Functional Roles of Aggregation-Promoting-Like Factor in Stress Tolerance and Adherence of Lactobacillus acidophilus NCFM
Open accessAbstract
Aggregation-promoting factors (Apf) are secreted proteins that have been associated with a diverse number of functional roles in lactobacilli, including self-aggregation, the bridging of conjugal pairs, coaggregation with other commensal or pathogenic bacteria, and maintenance of cell shape. In silico genome analysis of Lactobacillus acidophilus NCFM identified LBA0493 as a 696-bp apf gene that encodes a putative 21-kDa Apf protein. Transcriptional studies of NCFM during growth in milk showed apf to be one of the most highly upregulated genes in the genome. In the present study, reverse transcriptase-quantitative PCR (RT-QPCR) analysis revealed that the apf gene was highly induced during the stationary phase compared to that during the logarithmic phase. To investigate the functional role of Apf in NCFM, an Δ apf deletion mutant was constructed. The resulting Δ apf mutant, NCK2033, did not show a significant difference in cell morphology or growth compared to that of the NCFMΔ upp reference strain, NCK1909. The autoaggregation phenotype of NCK2033 in planktonic culture was unaffected. Additional phenotypic assays revealed that NCK2033 was more susceptible to treatments with oxgall bile and sodium dodecyl sulfate (SDS). Survival rates of NCK2033 decreased when stationary-phase cells were exposed to simulated small-intestinal and gastric juices. Furthermore, NCK2033 in the stationary phase showed a reduction of in vitro adherence to Caco-2 intestinal epithelial cells, mucin glycoproteins, and fibronectin. The data suggest that the Apf-like proteins may contribute to the survival of L. acidophilus during transit through the digestive tract and, potentially, participate in the interactions with the host intestinal mucosa.
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
The claims and statistics of this paper haven’t been checked yet.
Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
The apf gene is widely distributed throughout Lactobacillus species.
“Although there were no significant conserved domains found in this protein, the apf gene was widely distributed throughout Lactobacillus species [59].”
From EVALUATION OF ADHESIVE AND AGGREGATION PROPERTIES OF LACTIC ACID BACTERIA ISOLATED FROM DIFFERENT BIOTOPES (2025) · cites this paper as [59]
In the ‘In silico analysis of apf’ section (page not provided), the paper says Apf orthologs appear to occur only in the L. acidophilus group of lactobacilli, based on sequence searches. That is contrary to the claim that the apf gene is widely distributed throughout Lactobacillus species. (LLM, conf=0.88)
Checked by a reasoning model — may be wrong.
Experimental — accuracy not yet measuredAuto-aggregation is associated with enhanced colonization, inhibition of pathogenic infections and immunomodulation of the intestinal mucosa.
“Auto-aggregation is a desired property for probiotics which is associated with enhanced colonization, inhibition of pathogenic infections and immunomodulation of the intestinal mucosa [12, 13, 28, 43, 44].”
From Bistable auto-aggregation phenotype in Lactiplantibacillus plantarum emerges after cultivation in in vitro colonic microbiota (2021) · cites this paper as [28]
The Abstract describes aggregation as a desirable probiotic trait and says studies suggest roles in colonization and immunomodulation of colonic mucosa. It says aggregates may inhibit pathogenic bacteria from adhering to intestinal mucosa, but does not establish inhibition of pathogenic infections; the citing sentence is broader on that point. (LLM, conf=0.85)
Experimental — accuracy not yet measured
Self-check
Percentages, sums and reported differences re-computed from the paper’s own numbers.
The self-check needs the paper’s full text.
The citation lists haven’t been fetched yet
References 48 · Cited by 149
Research works printed but not linked: 1
- [29]Klaenhammer, T. R., and W. M. Russell. 2000. Species of the Lactobacillus acidophilus complex, p. 1151-1157. In R. K. Robinson, C. Batt, and P. D. Patel (ed.), Encyclopedia of food microbiology, vol. 2. Academic Press, San Diego, CA.
- Authors
- Goh, Y. J., & Klaenhammer, T. R.
- Affiliations
- North Carolina State University (US)
- Corresponding author
- Klaenhammer, Todd R.
- ORCID
- Goh, Yong Jun
- Venue
- Applied and Environmental Microbiology
- Publisher
- American Society for Microbiology
- Published
- 2010-08
- Volume
- 76
- Issue
- 15
- Pages
- 5005-5012
- ISSN
- 0099-2240 (ISSN-L)
- 1098-5336
- PMC
- PMC2916482
- OpenAlex
- W2169475533
- Cited by
- 149
- References
- 48
- Citations by year
- 2026: 3 · 2025: 5 · 2024: 11 · 2023: 13 · 2022: 9 · 2021: 14 · 2020: 12 · 2019: 7 · 2018: 12 · 2017: 8 · 2016: 8 · 2015: 11 · 2014: 9 · 2013: 9 · 2012: 9
- FWCI
- 13.25
- Type
- journal article
- Language
- en
- Open access
- green
- www.ncbi.nlm.nih.gov
- Locations
- Applied and Environmental Microbiology (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Funders
- Dairy Management
- Topics
- Life Sciences › Agricultural and Biological Sciences › Food Science › Probiotics and Fermented Foods
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Bacterial Genetics and Biotechnology
- Life Sciences › Immunology and Microbiology › Microbiology › Reproductive tract infections research
- Keywords
- Lactobacillus acidophilus NCFM, stress tolerance, bacterial adhesion, bile tolerance, stationary phase gene expression, self-aggregation, mucin glycoproteins, fibronectin, probiotic viability
- MeSH terms
- Anti-Bacterial Agents, Bacterial Adhesion, Bile, Detergents, Epithelial Cells, Fibronectins, Gastric Juice, Lactobacillus acidophilus, Molecular Weight, Mucins, Phylogeny, Protein Binding, Sodium Dodecyl Sulfate, Gene Deletion, Sequence Homology, Amino Acid, Adhesins, Bacterial, Reverse Transcriptase Polymerase Chain Reaction, Gene Expression Profiling, Microbial Viability
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
