713 research outputs found

    Chloroplast damage induced by the inhibition of fatty acid synthesis triggers autophagy in chlamydomonas

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    Fatty acids are synthesized in the stroma of plant and algal chloroplasts by the fatty acid synthase complex. Newly synthesized fatty acids are then used to generate plastidial lipids that are essential for chloroplast structure and function. Here, we show that inhibition of fatty acid synthesis in the model alga Chlamydomonas reinhardtii activates autophagy, a highly conserved catabolic process by which cells degrade intracellular material under adverse conditions to maintain cell homeostasis. Treatment of Chlamydomonas cells with cerulenin, a specific fatty acid synthase inhibitor, stimulated lipidation of the autophagosome protein ATG8 and enhanced autophagic flux. We found that inhibition of fatty acid synthesis decreased monogalactosyldiacylglycerol abundance, increased lutein content, down-regulated photosynthesis, and increased the production of reactive oxygen species. Electron microscopy revealed a high degree of thylakoid membrane stacking in cerulenin-treated cells. Moreover, global transcriptomic analysis of these cells showed an up-regulation of genes encoding chloroplast proteins involved in protein folding and oxidative stress and the induction of major catabolic processes, including autophagy and proteasome pathways. Thus, our results uncovered a link between lipid metabolism, chloroplast integrity, and autophagy through a mechanism that involves the activation of a chloroplast quality control system.Ministerio de Economía y Competitividad BFU2015-68216-PJunta de Andalucía CVI-7336, BIO2015-74432-JI

    Phosphorus Availability Regulates TORC1 Signaling via LST8 in Chlamydomonas

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    Target of rapamycin complex 1 (TORC1) is a central regulator of cell growth. It balances anabolic and catabolic processes in response to nutrients, growth factors, and energy availability. Nitrogen- and carbon-containing metabolites have been shown to activate TORC1 in yeast, animals, and plants. Here, we show that phosphorus (P) regulates TORC1 signaling in the model green alga Chlamydomonas (Chlamydomonas reinhardtii) via LST8, a conserved TORC1 subunit that interacts with the kinase domain of TOR. P starvation results in a sharp decrease in LST8 abundance and downregulation of TORC1 activity. A hypomorphic lst8 mutation resulted in decreased LST8 abundance, and it both reduced TORC1 signaling and altered the cellular response to P starvation. Additionally, we found that LST8 levels and TORC1 activity were not properly regulated in a mutant defective in the transcription factor PSR1, which is the major mediator of P deprivation responses in Chlamydomonas. Unlike wild-type cells, the psr1 mutant failed to downregulate LST8 abundance and TORC1 activity when under P limitation. These results identify PSR1 as an upstream regulator of TORC1 and demonstrate that TORC1 is a key component in P signaling in Chlamydomonas.España Ministerio de Economía y Competitividad (grants BFU2015-68216-P and PGC2018-099048- B-100 to J.L.C. and grant BIO2015-74432-JIN to M.E.P.-P.)National Science Foundation (CAREER award MCB-1552522 to L.M.H. and grant MCB-1616820 to J.G.U.)European Commission (grant number 750996

    Results of the Spanish survey in NAFO Division 3NO

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    Greenland halibut (Reinhardtius hippoglossoides), American plaice (Hippoglossoides platessoides), Atlantic cod (Gadus morhua), yellowtail flounder (Limanda ferruginea), redfish (Sebastes spp.), witch flounder (Glyptocephalus cynoglossus), roughhead grenadier (Macrourus berglax), thorny skate (Amblyraja radiata), white hake (Urophycis tenuis), squid (Illex illecebrosus) and capelin (Mallotus villosus) indices from the bottom trawl survey that Spain carries out in Spring since 1995 in Divisions 3NO of the NAFO Regulatory Area are presented. In 2020, the survey was not carried out due to the COVID pandemic situation. The presented indices are biomass by stratum, total length distribution and a and b parameters for the length-weight relationship; age distribution is also presented for Greenland halibut, Atlantic cod and American plaice.Versión del editor

    Spanish Research Report for 2017

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    Spanish catch and effort information used in this Report is based on the logbook data contributed by the Spanish Administration. The logbooks information for 2017 was available haul by haul. Table 1 presents the Spanish catches by species and Division in 2017 in NAFO Regulatory Area. Total effort of the Spanish fleet in 2017 was 1,037 fishing days. In 2017, IEO scientific observers were on board 329 fishing days that it means 32 % of the Spanish total effort. All length, age and biological information presented in this paper is based on sampling carried out by IEO scientific observers. In 2017, 483 samples were taken with 57,988 individuals of different species examined (Table 2)

    Results for Greenland halibut, American plaice and Atlantic cod of the Spanish survey in NAFO Div. 3NO for the period 1997-2019

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    Greenland halibut (Reinhardtius hippoglossoides), American plaice (Hippoglossoides platessoides) and Atlantic cod (Gadus morhua) indices from the bottom trawl survey that Spain carries out in Spring since 1995 in Div. 3NO of the NAFO Regulatory Area are presented. Biomass, stratified mean catches and mean number per tow for the three species are presented since 1997, year in which the survey extended the depth strata. Mean catch per tow, length distribution and age distribution (this last except for American plaice) are presented for the last five years (2015-2019). Greenland halibut biomass and abundance estimates presented a decreasing trend since 1999, cut in 2007- 2009 with a high increase. In 2011 the biomass drops under the 2008 value, being stable since then until 2014 with a slight increase in 2015-2019 comprising a big increase in 2017, reaching the maximum of the series. In last years it can be seen a presence of juveniles, mainly in 2004, but the greatest lengths have failed, although in 2009 there is a quite good presence of individuals of ages 6-7 and in 2010 between 5-7. In 2011-2019 the presence of all ages is poor. In 2018 the mode was at 1-2 years, and 2-3 years in 2019, suggesting a fairly strong 2017 cohort. For American plaice we can see a slightly increasing trend from 1999 to 2015, reaching a maximum of mean catch and number in 2006, and a severe decline since 2016, being the 2019 the lowest value of the entire series. The greatest recruitment in the presented series occurred in 2004 and we can follow their mode along the years. No good recruitments were seen since then. In last years the level of all the ages is low. No 2019 age indices are available at this moment. For Atlantic cod, it can be seen a low biomass until 2008, being higher and variable since then, reaching a historical maximum in 2014. From 2015, biomass decreased reaching in 2019 poor values at the level of the 2005 biomass. In 2007-2008 the youngest length classes were much over the rest of the length classes. With the 2006 cohort the series reaches the maximum number of its historical values at five years in 2011. There have been no good recruitments since 2009, although in 2015 and 2016 a discrete presence of individuals of age 1 can be seen

    The analysis of meiosis of the B genome of common wheat.

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    6 p.Two intervarietal hybrids of common wheat, Triticum aestivum L., are meiotically analyzed using the C-banding staining method. The C-banding pattern of nine meiotic chromosomes (4A, 7A, and the seven of the B genome) permitted their unequivocal recognition at first metaphase plates. The pairing frequency of each B-genome chromosome arm was scored. Data on the pairing frequency of the arms, separately considered, are applied to calculate expected pairing of whole chromosomes and whole genomes. The application of mathematical models to predict the genome pairing using either equal or different frequencies per chromosome arm is discussed.Key words: meiotic analysis, Triticum aestivum L., C-banding

    Microwave-assisted Palladium catalysed C-H acylation with aldehydes. Synthesis and diversification of 3-acylthiophenes

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    The use of MW allows the efficient palladium(II)-catalysed C-3 acylation of thiophenes with aldehydes via C(sp2)-H activation for the synthesis of (cyclo)alkyl/aryl thienyl ketones (43 examples). Compared to standard thermal conditions, the use of MW reduces the reaction time (15 to 30 min vs. 1 to 3 hours), leading to improved yields of the ketones (up to 92%). Control of positional selectivity is achieved by 2-pyridinyl and 2-pyrimidyl ortho-directing groups at C-2 of the thiophene scaffold. To show the synthetic applicability, selected ketones were subjected to further transformations, including intramolecular reactions to directly embed the directing-group in the core-structure of the new moleculeMinisterio de Ciencia e Innovación (PID2019-104148GB-I00) / Gobierno Vasco (IT1045-16

    Fe(II) complexes of pyridine-substituted thiosemicarbazone ligands as catalysts for oxidations with hydrogen peroxide

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    La reacción de tres complejos [FeII(TSC)2], donde TSC es una ligando de tipo tiosemicarbazona sustituido por piridina, con H2O2 en acetonitrilo no permitía acumular los correspondientes complejos de Fe(III), [FeIII(TSC)2]+. En su lugar, se generaba una mezcla de especies de Fe(II) diamagnéticas de bajo espín. Según los espectros obtenidos por espectrometría de masas, estas especies eran el resultado de la adición secuencial de hasta cinco átomos de oxígeno al complejo. Esta capacidad para la adición de átomos de oxígeno sugirió que dichas especies podrían ser activas para la transferencia de átomos de oxígeno a sustratos externos. Por ello, se evaluó la capacidad de estos complejos para la oxidación de tioanisol y estireno empleando H2O2 como oxidante inicial. Los complejos fueron activos tanto en la oxidación de tioanisol a su sulfóxido como en la de estireno a benzaldehído, con escalas temporales que indicaban la participación de las especies intermedias que contenían los átomos de oxígeno añadidos. Curiosamente, los ligandos libres y el complejo [Zn(Dp44mT)2] también catalizaban la sulfoxidación selectiva del tioanisol, pero eran ineficaces para catalizar la oxidación del estireno a benzaldehído. Estos hallazgos abren nuevas vías para el desarrollo de catalizadores metálicos basados en tiosemicarbazonas en procesos de oxidación de gran interés
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