scholarly journals Intermediates of tocopherol biosynthesis in the unicellular alga Scenedesmus obliquus. The presence of three isomeric methylphytylbenzoquinones

1987 ◽  
Vol 242 (2) ◽  
pp. 367-373 ◽  
Author(s):  
A Henry ◽  
R Powls ◽  
J F Pennock
Keyword(s):  
Carbon Atom ◽  
Hydroxy Group ◽  
Scenedesmus Obliquus ◽  
Alpha Tocopherol ◽  
Unicellular Alga ◽  
Unicellular Algae

Three isomers of methylphytylbenzoquinone have been isolated from lipids of the unicellular alga Scenedesmus obliquus, the most abundant being 2-methyl-6-phytylbenzoquinone (65% of the total). The 2-methyl-3-phytyl and 2-methyl-5-phytyl isomers amounted to 8 and 27% respectively. Previously problems have been encountered in the separation of the 3-phytyl and the 6-phytyl isomers, but in the present study it was found that they separated readily as quinols. Phytyl plastoquinone was also found and the relevance of these compounds to the biosynthesis of alpha-tocopherol is discussed. As well as phylloquinone, a hydroxyphylloquinone was detected, and studies indicated that it is the 5′ carbon atom to which the hydroxy group is attached. Such a compound has been found by workers using other unicellular algae.

scholarly journals Alien domains shaped the modular structure of plant NLR proteins

2019 ◽  
Author(s):  
Giuseppe Andolfo ◽  
Antimo Di Donato ◽  
Pasquale Chiaiese ◽  
Antonino De Natale ◽  
Antonino Pollio ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Cell Surface ◽  
Surveillance System ◽  
Genomic Structure ◽  
Defense Responses ◽  
Leucine Rich Repeat ◽  
Unicellular Alga ◽  
Unicellular Algae ◽  
A Cell ◽  
Chromochloris Zofingiensis

Abstract Plant innate immunity mostly relies on nucleotide-binding (NB) and leucine-rich repeat (LRR) intracellular receptors to detect pathogen-derived molecules and to induce defense responses. A multi-taxa reconstruction of NB-domain associations allowed us to identify the first NB-LRR arrangement in the Chlorophyta division of the Viridiplantae. Our analysis points out that the basic NOD-like receptor (NLR) unit emerged in Chlorophytes by horizontal transfer and its diversification started from TIR-NB-LRR (TNL) members. The operon-based genomic structure of Chromochloris zofingiensis NLR copies suggests a functional origin of NLR clusters. Moreover, the transmembrane signatures of NLR proteins in the unicellular alga C. zofingiensis supports the hypothesis that the NLR-based immunity system of plants derives from a cell-surface surveillance system. Taken together, our findings suggest that NLRs originated in unicellular algae and may have a common origin with cell surface LRR receptors.

Arsenolipid biosynthesis by the unicellular alga Dunaliella tertiolecta is influenced by As/P ratio in culture experiments

Metallomics ◽  
2018 ◽  
Vol 10 (1) ◽  
pp. 145-153 ◽  
Author(s):  
Ronald A. Glabonjat ◽  
Josef Ehgartner ◽  
Elliott G. Duncan ◽  
Georg Raber ◽  
Kenneth B. Jensen ◽  
...  
Keyword(s):  
Dunaliella Tertiolecta ◽  
Water Soluble ◽  
Unicellular Alga ◽  
Unicellular Algae

Culture experiments exposing unicellular algae to varying arsenate/phosphate regimes and determining their arsenometallomes by HPLC–MS shows the interconnection of arsenolipids and water-soluble arsenicals.

scholarly journals Homopropargyl alcohol 5,5-diphenylpent-2-yne-1,5-diol

IUCrData ◽  
2018 ◽  
Vol 3 (11) ◽  
Author(s):  
Christian A. Umaña ◽  
Leslie W. Pineda ◽  
Jorge A. Cabezas
Keyword(s):  
Hydrogen Bonding ◽  
Carbon Atom ◽  
Hydroxy Group ◽  
Title Compound ◽  
Tetrahedral Geometry ◽  
Central Carbon Atom ◽  
Distorted Tetrahedral Geometry ◽  
Compound C ◽  
Hydrogen Bonding Interactions ◽  
Central Carbon

In the title compound, C17H16O2, the central carbon atom has a distorted tetrahedral geometry [spread of angles = 105.71 (8)–112.75 (9)°] for its bonds to a homopropargylic but-2-yn-1-ol moiety, a hydroxy group and two phenyl substituents. In the crystal, O—H...O hydrogen-bonding interactions link the molecules into [001] chains and C—H...π(ring) contacts consolidate the packing.

scholarly journals Marine and freshwater micropearls: biomineralization producing strontium-rich amorphous calcium carbonate inclusions is widespread in the genus <i>Tetraselmis</i> (Chlorophyta)

2018 ◽  
Vol 15 (21) ◽  
pp. 6591-6605 ◽  
Author(s):  
Agathe Martignier ◽  
Montserrat Filella ◽  
Kilian Pollok ◽  
Michael Melkonian ◽  
Michael Bensimon ◽  
...  
Keyword(s):  
Unicellular Alga ◽  
Amorphous Calcium Carbonate ◽  
Surrounding Water ◽  
Calcium Carbonates ◽  
Mineral Inclusions ◽  
Biomineralization Process ◽  
Unicellular Algae ◽  
Carbon Pump ◽  
Definite Pattern ◽  
Widespread Phenomenon

Abstract. Unicellular algae play important roles in the biogeochemical cycles of numerous elements, particularly through the biomineralization capacity of certain species (e.g., coccolithophores greatly contributing to the “organic carbon pump” of the oceans), and unidentified actors of these cycles are still being discovered. This is the case of the unicellular alga Tetraselmis cordiformis (Chlorophyta) that was recently discovered to form intracellular mineral inclusions, called micropearls, which had been previously overlooked. These intracellular inclusions of hydrated amorphous calcium carbonates (ACCs) were first described in Lake Geneva (Switzerland) and are the result of a novel biomineralization process. The genus Tetraselmis includes more than 30 species that have been widely studied since the description of the type species in 1878. The present study shows that many other Tetraselmis species share this biomineralization capacity: 10 species out of the 12 tested contained micropearls, including T. chui, T. convolutae, T. levis, T. subcordiformis, T. suecica and T. tetrathele. Our results indicate that micropearls are not randomly distributed inside the Tetraselmis cells but are located preferentially under the plasma membrane and seem to form a definite pattern, which differs among species. In Tetraselmis cells, the biomineralization process seems to systematically start with a rod-shaped nucleus and results in an enrichment of the micropearls in Sr over Ca (the Sr∕Ca ratio is more than 200 times higher in the micropearls than in the surrounding water or growth medium). This concentrating capacity varies among species and may be of interest for possible bioremediation techniques regarding radioactive 90Sr water pollution. The Tetraselmis species forming micropearls live in various habitats, indicating that this novel biomineralization process takes place in different environments (marine, brackish and freshwater) and is therefore a widespread phenomenon.

New insights into the effects of the herbicide imazethapyr on Cu(II) ecotoxicity to the aquatic unicellular alga Scenedesmus obliquus

2013 ◽  
Vol 140-141 ◽  
pp. 407-414 ◽  
Author(s):  
Hui Chen ◽  
Xiaolin Sheng ◽  
Yuezhong Wen ◽  
Lijuan Zhang ◽  
Hongliang Bao ◽  
...  
Keyword(s):  
Scenedesmus Obliquus ◽  
Unicellular Alga

scholarly journals Distribution of the mevalonate and glyceraldehyde phosphate/pyruvate pathways for isoprenoid biosynthesis in unicellular algae and the cyanobacterium Synechocystis PCC 6714

1998 ◽  
Vol 333 (2) ◽  
pp. 381-388 ◽  
Author(s):  
Andrea DISCH ◽  
Jörg SCHWENDER ◽  
Christian MÜLLER ◽  
Hartmut K. LICHTENTHALER ◽  
Michel ROHMER
Keyword(s):  
Higher Plants ◽  
Scenedesmus Obliquus ◽  
Growth Conditions ◽  
Isoprenoid Biosynthesis ◽  
Mva Pathway ◽  
Feeding Experiments ◽  
Ochromonas Danica ◽  
Unicellular Algae ◽  
Β Carotene ◽  
Synechocystis Pcc 6714

Isopentenyl diphosphate, the universal isoprenoid precursor, can be produced by two different biosynthetic routes: either via the acetate/mevalonate (MVA) pathway, or via the more recently identified MVA-independent glyceraldehyde phosphate/pyruvate pathway. These two pathways are easily differentiated by incorporation of [1-13C]glucose and analysis of the resulting labelling patterns found in the isoprenoids. This method was successfully applied to several unicellular algae raised under heterotrophic growth conditions and allowed for the identification of the pathways that were utilized for isoprenoid biosynthesis. All isoprenoids examined (sterols, phytol, carotenoids) of the green algae Chlorella fusca and Chlamydomonas reinhardtii were synthesized via the GAP/pyruvate pathway, as in another previously investigated green alga, Scenedesmus obliquus, which was also shown in this study to synthesize ubiquinone by the same MVA-independent route. In the red alga Cyanidium caldarium and in the Chrysophyte Ochromonas danica a clear dichotomy was observed: as in higher plants, sterols were formed via the MVA route, whereas chloroplast isoprenoids (phytol in Cy. caldariumand O. danica and β-carotene in O. danica) were synthesized via the GAP/pyruvate route. In contrast, the Euglenophyte Euglena gracilis synthesized ergosterol, as well as phytol, via the acetate/MVA route. Similar feeding experiments were performed with the cyanobacterium SynechocystisPCC 6714 using [1-13C]- and [6-13C]-glucose. The two isoprenoids examined, phytol and β-carotene, were shown to have the typical labelling pattern derived from the GAP/pyruvate route.

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