Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ALGAE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed1970

Biosynthesis of phytoquinones. Homogentisic acid: a precursor of plastoquinones, tocopherols and alpha-tocopherolquinone in higher plants, green algae and blue-green algae.

1. By means of (14)C tracer experiments and isotope competition experiments the roles of d-tyrosine, p-hydroxyphenylpyruvic acid, p-hydroxyphenylacetic acid, phenylacetic acid, homogentisic acid and homoarbutin (2-methylquinol 4-beta-d-glucoside) in the biosynthesis of plastoquinones, tocopherols and alpha-tocopherolquinone by maize shoots was investigated. It was established that d-tyrosine, p-hydroxyphenylpyruvic acid and homogentisic acid can all be utilized for this purpose, whereas p-hydroxyphenylacetic acid, phenylacetic acid and homoarbutin cannot. Studies on the mode of incorporation of d-tyrosine, p-hydroxyphenylpyruvic acid and homogentisic acid showed that their nuclear carbon atoms and the side-chain carbon atom adjacent to the nucleus give rise (as a C(6)-C(1) unit) to the p-benzoquinone rings and nuclear methyl groups (one in each case) of plastoquinone-9 and alpha-tocopherolquinone and the aromatic nuclei and nuclear methyl groups (one in each case) of gamma-tocopherol and alpha-tocopherol. 2. By using [(14)C]-homogentisic acid it has been shown that homogentisic acid is also a precursor of plastoquinone, tocopherols and alpha-tocopherolquinone in the higher plants Lactuca sativa and Rumex sanguineus, the green algae Chlorella pyrenoidosa and Euglena gracilis and the blue-green alga Anacystis nidulans.

Carbon Isotopes↗
PubMed2003

Mesonia algae gen. nov., sp. nov., a novel marine bacterium of the family Flavobacteriaceae isolated from the green alga Acrosiphonia sonderi (Kütz) Kornm.

The taxonomic position of four heterotrophic, aerobic, Gram-negative, non-motile and moderately halophilic marine bacteria, isolated from the green alga Acrosiphonia sonderi (Kütz) Kornm, was established. 16S rDNA sequence analysis indicated that the strains studied are members of the family Flavobacteriaceae, in which they form a distinct lineage. On the basis of phenotypic, chemotaxonomic, genotypic and phylogenetic data, the novel bacteria were classified as Mesonia algae gen. nov., sp. nov. The type strain is KMM 3909(T) (=KCTC 12089(T)=CCUG 47092(T)).

Chlorophyta↗
PubMed1999

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

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

Amino Acid Sequence↗
PubMed1991

Cytotoxic activity of marine algae and a cytotoxic principle of the brown alga Sargassum tortile.

Partition fractions of hexane, CCl4 and CHCl3 from methanolic extracts of marine algae were each examined for cytotoxic activities against cultured P-388 lymphocytic leukemia cells. Cytotoxic activities were found for partition fractions of 21 species of seaweed. Bioactivity-guided fractionation of the CCl4 partition fraction from Sargassum tortile, exhibiting the most prominent activity, afforded dihydroxysargaquinone (1) and sargatriol (2) previously isolated from this alga. The former was evaluated as a cytotoxic principle, and the latter, showing moderate activity, was suggested to be an artifact derived from 1 during the isolation procedure.

Animals↗
PubMed1981

[Hygienic and microbiological influences exerted on natural water biotopes by algae and the growth of water plants. 1. Communication: antibacterial properties of three water algae (Hydrodictyon reticulatum, Chlorella vulgaris, Aphanothece nidulans) in vitro (author's transl)].

The growth-inhibiting behaviour of abacterial, liquid pure cultures made up of three water algae (Hydrodictyon reticulatum, Chlorella vulgaris, Aphanothece nidulans) which were made to grow profusely in special culture containers under constant exposure to light and ventilation was examined in ten different species of microorganisms during a period of contact of 4 days both in the light and in the dark. Subjected to the test were the 5 pathogenic species Staphylococcus aureus, Klebsiella aerogenes, Pseudomonas aeruginosa, Salmonella typhimurium and Candida albicans as well the 5 bacterial contamination indicators E. coli (faecal indicator), Streptococcus faecalis (enterococci), Enterobacter aerogenes ("coliforms"), Staphylococcus epidermidis (dermic germ) and Bacillus subtilis ("contamination germ"). It was found that --Hydrodictyon reticulatum and Aphanothece nidulans exert a strong antibacterial effect, while Chlorella vulgaris provides no indication of a bacterial growth-inhibiting effect. --this antibiosis is linked with the assimilative activity of the algal cultures, as in the dark no antibacterial action is discernible --the "antibiotic principle" must be liable to transitory or rapid disintegration because the algal cultures are ineffective in the dark and also culture filtrates of 5-days old algal cultures exercise no growth-inhibiting effect. With respect to the sanitation of waters it is important to state that a profuse growth of algae produces a certain, but hardly reliable "biological water disinfection" and renders difficult the assessment of the quality of a water-course as a result of the elimination of the usual contamination indicators. Therefore, additional microbiological quality parameters must be used for assessment of pollution of swimming pools with strong algal growth.

Bacillus subtilis↗
PubMed1975

Inhibitors produced by algae as an ecological factor affecting bacteria in water. II. Antibacterial activity of algae during blooms.

It has been found that during algal blooms in an eutrophic lake occurs elimination and selection of bacteria. In this period a strong decrease in number of bacteria in the water was observed. The effect of the antibacterial substances produced by algae on the growth and respiration of bacteria isolated from the lake was investigated. The bloom forming algae were found to produce substances inhibiting the growth and respiration of Gram positive bacteria. Gram negative rods were resistant to the action of these substances. The algal substances inhibited also degradation of organic matter in the lake but only in the euphotic zone.

Anti-Bacterial Agents↗
PubMed1991

Evolution of the Rubisco operon from prokaryotes to algae: structure and analysis of the rbcS gene of the brown alga Pylaiella littoralis.

The rbcS gene coding for the small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) of the brown alga Pylaiella littoralis is located within the plastid genome and is transcribed as a single polycistronic mRNA with the gene for the large subunit of Rubisco, rbcL. The structure of the Rubisco operon from P. littoralis was determined. Molecular phylogenies for rbcS and rbcL with a wide range of prokaryotes and eukaryotes were constructed which are congruent with recent evidence for polyphyletic plastid origins. Both rbcL and rbcS of the beta-purple bacterium Alcaligenes eutrophus clearly cluster with the rhodophyte and chromophyte proteins. The data suggest that the Rubisco operons of red algal and chromophytic plastids derive from beta-purple eubacterial antecedents, rather than the cyanobacterial lineage of eubacteria from which other of their genes derive. This implies a lateral transfer of Rubisco genes from beta-purple eubacterial ancestors to the cyanobacterial ancestor of rhodophyte and chromophyte plastids.

Amino Acid Sequence↗
PubMed2003

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

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.

Agaricales↗
PubMed1997

Nutrients, Signals, and Photosynthate Release by Symbiotic Algae (The Impact of Taurine on the Dinoflagellate Alga Symbiodinium from the Sea Anemone Aiptasia pulchella).

Exogenous concentrations of 10 [mu]M to 1 mM of the nonprotein amino acid taurine stimulated photosynthate release from the dinoflagellate alga Symbiodinium, which had been freshly isolated from the sea anemone Aiptasia pulchella. Photosynthate release, as induced by taurine and animal extract, was metabolically equivalent at both concentrations in that they (a) stimulated photosynthate release to the same extent and (b) induced the selective release of photosynthetically derived organic acids. A complex mixture of amino acids at 75 mM also promoted photosynthate release, but the release rate was reduced by 34% after the omission of taurine (3 mM) from the mixture, suggesting that much of the effect of amino acids was largely attributable to taurine. Exogenous 14C-labeled taurine was taken up by the cells, and more than 95% of the internalized 14C was recovered as taurine, indicating that taurine-induced photosynthate release was not dependent on taurine metabolism. Both taurine uptake and taurine-induced photosynthate release by Symbiodinium exhibited saturation kinetics, but with significantly different Km values of 68 and 21 [mu]M, respectively. The difference in Km values is compatible with the hypothesis that Symbiodinium has a taurine signal transducer that is responsible for photosynthate release and is distinct from the taurine transporter.

Journal Article↗
PubMed2006

Temperature dependence of nitrate reductase in the psychrophilic unicellular alga Koliella antarctica and the mesophilic alga Chlorella sorokiniana.

Temperature responses of nitrate reductase (NR) were studied in the psychrophilic unicellular alga, Koliella antarctica, and in the mesophilic species, Chlorella sorokiniana. Enzymes from both species were purified to near homogeneity by Blue Sepharose (Pharmacia, Uppsala, Sweden) affinity chromatography and high-resolution anion-exchange chromatography (MonoQ; Pharmacia; Uppsala, Sweden). Both enzymes have a subunit molecular mass of 100 kDa, and K. antarctica NR has a native molecular mass of 367 kDa. NR from K. antarctica used both NADPH and NADH, whereas NR from C. sorokiniana used NADH only. Both NRs used reduced methyl viologen (MVH) or benzyl viologen (BVH). In crude extracts, maximal NADH and MVH-dependent activities of cryophilic NR were found at 15 and 35 degrees C, respectively, and retained 77 and 62% of maximal activity, respectively, at 10 degrees C. Maximal NADH and MVH-dependent activities of mesophilic NR, however, were found at 25 and 45 degrees C, respectively, with only 33 and 23% of maximal activities being retained at 10 degrees C. In presence of 2 microM flavin adenine dinucleotide (FAD), activities of cryophilic NADH:NR and mesophilic NADH:NR were stable up to 25 and 35 degrees C, respectively. Arrhenius plots constructed with cryophilic and mesophilic MVH:NR rate constants, in both presence or absence of FAD, showed break points at 15 and 25 degrees C, respectively. Essentially, similar results were obtained for purified enzymes and for activities measured in crude extracts. Factors by which the rate increases by raising temperature 10 degrees C (Q10) and apparent activation energy (E(a)) values for NADH and MVH activities measured in enzyme preparations without added FAD differed slightly from those measured with FAD. Overall thermal features of the NADH and MVH activities of the cryophilic NR, including optimal temperatures, heat inactivation (with/without added FAD) and break-point temperature in Arrhenius plots, are all shifted by about 10 degrees C towards lower temperatures than those of the mesophilic enzyme. Transfer of electrons from NADH to nitrate occurs via all three redox centres within NR molecule, whereas transfer from MVH requires Mo-pterin prosthetic group only; therefore, our results strongly suggest that structural modification(s) for cold adaptation affect thermodynamic properties of each of the functional domains within NR holoenzyme in equal measure.

Chlorella↗
PubMed1981

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

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).

Journal Article↗
PubMedDate not supplied

[Growth and development of unicellular algae in the algae-bacteria-fish biocenosis system during space flight].

The population of Chlorella cells flown as a component of the algobacterial cenosis--fish system on Cosmos-1887 was investigated. During the flight experiment over two generations of Chlorella cells were obtained. No differences in the algal growth rate in flight and on the ground were observed. On the whole, space flight did not affect the growth, development or population characteristics of Chlorella algae incorporated into the closed algobacterial cenosis-fish system.

Aerospace Medicine↗
PubMed1997

[Algae polysaccharides. 51. Study of sulfated galactan of red algae Laurencia coronopus J.Ag. (Rhodophyta, RŁhodomelaceae using partially reductive hydrolysis].

The structure of the agarlike sulfated galactan from the epiphytic red alga Laurencia coronopus was elucidated by partial reductive hydrolysis. In the presence of borane-4-methylmorpholine complex, the acid-labile glycosidic linkages of 3,6-anhydrogalactose residues of the polysaccharide are hydrolyzed with the simultaneous reduction of these residues, thus precluding their further acidic degradation. The main products of this hydrolysis were 3,6-anhydro-4-O-beta-D-galáctopyranosyl-L-dulcitol (agarobiitol), its 6-O-methyl derivative, agarobiitol 6-sulfate, and some higher oligosaccharides. These products were structurally analyzed by composition, mass spectrometry, and NMR.

Carbohydrate Sequence↗