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At least 19 recordsLinked to original sources
PubMed1978

Anilines: selective toxicity to blue-green algae.

The blue-green alga Agmenellum quadruplicatum (strain PR6) was very sensitive to aniline and p-toluidine (potential environmental toxicants) in an algal lawn assay (the growth of the algal lawn was inhibited with as little as 1 microgram of p-toluidine per disk). Assays with seven other species of blue-green algae showed that they had varying sensitivities ranging from 1 to 100 micrograms of p-toluidine. Under comparable conditions, 0.5 milligram or more of p-toluidine was needed to inhibit a green alga, a diatom, or two species of bacteria. p-Toluidine had no immediate effect on the photosynthesis or respiration of A. quadruplicatum, although growth was arrested and viability declined.

Aniline Compounds↗
PubMed1990

Higher plant origins and the phylogeny of green algae.

5S rRNA sequences from six additional green algae lend strong molecular support for the major outlines of higher plant and green algae phylogeny that have been proposed under varying naming conventions by several authors. In particular, the molecular evidence now available unequivocally supports the existence of at least two well-separated divisions of the Chlorobionta: the Chlorophyta and the Streptophyta (i.e., charophytes) (according to the nomenclature of Bremer). The chlamydomonad 5S rRNAs are, however, sufficiently distinct from both clusters that it may ultimately prove preferable to establish a third taxon for them. In support of these conclusions 5S rRNA sequence data now exist for members of four diverse classes of chlorophytes. These sequences all exhibit considerably more phylogenetic affinity to one another than any of them show toward members of the other cluster, the Streptophyta, or the two Chlamydomonas strains. Among the Charophyceae, new 5S rRNA sequences are provided herein for three genera, Spirogyra, Klebsormidium, and Coleochaete. All of these sequences and the previously published Nitella sequence show greater resemblance among themselves and to the higher plants than they do to any of the other green algae examined to date. These results demonstrate that an appropriately named taxon that includes these green algae and the higher plants is strongly justified. The 5S rRNA data lack the resolution needed, however, to unequivocally determine which of several subdivisions of the charophytes is the sister group of the land plants. The evolutionary diversity of Chlamydomonas relative to the other green algae was recognized in earlier 5S rRNA studies but was unanticipated by ultrastructural work.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗
PubMed1989

Some properties and amino acid sequence of plastocyanin from a green alga, Ulva arasakii.

Plastocyanin was purified from a multicellular, marine green alga, Ulva arasakii, by conventional methods to homogeneity. The oxidized plastocyanin showed absorption maxima at 252, 276.8, 460, 595.3, and 775 nm, and shoulders at 259, 265, 269, and 282.5 nm; the ratio A276.8/A595.3 was 1.5. The midpoint redox potential was determined to be 0.356 V at pH 7.0 with a ferri- and ferrocyanide system. The molecular weight was estimated to be 10,200 and 11,000 by SDS-PAGE and by gel filtration, respectively. U. arasakii also has a small amount of cytochrome c6, like Enteromorpha prolifera. The amino acid sequence of U. arasakii plastocyanin was determined by Edman degradation and by carboxypeptidase digestion of the plastocyanin, six tryptic peptides, and five staphylococcal protease peptides. The plastocyanin contained 98 amino acid residues, giving a molecular weight of 10,236 including one copper atom. The complete sequence is as follows: AQIVKLGGDDGALAFVPSKISVAAGEAIEFVNNAGFPHNIVFDEDAVPAGVDADAISYDDYLNSKGETV VRKLSTPGVY G VYCEPHAGAGMKMTITVQ. The sequence of U. arasakii plastocyanin is closet to that of the E. prolifera protein (85% homology). A phylogenetic tree of five algal and two higher plant plastocyanins was constructed by comparing the amino acid differences. The branching order is considered to be as follows: a blue-green alga, unicellular green algae, multicellular green algae, and higher plants.

Amino Acid Sequence↗
PubMed1978

Isolation and properties of fungi that lyse blue-green algae.

Of 70 pure microbial cultures isolated from aquatic habitats, soil, and air according to the ability to lyse live blue-green algae, 62 were fungi representing the genera Acremonium, Emericellopsis, and Verticillium. Algal-lysing fungi were isolated from all habitat types sampled. The remaining isolates comprised four bacteria and four streptomycetes. All isolates lysed Anabaena flos-aquae and, in most cases, several other filamentous and unicellular blue-green algae. The fungi generally showed greater activity than most other isolates towards a wider range of susceptible algae, including green algae in some cases. Acremonium and Emericellopsis isolates, but not Verticillium, also inhibited the growth of blue-green algae and gram-positive bacteria, but did not lyse the latter. Lysis of blue green algae by Acremonium and Emericellopsis spp. was associated with the formation of diffusible heat-stable extracellular factors which, evidence suggests, could be cephalosporin antibiotic(s). Blue-green algae were also lysed by pure cephalosporin C. The frequent isolation of lytic fungi from algal habitats suggests a possible natural algal-destroying role for such fungi, which might be exploitable for algal bloom control.

Air Microbiology↗
PubMed1992

The syntheses of plastocyanin and cytochrome c-553 are regulated by copper at the pre-translational level in a green alga, Pediastrum boryanum.

The green alga Pediastrum boryanum synthesizes alternatively two photosynthetic electron carrier proteins, plastocyanin and cytochrome c-553, depending on the copper concentration of the medium. We studied the levels at which the syntheses of the two proteins are regulated. Plastocyanin and cytochrome c-553 were purified from P. boryanum NIES-301 cells, having apparent molecular weights of 14,600 and about 12,000, respectively. Western blotting with antisera raised against these proteins showed accumulation of (apo)plastocyanin and (apo)cytochrome c-553 in the cells grown with (2 microM) and without added CuSO4, respectively, but no accumulation of the precursor proteins in both cultures. The translatable mRNAs for the two proteins were examined by in vitro translation with total RNA and wheat germ extract followed by immunoprecipitation and SDS-PAGE. The 21-kDa polypeptide (preapoplastocyanin) was detected with anti-plastocyanin serum in copper-sufficient cells; the 23-kDa polypeptide (preapocytochrome c-553) with anti-cytochrome c-553 serum in copper-deficient cells. The translatable mRNA for preapoplastocyanin appeared in 1 h and (apo)plastocyanin in 2-3 h after the addition of 2 microM CuSO4 to the copper-deficient culture. The translatable mRNA for preapocytochrome c-553 disappeared within 4-5 h, while (apo)cytochrome c-553 disappeared more slowly. It is concluded that the syntheses of plastocyanin and cytochrome c-553 are regulated by copper at the pre-translational (i.e., transcriptional or post-transcriptional) level in P. boryanum NIES-301.

Blotting, Western↗
PubMedDate not supplied

[Activity of aminotransferases in the blue green alga Anacystis nidulans].

The blue-green alga Anacystis nidulans (strain L 1402-1) was grown at +37 degrees C in air (0.03 vol% CO2 and in air enriched with 3.0 vol% CO2. The effects of several inhibitors on the activity of aminotransferases, 14CO2 fixation and radioactive photosynthetic products of Anacystis were studied. No serine-pyruvate aminotransferase activity could be found in 10-2 M isonicotinyl hydrazide (INH); under the influence of this inhibitor aspartate and alanine aminotransferase were decreased about 49% respectively 17.6%. Serine-pyruvate and alanine aminotransferase activity decreased to more than 50% in 10-3 M glyoxalbisulfite. The obtained inhibitory effect of 10-4 M HPMS on serine-pyruvate aminotransferase (35%) was stronger than one the other aminotransferases. DCMU (5 x 10-6 M) inhibition on alanine aminotransferase activity was 83.7%. Under the influence of 10-3 M glyoxalbisulfite no 14C-labelled amino acids could be detected after 5 min photosynthesis; 14C-labelling of phosphoenolpyruvate, malate, phosphoglycolate and glycolic acid increased. Isonicotinyl hydrazide (10-2 M) caused in comparison to the control experiment a lower radioactivity in aspartate glutamate and phosphoenolpyruvate. The results are discussed with reference fo the operation of the glycolate pathway and a carboxylation reaction of phosphoenol-pyruvate in the blue-green alga Anacystis nidulans.

Alanine Transaminase↗
PubMed1978

Extracellular release of organic products and growth of bacteria in Anabaena cylindrica (blue-green alga) culture.

The studies were made with stationary cultures of Anabaena cylindrica (blue-green alga). The bacterial microflora accompanying blue-green algae is subject to succession and elimination in the course of growth. The bacteria are able to utilize organic products released by the blue-green algae. The products released by A. cylindrica to the environment are peptide-like compounds.

Chlorophyll↗
PubMed1976

Halophilic-blue-green algae.

The isolation of a halophilic blue-green alga, Aphanothece halophytica, from Great Salt Lake is described. The organism was cultured from waters with salinities up to saturated NaC1 (about 30% w/v). It has an optimum salinity for growth of about 16% NaC1, but can grow very slowly even in saturated NaC1. Based on the study of the Great Salt Lake organism, and on a review of the earlier literature, it is concluded that despite recent reports to the contrary, true halophilic blue-green algae do exist.

Cyanobacteria↗
PubMed1976

Chlorophyll and peptide compositions in the two photosystems of marine green algae.

The molar ratios of chlorophyll a to b in the thalli of marine green algae were between 1.5 and 2.2, being appreciably lower than the ratio between 2.8 and 3.4 found for the leaves of higher plants and the cells of fresh-water green algae. The ratio of chlorophylls to P-700 in these marine algae was also lower than that in higher plants. The a/b ratios in the pigment proteins of Photosystems 1 and 2 separated by polyacrylamide-gel electrophoresis from sodium dodecyl sulfate-solubilized chloroplasts of four species of marine green algae, Bryopsis maxima, Cheatomorpha spiralis, Enteromorpha compressa and Ulva conglobata, were approximately 5 and 1, which are considerably smaller than the ratios, 7 and 2, respectively, found for the pigment proteins of the two photosystems of higher plants separated by the same technique. The chloroplasts of Bryopsis maxima and Cheatomorpha spiralis lacked two of the peptides associated with Photosystem II, which are present in the chloroplasts of Spinacia oleracea and Taraxacum officinale.

Binding Sites↗
PubMed1990

Chemical composition, in vitro protein digestibility and in vitro available iron of blue green alga, Nostoc commune.

Blue-green alga, Nostoc commune, contained moderate amounts of protein and iron. Its in vitro protein digestibility was 43.50%. The soluble and ionic iron from the alga was extractable to some extent at pH 1.5 but was not detectable at pH 8.0. The digestion by protease did not affect the iron detection. Heat processing at 100 and 120 degrees C failed to increase the digestibility and the content of available iron. The dietary fiber in the alga may be responsible for low protein digestion and low iron availability.

Biological Availability↗
PubMed2025

Genome editing in the green alga Chlamydomonas: past, present practice and future prospects.

The green alga Chlamydomonas is an important and versatile model organism for research topics ranging from photosynthesis and metabolism, cilia, and basal bodies to cellular communication and the cellular cycle and is of significant interest for green bioengineering processes. The genome in this unicellular green alga is contained in 17 haploid chromosomes and codes for 16 883 protein coding genes. Functional genomics, as well as biotechnological applications, rely on the ability to remove, add, and change these genes in a controlled and efficient manner. In this review, the history of gene editing in Chlamydomonas is put in the context of the wider developments in genetics to demonstrate how many of the key developments to engineer these algae follow the global trends and the availability of technology. Building on this background, an overview of the state of the art in Chlamydomonas engineering is given, focusing primarily on the practical aspects while giving examples of recent applications. Commonly encountered Chlamydomonas-specific challenges, recent developments, and community resources are presented, and finally, a comprehensive discussion on the emergence and evolution of CRISPR/Cas-based precision gene editing is given. An outline of possible future paths for gene editing based on current global trends in genetic engineering and tools for gene editing is presented.

Gene Editing↗
PubMed1992

Group I introns within the nuclear-encoded small-subunit rRNA gene of three green algae.

Four group I introns from the nuclear-encoded (18S) rRNA genes of three chlorophycean green algae are described; two are in Dunaliella parva, and one each is in D. salina and Characium saccatum. The introns within the gene in the latter two organisms are located at the sites equivalent to the 5' and 3' introns of D. parva, respectively. All four introns lack open reading frames and are relatively small, 381-447 bp. Both primary- and secondary-structural features place these introns within subgroup IC1 described by Michel and Westhof. Phylogenetic relationships of the three intron-containing taxa and their relatives, as inferred from comparisons of 18S rDNA sequences, suggest that inheritance of the introns along with the gene can account for their present distribution. The discovery of these four introns, in addition to two others known to exist in other chlorophycean green algae, suggests that group I introns within the 18S rRNA gene may be relatively common in the green algae.

Base Sequence↗
PubMed1976

Ribonucleotide reductase in blue-green algae: dependence on adenosylcobalamin.

Ten species of freshwater blue-green algae exhibit an adenosylcobalamin-dependent ribonucleotide reductase, thuse explaining the requirement for cobalt by these organisms. The evidence suggests a phylogenetic affinity between the cyanophytes and bacteria, such as Clostridium and Rhizobium, and the euglenoid flagellates, which also use the cofactor-dependent reductase. In contrast, the ribonucleotide reductase reaction in the few green algae surveyed shows no dependence on cobalamins.

Biological Evolution↗
PubMed1978

The blue-green algae in nuclear power plant cooling water.

A study was undertaken to determine the effects of passage through the cooling system of the Zion Nuclear Plant, Illinois, U.S.A., on the blue-green algae present in lake water. The blue-green algae were isolated by means of membrane filtration, enumerated and identified to genera. As a result of cooling system passage there was a definite reduction in the numbers of blue-green algae. This reduction appeared to be due to mechanical, as well as elevated temperature, damage. A few genera showed only a slight change in number.

Cyanobacteria↗
PubMedDate not supplied

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

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

Carotenoids↗
PubMed1978

Hydrogen metabolism in blue-green algae.

This manuscript reviews the literature on hydrogen metabolism in blue-green algae and reports some new data from this laboratory. H2-formation by intact cells is found to be catalyzed exclusively by nitrogenase. Its rate appears to be variable from strain to strain used byt is--in our hands--very small. Therefore, blue-green algae are presumably of limited value in projects of solar energy conversion to form molecular hydrogen. These organisms are also able to consume the gas in a reaction catalysed by hydrogenase. Hydrogen is mainly consumed in an oxygen dependent reaction, as in aerobic nitrogen fixing bacteria. It can also serve as an electron donor for nitrogen fixation under certain physiological conditions. In experiments with a cell-free preparation, hydrogenase is found to be membrane-bound. The enzyme is characterized with respect to its specifity towards electron donors and acceptors.

Aerobiosis↗
PubMedDate not supplied

[Structure and cell division of the blue-green alga Plectonema boryanum].

Our data on the structure of the blue-green alga Plectonema boryanum, as well as the analysis of the data of other authors, show that its cells resemble bacterial cells in the basic features of their fine structure (the cell wall, cytoplasmic membrane, nucleoid, membraneous formations, ribosomal apparatus). Besides the organelles typical of blue-green algae, organelles similar to mesosomes and formations looking like lysosomes were found in Pl. boryanum. Data obtained in the course of the formation of cell partitions evidently speak in favour of the many-sided activity of the lamellae of the photosynthetic apparatus (the parachromatophore) of Pl. boryanum.

Cell Membrane↗