Ceramidas y terpenoides desde Russula austrodelica Singer

Una mezcla de ceramidas y de terpenos conocidos, se obtuvo de los cuerpos fructíferos de Russula austrodelica. Las estructuras fueron determinadas a partir  de evidencias químicas y espectroscópicas. R. austrodelica es un hongo micorrícico que crecen en los bosques de Nothophagus del sur de Chile. Este es el  primer informe del aislamiento de ceramidas en hongos chilenos

Actividad Insecticida de Rhamnaceas Chilenas: Talguenea quinquenervis (Gill. et Hook)

La actividad insecticida de diferentes extractos obtenidos desde la parte aérea de Talguenea quinquenervis (Gill. ex Hook) se evaluó utilizando bioensayos con larvas de Drosophila melanogaster. Todos los extractos ensayados presentan actividad insecticida, siendo las mas activas aquellas fracciones que contienen alcaloides. Desde la fracción activa fue posible aislar e identificar tres conocidos alcaloides, coclaurina, armepavina y N-metilcoclaurina

Efectos de la solubilidad sobre la actividad antibacteriana de quitooligosacáridos modificados químicamente de origen fúngico

Quitina y quitosano son una clase de metabolitos que producen algunas especies de hongos que están asociados con plantas medicinales y comerciales, esto es por ejemplo en Mucor sp., con un amplio número de actividades biológicas, siendo la antibacteriana y antifúngica unas de las más importantes. En nuestro programa de investigación de biopesticidas y compuestos naturales, estamos estudiando quitosano obtenido de el medio de cultivo del hongo Mucor ruoxii. Quitooligosacáridos fueron preparados por hidrólisis parcial ácida de quitosano nativo y un derivado aminoglicosilado fue obtenido por aminación reductiva del quitooligosacárido. Las solubilidades de estos compuestos fueron medidas a diferentes pHs y su actividad antibacteriana frente a Escherichia coli (gram- negative) and Staphylococcus aureus (gram-positive). Quitosano y los derivados testeados exhiben una buena actividad antibacteriana frente a S. aureus

Antarctic Streptomyces fildesensis So13.3 strain as a promising source for antimicrobials discovery

Antarctic have been suggested as an attractive source for antibiotics discovery and members of Streptomyces genus have historically been studied as natural producers of antimicrobial metabolites. Nonetheless, our knowledge on antibiotic-producing Streptomyces from Antarctic is very limited. In this study, the antimicrobial activity of organic extracts from Antarctic Streptomyces strains was evaluated by disk diffusion assays and minimum inhibitory concentration. The strain Streptomyces sp. So13.3 showed the greatest antibiotic activity (MIC = 15.6 μg/mL) against Gram-positive bacteria and growth reduction of Gram‒negative pathogens. The bioactive fraction in the crude extract was revealed by TLC‒bioautography at Rf = 0.78 with molecular weight between 148 and 624 m/z detected by LC-ESI-MS/MS. The strain So13.3 was taxonomically affiliated as Streptomyces fildesensis. Whole genome sequencing and analysis suggested a 9.47 Mb genome size with 42 predicted biosynthetic gene clusters (BGCs) and 56 putative clusters representing a 22% of total genome content. Interestingly, a large number of them (11 of 42 BGCs and 40 of 56 putative BGCs), did not show similarities with other known BGCs. Our results highlight the potential of the Antarctic Streptomyces strains as a promising source of novel antimicrobials, particularly the strain Streptomyces fildesensis So13.3, which first draft genome is reported in this work

Biosurfactant Production by <i>Bacillus amyloliquefaciens</i> C11 and <i>Streptomyces lavendulae</i> C27 Isolated from a Biopurification System for Environmental Applications

Biosurfactant-producing bacteria can be found in contaminated environments such as biopurification systems (BPS) for pesticide treatments. A total of 18 isolates were screened to determine their ability to produce extracellular biosurfactants, using olive oil as the main carbon source. Out of the eighteen isolates, two strains (C11 and C27) were selected for biosurfactant production. The emulsification activities of the C11 and C27 strains using sunflower oil was 58.4 and 53.7%, respectively, and 46.6 and 48.0% using olive oil. Using molecular techniques and MALDI-TOF, the strains were identified as Bacillus amyloliquefaciens (C11) and Streptomyces lavendulae (C27). The submerged cultivation of the two selected strains was carried out in a 1 L stirred-tank bioreactor. The maximum biosurfactant production, indicated by the lowest surface tension measurement, was similar (46 and 45 mN/m) for both strains, independent of the fact that the biomass of the B. amyloliquefaciens C11 strain was 50% lower than the biomass of the S. lavendulae C27 strain. The partially purified biosurfactants produced by B. amyloliquefaciens C11 and S. lavendulae C27 were characterized as a lipopeptide and a glycolipid, respectively. These outcomes highlight the potential of the selected biosurfactant-producing microorganisms for improving pesticides’ bioavailability and therefore the degradational efficacy of BPS

Evaluación de la temperatura corporal en sistemas de producción ovina en el Centro de Formación Agroindustrial

El objetivo de este estudio es evaluar y comparar la temperatura corporal de los ovinos en dos hábitat diferentes: en ambiente con arreglo silvopastoril con árboles dispersos (CS) y en pradera convencional (SS), establecidos en el Centro de Formación Agroindustrial. Se organizaron dos grupos de ovinos, cada uno con un ejemplar de la raza Santa Inés y otro de la raza Katahdin. Las variables registradas para medir las condiciones ambientales fueron la temperatura atmosférica (TaºC) y la humedad relativa (% HR), y en los ovinos la temperatura corporal vía rectal (TrºC). Los datos fueron analizados de manera descriptiva considerando la relación entre los dos ambientes, encontrando que los ovinos en condiciones SS alcanzaron la temperatura corporal interna más alta (39.53ºC), afectada directamente por la temperatura ambiental (33.38ºC), pero al mismo tiempo presentaron autorregulación térmica, como se puede evidenciar al comparar con los valores de CS. El estudio concluye que la presencia de sombra dentro de los sistemas productivos en ovinos mejora las respuestas del confort animal en la temperatura corporal

Pesticide-tolerant bacteria isolated from a biopurification system to remove commonly used pesticides to protect water resources.

In this study, we selected and characterized different pesticide-tolerant bacteria isolated from a biomixture of a biopurification system that had received continuous applications of a pesticides mixture. The amplicon analysis of biomixture reported that the phyla Proteobacteria, Firmicutes, Bacteroidetes and Actinobacteria were predominant. Six strains grew in the presence of chlorpyrifos and iprodione. Biochemical characterization showed that all isolates were positive for esterase, acid phosphatase, among others, and they were identified as Pseudomonas, Rhodococcus and Achromobacter based on molecular and proteomic analysis. Bacterial growth decreased as both pesticide concentrations increased from 10 to 100 mg L-1 in liquid culture. The Achromobacter sp. strain C1 showed the best chlorpyrifos removal rate of 0.072-0.147 d-1 a half-life of 4.7-9.7 d and a maximum metabolite concentration of 2.10 mg L-1 at 120 h. On the other hand, Pseudomonas sp. strain C9 showed the highest iprodione removal rate of 0.100-0.193 d-1 a half-life of 4-7 d and maximum metabolite concentration of 0.95 mg L-1 at 48 h. The Achromobacter and Pseudomonas strains showed a good potential as chlorpyrifos and iprodione-degrading bacteria

The insecticidal, molting disruption and insect growth inhibitory activity of extracts from Condalia microphylla Cav. (Rhamnaceae)

Extracts obtained from a common shrub that occurs as part of vegetative species growing on arid lands of North-Central Chile and adjacent central Argentina known as “piquilin” Condalia microphylla (Rhamnaceae) showed insect growth inhibitory activity against the fall armyworm Spodoptera frugiperda, yellow meal worm Tenebrio molitor and fruit fly Drosophila melanogaster larvae in artificial diet feeding assays. The effects of these extracts on mortality, antifeedancy and growth inhibition were examined. The phytochemical profile of the most active extract was examined with conventional chromatographic and spectroscopic procedures. This n-hexane extract showed a high percentage of hentriacontane and triacontane. The observed mortality strongly correlates with the contents of these long-chain n-alkanes compounds, the LD50 for n-hexane, ethyl acetate and methanol extracts against S. frugiperda, were 3.89, 9.4, and 9.7 ppm; against T. molitor 5.2, 14.2, and 20.4 ppm, and against D. melanogaster 3.23, 7.65 and 17.9 ppm, respectively.Fil: Cespedes, Carlos L.. Universidad del Bio Bio; ChileFil: Molina, Sofia C.. Universidad del Bio Bio; ChileFil: Muñoz, Evelyn. Universidad del Bio Bio; ChileFil: Lamilla, Claudio. Universidad del Bio Bio; ChileFil: Alarcon, Julio. Universidad del Bio Bio; ChileFil: Palacios, Sara Maria. Universidad Catolica de Córdoba. Facultad de Ciencias Químicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carpinella, Maria Cecilia. Universidad Catolica de Córdoba. Facultad de Ciencias Químicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Avila, José G.. Universidad Nacional Autonoma de Mexico. Facultad de Estudios Superiores de Iztacala; Méxic

<i>Streptomyces luridus</i> So3.2 from Antarctic soil as a novel producer of compounds with bioemulsification potential

<div><p>The present study aimed to identify novel microbial producers of bioemulsificant compounds from Antarctic soils. Fifty-nine microbial strains were isolated from five different locations at South Shetland Islands, Antarctica, and screened for biosurfactant production by β-hemolytic activity. Strain So 3.2 was determined as bioemulsifier-producer and identified by phenotypic and molecular characterization as <i>Streptomyces luridus</i>. Emulsification activity, oil displacement method and drop-collapsing test were performed to evaluate the biosurfactant activity with different oils and hydrocarbons using two different culture media (Luria Bertani and Bushnell Haas in the presence of different carbon sources: glucose, glycerol, olive oil and n-Hexadecane). Cell free supernatant of Bushnell Haas culture supplemented with n-Hexadecane showed the best results for all tests. Emulsification of hydrocarbons exceeded 60%, reaching up to 90% on oil with high API grade, while displacement tests ranged from 8 cm to 4 cm in diameter according the culture media and tested oils. Our results revealed that <i>Streptomyces luridus</i> So3.2 is able to produce bioemulsifiers capable of emulsifying hydrocarbons and oils, which could be used in different biotechnological applications, particularly for bioremediation of environments contaminated by oil leaks.</p></div

Evaluation of the surface-active biomolecules production by <i>Streptomyces luridus</i> So3.2 on different culture media and carbon sources.

<p>Evaluation of the surface-active biomolecules production by <i>Streptomyces luridus</i> So3.2 on different culture media and carbon sources.</p