Fig. 2. Schematic drawing of the life cycle of the pennate diatom Pseudo-nitzschia multistriata. The vegetative phase is characterized by progressive cell size reduction of the population. When cells reach the sexual size threshold (SST), they can either keep decreasing in size until they die, or undergo sexual reproduction and escape the size-decreasing process producing large initial cells. The perception of chemical cues deriving from the mating partner brings cells of opposite mating type to pair and haploid gametes are produced following meiosis. Conjugation of gametes produces two expandable zygotes that develop into auxospores, within which an initial cell of maximum size is synthesized, restoring the vegetative phase of the cycle. Representative microscopic images of the different stages are shown outside the circle; bar, 10 μm. From [7]. diatoms selected for genome sequencing when this was still a demanding and time consuming effort. The P. multiseries genome has been publicly available since 2011 (https://mycocosm.jgi.doe. gov/Psemu1/Psemu1.home.html) and despite being quite fragmented, possibly due to the high content of repetitive sequences it has represented a valuable resource used to explore diatom biology in general and in many comparative genomic analyses. Subsequently, Pseudo-nitzschia transcriptomes became available through the Marine Microbial Eukaryotic Transcriptome Sequencing Project (MMETSP), enlarging the repertoire of sequence resources for the genus (https://www.imicrobe.us/#/ search/mmetsp). Currently, thanks to this initiative, transcriptomics data are available for P. arenysensis, P. delicatissima, P. fraudulenta, P. australis, P. heimii and P. pungens. Transcriptomics data have also been generated in dedicated studies for other species, namely P. multiseries, P. granii, P. seriata and P. obtusa [1-3]. 2 Here we illustrate genomic resources that are available to the research community for another toxic Pseudonitzschia species, P. multistriata. We also provide a few examples of questions that can be addressed by genomic approaches. Pseudo-nitzschia multistriata was described in 1993 by Hideaki Takano from coastal waters in southern Japan. The species produces domoic acid [4] and has been reported from various regions world-wide (Mediterranean Sea, Gulf of Mexico, Malaysia, Singapore, New Zealand, the Pacific coast of Mexico, see [5]). Cells of P. multistriata can easily be identified in light micros- copy due to their distinct sigmoid shape (Figure 1). This species began to be recorded at the Long Term Ecological Research station Mare Chiara in the Gulf of Naples in 1993 and since then is regularly recorded in summer-early autumn. The relative ease of identification made it a model for a long term study of population structure using microsatellites [6]. This study required the isolation of a few hundred strains to obtain their DNA. Availability of all of these strains represented a great resource facilitating the use of P. multistriata as a genetic model, allowing genetic crosses and production of new generations in the laboratory. We would like to avail of this opportunity to publicize our request for P. multistriata strains to all of our colleagues working with phytoplankton samples who may find the species, easily distinguishable from other Pseudo-nitzschia due to the curved tips and sigmoid shape. Strains from different geographic locations will greatly enrich ongoing population genomics analyses and could reveal more about core and dispensable regions of the genome, selection, and ultimately about the evolution of this toxic species. HARMFUL ALGAE NEWS NO. 65 / 2020 Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 65 - September 2020 www.ioc-unesco.org/hab Genomic resources for the domoic acid-producing diatom Pseudo-nitzschia multistriata Species responsible for Harmful Algal Blooms (HABs) are among the best studied unicellular microa Fig. 2. Schematic drawing of the life cycle of the pennate diatom Pseudo-nitzschia multistriata. The vegetative phase is characterized by progressive cell size reduction of the population. When cells reach the sexual size threshold (SST), they can either keep decreasing in size until they die, or un Fig. 3. The genome browser available on the SZN BioInforma platform. The genome could be sequenced exploiting inbred strains, obtained from the cross of a first generation of sibling strains [7]. Because of the lower polymorphism of inbreds, it was possible to reconstruct long fragments of DNA from When tides collide: Harmful cyanobacterial and microalgal blooms in Florida and implications for risk assessment Cyanobacterial blooms are a regular occurrence in southern Florida. Water releases from Lake Okeechobee to maintain the water level in this large lake regularly occur along the St. Lucie Pim and Calusa Waterkeepers for assistance in sampling. References 1. Metcalf JS et al (in press). Neurotox Res 2. Matthiensen et al 2000. In: de Koe WJ et al (eds), Mycotoxins and Phycotoxins in Perspective at the Turn of the Millenium. Proc Xth Int IUPAC symposium on Mycotoxins and Phycotoxins, Gu Record levels of Dinophysistoxin-2 in clams from Douarnenez Bay, France, after an unusual bloom of Dinophysis acuta Fig. 1. Location of Douarnenez Bay (48 5 29 North; 4 19 51 West), Western French Atlantic coast. The official monitoring network for phytoplankton and algal toxins in French shellfis Fig. 4. Weekly lipophilic toxin concentrations in Donax spp. in 2019 and 2020. Fig. 3. (A) Percentage of Dinophysis species in Douarnenez Bay water samples between 2010 and August 2020. (B) Mean percentage of DSP toxins in Douarnenez Bay in Donax spp. between 2010 and August 2020. recorded in Dona New insights on the diversity of the dinoflagellate genus Ostreopsis in lagoons of French Polynesia, South Pacific Ocean French Polynesia is a vast territory in the South Pacific Ocean, stretching over an expanse of more than 1,200 miles with a surface area as large as Europe. It is composed of 118 health hazards posed by the proliferation of this species in French Polynesian lagoons. Future studies should aim at developing a better understanding the biogeographic distribution of this species, as well as assessing the impacts of its associated toxins on coral reef ecosystems and/or putative ac Toxin profiles of Gambierdiscus lapillus from the Cook Islands Species of the dinoflagellate genus Gambierdiscus produce the toxins responsible for ciguatera fish poisoning (CFP), an illness that has been prevalent throughout the Pacific and particularly in the Cook Islands [1]. The illness is cause Fig. 3. Phylogenetic analysis of partial large subunit ribosomal DNA sequences (D8D10 region) from the Gambierdiscus strains isolated in this study (in bold font) using Bayesian analyses. Values at nodes represent Bayesian posterior probability support. Scale bar is substitutions per site. lus was Unusual bloom of the red alga Ceramium sp. (Ceramiales, Rhodophyta) in Cartagena, Colombia, SW Caribbean Sea Fig. 1. Map of the study site. Macroalgal blooms are frequently associated with eutrophication of coastal waters [1]. These blooms are mainly composed of ephemeral and opportunistic green a ported as bloom forming species, and this finding adds another genus to the group of harmful bloom-forming macroalgae. Furthermore, this report highlights the potential introduction of a new species which has passed undetected until now. This would not be the first case of a potentially introduced b Distribution of the fish-killing dinoflagellate Karlodinium (Dinophyceae) in the Johor Strait, Malaysia Fig. 1. Sampling sites in the Johor Strait Species of Karlodinium are naked dinoflagellates. More than one third of the named species have been known to cause fish mortality. Toxigenic Karlod- Bloom of a red tide species Akashiwo sanguinea in Semerak Lagoon, Kelantan, Malaysia March 2016: i.e. Pseudo-nitzschia spp. (potentially toxic species), Chaetoceros, Skeletonema, and Blixaea quinquecornis (red tides, fish kills) [3]. In this survey, we confirmed the blooming species as the dinoflag Fig. 3 Bayesian trees of Akashiwo sanguinea inferred from (A) LSU rDNA and (B) ITS datasets. Values on nodes represent bootstrap supports of MP, ML, and posterior probabilities of BI Continued from page 14 sulcus extension invading the epicone is visible (Fig. 3B). Cells are slightly pigmented, wi CLEFSA project identifies Harmful Algal Blooms as a threat to food safety resulting from climate change Fig. 1. Organizations involved in the CLEFSA project Climate change is one of the key drivers of emerging risks for food and feed safety, plant and animal health (including terrestrial and aquat Fig. 3. CLEFSA Multi-Criteria strategy which several directly related to toxins produced by harmful algal blooms (HABs). These include: ciguatoxin, domoic acid, okadaic acid, saxitoxin, pinnatoxin, tetrodotoxin, beta-methylamino-L-alanine (BMAA) and palytoxin analogues. The analysis indicates that Blooming Buddies: MSc Research Projects Extend our Knowledge on Bloom-Forming Freshwater Cyanobacteria Freshwater cyanobacteria blooms are an increasing problem globally and much work is focussing on understanding bloom dynamics and toxin production in order to better manage the inherent health risk Fig. 2. Confocal microscopy images of Planktothrix sp. CAWBG59 (A), Microcystis aeruginosa CAWBG617 (B) and Nodularia spumigena CAWBG21 (C) stained with SYTOXTM green so that lysed cells fluoresce green, whilst intact cells are detected by red chlorophyll autofluorescence. bacterium interfering wit 25 years of service enhancing the capacity to monitor and manage HABs Fig. 1. Participants from the first course held at the IOC Centre in Copenhagen in 1995 The IOC Science and Communication Centre on Harmful Algae opened in May 1995 at the University of Copenhagen, Denmark. It was a new concept International Phytoplankton Intercomparison (IPI) exercise in abundance and composition of marine microalgae Dear participants of the annual IPI (International Phytoplankton Intercomparison) exercise in abundance and composition of marine microalgae: This note is to confirm that due to the ongoing p Canadian review: Marine harmful algal blooms and phycotoxins of concern to Canada As has been reinforced all too well in recent months with the COVID-19 pandemic, the world is indeed interconnected. The international harmful algal bloom community recognized this early on, with a series of internatio Fig. 2. Maps showing the location of selected phycotoxins on the Canadian east (left) and west (right) coast. Symbols represent domoic acid and okadaic acid group toxins above (closed symbols) and below (open symbols) the regulatory action level. The green shaded areas show the distribution of saxit Terri Wells (DFO-NAFC, St. Johns, NL); Michel Poulin (Canadian Museum of Nature, Ottawa, ON); Wade A. Rourke (CFIA, Dartmouth, NS). Fig. 4. Heterosigma akashiwo bloom in Kyuquot, British Columbia, 1996 (Photo courtesy of Nicky Haigh, Microthalassia Consultants Inc., Nanaimo, BC) References 1. LoCi ISSHAs Corner CHA 2021 Hybrid Conference, NEW DATE!! Dear ISSHA members and colleagues: Due to the COVID-19 pandemic and following recommendations of the World Health Organization and National Health Authorities, the 19th International Conference on Harmful Algae has been postponed to October 10-15 HAN Subscription To subscribe to Harmful Algae News anyone can send a mail to sympa@sympa. iode.org with the subject subscribe han do not write any text at all in the mail message itself. The system will send back a mail to you with subject similar to auth 22d6dcd9 subscribe han and with instructio