Person: López Montero, Iván
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First Name
Iván
Last Name
López Montero
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Química Física
Area
Química Física
Identifiers
12 results
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Item Expansion microscopy applied to mono- and dual-species biofilms(Biofilms and Microbiomes, 2023) Valdivieso González, David; Jara Pérez, Josué; Almendro Vedia, Víctor Galileo; Orgaz Martín, Belén; López Montero, IvánExpansion microscopy (ExM) is a new super-resolution technique based on embedding the biological sample within a hydrogel and its physical expansion after swelling. This allows increasing its size by several times while preserving its structural details. Applied to prokaryotic cells, ExM requires digestion steps for efficient expansion as bacteria are surrounded by a rigid cell wall. Furthermore, bacteria can live in social groups forming biofilms, where cells are protected from environmental stresses by a self-produced matrix. The extracellular matrix represents an additional impenetrable barrier for ExM. Here we optimize the current protocols of ExM and apply them to mono- and dual-species biofilms formed by clinical isolates of Limosilactobacillus reuteri, Enterococcus faecalis, Serratia marcescens and Staphylococcus aureus. Using scanning electron microscopy for comparison, our results demonstrate that embedded bacteria expanded 3-fold. Moreover, ExM allowed visualizing the three-dimensional architecture of the biofilm and identifying the distribution of different microbial species and their interactions. We also detected the presence of the extracellular matrix after expansion with a specific stain of the polysaccharide component. The potential applications of ExM in biofilms will improve our understanding of these complex communities and have far-reaching implications for industrial and clinical research.Item Rheology of Pseudomonas fluorescens biofilms: From experiments to predictive DPD mesoscopic modeling(Journal of chemical physics, 2023) Martín Roca, José; Bianco, Valentino; Alarcón, Francisco; Monnappa, Ajay K.; Natale, Paolo; Monroy, Francisco; Orgaz Martín, Belén; López Montero, Iván; Valeriani, ChantalBacterial biofilms mechanically behave as viscoelastic media consisting of micron-sized bacteria cross-linked to a self-produced network of extracellular polymeric substances (EPSs) embedded in water. Structural principles for numerical modeling aim at describing mesoscopic viscoelasticity without losing details on the underlying interactions existing in wide regimes of deformation under hydrodynamic stress. Here, we approach the computational challenge to model bacterial biofilms for predictive mechanics in silico under variable stress conditions. Up-to-date models are not entirely satisfactory due to the plethora of parameters required to make them functioning under the effects of stress. As guided by the structural depiction gained in a previous work with Pseudomonas fluorescens [Jara et al., Front. Microbiol. 11, 588884 (2021)], we propose a mechanical modeling by means of Dissipative Particle Dynamics (DPD), which captures the essentials of topological and compositional interactions between bacterial particles and cross-linked EPS-embedding under imposed shear. The P. fluorescens biofilms have been modeled under mechanical stress mimicking shear stresses as undergone in vitro. The predictive capacity for mechanical features in DPD-simulated biofilms has been investigated by varying the externally imposed field of shear strain at variable amplitude and frequency. The parametric map of essential biofilm ingredients has been explored by making the rheological responses to emerge among conservative mesoscopic interactions and frictional dissipation in the underlying microscale. The proposed coarse grained DPD simulation qualitatively catches the rheology of the P. fluorescens biofilm over several decades of dynamic scaling. Published under an exclusive license by AIP Publishing.- Project number: 224
Item Entorno multimedia y OpenSource para la enseñanza de la Física con material interactivo() Almendro Vedia, Víctor Galileo; Fortún García, Adelia; López Montero, Iván; Valdivieso González, David Item The GDP-Bound State of Mitochondrial Mfn1 Induces Membrane Adhesion of Apposing Lipid Vesicles through a Cooperative Binding Mechanism(Biomolecules, 2020) Tolosa Díaz, Andrés; Almendro Vedia, Víctor Galileo; Natale, Paolo; López Montero, IvánMitochondria are double-membrane organelles that continuously undergo fission and fusion. Outer mitochondrial membrane fusion is mediated by the membrane proteins mitofusin 1 (Mfn1) and mitofusin 2 (Mfn2), carrying a GTP hydrolyzing domain (GTPase) and two coiled-coil repeats. The detailed mechanism on how the GTP hydrolysis allows Mfns to approach adjacent membranes into proximity and promote their fusion is currently under debate. Using model membranes built up as giant unilamellar vesicles (GUVs), we show here that Mfn1 promotes membrane adhesion of apposing lipid vesicles. The adhesion forces were sustained by the GDP-bound state of Mfn1 after GTP hydrolysis. In contrast, the incubation with the GDP:AlF− 4 , which mimics the GTP transition state, did not induce membrane adhesion. Due to the flexible nature of lipid membranes, the adhesion strength depended on the surface concentration of Mfn1 through a cooperative binding mechanism. We discuss a possible scenario for the outer mitochondrial membrane fusion based on the modulated action of Mfn1.Item ATP Synthesis and Biosensing Coupled to the Electroenzymatic Activity of a Hydrogenase on an Electrode/Biomimetic Membrane Interface(Proceedings, 2017) Pita, Marcos; Gutierrez-Sanchez, Cristina; Natale, Paolo; García-Molina, Gabriel; Marquez, Ileana F.; Marques, Marta C.; Zacarias, Sonia; Pereira, Ines A. C.; López Montero, Iván; Velez, Marisela; Lacey, Antonio L. DeItem Intracellular pH-Induced Tip-to-Tip Assembly of Gold Nanorods for Enhanced Plasmonic Photothermal Therapy(ACS Omega, 2016) Ahijado Guzmán, Rubén; Bañares Morcillo, Luis; Guerrero Martínez, Andrés; López Montero, Iván; Tardajos Rodríguez, Gloria María; González Rubio, Guillermo; Izquierdo, Jesús G.; Calzado Martín, Alicia; Calleja, MontserratThe search for efficient plasmonic photothermal therapies using nonharmful pulse laser irradiation at the near-infrared (NIR) is fundamental for biomedical cancer research. Therefore, the development of novel assembled plasmonic gold nanostructures with the aim of reducing the applied laser power density to a minimum through hot-spot-mediated cell photothermolysis is an ongoing challenge. We demonstrate that gold nanorods (Au NRs) functionalized at their tips with a pH-sensitive ligand assemble into oligomers within cell lysosomes through hydrogen-bonding attractive interactions. The unique intracellular features of the plasmonic oligomers allow us to significantly reduce the femtosecond laser power density and Au NR dose while still achieving excellent cell killing rates. The formation of gold tip-to-tip oligomers with longitudinal localized surface plasmon resonance bands at the NIR, obtained from low-aspect-ratio Au NRs close in resonance with 800 nm Ti:sapphire 90 fs laser pulses, was found to be the key parameter for realizing the enhanced plasmonic photothermal therapy.Item Mitochondrial Na+ controls oxidative phosphorylation and hypoxic redox signalling(Nature (London), 2020) Hernansanz Agustín, Pablo; Choya Foces, Carmen; Carregal Romero, Susana; Ramos, Elena; Oliva, Tamara; Villa Piña, Tamara; Moreno, Laura; Izquierdo Alvarez, Alicia; Cabrera Garcia, J.Daniel; Cortés, Ana; Lechuga Vieco, Ana Victoria; Jadiya, Pooja; Navarro, Elisa; Parada, Esther; Palomino Antolín, Alejandra; Tello, Daniel; Acín Pérez, Rebeca; Rodríguez Aguilera, Juan Carlos; Navas, Plácido; Cogolludo, Angel; López Montero, Iván; Martínez del Pozo, Álvaro; Egea, Javier; López, Manuela G.; Elrod, John W.; Ruiz Cabello, J.; Bogdanova, Anna; Enríquez, José Antonio; Martínez Ruiz, AntonioAll metazoans depend on O2 delivery and consumption by the mitochondrial oxidative phosphorylation (OXPHOS) system to produce energy. A decrease in O2 availability (hypoxia) leads to profound metabolic rewiring. In addition, OXPHOS uses O2 to produce reactive oxygen species (ROS) that can drive cell adaptations through redox signalling, but also trigger cell damage1–4, and both phenomena occur in hypoxia4–8. However, the precise mechanism by which acute hypoxia triggers mitochondrial ROS production is still unknown. Ca2+ is one of the best known examples of an ion acting as a second messenger9, yet the role ascribed to Na+ is to serve as a mere mediator of membrane potential and collaborating in ion transport10. Here we show that Na+ acts as a second messenger regulating OXPHOS function and ROS production by modulating fluidity of the inner mitochondrial membrane (IMM). We found that a conformational shift in mitochondrial complex I during acute hypoxia11 drives the acidification of the matrix and solubilization of calcium phosphate precipitates. The concomitant increase in matrix free-Ca2+ activates the mitochondrial Na+/Ca2+ exchanger (NCLX), which imports Na+ into the matrix. Na+ interacts with phospholipids reducing IMM fluidity and mobility of free ubiquinone between complex II and complex III, but not inside supercomplexes. As a consequence, superoxide is produced at complex III, generating a redox signal. Inhibition of mitochondrial Na+ import through NCLX is sufficient to block this pathway, preventing adaptation to hypoxia. These results reveal that Na+ import into the mitochondrial matrix controls OXPHOS function and redox signalling through an unexpected interaction with phospholipids, with profound consequences in cellular metabolism.Item Tunable gold nanorod/NAO conjugates for selective drug delivery in mitochondria-targeted cancer therapy(Nanoscale, 2022) González-Rubio, Sergio; Salgado, Cástor; Manzaneda González, Vanesa; Muñoz Úbeda, Mónica; Ahijado Guzmán, Rubén; Natale, Paolo; Almendro Vedia, Víctor Galileo; Junquera González, María Elena; Osío Barcina, José De Jesús; Ferrer, Irene; Guerrero Martínez, Andrés; Paz-Ares Rodríguez, Luis Gonzaga; López Montero, IvánItem Polar ammoniostyryls easily converting a clickable Q1 lipophilic BODIPY in an advanced plasma membrane probe†(Journal of Materials Chemistry B, 2023) Serrano-Buitrago, Sergio; Muñoz Úbeda, Mónica; Almendro Vedia, Víctor Galileo; Sánchez-Camacho, Juan; Lora Maroto, Beatriz; Moreno, Florencio; Bañuelos, Jorge; García-Moreno, Inmaculada; López Montero, Iván; Moya Cerero, Santiago De La; Moreno Jiménez, FlorencioA very simple, small and symmetric, but highly bright, photostable and functionalizable molecular probe for plasma membrane (PM) has been developed from an accessible, lipophilic and clickable organic dye based on BODIPY. To this aim, two lateral polar ammoniostyryl groups were easily linked to increase the amphiphilicity of the probe and thus its lipid membrane partitioning. Compared to the BODIPY precursor, the transversal diffusion across lipid bilayers of the ammoniostyryled BODIPY probe was highly reduced, as evidenced by fluorescence confocal microscopy on model membranes built up as giant unilamellar vesicles (GUVs). Moreover, the ammoniostyryl groups endow the new BODIPY probe with the ability to optically work (excitation and emission) in the bioimaging-useful red region, as shown by staining of the plasma membrane of living mouse embryonic fibroblasts (MEFs). Upon incubation, this fluorescent probe rapidly entered the cell through the endosomal pathway. By blocking the endocytic trafficking at 4 °C, the probe was confined within the PM of MEFs. Our experiments show the developed ammoniostyrylated BODIPY as a suitable PM fluorescent probe, and confirm the synthetic approach for advancing PM probes, imaging and science.Item Transgene expression in mice of the Opa1 mitochondrial transmembrane protein through bicontinuous cubic lipoplexes containing gemini imidazolium surfactants(Journal of Nanobiotechnology, 2021) Muñoz Úbeda, Mónica; Semenzato, Martina; Franco-Romero, Anais; Junquera González, María Elena; Aicart Sospedra, Emilio; Scorrano, Luca; López Montero, IvánLipoplexes are non-viral vectors based on cationic lipids used to deliver DNA into cells, also known as lipofection. The positively charge of the hydrophilic head-group provides the cationic lipids the ability to condensate the negatively charged DNA into structured complexes. The polar head can carry a large variety of chemical groups including amines as well as guanidino or imidazole groups. In particular, gemini cationic lipids consist of two positive polar heads linked by a spacer with different length. As for the hydrophobic aliphatic chains, they can be unsaturated or saturated and are connected to the polar head-groups. Many other chemical components can be included in the formulation of lipoplexes to improve their transfection efficiency, which often relies on their structural features. Varying these components can drastically change the arrangement of DNA molecules within the lamellar, hexagonal or cubic phases that are provided by the lipid matrix. Lipofection is widely used to deliver genetic material in cell culture experiments but the simpler formulations exhibit major drawbacks related to low transfection, low specificity, low circulation half-life and toxicity when scaled up to in vivo experiments.