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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.

Wim van Egmond

2010-01-01

2

Blue-green algae Flagellates Rotifers  

E-print Network

Diatoms Blue-green algae Flagellates Rotifers Green algae Calanoids CyclopoidsNative waterflea). Prefers clear open water in lakes and large rivers. Visual feeders, uses sight instead of smell to find

3

The response of diatom central carbon metabolism to nitrogen starvation is different from that of green algae and higher plants.  

PubMed

The availability of nitrogen varies greatly in the ocean and limits primary productivity over large areas. Diatoms, a group of phytoplankton that are responsible for about 20% of global carbon fixation, respond rapidly to influxes of nitrate and are highly successful in upwelling regions. Although recent diatom genome projects have highlighted clues to the success of this group, very little is known about their adaptive response to changing environmental conditions. Here, we compare the proteome of the marine diatom Thalassiosira pseudonana (CCMP 1335) at the onset of nitrogen starvation with that of nitrogen-replete cells using two-dimensional gel electrophoresis. In total, 3,310 protein spots were distinguishable, and we identified 42 proteins increasing and 23 decreasing in abundance (greater than 1.5-fold change; P < 0.005). Proteins involved in the metabolism of nitrogen, amino acids, proteins, and carbohydrates, photosynthesis, and chlorophyll biosynthesis were represented. Comparison of our proteomics data with the transcriptome response of this species under similar growth conditions showed good correlation and provided insight into different levels of response. The T. pseudonana response to nitrogen starvation was also compared with that of the higher plant Arabidopsis (Arabidopsis thaliana), the green alga Chlamydomonas reinhardtii, and the cyanobacterium Prochlorococcus marinus. We have found that the response of diatom carbon metabolism to nitrogen starvation is different from that of other photosynthetic eukaryotes and bears closer resemblance to the response of cyanobacteria. PMID:22065419

Hockin, Nicola Louise; Mock, Thomas; Mulholland, Francis; Kopriva, Stanislav; Malin, Gill

2012-01-01

4

Interaction of CdSe/ZnS quantum dots with the marine diatom Phaeodactylum tricornutum and the green alga Dunaliella tertiolecta: a biophysical approach.  

PubMed

In this study, we investigated the interaction of nanoparticles, such as CdSe/ZnS quantum dots (QDs), with the marine diatom Phaeodactylum tricornutum and the green alga Dunaliella tertiolecta, as biological models in the marine environment. Fluorescence kinetics measurements indicated that 30min after dispersion in seawater QDs lost the 60% of the initial emission intensity, possibly due to the occurrence of aggregation processes. However, the presence of algae seemed to mitigate this effect. By using confocal microscopy, we highlighted the presence of QDs adsorbed on the surface of both algae, but not inside the cells. The toxicity of QDs was evaluated in terms of inhibition of growth rate, oxidative stress, and lipid peroxidation. QDs in the range of 1-2.5nM gradually inhibited the growth rate of P. tricornutum and increased the oxidative stress, as evinced by the increase in lipid peroxidation, reactive oxygen species (ROS) production and activity of two main antioxidant enzymes (superoxide dismutase and catalase). On the contrary, QDs did not inhibit the growth rate of D. tertiolecta, at most a modest stimulation was observed in the range of 0.5-2nM, suggesting a hormetic response. No effect in the parameters indicating oxidative stress was observed in the green alga. In conclusion our results showed that the biological effects were species-specific. PMID:23845201

Morelli, Elisabetta; Salvadori, Elisa; Bizzarri, Ranieri; Cioni, Patrizia; Gabellieri, Edi

2013-12-01

5

Green-Algae  

E-print Network

Chloroplasts evolved through multiple endosymbioses Endosymbiosis has been a fundamental process in evolution, giving rise to cell organelles including chloroplasts (the center for photosynthesis in plants and algae). Primary chloroplasts in green algae and land plants resulted from an ancient endosymbiotic association with photosynthetic bacteria. Subsequent secondary endosymbioses spread chloroplasts of green and red algae across the tree of life (Fig. 1) [1]. Some algae have undergone even more recent, tertiary endosymbioses, while others contain klepto-chloroplasts (temporary chloroplasts acquired from prey) [2]. The algae Dinophysis has klepto-chloroplasts stolen from photosynthetic prey

Jennifer H. Wisecaver

6

The Effect of Naphthalene-Acetic Acid on Biomass Productivity and Chlorophyll Content of Green Algae, Coccolithophore, Diatom, and Cyanobacterium Cultures  

Microsoft Academic Search

The application of biochemical stimulants to enhance biomass and metabolite productivity is being investigated here and may\\u000a be a simpler approach to achieve our goals of higher productivity and lower costs than methods such as genetic modification.\\u000a The research builds on prior work of screening various biochemical stimulants representing different types of plant growth\\u000a regulators with the green alga, Chlorella

Ryan W. Hunt; Senthil Chinnasamy; K. C. Das

2011-01-01

7

Diatoms  

USGS Multimedia Gallery

Diatoms are algae that reflect the biotic condition of streams, lakes and estuaries. Diatoms are important indicator organisms because they are sensitive to natural and human impacts, and monitoring their condition provides information about ecosystem health....

8

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

9

Introduction to the Green Algae  

NSDL National Science Digital Library

This interesting site on "Green Algae" (a paraphyletic group excluding Plantae) is maintained by the University of California's Museum of Paleontology, and is a central resource for algal information with links to associated resources. Four sections make up the heart of the site: Fossil Record, Life History & Ecology, Systematics, and More on Morphology. Additionally, this well-designed site contains many links to illustrated definitions and additional facts.

Speer, Brian R.

10

Diatoms  

USGS Multimedia Gallery

Diatoms are algae that reflect the biotic condition of streams, lakes and estuaries. Diatoms are important indicator organisms because they are sensitive to natural and human impacts, and monitoring their condition provides information about ecosystem health. Diatoms can live in permanently ice-cove...

11

Hierarchical Silica Nanostructures Inspired by Diatom Algae Yield Superior Deformability, Toughness, and Strength  

E-print Network

Hierarchical Silica Nanostructures Inspired by Diatom Algae Yield Superior Deformability, Toughness algae that is mainly composed of amorphous silica, which features a hierarchical structure that ranges in diatom algae as a basis to study a bioinspired nanoporous material implemented in crystalline silica. We

Buehler, Markus J.

12

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

13

Hierarchical and size dependent mechanical properties of silica and silicon nanostructures inspired by diatom algae  

E-print Network

Biology implements fundamental principles that allow for attractive mechanical properties, as observed in biomineralized structures. For example, diatom algae contain nanoporous hierarchical silicified shells that provide ...

García, Andre Phillipé

2010-01-01

14

Diatoms  

USGS Multimedia Gallery

Diatoms are algae that reflect the biotic condition of streams, lakes and estuaries. Diatoms are important indicator organisms because they are sensitive to natural and human impacts, and monitoring their condition provides information about ecosystem health. Shown here is a live cell of Didymosphen...

15

Diatoms  

USGS Multimedia Gallery

Diatoms are algae that reflect the biotic condition of streams, lakes and estuaries. Diatoms are important indicator organisms because they are sensitive to natural and human impacts, and monitoring their condition provides information about ecosystem health. A large, living Pleurosira laevis cell h...

16

Diatoms  

USGS Multimedia Gallery

Diatoms are algae that reflect the biotic condition of streams, lakes and estuaries. Diatoms are important indicator organisms because they are sensitive to natural and human impacts, and monitoring their condition provides information about ecosystem health. A scanning electron micrograph (SEM) sho...

17

autotrophs from diatoms to brown algae... (chlorophylls a + c1 c2 c3)  

E-print Network

­ life cycle · production of naked flagellates without skeleton #12;Dictyocha ­ recent species Dictyocha· autotrophs ­ from diatoms to brown algae... ­ (chlorophylls a + c1 c2 c3) · heterotrophs · nannoplanktonic, coccoid algae · siliceous cell wall composed of oval or three-sided cell wall (similar to diatoms

18

PPR proteins of green algae  

PubMed Central

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

2013-01-01

19

Hydrocarbons in green and blue-green algae  

Microsoft Academic Search

Liquid column chromatography and thin-layer chromatography were used to determine the total content of hydrocarbons and gas\\u000a 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. InC. kessleri cultivated under heterotrophic conditions the content of

T. ?ezanka; J. Zahradník; M. Podojil

1982-01-01

20

Extracellular Products of Blue Green Algae  

Microsoft Academic Search

SUMMARY An examination was made of soluble extracellular materials produced by Anabaena cylindrica and some other species of blue-green algae, to exasmine whether they have any functional importance. Organisms of all the 15 species (representing 10 genera) examined produced extracellular pigment; with at least 10 of these species part of this pigment was not dif- fusible on dialysis, though the

B. A. WHITTON

1965-01-01

21

Intracellular invasion of green algae in a salamander host  

E-print Network

Intracellular invasion of green algae in a salamander host Ryan Kerneya,1 , Eunsoo Kimb , Roger P) and green algae ("Oophila amblystomatis" Lamber ex Printz) has been considered an ectosymbiotic mutu- alism tracts, consistent with oviductal transmission of algae from one salamander generation to the next

22

Heterotrimeric G-proteins in green algae.  

PubMed

Heterotrimeric G-proteins (G-proteins, hereafter) are important signaling components in all eukaryotes. The absence of these proteins in the sequenced genomes of Chlorophycean green algae has raised questions about their evolutionary origin and prevalence in the plant lineage. The existence of G-proteins has often been correlated with the acquisition of embryophytic life-cycle and/or terrestrial habitats of plants which occurred around 450 million years ago. Our discovery of functional G-proteins in Chara braunii, a representative of the Charophycean green algae, establishes the existence of this conserved signaling pathway in the most basal plants and dates it even further back to 1-1.5 billion years ago. We have now identified the sequence homologs of G-proteins in additional algal families and propose that green algae represent a model system for one of the most basal forms of G-protein signaling known to exist to date. Given the possible differences that exist between plant and metazoan G-protein signaling mechanisms, such basal organisms will serve as important resources to trace the evolutionary origin of proposed mechanistic differences between the systems as well as their plant-specific functions. PMID:25764428

Hackenberg, Dieter; Pandey, Sona

2014-04-01

23

Heterotrimeric G-proteins in green algae  

PubMed Central

Heterotrimeric G-proteins (G-proteins, hereafter) are important signaling components in all eukaryotes. The absence of these proteins in the sequenced genomes of Chlorophycean green algae has raised questions about their evolutionary origin and prevalence in the plant lineage. The existence of G-proteins has often been correlated with the acquisition of embryophytic life-cycle and/or terrestrial habitats of plants which occurred around 450 million years ago. Our discovery of functional G-proteins in Chara braunii, a representative of the Charophycean green algae, establishes the existence of this conserved signaling pathway in the most basal plants and dates it even further back to 1–1.5 billion years ago. We have now identified the sequence homologs of G-proteins in additional algal families and propose that green algae represent a model system for one of the most basal forms of G-protein signaling known to exist to date. Given the possible differences that exist between plant and metazoan G-protein signaling mechanisms, such basal organisms will serve as important resources to trace the evolutionary origin of proposed mechanistic differences between the systems as well as their plant-specific functions. PMID:24614119

Hackenberg, Dieter; Pandey, Sona

2014-01-01

24

Acetylene reduction by nitrogen-fixing blue-green algae  

Microsoft Academic Search

Known nitrogen-fixing species of blue-green algae are capable of reducing acetylene to ethylene, but acetylene is not reduced by Anacystis nidulans, which does not fix nitrogen. Cycad root nodules which contain blue-green algae as endophytes reduce acetylene. Acetylene reduction is inhibited by carbon monoxide. Nitrate or ammonium-nitrogen has no immediate effect on algae reducing acetylene, but algae grown on nitrate-nitrogen

W. D. P. Stewart; G. P. Fitzgerald; R. H. Burris

1968-01-01

25

Parachloroidium gen. nov. (Trebouxiophyceae, Chlorophyta), a novel genus of coccoid green algae from subaerial corticolous biofilms  

E-print Network

Parachloroidium gen. nov. (Trebouxiophyceae, Chlorophyta), a novel genus of coccoid green algae. Parachloroidium gen. nov. (Trebouxiophyceae, Chlorophyta), a novel genus of coccoid green algae from subaerial the Parachloroidium strains from other similar green algae. However, ultrastructural characteristics and molecular

26

Blue-Green Algae: Why They Become Dominant  

Microsoft Academic Search

The injection of carbon dioxide and the addition of nitrogen and phosphorus to a lake population dominated by blue-green algae results in a rapid shift to dominance by green algae. The basis for the change and its implications are discussed.

Joseph Shapiro

1973-01-01

27

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

28

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

29

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

30

Green autofluorescence in dinoflagellates, diatoms, and other microalgae and its implications for vital staining and morphological studies.  

PubMed

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. PMID:17277199

Tang, Ying Zhong; Dobbs, Fred C

2007-04-01

31

RESEARCH ARTICLE Open Access Origin of land plants: Do conjugating green algae  

E-print Network

RESEARCH ARTICLE Open Access Origin of land plants: Do conjugating green algae hold the key? Sabina (embryophytes) evolved from streptophyte algae, also referred to as charophycean algae. The streptophyte algae are a paraphyletic group of green algae, ranging from unicellular flagellates to morphologically complex forms

32

Plastid proteome prediction for diatoms and other algae with secondary plastids of the red lineage.  

PubMed

The plastids of ecologically and economically important algae from phyla such as stramenopiles, dinoflagellates and cryptophytes were acquired via a secondary endosymbiosis and are surrounded by three or four membranes. Nuclear-encoded plastid-localized proteins contain N-terminal bipartite targeting peptides with the conserved amino acid sequence motif 'ASAFAP'. Here we identify the plastid proteomes of two diatoms, Thalassiosira pseudonana and Phaeodactylum tricornutum, using a customized prediction tool (ASAFind) that identifies nuclear-encoded plastid proteins in algae with secondary plastids of the red lineage based on the output of SignalP and the identification of conserved 'ASAFAP' motifs and transit peptides. We tested ASAFind against a large reference dataset of diatom proteins with experimentally confirmed subcellular localization and found that the tool accurately identified plastid-localized proteins with both high sensitivity and high specificity. To identify nucleus-encoded plastid proteins of T. pseudonana and P. tricornutum we generated optimized sets of gene models for both whole genomes, to increase the percentage of full-length proteins compared with previous assembly model sets. ASAFind applied to these optimized sets revealed that about 8% of the proteins encoded in their nuclear genomes were predicted to be plastid localized and therefore represent the putative plastid proteomes of these algae. PMID:25438865

Gruber, Ansgar; Rocap, Gabrielle; Kroth, Peter G; Armbrust, E Virginia; Mock, Thomas

2015-02-01

33

Plastid proteome prediction for diatoms and other algae with secondary plastids of the red lineage  

PubMed Central

The plastids of ecologically and economically important algae from phyla such as stramenopiles, dinoflagellates and cryptophytes were acquired via a secondary endosymbiosis and are surrounded by three or four membranes. Nuclear-encoded plastid-localized proteins contain N-terminal bipartite targeting peptides with the conserved amino acid sequence motif ‘ASAFAP’. Here we identify the plastid proteomes of two diatoms, Thalassiosira pseudonana and Phaeodactylum tricornutum, using a customized prediction tool (ASAFind) that identifies nuclear-encoded plastid proteins in algae with secondary plastids of the red lineage based on the output of SignalP and the identification of conserved ‘ASAFAP’ motifs and transit peptides. We tested ASAFind against a large reference dataset of diatom proteins with experimentally confirmed subcellular localization and found that the tool accurately identified plastid-localized proteins with both high sensitivity and high specificity. To identify nucleus-encoded plastid proteins of T. pseudonana and P. tricornutum we generated optimized sets of gene models for both whole genomes, to increase the percentage of full-length proteins compared with previous assembly model sets. ASAFind applied to these optimized sets revealed that about 8% of the proteins encoded in their nuclear genomes were predicted to be plastid localized and therefore represent the putative plastid proteomes of these algae. PMID:25438865

Gruber, Ansgar; Rocap, Gabrielle; Kroth, Peter G; Armbrust, E Virginia; Mock, Thomas

2015-01-01

34

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

35

Photobiological hydrogen production in green algae and photosynthetic bacteria  

SciTech Connect

We have shown that, under appropriate physiological conditions, certain freshwater and marine green algae are capable of splitting water to molecular hydrogen and oxygen in a sustained steady-state reaction. In these algae, the gaseous-fuel-producing reaction can be driven by light throughout the visible portion of the solar emission spectrum, including the long wavelength (red) 700-nm region. No external energy sources are required.

Greenbaum, E.

1986-01-01

36

Carbon Partitioning in Green Algae (Chlorophyta) and the Enolase Enzyme  

PubMed Central

The exact mechanisms underlying the distribution of fixed carbon within photoautotrophic cells, also referred to as carbon partitioning, and the subcellular localization of many enzymes involved in carbon metabolism are still unknown. In contrast to the majority of investigated green algae, higher plants have multiple isoforms of the glycolytic enolase enzyme, which are differentially regulated in higher plants. Here we report on the number of gene copies coding for the enolase in several genomes of species spanning the major classes of green algae. Our genomic analysis of several green algae revealed the presence of only one gene coding for a glycolytic enolase [EC 4.2.1.11]. Our predicted cytosolic localization would require export of organic carbon from the plastid to provide substrate for the enolase and subsequent re-import of organic carbon back into the plastids. Further, our comparative sequence study of the enolase and its 3D-structure prediction may suggest that the N-terminal extension found in green algal enolases could be involved in regulation of the enolase activity. In summary, we propose that the enolase represents one of the crucial regulatory bottlenecks in carbon partitioning in green algae. PMID:25093929

Polle, Jürgen E. W.; Neofotis, Peter; Huang, Andy; Chang, William; Sury, Kiran; Wiech, Eliza M.

2014-01-01

37

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

38

Development of Green Fuels From Algae - The University of Tulsa  

SciTech Connect

The general public has become increasingly aware of the pitfalls encountered with the continued reliance on fossil fuels in the industrialized world. In response, the scientific community is in the process of developing non-fossil fuel technologies that can supply adequate energy while also being environmentally friendly. In this project, we concentrate on â??green fuelsâ?ť which we define as those capable of being produced from renewable and sustainable resources in a way that is compatible with the current transportation fuel infrastructure. One route to green fuels that has received relatively little attention begins with algae as a feedstock. Algae are a diverse group of aquatic, photosynthetic organisms, generally categorized as either macroalgae (i.e. seaweed) or microalgae. Microalgae constitute a spectacularly diverse group of prokaryotic and eukaryotic unicellular organisms and account for approximately 50% of global organic carbon fixation. The PIâ??s have subdivided the proposed research program into three main research areas, all of which are essential to the development of commercially viable algae fuels compatible with current energy infrastructure. In the fuel development focus, catalytic cracking reactions of algae oils is optimized. In the species development project, genetic engineering is used to create microalgae strains that are capable of high-level hydrocarbon production. For the modeling effort, the construction of multi-scaled models of algae production was prioritized, including integrating small-scale hydrodynamic models of algae production and reactor design and large-scale design optimization models.

Crunkleton, Daniel; Price, Geoffrey; Johannes, Tyler; Cremaschi, Selen

2012-12-03

39

FL47CH15-Goldstein ARI 25 November 2014 9:45 Green Algae as Model  

E-print Network

FL47CH15-Goldstein ARI 25 November 2014 9:45 Green Algae as Model Organisms for Biological Fluid green algae, spanning from the unicellular Chlamydomonas to multicellular Volvox, have emerged as model of flagellar synchronization. Green algae are well suited to the study of such problems because of their range

Goldstein, Raymond E.

40

Xylochloris irregularis gen. et sp. nov. (Trebouxiophyceae, Chlorophyta), a novel subaerial coccoid green alga  

E-print Network

green alga JIR I´ NEUSTUPA 1 *, MAREK ELIA´ S1 , PAVEL SKALOUD 1 , YVONNE NE MCOVA´ 1 AND LENKA irregularis gen. et sp. nov. (Trebouxiophyceae, Chlorophyta), a novel subaerial coccoid green alga. Phycologia 50: 57­66. DOI: 10.2216/08-64.1 The phylogenetic diversity of subaerial coccoid green algae remains

41

The central role of the green alga Chlamydomonas reinhardtii in revealing the mechanism of state transitions  

E-print Network

The central role of the green alga Chlamydomonas reinhardtii in revealing the mechanism of state Abstract This review focuses on the essential role played by the green alga Chlamydomonas reinhardtii of the two photo- systems with changes in the spectral composition of light. In plants and green algae, state

42

ORIGINAL ARTICLE tla1, a DNA insertional transformant of the green alga  

E-print Network

ORIGINAL ARTICLE tla1, a DNA insertional transformant of the green alga Chlamydomonas reinhardtii of the green alga Chlamydomonas reinhardtii was employed to isolate tla1, a stable transformant having conversion efficiency and photosynthetic productivity of the mass culture. Green algae growing under full

Polle, Jürgen

43

The ultrasmall green alga Ostreococcus unveils a unique regulation of the Calvin cycle  

E-print Network

The ultrasmall green alga Ostreococcus unveils a unique regulation of the Calvin cycle Steven: nuclear encoded GapA: cyanobacterial (plastid) ancestor transition from green algae to land plants Origin:1109-1118, (2006)) Ostreococcus tauri is a unicellular green alga, belonging to the Prasinophyceae. With a size

Gent, Universiteit

44

YSI Blue-Green Algae (BGA) Sensors Spatial Water Quality Mapping of the Potomac River Estuary  

E-print Network

YSI Blue-Green Algae (BGA) Sensors Spatial Water Quality Mapping of the Potomac River Estuary Visit integrated Yellow Spring Instruments (YSI) blue- green algae (BGA) sensors into our system to evaluate of blue-green algae ·Observed phycocyanin containing organisms were mainly colony forming (e

Boynton, Walter R.

45

Manipulating RuBisCO accumulation in the green alga, Chlamydomonas reinhardtii  

E-print Network

Manipulating RuBisCO accumulation in the green alga, Chlamydomonas reinhardtii Xenie Johnson between green algae (Chlamydomonas X. Johnson (&) Centre National de la Recherche Scientifique, Unite predicted PPR repeats in green algae and land plants, and the other, ``C-domain'' , is similarly composed

46

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

47

A green Paramecium strain with abnormal growth of symbiotic algae.  

PubMed

Some hundred cells of Chlorella-like green algae are naturally enclosed within the cytoplasm of a single cell of green paramecia (Paramecium bursaria). Therefore, P. bursaria serves as an experimental model for studying the nature of endo-symbiosis made up through chemical communication between the symbiotic partners. For studying the mechanism of symbiotic regulations, the materials showing successful symbiosis are widely used. Apart from such successful model materials, some models for symbiotic distortion would be of great interest in order to understand the nature of successful symbiosis. Here, we describe a case of unsuccessful symbiosis causing unregulated growth of algae inside the hosting ciliates. Recently, we have screened some cell lines, from the mass of P. bursaria cells survived after paraquat treatment. The resultant cell lines (designated as KMZ series) show novel and unusual morphological features with heavily darker green colour distinguishable from the original pale green-coloured paramecia. In this type of isolates, endo-symbiotic algae are restricted within one or two dense spherical structures located at the center of the host cells' cytoplasm. Interestingly, this isolate maintains the host cells' circadian mating response which is known as an alga-dependent behaviour in the host cells. In contrast, we discuss that KMZ lacks the host-dependent regulation of algal growth, thus the algal complex often over-grows obviously exceeding the original size of the normal hosting ciliates. Additionally, possible use of this isolate as a novel model for symbiotic cell-to-cell communication is discussed. PMID:21319710

Irie, Kanami; Furukawa, Shunsuke; Kadono, Takashi; Kawano, Tomonori

2010-01-01

48

Photosynthetic hydrogen and oxygen production by green algae  

Microsoft Academic Search

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.

E. Greenbaum; J. W. Lee

1997-01-01

49

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

50

Are the green algae (phylum Viridiplantae) two billion years old?  

Microsoft Academic Search

In his book, Life on a young planet, A.H. KNOLL states that the first documented fossils of green algae date back 750 Ma. However, according to B. TEYSSČDRE's book, La vie invisible, they are much older. Using a method which combines paleontology and molecular phylogeny, this paper is an inquiry into the Precambrian fossils of some \\

Bernard TEYSSČDRE

2006-01-01

51

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

52

Oleosin of subcellular lipid droplets evolved in green algae.  

PubMed

In primitive and higher plants, intracellular storage lipid droplets (LDs) of triacylglycerols are stabilized with a surface layer of phospholipids and oleosin. In chlorophytes (green algae), a protein termed major lipid-droplet protein (MLDP) rather than oleosin on LDs was recently reported. We explored whether MLDP was present directly on algal LDs and whether algae had oleosin genes and oleosins. Immunofluorescence microscopy revealed that MLDP in the chlorophyte Chlamydomonas reinhardtii was associated with endoplasmic reticulum subdomains adjacent to but not directly on LDs. In C. reinhardtii, low levels of a transcript encoding an oleosin-like protein (oleolike) in zygotes-tetrads and a transcript encoding oleosin in vegetative cells transferred to an acetate-enriched medium were found in transcriptomes and by reverse transcription-polymerase chain reaction. The C. reinhardtii LD fraction contained minimal proteins with no detectable oleolike or oleosin. Several charophytes (advanced green algae) possessed low levels of transcripts encoding oleosin but not oleolike. In the charophyte Spirogyra grevilleana, levels of oleosin transcripts increased greatly in cells undergoing conjugation for zygote formation, and the LD fraction from these cells contained minimal proteins, two of which were oleosins identified via proteomics. Because the minimal oleolike and oleosins in algae were difficult to detect, we tested their subcellular locations in Physcomitrella patens transformed with the respective algal genes tagged with a Green Fluorescent Protein gene and localized the algal proteins on P. patens LDs. Overall, oleosin genes having weak and cell/development-specific expression were present in green algae. We present a hypothesis for the evolution of oleosins from algae to plants. PMID:23391579

Huang, Nan-Lan; Huang, Ming-Der; Chen, Tung-Ling L; Huang, Anthony H C

2013-04-01

53

Chemical control of eucaryotic and blue-green algae in anaerobic photoreactors culturing Rhodospirillaceae  

Microsoft Academic Search

Summary To control the growth of eurocaryotic and blue-green algae in anaerobic reactors of photosynthetically grown Rhodospirillaceae, the effect of algae inhibitors with different modes of action was examined. Tests were performed with mixed populations of green algae and blue-green algae, besides strains of the purple nonsulphur bacteriaRhodopseudomonas capsulata, Rhodospirillum rubrum andRhodomicrobium vannielii. Chloroxuron, a urea-derivative, was found to inhibit

L. Segers; W. Verstraete

1985-01-01

54

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

55

Carnets de Gologie / Notebooks on Geology -Article 2006/03 (CG2006_A03) Are the green algae (phylum Viridiplantae)  

E-print Network

Carnets de Géologie / Notebooks on Geology - Article 2006/03 (CG2006_A03) 1 Are the green algae planet, A.H. KNOLL states that the first documented fossils of green algae date back 750 Ma. However" and of a primitive clade of green algae, the Pyramimonadales. A paraphyletic group of unicellular green algae, named

Paris-Sud XI, Université de

56

Green Algae as Model Organisms for Biological Fluid Dynamics  

E-print Network

In the past decade the volvocine green algae, spanning from the unicellular $Chlamydomonas$ to multicellular $Volvox$, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 $\\mu$m to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these re...

Goldstein, Raymond E

2014-01-01

57

Green Algae as Model Organisms for Biological Fluid Dynamics  

E-print Network

In the past decade the volvocine green algae, spanning from the unicellular $Chlamydomonas$ to multicellular $Volvox$, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 $\\mu$m to several millimetres), their geometric regularity, the ease with which they can be cultured and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these remarkable organisms.

Raymond E. Goldstein

2014-09-08

58

Green Algae as Model Organisms for Biological Fluid Dynamics  

NASA Astrophysics Data System (ADS)

In the past decade, the volvocine green algae, spanning from the unicellular Chlamydomonas to multicellular Volvox, have emerged as model organisms for a number of problems in biological fluid dynamics. These include flagellar propulsion, nutrient uptake by swimming organisms, hydrodynamic interactions mediated by walls, collective dynamics and transport within suspensions of microswimmers, the mechanism of phototaxis, and the stochastic dynamics of flagellar synchronization. Green algae are well suited to the study of such problems because of their range of sizes (from 10 ?m to several millimeters), their geometric regularity, the ease with which they can be cultured, and the availability of many mutants that allow for connections between molecular details and organism-level behavior. This review summarizes these recent developments and highlights promising future directions in the study of biological fluid dynamics, especially in the context of evolutionary biology, that can take advantage of these remarkable organisms.

Goldstein, Raymond E.

2015-01-01

59

Facts about Cyanobacteria (Blue-green Algae) and Cyanobacterial Harmful Algal Blooms  

E-print Network

#12;1 Facts about Cyanobacteria (Blue-green Algae) and Cyanobacterial Harmful Algal Blooms (CyanoHABs) Cyanobacteria (blue-green algae) Cyanobacteria are bacteria and how they form Cyanobacterial blooms occur when algae that are normally present grow exuberantly

60

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

E-print Network

by comparison with the relatively small genomes of the closely related green algae Chlorella and CoccomyxaA Lack of Parasitic Reduction in the Obligate Parasitic Green Alga Helicosporidium Jean-dependence. This is evident in many parasites, but perhaps the most extreme transitions are from free-living autotrophic algae

Keeling, Patrick

61

Hylodesmus singaporensis gen. et sp. nov., a new autosporic subaerial green alga (Scenedesmaceae,  

E-print Network

Hylodesmus singaporensis gen. et sp. nov., a new autosporic subaerial green alga (Scenedesmaceae characterization of an autosporic coccoid green alga isolated from decaying wood in a natural forest in Singapore. Depending on culture conditions, this alga formed globular to irregularly oval solitary cells

62

Chloroplast sulfate transport in green algae – genes, proteins and effects  

Microsoft Academic Search

This review summarizes evidence at the molecular genetic, protein and regulatory levels concerning the existence and function\\u000a of a putative ABC-type chloroplast envelope-localized sulfate transporter in the model unicellular green alga Chlamydomonas reinhardtii. From the four nuclear genes encoding this sulfate permease holocomplex, two are coding for chloroplast envelope-targeted\\u000a transmembrane proteins (SulP and SulP2), a chloroplast stroma-targeted ATP-binding protein (Sabc)

Anastasios Melis; Hsu-Ching Chen

2005-01-01

63

The problems of Prochloron. [evolution of green algae  

NASA Technical Reports Server (NTRS)

Prokaryotic green algae (prochlorophytes), which contain chlorophylls a and b but no bilin pigments, may be phylogenetically related to ancestral chloroplasts if symbiogenesis occurred. They may be otherwise related to eukaryotic chlorophytes. They could have evolved from cyanophytes by loss of phycobilin and gain of chlorophyll b synthesis. These possibilities are briefly discussed. Relevant evidence from biochemical studies in many collaborative laboratories is now becoming available for the resolution of such questions.

Lewin, R. A.

1983-01-01

64

Effects of tetrabromobisphenol A on the green alga Chlorella pyrenoidosa  

Microsoft Academic Search

Flow cytometry (FC) was used to determine effects of tetrabromobisphenol A (TBBPA) on the green alga Chlorella pyrenoidosa (C. pyrenoidosa) by evaluating esterase activity, membrane integrity, concentrations of intracellular reactive oxygen species (ROS) and chlorophyll a (Chl-a) auto-fluorescence. TBBPA can inhibit esterase activity. Esterase activity was inversely proportional with TBBPA with a 24 h EC50 value of 3.13 mg TBBPA\\/L.

Hongling Liu; Yang Yu; Fanxiang Kong; Luning He; Hongxia Yu; John P. Giesy; Xiaorong Wang

2008-01-01

65

Production of carbonate sediments by a unicellular green alga  

Microsoft Academic Search

This study investigates the ability of the unicellular green alga Nannochloris atomusto precipitate CaCO3, quantifies mineral precipitation rates, estimates sediment production in a N. atomus 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 pa-

KIMBERLY K. YATES; LISA L. ROBBINS

1998-01-01

66

Green algae in tundra soils affected by coal mine pollutions  

Microsoft Academic Search

Green algal communities were investigated in clean and pollution-impacted tundra soils around the large coal mine industrial\\u000a complex of Vorkuta in the E. European Russian tundra. Samples were collected in three zones of open-cast coal mining with\\u000a different degrees of pollution-impacted soil transformation. A total of 42 species of algae were found in all zones. The species\\u000a richness decreased from

Elena N. Patova; Marina F. Dorokhova

2008-01-01

67

Green algae and the origin of land plants  

Microsoft Academic Search

Over the past two decades, molecular phylogenetic data have allowed evaluations of hypotheses on the evolution of green algae based on vegetative morphological and ultrastructural characters. Higher taxa are now generally recognized on the basis of ultrastruc- tural characters. Molecular analyses have mostly employed primarily nuclear small subunit rDNA (18S) and plastid rbcL data, as well as data on intron

LOUISE A. LEWIS; RICHARD M. MCCOURT

2004-01-01

68

How the green alga Chlamydomonas reinhardtii keeps time  

Microsoft Academic Search

The unicellular green alga Chlamydomonas reinhardtii has two flagella and a primitive visual system, the eyespot apparatus, which allows the cell to phototax. About 40 years\\u000a ago, it was shown that the circadian clock controls its phototactic movement. Since then, several circadian rhythms such as\\u000a chemotaxis, cell division, UV sensitivity, adherence to glass, or starch metabolism have been characterized. The availability

Thomas Schulze; Katja Prager; Hannes Dathe; Juliane Kelm; Peter Kießling; Maria Mittag

2010-01-01

69

Multicellularity in green algae: upsizing in a walled complex  

PubMed Central

Modern green algae constitute a large and diverse taxonomic assemblage that encompasses many multicellular phenotypes including colonial, filamentous, and parenchymatous forms. In all multicellular green algae, each cell is surrounded by an extracellular matrix (ECM), most often in the form of a cell wall. Volvocalean taxa like Volvox have an elaborate, gel-like, hydroxyproline rich glycoprotein covering that contains the cells of the colony. In “ulvophytes,” uronic acid-rich and sulfated polysaccharides are the likely adhesion agents that maintain the multicellular habit. Charophytes also produce polysaccharide-rich cell walls and in late divergent taxa, pectin plays a critical role in cell adhesion in the multicellular complex. Cell walls are products of coordinated interaction of membrane trafficking, cytoskeletal dynamics and the cell’s signal transduction machinery responding both to precise internal clocks and external environmental cues. Most often, these activities must be synchronized with the secretion, deposition and remodeling of the polymers of the ECM. Rapid advances in molecular genetics, cell biology and cell wall biochemistry of green algae will soon provide new insights into the evolution and subcellular processes leading to multicellularity. PMID:25477895

Domozych, David S.; Domozych, Catherine E.

2014-01-01

70

Multicellularity in green algae: upsizing in a walled complex.  

PubMed

Modern green algae constitute a large and diverse taxonomic assemblage that encompasses many multicellular phenotypes including colonial, filamentous, and parenchymatous forms. In all multicellular green algae, each cell is surrounded by an extracellular matrix (ECM), most often in the form of a cell wall. Volvocalean taxa like Volvox have an elaborate, gel-like, hydroxyproline rich glycoprotein covering that contains the cells of the colony. In "ulvophytes," uronic acid-rich and sulfated polysaccharides are the likely adhesion agents that maintain the multicellular habit. Charophytes also produce polysaccharide-rich cell walls and in late divergent taxa, pectin plays a critical role in cell adhesion in the multicellular complex. Cell walls are products of coordinated interaction of membrane trafficking, cytoskeletal dynamics and the cell's signal transduction machinery responding both to precise internal clocks and external environmental cues. Most often, these activities must be synchronized with the secretion, deposition and remodeling of the polymers of the ECM. Rapid advances in molecular genetics, cell biology and cell wall biochemistry of green algae will soon provide new insights into the evolution and subcellular processes leading to multicellularity. PMID:25477895

Domozych, David S; Domozych, Catherine E

2014-01-01

71

The super-excess energy dissipation in diatom algae: comparative analysis with higher plants.  

PubMed

When grown at intermittent light regime, diatom alga Phaeodactylum tricornutum is able to form photoprotective non-photochemical chlorophyll fluorescence quenching (NPQ) three to five times larger than that observed in the higher plants. This quenching is sustained in the dark for 5 to 10 min, reverses completely within approximately 1 h and seems to be very tightly related to the presence of the zeaxanthin analogue, diatoxanthin. Addition of the uncoupler NH4Cl before illumination can completely abolish formation of NPQ, revealing the DeltapH-dependency of the xanthophyll cycle activity. Once established, NPQ can also be almost completely reversed by the uncoupler. However, the higher NPQ is formed the more time is required for its reversal. At the point when the fluorescence was approximately 90% recovered the level of illumination-induced diatoxanthin was found to be only partially reduced. This indicates that the proton gradient is a key triggering factor of NPQ. It was also noticed that NPQ in Phaeodactylum cells was absent even when majority of reaction centers were closed and the plastoquinone pool was significantly reduced. The absence of NPQ at these conditions could be due to very low levels of DeltapH. It is likely that in diatoms alternative sources of protons such as the PS I cyclic electron transfer and/or chlororespiration are important in generating the proton gradient sufficient to trigger NPQ. Absorption changes associated with the xanthophyll cycle activity were found to be larger than those for higher plants. The position of the positive maximum in the difference spectrum illuminated-minus-dark was 512-514 nm in comparison to the 505-508 nm for leaves. The 535 nm band associated with NPQ in plants is absent in Phaeodactylum. An uncoupler-sensitive absorption change at 522 nm was discovered. Kinetics of NPQ showed linear correlation with the 522 nm absorption change. PMID:16151872

Ruban, Alexander; Lavaud, Johann; Rousseau, Bernard; Guglielmi, Gerard; Horton, Peter; Etienne, Anne-Lise

2004-01-01

72

Effect of tetramethyl lead on freshwater green algae.  

PubMed

The toxicity of tetramethyl lead (Me4Pb) towards freshwater algae was studied by bubbling biologically generated Me4Pb from one flask containing 5 mg of Pb 1-1 as Me3PbOAc into the culture medium in another flask where a test alga Scenedesmus quadricauda was grown. As Me4Pb is not soluble in water and is volatile, the exposure of an alga to this lead compound was only momentary. It was estimated that less than 0.5 mg of Pb(Me4Pb) had passed through the culture medium. The primary productivity and cell growth (determined by dry weight), however, decreased by 85% and 32% respectively, as compared with the controls without exposure to Me4Pb. Furthermore, cells exposed to Me4Pb tended to clump together and striking alterations in cell fine-structure were observed. An electron microscopic analysis by an energy dispersive spectrometer revealed that Pb ions had penetrated the cell and were deposited within concretion bodies. Similar results were obtained with the green algae Ankistrodesmus falcatus and Chlorella pyrenoidosa. PMID:869587

Silverberg, B A; Wong, P T; Chau, Y K

1977-01-01

73

Intracellular invasion of green algae in a salamander host  

PubMed Central

The association between embryos of the spotted salamander (Ambystoma maculatum) and green algae (“Oophila amblystomatis” Lamber ex Printz) has been considered an ectosymbiotic mutualism. We show here, however, that this symbiosis is more intimate than previously reported. A combination of imaging and algal 18S rDNA amplification reveals algal invasion of embryonic salamander tissues and cells during development. Algal cells are detectable from embryonic and larval Stages 26–44 through chlorophyll autofluorescence and algal 18S rDNA amplification. Algal cell ultrastructure indicates both degradation and putative encystment during the process of tissue and cellular invasion. Fewer algal cells were detected in later-stage larvae through FISH, suggesting that the decline in autofluorescent cells is primarily due to algal cell death within the host. However, early embryonic egg capsules also contained encysted algal cells on the inner capsule wall, and algal 18S rDNA was amplified from adult reproductive tracts, consistent with oviductal transmission of algae from one salamander generation to the next. The invasion of algae into salamander host tissues and cells represents a unique association between a vertebrate and a eukaryotic alga, with implications for research into cell–cell recognition, possible exchange of metabolites or DNA, and potential congruence between host and symbiont population structures. PMID:21464324

Kerney, Ryan; Kim, Eunsoo; Hangarter, Roger P.; Heiss, Aaron A.; Bishop, Cory D.; Hall, Brian K.

2011-01-01

74

Intracellular invasion of green algae in a salamander host.  

PubMed

The association between embryos of the spotted salamander (Ambystoma maculatum) and green algae ("Oophila amblystomatis" Lamber ex Printz) has been considered an ectosymbiotic mutualism. We show here, however, that this symbiosis is more intimate than previously reported. A combination of imaging and algal 18S rDNA amplification reveals algal invasion of embryonic salamander tissues and cells during development. Algal cells are detectable from embryonic and larval Stages 26-44 through chlorophyll autofluorescence and algal 18S rDNA amplification. Algal cell ultrastructure indicates both degradation and putative encystment during the process of tissue and cellular invasion. Fewer algal cells were detected in later-stage larvae through FISH, suggesting that the decline in autofluorescent cells is primarily due to algal cell death within the host. However, early embryonic egg capsules also contained encysted algal cells on the inner capsule wall, and algal 18S rDNA was amplified from adult reproductive tracts, consistent with oviductal transmission of algae from one salamander generation to the next. The invasion of algae into salamander host tissues and cells represents a unique association between a vertebrate and a eukaryotic alga, with implications for research into cell-cell recognition, possible exchange of metabolites or DNA, and potential congruence between host and symbiont population structures. PMID:21464324

Kerney, Ryan; Kim, Eunsoo; Hangarter, Roger P; Heiss, Aaron A; Bishop, Cory D; Hall, Brian K

2011-04-19

75

Fact Sheet on Toxic Blue-green Algae Carole A. Lembi Department of Botany and Plant Pathology  

E-print Network

Fact Sheet on Toxic Blue-green Algae Carole A. Lembi Department of Botany and Plant Pathology Purdue University What are blue-green algae? Blue-greens are very primitive organisms that are not really algae. They photosynthesize like algae, but they are actually bacteria. Scientists refer to them

76

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

77

Effect of Bacteria Associated with the Green Alga Ulva reticulata on Marine Micro and Macrofouling  

Microsoft Academic Search

The green alga Ulva reticulata (Forsskal) is often free from biofouling in Hong Kong waters. An early study indicated that bioactive substances from this alga inhibit settlement of the polychaete Hydroides elegans (Haswell). It is also predicted that epibiotic bacteria protect this alga from micro- and macrofouling. In this study, bacterial strains from the surface of U. reticulata were isolated

Sergey V Dobretsov; Pei-Yuan Qian

2002-01-01

78

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

79

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

80

Codon Usage in Higher Plants, Green Algae, and Cyanobacteria 1  

PubMed Central

Codon usage is the selective and nonrandom use of synonymous codons by an organism to encode the amino acids in the genes for its proteins. During the last few years, a large number of plant genes have been cloned and sequenced, which now permits a meaningful comparison of codon usage in higher plants, algae, and cyanobacteria. For the nuclear and organellar genes of these organisms, a small set of preferred codons are used for encoding proteins. Codon usage is different for each genome type with the variation mainly occurring in choices between codons ending in cytidine (C) or guanosine (G) versus those ending in adenosine (A) or uridine (U). For organellar genomes, chloroplastic and mitochrondrial proteins are encoded mainly with codons ending in A or U. In most cyanobacteria and the nuclei of green algae, proteins are encoded preferentially with codons ending in C or G. Although only a few nuclear genes of higher plants have been sequenced, a clear distinction between Magnoliopsida (dicot) and Liliopsida (monocot) codon usage is evident. Dicot genes use a set of 44 preferred codons with a slight preference for codons ending in A or U. Monocot codon usage is more restricted with an average of 38 codons preferred, which are predominantly those ending in C or G. But two classes of genes can be recognized in monocots. One set of monocot genes uses codons similar to those in dicots, while the other genes are highly biased toward codons ending in C or G with a pattern similar to nuclear genes of green algae. Codon usage is discussed in relation to evolution of plants and prospects for intergenic transfer of particular genes. PMID:16667228

Campbell, Wilbur H.; Gowri, G.

1990-01-01

81

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

82

Mass Spawning by Green Algae on Coral Reefs Kenneth E. Clifton*  

E-print Network

Mass Spawning by Green Algae on Coral Reefs Kenneth E. Clifton* Predawn episodes of mass spawning by green algae (up to nine species in five genera on a single morning) intermittently cloud Caribbean and predictably on a given morning, with closely related species spawning at different times. Algal sexual

Clifton, Ken

83

The comparative aspects of cell wall chemistry in the green algae ( chlorophyta )  

Microsoft Academic Search

Summary The origin of a cell wall was an event of fundamental importance in the evolution of plants. In the green algae, cell walls apparently had independent origins in at least three lines of evolution. In this paper, the components of the cell wall were determined and compared in four filamentous green algae representing the charophycean, chlorophycean and ulvacean evolutionary

David S. Domozych; Kenneth D. Stewart; Karl R. Mattox

1980-01-01

84

Fitness and Complexity in Volvocalean Green Algae Cristian A. Solari1  

E-print Network

Fitness and Complexity in Volvocalean Green Algae Cristian A. Solari1 , Aurora M. Nedelcu2 ­fecundity and viability­ as size increases. We use volvocalean green algae as a model system to compare-soma specialization is achieved. Our results show that the cost of reproduction plays an important role

Nedelcu, Aurora M.

85

Gain and loss of polyadenylation signals during evolution of green algae  

Microsoft Academic Search

BACKGROUND: The Viridiplantae (green algae and land plants) consist of two monophyletic lineages: the Chlorophyta and the Streptophyta. Most green algae belong to the Chlorophyta, while the Streptophyta include all land plants and a small group of freshwater algae known as Charophyceae. Eukaryotes attach a poly-A tail to the 3' ends of most nuclear-encoded mRNAs. In embryophytes, animals and fungi,

Sabina Wodniok; Andreas Simon; Gernot Glöckner; Burkhard Becker

2007-01-01

86

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

87

MOLECULAR CHARACTERIZATION OF THE ASSIMILATORY NITRATE REDUCTASE GENE AND ITS EXPRESSION IN THE MARINE GREEN ALGA DUNALIELLA  

E-print Network

IN THE MARINE GREEN ALGA DUNALIELLA TERTIOLECTA (CHLOROPHYCEAE)1 Bongkeun Song2 and Bess B. Ward Department from a marine phytoplankton, the green alga Dunaliella tertiolecta Butcher. Its sequence is very similar to that of the other green algae, but its intron structure and transcriptional regulation differ

Ward, Bess

88

Unique Regulation of the Calvin Cycle in the Ultrasmall Green Alga Ostreococcus Steven Robbens,1,2  

E-print Network

Unique Regulation of the Calvin Cycle in the Ultrasmall Green Alga Ostreococcus Steven Robbens,1 to be generally present in the Plantae (glaucophytes, red and green algae, and plants), up to now GapB was exclusively found in Streptophyta, including the enigmatic green alga Mesostigma viride. However, here we show

Gent, Universiteit

89

Molecular Characterization of Epiphytic Bacterial Communities on Charophycean Green Algae  

PubMed Central

Epiphytic bacterial communities within the sheath material of three filamentous green algae, Desmidium grevillii, Hyalotheca dissiliens, and Spondylosium pulchrum (class Charophyceae, order Zygnematales), collected from a Sphagnum bog were characterized by PCR amplification, cloning, and sequencing of 16S ribosomal DNA. A total of 20 partial sequences and nine different sequence types were obtained, and one sequence type was recovered from the bacterial communities on all three algae. By phylogenetic analysis, the cloned sequences were placed into several major lineages of the Bacteria domain: the Flexibacter/Cytophaga/Bacteroides phylum and the ?, ?, and ? subdivisions of the phylum Proteobacteria. Analysis at the subphylum level revealed that the majority of our sequences were not closely affiliated with those of known, cultured taxa, although the estimated evolutionary distances between our sequences and their nearest neighbors were always less than 0.1 (i.e., greater than 90% similar). This result suggests that the majority of sequences obtained in this study represent as yet phenotypically undescribed bacterial species and that the range of bacterial-algal interactions that occur in nature has not yet been fully described. PMID:9797295

Fisher, Madeline M.; Wilcox, Lee W.; Graham, Linda E.

1998-01-01

90

Antiprotozoal, antimycobacterial and cytotoxic potential of some british green algae.  

PubMed

In the continuation of our search for natural sources for antiprotozoal and antitubercular molecules, we have screened the crude extracts of four green marine algae (Cladophora rupestris, Codium fragile ssp. tomentosoides, Ulva intestinalis and Ulva lactuca) collected from the Dorset area of England. Trypanosoma brucei rhodesiense, Trypanosoma cruzi, Leishmania donovani and Mycobacterium tuberculosis were used as test organisms in the in vitro assays. The selective toxicity of the extracts was also determined toward mammalian skeletal myoblast (L6) cells. The crude seaweed extracts had no activity against M. tuberculosis, but showed antiprotozoal activity against at least two protozoan species. All algal extracts were active against T. brucei rhodesiense, with C. rupestris being the most potent one (IC(50) value 3.7 microg/ml), whilst only C. rupestris and U. lactuca had moderate trypanocidal activity against T. cruzi (IC(50) values 80.8 and 34.9 microg/ml). Again, all four extracts showed leishmanicidal activity with IC(50) values ranging between 12.0 and 20.2 microg/ml. None of the extracts showed cytotoxicity toward L6 cells, indicating that their antiprotozoal activity is specific. This is the first study reporting antiprotozoal and antimycobacterial activity of British marine algae. PMID:19960429

Spavieri, Jasmine; Kaiser, Marcel; Casey, Rosalyn; Hingley-Wilson, Suzie; Lalvani, Ajit; Blunden, Gerald; Tasdemir, Deniz

2010-07-01

91

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. PMID:24710110

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

2014-01-01

92

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

93

Green Chemistry COMMUNICATION  

E-print Network

Green Chemistry COMMUNICATION Cite this: Green Chem., 2013, 15, 2060 Received 8th April 2013 platforms.16 We demonstrate that the frustules of unicellular algae known as diatoms can be used 5042, Australia. E-mail: colin.raston@flinders.edu.au; Tel: +08 8021 7958 2060 | Green Chem., 2013, 15

94

Green algae and the origins of multicellularity in the plant kingdom.  

PubMed

The green lineage of chlorophyte algae and streptophytes form a large and diverse clade with multiple independent transitions to produce multicellular and/or macroscopically complex organization. In this review, I focus on two of the best-studied multicellular groups of green algae: charophytes and volvocines. Charophyte algae are the closest relatives of land plants and encompass the transition from unicellularity to simple multicellularity. Many of the innovations present in land plants have their roots in the cell and developmental biology of charophyte algae. Volvocine algae evolved an independent route to multicellularity that is captured by a graded series of increasing cell-type specialization and developmental complexity. The study of volvocine algae has provided unprecedented insights into the innovations required to achieve multicellularity. PMID:25324214

Umen, James G

2014-11-01

95

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

96

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

PubMed

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. PMID:22639667

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

2012-01-01

97

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. PMID:22639667

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

2012-01-01

98

Cryptic Sex in the Smallest Eukaryotic Marine Green Alga Nigel Grimsley,1,2  

E-print Network

, are colinear and densely packed with coding sequences, but no sexual life cycle has been described. SeventeenCryptic Sex in the Smallest Eukaryotic Marine Green Alga Nigel Grimsley,1,2 Be´range`re Pe´quin,1 Ostreococcus spp. are common worldwide oceanic picoeukaryotic pelagic algae. The complete genomes of three

99

Nitrogen Limitation and Slow Drying Induce Desiccation Tolerance in Conjugating Green Algae  

E-print Network

, rather than specialized stages of the life cycle, can be hardened by mild desiccation stress to surviveNitrogen Limitation and Slow Drying Induce Desiccation Tolerance in Conjugating Green Algae. Algae were cultivated in liquid or on solidified medium (9 weeks), supplemented with or lacking nitrogen

100

Isotopic relationships between saponifiable lipids and cellulose nitrate prepared from red, brown and green algae  

Microsoft Academic Search

Stable carbon and hydrogen isotope ratios were determined for the saponifiable lipid fraction as well as the cellulose fraction (the latter after nitration to remove exchangeable hydrogens) of several species of red, brown and green algae from three locations. A significant correlation was observed between the hydrogen isotope ratios of cellulose nitrate and saponifiable lipid for red algae, but not

L. Sternberg; M. J. Niro; H. O. Ajie

1986-01-01

101

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

Microsoft Academic Search

The endophytic green alga Acrochaete operculata completely colonizes the sporophytes of the red alga Chondrus cris- pus ; 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.

Kamal Bouarab; Philippe Potin; Juan Correa; Bernard Kloareg

1999-01-01

102

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

103

JENUFA GEN. NOV.: A NEW GENUS OF COCCOID GREEN ALGAE (CHLOROPHYCEAE, INCERTAE SEDIS) PREVIOUSLY RECORDED BY ENVIRONMENTAL SEQUENCING1  

E-print Network

JENUFA GEN. NOV.: A NEW GENUS OF COCCOID GREEN ALGAE (CHLOROPHYCEAE, INCERTAE SEDIS) PREVIOUSLY of unicellular green algae from algal biofilms growing on tree bark in a Southeast Asian tropical rainforest: AU, approximately unbiased; BBM, Bold basal medium; CAUP, Culture Collection of algae at Charles

104

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

105

Biochemical Basis ofObligate Autotrophy in Blue-Green Algae andThiobacilli  

Microsoft Academic Search

Differential rates ofincorporation ofsugars,organic acids, andaminoacids during autotrophic growth ofseveral blue-green algae andthiobacilli havebeendetermined. Inobligate autotrophs (both blue-green algae andthiobacilli), exogenously fur- nished organic compounds makea verysmallcontribution tocellular carbon; ace- tate, themostreadily incorporated compound ofthose studied, contributes about 10% ofnewlysynthesized cellular carbon. InThiobacillus intermedius, a facultative chemoautotroph, acetate contributes over40%ofnewly synthesized cellular carbon, andsuccinate andglutamate almost 90%.Intheobligate autotrophs, carbon from

ARNOLD J. SMITH; ROGER Y. STANIER

1967-01-01

106

Channelrhodopsin-1: A Light-Gated Proton Channel in Green Algae  

Microsoft Academic Search

Phototaxis and photophobic responses of green algae are mediated by rhodopsins with microbial-type chromophores. We report a complementary DNA sequence in the green alga Chlamydomonas reinhardtii that encodes a microbial opsin-related protein, which we term Channelopsin-1. The hydrophobic core region of the protein shows homology to the light-activated proton pump bacteriorhodopsin. Expression of Channelopsin-1, or only the hydrophobic core, in

Georg Nagel; Doris Ollig; Markus Fuhrmann; Suneel Kateriya; Anna Maria Musti; Ernst Bamberg; Peter Hegemann

2002-01-01

107

Bioelectricity generation and microcystins removal in a blue-green algae powered microbial fuel cell  

Microsoft Academic Search

Bioelectricity production from blue-green algae was examined in a single chamber tubular microbial fuel cell (MFC). The blue-green algae powered MFC produced a maximum power density of 114mW\\/m2 at a current density of 0.55mA\\/m2. Coupled with the bioenergy generation, high removal efficiencies of chemical oxygen demand (COD) and nitrogen were also achieved in MFCs. Over 78.9% of total chemical oxygen

Yong Yuan; Qing Chen; Shungui Zhou; Li Zhuang; Pei Hu

2011-01-01

108

Toxicity Assessment of Expired Pesticides to Green Algae Pseudokirchneriella subcapitata  

PubMed Central

In order to investigate the effect of expired pesticides on the yield and growth rate of green algae Pseudokirchneriella subcapitata, a study was conducted as per the Organisation for Economic Cooperation and Development (OECD) guideline number 201. Fifteen expired pesticide formulations, most commonly used in Indian agriculture, were tested in comparison with their unexpired counterparts. The expired pesticide formulations studied belonged to various class and functional groups: organophosphate, pyrethroid-based insecticides; azole-based fungicides; acetamide, propionate, acetic acid-based herbicides; fungicides mixtures containing two actives—azole and dithiocarbamate. The toxicity endpoints of yield (EyC50: 0–72 h) and growth rate (ErC50: 0–72 h) of Pseudokirchneriella subcapitata for each pesticide formulation (both expired and unexpired pesticides) were determined statistically using TOXSTAT 3.5 version software. The results pointed out that some expired pesticide formulations exhibited higher toxicity to tested algal species, as compared to the corresponding unexpired pesticides. These data thus stress the need for greater care to dispose expired pesticides to water bodies, to avoid the effects on aquatic ecospecies tested. PMID:23762633

Satyavani, G.; Chandrasehar, G.; Varma, K. Krishna; Goparaju, A.; Ayyappan, S.; Reddy, P. Neelakanta; Murthy, P. Balakrishna

2012-01-01

109

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. PMID:19342428

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

2009-01-01

110

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. PMID:9701590

Hiltonen, Thomas; Björkbacka, Harry; Forsman, Cecilia; Clarke, Adrian K.; Samuelsson, Göran

1998-01-01

111

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

112

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

113

The impact of differing cell and algogenic organic matter (AOM) characteristics on the coagulation and flotation of algae  

Microsoft Academic Search

The aim of this study was to compare the coagulation and flotation of different algae species with varying morphology and algogenic organic matter (AOM) composition in order to link physical and chemical algae characteristics to treatment. Microcystis aeruginosa (cyanobacteria), Chlorella vulgaris (green algae), Asterionella formosa and Melosira sp. (diatoms) were treated by coagulation with aluminium sulphate and flotation. The AOM

Rita K. Henderson; Simon A. Parsons; Bruce Jefferson

2010-01-01

114

Assimilatory nitrate reductase from the green alga Ankistrodesmus braunii.  

PubMed

Assimilatory nitrate reductase (NAD(P)H-nitrate oxidoreductase, EC 1.6.6.2) from the green alga Ankistrodesmus braunii can be purified to homogeneity by dye-ligand chromatography on blue-Sepharose. The purified enzyme, whose turnover number is 623 s-1, presents an optimum pH of 7.5 and Km values of 13 microM, 23 microM and 0.15 mM for NADH, NADPH and nitrate, respectively. The NADH-nitrate reductase activity exhibits an iso ping pong bi bi kinetic mechanism. The molecular weight of the native nitrate reductase is 467 400, while that of its subunits is 58 750. These values suggest an octameric structure for the enzyme, which has been confirmed by electron microscopy. As deduced from spectrophotometric and fluorimetric studies, the enzyme contains FAD and cytochrome b-557 as prosthetic groups. FAD is not covalently bound to the protein and is easily dissociated in diluted solutions from the enzyme. Its apparent Km value is 4 nM, indicative of a high affinity of the enzyme for FAD. The results of the quantitative analyses of prosthetic groups indicate that nitrate reductase contains four molecules of flavin, four heme irons, and two atoms of molybdenum. The three components act sequentially transferring electrons from reduced pyridine nucleotides to nitrate, thus forming a short electron transport chain along the protein. A mechanism is proposed for the redox interconversion of the nitrate reductase activity. Inactivation seems to occur by formation of a stable complex of reduced enzyme with cyanide or superoxide, while reactivation is a consequence of reoxidation of the inactive enzyme. Both reactions imply the transfer of only one electron. PMID:6682479

De la Rosa, M A

1983-01-01

115

How the green alga Chlamydomonas reinhardtii keeps time.  

PubMed

The unicellular green alga Chlamydomonas reinhardtii has two flagella and a primitive visual system, the eyespot apparatus, which allows the cell to phototax. About 40 years ago, it was shown that the circadian clock controls its phototactic movement. Since then, several circadian rhythms such as chemotaxis, cell division, UV sensitivity, adherence to glass, or starch metabolism have been characterized. The availability of its entire genome sequence along with homology studies and the analysis of several sub-proteomes render C. reinhardtii as an excellent eukaryotic model organism to study its circadian clock at different levels of organization. Previous studies point to several potential photoreceptors that may be involved in forwarding light information to entrain its clock. However, experimental data are still missing toward this end. In the past years, several components have been functionally characterized that are likely to be part of the oscillatory machinery of C. reinhardtii since alterations in their expression levels or insertional mutagenesis of the genes resulted in defects in phase, period, or amplitude of at least two independent measured rhythms. These include several RHYTHM OF CHLOROPLAST (ROC) proteins, a CONSTANS protein (CrCO) that is involved in parallel in photoperiodic control, as well as the two subunits of the circadian RNA-binding protein CHLAMY1. The latter is also tightly connected to circadian output processes. Several candidates including a significant number of ROCs, CrCO, and CASEIN KINASE1 whose alterations of expression affect the circadian clock have in parallel severe effects on the release of daughter cells, flagellar formation, and/or movement, indicating that these processes are interconnected in C. reinhardtii. The challenging task for the future will be to get insights into the clock network and to find out how the clock-related factors are functionally connected. In this respect, system biology approaches will certainly contribute in the future to improve our understanding of the C. reinhardtii clock machinery. PMID:20174954

Schulze, Thomas; Prager, Katja; Dathe, Hannes; Kelm, Juliane; Kiessling, Peter; Mittag, Maria

2010-08-01

116

Bioactive constituents from the green alga Caulerpa racemosa.  

PubMed

Three diterpenoids, including a pair of epimers, racemobutenolids A and B (1 and 2), and 4',5'-dehydrodiodictyonema A (3), an ?-tocopheroid, ?-tocoxylenoxy (8), and an 28-oxostigmastane steroid, (23E)-3?-hydroxy-stigmasta-5,23-dien-28-one (11), together with 12 known compounds, were isolated from the green alga Caulerpa racemosa. The structures of the new compounds were elucidated by detailed analysis of spectroscopic data, and by comparison with data for related known compounds. The epimers (1 and 2) are two unusual diterpenoid lactones bearing a ?-methyl-?-substituted butenolide moiety, and 3 and 8 represent the first naturally occurring natural products with a hematinic acid ester group and 3,5-dimethylphenoxy functionality, respectively. The enzyme inhibitory activities of the isolated compounds were evaluated in vitro against PTP1B and related PTPs (TCPTP, CDC25B, LAR, SHP-1, and SHP-2). Compounds 3, 5, 6, and 9-14 exhibited different levels of PTP1B inhibitory activities with IC50 values ranging from 2.30 to 50.02?M. Of these compounds, 3, 9, and 11 showed the most potent inhibitory activities towards PTP1B with IC50 values of 2.30, 3.85, and 3.80?M, respectively. More importantly, the potent PTP1B inhibitors 3, 9, and 11 also displayed high selectivity over the highly homologous TCPTP and other PTPs. Also, the neuroprotective effects of the isolates against A?25-35-induced cell damage in SH-SY5Y cells were investigated. Compounds 10, 11, and 14 exhibited significant neuroprotective effects against A?25-35-induced SH-SY5Y cell damage with 11.31-15.98% increases in cell viability at 10?M. In addition, the cytotoxic activities of the isolated compounds were tested against the human cancer cell lines A-549 and HL-60. PMID:25497963

Yang, Peng; Liu, Ding-Quan; Liang, Tong-Jun; Li, Jia; Zhang, Hai-Yan; Liu, Ai-Hong; Guo, Yue-Wei; Mao, Shui-Chun

2015-01-01

117

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. PMID:22655677

2012-01-01

118

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

119

Biosorption of malachite green, a cationic dye onto Pithophora sp., a fresh water algae  

Microsoft Academic Search

Batch sorption experiments were carried out for the removal of malachite green from its aqueous solution using Pithophora sp., a fresh water algae as biosorbent. Dye uptake was found to increase with contact time and initial malachite green concentration. Equilibrium uptake was found to be pH dependent and maximum uptake was observed at a pH of 6. The effect of

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

2006-01-01

120

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

121

Trails of green alga hydrogen research - from hans gaffron to new frontiers.  

PubMed

This paper summarizes aspects of the history of photosynthetic hydrogen research, from the pioneering discovery of Hans Gaffron over 60 years ago to the potential exploitation of green algae in commercial H(2)-production. The trail started as a mere scientific curiosity, but promises to be a most important discovery, one that leads photosynthesis research to important commercial applications. Progress achieved in the field of photosynthetic hydrogen production by green algae includes elucidation of the mechanism, the ability to modify photosynthesis by physiological means and to produce bulk amounts of H(2) gas, and cloning of the [Fe]-hydrogenase genes in several green algal species. PMID:16328836

Melis, Anastasios; Happe, Thomas

2004-01-01

122

Dasycladalean green algae and some problematic algae from the Upper Triassic of the Nayband Formation (northeast Iran)  

NASA Astrophysics Data System (ADS)

This paper describes the dasycladales green algae from two sections of the Rhaetian Howz-e Khan Member of the Nayband Formation, northwest of the Dig-e Rostam motorway service area (south of the type locality of the Formation near the town Naybandan). Both sections are composed of bedded fine-grained limestones containing partly abundant dasycladales algae associated with foraminifers, which are mainly aulotortid types. Additionally scattered samples were collected from several beds of the Howz-e Khan Member in this area. The following dasycladalean taxa are described: Chinianella carpatica (Bystrický), Griphoporella curvata (Gümbel), Griphoporella lutensis nov. sp., some undetermined dasycladacean taxa, problematic algae like Lithocodium aggregatum Elliott, Bacinella irregularis Radoicic, and Thaumatoporella parvovesiculifera (Raineri). While Chinianella carpatica is not numerous and the other described algae are rare, Griphoporella curvata is extremely abundant in the investigated material. This paper describes Ch. carpatica for the first time from the Triassic of Iran and also includes a discussion of the strong variability of G. curvata. Additionally we include an informal description of a problematic fossil (animal: shell fragment?; plant: alga?).

Senowbari-Daryan, Baba; Rashidi, Koorosh; Saberzadeh, Behnam

2011-12-01

123

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

124

Effect of culture medium on hydrogen production by sulfur-deprived marine green algae Platymonas subcordiformis  

Microsoft Academic Search

To study the effect of culture medium on hydrogen production by the marine green algae, Platymonas subcordiformis under sulfur deprivation, cell growth, hydrogen production, and starch and protein catabolism was investigated in the work.\\u000a Algae cells cultured only in optimized medium required 6?8 days to reach the late logarithmic at the approximate density of\\u000a (2.00 ± 0.18) × 106 cells\\/mL,

Chunqiu Ran; Fengjie Zhang; Hongjie Sun; Budiao Zhao

2009-01-01

125

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

126

Optimization of Recombinant Protein Expression in the Chloroplasts of Green Algae  

Microsoft Academic Search

Through advances in molecular and genetic techniques, protein expression in the chloroplasts of green algae has been optimized\\u000a for high-level expression. Recombinant proteins expressed in algae have the potential to provide novel and safe treatment\\u000a of disease and infection where current, high-cost drugs are the only option, or worse, where therapeutic drugs are not available\\u000a due to their prohibitively high-cost

Samuel P. Fletcher; Machiko Muto; Stephen P. Mayfield

127

Bioelectricity generation and microcystins removal in a blue-green algae powered microbial fuel cell.  

PubMed

Bioelectricity production from blue-green algae was examined in a single chamber tubular microbial fuel cell (MFC). The blue-green algae powered MFC produced a maximum power density of 11 4 mW/m(2) at a current density of 0.55 mA/m(2). Coupled with the bioenergy generation, high removal efficiencies of chemical oxygen demand (COD) and nitrogen were also achieved in MFCs. Over 78.9% of total chemical oxygen demand (TCOD), 80.0% of soluble chemical oxygen demand (SCOD), 91.0% of total nitrogen (total-N) and 96.8% ammonium-nitrogen (NH(3)-N) were removed under closed circuit conditions in 12 days, which were much more effective than those under open circuit and anaerobic reactor conditions. Most importantly, the MFC showed great ability to remove microcystins released from blue-green algae. Over 90.7% of MC-RR and 91.1% of MC-LR were removed under closed circuit conditions (500?). This study showed that the MFC could provide a potential means for electricity production from blue-green algae coupling algae toxins removal. PMID:21295401

Yuan, Yong; Chen, Qing; Zhou, Shungui; Zhuang, Li; Hu, Pei

2011-03-15

128

Green algae in alpine biological soil crust communities: acclimation strategies against ultraviolet radiation and dehydration.  

PubMed

Green algae are major components of biological soil crusts in alpine habitats. Together with cyanobacteria, fungi and lichens, green algae form a pioneer community important for the organisms that will succeed them. In their high altitudinal habitat these algae are exposed to harsh and strongly fluctuating environmental conditions, mainly intense irradiation, including ultraviolet radiation, and lack of water leading to desiccation. Therefore, green algae surviving in these environments must have evolved with either avoidance or protective strategies, as well as repair mechanisms for damage. In this review we have highlighted these mechanisms, which include photoprotection, photochemical quenching, and high osmotic values to avoid water loss, and in some groups flexibility of secondary cell walls to maintain turgor pressure even in water-limited situations. These highly specialized green algae will serve as good model organisms to study desiccation tolerance or photoprotective mechanisms, due to their natural capacity to withstand unfavorable conditions. We point out the urgent need for modern phylogenetic approaches in characterizing these organisms, and molecular methods for analyzing the metabolic changes involved in their adaptive strategies. PMID:24954980

Karsten, Ulf; Holzinger, Andreas

2014-01-01

129

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

130

Antioxidant Enzyme Activities in the Cyanobacteria Planktothrix Agardhii, Planktothrix Perornata, Raphidiopsis Brookii, and the Green Alga Selenastrum Capricornutum  

Technology Transfer Automated Retrieval System (TEKTRAN)

Previous studies have demonstrated that compounds generating reactive oxygen species (ROS) are selectively toxic towards certain species of cyanobacteria (blue-green algae) when compared to green algae (e.g., Selenastrum capricornutum). The antioxidant enzyme activities of S. capricornutum and seve...

131

Modeling the Role of Zebra Mussels in the Proliferation of Blue-green Algae in Saginaw Bay, Lake Huron  

EPA Science Inventory

Under model assumptions from Saginaw Bay 1991, selective rejection of blue-green algae by zebra mussels appears to be a necessary factor in the enhancement of blue-green algae production in the presence of zebra mussels. Enhancement also appears to depend on the increased sedime...

132

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

133

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

134

Uptake and Retention of Cs137 by a Blue-Green Alga in Continuous Flow and Batch Culture Systems  

SciTech Connect

Since routine monitoring data show that blue-green algae concentrate radioactivity from water by factors as great as 10,000, this study was initiated to investigate the uptake and retention patterns of specific radionuclides by the dominant genera of blue-green algae in the reactor effluents. Plectonema purpureum was selected for this study.

Watts, J.R.

2003-02-18

135

Uptake and Retention of Cs137 by a Blue-Green Alga in Continuous Flow and Batch Culture Systems  

Microsoft Academic Search

Since routine monitoring data show that blue-green algae concentrate radioactivity from water by factors as great as 10,000, this study was initiated to investigate the uptake and retention patterns of specific radionuclides by the dominant genera of blue-green algae in the reactor effluents. Plectonema purpureum was selected for this study.

2003-01-01

136

Metabolism of glucose by unicellular blue-green algae  

Microsoft Academic Search

A facultative photo- and chemoheterotroph, the unicellular bluegreen alga Aphanocapsa 6714, dissimilates glucose with formation of CO2 as the only major product. A substantial fraction of the glucose consumed is assimilated and stored as polyglucose (probably glycogen). The oxidation of glucose proceeds through the pentose phosphate pathway. The first enzyme of this pathway, glucose-6-phosphate dehydrogenase, is partly inducible. In addition,

R. A. Pelroy; R. Rippka; R. Y. Stanier

1972-01-01

137

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 ...

138

Differential sensitivity of two green algae, Scenedesmus obliqnus and Chlorella pyrenoidosa, to 12 pesticides.  

PubMed

Growth-inhibiting tests were carried out for 12 pesticides (including 11 fungicides: fosetyl-aluminum, benomyl, metalaxyl, iprodione, dimetachlone, carbendazim, thiophanate-methyl, bismerthiazol, procymidone, zineb, chlorothalonil, and the acaricide abamectin) in the green algae Chlorella pyrenoidosa and Scenedesmus obliqnus and the differential sensitivities of the two green algae to those pesticides were compared. The results indicate that the acute toxicity of benomyl to C. pyrenoidosa and S. obliqnus is the highest among all of the pesticides tested and is close to that of the photosynthesis-inhibiting herbicides atrazine, simazine, and chlorotoluron. Meanwhile, algal species vary widely in their response to the pesticides. The results demonstrated that there was a differential response to various pesticides by the two species of algae and that the sensitivity of various species of algae exposed to chlorothalonil varied by nearly two orders of magnitude; sensitivity to thiophanate-methyl varied by more than one order. Investigations using different algal species as test organisms have demonstrated that algae vary greatly in their response to chemicals. Differential sensitivity of green species to the compounds could induce species shifts within communities. PMID:12051808

Ma, Jianyi; Zheng, Rongquan; Xu, Ligen; Wang, Shufeng

2002-05-01

139

Genome-wide analysis of tandem repeats in plants and green algae.  

PubMed

Tandem repeats (TRs) extensively exist in the genomes of prokaryotes and eukaryotes. Based on the sequenced genomes and gene annotations of 31 plant and algal species in Phytozome version 8.0 (http://www.phytozome.net/), we examined TRs in a genome-wide scale, characterized their distributions and motif features, and explored their putative biological functions. Among the 31 species, no significant correlation was detected between the TR density and genome size. Interestingly, green alga Chlamydomonas reinhardtii (42,059 bp/Mbp) and castor bean Ricinus communis (55,454 bp/Mbp) showed much higher TR densities than all other species (13,209 bp/Mbp on average). In the 29 land plants, including 22 dicots, 5 monocots, and 2 bryophytes, 5'-UTR and upstream intergenic 200-nt (UI200) regions had the first and second highest TR densities, whereas in the two green algae (C. reinhardtii and Volvox carteri) the first and second highest densities were found in intron and coding sequence (CDS) regions, respectively. In CDS regions, trinucleotide and hexanucleotide motifs were those most frequently represented in all species. In intron regions, especially in the two green algae, significantly more TRs were detected near the intron-exon junctions. Within intergenic regions in dicots and monocots, more TRs were found near both the 5' and 3' ends of genes. GO annotation in two green algae revealed that the genes with TRs in introns are significantly involved in transcriptional and translational processing. As the first systematic examination of TRs in plant and green algal genomes, our study showed that TRs displayed nonrandom distribution for both intragenic and intergenic regions, suggesting that they have potential roles in transcriptional or translational regulation in plants and green algae. PMID:24192840

Zhao, Zhixin; Guo, Cheng; Sutharzan, Sreeskandarajan; Li, Pei; Echt, Craig S; Zhang, Jie; Liang, Chun

2014-01-01

140

Genome-Wide Analysis of Tandem Repeats in Plants and Green Algae  

PubMed Central

Tandem repeats (TRs) extensively exist in the genomes of prokaryotes and eukaryotes. Based on the sequenced genomes and gene annotations of 31 plant and algal species in Phytozome version 8.0 (http://www.phytozome.net/), we examined TRs in a genome-wide scale, characterized their distributions and motif features, and explored their putative biological functions. Among the 31 species, no significant correlation was detected between the TR density and genome size. Interestingly, green alga Chlamydomonas reinhardtii (42,059 bp/Mbp) and castor bean Ricinus communis (55,454 bp/Mbp) showed much higher TR densities than all other species (13,209 bp/Mbp on average). In the 29 land plants, including 22 dicots, 5 monocots, and 2 bryophytes, 5?-UTR and upstream intergenic 200-nt (UI200) regions had the first and second highest TR densities, whereas in the two green algae (C. reinhardtii and Volvox carteri) the first and second highest densities were found in intron and coding sequence (CDS) regions, respectively. In CDS regions, trinucleotide and hexanucleotide motifs were those most frequently represented in all species. In intron regions, especially in the two green algae, significantly more TRs were detected near the intron–exon junctions. Within intergenic regions in dicots and monocots, more TRs were found near both the 5? and 3? ends of genes. GO annotation in two green algae revealed that the genes with TRs in introns are significantly involved in transcriptional and translational processing. As the first systematic examination of TRs in plant and green algal genomes, our study showed that TRs displayed nonrandom distribution for both intragenic and intergenic regions, suggesting that they have potential roles in transcriptional or translational regulation in plants and green algae. PMID:24192840

Zhao, Zhixin; Guo, Cheng; Sutharzan, Sreeskandarajan; Li, Pei; Echt, Craig S.; Zhang, Jie; Liang, Chun

2013-01-01

141

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. PMID:23986769

Holzinger, Andreas; Karsten, Ulf

2013-01-01

142

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

PubMed

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. PMID:23986769

Holzinger, Andreas; Karsten, Ulf

2013-01-01

143

Grazing on green algae by the periwinkle Littorina littorea in the Wadden Sea  

Microsoft Academic Search

On sedimentary tidal flats in the Wadden Sea near the Island of Sylt, the periwinkleLittorina littorea occurred preferentially on clusters and beds of mussels and on shell beds (100 to 350 m?2), achieved moderate densities on green algal patches or mats (20 to 50 m?2), and remained rare on bare sediments (?2). Green algae covering>10% of sediment surface appeared in

U. Wilhelmsen; K. Reise

1994-01-01

144

Solar energy conversion with hydrogen-producing cultures of the blue-green alga, Anabaena cylindrica  

Microsoft Academic Search

It was demonstrated that a catalytic, sustained production of hydrogen from water can be carried out under outdoor conditions using a simple glass converter and a stationary blue-green algal culture. This process meets the basic technical requirements of biophotolysis. Improvement in rates of hydrogen production by this system could be achieved by selecting wild-type blue-green algae better suited to hydrogen

P. C. Hallenbeck; L. V. Kochian; J. C. Weissman; J. R. Benemann

1978-01-01

145

Harvesting green algae from eutrophic reservoir by electroflocculation and post-use for biodiesel production.  

PubMed

Each year there are more frequent blooms of green algae and cyanobacteria, representing a serious environmental problem of eutrophication. Electroflocculation (EF) was studied to harvest the algae which are present in reservoirs, as well as different factors which may influence on the effectiveness of the process: the voltage applied to the culture medium, run times, electrodes separation and natural sedimentation. Finally, the viability of its use to obtain biodiesel was studied by direct transesterification. The EF process carried out at 10V for 1min, with an electrode separation of 5.5cm and a height of 4cm in culture vessel, obtained a recovery efficiency greater than 95%, and octadecenoic and palmitic acids were obtained as the fatty acid methyl esters (FAMEs). EF is an effective method to harvest green algae during the blooms, obtaining the greatest amount of biomass for subsequent use as a source of biodiesel. PMID:25863202

Valero, Enrique; Álvarez, Xana; Cancela, Ángeles; Sánchez, Ángel

2015-07-01

146

What is Ostreococcus tauri? Ostreococcus tauri is a unicellular green algae that was discovered in the Mediterranean Thau lagoon (France) in 1994. With a size less than  

E-print Network

What is Ostreococcus tauri? Ostreococcus tauri is a unicellular green algae that was discovered, compared to other green algae. Apart from this simple cellular structure, the genome size of Ostreococcus2/M transition. Here, the first green lineage Cdc25 ortholog is described in the unicellular alga

Gent, Universiteit

147

The xanthophyll cycle in green algae (chlorophyta): its role in the photosynthetic apparatus.  

PubMed

Light-dependent conversion of violaxanthin to zeaxanthin, the so-called xanthophyll cycle, was shown to serve as a major, short-term light acclimation mechanism in higher plants. The role of xanthophylls in thermal dissipation of surplus excitation energy was deduced from the linear relationship between zeaxanthin formation and the magnitude of non-photochemical quenching. Unlike in higher plants, the role of the xanthophyll cycle in green algae (Chlorophyta) is ambiguous, since its contribution to energy dissipation can significantly vary among species. Here, we have studied the role of the xanthophyll cycle in the adaptation of several species of green algae (Chlorella, Scenedesmus, Haematococcus, Chlorococcum, Spongiochloris) to high irradiance. The xanthophyll cycle has been found functional in all tested organisms; however its contribution to non-photochemical quenching is not as significant as in higher plants. This conclusion is supported by three facts: (i) in green algae the content of zeaxanthin normalized per chlorophyll was significantly lower than that reported from higher plants, (ii) antheraxanthin + zeaxanthin content displayed different diel kinetics from NPQ and (iii) in green algae there was no such linear relationship between NPQ and Ax + Zx, as found in higher plants. We assume that microalgae rely on other dissipation mechanism(s), which operate along with xanthophyll cycle-dependent quenching. PMID:15143443

Masojídek, J; Kopecký, J; Koblízek, M; Torzillo, G

2004-05-01

148

Original article Fermentation of green alga sea-lettuce (Ulva sp)  

E-print Network

Original article Fermentation of green alga sea-lettuce (Ulva sp) and metabolism of its sulphate). The purpose of this study was to assess the fermentation characteristics and sulphate metabolism of Ulva and ulvan by human faecal bacteria fermentation system using a semi-continu- ous fermenter. Ulva and ulvan

Paris-Sud XI, Université de

149

Effect of Plasmolysis on the Rate of Respiration of a Green Alga  

Microsoft Academic Search

IN some recent experiments to be reported more fully elsewhere, the effect of plasmolysis and of temperature on the rate of respiration of the green alga Scenedesmus quadricauda has been investigated. The results may be summarized as follows: (1) At 25° C. there is a highly significant (probability 0.1 per cent or less) decrease in the rate of respiration on

F. J. Taylor

1958-01-01

150

Multiple Metabolic Roles for the Nonphotosynthetic Plastid of the Green Alga Prototheca wickerhamii  

Microsoft Academic Search

The presence of plastids in diverse eukaryotic lineages that have lost the capacity for photosynthesis is well documented. The metabolic functions of such organelles, however, are poorly understood except in the case of the apicoplast in the Apicomplexa, a group of intracellular parasites including Plasmodium falciparum, and the plastid of the green alga Helicosporidium sp., a parasite for which the

Tudor Borza; Cristina E. Popescu; Robert W. Lee

2005-01-01

151

GUIDE TO THE IDENTIFICATION, ENVIRONMENTAL REQUIREMENTS AND POLLUTION TOLERANCE OF FRESHWATER BLUE-GREEN ALGAE (CYANOPHYTA)  

EPA Science Inventory

An illustrated key to 42 genera and 161 species of Blue-green algae is provided. Information on the environmental requirements and pollution tolerance of these species was compiled from 430 references and summarized on profile sheets. It is suggested that this information be empl...

152

Final technical report [Molecular genetic analysis of biophotolytic hydrogen production in green algae  

SciTech Connect

The principal objective of this project was to identify genes necessary for biophotolytic hydrogen production in green algae, using Chlamydomonas reinhardtii as an experimental organism. The main strategy was to isolate mutants that are selectively deficient in hydrogen production and to genetically map, physically isolate, and ultimately sequence the affected genes.

Mets, Laurens

2000-12-31

153

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

154

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

155

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

156

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 ...

157

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

158

Development of a Nuclear Transformation System for Oleaginous Green Alga Lobosphaera (Parietochloris)  

E-print Network

acids (PUFA). The unicellular green alga Lobosphaera (Parietochloris) incisa is an outstanding candidate for the efficient phototrophic production of arachidonic acid (AA), an essential v-6 PUFA for infant brain a platform for the successful genetic engineering of L. incisa and its long-chain PUFA metabolism. Citation

159

The microtubule cytoskeleton in developing cysts of the green alga Acetabularia : Involvement in cell wall differentiation  

Microsoft Academic Search

Summary Cysts of the green algaAcetabularia develop a unique lid structure to enable the release of gametes. This lid is separated from the rest of the thick cellulose cell wall by a circular fault line formed within the fibrillar texture of the wall. By immunofluorescence microscopy, we show that, prior to the first division of the single cyst nucleus, the

D. Menzel; Christine Elsner-Menzel

1990-01-01

160

Green algae associated with the granite walls of monuments in Galicia (NW Spain)  

Microsoft Academic Search

This paper presents the results of a study carried out on the diversity of the green algae (Chlorophyta sensu lato) colonizing the granite walls of buildings having heritage value in Galicia (NW Spain) and their effect on the substrate. The material was collected by scraping the walls under aseptic conditions. It was then cultured under constant conditions of light, temperature

Ana Rifón-Lastra; Ángela Noguerol-Seoane

2001-01-01

161

Gametic behavior in a marine green alga, Monostroma angicava : an effect of phototaxis on mating efficiency  

Microsoft Academic Search

.   The role of phototactic behavior of gametes was tested experimentally in the slightly anisogamous marine green alga Monostroma angicava Kjellman, and the effect of phototaxis on mating efficiency was discovered. Both male and female gametes showed positive\\u000a phototaxis in response to a white light source. In contrast, they did not respond to a red light source. Their swimming velocity

Tatsuya Togashi; Taizo Motomura; Terunobu Ichimura; Paul Alan Cox

1999-01-01

162

Removal of toxic chromium from wastewater using green alga Ulva lactuca and its activated carbon  

Microsoft Academic Search

Biosorption of heavy metals can be an effective process for the removal of toxic chromium ions from wastewater. In this study, the batch removal of toxic hexavalent chromium ions from aqueous solution, saline water and wastewater using marine dried green alga Ulva lactuca was investigated. Activated carbon prepared from U. lactuca by acid decomposition was also used for the removal

Amany El-Sikaily; Ahmed El Nemr; Azza Khaled; Ola Abdelwehab

2007-01-01

163

Development of suitable photobioreactors for CO 2 sequestration addressing global warming using green algae and cyanobacteria  

Microsoft Academic Search

CO2 sequestration by cyanobacteria and green algae are receiving increased attention in alleviating the impact of increasing CO2 in the atmosphere. They, in addition to CO2 capture, can produce renewable energy carriers such as carbon free energy hydrogen, bioethanol, biodiesel and other valuable biomolecules. Biological fixation of CO2 are greatly affected by the characteristics of the microbial strains, their tolerance

Kanhaiya Kumar; Chitralekha Nag Dasgupta; Bikram Nayak; Peter Lindblad; Debabrata Das

2011-01-01

164

Phycobilisomes from blue-green and red algae: isolation criteria and dissociation characteristics  

Microsoft Academic Search

A general procedure for the isolation of functionally intact phycobilisomes was devised, based on modifications of previously used procedures. It has been successful with numerous species of red and blue-green algae (Anabaena variabilis, Anacystis nidulans, Agmenellum quadruplicatum, Fremyella diplosiphon, Glaucosphaera vacuolata, Griffithsia pacifica, Nemalion multifidum, Nostoc sp., Phormidium persicinum, Porphyridium cruentum, P. sordidum, P. aerugineum, Rhodosorus marinus). Isolation was carried

E. Gantt; C. A. Lipschultz; J. Grabowski; B. K. Zimmerman

1979-01-01

165

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. PMID:23960716

El Gamal, Ali A.

2009-01-01

166

Oleosin of Subcellular Lipid Droplets Evolved in Green Algae1[W][OA  

PubMed Central

In primitive and higher plants, intracellular storage lipid droplets (LDs) of triacylglycerols are stabilized with a surface layer of phospholipids and oleosin. In chlorophytes (green algae), a protein termed major lipid-droplet protein (MLDP) rather than oleosin on LDs was recently reported. We explored whether MLDP was present directly on algal LDs and whether algae had oleosin genes and oleosins. Immunofluorescence microscopy revealed that MLDP in the chlorophyte Chlamydomonas reinhardtii was associated with endoplasmic reticulum subdomains adjacent to but not directly on LDs. In C. reinhardtii, low levels of a transcript encoding an oleosin-like protein (oleolike) in zygotes-tetrads and a transcript encoding oleosin in vegetative cells transferred to an acetate-enriched medium were found in transcriptomes and by reverse transcription-polymerase chain reaction. The C. reinhardtii LD fraction contained minimal proteins with no detectable oleolike or oleosin. Several charophytes (advanced green algae) possessed low levels of transcripts encoding oleosin but not oleolike. In the charophyte Spirogyra grevilleana, levels of oleosin transcripts increased greatly in cells undergoing conjugation for zygote formation, and the LD fraction from these cells contained minimal proteins, two of which were oleosins identified via proteomics. Because the minimal oleolike and oleosins in algae were difficult to detect, we tested their subcellular locations in Physcomitrella patens transformed with the respective algal genes tagged with a Green Fluorescent Protein gene and localized the algal proteins on P. patens LDs. Overall, oleosin genes having weak and cell/development-specific expression were present in green algae. We present a hypothesis for the evolution of oleosins from algae to plants. PMID:23391579

Huang, Nan-Lan; Huang, Ming-Der; Chen, Tung-Ling L.; Huang, Anthony H.C.

2013-01-01

167

Grazing on green algae by the periwinkle Littorina littorea in the Wadden Sea  

NASA Astrophysics Data System (ADS)

On sedimentary tidal flats in the Wadden Sea near the Island of Sylt, the periwinkle Littorina littorea occurred preferentially on clusters and beds of mussels and on shell beds (100 to 350 m-2), achieved moderate densities on green algal patches or mats (20 to 50 m-2), and remained rare on bare sediments (<5 m-2). Green algae covering>10% of sediment surface appeared in summer on approximately one third of the tidal zone, mainly in the upper and sheltered parts and almost never on mussel and shell beds. In feeding experiments, L. littorea ingested more of the dominant alge, Enteromorpha, than of Ulva, irrespective of whether or not algae were fresh or decaying. The tough thalli of Chaetomorpha were hardly consumed. Snails feeding on Enteromorpha produced fecal pellets from which new growth of Enteromorpha started. In the absence of periwinkles, Enteromorpha developed on mussels and the attached fucoids. Experimentally increased snail densities on sediments prevented green algal development, but the snails were unable to graze down established algal mats. It is concluded that natural densities of L. littorea hardly affect the ephemeral mass development of green algae on sediments. However, where the snails occur at high densities, i.e. on mussel beds, green algal development may be prevented.

Wilhelmsen, U.; Reise, K.

1994-06-01

168

Endosymbiotic alga from green hydra under the influence of cinoxacin.  

PubMed

Cinoxacin (Cxn) showed a strong effect on the endosymbiotic alga Chlorella; it was significantly damaged. Changes in algal color, position, structure and ultrastructure were found. In some algal cells ultrastructures were completely destroyed. The antichloroplastal and antimitochondrial effect was especially expressed. Damage to the thylakoid system of chloroplasts was more pronounced with increasing Cxn concentration. Some of the mitochondria were swollen and some of them were completely destroyed. From the evolutionary point of view, the correlation between antibacterial, and antichloroplastal and antimitochondrial effect of Cxn points to the evolutionary connection of chloroplasts and mitochondria with eubacteria. PMID:16295658

Kovacevi?, G; Kalafati?, M; Ljubesi?, N

2005-01-01

169

Strategies of response to copper, cadmium, and lead by a blue-green and a green alga.  

PubMed

The toxic metal ions Cu2+, Cd2+, and Pb2+ inhibited growth of the green alga Ankistrodesmus braunii and the blue-green alga (Cyanobacterium) Anabaena, strain 7120. Some concentrations of Cu lysed Anabaena 7120 at early, but not late, stages of growth. The other metals inhibited growth without causing lysis. Adding the chelating agent nitrilotriacetic acid (NTA) did not reduce, and in some cases increased, metal toxicity to Anabaena 7120. This suggests that these metals do not act on this alga only in the ionic form. When Anabaena 7120 grew in a sublethal concentrations of Cu(NO3)2 (10(-5)M) most of the Cu was found outside the cell, in nonionic form. About half the Cd was found to be cell associated when these algae grew in the presence of 10(-5)M Cd(NO3)2. Ankistrodesmus braunii bound substantial amounts of both Cd and Cu when growing in their presence. At certain Cu levels, the amount bound per cell remained virtually constant during growth. In Cd, the amount bound per cell was highest at the beginning of growth and then fell. Cell-associated metals were found in both wall plus membrane and cytoplasmic fractions of A. braunii after mechanical lysis. When these algae grew over dialysis sacs containing sediment loaded with Cd or Cu, substantial amounts of these metals left the sediment and entered the algal cultures. They were found both cell associated and in the culture medium of A. braunii. In cultures of Anabaena 7120, Cd removed from the sediment was found in both cells and culture medium, but Cu was found almost entirely in the culture medium. The effects that bloom of such algae might have on the mobilization of these metals from sediments in natural waters are discussed. PMID:6783279

Laube, V M; McKenzie, C N; Kushner, D J

1980-11-01

170

Origin of land plants: Do conjugating green algae hold the key?  

PubMed Central

Background The terrestrial habitat was colonized by the ancestors of modern land plants about 500 to 470 million years ago. Today it is widely accepted that land plants (embryophytes) evolved from streptophyte algae, also referred to as charophycean algae. The streptophyte algae are a paraphyletic group of green algae, ranging from unicellular flagellates to morphologically complex forms such as the stoneworts (Charales). For a better understanding of the evolution of land plants, it is of prime importance to identify the streptophyte algae that are the sister-group to the embryophytes. The Charales, the Coleochaetales or more recently the Zygnematales have been considered to be the sister group of the embryophytes However, despite many years of phylogenetic studies, this question has not been resolved and remains controversial. Results Here, we use a large data set of nuclear-encoded genes (129 proteins) from 40 green plant taxa (Viridiplantae) including 21 embryophytes and six streptophyte algae, representing all major streptophyte algal lineages, to investigate the phylogenetic relationships of streptophyte algae and embryophytes. Our phylogenetic analyses indicate that either the Zygnematales or a clade consisting of the Zygnematales and the Coleochaetales are the sister group to embryophytes. Conclusions Our analyses support the notion that the Charales are not the closest living relatives of embryophytes. Instead, the Zygnematales or a clade consisting of Zygnematales and Coleochaetales are most likely the sister group of embryophytes. Although this result is in agreement with a previously published phylogenetic study of chloroplast genomes, additional data are needed to confirm this conclusion. A Zygnematales/embryophyte sister group relationship has important implications for early land plant evolution. If substantiated, it should allow us to address important questions regarding the primary adaptations of viridiplants during the conquest of land. Clearly, the biology of the Zygnematales will receive renewed interest in the future. PMID:21501468

2011-01-01

171

Relationship between water solubility of chlorobenzenes and their effects on a freshwater green alga  

SciTech Connect

The effective concentrations of benzene and 12 chlorobenzenes that reduced 50% of the primary productivity (EC/sub 50/) of a freshwater green alga, Ankistrodesmus falcatus, were determined. Benzene was the least toxic chemical and the toxicity increased as the degree of chlorine substitution in the aromatic ring increased. No EC/sub 50/ value could be obtained for HCB. A quantitative relationship was found to exist between water solubility, lipophilicity and the EC/sub 50/. A good correlation was also observed between the EC/sub 50/ for this alga and other toxicity data for various aquatic biota.

Wong, P.T.S.; Chau, Y.K.; Rhamey, J.S.; Docker, M.

1984-01-01

172

Chemical composition, protein digestibility and heat of combustion of filamentous green algae  

Microsoft Academic Search

The filamentous green algae investigated (Hormidium sp. strainHindák 1963\\/21,Ulothrix sp. strainHindák 1964\\/2,Uronema gigas\\u000a Visch. strainVischer\\/Bloom. 174,Uronema sp. strainHindák 1963\\/25 andStigeoclonium sp. strainHindák 1964\\/1), contain similar amounts of proteins, lipids, cellulose and ash as the hitherto used production strains of the generaChlorella andScenedesmus. The digestibility of proteins in vitro is about one-third higher in the filamentous algae than in the employed

F. Hindák; S. P?ibil

1968-01-01

173

[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

174

The complete mitochondrial DNA sequences of Nephroselmis olivacea and Pedinomonas minor. Two radically different evolutionary patterns within green algae.  

PubMed Central

Green plants appear to comprise two sister lineages, Chlorophyta (classes Chlorophyceae, Ulvophyceae, Trebouxiophyceae, 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 Prasinophyceae. This class is thought to include descendants of the earliest diverging green algae. We find that Nephroselmis and Pedinomonas mtDNAs differ markedly in size, gene content, and gene organization. Of the green algal mtDNAs sequenced so far, that of Nephroselmis (45,223 bp) is the most ancestral (minimally diverged) and occupies the phylogenetically most basal position within the Chlorophyta. Its repertoire of 69 genes closely resembles that in the mtDNA of Prototheca wickerhamii, a later diverging trebouxiophycean green alga. Three of the Nephroselmis genes (nad10, rpl14, and rnpB) have not been identified in previously sequenced mtDNAs of green algae and land plants. In contrast, the 25,137-bp Pedinomonas mtDNA contains only 22 genes and retains few recognizably ancestral features. In several respects, including gene content and rate of sequence divergence, Pedinomonas mtDNA resembles the reduced mtDNAs of chlamydomonad algae, with which it is robustly affiliated in phylogenetic analyses. Our results confirm the existence of two radically different patterns of mitochondrial genome evolution within the green algae. PMID:10488238

Turmel, M; Lemieux, C; Burger, G; Lang, B F; Otis, C; Plante, I; Gray, M W

1999-01-01

175

Regulation of Chlorophyll Synthesis in the Green Alga Golenkinia  

PubMed Central

Chlorophyll synthesis in Golenkinia is inhibited 10-fold by growth in darkness on acetate or by growth on elevated concentrations of acetate in the light, particularly if the growth medium contains low levels of nitrogen. Glucose has no such inhibitory effect. ?-Aminolevulinic acid, with a maximal effect at 0.01 m, but not its precursors, overrides the inhibitory effect of acetate and darkness, restoring chlorophyll synthesis. Glycine, succinate, and ?-ketoglutarate, the precursors tested, all enter the cell. Cells forming chlorophyll produce significantly more aminolevulinic acid than do cells becoming bleached, further indicating the important regulatory role of this compound. Cyclic AMP has no effect on chlorophyll synthesis. These results are compared with those obtained studying other algae, and a mechanism relating light and acetate to chlorophyll formation is proposed. PMID:16659169

Ellis, Richard; Spooner, Ted; Yakulis, Robert

1975-01-01

176

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

177

MACROALGAL VOLUME: A SURROGATE FOR BIOMASS IN SOME GREEN ALGAE  

EPA Science Inventory

Two green algal morphotypes, filamentous species (e.g., Chaetomorpha spp.) and flattened or tubular (e.g.,Ulva spp. and Enteromorpha spp.) were collected from 63 sites within the Yaquina Bay estuary (Newport, OR) and used to compare an in situ volumetric biomass estimator to the...

178

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

179

DELAYED LIGHT PRODUCTION BY BLUE-GREEN ALGAE, RED ALGAE, AND PURPLE BACTERIA*  

E-print Network

Green plants have been shown to emit light for some seconds after they have been illuminated. The action spectrum for the production of the delayed light has been shown to be the same as the action spectrum for photosynthesis (1). The emission spectrum for the delayed light has been shown to be the

B William Arnold; Jane Thompson

180

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

181

Evaluation of Factors Promoting Astaxanthin Production by a Unicellular Green Alga, Haematococcus pluvialis, with Fractional Factorial Design  

Microsoft Academic Search

Factors affecting the astaxanthin production by a unicellular green alga, Haemato- coccus pluvialis UTEX 16, were evaluated with sequential fractional factorial design. To simulate an actual production mode, a two-stage process was adapted for astaxanthin production: the alga was first cultivated under vegetative growth conditions, and then astaxanthin production was induced by applying various induction methods. A high dose of

Y. E. Choi; Y.-S. Yun; J. M. Park

2002-01-01

182

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. PMID:8755544

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

1996-01-01

183

ULTRASTRUCTURE OF MITOSIS AND CYTOKINESIS IN THE MULTINUCLEATE GREEN ALGA ACROSIPHONIA  

PubMed Central

The processes of mitosis and cytokinesis in the multinucleate green alga Acrosiphonia have been examined in the light and electron microscopes. The course of events in division includes thickening of the chloroplast and migration of numerous nuclei and other cytoplasmic incusions to form a band in which mitosis occurs, while other nuclei in the same cell but not in the band do not divide. Centrioles and microtubules are associated with migrated and dividing nuclei but not with nonmigrated, nondividing nuclei. Cytokinesis is accomplished in the region of the band, by means of an annular furrow which is preceded by a hoop of microtubules. No other microtubules are associated with the furrow. Characteristics of nuclear and cell division in Acrosiphonia are compared with those of other multinucleate cells and with those of other green algae. PMID:4139161

Hudson, Peggy R.; Waaland, J. Robert

1974-01-01

184

Feedback Regulation of Arginine Biosynthesis in Blue-Green Algae and Photosynthetic Bacteria  

PubMed Central

Hoare, D. S. (The University of Texas, Austin), and S. L. Hoare. Feedback regulation of arginine biosynthesis in blue-green algae and photosynthetic bacteria. J. Bacteriol. 92:375–379. 1966.—A number of blue-green algae and photosynthetic bacteria synthesize arginine from glutamate via acetylated intermediates. Cell-free extracts of these photosynthetic microorganisms contain an N-acetyl glutamate phosphokinase, which is specifically inhibited by arginine. They also contain a transacetylase which forms ornithine from ?N-acetyl ornithine and glutamate. The transacetylase appears to be specific for l-glutamate. Arginine synthesis and its regulation by feedback inhibition in photosynthetic microorganisms differ from that in Escherichia coli and other Enterobacteriaceae. PMID:16562123

Hoare, D. S.; Hoare, S. L.

1966-01-01

185

A green algae mixture of scenedesmus and schroederiella attenuates obesity-linked metabolic syndrome in rats.  

PubMed

This study investigated the responses to a green algae mixture of Scenedesmus dimorphus and Schroederiella apiculata (SC) containing protein (46.1% of dry algae), insoluble fibre (19.6% of dry algae), minerals (3.7% of dry algae) and omega-3 fatty acids (2.8% of dry algae) as a dietary intervention in a high carbohydrate, high fat diet-induced metabolic syndrome model in four groups of male Wistar rats. Two groups were fed with a corn starch diet containing 68% carbohydrates as polysaccharides, while the other two groups were fed a diet high in simple carbohydrates (fructose and sucrose in food, 25% fructose in drinking water, total 68%) and fats (saturated and trans fats from beef tallow, total 24%). High carbohydrate, high fat-fed rats showed visceral obesity with hypertension, insulin resistance, cardiovascular remodelling, and nonalcoholic fatty liver disease. SC supplementation (5% of food) lowered total body and abdominal fat mass, increased lean mass, and attenuated hypertension, impaired glucose and insulin tolerance, endothelial dysfunction, infiltration of inflammatory cells into heart and liver, fibrosis, increased cardiac stiffness, and nonalcoholic fatty liver disease in the high carbohydrate, high fat diet-fed rats. This study suggests that the insoluble fibre or protein in SC helps reverse diet-induced metabolic syndrome. PMID:25875119

Kumar, Senthil Arun; Magnusson, Marie; Ward, Leigh C; Paul, Nicholas A; Brown, Lindsay

2015-01-01

186

The influence of elastic modulus and thickness on the release of the soft-fouling green alga Ulva linza (syn. Enteromorpha linza) from  

E-print Network

The influence of elastic modulus and thickness on the release of the soft-fouling green alga Ulva fouling alga Ulva (syn. Enteromorpha) was investigated. PDMS elastomers of constant thickness (100 mm in the adhesive base of the adherand and deformation of the PDMS film. Keywords: Ulva, spores, green algae

Chaudhury, Manoj K.

187

SPECIES DETERMINATION OF GREEN ALGAE ISOLATED FROM JEPARA COASTAL REGION BASED ON MICROBIOLOGICAL, ECOPHYSIOLOGICAL AND MOLECULAR CHARACTERIZATION FOR IMPROVEMENT OF CAROTENOID PRODUCTION  

Microsoft Academic Search

A local isolate of green algae called C1 from Jepar a waters is usually used as a source for carotenoid supplement for animal fisheries in the l ocal area. This indigenous algae has been successfully purificated. Although the local isola te was known as eucaryotic green algae Dunaliella, our previous molecular study by 18S rDNA analysis t o determine the

Hermin Pancasakti Kusumaningrum; Endang Kusdiyantini; Triwibowo Yuwono

188

Studying photoprotective processes in the green alga Chlorella pyrenoidosa using nonlinear laser fluorimetry.  

PubMed

We use an advanced fluorescence method of Nonlinear Laser Fluorimetry in combination with Fluorescence Induction and Relaxation technique to study the influence of excess-light conditions on the physiological state of the green alga Chlorella pyrenoidosa. We demonstrate that zeaxanthin-dependent non-photochemical quenching leads to a significant increase in the rate constant of singlet-singlet annihilation of chlorophyll a excited state, which suggests profound conformational changes in the light-harvesting complexes of photosystem II. PMID:22308058

Fadeev, Victor V; Gorbunov, Maxim Y; Gostev, Timofey S

2012-07-01

189

Trails of Green Alga Hydrogen Research – from Hans Gaffron to New Frontiers  

Microsoft Academic Search

This paper summarizes aspects of the history of photosynthetic hydrogen research, from the pioneering discovery of Hans Gaffron\\u000a over 60 years ago to the potential exploitation of green algae in commercial H2-production. The trail started as a mere scientific curiosity, but promises to be a most important discovery, one that leads\\u000a photosynthesis research to important commercial applications. Progress achieved in

Anastasios Melis; Thomas Happe

2004-01-01

190

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

191

Molecular Genetics of Lipid Metabolism in the Model Green Alga Chlamydomonas reinhardtii  

Microsoft Academic Search

\\u000a Research focusing on microalgae is currently experiencing a renaissance due to the potential of microalgae for providing biofuels\\u000a without competing with food crops. Despite this potential, our knowledge of neutral and membrane lipid metabolism in microalgae\\u000a is very limited, and opportunities to explore lipid metabolism in microalgae and contrast it to plant lipid metabolism abound.\\u000a The unicellular green alga Chlamydomonas

Eric R. Moellering; Rachel Miller; Christoph Benning

192

Nitrogenase activity in the blue-green alga Plectonema boryanum strain 594  

Microsoft Academic Search

The non-heterocystous filamentous blue-green alga, Plectonema boryanum strain 594 reduces acetylene to ethylene, incorporates 15N2 into cell protoplasm, and grows readily in medium free of combined nitrogen, when incubated in a gas phase without added oxygen. Cells grown in the presence of 50 mg\\/l of ammonium-nitrogen do not reduce acetylene, and a concentration of 0.015 atm. CO in the gas

W. D. P. Stewart; M. Lex

1970-01-01

193

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

194

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

195

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

196

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

197

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

198

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

Microsoft Academic Search

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

M. Annusuyadevi; G. Subbulakshmi; K. Madhairdevi; L. V. Venkalaramein

1981-01-01

199

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

200

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

201

Small G proteins of two green algae are localized to exocytic compartments and to flagella  

Microsoft Academic Search

The Ypt\\/Rab proteins are small GTPases, which belong to the Ras superfamily and have been shown to be involved in endo-and exocytosis in mammalian cells and yeast. Using affinity-purified antibodies specific for four Ypt proteins, namely Ypt1p, Ypt4p, Ypt5p and Ypt6p, of the multicellular green alga Volvox carteri (YptVp) and its close unicellular relative Chlamydomonas reinhardtii (YptCp), we examined the

Hans Huber; Kurt Beyser; Stefan Fabry

1996-01-01

202

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

203

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

204

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

205

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

206

Nostofungicidine, an antifungal lipopeptide from the field-grown terrestrial blue-green alga Nostoc commune  

Microsoft Academic Search

In the course of our screening program for bioactive compounds, a novel lipopeptide, nostofungicidine (1), was isolated from the methanolic extract of a fiel-grown terrestrial blue-green alga, Nostoc commune. The structure of nostofungicidine was elucidated by chemical degradation and extensive NMR measurements including DQF-COSY, HOHAHA, HMBC, and ROESY techniques. Nostofungicidine contains a novel ?-amino acid, 3-amino-6-hydroxy stearic acid (Ahs) in

Shin-ichiro Kajiyama; Hiroshi Kanzaki; Kazuyoshi Kawazu; Akio Kobayashi

1998-01-01

207

Bioaccumulation of metals by the green alga Ulva rigida from Thermaikos Gulf, Greece  

Microsoft Academic Search

Fe, Pb, Cu, Zn and Cd concentrations in the green alga Ulva rigida C. Agardh and in the sediment and seawater were studied at five stations of the Thermaikos Gulf, which is the recipient of domestic and industrial wastes. The relative abundance of metals in U. rigida and seawater (concerning Zn, Pb, Cu, Cd) decreased in the order: Fe>Zn>Pb>Cu>Cd, whereas

S Haritonidis; P Malea

1999-01-01

208

Filtration of green algae and cyanobacteria by Nile tilapia, Oreochromis niloticus, in the Partitioned Aquaculture System  

Microsoft Academic Search

Nile tilapia, Oreochromis niloticus, held in a timed pulse fed Continuous Stirred Tank Reactor (CSTR) were provided Partitioned Aquaculture System (PAS) algal-rich water dominated by green algae (i.e., Scenedesmus and Ankistrodesmus) and cyanobacteria (i.e., Microcystis and Merismopedia) to determine filtration rates (FR). A similar number and size of tilapias were stocked at 1.5 kg\\/tank into each of the six CSTRs

Hakan Turker; Arnold G Eversole; David E Brune

2003-01-01

209

Heterotrimeric G proteins in green algae: an early innovation in the evolution of the plant lineage.  

PubMed

Heterotrimeric G-proteins (G-proteins, hereafter) are important signaling components in all eukaryotes. The absence of these proteins in the sequenced genomes of Chlorophyaceaen green algae has raised questions about their evolutionary origin and prevalence in the plant lineage. The existence of G-proteins has often been correlated with the acquisition of embryophytic life-cycle and/or terrestrial habitats of plants which occurred around 450 million years ago. Our discovery of functional G-proteins in Chara braunii, a representative of the Charophycean green algae, establishes the existence of this conserved signaling pathway in the most basal plants and dates it even further back to 1-1.5 billion years ago. We have now identified the sequence homologs of G-proteins in additional algal families and propose that green algae represent a model system for one of the most basal forms of G-protein signaling known to exist to date. Given the possible differences that exist between plant and metazoan G-protein signaling mechanisms, such basal organisms will serve as important resources to trace the evolutionary origin of proposed mechanistic differences between the systems as well as their plant-specific functions. PMID:24614119

Hackenberg, Dieter; Pandey, Sona

2014-01-01

210

Cryptic sex in the smallest eukaryotic marine green alga.  

PubMed

Ostreococcus spp. are common worldwide oceanic picoeukaryotic pelagic algae. The complete genomes of three strains from different ecological niches revealed them to represent biologically distinct species despite their identical cellular morphologies (cryptic species). Their tiny genomes (13 Mb), with approximately 20 chromosomes, are colinear and densely packed with coding sequences, but no sexual life cycle has been described. Seventeen new strains of one of these species, Ostreococcus tauri, were isolated from 98 seawater samplings from the NW Mediterranean by filtering, culturing, cloning, and plating for single colonies and identification by sequencing their ribosomal 18S gene. In order to find the genetic markers for detection of polymorphisms and sexual recombination, we used an in silico approach to screen available genomic data. Intergenic regions of DNA likely to evolve neutrally were analyzed following polymerase chain reaction amplification of sequences using flanking primers from adjacent conserved coding sequences that were present as syntenic pairs in two different species of Ostreococcus. Analyses of such DNA regions from eight marker loci on two chromosomes from each strain revealed that the isolated O. tauri clones were haploid and that the overall level of polymorphism was approximately 0.01. Four different genetic tests for recombination showed that sexual exchanges must be inferred to account for the between-locus and between-chromosome marker combinations observed. However, our data suggest that sexual encounters are infrequent because we estimate the frequency of meioses/mitoses among the sampled strains to be 10(-6). Ostreococcus tauri and related species encode and express core genes for mitosis and meiosis, but their mechanisms of cell division and recombination, nevertheless, remain enigmatic because a classical eukaryotic spindle with 40 canonical microtubules would be much too large for the available approximately 0.9-microm(3) cellular volume. PMID:19734297

Grimsley, Nigel; Péquin, Bérangčre; Bachy, Charles; Moreau, Hervé; Piganeau, Gwenaël

2010-01-01

211

BROWN ALGAE Colpomenia sinuosa  

E-print Network

BROWN ALGAE Colpomenia sinuosa GREEN ALGAE Dictyosphaeria cavernosa Amphiroa fragilissima Gelidiopsis intricata Botryocladia pyriformis RED ALGAE CYANOBACTERIA Oscillitoria acuminata Schizothrix sp. "ALGAE"­ A DIVERSE ASSORTMENT OF LIFE FORMS Photosynthesis is performed by a taxonomically diverse

Sullivan, Matthew B.

212

Development of a UV laser-induced fluorescence lidar for monitoring blue-green algae in Lake Suwa.  

PubMed

We developed a UV (355 nm) laser-induced fluorescence (LIF) lidar for monitoring the real-time status of blue-green algae. Since the fluorescence spectrum of blue-green algae excited by 355 nm showed the specific fluorescence at 650 nm, the lidar was designed to be able to detect the 650 nm fluorescence as a surveillance method for the algae. The usefulness was confirmed by observation at Lake Suwa over four years (2005-2008). The detection limit of the LIF lidar was 16.65 mg/L for the blue-green algae, which is the range of concentrations in the safe level set by the World Health Organization. PMID:25402791

Saito, Yasunori; Takano, Kengo; Kobayashi, Fumitoshi; Kobayashi, Kazuki; Park, Ho-Dong

2014-10-20

213

Impact of green algae on the measurement of Microcystis aeruginosa populations in lagoon-treated wastewater with an algae online analyser.  

PubMed

Tests on the algae online analyser (AOA) showed that there was a strong direct linear correlation between cell density and in vivo Chl-a concentration for M. aeruginosa over the range of interest for a biologically treated effluent at a wastewater treatment plant (25,000-65,000?cells?mL(-1), equivalent to a biovolume of 2-6?mm(3?)L(-1)). However, the AOA can provide an overestimate or underestimate of M. aeruginosa populations when green algae are present in the effluent, depending on their species and relative numbers. The results from this study demonstrated that the green algae (e.g., Euglena gracilis, Chlorella sp.) in the field phytoplankton population should be considered during calibration. In summary, the AOA has potential for use as an alert system for the presence of M. aeruginosa, and thus potentially of cyanobacterial blooms, in wastewater stabilization ponds. PMID:25204421

Nguyen, Thang; Roddick, Felicity A; Fan, Linhua

2015-03-01

214

Acute toxicity of live and decomposing green alga Ulva ( Enteromorpha) prolifera to abalone Haliotis discus hannai  

NASA Astrophysics Data System (ADS)

From 2007 to 2009, large-scale blooms of green algae (the so-called "green tides") occurred every summer in the Yellow Sea, China. In June 2008, huge amounts of floating green algae accumulated along the coast of Qingdao and led to mass mortality of cultured abalone and sea cucumber. However, the mechanism for the mass mortality of cultured animals remains undetermined. This study examined the toxic effects of Ulva ( Enteromorpha) prolifera, the causative species of green tides in the Yellow Sea during the last three years. The acute toxicity of fresh culture medium and decomposing algal effluent of U. prolifera to the cultured abalone Haliotis discus hannai were tested. It was found that both fresh culture medium and decomposing algal effluent had toxic effects to abalone, and decomposing algal effluent was more toxic than fresh culture medium. The acute toxicity of decomposing algal effluent could be attributed to the ammonia and sulfide presented in the effluent, as well as the hypoxia caused by the decomposition process.

Wang, Chao; Yu, Rencheng; Zhou, Mingjiang

2011-05-01

215

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

216

Genomic analysis of organismal complexity in the multicellular green alga Volvox carteri  

SciTech Connect

Analysis of the Volvox carteri genome reveals that this green alga's increased organismal complexity and multicellularity are associated with modifications in protein families shared with its unicellular ancestor, and not with large-scale innovations in protein coding capacity. The multicellular green alga Volvox carteri and its morphologically diverse close relatives (the volvocine algae) are uniquely suited for investigating the evolution of multicellularity and development. We sequenced the 138 Mb genome of V. carteri and compared its {approx}14,500 predicted proteins to those of its unicellular relative, Chlamydomonas reinhardtii. Despite fundamental differences in organismal complexity and life history, the two species have similar protein-coding potentials, and few species-specific protein-coding gene predictions. Interestingly, volvocine algal-specific proteins are enriched in Volvox, including those associated with an expanded and highly compartmentalized extracellular matrix. Our analysis shows that increases in organismal complexity can be associated with modifications of lineage-specific proteins rather than large-scale invention of protein-coding capacity.

Prochnik, Simon E.; Umen, James; Nedelcu, Aurora; Hallmann, Armin; Miller, Stephen M.; Nishii, Ichiro; Ferris, Patrick; Kuo, Alan; Mitros, Therese; Fritz-Laylin, Lillian K.; Hellsten, Uffe; Chapman, Jarrod; Simakov, Oleg; Rensing, Stefan A.; Terry, Astrid; Pangilinan, Jasmyn; Kapitonov, Vladimir; Jurka, Jerzy; Salamov, Asaf; Shapiro, Harris; Schmutz, Jeremy; Grimwood, Jane; Lindquist, Erika; Lucas, Susan; Grigoriev, Igor V.; Schmitt, Rudiger; Kirk, David; Rokhsar, Daniel S.

2010-07-01

217

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. PMID:23569879

Bhagavathy, S; Sumathi, P

2012-01-01

218

Anaerobic Metabolism in the N-Limited Green Alga Selenastrum minutum1  

PubMed Central

The onset of anaerobiosis in darkened, N-limited cells of the green alga Selenastrum minutum (Naeg.) Collins elicited the following metabolic responses. There was a rapid decrease in energy charge from 0.85 to a stable lower value of 0.6 accompanied by rapid increases in pyruvate/phosphoenolpyruvate and fructose-1,6-bisphosphate/fructose-6-phosphate ratios indicating activation of pyruvate kinase and 6-phosphofructokinase, respectively. There was also a large increase in fructose-2,6-bisphosphate, which, since this alga lacks pyrophosphate dependent 6-phosphofructokinase, can be inferred to inhibit gluconeogenic fructose-1,6-bisphosphatase activity. These changes resulted in an approximately twofold increase in the rate of starch breakdown indicating a Pasteur effect. The Pasteur effect was accompanied by accumulation of d-lactate, ethanol and succinate as fermentation end-products, but not malate. Accumulation of succinate was facilitated by reductive carbon metabolism by a partial TCA cycle (GC Vanlerberghe, AK Horsey, HG Weger, DH Turpin [1989] Plant Physiol 91: 1551-1557). An initial stoichiometric decline in aspartate and increases in succinate and alanine suggests that aspartate catabolism provides an initial source of carbon for reduction to succinate under anoxic conditions. These observations allow us to develop a model for the regulation of anaerobic carbon metabolism and a model for short-term and long-term strategies for succinate accumulation in a green alga. PMID:16667805

Vanlerberghe, Greg C.; Feil, Regina; Turpin, David H.

1990-01-01

219

Experimental Studies on Sexual Reproduction in Diatoms  

Microsoft Academic Search

The diatoms are the most speciose group of algae, having global ecological significance in the carbon and silicon cycles. They are almost unique among algae in being diplontic, and sexual reproduction is an obligate stage in the life cycle of most diatom species. It is unclear which are the principal factors that have fostered the evolutionary success of diatoms, but

Victor A. Chepurnov; David G. Mann; Koen Sabbe; Wim Vyverman

2004-01-01

220

Divergence of the mitochondrial electron transport chains from the green alga Chlamydomonas reinhardtii and its colorless close relative Polytomella sp  

Microsoft Academic Search

Compelling evidence exists that the colorless algae of the genus Polytomella arose from a green Chlamydomonas-like ancestor by losing its functional photosynthetic apparatus. Due to the close relationship between the colorless and the green chlorophyte, Polytomella sp. appeared as a useful indicative framework for structural studies of Chlamydomonas reinhardtii mitochondria. However, comparative studies reported here unexpectedly revealed significant differences between

Robert van Lis; Diego González-Halphen; Ariane Atteia

2005-01-01

221

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

222

Genomic analysis of organismal complexity in the multicellular green alga Volvox carteri.  

PubMed

The multicellular green alga Volvox carteri and its morphologically diverse close relatives (the volvocine algae) are well suited for the investigation of the evolution of multicellularity and development. We sequenced the 138-mega-base pair genome of V. carteri and compared its approximately 14,500 predicted proteins to those of its unicellular relative Chlamydomonas reinhardtii. Despite fundamental differences in organismal complexity and life history, the two species have similar protein-coding potentials and few species-specific protein-coding gene predictions. Volvox is enriched in volvocine-algal-specific proteins, including those associated with an expanded and highly compartmentalized extracellular matrix. Our analysis shows that increases in organismal complexity can be associated with modifications of lineage-specific proteins rather than large-scale invention of protein-coding capacity. PMID:20616280

Prochnik, Simon E; Umen, James; Nedelcu, Aurora M; Hallmann, Armin; Miller, Stephen M; Nishii, Ichiro; Ferris, Patrick; Kuo, Alan; Mitros, Therese; Fritz-Laylin, Lillian K; Hellsten, Uffe; Chapman, Jarrod; Simakov, Oleg; Rensing, Stefan A; Terry, Astrid; Pangilinan, Jasmyn; Kapitonov, Vladimir; Jurka, Jerzy; Salamov, Asaf; Shapiro, Harris; Schmutz, Jeremy; Grimwood, Jane; Lindquist, Erika; Lucas, Susan; Grigoriev, Igor V; Schmitt, Rüdiger; Kirk, David; Rokhsar, Daniel S

2010-07-01

223

DNA barcoding of a new record of epi-endophytic green algae Ulvella leptochaete (Ulvellaceae, Chlorophyta) in India.  

PubMed

Epi-endophytic green algae comprise one of the most diverse and phylogenetically primitive groups of green algae and are considered to be ubiquitous in the world's oceans; however, no reports of these algae exist from India. Here we report the serendipitous discovery of Ulvella growing on intertidal green algae Cladophora glomerata and benthic red algae Laurencia obtusa collected from India. DNA barcodes at nuclear ribosomal DNA Internal Transcriber Spacer (nrDNA ITS) 1 and 2 regions for Indian isolates from the west and east coasts have been generated for the first time. Based on morphology and DNA barcoding, isolates were identified as Ulvella leptochaete. Phylogenetic reconstruction of concatenated dataset using Maximum Likelihood method differentiated Indian isolates from other accessions of this alga available in Genbank, albeit with low bootstrap support. Monophyly of Ulvella leptochaete was obvious in both of our phylogenetic analyses. With this first report of epi-endophytic algae from Indian territorial waters, the dire need to catalogue its cryptic diversity is highlighted and avenues of future research are discussed. PMID:25116625

Bast, Felix; Bhushan, Satej; John, Aijaz Ahmad

2014-09-01

224

Toxicity of hexazinone and diquat to green algae, diatoms, cyanobacteria and duckweed  

Microsoft Academic Search

Hexazinone and diquat are two broad-spectrum contact herbicides used in a variety of crop and non-crop applications. Both pesticides are highly water soluble and persistent in the aquatic system. Hexazinone is mobile in soil and, thus, the potential for leaching into ground water and for overland runoff into surface water is high; diquat, however, is rapidly bound by soil and

Hans G. Peterson; Céline Boutin; Kathryn E. Freemark; Pamela A. Martin

1997-01-01

225

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. PMID:24809511

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

2014-01-01

226

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

227

The identification of putative RNA polymerase II C-terminal domain associated proteins in red and green algae.  

PubMed

A tandemly repeated C-terminal domain (CTD) of the largest subunit of RNA polymerase II is functionally essential and strongly conserved in many organisms, including animal, yeast and plant models. Although present in simple, ancestral red algae, CTD tandem repeats have undergone extensive modifications and degeneration during the evolutionary transition to developmentally complex rhodophytes. In contrast, CTD repeats are conserved in both green algae and their more complex land plant relatives. Understanding the mechanistic differences that underlie these variant patterns of CTD evolution requires knowledge of CTD-associated proteins in these 2 lineages. To provide an initial baseline comparison, we bound potential phospho-CTD associated proteins (PCAPs) to artificially synthesized and phosphorylated CTD repeats from the unicellular red alga Cyanidioschyzon merolae and green alga Chlamydomonas reinhardtii. Our results indicate that red and green algae share a number of PCAPs, including kinases and proteins involved in mRNA export. There also are important taxon-specific differences, including mRNA splicing-related PCAPs recovered from Chlamydomonas but not Cyanidioschyzon, consistent with the relative intron densities in green and red algae. Our results also offer the first experimental indication that different proteins bind 2 distinct types of repeats in Cyanidioschyzon, suggesting a division of function between the proximal and distal CTD, similar to patterns identified in more developmentally complex model organisms. PMID:25483605

Yang, Chunlin; Hager, Paul W; Stiller, John W

2014-10-20

228

A new model for the calcification of the green macro-alga Halimeda opuntia (Lamouroux)  

NASA Astrophysics Data System (ADS)

Halimeda opuntia is a cosmopolitan marine calcifying green alga in shallow tropical marine environments. Besides Halimeda's contribution to a diverse habitat, the alga is an important sediment producer. Fallen calcareous segments of Halimeda spp. are a major component of carbonate sediments in many tropical settings and play an important role in reef framework development and carbonate platform buildup. Consequently the calcification of H. opuntia accounts for large portions of the carbonate budget in tropical shallow marine ecosystems. Earlier studies investigating the calcification processes of Halimeda spp. have tended to focus on the microstructure or the physiology of the alga, thus overlooking the interaction of physiological and abiotic processes behind the formation of the skeleton. By analyzing microstructural skeletal features of Halimeda segments with the aid of scanning electron microscopy and relating their occurrence to known physiological processes, we have been able to identify the initiation of calcification within an organic matrix and demonstrate that biologically induced cementation is an important process in calcification. For the first time, we propose a model for the calcification of Halimeda spp. that considers both the alga's physiology and the carbon chemistry of the seawater with respect to the development of different skeletal features. The presence of an organic matrix and earlier detected external carbonic anhydrase activity suggest that Halimeda spp. exhibit biotic precipitation of calcium carbonate, as many other species of marine organisms do. On the other hand, it is the formation of micro-anhedral carbonate through the alga's metabolism that leads to a cementation of living segments. Precisely, this process allows H. opuntia to contribute substantial amounts of carbonate sediments to tropical shallow seas.

Wizemann, André; Meyer, Friedrich W.; Westphal, Hildegard

2014-12-01

229

Reproduction-related effects of green alga Coccomyxa sp. infestation in the horse mussel Modiolus modiolus.  

PubMed

The effects of Coccomyxa sp. infestation on the reproductive characteristics of the horse mussel Modiolus modiolus from the north-western Pacific (Peter the Great Bay, Sea of Japan) are demonstrated in this study. The mussels were collected monthly from May to September of 2009, and the prevalence of females and males with green tissues was 39% and 47%, respectively. Overall, the green alga infection caused a mild effect on gametogenesis in the horse mussel. The dynamics of gonad development in the healthy and infected mussels during the study period was generally similar, with the spawning being partial and occurring from the beginning of June to the first half of September; total spawning was recorded at the end of this period. However, several negative reproduction-related effects of the green alga infestation were observed, i.e., general gonadal underdevelopment, which was apparent from significant decrease in the acinus areas of the ovaries and testes and an increase in the connective tissue layer between the acini, a delay in some stages of the reproductive cycle and production of decreased number of spermatozoa and large vitellogenic oocytes, especially in the early spawning period (June). All of these results suggest a reduced reproductive output for the infected mussels. PMID:23439265

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

2013-05-01

230

Photosynthetic biomanufacturing in green algae; production of recombinant proteins for industrial, nutritional, and medical uses.  

PubMed

Recombinant proteins are widely used for industrial, nutritional, and medical applications. Green microalgae have attracted considerable attention recently as a biomanufacturing platform for the production of recombinant proteins for a number of reasons. These photosynthetic eukaryotic microorganisms are safe, scalable, easy to genetically modify through transformation, mutagenesis, or breeding, and inexpensive to grow. Many microalgae species are genetically transformable, but the green alga Chlamydomonas reinhardtii is the most widely used host for recombinant protein expression. An extensive suite of molecular genetic tools has been developed for C. reinhardtii over the last 25 years, including a fully sequenced genome, well-established methods for transformation, mutagenesis and breeding, and transformation vectors for high levels of recombinant protein accumulation and secretion. Here, we review recent successes in the development of C. reinhardtii as a biomanufacturing host for recombinant proteins, including antibodies and immunotoxins, hormones, industrial enzymes, an orally-active colostral protein for gastrointestinal health, and subunit vaccines. In addition, we review the biomanufacturing potential of other green algae from the genera Dunaliella and Chlorella. PMID:24659086

Rasala, Beth A; Mayfield, Stephen P

2015-03-01

231

Removal of toxic chromium from wastewater using green alga Ulva lactuca and its activated carbon.  

PubMed

Biosorption of heavy metals can be an effective process for the removal of toxic chromium ions from wastewater. In this study, the batch removal of toxic hexavalent chromium ions from aqueous solution, saline water and wastewater using marine dried green alga Ulva lactuca was investigated. Activated carbon prepared from U. lactuca by acid decomposition was also used for the removal of chromium from aqueous solution, saline water and wastewater. The chromium uptake was dependent on the initial pH and the initial chromium concentration, with pH approximately 1.0, being the optimum pH value. Langmuir, Freundlich, Redlich-Peterson and Koble-Corrigan isotherm models were fitted well the equilibrium data for both sorbents. The maximum efficiencies of chromium removal were 92 and 98% for U. lactuca and its activated carbon, respectively. The maximum adsorption capacity was found to be 10.61 and 112.36 mg g(-1) for dried green alga and activated carbon developed from it, respectively. The adsorption capacities of U. lactuca and its activated carbon were independent on the type of solution containing toxic chromium and the efficiency of removal was not affected by the replacing of aqueous solution by saline water or wastewater containing the same chromium concentration. Two hours were necessary to reach the sorption equilibrium. The chromium uptake by U. lactuca and its activated carbon form were best described by pseudo second-order rate model. This study verifies the possibility of using inactivated marine green alga U. lactuca and its activated carbon as valuable material for the removal of chromium from aqueous solutions, saline water or wastewater. PMID:17360109

El-Sikaily, Amany; El Nemr, Ahmed; Khaled, Azza; Abdelwehab, Ola

2007-09-01

232

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

233

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

234

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

235

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

236

Maturation of ribosomal RNA in blue-green algae in light and darkness  

Microsoft Academic Search

The blue-green algaPlectonema boryanum was chosen for a study of the properties of rRNA of procaryotic organisms. The process of rRNA species maturation was studied\\u000a by labelling RNA with the isotope 32P.23 S and 16 S rRNA molecules each have their own precursors. Molecules with molecular weights of 1.65 X 106 and 1.24xlO6 were identified as precursors of23 S rRNA,

Danuše Sofrová; J. Hladík; J. Ullmann; Sylva Leblová

1978-01-01

237

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

238

Detecting massive green algae ( Ulva prolifera) blooms in the Yellow Sea and East China Sea using Geostationary Ocean Color Imager (GOCI) data  

NASA Astrophysics Data System (ADS)

The historically massive bloom of the green macroalgae Ulva prolifera reported in June-August 2008 around the Qingdao, Yellow Sea, East China Sea and Japan coasts has recurred in a similar season and region. On June 13, 2011, around Qingdao, China, the world's first Geostationary Ocean Color Imager (GOCI) detected an enormous bloom of floating green algae, which originated from the nearshore Subei Bank, China. The large floating green algae patches were observed along and across the Yellow Sea and in the East China Sea during 2011 summer by various oceanic cruises. To detect the massive macroalgae blooms from space, we analyzed their spectral characteristics from in situ optical measurements and satellite-derived green algae spectra. An "Index of floating Green Algae for GOCI" (IGAG) was developed from the multiple spectral band ratios using three wavelengths (555, 660, 745 nm), which the spectral response of green algae reflected at 555, 745, and 865 nm and absorbed at 660 and 680 nm. The results were compared with those obtained by the normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), and Korea Ocean Satellite Center (KOSC) approaches. An advantage of the IGAG method was that muted or subtle signals of floating green algae were enhanced and separated from surrounding complex water signals. Although maps of floating green algae derived by the other approaches delineated dense green algae, they were less sensitive to subtle (less dense) features and in cases of nearby cloudy or complex water conditions. The floating green algae maps from IGAG provided a more robust estimate of wide floating green algae blooms than those derived using NDVI, EVI, or KOSC approaches. The IGAG approach should be useful for tracing and monitoring changes in green algae blooms on regional and global scales.

Son, Young Baek; Min, Jee-Eun; Ryu, Joo-Hyung

2012-09-01

239

Biotransformation of sinapic acid by the green algae Stichococcus bacillaris 155LTAP and Ankistrodesmus braunii C202.7a  

Microsoft Academic Search

Sinapic acid was bioconverted by the green alga Stichococcus bacillaris into 4-hydroxy-3,5-dimethoxybenzoic acid, 4-hydroxy-3,5-dimethoxybenzaldehyde and 4-hydroxy-3,5-dimethoxybenzylic alcohol. Incubation of sinapic acid in a culture of the alga Ankistrodesmus braunii gave 3,6-dihydroxy-2,4-dimethoxy-7H-benzocyclohepten-7-one, a new compound formed by bioconversion of thomasidioic acid, the primary oxidative product of sinapic acid.

Marina DellaGreca; Gabriele Pinto; Antonino Pollio; Lucio Previtera; Fabio Temussi

2003-01-01

240

The influence of daylength, light intensity and temperature on the growth rates of planktonic blue-green algae  

Microsoft Academic Search

The in vitro growth rates under continuous light of the four dominant blue-green algae in Lough Neagh, Anabaena flos-aquae Bréb., Aphanizomenon flos-aquae Ralfs fa. gracile Lemm., Oscillatoria agardhii Gom. and Oscillatoria redekei van Goor were slower than in situ rates from Lough Neagh that had been corrected for hours of light received by the algae. However, by culturing on a

R. H. Foy; C. E. Gibson; R. V. Smith

1976-01-01

241

The Cell Wall as a Barrier to Uptake of Metal Ions in the Unicellular Green Alga Chlamydomonas reinhardtii (Chlorophyceae)  

Microsoft Academic Search

The cell walls of plants, including those of algae, have the capacity to bind metal ions in negatively charged sites. The\\u000a authors had already shown that the wild type (walled) strain of the unicellular green alga Chlamydomonas reinhardtii Dangeard was more tolerant to Cd, Co, Cu, and Ni than a wall-less mutant of the same species. The objective of the

S. M. Macfie; P. M. Welbourn

2000-01-01

242

Diatom genomics: genetic acquisitions and mergers.  

PubMed

Diatom algae arose by two-step endosymbiosis. The complete genome of the diatom Thalassiosira pseudonana has now been sequenced, allowing us to reconstruct the remarkable intracellular gene transfers that occurred during this convoluted cellular evolution. PMID:15620637

Nisbet, R Ellen R; Kilian, Oliver; McFadden, Geoffrey I

2004-12-29

243

Size-dependent ecotoxicity of barium titanate particles: the case of Chlorella vulgaris green algae.  

PubMed

Studies have been demonstrating that smaller particles can lead to unexpected and diverse ecotoxicological effects when compared to those caused by the bulk material. In this study, the chemical composition, size and shape, state of dispersion, and surface's charge, area and physicochemistry of micro (BT MP) and nano barium titanate (BT NP) were determined. Green algae Chlorella vulgaris grown in Bold's Basal (BB) medium or Seine River water (SRW) was used as biological indicator to assess their aquatic toxicology. Responses such as growth inhibition, cell viability, superoxide dismutase (SOD) activity, adenosine-5-triphosphate (ATP) content and photosynthetic activity were evaluated. Tetragonal BT (~170 nm, 3.24 m(2) g(-1) surface area) and cubic BT (~60 nm, 16.60 m(2) g(-1)) particles were negative, poorly dispersed, and readily aggregated. BT has a statistically significant effect on C. vulgaris growth since the lower concentration tested (1 ppm), what seems to be mediated by induced oxidative stress caused by the particles (increased SOD activity and decreased photosynthetic efficiency and intracellular ATP content). The toxic effects were more pronounced when the algae was grown in SRW. Size does not seem to be an issue influencing the toxicity in BT particles toxicity since micro- and nano-particles produced significant effects on algae growth. PMID:25763523

Polonini, Hudson C; Brandăo, Humberto M; Raposo, Nádia R B; Brandăo, Marcos Antônio F; Mouton, Ludovic; Couté, Alain; Yéprémian, Claude; Sivry, Yann; Brayner, Roberta

2015-05-01

244

In Vivo Characterization of the Electrochemical Proton Gradient Generated in Darkness in Green Algae and Its Kinetic Effects on Cytochrome b6f Turnover  

E-print Network

Algae and Its Kinetic Effects on Cytochrome b6f Turnover Giovanni Finazzi*, and Fabrice Rappaport CNRSV) fits well with estimations based on the ATP/ADP ratio measured in green algae under the same conditions dark incubation of algae, the electrochemical transmembrane potential is determined only

245

Molecular identification of green algae from the rafts based infrastructure of Porphyra yezoensis.  

PubMed

To provide more information on the origin of the Ulva prolifera bloom in Qingdao sea area in China from 2007 to 2011, the diversity of green algae growing on the rafts of Porphyra yezoensis on the coast in Jiangsu Province was investigated based on ITS, rbcL and 5S sequences. Eighty-four of green algal samples from various sites and cruises in 2010 and 2011 were collected. According to ITS and rbcL sequences, samples from the rafts of P. yezoensis fell into four clades: Ulva linza-procera-prolifera (LPP) complex, Ulva flexuosa, Blidingia sp. and Urospora spp. However, based on the 5S rDNA, a more resolved DNA marker, only one of the 84 samples belonged to U. prolifera. Combined with the previous reports, it is likely that U. prolifera bloom in Qingdao sea area might consist of more than one origin, and Porphyra cultivation rafts might be one of the causes. PMID:22858010

Shen, Qi; Li, Hongye; Li, Yan; Wang, Zongling; Liu, Jiesheng; Yang, Weidong

2012-10-01

246

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. PMID:24592162

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

2014-01-01

247

Larvicidal algae.  

PubMed

Although most algae are nutritious food for mosquito larvae, some species kill the larvae when ingested in large quantities. Cyanobacteria (blue-green algae) that kill larvae do so by virtue of toxicity. While blue-green algae toxins may offer possibilities for delivery as larvicides, the toxicity of live blue-green algae does not seem consistent enough for live algae to be useful for mosquito control. Certain species of green algae in the order Chlorococcales kill larvae primarily because they are indigestible. Where these algae are abundant in nature, larvae consume them to the exclusion of other food and then starve. Under the right circumstances, it is possible to introduce indigestible algae into a breeding habitat so they become abundant enough to render it unsuitable for mosquito production. The algae can persist for years, even if the habitat dries periodically. The main limitation of indigestible algae lies in the fact that, under certain conditions, they may not replace all the nutritious algae in the habitat. More research on techniques to ensure complete replacement will be necessary before indigestible algae can go into operational use for mosquito control. PMID:17855939

Marten, Gerald G

2007-01-01

248

In vitro cytotoxicity assessment of ulvan, a polysaccharide extracted from green algae.  

PubMed

Sustainable exploitation and valorization of natural marine resources represents a highly interesting platform for the development of novel biomaterials, with both economic and environmental benefits. In this context, toxicity data is regarded as a crucial and fundamental knowledge prior to any advances in the application development of natural derived polymers. In the present work, cytotoxicity of ulvan extracted from green algae Ulva lactuca was assessed by means of standard in vitro cytotoxicity assays. Fibroblast-like cells were incubated in the presence of this green algae's polysaccharide, and cell viability was assayed through 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium test. In addition, double stranded DNA and total protein were quantified in order to assess cell number. In order to establish ulvan's non-cytotoxic behaviour, the effect of this polysaccharide on cellular metabolic activity and cell number was directly compared to hyaluronic acid (HA), used as a non-cytotoxic control material. In this study, ulvan demonstrated promising results in terms of cytotoxicity, comparable to the currently used HA, which suggests that ulvan can be considered as non-toxic in the range of concentrations studied. PMID:22972627

Alves, Anabela; Sousa, Rui A; Reis, Rui L

2013-08-01

249

Phagotrophy by the picoeukaryotic green alga Micromonas: implications for Arctic Oceans.  

PubMed

Photosynthetic picoeukaryotes (PPE) are recognized as major primary producers and contributors to phytoplankton biomass in oceanic and coastal environments. Molecular surveys indicate a large phylogenetic diversity in the picoeukaryotes, with members of the Prymnesiophyceae and Chrysophyseae tending to be more common in open ocean waters and Prasinophyceae dominating coastal and Arctic waters. In addition to their role as primary producers, PPE have been identified in several studies as mixotrophic and major predators of prokaryotes. Mixotrophy, the combination of photosynthesis and phagotrophy in a single organism, is well established for most photosynthetic lineages. However, green algae, including prasinophytes, were widely considered as a purely photosynthetic group. The prasinophyte Micromonas is perhaps the most common picoeukaryote in coastal and Arctic waters and is one of the relatively few cultured representatives of the picoeukaryotes available for physiological investigations. In this study, we demonstrate phagotrophy by a strain of Micromonas (CCMP2099) isolated from Arctic waters and show that environmental factors (light and nutrient concentration) affect ingestion rates in this mixotroph. In addition, we show size-selective feeding with a preference for smaller particles, and determine P vs I (photosynthesis vs irradiance) responses in different nutrient conditions. If other strains have mixotrophic abilities similar to Micromonas CCMP2099, the widespread distribution and frequently high abundances of Micromonas suggest that these green algae may have significant impact on prokaryote populations in several oceanic regimes. PMID:24553471

McKie-Krisberg, Zaid M; Sanders, Robert W

2014-10-01

250

Precambrian palaeontology in the light of molecular phylogeny - an example: the radiation of the green algae  

NASA Astrophysics Data System (ADS)

The problem of the antiquity of the radiation of the green algae (phylum Viridiplantae) has been hotly debated and is still controversial today. A method combining Precambrian paleontology and molecular phylogeny is applied to shed light on this topic. As a critical method, molecular phylogeny is essential for avoiding taxonomic mistakes. As a heuristic method, it helps us to discern to what extent the presence of such and such clade is likely at such and such time, and it may even suggest the attribution of some fossil to a clade whose taxonomic position will be distinctly defined even though it has no previously known representative. Some well characterized Precambrian fossils of green algae are Palaeastrum and Proterocladus at Svanbergfjellet (ca. 750 Ma), Tasmanites and Pterospermella at Thule (ca. 1200 Ma), Spiromorpha at Ruyang (ca. 1200 Ma) and Leiosphaeridia crassa at Roper (ca. 1450 Ma). The position of these fossils in the taxonomy and the phylogeny of the Viriplantae is discussed. The conclusions are that the Chlorophyceae and the Ulvophyceae were separated long before 750 Ma, that the Chlorophyta and the Streptophyta were separated long before 1200 Ma and that the last common ancestor of the Viridiplantae and the Rhodophyta was possibly two billion years old.

Teyssčdre, B.

2007-09-01

251

A novel ether-linked phytol-containing digalactosylglycerolipid in the marine green alga, Ulva pertusa.  

PubMed

Galactosylglycerolipids (GGLs) and chlorophyll are characteristic components of chloroplast in photosynthetic organisms. Although chlorophyll is anchored to the thylakoid membrane by phytol (tetramethylhexadecenol), this isoprenoid alcohol has never been found as a constituent of GGLs. We here described a novel GGL, in which phytol was linked to the glycerol backbone via an ether linkage. This unique GGL was identified as an Alkaline-resistant and Endogalactosylceramidase (EGALC)-sensitive GlycoLipid (AEGL) in the marine green alga, Ulva pertusa. EGALC is an enzyme that is specific to the R-Gal?/?1-6Gal?1-structure of galactolipids. The structure of U. pertusa AEGL was determined following its purification to 1-O-phytyl-3-O-Gal?1-6Gal?1-sn-glycerol by mass spectrometric and nuclear magnetic resonance analyses. AEGLs were ubiquitously distributed in not only green, but also red and brown marine algae; however, they were rarely detected in terrestrial plants, eukaryotic phytoplankton, or cyanobacteria. PMID:25157808

Ishibashi, Yohei; Nagamatsu, Yusuke; Miyamoto, Tomofumi; Matsunaga, Naoyuki; Okino, Nozomu; Yamaguchi, Kuniko; Ito, Makoto

2014-10-01

252

The charophycean green algae provide insights into the early origins of plant cell walls.  

PubMed

Numerous evolutionary innovations were required to enable freshwater green algae to colonize terrestrial habitats and thereby initiate the evolution of land plants (embryophytes). These adaptations probably included changes in cell-wall composition and architecture that were to become essential for embryophyte development and radiation. However, it is not known to what extent the polymers that are characteristic of embryophyte cell walls, including pectins, hemicelluloses, glycoproteins and lignin, evolved in response to the demands of the terrestrial environment or whether they pre-existed in their algal ancestors. Here we show that members of the advanced charophycean green algae (CGA), including the Charales, Coleochaetales and Zygnematales, but not basal CGA (Klebsormidiales and Chlorokybales), have cell walls that are comparable in several respects to the primary walls of embryophytes. Moreover, we provide both chemical and immunocytochemical evidence that selected Coleochaete species have cell walls that contain small amounts of lignin or lignin-like polymers derived from radical coupling of hydroxycinnamyl alcohols. Thus, the ability to synthesize many of the components that characterize extant embryophyte walls evolved during divergence within CGA. Our study provides new insight into the evolutionary window during which the structurally complex walls of embryophytes originated, and the significance of the advanced CGA during these events. PMID:21707800

Sřrensen, Iben; Pettolino, Filomena A; Bacic, Antony; Ralph, John; Lu, Fachuang; O'Neill, Malcolm A; Fei, Zhangzhun; Rose, Jocelyn K C; Domozych, David S; Willats, William G T

2011-10-01

253

Structural characterization and anticoagulant activity of a sulfated polysaccharide from the green alga Codium divaricatum.  

PubMed

A sulfated polysaccharide, designated CP2-1, was isolated from the green alga Codium divaricatum by water extraction and purified by anion-exchange and size-exclusion chromatography. CP2-1 is a galactan which is highly sulfated and substituted with pyruvic acid ketals. On the basis of chemical and spectroscopic analyses, the backbone of CP2-1 was mainly composed of (1?3)-?-d-galactopyranose residues, branched by single (1?)-?-d-galactopyranose units attached to the main chain at C-4 positions. The degree of branching was estimated to be about 12.2%. Sulfate groups were at C-4 of (1?3)-?-d-galactopyranose and C-6 of non-reducing terminal galactose residues. In addition, the ketals of pyruvic acid were found at 3,4- of non-reducing terminal galactose residues forming a five-membered ring. CP2-1 possessed a high anticoagulant activity as assessed by the activated partial thromboplastin time and thrombin time assays. The investigation demonstrated that CP2-1 was an anticoagulant-active sulfated polysaccharide distinguishing from other sulfated polysaccharides from marine green algae. PMID:25659687

Li, Na; Mao, Wenjun; Yan, Mengxia; Liu, Xue; Xia, Zheng; Wang, Shuyao; Xiao, Bo; Chen, Chenglong; Zhang, Lifang; Cao, Sujian

2015-05-01

254

Multiple Metabolic Roles for the Nonphotosynthetic Plastid of the Green Alga Prototheca wickerhamii†  

PubMed Central

The presence of plastids in diverse eukaryotic lineages that have lost the capacity for photosynthesis is well documented. The metabolic functions of such organelles, however, are poorly understood except in the case of the apicoplast in the Apicomplexa, a group of intracellular parasites including Plasmodium falciparum, and the plastid of the green alga Helicosporidium sp., a parasite for which the only host-free stage identified in nature so far is represented by cysts. As a first step in the reconstruction of plastid functions in a nonphotosynthetic, predominantly free-living organism, we searched for expressed sequence tags (ESTs) that correspond to nucleus-encoded plastid-targeted polypeptides in the green alga Prototheca wickerhamii. From 3,856 ESTs, we found that 71 unique sequences (235 ESTs) correspond to different nucleus-encoded putatively plastid-targeted polypeptides. The identified proteins predict that carbohydrate, amino acid, lipid, tetrapyrrole, and isoprenoid metabolism as well as de novo purine biosynthesis and oxidoreductive processes take place in the plastid of P. wickerhamii. Mg-protoporphyrin accumulation and, therefore, plastid-to-nucleus signaling might also occur in this nonphotosynthetic organism, as we identified a transcript which encodes subunit I of Mg-chelatase, the enzyme which catalyzes the first committed step in chlorophyll synthesis. Our data indicate a far more complex metabolism in P. wickerhamii's plastid compared with the metabolic pathways predicted to be located in the apicoplast of P. falciparum and the plastid of Helicosporidium sp. PMID:15701787

Borza, Tudor; Popescu, Cristina E.; Lee, Robert W.

2005-01-01

255

Cell death in the unicellular green alga Micrasterias upon H2O2 induction  

PubMed Central

In the present study we investigate whether the unicellular green alga Micrasterias denticulata is capable of executing programmed cell death (PCD) upon experimental induction and by which morphological, molecular and physiological hallmarks it is characterized. This is particularly interesting as unicellular fresh water green algae growing in shallow bog ponds are exposed to extreme environmental conditions and the capability to perform PCD may provide an important strategy to guarantee survival of the population. The theoretically “immortal” alga Micrasterias is an ideal object for such investigations as it has served as a cell biological model system since many years and details on its growth properties, physiology and ultrastructure throughout the cell cycle are well known. Treatment with low concentrations of H2O2 known to induce PCD in other organisms resulted in severe ultrastructural changes of organelles as observed in TEM. These include deformation and partly disintegration of mitochondria, abnormal dilatation of cisternal rims of dictyosomes, the occurrence of multivesicular bodies, an increase in the number of ER compartments and slight condensation of chromatin. Additionally, a statistically significant increase in caspase-3-like activity could be detected which was abrogated by a caspase-3 inhibitor. Photosynthetic activity measured by fast chlorophyll fluorescence decreased as a consequence of H2O2 exposure whereas pigment composition, except of a reduction in carotenoids, was the same as in untreated controls. TUNEL positive staining and ladder-like degradation of DNA, both frequently regarded as PCD hallmark in higher plants could only be detected in dead Micrasterias cells. PMID:18950431

Darehshouri, Anza; Affenzeller, Matthias; Lütz-Meindl, Ursula

2010-01-01

256

Use of a deviant mitochondrial genetic code in yellow-green algae as a landmark for segregating members within the phylum  

Microsoft Academic Search

Several algae that were previously classified in the phylum Xanthophyta (yellow-green algae) were assigned in 1971 to a new\\u000a phylum, Eustigmatophyta. It was anticipated that the number of algae reclassified to Eustigmatophyta would increase. However,\\u000a due to the fact that the morphological characteristics that segregate eustigmatophytes from other closely related algae can\\u000a be only obtained through laborious electron microscopic techniques,

Megumi Ehara; Yasuko Hayashi-Ishimaru; Yuji Inagaki; Takeshi Ohama

1997-01-01

257

Assessing the ecotoxicity of vinyl chloride using green alga P. subcapitata, nematode C. elegans, and the SOS chromotest in a closed system without headspace  

Microsoft Academic Search

The ecotoxicity of vinyl chloride (VC) was evaluated using green alga, nematode, and the SOS chromotest. The green alga and nematode tested were Pseudokirchneriella subcapitata, and Caenorhabditis elegans, respectively. Because of the tendency of VC to escape from an aqueous exposure medium to the air phase, all tests in the present study were performed in a closed system without headspace

Sun-Hwa Nam; Youn-Joo An

2010-01-01

258

Growth and Metabolism of the Green Alga, Chlorella Pyrenoidosa, in Simulated Microgravity  

NASA Technical Reports Server (NTRS)

The effect of microgravity on living organisms during space flight has been a topic of interest for some time, and a substantial body of knowledge on the subject has accumulated. Despite this, comparatively little information is available regarding the influence of microgravity on algae, even though it has been suggested for long duration flight or occupancy in space that plant growth systems, including both higher plants and algae, are likely to be necessary for bioregenerative life support systems. High-Aspect-Ratio Rotating-Wall Vessel or HARV bioreactors developed at Johnson Space Center provide a laboratory-based approach to investigating the effects of microgravity on cellular reactions. In this study, the HARV bioreactor was used to examine the influence of simulated microgravity on the growth and metabolism of the green alga, Chlorella pyrenoidosa. After the first 2 days of culture, cell numbers increased more slowly in simulated microgravity than in the HARV gravity control; after 7 days, growth in simulated microgravity was just over half (58%) that of the gravity control and at 14 days it was less than half (42%). Chlorophyll and protein were also followed as indices of cell competence and function; as with growth, after 2-3 days, protein and chlorophyll levels were reduced in modeled microgravity compared to gravity controls. Photosynthesis is a sensitive biochemical index of the fitness of photosynthetic organisms; thus, CO2-dependent O2 evolution was tested as a measure of photosynthetic capacity of cells grown in simulated microgravity. When data were expressed with respect to cell number, modeled microgravity appeared to have little effect on CO2 fixation. Thus, even though the overall growth rate was lower for cells cultured in microgravity, the photosynthetic capacity of the cells appears to be unaffected. Cells grown in simulated microgravity formed loose clumps or aggregates within about 2 days of culture, with aggregation increasing over time. Presently, the basis for, or significance of, the cell aggregation is unknown. The results from this study suggest that cell growth and morphological characteristics of green algae may be altered by culture in simulated microgravity. The data obtained to date should provide a solid basis for additional experimentation regarding the influence of modeled microgravity on cell morphology, physiological activity, protein production and possibly gene expression in algal and plant cell systems. The final aim of the study is to provide useful information to elucidate the underlying mechanism for the biological effects of microgravity on cells.

Mills, W. Ronald

2003-01-01

259

Cyanolichens can have both cyanobacteria and green algae in a common layer as major contributors to photosynthesis  

PubMed Central

Background and Aims Cyanolichens are usually stated to be bipartite (mycobiont plus cyanobacterial photobiont). Analyses revealed green algal carbohydrates in supposedly cyanobacterial lichens (in the genera Pseudocyphellaria, Sticta and Peltigera). Investigations were carried out to determine if both cyanobacteria and green algae were present in these lichens and, if so, what were their roles. Methods The types of photobiont present were determined by light and fluorescence microscopy. Small carbohydrates were analysed to detect the presence of green algal metabolites. Thalli were treated with selected strengths of Zn2+ solutions that stop cyanobacterial but not green algal photosynthesis. CO2 exchange was measured before and after treatment to determine the contribution of each photobiont to total thallus photosynthesis. Heterocyst frequencies were determined to clarify whether the cyanobacteria were modified for increased nitrogen fixation (high heterocyst frequencies) or were normal, vegetative cells. Key Results Several cyanobacterial lichens had green algae present in the photosynthetic layer of the thallus. The presence of the green algal transfer carbohydrate (ribitol) and the incomplete inhibition of thallus photosynthesis upon treatment with Zn2+ solutions showed that both photobionts contributed to the photosynthesis of the lichen thallus. Low heterocyst frequencies showed that, despite the presence of adjacent green algae, the cyanobacteria were not altered to increase nitrogen fixation. Conclusions These cyanobacterial lichens are a tripartite lichen symbiont combination in which the mycobiont has two primarily photosynthetic photobionts, ‘co-primary photobionts’, a cyanobacterium (dominant) and a green alga. This demonstrates high flexibility in photobiont choice by the mycobiont in the Peltigerales. Overall thallus appearance does not change whether one or two photobionts are present in the cyanobacterial thallus. This suggests that, if there is a photobiont effect on thallus structure, it is not specific to one or the other photobiont. PMID:22648879

Henskens, Frieda L.; Green, T. G. Allan; Wilkins, Alistair

2012-01-01

260

Increase of nitrogenase activity in the blue-green alga Nostoc muscorum (Cyanobacterium).  

PubMed

Preincubation of the blue-green alga (cyanobacterium) Nostoc muscorum under hydrogen or argon (nongrowing conditions, neither CO(2) nor N(2) or bound nitrogen present) in the light resulted in a two- to fourfold increase of light-induced hydrogen evolution and a 30% increase of acetylene reduction. Preincubation under the same gases in the dark led to a decrease of both activities. Cultivation of algae under a hydrogen-containing atmosphere (N(2), H(2), CO(2)) increased neither hydrogen nor ethylene evolution by the cells. Formation of both ethylene and hydrogen is due to nitrogenase activity, which apparently was induced by the absence of N(2) or bound nitrogen and not by the presence of hydrogen. Inhibitors of protein biosynthesis prevented the increase of nitrogenase activity. Hydrogen uptake by the cells was almost unaffected under all of these conditions. With either ammonia or chloramphenicol present, nitrogenase activity decreased under growing conditions (i.e., an atmosphere of N(2) and CO(2)). The kinetics of decrease were the same with ammonia or chloramphenicol, which was interpreted as being due to rapid protein breakdown with a half-life of approximately 4 h. The decay of nitrogenase activity caused by chloramphenicol could be counteracted by nitrogenase-inducing conditions, i.e., by the absence of N(2) or bound nitrogen. A cell-free system from preconditioned algae with an adenosine 5'-triphosphate-generating system exhibited the same increase or decrease of nitrogenase activity as the intact cell filaments, indicating that this effect resided in the nitrogenase complex only. We tentatively assume that not the whole nitrogenase complex, but merely a subunit or a special protein with regulatory function, is susceptible to fast turnover. PMID:6777364

Scherer, S; Kerfin, W; Böger, P

1980-12-01

261

Anaerobic Metabolism in the N-Limited Green Alga Selenastrum minutum1  

PubMed Central

The green alga Selenastrum minutum (Naeg.) Collins is able to assimilate NH4+ in the dark under anaerobic conditions (GC Vanlerberghe, AK Horsey, HG Weger, DH Turpin [1989] Plant Physiol 91: 1551-1557). In the present study, analysis of metabolites following addition of NH4+ to cells acclimated to anaerobic conditions has shown the following. There was a transient decline in adenylate energy charge from 0.6 to 0.4 followed by a recovery back to ~0.6. This was accompanied by a rapid increase in pyruvate/phosphoenolpyruvate and fructose-1,6-bisphosphate/fructose-6-phosphate ratios indicating activation of pyruvate kinase and 6-phosphofructokinase, respectively. There was also an increase in fructose-2,6-bisphosphate, which, since this alga lacks pyrophosphate dependent 6-phosphofructokinase can be inferred to inhibit gluconeogenic fructose-1,6-bisphosphatase. These changes resulted in an increase in the rate of anaerobic starch breakdown. Anaerobic NH4+ assimilation also resulted in a two-fold increase in the rate of production of the major fermentative end-products in this alga, d-lactate and ethanol. There was no change in the rate of accumulation of the fermentative end product succinate but malate accumulated under anoxia during NH4+ assimilation. A rapid increase in Gln and decline in Glu indicates that primary NH4+ assimilation under anoxia was via glutamine synthetase-glutamate synthase. Almost all N assimilated under these conditions was sequestered in alanine. These results allow us to propose a model for the regulation of carbon metabolism during anaerobic NH4+ assimilation. PMID:16667806

Vanlerberghe, Greg C.; Turpin, David H.

1990-01-01

262

Overview on Biological Activities and Molecular Characteristics of Sulfated Polysaccharides from Marine Green Algae in Recent Years  

PubMed Central

Among the three main divisions of marine macroalgae (Chlorophyta, Phaeophyta and Rhodophyta), marine green algae are valuable sources of structurally diverse bioactive compounds and remain largely unexploited in nutraceutical and pharmaceutical areas. Recently, a great deal of interest has been developed to isolate novel sulfated polysaccharides (SPs) from marine green algae because of their numerous health beneficial effects. Green seaweeds are known to synthesize large quantities of SPs and are well established sources of these particularly interesting molecules such as ulvans from Ulva and Enteromorpha, sulfated rhamnans from Monostroma, sulfated arabinogalactans from Codium, sulfated galacotans from Caulerpa, and some special sulfated mannans from different species. These SPs exhibit many beneficial biological activities such as anticoagulant, antiviral, antioxidative, antitumor, immunomodulating, antihyperlipidemic and antihepatotoxic activities. Therefore, marine algae derived SPs have great potential for further development as healthy food and medical products. The present review focuses on SPs derived from marine green algae and presents an overview of the recent progress of determinations of their structural types and biological activities, especially their potential health benefits. PMID:25257786

Wang, Lingchong; Wang, Xiangyu; Wu, Hao; Liu, Rui

2014-01-01

263

Overview on biological activities and molecular characteristics of sulfated polysaccharides from marine green algae in recent years.  

PubMed

Among the three main divisions of marine macroalgae (Chlorophyta, Phaeophyta and Rhodophyta), marine green algae are valuable sources of structurally diverse bioactive compounds and remain largely unexploited in nutraceutical and pharmaceutical areas. Recently, a great deal of interest has been developed to isolate novel sulfated polysaccharides (SPs) from marine green algae because of their numerous health beneficial effects. Green seaweeds are known to synthesize large quantities of SPs and are well established sources of these particularly interesting molecules such as ulvans from Ulva and Enteromorpha, sulfated rhamnans from Monostroma, sulfated arabinogalactans from Codium, sulfated galacotans from Caulerpa, and some special sulfated mannans from different species. These SPs exhibit many beneficial biological activities such as anticoagulant, antiviral, antioxidative, antitumor, immunomodulating, antihyperlipidemic and antihepatotoxic activities. Therefore, marine algae derived SPs have great potential for further development as healthy food and medical products. The present review focuses on SPs derived from marine green algae and presents an overview of the recent progress of determinations of their structural types and biological activities, especially their potential health benefits. PMID:25257786

Wang, Lingchong; Wang, Xiangyu; Wu, Hao; Liu, Rui

2014-09-01

264

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

265

Phylogenetic Species, Reproductive Mode, and Specificity of the Green Alga Trebouxia Forming Lichens with the Fungal Genus Letharia  

E-print Network

Lichens with the Fungal Genus Letharia Author(s): Scott Kroken and John W. Taylor Source: The Bryologist of the Green Alga Trebouxia Forming Lichens with the Fungal Genus Letharia SCOTTrrKROKEN1 AND JOHN W. TAYLOR2 of the lichenized fungus Letharia are identified as mem- bers of the morphospecies Trebouxia jamesii, based on ITS

California at Berkeley, University of

266

IDENTIFICATION OF A PSYCHROPHILIC GREEN ALGA FROM LAKE BONNEY ANTARCTICA: CHLAMYDOMONAS RAUDENSIS ETTL. (UWO 241) CHLOROPHYCEAE1  

E-print Network

Victoria Land, Antarctica. The lake is 7 km long and 1 km wide at the widest point (Fritsen and Priscu 1999IDENTIFICATION OF A PSYCHROPHILIC GREEN ALGA FROM LAKE BONNEY ANTARCTICA: CHLAMYDOMONAS RAUDENSIS-covered lake, Lake Bonney, Ant- arctica. Here we identify and report the first de- tailed morphological

Priscu, John C.

267

Lineage-specific fragmentation and nuclear relocation of the mitochondrial cox2 gene in chlorophycean green algae (Chlorophyta).  

PubMed

In most eukaryotes the subunit 2 of cytochrome c oxidase (COX2) is encoded in intact mitochondrial genes. Some green algae, however, exhibit split cox2 genes (cox2a and cox2b) encoding two polypeptides (COX2A and COX2B) that form a heterodimeric COX2 subunit. Here, we analyzed the distribution of intact and split cox2 gene sequences in 39 phylogenetically diverse green algae in phylum Chlorophyta obtained from databases (28 sequences from 22 taxa) and from new cox2 data generated in this work (23 sequences from 18 taxa). Our results support previous observations based on a smaller number of taxa, indicating that algae in classes Prasinophyceae, Ulvophyceae, and Trebouxiophyceae contain orthodox, intact mitochondrial cox2 genes. In contrast, all of the algae in Chlorophyceae that we examined exhibited split cox2 genes, and could be separated into two groups: one that has a mitochondrion-localized cox2a gene and a nucleus-localized cox2b gene ("Scenedesmus-like"), and another that has both cox2a and cox2b genes in the nucleus ("Chlamydomonas-like"). The location of the split cox2a and cox2b genes was inferred using five different criteria: differences in amino acid sequences, codon usage (mitochondrial vs. nuclear), codon preference (third position frequencies), presence of nucleotide sequences encoding mitochondrial targeting sequences and presence of spliceosomal introns. Distinct green algae could be grouped according to the form of cox2 gene they contain: intact or fragmented, mitochondrion- or nucleus-localized, and intron-containing or intron-less. We present a model describing the events that led to mitochondrial cox2 gene fragmentation and the independent and sequential migration of cox2a and cox2b genes to the nucleus in chlorophycean green algae. We also suggest that the distribution of the different forms of the cox2 gene provides important insights into the phylogenetic relationships among major groups of Chlorophyceae. PMID:22724135

Rodríguez-Salinas, Elizabeth; Riveros-Rosas, Héctor; Li, Zhongkui; Fucíková, Karolina; Brand, Jerry J; Lewis, Louise A; González-Halphen, Diego

2012-07-01

268

[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

269

[Cellular response of freshwater green algae to the toxicity of tetracycline antibiotics].  

PubMed

Tetracycline antibiotics are a group of antibiotics which has been extensively used in most countries and are also the most widely used veterinary drugs and food additives in aquaculture and livestock industries of China. Because the substances are poorly adsorbed in the gut of animals and are only partially eliminated in sewage treatment plants, the antibiotics and their metabolites reach surface water where they may affect the aquatic organisms and human health. Herein, using green algae as test organisms, we studied the effects of tetracycline (TC), chlortetracycline (CTC) and deoxyteracycline (DC) on the cell permeability and growth inhibition of chlorella pyrenoidosa and scenedesmus obliquus. After 96 h of antibiotics exposure, the permeability of the cell membranes of both algae was decreased in the entire concentration range of doxycycline and was increased after exposure to a low concentration of tetracycline and chlortetracycline, then was decreased with the increase of the two antibiotics concentrations. The growth inhibiting effects of these three antibiotics on chlorella pyrenoidosa and scenedesmus obliquus were in an order of DC > TC > CTC. The ecotoxic response of scenedesmus obliquus to tetracycline antibiotics was more sensitive than chlorella pyrenoidosa. PMID:24288980

Xu, Dong-mei; Wang, Yan-hua; Rao, Gui-wei

2013-09-01

270

Genotoxic effects of commercial formulations of Chlorpyrifos and Tebuconazole on green algae.  

PubMed

The alkaline single-cell gel electrophoresis assay (comet assay) was used for the study of the genotoxic effects of insecticide Chlorpyrifos and fungicide Tebuconazole (commercial formulations) on two freshwater green algae species, Pseudokirchneriella subcapitata and Nannocloris oculata, after 24 h of exposure. The percentage of DNA in tail of migrating nucleoids was taken as an endpoint of DNA impairment. Cell viability was measured by fluorometric detection of chlorophyll "a" in vivo and the determination of cell auto-fluorescence. Only the higher concentration of Chlorpyrifos tested resulted to affect significantly the cell viability of P. subcapitata, whereas cells of N. oculata were not affected. Tebuconazole assayed concentrations (3 and 6 mg/l) did not affect cell viability of both species. The results of comet assay on P. subcapitata showed that Chlorpyrifos concentration evaluated (0.8 mg/l) exerted a genotoxic effects; while for the other specie a concentration of 10 mg/l was needed. Tebuconazole was genotoxic at 3 and 6 mg/l for both species. The comet assay evidenced damage at the level of DNA simple strains molecule at pesticide concentrations were cytotoxicity was not evident, demonstrating that algae are models to take into account in ecological risk assessments for aquatic environments. PMID:25230876

Martinez, Ricardo Santiago; Di Marzio, Walter Darío; Sáenz, María Elena

2015-01-01

271

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. PMID:10049347

Braun, F J; Hegemann, P

1999-01-01

272

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

273

Catalytic pyrolysis of green algae for hydrocarbon production using H+ZSM-5 catalyst.  

PubMed

Microalgae are considered as an intriguing candidate for biofuel production due to their high biomass yield. Studies on bio-oil production through fast pyrolysis and upgrading to hydrocarbon fuels using algal biomass are limited as compared to other terrestrial biomass. Therefore, in this study, a fresh water green alga, Chlorella vulgaris, was taken for pyrolysis study. The average activation energy for pyrolysis zone was found to be 109.1 kJ/mol. Fixed-bed pyrolysis of algae gave a bio-oil yield of 52.7 wt.%, which accounts for 60.7 wt.% carbon yield. In addition, analytical pyrolysis of C. vulgaris was carried out in a Py/GC-MS to identify major compounds present in bio-oil with and without catalyst (H(+)ZSM-5). The study found that in catalytic-pyrolysis, as the catalyst loading increased from zero to nine times of the biomass, the carbon yield of aromatic hydrocarbons increased from 0.9 to 25.8 wt.%. PMID:22705518

Thangalazhy-Gopakumar, Suchithra; Adhikari, Sushil; Chattanathan, Shyamsundar Ayalur; Gupta, Ram B

2012-08-01

274

State 1-State 2 Transitions in a Unicellular Green Algae 1  

PubMed Central

A study has been made on the State 1-State 2 transitions exhibited by the unicellular green algae Chlorella pyrenoidosa. Chlorophyll fluorescence induction curves from algae adapted to State 1 or State 2 have been analyzed and a comparison made with similar curves produced by decreasing the intensity of light going to the photosystem II reaction centers. In both cases, quenching of the maximum fluorescence yield (Fm) and the initial fluorescence yield (Fo) were observed so that the Fv/Fm ratio and the area above the induction curve (Amax) remained constant. The State 1-State 2 transition also produced changes in the ?max component indicative of some alteration within photosystem II organization. The implications of these experiments on the in vivo mechanism for energy redistribution between the two photosystems are discussed in terms of changes in absorption cross-section rather than being due to spillover from photosystem II to photosystem I. These changes may reflect the phosphorylation of the light-harvesting chlorophyll a/b protein complex and its subsequent migration away from the photosystem II core leading to its closer association with photosystem I. PMID:16663130

Hodges, Michael; Barber, James

1983-01-01

275

Ketocarotenoid biosynthesis outside of plastids in the unicellular green alga Haematococcus pluvialis.  

PubMed

The carotenoid biosynthetic pathway in algae and plants takes place within plastids. In these organelles, carotenoids occur either in a free form or bound to proteins. Under stress, the unicellular green alga Haematococcus pluvialis accumulates secondary carotenoids, mainly astaxanthin esters, in cytoplasmic lipid vesicles up to 4% of its dry mass. It is therefore one of the favored organisms for the biotechnological production of these antioxidative compounds. We have studied the cellular localization and regulation of the enzyme beta-carotene oxygenase in H. pluvialis that catalyzes the introduction of keto functions at position C-4 of the beta-ionone ring of beta-carotene and zeaxanthin. Using immunogold labeling of ultrathin sections and Western blot analysis of cell fractions, we discovered that under inductive conditions, beta-carotene oxygenase was localized both in the chloroplast and in the cytoplasmic lipid vesicles, which are (according to their lipid composition) derived from cytoplasmic membranes. However, beta-carotene oxygenase activity was confined to the lipid vesicle compartment. Because an early carotenogenic enzyme in the pathway, phytoene desaturase, was found only in the chloroplast (Grünewald, K., Eckert, M., Hirschberg, J., and Hagen, C. (2000) Plant Physiol. 122, 1261-1268), a transport of intermediates from the site of early biosynthetic steps in the chloroplast to the site of oxygenation and accumulation in cytoplasmic lipid vesicles is proposed. PMID:11085982

Grünewald, K; Hirschberg, J; Hagen, C

2001-02-23

276

A diverse assemblage of indole-3-acetic acid producing bacteria associate with unicellular green algae.  

PubMed

Microalgae have tremendous potential as a renewable feedstock for the production of liquid transportation fuels. In natural waters, the importance of physical associations and biochemical interactions between microalgae and bacteria is generally well appreciated, but the significance of these interactions to algal biofuels production have not been investigated. Here, we provide a preliminary report on the frequency of co-occurrence between indole-3-acetic acid (IAA)-producing bacteria and green algae in natural and engineered ecosystems. Growth experiments with unicellular algae, Chlorella and Scenedesmus, revealed IAA concentration-dependent responses in chlorophyll content and dry weight. Importantly, discrete concentrations of IAA resulted in cell culture synchronization, suggesting that biochemical priming of cellular metabolism could vastly improve the reliability of high density cultivation. Bacterial interactions may have an important influence on algal growth and development; thus, the preservation or engineered construction of the algal-bacterial assembly could serve as a control point for achieving low input, reliable production of algal biofuels. PMID:24879600

Bagwell, Christopher E; Piskorska, Magdalena; Soule, Tanya; Petelos, Angela; Yeager, Chris M

2014-08-01

277

Effect of nitrite and nitrate on chlorophyll fluorescence in green algae.  

PubMed

The influence of nitrite and nitrate on chlorophyll fluorescence, a very sensitive indicator for the redox state of the primary acceptor of photosystem II of photosynthesis, was studied in green algae (several species of Chlorella, and Ankistrodesmus braunii). In phosphate solution under an atmosphere of nitrogen (i.e., in the absence of O2 and CO2, and without nitrite or nitrate), fluorescence shows a pronounced induction and then rises to a high steady-state level. In the presence of nitrite, however, fluorescence decreases after a rather short induction peak to a much lower steady-state. Nitrate, on the other hand, does not have any influence on either induction or steady-state of fluorescence. These results clearly demonstrate that nitrite reduction in the light is very closely coupled to the photosynthetic electron transport system, whereas nitrate is not reduced photosynthetically in vivo. PMID:24469416

Kessler, E; Zumft, W G

1973-03-01

278

Blue green alga mediated synthesis of gold nanoparticles and its antibacterial efficacy against Gram positive organisms.  

PubMed

Biofunctionalized gold nanoparticles (AuNPs) play an important role in design and development of nanomedicine. Synthesis of AuNPs from biogenic materials is environmentally benign and possesses high bacterial inhibition and bactericidal properties. In the present study, blue green alga Spirulina platensis protein mediated synthesis of AuNPs and its antibacterial activity against Gram positive bacteria is discussed. AuNPs were characterized using Ultraviolet-visible (UV-vis) spectroscopy, Fluorescence spectroscopy, Fourier Transform-Infrared (FTIR) spectroscopy, Raman spectroscopy, High Resolution-Transmission Electron Microscopy (HR-TEM) and Energy Dispersive X-ray analysis (EDAX). Stable, well defined AuNPs of smaller and uniform shape with an average size of ~ 5 nm were obtained. The antibacterial efficacy of protein functionalized AuNPs were tested against Gram positive organisms Bacillus subtilis and Staphylococcus aureus. PMID:25492207

Suganya, K S Uma; Govindaraju, K; Kumar, V Ganesh; Dhas, T Stalin; Karthick, V; Singaravelu, G; Elanchezhiyan, M

2015-02-01

279

Regulatory effect of hydrogen on nitrogenase activity of the blue-green alga (cyanobacterium) Nostoc muscorum.  

PubMed

Preincubation of the blue-green alga (cyanobacterium) Nostoc muscorum under an atmosphere of argon plus acetylene in the light led to a greater than fourfold increase of light-induced hydrogen evolution and to a 50% increase of acetylene reduction, as compared to cells that had not been preconditioned. The basic and the increased hydrogen evolution were both due to nitrogenase activity. Furthermore, after preincubation the hydrogen uptake, usually observed with unconditional cells, was abolished. Nostoc preincubated under acetylene evolved hydrogen in the light even in the presence of nitrogen for at least 2 h, with a 15-fold increase as compared to the unconditioned cells. These acetylene effects could be completely abolished by the presence of hydrogen during acetylene preincubation. These findings indicate that the hydrogen concentration in N. muscorum cells plays a role in regulation of nitrogenase activity. PMID:6767700

Scherer, S; Kerfin, W; Böger, P

1980-03-01

280

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

281

Study of photosystem 2 heterogeneity in the sulfur-deficient green alga Chlamydomonas reinhardtii.  

PubMed

A set of chlorophyll fluorescence methods, including PEA (Plant Efficiency Analyser), PAM (Pulse Amplitude Modulated fluorometer), and picosecond fluorometer, was employed to study PS 2 heterogeneity in sulfur deprived green algae Chlamydomonas reinhardtii. The regression method and JIP test were applied to analyze chlorophyll fluorescence kinetics. The fractions of PS 2 characterized by the energetic disconnection, smaller antenna size, elevated constant rate of primary photochemistry, and inability to maintain DeltapH-dependent energy dissipation increased essentially already after 12 h of incubation in sulfur depleted medium. The amount of PS 2 centers with reduced QA (closed state), QB-non-reducing centers with impaired water splitting function, and centers coupled to the plastoquinone pool with the slow cycle rate increased dramatically after 24 h period of deprivation. The mechanisms of PS 2 inactivation under sulfur deprivation are discussed. PMID:17701284

Antal, Taras K; Krendeleva, Tatyana E; Rubin, Andrew B

2007-10-01

282

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

283

Anaerobic Metabolism in the N-Limited Green Alga Selenastrum minutum1  

PubMed Central

We have determined the flow of 15N into free amino acids of the N-limited green alga Selenastrum minutum (Naeg.) Collins after addition of 15NH4+ to aerobic or anaerobic cells. Under aerobic conditions, only a small proportion of the N assimilated was retained in the free amino acid pool. However, under anaerobic conditions almost all assimilated NH4+ accumulates in alanine. This is a unique feature of anaerobic NH4+ assimilation. The pathway of carbon flow to alanine results in the production of ATP and reductant which matches exactly the requirements of NH4+ assimilation. Alanine synthesis is therefore an excellent strategy to maintain energy and redox balance during anaerobic NH4+ assimilation. PMID:16668034

Vanlerberghe, Greg C.; Joy, Kenneth W.; Turpin, David H.

1991-01-01

284

Predictive modeling studies for the ecotoxicity of ionic liquids towards the green algae Scenedesmus vacuolatus.  

PubMed

Hazardous potential of ionic liquids is becoming an issue of high concern with increasing application of these compounds in various industrial processes. Predictive toxicological modeling on ionic liquids provides a rational assessment strategy and aids in developing suitable guidance for designing novel analogues. The present study attempts to explore the chemical features of ionic liquids responsible for their ecotoxicity towards the green algae Scenedesmus vacuolatus by developing mathematical models using extended topochemical atom (ETA) indices along with other categories of chemical descriptors. The entire study has been conducted with reference to the OECD guidelines for QSAR model development using predictive classification and regression modeling strategies. The best models from both the analyses showed that ecotoxicity of ionic liquids can be decreased by reducing chain length of cationic substituents and increasing hydrogen bond donor feature in cations, and replacing bulky unsaturated anions with simple saturated moiety having less lipophilic heteroatoms. PMID:24296027

Das, Rudra Narayan; Roy, Kunal

2014-06-01

285

Vesicular trafficking in characean green algae and the possible involvement of a VAMP72-family protein  

PubMed Central

The RAB5 GTPase ARA6 of Arabidopsis thaliana is known to be involved in endosomal trafficking by targeting vesicles to the plasma membrane. During this process AtARA6 is working in close relationship with the SNARE protein VAMP727 (vesicle associated membrane protein 727). Recently, ARA6 of the characean green algae Chara australis (CaARA6) was shown to have properties similar to AtARA6, pointing to similar trafficking pathways. In order to gain further insight into the vesicle trafficking machinery of Characeae, C. australis was analyzed for homologous proteins of the VAMP72-family. A CaVAMP72 protein was detected and classified by protein sequence alignment and phylogenetic analyses. PMID:24614164

Hoepflinger, Marion C; Hametner, Christina; Ueda, Takashi; Foissner, Ilse

2014-01-01

286

Development of suitable photobioreactors for CO2 sequestration addressing global warming using green algae and cyanobacteria.  

PubMed

CO(2) sequestration by cyanobacteria and green algae are receiving increased attention in alleviating the impact of increasing CO(2) in the atmosphere. They, in addition to CO(2) capture, can produce renewable energy carriers such as carbon free energy hydrogen, bioethanol, biodiesel and other valuable biomolecules. Biological fixation of CO(2) are greatly affected by the characteristics of the microbial strains, their tolerance to temperature and the CO(2) present in the flue gas including SO(X), NO(X). However, there are additional factors like the availability of light, pH, O(2) removal, suitable design of the photobioreactor, culture density and the proper agitation of the reactor that will affect significantly the CO(2) sequestration process. Present paper deals with the photobioreactors of different geometry available for biomass production. It also focuses on the hybrid types of reactors (integrating two reactors) which can be used for overcoming the bottlenecks of a single photobioreactor. PMID:21334885

Kumar, Kanhaiya; Dasgupta, Chitralekha Nag; Nayak, Bikram; Lindblad, Peter; Das, Debabrata

2011-04-01

287

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

288

Green and blue-light-mediated chloroplast migration in the centric diatom Pleurosira laevis  

Microsoft Academic Search

Summary The existence of two photoreceptors regulating chloroplast orientation was found in the centric diatomPleurosira laevis. Chloroplasts migrate through the transvacuolar cytoplasmic strands according to the light conditions. Weak white light of less than 46 µmol\\/m2 · s (10 W\\/m2) induces chloroplast movement to the cortical cytoplasm, which is located next to the plasma membrane (dispersion), while intense white light

T. Furukawa; M. Watanabe; I. Shihira-Ishikawa

1998-01-01

289

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

290

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. PMID:24533922

2014-01-01

291

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. PMID:21048801

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

2011-01-01

292

Environmental monitoring of heavy metals in Bulgarian Black Sea green algae.  

PubMed

Fe, Mn, Cu, Pb and Cd concentration distribution in six green macroalgae species from the Bulgarian Black Sea coast were determined. The measurement of these metals was carried out during six seasons from 1996 to 2002 using atomic absorption spectrometry (AAS). Samples were collected from eight different sites-Shabla, Kaliakra, Tuzlata, Ravda, Ahtopol and Sinemoretz. The obtained heavy metal (HM) data (mean values microg/g) for all algae are: 650 +/- 100 for Fe, 184 +/- 15 for Mn, 5.6 +/- 0.5 for Cu, 3.3 +/- 0.3 for Pb and 1.1 +/- 0.2 for Cd. The obtained HM contents indicate that different species demonstrate various degree of metal accumulation and the obtained higher values in the northern sector of the studied zone can be attributed to the discharge influence of the big rivers, entering the Black Sea-Danube, Dnyepr, Dnester and local pollutant emissions. All data show that there is no serious contamination in green macroalgae with heavy and toxic metals along the whole Bulgarian Black Sea coast. PMID:15952514

Strezov, Alexander; Nonova, Tzvetana

2005-06-01

293

Enzymes Related to Lactate Metabolism in Green Algae and Lower Land Plants 1  

PubMed Central

Cell-free extracts of Chlorella pyrenoidosa contained two enzymes capable of oxidizing d-lactate; these were glycolate dehydrogenase and NAD+-dependent d-lactate dehydrogenase. The two enzymes could be distinguished by differential centrifugation, glycolate dehydrogenase being largely particulate and NAD+-d-lactate dehydrogenase being soluble. The reduction of pyruvate by NADH proceeded more rapidly than the reverse reaction, and the apparent Michaelis constants for pyruvate and NADH were lower than for d-lactate and NAD+. These data indicated that under physiological conditions, the NAD+-linked d-lactate dehydrogenase probably functions to produce d-lactate from pyruvate. Lactate dehydrogenase activity dependent on NAD+ was found in a number of other green algae and in the green tissues of a few lower land plants. When present in species which contain glycolate oxidase rather than glycolate dehydrogenase, the enzyme was specific for l-lactate rather than d-lactate. A cyclic system revolving around the production and utilization of d-lactate in some species and l-lactate in certain others is proposed. PMID:16658670

Gruber, Peter J.; Frederick, Sue Ellen; Tolbert, N. E.

1974-01-01

294

[In vitro repair of gamma-irradiated transforming Bacillus subtilis DNA by extracts of blue-green algae].  

PubMed

A cell-free extract from blue-green alga Anacystis nidulans contains enzymes which repair in vitro the transforming activity of gamma-irradiated Bacillus subtilis DNA. The level of restoration of the transforming activity depends on the protein concentration in the reaction mixture, the duration of incubation and on the dose of irradiation. The repair of gamma-induced lesions is most efficient in the presence of magnesium ions, NAD and ATP. The present data indicate that the repair of transforming DNA is performed with the participation of DNA polymerase and polynucleotide ligase which function in the cell-free extract of algae. PMID:6806146

Shevchenko, T N; Gushcha, N I; Dmitriev, A P; Grodzinski?, D M

1982-04-01

295

Foreign gene recruitment to the fatty acid biosynthesis pathway in diatoms.  

PubMed

Diatoms are highly successful marine and freshwater algae that contribute up to 20% of global carbon fixation. These species are leading candidates for biofuel production owing to ease of culturing and high fatty acid content. To assist in strain improvement and downstream applications for potential use as a biofuel, it is important to understand the evolution of lipid biosynthesis in diatoms. The evolutionary history of diatoms is however complicated by likely multiple endosymbioses involving the capture of foreign cells and horizontal gene transfer into the host genome. Using a phylogenomic approach, we assessed the evolutionary history of 12 diatom genes putatively encoding functions related to lipid biosynthesis. We found evidence of gene transfer likely from a green algal source for seven of these genes, with the remaining showing either vertical inheritance or evolutionary histories too complicated to interpret given current genome data. The functions of horizontally transferred genes encompass all aspects of lipid biosynthesis (initiation, biosynthesis, and desaturation of fatty acids) as well as fatty acid elongation, and are not restricted to plastid-targeted proteins. Our findings demonstrate that the transfer, duplication, and subfunctionalization of genes were key steps in the evolution of lipid biosynthesis in diatoms and other photosynthetic eukaryotes. This target pathway for biofuel research is highly chimeric and surprisingly, our results suggest that research done on related genes in green algae may have application to diatom models. PMID:24404416

Chan, Cheong Xin; Baglivi, Francesca L; Jenkins, Christina E; Bhattacharya, Debashish

2013-09-01

296

Diatom Communities and Metrics as Indicators of Urbanization Effects on Streams and Potential Moderation by Landscape Green Infrastructure  

EPA Science Inventory

Diatoms are very useful and important indicators of anthropogenic impacts on streams because they are the foundation of primary production and are responsive to nutrients, conductivity, and habitat conditions. We characterized relationships of diatom assemblages with water chemis...

297

Evaluation of toxicity data to green algae and relationship with hydrophobicity.  

PubMed

The quality of the biological activity data is of great importance for the development of algal quantitative structure-activity relationship (QSAR) models. However, a number of algal QSAR models in the literature were developed based on toxicity data without considering the response endpoints, exposure periods and species sensitivity. In this paper, 2323 algal toxicity data (log 1/EC50) in different toxicity response endpoints for 1081 compounds to 26 algal species within different exposure periods (14 and 15 min; 24, 48, 72, 96, 168 and 192 h) were used to evaluate the quality of the toxicity data to green algae. Analysis of 72 h toxicity to algae showed that the closed test had the same sensitivity as the open test for most of the test compounds, but a significant difference was observed for a few compounds. The overall average difference for all compounds ranges from 0.15 to 0.43 log units between toxicity endpoints (yield–growth rate). The relationships between exposure periods of 24, 48, 72 and 96 h indicated that 48 h exposure period is the most sensitive for algal growth inhibition test, and its sensitivity is 0.25 log units greater than 72 and 96 h exposure periods, respectively. Interspecies relationships showed that some algal species have very close sensitivity (e.g. Pseudokirchneriella subcapitata and Chlorella pyrenoidosa or Chlorella vulgaris and Scenedesmus obliquus, respectively), whereas some species have significantly different sensitivity (e.g. P. subcapitata and S. obliquus). Relationships between toxicity and hydrophobicity demonstrated that no difference was observed for non-polar narcotics within different exposure periods (24, 48, 72, and 96 h) or response variables (yield and growth rate). For polar narcotics, in contrast, algal toxicity is dependent on algal species and is related to the response variables and exposure period. We cannot expect significant QSAR models between algal toxicity and descriptors without considering species sensitivity, exposure periods and response endpoints. PMID:25462296

Fu, Ling; Li, Jin J; Wang, Yu; Wang, Xiao H; Wen, Yang; Qun, Wei C; Su, Li M; Zhao, Yuan H

2015-02-01

298

Diatom Genomics: Genetic Acquisitions and Mergers  

E-print Network

Diatom Genomics: Genetic Acquisitions and Mergers Dispatch R. Ellen R. Nisbet, Oliver Kilian and Geoffrey I. McFadden Diatom algae arose by two-step endosymbiosis. The complete genome of the diatom. They comman- deer your intellectual property, relocate it to head office, and -- to add insult to injury

McFadden, Geoff

299

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

300

Insights into intrathalline genetic diversity of the cosmopolitan lichen symbiotic green alga Trebouxia decolorans Ahmadjian using microsatellite markers.  

PubMed

Trebouxia decolorans is a widespread and common symbiotic green alga that is found in association with different species of lichen-forming fungi. By applying T. decolorans-specific microsatellite markers, we investigated the within-thallus diversity of T. decolorans in thalli of Xanthoria parietina and Anaptychia ciliaris. We found several algal strains in most of the thalli of both hosts. High genetic differentiation among thalli suggests that algal diversity is generated de novo via mutation in both fungal hosts. Rarefied allelic richness of the algae was higher in thalli of X. parietina. Our results indicate that in X. parietina intrathalline algal diversity is additionally created by environmental uptake of algae either at the start of the symbiotic association or during the lifetime of the thallus. This study indicates that promiscuous host-symbiont associations in lichen symbioses with Trebouxia spp. may be more common than currently recognized. PMID:24412431

Dal Grande, Francesco; Alors, David; Divakar, Pradeep K; Bálint, Miklós; Crespo, Ana; Schmitt, Imke

2014-03-01

301

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

302

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

303

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

304

Hydrogen metabolism of green algae: discovery and early research – a tribute to Hans Gaffron and his coworkers  

Microsoft Academic Search

The detection of hydrogen metabolism in green algae more than 60 years ago by Hans Gaffron dispelled the widely accepted dogma\\u000a at that time that this feature was unique to prokaryotic organisms. Research on this unexpected aspect of algal physiology\\u000a has continued until today because of its evolutionary implications and possible practical significance. This minireview focuses\\u000a on the work of

Peter H. Homann

2003-01-01

305

Zoosporangia survival, dehiscence and zoospore formation, and motility in the green alga Rhizoclonium hieroglyphicum as affected by different factors  

Microsoft Academic Search

Urea at 200 ppm (probably serving as a nitrogen source), liquid Bold’s basal medium at pH 7.5, temperature of about 22 °C\\u000a and light intensity of about 40 µmol m?2 s?1 for 16 h a day induced rapid and\\/or abundant zoospores formation and zoosporangia dehiscence and favored zoospore liberation,\\u000a speed and motility time period in the green algaRhizoclonium hieroglyphicum. However,

S. Gupta; S. C. Agrawai

2004-01-01

306

Evidence for chemical defense in tropical green alga Caulerpa ashmeadii (Caulerpaceae: Chlorophyta): Isolation of new bioactive sesquiterpenoids  

Microsoft Academic Search

Results of field feeding preference studies with 12 species of tropical green algae of the genusCaulerpa showed thatC. ashmeadii was preferred least by herbivorous fishes. Chemical investigations ofC. ashmeadii demonstrated the presence of high concentrations of sesquiterpenoid metabolites. The chemical isolation and structural elucidation of five majorC. ashmeadii metabolites, as well as the results of field feeding preference, antimicrobial, and

Valerie J. Paul; Mark M. Littler; Diane S. Littler; William Fenical

1987-01-01

307

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

308

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

309

Ultrahigh-cell-density culture of a marine green alga Chlorococcum littorale in a flat-plate photobioreactor  

Microsoft Academic Search

To test the feasibility of CO2 remediation by microalgal photosynthesis, a modified type of flat-plate photobioreactor [Hu et al. (1996) Biotechnol Bioeng 51:51–60] has been designed for cultivation of a high-CO2-tolerant unicellular green alga Chlorococcum littorale. The modified reactor has a narrow light path in which intensive turbulent flow is provided by streaming compressed air through\\u000a perforated tubing into the

Q. Hu; N. Kurano; M. Kawachi; I. Iwasaki; S. Miyachi

1998-01-01

310

Production of cell wall polypeptides by different cell wall mutants of the unicellular green alga Chlamydomonas reinhardtii  

Microsoft Academic Search

Three classes of cell wall-defective mutants of the unicellular green alga Chlamydomonas reinhardtii have been described in the literature differing with respect to the amounts of cell wall material and its attachment to the plasma membrane, respectively. We have compared the production of the chaotrope-soluble cell wall polypeptides by the different mutants. These experiments have been performed by comparative Western-blot

Jürgen Voigt; Bettina Hinkelmann; Elizabeth H. Harris

1997-01-01

311

Biosorption of Pb(II) and Cd(II) from aqueous solution using green alga ( Ulva lactuca) biomass  

Microsoft Academic Search

The biosorption characteristics of Pb(II) and Cd(II) ions from aqueous solution using the green alga (Ulva lactuca) biomass were investigated as a function of pH, biomass dosage, contact time, and temperature. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were applied to describe the biosorption isotherm of the metal ions by U. lactuca biomass. Langmuir model fitted the equilibrium data better than

Ahmet Sar?; Mustafa Tuzen

2008-01-01

312

Growth Stimulation and Inhibition Effects of 4-Hydroxybenzoic Acid and Some Related Compounds on the Freshwater Green Alga Pseudokirchneriella subcapitata  

Microsoft Academic Search

4-Hydroxybenzoic acid (4-HBA) exhibited low algal toxicity with the 72-h median inhibition concentration (IC50) of 9.9 mmol\\/L in the standard growth inhibition test using the freshwater green alga Pseudokirchneriella subcapitata. In contrast, it stimulated the algal growth at lower concentrations ranging from 0.1 to 1.0 mmol\\/L. Comparative studies\\u000a with benzoic acid and 2- and 3-hydroxybenzoic acids (2-HBA and 3-HBA) indicated

Y. Kamaya; S. Tsuboi; T. Takada; K. Suzuki

2006-01-01

313

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

314

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. PMID:23940100

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

2013-01-01

315

Occurrence of Only One Form of Glutamine Synthetase in the Green Alga Monoraphidium braunii.  

PubMed Central

Anion-exchange chromatography of crude extracts from the green alga Monoraphidium braunii yielded two glutamine synthetase (GS) activities. The ratio of activities was markedly different when crude extracts were subjected to various processing conditions but was not influenced by environmental factors of cell cultures. However, high performance liquid chromatography anion-exchange chromatograms showed only one GS if the crude extracts were processed immediately after cell disruption. Moreover, standard chromatography of crude extracts obtained in the absence of dithioerythritol, a reductant generally used in disruption buffers, yielded a single activity peak. Enzyme samples from the two activities obtained in the presence of dithioerythritol were purified for physicochemical characterization and antibody production. Both enzyme samples exhibited similar reactions to different inactivating agents and were undistinguishable by size-exclusion chromatography and native polyacrylamide gel electrophoresis. Additionally, the two GS preparations showed absolute antigenic identity as demonstrated by immunodiffusion and immunoblotting experiments. Immunocytochemistry of M. braunii cryosections evidenced a chloroplast-specific distribution of the enzyme, which rules out the existence of a cytoplasmic counterpart. All these results support the proposal that M. braunii possesses only one form of GS. PMID:12232093

Garcia-Fernandez, J. M.; Lopez-Ruiz, A.; Toribio, F.; Roldan, J. M.; Diez, J.

1994-01-01

316

Genome of the halotolerant green alga Picochlorum sp. reveals strategies for thriving under fluctuating environmental conditions.  

PubMed

An expected outcome of climate change is intensification of the global water cycle, which magnifies surface water fluxes, and consequently alters salinity patterns. It is therefore important to understand the adaptations and limits of microalgae to survive changing salinities. To this end, we sequenced the 13.5?Mbp genome of the halotolerant green alga Picochlorum?SENEW3 (SE3) that was isolated from a brackish water pond subject to large seasonal salinity fluctuations. Picochlorum?SE3 encodes 7367 genes, making it one of the smallest and most gene dense eukaryotic genomes known. Comparison with the pico-prasinophyte Ostreococcus tauri, a species with a limited range of salt tolerance, reveals the enrichment of transporters putatively involved in the salt stress response in Picochlorum?SE3. Analysis of cultures and the protein complement highlight the metabolic flexibility of Picochlorum?SE3 that encodes genes involved in urea metabolism, acetate assimilation and fermentation, acetoin production and glucose uptake, many of which form functional gene clusters. Twenty-four cases of horizontal gene transfer from bacterial sources were found in Picochlorum?SE3 with these genes involved in stress adaptation including osmolyte production and growth promotion. Our results identify Picochlorum?SE3 as a model for understanding microalgal adaptation to stressful, fluctuating environments. PMID:24965277

Foflonker, Fatima; Price, Dana C; Qiu, Huan; Palenik, Brian; Wang, Shuyi; Bhattacharya, Debashish

2015-02-01

317

Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae.  

PubMed

Trace metals play important roles in normal and in disease-causing biological functions. X-ray fluorescence microscopy reveals trace elements with no dependence on binding affinities (unlike with visible light fluorophores) and with improved sensitivity relative to electron probes. However, X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular material. Here we show that X-ray ptychography can be combined with fluorescence to image both cellular structure and trace element distribution in frozen-hydrated cells at cryogenic temperatures, with high structural and chemical fidelity. Ptychographic reconstruction algorithms deliver phase and absorption contrast images at a resolution beyond that of the illuminating lens or beam size. Using 5.2-keV X-rays, we have obtained sub-30-nm resolution structural images and ?90-nm-resolution fluorescence images of several elements in frozen-hydrated green algae. This combined approach offers a way to study the role of trace elements in their structural context. PMID:25675478

Deng, Junjing; Vine, David J; Chen, Si; Nashed, Youssef S G; Jin, Qiaoling; Phillips, Nicholas W; Peterka, Tom; Ross, Rob; Vogt, Stefan; Jacobsen, Chris J

2015-02-24

318

Effects of lead on tolerance, bioaccumulation, and antioxidative defense system of green algae, Cladophora.  

PubMed

Effects of various concentrations (0.5, 1.0, 2.5, 5.0, 7.5, and 10.0 mg/L) of lead (Pb(2+)) on the growth, bioaccumulation, and antioxidative defense system of green algae, Cladophora, was investigated. Low concentrations of Pb(2+) accelerated Cladophora growth, but concentrations of 10.0 mg/L and above inhibited the growth because of the hinderance to photosynthesis. The total soluble sugar content of Cladophora was affected by Pb(2+) treatment, but the protein content showed no significant changes. The malondialdehyde (MDA) content and peroxidase(POD) activity of Cladophora gradually increased whereas superoxide dismutase(SOD) decreased with Pb(2+) concentrations. Catalase (CAT) activity exhibited no significant changes following Pb(2+) treatment. Pb(2+) accumulated in Cladophora and that the lead content in Cladophora was correlated with POD growth, MDA, and Metallothionein (MT). POD and MT play a role in the survival of Cladophora in Pb-contaminated environments. This study suggests that Cladophora can be a choice organism for the phytoremediation of Pb-polluted coastal areas. PMID:25463875

Cao, De-ju; Shi, Xiao-dong; Li, Hao; Xie, Pan-pan; Zhang, Hui-min; Deng, Juan-wei; Liang, Yue-gan

2015-02-01

319

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

320

Simultaneous cryo X-ray ptychographic and fluorescence microscopy of green algae  

PubMed Central

Trace metals play important roles in normal and in disease-causing biological functions. X-ray fluorescence microscopy reveals trace elements with no dependence on binding affinities (unlike with visible light fluorophores) and with improved sensitivity relative to electron probes. However, X-ray fluorescence is not very sensitive for showing the light elements that comprise the majority of cellular material. Here we show that X-ray ptychography can be combined with fluorescence to image both cellular structure and trace element distribution in frozen-hydrated cells at cryogenic temperatures, with high structural and chemical fidelity. Ptychographic reconstruction algorithms deliver phase and absorption contrast images at a resolution beyond that of the illuminating lens or beam size. Using 5.2-keV X-rays, we have obtained sub–30-nm resolution structural images and ?90-nm–resolution fluorescence images of several elements in frozen-hydrated green algae. This combined approach offers a way to study the role of trace elements in their structural context. PMID:25675478

Deng, Junjing; Vine, David J.; Chen, Si; Nashed, Youssef S. G.; Jin, Qiaoling; Phillips, Nicholas W.; Peterka, Tom; Ross, Rob; Vogt, Stefan; Jacobsen, Chris J.

2015-01-01

321

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

322

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

323

Assessing the combined effects from two kinds of cephalosporins on green alga (Chlorella pyrenoidosa) based on response surface methodology.  

PubMed

The present work evaluated the combined effects of cefradine and ceftazidime on the green alga Chlorella pyrenoidosa using response surface methodologies (RSM). After a 48?h-exposure, the population growth rate (PGR), the chlorophyll-a content and the SOD content of the alga increased with increased concentrations of two antibiotics. However, the three responses did not continue to demonstrate significant increases once antibiotic concentrations exceed a moderate level. Three two order polynomial regression equations were obtained to describe well the relationship between the responses of the alga and the two antibiotics' concentration (R(2)?=?0.9997, 0.9292 and 0.9039, respectively). Three 3?D-surface graphs and their contour plots showed directly the changing trends of the alga under the combined effects of two antibiotics. This study for the first time employed the RSM in ecotoxicology, which indicated that the RSM should be placed under a feasible and a potential application prospect in toxicity assessment. PMID:25684417

Guo, Ruixin; Xie, Weishu; Chen, Jianqiu

2015-04-01

324

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. PMID:10488235

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

1999-01-01

325

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. PMID:22616009

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

2012-01-01

326

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

327

A rapid, modular and marker-free chloroplast expression system for the green alga Chlamydomonas reinhardtii.  

PubMed

In search of alternative expression platforms heterologous protein production in microalgae has gained increasing importance in the last years. Particularly, the chloroplast of the green alga Chlamydomonas reinhardtii has been adopted to successfully express foreign proteins like vaccines and antibodies. However, when compared with other expression systems, the development of the algal chloroplast to a powerful production platform for recombinant proteins is still in its early stages. In an effort to further improve methods for a reliable and rapid generation of transplastomic Chlamydomonas strains we constructed the key plasmid pMM2 containing the psbA gene and a multiple cloning site for foreign gene insertion. The psbA gene allows a marker-free selection procedure using as a recipient the Fud7 strain of Chlamydomonas, which grows on media containing acetate as a carbon source, but is unable to grow photoautotrophically due to the lack of an intact psbA gene. Biolistic transformation of Fud7 with vectors containing this gene restores photoautotrophic growth and thus permits selection in the light on media without carbon sources and antibiotics. The multiple cloning site with a BsaI recognition sequence allows type IIs restriction enzyme-based modular cloning which rapidly generates new gene constructs without sequences, which could influence the expression and characteristics of the foreign protein. In order to demonstrate the feasibility of this approach, a codon optimized version of the gene for the bacterial protein MPT64 has been integrated into the plastome. Several strains with different promoter/UTR combinations show a stable expression of the HA tagged MPT64 protein in Chlamydomonas chloroplasts. PMID:25554634

Bertalan, Ivo; Munder, Matthias C; Weiß, Caroline; Kopf, Judith; Fischer, Dirk; Johanningmeier, Udo

2015-02-10

328

Chlorovirus: a genus of Phycodnaviridae that infects certain chlorella-like green algae.  

PubMed

SUMMARY Taxonomy: Chlorella viruses are assigned to the family Phycodnaviridae, genus Chlorovirus, and are divided into three species: Chlorella NC64A viruses, Chlorella Pbi viruses and Hydra viridis Chlorella viruses. Chlorella viruses are large, icosahedral, plaque-forming, dsDNA viruses that infect certain unicellular, chlorella-like green algae. The type member is Paramecium bursaria chlorella virus 1 (PBCV-1). Physical properties: Chlorella virus particles are large (molecular weight approximately 1 x 10(9) Da) and complex. The virion of PBCV-1 contains more than 100 different proteins; the major capsid protein, Vp54, comprises approximately 40% of the virus protein. Cryoelectron microscopy and three-dimensional image reconstruction of PBCV-1 virions indicate that the outer glycoprotein-containing capsid shell is icosahedral and surrounds a lipid bilayered membrane. The diameter of the viral capsid ranges from 1650 A along the two- and three-fold axes to 1900 A along the five-fold axis. The virus contains 5040 copies of Vp54, and the triangulation number is 169. The PBCV-1 genome is a linear, 330 744-bp, non-permuted dsDNA with covalently closed hairpin ends. The PBCV-1 genome contains approximately 375 protein-encoding genes and 11 tRNA genes. About 50% of the protein-encoding genes match proteins in the databases. Hosts: Chlorella NC64A and Chlorella Pbi, the hosts for NC64A viruses and Pbi viruses, respectively, are endosymbionts of the protozoan Paramecium bursaria. However, they can be grown in the laboratory free of both the paramecium and the virus. These two chlorella species are hosts to viruses that have been isolated from fresh water collected around the world. The host for hydra chlorella virus, a symbiotic chlorella from Hydra viridis, has not been grown independently of its host; thus the virus can only be obtained from chlorella cells freshly released from hydra. PMID:20565652

Kang, Ming; Dunigan, David D; VAN Etten, James L

2005-05-01

329

Phragmoplast of the green alga Spirogyra is functionally distinct from the higher plant phragmoplast  

PubMed Central

Cytokinesis in the green alga Spirogyra (Zygnemataceae) is characterized by centripetal growth of a septum, which impinges on a persistent, centrifugally expanding telophase spindle, leading to a phragmoplast-like structure of potential phylogenetic significance (Fowke, L. C., and J. D. Pickett-Heaps. 1969. J. Phycol. 5:273-281). Combining fluorescent tagging of the cytoskeleton in situ and video- enhanced differential interference contrast microscopy of live cells, the process of cytokinesis was investigated with emphasis on cytoskeletal reorganization and concomitant redistribution of organelles. Based on a sequence of cytoskeletal arrangements and the effects of cytoskeletal inhibitors thereon, cytokinetic progression could be divided into three functional stages with respect to the contribution of microfilaments (MFs) and microtubules (MTs): (1) Initiation: in early prophase, a cross wall initial was formed independently of MFs and MTs at the presumptive site of wall growth. (2) Septum ingrowth: numerous organelles accumulated at the cross wall initial concomitant with reorganization of the extensive peripheral interphase MF array into a distinct circumferential MF array. This array guided the ingrowing septum until it contacted the expanding interzonal MT array. (3) Cross wall closure: MFs at the growing edge of the septum coaligned with and extended along the interzonal MTs toward the daughter nuclei. Thus, actin-based transportation of small organelles during this third stage occurred, in part, along a scaffold previously deployed in space by MTs. Displacement of the nuclei- associated interzonal MT array by centrifugation and depolymerization of the phragmoplast-like structure showed that the success of cytokinesis at the third stage depends on the interaction of both MF and MT cytoskeletons. Important features of the phragmoplast-like structure in Spirogyra were different from the higher plant phragmoplast: in particular, MFs were responsible for the positioning of organelles at the fusion site, contrary to the proposed role of MTs in the higher plant phragmoplast. PMID:7559758

1995-01-01

330

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

PubMed

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(alpha)(about 63% of the total PSII) containing >250 chlorophyll a/b molecules. The smaller antenna size PSII(beta) 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(gamma). 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. PMID:16667636

Smith, B M; Morrissey, P J; Guenther, J E; Nemson, J A; Harrison, M A; Allen, J F; Melis, A

1990-08-01

331

De-eutrophication of effluent wastewater from fish aquaculture by using marine green alga Ulva pertusa  

NASA Astrophysics Data System (ADS)

The de-eutrophication abilities and characteristics of Ulva pertusa, a marine green alga, were investigated in Qingdao Yihai Hatchery Center from spring to summer in 2005 by analyzing the dynamic changes in NH{4/+}, NO{3/-}, NO{2/-} as well as the total dissolved inorganic nitrogen (DIN). The results show that the effluent wastewater produced by fish aquaculture had typical eutrophication levels with an average of 34.3 ?mol L-1 DIN. This level far exceeded the level IV quality of the national seawater standard and could easily lead to phytoplankton blooms in nature if discarded with no treatment. The de-eutrophication abilities of U. pertusa varied greatly and depended mainly on the original eutrophic level the U. pertusa material was derived from. U. pertusa used to living in low DIN conditions had poor DIN removal abilities, while materials cultured in DIN-enriched seawater showed strong de-eutrophication abilities. In other words, the de-eutrophication ability of U. pertusa was evidently induced by high DIN levels. The de-eutrophication capacity of U. pertusa seemed to also be light dependent, because it was weaker in darkness than under illumination. However, no further improvement in the de-eutrophication capacity of U. pertusa was observed once the light intensity exceeded 300 ?mol M2 S-1. Results of semi-continuous wastewater replacement experiments showed that U. pertusa permanently absorbed nutrients from eutrophicated wastewater at a mean rate of 299 mg/kg fresh weight per day (126 mg/kg DIN during the night, 173 mg/kg in daytime). Based on the above results, engineered de-eutrophication of wastewater by using a U. pertusa filter system seems feasible. The algal quantity required to purify all the eutrophicated outflow wastewater from the Qingdao Yihai Hatchery Center into oligotrophic level I clean seawater was also estimated using the daily discharged wastewater, the average DIN concentration released and the de-eutrophication capacity of U. pertusa.

Liu, Jianguo; Wang, Zengfu; Lin, Wei

2010-03-01

332

Preferential technological and life cycle environmental performance of chitosan flocculation for harvesting of the green algae Neochloris oleoabundans.  

PubMed

Dewatering of the green algae Neochloris oleoabundans by flocculation was investigated for chitosan biopolymer, ferric sulfate, and alum. Chitosan was found to be most effective flocculant, with an optimum dose of 100mg/L algae broth. Zeta potential measurements suggest the mechanism involves both adsorption and charge neutralization processes. Life cycle assessment (LCA) was used to compare the chitosan method to other flocculation methods as well as centrifugation and filtration/chamber press processes. LCA showed that among these techniques, flocculation by chitosan is the least energy intensive and had the lowest impacts across all other categories of environmental impacts. The results are discussed in the overall context of biofuel production from algal biomass. PMID:22853967

Beach, Evan S; Eckelman, Matthew J; Cui, Zheng; Brentner, Laura; Zimmerman, Julie B

2012-10-01

333

Sterol composition of steryl chlorin esters (SCEs) formed through grazing of algae by freshwater crustaceans: relevance to the composition of sedimentary SCEs  

Microsoft Academic Search

In a laboratory experiment, we studied the composition of sterols in steryl chlorin esters (SCEs) egested in fecal pellets of freshwater crustaceans (Daphnia magna and Asellus hilgendorfi) fed on a single green algae (Chlorella, Scendesmus, or Stigeoclonium) or on phytoplankton collected from a shallow pond abundant in diatoms. Both unaltered sterols present in dietary phytoplankton and sterols formed by metabolism

Yuko Soma; Nobuyasu Itoh; Yukinori Tani; Mitsuyuki Soma

2005-01-01

334

Evolutionary relatedness does not predict competition and co-occurrence in natural or experimental communities of green algae.  

PubMed

The competition-relatedness hypothesis (CRH) predicts that the strength of competition is the strongest among closely related species and decreases as species become less related. This hypothesis is based on the assumption that common ancestry causes close relatives to share biological traits that lead to greater ecological similarity. Although intuitively appealing, the extent to which phylogeny can predict competition and co-occurrence among species has only recently been rigorously tested, with mixed results. When studies have failed to support the CRH, critics have pointed out at least three limitations: (i) the use of data poor phylogenies that provide inaccurate estimates of species relatedness, (ii) the use of inappropriate statistical models that fail to detect relationships between relatedness and species interactions amidst nonlinearities and heteroskedastic variances, and (iii) overly simplified laboratory conditions that fail to allow eco-evolutionary relationships to emerge. Here, we address these limitations and find they do not explain why evolutionary relatedness fails to predict the strength of species interactions or probabilities of coexistence among freshwater green algae. First, we construct a new data-rich, transcriptome-based phylogeny of common freshwater green algae that are commonly cultured and used for laboratory experiments. Using this new phylogeny, we re-analyse ecological data from three previously published laboratory experiments. After accounting for the possibility of nonlinearities and heterogeneity of variances across levels of relatedness, we find no relationship between phylogenetic distance and ecological traits. In addition, we show that communities of North American green algae are randomly composed with respect to their evolutionary relationships in 99% of 1077 lakes spanning the continental United States. Together, these analyses result in one of the most comprehensive case studies of how evolutionary history influences species interactions and community assembly in both natural and experimental systems. Our results challenge the generality of the CRH and suggest it may be time to re-evaluate the validity and assumptions of this hypothesis. PMID:25473009

Alexandrou, Markos A; Cardinale, Bradley J; Hall, John D; Delwiche, Charles F; Fritschie, Keith; Narwani, Anita; Venail, Patrick A; Bentlage, Bastian; Pankey, M Sabrina; Oakley, Todd H

2015-01-22

335

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

336

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

337

Complex group-I introns in nuclear SSU rDNA of red and green algae: evidence of homing-endonuclease pseudogenes in the Bangiophyceae  

Microsoft Academic Search

The green alga Scenedesmus pupukensis and the red alga Porphyra spiralis contain large group-IC1 introns in their nuclear small subunit ribosomal RNA genes due to the presence of open reading frames\\u000a at the 5? end of the introns. The putative 555 amino-acid Scenedesmus-encoded protein harbors a sequence motif resembling the bacterial S9 ribosomal proteins. The Porphyra intron self-splices in?vitro, and

Peik Haugen; Volker A. R. Huss; Henrik Nielsen; Steinar Johansen

1999-01-01

338

Effect of substituted pyridazinone herbicides and of difunone (EMD-IT 5914) on carotenoid biosynthesis in green algae.  

PubMed

The carotenoid biosynthesis of the green alga Ankistrodesmus braunii is blocked if these cells are cultured in presence of sublethal doses of pyridazinone herbicides (San 9789, San 6706, BASF 44521) or of the herbicide difunone (EMD-IT 5914). The amount of colored carotenoids normally found in these algae is reduced drastically and the precursors phytoene and phytofluene are accumulated. Furthermore a decrease in the chlorophyll level occurs in the treated cells, but there is a stronger loss of chlorophyll a, resulting in a lowering of the chlorophyll a/b ratio with time. Concerning the activity of substituted pyridazinones leading to inhibition of carotenoid biosynthesis this effect can be related to the chemical structure of these compounds: a trifluormethyl substitution of the phenyl ring and a mono- or dimethyl substitution of the amine (San 9789, San 6706) or a methoxy group instead of the substituted amine (BASF 44521) are required both for this effect. Other pyridazinone derivatives with either a trifluoromethyl substitition of the phenyl ring (San 9774) or a dimethyl subsittution of the amine (San 9785) or a methoxy group (BASF 13761) are without any effect on the pigment pattern of these algae. PMID:138285

Urbach, D; Suchanka, M; Urbach, W

1976-01-01

339

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

SciTech Connect

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.

2011-05-13

340

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

341

Removal of bisphenol A by the freshwater green alga Monoraphidium braunii and the role of natural organic matter.  

PubMed

Phytoremediation of waters by aquatic organisms such as algae has been recently explored for the removal of organic pollutants possessing endocrine disrupting capacity. Monoraphidium braunii, a green alga known for rapid growth and good tolerance to different natural organic matter (NOM) qualities, was tested in this study for the ability to tolerate and remove the endocrine disruptor bisphenol A at concentrations of 2, 4 and 10mgL(-1), either in NOM-free or NOM-containing media. NOM at concentrations of 2, 5 and 20mgL(-1) of DOC, was added because it may interfere with xenobiotics and modify their effects, modulate algal growth performances or produce a trade-off of both effects. After 2 and 4 days of algal growth, the cell number and size, the maximum quantum yield of photosystem II in the dark or light adapted state, and the chlorophyll a content were recorded in order to evaluate the algal response to bisphenol A. Moreover, the residual bisphenol A was measured in the algal cultures by chromatographic technique. Results indicated that after 2 and 4 days bisphenol A at the lower concentrations was not toxic for alga, whereas at the highest concentration it reduced algal growth and photosynthetic efficiency. The sole NOM and its combinations with bisphenol A at the lower concentrations increased the cell number and the chlorophyll a content of algae. After 4-day growth, good removal efficiency was exerted by M. braunii at concentrations of 2, 4 and 10mgL(-1) removing, respectively, 39%, 48% and 35% of the initial bisphenol A. Lower removal percentages were found after 2-day growth in the different treatments. NOM at any concentration scarcely influenced the bisphenol A removal. On the basis of data obtained, the use of M. braunii could be reasonably recommended for the phytoremediation of aquatic environments from bisphenol A. PMID:22209372

Gattullo, C Eliana; Bährs, Hanno; Steinberg, Christian E W; Loffredo, Elisabetta

2012-02-01

342

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. PMID:19917118

2009-01-01

343

Metabolite profiling and integrative modeling reveal metabolic constraints for carbon partitioning under nitrogen starvation in the green algae Haematococcus pluvialis.  

PubMed

The green alga Hematococcus pluvialis accumulates large amounts of the antioxidant astaxanthin under inductive stress conditions, such as nitrogen starvation. The response to nitrogen starvation and high light leads to the accumulation of carbohydrates and fatty acids as well as increased activity of the tricarboxylic acid cycle. Although the behavior of individual pathways has been well investigated, little is known about the systemic effects of the stress response mechanism. Here we present time-resolved metabolite, enzyme activity, and physiological data that capture the metabolic response of H. pluvialis under nitrogen starvation and high light. The data were integrated into a putative genome-scale model of the green alga to in silico test hypotheses of underlying carbon partitioning. The model-based hypothesis testing reinforces the involvement of starch degradation to support fatty acid synthesis in the later stages of the stress response. In addition, our findings support a possible mechanism for the involvement of the increased activity of the tricarboxylic acid cycle in carbon repartitioning. Finally, the in vitro experiments and the in silico modeling presented here emphasize the predictive power of large scale integrative approaches to pinpoint metabolic adjustment to changing environments. PMID:25183014

Recht, Lee; Töpfer, Nadine; Batushansky, Albert; Sikron, Noga; Gibon, Yves; Fait, Aaron; Nikoloski, Zoran; Boussiba, Sammy; Zarka, Aliza

2014-10-31

344

Different fates of the chloroplast tufA gene following its transfer to the nucleus in green algae.  

PubMed Central

Previous work suggested that the tufA gene, encoding protein synthesis elongation factor Tu, was transferred from the chloroplast to the nucleus within the green algal lineage giving rise to land plants. In this report we investigate the timing and mode of transfer by examining chloroplast and nuclear DNA from the three major classes of green algae, with emphasis on the class Charophyceae, the proposed sister group to land plants. Filter hybridizations reveal a chloroplast tufA gene in all Ulvophyceae and Chlorophyceae and in some but not all Charophyceae. One charophycean alga, Coleochaete orbicularis, is shown to contain an intact but highly divergent chloroplast tufA gene, whose product is predicted to be non-functional in protein synthesis. We propose that a copy of the tufA gene was functionally transferred from the chloroplast to the nucleus early in the evolution of the Charophyceae, with chloroplast copies of varying function being retained in some but not all of the subsequently diverging lineages. This proposal is supported by the demonstration of multiple tufA-like sequences in Coleochaete nuclear DNA and in nuclear DNA from all other Charophyceae examined. Images PMID:2371274

Baldauf, S L; Manhart, J R; Palmer, J D

1990-01-01

345

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

346

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. PMID:24589311

2014-01-01

347

Bacterial diversity in surface water of the Yellow Sea during and after a green alga tide in 2008  

NASA Astrophysics Data System (ADS)

From May to August 2008, a large "green tide", consisting of the alga Ulva ( Enteromorpha) prolifera, occurred in the Yellow Sea, China, affecting the local marine ecosystem and human activities. We investigated the influence of the green tide on the microbial community in the surface seawater, at four sites from July to August 2008, using bacterial 16S rRNA gene clone libraries. We sequenced 228 clones of unique patterns identified by restriction fragment length polymorphism (RFLP) techniques. The results show that 228 sequenced clones fell into six bacterial phyla: Proteobacteria, Bacteroidetes, Cyanobacteria, Verrucomicrobia, Actinobacteria, and Planctomycetes. Alphaproteobacteria (33%), Gammaproteobacteria (25%), Bacteroidetes (23%) and Cyanobacteria (9%) dominated the assemblage. Comparison between samples collected in July (during the tide) and those collected in August (after the tide) showed that, in the microbial community, diversities of Alphaproteobacteria and Cyanobacteria increased after the tide, while those of Gammaproteobacteria and Bacteroidetes decreased. These results indicate that the green tide influenced the growth of some bacteria, and provide information for further studies on the interactions and relationships between U. prolifera and the bacterial community. This study suggests that microbial community analysis is a good approach to monitoring green tides.

Guo, Cong; Li, Fuchao; Jiang, Peng; Liu, Zhaopu; Qin, Song

2011-11-01

348

Spread of the introduced tropical green alga Caulerpa taxifolia in northern Mediterranean waters  

Microsoft Academic Search

The first report of Caulerpa taxifolia in the Mediterranean is from 1984. The alga was found on the rocky shore at Monaco, below the Oceanographic Museum, where\\u000a it had been on display in tropical aquaria. Within five years, there was an abundance of C. taxifolia on the shores around the first point of observation. In 1987, C. taxifolia appeared on

A. Meinesz; J. de Vaugelas; B. Hesse; X. Mari

1993-01-01

349

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

350

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

Microsoft Academic Search

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

Glenn W. Stratton

1987-01-01

351

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

352

Green Pacific Biologicals Rapid & stable nuclear genetic engineering of eukaryotic algae  

E-print Network

Convert more CO2 into oil Grow in open-ponds without contamination GPB's solutions [50-80% reduction · Algae-to-biofuels, big oil, Ag-biotech, High-margin products · Proprietary solutions for higher conversion of CO2 and oils secretion by non-toxic mechanism · 50%-80% reductions in costs · Licensing

353

Biosorption of Chromium(VI) From Aqueous solutions by green algae spirogyra species  

Microsoft Academic Search

Biosorption of heavy metals is an effective technology for the treatment of industrial wastewaters. Results are presented showing the sorption of Cr(VI) from solutions by biomass of filamentous algae Spirogyra species. Batch experiments were conducted to determine the adsorption properties of the biomass and it was observed that the adsorption capacity of the biomass strongly depends on equilibrium pH. Equilibrium

V. K. Gupta; A. K. Shrivastava; Neeraj Jain

2001-01-01

354

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

355

Induction of Metamorphosis of Larvae of the Green Sea Urchin, Strongylocentrotus droebachiensis, by Coralline Red Algae  

Microsoft Academic Search

The coralline red algae, Lithothumnion gla- ciale, Phymatolithon luevigat urn, P. rugulosum, and Cor- allinu ollicinulis, induced >85% of laboratory-reared lar- vae of Strongyloccntrotus droehachiensis to metamor- phose. Larvae must contact live L. glaciale or its spores for metamorphosis to occur: the inducer is not sensed in the water column. However, aqueous extracts of L. gfu- ciule can induce metamorphosis,

CHRISTOPHER M. PEARCE; ROBERT E. SCHEIBLING

1990-01-01

356

Transcriptomics of Desiccation Tolerance in the Streptophyte Green Alga Klebsormidium Reveal a Land Plant-Like Defense Reaction  

PubMed Central

Background Water loss has significant effects on physiological performance and survival rates of algae. However, despite the prominent presence of aeroterrestrial algae in terrestrial habitats, hardly anything is known about the molecular events that allow aeroterrestrial algae to survive harsh environmental conditions. We analyzed the transcriptome and physiology of a strain of the alpine aeroterrestrial alga Klebsormidium crenulatum under control and strong desiccation-stress conditions. Principal Findings For comparison we first established a reference transcriptome. The high-coverage reference transcriptome includes about 24,183 sequences (1.5 million reads, 636 million bases). The reference transcriptome encodes for all major pathways (energy, carbohydrates, lipids, amino acids, sugars), nearly all deduced pathways are complete or missing only a few transcripts. Upon strong desiccation, more than 7000 transcripts showed changes in their expression levels. Most of the highest up-regulated transcripts do not show similarity to known viridiplant proteins, suggesting the existence of some genus- or species-specific responses to desiccation. In addition, we observed the up-regulation of many transcripts involved in desiccation tolerance in plants (e.g. proteins similar to those that are abundant in late embryogenesis (LEA), or proteins involved in early response to desiccation ERD), and enzymes involved in the biosynthesis of the raffinose family of oligosaccharides (RFO) known to act as osmolytes). Major physiological shifts are the up-regulation of transcripts for photosynthesis, energy production, and reactive oxygen species (ROS) metabolism, which is supported by elevated cellular glutathione content as revealed by immunoelectron microscopy as well as an increase in total antiradical power. However, the effective quantum yield of Photosystem II and CO2 fixation decreased sharply under the applied desiccation stress. In contrast, transcripts for cell integrative functions such as cell division, DNA replication, cofactor biosynthesis, and amino acid biosynthesis were down-regulated. Significance This is the first study investigating the desiccation transcriptome of a streptophyte green alga. Our results indicate that the cellular response is similar to embryophytes, suggesting that embryophytes inherited a basic cellular desiccation tolerance from their streptophyte predecessors. PMID:25340847

Holzinger, Andreas; Kaplan, Franziska; Blaas, Kathrin; Zechmann, Bernd; Komsic-Buchmann, Karin; Becker, Burkhard

2014-01-01

357

Antitumor activity of marine algae  

Microsoft Academic Search

Powdered tissue from 46 species of air-dried marine algae (four green, 21 brown and 21 red algae) were screened for antitumor activity. Significant activity against Ehrlich carcinoma was found in the brown algae Scytosiphon lomentaria (69.8% inhibition), Lessonia nigrescens (60.0%), Laminaria japonica (57.6%), Sargassum ringgoldianum (46.5%), the red algae Porphyra yezoensis (53.2%) and Eucheuma gelatinae (52.1%) and the green alga

Hiroyuki Noda; Hideomi Amano; Koichi Arashima; Kazutosi Nisizawa

1990-01-01

358

Biogeography of Marine Algae  

E-print Network

Biogeography of Marine Algae David J Garbary, St Francis Xavier University, Antigonish, Nova Scotia and vicariance in establishing distributions and as factors associated with speciation. Since eukaryotic algae. There are many species that are virtually cosmopolitan (e.g. the green alga Enteromorpha intestinalis, the red

359

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

360

Anti-cancer effects of blue-green alga Spirulina platensis, a natural source of bilirubin-like tetrapyrrolic compounds.  

PubMed

Spirulina platensis is a blue-green alga used as a dietary supplement because of its hypocholesterolemic properties. Among other bioactive substances, it is also rich in tetrapyrrolic compounds closely related to bilirubin molecule, a potent antioxidant and anti-proliferative agent. The aim of our study was to evaluate possible anticancer effects of S. platensis and S. platensis-derived tetrapyrroles using an experimental model of pancreatic cancer. The anti-proliferative effects of S. platensis and its tetrapyrrolic components [phycocyanobilin (PCB) and chlorophyllin, a surrogate molecule for chlorophyll A] were tested on several human pancreatic cancer cell lines and xenotransplanted nude mice. The effects of experimental therapeutics on mitochondrial reactive oxygen species (ROS) production and glutathione redox status were also evaluated. Compared to untreated cells, experimental therapeutics significantly decreased proliferation of human pancreatic cancer cell lines in vitro in a dose-dependent manner (from 0.16 g•L-1 [S. platensis], 60 ?M [PCB], and 125 ?M [chlorophyllin], p<0.05). The anti-proliferative effects of S. platensis were also shown in vivo, where inhibition of pancreatic cancer growth was evidenced since the third day of treatment (p < 0.05). All tested compounds decreased generation of mitochondrial ROS and glutathione redox status (p = 0.0006; 0.016; and 0.006 for S. platensis, PCB, and chlorophyllin, respectively). In conclusion, S. platensis and its tetrapyrrolic components substantially decreased the proliferation of experimental pancreatic cancer. These data support a chemopreventive role of this edible alga. Furthermore, it seems that dietary supplementation with this alga might enhance systemic pool of tetrapyrroles, known to be higher in subjects with Gilbert syndrome. PMID:24552870

Koní?ková, Renata; Va?ková, Kate?ina; Vaníková, Jana; Vá?ová, Kate?ina; Muchová, Lucie; Subhanová, Iva; Zadinová, Marie; Zelenka, Jaroslav; Dvo?ák, Aleš; Kolá?, Michal; Strnad, Hynek; Rimpelová, Silvie; Ruml, Tomáš; J Wong, Ronald; Vítek, Libor

2014-01-01

361

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 60 min, uncoated form aggregated rapidly reaching aggregate sizes with hydrodynamic diameter of over 2500 nm within 60 min. Effective particle-particle interaction was reduced in the GA-coated NPs. Aggregates of about 440 nm hydrodynamic diameter were formed within 35 min. 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

362

Biomass production from the green algae Chlorella vulgaris and Ankistrodesmus braunii cultured heterotrophically  

Microsoft Academic Search

Ankistrodesmus braunii and Chlorella vulgaris were cultured heterotrophically under various operating conditions. The maximum rate of biomass production was 900 and 900 mg L-1 d-1 by C. vulgaris and 1000 and 700 mg L-1 d-1 by A. braunii in the light and dark, respectively. This indicates that these algae could produce in excess of 1530 dry weight tonnes ha-1 y-1

Robert E. Burrell; Colin I. Mayfield; William E. Inniss

1984-01-01

363

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

364

Preliminary laboratory experimentation on the potential of mass-scale cultivation of a high-potein blue-green alga, spirulina geitleri, utilizing cattle feedlot manure  

Microsoft Academic Search

Major detriments to beef production in Hawaii are the cost of feed and the problems associated with the treatment and disposal of the manure in a environmentally safe manner. In an effort to alleviate these problems, laboratory studies were conducted on the feasibility of culturing the high protein (> 50%) blue-green alga Spirulina in elutriated (washed) manure and in the

M. T. Santerre; G. L. Dugan; P. K. Takahashi

1978-01-01

365

Characterization of the heterotrimeric G-protein complex and its regulator from the green alga Chara braunii expands the evolutionary breadth of plant G-protein signaling.  

PubMed

The lack of heterotrimeric G-protein homologs in the sequenced genomes of green algae has led to the hypothesis that, in plants, this signaling mechanism coevolved with the embryophytic life cycle and the acquisition of terrestrial habitat. Given the large evolutionary gap that exists between the chlorophyte green algae and most basal land plants, the bryophytes, we evaluated the presence of this signaling complex in a charophyte green alga, Chara braunii, proposed to be the closest living relative of land plants. The C. braunii genome encodes for the entire G-protein complex, the G?, G?, and G? subunits, and the REGULATOR OF G-PROTEIN SIGNALING (RGS) protein. The biochemical properties of these proteins and their cross-species functionality show that they are functional homologs of canonical G-proteins. The subunit-specific interactions between CbG? and CbG?, CbG? and CbG?, and CbG? and CbRGS are also conserved, establishing the existence of functional G-protein complex-based signaling mechanisms in green algae. PMID:24179134

Hackenberg, Dieter; Sakayama, Hidetoshi; Nishiyama, Tomoaki; Pandey, Sona

2013-12-01

366

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

367

Draft Genome Sequence of Vibrio owensii GRA50-12, Isolated from Green Algae in the Intertidal Zone of Eastern Taiwan  

PubMed Central

Vibrio owensii GRA50-12 was isolated from symbiotic green algae of coral. The genome contains genes encoding toxin production, virulence regulation, stress response proteins, types II, IV, and VI secretion systems, and proteins for the metabolism of aromatic compounds, which reflects its pathogenic potential and its ecological roles in the ocean. PMID:25593265

Lin, Ling-Chun; Lin, Guang-Huey

2015-01-01

368

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

369

The complete chloroplast DNA sequences of the charophycean green algae Staurastrum and Zygnema reveal that the chloroplast genome underwent extensive changes during the evolution of the Zygnematales  

Microsoft Academic Search

BACKGROUND: The Streptophyta comprise all land plants and six monophyletic groups of charophycean green algae. Phylogenetic analyses of four genes from three cellular compartments support the following branching order for these algal lineages: Mesostigmatales, Chlorokybales, Klebsormidiales, Zygnematales, Coleochaetales and Charales, with the last lineage being sister to land plants. Comparative analyses of the Mesostigma viride (Mesostigmatales) and land plant chloroplast

Monique Turmel; Christian Otis; Claude Lemieux

2005-01-01

370

The complete chloroplast genome sequence of the chlorophycean green alga Scenedesmus obliquus reveals a compact gene organization and a biased distribution of genes on the two DNA strands  

Microsoft Academic Search

BACKGROUND: The phylum Chlorophyta contains the majority of the green algae and is divided into four classes. While the basal position of the Prasinophyceae is well established, the divergence order of the Ulvophyceae, Trebouxiophyceae and Chlorophyceae (UTC) remains uncertain. The five complete chloroplast DNA (cpDNA) sequences currently available for representatives of these classes display considerable variability in overall structure, gene

Jean-Charles de Cambiaire; Christian Otis; Claude Lemieux; Monique Turmel

2006-01-01

371

Draft Genome Sequence of Vibrio owensii GRA50-12, Isolated from Green Algae in the Intertidal Zone of Eastern Taiwan.  

PubMed

Vibrio owensii GRA50-12 was isolated from symbiotic green algae of coral. The genome contains genes encoding toxin production, virulence regulation, stress response proteins, types II, IV, and VI secretion systems, and proteins for the metabolism of aromatic compounds, which reflects its pathogenic potential and its ecological roles in the ocean. PMID:25593265

Lin, Ling-Chun; Lin, Guang-Huey; Tseng, Yi-Hsiung; Yu, Mei-Shiuan

2015-01-01

372

Effects of temperature on the astaxanthin productivity and light harvesting characteristics of the green alga Haematococcus pluvialis.  

PubMed

The green alga Haematococcus pluvialis, which accumulates astaxanthin at an optimal temperature of 20°C, was cultivated under temperatures of 20°C, 23.5°C, 27°C, and 30.5°C, in order to assess the effects on algal metabolism during the growth phase. The culture growth rate declined with above-optimal increases in temperature, and the final maximum cell concentration at 30.5°C reached only 35% of that attained at 20°C. On the contrary, the biomass productivity was increased under all the high-temperature conditions, probably reflecting the metabolism switch from cell duplication to energy accumulation that is typically observed in algal cultures subjected to environmental stress. Moreover, an increase in the light-harvesting capability of the alga was observed by means of the total pigment balance and the photosynthesis-intensity (PI) curve measured under the different cultivation conditions. Cultures kept at higher temperatures were able to better harvest and utilize the impinging light due to photo-acclimation. Finally, the differences in the astaxanthin metabolism were elucidated by subjecting the cultures to nitrogen starvation at 20°C and 27°C. In the culture at 27°C, a 1.4-fold increase in the astaxanthin productivity was observed when compared to that at 20°C, and the latter required almost two-fold more energy for the astaxanthin production compared with the 27°C culture. PMID:25441445

Giannelli, Luca; Yamada, Hiroyuki; Katsuda, Tomohisa; Yamaji, Hideki

2015-03-01

373

Selenium Accumulation in Unicellular Green Alga Chlorella vulgaris and Its Effects on Antioxidant Enzymes and Content of Photosynthetic Pigments  

PubMed Central

The aim of the present study was to investigate selenite effects in the unicellular green algae Chlorella vulgaris as a primary producer and the relationship with intracellular bioaccumulation. The effects of selenite were evaluated by measuring the effect of different selenite concentrations on algal growth during a 144 h exposure period. It was found that lower Se concentrations (?75 mg L?1) positively promoted C. vulgaris growth and acted as antioxidant by inhibiting lipid peroxidation (LPO) and intracellular reactive oxygen species (ROS). The antioxidative effect was associated with an increase in guaiacol peroxidase (GPX), catalase (CAT), superoxide dismutase (SOD) and photosynthetic pigments. Meanwhile, significant increase in the cell growth rate and organic Se content was also detected in the algae. In contrast, these changes were opposite in C. vulgaris exposed to Se higher than 100 mg L?1. The antioxidation and toxicity appeared to be correlated to Se bioaccumulation, which suggests the appropriate concentration of Se in the media accumulation of C. vulgaris should be 75 mg L?1. Taken together, C. vulgaris possesses tolerance to Se, and Se-Chlorella could be developed as antioxidative food for aquaculture and human health. PMID:25375113

Sun, Xian; Zhong, Yu; Huang, Zhi; Yang, Yufeng

2014-01-01

374

Hydrogen metabolism of green algae: discovery and early research - a tribute to Hans Gaffron and his coworkers.  

PubMed

The detection of hydrogen metabolism in green algae more than 60 years ago by Hans Gaffron dispelled the widely accepted dogma at that time that this feature was unique to prokaryotic organisms. Research on this unexpected aspect of algal physiology has continued until today because of its evolutionary implications and possible practical significance. This minireview focuses on the work of Gaffron and his collaborators, whose experiments provided most of the information about the mechanism of hydrogen metabolism in algae during the 35 years following its discovery. It is shown that the emergence of our present mechanistic concepts was closely linked to the changing perception of the process of photosynthetic water oxidation. Whereas the mechanism of 'photoreduction,' i.e., the photoassimilation of carbon dioxide with hydrogen as the electron donor, was well understood already by Gaffron's group as being a reaction mediated by Photosystem I only, a clear concept of the mechanism of light-dependent hydrogen production has been more difficult to establish. Gaffron and his collaborators provided ample evidence, however, that 'photohydrogen' evolution can be fueled by reducing equivalents derived from a photolysis of water as well as by an oxidation of internal and external organic molecules. The presently prevailing view embraces this concept of multiple pathways, but the relative contribution of each of them, and the regulatory mechanisms determining it, remain a matter of debate. PMID:16228569

Homann, Peter H

2003-01-01

375

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

376

A self-splicing group I intron in the nuclear pre-rRNA of the green alga, Ankistrodesmus stipitatus.  

PubMed

The nuclear small subunit ribosomal RNA gene of the unicellular green alga Ankistrodesmus stipitatus contains a group I intron, the first of its kind to be found in the nucleus of a member of the plant kingdom. The intron RNA closely resembles the group I intron found in the large subunit rRNA precursor of Tetrahymena thermophila, differing by only eight nucleotides of 48 in the catalytic core and having the same peripheral secondary structure elements. The Ankistrodesmus RNA self-splices in vitro, yielding the typical group I intron splicing intermediates and products. Unlike the Tetrahymena intron, however, splicing is accelerated by high concentrations of monovalent cations and is rate-limited by the exon ligation step. This system provides an opportunity to understand how limited changes in intron sequence and structure alter the properties of an RNA catalytic center. PMID:1886767

Dávila-Aponte, J A; Huss, V A; Sogin, M L; Cech, T R

1991-08-25

377

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

378

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. PMID:9596636

Amon, P; Haas, E; Sumper, M

1998-01-01

379

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

380

Elicitation of the most important structural properties of ionic liquids affecting ecotoxicity in limnic green algae; a QSAR approach.  

PubMed

Many ionic liquids are soluble in water and their impact on the aquatic environment has to be evaluated. However, due to the large number of ionic liquids and lack of experimental data, it is necessary to develop estimation procedures in order to reduce the materials and time consumption. In this study using multilayer perceptron neural network (MLP), ant colony optimization (ACO) and multiple linear regression (MLR) strategies, good predictive quantitative structure-activity relationships (QSAR) models were introduced and structural parameters affecting ecotoxicity of ionic liquids in limnic green algae (Scenedesmus vacuolatus) were revealed. Moreover, principal component analysis (PCA) and cluster analysis (CA) approaches were also applied to visualize any possible patterns or relationships among ionic liquids data. It was revealed that selected descriptors of the MLR model are also capable of clustering ionic liquids according to their four level of toxicity. PMID:23107477

Izadiyan, Parisa; Fatemi, M H; Izadiyan, Mahsa

2013-01-01

381

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

382

Negative Impact on Growth and Photosynthesis in the Green Alga Chlamydomonas reinhardtii in the Presence of the Estrogen 17?-Ethynylestradiol  

PubMed Central

It is well known that estrogenic compounds affect development of fertilized eggs of many species of birds, fish and amphibians through disrupted activity of carbonic anhydrase (CA). The most potent activity comes from the most commonly occurring synthetic sterol, 17?-Ethynylestradiol (EE2). Less is known about the responses of aquatic phytoplankton to these compounds. Here we show for the first time that, in comparision to the control, the addition of 7 µM EE2 reduced the growth rate of the green alga Chlamydomonas reinhardtii by 68% for cells grown at high CO2. When cells were grown in ambient air (low Ci) with a fully activated carbon concentrating mechanism through the induction of CA activity, the growth rates were reduced by as much as 119%. A reduced growth rate could be observed at EE2 concentrations as low as 10 pM. This was accompanied by a reduced maximum capacity for electron transport in photosystem II as determined by a lower FV/FM for low Ci-grown cells, which indicates the involvement of CAH3, a CA specifically located in the thylakoid lumen involved in proton pumping across the thylakoid membranes. These results were in agreement with an observed reduction in the chloroplastic affinity for Ci as shown by a strong increase in the Michaelis-Menten K0.5 for HCO3?. In itself, a lowering of the growth rate of a green alga by addition of the sterol EE2 warrants further investigation into the potential environmental impact by the release of treated waste water. PMID:25310092

Pocock, Tessa; Falk, Stefan

2014-01-01

383

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

384

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. 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.

2014-01-01

385

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

386

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 Algae1[W][OA  

PubMed Central

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 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 CO2 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.

2008-01-01

387

An update on carotenoid biosynthesis in algae: phylogenetic evidence for the existence of two classes of phytoene synthase.  

PubMed

Carotenoids play crucial roles in structure and function of the photosynthetic apparatus of bacteria, algae, and higher plants. The entry-step reaction to carotenoid biosynthesis is catalyzed by the phytoene synthase (PSY), which is structurally and functionally related in all organisms. A comparative genomic analysis regarding the PSY revealed that the green algae Ostreococcus and Micromonas possess two orthologous copies of the PSY genes, indicating an ancient gene duplication event that produced two classes of PSY in algae. However, some other green algae (Chlamydomonas reinhardtii, Chlorella vulgaris, and Volvox carteri), red algae (Cyanidioschyzon merolae), diatoms (Thalassiosira pseudonana and Phaeodactylum tricornutum), and higher plants retained only one class of the PSY gene whereas the other gene copy was lost in these species. Further, similar to the situation in higher plants recent gene duplications of PSY have occurred for example in the green alga Dunaliella salina/bardawil. As members of the PSY gene families in some higher plants are differentially regulated during development or stress, the discovery of two classes of PSY gene families in some algae suggests that carotenoid biosynthesis in these algae is differentially regulated in response to development and environmental stress as well. PMID:19066941

Tran, Duc; Haven, James; Qiu, Wei-Gang; Polle, Juergen E W

2009-02-01

388

Updated Cost Analysis of Photobiological Hydrogen Production from Chlamydomonas reinhardtii Green Algae: Milestone Completion Report  

SciTech Connect

This report updates the 1999 economic analysis of NREL's photobiological hydrogen production from Chlamydomonas reinhardtii. The previous study had looked mainly at incident light intensities, batch cycles and light adsorption without directly attempting to model the saturation effects seen in algal cultures. This study takes a more detailed look at the effects that cell density, light adsorption and light saturation have on algal hydrogen production. Performance estimates based on actual solar data are also included in this study. Based on this analysis, the estimated future selling price of hydrogen produced from algae ranges $0.57/kg to $13.53/kg.

Amos, W. A.

2004-01-01

389

The Glass Menagerie: diatoms for novel applications in nanotechnology.  

PubMed

Diatoms are unicellular, eukaryotic, photosynthetic algae that are found in aquatic environments. Diatoms have enormous ecological importance on this planet and display a diversity of patterns and structures at the nano- to millimetre scale. Diatom nanotechnology, a new interdisciplinary area, has spawned collaborations in biology, biochemistry, biotechnology, physics, chemistry, material science and engineering. We survey diatom nanotechnology since 2005, emphasizing recent advances in diatom biomineralization, biophotonics, photoluminescence, microfluidics, compustat domestication, multiscale porosity, silica sequestering of proteins, detection of trace gases, controlled drug delivery and computer design. Diatoms might become the first organisms for which the gap in our knowledge of the relationship between genotype and phenotype is closed. PMID:19167770

Gordon, Richard; Losic, Dusan; Tiffany, Mary Ann; Nagy, Stephen S; Sterrenburg, Frithjof A S

2009-02-01

390

Toxicity of pH, heavy metals and bisulfite to a freshwater green alga  

SciTech Connect

Low pH markedly reduced the growth and photosynthetic activity of an Ankistrodesmus sp. The alga could not grow at pH 3 and only slight growth occurred at pH 4. The alga grew well above pH 4 with maximum growth occurring at pH 6. The fixation of /sup 14/CO/sub 2/ followed a similar pattern with pH. The algal cells were also sensitive to mercury and bisulfite in acidic conditions. Algal growth and photosynthesis were reduced by mercury and bisulfite more at pH 5 but not at pH 7. Lead was relatively non-toxic to the algal cells at both pH levels. Bisulfite inhibited the membrane transport of ..cap alpha..-amino-/sup 14/ C-isobutyric acid at pH 5 but not at pH7. The results suggest that algal growth and activity may be reduced in acidic lakes by low pH and that the toxicity of mercury and bisulfite is enhanced in acidic conditions.

Baker, M.D. (Univ. of Waterloo, Ontario); Mayfield, C.I.; Inniss, W.E.; Wong, P.T.S.

1983-01-01

391

Inhibitory effects of silver nanoparticles in two green algae, Chlorella vulgaris and Dunaliella tertiolecta.  

PubMed

Freshwater microalga Chlorella vulgaris and marine microalga Dunaliella tertiolecta were used to investigate toxic effects induced by 50 nm silver nanoparticles (AgNPs). To induce AgNPs effect, we exposed Chlorella vulgaris and Dunaliella tertiolecta for 24h to 0-10 mg/L. We showed that growth media had different effects in AgNPs agglomerates' formation. Cellular viability, reactive oxygen species (ROS) formation and lipids peroxidation were employed to assess the toxic effects of AgNPs. AgNPs were able to interact directly with the Chlorella vulgaris cells surface and large aggregates were observed. AgNPs have a negative effect on Chlorella vulgaris and Dunaliella tertiolecta, as manifested by a strong decrease in chlorophyll content, viable algal cells, increased ROS formation and lipids peroxidation. The variability in sensitivity of both algae towards AgNPs was observed. We conclude that AgNPs have a negative effect on aquatic algae and these alterations might have serious consequences on structure and function of aquatic plant communities. PMID:22138148

Oukarroum, Abdallah; Bras, Sébastien; Perreault, François; Popovic, Radovan

2012-04-01

392

Nuclear DNA Content Estimates in Multicellular Green, Red and Brown Algae: Phylogenetic Considerations  

PubMed Central

• Background and Aims Multicellular eukaryotic algae are phylogenetically disparate. Nuclear DNA content estimates have been published for fewer than 1 % of the described species of Chlorophyta, Phaeophyta and Rhodophyta. The present investigation aims to summarize the state of our knowledge and to add substantially to our database of C-values for theses algae. • Methods The DNA-localizing fluorochrome DAPI (4?, 6-diamidino-2-phenylindole) and RBC (chicken erythrocyte) standard were used to estimate 2C values with static microspectrophotometry. • Key Results 2C DNA contents for 85 species of Chlorophyta range from 0·2–6·1 pg, excluding the highly polyploidy Charales and Desmidiales with DNA contents of up to 39·2 and 20·7 pg, respectively. 2C DNA contents for 111 species of Rhodophyta range from 0·1–2·8 pg, and for 44 species of Phaeophyta range from 0·2–1·8 pg. • Conclusions New availability of consensus higher-level molecular phylogenies provides a framework for viewing C-value data in a phylogenetic context. Both DNA content ranges and mean values are greater in taxa considered to be basal. It is proposed that the basal, ancestral genome in each algal group was quite small. Both mechanistic and ecological processes are discussed that could have produced the observed C-value ranges. PMID:15596456

KAPRAUN, DONALD F.

2005-01-01

393

Noninvasive measurement of membrane potential modulation in microorganisms: photosynthesis in green algae.  

PubMed

Cell membrane potential (CMP) modulation is a physical measurement to quantitatively probe cell physiology in real time at high specificity. Electrochemical field effect transistors (eFETs) made from graphene and Si nanowire provide strong mechanical and electrical coupling with neurons and muscle cells to noninvasively measure CMP at high sensitivity. To date, there are no noninvasive methods to study electrophysiology of microorganisms because of stiff cell walls and significantly smaller membrane polarizations. An eFET made from the smallest possible nanostructure, a nanoparticle, with sensitivity to a single-electron charge is developed to noninvasively measure CMP modulation in algae. The applicability of the device is demonstrated by measuring CMP modulation due to a light-induced proton gradient inside the chloroplast during photosynthesis. The ?9 mV modulation in CMP in algae is consistent with the absorbance spectrum of chlorophyll, photosynthetic pathway, and inorganic carbon source concentration in the environment. The method can potentially become a routine method to noninvasively study electrophysiology of cells, such as microorganisms for biofuels. PMID:24354302

Lee, Eun-Hee; Lee, Seung-Woo; Saraf, Ravi F

2014-01-28

394

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.

395

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

396

Hydrogen production from salt water by Marine blue green algae and solar radiation  

NASA Technical Reports Server (NTRS)

Two marine bluegreen algae, Oscillatoria sp. Miami BG 7 and Synechococcus sp Miami 041511 have been selected as the result of over 10 years continuous and intensive effort of isolation, growth examination, and the screening of hydrogen photoproduction capability in this laboratory. Both strains photoproduced hydrogen for several days at high rates and a quantity of hydrogen was accumulated in a closed vessel. Overall hydrogen donor substance of the hydrogen photoproduction was found to be salt water. Using strain Miami BG 7, a two step method of hydrogen photoproduction from salt water was successfully developed and this was recycled several times over a one month period using both free cells and immobilized cells in both indoor and outdoor under natural sunlight. According to these experiments, a prototype floating hydrogen production system was designed for further development of the biosolar hydrogen production system.

Mitsui, A.; Rosner, D.; Kumazawa, S.; Barciela, S.; Phlips, E.

1985-01-01

397

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

398

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

NASA Technical Reports Server (NTRS)

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 was 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 percent) at a rate of 100 to approx. 150 ml per minute could be obtained.

Oguchi, Mitsuo; Otsubo, Koji; Nitta, Keiji; Hatayama, Shigeki

1987-01-01

399

The flagellar apparatus structure in Microspora ( Chlorophyceae ) confirms a close evolutionary relationship with unicellular green algae  

Microsoft Academic Search

The spatial configuration of the flagellar apparatus of the biflagellate zoospores of the green algal genusMicrospora is reconstructed by serial sectioning analysis using transmission electron microscopy. Along with the unequal length of the flagella, the most remarkable characteristics of the flagellar apparatus are: (1) the subapical emergence of the flagella (especially apparent with scanning electron microscopy); (2) the parallel orientation

Gijsbert M. Lokhorst; Wim Star

1999-01-01

400

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

401

Action Spectrum for Developmental Photo-Induction of the Blue-Green Alga Nostoc muscorum.  

PubMed

The dark-grown cyanophyte requires a brief exposure to light from the 650 mmicro region of the spectrum before it can complete its developmental cycle. Induction is reversed by exposure to green light. A blue protein, presumably allophycocyanin (absorption maximum, 650 mmicro) has been demonstrated in aqueous extracts of the cyanophycean cells. PMID:17836542

Lazaroff, N; Schiff, J

1962-08-24

402

Action Spectrum for Developmental PhotoInduction of the Blue-Green Alga Nostoc muscorum  

Microsoft Academic Search

The dark-grown cyanophyte requires a brief exposure to light from the 650 mmu region of the spectrum before it can complete its developmental cycle. Induction is reversed by exposure to green light. A blue protein, presumably allophycocyanin (absorption maximum, 650 mmu ) has been demonstrated in aqueous extracts of the cyanophycean cells.

Norman Lazaroff; Jerome Schiff

1962-01-01

403

Molecular and biochemical analysis of the first ARA6 homologue, a RAB5 GTPase, from green algae.  

PubMed

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 25.4 kDa, 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. PMID:24127512

Hoepflinger, Marion C; Geretschlaeger, Anja; Sommer, Aniela; Hoeftberger, Margit; Nishiyama, Tomoaki; Sakayama, Hidetoshi; Hammerl, Peter; Tenhaken, Raimund; Ueda, Takashi; Foissner, Ilse

2013-12-01

404

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. PMID:24127512

Foissner, Ilse

2013-01-01

405

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

406

The concept of "Green" has always been understood as expensive and not competitive. The new technologies that allow the efficient use of carbon atoms from inexpensive biomasses, even before the utilization of algae,  

E-print Network

the utilization of algae, have provided the opportunity to be "green and competitive" for the first timeThe concept of "Green" has always been understood as expensive and not competitive. The new in the world. Green Chemistry and Entrepreneurship: the Opportunities Guido Ghisolfi ETH Hönggerberg, HCI G 3

Sandoghdar, Vahid

407

Evolutionary Origins and Functions of the Carotenoid Biosynthetic Pathway in Marine Diatoms  

PubMed Central

Carotenoids are produced by all photosynthetic organisms, where they play essential roles in light harvesting and photoprotection. The carotenoid biosynthetic pathway of diatoms is largely unstudied, but is of particular interest because these organisms have a very different evolutionary history with respect to the Plantae and are thought to be derived from an ancient secondary endosymbiosis between heterotrophic and autotrophic eukaryotes. Furthermore, diatoms have an additional xanthophyll-based cycle for dissipating excess light energy with respect to green algae and higher plants. To explore the origins and functions of the carotenoid pathway in diatoms we searched for genes encoding pathway components in the recently completed genome sequences of two marine diatoms. Consistent with the supplemental xanthophyll cycle in diatoms, we found more copies of the genes encoding violaxanthin de-epoxidase (VDE) and zeaxanthin epoxidase (ZEP) enzymes compared with other photosynthetic eukaryotes. However, the similarity of these enzymes with those of higher plants indicates that they had very probably diversified before the secondary endosymbiosis had occurred, implying that VDE and ZEP represent early eukaryotic innovations in the Plantae. Consequently, the diatom chromist lineage likely obtained all paralogues of ZEP and VDE genes during the process of secondary endosymbiosis by gene transfer from the nucleus of the algal endosymbiont to the host nucleus. Furthermore, the presence of a ZEP gene in Tetrahymena thermophila provides the first evidence for a secondary plastid gene encoded in a heterotrophic ciliate, providing support for the chromalveolate hypothesis. Protein domain structures and expression analyses in the pennate diatom Phaeodactylum tricornutum indicate diverse roles for the different ZEP and VDE isoforms and demonstrate that they are differentially regulated by light. These studies therefore reveal the ancient origins of several components of the carotenoid biosynthesis pathway in photosynthetic eukaryotes and provide information about how they have diversified and acquired new functions in the diatoms. PMID:18682837

Coesel, Sacha; Oborník, Miroslav; Varela, Joao; Falciatore, Angela; Bowler, Chris

2008-01-01

408

Author's personal copy A time-calibrated multi-gene phylogeny of the diatom genus Pinnularia  

E-print Network

., 1990) and a diplontic life cycle involving gradual size reduc- tion during vegetative divisions. Introduction Diatoms are an extremely diverse group of unicellular algae that are uniquely characterized

Wolfe, Alexander P.

409

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. PMID:17222354

Lemieux, Claude; Otis, Christian; Turmel, Monique

2007-01-01

410

Enteromorpha compressa (L.) Greville an edible green alga as a source of antiallergic principle (S)  

Microsoft Academic Search

Enteromorpha compressa a marine green algal species grows extensively in North coastal Andhra Pradesh. Besides its nutritional importance it has\\u000a also been identified as source of anti-anaphylactic compound(s).E. compressa extracts alleviated the IgE levels raised against ovalbumin and other allergens in mice. Further,Enteromorpha extract also significantly down regulated the serum IgE levels in different murine models irrespective of their genetic

B. Venkata Raman; D. N. Rao; T. M. Radhakrishnan

2004-01-01

411

The chloroplast genome of the diatom Seminavis robusta: new features introduced through multiple mechanisms of horizontal gene transfer.  

PubMed

The chloroplasts of heterokont algae such as diatoms are the result of a secondary endosymbiosis event, in which a red alga was engulfed by a non-photosynthetic eukaryote. The diatom chloroplast genomes sequenced to date show a high degree of similarity, but some examples of gene replacement or introduction of genes through horizontal gene transfer are known. The evolutionary origin of the gene transfers is unclear. We have sequenced and characterised the complete chloroplast genome and a putatively chloroplast-associated plasmid of the pennate diatom Seminavis robusta. The chloroplast genome contains two introns, a feature that has not previously been found in diatoms. The group II intron of atpB appears to be recently transferred from a Volvox-like green alga. The S. robusta chloroplast genome (150,905 bp) is the largest diatom chloroplast genome characterised to date, mainly due to the presence of four large gene-poor regions. Open reading frames (ORFs) encoded by the gene-poor regions show similarity to putative proteins encoded by the chloroplast genomes of different heterokonts, as well as the plasmids pCf1 and pCf2 found in the diatom Cylindrotheca fusiformis. A tyrosine recombinase and a serine recombinase are encoded by the S. robusta chloroplast genome, indicating a possible mechanism for the introduction of novel genes. A plasmid with similarity to pCf2 was also identified. Phylogenetic analyses of three ORFs identified on pCf2 suggest that two of them are part of an operon-like gene cluster conserved in bacteria. Several genetic elements have moved through horizontal gene transfer between the chloroplast genomes of different heterokonts. Two recombinases are likely to promote such gene insertion events, and the plasmid identified may act as vectors in this process. The copy number of the plasmid was similar to that of the plastid genome indicating a plastid localization. PMID:24365712

Brembu, Tore; Winge, Per; Tooming-Klunderud, Ave; Nederbragt, Alexander J; Jakobsen, Kjetill S; Bones, Atle M

2014-08-01

412

The liverwort Pellia endiviifolia shares microtranscriptomic traits that are common to green algae and land plants.  

PubMed

Liverworts are the most basal group of extant land plants. Nonetheless, the molecular biology of liverworts is poorly understood. Gene expression has been studied in only one species, Marchantia polymorpha. In particular, no microRNA (miRNA) sequences from liverworts have been reported. Here, Illumina-based next-generation sequencing was employed to identify small RNAs, and analyze the transcriptome and the degradome of Pellia endiviifolia. Three hundred and eleven conserved miRNA plant families were identified, and 42 new liverwort-specific miRNAs were discovered. The RNA degradome analysis revealed that target mRNAs of only three miRNAs (miR160, miR166, and miR408) have been conserved between liverworts and other land plants. New targets were identified for the remaining conserved miRNAs. Moreover, the analysis of the degradome permitted the identification of targets for 13 novel liverwort-specific miRNAs. Interestingly, three of the liverwort microRNAs show high similarity to previously reported miRNAs from Chlamydomonas reinhardtii. This is the first observation of miRNAs that exist both in a representative alga and in the liverwort P. endiviifolia but are not present in land plants. The results of the analysis of the P. endivifolia microtranscriptome support the conclusions of previous studies that placed liverworts at the root of the land plant evolutionary tree of life. PMID:25530158

Alaba, Sylwia; Piszczalka, Pawel; Pietrykowska, Halina; Pacak, Andrzej M; Sierocka, Izabela; Nuc, Przemyslaw W; Singh, Kashmir; Plewka, Patrycja; Sulkowska, Aleksandra; Jarmolowski, Artur; Karlowski, Wojciech M; Szweykowska-Kulinska, Zofia

2015-04-01

413

The liverwort Pellia endiviifolia shares microtranscriptomic traits that are common to green algae and land plants  

PubMed Central

Liverworts are the most basal group of extant land plants. Nonetheless, the molecular biology of liverworts is poorly understood. Gene expression has been studied in only one species, Marchantia polymorpha. In particular, no microRNA (miRNA) sequences from liverworts have been reported. Here, Illumina-based next-generation sequencing was employed to identify small RNAs, and analyze the transcriptome and the degradome of Pellia endiviifolia. Three hundred and eleven conserved miRNA plant families were identified, and 42 new liverwort-specific miRNAs were discovered. The RNA degradome analysis revealed that target mRNAs of only three miRNAs (miR160, miR166, and miR408) have been conserved between liverworts and other land plants. New targets were identified for the remaining conserved miRNAs. Moreover, the analysis of the degradome permitted the identification of targets for 13 novel liverwort-specific miRNAs. Interestingly, three of the liverwort microRNAs show high similarity to previously reported miRNAs from Chlamydomonas reinhardtii. This is the first observation of miRNAs that exist both in a representative alga and in the liverwort P. endiviifolia but are not present in land plants. The results of the analysis of the P. endivifolia microtranscriptome support the conclusions of previous studies that placed liverworts at the root of the land plant evolutionary tree of life. PMID:25530158

Alaba, Sylwia; Piszczalka, Pawel; Pietrykowska, Halina; Pacak, Andrzej M; Sierocka, Izabela; Nuc, Przemyslaw W; Singh, Kashmir; Plewka, Patrycja; Sulkowska, Aleksandra; Jarmolowski, Artur; Karlowski, Wojciech M; Szweykowska-Kulinska, Zofia

2015-01-01

414

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. PMID:20390105

Güven, Kas?m Cemal; Percot, Aline; Sezik, Ekrem

2010-01-01

415

Alkaloids in marine algae  

E-print Network

Abstract: 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.

Kas?m Cemal Güven; Aline Percot; Ekrem Sezik

416

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

417

Inhibition of tumor invasion and metastasis by calciumspirulan (Ca-SP), a novel sulfated polysaccharide derived from a blue-green alga, Spirulina platensis  

Microsoft Academic Search

We have investigated the effect of calcium spirulan (Ca-SP) isolated from a blue-green alga, Spirulinaplatensis, which is a sulfated polysaccharide chelating calcium and mainly composed of rhamnose, on inva-sionof B16-BL6 melanoma, Colon 26 M3.1 carcinoma and HT-1080 fibrosarcoma cells through reconsti-tutedbasement membrane (Matrigel). Ca-SP significantly inhibited the invasion of these tumor cells throughMatrigel\\/fibronectin-coated filters. Ca-SP also inhibited the haptotactic migration

Takaaki Mishima; Jun Murata; Minako Toyoshima; Hideki Fujii; Motowo Nakajima; Toshimitsu Hayashi; Toshimitsu Kato; Ikuo Saiki

1998-01-01

418

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

419

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

420

The intron of a plastid gene from a green alga contains an open reading frame for a reverse transcriptase-like enzyme  

Microsoft Academic Search

Plastid (pt) and mitochondrial (mt) DNA were isolated from the unicellular green alga KS3\\/2, which is presumed to be a species of the genera Ankistrodesmus or Monoraphidium. The DNA species are characterized by their different densities (pt, 1.685 g\\/ml; mt, 1.695 g\\/ml), individual restriction patterns, and their respective sizes of 130 and 47 kb. Using an intronic sequence from fungal

Ulrich Kiick

1989-01-01

421

Close association of centrosomes to the distal ends of the microbody during its growth, division and partitioning in the green alga Klebsormidium flaccidum  

Microsoft Academic Search

Summary.  Division and partitioning of microbodies (peroxisomes) of the green alga Klebsormidium flaccidum, whose cells contain a single microbody, were investigated by electron microscopy. In interphase, the rod-shaped microbody\\u000a is present between the nucleus and the single chloroplast, oriented perpendicular to the pole-to-pole direction of the future\\u000a spindle. A centriole pair associates with one distal end of the microbody. In prophase,

Minoru Honda; Haruki Hashimoto

2007-01-01

422

Effects of snail grazing and nutrient release on growth of the macrophytes Ceratophyllum demersum and Elodea canadensis and the filamentous green alga Cladophora sp  

Microsoft Academic Search

The effects of snail (Lymnaea (Galba) turricula) nutrient release and grazing on young macrophytes and filamentous green algae were examined in a laboratory experiment. Snails released an average of 24.2 µg PO4-P and 48.9 µg NH4-N g-1 snail FW d-1. Snails consumed Cladophora sp. at the highest rate (45 mg g-1 snail FW d-1), Elodea canadensis at a lower rate

Agnieszka Pinowska

2002-01-01

423

Dynamics of the microtubular cytoskeleton in the green alga Aphanochaete magna (Chlorophyta) . I. Late mitotic stages and the origin and development of the phycoplast  

Microsoft Academic Search

Summary The spatial and temporal organization of the microtubular cytoskeleton at the transitional stage of mitosis and cytokinesis has been studied in the chaetophoralean green algaAphanochaete magna using indirect immunofluorescence light microscopy and transmission electron microscopic analysis of serial sections including computer-aided three-dimensional reconstruction. At late mitosis, elaborate asterlike microtubule systems including bundles interconnecting both centriolar regions are present. These

P. J. Segaar; G. M. Lokhorst

1988-01-01

424

Marine green algae Codium iyengarii as a good bio-sorbent for elimination of reactive black 5 from aqueous solution.  

PubMed

The green seaweeds Codium iyengarii (C. iyengarii) was used to prepare as an adsorbent surface for the deletion of Reactive Black 5 (RB 5) from aqueous solution via adsorption. The batch technique was adopted under the optimal condition of amount of adsorbent, agitation time, concentration of dye, and at neutral and low pH. The depletion in concentration of the dye was monitored by Schimadzo 180 AUV/Visible spectrophotometer. It was initially monolayer adsorption, which showed multilayered formation later on with the passage of time at low and neutral pH. The Results displayed that adsorptive ability of C. iyengarii was 1.95-3.82mg/g with an elevation in primary application of dye contents (50ppm-70 ppm). The elimination data were well stable into the Langmuir and Freundlich adsorption isotherm equations. The Langmuir (R2=0.9848) and Freundlich (R2=0.9441) constants for biosorption of RB 5 on green algae were determined. The coefficient relation values suggested that the Langmuir isotherm was well fitted. It explained the interaction of surface molecules, which helps in well organization of dye molecules in a monolayer formation initially on algal biomass. The pseudo first and second order rate equations were applied to link the investigational statistics and found that the second order rate expression was found to be more suitable for both the models. The absorption spectrum of RB 5 before and after adsorption with respect to time was monitored which clearly indicate that C. iyengarii was much effective surface at very low quantity. PMID:25176238

Azmat, Rafia

2014-09-01

425

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

426

Quality evaluation of the edible blue-green alga Nostoc flagelliforme using a chlorophyll fluorescence parameter and several biochemical markers.  

PubMed

Nostoc flagelliforme is an edible blue-green alga with herbal and dietary values. Due to the diminishing supply of natural N. flagelliforme and the large investment on the development of its cultivation technology, it is anticipated that artificially cultured N. flagelliforme will soon sustain the market supply. Once this change occurs, the storage-associated quality problem will become the focus of attention for future trade. In this paper, we used a chlorophyll fluorescence parameter, maximum quantum efficiency of Photosystem II (Fv/Fm), and several biomarkers to evaluate the quality of several N. flagelliforme samples. It was found that longer storage times resulted in darker coloured solutions (released pigments) and decreased amounts of chlorophyll a (Chl a) and water-soluble sugars (WSS). Additionally, a higher Fv/Fm value suggests better physiological recovery and quality. In actual application, determination of Fv/Fm would be the first step for evaluating the quality of N. flagelliforme, and the biochemical indexes would serve as good secondary markers. PMID:24054244

Gao, Xiang; Yang, Yiwen; Ai, Yufeng; Luo, Hongyi; Qiu, Baosheng

2014-01-15

427

Biosorption of Pb(II) and Cd(II) from aqueous solution using green alga (Ulva lactuca) biomass.  

PubMed

The biosorption characteristics of Pb(II) and Cd(II) ions from aqueous solution using the green alga (Ulva lactuca) biomass were investigated as a function of pH, biomass dosage, contact time, and temperature. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) models were applied to describe the biosorption isotherm of the metal ions by U. lactuca biomass. Langmuir model fitted the equilibrium data better than the Freundlich isotherm. The monolayer biosorption capacity of U. lactuca biomass for Pb(II) and Cd(II) ions was found to be 34.7mg/g and 29.2mg/g, respectively. From the D-R isotherm model, the mean free energy was calculated as 10.4kJ/mol for Pb(II) biosorption and 9.6kJ/mol for Cd(II) biosorption, indicating that the biosorption of both metal ions was taken place by chemisorption. The calculated thermodynamic parameters (DeltaG degrees , DeltaH degrees and DeltaS degrees ) showed that the biosorption of Pb(II) and Cd(II) ions onto U. lactuca biomass was feasible, spontaneous and exothermic under examined conditions. Experimental data were also tested in terms of biosorption kinetics using pseudo-first-order and pseudo-second-order kinetic models. The results showed that the biosorption processes of both metal ions followed well pseudo-second-order kinetics. PMID:17689186

Sari, Ahmet; Tuzen, Mustafa

2008-03-21

428

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

429

3-D analysis of dictyosomes and multivesicular bodies in the green alga Micrasterias denticulata by FIB/SEM tomography?  

PubMed Central

In the present study we employ FIB/SEM tomography for analyzing 3-D architecture of dictyosomes and formation of multivesicular bodies (MVB) in high pressure frozen and cryo-substituted interphase cells of the green algal model system Micrasterias denticulata. The ability of FIB/SEM of milling very thin ‘slices’ (5–10 nm), viewing the block face and of capturing cytoplasmic volumes of several hundred ?m3 provides new insight into the close spatial connection of the ER–Golgi machinery in an algal cell particularly in z-direction, complementary to informations obtained by TEM serial sectioning or electron tomography. Our FIB/SEM series and 3-D reconstructions show that interphase dictyosomes of Micrasterias are not only closely associated to an ER system at their cis-side which is common in various plant cells, but are surrounded by a huge “trans-ER” sheath leading to an almost complete enwrapping of dictyosomes by the ER. This is particularly interesting as the presence of a trans-dictyosomal ER system is well known from mammalian secretory cells but not from cells of higher plants to which the alga Micrasterias is closely related. In contrast to findings in plant storage tissue indicating that MVBs originate from the trans-Golgi network or its derivatives our investigations show that MVBs in Micrasterias are in direct spatial contact with both, trans-Golgi cisternae and the trans-ER sheath which provides evidence that both endomembrane compartments are involved in their formation. PMID:24135121

Wanner, Gerhard; Schäfer, Tillman; Lütz-Meindl, Ursula

2013-01-01

430

A freshwater green alga under cadmium stress: ameliorating calcium effects on ultrastructure and photosynthesis in the unicellular model Micrasterias.  

PubMed

Cadmium is a highly toxic heavy metal pollutant arising mainly from increasing industrial disposal of electronic components. Due to its high solubility it easily enters soil and aquatic environments. Via its similarity to calcium it may interfere with different kinds of Ca dependent metabolic or developmental processes in biological systems. In the present study we investigate primary cell physiological, morphological and ultrastructural responses of Cd on the unicellular freshwater green alga Micrasterias which has served as a cell biological model system since many years and has proved to be highly sensitive to any kind of abiotic stress. Our results provide evidence that the severe Cd effects in Micrasterias such as unidirectional disintegration of dictyosomes, occurrence of autophagy, decline in photosystem II activity and oxygen production as well as marked structural damage of the chloroplast are based on a disturbance of Ca homeostasis probably by displacement of Ca by Cd. This is indicated by the fact that physiological and structural cadmium effects could be prevented in Micrasterias by pre-treatment with Ca. Additionally, thapsigargin an inhibitor of animal and plant Ca(2+)-ATPase mimicked the adverse Cd induced morphological and functional effects on dictyosomes. Recovery experiments indicated rapid repair mechanisms after Cd stress. PMID:22762790

Andosch, Ancuela; Affenzeller, Matthias J; Lütz, Cornelius; Lütz-Meindl, Ursula

2012-10-15

431

3-D analysis of dictyosomes and multivesicular bodies in the green alga Micrasterias denticulata by FIB/SEM tomography.  

PubMed

In the present study we employ FIB/SEM tomography for analyzing 3-D architecture of dictyosomes and formation of multivesicular bodies (MVB) in high pressure frozen and cryo-substituted interphase cells of the green algal model system Micrasterias denticulata. The ability of FIB/SEM of milling very thin 'slices' (5-10 nm), viewing the block face and of capturing cytoplasmic volumes of several hundred ?m(3) provides new insight into the close spatial connection of the ER-Golgi machinery in an algal cell particularly in z-direction, complementary to informations obtained by TEM serial sectioning or electron tomography. Our FIB/SEM series and 3-D reconstructions show that interphase dictyosomes of Micrasterias are not only closely associated to an ER system at their cis-side which is common in various plant cells, but are surrounded by a huge "trans-ER" sheath leading to an almost complete enwrapping of dictyosomes by the ER. This is particularly interesting as the presence of a trans-dictyosomal ER system is well known from mammalian secretory cells but not from cells of higher plants to which the alga Micrasterias is closely related. In contrast to findings in plant storage tissue indicating that MVBs originate from the trans-Golgi network or its derivatives our investigations show that MVBs in Micrasterias are in direct spatial contact with both, trans-Golgi cisternae and the trans-ER sheath which provides evidence that both endomembrane compartments are involved in their formation. PMID:24135121

Wanner, Gerhard; Schäfer, Tillman; Lütz-Meindl, Ursula

2013-11-01

432

Chlorophyll triplet states associated with Photosystem I and Photosystem II in thylakoids of the green alga Chlamydomonas reinhardtii.  

PubMed

The analysis of FDMR spectra, recorded at multiple emission wavelengths, by a global decomposition technique, has allowed us to characterise the triplet populations associated with Photosystem I and Photosystem II of thylakoids in the green alga Chlamydomonas reinhardtii. Three triplet populations are observed at fluorescence emissions characteristic of Photosystem II, and their zero field splitting parameters have been determined. These are similar to the zero field parameters for the three Photosystem II triplets previously reported for spinach thylakoids, suggesting that they have a widespread occurrence in nature. None of these triplets have the zero field splitting parameters characteristic of the Photosystem II recombination triplet observed only under reducing conditions. Because these triplets are generated under non-reducing redox conditions, when the recombination triplet is undetectable, it is suggested that they may be involved in the photoinhibition of Photosystem II. At emission wavelengths characteristic of Photosystem I, three triplet populations are observed, two of which are attributed to the P(700) recombination triplet frozen in two different conformations, based on the microwave-induced fluorescence emission spectra and the triplet minus singlet difference spectra. The third triplet population detected at Photosystem I emission wavelengths, which was previously unresolved, is proposed to originate from the antenna chlorophyll of the core or the unusually blue-shifted outer antenna complexes of this organism. PMID:17161376

Santabarbara, Stefano; Agostini, Giancarlo; Casazza, Anna Paola; Syme, Christopher D; Heathcote, P; Böhles, Felix; Evans, Michael C W; Jennings, Robert C; Carbonera, Donatella

2007-01-01

433

Electrochemical Potential Gradients of H+, K+, Ca2+, and Cl- across the Tonoplast of the Green Alga Eremosphaera Viridis.  

PubMed Central

Using ion-selective microelectrodes, we measured the activity of H+, K+, Ca2+, and Cl- and the electrical potential both in the vacuole and in the cytoplasm of the unicellular green alga Eremosphaera viridis to obtain comparable values of the named parameters from the same object under identical conditions. The cytosol had a pH of 7.3, and activities of the other ions were 130 mM K+, 160 nM Ca2+, and 2.2 mM Cl-. We observed only small and transient light-dependent changes of the cytosolic Ca2+ activity. The vacuolar K+ activity did not differ significantly from the cytosolic one. The Ca2+ activity inside the vacuole was approximately 200 [mu]M, the pH was 5.0, and the Cl- activity was 6.2 mM. The concentrations of K+, Ca2+, and Cl- in cell extracts were measured by induction-coupled plasma spectroscopy and anion chromatography. This confirmed the vacuolar activities for K+ and Cl- obtained with ion-selective microelectrodes and indicated that approximately 60% of the vacuolar Ca2+ was buffered. The tonoplast potential was vanishingly low ([less than or equal to][plus or minus]2 mV). There was no detectable electrochemical potential gradient for K+ across the tonoplast, but there was, however, an obvious electrochemical potential gradient for Cl- (-26 mV), indicating an active accumulation of Cl- inside the vacuole. PMID:12228672

Bethmann, B.; Thaler, M.; Simonis, W.; Schonknecht, G.

1995-01-01

434

The genome of the diatom Thalassiosira pseudonana: Ecology,evolution, and metabolism  

SciTech Connect

Diatoms are unicellular algae with plastids acquired by secondary endosymbiosis. They are responsible for {approx}20% of global carbon fixation. We report the 34 Mbp draft nuclear genome of the marine diatom, Thalassiosira pseudonana and its 129 Kbp plastid and 44 Kbp mitochondrial genomes. Sequence and optical restriction mapping revealed 24 diploid nuclear chromosomes. We identified novel genes for silicic acid transport and formation of silica-based cell walls, high-affinity iron uptake, biosynthetic enzymes for several types of polyunsaturated fatty acids, utilization of a range of nitrogenous compounds and a complete urea cycle, all attributes that allow diatoms to prosper in the marine environment. Diatoms are unicellular, photosynthetic, eukaryotic algae found throughout the world's oceans and freshwater systems. They form the base of short, energetically-efficient food webs that support large-scale coastal fisheries. Photosynthesis by marine diatoms generates as much as 40% of the 45-50 billion tonnes of organic carbon produced each year in the sea (1), and their role in global carbon cycling is predicted to be comparable to that of all terrestrial rainforests combined (2, 3). Over geological time, diatoms may have influenced global climate by changing the flux of atmospheric carbon dioxide into the oceans (4). A defining feature of diatoms is their ornately patterned silicified cell wall or frustule, which displays species-specific nano-structures of such fine detail that diatoms have long been used to test the resolution of optical microscopes. Recent attention has focused on biosynthesis of these nano-structures as a paradigm for future silica nanotechnology (5). The long history (over 180 million years) and dominance of diatoms in the oceans is reflected by their contributions to vast deposits of diatomite, most cherts and a significant fraction of current petroleum reserves (6). As photosynthetic heterokonts, diatoms reflect a fundamentally different evolutionary history from the higher plants that dominate photosynthesis on land. Higher plants and green, red and glaucophyte algae are derived from a primary endosymbiotic event in which a non-photosynthetic eukaryote acquired a chloroplast by engulfing (or being invaded by) a prokaryotic cyanobacterium. In contrast, dominant bloom-forming eukaryotic phytoplankton in the ocean, such as diatoms and haptophytes, were derived by secondary endosymbiosis whereby a non-photosynthetic eukaryote acquired a chloroplast by engulfing a photosynthetic eukaryote, probably a red algal endosymbiont (Fig. 1). Each endosymbiotic event led to new combinations of genes derived from the hosts and endosymbionts (7). Prior to this project, relatively few diatom genes had been sequenced, few chromosome numbers were known, and genetic maps did not exist (8). The ecological and evolutionary importance of diatoms motivated our sequencing and analysis of the nuclear, plastid, and mitochondrial genomes of the marine centric diatom Thalassiosira pseudonana.

Ambrust, E.V.; Berges, J.; Bowler, C.; Green, B.; Martinez, D.; Putnam, N.; Zhou, S.; Allen, A.; Apt, K.; Bechner, M.; Brzezinski, M.; Chaal, B.; Chiovitti, A.; Davis, A.; Goodstein, D.; Hadi, M.; Hellsten,U.; Hildebrand, M.; Jenkins, B.; Jurka, J.; Kapitonov, V.; Kroger, N.; Lau, W.; Lane, T.; Larimer, F.; Lippmeier, J.; Lucas, S.; Medina, M.; Montsant, A.; Obornik, M.; Parker, M. Schnitzler; Palenik, B.; Pazour,G.; Richardson, P.; Rynearson, T.; Saito, M.; Schwartz, D.; Thamatrakoln,K.; Valentin, K.; Vardi, A.; Wilkerson, F.; Rokhsar, D.; Vardi, A.; Wilkerson, F.P.; Rokhsar, D.S.

2004-09-01

435

The Genome of the Diatom Thalassiosira Pseudonana: Ecology, Evolution and Metabolism  

SciTech Connect

Diatoms are unicellular algae with plastids acquired by secondary endosymbiosis. They are responsible for {approx}20% of global carbon fixation. We report the 34 Mbp draft nuclear genome of the marine diatom, Thalassiosira pseudonana and its 129 Kbp plastid and 44 Kbp mitochondrial genomes. Sequence and optical restriction mapping revealed 24 diploid nuclear chromosomes. We identified novel genes for silicic acid transport and formation of silica-based cell walls, high-affinity iron uptake, biosynthetic enzymes for several types of polyunsaturated fatty acids, utilization of a range of nitrogenous compounds and a complete urea cycle, all attributes that allow diatoms to prosper in the marine environment. Diatoms are unicellular, photosynthetic, eukaryotic algae found throughout the world's oceans and freshwater systems. They form the base of short, energetically-efficient food webs that support large-scale coastal fisheries. Photosynthesis by marine diatoms generates as much as 40% of the 45-50 billion tonnes of organic carbon produced each year in the sea (1), and their role in global carbon cycling is predicted to be comparable to that of all terrestrial rainforests combined (2, 3). Over geological time, diatoms may have influenced global climate by changing the flux of atmospheric carbon dioxide into the oceans (4). A defining feature of diatoms is their ornately patterned silicified cell wall or frustule, which displays species-specific nano-structures of such fine detail that diatoms have long been used to test the resolution of optical microscopes. Recent attention has focused on biosynthesis of these nano-structures as a paradigm for future silica nanotechnology (5). The long history (over 180 million years) and dominance of diatoms in the oceans is reflected by their contributions to vast deposits of diatomite, most cherts and a significant fraction of current petroleum reserves (6). As photosynthetic heterokonts, diatoms reflect a fundamentally different evolutionary history from the higher plants that dominate photosynthesis on land. Higher plants and green, red and glaucophyte algae are derived from a primary endosymbiotic event in which a non-photosynthetic eukaryote acquired a chloroplast by engulfing (or being invaded by) a prokaryotic cyanobacterium. In contrast, dominant bloom-forming eukaryotic phytoplankton in the ocean, such as diatoms and haptophytes, were derived by secondary endosymbiosis whereby a non-photosynthetic eukaryote acquired a chloroplast by engulfing a photosynthetic eukaryote, probably a red algal endosymbiont (Fig. 1). Each endosymbiotic event led to new combinations of genes derived from the hosts and endosymbionts (7). Prior to this project, relatively few diatom genes had been sequenced, few chromosome numbers were known, and genetic maps did not exist (8). The ecological and evolutionary importance of diatoms motivated our sequencing and analysis of the nuclear, plastid, and mitochondrial genomes of the marine centric diatom Thalassiosira pseudonana.

Armbrust, E V; Berges, J A; Bowler, C; Green, B R; Martinez, D; Putnam, N H; Zhou, S; Allen, A E; Apt, K E; Bechner, M; Brzezinski, M A; Chaal, B K; Chiovitti, A; Davis, A K; Demarest, M S; Detter, J C; del Rio, T G; Goodstein, D; Hadi, M Z; Hellsten, U; Hildebrand, M; Jenkins, B D; Jurka, J; Kapitonov, V V; Kroger, N; Lau, W Y; Lane, T W; Larimer, F W; Lippmeier, J C; Lucas, S; Medina, M; Montsant, A; Obornik, M; Parker, M S; Palenik, B; Pazour, G J; Richardson, P M; Rynearson, T A; Saito, M A; Schwartz, D C; Thamatrakoln, K; Valentin, K; Vardi, A; Wilkerson, F P; Rokhsar, D S

2005-11-14

436

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

437

De novo transcriptomic analysis of hydrogen production in the green alga Chlamydomonas moewusii through RNA-Seq  

PubMed Central

Background Microalgae can make a significant contribution towards meeting global renewable energy needs in both carbon-based and hydrogen (H2) biofuel. The development of energy-related products from algae could be accelerated with improvements in systems biology tools, and recent advances in sequencing technology provide a platform for enhanced transcriptomic analyses. However, these techniques are still heavily reliant upon available genomic sequence data. Chlamydomonas moewusii is a unicellular green alga capable of evolving molecular H2 under both dark and light anaerobic conditions, and has high hydrogenase activity that can be rapidly induced. However, to date, there is no systematic investigation of transcriptomic profiling during induction of H2 photoproduction in this organism. Results In this work, RNA-Seq was applied to investigate transcriptomic profiles during the dark anaerobic induction of H2 photoproduction. 156 million reads generated from 7 samples were then used for de novo assembly after data trimming. BlastX results against NCBI database and Blast2GO results were used to interpret the functions of the assembled 34,136 contigs, which were then used as the reference contigs for RNA-Seq analysis. Our results indicated that more contigs were differentially expressed during the period of early and higher H2 photoproduction, and fewer contigs were differentially expressed when H2-photoproduction rates decreased. In addition, C. moewusii and C. reinhardtii share core functional pathways, and transcripts for H2 photoproduction and anaerobic metabolite production were identified in both organisms. C. moewusii also possesses similar metabolic flexibility as C. reinhardtii, and the difference between C. moewusii and C. reinhardtii on hydrogenase expression and anaerobic fermentative pathways involved in redox balancing may explain their different profiles of hydrogenase activity and secreted anaerobic metabolites. Conclusions Herein, we have described a workflow using commercial software to analyze RNA-Seq data without reference genome sequence information, which can be applied to other unsequenced microorganisms. This study provided biological insights into the anaerobic fermentation and H2 photoproduction of C. moewusii, and the first transcriptomic RNA-Seq dataset of C. moewusii generated in this study also offer baseline data for further investigation (e.g. regulatory proteins related to fermentative pathway discussed in this study) of this organism as a H2-photoproduction strain. PMID:23971877

2013-01-01

438

Enzymatic hydrolysis and production of bioethanol from common macrophytic green alga Ulva fasciata Delile.  

PubMed

The green seaweed Ulva which proliferates fast and occurs abundantly worldwide was used as a feedstock for production of ethanol following enzymatic hydrolysis. Among the different cellulases investigated for efficient saccharification, cellulase 22119 showed the highest conversion efficiency of biomass into reducing sugars than Viscozyme L, Cellulase 22086 and 22128. Pre-heat treatment of biomass in aqueous medium at 120°C for 1h followed by incubation in 2% (v/v) enzyme for 36 h at 45°C gave a maximum yield of sugar 206.82±14.96 mg/g. The fermentation of hydrolysate gave ethanol yield of 0.45 g/g reducing sugar accounting for 88.2% conversion efficiency. These values are substantially higher than those of reported so far for both agarophytes and carrageenophytes. It was also confirmed that enzyme can be used twice without compromising on the saccharification efficiency. The findings of this study reveal that Ulva can be a potential feedstock for bioethanol production. PMID:24157682

Trivedi, Nitin; Gupta, Vishal; Reddy, C R K; Jha, Bhavanath

2013-12-01

439

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

440

UNUSUAL PHENOLIC COMPOUNDS CONTRIBUTE TO ECOPHYSIOLOGICAL PERFORMANCE IN THE PURPLE-COLORED GREEN ALGA ZYGOGONIUM ERICETORUM (ZYGNEMATOPHYCEAE, STREPTOPHYTA) FROM A HIGH-ALPINE HABITAT  

PubMed Central

The filamentous green alga Zygogonium ericetorum (Zygnematophyceae, Streptophyta) was collected in a high-alpine rivulet in Tyrol, Austria. Two different morphotypes of this alga were found: a purple morph with a visible purple vacuolar content and a green morph lacking this coloration. These morphotypes were compared with respect to their secondary metabolites, ultrastructure, and ecophysiological properties. Colorimetric tests with aqueous extracts of the purple morph indicated the presence of soluble compounds such as phenolics and hydrolyzable tannins. High-performance liquid chromatography-screening showed that Z. ericetorum contained several large phenolic peaks with absorption maxima at ?280 nm and sometimes with minor maxima at ?380 nm. Such compounds are uncommon for freshwater green microalgae, and could contribute to protect the organism against increased UV and visible (VIS) irradiation. The purple Z. ericetorum contained larger amounts (per dry weight) of the putative phenolic substances than the green morph; exposure to irradiation may be a key factor for accumulation of these phenolic compounds. Transmission electron microscopy of the purple morph showed massive vacuolization with homogenous medium electron-dense content in the cell periphery, which possibly contains the secondary compounds. In contrast, the green morph had smaller, electron-translucent vacuoles. The ecophysiological data on photosynthesis and desiccation tolerance indicated that increasing photon fluence densities led to much higher relative electron transport rates (rETR) in the purple than in the green morph. These data suggest that the secondary metabolites in the purple morph are important for light acclimation in high-alpine habitats. However, the green morph recovered better after 4 d of rehydration following desiccation stress.

Aigner, Siegfried; Remias, Daniel; Karsten, Ulf; Holzinger, Andreas

2013-01-01

441

Phytohormones as regulators of heavy metal biosorption and toxicity in green alga Chlorella vulgaris (Chlorophyceae).  

PubMed

The present study was undertaken to test the influence of exogenously applied phytohormones: auxins (IAA, IBA, NAA, PAA), cytokinins (BA, CPPU, DPU, 2iP, Kin, TDZ, Z), gibberellin (GA(3)), jasmonic acid (JA) as well as polyamine - spermidine (Spd) upon the growth and metabolism of green microalga Chlorella vulgaris (Chlorophyceae) exposed to heavy metal (Cd, Cu, Pb) stress. The inhibitory effect of heavy metals on algal growth, metabolite accumulation and enzymatic as well as non-enzymatic antioxidant system was arranged in the following order: Cd > Pb > Cu. Exogenously applied phytohormones modify the phytotoxicity of heavy metals. Auxins, cytokinins, gibberellin and spermidine (Spd) can alleviate stress symptoms by inhibiting heavy metal biosorption, restoring algal growth and primary metabolite level. Moreover, these phytohormones and polyamine stimulate antioxidant enzymes' (superoxide dismutase, ascorbate peroxidase, catalase) activities and ascorbate as well as glutathione accumulation by producing increased antioxidant capacity in cells growing under abiotic stress. Increased activity of antioxidant enzymes reduced oxidative stress expressed by lipid peroxidation and hydrogen peroxide level. In contrast JA enhanced heavy metal toxicity leading to increase in metal biosorption and ROS generation. The decrease in cell number, chlorophylls, carotenoids, monosaccharides, soluble proteins, ascorbate and glutathione content as well as antioxidant enzyme activity was also obtained in response to JA and heavy metals. Determining the stress markers (lipid peroxidation, hydrogen peroxide) and antioxidants' level as well as antioxidant enzyme activity in cells is important for understanding the metal-specific mechanisms of toxicity and that these associated novel endpoints may be useful metrics for accurately predicting toxicity. The data suggest that phytohormones and polyamine play an important role in the C. vulgaris responding to abiotic stressor and algal adaptation ability to metal contamination of aquatic environment. PMID:22305067

Piotrowska-Niczyporuk, Alicja; Bajguz, Andrzej; Zambrzycka, El?bieta; Godlewska-?y?kiewicz, Beata

2012-03-01

442

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 (?4 nM) 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

443

Evaluation of an oil-producing green alga Chlorella sp. C2 for biological DeNOx of industrial flue gases.  

PubMed

NOx, a significant portion of fossil fuel flue gases, are among the most serious environmental issues in the world and must be removed in an additional costly gas treatment step. This study evaluated the growth of the green alga Chlorella sp. C2 under a nitrite-simulated NOx environment and the removal rates of actual flue gas fixed salts (FGFSs) from Sinopec's Shijiazhuang refinery along with lipid production. The results showed that nitrite levels lower than 176.5 mM had no significant adverse effects on the cell growth and photosynthesis of Chlorella sp. C2, demonstrating that this green alga could utilize nitrite and NOx as a nitrogen source. High concentrations of nitrite (88.25-176.5 mM) also resulted in the accumulation of neutral lipids. A 60% nitrite removal efficiency was obtained together with the production of 33% algae lipids when cultured with FGFS. Notably, the presence of nitrate in the FGFS medium significantly enhanced the nitrite removal capability, biomass and lipid production. Thus, this study may provide a new insight into the economically viable application of microalgae in the synergistic combination of biological DeNOx of industrial flue gases and biodiesel production. PMID:25105531

Zhang, Xin; Chen, Hui; Chen, Weixian; Qiao, Yaqin; He, Chenliu; Wang, Qiang

2014-09-01

444

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

445

Laboratory Assessment of Altered Atmospheric Carbon Dioxide on Filamentous Green Algae Phenolic Content and Caddisfly Growth and Survival  

Microsoft Academic Search

To test global change effects on lentic ecosystems, we examined I) if algae phenolic content was influenced by CO treatments, and 2) if algivores fed CO-treated algae were impacted. Four common Chlorophytes (Cladophora glomerata, Spirogyra grevilleana, Ulothrix, fimbriata, and Zygnema sp.) were grown under three atmospheric carbon dioxide environments (200, 360, and 3000 mg\\/L). Algivore (the microcaddisfly Hydroptila waubesiana [Trichoptera:

A. K. Swanson; S. Hrinda; J. B. Keiper

2007-01-01

446

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 153.46 KDa, 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

447

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

448

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 filament