The changing culture of silviculture

Changing climates are altering the structural and functional components of forest ecosystems at an unprecedented rate. Simultaneously, we are seeing a diversification of public expectations on the broader sustainable use of forest resources beyond timber production. As a result, the science and art of silviculture needs to adapt to these changing realities. In this piece, we argue that silviculturists are gradually shifting from the application of empirically derived silvicultural scenarios to new sets of approaches, methods and practices, a process that calls for broadening our conception of silviculture as a scientific discipline. We propose a holistic view of silviculture revolving around three key themes: observe, anticipate and adapt. In observe, we present how recent advances in remote sensing now enable silviculturists to observe forest structural, compositional and functional attributes in near-real-time, which in turn facilitates the deployment of efficient, targeted silvicultural measures in practice that are adapted to rapidly changing constraints. In anticipate, we highlight the importance of developing state-of-the-art models designed to take into account the effects of changing environmental conditions on forest growth and dynamics. In adapt, we discuss the need to provide spatially explicit guidance for the implementation of adaptive silvicultural actions that are efficient, cost-effective and socially acceptable. We conclude by presenting key steps towards the development of new tools and practical knowledge that will ensure meeting societal demands in rapidly changing environmental conditions. We classify these actions into three main categories: reexamining existing silvicultural trials to identify key stand attributes associated with the resistance and resilience of forests to multiple stressors, developing technological workflows and infrastructures to allow for continuous forest inventory updating frameworks, and implementing bold, innovative silvicultural trials in consultation with the relevant communities where a range of adaptive silvicultural strategies are tested. In this holistic perspective, silviculture can be defined as the science of observing forest condition and anticipating its development to apply tending and regeneration treatments adapted to a multiplicity of desired outcomes in rapidly changing realities

Report from the 28th Meeting on Toxinology, “Toxins: What’s up, Doc?”, Organized by the French Society of Toxinology on 28–29 November 2022

International audienceThe French Society of Toxinology (SFET) organized its 28th annual meeting on 28–29 November 2022 (RT28). The central theme of this meeting was “Toxins: What’s up, Doc?”, emphasizing the latest findings on animal, bacterial, algal, plant and fungal toxins through sessions dedicated to deep learning, toxin tracking and toxinomic advances, shared by ca. 80 participants. The abstracts of the 10 invited and 11 selected lectures and 15 posters, along with the names of the Best Oral Communication and Best Poster awardees, are presented in this report

Report from the 28th Meeting on Toxinology, “Toxins: What’s up, Doc?”, Organized by the French Society of Toxinology on 28–29 November 2022

The French Society of Toxinology (SFET) organized its 28th annual meeting on 28–29 November 2022 (RT28). The central theme of this meeting was “Toxins: What’s up, Doc?”, emphasizing the latest findings on animal, bacterial, algal, plant and fungal toxins through sessions dedicated to deep learning, toxin tracking and toxinomic advances, shared by ca. 80 participants. The abstracts of the 10 invited and 11 selected lectures and 15 posters, along with the names of the Best Oral Communication and Best Poster awardees, are presented in this report

Report from the 28th Meeting on Toxinology, “Toxins: What’s up, Doc?”, Organized by the French Society of Toxinology on 28–29 November 2022

International audienceThe French Society of Toxinology (SFET) organized its 28th annual meeting on 28–29 November 2022 (RT28). The central theme of this meeting was “Toxins: What’s up, Doc?”, emphasizing the latest findings on animal, bacterial, algal, plant and fungal toxins through sessions dedicated to deep learning, toxin tracking and toxinomic advances, shared by ca. 80 participants. The abstracts of the 10 invited and 11 selected lectures and 15 posters, along with the names of the Best Oral Communication and Best Poster awardees, are presented in this report

Report from the 29th Meeting on Toxinology, “Toxins: From the Wild to the Lab”, Organized by the French Society of Toxinology on 30 November–1 December 2023

International audienceThe French Society of Toxinology (SFET), which celebrated its 30th anniversary this year, organized its 29th annual Meeting (RT29), shared by 87 participants, on 30 November–1 December 2023. The RT29 main theme, “Toxins: From the Wild to the Lab”, focused on research in the field of animal venoms and animal, bacterial, fungal, or plant toxins, from their discovery in nature to their study in the laboratory. The exploration of the functions of toxins, their structures, their molecular or cellular ligands, their mode of action, and their potential therapeutic applications were emphasized during oral communications and posters through three sessions, of which each was dedicated to a secondary theme. A fourth, “miscellaneous” session allowed participants to present recent out-of-theme works. The abstracts of nine invited and 15 selected lectures, those of 24 posters, and the names of the Best Oral Communication and Best Poster awardees, are presented in this report

Evaluation of Clostridium botulinum A5 neurotoxin actions in vivo and ex vivo at the mouse skeletal neuromuscular junction

International audienceClostridium botulinum neurotoxins (BoNTs), the most potent toxins known, are the cause of a worldwide lifethreatening disease in humans and animals known as botulism. This disease usually manifests as descending symmetrical flaccid paralysis of skeletal muscles together with autonomic dysfunction. BoNTs include a large family of zinc metalloproteases that can be immunologically distinguished by homologous antitoxins into seven primary serotypes, designated A to G. Additionally, for BoNT/A, at least 8 subtypes (/A1-/A8) have been identified from gene sequence analysis. In France, several cases of human botulism due to BoNT/A5, /A6 or /A7 have been reported, though BoNT/A1 and /A2 are the prevalent forms of type-A botulism. The characterization of the C. botulinum strains involved in two cases of BoNT/A5-poisoning revealed that they possess the gene encoding for BoNT/A5 identical to the one previously reported. In the present study, we produced the BoNT/A5 crude complex (3 x 107 LD50/mg) from the C. botulinum A5 strain 126.07 [1], and studied in vivo and ex vivo, in murine models, the skeletal neuromuscular block caused by BoNT/A5, at different times after a single local toxin injection into the hind-limbs. The results show that the duration and degree of paralysis depended on the dose of BoNT/A5 and on the mouse strain studied. The transgenic Thy-1-YFP-16 black C57BL6 mice [2] were more sensitive to the action of the toxin than Swiss mice, as revealed by the digit abduction score (DAS) assay and by compound muscle action potential (CMAP) recordings from the same mouse in vivo, at different times after toxin injection. functional and morphological ex vivo studies on muscles locally injected with BoNT/A5 in vivo reveal (a) the presence of axonal outgrowths (nodal and nerve terminal sprouts), (b) an extension of nicotinic acetylcholine receptor clusters, (c) a reduction of both muscle weight and muscle fiber cross sectional area, and (d) the prolonged atrophy of muscle fibers. Pre- and post-synaptic remodeling was completely abolished by an immune-purified rabbit polyclonal antibody directed against the BoNT/A1-Heavy chain (HcA1), when injected together with BoNT/A5. In conclusion, our results show that the actions of BoNT/A5 have many similarities to those of BoNT/A1 previously reported, although no direct comparison was performed in the present study. BoNT/A5 differed from BoNT/A1 by 5 identified amino acids in the Light chain domain (Lc) and by 32 amino acids in the Heavy chain domain (Hc). The fact that the antibody directed to the HcA1 completely prevented the lethal effect of BoNT/A5, as well as the block of the CMAP in vivo, and the morphological changes induced by the neurotoxin suggest that the antibody blocks the entry of BoNT/A5 into motor nerve terminals of the neuromuscular junction

3,4-Diaminopyridine antagonizes the block of muscle nicotinic acetylcholine receptor caused by cyclic imine toxins at isolated mouse diaphragm preparations

International audienceCyclic imine toxins (CiTXs) are a family of worldwide-distributed marine macrocyclic phycotoxins comprising different groups of lipophilic compounds: gymnodimines (GYMs), spirolides, pinnatoxins (PnTXs), pteriatoxins (PteTXs), portimines, prorocentrolides and spiroprorocentrimine. CiTXs and the acyl derivative products of shellfish metabolism contaminate and bioaccumulate in filter-feeding bivalves, edible mollusks and other marine invertebrates and thus, represent a risk for shellfish consumers and a menace for wildlife conservation. All CiTXs studied interact and block, with different affinities, embryonic (α12βγδ) and mature (α12βεδ) nicotinic acetylcholine receptors (nAChRs) expressed in skeletal muscles. 3,4-Diaminopyridine (3,4-DAP) is a well-known K+-channel blocker that prolongs the presynaptic action potential and indirectly enhances the entry of Ca2+ into nerve terminals and, thereby, increases quantal ACh release at the neuromuscular junction. 3,4-DAP is used effectively to treat muscular weakness in various human myasthenic syndromes. The aim of this work was to determine whether 3,4-DAP, which increases quantal ACh release, is able to reverse the action of CiTXs on skeletal muscle expressing α12βεδ nAChRs. The use of isolated mouse phrenic-nerve-hemi-diaphragm muscle preparations enabled monitoring nerve-evoked isometric muscle contraction in the presence of GYM-A, PnTX-A, PnTX-G and PteTX-A and, afterwards, the action of 3,4-DAP (10-100 μM) in the continuous presence of the respective CiTXs. The results show that 3,4-DAP improves neuromuscular function in a time- and concentration-dependent manner and, at the highest concentration used (100 μM), completely reverses the neuromuscular block caused by the CiTX studied. These results support the view that GYM-A, PnTX-A, PnTX-G and PteTX-A are competitive and reversible inhibitors of muscle-type α12βεδ nAChRs. In fact, CiTXs can be typified as competing with the binding of ACh (the natural ligand) to the nAChR. The ability of 3,4-DAP to antagonize the action of CiTXs is related to the increased release of ACh that is able to displace the respective CiTX from their nAChR binding sites