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.

/pdf/single-crystal-structure-validation-with-the-program-platon-2pdiuo25f2.pdf

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.

The dendronotid nudibranch Tritonia hamnerorurn was observed on some reefs In the Flonda Keys, USA, at very high densities dunng the summer of 1992 T hamnerorum specializes on the sea fan Gorgonia vental~na and sequesters the furano-germacrene lulieannafuran from its host, this compound effectively protects the nudibranch from consumption by the common predatoiy reef f ~ s h Thalassoma bifasciatum T hamnerorum densit~es were extremely hlgh at some locations, with as Inany as 1700 nudibranchs found on a single G ventalina colony At high densities, nudibranch feeding killed large areas on some sea fan colonies by stnpping all tissue from portions of the sea fan and allowing fllamentous algae and other epibionts to colonize The density of T hamnerorum on G ventahna vaned greatly on scales of centimeters meters and k~lometers High density patches of nudlbranchs on individual sea fans were usually composed of equivalent-sized nudtbranchs These observations suggest that pelagic vellgers have an incredible capabil~ty to find and settle synchronously on one portion of a sea fan or that the larvae or luveniles hatch from egg masses and develop without leaving the sea fan This study adds to a growlng number of manne examples suggesting that feeding specialization occurs pnmardy among small sedentary consumers that deter or escape predators by associating w t h defended hosts

/pdf/distribution-density-and-sequestration-of-host-chemical-mo15pxu7fx.pdf

Distribution, density, and sequestration of host chemical defenses by the specialist nudibranch Tritonia hamnerorum found at high densities on the sea fan Gorgonia ventalina

William Fenical

Papers

Distribution, density, and sequestration of host chemical defenses by the specialist nudibranch Tritonia hamnerorum found at high densities on the sea fan Gorgonia ventalina

Pharmaceuticals from marine natural products: surge or ebb?

N-Methylsansalvamide, a cytotoxic cyclic depsipeptide from a marine fungus of the genus Fusarium

Isolation of the muricins : Evidence of a chemical adaptation against fouling in the marine octocoral Muricea fruticosa (gorgonacea)

Two antifeedant lignans from the freshwater macrophyte Saururus cernuus.