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Folia Microbiologica Feb 2024Secondary metabolites produced by myxobacterial genera are often characterized as diverse molecules with unique structural properties which drove us to search for...
Secondary metabolites produced by myxobacterial genera are often characterized as diverse molecules with unique structural properties which drove us to search for myxobacterial source of anti-diabetic drug discovery. In the present study, from 80 soil samples, out of sixty-five observed isolates, 30 and 16 were purified as Myxococcus and non-Myxococcus, respectively. Isolated strains taxonomically belonged to the genera Myxococcus, Corallococcus and Cystobacter, Archangium, Nanocystis, and Sorangium, and some could not be attributed. Secondary metabolites of selected non-Myxococcus isolates extracted by the liquid-liquid method showed that the myxobacterium UTMC 4530 demonstrated the highest inhibition on the formation of carbonyl group and fructosamine, respectively. In addition, it showed 23% and 15.8% inhibitory activity on α-glucosides and α-amylase compared to acarbose (23%, 18%), respectively. The extract of strain UTMC 4530 showed 35% induction effect on glucose adsorption while showing no radical scavenging activity and no toxic effect on HRBC lysis and HepG2 in cytotoxicity assays. The strain UTMC 4530 (ON808962), with the multiple antidiabetic activity, showed 87.3% similarity to Corallococcus llansteffanensis which indicates its affiliation to a new genus. The results of this study revealed that secondary metabolites produced by strain UTMC 4530 can be considered a promising source to find new therapeutic and pharmaceutical applications perhaps a multi-mechanism anti-diabetic compound.
Topics: Myxococcales; Soil Microbiology; Soil; Phylogeny; Myxococcus
PubMed: 37477787
DOI: 10.1007/s12223-023-01074-8 -
Journal of the American Chemical Society Aug 2023The genomes of myxobacteria harbor a variety of biosynthetic gene clusters encoding numerous secondary metabolites, including ribosomally synthesized and...
The genomes of myxobacteria harbor a variety of biosynthetic gene clusters encoding numerous secondary metabolites, including ribosomally synthesized and post-translationally modified peptides (RiPPs) with diverse chemical structures and biological activities. However, the biosynthetic potential of RiPPs from myxobacteria remains barely explored. Herein, we report a novel myxobacteria lanthipeptide myxococin identified from . Myxococins represent the first example of lanthipeptides, of which the characteristic multiple thioether rings are installed by employing a Class II lanthipeptide synthetase MfuM and a Class I lanthipeptide cyclase MfuC in a cascaded way. Unprecedentedly, we biochemically characterized the first M61 family aminopeptidase MfuP involved in RiPP biosynthesis, demonstrating that MfuP showed the activity of an endopeptidase activity. MfuP is leader-independent but strictly selective for the multibridge structure of myxococin A and responsible for unwrapping two rings via amide bond hydrolysis, yielding myxococin B. Furthermore, the X-ray crystal structure of MfuP and structural analysis, including active-site mutations, are reported. Finally, myxococins are evaluated to exhibit anti-inflammatory activity in lipopolysaccharide-induced macrophages without detectable cytotoxicity.
Topics: Myxococcales; Peptides; Protein Processing, Post-Translational
PubMed: 37466996
DOI: 10.1021/jacs.3c06014 -
Bio-protocol Jul 2023In the environment, bacteria compete for niche occupancy and resources; they have, therefore, evolved a broad variety of antibacterial weapons to destroy competitors....
In the environment, bacteria compete for niche occupancy and resources; they have, therefore, evolved a broad variety of antibacterial weapons to destroy competitors. Current laboratory techniques to evaluate antibacterial activity are usually labor intensive, low throughput, costly, and time consuming. Typical assays rely on the outgrowth of colonies of prey cells on selective solid media after competition. Here, we present fast, inexpensive, and complementary optimized protocols to qualitatively and quantitively measure antibacterial activity. The first method is based on the degradation of a cell-impermeable chromogenic substrate of the β-galactosidase, a cytoplasmic enzyme released during lysis of the attacked reporter strain. The second method relies on the lag time required for the attacked cells to reach a defined optical density after the competition, which is directly dependent on the initial number of surviving cells. Key features First method utilizes the release of β-galactosidase as a proxy for bacterial lysis. Second method is based on the growth timing of surviving cells. Combination of two methods discriminates between cell death and lysis, cell death without lysis, or survival to quasi-lysis. Methods optimized to various bacterial species such as , and . Graphical overview.
PubMed: 37449039
DOI: 10.21769/BioProtoc.4706 -
Nature Communications Jul 2023During cell migration, front-rear polarity is spatiotemporally regulated; however, the underlying design of regulatory interactions varies. In rod-shaped Myxococcus...
During cell migration, front-rear polarity is spatiotemporally regulated; however, the underlying design of regulatory interactions varies. In rod-shaped Myxococcus xanthus cells, a spatial toggle switch dynamically regulates front-rear polarity. The polarity module establishes front-rear polarity by guaranteeing front pole-localization of the small GTPase MglA. Conversely, the Frz chemosensory system, by acting on the polarity module, causes polarity inversions. MglA localization depends on the RomR/RomX GEF and MglB/RomY GAP complexes that localize asymmetrically to the poles by unknown mechanisms. Here, we show that RomR and the MglB and MglC roadblock domain proteins generate a positive feedback by forming a RomR/MglC/MglB complex, thereby establishing the rear pole with high GAP activity that is non-permissive to MglA. MglA at the front engages in negative feedback that breaks the RomR/MglC/MglB positive feedback allosterically, thus ensuring low GAP activity at this pole. These findings unravel the design principles of a system for switchable front-rear polarity.
Topics: Myxococcus xanthus; Bacterial Proteins; Cell Movement; Monomeric GTP-Binding Proteins; Cell Polarity
PubMed: 37422455
DOI: 10.1038/s41467-023-39773-y -
IScience Jul 2023Many microbial phenotypes are density-dependent, including group-level phenotypes emerging from cooperation. However, surveys for the presence of a particular form of...
Many microbial phenotypes are density-dependent, including group-level phenotypes emerging from cooperation. However, surveys for the presence of a particular form of density dependence across diverse species are rare, as are direct tests for the Allee effect, i.e., positive density dependence of fitness. Here, we test for density-dependent growth under acid stress in five diverse bacterial species and find the Allee effect in all. Yet social protection from acid stress appears to have evolved by multiple mechanisms. In a strong Allee effect is mediated by pH-regulated secretion of a diffusible molecule by high-density populations. In other species, growth from low density under acid stress was not enhanced by high-density supernatant. In , high cell density may promote predation on other microbes that metabolically acidify their environment, and acid-mediated density dependence may impact the evolution of fruiting-body development. More broadly, high density may protect most bacterial species against acid stress.
PubMed: 37332671
DOI: 10.1016/j.isci.2023.106952 -
Microbiology Spectrum Aug 2023Myxobacteria serve as a treasure trove of secondary metabolites. During our ongoing search for bioactive natural products, a novel subclass of disorazoles termed...
Myxobacteria serve as a treasure trove of secondary metabolites. During our ongoing search for bioactive natural products, a novel subclass of disorazoles termed disorazole Z was discovered. Ten disorazole Z family members were purified from a large-scale fermentation of the myxobacterium Sorangium cellulosum So ce1875 and characterized by electrospray ionization-high-resolution mass spectrometry (ESI-HRMS), X-ray, nuclear magnetic resonance (NMR), and Mosher ester analysis. Disorazole Z compounds are characterized by the lack of one polyketide extension cycle, resulting in a shortened monomer in comparison to disorazole A, which finally forms a dimer in the bis-lactone core structure. In addition, an unprecedented modification of a geminal dimethyl group takes place to form a carboxylic acid methyl ester. The main component disorazole Z1 shows comparable activity in effectively killing cancer cells to disorazole A1 via binding to tubulin, which we show induces microtubule depolymerization, endoplasmic reticulum delocalization, and eventually apoptosis. The disorazole Z biosynthetic gene cluster (BGC) was identified and characterized from the alternative producer So ce427 and compared to the known disorazole A BGC, followed by heterologous expression in the host Myxococcus xanthus DK1622. Pathway engineering by promoter substitution and gene deletion paves the way for detailed biosynthesis studies and efficient heterologous production of disorazole Z congeners. Microbial secondary metabolites are a prolific reservoir for the discovery of bioactive compounds, which prove to be privileged scaffolds for the development of new drugs such as antibacterial and small-molecule anticancer drugs. Consequently, the continuous discovery of novel bioactive natural products is of great importance for pharmaceutical research. Myxobacteria, especially spp., which are known for their large genomes with yet-underexploited biosynthetic potential, are proficient producers of such secondary metabolites. From the fermentation broth of Sorangium cellulosum strain So ce1875, we isolated and characterized a family of natural products named disorazole Z, which showed potent anticancer activity. Further, we report on the biosynthesis and heterologous production of disorazole Z. These results can be stepping stones toward pharmaceutical development of the disorazole family of anticancer natural products for (pre)clinical studies.
Topics: Biological Products; Antineoplastic Agents; Lactones; Myxococcales
PubMed: 37318329
DOI: 10.1128/spectrum.00730-23 -
Applied Microbiology and Biotechnology Aug 2023In our previous work, a recombinant aflatoxin-degrading enzyme derived from Myxococcus fulvus (MADE) was reported. However, the low thermal stability of the enzyme had...
In our previous work, a recombinant aflatoxin-degrading enzyme derived from Myxococcus fulvus (MADE) was reported. However, the low thermal stability of the enzyme had limitations for its use in industrial applications. In this study, we obtained an improved variant of recombinant MADE (rMADE) with enhanced thermostability and catalytic activity using error-prone PCR. Firstly, we constructed a mutant library containing over 5000 individual mutants. Three mutants with T values higher than the wild-type rMADE by 16.5 °C (rMADE-1124), 6.5 °C (rMADE-1795), and 9.8 °C (rMADE-2848) were screened by a high-throughput screening method. Additionally, the catalytic activity of rMADE-1795 and rMADE-2848 was improved by 81.5% and 67.7%, respectively, compared to the wild-type. Moreover, structural analysis revealed that replacement of acidic amino acids with basic amino acids by a mutation (D114H) in rMADE-2848 increased the polar interactions with surrounding residues and resulted in a threefold increase in the t value of the enzyme and made it more thermaltolerate. KEY POINTS: • Mutant libraries construction of a new aflatoxins degrading enzyme by error-prone PCR. • D114H/N295D mutant improved enzyme activity and thermostability. • The first reported enhanced thermostability of aflatoxins degrading enzyme better for its application.
Topics: Aflatoxins; Enzyme Stability; Polymerase Chain Reaction; Mutation; Cloning, Molecular; Temperature
PubMed: 37300712
DOI: 10.1007/s00253-023-12610-4 -
Environmental Pollution (Barking, Essex... Aug 2023The potential of sulphur (S), MgSO (Mg), and KHPO (P) in nitrogen retention, ammonia emission decrease, and microbial community succession during composting needs to be...
The potential of sulphur (S), MgSO (Mg), and KHPO (P) in nitrogen retention, ammonia emission decrease, and microbial community succession during composting needs to be investigated. To achieve this, different levels of S (0, 0.2, 0.4, 0.6, and 0.8% in dry weight) plus Mg and P (S + Mg + P) were progressively added in 70 days pig manure aerobic composting. The results revealed that the amendment increased salinity and lowered pH and dephytotoxication of the product with the increase of S amount. However, no significant inhibition effects were observed on the evolution of the thermophilic phase and product maturity. In addition, the amendment significantly reduced the total NH and NO emissions by 29.66%-58.81% and 20.6%-56.7%, increased NH level by 17.22%-73.21% in thermophilic phase and NO content by 26.17%-57.48% in a mature phase, and elevated the total Kjeldahl nitrogen content by 34.28%-46.6% during the composting. In addition, compared to the control, the supplement markedly encouraged the formation of guanite in the compost product. The S addition stimulated the growth of Anseongella, Actinomadura, Chelativorans, Castellaniella, Luteimonas, and Steroidobacter microbial communities which functioned well in the degradation of nitrogen-containing compounds and organic matter. Evidence from Redundancy Analysis, Firmicutes, Myxococcus, Chloroflexi, Gemmatimonadota, and Deinococcota showed positive correlations with pH. These results imply that adding S-Mg-P amendment encourages the population and activity of specific functional microorganisms, and facilitated the ammonia emission reduction by lowering pH and thus reserved nitrogen through the formation of guanite during composting. The investigation of bacterial community abundance and environmental variables at the phylum and genus levels over time revealed that adding of 0.6% S in conjunction with P and Mg minerals was suitable for nitrogen loss mitigation in composting. The findings suggest using S + Mg + P supplement to conserve nitrogen in pig dung aerobic composting.
Topics: Swine; Animals; Ammonia; Manure; Composting; Soil; Nitrogen; Sulfur; Bacteria
PubMed: 37263560
DOI: 10.1016/j.envpol.2023.121934