Agave genera include slow-growing plants with cultural and economic roots dating back to pre-Columbian times in Mexico. Several species have a widespread presence in the country and are cultivated ...and/or used directly from the field to obtain various derived products. Agave salmiana is widely used in the region of the High Valleys of Apan, Hidalgo, Mexico. However, fungal diseases are causing considerable losses to Agave crops. For this reason, fungi strains from maguey plants from Apan, Hidalgo, with “Negrilla” disease symptoms were isolated and identified morphologically and molecularly. The results provide information on a new disease disseminated in A. salmiana plants, which causes symptoms such as black spots on the leaves due to pathogenic fungi of the genera Bipolaris. The morphological and molecular characterization located the phytopathogenic fungus as new isolates of Bipolaris zeae. Finally, the re-isolation of the causal agent of the disease was achieved in all pathogenicity tests, verifying that the symptoms observed in the maguey plants were caused by B. zeae, thus corroborating Koch’s postulates, and constituting the first report of this fungus as a pathogen of A. salmiana in Mexico.
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 (
≤ 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
, with respect to treatment T1 of 1.02 ± 0.01 t ha
, 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.
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.
Agave genera include slow-growing plants with cultural and economic roots dating back to pre-Columbian times in Mexico. Several species have a widespread presence in the country and are cultivated ...and/or used directly from the field to obtain various derived products. Agave salmiana is widely used in the region of the High Valleys of Apan, Hidalgo, Mexico. However, fungal diseases are causing considerable losses to Agave crops. For this reason, fungi strains from maguey plants from Apan, Hidalgo, with “Negrilla” disease symptoms were isolated and identified morphologically and molecularly. The results provide information on a new disease disseminated in A. salmiana plants, which causes symptoms such as black spots on the leaves due to pathogenic fungi of the genera Bipolaris. The morphological and molecular characterization located the phytopathogenic fungus as new isolates of Bipolaris zeae. Finally, the re-isolation of the causal agent of the disease was achieved in all pathogenicity tests, verifying that the symptoms observed in the maguey plants were caused by B. zeae, thus corroborating Koch’s postulates, and constituting the first report of this fungus as a pathogen of A. salmiana in Mexico.
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 μ
and saturation constant (Ks) were 0.0961 h
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.
ABSTRACT 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.
Mosquitoes are one of the most dangerous insects in the world for humanity. Over one million people worldwide die from mosquito-borne diseases every year. Mosquito vectored diseases include protozoan ...diseases, i.e., malaria, filarial diseases such as dog heartworm, and viral diseases such as dengue, encephalitis, and yellow fever. In addition, mosquitoes transmit several diseases and parasites that dogs and horses are very susceptible too. These include dog heartworm, West Nile virus (WNV), and eastern equine encephalitis (EEE). Since its discovery, chemical insecticides have represented the most widely method used to control mosquito-borne vectors. However, the effects of chemical insecticides on mosquito vector populations are usually transitory because vectors can rapidly develop resistance against them. Each insecticide triggers the selection of one or more mechanisms of resistance. These mechanisms include changes in the target site of action and metabolic detoxification among others.
Globally, corn is the most economically important crop, surpassing crops such as wheat, rice and barley. However, the presence of pathogenic fungi associated with corn, have favoured the appearance ...of diseases that cause economic loss. Therefore, the aim of the present study is to assess the efficacy of treatments in vitro and in vivo with Trichoderma asperellum in controlling the disease severity and the yield reduction in corn plants caused by Fusarium verticillioides and Ustilago maydis. In vitro confrontation experiments demonstrated the high antagonistic capacity of the T. asperellum strains, which is able to reduce the radial growth of the pathogen's colonies from 88.71% up to 100%. In the field experiments treatments 6 and 7, where T. asperellum was confronted with F. verticillioides and U. maydis, showed a significant reduction in the average damage of the disease by 8.3 ± 6.7 and 9.5 ± 3.0, and an increase in their grain yield by 4.43 ± 0.33 and 4.11 ± 0.15 t/ha, respectively. Similarly, the percentage of good ears of 66.75 ± 5.4 and 70.37 ± 5.4, obtained in treatments 6 and 7, was higher than those values obtained in treatments 2 and 3 without Trichoderma confrontation. These results indicate that the selected Trichoderma strains isolated from Zea mays could effectively control these phytopathogenic fungi in field.
Vanilla 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.
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