Differences between two green algae in biological availability of iron bound to strong chelators

2006 ◽  
Vol 84 (3) ◽  
pp. 400-411 ◽  
Author(s):  
Harold G. Weger ◽  
Carlyn J. Matz ◽  
Rachel S. Magnus ◽  
Crystal N. Walker ◽  
Michael B. Fink ◽  
...  
Keyword(s):  
Green Algae ◽  
Green Alga ◽  
Vascular Plants ◽  
Iron Acquisition ◽  
Algal Species ◽  
Desferrioxamine B ◽  
Green Algal ◽  
Uptake Rates ◽  
Green Alga Chlorella ◽  
Strategy I

N,N′-di(2-hydroxybenzoyl)-ethylenediamine-N,N′-diacetic acid (HBED) is a very strong Fe3+ chelator. Strategy I vascular plants, which use a reductive system for iron acquisition, similar to many green algae, are able to access iron from HBED (R.L. Chaney. 1988. J. Plant Nutr. 11: 1033–1050). However, iron-limited cells of the Strategy I green alga Chlamydomonas reinhardtii Dangeard were unable to access iron present as Fe3+–HBED. In contrast, Fe3+ chelated with hydroxyethylethylenediaminetriacetic acid (HEDTA; a weaker chelator) was rapidly taken up by iron-limited Chlamydomonas cells. Chlamydomonas ferric reduction rates with Fe3+–HBED were approximately 15% of the rate observed with Fe3+–HEDTA, suggesting that low reduction rates with Fe3+–HBED might be one factor in the low rate of iron acquisition. By contrast, iron-limited cells of the Strategy I green alga Chlorella kessleri Fott et Nováková were able to rapidly assimilate Fe3+ chelated by HBED, although ferric reduction rates with Fe3+–HBED were approximately 38% the rate of activity with Fe3+–HEDTA. Similar differential iron uptake rates for the two algal species were obtained using the strong Fe3+ chelator (and siderophore analogue) desferrioxamine B mesylate and the cyanobacterial siderophore schizokinen. These results suggest that there are differences among Strategy I green algae in their abilities to acquire Fe3+ from various ferric chelates: not all Strategy I algae can equally access tightly complexed Fe3+. Chlamydomonas appears to be the first documented Strategy I organism that is unable to acquire iron from Fe3+–HBED. These results also suggest that green algal iron acquisition from siderophores is species dependent. Finally, we suggest that iron acquisition from Fe3+–HBED might serve as an assay for an organisms’ ability to access tightly complexed iron.

High Catalytic Activity of Pd Nanoparticles Synthesized from Green Alga Chlorella vulgaris in Buchwald-hartwig Synthesis of N-Aryl Piperazines

2019 ◽  
Vol 7 (1) ◽  
pp. 23-33
Author(s):  
Vaibhav Mishra ◽  
Anju Arya ◽  
Tejpal Singh Chundawat
Keyword(s):  
Catalytic Activity ◽  
Green Alga ◽  
Chlorella Vulgaris ◽  
Direct Synthesis ◽  
Coupling Reaction ◽  
Pd Nanoparticles ◽  
High Catalytic Activity ◽  
Pd Nanoparticle ◽  
Green Algal ◽  
Green Alga Chlorella

Background: The N-aryl piperazines are an important component of many drug products used for the treatment of malaria, depression, anxiety and Parkinson diseases. Buchwald-Hartwig amination is the latest and well-known reaction for Pd catalyzed direct synthesis of N-aryl piperazine from aryl halides. Although several Pd-ligand systems have already been discovered for this conversion, Pd nanoparticles are recently being used for this useful coupling reaction due to their recyclability and durability. Metal nanoparticles show enhanced catalytic activity compared to their bulk counterparts due to increased surface area at the edges and corners. The use of green algal extract in place of chemical ligands makes this process more environment-friendly and cost-effective. In this research, Pd nanoparticles synthesized using green alga C. Vulgaris were utilized as an alternative approach for the coupling reaction during the preparation of N-aryl piperazines. Methods: Synthesized Pd nanoparticles from C. Vulgaris were characterized by FTIR, SEM and XRD techniques. The catalytic activity of the synthesized nanoparticles was monitored for the synthesis of N-aryl piperazines by Buchwald-Hartwig reaction. The synthesized N-aryl piperazines were characterized by NMR, FTIR and mass analysis. Results: A very good catalytic activity of the synthesized Pd nanoparticles from green alga Chlorella vulgaris extract was observed. The green alga not only reduces the size of the Pd metal to nanoparticles but also acts as a green ligand for reduction of Pd(II) to Pd(0) during nanoparticle synthesis. Using this Pd nanoparticles-green ligand system, several N-aryl piperazines were synthesized in good to excellent yields. Reaction conditions for better conversion were optimized. The comparative advantage of the catalytic system with recently published works on Buchwald-Hartwig C-N coupling reaction is given. Recyclability and durability of the catalyst were explored and the results were found to be promising. A plausible mechanism of Pd nanoparticle catalyzed reaction is also proposed. Conclusion: Catalytic activity of the Pd nanoparticle synthesized from Chlorella vulagris in the synthesis of N-aryl piperazines by Buchwald-Hartwig reaction is reported first time to the best of our knowledge and understanding. The green approach of Pd catalyst to facilitate the reaction and its environmental impact is the main characteristic of the process.

scholarly journals Diacylglyceryl-N,N,N-trimethylhomoserine-dependent lipid remodeling in a green alga, Chlorella kessleri

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Yutaro Oishi ◽  
Rie Otaki ◽  
Yukari Iijima ◽  
Eri Kumagai ◽  
Motohide Aoki ◽  
...  
Keyword(s):  
Green Algae ◽  
Green Alga ◽  
Phosphorus Deficiency ◽  
Membrane Lipid ◽  
Comprehensive Understanding ◽  
Chlorella Kessleri ◽  
Wide Range ◽  
Green Alga Chlorella ◽  
Green Lineage ◽  
Betaine Lipid

AbstractMembrane lipid remodeling contributes to the environmental acclimation of plants. In the green lineage, a betaine lipid, diacylglyceryl-N,N,N-trimethylhomoserine (DGTS), is included exclusively among green algae and nonflowering plants. Here, we show that the green alga Chlorella kessleri synthesizes DGTS under phosphorus-deficient conditions through the eukaryotic pathway via the ER. Simultaneously, phosphatidylcholine and phosphatidylethanolamine, which are similar to DGTS in their zwitterionic properties, are almost completely degraded to release 18.1% cellular phosphorus, and to provide diacylglycerol moieties for a part of DGTS synthesis. This lipid remodeling system that substitutes DGTS for extrachloroplast phospholipids to lower the P-quota operates through the expression induction of the BTA1 gene. Investigation of this lipid remodeling system is necessary in a wide range of lower green plants for a comprehensive understanding of their phosphorus deficiency acclimation strategies.

The Inhibition of Carotenoid Biosynthesis in Green Algae by SANDOZ H 6706: Accumulation of Phytoene and Phytofluene in Chlorella fusca

1975 ◽  
Vol 30 (5-6) ◽  
pp. 333-336 ◽  
Author(s):  
H. W. Kümmel ◽  
L. H. Grimme
Keyword(s):  
Green Algae ◽  
Green Alga ◽  
Control Mechanism ◽  
Carotenoid Biosynthesis ◽  
Chlorella Fusca ◽  
Prolonged Cultivation ◽  
Green Alga Chlorella

Abstract Prolonged cultivation of the green alga Chlorella fusca under heterotrophic conditions and in the presence of sub-lethal concentrations of SAN H 6706 (4-chloro-5-(dimethylamino)-2-(α,α,α-tri-fluoro-m-tolyl)-3 (2H)-pyridazinone) leads to an accumulation of phytoene and phytofluene. The content of chlorophylls and coloured carotenoids of the cells treated with this herbicide, compared with normal untreated cells, is diminished by about 90% and 95% respectively, but the total amount of carotenoids, including colourless phytoene and phytofluene, is increased by 65%. This suggests that SAN H 6706 causes increased accumulation of carotenoids by eliminating a biosynthetic control mechanism, so that the endproducts of the biosynthetic chain no longer control the rate of precursor formation.

scholarly journals Molecular Phylogeny of Unicellular Marine Coccoid Green Algae Revealed New Insights into the Systematics of the Ulvophyceae (Chlorophyta)

2021 ◽  
Vol 9 (8) ◽  
pp. 1586
Author(s):  
Tatyana Darienko ◽  
Cecilia Rad-Menéndez ◽  
Christine N. Campbell ◽  
Thomas Pröschold
Keyword(s):  
Green Algae ◽  
Life Histories ◽  
Phylogenetic Analyses ◽  
Algal Species ◽  
Marine Species ◽  
Life Cycles ◽  
Rdna Sequences ◽  
Green Algal ◽  
The Family ◽  
Chloroplast Formation

Most marine coccoid and sarcinoid green algal species have traditionally been placed within genera dominated by species from freshwater or soil habitats. For example, the genera Chlorocystis and Halochlorococcum contain exclusively marine species; however, their familial and ordinal affinities are unclear. They are characterized by a vegetative cell with lobated or reticulated chloroplast, formation of quadriflagellated zoospores and living epi- or endophytically within benthic macroalgae. They were integrated into the family Chlorochytriaceae which embraces all coccoid green algae with epi- or endophytic life phases. Later, they were excluded from the family of Chlorococcales based on studies of their life histories in culture, and transferred to their newly described order, Chlorocystidales of the Ulvophyceae. Both genera form a “Codiolum”-stage that serves as the unicellular sporophyte in their life cycles. Phylogenetic analyses of SSU and ITS rDNA sequences confirmed that these coccoid taxa belong to the Chlorocystidales, together with the sarcinoid genus Desmochloris. The biflagellated coccoid strains were members of the genus Sykidion, which represented its own order, Sykidiales, among the Ulvophyceae. Considering these results and the usage of the ITS-2/CBC approach revealed three species of Desmochloris, six of Chlorocystis, and three of Sykidion. Three new species and several new combinations were proposed.

Source-dependent variations in organic carbon degradation rates in lake sediments 

2021 ◽  
Author(s):  
Xingguo Han ◽  
Julie Tulo ◽  
Longhui Deng ◽  
Annika Fiskal ◽  
Carsten Schubert ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Lake Sediments ◽  
Green Algae ◽  
Vascular Plants ◽  
Chemical Reactivity ◽  
Vascular Plant ◽  
Decay Rates ◽  
Green Algal ◽  
Degradation Rates ◽  
Eukaryotic Dna

<p>Lake sediments are globally important organic carbon (OC) sinks. Biomolecule chemical reactivity, adsorption and physical shielding have been suggested as important factors in controlling OC degradation rates in sediments. Yet, few studies have investigated the relative importance of these variables, or traced how OC from different organismal sources changes over time due to source-dependent variations in degradation rates.</p><p>We investigate the factors that control organic biomolecule degradation based on analyses of eukaryotic DNA, biomarkers, and (macro)molecule compositions (using pyrolysis-GC/MS) in sediments of five lakes in central Switzerland that differ in trophic state. We specifically target biomolecules of dominant phytoplankton groups (diatoms, green algae), and terrestrial vascular plants. We show that the decay rates of diatom DNA are significantly higher than those of diatom lipid biomarkers and (macro)molecules, consistent with the higher chemical reactivity of DNA. However, the decay rates of green algal DNA and vascular plant DNA are much slower than those of diatom DNA and similar in magnitude to their corresponding membrane lipids and (macro)molecules. In the case of vascular plant biomolecules (DNA, lignin, polyaromatic compounds), no significant biomolecule degradation was detected over the time scales studied (1-5 centuries).</p><p>Our results suggest that chemical reactivity and physical shielding, but not adsorption, are key variables controlling organic biomolecule decay in the lakes studied. In the case of green algae and vascular plants, greater chemical resistance of cell wall structural components to microbial attack appears to facilitate long-term preservation of even highly reactive, intramolecular compounds, such as DNA. These findings have important implications for the use of sedimentary eukaryotic DNA records to reconstruct past environmental changes.</p>

Freshwater green algal biofouling of boats in the Kabul River, Pakistan

2014 ◽  
Vol 43 (4) ◽  
Author(s):  
Izaz Khuram ◽  
Nadeem Ahmad ◽  
Samin Jan ◽  
Sophia Barinova
Keyword(s):  
Statistical Analysis ◽  
Water Temperature ◽  
Green Algae ◽  
Algal Species ◽  
Algal Growth ◽  
Morphological Characteristics ◽  
Temperature Conductivity ◽  
Green Algal ◽  
Significant Stimulation ◽  
Kabul River

AbstractFreshwater green algal biofouling of boats refers to the accrual of freshwater green algae on boats immersed in water. The current research focused on the morphological characteristics of the isolates, species ecology, and the physicochemical properties of the water at the sampling sites. Two localities, Haji Zai and Sardaryab, were sampled at the Kabul River in the district of Charsadda, Pakistan. Freshwater green algae causing biofouling were isolated from the boats. A total of three genera: Cladophora, Rhizoclonium, and Spirogyra with fifteen species belonging to the families Cladophoraceae and Zygnemataceae were observed. Statistical analysis reveals significant stimulation of green algal species in the boats’ fouled communities by increases in water temperature, conductivity, and Total Suspended Solids (TSS). The algal growth at the Haji Zai site is suppressed by TDS in autumn (Pearson −0.56) and is stimulated by water temperature in spring (Pearson 0.44). At the Sardaryab site, algae were stimulated in spring by pH of water (Pearson 0.61), and suppressed by Total Dissolved Solids (TDS) in autumn (Pearson −0.43). Statistical analysis indicates that pH, conductivity, and temperature are the main factors determining the algal biofouling in the Kabul River.

High stability ferric chelates result in decreased iron uptake by the green alga Chlorella kessleri owing to decreased ferric reductase activity and chelation of ferrous iron

Botany ◽  
2009 ◽  
Vol 87 (10) ◽  
pp. 922-931 ◽  
Author(s):  
Harold G. Weger ◽  
Jackie Lam ◽  
Nikki L. Wirtz ◽  
Crystal N. Walker ◽  
Ron G. Treble
Keyword(s):  
Stability Constant ◽  
Green Alga ◽  
Iron Uptake ◽  
High Stability ◽  
Reductase Activity ◽  
Iron Acquisition ◽  
Free Form ◽  
Ferric Reductase ◽  
Chlorella Kessleri ◽  
Green Alga Chlorella

Cells of the green alga Chlorella kessleri Fott et Nováková use a reductive mechanism for iron acquisition. Iron-limited cells acquired iron more rapidly from a chelator with a lower stability constant for Fe3+ (hydroxyethylethylenediaminetriacetic acid (HEDTA)) than from a chelator with a higher stability constant (N,N′-di[2-hydroxybenzyl)ethylenediamine-N,N′-diacetic acid (HBED)). Furthermore, iron uptake rates decreased with increasing chelator concentrations at constant iron concentration. The negative effects of elevated HBED levels on iron uptake could be partly alleviated by the addition of Ga3+, which suggests that iron-free chelator has a negative effect on iron acquisition by competing for Fe2+ with the ferrous transport system. Furthermore, ferric reductase activity progressively decreased with increasing concentrations of both chelators (in the iron-free form). This effect was not alleviated by Ga3+ addition and was apparently caused by the direct inhibition of the reductase. Overall, we conclude that chelators with high stability constants for Fe3+ decrease iron acquisition rates by Strategy I organisms via three separate mechanisms.

scholarly journals Effects of Nutrient Content and Nitrogen to Phosphorous Ratio on the Growth, Nutrient Removal and Desalination Properties of the Green Alga Coelastrum morus on a Laboratory Scale

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2112
Author(s):  
Aida Figler ◽  
Kamilla Márton ◽  
Viktória B-Béres ◽  
István Bácsi
Keyword(s):  
Green Alga ◽  
Nutrient Removal ◽  
Algal Species ◽  
Nutrient Content ◽  
N:P Ratio ◽  
Phosphate Removal ◽  
Nutrient Concentrations ◽  
Nitrate Content ◽  
Green Algal ◽  
N:P Ratios

In wastewater, nutrient concentrations and salinity vary substantially, however, the optimal N:P ratio for the treatment using microalgae is not well described. In this study, the effects of higher and lower nitrate and phosphate contents and N:P ratios on growth, nutrient removal ability and halotolerance of the common green alga Coelastrum morus were investigated in model solutions. The results suggest that high nitrate content (above 100 mg L−1) with a similarly high phosphate concentration (resulting low N:P ratio) is not favorable for growth. The studied isolate can be considered as a halotolerant species, showing remarkable growth up to 1000 mg L−1 NaCl and it seems that despite the negative effects on growth, higher nutrient content contributes to higher halotolerance. A significant amount of nitrate removal was observed in media with different nutrient contents and N:P ratios with different salt concentrations. High N:P ratios favor phosphate removal, which is more inhibited by increasing NaCl concentration than nitrate uptake. Overall, with a relatively higher nutrient content and a favorable (5 or higher) N:P ratio, a common green algal species such as C. morus could be a promising candidate next to species from the Chlorellaceae and Scenedesmaceae families.

Diacylglyceryl-N,N,N-trimethylhomoserine-dependent Lipid Remodeling in a Green Alga, Chlorella Kessleri

2021 ◽  
Author(s):  
Yutaro Oishi ◽  
Rie Otaki ◽  
Yukari Iijima ◽  
Eri Kumagai ◽  
Motohide Aoki ◽  
...  
Keyword(s):  
Green Algae ◽  
Green Alga ◽  
Phosphorus Deficiency ◽  
Membrane Lipid ◽  
Flowering Plants ◽  
Comprehensive Understanding ◽  
Chlorella Kessleri ◽  
Green Alga Chlorella ◽  
Green Lineage ◽  
Betaine Lipid

Abstract Membrane lipid remodeling contributes to environmental 19 acclimation of plants. In a green lineage, a betaine lipid, diacylglyceryl-N,N,N-trimethylhomoserine (DGTS), is included exclusively among green algae and non-flowering plants. Here we show that, a green alga, Chlorella kessleri, reported to exceptionally possess no DGTS, synthesizes it specifically under phosphorus-deficiency conditions through the eukaryotic pathway via the ER. Simultaneously, phosphatidylcholine and phosphatidylethanolamine, which are similar to DGTS in its zwitterionic property, are almost completely degraded to release 18.1% cellular phosphorus, and to provide its diacylglycerol moieties for a part of DGTS synthesis. Above lipid remodeling system that substitutes DGTS for extrachloroplast phospholipids to lower the P-quota operates through expression induction of the gene for BTA1 that is functionally identified as responsible for DGTS synthesis, and those for0 phospholipid breakdown. Investigation of this lipid remodeling is necessary in a widerange of lower green plants for a comprehensive understanding of their phosphorus deficiency acclimation strategies.

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