Related Experiment Video
Updated: Feb 1, 2026
08:34
Investigating the Alleviating Effects of Bacillus cereus Administration on Colitis through Gut Microbiota Modulation
Published on: July 27, 2022
1.3K
GABA-modulating bacteria of the human gut microbiota
Philip Strandwitz1, Ki Hyun Kim2,3, Darya Terekhova4
1Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA, USA. p.strandwitz@northeastern.edu.
Nature Microbiology
|December 12, 2018
Summary
The gut bacterium KLE1738 requires gamma-aminobutyric acid (GABA) for growth, a neurotransmitter produced by Bacteroides species. Gut Bacteroides abundance correlates with brain activity in major depressive disorder patients.
Area of Science:
- Microbiology and Neuroscience
- Gut Microbiota and Host Physiology
Background:
- The human gut microbiota plays a crucial role in host functions, including immune and nervous system regulation.
- A significant portion of gut microbial species remain uncultured, hindering the understanding of their biological roles.
- Unculturability is often attributed to the lack of essential growth factors present in the in situ environment.
Purpose of the Study:
- To identify essential growth factors for uncultured gut bacteria.
- To investigate the role of neurotransmitters in microbial growth and metabolism.
- To explore the link between gut microbiota composition, GABA production, and major depressive disorder.
Main Methods:
- Co-culturing techniques were employed to isolate the uncultured bacterium KLE1738.
- Bioassay-guided purification identified gamma-aminobutyric acid (GABA) as a key growth factor for KLE1738.
- Genome analysis, metabolic modeling, transcriptome analysis of human stool, and functional MRI in patients were utilized.
Main Results:
- Gamma-aminobutyric acid (GABA) was identified as the sole nutrient supporting the growth of the uncultured gut bacterium KLE1738.
- Bacteroides species were found to be significant producers of GABA, with multiple other genera capable of producing or consuming it.
- Active expression of GABA-producing pathways was observed in Bacteroides, Parabacteroides, and Escherichia species in healthy individuals.
- A negative correlation was found between fecal Bacteroides abundance and brain signatures associated with major depressive disorder.
Conclusions:
- Gamma-aminobutyric acid (GABA) is a critical growth factor for certain uncultured gut bacteria, linking neurotransmitter metabolism to microbial ecology.
- The gut microbiota, particularly Bacteroides species, actively produces GABA, influencing the gut-brain axis.
- Alterations in gut Bacteroides abundance may be associated with neurological conditions like major depressive disorder via GABA-mediated pathways.
Related Concept Videos
02:40The Tree of Life - Bacteria, Archaea, Eukaryotes
38.4K
The “tree of life” describes the evolution of life and the evolutionary relationships between organisms. The root of the tree is the common ancestor to all life on Earth. All other species radiate from this point, much like the branches of a tree. The numerous tips of these branches on the tree of life represent every living, or extant, species. Extinct species, which are species that no longer exist, can be found towards the center of the tree. Currently, these organisms, both...
38.4K
01:18Other Unique Bacteria
438
Magnetic bacteria exhibit a directed movement called magnetotaxis, driven by structures called magnetosomes. These magnetosomes consist of chains of magnetic particles made of either magnetite (Fe₃O₄) or greigite (Fe₃S₄) and are organized in a linear conformation by a protein scaffold within invaginations of the cell membrane. The bacteria align along the north–south magnetic field lines, much like a compass needle. They are typically microaerophilic or anaerobic...
438
01:05Physiology of Enteric Nervous System and Gut Health
978
The gastrointestinal tract, responsible for the digestion and absorption of nutrients, is safeguarded by the intestinal barrier, which consists of secretory, physical, and immune components. At the forefront is the secretory barrier, composed of essential elements such as mucus, gut microbiota, and defense proteins. They collaborate to break down food particles, facilitate nutrient absorption, and maintain optimal gut health. These secretory components ensure the smooth functioning of the...
978
01:24Biosynthesis in Bacteria
662
Biosynthesis in bacteria is a fundamental anabolic process that generates essential macromolecules, including proteins, nucleic acids, lipids, and polysaccharides. These macromolecules are critical for cellular growth, replication, and function. The process is tightly regulated and energetically linked to catabolic pathways to ensure optimal resource utilization.Biosynthetic pathways begin with precursor metabolites such as pyruvate, acetyl-CoA, and glucose-6-phosphate derived from glycolysis,...
662
01:21Hyperthermophilic Bacteria
545
Domain Bacteria includes some unique hyperthermophilic species. They exhibit remarkable adaptations that enable survival in extreme environments.Thermotoga species are rod-shaped, gram-negative, non-sporulating hyperthermophiles that form a sheath-like envelope called a toga. They ferment sugars or starch, producing lactate, acetate, CO₂, and H₂, and can also grow via anaerobic respiration using H₂ and ferric iron. Found in hot springs and hydrothermal vents, over 20% of their...
545
02:11The Roles of Bacteria and Fungi in Plant Nutrition
47.3K
Plants have the impressive ability to create their own food through photosynthesis. However, plants often require assistance from organisms in the soil to acquire the nutrients they need to function correctly. Both bacteria and fungi have evolved symbiotic relationships with plants that help the species to thrive in a wide variety of environments.
47.3K