ABSTRACT The fungal microbiota associated with the roots and rhizosphere of plants represents a significant source of biocontrol agents against the root-knot nematode Meloidogyne spp. While some fungal genera have been studied extensively, others require more attention in terms of their identity and mechanisms of action against plant parasitic nematodes. Thus, the aim of this research was to demonstrate the in vitro and in vivo biocontrol potential of fungi isolated from the root and rhizosphere of guava plants against the root-knot nematode Meloidogyne incognita. We isolated four fungi (C5, C6, C7, and C10) from the root and rhizosphere of guava plants using the serial dilution method. These fungi were purified on potato dextrose agar and evaluated in vitro to assess their ability to parasitize M. incognita eggs and juveniles. Subsequently, the fungi were assessed for M. incognita control under nursery conditions in guava plants. The identity of the fungi with parasitic capacity and biocontrol potential was confirmed by amplifying and sequencing the ITS region, followed by Bayesian inference analysis. Results showed that the fungi corresponded to Talaromyces sayulitensis (C5), Myrothecium sp. (C6), Penicillium shearii (C7), and Beauveria bassiana (C10). Parasitism of M. incognita eggs was confirmed for all fungi, parasitism of juveniles occurred with T. sayulitensis (C5) and B. bassiana (C10). In guava seedlings treated with fungal isolates, a significant reduction in the number of eggs, juveniles, and nodules per gram of root was achieved. The biocontrol potential against M. incognita in guava seedlings was confirmed for different fungi associated with the root rhizosphere. rootknot knot spp extensively nematodes Thus C5, C5 C (C5 C6 C7 C10 method M Subsequently region analysis , sp (C6) (C7) C10. . (C10) T B isolates achieved (C C1 (C6 (C7 (C10 (C1

Resumen Objetivo: Analizar los componentes subyacentes de las presiones inspiratorias (MIP) y espiratorias (MEP) es táticas máximas reducidas en sujetos con distrofia de Duchenne (DMD). Métodos: Se evaluaron 43 pacientes mediante pruebas de función pulmonar rutinarias. MIP y MEP fueron medidas a inspiración y espiración máximas. Los volúmenes pulmonares se midieron mediante dilución de helio. Resultados: Edad media 13 años (rango 7-20 años). La capacidad pulmonar total (TLC) y el volumen residual (RV) fueron 78.0% (49.0-94.0) y 27.0% (19.7- 30.1) de los valores predichos. El RV/TLC fue de 35.3% (28.1-47.7). Treinta y cinco sujetos tenían una TLC por debajo del límite inferior de normalidad, 31 tenían una RV/TLC por encima del límite superior de la normalidad. MIP y MEP fueron -53.0 (-65.5 a -41.8) y 58.0 (41.5-74.8) cmH2O, mientras que en % de los predichos (TLC y RV predichos) fueron 42.6 (33.3-50.8) y 33.7 (23.9-44.5). MIP en % del RV alcanzado (Grupo A 7-11 años) fue mayor (p 0.025), y MEP en % de la TLC alcanzada Grupo B (12-16 años) y C (17-20 años), también fue mayor (0.031). Conclusiones: En sujetos con DMD, debilidad intrínseca de los músculos respiratorios y desventaja mecánica conducen a generación de presión estática máxima inadecuada. Las mismas deben interpretarse con cautela, ya que sobrestiman la debilidad de los músculos respiratorios si se las compara con las tablas de valores predichos obtenidos a TLC y RV. Nuestros resultados proporcionan datos adicionales que respaldan la utilización de valores absolutos en lugar de los predichos.

Abstract Objective: To analyze the underlying components of reduced maximal static inspiratory (MIP) and expiratory (MEP) pressures in subjects with Duchenne muscular dystrophy. Methods: Forty-three subjects were assessed based on routine pulmonary function tests. MIP and MEP were measured the subjects performed maximal expirations and inspirations using a snorkel mouthpiece. Lung volumes were measured us ing the helium dilution technique. Results: The mean age was 13 years (range, 7-20 years). Median total lung capacity (TLC) and residual volume (RV) were 78.0 (49.0-94.0) and 27.0 (19.7-30.1) of the predicted values re spectively. The RV/TLC relationship was 35.3% (28.1-47.7). Thirty-five subjects had a TLC below the lower limit of normal, while 31 had an RV/TLC ratio above the upper limit of normal. The median (IQR) MIP and MEP values were -53.0 (-65.5 to -41.8) and 58.0 (41.5-74.8) cmH2O respectively. MIP and MEP in percent of the predicted values (predicted TLC and RV) were 42.6 (33.3-50.8) and 33.7 (23.9-44.5). MIP in percent of the RV reached for Group A (7-11 years old) was higher (p 0.025) while MEP in percent of the TLC reached for Group B (12-16 years) and C (17-20 years) were higher too (0.031). Conclusions: In subjects with Duchenne muscular dystrophy, the intrinsic weakness of respiratory muscles and mechanical disadvantage lead to inadequate maximal static pressure generation. Maximal static pressures should be interpreted cautiously as they overestimate respiratory muscle weakness when compared to predicted values obtained at TLC and RV. Our results provide additional data supporting absolute values use rather than predicted values.

Resumen: Los metales pesados en los suelos agrícolas son absorbidos y pueden ser acumulados por los cultivos, representando un riesgo potencial a la salud humana. La presente investigación tuvo como objetivo estudiar la concentración y transferencia de Cd, Cr, Cu, Pb y Zn en lechugas irrigadas con aguas tratadas cultivadas bajo diferentes prácticas agrícolas. Cuatro tratamientos fueron evaluados: 1.- riego rodado sin acolchar sin composta, 2.- riego con cintilla sin acolchar con composta, 3.- riego con cintilla con acolchado sin composta, 4.- riego con cintilla con acolchado con composta. Las concentraciones detectadas de Cd, Cr, Pb y Zn en parte comestible de lechugas rebasaron los niveles máximos permisibles en vegetales que establece la referencia de la Unión Europea. En el caso de Cd, mostró una alta capacidad de transferirse del suelo a la planta, lo que representa un riesgo a la salud aún mayor. Las prácticas agronómicas de riego con cintilla, utilizando agua proveniente de una planta de tratamiento de aguas residuales, acolchado plástico y abonado orgánico reducen discretamente la concentración e índice de transferencia de Cd, Cr, Cu, Pb y Zn en parte comestible de lechuga debido a que promueven un incremento en la producción de biomasa, lo que a su vez afecta la dilución de los metales pesados en los tejidos de las plantas.

Summary: Heavy metals can be found in agricultural soils, absorbed and accumulated by crops, representing a public health risk. This research aimed to study the influence of agricultural practices on the concentration of heavy metals cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) in lettuce irrigated with treated water and determined the level of risk to human health. Four treatments were evaluated: (1) Flood irrigation without mulch and compost; (2) Drip irrigation without mulching with compost; (3) Drip irrigation with mulch without compost; (4) Drip irrigation with mulch and compost. The detected concentrations of Cd, Cr, Pb and Zn in the edible part of lettuce exceeded the maximum permissible levels in vegetables established by the European Union reference. In the case of Cd, it showed a high capacity to be transferred from the soil to the plant, which represents an even greater health risk. The agronomic practices of drip irrigation, using water from a wastewater treatment plant, plastic mulch and organic fertilizer slightly reduce the concentration and transfer rate of Cd, Cr, Cu, Pb and Zn in the edible part of lettuce, promoting an increase in biomass production, which in turn affects the dilution of heavy metals in plant tissues.

Resumen: Psittacanthus calyculatus es una planta hemiparásita que afecta diversas especies vegetales de gran importancia para el ecosistema. Existen diversos reportes sobre su capacidad antibacteriana debido a que contiene diversos compuestos con actividad antioxidante y antimicrobiana, sin embargo, sobre su actividad antifúngica es prácticamente nula la información disponible. Por lo que el objetivo del presente trabajo fue conocer la actividad antifúngica de extractos de muérdago ante la inhibición de Colletotrichum. gloeosporioides, Fusarium sp. y Curvularia sp. Para ello, se utilizó hoja y flor de muérdago obtenidos de dos hospederos: Prosopis laevigata y Eysenhardtia polystachya. Las muestras se lavaron, deshidrataron y molieron. Posteriormente se realizó una extracción sólido-líquido utilizando el metanol-acetona-agua. Se cuantificó el contenido de fenoles y flavonoides, además el perfil fitoquímico cualitativo. La evaluación de la actividad antifúngica se llevó a cabo con la técnica de dilución en placa con medio PDA. Se determinaron los parámetros de inhibición del crecimiento micelial, esporulación, germinación y se determinó el efecto fungicida o fungistático. Los resultados muestran inhibición mayor al 70% con extractos de hoja y flor, siendo Curvularia sp. el más susceptible con un 98% de inhibición. También hubo reducción de la esporulación y germinación de los fitopatógenos evaluados. Se determinó que la inhibición corresponde a un efecto fungistático. Los resultados revelan alta capacidad de inhibición in vitro de extractos de muérdago contra fitopatógenos de gran importancia para la agricultura.

Abstract: Psittacanthus calyculatus is a hemiparasitic plant that affects various plant species of great importance to the ecosystem. Contains various compounds with antioxidant and antimicrobial activity. There are various reports on its antibacterial capacity; however, there is no information available on its antifungal activity. That is why the aim of this work was to show the antifungal activity of mistletoe extracts against the inhibition of Colletotrichum gloeosporioides, Fusarium sp. and Curvularia sp. For this, both mistletoe leaves and flowers obtained from two hosts were used: Prosopis laevigata and Eysenhardtia polystachya. The samples were washed, dehydrated and ground. Subsequently, a solid-liquid extraction was carried out using methanol-acetone-water. The content of phenols and flavonoids was quantified, as well as the phytochemical profile qualitatively. The evaluation of the antifungal activity was carried out with the plate dilution technique with PDA medium. The parameters of inhibition of mycelial growth, sporulation, germination was evaluated and the fungicidal or fungistatic effect was determined. The results showed an inhibition greater than 70% using both leaf and flower extracts, with Curvularia sp. being the most susceptible with 98% inhibition. There was also a reduction in sporulation and germination of the evaluated phytopathogens. It was determined that the inhibition corresponds to a fungistatic effect. The results reveal a high in vitro inhibition capacity of mistletoe extracts against phytopathogens of great importance for agriculture.

Resumen: El esquema actual de fertilización con nitrógeno (N) para el trigo de primavera se desarrolló bajo una rotación dominante de cultivo-pastura. Después de 2002, este sistema se convirtió en un sistema de cultivo anual continuo con labranza cero, reduciendo progresivamente la capacidad de suministro de N del suelo. Además, el mayor rendimiento en grano de las nuevas variedades aumentó la demanda de N. El fertilizante nitrogenado adicional requerido se puede ajustar monitoreando el estado nutricional del cultivo. Nuestros objetivos fueron: i) determinar el estado óptimo de N en diferentes etapas fenológicas; ii) cuantificar la brecha de rendimiento del trigo explicada por el déficit de suministro de N, y iii) evaluar el valor crítico del índice de nutrición nitrogenada (INN) como predictor de respuesta al agregado de fertilizante nitrogenado en GS 3.3. Ajustamos la curva de dilución de nitrógeno (Nc=4,17MS-0,31), derivando un INN crítico en GS 3.3 (INN=1,24). Según la capacidad de suministro de N del suelo y el INN en GS 3.3, la brecha de rendimiento del trigo atribuida al déficit de suministro de N varió de 0 a 2,74 Mg ha-1, con un promedio de 0,76 Mg ha-1. El INN crítico propuesto en GS 3.3 fue efectivo para diagnosticar la demanda de N del cultivo y lograr el rendimiento alcanzable en diferentes escenarios.

Abstract: Current nitrogen (N) fertilization schedule for spring wheat was developed under a dominant crop-pasture rotation. After the year 2002, this cropping system was converted to continuous annual cropping systems under no-till, reducing soil N supply capacity progressively. Additionally, highest grain yield of new varieties increased N demand. The required additional N fertilizer can be adjusted by monitoring nutritional status of the crop. Our objectives were: i) to determine optimal N status at different phenological stages; ii) to quantify the wheat yield gap explained by N supply deficit, and iii) to assess the critical nitrogen nutrition index (NNI) value as a predictor of response to N fertilizer applied at GS 3.3. We adjusted the nitrogen dilution curve (Nc=4.17DM-0.31), deriving a critical NNI at GS 3.3 (NNI=1.24). Depending on soil N supply capacity and NNI at GS 3.3, wheat yield gap attributed to N supply deficit varied from 0 to 2.74 Mg ha-1, averaging 0.76 Mg ha-1. The critical NNI proposed at GS 3.3 was effective to diagnose the N crop demand to reach the attainable yield under different scenarios.

Resumo: O esquema atual de fertilização com nitrogênio (N) para o trigo de primavera foi desenvolvido sob uma rotação dominante de cultivo e pastagem. A partir de 2002, esse sistema passou a ser um sistema de cultivo anual contínuo com plantio direto, reduzindo progressivamente a capacidade de suprimento de N do solo. Além disso, o maior rendimento de grãos das novas variedades aumentou a demanda por N. O fertilizante de nitrogênio adicional necessário pode ser ajustado monitorando o estado nutricional da cultura. Nossos objetivos foram: i) determinar o estado ótimo do N em diferentes estágios fonológicos; ii) quantificar a lacuna de produtividade do trigo explicada pelo déficit de oferta de N e iii) avaliar o valor crítico do índice de nutrição de nitrogênio (INN) como preditor de resposta à adição de fertilizante nitrogenado no GS 3.3. Ajustamos a curva de diluição de nitrogênio (Nc=4,17MS-0,31), derivando um INN crítico em GS 3,3 (INN=1,24). De acordo com a capacidade de suprimento de N do solo e do INN no GS 3.3, a diferença de produtividade do trigo atribuída ao déficit de suprimento de N variou de 0 a 2,74 Mg ha-1, com média de 0,76 Mg ha-1. O INN crítico proposto em GS 3.3 foi eficaz para diagnosticar a demanda de N da cultura para atingir o rendimento alcançável em diferentes cenários.

RESUMEN El objetivo del estudio fue evaluar el caseinato de sodio (CS) en la dilución y la congelación de semen bovino. Quince eyaculados provenientes de cinco toros fueron diluidos y congelados individualmente con un diluyente compuesto por tris-glicerol- ácido cítrico con 8% v/v de lipoproteínas de baja densidad (LDL) y suplementado con CS en cuatro tratamientos: CS 3% p/v (CS3), CS 4% p/v (CS4), CS 5% p/v (CS5) y sin CS (Control). Se evaluaron la movilidad y cinética (Sistema SCA®) y la integridad funcional de membrana (prueba HOS) del semen fresco, diluido y descongelado. Además, se evaluó la morfología y vitalidad (eosina-nigrosina) del semen fresco y diluido, y la integridad estructural de membrana (SYBR14/IP), la integridad acrosómica (FITC-PNA) y la capacidad fertilizante in vitro (FIV) del semen descongelado. El análisis estadístico de los parámetros de calidad espermática se realizó mediante modelos mixtos y la compa- ración de las medias por la prueba de Tukey. El análisis estadístico de la FIV se realizó con la prueba de Kruskal-Wallis. CS3 produjo un incremento de la movilidad progresiva y la frecuencia de batido del semen descongelado (p<0.05). CS4 tuvo un efecto deletéreo sobre la movilidad progresiva del semen diluido, mientras CS4 y CS5 afectaron la movilidad, cinética e integridad de membrana del semen descongelado (p<0.05). No se encontraron diferencias para la FIV (p>0.05). La suplementación del diluyente de congelación con caseinato de sodio puede mejorar la calidad posdescongelación del semen bovino.

ABSTRACT The aim of this study was to evaluate sodium caseinate (CS) in the dilution and freezing of bovine semen. Fifteen ejaculates from five bulls were diluted and then individually frozen using an extender composed of tris-glycerol-citric acid with 8% v/v of low-density lipoproteins (LDL) and supplemented with CS in four treatments: CS 3% w/ v (CS3), CS 4% w/v (CS4), CS 5% w/v (CS5) and without CS (Control). The motility and kinetics (SCA® System) and the functional integrity of the membrane (HOS test) of the fresh, extended and thawed semen were evaluated. In addition, the morphology and vitality (eosin-nigrosin) of the fresh and extended semen, and the structural integrity of the membrane (SYBR14/IP), the acrosome integrity (FITC-PNA) and the in vitro fertilizing capacity (IVF) of thawed semen were evaluated. The statistical analysis of the sperm quality parameters was performed using mixed models and the comparison of the means by the Tukey test. Statistical analysis of IVF was performed with the Kruskal-Wallis test. CS3 produced an increase in progressive motility and beat cross frequency of thawed semen (p<0.05). CS4 had a deleterious effect on progressive motility of extended semen, while CS4 and CS5 affected the motility, kinetics and membrane integrity of thawed semen (p<0.05). No differences were found for IVF (p>0.05). Supplementation of freezing extender with sodium caseinate can improve post-thaw quality of bovine semen.

ABSTRACT The reproductive activity of various species of mammals is influenced by the sperm subpopulations of their ejaculates. These subpopulations differ in the motility and kinetic characteristics of the sperm and have been related and classified according to their capacity for the fertilization process. The objective of this research was to evaluate the effect of the composition of the semen diluent on the sperm subpopulations of the chilled rabbit semen. The semen of 10 rabbits of the Californian breed (three ejaculated per animal) was obtained. Each ejaculate was divided into four aliquots, which were diluted in one of four diluents, whose basic composition consisted of T1: skim milk and sugars; T2: dextrose, sodium citrate and potassium acetate; T3: sodium caseinates, phosphates and sugars; and T4: tris-citric acid and egg yolk. Each aliquot was kept refrigerated at 16 °C for 72 h. Immediately after dilution and every 24 h, the distribution of four sperm subpopulations was evaluated using a computerized system: Type A (rapid progressive spermatozoa), Type B (rapid spermatozoa and medium progressive spermatozoa), Type C (medium spermatozoa and slow spermatozoa) and Type D (static spermatozoa). The data were analyzed using the PROC GLM and Tukey’s HSD test of the SAS v. 9.2. It was found that T1 and T3 produced superior results for curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP) and amplitude of lateral head displacement (ALH) of sperm refrigerated for 24 and 48 hours (p<0.05), while T2 and T4 produced an increase in the beat cross frequency (BCF) (p<0.05). It is concluded that the composition of the diluent influences the distribution of the sperm subpopulations of the refrigerated rabbit semen, by generating changes in the progressivity and kinetics of the sperm.

RESUMEN La actividad reproductiva de diversas especies de mamíferos se encuentra influenciada por las subpoblaciones espermáticas de sus eyaculados. Dichas subpoblaciones se diferencian en las características de movilidad y cinética de los espermatozoides y han sido relacionadas y catalogadas según su capacidad para el proceso de fertilización. El objetivo de este estudio fue evaluar el efecto de la composición del diluyente de semen sobre las subpoblaciones espermáticas del semen refrigerado de conejo. Se obtuvo el semen de 10 conejos de la raza Californiano (tres eyaculados por animal). Cada eyaculado se dividió en cuatro alícuotas, las cuales se diluyeron en uno de cuatro diluyentes, cuya composición básica consistió en T1: leche descremada y azucares; T2: dextrosa, citrato sódico y acetato potásico; T3: caseinatos de sodio, fosfatos y azúcares; y T4: tris-ácido cítrico y yema de huevo. Cada alícuota se mantuvo en refrigeración a 16 °C durante 72 horas. Inmediatamente después de la dilución y cada 24 horas se evaluó la distribución de cuatro subpoblaciones de espermatozoides mediante un sistema computarizado: Tipo A (espermatozoides rápidos progresivos), Tipo B (espermatozoides rápidos y espermatozoides medios progresivos), Tipo C (espermatozoides medios y espermatozoides lentos), y Tipo D (espermatozoides estáticos). Los datos se analizaron mediante el PROC GLM y la prueba HSD de Tukey del software SAS v. 9.2. Se encontró que T1 y T3 produjeron resultados superiores para la velocidad curvilínea (VCL), la velocidad rectilínea (VSL), la velocidad promedio (VAP) y la amplitud de desplazamiento lateral de la cabeza (ALH) de los espermatozoides refrigerados durante 24 y 48 horas (p<0.05), mientras que T2 y T4 produjeron un incremento en la frecuencia de batido (BCF) (p<0.05). Se concluye que la composición del diluyente influye sobre la distribución de las subpoblaciones espermáticas del semen refrigerado de conejo, al generar cambios en la progresividad y la cinética de los espermatozoides.

Buffers are a widely used resource to keep solutions from abruptly change their pH when amounts of acids or bases are added or when dilution occurs. Considering this, buffer is a topic addressed in several university majors and due its relevance should be well known by students and by all professionals who eventually need to prepared a buffer. Mistakes during the procedure might bring unwanted effects depending on the purpose of the buffer. Even though the theory behind buffers is extensively covered in textbooks, the calculations required can sometimes be interpreted as difficult. Therefore, the aim of this work is to disseminate a tool to assist on these calculations. We provide a practical guide on how to prepare buffers of the user’s choice with or without ionic strength adjustment. Exploring the free software PeakMaster®, the user can calculate pH, ionic strength, buffer capacity and predict the precise concentration of each component involved to the proper preparation of the most common and several others buffer solutions. In addition, we hope this paper can be helpful for anyone who is interested in acquire deeper knowledge about buffers.

RESUMEN Se evaluó la capacidad de algas Chlorophyta aisladas de la laguna Limoncocha para remover materia orgánica en aguas residuales del Camal Municipal del cantón Shushufindi, Provincia de Sucumbíos - Ecuador. Se utilizó un fotobiorreactor tubular para aplicar seis tratamientos de 1.8 L, con cinco repeticiones cada uno. Los tratamientos dirigidos a evaluar el crecimiento de las algas consistieron en el uso del medio de cultivo Nitrofoska Foliar, con y sin aireación; para las pruebas de reducción de materia orgánica se aplicaron cuatro tratamientos con dilución de 1:3 del agua residual: dos unidades experimentales inoculadas con algas Chlorophyta, con y sin aireación; y dos unidades experimentales sin inoculación de algas, con y sin aireación. El fotoperiodo fue de 12 horas a 22.38°C y un pH de 8.45. El tratamiento más eficiente para la remoción de DBO5 (83.1%), fosfatos (58.9%), nitrógeno total Kjeldahl (63.1%), corresponde al cultivo aireado de algas Chlorophyta en agua residual diluida, presentando además mayor productividad celular (41944 células/L/día) en comparación al crecimiento en el medio de cultivo. La remoción más eficiente de sulfatos (58.9%) se obtuvo mediante el cultivo de algas Chlorophyta en agua residual diluida sin aireación.

ABSTRACT In this study, the capacity of isolated Chlorophyta algae from Limoncocha lagoon to remove organic matter in wastewater from the Shushufindi municipal slaughterhouse (Province of Sucumbios - Ecuador) was evaluated. Six different treatments of 1.8 L, with five replicates each, were applied in a tubular photobioreactor. The treatments aimed at assessing algae growth consisted of using of Nitrofoska foliar culture medium, with and without aeration; while for the organic matter reduction tests, four treatments were applied at a 1:3 dilution of the litter wastewater: two experimental units inoculated with Chlorophyta algae, one with aeration and one without aeration; and two experimental units without algae inoculation, with and without aeration. The photoperiod was 12 hours at 22.38°C and a pH value of 8.45. The most efficient treatment for the BOD5 (83.1%), phosphate (58.9%), and total Kjeldahl nitrogen (63.1%) removal was the aerated cultivation of Chlorophyta algae in diluted bed wastewater, showing higher cell productivity (41944 cells/L/day) compared to the growth in the culture medium. The most efficient sulfate removal (58.9%) was obtained by Chlorophyta algae culture in diluted, non-aerated, farmyard wastewater.

El presente trabajo cuyo objetivo fue evaluar la actividad antibacteriana in vitro del extracto etanólico de hojas de Origanum vulgare frente a Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 27853 y Escherichia coli ATCC 25922. El estudio fue experimental, se emplearon 72 unidades experimentales, constituidas por un tipo de extracto etanólico tres concentraciones, tres especies bacterianas y 8 repeticiones por grupo experimental. A través del método de dilución doble seriada se determinaron las diferentes concentraciones, para la actividad antibacteriana se empleó el método de difusión en pozo. Se emplearon concentraciones de 80, 40 y 20 mg/mL. El extracto etanólico presentó actividad antibacteriana in vitro, con un promedio del tamaño los halos de inhibición para S. aureus de 21.64, 15.24 y 11.45 mm, P. aeruginosa 13.31, 12.27 y 7.35 mm, E. coli de 12.5, 11.40 y 10.6 mm para las diferentes concentraciones. Se concluye que el extracto etanólico de O. vulgare tienen capacidad antibacteriana sobre S. aureus ATCC 29213, P. aeruginosa ATCC 27853 y E. coli ATCC 25922.

The present work whose objective was to evaluate the in vitro antibacterial activity of the ethanolic extract of Origanum vulgare leaves against Staphylococcus aureus ATCC 29213, Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922. The study was experimental, 72 experimental units were used, consisting of a type of ethanolic extract three concentrations, three bacterial species and eight repetitions per experimental group. Through the serial double dilution method, the different concentrations were determined, for the antibacterial activity, the well diffusion method was used. Concentrations of 80 mg/mL, 40 mg/mL and 20 mg/mL were used. The ethanolic extract showed antibacterial activity in vitro, with an average size of the inhibition halos for S. aureus of 21.64, 15.24 and 11.45 mm, P. aeruginosa 13.31, 12.27 and 7.35 mm, E. coli 12.5, 11.40 and 10.6 mm for the different concentrations. It is concluded that the ethanolic extract of O. vulgare has antibacterial capacity on S. aureus ATCC 29213, P. aeruginosa ATCC 27853 and E. coli ATCC 25922.

SUMMARY Orchids (family Orchidaceae) are susceptible to several biotic and abiotic factors that affect their development and quality. Among them, Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV) are the most frequent pathogens, with the greatest economic impact worldwide. The mechanical transmission of these viruses in addition to the predominantly agamic multiplication of orchids, make it necessary to work with virus-free plant material. The objective of this work was to develop diagnostic reagents for the detection of CymMV and ORSV. A polyclonal antiserum against CymMV + ORSV was made with a titer of 1:10000 determined by NC-ELISA. The antiserum was processed generating IgG and IgG-conjugated” anti CymMV+ORSV were obtained for use in DAS-ELISA in a dilution of 1:500. The immunodiagnostic capacity of this technique was evaluated by analyzing samples from orchids with characteristic viral symptoms, collected from commercial nurseries in the city of Córdoba, Argentina. Viral infections were detected in 22 % of the samples analyzed and in 75 % of the nurseries surveyed. The ability of these reagents to identify CymMV, ORSV and mixed infections in orchids, will speed up analyzes and reduce their costs. This would represent an advantage for large-scale detections.

RESUMEN Las orquídeas (familia Orchidaceae) son susceptibles a diversos factores bióticos y abióticos que afectan su desarrollo y calidad. Entre ellos, Cymbidium mosaic virus (CymMV) y Odontoglossum ringspot virus (ORSV) son los patógenos más frecuentes y de mayor importancia económica a nivel mundial. La transmisión mecánica de estos virus y la multiplicación principalmente agámica de las orquídeas hacen necesario contar con material madre libre de virus. El objetivo de este trabajo fue elaborar reactivos de diagnóstico para la detección de CymMV y ORSV. Se elaboró un antisuero policlonal contra CymMV+ORSV que se tituló 1:10000 mediante NC-ELISA. El antisuero fue procesado y se obtuvieron IgG e IgG-conjugada anti CymMV+ORSV dilución 1:500 para su utilización en DAS-ELISA. La capacidad inmunodiagnóstica de esta técnica se evaluó mediante el análisis de muestras provenientes de orquídeas con síntomas característicos de infección viral, recolectadas en viveros comerciales de la ciudad de Córdoba, Argentina. La presencia de virosis se detectó en el 22 % de las muestras estudiadas y en el 75 % de los establecimientos relevados. La capacidad de estos reactivos para identificar CymMV, ORSV e infecciones mixtas en orquídeas permitirá agilizar y economizar los análisis. Esto representaría una ventaja para las detecciones a gran escala.

ABSTRACT The diamonds production has a great impact on the economy of the Republic of Angola, in which Catoca plant is of particular relevance. The autogenous grinding plays an important role in the technology of processing kimberlitic ores, as it has the purpose of achieving the release at the coarsest possible sizes. In order to evaluate the influence of the rotation speed and the pulp density on the energy efficiency indicators of the mill, a series of tests was designed considering three speed levels (55, 65 and 80 % of the critical speed) and two levels of dilution (dilute pulps, 45-50 % solids, and dense pulps 55-60 % solid). A sampling system was organized in the industrial facility that allowed evaluating the size distribution of the particles in the mill discharge and the power consumed by its motor and its capacity were recorded. At the same time, the specific energy consumed by the mill was evaluated. The results show that both operational factors have a decisive influence on the indicators studied. The higher the density of the pulp and the rotational speed of the mill, the larger the size of the mill outlet. The speed of rotation strongly influences the energy consumption of the installation.

RESUMEN La producción de diamantes tiene gran impacto en la economía de la República de Angola, en la que tiene especial relevancia la planta de Catoca, en la cual la molienda autógena juega un papel relevante en la tecnología del procesamiento de las menas kimberlíticas, pues tiene la finalidad de conseguir la liberación a tamaños lo más gruesos posible. Con el objetivo de evaluar la influencia de la velocidad de giro y la densidad de la pulpa en los indicadores de eficiencia energética del molino, se diseñó una serie de ensayos considerando tres niveles de velocidad (55 %, 65 % y 80 % de la velocidad crítica) y dos niveles de dilución: pulpas diluidas (45 %-50 % de sólidos), y pulpas densas (55 %-60 % de sólido). Se organizó un sistema de muestreo en la instalación industrial que permitiera evaluar la distribución de tamaño de las partículas en la descarga del molino y se registraron la potencia consumida por su motor y su capacidad. Al mismo tiempo fue evaluada la energía específica consumida por el molino. Los resultados muestran que ambos factores operacionales influyen de manera decisiva en los indicadores estudiados. Mientras mayor es la densidad de la pulpa y la velocidad de giro del molino, mayor es el tamaño de la salida del molino. La velocidad de giro influye fuertemente en el consumo energético de la instalación.

RESUMO. Na soja uma parcela significativa do nitrogênio (N) requerido deriva de sua simbiose com a bactéria do gênero rhizóbio. No entanto, informações sobre variabilidade genética disponível para a capacidade de fixação de N2 em diferentes estádios fenológicos é limitada. O objetivo deste estudo foi investigar a capacidade de fixação de N2 durante a fase inicial e final de desenvolvimento de 22 genótipos de soja comparada a de genótipos não nodulantes e supernodulante utilizados como testemunhas, e também identificar os caracteres mais informativos para fins de seleção. Dois ciclos de experimentos foram conduzidos em casa de vegetação para estimar o percentual de N derivado da atmosfera (%Ndda), assim como outros 10 caracteres relacionados a fixação de N2. Os resultados demonstraram que o %Ndda foi significativamente diferente entre os genótipos nas duas avaliações. Leituras de fotossíntese com SPAD apresentaram a maior correlação com a avaliação inicial de fixação de N2, enquanto que a massa seca da parte aérea demonstrou a mais alta correlação com a avaliação de fixação de N2 na fase final de desenvolvimento. Avaliações do %Ndda nas fases inicial e final de desenvolvimento da cultura podem ser utilizadas para seleção de genótipos superiores de soja para fixação de N2, assim como para o estudo dos mecanismos de controle nos âmbitos fisiológico e molecular.

ABSTRACT. Soybean derives a significant portion of the required nitrogen (N) from the symbiosis with rhizobia bacteria. However, information on the available genetic variation for N2 fixation capacity in different growth stages of soybean is limited. The objective of this study was to investigate the N2 fixation capacity of 22 soybean lines compared with that of non-nodulating and supernodulating checks at the early and late growth stages and identify the most informative traits for selection. Two cycles of greenhouse experiments were carried out to estimate the percentage of N derived from the atmosphere (%Ndfa) as well as 10 different traits related to N2 fixation. The results showed that %Ndfa was significantly different among the lines at the early and late growth stages. SPAD readings showed the highest correlation with the early N2 fixation, whereas shoot dry weight with the late N2 fixation. Early and late %Ndfa could be used to select superior lines for N2 fixation and study the underlying physiological and molecular mechanism.

RESUMO Neste trabalho objetivou-se verificar a capacidade de retardância de chamas de dois produtos comerciais aplicados em quatro espécies florestais (Eucalyptus saligna, Eucalyptus dunnii, Corymbia maculata e Eucalyptus grandis) avaliando a sua perda de massa ao longo do processo de combustão e o comportamento das amostras quando submetidas a elevadas temperaturas. Neste, foram utilizadas 9 amostras de cada espécie. Para a caracterização física das espécies (massa aparente (g/cm3) e porosidade (%)), foram preparados 15 amostras de cada, totalizando 96 corpos de prova escolhidos aleatoriamente (2,5 x 2,5 x 2,5cm). Todos foram estabilizados a 12% de umidade em câmara climatizada. Após, com o auxílio de um pincel, foram aplicadas três camadas dos produtos aqui testados sobre as amostras, e estas foram aplicadas em intervalos de 24 horas. A diluição dos produtos obedeceu às recomendações de seus fabricantes. Para o processo de combustão das amostras, utilizou-se um bico de Bunsen, onde as amostras foram submetidas a chama oxidante deste até ocorrer a perda de 80% de sua massa ao longo do tempo. Durante o processo de combustão, a cada 30 segundos, verificou-se a perda de massa que ocorreu na amostra neste intervalo de tempo. Assim, foi possível obter curvas que permitiram analisar e caracterizar a resistência térmica da madeira com base na perda de massa das diferentes espécies aqui estudadas. Ambos os produtos se mostraram eficazes no que diz respeito a capacidade retardante de perda de massa das amostras quando em elevadas temperaturas, mas o produto a base de nitrogenados e boratos se mostra mais eficiente em relação ao produto a base de resina sintética pigmentada com aditivos ignífugos (tinta ignífuga). Com relação à eficácia destes sobre as madeiras, os resultados variam de acordo com a espécie estudada e isso, possivelmente, devido a composição química de cada variedade.

ABSTRACT: The objective of this work was to verify the flame retardancy capacity of two commercial products applied in four forest species (Eucalyptus saligna, Eucalyptus dunnii, Corymbia maculata and Eucalyptus grandis) evaluating their loss of mass throughout the combustion process and the behavior of the when subjected to high temperatures. In this, 9 samples of each species were used. For the physical characterization of the species (apparent mass (g/cm3) and porosity (%)), 15 samples of each were prepared, totalizing 96 randomly selected test pieces (2.5 x 2.5 x 2.5cm). All were stabilized at 12% humidity in a heated room. Then, with the aid of a brush, three layers of the products tested on the samples were applied, and these were applied at 24 hour intervals. The dilution of the products obeyed the recommendations of their manufacturers. For the combustion of the samples, a Bunsen nozzle was used, where the samples were subjected to the flame of oxidation until the loss of 80% of its mass over time. During the combustion process, every 30 seconds, the mass loss occurred in the sample in this time interval. Thus, it was possible to obtain curves that allowed to analyze and to characterize the thermal resistance of the wood based on the loss of mass of the different species studied here. Both products proved to be effective as regards the retarding ability of mass loss of samples when at high temperatures, but the product based on nitrogen and borates is more efficient compared to the product based on synthetic resin pigmented with flame retardant additives (flame retardant paint). Regarding the effectiveness of these on the woods, the results vary according to the species studied and this possibly due to the chemical composition of each variety.

Resumen El suelo es la matriz fundamental donde suceden las reacciones químicas y biológicas que permiten el desarrollo de la vida en la tierra, y donde ocurren procesos fundamentales como la mineralización de los elementos y la fijación del nitrógeno. Hoy en día el nitrógeno se ha transformado en uno de los principales elementos contaminantes de los cuerpos de agua, causando consecuencias como la eutrofización de ríos, lago y costas. En los ambientes acuáticos, el nitrógeno puede ser encontrado en forma de amonio N-NH4 +, nitritos N-NO2 -o nitratos N-NO3 -, los cuales pueden ser utilizados por las bacterias nitrificantes amonio y nitrito oxidantes y desnitrificantes para su crecimiento y consecuente remoción. Esta investigación se planteó como objetivo evaluar la capacidad nitrificante de diferentes aislamientos bacterianos autóctonos, aislados de suelos cercanos a fuentes de vertido de aguas residuales de tipo doméstico para su potencial uso en sistemas de tratamiento de aguas residuales. Se realizó el recuento de bacterias nitrificantes por la técnica de dilución seriada y siembra en placas de agar mínimo mineral, su aislamiento por repique en placa hasta obtener colonias axénicas, su identificación por medio de baterías bioquímicas o secuenciación genética y la cuantificación de su capacidad nitrificante por los métodos 4500- NH4 +-F y 4500- NO- 2-B, entre el 26/09/2011 y 16/03/2014; las bacterias fueron aisladas de un punto del río Pirro contaminado con nitrógeno de aguas residuales de tipo doméstico. Se lograron aislar y purificar siete cepas de microorganismos nitrificantes entre las que se encuentran cuatro de Streptomyces sp., una de Pseudomonas putida, una de Sphingomonas sp. y una de Aeromonas sp. Se encontró que existen 2.23 x105 UFC/g de suelo de bacterias amonio oxidantes y 2.2 x104 UFC/g de suelo de las nitrito oxidantes. La cuantificación de la capacidad nitrificante de las cepas por medio de los métodos colorimétricos determinó que la capacidad máxima de remoción de amonio es de 0.050 mg N/L/día y la de nitrito en 0.903 mg N/L/día. La obtención de pocas cepas de organismos nitrificantes y un bajo recuento de UFC se puede atribuir a la técnica empleada, ya que esta solo recupera un 1 % de los microorganismos presentes en una muestras, lo cual sin embargo, es aceptable para estudios que tienen como objetivo la obtención de microorganismos cultivables. Se recomienda realizar ensayos de remoción con niveles de amonio y nitrito más altos para hallar la capacidad máxima de los microorganismos aislados.

Abstract Currently, nitrogen has become the main element of water pollution, causing riverine, lacustrine and coastal eutrophication. The continuous contamination of aquifers and the absence of planned water resource utilization, boost its scarcity, and has been the only way in which our societies become aware of the urgent need to process the generated wastewater. The objective of this research was to evaluate the nitrifying capacity of different autochthonous bacterial isolates from soils from nearby sources of domestic wastewater drainage. For this, bacteria were isolated from Pirro River, contaminated with nitrogen of domestic sewage. Nitrifying bacteria were counted by serial dilution and agar plates, and were isolated until obtaining axenic colonies. These were identified by biochemical batteries or genetic sequencing, and the quantification of their nitrifying capacity was obtained by the methods 4500- NH4 + -F and 4500-NO-2-B, all between September 26, 2011 and March 16, 2014. A total of seven strains of nitrifying microorganisms were isolated and purified, including four Streptomyces sp., one Pseudomonas putida, one Sphingomonas sp. and one Aeromonas sp. We found that there were 2.23 x 105 UFC/g of soil of ammonium oxidizing bacteria and 2.2 x 104 CFU/g of soil of nitrite oxidizing bacteria in the samples. The quantification of the nitrifying capacity of the strains by colorimetric methods, determined that the maximum ammonium removal capacity was 0.050 mg N/L/day and 0.903 mg N/L/day of nitrite. The collection of few strains of nitrifying organisms and a low CFU count, can be attributed to the technique used, since this only recovers 1 % of the microorganisms present in a sample, which, however, is acceptable for studies which main purpose is to obtain cultivable microorganisms. Future research should consider removal tests with higher ammonium and nitrite levels, to find the maximum capacity of the isolated microorganisms, and evaluate their potential use in wastewater treatment systems.