Bioactive Potential of Two Marine Picocyanobacteria Belonging to Cyanobium and Synechococcus Genera.

Patrizia Pagliara,Giuseppe Egidio De Benedetto,Matteo Francavilla,Carmela Caroppo,Amilcare Barca

doi:10.3390/microorganisms9102048

Patrizia Pagliara, Giuseppe Egidio De Benedetto + Show 3 more

Open Access

https://doi.org/10.3390/microorganisms9102048

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Abstract

Coccoid cyanobacteria produce a great variety of secondary metabolites, which may have useful properties, such as antibacterial, antiviral, anticoagulant or anticancer activities. These cyanobacterial metabolites have high ecological significance, and they could be considered responsible for the widespread occurrence of these microorganisms. Considering the great benefit derived from the identification of competent cyanobacteria for the extraction of bioactive compounds, two strains of picocyanobacteria (coccoid cyanobacteria < 3 µm) (Cyanobium sp. ITAC108 and Synechococcus sp. ITAC107) isolated from the Mediterranean sponge Petrosia ficiformis were analyzed. The biological effects of organic and aqueous extracts from these picocyanobacteria toward the nauplii of Artemia salina, sea urchin embryos and human cancer lines (HeLa cells) were evaluated. Methanolic and aqueous extracts from the two strains strongly inhibited larval development; on the contrary, in ethyl acetate and hexane extracts, the percentage of anomalous embryos was low. Moreover, all the extracts of the two strains inhibited HeLa cell proliferation, but methanol extracts exerted the highest activity. Gas chromatography–mass spectrometry analysis evidenced for the first time the presence of β-N-methylamino-l-alanine and microcystin in these picocyanobacteria. The strong cytotoxic activity observed for aqueous and methanolic extracts of these two cyanobacteria laid the foundation for the production of bioactive compounds of pharmacological interest.

Highlights

Picocyanobacteria (PCCs) (0.2–3 μm) [1] are a conspicuous component of the phytoplankton communities
The highest yields were found using methanol, but different values were observed between the strain Synechococcus sp
MS-DIAL, methanolic and aqueous extracts were considered as different classes

Summary

Introduction

Picocyanobacteria (PCCs) (0.2–3 μm) [1] are a conspicuous component of the phytoplankton communities. The most represented genera are Synechococcus, Synechocystis, Cyanobium, Cyanobacterium [7] and Prochlorococcus [8]. PCCs can be detected both in the free-living population in the water column and associated with other organisms (foraminifers, corals, sponges, mollusks) or substrates [9]. PCCs may contribute significantly (i.e., up to 50%) to phytoplankton productivity and biomass in marine waters [10] and they can be responsible for up to 98% of the total biomass in brackish systems [11,12]. PCCs play an important role in the functioning of the microbial loop [13,14], and they actively participate in the modulation of energy and matter flows as well as in the sustenance and development of higher trophic levels [15,16]

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