Publications by authors named "Melissa Vázquez-Carrada"

2 Publications

  • Page 1 of 1

Chitosan resistance by the deletion of the putative high affinity glucose transporter in the yeast Ustilago maydis.

Carbohydr Res 2021 Jul 5;505:108335. Epub 2021 May 5.

Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Departamento de Microbiología, Prolongación de Carpio y Plan de Ayala S/N, Col. Sto. Tomas, Del. Miguel Hidalgo, CP 11340, Ciudad de México, Mexico. Electronic address:

Chitosan is a polycationic amino-sugar polymer soluble in acidic pH. As a potential antifungal, it has been tested against several fungi. Its main mode of action is the permeabilization of cell membrane by the interaction with specific membrane sites. Ustilago maydis, an attractive fungal model used in biochemical and biotechnology research, is highly sensitive to chitosan, with extensive membrane destruction that results in cell death. Using the Golden Gate system, several mutant strains with deletions in monosaccharide transporters were obtained and tested against chitosan in order to know the implications of these membrane proteins in the sensitivity of the fungus against chitosan. Δum11514/03895 strain, a mutant with a deletion in a hypothetical high affinity glucose transporter, showed resistance to chitosan. Morphological characterization of the mutant displayed an apparent increase in mitochondrial content, but oxygen consumption as well as growth rate were not affected by the gene deletion. Alteration in cell wall surface was observed in the mutant strain. In contrast to wild type, the Δum11514/03895 strain showed integrity of cell wall and cell membrane in the presence of chitosan. The resistance against chitosan is likely associated to the modification of cell wall architecture and is not related to energy-depend process.
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http://dx.doi.org/10.1016/j.carres.2021.108335DOI Listing
July 2021

Autophagosomes accumulation in the vacuoles of the fungus Ustilago maydis and the role of proteases in their digestion.

FEMS Microbiol Lett 2019 05;366(10)

Departamento de Ingeniería Genética del Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional Unidad Irapuato. 36821, Irapuato Guanajuato, México.

In the present study we determined whether Ustilago maydis accumulates autophagosomes within vacuoles when the cells are exposed to nutritional stress conditions. We investigated whether proteinase B and proteinase A are involved in their degradation. To this effect, wild type and Δpep4 mutant were incubated in minimal medium lacking a carbon source. It was observed that after incubation in nutrient-deficient media, spherical bodies appeared within the Δpep4 mutant strains vacuoles. In addition, autophagosomes were accumulated in U. maydis WT cells incubated in the presence of the serine protease inhibitor PMSF and accumulation of large autophagosomes and electrodense structures in the Δpep4 mutant cell vacuoles took place. These results demonstrate that the homologues of both, the proteinase B and the protease A, are involved in the autophagosomes degradation process in U. maydis.
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http://dx.doi.org/10.1093/femsle/fnz108DOI Listing
May 2019