Intracellular removal of acetyl, feruloyl and p-coumaroyl decorations on arabinoxylo-oligosaccharides imported from lignocellulosic biomass degradation by Ruminiclostridium cellulolyticum.

BACKGROUND: Xylans are polysaccharides that are naturally abundant in agricultural by-products, such as cereal brans and straws. Microbial degradation of arabinoxylan is facilitated by extracellular esterases that remove acetyl, feruloyl, and p-coumaroyl decorations. The bacterium Ruminiclostridium cellulolyticum possesses the Xua (xylan utilization associated) system, which is responsible for importing and intracellularly degrading arabinoxylodextrins. This system includes an arabinoxylodextrins importer, four intracellular glycosyl hydrolases, and two intracellular esterases, XuaH and XuaJ which are encoded at the end of the gene cluster. RESULTS: Genetic studies demonstrate that the genes xuaH and xuaJ are part of the xua operon, which covers xuaABCDD'EFGHIJ. This operon forms a functional unit regulated by the two-component system XuaSR. The esterases encoded at the end of the cluster have been further characterized: XuaJ is an acetyl esterase active on model substrates, while XuaH is a xylan feruloyl- and p-coumaryl-esterase. This latter is active on oligosaccharides derived from wheat bran and wheat straw. Modelling studies indicate that XuaH has the potential to interact with arabinoxylobiose acylated with mono- or diferulate. The intracellular esterases XuaH and XuaJ are believed to allow the cell to fully utilize the complex acylated arabinoxylo-dextrins imported into the cytoplasm during growth on wheat bran or straw. CONCLUSIONS: This study reports for the first time that a cytosolic feruloyl esterase is part of an intracellular arabinoxylo-dextrin import and degradation system, completing its cytosolic enzymatic arsenal. This system represents a new pathway for processing highly-decorated arabinoxylo-dextrins, which could provide a competitive advantage to the cell and may have interesting biotechnological applications.

Evaluation of a Trametes pubescens laccase concentrated extract on allura red AC decolorization without the addition of synthetic mediators.

Synthetic dye bioremediation is a topic of great importance since these pollutants possess toxic effects, and huge quantities of them are being discharged into water bodies. Ligninolytic enzyme treatment stands out for being a cost-effective methodology, capable of obtaining high decolorization levels. In this work, a laccase enzyme treatment was evaluated to effectively perform a cycle of dye bioremediation. Furthermore, a dye decolorization improvement was also assessed through laccase immobilization. Particularly, a Trametes pubescens enzyme extract was concentrated, immobilized onto calcium alginate beads, and characterized to assess its dye decolorization potential. Ammonium sulfate precipitation and vacuum evaporation were evaluated to concentrate the crude extract and to decolorize allura red AC. Both treatments reached a high enzyme yield recovery (>90%), but only the vacuum-evaporated extract achieved a high allura red AC decolorization level after 16 h of contact time. This suggested that essential compounds for allura red AC decolorization were present in the crude extract, implying that neither a complete laccase purification process nor an addition of synthetic mediators are necessary. Under optimized immobilization conditions, 94.6% immobilization efficiency and 49.8% activity recovery were obtained with 0:1 alginate:enzyme (v/v), 100 mM CaCl2, and 5.0% w/v sodium alginate. Furthermore, by immobilizing the laccase concentrated extract, both the pH and temperature stabilities were improved. The decolorization of allura red AC by free and immobilized laccase was 68.4% and 4.6%, respectively, showing that although the enzyme stability was improved, dye decolorization was negatively affected. Thus, an efficient allura red AC decolorization was obtained with concentrated-free laccase by a feasible and low-cost methodology.

Evaluation of several white-rot fungi for the decolorization of a binary mixture of anionic dyes and characterization of the residual biomass as potential organic soil amendment.

Industrial pollution is a great concern for modern society and developing cyclic processes is one of the major challenges. As far as we know, this work is the first to report the use of multiple white-rot fungi species for degrading a binary mixture of anionic dyes under solid state fermentation (SSF) conditions and a further physicochemical characterization of the residual biomass. First, eight white-rot fungi decolorized the dye mixture of brilliant blue FCF and allura red AC adsorbed onto corncob, reaching decolorizations between 11.47% and 87.64%. Then, I. lacteus, B. adusta and T. versicolor, based on the decolorization yield, were selected to evaluate the effect of carbon:nitrogen ratio, moisture content and inoculum quantity on the decolorization percentage. The factorial designs showed that C:N ratio had a negative effect while moisture and inoculum quantity a positive effect. In terms of the kinetics, the three white-rot fungi achieved their maximum decolorization level, around 80.11-86.04%, after 10-12 days. I. lacteus exhibited the highest decolorization percentage, even though only the enzyme manganese peroxidase was detected, with a maximum activity of 6.62 U gds-1 at day 14. Besides, T. versicolor was the only species with laccase activity, with a maximum of 15.94 U gds-1 at day 6 of fermentation. The physicochemical characterization of the biomass allowed to conclude that these aggregates represent a potential organic amendment, as for their significant oxidizable organic carbon (more than 9.5% on wet basis) and essential nutrients content, as well as for their low ash content (less than 1% on wet basis). Finally, for outlining an efficient bioremediation cycle, a cheap and effective methodology for drying the biomass at the end of the SSF process is required.

Synthesis of Positional Isomeric Phenylphenalenones.

A series of isomeric phenylphenalenones in which the phenyl ring is located at all possible peripheral positions of the phenalenone nuclei was synthesized. The structural characteristics of the series, in which topological variation is permitted with minimal electronic disturbance, could, in principle, allow for easy pharmacophore recognition when the compounds are aligned in steroidomimetic conformations.

Chitosan-Acrylic Polymeric Nanoparticles with Dynamic Covalent Bonds. Synthesis and Stimuli Behavior.

Drug delivery represents one of the most important research fields within the pharmaceutical industry. Different strategies are reported every day in a dynamic search for carriers with the ability to transport drugs across the body, avoiding or decreasing toxic issues and improving therapeutic activity. One of the most interesting strategies currently under research is the development of drug delivery systems sensitive to different stimuli, due to the high potential attributed to the selective delivery of the payload. In this work, a stimuli-sensitive nanocarrier was built with a bifunctional acrylic polymer, linked by imine and disulfide bonds to thiolate chitosan, the latter being a biopolymer widely known in the field of tissue engineering and drug delivery by its biodegradability and biocompatibility. These polymer nanoparticles were exposed to different changes in pH and redox potential, which are environments commonly found inside cancer cells. The results proof the ability of the nanoparticles to keep the original structure when either changes in pH or redox potential were applied individually. However, when both stimuli were applied simultaneously, a disassembly of the nanoparticles was evident. These special characteristics make these nanoparticles suitable nanocarriers with potential for the selective delivery of anticancer drugs.

Application of the Crystalline Sponge Method to Revise the Structure of the Phenalenone Fuliginone.

The structure of fuliginone was revised from a phenyl substituted phenalenone to a hydroxyl substituted phenalenone as a result of its re-purification via HPLC with subsequent NMR analysis together with an independent synthesis and analysis of the crystal structure, which was secured via the crystalline sponge method. On-flow High Performance Liquid Chromatography coupled to Nuclear Magnetic Resonance spectroscopy (HPLC-NMR) was employed to confirm the presence of the natural product in the plant extract and to monitor for any possible degradation or conversion of the compound.

Phenylphenalenones protect banana plants from infection by Mycosphaerella fijiensis and are deactivated by metabolic conversion.

Phenylphenalenones, polycyclic aromatic natural products from some monocotyledonous plants, are known as phytoalexins in banana (Musa spp.). In this study, (1) H nuclear magnetic resonance (NMR)-based metabolomics along with liquid chromatography and mass spectrometry were used to explore the chemical responses of the susceptible 'Williams' and the resistant 'Khai Thong Ruang' Musa varieties to the ascomycete fungus Mycosphaerella fijiensis, the agent of the black leaf Sigatoka disease. Principal component analysis discriminated strongly between infected and non-infected plant tissue, mainly because of specialized metabolism induced in response to the fungus. Phenylphenalenones are among the major induced compounds, and the resistance level of the plants was correlated with the progress of the disease. However, a virulent strain of M. fijiensis was able to overcome plant resistance by converting phenylphenalenones to sulfate conjugates. Here, we report the first metabolic detoxification of fungitoxic phenylphenalenones to evade the chemical defence of Musa plants.

Synthesis of 8-Phenylphenalenones: 2-Hydroxy-8-(4-hydroxyphenyl)-1H-phenalen-1-one from Eichhornia crassipes.

2-Hydroxy-8-(4-hydroxyphenyl)-1H-phenalen-1-one (1), the first reported 8-phenylphenalenone from the roots of Eichhornia crassipes (water hyacinth), was synthesized starting from 2-methoxynaphthalene in 11 steps and with an overall yield of 2%. A cascade Friedel-Crafts/Michael annulation reaction between acryloyl chloride and 2-methoxynaphthalene afforded 9-methoxyperinaphthanone that, after transformation to 9-methoxy-2-(4-methoxyphenyl)-1H-phenalen-1-one by means of standard Suzuki-Miyaura methodology, was subjected to a reductive carbonyl transposition to afford 8-(4-methoxyphenyl)perinaphthanone. Dehydrogenation, epoxidation, and demethylation of the latter afforded 1.

Synthesis, leishmanicidal and cytotoxic activity of triclosan-chalcone, triclosan-chromone and triclosan-coumarin hybrids.

Twelve hybrids derived from triclosan were obtained via Williamson etherification of O-triclosan alkyl bromide plus chalcone and O-coumarin or O-chromone alkyl bromide plus triclosan, respectively. Structures of the products were elucidated by spectroscopic analysis. The synthesized compounds were evaluated for antileishmanial activity against L. (V) panamensis amastigotes. Cytotoxic activity was also evaluated against mammalian U-937 cells. Compounds 7-9 and 17, were active against Leishmania parasites (EC50=9.4; 10.2; 13.5 and 27.5 µg/mL, respectively) and showed no toxicity toward mammalian cells (>200 µg/mL). They are potential candidates for antileishmanial drug development. Compounds 25-27, were active and cytotoxic. Further studies using other cell types are needed in order to discriminate whether the toxicity shown by these compounds is against tumor or non-tumor cells. The results indicate that compounds containing small alkyl chains show better selectivity indices. Moreover, Michael acceptor moieties may modify both the leishmanicidal activity and cytotoxicity. Further studies are required to evaluate if the in vitro activity against Leishmania panamensis demonstrated here is also observed in vivo.

GASP: A Pan-Specific Predictor of Family 1 Glycosyltransferase Acceptor Specificity Enabled by a Pipeline for Substrate Feature Generation and Large-Scale Experimental Screening.

Glycosylation represents a major chemical challenge; while it is one of the most common reactions in Nature, conventional chemistry struggles with stereochemistry, regioselectivity, and solubility issues. In contrast, family 1 glycosyltransferase (GT1) enzymes can glycosylate virtually any given nucleophilic group with perfect control over stereochemistry and regioselectivity. However, the appropriate catalyst for a given reaction needs to be identified among the tens of thousands of available sequences. Here, we present the glycosyltransferase acceptor specificity predictor (GASP) model, a data-driven approach to the identification of reactive GT1:acceptor pairs. We trained a random forest-based acceptor predictor on literature data and validated it on independent in-house generated data on 1001 GT1:acceptor pairs, obtaining an AUROC of 0.79 and a balanced accuracy of 72%. The performance was stable even in the case of completely new GT1s and acceptors not present in the training data set, highlighting the pan-specificity of GASP. Moreover, the model is capable of parsing all known GT1 sequences, as well as all chemicals, the latter through a pipeline for the generation of 153 chemical features for a given molecule taking the CID or SMILES as input (freely available at https://github.com/degnbol/GASP). To investigate the power of GASP, the model prediction probability scores were compared to GT1 substrate conversion yields from a newly published data set, with the top 50% of GASP predictions corresponding to reactions with >50% synthetic yields. The model was also tested in two comparative case studies: glycosylation of the antihelminth drug niclosamide and the plant defensive compound DIBOA. In the first study, the model achieved an 83% hit rate, outperforming a hit rate of 53% from a random selection assay. In the second case study, the hit rate of GASP was 50%, and while being lower than the hit rate of 83% using expert-selected enzymes, it provides a reasonable performance for the cases when an expert opinion is unavailable. The hierarchal importance of the generated chemical features was investigated by negative feature selection, revealing properties related to cyclization and atom hybridization status to be the most important characteristics for accurate prediction. Our study provides a GT1:acceptor predictor which can be trained on other data sets enabled by the automated feature generation pipelines. We also release the new in-house generated data set used for testing of GASP to facilitate the future development of GT1 activity predictors and their robust benchmarking.

Coumarins from Galipea panamensis and Their Activity against Leishmania panamensis.

Two new coumarin compounds (1 and 2), phebalosin (3), its derived artifact murralongin (4), and murrangatin acetonide (5) were isolated from the leaves of Galipea panamensis. The structures of 1 and 2 were assigned as 7-{[(2R*)-3,3-dimethyloxiran-2-yl]methoxy}-8-[(2R*,3R*)-3-isopropenyloxiran-2-yl]-2H-chromen-2-one and 7-methoxy-8-(4-methyl-3-furyl)-2H-chromen-2-one, respectively, on the basis of their spectroscopic data (primarily NMR and MS). Compounds 1-3 were tested against axenic amastigote forms of Leishmania panamensis and displayed 50% effective concentrations (EC(50)) of 9.9, 10.5, and 14.1 microg/mL, respectively. These three compounds also displayed cytotoxicity (IC(50)) at concentrations of 9.7, 33.0, and 20.7 microg/mL, respectively, on human promonocytic U-937 cells.

Semisynthetic roxburghin tetra-methyl ether.

The title mol-ecule, (E)-2,3',4,5-tetra-methoxy-stilbene, C(18)H(20)O(4), is virtually planar. The angle between the two benzene rings is 4.06 (6)°. The inter-molecular inter-actions present in the structure are weak. There are C-H⋯O hydrogen bonds and C-H⋯π-electron ring inter-actions. The mol-ecules are ordered into planes that are parallel to (01). The distance between adjacent planes is about 3.3 Šand therefore π-π electron inter-actions between the aromatic planes are also plausible.

4-Phenylphenalenones as a template for new photodynamic compounds against Mycosphaerella fijiensis.

BACKGROUND: Evaluation of 4-phenylphenalenones and structural analogues against the fungal pathogen Mycosphaerella fijiensis (causal agent of black sigatoka disease in bananas) under light-controlled conditions uncovered some key structural features for the design of photodynamic compounds. RESULTS: Structure-activity relationship analysis revealed the importance of a chromophoric aryl-ketone and a steroidomimetic structural motif in the activity of the assayed compounds. The results pointed to 1,2-dihydro-3H-naphtho[2',1':3,4]cyclohepta[1,2-b]furan-3-one, which displayed an activity in the range of propiconazole but with photodynamic behaviour. CONCLUSION: The present work demonstrates that 1,2-dihydro-3H-naphtho[2',1':3,4]cyclohepta[1,2-b]heterocyclic-3-one derivatives can be used as potential lead compounds for the development of fungicides, relying on a dual mode of action. © 2015 Society of Chemical Industry.

Dimeric phenylphenalenones from Musa acuminata and various Haemodoraceae species. Crystal structure of anigorootin.

Three fused octacyclic phenylphenalenone dimers were isolated from Musa acuminata: Anigorootin, which was first isolated from Anigozanthos flavidus and hitherto represented the only compound of that type, the new 4'-hydroxy-anigorootin, and 4',4"-di-hydroxy-anigorootin, which is a revised structure. The crystal structure of anigorootin was determined by X-ray crystallography. 3,3'-Bis-hydroxyanigorufone, a dimer of the conventional type known from Anigozanthos preissii, was also found in Musa acuminata. Phytochemical analysis of several Haemodoraceae species revealed the occurrence of anigorootin, 3,3'-bis-hydroxyanigorufone, and the novel metabolite 3,3'-bis-anigorufone. The occurrence of the same compounds in Musaceae and Haemodoraceae indicates the close chemotaxonomic relationship of both plant families.

Radical scavenging capacity of 2,4-dihydroxy-9-phenyl-1H-phenalen-1-one: a functional group exclusion approach.

2,4-Dihydroxy-9-phenyl-1H-phenalen-1-one (4-hydroxyanigorufone, 1), a compound isolated from Anigozanthos flavidus and Monochoria elata, displayed a high radical scavenging capacity in the ORAC assay. A systematic approach was adopted in order to explore the effect of each functional group. H-Atom transfer from the phenolic hydroxyl, a captodative effect from the hydroxy ketone, and the presumed involvement of the phenyl ring in the termination step of the radical reaction were disclosed as relevant features of this type of antioxidant.

[Prevalence of Depressive and Anxious Symptomatology in 14-18 ys-old Students from a Private School in Medellin]. / Prevalencia de sintomatología depresiva y ansiosa en estudiantes de 14 a 18 años de un colegio privado de Medellín.

OBJECTIVE: This study describes prevalence of depressive and anxious symptoms together with family, environmental and personal risk factors in a group of adolescents between 14 and 18 years of age in a private school of Medellín. METHODS: An analytic observational cross sectional study was performed in 152 adolescents, evaluating sociodemographic aspects and prevalence of depressive and anxious symptomatology, as established through BDI-II and BAI. RESULTS: Average age was 15.4 ± 0.9 years old, with a 25% prevalence of anxiety symptoms and 25.7% of depressive symptoms. From the 38 (25%) students with BAI positive, 26 (68.4%) were BDI positive, and from the 39 (25.6%) students with BDI positive, 26 (66.7%) were BAI positive. CONCLUSIONS: the risk factors for anxiety and depressive symptomatology were: being a woman, being a victim of bullying and abuse. Having friends was the protective factors for depressive symptomatology. There was a statistical association between self-report of depressive and anxiety symptomatology; between the anxiety self-report and the depressive symptomatology; as well as between depressive and anxiety symptomatology and parents' perception of such symptoms.

O-Methylation of phenylphenalenone phytoalexins in Musaacuminata and Wachendorfia thyrsiflora.

Biosynthetic O-methylation at various sites along the backbone of inducible phenylphenalenones in Musaacuminata var. "Williams" (Musaceae) and Wachendorfiathyrsiflora (Haemodoraceae) was investigated using 13C-labelled precursors. The inducibility of O-methylated metabolites was demonstrated in both species and the origin of methoxyl group from [methyl-13C]L-methionine was confirmed. In addition to known phenylphenalenones, a methoxylated metabolite, 4-(4-hydroxy-3-methoxy-phenyl)-benzo[de]isochromene-1,3-dione, was detected and its structure elucidated mainly by NMR spectroscopic techniques. The experiments were used to discriminate methionine-derived and artificial methoxy groups formed during methanolic extraction. Finally, demethylation of 4'-methoxycinnamic acid and subsequent conversion to 3',4'-methylenedioxycinnamic acid was demonstrated in M.acuminata.

Structure-activity relationship in the interaction of substituted perinaphthenones with Mycosphaerella fijiensis.

The levels of native fungitoxic perinaphthenone phytoalexins in susceptible Musa varieties (banana), which are commercially grown in large plantations, are too low to provide plants with long-lasting protection against highly pathogenic fungi. Novel strategies for plant protection are necessary to reduce crop losses and to prevent the development of resistant fungal strains. The synthesis of novel fungicides based on the structures of perinaphthenone natural products is considered to be a promising strategy. Thirteen substituted perinaphthenones, among them two known natural products (1, 2) and 11 synthetics (3-13), were evaluated for their activity against Mycosphaerella fijiensis , and their half-maximal inhibitory concentrations (IC(50)) were calculated to establish structure-activity relationships (SAR). A SAR trend was hypothesized, leading to the design of a new compound, 4-methoxy-2-nitro-1H-phenalen-1-one (14); the new compound displayed significantly enhanced in vitro activity against M. fijiensis compared to other perinaphthenone derivatives. The activity of 14 was comparable to that of two commercial fungicides.

Phenalenone-type compounds from Musa acuminata var. "Yangambi km 5" (AAA) and their activity against Mycosphaerella fijiensis.

Two perinaphthenone-type compounds (1 and 2) were isolated together with four known phenylphenalenones (3-6) from the rhizomes of Musa acuminata var. "Yangambi km 5". The structures of the new phenalenones were assigned as 2-hydroxy-1H-phenalen-1-one (1) and 2-methoxy-1H-phenalen-1-one (2) on the basis of their spectroscopic data and were confirmed by synthesis. Compounds 1 and 2 displayed significantly enhanced activity against Mycosphaerella fijiensis in comparison with other phenylphenalenones.

Prevalencia de sintomatología depresiva y ansiosa en estudiantes de 14 a 18 años de un colegio privado de Medellín / Prevalence of Depressive and Anxious Symptomatology in 14-18 ys-old Students from a Private School in Medellin

Introducción: Este estudio busca determinar la prevalencia de los síntomas depresivos, ansiosos y factores de riesgo familiares, medioambientales y personales, en una población de adolescentes entre 14 y 18 años de edad de un colegio privado de Medellín. Métodos: Estudio observacional analítico de corte. Se aplicó una encuesta sociodemográfica, y las escalas de BAI (inventario de ansiedad de Beck) y BDI- II (inventario de depresión de Beck-II), para detectar la presencia de sintomatología ansiosa y depresiva. Resultados: Se encuestaron 152 adolescentes, el promedio de edad fue de 15,4 ± 0,9 años, la prevalencia de síntomas ansiosos fue de 25%, y de síntomas depresivos, de 25,7%. De los 38 (25%) estudiantes que tuvieron puntajes positivos en el BAI, 26 (68,4%) presentaron puntajes positivos en el BDI, y de los 39 (25,6%) alumnos que tuvieron puntajes positivos para BDI, en 26 (66,7%) se hallaron puntajes positivos para el BAI. Conclusiones: Los factores de riesgo para sintomatología ansiosa y depresiva fueron: ser mujer, ser víctima de matoneo y el maltrato. Tener amigos fue factor protector para sintomatología depresiva. Se encontró asociación estadística entre el autorreporte de sintomatología depresiva en el adolescente y sintomatología de ansiedad; entre el autorreporte de ansiedad con sintomatología depresiva; de igual manera, entre la sintomatología de depresión y ansiedad y la percepción de los padres para dichos síntomas.

Objective: This study describes prevalence of depressive and anxious symptoms together with family, environmental and personal risk factors in a group of adolescents between 14 and 18 years of age in a private school of Medellín. Methods: An analytic observational cross sectional study was performed in 152 adolescents, evaluating sociodemographic aspects and prevalence of depressive and anxious symptomatology, as established through BDI-II and BAI. Results: Average age was 15.4 ± 0.9 years old, with a 25% prevalence of anxiety symptoms and 25.7% of depressive symptoms. From the 38 (25%) students with BAI positive, 26 (68.4%) were BDI positive, and from the 39 (25.6%) students with BDI positive, 26 (66.7%) were BAI positive. Conclusions: the risk factors for anxiety and depressive symptomatology were: being a woman, being a victim of bullying and abuse. Having friends was the protective factors for depressive symptomatology. There was a statistical association between self-report of depressive and anxiety symptomatology; between the anxiety self-report and the depressive symptomatology; as well as between depressive and anxiety symptomatology and parents' perception of such symptoms.