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Two new metabolites, diorcinolic acid (1) and β-d-glucopyranosyl aspergillusene A (8), together with six diphenylethers (2–7), a diketopiperazine (9), a chromone (10) and a xanthone (11) were isolated from the fungus Aspergillus sydowii derived from the marine sponge Stelletta sp. The planar structures and their relative configurations were elucidated by analysing 1D, 2D NMR and HRESIMS data. Compound 8 is the first glycoside of phenolic bisabolane sesquiterpenes. Compounds 1 and 8 exhibited mild cytotoxicity against KB (human nasopharyngeal carcinoma cells), HepG2 (human liver cancer cells) and HCT 116 (human colon cancer cells). All compounds were evaluated for antibacterial activity and their abilities to suppress LPS-induced nitric oxide (NO) production. Compounds 2 and 4–7 showed mild antibacterial activity against human pathogen Staphylococcus aureus and fish pathogens Streptococcus iniae and Vibrio ichthyoenteri, and compounds 4 and 7 weakly suppressed NO production. [ABSTRACT FROM AUTHOR]

Discovered 40 years ago, plant glutathione transferases (GSTs) now have a well-established role in determining herbicide metabolism and selectivity in crops and weeds. Within the GST superfamily, the numerous and plant-specific phi (F) and tau (U) classes are largely responsible for catalyzing glutathione-dependent reactions with xenobiotics, notably conjugation leading to detoxification and, more rarely, bioactivating isomerizations. In total, the crystal structures of 10 plant GSTs have been solved and a highly conserved N-terminal glutathione binding domain and structurally diverse C-terminal hydrophobic domain identified, along with key coordinating residues. Unlike drug-detoxifying mammalian GSTs, plant enzymes utlilize a catalytic serine in place of a tyrosine residue. Both GSTFs and GSTUs undergo changes in structure during catalysis indicative of an induced fit mechanism on substrate binding, with an understanding of plant GST structure/function allowing these proteins to be engineered for novel functions in detoxification and ligand recognition. Several major crops produce alternative thiols, with GSTUs shown to use homoglutathione in preference to glutathione, in herbicide detoxification reactions in soybeans. Similarly, hydroxymethylglutathione is used, in addition to glutathione in detoxifying the herbicide fenoxaprop in wheat. Following GST action, plants are able to rapidly process glutathione conjugates by at least two distinct pathways, with the available evidence suggesting these function in an organ- and species-specific manner. Roles for GSTs in endogenous metabolism are less well defined, with the enzymes linked to a diverse range of functions, including signaling, counteracting oxidative stress, and detoxifying and transporting secondary metabolites. [ABSTRACT FROM AUTHOR]

The fungus, Tritirachium sp. HKI 0317, was isolated from the Antarctic lichen Neuropogon sp. Fermentation of this strain, extraction of the culture broth, and preparative separation of produced compounds furnished 4‐carboxy‐5,5′‐dihydroxy‐3,3′‐dimethyldiphenylether (1), macrosphelide A (2), and macrosphelide J (3). The structures were elucidated on the basis of MS and NMR measurements, and the previously published data for this compounds. [ABSTRACT FROM AUTHOR]