Ribosomal DNA Sequence-Based Taxonomy and Antimicrobial Activity of Prorocentrum spp. (Dinophyceae) from Mauritius Coastal Waters, South-West Indian Ocean

Abstract

Microalgae are unicellular organisms and commonly present in the euphotic zone of marine ecosystems. From the western coast of Mauritius, three strains of Prorocentrum species were isolated from macrophytes and cultured under standard laboratory conditions. Morphologies were examined by light, fluorescence, and scanning electron microscopy, and phylogenetic analyses were based on partial large subunit LSU rDNA (D1-D2) and ITS1-5.8S-ITS2 (ITS) regions. Three Prorocentrum species, including the P. fukuyoi complex, P. rhathymum, and P. lima complex, were identified. The antimicrobial activities were assayed against potential human pathogenic bacterial strains. The highest zone of inhibition was recorded for intracellular and extracellular protein extracts of Prorocentrum rhathymum against Vibrio parahaemolyticus. The polysaccharide extracts of the Prorocentrum fukuyoi complex had a higher zone of inhibition (24 ± 0.4 mm) against MRSA at a minimum concentration of 0.625 μg/mL. The extracts from the three Prorocentrum species had different levels of activity against the pathogens used, and this can be of scientific interest in the search for antibiotics from natural marine sources.

Screening of Microalgae for Bioactivity with Antiviral, Antibacterial, Anti-Inflammatory and Anti-Cancer Assays

“…This result is in line with a strong antibacterial activity of extracts being reported for other dinoflagellates (P. lima, Dinophysis fortii and Gambierdiscus sp.) against several bacteria and fungi (Aspergillus niger, Penicillium funiculosum, Candida rugosa, Escherichia coli, Bacillus megaterium and Staphylococcus aureus) [84,85]. The extracts obtained from H. minima (E08) and Karlodinium veneficum (E17) also showed a higher activity against the Gram (+) M. luteus than the Gram (−) A. hydrophyla, as was previously found for H. circularisquama and K. micrum using other bacterial species [86,87].…”