Biology subjects

Schrader, S.

Publications and source records attributed to Schrader, S..

3 recordsLinked to original sources

bioRxiv2026

Archaeological preservation of amelogenesis pathways

Dental enamel, the hardest mineralised tissue in the human body, has proven to be an excellent source of ancient proteins, which have been found to survive within dental enamel for at least twenty million years. In archaeological and palaeontological contexts, the enamel proteome is generally considered to be rather small, consisting of about twelve proteins, most of which are unique to enamel. During amelogenesis these proteins undergo in vivo digestion by matrix metalloproteinase 20 (MMP20) and kallikrein 4 (KLK4) as well as serine phosphorylation by family with sequence similarity member 20-C (FAM20C) that alter their characteristics. Gaining knowledge of the previously understudied influence of amelogenesis on the archaeological human dental enamel proteome could benefit various palaeoproteomic analysis, especially in an human evolutionary context. Here we present archaeological dental enamel proteomes and explore protein cleavage patterns and sequence coverage to estimate the effects of in vivo digestion, as well as explore phosphorylation patterns. Additionally, we present a new marker based on phosphorylation to estimate genetic sex.

evolutionary biology↗

bioRxiv2025

Alanine dependence of trans-translation contributes to riboregulation of mycobacterial antibiotic recalcitrance genes

ASBTRACTAntibiotic recalcitrance refers to a slower rate of death for either a bacterial population or a subpopulation of cells upon antibiotic exposure. It complicates treatment of many bacterial infections by contributing to treatment length, treatment failure, disease recurrence, and the emergence of antimicrobial resistance (AMR). Thus, blocking antibiotic recalcitrance could be a powerful strategy for improving treatment outcomes and reducing AMR rates. Here, using a forward genetic method for the isolation of antibiotic-recalcitrant mutants, we isolated two Mycobacterium smegmatis strains with mutations in the tRNA-modifying enzyme adenine-N(1)-methyltransferase. Both mutants were recalcitrant to proteostasis-perturbing antibiotics. We linked these phenotypes to upregulation of the transcriptional regulator WhiB7, highlighting its role as a point of convergence in the regulation of multiple mechanisms of antibiotic recalcitrance and resistance. Further, we identified a mechanism by which the amino acid alanine couples trans-translation to ribosome regulation-dependent, WhiB7-mediated expression of antibiotic resistance and recalcitrance genes, allowing bacterial cells to engage seemingly mutually exclusive mechanisms of survival upon exposure to stress.

microbiology↗

bioRxiv2025

Composition variations in archaeological human bone proteomes

Sampling strategies within the field of skeletal palaeoproteomics are often based on specimen availability. Knowledge of bone biology might assist in improving sample selection strategies and minimise unnecessary sampling of precious (hominin) material. We study ten bone sample locations across four bone elements, for a total of 10 adult, archaeological human skeletons. We compare bone proteome composition and modification for skeletal elements formed through endochondral and intramembranous ossification, as well as cortical-trabecular bone pairs of three skeletal locations. We observe minimal differences in bones formed through the two ossification processes, outside of the exclusive presence of cartilage-related proteins in endochondral bone samples. We observe higher protein concentrations, a larger number of protein groups and peptides, and lower rates of deamidation in cortical bone compared to trabecular bone proteomes, this indicates that cortical bone provides a better preservation environment compared to trabecular bone. Throughout our analysis, the petrous bone stands out, with the largest and most complex proteomes recovered for all studied individuals. Formed through endochondral ossification, the petrous bone undergoes minimal turnover during life. Our observations indicate that the petrous bone is the ideal source of ancient protein sequence information.

evolutionary biology↗