Biology subjects

Machado, C. R.

Publications and source records attributed to Machado, C. R..

3 recordsLinked to original sources

bioRxiv2025

The peptide LyeTx I mnΔK induces transcriptomic reprogramming in a novel Multidrug-resistant Acinetobacter baumannii

Acinetobacter baumannii is a critical pathogen in healthcare-associated infections, and treatment is challenging due to the emergence of multidrug-resistant strains. Antimicrobial peptides, such as LyeTx I mn{Delta}K, a synthetic peptide derived of a toxin from the spider Lycosa erythrognatha, represent a promising alternative due to their broad-spectrum activity and synergistic potential with antibiotics like meropenem. This study aimed to compare the genomes of several A. baumannii strains, including a novel multidrug-resistant A. baumannii isolate (AC37), and to evaluate the antimicrobial effects of LyeTx I mn{Delta}K-alone and in combination with meropenem-through transcriptomic analysis. Genome assembly and annotation of AC37 revealed 31 antibiotic resistance genes, and phylogenetic analysis comprising 123 A. baumannii genomes, including the reference strain, identified three unique resistant genes in the AC37 strain. Mobilome analysis showed 13 genes associated with mobile genetic elements, including two of the unique genes, highlighting horizontal gene transfer events. Transcriptomic profiling revealed that treatment with LyeTx I mn{Delta}K peptide alone induced several differentially expressed genes, including two efflux pump operons. Additionally, pathways related to protein synthesis, export, and secretion were activated, indicating a broader cellular response to the peptide. The treatment with LyeTx I mn{Delta}K in combination with meropenem disrupted oxidative phosphorylation, further revealing the metabolic plasticity of the bacterial response to external stresses. This study characterizes a new A. baumannii isolate and provides new insights into the bacterial response to a potential novel therapeutic molecule.

bioinformatics↗

bioRxiv2025

The role of the Trypanosoma cruzi enzyme L-threonine 3-dehydrogenase in combating stressful environments

Trypanosoma cruzi is a digenetic parasite that undergoes various transformations to complete its life cycle. Changes between hosts and vectors involve exposure to stressful environments, for which it has developed different strategies to cope with such stress. L-threonine 3-dehydrogenase (TDH) is a key enzyme in trypanosome metabolism, and several studies have shown that inhibiting TDH affects parasite survival. To understand the role of TDH in T. cruzi, we investigated its expression in different benznidazole (Bz)-resistant clones and overexpressed it in a Bz-susceptible clone. After overexpressing TDH and exposing it to reactive oxygen species (ROS), alkylating agents, and drugs such as Bz, we evaluated certain biological parameters. Our results show that TDH led to higher survival rates when exposed to H2O2 and increased tolerance to Bz. Moreover, the parasites were able to infect more cells, and their mitochondrial membrane potential ({Psi}m) remained unchanged, both of which are linked to higher tolerance to ROS. Finally, parasites overexpressing TDH were less vulnerable to genetic damage caused by agents such as MMS and gamma radiation. Overall, our results demonstrate that TDH, a key enzyme in threonine metabolism, helps combat stressful environments and, under certain experimental conditions, supports the survival of parasites.

molecular biology↗

bioRxiv2019

Differential modulation of mouse heart gene expression by infection with two Trypanosoma cruzi strains: a transcriptome analysis

The protozoan Trypanosoma cruzi (T. cruzi) is a well-adapted parasite to mammalian hosts and the pathogen of Chagas disease in humans. As both host and T. cruzi are highly genetically diverse, many variables come into play during infection, making disease outcomes difficult to predict. One important challenge in the field of Chagas disease research is determining the main factors leading to parasite establishment in the chronic stage in some organs, mainly the heart and/or digestive system. Our group previously showed that distinct strains of T. cruzi (JG and Col1.7G2) acquired differential tissue distribution in the chronic stage in dually-infected BALB/c mice. To investigate changes in the host triggered by the two distinct T. cruzi strains, we assessed the gene expression profile of BALB/c mouse hearts infected with either JG, Col1.7G2 or an equivalent mixture of both parasites during the initial phase of infection. This study demonstrates a clear distinction in host gene expression modulation by both parasites. Col1.7G2 strongly activated Th1-polarized immune signature genes, whereas JG showed only minor activation of the host immune response. Moreover, JG strongly reduced the expression of genes for ribosomal proteins and mitochondrial proteins related to the electron transport chain. Interestingly, evaluation of gene expression in mice inoculated with the mixture of parasites showed expression profiles for both up- and down-regulated genes, indicating the coexistence of both parasite strains in the heart during the acute phase. This study suggests that different strains of T. cruzi may be distinguished by their efficiency in activating the immune system, modulating host energy and reactive oxygen species production and decreasing protein synthesis during early infection, which may be crucial in defining parasite persistence in specific organs.\n\nAuthor SummaryThe causative agent of Chagas disease, Trypanosoma cruzi, retains high genetic diversity, and its populations vary greatly across geographic locations. The T. cruzi mammalian hosts, including humans, also have high genetic variation, making it difficult to predict the disease outcome. Accordingly, this variability must be taken into account in several studies aiming to interrogate the effect of polyparasitism in drug trials, vaccines, diagnosis or basic research. Therefore, there is a growing need to consider the interaction between the pathogen and the host immune system in mixed infections. In the present work, we present an in-depth analysis of the gene expression of hearts from BALB/c mice infected with Col1.7G2 and JG alone or a mixture of both strains. Col1.7G2 induced a higher Th1 inflammatory response, while JG exhibited a weaker activation of immune response genes. Furthermore, JG-infected mice showed a notable reduction in the expression of genes responsible for mitochondrial oxidative phosphorylation and protein synthesis. Interestingly, the mixture-infected group displayed changes in gene expression as caused by both strains. Overall, we provided new insights into the host-pathogen interaction in the context of single and dual infection, showing remarkable differences in host gene expression modulation by two T. cruzi strains.

bioinformatics↗