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Enigmatic Pilus-Like Endospore Appendages of Bacillus cereus Group Species

The endospores (spores) of many Bacillus cereus sensu lato species are decorated with multiple hair/pilus-like appendages. Although they have been observed for more than 50 years, all efforts to characterize these fibers in detail have failed until now, largely due to their extraordinary resilience...

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Autores principales: Zegeye, Ephrem Debebe, Pradhan, Brajabandhu, Llarena, Ann-Katrin, Aspholm, Marina
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8619143/
https://www.ncbi.nlm.nih.gov/pubmed/34830248
http://dx.doi.org/10.3390/ijms222212367
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author Zegeye, Ephrem Debebe
Pradhan, Brajabandhu
Llarena, Ann-Katrin
Aspholm, Marina
author_facet Zegeye, Ephrem Debebe
Pradhan, Brajabandhu
Llarena, Ann-Katrin
Aspholm, Marina
author_sort Zegeye, Ephrem Debebe
collection PubMed
description The endospores (spores) of many Bacillus cereus sensu lato species are decorated with multiple hair/pilus-like appendages. Although they have been observed for more than 50 years, all efforts to characterize these fibers in detail have failed until now, largely due to their extraordinary resilience to proteolytic digestion and chemical solubilization. A recent structural analysis of B. cereus endospore appendages (Enas) using cryo-electron microscopy has revealed the structure of two distinct fiber morphologies: the longer and more abundant “Staggered-type” (S-Ena) and the shorter “Ladder-like” type (L-Ena), which further enabled the identification of the genes encoding the S-Ena. Ena homologs are widely and uniquely distributed among B. cereus sensu lato species, suggesting that appendages play important functional roles in these species. The discovery of ena genes is expected to facilitate functional studies involving Ena-depleted mutant spores to explore the role of Enas in the interaction between spores and their environment. Given the importance of B. cereus spores for the food industry and in medicine, there is a need for a better understanding of their biological functions and physicochemical properties. In this review, we discuss the current understanding of the Ena structure and the potential roles these remarkable fibers may play in the adhesion of spores to biotic and abiotic surfaces, aggregation, and biofilm formation.
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spelling pubmed-86191432021-11-27 Enigmatic Pilus-Like Endospore Appendages of Bacillus cereus Group Species Zegeye, Ephrem Debebe Pradhan, Brajabandhu Llarena, Ann-Katrin Aspholm, Marina Int J Mol Sci Review The endospores (spores) of many Bacillus cereus sensu lato species are decorated with multiple hair/pilus-like appendages. Although they have been observed for more than 50 years, all efforts to characterize these fibers in detail have failed until now, largely due to their extraordinary resilience to proteolytic digestion and chemical solubilization. A recent structural analysis of B. cereus endospore appendages (Enas) using cryo-electron microscopy has revealed the structure of two distinct fiber morphologies: the longer and more abundant “Staggered-type” (S-Ena) and the shorter “Ladder-like” type (L-Ena), which further enabled the identification of the genes encoding the S-Ena. Ena homologs are widely and uniquely distributed among B. cereus sensu lato species, suggesting that appendages play important functional roles in these species. The discovery of ena genes is expected to facilitate functional studies involving Ena-depleted mutant spores to explore the role of Enas in the interaction between spores and their environment. Given the importance of B. cereus spores for the food industry and in medicine, there is a need for a better understanding of their biological functions and physicochemical properties. In this review, we discuss the current understanding of the Ena structure and the potential roles these remarkable fibers may play in the adhesion of spores to biotic and abiotic surfaces, aggregation, and biofilm formation. MDPI 2021-11-16 /pmc/articles/PMC8619143/ /pubmed/34830248 http://dx.doi.org/10.3390/ijms222212367 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Review
Zegeye, Ephrem Debebe
Pradhan, Brajabandhu
Llarena, Ann-Katrin
Aspholm, Marina
Enigmatic Pilus-Like Endospore Appendages of Bacillus cereus Group Species
title Enigmatic Pilus-Like Endospore Appendages of Bacillus cereus Group Species
title_full Enigmatic Pilus-Like Endospore Appendages of Bacillus cereus Group Species
title_fullStr Enigmatic Pilus-Like Endospore Appendages of Bacillus cereus Group Species
title_full_unstemmed Enigmatic Pilus-Like Endospore Appendages of Bacillus cereus Group Species
title_short Enigmatic Pilus-Like Endospore Appendages of Bacillus cereus Group Species
title_sort enigmatic pilus-like endospore appendages of bacillus cereus group species
topic Review
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8619143/
https://www.ncbi.nlm.nih.gov/pubmed/34830248
http://dx.doi.org/10.3390/ijms222212367
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