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Globally, corn is the most economically important crop, surpassing other cereals of economic importance. However, the tillage methods, monoculture and the abuse of synthetic agrochemicals used in Mexico have led to the loss of fertility and soil yield. In this sense, the application of alternative fertilization methods based on chemical fertilizer, organic matter and biofertilizer, applied alone or in combination, can stimulate the defense systems of corn plants and increase their yield. Therefore, in this research, some fertilization schemes were tested on purple corn plants of the Kculli race through the evaluation of some growth and yield variables, as well as the subsequent evaluation of the chemical characteristics of the corn grain produced in each fertilization scheme. The results indicate highly significant differences (p ≤ 0.05) between treatments, for the different growth and yield variables studied. Of all the fertilization schemes evaluated, treatment T7 obtained the best grain yield of 6.19 ± 0.07 t ha−1, with respect to treatment T1 of 1.02 ± 0.01 t ha−1, as well as the highest protein content and starch quality. Being clear the positive effect of the adequate contribution of the macro and micronutrients used exerts on the corn crop in each of the fertilization schemes studied. On the other hand, the analysis carried out on the grains was found within the values reported by other authors.

Las plantas del género Agave representan un recurso forestal no maderable valioso para la recuperación del suelo. La epidermis de sus pencas contiene múltiples estomas y está cubierta por una capa cuticular. En la actualidad presentan una enfermedad fúngica que se caracteriza por la existencia de manchas grises circulares sobre las pencas, que con el tiempo se tornan necróticas; y en ocasiones, dichas lesiones terminan por secar las pencas. El objetivo de este trabajo fue describir la relevancia de la capa cuticular durante la colonización del hongo causante de la negrilla en Agave salmiana ssp. salmiana. La capa cuticular tiene un grosor de 121 ± 2.8 mm. Se observó una distribución homogénea de los estomas y se determinó la densidad (22.67-27.67 estomas mm-2) y el índice estomático (10.61-14.15). Los estomas observados son de tipo tetracítico, el tamaño de los ostiolos de 57.9 mm ± 5 de largo y 23.75 mm ± 1.25 de ancho y células epidérmicas poligonales isodiamétricas. Los cortes transversales y paradermales muestran que las hifas y los apresorios fúngicos quedan restringidos al lado anverso de la capa cuticular, por lo cual se corrobora la importancia de conservar la epidermis en las pencas del maguey pulquero.

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espanolEl jugo de vainilla ha mostrado tener empiricamente actividad antifungica contra algunas cepas de hongos; sin embargo, no se tiene reportes contra el genero Alternaria. En este trabajo, se obtuvo el perfil quimico del jugo de vainilla y se probo su actividad antifungica contra cepas de hongos de la familia Pleosporaceae, aisladas de plantas enfermas de sorgo y cebada. Las cepas fueron identificadas como Alternaria alternata por sus caracteristicas morfologicas y moleculares. La caracterizacion del jugo de vainilla de vainas de Vanilla planifolia mostro la presencia de vainillina, acido vainillico, p-hidroxibenzaldehido, acido p-hidroxibenzoico, guaiacol, glucovainillina, alcohol vainillico y furfural. El jugo de vainilla tuvo un efecto fungistatico contra todas las cepas de A. alternata probadas en este estudio, aumento el tiempo de latencia de 50 a 112 h, y no se produjeron conidios. Este resultado indica la posible aplicacion del jugo de vainilla como una alternativa para controlar cultivos agricolas como la cebada y el sorgo en Mexico. EnglishVanilla juice has been shown empirically to have antifungal activity against some fungal strains; however, there are no activity reported against Alternaria genre. In this work, the chemical profile of vanilla juice was obtained and its antifungal activity against fungal strains from the family Pleosporaceae, isolated from sorghum- and barley-diseased plants, was tested. The strains were identified as Alternaria alternata by their molecular and morphological characteristics. The vanilla juice characterization from Vanilla planifolia pods showed the presence of vanillin, vanillic acid, p-hydroxybenzaldehyde, p-hydroxybenzoic acid, guaiacol, glucovanillin, vanillyl alcohol, and furfural. Vanilla juice showed a fungistatic effect against all A. alternata strains tested in this study and increased the lag time from 50 to 112 h, and no conidia were produced. This result indicates the possible application of vanilla juice as an alternative to control agricultural crops such as barley and sorghum in Mexico.

The main function of the diet is to provide the necessary nutrients to meet the nutritional needs of people. Since long, there is evidence that there is a relationship between diet and health and from these arose the concept of functional foods. In general, functional foods are those that not only fulfill a nutritional function but also contain biologically active components that offer health benefits and reduce the risk of suffering diseases. An important key to know the effect that functional foods have on nutrition is to determine how the body responds to the stimulation of these. In other words, the components of the diet can alter genomic expression. However, not all people respond in the same way. A large number of genes from the human genome are induced to code for the proteins involved in the nutritional processes and the induction of these genes is determined by the polymorphisms that each person has in their genome. For example, a diet rich in folic acid prevents the development of cardiovascular diseases related to people who have a polymorphism in exon 4 of the MTHFR gene related to folate metabolism. Therefore, the proposal of this book is to review the current research of Nutrigenomics, which is the study of the effect of nutrients on the expression of genes and Nutrigenetics which is the influence of polymorphisms of people in response to nutrients.

Introducción: Trypanosoma cruzi (T. cruzi), esta clasificado en seis linajes mediante marcadores moleculares de tipificación, que son fácilmente amplificados por técnicas de biología molecular. El objetivo del trabajo fue identificar y ubicar geográficamente a los aislados de T. cruzi que infectan naturalmente a los triatominas de los municipios del Estado de Hidalgo a través de la técnica de PCR, que amplifica fragmentos de la región intergénica del gen mini-exón. Método: Se recolectaron 170 muestras de insectos hematófagos en 14 municipios del Estado de Hidalgo, México. El diagnóstico de laboratorio en las muestras de heces y de tejido digestivo de los triatominos, se realizó de manera convencional por microscopia óptica y por la técnica de PCR para determinar la presencia o ausencia de T. cruzi y para la identificación del linaje correspondiente del parásito.Resultados: Se identificaron tres taxones de triatominos: Triatoma dimidiata (87/170), Triatoma mexicana (14/170) y Triatoma gerstaeckeri (7/170). En el 36.47% (62/170) de los especímenes colectados la especie no pudo ser identificada y se clasificaron únicamente como T. spp. Se determinó la presencia del parásito en el 1.76% de los vectores analizados por el método parasitoscópico y en el 11.17% por el método de biología molecular. El total de los parásitos analizados corresponde al biotipo TcI de T. cruzi. En el ecotopo peridoméstico, se encontró la mayor abundancia de triatominos (80.58%) y el mayor porcentaje (10.58%) de infección por T. cruzi.Conclusiones: El vector más importante encontrado en la región en estudio fue Triatoma dimidiata seguido de T. mexicana y T. gerstaekeri y el biotipo con el que están mayormente infectados es el TcI. Los triatominos encontrados se distribuían principalmente en hábitats peridomésticos en los municipios estudiados. Los resultados indican la existencia de riesgo de infección para los habitantes de esas regiones endémicas del Estado de Hidalgo, México.

Cepas de Cladosporium aisladas de frutos de Theobroma cacao e identificadas como C. cladosporioides se confrontaron contra Trichoderma harzianum VSL291 por medio de experimentos de confrontación. El Índice de Biocontrol (IBC) de T. harzianum VSL291 sobre C. cladosporioides observado a los siete días fue de 76,29%. Las mayores actividades proteolíticas detectadas en la cepa antagonista con paredes celulares de C. cladosporioides, Colletotrichum gloeosporioides y Corynespora cassicola se asociaron con un aumento de las actividades de las enzimas β-1,3 glucanasas, quitinasas, lipasas, proteasas y xilanasas. Estos resultados sugieren que las enzimas proteolíticas de acuerdo a su grado de inducción podrían participar en el efecto antagonista de T. harzianum VSL291 contra los hongos confrontados. Por otra parte, los valores más altos del IBC sugieren que las cepas de Trichoderma podrían tener la capacidad para antagonizar de manera más eficiente contra los patógenos fúngicos de este cultivo. Finalmente, se desarrolló un modelo cinético no estructurado bajo un sistema de ecuaciones diferenciales acopladas en función del tiempo basado en el mecanismo del micoparasitismo. Este modelo predice las concentraciones de las actividades enzimáticas de Trichoderma (β-1,3 glucanasas, quitinasas, lipasas, proteasas, xilanasas) con las paredes celulares de C. cladosporioides. Los parámetros cinéticos se ajustaron a los datos experimentales y se validaron por un coeficiente de correlación.

The genus Aspergillus has been isolated from cocoa plantations worldwide. However, there is not enough information about its role in the occurrence of diseases. Aspergillus niger strains were characterized by morphological and molecular techniques. The sequences of A. niger were deposited in the GenBank databases. In addition, the antagonistic effect of Trichoderma asperellum VSL80 against A. niger strains was evaluated, obtaining a biocontrol index (BCI) between 15.36 and 88.71%. Scanning electron microscopy showed that the Trichoderma hyphae grew in parallel with the hyphae of A. niger and, in some cases, they were found together with the hyphae of the pathogenic fungus preventing their development. On the other hand, the maximum enzymatic activity of xylanases produced by A. niger in submerged culture was 1.128 U mL1 at 96 h. The morphological and molecular characterization of A. niger strains confirms its presence in Mexico. In addition, information obtained of the BCI may be important for the development of strategies for the prevention and control of this fungus. The enzymatic activity of A. niger during mycoparasitism by T. asperellum could explain the low BCI observed in some A. niger strains confronted with T. asperellum. Finally, the xylanolytic enzyme production by A. niger indicated that this fungus could be used in the industry to obtain xylanases.

The aim of this paper is to study the stability, controllability and observability for a bioethanol production dynamic system. Likewise, a novel model based on the mechanism of multiple parallel coupled reactions was used to describe the kinetics of substrate, enzyme, and biomass and product formation. This model has been extended to continuous operation, which is employed as a virtual plant to enable the implementation of the properties. The maximum ethanol production conditions are obtained by manipulating the dilution rate with an optimal initial substrate concentration. A nonlinear observer is implemented to show the results of the observability analysis. Sufficient and necessary conditions for state controllability and state observability of such system are established. Results indicated that the proposed model can be applied as a way of augmenting bioethanol production, controlling and monitoring the process.

Ethanol was produced using mucilage juice residues from processed cocoa with Pichia kudriavzevii in batch fermentation. Experimental results showed that maximum ethanol concentration was 13.8 g/L, ethanol yield was 0.50 g-ethanol/g glucose with a productivity of 0.25 g/L h. Likewise, a novel phenomenological model based on the mechanism of multiple parallel coupled reactions was used to describe the kinetics of substrate, enzyme, biomass and product formation. Model parameters were optimized by applying the Levenberg-Marquardt approach. Analysis of results was based on statistical metrics (such as confidence interval), sensitivity and by comparing calculated curves with the experimental data (residual plots). The efficacy of the proposed mathematical model was statistically evaluated using the dimensionless coefficient for efficiency. Results indicated that the proposed model can be applied as a way of augmenting bioethanol production from laboratory scale up to semi-pilot scale.

Traditional Mexican cocoa fermentation performed in batch was studied by applying kinetic modelling with experimental validation. Similar microbiological behaviour was observed up to 60 h, with a temperature increase at 72 h that remained constant (50 °C) until 156 h. Metabolite-production kinetics (ethanol and acetic acid) from degradable mucilage (glucose) was explored. Exploration involved applying different combinations of unstructured growth models, in order to consider the effect of temperature when predicting the concentration of metabolites in these microorganisms. Two methods were used to optimize model parameters: the Levenberg–Marquardt optimization approach and Genetic Algorithms (GAs). GAs which could be used to scale up the fermentation process indicated the applicability of this model for predicting fermentation quality. The maximum specific rate average for μmax and saturation constant (Ks) were 0.0961 h−1 and 1.4 mg/g m.s., respectively. The results obtained indicate the expediency of this technique for future application in the design and control of batch fermentation.

A Hypocrea/Trichoderma strain was isolated from cacao (Theobroma cacao L.) pods from a cacao plantation in Huimanguillo, Tabasco, Mexico. The strain was identified as H./T. viridescens ITV43 by its morphological characteristics and DNA sequence analysis of ITS1-5.8s-ITS2 and was tested against Moniliophthora roreri Cif & Par and Phytophthora strains by confrontation experiments. The biocontrol of H./T. viridescens ITV43 measured as biocontrol index (BCI) at seven days against M. roreri(HT-ITV01, HT-ITV20, HT-ITV27), P. megasperma (HT-ITV08, HT-ITV15, HT-ITV37) and P. capsici (HT-ITV14, HT-ITV16, HT-ITV33) strains ranged from 78.28-81.63, 63.04-69.95 and 69.77-76.31%, respectively. After 31 days of incubation, the BCI values increased to 81.52-86.50 for M. roreri and 100% for Phythopthora strains. Samples taken from the interaction zone were observed by optical and scanning electron microscopy. The results show the effect of H./T. viridescens ITV43 strain on morphological deformations and disorganization of the M. roreri and Phytophthora cell wall structures. Highest BCI values obtained suggest that the Hypocrea strains isolated from T. cocoa could have the ability to antagonize more efficiently against fungal pathogens of this crop. Key words: Antagonism, Hypocrea, mycoparasitism, Moniliophthora, Phytophthora, Theobroma.

Scyphophorus acupunctatus Gyllenhal (Coleoptera: Dryophthoridae), which also is known as agave weevil, is distributed across 5 continents. In Mexico, their presence has been reported in 12 states. Many species of Agave (Asparagaceae) are suitable hosts, though not all are equally suitable. Plant infestation can start with either female or male weevils, and their presence can be detected by gummy secretions emanating from feeding sites. The punctures are observed principally in the lower part of the trunk and external roots of the infested plants. Eggs are deposited singly or in clusters of up to 4 eggs at the feeding punctures after tissue decay has begun. The eggs hatch after about 5 d, and young larvae begin to create tunnels in the plant tissue. The larvae display 11 instars, and require about 50 to 90 d for development. The pupae normally require 11 to 14 d. The life cycle lasts between 105 to 137 d depending on the agave species with which the weevil is associated. The active insect can attack during any mo of the yr, although it is more frequent in the rainy season. Scyphophorus acupunctatus dispersion is determined by the attraction of volatile agave compounds. This insect apparently introduces different microorganisms that have been associated with the agave maladies. Plant extracts and seed powders have been assessed as potential botanical insecticides on larvae and pupae, with plant extracts causing mortality of 43 to 53% in larvae and 3 to 15% in pupae, and with seed powders causing 90 to 100% larval mortality. Synthetic insecticides have not been successful because the larvae and adults live inside the plant tissues. Alternative effective control tactics are needed to avoid increased damage and destruction of this important crop.

During traditional cocoa processing, the end of fermentation is empirically determined by the workers; consequently, a high variability on the quality of fermented cocoa beans is observed. Some physicochemical properties (such as fermentation index) have been used to measure the degree of fermentation and changes in quality, but only after the fermentation process has concluded, using dried cocoa beans. This would suggest that it is necessary to establish a relationship between the chemical changes inside the cocoa bean and the fermentation conditions during the fermentation in order to standardize the process.Cocoa beans were traditionally fermented inside wooden boxes, sampled every 24 h and analyzed to evaluate fermentation changes in complete bean, cotyledon and dried beans. The value of the fermentation index suggested as the minimal adequate (≥1) was observed at 72 h in all bean parts analyzed. At this time, values of pH, spectral absorption, total protein hydrolysis and vicilin-class globulins of fermented beans suggested that they were well fermented.Since no difference was found between the types of samples, the pH value could be used as a first indicator of the end of the fermentation and confirmed by evaluation of the fermentation index using undried samples, during the process.

Acetic acid bacteria (AAB) from traditional indigenous process of cocoa bean fermentation were studied at a location in Huimanguillo, Tabasco, Mexico. High counts were detected at the beginning of the fermentation (5.7+ or - 0.26 cfu/g dry matter) and were present throughout fermentation time. Six AAB strains were isolated and characterized by morphological, biochemical and molecular methods. Morphological and biochemical methods were inconclusive for final identification of bacteria. However, the amplification of16S rDNA of the strains by polymerase chain reaction (PCR) and the Blast analysis of the obtained nucleotide sequences showed homology (99 to 100%) with Acetobacter tropicalis. Because the production of acetic acid is an important factor in the development of chocolate flavour precursors we studied the capacities of the strains to produce acetic acid. A. tropicalis ITV61 reached 2.5% (v/v) acetic acid production in 9-h on potato broth medium supplemented with ethanol (4% v/v) while the others A. tropicalis strains accumulated low acetic acid concentrations (> 0.2%). A. tropicalis ITV61 strain was able to grow at 4, and 7% ethanol. Tolerance of the strain A. tropicalis ITV61 to acetic acid is not affected at concentrations of 1% from the beginning of fermentation. Key words: Acetobacter, cocoa, fermentation, isolation, molecular characterization.