Person: Gutiérrez Fernández, Juan Carlos
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First Name
Juan Carlos
Last Name
Gutiérrez Fernández
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Genética, Fisiología y Microbiología
Area
Microbiología
Identifiers
6 results
Search Results
Now showing 1 - 6 of 6
Item Metallic Nanoparticles—friends or foes in the battle against antibiotic-Resistant Bacteria?(Microorganisms, 2021) Amaro Torres, Francisco; Morón García, Álvaro; Díaz del Toro, Silvia; Martín González, Ana María; Gutiérrez Fernández, Juan CarlosThe rapid spread of antibiotic resistances among bacteria demands novel strategies for infection control, and metallic nanoparticles appear as promising tools because of their unique size and tunable properties that allow their antibacterial effects to be maximized. Furthermore, their diverse mechanisms of action towards multiple cell components have suggested that bacteria could not easily develop resistance against nanoparticles. However, research published over the last decade has proven that bacteria can indeed evolve stable resistance mechanisms upon continuous exposure to metallic nanoparticles. In this review, we summarize the currently known individual and collective strategies employed by bacteria to cope with metallic nanoparticles. Importantly, we also discuss the adverse side effects that bacterial exposure to nanoparticles may have on antibiotic resistance dissemination and that might constitute a challenge for the implementation of nanoparticles as antibacterial agents. Overall, studies discussed in this review point out that careful management of these very promising antimicrobials is necessary to preserve their efficacy for infection control.Item High resistance of Tetrahymena thermophila to paraquat: Mitochondrial alterations, oxidative stress and antioxidant genes expression(Chemosphere, 2016) Díaz del Toro, Silvia; Martín González, Ana María; Cubas, Liliana; Ortega, Ruth; Amaro, Francisco; Rodríguez-Martín, Daniel; Gutiérrez Fernández, Juan CarlosItem Autophagy and lipid droplets are a defense mechanism against toxic copper oxide nanotubes in the eukaryotic microbial model Tetrahymena thermophila(Science of the Total Environment, 2022) Morón García, Álvaro; Martín González, Ana María; Díaz del Toro, Silvia; Gutiérrez Fernández, Juan Carlos; Amaro Torres, FranciscoThe widespread use of inorganic nanomaterials of anthropogenic origin has significantly increased in the last decade, being now considered as emerging pollutants. This makes it necessary to carry out studies to further understand their toxicity and interactions with cells. In the present work we analyzed the toxicity of CuO nanotubes (CuONT) in the ciliate Tetrahymena thermophila, a eukaryotic unicellular model with animal biology. CuONT exposure rapidly induced ROS generation in the cell leading to oxidative stress and upregulation of genes encoding antioxidant enzymes (catalase, superoxide dismutase, glutathione peroxidase), metal-chelating metallothioneins and cytochrome P450 monooxygenases. Comet assays and overexpression of genes involved in DNA repair confirmed oxidative DNA damage in CuONT-treated cells. Remarkably, both electron and fluorescent microscopy revealed numerous lipid droplets and autophagosomes containing CuONT aggregates and damaged mitochondria, indicating activation of macroautophagy, which was further confirmed by a dramatic upregulation of ATG (AuTophaGy related) genes. Treatment with autophagy inhibitors significantly increased CuONT toxicity, evidencing the protective role of autophagy towards CuONTinduced damage. Moreover, increased formation of lipid droplets appears as an additional mechanism of CuONT detoxification. Based on these results, we present a hypothetical scenario summarizing how T. thermophila responds to CuONT toxicity. This study corroborates the use of this ciliate as an excellent eukaryotic microbial model for analyzing the cellular response to stress caused by toxic metal nanoparticles.Item The Tetrahymena metallothionein gene family: twenty-one new cDNAs, molecular characterization, phylogenetic study and comparative analysis of the gene expression under different abiotic stressors(BMC Genomics, 2016) Francisco Martínez, Patricia de; Melgar, Laura María; Díaz del Toro, Silvia; Martín González, Ana María; Gutiérrez Fernández, Juan CarlosBackground: Ciliate metallothioneins (MTs) are included in family 7 of the MT superfamily. This family has been divided into two main subfamilies: 7a or CdMTs and 7b or CuMTs. All ciliate MTs reported have been isolated from different Tetrahymena species and present unique features with regard to standard MTs. Likewise, an expression analysis has been carried out on some of MT genes under metal stress, corroborating their classification into two subfamilies. Results: We isolated 21 new cDNAs from different Tetrahymena species to obtain a wider view of the biodiversity of these conserved genes. Structural analysis (cysteine patterns) and an updated phylogenetic study both corroborated the previous classification into two subfamilies. A new CuMT from a Tetrahymena-related species Ichthyophthirius multifiliis was also included in this general analysis. We detected a certain tendency towards the presentation of a CdMT tri-modular structure in Borealis group species with respect to Australis group. We report for the first time a semi-complete paralog duplication of a CdMT gene originating a new CdMT gene isoform in T. malaccensis. An asymmetry of the codon usage for glutamine residues was detected between Cd- and CuMTs, and the phylogenetic implications are discussed. A comparative gene expression analysis of several MT genes by qRTPCR revealed differential behavior among them under different abiotic stressors in the same Tetrahymena species. Conclusions: The Tetrahymena metallothionein family represents a quite conserved proteinstructure group with unique features with respect to standard MTs. Both Cd- and CuMT subfamilies present very defined and differentiated characteristics at several levels: cysteine patterns, modular structure, glutamine codon usage and gene expression under metal stress, among others. Gene duplication through evolution seems to be the major genetic mechanism for creating new MT gene isoforms and increasing their functional diversity.- Project number: 115
Item Microbiologí@ en tu pantalla: laboratorios virtuales para la enseñanza práctica de Microbiología Ambiental en los Grados de Biología y Bioquímica con un enfoque semipresencial (blended learning)(2021) Amaro Torres, Francisco; Díaz del Toro, Silvia; Martín-González, Ana María; Gutiérrez Fernández, Juan Carlos; Rovira Sanroque, José Vicente; García Avilés, Javier; Palá Paul, Jesús; Sobrino Gómez, Esther; González Belinchón, Carmen Martina; Herráiz Moreno, Marta; Fernández de Cuevas López, Fernando; de Francisco Martínez, PatriciaEl proyecto de innovación tiene como principal objetivo implementar la metodología de enseñanza-aprendizaje blended learning en las clases prácticas de la asignatura “Biología de la contaminación” (Grado en Biología UCM, cuarto curso) creando una colección de laboratorios virtuales en sinergia con las sesiones de docencia práctica presencial. De esta forma la colección de recursos digitales que reune este proyecto complementará la formación que reciben los alumnos en las clases prácticas de laboratorio de la asignatura, y permitirá adaptar las prácticas a un formato de educación online o semipresencial en el contexto de situaciones similares a la actual crisis sanitaria derivada de la COVID-19. Item Environmental Biosensors: A Microbiological View(Handbook of Cell Biosensors, 2020) Gutiérrez Fernández, Juan Carlos; Amaro Torres, Francisco; Díaz del Toro, Silvia; Martín González, Ana María; Thouand, G.In this mini-review, the potential of using microorganisms to design biosensors for detecting environmental pollutants is analyzed and discussed. A distinction is made between a classical biosensor (CB) and a whole-cell biosensor (WCB), emphasizing their structural components and the possibility of using whole microorganisms as their bioreceptor elements. The advantages and disadvantages of using prokaryotic microorganisms as opposed to eukaryotic microorganisms are described. Likewise, the advantages of using protozoa ciliates) over other eukaryotic microorganisms are also shown. We analyze the current bibliography on biosensors built on microorganisms as bioreceptors of pollutant molecules, such as inorganic (metal (loid)s) or organic (xenobiotics). New trends, such as the prokaryotic riboswitches, microbial two-component systems where the pollutant can be simultaneously detected and bioremediated, along with advances in synthetic biology, are shown as promising tools in the design of environmental biosensors.