Aplicación de cepas de Microbacterium spp. productoras de compuestos orgánicos volátiles (COVs) como agentes biopesticidas y fitoestimulantes en semilleros de lechuga

RESUMEN: El uso abusivo de fitosanitarios de naturaleza química para el control de enfermedades vegetales ha ocasionado la pérdida de biodiversidad en el suelo, tanto por los daños sanitarios y ambientales que ocasionan, como por la aparición de resistencias a estos plaguicidas. Todo esto ha derivado en una importante demanda de medidas sustitutivas o complementarias, ambientalmente sostenibles, que sean capaces de controlar de forma eficiente y segura los patógenos vegetales. En este sentido, durante las últimas décadas, el control biológico y la búsqueda de nuevos agentes bioplaguicidas han supuesto un campo de estudio de especial interés dentro de la Agrobiotecnología. En este estudio, se trabajó con una colección de 29 cepas identificadas como Microbacterium spp., que pertenecían a la colección privada del grupo de investigación BIO-175 de la Universidad de Almería. El objetivo del trabajo fue determinar si, mediante la producción de compuestos orgánicos volátiles (COVs), estos organismos podrían actuar como agentes antagonistas del hongo fitopatógeno Botrytis cinerea (moho gris) y, al mismo tiempo, como promotores del crecimiento en plántulas de lechuga tras ser aplicadas mediante la técnica de priming. Aquellas cepas que mostraron resultados prometedores in vitro, con respecto a la capacidad antagonista así como fitoestimulante, se seleccionaron para la realización de ensayos posteriores in vivo en los que ambos aspectos fueron evaluados. A partir de un ensayo preliminar de antagonismo in vitro, se seleccionaron 5 cepas de Microbacterium spp., capaces de inhibir en más de un 30% el crecimiento del micelio de B. cinerea. Sólo 3 de estas 5 cepas mostraron resultados positivos en el ensayo de promoción de la germinación in vitro, obteniendo datos de incremento del peso radicular en torno al 45%, con respecto a los controles no tratados mediante priming. Por último, estas tres cepas fueron ensayadas in vivo, provocando efectos beneficiosos con respecto al desarrollo aéreo y radicular de plántulas de lechuga, así como paliando los daños provocados por Botrytis cinerea. ABSTRACT: The abusive use of chemical pesticides for the control of plant diseases has led to the loss of soil biodiversity, both due to the sanitary and environmental damage they cause, as well as the appearance of resistance by pathogens. This effect has resulted in a significant demand for other environmentally sustainable alternatives that serve to control plant pathogens safely and efficiently. In this sense, during the last decades, the search for new biopesticides has been a field of special interest within Agrobiotechnology. In this research work, a collection of 29 strains included in the genus Microbacterium belonging to the private collection of the research group BIO-175 of the University of Almería, was studied. The objective of this work was to determine if the production of volatile organic compounds (VOCs) could act antagonistically against the fungus Botrytis cinerea, which causes gray mold disease and, at the same time, promote the development of growth in lettuce seedlings. Strains showing positive results in vitro, both for the biopesticide effect and for growth promotion, were selected for in vivo tests, in which both effects were evaluated simultaneously. In the first trial, 5 strains were selected, which were able to inhibit the growth of the fungus to a degree greater than 30%. Only 3 of these 5 strains showed positive results in the in vitro germination promotion test, increasing root weight around 45%. Finally, these 3 strains were tested in vivo, showing a palliative effect of Botrytis cinerea and promoting the development of lettuce seedlings at aerial and root levels

Further Advances in Atrial Fibrillation Research: A Metabolomic Perspective

Atrial fibrillation involves an important type of heart arrhythmia caused by a lack of control in the electrical signals that arrive in the heart, produce an irregular auricular contraction, and induce blood clotting, which finally can lead to stroke. Atrial fibrillation presents some specific characteristics, but it has been treated and prevented using conventional methods similar to those applied to other cardiovascular diseases. However, due to the influence of this pathology on the mortality caused by cerebrovascular accidents, further studies on the molecular mechanism of atrial fibrillation are required. Our aim here is provide a compressive review of the use of metabolomics on this condition, from the study of the metabolic profile of plasma to the development of animal models. In summary, most of the reported studies highlighted alterations in the energetic pathways related to the development of the condition

Repurposing of the tamoxifen metabolites in combination with tigecycline against Gram-negative bacteria

Motivation: Emerging of multidrug-resistant (MDR) bacteria represent a matter of grave urgency and a problem for public health. Due to the emergence of resistance new strategic antimicrobial therapeutic approaches are proposed, such as drug repurposing. Tamoxifen was previously reported to present efficacy against MDR Acinetobacter baumannii and Escherichia coli [1]. The objetive of this project was to study in vitro the activity of the three major metabolites of tamoxifen (MET): N-desmethyltamoxifen, 4-hydroxytamoxifen, and endoxifen, in combination with tigecycline against colistin-susceptible (COL-S) and colistin-resistant (COL-R) A. baumannii and E. coli. Methods: A colection of Gram-negative bacteria [8 COL-R and 1 COL-S A. baumannii, 17 COL-R and 1 COL-S E. coli] was used [2]. All strains were grown in Mueller-Hinton Broth (MHB) at 37ºC. Minimal Inhibitory Concentration (MIC) was determined for all strains by using microdilution assay. In order to determine the synergy between a mix of the three MET and tigecycline checkerboard and time-kill curves assays were performed. Results: Tigecycline MIC range was 4-8 mg/L for all COL-R A. baumannii strains, 0.5 mg/L for COL-S A. baumannii strain and 0.125-1 mg/L for both COL-R and COL-S E. coli strains. Checkerboard analyses showed partial synergism for combination tigecycline and MET against COL-R ans COL-S A. baumannii and E. coli strains. Time-kill curves confirmed synergetic effect and inhibited partially and completely the regrowth of COL-R E. coli and A. baumannii strains, respectively. Conclusions: Tamoxifen metabolites in combination with tigecycline showed in vitro synergetic effect against COL-R A. baumannii and E. coli strains, representing a potential new alternative for treatment of infections caused by MDR A. baumannii and E. coli

Evaluation of Nutritional Practices in the Critical Care patient (The ENPIC study) : Does nutrition really affect ICU mortality?

The importance of artificial nutritional therapy is underrecognized, typically being considered an adjunctive rather than a primary therapy. We aimed to evaluate the influence of nutritional therapy on mortality in critically ill patients. Methods: This multicenter prospective observational study included adult patients needing artificial nutritional therapy for >48 h if they stayed in one of 38 participating intensive care units for ≥72 h between April and July 2018. Demographic data, comorbidities, diagnoses, nutritional status and therapy (type and details for ≤14 days), and outcomes were registered in a database. Confounders such as disease severity, patient type (e.g., medical, surgical or trauma), and type and duration of nutritional therapy were also included in a multivariate analysis, and hazard ratios (HRs) and 95% confidence intervals (95%CIs) were reported. We included 639 patients among whom 448 (70.1%) and 191 (29.9%) received enteral and parenteral nutrition, respectively. Mortality was 25.6%, with non-survivors having the following characteristics: older age; more comorbidities; higher Sequential Organ Failure Assessment (SOFA) scores (6.6 ± 3.3 vs 8.4 ± 3.7; P < 0.001); greater nutritional risk (Nutrition Risk in the Critically Ill [NUTRIC] score: 3.8 ± 2.1 vs 5.2 ± 1.7; P < 0.001); more vasopressor requirements (70.4% vs 83.5%; P=0.001); and more renal replacement therapy (12.2% vs 23.2%; P=0.001). Multivariate analysis showed that older age (HR: 1.023; 95% CI: 1.008-1.038; P=0.003), higher SOFA score (HR: 1.096; 95% CI: 1.036-1.160; P=0.001), higher NUTRIC score (HR: 1.136; 95% CI: 1.025-1.259; P=0.015), requiring parenteral nutrition after starting enteral nutrition (HR: 2.368; 95% CI: 1.168-4.798; P=0.017), and a higher mean Kcal/Kg/day intake (HR: 1.057; 95% CI: 1.015-1.101; P=0.008) were associated with mortality. By contrast, a higher mean protein intake protected against mortality (HR: 0.507; 95% CI: 0.263-0.977; P=0.042). Old age, higher organ failure scores, and greater nutritional risk appear to be associated with higher mortality. Patients who need parenteral nutrition after starting enteral nutrition may represent a high-risk subgroup for mortality due to illness severity and problems receiving appropriate nutritional therapy. Mean calorie and protein delivery also appeared to influence outcomes. ClinicaTrials.gov NCT: 03634943