Related Experiment Video
Updated: Jun 19, 2026
05:19
Imaging Flow Cytometry to Study Microbial Autoaggregation
Published on: September 29, 2023
Autoaggregation response of Fusobacterium nucleatum
Justin Merritt1, Guoqing Niu, Toshinori Okinaga
1University of Oklahoma Health Sciences Center BRC364, 975 NE 10th St., Oklahoma City, OK 73104-5419, USA. justin-merritt@ouhsc.edu
Applied and Environmental Microbiology
|October 20, 2009
Summary
Fusobacterium nucleatum autoaggregation, a process linked to periodontal disease, activates a genetic program. This response may help the oral bacterium thrive in dense biofilm environments.
Area of Science:
- Microbiology
- Oral Biology
- Bacterial Genetics
Background:
- Fusobacterium nucleatum is a key oral bacterium implicated in periodontal disease.
- F. nucleatum exhibits significant adherence to other bacteria and host cells.
- The genetic response of F. nucleatum to aggregation interactions remains largely unexplored.
Purpose of the Study:
- To investigate the genetic changes in F. nucleatum during autoaggregation.
- To identify potential inhibitors of F. nucleatum autoaggregation.
- To understand the adaptive mechanisms of F. nucleatum in oral biofilms.
Main Methods:
- Coaggregation assays between F. nucleatum and Streptococcus species in a saliva-containing medium.
- Screening of coaggregation inhibitors, including L-lysine.
- Microarray analysis comparing planktonic and autoaggregated F. nucleatum cells.
- Validation of gene expression changes using real-time reverse transcription-PCR.
Main Results:
- F. nucleatum efficiently coaggregated with Streptococcus species and also exhibited significant autoaggregation.
- L-lysine was identified as a competitive inhibitor of F. nucleatum autoaggregation.
- Microarray analysis revealed approximately 100 differentially expressed genes in autoaggregated cells after 60 minutes.
- Gene expression changes were validated and found to be inducible in centrifuged cell pellets.
Conclusions:
- Autoaggregation in F. nucleatum triggers a distinct genetic program.
- This genetic response likely facilitates growth in high cell density environments, such as oral biofilms.
- Understanding these aggregation-induced genetic changes provides insights into F. nucleatum's role in oral health and disease.
Related Concept Videos
01:23Stringent Response in E. coli
Bacterial growth is closely tied to nutrient availability, with cells proliferating exponentially under favorable conditions and entering a stationary phase when resources become scarce. This transition is mediated by a regulatory mechanism known as the stringent response, which allows bacteria to adapt to nutrient deprivation by modulating gene expression and metabolic activity.During nutrient scarcity, intracellular amino acid levels decline. It results in the accumulation of uncharged tRNAs...
01:30Bacterial Signaling
Bacterial signaling can occur within bacteria (intracellular) or between bacteria (intercellular). At times, a group of bacteria behaves like a community. To achieve this, they engage in quorum sensing, the perception of higher cell density that causes changes in gene expression. Quorum sensing involves both extracellular and intracellular signaling. The signaling cascade starts with a molecule called an autoinducer (AI). Individual bacteria produce AIs that move out of the bacterial cell...
01:26Bacterial Phylum Bacteroidota
The phylum Bacteroidota includes over 700 species classified into four primary orders: Bacteroidales, Cytophagales, Flavobacteriales, and Sphingobacteriales. These gram-negative, non-sporulating rods exhibit saccharolytic capabilities and can be aerobic or fermentative, encompassing obligate aerobes, facultative aerobes, and obligate anaerobes. Many species display gliding motility, though some are nonmotile or use flagella. The genus Bacteroides is well-studied due to its significant role in...
01:27Bacterial Phylum Firmicutes
Firmicutes is a diverse phylum of Gram-positive bacteria characterized by a low GC content in their genomes. This phylum includes organisms with monoderm or diderm cell envelopes, highlighting a complex evolutionary history. Firmicutes comprises several major orders, including Lactobacillales, Clostridiales, and Bacillales, which exhibit remarkable diversity in their morphology, metabolism, and ecological roles.The order Lactobacillales includes lactic acid bacteria, which are fermentative...
01:28Gene Regulation in Microbial Communities: Quorum Sensing
Quorum sensing is a mechanism of bacterial communication that enables coordinated gene expression in response to changes in population density. This facilitates collective behaviors that enhance survival, resource acquisition, and ecological adaptation. This process relies on small signaling molecules called autoinducers that accumulate as bacterial populations grow. When a critical threshold concentration of autoinducers is reached, bacterial cells collectively modify gene expression,...