Isolation and Characterization of Photosensitive Hemolytic Toxins from the Mixotrophic Dinoflagellate <i>Akashiwo sanguinea</i>

The mixotrophic dinoflagellate <i>Akashiwo sanguinea</i> is known to have acute toxic effects on multiple marine organisms, while the composition and chemical properties of its toxins remain unclear. In this study, we established a method for separation and purification of <i>A. sa...

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Main Authors: Jiling Pan, Ting Fang, Shuang Xie, Ning Xu, Ping Zhong
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Marine Drugs
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Online Access:https://www.mdpi.com/1660-3397/23/4/153
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author Jiling Pan
Ting Fang
Shuang Xie
Ning Xu
Ping Zhong
author_facet Jiling Pan
Ting Fang
Shuang Xie
Ning Xu
Ping Zhong
author_sort Jiling Pan
collection DOAJ
description The mixotrophic dinoflagellate <i>Akashiwo sanguinea</i> is known to have acute toxic effects on multiple marine organisms, while the composition and chemical properties of its toxins remain unclear. In this study, we established a method for separation and purification of <i>A. sanguinea</i> toxins using chromatographic techniques. The acetone extract of <i>A. sanguinea</i> exhibited higher hemolytic activity and shorter incubation time compared to methanol and ethyl acetate extracts. Five fractions were obtained by solid-phase extraction (SPE), of which SPE3 (acetone/water ratio 3:2) and SPE4 (acetone/water ratio 4:1) exhibited the highest hemolytic activities and allelopathic effects. Further purification on SPE3 and SPE4 using reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with a diode array detector (DAD) resulted in 11 subfractions, among which Fr4-5 displayed the strongest hemolytic activity. Nearly all active subfractions exhibited higher hemolytic activities incubated under light than those in the dark (<i>p</i> < 0.05), suggesting that <i>A. sanguinea</i> can produce both photosensitive and non-photosensitive toxins, with the former being the primary contributors to its hemolytic activity. Molecular characterization by UV-Vis, FTIR, and HRMS/MS analysis revealed that the structural features of Fr4-5 were highly consistent with porphyrin analogs and could be derived from chlorophyll <i>c</i>-related precursors. These findings highlight that the photosensitive toxins in <i>A. sanguinea</i> may serve dual roles in stress adaptation and ecological competition, potentially contributing to the formation of the blooms.
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spelling doaj-art-d6f01c9ccb0247d380caf69e5b3dba8f2025-08-20T03:13:55ZengMDPI AGMarine Drugs1660-33972025-03-0123415310.3390/md23040153Isolation and Characterization of Photosensitive Hemolytic Toxins from the Mixotrophic Dinoflagellate <i>Akashiwo sanguinea</i>Jiling Pan0Ting Fang1Shuang Xie2Ning Xu3Ping Zhong4Institute of Hydrobiology/Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, ChinaInstitute of Hydrobiology/Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, ChinaInstitute of Hydrobiology/Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, ChinaInstitute of Hydrobiology/Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, ChinaInstitute of Hydrobiology/Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, ChinaThe mixotrophic dinoflagellate <i>Akashiwo sanguinea</i> is known to have acute toxic effects on multiple marine organisms, while the composition and chemical properties of its toxins remain unclear. In this study, we established a method for separation and purification of <i>A. sanguinea</i> toxins using chromatographic techniques. The acetone extract of <i>A. sanguinea</i> exhibited higher hemolytic activity and shorter incubation time compared to methanol and ethyl acetate extracts. Five fractions were obtained by solid-phase extraction (SPE), of which SPE3 (acetone/water ratio 3:2) and SPE4 (acetone/water ratio 4:1) exhibited the highest hemolytic activities and allelopathic effects. Further purification on SPE3 and SPE4 using reverse-phase high-performance liquid chromatography (RP-HPLC) coupled with a diode array detector (DAD) resulted in 11 subfractions, among which Fr4-5 displayed the strongest hemolytic activity. Nearly all active subfractions exhibited higher hemolytic activities incubated under light than those in the dark (<i>p</i> < 0.05), suggesting that <i>A. sanguinea</i> can produce both photosensitive and non-photosensitive toxins, with the former being the primary contributors to its hemolytic activity. Molecular characterization by UV-Vis, FTIR, and HRMS/MS analysis revealed that the structural features of Fr4-5 were highly consistent with porphyrin analogs and could be derived from chlorophyll <i>c</i>-related precursors. These findings highlight that the photosensitive toxins in <i>A. sanguinea</i> may serve dual roles in stress adaptation and ecological competition, potentially contributing to the formation of the blooms.https://www.mdpi.com/1660-3397/23/4/153harmful algal bloomhemolytic activityphotosensitive toxinphotosynthetic pigmentchromatographymass spectrometry
spellingShingle Jiling Pan
Ting Fang
Shuang Xie
Ning Xu
Ping Zhong
Isolation and Characterization of Photosensitive Hemolytic Toxins from the Mixotrophic Dinoflagellate <i>Akashiwo sanguinea</i>
Marine Drugs
harmful algal bloom
hemolytic activity
photosensitive toxin
photosynthetic pigment
chromatography
mass spectrometry
title Isolation and Characterization of Photosensitive Hemolytic Toxins from the Mixotrophic Dinoflagellate <i>Akashiwo sanguinea</i>
title_full Isolation and Characterization of Photosensitive Hemolytic Toxins from the Mixotrophic Dinoflagellate <i>Akashiwo sanguinea</i>
title_fullStr Isolation and Characterization of Photosensitive Hemolytic Toxins from the Mixotrophic Dinoflagellate <i>Akashiwo sanguinea</i>
title_full_unstemmed Isolation and Characterization of Photosensitive Hemolytic Toxins from the Mixotrophic Dinoflagellate <i>Akashiwo sanguinea</i>
title_short Isolation and Characterization of Photosensitive Hemolytic Toxins from the Mixotrophic Dinoflagellate <i>Akashiwo sanguinea</i>
title_sort isolation and characterization of photosensitive hemolytic toxins from the mixotrophic dinoflagellate i akashiwo sanguinea i
topic harmful algal bloom
hemolytic activity
photosensitive toxin
photosynthetic pigment
chromatography
mass spectrometry
url https://www.mdpi.com/1660-3397/23/4/153
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AT tingfang isolationandcharacterizationofphotosensitivehemolytictoxinsfromthemixotrophicdinoflagellateiakashiwosanguineai
AT shuangxie isolationandcharacterizationofphotosensitivehemolytictoxinsfromthemixotrophicdinoflagellateiakashiwosanguineai
AT ningxu isolationandcharacterizationofphotosensitivehemolytictoxinsfromthemixotrophicdinoflagellateiakashiwosanguineai
AT pingzhong isolationandcharacterizationofphotosensitivehemolytictoxinsfromthemixotrophicdinoflagellateiakashiwosanguineai