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Estudio de la actividad enzimática digestiva de la langosta de agua dulce Cherax quadricarinatus (Decapoda, parastacidae)

SILVERIO LOPEZ LOPEZ (2004)

Una de las especies de crustáceos que en los últimos 10 años ha despertado el interés en los acuacultores es la langosta de agua dulce o acocil, Cherax quadricarinatus, especie de Australia que se introdujo a México en los noventas. Esta especie tiene un cultivo relativamente sencillo, a pesar de ello, el aspecto de nutrición no se conoce bien aún. En la acuacultura la alimentación es uno de los factores de mayor preocupación para el productor, además de ser uno de los rubros mas costosos de la producción. El aporte adecuado de nutrientes asegura un buen crecimiento y salud a los organismos, sin embargo, para lograr esto debe tomarse en cuenta que cada organismo tiene diferentes necesidades nutricionales, así como distintas capacidades para asimilar el alimento. Por esta razón, si conocemos estas capacidades, podremos proporcionar el alimento más adecuado y reducir gastos en el cultivo de los organismos. Se hizo un estudio sobre la actividad enzimática digestiva en juveniles de la especie Cherax quadricarinatus. Se evaluó, mediante bioensayos la respuesta enzimática digestiva de los organismos después de someterlos a diferentes tratamientos. El primer ensayo consistió en la elaboración de siete alimentos artificiales, utilizando distintas harinas de origen animal y vegetal (calamar, langostilla, pescado, sorgo, soya y trigo) sustituyendo un 15% de este ingrediente en un alimento basal de referencia, con el propósito de observar la respuesta enzimática digestiva. De los alimentos probados, los que tuvieron un mayor porcentaje de inclusión de harinas de pescado (60% PC), sorgo y trigo favorecieron el crecimiento. No se encontró una correlación entre el crecimiento y la actividad enzimática digestiva. El segundo ensayo consistió en proporcionar siete alimentos con diferente nivel de proteína (20, 26, 32, 38, 44, 50 y 56%). Se encontró que el alimento con 32% de proteína produjo la mas alta TCR. La respuesta enzimática proteolítica total fue mayor para los organismos que recibieron los alimentos con 26, 32, 38 y 44 y 50% de proteína al final del experimento. Altos niveles de proteína en el alimento redujo la actividad proteolítica. La actividad amilasa se redujo al final del experimento, pero la actividad lipasa aumento para el mismo periodo [...]

In the last ten years, one freshwater species of crustacean that has generated interest in aquaculture is the freshwater crayfish, Cherax quadricarinatus, from Australia that was introduced to Mexico in nineties. This species has a relatively simple culture. However, aspect of nutrition are not well known. In aquaculture feeding is one of the factors of great interest to producers, and one of the more expensive aspects of production. A suitable supply of nutrients assures good growth and health to the organism; nevertheless, to obtain this, optimal nutritional requirements and capacity to assimilate feed need to be investigated. A study of digestive enzymatic activity in juvenile Cherax quadricarinatus was undertaken. By means of bioassays digestive enzymatic response was evaluated under different treatments. The first experiment consisted of measuring the results of seven artificial diets, using different meals of animal and vegetable origin (squid, red crab, fish, sorghum, soy and wheat) replacing 15% of these ingredients in a basical diet of reference to observe digestive enzyme responses. Relative Growth Rate was greater in crayfish fed with high carbohydrate content diets. Diets with fish meal (60%), and sorghum and wheat meal improve growth. However, there was no correlation between growth and digestive enzyme activity. The second experiment consisted of providing seven diets with different protein level (20, 26, 32, 38, 44, 50 and 56%). The diet with 32% protein produced the highest Relative Growth Rate. Proteolytic activity was greater for diets with 26, 32, 38, 44 and 50% protein by the end of the experiment. Higher protein levels in the diet reduced proteolytic activity. Amylase activity diminished at the end of the experiment, but lipase activity increased during the same period [...]

Doctoral thesis

Crustaceans; Cherax; digestive enzymes BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) FISIOLOGÍA ANIMAL

Biológia y cultivo de la cabrilla sardinera Mycteroperca rosacea: desarrollo larvario, ontogenia digestiva y contribución a la optimización del cultivo larvario

ROBERTO ALEXANDER MARTÍNEZ LAGOS (2009)

"La cabrilla sardinera, Mycteroperca rosacea es una especie endémica del Pacífico mexicano que tiene importancia en la pesca comercial, deportiva y además cuenta con un alto potencial en la acuicultura. Esta especie ha sido investigada, en los últimos años, obteniéndose avances significativos en el conocimiento de la biología como en la zootecnia de cultivo. Una vez analizados estos logros científicos y tecnológicos, se determinaron los objetivos de esta Tesis: estudiar las características morfológicas de la especie durante su desarrollo larval, determinar el desarrollo estructural del sistema digestivo y determinar la actividad de las enzimas digestivas durante el desarrollo larvario. Determinar el efecto del tipo y densidad del alimento proporcionado a las larvas en su primera alimentación sobre el crecimiento y la supervivencia. De la misma forma, se analizó el efecto de la intensidad de luz en las larvas en su primera alimentación. El estudio del primer objetivo tuvo como resultado la división del periodo larvario, que duró 60 días a una temperatura de 25 ±1°C, en 8 estadios de desarrollo de acuerdo a las diferentes características morfológicas que presentan las larvas durante su metamorfosis, destacando, la apertura de la boca al tercer día posterior a la eclosión (DPE), la aparición de las espinas extendidas en las aletas pélvicas y dorsal a los 10 DPE, la flexión del notocordio a los 25 DPE, la desaparición de las espinas extendidas de las aletas pélvicas y dorsal entre los 45 y 50 DPE. El crecimiento de las diferentes estructuras corporales analizadas durante el desarrollo larvario fue alométrico con respecto a la longitud total de la larva y mostró dos fases, con un punto de inflexión, que cambio de un crecimiento alométrico negativo en la primera etapa de la metamorfosis, del 1 a los 34 DPE a un crecimiento positivo entre los 35 y 40 DPE, lo que nos indica el desarrollo de una mayor capacidad de las larvas como predadores activos en este segundo periodo y en la primera parte de su desarrollo estos organismos son predadores de oportunidad. Al analizar el tamaño de la boca de las larvas durante su desarrollo larval, se determinó que los rotíferos no son el alimento más apropiado para las larvas de cabrilla sardinera en la primera alimentación. Ya que este tipo de alimento puede ser demasiado grande para las larvas de esta especie..."

"The leopard grouper, Mycteroperca rosacea, is an endemic species of the Mexican Pacific coast with commercial and sport fishing relevance and with high potential for aquaculture. This species has been investigated in recent years and has yielded significant advances in our understanding of its biology as well as aquatic husbandry. After analyses of these recent scientific and technological achievements, the objectives of this thesis were identified: (1) to study the morphological characteristics of the species during their larval development, (2) to determine the structural development of the digestive system (3) determine the activity of digestive enzymes and finally (4) to determine the effect of type and density of the food provided to larvae in their first feeding on growth and survival. In addition, we also analyzed the effect of light intensity on first feeding of larvae. Results of the study's first objective indicate that the larval division period, lasted 60 days at a temperature of 25 ± 1 ° C, and included 8 stages of development according to the different morphological characteristics presented by the larvae during metamorphosis. Mouth opening occurred on the third day after hatching (DAH), the appearance of extended spines in dorsal and pelvic fins at 10 DAH, notochord flexion at 25 DAH, the disappearance of the extended spines pelvic and dorsal fins from 45 to 50 DAH. The growth of the various structures analyzed was allometric with respect to the total length of the larva and showed two phases with an inflection point, which presented negative allometric growth in the first stage of metamorphosis from the first DAH to 34 DAH and changed to positive growth between 35 and 40 DAH, which indicates the development of enhanced capacity of the larvae to function as active predators in this second period, while during the first stage of their development these organisms are simply predators of opportunity. By analyzing the size of the mouth of the larvae during their larval development we determined that rotifers are not suitable food for grouper larvae at first feeding. Since this type of food may be too large for the larvae of this species. It was determined that the period for beginning husbandry activities to avoid cannibalism is between 40 and 50 days of culture in this period because at this time the larvae reabsorb their spine of their extended dorsal and pelvic fins that protect them, in part, from potential predators..."

Doctoral thesis

Mycteroperca rosacea, enzimas digestivas, desarrollo larvario digestive enzymes, larval development BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) DESARROLLO ANIMAL DESARROLLO ANIMAL

Effect of protein level in diet and feeding schedule on the digestive enzymatic activity of Macrobrachium tenellum juveniles

Luis Daniel Espinosa Chaurand olimpia victoria carrillo farnés FERNANDO VEGA VILLASANTE Héctor Gerardo Nolasco Soria (2019)

"This study assessed the effect of protein level in diet and feeding schedule on the digestive enzymatic activity of Macrobrachium tenellum juveniles. Freshwater prawn juveniles (0.31 ± 0.004 g and 32.48 ± 0.27 mm) were fed diets with 20, 25, 30, 35 and 40% crude protein (CP) (p/p). In a second experiment, feeding schedules were assessed at 08:00, 14:00 and 20:00 h with feed at 30% CP with juveniles of 0.22 ± 0.002 g and 29.36 ± 0.28 mm. In both experiments, five organisms were sampled after 60 days of treatment in a time-lapse of one hour (08:00 to 09:00 h) per experimental tank and treatment. The enzymatic extract was obtained from the complete organisms to determine specific general protease, trypsin, chymotrypsin, amylase and lipase activities. Greater general protease, trypsin and lipase activities were observed in feed at 40% CP. The feeding schedules with greater general protease, trypsin, lipase and amylase activities were found at 14:00 and 20:00 h. Chymotrypsin did not show differences among treatments at CP levels or feeding schedules. Protein level in diets for M. tenellum modified basal digestive enzymatic activity and increased proteolytic and lipolytic activities, while it decreased amylolytic activity as the inclusion of CP level increased in the diet; likewise, the activity was modified by feeding schedule, showing a direct correlation between the increase in digestive enzymatic activity and food offering at the end of the day."

Article

Macrobrachium tenellum, prawn, feeding schedule, digestive enzymes, digestive physiology CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA CIENCIAS AGRARIAS PRODUCCIÓN ANIMAL NUTRICIÓN NUTRICIÓN

Contribución del biofloc inoculado con diferentes probiótico sobre el crecimiento y niveles de actividad enzimática digestiva en juveniles de tilapia (Oreochromis niloticus Var SPRING)

Contribution of biofloc inoculated with different probiotics on the growth and levels of digestive enzymatic activity in juvenile tilapia (Oreochromis niloticus Var SPRING)

VLADIMIR NICOLAS MUÑOZ KUEHNE (2018)

El presente estudio evaluó la actividad enzimática intestinal de tilapia del Nilo (Oreochromis niloticus var SPRING) cultivada en tanques con tecnología biofloc (BFT) inoculados con probióticos comerciales. Cuatrotratamientos con biofloc, un control negativo y un control positivo se manejaron en tanques al aire librede 310L: los tratamientos con BFT inoculado con el probiótico comercial Eco-aquablend® por cuatro (T1)y ocho semanas (T2). Así mismo, el probiótico comercial Eco-aquaprotect® se inoculo por cuatro (T3) yocho semanas (T4), el control negativo uso agua limpia (C-) sin biofloc, con recambios de agua del 20%diario; el control positivo (C +) uso biofloc pero no se agregó probiótico. Todos los tanques fueronalimentados con 32% de proteína y 06% de lípidos. Cada tanque contenía 30 peces con un peso inicial de 11,66 g ± 2,43 g. La relación de alimentación se ajustó de 6 a 2% de la biomasa total, los peces fueronalimentados 2 veces al día. Se agregó harina de maíz y melaza en los tanques BFT para mantener unarelación C: N la cual se fue modificando de 20: 1 a 10: 1 a lo largo del experimento. El sólido suspendidototal (TSS) se mantuvo en alrededor de 50 mg l-1 en tanques de BFT. Las enzimas leucina aminopeptidasa, quimotripsina, tripsina, proteasas alcalinas totales, fosfatasa y a-amilasa fueron evaluadas en intestinosde tilapia del Nilo utilizando sustratos específicos para cada enzima. Las tilapias criadas en BFT mostraronun mejor rendimiento de crecimiento. La supervivencia de los peces fue del 96%. La producción neta debiomasa fue un 43% más alta que en los tanques de control negativo, lo que confirma la utilización de biofloc por los peces como alimento. No hubo diferencia en el crecimiento / producción de peces entreT1, T2, T3 y C+. El crecimiento fue significativamente mayor para T4 (P <0.05). No se encontrarondiferencias significativas en las concentraciones de amonio, nitrito y nitrato entre los tratamientos. T4 mostró una mayor actividad en tripsina, quimotripsina, fosfatasa y a-amilasa; para las proteasas alcalinas totales, la mayor actividad fue para T1, T2 y T4, sin encontrar diferencias significativas entre estostratamientos. El control negativo mostró la mejor actividad enzimática para Leucina. El uso del probióticocomercial (Eco-aquablend®) durante ocho semanas en un sistema BFT parece aumentar la producción devarias enzimas intestinales. Por lo tanto, la energía metabólica se usó de manera más eficiente paraaumentar el crecimiento en

The present study evaluated the intestinal enzymatic activity of Nile tilapia (Oreochromis niloticus) cultured in tanks with biofloc technology (BFT) innoculated with commercial probiotics. Four biofloc treatments, a negative and a positive control were managed in 310L outdoor tanks: BFT with a commercial probiotic (Ecoaquablend®) for four (T1) and eight weeks (T2); BFT with a comercial probiotic (Eco-aquaprotect®) for four (T3) and eight weeks (T4), and clean wáter negative control (C-) with no biofloc and wáter Exchange of 20% daily; positive control (C+) with biofloc bu noprobiotic was added (Table 1). All tanks where fed with 32% crude protein and 06% lipids. Each tank contained 30 fish with an initial weight of 11.66 g ± 2.43g.Feeding ratio was adjusted from 6 to 2% of the total fish biomass daily in each tank. Cornmeal and molasses where added in BFT tanks to maintain a C:N ratio from 20:1 to 10:1. The total suspended solid (TSS) was maintained at around 50 mg l-1 in BFT tanks. Leucine aminopeptidase, chymotrypsin, trypsin, total alkaline proteases, phosphatase and a-amylase enzymes where evaluated from intestines of Tilapia using specific substrates for each enzyme. Tilapias reared in BFT showed better growth performance. Fish survival was 96%. Net fish production was 43% higher in BFT tanks than in the negative control tanks confirming the utilization of biofloc by fish as food. There was no difference in fish growth/production among T1, T2, T3 and C+. Growth was significantly higher for T4 (P<0.05). No significant differences in ammonia, nitrite and nitrate where found among treatments. T4 showed higher activity in Trypsin, Chymotrypsin, Phosphatase and a-amylase; for total alkaline proteases, the higher activity were for T1, T2 and T4, with no differences among this treatments. Negative control showed the best enzymatic activity for Leucine. The use of the commercial probiotic (Eco-aquablend®) for eight weeks in BFT system seems to increase the production of several intestinal enzymes. Therefore, metabolic energy is used more efficiently to increase growth in tilapia reared in BFT inoculated with this product. Likewise, the cost-benefit was enhanced using this products on tilapia biofloc culture.

Master thesis

Enzimas digestivas, biofloc, probióticos, Oreochromis niloticus Digestive enzymes, biofloc, probiotics, Oreochromis niloticus BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) NUTRICIÓN

Use of Potato Starch in Diets of Tropical Gar (Atractosteus tropicus, Gill 1863) Larvae

CARLOS ALFONSO FRIAS QUINTANA CARLOS ALFONSO ALVAREZ GONZALEZ DARIEL TOVAR RAMIREZ RAFAEL MARTINEZ GARCIA SUSANA CAMARILLO COOP EMYR SAUL PEÑA MARIN MARIO ALBERTO GALAVIZ ESPINOZA (2017)

"Tropical gar, Atractosteus tropicus, is a carnivorous fish species from Southern México with high value and acceptance in local markets. Therefore, the present study aims to spare proteins in diets for larviculture of this species. An experiment was performed using three different experimental diets with increasing carbohydrate levels based on potato starch (S) and decreasing protein content (P) and total energy: 16% S (16% S–44% P), 22% S (22% S–40% P) and 28% S (28% S–36% P). Tropical gar larvae (five days post-hatching, 2.1 mm

average notochordal length) were assessed for growth, survival, degree of cannibalism, and digestive enzyme activities for 30 days. Highest growth and survival (24%), as well as the lowest cannibalism (33%), was seen in larvae fed the 28% S diet, and these larvae

also had the highest lipase, amylase and glucosidase activities (0.28, 0.56 and 0.11 units, respectively). Protease activity (alkaline protease, trypsin, chymotrypsin, and leucine aminopeptidase) was higher in the larvae fed the 22% S diet than in those given the 16% S and 28% S diets. In conclusion, dietary inclusion of potato starch at 28% S enhanced growth, survival and some digestive enzyme activities, and decreased cannibalism in the larval gar. Potato starch could replace dietary protein as a major source of energy for A. tropicus larvae, thereby reducing the cost of diets."

Article

growth, cannibalism, digestive enzymes, fish larvae, dietary carbohydrate, protein sparing BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOLOGÍA ANIMAL (ZOOLOGÍA) COMPORTAMIENTO ANIMAL

Roles enzimáticos asociados a la anatomía intestinal de la lombriz de tierra Eisenia fetida (Savigny, 1826)

Flor Berenice Ordoñez Arévalo (2016)

Resumen en español: "El objetivo del trabajo fue evaluar la dinámica enzimática a lo largo de la anatomía intestinal de Eisenia fetida (Oligochaeta, lumbricidae), para proponer las posibles vías catabólicas que pudieran actuar sobre los principales componentes de los residuos orgánicos durante el proceso de lombricompostaje. Para abordar el estudio se determinó la actividad de 19 enzimas hidrolíticas en tres diferentes secciones del tracto digestivo de Eisenia fetida (A, boca, molleja; B, intestino anterior; C, intestino intermedio y posterior) en periodo de ayuno, 24 horas, 30, 60 y 90 días, respectivamente; además del análisis químico proximal del sustrato en cada período. La información obtenida aporta al conocimiento de la fisiología digestiva de la lombriz adaptada a un clima tropical; tales como la correlación entre las máximas actividades de glicosilhidrolasas con la sección B (que concuerda con la disminución de hemicelulosa del sustrato) y la proteasa α- quimotripsina en la sección C. Esto puede ser de gran interés para el desarrollo de alternativas viables para problemas de contaminación (como el aprovechamiento de los residuos orgánicos); así como la bioprospección de enzimas de interés para aplicaciones biotecnológicas. "

Master thesis

Eisenia fetida;Eudrilus euginae;Lombrices de tierra;Tubo digestivo;Desechos orgánicos;Enzimas digestivas;Elaboración de vermicompost Eisenia foetida;Eudrilus euginae;Earthworms;Digestive tract;Organic wastes;Digestive enzymes;Vermicomposting BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA CIENCIAS DE LA VIDA

Effect of attractant stimuli, starvation period and food availability on digestive enzymes in the redclaw crayfish Cherax quadricarinatus (Parastacidae)

HECTOR GERARDO NOLASCO SORIA (2014)

"Chemical stimuli in crayfish have been extensively studied, especially in the context of social interactions, but also to a lesser extent in relation to food recognition and the physiological response of digestive enzymes. This is particularly important in commercial species in order to optimize the food supplied. The first objective of this study was to determine whether incorporation of squid meal (SM) in food (base feed, BF) acts as an additional attractant for Cherax quadricarinatus and, if so, the concentration required for optimal effectiveness. Incorporation of SM was evaluated through individual and group behavioral tests. The second objective was to analyze the effect of food availability on behavior and level of digestive enzyme activity after short-term (48 h) and long-term (16 d) starvation periods. To assess the effect of either starvation period, 3 different treatments were conducted: no feed (control), available BF, and BF present but not available. Individual and group behavior showed no differences among treatments with different percentages of SM inclusion in BF. The time spent in chambers with different percentages of SM was similar in all treatments. Levels of amylase activity and soluble protein, as a function of food availability after a short- or long-term starvation period, were not altered. Digestive enzyme activity was not affected after 2 d of starvation in response to the treatment. However, change was observed in enzymatic profiles after juveniles were deprived of food for 16 d. The main responses were given by lipase, protease and trypsin activity. Based on previous studies and the present results, we propose a hypothesis for a possible regulation of the digestive and intracellular lipase activities depending on food availability."

Article

Chemical stimuli, Crustaceans, Digestive enzyme, Food searching behavior, Food attractants, Starvation BIOLOGÍA Y QUÍMICA CIENCIAS DE LA VIDA BIOQUÍMICA ENZIMOLOGIA

Potencial enzimático de Pleurotus levis para biorremediar suelos agrícolas contaminados por hidrocarburos del petróleo en México

ZULMA BOLAÑOS GARCIA (2015)

Tesis (Maestría en Ciencias, especialista en Estrategias para el Desarrollo Agrícola Regional).- Colegio de Postgraduados, 2015.

Al ser México un país productor de petróleo presenta un gran problema de contaminación por hidrocarburos poliaromáticos (HAPs), esta situación perjudica algunas zonas agrícolas en México. Los HAPs son altamente tóxicos, mutagénicos y carcinogénicos. Una alternativa para solucionar este problema es la biorremediación utilizando hongos. Las especies del género Pleurotus presentan un sistema enzimático extracelular capaz de biodegradar y mineralizar compuestos xenobióticos, tales como los HAPs, entre ellos el antraceno. En la presente investigación se determinó el potencial enzimático de P. levis (CP-30) y de P. ostreatus (CP-754), como alternativa para biorremediar a futuro suelos agrícolas contaminados con HAPs. Se determinó la actividad enzimática de lacasas, manganeso peroxidasas (MnP) y lignino peroxidasas (LiP) en presencia de ácido acetil salicílico (AAS) y de antraceno. Se realizaron diseños experimentales completamente al azar, en donde se presentó un incremento en la actividad de lacasas y MnP al adicionar AAS. La mayor actividad de lacasas en presencia de AAS y 0.4 g de antraceno fue en P. levis (CP-30) con 42.005 U mL-1, y en P. ostreatus (CP-754) con 12.487 U mL-1; la mayor actividad de MnP se presentó en P. levis (CP-30) con 0.216 U L-1 y en P. ostreatus (CP-754) con 0.388 U L-1. P. levis (CP-30) presentó una mayor actividad de lacasas, mientras que P. ostreatus (CP-754) una actividad de MnP similar a P. levis (CP-30) en presencia de antraceno. Se presenta una estrategia para biorremediar suelos agrícolas contaminados con hidrocarburos empleando cepas nativas de P. levis. _______________ ENZYMATIC POTENTIAL OF Pleurotus levis FOR BIOREMEDIATE CONTAMINATED BY PETROLEUM HYDROCARBONS IN MEXICO AGRICULTURAL SOILS. ABSTRACT: As a oil producer Mexico presents a big problem of contamination by polyaromatic hydrocarbons (PAHs), this situation harms some agricultural areas in Mexico. PAHs are highly toxic, mutagenic and carcinogenic compounds. An alternative to solve this problem is bioremediation using fungi mushrooms. Pleurotus fungi exhibit an extracellular enzymatic system capable of biodegrading and mineralize xenobiotic compounds PAHs such as anthracene. In the present research project the enzymatic potential of P. levis (CP-30) and P. ostreatus (CP-754) as an alternative to bioremediate agricultural soils contaminated with PAHs were determined. The laccases, manganese peroxidases (MnP) and lignin peroxidases (LiP) activity in the presence of acetylsalicylic acid (ASA) and anthracene were analyzed. In a completely randomized experimental design, an increase in the laccase and MnP activity by adding AAS was observed. Greater laccase activity in the presence of ASA and 0.4 g of anthracene in P. levis (CP-30) 42.005 U mL-1, and P. ostreatus (CP-754) 12.487 U mL-1 was observed; the most MnP activity of in P. levis (CP-30) with 0.216 U L-1 and P. ostreatus (CP-754) with 0.388 U L-1 was produced. This paper P. levis (CP-30) had a higher laccase activity and P. ostreatus (CP-754) MnP activity like that P. levis (CP-30) in the presence of anthracene, this represents an alternative to remediate agricultural soils contaminated with hydrocarbons with native strains of P. levis.

Master thesis

Antraceno Biorremediación Biotecnología Enzimas Hongos comestibles Pleurotus Anthracene Bioremediation Biotechnology Edible mushrooms Enzymes Estrategias para el Desarrollo Agrícola Regional Maestría CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA

Activity profiling of barley vacuolar processing enzymes provides new insights into the plant and cyst nematode interaction

Abdelfattah DABABAT (2020)

Vacuolar processing enzymes (VPEs) play an important role during regular growth and development and defence responses. Despite substantial attempts to understand the molecular basis of plant–cyst nematode interaction, the mechanism of VPEs functioning during this interaction remains unknown. The second‐stage Heterodera filipjevi juvenile penetrates host roots and induces the formation of a permanent feeding site called a syncytium. To investigate whether infection with H. filipjevi alters plant host VPEs, the studies were performed in Hordeum vulgare roots and leaves on the day of inoculation and at 7, 14 and 21 days post‐inoculation (dpi). Implementing molecular, biochemical and microscopic methods we identified reasons for modulation of barley VPE activity during interaction with H. filipjevi. Heterodera filipjevi parasitism caused a general decrease of VPE activity in infected roots, but live imaging of VPEs showed that their activity is up‐regulated in syncytia at 7 and 14 dpi and down‐regulated at 21 dpi. These findings were accompanied by tissue‐specific VPE gene expression patterns. Expression of the barley cystatin HvCPI‐4 gene was stimulated in leaves but diminished in roots upon infestation. External application of cyclotides that can be produced naturally by VPEs elicits in pre‐parasitic juveniles vesiculation of their body, enhanced formation of granules, induction of exploratory behaviour (stylet thrusts and head movements), production of reactive oxygen species (ROS) and final death by methuosis. Taken together, down‐regulation of VPE activity through nematode effectors promotes the nematode invasion rates and leads to avoidance of the induction of the plant proteolytic response and death of the invading juveniles.

Article

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA HORDEUM VULGARE HETERODERA PLANT NEMATODES ENZYMES