Biology subjects

Chamorro-Rodriguez, S.

Publications and source records attributed to Chamorro-Rodriguez, S..

3 recordsLinked to original sources

bioRxiv2026

3D printed titanium anodized effects on human gingival fibroblasts response and bacterial colonization: a dual approach

Mucointegration is as important as osseointegration to ensure the survival of implant-supported prosthesis. Indeed, effective soft tissue integration (STI) prevents the appearance of complication through bacterial dissemination. To optimize STI, electrochemical anodization can be used to nanostructure the trans-gingival part of the prosthetic component. Moreover, Selective Laser Melting (SLM) is a new 3D-manufacturing technique that enables the production of customized implant-supported prosthesis with complex geometry. ObjectiveThe aim of this study is to evaluate the effect of a SLM manufactured and anodized Ti6Al4V surface on the behaviour of both, human gingival fibroblasts and oral bacteria. MethodSLM-Ti6Al4V discs were polished and anodized with defined parameters to obtain nanotubes (NTs) with specific morphology. Surface characterization was assessed through surface topography and wettability. Human gingival Fibroblasts were cultured, and cell morphology was observed by SEM at day 7. Proliferation, viability (day 1,4,7) and adhesion (6 h and 36 h) were analyzed. Then immunofluorescence and RT-qPCR were used to detect the distribution and the gene expression of vinculin at 48 h. An early colonizer (Streptococcus gordonii) was used for a parallel evaluation of bacteriological adhesion. ResultsSLM-ANO-Ti6Al4V showed similar performances in terms of cytotoxicity, compared with a machined and polished titanium surface currently used in clinics. Interestingly, cell adhesion was enhanced on anodized SLM surfaces, with a difference in the distribution of focal adhesion plaques in HGFs, while biofilm formation of S. gordonii was not affected by anodization. SignificanceSLM anodized surface showed promising ability to promote STI while controlling bacterial adhesion.

biophysics↗

bioRxiv2026

Global analysis of trimeric autotransporters reveals phylogenetically restricted secretion mechanism adaptations

Autotransporters are important diderm bacterial cell-surface proteins and are virulence factors enabling surface attachment and adhesion to other bacteria. These proteins are composed of a signal peptide, a {beta}-barrel that serves as an anchor in the outer membrane, and an extracellular passenger domain responsible for adhesion. Autotransporters rely on BamA for their insertion in the outer membrane (OM), but specific helper proteins, such as TpgA and SadB have been described to promote the surface exposure of trimeric autotransporters (TAAs), a specialized subclass of autotransporters forming homotrimer adhesins. To identify domains or proteins that could help TAAs secretion, we analyzed a recent dataset of all trimeric autotransporters found across the bacterial tree of life. While we did not find additional potential helper proteins for OM translocation, we found that the extended signal peptide (ESPR), sometimes found in TAAs, is associated with longer adhesins both for TAAs and type Va autotransporter adhesins. ESPRs are found in all bacteria but Fusobacteriia and Alphaproteobacteria. We also identified in Burkholderia, Veillonellales and Pasteurellales a DUF2827 domain proteins as potential glycosyltransferases constantly associated with TAAs. Finally, e describe the existence of extra periplasmic domains in some TAAs, featuring either a coiled-coil domain or a peptidoglycan-binding domain. Our research show that there is a strong phylogenetic separation between Terrabacteria, almost invariably displaying additional periplasmic domains, and Gracilicutes (represented by Proteobacteria) where they are largely absent. This suggests that the presence these domains might be correlated with specific Terrabacteria OM features. Using the diderm Firmicute Veillonella parvula as a model, we demonstrate that the absence of periplasmic domains in TAAs leads to a significant protein degradation, yet they are not essential for adhesin trimerization or secretion. Additionnaly, we show that the SLH domains of V. parvula TAAs excludes them from the septum during division, but that this exclusion is not crucial for adhesin function or stability in the tested conditions. Altogether, these results illuminate the genetic flexibility and modularity of autotransporters, enhancing our understanding of this important class of adhesins in diderm bacteria.

microbiology↗

bioRxiv2024

Clostridioides difficile binary toxin CDT induces biofilm-like persisting microcolonies

Clinical symptoms of Clostridioides difficile infection (CDI) range from diarrhea to pseudomembranous colitis. A major challenge in managing CDI is the high rate of relapse. Several studies correlate production of CDT binary toxin by clinical strains of Clostridioides difficile with higher relapse rates. Although the mechanism of action of CDT on host cells is known, its exact contribution to CDI is still unclear. To understand the physiological role of CDT during CDI, we established two hypoxic relevant intestinal models, Transwell and Microfluidic Intestine-on-Chip systems. Both were challenged with the epidemic strain UK1 CDT+ and its isogenic CDT- mutant. We report that CDT binary toxin induces mucin-associated microcolonies that increase C. difficile colonization and display biofilm-like properties by enhancing C. difficile resistance to vancomycin but not to fidaxomicin, a biofilm disrupting antibiotic. Importantly, biofilm- like CDT-dependent microcolonies were also observed in the caecum and colon of infected mice. Hence, our study shows that CDT toxin induces biofilm-like microcolonies, increasing C. difficile colonization and persistence.

microbiology↗