A Metataxonomic Approach Reveals Diversified Bacterial Communities in Antarctic Sponges

Abstract

Marine sponges commonly host a repertoire of bacterial-associated organisms, which significantly contribute to their health and survival by producing several anti-predatory molecules. Many of these compounds are produced by sponge-associated bacteria and represent an incredible source of novel bioactive metabolites with biotechnological relevance. Although most investigations are focused on tropical and temperate species, to date, few studies have described the composition of microbiota hosted by Antarctic sponges and the secondary metabolites that they produce. The investigation was conducted on four sponges collected from two different sites in the framework of the XXXIV Italian National Antarctic Research Program (PNRA) in November–December 2018. Collected species were characterized as Mycale (Oxymycale) acerata, Haliclona (Rhizoniera) dancoi, Hemigellius pilosus and Microxina sarai by morphological analysis of spicules and amplification of four molecular markers. Metataxonomic analysis of these four Antarctic sponges revealed a considerable abundance of Amplicon Sequence Variants (ASVs) belonging to the phyla Proteobacteria, Bacteroidetes, Actinobacteria and Verrucomicrobia. In particular, M. (Oxymycale) acerata, displayed several genera of great interest, such as Endozoicomonas, Rubritalea, Ulvibacter, Fulvivirga and Colwellia. On the other hand, the sponges H. pilosus and H. (Rhizoniera) dancoi hosted bacteria belonging to the genera Pseudhongella, Roseobacter and Bdellovibrio, whereas M. sarai was the sole species showing some strains affiliated to the genus Polaribacter. Considering that most of the bacteria identified in the present study are known to produce valuable secondary metabolites, the four Antarctic sponges could be proposed as potential tools for the discovery of novel pharmacologically active compounds.

Bioactivity Screening of Antarctic Sponges Reveals Anticancer Activity and Potential Cell Death via Ferroptosis by Mycalols

“…The 663 bp PCR fragment (using primer pair dgLCO1490/dgHCO2198) displayed a 100% of pairwise sequence similarity (85% of query cover) to the species Hemimycale topsenti (ex Suberites topsenti ) mitochondrial partial COI gene voucher NIWA28884 (Accession Number: LN850246.1) ( Figure S1 ). The other three sponges were identified in our previous paper [ 7 ] ( Table 1 ).…”

“…Three analyzed sponge specimens were previously identified by morphological and molecular approaches in our previous paper [ 7 ]. All samples belonged to the class Demospongiae and to the following two orders: Haplosclerida with two species, Hemigellius pilosus (Kirkpatrick, 1907) and Haliclona (Rhizoniera) dancoi (Topsent, 1901), and Poecilosclerida with one species, Mycale (Oxymycale) acerata (Kirkpatrick, 1907).…”

“…Sponges were collected by scuba divers in November–December 2018 at two sites of Tethys Bay: (1) M. (Oxymicale) acerata at 26 m of depth (74°42.0670′ S, 164°02.5180′ E) and (2) H. (Rhizoniera) dancoi , H. pilosus and H. topsenti at 28 m of depth (74°40.5370′ S, 164°04.1690′ E). Samples were immediately washed with filtered and sterilized seawater to remove loosely attached bacteria and/or debris [ 7 , 44 ]. A small fragment of each sponge was stored in 70% ethanol for taxonomic identification, another fragment was preserved in RNA later TM into sterile tubes and stored at −20 °C until use for DNA extraction, and the remaining sample was frozen and stored at −80 °C for chemical extraction procedures.…”

“…The current investigation focuses on antiproliferative bioactivity screening of four sponges collected from two different sites in the framework of the XXXIV Italian National Antarctic Research Program (PNRA) in November–December 2018. Three of them have been previously characterized by morphological analysis of spicules and molecular marker (i.e., 18S, 28S, ITS, and CO1) amplification and were identified as Mycale (Oxymycale) acerata Kirkpatrick, 1907, Haliclona (Rhizoniera) dancoi (Topsent, 1901), and Hemigellius pilosus (Kirkpatrick, 1907) [ 7 ].…”

Microbial Diversity of Bacteria Involved in Biomineralization Processes in Mine-Impacted Freshwaters

“…Aliquots of DNAs (30 ng/μl final concentration) were subjected to 16S V3-V4 rRNA gene library preparation and sequencing (Bio-Fab Research, Rome, Italy). Illumina MiSeq Sequencing was performed as described by Ruocco et al (2021) . Briefly, Illumina adapters that overhang nucleotide sequences were added to the gene-specific primer sequences targeting the V3-V4 regions.…”