Ethical challenges at the science-policy interface: an ethical risk assessment and proposition of an ethical infrastructure

Developing an interface between knowledge holders, stakeholders and decision makers on biodiversity issues, just as any science-policy interface, will face many challenges. In the crucial endeavour to tackle all those challenges, determining an ethical course of actions will be essential to the prestige and credibility of such an interface. The paper identifies and assesses potential ethical risks that may arise in interactions between science, society and policy and uses the Network of Knowledge (NoK) process as an example to show how an ethical infrastructure could be developed for minimizing the ethical risks and their potential consequences. Indeed, when various actors from different spheres (politics, academia, lobbyism, media, etc.) are called upon to interact within one process as complex as the NoK, the integrity and credibility of the latter are at high risk of being compromised if the ethical risks are not adequately addressed. In order to limit those risks, which science-policy interfaces such as IPCC and IPBES have already encountered, we propose to set up an ethical governance infrastructure that will guide (and regulate) interactions among internal actors of the NoK (knowledge coordination body, secretariat, expert working groups, etc.) as well as with external actors (requesters, stakeholders, etc.). A thorough evaluation of the interaction between the actors for every step of the process is carried out and potential ethical risks are identified. Suggestions as to how the risks can be handled and prevented are presented and integrated as part of an ethical infrastructure. The main objective of the paper is to address how a science-policy interface and the scientific community as a whole would benefit from implementing ethical measures and instruments to help prevent sensitive issues and undesired consequences undermining credibility and legitimacy.     

Structural insights and membrane binding properties of MGD1, the major galactolipid synthase in plants

Monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) are the major lipid components of photosynthetic membranes, and hence the most abundant lipids in the biosphere. They are essential for assembly and function of the photosynthetic apparatus. In Arabidopsis, the first step of galactolipid synthesis is catalyzed by MGDG synthase 1 (MGD1), which transfers a galactosyl residue from UDP‐galactose to diacylglycerol (DAG). MGD1 is a monotopic protein that is embedded in the inner envelope membrane of chloroplasts. Once produced, MGDG is transferred to the outer envelope membrane, where DGDG synthesis occurs, and to thylakoids. Here we present two crystal structures of MGD1: one unliganded and one complexed with UDP. MGD1 has a long and flexible region (approximately 50 amino acids) that is required for DAG binding. The structures reveal critical features of the MGD1 catalytic mechanism and its membrane binding mode, tested on biomimetic Langmuir monolayers, giving insights into chloroplast membrane biogenesis. The structural plasticity of MGD1, ensuring very rapid capture and utilization of DAG, and its interaction with anionic lipids, possibly driving the construction of lipoproteic clusters, are consistent with the role of this enzyme, not only in expansion of the inner envelope membrane, but also in supplying MGDG to the outer envelope and nascent thylakoid membranes.     

Effect of in vivo gamma-irradiation on the binding of wheat germ agglutinin on lymphocyte plasma membranes

Using quantitative fluorimetry with fluoresceinated wheat germ agglutinin, we have been able to investigate in vivo gamma radiation-induced damage at the outer membrane level of rat splenic lymphocytes, namely damage to the glucosidic moieties of membrane glycoproteins and glycolipids. This paper demonstrates that below an irradiation level of 1 gray (Gy), removal of sialic acid is the major feature leading to new exposed specific binding sites for wheat germ agglutinin, since this lectin is specific for sialic acid and N-acetyl-D-glucosamine. Our studies also suggest that above 1 Gy of irradiation more internal damage occurs, since we observed a striking decrease in wheat germ agglutinin binding sites.     

Microanalysis of plant mitochondrial protein synthesis products:

Summary A mitochondrial fraction obtained from 0.5 g of leaves was purified on a 0.75 ml Percoll gradient and used for an in vitro mitochondrial protein synthesis assay in the presence of [³⁵S] methionine. A set of 15 to 20 labeled polypeptides were revealed by autoradiography after sodium dodecylsulfate polyacrylamide gel electrophoresis. This could be applied at an early growth stage by using a few leaves from individual seedlings. It revealed the presence of variant mitochondrially translated polypeptides in green leaves of cytoplasmic male sterile lines from various cultivated plants of large economic importance: maize, wheat, sugar beet, tobacco and faba bean. This non-destructive microanalysis is thus of general use and opens new possibilities for rapid and large mass screening of mitochondrial parameters such as male sterility.     

Isosorbide dinitrate bioconversion by Beauveria strains: implication of glutathione transferase levels

Summary The level of glutathione S-transferase (GSH0ST) activity was determined in growing cultures and in washed resting cells of Beauveria strains with and without addition of isosorbide dinitrate (ISDN), by following the reaction with o-dinitrobenzene (o-DNB). The level of GSH-ST varied according to the pH changes of the medium and decreased during culture. The enzymatic activity measured with o-DNB did not correlate with ISDN bioconversion carried out either with B. sulfurescens or B. tenella. Immediately after starting incubation of the resting cells with ISDN, the level of GSH-ST activity initially increased, but declined afterwards, whereas the bioconversion process continued and reached 500 mg/l isosorbide 5-mononitrate. When 1-chloro-2,4-dinitrobenzene was used as a substrate for the evaluation of GSH-ST activity using B. tenella, a conjugation product having a UV absorption at 410 nm was formed.     

ROP18 is a rhoptry kinase controlling the intracellular proliferation of Toxoplasma gondii

Toxoplasma gondii is an obligate intracellular parasite for which the discharge of apical organelles named rhoptries is a key event in host cell invasion. Among rhoptry proteins, ROP2, which is the prototype of a large protein family, is translocated in the parasitophorous vacuole membrane during invasion. The ROP2 family members are related to protein-kinases, but only some of them are predicted to be catalytically active, and none of the latter has been characterized so far. We show here that ROP18, a member of the ROP2 family, is located in the rhoptries and re-localises at the parasitophorous vacuole membrane during invasion. We demonstrate that a recombinant ROP18 catalytic domain (amino acids 243-539) possesses a protein-kinase activity and phosphorylate parasitic substrates, especially a 70-kDa protein of tachyzoites. Furthermore, we show that overexpression of ROP18 in transgenic parasites causes a dramatic increase in intra-vacuolar parasite multiplication rate, which is correlated with kinase activity. Therefore, we demonstrate, to our knowledge for the first time, that rhoptries can discharge active protein-kinases upon host cell invasion, which can exert a long-lasting effect on intracellular parasite development and virulence.     

Inverted topology of the Toxoplasma gondii ROP5 rhoptry protein provides new insights into the association of the ROP2 protein family with the parasitophorous vacuole membrane

Toxoplasma gondii, as many intracellular parasites, is separated from the cytosol of its host cell by a parasitophorous vacuole membrane (PVM). This vacuole forms during host cell invasion and parasite apical organelles named rhoptries discharge proteins that associate with its membrane during this process. We report here the characterization of the rhoptry protein ROP5, which is a new member of the ROP2 family. Contrasting with what is known for other ROP2 family proteins, ROP5 is not processed during trafficking to rhoptries. We show here that ROP5 is secreted during invasion and associates with the PVM. Using differential permeabilization of infected cells, we have shown that ROP5 exposes its C-terminus towards the host cell cytoplasm, which corresponds to a reverse topology compared with ROP2 and ROP4. Taken together with recent modelling data suggesting that the C-terminal hydrophobic domain hitherto described as transmembrane may correspond to a hydrophobic helix buried in the catalytic domain of kinase-related proteins, these findings call for a reappraisal of the current view of ROP2 family proteins association with the PVM.