Person:
Martín González, Ana María

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First Name
Ana María
Last Name
Martín González
URI
https://hdl.handle.net/20.500.14352/74438
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Biológicas
Department
Genética, Fisiología y Microbiología
Area
Microbiología
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2018 - 20193
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Author: Francisco Martínez, Patricia de × Subject: 575 ×

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Now showing 1 - 3 of 3
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    Structural and Functional Diversity of Microbial Metallothionein Genes
    (Microbial Diversity in the Genomic Era, 2018) Gutiérrez Fernández, Juan Carlos; Francisco Martínez, Patricia de; Amaro Torres, Francisco; Díaz, Silvia; Martín González, Ana María; Das, Surajit; Dash, Hirak Ranjan
    In the present review, we discussed the concept of metallothionein (MT) and analyzed the structural and functional diversity of microbial MTs, grouping them into three main groups; bacteria, fungi, and protists. Structural diversity is analyzed based on the primary, secondary, and/or tertiary structure of the proteins. Their ability to bind different metals is also analyzed in each microbial group. An in silico and phylogenetic analysis of MT sequences from the main microbial groups has been carried out. The wide functional diversity of these proteins and the regulation of the MT gene expression are also discussed. The presence of several paralog genes in many microorganisms provides a coordinated and multiple response against different types of environmental stressors. Likewise, the main possible biotechnological applications of these proteins are explored, such as molecular tools to design biosensors for evaluating metal contamination and in metal bioremediation.
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    Selenium cytotoxicity in Tetrahymena thermophila: New clues about its biological effects and cellular resistance mechanisms
    (Science of the Total Environment, 2019) Romero Sobrino, Iván; Francisco Martínez, Patricia de; Gutiérrez, Juan Carlos; Martín González, Ana María
    Selenium is an essential micronutrient but at high concentrations can produce severe cytotoxicity and genomic damage. We have evaluated the cytotoxicity, ultrastructural and mitochondrial alterations of the two main selenium inorganic species; selenite and selenate, in the eukaryotic microorganism Tetrahymena thermophila. In this ciliate, selenite is more toxic than selenate. Their LC50 values were calculated as 27.65 μM for Se(IV) and 56.88 mM for Se(VI). Significant levels of peroxides/hydroperoxides are induced under low-moderate selenite or selenate concentrations. Se(VI) exposures induce an immediate mitochondrial membrane depolarization. Selenium treated cells show an intense vacuolization and some of them present numerous discrete and small electrondense particles, probably selenium deposits. Mitochondrial fusion, an intense swelling in peripheral mitochondria and mitophagy are detected in selenium treated cells, especially in those exposed to Se (IV). qRT-PCR analysis of diverse genes, encoding relevant antioxidant enzymes or other proteins, like metallothioneins, involved in an environmental general stress response, have shown that they may be crucial against Se(IV) and/or Se (VI) cytotoxicity.
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    AP-1 (bZIP) Transcription Factors as Potential Regulators of Metallothionein Gene Expression in Tetrahymena thermophila
    (Frontiers in Genetics, 2018) Francisco Martínez, Patricia de; Amaro Torres, Francisco; Martín González, Ana María; Gutiérrez Fernández, Juan Carlos
    Metallothioneins (MT) are multi-stress proteins mainly involved in metal detoxification. MT gene expression is normally induced by a broad variety of stimulus and its gene expression regulation mainly occurs at a transcriptional level. Conserved motifs in the Tetrahymena thermophila MT promoters have been described. These motifs show a consensus sequence very similar to AP-1 sites, and bZIP type transcription factors might participate in the MT gene expression regulation. In this research work, we characterize four AP-1 transcription factors in each of four different analyzed Tetrahymena species, detecting a high conservation among them. Each AP-1 molecule has its counterpart in the other three Tetrahymena species. A comparative qRT-PCR analysis of these AP-1 genes have been carried out in different T. thermophila strains (including metal-adapted, knockout and/or knockdown strains among others), and under different metal-stress conditions (1 or 24 h Cd2+, Cu2+, or Pb2+ treatments). The possible interaction of these transcription factors with the conserved AP-1 motifs present in MT promoters has been corroborated by protein-DNA interaction experiments. Certain connection between the expression patterns of the bZIP and MT genes seems to exist. For the first time, and based on our findings, a possible gene expression regulation model including both AP-1 transcription factors and MT genes from the ciliate T. thermophila has been elaborated.