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Bacterial wilt, caused by Ralstonia solanacearum, is one of the main challenges for sustainable tomato production in the Amazon region. This study evaluated the potential of bacteria isolated from sediments of the Solimões and Negro rivers for the biocontrol of this disease. From 36 bacteria selected through in vitro antibiosis, three promising isolates were identified: Priestia aryabhattai RN 11, Streptomyces sp. RN 24, and Kitasatospora sp. SOL 195, which inhibited the growth of the phytopathogen by 100%, 87.62%, and 100%, respectively. These isolates also demonstrated the ability to produce extracellular enzymes and plant growth-promoting compounds, such as indole-3-acetic acid (IAA), siderophore, and ammonia. In plant assays, during both dry and rainy seasons, P. aryabhattai RN 11 reduced disease incidence by 40% and 90%, respectively, while promoting the growth of infected plants. Streptomyces sp. RN 24 and Kitasatospora sp. SOL 195 exhibited high survival rates (85-90%) and pathogen suppression in the soil (>90%), demonstrating their potential as biocontrol agents. This study highlights the potential of Amazonian bacteria as biocontrol agents against bacterial wilt, contributing to the development of sustainable management strategies for this important disease.

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This brief review aims to draw attention to the biotechnological potential of actinomycetes. Their main uses as sources of antibiotics and in agriculture would be enough not to neglect them; however, as we will see, their biotechnological application is much broader. Far from intending to exhaust this issue, we present a short survey of the research involving actinomycetes and their applications published in the last 23 years. We highlight a perspective for the discovery of new active ingredients or new applications for the known metabolites of these microorganisms that, for approximately 80 years, since the discovery of streptomycin, have been the main source of antibiotics. Based on the collected data, we organize the text to show how the cosmopolitanism of actinomycetes and the evolutionary biotic and abiotic ecological relationships of actinomycetes translate into the expression of metabolites in the environment and the richness of biosynthetic gene clusters, many of which remain silenced in traditional laboratory cultures. We also present the main strategies used in the twenty-first century to promote the expression of these silenced genes and obtain new secondary metabolites from known or new strains. Many of these metabolites have biological activities relevant to medicine, agriculture, and biotechnology industries, including candidates for new drugs or drug models against infectious and non-infectious diseases. Below, we present significant examples of the antimicrobial spectrum of actinomycetes, which is the most commonly investigated and best known, as well as their non-antimicrobial spectrum, which is becoming better known and increasingly explored.

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An environmentally friendly method for the release of cocoa bean shell (CBS) extracts is proposed in this paper. This work aims to investigate the effect of pulsed electric field (PEF) pre-treatment on subsequent solid-liquid extraction (SLE) of metabolites with choline chloride-lactic acid natural deep eutectic solvent (NaDES) and bioactivity of cocoa bean shell (CBS) extract. Two different media for PEF application were evaluated: water and chlorine chloride-lactic acid. Total polyphenols (TPC), total flavonoids (TFC), individual major compounds, and antioxidant and antibacterial activity of CBS extracts were assessed. The performance of PEF-assisted extraction was compared with SLE and ultrasound-assisted extraction (UAE). The proposed method improved the release of TPC up to 45% and TFC up to 48% compared with the conventional extraction. The CBS extract showed medium growth inhibition of Escherichia coli and high growth inhibition of Salmonella sp, Listeria monocytogenes, and Staphylococcus aureus. Thus, an extract with enhanced antioxidant and antibacterial properties was obtained.

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The marine environment is highly diverse, each living creature fighting to establish and proliferate. Among marine organisms, cyanobacteria are astounding secondary metabolite producers representing a wonderful source of biologically active molecules aimed to communicate, defend from predators, or compete. Studies on these molecules' origins and activities have been systematic, although much is still to be discovered. Their broad chemical diversity results from integrating peptide and polyketide synthetases and synthases, along with cascades of biosynthetic transformations resulting in new chemical structures. Cyanobacteria are glycolipid, macrolide, peptide, and polyketide producers, and to date, hundreds of these molecules have been isolated and tested. Many of these compounds have demonstrated important bioactivities such as cytotoxicity, antineoplastic, and antiproliferative activity with potential pharmacological uses. Some are currently under clinical investigation. Additionally, conventional chemotherapeutic treatments include drugs with a well-known range of side effects, making anticancer drug research from new sources, such as marine cyanobacteria, necessary. This review is focused on the anticancer bioactivities of metabolites produced by marine cyanobacteria, emphasizing the identification of each variant of the metabolite family, their chemical structures, and the mechanisms of action underlying their biological and pharmacological activities.

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Agaricus subrufescens has emerged as an important culinary-medicinal mushroom over the last decades. Efforts have been dedicated to upgrade the A. subrufescens productive process via strain selection and cultivation scaling-up. However, little is known on the influence of those variables on the metabolite profiles and nutraceutical properties of this mushroom. In this work, the effects of outdoor versus indoor cultivation on the metabolite profiles of five commercial strains of A. subrufescens were investigated by untargeted metabolomics. UHPLC-MS coupled to multivariate data analysis revealed that the concentration of several metabolites with reported health-related properties as well as related to taste and browning varied significantly between strains and were affected by the cultivation system in a strain-dependent manner. Data suggest that increasing the production scale by means of indoor cultivation may decrease the nutraceutical quality of some A. subrufescens strains while also affecting taste and browning susceptibility to different extents.

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Streptomyces 5.1 is a bacterium isolated from rice soils in the south of the Tolima department (Colombia). This microorganism is characterized by its antagonistic activity against rubber tree phytopathogens like Colletotrichum gloeosporioides, the causal agent of leaf anthracnose. The antifungal activity of this Streptomyces isolate has been associated with secondary metabolites production. However, the identity of those metabolites is unknown because its purification and identification have not been possible through classic chemical studies. Therefore, aiming to contribute in the study of the secondary metabolites produced by 5.1 from a molecular approach, this research seeks to identify -preliminarily- the genomic fingerprint changes associated with the production of antifungal secondary metabolites produced by Streptomyces 5.1 through the evaluation of a mutant library of 5.1 obtained by random mutagenesis using controlled ultraviolet light exposure. The antifungal activity of obtained mutants was evaluated using Colletotrichum gloeosporioides (C1) fungus as a biosensor, isolated by the Biotechnology Institute of Universidad Nacional de Colombia. In this way, the library of mutants of 5.1, initially formed by 300 isolations, was classified into two phenotypic groups of interest: enhanced mutants (1 isolate) and null mutants (11 isolates) of secondary metabolites. The genomic changes in both groups were analyzed by obtaining the genomic profile of the isolates using Repetitive Extragenic Palindromic (Rep-PCR). The obtained profiles evidenced the presence of one additional band in the enhanced mutant, and the absence of a specific band in the non-producing mutants, both in comparison with the original strain. These bands are proposed for a future sequencing study which will define their role in the production process of metabolites with antifungal activity in Streptomyces 5.1.(AU)

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Streptomyces 5.1 is a bacterium isolated from rice soils in the south of the Tolima department (Colombia). This microorganism is characterized by its antagonistic activity against rubber tree phytopathogens like Colletotrichum gloeosporioides, the causal agent of leaf anthracnose. The antifungal activity of this Streptomyces isolate has been associated with secondary metabolites production. However, the identity of those metabolites is unknown because its purification and identification have not been possible through classic chemical studies. Therefore, aiming to contribute in the study of the secondary metabolites produced by 5.1 from a molecular approach, this research seeks to identify -preliminarily- the genomic fingerprint changes associated with the production of antifungal secondary metabolites produced by Streptomyces 5.1 through the evaluation of a mutant library of 5.1 obtained by random mutagenesis using controlled ultraviolet light exposure. The antifungal activity of obtained mutants was evaluated using Colletotrichum gloeosporioides (C1) fungus as a biosensor, isolated by the Biotechnology Institute of Universidad Nacional de Colombia. In this way, the library of mutants of 5.1, initially formed by 300 isolations, was classified into two phenotypic groups of interest: enhanced mutants (1 isolate) and null mutants (11 isolates) of secondary metabolites. The genomic changes in both groups were analyzed by obtaining the genomic profile of the isolates using Repetitive Extragenic Palindromic (Rep-PCR). The obtained profiles evidenced the presence of one additional band in the enhanced mutant, and the absence of a specific band in the non-producing mutants, both in comparison with the original strain. These bands are proposed for a future sequencing study which will define their role in the production process of metabolites with antifungal activity in Streptomyces 5.1.

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The phytochemical study of Laelia marginata (Lindl.) L. O. Williams (Orchidaceae) led to the isolation of a new natural product named crispoic acid (1), together with six other known compounds (2-7). The new natural product was identified as a dimer of eucomic acid and was structurally characterised based upon 1D and 2D NMR and HRMS data. Biological assays with plant crude extract, fractions and isolated compounds were performed against two human cancer cell lines (Hela and Siha), and the tropical parasites Trypanosoma cruzi and Leishmania (Leishmania) amazonensis. The phenantrenoid 9,10-dihydro-4-methoxyphenanthren-2,7-diol 2 was active against Hela and Siha cells (CC50 5.86 ± 0.19 and 20.78 ± 2.72 µg/mL, respectively). Sub-lethal concentrations of the flavone rhamnazin 4 were not able to rescue the viability of the Vero cells infected by Zika virus.

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Secondary metabolites from fungi have become a major source of chemical innovation in programs searching for lead molecules with bioactivities, especially over the last 50 years. In this review, we discuss the fundamental considerations in the discovery of molecules for agricultural and medicinal uses. This group of organisms possesses a strong potential for scientific and industrial communities. Recently, the incorporation of new technologies for the artificial cultivation of fungi and the use of better equipment to isolate and identify active metabolites has allowed the discovery of leading molecules for the design of new and safer drugs and pesticides. The geographical region including the Patagonian Andes mountains harbors a wide diversity of fungi, many of them still unknown and so far associated with Chilean-Argentinian Andean endemic forests. There have been very few chemical studies of the fungi located in this region. However, those few studies have allowed the discovery of new molecules. We argue that the richness of fungal biodiversity in this region offers an interesting source for the discovery of bioactive molecules for the basic and applied sciences.

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This work describes the use of Colubrina greggii as a model to investigate the use of chemometric analysis combined with data from a leishmanicidal bioassay, using Principal Component Analysis (PCA) and Orthogonal Projections to Latent Structures (O-PLS), to detect biologically active natural products in crude extracts from plants having little or no phytochemical information. A first analysis of the HPLC-UV profiles of the extract and its semi-purified fractions using both Principal Component Analysis (PCA) and Orthogonal Partial Least Squares (O-PLS) indicated that the components at tR 48.2, 48.7, 51.8min correlated with the variation in bioactivity. However, a further O-PLS analysis of the HPLC-UV profiles of fractions obtained through a final semi-preparative HPLC purification showed two components at tR 48.7 and 49.5min which correlated with the variation of the bioactivity in a high performance predictive model, with high determination coefficient, high correlation coefficient values (R(2) and Q(2)=0.99) and a low root mean square error (RMSE=0.018). This study demonstrates that the association of chemometric analysis with bioassay results can be an excellent strategy for the detection and isolation of bioactive metabolites from phytochemically unknown plant crude extracts.

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En el presente estudio fueron evaluadas 300 cepas de actinomicetos (140 de origen clínico y 160 del suelo). La producción de sustancias antimicrobianas del total de las cepas de actinomicetos fue evaluada utilizando los siguientes caldos: Bennett (M1), (M2), y el caldo levadura extracto de malta-dextrosa YMD (M3). Se ajustaron las condiciones óptimas de cultivo para lograr altas concentraciones de los metabolitos bioactivos. El proceso de fermentación fue utilizado en tiempos de incubación que variaron entre 5 hasta 10 días. La mayor producción de metabolitos bioactivos se obtuvo cuando se utilizó el medio de producción M2. La actividad antimicrobiana se vio favorecida con la adición de dextrosa, peptona proteosada y extracto de levadura y fosfato de potasio (K2P04), sulfato de magnesio (MgSO4) x 7H2O y carbonato de calcio (CaCO3). Se relacionaron los patrones de crecimiento, la actividad antimicrobiana y la producción de biomasa en las cepas de actinomicetos en los tres medios de cultivo utilizados. Las cepas que presentaron fuerte actividad antimicrobiana contra la mayoría de las bacterias grampositivas, gramnegativas y hongos, fueron seleccionadas para futuros estudios donde se realizará la extracción, purificación y caracterización de los metabolitos bioactivos producidos.

The present study evaluated 300 actinomyces strains (140 from clinical samples and 160 from soil samples). The production of antimicrobial substances by the total actinomyces strains was evaluated using the following broths: Bennet (M1), (M2), and malt-dextrose yeast extract broth YMD (M3). Cultures were adjusted to optimal conditions in order to obtain high bioactive metabolite concentrations. The fermentation process was used with incubation periods which varied between 5 and 10 days. The highest bioactive metabolite production was obtained when the M2 medium was used. Antimicrobial activity was favored with the addition of dextrose, proteose peptone, yeast extract, potassium phosphate (K2PO4), magnesium sulfate (MgSO4) x 7H2O and calcium carbonate (CaCO2). Growth patterns, antimicrobial activity, and biomass production of the actinomyces were related to the three culture media used. The strains which showed strong antimicrobial activity against most gram positive and gram negative bacteria and fungi were selected for future studies where the bioactive metabolites produced will be extracted, purified, and characterized.

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Introduction: the idea to explore at least some of the regions diversity such as the Colombian Orinoco through bioprospecting study of Lacmellea standleyi (Woodson) Monach. arises as a consequence of ignorance of much of the floristic richness in Colombia and the potential relevance of much of this in the nutrition, health and industry. Objective: to evaluate the antioxidant potential, nutritional and phenolic content, antimicrobial activity, and safety degree of aqueous, ethanol, and ethyl acetate extracts of Lacmellea standleyi fruits in three different ripening stages. Methods: the nutritional value was evaluated using standardized methods to full fruit in its three ripening stages. Each of the extracts was chemically characterized by spectrophotometric assays. Antimicrobial activity was measured by the size of inhibition against strains of Staphylococcus aureus, Escherichia coli, and Candida parpsilosis; the acute toxicity of the fruits was measured through in vitro tests using Artemia salina as experimental model. Results: the results show that green fruits are suppliers of antioxidant compounds. Higher levels of nutrients are found in the intermediate state and mature fruit has attractive organoleptic properties and a relatively high nutrient content. Conclusions: the antioxidant capacity of Lacmellea standleyi fruits was evident in the three ripening stages, giving the plant a promising future in the pharmaceutical industry, standing out in this field the fruits in the green stage. Furthermore, the results suggest the application of the intermediate and mature fruits in the finished products development. The safety observed in the plant material warrants its use in human consumption.

Introducción: del desconocimiento de gran parte de la riqueza florística en Colombia y de la importancia que podría tener gran parte de esta en la nutrición, salud e industria, nace la idea de explorar, al menos en parte, la diversidad de regiones como la Orinoquía colombiana a través del estudio de bioprospección de los frutos de Lacmellea standleyi (Woodson) Monach. Objetivo: evaluar el potencial antioxidante, el contenido fenólico y nutricional, la actividad antimicrobiana y el grado de inocuidad de los extractos acuoso, etanólico y de acetato de etilo, de los frutos de Lacmellea standleyi en 3 estadios diferentes de maduración. Métodos: el valor nutricional se evaluó a través de métodos estandarizados, al fruto completo en sus 3 estadios de maduración; cada uno de los extractos se caracterizó químicamente a través de ensayos espectrofotométricos. La actividad antimicrobiana se midió mediante el tamaño del halo de inhibición frente a cepas de Staphylococcus aureus, Escherichia coli y Candida parpsilosis; la toxicidad aguda de los frutos se calculó mediante pruebas in vitro, usando como modelo experimental nauplios de Artemia salina. Resultados: se pudo evidenciar que los frutos verdes aportan compuestos antioxidantes. En el estado intermedio se encuentran los niveles más altos de nutrientes y el fruto maduro ostenta atractivas propiedades organolépticas y un contenido relativamente alto de nutrientes. Conclusiones: la capacidad antioxidante de los frutos de Lacmellea standleyi resultó evidente en los 3 estadios de maduración. Esto otorga al vegetal un futuro promisorio en la industria farmacológica, sobresaliendo en este campo los frutos en el estadio verde. Además, los resultados permiten sugerir la aplicación de los frutos en estado intermedio y maduro en la elaboración de productos alimenticios terminados. La inocuidad observada en el material vegetal garantizaría su uso en el consumo humano.