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Enigmatic Pilus-Like Endospore Appendages of Bacillus cereus Group Species

Ephrem Debebe Zegeye1, Brajabandhu Pradhan2,3, Ann-Katrin Llarena1

  • 1Department of Paraclinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), P.O. Box 5003, 1432 Ås, Norway.

International Journal of Molecular Sciences
|November 27, 2021
PubMed

Insights

Researchers have identified the genes for Bacillus cereus endospore appendages (Enas), revealing their structure and potential roles in spore adhesion and biofilm formation. This breakthrough aids future functional studies of these resilient bacterial structures.

Area of Science:

  • Microbiology
  • Structural Biology
  • Bacterial Pathogenesis

Background:

  • Bacillus cereus sensu lato endospores possess hair-like appendages (Enas) observed for decades but poorly characterized due to their resilience.
  • Previous attempts to study Enas were hindered by their resistance to degradation and solubilization methods.

Purpose of the Study:

  • To elucidate the structure and genetic basis of Bacillus cereus endospore appendages (Enas).
  • To explore the potential functional roles of Enas in spore-surface interactions, adhesion, aggregation, and biofilm formation.
  • To provide a foundation for future functional studies of Enas using genetic manipulation.

Main Methods:

  • Cryo-electron microscopy was employed for high-resolution structural analysis of Enas.
  • Bioinformatic analysis was used to identify genes encoding the S-Ena type appendage.
  • Review of existing literature on Ena structure and potential functions.

Main Results:

  • Two distinct Ena morphologies were identified: Staggered-type (S-Ena) and Ladder-like (L-Ena).
  • Genes encoding the S-Ena were successfully identified, enabling further research.
  • Ena homologs are uniquely distributed across B. cereus sensu lato species.

Conclusions:

  • The structural and genetic characterization of Enas opens new avenues for understanding their biological significance.
  • Enas likely play crucial roles in spore adhesion, aggregation, and biofilm formation.
  • Further research on Enas is vital given the importance of B. cereus spores in food safety and medicine.
Keywords:
Bacillus cereusEnaappendageendosporepilispore

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