Biology subjects

Stoner, M. R.

Publications and source records attributed to Stoner, M. R..

3 recordsLinked to original sources

bioRxiv2026

Maternal vaccination timing shapes the composition and maturation of antibody clonotypes transferred to the newborn

Newborns rely on maternally transferred antibodies for immune protection, acquired across the placenta and through breast milk. Despite this importance, how closely the inherited antibody repertoire resembles the mothers has not been examined at the clonotypic level. We combined BCR-Seq with proteomic Ig-Seq to track SARS-CoV-2-specific antibody clonotypes across maternal blood, cord blood, and breast milk from six mRNA-immunized pregnant individuals. Vaccination earlier in gestation generated more diverse peak IgG repertoires but greater contraction before delivery, yielding fewer transferred clonotypes. Vaccination later in gestation produced more restricted peak repertoires, but more clonotypes persisted to delivery and transferred to cord. Infant cord was enriched for persistent, highly somatically mutated, and intraclonally diverse IgG clonotypes, consistent with preferential transfer of affinity-matured antibodies. In contrast, breast milk IgA repertoires were largely distinct from systemic repertoires and underwent substantial remodeling despite stable antigen titers. These findings define molecular determinants of passive immunity shaped by vaccination timing relevant to optimizing maternal immunization.

immunology↗

bioRxiv2025

Changes in biophysical characteristics of YghA from E. coli due to variation in pH

YghA from E. coli has been reported to be involved in conferring tolerance against furan aldehyde inhibitors which are commonly generated in thermo-acidic pretreatment of lignocellulosic biomass. In this study we report the biophysical characterization of YghA from E. coli as a function of variation in pH. Fluorescence intensity of YghA increased by 2.5-fold in acidic pH as compared to circumneutral pH. In presence of the hydrophilic 8-anilinonaphthalene-1-sulfonic acid (ANS) dye, a 68 - 79.4-fold increase in fluorescence intensity at acidic pH was observed as compared to circumneutral pH, while at basic pH the increase was only 1 to 2-fold. Secondary structure analysis by circular dichroism signal at 222 and 208 nm suggests that the secondary structure of YghA is primarily composed of alpha-helix at pH 7 and the secondary structure is abruptly lost at pH 3 and lower. In agreement with these observations, MD simulations predicted greater structural variations at low pH when compared to neutral or high pH. Interface energy calculations using computational docking protocols suggested that YghA forms relatively more stable complex with NADH. The in silico pulling assay results also show that NADH is more preferred compared to NADPH. Molecular dynamics simulations also indicate that YghA is structurally unstable at acidic pH with significant variations in the root mean square deviation values of the tetramer backbone. Residues GLU 84 at pH 7 together with PRO 24 and LEU 236 at pH 1 were identified as flexible residues and are promising target for future mutagenesis studies targeted towards improving structural stability of YghA.

biochemistry↗

bioRxiv2022

Polyploidy, regular patterning of genome copies, and unusual control of DNA partitioning in the Lyme disease spirochete

Borrelia burgdorferi, the tick-transmitted spirochete agent of Lyme disease, has a highly segmented genome with a linear chromosome and various linear or circular plasmids. Here, by imaging several chromosomal loci and 16 distinct plasmids, we show that B. burgdorferi is polyploid during growth in culture and that the number of genome copies decreases during stationary phase. B. burgdorferi is also polyploid inside fed ticks and chromosome copies are regularly spaced along the spirochetes length in both growing cultures and ticks. This patterning involves the conserved DNA partitioning protein ParA whose localization is controlled by a potentially phage-derived protein, ParZ, instead of its usual partner ParB. ParZ binds its own coding region and acts as a centromere-binding protein. While ParA works with ParZ, ParB controls the localization of the condensin, SMC. Together, the ParA/ParZ and ParB/SMC pairs ensure faithful chromosome inheritance. Our findings underscore the plasticity of cellular functions, even those as fundamental as chromosome segregation.

microbiology↗