Related Experiment Video
Updated: Apr 19, 2026
06:38
A Novel Method for the Culture and Polarized Stimulation of Human Intestinal Mucosa Explants
Published on: May 1, 2013
13.7K
Sortase-deficient lactobacilli: effect on immunomodulation and gut retention.
Emma K Call1, Yong Jun Goh1, Kurt Selle1
1Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, NC, USA.
Microbiology (Reading, England)
|December 16, 2014
Summary
Sortase-dependent proteins are crucial for probiotic bacteria like Lactobacillus to adhere to the gut and interact with the immune system. Deleting the sortase gene (srtA) reduced bacterial gut retention and immune response.
Area of Science:
- Microbiology
- Immunology
- Gastroenterology
Background:
- Surface proteins of probiotic microbes, such as Lactobacillus acidophilus and Lactobacillus gasseri, are key for gut adherence and host communication.
- Sortase enzymes are critical for anchoring surface proteins, influencing bacterial interactions with the host's mucosal immune system.
Purpose of the Study:
- To investigate the role of the sortase gene (srtA) and its dependent proteins in the gastrointestinal tract retention and immune modulation of Lactobacillus acidophilus and Lactobacillus gasseri.
- To characterize the impact of sortase inactivation on bacterial adhesion, survival, and inflammatory responses.
Main Methods:
- Identification of the srtA gene and prediction of sortase-dependent proteins in L. acidophilus and L. gasseri.
- Construction of ΔsrtA deletion mutants using a counterselective gene replacement system.
- In vitro assessment of bacterial growth, survival in simulated gastrointestinal juices, and adhesion to porcine mucin.
- In vitro analysis of cytokine production (TNF-α, IL-12) by murine dendritic cells exposed to wild-type and mutant strains.
- In vivo co-colonization experiments in germ-free mice to evaluate gut retention.
Main Results:
- Inactivation of the sortase gene (srtA) did not affect bacterial growth or survival in simulated gastrointestinal conditions.
- ΔsrtA mutants exhibited significantly reduced adhesion to porcine mucin in vitro.
- Exposure of dendritic cells to ΔsrtA mutants resulted in lower pro-inflammatory cytokine (TNF-α, IL-12) induction compared to parent strains.
- In vivo studies showed a one-log reduction in the gut population of the L. acidophilus ΔsrtA mutant, indicating impaired retention.
Conclusions:
- Sortase-dependent proteins play a significant role in the gastrointestinal tract retention of probiotic Lactobacillus species.
- The sortase system influences bacterial adhesion to mucin and modulates host immune responses.
- Targeting sortase-dependent proteins could be a strategy to enhance the efficacy of probiotic bacteria.
Related Concept Videos
01:22Probiotics
244
Probiotics are live, non-pathogenic microorganisms that confer health benefits by modulating the gut microbiota. The human gastrointestinal tract harbors a complex microbial ecosystem, and the balance of this microbiota is crucial for digestive and systemic health. Among the most extensively studied and utilized probiotics are species formerly classified within the genera Lactobacillus and Bifidobacterium. These organisms not only naturally colonize the human gut but are also consumed through...
244
01:27Microbiota of the Stomach and Small Intestine
67
The human gastrointestinal (GI) tract is characterized by distinct physicochemical conditions that shape its microbial communities. Among these, the stomach presents a particularly challenging environment for microbial colonization due to its highly acidic pH, ranging from 1 to 3. This extreme acidity effectively limits microbial density. However, certain acid-tolerant microorganisms are capable of surviving in this niche. Notably, Helicobacter pylori can colonize the gastric mucosa,...
67
01:18Functions of the Gut Microbiota
111
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...
111