Luis Felipe Jiménez-García

Staphylococcus spp., other than S. aureus (SOSA, formerly CoNS), are opportunistic pathogens often linked to biofilm infections on indwelling devices. Their rising antibiotic resistance highlights the need for novel therapies. Bacteriophages are promising due to their specificity and ability to inhibit cell growth and biofilm formation. In this study, lytic phages isolated from swab pools were characterized against six clinical S. epidermidis and S. warneri isolates. Two distinct groups were identified via their host range, transmission electron microscopy, and genome sequencing. Group 1 phage ΘBRJ9 belongs to genus Sepunavirus (Myoviridae), while Group 2 phage ΘBRJ18 belongs to genus Andhravirus (Podoviridae). Both showed rapid adsorption, short latent periods (20 min), and high burst sizes (79 and 60 PFU/cell). They strongly inhibited planktonic SOSA growth at MOI 10, with efficacy comparable to or better than vancomycin, and their genomes lacked lysogeny, virulence, or resistance genes. These phages display a lytic lifestyle and are candidates for targeted SOSA therapies. Future work will assess biofilm efficacy, antibiotic synergies, and in vivo performance.

Chagas disease, caused by Trypanosoma cruzi, remains a neglected tropical disease of relevance due to its chronic complications and limited therapeutic options. Current treatments, mainly benznidazole and nifurtimox, are limited by toxicity, adverse effects, and reduced efficacy in chronic infection. Therefore, antimicrobial peptides (AMPs) have emerged as promising candidates for identifying new antiparasitic strategies because of their ability to affect multiple cellular targets. In this study, we evaluated the anti-trypanosomal activity, host-cell cytotoxicity, and cellular alterations induced by the human salivary peptide Histatin 5 (Hist 5) against T. cruzi epimastigotes. The reversibility of the antiparasitic effect was assessed through washout assays after 48 h of exposure. Cytotoxicity was evaluated in Vero cells and RAW264.7 macrophages, whereas parasite susceptibility was determined using dose–response curves. The reversibility of the antiparasitic effect was assessed through washout assays after 48 h of exposure. Ultrastructural alterations induced by Hist 5 were analyzed by transmission electron microscopy. Cell death-associated events were assessed using Annexin V/PI staining and TUNEL assays to detect phosphatidylserine externalization and DNA fragmentation, respectively. Reactive oxygen species and nitric oxide production were quantified using 2′,7′-dichlorodihydrofluorescein diacetate (H₂DCFDA) fluorescence and the Griess reaction. Hist 5 showed limited cytotoxicity toward mammalian cells and reduced parasite viability in a time- and concentration-dependent manner. Following peptide removal, parasite growth recovered only partially, indicating that the antiparasitic effect was not completely reversible. Hist 5 also induced marked ultrastructural damage, apoptosis-like cell death, increased intracellular ROS levels, and enhanced NO production. These findings suggest that Hist 5 affects T. cruzi epimastigotes through multiple cellular alterations while exerting limited effects on host-cell viability.

Dengue is the most prevalent arthropod-borne viral disease, caused by infection with the dengue virus (DENV). Severe dengue is characterized by significant vasculopathy involving a proinflammatory and procoagulant state associated with increased vascular permeability. However, the host–virus interactions driving this process remain incompletely elucidated. Monocytes (Mø) are primary target cells during DENV infection and actively release extracellular vesicles, like microparticles (MPs), mediating intercellular communication, contributing to dengue pathogenesis. Here, we evaluated whether MPs released by DENV-infected monocytes represent a previously underappreciated mechanism contributing to dengue-associated vascular dysfunction. The vascular endothelium plays a determining role in the response to injury because it functions as a regulatory interface during hemostasis (coagulation–fibrinolysis–inflammation) and by preserving the endothelial barrier. We found that these vesicles transport viral proteins (E and NS1), exhibit a procoagulant profile that promotes thrombin generation, and enhance endothelial vascular cell (EVC) activation. DENV-infected THP-1 Mø MPs interaction induces a shift toward a procoagulant, proinflammatory, and proadherent phenotype, characterized by increased expression of PAR-1, TF, ICAM-1, and VCAM-1, reflecting the establishment of a sustained HMEC-1 EVC activation that compromises vascular barrier integrity. This leads to increased permeability, a hallmark of DENV-associated vasculopathy and a central event in the progression to severe dengue.

Dengue is the most prevalent arthropod-borne viral disease, caused by infection with dengue virus (DENV). Severe dengue is characterized by significant vasculopathy involving a proinflammatory and procoagulant state associated with increased vascular permeability. However, the host–virus interactions driving this process remain incompletely elucidate. Monocytes are primary target cells during DENV infection and actively release extracellular vesicles, like microparticles (MPs), mediating intercellular communication contributing to dengue pathogenesis. Here, we evaluated whether MPs released by DENV-infected monocytes represent a previously underappreciated mechanism contributing to dengue-associated vascular dysfunction. The vascular endothelium plays a determining role in the response to injury because it functions as a regulatory interface during hemostasis (coagulation–fibrinolysis–inflammation) and by preserving endothelial barrier. We found that these vesicles transport viral components capable of mediating DENV endothelial vascular cells (EVC) infection, while simultaneously exhibiting a procoagulant profile promoting thrombin generation and cell activation. DENV-infected Mø MPs interaction induces a shift toward a procoagulant, proinflammatory, and proadherent phenotype, characterized by increased expression of PAR-1, TF, ICAM-1, and VCAM-1, reflecting the establishment of a sustained EVC activation that compromises vascular barrier integrity, leading to increased permeability, a hallmark of DENV-associated vasculopathy and a central event in the progression to severe dengue.

Introduction: Suicide is a significant public health problem, with increased rates in low- and middle-income countries such as Mexico; therefore, suicide prevention is important. Suicide is a complex and multifactorial phenomenon in which biological and social factors are involved. Several studies on the biological mechanisms of suicide have analyzed the proteome of the dorsolateral prefrontal cortex (DLPFC) in people who have died by suicide. The aim of this work was to analyze the protein expression profile in the DLPFC of individuals who died by suicide in comparison to age-matched controls in order to gain information on the molecular basis in the brain of these individuals and the selection of potential biomarkers for the identification of individuals at risk of suicide. In addition, this information was analyzed using machine learning (ML) algorithms to propose a model for predicting suicide.Methods: Brain tissue (Brodmann area 9) was sampled from male cases (n=9) and age-matched controls (n=7). We analyzed the proteomic differences between the groups using two-dimensional polyacrylamide gel electrophoresis and mass spectrometry. Bioinformatics tools were used to clarify the biological relevance of the differentially expressed proteins. In addition, this information was analyzed using machine learning (ML) algorithms to propose a model for predicting suicide.Results: Twelve differentially expressed proteins were also identified (t₁₄ ≤ 0.5). Using Western blotting, we validated the decrease in expression of peroxiredoxin 2 and alpha-internexin in the suicide cases. ML models were trained using densitometry data from the 2D gel images of each selected protein and the models could differentiate between both groups (control and suicide cases).Discussion: Our exploratory pathway analysis highlighted oxidative stress responses and neurodevelopmental pathways as key processes perturbed in the DLPFC of suicides. Regarding ML models, KNeighborsClassifier was the best predicting conditions. Here we show that these proteins of the DLPFC may help to identify brain processes associated with suicide and they could be validated as potential biomarkers of this outcome.

Hemileia vastatrix coffee leaf rust reduces Mexican coffee production by 51%. We aimed to analyze the size and distribution of H. vastatrix urediniospores among coffee plantations, as well as the morphological structures of the uredinium. In 2015, 65 leaf samples with rust symptoms were collected from 17 coffee cultivars grown at various altitudes (229–1649 m) under different environmental conditions in 14 regions of four Mexican states. A total of 30 spores per sample were measured and grouped using the Ward centroid method, and the group distribution was analyzed. Uredinia morphology was examined via electron microscopy, and the identity of the rust was confirmed. We identified eight significant spore groups. Groups 8h and 3a had the smallest and largest spores, respectively, which were distributed in two and one state, respectively, at different altitudes. The spores in groups 1b–7f were variable within the intermediate size range, and their distribution was at least one group per state under temperate, warm, and humid conditions. The uredinium had double-cell walls in the pedicels and urediniospores, a split septum, spores with hilum and protuberances, and an oval spore shape; anastomosis was detected on vegetative hyphae and haustoria. These findings may reflect gaps in knowledge in the biological cycle of this rust.

Baculovirus is one of the most complex viruses found in nature. Proteomic analysis of budded viruses (BVs) indicates that they are formed by at least 50 different structural proteins. The function of most of these structural proteins and their specific localization in individual virions remain unknown. In the present study, we have conducted single-molecule localization microscopy analysis of the spatial distribution of the nucleocapsid protein P24 and the envelope proteins GP64 and E25. Our results show that P24 and GP64 are polarized to one end of the baculovirus, while E25 distributes more homogenously along the viral envelope. This is the first study using optical microscopy to demonstrate the polarized distribution of structural proteins in individual baculoviruses.

Chagas Disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi, affecting 6–8 million people, mainly in Latin America. The medical treatment is based on two compounds, benznidazole and nifurtimox, with limited effectiveness and that produce severe side effects; consequently, there is an urgent need to develop new, safe, and effective drugs. Amphotericin B is the most potent antimycotic known to date. A21 is a derivative of this compound with the property of binding to ergosterol present in cell membranes of some organisms. In the search for a new therapeutic drug against T. cruzi, the objective of this work was to study the in vitro and in vivo effects of A21 derivative on T. cruzi. Our results show that the A21 increased the reactive oxygen species and reduced the mitochondrial membrane potential, affecting the morphology, metabolism, and cell membrane permeability of T. cruzi in vitro. Even more important was finding that in an in vivo murine model of infection, A21 in combination with benznidazole was able to reduce blood parasitemia, diminish the immune inflammatory infiltrate in skeletal muscle and rescue all the mice from death due to a virulent T. cruzi strain.

Nuclear speckles are compartments enriched in splicing factors present in the nucleoplasm of eucaryote cells. Speckles have been studied in mammalian culture and tissue cells, as well as in some non-mammalian vertebrate cells and invertebrate oocytes. In mammals, their morphology is linked to the transcriptional and splicing activities of the cell through a recruitment mechanism. In rats, speckle morphology depends on the hormonal cycle. In the present work, we explore whether a similar situation is also present in non-mammalian cells during the reproductive cycle. We studied the speckled pattern in several tissues of a viviparous reptile, the lizard Sceloporus torquatus, during two different stages of reproduction. We used immunofluorescence staining against splicing factors in hepatocytes and oviduct epithelium cells and fluorescence and confocal microscopy, as well as ultrastructural immunolocalization and EDTA contrast in Transmission Electron Microscopy. The distribution of splicing factors in the nucleoplasm of oviductal cells and hepatocytes coincides with the nuclear-speckled pattern described in mammals. Ultrastructurally, those cell types display Interchromatin Granule Clusters and Perichromatin Fibers. In addition, the morphology of speckles varies in oviduct cells at the two stages of the reproductive cycle analyzed, paralleling the phenomenon observed in the rat. The results show that the morphology of speckles in reptile cells depends upon the reproductive stage as it occurs in mammals.