AGC. Ciencias Naturales

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Acceso abierto
A bioinspired peptide in tir protein as recognition molecule on electrochemical biosensors for the detection of e. Coli o157:H7 in an aqueous matrix
(Sulka, Grzegorz D., 2021-04-28) Ropero-Vega, Jose Luis; Redondo-Ortega, Joshua Felipe; Galvis-Curubo, Yuli Juliana; Rondon-Villarreal, Paola; Florez-Castillo, Johanna Marcela; Cibas
Currently, the detection of pathogens such as Escherichia coli through instrumental alternatives with fast response and excellent sensitivity and selectivity are being studied. Biosensors are systems consisting of nanomaterials and biomolecules that exhibit remarkable properties such as simplicity, portable, affordable, user‑friendly, and deliverable to end‑users. For this, in this work we report for the first time, to our knowledge, the bioinformatic design of a new peptide based on TIR protein, a receptor of Intimin membrane protein which is characteristic of E. coli. This peptide (named PEPTIR‑1.0) was used as recognition element in a biosensor based on AuNPs‑modified screen‑printed electrodes for the detection of E. coli. The morphological and electrochemical characteristics of the biosensor obtained were studied. Results show that the biosensor can detect the bacteria with limits of detection and quantification of 2 and 6 CFU/mL, respectively. Moreover, the selectivity of the system is statistically significant towards the detection of the pathogen in the presence of other microorganisms such as P. aeruginosa and S. aureus. This makes this new PEPTIR‑1.0 based biosensor can be used in the rapid, sensitive, and selective detection of E. coli in aqueous matrices.
Acceso abierto
Actinobacteria-enhanced plant growth, nutrient acquisition, and crop protection: Advances in soil, plant, and microbial multifactorial interactions
(2022-02-05) Mitra, Debasis; MondaL, Rittick; Khoshru, Bahman; Senapati, Ansuman; Radha, T. K.; Mahakur, Bhaswatimayee; Uniyal, Navendra; Myo, Ei Mon; Boutaj, Hanane; Guerra-Sierra, Beatriz Elena; Panneerselvam, Periyasamy; Ganeshamurthy, Arakalagud Nanjundaiah; Andelković, Snežana; Vasić, Tanja; Rani, Anju; Dutta, Subhadeep; Das Mohapatra, Pradeep K.; Microbiota
Agricultural areas of land are deteriorating every day owing to population increase, rapid urbanization, and industrialization. To feed today's huge populations, increased crop production is required from smaller areas, which warrants the continuous application of high doses of inorganic fertilizers to agricultural land. These cause damage to soil health and, therefore, nutrient imbalance conditions in arable soils. Under these conditions, the benefits of microbial inoculants (such as Actinobacteria) as replacements for harmful chemicals and promoting ecofriendly sustainable farming practices have been made clear through recent technological advances. There are multifunctional traits involved in the production of different types of bioactive compounds responsible for plant growth promotion, and the biocontrol of phytopathogens has reduced the use of chemical fertilizers and pesticides. There are some well-known groups of nitrogen-fixing Actinobacteria, such as Frankia, which undergo mutualism with plants and offer enhanced symbiotic trade-offs. In addition to nitrogen fixation, increasing availability of major plant nutrients in soil due to the solubilization of immobilized forms of phosphorus and potassium compounds, production of phytohormones, such as indole-3-acetic acid, indole-3-pyruvic acid, gibberellins, and cytokinins, improving organic matter decomposition by releasing cellulases, xylanase, glucanases, lipases, and proteases, and suppression of soil-borne pathogens by the production of siderophores, ammonia, hydrogen cyanide, and chitinase are important features of Actinobacteria useful for combating biotic and abiotic stresses in plants. The positive influence of Actinobacteria on soil fertility and plant health has motivated us to compile this review of important findings associated with sustaining plant productivity in the long run.
Acceso abierto
Actividad Acaricida In Vitro de Compuestos Sobre Schizotetranychus hindustanicus(Hirst), (Acari: Tetranychidae), Ácaro Hindú de los Cítricos
(2022-02-01) Ortiz-Meneses, Fredy Alejandro; Guerra-Sierra, Beatriz Elena; Osorio-Alvarado, Carlos Enrique; Rodriguez-Gonzalez, Leidy; Microbiota
El cultivo de lima Tahití(Citrus x latifolia Tanaka ex Q. Jiménez)ocupa un importante porcentaje dentro de la cadenacomercialde los cítricos en Colombia, pero es atacado por Schizotetranychus hindustanicus o ácarohindú, un fitófago que produce lesiones típicas en el haz de las hojas y frutos, caracterizadas por manchas blanquecinas circulares que corresponden a las telarañas que teje la hembra y que le restan valor estético al fruto y a su comercialización. El objetivo del presente estudio consistió en evaluar in vitrolos efectos acaricidas de distintos compuestos en tres tiempos de contacto sobre poblaciones del ácaro.Se evaluó extracto oleaginoso de Neem (Azadirachta indica)al 1,0%, azufre micronizado al 0,5%, extracto acuoso de Azadirachtina 0,4%, filtrado de caldo de ceniza al 15 %. Como control positivo se utilizó Abamectina al 0,2%, producto reconocido por su efecto acaricida, y se usó agua destilada como control negativo. Se evidenció que los tratamientos más efectivos fueronelextracto oleaginoso de Neem-A. indicaal1,0%, azufre micronizado al 0,5%, y Abamectina al 0,2% con valores de mortalidad del 96,4;97,9 y100 % a las 72 horasrespectivamente. Los resultados permiten sugerir el uso de compuestos naturales a base de Azadirachta indicaen soluciones oleaginosas para el control deesta plaga, pues no afectan el ecosistema a la vez que no se han reportado resistencias del fitófago por su uso.
Acceso abierto
Administración por valores : Estrategia de mejoramiento del clima organizacional en las empresas
(2018-04) Gómez Santos, Mónica Patricia; Vidal Tovar, Carlos Ramón; Ureña Villamizar, Yan Carlos; Acevedo Peñaloza, Carlos
Se presentan a continuación los resultados de la investigación sobre la Administración por Valores como estrategia de mejoramiento del clima organizacional empresarial en organizaciones localizadas en la ciudad de Valledupar, cuyo objetivo general fue establecer un programa de Administración por Valores como estrategia de mejoramiento del clima organizacional empresarial para lo cual se identificó la situación actual del clima organizacional que presenta la empresa; se determinó los valores que harán parte del programa de Administración por Valores y diseñan estrategias para la implementación de un programa de Administración por Valores. Para lo anterior se desarrolló un diagnóstico de la situación actual del clima organizacional; se establecen las debilidades, fortalezas, amenazas y oportunidades para el diseño e implementación del programa de Administración por Valores. De acuerdo a lo anterior, Existe la necesidad de formar y crear estrategias de compensación, distintas a las económicas, dentro de las empresas, y que se convierten en elementos motivadores y potenciadores de buen clima organizacional; la implementación del programa Administración por valores, permite generar una mejor actitud de parte de todo el personal de las empresas, desde los administrativos, operarios y comerciales, hacia el trabajo y el relacionamiento entre ellos. Además, en las organizaciones se ha generado una cultura de liderazgo y trabajo en equipo mucho más dinámica y espontánea, permitiendo el empoderamiento y la pertenencia hacia la organización.
Acceso abierto
Alteraciones anatómicas e histoquímicas ocasionadas por la oidiosis en hojas de Hydrangea macrophylla (Hydrangeaceae)
(2020-07-03) Rincón-Barón, Edgar Javier; Grisales-Echeverri, Claudia; Cuaran, Viviana Lucia; Cardona-B., Nadya Lorena; Microbiota
Anatomical and histochemical alterations caused by powdery mildew on Hydrangea mac-rophylla (Hydrangeaceae) leaves. Introduction: There are few studies concerning the morpho-anatomical and histochemical alterations caused by powdery mildew in H. macrophylla leaves in the scientific literature. Objective: To describe and analyze anatomical and histochemical aspects of this pathosystem. Methods: More than 90 leaves of H. macrophylla (both healthy and infected leaves by powdery mildew) were collected in the nursery El Jardín del Eden, Rionegro, Antioquia, Colombia. To carry out the identification of the mycopatho-gen, sections were stained with Lactophenol Blue, and contrasted with specialized taxonomic keys. Transverse fragments 1 cm thick were fixed in a mixture of formalin, alcohol, and acetic acid. These were subsequently dehydrated using an ethanol series, clarified in Xylene, and finally embedded in Paraplast plus® to obtain 5 μm sections. Schiff’s periodic acid reaction (PAS) was used to detect structural and reserve polysaccharides, Ruthenium Red for pectins, Ponseau S and Lacmoid for callose, ferric chloride for polyphenols, Sudan Black for lipids and Uvitex 2B-Hematoxylin for chitin. The sections were observed using a Nikon 80i eclipse® pho-ton microscope, with Uvitex 2B-Hematoxylin-stained sections examined by epifluorescence using a UV-2A filter. For the observation and description of the samples by scanning electron microscopy, healthy and infected leaves were fixed and dehydrated in 100 % methanol, critical point dried, and coated with gold. Results:H. macrophylla leaves are isobilateral and homobaric, with adaxial and abaxial epidermis of a single cellular layer. The palisade parenchyma consists of a layer of short cells, while the spongy parenchyma forms 6 to 7 cellular layers. All vascular bundles in the leaf blade are closed collaterals. Abundant idioblasts with raphides may be observed in the mesophyll, and starch is the main reserve carbohydrate present in the tissues. The leaves are hypostomatic and exhibit a paracytic pattern of superficial stomata which possess large substomatal cavities. The morphological data observed indicate that the mycopathogen is related to the genus Erysiphe. The epidermal cells affected by the pathogen exhibit thickened walls, granular cytoplasm, and papillae or cell wall appositions in the outer periclinal walls. With the deterioration of the epidermis, the underlying tissues are affected and become necrotic. Histochemical test indicate that infected plants thicken and reinforce their epidermal cell walls with primary wall materials; primarily cutin, pectins, and callose. When stained with Sudan Black, the presence of dark-colored agglomerates in the cytoplasm of epidermal cells may be related to plant defense mechanisms; and those observed in mesophilic cells to the disorganization of membrane systems. Polyphenols accumulate in the cytoplasm of infected epidermal cells. The fungal material present in epidermal tissues was clearly differenti-ated when stained with fluorochrome to detect chitin. Conclusions: Species of the genus Erysiphe are causative agents of powdery mildew in H. macrophylla. Necrosis of the epidermal cells is observed in response to the mycopathogen, possibly due to hypersensitive response.
Acceso abierto
Alteraciones histopatológicas causadas por la roya puccinia nakanishikii (Pucciniales: pucciniaceae) en plantas de cymbopogon citratus (poaceae)
(2020-02-13) Rincón-Barón, Edgar Javier; Gutierrez-Rodriguez, Ana Mariany; Guerra-Sierra, Beatriz Elena; Espinosa Matías, Silvia; Microbiota
Histopathological alterations caused by Puccinia nakanishikii rust (Pucciniales: Pucciniaceae) in Cymbopogon citratus (Poaceae) plants. Introduction: Histopathological and histochemical aspects linked to the attack of fungal rusts to plants, as well as its relation with the different spore stages are topics rather scarce in the scientific literature. Objective: To describe and analyze the histopathological and histochemical aspects of Cymbopogon citratus and its relation with the different stages of the spores from the rust fungi Puccinia nakanishikii. Methods: During the months April and August 2013, leaves healthy and infected by Puccinia nakanishikii were collected in the Northwestern scarp of the Bucaramanga-Colombia plateau. The samples with injuries on diverse developmental stages were fixated and processed according to the standard protocols for embedding and sectioning in paraffin and resin. Sections obtained from paraffin (5-7 μm) were stained with Safranin-Alcian blue and Alcian blue-Hematoxylin. On the other hand, sections obtained from resin (0.5 μm) were stained with Toluidine blue. Further, freehand sections were obtained for an autofluorescence analysis. The observations and photographic record were done via photonic microscope and epifluorescence microscope. For the observations via scanning electron microscopy (SEM), the samples were fixated in Glutaraldehyde, dehydrated with 2,2 dimethoxypropane, then desiccated to critical point and finally coated with gold. Results:The leaves are generally hypostomatic, with long and short epidermic cell forming parallel rows and showing unicellular prickle trichomes and micro-trichomes. The abaxial surface is covered by epicuticular wax forming a dense layer. The adaxial epidermis is formed by groupings of bulliform cells and epidermal cells with rectangu-lar or squared contour. In the mesophyll, there is no differentiation between palisade and spongy parenchyma, its anatomy reflects the C4 metabolism. The formation of uredosori and teliosori both hypophyllous was observed. Urediniospores are the reinfecting agents phase, they have 4-5 equatorial germ pores and echinulate wall. Teliospores have smooth wall and a persistent pedicel. The urediniospores form a germ tube, generally on the abaxial leaf surface, these tubes develop towards the stomata reaching the mesophyll interior. No appressorium were observed. The epidermis limiting the uredosorus detaches due the development and pressure that exert both the urediniospores and capitate paraphyses. As the infection progresses, autofluorescense of the chloro-phyll is lost and the cells undergo necrotic processes. Afterwards, the phloem collapses and the xylem becomes slightly disorganized. At this moment, the infection is extended along the whole leaf blade, resulting in the leaf death and the plant defoliation. On advanced stages of the infection, the uredosori showed pycnidia, probably belonging to the hyperparasite Sphaerellopsis, these structures were closely associated to the rust infected tissues. Conclusions:Puccinia nakanishikii develops on the leaves of Cymbopogon citratus producing uredosori and teliosori. Urediniospores are the reinfective stage, teliospores were only observed at late stages of the infection. The epidermis and photosynthetic tissue are severely affected by cell necrosis. The vascular tissues are deeply affected on the advances stages of the infection.
Acceso abierto
Analysis of labour market needs for engineers with enhanced knowledge in renewable energy in some European and Latin-American Countries
(Elsevier Inc., 2019, 2019-01) Serna Suárez, Iván David; Comodi, Gabriele; Cioccolanti, Luca; Mahkamov, Khamid; Penlington, Roger; Lapuerta, Magin; Hernández, Juan José; Silva Lora, Electo Eduardo; Venturini, Osvaldo; Melian Cobas, Vladimir Rafael; Escobar Palacio, José Carlos; Gaudêncio, Francisco; Freires, Mendonça; Andrade Torres, Ednildo; Mendes da Silva, Julio Augusto; Kafarov, Viatcheslav; Chacón Velasco, Jorge Luis; Solano Martinez, Javier Enrique; Lizarazo Salcedo, Gladys Yolanda; Lesme Jaen, Rene; Imbert González, Josue; Fernandez, Maria; García Faure, Luis Jerónimo; Oliva Merencio, Deny; Pereda Reyes, Ileana; Morales Salas, Joel; Cisneros Ramírez, Cesar
One of the main challenges related to the renewable energy labour market is that of human capital and as a consequence the educational profile of future employees is of paramount importance. Unfortunately, the skill level gained at University does not always fit with the practical needs of industry thus reducing the benefit-cost ratio of new employees and slowing down the programme aims at improving the renewable energy engineering curriculum at different university levels in several Universities of Latin America and Europe. In order to better appreciate the potential impact of the project, a survey on the labour market need for specialists with enhanced knowledge and skills in renewable and sustainable energy technologies has been conducted in the related EU and Latin America countries. More precisely, 60 organizations have been interviewed and almost 70% of them are interested in employing engineers with enhanced knowledge on renewable energy in the next three years. The analysis has shown significant discrepancies between EU and Latin American organizations. In fact, while future employees in EU countries will be mainly related to solar energy and management, the former together with wind and biomass will represent the main renewable energy working sector in Latin American countries. Moreover, MSc level will be the most demanded in EU while bachelor education seems to satisfy the future industry requirements in Latin America. Despite each country having its own needs, the research carried out under this EU project confirms the potential of renewable energy education on the global labour market in the near future.
Acceso abierto
Analysis of the Formal/Informal Wage Inequalities in Colombia: A Semiparametric Approach
(Journal of Applied Social Science, 2021-03-01) Ramoni-Perazzi, Josefa; Orlandoni-Merli, Giampaolo; Cibas
Informality is a common problem in Colombia, with almost 50 percent of the workers employed in this sector. This may be a solution for unemployment, but it is a lose/lose game unless the individuals have a comparative advantage in the informal sector. This article uses information from the Colombian Great Integrated Household Survey (GIHS) to analyze the wage gap between formal and informal urban sectors in two different periods, 2008:4 and 2017:4, using a semiparametric approach. Kernel density functions by groups are estimated; counterfactuals are generated by weighting wages of informal sector workers by their probability of working in the formal sector, to estimate how much an informal sector worker could make if treated as formal, according to his characteristics. The results indicate that only some groups (self-employed and some entrepreneurs) are better off if formalized.
Acceso abierto
Análisis de la duración del desempleo y el destino de los desempleados en la República Bolivariana de Venezuela
(2017-08) Ramoni Perazzi, Josefa; Orlandoni Merli, Giampaolo; Sinha, Surendra Prasad; Torres Rivas, Elizabeth; Zambrano, Angel
Si bien resulta contradictorio, las cifras ofciales en materia de desempleo y actividad económica en la República Bolivariana de Venezuela muestran simultáneamente una marcada tendencia a la baja. La reducción del desempleo en un período de recesión económica es posible si este se esconde detrás de la informalidad o del abandono de la búsqueda de trabajo. A partir de la estimación de máxima verosimilitud de matrices markovianas homogéneas aplicadas a datos de la Encuesta de Hogares por Muestreo del período comprendido entre el primer semestre de 2012 y el segundo semestre de 2013, en este estudio se analizan la duración media del desempleo y el destino de los desempleados. Los resultados indican que la larga duración del desempleo obliga a algunos individuos a abandonar la búsqueda de trabajo, por lo que dejan de pertenecer a la fuerza laboral, mientras que otros pasan al mercado informal.
Acceso abierto
Antifungal activity of acidic electrolyzed water against strawberry postharvest molds (Fragaria x ananassa Duch cv. Camarosa)
(2019-04-01) Guerra-Sierra, Beatriz Elena; Sandoval-Meza, Adriana Ximena; García-Sanchéz, Liliana Torcoroma; Microbiota
The aim of this word was to assess the in vitro antifungal activity of acidic electrolyzed water (AEW) and the required contact time to inhibit the development of post-harvest molds common in strawberry fruit. Ninetyfour strawberry samples were used. A five-fold assay in a randomized design was carried out using standard inoculum of fungal conidia, which were subjected to an array of contact times and AEW concentrations, using a controlled agitation (120 r.p.m) at 23°C. The conidia treated with AEW were grown on potato dextrose agar and their germination was evaluated. Mycelial growth of the treated samples was measured and compared against conidia control samples treated with distilled water instead of AEW. Botrytis cinerea and Rhizopus stolonifer were the most commonly isolated species at 54.25% and 28.72%, respectively. AEW inhibited conidia germination after 7 minutes of exposure. The AEW concentration required to inhibit conidia germination was 10 ppm and 50 ppm for R. stolonifer and B. cinerea respectively, a variance possibly due to the constitution of their cellular walls. A short exposure of AEW is able to inhibit post-harvest fungi growth, and is thus recommended as an efficient, economical, and environmentally sustainable sanitation agent, with the ability of extending the strawberry postharvest consumption period.
Acceso abierto
Antifungal effect of zinc oxide nanoparticles (ZnO-NPs) on Colletotrichum sp., causal agent of anthracnose in coffee crops
(2020-05-05) Mosquera-Sanchez, L.P.; Arciniegas-Grijalba, P.A.; Patiño-Portela, M.C.; Guerra–Sierra, Beatriz Elena; Muñoz-Florez, J.E.; Rodríguez-Páez, J.E.; Microbiota
Coffee cultivation around the world is affected by phytopathogenic fungi, among them Colletotrichum sp., the causative agent of anthracnose. In the present work, therefore, an in vitro study was carried out on the antifungal effect of zinc oxide nanoparticles (ZnO-NPs) obtained by a chemical route on Colletotrichum sp. To this end, the area of growth of the fungus exposed to the action of concentrations of 9 mmolL−1 (730 ppm), 12 mmolL−1 (980 ppm), and 15 mmolL−1 (1200 ppm) of ZnO-NPs was monitored and their behavior was compared with the effect of the fungicide, ciproconazole (positive control) as well as with a sample of the fungus that grew normally (negative control). The ZnO-NPs showed an appreciable percent inhibition of fungal growth, ~96% for the concentration of 15 mmolL−1 at 6 days, causing loss in the continuity of some hyphae and the formation of groups of hyphal structures. Additionally, the ZnO-NPs favored the formation of structures of compact appearance (similar to vacuoles) within the hypha, as well as decreasing the cytoplasmic space.
Acceso abierto
Antimicrobial activity of Ib-M peptides against Escherichia coli O157: H7
(San Francisco : Plos One, 2020., 2020-02-13) Prada Prada, Sergio Alfonso; Flórez Castillo, Johanna-Marcela; Farfán García, Ana Elvira; Guzmán, Fanny; Hernández Peñaranda, Indira Paola; Universidad de Santander; Iddya Karunasagar, Nitte University, INDIA
El desarrollo de nuevos péptidos antimicrobianos se ha convertido en una alternativa atractiva a los antibióticos convencionales debido a las crecientes tasas de resistencia a los fármacos microbianos. Ib-M corresponde a una familia de péptidos sintéticos catiónicos, de 20 aminoácidos de longitud, que han mostrado efecto inhibidor frente a la cepa no patógena Escherichia coli K-12. Este trabajo evaluó el potencial antimicrobiano de los péptidos Ib-M contra el E patógeno . coli O157: H7 utilizando una cepa de referencia y un aislado clínico. Los péptidos Ib-M mostraron actividad antibacteriana contra ambas cepas de E . coliO157: H7; la concentración mínima inhibitoria de los péptidos Ib-M osciló entre 1,6 y 12,5 µM y la concentración bactericida mínima osciló entre 3,7 y 22,9 µM, siendo Ib-M1 e Ib-M2 los péptidos que presentaron mayor efecto inhibidor. El ensayo de cinética de eliminación del tiempo mostró una reducción de la población bacteriana en más del 95% después de 4 horas de exposición a 1xMIC de Ib-M1. Se observó una baja citotoxicidad en células VERO con una concentración citotóxica del 50% en el rango de 197,5 a más de 400 μM. Todos los péptidos mostraron una estructura aleatoria en ambientes hidrófilos, excepto Ib-M1, y todos ellos pasaron a una estructura α-helicoidal cuando se incrementó la hidrofobicidad del medio. En conclusión, estos hallazgos apoyan el efecto antimicrobiano in vitro de los péptidos Ib-M contra las bacterias patógenas.E . coli O157: H7 y resultan ser moléculas prometedoras para el desarrollo de nuevas alternativas terapéuticas.
Acceso abierto
Aplicación de la metodología de series de tiempo en la estimación de los niveles de exportación de café de Colombia periodo 1958-2011
(2013-08-14) Pérez-Pulido, Miguel Oswaldo; Orlandoni-Merli, Giampaolo; Ramoni-Perazzi, Josefa
Un elemento fundamental para el sector cafetero colombiano, es saber a corto, mediano y largo plazo, el comportamiento de las exportaciones de café suave de Colombia, para conocer su relación en los procesos de ventas y producción. En concordancia con lo anterior, se realizó una evaluación de los niveles de exportaciones de café, en forma mensual desde inicios de 1958 hasta finales de 2008. Con el objetivo de desarrollar un modelo que permita caracterizar y obtener pronósticos sobre el comportamiento de las exportaciones de café realizadas en el país; para ello, se usó la metodología Box Jenkins, siguiendo las fases para los modelos ARIMA (Autoregresivo Integrado de Media Móvil). Los datos fueron tomados de la página web de la Federación Nacional de Cafeteros de Colombia. La serie bajo estudio mostró un comportamiento estacional, donde los primeros trimestres presentan los menores niveles del año, particularmente en febrero, mes que registra los niveles más bajos de exportaciones del año, estos niveles trimestralmente van incrementándose de forma paulatina hasta alcanzar el mayor nivel de exportaciones en el IV trimestre, específicamente entre Noviembre y Diciembre. Finalmente se obtuvieron los pronósticos entre los años 2009 y 2011, siguiendo un comportamiento estable respecto al periodo de validación de la muestra de la serie. Los datos fueron analizados utilizando el lenguaje R -PROJECT v 11.0.
Acceso abierto
Arbuscular mycorrhizal fungal association boosted the arsenic resistance in crops with special responsiveness to rice plant
(2022-01-05) Mitra, Debasis; Saritha, Boya; Janeeshma, Edappayil; Gusain, Poonam; Khoshru, Bahman; Abo Nouh, Fatma A.; Rani, Anju; Olatunbosun, Adeyemi N.; Ruparelia, Janki; Rabari, Aniruddh; Mosquera-Sánchez, Lyda P.; Mondal, Rittick; Verma, Devvret; Panneerselvam, Periyasamy; Das Mohapatra, Pradeep K.; Guerra-Sierra, Beatriz Elena; Microbiota
Arsenic (As) is a potentially toxic metalloid classified as a group 1 carcinogen, released in the soil environment because of natural as well as different anthropogenic activities. The presence of excess As content in soil and irrigation water enhances the As accumulation in rice grains. Millions of people who consume these contaminated grains are exposed to severe health issues. Increased arsenic uptake causes oxidative stress in plants, which combats by inducing the expression of several genes and signaling the biosynthesis of various antioxidants and phytochelatins. As toxicity reduces crop productivity, so it's critical to improve plant growth in As-contaminated environments while minimizing metal translocation to grains. Arbuscular mycorrhiza fungi (AMF) is considered a sustainable way to tolerate As toxicity. Organic pollutants metabolism by AMF, degradation of these soil contaminants by AMF exudation enzymes, and elimination of the pollutants by plant uptake and accumulation are the principal mechanisms of AMF mediated bioremediation. However, plant responses are established to vary with the host plant and the species of AMF. In our review, we showed that understanding the community composition, diversity, and gene regulation of AMF in the rice ecosystem played a critical role in maximizing As uptake and their potential in sustainable rice and other crops production. It has been reviewed that AMF has the potential to survive in an extremely As toxic condition and it potentially aids to improve the tolerance level of host plants.
Acceso abierto
Bacteria del Lago Mono propone paradigmas adicionales a la Biología Moderna
(2011-03) Florez, Alvaro M.; Quijano, Jairo; Orduz, Sergio
Acceso abierto
Bactericidal Effect of Entomopathogenic Bacterium Pseudomonas entomophila Against Xanthomonas citri Reduces Citrus Canker Disease Severity
(Frontiers in Microbiology, 2020, 2020-06-24) Villamizar, Sonia; Ferro, Jesus Aparecido; Caicedo Cepeda, Juan Carlos; Alves, L. M. C.; CIBAS
The bacterium Pseudomonas entomophila has been recognized as an exceptional species within the Pseudomonas genus, capable of naturally infecting and killing insects from at least three different orders. P. entomophila ingestion leads to irreversible gut damage resulting from a global blockage of translation, which impairs both immune and tissue repair systems in the insect intestine. In this study we isolated a P. entomophila bacterial strain from soil samples which displayed a strong activity against Xanthomonas citri subsp, citri (Xcc), the etiological agent of citrus canker disease. The antagonism potential of isolated bacteria against Xcc and its ability to reduce citrus canker severity was assessed both ex planta and in planta. Our findings show that pathogenicity assays in Citrus x limonia by pressure infiltration and spray with a mixture of P. entomophila and Xcc leaded to a significant reduction in the number of canker lesions in high susceptible citrus leaves, at 21 days post-infection. To the best of our knowledge this is the first report of antibacterial activity of P. entomophila against a phytopathogenic bacterium. Collective action of P. entomophila factors such as diketopiperazine production and the type 6 secretion system (T6SS) may be involved in this type of biological control of citrus canker. The results suggest that the P. entomophila strain could be a promising biocontrol agent acting directly against Xcc.
Acceso abierto
Bioconversion of post-culture wastewater from farm fisheries for the production of high-value algal biomass
(Journal of Physics: Conference Series, 2019-11-01) Gámez-Ortiz, Lorainis Paola; González-Soto, Maria Johana; Perez-Roa, M E; García-Martinez, J B; Urbina-Suarez, N A; Diaz Castañeda, Claudia-Elizabeth
Post-consumption water from inland fisheries possesses a tremendous environmental impact on aquatic ecosystems due to their high load of nutrients such as Nitrates, Phosphates, Urea and organic load. Due to the high cost of current water treatment systems, most of the waters from inland fisheries are discharged without any treatment, thus generating a significant environmental impact in rivers of different localities. Cyanobacteria are a group of photosynthetic microorganisms that can grow in different environments including wastewater. Among the most industrially exploited cyanobacteria, Spirulina (Arthrospira) maxima is the most relevant microorganism, due to its capacity to produce large quantities of protein and colourants (especially phycocyanins) for the food and feed industry. The objective of this project is to determine the maximum production capacity of Spirulina in post-consumption waters of fish farming as a system for the treatment of this type of water through the biological capture of the various nutrients and the production of biomass of industrial interest. S. maxima was produced on 3 different media (wastewater + Zarouk, wastewater + K2HPO4, NaNO3, NaHCO3 and wastewater without any modification) for 30 days. Results shown that S. maxima can effectively grow on wastewater supplemented with NaNO3 (2.5 g/L), NaHCO3 (16.8 g/L) and K2HPO4 (0.5 g/L) to obtain up to 1.18 g/L of total biomass and 0.23 g/L of phycocianins. The scaling of culture at 10 L showed a minimal reduction on final biomass and phycocyanin (1.05 and 0.21 g/L respectively), this result indicates that the production of biomass and phycobiliproteins from S. maxima in wastewater from inland fisheries can be a possible candidate for the simplification of biomass and high-value metabolites process production.
Acceso abierto
Biofertilizing potential of a fertilizer based on cienego and native microorganisms in corn seeds
(Journal of Physics: Conference Series, 2019-11-29) Diaz Castañeda, Claudia-Elizabeth; Daza, D.; Arámbula, Claudia-Ivonne
In the development of the productive process of stone aggregates, during the stage of washing and extraction of sludge from the decanter wells, a "cienego" sand is produced in an approximate quantity of 24.75 tons per day, of which only 10% per day is commercialized, the remaining 90% must be discarded, causing financial detriment, impact on the environment in terms of pollution by handling the product that is discarded, occupation of useful areas and landscape degradation, among other impacts negatively affecting the companies in the sector, and their environment. The objective of this research was to evaluate a fertilizer based on cienego and three native microorganisms (Azotobacter sp, 1 Azotobacter sp, 2 and Pseudomonas sp) in corn seeds. For this purpose, three native strains of diazotrophic bacteria were isolated from soil samples of oil palm crops in Tibú, located at Norte de Santander, Colombia, which were biochemically identified using traditional culture media. These isolates were inoculated into corn seeds in trays with sterile soil plus ciénego at 70/30 ratio respectively, and the plant growth-promoting effect was recorded every 4 days, by measuring morphological variables such as height, number of leaves, number of roots, length and germination rate. The results showed that Azotobacter sp, 2 treatment presented a higher production of roots, reached greater height (cm), number of leaves and germination rate in comparison to control treatment after 12 days of monitoring, besides directly influencing the percentage of organic matter in the substrate and elements such as calcium, potassium and phosphorus, allowing greater productivity and corn seed yield once these were germinated.
Acceso abierto
Biological Control of Citrus Canker
(London : IntechOpen, 2019., 2019-08-23) Caicedo Cepeda, Juan Carlos; Villamizar Cancelado, Sonia; Snjezana Topolovec-Pintaric
Citrus canker is a disease that affects the major types of commercial citrus crops. Xanthomonas citri subsp. citri, the etiological agent, reaches to mesophyll tissue through the stomata and afterward induces cell hyperplasia. Disease management has been based on both tree eradication and copper spray treatment. Overuse of copper for control of bacterial citrus canker has led to the development and prevalence of copper-resistant strains of Xcc. Several genera of both soil- and plant-associated bacteria became powerful tools in sustainable agriculture for control of Xcc and reduction of citrus canker disease severity. In this chapter we present bacteria able to interfere with quorum sensing as well to display antibacterial activity against Xcc by production of secondary metabolite. These bacteria may represent a highly valuable tool in the process of biological control and offer an alternative to the traditional copper treatment currently used for the treatment of citrus canker disease, with significant environmental, economic, and health implications worldwide.
Acceso abierto
Biopolymeric pellets of polyvinyl alcohol and alginate for the encapsulation of Ib-M6 peptide and its antimicrobial activity against E. coli
(Heliyon, 2019-05-29) Flórez Castillo, Johanna-Marcela; Ropero Vega, José Luis; Perullini, Mercedes; Jobbágy, Matias; CIBAS
The encapsulation of Ib-M6 antibacterial peptide in pellets of polyvinyl alcohol (PVA) and polyvinyl alcoholalginate (PVA-Alg) matrices was carried out in order to explore its controlled release and activity against Escherichia coli K-12. The pellets were obtained by combined ice segregation induced self-assembly (ISISA) and freezing-thawing methods and their microstructure was studied by scanning electron microscopy. Bromothymol blue was used as a model compound to study the transport mechanisms and release from pellets. The results show that there is a significant effect of the total concentration of PVA precursor solutions, the mass ratio of PVA of different molecular weights and the addition of alginate on the microstructure and transport properties of pellets. The antibacterial activity of Ib-M6 against Escherichia coli K-12 was not affected by the encapsulation in PVA pellets. However, the release of Ib-M6 from PVA-Alg pellets was not possible, probably due to the electrostatic interaction of positively charged Ib-M6 and negatively alginate structure. Nonetheless, the controlled release of Ib-M6 from polymeric matrices can be fitting by modifying parameters such as the concentration and type of polymer precursors.

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