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result(s) for
"Matos, Gabriel M."
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Genetic coping mechanisms observed in Leishmania tropica, from the Middle East region, enhance the survival of the parasite after drug exposure
2024
Cutaneous leishmaniasis caused by L. tropica is common in the Middle East and treatment failure and drug resistance are known to occur. Several genetic mechanisms: aneuploidy, recombination and loss of heterozygosity, single nucleotide polymorphism (SNP) changes, copy number variation (CNV), and mutation of the H locus associated with drug resistance have been described.
We studied SNP and CNV patterns in 22 isolates of L. tropica from Afghanistan, Iran and Syria in a geographic, phylogenetic and antimony exposure context.
A high SNP frequency was observed in isolates from Syria on chromosome 23, including the H locus, linked to different ancestry at that chromosome segment. Among the isolates from Afghanistan and Iran, an elevated frequency of nonsynonymous SNPs was observed on several chromosomes. Changes in CNV patterns were seen in isolates exposed to drug pressure, especially for the ferric iron reductase gene. Expanded genes were categorised into five functional categories: translational elongation, mitochondrial transmembrane transport, positive regulation of cellular component organisation, response to stimulus and response to hypoxia. No CNV was identified at the H locus, the MAPK1 gene, the APQ1 gene, nor chromosomes 23, 31 or 36 regardless of previous antimonial exposure.
In our study, Leishmania tropica had a jump in the nonsynonymous SNP rates at chromosome 23, including the H locus. CNV was observed among isolates exposed to antimonials, especially involving the gene encoding a ferric iron reductase. Several essential genetic coping mechanisms in the cell were enhanced when exposed to antimony, possibly for the survival of the parasite. Our work supports the perspective that Leishmania uses several mechanisms to adapt to environmental changes and drug exposure.
Journal Article
Expression of Transient Receptor Potential Channel Genes and Their Isoforms in Alpha-Cells and Beta-Cells of Human Islets of Langerhans
2022
Expression of the transient receptor potential (TRP) channel genes and their isoforms in the alpha-cells and the beta-cells of the human islets of Langerhans has not been studied in detail. In this study, we have analyzed the RNA sequencing data obtained from purified human alpha-cells and beta-cells to identify the genes and their isoforms that are expressed differentially in these two cell types. We found that TRPC1, TRPC4, TRPC7, TRPM3, and TRPML1 were differentially expressed in these two cell types. TRPC1, TRPM3, and TRPML1 were expressed at a higher level in the beta-cells than in the alpha-cells. TRPC4 and TRPC7 were expressed at a higher level in the alpha-cells than in the beta-cells. The TRPC4-206 isoform was expressed at a 45-fold higher level in the alpha-cells compared to the beta-cells. Expression of TRPM3-202 was 200-fold and TRPM3-209 was 25-fold higher in the beta-cells than in the alpha-cells. Our study has demonstrated the relative abundance of expression of the TRP channel genes and their isoforms in the human alpha-cells and the beta-cells.
Journal Article
Experimental microevolution of Trypanosoma cruzi reveals hybridization and clonal mechanisms driving rapid diversification of genome sequence and structure
2021
Protozoa and fungi are known to have extraordinarily diverse mechanisms of genetic exchange. However, the presence and epidemiological relevance of genetic exchange in Trypanosoma cruzi, the agent of Chagas disease, has been controversial and debated for many years. Field studies have identified both predominantly clonal and sexually recombining natural populations. Two of six natural T. cruzi lineages (TcV and TcVI) show hybrid mosaicism, using analysis of single-gene locus markers. The formation of hybrid strains in vitro has been achieved and this provides a framework to study the mechanisms and adaptive significance of genetic exchange. Using whole genome sequencing of a set of experimental hybrids strains, we have confirmed that hybrid formation initially results in tetraploid parasites. The hybrid progeny showed novel mutations that were not attributable to either (diploid) parent showing an increase in amino acid changes. In long-term culture, up to 800 generations, there was progressive, gradual erosion of progeny genomes towards triploidy, yet retention of elevated copy number was observed at several core housekeeping loci. Our findings indicate hybrid formation by fusion of diploid T. cruzi, followed by sporadic genome erosion, but with substantial potential for adaptive evolution, as has been described as a genetic feature of other organisms, such as some fungi.
Discovering the allure of forests: Exploring adolescent queries in nature-rich environments
2025
This study explores adolescents’ inherent curiosity about nature through the production of self-generated questions during a field visit to a nature-rich environment, followed by descriptive-interpretative analysis using focus groups. Utilizing cultural probes and content-free question tokens, we collected 164 valid questions produced by 36 adolescents during the field session. Biotic elements, like species, turned out to be more intriguing than abiotic elements, originating 89.6% of the questions. The predominant topics were related to species adaptation, extinction, dispersion, and diversity, with younger adolescents showing a notable interest in nature conservation, while older adolescents highlighted biodiversity dynamics. These findings were corroborated by the ranking of the TOP-5 most interesting questions, where biodiversity dynamics, nature conservation and plant physiology occupied the same relative positions. Our results indicate that in a nature-rich environment and through an inquiry-based approach, adolescents were encouraged to express curiosity about nature. This approach could be a valuable educational strategy to enhance their connection to nature, promote conservation responsibility, and benefit the environment.
Journal Article
Numerical tests of the large charge expansion
by
Matos, José
,
Cuomo, Gabriel
,
Penedones, João
in
Algorithms
,
Classical and Quantum Gravitation
,
Conformal and W Symmetry
2024
A
bstract
We perform Monte-Carlo measurements of two and three-point functions of charged operators in the critical
O
(2) model in 3 dimensions. Our results are compatible with the predictions of the
large charge
superfluid effective field theory. To obtain reliable measurements for large values of the charge, we improved the Worm algorithm and devised a measurement scheme which mitigates the uncertainties due to lattice and finite size effects.
Journal Article
c-myc Regulates Cell Proliferation during Lens Development
by
Gomes, Anielle L.
,
Rodrigues, Paulo M. G.
,
Martins, Rodrigo A. P.
in
Animals
,
Apoptosis
,
Auditory defects
2014
Myc protooncogenes play important roles in the regulation of cell proliferation, growth, differentiation and survival during development. In various developing organs, c-myc has been shown to control the expression of cell cycle regulators and its misregulated expression is detected in many human tumors. Here, we show that c-myc gene (Myc) is highly expressed in developing mouse lens. Targeted deletion of c-myc gene from head surface ectoderm dramatically impaired ocular organogenesis, resulting in severe microphtalmia, defective anterior segment development, formation of a lens stalk and/or aphakia. In particular, lenses lacking c-myc presented thinner epithelial cell layer and growth impairment that was detectable soon after its inactivation. Defective development of c-myc-null lens was not caused by increased cell death of lens progenitor cells. Instead, c-myc loss reduced cell proliferation, what was associated with an ectopic expression of Prox1 and p27(Kip1) proteins within epithelial cells. Interestingly, a sharp decrease in the expression of the forkhead box transcription factor Foxe3 was also observed following c-myc inactivation. These data represent the first description of the physiological roles played by a Myc family member in mouse lens development. Our findings support the conclusion that c-myc regulates the proliferation of lens epithelial cells in vivo and may, directly or indirectly, modulate the expression of classical cell cycle regulators in developing mouse lens.
Journal Article
Development of a bench system with capacitive sensor, sample compression, and TinyML for iron ore moisture measurement
2025
In the mineral sector, many processes use water for ore beneficiation processes. A lack of sensing or control of water content can lead to operational problems in various mineral processing operations, especially in ore transport. Current instrumentation systems are either slow or inaccurate. Therefore, a novel bench system was developed to address this gap by achieving a fast response time and improved accuracy. The developed instrument measures the ore moisture by using the real-dual-frequency method (RDFM) to assess the ore’s electrical conductivity and relative permittivity. Additionally, it takes into account the bulk density, the bench chamber level, and the compress torque. All these variables are used to create a tiny machine-learning (TinyML) model that evaluates the ore’s moisture with a low time response. This process is done while the ore sample is compressed to reduce air bubbles inside the samples and improve measurement. Experiments were performed using the bench system in a mining company’s physical analysis laboratory. The instrument was utilized to measure the moisture content in the ore, leading to the development of a dataset used to train and validate various tree-based tinyML models. The results indicate that ore compression enhances accuracy and that decision trees are effective for estimating moisture with a quicker response time.
Journal Article
Solid Surface Vitrification Is Better than Slow Freezing for the Long-Term Preservation of Testicular Fragments from Prepubertal Collared Peccaries (Pecari tajacu Linnaeus, 1758)
by
Bezerra, Gabriel S. C.
,
Pereira, Ana G.
,
Pereira, Alexsandra F.
in
Animals
,
Biobanks
,
Biodiversity
2025
The cryopreservation of male gonadal tissue is critical to conserve genetic material and use it later via assisted reproduction. This study aimed to evaluate cryopreservation methods (slow freezing, SF; solid surface vitrification, SSV) as well as the optimal concentrations of intracellular cryoprotectants during the SSV of testicular tissue from prepubertal collared peccaries. Five pairs of testes were dissected on different days into small fragments (3 mm3) and allocated to a non-cryopreserved, a control group or one of three treatment groups: SF; SSV 3 M (1.5 M dimethyl sulfoxide [DMSO] plus 1.5 M ethylene glycol [EG]); or SSV 6 M (3 M DMSO plus 3 M EG). After one week of storage in liquid nitrogen, tissue samples were warmed and evaluated in terms of histology, viability, proliferative capacity potential, and DNA integrity. The scores for histological integrity and cellular damage for SF (2.08 ± 0.05 and 2.33 ± 0.07, respectively) were similar to the results found in SSV 6 M (1.93 ± 0.04 and 2.30 ± 0.07; p > 0.05). However, these scores were better when compared to SSV 3 M (1.87 ± 0.05 and 2.08 ± 0.06; p < 0.05). The percentage of cellular viability was around 57% after all preservation treatments (p > 0.05), which was lower than in the control group (88.8 ± 1.9%; p < 0.05). The SSV 6 M treatment was better than the other treatments regarding the proliferative capacity potential of spermatogonia cells (3.52 ± 0.03) (p < 0.05), although it was lower than in the control group (4.00 ± 0.12) (p < 0.05). Additionally, SSV 6 M led to the same DNA integrity (97.0 ± 0.7%) as in the control group (99.4 ± 0.3%). These collective findings suggest that the combination of SSV with 6 M cryoprotectants is the most efficient for the cryopreservation of testes from prepubertal collared peccaries.
Journal Article
Microevolution of Trypanosoma cruzi reveals hybridization and clonal mechanisms driving rapid genome diversification
by
Yeo, Matthew
,
Miles, Michael A
,
Matos, Gabriel Machado
in
Adaptiveness
,
Amino acid sequence
,
Chagas disease
2022
Protozoa and fungi are known to have extraordinarily diverse mechanisms of genetic exchange. However, the presence and epidemiological relevance of genetic exchange in Trypanosoma cruzi , the agent of Chagas disease, has been controversial and debated for many years. Field studies have identified both predominantly clonal and sexually recombining natural populations. Two of six natural T. cruzi lineages (TcV and TcVI) show hybrid mosaicism, using analysis of single-gene locus markers. The formation of hybrid strains in vitro has been achieved and this provides a framework to study the mechanisms and adaptive significance of genetic exchange. Using whole genome sequencing of a set of experimental hybrids strains, we have confirmed that hybrid formation initially results in tetraploid parasites. The hybrid progeny showed novel mutations that were not attributable to either (diploid) parent showing an increase in amino acid changes. In long-term culture, up to 800 generations, there was a variable but gradual erosion of progeny genomes towards triploidy, yet retention of elevated copy number was observed at several core housekeeping loci. Our findings indicate hybrid formation by fusion of diploid T. cruzi , followed by sporadic genome erosion, but with substantial potential for adaptive evolution, as has been described as a genetic feature of other organisms, such as some fungi.
Journal Article
Effect of Diluents and Storage Time on the Cryopreservation of Collared Peccary (Pecari tajacu) Semen after Cooling Storage in a Transport Container at 5 °C
2024
We verified the possibility of cooling peccary semen for 4, 24, and 48 h before cryopreservation, using different dilution media (TRIS + egg yolk (20%) and PRIMXcell Ultra). Ten ejaculates were divided equally into six aliquots and then diluted. Two aliquots were stored in a biological incubator (4 h), and the remaining aliquots were stored in a commercial container, the Botutainer® (24 and 48 h), both at 5 °C. The samples were cryopreserved and then evaluated for kinetic parameters, functionality, integrity, mitochondrial activity, morphology, and sperm binding capacity. After thawing, samples diluted in TRIS showed total motility of 43.4 ± 6.8%, 48.4 ± 6.2%, and 38.6 ± 5.0% after cooling for 4, 24, and 48 h before cryopreservation, respectively. Such results are significantly greater than those achieved with the use of PRIMXcell diluent for 4 (8.3 ± 2.8%), 24 (4.7 ± 1.4%), and 48 h (4.8 ± 2.9%) storage (p < 0.05). Furthermore, TRIS provided better preservation of sperm membrane integrity when samples were cooled for 24 h (44.5 ± 4.7%) before cryopreservation compared to those samples diluted in PRIMXcell Ultra stored for 24 (25.7 ± 4.0%) and 48 h (25.2 ± 4.0%) before freezing (p < 0.05). In summary, we suggest TRIS diluent + egg yolk (20%) as an effective option to allow semen to cool for 24 or 48 h in a transport container before cryopreservation.
Journal Article