Phylogenetic Analysis of Brachidinium Capitatum (Dinophyceae) From the Gulf of Mexico Indicates Membership in the Kareniaceae1

Henrichs, Darren W.; Sosik, Heidi M.; Olson, Robert J.; Campbell, Lisa

doi:10.1111/j.1529-8817.2011.00960.x

Cited by 24 publications

(15 citation statements)

References 28 publications

(43 reference statements)

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“…The CSA for each image was obtained by summing the number of image pixels remaining after removing the background pixels surrounding the cell (28). Images of dividing cells were removed from the data set before analyses of CSA.…”

Section: Methodsmentioning

confidence: 99%

Osmotic stress triggers toxin production by the dinoflagellate Karenia brevis

Errera¹,

Campbell

2011

Proc. Natl. Acad. Sci. U.S.A.

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With the increase in frequency of harmful algal blooms (HABs) worldwide, a better understanding of the mechanisms that influence toxin production is needed. Karenia brevis , the major HAB dinoflagellate in the Gulf of Mexico, produces potent neurotoxins, known as brevetoxins. Human health is directly impacted by blooms of K. brevis through consumption of shellfish contaminated by accumulated brevetoxins (neurotoxic shellfish poisoning) or from aerosolized brevetoxins in sea spray (reduced respiratory function); however, the reason for brevetoxin production has remained a mystery. Here we show that brevetoxin production increased dramatically in response to osmotic stress in three of the four K. brevis clones examined. By rapidly changing salinity to simulate a shift from oceanic conditions to a decreased salinity typical of coastal conditions, brevetoxin production was triggered. As a result, brevetoxin cell quota increased by >14-fold, while growth rate remained unchanged. Live images of K. brevis cells were also examined to assess changes in cell volume. In the K. brevis Wilson clone, cells responded quickly to hypoosmotic stress by increasing their brevetoxin cell quota from ∼10 to 160 pg of brevetoxin per cell, while cell volume remained stable. In contrast, the K. brevis SP1 clone, which has a consistently low brevetoxin cell quota (<1 pg per cell), was unable to balance the hypoosmotic stress, and although brevetoxin production remained low, average cell volume increased. Our findings close a critical gap in knowledge regarding mechanisms for toxin production in K. brevis by providing an explanation for toxin production in this harmful dinoflagellate.

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Section: Methodsmentioning

confidence: 99%

Osmotic stress triggers toxin production by the dinoflagellate Karenia brevis

Errera¹,

Campbell

2011

Proc. Natl. Acad. Sci. U.S.A.

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“…However, the following amendments are used: “core” dinoflagellates for dinokaryota [58], family Kareniaceae [17], [59], the inclusion of Brachidinium in Kareniaceae [60], genus Thoracosphaera [61], genus Adenoides [62], Biecheleria baltica (syn. Woloszynskia halophila ) [63], Pelagodinium beii (syn.…”

Section: Methodsmentioning

confidence: 99%

When Naked Became Armored: An Eight-Gene Phylogeny Reveals Monophyletic Origin of Theca in Dinoflagellates

et al. 2012

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The dinoflagellates are a diverse lineage of microbial eukaryotes. Dinoflagellate monophyly and their position within the group Alveolata are well established. However, phylogenetic relationships between dinoflagellate orders remain unresolved. To date, only a limited number of dinoflagellate studies have used a broad taxon sample with more than two concatenated markers. This lack of resolution makes it difficult to determine the evolution of major phenotypic characters such as morphological features or toxin production e.g. saxitoxin. Here we present an improved dinoflagellate phylogeny, based on eight genes, with the broadest taxon sampling to date. Fifty-five sequences for eight phylogenetic markers from nuclear and mitochondrial regions were amplified from 13 species, four orders, and concatenated phylogenetic inferences were conducted with orthologous sequences. Phylogenetic resolution is increased with addition of support for the deepest branches, though can be improved yet further. We show for the first time that the characteristic dinoflagellate thecal plates, cellulosic material that is present within the sub-cuticular alveoli, appears to have had a single origin. In addition, the monophyly of most dinoflagellate orders is confirmed: the Dinophysiales, the Gonyaulacales, the Prorocentrales, the Suessiales, and the Syndiniales. Our improved phylogeny, along with results of PCR to detect the sxtA gene in various lineages, allows us to suggest that this gene was probably acquired separately in Gymnodinium and the common ancestor of Alexandrium and Pyrodinium and subsequently lost in some descendent species of Alexandrium.

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“…The remaining three ribosomal regions and cox 1 gene were amplified using previously designed primers (see Henrichs et al. ).…”

Section: Methodsmentioning

confidence: 99%

“…DNA amplification and sequencing. Amplifications and sequencing of the SSU, ITS, and LSU regions of the ribosome and mitochondrial cob and cox1 genes were achieved following the method of Henrichs et al (2011). Primers amplifying the mitochondrial cob gene were Dinocob1F and Dinocob1R from Zhang et al (2005).…”

Section: Methodsmentioning

confidence: 99%

Morphology and Phylogeny of Prorocentrum texanum sp. nov. (Dinophyceae): A New Toxic Dinoflagellate from the Gulf of Mexico Coastal Waters Exhibiting Two Distinct Morphologies

Henrichs

Scott

Steidinger

et al. 2013

Journal of Phycology

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A new planktonic species of Prorocentrum is described from the Gulf of Mexico. First observed with the Imaging FlowCytobot, Prorocentrum texanum sp. nov. was characterized using LM, SEM, and TEM along with sequencing of the SSU, LSU, and ITS ribosomal regions and the mitochondrial cob and cox1 regions. P. texanum sp. nov. is a round to oval bivalvate dinoflagellate, with a prominent anterior, serrated solid flange on periflagellar a platelet and an opposing short, flat flange on the h platelet. The periflagellar area consists of 10 platelets. Both left and right valves have shallow round depressions and two-sized valve pores. The anterior ejectosome pore pattern differs between the left and right valve in relation to the periflagellar area and margins. Ten to eleven rows of tangential ejectosome pores are present on each valve. P. texanum sp. nov. has two varieties which exhibit distinct morphotypes, one round to oval (var. texanum) and the other pointed (var. cuspidatum). P. texanum var. cuspidatum is morphologically similar to P. micans in surface markings, but is smaller, and has a serrated periflagellar flange, and is genetically distinct from P. micans. Cytologically, P. texanum has two parietal chlo-roplasts, each with a compound, interlamellar pyrenoid, trichocysts, fibrous vesicles that resemble mucocysts, pusules, V- to U-shaped posterior nucleus, golgi, and tubular mitochondria. No genetic difference was found between the two varieties in the five genes examined. Phylogenetic analysis of the SSU, LSU, and ITS ribosomal regions place P. texanum sp. nov. as a sister group to P. micans. One isolate of P. texanum var. texanum produces okadaic acid.

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Phylogenetic Analysis of Brachidinium Capitatum (Dinophyceae) From the Gulf of Mexico Indicates Membership in the Kareniaceae1

Cited by 24 publications

References 28 publications

Osmotic stress triggers toxin production by the dinoflagellate Karenia brevis

Osmotic stress triggers toxin production by the dinoflagellate Karenia brevis

When Naked Became Armored: An Eight-Gene Phylogeny Reveals Monophyletic Origin of Theca in Dinoflagellates

Morphology and Phylogeny of Prorocentrum texanum sp. nov. (Dinophyceae): A New Toxic Dinoflagellate from the Gulf of Mexico Coastal Waters Exhibiting Two Distinct Morphologies

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