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

Marine natural products.

Donor-acceptor-substituted cyclopropane derivatives and their application in organic synthesis.

Ruthenium-Catalyzed Reactions for Organic Synthesis.

Lipids of aquatic organisms as potential contributors to lacustrine sediments—II☆

Chemical fossils discovered in sedimentary rocks in Oman provide the earliest evidence for animal life so far discovered. The fossil steroids — 24-isopropylcholestanes characteristic of sponges of the Demospongiae class — date back 635 million years or more to around the time of the Marinoan glaciation, the last of the immense ice ages at the end of the Neoproterozoic. This suggests that the shallow waters in some late Cryogenian ocean basins contained dissolved oxygen in concentrations sufficient to support simple multicellular organisms at least 100 million years before the rapid diversification of bilaterians during the Cambrian explosion. This paper reports chemical fossils characteristic of sponges that date back at least 635 million years ago, constituting the earliest evidence yet found for animal life. The sponges lived during the Marinoan glaciation, the last of the immense ice ages at the end of the Neoproterozoic. No evidence has been found for animal life during the earlier Sturtian glaciation. The Neoproterozoic era (1,000–542 Myr ago) was an era of climatic extremes and biological evolutionary developments culminating in the emergence of animals (Metazoa) and new ecosystems1. Here we show that abundant sedimentary 24-isopropylcholestanes, the hydrocarbon remains of C30 sterols produced by marine demosponges, record the presence of Metazoa in the geological record before the end of the Marinoan glaciation (∼635 Myr ago). These sterane biomarkers are abundant in all formations of the Huqf Supergroup, South Oman Salt Basin, and, based on a new high-precision geochronology2, constitute a continuous 100-Myr-long chemical fossil record of demosponges through the terminal Neoproterozoic and into the Early Cambrian epoch. The demosponge steranes occur in strata that underlie the Marinoan cap carbonate (>635 Myr ago). They currently represent the oldest evidence for animals in the fossil record, and are evidence for animals pre-dating the termination of the Marinoan glaciation. This suggests that shallow shelf waters in some late Cryogenian ocean basins (>635 Myr ago) contained dissolved oxygen in concentrations sufficient to support basal metazoan life at least 100 Myr before the rapid diversification of bilaterians during the Cambrian explosion. Biomarker analysis has yet to reveal any convincing evidence for ancient sponges pre-dating the first globally extensive Neoproterozoic glacial episode (the Sturtian, ∼713 Myr ago in Oman2).

/pdf/fossil-steroids-record-the-appearance-of-demospongiae-during-4zy2b0kc5a.pdf

Fossil steroids record the appearance of Demospongiae during the Cryogenian period

Four new trihydroxylated sterols from the sponge Spongionella gracilis

Scalarin, a new pentacyclic C-25 terpenoid from the sponge Cacospongia scalaris

The fatty acyl components of the phospholipids from the spongePetrosia ficiformis consisted predominantly of branched, especially iso and anteiso acids. The two major components of the complex mixture are the hitherto unknown Z,Z-25-methyl-5,9-hexacosadienoic and Z,Z-24-methyl-5,9-hexacosadienoic acids. Other unknown acids are: 7,13,16-docosatrienoic acid, 15-methyldocosanoic acid, 15-methyltricosanoic acid and 24-methyl-5,9-pentacosadienoic acid. Short branched-chain fatty acids, presumably of bacterial origin, are considered to be the possible bioprecursors of these novel phospholipid constituents. The major phospholipids were PE, PC, PG, PS and PI. The distribution of fatty acids among the phospholipid classes was also studied.

Donato Sica

Papers

Four new trihydroxylated sterols from the sponge Spongionella gracilis

Scalarin, a new pentacyclic C-25 terpenoid from the sponge Cacospongia scalaris

Phospholipid studies of marine organisms: III. New phospholipid fatty acids fromPetrosia ficiformis

Axisonitrile-3, axisothiocyanate-3 and axamide-3. Sesquiterpenes with a novel spiro[4,5]decane skeleton from the sponge Axinella cannabina☆

Secosteroids of marine origin