Ciencias Exactas y Ciencias de la Salud
Permanent URI for this collectionhttps://hdl.handle.net/11285/551039
Pertenecen a esta colección Tesis y Trabajos de grado de las Maestrías correspondientes a las Escuelas de Ingeniería y Ciencias así como a Medicina y Ciencias de la Salud.
Browse
Search Results
- Evaluation of the contribution of maize germ peroxidases to resistance to the storage pest prostephanus truncatus(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2025-07) Cervantes Macedo, Elizabeth; García Lara, Silverio; emipsanchez; School of Engineering and Sciences; Campus Monterrey; González Rodríguez, América TzitzikiMaize is a globally important crop used for food, feed, and bioethanol production. However, during storage, it faces serious threats from biotic factors, such as insect pests, particularly Prostephanus truncatus, which can cause severe grain damage and losses of up to 80%, depending on the region and conditions. These infestations also affect grain quality, nutritional value, and marketability. Maize kernels exhibit various resistance mechanisms involving structural, genetic, and biochemical traits, including proteins like peroxidases. Recent studies have linked peroxidase activity to insect resistance, with activity detected in kernel tissues, including the aleurone layer, pedicel, and germ. Although peroxidase activity is mainly concentrated in the germ, little is known about the specific peroxidases involved and their role during insect interactions, creating a gap in our understanding of this defense mechanism. This research aims to analyze the role of germ peroxidases in resistance to P. truncatus in mature maize kernels and germs. Susceptibility of maize kernels and germ tissues to P. truncatus was evaluated and compared with soluble protein concentration and peroxidase activity in the germ. Additionally, a proteomic approach was employed to identify candidate peroxidases and other proteins potentially involved in resistance mechanisms. Results revealed a significant negative correlation between susceptibility traits in maize kernels and peroxidase activity in the germ, as well as a similar correlation between these traits and soluble protein concentration. These findings suggest that peroxidase activity and soluble protein accumulation in the germ likely play an important role in kernel resistance. Despite previous reports of some genotypes exhibiting low germ damage after insect interaction, all germ samples in this study showed relatively high levels of damage, regardless of genotype. Therefore, germ tissue does not exhibit any antixenosis effect. Further research is recommended to evaluate protein candidates in the germ and kernel contributing to resistance during storage.
- Tocopherol contribution to the resistance against storage pest Prostephanus truncatus in maize(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2024-12-02) Aguirre Espinoza, Carlos; García Lara, Silverio; emimmayorquin; Mora Vásquez, Soledad; School of Engineering and Sciences; Campus Monterrey; Gonzalez Rodriguez, America TzitzikiProstephanus truncatus infestation can cause losses as high as 80% on stored maize. Sources of resistance against this pest are related to the antioxidant capacity of the pericarp and aleurone layer structures, mainly due to phenolic acids content and their derivatives. Nonetheless, there is not enough information about the germ structure or the liposoluble antioxidants, such as tocopherols. To determine the contribution of tocopherols and liposoluble antioxidant capacity to the resistance against P. truncatus, thirteen genotypes of maize were tested in two confined bioassays (n=3). The first was to assess the susceptibility of each genotype. The second was with the enriched structure of the germ to gather information on damage and development of P. truncatus on this structure. Seven susceptibility parameters were recorded 7 and 60 days after infestation, and ten genotypes were selected based on a Susceptibility Selection Index, with five recognized as resistant and five as susceptible. HPLC-FLD was used to determine the content of tocopherols (δT, γT, and αT), and an ORAC assay was performed to measure the lipophilic antioxidant capacity among the ten genotypes selected. All Population 84 genotypes exhibited less damage by P. truncatus and were categorized as resistant. Three Population 84 genotypes were selected: P84C0Y (SI = 0.17), P84C4W (SI = 0.27; highest tocopherol content, 39.58 mg/kg; high L-AC, 429.04 μmol TE/g), and P84C4Y (SI = 0.51). Two selected genotypes previously recognized as susceptible were classified as resistant: Pink Creole (SI = 0.39; high tocopherol content 39.40 mg/kg; highest L-AC, 488.30 μmol TE/g) and Don Goyo (SI = 0.55). The most susceptible genotype was Red Creole (SI = 3.56; lowest L-AC, 205.48 μmol TE/g), the remaining 4 susceptible varieties selected were Peru2 (SI = 1.23), NAYA29B (SI = 1.07), Panchito (SI = 1.00; lowest tocopherol content, 11.21 mg/kg; low L-AC, 250.4 μmol TE/g), and Pozolero (SI = 0.97). Additionally, a strong correlation (p > 0.01) demonstrated that a short-length bioassay (7 days) can be comparable to a full-length bioassay (60 days). Both can measure a genotype susceptibility to P. truncatus based on weight loss, but only a full-length bioassay can provide information on adult emergence.
- Bioactivity on in vitro systems from peptides derived from scorpion venom(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2022) Rivera Aboytes, Elizabeth; García Lara, Silverio; emipsanchez; Castorena Torres, Fabiola; School of engineering and sciences; Campus Monterrey; Puente Garza, César ArmandoCancer is a pervasive global health challenge, compounded by the limitations of existing chemotherapeutic agents. These treatments frequently encounter obstacles when administered, necessitating exploration into alternative therapeutic approaches. Animal venoms, including those sourced from scorpions, have emerged as promising candidates for novel cancer therapies due to their distinct bioactive properties. Scorpion venoms have demonstrated efficacy against various cancerous processes, providing a valuable foundation for the development of adjunct therapies targeting hormone- dependent cancers such as breast and prostate cancer. In this study, two peptides were designed based on the consensus sequence of scorpion venom. Additionally, in silico analysis was utilized to predict crucial peptide characteristics, guiding subsequent synthesis and evaluation of bioactivity. These peptides underwent rigorous in vitro experimentation using cancer cell lines, notably MDA-MB-231 for breast cancer and PC3 for prostate cancer. Among the tested peptides KV7 exhibited notably promising results, demonstrating favorable cytotoxicity against both MDA-MB-231 and PC3 cells. However, it was observed that KV8 displayed cytotoxicity towards HDFa cells, indicating the imperative need for further refinement to minimize off-target effects and enhance specificity. While these findings suggest the potential of scorpion venom-derived peptides as adjunct therapies for hormone-dependent cancers, further research is imperative to fully elucidate their therapeutic mechanisms and optimize their efficacy. Continued investigation into innovative cancer treatments is paramount to address the unmet medical needs of patients worldwide. This provides insights into the exploration of scorpion venom derived peptides as a promising source of novel cancer therapeutics. Leveraging the unique properties of scorpion venoms, researchers may develop more effective and targeted treatments for hormone-dependent cancers, thereby improving patient outcomes and quality of life. This research underscores the importance of interdisciplinary approaches in the ongoing battle against cancer, highlighting the potential of nature-derived compounds to revolutionize cancer treatment strategies.
- Contribution of the maize germ (Zea mays L.) to the resistance to the postharvest pests Sitophilus zeamais and Prostephanus truncatus.(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2020-06-12) González Leyzaola, Alán; GARCIA LARA, SILVERIO; 123152; García Lara, Silverio; lagdtorre, emipsanchez; Winkler, Robert; Escuela de Ingeniería y Ciencias; Campus Monterrey; López Castillo, Laura MargaritaMaize (Zea Mays L.) is the most important cereal in terms of production. The maize weevil (Sitophilus zeamais) and the large grain borer (Prostephanus truncatus) are the two main postharvest insect pests that affect maize, causing losses as high as 80%. Factors attributed to resistance of maize kernels against insect pests have been widely studied in kernel structures such as pericarp, aleurone layer and endosperm. However, one structure that hasn’t been studied in this area is the germ. The aim of this study was to evaluate the contribution of the maize germ to the resistance to the attack of the postharvest insect pests S. zeamais and P. truncatus. For this purpose, we performed kernel-insect interaction assays with a duration of 60 days, testing both postharvest pests and 14 maize genotypes. For this work, we considered whole kernels and the hand-dissected germ. We recorded the main suceptibility parameters: grain weight loss, mortality rate, adult progeny and the mean development time of the pests. In order to define a group of possible metabolites which could be implicated in this resistance, we evaluated the chromatographic profiles (HPLC-DAD) of the 14 genotypes in term of phenolic compounds, in free and bound forms. We also evaluated the profile of tocopherols, phytosterols and fatty acids. Finally, we established the correlation between the susceptibility parameters determined in the insect bioassays and the evaluated compounds. Surprisingly, in the maize germ assays, although oviposition was observed after 60 days, there was no evidence of adult or larvae emergence of both pests. Furthermore, oleic acid showed a positive correlation with germ weight loss in both insect pests, while palmitic acid had a negative correlation of this parameter only in P. truncatus. Statistical differences in concentration of compounds from basal state and infested samples were detected in free and bound phenolics and liposoluble compounds. These findings provide strong evidence of an important contribution of the maize germ in the resistance against S. zeamais and P. truncatus by possible detrimental effects on early stages of development. This information could be helpful in the development of new strategies for the protection of maize kernels against S. zeamais and P. truncatus.
- Phytochemical and Nutraceutical Profiles of Blue Maize (Zea Mays) Hybrids Evaluated in Two Locations-Edición Única(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2010-12-01) Urías Peradlí, Marcos; Serna Saldívar, Sergio Othón; García Lara, Silverio; Gutiérrez Uribe, Janet Alejandra; Ramos Parra, Perla Azucena; Tecnológico de Monterrey, Campus MonterreyRecent years have seen an increased interest in blue maize (Zea mays) due to its proven nutraceutical properties. In recent times blue maize hybrids have been developed through a landrace starting point and by genetic improvement. These hybrids are being evaluated for their environmental stability and agronomic profile. With this objective, 25 promising hybrid blue maize crosses were selected from the improvement program at INIFAP-Bajío and planted in 2 contrasting environments located in the Bajío area and Morelia. The objective of this work was to evaluate the phytochemical and nutraceutical profiles of these hybrids and to select those with the best features. An initial bulk analysis was elaborated to elucidate any significant differences between both locations. Free and bound phenolic acids were evaluated using the Folin-Ciocalteu method as were their antioxidant capacity using the Oxygen Radical Absorbance Capacity (ORAC) method. Bound ferulic acid content was determined by High Pressure Liquid Chromatography (HPLC) and total monomeric anthocyanin content was determined by the pH differential method. Soluble carbohydrates, protein methods and biophysical properties like kernel color and endosperm texture were also determined. The results indicate a significant difference among the 25 genotypes evaluated. With a number of genotypes having free and bound phenolic acids content higher than those previously reported; their respective antioxidant capacities also showed high levels. Bound phenolic acid showed a significant difference between environments whereas anthocyanins were not affected by the environment. Soluble carbohydrate and soluble protein determination confirmed that white maize conversion retains key phytochemical properties. Results show a surprising correlation between chroma and anthocyanin content as well as for other kernel color measurements. Overall, the 25 hybrid blue maize genotypes evaluated were little influenced by the environment and retained high levels of health promoting phytochemicals and nutraceutical activity. A number of genotypes exhibited high phytochemical and nutraceutical profiles that can be used as a basis for crop improvement in further studies involving breeding blue maize. Especially genotype 22 which showed stability among regions and across most phytochemical traits, having high anthocyanin content, ferulic acid and antioxidant capacity.
- Modifications on physical, chemical, functional and nutraceutical properties in soft blue maize (Zea mays L.) after parboiling treatment and its impact on resistance to Prostephanus truncatus(Instituto Tecnológico y de Estudios Superiores de Monterrey) Morera Sánchez, Mariann; García Lara, Silverio; Espinosa Ramírez, Johanan del Pino; Bioingeniería; Bioingeniería; Campus Monterrey; López Castillo, Laura MargaritaMexico is the center of origin and diversification of maize (Zea mays L.). However, in this country, efforts have been focused on obtaining white corn over other varieties, such as pigmented ones. Although, pigmented varieties have recently received increased attention due to their nutraceutical properties, they tend to present kernels with floury endosperm. Therefore, efforts have been made in order to improve their physical features, by increasing the ratio of the hard endosperm and kernel hardness, mainly by genetical breeding without satisfactory results. In this way, the application of a hydrothermal treatment, such as parboiling, could serve as an approach to improve the quality of these maize varieties. Thus, the objective of this work was to evaluate the modifications in soft blue maize due to parboiling treatments in its physical, functional, chemical and nutraceutical properties, as well as the resistance to Prostephanus truncatus. Therefore, 96 parboiling treatments were developed by testing different conditions for each parboiling phase: hydration, steaming and drying. Then, maize kernels were evaluated for physical properties (endosperm texture, recovery percentage, quality parameters), functional properties of starch (pasting profiles), macronutrient composition (proximal analyses of whole kernels and endosperm), nutraceutical modifications (total anthocyanin content, anthocyanin profile, antioxidant activity) and resistance to P. truncatus (susceptibility parameters and Dobie Index). Parboiling decrease the kernel integrity by induces changes in its physical appearance; however, it increases maize quality by increasing test weight, thousand kernel weight, decreasing flotation index and promoting the movement of pigments to the endosperm. It also modified the pasting properties, by decreasing the peak viscosity; promoted the enrichment of the endosperm by inducing the diffusion of lipids and minerals; and improved the nutraceutical properties by enhancing the antioxidant activity. Thus, the optimization and the proper implementation of this treatment could serve as an approach to improve the quality of other pigmented maize varieties in terms of their physical features, but also according to their nutritional and nutraceutical profile.
