Karamomycins A-C: 2-Naphthalen-2-yl-thiazoles from Nonomuraea endophytica.

Karamomycins A-C (2-4), the first natural 2-naphthalen-2-yl-thiazole derivatives, were isolated along with a plausible precursor molecule, 1-hydroxy-4-methoxy-2-naphthoic acid (1), uracil, 1-acetyl-ß-carboline, and actinomycin C2 from the culture broth of the terrestrial actinomycete strain GW58/450, identified as Nonomuraea endophytica. These compounds were characterized by analysis of their NMR and mass spectrometry (MS) data; the absolute configurations of 2 and 4 were determined by comparison of 13C NMR, NOESY, and circular dichroism (CD) spectra with density functional theory (DFT)-calculated data. In karamomycin C (4), the thiazole of 2 is connected to an unusual iminothiazolo[4,3- c][1,4]thiazepinone, for which we proposed a biosynthetic origin from two cysteine residues. It is closely related to ulbactin F; however, the heterocycle is enantiomeric to the latter and connected to phenol instead of 4-methoxy-1-naphthol. Karamomycins A (2) and C (4) were cytotoxic.

Isolation and Structural Elucidation of Nitrogenous Secondary vetabolites from Terrestrial and Marine Streptomyces spp.

Screening and chromatography of extracts from a terrestrial and a marine-derived streptomycete yielded two new nitrogenous benzene derivatives, namely (S)-N-[3-hydroxy--(4-hydroxyphenyl)-propyl]-acetamide (1a), and (R)-2-(l-methyl-2-oxopropylamino)-benzoic acid (2). Additionally, eight known compounds were. isolated, 2-acetamidophenol, phenazine-l-carboxylic acid, phenazine-l-carboxylic acid methyl ester, perlolyrin, tyrosol, uracil, and anthranilic acid. The structures of the new compounds were deduced from high resolution mass, ID and 2D NMR spectra and by comparison with related compounds from the literature. The absolute configuration of ia and 2 was determined by comparison of experimental and calculated CD and ORD data.

Streptosporangium sandarakinum sp. nov.

A Gram-positive, non-spore-forming bacterium (GW-12028(T)) of unknown origin showing filamentous growth and producing spherical sporangia was studied for its taxonomic allocation. The 16S rRNA gene sequence analysis and subsequent similarity studies showed that strain GW-12028(T) belongs to the genus Streptosporangium, and is most closely related to Streptosporangium pseudovulgare DSM 43181(T) (99.9 %) and Streptosporangium nondiastaticum DSM 43848(T) (99.6 %) and more distantly related to Streptosporangium fragile IFO 14311(T) (98.4 %) and other species of the genus Streptosporangium (95.8 to 98 %). Chemotaxonomic analyses showed that the peptidoglycan diamino acid was meso-diaminopimelic acid. Whole-cell hydrolysates contained madurose as the diagnostic sugar and exhibited a quinone system that contained predominantly menaquinones with nine isoprenoic units in the side chain [MK-9, MK-9(H2), MK-9(H4)]. The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phoshatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol-mannosides, four unidentified glycolipids, a phospholipid and an aminolipid. The polyamine pattern contained the major compounds spermine and spermidine. The major fatty acids were 10-methyl C17 : 0, iso-C16 : 0 and C15 : 0. These chemotaxonomic traits are common to other species of the genus Streptosporangium. DNA-DNA hybridizations and physiological and biochemical tests in comparison with the type strains of the most closely related species, S. nondiastaticum and S. pseudovulgare, allowed genotypic and phenotypic differentiation of strain GW-12028(T). This strain represents a novel species, for which we propose the name Streptosporangium sandarakinum sp. nov., with the type strain GW-12028(T) ( = LMG 27062(T) = DSM 45763(T)).

Nocardia grenadensis sp. nov., isolated from sand of the Caribbean Sea.

A Gram-stain-positive, non-spore-forming bacterium (GW5-5797(T)) was isolated on soil extract agar from sand collected at a depth of 5 m in the Caribbean Sea near Grenada. 16S rRNA gene sequence analysis and similarity studies showed that strain GW5-5797(T) belongs to the genus Nocardia, and is most closely related to Nocardia speluncae N2-11(T) (99.2% similarity) and Nocardia jinanensis 04-5195(T) (99.2%) and more distantly related to Nocardia rhamnosiphila 202GMO(T) (98.6%) and other Nocardia species. Strain GW5-5797(T) could be distinguished from all other recognized Nocardia species by sequence similarity values less than 98.5%. The peptidoglycan diamino acid was meso-diaminopimelic acid. Strain GW5-5797(T) exhibited a quinone system with the predominant compounds MK-8(H(4)ω-cyclo) and MK-8(H(2)). The polar lipid profile of GW5-5797(T) consisted of the major compounds diphosphatidylglycerol, phosphatidylethanolamine and an unidentified glycolipid, moderate amounts of phosphatidylinositol and a phosphatidylinositol mannoside and minor amounts of several lipids including a second phosphatidylinositol mannoside. The polyamine pattern contained the major compound spermine and moderate amounts of spermidine. The major fatty acids were C(16:0,) C(18:1)ω9c and 10-methyl C(18:0). These chemotaxonomic traits are in excellent agreement with those of other Nocardia species. The results of DNA-DNA hybridizations and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain GW5-5797(T) from the most closely related species, showing 16S rRNA gene sequence similarities >98.5%. Strain GW5-5797(T) therefore merits separate species status, and we propose the name Nocardia grenadensis sp. nov., with the type strain GW5-5797(T) (=CCUG 60970(T) =CIP 110294(T)).

Nonomuraea rosea sp. nov.

A Gram-positively staining, aerobic, non-motile actinomycete, strain GW 12687(T), that formed rose-pigmented colonies and branched substrate and aerial mycelia was studied in detail for its taxonomic position. On the basis of 16S rRNA gene sequence similarity studies, strain GW 12687(T) was grouped into the genus Nonomuraea, being most closely related to Nonomuraea dietziae (97.6 %), Nonomuraea africana (97.1 %), and Nonomuraea kuesteri (97.1 %). The 16S rRNA gene sequence similarity to other species of the genus Nonomuraea was < or =97 %. The chemotaxonomic characterization supported allocation of the strain to the genus Nonomuraea. The major menaquinone was MK-9(H(4)) with minor amounts of MK-9(H(2)), MK-9(H(6)), MK-9(H(0)) and MK-8(H(4)). The polar lipid profile contained the major compound diphosphatidylglycerol, moderate amounts of phosphatidylmonomethylethanolamine, phosphatidylethanolamine, hydroxy-phosphatidylethanolamine, hydroxy-phosphatidylmonomethylethanolamine, and an unknown aminophosphoglycolipid. Phosphatidylinositol mannosides and phosphatidylinositol were also present. The major fatty acids were iso- and anteiso- and 10-methyl-branched fatty acids. The results of physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain GW 12687(T) from closely related species. Thus, GW 12687(T) represents a novel species of the genus Nonomuraea, for which the name Nonomuraea rosea sp. nov. is proposed, with GW 12687(T) (=DSM 45177(T) =CCUG 56107(T)) as the type strain.

An imidazopyridinone and further metabolites from streptomycetes.

Screening and chromatographic analysis of the extracts from the terrestrial streptomycete GW5127 and from the marine Streptomyces sp. isolate B7967 yielded four new metabolites, i.e. 8-ethyl-6,11-dihydroxy-l1-methoxy-naphthacene-5,12-dione (la), 4-acetyl-1,3-dihydro-imidazo[4,5-c]pyridin-2-one (4a), 5-hydroxmethyl-4-hydroxy-2,4-dimethyl-2-cyclopentenone (6), and N-[2-(3'-hydroxy-4'-methoxyphenyl)-ethyl]-acetamide (5a), along with five known compounds, beta-rubromycin (2), rubromycin (3), 2-(3'-hydroxy-4'-methoxyphenyl)ethanol (5b), uracil, and N-acetyltyramine. The structures of the new compounds were deduced from high resolution mass, 1D and 2D NMR spectra and by comparison with related compounds from the literature. The antibiotic activity of the crude extracts was due to 2 and 3.

Streptomyces specialis sp. nov.

A Gram-positive, non-endospore-forming bacterium (GW41-1564(T)) was isolated from soil. Comparison of 16S rRNA gene sequences showed that strain GW41-1564(T) is a member of the genus Streptomyces, exhibiting highest similarities with Streptomyces hainanensis YIM 47672(T) (97.8 %) and Streptomyces cacaoi subsp. cacaoi NBRC 12748(T) (97.5 %). Strain GW41-1564(T) could be distinguished from any other Streptomyces species with validly published names by sequence similarity values less than 97.5 %. Strain GW41-1564(T) exhibited an unusual quinone system, with the predominant compounds MK-10(H(4)) and MK-10(H(6)) and smaller amounts of MK-9(H(4)) and MK-9(H(6)). The type strain of the most closely related species, S. hainanensis YIM 47672(T), also contained an unusual quinone system composed of MK-9(H(6)) and MK-9(H(8)) in addition to MK-9(H(4)) and MK-10(H(0)), whereas the type strain of the second most closely related species, S. cacaoi NBRC 12748(T), contained a quinone system, composed of MK-9(H(6)) and MK-9(H(8)), typical of Streptomyces. The polar lipid profile of GW41-1564(T) consisted of the predominant compound diphosphatidylglycerol, moderate amounts of phosphatidylethanolamine, phosphatidylglycerol and phosphatidylinositol and minor to trace amounts of two phosphatidylinositol mannosides and several unknown lipids, and the major fatty acids were iso-C(16 : 0,) anteiso-C(17 : 1)omega9c and anteiso-C(17 : 0). The results of physiological and biochemical tests allowed further phenotypic differentiation of strain GW41-1564(T) from the related species S. hainanensis. Strain GW41-1564(T) clearly merits species status, and we propose the name Streptomyces specialis sp. nov., with the type strain GW41-1564(T) (=DSM 41924(T) =CCM 7499(T)).

Furan oligomers and beta-carbolines from terrestrial streptomycetes.

2,5-Bis(hydroxymethyl)furan monoacetate (3) and 2,5-bis(hydroxymethyl)furan diacetate (4) were obtained as new natural products from an ethyl acetate extract of the terrestrial Streptomyces sp. isolate GW11/1695. Another Streptomyces isolate, GW21/1313, delivered a dimer (6) and a trimer (7) of (hydroxymethyl)furfural. The latter strain also produced 4-hydroxy-2-(5-(hydroxymethyl)furan-2-ylmethylene)-5-methylfuran-3-one (5), perlolyrin (8), and two new beta-carboline derivatives, 9 and 10. 2,5-Bis(hydroxymethyl)furan diacetate (4) exhibited weak cytotoxic activity against brine shrimp larvae.

Julichrome Q6 glucuronide, a monomeric subunit of the julimycin B-I complex from a terrestrial Streptomyces sp.

The terrestrial Streptomyces sp. isolate GW6225 afforded julichrome Q 6 glucuronide ( 9), the first monomeric member of the julimycin-B complex, and additionally the julichromes Q 1.2 ( 7a), Q 1.5 ( 7b), and Q 3.5 ( 8), which were fully characterized by 2D NMR spectra. Additional new microbial compounds were 4-acetylchrysophanol ( 6a) and N-phenyl-beta-naphthylamine ( 10). The isomeric N-phenyl-alpha-naphthylamine ( 11) was found in the marine Streptomyces sp. B8335 and was also characterized. The high antibiotic activity of Streptomyces sp. GW6225 extracts was probably due to the thiazolyl cyclopeptide nosiheptide.

Nocardia acidivorans sp. nov., isolated from soil of the island of Stromboli.

A Gram-positive, non-spore-forming bacterium (strain GW4-1778(T)) was isolated from soil of the Italian island of Stromboli. 16S rRNA gene sequence similarity studies showed that strain GW4-1778(T) is a member of the genus Nocardia, most closely related to Nocardia pseudobrasiliensis (GenBank accession no. DQ659914; 98.6 %), Nocardia nova (Z36930; 98.6 %), Nocardia niigatensis (AB092563; 98.4 %), Nocardia jiangxiensis (AY639902; 98.0 %), Nocardia uniformis (Z46752; 98.0 %) and Nocardia miyunensis (AY639901; 97.8 %). Strain GW4-1778(T) could be distinguished from any other established Nocardia species by sequence similarity values of less than 97.5 %. Strain GW4-1778(T) exhibited a quinone system with the predominant compound MK-8 (H(4), omega-cycl) (99.5 %) and traces of MK-8 (H(4)), characteristic for the genus Nocardia. The polar lipid profile of strain GW4-1778(T) consisted of the predominant compound diphosphatidylglycerol, moderate amounts of phosphatidylethanolamine, phosphatidylinositol, two phosphatidylinositol mannosides, a unknown polar lipid and trace amounts of two unknown lipids and the major fatty acids were C(15 : 0), C(16 : 0), C(17 : 1)omega8c and 10-methyl C(17 : 0). The results of DNA-DNA hybridizations and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain GW4-1778(T) from related species with 16S rRNA gene similarities of >97.5 %. Therefore, strain GW4-1778(T) merits species status, for which the name Nocardia acidivorans sp. nov. is proposed, with the type strain GW4-1778(T) (=CCUG 53410(T)=CIP 109315(T)=DSM 45049(T)).

Actinoplanes couchii sp. nov.

A Gram-positive bacterium, strain GW8-1761(T), was isolated from soil close to the Marmore waterfalls, Terni, Italy. 16S rRNA gene sequence similarity studies showed that strain GW8-1761(T) belonged to the genus Actinoplanes, being most closely related to Actinoplanes italicus JCM 3165(T) (98.9 %), A. rectilineatus IFO 13941(T) (98.5 %), A. palleronii JCM 7626(T) (97.8 %), A. utahensis IFO 13244(T) (97.6 %) and A. cyaneus DSM 46137(T) (97.6 %). Strain GW8-1761(T) could be distinguished from any other Actinoplanes species with validly published names by 16S rRNA gene sequence similarity values of less than 97.5 %. Chemotaxonomic data [major menaquinone MK-9(H(4)); major polar lipids diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol, with phosphatidylcholine and aminoglycolipids absent; major fatty acids C(15 : 0), C(16 : 0), C(16 : 0) iso, C(17 : 1)omega8c and summed feature 3 (C(16 : 1)omega7c and/or C(15 : 0) iso 2-OH)] supported the affiliation of strain GW8-1761(T) to the genus Actinoplanes. The results of DNA-DNA hybridizations and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain GW8-1761(T) from the most closely related species. Strain GW8-1761(T) therefore merits species status, and we propose the name Actinoplanes couchii sp. nov., with the type strain GW8-1761(T) (=DSM 45050(T)=CIP 109316(T)).

Oxachelin, a novel iron chelator and antifungal agent from Streptomyces sp. GW9/1258.

During a screening campaign for new antimicrobial and antifungal secondary metabolites from several thousand actinomycetes, a novel compound, isolated by activity guided fractionation, was oxachelin (1) from the new Streptomyces sp. GW9/1258. Oxachelin shows strong antibiotic activities against several fungi and Gram(+) bacteria. Additionally, oxachelin is a strong complexing ligand for Fe3+ (siderophore), possibly making it useful e.g. for iron excess diseases.

Kettapeptin: isolation, structure elucidation and activity of a new hexadepsipeptide antibiotic from a terrestrial Streptomyces sp.

The ethyl acetate extract of the Streptomyces sp. isolate GW99/1572 exhibited significant biological activity against Gram-positive bacteria and delivered kettapeptin (1), a new hexadepsipeptide antibiotic of the azinothricin type. The structure was elucidated by various 1D and 2D NMR techniques, mass spectrometry and by comparison of the NMR data with those of closely related antibiotics. The absolute configuration of the compound was derived by crystal structure analysis and by comparison with the optical rotation data of related compounds.

Sorbicillin analogues and related dimeric compounds from Penicillium notatum.

In our screening of microorganisms for new natural products, the fungus Penicillium notatum delivered further members of the sorbicillin family, namely, the sohirnones A [3, 1-(2,4-dihydroxy-5-methylphenyl)hex-4-en-1-one], B [4a, 1-(2,4,5-trihydroxy-3,6-dimethylphenyl)hexa-2,4-dien-1-one], and C [5, 1-(2,4,5-trihydroxy-3,6-dimethylphenyl)hex-4-en-1-one]. A stable tautomer of oxosorbicillinol (7) was characterized as 6, and the recently described 7-deacetoxyyanuthone (8) was reisolated. The additionally isolated rezishanones A-D (12-13c) are the first natural Diels-Alder products of sorbicillinol (1) with dienophiles not related with 1. The monomers and dimers showed weak antibacterial activity, but were inactive against fungi and algae. The structures were determined by spectroscopic methods and by comparison of the NMR data with those of the structurally related 2',3'-dihydrosorbicillin (2) and, in the case of 4a, by transformation into the known sorrentanone (4b).

Nonomuraea kuesteri sp. nov.

A Gram-positive, aerobic, non-motile actinomycete, strain GW 14-1925(T), that formed branched substrate and aerial mycelium was studied using a polyphasic approach. On the basis of 16S rRNA gene sequence similarity studies, strain GW 14-1925(T) was shown to belong to the genus Nonomuraea, being most closely related to Nonomuraea longicatena (97.9 %), Nonomuraea turkmeniaca (98.9 %), Nonomuraea helvata (98.6 %), Nonomuraea polychroma (98.5 %), Nonomuraea salmonaea (98.3 %), Nonomuraea roseoviolacea subsp. roseoviolacea (98.1 %) and Nonomuraea roseoviolacea subsp. carminata (97.7 %). The 16S rRNA gene sequence similarity to other Nonomuraea species was <97.5 %. Chemotaxonomic data [major menaquinones of the MK-9 series with minor amounts of MK-8(H(4)); major polar lipids of phospholipid type IV; fatty acids with major amounts of iso- and anteiso- and 10-methyl-branched fatty acids in combination with iso-branched 2-hydroxy fatty acids] supported allocation of the strain to the genus Nonomuraea. The results of DNA-DNA hybridizations and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain GW 14-1925(T) from closely related species; thus, GW 14-1925(T) represents a novel species of the genus Nonomuraea, for which the name Nonomuraea kuesteri sp. nov. is proposed, with GW 14-1925(T) (=DSM 44753(T)=NRRL B-24325(T)) as the type strain.

Quinazolin-4-one derivatives from Streptomyces isolates.

From the ethyl acetate extract of the strain Streptomyces sp. isolate GW23/1540, besides 16 known products, several 1H-quinazolin-4-one derivatives were isolated. (SR)-2-(1-Hydroxyethyl)-2-methyl-2,3-dihydro-1H-quinazolin-4-one (4) and (RR)-2-(1-hydroxyethyl)-2-methyl-2,3-dihydro-1H-quinazolin-4-one (5) are new natural products. 2-Methyl-3H-quinazolin-4-one (2) and 1H-quinazoline-2,4-dione (3) are known from other bacteria and plants, respectively. From another Streptomyces sp., GW2/577, 5-methyl-1H-quinazoline-2,4-dione (6) was isolated and the structure proven by comparison with the isomeric 7. The new natural products showed no activity against the microalgae Chlorella vulgaris, Chlorella sorokiniana, and Scenedesmus subspicatus, the fungus Mucor miehei, the yeast Candida albicans, and the bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Streptomyces viridochromogenes.

Nocardia tenerifensis sp. nov.

A Gram-positive, non-spore-forming bacterium (GW39-1573(T)) was isolated from soil of the Spanish island of Tenerife. 16S rRNA gene sequence similarity studies showed that strain GW39-1573(T) belonged to the genus Nocardia and was most closely related to Nocardia brasiliensis (98.0 %), Nocardia beijingensis (97.3 %), Nocardia transvalensis (97.5 %), Nocardia asteroides (97.2 %) and Nocardia farcinica (97.0 %). Strain GW39-1573(T) could be distinguished from all other validly described Nocardia species by sequence similarity values of less than 97 %. Chemotaxonomic data [major menaquinone: MK-8(H(4, omega-cycl)); major polar lipids: diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylinositol, phosphatidylinositol mannoside and an unknown glycolipid and an unknown phospholipid; major fatty acids: C(16 : 0), C(18 : 1)omega9c and 10 methyl C(16 : 0)] and the presence of mycolic acids supported the affiliation of strain GW39-1573(T) to the genus NOCARDIA: The results of DNA-DNA hybridizations and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain GW39-1573(T) from those related species that showed 16S rRNA gene sequence similarity values of greater than 97 %. Strain GW39-1573(T) merits species status, and the name Nocardia tenerifensis is proposed with the type strain GW39-1573(T) (=DSM 44704(T)=CIP 107929(T)).

Seitomycin: isolation, structure elucidation and biological activity of a new angucycline antibiotic from a terrestrial Streptomycete.

A new antibiotic, named seitomycin (1c), and the known microbial metabolite tetrangulol methyl ether (2) were found in the ethyl acetate extract of two terrestrial Streptomyces sp. isolates. The structure of the new antibiotic was elucidated by spectroscopic studies and by comparison of the NMR data with the structurally related hatomarubigin C (1a) and SM-196 B (1b). Seitomycin (1c) showed moderate antimicrobial and weak phytotoxic activity, similar to tetrangulol methyl ether (2).

Isolation, structure elucidation and biological activity of 8-O-methylaverufin and 1,8-O-dimethylaverantin as new antifungal agents from Penicillium chrysogenum.

In the screening of fungi for bioactive components, 8-O-methylaverufin (1b) and 1,8-O-dimethylaverantin (2b) were isolated from the culture broth of Penicillium chrysogenum. The structure of these new antibiotics were determined by interpretation of the 1D and 2D NMR spectra and by comparison of the NMR data with those of the structurally related averufin (1a) and averantin (2a). Both compounds have moderate antifungal activity.