[Ag(IPr)(bpy)][PF6]: brightness and darkness playing with aggregation induced phosphorescence for light-emitting electrochemical cells.

Heteroleptic silver(I) complexes have recently started to attract attention in thin-film lighting technologies as an alternative to copper(I) analogues due to the lack of flattening distortion upon excitation. However, the interpretation of their photophysical behavior is challenging going from traditional fluorescence/phosphorescence to a temperature-dependent dual emission mechanism and ligand-lock assisted thermally activated delayed fluorescence. Herein, we unveil the photoluminescence behavior of a three-coordinated Ag(I) complex with the N-heterocyclic carbene (NHC) ligand and 2,2'-bipyridine (bpy) as the N^N ligand. In contrast to its low-emissive Cu(I) complex structural analogues, a strong greenish emission was attributed to the presence of aggregates formed by π-π intermolecular interactions as revealed by the X-ray structure and aggregation induced emission (AIE) studies in solution. In addition, the temperature-dependent time-resolved spectroscopic and computational studies demonstrated that the emission mechanism is related to a phosphorescence emission mechanism of two very close lying (ΔE = 0.08 eV) excited triplet states, exhibiting a similar delocalized nature over the bipyridine ligands. Unfortunately, this favourable AIE is lost upon forming homogeneous thin films suitable for lighting devices. Though the films showed very poor emission, the electrochemical stability under device operation conditions is remarkable compared to the prior-art, highlighting the potential of [Ag(NHC)(N^N)][X] complexes in thin-film lighting.

Blue-Light Induced Iron-Catalyzed Synthesis of γ,δ-Unsaturated Ketones.

A visible-light-induced iron-catalyzed α-alkylation of ketones with allylic and propargylic alcohols as pro-electrophiles is reported. The diaminocyclopentadienone iron tricarbonyl complex plays a dual role by harvesting light and facilitating dehydrogenation and reduction steps without the help of any exogenous photosensitizer. γ,δ-Unsaturated ketones can now be accessed through this borrowing hydrogen methodology at room temperature. Mechanistic investigations revealed that the steric hindrance on the δ-position of either the dienone or ene-ynone intermediate is the key feature to prevent or decrease the competitive 1,6-reduction (and consequently the formation of the saturated ketone) and to favor the synthesis of a set of non-conjugated enones and ynones.

First whole genome assembly and annotation of a European common bean cultivar using PacBio HiFi and Iso-Seq data.

Common bean (Phaseolus vulgaris L.) is the most important grain legume for direct human consumption worldwide. Flageolet bean originates from France and presents typical organoleptic properties, including the remarkable feature of having small pale green colored seeds. Here, we report the whole-genome data, assembly and annotation of the flageolet bean accession 'Flavert'. High molecular weight DNA and RNA were extracted and subjected to long-read sequencing using PacBio Sequel II platform. The genome consisted of 566,238,753 bp assembled in 13 molecules, including 11 chromosomes plus the mitochondrial and chloroplastic genomes. Annotation predicted 29,549 protein coding genes and 6,958 non-coding RNA. This high-quality genome (99.2% BUSCO completeness) represents a valuable data set for further genomic and genetic studies on common bean and more generally on legumes. To our knowledge, this is the first whole-genome sequence of a common bean accession originating from Europe.

Mass spectrometric characterization of the seco acid formed by cleavage of the macrolide ring of the algal metabolite goniodomin A.

Goniodomin A (GDA) is a polyketide macrolide produced by multiple species of the marine dinoflagellate genus Alexandrium. GDA is unusual in that it undergoes cleavage of the ester linkage under mild conditions to give mixtures of seco acids (GDA-sa). Ring-opening occurs even in pure water although the rate of cleavage accelerates with increasing pH. The seco acids exist as a dynamic mixture of structural and stereo isomers which is only partially separable by chromatography. Freshly prepared seco acids show only end absorption in the UV spectrum but a gradual bathochromic change occurs, which is consistent with formation of α,ß-unsaturated ketones. Use of NMR and crystallography is precluded for structure elucidation. Nevertheless, structural assignments can be made by mass spectrometric techniques. Retro-Diels-Alder fragmentation has been of value for independently characterizing the head and tail regions of the seco acids. The chemical transformations of GDA revealed in the current studies help clarify observations made on laboratory cultures and in the natural environment. GDA has been found to reside mainly within the algal cells while the seco acids are mainly external with the transformation of GDA to the seco acids occurring largely outside the cells. This relationship, plus the fact that GDA is short-lived in growth medium whereas GDA-sa is long-lived, suggests that the toxicological properties of GDA-sa in its natural environment are more important for the survival of the Alexandrium spp. than those of GDA. The structural similarity of GDA-sa to that of monensin is noted. Monensin has strong antimicrobial properties, attributed to its ability to transport sodium ions across cell membranes. We propose that toxic properties of GDA may primarily be due to the ability of GDA-sa to mediate metal ion transport across cell membranes of predator organisms.

Chromatin dynamics associated with seed desiccation tolerance/sensitivity at early germination in Medicago truncatula.

Desiccation tolerance (DT) has contributed greatly to the adaptation of land plants to severe water-deficient conditions. DT is mostly observed in reproductive parts in flowering plants such as seeds. The seed DT is lost at early post germination stage but is temporally re-inducible in 1 mm radicles during the so-called DT window following a PEG treatment before being permanently silenced in 5 mm radicles of germinating seeds. The molecular mechanisms that activate/reactivate/silence DT in developing and germinating seeds have not yet been elucidated. Here, we analyzed chromatin dynamics related to re-inducibility of DT before and after the DT window at early germination in Medicago truncatula radicles to determine if DT-associated genes were transcriptionally regulated at the chromatin levels. Comparative transcriptome analysis of these radicles identified 948 genes as DT re-induction-related genes, positively correlated with DT re-induction. ATAC-Seq analyses revealed that the chromatin state of genomic regions containing these genes was clearly modulated by PEG treatment and affected by growth stages with opened chromatin in 1 mm radicles with PEG (R1P); intermediate openness in 1 mm radicles without PEG (R1); and condensed chromatin in 5 mm radicles without PEG (R5). In contrast, we also showed that the 103 genes negatively correlated with the re-induction of DT did not show any transcriptional regulation at the chromatin level. Additionally, ChIP-Seq analyses for repressive marks H2AK119ub and H3K27me3 detected a prominent signal of H3K27me3 on the DT re-induction-related gene sequences at R5 but not in R1 and R1P. Moreover, no clear H2AK119ub marks was observed on the DT re-induction-related gene sequences at both developmental radicle stages, suggesting that silencing of DT process after germination will be mainly due to H3K27me3 marks by the action of the PRC2 complex, without involvement of PRC1 complex. The dynamic of chromatin changes associated with H3K27me3 were also confirmed on seed-specific genes encoding potential DT-related proteins such as LEAs, oleosins and transcriptional factors. However, several transcriptional factors did not show a clear link between their decrease of chromatin openness and H3K27me3 levels, suggesting that their accessibility may also be regulated by additional factors, such as other histone modifications. Finally, in order to make these comprehensive genome-wide analyses of transcript and chromatin dynamics useful to the scientific community working on early germination and DT, we generated a dedicated genome browser containing all these data and publicly available at https://iris.angers.inrae.fr/mtseedepiatlas/jbrowse/?data=Mtruncatula.

Blue-Light-Induced Iron-Catalyzed α-Alkylation of Ketones.

We report a visible-light-induced iron-catalyzed α-alkylation of ketones. The photocatalytic system is based on the single diaminocyclopentadienone iron tricarbonyl complex. Two catalytic intermediates of this complex are able to harvest light, allowing the synthesis of substituted aromatic and aliphatic ketones at room temperature using the borrowing hydrogen strategy in the presence of various substituted primary alcohols as alkylating reagents. Preliminary mechanistic studies unveil the role of light for both the dehydrogenation and reduction step.

Characterization of toxin-producing strains of Dinophysis spp. (Dinophyceae) isolated from French coastal waters, with a particular focus on the D. acuminata-complex.

Dinoflagellates of the genus Dinophysis are the most prominent producers of Diarrhetic Shellfish Poisoning (DSP) toxins which have an impact on public health and on marine aquaculture worldwide. In particular, Dinophysis acuminata has been reported as the major DSP agent in Western Europe. Still, its contribution to DSP events in the regions of the English Channel and the Atlantic coast of France, and the role of the others species of the Dinophysis community in these areas are not as clear. In addition, species identification within the D. acuminata complex has proven difficult due to their highly similar morphological features. In the present study, 30 clonal strains of the dominant Dinophysis species have been isolated from French coasts including the English Channel (3 sites), the Atlantic Ocean (11 sites) and the Mediterranean Sea (6 sites). Morphologically, strains were identified as three species: D. acuta, D. caudata, D. tripos, as well as the D. acuminata-complex. Sequences of the ITS and LSU rDNA regions confirmed these identifications and revealed no genetic difference within the D. acuminata-complex. Using the mitochondrial gene cox1, two groups of strains differing by only one substitution were found in the D. acuminata-complex, but SEM analysis of various strains showed a large range of morphological variations. Based on geographical origin and morphology, strains of the subclade A were ascribed to 'D. acuminata' while those of the subclade B were ascribed to 'D. sacculus'. Nevertheless, the distinction into two separate species remains questionable and was not supported by our genetic data. The considerable variations observed in cultured strains suggest that physiological factors might influence cell contour and bias identification. Analyses of Dinophysis cultures from French coastal waters using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) revealed species-conserved toxin profiles for D. acuta (dinophysistoxin 2 (DTX2), okadaic acid (OA), pectenotoxin 2 (PTX2)), D. caudata (PTX2) and D. tripos (PTX2), irrespective of geographical origin (Atlantic Ocean or Mediterranean Sea). Within the D. acuminata-complex, two different toxin profiles were observed: the strains of 'D. acuminata' (subclade A) from the English Channel and the Atlantic Ocean contained only OA while strains of 'D. sacculus' (subclade B) from Mediterranean Sea/Atlantic Ocean contained PTX2 as the dominant toxin, with OA and C9-esters also being present, albeit in lower proportions. The same difference in toxin profiles between 'D. sacculus' and 'D. acuminata' was reported in several studies from Galicia (NW- Spain). This difference in toxin profiles has consequences in terms of public health, and consequently for monitoring programs. While toxin profile could appear as a reliable feature separating 'D. acuminata' from 'D. sacculus' on both French and Spanish coasts, this does not seem consistent with observations on a broader geographical scale for the D. acuminata complex, possibly due to the frequent lack of genetic characterization.

Effect of a short-term salinity stress on the growth, biovolume, toxins, osmolytes and metabolite profiles on three strains of the Dinophysis acuminata-complex (Dinophysis cf. sacculus).

Dinophysis is the main dinoflagellate genus responsible for diarrheic shellfish poisoning (DSP) in human consumers of filter feeding bivalves contaminated with lipophilic diarrheic toxins. Species of this genus have a worldwide distribution driven by environmental conditions (temperature, irradiance, salinity, nutrients etc.), and these factors are sensitive to climate change. The D. acuminata-complex may contain several species, including D. sacculus. The latter has been found in estuaries and semi-enclosed areas, water bodies subjected to quick salinity variations and its natural repartition suggests some tolerance to salinity changes. However, the response of strains of D. acuminata-complex (D. cf. sacculus) subjected to salinity stress and the underlying mechanisms have never been studied in the laboratory. Here, a 24 h hypoosmotic (25) and hyperosmotic (42) stress was performed in vitro in a metabolomic study carried out with three cultivated strains of D. cf. sacculus isolated from the French Atlantic and Mediterranean coasts. Growth rate, biovolume and osmolyte (proline, glycine betaine and dimethylsulfoniopropionate (DMSP)) and toxin contents were measured. Osmolyte contents were higher at the highest salinity, but only a significant increase in glycine betaine was observed between the control (35) and the hyperosmotic treatment. Metabolomics revealed significant and strain-dependent differences in metabolite profiles for different salinities. These results, as well as the absence of effects on growth rate, biovolume, okadaic acid (OA) and pectenotoxin (PTXs) cellular contents, suggest that the D. cf. sacculus strains studied are highly tolerant to salinity variations.

Towards rainbow photo/electro-luminescence in copper(i) complexes with the versatile bridged bis-pyridyl ancillary ligand.

The synthesis and characterization of a family of copper(i) complexes bearing a bridged bis-pyridyl ancillary ligand is reported, highlighting how the bridge nature impacts the photo- and electro-luminescent behaviours within the family. In particular, the phosphonium bridge led to copper(i) complexes featuring good electrochemical stability and high ionic conductivity, as well as a stark blue-to-orange luminescence shift compared to the others. This resulted in high performance light-emitting electrochemical cells reaching stabilities of 10 mJ at ca. 40 cd m-2 that are one order of magnitude higher than those of the other complexes. Overall, this work sheds light onto the crucial role of the bridge nature of the bis-pyridyl ancillary ligand on the photophysical features, film forming and, in turn, on the final device performances.

Phosphine-Free Ruthenium Complex-Catalyzed Synthesis of Mono- or Dialkylated Acyl Hydrazides via the Borrowing Hydrogen Strategy.

Herein, we report a diaminocyclopentadienone ruthenium tricarbonyl complex-catalyzed synthesis of mono- or dialkylated acyl hydrazide compounds using the borrowing hydrogen strategy in the presence of various substituted primary and secondary alcohols as alkylating reagents. Deuterium labeling experiments confirm that the alcohols were the hydride source in this cascade process. Density functional theory (DFT) calculations unveil the origin and the threshold between the mono- and dialkylation.

Palladium-Catalyzed Domino Heck/Sulfination: Synthesis of Sulfonylated Hetero- and Carbocyclic Scaffolds Using DABCO-Bis(sulfur dioxide).

The synthesis of a broad variety of hetero- and carbocyclic scaffolds via a Pd-catalyzed domino Heck/SO2 insertion reaction is reported. This reaction utilizes DABSO, a safe and easy-to-handle alternative to SO2 gas. The reaction proceeds through a sulfinate intermediate, which can act as a lynchpin for the in situ generation of sulfones, sulfonamides, and sulfonyl fluorides. Good yields and scalability are demonstrated.

A phosphine-free iron complex-catalyzed synthesis of cycloalkanes via the borrowing hydrogen strategy.

Herein we report a diaminocyclopentadienone iron tricarbonyl complex catalyzed synthesis of substituted cyclopentane, cyclohexane and cycloheptane compounds using the borrowing hydrogen strategy in the presence of various substituted primary and secondary 1,n diols as alkylating reagents. Deuterium labeling experiments confirm that the diols were the hydride source in this cascade process.

Solving the challenging synthesis of highly cytotoxic silver complexes bearing sterically hindered NHC ligands with mechanochemistry.

The use of ball-mills enabled the straightforward synthesis of a variety of silver(i) complexes featuring challenging NHC ligands. Sterically hindered including electron-poor or with very low solubility imidazolium salts were ground with silver(i) oxide to furnish heteroleptic or homoleptic complexes in high yields and short reaction times. The synthesis of heteroleptic bis-NHC silver(i) complexes was also performed for the first time in a ball mill. The efficiency and rapidity of the mechanochemical approach enabled the generation of a library of unprecedented NHC silver complexes, whose cytotoxicity on the HCT116 colorectal cancer cell line was evaluated providing a rare example of medicinal mechanochemistry. The cationic silver complexes were found to be more potent than the neutral analogues, with IC50 values down to 21 nM and 256 times more potent than cisplatin.

Cultures of Dinophysis sacculus, D. acuminata and pectenotoxin 2 affect gametes and fertilization success of the Pacific oyster, Crassostrea gigas.

Harmful algal blooms (HABs) of toxic species of the dinoflagellate genus Dinophysis are a threat to human health as they are mainly responsible for diarrheic shellfish poisoning (DSP) in the consumers of contaminated shellfish. Such contamination leads to shellfish farm closures causing major economic and social issues. The direct effects of numerous HAB species have been demonstrated on adult bivalves, whereas the effects on critical early life stages remain relatively unexplored. The present study aimed to determine the in vitro effects of either cultivated strains of D. sacculus and D. acuminata isolated from France or their associated toxins (i.e. okadaic acid (OA) and pectenotoxin 2 (PTX2)) on the quality of the gametes of the Pacific oyster Crassostrea gigas. This was performed by assessing the ROS production and viability of the gametes using flow cytometry, and fertilization success using microscopic counts. Oocytes were more affected than spermatozoa and their mortality and ROS production increased in the presence of D. sacculus and PTX2, respectively. A decrease in fertilization success was observed at concentrations as low as 0.5 cell mL-1 of Dinophysis spp. and 5 nM of PTX2, whereas no effect of OA could be observed. The effect on fertilization success was higher when both gamete types were concomitantly exposed compared to separate exposures, suggesting a synergistic effect. Our results also suggest that the effects could be due to cell-to-cell contact. These results highlight a potential effect of Dinophysis spp. and PTX2 on reproduction and recruitment of the Pacific oyster.

Risks and contraindications of medical compression treatment - A critical reappraisal. An international consensus statement.

OBJECTIVES: Medical compression therapy is used for non-invasive treatment of venous and lymphatic diseases. Medical compression therapy-associated adverse events and contraindications have been reported, although some contraindications are theoretically based. This consensus statement provides recommendations on medical compression therapy risks and contraindications. METHODS: A systematic literature search of medical compression therapy publications reporting adverse events up until November 2017 was performed. A consensus panel comprising 15 international experts critically reviewed the publications and formulated the recommendations. RESULTS: Sixty-two publications reporting medical compression therapy adverse events were identified. The consensus panel issued 21 recommendations on medical compression therapy contraindications and adverse event risk mitigation, in addition to reviewing medical compression therapy use in borderline indications. The most frequently reported non-severe medical compression therapy-associated adverse events included skin irritation, discomfort and pain. Very rare but severe adverse events, including soft tissue and nerve injury, were also identified. CONCLUSION: This consensus statement summarises published medical compression therapy-associated adverse events and contraindications, and provides guidance on medical compression therapy. Severe medical compression therapy-associated adverse events are very rarely encountered if compression is used correctly and contraindications are considered.

Aminomethylation of Oxabenzonorbornadienes via the Merger of Photoredox and Nickel Catalysis.

The first aminomethylation of oxabenzonorbornadienes using dual photoredox/nickel catalysis has been disclosed. This cascade reaction allowed the preparation of the cis-aminomethyl dihydronaphthalenols without any prefunctionalization or any use of nucleophilic organometallic species. The control of the regio- and stereoselectivity might be explained by a sequence involving insertion of nickel(0) into the C-O bond followed by the formation of a π-allyl intermediate.

Artificial iron hydrogenase made by covalent grafting of Knölker's complex into xylanase: Application in asymmetric hydrogenation of an aryl ketone in water.

We report a new artificial hydrogenase made by covalent anchoring of the iron Knölker's complex to a xylanase S212C variant. This artificial metalloenzyme was found to be able to catalyze efficiently the transfer hydrogenation of the benchmark substrate trifluoroacetophenone by sodium formate in water, yielding the corresponding secondary alcohol as a racemic. The reaction proceeded more than threefold faster with the XlnS212CK biohybrid than with the Knölker's complex alone. In addition, efficient conversion of trifluoroacetophenone to its corresponding alcohol was reached within 60 H with XlnS212CK, whereas a ≈2.5-fold lower conversion was observed with Knölker's complex alone as catalyst. Moreover, the data were rationalized with a computational strategy suggesting the key factors of the selectivity. These results suggested that the Knölker's complex was most likely flexible and could experience free rotational reorientation within the active-site pocket of Xln A, allowing it to access the subsite pocket populated by trifluoroacetophenone.

Iron-Catalyzed α-Alkylation of Ketones with Secondary Alcohols: Access to ß-Disubstituted Carbonyl Compounds.

An iron-catalyzed borrowing hydrogen strategy has been applied in the synthesis of ß-branched carbonyl compounds. Various secondary benzylic and aliphatic alcohols have been used as alkylating reagents under mild reaction conditions. The ketones have been isolated in good to excellent yield. Deuterium labeling experiments provide evidence that the alcohol is the hydride source in this reaction and that no reversible step or hydrogen/deuterium scrambling takes place during the process.

Combined Effects of Temperature, Irradiance, and pH on Teleaulax amphioxeia (Cryptophyceae) Physiology and Feeding Ratio For Its Predator Mesodinium rubrum (Ciliophora)1.

The cryptophyte Teleaulax amphioxeia is a source of plastids for the ciliate Mesodinium rubrum and both organisms are members of the trophic chain of several species of Dinophysis. It is important to better understand the ecology of organisms at the first trophic levels before assessing the impact of principal factors of global change on Dinophysis spp. Therefore, combined effects of temperature, irradiance, and pH on growth rate, photosynthetic activity, and pigment content of a temperate strain of T. amphioxeia were studied using a full factorial design (central composite design 23 *) in 17 individually controlled bioreactors. The derived model predicted an optimal growth rate of T. amphioxeia at a light intensity of 400 µmol photons · m-2 · s-1 , more acidic pH (7.6) than the current average and a temperature of 17.6°C. An interaction between temperature and irradiance on growth was also found, while pH did not have any significant effect. Subsequently, to investigate potential impacts of prey quality and quantity on the physiology of the predator, M. rubrum was fed two separate prey: predator ratios with cultures of T. amphioxeia previously acclimated at two different light intensities (100 and 400 µmol photons · m-2 s-1 ). M. rubrum growth appeared to be significantly dependent on prey quantity while effect of prey quality was not observed. This multi-parametric study indicated a high potential for a significant increase of T. amphioxeia in future climate conditions but to what extent this would lead to increased occurrences of Mesodinium spp. and Dinophysis spp. should be further investigated.