Effects of light quality and nutrient availability on accumulation of mycosporine-like amino acids in Gymnodinium catenatum (Dinophycea)

Vale, Paulo

doi:10.1016/j.jphotobiol.2014.12.016

Cited by 10 publications

(45 citation statements)

References 33 publications

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“…In halogen‐acclimated cells, basal concentration of the major MAAs with a putative osmolyte role (shinorine and porphyra‐334) was low in comparison with previous studies . These cells, collected in June 2016, were preceded by a decade of days with an X‐ray flux equal or below 1.0 B‐level units, lower than the minimal of 2.0 B‐level units found in previous studies.…”

Section: Discussioncontrasting

confidence: 76%

“…MAA levels obtained here for the halogen light source were lower than those observed before . This recent MAA data were obtained in summer 2016, when solar cycle 24 was more advanced in its declining phase.…”

Section: Discussioncontrasting

confidence: 55%

“…It was observed before that MAA concentration was related to solar and geomagnetic activity: MAA concentration was lower when S‐GMA was reduced . The presence of strong UV‐A lines in the fluorescent light spectra is enough to enhance MAA synthesis ; however, these mercury lines are absent in the halogen light spectra (Fig. ).…”

Section: Discussionmentioning

confidence: 84%

“…The cellular concentrations of MAAs were obtained using the molar extinction coefficients reported by previous studies . The instrument's optical path was derived as before (Vale 2016). Extinction coefficients for unknown MAAs were derived from molecules with closest maxima: M‐332 from porphyra‐334 (42 300 m −1 cm −1 ), M‐370 from palythene (50 000 m −1 cm −1 ), M‐324 from palythine (36 200 m −1 cm −1 ) and M‐311 from mycosporine‐glycine (28 100 m −1 cm −1 ).…”

Section: Methodsmentioning

confidence: 99%

“…Absorption in the UV‐A range has been found to be particularly high in cultured G . catenatum when compared to other dinoflagellates , pointing to a high sensitivity toward UV‐A.…”

Section: Introductionmentioning

confidence: 95%

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Resistance to Hydrogen Peroxide Highlights Gymnodinium catenatum (Dinophyceae) Sensitivity to Geomagnetic Activity

Vale

2017

Photochem & Photobiology

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The chain-forming dinoflagellate Gymnodinium catenatum was exposed to hydrogen peroxide. Microscopical examination revealed striking dose-response alterations in chain formation above 245 lM: singlets replaced the dominance of long chain formations. These observations were valid for cells acclimated to halogen light. Under fluorescent light, cells were more resistant to modifications in chain length after H 2 O 2 exposure. Growth along 9 h in the presence of extracellular H 2 O 2 followed an hormesis response in both light regimes. Under halogen light conditions, alterations in chain formation and net growth were related to culture time, inocula concentration and geomagnetic activity (GMA) in the proceeding hours. Below a 16 nT threshold in GMA average growth was 0%, while above 16 nT it was circa +9%, independently if the local static magnetic field was altered by a permanent magnet or not. Mycosporine-like amino acids that can have an antioxidant role and are easily oxidized decreased from 7.1 to 6.5 pg cell À1 (P < 0.05) under halogen light and exposure to 245 lM H 2 O 2 . GMA, as well as UV-A, increased stress responsiveness that can momentarily protect cells from extracellular H 2 O 2 addition. However, stress response is dependent on bio-availability of several micronutrients and macronutrients, many found at limiting concentrations in oceanic waters.

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Section: Discussioncontrasting

confidence: 76%

Section: Discussioncontrasting

confidence: 55%

Section: Discussionmentioning

confidence: 84%

Section: Methodsmentioning

confidence: 99%

“…Absorption in the UV‐A range has been found to be particularly high in cultured G . catenatum when compared to other dinoflagellates , pointing to a high sensitivity toward UV‐A.…”

Section: Introductionmentioning

confidence: 95%

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