Biology subjects

Martini, F.

Publications and source records attributed to Martini, F..

7 recordsLinked to original sources

bioRxiv2026

Fourier transform infrared spectroscopy reveals high intraspecies diversity of Malassezia pachydermatis in dogs with atopic dermatitis

1Canine atopic dermatitis (CAD) is a chronic inflammatory skin condition sometimes associated with microbial dysbiosis, including alterations in colonization by the lipophilic yeast Malassezia pachydermatis. This study investigated the population diversity of M. pachydermatis in the ear canals of healthy and CAD-affected dogs using Fourier-transform infrared (FTIR) spectroscopy and whole genome sequencing (WGS). Among 60 dogs, M. pachydermatis prevalence was significantly higher in CAD cases than in healthy controls. FTIR spectroscopy revealed greater strain heterogeneity in CAD-affected dogs, often with distinct genotypes in each ear, while healthy dogs exhibited more homogeneous populations. Using a previously developed FTIR-based artificial neural network classifier, we assigned strains to three phylogroups. Strains from phylogroups I and III were significantly enriched in CAD-affected dogs, while phylogroup II was most prevalent overall and the dominant phylogroup in healthy controls. This suggests that CAD-associated inflammation may favor specific M. pachydermatis phylogroups and sub-clusters within phylogroups, shaping colonization dynamics. FTIR-based typing showed full concordance with WGS across 35 sequenced isolates, recapitulating relationships among phylogenetically related isolates and their similar phenotypic profiles. Overall, our findings reveal strain-level shifts in M. pachydermatis populations associated with CAD and establish FTIR spectroscopy as a rapid, cost-effective tool for large-scale epidemiological studies.

microbiology↗

bioRxiv2026

Dexamethasone-induced PPARG expression in osteogenic differentiation in vitro: impact on SOX9 and RUNX2 levels.

BackgroundThe effects of dexamethasone during in vitro human osteogenesis present a complex picture. On one side, dexamethasone promotes the osteogenic differentiation of human bone marrow mesenchymal stromal cells (BMSCs) by downregulating SOX9. On the other side, it simultaneously promotes adipogenesis through the upregulation of PPARG. The regulation of SOX9 and PPARG levels appears to be mediated by the transactivation function of the glucocorticoid receptor (GR), suggesting an indirect effect of dexamethasone on SOX9 downregulation. This study aims to determine whether PPAR-{gamma} affects the expression levels of SOX9, as suggested by several studies. MethodsHuman BMSCs were isolated from bone marrow and cultured in different osteogenic induction media containing 10 or 100 nM dexamethasone. Undifferentiated cells were used as control. Cells were treated either with a pharmacological PPAR-{gamma} inhibitor (T0070907) or with a PPARG-targeting siRNA. Differentiation markers or PPAR-{gamma} target genes were analysed by RT-qPCR. Mineral deposition was assessed by Alizarin Red staining. Two-way ANOVA followed by a Sidak multiple comparison test was used to compare the effects of treatments. ResultsPharmacological inhibition of PPAR-{gamma} had a mild effect on the expression of PPAR-{gamma} target genes but hindered adipocyte formation. Neither RUNX2 nor SOX9 expression were affected by T0070907. siRNA treatment successfully downregulated PPARG expression, as well as that of PPAR-{gamma} target genes LPL, LPAR1, and ADIPOQ. Contrary to expectations, RUNX2 was significantly downregulated by the PPARG-siRNA treatment during osteogenic differentiation both in the absence and presence of dexamethasone, while SOX9 levels were downregulated in undifferentiated cells. Overall, Alizarin Red staining analysis showed no change in mineralization levels when PPARG expression or activity was inhibited. ConclusionsUnderstanding how dexamethasone regulates human BMSC differentiation is crucial to refine current in vitro models. These results suggest that PPAR-{gamma} is not involved in SOX9 or RUNX2 repression during in vitro osteogenic differentiation of human cells.

cell biology↗

bioRxiv2025

Combinatorial Cell-Adhesion and Activity Codes Instruct Cortical Modality Identity

The emergence of functional sensory modalities requires precise cortical arealization and appropriate thalamocortical targeting. Although early morphogen gradients set broad cortical territories, the mechanisms that specify sensory identity and guide modality-specific thalamocortical targeting remain unknown. Here, we identify an embryonic set of activity-independent cortical "protogenes", prominently enriched for cell-adhesion molecules, that are differentially expressed between primary somatosensory (S1) and visual (V1) cortices prior to thalamic innervation. These adhesion programs are selectively localized to layer 4, the main thalamo-recipient layer, and strikingly mirror the adhesion profiles of their corresponding thalamic nuclei, suggesting partner recognition. Disrupting thalamic activity alters modality-specific spontaneous cortical dynamics and the postnatal expression of another set of modality-specific genes, indicating a modulatory role for thalamic activity in cortical identity. These findings support a two-step model in which cortical identity is primed by adhesion codes driving modality-specific thalamocortical targeting, and later refined by patterned thalamic activity to establish functional cortical modalities.

neuroscience↗

bioRxiv2023

Transient Aurein 1.2 pores in prokaryotic model bilayers explored by coarse-grain molecular dynamics simulations: as glycolipid content increases, pore lifetime decreases.

The Aurein 1.2 is an anuran antimicrobial peptide (AMP) with a proven lytical activity against bacterial membranes. Previously, we found a differential action of aurein by both experimental and computational methods. This differential action was over membranes of two related probiotic strains, where the main differences between membranes were the number of glycolipids on lipid composition. In the present work, we focused on the differential behavior of the aurein 1.2 at its interaction with bacterium model membranes with different amounts of glycolipids in their composition. We carried out extensive molecular dynamics (MD) simulations by using the coarse-grain force field MARTINI and raising up differential mixtures of phosphatidylglycerol (PG), phosphatidylethanolamine (PE) and monogalactosylglycerol (MG). We found a correlation between the presence of MG in PG/PE mixtures and the difficulty of aurein to stabilize pore structures, suggesting an AMPresistance factor encoded in the lipid composition of the membrane. Through this study, we hope to shed light on a possible resistance mechanism to AMPs related with the glycolipid content of diverse types of bacterial membranes.

biophysics↗

bioRxiv2021

Genomic ancestry, diet and microbiomes of Upper Palaeolithic hunter-gatherers from San Teodoro cave (Sicily, Italy)

Recent improvements in the analysis of ancient biomolecules from human remains and associated dental calculus have provided new insights into the prehistoric diet and past genetic diversity of our species. Here we present a "multi-omics" study, integrating genomic and proteomic analyses of two post-Last Glacial Maximum (LGM) individuals from San Teodoro cave (Italy), to reconstruct their lifestyle and the post-LGM resettlement of Europe. Our analyses show genetic homogeneity in Sicily during the Palaeolithic, representing a hitherto unknown Italian genetic lineage within the previously identified "Villabruna cluster". We argue that this lineage took refuge in Italy during the LGM, followed by a subsequent spread to central-western Europe. Multi-omics analysis of dental calculus showed a diet rich of animal proteins which is also reflected on the oral microbiome composition. Our results demonstrate the power of using a multi-omics approach in the study of prehistoric human populations.

genetics↗

bioRxiv2020

Thalamic spontaneous activity coordinates the timing of corticothalamic innervation in the visual system

Sensory processing relies on the correct development of thalamocortical loops. Visual corticothalamic axons (CTAs) invade the dorsolateral geniculate nucleus (dLGN) of the thalamus in early postnatal mice according to a regulated program that includes activity-dependent mechanisms. Spontaneous retinal activity influences the thalamic incursion of CTAs, yet the perinatal thalamus also generates intrinsic patterns of spontaneous activity whose role in modulating afferent connectivity remains unknown. Here, we found that patterned spontaneous activity in the dLGN contributes to proper spatial and temporal innervation of CTAs. Disrupting patterned spontaneous activity in the dLGN delays corticogeniculate innervation under normal conditions and upon eye enucleation. The delayed innervation was evident throughout the first two postnatal weeks but resumes after eye-opening, suggesting that visual experience is necessary for the homeostatic recovery of corticogeniculate innervation.

neuroscience↗

bioRxiv2019

Late Upper Palaeolithic hunter-gatherers in the Central Mediterranean: new archaeological and genetic data from the Late Epigravettian burial Oriente C (Favignana, Sicily)

Grotta dOriente, a small coastal cave located on the island of Favignana (Sicily, Italy) is a key site for the study of the early human colonization of Sicily. The individual known as Oriente C was found in the lower portion of an anthropogenic deposit containing typical local Late Upper Palaeolithic (Late Epigravettian) stone assemblages. Two radiocarbon dates on charcoal from the deposit containing the burial are consistent with the archaeological context and refer Oriente C to a period spanning about 14,200-13,800 cal. BP. Anatomical features are close to those of Late Upper Palaeolithic populations of the Mediterranean and show strong affinity with Palaeolithic individuals of San Teodoro. Here we present new ancient DNA data from Oriente C. Our results, confirming previous genetic analysis, suggest a substantial genetic homogeneity among Late Epigravettian hunter-gatherer populations of Central Mediterranean, presumably as a consequence of continuous gene flow among different groups, or a range expansion following the Last Glacial Maximum (LGM).

genomics↗