The occurrence of secondary metabolism is a feature common to all living organisms, but restricted to certain taxa. Intermediary metabolism and its products are reasonably well known, but our knowledge of secondary pathways and metabolites is still very limited. Starting from given precursors from intermediary metabolism, in secondary metabolism the evolution of biochemical pathways can proceed in all directions provided that the metabolites are toxic to the producing organism, at least not at the time of their appearance. The main selection principle during the evolution of organisms which can afford the luxury of a biochemical playground cannot be fast growth and short generation times. A continuous evolution of biochemical pathways in secondary metabolism must occasionally lead to compounds which offer an advantage to the producing organism. The playground of secondary metabolism is probably a very early relic of biochemical evolution.

From the gastrointestinal tract of a fish dredged near the South Orkney Islands in Antarctica, we isolated the psychrotolerant bacterial strain T262, which belongs to the species Vibrio splendidus. Investigation of this strain led to the isolation of a series of 15 bis- and trisindole derivatives. Among them, six new indole alkaloids, namely, turbomycin C [4'-n-butoxyphenyl-bis (1H-indol-3-yl)methane, 1a], turbomycin D [4'-n-propoxyphenyl-bis(1H-indol-3-yl) methane, 1b], turbomycin E [4'-ethoxyphenyl-bis(1H-indol-3-yl) methane, 1c], turbomycin F [4'-methoxy-3', 5'-dinitrophenyl-bis(1H-indol-3-yl) methane, 2], trisindolal (3a), and 4-(1H-indol-3-yl-sulfanyl)phenol (4). Another new bisindole derivative elucidated as 2-(indol-3-ylmethyl)-indol-3-ylethanol (7a) was obtained together with six known compounds from the psychrotolerant Arthrobacter psychrochitiniphilus strain T406, isolated from the excrement of penguins. Some of the isolated compounds showed activity against both gram-positive and gram-negative bacteria at 10 mu g/paper disk. Trisindolal (3a) was active against the peronosporomycetes Botrytis cinerea and Phytophthora infestans, and some of the indole derivatives indicated promising cytotoxicity towards human tumor cell lines. By exhibiting a mean IC50 of 0.45 mu g/mL (1.17 mu M), trisindolal (3a) showed pronounced potency and selectivity in a panel of 11 human tumor cell lines derived from 10 different tumor histotypes.

In a screening for inhibitors of infection-related morphogenesis in the rice blast fungus Magnaporthe oryzae, a series of 10 coumarin derivatives were isolated from Pedilanthus tithymaloides (Euphorbiaceae). Seven of these compounds turned out to be known while three represent previously unreported natural products. Their structures were established on the basis of spectroscopic data and X-ray crystallography. Nine out of 10 coumarin derivatives were found to inhibit conidial germination in the phytopathogenic fungus at low concentrations.

From the basidiomycete Marasmius sp., strain IBWF 96046, three new sesquiterpenoids based on the drimane skeleton were isolated and named marasmene B and marasmals B and C. In this study, their isolation, structure elucidation, and biological evaluation are described. The compounds have a pronounced inhibitory effect on the conidial germination of several plant-pathogenic fungi.

GKK1032A 2 , a secondary metabolite from Penicillium sp. IBWF-029-96, inhibits conidial germination in the rice blast fungus Magnaporthe oryzae

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

The structures of secondary metabolites with antibacterial and cytotoxic activities produced by a marine Vibrio strain from the Red Sea were elucidated. Aqabamycin A (1a) and seven further nitro-substituted maleimide derivates named aqabamycins B–G (1b–f and 2) were obtained together with 12 known metabolites, 3-nitro-1H-indazole (3), indazole-3-carbaldehyde (4), 3-nitro-4-hydroxycinnamic acid, 4-hydroxycinnamic acid, 3-nitro-4-hydroxybenzaldehyde, phenyl-2-bis-indolylmethane (5a), turbomycin B (5b), vibrindole A (6), phenylacetic acid, 3-hydroxybenzoic acid, benzoic acid and 1,4-dithiane (7). Some of the known metabolites (for example, 3, 4 and 7) are described in this study for the first time as natural products. Their structures were elucidated based on 1D and 2D NMR, MS spectra and by comparison with synthetic material.

In a screening of marine bacteria, a Vibrio species isolated from the surface of the soft coral Sinularia polydactyla collected in the Red Sea was found to be a prolific producer of secondary metabolites with antibacterial and cytotoxic activities. Seven novel maleimide derivatives named aqabamycin A ( 1a ), aqabamycin B (1b ), aqabamycin C ( 1c ), aqabamycin D ( 1d ), aqabamycin E ( 1e and 1e′ ), aqabamycin F ( 1f ) and aqabamycin G ( 2 ) were isolated together with several known metabolites such as 3-nitro-1 H -indazole ( 3 ), indazole-3-carbaldehyde ( 4 ), phenyl-2-bis-indolylmethane ( 5a ), turbomycin B ( 5b ), vibrindole A ( 6 ), 1,4-dithiane ( 7 ), 3-(3-nitro-4-hydroxyphenyl)-2-propenoic acid ( 8 ), 3-nitro-4-hydroxybenzaldehyde ( 9 ), phenylacetic acid, benzoic acid, 3-hydroxybenzoic acid and 4-hydroxycinnamic acid. The aqabamycins, except aqabamycin A, bear a nitro group. Compounds 3 , 4 , 7 are described here for the first time from a natural source and vibrindole A was found to have cytotoxic activity.

ChemInformVolume 41, Issue 42 Natural Products ChemInform Abstract: Marine Bacteria. Part 42. Aqabamycins A-G: Novel Nitro Maleimides from a Marine Vibrio Species. Part 2. Structure Elucidation. Clarisse Blandine Fotso Fondja Yao, Inst. Org. Biomol. Chem., Georg-August-Univ., D-37077 Goettingen, GermanySearch for more papers by this authorWael Al Zereini, Inst. Org. Biomol. Chem., Georg-August-Univ., D-37077 Goettingen, GermanySearch for more papers by this authorSerge Fotso, Inst. Org. Biomol. Chem., Georg-August-Univ., D-37077 Goettingen, GermanySearch for more papers by this authorHeidrun Anke, Inst. Org. Biomol. Chem., Georg-August-Univ., D-37077 Goettingen, GermanySearch for more papers by this authorHartmut Laatsch, Inst. Org. Biomol. Chem., Georg-August-Univ., D-37077 Goettingen, GermanySearch for more papers by this author Clarisse Blandine Fotso Fondja Yao, Inst. Org. Biomol. Chem., Georg-August-Univ., D-37077 Goettingen, GermanySearch for more papers by this authorWael Al Zereini, Inst. Org. Biomol. Chem., Georg-August-Univ., D-37077 Goettingen, GermanySearch for more papers by this authorSerge Fotso, Inst. Org. Biomol. Chem., Georg-August-Univ., D-37077 Goettingen, GermanySearch for more papers by this authorHeidrun Anke, Inst. Org. Biomol. Chem., Georg-August-Univ., D-37077 Goettingen, GermanySearch for more papers by this authorHartmut Laatsch, Inst. Org. Biomol. Chem., Georg-August-Univ., D-37077 Goettingen, GermanySearch for more papers by this author First published: 23 September 2010 https://doi.org/10.1002/chin.201042218AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume41, Issue42October 19, 2010 RelatedInformation

Caripyrin (trans-5-(3-methyloxiranyl)pyridincarboxylic acid methyl ester, 1), a new pyridyloxirane, was isolated from submerged cultures of the basidiomycete Caripia montagnei. The compound was found to inhibit conidial germination and appressorium formation in the rice blast fungus Magnaporthe oryzae, whereas the infection-related morphogenesis in several other phytopathogenic fungi was not affected. In plant assays on rice, 1 was found to protect plants more efficiently against fungal infection than the structurally related fungal secondary metabolite, fusaric acid. Contrary to the latter, 1 was neither cytotoxic, antibacterial, nor nematicidal.

The new pyridyloxirane caripyrin (I) is isolated from submerged cultures of the basidiomycete Caripia montagnei.

Seven novel maleimide derivatives are isolated from the surface of the soft coral Sinularia polydactyla collected from the Red Sea.

The adverse effects on human health and well being and the high economic losses inflicted by pathogenic nematodes are important stimulants for the search of new, safe and effective nematicides and anthelminthics. The pool of natural products is an important source for such compounds, and several of the most potent nematicides used today originate from streptomycetes. Higher fungi have an extensive secondary metabolism at their disposal, and obviously some benefit from the capability to kill nematodes. Surprisingly little is known about the production of nematicidal metabolites by fungi. Examples of compounds isolated from ascomycetes are the cochlioquinones and the mycorrhizins, which are strongly active against the saprophytic Caenorhabditis elegans but not towards the economically important plant pathogen Meloidogyne incognita. From basidiomycetes, the cyclic dodecapeptide omphalotin was obtained which seems to be highly selective for M. incognita. Compounds with good activity against a abomasum nematode in vivo are the macrodiolides clonostachydiol and helminidiol. When screening for nematicidal activity, it is important to use the proper test system as the sensitivity of different nematodes may vary considerably. Consequently, the search for agents active against M. incognita may be futile, if saprophytic nematodes are used as test organisms. The importance to develop relevant screening systems that are easy to use and have an acceptable capacity is therefore emphasized.

The structures of secondary metabolites with antibacterial and cytotoxic activities produced by a marine Vibrio strain from the Red Sea were elucidated. Aqabamycin A (1a) and seven further nitro-substituted maleimide derivates named aqabamycins B–G (1b–f and 2) were obtained together with 12 known metabolites, 3-nitro-1H-indazole (3), indazole-3-carbaldehyde (4), 3-nitro-4-hydroxycinnamic acid, 4-hydroxycinnamic acid, 3-nitro-4-hydroxybenzaldehyde, phenyl-2-bis-indolylmethane (5a), turbomycin B (5b), vibrindole A (6), phenylacetic acid, 3-hydroxybenzoic acid, benzoic acid and 1,4-dithiane (7). Some of the known metabolites (for example, 3, 4 and 7) are described in this study for the first time as natural products. Their structures were elucidated based on 1D and 2D NMR, MS spectra and by comparison with synthetic material.

The nonenolide hypocreolide A was isolated from culture filtrates of the ascomycete Hypocrea lactea. It exhibits moderate antimicrobial activity against various tested fungi and bacteria. Since neither the relative nor the absolute stereochemistry of the compound could be initially assigned, a stereochemically flexible total synthesis was developed. The two stereogenic centers were formed in high enantioselectivity and yield using transition metal catalyzed asymmetric reactions. While attempts to construct the ten-membered lactone in a ring-closing olefin metathesis gave disappointing results, a combination of cross metathesis and macrolactonization provided the title compound in nine steps and 12% overall yield.

Fatty acids are essential components of almost all biological membranes. Additionally, they are important in energy storage, as second messengers during signal transduction, and in post-translational protein modification. De novo synthesis of fatty acids is essential for almost all organisms, and entails the iterative elongation of the growing fatty acid chain through a set of reactions conserved in all kingdoms. During our work on the biosynthesis of secondary metabolites, a 450-kDa protein was detected by SDS-PAGE of enriched fractions from mycelial lysates from the basidiomycete Omphalotus olearius. Protein sequencing of this protein band revealed the presence of peptides with homology to both α and β subunits of the ascomycete fatty acid synthase (FAS) family. The FAS encoding gene of O. olearius was sequenced. The positions of its predicted 21 introns were verified. The gene encodes a 3931 amino acids single protein, with an equivalent of the ascomycetous β subunit at the N-terminus and the α subunit at the C-terminus. This is the first report on an FAS protein from a homobasidiomycete and also the first fungal FAS which is comprised of a single polypeptide.

The isolation, biological characterization, and structure elucidation of xanthepinone, a novel antifungal metabolite isolated from the broth of submerged cultures of a soil fungus, are described. Xanthepinone inhibits the conidial germination of Magnaporthe grisea (2 microg/mL), Phytophthora infestans (5 microg/mL), and Botrytis cinerea (10 microg/mL) while showing only weak antibacterial activity; cytotoxicity was not observed up to 50 microg/mL. Molecular taxonomy revealed that the producing strain is close to species in the genus Phoma as well as to uncultured soil fungi and endophytes.

Four members of a new family of tetracyclic sesquiterenoids possessing the isolactarane skeleton have been isolated from mycelial cultures of Stereum sp. IBWF 01060. Their structure elucidation and their antifungal activity against several plant pathogens as well as other microorganisms are reported.