| biocalcification by the marine alga emiliania huxleyi (lohmann) kamptner. | | 1979 | 499216 |
| determination of the absolute configuration of mono-saccharides in complex carbohydrates by capillary g.l.c. | the absolute configuration of neutral monosaccharides, 2-acetamido-2-deoxy sugars, and uronic acids can be determined by capillary g.l.c. on se-30 after glycosidation with (-)-2-butanol and protection of the remaining polar groups. the method is illustrated by application to mixtures of the constituent sugars of the capsular polysaccharide from klebsiella type 57, alpha 1-acid glycoprotein, mucus glycoproteins, and the methylated, acidic polysaccharide from the coccoliths of emiliania huxleyi (l ... | 1979 | 519653 |
| isolation and characterization of a ca2+ -binding polysaccharide associated with coccoliths of emiliania huxleyi (lohmann) kamptner. | c-occolithophoridae, a group of mostly unicellular algae, possess a cell wall containing calcified plates, called coccoliths. the coccoliths from the species emilania huxleyi (lohmann) kamptner contain a water-soluble acid polysaccharide. in this paper we describe the isolation and some characteristic properties of the polysaccharide, in particular its ca2+ -binding capacity. a large-scale cultivation of the coccolithophoridae was worked out and a new procedure for isolating coccoliths was deve ... | 1976 | 1009943 |
| polysaccharide from coccoliths (caco3 biomineral). influence on crystallization of calcium oxalate monohydrate. | a polysaccharide associated with coccoliths of the marine alga emiliania huxleyi (coccoliths are elaborately shaped calcite biominerals) was isolated and its influence on the crystallization of calcium oxalate monohydrate crystals was studied. crystallization was monitored in a carefully controlled system by measuring the incorporation of 45ca tracer from a supersaturated solution into seed crystals of calcium oxalate monohydrate in the absence and in the presence of polysaccharide. the method a ... | 1986 | 3089775 |
| the role in caco3 crystallization of an acid ca2+-binding polysaccharide associated with coccoliths of emiliania huxleyi. | | 1982 | 7160380 |
| isolation and molecular phylogenetic analysis of actin-coding regions from emiliania huxleyi, a prymnesiophyte alga, by reverse transcriptase and pcr methods. | reverse transcriptase and polymerase chain reaction methods were used to amplify and clone actin cdnas from the chlorophylls a + c-containing unicellular alga, emiliania huxleyi (prymnesiophyta). actins in e. huxleyi are defined by a gene family containing at least six distinct coding regions that were derived from relatively recent gene duplications. five of the coding regions (types 1, 2, and 4-6) varied only among synonymous codons. a nonsynonomous change in a sixth coding region (type 3 acti ... | 1993 | 7687735 |
| phylogenetic diversity of ultraplankton plastid small-subunit rrna genes recovered in environmental nucleic acid samples from the pacific and atlantic coasts of the united states. | the scope of marine phytoplankton diversity is uncertain in many respects because, like bacteria, these organisms sometimes lack defining morphological characteristics and can be a challenge to grow in culture. here, we report the recovery of phylogenetically diverse plastid small-subunit (ssu) rrna gene (rdna) clones from natural plankton populations collected in the pacific ocean off the mouth of yaquina bay, oreg. (ocs clones), and from the eastern continental shelf of the united states off c ... | 1998 | 9435081 |
| long-chain alkenes of the haptophytes isochrysis galbana and emiliania huxleyi. | the major alkenes of the haptophytes isochrysis galbana (strain ccap 927/14) and emiliania huxleyi (strains ccap 920/2 and van 556) have been identified by nuclear magnetic resonance spectroscopy and by mass spectrometric analysis of their dimethyl disulfide adducts. the dominant alkene in i. galbana is (22z)-1 ,22-hentriacontadiene, with 1,24-hentriacontadiene and 1,24-tritriacontadiene present in much lower abundance; (22z)-1,22-hentriacontadiene also occurs in e. huxleyi (strain ccap 920/2), ... | 1998 | 9655378 |
| liquid-saturated hydrocarbons resulting from pyrolysis of the marine coccolithophores emiliania huxleyi and gephyrocapsa oceanica. | : two nanoplanktonic marine coccolithophores, emiliania huxleyi and gephyrocapsa oceanica, were grown at 23 degrees c with a 16-hour light and 8-hour darkness regimen. the cells were dried at room temperature and then subjected to pyrolysis at 100 degrees to 500 degrees c under anoxygenic conditions to produce hydrocarbons. temperature-dependent profiles of the liquid-saturated hydrocarbons (saturates) produced during pyrolysis were very similar for the two strains, although the total amount was ... | 1999 | 10489410 |
| the impact of uv-b radiation and different par intensities on growth, uptake of 14c, excretion of doc, cell volume, and pigmentation in the marine prymnesiophyte, emiliania huxleyi. | the impact of uv-b radiation (280-320 nm) and different par (400-700 nm) intensities on growth, uptake of 14c, excretion of doc, cell volume, and pigmentation in the marine prymnesiophyte, emiliania huxleyi2.7 kj m(-2) uv-b(be), changes in incorporation and excretion rate of 14c, and indications of dna damage (in the form of termination of cell division and enlarged cell volume) were observed. since the uv-b doses used are representative of uv-b doses in the top layer of clear ocean water and e. ... | 2000 | 10727690 |
| ingestion, faecal pellet and egg production rates of calanus helgolandicus feeding coccolithophorid versus non-coccolithophorid diets. | ingestion rates, faecal pellet and egg production were obtained in laboratory experiments with females of the copepod calanus helgolandicus collected from the english channel in november 1994. five different algal monocultures were used as food: prorocentrum micans (30 µm esd), thalassiosira weissflogii (13 µm esd), dunaliella tertiolecta (7 µm esd), emiliania huxleyi (5 µm esd) and coccolithus pelagicus (14 µm esd). results obtained suggest the low ingestion efficiency of the copepod when feedi ... | 2000 | 10771305 |
| the effect of growth temperature on the long-chain alkenes composition in the marine coccolithophorid emiliania huxleyi. | the hydrocarbon fraction of a pure culture of emiliania huxleyi, composed of a mixture of c31, c33, c37 and c38 polyunsaturated n-alkenes, appeared strongly dependent on the growth temperature of the alga between 8 degrees c and 25 degrees c. the total hydrocarbon content increased linearly with decreasing temperatures. c37 and c38 alkenes (which accounted for more than 90% of the total hydrocarbons) showed distinct changes in distribution compared to c31 and c33 alkenes, suggesting different bi ... | 2000 | 10897480 |
| reduced calcification of marine plankton in response to increased atmospheric co2. | the formation of calcareous skeletons by marine planktonic organisms and their subsequent sinking to depth generates a continuous rain of calcium carbonate to the deep ocean and underlying sediments. this is important in regulating marine carbon cycling and ocean-atmosphere co2 exchange. the present rise in atmospheric co2 levels causes significant changes in surface ocean ph and carbonate chemistry. such changes have been shown to slow down calcification in corals and coralline macroalgae, but ... | 2000 | 11014189 |
| visible light-dependent degradation of long-chain alkenes in killed cells of emiliania huxleyi and nannochloropsis salina. | photosensitized degradation rates of phytoplanktonic n-alkenes under visible light exposure were determined in laboratory experiments. killed cells of emiliania huxleyi and nannochloropsis salina were used as source of biogenic alkenes. in e. huxleyi killed cells, minor c31 and c33 n-alkenes were strongly photodegraded, while the major c37 and c38 n-alkenes appeared particularly recalcitrant towards photochemical processes. this particular photochemical recalcitrance has been attributed to the c ... | 2001 | 11314952 |
| adsorption and uptake of cu by emiliania huxleyi in natural seawater. | short-term kinetic experiments, carried out in natural coastal seawater (with predetermined background levels of trace metals and organic ligands, l) enriched with nitrate and phosphate, demonstrated that emiliania huxleyi was able to uptake cu very quickly. after 10 min of exposure (background cu level in the inoculated cells: [cu]total cellular = 9.3 x 10(-17) mol cell-1, [cu]intracellular = 8.4 x 10(-17) mol cell-1, and [cu]extracellular = 1.0 x 10(-17) mol cell-1) to a natural seawater which ... | 2001 | 11351721 |
| induction of phase variation events in the life cycle of the marine coccolithophorid emiliania huxleyi. | emiliania huxleyi is a unicellular marine alga that is considered to be the world's major producer of calcite. the life cycle of this alga is complex and is distinguished by its ability to synthesize exquisitely sculptured calcium carbonate cell coverings known as coccoliths. these structures have been targeted by materials scientists for applications relating to the chemistry of biomedical materials, robust membranes for high-temperature separation technology, lightweight ceramics, and semicond ... | 2001 | 11525973 |
| biomineralization in coccolithophores. | unicellular marine algae known as coccolithophores are potentially important organisms for the study of gravitational effects on biomineralization. the cells are easily cultured under low maintenance conditions and produce intricately sculpted calcite scales known as coccoliths in specialized golgi-derived vesicles. many mutants are available with different types of mineral defects ranging from the complete absence of mineral to the presence of mineral with orientational, morphological, number ... | 1999 | 11541783 |
| bioaccumulation of 137cs and 57co by five marine phytoplankton species. | under controlled laboratory conditions, we have examined the bioaccumulation of 137cs and 57co in three prymnesiophytes, the coccolithophorid emiliania huxleyi and the noncalcareous species isochrysis galbana and phaeocystis globosa, and two diatoms skeletonema costatum and thalassiosira pseudonana. we measured the uptake in growing and non-growing cells and determined concentration factors on both volume and dry weight bases. for uptake of 57co in non-growing cells, volume concentration factors ... | 2001 | 11720372 |
| influence of n-2-hydroxyethylpiperazine-n'-2-ethanesulfonic acid ph buffer on the biological response of marine algae. | the n-2-hydroxyethylpiperazine-n'-2-ethanesulfonic acid (hepes) is extensively used as ph buffer in culture media for testing chemicals. however, this study demonstrates that 0.01 m hepes significantly reduces the rate of cu, pb, and cd binding to porphyra spp. and enteromorpha spp. marine macroalgae. the hepes also decreased the accumulation of cu, pb, and cd but not hg by these macroalgae. both the extracellular adsorption and the intracellular uptake of the metals were influenced by hepes to ... | 2002 | 11837230 |
| coccolithovirus (phycodnaviridae): characterisation of a new large dsdna algal virus that infects emiliana huxleyi. | emiliania huxleyi-specific viruses ( ehv) were isolated from e. huxleyi blooms off the coast of plymouth, uk, in july 1999 and july/august 2001, and from an e. huxleyi bloom induced during a mesocosm experiment in a fjord off bergen, norway, during june 2000. transmission electron microscopy revealed that all 10 virus isolates are 170-200 nm in diameter with an icosahedral symmetry. their density is approximately 1.2 in cscl gradients and they have large double stranded dna genomes approximately ... | 2002 | 12209309 |
| design and testing of its probes for distinguishing phaeocystis species. | oligonucleotide probes provide rapid, easy identification of species difficult to identify by more traditional means, e.g. light microscopy. phaeocystis is a difficult genus to identify as a unicell and thus presents a good candidate for probe development. hybridisation using pcr products or cell lysates rather than whole cells as targets provides access to more highly variable regions of the genome, such as non-coding spacer regions of the ribosomal operon for detection of fine scale molecular ... | 2002 | 12389816 |
| optical modeling and measurements of a coccolithophore bloom. | blooms of the phytoplankton coccolithophorid emiliania huxleyi can cause significant changes to both the inherent and the apparent optical properties within an oceanic column. measurements made within such a bloom off the southwestern coast of england during july 1999 are reported. the multiple scattering properties of the bloom prevented accurate retrieval of absorption (a) and attenuation (c) coefficients with a wetlabs ac-9. upwelling radiance measurements were similarly affected by the bloom ... | 2002 | 12510938 |
| parameterization and analysis of the optical absorption and scattering coefficients in a western norwegian fjord: a case ii water study. | based on statistical analyses of optical properties measured during a whole year of monthly cruises in a norwegian fjord, we constructed a two-component model for the absorption and scattering coefficients for visible light. the input to the model is the concentrations of yellow substance and chlorophyll a. because of the presence of a significant amount of nonalgal particles in coastal water, we assume that the absorption and scattering coefficients approach constant background values when the ... | 2003 | 12617202 |
| comparison of the response of three microalgae species exposed to elutriates of estuarine sediments based on growth and chemical speciation. | the elutriate sediment toxicity test (estt) provides a measure of the amount of a substance that is exchanged between the sediment and the aqueous phase during resuspension processes such as floods or dredging operations. this study used estt with two complementary aims: a comparison of the elutriates of two estuarine sediments (anaerobic muddy [a] and aerobic sandy [b]) in terms of toxicity and a comparison of the response of three different microalgae (emiliania huxleyi (coccolithophore), duna ... | 2003 | 12627645 |
| virus succession observed during an emiliania huxleyi bloom. | denaturing gradient gel electrophoresis was used as a molecular tool to determine the diversity and to monitor population dynamics of viruses that infect the globally important coccolithophorid emiliania huxleyi. we exploited variations in the major capsid protein gene from e. huxleyi-specific viruses to monitor their genetic diversity during an e. huxleyi bloom in a mesocosm experiment off western norway. we reveal that, despite the presence of several virus genotypes at the start of an e. huxl ... | 2003 | 12732512 |
| potential and limitations of sr/ca ratios in coccolith carbonate: new perspectives from cultures and monospecific samples from sediments. | the sr/ca ratio of coccoliths was recently proposed as a potential indicator of past growth rates of coccolithophorids, marine algae, which play key roles in both the global carbonate and carbon cycles. we synthesize calibrations of this proxy through laboratory culture studies and analysis of monospecific coccolith assemblages from surface sediments. cultures of coccolithophorids helicosphaera carteri, syracosphaera pulchra and algirospira robusta confirm a 1-2% increase in sr/ca per degrees c ... | 2002 | 12804301 |
| semi-empirical correction algorithm for ac-9 measurements in a coccolithophore bloom. | values for the coefficients of absorption (a) and attenuation (c) obtained from ac-9 measurements in coccolithophore blooms do not provide satisfactory inputs for radiance transfer models. we have therefore modified the standard ac-9 scattering correction algorithm by including an extra term, f(lambda, lambda(r)), which allows for possible wavelength dependence in the scattering phase function. we estimated the magnitude of f(lambda, lambda(r)), which is unity in the standard algorithm, by adjus ... | 2003 | 12921287 |
| characterization of nadh: nitrate reductase from the coccolithophorid emiliania huxleyi (lohman) hay & mohler (haptophyceae). | nitrate reductase was purified from and characterized in a bloom-forming unicellular calcifying alga, emiliania huxleyi (haptophyceae). the molecular masses of the native form and the subunit were 514 and 85 kda, respectively, showing that the enzyme is a hexamer composed of 6 homologous subunits. the km values for nadh and no3- were 40 microm and 104 microm, respectively. activity of the reduction of nitrate was very high with reduced methylviologen and nadh, but no activity was observed with n ... | 2003 | 12925915 |
| regulation of caco(3) formation in coccolithophores. | coccolithophores impact the ocean carbon cycle principally through the generation of co(2) during caco(3) production. coccolithophore biomineralization has been examined most extensively in pleurochrysis carterae and emiliania huxleyi both of which produce mineralized scales-coccoliths-composed of elaborate calcite crystals attached to an underlying organic base plate. calcification of preformed base plates is mediated by acidic polysaccharides and occurs in golgi-derived structures known as min ... | 2003 | 14662299 |
| physiological regulation of carbon fixation in the photosynthesis and calcification of coccolithophorids. | emiliania huxleyi and gephyrocapsa oceanica are the predominant coccolithophorid species that produce blooms in the ocean and affect the global environment. these species are capable of carbon fixation by both photosynthesis for organic matter production and by intracellular calcification for coccolith production. both processes were strongly affected by the nutrient status in a laboratory culture. the coccolith production was stimulated by the addition of a high concentration of sodium bicarbon ... | 2003 | 14662302 |
| analysis of expressed sequence tags from calcifying cells of marine coccolithophorid (emiliania huxleyi). | an expressed sequence tag (est) approach was used to investigate gene expression in the unicelluar marine alga emiliania huxleyi. we randomly selected 3000 est sequences from a cdna library of transcripts expressed under conditions promoting coccolithogenesis. cluster analysis and contig assembly resulted in a unigene set of approximately 1523 ests. only 36% of the unique sequences exhibited significant homology to sequences in genbank. of particular interest were the numerous transcripts with h ... | 2004 | 15136914 |
| the complete mitochondrial genome sequence of the haptophyte emiliania huxleyi and its relation to heterokonts. | the complete nucleotide sequence of the mitochondrial genome of emiliania huxleyi (haptophyta) was determined. e. huxleyi is the most abundant coccolithophorid, key in many marine ecosystems, and plays a vital role in the global carbon cycle. the mitochondrial genome contains genes encoding three subunits of cytochrome c oxidase, apocytochrome b, seven subunits of the nadh dehydrogenase complex, two atpase subunits, two ribosomal rnas, 25 trnas and five ribosomal proteins. one potentially functi ... | 2004 | 15141941 |
| the complete mitochondrial genome sequence of the haptophyte emiliania huxleyi and its relation to heterokonts (supplement). | | 2004 | 15141947 |
| alkenone and alkenoic acid compositions of the membrane fractions of emiliania huxleyi. | the lipid classes and unsaturation ratios of long-chain alkenones (nc37-c39), related alkyl alkenoate compounds (nc37-c38) and alkenoic acids (nc14-c22) were determined in isolated membrane and organelle fractions of emiliania huxleyi. the percentage distribution of these compounds was predominantly high in the endoplasmic reticulum (er) and coccolith-producing compartment (cpc)-rich membrane fraction, although alkenones and alkenoates could be detected in all membrane fractions. in particular, ... | 2004 | 15184016 |
| sediment quality in the douro river estuary based on trace metal contents, macrobenthic community and elutriate sediment toxicity test (estt). | the aim of this study was to evaluate the sediment quality in the mesotidal douro river estuarine environment, in order to identify areas where sediment contamination could cause ecosystem degradation. samples were obtained in five locations and sediment characterised for grain size, total organic matter, total-recoverable metals (al, fe, cu, pb, cr, ni, cd, zn and mn), as well as acid volatile sulfide (avs) and simultaneously extracted metals (sem). in situ effects were evaluated by examining t ... | 2004 | 15237288 |
| effect of trace metal availability on coccolithophorid calcification. | the deposition of atmospheric dust into the ocean has varied considerably over geological time. because some of the trace metals contained in dust are essential plant nutrients which can limit phytoplankton growth in parts of the ocean, it has been suggested that variations in dust supply to the surface ocean might influence primary production. whereas the role of trace metal availability in photosynthetic carbon fixation has received considerable attention, its effect on biogenic calcification ... | 2004 | 15295599 |
| structural and physiological effects of calcium and magnesium in emiliania huxleyi (lohmann) hay and mohler. | in organisms which perform both photosynthesis and calcification, the fact that calcification proceeds faster in the light than in the dark has led to the long-established view that photosynthesis and calcification are closely coupled. it is now clear that calcification does not promote photosynthesis, but an enhancement of calcification by photosynthesis could still explain why calcification is faster in the light. to test this, the kinetics of the two processes were monitored over a wide range ... | 2004 | 15522779 |
| bioconcentration mechanism of selenium by a coccolithophorid, emiliania huxleyi. | we investigated the uptake and bioconcentration of the essential element selenium by a coccolithophorid, emiliania huxleyi, using [75se]selenite. the time course of 75se uptake showed a biphasic pattern, namely a primary phase and a subsequent secondary phase. the primary and secondary phases are due to a rapid selenite uptake process that attained a stationary level within 2 min and a slow se-accumulation process that continued at a constant rate for 4 h or longer, respectively. kinetic analysi ... | 2004 | 15564527 |
| comparison by pam fluorometry of photosynthetic activity of nine marine phytoplankton grown under identical conditions. | the photosynthetic activity of marine phytoplankton from five algal classes (phaeodactylum tricornutum, skeletonema costatum, thalassiosira oceanica, thalassiosira weissflogii, dunaliella tertiolecta, mantoniella squamata, emiliania huxleyi, pavlova lutheri and heterosigma akashiwo) was investigated under identical growth conditions to determine interspecies differences. primary photochemistry and electron transport capacity of individual species were examined by pulse amplitude-modulated (pam) ... | 2005 | 15686444 |
| a novel eukaryotic selenoprotein in the haptophyte alga emiliania huxleyi. | the diversity of selenoproteins raises the question of why many life forms require selenium. especially in photosynthetic organisms, the biochemical basis for the requirement for selenium is unclear because there is little information on selenoproteins. we found six selenium-containing proteins in a haptophyte alga, emiliania huxleyi, which requires selenium for growth. the 27-kda protein ehsep2 was isolated, and its cdna was cloned. the deduced amino acid sequence revealed that ehsep2 is homolo ... | 2005 | 15743763 |
| low temperature stimulates cell enlargement and intracellular calcification of coccolithophorids. | temperature effect on growth, cell size, calcium uptake activity, coccolith production was studied in coccolith-producing haptophytes, emiliania huxleyi (lohmann) hay & mohler (strain eh2) and gephyrocapsa oceanica kamptner (strain go1) (coccolithophorales, prymnesiophyceae). e. huxleyi grew at a wider temperature range (10 degrees-25 degrees c), while g. oceanica growth was limited to warmer temperatures (20 degrees-25 degrees c). cell size was inversely correlated with temperature. at low temp ... | 2005 | 15782289 |
| short-term physiologic effects of mechanical flow sorting and the becton-dickinson cell concentrator in cultures of the marine phytoflagellata emiliania huxleyi and micromonas pusilla. | in contrast to large, high-efficiency cytometers, mechanically sorting benchtop instruments provide a feasible alternative for shipboard cell sorting of oceanic microbial communities. however, sorting efficiency of these instruments is constrained by their maximum sorting rate of approximately 300 cells/s and by constant dilution of sorted samples by sheath flow. these factors often render too low sorted cell concentrations for postsorting experiments of oceanic phytoplankton populations of low ... | 2005 | 15791646 |
| suppressive subtractive hybridization of and differences in gene expression content of calcifying and noncalcifying cultures of emiliania huxleyi strain 1516. | the marine coccolithophorid emiliania huxleyi is a cosmopolitan alga intensely studied in relation to global carbon cycling, biogeochemistry, marine ecology, and biomineralization processes. the biomineralization capabilities of coccolithophorids have attracted the attention of scientists interested in exploiting this ability for the development of materials science and biomedical and biotechnological applications. although it has been well documented that biomineralization in e. huxleyi is prom ... | 2005 | 15870347 |
| complete genome sequence and lytic phase transcription profile of a coccolithovirus. | the genus coccolithovirus is a recently discovered group of viruses that infect the globally important marine calcifying microalga emiliania huxleyi. among the 472 predicted genes of the 407,339-base pair genome are a variety of unexpected genes, most notably those involved in biosynthesis of ceramide, a sphingolipid known to induce apoptosis. uniquely for algal viruses, it also contains six rna polymerase subunits and a novel promoter, suggesting this virus encodes its own transcription machine ... | 2005 | 16099989 |
| evolutionary history of the coccolithoviridae. | we recently determined the genome sequence of the coccolithoviridae strain emiliania huxleyi virus 86 (ehv-86), a giant double-stranded dna (dsdna) algal virus from the family phycodnaviridae that infects the marine coccolithophorid e. huxleyi. here, we determine the phylogenetic relationship between ehv-86 and other large dsdna viruses. twenty-five core genes common to nuclear-cytoplasmic large dsdna virus genomes were identified in the ehv-86 genome; sequence from eight of these genes were use ... | 2006 | 16151186 |
| preliminary characterisation of repeat families in the genome of ehv-86, a giant algal virus that infects the marine microalga emiliania huxleyi. | ehv-86 is a large double stranded dna virus with a 407,339 base pair circular genome that infects the globally important microalga emiliania huxleyi. it belongs to a new genus of viruses termed the coccolithoviridae within the algal virus family phycodnaviridae. by plotting the ehv-86 genome against itself in a dot-plot analysis we revealed three families of distinctly different repeat sequences throughout its genome, designated family a, b and c. family a repeats are non-coding, found immediate ... | 2006 | 16195784 |
| massive light-dependent cycling of inorganic carbon between oxygenic photosynthetic microorganisms and their surroundings. | membrane inlet mass spectrometry indicated massive light-dependent cycling of inorganic carbon between the medium and the cells of various phytoplankton species representing the main groups of aquatic primary producers. these included diatoms, symbiotic and free living dinoflagellates, a coccolithophorid, a green alga and filamentous and single cell cyanobacteria. these organisms could maintain an ambient co(2) concentration substantially above or below that expected at chemical equilibrium with ... | 2003 | 16228368 |
| the complete plastid genome sequence of the haptophyte emiliania huxleyi: a comparison to other plastid genomes. | the complete nucleotide sequence of the plastid genome of the haptophyte emiliania huxleyi has been determined. e. huxleyi is the most abundant coccolithophorid and has a key role in the carbon cycle. it is also implicated in the production of dimethylsulphide (dms), which is involved in cloud nucleation and may affect the global climate. here, we report the plastid genome sequence of this ecologically and economically important species and compare its gene content and arrangement to other known ... | 2005 | 16303746 |
| utilization of organic nitrogen sources by two phytoplankton species and a bacterial isolate in pure and mixed cultures. | algal production of dissolved organic carbon and the regeneration of nutrients from dissolved organic carbon by bacteria are important aspects of nutrient cycling in the sea, especially when inorganic nitrogen is limiting. dissolved free amino acids are a major carbon source for bacteria and can be used by phytoplankton as a nitrogen source. we examined the interactions between the phytoplankton species emiliania huxleyi and thalassiosira pseudonana and a bacterial isolate from the north sea. th ... | 1994 | 16349256 |
| phylogenomic analysis identifies red algal genes of endosymbiotic origin in the chromalveolates. | endosymbiosis has spread photosynthesis to many branches of the eukaryotic tree; however, the history of photosynthetic organelle (plastid) gain and loss remains controversial. fortuitously, endosymbiosis may leave a genomic footprint through the transfer of endosymbiont genes to the "host" nucleus (endosymbiotic gene transfer, egt). egt can be detected through comparison of host genomes to uncover the history of past plastid acquisitions. here we focus on a lineage of chlorophyll c-containing a ... | 2006 | 16357039 |
| long serial analysis of gene expression for gene discovery and transcriptome profiling in the widespread marine coccolithophore emiliania huxleyi. | the abundant and widespread coccolithophore emiliania huxleyi plays an important role in mediating co2 exchange between the ocean and the atmosphere through its impact on marine photosynthesis and calcification. here, we use long serial analysis of gene expression (sage) to identify e. huxleyi genes responsive to nitrogen (n) or phosphorus (p) starvation. long sage is an elegant approach for examining quantitative and comprehensive gene expression patterns without a priori knowledge of gene sequ ... | 2006 | 16391051 |
| rate variation as a function of gene origin in plastid-derived genes of peridinin-containing dinoflagellates. | peridinin-pigmented dinoflagellates contain secondary plastids that seem to have undergone more nearly complete plastid genome reduction than other eukaryotes. many typically plastid-encoded genes appear to have been transferred to the nucleus, with a few remaining genes found on minicircles. to understand better the evolution of the dinoflagellate plastid, four categories of plastid-associated genes in dinoflagellates were defined based on their history of transfer and evaluated for rate of seq ... | 2006 | 16408243 |
| characterization of a nitrogen-regulated protein identified by cell surface biotinylation of a marine phytoplankton. | the biotinylating reagent succinimidyl 6-(biotinamido)hexanoate was used to label the cell surfaces of the cosmopolitan, marine, eukaryotic microorganism emiliania huxleyi under different growth conditions. proteins characteristic of different nutrient conditions could be identified. in particular, a nitrogen-regulated protein, nrp1, has an 82-kda subunit that is present under nitrogen limitation and during growth on urea. it is absent under phosphate limitation or during exponential growth on n ... | 1995 | 16535120 |
| reassessment of the structural composition of the alkenone distributions in natural environments using an improved method for double bond location based on gc-ms analysis of cyclopropylimines. | the usefulness of n-propyl-, iso-propyl-, and cyclopropylamines for the location of double bonds positions in c37-c40 alkenones after formation of imino derivatives has been evaluated. cyclopropylamine is the best reagent for its high reaction yields, gc retention time difference between derivatives and precursor compounds, and absence of generation of byproducts. the use of this c3 amine involves higher sensitivity and ease of application than previously reported c5 amines. examination of a lar ... | 2006 | 16540339 |
| genome comparison of two coccolithoviruses. | the coccolithoviridae is a recently discovered family of viruses that infect the marine coccolithophorid emiliania huxleyi. following on from the sequencing of the type strain ehv-86, we have sequenced a second strain, ehv-163. | 2006 | 16553948 |
| locus-specific gene expression pattern suggests a unique propagation strategy for a giant algal virus. | emiliania huxleyi virus strain 86 is the largest algal virus sequenced to date and is unique among the phycodnaviridae since its genome is predicted to contain six rna polymerase subunit genes. we have used a virus microarray to profile the temporal transcription strategy of this unusual virus during infection. there are two distinct transcription phases to the infection process. the primary phase is dominated by a group of coding sequences (cdss) expressed by 1 h postinfection that are localize ... | 2006 | 16840348 |
| identification and preliminary characterization of two cdnas encoding unique carbonic anhydrases from the marine alga emiliania huxleyi. | marine coccolithophorid algae are thought to play a significant role in carbon cycling due to their ability to incorporate dissolved inorganic carbon (dic) into both calcite and photosynthetic products. among coccolithophorids, emiliania huxleyi is the most prolific, forming massive blooms that affect the global environment. in addition to its ecological importance, the elaborate calcite structures (coccoliths) are being investigated for the design of potential materials for science and biotechn ... | 2006 | 16885304 |
| cdna microarrays as a tool for identification of biomineralization proteins in the coccolithophorid emiliania huxleyi (haptophyta). | marine unicellular coccolithophore algae produce species-specific calcite scales otherwise known as coccoliths. while the coccoliths and their elaborate architecture have attracted the attention of investigators from various scientific disciplines, our knowledge of the underpinnings of the process of biomineralization in this alga is still in its infancy. the processes of calcification and coccolithogenesis are highly regulated and likely to be complex, requiring coordinated expression of many g ... | 2006 | 16885305 |
| expression of a novel marine viral single-chain serine palmitoyltransferase and construction of yeast and mammalian single-chain chimera. | the genus coccolithovirus is a recently discovered group of viruses that infect the globally important marine calcifying microalga emiliania huxleyi. surprisingly, the viral genome contains a cluster of putative sphingolipid biosynthetic genes not found in other viral genus. to address the role of these genes in viral pathogenesis, the ehv050 gene predicted to encode a serine palmitoyltransferase (spt), the first and rate-limiting enzyme of sphingolipid biosynthesis, was expressed and characteri ... | 2006 | 17090526 |
| molecular dynamics of emiliania huxleyi and cooccurring viruses during two separate mesocosm studies. | in this study we used denaturing gradient gel electrophoresis, sequencing analysis, and analytical flow cytometry to monitor the dynamics and genetic richness of emiliania huxleyi isolates and cooccurring viruses during two mesocosm experiments in a norwegian fjord in 2000 and 2003. we exploited variations in a gene encoding a protein with calcium-binding motifs (gpa) and in the major capsid protein (mcp) gene to assess allelic and genotypic richness within e. huxleyi and e. huxleyi-specific vir ... | 2007 | 17098923 |
| chloroplast genomes of the diatoms phaeodactylum tricornutum and thalassiosira pseudonana: comparison with other plastid genomes of the red lineage. | the chloroplast genomes of the pennate diatom phaeodactylum tricornutum and the centric diatom thalassiosira pseudonana have been completely sequenced and are compared with those of other secondary plastids of the red lineage: the centric diatom odontella sinensis, the haptophyte emiliania huxleyi, and the cryptophyte guillardia theta. all five chromist genomes are compact, with small intergenic regions and no introns. the three diatom genomes are similar in gene content with 127-130 protein-cod ... | 2007 | 17252281 |
| free radical oxidation (autoxidation) of alkenones and other lipids in cells of emiliania huxleyi. | cells of the coccolithophorid emiliania huxleyi strain cs-57 grown under an atmosphere of air+0.5% co(2) showed oxidative damage after 10 days growth with concomitant and major changes to the lipid composition. the fatty acid profile was strongly altered and lacked appreciable amounts of the polyunsaturated fatty acids (pufa: c(18:5), c(18:3) and c(22:6)) typical of healthy cells. oxidation products of these pufa could not be detected, but monounsaturated fatty acids proved to be good indicators ... | 2007 | 17258251 |
| isolation of methylophaga spp. from marine dimethylsulfide-degrading enrichment cultures and identification of polypeptides induced during growth on dimethylsulfide. | dimethylsulfide (dms)-degrading enrichment cultures were established from samples of coastal seawater, nonaxenic emiliania huxleyi cultures, and mixed marine methyl halide-degrading enrichment cultures. bacterial populations from a broad phylogenetic range were identified in the mixed dms-degrading enrichment cultures by denaturing gradient gel electrophoresis (dgge). sequences of dominant dgge bands were similar to those of members of the genera methylophaga and alcanivorax. several closely rel ... | 2007 | 17322322 |
| an efficient method for isolating individual long-chain alkenones for compound-specific hydrogen isotope analysis. | hydrogen isotope ratios (2h/h or d/h) of long-chain unsaturated ketones (alkenones) preserved in lake and marine sediments hold great promise for paleoclimate studies. however, compound-specific hydrogen isotope analysis of individual alkenones has not been possible due to chromatographic coelution of alkenones with the same carbon chain length but different numbers of double bonds. published studies have only reported the deltad values of the mixture of coeluting alkenones. we developed an effi ... | 2007 | 17391004 |
| viral activation and recruitment of metacaspases in the unicellular coccolithophore, emiliania huxleyi. | lytic viral infection and programmed cell death (pcd) are thought to represent two distinct death mechanisms in phytoplankton, unicellular photoautotrophs that drift with ocean currents. here, we demonstrate an interaction between autocatalytic pcd and lytic viral infection in the cosmopolitan coccolithophorid, emiliania huxleyi. successful infection of e. huxleyi strain 374 with a lytic virus, ehv1, resulted in rapid internal degradation of cellular components, a dramatic reduction in the photo ... | 2007 | 17392426 |
| phylogenomic analysis supports the monophyly of cryptophytes and haptophytes and the association of rhizaria with chromalveolates. | here we use phylogenomics with expressed sequence tag (est) data from the ecologically important coccolithophore-forming alga emiliania huxleyi and the plastid-lacking cryptophyte goniomonas cf. pacifica to establish their phylogenetic positions in the eukaryotic tree. haptophytes and cryptophytes are members of the putative eukaryotic supergroup chromalveolata (chromists [cryptophytes, haptophytes, stramenopiles] and alveolates [apicomplexans, ciliates, and dinoflagellates]). the chromalveolate ... | 2007 | 17488740 |
| novel insights into evolution of protistan polyketide synthases through phylogenomic analysis. | polyketide synthase (pks) enzymes are large multi-domain complexes that structurally and functionally resemble the fatty acid synthases involved in lipid metabolism. polyketide biosynthesis of secondary metabolites and hence functional pks genes are widespread among bacteria, fungi and streptophytes, but the type i was formerly known only from bacteria and fungi. recently type i pks genes were also uncovered in the genomes of some alveolate protists. here we show that the newly sequenced genomes ... | 2008 | 17931970 |
| pilot study of an est approach of the coccolithophorid emiliania huxleyi during a virus infection. | blooms of the coccolithophorid emiliania huxleyi can be infected by viruses, which can lead to bloom-termination. this pilot study used an expressed sequence tag (est) approach to get a first view of gene-expression changes that occur during viral infection of e. huxleyi. cdna libraries were constructed from uninfected cultures and 6, 12, and 24 h after infection with e. huxleyi-specific virus 86 (ehv-86). from each library 60-90 ests were randomly selected and annotated manually with phylogena. ... | 2007 | 18035506 |
| particle availability controls agglutination in pelagic tintinnids in the southern ocean. | mechanisms of particle selectivity controlling agglutination within the agglomerated tintinnid genus stenosemella spp. jörgensen were studied during two iron fertilisation experiments (eisenex and eifex) conducted in the southern ocean in austral spring 2000 and late austral summer to early autumn 2004. representative sem pictures of stenosemella spp. loricae were taken on the day of fertilisation, during the middle and at the end of both experiments. whereas during eisenex particles used for ag ... | 2008 | 18082445 |
| in the grip of algal genomics. | algae are dominant primary producers on the earth and have a major impact on global productivity and biogeochemical cycling. there are still few algal genomes that have been completely characterized, and resources directed toward algal genomic sequencing are limited. however, it is also becoming evident that algae and prokaryotic picoplankton have a critical role in the fixation and sequestration of carbon, and so the interest in algal genomics is expanding. there are some algae for which full o ... | 2007 | 18161491 |
| proteomic analysis of the ehv-86 virion. | emiliania huxleyi virus 86 (ehv-86) is the type species of the genus coccolithovirus within the family phycodnaviridae. the fully sequenced 407,339 bp genome is predicted to encode 473 protein coding sequences (cdss) and is the largest phycodnaviridae sequenced to date. the majority of ehv-86 cdss exhibit no similarity to proteins in the public databases. | 2008 | 18346272 |
| development and validation of a molecular technique for the analysis of archived formalin-preserved phytoplankton samples permits retrospective assessment of emiliania huxleyi communities. | the coccolithophores, particularly the species emiliania huxleyi (lohmann) hay & mohler, account for the bulk of global calcium carbonate production and as such play a fundamental role in global co2 cycling and the carbonate chemistry of the oceans. to evaluate the response of this functional group to the effects of climate change, we undertook a feasibility study to determine whether a retrospective approach could be used on archived coccolithophore datasets. we demonstrate for the first time a ... | 2008 | 18358549 |
| screening volatile organic compounds (vocs) emissions from five marine phytoplankton species by head space gas chromatography/mass spectrometry (hs-gc/ms). | five marine cosmopolitan phytoplankton species namely; calcidiscus leptoporus, emiliania huxleyi, phaeodactylum tricornutum, chaetoceros neogracilis and dunaliella tertiolecta were screened for emissions of selected vocs using head space gas chromatography/mass spectrometry (hs-gc/ms) in single ion mode. the vocs investigated included isoprene and various halogenated compounds. among the different algae groups, the two diatoms ch. neogracilis and p. tricornutum were the strongest emitters of met ... | 2008 | 18392274 |
| phytoplankton calcification in a high-co2 world. | ocean acidification in response to rising atmospheric co2 partial pressures is widely expected to reduce calcification by marine organisms. from the mid-mesozoic, coccolithophores have been major calcium carbonate producers in the world's oceans, today accounting for about a third of the total marine caco3 production. here, we present laboratory evidence that calcification and net primary production in the coccolithophore species emiliania huxleyi are significantly increased by high co2 partial ... | 2008 | 18420926 |
| in situ observation of the internal structure and composition of biomineralized emiliania huxleyi calcite by solid-state nmr spectroscopy. | biomineralization, particularly the formation of calcium carbonate structures by organisms under ambient conditions, is of vast fundamental and applied interest. organisms finely control all aspects of the formation of the biomaterials: composition, polymorph, morphology, and macroscopic properties. while in situ molecular-level characterization of the resulting biominerals is a formidable task, solid-state magic angle spinning nmr is one of the most powerful analytical techniques for this purpo ... | 2008 | 18781749 |
| the "cheshire cat" escape strategy of the coccolithophore emiliania huxleyi in response to viral infection. | the coccolithophore emiliania huxleyi is one of the most successful eukaryotes in modern oceans. the two phases in its haplodiploid life cycle exhibit radically different phenotypes. the diploid calcified phase forms extensive blooms, which profoundly impact global biogeochemical equilibria. by contrast, the ecological role of the noncalcified haploid phase has been completely overlooked. giant phycodnaviruses (emiliania huxleyi viruses, ehvs) have been shown to infect and lyse diploid-phase cel ... | 2008 | 18824682 |
| exudates of different marine algae promote growth and mediate trace metal binding in phaeodactylum tricornutum. | phaeodactylum tricornutum was grown in filtered natural seawater enriched with nitrate, phosphate, and silicate only (control) or with exudates from itself, from emiliania huxleyi (a coccolithophore micro-alga), porphyra spp. (a red macro-alga) or enteromorpha spp. (a green macro-alga). cathodic (and anodic) stripping voltammetry (c(a)sv) were used to determine the concentrations of trace metals, both in the medium and in the algae, as well as total cu-complexing organic ligands in the medium an ... | 2008 | 18829098 |
| cold stress stimulates intracellular calcification by the coccolithophore, emiliania huxleyi (haptophyceae) under phosphate-deficient conditions. | intracellular calcification by the coccolith-producing haptophyte emiliania huxleyi (nies 837) is regulated by various environmental factors. this study focused on the relationship between cold and phosphate-deficient stresses to elucidate how those factors control coccolith production. (45)ca incorporation into coccoliths was more than 97% of the total (45)ca incorporation by whole cells. in a batch culture, orthophosphate in the medium (final concentration, 28.7 mum) was rapidly depleted withi ... | 2009 | 18830665 |
| identification and characterization of a selenoprotein, thioredoxin reductase, in a unicellular marine haptophyte alga, emiliania huxleyi. | we found six selenoproteins (ehsep1-6) in the coccolithophorid emiliania huxleyi (haptophyceae) using the (75)se radiotracer technique. previously, the most abundant selenoprotein, ehsep2, was identified as a novel selenoprotein, a protein disulfide isomerase-like protein (obata, t., and shiraiwa, y. (2005) j. biol. chem. 280, 18462-18468). the present study focused on the second abundant selenoprotein, ehsep1, in the same cells and analyzed its molecular properties and regulation of gene expres ... | 2008 | 18945673 |
| comment on "phytoplankton calcification in a high-co2 world". | iglesias-rodriguez et al. (research articles, 18 april 2008, p. 336) reported that the coccolithophore emiliania huxleyi doubles its organic matter production and calcification in response to high carbon dioxide partial pressures, contrary to previous laboratory and field studies. we argue that shortcomings in their experimental protocol compromise the interpretation of their data and the resulting conclusions. | 2008 | 19056960 |
| photosynthetic carbon assimilation in the coccolithophorid emiliania huxleyi (haptophyta): evidence for the predominant operation of the c3 cycle and the contribution of {beta}-carboxylases to the active anaplerotic reaction. | the coccolithophorid emiliania huxleyi (haptophyta) is a representative and unique marine phytoplankton species that fixes inorganic carbon by photosynthesis and calci-fication. we examined the initial process of photosynthetic carbon assimilation by analyses of metabolites, enzymes and genes. when the cells were incubated with a radioactive substrate (2.3 mm nah(14)co(3)) for 10 s under illumination, 70% of the (14)c was incorporated into the 80% methanol-soluble fraction. eighty-five and 15% o ... | 2009 | 19109302 |
| light-dependent transcriptional regulation of genes of biogeochemical interest in the diploid and haploid life cycle stages of emiliania huxleyi. | the expression of genes of biogeochemical interest in calcifying and noncalcifying life stages of the coccolithophore emiliania huxleyi was investigated. transcripts potentially involved in calcification were tested through a light-dark cycle. these transcripts were more abundant in calcifying cells and were upregulated in the light. their application as potential candidates for in situ biogeochemical proxies is also suggested. | 2009 | 19304825 |
| horizontal gene transfer of an entire metabolic pathway between a eukaryotic alga and its dna virus. | interactions between viruses and phytoplankton, the main primary producers in the oceans, affect global biogeochemical cycles and climate. recent studies are increasingly revealing possible cases of gene transfers between cyanobacteria and phages, which might have played significant roles in the evolution of cyanobacteria/phage systems. however, little has been documented about the occurrence of horizontal gene transfer in eukaryotic phytoplankton/virus systems. here we report phylogenetic evide ... | 2009 | 19451591 |
| a unicellular algal virus, emiliania huxleyi virus 86, exploits an animal-like infection strategy. | emiliania huxleyi virus 86 (ehv-86) belongs to the family phycodnaviridae, a group of viruses that infect a wide range of freshwater and marine eukaryotic algae. phycodnaviridae is one of the five families that belong to a large and phylogenetically diverse group of viruses known as nucleocytoplasmic large dsdna viruses (ncldvs). to date, our understanding of algal ncldv entry is based on the entry mechanisms of members of the genera chlorovirus and phaeovirus, both of which consist of non-envel ... | 2009 | 19474246 |
| novel virus dynamics in an emiliania huxleyi bloom. | diel studies of an emiliania huxleyi bloom within a mesocosm revealed a highly dynamic associated viral community, changing on small times scales of hours. | 2009 | 19495423 |
| physiological regulation of coccolith polysaccharide production by phosphate availability in the coccolithophorid emiliania huxleyi. | coccoliths of the coccolithophorid emiliania huxleyi are calcified biomineral scales composed of calcium carbonate and coccolith polysaccharide (cps). coccolith production is regulated by inorganic phosphate (p(i)) availability, but no information currently exists on how this process occurs. in this study cp was experimentally characterized by hplc analysis as an acid polysaccharide of mannose, galacturonic acid, xylose and rhamnose. both calcification (estimated from 45ca uptake) and cp product ... | 2009 | 19587028 |
| host-virus shift of the sphingolipid pathway along an emiliania huxleyi bloom: survival of the fattest. | the interactions between viruses and phytoplankton play a key role in shaping the ecological and evolutionary dynamics of oceanic ecosystems. one of the most fascinating examples of horizontal gene transfer between a eukaryotic host and its virus is a de novo sphingolipid biosynthesis pathway (sbp) found in the genomes of both emiliania huxleyi and its coccolithovirus ehv-86. here, we focus on a natural e. huxleyi/coccolithovirus system off the coast of norway and investigate the dynamics of hos ... | 2009 | 19638172 |
| effects of ultraviolet radiation on marine virus-phytoplankton interactions. | abstract ambient ultraviolet radiation (uvr) is harmful to many biological systems and increased uvr, due to a reduced ozone layer, may have many unforeseen consequences. viruses are the most abundant biological particles in the sea and are thought to play an important role in the structure and functioning of aquatic ecosystems. although an increasing number of studies have been published during the last 15 years, aquatic viral ecology is still in its infancy and little is known about the effect ... | 2003 | 19719609 |
| transcriptome analysis of functional differentiation between haploid and diploid cells of emiliania huxleyi, a globally significant photosynthetic calcifying cell. | eukaryotes are classified as either haplontic, diplontic, or haplo-diplontic, depending on which ploidy levels undergo mitotic cell division in the life cycle. emiliania huxleyi is one of the most abundant phytoplankton species in the ocean, playing an important role in global carbon fluxes, and represents haptophytes, an enigmatic group of unicellular organisms that diverged early in eukaryotic evolution. this species is haplo-diplontic. little is known about the haploid cells, but they have be ... | 2009 | 19832986 |
| light scattering by coccoliths detached from emiliania huxleyi. | we used in situ radiance/irradiance profiles to retrieve profiles of the spectral backscattering coefficient for all particles in an e. huxleyi coccolithophore bloom off the coast of plymouth, uk. at high detached coccolith concentrations the spectra of backscattering all showed a minimum near approximately 550 to 600 nm. using flow cytometry estimates of the detached coccolith concentration, and assuming all of the backscattering (over and above the backscattering by the water itself) was due t ... | 2009 | 19881674 |
| viral glycosphingolipids induce lytic infection and cell death in marine phytoplankton. | marine viruses that infect phytoplankton are recognized as a major ecological and evolutionary driving force, shaping community structure and nutrient cycling in the marine environment. little is known about the signal transduction pathways mediating viral infection. we show that viral glycosphingolipids regulate infection of emiliania huxleyi, a cosmopolitan coccolithophore that plays a major role in the global carbon cycle. these sphingolipids derive from an unprecedented cluster of biosynthet ... | 2009 | 19892986 |
| selenium utilization strategy by microalgae. | the diversity of selenoproteins raises the question of why so many life forms require selenium. selenoproteins are found in bacteria, archaea, and many eukaryotes. in photosynthetic microorganisms, the essential requirement for selenium has been reported in 33 species belonging to six phyla, although its biochemical significance is still unclear. according to genome databases, 20 species are defined as selenoprotein-producing organisms, including five photosynthetic organisms. in a marine coccol ... | 2009 | 20032866 |
| enrichment of oxygen heavy isotopes during photosynthesis in phytoplankton. | some of the oxygen produced during oxygenic photosynthesis is consumed but little is known about the extent of the processes involved. we measured the (17)o/(16)o and (18)o/(16)o ratios in o(2) produced by certain marine and freshwater phytoplankton representing important groups of primary producers. when the cells were performing photosynthesis under very low dissolved oxygen concentrations (< 3 μm), we observed significant enrichment in both (18)o and (17)o with respect to the substrate water. ... | 2010 | 20054712 |
| comparative sequence analysis of cp12, a small protein involved in the formation of a calvin cycle complex in photosynthetic organisms. | cp12, a small intrinsically unstructured protein, plays an important role in the regulation of the calvin cycle by forming a complex with phosphoribulokinase (prk) and glyceraldehyde-3-phosphate dehydrogenase (gapdh). an extensive search in databases revealed 129 protein sequences from, higher plants, mosses and liverworts, different groups of eukaryotic algae and cyanobacteria. cp12 was identified throughout the plantae, apart from in the prasinophyceae. within the chromalveolata, two putative ... | 2010 | 20224939 |
| effect of coccolith polysaccharides isolated from the coccolithophorid, emiliania huxleyi, on calcite crystal formation in in vitro caco3 crystallization. | marine coccolithophorids (haptophyceae) produce calcified scales "coccoliths" which are composed of caco(3) and coccolith polysaccharides (cp) in the coccolith vesicles. cp was previously reported to be composed of uronic acids and sulfated residues, etc. attached to the polymannose main chain. although anionic polymers are generally known to play key roles in biomineralization process, there is no experimental data how cp contributes to calcite crystal formation in the coccolithophorids. cp use ... | 2011 | 20336339 |
| potential alteration of u37k' paleothermometer due to selective degradation of alkenones by marine bacteria isolated from the haptophyte emiliania huxleyi. | the unsaturation ratio of c(37) alkenones (u(37)(k')) produced by haptophyte microalgae such as emiliania huxleyi is often used as proxy for past sea surface temperature. in this study, 29 bacterial strains were isolated from cultures of the strain e. huxleyi twp1. among alkenone-degrading isolates, the strain dietzia maris sp. s1 appeared to be able to selectively degrade alkenones leading to increases in the palaeoenvironmental proxy u(37)(k') by +0.05 to +0.10 units, which is equivalent to th ... | 2010 | 20491919 |
| influence of food on the assimilation of selected metals in tropical bivalves from the new caledonia lagoon: qualitative and quantitative aspects. | the present study aimed at examining the influence of food quality and quantity on the assimilation efficiency (ae) of metals in two abundant bivalves in the new caledonia lagoon, the oyster isognomon isognomon and the clam gafrarium tumidum. bivalves were exposed via their food to the radiotracers of three metals of concern in new caledonia ((54)mn, (57)co and (65)zn) under different feeding conditions (phytoplankton species, cell density, and cell-associated metal concentration). when bivalves ... | 2010 | 20638086 |
| transcription factor families inferred from genome sequences of photosynthetic stramenopiles. | • by comparative analyses we identify lineage-specific diversity in transcription factors (tfs) from stramenopile (or heterokont) genome sequences. we compared a pennate (phaeodactylum tricornutum) and a centric diatom (thalassiosira pseudonana) with those of other stramenopiles (oomycetes, pelagophyceae, and phaeophyceae (ectocarpus siliculosus)) as well as to that of emiliania huxleyi, a haptophyte that is evolutionarily related to the stramenopiles. • we provide a detailed description of diat ... | 2010 | 20646219 |
| shotgun proteomic analysis of emiliania huxleyi, a marine phytoplankton species of major biogeochemical importance. | emiliania huxleyi is a unicellular marine phytoplankton species known to play a significant role in global biogeochemistry. through the dual roles of photosynthesis and production of calcium carbonate (calcification), carbon is transferred from the atmosphere to ocean sediments. almost nothing is known about the molecular mechanisms that control calcification, a process that is tightly regulated within the cell. to initiate proteomic studies on this important and phylogenetically remote organism ... | 2010 | 20924652 |
| viral trans-dominant manipulation of algal sphingolipids. | emiliania huxleyi is the host for the coccolithovirus (ehv), which is responsible for the demise of large oceanic blooms formed by this alga. the ehv-86 virus genome sequence has identified several genes apparently involved in sphingolipid metabolism. recently, an unusual glucosylceramide from e. huxleyi infected with ehv-86 was isolated, implicating sphingolipids in the lysis of this alga. however, the ehv-86-encoded genes contain only a subset of the activities required to generate the novel s ... | 2010 | 20934366 |