Actividad in vitro of 5-(2, 4-dimetilbencil) pirrolidin-2-uno extraído de Streptomyces VITSVK5 sp. marino frente a patógenos fúngicos y bacterianos humanos / In vitro activity of 5-(2, 4-dimethylbenzyl) pyrrolidin-2-one extracted from marine Streptomyces VITSVK5 spp. against fungal and bacterial human pathogens

Antecedentes: El cribado farmacológico y el uso de productos naturales para el tratamiento de las enfermedades humanas tiene un largo historial que comienza en la medicina tradicional y se extiende hasta los fármacos modernos. La mayoría de los fármacos modernos proceden principalmente de productos naturales. Objetivo. El objetivo del presente estudio fue valorar la actividad inhibidora of 5-(2,4-dimetilbencil) pirrolidin-2-uno (DMBPO) extraído de Streptomyces VITSVK5 sp. marino aislado de muestras de sedimento recolectadas en la costa de Marakkanam de la bahía de Bengala, India. Métodos. El compuesto principal se aisló mediante extracción bioactiva guiada y se purificó mediante cromatografía de columna de gel de sílice. La dilucidación estructural del compuesto principal se efectuó utilizando datos espectrales de las técnicas UV, FT-IR, 1H NMR, 13C NMR, DEPT y HR-MS. Resultados. El cribado sistemático de los aislamientos en busca de actividad antimicrobiana dio lugar a la identificación de una cepa potencial, Streptomyces VITSVK5 sp. (GQ848482). Con la extracción bioactiva guiada se obtuvo un compuesto DMBPO y su actividad inhibidora se examinó frente a cepas bacterianas y fúngicas seleccionadas. DMBPO mostró una actividad máxima frente a Escherichia coli con un valor de la concentración inhibitoria mínima (CIM) de 187mg/ml, seguida de Klebsiella pneumoniae (CIM de 220mg/ml y zona de inhibición de 10,3mm), Staphylococcus aureus (CIM>1.000mg/ml y zona de inhibición de 4,4mm) y Bacillus subtilis (CIM de 850mg/ml y zona de inhibición de 2,6mm). Además, se puso de relieve que DMBPO también fue un inhibidor potente de los patógenos fúngicos oportunistas. Se demostró una actividad máxima frente a Aspergillus niger con un valor de CIM de 1mg/ml y una zona de inhibición de 28mm. Conclusión. El resultado del presente estudio indica que DMBPO posee actividad antibiótica frente a patógenos bacterianos y fúngicos seleccionados y exhibió una mejor actividad frente a hongos que bacterias(AU)

Background. Pharmacological screening and usage of natural products for the treatment of human diseases has had a long history from traditional medicine to modern drugs. The majority of modern drugs are reported to be mostly from natural products. Objective. The aim of the present study was to evaluate the inhibitory activity of 5-(2,4-dimethylbenzyl) pyrrolidin-2-one (DMBPO) extracted from marine Streptomyces VITSVK5 spp. isolated from sediment samples collected at Marakkanam coast of Bay of Bengal, India. Methods. The lead compound was isolated by bioactive guided extraction and purified by silica gel column chromatography. Structural elucidation of the lead compound was carried out by using UV, FT-IR, 1H NMR, 13C NMR, DEPT and HR-MS spectral data. Results. Systematic screening of isolates for antimicrobial activity lead to identification of a potential strain, Streptomyces VITSVK5 spp. (GQ848482). Bioactivity guided extraction yielded a compound DMBPO and its inhibitory activity was tested against selected bacterial and fungal strains. DMBPO showed maximal activity against Escherichia coli with a MIC value of 187mg/ml, followed by Klebsiella pneumoniae (MIC of 220mg/ml and 10.3mm zone of inhibition), Staphylococcus aureus (MIC of >1000mg/ml and 4.4mm zone of inhibition) and Bacillus subtilis (MIC of 850m/ml and 2.6mm zone of inhibition). Furthermore, DMBPO was found to be a potent inhibitor of opportunistic fungal pathogens too. It showed a maximum activity against Aspergillus niger with a MIC value of 1mg/ml and 28mm zone of inhibition. Conclusion. The result of this study indicates that DMBPO possess antibiotic activity to selected bacterial and fungal pathogens and exhibited better activity against fungi than bacteria(AU)

Antimycobacterial natural products – an opportunity for the Colombian biodiversity

Se ha estimado que un tercio de la población mundial está infectado con el bacilo tuberculoso. Aunque un pequeño por centaje de los individuos afectados desarrollará clínicamente la enfermedad, cada año esta ocasiona aproximadamente ocho millones de nuevos casos y dos millones de muertes. Mycobacterium tuberculosis es el agente infeccioso que produce la mayor mortalidad humana, comparado con cualquier otra especie microbiana. Los objetivos de los distintos programas para el control de la tuberculosis son la cura y diagnóstico de la infección activa, la prevención de recaídas, la reducción de transmisión y evitar la aparición de la resistencia a los medicamentos. Por más de 50 años, los productos naturales han sido útiles en combatir bacterias y hongos patógenos. Durante el siglo 20 los metabolitos secundarios provenientes de plantas y microorganismos revolucionaron la medicina ayudando a controlar el dolor y el sufrimiento en miles de personas. Colombia es un país megabiodiverso, con un enorme potencial para ofrecer moléculas líderes, para el desarrollo de nuevos fármacos antituberculosos. El principal objetivo de este artículo es dar a conocer un estado del arte en la investigación de productos naturales antimicobacterianos en Colombia comparando con otros programas de bioprospección existentes en el mundo y así poder valorar las enormes ventajas que puede tener este recurso inexplorado(AU)

It is estimated that one-third part of the world population is infected with the tubercle bacillus. While only a small percentage of infected individuals will develop clinical tuberculosis, each year there are approximately eight million new cases and two million deaths. Mycobacterium tuberculosis is thus responsible for more human mortality than any other single microbial species. The goals of tuberculosis control are focused to cure active disease, prevent relapse, reduce transmission and avert the emergence of drug-resistance. For over 50 years, natural products have served us well on combating infectious bacteria and fungi. During the 20th century, microbial and plant secondary metabolites have helped to double our life span, reduced pain and suffering, and revolutionized medicine. Colombia is a megadiverse country with enormous potential to offer leads for new antimycobacterial drugs. The principal aim of this article is to show a state of the art on antimycobacterial natural products research in Colombia compared to the rest of the world, in order to develop programs for bioprospecting with a view to determining the biological activity for pharmaceutical and industrial application of natural products in our country(AU)

Bacteria-induced natural product formation in the fungus Aspergillus nidulans requires Saga/Ada-mediated histone acetylation.

Sequence analyses of fungal genomes have revealed that the potential of fungi to produce secondary metabolites is greatly underestimated. In fact, most gene clusters coding for the biosynthesis of antibiotics, toxins, or pigments are silent under standard laboratory conditions. Hence, it is one of the major challenges in microbiology to uncover the mechanisms required for pathway activation. Recently, we discovered that intimate physical interaction of the important model fungus Aspergillus nidulans with the soil-dwelling bacterium Streptomyces rapamycinicus specifically activated silent fungal secondary metabolism genes, resulting in the production of the archetypal polyketide orsellinic acid and its derivatives. Here, we report that the streptomycete triggers modification of fungal histones. Deletion analysis of 36 of 40 acetyltransferases, including histone acetyltransferases (HATs) of A. nidulans, demonstrated that the Saga/Ada complex containing the HAT GcnE and the AdaB protein is required for induction of the orsellinic acid gene cluster by the bacterium. We also showed that Saga/Ada plays a major role for specific induction of other biosynthesis gene clusters, such as sterigmatocystin, terrequinone, and penicillin. Chromatin immunoprecipitation showed that the Saga/Ada-dependent increase of histone 3 acetylation at lysine 9 and 14 occurs during interaction of fungus and bacterium. Furthermore, the production of secondary metabolites in A. nidulans is accompanied by a global increase in H3K14 acetylation. Increased H3K9 acetylation, however, was only found within gene clusters. This report provides previously undescribed evidence of Saga/Ada dependent histone acetylation triggered by prokaryotes.

Regioselective reactions for programmable resveratrol oligomer synthesis.

Although much attention has been devoted to resveratrol, a unique polyphenol produced by plants and credited as potentially being responsible for the 'French paradox'--the observation that French people have a relatively low incidence of coronary heart disease, even though their diet is high in saturated fats--the oligomers of resveratrol have been largely ignored despite their high biological activity. Challenges in achieving their isolation in sufficient quantity from natural sources, coupled with an inability to prepare them easily synthetically, are seen as the main obstacles. Here we report a programmable, controlled and potentially scalable synthesis of the resveratrol family via a three-stage design. The synthetic approach requires strategy- and reagent-guided chemical functionalizations to differentiate two distinct cores possessing multiple sites with the same or similar reactivity, ultimately leading to five higher-order natural products. This work demonstrates that challenging, positionally selective functionalizations of complex materials are possible where biosynthetic studies have indicated otherwise, it provides materials and tools with which to unlock the full biochemical potential of this family of natural products, and it affords an intellectual framework within which other oligomeric families could potentially be accessed.

Influence of inoculum density and aeration volume on biomass and bioactive compound production in bulb-type bubble bioreactor cultures of Eleutherococcus koreanum Nakai.

This study deals with the effects of initial inoculum density and aeration volume on biomass and bioactive compound production in adventitious roots of Eleutherococcus koreanum Nakai in bulb-type bubble bioreactors (3-L capacity). While the fresh and dry weights of the roots increased with increasing inoculum density, the highest percentage dry weight and accumulation of total target compounds (eleutheroside B and E, chlorogenic acid, total phenolics, and flavonoids) were noted at an inoculum density of 5.0 g L(-1). Poor aeration volume (0.05 vvm) stunted root growth, and high aeration volume (0.4 vvm) caused physiological disorders. Moreover, an inoculum density of 5.0 g L(-1) and an aeration volume of 0.1 vvm resulted in the highest concentration of total target compounds and least root death. Such optimization of culture conditions will be beneficial for the large-scale production of E. koreanum biomass and bioactive compounds.

Convergent strategies in biosynthesis.

This review article focuses on how nature sometimes solves the same problem in the biosynthesis of small molecules but using very different approaches. Four examples, involving isopentenyl diphosphate, menaquinone, lysine, and aromatic polyketides, are highlighted that represent different strategies in convergent metabolism.

Cryptic Aspergillus nidulans antimicrobials.

Secondary metabolite (SM) production by fungi is hypothesized to provide some fitness attribute for the producing organisms. However, most SM clusters are "silent" when fungi are grown in traditional laboratory settings, and it is difficult to ascertain any function or activity of these SM cluster products. Recently, the creation of a chromatin remodeling mutant in Aspergillus nidulans induced activation of several cryptic SM gene clusters. Systematic testing of nine purified metabolites from this mutant identified an emodin derivate with efficacy against both human fungal pathogens (inhibiting both spore germination and hyphal growth) and several bacteria. The ability of catalase to diminish this antimicrobial activity implicates reactive oxygen species generation, specifically, the generation of hydrogen peroxide, as the mechanism of emodin hydroxyl activity.

Underestimated biodiversity as a major explanation for the perceived rich secondary metabolite capacity of the cyanobacterial genus Lyngbya.

Marine cyanobacteria are prolific producers of bioactive secondary metabolites responsible for harmful algal blooms as well as rich sources of promising biomedical lead compounds. The current study focused on obtaining a clearer understanding of the remarkable chemical richness of the cyanobacterial genus Lyngbya. Specimens of Lyngbya from various environmental habitats around Curaçao were analysed for their capacity to produce secondary metabolites by genetic screening of their biosynthetic pathways. The presence of biosynthetic pathways was compared with the production of corresponding metabolites by LC-ESI-MS² and MALDI-TOF-MS. The comparison of biosynthetic capacity and actual metabolite production revealed no evidence of genetic silencing in response to environmental conditions. On a cellular level, the metabolic origin of the detected metabolites was pinpointed to the cyanobacteria, rather than the sheath-associated heterotrophic bacteria, by MALDI-TOF-MS and multiple displacement amplification of single cells. Finally, the traditional morphology-based taxonomic identifications of these Lyngbya populations were combined with their phylogenetic relationships. As a result, polyphyly of morphologically similar cyanobacteria was identified as the major explanation for the perceived chemical richness of the genus Lyngbya, a result which further underscores the need to revise the taxonomy of this group of biomedically important cyanobacteria.

Linking chemistry and genetics in the growing cyanobactin natural products family.

Ribosomal peptide natural products are ubiquitous, yet relatively few tools exist to predict structures and clone new pathways. Cyanobactin ribosomal peptides are found in ~30% of all cyanobacteria, but the connection between gene sequence and structure was not defined, limiting the rapid identification of new compounds and pathways. Here, we report discovery of four orphan cyanobactin gene clusters by genome mining and an additional pathway by targeted cloning, which represented a tyrosine O-prenylating biosynthetic pathway. Genome mining enabled discovery of five cyanobactins, including peptide natural products from Spirulina supplements. A phylogenetic model defined four cyanobactin genotypes, which explain the synthesis of multiple cyanobactin structural classes and help direct pathway cloning and structure prediction efforts. These strategies were applied to DNA isolated from a mixed cyanobacterial bloom containing cyanobactins.

Significant natural product biosynthetic potential of actinorhizal symbionts of the genus frankia, as revealed by comparative genomic and proteomic analyses.

Bacteria of the genus Frankia are mycelium-forming actinomycetes that are found as nitrogen-fixing facultative symbionts of actinorhizal plants. Although soil-dwelling actinomycetes are well-known producers of bioactive compounds, the genus Frankia has largely gone uninvestigated for this potential. Bioinformatic analysis of the genome sequences of Frankia strains ACN14a, CcI3, and EAN1pec revealed an unexpected number of secondary metabolic biosynthesis gene clusters. Our analysis led to the identification of at least 65 biosynthetic gene clusters, the vast majority of which appear to be unique and for which products have not been observed or characterized. More than 25 secondary metabolite structures or structure fragments were predicted, and these are expected to include cyclic peptides, siderophores, pigments, signaling molecules, and specialized lipids. Outside the hopanoid gene locus, no cluster could be convincingly demonstrated to be responsible for the few secondary metabolites previously isolated from other Frankia strains. Few clusters were shared among the three species, demonstrating species-specific biosynthetic diversity. Proteomic analysis of Frankia sp. strains CcI3 and EAN1pec showed that significant and diverse secondary metabolic activity was expressed in laboratory cultures. In addition, several prominent signals in the mass range of peptide natural products were observed in Frankia sp. CcI3 by intact-cell matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS). This work supports the value of bioinformatic investigation in natural products biosynthesis using genomic information and presents a clear roadmap for natural products discovery in the Frankia genus.

Temporal dynamics of natural product biosynthesis in marine cyanobacteria.

Sessile marine organisms are prolific sources of biologically active natural products. However, these compounds are often found in highly variable amounts, with the abiotic and biotic factors governing their production remaining poorly understood. We present an approach that permits monitoring of in vivo natural product production and turnover using mass spectrometry and stable isotope ((15)N) feeding with small cultures of various marine strains of the natural product-rich cyanobacterial genus Lyngbya. This temporal comparison of the amount of in vivo (15)N labeling of nitrogen-containing metabolites represents a direct way to discover and evaluate factors influencing natural product biosynthesis, as well as the timing of specific steps in metabolite assembly, and is a strong complement to more traditional in vitro studies. Relative quantification of (15)N labeling allowed the concurrent measurement of turnover rates of multiple natural products from small amounts of biomass. This technique also afforded the production of the neurotoxic jamaicamides to be more carefully studied, including an assessment of how jamaicamide turnover compares with filament growth rate and primary metabolism and provided new insights into the biosynthetic timing of jamaicamide A bromination. This approach should be valuable in determining how environmental factors affect secondary metabolite production, ultimately yielding insight into the energetic balance among growth, primary production, and secondary metabolism, and thus aid in the development of methods to improve compound yields for biomedical or biotechnological applications.

Emerging antibody products and Nicotiana manufacturing.

Antibody based products are not widely available to address multiple global health challenges due to high costs, limited manufacturing capacity, and long manufacturing lead times. Nicotiana-based manufacturing of antibody products may now begin to address these challenges as a result of revolutionary advances in transient expression and altered glycosylation pathways. This review provides examples of emerging antibody-based products (mucosal and systemic) that could be competitive and commercially viable when the attributes of Nicotiana-based manufacturing (large scale, versatile, rapid, low cost) are utilized.

Natural product biosynthesis inspired concise and stereoselective synthesis of benzopyrones and related scaffolds.

A natural product biosynthesis-inspired strategy to explore biologically relevant chemical space is presented. A phosphine-catalyzed cascade and stereoselective annulation provides a common tricyclic benzopyrone intermediate that was efficiently transformed into diverse and related naturally occurring scaffolds.

Thiazole/oxazole-modified microcins: complex natural products from ribosomal templates.

With billions of years of evolution under its belt, Nature has been expanding and optimizing its biosynthetic capabilities. Chemically complex secondary metabolites continue to challenge and inspire today's most talented synthetic chemists. A brief glance at these natural products, especially the substantial structural variation within a class of compounds, clearly demonstrates that Nature has long played the role of medicinal chemist. The recent explosion in genome sequencing has expanded our appreciation of natural product space and the vastness of uncharted territory that remains. One small corner of natural product chemical space is occupied by the recently dubbed thiazole/oxazole-modified microcins (TOMMs), which are ribosomally produced peptides with posttranslationally installed heterocycles derived from cysteine, serine and threonine residues. As with other classes of natural products, the genetic capacity to synthesize TOMMs has been widely disseminated among bacteria. Over the evolutionary timescale, Nature has tested countless random mutations and selected for gain of function in TOMM biosynthetic gene clusters, yielding several privileged molecular scaffolds. Today, this burgeoning class of natural products encompasses a structurally and functionally diverse set of molecules (i.e. microcin B17, cyanobactins, and thiopeptides). TOMMs presumably provide their producers with an ecological advantage. This advantage can include chemical weapons wielded in the battle for nutrients, disease-promoting virulence factors, or compounds presumably beneficial for symbiosis. Despite this plethora of functions, many TOMMs await experimental interrogation. This review will focus on the biosynthesis and natural combinatorial diversity of the TOMM family.