Diversity and bioactivity of fungi associated with the marine sea cucumber Holothuria poli : disclosing the strains potential for biomedical applications

Abstract

Aims: Identification of the mycobiota associated to the marine echinoderm Holothuria poli and investigation of cytotoxic and pro-osteogenic potential of isolated strains. Methods and results: Fungal strains were isolated from the animal's bodywall, intestine and faeces. The species identification was based on DNA barcoding and morphophysiological observations. Forty-seven species were identified, all are Ascomycota and mainly belonging to Aspergillus and Penicillium genera. Sixteen strains were grown on three media for chemical extraction. Cytotoxic activity was tested on a hepatic cancer cell line (HepG2), the cells viability was evaluated after treatment using a resazurin based assay (AlamarBlue). Pro-osteogenic activity was tested on human Mesenchymal stem cell, differentiation was measured as the alkaline phosphatase production through reaction with p-nitrophenylphosphate or as the cells ability to mineralize calcium using a colorimetric kit (StanBio). Cytotoxic activity was recorded for four fungal species while five of 48 extracts highlighted bioactivity towards human mesenchymal stem cells. Conclusions: The presence of relevant animal-associated mycobiota was observed in H. poli and selected strains showed cytotoxic potential and proosteogenic activity. Significance and Impact of the Study: Our work represents the first report of a Mediterranean Sea cucumber mycobiota and highlights the isolates potential to synthetize compounds of pharmaceutical interest for regenerative medicine.

An Unconventional Flavivirus and Other RNA Viruses in the Sea Cucumber (Holothuroidea; Echinodermata) Virome

“…Fungi do not comprise a large portion of free-living aquatic protistan communities, but they are frequently found in association with invertebrates [ 73 ] and are implicated in at least one invertebrate disease [ 74 ]. Fungi are easily cultivated from echinoderms, and especially holothurian tissues [ 75 , 76 , 77 ], and extracts of holothurian body wall bear antifungal substances [ 78 , 79 ]. To date there have been no cultivation-independent assessments of holothurian microbiome composition.…”

Unveiling Biological Activities of Marine Fungi: The Effect of Sea Salt

“…Some studies have already reported the cytotoxicity evaluation in cancer cell lines of compounds produced by fungal marine species, including Aspergillus, Cladosporium, Penicillium, and Trichoderma [86][87][88]. In fact, marine fungi with the ability to synthesize cytotoxic compounds showed the potential for the treatment of cancer diseases [89]. Further studies using the extracts that did not induce Vero cells mortality are required to evaluate the cytotoxicity on cancer cell lines for cancer research purposes.…”

The Essentials of Marine Biotechnology

“…Around 120 fungal species have been retrieved from sediments of deep-sea hydrothermal vents (Xu et al, 2018). Several other substrates have been investigated for the isolation of marine fungi, however, due to the increasing interest in natural products, the most studied fungal communities are those associated with invertebrates, algae, and plants (Garzoli et al, 2015;Bovio et al, 2017;Gnavi et al, 2017;Raghukumar, 2017;Garzoli et al, 2018;Marchese et al, 2020). Nevertheless, the uncultivable fungi, described by using HTS techniques, still represent the major component of the marine fungal community (Comeau et al, 2016;Rämä et al, 2017;Xu et al, 2018).…”

“…The first reported group of bioactive compounds from marine fungi were cephalosporins, a class of β-lactam antibiotics originally isolated from the Acremonium chrysogenum (which was previously known as Cephalosporium) by Giussepe Brotzu in 1945. Most of the published work on secondary metabolites of marine fungi has focused on a few genera, mainly Penicillium, Aspergillus, Fusarium, and Cladosporium (Imhoff, 2016;Marchese et al, 2020). Marine fungi are found to be a promising source of pharmacologically active metabolites (Imhoff, 2016) with novel anticancer, antibacterial, antiviral, anti-plasmodial, antiinflammatory, but rarely antifouling, activities (Rajasekar et al, 2012;Bovio et al, 2019a).…”