Streptomycete Strains Research Articles

Comparative Genomics Analysis of Streptomyces Species Reveals Their Adaptation to the Marine Environment and Their Diversity at the Genomic Level.

Over 200 genomes of streptomycete strains that were isolated from various environments are available from the NCBI. However, little is known about the characteristics that are linked to marine adaptation in marine-derived streptomycetes. The particularity and complexity of the marine environment suggest that marine streptomycetes are genetically diverse. Here, we sequenced nine strains from the Streptomyces genus that were isolated from different longitudes, latitudes, and depths of the South China Sea. Then we compared these strains to 22 NCBI downloaded streptomycete strains. Thirty-one streptomycete strains are clearly grouped into a marine-derived subgroup and multiple source subgroup-based phylogenetic tree. The phylogenetic analyses have revealed the dynamic process underlying streptomycete genome evolution, and lateral gene transfer is an important driving force during the process. Pan-genomics analyses have revealed that streptomycetes have an open pan-genome, which reflects the diversity of these streptomycetes and guarantees the species a quick and economical response to diverse environments. Functional and comparative genomics analyses indicate that the marine-derived streptomycetes subgroup possesses some common characteristics of marine adaptation. Our findings have expanded our knowledge of how ocean isolates of streptomycete strains adapt to marine environments. The availability of streptomycete genomes from the South China Sea will be beneficial for further analysis on marine streptomycetes and will enrich the South China Sea’s genetic data sources.

Algicidal Activity of Streptomyces eurocidicus JXJ-0089 Metabolites and Their Effects on Microcystis Physiology.

Copper sulfate (CuSO4) has been widely used as an algicide to control harmful cyanobacterial blooms (CyanoHABs) in freshwater lakes. However, there are increasing concerns about this application, due mainly to the general toxicity of CuSO4 to other aquatic species and its long-term persistence in the environment. This study reported the isolation and characterization of two natural algicidal compounds, i.e., tryptamine and tryptoline, from Streptomyces eurocidicus JXJ-0089. At a concentration of 5 μg/ml, both compounds showed higher algicidal efficiencies than CuSO4 on Microcystis sp. FACHB-905 and some other harmful cyanobacterial strains. Tryptamine and tryptoline treatments induced a degradation of chlorophyll and cell walls of cyanobacteria. These two compounds also significantly increased the intracellular oxidant content, i.e., superoxide anion radical (O2 (-)) and malondialdehyde (MDA), but reduced the activity of intracellular reductants, i.e., superoxide dismutase (SOD), of cyanobacteria. Moreover, tryptamine and tryptoline treatments significantly altered the internal and external contents of microcystin-LR (MC-LR), a common cyanotoxin. Like CuSO4, tryptamine and tryptoline led to releases of intracellular MC-LR from Microcystis, but with lower rates than CuSO4 Tryptamine and tryptoline (5 μg/ml) in cyanobacterial cultures were completely degraded within 8 days, while CuSO4 persisted for months. Overall, our results suggest that tryptamine and tryptoline could potentially serve as more efficient and environmentally friendly alternative algicides than CuSO4 in controlling harmful cyanobacterial blooms. Cyanobacterial harmful algal blooms (CyanoHABs) in aquatic environments have become a worldwide problem. Numerous efforts have been made to seek means to prevent, control, and mitigate CyanoHABs. Copper sulfate (CuSO4), was once a common algicide to treat and control CyanoHABs. However, its application has become limited due to concerns about its general toxicity to other aquatic species and its long-term persistence in the environment. There is a great need for algicides with higher specificity and low environmental impacts. This study reports the isolation and characterization of two natural algicidal compounds from a streptomycete strain, Streptomyces eurocidicus JXJ-0089. Our results suggest that the identified algicides could potentially serve as more efficient and environmentally friendly alternative algicides than CuSO4 in controlling harmful cyanobacterial blooms.

Characterization of Antimycins – Producing Streptomycete Strain VY46 Isolated from Slovak Soil

The strain no. VY46 was isolated from agricultural soil of Slovak republic and tested for potential antimicrobial activity against various human pathogens. On the basis of results, strain VY46 significantly inhibited growth of yeast Candida albicans and therefore was used for further characterization. In order to explore the potential bioactivities, extract of the fermented broth culture was prepared with organic solvent extraction method. The ethylacetate extract was subjected to HPLC fractionation against Candida albicans and followed by LC/MS analysis for potential production of anticandidal substances. The analysis resulted in the identification of two antimycins antibiotics, which may be responsible for important anticandidal activity of the strain. On the basis of liquid chromatography and mass spectrometry the antibiotics were identified as Urauchimycin A and Kitamycin A. According tothe results from cultural, morphological, physiological, biochemical and 16S rRNA gene sequence methods, the strain was identified as Streptomyces albidoflavus. In addition, neighbor-joining phylogenetic tree confirmed the relationships of this strain to other members of Streptomyces genera.

NFAT-133 increases glucose uptake in L6 myotubes by activating AMPK pathway

NFAT-133 is an aromatic compound with cinammyl alcohol moiety, isolated from streptomycetes strain PM0324667. We have earlier reported that NFAT-133 increases insulin stimulated glucose uptake in L6 myotubes using a PPARγ independent mechanism and reduces plasma or blood glucose levels in diabetic mice. Here we investigated the effects of NFAT-133 on cellular signaling pathways leading to glucose uptake in L6 myotubes. Our studies demonstrate that NFAT-133 increases glucose uptake in a dose- and time-dependent manner independent of the effects of insulin. Treatment with Akti-1/2, wortmannin and increasing concentrations of insulin had no effect on NFAT-133 mediated glucose uptake. NFAT-133 induced glucose uptake is completely mitigated by Compound C, an AMPK inhibitor. Further, the kinases upstream of AMPK activation namely; LKB-1 and CAMKKβ are not involved in NFAT-133 mediated AMPK activation nor does the compound NFAT-133 have any effect on AMPK enzyme activity. Further analysis confirmed that NFAT-133 indirectly activates AMPK by reducing the mitochondrial membrane potential and increasing the ratio of AMP:ATP.

Streptomyces alfalfae sp. nov. and comparisons with its closest taxa Streptomyces silaceus, Streptomyces flavofungini and Streptomyces intermedius.

A novel streptomycete strain, designated XY25T, was isolated from the rhizosphere soil in an alfalfa field in Jingyang, Shanxi, China. The isolate showed optimal growth at 37 °C, and was capable of growing at pH 6-10 and in the presence of 0-6 % (w/v) NaCl. Mycelia of strain XY25T appeared spiral and developed into white spore chains with long-rod spores and a smooth surface. The 16S rRNA gene sequence of XY25T was determined and was found to be highly similar to those of species of the genus Streptomyces including Streptomyces silaceus DSM 41861T (99.11 % 16S rRNA gene sequence similarity), Streptomyces flavofungini DSM 40366T (98.49 %) and Streptomyces intermedius DSM 40372T (98.43 %), all of which were used for further characterization. Each of the four streptomycetes showed distinctive patterns of carbon usage and fatty acids composition. Analysis of cellular components of strain XY25T revealed ll-diaminopimelic acid as diagnostic diamino acid and xylose as the major sugar, whereas polar lipids were determined as phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol, an unknown phospholipid, two unknown phosphatidylinositol mannosides and several unknown lipids. Menaquinones were dominated by MK-9(H6) and MK-9(H8), and the main fatty acids were anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0. DNA-DNA hybridization studies indicated that strain XY25T showed relatedness values of 35.2-40.42 % with the closest related species. Based on these results, strain XY25T represents a novel species of the genus Streptomyces, for which the name Streptomyces alfalfae sp. nov. is proposed. The type strain is XY25T ( = KCTC 39571T = CCTCC AA2015019T).

Role of genes snoaM, snoaL, and snoaE in the biosynthesis of nogalamycin in Streptomyces nogalater Lv65

Bioinformatic analysis of snoaL, snoaM, and snoaE genes from Streptomyces nogalater, a microorganism producing the anthracycline antibiotic nogalamycin, is reported. The results of phylogenetic analysis demonstrated high similarity of SnoaL, SnoaM, and SnoaE proteins to cyclases involved in the biosynthesis of various antibiotics. Insertional inactivation of polyketide cyclase genes in the chromosome of S. nogalater Lv65 was performed, and S. nogalater strains MI, LI, and EI were thus obtained. Inactivation of the above named genes did not affect the morphologic characteristics of S. nogalater. The inability of strains MI, LI, and EI to synthesize nogalamycin was demonstrated. Antibiotic synthesis was restored when extra copies of snoaL, snoaM, and snoaE genes were introduced into the above named strains. Streptomycete strains obtained in the present work, as well as nogalamycin cyclase genes, can be used in combinatorial biosynthesis of anthracyclin antibiotics.

Accumulation of a bioactive benzoisochromanequinone compound kalafungin by a wild type antitumor-medermycin-producing streptomycete strain.

Medermycin and kalafungin, two antibacterial and antitumor antibiotics isolated from different streptomycetes, share an identical polyketide skeleton core. The present study reported the discovery of kalafungin in a medermycin-producing streptomycete strain for the first time. A mutant strain obtained through UV mutagenesis showed a 3-fold increase in the production of this antibiotic, compared to the wild type strain. Heterologous expression experiments suggested that its production was severely controlled by the gene cluster for medermycin biosynthesis. In all, these findings suggested that kalafungin and medermycin could be accumulated by the same streptomycete and share their biosynthetic pathway to some extent in this strain.

Antimicrobial Activity and Identification of Actinomycete Strains from a Folk Medicinal Soil in China

Objective: To discover novel antimicrobial medicinal resource and reveal the anti-infection reasons of a folk medicinal soil. Methods: The antimicrobial activities of sixty-one actinomycete strains isolated from a folk medicinal soil sample were evaluated using agar well diffusion and broth microdilution methods, and then seven strains with broadspectrum antimicrobial activities were identified using polyphasic taxonomy procedure. Results: Thirteen strains presented antimicrobial activities, and seven strains showed broad-spectrum antimicrobial activities with the minimum inhibitory concentrations (MICs) of 0.256-4.096 mg/ml against four pathogenic microorganisms including methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus (MRSA) and Candida albicans. Moreover, strain ZZ035 also showed antimicrobial activities with the MICs of 0.256-1.024 mg/ml against Escherichia coli. The identifications of these seven strains showed that all of them belonged to the genus Streptomyces. Furthermore, strain ZZ016 presented a high potential to be a new species. Conclusion: These streptomycete strains were deduced to be mainly responsible for the anti-infection effect of the folk medicinal soil, and further research on their secondary metabolites may lead to the discovery of remarkable and broad-spectrum antibiotics, especially that of anti-MRSA ones.

Antibacterial potential of streptomycete strains from Antarctic soils

The exploration of habitats with unusual environment and poorly explored areas such as Antarctica is one of the strategies for discovery of new biologically active substances and/or new producers. The aim of this study was to identify the actinomycetes isolated from the soils of the island Livingston – Antarctica and to investigate their potential to synthesize antibacterial agents against phytopathogens. Twenty-three actinomycete strains were the object of this study. Using PCR (polymerase chain reaction) amplification all strains were affiliated to genus Streptomyces.The sequencing of the 16S rRNA for three of the strains showed greatest similarity to Streptomyces tendae for one of them, and revealed that the other strains had closest relations to streptomycetes isolated from anthropogenically unaltered regions including Antarctica.The isolates were studied for production of antibacterial substances both by molecular and culture methods. PCR targeting specific biosynthetic genes involved in the production of some groups of antibiotics was performed. The screening showed that all strains possessed the gene for Type-II polyketide synthase, 11 strains – for non-ribosomal peptide synthetase; 6 strains – for polyene antibiotics; and 4 strains – for glycopeptide antibiotics. The production of antibacterial substances by the strains was tested in vitro against phytopathogenic bacteria. The strains differed in the number of inhibited test – bacteria and in their spectrum of action. Four strains showed a wide range of activity against Gram-positive and Gram-negative phytopathogens.The results obtained revealed that the Antarctic soils are potential source for isolation of streptomycetes producing antibiotics from different groups.

Biosynthesis of colabomycin E, a new manumycin-family metabolite, involves an unusual chain-length factor.

Colabomycin E is a new member of the manumycin-type metabolites produced by the strain Streptomyces aureus SOK1/5-04 and identified by genetic screening from a library of streptomycete strains. The structures of colabomycin E and accompanying congeners were resolved. The entire biosynthetic gene cluster was cloned and expressed in Streptomyces lividans. Bioinformatic analysis and mutagenic studies identified components of the biosynthetic pathway that are involved in the formation of both polyketide chains. Recombinant polyketide synthases (PKSs) assembled from the components of colabomycin E and asukamycin biosynthetic routes catalyzing the biosynthesis of "lower" carbon chains were constructed and expressed in S. aureus SOK1/5-04 ΔcolC11-14 deletion mutant. Analysis of the metabolites produced by recombinant strains provided evidence that in both biosynthetic pathways the length of the lower carbon chain is controlled by an unusual chain-length factor supporting biosynthesis either of a triketide in asukamycin or of a tetraketide in colabomycin E. Biological activity assays indicated that colabomycin E significantly inhibited IL-1β release from THP-1 cells and might thus potentially act as an anti-inflammatory agent.

Regio- and stereoselective intermolecular oxidative phenol coupling in Streptomyces.

Intermolecular oxidative phenol coupling is the main process in nature for the formation of atroposelective biaryl compounds. Although well defined in plants and fungi, this type of dimerization reaction in bacteria is poorly understood. Therefore, the biosynthesis of julichromes, spectomycins, and setomimycin was investigated. The monomeric subunits of these biarylic pre-anthraquinones are derived from a common polyketidic precursor, yet the coupling reaction proceeds in a regioselective manner, with the position of attachment of the two subunits depending on the specific streptomycete strain. By using genome analysis and deletion experiments, the biosynthetic gene clusters were identified. Furthermore, it was established that cytochrome P450 enzymes are fundamentally involved during dimerization of the polyketide monomers.

Activation and identification of five clusters for secondary metabolites in Streptomyces albus J1074.

Streptomyces albus J1074 is a streptomycete strain widely used as a host for expression of secondary metabolite gene clusters. Bioinformatic analysis of the genome of this organism predicts the presence of 27 gene clusters for secondary metabolites. We have used three different strategies for the activation of some of these silent/cryptic gene clusters in S. albus J1074: two hybrid polyketide-non-ribosomal peptides (PK-NRP) (antimycin and 6-epi-alteramides), a type I PK (candicidin), a non-ribosomal peptides (NRP) (indigoidine) and glycosylated compounds (paulomycins). By insertion of a strong and constitutive promoter in front of selected genes of two clusters, production of the blue pigment indigoidine and of two novel members of the polycyclic tetramate macrolactam family (6-epi-alteramides A and B) was activated. Overexpression of positive regulatory genes from the same organism also activated the biosynthesis of 6-epi-alteramides and heterologous expression of the regulatory gene pimM of the pimaricin cluster activated the simultaneous production of candicidins and antimycins, suggesting some kind of cross-regulation between both clusters. A cluster for glycosylated compounds (paulomycins) was also identified by comparison of the high-performance liquid chromatography profiles of the wild-type strain with that of a mutant in which two key enzymes of the cluster were simultaneously deleted.

MALDI‐TOF mass spectrometry, an efficient technique for in situ detection and characterization of actinomycins

An extensive study of actinomycins was performed using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). Actinomycins represent a well-known family of peptidolactone chromopeptides with potent cytostatic and antibiotic properties. Using five well-characterized streptomycete strains, we introduced MALDI-TOF MS as an efficient technique for rapid in situ detection of actinomycins in surface extracts of cells picked from agar plates. By this procedure, actinomycin complexes can be investigated with high sensitivity and accuracy in a minimum of time. These studies were complemented by mass spectrometric investigation of actinomycins obtained from culture filtrate extracts and purified by high-performance liquid chromatography to detect yet unknown actinomycin species. By feeding experiments, C-demethyl-actinomycins from Streptomyces chrysomallus and Streptomyces parvulus as well as hemi-actinomycins from Streptomyces antibioticus lacking one of the two pentapeptide lactone rings were isolated and characterized as novel variants for structure-activity relationship studies. Structural characterization of the investigated actinomycins was performed by post source decay MALDI-TOF MS. The specific features of the fragmentation patterns of the protonated and cationized forms of selected actinomycins were investigated in detail.

Isolation and characterization of soil Streptomyces species as potential biological control agents against fungal plant pathogens

The use of antagonist microorganisms against fungal plant pathogens is an attractive and ecologically alternative to the use of chemical pesticides. Streptomyces are beneficial soil bacteria and potential candidates for biocontrol agents. This study reports the isolation, characterization and antagonist activity of soil streptomycetes from the Los Petenes Biosphere Reserve, a Natural protected area in Campeche, Mexico. The results showed morphological, physiological and biochemical characterization of six actinomycetes and their inhibitory activity against Curvularia sp., Aspergillus niger, Helminthosporium sp. and Fusarium sp. One isolate, identified as Streptomyces sp. CACIS-1.16CA showed the potential to inhibit additional pathogens as Alternaria sp., Phytophthora capsici, Colletotrichum sp. and Rhizoctonia sp. with percentages ranging from 47 to 90%. This study identified a streptomycete strain with a broad antagonist activity that could be used for biocontrol of plant pathogenic fungi.

Screening of antifungi endophytic actinomyces strains from Salvia przewalskii in Tibean Plateau

Twenty-four endophytic actinomycetes strains were isolated from the Salvia przewalskii in Tibetan Plateau of China by tablet coating method. Fusarium moniliforme, Helminthosporium turcicum and Bipolaris maydis were selected as indicator fungi to test the antimicrobial activities of these endophytic actinomycetes by tablet confrontation method. The results showed that 21 strains can produce antimicrobial substances which accounts for 85.7% of the total separates number. Four strains of endogenous actinomyces have more obvious antifungi activity. According to results of morphology and culture properties and 16S rDNA sequences of endophytic actinomyces, it is concluded that all of the isolates were streptomycetes trains.

Streptomyces chilikensis sp. nov., a halophilic streptomycete isolated from brackish water sediment

A novel actinobacterial strain, designated RC 1830(T), was isolated from the sediment of estuarine coastal brackish water lagoon of Chilika Lake, in Khurdha district of Odisha, India, and characterized using a polyphasic approach. Strain RC 1830(T) was halophilic and alkali-tolerant and found to hydrolyse chitin, starch, tributyrin, lecithin, Tween 80, cellulose, gelatin and casein. The diagnostic presence of ll-diaminopimelic acid, iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0, C16 : 0, iso-C17 : 0, anteiso-C17 : 0 as major cellular fatty acids and MK-9(H4 and H6) as major menaquinones noticeably associated the strain to the genus Streptomyces. After comparison and analysis of the near complete 16S rRNA gene sequence with representative strains of other streptomycetes, it was evident that strain RC 1830(T) belonged to the genus Streptomyces, and exhibited the highest sequence similarities of 99.53 %, 99.25 %, 99.11 %, 99.10 % and 99. 06 % to Streptomyces fragilis DSM 40044(T), Streptomyces coelicoflavus NBRC 15399(T), Streptomyces flaveolus NBRC 3715(T), Streptomyces lavenduligrisesus NBRC 13405(T) and Streptomyces eurythermus ATCC 14975(T), respectively. Reconstruction of a phylogenetic tree for the genus Streptomyces revealed that strain RC 1830(T) formed a distinct phyletic line and clustered with its most closely related neighbour S. fragilis DSM 40044(T). The DNA-DNA relatedness values between strain RC 1830(T) and the most closely related type strain S. fragilis DSM 40044(T) were determined to be 17.7 ± 4.55 %. Additionally, morphological, biochemical and physiological tests were able to distinguish the strain from the most closely related type strain S. fragilis DSM 40044(T) and other closely related neighbours, S. coelicoflavus DSM 41471(T) and Streptomyces flaveolus DSM 40061(T). Based on a range of phenotypic and genotypic properties, strain RC 1830(T) is suggested to represent a novel species of the genus Streptomyces for which the name Streptomyces chilikensis sp. nov. is proposed. The type strain is RC 1830(T) ( = JCM 18411(T) = DSM 42072(T)).

Non-streptomycete actinomycetes nourish the current microbial antibiotic drug discovery.

OPINION article Front. Microbiol., 20 August 2013Sec. Antimicrobials, Resistance and Chemotherapy Volume 4 - 2013 | https://doi.org/10.3389/fmicb.2013.00240

Diversity and Bioactivity of Cultivable Animal Fecal Actinobacteria

Microbial symbionts play important roles in food digestion and absorption, immunity, pathogens resistance, and health maintaining of their hosts by coevolution. To provide new sources for discovering new leader compounds of drugs, the diversity and bioactivities of cultivable actinobacteria from animal feces have been studied. 31 species of animal fecal samples were collected fromYunnanWildAnimalPark. The purified cultures of actinobacteria were isolated from these samples by using 5 media. The 16S rRNA gene sequences of 528 selected strains were determined, the phylogenetic analysis was carried out, and anti-microbial and anti-tumor activities were determined. 35 genera (including a new genus, Enteractinococcus) of actinobacteria from the 31 species of animal feces were identified. Some strains had high anti-tumor and antimicrobial activities. More than 50 secondary metabolites were isolated and identified, a novel bioactive macrolactam polyketide glycoside, Sannastatin, was found. Nine fecal streptomycete strains were fermented respectively, blended to the microbial manure, and used to prophylaxis and treatment of soil-borne disease of notoginseng in field. The incidence rate of the disease was lower 81% than agricultural chemicals. Fecal actinobacteria, a possibility as a new source for discovering drug leader, agricultural chemicals and other industry products, will be discussed.

Effect of Streptomyces Metabolites on Some Physiological Parameters of Maize Seeds

The influence of metabolites of actinomycetes on some physiological parameters of maize seeds of hybrid of Debut variety (roots formation, growth of coleoptiles) has been studied. The strains of actinomycetes genus Streptomyces were isolated from various soil samples of R.Moldova with different content of humus. The obtained data showed that the number of roots increased considerably under the influence of metabolites of Streptomyces sp .47, Streptomyces sp .123, Streptomyces sp .154 and Streptomyces sp .182 (19,4%, 16,6% and 13,8% respectively, compared with the control - water). The increasing by 33,0 and 44,8% of the main root in comparison with the control was determined after the treatment with metabolites of Streptomyces sp .11 and Streptomyces sp .123 strains. The metabolites of Streptomyces sp .154 and Streptomyces sp .182 strains led to an increasing of coleoptiles length on 31,3 and 38,1% respectively. The dry weight of the roots and coleoptiles exceeded the control on 30-80% and 25-75% respectively in experimental variants. Our research showed that the investigated streptomycetes strains are capable to synthesize the substances which stimulate roots forming and development of stems. In summary, the isolated from Moldavian soils strains of streptomycetes can be considered as potential producers of plant growth regulators.

English

The streptomycete strain SCY114 was isolated from a soil sample of Xuchang in Henan province, China. It possessed smooth grey spores borne in rectiflexible and spiral chains and was capable of using all of the International Streptomyces Project sugars. The melting temperature and G+C content were 81.8℃ and 61.6 mol%, respectively. The level of 16S rRNA gene sequence similarity be- tween strain SCY114 and S. scabies ATCC49173 was 99.8%. However, the values of DNA-DNA relatedness between strain SCY114 and S. scabies ATCC49173 was 65.2%, and the strain SCY114 did not exhibit pathogenicity towards potato plants. Based on the pheno- typic and genotypic evidence, strain SCY114 was identified as a subspecies of the Streptomyces scabiei, for which the name Streptomy- ces scabiei subsp. xuchangensis is proposed. Strain SCY114 strongly inhibited the in vitro mycelial growth of Gaeumannomyces graminis var. tritici as well as various other plant pathogenic fungi. The filtered culture broth of strain SCY114 was substantially more effective at controlling wheat take-all compared to the silthiofam, and the disease was reduced by 78.2%. An antifungal antibiotic was isolated from the fermentation broth of strain SCY114 using a series of chromatographic procedures. The molecular formula of the antibiotic was deter- mined to be C28H26N4O3, and on the basis of the NMR data, the antibiotic was confirmed to be staurosporine.