Examinando por Autor "Guerra Sierra, Beatriz Elena"
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- PublicaciónAcceso abiertoActividad Antimicrobiana de Aceites Esenciales Derivados de Lippia alba Sobre los Odontopatógenos Candida albicans y Aggregatibacter actinomycetemcomitans(Universidad de Santander, 2021-11-26) Caicedo-Jiménez, Karen Alexandra; Guerra Sierra, Beatriz Elena; Quintero, Wendy LorenaEl presente estudio tuvo como objetivo evaluar la actividad antimicrobiana de aceites esenciales derivados de Lippia alba sobre Candida albicans y Aggregatibacter actinomycetemcomitans causantes de infecciones orales. Inicialmente, se evaluó la cinética de crecimiento de los microorganismos durante 48 h mediante espectrofotometría (600 nm), posteriormente se determinó la actividad antimicrobiana in vitro de aceites esenciales (AEs) derivados de L. alba y de sus terpenos bioactivos (óxido de cariofileno, citral y carvona) mediante microdilución en caldo (de forma individual y en combinación) y su actividad fungicida y bactericida. Los resultados fueron expresados como la concentración inhibitoria mínima (CIM) y el análisis estadístico se realizó mediante el uso del software (GraphPad Prism 5.0). Se encontró que los AEs del quimiotipo citral (F2 y F4) exhibieron la mejor actividad antimicrobiana (C. albicans: CIM 500μg/mL, concentración fungicida mínima (CFM) 1000 μg/mL; A. actinomycemtemcomitans: CIM 250 μg/mL y concentación bactericida mínima (CBM) 500 μg/mL; que las alcanzadas con los aceites del quimiotipo carvona y las referencias comerciales. Finalmente, los terpenos del quimiotipo citral (F2 y F4) evidenciaron la mejor interacción sinérgica in vitro contra la bacteria y (citral+OCN) para la levadura (CIF=0.41±0.11; μg/mL). Los resultados obtenidos representan una alternativa promisoria para el control de los microorganismos que causan la periodontitis.
- PublicaciónAcceso abiertoActividad antimicrobiana de hongos endófitos de plantas medicinales Mammea americana (Calophyllaceae) y Moringa Oleífera (Moringaceae).(Bucaramanga : Universidad de Santander, 2018, 2018-06-26) Mosquera Rivera, Wilmer G.; Guerra Sierra, Beatriz Elena; Criado Guerrero, Libeth-YajairaLas enfermedades infecciosas, son la causa principal de muertes en el mundo. En la actualidad, un factor preocupante, es el aumento de la resistencia bacteriana a los antibióticos, siendo esto un problema de salud pública. La Organización Mundial de la Salud (OMS) priorizó la investigación de nuevos antibióticos para el tratamiento de los patógenos multiresistentes. Por tal motivo es necesaria una búsqueda de nuevos nichos y hábitats de agentes antimicrobianos potencialmente eficaces. Siendo asi se evaluó la actividad antimicrobiana de los hongos endófitos de Mammea americana y Moringa Oleífera en Staphylococcus aureus (ATCC® 29213™) y Escherichia coli (ATCC® 25922™).Se llevó a cabo una metodología según un estudio experimental en 60 muestras vegetales. Se aislaron e identificaron hongos endófitos, se les evaluó su actividad antimicrobiana mediante ensayo dual in vitro a través de la presencia de halos de sensibilidad, posteriormente se realizaron recopilaciones continuas de biomasa de los endófitos para obtener extractos de las moléculas bioactivas, a las cuales se les midió la Concentración Mínima Inhibitoria (CMI ), concentración mínima bactericida (CMB) y citotoxicidad. Las pruebas de antagonismo y sensibilidad in vitro, permitieron preseleccionar 14 hongos con actividad antimicrobiana, de la clase Ascomycete y Deuteromycete, aislados en mayor proporción de semillas y hojas. La mayoría de sus extractos presentaron inhibición tanto de las cepas sensibles como de las resistentes para las dos bacterias. Considerando los resultados de las CMI, CMB y citotoxicidad, se demostró que los hongos endófitos poseen características bactericidas sin ocasionar daño alguno. Las pruebas de sensibilidad in vitro permitieron seleccionar y conocer los endófitos con posibles metabolitos secundarios con propiedades antimicrobianas y no tóxicas, por esta razón los hallazgos encontrados son importantes para continuar con investigaciones sobre los mecanismos de acción, resaltando que el aislamiento de endófitos en estas plantas es escaso o desconocido
- PublicaciónAcceso abiertoDeterminación de la actividad acaricida de extractos vegetales y otros compuestos sobre Schizotetranychus hindustanicus en cultivo de Lima Tahití (Citrus ×latifolia Tanaka ex Q. Jiménez).(Bucaramanga : Universidad de Santander, 2019, 2019-12-16) Osorio Alvarado, Carlos Enrique; Ortiz Meneses, Fredy Alejandro; Guerra Sierra, Beatriz ElenaLemon Tahiti (Citrus × latifolia Tanaka ex Q. Jiménez) crops cover a large geographical area in Colombia, since the multiple uses of its fruit generate various benefits and its export presents a high degree of economic activity in the country. For these reasons, monitoring these crops of any agent that affects them becomes one of the main challenges for farmers. Schizotetranychus hindustanicus is one of the pests that affects citrus trees causing circular whitish spots on leaves and fruits, and in Colombia its presence has been reported in various departments, therefore farmers choose to use techniques based on substance use considered as the precursors of pesticides when these pests appear. Due to this, in the present study it was tried to carry out control strategies based on organic extracts derived from the Azadirachta indica (Neem) plant, since its insecticide properties have been demonstrated through various studies, as well as the Kumulus that It has been widely used but has not been evaluated in Schizotetranychus hindustanicus in Tahiti Lemon crops. Previously, the mite was identified through the identification character, which corresponds to the edeago in males. Two doses of Azadiractin-based, commercial and Emulsified compounds were evaluated in vitro; The highest mortality was presented by Emulsified Neem and Kumulus with values of 93.30 and 97.22% respectively at 72 hours. These treatments were evaluated in vivo. Subsequently, the LD50 of the Emulsified Neem was determined, which showed that at a concentration of 1.07%, the mortality of half the population at 24 hours is presented. Finally, Schizotetranychus hindustanicus was identified as the species of interest, which was inhibited by 2 of the organic compounds evaluated.
- PublicaciónAcceso abiertoHongos Endófitos de Lima Tahití (citrus citrus x latifolia) y su Utilidad en el Biocontrol de Colletotrichum acutatum Causante de Antracnosis(Bucaramanga : Universidad de Santander, 2021, 2021-09-06) Muñoz Guerrero, Jaider; Guerra Sierra, Beatriz ElenaColletotrichum acutatum es uno de los agentes causales de la antracnosis que se caracteriza por lesiones en hojas y sobre todo en flores y frutos, de varios cultivos como los cítricos. El patógeno normalmente ataca a las flores, provocando graves lesiones. En condiciones muy favorables, puede afectar los botones florales y los frutos pequeños, provocando una pudrición completa y una caída prematura, lo que resulta en importantes pérdidas económicas en las cosechas. Los objetivos de este trabajo fueron: 1) identificar la diversidad de hongos endófitos en muestras vegetales de lima Tahití; 2) evaluar la capacidad antagonista de estos hongos frente al fitopatógeno Colletotrichum acutatum C-100 en pruebas duales; 3) evaluar la capacidad de diferentes especies de hongos endofíticos para controlar flores con antracnosis inducida y 4) identificar molecularmente las cepas fúngicas con mayor actividad inhibitoria para Colletotrichum acutatum. Se obtuvieron 138 aislados fúngicos a partir de 486 fragmentos de ramas, hojas y frutos; de las cuales se identificaron 15 morfoespecies. Se encontró una mayor frecuencia de morfoespecies en ramas y hojas, con un nivel de diversidad comparable con lo reportado en otras especies de cítricos. De las 15 morfoespecies, 5 se probaron contra Colletotrichum acutatum en pruebas de antagonismo, lo que resultó en un hallazgo de inhibición positiva. Solo 2 hongos endofíticos de las pruebas de antagonismo demostraron una alta inhibición del fitopatógeno, por lo que se utilizaron en pruebas in vivo con flores de lima Tahití, aplicadas en una solución de esporas. Estos hongos fueron identificados molecularmente como Xylaria adscendens y Trichoderma atroviride, los cuales redujeron considerablemente las lesiones provocadas por el fitopatógeno en estas pruebas in vivo. El hallazgo de que los endófitos reaccionaran de manera antagónica contra Colletotrichum acutatum, demuestra su capacidad y utilidad como biocontroladores de antracnosis, convirtiéndolos en especies promisorias para futuras investigaciones en campo y desarrollo biotecnológico, apuntando a una agroindustria que requiere sostenibilidad ambiental.
- PublicaciónAcceso abiertoImpacts of Arbuscular Mycorrhizal Fungi on Rice Growth, Development, and Stress Management With a Particular Emphasis on Strigolactone Effects on Root Development(2021-03-15) Debasis, Mitra; Guerra Sierra, Beatriz Elena; Bahman, Khoshru; De Los Santos Villalobos, Sergio; Belz, Claudia; Chaudhary, Priya; Shahrig, Faride Noroozi; Rihab, Djebaili; Nurudeen, Olatunbosun Adeyemij; El-Ballatk, Enas M.; El-Esawik, Mohamed A.; Moradic, Shokufeh; Mondall, Rittick; Senapati, Ansuman; Panneerselvam, Periyasamy; Das Mohapatra, Pradeep K.; MicrobiotaArbuscular mycorrhizal fungi (AMF) are widely distributed soil-borne microorganisms, which have a symbiotic relationship with several terrestrial plants. They play a key role in plant growth promotion and development, plant nutrient homeostasis, soil nutrient management, and induction of plant defense mechanisms against pest infestation and disease incidences. This interaction of AMF with rice plants has been studied in great detail, providing distinct perspectives on the natural basis of nutrient transport, stress management, improvement of soil health, and induction of systemic plant resistance. This review highlights the responses of (i) AMF interaction with rice plants, (ii) AMF colonization and sporulation potential in rice rhizosphere, (iii) AMF species as a source of inoculum for rice production, (iv) AMF for rice plant maintenance and durability, and (v) AMF responses to other soil microorganisms. Additionally, a new class of phytohormones known as strigolactone (SLs) has been briefly described covering the various forms of analogs, isomers, and membrane transporters. The role of SLs in pre-symbiotic molecular talks, induction of energy metabolism in mitochondria, spore germination, stimulation of hyphal branches, and the relationships of SLs synthesis with soil nutrient content provides in-depth insights into the mechanisms involved in improving AMF interactions with rice plants.
- PublicaciónAcceso abiertoIndigenous arbuscular mycorrhizal fungi in oil palm soils in Colombia(2013-09) Guerra Sierra, Beatriz Elena; Serge, Sokolski; Dion, PatriceGenerally monocultures have replaced tropical forests and other ecosystems, causing big changes and little is known about the influence of the practice of monoculture in density and biodiversity of mycorrhizal fungi (AMF) species. Spore production is highly depend of physiologycal parameters of the AMF and on environmental conditions, however it is known that in nutrient-poor soils of the humid tropics many plants are obligate mycotrophs or ecologically dependent on AMF. In Oil palm (Elaeis guineensis Jacq), the limited development of their root system and field observations of high levels of mycorrhizal colonization, suggest that this crop benefits greatly from the symbiosis.[1]Isolation of soil spores and subsequent microscopic examination is a routine procedure in the recognition of AMF species, however the study of walls by light microscopy is a difficult task; interpretation depends on several factors such as the type of microscope and lighting mounting means and observer experience.Based on the morphological characteristics of the AMF described approximately 200 species (2).As a complement to morphological studies AMF wall light microscopy has been used transmission electron microscopy (TEM) and scanning electron microscopy (SEM), however the publications in this field are limited. Another limitation of morphologycal identification is the fact that field- collected spores are often parasitized or degraded and therefore unidentifiable. A methodology for increased healthy spores are AMF trap cultures ,soil samples from the field site are brought into contact with suitable plant hosts of AMF under controlled conditions in order to propagate the species, additionally the plant species used in the trap cultures may have an influence on which AMF are detected , aditionaly the molecular identification is a good tool for the identification of AMF, almost all identification systems for AMF are based on the ribosomal DNA (rDNA) , this is highly polymorphic in single spores of AMF. The aim of this study was to determine the initial density of native mycorrhizal fungi spores in soils of oil palm monocultures, and the identification of AMF species increased in trap cultures under controlled greenhouse conditions . Mycorrhizal fungi spores were identified using optical and scanning microscopy, and molecular analysis was useful for identifying some species of Glomus.
- PublicaciónAcceso abiertoNueva reacción en cadena de la polimerasa múltiple para el diagnóstico específico de especies implicadas en la candidiasis humana(2017-06) García Sánchez, Liliana Torcoroma; Luna, Liany Johanna; Velasco, Tania Katherine; Guerra Sierra, Beatriz ElenaIntroduction: Candidiases is a group of opportunistic infections caused by yeasts belonging to the genus Candida. Candida albicans is the most prevalent species in both superficial and deep infections, however, the clinical importance of non-albicans Candida has increased during the last decade, driving an urgent need for diagnostic tests that allow for species-level resolution and selection of the optimum therapeutic approach.Objective: To design and to optimize a new multiplex PCR assay for the simultaneous identification of the five most relevant species of Candida involved in human candidiasis etiology.Materials and methods: For primers design, the physical and thermodynamic restrictions that affect multiplex PCR performance were analyzed using Gene Runner and Mult-PSOS. As templates, the internal transcribed region 2 (ITR2) was selected for C. albicans (AJ249486.1), and topoisomerase II (TOPII) for C. parasilopsis (AB049144.1), C. krusei (AB049139.1), C. tropicalis (AB049141.1), andC. guillermondii (AB049145.1). We used ATCC strains of all these five species and clinical isolates as templates.Results: We designed ten oligonucleotides for the simultaneous amplification of the Candida species. The electrophoresis band profile was: C. albicans (206 bp), C. guillermondii (244 bp), C. tropicalis (474 bp), C. parasilopsis (558 bp), and C. krusei (419 bp). Conclusion: The new multiplex PCR assay designed in this study allowed a simultaneous and efficient amplification of the amplicons corresponding to the five species of Candida under study, with an adequate resolution in standard agarose gel.
- PublicaciónAcceso abiertoPhytoremediation of heavy metals in tropical soils an overview(2021-03-27) Guerra Sierra, Beatriz Elena; Muñoz Guerrero, Jaider; Sokolski, Serge; MicrobiotaThe geomorphological characteristics of the materials inherent in tropical soils, in addition to the excessive use of fertilizers and pesticides, industrial waste and residues, and novel pollutants derived from emerging new technologies such as nanomaterials, affect the functionality and resilience of the soil-microorganism-plant ecosystem; impacting phytoremediation processes and increasing the risk of heavy metal transfer into the food chain. The aim of this review is to provide a general overview of phytoremediation in tropical soils, placing special emphasis on the factors that affect this process, such as nanoagrochemicals, and highlighting the value of biodiversity among plant species that have the potential to grow and develop in soils impacted by heavy metals, as a useful resource upon which to base further research
- PublicaciónAcceso abiertoSimbiosis micorrízica arbuscular y acumulación de aluminio en brachiaria decumbens y manihot esculenta(2012-07) Guerra Sierra, Beatriz Elena; Chacón, Martha RocioOil palm (Elaeis guineensis Jacq) soils from-Santander Puerto Wilches-Colombia, have low fertility, high aluminum saturation and low density of mycorrhizal fungal spores. Behavior mycorrhizal symbiosis was evaluated XVLQJ QDWLYH VRLOV ZLWK P\FRUUKL]DH 0$ DQG VWHULOH VRLOV ZLWKRXW mycorrhizae (MA -) using Brachiaria decumbens and Manihot esculenta, both plants have high mycotrophy and ion binding capacity of aluminum. Variables were spore density, percentage of mycorrhizal colonization, biomass and root length, concentration of aluminum at leaf and root. Was performed (ANOVA) with a two-way general linear model. There were mycorrhizal colonization rates exceeding 70% in B. decumbens in soils with concentrations of 0,6 and 1,4 meq/100 g of aluminum. M. esculenta establishedmycorrhizationat 50% in all four soils. Spores were increased up to 200% in the two hosts plants. Aluminum concentrations were higher in mycorrhizal roots, while leaf-level values were lower.
- PublicaciónAcceso abiertoZnO-based nanofungicides : Synthesis, characterization and their effect on the coffee fungi Mycena citricolor and Colletotrichum sp.(2019-05) Arciniegas Grijalba, P.A.; Patiño Portela, M.C.; Mosquera Sánchez, L.P.; Guerra Sierra, Beatriz Elena; Muñoz Flórez, Jaime Eduardo; Erazo Castillo, L.A.; Rodríguez Páez, J.E.mical route and a ZnO-based nanobiohybrid obtained by green synthesis in an extract of garlic (Allium sativum). To find out the characteristics of the materials synthesized, X-ray diffraction (XRD), IR spectroscopy and absorption in UV–Vis were used, as well as both scanning (SEM) and transmission (TEM) electron microscopy. The results showed that the samples obtained were of nanometric size (< 100 nm), with a predominance of the wurtzite crystal phase of ZnO and little crystallization of the nanobiohybrids. Their antifungal capacity on two pathogenic fungi of coffee, Mycena citricolor (Berk and Curt) and Colletotrichum sp. was also evaluated. Both nanomaterials showed an efficient antifungal capacity, particularly the nanobiohybrids, with ~97% inhibition in growth of M. citricolor, and ~93% for Colletotrichum sp. The microstructural study with high resolution optical (HROM) and ultra-structural microscopy (using TEM) carried out on the fungi treated with the synthesized nanomaterials showed a strong nanofungicidal effect on the vegetative and reproductive structures and fungal cell wall, respectively. The inhibition of the growth of the fungi and micro and ultra-structural affectations were explained considering that the size of the nanomaterials allows them to pass easily through the cell membranes. This indicates that they can be absorbed easily by the fungi tested here, causing cellular dysfunction. Nanofungicide effects are also attributable to the unique properties of nanomaterials, such as the high surface-tobulk ratio of atoms and their surface physicochemical characteristics that could directly or indirectly produce reactive oxygen species (ROS), which affect the proteins of the cell wall.