# Sialic acid mediated interbacterial adhesion among oral bacteria

> **NIH NIH F32** · STATE UNIVERSITY OF NEW YORK AT BUFFALO · 2022 · $70,602

## Abstract

PROJECT SUMMARY/ABSTRACT
Glycan-mediated interbacterial coadhesion is a critical part of multispecies biofilm formation in the human mouth.
Certain strains of oral streptococci express serine-rich repeat protein (SRRP) adhesins that bind to sialic acids,
common terminal sugars expressed on human oral mucosal epithelia and glycosylated salivary proteins. Sialic
acids (Sias) are a group of nine-carbon sugars of which over fifty different subtypes exist. Streptococcal SRRPs
are genetically diverse among strains, which likely evolved to bind to the multitude of Sia subtypes. To determine
the full scope of diverse Sia-binding SRRP sequences encoded by streptococci, the applicant used hidden
Markov models designed to identify Sia-binding SRRPs among over six thousand publicly available streptococcal
genome sequences. The applicant identified hundreds of Sia-binding SRRP sequences, which likely reflect
binding specificities for different Sia subtypes. For example, several strains of oral streptococci preferentially
bind to either of the two Sia subtypes, N-acetylneuraminic acid (Neu5Ac) or N-glycolylneuraminic acid (Neu5Gc).
Certain strains of bacteria evolved to either de novo synthesize or scavenge Sias from the environment and
display them on their surface. Since Sia subtypes are diverse and since the applicant’s data show that
streptococcal Sia-binding SRRP sequences are equally diverse, we believe that specificity of Sia-subtype-
mediated streptococcal binding expands beyond the mere difference between Neu5Ac and Neu5Gc. Together,
these data served as the basis for the applicant to formulate his independent hypothesis that oral streptococci
bind to an assortment of Sia subtypes expressed by other oral bacteria. In this project, the applicant aims to
identify Sia-expressing oral bacteria that serve as coadhesion partners of Sia-binding oral streptococci. In
Aim 1, Sia-expressing oral bacteria will be identified by both an in-silico approach and isolated from human oral
biofilms, then tested for coadhesion with Sia-binding oral streptococci. In Aim 2, bacterial strains known to
express Sias as well as those newly identified strains in Aim 1 will be used to determine how different Sia
subtypes expressed by bacteria affect coadhesion. The results of this proposed investigation will demonstrate
how Sia subtypes influence glycan-mediated interbacterial coadhesion. Investigating the precise mechanism of
Sia subtype-mediated interbacterial binding will help to understand how members of the oral microbiome interact
to form potentially disease-associated microbial biofilms in the human oral cavity. The planned project will build
on Dr. Ahearn’s skills acquired during his PhD dissertation research in bioinformatic and experimental analysis
of bacterial surface-exposed components. In this project, he will expand his expertise into the emerging field of
microbial glycobiology. Data derived from this project will allow Dr. Ahearn to advance to the next stage of ...

## Key facts

- **NIH application ID:** 10607228
- **Project number:** 1F32DE031963-01A1
- **Recipient organization:** STATE UNIVERSITY OF NEW YORK AT BUFFALO
- **Principal Investigator:** Christian Ahearn
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $70,602
- **Award type:** 1
- **Project period:** 2022-12-01 → 2023-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10607228

## Citation

> US National Institutes of Health, RePORTER application 10607228, Sialic acid mediated interbacterial adhesion among oral bacteria (1F32DE031963-01A1). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10607228. Licensed CC0.

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