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At least 1,063 records · Page 59Linked to original sources
PubMed1975

[Physico-chemical determination of the ploidy of the unicellular alga, Chlorella pyrenoidosa (strain 211/8b) (author's transl)].

The ploidy of the unicellular green alga Chlorella pyrenoidosa (strain 211/8b) has been determined by means of renaturation kinetics. The nuclear DNA is made up from fast, intermediate and slow renaturing sequences, which represent respectively about 5, 15 and 80% of the DNA. These observations are consistent with the findings in other eukaryotic nuclear DNAs. Nevertheless, the relative importance of the repeated sequences is much lower than that observed in Chlamydomonas reinhardi [16] and in higher plants [18-20], but slightly higher than that obtained in Chlorella vulgaris [17]. The kinetic complexity of the main fraction of the Cl. pyrenoidosa nuclear DNA is found to be 2.94 - 10-10 daltons (mean value of five independant experiments) assuming value of 2.1 - 10-8 daltons for Cl. pyrenoidosa chloroplastic DNA. When compared with the analytical complexity of this fraction (80% of the nuclear DNA analytical complexity, that is 2.02 - 10-10 daltons), one can assume that the slow renaturing fraction of the nuclear DNA is constituted by a unique nucleotide sequence. This result thus suggests that Cl. pyrenoidosa (strain 211/8b) is an haploid organism. The possible existence of an haploid genome in the nuclei of the algae from Chlorella genus and the apparent absence of sexuality might explain the high discrepancy observed in the G + C content of the Chlorella nuclear DNAs.

Chlorella↗
PubMedDate not supplied

[Lipids from the green algae Botryococcus during staged growth in batch mode].

The lipid fraction of the green alga Botryococcus cultured in a batch mode was found to contain polar lipids (more than 50% of the total lipids), di- and triacylglycerides, steroids and their esters, free fatty acids, and hydrocarbons. In senescent culture, the content of polar lipids somewhat decreased and that of triacylglycerides increased by more than four times. The content of hydrocarbons in the algal biomass did not exceed 0.9% and depended little on the culture age. Intracellular lipids contained saturated and unsaturated (mono-, di-, and trienoic) fatty acids. The maximum content of C16:3 and alpha-C18:3 fatty acids (up to 35% of the total fatty acids) was detected in the phase of active growth. The extracellular and intracellular lipids of the alga differed in the proportion of particular lipids and in the fatty acid pattern.

Chlorophyta↗
PubMedDate not supplied

Comparison of liquid chromatography/mass spectrometry, ELISA, and phosphatase assay for the determination of microcystins in blue-green algae products.

More than 100 samples of blue-green algae products (consisting of Aphanizomenon, Spirulina, and unidentified blue-green algae) in the form of pills, capsules, and powders were collected from retail outlets from across Canada. The samples were extracted with 75% methanol in water and centrifuged to remove solids. Aliquots of the extracts along with spiked blank sample extracts were sent to each participating laboratory and independently analyzed for microcystins by enzyme-linked immunosorbent assay (ELISA), protein phosphatase inhibition assay, and by liquid chromatography-tandem mass spectrometry (LC-MS/MS) after sample cleanup using C18 solid-phase extraction. The results obtained by ELISA and LC-MS/MS agreed very well over a concentration range of about 0.5-35 microg/g. The colorimetric phosphatase results generally agreed with the other 2 methods. While the 2 biochemical assays measured total microcystin content compared with a standard of microcystin LR, the LC-MS/MS method measured specific microcystins (LA, LR, RR, YR) using external standards of these for identification and quantitation. Microcystin LR was found in all positive samples by LC-MS/MS. Microcystin LA was the only other microcystin found in the samples analyzed. These 2 microcystins represent essentially all the microcystins that were present in the extracts. Otherwise, the LC-MS/MS results would have been significantly lower than the results of the biochemical assays had other unknown microcystins been present.

Chromatography, Liquid↗
PubMed1997

The position of nuclei and the role of cytoskeleton in graviresponse of siphonaceous algae Vaucheria sessilis.

Gravity has always been present during evolution. Through the process of natural selection, contemporary organisms could show evidence of having turned gravity to their advantage as an adjunct to development. In recent time great success has been achieved in description and analysis of gravitaxis mechanism of algae Chara (Sievers et. al., 1991) and Euglena (Hader et. al., l990). The aim of present investigation was the demonstration of gravity-dependent growth and development of algae without distinct gravitaxis and gravitisensor organelles, such as statoliths and amyloplasts.

Cell Nucleus↗
PubMedDate not supplied

Supercritical fluid extraction of halogenated monoterpenes from the red alga Plocamium cartilagineum.

Supercritical fluid extraction (SFE) of the marine red alga Plocamium cartilagineum, which is known to contain complex mixtures of halogenated monoterpenes, was investigated. P. cartilagineum samples were extracted by SFE with carbon dioxide and modified carbon dioxide containing up to 10% methanol at different pressure and temperature conditions to establish the optimum conditions for extraction. These conditions were then used in the extraction of halogenated monoterpenes from 2 different samples of P. cartilagineum: one from Davenport, CA, and the other from Casa Beach (San Diego, CA). Several halogenated monoterpenes isolated by conventional solvent extraction with methanol and purified by column chromatography were used as the reference compounds for the determination of the extraction efficiency in the SFE experients. Plocamium cartilagineum belongs to the red alga family--Plocamiaceae, and has been found to contain a large number of halogenated monoterpenes, whose structures typically contain 1-6 bromine and/or chlorine atoms. P. cartilagineum grows along the Pacific coast from Washington to Chile, the British Isles, Australia, and Spain. Interestingly, P. cartilagineum collected from different geographical areas in the world are all reported to produce halogenated monoterpenes, but of different structural types and halogen substitution patterns. Most of these halogenated monoterpenes have been found to exhibit varied biological activities, including antifungal, antimicrobial, and molluscicidal activity.

Carbon Dioxide↗
PubMed2001

Sources of the eutrophication problems associated with toxic algae: an overview.

Blooms of cyanobacteria (toxic blue-green algae) can produce health and environmental hazards in water, including water used for drinking or recreational purposes. How, why, and when these blooms are produced, as well as how to deal with them, are questions whose answers are vital to the safeguarding of public health in regions where the algae occur. The blooms are linked to eutrophication of water, and this paper discusses the eutrophication problems, their nature, and their relevance to the production of cyanobacteria. Nutrient limitations on algal productivity are considered, as is the involvement of the atmosphere, the storage of nutrients in soils, and the influence of anthropogenic activity.

Agriculture↗
PubMedDate not supplied

Effect of diesel fuel pollution on the lipid composition of some wide-spread Black Sea algae and invertebrates.

Two green algae (Ulva rigida and Cladophora coelothrix), the mussel Mytilus galloprovincialis and the snail Rapana thomasiana from the Bulgarian Black Sea shore have been treated with diesel fuel (100mg l(-1)) in an aquarium with sea-water for three days. The lipids and their fatty acid changes have been examined. Significant changes have been observed mainly in the polar lipids and in the saturation of the fatty acids. These changes appeared to be bigger in the evolutionary less advanced species from both groups of marine organisms--algae and invertebrates (Ulva rigida and Mytilus galloprovincialis respectively). The data obtained could be used for a biomonitoring of the pollution.

Animals↗
PubMed2002

[Effect of symbiotic algae on the photoaccumulation capacity of cells of the ciliate Paramecium bursaria].

The character of the effect produced by symbiotic algae on photodependent behavior of their host ciliates, Paramecium bursaria, was determined. Partially alga-freed paramecia showed a reliable increase in the rates of photoaccumulation. The photoaccumulation rate gradually decreased with a further decrease in the number of zoochlorellae. Once the chlorophyll content fell down to 20-25 mu/l, the ciliates lost their capacity for photoaccululation. A mathematical model of photoaccumulation has been constructed.

Animals↗
PubMed1975

Degradation of urea by bacteria and algae in mass algal cultures.

Studies were conducted to determine the role of bacteria and algae in the degradation of urea in industrial waste waters. The microflora accompanying algae in continuous cultures on waste waters from the nitrogen fertilizers industry was found to include bacteria capable of intensive degradation of urea. Urea hydrolyzing bacteria are with time eliminated from the algal culture. This elimination can be attributed to algal metabolites which inhibit the development of sensitive bacteria. The Chlorella vulgaris strain used in the treatment of wast waters from the nitrogen fertilizers industry did not hydrolyse urea.

Bacteria↗
PubMed2002

Design parameters of high rate algal ponds using filamentous algae matrix for treating rural stream water.

High rate algal ponds (HRAP) with a filamentous algae matrix (FAM) as the predominant species, were operated to evaluate the characteristics of FAM and the basic design parameters for treating polluted rural stream water. The porous and gelatinous FAM was formed like a sponge, which functions to prevent excessive loss of the algae in the effluent and can easily be retrieved from the ponds. The organic fraction of harvested FAM was about 88%, which is suitable for use as fertilizer. The HRAP system using FAM was found to be an effective nutrient removal process not requiring any artificial carbon sources for nitrification. At HRT 4 days, the T-N and T-P removal efficiencies were 85.9% and 65.8%, respectively. When the pH and water temperature were maintained above 9 and 15 degrees C, HRT required for achieving a 70% T-N removal efficiency could be reduced by about 3 days. The oxygen production rate by FAM was calculated as 1.45 mgO2/L/m2. The design surface area of HRAP needed per rural inhabitant was about 2.72 m2.

Agriculture↗
PubMedDate not supplied

[The influence of salinity on the rate of dark respiration and structure of the cells of brown algae thallus from the Barents sea littoral].

We studied the changes in the rate of dark respiration (DR) and structure of the cells in Ascophyllum nodosum and Fucus vesiculosus thalluses during the incubation at 40, 34, 20, 10, and 2@1000 salinity for 14 days. The changes in salinity affect the rate of DR and the structure of the thallus apical cells: the organelles swell and later are destroyed. The effect of decreased salinity on the algae was more pronounced as compared to the increase. The stress intensity directly increased with the rate of desalination. Further adaptation of the algae to low salinity enhanced DR and, hence, was an energy-dependent process. Despite higher DR rates (during the stress and adaptation) in F. vesiculosus as compared to A. nodosum, the seaweeds had similar pattern of adaptation to the changed salinity. Different primary response of the seaweeds to 20@1000 salinity was an important exception; apparently, the salinity around 20@1000 is the limit of these species distribution in desalination zones.

Adaptation, Physiological↗
PubMed2003

[Study on guideline of alga in source water].

Toxic bloom in the sources of drinkable water has been a public health problem. Hindered by the complicated analysis procedure, very limited efforts has been done in investigating toxin level. Patronized by the Chinese Academy of Preventive Medicine, a study on alga hygiene criteria of drinkable water sources in China was conducted. Available literature was reviewed and ecological research and toxicological tests were carried out. The criteria on alga biomass in drinkable water source was formulated by referring the criteria of microcystin--LR in drinking water recommended by WHO and Ministry of Health, China. Three kinds of criteria were worked out: primary criteria, which is to ensure safety, is 1.0 x 10(4) per liter, secondary criteria, which should be alert, is 2.1 x 10(5) per liter, and third--rate criteria, which might be toxic, is 1.2 x 10(6) per liter. It is suggested that these criteria are valuable and feasible in routine work.

Cyanobacteria↗
PubMed2003

[Extinguishment of harmful algae by organo-clay].

Periodic and widespread algal blooms have caused a variety of problems for aquatic life and human activity throughout the world. Currently, the only remedial practice employed for removing algal blooms is to spread clay on the surface of the water. But, the algal removal efficiency by the crude minerals are not really ideal, and how to improve the capability of clays to remove algae is now the technological focus, which also is fatal to the practical value of clays. In this study, hexadecyltrimethyleamine bromide (HDTMAB), one kind of cationic organo-surfactants, was chosen to improve kaolin by surface sorption and cationic exchange, and was tested to remove Prorocentrum donghaiense, a red tide organism in Donghai Sea. The results indicated that organo-clay had an excellent ability to extinguish red tide organisms, even under the application of 0.01 g.L-1, and could subside more than 95% red tide organisms in 24 h. The efficient algae removal by organo-clay might be from the reversal of the surface electric charge on clay particles, the "net capture" by the long lipoid chains of HDTMAB, and the local high density of HDTMAB on particles surface, which could effectively kill algal cells.

Aluminum Silicates↗
PubMedDate not supplied

[Plastidic genome of higher plants and algae: structure and function].

The data on the structure and gene content in completely sequenced plastid (predominantly chloroplast) genomes of higher plants and algae are reviewed. In higher plants, genome structure and gene content are highly conserved. Plastid genomes of algae are less conserved and contain several unique genes, which are not found in chloroplast DNAs of higher plants. Plastid genomes encode proteins involved in transcription and translation, as well as proteins of the photosynthetic apparatus and photosynthetic metabolism. The problems of origin and evolution of plastids are briefly discussed. The data published by the first half of 2002 are presented. Use was made of databases OGMP (http://megasun.bch.umontreal.ca/ogmp/projects/other/cp_list.html) and NCBI (www.ncbi.nlm.nih.gov).

Chloroplasts↗
PubMedDate not supplied

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

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

Cadmium↗
PubMed1999

Comparison of the phenylenediamine isomers bioactivation by the green alga Chlamydomonas reinhardtii.

The correlation between the chemical structure of arylamines meta-, orto-, para-phenylenediamine (m-PDA, o-PDA, p-PDA), and their mutagenic activity is known. It is accepted that these promutagenic compounds are metabolized to ultimate mutagens in mammals and higher plants. In our previous work, we used the alga Chlamydomonas reinhardtii as the activating organism and the bacteria Salmonella typhimurium and yeast Saccharomyces cerevisiae as the genetic indicators for m-PDA activation. In the present work, we used the same activation system for o-PDA and p-PDA activation. Different responses of the yeast and algal wild-type strain and of the repair-deficient strains to the toxic and mutagenic effects of o-PDA and p -PDA were observed. p-PDA had the most toxic effect on both intact yeast and algal cells and in the algal cell/microbe coincubation assays. Concerning repair-deficient algal strains, the recombination-deficient strain was the most sensitive to both compounds tested, indicating that the recombination process played an important role in the DNA repair of arylamines. The rank order of the PDA isomers mutagenicity (including m-PDA) was o-PDA > m-PDA > p-PDA for revertants in intact yeast and forward mutants in algae; m-PDA > o-PDA > p-PDA in the algal cell/S. typhimurium long-term coincubation assay, the algal cell/S. cerevisiae coincubation assay, and the intact S. cerevisiae assay for gene convertants as well.

Animals↗
PubMed2004

[Isolation and effects on green alga Chlorella pyrenoidosa of algal-inhibiting allelochemicals in the macrophyte, Phragmites communis Tris].

Two fractions of secondary metabolites which inhibited the growth of green alga Chlorella pyrenoidosa, was isolated by several separation techniques from the ethanol extract of the macrophyte, Phragmites communis Tris. The EC50 of the two fractions on C. pyrenoidosa were 0.68 mg/L (the fraction of acidic solvent) and 2.65 mg/L (the fraction of alkaline solvent), respectively. Further purification of the allelochemicals in the acidic solvent by alkaline aluminum oxide column chromatography revealed that this fraction containing inhibiting allelochemicals and stimulating allelochemicals. The inhibiting allelochemicals showed more inhibitory effect and the EC50 was 0.50 mg/L. The result suggests that allelochemicals in P. communis can be used as an algae-inhibitor.

Chlorella↗
PubMed2005

[Bromophenols from the brown alga Leathesia nana].

OBJECTIVE: To investigate the chemical constituents of the brown alga Leathesia nana. METHOD: Compounds were isolated by normal phase silica gel, Sephadex LH-20 chromatography and reverse phase HPLC techniques. Their structures were elucidated with spectroscopic methods including IR, MS and NMR. RESULT: Six compounds were isolated from ethanolic extract of the brown alga L. nana and their structures were identified as 2,2',3,3'-tetrabromo-4,4',5,5'-tetrahydroxydiphenyl methane, 2,2',3-tribromo-3', 4,4', 5-tetrahydroxy-6'-ethyloxymethyldiphenyl methane, 2,3-dibromo-4,5-dihydroxybenzyl alcohol, 2,3-dibromo-4,5-dihydroxybenzyl methyl ether, 3-bromo-4-hydroxybenzoic acid and 2-bromo-4,5-dihydroxybenzaldehyde. CONCLUSION: All these compounds were obtained from this species for the first time.

Benzhydryl Compounds↗