Expanding the occurrence of antimalarial metabolites in dorid nudibranch Hypselodoris tryoni.

This study examined the antimalarial activity of a furanosesquiterpene, furodysinin, one of the major metabolites of the dorid nudibranch Hypselodoris tryoni. The nudibranchs were collected from Balinese waters and the metabolites were purified by chromatography. Ex vivo rodent malaria Plasmodium berghei assays were conducted to determine the metabolite antimalarial activity.

Litosetoenins A-E, Diterpenoids from the Soft Coral , Backbone-Rearranged through Divergent Cyclization Achieved by Epoxide Reactivity Inversion.

Litosetoenins A-E (-), five new ring-rearranged serrulatane-type diterpenoids with a common tricyclo[3.0.4]decane core, along with a known diterpenoid glycoside (), a related known diterpenoid (), and four known sesquiterpenoids (-), were isolated from a Balinese soft coral .

Sinulasterols A-C, three new bioactive oxygenated steroids from the South China Sea soft coral Sinularia depressa.

Three new oxygenated steroids, sinulasterols A-C (1-3), along with seven known related steroids 4-10, were isolated from the Chinese soft coral Sinularia depressa. The structures of the new compounds were established from extensive spectroscopic data analyses and by comparison of their spectral data with those reported in the literature. Among the new compounds, metabolites 1 and 2 featured on unusual C-18 oxygenated pattern.

Bioactivity of compounds secreted by symbiont bacteria of Nudibranchs from Indonesia.

The aims of this work are to isolate bacterial symbionts from nudibranchs and subsequently to determine anti-Methicillin resistant (MRSA), cytotoxicity and anti-Herpes simplex virus type 1 (HSV-1) activities of bio compounds. A total of 15 species of nudibranchs were collected from Karimunjawa and five species from Bali, respectively. A total of 245 bacteria isolates were obtained.

Amphilectene Diterpene Isonitriles and Formamido Derivatives from the Hainan Nudibranch .

Terpene content of two distinct collections of the nudibranch from the South China Sea has been chemically analyzed. A series of amphilectene diterpenes, most likely of dietary origin, with isocyano and formamido functionalities have been isolated from both collections and spectroscopically characterized by an exhaustive nuclear magnetic resonance (NMR) analysis. Interestingly, the structural architecture of compounds - and with both 8,13- and 12,13- ring junctions is unprecedented in the amphilectene skeleton.

Distribution of Defensive Metabolites in Nudibranch Molluscs.

Many plants and animals store toxic or unpalatable compounds in tissues that are easily encountered by predators during attack. Defensive compounds can be produced de novo, or obtained from dietary sources and stored directly without selection or modification, or can be selectively sequestered or biotransformed. Storage strategies should be optimized to produce effective defence mechanisms but also prevent autotoxicity of the host.

Corrigenda: Polyphyly of the traditional family Flabellinidae affects a major group of Nudibranchia: aeolidacean taxonomic reassessment with descriptions of several new families, genera, and species (Mollusca, Gastropoda). https://doi.org/10.3897/zookeys.717.21885.

[This corrects the article DOI: 10.3897/zookeys.717.

Polyphyly of the traditional family Flabellinidae affects a major group of Nudibranchia: aeolidacean taxonomic reassessment with descriptions of several new families, genera, and species (Mollusca, Gastropoda).

The Flabellinidae, a heterogeneous assembly of supposedly plesiomorphic to very derived sea slug groups, have not yet been addressed by integrative studies. Here novel material of rarely seen Arctic taxa as well as North Atlantic, North and South Pacific, and tropical Indo-West Pacific flabellinid species is investigated morpho-anatomically and with multi-locus markers (partial COI, 16S rDNA, 28S rDNA and H3) which were generated and analysed in a comprehensive aeolid taxon sampling. It was found that the current family Flabellinidae is polyphyletic and its phylogeny and taxonomic patterns cannot be understood without considering members from all the Aeolidacean families and, based on a robust phylogenetic hypothesis, morpho-anatomical evolution of aeolids is more complex than suspected in earlier works and requires reclassification of the taxon.

Volatile secondary metabolites as aposematic olfactory signals and defensive weapons in aquatic environments.

Olfaction is considered a distance sense; hence, aquatic olfaction is thought to be mediated only by molecules dissolved in water. Here, we challenge this view by showing that shrimp and fish can recognize the presence of hydrophobic olfactory cues by a "tactile" form of chemoreception. We found that odiferous furanosesquiterpenes protect both the Mediterranean octocoral and its specialist predator, the nudibranch gastropod , from potential predators.

Choose Your Weaponry: Selective Storage of a Single Toxic Compound, Latrunculin A, by Closely Related Nudibranch Molluscs.

Natural products play an invaluable role as a starting point in the drug discovery process, and plants and animals use many interesting biologically active natural products as a chemical defense mechanism against predators. Among marine organisms, many nudibranch gastropods are known to derive defensive metabolites from the sponges they eat. Here we investigated the putative sequestration of the toxic compound latrunculin A--a 16-membered macrolide that prevents actin polymerization within cellular processes--which has been identified from sponge sources, by five closely related nudibranch molluscs of the genus Chromodoris.

Absolute Configuration and Conformational Study of Psammaplysins A and B from the Balinese Marine Sponge Aplysinella strongylata.

The absolute configuration of psammaplysin A (1) has been assigned as (6R,7R) using experimental and calculated electronic circular dichroism (ECD) data and NMR analysis of MPA esters prepared from the acetamide derivative of 1. Detailed conformational analyses of a truncated model compound of 1 with an in vacuo method and with the PCM solvent model for MeOH have identified the major conformers and factors governing the ECD spectrum of 1. The correlation of the ECD data with the stereochemistry of 1 allows configurational assignment of related psammaplysin analogues on the basis of their ECD spectra.

Oxygenated Terpenes from Indo-Pacific Nudibranchs: Scalarane Sesterterpenes from Glossodoris hikuerensis and 12-Acetoxy Dendrillolide A from Goniobranchus albonares.

Two new scalarane sesterterpenes (1, 2) were characterized from an organic extract of a single specimen of the nudibranch Glossodoris hikuerensis collected from Bali. 12-Acetoxy dendrillolide A (10) was identified from specimens of Goniobranchus albonares, while dendrillolide A (11) was isolated both from G. albonares and its sponge diet.

Isolation of norsesterterpenes and spongian diterpenes from Dorisprismatica (= Glossodoris) atromarginata.

Ten new norscalarane metabolites (1-10) with the mooloolabene skeleton in which the C-8 methyl substituent of a scalarane is replaced by a C-7/C-8 double bond are described from the nudibranch Doriprismatica (= Glossodoris) atromarginata and characterized by extensive 1D and 2D NMR studies, together with MS data. Also isolated was the known scalarane 12-deacetoxy-12-oxo-deoxoscalarin together with 26 furanoterpenes, nine of which (11-19) are reported for the first time. The high diversity of chemical compounds and variation between individuals and locations could reflect a varied sponge diet or an enzymatic detoxification mechanism.

Synthesis and determination of the absolute configuration of (-)-(5R,6Z)-dendrolasin-5-acetate from the nudibranch Hypselodoris jacksoni.

A small sample of (-)-(5R,6Z)-dendrolasin-5-acetate, which was fully characterized by 2D NMR studies, was isolated from the nudibranch Hypselodoris jacksoni, along with the sesquiterpenes (+)-agassizin, (-)-furodysinin, (-)-euryfuran, (-)-dehydroherbadysidolide and (+)-pallescensone. A synthetic sample ([α]D -8.7) of the new metabolite was prepared by [1,2]-Wittig rearrangement of a geranylfuryl ether followed by acetylation of purified alcohol isomers.

Psammaplysin derivatives from the Balinese marine sponge Aplysinella strongylata.

Twenty-one new psammaplysin derivatives (4-24) exhibiting a variety of side chains, as well as six previously known psammaplysins, were identified from the Indonesian marine sponge Aplysinella strongylata. The double bond on the side chain of the fatty acid-containing psammaplysins was located by GC-MS analysis of the fatty acid methyl esters and their pyrrolidide derivatives. HPLC and Mosher ester studies confirmed that the isolated metabolites possessing a 19-OH substituent were mixtures of diastereomers.

The 293 K structure of tetradehydrohaliclonacyclamine A.

The polycyclic title compound {systematic name: (1S,16S,17S,31S)-3,20-diazatetracyclo[15.15.0(1,17).