Related Experiment Video
Updated: Apr 18, 2026
12:12
Transformation of Probiotic Yeast and Their Recovery from Gastrointestinal Immune Tissues Following Oral Gavage in Mice
Published on: February 8, 2016
13.2K
Human gut Bacteroidetes can utilize yeast mannan through a selfish mechanism
Fiona Cuskin1,2, Elisabeth C Lowe1, Max J Temple1
1Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4HH, U.K.
Nature
|January 9, 2015
Summary
Yeast alpha-mannan feeds the gut bacterium Bacteroides thetaiotaomicron. This bacterium breaks down yeast glycans using specific enzymes, impacting human gut ecology.
Area of Science:
- Microbiology
- Human Microbiome Research
- Glycobiology
Background:
- Yeast alpha-mannan is a complex polysaccharide found in yeast cell walls.
- The role of yeast mannan in the human gut microbiota remains largely unexplored.
- Bacteroides thetaiotaomicron is a prevalent Gram-negative bacterium in the human gut.
Purpose of the Study:
- To investigate the utilization of yeast alpha-mannan by human gut bacteria.
- To elucidate the metabolic pathways involved in yeast mannan breakdown by Bacteroides thetaiotaomicron.
- To understand the ecological implications of yeast mannan consumption in the human microbiota.
Main Methods:
- Biochemical analysis of alpha-mannan degradation.
- Targeted gene disruption in Bacteroides thetaiotaomicron.
- Co-culturing experiments with gut bacteria.
- Genomic comparison of microbial species.
Main Results:
- Yeast alpha-mannan serves as a nutrient source for Bacteroides thetaiotaomicron.
- A model for alpha-mannan breakdown involves initial surface cleavage and subsequent mannose depolymerization by periplasmic enzymes.
- B. thetaiotaomicron exhibits a 'selfish' catabolic strategy for yeast mannan.
- A subset of successful gut microbes has evolved to metabolize sterically-hindered yeast glycans.
Conclusions:
- Bacteroides thetaiotaomicron can efficiently metabolize yeast alpha-mannan.
- The ability to consume yeast glycans may be an adaptation to the inclusion of yeast in the human diet.
- This microbial adaptation influences the human gut ecosystem's dynamics.
Related Concept Videos
01:18Functions of the Gut Microbiota
106
The gut microbiota includes trillions of microorganisms that colonize the human gastrointestinal tract, including bacteria, archaea, viruses, and fungi. This complex ecosystem plays a critical role in maintaining intestinal and systemic health. Most of these microbes inhabit the large intestine, establishing a relatively stable and diverse community that contributes to gut homeostasis through various metabolic, immunological, and protective mechanisms.Dominant bacterial phyla, such as...
106
01:27Microbiota of the Large Intestine
80
The large intestine hosts the most densely populated microbial ecosystem in the human body. This complex community primarily consists of anaerobic bacteria, with Bacillota (formerly Firmicutes) and Bacteroidota (formerly Bacteroidetes) as the predominant groups. The distribution of these microbes varies along different sections of the large intestine, influenced by local environmental factors such as oxygen availability and nutrient composition.The cecum, located at the beginning of the large...
80
01:26Microbes and Methanogenesis
74
Methanogenesis is a critical microbial process in anaerobic ecosystems responsible for the biological production of methane, a potent greenhouse gas and valuable biofuel. This metabolic pathway is primarily facilitated by methanogenic archaea, which thrive in anoxic environments such as wetlands, sediments, and animal gastrointestinal tracts. The absence of oxygen in these habitats prevents aerobic respiration, thereby favoring alternative biochemical pathways for organic matter degradation.In...
74
01:25Microbial Interactions: Mutualism
62
Mutualism is a symbiotic interaction in which all participating organisms benefit. These relationships can be obligate or facultative and are fundamental to ecosystem functions across diverse biological systems.Plant–Fungi MutualismOne well-known example is the association between plant roots and mycorrhizal fungi, such as Rhizophagus species. The fungal hyphae penetrate the root hairs and the epidermis, forming an extensive hyphal network that establishes a symbiotic association. Through...
62
01:26Microbial Interactions: Cooperation
48
Microbial cooperation involves beneficial interactions in which different species work together for individual or mutual advantage. These interactions can profoundly influence ecological dynamics and evolutionary processes, and they are essential to many pathogenic and symbiotic relationships.Nematode–Bacteria CooperationA striking example is the relationship between the Gram-negative bacterium Xenorhabdus nematophila and the parasitic nematode Steinernema carpocapsae. Juvenile nematodes...
48
01:29Fungal Group Zygomycota
2.2K
Zygomycota, previously classified as a distinct fungal group, are primarily terrestrial, saprophytic molds that play a crucial role as decomposers. Recent phylogenetic studies have revealed that these fungi are now divided into two major clades — Mucoromycota, which includes many symbiotic species, and Zoopagomycota, which primarily consists of parasitic and pathogenic fungi. These groups exhibit distinct ecological roles and reproductive strategies while sharing key structural and...
2.2K