Six marine thecate Heterocapsa (Dinophyceae) from Malaysia, including the description of three novel species and their cytotoxicity potential
Document Type
Article
Publication Date
12-1-2022
Abstract
Thirty-four strains of Heterocapsa were established from Malaysian waters and their morphologies were exam-ined by light, scanning, and transmission electron microscopy. Three species, H. bohaiensis, H. huensis, and H. rotundata, and three new species, H. borneoensis sp. nov., H. limii sp. nov., and H. iwatakii sp. nov. were described in this study. The three species were differentiated morphologically by unique characteristics of cell size, shape, displacement of the cingulum, shape and position of nucleus, the number and position of pyrenoids, and body scale ultrastructure. The species delimitations were robustly supported by the molecular data. A light-microscopy-based key to species of Heterocapsa is established, with two major groups, i.e., species with a single pyrenoid, and species with multiple pyrenoids. Bioassays were conducted by exposing Artemia nauplii to Het-erocapsa densities of 1-5 x 105 cells mL-1, and treatments exposed to H. borneoensis showed naupliar mortality, while no naupliar death was observed in the treatments exposed to cells of H. bohaiensis, H. huensis, H. limii, and H. iwatakii. Naupliar death was observed during the initial 24 h for both tested H. borneoensis strains, and mortality rates increased up to 50% after 72-h exposure. This study documented for the first time the diversity and cytotoxic potency of Heterocapsa species from Malaysian waters.
Keywords
Body scales, Cytotoxicity, Heterocapsa, ITS2 transcript, LSU rDNA, SSU rDNA
Divisions
ocean
Funders
Ministry of Education, Malaysia [RACER/1/2019/STG03/UNIMAS//1],Ministry of Education, Malaysia [LRGS/1/2020/UMT/01/1/3],Ministry of Education, Malaysia [IOES-2014C]
Publication Title
HARMFUL ALGAE
Volume
120
Publisher
ELSEVIER
Publisher Location
RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS