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.
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- 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.
- Characterization of arbuscular mycorrhizal fungi and endophytic bacteria in mycorrhizal and non-mycorrhizal mutant maize by a metagenomics approach(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-12-15) Guerrero Peña, Naomi Jocelyn; PACHECO MOSCOA, ADRIANA; 274621; Pacheco Moscoa, Adriana; emipsanchez; Gradilla Hernández, Misael Sebastián; Díaz de la Garza, Rocío Isabel; Escuela de Ingeniería y Ciencias; Campus Monterrey; Senés Guerrero, CarolinaArbuscular mycorrhizal fungi (AMF) establish mutualistic symbiosis with almost 80% of all plants. AMF are widely used in agriculture because they offer a substitute to chemical biofertilizers as they can boost plant growth under non-ideal conditions. Maize is the most important commercial and cultural crop in Mexico. The common symbiosis pathway (CSP) is a well conserved molecular signaling pathway in all plants that can achieve mycorrhizal and rhizobia symbiosis, which starts with specific receptors that recognize each microorganism. Here, maize-associated AMF species and endophytic bacteria composition from two variants of maize, a mycorrhizal wild type and a non-mycorrhizal mutant type, were assessed by using high-throughput MiSeq-Illumina sequencing. Mutant maize did not possess the HUN gen, a CASTOR homologous gene, that is involved in the CSP by starting upstream Ca2+ oscillations and activating molecular signaling cascade. Composite root samples of wild type (n=9) and mutant maize (n=10) were used for microbial characterization. Mycorrhization was observed in all samples. A total of 22 AMF species were found with abundance >1%, and only 7 species were shared by both types of maize. Differences among AMF composition were observed, where mutant plants showed absence of the AMF generalist species Rhizophagus. Shannon and Chao1 diversity indexes were higher in mutant plants than wild type maize. Regarding endophytic bacteria, 137 and 135 amplicon sequence variants (AVS) were found in wild type and mutant maize, where 105 were shared by both treatments. Streptomyces and Bulkholderia were the most predominant among all samples. Streptomyces abundance suggest that this genus may play a main role in bacterial and AMF composition, as it is known for improving AMF germination and symbiosis due to its chitinase production. As mutation of HUN gene was not sufficient to block complete symbiosis between AMF and the plant, further characterization of downstream genes of the CSP in maize and field experimentation are required.
- Effect of germination with selenium in physical and chemical properties of nixtamalized maize (Zea mays L.) tortillas(Instituto Tecnológico y de Estudios Superiores de Monterrey, 2021-06) Dávila Vega, Juan Pablo; Serna Saldivar, Sergio Román Othón; 3598; Serna Saldívar, Sergio Román Othón; tolmquevedo, emipsanchez; Antunes Ricardo, Marilena; Escuela de Ingeniería y Ciencias; Campus Monterrey; Guardado Félix, DanielaMaize is one of the most consumed cereals worldwide, especially in Mexico where staple foods like tortillas play a crucial role in the daily caloric intake, meaning in some cases up to the 40% of total caloric consumption. It has been demonstrated that germination of kernels offer an alternative for the improvement of the bioavailability of key nutrients and the intake of novel compounds like selenium (Se). Se plays a crucial role in human physiology by taking part in the antioxidant enzymatic mechanism, which is highly related to the prevention of diseases like cancer. Cancer, a multifactorial disease is generally treated with chemotherapy, although this induces negative responses and side effects in the organisms. By that, the search for preventive nutraceutical foods or complementary diets have gained attention in the last years. The main objective of the present research was to evaluate the effects of germination in the presence of Se and nixtamalization in maize tortillas in their physical, and chemical properties, and macronutrient composition. Results showed that germination can generate optimal masas and tortillas without further negative effects as chemical, physical or functional properties. This research clearly indicate the feasibility of processing sprouted grain kernels in the presence of Se via traditional nixtamalization for the production of table tortillas. The Se-enriched tortillas had excellent properties and contained high levels of Se, which is known to prevent oxidative stress and cancer
- 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.
