Measurement of Lipid Transport in Mitochondria by the MTL Complex.

Membrane biogenesis requires an extensive traffic of lipids between different cell compartments. Two main pathways, the vesicular and non-vesicular pathways, are involved in such a process. Whereas the mechanisms involved in vesicular trafficking are well understood, less is known about non-vesicular lipid trafficking, particularly in plants.

Marine emissions of methanethiol increase aerosol cooling in the Southern Ocean.

Ocean-emitted dimethyl sulfide (DMS) is a major source of climate-cooling aerosols. However, most of the marine biogenic sulfur cycling is not routed to DMS but to methanethiol (MeSH), another volatile whose reactivity has hitherto hampered measurements. Therefore, the global emissions and climate impact of MeSH remain unexplored.

Monogalactosyldiacylglycerol synthase isoforms play diverse roles inside and outside the diatom plastid.

Diatoms derive from a secondary endosymbiosis event, which occurred when a eukaryotic host cell engulfed a red alga. This led to the formation of a complex plastid enclosed by four membranes: two innermost membranes originating from the red alga chloroplast envelope, and two additional peri- and epiplastidial membranes (PPM, EpM). The EpM is linked to the endoplasmic reticulum (ER).

Stress-Induced Production of Bioactive Oxylipins in Marine Microalgae.

Microalgae, stemming from a complex evolutionary lineage, possess a metabolic composition influenced by their evolutionary journey. They have the capacity to generate diverse polyunsaturated fatty acids (PUFAs), akin to those found in terrestrial plants and oily fish. Also, because of their numerous double bonds, these metabolic compounds are prone to oxidation processes, leading to the creation of valuable bioactive molecules called oxylipins.

Complementary environmental analysis and functional characterization of lower glycolysis-gluconeogenesis in the diatom plastid.

Organic carbon fixed in chloroplasts through the Calvin-Benson-Bassham Cycle can be diverted toward different metabolic fates, including cytoplasmic and mitochondrial respiration, gluconeogenesis, and synthesis of diverse plastid metabolites via the pyruvate hub. In plants, pyruvate is principally produced via cytoplasmic glycolysis, although a plastid-targeted lower glycolytic pathway is known to exist in non-photosynthetic tissue. Here, we characterized a lower plastid glycolysis-gluconeogenesis pathway enabling the direct interconversion of glyceraldehyde-3-phosphate and phospho-enol-pyruvate in diatoms, ecologically important marine algae distantly related to plants.

Quantitative Assessment of the Chloroplast Lipidome.

In plants and algae, photosynthetic membranes have a unique lipid composition. They differ from all other cellular membranes by their very low amount of phospholipids, besides some phosphatidylglycerol (PG), and high proportion of glycolipids. These glycolipids are the uncharged galactolipids, that is, mono- and digalactosyldiacylglycerol (MGDG and DGDG), and an anionic sulfolipid, that is, sulfoquinovosyldiacylglycerol (SQDG).

Extraction and Quantification of Lipids from Plant or Algae.

In plants and algae, the glycerolipidome changes in response to environmental modifications. For instance, in phosphate starvation, phospholipids are degraded and replaced by non-phosphorus lipids, and in nitrogen starvation, storage lipids accumulate. In addition to the well-known applications of oil crops for food, algae lipids are becoming a model for potential applications in health, biofuel, and green chemistry and are used as a platform for genetic engineering.

A Gradient-Descent Optimization of CO-CO-NO Emissions over the Paris Megacity─The Case of the First SARS-CoV-2 Lockdown.

Urban greenhouse gas emissions monitoring is essential to assessing the impact of climate mitigation actions. Using atmospheric continuous measurements of air quality and carbon dioxide (CO), we developed a gradient-descent optimization system to estimate emissions of the city of Paris. We evaluated our joint CO-CO-NO optimization over the first SARS-CoV-2 related lockdown period, resulting in a decrease in emissions by 40% for NO and 30% for CO, in agreement with preliminary estimates using bottom-up activity data yet lower than the decrease estimates from Bayesian atmospheric inversions (50%).

NO, BC and PM Exposure of Participants in the Polluscope Autumn 2019 Campaign in the Paris Region.

The Polluscope project aims to better understand the personal exposure to air pollutants in the Paris region. This article is based on one campaign from the project, which was conducted in the autumn of 2019 and involved 63 participants equipped with portable sensors (i.e.

New particle formation at a peri-urban agricultural site.

New Particle Formation (NPF) is a major source of ultrafine particles that affect both air quality and climate. Despite emissions from agricultural activities having a strong potential to lead to NPF, little is known about NPF within agricultural environments. The aim of the present study was to investigate the occurrence of NPF events at an agricultural site, and any potential relationship between agricultural emissions and NPF events.

Personal Exposure to Black Carbon, Particulate Matter and Nitrogen Dioxide in the Paris Region Measured by Portable Sensors Worn by Volunteers.

Portable sensors have emerged as a promising solution for personal exposure (PE) measurement. For the first time in Île-de-France, PE to black carbon (BC), particulate matter (PM), and nitrogen dioxide (NO) was quantified based on three field campaigns involving 37 volunteers from the general public wearing the sensors all day long for a week. This successful deployment demonstrated its ability to quantify PE on a large scale, in various environments (from dense urban to suburban, indoor and outdoor) and in all seasons.

Variability and sources of non-methane hydrocarbons at a Mediterranean urban atmosphere: The role of biomass burning and traffic emissions.

Levels and sources of non-Methane Hydrocarbons (NMHCs) were investigated at the urban background Thissio station, close to the historical center of Athens (Greece) from March 2016 to February 2017 (12 months), by means of an automated GC-FID. Alkanes dominated over aromatics and alkenes, with hourly mean levels ranging from detection limit up to 60 μg m for i-pentane and 90 μg m for toluene. Higher levels were recorded in the cold period relative to the warmer one.

Consequences of Mixotrophy on Cell Energetic Metabolism in Revealed by Genetic Engineering and Metabolic Approaches.

Algae belonging to the genus are promising organisms for biotech purposes, being able to accumulate large amounts of lipid reserves. These organisms adapt to different trophic conditions, thriving in strict photoautotrophic conditions, as well as in the concomitant presence of light plus reduced external carbon as energy sources (mixotrophy). In this work, we investigated the mixotrophic responses of (formerly ).

Atmospheric reactivity of biogenic volatile organic compounds in a maritime pine forest during the LANDEX episode 1 field campaign.

Trace gas measurements were performed during the LANDEX (the LANDes EXperiment) Episode 1 field campaign in the summer 2017, in one of the largest European maritime pine forests (> 95% Pinus pinaster) located in southwestern France. Efforts have been focused on obtaining a good speciation of 20 major biogenic volatile organic compounds (BVOCs, including pinenes, carenes, terpinenes, linalool, camphene, etc.).

Atmospheric Biodetection Part I: Study of Airborne Bacterial Concentrations from January 2018 to May 2020 at Saclay, France.

The monitoring of bioaerosol concentrations in the air is a relevant endeavor due to potential health risks associated with exposure to such particles and in the understanding of their role in climate. In this context, the atmospheric concentrations of bacteria were measured from January 2018 to May 2020 at Saclay, France. The aim of the study was to understand the seasonality, the daily variability, and to identify the geographical origin of airborne bacteria.

PUB11-Dependent Ubiquitination of the Phospholipid Flippase ALA10 Modifies ALA10 Localization and Affects the Pool of Linolenic Phosphatidylcholine.

Biogenesis of photosynthetic membranes depends on galactolipid synthesis, which relies on several cell compartments, notably the endoplasmic reticulum (ER) and the chloroplast envelope. Galactolipid synthesis involves lipid trafficking between both membrane compartments. In , ALA10, a phospholipid flippase of the P type-ATPase family, counteracts the limitation of monogalactosyldiacylglycerol (MGDG) production and has a positive effect on leaf development.

Substantial brown carbon emissions from wintertime residential wood burning over France.

Brown carbon (BrC) is known to absorb light at subvisible wavelengths but its optical properties and sources are still poorly documented, leading to large uncertainties in climate studies. Here, we show its major wintertime contribution to total aerosol absorption at 370 nm (18-42%) at 9 different French sites. Moreover, an excellent correlation with levoglucosan (r = 0.

Wood burning: A major source of Volatile Organic Compounds during wintertime in the Paris region.

Wood burning is widely used for domestic heating and has been identified as a ubiquitous pollution source in urban areas, especially during cold months. The present study is based on a three and a half winter months field campaign in the Paris region measuring Volatile Organic Compounds (VOCs) by Proton Transfer Reaction Mass Spectrometry (PTR-MS) in addition to Black Carbon (BC). Several VOCs were identified as strongly wood burning-influenced (e.

A methodology for the characterization of portable sensors for air quality measure with the goal of deployment in citizen science.

The field of small air quality sensors is of growing interest within the scientific community, especially because this new technology is liable to improve air pollutant monitoring as well as be used for personal exposure quantification. Amongst the myriad existing devices, the performances are highly variable; this is why the sensors must be rigorously assessed before deployment, according to the intended use. This study is included in the Polluscope project; its purpose is to quantify personal exposure to air pollutants by using portable sensors.

Unveiling membrane thermoregulation strategies in marine picocyanobacteria.

The wide latitudinal distribution of marine Synechococcus cyanobacteria partly relies on the differentiation of lineages adapted to distinct thermal environments. Membranes are highly thermosensitive cell components, and the ability to modulate their fluidity can be critical for the fitness of an ecotype in a particular thermal niche. We compared the thermophysiology of Synechococcus strains representative of major temperature ecotypes in the field.

Measurement of Lipid Transport in Mitochondria by the MTL Complex.

Membrane biogenesis requires an extensive traffic of lipids between different cell compartments. Two main pathways, the vesicular and non-vesicular pathways, are involved in such a process. Whereas the mechanisms involved in vesicular trafficking are well understood, fewer is known about non-vesicular lipid trafficking, particularly in plants.

Quantitative Assessment of the Chloroplast Lipidome.

In plants and algae, photosynthetic membranes have a unique lipid composition. They differ from all other cellular membranes by their very low amount of phospholipids, besides some phosphatidylglycerol (PG), and high proportion of glycolipids. These glycolipids are the uncharged galactolipids, i.