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At least 19 recordsLinked to original sources
PubMed2026

Streptomyces violaceusniger WZS5-6 suppresses Fusarium oxysporum f. sp. cubense tropical race 4 via antifungal metabolites and host defense induction.

INTRODUCTION: Fusarium wilt of banana (FWB), caused by Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4), poses a serious threat to the safety and sustainable development of the banana industry. Biological control represents one of the most environmentally friendly approaches for managing this disease. METHODS: In this study, Streptomyces violaceusniger WZS5-6 antifungal activity against Foc TR4 has been investigated through an integrated approach combining antifungal assays, genome analysis, and metabolomic profiling. For the purpose, the effects of the bacterial strain and its cell-free extract on morphological and ultrastructural changes on pathogenic fungal hyphae and spores were assessed using scanning and transmission electron microscopy. LC-MS analysis was used to identify the metabolites responsible for antifungal activity. We further explored the potential of S. violaceusniger WZS5-6 against Foc TR4 through in planta validation. RESULTS: Streptomyces violaceusniger WZS5-6 exhibited a strong inhibition rate of 91.57% on Foc TR4. The cell-free extract obtained from S. violaceusniger WZS5-6 strongly inhibited Foc TR4 with an EC50 value of 91.62 µg·mL-1, indicating the presence of antifungal bioactive metabolites. The results showed that S. violaceusniger WZS5-6 significantly inhibited the mycelial growth of Foc TR4 and induced alterations in spore morphology, mycelial ultrastructure, and cell membrane leakage. Metabolomic profiling of the S. violaceusniger WZS5-6 extracts revealed numerous antifungal metabolites, among which the key metabolites, viz., citronellic acid and furanodienone, exhibited strong inhibitory effects on Foc TR4, with antifungal activity of 61.13% and 57.44%, respectively. Moreover, strain WZS5-6 not only demonstrated 61.54% control efficacy against FWB in a pot experiment but also showed promising growth-promoting effects on banana plants. DISCUSSION: This study demonstrates that S. violaceusniger WZS5-6 inhibits Foc TR4 through a multi-level mechanism involving cellular disruption, metabolic adaptation, and activation of host defense responses. These findings highlight the potential of S. violaceusniger WZS5-6 as a promising novel candidate strain to be employed as a biological control agent of FWB.

Fusarium wilt of banana↗
PubMed2000

Selective isolation and characterisation of members of the Streptomyces violaceusniger clade associated with the roots of Paraserianthes falcataria.

Large numbers of putatively novel streptomycetes were isolated from environmental samples collected from in and around the root system of the tropical angiosperm, Paraserianthes falcataria. Representative isolates were assigned to 37 multi-membered and 107 single membered colour groups based on their ability to form pigments on oatmeal and peptone yeast extract iron agars. The largest taxon, colour group 3, encompassed 94 isolates which had morphological properties typical of members of the Streptomyces violaceusniger clade. Twelve representatives of this taxon chosen on the basis of Curie-point pyrolysis mass spectrometric data were compared with representatives of the validly described species which constitute the Streptomyces violaceusniger clade. Six out of the twelve representative strains were readily distinguished from one another and from the marker strains using a combination of genotypic and phenotypic properties. These organisms were consequently considered to merit species status as Streptomyces asiaticus sp. nov., Streptomyces cangkringensis sp. nov., Streptomyces indonesiensis sp. nov., Streptomycesjavensis sp. nov., Streptomyces rhizosphaerius sp. nov. and Streptomyces yogyakartensis sp. nov.

Bacteriological Techniques↗
PubMed2004

Selective isolation of bioactive soil actinomycetes belonging to the Streptomyces violaceusniger phenotypic cluster.

AIMS: To devise and evaluate a strategy for isolating members of the Streptomyces violaceusniger phenotypic cluster, which are known to be a promising source of bioactive metabolites. METHODS AND RESULTS: The treatment of four soil samples with 1.5% phenol (30 degrees C, 30 min) prior to inoculation on humic acid-vitamin (HV) agar eliminated most of the streptomycetes and other bacterial populations. The surviving streptomycetes on the HV isolation plates were subcultured, and species-group identification was made according to the probabilistic identification system of Williams et al. (1989). Of the 133 streptomycetes subcultured, 102 (77%), were assigned to the S. violaceusniger cluster. A test with an overlay technique revealed that all of these S. violaceusniger-cluster isolates had broad antimicrobial spectra, as they inhibited the growth of all test Gram-positive bacteria, yeasts and filamentous fungi. Antitumour activity against colon carcinoma cells was found among 68 or 67%, of these S. violaceusniger-cluster isolates, following growth in submerged culture. CONCLUSIONS: Chemical pretreatment of soil samples with phenol reduces the growth of ubiquitous Streptomyces species, thereby facilitating the recovery of less-abundant S. violaceusniger-cluster strains that are characterized by high antimicrobial and antitumour activities. SIGNIFICANCE AND IMPACT OF THE STUDY: The development and application of new methodologies with which to selectively isolate rare, bioactive streptomycete groups is important for discovering novel secondary metabolites with bioactive properties.

Anti-Infective Agents↗
PubMed1998

Spirofungin, a new antifungal antibiotic from Streptomyces violaceusniger Tü 4113.

A new secondary metabolite was detected in the culture filtrate and extracts of Streptomyces violaceusniger Tü 4113 by HPLC-diode-array and HPLC-electrospray-mass-spectrometry screening. The compound named spirofungin has a polyketide-spiroketal structure and shows various antifungal activities, particularly against yeasts.

Antifungal Agents↗
PubMed1998

WA8242A1, A2 and B, novel secretory phospholipase A2 inhibitors produced by Streptomyces violaceusniger. II. Biological properties.

WA8242A1, A2 and B, novel inhibitors of secretory phospholipase A2 (PLA2), were obtained from Streptomyces violaceusniger No. 8242. WA8242B inhibited secretory group I and II PLA2s in a dose-dependent manner. The mode of inhibition of group II PLA2 by WA8242B was in competitive fashion. WA8242B inhibited group II PLA2-induced Prostaglandin I2 (PGI2) production by human umbilical vein endothelial cells. Furthermore, WA8242B was effective in mouse zymosan writhing model.

2-Aminoadipic Acid↗
PubMed1995

RS-22A, B and C: new macrolide antibiotics from Streptomyces violaceusniger. I. Taxonomy, fermentation, isolation and biological activities.

Three novel 36-membered macrolide antibiotics, RS-22A, B and C produced by Streptomyces violaceusniger have been isolated. These antibiotics were purified from an acetone extract of the mycelia followed by butanol extraction, centrifugal partition chromatography and HPLC. RS-22A, B, C showed antimicrobial activity against fungi and Gram-positive bacteria.

Anti-Bacterial Agents↗
PubMed2005

Production of 2-methylisoborneol by Streptomyces violaceusniger and its transformation by selected species of Pseudomonas.

The effect of glucose, glycerol and yeast-extract (YE) on 2-methylisoborneol (MIB) production by Streptomyces violaceusniger (C4-S strain) was determined. Glycerol as a sole carbon source promoted MIB production was maximum concentration (40.65 microg/l) after 10 days incubation, while glucose favored biomass production. Increasing YE concentration from 0.1 to 1% (W/V) repressed MIB production with 62 and 83% reduction after 10 and 14 days, respectively. Transformation of this odorous compound was investigated using seven different Pseudomonas species. Action of the different Pseudomonas spp. on the C4-S extract was followed at 1 hour, 2 hours, 6 hours and 12 hours. Pseudomonas spp. 1, 2, 3 and 5 indicated a positive reaction; however, Pseudomonas spp. 4, 6 and 7 showed no effect. These data suggest that 2-methylisoborneol can be transformed by Pseudomonas spp. and the test adopted by this study can be applied for screening organisms for their ability to transform MIB.

Biomass↗
PubMed2002

Antagonistic effects of Streptomyces violaceusniger strain G10 on Fusarium oxysporum f.sp. cubense race 4: indirect evidence for the role of antibiosis in the antagonistic process.

Fusarium oxysporum f.sp. cubense is the causal pathogen of wilt disease of banana. A cost-effective measure of control for this disease is still not available. Streptomyces violaceusniger strain G10 acts as an antifungal agent antagonistic towards many different phytopathogenic fungi, including different pathogenic races of the Fusarium wilt pathogen. In an attempt to understand the mode of action of this antagonist in nature, the interaction between S. violaceusniger strain G10 and F. oxysporum f.sp. cubense was first studied by paired incubation on agar plates. Evidence for the in vitro antibiosis of strain G10 was demonstrated by inhibition zones in the "cross-plug" assay plates. Microscopic observations showed lysis of hyphal ends in the inhibited fungal colonies. Culture of strain G10 in liquid media produces antifungal metabolites, which showed in vitro antagonistic effects against F. oxysporum f.sp. cubense such as swelling, distortion and excessive branching of hyphae, and inhibition of spore germination. An indirect method was used to show that antibiosis is one of the mechanisms of antagonism by which strain G10 acts against F. oxysporun f.sp. cubense in soil. This study suggests the potential of developing strain G10 for the biological control of Fusarium wilt disease of banana.

Agar↗
PubMed1992

WS9326A, a novel tachykinin antagonist isolated from Streptomyces violaceusniger no. 9326. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

Data from several studies suggest that tachykinins may play an important role in the pathophysiology of airway diseases, especially asthma. Our aim is to discover tachykinin antagonists which exhibit therapeutically useful anti-asthmatic activity. In our search for activities inhibiting the binding of [3H]substance P to guinea-pig lung membrane preparations, we have found that the fermentation product, WS9326A, isolated from Streptomyces violaceusniger, is a potent tachykinin receptor antagonist.

Animals↗
PubMed2006

Biocontrol of wood-rotting fungi with Streptomyces violaceusniger XL-2.

During the previous decade, chitinases have received increased attention because of their wide range of applications. Chito-oligomers produced by enzymatic hydrolysis of chitin have been of interest in recent years because of their broad applications in medical, agricultural, and industrial applications, such as antibacterial, antifungal, hypo cholesterolemic, and antihypertensive activity, and as food quality enhancer. Fungal cell walls being rich in chitin also enable the use of chitinases in biocontrol of fungal pathogens, as bio-fungicides. An actinomycete was isolated from the bark of trees of Dehradun in India and was later identified as Streptomyces violaceusniger. This strain exhibits strong antagonism towards various wood-rotting fungi, such as Phanerochaete chrysosporium, Postia placenta, Coriolus versicolor, and Gloeophyllum trabeum. Further, studies showed an extracellular bioactive compound was responsible for the antagonism. The conditions for the production of this biocontrol agent were optimized, and the effects of various stress factors (like nitrogen-deficient media, carbon-deficient media, etc.) were studied. The presence of chitin in the growth media was found to be an essential factor for the active production of the biocontrol agent. The pH and temperature optima for the biocontrol agent were determined. Purification and characterization of this specific biocontrol agent was performed through anion exchange chromatography using a DEAE-cellulose column, and a single protein band was obtained on a 10% sodium dodecyl sulfate-polyacrylamide gel. The protein was later identified as a 28 kDa endo chitinase by MALDI-TOF (matrix-assisted laser desorption ionization-time of flight) and by a chitobiose activity assay.

Antifungal Agents↗
PubMed1998

WA8242A1, A2 and B, novel secretary phospholipase A2 inhibitors produced by Streptomyces violaceusniger. III. Structure elucidation and total synthesis of WA8242B.

The structure of WA8242B, a potent novel inhibitor against phospholipase A2, was fully characterized by spectroscopic methods and chemical degradation. The success of total synthesis of WA8242B confirmed the structure and allowed the pharmacological study of WA8242B. The structures of WA8242A1 and A2 were also described.

Adipates↗
PubMed1992

WS9326A, a novel tachykinin antagonist isolated from Streptomyces violaceusniger no. 9326. II. Biological and pharmacological properties of WS9326A and tetrahydro-WS9326A (FK224)

WS9326A binds competitively to [3H]substance P (NK-1 receptor) binding sites on guinea-pig lung membranes (IC50 = 3.6 x 10(-6) M), and acts as a tachykinin antagonist in various functional assays. WS9326A inhibited tracheal constrictions produced by exogenously added substance P and neurokinin A, with IC50 values of 9.7 x 10(-6) M and 3.5 x 10(-6) M, respectively. WS9326A inhibited neurokinin A-induced bronchoconstriction in a dose dependent manner when administered to guinea-pigs intravenously together with neurokinin A, and was also effective in preventing capsaicin-induced bronchoconstriction, which is known to be caused by release of endogenous tachykinins (substance P and neurokinin A). FK224 (tetrahydro-WS9326A; catalytic hydrogenation of WS9326A gave FK224) was more potent than WS9326A in the [3H]substance P receptor binding assay using guinea-pig lung membrane (IC50 = 1.0 x 10(-7) M).

Animals↗
PubMed2005

Newly isolated Streptomyces spp. as enantioselective biocatalysts: hydrolysis of 1,2-O-isopropylidene glycerol racemic esters.

AIMS: To identify microbial strains with esterase activity able to enantioselectively hydrolyse esters of (R,S)-1,2-O-isopropylidene glycerol. METHODS AND RESULTS: The microbial hydrolysis of various racemic esters of 1,2-O-isopropylidene glycerol (IPG) was attempted by screening among Streptomyces spp. previously selected on the basis of their carboxylesterase activity. The best results were observed in the hydrolysis of butyrate ester and two strains appeared promising as they showed opposite enantioselectivity: Streptomyces sp. 90852 gave predominantly (S)-IPG, while strain 90930 mostly gave the R-alcohol. Streptomyces sp. 90930 was identified as Streptomyces violaceusniger, whereas Streptomyces sp. 90852 is a new species belonging to the Streptomyces violaceus taxon. The carboxylesterase belonging to strain 90852 gave a maximum value of enantiomeric ratio (E) of 14-16. This strain was lyophilized and used as dry mycelium for catalysing the synthesis of isopropylidene glycerol butyrate in heptane showing reaction rate and enantioselectivity (E = 6.6) lower than what observed for the hydrolysis. CONCLUSIONS: A new esterase with enantioselective activity towards (R,S)-IPG butyrate has been selected. The best enantioselectivity is similar or even better than the highest reported value in the literature with commercial enzymes. The enzyme is produced by a new species belonging to the S. violaceus taxon. SIGNIFICANCE AND IMPACT OF THE STUDY: New esterases from streptomycetes can be employed for the enantioselective hydrolysis of chiral esters derived from primary alcohols, not efficiently resolved with commercial enzymes.

Alkenes↗
PubMed2026

Streptomyces xingningensis sp. nov. and Streptomyces rhizosphaerae sp. nov. isolated from the rhizosphere soil of Camellia oleifera.

Two novel actinobacteria strains, designated YCB024T and YCB041T, were isolated from rhizosphere soil samples of Camellia oleifera collected from Xingning City, Guangdong Province, PR China. Both strains exhibited mycelial filaments and intertwined hyphal cells. Phylogenetic analysis revealed that strain YCB024T exhibited the highest 98.8% 16S rRNA gene similarity with Streptomyces yogyakartensis NBRC 100779T, Streptomyces javensis NBRC 100777T and Streptomyces violaceusniger NBRC 13459T, and strain YCB041T exhibited the highest 98.9% similarity with Streptomyces albospinus NBRC 13846T. The average nucleotide identities (ANI) and digital DNA-DNA hybridization (dDDH) values among the two strains and their closely related species indicated that they were clearly different from other known Streptomyces species. The draft genome sizes of the two strains were 6.9 Mbp and 9.5 Mbp with DNA G+C contents of 70.4 mol% and 71.7 mol%. The major cellular fatty acids in strain YCB024T included iso-C14 : 0, iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and C16 : 0, and strain YCB041T included iso-C15 : 0, anteiso-C15 : 0, iso-C16 : 0 and C16 : 0. The major polar lipids of the two strains were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol mannoside or unidentified aminophospholipid. The respiratory quinones of both strains included MK-9 (H6), MK-9 (H8) and MK-10 (H4). Based on phylogenetic analysis, ANI and dDDH values, physiological and chemical properties, strains YCB024T and YCB041T represent two novel species of the genus Streptomyces, for which the names Streptomyces xingningensis sp. nov. (type strain YCB024T=GDMCC 4.314T=JCM 36249T) and Streptomyces rhizosphaerae sp. nov. (type strain YCB041T=GDMCC 4.469T=JCM 38170T) are proposed, respectively.

Streptomyces↗
PubMed2003

Streptomyces yatensis sp. nov., a novel bioactive streptomycete isolated from a New-Caledonian ultramafic soil.

The taxonomic position of an actinomycete isolated from an ultramafic soil in New Caledonia was examined using a polyphasic approach. The organism, which was designated SFOCin 76, was found to have chemical and morphological properties typical of streptomycetes and formed a distinct phyletic line in the Streptomyces violaceusniger clade of the 16S rDNA tree. It also showed a unique pattern of phenotypic properties that distinguished it from representatives of all of the validly described species classified in this clade. It is, therefore, proposed that strain SFOCin 76 be classified in the genus Streptomyces as Streptomyces yatensis sp. nov.

Anti-Bacterial Agents↗