Biology subjects

Martinez, V.

Publications and source records attributed to Martinez, V..

15 recordsLinked to original sources

bioRxiv2026

Methyl-substituted 1,10-phenanthroline derivatives in copper(II) complexes enhance antitumor activity and inhibit NHE1 in MDA-MB-231 breast cancer cells

Three copper(II) complexes containing 1,10-phenanthroline derivatives, [CuCl2(phen)].0.5H2O (1), [CuCl2(neo)].0.75H2O (2), and [CuCl2(tmp)].H2O (3), were evaluated for their antitumor activity in MDA-MB-231 breast cancer cells. All complexes markedly reduced cell viability, exhibiting significantly lower IC values and higher selectivity indices than the corresponding free ligands, CuCl2, and cisplatin, highlighting the therapeutic advantage of metal complexation. Among them, only 1 induced DNA damage at sub-IC concentrations. Cytotoxicity in all complexes was associated with intracellular ROS generation and apoptosis, although 2 and 3 produced a stronger oxidative response. Complex 3 additionally promoted necrosis. Cell proliferation was inhibited in a concentration-dependent manner, accompanied by increased intracellular copper accumulation. Moreover, 2 and 3 significantly inhibited Na/H exchanger 1 (NHE1) activity, reducing cell migration and MMP-9 activity. Western blot analysis further demonstrated that all three complexes modulated the expression of NHE1, G protein-coupled estrogen receptor (GPER), and apoptosis-related proteins. Overall, our findings show that ligand methylation enhances the antitumor activity of copper(II) complexes and shifts their mechanism of action from DNA damage-driven cytotoxicity toward ROS-mediated apoptosis, while also improving inhibition of NHE1-dependent migratory pathways. These results identify NHE1 as a key molecular target underlying the enhanced antitumor activity of methylated phenanthroline copper(II) complexes.

cell biology↗

bioRxiv2026

The Anaphase Promoting Complex targets the toxic protein Progerin for ubiquitin-dependent degradation via autophagy

The premature aging disease Hutchinson-Gilford Progeria Syndrome (HGPS) results from the accumulation of progerin, a cytotoxic protein generated from a point mutation in the Lamin A/C gene, in the nuclear lamina. Upon the proper stimulation, cells degrade progerin, reversing cellular HGPS phenotypes; however, there is still a gap in our knowledge concerning which pathways are mediating progerin degradation. Previous data has demonstrated that the Anaphase Promoting Complex (APC), a multi-subunit ubiquitin ligase, tagets proteins for degradation, and that a decrease in APC function is linked with cellular aging. To determine if the APC is linked to HGPS disease phenotypes, we performed a meta-analysis of RNA-seq data from skin samples isolated from HGPS patients and identified dysregulation of several genes encoding subunits and substrates of the APC. Stimulation of APC activity decreased progerin protein levels and significantly decreased the number of cells with nuclear blebs. Proximity ligation assays (PLA) demonstrated that APC structure is compromised in HGPS cells and that APC stimulation increases proximity of the APC with progerin. Coimmunoprecipitation revealed that the APC co-activator, CDC20, physically interacted with nuclear lamina proteins. We further demonstrate that APC-mediated progerin degradation occurs through autophagy. Inhibition of the 26S proteasome enhanced progerin degradation, providing additional support for APC mediated-progerin degradation occurring independent of the proteasome. As such, we propose a previously unidentified interaction and mechanism by which cells remove progerin. This finding has impact on potential therapeutic strategies for HGPS, as well as providing further insight into linking the APC with both normal and premature aging.

cell biology↗

bioRxiv2026

SlCIPK26 enhances tomato fertility by activating the K+ transporter SlHAK5 in reproductive tissues

In tomato plants, the potassium (K) transporter SlHAK5 is integral to root K uptake and overall plant fertility. Under K deficiency, SlHAK5 expression is induced in roots and the encoded transporter is activated via the Ca{superscript 2}-sensing CIPK/CBL complex SlCIPK23/SlCBL1-9. In Arabidopsis, multiple CIPK/CBL complexes can activate AtHAK5, providing alternative regulatory pathways that enhance K uptake. However, the architecture of CIPK/CBL signaling networks has diverged among plant species, necessitating species-specific identification of novel regulatory components. Accordingly, we screened additional tomato CIPK proteins for their capacity to modulate SlHAK5 activity in yeast. SlCIPK15 and SlCIPK26 emerged as potent activators of SlHAK5, acting in concert with SlCBL9. Functional characterization of slcipk15 and slcipk26 mutants revealed that neither contributed significantly to SlHAK5-mediated K uptake in roots. Conversely, both mutants exhibited impaired pollen tube elongation, correlating with reduced K content in pollen relative to wild type. Notably, slcipk26 mutants displayed more severe pollen defects, phenocopying the slhak5 mutant. Further analyses demonstrated that slcipk26 plants suffered compromised seed set and pistil function, paralleling the reproductive deficiencies observed in slhak5 mutants. These findings implicate SlCIPK26 as the principal regulator of SlHAK5 in reproductive tissues. Collectively, our data underscore the role of CIPK paralogs in orchestrating tissue-specific regulation of target proteins, thereby enabling fine-tuned modulation of K transport essential for both vegetative and reproductive development.

plant biology↗

bioRxiv2026

Metabolic feedback during bacterial fermentation is a motility brake

We study an unexpectedly fast decay of motility in dense suspensions of Escherichia coli bacteria supplied with excess glucose under anaerobic conditions. The decrease in swimming speed occurs on a timescale inversely proportional to the cell concentration, and is associated with the secretion of organic acids by the bacteria. We show that the decay is driven by the progressive accumulation of non-ionised organic acids in the medium, and develop a chemical kinetic model that successfully predicts the swimming speed variations over a range of conditions in the presence of these acids. We further measure the internal pH of E. coli cells exposed to organic acids, and find that the speed decay coincides with sharp declines in internal pH and metabolic rate. Our findings identify an additional layer of motility control that can arise in complex environments even when motility genes are expressed and energy sources are abundant. This mechanism is likely relevant for understanding bacterial motility in habitats such as the human gut, where high densities of bacteria and organic acids are common.

microbiology↗

bioRxiv2026

Alamandine/MrgD Pathway Modulates Gut-Bone Marrow Axis in Aging

Aging is associated with colon epithelial barrier integrity and upregulation of myelopoiesis in the bone marrow (BM). Alamandine (Ala) and MrgD are novel members of the renin angiotensin system (RAS). This study tested the hypothesis that Ala restores the colon epithelial barrier integrity in aging via modulating gut-BM axis. Mice of age 2-3 (Young) or 22-24 months (Old) were treated with saline or Ala by using Osmotic pumps. The intestinal permeability was evaluated by using FITC-dextran. Lgr5+Olfm4+ intestinal stem cells (ISCs), Wnt3a and {beta}-catenin were evaluated by immunohistochemistry or western blotting. Fecal microbiome was analyzed by 16S rRNA sequencing. Monocyte-macrophages were characterized by flow cytometry. Cecal or serum bacterial metabolites were analyzed. The pro-myelopoietic potential of cecal supernatants (CS) was tested in the Young-BM cells. MrgD was expressed in ISCs, which was decreased in the Old. Increased intestinal permeability in aging was reversed by Ala. In the colon organoids, Ala increased Wnt3a levels that were antagonized by the NF449, SQ22536 or 666-15. Ala restored phospho-CREB and active {beta}-catenin levels that were decreased in the Old colon-organoids. Ala increased the richness and {beta}-diversity of the aging microbiome and decreased Bacillota/Bacteroidota. Ala decreased the CD80+ and increased CX3CR+ cells in the Old colons. Old-CS induced myelopoiesis in vitro in BM cells with higher number of monocytes and pro-inflammatory macrophages which was not observed in the CS derived from Ala-treated Old mice. Ala is a promising pharmacological agent for reversing the leaky gut of aging by restoring homeostasis in the gut-BM axis.

pharmacology and toxicology↗

bioRxiv2025

A major QTL for resistance against Salmonid Rickettsial Septicaemia in coho salmon (Oncorhynchus kisutch) maps to a narrow region on chromosome 21, implicating two candidate genes

The facultative intracellular bacterium Piscirickettsia salmonis causes Salmon Rickettsial Syndrome (SRS) in Coho salmon, Atlantic salmon, and other salmonids. SRS causes large mortalities in Chilean aquaculture and leads to heavy usage of antibiotics. In Atlantic salmon SRS resistance is a polygenic trait with moderate to large heritability. In coho salmon a large QTL for SRS-resistance was earlier found on chromosome 21. In the present study we have further characterized genetic resistance to SRS in coho salmon and searched for putative candidate genes underlying the QTL. The mean heritability of survival was 0.31 and 0.58 on the observed and liability scale, respectively. The QTL on chromosome 21 explained from 26% to 97% of genetic variation within 12 different datasets. Two SNPs were substantially more significant compared to other SNPs and in very strong linkage disequilibrium with each other. The resistance allele was found to be dominant over the susceptibility allele at these SNPs. One of the two SNPs was located within the first exon of two genes which are transcribed in opposite directions: a histidine triad nucleotide-binding protein 3 (hint3) gene and a gene (LOC109866666) encoding a long non-coding RNA (lncRNA). Genotypes at the SNP were correlated with expression levels at both hint3 and the lncRNA gene, and the differential expression was manifested in both SRS-challenged and non-challenged fish. The exonic SNP is located 3 base pairs upstream of the start codon of the hint3 gene, at a position which is crucial for effective translation according to the rules of Kozak. The resistance allele at the SNP correlates to increased expression levels and increased translation levels at hint3, although the latter remains to be experimentally proven. Thus, it seems plausible that the QTL is due to the action of the hint3 gene and/or the gene lncRNA gene encoded by LOC109866666. The hint3 gene on chromosome 21 is different from homologs in Atlantic salmon, and no Atlantic salmon homologs of LOC109866666 were found. Thus, it might be possible to increase SRS-resistance of Atlantic salmon by inserting the coho gene(s) through gene editing.

genomics↗

bioRxiv2025

Schwann cells modified to secrete MANF is a potential cellular therapy for peripheral nerve regeneration

Despite several decades of research, an effective therapy for peripheral nerve regeneration is still lacking. The lack of knowledge of molecular candidates that equally promote axon regeneration and glial cell dynamics essential for regeneration poses challenges in developing effective therapies. Improper optimization of potential therapies leading to failures in ensuring their local availability in nerves also poses additional challenges. Here, we showed that the neurotrophic factor, the mesencephalic astrocyte-derived neurotrophic factor (MANF), equally promotes axon regeneration and glial cell dynamics favorable for nerve regeneration. We showed that while endogenous expression of MANF is primarily restricted to non-peptidergic sensory neurons in adult rats, exogenous MANF promotes the growth of all subtypes of adult rat sensory neurons. We also demonstrated that exogenous MANF promotes the proliferation and migration of adult rat primary Schwann Cells (SCs). Further, we found that local and repeated administration of exogenous MANF to injured mouse nerve promote axon regeneration. Finally, we devised a therapeutic approach by programming nerve resident SCs to locally and continuously deliver MANF to injured rat nerves and showed that this approach improved nerve regeneration indices. Overall, this work developed a therapeutic approach by harnessing the power of SCs as a local delivery system of MANF for improving nerve regeneration.

neuroscience↗

bioRxiv2024

Role of the NHE1 exchanger in the antitumor effects of copper(II) complexes and phenanthroline derivatives

Three copper(II) complexes containing 1,10-phenanthroline ([CuCl2(phen)]{middle dot}4H2O,1), neocuproine ([CuCl2(neo)]{middle dot}4H2O, 2) and tetramethyl-phenanthroline ([CuCl2(tmp)]{middle dot}4H2O, 3) as the primary ligand and another three copper(II) complexes with the L-Ala-Phe dipeptide as an auxiliary ligand: [Cu(L-Ala-Phe)(phen)]{middle dot}4H2O (4), [Cu(L-Ala-Phe)(neo)]{middle dot}4H2O (5) and [Cu(L-Ala-Phe)(tmp)]{middle dot}4H2O (6), inhibited cell viability in breast cancer MCF-7 cell line, both in the monolayer and spheroid cell culture models. The pair with tetramethyl-phenanthroline displayed a better selectivity index than cisPt and non-cytotoxicity-related ROS induction and apoptosis in the monolayer breast cancer model. Cell proliferation was affected by all compounds in a concentration-dependent manner, with a more substantial effect on the tetramethyl-phenanthroline complexes. Cell viability on multicellular spheroids showed a concentration-dependent reduction from 1 M, with IC50 that were half the one for cisplatin. All copper complexes, except for 1 showed DNA damage, demonstrated by the comet assay at a concentration below the IC50. The role of NHE1 has been linked to many types of cancers. Our study revealed that all compounds inhibited NHE1 activity in MCF-7 cells. However, only complexes containing the dipeptide auxiliary ligand could extend their effect on cell migration (Wound Healing Assay) and MMP-9 activity studied by zimography. Wester Blot analysis showed that expressions of MMP-2, MMP-9, and NHE1 were affected when MCF7 cells were treated with the six compounds as well. Overall, our results reveal an antitumor effect of all copper(II) complexes studied in breast cancer cells and a fundamental role of NHE1 in cell migration.

cancer biology↗

bioRxiv2024

Graphical Representation of Landscape Heterogeneity Identification through Unsupervised Acoustic Analysis

O_LIChanges in land use and climate change threaten global biodiversity and ecosystems, calling for the urgent development of effective conservation strategies. Recognizing landscape heterogeneity, which refers to the variation in natural features within an area, is crucial for these strategies. While remote sensing images quantify landscape heterogeneity, they might fail to detect ecological patterns in moderately disturbed areas, particularly at minor spatial scales. This is partly because satellite imagery may not effectively capture undergrowth conditions due to its resolution constraints. In contrast, soundscape analysis, which studies environmental acoustic signals, emerges as a novel tool for understanding ecological patterns, providing reliable information on habitat conditions and landscape heterogeneity in complex environments across diverse scales and serving as a complement to remote sensing methods. C_LIO_LIWe propose an unsupervised approach using passive acoustic monitoring data and network inference methods to analyze acoustic heterogeneity patterns based on biophony composition. This method uses sonotypes, unique acoustic entities characterized by their specific time-frequency spaces, to establish the acoustic structure of a site through sonotype occurrences, focusing on general biophony rather than specific species and providing information on the acoustic footprint of a site. From a sonotype composition matrix, we use the Graphical Lasso method, a sparse Gaussian graphical model, to identify acoustic similarities across sites, map ecological complexity relationships through the nodes (sites) and edges (similarities), and transform acoustic data into a graphical representation of ecological interactions and landscape acoustic diversity. C_LIO_LIWe implemented the proposed method across 17 sites within an oil palm plantation in Santander, Colombia. The resulting inferred graphs visualize the acoustic similarities among sites, reflecting the biophony achieved by characterizing the landscape through its acoustic structures. Correlating our findings with ecological metrics like the Bray-Curtis dissimilarity index and satellite imagery indices reveals significant insights into landscape heterogeneity. C_LIO_LIThis unsupervised approach offers a new perspective on understanding ecological and biological interactions and advances soundscape analysis. The soundscape decomposition into sonotypes underscores the methods advantage, offering the possibility to associate sonotypes with species and identify their contribution to the similarity proposed by the graph. C_LI

ecology↗

bioRxiv2024

Circulating mucosal-like IgA responses associate with severity of Puumala orthohantavirus-caused hemorrhagic fever with renal syndrome

Old World Orthohantaviruses cause hemorhagic fever with renal syndrome (HFRS) characterized by increased vascular permeability and acute kidney injury (AKI). Despite the systemic nature of the disease, the virus enters humans through inhalation and therefore initially encounters the immunoglobulin class A (IgA) dominated mucosal immune system. Herein, we characterized systemic IgA responses and their potential relationship to the mucosal immune activation by examining blood samples obtained from patients hospitalized due to acute Puumala orthohantavirus infection. Our findings reveal increased frequencies of IgA-expressing circulating mucosal-associated B1 cells and plasmablasts, as well as elevated levels of polyreactive, polymeric, virus-specific and secretory IgA in the acute stage of the disease. Importantly, the levels of circulating virus-specific and secretory IgA associated with the severity of AKI. Furthermore, circulating polymeric IgA displayed enhanced effector functions by forming stable complexes with the IgA receptor CD89 and induced pro-inflammatory neutrophil responses. These results suggest that, while an efficient mucosal immune response is likely to be crucial for infection clearance, an excessive mucosal immune activation may contribute to HFRS disease progression.

immunology↗

bioRxiv2024

Orthohantavirus Diversity in Central-East Argentina: Insights from Complete Genomic Sequencing on Phylogenetics, Geographic patterns and Transmission scenarios.

Hantavirus Pulmonary Syndrome (HPS), characterized by its high fatality rate, poses a significant public health concern in the Americas. Phylogenetic relationships of orthohantaviruses in the country were inferred from partial genomic sequences. The objectives of this work were to report new complete viral genomes of the known viral variants associated with HPS cases in Central-East region of Argentina, to assess viral diversity, phylogenetic relationships, and to elucidate the geographic patterns of distribution of each variant. To accomplish this, a detailed analysis was conducted of the geographic distribution of reported cases within the most impacted province of the region. The phylogenetic analysis defined clearly separated clades in the country according to their geographic origin. Andes virus (ANDV) segregated from the rest of the sequences, and those representative from the Central East region, Buenos Aires (BAV) and Lechiguanas virus (LECV), were grouped in the same cluster but segregated in two different branches. ImportanceIn Argentina, most of the HPS cases were associated with ANDV and closely related viruses distributed in four endemic regions. This work focused on obtaining and studying the complete genome of the orthohantaviruses present in the Central East (CE) region (BAV and LECV). Both viruses were responsible for major and minor outbreaks of person- to-person transmission in the country, and the findings may pave the way to study the impact of genetic determinants of viral transmission and to consider the reclassification of the species Orthohantavirus andesense.

genomics↗

bioRxiv2023

Andes virus genome mutations that are likely associated with animal-model attenuation and human person-to-person transmission

STRUCTURED ABSTRACTO_ST_ABSAbstractC_ST_ABSWe performed whole-genome sequencing with bait-enrichment techniques to analyze Andes virus (ANDV), a cause of human hantavirus pulmonary syndrome. We used cryopreserved lung tissues from a naturally infected long-tailed colilargo; early, intermediate, and late cell-culture passages of an ANDV isolate from that animal; and lung tissues from golden hamsters experimentally exposed to that ANDV isolate. The resulting complete genome sequences were subjected to detailed comparative genomic analysis against American orthohantaviruses. We identified four amino-acid substitutions related to cell-culture adaptation that resulted in attenuation of ANDV in the typically lethal golden hamster animal model of hantavirus pulmonary syndrome. Mutations in the ANDV nucleocapsid protein, glycoprotein, and small nonstructural protein open reading frames correlated with mutations typical for ANDV strains associated with increased pathogenesis in the small animal model. Finally, we identified three amino-acid substitutions, two in the small nonstructural protein and one in the glycoprotein, that were only present in the clade of viruses associated with person-to-person efficient transmission. Our results indicate that there are virulence-associated and transmission-associated single-nucleotide polymorphisms that could be used to predict strain-specific ANDV virulence and/or transmissibility. ImportanceSeveral orthohantaviruses cause the zoonotic disease hantavirus pulmonary syndrome (HPS) in the Americas. Among them, HPS caused by Andes virus (ANDV) is of great public-health concern because it is associated with the highest case-fatality rate (up to 50%). ANDV is also the only orthohantavirus associated with relatively robust evidence of person-to-person transmission. This work reveals nucleotide changes in the ANDV genome that are associated with virulence attenuation in an animal model and increased transmissibility in humans. These findings may pave the way to early severity predictions in future ANDV-caused HPS outbreaks.

microbiology↗

bioRxiv2022

Distinct types of multicellular aggregates in Pseudomonas aeruginosa liquid cultures

Pseudomonas aeruginosa forms suspended multicellular aggregates when cultured in liquid media. Such aggregates may be important in disease, and/or as a pathway to biofilm formation. The polysaccharide Psl and extracellular DNA (eDNA) have both been implicated in aggregation, but previous results depend strongly on the experimental conditions. Here we develop a quantitative microscopy-based method for assessing changes in the size distribution of suspended aggregates over time in growing cultures. For exponentially growing cultures of P. aeruginosa PAO1, we find that aggregation is mediated by cell-associated Psl, rather than by either eDNA or se-creted Psl. These aggregates arise de novo within the culture via a growth process that involves both collisions and clonal growth. They are "non-cheatable" since Psl non-producing cells do not aggregate with producers. In contrast, we find that stationary phase (overnight) cultures contain a different type of multicelullar aggregate, in which both eDNA and Psl mediate cohesion. Our findings suggest that the physical and bi-ological properties of multicellular aggregates may be very different in early-stage vs late-stage bacterial cultures.

microbiology↗

bioRxiv2020

Synchronization and interaction of proline, ascorbate and oxidative stress pathways under abiotic stress combination in tomato plants

ABSTRACTAdverse environmental conditions have a devastating impact on plant productivity. In nature, multiple abiotic stresses occur simultaneously, and plants have evolved unique responses to cope against this combination of stresses. Here, we coupled genome-wide transcriptional profiling and untargeted metabolomics with physiological and biochemical analyses to characterize the effect of salinity and heat applied in combination on the metabolism of tomato plants. Our results demonstrate that this combination of stresses causes a unique reprogramming of metabolic pathways, including changes in the expression of 1,388 genes and the accumulation of 568 molecular features. Pathway enrichment analysis of transcript and metabolite data indicated that the proline and ascorbate pathways act synchronously to maintain cellular redox homeostasis, which was supported by measurements of enzymatic activity and oxidative stress markers. We also identified key transcription factors from the basic Leucine Zipper Domain (bZIP), Zinc Finger Cysteine-2/Histidine-2 (C2H2) and Trihelix families that are likely regulators of the identified up-regulated genes under salinity+heat combination. Our results expand the current understanding of how plants acclimate to environmental stresses in combination and unveils the synergy between key cellular metabolic pathways for effective ROS detoxification. Our study opens the door to elucidating the different signaling mechanisms for stress tolerance.HIGHLIGHTSThe combination of salinity and heat causes a unique reprogramming of tomato metabolic pathways by changing the expression of specific genes and metabolic features.Proline and ascorbate pathways act synchronously to maintain cellular redox homeostasisKey transcription factors from the basic Leucine Zipper Domain (bZIP), Zinc Finger Cysteine-2/Histidine-2 (C2H2) and Trihelix families were identified as putative regulators of the identified up-regulated genes under salinity and heat combination.View Full Text

plant biology↗

bioRxiv2018

Antlions are sensitive to subnanometer amplitude vibrations carried by sand substrates

European pit-building antlions (Myrmeleon inconspicuus / Rambur 1842) are studied in their capacity to detect vibrations generated by the locomotion of an ant (Cataglyphis cursor) outside the pit. These locomotions have been recorded by laser velocimetry and copied in detail in their time sequences. The sequences are replicated by micro-controllers digital outputs acting on piezoelectric transducers placed several centimeters outside the peripheries of the pits: their actions on the surface of a sand media create surface waves with particle accelerations that are 3 orders of magnitude less than g, alleviating any possibility of sand avalanche towards the bottom of the pit. Depending on the amplitude of the vibrations, the antlions answer back, generally by sand tossing. One remarkable feature is the time delay from the start of the cue and the aggressive behavior induced by this cue. This time delay is studied versus the cue amplitude. The result of this work is that anlions answer back within minutes to cues with amplitudes between 1 to 2 nanometers at the level of their mechanosensors, and within seconds to these same cues if they are preceded by a sequence of signals at the [A]ngstrom amplitude. This induced aggressive behaviour evidences the sensitivity to vibrations at extremely low level.

physiology↗