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PubMed1983

[Growth and antimicrobial activity of an association of an actinomycete and a green alga].

During joint cultivation of the actinomycetes Streptomyces griseus (strains 65 and 744) isolated from the soil and the green algae Chlorella vulgaris larger amount of biomass as compared with solitary axenic culture have been shown. The relation of biomass of actinomycetes S. griseus strain 65 and S. griseus strain 744 and algae in the lichen-like experimentally formed thallom make up 42:1 and 40:1 relatively, i. e. the mass of actinomycetes forms 97-98% from the mass of thalloms. Actinomycetes in the associations with the algae accumulate larger amount of biomass that in the axenic cultures on corresponding medium, whereas the algae produce the same amount of the biomass as the axenic culture under the same conditions. The associations have the antimicrobic properties differed from the axenic cultures established.

Antibiosis↗
PubMed1983

Effect of temperature on chlorophyll stability of some subaerial blue-green algae.

Chlorophyll stability index of eight subaerial blue-green algal species, collected from their natural habitats, i.e., bark of trees, soil and roof-tops and from cultures, has been determined. The algae from natural habitats showed greater chlorophyll stability compared to those algae from cultures. Among the natural algae, high chlorophyll stability was observed in the algae inhabiting adverse habitats. A slight modification in the method of Murty and Majumder (1962) for determination of chlorophyll stability index has been made. Here the total percentage loss in the amount of Chl alpha of heated sample in relation to its unheated sample has been considered as chlorophyll stability index.

Chlorophyll↗
PubMed1984

[Poisoning in cattle caused by blue-green algae].

This paper describes a case of poisoning by blue-green algae growing in a fresh water pond in Goyena, Provincia de Buenos Aires. The predominating algae were identified as Microcystis aeruginosa. They show an intense growth when certain meteorologic condition prevail, in coincidence with certain chemical characteristics of the water. Once this growth has occurred, the direction of the wind has a decisive role, because it determines the accumulation on the shore, increasing their concentration and consequently, the risk of poisonous action. From a total of 170 cows, 72 died after ingestion of algae in a lapse of 24 hours. Death was very sudden so that symptoms could be observed in only 10 animals: diarrhea, incoordination, excitability, dyspnea and death. The gross lesions observed were: full stomachs showing the presence of algae; a serum-blood collection in the abdominal cavity and congestive intestines. Histopathology showed nephrosis and probable hepatic centrolobular necrosis. Water toxicity was tested on laboratory animals and gave positive results. The gross lesions, the histological changes and the laboratory tests, confirm the toxicity of the water in the pond. Toxin detection in the digestive content of the poisoned animals has not been previously mentioned in the literature; it is a very valuable diagnostic method.

Animals↗
PubMed1982

The functional analysis of the flagellar apparatus in green algae.

The flagellar apparatus of green algae is a complex organelle of great structural diversity. Diversity exists with respect to numbers of flagella, flagellar appendages (e.g., scales), origin of flagella in relation to cell symmetry, basal body and transitional region ultrastructure, fibrous structures interconnecting basal bodies and flagellar root systems. The flagellar apparatus performs several different functions in a single cell and also probably functions differently in different green algal genera. In addition to being an organelle which moves the cell through an aqueous environment the flagellar apparatus reacts to the mechanical, chemical, gravitational and light stimulation of the cell. It also plays an important role during sexual fusion of isogamous, anisogamous and oogamous species of green algae. Furthermore it contains several microtubule-organising centres (MTOCs) and in most flagellated green algae these MTOCs organise the whole microtubular system of the cell. In this review the different strategies which are currently employed to evaluate the functional significance of various structures of the flagellar apparatus in green algae are discussed. Emphasis is given to those structures which are not directly engaged in generating the motive force of flagella.

Cell Membrane↗
PubMed1975

[Food value of spiruline algae for growth of the broiler-type chicken].

Five trials were carried out during the growth (0-8 weeks) of the broiler type chicken. The weight increase was always depressed when spiruline algae replaced traditional protein sources (soybean meal, fish meal, ...) in a complete and well balanced diet (trials 1 and 2). The delay in growth was small and non significant for 5 p. 100 or less of spirulines in the diet. However, for the highest levels of spirulines the delay in growth was more pronounced, especially during the starting period (0-4 weeks): live weight gain was reduced from 16 and 26 per cent for the spirulines levels of 20 and 30 p. 100. Different methods (live weight gain, balance technique, body analysis) were used for the determination of the protein and energy efficiencies. Spirulines were fed at different levels, either added to a protein free diet (trial 3), or included with other protein sources in complete diets (trial 4). Both protein and energy efficiencies were reduced when the spiruline level increased. Thus, the protein efficiency of the spirulines was found to be similar to that of the other traditional protein sources (soybean, fish,...) for a level lower than 10 p. 100. In contrast, it was reduced (--20 p. 100) when more than 20 p. 100 of algae were included in the diet. The average metabolizable energy was 2,487 kcal per kilogram when 20 and 30 p. 100 of algae were added in the protein free diet. In the complete diets, this value was found to be smaller or greater according to the level of spirulines, 30 p. 100 reduced and 5 p. 100 increased the energy value. The poor digestibility of some glucidic fraction in the algae seems responsible for the low energy value and for the reduced growth performance. The addition of a glycolytic enzyme to the diet failed to improve the performance (trial 5).

Animal Feed↗
PubMed1998

Cellulose powder from Cladophora sp. algae.

The surface are and crystallinity was measured on a cellulose powder made from Cladophora sp. algae. The algae cellulose powder was found to have a very high surface area (63.4 m2/g, N2 gas adsorption) and build up of cellulose with a high crystallinity (approximately 100%, solid state NMR). The high surface area was confirmed by calculations from atomic force microscope imaging of microfibrils from Cladophora sp. algae.

Cellulose↗
PubMedDate not supplied

Chlorophyll-protein complexes of brown algae: P700 reaction centre and light-harvesting complexes.

Thylakoid membranes from several brown algae have been fragmented with the non-ionic detergent, Triton X-100. Three intrinsic chlorophyll-protein complexes with different pigment compositions have been isolated by sucrose density gradient centrifugation. Brown algae contain the photosystem 1 reaction-centre complex, a P700-chlorophyll a-protein which has similar spectroscopic and chemical properties to those of higher plants. This complex represents about 10--20% of the total chlorophyll in all species; the Acrocarpia paniculata complex has a chlorophyll/P700 ratio of 38. Two main light-harvesting complexes have also been isolated, which have properties unique to brown algae. The heavier of these, an orange fraction, is a fucoxanthin-chlorophyll a/c-protein; this complex contains most of the fucoxanthin and has only chlorophyll c2. The other, a green fraction, is a chlorophyll a/c-protein enriched in violaxanthin. Neither of these complexes possesses detectable photosystem 1 or photosystem 2 activities. Both of these complexes efficiently transfer light energy to chlorophyll a, indicating that the molecular arrangement of their pigments is similar to that in vivo. Differential extraction of thylakoid membranes indicates that the P700-chlorophyll a-protein is the complex most firmly embedded in the membrane, but the fucoxanthin-chlorophyll a/c-protein is the least firmly bound. We suggest that the fucoxanthin complex is the most variable component of the photosynthetic unit of brown algal chloroplasts.

Cell Membrane↗
PubMed2007

Limits to productivity of the alga Pleurochrysis carterae (Haptophyta) grown in outdoor raceway ponds.

This study examined the effects of oxygen concentration, pond temperature and irradiance on productivity and CaCO(3) formation of the coccolith-forming alga, Pleurochrysis carterae CCMP647 grown in semi-continuous culture in outdoor raceway ponds. During the day the oxygen content of the pond increases markedly and P. carterae photosynthesis is inhibited by these high O(2) concentrations with the inhibition increasing with increasing temperature. The high irradiance outdoors presents less of a problem to photosynthesis and productivity as the algae can acclimate well to high irradiances over a period of several weeks. Pond depth also effects productivity and this effect varies with season. During autumn, productivities were highest at depths of 13 to 16 cm, and decreased when the depth was increased. During summer productivity was much lower at 13 cm pond depth and increased when the depth was increased to 16, 18 and 21 cm. Heating the ponds in the morning by approximately 3 to 5 degrees C improves productivity by 11%-21%, presumably because this allows the algae to photosynthesise faster in the conditions of low [O(2)] which occur in the early morning.

Acclimatization↗
PubMed1975

Sensitization of algal virus to UV by the incorporation of 5-bromouracil and mutations of host alga Plectonema boryanum.

Ultraviolet light (UV) sensitivity and photoreactivation of algal virus (cyanophage) LPP-1 were studied after multiplication in host alga Plectonema boryanum in presence of 5-bromouracil (5-BU) alone and in conjunction with sulfanilamide. Virus particles containing 5-BU were more sensitive towards UV and also showed low photoreactivation. There was less incorporation of 5-BU in virus without pretreatment of host alga with sulfanilamide, an inhibitor of thymine synthesis. 5-BU-induced short trichome mutants of Plectonema boryanum were isolated. These mutants grew slowly in liquid medium as well as on agar plates and differed in other morphological characters. Reversion of short trichome mutants was observed with a frequency of about 10(-3), but revertants were different from parent alga. The short trichome mutants were sensitive to virus LPP-1 and resistant towards UV.

Bromouracil↗
PubMed1976

Growth and nitrogen fixation of mutants defective in heterocyst differentiation in the blue-green alga Cylindrospermum sp.

Three classes of spontaneous and N-methyl-N'-nitro-N-nitrosoguanidine (NTG)-induced mutants of the blue-green alga Cylindrospermum sp. were isolated in the presence of combined nitrogen. Mutants with complete loss of heterocyst differentiation formed longer filaments than the parent alga and were unable to grow in nitrogen-free medium and to fix nitrogen. The second type of mutants formed long filaments with terminal heterocysts. In the third type of mutants, paired proheterocyst differentiation occurred at regular intervals in long filaments and these were defective in their further development into mature heterocysts. Mutants with decreased heterocyst frequency due to defective differentiation and development showed less growth and nitrogen fixation in nitrogen-free medium than the parent alga.

Chloramphenicol↗
PubMed2004

Toxicity testing of heavy-metal-polluted soils with algae Selenastrum capricornutum: a soil suspension assay.

A small-scale Selenastrum capricornutum (Rhapidocelis subcapitata) growth inhibition assay was applied to the toxicity testing of suspensions of heavy-metal-polluted soils. The OECD 201 standard test procedure was followed, and algal biomass was measured by the fluorescence of extracted chlorophyll. The soils, which contained up to (per kilogram) 1390 mg of Zn, 20 mg of Cd, and 1050 mg of Pb were sampled around lead and zinc smelters in northern France. The water extractability of the metals in suspensions (1 part soil/99 parts water w/v) was not proportional to the pollution level, as extractability was lower for soil samples that were more polluted. Thus, the same amount of metals could be leached out of soils of different levels of pollution, showing that total concentrations of heavy metals in soil (currently used for risk assessment purposes) are poor predictors of the real environmental risk via the soil-water path. Despite high concentrations of water-extracted zinc (0.6-1.4 mg/L of Zn in the test), exceeding by approximately 10-fold the EC(50) value for S. capricornutum (0.1 mg Zn/L), 72-h algal growth in the soil extracts was comparable or better than growth in the standard control OECD mineral medium. The soil suspension stimulated the growth of algae up to eightfold greater than growth using the OECD control medium. Growth stimulation of algae was observed even when soil suspensions contained up to 12.5 mg Zn/L and could not be explained by supplementary nitrogen, phosphorous, and carbonate leached from the soil. However, if the growth of algae in suspensions of clean and polluted soils was compared, a dose-dependent inhibitory effect of metals on algal growth was demonstrated. Thus, as soil contains nutrients/supplements that mask the adverse effect of heavy metals, a clean soil that has properties similar to the polluted soils should be used instead of mineral salt solution as a control for analysis of the ecotoxicity of soils.

Cadmium↗
PubMed1998

An atypical cytochrome b in the colorless alga Polytomella spp.: the high potential bH heme exhibits a double transition in the alpha-peak of its absorption spectrum.

Polytomella spp. is a colorless alga of the family Chlamydomonadaceae that lacks chloroplasts and cell wall. A highly active ubiquinol-cytochrome c oxidoreductase (bc1 complex), sensitive to antimycin and myxothiazol, has been purified and characterized from this alga (Gutiérrez-Cirlos et al., 1994, J. Biol. Chem. 269, 9147-9154). Both in mitochondrial membranes and in the isolated complex, the visible spectrum of cytochrome b from Polytomella spp. exhibits an atypical alpha-band with a maximum at 567 nm. This maximum is shifted 3-4 nm to the red when compared with b-type cytochromes from other organisms. Analysis of the b hemes of the bc1 complex by high performance liquid chromatography revealed no differences in the retention time and in the absorption spectra of the b-type hemes from Polytomella spp. and hemin, indicating that the prosthetic group in this alga is protoheme and thus ruling out the possibility that the red-shift could be due to different chemical substitutions in the porphyrin rings of the bL or bH hemes. The two b hemes were characterized by electrochemical redox titration; at pH 7.8-8.0, the midpoint potential for bL was-143 mV and for bH +25 mV. The spectra of the two b-type hemes were recorded in the presence of different reductants, at selected electrochemical potentials, and in the presence of antimycin A, to distinguish between the contribution of bL and bH to the visible spectrum. Both hemes bL and bH of the algal cytochrome b contribute to the observed bathochromic absorption maximum in the alpha-band of the spectrum. The data also show that the low potential bL heme from Polytomella spp. is spectroscopically similar to that of other organisms, with two transitions in the alpha-peak at 558.7 and 568.4 nm. The high-potential heme bH also exhibits a spectrum with two transitions at 557.2 and 568.9 nm, which surprisingly differs from the spectra of cytochrome bH of mammals, plants, yeasts, and bacteria, which all exhibit a single transition centered around 560 nm.

Animals↗
PubMedDate not supplied

Assessment of the ecotoxic potential of soil contaminants by using a soil-algae test.

To assess the ecotoxic potential of soil contaminants, a test with the soil alga Chlorococcum infusionum has been developed, enabling investigations of soil pollutions with soluble and fairly soluble chemicals. Three soil types artificially contaminated with Sb compounds and five soils from a historical mining area, which were highly polluted with Sb, As, Hg, and Cu, were used as test soils. For antimony, EC50 values from 125 mg/kg up to > 1000 mg/kg, depending on soil type, were determined. Two of five soils from the mining area caused toxic effects. Additionally, aqueous extracts of all soils were exposed in established tests (daphnid, alga, bacterium). In contrast with the soil-algae test, no toxic effects were found. Aquatic tests with SbO/K tartrate were performed to point out the toxicity of antimony. The following EC50 values in milligrams of Sb per liter were determined: Scenedesmus subspicatus, 59 mg/liter; Chlorococcum infusionum, 43 mg/liter; Daphnia magna, 8 mg/liter; and Vibrio fisheri, 7 mg/liter.

Animals↗
PubMed1998

Comparison of tributyltin compound effects on the alga Scenedesmus quadricauda and the benthic organisms Tubifex tubifex and Chironomus plumosus.

The inhibitory and toxic effects of five tributyltin compounds and one dibutyltin compound were determined under standardized conditions on the freshwater plankton alga Scenedesmus quadricauda and the benthic organisms Tubifex tubifex and Chironomus plumosus. Observed were the mortality of benthos after 96 h and the inhibition of growth, photosynthesis, and chlorophyll a content of the alga after 12 days of cultivation. The effects of the compounds were expressed as LC50 values for mortality and EC50 values for inhibition. Attention was focused on the influence of the bound X anion on the toxicological effects of the test compounds [dibutyltin bis(N,N-diethyldithiocarbamate (DBTC); bis(tributyltin 3,4,5, 6-tetrachlorophthalate (TBTP); tributyltin sulfaminate (TBTS); tributyltin N,N-diethyldithiocarbamate (TBTC); tributyltin naphthenate (TBTN); bis(tributyltin) oxide) (TBTO)]. From the results obtained the following conclusions can be made: For benthic organisms the anionic group N,N-diethyldithiocarbamate as well as the anionic inorganic group oxide had a very large toxic effect. The lowest efficiency was indicated for the 3,4,5,6-tetrachlorophthalate anion. When the positions of the tested compounds with respect to dependence of the bound anion were evaluated for the alga, it was concluded that the position of the anionic group in inhibitory rank orders depended on the parameter. The efficiency of the organic anion N,N-diethyldithiocarbamate was low in all divisions tested (especially for photosynthesis inhibition). Strong effects for all parameters tested were noted for the compound with organic anion 3,4, 5,6-tetrachlorophthalate as well as the compound with the inorganic anion oxide, except for photosynthesis inhibition. From the results obtained the following rank orders of toxicity and/or inhibition are established: T. tubifex-TBTO>TBTC>TBTN>DBTC>TBTS>TBTP; Ch. plumosus-TBTS>/=TBTC>TBTO>TBTN>DBTC>TBT P; S. quadricauda, growth inhibition--TBTO>TBTP>TBTN>TBTC>DBTC=TBTS; S. quadricauda, chlorophyll a content-TBTO>/=DBTC>TBTP=TBTC>TBTN=TBTS; S. quadricauda, photosynthesis inhibition--TBTP>TBTS>/=TBTN>DBTC>TBTO>TBTC.

Animals↗
PubMed1979

Polyploidy in algae.

The green algae and the charophytes represent the most widely studied groups of algae in respect to their ploidy levels. In some genera increased size accompanies ploidy level changes as well as certain morphological modifications, but in other genera no evident obvious changes can be discerned. In the other major groups of algae, namely the Rhodophycophyta and Phaeophycophyta, few cases of polyploidy have been documented adequately. In the remaining groups, unusual nuclear phenomena and/or behavior have hampered studies and few species have adequately been studied in regard to their polidy levels.

Eukaryota↗
PubMed1993

Organization of plastid-encoded ATPase genes and flanking regions including homologues of infB and tsf in the thermophilic red alga Galdieria sulphuraria.

We have cloned and sequenced the plastid ATPase operons (atp1 and atp2) and flanking regions from the unicellular red alga Galdieria sulphuraria (Cyanidium caldarium). Six genes (5 atpI, H, G, F, D and A 3) are linked in atp1 encoding ATPase subunits a, c, b, b, delta and alpha, respectively. The atpF gene does not contain an intron and overlaps atpD by 1 bp. As in the genome of chloroplasts from land plants, the cluster is located downstream of rps2, but between this gene and atp1 we found the gene for the prokaryotic translation elongation factor TS. Downstream of atpA, we detected two open reading frames, one encoding a putative transport protein. The genes atpB and atpE, encoding ATPase subunits beta and epsilon, respectively, are linked in atp2, separated by a 2 bp spacer. Upstream of atpB, an uninterrupted orf167 was detected which is homologous to an intron-containing open reading frame in land plant chloroplasts. This orf167 is preceded on the opposite DNA strand by a homologue to initiation factor 2 in prokaryotes. The arrangement of atp1 and atp2 is the same as observed in the multicellular red alga Antithamnion sp., indicating a conserved genome arrangement in the red algal plastid genome. Differences compared to green chloroplast genomes suggest a large phylogenetic distance between red algae and green plants, while similarities in arrangement and sequence to chromophytic ATPase operons support a red algal origin of chlorophyll a/c-containing plastids or alternatively point to a common prokaryotic endosymbiont.

Adenosine Triphosphatases↗
PubMed1994

The evolutionary origin of red algae as deduced from the nuclear genes encoding cytosolic and chloroplast glyceraldehyde-3-phosphate dehydrogenases from Chondrus crispus.

Algae are a heterogeneous group of photosynthetic eukaryotes traditionally separated into three major subdivisions: rhodophytes, chlorophytes, and chromophytes. The evolutionary origin of rhodophytes or red algae and their links to other photosynthetic and nonphotosynthetic eukaryotes have been a matter of much controversy and speculation. Here we present the first cDNAs of nuclear protein genes from red algae: Those encoding cytosolic and chloroplast glyceraldehyde-3-phosphate dehydrogenases (GAPDH) from Chondrus crispus. A phylogenetic analysis including GAPDH gene sequences from a number of eukaryotic taxa, cyanobacteria, and purple bacteria suggests that chloroplasts and rhodoplasts together form a monophyletic group of cyanobacterial descent and that rhodophytes separated from chlorophytes at about the same time as animals and fungi. The composite GAPDH tree further demonstrates that chloroplast and cytosolic GAPDH genes are closely related to their homologs in cyanobacteria and purple bacteria, respectively, the presumptive ancestors of chloroplasts and mitochondria, thereby firmly establishing the endosymbiotic origin of these nuclear genes and their fixation in eukaryotic cells before the rhodophyte/chlorophyte separation. The present data are in conflict with phylogenetic inferences based on plastid-encoded rbcL sequences supporting a polyphyletic origin of rhodoplasts and chloroplasts. Comparison of rbcL to GAPDH phylogenies suggests that rbcL trees may be misleading because they are composed of branches representing ancient duplicated (paralogous) genes.

Amino Acid Sequence↗
PubMed1996

Effects of organic solvents and solvent-atrazine interactions on two algae, Chlorella vulgaris and Selenastrum capricornutum.

When assessing pesticides toxicity on test organisms, the use of organic solvents is frequently required to formulate solutions of pesticides having low or moderate water solubility. These solvents may influence the results of toxicity tests. This study examined the effects of ethanol and dimethyl sulfoxide (DMSO) on two species of algae, Chlorella vulgaris and Selenastrum capricornutum. The interactives effects of these organic solvents with various concentrations of atrazine were tested to analyse how these solvents can affect the toxicity of atrazine. Toxicity was measured as the change in chlorophyll (a) content (estimated via fluorescence) in cultures of the test organism that were incubated over a 96-h period at standard conditions of temperature and light. In the absence of atrazine, ethanol was toxic to both algae, yielding significant inhibition of chlorophyll (a) content at concentrations as low as 0.05%. Morever, S. capricornutum was less sensitive to ethanol than was C. vulgaris. DMSO did not show any toxic effects on either chlorophycea. At concentrations up to 0.5%, DMSO interacted additively with atrazine for both chlorophycea. An additive response was also observed with ethanol towards S. capricornutum. For C. vulgaris, ethanol interacted antagonistically at most of atrazine concentrations and gave few additive and synergistic interactions. An additive response of an atrazine-solvent mixture indicate the inherent toxicity of the atrazine. Since DMSO generally gave additive responses for both algae, it can be considered as an adequate organic solvent to use in bioassays.

Atrazine↗