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Bioscience, Biotechnology, and... Feb 2007The complex morphogenesis of the bacterial genus Streptomyces has made this genus a model prokaryote for study of multicellular differentiation, and its ability to... (Review)
Review
The complex morphogenesis of the bacterial genus Streptomyces has made this genus a model prokaryote for study of multicellular differentiation, and its ability to produce a wide variety of secondary metabolites has made it an excellent supplier of biologically active substances, including antibiotics. This review summarizes our study of these two characteristics of Streptomyces, focusing on the A-factor regulatory cascade and work derived from the A-factor study. A microbial hormone, A-factor (2-isocapryloyl-3R-hydroxymethyl-gamma-butyrolactone), triggers morphological differentiation and secondary metabolism in Streptomyces griseus. The key steps in the A-factor regulatory cascade, including afsA, encoding the key enzyme for A-factor biosynthesis, arpA, encoding the A-factor receptor, and adpA, encoding a transcriptional activator, are elucidated. The target genes of the regulatory cascade include genes of various functions required for morphological development and secondary metabolite formation. The biosynthesis gene clusters for grixazone and hexahydroxyperylenequinone are examples. The former contains the enzymes for novel benzene ring formation and phenoxazinone formation, and the latter contains enzymes belonging to a type III polyketide synthase and a cytochrome P-450. Enzymes of various catalytic functions in Streptomyces are useful as members of an artificial gene cluster constructed in Escherichia coli for fermentative production of plant-specific flavonoids, including isoflavones and unnatural compounds.
Topics: Anti-Bacterial Agents; Catalysis; Combinatorial Chemistry Techniques; DNA, Bacterial; Gene Expression Regulation, Bacterial; Models, Molecular; Streptomyces
PubMed: 17284841
DOI: 10.1271/bbb.60627 -
Microbiological Research Aug 2020The emergence of resistance among fungal phytopathogens poses a biggest threat across the world. Streptomyces are a group of spore-forming Gram + ve bacteria and...
The emergence of resistance among fungal phytopathogens poses a biggest threat across the world. Streptomyces are a group of spore-forming Gram + ve bacteria and prolific producers of secondary bioactive metabolites which have been used as biocontrol agents against phytopathogens and also known for plant growth promotion. The current study identified a potent isolate M4 from soil with broad spectrum antifungal activity against different fungal phytopathogens. The isolate was identified as a Streptomyces sp. on the basis of cultural, morphological, physiological, biochemical and phylogenetic characteristics. 16S rRNA gene sequence of M4 showed 100 % similarity with three Streptomyces spp. i.e. Streptomyces plicatus NBRC 13071 T (AB184291), Streptomyces rochei NBRC 12908 T AB184237 and Streptomyces enissocaesilis NRRL-B-16365 T (DQ026641). However, phenotypic and phylogenetic analysis concluded that M4 represents a novel sp. within the genus Streptomyces. One of the two antifungal compounds purified from Streptomyces M4 was identified as salvianolic acid B. To our knowledge, the present study is the first work reporting purification and characterization of salvianolic acid B from Streptomyces and its broad spectrum antifungal activity against different fungal phytopathogens viz. Alternaria spp., Fusarium spp., Colletotrichum spp., Cladosporium herbarum and Botrytis cineria. Salvianolic acid B was found to be photostable, thermostable (up to 70 °C) and non-mutagenic in nature and might be developed as safe biofungicide to control phytopathogens.
Topics: Alternaria; Antifungal Agents; Benzofurans; Biological Control Agents; Botrytis; Cladosporium; Colletotrichum; Fungi; Fusarium; Genes, Bacterial; Phylogeny; Plant Diseases; RNA, Ribosomal, 16S; Streptomyces
PubMed: 32361340
DOI: 10.1016/j.micres.2020.126478 -
Microbiology and Molecular Biology... Mar 2013Streptomycetes are the most abundant source of antibiotics. Typically, each species produces several antibiotics, with the profile being species specific. Streptomyces... (Review)
Review
Streptomycetes are the most abundant source of antibiotics. Typically, each species produces several antibiotics, with the profile being species specific. Streptomyces coelicolor, the model species, produces at least five different antibiotics. We review the regulation of antibiotic biosynthesis in S. coelicolor and other, nonmodel streptomycetes in the light of recent studies. The biosynthesis of each antibiotic is specified by a large gene cluster, usually including regulatory genes (cluster-situated regulators [CSRs]). These are the main point of connection with a plethora of generally conserved regulatory systems that monitor the organism's physiology, developmental state, population density, and environment to determine the onset and level of production of each antibiotic. Some CSRs may also be sensitive to the levels of different kinds of ligands, including products of the pathway itself, products of other antibiotic pathways in the same organism, and specialized regulatory small molecules such as gamma-butyrolactones. These interactions can result in self-reinforcing feed-forward circuitry and complex cross talk between pathways. The physiological signals and regulatory mechanisms may be of practical importance for the activation of the many cryptic secondary metabolic gene cluster pathways revealed by recent sequencing of numerous Streptomyces genomes.
Topics: Amino Acid Sequence; Anti-Bacterial Agents; Bacterial Proteins; Gene Expression Regulation, Bacterial; Humans; Molecular Sequence Data; Multigene Family; Signal Transduction; Streptomyces; Streptomyces coelicolor
PubMed: 23471619
DOI: 10.1128/MMBR.00054-12 -
Scientific Reports Sep 2016The genus Streptomyces is a widespread genus within the phylum Actinobacteria and has been isolated from various environments worldwide. However, little is known about...
The genus Streptomyces is a widespread genus within the phylum Actinobacteria and has been isolated from various environments worldwide. However, little is known about whether biogeography affects distributional pattern of Streptomyces in salty environments. Such information is essential for understanding the ecology of Streptomyces. Here we analyzed four house-keeping genes (16S rRNA, rpoB, recA and atpD) and salty-tolerance related genes (ectA-ectD) of 38 Streptomyces strains isolated from saline environments in Yunnan and Xinjiang Provinces of western China. The obtained Streptomyces strains were classified into three operational taxonomic units, each comprising habitat-specific geno- and ecotype STs. In combination with expressional variations of salty-tolerance related genes, the statistical analyses showed that spatial distance and environmental factors substantially influenced Streptomyces distribution in saline environments: the former had stronger influence at large spatial scales (>700 km), whereas the latter was influential at large (>700 km) and small spatial scales (<700 km). Plus, the quantitative analyses of salty-tolerence related genes (ectA-D) indicated that Streptomyces strains from salt lakes have higher expression of ectA-D genes and could accumulate larger quantities of ectoine and hydroxyectoine than strains from salt mines, which could help them resist to salinity in the hypersaline environments.
Topics: Biological Evolution; China; Ecosystem; Genes, Bacterial; Phylogeography; Salt Tolerance; Streptomyces
PubMed: 27596681
DOI: 10.1038/srep32718 -
FEMS Microbiology Letters May 2013Streptomycetes comprise very important industrial bacteria, producing two-thirds of all clinically relevant secondary metabolites. They are mycelial microorganisms with... (Review)
Review
Streptomycetes comprise very important industrial bacteria, producing two-thirds of all clinically relevant secondary metabolites. They are mycelial microorganisms with complex developmental cycles that include programmed cell death (PCD) and sporulation. Industrial fermentations are usually performed in liquid cultures (large bioreactors), conditions in which Streptomyces strains generally do not sporulate, and it was traditionally assumed that there was no differentiation. In this work, we review the current knowledge on Streptomyces pre-sporulation stages of Streptomyces differentiation.
Topics: Models, Biological; Spores, Bacterial; Streptomyces
PubMed: 23496097
DOI: 10.1111/1574-6968.12128 -
BMC Microbiology Feb 2020Production of antibiotics to inhibit competitors affects soil microbial community composition and contributes to disease suppression. In this work, we characterized... (Comparative Study)
Comparative Study
BACKGROUND
Production of antibiotics to inhibit competitors affects soil microbial community composition and contributes to disease suppression. In this work, we characterized whether Streptomyces bacteria, prolific antibiotics producers, inhibit a soil borne human pathogenic microorganism, Streptomyces sudanensis. S. sudanensis represents the major causal agent of actinomycetoma - a largely under-studied and dreadful subcutaneous disease of humans in the tropics and subtropics. The objective of this study was to evaluate the in vitro S. sudanensis inhibitory potential of soil streptomycetes isolated from different sites in Sudan, including areas with frequent (mycetoma belt) and rare actinomycetoma cases of illness.
RESULTS
Using selective media, 173 Streptomyces isolates were recovered from 17 sites representing three ecoregions and different vegetation and ecological subdivisions in Sudan. In total, 115 strains of the 173 (66.5%) displayed antagonism against S. sudanensis with different levels of inhibition. Strains isolated from the South Saharan steppe and woodlands ecoregion (Northern Sudan) exhibited higher inhibitory potential than those strains isolated from the East Sudanian savanna ecoregion located in the south and southeastern Sudan, or the strains isolated from the Sahelian Acacia savanna ecoregion located in central and western Sudan. According to 16S rRNA gene sequence analysis, isolates were predominantly related to Streptomyces werraensis, S. enissocaesilis, S. griseostramineus and S. prasinosporus. Three clusters of isolates were related to strains that have previously been isolated from human and animal actinomycetoma cases: SD524 (Streptomyces sp. subclade 6), SD528 (Streptomyces griseostramineus) and SD552 (Streptomyces werraensis).
CONCLUSION
The in vitro inhibitory potential against S. sudanensis was proven for more than half of the soil streptomycetes isolates in this study and this potential may contribute to suppressing the abundance and virulence of S. sudanensis. The streptomycetes isolated from the mycetoma free South Saharan steppe ecoregion show the highest average inhibitory potential. Further analyses suggest that mainly soil properties and rainfall modulate the structure and function of Streptomyces species, including their antagonistic activity against S. sudanensis.
Topics: Antibiosis; DNA, Bacterial; DNA, Ribosomal; Forests; Grassland; Humans; Mycetoma; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Soil Microbiology; South Sudan; Streptomyces; Sudan
PubMed: 32050891
DOI: 10.1186/s12866-020-1717-y -
Archives of Razi Institute Oct 2021The bacterial isolates were obtained from the soil and cultivated in a wheat bran medium, which was used to produce the L-glutamate oxidase enzyme. The extracellular...
The bacterial isolates were obtained from the soil and cultivated in a wheat bran medium, which was used to produce the L-glutamate oxidase enzyme. The extracellular enzyme was then extracted using a cooling centrifugation process to obtain the filtrate that represents the crude enzyme. Afterward, the enzyme purification processes were carried out which included precipitation with ammonium sulfate as a preliminary purification step followed by dialysis to remove the salts. Next, ion-exchange chromatography and gel filtration were used to finish the purification process, and the enzyme activity was determined for each purification step. The results of purification of L-glutamate oxidase enzyme from using ammonium sulfate showed that the specific activity was 8.25 units/mg protein with a saturation ratio of 60%. Moreover, the results of purification using a dialysis tube indicated that the specific activity was 9.5 units/mg protein. In addition, the result of purification using diethylaminoethyl cellulose ion column revealed that the specific activity was 25 unit/mg protein and the results of purification using gel filtration showed that the specific activity was 56 units/mg protein which was the best step in the purification process due to high specific activity of the enzyme. The optimum temperature and pH for the activity and stability of the enzyme were tested. Based on the findings, the optimum temperature for the activity of the enzyme was 37 °C. In addition, it was found that the optimum temperature range for the stability of the enzyme was 30-50 °C. Besides, the optimum pH for the activity was 7.0 and the optimum pH range for the enzyme stability was 5.0-7.0.
Topics: Amino Acid Oxidoreductases; Animals; Bacterial Proteins; Enzyme Stability; Hydrogen-Ion Concentration; Streptomyces
PubMed: 35096313
DOI: 10.22092/ari.2021.355928.1738 -
Microbial Genomics Jan 2022The development of spots or lesions symptomatic of common scab on root and tuber crops is caused by few pathogenic with 87-22 as the model species. Thaxtomin... (Comparative Study)
Comparative Study
The development of spots or lesions symptomatic of common scab on root and tuber crops is caused by few pathogenic with 87-22 as the model species. Thaxtomin phytotoxins are the primary virulence determinants, mainly acting by impairing cellulose synthesis, and their production in is in turn boosted by cello-oligosaccharides released from host plants. In this work we aimed to determine which molecules and which biosynthetic gene clusters (BGCs) of the specialized metabolism of 87-22 show a production and/or a transcriptional response to cello-oligosaccharides. Comparative metabolomic analyses revealed that molecules of the virulome of induced by cellobiose and cellotriose include (i) thaxtomin and concanamycin phytotoxins, (ii) desferrioxamines, scabichelin and turgichelin siderophores in order to acquire iron essential for housekeeping functions, (iii) ectoine for protection against osmotic shock once inside the host, and (iv) bottromycin and concanamycin antimicrobials possibly to prevent other microorganisms from colonizing the same niche. Importantly, both cello-oligosaccharides reduced the production of the spore germination inhibitors germicidins thereby giving the 'green light' to escape dormancy and trigger the onset of the pathogenic lifestyle. For most metabolites - either with induced or reduced production - cellotriose was revealed to be a slightly stronger elicitor compared to cellobiose, supporting an earlier hypothesis which suggested the trisaccharide was the real trigger for virulence released from the plant cell wall through the action of thaxtomins. Interestingly, except for thaxtomins, none of these BGCs' expression seems to be under direct control of the cellulose utilization repressor CebR suggesting the existence of a yet unknown mechanism for switching on the virulome. Finally, a transcriptomic analysis revealed nine additional cryptic BGCs that have their expression awakened by cello-oligosaccharides, suggesting that other and yet to be discovered metabolites could be part of the virulome of .
Topics: Biosynthetic Pathways; Cellobiose; Cellulose; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Macrolides; Metabolomics; Multigene Family; Piperazines; Plant Tubers; RNA-Seq; Streptomyces; Trioses; Virulence Factors
PubMed: 35040428
DOI: 10.1099/mgen.0.000760 -
BMC Genomics Dec 2019Bacteria within the genus Streptomyces remain a major source of new natural product discovery and as soil inoculants in agriculture where they promote plant growth and...
BACKGROUND
Bacteria within the genus Streptomyces remain a major source of new natural product discovery and as soil inoculants in agriculture where they promote plant growth and protect from disease. Recently, Streptomyces spp. have been implicated as important members of naturally disease-suppressive soils. To shine more light on the ecology and evolution of disease-suppressive microbial communities, we have sequenced the genome of three Streptomyces strains isolated from disease-suppressive soils and compared them to previously sequenced isolates. Strains selected for sequencing had previously showed strong phenotypes in competition or signaling assays.
RESULTS
Here we present the de novo sequencing of three strains of the genus Streptomyces isolated from disease-suppressive soils to produce high-quality complete genomes. Streptomyces sp. GS93-23, Streptomyces sp. 3211-3, and Streptomyces sp. S3-4 were found to have linear chromosomes of 8.24 Mb, 8.23 Mb, and greater than 7.5 Mb, respectively. In addition, two of the strains were found to have large, linear plasmids. Each strain harbors between 26 and 38 natural product biosynthetic gene clusters, on par with previously sequenced Streptomyces spp. We compared these newly sequenced genomes with those of previously sequenced organisms. We see substantial natural product biosynthetic diversity between closely related strains, with the gain/loss of episomal DNA elements being a primary driver of genome evolution.
CONCLUSIONS
Long read sequencing data facilitates large contig assembly for high-GC Streptomyces genomes. While the sample number is too small for a definitive conclusion, we do not see evidence that disease suppressive soil isolates are particularly privileged in terms of numbers of biosynthetic gene clusters. The strong sequence similarity between GS93-23 and previously isolated Streptomyces lydicus suggests that species recruitment may contribute to the evolution of disease-suppressive microbial communities.
Topics: Biological Products; Biosynthetic Pathways; Genome, Bacterial; Phenotype; Sequence Analysis, DNA; Soil Microbiology; Streptomyces
PubMed: 31856709
DOI: 10.1186/s12864-019-6279-8 -
Microbiological Research Jan 2017Biological Nitrogen Fixation is critical for ecosystem productivity. Select members of Bacteria and Archaea express a nitrogenase enzyme complex that reduces atmospheric...
Biological Nitrogen Fixation is critical for ecosystem productivity. Select members of Bacteria and Archaea express a nitrogenase enzyme complex that reduces atmospheric nitrogen to ammonia. Several nitrogen fixing bacteria form symbiotic associations with plants, but free-living diazotrophs also contribute a substantial amount of nitrogen to ecosystems. The aim of this study was to isolate and characterize free-living diazotrophs in arid lands of South Dakota Badlands. Samples were obtained from sod tables and the surrounding base in spring and fall. Diazotrophs were isolated on solid nitrogen free medium (NFM) under hypoxic conditions, and their16S rRNA and nifH genes sequenced. nifH was also amplified directly from soil DNA extracts. The 16S rRNA gene data indicated a diversity of putative free-living diazotrophs across 4 phyla (Actinomycetes, Proteobacteria, Bacteroidetes, and Firmicutes), but ∼50% of these clustered with Streptomyces. These Streptomyces isolates grew in liquid NFM in an ammonia-depleted environment. Only 5 of these yielded a nifH gene product using the PolF/PolR primer set. Four of these aligned with nifH of the cyanobacteria Scytonema and Nostoc, and the other one aligned with nifH of Bradyrhizobium. Six selected Streptomyces isolates, three of which were nifH positive by PCR, all indicated N incorporation, providing strong support of nitrogen fixation. All nifH amplicons from soil DNA extract resembled Cyanobacteria. This is the first known report of diazotrophic Streptomyces, other than the thermophilic, autotrophic S. thermoautotrophicus. nifH genes of these Streptomyces were related to those from Cyanobacteria. It is possible that the cyanobacteria-like nifH amplicons obtained from soil DNA were associated with Streptomyces.
Topics: Biodiversity; Cluster Analysis; Culture Media; DNA, Bacterial; DNA, Ribosomal; Nitrogen Fixation; Oxidoreductases; Phylogeny; Polymerase Chain Reaction; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Soil Microbiology; South Dakota; Streptomyces
PubMed: 28024524
DOI: 10.1016/j.micres.2016.11.004