ORCID Profile
0000-0003-4131-4367
Current Organisation
Université de Montréal
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Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.SCITOTENV.2019.135430
Abstract: Protein levels were assessed in the dinoflagellate Lingulodinium polyedra over the course of a diurnal cycle using a label-free LC-MS/MS approach. Roughly 1700 proteins were quantitated in a triplicate dataset over a daily period, and 13 were found to show significant rhythmic changes. Included among the proteins found to be most abundant at night were the two bioluminescence proteins, luciferase and luciferin binding protein, as well as a proliferating cell nuclear protein involved in the nightly DNA replication. Aconitase and a pyrophosphate fructose-6-phosphate-1-phosphotransferase were also found to be more abundant at night, suggestive of an increased ability to generate ATP by glucose catabolism when photosynthesis does not occur. Among the proteins more abundant during the day were found a 2-epi-5-epi-valiolone synthase, potentially involved in synthesis of mycosporin-like amino acids that can act as a "microbial sunscreen", and an enzyme synthesizing vitamin B6 which is known to protect against oxidative stress. A lactate oxidoreductase was also found to be more abundant during the day, perhaps to counteract the pH changes due to carbon fixation by facilitating conversion of pyruvate to lactate. This unbiased proteomic approach reveals novel insights into the daily metabolic changes of this dinoflagellate. Furthermore, the observation that only a limited number of proteins vary support a model where metabolic flux through pathways can be controlled by variations in a select few, possibly rate limiting, steps. Data are available via ProteomeXchange with identifier PXD006994.
Publisher: American Chemical Society (ACS)
Date: 18-09-2009
DOI: 10.1021/PR900475F
Abstract: The formation of harmful algal blooms (HABs) by dinoflagellates has been correlated with the nitrogen load in coastal waters. Nitrogen is implicated as an important factor in the initiation and maintenance of phytoplankton blooms. To characterize the cellular response to nitrogen, 2DE was used to compare protein expressions from dinoflagellates grown under nitrogen depleted and nitrogen replete conditions. A total of 17 differentially expressed protein spots were found, nine of which showed a roughly 16-fold decrease in N-depleted conditions. Five of these nine spots were all identified as isoforms of the plastid Form II ribulose-1,5 bisphosphate carboxylase/oxygenase (Rubisco II), while an additional four protein spots with a molecular weight of 50 kDa were identified as isoforms of a novel protein named nitrogen-associated protein 50 (NAP50). NAP50 was located in the plastids as shown by the presence of an N-terminal plastid targeting leader sequence and by immunohistochemistry. Levels of both Rubisco II and NAP50 decrease sharply between 24 and 36 h following nitrogen depletion and the decrease can be blocked if the N source is replenished before degradation occurs. Both proteins are rapidly resynthesized if the nitrogen source is replenished after degradation has occurred. These results are a first step in the dissection of the behavior of the dinoflagellate proteome under nitrogen stress conditions and may provide new insights into the relationship between dinoflagellate blooms and the nitrogen budget.
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.PROTIS.2011.11.001
Abstract: The dinoflagellate Lingulodinium has a large number of daily rhythms, many of which have no biochemical correlates. We examined the possibility that changes in protein phosphorylation may mediate some of the rhythmic changes by comparing proteins prepared from midday (LD6) and midnight (LD18) cultures. We used two different methods, one a 2D gel protocol in which phosphoproteins were identified after staining with ProQ Diamond, and the other an LC-MS/MS identification of tryptic phosphopeptides that had been purified by TiO(2) chromatography. Two differentially phosphorylated proteins, a light harvesting complex protein and Rad24, were identified using the 2D gel protocol. Six differentially phosphorylated proteins, a polyketide synthase, an uncharacterized transporter, a LIM (actin binding) domain and three RNA binding domain proteins, were identified using the phosphopeptide enrichment protocol. We conclude that changes in protein phosphorylation may underlie some of the rhythmic behavior of Lingulodinium.
No related grants have been discovered for David Morse.