A new fluorescence-based approach for direct visualization of coat formation during sporulation in Bacillus cereus

Funding Information: The Ph.D. thesis of A.L. was funded by INRAE and the PACA Region and was partly supported by a grant of the MICA division and a Perdiguier grant of Avignon University. Part of this work was supported by the microscopy facilities of the Platform 3A, funded by the European Regional Development Fund, the French Ministry of Research, Higher Education and Innovation, the Provence-Alpes-Côte d’Azur region, the Departmental Council of Vaucluse and the Urban Community of Avignon. This work was also funded through grants PEst-OE/EQB/LA0004/2011 to AOH, by project LISBOA-01-0145-FEDER-007660 (“Microbiologia Molecular, Estrutural e Celular”) funded by FEDER funds through COMPETE2020 – “Programa Operacional Competitividade e Internacionalização”, and by project PPBI—Portuguese Platform of BioImaging (PPBI-POCI-01-0145-FEDER-022122) co-funded by national funds from OE—"Orçamento de Estado" and by European funds from FEDER—"Fundo Europeu de Desenvolvimento Regional". Work and Lattice SIM imaging in the R.C-L. lab was supported by funding from the European Research Council (ERC) under the Horizon 2020 research and innovation program (grant agreement No 772178, ERC Consolidator grant to R.C.-L.). Publisher Copyright: © 2023, Springer Nature Limited.The human pathogenic bacteria Bacillus cereus, Bacillus anthracis and the entomopathogenic Bacillus thuringiensis form spores encased in a protein coat surrounded by a balloon-like exosporium. These structures mediate spore interactions with its environment, including the host immune system, control the transit of molecules that trigger germination and thus are essential for the spore life cycle. Formation of the coat and exosporium has been traditionally visualized by transmission electronic microscopy on fixed cells. Recently, we showed that assembly of the exosporium can be directly observed in live B. cereus cells by super resolution-structured illumination microscopy (SR-SIM) using the membrane MitoTrackerGreen (MTG) dye. Here, we demonstrate that the different steps of coat formation can also be visualized by SR-SIM using MTG and SNAP-cell TMR-star dyes during B. cereus sporulation. We used these markers to characterize a subpopulation of engulfment-defective B. cereus cells that develops at a suboptimal sporulation temperature. Importantly, we predicted and confirmed that synthesis and accumulation of coat material, as well as synthesis of the σK-dependent protein BxpB, occur in cells arrested during engulfment. These results suggest that, unlike the well-studied model organism Bacillus subtilis, the activity of σK is not strictly linked to the state of forespore development in B. cereus.publishersversionpublishe

Les entreprises agro-alimentaires bretonnes dans la concurrence internationale : éléments pour une stratégie à moyen terme

*Observatoire Economique des IAA 111 bd Delattre de Tassigny 35000 RENNES (FRA) Diffusion du document : Observatoire Economique des IAA 111 bd Delattre de Tassigny 35000 RENNES (FRA)Dans le cadre des études entreprises à l'initiative du Comité Économique et Social sur "les perspectives à l'horizon 2000 de l'agriculture, de l'agroalimentaire et de l'aménagement rural en Bretagne", un groupe de travail a été constitué pour engager une réflexion sur les entreprises agroalimentaires bretonnes dans la concurrence internationale. L'objectif principal de cette réflexion est l'élaboration d'une stratégie à moyen terme qui devrait permettre à l'industrie bretonne de tirer le meilleur parti de l'achèvement du marché intérieur européen

Les entreprises agro-alimentaires bretonnes dans la concurrence internationale : éléments pour une stratégie à moyen terme

Dans le cadre des études entreprises à l'initiative du Comité Économique et Social sur "les perspectives à l'horizon 2000 de l'agriculture, de l'agroalimentaire et de l'aménagement rural en Bretagne", un groupe de travail a été constitué pour engager une réflexion sur les entreprises agroalimentaires bretonnes dans la concurrence internationale. L'objectif principal de cette réflexion est l'élaboration d'une stratégie à moyen terme qui devrait permettre à l'industrie bretonne de tirer le meilleur parti de l'achèvement du marché intérieur européen

Les entreprises agro-alimentaires bretonnes dans la concurrence internationale : éléments pour une stratégie à moyen terme

*Observatoire Economique des IAA 111 bd Delattre de Tassigny 35000 RENNES (FRA) Diffusion du document : Observatoire Economique des IAA 111 bd Delattre de Tassigny 35000 RENNES (FRA)Dans le cadre des études entreprises à l'initiative du Comité Économique et Social sur "les perspectives à l'horizon 2000 de l'agriculture, de l'agroalimentaire et de l'aménagement rural en Bretagne", un groupe de travail a été constitué pour engager une réflexion sur les entreprises agroalimentaires bretonnes dans la concurrence internationale. L'objectif principal de cette réflexion est l'élaboration d'une stratégie à moyen terme qui devrait permettre à l'industrie bretonne de tirer le meilleur parti de l'achèvement du marché intérieur européen

Les entreprises agro-alimentaires bretonnes dans la concurrence internationale : éléments pour une stratégie à moyen terme

Dans le cadre des études préparatoires à l'élaboration du XIe plan breton, un groupe de travail a été constitué pour engager une réflexion sur les entreprises agro-alimentaires bretonnes dans la concurrence internationale. L'objectif principal de cette réflexion est l'élaboration d'une stratégie à moyen terme qui devrait permettre à l'industrie bretonne de tirer le meilleur parti de l'achèvement du marché intérieur européen. Ce document de travail aborde quelques problèmes liés à l'échéance 1993 en examinant le point de vue des industriels et analysant ensuite les processus et les mécanismes à travers lesquels va se résumer la confrontation des firmes, en insistant sur l'innovation et la productivité dans l'industrie, le choix des produits et les rapprochements interentreprises. Nous envisagerons ensuite quelques mesures favorables au développement des PME

Des Amap aux supermarchés coopératifs, les consommateurs s'engagent

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Word processing in Parkinson's disease is impaired for action verbs but not for concrete nouns.: Action word processing in Parkinson's Disease

International audienceRecent studies have demonstrated that processing of action words recruits cortical motor regions that are also involved in the planning and execution of the actions words refer to. The functional role of these regions in word understanding remains, however, to be clarified. The present study investigates this issue by examining the impact of Parkinson's disease (PD) on lexical decision performance for action words, relative to concrete nouns, in a masked priming paradigm. Priming effects for the two word categories were measured in non-demented PD patients off and on dopaminergic treatment, and in healthy participants. Our results revealed that although overall performances did not differ between verbs and nouns, priming effects showed a clear dissociation between word categories. While priming for concrete nouns was not affected by Levodopa intake, it dissociated as a function of treatment for action verbs. No priming was actually obtained for action verbs in PD patients off dopaminergic treatment. Following Levodopa intake, this deficit recovered, however, because priming effects for verbs became comparable to those for concrete nouns and similar to performance of healthy participants. Overall, this study thus brings compelling evidence that processing lexico-semantic information about action words depends on the integrity of the motor system

Draft Genome Sequences of 18 Psychrotolerant and 2 Thermotolerant Strains Representative of Particular Ecotypes in the Bacillus cereus Group

Bacteria from the Bacillus cereus group exhibit genetic and physiological diversity through different ecotypes. Here, we present the draft genome sequences of 20 bacterial strains belonging to the contrasted psychrotolerant and thermotolerant ecotypes

Insights into the Structure and Protein Composition of Moorella thermoacetica Spores Formed at Different Temperatures

The bacterium Moorella thermoacetica produces the most heat-resistant spores of any spoilage-causing microorganism known in the food industry. Previous work by our group revealed that the resistance of these spores to wet heat and biocides was lower when spores were produced at a lower temperature than the optimal temperature. Here, we used electron microcopy to characterize the ultrastructure of the coat of the spores formed at different sporulation temperatures; we found that spores produced at 55 °C mainly exhibited a lamellar inner coat tightly associated with a diffuse outer coat, while spores produced at 45 °C showed an inner and an outer coat separated by a less electron-dense zone. Moreover, misarranged coat structures were more frequently observed when spores were produced at the lower temperature. We then analyzed the proteome of the spores obtained at either 45 °C or 55 °C with respect to proteins putatively involved in the spore coat, exosporium, or in spore resistance. Some putative spore coat proteins, such as CotSA, were only identified in spores produced at 55 °C; other putative exosporium and coat proteins were significantly less abundant in spores produced at 45 °C. Altogether, our results suggest that sporulation temperature affects the structure and protein composition of M. thermoacetica spores