Physiological responses of <i>Chaetoceros</i> sp. and <i>Nannochloropsis</i> sp. to short-term 2, 4-D, dimethylamine and endosulfan exposure

Hii, Yii Siang; Shia, Kwee Luan; Chuah, Tse Seng; Hing, Lee Siang

doi:10.1080/14634980903347662

Cited by 5 publications

(1 citation statement)

References 14 publications

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“…BECs (Arzul et al, 1999;Lelong et al, 2011;Weissbach et al, 2010), its ubiquity in phytoplankton communities (Dalsgaard et al, 2003) and its co-occurrence with A. minutum blooms (Chapelle et al, 2014;Klein et al, in prep). Moreover the genus Chaetoceros is a microalgal model commonly used in ecotoxicological studies (Desai et al, 2006;Hii et al, 2009;Hourmant et al, 2009). The bioassay was conceived to be applied to microalgal cultures, extracts or field samples.…”

Section: Introductionmentioning

confidence: 99%

A rapid quantitative fluorescence-based bioassay to study allelochemical interactions from Alexandrium minutum

Long

Tallec

Soudant

et al. 2018

Environmental Pollution

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Harmful microalgal blooms are a threat to aquatic organisms, ecosystems and human health. Toxic dinoflagellates of the genus Alexandrium are known to produce paralytic shellfish toxins and to release bioactive extracellular compounds (BECs) with potent cytotoxic, hemolytic, ichtyotoxic and allelopathic activity. Negative allelochemical interactions refer to the chemicals that are released by the genus Alexandrium and that induce adverse effects on the physiology of co-occurring protists and predators. Releasing BECs gives the donor a competitive advantage that may help to form dense toxic blooms of phytoplankton. However BECs released by Alexandrium minutum are uncharacterized and it is impossible to quantify them using classical chemical methods. Allelochemical interactions are usually quantified through population growth inhibition or lytic-activity based bioassays using a secondary target organism. However these bioassays require time (for growth or microalgal counts) and/or are based on lethal effects. The use of pulse amplitude modulation (PAM) fluorometry has been widely used to assess the impact of environmental stressors on phytoplankton but rarely for allelochemical interactions. Here we evaluated the use of PAM and propose a rapid chlorophyll fluorescence based bioassay to quantify allelochemical BECs released from Alexandrium minutum. We used the ubiquitous diatom Chaetoceros muelleri as a target species. The bioassay, based on sub-lethal effects, quantifies allelochemical activity from different samples (filtrates, extracts in seawater) within a short period of time (2 h). This rapid bioassay will help investigate the role of allelochemical interactions in Alexandrium bloom establishment. It will also further our understanding of the potential relationship between allelochemical activities and other cytotoxic activities from BECs. While this bioassay was developed for the species A. minutum, it may be applicable to other species producing allelochemicals and may provide further insights into the role and impact of allelochemical interactions in forming dense algal blooms and structuring marine ecosystems.

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Section: Introductionmentioning

confidence: 99%

A rapid quantitative fluorescence-based bioassay to study allelochemical interactions from Alexandrium minutum

Long

Tallec

Soudant

et al. 2018

Environmental Pollution

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Monoculture and co-culture tests of the toxicity of four typical herbicides on growth, photosynthesis and oxidative stress responses of the marine diatoms Pseudo-nitzschia mannii and Chaetoceros decipiens

et al. 2022

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The toxicity of four herbicides in mixture (alachlor, diuron, des-isopropyl-atrazine and 31 simazine) on the growth and the photosynthesis parameters of two marine diatoms Pseudo-32 niszchia mannii and Chaetoceros decipiens have been investigated for 9 days in monoculture 33 and co-culture tests. The catalase (CAT) and guaiacol peroxidase (GPX) were also monitored 34 to assess the oxidative stress response. In single-species assays, while both species displayed 35 no affected instantaneous growth rate by herbicides, their physiological responses were 36 different. Chl a content of P. mannii significantly decreased upon herbicide exposure, due 37 probably to pigment destruction or inhibition of their synthesis. This decrease was associated 38 with a reduction in the chlorophyll fluorescence parameters (ABS0/RC, TR0/RC, ET0/RC and 39 DI0/RC). In contrast, C. decipiens maintained an effective photosynthetic performance under 40 herbicide exposure, as Chl a per cell content and the specific energy fluxes per reaction center 41 remained unchanged relative to control values. GPX activity was significantly higher in 42 contaminated P. mannii and C. decipiens monocultures than in controls at early herbicide 43 exposure (1 day), whereas a significant induction of CAT activity occurred later (from day 3 44 for C. decipiens and at day 9 for P. mannii) in response to herbicides. In control co-culture, P.45 mannii was eliminated by C. decipiens. As observed in the monoculture, the herbicides did not 46 affect the photosynthetic performance of C. decipiens in co-culture, but significantly reduced 47 its instantaneous growth rate. The oxidative stress response in co-culture has similar trends to 48 that of C. decipiens in monoculture, but the interspecies competition likely resulted in higher 49 CAT activity under herbicide exposure. Results of this study suggest that herbicide toxicity for 50 marine diatoms might be amplified by interspecies interactions in natural communities, which 51 might lead to different physiological and growth responses.

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Sensitivity of selected tropical microalgae isolated from a farmland and a eutrophic lake to atrazine and endosulfan

et al. 2019

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Physiological responses of Chaetoceros sp. and Nannochloropsis sp. to short-term 2, 4-D, dimethylamine and endosulfan exposure

Cited by 5 publications

References 14 publications

A rapid quantitative fluorescence-based bioassay to study allelochemical interactions from Alexandrium minutum

A rapid quantitative fluorescence-based bioassay to study allelochemical interactions from Alexandrium minutum

Monoculture and co-culture tests of the toxicity of four typical herbicides on growth, photosynthesis and oxidative stress responses of the marine diatoms Pseudo-nitzschia mannii and Chaetoceros decipiens

Sensitivity of selected tropical microalgae isolated from a farmland and a eutrophic lake to atrazine and endosulfan

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