Biology subjects

Romano, P.

Publications and source records attributed to Romano, P..

4 recordsLinked to original sources

bioRxiv2025

TcBDF6 deficiency compromises intracellular amastigotes development and infectivity in Trypanosoma cruzi

Trypanosoma cruzi, the causative agent of Chagas disease, relies on complex gene regulatory mechanisms to adapt to its diverse host environments. In recent years, it has been established that epigenetics plays an essential role in these mechanisms via the regulation of chromatin structure. Bromodomain-containing factors (BDFs), known for recognizing acetylated lysines on histones, have emerged as key factors in chromatin remodeling complexes. Among the eight predicted BDFs in T. cruzi, BDF6 is part of a TINTIN-like complex with MRGx and MRGBP, homologous to components of the NuA4/TIP60 chromatin remodeling complex. We generated knockout (KO) parasites for bdf6 gene using CRISPR/Cas9 gene editing. BDF6-deficient epimastigotes exhibit normal morphology but decreased size and growth and the resulting metacyclic trypomastigotes displayed drastically reduced infectivity. Strikingly, once inside host cells, BDF6-deficient parasites differentiated into amastigotes but failed to replicate. This intracellular arrest was reversed by episomal complementation of BDF6. Consistently, BDF6-KO parasites also exhibited impaired infectivity in mice, a defect that was also rescued in the add back parasite strains. Our findings highlight BDF6 as a critical regulator of intracellular parasite development, operating in stages beyond epimastigotes where epigenetic plasticity is essential for host adaptation. This striking stage-specific phenotype of BDF6 KO underscores its functional importance and highlights the relevance of epigenetic regulators along T. cruzis life cycle.

microbiology↗

bioRxiv2024

The energy-saving metabolic switch underlies survival of extremophilic red microalgae in extremely high nickel levels

The red microalga Cyanidioschyzon merolae inhabits extreme environments of high temperature (40-56{degrees}C), high acidity (pH 0.05-4), and the presence of high concentrations of heavy metals and sulphites that are lethal to most other forms of life. However, information is scarce on the precise adaptation mechanisms of this extremophile to such hostile conditions. Gaining such knowledge is important for understanding the evolution of microorganisms in the early stages of life on Earth characterized by such extreme environments. By analyzing the re-programming of the global transcriptome upon long-term (up to 15 days) exposure of C. merolae to extremely high concentrations of nickel (1 and 3 mM), the key adaptive metabolic pathways and associated molecular components were identified. Our work shows that long-term Ni exposure of C. merolae leads to the lagged metabolic switch demonstrated by the transcriptional upregulation of the metabolic pathways critical for cell survival. DNA replication, cell cycle, and protein quality control processes were upregulated while downregulation occurred of energetically costly processes including assembly of the photosynthetic apparatus and lipid biosynthesis. This study paves the way for the multi-omic studies of the molecular mechanisms of abiotic stress adaptation in phototrophs, as well as future development of the rational approaches for bioremediation of contaminated aquatic environments. ImportanceThis study provides the first comprehensive analysis of the global transcriptome re-programming in the extremophilic red microalga Cyanidioschyzon merolae during its long-term adaptation to heavy metals. We show that the lagged metabolic switch, demonstrated by the transcriptional upregulation of the metabolic pathways critical for cell survival, underlies the long-term Ni adaptation of this model extremophile. The transcriptomic results shed light on how life may have adapted to some of the harshest abiotic stresses on Earth including high temperatures, extreme acidity, and high levels heavy metals that are prohibitive to most other organisms. Additionally, the differentially regulated genes identified in this work provide important clues on the rational development of effective bioremediation strategies of removing heavy metals from the heavily contaminated aquatic environments.

plant biology↗

bioRxiv2021

Impact of Starmerella bacillaris and Zygosaccharomyces bailii on ethanol reduction and Saccharomyces cerevisiae metabolism during mixed wine fermentations

The bulk of grape juice fermentation is carried out by the yeast Saccharomyces cerevisiae, but non-Saccharomyces yeasts can modulate many sensorial aspects of the final products in ways not well understood. In this study, some of such non-conventional yeasts were screened as mixed starter cultures in a fermentation defined medium in both simultaneous and sequential inoculations. One strain of Starmerella bacillaris and another of Zygosaccharomyces bailii were chosen by their distinct phenotypic footprint and their ability to reduce ethanol levels at the end of fermentation, particularly during simultaneous vinification. S. bacillaris losses viability strongly at the end of mixed fermentation, while Z. bailii remains viable until the end of vinification. Interestingly, for most non-Saccharomyces yeasts, simultaneous inoculation helps for survival at the end of fermentation compared to sequential inoculation. S. cerevisiae viability was unchanged by the presence of the either yeast. Characterization of both strains indicates that S. bacillaris behavior is overall more different from S. cerevisiae than Z. bailii. S. bacillaris has a less strict glucose repression mechanism and molecular markers like catabolite repression kinase Snf1 is quite different in size. Besides, S. cerevisiae transcriptome changes to a bigger degree in the presence of S. bacillaris than when inoculated with Z. bailii. S. bacillaris induces the translation machinery and repress vesicular transport. Both non-Saccharomyces yeast induce S. cerevisiae glycolytic genes, and that may be related to ethanol lowering, but there are specific aspects of carbon-related mechanisms between strains: Z. bailii presence increases the stress-related polysaccharides trehalose and glycogen while S. bacillaris induces gluconeogenesis genes.

microbiology↗

bioRxiv2020

In vitro effects on cellular shaping, contratility, cytoskeletal organization and mitochondrial activity in HL1 cells after different sounds stimulation. A qualitative pilot study and a theoretical physical model.

Convincing evidence has documented that mechanical vibrations profoundly affect the behaviour of different cell types and even the functions of different organs. Pressure waves such as those of sound could affect cytoskeletal molecules with coherent changes in their spatial organization and are conveyed to cellular nucleus via mechanotransduction. HL1 cells were grown and exposed to different sounds. Subsequently, cells were stained for phalloidin, beta-actin, alpha-tubulin, alpha-actinin-1 and MitoTracker(R) mitochondrial probe. The cells were analyzed with time-lapse and immunofluorescence/confocal microscopy. In this paper, we describe that different sound stimuli seem to influence the growth or death of HL1 cells, resulting in a different mitochondrial localization and expression of cytoskeletal proteins. Since the cellular behaviour seems to correlate with the meaning of the sound used, we speculate that it can be "understood" by the cells by virtue of the different sound waves geometric properties that we have photographed and filmed. A theoretical physical model is proposed to explain our preliminary results.

cell biology↗