Brevetoxin (PbTx-2) influences the redox status and NPQ of Karenia brevis by way of thioredoxin reductase

Chen, Wei; Colon, Ricardo; Louda, J. William; Rey, Freddy Rodriguez del; Durham, Michaella; Rein, Kathleen S.

doi:10.1016/j.hal.2017.11.004

Cited by 11 publications

(8 citation statements)

References 67 publications

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“…Another proposed role for a toxin is mediating redox potential by brevetoxin in the chloroplast of Karenia brevis . 90 This helps explain why complex polyketides are found in photosynthetic species as well as the apparent association between function and synthesis in the chloroplast since it is a major source of redox stress. Thus, focusing on “toxin” synthesis may not be advantageous in the long run versus understanding the modular synthases in dinoflagellates as a whole and their biological role within dinoflagellates.…”

Section: Discussionmentioning

confidence: 99%

A Global Approach to Estimating the Abundance and Duplication of Polyketide Synthase Domains in Dinoflagellates

Williams

Bachvaroff

Place

2021

Evol Bioinform Online

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Many dinoflagellate species make toxins in a myriad of different molecular configurations but the underlying chemistry in all cases is presumably via modular synthases, primarily polyketide synthases. In many organisms modular synthases occur as discrete synthetic genes or domains within a gene that act in coordination thus forming a module that produces a particular fragment of a natural product. The modules usually occur in tandem as gene clusters with a syntenic arrangement that is often predictive of the resultant structure. Dinoflagellate genomes however are notoriously complex with individual genes present in many tandem repeats and very few synthetic modules occurring as gene clusters, unlike what has been seen in bacteria and fungi. However, modular synthesis in all organisms requires a free thiol group that acts as a carrier for sequential synthesis called a thiolation domain. We scanned 47 dinoflagellate transcriptomes for 23 modular synthase domain models and compared their abundance among 10 orders of dinoflagellates as well as their co-occurrence with thiolation domains. The total count of domain types was quite large with over thirty-thousand identified, 29 000 of which were in the core dinoflagellates. Although there were no specific trends in domain abundance associated with types of toxins, there were readily observable lineage specific differences. The Gymnodiniales, makers of long polyketide toxins such as brevetoxin and karlotoxin had a high relative abundance of thiolation domains as well as multiple thiolation domains within a single transcript. Orders such as the Gonyaulacales, makers of small polyketides such as spirolides, had fewer thiolation domains but a relative increase in the number of acyl transferases. Unique to the core dinoflagellates, however, were thiolation domains occurring alongside tetratricopeptide repeats that facilitate protein-protein interactions, especially hexa and hepta-repeats, that may explain the scaffolding required for synthetic complexes capable of making large toxins. Clustering analysis for each type of domain was also used to discern possible origins of duplication for the multitude of single domain transcripts. Single domain transcripts frequently clustered with synonymous domains from multi-domain transcripts such as the BurA and ZmaK like genes as well as the multi-ketosynthase genes, sometimes with a large degree of apparent gene duplication, while fatty acid synthesis genes formed distinct clusters. Surprisingly the acyl-transferases and ketoreductases involved in fatty acid synthesis (FabD and FabG, respectively) were found in very large clusters indicating an unprecedented degree of gene duplication for these genes. These results demonstrate a complex evolutionary history of core dinoflagellate modular synthases with domain specific duplications throughout the lineage as well as clues to how large protein complexes can be assembled to synthesize the largest natural products known.

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Section: Discussionmentioning

confidence: 99%

A Global Approach to Estimating the Abundance and Duplication of Polyketide Synthase Domains in Dinoflagellates

Williams

Bachvaroff

Place

2021

Evol Bioinform Online

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“…If this were true, then strains that differ in cellular toxin loads should have observable differences in biochemical parameters related to redox status, and this is indeed the case. Low toxin producing K. brevis has been consistently shown to have higher cellular thiol content including a higher level of reduced cysteine in the proteome when compared to a high toxin producing strain . Recently reported redox proteomics studies using cysteine reactive tandem mass tags have identified significant differences in the redox status of the proteomes of high and low toxin strains of K. brevis with the high toxin proteome in a more oxidized state .…”

Section: Discussionmentioning

confidence: 99%

“…It is also possible that this is a mechanism of allelopathy for K. brevis , by interfering with redox regulation of algal competitors that lack a mechanism to compensate for the inhibition of TrxR. It is perhaps noteworthy that several different homologues of NADPH-dependent TrxR have been identified in the K. brevis transcriptome library, possibly a result of the complex evolutionary origins of the K. brevis chloroplast . These homologues may differ in sensitivity to PbTx-2.…”

Section: Discussionmentioning

confidence: 99%

“…TrxR, which is essential to maintaining redox homeostasis within the cell via Trx, is present in all organisms; thus numerous orthologs of TrxR have evolved. High molecular weight TrxRs (∼55 kDa), which are widespread and found in vertebrates, invertebrates, insects, and protists, including K. brevis , are homodimers containing the rare “21st amino acid” selenocysteine (Sec). The two subunits of Sec-containing TrxRs are arranged such that the reducing equivalents of NADPH are shuttled via FAD to an N-terminal disulfide and finally to a C-terminal seleno-sulfide of the other monomer.…”

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confidence: 99%

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The Marine Neurotoxin Brevetoxin (PbTx-2) Inhibits Karenia brevis and Mammalian Thioredoxin Reductases by Targeting Different Residues

et al. 2021

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“…Some algae species, including Ptychodiscus brevis , produce BTX-2 (brevetoxin B) which results in neurotoxic shellfish poisoning (NSP) by consuming BTX-2 contaminated shellfish [ 157 , 158 ]. To detect brevetoxin B (BTX-2) in seafood, Tang et al devised a practicable and straightforward magneto-controlled immunosensing platform.…”

Section: Food Toxicant Analyses Of 2d Nanomaterial-based Electrochmentioning

confidence: 99%

Development of Two-Dimensional Nanomaterials Based Electrochemical Biosensors on Enhancing the Analysis of Food Toxicants

Raja

Vedhanayagam

Preeth

et al. 2021

IJMS

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In recent times, food safety has become a topic of debate as the foodborne diseases triggered by chemical and biological contaminants affect human health and the food industry’s profits. Though conventional analytical instrumentation-based food sensors are available, the consumers did not appreciate them because of the drawbacks of complexity, greater number of analysis steps, expensive enzymes, and lack of portability. Hence, designing easy-to-use tests for the rapid analysis of food contaminants has become essential in the food industry. Under this context, electrochemical biosensors have received attention among researchers as they bear the advantages of operational simplicity, portability, stability, easy miniaturization, and low cost. Two-dimensional (2D) nanomaterials have a larger surface area to volume compared to other dimensional nanomaterials. Hence, researchers nowadays are inclined to develop 2D nanomaterials-based electrochemical biosensors to significantly improve the sensor’s sensitivity, selectivity, and reproducibility while measuring the food toxicants. In the present review, we compile the contribution of 2D nanomaterials in electrochemical biosensors to test the food toxicants and discuss the future directions in the field. Further, we describe the types of food toxicity, methodologies quantifying food analytes, how the electrochemical food sensor works, and the general biomedical properties of 2D nanomaterials.

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Brevetoxin (PbTx-2) influences the redox status and NPQ of Karenia brevis by way of thioredoxin reductase

Cited by 11 publications

References 67 publications

A Global Approach to Estimating the Abundance and Duplication of Polyketide Synthase Domains in Dinoflagellates

A Global Approach to Estimating the Abundance and Duplication of Polyketide Synthase Domains in Dinoflagellates

The Marine Neurotoxin Brevetoxin (PbTx-2) Inhibits Karenia brevis and Mammalian Thioredoxin Reductases by Targeting Different Residues

Development of Two-Dimensional Nanomaterials Based Electrochemical Biosensors on Enhancing the Analysis of Food Toxicants

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