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result(s) for
"Martinez, Mario"
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Learning under social versus nonsocial uncertainty: A meta‐analytic approach
2022
Much of the uncertainty that clouds our understanding of the world springs from the covert values and intentions held by other people. Thus, it is plausible that specialized mechanisms that compute learning signals under uncertainty of exclusively social origin operate in the brain. To test this hypothesis, we scoured academic databases for neuroimaging studies involving learning under uncertainty, and performed a meta‐analysis of brain activation maps that compared learning in the face of social versus nonsocial uncertainty. Although most of the brain activations associated with learning error signals were shared between social and nonsocial conditions, we found some evidence for functional segregation of error signals of exclusively social origin during learning in limited regions of ventrolateral prefrontal cortex and insula. This suggests that most behavioral adaptations to navigate social environments are reused from frontal and subcortical areas processing generic value representation and learning, but that a specialized circuitry might have evolved in prefrontal regions to deal with social context representation and strategic action. Much of the uncertainty that clouds our understanding of the world is caused by other people's actions and values. So there could be specialized mechanisms that compute learning signals under uncertainty of exclusively social origin operate in the brain. Our results suggest that most, but not all, behavioral adaptations to navigate social environments are reused from generic value representation and updating mechanisms.
Journal Article
Drought as a driver of Mexico-US migration
2021
Emigration from Mexico to the USA represents one of the largest current socioeconomic phenomena in the world. Climate, and particularly drought, has been identified as a key driver of peak migratory flows between the two nations. However, current existing studies are constrained by a reduced spatial scale (e.g., a single community or municipality) or a short time-window (e.g. <10 years), which limits our long-term nationwide understanding of the climate-migration relationship. To tackle this, we employed high-resolution (municipal-level) and long-term databases (1970–2009), which included nation-level interviews, border patrol apprehensions, and high-resolution precipitation. Our results showed that the decadal and maximum migratory fluxes in these four decades corresponded to years with low precipitation. In particular, the migration of low-income rural farmers tripled during drought, representing as much as a third of all historical migration. It is very likely that rural people were pushed to leave their lands as the result of strongly diminished rainfed agriculture and pastureland production, their main livelihood. Our results suggest that policy oriented to reduce the negative impacts of drought (such as livestock drought insurances and the provisioning of drought-resistant seeds), particularly to marginal farmers in arid ecosystems, could be an effective way to reduce current and future migratory peaks between Mexico and the USA.
Journal Article
Role of MicroRNA-7 (MiR-7) in Cancer Physiopathology
2022
miRNAs are non-coding RNA sequences of approximately 22 nucleotides that interact with genes by inhibiting their translation through binding to their 3′ or 5′ UTR regions. Following their discovery, the role they play in the development of various pathologies, particularly cancer, has been studied. In this context, miR-7 is described as an important factor in the development of cancer because of its role as a tumor suppressor, regulating a large number of genes involved in the development and progression of cancer. Recent data support the function of miR-7 as a prognostic biomarker in cancer, and miR-7 has been proposed as a strategy in cancer therapy. In this work, the role of miR-7 in various types of cancer is reviewed, illustrating its regulation, direct targets, and effects, as well as its possible relationship to the clinical outcome of cancer patients.
Journal Article
Roles and Regulation of BCL-xL in Hematological Malignancies
by
Morales-Martínez, Mario
,
Vega, Mario I.
in
Apoptosis
,
Apoptosis - genetics
,
bcl-X Protein - genetics
2022
Members of the Bcl-2 family are proteins that play an essential role in the regulation of apoptosis, a crucial process in development and normal physiology in multicellular organisms. The essential mechanism of this family of proteins is given by the role of pro-survival proteins, which inhibit apoptosis by their direct binding with their counterpart, the effector proteins of apoptosis. This family of proteins was named after the typical member Bcl-2, which was named for its discovery and abnormal expression in B-cell lymphomas. Subsequently, the structure of one of its members BCL-xL was described, which allowed one to understand much of the molecular mechanism of this family. Due to its role of BCL-xL in the regulation of cell survival and proliferation, it has been of great interest in its study. Due to this, it is important to research its role regarding the development and progression of human malignancies, especially in hematologic malignancies. Due to its variation in expression in cancer, it has been suggested that BCL-xL can or cannot play a role in cancer depending on the cellular or tissue context. This review discusses recent advances in its transcriptional regulation of BCL-xL, as well as the advances regarding the activities of BCL-xL in hematological malignancies, its possible role as a biomarker, and its possible clinical relevance in these malignancies.
Journal Article
Knowing Our Enemy in the Antimicrobial Resistance Era: Dissecting the Molecular Basis of Bacterial Defense Systems
2024
Bacteria and their phage adversaries are engaged in an ongoing arms race, resulting in the development of a broad antiphage arsenal and corresponding viral countermeasures. In recent years, the identification and utilization of CRISPR–Cas systems have driven a renewed interest in discovering and characterizing antiphage mechanisms, revealing a richer diversity than initially anticipated. Currently, these defense systems can be categorized based on the bacteria’s strategy associated with the infection cycle stage. Thus, bacterial defense systems can degrade the invading genetic material, trigger an abortive infection, or inhibit genome replication. Understanding the molecular mechanisms of processes related to bacterial immunity has significant implications for phage-based therapies and the development of new biotechnological tools. This review aims to comprehensively cover these processes, with a focus on the most recent discoveries.
Journal Article
Structural Basis of Resistant Starch (RS) in Bread: Natural and Commercial Alternatives
2019
Bread is categorized as having a high amount of rapidly digested starch that may result in a rapid increase in postprandial blood glucose and, therefore, poor health outcomes. This is mostly the result of the complete gelatinization that starch undergoes during baking. The inclusion of resistant starch (RS) ingredients in bread formulas is gaining prominence, especially with the current positive health outcomes attributed to RS and the apparition of novel RS ingredients in the market. However, many RS ingredients contain RS structures that do not resist baking and, therefore, are not suitable to result in a meaningful RS increase in the final product. In this review, the structural factors for the resistance to digestion and hydrothermal processing of RS ingredients are reviewed, and the definition of each RS subtype is expanded to account for novel non-digestible structures recently reported. Moreover, the current in vitro digestion methods used to measure RS content are critically discussed with a view of highlighting the importance of having a harmonized method to determine the optimum RS type and inclusion levels for bread-making.
Journal Article
Abundance, diversity and domain architecture variability in prokaryotic DNA-binding transcription factors
by
Hernandez-Guerrero, Rafael
,
Sanchez, Israel
,
Armenta-Medina, Dagoberto
in
Abundance
,
Archaeal Proteins - genetics
,
Archaeal Proteins - metabolism
2018
Gene regulation at the transcriptional level is a central process in all organisms, and DNA-binding transcription factors, known as TFs, play a fundamental role. This class of proteins usually binds at specific DNA sequences, activating or repressing gene expression. In general, TFs are composed of two domains: the DNA-binding domain (DBD) and an extra domain, which in this work we have named \"companion domain\" (CD). This latter could be involved in one or more functions such as ligand binding, protein-protein interactions or even with enzymatic activity. In contrast to DBDs, which have been widely characterized both experimentally and bioinformatically, information on the abundance, distribution, variability and possible role of the CDs is scarce. Here, we investigated these issues associated with the domain architectures of TFs in prokaryotic genomes. To this end, 19 families of TFs in 761 non-redundant bacterial and archaeal genomes were evaluated. In this regard we found four main groups based on the abundance and distribution in the analyzed genomes: i) LysR and TetR/AcrR; ii) AraC/XylS, SinR, and others; iii) Lrp, Fis, ArsR, and others; and iv) a group that included only two families, ArgR and BirA. Based on a classification of the organisms according to the life-styles, a major abundance of regulatory families in free-living organisms, in contrast with pathogenic, extremophilic or intracellular organisms, was identified. Finally, the protein architecture diversity associated to the 19 families considering a weight score for domain promiscuity evidenced which regulatory families were characterized by either a large diversity of CDs, here named as \"promiscuous\" families given the elevated number of variable domains found in those TFs, or a low diversity of CDs. Altogether this information helped us to understand the diversity and distribution of the 19 Prokaryotes TF families. Moreover, initial steps were taken to comprehend the variability of the extra domain in those TFs, which eventually might assist in evolutionary and functional studies.
Journal Article
S3505 A Case of Invasive Gastrointestinal Mold Infection
by
Risinger, James
,
Zhong, Boris
,
Amundsen, Tyson
in
Cytomegalovirus
,
Gastroenterology
,
Infections
2022
Journal Article
BUNCH: A Hierarchical Filtering Algorithm for Identifying Persistent Entities in Interactive Particle Systems
2025
Detecting trajectories of hierarchical structures in a dynamical system of multiple interacting particles is an open problem that is typically addressed by imposing strong constraints on the structures to be found. Here, we describe BUNCH, a dynamical filtering algorithm that can efficiently and on-the-fly fit dynamical trajectories of multiple particles to a tree structure of Gaussian clusters that can model a wide range of hierarchically arranged structures, while extracting and calculating hierarchical properties such as complexity, lifespan, and other information- and time-based properties of an entity (an object defined by its structure) and of all of its constituting subentities. Unlike other (hierarchical) clustering algorithms, BUNCH emphasizes independence from adjustable parameters and ascribes equal importance to each hierarchy level and its attending attributes, of the tree of clusters that best fits an evolving particle system. We illustrate the performance of BUNCH via an operational definition of “lifeness” of an entity, as the product of its defining information (algorithmic complexity) integrated over its lifetime, in units of information × time. Thus we provide a proof of concept that measuring and quantifying level-wise properties of hierarchically modeled systems with BUNCH is feasible for small enough particle systems, thereby enabling the classification of entities and subentities via the measurement of hierarchical properties.
Journal Article
Comparative genomics of DNA-binding transcription factors in archaeal and bacterial organisms
by
Martinez-Liu, Luis
,
Martinez-Nuñez, Mario Alberto
,
Peeters, Eveline
in
Amino acids
,
Archaea
,
Archaeabacteria
2021
Archaea represent a diverse phylogenetic group that includes free-living, extremophile, mesophile, symbiont, and opportunistic organisms. These prokaryotic organisms share a high significant similarity with the basal transcriptional machinery of Eukarya, and they share regulatory mechanisms with Bacteria, such as operonic organization and DNA-binding transcription factors (TFs). In this work, we identified the repertoire of TFs in 415 archaeal genomes and compared them with their counterparts in bacterial genomes. The comparisons of TFs, at a global level and per family, allowed us to identify similarities and differences between the repertoires of regulatory proteins of bacteria and archaea. For example, 11 of 62 families are more highly abundant in archaea than bacteria, and 13 families are abundant in bacteria but not in archaea and 38 families have similar abundances in the two groups. In addition, we found that archaeal TFs have a lower isoelectric point than bacterial proteins, i.e., they contain more acidic amino acids, and are smaller than bacterial TFs. Our findings suggest a divergence occurred for the regulatory proteins, even though they are common to archaea and bacteria. We consider that this analysis contributes to the comprehension of the structure and functionality of regulatory proteins of archaeal organisms.
Journal Article