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Hartmut Laatsch

Publications and source records attributed to Hartmut Laatsch.

At least 37 records · Page 2Linked to original sources
PubMed2004

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.

Bacillus subtilis↗
PubMed2004

An acetoxygenated analogue of ergosterol from a soft coral of the genus Lobophytum.

Chemical investigation of a soft coral of the genus Lobophytum of the Andaman and Nicobar coasts resulted in the isolation of a new marine sterol acetate, (24S)-ergostane-3beta,5alpha,6beta,25-tetraol-3,6,25-triacetate (1) and of two known sterol glycosides 3beta,4alpha-dihydroxypregn-20-ene-4-O-beta-D-arabinopyranoside and 24-methylenecholest-5-ene-3beta,7beta, 16beta-triol-3-O-alpha-L-fucopyranoside-7beta-acetate. The structures of the compounds were elucidated based on spectral studies and chemical conversions.

Animals↗
PubMed2004

Oceanibulbus indolifex gen. nov., sp. nov., a North Sea alphaproteobacterium that produces bioactive metabolites.

A water sample from the North Sea was used to isolate the abundant heterotrophic bacteria that are able to grow on complex marine media. Isolation was by serial dilution and spread plating. Phylogenetic analysis of nearly complete 16S rRNA gene sequences revealed that one of the strains, HEL-45T, had 97.4% sequence similarity to Sulfitobacter mediterraneus and 96.5 % sequence similarity to Staleya guttiformis. Strain HEL-45T is a Gram-negative, non-motile rod and obligate aerobe and requires sodium and 1-7% sea salts for growth. It contains storage granules and does not produce bacteriochlorophyll. Optimal growth temperatures are 25-30 degrees C. The DNA base composition (G+C content) is 60.1 mol%. Strain HEL-45T has Q10 as the dominant respiratory quinone. The major polar lipids are phosphatidyl glycerol, diphosphatidyl glycerol, phosphatidyl choline, phosphatidyl ethanolamine and an aminolipid. The fatty acids comprise 18 : 1omega7c, 18 : 0, 16 : 1omega7c, 16 : 0, 3-OH 10 : 0, 3-OH 12 : 1 (or 3-oxo 12 : 0) and traces of an 18 : 2 fatty acid. Among the hydroxylated fatty acids only 3-OH 12 : 1 (or 3-oxo 12 : 0) appears to be amide linked, whereas 3-OH 10 : 0 appears to be ester linked. The minor fatty acid components (between 1 and 7%) allow three subgroups to be distinguished in the Sulfitobacter/Staleya clade, placing HEL-45T into a separate lineage characterized by the presence of 3-OH 12 : 1 (or 3-oxo 12 : 0) and both ester- and amide-linked 16 : 1omega7c phospholipids. HEL-45T produces indole and derivatives thereof, several cyclic dipeptides and thryptanthrin. Phylogenetic analysis of 16S rRNA gene sequences and chemotaxonomic data support the description of a new genus and species, to include Oceanibulbus indolifex gen. nov., sp. nov., with the type strain HEL-45T (=DSM 14862T=NCIMB 13983T).

Adaptation, Biological↗
PubMed2004

Chemical constituents of a marine soft coral of the genus Lobophytum.

Chemical investigations on the marine soft coral Lobophytum sp., collected from the Andaman and Nicobar Islands, yielded two new acyl glycerol monoalkyl ethers along with two known compounds of this series (1a-d), and a new ceramide (4a). The structures of the new and known compounds were elucidated on the basis of extensive spectroscopic studies and chemical reactions.

Animals↗
PubMed2004

Helquinoline, a new tetrahydroquinoline antibiotic from Janibacter limosus Hel 1+.

The ethyl acetate extract of cultures of Janibacter limosus showed a high biological activity against bacteria, and fungi and delivered two new natural products, a tetrahydroquinoline derivative designated as helquinoline (1), and the N-acetylkynuramine (3a), along with other known secondary metabolites. The structure of 1 has been elucidated as 4-methoxy-2-methyl-1,2,3,4-tetrahydroquinoline-8-carboxylic acid on the basis of 1D and 2D NMR and mass spectra. The relative stereochemistry of the compound 1 was assigned as 2R*,4R* with the aid of coupling constants, NOESY correlation and by comparison with a related compound.

Actinomycetales↗
PubMed2004

Anti-cancer and antibacterial trioxacarcins with high anti-malaria activity from a marine Streptomycete and their absolute stereochemistry.

The ethyl acetate extract from the Streptomyces sp. isolate B8652 delivered the trioxacarcins A to approximately C (2a to approximately 2c) and additionally three new derivatives designated as trioxacarcins D to approximately F (2d to approximately 2f). All trioxacarcins showed high anti-bacterial and some of them high anti-tumor and anti-malaria activity. The structures of the new antibiotics were derived from mass, 1D and 2D NMR spectra and confirmed by comparison of the NMR data with those of known derivatives. The absolute configuration of the trioxacarcins is deduced from the X-ray analysis of gutingimycin (2g) and from the known stereochemistry of the L-trioxacarcinoses A and B.

Anti-Bacterial Agents↗
PubMed2003

New indole alkaloids from the North Sea bacterium Vibrio parahaemolyticus Bio249.

Several bis- and tris-indole derivatives were isolated from a North Sea bacterium that was closely related to Vibrio parahaemolyticus (98% homology). 1,1,3-Tris(3-indolyl)butane (3) is a new compound, and 3,3-bis(3-indolyl)butane-2-one (1a), arundine (1b), and 1,1,1-tris(3-indolyl)methane (2a) were isolated from a microorganism for the first time here. Additionally, many other known compounds were obtained from the ethyl acetate extract of the culture. Their structures were established on the basis of various spectral data, and their origin is discussed. All compounds were inactive against a range of bacteria and fungi.

Bacillus subtilis↗
PubMed2003

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.

Anthraquinones↗
PubMed2003

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).

Anti-Bacterial Agents↗
PubMed2003

Chandrananimycins A approximately C: production of novel anticancer antibiotics from a marine Actinomadura sp. isolate M048 by variation of medium composition and growth conditions.

In our screening of marine actinomycetes for bioactive principles, three novel antibiotics designated as chandrananimycin A (3c), B (3d) and C (4) were isolated from the culture broth of a marine Actinomadura sp. isolate M045. The structures of the new antibiotics were determined by detailed interpretation of mass, 1D and 2D NMR spectra.

Actinobacteria↗
PubMed2003

Bhimamycin A to approximately E and bhimanone: isolation, structure elucidation and biological activity of novel quinone antibiotics from a terrestrial Streptomycete.

From the ethyl acetate extract of a terrestrial Streptomycete isolate, five new quinone antibiotics, bhimamycin A (2a), B (2b), C (3c), D (5a), E (7) and the new tetralone bhimanone (8) were isolated together with the known microbial products chrysophanol (1a), aloesaponarin II (1b), 3,8-dihydroxy-1-methylanthraquinone-2-carboxylic acid (1c), adenosine, 2'-deoxyadenosine, phenylacetamide, and 2-(p-hydroxyphenyl)ethanol. The structures of these natural products were deduced from the spectral data and confirmed by comparison with related compounds from the literature and by synthesis.

Anti-Bacterial Agents↗
PubMed2003

Himalomycin A and B: isolation and structure elucidation of new fridamycin type antibiotics from a marine Streptomyces isolate.

In our screening of marine Streptomycetes for bioactive compounds, in addition to the known metabolites rabelomycin (1), fridamycin D (2b), N-benzylacetamide and N-(2'-phenylethyl)acetamide, two new anthracycline antibiotics designated as himalomycin A (2c) and B (2d) were isolated from the culture broth of the marine Streptomyces sp. isolate B6921. The structure of the new antibiotics was determined by comparison of the NMR data with those of fridamycin D (2b) and by detailed interpretation of mass, 1D and 2D NMR spectra.

Anthracyclines↗
PubMed2002

Integrated approach to explore the potential of marine microorganisms for the production of bioactive metabolites.

During the last 10 years marine organisms have provided a large number of new natural products. Interesting compounds have mainly been derived from macroorganisms such as sponges, ascidians, corals and bryozoans. The number of secondary metabolites from marine microorganisms is smaller, but rapidly increasing. Because of the enormous difficulties involved in harvesting products from marine animals, and the fact that some of the bioactive compounds are produced by associated bacteria, the advantages of sustainable production of bioactive metabolites by bacteria or fungi, under the protection of natural resources, seem to be very attractive for the future. This review describes current progress in the isolation and identification of novel marine microorganisms, the discovery of new secondary metabolites, the biotechnological approaches to overproduce them, as well as the evaluation and characterization of their bioactivity.

Antineoplastic Agents↗
PubMed2002

Characterization of surfactin-like cyclic depsipeptides synthesized by Bacillus pumilus from ascidian Halocynthia aurantium.

A marine bacterium (KMM 1364), identified as Bacillus pumilus, was isolated from the surface of ascidian Halocynthia aurantium. Structural analysis revealed that the strain KMM 1364 produced a mixture of lipopeptide surfactin analogs with major components with molecular masses of 1035, 1049, 1063, and 1077. The variation in molecular weight represents changes in the number of methylene groups in the lipid and/or peptide portions of the compounds. Structurally, these lipopeptides differ from surfactin in the substitution of the valine residue in position 4 by leucine, and have been isolated as two carboxy-terminal variants, with valine or isoleucine in position 7. As constituents of the lipophilic part of the peptides, only beta-hydroxy-C(15)-, beta-hydroxy-C(16)-, and a high amount of beta-hydroxy-C(17) fatty acid were determined.

Journal Article↗
PubMed2002

Horiolide, a novel norditerpenoid from Indian ocean soft coral of the genus Sinularia.

A novel norditerpenoid, horiolide (1), has been isolated from an Indian Ocean soft coral of the genus Sinularia. The structural elucidation was achieved by a study of its spectral characteristics. This compound is structurally characterized by a new carbon skeleton having one six-membered cyclohexane ring bearing an isopropylene moiety, a carbonyl group, and one seven-membered ring attached to a five-membered lactone moiety.

Animals↗
PubMed2002

Pharacine, a natural p-cyclophane and other indole derivatives from Cytophaga sp. strain AM13.1.

From the ethyl acetate extract of the bacterial strain Cytophaga sp. AM13.1, among many known compounds, the new natural products 2,5-bis(3-indolylmethyl)pyrazine (2) and a highly symmetrical p-cyclophane named pharacine (5) were identified. In addition, tryptamine isovalerate (1) and p-hydroxyphenylacetamide (4), known as plant metabolites, were isolated and characterized from a microorganism for the first time. The new natural products showed no activity against three microalgae, the fungus Mucor miehei, the yeast Candida albicans, and the bacteria Staphylococcus aureus, Bacillussubtilis, Escherichia coli, and Streptomyces viridochromogenes.

Bacillus subtilis↗
PubMed2002

Limnazine, the first bacterial azine derivative from Bacillus sp. GW90a.

A novel dimeric azine derivative designated as limnazine (1) has been isolated from the culture broth of an aquatic Bacillus sp. strain GW90a. The structure has been elucidated, on the basis of spectral data, as N,N'-bis(2,2,6-trimethylchroman-4-ylidene)azine and was additionally confirmed by synthesis. Limnazine (1) is inactive against algae, fungi, and bacteria.

Bacillus↗