scispace - formally typeset
Search or ask a question
Author

Manon Guille-Collignon

Bio: Manon Guille-Collignon is an academic researcher from École Normale Supérieure. The author has contributed to research in topics: Photosynthesis & Total internal reflection fluorescence microscope. The author has an hindex of 12, co-authored 27 publications receiving 364 citations. Previous affiliations of Manon Guille-Collignon include University of Paris & Centre national de la recherche scientifique.

Papers
More filters
Journal ArticleDOI
TL;DR: Quinones are dual compounds able to extract photosynthetic electrons from living organisms but with long-term poisoning effects.
Abstract: Plants, algae, and some bacteria convert solar energy into chemical energy by using photosynthesis In light of the current energy environment, many research strategies try to benefit from photosynthesis in order to generate usable photobioelectricity Among all the strategies developed for transferring electrons from the photosynthetic chain to an outer collecting electrode, we recently implemented a method on a preparative scale (high surface electrode) based on a Chlamydomonas reinhardtii green algae suspension in the presence of exogenous quinones as redox mediators While giving rise to an interesting performance (10-60 μA cm-2) in the course of one hour, this device appears to cause a slow decrease of the recorded photocurrent In this paper, we wish to analyze and understand this gradual fall in performance in order to limit this issue in future applications We thus first show that this kind of degradation could be related to over-irradiation conditions or side-effects of quinones depending on experimental conditions We therefore built an empirical model involving a kinetic quenching induced by incubation with quinones, which is globally consistent with the experimental data provided by fluorescence measurements achieved after dark incubation of algae in the presence of quinones

49 citations

Journal ArticleDOI
TL;DR: Interestingly, these results demonstrate that the presence of an aminoalkyl chain in the ferrocifen structure may confer a unique behavior toward both cell lines, in comparison with the two other compounds that lack this feature.
Abstract: Ferrocifens are an original class of ferrocifen-type breast cancer drugs They possess anti-proliferative effects due to the association of the ferrocene moiety and the tamoxifen skeleton In this work, fluorescence measurements indicated the production of reactive oxygen species (ROS) if hormone-dependent or -independent breast cancer cells were incubated with three hit ferrocifen compounds Additionally, amperometry at ultramicroelectrodes was carried out to identify and quantify ROS and reactive nitrogen species (RNS) under stress conditions Videomicroscopy was used to optimize the conditions employed for electrochemical investigations Amperometry was then performed on two cell lines pre-incubated with each of the three ferrocifens Interestingly, these results demonstrate that the presence of an aminoalkyl chain in the ferrocifen structure may confer a unique behavior toward both cell lines, in comparison with the two other compounds that lack this feature

48 citations

Journal ArticleDOI
TL;DR: It is shown that 2,6-dimethyl-p-benzoquinone (DMBQ) can be used as an electron mediator to assess the efficiency of mutations designed to engineer a novel electron donation pathway downstream of the primary electron acceptor QA of Photosystem (PS) II in the green alga Chlamydomonas reinhardtii.
Abstract: Strategies to harness photosynthesis from living organisms to generate electrical power have long been considered, yet efficiency remains low. Here, we aimed to reroute photosynthetic electron flow in photosynthetic organisms without compromising their phototrophic properties. We show that 2,6-dimethyl-p-benzoquinone (DMBQ) can be used as an electron mediator to assess the efficiency of mutations designed to engineer a novel electron donation pathway downstream of the primary electron acceptor QA of Photosystem (PS) II in the green alga Chlamydomonas reinhardtii. Through the use of structural prediction studies and a screen of site-directed PSII mutants we show that modifying the environment of the QA site increases the reduction rate of DMBQ. Truncating the C-terminus of the PsbT subunit protruding in the stroma provides evidence that shortening the distance between QA and DMBQ leads to sustained electron transfer to DMBQ, as confirmed by chronoamperometry, consistent with a bypass of the natural QA°− to QB pathway.

37 citations

Journal ArticleDOI
TL;DR: In this article, the electrochemical detection of nitric oxide (NO ) and peroxynitrite anion (ONOO − ) was investigated at Pt-black electrodes in microchannels.

36 citations

Journal ArticleDOI
TL;DR: Fluorescent False Neurotransmitter 102 (FFN102), a synthesized analogue of biogenic neurotransmitters, was demonstrated to show both pH-dependent fluorescence and electroactivity, which opens new possibilities in the investigation of exocytotic mechanisms.
Abstract: In this work, Fluorescent False Neurotransmitter 102 (FFN102), a synthesized analogue of biogenic neurotransmitters, was demonstrated to show both pH-dependent fluorescence and electroactivity. To study secretory behaviors at the single-vesicle level, FFN102 was employed as a new fluorescent/electroactive dual probe in a coupled technique (amperometry and total internal reflection fluorescence microscopy (TIRFM)). We used N13 cells, a stable clone of BON cells, to specifically accumulate FFN102 into their secretory vesicles, and then optical and electrochemical measurements of vesicular exocytosis were experimentally achieved by using indium tin oxide (ITO) transparent electrodes. Upon stimulation, FFN102 started to diffuse out from the acidic intravesicular microenvironment to the neutral extracellular space, leading to fluorescent emissions and to the electrochemical oxidation signals that were simultaneously collected from the ITO electrode surface. The correlation of fluorescence and amperometric signals resulting from the FFN102 probe allows real-time monitoring of single exocytotic events with both high spatial and temporal resolution. This work opens new possibilities in the investigation of exocytotic mechanisms.

33 citations


Cited by
More filters
Journal ArticleDOI
TL;DR: California has significantly reduced building energy demand through a series of progressive appliance and building standards that promote energy efficiency, which mean that California has among the lowest per capita electricity consumption rates in the nation.
Abstract: Goals Reduce greenhouse gas emissions to 1990 levels by 2020. All new residential buildings meet zero-­‐net-­‐energy (ZNE) goals by 2020, all new commercial buildings by 2030. Why it is Important Combustion of fossil fuels to power vehicles and buildings is the largest source of greenhouse gas emissions in the state. Energy use in residential and commercial buildings and the industrial sector is the second largest source of greenhouse gas (GHG) emissions in California. California has significantly reduced building energy demand through a series of progressive appliance and building standards that promote energy efficiency. These standards, combined with the state's mild climate, mean that California has among the lowest per capita electricity consumption rates of any state in the nation. In 2011, California had the fifth lowest per capita energy demand of any state. 1 Recent Trends Energy consumption occurs in all sectors of state's economy. In California, the transportation sector accounts for the highest share of the state's energy consumption. This demand is met, primarily, through the combustion of fossil fuels to power passenger cars and trucks. Consumption in the industrial, commercial, and industrial sectors is primarily accounted for by electricity and natural gas consumption. 1 Electricity use per capita in California is well below the national average 2 , owing to the state's appliance and building energy efficiency standards and mild climate. Even as the state's population has continued to grow, per capita electricity use has remained steady, while the national average has increased slightly. When comparing per capita energy consumption by sector, it is clear that California's energy efficiency efforts have been most successful in the building sector.

524 citations

Journal ArticleDOI
TL;DR: It is shown here the different antitumoral approaches offered by ferrocifen derivatives, originally simple derivatives of tamoxifen, which over the course of their development have proved to possess remarkable structural and mechanistic diversity.
Abstract: Despite current developments in therapeutics focusing on biotechnologically-oriented species, the unflagging utility of small molecules or peptides in medicine is still producing strong results. In 2014 for example, of the 41 new medicines authorized for sale, 33 belonged to the category of small molecules, while in 2013 they represented 24 of 27, according to the FDA. This can be explained as the result of recent forays into new or long-neglected areas of chemistry. Medicinal organometallic chemistry can provide us with an antimalarial against resistant parasitic strains, as attested by the phase II clinical development of ferroquine, with a new framework for conceptual advances based on three-dimensional space-filling, and with redox or indeed catalytic intracellular properties. In this context, bioferrocene species with antiproliferative potential have for several years been the subject of sustained effort, based on some initial successes and on the nature of ferrocene as a stable aromatic, with low toxicity, low cost, and possessing reversible redox properties. We show here the different antitumoral approaches offered by ferrocifen derivatives, originally simple derivatives of tamoxifen, which over the course of their development have proved to possess remarkable structural and mechanistic diversity. These entities act via various targets, some of which have been identified, that are triggered according to the concentration of the products. They also act according to the nature of the cancer cells and their functionality, by mechanistic pathways that can operate either synergistically or not, in successive, concomitant or sequential ways, depending for example on newly identified signaling pathways inducing senescence or apoptosis. Here we present a first attempt to rationalize the behavior of these entities with various anticancer targets.

422 citations

Journal ArticleDOI
TL;DR: The existing anatomical and functional evidence of local interactions between astrocytes and synapses is reviewed, and how it underlies a role for astroCytes in the computation of synaptic information is reviewed.
Abstract: Astrocytes intimately interact with synapses, both morphologically and, as evidenced in the past 20 years, at the functional level. Ultrathin astrocytic processes contact and sometimes enwrap the synaptic elements, sense synaptic transmission and shape or alter the synaptic signal by releasing signalling molecules. Yet, the consequences of such interactions in terms of information processing in the brain remain very elusive. This is largely due to two major constraints: (i) the exquisitely complex, dynamic and ultrathin nature of distal astrocytic processes that renders their investigation highly challenging and (ii) our lack of understanding of how information is encoded by local and global fluctuations of intracellular calcium concentrations in astrocytes. Here, we will review the existing anatomical and functional evidence of local interactions between astrocytes and synapses, and how it underlies a role for astrocytes in the computation of synaptic information.This article is part of the themed issue 'Integrating Hebbian and homeostatic plasticity'.

157 citations

Journal ArticleDOI
TL;DR: The development of platinized carbon nanoelectrodes with well-characterized geometry are reported and used as scanning electrochemical microscopy (SECM) tips to measure ROS and RNS inside noncancerous and metastatic human breast cells to elucidate the chemical origins and production rates of ROS/RNS in nontransformed and metastatics human Breast cells.
Abstract: The production of reactive oxygen and nitrogen species (ROS and RNS) in human cells is implicated in various diseases, including cancer. Micrometer-sized electrodes coated with Pt black and platinized Pt nanoelectrodes have previously been used for the detection of primary ROS and RNS in biological systems. In this Article, we report the development of platinized carbon nanoelectrodes with well-characterized geometry and use them as scanning electrochemical microscopy (SECM) tips to measure ROS and RNS inside noncancerous and metastatic human breast cells. By performing time-dependent quantitative amperometric measurements at different potentials, the relative concentrations of four key ROS/RNS in the cell cytoplasm and their dynamics were determined and used to elucidate the chemical origins and production rates of ROS/RNS in nontransformed and metastatic human breast cells.

128 citations