Presentation Information
[2EMT-04]Quantal secretion through membrane vesicles in bacteria
○Masanori Toyofuku1 (1. University of Tsukuba, Institute of Life and Environmental Sciences (Japan))
Keywords:
Membrane Vesicle,Communication,Phage,Quantal Secretion
Bacteria release membrane vesicles (MVs), nanoscale lipid particles that participate in diverse biological processes, including horizontal gene transfer, biofilm formation, nutrient acquisition, and immune modulation.
MV biology has become increasingly significant due to its impact on microbial interactions, stress responses, and community dynamics, as well as its emerging relevance in biotechnology and medicine, including drug delivery, vaccine development, and diagnostics.
Because MVs can concentrate and export biomolecules, this process has been described as a form of bacterial quantal secretion. Our previous work demonstrated that MVs can transport hydrophobic signaling molecules involved in intercellular communication. Although MVs are widespread across bacterial phyla, the mechanisms underlying their biogenesis and functional diversity remain incompletely understood. To address this gap, we have investigated MV formation pathways and their biological roles.
MV production in Gram-negative bacteria was traditionally attributed to outer membrane blebbing; however, our imaging-based studies identified a distinct mechanism. Instead of blebbing, a subpopulation of cells undergoes explosive cell lysis (ECL), in which membrane fragments rapidly reassemble into MVs. We found that ECL is triggered by endolysins, enzymes that degrade peptidoglycan and are best known for their role in bacteriophage-mediated lysis.
We further showed that endolysin-triggered MV formation is conserved in Gram-positive species, including Corynebacterium glutamicum, where MVs emerge through openings in the thick cell wall in a process termed bubbling cell death.
These mechanistic insights have enabled the engineering of MVs with customized compositions and improved production efficiency. Leveraging these principles, we developed a method to encapsulate molecules, including antibiotics, into MVs by actively inducing vesicle formation.
Current efforts focus on elucidating how bacteria internalize MV-associated cargo, and our findings suggest that uptake mechanisms vary depending on the nature of the cargo molecule.
MV biology has become increasingly significant due to its impact on microbial interactions, stress responses, and community dynamics, as well as its emerging relevance in biotechnology and medicine, including drug delivery, vaccine development, and diagnostics.
Because MVs can concentrate and export biomolecules, this process has been described as a form of bacterial quantal secretion. Our previous work demonstrated that MVs can transport hydrophobic signaling molecules involved in intercellular communication. Although MVs are widespread across bacterial phyla, the mechanisms underlying their biogenesis and functional diversity remain incompletely understood. To address this gap, we have investigated MV formation pathways and their biological roles.
MV production in Gram-negative bacteria was traditionally attributed to outer membrane blebbing; however, our imaging-based studies identified a distinct mechanism. Instead of blebbing, a subpopulation of cells undergoes explosive cell lysis (ECL), in which membrane fragments rapidly reassemble into MVs. We found that ECL is triggered by endolysins, enzymes that degrade peptidoglycan and are best known for their role in bacteriophage-mediated lysis.
We further showed that endolysin-triggered MV formation is conserved in Gram-positive species, including Corynebacterium glutamicum, where MVs emerge through openings in the thick cell wall in a process termed bubbling cell death.
These mechanistic insights have enabled the engineering of MVs with customized compositions and improved production efficiency. Leveraging these principles, we developed a method to encapsulate molecules, including antibiotics, into MVs by actively inducing vesicle formation.
Current efforts focus on elucidating how bacteria internalize MV-associated cargo, and our findings suggest that uptake mechanisms vary depending on the nature of the cargo molecule.
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