Minimum Information about a Biosynthetic Gene cluster

A wide variety of enzymatic pathways that produce specialized metabolites in bacteria, fungi and plants are known to be encoded in biosynthetic gene clusters. Information about these clusters, pathways and metabolites is currently dispersed throughout the literature, making it difficult to exploit. To facilitate consistent and systematic deposition and retrieval of data on biosynthetic gene clusters, we propose the Minimum Information about a Biosynthetic Gene cluster (MIBiG) data standard.Chemistry and Chemical Biolog

Evaluation of Biosynthetic Pathway and Engineered Biosynthesis of Alkaloids

Varieties of alkaloids are known to be produced by various organisms, including bacteria, fungi and plants, as secondary metabolites that exhibit useful bioactivities. However, understanding of how those metabolites are biosynthesized still remains limited, because most of these compounds are isolated from plants and at a trace level of production. In this review, we focus on recent efforts in identifying the genes responsible for the biosynthesis of those nitrogen-containing natural products and elucidating the mechanisms involved in the biosynthetic processes. The alkaloids discussed in this review are ditryptophenaline (dimeric diketopiperazine alkaloid), saframycin (tetrahydroisoquinoline alkaloid), strictosidine (monoterpene indole alkaloid), ergotamine (ergot alkaloid) and opiates (benzylisoquinoline and morphinan alkaloid). This review also discusses the engineered biosynthesis of these compounds, primarily through heterologous reconstitution of target biosynthetic pathways in suitable hosts, such as Escherichia coli, Saccharomyces cerevisiae and Aspergillus nidulans. Those heterologous biosynthetic systems can be used to confirm the functions of the isolated genes, economically scale up the production of the alkaloids for commercial distributions and engineer the biosynthetic pathways to produce valuable analogs of the alkaloids. In particular, extensive involvement of oxidation reactions catalyzed by oxidoreductases, such as cytochrome P450s, during the secondary metabolite biosynthesis is discussed in details

Texture Transfer Based on Energy Minimization for Painterly Rendering

Non-photorealistic rendering (NPR) creates images with artistic styles of paintings. In this field, a number of methods of converting photographed images into non-photorealistic ones have been developed, and can be categorized into filter-based and exemplar-based approaches. In this paper, we focus on the exemplar-based approach and propose a novel method which transfers a style of a reference pictorial image to a photographed image. Specifically, we first input a pair of target and reference images. The target image is converted by minimizing an energy function which is defined based on the difference in intensities between an output image and a target image, and the pattern dissimilarity between an output image and a reference image. The proposed method transfers structures and colors of textures in the reference image and generates continuous textures by minimizing the energy function. In experiments, we demonstrate the effectiveness of the proposed method using a variety of images and examine the influence of parameter changes and intensity adjustment for pre-processing on resultant images

Elucidation of Pyranonigrin Biosynthetic Pathway Reveals a Mode of Tetramic Acid, Fused γ‑Pyrone, and <i>exo</i>-Methylene Formation

Successful activation of the pyranonigrin biosynthetic gene cluster and gene knockout in <i>Aspergillus niger</i> plus in vivo and in vitro assays led to isolation of six new products, including a spiro cyclobutane-containing dimeric compound, which served as the basis for the proposed comprehensive pyranonigrin biosynthetic pathway. Two redox enzymes are key to forming the characteristic fused γ-pyrone core, and a protease homologue performs the <i>exo</i>-methylene formation

Structure and Biological Activity of 8‑Deoxyheronamide C from a Marine-Derived <i>Streptomyces</i> sp.: Heronamides Target Saturated Hydrocarbon Chains in Lipid Membranes

Polyene macrolactams are a class of microbial metabolites, many of which show potent biological activities with unidentified modes of action. Here we report that 8-deoxyheronamide C, a new 20-membered polyene macrolactam from a marine-derived actinomycete <i>Streptomyces</i> sp., is a unique membrane binder. 8-Deoxyheronamide C showed a characteristic sensitivity profile against fission yeast sterol mutant cells, indicating that the metabolite targets cell membranes. We detected tight physical interaction between heronamides including 8-deoxyheronamide C and heronamide C and saturated hydrocarbon chains in lipid membranes using surface plasmon resonance experiments. We further show that heronamides induced abnormal cell wall morphology in fission yeast probably by perturbing the structure of membrane microdomains. This work will accelerate the biological and medical investigation of polyene macrolactams

Structure and Biological Activity of 8‑Deoxyheronamide C from a Marine-Derived <i>Streptomyces</i> sp.: Heronamides Target Saturated Hydrocarbon Chains in Lipid Membranes

Polyene macrolactams are a class of microbial metabolites, many of which show potent biological activities with unidentified modes of action. Here we report that 8-deoxyheronamide C, a new 20-membered polyene macrolactam from a marine-derived actinomycete <i>Streptomyces</i> sp., is a unique membrane binder. 8-Deoxyheronamide C showed a characteristic sensitivity profile against fission yeast sterol mutant cells, indicating that the metabolite targets cell membranes. We detected tight physical interaction between heronamides including 8-deoxyheronamide C and heronamide C and saturated hydrocarbon chains in lipid membranes using surface plasmon resonance experiments. We further show that heronamides induced abnormal cell wall morphology in fission yeast probably by perturbing the structure of membrane microdomains. This work will accelerate the biological and medical investigation of polyene macrolactams

Isolation, Structure Elucidation, and Total Synthesis of Tryptopeptins A and B, New TGF‑β Signaling Modulators from <i>Streptomyces</i> sp.

Two new microbial metabolites, tryptopeptins A (<b>1</b>) and B (<b>2</b>), were isolated from the cultured broth of <i>Streptomyces</i> sp. KUSC-G11, as modulators of the transforming growth factor-β (TGF-β) signaling pathway. Their chemical structures consisting of isovalerate, <i>N</i>-Me-l-Val, l-<i>allo</i>-Thr, and a tryptophan-related residue were elucidated on the basis of spectroscopic analyses, while they were unambiguously determined by total syntheses. A structure–activity relationship (SAR) study using natural and synthesized tryptopeptins revealed the importance of the α,β-epoxyketone function located at the <i>C</i> terminus. These new TGF-β signaling modulators would be highly useful for development of new drug leads targeting TGF-β-related diseases such as fibrosis and cancer