Biology subjects

Pinheiro, P. F.

Publications and source records attributed to Pinheiro, P. F..

3 recordsLinked to original sources

bioRxiv2026

Omics analysis of MRSA under antibiotic stress identifies conserved adaptive modules and candidate adjuvant targets

Methicillin-resistant Staphylococcus aureus (MRSA) survives antibiotic exposure through coordinated physiological adaptation that extends beyond canonical resistance determinants. Here, we used an untargeted multi-omics strategy integrating proteomics, post-translational modifications, and metabolomics to characterize MRSA ATCC 43300 responses to five mechanistically distinct antibiotics: ampicillin, methicillin, vancomycin, chloramphenicol, and ciprofloxacin. Cells were exposed to 0.5x, 1x, and 2x IC50, enabling comparison of graded stress responses across antibiotic classes. Across treatments, MRSA did not deploy fully distinct drug-specific programs. Instead, antibiotic exposure repeatedly converged on a limited set of conserved adaptive modules detectable across independent molecular layers. These included coupling of envelope stress with genome maintenance, recurrent remodeling of metal/cofactor and redox homeostasis, sustained pressure on nucleotide and folate metabolism, and reprogramming of transport and surface-associated functions. A particularly robust cross-antibiotic signature was the accumulation of MoO2-molybdopterin cofactor. Ciprofloxacin additionally induced compensatory envelope reinforcement, supporting tight coupling between DNA damage responses and cell-envelope maintenance. Overall, the data support a unified model in which MRSA buffers mechanistically distinct antibiotic stress through a compact set of conserved stress-response functions rather than through entirely separate adaptive programs. These recurrent modules highlight candidate adjuvant vulnerabilities, particularly in metal/cofactor handling, nucleotide supply and repair, and transport/envelope compensation pathways. As this was an exploratory design intended to identify candidate adaptive patterns, these vulnerabilities now require validation in biologically replicated cultures and targeted functional studies.

microbiology↗

bioRxiv2023

Optimization of somatic embryogenesis in Euterpe edulis Martius using auxin analogs and atomic force microscopy

Euterpe edulis Martius is an endangered species of the Atlantic Forest, whose fruits have high antioxidant potential, and propagated exclusively by seeds. The present study assessed the ability of different auxin inducers and picloram analogs to trigger somatic embryogenesis in E. edulis. Immature seeds were harvested, and their zygotic embryos were excised and grown in MS culture medium supplemented with 2,4-D dichlorophenoxyacetic acid (2,4-D) or picloram at 150, 300, 450, 600 {micro}M. The activity of picloram analogs triclopyr and clopyralid was evaluated in semisolid MS medium. At maturation and germination, picloram-derived calli and somatic embryos isolated from triclopyr-grown cultures were first transferred to pre-maturation medium and, after 30 days, to basal MS or MS medium supplemented with either 5 {micro}M abscisic acid or 0.53 {micro}M 1-naphthaleneacetic acid plus 12.3 {micro}M 2-isopentenyladenine. Finally, somatic embryos with root protrusions were transferred to MS medium devoid of sucrose for 30 days and then acclimatized ex vitro. Scanning, transmission, and atomic force microscopy revealed that picloram was superior to 2,4-D but less effective than triclopyr (100 {micro}M) in inducing embryogenesis. Maturation and germination of somatic embryos in E. edulis can be maximized by 5 {micro}M abscisic acid, and selecting calli via atomic force microscopy. HighlightThis work opens novel roads for embryogenic induction, using a new and more efficient inducer than the usual ones, and an innovative evaluation technique based on AFM.

plant biology↗

bioRxiv2020

In vivo and in vitro mechanistic characterization of a clinically relevant PolγA mutation

Mutations in POLG, encoding POL{gamma}A, the catalytic subunit of the mitochondrial DNA polymerase, cause a spectrum of disorders characterized by mtDNA instability. However, the molecular pathogenesis of POLG-related diseases is poorly understood and efficient treatments are missing. Here, we generated a POLGA449T/A449T mouse model, which reproduces the most common human recessive mutation of POLG, encoding the A467T change, and dissected the mechanisms underlying pathogenicity. We show that the A449T mutation impairs DNA binding and mtDNA synthesis activities of POL{gamma} in vivo and in vitro. Interestingly, the A467T mutation also strongly impairs interactions with POL{gamma}B, the homodimeric accessory subunit of holo-POL{gamma}. This allows the free POL{gamma}A to become a substrate for LONP1 protease degradation, leading to dramatically reduced levels of POL{gamma}A, which in turn exacerbates the molecular phenotypes of PolgA449T/A449T mice. Importantly, we validated this mechanism for other mutations affecting the interaction between the two POL{gamma} subunits. We suggest that LONP1 dependent degradation of POL{gamma}A can be exploited as a target for the development of future therapies.

genetics↗