lar rapid increase in known analogues
has been observed for the azaspiracid
(AZA) group, with the first analogue
described in 1998 [64] and a review in
2014 reporting 30 analogues [65]. Only
three years later, over 50 analogues are
known for this group, including novel
phosphate derivatives [66-71]. This discovery rate could have been even more
rapid if the causative organisms of AZAs
had been elucidated earlier. However,
the delay from the first poisoning report in 1995 [72] to the discovery of the
culprit organism [73] in this case was
likely due to: i) the initial misidentification of the heterotrophic dinoflagellate
Protoperidinium crassipes (a vector of
AZAs upon its feeding on Azadinium) as
the causative agent, and ii) the difficulties in identification of such a small organism (<15 μm) by optical microscopy
in water samples fixed with acidic Lugols solution, the most common way to
preserve samples in routine plankton
monitoring.
Another phenomenon that has appeared repeatedly over the past 25
years is the discovery of slightly modified base skeletons for toxin groups.
The ciguatoxin (CTX) or CTX1B (= PCTX-1B) had been reported relatively
early on and had been isolated from
the moray eel [74]. The algal precursor CTX4A was only described in 1997
[75], yet a slightly modified base skeleton had been reported a few years
earlier from Gambierdiscus, i.e. CTX3C
[76]. Prymnesins are another example
of such skeleton variation which is indeed very labour-intensive in natural
product discovery as basically the full
discovery pipeline has to be completed:
bioguided fractionation and isolation of
the compound, purification and structural characterisation including mass
spectrometry, nuclear magnetic resonance (NMR), UV, infrared and potentially many other studies [77-78].
Finally, it should be noted that only a
few compound groups discovered since
1992 have been clearly related to human health issues. These include AZAs
(diarrhoea), ovatoxins and to a lesser
extent the toxins of Karenia brevisulcata
(aerosol and direct contact exposure).
There is a significant increase of
compounds that appear related to
fish kills, e.g. karlotoxins, karmitoxins,
prymnesins (A, B and C-Type) and K.
brevisulcata toxins. The need to clarify
16
the agents involved in fish kills has also
been highlighted by a recent systematic
review of toxic and harmful algae [109],
as well as by the Intergovernmental
Oceanographic Commission of UNESCO (IOC) Intergovernmental Panel
on Harmful Algal Blooms (IOC-IPHAB),
that included the topic in its list of Task
Teams.
The systematic inventory of toxins
has also been updated [78-108] by the
IOC-IPHAB Task Team on Biotoxins,
Management and Regulation over the
past few years and international databases, e.g. the Harmful Algal Event Database (HAEDAT) updated accordingly.
This same panel also contributes to
other IPHAB activities whenever chemical expertise is required (e.g. fish kills,
HABs and desalination etc.).
Drivers of change in management and regulation
There have been many drivers of change
in management practises (e.g. detection
methodology) and regulation. These
include (i) increased awareness by governments of poisoning events and fish
and shellfish mortalities through IPHAB
communication with member states (ii)
increased pressure from shellfish industry against the MBA for lipophilic toxins
due to its qualitative character, false
positive results and delays in reporting
(iii) technological advances. The conflicts caused by the disadvantages of the
animal assays (mouse and rat) for lipophilic toxins has been subject to much
debate [110] and decade-long efforts to
produce the necessary standards and
reference materials for the validation of
alternative methods, which have been
aided by researchers in Canada (e.g.
Michael Quilliam), Ireland, Japan (e.g.
Takeshi Yasumoto), New Zealand and
many other countries [111-122]. Again
the IPHAB panel played a pivotal role in
pushing this issue at European and international levels for several years with
the help of Phil Busby (New Zealand
Food Safety Authority), a long battle for
which the international community will
remember him.
Monitoring systems, management
practises and legislative changes have
been recently reviewed for different
trade blocks [123-125]. A major step
has been made with the switch from the
mouse bioassay to chemical testing by
LC-MS/MS for lipophilic toxins, first in
New Zealand, then Europe [126] and
most recently Japan.
Outlook
Several points can be raised looking
foreward from the historic perspective. Climate change is one of the most
striking challenges that has been raised
with regards to prediction of harmful
algal blooms (HABs), and while certain
trends appear to manifest themselves
[127], much more research is needed
to fully anticipate the impacts of climate change on our ecosystems, HABs
and their impacts on society [128]. As
mentioned above, the need to improve
our understanding of the impacts of micro-algae on other aquatic organisms,
in particular those that serve as major
food resources, i.e. fish and shellfish,
has been recognised and requires major
international efforts. The multiplicity of
compounds in the marine environment
only emerges with the recent onset of
the omics and while recent studies have
shown the feasibility to explore this
chemical diversity in the marine environment with techniques such as metabolomics [129-131], more systematic
studies will be required to effectively
monitor our coastal waters to protect
our resources and consumers. Finally, it
should be noted that one of the longestknown groups of toxin, i.e. the ciguatoxins, still continue to cause the highest
number of seafood poisoning globally
[132] and thus deserves the attention of
the scientific community over the next
few decades.
References:
1. http://hab.ioc-unesco.org/index.
php?option=com_content&view=article&
id=42&Itemid=0
2. http://www.phycotox.fr/decouvrir/
chimie/toxines-d-algues-et-classification.
html?lng=en
Author
Philipp Hess, Chair of IPHAB Task Team on
Biotoxins, Management and Regulation,
IFREMER, Phycotoxins Laboratory, Unit
DYNECO, Centre de Brest, BP 70, 29280
Plouzané, France
Email: philipp.hess@ifremer.fr
HARMFUL ALGAE NEWS NO. 59 / 2018
Harmful Algae News An IOC Newsletter on Toxic Algae and Algal Blooms No. 59 - February 2018 www.ioc-unesco.org/hab Content 25 years of HAN and IPHAB...... 1 25 YEARS Harmful Algae News was first published in early 1992 in response to requests from the participants at a number of IOC meetings and
pacted by harmful algal events. Since Harmful Algae News turned 20 years old in 2012, it has been a web based e-newsletter which meant longer issues were possible and back issues easily accessible. We are currently working on a searchable index for all Harmful Algae News issues. The start of Harmful
Intergovernmental Panel on Harmful Algal Blooms also turned 25! During 1992, the same Year as the IOC published the first issue of Harmful Algal News, it also established an Intergovernmental Panel on Harmful Algal Blooms (IPHAB) which has met every second year since it was formed. The Panel is com
A retrospective look at the early days of HAB cyst research, and a look to the future On this occasion of the 25th anniversary of the publication of Harmful Algae News, several of us were asked to look backwards in time to some of the earlier days of HAB science. One area of study that has been a ma
dormant stages and that these stages might be associated with certain bottom sediments. This then brings up the question, if benthic resting stages of certain dinoflagellates actually seed coastal red tides, are there localized areas of accumulation, or what we could call seedbeds?..........The poss
day, we still do not know if there are other factors at work perhaps a density-dependent or quorum-sensing type of response, or even a response to the presence of grazers or parasites. Exploration of this response has long been limited by the constraints associated with laboratory cultures, but now
approach did not stand up to data at my study locations. I raise this issue in this narrative because I want to correct what I feel are unjustified recommendations that may prevent those working on cysts from obtaining the type of biological data that can advance our understanding of certain types o
number of cysts in subsurface layers unable to germinate or emerge, presumably due to lack of oxygen or to the tortuous pathway posed by sediment grains and detritus. Many might think that major storms and waves can erode significant layers of sediment and transport cysts long distances, but here ag
How do algal blooms kill finfish and how can we mitigate their impacts? Algal blooms, water discolorations and their association with fish kills have been recorded since historic times, such as the description in the Bible (1000 years BC) all the waters that were in the river were turned to blood. A
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emergency harvest operations. To prevent the buildup of histamines, fish should be kept alive as long as possible during harvesting. This can be achieved by diluting algal concentrations via airlift upwelling, or by targeted in-pen emergency application of clays [23] that mop up ichthyotoxins at cla
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Dinophyceae the authors intended the new genus to be described according to the botanical nomenclature. The lack of a Latin diagnosis therefore made it invalid. The confusion has actually still not been resolved, and the problem needs to be discussed and decided upon by the International Nomenclatur
geographically widespread species being able to form fertile offspring, while other populations of the same species are not. Molecular techniques have contributed very significantly to solving many taxonomic problems, but they have not resulted in the emergence of a finite species concept. We have t
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lar rapid increase in known analogues has been observed for the azaspiracid (AZA) group, with the first analogue described in 1998 [64] and a review in 2014 reporting 30 analogues [65]. Only three years later, over 50 analogues are known for this group, including novel phosphate derivatives [66-71].
Butterflies in Brazil Abstracts are not always reliable guides to authors intentions. They are not expected to reveal a great deal about the evidence to be deployed in support of the science, evidence that may not even exist before deadlines for writing abstracts! Nevertheless, as examples of a mino
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the SEASENSING (BIO2014-56024C2-2-R) project and the CERCA Programme/Generalitat de Catalunya. A. Tudó and A. Toldrà acknowledge IRTAURV-Banco Santander for their respective PhD grants (2016 PMF-PIPF-74 and 2015PMF-PIPF-67). The authors are grateful to Vanessa Castan and José Luis Costa for sampling
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The XVIII International Conference on Harmful Algae is approaching! It is time for nominations for achievement awards (Yasumoto Life Time and Patrick Gentien Young Scientist), registration to the conference as a student if you wish to participate in the Maureen Keller Award competition and fundraisi
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18th International Conference on Harmful Algae www.icha2018.com IMPORTANT DEADLINES Abstract submission deadline: 15 April 2018 Early bird registration: 15 July 2018 Get the 17 ICHA Proceedings at www.issha.org Eds-in-chief Beatriz Reguera, IEO, Vigo, Spain Eilen Bresnan, MARLAB, Scotland, UK Regi