Cuantificación de bacterias diazótrofas aisladas de suelos cacaoteros (Theobroma cacao L.), por la técnica de Número Más Probable (NMP)

Esta investigación tuvo como objetivo cuantificar bacterias diazótrofas y comparar fisicoquímicamente suelos rizosféricos de tres cacaotales (Theobroma cacao L.) del Departamento Norte de Santander, Colombia; para lo cual se caracterizaron, diferenciándose en área cultivada, manejo agronómico y edad del cultivo. A partir de diluciones seriadas de las muestras y empleando la técnica de Número Más Probable (NMP), en medios de cultivo semiselectivos (NFb, JMV, LGI, JNFb) semisólidos, se cuantificaron las diazótrofas, evaluando como positivo la formación de una película subsuperficial en el medio contenido en viales sellados; muestras pares se enviaron al laboratorio Bioambiental (UNET) para los análisis fisicoquímicos. Como resultado, las muestras evaluadas mostraron deficiencias en el porcentaje de materia orgánica y elementos como Potasio, Fósforo y Magnesio. Se reportaron estadísticamente diferencias altamente significativas en NMP. La mayor cuantificación de diazótrofas se reportó en la finca Florilandia, que se caracterizó por tener riego por goteo. La mayor cuantificación de diazotrófas se registró en los medios NFb y JMV, demostrándose una mayor presencia de los presuntos géneros Azospirillum sp. y Burkholderia sp. los cuales son fácilmente aislados de suelos rizosféricos, a diferencia de los géneros Herbaspirillum sp. y Gluconacetobacter sp. que por su carácter endófito suelen ser menos predominantes en este tipo de muestras. Se concluye además, que las características fisicoquímicas del suelo, la humedad y las relaciones climáticas al momento de la toma de las muestras, condicionan la cantidad de exudados de las raíces y por tanto son factores que condicionaron la presencia de diazótrofas en las muestras.Palabras clave: Azospirillum, Burkholderia, cacao, rizósferaThe objective of this research was to quantify diazotrophic bacteria and compare physicochemically rhizospheric soils of three cocoa plantations (Theobroma cacao L.) in Norte de Santander Department, Colombia; for which they were characterized, differing in cultivated area, agronomic management and crop age. From serial dilutions of the samples and using the technique of Most Probable Number (MPN), In semisolid culture media (NFb, JMV, LGI, JNFb), the diazotrophs were quantified, evaluating as positive the formation of a subsurface film in the medium contained in sealed vials; equal samples were sent to the Bioambiental laboratory (UNET) for physicochemical analyzes. As a result, the evaluated samples showed deficiencies in the percentage of organic matter and elements such as Potassium, Phosphorus and Magnesium. Statistically highly significant differences in MPN were reported. The highest quantification of diazotrophs was reported in the Florilandia farm, which was characterized by drip irrigation. The highest quantification of diazotrophs was recorded in the media NFb and JMV, demonstrating a greater presence of the presumed genera Azospirillum sp. and Burkholderia sp. which are easily isolated from rhizospheric soils, unlike the genera Herbaspirillum sp. and Gluconacetobacter sp. which by their endophytic character tend to be less predominant in this type of samples. It is also concluded that the physicochemical characteristics of the soil, humidity and climatic relationships at the moment of sampling, condition the amount of root exudates and therefore are factors that conditioned the presence of diazotrophs in the samples.Keywords: Azospirillum; Burkholderia; cocoa; rhizosphere

Repercusiones de la pandemia del Covid-19 (SARS-COV2) en la educación y salud

Covid-19 pandemic has transformed the dynamics of our society, with global consequences. For this reason, from the documentary research approach, to obtain relevant data on the effects of the Covid-19 pandemic in the areas of health and education. Methodologically, the information was searched through different databases such as Science Direct, PubMed, Medline, Redalyc, Scielo, Springerlink and Scopus. Documents published in Spanish and English taken as the inclusion criteria. Subsequently, through the analysis of the information, the theoretical elements that allowed to make interpretative statements about the subject of study were found. Regarding the education sector, it is clear the impact that Covid-19 has generated at a global level, it has involved changes in educational methodology at all levels, from basic education to higher education. The Covid-19 pandemic has generated repercussions in all the areas of human life; the affectation of the different fields is, directly and indirectly, related to the education and health of the population, in turn, this is a situation that has led societies to an unprecedented adaptation process that will leave lessons and sequels at a global level.El covid-19 ha transformado la dinámica de nuestra sociedad, con consecuencias a nivel mundial. Por este motivo, desde el enfoque de la investigación documental se buscó obtener datos relevantes acerca de los efectos de la pandemia del Covid-19 en los ámbitos de educación y salud. Metodológicamente, se realizó la búsqueda de la información a través de diferentes bases de datos como Science Direct, PubMed, Medline, Redalyc, Scielo, Springerlink and Scopus. Como criterios de inclusión se tomaron los documentos publicados en inglés y español. Seguidamente, se analizó la información, el cual permitió encontrar los elementos teóricos que permitieron hacer afirmaciones e interpretación sobre el objeto de estudio. En el sector de la educación es claro el impacto que ha generado el Covid-19 a nivel global, ha implicado cambios de metodología educativas en todos los niveles, desde la educación básica hasta la educación superior. La pandemia del Covid-19 ha generado repercusiones en todos los sectores de la vida humana; la afectación de los diferentes ámbitos se relaciona de forma directa e indirectamente con la educación y la salud de la población, a su vez, esto es una situación que ha llevado a las sociedades a un proceso de adaptación sin precedentes que dejará enseñanzas y secuelas a nivel global. &nbsp

Caracterización molecular y detección de genes blaCTX-M grupos 1 y 9 en Klebsiella pneumoniae resistentes a ceftazidima, en un hospital de San José de Cúcuta, Colombia

Background: The expression of CTX-M β-lactamases belonging to groups 1 and 9 in Klebsiella pneumoniae produces high levels of resistance to ceftazidime, and they have a wide distribution worldwide. Aim: To identify and characterize the blaCTX-M-Group1 and blaCTX-M-Group9 genes in K. pneumoniae isolates resistant to ceftazidime in a hospital in San José de Cúcuta, Colombia. Material and Methods: Primers were designed for the identification of K. pneumoniae and blaCTX-M genes by PCR. Subsequently, the genetic relationship of these isolates was analyzed by REP-PCR. Results: A 38% of the 24 isolates identified by PCR as K. pneumoniae showed blaCTX-M-3. blaCTX-M-15 y blaCTX-M-32 genes (Group CTX-M-1) and 42% blaCTX-M14. blaCTX-M-24 y blaCTX-M-27 genes (Group CTX-M-9). The phylogenetic analysis grouped the K. pneumoniae isolates into 4 clusters, showing correlation in clusters I, II and IV, when comparing the genetic profiles with the type of sample and group of genes. Discussion: We found a similar frequency of blaCTX-M-Group 1 and blaCTX-M-Group 9 genes in isolates of K. pneumoniae resistant to ceftazidime. The correlation between the REP-PCR with the CTX-M groups and the type of sample revealed the presence of three clonal patter

Identificación de genes Cry1 en aislados de Bacillus thuringiensis y su efecto tóxico contra Milax gagates, plaga en lechuga (Lactuca sativa)

Milax gagates is one of the main pests in the cultivation of lettuce, causing considerable economic losses. Control with molluscicides totally or partially eliminates the pest but generates a negative impact on the environment due to their high toxicity. Biological management also allows controlling the pest, but in a specific and safe way for the environment. Therefore, the objective of this work was to evaluate the toxic effect of Bacillus thuringiensis, with Cry1 genes, against M. gagates by means of a bioassay. Seventy-five soil samples were taken from several municipalities in Norte de Santander, Colombia, from where 58 isolated colonies of B. thuringiensis with similar characteristics were obtained. Of these colonies, five showed the presence of Cry1 genes, and were those used in the bioassays together with the control B. thuringiensis var. Kurstaki. The treatments caused 90-100 % lethality to M. gagates at a concentration of 500 μg∙mL-1. The calculated LD99 suggests the use of 820 μg∙mL-1 of the biopreparate to obtain 100 % lethality with any of the five isolates studied.Milax gagates constituye una de las principales plagas en el cultivo de lechuga causando considerables pérdidas económicas. El control con molusquicidas elimina total o parcialmente la plaga, pero genera un impacto negativo en el ambiente por su alta toxicidad. El manejo biológico también permite el control de la plaga, pero de manera específica e inocua para el ambiente. Por ello, el objetivo de este trabajo fue evaluar el efecto tóxico de Bacillus thuringiensis, con genes Cry1, contra M. gagates mediante la elaboración de un bioensayo. Se tomaron 75 muestras de suelo de varios municipios del Norte de Santander, Colombia, de donde se obtuvieron 58 colonias aisladas de B. thuringiensis con características similares. De estas colonias, cinco evidenciaron la presencia de genes Cry1, y fueron las empleadas en los bioensayos junto con el control B. thuringiensis var. Kurstaki. Los tratamientos presentaron letalidad ante M. gagates de entre 90 y 100 % a una concentración de 500 μg∙mL-1. La CL99 calculada sugiere el uso de 820 μg∙mL-1 del biopreparado para obtener 100 % de letalidad con cualquiera de los cinco aislados estudiado

The information and communication technologies in the administration of the processes and systematization

The objective of the research is to describe how Information and Communication Technologies allow not only to organize in the strain bank microorganisms obtained from different environments for application in academic, research and extension processes, but also to continue characterizing microorganisms obtained from different environments for application in all these processes. Results it has been observed that the absence of Information and Communication Technologies as a strategy to organize and select viable microorganisms already identified can continue to be used and applied in industrial processes, environmental, agricultural food and pharmaceutical industry, among others, has caused the dispersion and loss of information, hindering the easy and timely recovery of the products generated, not being recorded and stored information that is generated. The "Laboratorio de Investigaciones en Microbiología Avanzada y Biología Aplicada" must create its own website and web application that allows strengthening the strain bank, allowing them to be visible with the production generated there

Quantification of diazotrophs bacteria isolated from cocoa soils (Theobroma cacao L.), by the technique of Most Probable Number (MPN)

The objective of this research was to quantify diazotrophic bacteria and compare physicochemically rhizospheric soils of three cocoa plantations (Theobroma cacao L.) in Norte de Santander Department, Colombia; for which they were characterized, differing in cultivated area, agronomic management and crop age. From serial dilutions of the samples and using the technique of Most Probable Number (MPN), In semisolid culture media (NFb, JMV, LGI, JNFb), the diazotrophs were quantified, evaluating as positive the formation of a subsurface film in the medium contained in sealed vials; equal samples were sent to the Bioambiental laboratory (UNET) for physicochemical analyzes. As a result, the evaluated samples showed deficiencies in the percentage of organic matter and elements such as Potassium, Phosphorus and Magnesium. Statistically highly significant differences in MPN were reported. The highest quantification of diazotrophs was reported in the Florilandia farm, which was characterized by drip irrigation. The highest quantification of diazotrophs was recorded in the media NFb and JMV, demonstrating a greater presence of the presumed genera Azospirillum sp. and Burkholderia sp. which are easily isolated from rhizospheric soils, unlike the genera Herbaspirillum sp. and Gluconacetobacter sp. which by their endophytic character tend to be less predominant in this type of samples. It is also concluded that the physicochemical characteristics of the soil, humidity and climatic relationships at the moment of sampling, condition the amount of root exudates and therefore are factors that conditioned the presence of diazotrophs in the samples

Aprimoramento da metodologia do teste de tetrazólio utilizando diferentes pré-tratamentos em sementes do gênero Epidendrum (Orchidaceae)

The aim of the present study was to determine the most suitable pretreatment to enhance the tetrazolium test in seeds of the Epidendrum genus. Initially, mature capsules were harvested at El Escorial village, in the municipality of Pamplona, ​​Colombia. Subsequently, the seeds were subjected to five pretreatments: deionized water, 0.5% NaClO, 1.0% NaClO, 10.0% sucrose and a control group. Using the syringe method with cloth filter, the seeds were rinsed with distilled water and subjected to two concentrations of tetrazolium solution (0.25%, 1.0%) and three exposure times (6 h, 24 h and 48 h). Finally, the tetrazolium viability test results were correlated with the in vitro germination test. It was found that the use of deionized water improves the efficiency of the tetrazolium test in seeds of Epidendrum fimbriatum and E. microtum; as in seeds of E. elongatum when using 1.0% tetrazolium for 24 h. Similarly, a high correlation was found between viability and germination, using deionized water and 10.0% sucrose, with homogeneous results with each otherO objetivo do presente estudo foi determinar o pré-tratamento mais adequado para aprimorar a metodologia do teste de tetrazólio em sementes do gênero Epidendrum. Inicialmente, cápsulas maduras foram coletadas na vila de El Escorial, no município de Pamplona, Colômbia. Em seguida, as sementes foram submetidas a cinco pré-tratamentos: água deionizada, NaClO a 0,5%, NaClO a 1,0%, sacarose a 10,0% e um controle. Utilizando o método de seringa com filtro de pano, as sementes foram lavadas com água destilada e submetidas a duas concentrações de solução de tetrazólio (0,25% e 1,0%) e três tempos de exposição (6 h, 24 h e 48 h). Finalmente, os resultados do teste de viabilidade do tetrazólio foram comparados ao teste de germinação in vitro. Verificou-se que o uso de água deionizada melhora a eficiência do teste de tetrazólio em sementes de Epidendrum fimbriatum e de E. microtum, assim como em sementes de E. elongatum ao usar 1,0% de tetrazólio por 24 h. Da mesma maneira, foi encontrada alta correlação entre viabilidade e germinação, utilizando água deionizada e 10,0% de sacarose, com resultados homogêneos

Sustratos inoculados con microorganismos para el desarrollo de plantas de cacao (Theobroma cacao L.) en etapa de vivero

La renovación de plantaciones del cultivo de cacao debe hacerse con material vegetal que asegure la supervivencia en el trasplante a campo, por lo cual, es indispensable la producción de plantas en vivero utilizando sustratos que les proporcionen condiciones apropiadas de crecimiento. Por lo anterior, se determinó el efecto de la inoculación microbiana en sustratos utilizados para la producción de plantas de cacao en etapa de vivero para lo cual se utilizaron semillas del clon IMC 67. Se evaluaron los siguientes tratamientos: (T1) testigo absoluto, 1:1 suelo:arena; (T2) bioabono, 2:1:1 suelo:bioabono:arena; (T3) Inoculante comercial mixto, 2:1:1 suelo:lombricompuesto:arena; (T4) rizobacterias cacao, 2:1:1 suelo:lombricompuesto:arena y (T5) testigo químico, 2:1:1 suelo:lombricompuesto:arena + fertilización química. Cada uno de estos cinco tratamientos fue sembrado en 60 bolsas (repeticiones) bajo un diseño experimental completamente al azar. Se determinó la altura de la planta, número de hojas, diámetro del tallo, longitud radical y peso seco foliar y radical, así como las poblaciones de bacterias en agar SRS. El análisis de varianza registró diferencias significativas (P≤0,05) en las plantas de los tratamientos T3 y T4, con respecto a los testigos absoluto y químico en la mayoría de las variables, por lo cual se recomienda la inoculación de estos microorganismos para mejorar el desarrollo vegetal de las plantas de cacao en etapa de vivero y por tanto, su supervivencia en el trasplante a campo. La inoculación microbiana en los sustratos también promovió el incremento de las poblaciones de rizobacterias.Renewal of cocoa crops must be done with strong seedlings to guarantee field transplant survival, which is highly associated with root development in the first months of plant growth. We aimed to evaluate the effect of substrates inoculated with microorganisms in the production of cocoa plants during nursery stage. Seeds of clon IMC-67 were planted in bags. A completely randomized design was used, consisting in five treatments with sixty replicates each, one bag per plot. Treatments were: (T1) absolute control, 1:1 sand:soil; (T2) bioabono, 2:1:1 soil:bioabono:sand; (T3) Commercial mixed inoculant, 2:1:1 soil:vermicompost:sand; (T4) Cocoa rhizobacteria, 2:1:1 soil:vermicompost:sand; and (T5) chemical control, 2:1:1 soil:vermicompost:sand + chemical fertilization. Plant height, root length, number of leaves, stem diameter, shoot and root fresh and dry weight, as well as the microbial populations in SRS agar were measured. The analysis showed significant differences (P≤0.05) between treatments inoculated with microorganisms (T3 and T4) and those that were not inoculated (T1 and T5) in most of the variables. Therefore, the inoculation of these microorganisms is recommended to improve cocoa plant development in nursery stage, and in turn, ensuring the survival after field transplant. Substrate inoculation also promoted the increase of rhizobacteria populations