Note: This page contains sample records for the topic green algae diatoms from Science.gov.
While these samples are representative of the content of Science.gov,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of Science.gov
to obtain the most current and comprehensive results.
Last update: November 12, 2013.
1

Combined exposure to hydrogen peroxide and light--selective effects on cyanobacteria, green algae, and diatoms.  

PubMed

The selective toxicity of H2O2 was investigated to develop a potential tool for limiting cyanobacterial blooms and to better understand the occurrence of cyanobacteria and other phytoplankton species in relation to reactive oxygen species in surface waters. The cyanobacterium Microcystis aeruginosa, the green alga Pseudokirchneriella subcapitata, and the diatom Navicula seminulum were tested under pulse exposure to H202 in the dark and at various irradiances. H2O2 was decomposed at rates depending on algal species and was proportional to irradiance. The cyanobacterium was affected by H202 at 10 times lower concentrations than green alga and diatom, and a strong light-dependent toxicity enhanced the difference. The inhibition was measured as photosynthetic yield (Fv/Fm) in pulse amplitude modulated fluorometry, and was confirmed by changes in minimal fluorescence (F0) and photosynthetic oxygen evolution. Single doses of 0.27 mg L(-1) of H202 caused 50% inhibition to M. aeruginosa at high irradiance. Such concentration overlaps with the highest levels of 0.34 mg L(-1) observed in natural waters, suggesting that H202 may act as a limiting factor for cyanobacterial growth. PMID:17265964

Drábková, Michaela; Admiraal, Wim; Marsálek, Blahoslav

2007-01-01

2

Recovery of photosynthesis and growth rate in green, blue-green, and diatom algae after exposure to atrazine.  

PubMed

We evaluated the recovery of photosynthesis and growth rate in green (Pseudokirchneriella subcapitata), blue-green (Anabaena flos-aquae), and diatom (Navicula pelliculosa) algae after pulsed exposure to atrazine. Subsequent to a grow-up period of 24 to 72 h to establish requisite cell density for adequate signal strength to measure photosystem II (PSII) quantum yield, algae were exposed to a pulse of atrazine for 48 h followed by a 48-h recovery period in control media. Photosynthesis was measured at 0, 3, 6, 12, 24, and 48 h of the exposure and recovery phases using pulse amplitude modulation fluorometry; growth rate and cell density were also concomitantly measured at these time points. Exposure to atrazine resulted in immediate, but temporary, inhibition of photosynthesis and growth; however, these effects were transient and fully reversible in the tested species of algae. For all three algal species, no statistically significant reductions (p ? 0.05) in growth rate or PSII quantum yield were detected at any of the treatment concentrations 48 h after atrazine was removed from the test system. Effects at test levels up to the highest tested exposure levels were consequently determined to be algistatic (reversible). Both biochemically and physiologically, recovery of photosynthesis and growth rate occur immediately, reaching control levels within hours following exposure. Therefore, pulsed exposure profiles of atrazine typically measured in Midwestern U.S. streams are unlikely to result in biologically meaningful changes in primary production given that the effects of atrazine are temporary and fully reversible in species representative of native populations. PMID:22903862

Brain, Richard A; Arnie, Joshua R; Porch, John R; Hosmer, Alan J

2012-09-07

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

2011-11-07

4

Comparison of the Fouling Release Properties of Hydrophobic Fluorinated and Hydrophilic PEGylated Block Copolymer Surfaces:  Attachment Strength of the Diatom Navicula and the Green Alga Ulva  

Microsoft Academic Search

To understand the role of surface wettability in adhesion of cells, the attachment of two different marine algae was studied on hydrophobic and hydrophilic polymer surfaces. Adhesion of cells of the diatom NaVicula and sporelings (young plants) of the green macroalga UlVa to an underwater surface is mainly by interactions between the surface and the adhesive exopolymers, which the cells

Sitaraman Krishnan; Nick Wang; Christopher K. Ober; John A. Finlay; Maureen E. Callow; James A. Callow; Alexander Hexemer; Karen E. Sohn; Edward J. Kramer; Daniel A. Fischer

2006-01-01

5

Do diatom algae frustules accumulate uranium?  

Microsoft Academic Search

Neutron Activation Analysis (NAA) and Synchrotron Radiation X-ray Fluorescent Analysis (SRXRFA) were used to measure the content of uranium and a few other trace elements in samples of bottom sediments of Lake Baikel separated into biogenic (diatom algae frustules) and clastic components by an aerodynamic method. Uranium is rejected, rather than accumulated by diatom algae frustules.

E. L. Goldberg; M. A. Grachev; V. A. Bobrov; A. V. Bessergenev; B. V. Zolotaryov; Ye. V. Likhoshway

1998-01-01

6

The effect of naphthalene-acetic acid on biomass productivity and chlorophyll content of green algae, coccolithophore, diatom, and cyanobacterium cultures.  

PubMed

The application of biochemical stimulants to enhance biomass and metabolite productivity is being investigated here and may be a simpler approach to achieve our goals of higher productivity and lower costs than methods such as genetic modification. The research builds on prior work of screening various biochemical stimulants representing different types of plant growth regulators with the green alga, Chlorella sorokiniana. Here, we report the impact on biomass and chlorophyll productivity by comparing the delivery method of a previously identified superior stimulant, the synthetic auxin naphthalene-acetic acid (NAA), solubilized in ethanol or methanol. Algae evaluated included the green alga, C. sorokiniana, as well as a mixed consortium that includes C. sorokiniana along with two other wild-isolated green algae, Scenedesmus bijuga and Chlorella minutissima. It was found that NAA dissolved in ethanol was more effective in enhancing biomass productivity of C. sorokiniana. However, no differences were observed with the mixed consortia. The most effective treatment from this step, EtOH(500ppm)?+?NAA(5ppm), along with two other NAA concentrations (EtOH(500ppm)?+?NAA(2.5ppm) and EtOH(500ppm)?+?NAA(10ppm)), was then applied to six diverse species of microalgae to determine if the treatment dosage was effective for other freshwater and marine green algae, cyanobacteria, coccolithophore, and diatoms. It was found that three of the species bioassayed, Pleurochrysis carterae, C. sorokiniana, and Haematococcus pluvialis exhibited a substantial boost in biomass productivity over the 10-day growth period. The use of ethanol and NAA at a combined dosage of EtOH(500ppm)?+?NAA(5ppm) was found to generate the highest biomass productivity for each of the species that responded positively to the treatments. If scalable, NAA and ethanol may have the potential to lower production costs by increasing biomass yields for commercial microalgae cultivation. PMID:21431321

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

2011-03-23

7

Temperature and Manganese as Determining Factors in the Presence of Diatom or Blue-Green Algal Floras in Streams  

Microsoft Academic Search

Diatoms are usually the major component of the algal flora in many streams, although green and blue-green algae may be present. These experiments were designed to determine if high temperature or a shift in the chemical composition of the water might bring about a dominance of blue-green algae and\\/or green algae rather than a dominance of diatoms in the algal

Ruth Patrick; Bowman Crum; John Coles

1969-01-01

8

Hydrogen production by photosynthetic green algae.  

PubMed

Oxygenic photosynthetic organisms such as cyanobacteria, green algae and diatoms are capable of absorbing light and storing up to 10-13% of its energy into the H-H bond of hydrogen gas. This process, which takes advantage of the photosynthetic apparatus of these organisms to convert sunlight into chemical energy, could conceivably be harnessed for production of significant amounts of energy from a renewable resource, water. The harnessed energy could then be coupled to a fuel cell for electricity generation and recycling of water molecules. In this review, current biochemical understanding of this reaction in green algae, and some of the major challenges facing the development of future commercial algal photobiological systems for H2 production have been discussed. PMID:17133763

Ghirardi, Maria L

2006-08-01

9

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

10

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

PubMed Central

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

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

2011-01-01

11

Marine diatom, Navicula sp. strain JPCC DA0580 and marine green alga, Chlorella sp. strain NKG400014 as potential sources for biodiesel production.  

PubMed

Marine diatom, strain JPCC DA0580, and marine green microalga strain NKG400014 were selected as high neutral lipid-producers from marine microalgal culture collection toward biodiesel production. These strains were tentatively identified as Navicula sp. and Chlorella sp., respectively, by 18S rDNA analysis. Growth and lipid accumulation conditions of both strains were analyzed by changing nutrient concentrations in growth media and initial illuminance intensity. The highest productivity of fatty acid methyl ester (FAME) reached to 154 mg/L/week for NKG400014 and 185 mg/L/week for JPCC DA0580. Gas chromatography/mass spectrometry analysis indicates that FAME fraction from NKG400014 mainly contained 9-12-15-octadecatrienoate (C18:3) and that from JPCC DA0580 mainly contained methyl palmitate (C16:0) and methyl palmitoleate (C16:1). Furthermore, calorimetric analysis revealed that the energy content of strain was 4,233 +/- 55 kcal/kg (i.e., 15.9 +/- 0.2 MJ/kg) for NKG400014 and 6,423 +/- 139 kcal/mg (i.e., 26.9 +/- 0.6 MJ/kg) for JPCC DA0580, respectively. The value from JPCC DA0580 was equivalent to that of coal. The strains NKG400014 and JPCC DA0580 will become a promising resource that can grow as dominant species in the open ocean toward production of both liquid and solid biofuels. PMID:19756412

Matsumoto, Mitsufumi; Sugiyama, Hiroshi; Maeda, Yoshiaki; Sato, Reiko; Tanaka, Tsuyoshi; Matsunaga, Tadashi

2009-09-08

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

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

PubMed Central

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

Patrick, Ruth; Crum, Bowman; Coles, John

1969-01-01

14

Hierarchical and Size Dependent Mechanical Properties of Silica and Silicon Nanostructures Inspired by Diatom Algae.  

National Technical Information Service (NTIS)

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 mechanical defense from predators ...

A. P. Garcia

2010-01-01

15

Characterization of the Lhc SR Gene Under Light and Temperature Stress in the Green Alga Ulva linza  

Microsoft Academic Search

As a green-tide-forming macroalga, Ulva linza is distributed worldwide and therefore subject to various environmental stresses. The LHCSR (also known as LI818 in green\\u000a alga and LHCX in diatoms) protein is a stress-related member of the LHC family that plays an important role in photo-protective\\u000a mechanism, which has been only found in algae. In this study, we cloned full-length cDNA

Meitao Dong; Xiaowen Zhang; Zhimeng Zhuang; Jian Zou; Naihao Ye; Dong Xu; Shanli Mou; Chengwei Liang; Wenqi Wang

16

Peroxisomal targeting signals in green algae.  

PubMed

Peroxisomal enzymatic proteins contain targeting signals (PTS) to enable their import into peroxisomes. These targeting signals have been identified as PTS1 and PTS2 in mammalian, yeast, and higher plant cells; however, no PTS2-like amino acid sequences have been observed in enzymes from the genome database of Cyanidiochyzon merolae (Bangiophyceae), a primitive red algae. In studies on the evolution of PTS, it is important to know when their sequences came to be the peroxisomal targeting signals for all living organisms. To this end, we identified a number of genes in the genome database of the green algae Chlamydomonas reinhardtii, which contains amino acid sequences similar to those found in plant PTS. In order to determine whether these sequences function as PTS in green algae, we expressed modified green fluorescent proteins (GFP) fused to these putative PTS peptides under the cauliflower mosaic virus 35S promoter. To confirm whether granular structures containing GFP-PTS fusion proteins accumulated in the peroxisomes of Closterium ehrenbergii, we observed these cells after the peroxisomes were stained with 3, 3'-diaminobenzidine. Our results confirm that the GFP-PTS fusion proteins indeed accumulated in the peroxisomes of these green algae. These findings suggest that the peroxisomal transport system for PTS1 and PTS2 is conserved in green algal cells and that our fusion proteins can be used to visualize peroxisomes in live cells. PMID:19214701

Shinozaki, Akiko; Sato, Nagisa; Hayashi, Yasuko

2009-02-12

17

Gametogenesis in the green alga Oedogonium cardiacum  

Microsoft Academic Search

Summary Spermiogenesis in the macandrous, filamentous green algaOedogonium cardiacum is described at the ultrastructural level. The formation of the flagellar apparatus is similar to that in zoosporogenesis. Centrioles, appearingde novo in extranuclear, electron dense material, proliferate into two rows around the nucleus. Rootlet templates concurrently form between adjacent centrioles. The two rows migrate to the side of the cell and

Ronald A. Coss; Jeremy D. Pickett-Heaps

1974-01-01

18

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

19

Underwater fertilization dynamics of marine green algae  

Microsoft Academic Search

We studied the fertilization dynamics of marine green algae with both analytical methods and numerical simulations. In this study, we focused on a new factor, gametic investment per unit volume of the space in which gametes searched for their partners, and compared the numbers of zygotes formed at lower investments with those at higher investments. As a function of the

Tatsuya Togashi; Paul Alan Cox; John L. Bartelt

2007-01-01

20

Environmental Requirements of Blue-Green Algae.  

National Technical Information Service (NTIS)

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

1967-01-01

21

The taxonomy of blue-green algae  

Microsoft Academic Search

The conventions at present used in the classification of blue-green algae frequently prove unsatisfactory. A solution is suggested which requires the simultaneous use of two different approaches. When a binomial is essential the flora of Geitler (1932) should be adequate for most purposes, but any long term attempt to sort out the present chaos will require the use of numerical

B. A. Whitton

1969-01-01

22

Photooxidative Death in Blue-Green Algae  

PubMed Central

When incubated in the light under 100% oxygen, wild-type blue-green algae (Anacystis nidulans, Synechococcus cedrorum) die out rapidly at temperatures of 4 to 15 C, and at 35 C (or at 26 C in the case of S. cedrorum) in the absence of CO2. Photosynthesis is impaired in these cells long before they die. Blocking of photosystem II at high temperatures in the presence of CO2 sensitizes the algae to photooxidative death. Photooxidative death and bleaching of photosynthetic pigments are separable phenomena. Photooxidative conditions were demonstrated in Israeli fish ponds using A. nidulans as the test organism during dense summer blooms, when dissolved CO2 is low, and in winter, when water temperatures generally drop below 15 C. This finding suggests that photooxidative death may be responsible for the sudden decomposition of blue-green blooms in summer, and may be a factor in the absence of blue-green blooms in winter.

Abeliovich, A.; Shilo, M.

1972-01-01

23

The peculiar distribution of class I and class II aldolases in diatoms and in red algae  

Microsoft Academic Search

Diatom plastids probably evolved by secondary endocytobiosis from a red alga that was up by a eukaryotic host cell. Apparently,\\u000a this process increased the complexity of the intracellular distribution of metabolic enzymes. We identified genes encoding\\u000a fructose-bisphosphate aldolases (FBA) in two centric (Odontella sinensis, Thalassiosira pseudonana) and one pennate (Phaeodactylum tricornutum) diatoms and found that four different aldolases are present

Peter G. Kroth; Yvonne Schroers; Oliver Kilian

2005-01-01

24

Studies with deoxyribonucleic acid from blue-green algae  

Microsoft Academic Search

The total DNA in species of blue-green algae is similar to that of bacteria on an individual cell, but not on a dry weight, basis. The % G+C content of DNA from four species of blue-green algae has been determined by melting temperature measurement. An attempt tomeasure genetic homology between blue-green algae and certain bacterial species is described.

I. W. Craig; C. K. Leach; N. G. Carr

1969-01-01

25

The chloroplast pigments of some green and yellow-green algae  

Microsoft Academic Search

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

S. J. Whittle; P. J. Casselton

1969-01-01

26

Respiration in Blue-Green Algae  

PubMed Central

The low rate of endogenous respiration exhibited by the blue-green algae Anacystis nidulans and Phormidium luridum was not increased by the addition of respiratory substrates. However, endogenous respiration was inhibited by low concentrations of cyanide and by high carbon monoxide tensions. In addition, the uncouplers dinitrophenol and carbonyl cyanide p-trifluoromethoxyphenylhydrazone both stimulated the respiratory rate. The transition of cells from the aerobic steady state to anaerobiosis was accompanied by a decrease in the concentration of cellular nicotinamide adenine dinucleotide phosphate (NADP+) and adenosine triphosphate (ATP), whereas the concentration of nicotinamide adenine dinucleotide (NAD+) was unchanged. Concomitant with the metabolite decreases were stoichiometric increases io reduced NADP+ (NADPH), adenosine diphosphate, and adenosine monophosphate. A decrease in ATP was also observed after the addition of uncouplers. These data are interpreted as evidence for the association of oxidative phosphorylation with the oxidation of NADP+-linked substrates in these algae. Membrane fragments isolated from the algal cells oxidized succinate, malate, ferrocytochrome c, ascorbate-tetramethyl-p-phenylenediamine, and reduced 2,6-dichlorophenol indophenol but did not oxidize NADPH or reduced NAD+ in a cyanide-sensitive system. Oxidative phosphorylation has not yet been demonstrated in these fragments, but a dark ATP-Pi exchange, distinct from the lighttriggered exchange associated with photosynthesis, is readily observed. This exchange was inhibited by phloridzin, Atabrine, and uncouplers in concentrations which suggest that the mechanism of oxidative phosphorylation in blue-green algae is different from that found in other bacteria and in mitochondria. These results led to the conclusion that the biochemical basis for obligate autotrophy in these organisms does not lie in the metabolic events associated with terminal electron transport and energy conservation.

Biggins, John

1969-01-01

27

Screening of different algae for green synthesis of gold nanoparticles  

Microsoft Academic Search

The cyanobacteria Phormidium valderianum, P. tenue and Microcoleus chthonoplastes and the green algae Rhizoclonium fontinale, Ulva intestinalis, Chara zeylanica and Pithophora oedogoniana were exposed to hydrogen tetrachloroaurate solution and were screened for their suitability for producing nano?gold. All three cyanobacteria genera and two of the green algae (Rhizoclonium fontinale and Ulva intestinalis) produced gold nanoparticles intracellularly, confirmed by purple colouration

Dipannita Parial; Hirak K. Patra; Anjan K. R. Dasgupta; Ruma Pal

2012-01-01

28

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

29

Chapter 9 Electrical events in photomovement of green flagellated algae  

Microsoft Academic Search

Phototaxis and photophobic responses in green flagellated algae are mediated by a rhodopsin-type photoreceptor. Its photoexcitation triggers a rapid cascade of electrical phenomena in the cell membrane. The photoinduced electrical responses in green flagellated algae can be recorded extracellularly from an individual cell by a suction pipette technique, or from a cell suspension. Photoexcitation leads to the onset of a

Oleg A. Sineshchekov; Elena G. Govorunova

2001-01-01

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

2007-02-02

31

Freshwater Cyanobacteria (Blue-Green Algae) Toxins: Isolation and Characterization.  

National Technical Information Service (NTIS)

Biotoxins of freshwater blue-green algae (cyanobacteria) are currently classed as being either hepatotoxic peptides or neurotoxic alkaloids. This study is concerned with the examination of toxins from the species Anabaena flos-aquae, Aphanizomenon flos-aq...

W. W. Carmichael

1985-01-01

32

Viable Cyanobacteria and Green Algae from the Permafrost Darkness  

Microsoft Academic Search

This review represents an overview of the existence, distribution and abundance of the photoautotrophic microorganisms in\\u000a the deep subsurface permafrost of the Northeast Russia and McMurdo Dry Valleys, Antarctica. The morphology, growth rate, spectral\\u000a properties, phylogenetic position of the viable permafrost green algae and cyanobacteria have been studied. Viable photoautotrophs\\u000a were represented by unicellular green algae and filamentous cyanobacteria with

Tatiana A. Vishnivetskaya; Tatiana A

2009-01-01

33

Identification of cytokinin in a green algae extract  

NASA Astrophysics Data System (ADS)

Isopentenyladenosine (i6Ado) was identified, and trans-zeatin (trans-Z) and trans-zeatin riboside (trans-ZR) were detected by high pressure liquid chromatography (HPLC) but not verified with chromatography—mass spectrometry (GC-MS) analysis of cytokinin from the extracts of green algae ( Ulva pertusa (Kjellm), Enteromopha compressa and Monostroma sp.). This indicated that the green algae mixture contained cytokinin—like substances.

de-Lin, Duan; Feng, Pan; Li, Shuai; Jun-Shun, Zhang; Xin-Tong, Liu; Xiu-Geng, Fei

1996-06-01

34

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

PubMed Central

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

Lang, Douglas S.; Brown, Edward J.

1981-01-01

35

Properties of phosphatases from green alga Scenedesmus incrassatulus Bahlin and blue-green alga Synechococcus aeruginosus Nag  

Microsoft Academic Search

Studies on phosphatases (acid and alkaline) inSynechococcus aeruginosus, a prokaryotic blue-green alga, andScenedesmus incrassatulus, an eukaryotic green alga under different conditions revealed that the acid phosphatase exhibited maximum activity to pH\\u000a 4·7 and 37°C in both the algae while alkaline phosphatase displayed greatest activity at 37·5°C and 10 pH inSynechococcus aeruginosus and at 10·6 pH and 37·5°C inScenedesmus incrassatulus. TheK

T R K Reddy; R Lakshminarayana

1988-01-01

36

The species composition and distribution of diatom algae in sphagnum bogs in European Russia: The Polistovo-Lovatskii land tract  

Microsoft Academic Search

The species composition of diatom algae in the Polistovo-Lovatskii sphagnum tract (Rdeiskoye bog, Novgorod oblast) \\\\are studied.\\u000a The systematic and ecological-geographical analyses of the flora are performed. A total of 256 species and intraspecific taxa\\u000a differing in ecological specificities and frequencies of occurrence in samples are revealed. A considerable number of centric\\u000a diatoms is found. It is shown that primary

M. S. Kulikovskiy

2009-01-01

37

Photobiological hydrogen production in green algae and photosynthetic bacteria  

Microsoft Academic Search

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

Greenbaum

1986-01-01

38

Green algae to land plants: An evolutionary transition  

Microsoft Academic Search

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

Linda E. Graham

1996-01-01

39

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

40

[Competition of two marine diatom algae for urea and nitrate nitrogen under three levels of irradiance].  

PubMed

Biomass dynamics of the plankton diatoms Thalassiosira weissflogii and Pseudo-nitzschia delicatissima were analyzed in batch mono- and mixed cultures grown on media with urea or nitrate as the sources of nitrogen, under irradiance 13, 38, and 115 microE/(m(2) x s). At the initial enrichment, nitrogen concentration was 0.18 mmol, and the nitrogen : phosphorus ratio was 5 : 1. The mechanisms of competition for the limiting resource satisfactorily described the interactions between the algae grown on urea. Competitive ability of algae was characterised according to the value of competitive eddect (CE), which was calculated as the ratio of growth rate and accumulated biomass decrease in mixed culture to that in monoculture CE of algae grown on urea increased with the increasing of irradiance and was lower than that of algae grown on nitrate. CE of P. delicatissima was higher than that T. weissflogii, independently of the source of nigrogen and the level of irradiance. At 38 and 115 microE/(m(2) x s) the growth of T. weissflogii ceased earlier than that of P. delicatissima, independently of the source o nitrogen. At 13 microE/(m(2) x s) the growth of P. delicatissima ceased earlier than of T. weissflogii in on cultures grown urea, but the growth of T. weissflogii was the first to cease on nitrate. The competition revealed in experimental communities for the nitrogen of urea between plankton algae gives reasons to suggest that in natural communities plankton algae also compere under inorganic nitrogen deficiency and organic nitrogen abundance. PMID:17205793

Il'iash, L V; Zapara, E V

41

Nitrate reductase of green algae is located in the pyrenoid.  

PubMed

Antibodies against nitrate reductase from Monoraphidium braunii have been used to determine the antigenic relationships of nitrate reductases from different green algae. Nitrate reductases from Chlamydomonas reinhardii, Chlorella fusca, Dunaliella salina, and Scenedesmus obliquus, were inhibited by, and cross-reacted with, antibodies raised against the enzyme from Monoraphidium braunii.These antibodies were also used to determine, by immunoelectron microscopy, the intracellular location of nitrate reductase in the aforementioned green algae. In all cases, the enzyme was specifically located in the pyrenoid. PMID:16664519

Lopez-Ruiz, A; Verbelen, J P; Roldan, J M; Diez, J

1985-12-01

42

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

43

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

Microsoft Academic Search

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

Ulf Karsten; Fabio Rindi

2010-01-01

44

A numerical analysis of counts of diatom frustules, and other algae, in water samples from the River Wey  

Microsoft Academic Search

During May 1978, samples of water were collected from 24 sites on, or associated with, the River Wey between its source south of Haslemere and Send just downstream of Guildford (approx. 57.5 km). Counts of diatom frustules, and other algae surviving the sampling technique, were analyzed by numerical taxonomic techniques. On the basis of community structure, the river was clearly

M. O. Moss; T. N. Bryant

1985-01-01

45

Differential sensitivity of green algae to allelopathic substances from Chara  

Microsoft Academic Search

Three short-term laboratory experiments were conducted to investigate allelopathic effects of a mixture of Chara globularis var. globularis Thuillier and Chara contraria var. contraria A. Braun ex Kützing on three different green algae. Single phytoplankton species were exposed to filtered water originating from charophyte cultures. Phytoplankton growth was monitored by determination of chlorophyll concentrations in batch cultures. The change in

G. Mulderij; E. Van Donk; J. G. M. Roelofs

2003-01-01

46

Bioactive natural products from blue-green algae  

Microsoft Academic Search

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

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

1994-01-01

47

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. TEYSSÈDRE'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 TEYSSÈDRE

2006-01-01

48

Marine blue-green algae have a unique osmoregulatory system  

Microsoft Academic Search

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

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

1983-01-01

49

Rapid Biopolymerisation During Wound Plug Formation in Green Algae  

Microsoft Academic Search

Organisms living in the marine environment contain a number of primary and secondary metabolites which are involved in bioadhesive processes. Much progress has been made regarding the characterization of underwater adhesive structures utilized by sessile invertebrates such as barnacles, mussels, and tubeworms. The structural components and biochemical mechanisms involved in the wound-plug forming process in marine siphonous green algae have

Matthew Welling; Georg Pohnert; Frithjof C. Küpper; Cliff Ross

2009-01-01

50

Toxins of a blue-green alga: similarity to saxitoxin.  

PubMed

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. PMID:5684499

Jackim, E; Gentile, J

1968-11-22

51

Blue-Green Algae and Rice.  

National Technical Information Service (NTIS)

Rising costs of the chemical fertilizers used to provide the combined nitrogen needed for rice production have prompted rice researchers to turn their attention to biological nitrogen sources such as blue-green (BGA). Although BGA produced nitrogen when i...

P. A. Roger S. A. Kulasooriya

1980-01-01

52

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

53

Use of fungicides to control blue-green algae on Bermuda grass putting-green surfaces  

Microsoft Academic Search

Cyanobacteria, commonly called blue-green algae, are a pest on Bermuda grass (Cynodon spp.) golf course putting-greens in Florida when excessive water is present. Four fungicide active ingredients: mancozeb, maneb, chlorothalonil and quaternary ammonium salts, were evaluated for control of this pest as preventive and curative treatments. All formulations of mancozeb, maneb and chlorothalonil were effective as preventive applications, but not

M. L. Elliott

1998-01-01

54

Oxygen Isotope Fractionation during Photosynthesis in a Blue-Green and a Green Alga 12  

PubMed Central

Oxygen isotope fractionation (18O/16O) at the natural abundance level has been measured during photosynthesis of a blue-green and a green alga. When sufficient attention is paid to removal of contaminating air O2 before and during the experiments, then the photosynthetic O2 evolved, as compared to the water O2, had an average difference of ?0.36% for a blue-green alga and ?0.80% for a green alga. These experiments suggest that there is no reason to invoke an inverse isotope effect in photosynthesis as part of the explanation for the 18O enrichment in atmospheric O2 relative to O2 in oceanic waters. In addition, in an indirect way, the experiments also support the argument that the bulk of O2 evolved during photosynthesis comes from water. A 10% contribution of O2 arising from CO2 would have been detectable in the present work.

Stevens, Catherine L. R.; Schultz, David; Van Baalen, Chase; Parker, Patrick L.

1975-01-01

55

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

PubMed

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

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

2011-04-27

56

Ribosomes from the blue-green alga Anabaena variabilis  

Microsoft Academic Search

Extracts from the blue-green alga Anabaena variabilis were prepared by ultrasonic disintegration or by extrusion through a French pressure cell; examination by sucrose density gradient centrifugation and analytical ultracentrifugation indicated the existence of a procaryotic (70S) ribosome. However both the ribosomes and their sub-units were found to be relatively unstable after isolation and examination in tris buffer pH 7.4 but

I. W. Craig; N. G. Carr

1968-01-01

57

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

58

Sustainability and cyanobacteria (blue-green algae): facts and challenges  

Microsoft Academic Search

Cyanobacteria (blue-green algae) are widely distributed Gram-negative oxygenic photosynthetic prokaryotes with a long evolutionary\\u000a history. They have potential applications such as nutrition (food supplements and fine chemicals), in agriculture (as biofertilizer\\u000a and in reclamation of saline USAR soils) and in wastewater treatment (production of exopolysaccharides and flocculants). In\\u000a addition, they also produce wide variety of chemicals not needed for their

Naveen K. Sharma; Sri Prakash Tiwari; Keshwanand Tripathi; Ashwani K. Rai

59

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

60

Unearthing the Molecular Phylodiversity of Desert Soil Green Algae (Chlorophyta)  

Microsoft Academic Search

Abstract.—Deserts are not usually considered biodiversity hotspots, but desert microbiotic crust communities exhibit a rich diversity of both eukaryotic and prokaryotic life forms. Like many communities dominated by microscopic organisms, they defy characterization by traditional species-counting approaches,to assessing biodiversity. Here we use exclusive molecular phylodiversity,(E )t oquantify the amount,of evolutionary,divergence,unique,to desert-dwelling green algae (Chlorophyta) in microbiotic crust communities.,Given a phylogenetic,tree

LOUISE A. LEWIS; PAUL O. LEWIS

2005-01-01

61

Cytoarchitecture of the desiccation-tolerant green alga Zygogonium ericetorum  

Microsoft Academic Search

In this study, the filamentous green alga Zygogonium ericetorum (Zygnematales, Chlorophyta), collected at its natural habitat in the high alps, was investigated by light, scanning, and\\u000a transmission electron microscopy. The field samples were separated into a moist fraction when wetted by splattering water\\u000a of a nearby spring or a desiccated one when visually dried out. Light microscopy demonstrated a purple

A. Holzinger; A. Tschaikner; D. Remias

2010-01-01

62

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

NASA Astrophysics Data System (ADS)

A universal design paradigm in biology is the use of hierarchies, which is evident in the structure of proteins, cells, tissues, and organisms, as well as outside the material realm in the design of signaling networks in complex organs such as the brain. A fascinating example of a biological structure is that of diatoms, a microscopic mineralized algae that is mainly composed of amorphous silica, which features a hierarchical structure that ranges from the nano- to the macroscale. Here, we use the porous structure found at submicron length scales in diatom algae as a basis to study a bioinspired nanoporous material implemented in crystalline silica. We consider the mechanical performance of two nanoscale levels of hierarchy, studying an array of thin-walled foil silica structures and a hierarchical arrangement of foil elements into a porous silica mesh structure. By comparing their elastic, plastic, and failure mechanisms under tensile deformation, we elucidate the impact of hierarchies and the wall width of constituting silica foils on the mechanical properties, by carrying out a series of large-scale molecular dynamics (MD) simulations with the first principles based reactive force field ReaxFF. We find that by controlling the wall width and by increasing the level of hierarchy of the nanostructure from a foil to a mesh, it is possible to significantly enhance the mechanical response of the material, creating a highly deformable, strong, and extremely tough material that can be stretched in excess of 100 pct strain, in stark contrast to the characteristic brittle performance of bulk silica. We find that concurrent mechanisms of shearing and crack arrest lead to an enhanced toughness and are enabled through the hierarchical assembly of foil elements into a mesh structure, which could not be achieved in foil structures alone. Our results demonstrate that including higher levels of hierarchy are beneficial in improving the mechanical properties and deformability of intrinsically brittle materials. The findings reported here provide insight into general material design approaches that may enable us to transform a brittle material such as silicon or silica into a ductile, yet strong and tough material, solely through alterations of its structural arrangement at the nanoscale.

Garcia, Andre P.; Sen, Dipanjan; Buehler, Markus J.

2011-12-01

63

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.

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

2011-01-01

64

Lysis of Blue-Green Algae by Myxobacter  

PubMed Central

Enrichment from local fishponds led to the isolation of a bacterium capable of lysing many species of unicellular and filamentous blue-green algae, as well as certain bacteria. The isolate is an aflagellate, motile rod which moves in a gliding, flexuous manner; the organism is capable of digesting starch and agar, but not cellulose and gelatin. Its deoxyribonucleic acid base pair composition (per cent guanine plus cytosine ?70) shows a close resemblance to that of the fruiting myxobacteria. Algae in lawns on agar plates were lysed rapidly by the myxobacter, but only limited and slow lysis occurred in liquid media, and no lysis took place when liquid cultures were shaken. No diffusible lytic factors would be demonstrated. Continuous observation of the lytic process under a phase-contrast microscope suggested that a close contact between the polar tip of the myxobacter and the alga is necessary for lysis. The lytic action is limited to the vegetative cells of the algae, whereas heterocysts are not affected. The gas vacuoles of the algal host are the only remnant visible after completion of digestion by the myxobacter. Images

Shilo, Miriam

1970-01-01

65

Equilibrium and kinetics studies of heavy metal ions biosorption on green algae waste biomass  

Microsoft Academic Search

The biosorption of Pb(II), Cd(II), and Co(II), respectively, from aqueous solution on green algae waste biomass was investigated. The green algae waste biomass was obtained from marine green algae after extraction of oil, and was used as low-cost biosorbent. Batch shaking experiments were performed to examine the effects of initial solution pH, contact time and temperature. The equilibrium biosorption data

Dumitru Bulgariu; Laura Bulgariu

66

Unearthing the molecular phylodiversity of desert soil green algae (Chlorophyta).  

PubMed

Deserts are not usually considered biodiversity hotspots, but desert microbiotic crust communities exhibit a rich diversity of both eukaryotic and prokaryotic life forms. Like many communities dominated by microscopic organisms, they defy characterization by traditional species-counting approaches to assessing biodiversity. Here we use exclusive molecular phylodiversity (E) to quantify the amount of evolutionary divergence unique to desert-dwelling green algae (Chlorophyta) in microbiotic crust communities. Given a phylogenetic tree with branch lengths expressed in units of expected substitutions per site, E is the total length of all tree segments representing exclusively desert lineages. Using MCMC to integrate over tree topologies and branch lengths provides 95% Bayesian credible intervals for phylodiversity measures. We found substantial exclusive molecular phylodiversity based on 18S rDNA data, showing that desert lineages are distantly related to their nearest aquatic relatives. Our results challenge conventional wisdom, which holds that there was a single origin of terrestrial green plants and that green algae are merely incidental visitors rather than indigenous components of desert communities. We identify examples of lineage diversification within deserts and at least 12 separate transitions from aquatic to terrestrial life apart from the most celebrated transition leading to the embryophyte land plants. [Bayesian phylogenetics; biodiversity; exclusive molecular phylodiversity; microbiotic crusts.]. PMID:16338765

Lewis, Louise A; Lewis, Paul O

2005-12-01

67

PCD and autophagy in the unicellular green alga Micrasterias denticulata  

PubMed Central

Programmed cell death (PCD) plays a central role in normal plant development and is also induced by various biotic and abiotic stress factors. In the unicellular freshwater green alga Micrasterias denticulata morphological and biochemical hallmarks such as the appearance of autophagosomes, increased production of ROS and degradation of genomic DNA into small fragments (“DNA laddering”) indicate PCD. Our data not only demonstrate that Micrasterias is capable of performing PCD under salt stress, but also that it is triggered by the ionic and not osmotic component of salinity. Additionally, results from the present and previous studies suggest that different inducers may lead to different cell death pathways in one and the same organism.

Affenzeller, Matthias Josef; Darehshouri, Anza; Andosch, Ancuela; Lutz, Cornelius; Lutz-Meindl, Ursula

2010-01-01

68

Coprecipitation of phosphate with calcite in the presence of photosynthesizing green algae  

Microsoft Academic Search

The results of phosphate coprecipitation on calcite, occurring in a solution of calcium bicarbonate, in the presence of photosynthesizing algae are presented. The precipitation experiments were carried out at 20°C in an illuminated culture apparatus with continuous recordings of pH and conductivity. The alga used in the experiment was the unicellular green alga Chlorococcum sp. The results are analysed using

A. M. Hartley; W. A. House; M. E. Callow; B. S. C. Leadbeater

1997-01-01

69

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

70

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

71

Solar-driven hydrogen production in green algae.  

PubMed

The twin problems of energy security and global warming make hydrogen an attractive alternative to traditional fossil fuels with its combustion resulting only in the release of water vapor. Biological hydrogen production represents a renewable source of the gas and can be performed by a diverse range of microorganisms from strict anaerobic bacteria to eukaryotic green algae. Compared to conventional methods for generating H(2), biological systems can operate at ambient temperatures and pressures without the need for rare metals and could potentially be coupled to a variety of biotechnological processes ranging from desalination and waste water treatment to pharmaceutical production. Photobiological hydrogen production by microalgae is particularly attractive as the main inputs for the process (water and solar energy) are plentiful. This chapter focuses on recent developments in solar-driven H(2) production in green algae with emphasis on the model organism Chlamydomonas reinhardtii. We review the current methods used to achieve sustained H(2) evolution and discuss possible approaches to improve H(2) yields, including the optimization of culturing conditions, reducing light-harvesting antennae and targeting auxiliary electron transport and fermentative pathways that compete with the hydrogenase for reductant. Finally, industrial scale-up is discussed in the context of photobioreactor design and the future prospects of the field are considered within the broader context of a biorefinery concept. PMID:21807246

Burgess, Steven J; Tamburic, Bojan; Zemichael, Fessehaye; Hellgardt, Klaus; Nixon, Peter J

2011-01-01

72

Distribution and relationships between selected chemical elements in green alga Enteromorpha sp. from the southern Baltic  

Microsoft Academic Search

The concentrations of heavy metals (Cd, Cu, Ni, Pb, Zn and Mn) and macroelements (K, Na, Ca and Mg) were determined in green alga Enteromorpha sp. from the coastal zone of the southern Baltic including Gulf of Gda?sk and Vistula Lagoon in 2000–2003. In order to estimate the degree of accumulation of each element by the green alga, concentration and

Rados?aw ?bikowski; Piotr Szefer; Adam Lata?a

2006-01-01

73

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

PubMed Central

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

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

1970-01-01

74

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

PubMed

Defined media consisting of inorganic salts and vitamin B(12) are described for the male and female filaments of the green alga, Oedogonium cardiacum. These media provide for a maximal growth rate and for the induction of oogonia and antheridia under the prescribed conditions. The maximal amounts of growth, based on dry weight measurements, compare favorably with other green algae. PMID:16657439

Hill, G J; Machlis, L

1970-08-01

75

The Nature and Distribution of Carotenoids in some Blue-Green Algae  

Microsoft Academic Search

SUMMARY : Seven blue-green algae, Anabaena cylindrica, A. variabilis, Coccochloris elabens, Cylindrospermum sp., Mastigocladus laminosus, Microcoleus vaginatus and Nostoc sp., synthesize the same three major carotenoids : ,&carotene, echinenone and myxoxanthophyll; zeaxanthin is present in small amounts. Lutein could not be detected. \\/3-Carotene represents between 30 and 60% of the total carotenoids present. The carotenoid distribution in blue-green algae and

T. W. Goodwin

1957-01-01

76

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

Microsoft Academic Search

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

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

2010-01-01

77

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

Microsoft Academic Search

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

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

1964-01-01

78

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

79

The measurement and significance of ATP pools in filamentous blue-green algae  

Microsoft Academic Search

A modified luciferin-luciferase assay has been developed for measuring ATP pools in filamentous blue-green algae. The assay, which should be applicable to studies on algae in general, is simple, reliable, inexpensive, sensitive at the pmole level and can be used in any laboratory with a suitable liquid scintillation counter. Studies using the two blue-green algae, Anabaena cylindrica and Anabaenopsis circularis

P. J. Bottomley; W. D. P. Stewart

1976-01-01

80

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

81

Temporal variance in lake communities: blue-green algae and the trophic cascade  

Microsoft Academic Search

Two examples, blue-green algal blooms and the fish-driven trophic cascade, illustrate important consequences of time scale dependency in lakes. Blue-green algae and fish populations are notably variable components of lake communities. The timing of colonization of the water column by blue-green algae, relative to population oscillations of grazers and other algal groups, determines the magnitude of subsequent blooms. Variability in

Stephen R. Carpenter

1989-01-01

82

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

83

Spectrin-like proteins in green algae (Desmidiaceae).  

PubMed

Immunochemical detection of actin as well as spectrin-like proteins have been carried out in the green algae Micrasterias denticulata, Closterium lunula, and Euastrum oblongum. In these algae, actin is detected on Western blots at 43 kDa with antibodies to actin from higher plant and animal origin. By use of antibodies to human and chicken erythrocyte spectrin a cross-reactivity with desmid proteins is found at about the molecular mass of 220 kDa, where also human erythrocyte spectrin is detected. Additional bands are present at 120 kDa and 70 kDa, which are probably breakdown products. An antibody against chicken alpha-actinin, a small protein of the spectrin superfamily, recognizes bands at 90 kDa, where it is expected, and 70 kDa, probably the same breakdown product as mentioned for spectrin. Isoelectric focusing provides staining at pI 4.6 with antibodies against spectrin. Immunogold labelling of spectrin and alpha-actinin antigens on high-pressure frozen, freeze-substituted Micrasterias denticulata cells with the same antibodies exhibits staining, especially at membranes of different populations of secretory vesicles, at dictyosomes, and the plasma membrane. However, no clear correlation to the growth pattern of the cell could be observed. Taken together, our results demonstrate the presence of spectrin-like proteins in desmid cells which are probably functional in exocytosis. PMID:10579899

Holzinger, A; De Ruijter, N; Emons, A M; Lütz-Meindl, U

1999-01-01

84

Amidic and acetonic cryoprotectants improve cryopreservation of volvocine green algae.  

PubMed

A number of volvocalean green algae species were subjected to a two-step cryopreservation protocol with various cryoprotectants. Potential cryoprotectants were methanol (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methylformamide, and hydroxyacetone (HA). We confirmed prior reports that MeOH was effective for cryopreserving Chlamydomonas, but did not work well for larger volvocaleans such as Volvox. In contrast, DMF and HA were effective for both unicellular and multicellular representatives. When we used a cold-inducible transposon to probe Southern blots of Volvox DNA samples taken before and after storage for one month in LN, we could detect no differences, indicating that the genome had remained relatively stable and that the transposon had not been induced by the cryopreservation procedure. We believe these methods will facilitate long-term storage of several volvocine algal species, including Volvox strains harboring transposon-induced mutations of developmental interest. PMID:22825787

Nakazawa, A; Nishii, I

85

Immunocytochemical localization of nitrite reductase in green algae.  

PubMed

The distribution of nitrite reductase (EC 1.7.7.1) in the green algae Chlamydomonas reinhardtii, Monoraphidium braunii, Chlorella fusca, and Scenedesmus obliquus was studied by immunoelectron microscopy. The labeling of ultrathin cryosections was performed with anti-nitrite reductase antibodies followed by gold-labeled goat anti-rabbit antibodies. In C. reinhardtii sections, gold label was mainly associated with the pyrenoid, tonoplast, and plasmalemma. Significant labeling was also detected in the thylakoid region. In all other organisms, label density was lower but distributed in the same locations, except that the plasmalemma of S. obliquus was not significantly labeled. From estimates of the relative volume of different cell regions, we found that approximately 80% of the total enzyme is located in the chloroplastic region (thylakoids plus pyrenoid) of C. reinhardtii, M. braunii, and C. fusca, and 97% in the case of S. obliquus. PMID:16668245

López-Ruiz, A; Verbelen, J P; Bocanegra, J A; Diez, J

1991-07-01

86

Immunocytochemical Localization of Nitrite Reductase in Green Algae 1  

PubMed Central

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

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

1991-01-01

87

PCD and autophagy in the unicellular green alga Micrasterias denticulata.  

PubMed

Programmed cell death (PCD) plays a central role in normal plant development and is also induced by various biotic and abiotic stress factors. In the unicellular freshwater green alga Micrasterias denticulata morphological and biochemical hallmarks such as the appearance of autophagosomes, increased production of ROS and degradation of genomic DNA into small fragments ("DNA laddering") indicate PCD. Our data not only demonstrate that Micrasterias is capable of performing PCD under salt stress, but also that it is triggered by the ionic and not osmotic component of salinity. Additionally, results from the present and previous studies suggest that different inducers may lead to different cell death pathways in one and the same organism. PMID:19430197

Affenzeller, Matthias Josef; Darehshouri, Anza; Andosch, Ancuela; Lütz, Cornelius; Lütz-Meindl, Ursula

2009-08-20

88

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

Microsoft Academic Search

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

RUTH E. HOLLAND; LARRY W. CLAFLIN

1975-01-01

89

The effects of nitric oxide in settlement and adhesion of zoospores of the green alga Ulva.  

PubMed

Previous studies have shown that elevated nitric oxide (NO) reduces adhesion in diatom, bacterial and animal cells. This article reports experiments designed to investigate whether elevated NO reduces the adhesion of zoospores of the green alga Ulva, an important fouling species. Surface-normalised values of NO were measured using the fluorescent indicator DAF-FM DA and parallel hydrodynamic measurements of adhesion strength were made. Elevated levels of NO caused by the addition of the exogenous NO donor SNAP reduced spore settlement by 20% and resulted in lower adhesion strength. Addition of the NO scavenger cPTIO abolished the effects of SNAP on adhesion. The strength of attachment and NO production by spores in response to four coatings (Silastic T2; Intersleek 700; Intersleek 900 and polyurethane) shows that reduced adhesion is correlated with an increase in NO production. It is proposed that in spores of Ulva, NO is used as an intracellular signalling molecule to detect how conducive a surface is for settlement and adhesion. The effect of NO on the adhesion of a range of organisms suggests that NO-releasing coatings could have the potential to control fouling. PMID:19927239

Thompson, Stephanie E M; Callow, Maureen E; Callow, James A

2010-01-01

90

Channelrhodopsin-1: a light-gated proton channel in green algae.  

PubMed

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 Xenopus laevis oocytes in the presence of all-trans retinal produces a light-gated conductance that shows characteristics of a channel selectively permeable for protons. We suggest that Channelrhodopsins are involved in phototaxis of green algae. PMID:12089443

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

2002-06-28

91

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

PubMed Central

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

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

2012-01-01

92

Acid Mine Drainage Treatment Utilizing Blue-Green Algae.  

National Technical Information Service (NTIS)

Preliminary studies suggested that freshwater algae accumulate relatively large concentrations of iron and manganese from AMD. A wetland was designed and constructed to treat a discharge from an abandoned deep mine to examine algae's ability to accumulate...

D. A. Kepler

1989-01-01

93

Systematics of the marine microfilamentous green algae Uronema curvatum and Urospora microscopica (Chlorophyta)  

Microsoft Academic Search

The microfilamentous green alga Uronema curvatum is widely distributed along the western and eastern coasts of the north Atlantic Ocean where it typically grows on crustose red algae and on haptera of kelps in subtidal habitats. The placement of this marine species in a genus of freshwater Chlorophyceae had been questioned. Molecular phylogenetic analysis of nuclear-encoded small and large subunit

Frederik Leliaert; Jan Rueness; Christian Boedeker; Christine A. Maggs; Ellen Cocquyt; Heroen Verbruggen; Olivier De Clerck

2009-01-01

94

Water Purification and Recovery of Fertilizer Materials by Blue Green Algae (Cyanobacteria). Final Report.  

National Technical Information Service (NTIS)

The object of this research project was to compare the water purification and recovery of fertilizer materials by blue green algae (Cyanobacteria) under thermal and non-thermal or ambient conditions. The thermal tests were conducted in a solar algae growt...

J. Bender

1983-01-01

95

Water purification and recovery of fertilizer materials by blue green algae (Cyanobacteria). Final report  

Microsoft Academic Search

The object of this research project was to compare the water purification and recovery of fertilizer materials by blue green algae (Cyanobacteria) under thermal and non-thermal or ambient conditions. The thermal tests were conducted in a solar algae growth tank, in which a solar heat exchanger provided thermal conditions of 60 C during daytime hours. 6 figures, 1 table.

2008-01-01

96

Selective production of glutamate by an immobilized marine blue-green alga, Synechococcus sp  

Microsoft Academic Search

Among 200 strains of marine bluegreen algae isolated from the coastal areas of Japan, the marine blue-green alga Synechococcus sp. NKBG 040607 excreted glutamate at the highest rate, 82.6% of total amino acids production being glutamate. Synechococcus sp. NKBG 40607 was immobilized in calcium alginate gel. Glutamate production by immobilized cells was double that of native cells. Maximal glutamate production

Tadashi Matsunaga; Noriyuki Nakamura; Naoko Tsuzaki; Hiroyuki Takeda

1988-01-01

97

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

98

Novel Extrachromosomal DNA from Giant-celled Green Algae: Characterization and Utilization.  

National Technical Information Service (NTIS)

The objectives of this document is to determine the fundamental characteristics and utility of novel extrachromosomal DNA in coenocytic/ multinucleate marine green algae. This includes determining: 1) its complexity and what genes it encodes, 2) whether i...

J. W. LA Claire

1998-01-01

99

PLANKTONIC BLUE-GREEN ALGAE: Growth and Odor-Production Studies  

Microsoft Academic Search

Planktonic blue-green algae are aquatic microorganisms that form on or near the bottom of reservoirs. This article is concerned with nurient and biological influences on algal growth and its control by water-utility facilities.

J. K. Silvey; D. E. Henley; J. T. Wyatt

1972-01-01

100

Citric Acid Enhancement of Copper Sulfate Toxicity to Blue-Green Algae and Other Nuisance Organisms.  

National Technical Information Service (NTIS)

Copper toxicity tests were carried out using two species of blue-green algae, Aphanizomenon flos-aquae and Microcystis aeruginosa. Copper concentrations of 300 micrograms/liter or higher inhibited the growth of Aphanizomenon. The addition of 600 microgram...

M. S. Stern D. H. Stern L. L. Ray

1978-01-01

101

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

National Technical Information Service (NTIS)

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

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

1981-01-01

102

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

103

Purification of the blue-green pigment “marennine” from the marine tychopelagic diatom Haslea ostrearia (Gaillon\\/Bory) Simonsen  

Microsoft Academic Search

The diatom Haslea ostrearia that lives in oyster ponds has the distinctive feature of synthesizing “marennine”, a blue-green pigment of which the chemical nature still remains unknown. This pigment is responsible for the greening of oyster gills. Here, we report a new method for extraction and purification of intracellular (accumulated in the apex of the cell) and extracellular (released into

Jean-Bernard Pouvreau; Michèle Morançais; Guillaume Massé; Philippe Rosa; Jean-Michel Robert; Joël Fleurence; Pierre Pondaven

2006-01-01

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

2012-05-08

105

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

106

Removal of Methylene Blue from aqueous solution by marine green alga Ulva lactuca  

Microsoft Academic Search

Biosorption of colours is an important technology for treatment of different types of industrial wastewaters containing dyes. The objective of this study was to convert green alga Ulva lactuca to dye adsorbents for wastewater treatment. The importance of commonly available green alga Ulva lactuca was investigated as viable biomaterials for the biological treatment of synthetic basic blue 9 (5-ch1oro-N,N,N ,N

A. El Sikaily; A. Khaled; A. El Nemr; O. Abdelwahab

2006-01-01

107

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

108

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

Microsoft Academic Search

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

Samy Boussiba; Amos E. Richmond

1979-01-01

109

Acclimation of green algae to sulfur deficiency: underlying mechanisms and application for hydrogen production  

Microsoft Academic Search

Hydrogen is definitely one of the most acceptable fuels in the future. Some photosynthetic microorganisms, such as green algae\\u000a and cyanobacteria, can produce hydrogen gas from water by using solar energy. In green algae, hydrogen evolution is coupled\\u000a to the photosynthetic electron transport in thylakoid membranes via reaction catalyzed by the specific enzyme, (FeFe)-hydrogenase.\\u000a However, this enzyme is highly sensitive

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

2011-01-01

110

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

PubMed

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

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

2001-06-01

111

Studies of marine epiphytic algae, Calvi, Corsica. II. Seasonal variations in the populations of epiphytic blue-green algae in three harbours with different pollution loads  

Microsoft Academic Search

Variations in the populations of blue-green algae epiphytic on Cladophora prolifera were studied quantitatively for a year in three harbours of contrasting water quality in the area of Calvi (Corsica). The development of blue-green algae was maximal in the summer and minimal in winter and spring, with some differences between the harbours. Density of filaments or colonies varied between 15

A. Wilmotte; V. Demoulin

1988-01-01

112

Intracellular ?-Carbonic Anhydrase of the Unicellular Green Alga Coccomyxa1  

PubMed Central

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

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

1998-01-01

113

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.

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

2012-01-01

114

Phylogenetic and molecular analysis of hydrogen-producing green algae.  

PubMed

A select set of microalgae are reported to be able to catalyse photobiological H(2) production from water. Based on the model organism Chlamydomonas reinhardtii, a method was developed for the screening of naturally occurring H(2)-producing microalgae. By purging algal cultures with N(2) in the dark and subsequent illumination, it is possible to rapidly induce photobiological H(2) 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 H(2). Using this system, five algal isolates capable of H(2) 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 H(2) production. H(2)-producing algal species were seen to be dispersed amongst most clades, indicating an H(2)-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

2009-04-02

115

Green algae as a structural element of phytoperiphyton communities in streams of NW Russia  

Microsoft Academic Search

Observations were made on the development and distribution of phytoperiphyton communities in 66 lake-river systems in NW Russia\\u000a from Lake Ladoga to the Barents Sea. In total, 130 genera and 648 species were identified from different substrates, belonging\\u000a to Cyanophyta (19.1%), Bacillariophyta (59.6%), Chlorophyta (18.7%), and algae from other orders (2.6%). In all streams diatoms dominated by species richness, but

Sergey F. Komulaynen

2008-01-01

116

Formation of Carbon Monoxide and Bile Pigment in Red and Blue-Green Algae 1  

PubMed Central

Five blue-green and one red algal species produced carbon monoxide during photosynthetic growth. The blue-green algae synthesized CO and phycocyanobilin in equimolar quantities at identical rates. The red alga, Porphyridium cruentum, incorporated ?-aminolevulinic acid-5-14C into phycoerythrobilin and CO. The ratio of the specific radioactivity of phycoerythrobilin to that of CO, and the kinetics and stoichiometry of phycocyanobilin and CO formation suggest that linear tetrapyrroles in plants are derived by the porphyrin pathway via the intermediate formation of heme. The similarity between bile pigment production in algae and in mammalian systems is discussed.

Troxler, Robert F.; Dokos, Joy M.

1973-01-01

117

Algae as Protein Factories: Expression of a Human Antibody and the Respective Antigen in the Diatom Phaeodactylum tricornutum  

PubMed Central

Microalgae are thought to offer great potential as expression system for various industrial, therapeutic and diagnostic recombinant proteins as they combine high growth rates with all benefits of eukaryotic expression systems. Moreover, microalgae exhibit a phototrophic lifestyle like land plants, hence protein expression is fuelled by photosynthesis, which is CO2-neutral and involves only low production costs. So far, however, research on algal bioreactors for recombinant protein expression is very rare calling for further investigations in this highly promising field. In this study, we present data on the expression of a monoclonal human IgG antibody against the Hepatitis B surface protein and the respective antigen in the diatom Phaeodactylum tricornutum. Antibodies are fully-assembled and functional and accumulate to 8.7% of total soluble protein, which complies with 21 mg antibody per gram algal dry weight. The Hepatitis B surface protein is functional as well and is recognized by algae-produced and commercial antibodies.

Hempel, Franziska; Lau, Julia; Klingl, Andreas; Maier, Uwe G.

2011-01-01

118

The green alga Dicytosphaeria ocellata and its organic extracts alter natural bacterial biofilm communities.  

PubMed

Surfaces immersed in the marine environment are under intense fouling pressure by a number of invertebrates and algae. The regulation of this fouling can often be attributed to the bacterial biofilm that quickly develops on the surface of any available substratum in the ocean. The bacterial community composition on the surface of the green alga Dictyosphaeria ocellata was investigated and compared to those found on two other green algae, Batophora oerstedii and Cladophoropsis macromeres, and on a reference surface from three sites along the Florida Keys. Although the bacterial community composition of D. ocellata was not consistent across the sites, it was significantly different from the other algae and the reference surface at two of the three sites tested. Methanol extracts of D. ocellata significantly affected the abundance of bacteria and composition of the bacterial community on Phytagel™ plates when compared to solvent controls, suggesting that the alga regulates the bacterial community by producing active metabolites. PMID:21512919

Sneed, Jennifer M; Pohnert, Georg

2011-04-01

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

Toxicity of propargylic alcohols on green alga--Pseudokirchneriella subcapitata.  

PubMed

The present study evaluates the toxicity of 34 propargylic alcohols, including primary, primary homo-, secondary, and tertiary alcohols, based on their effects on phytoplankton. A closed-system algal toxicity test was applied because the closed-system technique presents more realistic concentration-response relationships for the above compounds than the conventional batch tests. The green alga, Pseudokirchneriella subcapitata, was the test organism and final yield and growth rate were chosen as the test endpoints. Among all the propargylic alcohols tested, 1-pentyn-3-ol is the most toxic compound with its EC50 equal to 0.50 mg L(-1), which can be classified as a "R50" compound (very toxic to aquatic organisms, EC50/LC50 < 1 mg L(-1)), following the current practice for classification of chemicals in the European Union (EU). There are several other compounds including 2-decyn-1-ol, 3-decyn-1-ol, 1-hexyn-3-ol, 3-butyn-2-ol, and 3-hexyne-2,5-diol, which deserve more attention for their possible adverse impact on the aquatic environment, because these alcohols can be classified as "R51" compounds (toxic to aquatic organisms, EC50/LC50 between 1 and 10 mg L(-1)). Compared to the base-line toxicity relationship (narcosis QSAR) derived previously, tertiary propargylic alcohols can be identified as nonpolar narcotic chemicals, while secondary alcohols and primary alcohols with low molecular weight generally exhibit obvious excess toxicity in relation to the base-line toxicity. Finally, quantitative structure-activity relationships were established for deriving a preliminary estimation of the toxicity of other propargylic alcohols. PMID:22105539

Chen, Chung Yuan; Kuo, Kwan-Liang; Fan, Je-Wei

2011-11-21

122

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

2010-02-20

123

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

124

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

Microsoft Academic Search

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

Jocelyne Trémouillaux-Guiller; Volker A. R. Huss

2007-01-01

125

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

Microsoft Academic Search

The herbicide fluroxypyr is widely used for controlling weeds and insects but intensive use of fluroxypyr has resulted in\\u000a its widespread contamination in soils and aquatic ecosystems. To evaluate the eco-toxicity of fluroxypyr to green algae, bioaccumulation\\u000a and degradation of fluroxypyr in Chlamydomonas reinhardtii, a model unicellular alga, along with its biological adaptation to fluroxypyr toxicity were investigated. The microalgae

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

2011-01-01

126

Fate of substituted benzoates in the freshwater green alga, Chlamydomonas reinhardtii 11-32b  

Microsoft Academic Search

The removal of chlorinated, nitrated, and sulfonated benzoic acids in cultures of the unicellular green alga, Chlamydomonas reinhardtii 11-32b, was investigated, and the metabolic fate of a model compound, 4-chloro-3,5-dinitrobenzoic acid, was determined. The freshwater alga was able to remove a wide variety of benzoic compounds from the incubation medium. Chlamydomonas discriminated very specifically between the benzoic acids, indicated by

Anne Gutenkauf; Andreas Düker; Heinrich P. Fock

1998-01-01

127

The biosynthetic pathway of carotenoids in the astaxanthin-producing green alga Chlorella zofingiensis  

Microsoft Academic Search

The carotenoid composition of the astaxanthin-producing green alga Chlorella zofingiensis was investigated using high-performance liquid chromatography. Astaxanthin, adonixanthin, and zeaxanthin are the major carotenoids\\u000a in this alga. The pigment pattern was characterized during the accumulation period, and in response to diphenylamine (DPA),\\u000a an inhibitor of carotenoid biosynthesis. An increase in zeaxanthin followed by a decrease in xanthophyll was seen after

Yan Wang; Tao Chen

2008-01-01

128

Preliminary characterisation of the blue-green pigment “marennine” from the marine tychopelagic diatom Haslea ostrearia (Gaillon\\/Bory) Simonsen  

Microsoft Academic Search

Haslea ostrearia is a common marine tychopelagic diatom which has the particularity of synthesizing a blue-green hydrosoluble pigment called “marennine”. This pigment, when released into the external medium, is known to be responsible for the colour of oyster gills. Here we present results for main biophysical and biochemical characteristics of pure intra- and extracellular marennine. Tests for chemical determination show

Jean-Bernard Pouvreau; Michèle Morançais; Fabrice Fleury; Philippe Rosa; Laurent Thion; Blanche Cahingt; Franck Zal; Joël Fleurence; Pierre Pondaven

2006-01-01

129

Equilibrium and kinetics studies of heavy metal ions biosorption on green algae waste biomass.  

PubMed

The biosorption of Pb(II), Cd(II), and Co(II), respectively, from aqueous solution on green algae waste biomass was investigated. The green algae waste biomass was obtained from marine green algae after extraction of oil, and was used as low-cost biosorbent. Batch shaking experiments were performed to examine the effects of initial solution pH, contact time and temperature. The equilibrium biosorption data were analyzed using two isotherm models (Langmuir and Freundlich) and two kinetics models (pseudo-first order and pseudo-second order). The results indicate that Langmuir model provide best correlation of experimental data, and the pseudo-second order kinetic equation could best describe the biosorption kinetics of considered heavy metals. PMID:22055103

Bulgariu, Dumitru; Bulgariu, Laura

2011-10-19

130

Extraction and quantitative analysis of the blue-green pigment “marennine” synthesized by the diatom Haslea ostrearia  

Microsoft Academic Search

This study reports further information on “mareninne,” awater-soluble blue-green pigment synthesized by the diatom Hasleaostrearia, which is essential to the greening of maturing oysters inFrench production areas. The extraction process is reported, as well aspreliminary characterization of a partially purified marennine extract,including quantitative spectrophotometric analysis of intracellular pigment. Amean specific extinction coefficient, E 1%1cm = 17.2 at 669 nm, is

Jean-Michel Robert; Michèle Morançais; Elisabeth Pradier; Jean-Luc Mouget; Gérard Tremblin

2002-01-01

131

Chloroplast-mitochondria cross-talk in diatoms.  

PubMed

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

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

2012-01-20

132

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

133

Nitrate Reductase of Green Algae Is Located in the Pyrenoid 1  

PubMed Central

Antibodies against nitrate reductase from Monoraphidium braunii have been used to determine the antigenic relationships of nitrate reductases from different green algae. Nitrate reductases from Chlamydomonas reinhardii, Chlorella fusca, Dunaliella salina, and Scenedesmus obliquus, were inhibited by, and cross-reacted with, antibodies raised against the enzyme from Monoraphidium braunii. These antibodies were also used to determine, by immunoelectron microscopy, the intracellular location of nitrate reductase in the aforementioned green algae. In all cases, the enzyme was specifically located in the pyrenoid. Images Fig. 4 Fig. 5 Fig. 1 Fig. 3 Fig. 6

Lopez-Ruiz, Antonio; Verbelen, Jean Pierre; Roldan, Jose Manuel; Diez, Jesus

1985-01-01

134

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...

135

Impact of Toxic Clones of Blue-Green Algae on Water Quality as Related to Aquatic Animals.  

National Technical Information Service (NTIS)

The literature indicates that toxic blooms of blue-green algae occur widely. Several species of blue-green algae have been associated with these toxic blooms in North America, but the most commonly occuring toxic species are Anabaena flos-aquae, Microcyst...

J. J. Sasner M. Ikawa P. J. Sawyer

1977-01-01

136

Lower pH Limit for the Existence of Blue-Green Algae: Evolutionary and Ecological Implications  

Microsoft Academic Search

Observations on a wide variety of acidic environments, both natural and man-made, reveal that blue-green algae (Cyanophyta) are completely absent from habitats in which the pH is less than 4 or 5, whereas eukaryotic algae flourish. By using enrichment cultures with inocula from habitats of various pH values, the absence of blue-green algae at low pH was confirmed.

Thomas D. Brock

1973-01-01

137

The Photoreceptor Current of the Green Alga Chlamydomonas  

Microsoft Academic Search

The unicellular alga Chlamydomonas possesses a visual system which guides it to places that are optimal for photosynthetic growth. The rhodopsin, serving as the photoreceptor, conveys light information into a cellular signal. This signal is transmitted via several electrical steps to the flagella, where it modulates the flagellar beating pattern. The first detectable electrical process is the photoreceptor current, which

Hartmann Harz; Christina Nonnengasser; Peter Hegemann

1992-01-01

138

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

139

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

PubMed

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

Lüttge, U; Büdel, B

2010-05-01

140

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

141

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

2013-08-22

142

Hydrogen production by a thermophilic blue-green alga Mastigocladus laminosus  

NASA Astrophysics Data System (ADS)

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

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

143

Parameters affecting the growth and hydrogen production of the green alga Chlamydomonas reinhardtii  

Microsoft Academic Search

The green alga Chlamydomonas reinhardtii has the ability to photosynthetically produce molecular hydrogen (H2) under anaerobic conditions. It offers a biological route to renewable H2 production from sunlight and water. Algal growth and H2 production kinetics must be understood in order to determine appropriate system parameters and develop photobioreactors. Algal biomass should be grown efficiently and economically to attain the

Bojan Tamburic; Fessehaye W. Zemichael; Geoffrey C. Maitland; Klaus Hellgardt

2011-01-01

144

The Production of Extracellular Nitrogenous Substances by a Blue-Green Alga  

Microsoft Academic Search

A study has been made of the nature and origin of the organic nitrogenous products to be found in filtrates from cultures of the nitrogen-fixing blue-green alga Anabaena cylindrica Lemm. The total amount of combined nitrogen liberated in extracellular form is relatively greatest in young cultures. At this stage the amounts produced have not been found to be affected appreciably

G. E. Fogg

1952-01-01

145

Observations on the fine structure of spermatozoids and vegetative cells of the green alga Golenkinia  

Microsoft Academic Search

Spermatozoids and vegetative cells of the green alga Golenkinia minutissima Iyengar et Balakrishnan have been examined by light and electron microscopy. The biflagellate spermatozoids are of a somewhat specialised type, elongated with the nucleus attached to the flagellar bases, and containing a reduced chloroplast without pyrenoid or eyespot. The flagellar apparatus and root system has been examined in detail and

Øjvind Moestrup

1972-01-01

146

Effects of UV irradiation on cell development and ultrastructure of the green alga Micrasterias  

Microsoft Academic Search

The unicellular freshwater green alga Micrasterias denticulata growing in small acid bog ponds at different altitudes has been subjected to different UV conditions experimentally produced in a sun simulator in the presence of white light. The results show that the cells are resistant to UV cut-off wavelengths down to 284 nm even when exposed during the most sensitive stage of

Ursula Meindl; Cornelius Lütz

1996-01-01

147

PHYLOGENY OF THE CONJUGATING GREEN ALGAE (ZYGNEMOPHYCEAE) BASED ON rbc L SEQUENCES  

Microsoft Academic Search

Sequences of the gene encoding the large subunit of RUBISCO ( rbc L) for 30 genera in the six currently recognized families of conjugating green algae (Des- midiaceae, Gonatozygaceae, Mesotaeniaceae, Peni- aceae, and Zygnemataceae) were analyzed using maxi- mum parsimony and maximum likelihood; bootstrap replications were performed as a measure of support for clades. Other Charophyceae sensu Mattox and Stewart

Richard M. McCourt; Kenneth G. Karol; Jeremy Bell; Kathleen M. Helm-Bychowski; Anna Grajewska; Martin F. Wojciechowski; Robert W. Hoshaw

2000-01-01

148

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

149

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

Microsoft Academic Search

Cell division in vegetative filaments of the green alga Oedogonium cardiacum is presented as an experimental system. We report on how we have used this system to study the effects of isopropyl N-phenylcarbamat e (IPC) on the mitotic apparatus and on the phycoplast, a planar array of cytokinetic microtubules. Polymerization of microtubules was prevented when filaments, synchronized by a light\\/dark

RONALD A. COSS; JEREMY D. PICKETT-HEAPS

150

The kinetochore fiber structure in the acentric spindles of the green alga Oedogonium  

Microsoft Academic Search

Summary The microtubule (MT) arrangement in three kinetochore fibers in the acentric spindles of the green algaOedogonium cardiacum were reconstructed from serial sections of prometaphase and metaphase cells. The majority of the MTs attached to the kinetochore (kMTs) are relatively short, extending less than a third of the distance to the putative spindle pole region, and none extended the full

M. J. Schibler; J. D. Pickett-Heaps

1987-01-01

151

Microelement composition of the green alga Ulva fenestrata from Peter the Great Bay, Sea of Japan  

Microsoft Academic Search

Concentrations of heavy metals Fe, Mn, Cu, Zn, Pb, Cd, and Ni were determined in the thalluses of the green alga Ulva fenestrata sampled from different locations in Peter the Great Bay (Sea of Japan). According to the metal concentrations in Ulva, the degree of pollution of the surveyed areas in Peter the Great Bay decreases in the following series:

S. I. Kozhenkova; E. N. Chernova; V. M. Shulkin

2006-01-01

152

Identification of a copper-sensitive ascorbate peroxidase in the unicellular green alga Selenastrum capricornutum  

Microsoft Academic Search

Extracts from the unicellular green alga Selenastrum capricornutum exhibit high superoxide dismutase activity, but only traces of catalase activity. The excess hydrogen peroxide (HO) generated by the superoxide dismutase in S. capricornutum may be degraded by a unique peroxidase. This peroxidase has a high specificity for ascorbate as its electron donor. The enzyme has an optimum pH at 8, is

Kathleen R. Sauser; J. K. Liu; Tit-Yee Wong

1997-01-01

153

Influence of Blue-Green Algae on Survival of Legionella pneumophila in Aerosols.  

National Technical Information Service (NTIS)

The fluid in which blue-green algae (Fischerella sp.) had been grown (algal extract) was investigated for its effect on aerosols of Legionella pneumophila. The bacteria were significantly more stable when suspended in algal extract than in the tryptose-sa...

R. F. Berendt

1980-01-01

154

Calcium Oxalate Crystals in the Aragonite-Producing Green Alga Penicillus and Related Genera  

Microsoft Academic Search

Calcium oxalate crystals occur in the marine green algae Penicillus, Rhipocephalus, and Udotea, known as producers of sedimentary aragonite needles. In contrast to the externally deposited aragonite crystals which are generally < 15 micrometers long, the oxalate crystals are larger (up to 150 micrometers) and are located in the vacuolar system of the plant. No calcium oxalate was found in

E. Imre Friedmann; William C. Roth; James B. Turner; Ronald S. McEwen

1972-01-01

155

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

156

Vital staining permits isolation of calcium vesicles from the green alga Mougeotia  

Microsoft Academic Search

The calcium vesicles of the green alga Mougeotia (G. Wagner and R. Rossbacher, 1980, Planta 149, 298–305) were isolated for characterization in vitro by fractionation of algal homogenate on sucrose density gradients. A new technique, based on vital staining by neutral red or rhodamine B, permitted isolation. Minimum dye binding to the calcium vesicles prevented desintegration, and for isolation a

Franz Grolig; Gottfried Wagner

1987-01-01

157

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

Microsoft Academic Search

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

B. Teyssèdre

2007-01-01

158

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

159

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

160

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

SciTech Connect

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

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

1987-06-01

161

A convenient method to maintain unicellular green algae for long times as standing liquid cultures  

Microsoft Academic Search

A simple procedure is described to maintain unicellular green algae as slow growing standing liquid cultures for relatively long times. With this method the cultures of Chlorella pyrenoidosa, Chlorella vulgaris, Selenastrum capricornutum, Scenedesmus subspicatus, which are generally used for ecotoxicity testing were maintained viable and stable for more than 12 months in dim light at relatively low temperatures without shaking.

Khursheed A. Malik

1995-01-01

162

Effects of the parasiticide ivermectin on the cladoceran Daphnia magna and the green alga Pseudokirchneriella subcapitata  

Microsoft Academic Search

Although widely used for the treatment of endo- and ectoparasites in livestock and pets, very few data on chronic effects on aquatic organisms are available for the parasiticide ivermectin. In the present study, toxicity of ivermectin to two freshwater organisms, the cladoceran Daphnia magna and the green alga Pseudokirchneriella subcapitata was investigated. For D. magna, a mean LC50 48h of

Jeanne Garric; Bernard Vollat; Karen Duis; Alexandre Péry; Thomas Junker; Maria Ramil; Guido Fink; Thomas A. Ternes

2007-01-01

163

Colony development and physiological characterization of the edible blue-green alga, Nostoc sphaeroides (Nostocaceae, Cyanophyta)  

Microsoft Academic Search

The edible blue-green alga, Nostoc sphaeroides Kützing, is able to form microcolonies and spherical macrocolonies. It has been used as a potent herbal medicine and dietary supplement for centuries because of its nutraceutical and pharmacological benefits. However, limited information is available on the development of the spherical macrocolonies and the environmental factors that affect their structure. This report described the

Zhongyang Deng; Qiang Hu; Fan Lu; Guoxiang Liu; Zhengyu Hu

2008-01-01

164

The Photoassimilation of Organic Compounds by Autotrophic Blue-green Algae  

Microsoft Academic Search

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

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

1967-01-01

165

Calcium-dependent protein kinase in the green alga Chara  

Microsoft Academic Search

Cytoplasmic streaming in the characean algae is inhibited by micromolar rises in the level of cytosolic free Ca2+, but both the mechanism of action and the molecular components involved in this process are unknown. We have used monoclonal antibodies against soybean Ca2+-dependent protein kinase (CDPK), a kinase that is activated by micromolar Ca2+ and co-localizes with actin filaments in higher-plant

David W. McCurdy; Alice C. Harmon

1992-01-01

166

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

PubMed

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

Grauvogel, Carina; Petersen, Jörn

2007-03-15

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

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

Microsoft Academic Search

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

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

2008-01-01

169

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

PubMed

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

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

2008-09-24

170

Application of a chemically modified green macro alga as a biosorbent for phenol removal.  

PubMed

Phenol and substituted phenols are toxic organic pollutants present in tannery waste streams. Environmental legislation defines the maximum discharge limit to be 5-50 ppm of total phenols in sewers. Thus the efforts to develop new efficient methods to remove phenolic compounds from wastewater are of primary concern. The present work aims at the use of a modified green macro alga (Caulerpa scalpelliformis) as a biosorbent for the removal of phenolic compounds from the post-tanning sectional stream. The effects of initial phenol concentration, contact time, temperature and initial pH of the solution on the biosorption potential of macro algal biomass have been investigated. Biosorption of phenol by modified green macro algae is best described by the Langmuir adsorption isotherm model. Biosorption kinetics of phenol onto modified green macro algal biomass were best described by a pseudo second order model. The maximum uptake capacity was found to be 20 mg of phenol per gram of green macro algae. A Boyd plot confirmed the external mass transfer as the slowest step involved in the biosorption process. The average effective diffusion coefficient was found to be 1.44 x 10(-9) cm(2)/s. Thermodynamic studies confirmed the biosorption process to be exothermic. PMID:19138816

Aravindhan, Rathinam; Rao, Jonnalagadda Raghava; Nair, Balachandran Unni

2009-01-11

171

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...

172

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

Microsoft Academic Search

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

L. V. Sick

1976-01-01

173

Plutonium Uptake by the Green Alga Scenedesmus Obliquus (Turp) Kutz, as a Function of Isotope and Oxidation State.  

National Technical Information Service (NTIS)

This study was designed to determine the effect of plutonium chemical valence state on the availability of small concentrations of exp 238 Pu and exp 239 Pu to algae. The uptake experiments involved the green alga Scenedesmus obliquus, grown in batch cult...

M. F. Tkacik

1977-01-01

174

Effect of light, temperature, and pH on the accumulation of phenol by Selenastrum capricornutum, a green alga  

Microsoft Academic Search

The role of light, temperature, and pH was evaluated on the accumulation of phenol by the green alga, Selenastrum capricornutum. All three environmental variables had a significant effect on the accumulation of phenol. Differences in phenol accumulation were observed in algae that were cultured under light or dark conditions. In the light tests, the accumulation of phenol over a temperature

John L. Newsted

2004-01-01

175

Citric Acid Enhancement of Copper Sulfate Toxicity to the Blue-Green Algae 'Aphanizomenon flos-aquae' and 'Microcystis aeruginosa'.  

National Technical Information Service (NTIS)

Copper toxicity tests were carried out using two species of blue-green algae, Aphanizomenon flos-aquae and Microcystis aeruginosa. Copper concentrations of 300 microgram/liter or higher inhibited the growth of Aphanizomenon. The addition of 600 microgram ...

L. L. Ray

1978-01-01

176

Gain and loss of elongation factor genes in green algae  

Microsoft Academic Search

BACKGROUND: Two key genes of the translational apparatus, elongation factor-1 alpha (EF-1?) and elongation factor-like (EFL) have an almost mutually exclusive distribution in eukaryotes. In the green plant lineage, the Chlorophyta encode EFL except Acetabularia where EF-1? is found, and the Streptophyta possess EF-1? except Mesostigma, which has EFL. These results raise questions about evolutionary patterns of gain and loss

Ellen Cocquyt; Heroen Verbruggen; Frederik Leliaert; Frederick W Zechman; Koen Sabbe; Olivier De Clerck

2009-01-01

177

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

PubMed Central

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

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

1996-01-01

178

Ulvan, a Sulfated Polysaccharide from Green Algae, Activates Plant Immunity through the Jasmonic Acid Signaling Pathway  

PubMed Central

The industrial use of elicitors as alternative tools for disease control needs the identification of abundant sources of them. We report on an elicitor obtained from the green algae Ulva spp. A fraction containing most exclusively the sulfated polysaccharide known as ulvan-induced expression of a GUS gene placed under the control of a lipoxygenase gene promoter. Gene expression profiling was performed upon ulvan treatments on Medicago truncatula and compared to phytohormone effects. Ulvan induced a gene expression signature similar to that observed upon methyl jasmonate treatment (MeJA). Involvement of jasmonic acid (JA) in ulvan response was confirmed by detecting induction of protease inhibitory activity and by hormonal profiling of JA, salicylic acid (SA) and abscisic acid (ABA). Ulvan activity on the hormonal pathway was further consolidated by using Arabidopsis hormonal mutants. Altogether, our results demonstrate that green algae are a potential reservoir of ulvan elicitor which acts through the JA pathway.

Jaulneau, Valerie; Lafitte, Claude; Jacquet, Christophe; Fournier, Sylvie; Salamagne, Sylvie; Briand, Xavier; Esquerre-Tugaye, Marie-Therese; Dumas, Bernard

2010-01-01

179

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.

Hudson, Peggy R.; Waaland, J. Robert

1974-01-01

180

Purification and characterization of cytochrome c6 from the unicellular green alga Scenedesmus obliquus.  

PubMed

Purification of a soluble cytochrome c6 from the unicellular green alga Scenedesmus obliquus by a simple and rapid method is described. The purification procedure includes ammonium sulfate precipitation and non-denaturating PAGE. The N-terminal sequence of the first 20 amino acids was determined and shows 85% similarity and 75% identity to the sequence of cytochrome c6 from the green alga Monoraphidium braunii. The ferrocytochrome shows typical UV/VIS absorption peaks at 552.9, 521.9 and 415.7 nm. The apparent molecular mass was estimated to be 12 kDa by SDS-PAGE. EPR-spectroscopy at 20 K shows resonances indicative for two distinct low-spin heme forms. PMID:9463935

Wünschiers, R; Zinn, T; Linder, D; Schulz, R

181

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

SciTech Connect

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

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

1980-02-01

182

Molecular cloning and evolutionary analysis of the calcium-modulated contractile protein, centrin, in green algae and land plants  

Microsoft Academic Search

Centrin (= caltractin) is a ubiquitous, cytoskeletal protein which is a member of the EF-hand superfamily of calcium-binding proteins. A centrin-coding cDNA was isolated and characterized from the prasinophyte green alga Scherffelia dubia. Centrin PCR amplification primers were used to isolate partial, homologous cDNA sequences from the green algae Tetraselmis striata and Spermatozopsis similis. Annealing analyses suggested that centrin is

Debashish Bhattacharya; Jutta Steinkötter; Michael Melkonian

1993-01-01

183

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

Microsoft Academic Search

The Terrestrial Nitrogen-fixing Blue-green Algae, which are possessed of both photosynthesis and nitrogen fixation, are the leading organisms in the adverse circumstances. With their typical cell structures and physiological abilities, they are strongly resistant to drought, infertility etc. The growth of Terrestrial Nitrogen-fixing Blue-green Algae can rich the soils in nitrogen and organic compounds, which are benefit to other microbes

Yusuo Yang; Jiaqiang Lei

2003-01-01

184

Esfenvalerate toxicity to the cladoceran Ceriodaphnia dubia in the presence of green algae, Pseudokirchneriella subcapitata.  

PubMed

The presence of phytoplankton, like other particulate organic matter, can interfere with the effects of hydrophobic contaminants such as pyrethroid pesticides. However, the reduction or elimination of toxicity by algae added as food during testing is not taken into account in standard US EPA whole effluent toxicity (WET) zooplankton tests. On the other hand, WET test conditions may overestimate toxicity of such compounds in highly productive surface waters with high concentrations of detritus and other particulate matter. In addition, WET tests do not measure impaired swimming ability or predator avoidance behavior as an indicator of increased mortality risk. This study used a modified version of the US EPA WET Ceriodaphnia dubia acute test to investigate the effects of phytoplankton on toxicity of the pyrethroid insecticide, esfenvalerate. Animals were exposed simultaneously to different concentrations of esfenvalerate and green algae (Pseudokirchneriella subcapitata). Mortality and predation risk were recorded after 4 and 24 h. Algae at or below concentrations specified in the WET protocol significantly reduced mortality. Regardless, organisms exposed to esfenvalerate were unable to avoid simulated predation in the presence of algae at any concentration. After 12 h, esfenvalerate adsorbed to algae represented 68-99 % of the total amount recovered. The proportion of algae-bound insecticide increased with algal concentration indicating that conclusions drawn from toxicity tests in which algae are added as food must be interpreted with caution as the dissolved fraction of such hydrophobic contaminants is reduced. Additionally, our results strongly suggest that the EPA should consider adding ecologically-relevant endpoints such as swimming behavior to standard WET protocols. PMID:22975895

Brander, Susanne M; Mosser, Christopher M; Geist, Juergen; Hladik, Michelle L; Werner, Inge

2012-09-14

185

Effects of abiotic factors on nitrogen fixation by blue-green algae in Antarctica  

Microsoft Academic Search

In situ nitrogen fixation (acetylene reduction) was compared for three types of free-living terrestrial blue-green algae at the Vestfold Hills, Antarctica. Rates of acetylene reduction by foliose mats of Nostoc commume and felts of Calothrix ranged between 0.82 to 211.2 p mol C2H4 µg chla-1 hr-1 at ground temperatures of -4 to 9°C. Mucilaginous colonies of N. sphaericum were less

A. Davey

1983-01-01

186

Spectral hole burning of photosynthetic antenna of blue-green algae  

NASA Astrophysics Data System (ADS)

Photosystem II core antenna of blue-green algae Synechococcus isolated in gel was studied by optical hole burning spectroscopy at 4·2 K. Persistent holes were burned into fluorescence spectra throughout the region 680 696 nm. The hole width extrapolated to zero burning fluence yielded a value 1·0±0·2 cm-1. A theoretical interpretation of the hole profile in fluorescence is presented. The dependence of saturated hole depth on burning wavelength is related to inhomogeneous site distribution function.

Vácha, M.; Adamec, F.; Ambrož, M.; Dian, J.; Hála, J.

1991-07-01

187

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

Microsoft Academic Search

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

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

1981-01-01

188

Electron pathways involved in H 2-metabolism in the green alga Scenedesmus obliquus  

Microsoft Academic Search

The green alga Scenedesmus obliquus is capable of both uptake and production of H2 after anaerobic adaptation (photoreduction of CO2 or photohydrogen production). The essential enzyme for H2-metabolism is a NiFe-hydrogenase with a [2Fe–2S]-ferredoxin as its natural redox partner. Western blot analysis showed that the hydrogenase is constitutively expressed. The Km values were 79.5 ?M and 12.5 ?M, determined with

Röbbe Wünschiers; Horst Senger; Rüdiger Schulz

2001-01-01

189

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

Microsoft Academic Search

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

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

2011-01-01

190

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

Microsoft Academic Search

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

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

1995-01-01

191

Molecular Phylogeny of Conjugating Green Algae (Zygnemophyceae, Streptophyta) Inferred from SSU rDNA Sequence Comparisons  

Microsoft Academic Search

Nuclear-encoded SSU rDNA sequences have been obtained from 64 strains of conjugating green algae (Zygnemophyceae, Streptophyta,\\u000a Viridiplantae). Molecular phylogenetic analyses of 90 SSU rDNA sequences of Viridiplantae (inciuding 78 from the Zygnemophyceae)\\u000a were performed using complex evolutionary models and maximum likelihood, distance, and maximum parsimony methods. The significance\\u000a of the results was tested by bootstrap analyses, deletion of long-branch taxa,

Andrey A. Gontcharov; Birger Marin; Michael Melkonian

2003-01-01

192

Kinetic evaluation of photosensitivity in genetically engineered neurons expressing green algae light-gated channels  

Microsoft Academic Search

Neurons become photosensitive by genetically introducing one of green algae-derived protein, channelrhodopsin-2 (ChR2). Here, we quantitatively investigated the rapidness of the light-gated current of ChR2 expressed in PC12 cells using blue light-emitting diode (LED) light. The light-gated current consists of two components, inactivating and non-inactivating. The magnitude of inactivating component was almost linearly related to the light intensity. The non-inactivating

Toru Ishizuka; Masaaki Kakuda; Rikita Araki; Hiromu Yawo

2006-01-01

193

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

Microsoft Academic Search

A set of chlorophyll fluorescence methods, including PEA (Plant Efficiency Analyser), PAM (Pulse Amplitude Modulated fluorometer),\\u000a 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\\u000a by the energetic disconnection, smaller antenna size, elevated

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

2007-01-01

194

Effects of nutrients present in Bold’s basal medium on the green alga Stigeoclonium pascheri  

Microsoft Academic Search

The effects of varying concentrations of nutrients present in Bold’s basal medium on the extent of colony formation from vegetative\\u000a fragments, sporulation and spore germination of the green algaStigeoclonium poscheri were studied. A decrease of colony formation was observed in media deficient in MgSO4, NaNO3, phosphates, and containing a 10-fold increase of H3BO3. Sporulation decreased in the same media. However,

S. C. Agrawal; Y. S. R. K. Sarma

1982-01-01

195

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

Microsoft Academic Search

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

Satoshi Nakai; Yutaka Inoue; Masaaki Hosomi; Akihiko Murakami

2000-01-01

196

The influence of blue-green algae on the biological amelioration of alkali soils  

Microsoft Academic Search

Virgin alkali (sodic) soils have a high pH and high exchangeable Na and are often barren. Blue-green algae, however, tolerate excess Na and grow extensively on the soil surface in wet seasons. Experiments using a highly degraded alkali soil (silt loam, pH 10.3, electrical conductivity 3.5 dS m-1, 90% exchangeable Na) were conducted in soil columns, with or without gypsum,

D. L. N. Rao; R. G. Burns

1991-01-01

197

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

198

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

Microsoft Academic Search

Cloned HinfI fragments of the plasmid-like 2.2-kb DNA from the green alga Ernodesmis verticillata (Kützing) Børgesen hybridized solely to single or double bands within the 2.2-kb DNA in genomic Southern blots. Heterologous\\u000a probes for nuclear and chloroplast genes hybridized only to high-molecular-weight (HMW) DNA. Thus, the low-molecular-weight\\u000a (LMW) DNA is extrachromosomal and lacks extensive homology to nuclear or chloroplast genes.

John W. La Claire; Carie M. Loudenslager; Giuseppe C. Zuccarello

1998-01-01

199

Class XIII myosins from the green alga Acetabularia : driving force in organelle transport and tip growth?  

Microsoft Academic Search

The green alga Acetabularia cliftonii (Dasycladales) contains at least two myosin genes, which already have been assigned class XIII of the myosin superfamily\\u000a (Cope et al., 1996, Structure 4: 969–987). Here we report a complete analysis of their gene structure and their corresponding transcripts\\u000a Aclmyol and Aclmyo2. Despite promising Northern blot data no evidence for alternative splicing could be found.

Oliver Vugrek; Heiko Sawitzky; Diedrik Menzel

2003-01-01

200

Intron-specific RNA binding proteins in the chloroplast of the green alga Chlamydomonas reinhardtii  

Microsoft Academic Search

Mitochondria and chloroplasts both contain group II introns which are believed to be the ancestors of nuclear spliceosomal introns. We used the mitochondrial group II intron rI1 from the green alga Scenedesmus obliquus for biochemical characterization of intron-specific RNA binding proteins. rI1 is correctly spliced from a chloroplast precursor RNA when integrated into the chloroplast genome of Chlamydomonas reinhardtii. Glycerol

Astrid A Bunse; Jörg Nickelsen; Ulrich Kück

2001-01-01

201

The chloroplast sulfate transport system in the green alga Chlamydomonas reinhardtii  

Microsoft Academic Search

The genome of the model unicellular green alga Chlamydomonas reinhardtii contains four distinct genes, SulP, SulP2, Sbp and Sabc, which together are postulated to encode a chloroplast envelope-localized sulfate transporter holocomplex. In this work,\\u000a evidence is presented that regulation of expression of SulP2, Sbp and Sabc is specifically modulated by sulfur availability to the cells. Induction of transcription and higher

Pia Lindberg; Anastasios Melis

2008-01-01

202

Calcium oxalate crystals in the aragonite-producing green alga penicillus and related genera.  

PubMed

Calcium oxalate crystals occur in the marine green algae Penicillus, Rhipocephalus, and Udotea, known as producers of sedimentary aragonite needles. In contrast to the externally deposited aragonite crystals which are generally < 15 micrometers long, the oxalate crystals are larger (up to 150 micrometers) and are located in the vacuolar system of the plant. No calcium oxalate was found in the related but noncalcifying genera Avrainvillea and Cladocephalus. PMID:17780990

Friedmann, E I; Roth, W C; Turner, J B; McEwen, R S

1972-09-01

203

Observations on tolerance to heavy metals of four green algae in relation to pH  

Microsoft Academic Search

The inhibition of growth by different concentration of eight heavy metals: Cd, Cr, Co, Cu, Hg, Ni, Se and Tl, in inorganic medium at pH 3 and 6.5, was studied in four green algae: Chlorella protothecoides Krüger, Chlorella saccharophila (Krüger) Migula, Coenochloris sp. and Stichococcus bacillaris Naegeli.The results suggest that pH has an important effect on heavy metal toxicity in

Giovanni Aliotta; Gabriele Pinto; Antonino Pollio

1983-01-01

204

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

205

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

PubMed Central

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

Voytsekh, Olga; Mittag, Maria; Schuster, Stefan

2011-01-01

206

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

207

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

208

Evidence of electrical potential changes in photophobically reacting blue-green algae  

Microsoft Academic Search

The correlation between photophobic responses and light-induced electric potential changes has been studied in the blue-green alga Phormidium uncinatum.1.The photophobic reaction time depends on both length of preillumination and presentation time of stimulus. Under optimal conditions a reaction time of about 10 s has been determined.2.Light-induced potential changes can be measured by means of external electrodes with a small gap

Donat-P. Häder

1978-01-01

209

Epiphytic Algae on Deep-Dwelling Bryophytes in Waldo Lake, Oregon  

Microsoft Academic Search

Benthic bryophyte samples that were retrieved in 1990 from depths of 45 m to 110 m in Waldo Lake were analyzed in 1999 for epiphytes. Rewetting of dried material, most of which was liverworts, indicated extensive colonization by filamentous green and blue-green algae, diatoms and aquatic fungi. Bulbocheate, Oedogonium and Stigonema were the three most common filamentous genera present at

N. S. Geiger

2000-01-01

210

Unique regulation of the Calvin cycle in the ultrasmall green alga Ostreococcus.  

PubMed

Glyceraldehyde-3-phosphate dehydrogenase (GapAB) and CP12 are two major players in controlling the inactivation of the Calvin cycle in land plants at night. GapB originated from a GapA gene duplication and differs from GapA by the presence of a specific C-terminal extension that was recruited from CP12. While GapA and CP12 are assumed 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 that two closely related prasinophycean green algae, Ostreococcus tauri and Ostreococcus lucimarinus, also possess a GapB gene, while CP12 is missing. This remarkable finding either antedates the GapA/B gene duplication or indicates a lateral recruitment. Moreover, Ostreococcus is the first case where the crucial CP12 function may be completely replaced by GapB-mediated GapA/B aggregation. PMID:17457634

Robbens, Steven; Petersen, Jörn; Brinkmann, Henner; Rouzé, Pierre; Van de Peer, Yves

2007-04-24

211

Evolutionary trajectories explain the diversified evolution of isogamy and anisogamy in marine green algae.  

PubMed

The evolution of anisogamy (the production of gametes of different size) is the first step in the establishment of sexual dimorphism, and it is a fundamental phenomenon underlying sexual selection. It is believed that anisogamy originated from isogamy (production of gametes of equal size), which is considered by most theorists to be the ancestral condition. Although nearly all plant and animal species are anisogamous, extant species of marine green algae exhibit a diversity of mating systems including both isogamy and anisogamy. Isogamy in marine green algae is of two forms: isogamy with extremely small gametes and isogamy with larger gametes. Based on disruptive selection for fertilization success and zygote survival (theory of Parker, Baker, and Smith), we explored how environmental changes can contribute to the evolution of such complex mating systems by analyzing the stochastic process in the invasion simulations of populations of differing gamete sizes. We find that both forms of isogamy can evolve from other isogamous ancestors through anisogamy. The resulting dimensionless analysis accounts for the evolutionary stability of all types of mating systems in marine green algae, even in the same environment. These results imply that evolutionary trajectories as well as the optimality of gametes/zygotes played an important role in the evolution of gamete size. PMID:22869736

Togashi, Tatsuya; Bartelt, John L; Yoshimura, Jin; Tainaka, Kei-ichi; Cox, Paul Alan

2012-08-06

212

The impact of aluminium on green algae isolated from two hydrochemically different headwater streams, Bavaria, Germany.  

PubMed

Two strains of green algae (Scenedesmus sp. and Chlorella sp.) have been isolated from two headwater streams differing in stream chemistry (Eger river: acidic, low alkalinity; Püttlach river: slightly alkaline, high alkalinity). In this study the growth response of these indigenous algae to increased concentrations of aluminium (Al) is investigated. A semi-continuous culture technique was used for Al-toxicity studies. Algal response was determined by calculating growth rates from turbidity and cell counts. Those Al-species which are well known to be toxic were estimated by equilibrium calculations using the WATEQ computer program (Truesdall & Jones, 1973). The pH-value of the culture media was usually pH=5, except for one of the test series. Tested concentrations ranged from c=4 to 220 micromol litre(-1). The isolated strains of green algae were highly sensitive to increased Al-concentrations. The strain isolated from the Püttlach river was more sensitive than the Eger river algae. A total growth inhibition occurs at Al-concentrations of c=4 micromol litre(-1) if the whole Al was added at once. If Al was added gradually into the growth media the response of the algae was delayed. This is due to Al-enrichment in cells. In our long term toxicity studies, growth inhibition occurs even at nearly neutral pH-conditions (pH=6.5) although Al toxicity is expected at pH-values less than pH=5.5. This new result confirms the need of long-term studies in continuous cultures under simulated natural conditions. This might be the only way to achieve valid conclusions about the fate and the toxicity of environmental pollutants. PMID:15092226

Lindemann, J; Holtkamp, E; Herrmann, R

1990-01-01

213

Carbon acquisition by diatoms  

Microsoft Academic Search

Diatoms are responsible for up to 40% of primary productivity in the ocean, and complete genome sequences are available for\\u000a two species. However, there are very significant gaps in our understanding of how diatoms take up and assimilate inorganic\\u000a C. Diatom plastids originate from secondary endosymbiosis with a red alga and their Form ID Rubisco (ribulose-1,5-bisphosphate\\u000a carboxylase-oxygenase) from horizontal gene

Karen Roberts; Espen Granum; Richard C. Leegood; John A. Raven

2007-01-01

214

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

PubMed

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

Trémouillaux-Guiller, Jocelyne; Huss, Volker A R

2007-05-15

215

Cell death upon H(2)O(2) induction in the unicellular green alga Micrasterias.  

PubMed

In the present study, we investigated whether the unicellular green alga Micrasterias denticulata is capable of executing programmed cell death (PCD) upon experimental induction, and which morphological, molecular and physiological hallmarks characterise this. This is particularly interesting as unicellular freshwater green algae growing in shallow bog ponds are exposed to extreme environmental conditions, and the capacity to perform PCD may be 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 for many years and details on its growth properties, physiology and ultrastructure throughout the cell cycle are well known. Treatments with low concentrations of H(2)O(2) are known to induce PCD in other organisms, resulting in severe ultrastructural changes to organelles, as observed in TEM. These include deformation and part disintegration of mitochondria, abnormal dilatation of cisternal rims of dictyosomes, 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 was detected, which was abrogated by a caspase-3 inhibitor. Photosynthetic activity measured by fast chlorophyll fluorescence decreased as a consequence of H(2)O(2) exposure, whereas pigment composition, except for a reduction in carotenoids, was the same as in untreated controls. TUNEL positive staining and ladder-like degradation of DNA, both frequently regarded as a hallmark of PCD in higher plants, could only be detected in dead Micrasterias cells. PMID:18950431

Darehshouri, A; Affenzeller, M; Lütz-Meindl, U

2008-11-01

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

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.

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

2010-01-01

218

Ca2+ signalling in plants and green algae--changing channels.  

PubMed

Eukaryotic cells generate cytosolic Ca2+ signals via Ca2+-conducting channels in cellular membranes. Plants and animals exhibit substantial differences in their complement of Ca2+ channels. In particular, the four-domain voltage-dependent Ca2+ channels, transient receptor potential channels and inositol (1,4,5)-trisphosphate receptors, which have important roles in animal physiology, are all absent from land plants. Recent evidence from biochemical and genomic studies has indicated that representatives of these classes of Ca2+ channels are present in members of the green plant lineage, the chlorophyte algae. This indicates that the Ca2+-signalling mechanisms absent from land plants were, in fact, present in ancestral eukaryotes and were lost by land plants after their divergence from the chlorophyte algae. PMID:18703378

Wheeler, Glen L; Brownlee, Colin

2008-08-12

219

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

2013-02-21

220

PredAlgo: a new subcellular localization prediction tool dedicated to green algae.  

PubMed

The unicellular green alga Chlamydomonas reinhardtii is a prime model for deciphering processes occurring in the intracellular compartments of the photosynthetic cell. Organelle-specific proteomic studies have started to delineate its various subproteomes, but sequence-based prediction software is necessary to assign proteins subcellular localizations at whole genome scale. Unfortunately, existing tools are oriented toward land plants and tend to mispredict the localization of nuclear-encoded algal proteins, predicting many chloroplast proteins as mitochondrion targeted. We thus developed a new tool called PredAlgo that predicts intracellular localization of those proteins to one of three intracellular compartments in green algae: the mitochondrion, the chloroplast, and the secretory pathway. At its core, a neural network, trained using carefully curated sets of C. reinhardtii proteins, divides the N-terminal sequence into overlapping 19-residue windows and scores the probability that they belong to a cleavable targeting sequence for one of the aforementioned organelles. A targeting prediction is then deduced for the protein, and a likely cleavage site is predicted based on the shape of the scoring function along the N-terminal sequence. When assessed on an independent benchmarking set of C. reinhardtii sequences, PredAlgo showed a highly improved discrimination capacity between chloroplast- and mitochondrion-localized proteins. Its predictions matched well the results of chloroplast proteomics studies. When tested on other green algae, it gave good results with Chlorophyceae and Trebouxiophyceae but tended to underpredict mitochondrial proteins in Prasinophyceae. Approximately 18% of the nuclear-encoded C. reinhardtii proteome was predicted to be targeted to the chloroplast and 15% to the mitochondrion. PMID:22826458

Tardif, Marianne; Atteia, Ariane; Specht, Michael; Cogne, Guillaume; Rolland, Norbert; Brugière, Sabine; Hippler, Michael; Ferro, Myriam; Bruley, Christophe; Peltier, Gilles; Vallon, Olivier; Cournac, Laurent

2012-07-23

221

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

222

Cytochrome c6 from the green alga Monoraphidium braunii. Crystallization and preminary diffraction studies.  

PubMed

Cytochrome c(6), a plastocyanin functionally interchangeable electron carrier between the chlorophyll molecule P700 of photosystem I and cytochrome f from cytochrome b(6)f complex, has been isolated from the green alga Monoraphidium braunii and crystallized by the vapour-diffusion technique in sodium citrate. Crystals belong to space group R3, with cell dimensions a = b = 51.93 (5) and c = 80.5 (1) A (hexagonal axes), with one molecule per asymmetric unit. They diffract beyond 1.9 A under a Cu Kalpha rotating-anode source, with an anomalous signal that allows the positioning of the heme Fe atom in the unit cell. PMID:15299324

Frazão, C; Dias, J M; Matias, P M; Romão, M J; Carrondo, M A; Hervás, M; Navarro, J A; de la Rosa, M; Sheldrick, G M

1995-03-01

223

Hypocholesterolemic effect of Nostoc commune var. sphaeroides Kützing, an edible blue-green alga  

Microsoft Academic Search

Background  Intake of an edible blue-green alga Nostoc commune var. sphaeroides Kützing (N. Commune) has been shown to lower plasma total cholesterol concentration, but the mechanisms behind the hypocholesterolemic effect\\u000a have not been elucidated.\\u000a \\u000a \\u000a \\u000a Aim of the study  To elucidate the mechanisms underlying the cholesterol-lowering effect of N. commune in mice. \\u000a \\u000a \\u000a \\u000a Methods  Male C57BL\\/6J mice were fed the AIN-93 M diet supplemented with 0

Heather E. Rasmussen; Kara R. Blobaum; Elliot D. Jesch; Chai Siah Ku; Young-Ki Park; Fan Lu; Timothy P. Carr; Ji-Young Lee

2009-01-01

224

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

225

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

226

Lytic Organisms and Photooxidative Effects: Influence on Blue-Green Algae (Cyanobacteria) in Lake Mendota, Wisconsin  

PubMed Central

The effects of exposure to high light intensities on blue-green algal (cyanobacterial) populations were examined in Lake Mendota, Wis. The algal populations were shown to be susceptible to inhibition of photosynthetic activity and pigment bleaching as a result of exposure. These effects generally influence only a small percentage of the lake population and thus are probably not important in causing major declines in chlorophyll a. Lytic organisms were shown to increase in numbers in the lake in response to the seasonal development of blue-green algae, reaching values of greater than 1,000 plaque-forming units per ml in midsummer. Both bacteria and protozoa were observed in plaque zones, but it could not be determined whether these lytic organisms had a major role in algal biomass declines.

Fallon, R. D.; Brock, T. D.

1979-01-01

227

(Carbon and hydrogen metabolism of green algae in light and dark)  

SciTech Connect

The focus of this project was the elucidation of anaerobic metabolism in ecuaryotic green algae, chlamydomonas reinhardii. Chlamydomonas is a versatile organism that can grow under disparate conditions such as fresh water lakes and sewage ponds. The cell an photoassimilate CO{sub 2} aerobically and anaerobically, the latter after adaptation'' to a hydrogen metabolism. It can recall the knallgas or oxyhydrogen reaction and utilize hydrogen the simplest of all reducing agents for the dark assimilation of CO{sub 2} by the photosynthetic carbon reduction cycle. The dark reduction with hydrogen lies on the border line between autotrophic and heterotrophic carbon assimilation. Both autotrophic and heterotrophic bacteria are known in which molecular hydrogen can replace either inorganic or organic hydrogen donors. Here the dark reduction of CO{sub 2} acquires a particular importance since it occurs in the same cell that carries on photoreduction and photosynthesis. We will demonstrate here that the alga chloroplast possesses a respiratory capacity. It seems likely that Chlamydomonas may have retained the chloroplastic respiratory pathway because of the selective advantage provided to the algae under a wide range of environmental conditions that the cells experience in nature. The ability to cycle electrons and poise the reduction level of the photosynthetic apparatus under aerobic and microaerobic conditions could allow more efficient CO{sub 2} fixation and enhanced growth under unfavorable conditions or survival under more severe conditions.

Not Available

1990-01-01

228

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

NASA Astrophysics Data System (ADS)

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

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

2008-03-01

229

A comparison of the role of two blue-green algae in THM and HAA formation.  

PubMed

The contribution of two blue-green algae species, Anabaena flos-aquae and Microcystis aeruginosa, to the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) was investigated. The experiments examined the formation potential of these disinfection by-products (DBPs) from both algae cells and extracellular organic matter (EOM) during four algal growth phases. Algal cells and EOM of Anabaena and Microcystis exhibited a high potential for DBP formation. Yields of total THMs (TTHM) and total HAAs (THAA) were closely related to the growth phase. Reactivity of EOM from Anabaena was slightly higher than corresponding cells, while the opposite result was found for Microcystis. Specific DBP yields (yield/unit C) of Anabaena were in the range of 2-11micromol/mmol C for TTHM and 2-17micromol/mmol C for THAA, while those of Microcystis were slightly higher. With regard to the distributions of individual THM and HAA compounds, differences were observed between the algae species and also between cells and EOM. The presence of bromide shifted the dominant compounds from HAAs to THMs. PMID:19457536

Huang, J; Graham, N; Templeton, M R; Zhang, Y; Collins, C; Nieuwenhuijsen, M

2009-05-03

230

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.

Teyssèdre, B.

2007-09-01

231

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.

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

2005-01-01

232

Hemagglutination method for detection of freshwater cyanobacteria (blue-green algae) toxins.  

PubMed Central

Strains of the freshwater cyanobacteria (blue-green algae) Anabaena flosaquae and Microcystis aeruginosa produced toxins that caused intermittent but repeated cases of livestock, waterfowl, and other animal deaths. They also caused illness, especially gastrointestinal, in humans. The most common group of toxins produced by these two species were peptide toxins termed microcystin, M. Aeruginosa type c, and anatoxin-c. A method was found to detect the toxins which utilizes their ability to cause agglutination of isolated blood cells from mice, rats, and humans. The method could detect the toxin in samples from natural algal blooms, laboratory cultures, and toxin extracts. The method consists of: (i) washing lyophilized cyanobacteria cells with physiological saline (0.9% NaCl), (ii) centrifuging the suspension and then mixing portions of the cell-free supernatant with equal volumes of saline-washed erythrocytes in V-shaped microtiter plates, (iii) allowing the mixture to stand for 3 to 4 h, and (iv) scoring the presence of the toxin as indicated by blood cell agglutination. Nontoxic strains, as determined by intraperitoneal mouse bioassay of cyanobacteria or green algae, did not produce an agglutination response. Images

Carmichael, W W; Bent, P E

1981-01-01

233

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

2012-09-12

234

Biochemical Basis of Obligate Autotrophy in Blue-Green Algae and Thiobacilli  

PubMed Central

Differential rates of incorporation of sugars, organic acids, and amino acids during autotrophic growth of several blue-green algae and thiobacilli have been determined. In obligate autotrophs (both blue-green algae and thiobacilli), exogenously furnished organic compounds make a very small contribution to cellular carbon; acetate, the most readily incorporated compound of those studied, contributes about 10% of newly synthesized cellular carbon. In Thiobacillus intermedius, a facultative chemoautotroph, acetate contributes over 40% of newly synthesized cellular carbon, and succinate and glutamate almost 90%. In the obligate autotrophs, carbon from pyruvate, acetate, and glutamate is incorporated into restricted groups of cellular amino acids, and the patterns of incorporation in all five organisms are essentially identical. These patterns suggest that the tricarboxylic acid cycle is blocked at the level of ?-ketoglutarate oxidation. Enzymatic analyses confirmed the absence of ?-ketoglutarate dehydrogenase in the obligate autotrophs, and also revealed that they lacked reduced nicotinamide adenine dinucleotide oxidase, and had extremely low levels of malic and succinic dehydrogenase. These enzymatic deficiencies were not manifested by the two facultative chemoautotrophs examined. On the basis of the data obtained, an interpretation of obligate autotrophy in both physiological and evolutionary terms has been developed.

Smith, Arnold J.; London, Jack; Stanier, Roger Y.

1967-01-01

235

Estrogenic activity in extracts and exudates of cyanobacteria and green algae.  

PubMed

Here is presented some of the first information on interactions of compounds produced by cyanobacteria and green algae with estrogen receptor signaling. Estrogenic potency of aqueous extracts and exudates (culture spent media with extracellular products) of seven species of cyanobacteria (10 different laboratory strains) and two algal species were assessed by use of in vitro trans-activation assays. Compounds produced by cyanobacteria and algae, and in particular those excreted from the cells, were estrogenic. Most exudates were estrogenic with potencies expressed at 50% of the maximum response under control of the estrogen receptor ranging from 0.2 to 7.2 ng 17?-estradiol (E(2)) equivalents (EEQ)/L. The greatest estrogenic potency was observed for exudates of Microcystis aerigunosa, a common species that forms water blooms. Aqueous extracts of both green algae, but only one species of cyanobacteria (Aphanizomenon gracile) elicited significant estrogenicity with EEQ ranging from 15 to 280 ng 17?-estradiol (E(2))/g dry weight. Scenedesmus quadricauda exudates and extracts of Aphanizomenon flos-aquae were antagonistic to the ER when coexposed to E(2). The EEQ potency was not correlated with concentrations of cyanotoxins, such as microcystin and cylindrospermopsin, which suggests that the EEQ was comprised of other compounds. The study demonstrates some differences between the estrogenic potency of aqueous extracts prepared from the same species, but of different origin, while the effects of exudates were comparable within species. The observed estrogenic potencies are important namely in relation to the possible mass expansion of cyanobacteria and release of the active compounds into surrounding water. PMID:22208753

Sychrová, E; Št?pánková, T; Nováková, K; Bláha, L; Giesy, J P; Hilscherová, K

2011-11-24

236

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

237

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

PubMed

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

Zoller, Stefan; Lutzoni, François

2003-12-01

238

Survival and reproduction of some blue-green and green algae as affected by sewage water, fertilizer factory effluent, brassica oil, phenol, toluene and benzene  

Microsoft Academic Search

Fourteen blue-green and green algae survived for widely different time periods ranging between 22–102 d in control culture\\u000a medium. Irrespective of their long or short survival period in control cultures, their pro- or eukaryotic nature, their different\\u000a morphological types or natural habitats, they all survived for a short time period ranging between 3–8 d in sewage water,\\u000a 5–10 d in

S. C. Agrawal; S. Gupta

2009-01-01

239

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

240

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

PubMed Central

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

Radmer, Richard; Ollinger, Otto

1980-01-01

241

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

242

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

Microsoft Academic Search

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

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

1978-01-01

243

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

Microsoft Academic Search

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

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

1981-01-01

244

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 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

Peter H. Homann

2003-01-01

245

Novel antibacterial proteins from the microbial communities associated with the sponge Cymbastela concentrica and the green alga Ulva australis.  

PubMed

The functional metagenomic screening of the microbial communities associated with a temperate marine sponge and a green alga identified three novel hydrolytic enzymes with antibacterial activities. The results suggest that uncultured alpha- and gammaproteobacteria contain new classes of proteins that may be a source of antibacterial agents. PMID:21183639

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

2010-12-23

246

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

PubMed

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

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

2012-07-26

247

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

PubMed Central

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

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

1992-01-01

248

Analysis of lysine-rich histones from the unicellular green alga Chlamydomonas reinhardtii.  

PubMed

The H1 histones of the unicellular green alga Chlamydomonas reinhardtii were extracted from isolated nuclei, fractionated by high performance liquid chromatography, and analyzed by two-dimensional electrophoresis, peptide mapping, and N-terminal sequencing. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of 5% perchloric acid extracts of isolated C. reinhardtii nuclei revealed two H1 proteins (H1A and H1B). Two-dimensional gel analysis did not reveal heterogeneity of either algal H1 protein, but did detect differences in the hydrophobic amino acid content of the C. reinhardtii H1A and H1B. Digestion of H1A and H1B with V8 protease revealed two distinctly different peptide maps. C. reinhardtii H1 peptide maps were not at all similar to those of Pisum H1, but algal and pea H2B peptide maps did show some peptides in common. Seventeen amino acid residues were obtained from C. reinhardtii H1A amino terminal sequencing, while the H1B N-terminus was blocked. A search of protein data bases revealed no sequence homology of the H1A N-terminus with any known protein. Chlamydomonas histones fractionated by high performance liquid chromatography revealed minor components (histone variants) for H2A and H2B. The amino acid composition of Chlamydomonas lysine-rich histones was compared to those of various other unicellular algae. PMID:10568039

Morris, R L; Salinger, A P; Rizzo, P J

249

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

PubMed Central

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

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

1999-01-01

250

Genetic transformation of Pseudochoricystis ellipsoidea, an aliphatic hydrocarbon-producing green alga.  

PubMed

Pseudochoricystis ellipsoidea is a recently isolated unicellular green alga, which is classified within the family Trebouxiophyceae. This alga has a unique ability to synthesize and accumulate intracellularly a significant amount of aliphatic hydrocarbons. To elucidate molecular mechanisms of the hydrocarbon production in this organism, the development of genetic methods including DNA transformation methods are important. Towards the goal, we constructed several plasmids in which neomycin phosphotransferase II-encoding G418-resistant gene (nptII) is flanked by a P. ellipsoidea-derived promoter and terminator. These plasmids were introduced into P. ellipsoidea cells through particle-gun bombardment, and transformants were screened among G418-resistant cells by PCR amplification of plasmid-borne genes. Southern blot analysis demonstrated that the exogenous DNA was integrated into the genome of the transformants. Furthermore, the expression of nptII was confirmed at the transcript and protein levels by RT-PCR and immunoblot analyses, respectively. These results clearly indicated that a genetic transformation system was successfully established for P. ellipsoidea. PMID:22449745

Imamura, Sousuke; Hagiwara, Daisuke; Suzuki, Fumi; Kurano, Norihide; Harayama, Shigeaki

2012-01-01

251

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

SciTech Connect

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

Stratton, G.W.

1987-06-01

252

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

253

Ultrastructure of the siphonaceous green alga Halimeda cuneata, with emphasis on the cytoskeleton.  

PubMed

Cytoplasm streaming is a fundamental process for the transport of molecules and organelles in plant cells. In vegetative filaments of the coenocytic green alga, Halimeda cuneata Hering, the spatial organisation of microtubules in the cytoplasmic layer, was observed under transmission electron microscopy. A cross section of a cortical filament shows a tubular cell wall enclosing a peripheral layer of cytoplasm with numerous chloroplasts, amyloplasts, nuclei, mitochondria and microtubules surrounding a small central vacuole. Towards the thallus medulla the central vacuole enlarges considerably and the cytoplasm becomes gradually reduced to a thin parietal layer, the number of organelles is reduced and the quantity of microtubules increases. Therefore, most of the thallus volume is occupied by the huge central vacuole which extends throughout the coenocytic filaments. Microtubules run longitudinally, being about 0.05 microm from each other. Some microtubules were observed in close association to cell organelles. PMID:20434347

Bouzon, Zenilda Laurita; Bandeira-Pedrosa, Maria Elizabeth; Schmidt, Eder Carlos

2010-04-09

254

C-phycocyanin and allophycocyanin in two species of blue-green algae.  

PubMed

1. The biliproteins C-phycocyanin and allophycocyanin were purified from the blue-green alga Anabaena variabilis by ammonium sulphate fractionation and gel filtration. 2. An assay procedure that enabled the proportion of the two pigments, present as a mixture, to be determined was devised by using the data provided by spectrophotometric analysis of the purified biliproteins. 3. The degree of association and relative proportions of the two pigments were analysed by the application of this procedure to the components separated by thin-layer gel filtration. 4. The C-phycocyanin/allophycocyanin ratio remained essentially constant in algal extracts prepared at various stages throughout the growth cycle or after growth under conditions of reduced illumination. 5. The behaviour of the C-phycocyanin aggregate species from Anacystis nidulans suggested that they were of appreciably lower molecular weight than those observed in extracts of Anabaena variabilis. PMID:5637347

Craig, I W; Carr, N G

1968-01-01

255

Kinetic and equilibrium studies on biosorption of basic blue dye by green macro algae Caulerpa scalpelliformis.  

PubMed

Dynamic batch experiments were carried out for the biosorption of basic blue dye on to the green macro algae Caulerpa scalpelliformis. The factors affecting the sorption process such as the initial concentration of the dye, pH of the solution, the adsorbent dosage and the time of contact were studied. It has been observed that the sorption process was significantly affected by the pH of the initial dye solution. The sorption kinetics was found to follow the second-order kinetic model. The Boyd's plot confirmed the external mass transfer as the rate-limiting step. The average effective diffusion coefficient was found to be 1.652 x 10(- 5) cm(2)/s. Sorption equilibrium studies demonstrated that the biosorption followed Freundlich isotherm model, which implies a heterogeneous sorption phenomenon. Optimized parameters were used to treat the commercial effluent containing the dye. Complete color removal was observed in two stages of treatment with the seaweed. PMID:17454369

Aravindhan, Rathinam; Rao, Jonnalagadda Raghava; Nair, Balachandran Unni

2007-04-01

256

Characteristics of Nitrate Reduction in a Mutant of the Blue-Green Alga Agmenellum quadruplicatum.  

PubMed

Characteristics of nitrate reduction in terms of nitrite production in an N-methyl-N'-nitro-N-nitrosoguanidine-induced mutant of the blue-green alga Agmenellum quadruplicatum are described. Following induction of nitrate reduction a linear rate of nitrite production proportional to cell concentration was observed. Rate of nitrite production and growth rate showed similar responses to pH, temperature, and light intensity. If required, only trace amounts of carbon dioxide were necessary for nitrite production. Atmospheres of oxygen or nitrogen inhibited production of nitrite. In addition, a low but constant rate of nitrite production was observed in the dark. Nitrite production by mutant AQ-6 was studied in terms of photosynthesis. As nitrite production proceeded, rate of photosynthesis declined. Ultraviolet irradiation and 3-(3,4-dichlorophenyl)-1, 1-dimethylurea poisoning did not prevent nitrite production. The action spectrum of nitrite production was chlorophyll a-like. PMID:16658328

Stevens, S E; Van Baalen, C

1973-02-01

257

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

2011-02-01

258

Racemosins A and B, two novel bisindole alkaloids from the green alga Caulerpa racemosa.  

PubMed

Racemosin A (1), a structurally unique bisindole alkaloid possessing the seco-indolo[3,2-a]carbazole skeleton with two uncommon indolinenone units both conjugated with a methyl propenoate moiety, and its unusual cyclized derivative, racemosin B (2), were isolated from the green alga Caulerpa racemosa, together with the most commonly encountered pigment in the genus Caulerpa, caulerpin (3). Their structures were elucidated by extensive spectroscopic analysis and by comparison with data for related known compounds. A plausible biosynthetic pathway of 1 and 2 was proposed. In a neuro-protective assay, compound 1 significantly attenuated the A?25-35-induced SH-SY5Y cell damage with a 14.6% increase in cell viability at the concentration of 10?M when compared to epigallocatechin gallate (EGCG, 16.57% increase at 10?M) as the positive control. PMID:23978579

Liu, Ding-Quan; Mao, Shui-Chun; Zhang, Hai-Yan; Yu, Xiao-Qing; Feng, Mei-Tang; Wang, Bin; Feng, Li-Hua; Guo, Yue-Wei

2013-08-24

259

Purification and characterization of phycocyanin from the blue-green alga Aphanizomenon flos-aquae.  

PubMed

Aphanizomenon flos-aquae (AFA) is a blue-green alga and represents a nutrient-dense food source. In this study the presence of phycocyanin (PC), a blue protein belonging to the photosynthetic apparatus, has been demonstrated in AFA. An efficient method for its separation has been set up: PC can be purified by a simple single step chromatographic run using a hydroxyapatite column (ratio A620/A280 of 4.78), allowing its usage for health-enhancing properties while eliminating other aspecific algal components. Proteomic investigation and HPLC analysis of purified AFA phycobilisomes revealed that, contrary to the well-characterized Synechocystis and Spirulina spp., only one type of biliprotein is present in phycobilisomes: phycocyanins with no allo-phycocyanins. Two subunit polypeptides of PC were also separated: the beta subunit containing two bilins as chromophore and the alpha subunit containing only one. PMID:16266834

Benedetti, Serena; Rinalducci, Sara; Benvenuti, Francesca; Francogli, Sonia; Pagliarani, Silvia; Giorgi, Luca; Micheloni, Mauro; D'Amici, Gian Maria; Zolla, Lello; Canestrari, Franco

2005-11-02

260

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

SciTech Connect

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

Matsunaga, T.; Izumida, H.

1984-01-01

261

Influence of cypermethrin and fenvalerate on a green alga and three cyanobacteria isolated from soil.  

PubMed

The effects of two pyrethroid insecticides, cypermethrin and fenvalerate, on a green alga (Scenedesmus bijugatus) and three species of cyanobacteria (Synechococcus elongatus, Nostoc linckia, and Phormidium tenue), all isolated from a black cotton soil, were studied using either cell number or chlorophyll a as toxicity criterion. All the four species were either unaffected or stimulated at 5 micrograms ml-1. Of the two insecticides, cypermethrin, at 10 to 50 micrograms ml-1, inhibited S. bijugatus while these concentrations stimulated or only slightly inhibited the growth of S. elongatus. There was a significant inhibition in the growth of S. bijugatus and stimulation in S. elongatus with 10 to 50 micrograms ml-1 fenvalerate. The growth of N. linckia was enhanced by both insecticides while P. tenue was significantly affected. PMID:3121278

Megharaj, M; Venkateswarlu, K; Rao, A S

1987-10-01

262

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

NASA Astrophysics Data System (ADS)

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

Ambe, Shizuko

1990-07-01

263

Transformation of the Green Alga Haematococcus pluvialis with a Phytoene Desaturase for Accelerated Astaxanthin Biosynthesis?  

PubMed Central

Astaxanthin is a high-value carotenoid which is used as a pigmentation source in fish aquaculture. Additionally, a beneficial role of astaxanthin as a food supplement for humans has been suggested. The unicellular alga Haematococcus pluvialis is a suitable biological source for astaxanthin production. In the context of the strong biotechnological relevance of H. pluvialis, we developed a genetic transformation protocol for metabolic engineering of this green alga. First, the gene coding for the carotenoid biosynthesis enzyme phytoene desaturase was isolated from H. pluvialis and modified by site-directed mutagenesis, changing the leucine codon at position 504 to an arginine codon. In an in vitro assay, the modified phytoene desaturase was still active in conversion of phytoene to ?-carotene and exhibited 43-fold-higher resistance to the bleaching herbicide norflurazon. Upon biolistic transformation using the modified phytoene desaturase gene as a reporter and selection with norflurazon, integration into the nuclear genome of H. pluvialis and phytoene desaturase gene and protein expression were demonstrated by Southern, Northern, and Western blotting, respectively, in 11 transformants. Some of the transformants had a higher carotenoid content in the green state, which correlated with increased nonphotochemical quenching. This measurement of chlorophyll fluorescence can be used as a screening procedure for stable transformants. Stress induction of astaxanthin biosynthesis by high light showed that there was accelerated accumulation of astaxanthin in one of the transformants compared to the accumulation in the wild type. Our results strongly indicate that the modified phytoene desaturase gene is a useful tool for genetic engineering of carotenoid biosynthesis in H. pluvialis.

Steinbrenner, Jens; Sandmann, Gerhard

2006-01-01

264

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

PubMed

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

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

2012-06-19

265

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

PubMed

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

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

1995-01-01

266

Novel Shuttle Markers for Nuclear Transformation of the Green Alga Chlamydomonas reinhardtii?  

PubMed Central

The green alga Chlamydomonas reinhardtii today is a premier model organism for the study of green algae and plants. Yet the efficient engineering of its nuclear genome requires development of new antibiotic resistance markers. We have recoded, based on codon usage in the nuclear genome, the AadA marker that has been used previously for chloroplast transformation. The recoded AadA gene, placed under the control of the HSP70A-RBCS2 hybrid promoter and preceded by the RbcS2 chloroplast-targeting peptide, can be integrated into the nuclear genome by electroporation, conferring resistance to spectinomycin and streptomycin. Transformation efficiency is markedly increased when vector sequences are completely eliminated from the transforming DNA. Antibiotic resistance is stable for several months in the absence of selection pressure. Shuttle markers allowing selection in both Chlamydomonas and Escherichia coli would also be a useful asset. By placing an artificial bacterial promoter and Shine-Dalgarno sequence in frame within the AadA coding sequence, we generated such a shuttle marker. To our surprise, we found that the classical AphVIII construct already functions as a shuttle marker. Finally, we developed a method to introduce the AadA and AphVIII markers into the vector part of the bacterial artificial chromosomes (BACs) of the Chlamydomonas genomic DNA library. Our aim was to facilitate complementation studies whenever the test gene cannot be selected for directly. After transformation of a petC mutant with a modified BAC carrying the AphVIII marker along with the PETC gene in the insert, almost half of the paromomycin-resistant transformants obtained showed restoration of phototrophy, indicating successful integration of the unselected test gene. With AadA, cotransformation was also observed, but with a lower efficiency.

Meslet-Cladiere, Laurence; Vallon, Olivier

2011-01-01

267

Blue- and green-light signals for gamete release in the brown alga, Silvetia compressa.  

PubMed

The intertidal brown alga Silvetia compressa releases gametes from receptacles (the reproductive tissue) rapidly upon a dark transfer (following a photosynthesis-dependent period in the light, termed potentiation). In this study, the wavelength-dependence of this process was investigated. During the potentiation period in white light (WL), gametes are not released. However, gametes were released during potentiation in blue light (BL), or in low red light/blue light (RL/BL) ratios, but not in RL alone, high RL/BL ratios, or in broadband blue-green light (B-GL) (presence of BL, but absence of RL). RL was as effective as WL for potentiation, i.e., both lead to gamete release following transfer to darkness. Rates of linear photosynthetic electron transport were similar in RL and BL. Gamete release in BL was inhibited by equal amounts of additional narrow-waveband light between the green and red regions of the spectrum, with light-induced gamete release restricted between <491 nm and 509 nm. Very little light-induced gamete release occurred between 530 nm and 650 nm. It is proposed that a BL-responsive photoreceptor is responsible for light-induced gamete release. Transfer of WL-potentiated receptacles to GL near 530 nm resulted in significant de-potentiation and reduced gamete release during a subsequent dark transfer. This effect was not seen at 509 nm or 560 nm and revealed the presence of a second photoreceptor system repressing or counteracting potentiation in the light. We propose that the restriction of gamete release to periods when irradiance is blue-shifted may constitute a depth-sensing mechanism for this intertidal alga, allowing controlled release of gametes at high tide and/or less turbid periods, thus minimizing gamete dilution, and promoting fertilization success. PMID:14605987

Pearson, Gareth A; Serrão, Ester A; Dring, Matthew; Schmid, Rainer

2003-11-05

268

Evidence for HCO3? Transport by the Blue-Green Alga (Cyanobacterium) Coccochloris peniocystis1  

PubMed Central

The possibility of HCO3? transport in the blue-green alga (cyanobacterium) Coccochloris peniocystis has been investigated. Coccochloris photosynthesized most rapidly in the pH range 8 to 10, where most of the inorganic C exists as HCO3?. If photosynthesis used only CO2 from the external solution the rate of photosynthesis would be limited by the rate of HCO3? dehydration to CO2. Observed rates of photosynthesis at alkaline pH were as much as 48-fold higher than could be supported by spontaneous dehydration of HCO3? in the external solution. Assays for extracellular carbonic anhydrase were negative. The evidence strongly suggests that HCO3? was a direct C source for photosynthesis. Weakly buffered solutions became alkaline during photosynthesis with a one-to-one stoichiometry between OH? appearance in the medium and HCO3? initially added. Alkalization occurred only during photosynthesis and was blocked by 3-(3,4-dichlorophenyl)-1, 1-dimethylurea, diuron. It is suggested that HCO3? was transported into cells of Coccochloris in exchange for OH? produced as a result of HCO3? fixation in photosynthesis. The inorganic C concentration required to support a rate of photosynthesis of half the maximum rate (Km) was 6 micromolar at pH 8.0 or, in terms of available CO2, a Km of 0.16 micromolar. This value is two orders of magnitude lower than reported Km values for the d-ribulose-1,5-bisphosphate carboxylase for blue-green algae. It is suggested that the putative HCO3? transport by Coccochloris serves to raise the CO2 concentration around the carboxylase to levels high enough for effective fixation.

Miller, Anthony G.; Colman, Brian

1980-01-01

269

Novel shuttle markers for nuclear transformation of the green alga Chlamydomonas reinhardtii.  

PubMed

The green alga Chlamydomonas reinhardtii today is a premier model organism for the study of green algae and plants. Yet the efficient engineering of its nuclear genome requires development of new antibiotic resistance markers. We have recoded, based on codon usage in the nuclear genome, the AadA marker that has been used previously for chloroplast transformation. The recoded AadA gene, placed under the control of the HSP70A-RBCS2 hybrid promoter and preceded by the RbcS2 chloroplast-targeting peptide, can be integrated into the nuclear genome by electroporation, conferring resistance to spectinomycin and streptomycin. Transformation efficiency is markedly increased when vector sequences are completely eliminated from the transforming DNA. Antibiotic resistance is stable for several months in the absence of selection pressure. Shuttle markers allowing selection in both Chlamydomonas and Escherichia coli would also be a useful asset. By placing an artificial bacterial promoter and Shine-Dalgarno sequence in frame within the AadA coding sequence, we generated such a shuttle marker. To our surprise, we found that the classical AphVIII construct already functions as a shuttle marker. Finally, we developed a method to introduce the AadA and AphVIII markers into the vector part of the bacterial artificial chromosomes (BACs) of the Chlamydomonas genomic DNA library. Our aim was to facilitate complementation studies whenever the test gene cannot be selected for directly. After transformation of a petC mutant with a modified BAC carrying the AphVIII marker along with the PETC gene in the insert, almost half of the paromomycin-resistant transformants obtained showed restoration of phototrophy, indicating successful integration of the unselected test gene. With AadA, cotransformation was also observed, but with a lower efficiency. PMID:22002656

Meslet-Cladière, Laurence; Vallon, Olivier

2011-10-14

270

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

2012-08-10

271

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...

272

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

PubMed Central

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

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

2011-01-01

273

Antinociceptive and anti-inflammatory activities of lectin from the marine green alga Caulerpa cupressoides.  

PubMed

The search for new compounds for controlling pain and inflammation, with minimal side effects has focused on marine algae. The aim of this work was to investigate the effect of the purified lectin from the green marine alga Caulerpa cupressoides (CcL) in classical models of nociception and inflammation. Male Swiss mice received i.v. CcL 30 min prior to receiving 0.8% acetic acid (10 ml/kg; i.p); 1% formalin (20 microl; s.c.) or were subjected to thermal stimuli. We observed that CcL (3, 9 or 27 mg/kg) significantly reduced the number of writhes induced by acetic acid by 37.2%; 53.5% and 86.0%, respectively. CcL (27 mg/kg) also reduced the second phase of the formalin test. However, CcL (27 mg/kg) did not present significant antinociceptive effects in the hot plate test, when compared to morphine, suggesting that its antinociceptive action occurs predominantly through a peripheral mechanism. The antinociceptive effects were abolished when CcL was pre-incubated with mucin (20mg/kg; i.v.). When CcL (9 mg/kg) was administered i.v. in Wistar rats 30 min before carrageenan administration, neutrophil counts were reduced by 65.9%. CcL also inhibited paw edema in all time intervals, especially at the third hour. Finally, CcL (9 mg/kg) administered i.v. in mice did not cause hepatic or renal alterations and did not affect body mass or macroscopy of the organs examined. In conclusion, CcL appears to have important antinociceptive and anti-inflammatory activities and could represent an important agent for future studies. PMID:20601179

Vanderlei, Edfranck Sousa Oliveira; Patoilo, Kharla Kharolyni Nobre Rabelo; Lima, Neiberg Alcântara; Lima, Ana Patrícia Souza; Rodrigues, José Ariévilo Gurgel; Silva, Luana Maria Castelo Melo; Lima, Maria Edna Pereira; Lima, Vilma; Benevides, Norma Maria Barros

2010-06-27

274

An extended corona attached to metaphase kinetochores of the green alga Oedogonium.  

PubMed

Mitotic cells of the green alga Oedogonium were treated with the anti-microtubule agent oryzalin (1.0-0.1 microM) for 5 to 10 min. Within 5 min treatment of living cells, metaphase spindles became spherical with disorganized chromosomes, and anaphase spindles collapsed. At lower concentrations, the effects were slower, and partial recovery was observed about 10 to 20 min after the drug was washed out. Following breakdown of the spindle, considerable disorganized activity detected by time-lapse continued within the nucleus, isolated from the cytoplasm by its intact nuclear membrane. Under the electron microscope, spindle microtubules (MTs) were absent in oryzalin-treated cells. Paired metaphase kinetochores displayed an array of fine filamentous material extended, usually straight, about 3 microns into the nucleoplasm. In cells recovering from oryzalin treatment, MTs became associated with kinetochores in the usual manner. However, this filamentous array, the "extended corona" (EC), was almost undetectable, even when the MTs were short and poorly organized. The EC is appreciably larger by metaphase than the corona of prophase chromosomes and so it may assemble during early mitosis. Fine filaments interspersed with kinetochore MTs have been described in carefully fixed cells of this alga (M.J. Schibler, J.D. Pickett-Heaps, Eur. J. Cell Biol. 22, 687-698 (1980)). The EC apparently represents a less organized form of this material remaining after its scaffold of MTs has been removed. These fibers appear involved in MT capture upon spindle recovery from anti-MT drugs. They could function during prometaphase and even anaphase movement along spindle MTs. PMID:8330628

Pickett-Heaps, J D; Carpenter, J

1993-04-01

275

Resonant interactions of diatomic molecules with intense laser fields: time-independent multi-channel Green function theory and application to experiment  

Microsoft Academic Search

The resonant interactions of diatomic molecules with UV and VUV intense laser radiation are investigated within an original non-perturbative approach of multi-channel nuclear wave functions and Green's functions. The interactions are considered in a quantum-electrodynamic picture where the laser field and molecule are treated as quantum objects. The presented theoretical approach is formulated as a multi-quantum technique to calculate analytically

Alexander I. Pegarkov

2000-01-01

276

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

277

Experimental evidence that evolutionary relatedness does not affect the ecological mechanisms of coexistence in freshwater green algae.  

PubMed

The coexistence of competing species depends on the balance between their fitness differences, which determine their competitive inequalities, and their niche differences, which stabilise their competitive interactions. Darwin proposed that evolution causes species' niches to diverge, but the influence of evolution on relative fitness differences, and the importance of both niche and fitness differences in determining coexistence have not yet been studied together. We tested whether the phylogenetic distances between species of green freshwater algae determined their abilities to coexist in a microcosm experiment. We found that niche differences were more important in explaining coexistence than relative fitness differences, and that phylogenetic distance had no effect on either coexistence or on the sizes of niche and fitness differences. These results were corroborated by an analysis of the frequency of the co-occurrence of 325 pairwise combinations of algal taxa in > 1100 lakes across North America. Phylogenetic distance may not explain the coexistence of freshwater green algae. PMID:24112458

Narwani, Anita; Alexandrou, Markos A; Oakley, Todd H; Carroll, Ian T; Cardinale, Bradley J

2013-09-23

278

Inhibition of the growth of micro-algae and bacteria by extracts of eelgrass ( Zostera marina ) leaves  

Microsoft Academic Search

The effects of the water-soluble fraction of dead leaves of the eelgrass Zostera marina L. on the growth of 8 species of micro-algae (pennate and centric diatoms, dinoflagellates, and a green flagellate) and a bacterium were studied on agar plates and in liquid culture. The extracts of leaves which had been dead from a few days to 2 wk inhibited

Paul G. Harrison; A. T. Chan

1980-01-01

279

Identification of two forms of PFK and a fructose-2,6-bisphosphate independent form of PFP in a green alga  

Microsoft Academic Search

Cell-free preparations from the green alga, Chlorella pyrenoidosa, contained two forms of phosphofructokinase (PFK), designated PFK I and PFK II. This represents the first evidence for a second form of PFK in green algae. A pyrophosphate D-fructose-6-phosphate, 1-phosphotransferase (PFP) activity, that was unaffected by the regulatory metabolite, fructose-2,6-bisphosphate, co-purified with PFK II through several steps. The data suggest that Chlorella

F. Kiss; T. C. Johnson; A. L. Klecan; Gy. Vincze; B. B. Buchanan; A. Balogh

1989-01-01

280

Up-Regulation of Photoprotection and PSII Repair Gene Expression by Irradiance in the Unicellular Green Alga Dunaliella salina  

Microsoft Academic Search

The unicellular green alga Dunaliella salina is an attractive model organism for studying photoacclimation responses and the photosystem II (PSII) damage and repair process\\u000a in the photosynthetic apparatus. Irradiance during cell growth defines both the photoacclimation and the PSII repair status\\u000a of the cells. To identify genes specific to these processes, a cDNA library was created from irradiance-stressed D. salina.

Juergen E. W. Polle; Anastasios Melis; Taek Kyun Lee; EonSeon Jin

2006-01-01

281

ELISA and LCMS\\/MS methods for determining cyanobacterial toxins in blue-green algae food supplements  

Microsoft Academic Search

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

M. Bruno; M. Fiori; D. Mattei; S. Melchiorre; V. Messineo; F. Volpi; S. Bogialli; M. Nazzari

2006-01-01

282

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

Microsoft Academic Search

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

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

1977-01-01

283

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

Microsoft Academic Search

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

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

1996-01-01

284

Comparative effects of Azolla and blue-green algae in combination with chemical N fertilizer on rice crop  

Microsoft Academic Search

FreshAzolla pinnata (Bangkok) and dry blue-green algae dominated byAulosira sp. andGloeotrichia sp. were inoculated separately at the rates of 500 and 10 kg\\/ha, 10 and 3 days after transplanting, respectively to evaluate\\u000a their effects in combination with chemical N fertilizer applied at different stages of rice crop. Split application of 30\\u000a kg N\\/ha urea (15 kg basal and 15 kg

A L Singh; P K Singh

1986-01-01

285

The flanking regions of PsaD drive efficient gene expression in the nucleus of the green alga Chlamydomonas reinhardtii  

Microsoft Academic Search

The nuclear gene PsaD encodes an abundant chloroplast protein located on the stromal side of the Photosystem I complex. We have cloned and sequenced a genomic fragment containing the PsaD gene from the green alga Chlamydomonas reinhardtii. Sequence comparison with its cDNA revealed that the PsaD ORF contains no introns. Thus, the regulatory sequences required for high-level expression of PsaD

N. Fischer; J.-D. Rochaix

2001-01-01

286

Analysis of the promoter region in the rrnA operon from a blue-green alga, Anacystis nidulans 6301  

Microsoft Academic Search

The nucleotide sequence has been determined of a 1431 base pair (bp) region upstream from the 16S rRNA gene in the rrnA operon of a blue-green alga, Anacystis nidulans 6301. The transcriptional initiation site has been identified by S1 mapping with in vivo RNAs and in vitro transcripts synthesized by A. nidulans RNA polymerase. The initiation site is located 186

Masanobu Kumano; Noboru Tomioka; Kazuo Shinozaki; Masahiro Sugiura

1986-01-01

287

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

288

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

289

QSAR analysis and specific endpoints for classifying the physiological modes of action of biocides in synchronous green algae  

Microsoft Academic Search

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

Judith Neuwoehner; Marion Junghans; Mirjam Koller; Beate I. Escher

2008-01-01

290

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

291

Characterization of Photosystem II Activity and Heterogeneity during the Cell Cycle of the Green Alga Scenedesmus quadricauda  

Microsoft Academic Search

The photosynthetic activity of the green alga Scenedesmus quad- ricauda was investigated during synchronous growth in light\\/dark cycles. The rate of O2 evolution increased 2-fold during the first 3 to 4ho f thelight period, remained high for the next 3 to 4 h, and then declined during the last half of the light period. During cell division, which occurred at

David Kaftan; Tibor Meszaros; John Whitmarsh; Ladislav Nedbal

1999-01-01

292

Effects of pH and selected metals on growth of the filamentous green alga Mougeotia under acidic conditions  

Microsoft Academic Search

When acid precipitation impacts freshwater systems, littoral blooms of the filamentous green alga Mougeotia (Zygnematales, Charophyceae) frequently develop. Field observations of its development in Little Rock Lake, an experimentally acidified seepage lake in north-central Wisconsin, indicated that the species of Mougeotia present there may have an optimum pH for growth of -5.2. Because a number of metals increase in concentration

James M. Graham; Patricia Arancibia-Avila; Linda E. Graham

1996-01-01

293

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

Microsoft Academic Search

Between 1991 and 1993, Saginaw Bay experienced an invasion by zebra mussels, Dreissena polymorpha, which caused a significant perturbation to the ecosystem. Blooms of Microcystis, a toxin-producing blue-green alga, became re-established in the bay after the zebra mussel invasion. Microcystis blooms had all but been eliminated in the early 1980s with controls on external phosphorus loadings, but have re-occurred in

Victor J. Bierman Jr.; Jagjit Kaur; Joseph V. Depinto; Timothy J. Feist; David W. Dilks

2005-01-01

294

Metabolic Flexibility of the Green Alga Chlamydomonas reinhardtii as Revealed by the Link between State Transitions and Cyclic Electron Flow  

Microsoft Academic Search

In this Review we focus on the conversion of linear photosynthetic electron transport from water to NADP to the cyclic pathway\\u000a around Photosystem I in the green alga Chlamydomonas reinhardtii. We discuss the strict relationship that exists between the changes in pathways of electron transport and state transitions,\\u000a i.e., the reversible functional association of light harvesting proteins with one of

Giovanni Finazzi; Giorgio Forti

2004-01-01

295

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

296

Molecular Identification of Rickettsial Endosymbionts in the Non-Phagotrophic Volvocalean Green Algae  

PubMed Central

Background The order Rickettsiales comprises Gram-negative obligate intracellular bacteria (also called rickettsias) that are mainly associated with arthropod hosts. This group is medically important because it contains human-pathogenic species that cause dangerous diseases. Until now, there has been no report of non-phagotrophic photosynthetic eukaryotes, such as green plants, harboring rickettsias. Methodology/Principal Findings We examined the bacterial endosymbionts of two freshwater volvocalean green algae: unicellular Carteria cerasiformis and colonial Pleodorina japonica. Epifluorescence microscopy using 4?-6-deamidino-2-phenylindole staining revealed the presence of endosymbionts in all C. cerasiformis NIES-425 cells, and demonstrated a positive correlation between host cell size and the number of endosymbionts. Strains both containing and lacking endosymbionts of C. cerasiformis (NIES-425 and NIES-424) showed a >10-fold increase in cell number and typical sigmoid growth curves over 192 h. A phylogenetic analysis of 16 S ribosomal (r)RNA gene sequences from the endosymbionts of C. cerasiformis and P. japonica demonstrated that they formed a robust clade (hydra group) with endosymbionts of various non-arthropod hosts within the family Rickettsiaceae. There were significantly fewer differences in the 16 S rRNA sequences of the rickettsiacean endosymbionts between C. cerasiformis and P. japonica than in the chloroplast 16 S rRNA or 18 S rRNA of the host volvocalean cells. Fluorescence in situ hybridization demonstrated the existence of the rickettsiacean endosymbionts in the cytoplasm of two volvocalean species. Conclusions/Significance The rickettsiacean endosymbionts are likely not harmful to their volvocalean hosts and may have been recently transmitted from other non-arthropod organisms. Because rickettsias are the closest relatives of mitochondria, incipient stages of mitochondrial endosymbiosis may be deduced using both strains with and without C. cerasiformis endosymbionts.

Kawafune, Kaoru; Hongoh, Yuichi; Hamaji, Takashi; Nozaki, Hisayoshi

2012-01-01

297

In vivo localization of centrin in the green alga Chlamydomonas reinhardtii.  

PubMed

The green alga Chlamydomonas reinhardtii has been used as a model system to study flagellar assembly, centriole assembly, and cell cycle events. These processes are dynamic. Therefore, protein targeting and protein-protein interactions should be evaluated in vivo. To be able to study dynamic processes in C. reinhardtii in vivo, we have explored the use of the green fluorescent protein (GFP). A construct containing a fusion of centrin and GFP was incorporated into the genome as a single copy. The selected clone shows expression in 25-50% of the cells. Centrin-GFP was targeted in vivo to the nuclear basal body connectors and the distal connecting fibers. At the electron microscopic level, it was also localized to the flagellar transitional regions. EM data of transformants indicate that there are some abnormalities in the centrin-containing structures. The transitional region consists of only the transverse septum or has lesions in the H-piece. The distal connecting fibers are thinner and their characteristic crossbands seem to be incomplete. Deflagellation is not affected since more than 95% of the cells deflagellate. Also basal body segregation is not affected since cells with an abnormal flagellar number were not detected. Functional studies of the centrin-GFP fusion show the characteristic calcium-induced mobility shift in SDS-PAGE. Immunofluorescence revealed that during cell division, centrin-GFP remains associated with the basal bodies. In vivo localization of the fusion protein during cell division shows that in metaphase centrin-GFP appears as two opposing spots located close to the spindle poles. The distance between the spots increases as the cells progress through anaphase and then decreases during telophase. GFP is a useful tool to study dynamic processes in the cytoskeleton of C. reinhardtii. PMID:11977082

Ruiz-Binder, Nayma E; Geimer, Stefan; Melkonian, Michael

2002-05-01

298

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

PubMed Central

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

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

2012-01-01

299

Arabitol provided by lichenous fungi enhances ability to dissipate excess light energy in a symbiotic green alga under desiccation.  

PubMed

Lichens are drought-resistant symbiotic organisms of mycobiont fungi and photobiont green algae or cyanobacteria, and have an efficient mechanism to dissipate excess captured light energy into heat in a picosecond time range to avoid photoinhibition. This mechanism can be assessed as drought-induced non-photochemical quenching (d-NPQ) using time-resolved fluorescence spectroscopy. A green alga Trebouxia sp., which lives within a lichen Ramalina yasudae, is one of the most common green algal photobionts. This alga showed very efficient d-NPQ under desiccation within the lichen thallus, whereas it lost d-NPQ ability when isolated from R. yasudae, indicating the importance of the interaction with the mycobiont for d-NPQ ability. We analyzed the water extracts from lichen thalli that enhanced d-NPQ in Trebouxia. Of several sugar compounds identified in the water extracts by nuclear magnetic resonance (NMR), mass spectrometry (MS) and gas chromatography (GC) analyses, only d-arabitol recovered d-NPQ in isolated Trebouxia to a level similar to that detected for R. yasudae thallus. Other sugar compounds did not help the expression of d-NPQ at the same concentrations. Thus, arabitol is essential for the expression of d-NPQ to dissipate excess captured light energy into heat, protecting the photobiont from photoinhibition. The relationship between mycobionts and photobionts is, therefore, not commensalism, but mutualism with each other, as shown by d-NPQ expression. PMID:23737501

Kosugi, Makiko; Miyake, Hirohisa; Yamakawa, Hisanori; Shibata, Yutaka; Miyazawa, Atsuo; Sugimura, Takashi; Satoh, Kazuhiko; Itoh, Shigeru; Kashino, Yasuhiro

2013-06-03

300

Investigation into the Optical Properties of Nanostructured Silica from Diatoms.  

National Technical Information Service (NTIS)

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

M. Hildebrand B. Palenik

2003-01-01

301

Removal of malachite green by using an invasive marine alga Caulerpa racemosa var. cylindracea.  

PubMed

The biosorption of a cationic dye, malachite green oxalate (MG) from aqueous solution onto an invasive marine alga Caulerpa racemosa var. cylindracea (CRC) was investigated at different temperatures (298, 308 and 318 K). The dye adsorption onto CRC was confirmed by FTIR analysis. Equilibrium data were analyzed using Freundlich, Langmuir and Dubinin-Radushkevich (DR) equations. All of the isotherm parameters were calculated. The Freundlich model gave a better conformity than Langmuir equation. The mean free energy values (E) from DR isotherm were also estimated. In order to clarify the sorption kinetic, the fit of pseudo-first-order kinetic model, second-order kinetic model and intraparticle diffusion model were investigated. It was obtained that the biosorption process followed the pseudo-second-order rate kinetics. From thermodynamic studies the free energy changes were found to be -7.078, -9.848 and -10.864 kJ mol(-1) for 298, 308 and 318 K, respectively. This implied the spontaneous nature of biosorption and the type of adsorption as physisorption. Activation energy value for MG sorption (E(a)) was found to be 37.14 kJ mol(-1). It could be also derived that this result supported physisorption as a type of adsorption. PMID:18562093

Bekçi, Zehra; Seki, Yolda?; Cavas, Levent

2008-05-07

302

Bioenergetic strategy for the biodegradation of p-cresol by the unicellular green alga Scenedesmus obliquus.  

PubMed

Cultures from the unicellular green alga Scenedesmus obliquus biodegrade the toxic p-cresol (4-methylphenol) and use it as alternative carbon/energy source. The biodegradation procedure of p-cresol seems to be a two-step process. HPLC analyses indicate that the split of the methyl group (first step) that is possibly converted to methanol (increased methanol concentration in the growth medium), leading, according to our previous work, to changes in the molecular structure and function of the photosynthetic apparatus and therefore to microalgal biomass increase. The second step is the fission of the intermediately produced phenol. A higher p-cresol concentration results in a higher p-cresol biodegradation rate and a lower total p-cresol biodegradability. The first biodegradation step seems to be the most decisive for the effectiveness of the process, because methanol offers energy for the further biodegradation reactions. The absence of LHCII from the Scenedesmus mutant wt-lhc stopped the methanol effect and significantly reduced the p-cresol biodegradation (only 9%). The present contribution deals with an energy distribution between microalgal growth and p-cresol biodegradation, activated by p-cresol concentration. The simultaneous biomass increase with the detoxification of a toxic phenolic compound (p-cresol) could be a significant biotechnological aspect for further applications. PMID:23251641

Papazi, Aikaterini; Assimakopoulos, Konstantinos; Kotzabasis, Kiriakos

2012-12-14

303

Are carbon nanotube effects on green algae caused by shading and agglomeration?  

PubMed

Due to growing production, carbon nanotubes (CNT) may soon be found in a broad range of products and thus in the environment. In this work, an algal growth test was developed to determine effects of pristine and oxidized CNT on the green algae Chlorella vulgaris and Pseudokirchneriella subcapitata. CNT suspensions were prepared in algal test medium and characterized taking into account the suspension age, the reduced light transmittance of nanoparticle suspensions defined as shading of CNT and quantified by UV/vis spectroscopy, and the agglomeration of the CNT and of the algal cells. Growth inhibition and photosynthetic activity were investigated as end points. Growth of C. vulgaris was inhibited with effect concentrations of 50% (EC(50)) values of 1.8 mg CNT/L and of 24 mg CNT/L in well dispersed and in agglomerated suspensions, respectively, and 20 mg CNT/L and 36 mg CNT/L for P. subcapitata, respectively. However, the photosynthetic activity was not affected. Growth inhibition was highly correlated with the shading of CNT and the agglomeration of algal cells. This suggests that the reduced algal growth might be caused mainly by indirect effects, i.e. by reduced availability of light and different growth conditions caused by the locally elevated algal concentration inside of CNT agglomerates. PMID:21702508

Schwab, Fabienne; Bucheli, Thomas D; Lukhele, Lungile P; Magrez, Arnaud; Nowack, Bernd; Sigg, Laura; Knauer, Katja

2011-06-27

304

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

PubMed Central

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

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

1974-01-01

305

Isolation of Prasinoviruses of the Green Unicellular Algae Ostreococcus spp. on a Worldwide Geographical Scale? †  

PubMed Central

Ostreococcus spp. are extremely small unicellular eukaryotic green algae found worldwide in marine environments, and they are susceptible to attacks by a diverse group of large DNA viruses. Several biologically distinct species of Ostreococcus are known and differ in the ecological niches that they occupy: while O. tauri (representing clade C strains) is found in marine lagoons and coastal seas, strains belonging to clade A, exemplified by O. lucimarinus, are present in different oceans. We used laboratory cultures of clonal isolates of these two species to assay for the presence of viruses in seawater samples from diverse locations. In keeping with the distributions of their host strains, we found a decline in the abundance of O. tauri viruses from a lagoon in southwest France relative to the Mediterranean Sea, whereas in the ocean, no O. tauri viruses were detected. In contrast, viruses infecting O. lucimarinus were detected from distantly separated oceans. DNA sequencing, phylogenetic analyses using a conserved viral marker gene, and a Mantel test revealed no relationship between geographic and phylogenetic distances in viruses infecting O. lucimarinus.

Bellec, Laure; Grimsley, Nigel; Desdevises, Yves

2010-01-01

306

Monophyly of primary photosynthetic eukaryotes: green plants, red algae, and glaucophytes.  

PubMed

Between 1 and 1.5 billion years ago, eukaryotic organisms acquired the ability to convert light into chemical energy through endosymbiosis with a Cyanobacterium (e.g.,). This event gave rise to "primary" plastids, which are present in green plants, red algae, and glaucophytes ("Plantae" sensu Cavalier-Smith). The widely accepted view that primary plastids arose only once implies two predictions: (1) all plastids form a monophyletic group, as do (2) primary photosynthetic eukaryotes. Nonetheless, unequivocal support for both predictions is lacking (e.g.,). In this report, we present two phylogenomic analyses, with 50 genes from 16 plastid and 15 cyanobacterial genomes and with 143 nuclear genes from 34 eukaryotic species, respectively. The nuclear dataset includes new sequences from glaucophytes, the less-studied group of primary photosynthetic eukaryotes. We find significant support for both predictions. Taken together, our analyses provide the first strong support for a single endosymbiotic event that gave rise to primary photosynthetic eukaryotes, the Plantae. Because our dataset does not cover the entire eukaryotic diversity (but only four of six major groups in), further testing of the monophyly of Plantae should include representatives from eukaryotic lineages for which currently insufficient sequence information is available. PMID:16051178

Rodríguez-Ezpeleta, Naiara; Brinkmann, Henner; Burey, Suzanne C; Roure, Béatrice; Burger, Gertraud; Löffelhardt, Wolfgang; Bohnert, Hans J; Philippe, Hervé; Lang, B Franz

2005-07-26

307

Polaribacter reichenbachii sp. nov.: a new marine bacterium associated with the green alga Ulva fenestrata.  

PubMed

A Gram-negative, aerobic, rod-shaped, motile by gliding and yellow-pigmented bacterium, designated strain 6Alg 8(T), was isolated from the common Pacific green alga Ulva fenestrata. The phylogenetic analysis based on 16S rRNA gene sequence placed the novel strain within the genus Polaribacter, a member of the family Flavobacteriaceae, the phylum Bacteroidetes, with sequence similarities of 97.6 % to Polaribacter dokdonensis DSW-5(T) and 92.8-96.1 % to other recognized Polaribacter species. The prevalent fatty acids of strain 6Alg 8(T) were iso-C(15:0), iso-C(15:1), iso-C(15:0) 2-OH, C(15:0) and C(15:1)?6. The polar lipid profile consisted of the major lipids phosphatidylethanolamine, two unknown aminolipids and one unknown lipid. The DNA G+C content of the type strain is 31.6 mol%. The new isolate and the type strains of recognized species of the genus Polaribacter were readily distinguished based on a number of phenotypic characteristics. A combination of the genotypic and phenotypic data showed that the algal isolate represents a novel species of the genus Polaribacter, for which the name Polaribacter reichenbachii sp. nov. is proposed. The type strain is 6Alg 8(T) (= KCTC 23969(T) = KMM 6386(T) = LMG 26443(T)). PMID:23053482

Nedashkovskaya, Olga I; Kukhlevskiy, Andrey D; Zhukova, Natalia V

2012-09-28

308

Regulation of Phosphoenolpyruvate Carboxylase from the Green Alga Selenastrum minutum1  

PubMed Central

Two isoforms of phosphoenolpyruvate carboxylase (PEPC) with very different regulatory properties were partially purified from the green alga Selenastrum minutum. They were designated PEPC1 and PEPC2. PEPC1 showed sigmoidal kinetics with respect to phosphoenolpyruvate (PEP) whereas PEPC2 exhibited a typical Michaelis-Menten response. The S0.5(PEP) of PEPC1 was 2.23 millimolar. This was fourfold greater than the S0.5(PEP) of PEPC2, which was 0.57 millimolar. PEPC1 was activated more than fourfold by 2.0 millimolar glutamine and sixfold by 2.0 millimolar dihydroxyacetone phosphate (DHAP) at a subsaturating PEP concentration of 0.625 millimolar. In contrast, PEPC2 showed only 8% and 52% activation by glutamine and DHAP, respectively. The effects of glutamine and DHAP were additive. PEPC1 was more sensitive to inhibition by glutamate, 2-oxoglutarate, and aspartate than PEPC2. Both isoforms were equally inhibited by malate. All of these metabolites affected only the S0.5(PEP) not the Vmax. The regulatory properties of S. minutum PEPC in vitro are discussed in terms of (a) increased rates of dark carbon fixation (shown to be catalyzed predominantly by PEPC) and (b) changes in metabolite levels in vivo during enhanced NH4+ assimilation. Finally, a model is proposed for the regulation of PEPC in vivo in relation to its role in replenishing tricarboxylic acid cycle intermediates consumed in NH4+ assimilation.

Schuller, Kathryn A.; Plaxton, William C.; Turpin, David H.

1990-01-01

309

Gene replacement by homologous recombination in the multicellular green alga Volvox?carteri  

PubMed Central

With only two different cell types, the haploid green alga Volvox represents the simplest multicellular model system. To facilitate genetic investigations in this organism, the occurrence of homologous recombination events was investigated with the intent of developing methods for gene replacement and gene disruption. First, homologous recombination between two plasmids was demonstrated by using overlapping nonfunctional fragments of a recombinant arylsulfatase gene (tubulin promoter/arylsulfatase gene). After bombardment of Volvox reproductive cells with DNA-coated gold microprojectiles, transformants expressing arylsulfatase constitutively were recovered, indicating the presence of the machinery for homologous recombination in Volvox. Second, a well characterized loss-of-function mutation in the nuclear nitrate reductase gene (nitA) with a single G ? A nucleotide exchange in a 5?-splice site was chosen as a target for gene replacement. Gene replacement by homologous recombination was observed with a reasonably high frequency only if the replacement vector containing parts of the functional nitrate reductase gene contained only a few nucleotide exchanges. The ratio of homologous to random integration events ranged between 1:10 and 1:50, i.e., homologous recombination occurs frequently enough in Volvox to apply the powerful tool of gene disruption for functional studies of novel genes.

Hallmann, Armin; Rappel, Annette; Sumper, Manfred

1997-01-01

310

Flow cytometric determination of the photoinduced toxicity of anthracene to the green alga selenastrum capricornutum  

SciTech Connect

Certain PAHs are photosensitizers and in the presence of solar radiation can cause toxicity to aquatic plants and animals. The photoinduced toxicity of anthracene to the green alga Selenastrum capricornutum was assessed by the use of flow cytometry to measure cell size, cellular chlorophyll concentration, and cell viability. Anthracene was slightly toxic in the absence of UV-A radiation. The detection of the direct toxicity of anthracene in this study at a concentration of 19 [mu]g/L anthracene resulted from the use of sensitive flow cytometric measures. There was a significant interaction between anthracene and UV-A radiation, which, in combination, caused significant toxic effects on Selenastrum capricornutum. The most sensitive flow cytometric measure of toxicity was the stress index (SI), which was predictive of longer term effects on cell growth. The 28-h EC50 and EC10 and for the SI for Selenastrum capricornutum were 16.1 and 8.3 [mu]g/L anthracene, respectively, at 125 [mu]W/cm[sup 2] UV-A. All combinations for anthracene and UV-A that inhibited algal growth also caused a significantly greater number of nonviable cells. The flow cytometric methods used in this study proved to be sensitive, predictive measures of the direct and photo-induced toxicity of anthracene and UV-A radiation to Selenastrum capricornutum.

Gala, W.R.; Giesy, J.P. (Michigan State Univ., East Lansing, MI (United States). Dept. of Fisheries and Wildlife)

1994-05-01

311

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.

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

1994-01-01

312

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

PubMed

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.

1994-02-01

313

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

PubMed

A surface plasmon resonance (SPR) immunobiosensor assay was developed and validated to detect microcystin toxins in Spirulina and Aphanizomenon flos-aquae blue-green algae (BGA) food supplements. A competitive inhibition SPR-biosensor was developed using a monoclonal antibody to detect microcystin (MC) toxins. Powdered BGA samples were extracted with an aqueous methanolic solution, centrifuged and diluted in HBS-EP buffer prior to analysis. The assay was validated in accordance with the performance criteria outlined in EU legislation 2002/657/EC. The limit of detection (LOD) of the assay was calculated from the analysis of 20 known negative BGA samples to be 0.561 mg kg(-1). The detection capability (CC?) of the assay was determined to be ? 0.85 mg kg(-1) for MC-LR. The biosensor assay was successfully applied to detect MC-LR toxins in BGA samples purchased on the Irish retail market. MC-LR was detected in samples at levels ranging from <0.5 to 2.21 mg kg(-1). The biosensor results were in good agreement with an established LC-MS/MS assay. The assay is advantageous because it employs a simple clean-up procedure compared to chemical assays and allows automated unattended analysis of samples unlike ELISA. PMID:21482261

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

2011-01-22

314

[Phototaxis of the green algae: the new class of rhodopsin receptors].  

PubMed

Photomotility behavior in green flagellate algae is mediated by rhodopsin-like receptors, which was initially suggested on the basis of physiological evidence. The cascade of rapid Ca(2+)-dependent electrical responses in the plasma membrane plays a key role in the signal transduction chain during both phototaxis and the photophobic response. The photoreceptor current through the plasma membrane is the earliest detectable event upon photoexcitation of the photoreceptors. Analysis of this current revealed that it consists of at least two components with different characteristics. Genes encoding two archaeal-type rhodopsins (type I rhodopsins) were recently identified in the genome of Chlamydomonas reinhardtii and named (Chlamydomonas Sensory Rhodopsins A and B CSRA and CSRB). The measurements of photoelectric and motor responses in genetic transformants of C. reinhardtii enriched in each of these receptor proteins showed that the two components of the photoreceptor current are mediated by the two rhodopsins, and that both CSRA and CSRB are involved in phototaxis and the photophobic response. The CSRA-mediated current dominates at high light intensities and contributes primarily to the photophobic response. The CSRB-initiated transduction involves an efficient amplification cascade and mediates the highly sensitive phototaxis at low light intensities. CSRA and CSRB expressed heterologously in oocytes of Xenopus laevis act as light-gated proton channels, although it is unclear whether this channel activity plays a functional role in the initiation of motor responses and/or occurs in the native system. PMID:15129628

Govorunova, E G; Jung, K H; Sineshchekov, O A

315

Ammonia removal from anaerobic digestion effluent of livestock waste using green alga Scenedesmus sp.  

PubMed

The green alga Scenedesmus was investigated for its ability to remove nitrogen from anaerobic digestion effluent possessing high ammonium content and alkalinity in addition to its growth characteristics. Nitrate and ammonium were indistinguishable as a nitrogen source when the ammonium concentration was at normal cultivation levels. Ammonium up to 100ppm NH(4)-N did not inhibit cell growth, but did decrease final cell density by up to 70% at a concentration of 200-500ppm NH(4)-N. Inorganic carbon of alkalinity in the form of bicarbonate was consumed rapidly, in turn causing the attenuation of cell growth. Therefore, maintaining a certain level of inorganic carbon is necessary in order to prolong ammonia removal. A moderate degree of aeration was beneficial to ammonia removal, not only due to the stripping of ammonium to ammonia gas but also due to the stripping of oxygen, which is an inhibitor of regular photosynthesis. Magnesium is easily consumed compared to other metallic components and therefore requires periodic supplementation. Maintaining appropriate levels of alkalinity, Mg, aeration along with optimal an initial NH(4)(+)/cell ratio were all necessary for long-term semi-continuous ammonium removal and cell growth. PMID:20663665

Park, Jongmin; Jin, Hai-Feng; Lim, Byung-Ran; Park, Ki-Young; Lee, Kisay

2010-11-01

316

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

PubMed Central

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

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

2013-01-01

317

Transcriptome for photobiological hydrogen production induced by sulfur deprivation in the green alga Chlamydomonas reinhardtii.  

PubMed

Photobiological hydrogen production using microalgae is being developed into a promising clean fuel stream for the future. In this study, microarray analyses were used to obtain global expression profiles of mRNA abundance in the green alga Chlamydomonas reinhardtii at different time points before the onset and during the course of sulfur-depleted hydrogen production. These studies were followed by real-time quantitative reverse transcription-PCR and protein analyses. The present work provides new insights into photosynthesis, sulfur acquisition strategies, and carbon metabolism-related gene expression during sulfur-induced hydrogen production. A general trend toward repression of transcripts encoding photosynthetic genes was observed. In contrast to all other LHCBM genes, the abundance of the LHCBM9 transcript (encoding a major light-harvesting polypeptide) and its protein was strongly elevated throughout the experiment. This suggests a major remodeling of the photosystem II light-harvesting complex as well as an important function of LHCBM9 under sulfur starvation and photobiological hydrogen production. This paper presents the first global transcriptional analysis of C. reinhardtii before, during, and after photobiological hydrogen production under sulfur deprivation. PMID:18708561

Nguyen, Anh Vu; Thomas-Hall, Skye R; Malnoë, Alizée; Timmins, Matthew; Mussgnug, Jan H; Rupprecht, Jens; Kruse, Olaf; Hankamer, Ben; Schenk, Peer M

2008-08-15

318

Salt stress-induced cell death in the unicellular green alga Micrasterias denticulata.  

PubMed

Programmed cell death (PCD) is a key element in normal plant growth and development which may also be induced by various abiotic and biotic stress factors including salt stress. In the present study, morphological, biochemical, and physiological responses of the theoretically immortal unicellular freshwater green alga Micrasterias denticulata were examined after salt (200 mM NaCl or 200 mM KCl) and osmotic stress induced by iso-osmotic sorbitol. KCl caused morphological changes such as cytoplasmic vacuolization, extreme deformation of mitochondria, and ultrastructural changes of Golgi and ER. However, prolonged salt stress (24 h) led to the degradation of organelles by autophagy, a special form of PCD, both in NaCl- and KCl-treated cells. This was indicated by the enclosure of organelles by ER-derived double membranes. DNA of NaCl- and KCl-stressed cells but not of sorbitol-treated cells showed a ladder-like pattern on agarose gel, which means that the ionic rather than the osmotic component of salt stress leads to the activation of the responsible endonuclease. DNA laddering during salt stress could be abrogated by addition of Zn(2+). Neither cytochrome c release from mitochondria nor increase in caspase-3-like activity occurred after salt stress. Reactive oxygen species could be detected within 5 min after the onset of salt and osmotic stress. Respiration, photosynthetic activity, and pigment composition indicated an active metabolism which supports programmed rather than necrotic cell death in Micrasterias after salt stress. PMID:19213813

Affenzeller, Matthias Josef; Darehshouri, Anza; Andosch, Ancuela; Lütz, Cornelius; Lütz-Meindl, Ursula

2009-02-12

319

Nitric oxide suppresses growth and development in the unicellular green alga Micrasterias denticulata.  

PubMed

Nitric oxide (NO), a key molecule in inter- and intracellular signalling, is implicated in developmental processes, host defense, and apoptosis in higher plants. We investigated the effect of NO on development in the unicellular green alga, Micrasterias denticulata, using two different NO donors, S-nitroso-N-acetyl-dl-penicillamine (SNAP) and sodium nitroprusside (SNP). Investigations at the light microsopic level revealed that both NO donors suppressed cell growth. Ultrastructural analyses were performed with SNAP- as well as SNP-treated cells and, additionally, with the control compound N-acetyl-d-penicillamine (NAP). Cells incubated with NO donors lacked a secondary wall and dictyosomal function was impaired, whereas NAP-treated cells showed no difference in development and organelle structure compared to control cells. Moreover, cisternae of the Golgi stacks were slightly involute and no vesicles were pinched off after SNAP and SNP incubation. The NO scavenger cPTIO (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, potassium salt) abrogated the effect of SNP, thus confirming that inhibition of cell growth is due to nitric oxide. Addition of iodoacetic acid, an inhibitor of cysteine-containing enzymes, like glyceraldehyde-3-phosphate dehydrogenase (GAPDH), evoked similar effects on cell growth and secondary wall formation as obtained by treatment with NO donors. Therefore, we hypothesize that NO inhibits activity of enzymes involved in the secretory pathway, such as GAPDH, via S-nitrosylation of the cysteine residue and, consequently, modulates cell growth in M. denticulata. PMID:18455833

Lehner, Christine; Kerschbaum, Hubert H; Lütz-Meindl, Ursula

2008-05-02

320

Salt stress-induced cell death in the unicellular green alga Micrasterias denticulata  

PubMed Central

Programmed cell death (PCD) is a key element in normal plant growth and development which may also be induced by various abiotic and biotic stress factors including salt stress. In the present study, morphological, biochemical, and physiological responses of the theoretically immortal unicellular freshwater green alga Micrasterias denticulata were examined after salt (200 mM NaCl or 200 mM KCl) and osmotic stress induced by iso-osmotic sorbitol. KCl caused morphological changes such as cytoplasmic vacuolization, extreme deformation of mitochondria, and ultrastructural changes of Golgi and ER. However, prolonged salt stress (24 h) led to the degradation of organelles by autophagy, a special form of PCD, both in NaCl- and KCl-treated cells. This was indicated by the enclosure of organelles by ER-derived double membranes. DNA of NaCl- and KCl-stressed cells but not of sorbitol-treated cells showed a ladder-like pattern on agarose gel, which means that the ionic rather than the osmotic component of salt stress leads to the activation of the responsible endonuclease. DNA laddering during salt stress could be abrogated by addition of Zn2+. Neither cytochrome c release from mitochondria nor increase in caspase-3-like activity occurred after salt stress. Reactive oxygen species could be detected within 5 min after the onset of salt and osmotic stress. Respiration, photosynthetic activity, and pigment composition indicated an active metabolism which supports programmed rather than necrotic cell death in Micrasterias after salt stress.

Affenzeller, Matthias Josef; Darehshouri, Anza; Andosch, Ancuela; Lutz, Cornelius; Lutz-Meindl, Ursula

2009-01-01

321

Transcriptome for Photobiological Hydrogen Production Induced by Sulfur Deprivation in the Green Alga Chlamydomonas reinhardtii? †  

PubMed Central

Photobiological hydrogen production using microalgae is being developed into a promising clean fuel stream for the future. In this study, microarray analyses were used to obtain global expression profiles of mRNA abundance in the green alga Chlamydomonas reinhardtii at different time points before the onset and during the course of sulfur-depleted hydrogen production. These studies were followed by real-time quantitative reverse transcription-PCR and protein analyses. The present work provides new insights into photosynthesis, sulfur acquisition strategies, and carbon metabolism-related gene expression during sulfur-induced hydrogen production. A general trend toward repression of transcripts encoding photosynthetic genes was observed. In contrast to all other LHCBM genes, the abundance of the LHCBM9 transcript (encoding a major light-harvesting polypeptide) and its protein was strongly elevated throughout the experiment. This suggests a major remodeling of the photosystem II light-harvesting complex as well as an important function of LHCBM9 under sulfur starvation and photobiological hydrogen production. This paper presents the first global transcriptional analysis of C. reinhardtii before, during, and after photobiological hydrogen production under sulfur deprivation.

Nguyen, Anh Vu; Thomas-Hall, Skye R.; Malnoe, Alizee; Timmins, Matthew; Mussgnug, Jan H.; Rupprecht, Jens; Kruse, Olaf; Hankamer, Ben; Schenk, Peer M.

2008-01-01

322

Prospects in diatom research.  

PubMed

Diatoms are unicellular photosynthetic eukaryotes that play a major role in the global cycling of carbon and silicon. They are believed to have arisen from a secondary endosymbiotic event between two eukaryotes, a red alga and a flagellated heterotroph. Recent analysis of a diatom genome indeed reveals a 'mosaic' nature, with genes derived from plant, animal and bacterial lineages. Advances in molecular genomics are facilitating the use of diatom-specific genes or pathways for biotechnology. Another interest is in understanding the artistry of the amorphous silica shell and the underlying biomineralization process. Materials scientists and chemists are now exploiting diatoms to develop new biomimetic approaches and to create silicon-based microdevices with specific features. PMID:15831384

Lopez, Pascal J; Desclés, Julien; Allen, Andrew E; Bowler, Chris

2005-04-01

323

Acid water interferes with salamander-green algae symbiosis during early embryonic development.  

PubMed

The inner egg capsule of embryos of the yellow-spotted salamander (Ambystoma maculatum) are routinely colonized by green algae, such as Oophila amblystomatis, that supply O(2) in the presence of light and may consume nitrogenous wastes, forming what has been proposed to be a mutualistic relationship. Given that A. maculatum have been reported to breed in acidic (pH <5.0) and neutral lakes, we hypothesized that low water pH would negatively affect these symbiotic organisms and alter the gradients within the jelly mass. Oxygen gradients were detected within jelly masses measured directly in a natural breeding pond (pH 4.5-4.8) at midday in full sunlight. In the lab, embryo jelly masses reared continuously at pH 4.5 had lower P(O)?and higher ammonia levels relative to jelly masses held at pH 8.0 (control). Ammonia and lactate concentrations in embryonic tissues were approximately 37%-93% higher, respectively, in embryos reared at water pH 4.5 compared with pH 8.0. Mass was also reduced in embryos reared at pH 4.5 versus pH 8.0. In addition, light conditions (24 h light, 12L : 12D, or 24 h dark) and embryonic position (periphery vs. center) in the jelly mass affected P(O)?but not ammonia gradients, suggesting that algal symbionts generate O(2) but do not significantly impact local ammonia concentrations, regardless of the pH of the water. We conclude that chronic exposure to acidic breeding ponds had a profound effect on the microenvironment of developing A. maculatum embryos, which in turn resulted in an elevation of potentially harmful metabolic end products and inhibited growth. Under acidic conditions, the expected benefit provided by the algae to the salamander embryo (i.e., high O(2) and low ammonia microenvironment) is compromised, suggesting that the A. maculatum-algal mutualism is beneficial to salamanders only at higher water pH values. PMID:22902375

Bianchini, Kristin; Tattersall, Glenn J; Sashaw, Jessica; Porteus, Cosima S; Wright, Patricia A

2012-08-03

324

New Chemical Constituents from Oryza sativa Straw and Their Algicidal Activities against Blue-Green Algae.  

PubMed

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

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

2013-08-14

325

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

326

Inducing autoflocculation in the diatom Phaeodactylum tricornutum through CO 2 regulation  

Microsoft Academic Search

The effect of pH on flocculation was studied using the diatom Phaeodactylum tricornutum and the green algae Scenedesmus cf. obliquus as surrogate species. There was a distinct, species-specific threshold of pH where flocculation started. P. tricornutum started to flocculate at pH 10.5 and S. cf. obliquus at pH 11.3. Above this threshold, settling rates up to 360 cm h?1 were observed for P. tricornutum

Kristian Spilling; Jukka Seppälä; Timo Tamminen

327

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

PubMed

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

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

2011-12-05

328

Molecular phylogeny of conjugating green algae (Zygnemophyceae, Streptophyta) inferred from SSU rDNA sequence comparisons.  

PubMed

Nuclear-encoded SSU rDNA sequences have been obtained from 64 strains of conjugating green algae (Zygnemophyceae, Streptophyta, Viridiplantae). Molecular phylogenetic analyses of 90 SSU rDNA sequences of Viridiplantae (inciuding 78 from the Zygnemophyceae) were performed using complex evolutionary models and maximum likelihood, distance, and maximum parsimony methods. The significance of the results was tested by bootstrap analyses, deletion of long-branch taxa, relative rate tests, and Kishino-Hasegawa tests with user-defined trees. All results support the monophyly of the class Zygnemophyceae and of the order Desmidiales. The second order, Zygnematales, forms a series of early-branching clades in paraphyletic succession, with the two traditional families Mesotaeniaceae and Zygnemataceae not recovered as lineages. Instead, a long-branch Spirogyra/Sirogonium clade and the later-diverging Netrium and Roya clades represent independent clades. Within the order Desmidiales, the families Gonatozygaceae and Closteriaceae are monophyletic, whereas the Peniaceae (represented only by Penium margaritaceum) and the Desmidiaceae represent a single weakly supported lineage. Within the Desmidiaceae short internal branches and varying rates of sequence evolution among taxa reduce the phylogenetic resolution significantly. The SSU rDNA-based phylogeny is largely congruent with a published analysis of the rbcL phylogeny of the Zygnemophyceae (McCourt et al. 2000) and is also in general agreement with classification schemes based on cell wall ultrastructure. The extended taxon sampling at the subgenus level provides solid evidence that many genera in the Zygnemophyceae are not monophyletic and that the genus concept in the group needs to be revised. PMID:12569426

Gontcharov, Andrey A; Marin, Birger A; Melkonian, Michael A

2003-01-01

329

Assessing potential health risks from microcystin toxins in blue-green algae dietary supplements.  

PubMed

The presence of blue-green algae (BGA) toxins in surface waters used for drinking water sources and recreation is receiving increasing attention around the world as a public health concern. However, potential risks from exposure to these toxins in contaminated health food products that contain BGA have been largely ignored. BGA products are commonly consumed in the United States, Canada, and Europe for their putative beneficial effects, including increased energy and elevated mood. Many of these products contain Aphanizomenon flos-aquae, a BGA that is harvested from Upper Klamath Lake (UKL) in southern Oregon, where the growth of a toxic BGA, Microcystis aeruginosa, is a regular occurrence. M. aeruginosa produces compounds called microcystins, which are potent hepatotoxins and probable tumor promoters. Because M. aeruginosa coexists with A. flos-aquae, it can be collected inadvertently during the harvesting process, resulting in microcystin contamination of BGA products. In fall 1996, the Oregon Health Division learned that UKL was experiencing an extensive M. aeruginosa bloom, and an advisory was issued recommending against water contact. The advisory prompted calls from consumers of BGA products, who expressed concern about possible contamination of these products with microcystins. In response, the Oregon Health Division and the Oregon Department of Agriculture established a regulatory limit of 1 microg/g for microcystins in BGA-containing products and tested BGA products for the presence of microcystins. Microcystins were detected in 85 of 87 samples tested, with 63 samples (72%) containing concentrations > 1 microg/g. HPLC and ELISA tentatively identified microcystin-LR, the most toxic microcystin variant, as the predominant congener. PMID:10811570

Gilroy, D J; Kauffman, K W; Hall, R A; Huang, X; Chu, F S

2000-05-01

330

Loliolide in marine algae.  

PubMed

Loliolide content was determined in 13 marine algae including red, brown and green algae collected from the Black Sea, the Dardanelles and the Aegean Sea. Identification and quantification were performed by gas chromatography-mass spectrometry. The loliolide content in green alga is 1.76 microg g(-1), ranges from 0.14 to 4.35 microg g(-1) in red and from 0.18 to 4.83 microg g(-1) in brown algae. The results obtained are in the same range as previously reported for algae, as well as terrestrial plants. This article represents the first report of loliolide occurrence in green algae. PMID:19296390

Percot, Aline; Yalcin, Ahmet; Aysel, Veysel; Erdu?an, Hüseyin; Dural, Berrin; Güven, Kasim Cemal

2009-01-01

331

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

PubMed

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. PMID:17806931

Oehler, J H; Schopf, J W

1971-12-17

332

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

Microsoft Academic Search

? 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

DONALD F. KAPRAUN

2005-01-01

333

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

PubMed Central

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

Kalanon, Ming; McFadden, Geoffrey I.

2008-01-01

334

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

2012-06-16

335

[Early toxic effect of zinc, cobalt, and cadmium on photosynthetic activity of green alga Chlorella pyrenoidosa Chick S-39].  

PubMed

Early toxic effects of heavy metals (HMs) Zn, Co, and Cd in concentration from 0.01 to 100 mM on photosynthetic activity of the green alga Chlorella pyrenoidosa Chick S-39 were studied. The early effect of HMs was manifested as a rapid (0.5-2 h) reduction of photoinduced oxygen release by the algal cells. The suppressed relative yield of variable chlorophyll fluorescence ratio (Fv/Fm) by the metals as well as its dynamics in C. pyrenoidosa demonstrated rapid inactivation of photosystem II (PS II). Analysis of the induction curve of delayed chlorophyll fluorescence in Chlorella cells suggested that the early toxic effects of the tested concentrations of Zn, Co, and Cd included both reduced electron transport in PS II and decreased photosynthetic membrane energization. Hence, the early toxic effect of Zn, Co, and Cd was primarily related to the decreased efficiency of the light reactions of photosynthesis which further reduced the alga productivity later. PMID:14735794

Plekhanov, S E; Chemeris, Iu K

336

Caulerprenylols A and B, two rare antifungal prenylated para-xylenes from the green alga Caulerpa racemosa.  

PubMed

Two new prenylated para-xylenes, named caulerprenylols A (1) and B (2), were isolated from the green alga Caulerpa racemosa, collected from the Zhanjiang coastline, China. The structures of the two metabolites were elucidated on the basis of detailed spectroscopic analysis. This is the first report of prenylated para-xylenes from marine algae and from marine organisms as well. Moreover, caulerprenylol B (2) is also characterized by an uncommon indane ring system. In in vitro bioassays, the new compounds exhibited a broad spectrum of antifungal activity against Candida glabrata (537), Trichophyton rubrum (Cmccftla), and Cryptococcus neoformans (32609) with MIC80 values between 4 and 64 ?g/mL when compared to amphotericin B (MIC80 values of 2.0, 1.0, and 4.0 ?g/mL, respectively) as a positive control and showed no growth inhibition activity against the tumor cells HL60 and A549. PMID:23548547

Liu, Ai-Hong; Liu, Ding-Quan; Liang, Tong-Jun; Yu, Xiao-Qing; Feng, Mei-Tang; Yao, Li-Gong; Fang, Yi; Wang, Bin; Feng, Li-Hua; Zhang, Min-Xian; Mao, Shui-Chun

2013-03-19

337

Kinetics and uptake mechanisms for monomethylmercury between freshwater algae and water.  

PubMed

Uptake kinetics of monomethylmercury chloride (MeHgCl) were measured for two species of green algae (Selenastrum capricomutum and Cosmarium botrytis), one blue-green algae (Schizothrix calcicola), and one diatom (Thalassiosira weissflogii), algal species that are commonly found in natural surface waters. Species differences were found with the two green algae giving the highest uptake rates, and one of them (Cosmarium) showing differences between cultures having widely different cell age (exponential versus stationary), where increases in uptake rate for cells 30 days old were about 25 times greater than cells only 3 days old when weights of cells were considered. Both Schizothrix and Thalassiosira exhibited nearly the same lower uptake rates, approximately 20 times lower than the two green algal species. Experiments with photosystem inhibitors, uncouplers, gamma-radiation, light deprivation, and extended range uptake all point to an active transport mechanism for MeHgCl. PMID:12214648

Moye, H Anson; Miles, Carl J; Phlips, Edward J; Sargent, Bethany; Merritt, Kristen K

2002-08-15

338

Diatom Plastids Possess a Phosphoribulokinase with an Altered Regulation and No Oxidative Pentose Phosphate Pathway1  

PubMed Central

The chloroplast enzyme phosphoribulokinase (PRK; EC 2.7.1.19) is part of the Calvin cycle (reductive pentose phosphate pathway) responsible for CO2 fixation in photosynthetic organisms. In green algae and vascular plants, this enzyme is light regulated via reversible reduction by reduced thioredoxin. We have sequenced and characterized the gene of the PRK from the marine diatom Odontella sinensis and found that the enzyme has the conserved cysteine residues necessary for thioredoxin-dependent regulation. Analysis of enzymatic activity of partially purified diatom enzyme and of purified protein obtained by native overexpression in Escherichia coli, however, revealed that under natural redox conditions the diatom enzyme is generally active. Treatment of the enzyme with strong oxidants results in inhibition of the enzyme, which is reversible by subsequent incubation with reducing agents. We determined the redox midpoint potentials of the regulatory cysteine in the PRK from O. sinensis in comparison to the respective spinach (Spinacia oleracea) enzyme and found a more positive redox potential for the diatom PRK, indicating that in vivo this enzyme might not be regulated by thioredoxin. We also demonstrate that in protease-treated diatom plastids, activities of enzymes of the oxidative pentose phosphate pathway are not detectable, thus reducing the need for a tight regulation of the Calvin cycle in diatoms. We discuss our results in the context of rearrangements of the subcellular compartmentation of metabolic pathways due to the peculiar evolution of diatoms by secondary endocytobiosis.

Michels, Andreas K.; Wedel, Norbert; Kroth, Peter G.

2005-01-01

339

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

PubMed

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

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

1996-10-17

340

Expression of ?-carotene hydroxylase gene ( crtR-B ) from the green alga Haematococcus pluvialis in chloroplasts of Chlamydomonas reinhardtii  

Microsoft Academic Search

A carotenoid gene (crtR-B) from the green alga Haematococcus pluvialis, encoding ?-carotene hydroxylase that was able to catalyze the conversion of ?-carotene to zeaxanthin and canthaxanthin to\\u000a astaxanthin, was cloned into Chlamydomonas reinhardtii chloroplast expression vector p64D to yield plasmid p64DcrtR-B. The vector p64DcrtR-B was transferred to the chloroplast\\u000a genome of C. reinhardtii using micro-particle bombardment. PCR and Southern blot

Cong-Ping Tan; Fang-Qing Zhao; Zhong-Liang Su; Cheng-Wei Liang; Song Qin

2007-01-01

341

The complete plastid genome sequence of the parasitic green alga Helicosporidium sp. is highly reduced and structured  

Microsoft Academic Search

Background  Loss of photosynthesis has occurred independently in several plant and algal lineages, and represents a major metabolic shift\\u000a with potential consequences for the content and structure of plastid genomes. To investigate such changes, we sequenced the\\u000a complete plastid genome of the parasitic, non-photosynthetic green alga, Helicosporidium.\\u000a \\u000a \\u000a \\u000a \\u000a Results  The Helicosporidium plastid genome is among the smallest known (37.5 kb), and like other

Audrey P de Koning; Patrick J Keeling

2006-01-01

342

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

Microsoft Academic Search

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

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

1968-01-01

343

Localization and evolution of septins in algae.  

PubMed

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

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

2013-03-07

344

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

National Technical Information Service (NTIS)

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

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

2012-01-01

345

The Ecological Role of Rhizophytic Green Algae in Soft-bottom Habitats  

Microsoft Academic Search

Rhizophytic algae are large, abundant primary producers throughout tropical and subtropical areas worldwide where they grow as an understory in seagrass beds, as well as form mixed or monospecific beds of exclusively rhizophytic algal species. In this dissertation, \\

Laura Bedinger

2012-01-01

346

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

347

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

Microsoft Academic Search

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

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

1995-01-01

348

A new polyacetylenic fatty acid and other secondary metabolites from the Chinese green alga Caulerpa racemosa (Caulerpaceae) and their chemotaxonomic significance  

Microsoft Academic Search

A new polyacetylenic fatty acid, (8E,12Z,15Z)-10-hydroxy-8,12,15-octadecatrien-4,6-diynoic acid (1), together with five known metabolites, including two linear diterpenes (3 and 4) and three sterols (5–7), has been isolated from the Chinese green alga Caulerpa racemosa. Its structure was determined on the basis of extensive spectroscopic analysis. Compound 1 represents the first example of polyacetylenic lipids from marine algae up to now,

Shui-Chun Mao; Ding-Quan Liu; Xiao-Qing Yu; Xiao-Ping Lai

2011-01-01

349

Inhibition of the growth of two blue-green algae species ( Microsystis aruginosa and Anabaena spiroides) by acidification treatments using carbon dioxide  

Microsoft Academic Search

The effect of pH adjusted by aeration with carbon dioxide (CO2) on the growth of two species of blue-green algae, Microcystis aeruginosa and Anabaena spiroides, was investigated. Three conditions (pH 5.5, 6.0 and 6.5) were found to have significant inhibitory effects on the growth of the two algae species when acidification treatment was conducted during the logarithmic phase. Differences in

Xin Wang; Chunbo Hao; Feng Zhang; Chuanping Feng; Yingnan Yang

2011-01-01

350

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

Microsoft Academic Search

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 ¹⁴COâ followed a similar pattern with pH. The algal cells were also sensitive to

M. D. Baker; C. I. Mayfield; W. E. Inniss; P. T. S. Wong

1983-01-01

351

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

PubMed

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

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

2011-08-26

352

Survival and reproduction of some blue-green and green algae as affected by sewage water, fertilizer factory effluent, brassica oil, phenol, toluene and benzene.  

PubMed

Fourteen blue-green and green algae survived for widely different time periods ranging between 22-102 d in control culture medium. Irrespective of their long or short survival period in control cultures, their pro- or eukaryotic nature, their different morphological types or natural habitats, they all survived for a short time period ranging between 3-8 d in sewage water, 5-10 d in fertilizer factory effluent, (1/4)-2 d in brassica oil, (1/2)-2 d in phenol, 1-3 d in toluene, and 1-4 d in benzene (showing the relative toxicity of different chemicals to different algae, and the antialgal nature of brassica oil). Dilution decreased the toxicity of these agents very little, indicating that they all were very toxic to algae. None of the agent induced the formation of any reproductive or dormant cells. Sewage water, fertilizer factory effluent, brassica oil and/or benzene favored the formation of necridia cells in Phormidium bohneri, P. foveolarum, Microcoleus chthonoplastes, Lyngbya birgei, and L. major filaments. Scenedesmus quadricauda shed off all spines earlier, Hormidium flaccidum fragmented less or not at all, Scytonema millei formed no false branch and heterocyst, Aphanothece pallida and Gloeocapsa atrata cells did not divide, Cosmarium granatum cells did not form any zygospore and Oedogonium sp. not any oogonia-like cells under all or most of treatments with 25-100 % sewage water, 1-100 % fertilizer factory effluent, 1-100 % brassica oil, 25-100 % phenol, toluene and benzene. PMID:19330547

Agrawal, S C; Gupta, S

2009-03-29

353

The mitochondrial genome of Chara vulgaris: insights into the mitochondrial DNA architecture of the last common ancestor of green algae and land plants.  

PubMed

Mitochondrial DNA (mtDNA) has undergone radical changes during the evolution of green plants, yet little is known about the dynamics of mtDNA evolution in this phylum. Land plant mtDNAs differ from the few green algal mtDNAs that have been analyzed to date by their expanded size, long spacers, and diversity of introns. We have determined the mtDNA sequence of Chara vulgaris (Charophyceae), a green alga belonging to the charophycean order (Charales) that is thought to be the most closely related alga to land plants. This 67,737-bp mtDNA sequence, displaying 68 conserved genes and 27 introns, was compared with those of three angiosperms, the bryophyte Marchantia polymorpha, the charophycean alga Chaetosphaeridium globosum (Coleochaetales), and the green alga Mesostigma viride. Despite important differences in size and intron composition, Chara mtDNA strikingly resembles Marchantia mtDNA; for instance, all except 9 of 68 conserved genes lie within blocks of colinear sequences. Overall, our genome comparisons and phylogenetic analyses provide unequivocal support for a sister-group relationship between the Charales and the land plants. Only four introns in land plant mtDNAs appear to have been inherited vertically from a charalean algar ancestor. We infer that the common ancestor of green algae and land plants harbored a tightly packed, gene-rich, and relatively intron-poor mitochondrial genome. The group II introns in this ancestral genome appear to have spread to new mtDNA sites during the evolution of bryophytes and charalean green algae, accounting for part of the intron diversity found in Chara and land plant mitochondria. PMID:12897260

Turmel, Monique; Otis, Christian; Lemieux, Claude

2003-08-01

354

The Mitochondrial Genome of Chara vulgaris: Insights into the Mitochondrial DNA Architecture of the Last Common Ancestor of Green Algae and Land PlantsW?  

PubMed Central

Mitochondrial DNA (mtDNA) has undergone radical changes during the evolution of green plants, yet little is known about the dynamics of mtDNA evolution in this phylum. Land plant mtDNAs differ from the few green algal mtDNAs that have been analyzed to date by their expanded size, long spacers, and diversity of introns. We have determined the mtDNA sequence of Chara vulgaris (Charophyceae), a green alga belonging to the charophycean order (Charales) that is thought to be the most closely related alga to land plants. This 67,737-bp mtDNA sequence, displaying 68 conserved genes and 27 introns, was compared with those of three angiosperms, the bryophyte Marchantia polymorpha, the charophycean alga Chaetosphaeridium globosum (Coleochaetales), and the green alga Mesostigma viride. Despite important differences in size and intron composition, Chara mtDNA strikingly resembles Marchantia mtDNA; for instance, all except 9 of 68 conserved genes lie within blocks of colinear sequences. Overall, our genome comparisons and phylogenetic analyses provide unequivocal support for a sister-group relationship between the Charales and the land plants. Only four introns in land plant mtDNAs appear to have been inherited vertically from a charalean algar ancestor. We infer that the common ancestor of green algae and land plants harbored a tightly packed, gene-rich, and relatively intron-poor mitochondrial genome. The group II introns in this ancestral genome appear to have spread to new mtDNA sites during the evolution of bryophytes and charalean green algae, accounting for part of the intron diversity found in Chara and land plant mitochondria.

Turmel, Monique; Otis, Christian; Lemieux, Claude

2003-01-01

355

The Ecology of Diatoms in Hardwater Habitats.  

National Technical Information Service (NTIS)

Diatoms comprise the major group of algae in Iowa waters. Their ecological significance, important in pollution evaluation studies, cannot be fully appreciated without a thorough knowledge of their taxonomy. A scale for abundance rating was used giving at...

J. D. Dodd

1971-01-01

356

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

PubMed

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

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

2012-08-03

357

The Exceptionally Large Chloroplast Genome of the Green Alga Floydiella terrestris Illuminates the Evolutionary History of the Chlorophyceae  

PubMed Central

The Chlorophyceae, an advanced class of chlorophyte green algae, comprises five lineages that form two major clades (Chlamydomonadales + Sphaeropleales and Oedogoniales + Chaetopeltidales + Chaetophorales). The four complete chloroplast DNA (cpDNA) sequences currently available for chlorophyceans uncovered an extraordinarily fluid genome architecture as well as many structural features distinguishing this group from other green algae. We report here the 521,168-bp cpDNA sequence from a member of the Chaetopeltidales (Floydiella terrestris), the sole chlorophycean lineage not previously sampled for chloroplast genome analysis. This genome, which contains 97 conserved genes and 26 introns (19 group I and 7 group II introns), is the largest chloroplast genome ever sequenced. Intergenic regions account for 77.8% of the genome size and are populated by short repeats. Numerous genomic features are shared with the cpDNA of the chaetophoralean Stigeoclonium helveticum, notably the absence of a large inverted repeat and the presence of unique gene clusters and trans-spliced group II introns. Although only one of the Floydiella group I introns encodes a homing endonuclease gene, our finding of five free-standing reading frames having similarity with such genes suggests that chloroplast group I introns endowed with mobility were once more abundant in the Floydiella lineage. Parsimony analysis of structural genomic features and phylogenetic analysis of chloroplast sequence data unambiguously resolved the Oedogoniales as sister to the Chaetopeltidales and Chaetophorales. An evolutionary scenario of the molecular events that shaped the chloroplast genome in the Chlorophyceae is presented.

Brouard, Jean-Simon; Otis, Christian; Lemieux, Claude; Turmel, Monique

2010-01-01

358

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

PubMed Central

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

2009-01-01

359

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

2013-07-02

360

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

2011-12-29

361

Structure and significance of cruciate flagellar root systems in green algae: Female gametes of Bryopsis lyngbyei (Bryopsidales)  

NASA Astrophysics Data System (ADS)

The ultrastructure of the flagellar apparatus in the biflagellate female gametes of the green alga Bryopsis lyngbyei has been studied in detail. In the flagellum and basal body, microtubule septations occur in some of the B-tubules. The transition region of the flagellum is extremely long (260 290 nm), exhibits a stellate pattern in cross section but lacks the transverse diaphragm. The two basal bodies form an angle of 180° and overlap at their proximal ends. They are connected by a compound non-striated capping plate. Terminal caps associated with the capping plate partially close the proximal end of each basal body. A cruciate flagellar root system with three different types of microtubular roots is present, i. e. the flagellar apparatus does not show 180° rotational symmetry. One root type contains 2 microtubules which are connected to an elaborate cylindrical structure, presumably a mating structure. The opposite root exhibits 3 microtubules over its entire length and is not associated with a cylindrical structure. In their proximal parts both roots are linked to an underlying crescent body. The other two microtubular roots are probably identical and consist of 4 (or 5) microtubules which show configurational changes. These two identical roots insert into the capping plate and link to the inner side (i. e. the side adjacent to the other basal body) of each basal body, whereas the other two roots attach to the outer sides of each basal body. System I striated fibres are probably associated with each of the four roots, while system II fibres have not been observed. The flagellar apparatus of female gametes of B. lyngbyei shows many unique features but in some aspects resembles that of ulvalean algae. Functional and phylogenetic aspects of cruciate flagellar root systems in green algae are discussed.

Melkonian, M.

1981-09-01

362

Beyond micromachining: the potential of diatoms.  

PubMed

Diatoms are microscopic, single-celled algae that possess rigid cell walls (frustules) composed of amorphous silica. Depending on the species of diatom and the growth conditions, these frustules can display a wide range of different morphologies. It is possible to design and produce specific frustule morphologies that have potential applications in nanotechnology. PMID:10322443

Parkinson, J; Gordon, R

1999-05-01

363

Blushing effect of some carbohydrates on the green alga Dictyococcus cinnabarinus  

Microsoft Academic Search

Riassunto È studiato l'effetto di arrossamento provocato dall'aggiunta di alcuni zuccheri a colture sommerse dell'alga cloroficeaD. cinnabarinus. Questo effetto è dovuto alla formazione di cheto-carotenoidi, alla diminuzione delle clorofille ed alla degradazione dei cloroplasti. Le osservazioni al microscopio elettronico mettono in evidenza le variazioni della struttura dei cloroplasti.

F. Dentice di Accadia; Olga Gribanovski-Sassu; Nancy Lozano Reyes

1968-01-01

364

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

Microsoft Academic Search

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

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

2009-01-01

365

Artificial Microfossils: Experimental Studies of Permineralization of Blue-Green Algae in Silica  

Microsoft Academic Search

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

John H. Oehler; J. William Schopf

1971-01-01

366

Blue and green-light signals for gamete release in the brown alga, Silvetia compressa  

Microsoft Academic Search

The intertidal brown alga Silvetia compressa releases gametes from receptacles (the reproductive tissue) rapidly upon a dark transfer (following a photosynthesis-dependent period in the light, termed potentiation). In this study, the wavelength-dependence of this process was investigated. During the potentiation period in white light (WL), gametes are not released. However, gametes were released during potentiation in blue light (BL), or

Gareth A. Pearson; Ester A. Serrão; Matthew Dring; Rainer Schmid

2004-01-01

367

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

368

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

369

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

370

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

Microsoft Academic Search

Production of biofuel from algae is dependent on the microalgal biomass production rate and lipid content. Both biomass production and lipid accumulation are limited by several factors, of which nutrients play a key role. In this research, the marine microalgae Dunaliella tertiolecta was used as a model organism and a profile of its nutritional requirements was determined. Inorganic phosphate PO43-

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

2011-01-01

371

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

Microsoft Academic Search

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

Mitsuo Oguchi; Koji Otsubo; Keiji Nitta; Shigeki Hatayama

1987-01-01

372

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 90 min at 4C resulted in excellent extraction of these compounds. This extraction method was compared with a

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

2000-01-01

373

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

374

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

PubMed

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

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

2013-01-18

375

Single cell green algae reference materials with managed levels of heavy metals  

Microsoft Academic Search

Three batches of single cell green algal biomass have been produced as model substances for green biomass reference materials\\u000a with the aim of arriving at three different concentration levels for selected heavy metals in the same matrix. The green algal\\u000a biomass is produced in a water based culture medium in open and closed bioreactors. An outdoor open bioreactor technology\\u000a was

R. Zeisler; R. Dekner; E. Zeiller; J. Doucha; P. Mader; J. Ku?era

1998-01-01

376

Method for the quantification of the blue-green pigment “marennine” synthesized by the marine diatom Haslea ostrearia (Gaillon\\/Bory) Simonsen using HPLC gel-filtration and photodiode-array detection  

Microsoft Academic Search

This paper describes a new approach for quantifying marennine, a blue-green pigment synthesized by the marine diatom Haslea ostrearia, which is known to be responsible for the greening of cultured oysters in French coastal areas. The method uses gel-filtration\\u000a HPLC interfaced with a photodiode-array detector (PDA). Under the chromatographic conditions applied, the peak of marennine\\u000a is identified on the dextran

Jean-Bernard Pouvreau; Michèle Morançais; Joël Fleurence; Pierre Pondaven

2007-01-01

377

Importance of Nutrient Competition and Allelopathic Effects in Suppression of the Green Alga Scenedesmus obliquus by the Macrophytes Chara, Elodea and Myriophyllum  

Microsoft Academic Search

Possible allelopathic effects of substances released from the macrophytes Chara globularis, Elodea canadensis, Myriophyllum spicatum on the common green alga Scenedesmusobliquus were tested in the laboratory with plastic plants and untreated medium as controls. A two-phase approach was used in which first the effects of physical presence of plants was studied (phase I) followed by the effects of plant culture

M. F. L. L. W. Lürling; Gerben van Geest; Marten Scheffer

2006-01-01

378

Short-term effects of nutrient enrichment of the sediment and interactions between the seagrass Cymodocea nodosa and the introduced green alga Caulerpa taxifolia in a Mediterranean bay  

Microsoft Academic Search

Nutrient addition experiments provide a means for testing ecological theories concerning the effects of nutrient availability on community composition and development. Here we present the results of two reciprocal short-term (4 months) experiments testing for the effects of nutrient addition in the sediment and competitive interactions between the seagrass Cymodocea nodosa and the tropical green alga Caulerpa taxifolia. This study

Giulia Ceccherelli; Francesco Cinelli

1997-01-01

379

Growth of Daphnia magna males and females fed with the cyanobacterium Microcystis aeruginosa and the green alga Scenedesmus obliquus in different proportions  

Microsoft Academic Search

Laboratory experiments were used to study the sensitivity of both male and female Daphnia magna to a toxic cyanobacterium, Microcystis aeruginosa. Male and female D. magna were fed with M. aeruginosa and a green alga (Scenedesmus obliquus) in different mixtures that included 0%, 25%, 50%, 75% and 100% Microcystis. Growth of both males and females declined with increasing proportion of

M. F. L. L. W. Lürling; Wendy Beekman

2006-01-01

380

Functional response of Anodonta anatina feeding on a green alga and four strains of cyanobacteria, differing in shape, size and toxicity  

Microsoft Academic Search

We studied the functional response of the freshwater unionid bivalve Anodonta anatina, feeding on five phytoplankton strains differing in food quality: the small green alga Scenedesmus obliquus, a toxic and a non-toxic strain of the filamentous cyanobacterium Planktothrix agardhii and a toxic and a non-toxic strain of the coccoid cyanobacterium Microcystis aeruginosa. On S. obliquus, A. anatina had a type

Babette M. Bontés; Antonie M. Verschoor; L. Miguel Dionisio Pires; Ellen Donk; Bas W. Ibelings

381

Functional response of Anodonta anatina feeding on a green alga and four strains of cyanobacteria, differing in shape, size and toxicity  

Microsoft Academic Search

We studied the functional response of the freshwater unionid bivalve Anodonta anatina, feeding on five phytoplankton strains differing in food quality: the small green alga Scenedesmus obliquus, a toxic and a non-toxic strain of the filamentous cyanobacterium Planktothrix agardhii and a toxic and a non-toxic strain of the coccoid cyanobacterium Microcystis aeruginosa. On S. obliquus, A. anatina had a type

Babette M. Bontes; Antonie M. Verschoor; L. Miguel Dionisio Pires; Ellen van Donk; Bas W. Ibelings

2007-01-01

382

In vitro Vascular Effects Produced by Crude Aqueous Extract of Green Marine Algae, Cladophora patentiramea (Mont.) Kützing, in Aorta from Normotensive Rats  

Microsoft Academic Search

Objectives: To investigate the antihypertensive activity of aqueous extracts obtained from Malaysian coastal seaweeds and to determine the pharmacological mechanisms of the extracts on rat aorta in vitro. Materials and Methods: The antihypertensive activity of 11 species of seaweeds (5 brown, 1 red and 5 green algae) were tested by cumulative addition of the extracts to phenylephrine (PE)-precontracted Wistar-Kyoto (WKY)

Yee-Ling Lim; Shiueh-Lian Mok

2010-01-01

383

Effect of green manure and floodwater algae on diurnal fluctuations of floodwater pH and depth of aerobic soil layer under lowland rice conditions  

Microsoft Academic Search

The present investigation was undertaken to elucidate the effect of floodwater algae and green manure on floodwater pH and depth of aerobic soil layer which are mainly responsible for the nitrogen losses in lowland rice production systems. The study was conducted in an environmental chamber using a sandy loam soil. Cylindrical plastic bottles 7 cm in diameter were used and

H. S. Thind; D. L. Rowell

1997-01-01

384

High Light-Induced Changes in the Activities of Antioxidant Enzymes and the Accumulation of Astaxanthin in the Green Alga Haematococcus pluvialis  

Microsoft Academic Search

We investigated high light-induced alterations in antioxidant enzymes by exposing green vegetative cells of the alga Haematococcus pluvialis to excess irradiance to induce the production of astaxanthin, a carotenoid pigment. Total activity of catalase decre- ased approximately 70% after high light exposure, whereas glutathione peroxidase (GPX) activity was slightly enhanced. Total activity of superoxide dis- mutase and ascorbate peroxidase (APX)

Seul-Ki Park; EonSeon Jin; Choul-Gyun Lee; Mi-Young Lee

385

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

2013-09-05

386

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

387

How 5000 independent rowers coordinate their strokes in order to row into the sunlight: Phototaxis in the multicellular green alga Volvox  

Microsoft Academic Search

BACKGROUND: The evolution of multicellular motile organisms from unicellular ancestors required the utilization of previously evolved tactic behavior in a multicellular context. Volvocine green algae are uniquely suited for studying tactic responses during the transition to multicellularity because they range in complexity from unicellular to multicellular genera. Phototactic responses are essential for these flagellates because they need to orientate themselves

Noriko Ueki; Shigeru Matsunaga; Isao Inouye; Armin Hallmann

2010-01-01

388

Genome size differentiates co-occurring populations of the planktonic diatom Ditylum brightwellii (Bacillariophyta)  

Microsoft Academic Search

BACKGROUND: Diatoms are one of the most species-rich groups of eukaryotic microbes known. Diatoms are also the only group of eukaryotic micro-algae with a diplontic life history, suggesting that the ancestral diatom switched to a life history dominated by a duplicated genome. A key mechanism of speciation among diatoms could be a propensity for additional stable genome duplications. Across eukaryotic

Julie A Koester; Jarred E Swalwell; Peter von Dassow; E Virginia Armbrust

2010-01-01

389

Determination of growth rate depression of some green algae by atrazine  

SciTech Connect

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

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

1987-12-01

390

Raman spectroscopic insights into the chemical gradients within the wound plug of the green alga Caulerpa taxifolia.  

PubMed

The invasive unicellular green macroalga Caulerpa taxifolia has spread dramatically in the Mediterranean Sea over the last decades. Its success is based on rapid plug formation after wounding, to prevent the loss of cell content. This quick and efficient process involves the rapid transformation of the secondary metabolite caulerpenyne to the reactive 1,4-dialdehyde oxytoxin 2, which acts as a protein crosslinker. The main metabolites of the wound plug were identified as proteins, caulerpenyne derivatives, and sulfated polysaccharides. Because of a methodological deficit, however, the detailed distribution of the compounds within the wound plug of C. taxifolia was unknown. This study demonstrates the suitability of FT-Raman spectroscopy for the noninvasive in vivo determination of caulerpenyne and its derivatives, as well as ?-carotene, from signals with special spectral features within the wound plug and the adjacent intact alga tissue, with a resolution of 100 ?m. FT-Raman spectra allowed four different zones with distinct chemical compositions around the region of wounds to be characterized. Gradients of the investigated metabolites within the wound plug and the alga could be determined. Moreover, various caulerpenyne derivatives could be identified spectroscopically, and this has led to a mechanistic proposal for the internal and the external wound plug formation. PMID:23526760

Weissflog, Ina A; Grosser, Katharina; Bräutigam, Maximilian; Dietzek, Benjamin; Pohnert, Georg; Popp, Juergen

2013-03-25

391

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

392

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

PubMed Central

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

Sadka, Avi; Himmelhoch, Stanley; Zamir, Ada

1991-01-01

393

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

PubMed

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 16S rRNA genes and is about 4% shorter than that of the Escherichia coli gene. The 16S rRNA sequence of A. nidulans has 83% homology with that of tobacco chloroplast and 74% homology with that of E. coli. Possible stem and loop structures of A. nidulans 16S rRNA sequences resemble more closely those of chloroplast 16S rRNAs than those of E. coli 16S rRNA. These observations support the endosymbiotic theory of chloroplast origin. PMID:6412038

Tomioka, N; Sugiura, M

1983-01-01

394

Dark hexose metabolism by photoautotrophically and heterotrophically grown cells of the blue-green alga (Cyanobacterium) Nostoc sp. strain Mac.  

PubMed Central

Photoautotrophically grown cells of the blue-green alga (cyanobacterium) Nostoc sp. strain Mac assimilated and oxidized both glucose and fructose in the dark at different rates. The rate of fructose metabolism in these cells could be stimulated by casein hydrolysate, the effect being most pronounced at low sugar concentrations. This stimulation was not seen in cells grown heterotrophically in the dark, suggesting that it is a transitory phenomenon which disappears during the autotrophy-heterotrophy growth transition. The stimulation of fructose assimilation by casein hydrolysate was abolished by chloramphenicol or streptomycin, suggesting there are rate-limiting steps in protein biosynthesis in the dark that ultimately lead to inhibition of fructose uptake. Glucose metabolism did not show these phenomena, indicating there are differences in the metabolism of the two sugars.

Bottomley, P J; van Baalen, C

1978-01-01

395

Jasplakinolide, a novel actin targeting peptide, inhibits cell growth and induces actin filament polymerization in the green alga Micrasterias.  

PubMed

Jasplakinolide, a naturally occurring cyclodepsipeptide from the marine sponge Jaspis sp., known to induce actin polymerization and stabilization in vitro, markedly influences the morphogenetic process in the green alga Micrasterias when used in concentrations higher than 3 microM. Development of Micrasterias is inhibited or strongly retarded, malformations occur, and large vacuoles are formed. At the ultrastructural level, dense abnormal accumulations of filamentous structures have been found indicating actin filament polymerizing activities of the drug in situ. Moreover, displacement of organelles and aggregations of endoplasmic reticulum (ER) cisternae have been observed. Microtubule (MT) arrangement and MT-dependent processes remain undisturbed. Cells allowed to recover from jasplakinolide treatment continue their growth but show severe changes in the cell pattern and displacement of organelles, suggesting that even after removal of the drug, some basic features for the morphogenetic process remain altered. Jasplakinolide might be a useful tool for investigations on actin-dependent processes in the future. PMID:9415378

Holzinger, A; Meindl, U

1997-01-01

396

Kinesin-like proteins are involved in postmitotic nuclear migration of the unicellular green alga Micrasterias denticulata.  

PubMed

The unicellular green alga Micrasterias denticulata performs a two-directional postmitotic nuclear migration during development, a passive migration into the growing semicell, and a microtubule mediated backward migration towards the cell centre. The present study provides first evidence for force generation by motor proteins of the kinesin family in this process. The new kinesin specific inhibitor adociasulfate-2 causes abnormal nuclear displacement at 18 microM. AMP-PNP, a non hydrolyseable ATP analogue or the general ATPase inhibitors calyculin A and sodium orthovanadate also disturb nuclear migration. In addition kinesin-like proteins are detected by means of immunoblotting using antibodies against brain kinesin, plant derived antibodies to kinesin-like proteins and a calmodulin binding kinesin-like protein. Immunoelectron microscopy suggests a correlation of conventional kinesin-like proteins, but not of the calmodulin binding kinesin-like protein to the microtubule apparatus associated with the migrating nucleus. PMID:12175672

Holzinger, Andreas; Lütz-Meindl, Ursula

2002-01-01

397

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

2012-10-27

398

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

PubMed Central

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. Images

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

1991-01-01

399

Mitosis in the coenocytic green alga Boergesenia forbesii (Harvey) Feldmann (Siphonocladales, Ulvophyceae)  

Microsoft Academic Search

Mitosis in vegetative cells of the siphonocladalean algaBoergesenia forbesii (Harvey) Feldmann was investigated mainly by electron microscopy. The mitotic spindle was centric and closed. The interphase\\u000a nucleus contained a spherical nucleolus. The nucleolus was slightly dispersed at prophase, but nucleolar materials remained\\u000a during nearly all stages of mitosis. Kinetochores were evident on chromosomes. The polar regions of nuclear envelope had

Tomoko Itagaki; Shigeru Ogawa

1994-01-01

400

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

Microsoft Academic Search

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

Marek Eliáš; Ji?í Neustupa; Pavel Škaloud

2008-01-01

401

The Unicellular Green Alga Chlamydomonas reinhardtii as an Experimental System to Study Chloroplast RNA Metabolism  

Microsoft Academic Search

Chlamydomonas reinhardtii   has served as an experimental organism for studying photosynthetic processes. The recent development of molecular tools for\\u000a this organism together with efficient methods of genetic analysis and the availability of many photosynthesis mutants has\\u000a now made this alga a powerful model system for the analysis of chloroplast biogenesis. For example, techniques have been developed\\u000a to transfer recombinant DNA

J. Nickelsen; U. Kück

2000-01-01

402

Diversity, Distribution and Ecology of Green Algae and Cyanobacteria in Urban Habitats  

Microsoft Academic Search

\\u000a Eukaryotic algae and cyanobacteria occur virtually in every terrestrial habitat on our planet. Organisms belonging to these\\u000a groups are present even in some of the most extreme terrestrial environments, such as rocks in hot and cold deserts (Friedmann\\u000a and Ocampo-Friedmann, 1984), Antarctic soils (Broady, 1996) and highly acidic post-mining sites (Lukešová, 2001). As early\\u000a as the beginning of the nineteenth

Fabio Rindi

403

Persicivirga ulvanivorans sp. nov., a marine member of the family Flavobacteriaceae that degrades ulvan from green algae.  

PubMed

A rod shaped, Gram-stain-negative, chemo-organotrophic, heterotrophic, strictly aerobic, non-gliding bacterium, designated strain PLR(T), was isolated from faeces of the mollusc Aplysia punctata (Mollusca, Gastropoda) that had been fed with green algae belonging to the genus Ulva. The novel strain was able to degrade ulvan, a polysaccharide extracted from green algae (Chlorophyta, Ulvophyceae). The taxonomic position of strain PLR(T) was investigated by using a polyphasic approach. Strain PLR(T) was dark orange, oxidase-positive, catalase-positive and grew optimally at 25 °C, at pH 7.5 and in the presence of 2.5 % (w/v) NaCl with an oxidative metabolism using oxygen as the electron acceptor. Nitrate could not be used as the electron acceptor. Strain PLR(T) had a Chargaff's coefficient (DNA G+C content) of 35.3 mol%. Phylogenetic analysis based on the sequence of the 16S rRNA gene placed the novel strain in the family Flavobacteriaceae (phylum 'Bacteroidetes'), within a clade comprising Stenothermobacter spongiae, Nonlabens tegetincola, Sandarakinotalea sediminis, Persicivirga xylanidelens and Persicivirga dokdonensis. The closest neighbours of strain PLR(T) were P. xylanidelens and P. dokdonensis, sharing 95.2 and 95.5 % 16S rRNA gene sequence similarity, respectively. Phylogenetic inference and differential phenotypic characteristics demonstrated that strain PLR(T) represents a novel species of the genus Persicivirga, for which the name Persicivirga ulvanivorans sp. nov. is proposed. The type strain is PLR(T) (?= CIP 110082(T)?= DSM 22727(T)). PMID:20833882

Barbeyron, Tristan; Lerat, Yannick; Sassi, Jean-François; Le Panse, Sophie; Helbert, William; Collén, Pi Nyvall

2010-09-10

404

The Effect of Toxic Cyanobacteria (Blue-Green Algae) on Water Plants and Animal Cells  

Microsoft Academic Search

The eutrophication of the Sulejow reservoir dam in Poland is connected with the problem of toxicity of cyanobacterial blooming (blue-green algal blooming). The main species responsible for hepatotoxic \\

Z. Romanowska-Duda; J. Mankiewicz; M. Tarczy?ska; Z. Walter; M. Zalewski

2002-01-01

405

Diatoms in space: testing prospects for reliable diatom nanotechnology in microgravity  

Microsoft Academic Search

The worldwide effort to grow nanotechnology, rather than use lithography, focuses on diatoms, single cell eukaryotic algae with ornate silica shells, which can be replaced by oxides and ceramics, or reduced to elemental silicon, to create complex nanostructures with compositions of industrial and electronics importance. Diatoms produce an enormous variety of structures, some of which are microtubule dependent and perhaps

Richard Gordon; Richard B. Hoover; Jack A. Tuszynski; Javier de Luis; Philip J. Camp; Mary Ann Tiffany; Stephen S. Nagy; Mostafa Fayek; Pascal J. Lopez; Beatriz E. Lerner

2007-01-01

406

Diatom Paleolimnology Data Cooperative Home Page  

NSDL National Science Digital Library

The Phycology Section of the Patrick Center for Environmental Research, part of Philadelphia's Academy of Natural Science, presents the Diatom Paleolimnology Data Cooperative (DPDC). This database contains information on diatoms and related ecological and paleolimnological data applicable to the study of global climate change. Users have three search options: browse and download stratigraphic and calibration data sets; view individual diatom counts; or search for occurrences of specific taxa in all data sets. The site includes links to algae databases, also from the Academy of Natural Science. Researchers are encouraged to submit diatom core and surface sediment data to the DPDC.

1998-01-01

407

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.

Linka, Marc; Jamai, Aziz; Weber, Andreas P.M.

2008-01-01

408

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

409

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.

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

2008-01-01

410

Nitrogenase Activity in Cell-Free Extracts of the Blue-Green Alga, Anabaena cylindrica  

PubMed Central

Cell-free extracts with high nitrogenase activity were prepared by sonic oscillation and French press treatment from the blue-gree alga Anabaena cylindrica. Extracts were prepared from cells grown on a 95% N2–5% CO2 gas mixture followed by a period of nitrogen starvation under an atmosphere of 95% argon–5% CO2. No increase in the specific activity of extracts was achieved by breaking heterocysts. Activity (assayed by acetylene reduction) was found to be dependent on adenosine triphosphate (ATP), an ATP-generating system, and a low-potential reductant. Na2S2O2 employed as reductant supports higher rates of nitrogenase activity than reduced ferredoxin. The activity is associated with a small-particle fraction that can be sedimented by ultracentrifugation. In contrast to the particulate nitrogenase of Azotobacter, which is stable in air, the A. cylindrica nitrogenase is an oxygen sensitive as nitrogenase prepared from anaerobic bacteria.

Smith, R. V.; Evans, M. C. W.

1971-01-01

411

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

412

Salicylhydroxamic acid (SHAM) inhibition of the dissolved inorganic carbon concentrating process in unicellular green algae  

SciTech Connect

Rates of photosynthetic O{sub 2} evolution, for measuring K{sub 0.5}(CO{sub 2} + HCO{sub 3}{sup {minus}}) at pH 7, upon addition of 50 micromolar HCO{sub 3}{sup {minus}} to air-adapted Chlamydomonas, Dunaliella, or Scenedesmus cells, were inhibited up to 90% by the addition of 1.5 to 4.0 millimolar salicylhydroxamic acid (SHAM) to the aqueous medium. The apparent K{sub i}(SHAM) for Chlamydomonas cells was about 2.5 millimolar, but due to low solubility in water effective concentrations would be lower. Salicylhydroxamic acid did not inhibit oxygen evolution or accumulation of bicarbonate by Scenedesmus cells between pH 8 to 11 or by isolated intact chloroplasts from Dunaliella. Thus, salicylhydroxamic acid appears to inhibit CO{sub 2} uptake, whereas previous results indicate that vanadate inhibits bicarbonate uptake. These conclusions were confirmed by three test procedures with three air-adapted algae at pH 7. Salicylhydroxamic acid inhibited the cellular accumulation of dissolved inorganic carbon, the rate of photosynthetic O{sub 2} evolution dependent on low levels of dissolved inorganic carbon (50 micromolar NaHCO{sub 3}), and the rate of {sup 14}CO{sub 2} fixation with 100 micromolar ({sup 14}C)HCO{sub 3}{sup {minus}}. Salicylhydroxamic acid inhibition of O{sub 2} evolution and {sup 14}CO{sub 2}-fixation was reversed by higher levels of NaHCO{sub 3}. Thus, salicylhydroxamic acid inhibition was apparently not affecting steps of photosynthesis other than CO{sub 2} accumulation. Although salicylhydroxamic acid is an inhibitor of alternative respiration in algae, it is not known whether the two processes are related.

Goyal, A.; Tolbert, N.E. (Michigan State Univ., East Lansing (USA))

1990-03-01

413

An original adaptation of photosynthesis in the marine green alga Ostreococcus  

Microsoft Academic Search

Adaptation of photosynthesis in marine environment has been examined in two strains of the green, picoeukaryote Ostreococcus: OTH95, a surface\\/high-light strain, and RCC809, a deep-sea\\/low-light strain. Differences between the two strains include changes in the light-harvesting capacity, which is lower in OTH95, and in the photoprotection capacity, which is enhanced in OTH95. Furthermore, RCC809 has a reduced maximum rate of

Pierre Cardol; Benjamin Bailleul; Fabrice Rappaport; Evelyne Derelle; Daniel Béal; Cécile Breyton; Shaun Bailey; Francis André Wollman; Arthur Grossman; Hervé Moreau; Giovanni Finazzi

2008-01-01

414

Structure and biosynthesis of novel conjugated polyene fatty acids from the marine green alga Anadyomene stellata  

Microsoft Academic Search

Novel polyunsaturated fatty acids with four conjugated double bonds were found in extracts of the green macroalga,Anadyomene stellata. The isolation of five of these with different chain lengths and varying degrees of unsaturation ?16?5, 18?4, 20?5, 20?6,\\u000a and 22?7—was accomplished by organic extraction followed by a combination of vaccum and high-performarce liquid chromatography.\\u000a One of these that was a novel

Marina V. Mikhailova; Debra L. Bemis; Mitchell L. Wise; William H. Gerwick; James N. Norris; Robert S. Jacobs

1995-01-01

415

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

Microsoft Academic Search

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

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

2011-01-01

416

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

417

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

418

Short and long-term redox regulation of photosynthetic light energy distribution and photosystem stoichiometry by acetate metabolism in the green alga, Chlamydobotrys stellata  

Microsoft Academic Search

The effect of acetate metabolism on the light energy distribution between the two photosystems, on the PS II\\/PS I stoichiometry\\u000a and on the expression of psbA and psbB and psaA genes was investigated in the green alga, Chlamydobotrys stellata during autotrophic (CO2), mixotrophic (CO2 plus acetate) and photoheterotrophic (only acetate) cultivation. It was observed that acetate assimilation in the glyoxylate

László Kovács; Wolfgang Wiessner; Mihály Kis; Ferenc Nagy; Dierk Mende; Sándor Demeter

2000-01-01

419

ADP-ribosylation of actin from the green alga Chara corallina by Clostridium botulinum C2 toxin and Clostridium perfringens iota toxin  

Microsoft Academic Search

Summary The ability of two bacterial toxins to modify a plant actin by covalent ADP-ribosylation was tested in the green algaChara corallina. Using [32P]NAD, bothClostridium botulinum C2 toxin andClostridium perfringens iota toxin labelled a protein of Mr 42 kDa which comigrated with actin and was immunoprecipitated by a monoclonal anti-actin antibody. ADP-ribosylation ofChara actin was more efficient with iota toxin

F. Grolig; I. Just; K. Aktories

1996-01-01

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

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

422

Rubisco activase transcript (rca) abundance increases when the marine unicellular green alga Chlorococcum littorale is grown under high-CO2 stress  

Microsoft Academic Search

cDNA and the corresponding genomic DNA region encoding Rubisco activase were isolated from the unicellular green alga Chlorococcum littorale. The deduced amino acid sequence encoded by the cDNA was 403 amino acids long and exhibited important homology with those of other known Rubisco activases. Its N-terminal sequence was similar to the chloroplastic transit peptides in Chlamydomonas reinhardtii. The mature protein

Laurent Beuf; Norihide Kurano; Shigetoh Miyachi

1999-01-01

423

Cloning and expression of a gene coding for the major light-harvesting chlorophyll a\\/b protein of photosystem II in the green alga Dunaliella salina  

Microsoft Academic Search

Genes encoding proteins of the major light-harvesting complex of photosystem II (LHCII) in higher plants are well studied.\\u000a However, little is known about the corresponding genes in the green alga Dunaliella salina, although this knowledge might provide valuable information about the respective roles of each LHCII protein at the molecular\\u000a level under extreme environmental conditions. Here, we describe an additional

Liang Wei; Yi Cao; Linhan Bai; Xue Liang; Tingting Deng; Jing Li; Dairong Qiao

2007-01-01

424

The chloroplast chIL gene of the green alga Chlorella vulgaris C-27 contains a self-splicing group I intron  

Microsoft Academic Search

ThechiL gene product is involved in the light-independent synthesis of chlorophyll in photosynthetic bacteria, green algae and non-flowering plants. The chloroplast genome ofChlorella vulgaris strain C-27 contains the first example of a splitchiL gene, which is interrupted by a 951 bp group I intron in the coding region. In vitro synthesized pre-mRNA containing the entire intron and parts of the

Meenu Kapoor; Tatsuya Wakasugi; Koichi Yoshinaga; Masahiro Sugiura

1996-01-01

425

Phylogenetic position of the Oedogoniales within the green algae (Chlorophyta) and the evolution of the absolute orientation of the flagellar apparatus  

Microsoft Academic Search

The order Oedogoniales is made up of green algae with an unusual form of cytokinesis, a ring of flagella on the zoids, and\\u000a a complex sexual reproduction. The genera included in this order, Oedogonium, Oedocladium and Bulbochaete, differ in their type of habit. In this contribution we report a phylogenetic analysis using 18S ribosomal DNA sequences\\u000a from 66 species of

J. S. Alberghina; M. S. Vigna; V. A. Confalonieri

2006-01-01

426

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

427

The stoichiometry and antenna size of the two photosystems in marine green algae, Bryopsis maxima and Ulva pertusa, in relation to the light environment of their natural habitat.  

PubMed

The stoichiometry and antenna sizes of the two photosystems in two marine green algae, Bryopsis maxima and Ulva pertusa, were investigated to examine whether the photosynthetic apparatus of the algae can be related to the light environment of their natural habitat. Bryopsis maxima and Ulva pertusa had chlorophyll (Chl) a/b ratios of 1.5 and 1.8, respectively, indicating large levels of Chl b, which absorbs blue-green light, relative to Chl a. The level of photosystem (PS) II was equivalent to that of PS I in Bryopsis maxima but lower than that of PS I in Ulva pertusa. Analysis of Q(A) photoreduction and P-700 photo-oxidation with green light revealed that >50% of PS II centres are non-functional in electron transport. Thus, the ratio of the functional PS II to PS I is only 0.46 in Bryopsis maxima and 0.35 in Ulva pertusa. Light-response curves of electron transport also provided evidence that PS I had a larger light-harvesting capacity than did the functional PS II. Thus, there was a large imbalance in the light absorption between the two photosystems, with PS I showing a larger total light-harvesting capacity than PS II. Furthermore, as judged from the measurements of low temperature fluorescence spectra, the light energy absorbed by Chl b was efficiently transferred to PS I in both algae. Based on the above results, it is hypothesized that marine green algae require a higher ATP:NADPH ratio than do terrestrial plants to grow and survive under a coastal environment. PMID:15797939

Yamazaki, Jun-Ya; Suzuki, Takahisa; Maruta, Emiko; Kamimura, Yasumaro

2005-03-29

428

Spectral and Kinetic Analysis of the Energy Coupling in the PS I–LHC I Supercomplex from the Green Alga Chlamydomonas reinhardtii at 77 K  

Microsoft Academic Search

Energy transfer processes in the chlorophyll antenna of the PS I–LHCI supercomplexes from the green alga Chlamydomonas reinhardtii have been studied at 77 K using transient absorption spectroscopy with multicolor excitation in the 640–670 nm region. Comparison of the kinetic data obtained at low and room temperatures indicates that the slow ?\\u000a?100 ps excitation equilibration phase that is characteristic of energy coupling

Alexander N. Melkozernov; Joanna Kargul; Su Lin; James Barber; Robert E. Blankenship

2005-01-01

429

Characterization of Chlorophyll–protein Complexes Isolated from Two Marine Green Algae, Bryopsis maxima and Ulva pertusa , Growing in the Intertidal Zone  

Microsoft Academic Search

Three Chl–protein complexes were isolated from thylakoid membranes of Bryopsis maxima and Ulva pertusa, marine green algae that inhabit the intertidal zone of the Pacific Ocean off the eastern coast of Japan by dodecyl-?-d-maltoside polyacrylamide gel electrophoresis. The slowest-moving fractions showed low Chl a\\/b and Chl\\/P-700 ratios, indicating that this fraction corresponds to complexes in PS I, which is large

Jun-ya Yamazaki; Arisu Kozu; Yuko Fukunaga

2006-01-01

430

Biosorption of Cr 3+, Cd 2+ and Cu 2+ ions by blue–green algae Spirulina sp.: kinetics, equilibrium and the mechanism of the process  

Microsoft Academic Search

The process of biosorption of heavy metal ions (Cr3+, Cd2+, Cu2+) by blue–green algae Spirulina sp. is discussed in this paper. Spirulina sp. was found to be a very efficient biosorbent. The aim of the present study was to investigate quantitatively the potential binding sites present at the surface of Spirulina sp., using both potentiometric titrations and adsorption isotherms. The

Katarzyna Chojnacka; Andrzej Chojnacki; Helena Górecka

2005-01-01

431

In vitro and in vivo safety assessment of edible blue-green algae, Nostoc commune var. sphaeroides Kützing and Spirulina plantensis  

Microsoft Academic Search

Blue-green algae (BGA) have been consumed as food and herbal medicine for centuries. However, safety for their consumption has not been well investigated. This study was undertaken to evaluate in vitro and in vivo toxicity of cultivated Nostoc commune var. sphaeroides Kützing (NO) and Spirulina platensis (SP). Neither NO nor SP contained detectable levels of microcystin (MC)-LA, MC-RR, MC-LW and

Yue Yang; Youngki Park; David A. Cassada; Daniel D. Snow; Douglas G. Rogers; Jiyoung Lee

2011-01-01

432

Flow shear induced cross-stream migration by a green alga  

NASA Astrophysics Data System (ADS)

Swimming and migration characteristics of micro-organisms in shear flows has overarching implications in formation of biological thin layers in aquatic ecosystems, design of bioreactors, and cell separations. Experiments are conducted in a microfluidic channel using digital holographic microscopy. A motile micro-alga, Dunaliella primolecta, is studied in a laminar shear flow at maximum shear rates ranging from 0.1 to 25 s-1. It is found that D. primolecta cells aggregate in the direction of positive vorticity when a critical local shear rate of 5 s-1 is reached. Unlike nonmotile cells, D. primolecta in high shear flow do not rotate along the Jeffrey orbits, neither resumes the local vorticity of flow. The torque on cell body is counter-acted by the spatial alignment of beating flagella. It is speculated that under severe viscous stresses, motile cells "opt" to align themselves in the direction where the least stresses are experienced on cell wall. Beating of flagella, which prevents cells from assuming local flow vorticity, consequently propel them in the span wise direction and allow them to disperse only in a thin two-dimensional layer.

Chengala, Anwar; Hondzo, Miki; Sheng, Jian

2010-11-01

433

Transcriptional analysis of cell growth and morphogenesis in the unicellular green alga Micrasterias (Streptophyta), with emphasis on the role of expansin  

PubMed Central

Background Streptophyte green algae share several characteristics of cell growth and cell wall formation with their relatives, the embryophytic land plants. The multilobed cell wall of Micrasterias denticulata that rebuilds symmetrically after cell division and consists of pectin and cellulose, makes this unicellular streptophyte alga an interesting model system to study the molecular controls on cell shape and cell wall formation in green plants. Results Genome-wide transcript expression profiling of synchronously growing cells identified 107 genes of which the expression correlated with the growth phase. Four transcripts showed high similarity to expansins that had not been examined previously in green algae. Phylogenetic analysis suggests that these genes are most closely related to the plant EXPANSIN A family, although their domain organization is very divergent. A GFP-tagged version of the expansin-resembling protein MdEXP2 localized to the cell wall and in Golgi-derived vesicles. Overexpression phenotypes ranged from lobe elongation to loss of growth polarity and planarity. These results indicate that MdEXP2 can alter the cell wall structure and, thus, might have a function related to that of land plant expansins during cell morphogenesis. Conclusions Our study demonstrates the potential of M. denticulata as a unicellular model system, in which cell growth mechanisms have been discovered similar to those in land plants. Additionally, evidence is provided that the evolutionary origins of many cell wall components and regulatory genes in embryophytes precede the colonization of land.

2011-01-01

434

Purification and characterization of putative alkaline [Ni-Fe] hydrogenase from unicellular marine green alga, Tetraselmis kochinensis NCIM 1605.  

PubMed

Hydrogenase enzyme from the unicellular marine green alga Tetraselmis kochinensis NCIM 1605 was purified 467 fold to homogeneity. The molecular weight was estimated to be approximately 89kDa by SDS-PAGE. This enzyme consists of two subunits with molecular masses of approximately 70 and approximately 19kDa. The hydrogenase was found to contain 10g atoms of Fe and 1g of atom of Ni per mole of protein. The specific activity of hydrogen evolution was 50micromol H(2)/mg/h of enzyme using reduced methyl viologen as an electron donor. This hydrogenase enzyme has pI value approximately 9.6 representing its alkaline nature. The absorption spectrum of the hydrogenase enzyme showed an absorption peak at 425nm indicating that the enzyme had iron-sulfur clusters. The total of 16 cysteine residues were found per mole of enzyme under the denaturing condition and 20 cysteine residues in reduced denatured enzyme indicating that it has two disulfide bridges. PMID:17321121

Bhosale, S H; Pant, A; Khan, M I

2007-02-23

435

Co-Evolution of Mitochondrial tRNA Import and Codon Usage Determines Translational Efficiency in the Green Alga Chlamydomonas  

PubMed Central

Mitochondria from diverse phyla, including protozoa, fungi, higher plants, and humans, import tRNAs from the cytosol in order to ensure proper mitochondrial translation. Despite the broad occurrence of this process, our understanding of tRNA import mechanisms is fragmentary, and crucial questions about their regulation remain unanswered. In the unicellular green alga Chlamydomonas, a precise correlation was found between the mitochondrial codon usage and the nature and amount of imported tRNAs. This led to the hypothesis that tRNA import might be a dynamic process able to adapt to the mitochondrial genome content. By manipulating the Chlamydomonas mitochondrial genome, we introduced point mutations in order to modify its codon usage. We find that the codon usage modification results in reduced levels of mitochondrial translation as well as in subsequent decreased levels and activities of respiratory complexes. These effects are linked to the consequential limitations of the pool of tRNAs in mitochondria. This indicates that tRNA mitochondrial import cannot be rapidly regulated in response to a novel genetic context and thus does not appear to be a dynamic process. It rather suggests that the steady-state levels of imported tRNAs in mitochondria result from a co-evolutive adaptation between the tRNA import mechanism and the requirements of the mitochondrial translation machinery.

Salinas, Thalia; Duby, Franceline; Larosa, Veronique; Coosemans, Nadine; Bonnefoy, Nathalie; Motte, Patrick; Marechal-Drouard, Laurence; Remacle, Claire

2012-01-01

436

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

2012-07-02

437

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.

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

1995-01-01

438

The effects of isopropyl N-phenyl carbamate on the green alga Oedogonium cardiacum. I. Cell division.  

PubMed

Cell division in vegetative filaments of the green alga Oedogonium cardiacum is presented as an experimental system. We report on how we have used this system to study the effects of isopropyl N-phenylcarbamate (IPC) on the mitotic apparatus and on the phycoplast, a planar array of cytokinetic microtubules. Polymerization of microtubules was prevented when filaments, synchronized by a light/dark regime and chilled (2 degrees C) while in metaphase or just before phycoplast formation, were exposed to 5.5 x 10(-4) M IPC and then returned to room temperature. Spindles reformed or phycoplasts formed when these filaments were transferred to growth medium free of IPC. However, the orientation of both microtubular systems was disturbed: the mitotic apparatus often contained three poles, frequently forming three daughter nuclei upon karyokinesis; the phycoplast was often stellate rather than planar, and it sometimes was displaced to the side of both daughter nuclei, resulting in a binucleate and an anucleate cell upon cytokinesis. Our results suggest that IPC (a) prevents the assembly of microtubules, (b) increases the number of functional polar bodies, and (c) affects the orientation of microtubules in O. cardiacum. High voltage (1,000 kV) electron microscopy of 0.5-microm thick sections allowed us to visualize the polar structures, which were not discernible in thin sections. PMID:4419583

Coss, R A; Pickett-Heaps, J D

1974-10-01

439

An Enzymatic Conversion of Lipoxygenase Products by a Hydroperoxide Lyase in Blue-Green Algae (Oscillatoria sp.)  

PubMed Central

An enzyme has been isolated from blue-green algae Oscillatoria sp. which utilizes the product, 13-hydroperoxy-9, 11-octadecadienoic acid (13-HPOD), of lipoxygenase for its substrate. This enzyme, termed hydroperoxide lyase, converts the conjugated diene 13-hydroperoxide of linoleic acid to 13-oxotrideca-9, 11-dienoic acid. The structure of the latter has been determined by ultraviolet spectroscopy and mass spectrometry. 9-HPOD is not a substrate for this enzyme. The hydroperoxide lyase from Oscillatoria sp. has a maximum of activity at pH 6.4 and 30°C. The molecular weight of the enzyme was estimated at 56,000. The enzyme was not inhibited by BW 755C, but was inhibited by molecules containing more than one hydroxyl group. Quercetin was found to be the best inhibitor of the enzyme activity. The purified hydroperoxide lyase from Oscillatoria sp. showed an apparent Km of 7.4 micromolar and a Vmax of 35 nanomoles per minute per milligram of protein for 13-HPOD. An enzymatic pathway for the biogenesis of oxodienoic acid from linoleic acid is proposed. This involves the sequential activity of lipoxygenase and hydroperoxide lyase enzymes.

Andrianarison, Rivo-Hery; Beneytout, Jean-Louis; Tixier, Marie

1989-01-01

440

Purification and biochemical characterisation of a glucose-6-phosphate dehydrogenase from the psychrophilic green alga Koliella antarctica.  

PubMed

Psychrophilic organisms have evolved a number of modifications of cellular structures to survive in the cold environment; among them it is worth noting an increased efficiency of enzymes at lower temperatures. Glucose-6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) was purified and characterised from the psychrophilic green alga Koliella antarctica (Trebouxiophyceae, Chlorophyta) from the Ross Sea (Antarctica). It was possible to isolate a single G6PDH using biochemical strategies; its maximum activity was measured at 35 °C, and the enzyme showed an E (a) of 39.6 kJ mol(-1). This protein reacted with antibodies raised against higher plants plastidic isoforms. KaG6PDH showed peculiar kinetic properties, with a K (iNADPH) value lower than [Formula: see text]. Notably, catalytic activity was inactivated in vitro by DTT and chloroplastic thioredoxin f. These biochemical properties of G6PDH are discussed with respect to higher plant G6PDHs and the adaptation of K. antarctica to polar low-temperature environment. PMID:23117891

Ferrara, Myriam; Guerriero, Gea; Cardi, Manuela; Esposito, Sergio

2012-11-02

441

Toxicant Induced Changes on Delayed Fluorescence Decay Kinetics of Cyanobacteria and Green Algae: A Rapid and Sensitive Biotest  

PubMed Central

Algal tests have developed into routine tools for testing toxicity of pollutants in aquatic environments. Meanwhile, in addition to algal growth rates, an increasing number of fluorescence based methods are used for rapid and sensitive toxicity measures. The present study stresses the suitability of delayed fluorescence (DF) as a promising parameter for biotests. DF is based on the recombination fluorescence at the reaction centre of photosystem II, which is emitted only by photosynthetically active cells. We analyzed the effects of three chemicals (3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), 3,5 Dichlorophenol (3,5 DCP) and copper) on the shape of the DF decay kinetics for potential use in phytoplankton toxicity tests. The short incubation tests were done with four phytoplankton species, with special emphasis on the cyanobacterium Microcystis aeruginosa. All species exhibited a high sensitivity to DCMU, but cyanobacteria were more affected by copper and less by 3,5 DCP than the tested green algae. Analyses of changes in the DF decay curve in response to the added chemicals indicated the feasibility of the DF decay approach as a rapid and sensitive testing tool.

Leunert, Franziska; Grossart, Hans-Peter; Gerhardt, Volkmar; Eckert, Werner

2013-01-01

442

Influence of the CO2 absorbent monoethanolamine on growth and carbon fixation by the green alga Scenedesmus sp.  

PubMed

The influence of monoethanolamine (MEA) as a CO(2) absorbent on photoautotrophic culture of CO(2)-fixing microalgae was investigated. When 300 ppm MEA (4.92 mM) was added to blank culture medium, the dissolved inorganic carbon and the molar absorption ratio increased to 51.0mg/L and 0.34 mol CO2 = mol MEA, respectively, which was an almost 6-fold increase in CO(2) solubility. When free MEA up to 300 mg/L was added to a green alga Scenedesmus sp. culture that was supplied 5% (v/v) CO(2) at 0.1 vvm, both cell growth rate and final cell density were enhanced compared to when no MEA was added. The cell growth rate reached 288.6 mg/L/d, which was equivalent to 539.6 mg-CO(2)/L/d as a CO(2)-fixation rate and enhancement of about 63.0% compared to not adding MEA. Chlorophyll-a content and nitrate consumption rate increased correspondingly. MEA doses higher than 400mg/L inhibited cell growth, probably due to toxicity of the carbamate intermediate. PMID:22771020

Choi, Wookjin; Kim, Garam; Lee, Kisay

2012-06-16

443

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

PubMed

Aphanizomenon flos-aquae (AFA) is a fresh water unicellular blue-green alga (cyanophyta) rich in phycocyanin (PC), a photosynthetic pigment with antioxidant and anti-inflammatory properties. The purpose of this study was to evaluate the ability of a novel natural extract from AFA enriched with PC to protect normal human erythrocytes and plasma samples against oxidative damage in vitro. In red blood cells, oxidative hemolysis and lipid peroxidation induced by the aqueous peroxyl radical generator [2,2'-Azobis (2-amidinopropane) dihydrochloride, AAPH] were significantly lowered by the AFA extract in a time- and dose-dependent manner; at the same time, the depletion of cytosolic glutathione was delayed. In plasma samples, the natural extract inhibited the extent of lipid oxidation induced by the pro-oxidant agent cupric chloride (CuCl2); a concomitant increase of plasma resistance to oxidation was observed as evaluated by conjugated diene formation. The involvement of PC in the antioxidant protection of the AFA extract against the oxidative damage was demonstrated by investigating the spectral changes of PC induced by AAPH or CuCl2. The incubation of the extract with the oxidizing agents led to a significant decrease in the absorption of PC at 620 nm accompanied with disappearance of its blue color, thus indicating a rapid oxidation of the protein. In the light of these in vitro results, the potential clinical applications of this natural compound are under investigation. PMID:15350832

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

2004-09-24

444

Chondramides, novel cyclodepsipeptides from myxobacteria, influence cell development and induce actin filament polymerization in the green alga Micrasterias.  

PubMed

The effects of chondramides A-D, new actin targeting cyclodepsipeptides from the myxobacterium Chondromyces crocatus, are probed on the unicellular green alga Micrasterias denticulata, a model organism for studies on cytomorphogenesis. All four chondramides readily enter the cells and cause severe shape malformations when applied during growth. However, the four derivatives have different lowest effective concentrations. Chondramide A: 20 microM, chondramide B: 15 microM, chondramide C: 5 microM chondramide D: 10 microM. At the ultrastructural level, chondramide C, the most effective drug, causes the appearance of abnormal, dense F-actin bundles, and a substantial increase in ER, which covers large parts of the developing semicell. Also the secondary cell wall is malformed by the drug. When chondramide C effects are investigated by means of indirect immunofluorescence, alterations of the F-actin system are also visible. Instead of the cortical F-actin network of untreated controls, distinct parts of the cell are covered by abundant F-actin aggregations. Phalloidin staining of chondramide C treated cells results in a decreased fluorescence in a time-dependent manner due to binding competitions between these drugs. F-actin polymerizing and bundling capacities of chondramides A-D are presented in Micrasterias for the first time, and may in future make this substances a useful tool for cell biological research. PMID:11169761

Holzinger, A; Lütz-Meindl, U

2001-02-01

445

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

2013-08-01

446

Removal of basic yellow dye from aqueous solution by sorption on green alga Caulerpa scalpelliformis.  

PubMed

Dynamic batch experiments were carried out for the biosorption of basic yellow dye on to the green macroalgae Caulerpa scalpelliformis. The factors affecting the sorption process such as the initial concentration of the dye and pH of the solution, the adsorbent dosage and the time of contact were studied. The sorption kinetics followed pseudo-second order kinetic model. The Caulerpa species exhibited a maximum uptake of 27 mg of dye per gram of seaweed. The Boyd's plot confirmed the external mass transfer as the rate-limiting step. The average effective diffusion coefficient was found to be 2.47 x 10(-4)cm(2)/s. Sorption equilibrium studies demonstrated that the biosorption followed Freundlich isotherm model, which implies a heterogeneous sorption phenomenon. Various thermodynamic parameters such as enthalpy of sorption DeltaH degrees , free energy change DeltaG degrees and entropy DeltaS degrees were estimated. The negative value of DeltaH degrees and negative values of DeltaG degrees show the sorption process is exothermic and spontaneous. The negative value of entropy DeltaS degrees shows the decreased randomness at the solid-liquid interface during the sorption of dyes onto green seaweed. PMID:16938392

Aravindhan, Rathinam; Rao, Jonnalagadda Raghava; Nair, Balachandran Unni

2006-07-31

447

Isolation and characterization of a novel chytrid species (phylum Blastocladiomycota), parasitic on the green alga Haematococcus.  

PubMed

A parasite was found in cultures of the green microalga Haematococcus pluvialis that grew epibiotically on algal cells and caused epidemics resulting in damage to the host cultures. The parasite was isolated into axenic culture on solid and liquid media. It was demonstrated to be the sole causative agent of the epidemics. According to its life cycle and phylogenetic analysis based on 18S ribosomal DNA sequences, the pathogen appears to represent a novel chytrid fungus closely related to the vascular plant pathogen Physoderma (Blastocladiomycota), although it differs from all other known chytrids by its infective stage, a wall-less propagule endowed with amoeboid motion and lacking the group's typical flagellum. PMID:18222678

Hoffman, Yoram; Aflalo, Claude; Zarka, Aliza; Gutman, Jenia; James, Timothy Y; Boussiba, Sammy

2007-09-20

448

Alkaloids in Marine Algae  

PubMed Central

This paper presents the alkaloids found in green, brown and red marine algae. Algal chemistry has interested many researchers in order to develop new drugs, as algae include compounds with functional groups which are characteristic from this particular source. Among these compounds, alkaloids present special interest because of their pharmacological activities. Alkaloid chemistry has been widely studied in terrestrial plants, but the number of studies in algae is insignificant. In this review, a detailed account of macro algae alkaloids with their structure and pharmacological activities is presented. The alkaloids found in marine algae may be divided into three groups: 1. Phenylethylamine alkaloids, 2. Indole and halogenated indole alkaloids, 3. Other alkaloids.

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

2010-01-01

449

An original adaptation of photosynthesis in the marine green alga Ostreococcus.  

PubMed

Adaptation of photosynthesis in marine environment has been examined in two strains of the green, picoeukaryote Ostreococcus: OTH95, a surface/high-light strain, and RCC809, a deep-sea/low-light strain. Differences between the two strains include changes in the light-harvesting capacity, which is lower in OTH95, and in the photoprotection capacity, which is enhanced in OTH95. Furthermore, RCC809 has a reduced maximum rate of O(2) evolution, which is limited by its decreased photosystem I (PSI) level, a possible adaptation to Fe limitation in the open oceans. This decrease is, however, accompanied by a substantial rerouting of the electron flow to establish an H(2)O-to-H(2)O cycle, involving PSII and a potential plastid plastoquinol terminal oxidase. This pathway bypasses electron transfer through the cytochrome b(6)f complex and allows the pumping of "extra" protons into the thylakoid lumen. By promoting the generation of a large DeltapH, it facilitates ATP synthesis and nonphotochemical quenching when RCC809 cells are exposed to excess excitation energy. We propose that the diversion of electrons to oxygen downstream of PSII, but before PSI, reflects a common and compulsory strategy in marine phytoplankton to bypass the constraints imposed by light and/or nutrient limitation and allow successful colonization of the open-ocean marine environment. PMID:18511560

Cardol, Pierre; Bailleul, Benjamin; Rappaport, Fabrice; Derelle, Evelyne; Béal, Daniel; Breyton, Cécile; Bailey, Shaun; Wollman, Francis André; Grossman, Arthur; Moreau, Hervé; Finazzi, Giovanni

2008-05-29

450

An original adaptation of photosynthesis in the marine green alga Ostreococcus  

PubMed Central

Adaptation of photosynthesis in marine environment has been examined in two strains of the green, picoeukaryote Ostreococcus: OTH95, a surface/high-light strain, and RCC809, a deep-sea/low-light strain. Differences between the two strains include changes in the light-harvesting capacity, which is lower in OTH95, and in the photoprotection capacity, which is enhanced in OTH95. Furthermore, RCC809 has a reduced maximum rate of O2 evolution, which is limited by its decreased photosystem I (PSI) level, a possible adaptation to Fe limitation in the open oceans. This decrease is, however, accompanied by a substantial rerouting of the electron flow to establish an H2O-to-H2O cycle, involving PSII and a potential plastid plastoquinol terminal oxidase. This pathway bypasses electron transfer through the cytochrome b6f complex and allows the pumping of “extra” protons into the thylakoid lumen. By promoting the generation of a large ?pH, it facilitates ATP synthesis and nonphotochemical quenching when RCC809 cells are exposed to excess excitation energy. We propose that the diversion of electrons to oxygen downstream of PSII, but before PSI, reflects a common and compulsory strategy in marine phytoplankton to bypass the constraints imposed by light and/or nutrient limitation and allow successful colonization of the open-ocean marine environment.

Cardol, Pierre; Bailleul, Benjamin; Rappaport, Fabrice; Derelle, Evelyne; Beal, Daniel; Breyton, Cecile; Bailey, Shaun; Wollman, Francis Andre; Grossman, Arthur; Moreau, Herve; Finazzi, Giovanni

2008-01-01

451

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

452

Antioxidant and free radical scavenging properties of marennine, a blue-green polyphenolic pigment from the diatom Haslea ostrearia (Gaillon/Bory) Simonsen responsible for the natural greening of cultured oysters.  

PubMed

Among microalgae, the marine diatom Haslea ostrearia has the distinctive feature of synthesizing and releasing, into the surrounding environment, a blue-green polyphenolic pigment called marennine. The oyster-breeding industry commonly makes use of this natural phenomenon for the greening of oysters grown in the ponds of the French Atlantic coast. This article reports the in vitro antioxidant properties of pure marennine. Two kinds of evaluation systems were adopted to test the antioxidative activity of marennine: antioxidant capacity assays (beta-carotene and thymidine protection assays and iron reducing power assay) and free radical scavenging assays (DPPH*, O2*-, and HO*). In almost all cases, marennine exhibited significantly higher antioxidative and free radical scavenging activities than natural and synthetic antioxidants commonly used in food, as shown by comparing median effective concentration (EC 50) values, for each test independently. This medium mol