Does the Chemical Diversity of the Order Haplosclerida (Phylum Porifera: Class Demospongia) Fit with Current Taxonomic Classification?

Abstract

Sponges and their associated microbiota are well known to produce a large diversity of natural products, also called specialized metabolites. In addition to their potential use in the pharmaceutical industry, these rather species-specific compounds may help in the classification of some particular sponge groups. We review herein compounds isolated from haplosclerid sponges (Class Demospongia, Order Haplosclerida) in order to help in the revision of this large group of marine invertebrates. We focus only on 3-alkylpyridine derivatives and polyacetylenic compounds, as these two groups of natural products are characteristic of haplosclerid species and are highly diverse. A close collaboration between chemists and biologists is required in order to fully apply chemotaxonomical approaches, and whenever possible biological data should include morphological and molecular data and some insight into their microbial abundance.

Assessing the Zoantharian Diversity of the Tropical Eastern Pacific through an Integrative Approach

“…For instance, the structurally complex and extremely toxic palytoxin was isolated from a zoantharian of the genus Palythoa 42 , 43 . The usual natural product chemistry approach is clearly not satisfactory for systematics due to a skewed and more pharmaceutically driven process precluding the emergence of chemotaxonomy, and a broader vision of the metabolic content is required 44 . The recent development of environmental metabolomics based on Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) paved the way for a broader coverage of the metabolites produced by a single organism or cell in a short period of time and with high sensitivity, avoiding the long and tedious process of isolation and identification of the metabolites.…”

“…The recent development of environmental metabolomics based on Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS) paved the way for a broader coverage of the metabolites produced by a single organism or cell in a short period of time and with high sensitivity, avoiding the long and tedious process of isolation and identification of the metabolites. Metabolomic approaches were recently applied to some groups of sponges and cnidarians providing valuable insights into their classifications 21 , 44 – 47 . For example, a HPLC-MS untargeted metabolomic approach applied to the classification of Mediterranean Homoscleromorpha sponges yielded data well correlated to phylogenetic analyses 46 .…”

Metabolome variability for two Mediterranean sponge species of the genus Haliclona: specificity, time, and space

“…Haplosclerids are an important group of sponges in terms of diversity and production of bioactive compounds. However, their taxonomy remains challenging due to major discrepancies between morphological and molecular data (Redmond et al 2011;Tribalat et al 2016). Molecular data indicates that many very distant related species have been placed in the genus Haliclona, that may even be polyphyletic (organisms that do not share a common ancestor), and re-examination of the systematics of the group Haploscerids is urgently needed (Tribalat et al 2016;Redmond et al 2011).…”

“…However, their taxonomy remains challenging due to major discrepancies between morphological and molecular data (Redmond et al 2011;Tribalat et al 2016). Molecular data indicates that many very distant related species have been placed in the genus Haliclona, that may even be polyphyletic (organisms that do not share a common ancestor), and re-examination of the systematics of the group Haploscerids is urgently needed (Tribalat et al 2016;Redmond et al 2011). Integrative taxonomy is a concept that is growing in popularity among taxonomists and consists in a combination of several independent datasets for the classification of species: morphology, anatomy, cytology, spicule shapes, reproduction, molecular data, chemical information etc.…”

“…Within the class Demospongiae, several sponges of the order Haplosclerida are considered as prolific sources of bioactive marine natural products. In particular, species from the genus Haliclona (family Chalinidae) have attracted much attention due to the high diversity of species and the variety of specialized metabolites they contain (Tribalat et al 2016). Importantly, the systematics of this genus and more generally the Haplosclerida group is being revised deeply.…”