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Functional advantages conferred by extracellular prokaryotic membrane vesicles.
Andrew J Manning1, Meta J Kuehn
1Department of Biochemistry, Duke University Medical Center, Durham, NC 27710, USA.
Journal of Molecular Microbiology and Biotechnology
|April 26, 2013
Summary
Prokaryotic cells, once thought to lack organelles, actually utilize membrane vesicles. These extracellular vesicles perform vital functions, challenging the traditional cell biology dogma.
Area of Science:
- Cell Biology
- Microbiology
Background:
- Traditionally, prokaryotic cells are defined by the absence of subcellular organelles, distinguishing them from eukaryotic cells.
- Recent research has challenged this long-standing dogma regarding prokaryotic cell structure.
Purpose of the Study:
- To review the diverse functions of extracellular membrane-bound vesicles in prokaryotes.
- To compare these extracellular organelles with intracellular prokaryotic membrane-bound structures.
Main Methods:
- Literature review of research on bacterial and archaeal membrane vesicles.
- Comparative analysis of extracellular vesicle functions versus intracellular organelles.
Main Results:
- Gram-negative, Gram-positive, and archaeal cells produce extracellular vesicles.
- These vesicles mediate DNA binding/delivery, virulence factor transport, antimicrobial defense, and toxic protein removal.
- Intracellular organelles in bacteria are involved in light harvesting and magnetosome formation.
Conclusions:
- Extracellular vesicles are multifunctional organelles that play significant roles in prokaryotic physiology.
- Understanding these microbial tools is crucial for comprehending polymicrobial interactions.
Related Concept Videos
01:37Eukaryotic Compartmentalization
One of the distinguishing features of eukaryotic cells is that they contain membrane-bound organelles, such as the nucleus and mitochondria, that carry out specialized functions. Since biological membranes are only selectively permeable to solutes, they help create a compartment with controlled conditions inside an organelle. These microenvironments are tailored to the organelle's specific functions and help isolate them from the surrounding cytosol.
For example, lysosomes in the animal cells...
For example, lysosomes in the animal cells...
01:46Eukaryotic Compartmentalizations
One of the distinguishing features of eukaryotic cells is that they contain membrane-bound organelles, such as the nucleus and mitochondria, that carry out specialized functions. Since biological membranes are only selectively permeable to solutes, they help create a compartment with controlled conditions inside an organelle. These microenvironments are tailored to the organelle's specific functions and help isolate them from the surrounding cytosol.
For example, lysosomes in the animal cells...
For example, lysosomes in the animal cells...
01:51Prokaryotic Cells
Prokaryotes are small unicellular organisms that include the domains—Archaea and Bacteria. Bacteria include many common organisms, such as Salmonella and E. coli, while the Archaea include extremophiles that live in harsh environments, such as volcanic springs.
Like eukaryotic cells, all prokaryotic cells are surrounded by a plasma membrane, have genetic material in the form of single, circular DNA, a cytoplasm that fills the interior of the cell, and ribosomes that synthesize proteins.
Like eukaryotic cells, all prokaryotic cells are surrounded by a plasma membrane, have genetic material in the form of single, circular DNA, a cytoplasm that fills the interior of the cell, and ribosomes that synthesize proteins.
01:28Prokaryotic Cells
Prokaryotes are small unicellular organisms that include the domains — Archaea and Bacteria. Bacteria include many common microorganisms, such as Salmonella and E. coli, while the Archaea include extremophiles that live in harsh environments, such as volcanic springs.
Like eukaryotic cells, all prokaryotic cells are surrounded by a plasma membrane, have genetic material in the form of single, circular DNA, a cytoplasm that fills the interior of the cell, and ribosomes that synthesize proteins.
Like eukaryotic cells, all prokaryotic cells are surrounded by a plasma membrane, have genetic material in the form of single, circular DNA, a cytoplasm that fills the interior of the cell, and ribosomes that synthesize proteins.
01:33Overview of Secretory Vesicles
Secretory vesicles, also known as dense core vesicles (DCVs), are membrane-bound vesicles that transport secretory proteins, such as hormones or neurotransmitters. Regulated secretory vesicles transport proteins from the trans-Golgi network to the exterior of the cell. Proteins present in regulated secretory vesicles are required to be rapidly exocytosed in large amounts upon a specific stimulus.
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
Various proteins regulate the aggregation of molecules inside the secretory vesicles. Chromogranins...
01:36Overview of Exosomes
Exosomes are stable, lipid bilayer-enclosed vesicles capable of crossing biological barriers. They can carry a wide range of molecules required for intercellular communication. Once exosomes are released from the cell where they originated, they enter a recipient cell through various pathways such as fusion, receptor-mediated endocytosis, macropinocytosis, and phagocytosis.
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