MAR. PMID:16459661

Wang, Tian-Yun; Hou, Wei-Hong; Chai, Yu-Rong; Ji, Xiang; Wang, Jian-Min; Xue, Le-Xun

2005-12-01

353

Functional Characterization of the Plastidic Phosphate Translocator Gene Family from the Thermo-Acidophilic Red Alga Galdieria sulphuraria Reveals Specific Adaptations of Primary Carbon Partitioning in Green Plants and Red Algae  

Microsoft Academic Search

In chloroplasts of green plants and algae, CO2 is assimilated into triose-phosphates (TPs); a large part of these TPs is exported to the cytosol by a TP\\/phosphate translocator (TPT), whereas some is stored in the plastid as starch. Plastidial phosphate translocators have evolved from transport proteins of the host endomembrane system shortly after the origin of chloroplasts by endosymbiosis. The

Marc Linka; Aziz Jamai; Andreas P. M. Weber

2008-01-01

354

Comparison of plastid 16S rRNA (rrn16) genes from Helicosporidium spp.: evidence supporting the reclassification of Helicosporidia as green algae (Chlorophyta).  

PubMed

The Helicosporidia are invertebrate pathogens that have recently been identified as non-photosynthetic green algae (Chlorophyta). In order to confirm the algal nature of the genus Helicosporidium, the presence of a retained chloroplast genome in Helicosporidia cells was investigated. Fragments homologous to plastid 16S rRNA (rrn16) genes were amplified successfully from cellular DNA extracted from two different Helicosporidium isolates. The fragment sequences are 1269 and 1266 bp long, are very AT-rich (60.7 %) and are similar to homologous genes sequenced from non-photosynthetic green algae. Maximum-parsimony, maximum-likelihood and neighbour-joining methods were used to infer phylogenetic trees from an rrn16 sequence alignment. All trees depicted the Helicosporidia as sister taxa to the non-photosynthetic, pathogenic alga Prototheca zopfii. Moreover, the trees identified Helicosporidium spp. as members of a clade that included the heterotrophic species Prototheca spp. and the mesotrophic species Chlorella protothecoides. The clade is always strongly supported by bootstrap values, suggesting that all these organisms share a most recent common ancestor. Phylogenetic analyses inferred from plastid 16S rRNA genes confirmed that the Helicosporidia are non-photosynthetic green algae, close relatives of the genus Prototheca (Chlorophyta, Trebouxiophyceae). Such phylogenetic affinities suggest that Helicosporidium spp. are likely to possess Prototheca-like organelles and organelle genomes. PMID:14657099

Tartar, Aurélien; Boucias, Drion G; Becnel, James J; Adams, Byron J

2003-11-01

355

Variability and abundance of the epiphytic bacterial community associated with a green marine Ulvacean alga.  

PubMed

Marine Ulvacean algae are colonized by dense microbial communities predicted to have an important role in the development, defense and metabolic activities of the plant. Here we assess the diversity and seasonal dynamics of the bacterial community of the model alga Ulva australis to identify key groups within this epiphytic community. A total of 48 algal samples of U. australis that were collected as 12 individuals at 3 monthly intervals, were processed by applying denaturing gradient gel electrophoresis (DGGE), and three samples from each season were subjected to catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). CARD-FISH revealed that the epiphytic microbial community was comprised mainly of bacterial cells (90%) and was dominated by the groups Alphaproteobacteria (70%) and Bacteroidetes (13%). A large portion (47%) of sequences from the Alphaproteobacteria fall within the Roseobacter clade throughout the different seasons, and an average relative proportion of 19% was observed using CARD-FISH. DGGE based spatial (between tidal pools) and temporal (between season) comparisons of bacterial community composition demonstrated that variation occurs. Between individuals from both the same and different tidal pools, the variation was highest during winter (30%) and between seasons a 40% variation was observed. The community also includes a sub-population of bacteria that is consistently present. Sequences from excised DGGE bands indicate that members of the Alphaproteobacteria and the Bacteroidetes are part of this stable sub-population, and are likely to have an important role in the function of this marine epiphytic microbial community. PMID:19829319

Tujula, Niina A; Crocetti, Gregory R; Burke, Catherine; Thomas, Torsten; Holmström, Carola; Kjelleberg, Staffan

2010-02-01

356

Seasonal variation of antibacterial activities in the green alga Ulva pertusa Kjellman.  

PubMed

The present study was performed to screen out the extracts of algae and assess the seasonal variation in antimicrobial activity of Ulva pertusa against Gardnerella vaginalis. Seasonal variation in antibacterial activity was observed, with the extracts showing no activity during summer and autumn, and showing antibacterial activity from early winter (December) to middle spring (April). The maximum value of antimicrobial activity (6.5 mm inhibition zone at 5 mg disk(-1)) of U. pertusa against G. vaginalis was observed in April. Otherwise, for both chlorophyll a and b, the highest content (2.87 mg g(-1) and 1.37 mg g(-1)) was observed in March 2009. These results may reflect variation in cellular chemical compositions such as secondary metabolite(s) rather than chlorophyll and biological activities according to season. PMID:24665759

Choi, Jae-Suk; Ha, Yu-Mi; Lee, Bo-Bae; Moon, Hye Eun; Cho, Kwang Keun; Choi, In Soon

2014-03-01

357

Food production and gas exchange system using blue-green alga (Spirulina) for CELSS  

NASA Astrophysics Data System (ADS)

In order to reduce the cultivation area required for the growth of higher plants in space adoption of algae, which have a higher photosynthetic ability, seems very suitable for obtaining oxygen and food as a useful source of high quality protein. The preliminary cultivation experiment for determining optimum cultivation conditions and for obtaining the critical design parameters of the cultivator itself has been conducted. Spirulina was cultivated in the 6-liter medium containing a sodium hydrogen carbonate solution and a cultivation temperature controlled using a thermostat. Generated oxygen gas was separated using a polypropyrene porous hollow fiber membrane module. Through this experiment, oxygen gas (at a concentration of more than 46%) at a rate of 100 ~ 150 ml per minute could be obtained.

Oguchi, Mitsuo; Otsubo, Koji; Nitta, Keiji; Hatayama, Shigeki

358

Fatty acids in green algae cultivated on a pilot-plant scale.  

PubMed

Fatty acids from Chlorella vulgaris, Scenedesmus obliquus var. acutus and from a mixed culture of the two strains, Melnik, were converted to methyl esters, separated by gas chromatography, and identified by means of standards. The spectrum of fatty acids included both saturated and unsaturated acids (with odd and even numbers of carbon atoms) from C12 to C22. Fatty acids C16:0, C18:0 and C20:3 were the major components in all cultures. Pure strains differed from the mixed culture in the production of C18:1, C12:0 and C19:2 acids; the first of these was present in higher amounts in pure cultures only, the latter two being found in the mixed culture. The level of lipids was lower as compared to the literature data and their extractability was affected by the manner of preparation of algae and extraction conditions. PMID:744554

Podojil, M; Lívanský, K; Prokes, B; Wurst, M

1978-01-01

359

Hyaluronan synthesis in virus PBCV-1-infected chlorella-like green algae.  

PubMed

We previously reported that the chlorella virus PBCV-1 genome encodes an authentic, membrane-associated glycosyltransferase, hyaluronan synthase (HAS). Hyaluronan, a linear polysaccharide chain composed of alternating beta1,4-glucuronic acid and beta1, 3-N-acetylglucosamine groups, is present in vertebrates as well as a few pathogenic bacteria. Studies of infected cells show that the transcription of the PBCV-1 has gene begins within 10 min of virus infection and ends at 60-90 min postinfection. The hyaluronan polysaccharide begins to accumulate as hyaluronan-lyase sensitive, hair-like fibers on the outside of the chlorella cell wall by 15-30 min postinfection; by 240 min postinfection, the infected cells are coated with a dense fibrous network. This hyaluronan slightly reduces attachment of a second chlorella virus to the infected algae. An analysis of 41 additional chlorella viruses indicates that many, but not all, produce hyaluronan during infection. PMID:10208916

Graves, M V; Burbank, D E; Roth, R; Heuser, J; DeAngelis, P L; Van Etten, J L

1999-04-25

360

ANNA – Artificial Neural Network model for predicting species abundance and succession of blue-green algae  

Microsoft Academic Search

Predictive potential of deductive and inductivephytoplankton models are compared regarding theirusefulness for forecasting and control of harmfulalgal blooms. While applications of deductive modelsstill seem to be restricted by lack of knowledge, ad hocinductive models sometimes prove to bestraightforward and useful. The inductive neuralnetwork model ANNA is documented by means of anapplication to Lake Kasumigaura, Japan. ANNA wasvalidated for five blue-green

Friedrich Recknagel

1997-01-01

361

Soluble Nitrogenase from Vegetative Cells of the Blue-Green Alga Anabaena cylindrica  

Microsoft Academic Search

REPORTS of nitrogen fixation by blue-green algal species have, in the main, been restricted to members of the orders Nostocales and Stigonematales1. Unless they are grown in the presence of large concentrations of free ammonium ions, all the species produce characteristic types of cells called heterocysts. The correlation between the ability of a species to fix nitrogen and the possession

R. V. Smith; M. C. W. Evans

1970-01-01

362

Salicylhydroxamic Acid (SHAM) Inhibition of the Dissolved Inorganic Carbon Concentrating Process in Unicellular Green Algae 1  

PubMed Central

Rates of photosynthetic O2 evolution, for measuring K0.5(CO2 + HCO3?) at pH 7, upon addition of 50 micromolar HCO3? to air-adapted Chlamydomonas, Dunaliella, or Scenedesmus cells, were inhibited up to 90% by the addition of 1.5 to 4.0 millimolar salicylhydroxamic acid (SHAM) to the aqueous medium. The apparent K1(SHAM) for Chlamydomonas cells was about 2.5 millimolar, but due to low solubility in water effective concentrations would be lower. Salicylhydroxamic acid did not inhibit oxygen evolution or accumulation of bicarbonate by Scenedesmus cells between pH 8 to 11 or by isolated intact chloroplasts from Dunaliella. Thus, salicylhydroxamic acid appears to inhibit CO2 uptake, whereas previous results indicate that vanadate inhibits bicarbonate uptake. These conclusions were confirmed by three test procedures with three air-adapted algae at pH 7. Salicylhydroxamic acid inhibited the cellular accumulation of dissolved inorganic carbon, the rate of photosynthetic O2 evolution dependent on low levels of dissolved inorganic carbon (50 micromolar Na-HCO3), and the rate of 14CO2 fixation with 100 micromolar [14C] HCO3?. Salicylhydroxamic acid inhibition of O2 evolution and 14CO2-fixation was reversed by higher levels of NaHCO3. Thus, salicylhydroxamic acid inhibition was apparently not affecting steps of photosynthesis other than CO2 accumulation. Although salicylhydroxamic acid is an inhibitor of alternative respiration in algae, it is not known whether the two processes are related.

Goyal, Arun; Tolbert, N. Edward

1990-01-01

363

QSAR analysis and specific endpoints for classifying the physiological modes of action of biocides in synchronous green algae.  

PubMed

We propose the use of additional physiological endpoints in the 24h growth inhibition test with synchronous cultures of Scenedesmus vacuolatus for the classification of physiological modes of toxic action of chemicals in green algae. The classification scheme is illustrated on the example of one baseline toxicant (3-nitroaniline) and five biocides (irgarol, diuron, Sea-Nine, tributyltin (TBT) and norflurazon). The well-established endpoint of inhibition of reproduction is used for an analysis of the degree of specificity of toxicity by comparing the experimental data with predictions from a quantitative structure-activity relationship (QSAR) for baseline toxicity (narcosis). For those compounds with a toxic ratio greater than 10, i.e. a 10 times higher effect in reproduction than predicted by baseline toxicity, additionally the physiological endpoints inhibition of photosynthesis, cell division and cell volume growth were experimentally assessed. Depending on the relative sensitivity of the different endpoints the chemicals were classified into five different classes of modes of toxic action using a flow chart that was developed in the present study. The advantage of the novel classification scheme is the simplicity of the experimental approach. For the determination of the inhibition of reproduction, the cell size and numbers are quantified with a particle analyzer. This information can be used to derive also the physiological endpoints of cell volume growth and inhibition of cell division. The only additional measurement is the inhibition of the photosynthesis efficiency, which can be easily performed using the non-invasive saturation pulse method and pulse-modulated chlorophyll fluorometry with the Tox-Y-PAM instrument. This mechanistic approach offers a great future potential in ecotoxicology for the physiological mode of action classification of chemicals in algae, which should be a crucial step considered in the risk assessment of chemicals. PMID:18789546

Neuwoehner, Judith; Junghans, Marion; Koller, Mirjam; Escher, Beate I

2008-10-20

364

Molecular and biochemical analysis of the first ARA6 homologue, a RAB5 GTPase, from green algae  

PubMed Central

RAB5 GTPases are important regulators of endosomal membrane traffic in yeast, plants, and animals. A specific subgroup of this family, the ARA6 group, has been described in land plants including bryophytes, lycophytes, and flowering plants. Here, we report on the isolation of an ARA6 homologue in a green alga. CaARA6 (CaRABF1) from Chara australis, a member of the Characeae that is a close relative of land plants, encodes a polypeptide of 237 aa with a calculated molecular mass of 25.4kDa, which is highly similar to ARA6 members from Arabidopsis thaliana and other land plants and has GTPase activity. When expressed in Nicotiana benthamiana leaf epidermal cells, fluorescently tagged CaARA6 labelled organelles with diameters between 0.2 and 1.2 µm, which co-localized with fluorescently tagged AtARA6 known to be present on multivesicular endosomes. Mutations in the membrane-anchoring and GTP-binding sites altered the localization of CaARA6 comparable to that of A. thaliana ARA6 (RABF1). In characean internodal cells, confocal immunofluorescence and immunogold electron microscopy with antibodies against AtARA6 and CaARA6 revealed ARA6 epitopes not only at multivesicular endosomes but also at the plasma membrane, including convoluted domains (charasomes), and at the trans-Golgi network. Our findings demonstrate that ARA6-like proteins have a more ancient origin than previously thought. They indicate further that ARA6-like proteins could have different functions in spite of the high similarity between characean algae and flowering plants.

Foissner, Ilse

2013-01-01

365

A clade uniting the green algae Mesostigma viride and Chlorokybus atmophyticus represents the deepest branch of the Streptophyta in chloroplast genome-based phylogenies  

PubMed Central

Background The Viridiplantae comprise two major phyla: the Streptophyta, containing the charophycean green algae and all land plants, and the Chlorophyta, containing the remaining green algae. Despite recent progress in unravelling phylogenetic relationships among major green plant lineages, problematic nodes still remain in the green tree of life. One of the major issues concerns the scaly biflagellate Mesostigma viride, which is either regarded as representing the earliest divergence of the Streptophyta or a separate lineage that diverged before the Chlorophyta and Streptophyta. Phylogenies based on chloroplast and mitochondrial genomes support the latter view. Because some green plant lineages are not represented in these phylogenies, sparse taxon sampling has been suspected to yield misleading topologies. Here, we describe the complete chloroplast DNA (cpDNA) sequence of the early-diverging charophycean alga Chlorokybus atmophyticus and present chloroplast genome-based phylogenies with an expanded taxon sampling. Results The 152,254 bp Chlorokybus cpDNA closely resembles its Mesostigma homologue at the gene content and gene order levels. Using various methods of phylogenetic inference, we analyzed amino acid and nucleotide data sets that were derived from 45 protein-coding genes common to the cpDNAs of 37 green algal/land plant taxa and eight non-green algae. Unexpectedly, all best trees recovered a robust clade uniting Chlorokybus and Mesostigma. In protein trees, this clade was sister to all streptophytes and chlorophytes and this placement received moderate support. In contrast, gene trees provided unequivocal support to the notion that the Mesostigma + Chlorokybus clade represents the earliest-diverging branch of the Streptophyta. Independent analyses of structural data (gene content and/or gene order) and of subsets of amino acid data progressively enriched in slow-evolving sites led us to conclude that the latter topology reflects the true organismal relationships. Conclusion In disclosing a sister relationship between the Mesostigmatales and Chlorokybales, our study resolves the long-standing debate about the nature of the unicellular flagellated ancestors of land plants and alters significantly our concepts regarding the evolution of streptophyte algae. Moreover, in predicting a richer chloroplast gene repertoire than previously inferred for the common ancestor of all streptophytes, our study has contributed to a better understanding of chloroplast genome evolution in the Viridiplantae.

Lemieux, Claude; Otis, Christian; Turmel, Monique

2007-01-01

366

Growth responses of blue-green algae to sodium chloride concentration  

Microsoft Academic Search

General characteristics of blue-green algal halotolerance were studied by growth experiments and selected analyses. Variation in NaCl concentration was used to mimic salinity. Marine isolates were more halotolerant (8–10% NaCl) than non-marine isolates (2% NaCl). The Na+ requirement for growth was saturated at 1 mg NaCl\\/l for non-marine isolates and 100mg NaCl\\/l for marine isolates. Intracellular Na+ values were affected

John C. Batterton; C. Baalen

1971-01-01

367

Non-Cellulosic Structural Polysaccharides in Algal Cell Walls. III. Mannan in Siphoneous Green Algae  

Microsoft Academic Search

The cell walls of a number of green seaweeds, all members of the Codiaceae and the Dasycladaceae and including Codium and Acetabularia, are shown to contain beta -1,4-linked mannan as the sole crystalline polysaccharide in the complete absence of cellulose. The X-ray diagram of the native mannan (almost identical with that of the mannan of ivory nut and of other

Eva Frei; R. D. Preston

1968-01-01

368

Radiophotosynthesis of some C-labelled Amino Acids using the Unicellular Green Alga Scenedesmus acutus  

Microsoft Academic Search

Radiophotosynthesis has been carried out using the unicellular green algea Scenedesmus acutus grown, as a substrate for preparing some carbon-14 labelled amino acids. Gaseous CO2, in an air tight photosynthesis chamber or NaHCO3 solution, in an ordinary photosynthesis chamber, were used as radioactive carbon sources. The yields, radiochemical yields and specific activities of the formed radioactive products are reported in

M. F. Barakat; A. N. Farag; M. T. Ragab; M. M. El-Fouly; F. K. El-Baz

1990-01-01

369

Endosymbiotic bacteria associated with the intracellular green algae of Hydra viridis  

Microsoft Academic Search

Gram-negative bacteria 4.5–5.5 ?m in length and 1.2 ?m in diameter are found in gastrodermal cells of three stains of freshwater\\u000a green hydras,Hydra viridis (Ohio and Carolina from North America, Jubilee strain from England). They are motile via single polar flagella. They were\\u000a detected in live animals, Jensen stained material, and electron micrographic sections. Bacteria lose motility quickly upon\\u000a release

Lynn Margulis; Glyne Thorington; Brian Berger; John Stolz

1978-01-01

370

Effect of vanadium on growth, chlorophyll formation and iron metabolism in unicellular green algae.  

PubMed

In the presence of vanadium, growth of Scenedesmus obliquus and Chlorella pyrenoidosa was increased five to sixfold as determined by dry weight, when cultured under autotrophic conditions for 7 days. The stimulation by vanadium decreased with increasing stability towards hydrolysis of the iron(III)-compounds added. Pentavalent vanadium (20 mug V/1 as NH4VO3) was able to overcome completely a limited iron-deficiency in the algae following growth in presence of 1.8 - 10(-5) m ferric chloride. Vanadium did not alter the iron uptake into the algal cells. 90% of offered 48V was taken up by Scenedesmus obliquus during 5 days of growth, and 21% thereof were found in the chloroplast fraction. In presence of vanadium, the chlorophyll formation was stimulated in Scenedesmus obliquus. This stimulation by vanadium was found to be light-dependent but occurred to a certain extent in the dark also. The main porphyrin of the yellow mutant 211-11h/20 of Chlorella vulgaris was identified as protoporphyrin-IX. The formation of this compound was stimulated by vanadium within 10 days up to 83%. The role of vanadium in the biosynthesis of chlorophylls is discussed. PMID:1190955

Meisch, H U; Bielig, H J

1975-09-30

371

A simple, low-cost method for chloroplast transformation of the green alga Chlamydomonas reinhardtii.  

PubMed

The availability of routine techniques for the genetic manipulation of the chloroplast genome of Chlamydomonas reinhardtii has allowed a plethora of reverse-genetic studies of chloroplast biology using this alga as a model organism. These studies range from fundamental investigations of chloroplast gene function and regulation to sophisticated metabolic engineering programs and to the development of the algal chloroplast as a platform for producing high-value recombinant proteins. The established method for delivering transforming DNA into the Chlamydomonas chloroplast involves microparticle bombardment, with the selection of transformant lines most commonly involving the use of antibiotic resistance markers. In this chapter we describe a simpler and cheaper delivery method in which cell/DNA suspensions are agitated with glass beads: a method that is more commonly used for nuclear transformation of Chlamydomonas. Furthermore, we highlight the use of an expression vector (pASapI) that employs an endogenous gene as a selectable marker, thereby avoiding the contentious issue of antibiotic resistance determinants in transgenic lines. PMID:24599870

Economou, Chloe; Wannathong, Thanyanan; Szaub, Joanna; Purton, Saul

2014-01-01

372

Biotransformation of benzo[a]pyrene and other polycyclic aromatic hydrocarbons and heterocyclic analogs by several green algae and other algal species under gold and white light.  

PubMed

This laboratory has shown that the metabolism of benzo[a]pyrene (BaP), a carcinogenic polycyclic aromatic hydrocarbon (PAH), by a freshwater green alga, Selenastrum capricornutum, under gold light proceeds through a dioxygenase pathway with subsequent conjugation and excretion. This study was undertaken to determine: (1) the effects of different light sources on the enzymatic or photochemical processes involved in the biotransformation of BaP over a dose range of 5-1200 mg/l; (2) the phototoxicity of carcinogenic PAHs and mutagenic quinones to a green alga; (3) the ability of other algal systems to metabolize BaP. Cultures were exposed to different doses of BaP for 2 days at 23 degrees C under gold, white or UV-A fluorescent light on a diurnal cycle of 16 h light, 8 h dark. Under gold light, metabolites of BaP produced by Selenastrum capricornutum were the dihydrodiols of which the 11,12-dihydrodiol was the major metabolite. Under white light, at low doses, the major metabolite was the 9,10-dihydrodiol. With increasing dose, the ratio of dihydrodiols to quinones decreased to less than two. With increasing light energy output, from gold to white to UV-A in the PAH absorbing region, BaP quinone production increased. Of other carcinogenic PAHs studied, only 7H-dibenz[c,g]carbazole was as phototoxic as BaP while 7,12-dimethylbenz[a]anthracene, dibenz[a,j]acridine and non-carcinogenic PAHs, anthracene and pyrene, were not phototoxic. The 3,6-quinone of BaP was found to be highly phototoxic while quinones that included menadione, danthron, phenanthrene-quinone and hydroquinone were not. The data suggest that the phototoxicity of BaP is due to photochemical production of quinones; the 3,6-quinone of BaP is phototoxic and is probably the result of the production of short lived cyclic reactive intermediates by the interaction of light with the quinone. Lastly, only the green algae, Selenastrum capricornutum, Scenedesmus acutus and Ankistrodesmus braunii almost completely metabolized BaP to dihydrodiols. The green alga Chlamydomonas reinhardtii, the yellow alga Ochromonas malhamensis, the blue green algae Anabaena flosaquae and euglenoid Euglena gracilis did not metabolize BaP to any extent. The data indicate that algae are important in their ability to degrade PAHs but the degradation is dependent on the dose of light energy emitted and absorbed, the dose of PAHs to which the algae are exposed, the phototoxicity of PAHs and their metabolite(s) and the species and strain of algae involved. All of these factors will be important in assessing the degradation and detoxification pathways of recalcitrant PAHs by algae. PMID:7606812

Warshawsky, D; Cody, T; Radike, M; Reilman, R; Schumann, B; LaDow, K; Schneider, J

1995-07-14

373

In vitro and in vivo safety assessment of edible blue-green algae, Nostoc commune var. sphaeroides Kützing and Spirulina plantensis  

Microsoft Academic Search

Blue-green algae (BGA) have been consumed as food and herbal medicine for centuries. However, safety for their consumption has not been well investigated. This study was undertaken to evaluate in vitro and in vivo toxicity of cultivated Nostoc commune var. sphaeroides Kützing (NO) and Spirulina platensis (SP). Neither NO nor SP contained detectable levels of microcystin (MC)-LA, MC-RR, MC-LW and

Yue Yang; Youngki Park; David A. Cassada; Daniel D. Snow; Douglas G. Rogers; Jiyoung Lee

2011-01-01

374

Effects of solar radiation on photosynthesis, UV-absorbing compounds and enzyme activities of the green alga Dasycladus vermicularis from southern Spain  

Microsoft Academic Search

The effect of different wavebands of solar radiation (photosynthetically active radiation (PAR), ultraviolet A (UV-A) and ultraviolet B (UV-B)) produced by use of cut-off filters on chlorophyll fluorescence of the green alga Dasycladus vermicularis was assessed in summerautumn 1996 at a shallow site in Cabo de Gata-Níjar, southern Spain. Similar experiments were carried out under outdoor conditions at Malaga during

Iván Gómez; Eduardo Pérez-Rodríguez; Benjamín Vińegla; Félix L. Figueroa; Ulf Karsten

1998-01-01

375

Rewetting of drought-resistant blue-green algae: Time course of water uptake and reappearance of respiration, photosynthesis, and nitrogen fixation  

Microsoft Academic Search

The response of the terrestrial blue-green algae Nostoc flagelliforme, Nostoc commune, and Nostoc spec. to water uptake has been investigated after a drought period of approximately 2 years. Rapid half-times of rewetting (0.6, 3.3, and 15.5 min, respectively) are found. The surfaceto-mass ratio of the three species is inversely correlated to the speed of water uptake and loss. The ecological

Siegfried Scherer; Anneliese Ernst; Ting-Wei Chen; Peter BiJger

1984-01-01

376

A laboratory investigation of the filtration and ingestion rates of the tilapia, Oreochromis niloticus , feeding on two species of blue-green algae  

Microsoft Academic Search

Synopsis Quantitative aspects of the filter-feeding of the tilapia,Oreochromis niloticus, on two species of the blue-green algae —Anabaena cylindrica andMicrocystis aeruginosa — were investigated in the laboratory. The ingestion rate of 85 mm SLO. niloticus was best fitted using a linear regression over the range of biovolume concentrations studied (3 × 106 ? 3 × 108 ?m3 ml?1). The ingestion

Mark E. Northcott; Malcolm C. M. Beveridge; Lindsay G. Ross

1991-01-01

377

Vacuolar ion currents in the primitive green alga Eremosphaera viridis : The electrical properties are suggestive of both the Characeae and higher plants  

Microsoft Academic Search

Summary The electrical properties of the vacuolar membrane of the primitive green algaEremosphaera virdis were investigated using the patch-clamp technique. In whole vacuole measurements two types of transport systems with long activation time-constants were identified. The first, showing marked outward rectification, was activated by an increase in the cytosolic calcium concentration. Furthermore, it displayed sensitivity to micromolar concentrations of the

K. W. Linz; K. Köhler

1994-01-01

378

Severe Hepatotoxicity CausedbytheTropical Cyanobacterium (Blue-Green Alga) Cylindrospermopsis raciborskii (Woloszynska) Seenaya andSubbaRajuIsolated fromaDomestic Water Supply Reservoir  

Microsoft Academic Search

raciborskii, atropical blooming species ofcyanobacterium (blue-green alga), wasisolated fromthedomestic water supply reservoir onPalmIsland, acontinental island offthetropical northeast coast ofAustralia. Thisspecies, notpreviously knowntobetoxic, wasshowntobeseverely hepatotoxic formice. The 50%lethal doseat24hafter injection wasfound tobe64± 5mgoffreeze-dried culture perkgofmouse. The principal lesion produced wascentrilobular tomassive hepatocyte necrosis, butvarious degrees ofinjury were also seen inthekidneys, adrenal glands, lungs, andintestine. Thepossible implication ofthis finding inrelation toanincident ofhepatoenteritis

C. RUNNEGAR; ALAN R. B. JACKSON

379

Cadmium and iron-stress-inducible gene expression in the green alga Chlamydomonas reinhardtii : evidence for H43 protein function in iron assimilation  

Microsoft Academic Search

Early transcriptional responses of a cell wall-deficient mutant of the green alga Chlamydomonas reinhardtii to heavy-metal stress have been investigated using the method of mRNA differential display. We have identified, sequenced, and quantified the induction of a number of transcripts that are up-regulated by a brief (2-h) exposure to 25 µm cadmium chloride, including one transcript which is also highly

Peter Rubinelli; Surasak Siripornadulsil; Fei Gao-Rubinelli; Richard T. Sayre

2002-01-01

380

Direct effects of Daphnia-grazing, not infochemicals, mediate a shift towards large inedible colonies of the gelatinous green alga Sphaerocystis schroeteri  

Microsoft Academic Search

The influence of Daphnia galeata×hyalina grazing and of infochemicals released by the daphnids on the colony size and growth rate of the colonial gelatinous green alga Sphaerocystis schroeteri (Chlorococcales) was investigated in laboratory batch experiments run for 96h. High zooplankton grazing pressure was exerted by a final concentration of 100daphnidsL?1 in the Daphnia treatments. Infochemicals were obtained by filtration (0.2?m)

Heike Kampe; Marie König-Rinke; Thomas Petzoldt; Jürgen Benndorf

2007-01-01

381

Biotransformation of benzo[ a]pyrene and other polycyclic aromatic hydrocarbons and heterocyclic analogs by several green algae and other algal species under gold and white light  

Microsoft Academic Search

This laboratory has shown that the metabolism of benzo[a]pyrene (BaP), a carcinogenic polycyclic aromatic hydrocarbon (PAH), by a freshwater green alga, Selenastrum capricornutum, under gold light proceeds through a dioxygenase pathway with subsequent conjugation and excretion. This study was undertaken to determine: (1) the effects of different light sources on the enzymatic or photochemical processes involved in the biotransformation of

David Warshawsky; Terence Cody; Martha Radike; Raymond Reilman; Brenda Schumann; Kathy LaDow; Joanne Schneider

1995-01-01

382

Complete Nucleotide Sequence of the Chloroplast Genome from the Green Alga Chlorella vulgaris: The Existence of Genes Possibly Involved in Chloroplast Division  

Microsoft Academic Search

The complete nucleotide sequence of the chloroplast genome (150,613 bp) from the unicellular green alga Chlorella vulgaris C-27 has been determined. The genome contains no large inverted repeat and has one copy of rRNA gene cluster consisting of 16S, 23S, and 5S rRNA genes. It contains 31 tRNA genes, of which the tRNALeu(GAG) gene has not been found in land

Tatsuya Wakasugi; Toshiyuki Nagai; Meenu Kapoor; Mamoru Sugita; Mari Ito; Shiho Ito; Junko Tsudzuki; Keiko Nakashima; Takahiko Tsudzuki; Yasuhiko Suzuki; Akira Hamada; Tutomu Ohta; Atsushi Inamura; Koichi Yoshinaga; Masahiro Sugiura

1997-01-01

383

Morphological and molecular changes in the unicellular green alga Dunaliella salina grown under supplemental UV-B radiation: cell characteristics and Photosystem II damage and repair properties  

Microsoft Academic Search

The effect of supplemental UV-B radiation during growth in the green alga Dunaliella salina was investigated. At the cellular level, supplemental UV-B radiation induced a doubling of the cell volume, a phenomenon attributed to a slow-down in the rate of cell division. At the thylakoid mebrane level, supplemetal UV-B radiation induced photodamage to the 32 kDa (D1) and 34 kDa

Antonio Masi; Anastasios Melis

1997-01-01

384

Morphology and phylogenetic position of a trebouxiophycean green alga (Chlorophyta) growing on the rubber tree, Hevea brasiliensis, with the description of a new genus and species  

Microsoft Academic Search

A novel unicellular Chlorella-like green alga was isolated from the rubber tree (Hevea brasiliensis). The cultured cells were described by light and electron microscopy. Most adult cells were spherical with a single cup-shaped parietal chloroplast, although a few cells contained 2 to 4 chloroplasts. Chloroplasts contained many small pyrenoids with pyrenoglobuli around the multi-oriented tube-like thylakoids in the pyrenoid matrix.

Jiaming Zhang; Volker A. R. Huss; Xuepiao Sun; Kaijun Chang; Daobiao Pang

2008-01-01

385

The effect of different polychlorinated biphenyls on two aquatic models, the green alga Pseudokirchneriella subcapitata and the haemocytes from the European abalone Haliotis tuberculata.  

PubMed

The present study was conducted to determine the toxicity of different polychlorinated biphenyls (PCBs) on the green algae, Pseudokirchneriella subcapitata and the haemocytes from the European abalone, Haliotis tuberculata. Using the algal growth inhibition test, the green algae median Effective Concentration (EC50) values ranged from 0.34?M for PCB28 to more than 100?M for PCBs 101 and 153. Considering the MTT viability test, the abalone EC50 values ranged from 1.67?M for PCB153 to 89?M for PCB28. Our results in contrast to previous observation in vertebrates did not show significant differences between the dioxin like- and non dioxin like-PCBs toxicities regardless of the model used. However, our results demonstrated that the toxicities of PCBs were species dependent. For example, PCB28 was the most toxic compound for P. subcapitata whereas PCBs 1, 180 and 153 were less toxic for that species. On the contrary, PCB153 was reported as the most toxic for H. tuberculata haemocytes and PCB28 the least toxic. To investigate the mode of action of these compounds, we used an in silico method. Our results suggested that PCBs have a non-specific mode of action (e.g., narcosis) on green algae, and another mode of action, probably more specific than narcosis, was reported for PCBs on the abalone haemocytes. PMID:24630249

Halm-Lemeille, Marie-Pierre; Abbaszadeh Fard, Elham; Latire, Thomas; Ferard, Jean-François; Costil, Katherine; Lebel, Jean-Marc; Bureau, Ronan; Serpentini, Antoine

2014-09-01

386

Transcriptional analysis of cell growth and morphogenesis in the unicellular green alga Micrasterias (Streptophyta), with emphasis on the role of expansin  

PubMed Central

Background Streptophyte green algae share several characteristics of cell growth and cell wall formation with their relatives, the embryophytic land plants. The multilobed cell wall of Micrasterias denticulata that rebuilds symmetrically after cell division and consists of pectin and cellulose, makes this unicellular streptophyte alga an interesting model system to study the molecular controls on cell shape and cell wall formation in green plants. Results Genome-wide transcript expression profiling of synchronously growing cells identified 107 genes of which the expression correlated with the growth phase. Four transcripts showed high similarity to expansins that had not been examined previously in green algae. Phylogenetic analysis suggests that these genes are most closely related to the plant EXPANSIN A family, although their domain organization is very divergent. A GFP-tagged version of the expansin-resembling protein MdEXP2 localized to the cell wall and in Golgi-derived vesicles. Overexpression phenotypes ranged from lobe elongation to loss of growth polarity and planarity. These results indicate that MdEXP2 can alter the cell wall structure and, thus, might have a function related to that of land plant expansins during cell morphogenesis. Conclusions Our study demonstrates the potential of M. denticulata as a unicellular model system, in which cell growth mechanisms have been discovered similar to those in land plants. Additionally, evidence is provided that the evolutionary origins of many cell wall components and regulatory genes in embryophytes precede the colonization of land.

2011-01-01

387

Enhanced Carotenoid Biosynthesis by Oxidative Stress in Acetate-Induced Cyst Cells of a Green Unicellular Alga, Haematococcus pluvialis  

PubMed Central

In a green alga, Haematococcus pluvialis, a morphological change of vegetative cells into cyst cells was rapidly induced by the addition of acetate or acetate plus Fe2+ to the vegetative growth phase. Accompanied by cyst formation, algal astaxanthin formation was more enhanced by the addition of acetate plus Fe2+ than by the addition of acetate alone. Encystment and enhanced carotenoid biosynthesis were inhibited by either actinomycin D or cycloheximide. However, after cyst formation was induced by the addition of acetate alone, carotenoid formation could be enhanced with the subsequent addition of Fe2+ even in the presence of the inhibitors. The Fe2+ -enhanced carotenogenesis was inhibited by potassium iodide, a scavenger for hydroxyl radical, suggesting that hydroxyl radical formed by an iron-catalyzed Fenton reaction may be required for enhanced carotenoid biosynthesis. Moreover, it was demonstrated that four active oxygen species, singlet oxygen, superoxide anion radical, hydrogen peroxide, and peroxy radical, were capable of replacing Fe2+ in its role in the enhanced carotenoid formation in the acetate-induced cyst. From these results, it was concluded that oxidative stress is involved in the posttranslational activation of carotenoid biosynthesis in acetate-induced cyst cells. Images

Kobayashi, Makio; Kakizono, Toshihide; Nagai, Shiro

1993-01-01

388

Influence of the CO2 absorbent monoethanolamine on growth and carbon fixation by the green alga Scenedesmus sp.  

PubMed

The influence of monoethanolamine (MEA) as a CO(2) absorbent on photoautotrophic culture of CO(2)-fixing microalgae was investigated. When 300 ppm MEA (4.92 mM) was added to blank culture medium, the dissolved inorganic carbon and the molar absorption ratio increased to 51.0mg/L and 0.34 mol CO2 = mol MEA, respectively, which was an almost 6-fold increase in CO(2) solubility. When free MEA up to 300 mg/L was added to a green alga Scenedesmus sp. culture that was supplied 5% (v/v) CO(2) at 0.1 vvm, both cell growth rate and final cell density were enhanced compared to when no MEA was added. The cell growth rate reached 288.6 mg/L/d, which was equivalent to 539.6 mg-CO(2)/L/d as a CO(2)-fixation rate and enhancement of about 63.0% compared to not adding MEA. Chlorophyll-a content and nitrate consumption rate increased correspondingly. MEA doses higher than 400mg/L inhibited cell growth, probably due to toxicity of the carbamate intermediate. PMID:22771020

Choi, Wookjin; Kim, Garam; Lee, Kisay

2012-09-01

389

Purification and characterization of putative alkaline [Ni-Fe] hydrogenase from unicellular marine green alga, Tetraselmis kochinensis NCIM 1605.  

PubMed

Hydrogenase enzyme from the unicellular marine green alga Tetraselmis kochinensis NCIM 1605 was purified 467 fold to homogeneity. The molecular weight was estimated to be approximately 89kDa by SDS-PAGE. This enzyme consists of two subunits with molecular masses of approximately 70 and approximately 19kDa. The hydrogenase was found to contain 10g atoms of Fe and 1g of atom of Ni per mole of protein. The specific activity of hydrogen evolution was 50micromol H(2)/mg/h of enzyme using reduced methyl viologen as an electron donor. This hydrogenase enzyme has pI value approximately 9.6 representing its alkaline nature. The absorption spectrum of the hydrogenase enzyme showed an absorption peak at 425nm indicating that the enzyme had iron-sulfur clusters. The total of 16 cysteine residues were found per mole of enzyme under the denaturing condition and 20 cysteine residues in reduced denatured enzyme indicating that it has two disulfide bridges. PMID:17321121

Bhosale, S H; Pant, A; Khan, M I

2009-01-01

390

Basal bodies and associated structures are not required for normal flagellar motion or phototaxis in the green alga Chlorogonium elongatum  

PubMed Central

The interphase flagellar apparatus of the green alga Chlorogonium elongatum resembles that of Chlamydomonas reinhardtii in the possession of microtubular rootlets and striated fibers. However, Chlorogonium, unlike Chlamydomonas, retains functional flagella during cell division. In dividing cells, the basal bodies and associated structures are no longer present at the flagellar bases, but have apparently detached and migrated towards the cell equator before the first mitosis. The transition regions remain with the flagella, which are now attached to a large apical mitochondrion by cross-striated filamentous components. Both dividing and nondividing cells of Chlorogonium propagate asymmetrical ciliary-type waveforms during forward swimming and symmetrical flagellar-type waveforms during reverse swimming. High- speed cinephotomicrographic analysis indicates that waveforms, beat frequency, and flagellar coordination are similar in both cell types. This indicates that basal bodies, striated fibers, and microtubular rootlets are not required for the initiation of flagellar beat, coordination of the two flagella, or determination of flagellar waveform. Dividing cells display a strong net negative phototaxis comparable to that of nondividing cells; hence, none of these structures are required for the transmission or processing of the signals involved in phototaxis, or for the changes in flagellar beat that lead to phototactic turning. Therefore, all of the machinery directly involved in the control of flagellar motion is contained within the axoneme and/or transition region. The timing of formation and the positioning of the newly formed basal structures in each of the daughter cells suggests that they play a significant role in cellular morphogenesis.

1985-01-01

391

Effect assessment of the herbicide paraquat on a green alga using differential gene expression and biochemical biomarkers.  

PubMed

Effects of the herbicide paraquat were assessed on the green freshwater alga Chlamydomonas reinhardtii using different endpoints of toxicity. Cell concentration and growth rate were monitored, whereas flow cytometry was applied to determine changes in chlorophyll content, viability and presence of reactive oxygen species. Furthermore, a transcriptomics approach using microarray hybridizations was applied to elucidate the mechanisms of toxicity. The results reveal that paraquat concentrations above 0.25 microM induce toxic effects in C. reinhardtii, reflected in a significantly reduced growth rate and cell concentration with a corresponding median effective concentration (EC50) value of 0.26 microM. With increasing paraquat concentrations, an increase in cell volume was registered with a particle counter as well as in the forward scattering signal of flow cytometric measurements, which is a measure of cell size. Flow cytometry, moreover, showed an increase in reactive oxygen species with increasing exposure concentration, corroborating the general knowledge that this herbicide exerts its toxicity through the generation of oxidative stress. At the same time, several genes involved in oxidative stress defense mechanisms, such as L-ascorbate peroxidase, glutaredoxin, and a possible glutathione-S-transferase were differentially expressed, demonstrating the value of microarrays for elucidating possible mechanisms of toxicity. The fact that several genes were differentially expressed at paraquat concentrations that caused no adverse effects on higher levels of biological organization indicates that a transcriptomics approach allows for the detection of early effects, even before they become manifest at higher levels. PMID:20821519

Jamers, An; De Coen, Wim

2010-04-01

392

Photosystem II Reaction Center Damage and Repair in Dunaliella salina (Green Alga) (Analysis under Physiological and Irradiance-Stress Conditions).  

PubMed Central

Mechanistic aspects of the photosystem II (PSII) damage and repair cycle in chloroplasts were investigated. The D1/32-kD reaction center protein of PSII (known as the psbA chloroplast gene product) undergoes a frequent light-dependent damage and turnover in the thylakoid membrane. In the model organism Dunaliella salina (green alga), growth under a limiting intensity of illumination (100 [mu]mol of photons m-2 s-1; low light) entails damage, degradation, and replacement of D1 every about 7 h. Growth under irradiance-stress conditions (2000 [mu]mol of photons m-2 s-1; high light) entails damage to and replacement of D1 about every 20 min. Thus, the rate of damage and repair of PSII appears to be proportional to the light intensity during plant growth. Low-light-grown cells do not possess the capacity for high rates of repair. Upon transfer of low-light-grown cells to high-light conditions, accelerated damage to reaction center proteins is followed by PSII disassembly and aggregation of neighboring reaction center complexes into an insoluble dimer form. The accumulation of inactive PSII centers that still contain the D1 protein suggests that the rate of D1 degradation is the rate-limiting step in the PSII repair cycle. Under irradiance-stress conditions, chloroplasts gradually acquire a greater capacity for repair. The induction of this phenomenon occurs with a half-time of about 24 h.

Kim, J. H.; Nemson, J. A.; Melis, A.

1993-01-01

393

Comparative study of aluminum and copper transport and toxicity in an acid-tolerant freshwater green alga  

SciTech Connect

A comparative study of the transport and toxicity of one nonessential metal (aluminum), and one essential metal (copper), has been performed with the acid-tolerant green alga Chlorella saccarophila. This organism was isolated from a naturally acidified lake and grows well in laboratory cultures at pH 3.0. Our results show that the fast-exchange ions Ca/sup 2 +/, Mg/sup 2 +/, and Na/sup +/ offer some protection against both Al/sup 3 +/ and Cu/sup 2 +/ toxicity whereas K/sup +/ protects against Al/sup 3 +/ toxicity but enhances Cu/sup 2 +/ toxicity. Plasma emission spectroscopy shows that complexation of Al/sup 3 +/ and Fe/sup 3 +/ to cell surfaces is important in preventing toxic cytoplasmic levels of these metals, both in culture media and in acid mine water. The aqueous ion chemistry for toxic metal uptake is simplified considerably in acidic conditions, where competing hydrolysis and precipitation reactions are eliminated. Therefore, simple competitive experiments can be performed quantitatively. 12 references, 7 figures, 1 table.

Folsom, B.R.; Popescu, N.A.; Wood, J.M.

1986-06-01

394

Sustained Photobiological Hydrogen Gas Production upon Reversible Inactivation of Oxygen Evolution in the Green Alga Chlamydomonas reinhardtii1  

PubMed Central

The work describes a novel approach for sustained photobiological production of H2 gas via the reversible hydrogenase pathway in the green alga Chlamydomonas reinhardtii. This single-organism, two-stage H2 production method circumvents the severe O2 sensitivity of the reversible hydrogenase by temporally separating photosynthetic O2 evolution and carbon accumulation (stage 1) from the consumption of cellular metabolites and concomitant H2 production (stage 2). A transition from stage 1 to stage 2 was effected upon S deprivation of the culture, which reversibly inactivated photosystem II (PSII) and O2 evolution. Under these conditions, oxidative respiration by the cells in the light depleted O2 and caused anaerobiosis in the culture, which was necessary and sufficient for the induction of the reversible hydrogenase. Subsequently, sustained cellular H2 gas production was observed in the light but not in the dark. The mechanism of H2 production entailed protein consumption and electron transport from endogenous substrate to the cytochrome b6-f and PSI complexes in the chloroplast thylakoids. Light absorption by PSI was required for H2 evolution, suggesting that photoreduction of ferredoxin is followed by electron donation to the reversible hydrogenase. The latter catalyzes the reduction of protons to molecular H2 in the chloroplast stroma.

Melis, Anastasios; Zhang, Liping; Forestier, Marc; Ghirardi, Maria L.; Seibert, Michael

2000-01-01

395

Natural History of Transposition in the Green Alga Chlamydomonas reinhardtii: Use of the AMT4 Locus as an Experimental System  

PubMed Central

The AMT4 locus of the green alga Chlamydomonas reinhardtii, which we mapped to the long arm of chromosome 8, provides a good experimental system for the study of transposition. Most mutations that confer resistance to the toxic ammonium analog methylammonium are in AMT4 and a high proportion of spontaneous mutations are caused by transposon-related events. Among the 15 such events that we have characterized at the molecular level, 9 were associated with insertions of the retrotransposon TOC1, 2 with a small Gulliver-related transposon, and 1 with the Tcr1 transposon. We found that Tcr1 is apparently a foldback transposon with terminal inverted repeats that are much longer and more complex than previously realized. A duplication of Tcr1 yielded a configuration thought to be important for chromosomal evolution. Other mutations in AMT4 were caused by two mobile elements that have not been described before. The sequence of one, which we propose to call the Bill element, indicates that it probably transposes by way of a DNA intermediate and requires functions that it does not encode. The sequence of the other and bioinformatic analysis indicates that it derives from a miniature retrotransposon or TRIM, which we propose to call MRC1 (miniature retrotransposon of Chlamydomonas).

Kim, Kwang-Seo; Kustu, Sydney; Inwood, William

2006-01-01

396

Macromolecule Metabolism and Photosynthetic Functions in Blue-Green Algae Treated with Virginiamycin, an Inhibitor of Protein Synthesis  

PubMed Central

The M component of virginiamycin inhibited growth of Plectonema boryanum under both photoautotrophic and heterotrophic conditions. Though the S component of this antibiotic had no apparent activity per se, it enhanced the inhibitory action of its partner. Cells incubated with suitable concentrations of either M or M + S stopped growing and lysed. Loss of the colony-forming capacity occurred quickly in the presence of M + S and slowly in the presence of M alone. Virginiamycin M inhibited protein synthesis in autotrophically and heterotrophically growing Plectonema. This effect was very rapid and could be reversed by removing the antibiotic. The S component did not block the incorporation of amino acids into proteins, but prevented the reversibility of the inhibitory effect of M. Virginiamycin M or S did not affect the photosynthetic oxygen development (Hill's reaction) in Plectonema. Moreover, carbon dioxide photoassimilation and formation of chlorophyll were inhibited only after an appreciable lag. Deoxyribonucleic acid synthesis was blocked virtually without delay by virginiamycin M. Since virginiamycin inhibited protein synthesis in a similar fashion in the unicellular Anacystis nidulans, as well as in the filamentous P. boryanum, the mechanism of action of this antibiotic is probably the same in all blue-green algae.

Cocito, C.; Shilo, M.

1974-01-01

397

On the selective adsorption of cations in the cell wall of the green alga Valonia utricularis  

NASA Astrophysics Data System (ADS)

The selective adsorption of the cations Na+, K+, Mg++ and Ca++ by the cell wall of the Mediterranean alga Valonia utricularis (Siphonocladales, Chlorophyceae) from sea water of 40 %. S was investigated by extraction of cell-wall preparations, eluted before in 1.1 mol methanol (adjusted to pH 8) with 0.1 n formic acid in a Soxhlet apparatus. Na+ and K+ were determined by flame photometry, Mg++ and Ca++ by complexometric titration with EDTA. From calculation of the dry weight:fresh weight ratios and the chloride determinations in the eluates, the Donnan free-space fraction of the total cell-wall volume was calculated to about 35 %, and the analytical results of the cation concentrations in the extracts expressed as ?Val cm-3 DFS. This calculation is based on the assumption that the acidic groups of the noncellulosic matrix material, carrying negative charges by dissociation at the reaction of sea water (ph about 8) are responsible for the adsorption of cations by exhibition of a Donnan effect. The results obtained show clearly that besides the divalent cations Mg++ and Ca++, which according to the physico-chemical laws of the Donnan distribution must be relatively accumulated to the second power of the monovalent ones, potassium is also enriched by selective adsorption, and the K+:Na+ ratio increased significantly compared with that in sea water. This seems to indicate that the strength of attraction between the cations and the negative sites is dependent on the radii of the ions and the state of hydration and/or polarisation of the ions and binding sites.

Kesseler, H.

1980-06-01

398

Diatom Paleolimnology Data Cooperative Home Page  

NSDL National Science Digital Library

The Phycology Section of the Patrick Center for Environmental Research, part of Philadelphia's Academy of Natural Science, presents the Diatom Paleolimnology Data Cooperative (DPDC). This database contains information on diatoms and related ecological and paleolimnological data applicable to the study of global climate change. Users have three search options: browse and download stratigraphic and calibration data sets; view individual diatom counts; or search for occurrences of specific taxa in all data sets. The site includes links to algae databases, also from the Academy of Natural Science. Researchers are encouraged to submit diatom core and surface sediment data to the DPDC.

1998-01-01

399

Alkaloids in Marine Algae  

PubMed Central

This paper presents the alkaloids found in green, brown and red marine algae. Algal chemistry has interested many researchers in order to develop new drugs, as algae include compounds with functional groups which are characteristic from this particular source. Among these compounds, alkaloids present special interest because of their pharmacological activities. Alkaloid chemistry has been widely studied in terrestrial plants, but the number of studies in algae is insignificant. In this review, a detailed account of macro algae alkaloids with their structure and pharmacological activities is presented. The alkaloids found in marine algae may be divided into three groups: 1. Phenylethylamine alkaloids, 2. Indole and halogenated indole alkaloids, 3. Other alkaloids.

Guven, Kas?m Cemal; Percot, Aline; Sezik, Ekrem

2010-01-01

400

Development of a new method for genetic transformation of the green alga Chlorella ellipsoidea.  

PubMed

Chlorella ellipsoidea is a single-celled eukaryotic green microalgae with high nutritional value. Its value may be further increased if a simple, reliable and cost-effective transformation method for C. ellipsoidea can be developed. In this paper, we describe a novel transformation method for C. ellipsoidea . This system is based on treatment of C. ellipsoidea cells with cellulolytic enzymes to weaken their cell walls, making them become competent to take up foreign DNA. To demonstrate the usefulness and effectiveness of this method, we treated C. ellipsoidea cells with a cell wall-degrading enzyme, cellulase, followed by transformation with plasmid pSP-Ubi-GUS harbouring both the zeocin resistance gene and the beta-glucuronidase (GUS) reporter gene that serve as selective makers for transformation. Transformants were readily obtained on zeocin selection medium, reaching transformation efficiency of 2.25 × 10(3) transformants/?g of plasmid DNA. PCR analysis has also demonstrated the presence of the GUS reporter gene in the zeocin-resistant transformants. Histochemical assays further showed the expression of the GUS activity in both primary transformants and transformants after long-term growth (10 months) with antibiotic selection on and off. Availability of a simple and efficient transformation system for C. ellipsoidea will accelerate the exploration of this microalga for a broader range of biotechnological applications, including its use as a biologic factory for the production of high-value human therapeutic proteins. PMID:22580920

Liu, Lili; Wang, Yanqi; Zhang, Yichen; Chen, Xiaoying; Zhang, Ping; Ma, Shengwu

2013-06-01

401

Salinicoccus qingdaonensis sp. nov., isolated from coastal seawater during a bloom of green algae.  

PubMed

A novel Gram-stain-positive, white-pigmented, non-motile, non-sporulating, catalase- and oxidase-positive, strictly aerobic coccus, designated strain ZXM223(T), was isolated from a seawater sample collected from the coast of Qingdao, PR China, during a green algal bloom. It grew at pH 6.0-10.5 and 0-25.0% (w/v) NaCl, with optimum growth at pH 8.5 and 3.0% (w/v) NaCl. Growth occurred at 16-42 °C (optimum at 28 °C). The major fatty acids were anteiso-C(15:0) and iso-C(15:0). Menaquinone 6 (MK-6) was the major respiratory quinone. The polar lipids were phosphatidylglycerol, three unidentified phospholipids and two unknown glycolipids. The peptidoglycan type was L-Lys-Gly(5-6.) The genomic DNA G+C content was 43.5 mol%. Phylogenetic analysis of the 16S rRNA gene sequence placed strain ZXM223(T) within the genus Salinicoccus, with sequence similarity of 92.2-97.1% between ZXM223(T) and the type strains of this genus. The closest relatives were Salinicoccus kunmingensis YIM Y15(T), 'S. salitudinis' YIM-C678 and S. alkaliphilus T8(T). The DNA-DNA relatedness between strain ZXM223(T) and S. kunmingensis CGMCC 1.6302(T) and 'S. salitudinis' CGMCC 1.6299 (=YIM-C678) was 37±3 and 30±2%, respectively. The phenotypic, chemotaxonomic and phylogenetic characteristics and low DNA-DNA relatedness support the proposal of a novel species of the genus Salinicoccus, Salinicoccus qingdaonensis sp. nov., with the type strain ZXM223(T) (=LMG 24855(T) =CGMCC 1.8895(T)). PMID:21498663

Qu, Zhe; Li, Zhao; Zhang, Xiuming; Zhang, Xiao-Hua

2012-03-01

402

Natural dissolved organic matter mobilizes Cd but does not affect the Cd uptake by the green algae Pseudokirchneriella subcapitata (Korschikov) in resin buffered solutions.  

PubMed

Natural dissolved organic matter (DOM) can have contrasting effects on metal bioaccumulation in algae because of complexation reactions that reduce free metal ion concentrations and because of DOM adsorption to algal surfaces which promote metal adsorption. This study was set up to reveal the role of different natural DOM samples on cadmium (Cd) uptake by the green algae Pseudokirchneriella subcapitata (Korschikov). Six different DOM samples were collected from natural freshwater systems and isolated by reverse osmosis. In addition, one (13)C enriched DOM sample was isolated from soil to trace DOM adsorption to algae. Algae were exposed to standardized solutions with or without these DOM samples, each exposed at equal DOM concentrations and at equal non-toxic Cd(2+) activity (?4nM) that was buffered with a resin. The DOM increased total dissolved Cd by factors 3-16 due to complexation reactions at equal Cd(2+) activity. In contrast, the Cd uptake was unaffected by DOM or increased maximally 1.6 fold ((13)C enriched DOM). The (13)C analysis revealed that maximally 6% of algal C was derived from DOM and that this can explain the small increase in biomass Cd. It is concluded that free Cd(2+) and not DOM-complexed Cd is the main bioavailable form of Cd when solution Cd(2+) is well buffered. PMID:24874007

Verheyen, Liesbeth; Versieren, Liske; Smolders, Erik

2014-09-01

403

Acclimation of Photosynthetic Light Reactions during Induction of Inorganic Carbon Accumulation in the Green Alga Chlamydomonas reinhardtii12  

PubMed Central

Cells of the unicellular green algae Chlamydomonas reinhardtii were grown in high dissolved inorganic carbon (DIC) concentrations (supplied with 50 milliliters per liter CO2[g]) and transferred to low DIC concentrations (supplied with ? 100 microliters per liter CO2[g]). Immediately after transfer from high to low DIC the emission of photosystem II related chlorophyll a fluorescence was substantially quenched. It is hypothesized that the suddenly induced inorganic carbon limitation of photosynthesis resulted in a phosphorylation of LHCII, leading to the subsequent state 1 to state 2 transition. After 2 hours of low-DIC acclimation, 77 K fluorescence measurements revealed an increase in the fluorescence emitted from photosystem I, due to direct excitation, suggesting a change in photosystem II/photosystem I stoichiometry or an increased light harvesting capacity of photosystem I. After 5 to 6 hours of acclimation a considerable increase in spillover from photosystem II to photosystem I was observed. These adjustments of the photosynthetic light reactions reached steady-state after about 12 hours of low DIC treatment. The quencher of fluorescence could be removed by 5 minutes of dark treatment followed by 5 minutes of weak light treatment, of any of four different light qualities. It is hypothesized that this restoration of fluorescence was due to a state 2 to state 1 transition in low-DIC acclimated cells. A decreased ratio of violaxanthin to zeaxanthin was also observed in 12 hour low DIC treated cells, compared with high DIC grown cells. This ratio was not coupled to the level of fluorescence quenching. The role of different processes during the induction of a DIC accumulating mechanism is discussed.

Palmqvist, Kristin; Sundblad, Lars-Goran; Wingsle, Gunnar; Samuelsson, Goran

1990-01-01

404

Addressing unknown constants and metabolic network behaviors through petascale computing: understanding H2 production in green algae  

NASA Astrophysics Data System (ADS)

The Genomics Revolution has resulted in a massive and growing quantity of whole-genome DNA sequences, which encode the metabolic catalysts necessary for life. However, gene annotations can rarely be complete, and measurement of the kinetic constants associated with the encoded enzymes can not possibly keep pace, necessitating the use of careful modeling to explore plausible network behaviors. Key challenges are (1) quantitatively formulating kinetic laws governing each transformation in a fixed model network; (2) characterizing the stable solution (if any) of the associated ordinary differential equations (ODEs); (3) fitting the latter to metabolomics data as it becomes available; and, (4) optimizing a model output against the possible space of kinetic parameters, with respect to properties such as robustness of network response, or maximum consumption/production. This SciDAC-2 project addresses this large-scale uncertainty in the genome-scale metabolic network of the water-splitting, H2-producing green alga Chlamydomonas reinhardtii. Each metabolic transformation is formulated as an irreversible steady-state process, such that the vast literature on known enzyme mechanisms may be incorporated directly. To start, glycolysis, the tricarboxylic acid cycle, and basic fermentation pathways have been encoded in Systems Biology Markup Language (SBML) with careful annotation and consistency with the KEGG database, yielding a model with 3 compartments, 95 species, 38 reactions, and 109 kinetic constants. To study and optimize such models with a view toward larger models, we have developed a system which takes as input an SBML model, and automatically produces C code that when compiled and executed optimizes the model's kinetic parameters according to test criteria. We describe the system and present numerical results. Further development, including overlaying of a parallel multistart algorithm, will allow optimization of thousands of parameters on high-performance systems ranging from distributed grids to unified petascale architectures.

Chang, Christopher; Alber, David; Graf, Peter; Kim, Kwiseon; Seibert, Michael

2007-07-01

405

Blue Light, a Positive Switch Signal for Nitrate and Nitrite Uptake by the Green Alga Monoraphidium braunii1  

PubMed Central

Blue light was shown to regulate the utilization of oxidized nitrogen sources by green algae, both by activating nitrate reductase and promoting nitrite reductase biosysnthesis (MA Quińones, PJ Aparicio [1990] Inorganic Nitrogen in Plants and Microorganisms, Springer-Verlag, Berlin, pp 171-177; MA Quińones, PJ Aparicio [1990] Photochem Photobiol 51: 681-692). The data reported herein show that, when cells of Monoraphidium braunii at pH 8, containing both active nitrate reductase and nitrite reductase, were sparged with CO2-free air and irradiated with strong background red light, they took up oxidized nitrogen sources only when PAR comprised blue light. The activation of the transport system(s) of either both nitrate and nitrite was very quick and elicited by low irradiance blue light. In fact, blue light appears to act as a switch signal from the environment, since the uptake of these anions immediately ceased when this radiation was turned off. The requirement of blue light for nitrate uptake was independent of the availability of CO2 to cells. However, cells under high CO2 tensions, although they showed an absolute blue light requirement to initially establish the uptake of nitrite, as they gained carbon skeletons to allocate ammonia, gradually increased their nitrite uptake rates in the subsequent red light intervals. Under CO2-free atmosphere, cells irradiated with strong background red light of 660 nanometers only evolved oxygen when they were additionally irradiated with low irradiance blue light and either nitrate or nitrite was present in the media to provide electron acceptors for the photosynthetic reaction.

Aparicio, Pedro J.; Quinones, Miguel A.

1991-01-01

406

Pectin-like carbohydrates in the green alga Micrasterias characterized by cytochemical analysis and energy filtering TEM.  

PubMed

Pectins are the major matrix polysaccharides of plant cell walls and are important for controlling growth, wall porosity and regulation of the ionic environment in plant cells. Pectic epitopes recognized by the monoclonal antibodies JIM5, JIM7 and 2F4 could be localized in the primary wall during development of the green alga Micrasterias. As the degree of pectin esterification determines the calcium-binding capacity and thus the physical properties of the cell wall, chemical and enzymatic in situ de-esterification was performed. This resulted in displacement of epitopes recognized by JIM5, JIM7 and 2F4, respectively, in changes in the intensity of the antibody labelling as visualized in CLSM. In addition, calcium-binding capacities of cell walls and components of the secretory apparatus were determined in transmission electron microscopy by electron energy loss spectroscopy and electron spectroscopic imaging. These analyses revealed that pectic polysaccharides are transported to the cell wall in a de-esterified form. At the primary wall, pectins get methyl-esterified at the inner side, thus allowing flexibility of the wall. At the outer side of the wall they become again de-esterified and bind high amounts of calcium which leads to cell wall stiffening. Mucilage vesicles possess the highest calcium-binding capacity of all structures observed in Micrasterias, indicating that the pectic polysaccharides of mucilage are secreted in a de-esterified, compact form. When mucilage is excreted through the cell wall, it loses its ability to bind calcium. The esterification of pectins involved is obviously required for swelling of mucilage by water uptake, which generates the motive force for orientation of this unicellular organism in respect to light. Incubation of Micrasterias in pectin methylesterase (PME), which de-esterifies pectic polymers in higher plants, resulted in growth inhibition, cell shape malformation and primary wall thickening. A PME-like enzyme could be found in Micrasterias by PME activity assays. PMID:18778418

Eder, M; Lütz-Meindl, U

2008-08-01

407

Colony organization in the green alga Botryococcus braunii (Race B) is specified by a complex extracellular matrix.  

PubMed

Botryococcus braunii is a colonial green alga whose cells associate via a complex extracellular matrix (ECM) and produce prodigious amounts of liquid hydrocarbons that can be readily converted into conventional combustion engine fuels. We used quick-freeze deep-etch electron microscopy and biochemical/histochemical analysis to elucidate many new features of B. braunii cell/colony organization and composition. Intracellular lipid bodies associate with the chloroplast and endoplasmic reticulum (ER) but show no evidence of being secreted. The ER displays striking fenestrations and forms a continuous subcortical system in direct contact with the cell membrane. The ECM has three distinct components. (i) Each cell is surrounded by a fibrous ?-1, 4- and/or ?-1, 3-glucan-containing cell wall. (ii) The intracolonial ECM space is filled with a cross-linked hydrocarbon network permeated with liquid hydrocarbons. (iii) Colonies are enclosed in a retaining wall festooned with a fibrillar sheath dominated by arabinose-galactose polysaccharides, which sequesters ECM liquid hydrocarbons. Each cell apex associates with the retaining wall and contributes to its synthesis. Retaining-wall domains also form "drapes" between cells, with some folding in on themselves and penetrating the hydrocarbon interior of a mother colony, partitioning it into daughter colonies. We propose that retaining-wall components are synthesized in the apical Golgi apparatus, delivered to apical ER fenestrations, and assembled on the surfaces of apical cell walls, where a proteinaceous granular layer apparently participates in fibril morphogenesis. We further propose that hydrocarbons are produced by the nonapical ER, directly delivered to the contiguous cell membrane, and pass across the nonapical cell wall into the hydrocarbon-based ECM. PMID:22941913

Weiss, Taylor L; Roth, Robyn; Goodson, Carrie; Vitha, Stanislav; Black, Ian; Azadi, Parastoo; Rusch, Jannette; Holzenburg, Andreas; Devarenne, Timothy P; Goodenough, Ursula

2012-12-01

408

Partial purification and characterization of a Ca(2+)-dependent protein kinase from the green alga, Dunaliella salina  

NASA Technical Reports Server (NTRS)

A calcium-dependent protein kinase was partially purified and characterized from the green alga Dunaliella salina. The enzyme was activated at free Ca2+ concentrations above 10(-7) molar. and half-maximal activation was at about 3 x 10(-7) molar. The optimum pH for its Ca(2+)-dependent activity was 7.5. The addition of various phospholipids and diolein had no effects on enzyme activity and did not alter the sensitivity of the enzyme toward Ca2+. The enzyme was inhibited by calmodulin antagonists, N-(6-aminohexyl)-1-naphthalene sulfonamide and N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide in a dose-dependent manner while the protein kinase C inhibitor, sphingosine, had little effect on enzyme activity up to 800 micromolar. Immunoassay showed some calmodulin was present in the kinase preparations. However, it is unlikely the kinase was calmodulin regulated, since it still showed stimulation by Ca2+ in gel assays after being electrophoretically separated from calmodulin by two different methods. This gel method of detection of the enzyme indicated that a protein band with an apparent molecular weight of 40,000 showed protein kinase activity at each one of the several steps in the purification procedure. Gel assay analysis also showed that after native gel isoelectric focusing the partially purified kinase preparations had two bands with calcium-dependent activity, at isoelectric points 6.7 and 7.1. By molecular weight, by isoelectric point, and by a comparative immunoassay, the Dunaliella kinase appears to differ from at least some of the calcium-dependent, but calmodulin and phospholipid independent kinases described from higher plants.

Roux, S. J.

1990-01-01

409

Colony Organization in the Green Alga Botryococcus braunii (Race B) Is Specified by a Complex Extracellular Matrix  

PubMed Central

Botryococcus braunii is a colonial green alga whose cells associate via a complex extracellular matrix (ECM) and produce prodigious amounts of liquid hydrocarbons that can be readily converted into conventional combustion engine fuels. We used quick-freeze deep-etch electron microscopy and biochemical/histochemical analysis to elucidate many new features of B. braunii cell/colony organization and composition. Intracellular lipid bodies associate with the chloroplast and endoplasmic reticulum (ER) but show no evidence of being secreted. The ER displays striking fenestrations and forms a continuous subcortical system in direct contact with the cell membrane. The ECM has three distinct components. (i) Each cell is surrounded by a fibrous ?-1, 4- and/or ?-1, 3-glucan-containing cell wall. (ii) The intracolonial ECM space is filled with a cross-linked hydrocarbon network permeated with liquid hydrocarbons. (iii) Colonies are enclosed in a retaining wall festooned with a fibrillar sheath dominated by arabinose-galactose polysaccharides, which sequesters ECM liquid hydrocarbons. Each cell apex associates with the retaining wall and contributes to its synthesis. Retaining-wall domains also form “drapes” between cells, with some folding in on themselves and penetrating the hydrocarbon interior of a mother colony, partitioning it into daughter colonies. We propose that retaining-wall components are synthesized in the apical Golgi apparatus, delivered to apical ER fenestrations, and assembled on the surfaces of apical cell walls, where a proteinaceous granular layer apparently participates in fibril morphogenesis. We further propose that hydrocarbons are produced by the nonapical ER, directly delivered to the contiguous cell membrane, and pass across the nonapical cell wall into the hydrocarbon-based ECM.

Weiss, Taylor L.; Roth, Robyn; Goodson, Carrie; Vitha, Stanislav; Black, Ian; Azadi, Parastoo; Rusch, Jannette; Holzenburg, Andreas

2012-01-01

410

Photosynthetic activity and protein overexpression found in Cr(III)-tolerant cells of the green algae Dictyosphaerium chlorelloides.  

PubMed

Chromium is an important constituent in effluents obtained from chromium plating industries. Due to the highly toxic nature of Cr(VI), attention has been shifted to less hazardous Cr(III) electroplating processes. This study evaluated aquatic toxicity of Cr(III)-containing laboratory samples representative of effluents from chromium electroplating industries, on the photosynthetic activity exhibited by both Cr(III)-sensitive (Dc1M(wt)) and tolerant (Dc1M(Cr(III)R30)) Dictyosphaerium chlorelloides strains. Additionally, selected de novo-determined peptide sequences, obtained from Dc1M(Cr(III)R30), have been analyzed to evidence the possible Cr(III) toxic mechanism involved in the resistance of these cells to high Cr(III) levels in aquatic environments. Dc1M(Cr(III)R30) strain exhibited a gross photosynthetic balance of about five times lower than that exhibited by Dc1M(wt) strain, demonstrating that Dc1M(Cr(III)R30) has a photosynthetic yield significantly lower than Dc1M(wt). SDS-PAGE of Dc1M(Cr(III)R30) samples showed the presence of at least two protein bands (23.05 and 153.46KDa, respectively) absent in wild-type strain samples. Although it has achieved a low coincidence between the lower molecular weight band and a GTPase identified from genome of the green alga Chlamydomonas reinhardtii, none of de novo peptide sequences obtained showed a significant MS-BLAST score, so that further studies will be required. PMID:24556547

Pereira, M; Bartolomé, C M; Sánchez-Fortún, S

2014-08-01

411

Consequences of state transitions on the structural and functional organization of Photosystem I in the green alga Chlamydomonas reinhardtii.  

PubMed

State transitions represent a photoacclimation process that regulates the light-driven photosynthetic reactions in response to changes in light quality/quantity. It balances the excitation between photosystem I (PSI) and II (PSII) by shuttling LHCII, the main light-harvesting complex of green algae and plants, between them. This process is particularly important in Chlamydomonas reinhardtii in which it is suggested to induce a large reorganization in the thylakoid membrane. Phosphorylation has been shown to be necessary for state transitions and the LHCII kinase has been identified. However, the consequences of state transitions on the structural organization and the functionality of the photosystems have not yet been elucidated. This situation is mainly because the purification of the supercomplexes has proved to be particularly difficult, thus preventing structural and functional studies. Here, we have purified and analysed PSI and PSII supercomplexes of C. reinhardtii in states 1 and 2, and have studied them using biochemical, spectroscopic and structural methods. It is shown that PSI in state 2 is able to bind two LHCII trimers that contain all four LHCII types, and one monomer, most likely CP29, in addition to its nine Lhcas. This structure is the largest PSI complex ever observed, having an antenna size of 340 Chls/P700. Moreover, all PSI-bound Lhcs are efficient in transferring energy to PSI. A projection map at 20 Ĺ resolution reveals the structural organization of the complex. Surprisingly, only LHCII type I, II and IV are phosphorylated when associated with PSI, while LHCII type III and CP29 are not, but CP29 is phosphorylated when associated with PSII in state2. PMID:24506306

Drop, Bartlomiej; Yadav K N, Sathish; Boekema, Egbert J; Croce, Roberta

2014-04-01

412

Addressing Unknown Constants and Metabolic Network Behaviors Through Petascale Computing: Understanding H2 Production in Green Algae  

SciTech Connect

The Genomics Revolution has resulted in a massive and growing quantity of whole-genome DNA sequences, which encode the metabolic catalysts necessary for life. However, gene annotations can rarely be complete, and measurement of the kinetic constants associated with the encoded enzymes can not possibly keep pace, necessitating the use of careful modeling to explore plausible network behaviors. Key challenges are (1) quantitatively formulating kinetic laws governing each transformation in a fixed model network; (2) characterizing the stable solution (if any) of the associated ordinary differential equations (ODEs); (3) fitting the latter to metabolomics data as it becomes available; and, (4) optimizing a model output against the possible space of kinetic parameters, with respect to properties such as robustness of network response, or maximum consumption/production. This SciDAC-2 project addresses this large-scale uncertainty in the genome-scale metabolic network of the water-splitting, H{sub 2}-producing green alga Chlamydomonas reinhardtii. Each metabolic transformation is formulated as an irreversible steady-state process, such that the vast literature on known enzyme mechanisms may be incorporated directly. To start, glycolysis, the tricarboxylic acid cycle, and basic fermentation pathways have been encoded in Systems Biology Markup Language (SBML) with careful annotation and consistency with the KEGG database, yielding a model with 3 compartments, 95 species, 38 reactions, and 109 kinetic constants. To study and optimize such models with a view toward larger models, we have developed a system which takes as input an SBML model, and automatically produces C code that when compiled and executed optimizes the model's kinetic parameters according to test criteria. We describe the system and present numerical results. Further development, including overlaying of a parallel multistart algorithm, will allow optimization of thousands of parameters on high-performance systems ranging from distributed grids to unified petascale architectures.

Chang, C.; Alber, D.; Graf, P.; Seibert, M.

2007-01-01

413

[The cholesterol-lowering effect of the unicellular green alga Scenedesmus acutus 276-3a. II. Effect of alga fractions].  

PubMed

In former experiments we found that the extent of experimentally induced hypercholesterolemia in male Sprague-Dawley rats was significantly reduced by incorporation of 20% Scenedesmus powder in the diet. This paper reports on the localization of the activity in Scenedesmus powder following extraction of hydrophilic and lipophilic fractions. The fractions obtained by hot water treatment and chloroform-methanol extraction and the remaining extracted algae were incorporated in the standard diet in amounts corresponding to 20% Scenedesmus powder. In animals fed on the standard diet + 3% cholesterol for 6 weeks, the average concentration of blood plasma cholesterol increased from 2.0 to 3.5 mmol/l. The average cholesterol level in animals receiving the different algae extracts + 3% cholesterol amounted to between 2.1 and 2.9 mmol/l. The hot water extracted algae material held the plasma cholesterol levels in cholesterol-stressed animals at normal values. The content of plasma triglyceride in animals receiving the different fractions was lowered by 35-55% in nearly all groups. In cholesterol-stressed animals the excessive deposition of cholesterol in the liver was reduced by untreated algal powder as well as algal material extracted with water or chloroform/methanol. The decrease in liver cholesterol amounted to 50%. PMID:7443106

Rolle, I; Pabst, W

1980-01-01

414

Response of benthic algae to environmental gradients in an agriculturally dominated landscape  

USGS Publications Warehouse

Benthic algal communities were assessed in an agriculturally dominated landscape in the Central Columbia Plateau, Washington, to determine which environmental variables best explained species distributions, and whether algae species optima models were useful in predicting specific water-quality parameters. Land uses in the study area included forest, range, urban, and agriculture. Most of the streams in this region can be characterized as open-channel systems influenced by intensive dryland (nonirrigated) and irrigated agriculture. Algal communities in forested streams were dominated by blue-green algae, with communities in urban and range streams dominated by diatoms. The predominance of either blue-greens or diatoms in agricultural streams varied greatly depending on the specific site. Canonical correspondence analysis (CCA) indicated a strong gradient effect of several key environmental variables on benthic algal community composition. Conductivity and % agriculture were the dominant explanatory variables when all sites (n = 24) were included in the CCA; water velocity replaced conductivity when the CCA included only agricultural and urban sites. Other significant explanatory variables included dissolved inorganic nitrogen (DIN), orthophosphate (OP), discharge, and precipitation. Regression and calibration models accurately predicted conductivity based on benthic algal communities, with OP having slightly lower predictability. The model for DIN was poor, and therefore may be less useful in this system. Thirty-four algal taxa were identified as potential indicators of conductivity and nutrient conditions, with most indicators being diatoms except for the blue-greens Anabaena sp. and Lyngbya sp.

Munn, M. D.; Black, R. W.; Gruber, S. J.

2002-01-01

415

Sucrose phosphate phosphatase in the green alga Klebsormidium flaccidum (Streptophyta) lacks an extensive C-terminal domain and differs from that of land plants.  

PubMed

Previously, it was reported that like land plants, the green alga Klebsormidium flaccidum (Streptophyta) accumulates sucrose during cold acclimation (Nagao et al. Plant Cell Environ 31:872-885, 2008), suggesting that synthesis of sucrose could enhance the freezing tolerance of this alga. Because sucrose phosphate phosphatase (SPP; EC 3.1.3.24) is a key enzyme in the sucrose synthesis pathway in plants, we analyzed the SPP gene in K. flaccidum (KfSPP, GenBank accession number AB669024) to clarify its role in sucrose accumulation. As determined from its deduced amino acid sequence, KfSPP contains the N-terminal domain that is characteristic of the L-2-haloacid-dehalogenase family of phosphatases/hydrolases (the HAD phosphatase domain). However, it lacks the extensive C-terminal domain found in SPPs of land plants. Database searches revealed that the SPPs in cyanobacteria also lack the C-terminal domain. In addition, the green alga Coccomyxa (Chlorophyta) and K. flaccidum, which are closely related to land plants, have cyanobacterial-type SPPs, while Chlorella (Chlorophyta) has a land plant-type SPP. These results demonstrate that even K. flaccidum (Streptophyta), as a recent ancestor of land plants, has the cyanobacterial-type SPP lacking the C-terminal domain. Because SPP and sucrose phosphate synthase (SPS) catalyze sequential reactions in sucrose synthesis in green plant cells and the lack of the C-terminal domain in KfSPP is predicted to decrease its activity, the interaction between decreased KfSPP activity and SPS activity may alter sucrose synthesis during cold acclimation in K. flaccidum. PMID:22095241

Nagao, Manabu; Uemura, Matsuo

2012-04-01

416

Characterization and optimization of hydrogen production by a salt water blue-green alga Oscillatoria sp. Miami BG 7. II - Use of immobilization for enhancement of hydrogen production  

NASA Technical Reports Server (NTRS)

The technique of cellular immobilization was applied to the process of hydrogen photoproduction of nonheterocystous, filamentous marine blue-green alga, Oscillatoria sp. Miami BG 7. Immobilization with agar significantly improved the rate and longevity of hydrogen production, compared to free cell suspensions. Rates of H2 production in excess of 13 microliters H2 mg dry/wt h were observed and hydrogen production was sustained for three weeks. Immobilization also provided some stabilization to environmental variability and was adaptable to outdoor light conditions. In general, immobilization provides significant advantages for the production and maintenance of hydrogen photoproduction for this strain.

Phlips, E. J.; Mitsui, A.

1986-01-01

417

[Resolution of the structure of the absorption spectrum of blue-green algae by a method of measuring the 2d derivative at -196 degrees C].  

PubMed

By measuring the 2nd derivative at -196 degrees C the thin structure of the absorption spectrum of intact cells, isolated in phycobilisomes and pure pigments of blue-green algae Anabaena variabilis and Aphanizomanon flos-aquae is shown. 8 absorption bands in the region 669--710 nm pertaining to chlorophyll a in different aggregation region were found. Almost the same number of bands were found in the region 550--660 nm. The latter were conditioned by the absorption of allophycocyanin, phycocyanin, and probably by phycoerythrin present in the form of different associates. PMID:111718

Shubin, L M; Bekasova, O D; Evstigneev, V B

1979-01-01

418

Response of freshwater algae to water quality in Qinshan Lake within Taihu Watershed, China  

NASA Astrophysics Data System (ADS)

Although frequent algal blooms in Taihu Lake in China have become major environmental problems and have drawn national and international attention, little is understood about the relationship between algal blooms and water quality. The goal of this study was to assess the growth and species responses of freshwater algae to variation in water quality in Qinshan Lake, located in headwaters of the Taihu watershed. Water samples were collected monthly from ten study sites in the Qinshan Lake and were analyzed for species distribution of freshwater algae and physiochemical parameters such as total nitrogen (TN), NH4+-N, NO3--N, total phosphorus (TP), chemical oxygen demand (COD Mn) and Chl-a. The results showed that average TN was 4.47 mg/L, with 92.2% of values greater than the TN standard set by the Chinese Environmental Protection Agency; average TP was 0.051 mg/L, with 37.9% of values above the TP national standard; and average trophic level index (TLI) was 53, the lower end of eutrophic condition. Average Chl-a concentration was 12.83 mg/m 3. Green algae and diatom far outweighed other freshwater algae and were dominant most time of the year, with the highest relative abundances of 96% and 99%, respectively. Blue-green algae, composed mainly toxic strains like Microcystis sp ., Nostoc sp. and Oscillatoria sp., became most dominant in the summer with the maximum relative abundance of 69%. The blue-green algae sank to the lake bottom to overwinter, and then dinoflagellates became the dominant species in the winter, with highest relative abundance of 89%. Analysis indicated that nutrients, especially control of ammonia and co-varying nutrients were the major restrictive factor of population growth of blue-green algae, suggesting that control in nutrient enrichments is the major preventive measure of algal blooms in Qinshan Lake.

Zhang, Jianying; Ni, Wanmin; Luo, Yang; Jan Stevenson, R.; Qi, Jiaguo

419

Zoosporangia survival, dehiscence and zoospore formation, and motility in the green alga Rhizoclonium hieroglyphicum as affected by different factors.  

PubMed

Urea at 200 ppm (probably serving as a nitrogen source), liquid Bold's basal medium at pH 7.5, temperature of about 22 degrees C and light intensity of about 40 micromol m(-2) s(-1) for 16 h a day induced rapid and/or abundant zoospores formation and zoosporangia dehiscence and favored zoospore liberation, speed and motility time period in the green alga Rhizoclonium hieroglyphicum. However, factors such as water stress (2 and 4 % agarized media, liquid media with 0.2-0.4 mol/L NaCl, 5-60 min blot-dryness of filaments), pH extremes of liquid media (at < or =6.5 and > or =9.5), temperature shock in liquid media (5 and 35 degrees C for > or =5 min), UV exposure (0.96-3.84 kJ/m2), lack of all nutrients from liquid medium (double distilled water), darkness, and presence of "heavy" metals (1-25 ppm Cu, Fe, Zn, Hg, Ni, Co) or organic substances (200-600 ppm captan or DDT, 800 and 1000 ppm 2,4-D, 50 and 400 ppm indole-3-acetic acid (3-IAA), 1000 and 2000 ppm urea, 100 and 200 ppm thiourea) in liquid media decreased and/or delayed at various levels either zoosporangia survival, zoospore formation or zoosporangia dehiscence and/or the rate of zoospore liberation from zoosporangia, zoospore speed and time period of motility in the media or totally inhibited all these processes. 3-IAA at 50 and 400 ppm induced zoosporangial papilla to grow into a tube-like projection of about 30-120 microm in length. Zoosporangial dehiscence rather than zoospore formation or zoosporangia survival, and zoospore motility period rather than zoospore speed are probably more sensitive to various adverse environmental factors. The rate of zoospores liberation from zoosporangium (possibly related directly to some extent on the zoospore number inside) is probably independent of zoospore speed in the medium. PMID:15702544

Gupta, S; Agrawal, S C

2004-01-01

420

Ferric and cupric reductase activities by iron-limited cells of the green alga Chlorella kessleri: quantification via oxygen electrode.  

PubMed

The colorimetric Fe2+ indicators bathophenanthroline disulfonic acid (BPDS) and 3-(2-pyridyl)-5,6-bis(4-phenylsulfonic acid)-1,2,4-triazine (FZ) are routinely used to assay for plasma membrane ferric reductase activity in iron-limited algal cells and also in roots from iron-limited plants. Ferric reductase assays using these colorimetric indicators must take into account the fact that Fe3+ chelators (e.g. ethylenediaminetetraacetic acid) can also in general bind Fe2+ and may therefore compete with the colorimetric Fe2+ indicators, leading to the potential for underestimation of the ferric reduction rate. Conversely, the presence of BPDS or FZ may also facilitate the reduction of Fe3+ chelates, potentially leading to overestimation of ferric reduction rates. Last, both BPDS and FZ have non-negligible affinities for Fe3+ in addition to their well-known affinities for Fe2+; this leads to potential difficulties in ascertaining whether free and/or chelated Fe3+ are potential substrates for the ferric reductase. Similar issues arise when assaying for cupric reductase activity using the colorimetric Cu+ indicator bathocuproinedisulfonic acid (BCDS). In this paper, we describe an oxygen-electrode-based assay (conducted in darkness) for both ferric and cupric reductase activities that does not use colorimetric indicators. Using this assay system, we show that the plasma membrane metal reductase activity of iron-limited cells of the green alga Chlorella kessleri reduced complexed Fe3+ (i.e. Fe3+ chelates) but did not reduce free (non-chelated) Fe3+, and also reduced free Cu2+ to Cu+, but did not reduce Cu2+ that was part of Cu2+ chelates. We suggest that the potential for reduction of free Fe3+ cannot be adequately assayed using colorimetric assays. As well, the BPDS-based assay system consistently yielded similar estimates of ferric reductase activity compared with the O2-electrode-based assays at relatively low Fe3+ concentration, but higher estimates at higher Fe3+ concentrations with chelators other than desferrioxamine mesylate. With respect to cupric reductase activity, the O2 electrode consistently provided much higher estimates; we suggest that this was as a result of Cu2+ chelation by BCDS leading to a large underestimation of the true cupric reduction rate. These results suggest that an O2-electrode-based metal reductase assay system has some specific advantages compared with the traditional colorimetric assay system, including especially the ability to discriminate between the reduction of free metal ions and chelated metal ions. PMID:18251903

Weger, Harold G; Walker, Crystal N; Fink, Michael B

2007-10-01

421

Integration of TiO2 into the diatom Thalassiosira weissflogii during frustule synthesis  

NASA Astrophysics Data System (ADS)

Nature has inspired the design of complex hierarchical structures in the field of material science. Diatoms, unicellular algae with a hallmark intricate siliceous cell wall, have provided such a stimulus. Altering the chemistry of the diatom frustule has been explored to expand on the potential application of diatoms. The ability to modify the diatom in vivo opens the possibility to tailor the diatom to the end application. Herein, we report the chemical modification of the living diatom T. weissflogii using a titania precursor, titanium (IV) bis-(ammonium lactato)-dihydroxide (TiBALDH). Incorporation of Ti into the diatom is achieved via repeated treatment of cultures with non-toxic concentrations of TiBALDH. The characteristic architectural features of the diatom are unaltered following chemical modification. Transformation of the living diatom provides opportunity to confer novel structural, chemical or functional properties upon the diatom. We report on a photocatalytic ability imparted upon the TiBALDH-modified diatom.

Lang, Yvonne; Monte, Francisco Del; Rodriguez, Brian J.; Dockery, Peter; Finn, David P.; Pandit, Abhay

2013-11-01

422

Xenobiotic biotransformation in unicellular green algae. Involvement of cytochrome P450 in the activation and selectivity of the pyridazinone pro-herbicide metflurazon.  

PubMed Central

The N-demethylation of the pyridazinone pro-herbicide metflurazon into norflurazon implies a toxification in photosynthetic organisms. This is confirmed by quantitative structure activity relationships determined for two unicellular green algae, Chlorella sorokiniana and Chlorella fusca; however, the latter is 25 to 80 times more sensitive to metflurazon. This sensitivity is linked to differences in the N-demethylase activity of both algae, as determined by an optimized in vivo biotransformation assay. Apparent K(m) values of the metflurazon-N-demethylase indicate a 10-fold higher affinity for this xenobiotic substrate for Chlorella fusca. Furthermore, algal metflurazon-N-demethylation is characterized by distinct variations in activity, depending on the stage of cell development within the cell cycle. Several well-established inhibitors of cytochrome P450-mediated reactions, including piperonylbutoxide, 1-aminobenzotriazole, 1-phenoxy-3-(1H-1,2,4-triol-1yl)-4-hydroxy-5,5-dimethylhexane++ +, and tetcyclacis, as well as cinnamic acid, a potential endogenous substrate, inhibited the N-demethylation of metflurazon. The results suggest that the N-demethylation of metflurazon by both algae is mediated by a cytochrome P450 monooxygenase. The determination of antigenic cross-reactivity of algal proteins with heterologous polyclonal antibodies originally raised against plant P450s, anti-cinnamic acid 4-hydroxylase (CYP73A1), anti-ethoxycoumarin-O-dealkylase, anti-tulip allene oxidase (CYP74), and an avocado P450 (CYP71A1) or those of bacterial origin, CYP105A1 and CYP105B1, suggests the presence of distinct P450 isoforms in both algae.

Thies, F; Backhaus, T; Bossmann, B; Grimme, L H

1996-01-01

423

Photosynthetic architecture differs in coastal and oceanic diatoms  

Microsoft Academic Search

Diatoms are a key taxon of eukaryotic phytoplankton and a major contributor to global carbon fixation. They are ubiquitous in the marine ecosystem despite marked gradients in environmental properties, such as dissolved iron concentrations, between coastal and oceanic waters. Previous studies have shown that offshore species of diatoms and other eukaryotic algae have evolved lower iron requirements to subsist in

Robert F. Strzepek; Paul J. Harrison

2004-01-01

424

Isolation and endotoxin activities of lipopolysaccharides from cyanobacterial cultures and complex water blooms and comparison with the effects of heterotrophic bacteria and green alga.  

PubMed

Massive cyanobacterial water blooms are serious environmental and health problems worldwide. While some cyanobacterial toxins such as peptide microcystins have been investigated extensively, other toxic components of cyanobacteria (e.g. lipopolysaccharides, LPS) are poorly understood. The present study characterized endotoxin activities of LPS isolated from (i) laboratory cyanobacterial cultures, (ii) cyanobacterial water bloom samples dominated by Microcystis sp., Planktothrix sp., Aphanizomenon sp. and Anabaena sp., (iii) heterotrophic Gram-negative bacteria Escherichia coli, Kluyvera intermedia, Pseudomonas putida and Pseudomonas fluorescens and (iv) green alga Pseudokirchneriella subcapitata. Toxicity results derived with Limulus amebocyte lysate assay (LAL-test) showed that endotoxin activities of LPS from both cyanobacteria and heterotrophic bacteria were comparable and the values were within a similar range (1 x 10(3)-1 x 10(6) Endotoxin Units, EU, per mg of isolated LPS). The highest activities among the cyanobacterial samples were observed in the Aphanizomenon sp. dominated water bloom. The results also suggest generally higher endotoxin activities in complex natural samples than in laboratory cyanobacterial cultures. Further, experiments with the eukaryotic green alga P. subcapitata demonstrated a need for careful purification of the LPS extracts prior to testing with the LAL assay as several contaminants may overestimate endotoxin activities. This study shows relatively high pyrogenicity of LPS from various cyanobacteria. Further research should focus on detailed toxicological and ecotoxicological characterization of LPS in massive cyanobacterial water blooms. PMID:17461433

Bernardová, Katerina; Babica, Pavel; Marsálek, Blahoslav; Bláha, Ludek

2008-01-01

425

Liver failure in a dog following suspected ingestion of blue-green algae (Microcystis spp.): a case report and review of the toxin.  

PubMed

A 2.5 yr old spayed female Weimaraner presented after ingestion of blue-green algae (Microcystis spp.). One day prior to presentation, the patient was swimming at a local lake known to be contaminated with high levels of blue-green algae that was responsible for deaths of several other dogs the same summer. The patient presented 24 hr after exposure with vomiting, inappetence, weakness, and lethargy. Blood work at the time of admission was consistent with acute hepatic failure, characteristic findings of intoxication by Microcystis spp. Diagnosis was suspected by analyzing a water sample from the location where the patient was swimming. Supportive care including fluids, fresh frozen plasma, whole blood, vitamin K, B complex vitamins, S-adenosyl methionine, and Silybum marianum were started. The patient was discharged on supportive medications, and follow-up blood work showed continued improvement. Ingestion is typically fatal for most patients. This is the first canine to be reported in the literature to survive treatment after known exposure. PMID:23861261

Sebbag, Lionel; Smee, Nicole; van der Merwe, Deon; Schmid, Dustin

2013-01-01

426

Oxidation of c-Type Cytochromes by the Membrane-Bound Cytochrome Oxidase (Cytochrome aa3) of Blue-Green Algae 1  

PubMed Central

Respiratory particles containing an aa3-type cytochrome oxidase were prepared from Anacystis nidulans, Synechocystis 6714, Synechococcus lividus, Anabaena variabilis, Nostoc sp. strain MAC, Nostoc muscorum, and Mastigocladus laminosus. Oxidation of c-type cytochromes by membrane preparations of the different blue-green algae was observed using purified cytochromes from horse heart, Candida krusei, tuna, Saccharomyces oviformis, Rhodospirillum rubrum, Rhodospirillum molischianum, Rhodopseudomonas palustris, Rhodocyclus purpureus, Paracoccus denitrificans, Anacystis nidulans, Anabaena variabilis, Euglena gracilis, and Scenedesmus obliquus. Rapid oxidations were consistently observed with the mitochondrial c-type cytochromes (horse heart cytochrome c reacts most rapidly) and with cytochromes c2 from Rhodopseudomonas palustris and Rhodocyclus purpureus; in contrast, the cytochrome c2 from Rhodospirillum rubrum and the plastidic cytochromes from E. gracilis and Scendesmus obliquus were inactive with all membrane preparations. All reactions were inhibited by low concentrations of KCN, NaN3, and CO, and they were activated by Tween 80, thus indicating participation of the terminal oxidase. The results are discussed in view of the spectral similarities between the terminal oxidase of blue-green algae and the mitochondrial aa3-type cytochrome oxidase of plants and other eukaryotes.

Kienzl, Peter F.; Peschek, Gunter A.

1982-01-01

427

Accumulation of 241Am by suspended matter, diatoms and aquatic weeds of the Yenisei River  

Microsoft Academic Search

In this work we experimentally estimated the capacities of the key components of the Yenisei River (Russia): particulate suspended matter (seston), diatom microalgae, and submerged macrophytes for accumulating 241Am from water. In our experiments large particles of seston (>8?m), comparable in size with diatoms, took up most of americium from water. The accumulation of americium by isolated diatom algae (Asterionella

T. A. Zotina; A. Ya. Bolsunovsky; L. G. Bondareva

2010-01-01

428

Review – Interactions between diatoms and stainless steel: focus on biofouling and biocorrosion  

Microsoft Academic Search

There is a considerable body of information regarding bacterially enhanced corrosion, however, this review focuses on diatoms (unicellular algae) whose contribution to biocorrosion is less well studied. The reasons why diatoms have been neglected in studies of biocorrosion in natural waters are discussed and the question whether diatoms should be considered as inert with respect of electrochemical processes is considered.

J. Landoulsi; K. E. Cooksey; V. Dupres

2011-01-01

429

Effect of retorted-oil shale leachate on a blue-green alga (Anabaena flos-aquae)  

SciTech Connect

Oil shale reserves in Piceance Creek and the White River, Colorado, contain retorted-shale piles which may pollute th eground water through leaching. Bioassay experiments were carried out to determine the effects of leachates on algae, particularly ANABAENA FLOSAQUAE and SCENEDESMUS. Tests were done to establish inhibitionary concentrations of the leachates from various sources of spent shale. Retorted-shale leachates had major effects on the algae papulations at a 40% concentration, minor effects at 8%, and no effects at 0.4%. Discrepancies between experimental results and actual retorted-shale piles are dixcussed. (JMT)

McKnight, D.M.; Pereira, W.E.; Rostad, C.E.; Stiles, E.A.

1983-01-01

430

Low energy method of manufacturing high-grade protein using blue-green algae of the genus Spirulina  

SciTech Connect

Algae are well suited to replace many conventional sources of protein because of their efficient use of energy, land, and raw materials. The most promising genus, Spirulina, is compared with conventional protein sources on the bases of energy efficiency, land usage, and production costs.

Leesley, M.E.; Newsom, T.M.; Burleson, J.D.

1981-01-01

431

Study of the mechanism of biosynthesis of non terpenic hydrocarbons in green alga Botryococcus braunii: Synthesis of labelled intermediates.  

National Technical Information Service (NTIS)

In order to demonstrate the mechanism of elongation-decarboxylation in the development of hydrocarbons of the Botryococcus braunii algae, various radioactive substrates with very long chain have been synthetized: C28 ester, C28 beta-cetoester, C28, C30 an...

T. P. Mong-Sin

1985-01-01

432

Phycoerythrin and photosynthesis of the pelagic blue-green alga Trichodesmium thiebautii in the waters of Kuroshio, Japan  

Microsoft Academic Search

The photosynthetic function of phycoerythrin was investigated in the alga Trichodesmium thiebautii from the waters of Kuroshio, Japan. The spectroscopic characteristics of the in vivo and isolated T. thiebautii phycoerythrin pigments are identical, and have 3 absorption bands at 495, 547 and 562 nm. Light at the wavelengths corresponding to each absorption band of phycoerythrin is equally efficient in T.

S. Shimura; Y. Fujita

1975-01-01

433

Differential response of marine diatoms to solvents  

SciTech Connect

Unicellular algae in aquatic ecosystems are subjected to a variety of pollutants from sources such as runoff from agricultural lands and industrial outfalls. Organic solvents are natural components of oil deposits and commonly find their way into surface waters as a result of discharges from refineries, waste oil, disposal, and accidental spills. Organic solvents can make their way into the environment as industrial wastes. Because of their carcinogenic potential, contamination of soil and water by solvents is cause for serious concern. Relatively few reports have been published on the comparative toxicity of solvents towards test organisms, and these dealt primarily with fish and aquatic invertebrates. However, only few data of toxicity effects of solvents on algae have been published. Phytoplankton species vary in their tolerance to trace metals. Diatoms in particular are able to detoxify trace metals by the excretion of organic compounds. A previous study reported that diatoms collected form different sites in the Gulf of Mexico varied in their physiological characteristics. Algae have been considered to be good indicator s of bioactivity of industrial wastes. Unicellular algae vary in their response to a variety of toxicants. Little is known, however, about toxicity of solvents to marine diatoms. The work reported here was done to examine the effect of selected solvents on seven diatom species to determine whether they differed in their responses to these chemicals. 16 refs., 1 fig.

Tadros, M.G.; Phillips, J.; Patel, H.; Pandiripally, V. [Alabama A & M Univ., Huntsville, AL (United States)

1995-06-01

434

Complete nucleotide sequence of the chloroplast genome from the green alga Chlorella vulgaris: the existence of genes possibly involved in chloroplast division.  

PubMed

The complete nucleotide sequence of the chloroplast genome (150,613 bp) from the unicellular green alga Chlorella vulgaris C-27 has been determined. The genome contains no large inverted repeat and has one copy of rRNA gene cluster consisting of 16S, 23S, and 5S rRNA genes. It contains 31 tRNA genes, of which the tRNALeu(GAG) gene has not been found in land plant chloroplast DNAs analyzed so far. Sixty-nine protein genes and eight ORFs conserved with those found in land plant chloroplasts have also been found. The most striking is the existence of two adjacent genes homologous to bacterial genes involved in cell division, minD and minE, which are arranged in the same order in Escherichia coli. This finding suggests that the mechanism of chloroplast division is similar to bacterial division. Other than minD and minE homologues, genes encoding ribosomal proteins L5, L12, L19, and S9 (rpl5, rpl12, rpl19, and rps9); a chlorophyll biosynthesis Mg chelating subunit (chlI); and elongation factor EF-Tu (tufA), which have not been reported from land plant chloroplast DNAs, are present in this genome. However, many of the new chloroplast genes recently found in red and brown algae have not been found in C. vulgaris. Furthermore, this algal species possesses two long ORFs related to ycf1 and ycf2 that are exclusively found in land plants. These observations suggest that C. vulgaris is closer to land plants than to red and brown algae. PMID:9159184

Wakasugi, T; Nagai, T; Kapoor, M; Sugita, M; Ito, M; Ito, S; Tsudzuki, J; Nakashima, K; Tsudzuki, T; Suzuki, Y; Hamada, A; Ohta, T; Inamura, A; Yoshinaga, K; Sugiura, M

1997-05-27

435

Complete nucleotide sequence of the chloroplast genome from the green alga Chlorella vulgaris: The existence of genes possibly involved in chloroplast division  

PubMed Central

The complete nucleotide sequence of the chloroplast genome (150,613 bp) from the unicellular green alga Chlorella vulgaris C-27 has been determined. The genome contains no large inverted repeat and has one copy of rRNA gene cluster consisting of 16S, 23S, and 5S rRNA genes. It contains 31 tRNA genes, of which the tRNALeu(GAG) gene has not been found in land plant chloroplast DNAs analyzed so far. Sixty-nine protein genes and eight ORFs conserved with those found in land plant chloroplasts have also been found. The most striking is the existence of two adjacent genes homologous to bacterial genes involved in cell division, minD and minE, which are arranged in the same order in Escherichia coli. This finding suggests that the mechanism of chloroplast division is similar to bacterial division. Other than minD and minE homologues, genes encoding ribosomal proteins L5, L12, L19, and S9 (rpl5, rpl12, rpl19, and rps9); a chlorophyll biosynthesis Mg chelating subunit (chlI); and elongation factor EF-Tu (tufA), which have not been reported from land plant chloroplast DNAs, are present in this genome. However, many of the new chloroplast genes recently found in red and brown algae have not been found in C. vulgaris. Furthermore, this algal species possesses two long ORFs related to ycf1 and ycf2 that are exclusively found in land plants. These observations suggest that C. vulgaris is closer to land plants than to red and brown algae.

Wakasugi, Tatsuya; Nagai, Toshiyuki; Kapoor, Meenu; Sugita, Mamoru; Ito, Mari; Ito, Shiho; Tsudzuki, Junko; Nakashima, Keiko; Tsudzuki, Takahiko; Suzuki, Yasuhiko; Hamada, Akira; Ohta, Tutomu; Inamura, Atsushi; Yoshinaga, Koichi; Sugiura, Masahiro

1997-01-01

436

Regeneration and maturation of daughter cell walls in the autospore-forming green alga Chlorella vulgaris (Chlorophyta, Trebouxiophyceae)  

Microsoft Academic Search

Cell-wall synthesis in Chlorella vulgaris, an autospore-forming alga, was observed using the cell wall-specific fluorescent dye Fluostain I. The observation suggested two clearly distinguishable stages in cell-wall synthesis: moderate synthesis during the cell-growth process and rapid synthesis at the cell-division stage. We used electron microscopy to examine the structural changes that occurred with growth in the premature daughter cell wall

Maki Yamamoto; Mariko Fujishita; Aiko Hirata; Shigeyuki Kawano

2004-01-01

437

Organophosphorous insecticides as herbicide synergists on the green algae Pseudokirchneriella subcapitata and the aquatic plant Lemna minor.  

PubMed

Models proposed for risk assessment of chemical mixtures assume no interactions between the chemicals. There are, however, studies indicating that some organophosporous insecticides can inhibit the detoxification of other chemicals in plants thereby enhancing their effect. The present study investigates whether interactions between selected organophosporous insecticides and herbicides can take place in the aquatic algae Pseudokirchneriella subcapitata and the aquatic macrophyte Lemna minor. For both species binary mixtures of the organophosphate insecticides: malathion, endosulfan and chlorpyrifos were tested together with the herbicides metsulfuron-methyl, terbutylazine and bentazone. For mixtures with malathion on algae, dose-response surfaces were made and the results tested against the model of concentration addition (CA) and independent action (IA). The Lemna minor tests showed no indication of synergy for any of the combinations, on the contrary, significant antagonism was found for several of the mixtures. The response surface analysis showed antagonism in relation to both concentration addition and independent action for mixtures between malathion and metsulfuron-methyl and terbuthylazine, while the mixtures with bentazone could be explained with CA. The study shows no indications of synergistic interactions between the tested pesticides, confirming the applicability of CA as a reference model predicting mixture effects of pesticides for aquatic plants and algae. PMID:17940868

Munkegaard, Mads; Abbaspoor, Majid; Cedergreen, Nina

2008-01-01

438

Genetic engineering of the green alga Chlorella zofingiensis: a modified norflurazon-resistant phytoene desaturase gene as a dominant selectable marker.  

PubMed

The unicellular green alga Chlorella zofingiensis has been proposed as a promising producer of natural astaxanthin, a commercially important ketocarotenoid. But the genetic toolbox for this alga is not available. In the present study, an efficient transformation system was established for C. zofingiensis. The transformation system utilized a modified norflurazon-resistant phytoene desaturase (PDS-L5