Diatoms, a class of unicellular microalgae that play a crucial role in aquatic ecosystems, are widely recognized for their ability to produce a diverse array of chemical metabolites with significant ecological roles, including communication, stress response, and defense. In our previous works, we explored the biotechnological potential of a brackish diatom, initially identified as Staurosirella pinnata (Ehrenberg) D.M. Williams & Round, isolated from a biofilm in the sediments of the Cabras Lagoon (Sardinia, Italy). This diatom was mass-cultivated in 8L indoor photobioreactors under controlled conditions (25 °C, irradiance of 80 μmol photons m⁻² s⁻¹, and a 12:12 h light/dark cycle). Our investigations revealed that this diatom exhibited remarkable bioactivity, with cytotoxic properties against a diverse range of biological targets. Specifically, it demonstrated significant effects on human medulloblastoma and melanoma cells, viruses such as the Sendai paramyxovirus and H1N1-Wisconsin Influenza A virus, embryos of the Mediterranean Sea urchin (Paracentrotus lividus), and even the heterocystic cyanobacterium Trichormus variabilis, which coexisted in the same biofilm. These findings underscored the diatom’s role as a ‘natural killer,’ attributed to its ability to produce bioactive compounds, including oxylipins with notable allelopathic effects. To better identify this microorganism, an integrative taxonomy approach was employed, combining morphological and molecular analyses. High-resolution scanning electron microscopy (SEM) revealed distinctive ultrastructural features, including valve morphology and striae pattern, that were inconsistent with the original classification as Staurosirella pinnata. Also, the molecular analyses, based on 18S rRNA and rbcL genes, indicated that this diatom belongs to the recently described genus Gedaniella Chunlian Li et al., and, more in particular, to the species Gedaniella flavovirens (H.Takano) Chunlian Li et al. Our findings highlight the importance of an integrative taxonomy approach to achieve accurate species identification also in diatoms, contemporarily providing new insights into their diversity and bioactive potentials.
Unmasking a ‘killer’: an interdisciplinary quest to profile the diatom we call Staurosirella pinnata.
Sciuto K.;
2025
Abstract
Diatoms, a class of unicellular microalgae that play a crucial role in aquatic ecosystems, are widely recognized for their ability to produce a diverse array of chemical metabolites with significant ecological roles, including communication, stress response, and defense. In our previous works, we explored the biotechnological potential of a brackish diatom, initially identified as Staurosirella pinnata (Ehrenberg) D.M. Williams & Round, isolated from a biofilm in the sediments of the Cabras Lagoon (Sardinia, Italy). This diatom was mass-cultivated in 8L indoor photobioreactors under controlled conditions (25 °C, irradiance of 80 μmol photons m⁻² s⁻¹, and a 12:12 h light/dark cycle). Our investigations revealed that this diatom exhibited remarkable bioactivity, with cytotoxic properties against a diverse range of biological targets. Specifically, it demonstrated significant effects on human medulloblastoma and melanoma cells, viruses such as the Sendai paramyxovirus and H1N1-Wisconsin Influenza A virus, embryos of the Mediterranean Sea urchin (Paracentrotus lividus), and even the heterocystic cyanobacterium Trichormus variabilis, which coexisted in the same biofilm. These findings underscored the diatom’s role as a ‘natural killer,’ attributed to its ability to produce bioactive compounds, including oxylipins with notable allelopathic effects. To better identify this microorganism, an integrative taxonomy approach was employed, combining morphological and molecular analyses. High-resolution scanning electron microscopy (SEM) revealed distinctive ultrastructural features, including valve morphology and striae pattern, that were inconsistent with the original classification as Staurosirella pinnata. Also, the molecular analyses, based on 18S rRNA and rbcL genes, indicated that this diatom belongs to the recently described genus Gedaniella Chunlian Li et al., and, more in particular, to the species Gedaniella flavovirens (H.Takano) Chunlian Li et al. Our findings highlight the importance of an integrative taxonomy approach to achieve accurate species identification also in diatoms, contemporarily providing new insights into their diversity and bioactive potentials.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
