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Inadequately managed solid organic waste generation poses a threat to the environment and human health globally. Biotransformation with the black soldier fly larvae (BSFL) is emerging as talent technology for solid waste management. However, there is a lack of understanding of whether BSFL can effectively suppress potential pathogenic microorganisms during management and the underlying mechanisms. In this study, we investigated the temporal variations of microorganisms in two common types of solid waste, i.e., kitchen waste (KW) and pig manure (PM). Natural composting and composting with BSFL under three different pH levels (pH 5, 7, and 9) were established to explore their impact on microbial communities in compost and the gut of BSFL. The results showed that the compost of kitchen waste and pig manure led to an increase in relative abundance of various potentially pathogenic bacteria. Temporal gradient analyses revealed that the most substantial reduction in the relative abundance and diversity of potentially pathogenic microorganisms occurred when the initial pH of both two wastes were adjusted to 7 upon the introduction of BSFL. Through network and pls-pm analysis, it was discovered that the gut microbiota of BSFL occupied an ecological niche in the compost, inhibiting the proliferation of potentially pathogenic microorganisms. This study has revealed the potential of BSFL in reducing public health risks during the solid waste management process, providing robust support for sustainable waste management.
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Compostaje , Dípteros , Humanos , Animales , Porcinos , Larva/fisiología , Residuos Sólidos , Estiércol , Dípteros/fisiologíaRESUMEN
Coronarin (COR), an analog of jasmonic acid, has been shown to enhance the tolerance of plants to drought. However, the effects of COR on the interactions among microorganisms associated with plant roots and their implications for enhancing the drought tolerance of plants remain unclear. Here, we studied the effects of applying COR on the microorganisms associated with plant roots and the rhizosphere metabolome. Treatment with COR affected the fungal community of the rhizosphere by inducing changes in the rhizosphere metabolome, which enhanced the drought tolerance of plants. However, treatment with COR had no significant effect on root microorganisms or rhizosphere bacteria. Specifically, the application of COR resulted in a significant reduction in the relative abundance of metabolites, such as mucic acid, 1,4-cyclohexanedione, 4-acetylbutyric acid, Ribonic acid, palmitic acid, and stearic acid, in maize roots under drought conditions; COR application also led to increases in the abundance of drought-resistant fungal microorganisms, including Rhizopus, and the assembly of a highly drought-resistant rhizosphere fungal network, which enhanced the drought tolerance of plants. Overall, the results of our study indicate that COR application positively regulates interactions between plants and microbes and increases the drought tolerance of plants.
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A novel GH2 (glycoside hydrolase family 2) ß-galactosidase from Marinomonas sp. BSi20584 was successfully expressed in E. coli with a stable soluble form. The recombinant enzyme (rMaBGA) was purified to electrophoretic homogeneity and characterized extensively. The specific activity of purified rMaBGA was determined as 96.827 U mg-1 at 30 °C using ONPG (o-nitrophenyl-ß-D-galactopyranoside) as a substrate. The optimum pH and temperature of rMaBGA was measured as 7.0 and 50 °C, respectively. The activity of rMaBGA was significantly enhanced by some divalent cations including Zn2+, Mg2+ and Ni2+, but inhibited by EDTA, suggesting that some divalent cations might play important roles in the catalytic process of rMaBGA. Although the enzyme was derived from a cold-adapted strain, it still showed considerable stability against various physical and chemical elements. Moreover, rMaBGA exhibited activity both toward Galß-(1,3)-GlcNAc and Galß-(1,4)-GlcNAc, which is a relatively rare occurrence in GH2 ß-galactosidase. The results showed that two domains in the C-terminal region might be contributed to the ß-1,3-galactosidase activity of rMaBGA. On account of its fine features, this enzyme is a promising candidate for the industrial application of ß-galactosidase.
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Galactosidasas , Glicósido Hidrolasas , Clonación Molecular , Cationes Bivalentes , Escherichia coli/genética , Escherichia coli/metabolismo , Especificidad por Sustrato , Temperatura , beta-Galactosidasa/química , Concentración de Iones de Hidrógeno , Estabilidad de Enzimas , CinéticaRESUMEN
BACKGROUND: Novel bone substitutes are urgently needed in experimental research and clinical orthopaedic applications. There are many traditional Chinese medicines that have effects on bone repair. However, application of natural medicines in traditional Chinese medicine to bone tissue engineering and its mechanism were rarely reported. RESULTS: In this study, the osteogenic ability of bioactive glass particles (BGPs) and the osteogenic and osteoclastic ability of neferine (Nef) were fused into PLGA-based bone tissue engineering materials for bone regeneration. BGPs were prepared by spray drying and calcination. Particles and Nef were then mixed with PLGA solution to prepare porous composites by the phase conversion method. Here we showed that Nef inhibited proliferation and enhanced ALP activity of MC3T3-E1 cells in a dose- and time-dependent manner. And the composites containing Nef could also inhibit RANKL-induced osteoclast formation (p < 0.05). Mechanistically, the PLGA/BGP/Nef composite downregulated the expression of NFATC1 by inhibiting the NF-κB pathway to restrain osteoclasts. In the other hands, PLGA/BGP/Nef composite was first demonstrated to effectively activate the IGF-1R/PI3K/AKT/mTOR pathway to enhance IGF-1-mediated osteogenic differentiation. The results of animal experiments show that the material can effectively promote the formation and maturation of new bone in the skull defect site. CONCLUSIONS: The PLGA/BGP/Nef porous composite can restrain osteoclasts by inhibiting the NF-κB pathway, enhance IGF-1-mediated osteogenic differentiation and promotes bone regeneration, and has the potential for clinical application.
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Prebiotics are compounds that selectively stimulate the growth and activity of beneficial microorganisms. The use of prebiotics is a well-established strategy for managing human gut health. This concept can also be extended to plants where plant rhizosphere microbiomes can improve the nutrient acquisition and disease resistance. However, we lack effective strategies for choosing metabolites to elicit the desired impacts on plant health. In this study, we target the rhizosphere of tomato (Solanum lycopersicum) suffering from wilt disease (caused by Ralstonia solanacearum) as source for potential prebiotic metabolites. We identify metabolites (ribose, lactic acid, xylose, mannose, maltose, gluconolactone, and ribitol) exclusively used by soil commensal bacteria (not positively correlated with R. solanacearum) but not efficiently used by the pathogen in vitro. Metabolites application in the soil with 1 µmol g-1 soil effectively protects tomato and other Solanaceae crops, pepper (Capsicum annuum) and eggplant (Solanum melongena), from pathogen invasion. After adding prebiotics, the rhizosphere soil microbiome exhibits enrichment of pathways related to carbon metabolism and autotoxin degradation, which were driven by commensal microbes. Collectively, we propose a novel pathway for mining metabolites from the rhizosphere soil and their use as prebiotics to help control soil-borne bacterial wilt diseases.
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Ralstonia solanacearum , Solanum lycopersicum , Solanum melongena , Humanos , Prebióticos , Rizosfera , Suelo , Enfermedades de las Plantas/prevención & control , Enfermedades de las Plantas/microbiología , Bacterias , Ralstonia solanacearum/metabolismoRESUMEN
With the gradual maturity of sequencing technology, many microbiome studies have published, driving the emergence and advance of related analysis tools. R language is the widely used platform for microbiome data analysis for powerful functions. However, tens of thousands of R packages and numerous similar analysis tools have brought major challenges for many researchers to explore microbiome data. How to choose suitable, efficient, convenient, and easy-to-learn tools from the numerous R packages has become a problem for many microbiome researchers. We have organized 324 common R packages for microbiome analysis and classified them according to application categories (diversity, difference, biomarker, correlation and network, functional prediction, and others), which could help researchers quickly find relevant R packages for microbiome analysis. Furthermore, we systematically sorted the integrated R packages (phyloseq, microbiome, MicrobiomeAnalystR, Animalcules, microeco, and amplicon) for microbiome analysis, and summarized the advantages and limitations, which will help researchers choose the appropriate tools. Finally, we thoroughly reviewed the R packages for microbiome analysis, summarized most of the common analysis content in the microbiome, and formed the most suitable pipeline for microbiome analysis. This paper is accompanied by hundreds of examples with 10,000 lines codes in GitHub, which can help beginners to learn, also help analysts compare and test different tools. This paper systematically sorts the application of R in microbiome, providing an important theoretical basis and practical reference for the development of better microbiome tools in the future. All the code is available at GitHub github.com/taowenmicro/EasyMicrobiomeR.
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Microbiota , Programas Informáticos , Análisis de Secuencia de ADN , LenguajeRESUMEN
The gut microbiome of plant-eaters is affected by the food they eat, but it is currently unclear how the plant metabolome and microbiome are influenced by the substrate the plant grows in and how this subsequently impacts the feeding behavior and gut microbiomes of insect herbivores. Here, we use Plutella xylostella caterpillars and show that the larvae prefer leaves of cabbage plants growing in a vermiculite substrate to those from plants growing in conventional soil systems. From a plant metabolomics analysis, we identified 20 plant metabolites that were related to caterpillar feeding performance. In a bioassay, the effects of these plant metabolites on insects' feeding were tested. Nitrate and compounds enriched with leaves of soilless cultivation promoted the feeding of insects, while compounds enriched with leaves of plants growing in natural soil decreased feeding. Several microbial groups (e.g., Sporolactobacillus, Haliangium) detected inside the plant correlated with caterpillar feeding performance and other microbial groups, such as Ramlibacter and Methylophilus, correlated with the gut microbiome. Our results highlight the role of growth substrates on the food metabolome and microbiome and on the feeding performance and the gut microbiome of plant feeders. It illustrates how belowground factors can influence the aboveground properties of plant-animal systems, which has important implications for plant growth and pest control.
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Herbivoria , Insectos , Animales , Larva , Conducta Alimentaria , Suelo , Hojas de la Planta/metabolismoRESUMEN
Sideromycins are a unique subset of siderophores comprising of a siderophore conjugated to an antimicrobial agent. The "Trojan horse" antibiotic albomycins are unique sideromycins consisting of a ferrichrome-type siderophore conjugated to a peptidyl nucleoside antibiotic. They exhibit potent antibacterial activities against many model bacteria and a number of clinical pathogens. Earlier studies have provided significant insight into the biosynthetic pathway of the peptidyl nucleoside moiety. We herein decipher the biosynthetic pathway of the ferrichrome-type siderophore in Streptomyces sp. ATCC 700974. Our genetic studies suggested that abmA, abmB, and abmQ are involved in the formation of the ferrichrome-type siderophore. Additionally, we performed biochemical studies to demonstrate that a flavin-dependent monooxygenase AbmB and an N-acyltransferase AbmA catalyze sequential modifications of L-ornithine to generate N5-acetyl-N5-hydroxyornithine. Three molecules of N5-acetyl-N5-hydroxyornithine are then assembled to generate the tripeptide ferrichrome through the action of a nonribosomal peptide synthetase AbmQ. Of special note, we found out that orf05026 and orf03299, two genes scattered elsewhere in the chromosome of Streptomyces sp. ATCC 700974, have functional redundancy for abmA and abmB, respectively. Interestingly, both orf05026 and orf03299 are situated within gene clusters encoding putative siderophores. In summary, this study provided new insight into the siderophore moiety of albomycin biosynthesis and shed light on the contingency of multiple siderophores in albomycin-producing Streptomyces sp. ATCC 700974.
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Sideróforos , Streptomyces , Sideróforos/metabolismo , Ferricromo/química , Ferricromo/metabolismo , Streptomyces/genética , Streptomyces/metabolismo , Vías Biosintéticas , Nucleósidos/metabolismo , Antibacterianos/metabolismoRESUMEN
In plant immunity, the mutually antagonistic hormones salicylic acid (SA) and jasmonic acid (JA) are implicated in resistance to biotrophic and necrotrophic pathogens, respectively. Promoters that can respond to both SA and JA signals are urgently needed to engineer plants with enhanced resistance to a broad spectrum of pathogens. However, few natural pathogen-inducible promoters are available for this purpose. To address this problem, we have developed a strategy to synthesize dual SA- and JA-responsive promoters by combining SA- and JA-responsive cis elements based on the interaction between their cognate trans-acting factors. The resulting promoters respond rapidly and strongly to both SA and Methyl Jasmonate (MeJA), as well as different types of phytopathogens. When such a synthetic promoter was used to control expression of an antimicrobial peptide, transgenic plants displayed enhanced resistance to a diverse range of biotrophic, necrotrophic, and hemi-biotrophic pathogens. A dual-inducible promoter responsive to the antagonistic signals auxin and cytokinin was generated in a similar manner, confirming that our strategy can be used for the design of other biotically or abiotically inducible systems.
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Reguladores del Crecimiento de las Plantas , Transducción de Señal , Reguladores del Crecimiento de las Plantas/metabolismo , Ácido Salicílico/farmacología , Ácido Salicílico/metabolismo , Plantas Modificadas Genéticamente/genética , Plantas Modificadas Genéticamente/metabolismo , HormonasRESUMEN
Lasalocid, a representative polyether ionophore, has been successfully applied in veterinary medicine and animal husbandry and also displays promising potential for cancer therapy. Nevertheless, the regulatory system governing lasalocid biosynthesis remains obscure. Here, we identified two conserved (lodR2 and lodR3) and one variable (lodR1, found only in Streptomyces sp. strain FXJ1.172) putative regulatory genes through a comparison of the lasalocid biosynthetic gene cluster (lod) from Streptomyces sp. FXJ1.172 with those (las and lsd) from Streptomyces lasalocidi. Gene disruption experiments demonstrated that both lodR1 and lodR3 positively regulate lasalocid biosynthesis in Streptomyces sp. FXJ1.172, while lodR2 plays a negative regulatory role. To unravel the regulatory mechanism, transcriptional analysis and electrophoretic mobility shift assays (EMSAs) along with footprinting experiments were performed. The results revealed that LodR1 and LodR2 could bind to the intergenic regions of lodR1-lodAB and lodR2-lodED, respectively, thereby repressing the transcription of the lodAB and lodED operons, respectively. The repression of lodAB-lodC by LodR1 likely boosts lasalocid biosynthesis. Furthermore, LodR2 and LodE constitute a repressor-activator system that senses changes in intracellular lasalocid concentrations and coordinates its biosynthesis. LodR3 could directly activate the transcription of key structural genes. Comparative and parallel functional analyses of the homologous genes in S. lasalocidi ATCC 31180T confirmed the conserved roles of lodR2, lodE, and lodR3 in controlling lasalocid biosynthesis. Intriguingly, the variable gene locus lodR1-lodC from Streptomyces sp. FXJ1.172 seems functionally conserved when introduced into S. lasalocidi ATCC 31180T. Overall, our findings demonstrate that lasalocid biosynthesis is tightly controlled by both conserved and variable regulators, providing valuable guidance for further improving lasalocid production. IMPORTANCE Compared to its elaborated biosynthetic pathway, the regulation of lasalocid biosynthesis remains obscure. Here, we characterize the roles of regulatory genes in lasalocid biosynthetic gene clusters of two distinct Streptomyces species and identify a conserved repressor-activator system, LodR2-LodE, which could sense changes in the concentration of lasalocid and coordinate its biosynthesis with self-resistance. Furthermore, in parallel, we verify that the regulatory system identified in a new Streptomyces isolate is valid in the industrial lasalocid producer and thus applicable for the construction of high-yield strains. These findings deepen our understanding of regulatory mechanisms involved in the production of polyether ionophores and provide novel clues for the rational design of industrial strains for scaled-up production.
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The widespread emergence of antibiotic-resistant bacteria highlights the urgent need for new antimicrobial agents. Albomycins are a group of naturally occurring sideromycins with a thionucleoside antibiotic conjugated to a ferrichrome-type siderophore. The siderophore moiety serves as a vehicle to deliver albomycins into bacterial cells via a "Trojan horse" strategy. Albomycins function as specific inhibitors of seryl-tRNA synthetases and exhibit potent antimicrobial activities against both Gram-negative and Gram-positive bacteria, including many clinical pathogens. These distinctive features make albomycins promising drug candidates for the treatment of various bacterial infections, especially those caused by multidrug-resistant pathogens. We herein summarize findings on the discovery and structure elucidation, mechanism of action, biosynthesis and immunity, and chemical synthesis of albomcyins, with special focus on recent advances in the biosynthesis and chemical synthesis over the past decade (2012-2022). A thorough understanding of the biosynthetic pathway provides the basis for pathway engineering and combinatorial biosynthesis to create new albomycin analogues. Chemical synthesis of natural congeners and their synthetic analogues will be useful for systematic structure-activity relationship (SAR) studies, and thereby assist the design of novel albomycin-derived antimicrobial agents.
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Compost-based organic fertilizers made from animal manures may contain high levels of antibiotic resistance genes (ARGs). However, the factors affecting the abundance and profile of ARGs in organic fertilizers remain unclear. We conducted a national-wide survey in China to investigate the effect of material type and composting process on ARG abundance in commercial organic fertilizers and quantified the contributions of bacterial composition and mobile genetic elements (MGEs) to the structuring of ARGs, using quantitative PCR and Illumina sequencing of 16S rRNA gene amplicons. The tetracycline, sulfonamide, aminoglycoside and macrolide resistance genes were present at high levels in all organic fertilizers. Seven ARGs that confer resistance to clinically important antibiotics, including three ß-lactam resistance genes, three quinolone resistance genes and the colistin resistance gene mcr-1, were detected in 8 - 50% the compost samples, whereas the vancomycin resistance gene vanC was not detected. Raw material type had a significant (p < 0.001) effect on the ARG abundance, with composts made from animal feces except some cattle feces generally having higher loads of ARGs than those from non-animal raw materials. Composting process type showed no significant (p > 0.05) effect on ARG abundance in the organic fertilizers. MGEs exerted a greater influence on ARG composition than bacterial community, suggesting a strong mobility of ARGs in the organic fertilizers. Our study highlights the need to manage the risk of ARG dissemination from agricultural wastes.
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Antibacterianos , Fertilizantes , Animales , Antibacterianos/farmacología , Bacterias , Bovinos , Farmacorresistencia Bacteriana/genética , Genes Bacterianos , Macrólidos , Estiércol/análisis , ARN Ribosómico 16S/genéticaRESUMEN
The network analysis has attracted increasing attention and interest from ecological academics, thus it is of great necessity to develop more convenient and powerful tools. For that reason, we have developed an R package, named "ggClusterNet," to complete and display the network analysis in an easier manner. In that package, ten network layout algorithms are designed to better display the modules of microbiome network (randomClusterG, PolygonClusterG, PolygonRrClusterG, ArtifCluster, randSNEClusterG, PolygonModsquareG, PolyRdmNotdCirG, model_Gephi.2, model_igraph, and model_maptree). For the convenience of the users, many functions related to microbial network analysis, such as corMicor(), net_properties(), node_properties(), ZiPiPlot(), random_Net_compate(), are integrated to complete the network mining. Furthermore, the pipeline function named network.2() and corBionetwork() are also added for the quick achievement of the network or bipartite network analysis as well as their in-depth mining. The ggClusterNet is publicly available via GitHub (https://github.com/taowenmicro/ggClusterNet/) or Gitee (https://gitee.com/wentaomicro/ggClusterNet) for users' access. A complete description of the usages can be found on the manuscript's GitHub page (https://github.com/taowenmicro/ggClusterNet/wiki).
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Plant roots are one of the major mediators that allocate carbon captured from the atmosphere to soils as rhizodeposits, including root exudates. Although rhizodeposition regulates both microbial activity and the biogeochemical cycling of nutrients, the effects of particular exudate species on soil carbon fluxes and key rhizosphere microorganisms remain unclear. By combining high-throughput sequencing, q-PCR, and NanoSIMS analyses, we characterized the bacterial community structure, quantified total bacteria depending on root exudate chemistry, and analyzed the consequences on the mobility of mineral-protected carbon. Using well-controlled incubation experiments, we showed that the three most abundant groups of root exudates (amino acids, carboxylic acids, and sugars) have contrasting effects on the release of dissolved organic carbon (DOC) and bioavailable Fe in an Ultisol through the disruption of organo-mineral associations and the alteration of bacterial communities, thus priming organic matter decomposition in the rhizosphere. High resolution (down to 50â¯nm) NanoSIMS images of mineral particles indicated that iron and silicon co-localized significantly more organic carbon following amino acid inputs than treatments without exudates or with carboxylic acids. The application of sugar strongly reduced microbial diversity without impacting soil carbon mobilization. Carboxylic acids increased the prevalence of Actinobacteria and facilitated carbon mobilization, whereas amino acid addition increased the abundances of Proteobacteria that prevented DOC release. In summary, root exudate functions are defined by their chemical composition that regulates bacterial community composition and, consequently, the biogeochemical cycling of carbon in the rhizosphere.
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Herbicide-resistance in weeds has become a serious threat to agriculture across the world. Thus, there is an urgent need for the discovery and development of herbicides with new modes of action. Thaxtomin phytotoxins are a group of nitrated diketopiperazines produced by potato common scab-causing phytopathogen Streptomyces scabies and other actinobacterial pathogens. They are generally considered to function as inhibitors of cellulose synthesis in plants, and thus have great potential to be used as natural herbicides. Generation of an overproducing strain is crucial for the scale-up production of thaxtomins and their wide use in agriculture. In the present study, we employed a stepwise strategy by combining heterologous expression, repressor deletion, activator overexpression, and optimization of fermentation media for high-level production of thaxtomins. The maximum yield of 728 mg/L thaxtomins was achieved with engineered Streptomyces albidoflavus J1074 strains in shake-flask cultures, and it was approximately 36-fold higher than S. albidoflavus J1074 carrying the unmodified cluster. Moreover, the yield of thaxtomins could reach 1973 mg/L when the engineered strain was cultivated in a small-scale stirred-tank bioreactor. This is the highest titer reported to date, representing a significant leap forward for the scale-up production of thaxtomins. Our study presents a robust, easy-to-use system that will be broadly useful for improving titers of bioactive compounds in many Streptomyces species.
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Ingeniería Metabólica , Streptomyces , Indoles , Piperazinas , Streptomyces/genéticaRESUMEN
ABSTRACT: Low bone mineral density (BMD) was significantly related to the fracture of distal radius. Serum brain-derived neurotrophic factor (BDNF) level was closely related to BMD in spine and osteoporotic fractures. In this study, we aimed to explore the association of BDNF polymorphisms (rs6265 and rs7124442) with BMD and the fracture of distal radius.This retrospective study included 152 patients with distal radius fractures and 148 healthy controls. BDNF polymorphisms were detected via TaqMan allelic discrimination assay. BMD was evaluated through X-ray. Difference in features between cases and controls were compared adopting Chi-square test or t test. The associations of BDNF polymorphisms with fracture risk of distal radius and BMD were assessed employing χ2 test and expressed by odd ratios (ORs) with 95% confidence intervals (95% CIs).BMD was significantly decreased in patients with the fracture of distal radius than in healthy controls. The polymorphism rs6265 significantly increased the risk of distal radius fracture (adjustment: GA: ORâ=â1.724, 95%CIâ=â1.003 -2.951, Pâ=â.049; GG: ORâ=â2.415, 95%CIâ=â1.0219 -3.674, Pâ=â.005). Moreover, rs6265 genotypes GA (ORâ=â4.326, 95%CIâ=â1.725 -11.896, Pâ=â.003) and GG (ORâ=â13.285, 95%CIâ=â3.659 -51.072, Pâ=â.001) significantly increased BMD reduction. However, BDNF polymorphism rs7124442 had no obvious correlation with BMD or fracture risk.BMD was associated with BDNF rs6265 polymorphism. BDNF polymorphism rs6265 could elevate the risk of osteoporosis and distal radius fracture.
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Enfermedades Óseas Metabólicas/complicaciones , Predisposición Genética a la Enfermedad , Fracturas Osteoporóticas/epidemiología , Fracturas del Radio/epidemiología , Absorciometría de Fotón , Pueblo Asiatico , Estudios de Casos y Controles , China/epidemiología , Femenino , Humanos , Persona de Mediana Edad , Fracturas Osteoporóticas/etiología , Fracturas Osteoporóticas/genética , Fracturas del Radio/etiología , Fracturas del Radio/genética , Estudios Retrospectivos , Factores de RiesgoRESUMEN
Precise control of microbial gene expression is crucial for synthetic biotechnological applications. This is particularly true for the bacterial genus Streptomyces, major producers of diverse natural products including many antibiotics. Although a plethora of genetic tools have been developed for Streptomyces, there is still an urgent need for effective gene induction systems. We herein created two novel cellobiose-inducible regulatory systems referred to as Cel-RS1 and Cel-RS2. The regulatory systems are based upon the well-characterized repressor/operator pair CebR/cebO from Streptomyces scabies and the well-defined constitutive kasO* promoter. Both Cel-RS1 and Cel-RS2 exhibit a high level of induced reporter activity and virtually no leaky expression in three model Streptomyces species, which are commonly used as surrogate hosts for expression of natural product biosynthetic gene clusters. Cel-RS2 has been proven successful for programmable control of gene expression and controllable production of specialized metabolites in multiple Streptomyces species. The strategy can be used to expand the toolkit of inducible regulatory systems that will be broadly applicable to various Streptomyces.
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Celobiosa/metabolismo , Regulación Bacteriana de la Expresión Génica , Microorganismos Modificados Genéticamente , Familia de Multigenes , Regiones Promotoras Genéticas , Streptomyces , Microorganismos Modificados Genéticamente/genética , Microorganismos Modificados Genéticamente/metabolismo , Streptomyces/genética , Streptomyces/metabolismoRESUMEN
Mureidomycins (MRDs), a group of unique uridyl-peptide antibiotics, exhibit antibacterial activity against the highly refractory pathogen Pseudomonas aeruginosa. Our previous study showed that the cryptic MRD biosynthetic gene cluster (BGC) mrd in Streptomyces roseosporus NRRL 15998 could not be activated by its endogenous regulator 02995 but activated by an exogenous activator SsaA from sansanmycin's BGC ssa of Streptomyces sp. strain SS. Here we report the molecular mechanism for this inexplicable regulation. EMSAs and footprinting experiments revealed that SsaA could directly bind to a 14-nt palindrome sequence of 5'-CTGRCNNNNGTCAG-3' within six promoter regions of mrd. Disruption of three representative target genes (SSGG-02981, SSGG-02987 and SSGG-02994) showed that the target genes directly controlled by SsaA were essential for MRD production. The regulatory function was further investigated by replacing six regions of SSGG-02995 with those of ssaA. Surprisingly, only the replacement of 343-450 nt fragment encoding the 115-150 amino acids (AA) of SsaA could activate MRD biosynthesis. Further bioinformatics analysis showed that the 115-150 AA situated between two conserved domains of SsaA. Our findings significantly demonstrate that constitutive expression of a homologous exogenous regulatory gene is an effective strategy to awaken cryptic biosynthetic pathways in Streptomyces.
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Antibacterianos/biosíntesis , Proteínas Bacterianas/metabolismo , Genes Reguladores , Streptomyces/metabolismo , Proteínas Bacterianas/genética , Regulación Bacteriana de la Expresión Génica , Familia de Multigenes , Nucleósidos/biosíntesis , Streptomyces/genética , Factores de TranscripciónRESUMEN
Herbicide-resistant weeds are a growing problem worldwide. Thaxtomin phytotoxins are a group of nitrated diketopiperazines produced by the potato common scab-causing pathogen Streptomyces scabies and other actinobacterial plant pathogens. They represent a unique class of microbial natural products with distinctive structural features and promising herbicidal activity. The biosynthesis of thaxtomins proceeds through multiple steps of unusual enzymatic reactions. Advances in understanding of thaxtomins biosynthetic machinery have provided the basis for precursor-directed biosynthesis, pathway refactoring, and one-pot biocombinatorial synthesis to generate thaxtomin analogues. We herein summarize recent findings on the biosynthesis of thaxtomins and highlight recent advances in the rational generation of novel thaxtomins for the development of potent herbicidal agents.
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Vías Biosintéticas , Herbicidas/metabolismo , Ingeniería Metabólica , Malezas , Solanum tuberosum/microbiología , StreptomycesRESUMEN
Antimicrobial resistance is a major threat for public health worldwide. Novel antimicrobial drugs are urgently needed to combat the growing prevalence of antimicrobial resistance. Nucleoside antibiotics represent a unique class of microbial natural products with distinctive structural features and diverse biological activities. We herein summarize recent findings on the biosynthesis of representative nucleoside antibiotics, and highlight recent advances in the discovery and rational generation of nucleoside antibiotics for the development of novel antimicrobial agents.