Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 27
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Pol Merkur Lekarski ; 51(1): 64-73, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36960903

RESUMEN

OBJECTIVE: Aim: to map MHPSS interventions for war-affected children, and to identify the barriers and facilitators for interventions target¬ing different layers of the MHPSS pyramid; to assess differences in methodology and study design to give a general outlook for potential future evaluation of interventions. PATIENTS AND METHODS: Materials and methods: A scoping review was conducted by utilising PubMed, Scopus, PsychINFO scientific databases (765 articles were found). In addition to IASC MHPSS intervention pyramid as our framework, we used a combination of inductive and de¬ductive coding to find common themes in facilitators and barriers to the effectiveness of interventions within each layer. To geographically illustrate the locations of war-affected areas and their correlating intervention types, we developed a visual map. CONCLUSION: Conclusions: The phenomenon of unequal distribution of interventions (concentrated in West Asia, North and sub-Saharan Africa, with no interventions (found in literature) in South American or South-East Asia). III-rd level of IASC MHPSS Pyramid "focused, non-specialized supports", received great deal of efforts in MHPSS interventions conducted for children in war-affected areas. Main barriers: increasing trauma-related symptoms; lack of parental or caregiver support impaired successful intervention out¬comes for war-affected children; lack of political will and financial resources, difficulties in priority-setting, or an insufficient health workforce ongoing conflicts. Main facilitators: culturally appropriate design and collaboration with local stakeholders; caregiver involvement in interventions for war-affected children.


Asunto(s)
Salud Mental , Sistemas de Apoyo Psicosocial , Humanos , Niño
2.
Nat Chem Biol ; 19(3): 251, 2023 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-36854746
3.
Nat Prod Rep ; 40(1): 174-201, 2023 01 25.
Artículo en Inglés | MEDLINE | ID: mdl-36222427

RESUMEN

Covering: up to 2022A very large group of biosynthetically linked fungal secondary metabolites are formed via the key intermediate emodin and its corresponding anthrone. The group includes anthraquinones such as chrysophanol and cladofulvin, the grisandienes geodin and trypacidin, the diphenyl ether pestheic acid, benzophenones such as monodictyphenone and various xanthones including the prenylated shamixanthones, the agnestins and dimeric xanthones such as the ergochromes, cryptosporioptides and neosartorin. Such compounds exhibit a wide range of bioactivities and as such have been utilised in traditional medicine for centuries, as well as garnering more recent interest from the pharmaceutical sector. Additional interest comes from industries such as textiles and cosmetics due to their use as natural colourants. A variety of biosynthetic routes and mechanisms have been proposed for this family of compounds, being altered and updated as new biosynthetic methods develop and new results emerge. After nearly 100 years of such research, this review aims to provide a comprehensive overview of what is currently known about the biosynthesis of this important family, amalgamating the early chemical and biosynthetic studies with the more recent genetics-based advances and comparative bioinformatics.


Asunto(s)
Productos Biológicos , Emodina , Xantonas , Emodina/metabolismo , Productos Biológicos/farmacología , Antraquinonas/farmacología , Antraquinonas/metabolismo , Xantonas/farmacología , Xantonas/química , Xantonas/metabolismo , Genómica
4.
Nat Prod Rep ; 40(1): 128-157, 2023 01 25.
Artículo en Inglés | MEDLINE | ID: mdl-36129067

RESUMEN

Covering: up to early 2022Maleidrides are a family of polyketide-based dimeric natural products isolated from fungi. Many maleidrides possess significant bioactivities, making them attractive pharmaceutical or agrochemical lead compounds. Their unusual biosynthetic pathways have fascinated scientists for decades, with recent advances in our bioinformatic and enzymatic understanding providing further insights into their construction. However, many intriguing questions remain, including exactly how the enzymatic dimerisation, which creates the diverse core structure of the maleidrides, is controlled. This review will explore the literature from the initial isolation of maleidride compounds in the 1930s, through the first full structural elucidation in the 1960s, to the most recent in vivo, in vitro, and in silico analyses.


Asunto(s)
Productos Biológicos , Policétidos , Anhídridos/metabolismo , Hongos/metabolismo , Dimerización , Vías Biosintéticas , Policétidos/metabolismo , Productos Biológicos/química
5.
6.
J Prosthet Orthot ; 34(4): 202-212, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36157327

RESUMEN

Introduction: The design and selection of lower-limb prosthetic devices is currently hampered by a shortage of evidence to drive the choice of prosthetic foot parameters. We propose a new approach wherein prostheses could be designed, specified, and provided based on individualized measurements of the benefits provided by candidate feet. In this manuscript, we present a pilot test of this evidence-based and personalized process. Methods: We previously developed a "prosthetic foot emulator," a wearable robotic system that provides users with the physical sensation of trying on different prosthetic feet before definitive fitting. Here we detail preliminary demonstrations of two possible approaches to personalizing foot design: 1) an emulation and test-drive strategy of representative commercial foot models, and 2) a prosthetist-driven tuning procedure to optimize foot parameters. Results: The first experiment demonstrated large and sometimes surprising differences in optimal prosthetic foot parameters across a variety of subjects, walking conditions, and outcome measures. The second experiment demonstrated a quick and effective simple manual tuning procedure for identifying preferred prosthetic foot parameters. Conclusions: Emulator-based approaches could improve individualization of prosthetic foot prescription. The present results motivate future clinical studies of the validity, efficacy, and economics of the approach across larger and more diverse subject populations. Clinical Relevance: Today, emulator technology is being used to accelerate research and development of novel prosthetic and orthotic devices. In the future, after further refinement and validation, this technology could benefit clinical practice by providing a means for rapid test-driving and optimal selection of clinically available prosthetic feet.

7.
Nat Chem Biol ; 18(7): 679, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35761079
8.
Methods Mol Biol ; 2489: 23-39, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35524043

RESUMEN

A suite of molecular techniques have been developed in recent decades, which allow gene clusters coding for the biosynthesis of fungal natural products to be investigated and characterized in great detail. Many of these involve the manipulation of the native producer, for example, to increase yields of natural products or investigate the biosynthetic pathway through gene disruptions. However, an alternative and powerful means of investigating biosynthetic pathways, which does not rely on a cooperative native host, is the refactoring and heterologous expression of pathways in a suitable host strain. This protocol aims to walk the reader through the various steps required for the heterologous expression of a fungal biosynthetic gene cluster, specifically using Aspergillus oryzae strain NSAR1 and the pTYGS series of expression vectors. Briefly, this process involves the design and construction of up to four multigene expression vectors using yeast recombination, PEG-mediation transformation of A. oryzae protoplasts, and chemical extraction of the resulting transformants to screen for the presence of metabolites.


Asunto(s)
Aspergillus oryzae , Productos Biológicos , Aspergillus oryzae/genética , Aspergillus oryzae/metabolismo , Productos Biológicos/metabolismo , Vías Biosintéticas/genética , Expresión Génica , Genes Fúngicos , Familia de Multigenes , Saccharomyces cerevisiae/genética
9.
Nat Chem Biol ; 18(3): 238, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35228724
10.
Nat Chem Biol ; 18(4): 354, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-35352068
11.
Fungal Biol Biotechnol ; 9(1): 2, 2022 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-35177129

RESUMEN

Maleidrides are a family of structurally related fungal natural products, many of which possess diverse, potent bioactivities. Previous identification of several maleidride biosynthetic gene clusters, and subsequent experimental work, has determined the 'core' set of genes required to construct the characteristic medium-sized alicyclic ring with maleic anhydride moieties. Through genome mining, this work has used these core genes to discover ten entirely novel putative maleidride biosynthetic gene clusters, amongst both publicly available genomes, and encoded within the genome of the previously un-sequenced epiheveadride producer Wicklowia aquatica CBS 125634. We have undertaken phylogenetic analyses and comparative bioinformatics on all known and putative maleidride biosynthetic gene clusters to gain further insights regarding these unique biosynthetic pathways.

12.
J Nat Prod ; 85(3): 572-580, 2022 03 25.
Artículo en Inglés | MEDLINE | ID: mdl-35170975

RESUMEN

Three new polyketide-derived natural products, cladobotric acids G-I (1-3), and six known metabolites (4, 5, 8-11) were isolated from fermentation of the fungus Cladobotryum sp. grown on rice. Their structures were elucidated by extensive spectroscopic methods. Two metabolites, cladobotric acid A (4) and pyrenulic acid A (10), were converted to a series of new products (12-20) by semisynthesis. The antibacterial activities of all these compounds were investigated against the Gram-positive pathogen Staphylococcus aureus including methicillin-susceptible (MSSA), methicillin-resistant and vancomycin-intermediate (MRSA/VISA), and heterogeneous vancomycin-intermediate (hVISA) strains. Results of these antibacterial assays revealed structural features of the unsaturated decalins important for biological activity.


Asunto(s)
Staphylococcus aureus Resistente a Meticilina , Infecciones Estafilocócicas , Antibacterianos/farmacología , Humanos , Pruebas de Sensibilidad Microbiana , Vancomicina
13.
Nat Chem Biol ; 18(1): 1, 2022 01.
Artículo en Inglés | MEDLINE | ID: mdl-34934189
14.
Front Fungal Biol ; 2: 632542, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-37744117

RESUMEN

The use of filamentous fungi as cellular factories, where natural product pathways can be refactored and expressed in a host strain, continues to aid the field of natural product discovery. Much work has been done to develop host strains which are genetically tractable, and for which there are multiple selectable markers and controllable expression systems. To fully exploit these strains, it is beneficial to understand their natural metabolic capabilities, as such knowledge can rule out host metabolites from analysis of transgenic lines and highlight any potential interplay between endogenous and exogenous pathways. Additionally, once identified, the deletion of secondary metabolite pathways from host strains can simplify the detection and purification of heterologous compounds. To this end, secondary metabolite production in Aspergillus oryzae strain NSAR1 has been investigated via the deletion of the newly discovered negative regulator of secondary metabolism, mcrA (multicluster regulator A). In all ascomycetes previously studied mcrA deletion led to an increase in secondary metabolite production. Surprisingly, the only detectable phenotypic change in NSAR1 was a doubling in the yields of kojic acid, with no novel secondary metabolites produced. This supports the previous claim that secondary metabolite production has been repressed in A. oryzae and demonstrates that such repression is not McrA-mediated. Strain NSAR1 was then modified by employing CRISPR-Cas9 technology to disrupt the production of kojic acid, generating the novel strain NSARΔK, which combines the various beneficial traits of NSAR1 with a uniquely clean secondary metabolite background.

15.
Front Fungal Biol ; 2: 655323, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-37744150

RESUMEN

Interrogation of an EST database for Clitopilus passeckerianus identified a putative homolog to the unusual stress response gene from yeast; ddr48, as being upregulated under pleuromutilin production conditions. Silencing of this gene, named cprp, produced a population of transformants which demonstrated significantly reduced pleuromutilin production. Attempts to complement a Saccharomyces cerevisiae ddr48 mutant strain (strain Y16748) with cprp were hampered by the lack of a clearly identifiable mutant phenotype, but interestingly, overexpression of either ddr48 or cprp in S. cerevisiae Y16748 led to a conspicuous and comparable reduction in growth rate. This observation, combined with the known role of DDR48 proteins from a range of fungal species in nutrient starvation and stress responses, raises the possibility that this family of proteins plays a role in triggering oligotrophic growth. Localization studies via the production of a Cprp:GFP fusion protein in C. passeckerianus showed clear localization adjacent to the hyphal septa and, to a lesser extent, cell walls, which is consistent with the identification of DDR48 as a cell wall-associated protein in various yeast species. To our knowledge this is the first study demonstrating that a DDR48-like protein plays a role in the regulation of a secondary metabolite, and represents the first DDR48-like protein from a basidiomycete. Potential homologs can be identified across much of the Dikarya, suggesting that this unusual protein may play a central role in regulating both primary and secondary metabolism in fungi.

16.
Org Biomol Chem ; 19(1): 182-187, 2021 01 06.
Artículo en Inglés | MEDLINE | ID: mdl-33107888

RESUMEN

Fusarochromene isolated from the plant pathogenic fungus, Fusarium sacchari is closely related to a group of mycotoxins including fusarochromanone previously isolated from various Fusaria spp. Despite their assumed polyketide biogenesis, incorporation studies with 13C-labelled acetate, glycerol and tryptophans show that fusarochromene is unexpectedly derived via oxidative cleavage of the aromatic amino acid tryptophan. A putative biosynthetic gene cluster has been identified.


Asunto(s)
Fusarium/metabolismo , Triptófano/metabolismo , Fusarium/genética , Familia de Multigenes/genética , Oxidación-Reducción
17.
Chem Sci ; 11(42): 11570-11578, 2020 Oct 07.
Artículo en Inglés | MEDLINE | ID: mdl-34094403

RESUMEN

Maleidrides are a class of bioactive secondary metabolites unique to filamentous fungi, which contain one or more maleic anhydrides fused to a 7-, 8- or 9- membered carbocycle (named heptadrides, octadrides and nonadrides respectively). Herein structural and biosynthetic studies on the antifungal octadride, zopfiellin, and nonadrides scytalidin, deoxyscytalidin and castaneiolide are described. A combination of genome sequencing, bioinformatic analyses, gene disruptions, biotransformations, isotopic feeding studies, NMR and X-ray crystallography revealed that they share a common biosynthetic pathway, diverging only after the nonadride deoxyscytalidin. 5-Hydroxylation of deoxyscytalidin occurs prior to ring contraction in the zopfiellin pathway of Diffractella curvata. In Scytalidium album, 6-hydroxylation - confirmed as being catalysed by the α-ketoglutarate dependent oxidoreductase ScyL2 - converts deoxyscytalidin to scytalidin, in the final step in the scytalidin pathway. Feeding scytalidin to a zopfiellin PKS knockout strain led to the production of the nonadride castaneiolide and two novel ring-open maleidrides.

18.
Chem Sci ; 10(10): 2930-2939, 2019 Mar 14.
Artículo en Inglés | MEDLINE | ID: mdl-30996871

RESUMEN

Three novel dimeric xanthones, cryptosporioptides A-C were isolated from Cryptosporiopsis sp. 8999 and their structures elucidated. Methylation of cryptosporioptide A gave a methyl ester with identical NMR data to cryptosporioptide, a compound previously reported to have been isolated from the same fungus. However, HRMS analysis revealed that cryptosporioptide is a symmetrical dimer, not a monomer as previously proposed, and the revised structure was elucidated by extensive NMR analysis. The genome of Cryptosporiopsis sp. 8999 was sequenced and the dimeric xanthone (dmx) biosynthetic gene cluster responsible for the production of the cryptosporioptides was identified. Gene disruption experiments identified a gene (dmxR5) encoding a cytochrome P450 oxygenase as being responsible for the dimerisation step late in the biosynthetic pathway. Disruption of dmxR5 led to the isolation of novel monomeric xanthones. Cryptosporioptide B and C feature an unusual ethylmalonate subunit: a hrPKS and acyl CoA carboxylase are responsible for its formation. Bioinformatic analysis of the genomes of several fungi producing related xanthones, e.g. the widely occurring ergochromes, and related metabolites allows detailed annotation of the biosynthetic genes, and a rational overall biosynthetic scheme for the production of fungal dimeric xanthones to be proposed.

19.
Chem Sci ; 10(1): 233-238, 2019 Jan 07.
Artículo en Inglés | MEDLINE | ID: mdl-30746079

RESUMEN

Two new dihydroxy-xanthone metabolites, agnestins A and B, were isolated from Paecilomyces variotii along with a number of related benzophenones and xanthones including monodictyphenone. The structures were elucidated by NMR analyses and X-ray crystallography. The agnestin (agn) biosynthetic gene cluster was identified and targeted gene disruptions of the PKS, Baeyer-Villiger monooxygenase, and other oxido-reductase genes revealed new details of fungal xanthone biosynthesis. In particular, identification of a reductase responsible for in vivo anthraquinone to anthrol conversion confirms a previously postulated essential step in aromatic deoxygenation of anthraquinones, e.g. emodin to chrysophanol.

20.
Nat Commun ; 9(1): 3940, 2018 09 26.
Artículo en Inglés | MEDLINE | ID: mdl-30258052

RESUMEN

Strobilurins from fungi are the inspiration for the creation of the ß-methoxyacrylate class of agricultural fungicides. However, molecular details of the biosynthesis of strobilurins have remained cryptic. Here we report the sequence of genomes of two fungi that produce strobilurins and show that each contains a biosynthetic gene cluster, which encodes a highly reducing polyketide synthase with very unusual C-terminal hydrolase and methyltransferase domains. Expression of stpks1 in Aspergillus oryzae leads to the production of prestrobilurin A when the fermentation is supplemented with a benzoyl coenzyme A (CoA) analogue. This enables the discovery of a previously unobserved route to benzoyl CoA. Reconstruction of the gene cluster in A. oryzae leads to the formation of prestrobilurin A, and addition of the gene str9 encoding an FAD-dependent oxygenase leads to the key oxidative rearrangement responsible for the creation of the ß-methoxyacrylate toxophore. Finally, two methyltransferases are required to complete the synthesis.


Asunto(s)
Basidiomycota/enzimología , Sintasas Poliquetidas/metabolismo , Estrobilurinas/metabolismo , Aspergillus oryzae , Basidiomycota/genética , Familia de Multigenes
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...