Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551014
Pertenecen a esta colección Tesis y Trabajos de grado de los Doctorados correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
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- Discovery and comprehensive evaluation of new strategies for the postharvest biocontrol of anthracnose in avocado(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-06-10) Gallardo Camarena, Marco Vinicio; Licona Cassani, Cuauhtémoc; emimmayorquin; Reverchon, Frédérique; Méndez Bravo, Alfonso; Villalobos Escobedo, José Manuel; School of Engineering and Sciences; Campus Monterrey; Torres Acosta, Mario AntonioAnthracnose, caused mainly by Colletotrichum spp, is the leading postharvest disease affecting avocado (Persea americana), contributing to significant losses in global production. As concerns grow over the environmental impact and diminishing efficacy of synthetic fungicides, this study aimed to identify and evaluate microbial antagonists as sustainable biocontrol alternatives. Microorganisms were isolated from two primary sources: extreme environments in Cuatro Ciénegas, known for their oligotrophic and selective conditions; and various niches of the avocado ecosystem, including rhizosphere, carposphere, bark, and nectar. A total of 30 actinobacteria, 78 filamentous fungi, and other 13 bacterial isolates were screened in vitro against Colletotrichum spp., with promising candidates further evaluated through in vivo inhibition assays. Among the strains tested, Kosakonia cowanii VG1, isolated from the avocado carposphere, exhibited strong antifungal activity across assays. Genome analysis revealed biosynthetic gene clusters encoding siderophores and azole-containing RiPPs, which may underlie its inhibitory effects. The techno-economic evaluation showed a competitive production cost of $0.11 per dose, highlighting its scalability potential. Actinobacterial isolate Streptomyces nanshensis CC402A also demonstrated an effective in vitro and in vivo inhibition, with a low MIC and MFC of the crude extract. This isolate presents gene clusters for known antifungal metabolites, including valinomycin and HSAF-like compounds. This work supports the integration of prospecting in environments with strong ecological selective pressures, genomic mining, and economic modeling to discover and validate new microbial biocontrol agents.
- Exploring the chemical diversity of environmental actinobacteria using genome mining and synthetic biology(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-06) González Salazar, Luz Angela; Licona Cassani, Cuauhtémoc; emipsanchez; Pacheco Moscoa, Adriana; De la Torre Zavala, Susana; Rodríguez López, Carlos; School of Engineering and Sciences; Campus Monterrey; Cruz Morales, PabloNatural products derived from biosynthetic gene clusters (BGCs) in microorganisms are vital for medicine, agriculture, and industry. However, rediscovering known compounds and the resource-intensive nature of drug development delays the discovery of novel compounds. This study aimed to address these challenges by integrating genome mining and synthetic biology to explore the chemical diversity of actinobacteria from the oligotrophic environment of Cuatro Ciénegas, Mexico. In the first chapter of this work, we evaluate the genomic and biosynthetic potential of the environmental strains Lentzea sp. CC55 and Actinokineospora sp. PR83 isolated from Cuatro Ciénegas environment. Comparative genomics revealed open pan-genomes comprising 568 and 965 unique genes, respectively. BGC similarity networks identified unique clusters, including terpenes, RiPPs, NRPS, and polyketides. Both strains demonstrated antimicrobial and cytotoxic activities. Lentzea sp. CC55 culture showed cytotoxic activity only in liquid cultures while Actinokineospora sp. PR83 presented activity against B. subtilis for solid media. The Biosynthetic Novelty Index (BiNI) confirmed these strains as high-priority candidates for novel natural product discovery. In the second chapter, we applied the BiNI index in our collection of strains from Cuatro Ciénegas to select the candidates with the highest novelty. From the selected candidates we standardized cloning strategies for BGC expression in heterologous hosts. Using Golden Gate assembly and CRISPR/Cas9-based DNA assembly, genes were domesticated, assembled into transcriptional units, and transferred to Streptomyces albidoflavus UO-FLAV-004. Challenges with toxic fragments and incomplete assemblies were resolved using optimized host strains, resulting in the successful conjugation of core modules and the initiation of heterologous expression. In the third chapter, we explore different tools of metabolomics for the detection of metabolites produced by engineered strains. For NRPS the prediction indicates a theoretical mass: 495 Da. The RiPP corresponds to a lanthipeptide type I with a theoretical mass of 2318.9 Da. Molecular network analysis and dereplication only identified compounds produced intrinsically encoded by the host. This research presents a genomic-guide pipeline for exploring the biosynthetic potential of Cuatro Ciénegas actinobacteria, providing insights into the BGC prioritization and application of synthetic biology techniques to improve the intricate pipelines for new chemical diversity in Natural Products research.
- Design and characterization of a biosensor for the detection of codon-readthrough inducers(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-02-28) Trejo Alarcón, Luisa María; Licona Cassani, Cuauhtémoc; emipsanchez; Utrilla Carreri, José; García Echauri, Sergio A.; Rodríguez López, Carlos Eduardo; García García, Jorge Donato; Escuela de Ingeniería y Ciencias; Campus Monterrey; Cruz Morales, PabloLas enfermedades raras afectan a menos del 0.05% de la población mundial y se atribuyen en gran medida a desórdenes genéticos que generan proteínas incompletas. Los inductores de codon-readthrough (CR), como algunos aminoglucósidos (AGs), han sido evaluados como terapias potenciales debido a su capacidad para restaurar la traducción de genes afectados. En este trabajo, desarrollamos un biosensor eficiente basado en levaduras para la detección de moléculas con actividad CR. Construimos una cepa de Saccharomyces cerevisiae con un plásmido conteniendo el gen reportero de luminiscencia nluc modificado para incluir un codón de terminación prematura (PTC), lo que lo hace no funcional. La actividad CR, inducida por AGs comerciales como G418, gentamicina, tobramicina y paromomicina, restauran la funcionalidad del gen, generando una señal de luminiscencia en ensayos in vivo en microplaca. El sistema fue aplicado al análisis de 91 cepas de actinobacterias aisladas, identificando un potencial inductor de CR, proveniente de la cepa Streptomyces sp. CR101A. A través de minería genómica, fraccionamiento por Cromatografía Líquida de Ultra Alta Resolución (UPLC) y espectrometría de masas (MS), se identificó un clúster de genes biosintéticos (BGC) como responsable de la producción de una molécula con un anillo ciclitol. Actualmente, se trabaja con herramientas de biología sintética como CRISPR/Cas9 para la generación de mutantes y expresión heteróloga, para confirmar la implicación del BGC detectado en la producción del inductor de CR.