Harmful Algal Species Fact Sheet: Amphidomataceae

AMPHIDOMATACEAE 04/16/2018 16:53:19 Page 575 16 Harmful Algal Species Fact Sheets 575 Amphidomataceae Figure 1 LM micrographs of Azadinium spinosum (a), Az. poporum (b), Az. dexteroporum (c) and Amphidoma languida (d). Scale bars = 2 μm. Figure 2 Global records of the four species of Amphidomataceae known to produce azaspiracids (AZA). Table 1 Members of Amphidomataceae and status as AZA producers. AZA producer no AZA found not analysed yet Azadinium spinosum Azadinium obesum Azadinium caudatum var. caudatum Azadinium poporum Azadinium polongum Azadinium luciferelloides Azadinium dexteroporum Azadinium caudatum var. margalefii Amphidoma nucula Amphidoma languida Azadinium dalianense Amphidoma acuminata Azadinium trinitatum Amphidoma curtata Azadinium cuneatum Amphidoma depressa Azadinium concinnum Amphidoma elongata Azadinium zhuanum Amphidoma laticincta Amphidoma parvula Amphidoma obtusa Amphidoma steinii AMPHIDOMATACEAE 04/16/2018 16:53:19 Page 576 576 Harmful Algal Blooms: A Compendium Desk Reference Amphidomataceae General: Azaspiraids (AZA) are a group of lipophilic by a cover plate. Plate details important for species polyether toxins first detected and described in the identification include the presence/absence and/or late 1990s. With the description of Azadinium spi location of a single antapical spine and primarily the nosum in 2009, the first source organism has been position of a ventral pore. Morphology, and in identified. Currently, there are four out of 22 species particular the plate tabulation with five different of the genera Azadinium and Amphidoma (merged rows of plates, undoubtedly classified the family in the family Amphidomataceae) that have been Amphidomataceae as a member of the dinophy shown to produce AZA. However, it has to be kept in cean subclass Peridiniphycidae (Tillmann et al., mind that there is only a limited number of cultured 2009). The relation to one of the two orders of the strains available, and it is thus not clear if and to what subclass (i.e. Gonyaulacales and Peridiniales), extent AZA production is a species-specific stable however, is less clear as some morphological traits phaenotypic trait. imply affinity to Peridinales and others to General Morphology: All AZA-producing species of Gonyaulacales. Using a concatenated alignment of Azadinium and Amphidoma languida are small LSU and SSU, the Amphidomataceae have been (size of about 10–16 μm) and ovoid to elliptical in placed on the peridinean branch remote from the shape with a hemispherical hyposome. In all these Gonyaulacales, but the true relation to Peridi fi species, the episome is larger than the hyposome, niales could not be identi ed reliably (Tillmann with slightly convex sides ending in a distinctly et al., 2014). It thus remains to be determined pointed apex. The cingulum is deep and wide, whether they are part of the Peridiniales or rep accounting for roughly 1/5 to 1/4 of the cell length. resent a distinct lineage that would deserve the A central or more posteriorly located large nucleus recognition at a higher taxonomic level. is visible, which generally is round to elliptical but Known Distribution: Although the first species of maybecomedistinctlyelongatedinshapecloseto Azadinium were initially described from the North cell division. All species are photosynthetic and Sea, there is increasing evidence that AZA-pro possess a presumably single chloroplast, which is ducing species have a wide geographical distribu parietally arranged, lobed, and normally extends tion. Nevertheless, knowledge on the biogeography into both the epi- and hyposome. For all of the of the genus or of certain species currently is rather AZA-producing species, stalked pyrenoid(s) are limited and patchy. It is based on the troublesome visibleinthelightmicroscopebecauseofadistinct procedure of isolating, cultivating and fully char starch cup. Azadinium spp. and Amphidoma acterizing local strains; on a very few records of languida have delicate thecal plates difficult to species detected by scanning plankton samples by detect in light microscopy (LM), so that live electron microscopy; or on positive signals using cells are sometimes difficult to differentiate from species-specific molecular detection methods. small athecate gymnodinoid species. Plate pattern Cysts: Knowledge on the life cycle of Azadinium and/ and thecal plate details are important for deter or Amphidoma is quite incomplete. Successful iso mination of the genus and species, but require lation of Az. poporum by incubating sediment scanning electron microscopy (SEM). Species of samples (Potvin et al., 2012; Gu et al., 2013) made the Azadinium are characterised by the Kofoidean ´ ´´ ´´´ presence of cysts quite likely for that species, and that plate pattern of Po, cp, X, 3–4 ,2–3a, 6 , C6, 5S, 6 , fi ´´´´ has been con rmed by Gu et al. (2013): in one out of 2 , whereas Amphidoma languida has six apical 25 cultured strains, they observed the presence of a plates and no anterior intercalary plates. A very few distinct cysts. These cysts are ellipsoid, around characteristic feature among the AZA-relevant 15 μm long and 10 μm wide, and are filled with pale species is the prominent apical pore complex visible granules and a yellow accumulation body. Likewise, in LM, which is composed of an X-plate and a pore the species Az. polongum (a non-AZA producer) plate with a central round pore covered has been described to produce cysts in culture, Author: Urban Tillmann AMPHIDOMATACEAE 04/16/2018 16:53:20 Page 577 16 Harmful Algal Species Fact Sheets 577 Amphidomataceae round cells of 10–16 μm in diameter and with pale known yet. An increasing number of new AZA are white inclusion. No cyst-like cells have been discovered in the Amphidomatacean cultures. Initial reported for other species, including Az. spinosum, mass spectral data (Krock et al., 2012) as well as Az. dexteroporum and Am. languida. Clearly, more structural elucidation by nuclear magnetic reso data and observations are needed to clarify the whole nance (NMR) spectroscopy (Kilcoyne et al., 2014b; life cycle of Amphidomataceae. Krock et al., 2015) showed that some of the new fl Toxin: Species of Amphidomataceae are the source AZAdiscoveredindino agellates are structurally of azaspiracids (AZA), a class of polyether toxins unique from previously reported analogues by hav fi discovered almost 20 years ago. Azaspiracids are ing a modi cation of the nitrogen-containing I-ring polyketides with a highly hydroxylated carbon of the molecule, which consists of either a missing chain that is cyclised by ether bridges, and they methyl group at C39 or an additional double bond. contain a six-membered cyclic secondary amino All four described European strains of Az. spino ring. To date more than 50 AZA analogs are sum have the same toxin profile consisting of known. These include about 20 of dinoflagellate AZA-1, -2, and -33 (Tillmann et al., 2012b), and a origin, and the others are thought to be produced few minor compounds have additionally been by bioconversion in shellfish (Hess et al., 2014). found in the Scottish strain (Kilcoyne et al., Azaspiracids are known to be responsible for 2014b). For Az. poporum, a larger number of gastrointestinal disorders with the consumption of strains from different areas around the globe have AZA-contaminated shellfish, with symptoms been described, and this is reflected by a considera quite similar to those of DSP, such as nausea, ble diversity within this species in terms of toxin vomiting, diarrhea and stomach cramps. Prelim profiles. Whereas all three available North Sea inary studies of AZA suggested that these com strains produce AZA-37, Az. poporum from the pounds are highly toxic with multi-organ damage in Asiatic Pacific region produces more complex mice and teratogenic potential to developing fish, AZA profiles, including AZA-2, -11, -36, -40, -41 along with a wide array of cellular-level effects, in different combinations, and also strains without ranging from cytotoxicity to apoptosis and to effects any known AZA have been described. on the hERG potassium channel (reviewed by Twiner Azaspiracid-2 (AZA-2) is the major AZA produced et al., 2014). Minimal lethal doses (i.p. mice) for the by Az. poporum from Argentina and by a strain most dominant AZA in mussels have been deter from the Mediterranean, whereas strains from the μ mined as 200, 110, and 140 g/kg for AZA-1, -2, and Pacific coast of Chile produce AZA-11. Most -3, respectively (Satake et al., 1998; Ofuji et al., 1999). recently, the new AZA-59 was identified from Az. μ Consequently, a regulatory limit of 160 g/kg mussel poporum strains isolated from Puget Sound, WA meat for AZA-1 to AZA-3 was implemented in 2002 (Kim et al., 2017). A feature that is shared among into the EU biotoxin legislation. More recent studies some Asian Pacific and Argentinean strains of Az. yielded similar results for mouse toxicity for AZA-2 poporum is the production of minor amounts of and AZA-3, but a distinctly lower dose (higher tox AZA-related compounds with higher molecular μ icity) of 74 g/kg for AZA-1 (Kilcoyne et al., 2014a). masses. For the Argentinean strains, one of these Oral mouse studies indicated no additive or syner compounds has been identified as AZA-2 phos gistic effects when AZA was administered in com phate, which is the first report of a phosphated bination with okadaic acid or yessotoxin (Kilcoyne marine algal toxin (Tillmann et al., 2016). et al., 2014a). The presence of AZA has also been unambigu Around 20 AZA analogs are currently ously described for the Mediterranean strain of fl described to be of dino agellate origin. Among Az. dexteroporum (Percopo et al., 2013), and fi the dominant AZA found in shell sh, AZA-1 detailed LC-MS analysis confirmed the andAZA-2areproducedbyAzadinium, presense of six novel AZA and AZA-35 whereas no planktonic source of AZA-3 is (Rossi et al., 2017). A new strain of Az.

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