Biology subjects

Guimaraes, A. M. S.

Publications and source records attributed to Guimaraes, A. M. S..

2 recordsLinked to original sources

bioRxiv2025

Discrimination between Mycobacterium tuberculosis and Mycobacterium bovis using Fourier Transform Infrared Spectroscopy

Zoonotic tuberculosis (TB) caused by Mycobacterium bovis (Mb) is a neglected disease that hinders efforts to eradicate human tuberculosis. Developing a rapid, high-throughput diagnostic test to distinguish Mb from Mycobacterium tuberculosis (Mtb) isolates could enhance global zoonotic TB diagnostics and surveillance. This study aimed to evaluate the ability of Fourier Transform Infrared Spectroscopy (FT-IRS), using the IR Biotyper(R) system, to differentiate clinical isolates of Mb and Mtb. Two bacterial inactivation protocols-- paraformaldehyde and boiling--were tested using Mtb and BCG strains grown in liquid culture. While both methods allowed FT-IRS analysis, boiling was preferred due to its ease of use and efficiency in biomass recovery. Subsequently, Mtb and Mb isolates were analyzed using FT-IRS, and the resulting spectra were used to construct a sample classifier employing machine learning algorithms. Linear Discriminant Analysis (LDA) and a UPGMA dendrogram demonstrated clear separations between Mtb and Mb ecotypes. Additionally, a classifier built and internally validated using artificial neural networks achieved 99% accuracy in distinguishing Mb and Mtb. Further FT-IRS analysis of few available Mycobacterium africanum (Maf) strains demonstrated its capacity to differentiate Maf from Mtb and Mb, expanding its utility in regions where Maf is endemic. This is the first study to apply FT-IRS to distinguish tuberculous mycobacteria. FT-IRS proved to be a highly effective, rapid, and accurate diagnostic tool for differentiating Mb and Mtb strains, with promising applications for other tuberculous mycobacteria such as Maf. IMPORTANCEZoonotic tuberculosis (TB) caused by Mycobacterium bovis (Mb) remains a major threat due to its clinical similarity to human TB, higher rates of extrapulmonary cases, and resistance to pyrazinamide, complicating treatment. Current diagnostic methods used to differentiate M. tuberculosis (Mtb) from Mb and are limited by costs, resource needs, and technical complexity. We developed a method based on Fourier Transform Infrared Spectroscopy (FT-IRS) to differentiate Mb and Mtb clinical isolates with high accuracy. This diagnostic assay offers advantages over traditional molecular techniques by eliminating the need for DNA extraction, requiring less technical expertise, and providing fast, accurate differentiation of Mtb and Mb strains. This innovative approach can improve global diagnostics and surveillance of zoonotic TB.

microbiology↗

bioRxiv2021

SARS-CoV-2 Infection Impacts Carbon Metabolism and Depends on Glutamine for Replication in Syrian Hamster Astrocytes

Coronaviruses belong to a well-known family of enveloped RNA viruses and are the causative agent of the common cold. Although the seasonal coronaviruses do not pose a threat to human life, three members of this family, i.e., SARS-CoV, MERS-CoV and recently, SARS-CoV2, may cause severe acute respiratory syndrome and lead to death. Unfortunately, COVID-19 has already caused more than 4.4 million deaths worldwide. Although much is better understood about the immunopathogenesis of the lung disease, important information about systemic disease is still missing, mainly concerning neurological parameters. In this context, we sought to evaluate immunometabolic changes using in vitro and in vivo models of hamsters infected with SARS-CoV-2. Here we show that, besides infecting hamsters astrocytes, SARS-CoV-2 induces changes in protein expression and metabolic pathways involved in carbon metabolism, glycolysis, mitochondrial respiration, and synaptic transmission. Interestingly, many of the differentially expressed proteins are concurrent with proteins that correlate with neurological diseases, such as Parkinsonss disease, multiple sclerosis, amyotrophic lateral sclerosis, and Huntingtons disease. Metabolic analysis by high resolution real-time respirometry evidenced hyperactivation of glycolysis and mitochondrial respiration. Further metabolomics analysis confirmed the consumption of many metabolites, including glucose, pyruvate, glutamine, and alpha ketoglutarate. Interestingly, we observed that glutamine was significantly reduced in infected cultures, and the blockade of mitochondrial glutaminolysis significantly reduced viral replication and pro-inflammatory response. SARS-CoV-2 was confirmed in vivo as hippocampus, cortex, and olfactory bulb of intranasally infected hamsters were positive for viral genome several days post-infection. Altogether, our data reveals important changes in overall protein expression, mostly of those related to carbon metabolism and energy generation, causing an imbalance in important metabolic molecules and neurotransmitters. This may suggest that some of the neurological features observed during COVID-19, as memory and cognitive impairment, may rely on altered energetic profile of brain cells, as well as an unbalanced glutamine/glutamate levels, whose importance for adequate brain function is unquestionable.

immunology↗