Sorangipyranone was isolated as a novel natural product featuring a unique 2,3-dihydro-γ-4H-pyrone scaffold from cultures of the myxobacterial strain MSr12020. We report here the full structure ...elucidation of sorangipyranone by spectroscopic techniques including 2D NMR and high-resolution mass spectrometry together with the analysis of the biosynthetic pathway. Determination of the absolute configuration was performed by TDDFT-ECD calculations and determination of the applicability of the Snatzke's helicity rule, to correlate the high-wavelength n→π* ECD transition and the absolute configuration of the 2,3-dihydro-4H-γ-pyrone, was done by the analysis of low-energy conformers and the Kohn-Sham orbitals. Sorangipyranone outlines a new class of a γ-dihydropyrone-containing natural product comprised of malonyl-CoA-derived building blocks and features a unique polyketide scaffold. In silico analysis of the genome sequence of the myxobacterial strain MSr12020 complemented with feeding experiments employing stable isotope-labeled precursors allowed the identification and annotation of a candidate biosynthetic gene cluster which encodes a modular polyketide synthase assembly line. A model for the biosynthetic pathway leading to the formation of the γ-dihydropyrone scaffold is presented in this study.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
spp. are common soil-dwelling organisms which kill and consume prey microbes through the secretion of antimicrobial substances. Two species of
have been described previously (
and
). A polyphasic ...approach, including biochemical analysis of fatty acid methyl esters, substrate utilization, and sugar assimilation assays, was taken to characterize eight
species strains and the two type strains. The genomes of all strains, including that of
DSM 14696
(newly reported here), shared an average nucleotide identity below 95% and digital DNA-DNA hybridization scores of less than 70%, indicating that they belong to distinct species. In addition, we characterized the prey range and antibiotic resistance profile of each strain, illustrating the diversity of antimicrobial activity and, thus, the potential for drug discovery within the
genus. Each strain gave a distinct profile of properties, which together with their genomic differences supports the proposal of the eight candidate strains as novel species. The eight candidates are as follows:
sp. nov. (AB043A
DSM 108849
= NBRC 113887
),
sp. nov. (AB047A
DSM 108843
= NBRC 113888
),
sp. nov. (AB050A
= DSM 108846
= NBRC 114019
),
sp. nov. (CA031B
DSM 108841
= NBRC 113889
),
sp. nov. (CA040B
DSM 108850
= NBRC 113890
),
sp. nov. (CA043D
DSM 108842
= NBRC 113891
),
sp. nov. (CA051B
DSM 108844
= NBRC 114100
), and
sp. nov. (CA054A
DSM 108848
= NBRC 113892
).
is a genus of predators with broad prey ranges, whose genomes contain large numbers of gene clusters for secondary metabolite biosynthesis. The physiology and evolutionary heritage of eight
species strains were characterized using a range of analyses and assays. Multiple metrics confirmed that each strain belonged to a novel species within the
genus. The strains exhibited distinct patterns of drug resistance and predatory activity, which mirrored their possession of diverse sets of biosynthetic genes. The breadth of antimicrobial activities observed within the
genus highlights their potential for drug discovery and suggests a previous underestimation of both their taxonomic diversity and biotechnological potential. Taxonomic assignment of environmental isolates to novel species allows us to begin to characterize the diversity and evolution of members of this bacterial genus with potential biotechnological importance, guiding future bioprospecting efforts for novel biologically active metabolites and antimicrobials.
Myxobacteria are part of the phylum Myxococcota, encompassing four orders. Most of them display complex lifestyles and broad predation profiles. However, metabolic potential and predation mechanisms ...of different myxobacteria remains poorly understood. Herein, we used comparative genomics and transcriptomics to analyze metabolic potentials and differentially expressed gene (DEG) profiles of
monoculture (Mx) compared to coculture with
(MxE) and
(MxM) prey. The results showed that myxobacteria had conspicuous metabolic deficiencies, various protein secretion systems (PSSs) and the common type II secretion system (T2SS). RNA-seq data demonstrated that
overexpressed the potential predation DEGs, particularly those encoding T2SS, the tight adherence (Tad) pilus, different secondary metabolites (myxochelin A/B, myxoprincomide, myxovirescin A1, geosmin and myxalamide), glycosyl transferases and peptidase during predation. Furthermore, the myxalamide biosynthesis gene clusters, two hypothetical gene clusters and one arginine biosynthesis clusters were highly differential expressed in MxE versus MxM. Additionally, homologue proteins of the Tad (kil) system and five secondary metabolites were in different obligate or facultative predators. Finally, we provided a working model for exhibiting multiple predatory strategies when
prey on
and
. These results might spur application-oriented research on the development of novel antibacterial strategies.
DKxanthenes are a class of yellow secondary metabolites produced by myxobacterial genera Myxococcus and Stigmatella. We identified a putative 49.5 kb DKxanthene biosynthetic gene cluster from ...Myxococcus stipitatus DSM 14675 by genomic sequence and mutational analyses.
The cluster consisted of 15 genes (MYSTI_06004-MYSTI_06018) encoding polyketide synthases, non-ribosomal peptide synthases, and proteins with unknown functions. Disruption of the genes by plasmid insertion resulted in defects in the production of yellow pigments. Highperformance liquid chromatography and liquid chromatography-tandem mass spectrometry analyses indicated that the yellow pigments produced by M. stipitatus DSM 14675 might be novel DKxanthene derivatives. M. stipitatus did not require DKxanthenes for the formation of heat-resistant viable spores, unlike Myxococcus xanthus. Furthermore, DKxanthenes showed growth inhibitory activity against the fungi Aspergillus niger, Candida albicans, and Rhizopus stolonifer. KCI Citation Count: 0
Chemical exchanges between plants and microbes within rhizobiomes are critical to the development of community structure. Volatile root exudates such as the phytohormone methyljasmonate (MeJA) ...contribute to various plant stress responses and have been implicated to play a role in the maintenance of microbial communities. Myxobacteria are competent predators of plant pathogens and are generally considered beneficial to rhizobiomes. While plant recruitment of myxobacteria to stave off pathogens has been suggested, no involved chemical signaling processes are known. Herein we expose predatory myxobacteria to MeJA and employ untargeted mass spectrometry, motility assays, and RNA sequencing to monitor changes in features associated with predation such as specialized metabolism, swarm expansion, and production of lytic enzymes. From a panel of four myxobacteria, we observe the most robust metabolic response from plant-associated
sp. strain Cb G35 with 10 μM MeJA impacting the production of at least 300 metabolites and inducing a ≥ fourfold change in transcription for 56 genes. We also observe that MeJA induces
sp. motility supporting plant recruitment of a subset of the investigated micropredators. Provided the varying responses to MeJA exposure, our observations indicate that MeJA contributes to the recruitment of select predatory myxobacteria suggesting further efforts are required to explore the microbial impact of plant exudates associated with biotic stress.
A non-fruiting group of myxobacteria was previously speculated to exist in nature based on metagenomics data containing uncultured members of the order Myxococcales. Here, we describe a myxobacterial ...strain, designated MCy10636
, which was isolated from a German soil sample collected in 2013. It exhibits swarming characteristics but atypically produces myxospores in the absence of fruiting bodies. The novel strain stains Gram-negative and Congo-red-negative and is characterized mesophilic, neutrophilic, chemoheterotrophic and microaerotolerant. Branched-chain fatty acids are the predominant cellular fatty acids over the straight-chain type, and contain the major fatty acids iso-C17 : 0 2-OH, C16 : 1, iso-C17 : 0 and iso-C15 : 0. Based on blastn results, the 16S rRNA gene sequence reveals similarity (97 %) to Aggregicoccus edonensis MCy1366
, (97 %) Myxococcus macrosporus DSM 14697
, (96 %) Corallococcus coralloides DSM2259
and Corallococcus exiguus Cc e167
. Phylogenetic analysis showed a novel lineage of MCy10636
in the family Myxococcaceae, suborder Cystobacterineae. Based on polyphasic taxonomic characterization, we propose that this unusual, non-fruiting, myxospore-forming and microaerotolerant myxobacterial strain, MCy10636
, represents a novel genus and species, Simulacricoccus ruber gen. nov., sp. nov. (DSM 106554
=NCCB 100651
).
Bacterial predators are widely distributed across a variety of natural environments. Understanding predatory interactions is of great importance since they play a defining role in shaping microbial ...communities in habitats such as soils.
is a soil-dwelling bacterial predator that can prey on Gram-positive and Gram-negative bacteria and even on eukaryotic microorganisms. This model organism has been studied for many decades for its unusual lifecycle, characterized by the formation of multicellular fruiting bodies filled with myxospores. However, less is known about its predatory behavior despite being an integral part of its lifecycle. Predation in
is a multifactorial process that involves several mechanisms working synergistically, including motility systems to efficiently track and hunt prey, and a combination of short-range and contact-dependent mechanisms to achieve prey death and feed on them. In the short-range attack,
is best known for the collective production of secondary metabolites and hydrolytic enzymes to kill prey and degrade cellular components. On the other hand, contact-dependent killing is a cell-to-cell process that relies on Tad-like and type III secretion systems. Furthermore, recent research has revealed that metals also play an important role during predation, either by inducing oxidative stress in the prey, or by competing for essential metals. In this paper, we review the current knowledge about
predation, focusing on the different mechanisms used to hunt, kill, and feed on its prey, considering the most recent discoveries and the transcriptomic data available.
The family of anti‐fungal natural products known as the ambruticins are structurally distinguished by a pair of pyran rings adorning a divinylcyclopropane core. Previous characterization of their ...biosynthesis, including the expression of a genetically modified producing organism, revealed that the polyketide synthase pathway proceeds via a diol intermediate, known as ambruticin J. Herein, we report the first enantioselective total synthesis of the putative PKS product, ambruticin J, according to a triply convergent synthetic route featuring a Suzuki‐Miyaura cross‐coupling and a Julia‐Kocienski olefination for fragment assembly. This synthesis takes advantage of synthetic methodology previously developed by our laboratory for the stereoselective generation of the trisubstituted cyclopropyl linchpin.
First total synthesis: A putative intermediate in ambruticin biosynthesis was prepared by a convergent route using a trisubstituted cyclopropyl linchpin. The stereochemical assignment has been confirmed and incorrect spectral data have been updated. Access to this material will enable studies of the post‐PKS processing that leads to ambruticin structures and aid greater understanding of their potent anti‐fungal activity.
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