The results of a single-crystal structure determination when in CIF format can now be validated routinely by automatic procedures. In this way, many errors in published papers can be avoided. The validation software generates a set of ALERTS detailing issues to be addressed by the experimenter, author, referee and publication journal. Validation was pioneered by the IUCr journal Acta Crystallographica Section C and is currently standard procedure for structures submitted for publication in all IUCr journals. The implementation of validation procedures by other journals is in progress. This paper describes the concepts of validation and the classes of checks that are carried out by the program PLATON as part of the IUCr checkCIF facility. PLATON validation can be run at any stage of the structure refinement, independent of the structure determination package used, and is recommended for use as a routine tool during or at least at the completion of every structure determination. Two examples are discussed where proper validation procedures could have avoided the publication of incorrect structures that had serious consequences for the chemistry involved.

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Single-crystal structure validation with the program PLATON

Chemistry and biochemistry of 4-hydroxynonenal, malonaldehyde and related aldehydes.

https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Physiological and ecological constraints play key roles in the evolution of plant growth patterns, especially in relation to defenses against herbivores. Phenotypic and life history theories are unified within the growth-differentiation balance (GDB) framework, forming an integrated system of theories explaining and predicting patterns of plant defense and competitive interactions in ecological and evolutionary time. Plant activity at the cellular level can be classified as growth (cell division and enlargement) of differentiation (chemical and morphological changes leading to cell maturation and specialization). The GDB hypothesis of plant defense is premised upon a physiological trade-off between growth and differentiation processes. The trade-off between growth and defense exists because secondary metabolism and structural reinforcement are physiologically constrained in dividing and enlarging cells, and because they divert resources from the production of new leaf area. Hence the dilemma of plants: Th...

https://www.jstor.org/stable/pdfplus/2830650.pdf

The dilemma of plants: To grow or defend.

Advances in flavonoid research since 1992.

Salinamide F, new depsipeptide antibiotic and inhibitor of bacterial RNA polymerase from a marine-derived Streptomyces sp.

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Recent fermentation studies have identified actinomycetes of the marine-dwelling genus Salinispora as prolific natural product producers. To further evaluate their biosynthetic potential, we analyzed all identifiable secondary natural product gene clusters from the recently sequenced 5,184,724 bp S. tropica CNB-440 circular genome. Our analysis shows that biosynthetic potential meets or exceeds that shown by previous Streptomyces genome sequences as well as other natural product-producing actinomycetes. The S. tropica genome features nine polyketide synthase systems of every known formally classified family, non-ribosomal peptide synthetases and several hybrid clusters. While a few clusters appear to encode molecules previously identified in Streptomyces species, the majority of the 15 biosynthetic loci are novel. Specific chemical information about putative and observed natural product molecules is presented and discussed. In addition, our bioinformatic analysis was critical for the structure elucidation of the novel polyenemacrolactam salinilactam A. This study demonstrates the potential for genomic analysis to complement and strengthen traditional natural product isolation studies and firmly establishes the genus Salinispora as a rich source of novel drug-like molecules.

Genome sequencing reveals complex secondary metabolome in the marine actinomycete Salinispora tropica

Cytokines produced through the Antigen Presenting Cell (APC)–T-cell interaction play a key role in the activation of the allergic asthmatic response. Evaluating small molecules that inhibit the production of these pro-inflammatory proteins is therefore important for the discovery of novel chemical structures with potential anti-asthma activity. We adapted a mouse splenocyte cytokine assay to screen a library of 2,500 marine microbial extracts for their ability to inhibit TH2 cytokine release and identified potent activity in a marine-derived strain CNQ431, identified as a Streptomyces species. Bioactivity guided fractionation of the organic extract of this strain led to the isolation of ten new 9-membered bis-lactones, splenocins A-J (1–10). The new compounds display potent biological activities, comparable to that of the corticosteroid dexamethasone, with IC50 values from 2–50 nanomolar in the splenocyte cytokine assay. This study provides the foundation for the optimization of these potent anti-inflammatory compounds for development in the treatment of asthma.

Potent Inhibitors of Pro-Inflammatory Cytokine Production Produced by a Marine-Derived Bacterium

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William Fenical

Papers

Salinamide F, new depsipeptide antibiotic and inhibitor of bacterial RNA polymerase from a marine-derived Streptomyces sp.

Genome sequencing reveals complex secondary metabolome in the marine actinomycete Salinispora tropica

Potent Inhibitors of Pro-Inflammatory Cytokine Production Produced by a Marine-Derived Bacterium

Marine Biodiversity and the Medicine Cabinet: The Status of New Drugs from Marine Organisms

Chemical variation in a new bromochamigrene derivative from the red seaweed Laurencia pacifica