The biofilm-associated surface protein Esp of Enterococcus faecalis forms amyloid-like fibers

Functional amyloids are considered as common building block structures of the biofilm matrix in different bacteria. In previous work, we have shown that the staphylococcal surface protein Bap, a member of the Biofilm-Associated Proteins (BAP) family, is processed and the fragments containing the N-terminal region become aggregation-prone and self-assemble into amyloid-like structures. Here, we report that Esp, a Bap-orthologous protein produced by Enterococcus faecalis, displays a similar amyloidogenic behavior. We demonstrate that at acidic pH the N-terminal region of Esp forms aggregates with an amyloid-like conformation, as evidenced by biophysical analysis and the binding of protein aggregates to amyloid-indicative dyes. Expression of a chimeric protein, with its Esp N-terminal domain anchored to the cell wall through the R domain of clumping factor A, showed that the Esp N-terminal region is sufficient to confer multicellular behavior through the formation of an extracellular amyloid-like material. These results suggest that the mechanism of amyloid-like aggregation to build the biofilm matrix might be widespread among BAP-like proteins. This amyloid-based mechanism may not only have strong relevance for bacteria lifestyle but could also contribute to the amyloid burden to which the human physiology is potentially exposed.This research was supported by grants RTI2018-096011-B-I00 and BIO2017-83035-R from the Spanish Ministry of Science, Innovation and Universities, and Proyecto Intramural Incorporación-2018 CSIC

Insights into pneumococcal fratricide from the crystal structures of the modular killing factor LytC

7 pags, 3 figs, 1 tabThe first structure of a pneumococcal autolysin, that of the LytC lysozyme, has been solved in ternary complex with choline and a pneumococcal peptidoglycan (PG) fragment. The active site of the hydrolase module is not fully exposed but is oriented toward the choline-binding module, which accounts for its unique in vivo features in PG hydrolysis, its activation and its regulatory mechanisms. Because of the unusual hook-shaped conformation of the multimodular protein, it is only able to hydrolyze non-cross-linked PG chains, an assertion validated by additional experiments. These results explain the activation of LytC by choline-binding protein D (CbpD) in fratricide, a competence-programmed mechanism of predation of noncompetent sister cells. The results provide the first structural insights to our knowledge into the critical and central function that LytC plays in pneumococcal virulence and explain a long-standing puzzle of how murein hydrolases can be controlled to avoid self-lysis during bacterial growth and division. © 2010 Nature America, Inc. All rights reserved.This work was supported by grants from the Spanish Ministry of Science and Technology (BFU2008-01711, SAF2006-00390), EU-CP223111 (CAREPNEUMO, European Union), the COMBACT program (S-BIO-0260/2006) and CIBER de Enfermedades Respiratorias (CIBERES). CIBERES is an initiative of Instituto de Salud Carlos III. The work in the US was supported by the US National Institutes of Health. W.V. was supported by the European Commission (EUR-INTAFAR project). I.P.-D. was a fellow of the Consejo Superior de Investigaciones Científicas

Casos de estudio en México y Latinoamérica

Ante la presencia de conflictos sociales y territoriales, las comunidades organizadas buscan estrategias de solución y confrontación. Es el estudio de dichos movimientos, lo que motiva a la publicación de éste libro: Respuestas comunitarias ante conflictos ambientales. Casos de estudio en México y Latinoamérica, reúne catorce textos que analizan las respuestas sociales y documentan la acción colectiva de comunidades que se han organizado para autogestionar soluciones ante conflictos territoriales, económicos y ambientales, en su propio entorno. Las aportaciones de investigadores y activistas, desde enfoques teóricos y metodológicos particulares, exponen casos de estudio sobre organizaciones formales e informales que se han conformado para afrontar los retos que representan proyectos productivos como fábricas cementeras, mineras, puertos, productores de energía, entre otros. Los enfoques analíticos tocan también temas nodales en el estudio de la acción colectiva como la ética, el despojo, los derechos humanos y las estrategias de comunicación y visibilización. Este material, que reúne estudios hechos en distintos lugares de México y Latinoamérica, es un compendio de métodos de investigación y un acercamiento al estudio de los movimientos sociales.UAEMEX, CONACyT, SE

Fitness cost evolution of natural plasmids of staphylococcus aureus

© 2021 Dorado-Morales et al.Plasmids have largely contributed to the spread of antimicrobial resistance genes among Staphylococcus strains. Knowledge about the fitness cost that plasmids confer on clinical staphylococcal isolates and the coevolutionary dynamics that drive plasmid maintenance is still scarce. In this study, we aimed to analyze the initial fitness cost of plasmids in the bacterial pathogen Staphylococcus aureus and the plasmid-host adaptations that occur over time. For that, we first designed a CRISPR (clustered regularly interspaced palindromic repeats)-based tool that enables the removal of native S. aureus plasmids and then transferred three different plasmids isolated from clinical S. aureus strains to the same-background clinical cured strain. One of the plasmids, pUR2940, obtained from a livestock-associated methicillin-resistant S. aureus (LA-MRSA) ST398 strain, imposed a significant fitness cost on both its native and the new host. Experimental evolution in a nonselective medium resulted in a high rate pUR2940 loss and selected for clones with an alleviated fitness cost in which compensatory adaptation occurred via deletion of a 12.8-kb plasmid fragment, contained between two ISSau10 insertion sequences and harboring several antimicrobial resistance genes. Overall, our results describe the relevance of plasmid-borne insertion sequences in plasmid rearrangement and maintenance and suggest the potential benefits of reducing the use of antibiotics both in animal and clinical settings for the loss of clinical multidrug resistance plasmids.This work was financially supported by the Spanish Ministry of Science, Innovation and Universities grants BIO2014-53530-R and BIO2017-83035-R (Agencia Española de Investigación/Fondo Europeo de Desarrollo Regional, European Union) to I.L. and C.S. P.D.-M. was supported by an F.P.I. (BES-2015-072859) contract from the Spanish Ministry of Science, Innovation and Universities

Inhibición selectiva de la actividad lipasa por una mini-proteína altamente conservada en el género Staphylococcus

Resumen del trabajo presentado en la XIII Reunión del Grupo de Microbiología Molecular de La SEM, celebrada en Granada (España), del 7 al 9 de septiembre de 202

Supplementary Information: A highly diverse, desert-like microbial biocenosis on solar panels in a Mediterranean city

Supplementary Tables: Table S1. Taxonomical classification of the bacterial species isolated from solar panel samples according to 16S rDNA sequence similarity. Table S2. Summary of sequencing statistics from the 16S/18S profile analysis. Table S3. Summary of sequencing statistics from the shotgun metagenomic sequencing of solar panels 1 and 3 in 2014. Table S4. Differentially expressed proteins between day- and night-collected samples.Supplementary Figures: Figure S1. Microbial colonies growing on LB incubated at room temperature for two weeks (A). Case example of growth restoration in nearby-grown isolates under conditions of extreme pH. A local buffering of the pH of the plate is observed (B). Figure S2. Stress tests results data matrix. The growth of the 53 strains isolated from the solar panels under particular stress conditions was compared to that of a control strain (XL1-Blue E. coli strain). Green colour (from light to dark) indicates better growth than the control (from slightly to strongly better growth). Symbols ‘+’ indicate cases of growth restoration by another isolate. Two independent experiments were performed for each test. Strains are numbered according to Table S1. Figure S3. Taxonomic diversity of one of the panels (panel 1) sampled in the summer solstice of 2014 as deduced from shotgun metagenomic sequencing.Peer reviewe