Biology subjects

Coelho, A. V.

Publications and source records attributed to Coelho, A. V..

4 recordsLinked to original sources

bioRxiv2025

Lauric acid: a promising antimicrobial for the selective inhibition of Staphylococcus epidermidis strains associated with infection

Staphylococcus epidermidis, a human skin colonizer and opportunistic pathogen associated with medical device infections, comprises two phylogenetic lineages: A/C (infection and colonization strains) and B (primarily colonization strains). Given the need for antibiotic alternatives, we investigated the antimicrobial activity of skin-derived fatty acids--lauric, palmitoleic, and linoleic acids--against representative strains from both lineages. Fatty acids reduced exponential growth rate and maximum population, with greater effects on the A/C strain. Lauric and palmitoleic acids decreased colony radius in the B strain. Importantly, lauric acid showed no cytotoxicity on a 3D reconstructed human epidermis model. Our findings demonstrate differential susceptibility between lineages, with A/C strains showing greater sensitivity to all tested fatty acids than B strains. These results highlight the potential of lauric acid as a topical formulation for selective inhibition of S. epidermidis growth, offering a promising approach for preventing pathogenic strain proliferation while preserving beneficial skin colonizers.

microbiology↗

bioRxiv2025

Dynamic exometabolomics reveals metabolic adaptations of Staphylococcus epidermidis to pH-mimicking skin and bloodstream

Staphylococcus epidermidis (SE) is a common human skin coloniser, which is often the cause of medical device-associated infections. SE population is composed of two clonal lineages, A/C and B, with distinct pathogenic potential. Although pH is known to change during infection when SE crosses the host skin to access the bloodstream, the impact of this pH alteration on SE pathogenicity is poorly understood. Recognizing how SE deals with pH increments will help designing effective prevention and treatment strategies against SE infections. To investigate the metabolic adaptations of representative A/C and B strains to different pH, we mimicked skin and blood pH conditions (5.5 and 7.4) and followed biomass formation, growth media pH and exometabolites over time. Although both strains share some metabolic patterns, specificities were identified for each strain and pH condition. The B strain was better adapted to use diverse carbon sources and at blood pH has a more active TCA cycle and amino acid catabolism. At blood pH, the B strain depletes formate from the extracellular media, while its extracellular accumulation by the A/C strain could work as a host invasion strategy. For both SE strains, TCA cycle regulation, purine biosynthesis and glutamate uptake could be associated with virulence, particularly biofilm production, especially relevant for ICE25 which is able to produce high adherence biofilm. The uptake and consumption of saccharides follow similar profiles and seem to be pH-regulated by both strains. The dynamic study of SE exometabolome has contributed to understanding the intracellular processes and their relationship with virulence.

microbiology↗

bioRxiv2022

Regeneration of Starfish Radial Nerve Cord restores animal mobility and unveils a new coelomocyte population

The potential to regenerate a damaged body part is expressed to a different extent in animals. Echinoderms, in particular starfish, are known for their outstanding potential to regenerate cell, tissue, organ, and body parts. For instance, humans have restricted abilities to restore organ systems being dependent on limited sources of stem cells. In particular, the potential to regenerate the central nervous system is extremely limited, explaining the lack of natural mechanisms that could overcome the development of neurodegenerative diseases and the presence of traumatisms. Therefore, understanding the molecular and cellular mechanisms of regeneration in starfish could lead to the development of new therapeutic approaches in humans. In this study, we tackle the problem of starfish central nervous system regeneration by examining anatomical and behavioral traits, including external anatomic anomalies, the dynamics of coelomocytes populations and neuronal tissue architecture. We noticed that several anatomic anomalies were evident and detected that the injured arm could not be used anymore to lead the starfish movement. Those seem to be related to defense mechanisms and protection of the wound. In particular, histology showed that tissue patterns during regeneration resemble those described in holothurians and in starfish arm tip regeneration. Flow cytometry coupled with imaging flow cytometry unveiled a new coelomocyte population during the late phase of the regeneration process. Morphotypes of previously characterized coelomocytes populations were described based on IFC data. Further studies of this new coelomocyte population might provide insights on their involvement in radial nerve cord regeneration.

zoology↗

bioRxiv2020

A combined characterization of coelomic fluid cell types in the spiny starfish Marthasterias glacialis: inputs from flow cytometry and imaging

Coelomocytes is a generic name for a collection of cellular morphotypes, present in many coelomate animals, that has been reported as highly variable across echinoderm classes. The roles attributed to the major types of the free circulating cells present in the coelomic fluid of echinoderms include immune response, phagocytic digestion and clotting. The main aim of the present study is the thorough characterization of coelomocytes present in the coelomic fluid of Marthasterias glacialis (class Asteroidea) through the combined use of flow cytometry (FC) and fluorescence plus transmission electron microscopy. Two coelomocyte populations (here named P1 and P2) were identified by flow cytometry and subsequently studied in terms of abundance, morphology, ultrastructure, cell viability and cell cycle profiles. Ultrastructurally, P2 diploid cells showed two main morphotypes, similar to phagocytes and vertebrate thrombocytes, whereas the small P1 haploid cellular population was characterized by a low mitotic activity, relatively undifferentiated cytotype and a high nucleus/cytoplasm ratio. These last cells resemble stem-cell types present in other animals. P1 and P2 cells differ also in cell viability and cell cycle profiles. Additionally, two other morphotypes were only detected by fluorescence microscopy and a third one when using a combined microscopy/FC approach.

cell biology↗