土壤放线菌Streptomyces sp．2215代谢物的分离鉴定及抗肿瘤活性研究

土壤来源的放线菌Streptomyces sp.2215 经发酵罐发酵,培养液经乙酸乙酯提取,硅胶柱层析、C18反相色谱、Sephadex LH-20、及TLC 和HPLC分离纯化得到四个化合物,并通过理化性质,IR,FAB-MS,1H,13C NMR,1H-1HCOSY,HSQC,HMBC等鉴定为单亚砜棘霉素(monosulfoxide quinomycine,1)、棘霉素(echinomycin,2)、喹喔啉-2-羧酸(3)、十六烷酸(4).其中化合物1、2经MTT法测定体外对K562细胞具有抑制活性,其IC50值分别为34.0、1.5 ng/mL.     

Streptomyces daliensis sp. nov. from soil

A novel actinomycete strain YIM 31724^T was isolated from a soil sample collected from Dali, Yunnan Province, People’s Republic of China. The strain is characterized by white to yellow white aerial mycelia, spiral spore chains and smooth spore surface. The cell wall of strain YIM 31724^T contained LL-diaminopimelic acid (A₂pm) and traces of meso-A₂pm. Whole-cell hydrolysates contained mainly glucose and small amounts of galactose and xylose. The menaquinones were MK-9(H₆) (31%) and MK-9(H₈) (69%). Phosphatidylethanolamine was the diagnostic phospholipid. The DNA G+C content of strain YIM 31724^T was 67.2 mol%. Phylogenetic analysis indicated that the strain belongs to the genus Streptomyces, with highest similarity to Streptomyces rimosus subsp. rimosus JCM 4667^T (rRNA gene sequence similarity value of 98.9%) and Streptomyces erumpens DSM 40941^T (rRNA gene sequence similarity value of 98.7%). Based on its phenotypic and genotypic characteristics, including low DNA–DNA hybridization results, strain is proposed as the type strain of a novel species, Streptomyces daliensis sp. nov.     

Iromycins from Streptomyces sp. and from synthesis: new inhibitors of the mitochondrial electron transport chain

Two new alpha-pyridone metabolites, iromycins E and F, were isolated from cultures of strain Streptomyces sp. Dra 17, thus expanding the recently discovered iromycin family. The inhibitory potential on the mitochondrial respiratory chain was examined and revealed that iromycin metabolites block NADH oxidation in beef heart submitochondrial particles with different efficacy, yet remarkably show only very low cytotoxicity. Difference spectroscopic studies indicated that iromycins inhibit the electron transport at the site of complex I (NADH-ubiquinone oxidoreductase). Derivatives of the natural products were semisynthetically prepared and provided detailed insights into structure-activity relationships. Drawn from these results, there are strong similarities with the piericidins, which are among the most potent complex I inhibitors of the mitochondrial electron transport chain. Furthermore, total synthesis afforded new analogues, and the non-natural iromycin S (IC50 = 58 ng/mL) emerged as the most active compound, thus opening avenues of future studies with the iromycins as new valuable biochemical tools.     

Identification of the gene cluster involved in muraymycin biosynthesis from Streptomyces sp. NRRL 30471

Muraymycin, a potent translocase I inhibitor with clinical potential, is produced by Streptomyces sp. NRRL 30471. The structure of muraymycin is highly unusual and contains the hexahydro-2-imino-4-pyrimidylglycyl moiety (epicapreomycidine) and an ureido bond. Here we report the identification of the muraymycin gene cluster from Streptomyces sp. NRRL 30471. Sequencing analysis of a 43.4-kb contiguous region revealed 33 ORFs, 26 of which were proposed to be involved in muraymycin biosynthesis. Independent targeted inactivation of mur16 and mur17 directly abolished muraymycin production, demonstrating the role of the genes essential for muraymycin biosynthesis. These data provide insights into the molecular mechanisms for muraymycin biosynthesis, and lay a foundation for the generation of muraymycin derivatives with enhanced bioactivity via the strategies of combinatorial biosynthesis.     

Identification and characterization of a highly alkaline and thermotolerant novel xylanase from Streptomyces sp.

Xylanases constitute an important industrial enzyme, which hydrolyzes the polysaccharide xylan. In this work, a novel Streptomyces strain producing cellulase-free xylanase was isolated from the soil samples collected from the mangrove forest of Kadalundi, Kerala, India. The strain produced unique enzyme, which exhibited optimal activity at pH 9.0 and tolerance up to pH 12.0. Media engineering was carried out to improve the enzyme production, which showed best enzyme production at 30°C, medium pH 9.0 and incubation time of 48 h. Enzyme was highly thermo-tolerant up to 70°C and alkaline tolerant. Partial gene amplification as well as partial purification of enzyme was carried out to characterize the enzyme. The unique features of the enzyme make it an ideal candidate for industrial application for paper and pulp industry.     

链霉菌HS-HY-045抗肿瘤代谢产物的研究

从链霉菌Streptomyces sp.HS-HY-045的发酵代谢产物中分离得到5个对小鼠淋巴瘤细胞系P388D有抑制作用的化合物,通过波谱分析它们分别鉴定为(-)-(2R,4S)-4-hydroxy-2-methoxy-2-(9E-pentenyl)-tetrahydropy-ran(1),Streptenol C(2),36074-11(3),Fujianmycin A(4)和Streptenol A(5),其中化合物3为新化合物。进一步使用人肺腺癌细胞系A549对5个化合物的抗肿瘤活性进行测试表明化合物4表现出较好的抑制作用,其IC50值为5.2μM。     

内生链霉菌Streptomyces sp.Ly221的次生代谢成分

从云南美登木茎皮组织分离得到内生菌Ly221,经16SrDNA部分核酸序列鉴定该菌属于链霉菌属（Streptomyces）。从其液体发酵提取物中分离得到5个化合物,经波谱分析鉴定其结构分别为：4,10-dihydroxy-10-methyl-dodee-2-en-1,4-olide（1）、两个非对映异构体4,11-dihydroxy-10-methyldodec-2-ell-1,4-olides（2／3）、4-hy-droxy-10-methyl-11-oxo-dodec-2-ell-1,4-olide（4）和N—aeetyltyramine（5）。     

Characterization and molecular cloning of thermostable alpha-amylase from Streptomyces sp.To1

Summary A new thermophilic Streptomyces sp. TO1, isolated from Tunisian soil, produced a thermostable alpha-amylase and pullulanase. The gene encoding for the alpha-amylase activity was cloned into the multicopy cloning plasmid pLM1 using S. lividans ZX1 as host strain. The ZX1 / pLM1 strain has the same activity than the initial TO1 strain and about 25 fold higher activity than the ZX1 strain. This alpha-amylase has an optimum of pH and temperature at 6 and 70 °C respectively.     

Streptomyces erringtonii sp. nov. and Streptomyces kaempferi sp. nov., isolated from a hay meadow soil

Two filamentous actinomycetes isolated from a hay meadow soil were provisionally assigned to the genus Streptomyces based on morphological features. The isolates were found to have chemical and morphological properties typical of the genus Streptomyces and formed distinct phyletic lines in the 16S rRNA gene tree. Isolate I36^T was most closely related to Streptomyces glauciniger NBRC 100913^T and isolate I37^T to Streptomyces mirabilis NBRC 13450^T. Low DNA:DNA relatedness values were recorded between each of the isolates and their closest phylogenetic neighbour. The isolates were also distinguished from their nearest phylogenetic neighbour, and from one another, using a combination of phenotypic properties. These data indicate that the isolates should be recognised as new species in the genus Streptomyces. The names proposed for these new taxa are Streptomyces erringtonii sp. nov. and Streptomyces kaempferi sp. nov. with isolate I36^T (=CGMCC 4.7016^T = KACC 15424^T) and isolate I37^T (=CGMCC 4.7020^T = KACC 15428^T) as the respective type strains.     

Anthraquinone glycosides from marine Streptomyces sp. strain

Two new anthraquinone glycosides Strepnoneside A (1) and Strepnoneside B (2), together with Chromomycin A₃ (3), were isolated from cultures of the marine Streptomyces sp. strain. The structures were elucidated on the basis of NMR spectroscopic and mass spectrometry data. Compound 3 exhibited cytotoxic activities against HCT 116 cell lines (IC₅₀ = 300 ± 11 pM).     

An alkaline and metallo-protein type endo xylanase from Streptomyces sp. CSWu-1

An alkaline xylanase (XynWu-1) from Streptomyces sp. CSWu-1 was isolated from the Korean soil sample, purified and biochemically characterized. The extracellular xylanase was purified 4.8 fold with a 16% yield using Sephadex G-50 followed by DEAE-Sepharose (fast flow) column chromatography. The molecular mass of the enzyme was approximately 37 kDa estimated by SDS-PAGE and xylan zymography. N-terminal amino acid sequence of XynWu-1 was AINVLVAALX. The enzyme was found to be stable in a broad range of pH (7.0 ～ 13.0) and to 50°C and have an optimal pH and temperature of 11.0 and 60°C, respectively. XynWu-1 activity was found to be affected by Mn²⁺ ion with highest activity at 6 mM and produced xylose, xylobiose, and xylotetraose as major hydrolyzed end products. It was found to degrade agro waste materials like corncob and wheat bran by XynWu-1 (2,000 U/g) as shown by electron microscopy. As being stable in extreme alkaline pH, diverse peculiar biochemical characteristics, and ability to produce oligosaccharide shows that XynWu-1 has potential application in various bioindustries like probiotics, ethanol, etc.     

Characterization of a xylanolytic complex from Streptomyces sp.

Streptomyces sp. DSM 41796 produced four major extracellular xylanases with Mr of 145, 120, 60 and 45 kDa. Those of 145 and 60 kDa formed a heterodimer. All xylanases, except that of 120 kDa, were induced by xylose, d-arabinose or sucrose, while commercial xylans induced the 60 kDa xylanase in a major proportion than others, and sugar-cane bagasse pith or lemon peel induced predominantly the 45 kDa xylanase.     

Classification of novel soil streptomycetes as Streptomyces aureus sp. nov., Streptomyces laceyi sp. nov. and Streptomyces sanglieri sp. nov

The taxonomic positions of soil isolates known as Streptomyces groups A, B and C were clarified. Comparative 16S rDNA sequence studies indicated that representatives of all three taxa formed distinct phyletic lines within the Streptomyces tree though the group A strains were shown to be related to Streptomyces griseus and associated validly described species. The taxonomic integrity of all three groups was highlighted by DNA:DNA relatedness and ribotype data though the group A strains encompassed a higher degree of genetic variation than the group B and C strains. In light of these and earlier phenotypic data it is proposed that Streptomyces groups A, B and C be given species status as Streptomyces sanglieri sp. nov., Streptomyces aureus sp. nov. and Streptomyces laceyi sp. nov., respectively. This revised version was published online in June 2006 with corrections to the Cover Date.     

Identification of neomacrophorins isolated from Trichoderma sp. 1212-03 as proteasome inhibitors

Neomacrophorins I-III (1–3) and X have previously been isolated from Trichoderma sp. 1212-03. Their mode of action against cancer cells and the mechanism of biosynthesis of the characteristic [4.4.3] propellane framework in neomacrophorin X have not been reported. The isolation and characterization of neomacrophorins IV (4), V (5), and VI (6) is reported. Epoxyquinones 1, 4, and 6 potently induced apoptotic cell death in human acute promyelocytic leukemia HL60 cells, while epoxysemiquinols 2, 3, and 5 showed weak activity. This indicates that the epoxyquinone moiety is crucial for apoptosis-inducing activities of neomacrophorins. We also found that neomacrophorins inhibit proteasome in vitro, and 1, 4, and 6 induced significant accumulation of ubiquitinated proteins in HL60 cells. These activities were completely suppressed by a nucleophile, N-acetyl-l-cysteine (NAC). The analysis of reaction mechanisms using LC-MS suggested that C2′ and C7′ of neomacrophorins could be Michael acceptors in the reaction with NAC methyl ester (NACM). These findings indicated that the electrophilic properties of neomacrophorins are responsible for both their potent biological effects and the biosynthesis of unique [4.4.3] propellane framework in neomacrophorin X.     

Protease inhibitors from Streptomyces violascens

Summary Two protease inhibitors from the culture fluid of Streptomyces violascens U 10600 have been purified with a method including freeze-drying, methanol extraction, dialysis, and ultrafiltration. By gel filtration on Sephadex G-15 a separation in two active inhibitors, one of trypsin and one of chymotrypsin, was made.The inhibitors were stable at 100°C, pH 5, for 20 min and at 24°C between pH 1.8 to 9.7. Both inhibitors were dialysable. They had no bacteriostatic or fungistatic effects. The trypsin inhibitor inhibited also papain and proteases from Aspergillus oryzae, Alternaria tenuissima, Entomophthora coronata, and to some extent Gibberella fujikuroi, but not chymotrypsin, kallikrein, ficin, or pepsin. The chymotrypsin inhibitor inhibited also papain and proteases from Aspergillus oryzae, Alternaria tenuissima, and Gibberella fujikuroi, but not trypsin, kallikrein, ficin, pepsin, or protease from Entomophthora coronata.     

Protease inhibitors from Streptomyces violascens

Summary Production of protease inhibitors from Streptomyces violascens U 10 600 was studied in quiescent flasks, shake flasks, and fermentors. A starting pH in the medium between pH 6 and 7 was the most favourable for the process. Both trypsin and chymotrypsin inhibitors were produced. Maximum inhibitor activity was attained after 3 days of cultivation in a protein powder medium at 18°C with pH control to pH 5 during the latter part of the process.     

Blood Group Substance-degrading Enzymes Obtained from Streptomyces sp.

The blood group B substance-degrading activity of Streptomyces 9917S₂ is induced by galactosides as α-galactosidase activity is. Purification of the α-galactosidase was attempted by chromatography on DEAE-Sephadex and Sephadex. The purified preparation was shown to be free from α- and β-glucosidases, β-galactosidase, α- and β-glucosaminidases, and α- and β-galactosaminidases activities. The blood group B substance-degrading activity was present only in this fraction. This enzyme preparation cleaves α-(1→3)- and α-(1→6)-galactosidic linkages. The activity is inhibited by d-galactose, melibiose, and raffinose and also by l-arabinose and d-xylose.     

Quinazolinone alkaloids from actinomycete Streptomyces sp. BCC 21795

Four quinazolinones, new naturally occurring 1 and three known derivatives 2–4, along with previously synthesized 4-phenylbut-3-enamide (5) and three known compounds, 2-acetamido benzamide, 1H-indole-3-carbaldehyde, and 2-phenylacetamide, were isolated from an actinomycete, Streptomyces sp. BCC 21795. The structures were elucidated based on the analysis of NMR spectroscopic and mass spectrometric data. Compound 1 exhibited strong cytotoxic activity to Vero cells with IC₅₀ 3.30 μg/mL.     

Secondary metabolites from endophytic Streptomyces sp. Lz531

From the branch tissue of Maytenus hookeri, the endophytic strain Lz531 was isolated, and determined to belong to Streptomyces, according to its 16S rRNA sequence. From the extracts of the fermentation broth of Streptomyces sp. Lz531, two new and four known compounds were isolated. The two new compounds were identified as cyclo(L-Pro-L-Val-L-Val) (1) and 13-methyl-N-(2-phenylethyl)tetradecanamide (2).