Patulin is a toxic chemical contaminant produced by several species of mold, especially within Aspergillus, Penicillium and Byssochlamys. It is the most common mycotoxin found in apples and apple-derived products such as juice, cider, compotes and other food intended for young children. Exposure to this mycotoxin is associated with immunological, neurological and gastrointestinal outcomes. Assessment of the health risks due to patulin consumption by humans has led many countries to regulate the quantity in food. A full understanding of the molecular genetics of patulin biosynthesis is incomplete, unlike other regulated mycotoxins (aflatoxins, trichothecenes and fumonisins), although the chemical structures of patulin precursors are now known. The biosynthetic pathway consists of approximately 10 steps, as suggested by biochemical studies. Recently, a cluster of 15 genes involved in patulin biosynthesis was reported, containing characterized enzymes, a regulation factor and transporter genes. This review includes information on the current understanding of the mechanisms of patulin toxinogenesis and summarizes its toxicological effects.

Biosynthesis and toxicological effects of patulin.

The type I fatty acid and polyketide synthases: a tale of two megasynthases.

Deep Sea Adriana Lorente,†,‡ Janire Lamariano-Merketegi,†,‡ Fernando Albericio,†,‡,§,# and Mercedes Álvarez*,†,‡,⊥ †Institute for Research in Biomedicine, Barcelona Science Park, University of Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain ‡CIBER-BBN, Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Barcelona Science Park, Baldiri Reixac 10, 08028 Barcelona, Spain Department of Organic Chemistry, University of Barcelona, 08028 Barcelona, Spain School of Chemistry, University of KwaZulu-Natal, 4001-Durban, South Africa Laboratory of Organic Chemistry, Faculty of Pharmacy, University of Barcelona, 08028 Barcelona, Spain

Tetrahydrofuran-containing macrolides: a fascinating gift from the deep sea.

The biotin-dependent enzymes.

Fungal aromatic polyketides constitute a large family of bioactive natural products and are synthesized by the non-reducing group of iterative polyketide synthases (PKSs). Their diverse structures arise from selective enzymatic modifications of reactive, enzyme-bound poly-β-keto intermediates. How iterative PKSs control starter unit selection, polyketide chain initiation and elongation, intermediate folding and cyclization, selective redox or modification reactions during assembly, and product release are central mechanistic questions underlying iterative catalysis. This Review highlights recent insights into these questions, with a particular focus on the biosynthetic programming of fungal aromatic polyketides, and draws comparisons with the allied biosynthetic processes in bacteria.

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New insights into the formation of fungal aromatic polyketides

The general problem of the biosynthesis of depsides and depsidones is considered. Feeding experiments using sodium acetate isotopically labelled in the carboxyl group have demonstrated that the mould Penicillium griseofulvum Dierckx (Raistrick's strain P68) elaborates 2-hydroxy-6-methylbenzoic acid (VII) by the head-to-tail linkage of acetic acid units in accord with the hypothesis of Birch and Donovan (1953). This demonstration constitutes the first definite support for the hypothesis based on bio- chemical experiments.

RA Massy-Westropp

Papers

Studies in relation to biosynthesis. VII. 2-Hydroxy-6-methylbenzoic acid in Penicillium griseofulvum Dierckx