RESUMO
BACKGROUND: ß-Arbutin, found in the leaves of bearberry, stands out as one of the globally acknowledged eco-friendly whitening additives in recent years. However, the natural abundance of ß-Arbutin is low, and the cost-effectiveness of using chemical synthesis or plant extraction methods is low, which cannot meet the requirements. While modifying the ß-Arbutin synthesis pathway of existing strains is a viable option, it is hindered by the limited synthesis capacity of these strains, which hinders further development and application. RESULTS: In this study, we established a biosynthetic pathway in Komagataella phaffii for ß-Arbutin production with a titer of 1.58 g/L. Through diverse metabolic strategies, including fusion protein construction, enhancing shikimate pathway flux, and augmenting precursor supplies (PEP, E4P, and UDPG), we significantly increased ß-Arbutin titer to 4.32 g/L. Further optimization of methanol concentration in shake flasks led to a titer of 6.32 g/L titer after 120 h of fermentation, representing a fourfold increase over the initial titer. In fed-batch fermentation, strain UA3-10 set a record with the highest production to date, reaching 128.6 g/L in a 5 L fermenter. CONCLUSIONS: This is the highest yield in the fermentation tank level of using microbial cell factories for de novo synthesis of ß-Arbutin. Applying combinatorial engineering strategies has significantly improved the ß-Arbutin yield in K. phaffii and is a promising approach for synthesizing functional products using a microbial cell factory. This study not only advances low-cost fermentation-based production of ß-Arbutin but also establishes K. phaffii as a promising chassis cell for synthesizing other aromatic amino acid metabolites.
Assuntos
Arbutina , Fermentação , Engenharia Metabólica , Saccharomycetales , Engenharia Metabólica/métodos , Arbutina/biossíntese , Arbutina/metabolismo , Saccharomycetales/metabolismo , Vias BiossintéticasRESUMO
Stevioside (5-10%) and rebaudioside-A (2-4%) are well-characterized diterpene glycosides found in leaves of Stevia rebaudiana known to have natural sweetening properties with zero glycaemic index. Stevioside has after-taste bitterness, whereas rebaudioside-A is sweet in taste. The ratio of rebaudioside-A to stevioside needs to be changed in order to increase the effectiveness and palatability of this natural sweetener. Plant-specific miRNAs play a significant role in the regulation of metabolic pathways for the biosynthesis of economically important secondary metabolites. In this study inhibition of miRNA through antisense technology was employed to antagonize the repressive action of miRstv_7 on its target mRNAs involved in the steviol glycosides (SGs) biosynthesis pathway. In transgenic plants expressing anti-miRstv_7, reduced expression level of endogenous miRstv_7 was observed than the non-transformed plants. As a result, enhanced expression of target genes, viz. KO (Kaurene oxidase), KAH (Kaurenoic acid-13-hydroxylase), and UGT76G1 (UDP-glycosyltransferase 76G1) led to a significant increase in the rebaudioside-A to stevioside ratio. Furthermore, metabolome analysis revealed a significant increase in total steviol glycosides content as well as total flavonoids content. Thus, our study can be utilized to generate more palatable varieties of Stevia with improved nutraceutical values including better organoleptic and antioxidant properties.
Assuntos
Antioxidantes , Vias Biossintéticas , Diterpenos do Tipo Caurano , MicroRNAs , Stevia , Stevia/genética , Stevia/metabolismo , Diterpenos do Tipo Caurano/metabolismo , Antioxidantes/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Vias Biossintéticas/genética , Glucosídeos/metabolismo , Glucosídeos/biossíntese , Plantas Geneticamente Modificadas , Edulcorantes/farmacologia , Edulcorantes/metabolismo , Regulação da Expressão Gênica de Plantas , Folhas de Planta/metabolismo , Folhas de Planta/genética , Glicosídeos/biossíntese , Glicosídeos/metabolismoRESUMO
Bioinformatic analysis revealed that the genomes of ubiquitous Penicillium spp. might carry dozens of biosynthetic gene clusters (BGCs), yet many clusters have remained uncharacterized. In this study, a detailed investigation of co-culture fermentation including the basidiomycete Armillaria mellea CPCC 400891 and the P. brasilianum CGMCC 3.4402 enabled the isolation of five new compounds including two bisabolene-type sesquiterpenes (arpenibisabolanes A and B), two carotane-type sesquiterpenes (arpenicarotanes A and B), and one polyketide (arpenichorismite A) along with seven known compounds. The assignments of their structures were deduced by the extensive analyses of detailed spectroscopic data, electronic circular dichroism spectra, together with delimitation of the biogenesis. Most new compounds were not detected in monocultures under the same fermentation conditions. Arpenibisabolane A represents the first example of a 6/5-fused bicyclic bisabolene. The bioassay of these five new compounds exhibited no cytotoxic activities in vitro against three human cancer cell lines (A549, MCF-7, and HepG2). Moreover, sequence alignments and bioinformatic analysis to other metabolic pathways, two BGCs including Pb-bis and Pb-car, responsible for generating sesquiterpenoids from co-culture were identified, respectively. Furthermore, based on the chemical structures and deduced gene functions of the two clusters, a hypothetic metabolic pathway for biosynthesizing induced sesquiterpenoids was proposed. These results demonstrated that the co-culture approach would facilitate bioprospecting for new metabolites even from the well-studied microbes. Our findings would provide opportunities for further understanding of the biosynthesis of intriguing sesquiterpenoids via metabolic engineering strategies. KEY POINTS: ⢠Penicillium and Armillaria co-culture facilitates the production of diverse secondary metabolites ⢠Arpenibisabolane A represents the first example of 6/5-fused bicyclic bisabolenes ⢠A hypothetic metabolic pathway for biosynthesizing induced sesquiterpenoids was proposed.
Assuntos
Armillaria , Técnicas de Cocultura , Fermentação , Penicillium , Metabolismo Secundário , Sesquiterpenos , Armillaria/metabolismo , Armillaria/genética , Penicillium/metabolismo , Penicillium/genética , Penicillium/química , Sesquiterpenos/metabolismo , Sesquiterpenos/química , Humanos , Família Multigênica , Linhagem Celular Tumoral , Vias Biossintéticas/genética , Policetídeos/metabolismo , Policetídeos/química , Policetídeos/isolamento & purificação , Células Hep G2RESUMO
Episomal AMA1-based plasmids are increasingly used for expressing biosynthetic pathways and CRISPR/Cas systems in filamentous fungi cell factories due to their high transformation efficiency and multicopy nature. However, the gene expression from AMA1 plasmids has been observed to be highly heterogeneous in growing mycelia. To overcome this limitation, here we developed next-generation AMA1-based plasmids that ensure homogeneous and strong expression. We achieved this by evaluating various degradation tags fused to the auxotrophic marker gene on the AMA1 plasmid, which introduces a more stringent selection pressure throughout multicellular fungal growth. With these improved plasmids, we observed in Aspergillus nidulans a 5-fold increase in the expression of a fluorescent reporter, a doubling in the efficiency of a CRISPRa system for genome mining, and a up to a 10-fold increase in the production of heterologous natural product metabolites. This strategy has the potential to be applied to diverse filamentous fungi.
Assuntos
Aspergillus nidulans , Sistemas CRISPR-Cas , Plasmídeos , Aspergillus nidulans/genética , Aspergillus nidulans/metabolismo , Plasmídeos/genética , Expressão Gênica , Engenharia Metabólica/métodos , Vias Biossintéticas/genética , Produtos Biológicos/metabolismoRESUMO
BACKGROUND: Diviner's sage (Salvia divinorum; Lamiaceae) is the source of the powerful hallucinogen salvinorin A (SalA). This neoclerodane diterpenoid is an agonist of the human Κ-opioid receptor with potential medical applications in the treatment of chronic pain, addiction, and post-traumatic stress disorder. Only two steps of the approximately twelve step biosynthetic sequence leading to SalA have been resolved to date. RESULTS: To facilitate pathway elucidation in this ethnomedicinal plant species, here we report a chromosome level genome assembly. A high-quality genome sequence was assembled with an N50 value of 41.4 Mb and a BUSCO completeness score of 98.4%. The diploid (2n = 22) genome of ~ 541 Mb is comparable in size and ploidy to most other members of this genus. Two diterpene biosynthetic gene clusters were identified and are highly enriched in previously unidentified cytochrome P450s as well as crotonolide G synthase, which forms the dihydrofuran ring early in the SalA pathway. Coding sequences for other enzyme classes with likely involvement in downstream steps of the SalA pathway (BAHD acyl transferases, alcohol dehydrogenases, and O-methyl transferases) were scattered throughout the genome with no clear indication of clustering. Differential gene expression analysis suggests that most of these genes are not inducible by methyl jasmonate treatment. CONCLUSIONS: This genome sequence and associated gene annotation are among the highest resolution in Salvia, a genus well known for the medicinal properties of its members. Here we have identified the cohort of genes responsible for the remaining steps in the SalA pathway. This genome sequence and associated candidate genes will facilitate the elucidation of SalA biosynthesis and enable an exploration of its full clinical potential.
Assuntos
Diterpenos Clerodânicos , Genoma de Planta , Salvia , Salvia/genética , Salvia/metabolismo , Cromossomos de Plantas/genética , Família Multigênica , Vias Biossintéticas/genéticaRESUMO
Plants are chemical engineers par excellence. Collectively they make a vast array of structurally diverse specialized metabolites. The raw materials for building new pathways (genes encoding biosynthetic enzymes) are commonly recruited directly or indirectly from primary metabolism. Little is known about how new metabolic pathways and networks evolve in plants, or what key nodes contribute to branches that lead to the biosynthesis of diverse chemicals. Here we review the molecular mechanisms underlying the generation of biosynthetic branchpoints. We also consider examples in which new metabolites are formed through the joining of precursor molecules arising from different biosynthetic routes, a scenario that greatly increases both the diversity and complexity of specialized metabolism. Given the emerging importance of metabolic gene clustering in helping to identify new enzymes and pathways, we further cover the significance of biosynthetic gene clusters in relation to metabolic networks and dedicated biosynthetic pathways. In conclusion, an improved understanding of the branchpoints between metabolic pathways will be key in order to be able to predict and illustrate the complex structure of metabolic networks and to better understand the plasticity of plant metabolism. This article is part of the theme issue 'The evolution of plant metabolism'.
Assuntos
Redes e Vias Metabólicas , Plantas , Plantas/metabolismo , Plantas/genética , Vias Biossintéticas , Família Multigênica , Evolução Biológica , Evolução MolecularRESUMO
The important role of dihydroxynaphthalene-(DHN) melanin in enhancing fungal stress resistance and its importance in fungal development and pathogenicity are well-established. This melanin also aids biocontrol fungi in surviving in the environment and effectively infecting insects. However, the biosynthetic origin of melanin in the biocontrol agents, Metarhizium spp., has remained elusive due to the complexity resulting from the divergence of two DHN-like biosynthetic pathways. Through the heterologous expression of biosynthetic enzymes from these two pathways in baker's yeast Saccharomyces cerevisiae, we have confirmed the presence of DHN biosynthesis in M. roberstii, and discovered a novel naphthopyrone intermediate, 8, that can produce a different type of pigment. These two pigment biosynthetic pathways differ in terms of polyketide intermediate structures and subsequent modification steps. Stress resistance studies using recombinant yeast cells have demonstrated that both DHN and its intermediates confer resistance against UV light prior to polymerization; a similar result was observed for its naphthopyrone counterpart. This study contributes to the understanding of the intricate and diverse biosynthetic mechanisms of fungal melanin and has the potential to enhance the application efficiency of biocontrol fungi such as Metarhizium spp. in agriculture.
Assuntos
Vias Biossintéticas , Melaninas , Metarhizium , Saccharomyces cerevisiae , Metarhizium/metabolismo , Metarhizium/genética , Melaninas/metabolismo , Melaninas/biossíntese , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Naftóis/metabolismo , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Raios UltravioletaRESUMO
The isonitrile group is a compact, electron-rich moiety coveted for its commonplace as a building block and bioorthogonal functionality in synthetic chemistry and chemical biology. Hundreds of natural products containing an isonitrile group with intriguing bioactive properties have been isolated from diverse organisms. Our recent discovery of a conserved biosynthetic gene cluster in some Actinobacteria species highlighted a novel enzymatic pathway to isonitrile formation involving a non-heme iron(II) and α-ketoglutarate-dependent dioxygenase. Here, we focus this chapter on recent advances in understanding and probing the biosynthetic machinery for isonitrile synthesis by non-heme iron(II) and α-ketoglutarate-dependent dioxygenases. We will begin by describing how to harness isonitrile enzymatic machinery through heterologous expression, purification, synthetic strategies, and in vitro biochemical/kinetic characterization. We will then describe a generalizable strategy to probe the mechanism for isonitrile formation by combining various spectroscopic methods. The chapter will also cover strategies to study other enzyme homologs by implementing coupled assays using biosynthetic pathway enzymes. We will conclude this chapter by addressing current challenges and future directions in understanding and engineering isonitrile synthesis.
Assuntos
Nitrilas , Nitrilas/metabolismo , Nitrilas/química , Ácidos Cetoglutáricos/metabolismo , Oxirredutases/metabolismo , Oxirredutases/genética , Oxirredutases/química , Família Multigênica , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Ferro/metabolismo , Ferro/química , Vias Biossintéticas , Dioxigenases/metabolismo , Dioxigenases/genética , Dioxigenases/química , Cinética , Actinobacteria/enzimologia , Actinobacteria/genética , Actinobacteria/metabolismoRESUMO
Neohesperidin is a flavonoid glycoside widely used in the food and pharmaceutical industries. The current production of neohesperidin mainly relies on extraction from plants. Microbial fermentation demonstrates a promising prospect as an environmentally friendly, efficient, and economical method. In this study, we designed and constructed the biosynthetic pathway of neohesperidin in an Escherichia coli strain by introducing the glycosyltransferase UGT73B2 from Arabidopsis thaliana, rhamnose synthase VvRHM-NRS from Vitis vinifera, and rhamnose transferase Cm1,2RhaT from Citrus maxima. After optimization of the module and the uridine diphosphate (UDP)-glucose synthetic pathway, the engineered strain produced 4.64 g/L neohesperidin in a 5 L bioreactor, and the molar conversion rate of hesperetin was 45.8%. This has been the highest titer reported to date for the biosynthesis of neohesperidin in microorganisms. This study lays a foundation for the construction and application of strains with high yields of neohesperidin and provides a potential choice for the microbial production of other flavonoid glycosides.
Assuntos
Escherichia coli , Hesperidina , Engenharia Metabólica , Hesperidina/metabolismo , Hesperidina/biossíntese , Hesperidina/análogos & derivados , Escherichia coli/genética , Escherichia coli/metabolismo , Glicosiltransferases/genética , Glicosiltransferases/metabolismo , Arabidopsis/genética , Citrus , Fermentação , Vias Biossintéticas/genética , VitisRESUMO
Background/Objectives:Agriophyllum squarrosum (L.) Moq. (A. squarrosum), also known as sandrice, is an important medicinal plant widely distributed in dunes across all the deserts of China. Common garden trials have shown content variations in flavonoids among the ecotypes of sandrice, which correlated with temperature heterogeneity in situ. However, there have not been any environmental control experiments to further elucidate whether the accumulation of flavonoids was triggered by cold stress; Methods: This study conducted a four-day ambient 4 °C low-temperature treatment on three ecotypes along with an in situ annual mean temperature gradient (Dulan (DL), Aerxiang (AEX), and Dengkou (DK)); Results: Target metabolomics showed that 12 out of 14 flavonoids in sandrice were driven by cold stress. Among them, several flavonoids were significantly up-regulated, such as naringenin and naringenin chalcone in all three ecotypes; isorhamnetin, quercetin, dihydroquercetin, and kaempferol in DL and AEX; and astragalin in DK. They were accompanied by 19 structural genes of flavonoid synthesis and 33 transcription factors were markedly triggered by cold stress in sandrice. The upstream genes, AsqAEX006535-CHS, AsqAEX016074-C4H, and AsqAEX004011-4CL, were highly correlated with the enrichment of naringenin, which could be fine-tuned by AsqAEX015868-bHLH62, AsqAEX001711-MYB12, and AsqAEX002220-MYB1R1; Conclusions: This study sheds light on how desert plants like sandrice adapt to cold stress by relying on a unique flavonoid biosynthesis mechanism that regulating the accumulation of naringenin. It also supports the precise development of sandrice for the medicinal industry. Specifically, quercetin and isorhamnetin should be targeted for development in DL and AEX, while astragalin should be precisely developed in DK.
Assuntos
Resposta ao Choque Frio , Flavonoides , Regulação da Expressão Gênica de Plantas , Plantas Medicinais , Flavonoides/biossíntese , Flavonoides/metabolismo , Plantas Medicinais/genética , Plantas Medicinais/metabolismo , Temperatura Baixa , China , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Clima Desértico , Vias BiossintéticasRESUMO
Understanding human, animal, and environmental microbiota is essential for advancing global health and combating antimicrobial resistance (AMR). We investigate the oral and gut microbiota of 48 animal species in captivity, comparing them to those of wildlife animals. Specifically, we characterize the microbiota composition, metabolic pathways, AMR genes, and biosynthetic gene clusters (BGCs) encoding the production of specialized metabolites. Our results reveal a high diversity of microbiota, with 585 novel species-level genome bins (SGBs) and 484 complete BGCs identified. Functional gene analysis of microbiomes shows diet-dependent variations. Furthermore, by comparing our findings to wildlife-derived microbiomes, we observe the impact of captivity on the animal microbiome, including examples of converging microbiome compositions. Importantly, our study identifies AMR genes against commonly used veterinary antibiotics, as well as resistance to vancomycin, a critical antibiotic in human medicine. These findings underscore the importance of the 'One Health' approach and the potential for zoonotic transmission of pathogenic bacteria and AMR. Overall, our study contributes to a better understanding of the complexity of the animal microbiome and highlights its BGC diversity relevant to the discovery of novel antimicrobial compounds.
Assuntos
Animais Selvagens , Animais de Zoológico , Antibacterianos , Microbioma Gastrointestinal , Microbiota , Animais , Animais Selvagens/microbiologia , Animais de Zoológico/microbiologia , Microbioma Gastrointestinal/genética , Antibacterianos/farmacologia , Microbiota/genética , Microbiota/efeitos dos fármacos , Bactérias/genética , Bactérias/metabolismo , Bactérias/classificação , Bactérias/efeitos dos fármacos , Família Multigênica , Humanos , Biodiversidade , Farmacorresistência Bacteriana/genética , Vancomicina/farmacologia , Vias Biossintéticas/genéticaRESUMO
Nickel (Ni) is an abundant element on Earth and it can be toxic to all forms of life. Unlike our knowledge of other metals, little is known about the biochemical response to Ni overload. Previous studies in mammals have shown that Ni induces various physiological changes including redox stress, hypoxic responses, as well as cancer progression pathways. However, the primary cellular targets of nickel toxicity are unknown. Here, we used the environmental fungus Cryptococcus neoformans as a model organism to elucidate the cellular response to exogenous Ni. We discovered that Ni causes alterations in ergosterol (the fungal equivalent of mammalian cholesterol) and lipid biosynthesis, and that the Sterol Regulatory Element-Binding transcription factor Sre1 is required for Ni tolerance. Interestingly, overexpression of the C-4 methyl sterol oxidase gene ERG25, but not other genes in the ergosterol biosynthesis pathway tested, increases Ni tolerance in both the wild type and the sre1Δ mutant. Overexpression of ERG25 with mutations in the predicted binding pocket to a metal cation cofactor sensitizes Cryptococcus to nickel and abolishes its ability to rescue the Ni-induced growth defect of sre1Δ. As overexpression of a known nickel-binding protein Ure7 or Erg3 with a metal binding pocket similar to Erg25 does not impact on nickel tolerance, Erg25 does not appear to simply act as a nickel sink. Furthermore, nickel induces more profound and specific transcriptome changes in ergosterol biosynthetic genes compared to hypoxia. We conclude that Ni targets the sterol biosynthesis pathway primarily through Erg25 in fungi. Similar to the observation in C. neoformans, Ni exposure reduces sterols in human A549 lung epithelial cells, indicating that nickel toxicity on sterol biosynthesis is conserved.
Assuntos
Cryptococcus neoformans , Níquel , Níquel/metabolismo , Níquel/toxicidade , Cryptococcus neoformans/genética , Cryptococcus neoformans/metabolismo , Cryptococcus neoformans/efeitos dos fármacos , Humanos , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Ergosterol/biossíntese , Ergosterol/metabolismo , Esteróis/metabolismo , Esteróis/biossíntese , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Células A549 , Oxirredutases/genética , Oxirredutases/metabolismo , Proteínas de Ligação a Elemento Regulador de Esterol/metabolismo , Proteínas de Ligação a Elemento Regulador de Esterol/genética , Vias Biossintéticas/genética , Oxigenases de Função MistaRESUMO
Phenazine natural products are a class of nitrogen-containing heterocyclic compounds produced by microorganisms. The tricyclic ring molecules show various chemical structures and extensive pharmacological activities, such as antimicrobial, anticancer, antiparasitic, anti-inflammatory, and insecticidal activities, with low toxicity to the environment. Since phenazine-1-carboxylic acid has been developed as a registered biopesticide, the application of phenazine natural products will be promising in the field of agriculture pathogenic fungi control based on broad-spectrum antifungal activity, minimal toxicity to the environment, and improvement of crop production. Currently, there are still plenty of intriguing hidden biosynthetic pathways of phenazine natural products to be discovered, and the titer of naturally occurring phenazine natural products is insufficient for agricultural applications. In this review, we spotlight the progress regarding biosynthesis and metabolic engineering research of phenazine natural products in the past decade. The review provides useful insights concerning phenazine natural products production and more clues on new phenazine derivatives biosynthesis.
Assuntos
Produtos Biológicos , Fungos , Engenharia Metabólica , Fenazinas , Fenazinas/metabolismo , Fenazinas/química , Produtos Biológicos/metabolismo , Produtos Biológicos/química , Fungos/metabolismo , Fungos/genética , Vias Biossintéticas , Bactérias/metabolismo , Bactérias/genéticaRESUMO
Bacterial trans-acyltransferase polyketide synthases (trans-AT PKSs) are among the most complex enzymes, which are responsible for generating a wide range of natural products, identified as trans-AT polyketides. These polyketides have received significant attention in drug development due to their structural diversity and potent bioactivities. With approximately 300 synthesized molecules discovered so far, trans-AT PKSs are found widespread in bacteria. Their biosynthesis pathways exhibit considerable genetic diversity, leading to the emergence of numerous enzymes with novel mechanisms, serving as a valuable resource for genetic engineering aimed at modifying small molecules' structures and creating new engineered enzymes. Despite the systematic discussions on trans-AT polyketides and their biosynthesis in earlier studies, the continuous advancements in tools, methods, compound identification, and biosynthetic pathways require a fresh update on accumulated knowledge. This review seeks to provide a comprehensive discussion for the 27 types of trans-AT polyketides discovered within the last seven years, detailing their sources, structures, biological activities, and biosynthetic pathways. By reviewing this new knowledge, a more profound understanding of the trans-AT polyketide family can be achieved.
Assuntos
Bactérias , Vias Biossintéticas , Policetídeo Sintases , Policetídeos , Policetídeos/metabolismo , Policetídeos/química , Policetídeo Sintases/metabolismo , Policetídeo Sintases/genética , Policetídeo Sintases/química , Bactérias/metabolismo , Bactérias/genética , Bactérias/enzimologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/química , Descoberta de Drogas , HumanosRESUMO
The concept of the gut-kidney axis is gaining significant attention due to the close relationship between gut microbiota and kidney disease. Peritoneal dialysis is recognized as a crucial renal replacement therapy for end-stage renal disease (ESRD). The alterations in gut microbiota and related mechanisms after receiving this dialysis method are not fully understood. This study conducted shotgun metagenomic sequencing on fecal samples from 11 end-stage renal disease patients who did not receive dialysis (ESRD_N) and 7 patients who received peritoneal dialysis (ESRD_P). After quality control and correlation analysis of the data, our study is aimed at exploring the impact of peritoneal dialysis on the gut microbiota and health of ESRD patients. Our research findings indicate that the complexity and aggregation characteristics of gut microbiota interactions increase in ESRD_P. In addition, the gut microbiota drives the biosynthesis pathways of sesquiterpenes and triterpenes in ESRD_P patients, which may contribute to blood purification and improve circulation. Therefore, our research will lay the foundation for the prevention and treatment of ESRD.
Assuntos
Fezes , Microbioma Gastrointestinal , Falência Renal Crônica , Diálise Peritoneal , Sesquiterpenos , Triterpenos , Humanos , Falência Renal Crônica/terapia , Falência Renal Crônica/metabolismo , Falência Renal Crônica/microbiologia , Sesquiterpenos/metabolismo , Masculino , Feminino , Fezes/microbiologia , Pessoa de Meia-Idade , Triterpenos/metabolismo , Bactérias/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Vias Biossintéticas , Adulto , Metagenômica , IdosoRESUMO
Sesquiterpene lactones (STLs) are a prominent group of plant secondary metabolites predominantly found in the Asteraceae family and have multiple ecological roles and medicinal applications. This review describes the evolutionary and ecological significance of STLs, highlighting their roles in plant defence mechanisms against herbivory and as phytotoxins, alongside their function as environmental signalling molecules. We also cover the substantial role of STLs in medicine and their mode of action in health and disease. We discuss the biosynthetic pathways and the various modifications that make STLs one of the most diverse groups of metabolites. Finally, we discuss methods for identifying and predicting STL biosynthesis pathways. This article is part of the theme issue 'The evolution of plant metabolism'.
Assuntos
Lactonas , Sesquiterpenos , Lactonas/metabolismo , Sesquiterpenos/metabolismo , Asteraceae/química , Plantas/química , Plantas/metabolismo , Vias BiossintéticasRESUMO
The flavonoid pathway is characteristic of land plants and a central biosynthetic component enabling life in a terrestrial environment. Flavonoids provide tolerance to both abiotic and biotic stresses and facilitate beneficial relationships, such as signalling to symbiont microorganisms, or attracting pollinators and seed dispersal agents. The biosynthetic pathway shows great diversity across species, resulting principally from repeated biosynthetic gene duplication and neofunctionalization events during evolution. Such events may reflect a selection for new flavonoid structures with novel functions that enable occupancy of varied ecological niches. However, the biochemical and genetic diversity of the pathway also likely resulted from evolution along parallel trends across land plant lineages, producing variant compounds with similar biological functions. Analyses of the wide range of whole-plant genome sequences now available, particularly for archegoniate plants, have enabled proposals on which genes were ancestral to land plants and which arose within the land plant lineages. In this review, we discuss the emerging proposals for how the flavonoid pathway may have evolved and diversified. This article is part of the theme issue 'The evolution of plant metabolism'.
Assuntos
Flavonoides , Flavonoides/biossíntese , Evolução Molecular , Vias Biossintéticas , Embriófitas/genética , Plantas/genética , Plantas/metabolismoRESUMO
The only known pathway for biosynthesis of the polyamine norspermidine starts from aspartate ß-semialdehyde to form the diamine 1,3-diaminopropane, which is then converted to norspermidine via a carboxynorspermidine intermediate. This pathway is found primarily in the Vibrionales order of the γ-Proteobacteria. However, norspermidine is also found in other species of bacteria and archaea, and in diverse single-celled eukaryotes, chlorophyte algae and plants that do not encode the known norspermidine biosynthetic pathway. We reasoned that products of polyamine catabolism could be an alternative route to norspermidine production. 1,3-diaminopropane is formed from terminal catabolism of spermine and spermidine, and norspermidine can be formed from catabolism of thermospermine. We found that the single-celled chlorophyte alga Chlamydomonas reinhardtii thermospermine synthase (CrACL5) did not aminopropylate exogenously-derived 1,3-diaminopropane efficiently when expressed in Escherichia coli. In contrast, it completely converted all E. coli native spermidine to thermospermine. Co-expression in E. coli of the polyamine oxidase 5 from lycophyte plant Selaginella lepidophylla (SelPAO5), together with the CrACL5 thermospermine synthase, converted almost all thermospermine to norspermidine. Although CrACL5 was efficient at aminopropylating norspermidine to form tetraamine norspermine, SelPAO5 oxidizes norspermine back to norspermidine, with the balance of flux being inclined fully to norspermine oxidation. The steady-state polyamine content of E. coli co-expressing thermospermine synthase CrACL5 and polyamine oxidase SelPAO5 was an almost total replacement of spermidine by norspermidine. We have recapitulated a potential hybrid biosynthetic-catabolic pathway for norspermidine production in E. coli, which could explain norspermidine accumulation in species that do not encode the known aspartate ß-semialdehyde-dependent pathway.
Assuntos
Espermidina , Espermidina/metabolismo , Espermidina/análogos & derivados , Espermidina/biossíntese , Chlamydomonas reinhardtii/metabolismo , Chlamydomonas reinhardtii/genética , Vias Biossintéticas , Escherichia coli/metabolismo , Escherichia coli/genética , Espermina/metabolismo , Espermina/análogos & derivadosRESUMO
Thevetia thevetioides is a species within the Apocynaceae family known for containing cardenolide-glycosides, commonly referred to as cardiac glycosides, which are characteristic of this genus. The seeds of the Thevetia species are frequently used as a model source for studying cardiac steroids, as these glycosides can be more readily extracted from the oil-rich seeds than from the plant's green tissues. In this work, the cardenolide profile of ripe and immature seeds was determined and compared to establish the main differences. Ripe seeds contain six related cardenolides and triosides, with thevetin B being the predominant component. In contrast, immature seeds exhibit a total of thirteen cardiac glycosides, including monoglycosides such as neriifolin and peruvosides A, B, and C, as well as diglycosides like thevebiosides A, B, and C. Some of these compounds have previously been identified as degradation products of more complex cardiac glycosides; however, their presence in immature seeds, as described in this study, suggests that they may serve as biosynthetic precursors to the triosides observed in mature seeds. The glycoside patterns observed via HPTLC are associated with specific chemical structures characteristic of this genus, typically featuring thevetose or acetyl-thevetose at the first position, followed by glucose or gentibiose in di- or trisaccharides, independent of the trioside aglycones identified: digitoxigenin, cannogenin, or yccotligenin. Ripe seeds predominantly contain triosides, including thevetin B, C, and A, the latter of which has not been previously reported.
Assuntos
Cardenolídeos , Glicosídeos Cardíacos , Sementes , Espectrometria de Massas em Tandem , Sementes/química , Sementes/metabolismo , Cardenolídeos/metabolismo , Cardenolídeos/química , Glicosídeos Cardíacos/química , Glicosídeos Cardíacos/metabolismo , Espectrometria de Massas em Tandem/métodos , Cromatografia em Camada Fina/métodos , Vias Biossintéticas , Apocynaceae/química , Apocynaceae/metabolismoRESUMO
This study explores the organization, conservation, and diversity of biosynthetic gene clusters (BGCs) among Bacillus sp. strain BH32, a plant-beneficial bacterial endophyte, and its closest nontype Bacillus cereus group strains. BGC profiles were predicted for each of the 17 selected strains using antiSMASH, resulting in the detection of a total of 198 BGCs. We quantitatively compared the BGCs and analysed their conservation, distribution, and evolutionary relationships. The study identified both conserved and singleton BGCs across the studied Bacillus strains, with minimal variation, and discovered two major BGC synteny blocks composed of homologous BGCs conserved within the B. cereus group. The identified BGC synteny blocks provide insight into the evolutionary relationships and diversity of BGCs within this complex group.