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At least 73 records · Page 4Linked to original sources

PubMed1968

Fatty acids in blue-green algae: possible relation to phylogenetic position.

Analyses of the lipids in five species of blue-green algae show that the fatty acids are largely the C(16) and C(18) acids. The only alga that could be grown heterotrophically, Chlorogloea, formed the triply unsaturated C(18) acid in the light but only the doubly unsaturated C(18) acid in the dark. Examination of these results and the results of others suggest that, except for one species, the more highly unsaturated acids are found in the morphologically more complex algae. The fatty acid compositions of blue-green algae are different from the fatty acid composition of the other prokaryotic organisms, the bacteria. It is speculated that the diversity of the patterns of fatty acid composition among the blue-green algae could be of phylogenetic significance.

Alkenes↗

PubMed2001

Determination of microcystins in blue-green algae, fish and water using liquid chromatography with ultraviolet detection after sample clean-up employing immunoaffinity chromatography.

Anti-microcystin LR immunnoaffinity cartridges were evaluated for their ability to selectively remove microcystins from extracts of blue-green algae, fish and water samples for subsequent analysis by liquid chromatography with UV absorbance detection at 238 nm. Blue-green algae and fish samples were extracted with 75% methanol in water. A portion of the extract was diluted and passed through an immunoaffinity cartridge. Water samples were applied directly to the cartridge. The cartridge was rinsed with water and 25% methanol in water. The microcystins were eluted with 80% methanol in water containing 4% acetic acid. It was found that the cartridges were effective in isolating the microcystins from blue-green algae, fish and water samples, resulting in extracts that were clean enough to enable direct LC-UV detection down to approximately 0.03 microg/g in the blue-green algae and fish samples, and as low as 0.02 ng/ml for water samples. The cartridges were found to have a capacity of approximately 200 ng each for a mixture of microcystins RR, YR, LR and LA, or as much as 525-800 ng for individual compounds. Recoveries trough the complete analytical procedure ranged from 64 to 115% (all values) with an overall average of approximately 80% at spiking levels of 0.5-4.0 microg/g for the microcystins in blue-green algae. The average recoveries (n=8) from spiked (0.1-0.5 microg/g) fish samples were 73% for RR, 79% for YR, 81% for LR and 77% for LA, while from the spiked (2.0-0.04 ng/g) tap and river water samples (n=6), recoveries were 78% for RR, 86% for YR, 94% for LR and 89% for LA.

Animals↗

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↗

PubMedDate not supplied

[The cultivation of Vibrio cholerae with green algae in an experiment].

Relationships between Vibrio cholerae of different origin and some serogroups with green algae Scenedesmus quadricauda in mineral medium at two temperatures have been experimentally studied. Differences in the relationships of various strains with green algae under the above-mentioned experimental conditions have been established. The study has shown that a decrease in the concentration and the death of vct+ and vct- vibrios of all strains under study occur in the linear phase of the development of algae. 3 V. cholerae strains, serogroups O139 (vct+) and O50 (vct-), have been shown to be capable of survival under the conditions mix cultivation with algae for 50-100 days. The perish of green algae is supposed to increase the survival time and multiplication of V. cholerae under experimental conditions.

Chlorophyta↗

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↗

PubMed1973

Pyridine nucleotide-dependent glucose dehydrogenase activity in blue-green algae.

Pyridine nucleotide-dependent glucose dehydrogenase activity (GPND) is described for the first time in cell-free extracts of certain blue-green algae. When glucose is added to these crude cell extracts, nicotinamide adenine dinucleotide phosphate is reduced at twice the rate as nicotinamide adenine dinucleotide; but evidence suggests that this activity is due to a single enzyme. The distribution and level of GPND in selected blue-green algae correlates with the heterotrophic potential of each species. In all blue-green algae where GPND was detected, O(2) uptake coupled to the GPND reaction was also observed. Both GPND and O(2) uptake apparently occur in the soluble fraction of the cell. An essential role for GPND in the heterotrophic metabolism of blue-green algae is postulated.

Alcohol Oxidoreductases↗

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↗

PubMed2003

Characterization of fragmented mitochondrial ribosomal RNAs of the colorless green alga Polytomella parva.

We have identified previously in mitochondrial DNA of the colorless, chlorophycean, green algal taxon, Polytomella parva, potential coding regions for four small subunit (SSU) and eight large subunit (LSU) rRNA fragments. In this study with P.parva, we isolated RNA from a mitochondrial-enriched preparation, characterized the 12 mitochondrial rRNA transcripts by either northern blot analysis or chemical sequencing and performed secondary structure modeling of the SSU and LSU rRNA sequences. The results show the following features about the mitochondrial SSU and LSU rRNAs of P.parva: (i) they are considerably shorter than their homologs from other green algae, although the main domains typical of conventional rRNAs are conserved; (ii) the rRNA fragmentation pattern is most similar to that of Chlamydomonas reinhardtii among green algae that have been characterized; (iii) three nucleotides are missing from the normally highly conserved GTPase center of the LSU rRNA; and (iv) post-transcriptional modification of the 3'-terminal region of the SSU rRNA is unusual in that it has the 'eubacterial' 3-methyluridine (corresponding to m(3)U at Escherichia coli 16S rRNA position 1498) but lacks the more highly conserved modifications at two adjacent A residues (corresponding to N(6),N(6)-dimethyladenosine at E.coli 16S rRNA positions 1518 and 1519). This is the first report of the characterization by direct sequencing of fragmented mitochondrial rRNAs from a green alga.

Base Sequence↗

PubMed2000

Biologically active steroid from the green alga Ulva lactuca.

The marine green alga, Ulva lactuca, was shown to contain 3-O-beta-D glucopyranosyl-stigmasta-5,25-dien. The structure of the compound was established on the basis of its spectroscopic data and it was extracted for the first time from this alga. The topical antiinflammatory activity of this compound was examined using the mouse ear oedema assay as an experimental model of topical inflammation. Also, the antimicrobial activity of the isolated compound was tested against 10 various microorganisms (G+, G-, fungi and yeast strains).

Administration, Topical↗

PubMed2000

The molecular structure of the fastest myosin from green algae, Chara.

Chara myosin in green algae, Chara corallina, is the fastest myosin of all those observed so far. To shed light on the molecular mechanism of this fast sliding, we determined the primary structure of Chara myosin heavy chain (hc). It has a motor domain, six IQ motifs for calmodulin binding, a coiled-coil structure to dimerize, and a globular tail. Chara myosin hc is very similar to some plant myosins and has been predicted to belong to the class XI. Short loop 1 and loop 2 may account for the characteristics of mechanochemical properties of Chara myosin.

Amino Acid Sequence↗

PubMed2002

Kinesin-like proteins are involved in postmitotic nuclear migration of the unicellular green alga Micrasterias denticulata.

The unicellular green alga Micrasterias denticulata performs a two-directional postmitotic nuclear migration during development, a passive migration into the growing semicell, and a microtubule mediated backward migration towards the cell centre. The present study provides first evidence for force generation by motor proteins of the kinesin family in this process. The new kinesin specific inhibitor adociasulfate-2 causes abnormal nuclear displacement at 18 microM. AMP-PNP, a non hydrolyseable ATP analogue or the general ATPase inhibitors calyculin A and sodium orthovanadate also disturb nuclear migration. In addition kinesin-like proteins are detected by means of immunoblotting using antibodies against brain kinesin, plant derived antibodies to kinesin-like proteins and a calmodulin binding kinesin-like protein. Immunoelectron microscopy suggests a correlation of conventional kinesin-like proteins, but not of the calmodulin binding kinesin-like protein to the microtubule apparatus associated with the migrating nucleus.

Adenosine Triphosphatases↗

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↗

PubMed2006

Up-regulation of photoprotection and PSII-repair gene expression by irradiance in the unicellular green alga Dunaliella salina.

The unicellular green alga Dunaliella salina is an attractive model organism for studying photoacclimation responses and the photosystem II (PSII) damage and repair process in the photosynthetic apparatus. Irradiance during cell growth defines both the photoacclimation and the PSII repair status of the cells. To identify genes specific to these processes, a cDNA library was created from irradiance-stressed D. salina. From the cDNA library, 1112 randomly selected expressed sequence tags (ESTs) were analyzed. Because ESTs constitute the expressed part of the genome, the strategy of randomly sequencing cDNA clones at their 5'-ends allowed us to obtain information about the transcript level of numerous genes in light-stressed D. salina. The results of a BLASTX search performed on the obtained total set of ESTs showed that approximately 1% of the ESTs could be assigned to genes coding for proteins that are known to be up-regulated in response to high-light stress. Specifically, after 48 h of high-light exposure of the cells, an increase in the expression level of antioxidant genes, such as Fe-SOD and APX, was observed, as well as elevated levels of the Cbr transcript, a light-harvesting Chl-protein homolog. Further, the ATP-dependent Clp protease gene was also up-regulated in D. salina cells after 48 h of exposure to high light. The results provide initial insight into the global gene regulation process in response to irradiance.

Algal Proteins↗

PubMed2007

Photometrical analysis with photosensory domains of photoreceptors in green algae.

Chloroplast photoorientation in the green alga Mougeotia scalaris is controlled by blue and red light. The properties of the LOV domains of phototropin A and B were consistent with previous data of action spectra and photoreceptor lifetime for blue light-mediated photoorientation. The LOV domains of the neochromes did not bind flavin, while the domains of neochrome 2 contributed to multimer formation. The absorption spectra of the neochrome phytochrome photosensory domain with phytochromobilin were very similar to the action spectra for red light-induced photoorientation. These results indicate that phototropin and neochrome work as the blue and red photoreceptors involved in photoorientation.

Algal Proteins↗

PubMed2005

Stress-related differential expression of multiple beta-carotene ketolase genes in the unicellular green alga Haematococcus pluvialis.

The unicellular green alga Haematococcus pluvialis is used as a biological production system for astaxanthin. It accumulates large amounts of this commercially interesting ketocarotenoid under a variety of environmental stresses. Here we report the identification and expression of three different beta-carotene ketolase genes (bkt) that are involved in the biosynthesis of astaxanthin in a single strain of the alga. Bkt1 and bkt2 proved to be the crtO and bkt previously isolated from two different strains of H. pluvialis. Bkt3 is a novel third gene, which shared 95% identical nucleotide sequence with bkt2. Nitrogen deficiency alone could not induce the alga cells to produce astaxanthin in 3 days even though it enhances the expression of the bkt genes to three times of that in normal growing cells within 16 h. High light irradiation (125 micromol m(-2)s(-1)) or 45 mM sodium acetate greatly increased the expression of bkt genes to 18 or 52 times of that in normal growing cells, resulting in an accumulation of substantial astaxanthin (about 6 mg g(-1) dry biomass) in 3 days. It is suggested that the existence of the multiple bkt genes and their strong up-regulation by different stress conditions is one of the reasons that H. pluvialis accumulates large amounts of astaxanthin in an instant response to stress environments.

Base Sequence↗

PubMed1998

Molecular characterization of a single mitochondria-associated double-stranded RNA in the green alga Bryopsis.

Mitochondria from the green alga Bryopsis sp. very often contained a 4.5 kb double-stranded RNA (dsRNA) at a defined level. Complementary DNA probes derived from the mitochondrial dsRNA hybridized with none of the algal chloroplast dsRNAs of 1.7 to 2.2 kb, but did hybridize with a similar-sized dsRNA among several dsRNAs from the mitochondria of B. maxima. Sequence analysis of the mitochondrial dsRNA from Bryopsis sp. revealed only two large, overlapping, open reading frames (ORFs) on one strand if UGA was taken as a non-termination codon, suggesting the independent phylogenetic evolution of the mitochondrial dsRNA. Consensus sequence for RNA-dependent RNA polymerase was found within the longer ORF (2472 bp) of the dsRNA. The overlapping 52 bp of the ORFs in different reading frames is suggestive of the occurrence of a -1 ribosomal frameshift in the mitochondrial translation system. The observed simple genetic structures suggest that the algal mitochondrial dsRNA might be deficient in a gene for movement from cell to cell in host plants and, hence, has a plasmid-like nature that is distinct from that of infectious plant viruses. The nature and origin of the endogenous dsRNAs of various sizes and their relationships are discussed.

Amino Acid Sequence↗

PubMed2005

The exceptional photofermentative hydrogen metabolism of the green alga Chlamydomonas reinhardtii.

The photosynthetic green alga Chlamydomonas reinhardtii is capable of performing a complex fermentative metabolism which is related to the mixed acid fermentation of bacteria such as Escherichia coli. The fermentative pattern includes the products formate, ethanol, acetate, glycerol, lactate, carbon dioxide and molecular hydrogen (H(2)). H(2) production is catalysed by an active [Fe]-hydrogenase (HydA) which is coupled with the photosynthetic electron-transport chain. The most important enzyme of the classic fermentation pathway is pyruvate formate-lyase, which is common in bacteria but seldom found in eukaryotes. An interaction between fermentation, photosynthesis and H(2) evolution allows the algae to overcome long periods of anaerobiosis. In the absence of sulphur, the cells establish a photofermentative metabolism and accumulate large amounts of H(2).

Animals↗

PubMed2000

Cytoskeleton mediating transport between the ER system and the Golgi apparatus in the green alga Scenedesmus acutus.

In the green alga Scenedesmus acutus, Golgi bodies are located near the nucleus and supplied with transition vesicles that bud from the outer nuclear envelope membrane. Using this alga, we have shown previously that thiamine pyrophosphatase (TPPase), a marker enzyme of Golgi bodies, migrates in vesicles from the Golgi bodies to the ER via the nuclear envelope in the presence of BFA (Noguchi et al., Protoplasma 201, 202-212, 1998). In this study we demonstrate that both cytochalasin B and oryzalin (microtubule-disrupting agent) inhibit the BFA-induced migration of TPPase from Golgi bodies to the nuclear envelope. However, only actin filaments--not microtubules--can be detected between the nuclear envelope and the Golgi bodies in both BFA-treated and untreated cells. These observations suggest that actin filaments mediate the BFA-induced retrograde transport of vesicles. This mechanism differs from that found in mammalian cells, in which microtubules mediate BFA-induced retrograde transport by the elongation of membrane tubules from the Golgi cisternae. We also discuss the non-participation of the cytoskeleton in anterograde transport from the nuclear envelope to the Golgi bodies.

Antifungal Agents↗