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Dr. Panagiota Katikou
Ministry of Rural Development and Food

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0 marine biotoxins
0 phycotoxins
0 harmful algal blooms
0 toxic pufferfish
0 emerging marine toxins

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mouse bioassay
tetrodotoxins
marine biotoxins
liquid chromatography mass spectrometry
lipophilic toxins

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Review
Published: 26 April 2019 in Toxins
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Tetrodotoxin (TTX) and its analogues are naturally occurring toxins responsible worldwide for human intoxication cases and fatalities, mainly associated with pufferfish consumption. In the last decade, TTXs were detected in marine bivalves and gastropods from European waters. As TTXs are not regulated or monitored at EU level, their unexpected occurrence in shellfish raised concerns as a food safety hazard and revealed the necessity of a thorough assessment on the public health risks associated with their presence. For this reason, the European Food Safety Authority (EFSA) was requested by the European Commission to provide a scientific opinion, finally adopted in March 2017, according to which a provisional concentration below 44 μg TTX equivalents/kg shellfish meat, based on a large portion size of 400 g, was considered not to result in adverse effects in humans. The EFSA expert panel, however, recognized a number of shortcomings and uncertainties related to the unavailability of sufficient scientific data and provided relevant recommendations for future research to overcome these data gaps identified in order to further refine the risk assessment on TTXs. The present review aims to summarize the knowledge obtained towards addressing these recommendations in the two years following publication of the EFSA opinion, at the same time highlighting the points requiring further investigation.

ACS Style

Panagiota Katikou. Public Health Risks Associated with Tetrodotoxin and Its Analogues in European Waters: Recent Advances after The EFSA Scientific Opinion. Toxins 2019, 11, 240 .

AMA Style

Panagiota Katikou. Public Health Risks Associated with Tetrodotoxin and Its Analogues in European Waters: Recent Advances after The EFSA Scientific Opinion. Toxins. 2019; 11 (5):240.

Chicago/Turabian Style

Panagiota Katikou. 2019. "Public Health Risks Associated with Tetrodotoxin and Its Analogues in European Waters: Recent Advances after The EFSA Scientific Opinion." Toxins 11, no. 5: 240.

Journal article
Published: 01 December 2017 in Sensors and Actuators B: Chemical
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ACS Style

Laia Reverté; Mònica Campàs; Betsy Jean Yakes; Jonathan R. Deeds; Panagiota Katikou; Kentaro Kawatsu; Michael Lochhead; Christopher T. Elliott; Katrina Campbell. Tetrodotoxin detection in puffer fish by a sensitive planar waveguide immunosensor. Sensors and Actuators B: Chemical 2017, 253, 967 -976.

AMA Style

Laia Reverté, Mònica Campàs, Betsy Jean Yakes, Jonathan R. Deeds, Panagiota Katikou, Kentaro Kawatsu, Michael Lochhead, Christopher T. Elliott, Katrina Campbell. Tetrodotoxin detection in puffer fish by a sensitive planar waveguide immunosensor. Sensors and Actuators B: Chemical. 2017; 253 ():967-976.

Chicago/Turabian Style

Laia Reverté; Mònica Campàs; Betsy Jean Yakes; Jonathan R. Deeds; Panagiota Katikou; Kentaro Kawatsu; Michael Lochhead; Christopher T. Elliott; Katrina Campbell. 2017. "Tetrodotoxin detection in puffer fish by a sensitive planar waveguide immunosensor." Sensors and Actuators B: Chemical 253, no. : 967-976.

Journal article
Published: 01 December 2017 in Current Opinion in Food Science
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Panagiota Katikou; Aristidis Vlamis. Tetrodotoxins: recent advances in analysis methods and prevalence in European waters. Current Opinion in Food Science 2017, 18, 1 -6.

AMA Style

Panagiota Katikou, Aristidis Vlamis. Tetrodotoxins: recent advances in analysis methods and prevalence in European waters. Current Opinion in Food Science. 2017; 18 ():1-6.

Chicago/Turabian Style

Panagiota Katikou; Aristidis Vlamis. 2017. "Tetrodotoxins: recent advances in analysis methods and prevalence in European waters." Current Opinion in Food Science 18, no. : 1-6.

Journal article
Published: 20 January 2017 in Scientific Reports
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In 2012, Tetrodotoxin (TTX) was identified in mussels and linked to the presence of Prorocentrum minimum (P. minimum) in Greece. The connexion between TTX and P. minimum was further studied in this paper. First, the presence of TTX-producer bacteria, Vibrio and Pseudomonas spp, was confirmed in Greek mussels. In addition these samples showed high activity as inhibitors of sodium currents (INa). P. minimum was before associated with neurotoxic symptoms, however, the nature and structure of toxins produced by this dinoflagellate remains unknown. Three P. minimum strains, ccmp1529, ccmp2811 and ccmp2956, growing in different conditions of temperature, salinity and light were used to study the production of toxic compounds. Electrophysiological assays showed no effect of ccmp2811 strain on INa, while ccmp1529 and ccmp2956 strains were able to significantly reduce INa in the same way as TTX. In these samples two new compounds, m/z 265 and m/z 308, were identified and characterized by liquid chromatography tandem high-resolution mass spectrometry. Besides, two TTX-related bacteria, Roseobacter and Vibrio sp, were observed. These results show for the first time that P. minimum produce TTX-like compounds with a similar ion pattern and C9-base to TTX analogues and with the same effect on INa.

ACS Style

Inés Rodríguez; Amparo Alfonso; Eva Alonso; Juan A. Rubiolo; María Roel; Aristidis Vlamis; Panagiota Katikou; Stephen A. Jackson; Margassery Lekha Menon; Alan Dobson; Luis M. Botana. The association of bacterial C9-based TTX-like compounds with Prorocentrum minimum opens new uncertainties about shellfish seafood safety. Scientific Reports 2017, 7, srep40880 .

AMA Style

Inés Rodríguez, Amparo Alfonso, Eva Alonso, Juan A. Rubiolo, María Roel, Aristidis Vlamis, Panagiota Katikou, Stephen A. Jackson, Margassery Lekha Menon, Alan Dobson, Luis M. Botana. The association of bacterial C9-based TTX-like compounds with Prorocentrum minimum opens new uncertainties about shellfish seafood safety. Scientific Reports. 2017; 7 (1):srep40880.

Chicago/Turabian Style

Inés Rodríguez; Amparo Alfonso; Eva Alonso; Juan A. Rubiolo; María Roel; Aristidis Vlamis; Panagiota Katikou; Stephen A. Jackson; Margassery Lekha Menon; Alan Dobson; Luis M. Botana. 2017. "The association of bacterial C9-based TTX-like compounds with Prorocentrum minimum opens new uncertainties about shellfish seafood safety." Scientific Reports 7, no. 1: srep40880.

Correction
Published: 03 February 2016 in Analytical Chemistry
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ACS Style

Laia Reverté; Pablo De La Iglesia; Vanessa Del Río; Katrina Campbell; Christopher T. Elliott; Kentaro Kawatsu; Panagiota Katikou; Jorge Diogène; Mònica Campàs. Correction to Detection of Tetrodotoxins in Puffer Fish by a Self-Assembled Monolayer-Based Immunoassay and Comparison with Surface Plasmon Resonance, LC-MS/MS, and Mouse Bioassay. Analytical Chemistry 2016, 88, 2511 -2511.

AMA Style

Laia Reverté, Pablo De La Iglesia, Vanessa Del Río, Katrina Campbell, Christopher T. Elliott, Kentaro Kawatsu, Panagiota Katikou, Jorge Diogène, Mònica Campàs. Correction to Detection of Tetrodotoxins in Puffer Fish by a Self-Assembled Monolayer-Based Immunoassay and Comparison with Surface Plasmon Resonance, LC-MS/MS, and Mouse Bioassay. Analytical Chemistry. 2016; 88 (4):2511-2511.

Chicago/Turabian Style

Laia Reverté; Pablo De La Iglesia; Vanessa Del Río; Katrina Campbell; Christopher T. Elliott; Kentaro Kawatsu; Panagiota Katikou; Jorge Diogène; Mònica Campàs. 2016. "Correction to Detection of Tetrodotoxins in Puffer Fish by a Self-Assembled Monolayer-Based Immunoassay and Comparison with Surface Plasmon Resonance, LC-MS/MS, and Mouse Bioassay." Analytical Chemistry 88, no. 4: 2511-2511.

Comparative study
Published: 02 July 2015 in Analytical Chemistry
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The increasing occurrence of puffer fish containing tetrodotoxin (TTX) in the Mediterranean could represent a major food safety risk for European consumers and threaten the fishing industry. The work presented herein describes the development of a new enzyme linked immunosorbent assay (mELISA) based on the immobilization of TTX through dithiol monolayers self-assembled on maleimide plates, which provides an ordered and oriented antigen immobilization and favors the antigen-antibody affinity interaction. The mELISA was found to have a limit of detection (LOD) of TTX of 0.23 mg/kg of puffer fish matrix. The mELISA and a surface plasmon resonance (SPR) immunosensor previously developed were employed to establish the cross-reactivity factors (CRFs) of 5,6,11-trideoxy-TTX, 5,11-deoxy-TTX, 11-nor-TTX-6-ol, and 5,6,11-trideoxy-4-anhydro-TTX, as well as to determine TTX equivalent contents in puffer fish samples. Results obtained by both immunochemical tools were correlated (R(2) = 0.977). The puffer fish samples were also analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and the corresponding CRFs were applied to the individual TTX contents. Results provided by the immunochemical tools, when compared with those obtained by LC-MS/MS, showed a good degree of correlation (R(2) = 0.991 and 0.979 for mELISA and SPR, respectively). The mouse bioassay (MBA) slightly overestimated the CRF adjusted TTX content of samples when compared with the data obtained from the other techniques. The mELISA has been demonstrated to be fit for the purpose for screening samples in monitoring programs and in research activities.

ACS Style

Laia Reverté; Pablo De La Iglesia; Vanessa Del Río; Katrina Campbell; Christopher T. Elliott; Kentaro Kawatsu; Panagiota Katikou; Jorge Diogène; Mònica Campàs. Detection of Tetrodotoxins in Puffer Fish by a Self-Assembled Monolayer-Based Immunoassay and Comparison with Surface Plasmon Resonance, LC-MS/MS, and Mouse Bioassay. Analytical Chemistry 2015, 87, 10839 -10847.

AMA Style

Laia Reverté, Pablo De La Iglesia, Vanessa Del Río, Katrina Campbell, Christopher T. Elliott, Kentaro Kawatsu, Panagiota Katikou, Jorge Diogène, Mònica Campàs. Detection of Tetrodotoxins in Puffer Fish by a Self-Assembled Monolayer-Based Immunoassay and Comparison with Surface Plasmon Resonance, LC-MS/MS, and Mouse Bioassay. Analytical Chemistry. 2015; 87 (21):10839-10847.

Chicago/Turabian Style

Laia Reverté; Pablo De La Iglesia; Vanessa Del Río; Katrina Campbell; Christopher T. Elliott; Kentaro Kawatsu; Panagiota Katikou; Jorge Diogène; Mònica Campàs. 2015. "Detection of Tetrodotoxins in Puffer Fish by a Self-Assembled Monolayer-Based Immunoassay and Comparison with Surface Plasmon Resonance, LC-MS/MS, and Mouse Bioassay." Analytical Chemistry 87, no. 21: 10839-10847.

Journal article
Published: 20 May 2015 in Toxins
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During official shellfish control for the presence of marine biotoxins in Greece in year 2012, a series of unexplained positive mouse bioassays (MBA) for lipophilic toxins with nervous symptomatology prior to mice death was observed in mussels from Vistonikos Bay–Lagos, Rodopi. This atypical toxicity coincided with (a) absence or low levels of regulated and some non-regulated toxins in mussels and (b) the simultaneous presence of the potentially toxic microalgal species Prorocentrum minimum at levels up to 1.89 × 103 cells/L in the area’s seawater. Further analyses by different MBA protocols indicated that the unknown toxin was hydrophilic, whereas UPLC-MS/MS analyses revealed the presence of tetrodotoxins (TTXs) at levels up to 222.9 μg/kg. Reviewing of official control data from previous years (2006–2012) identified a number of sample cases with atypical positive to asymptomatic negative MBAs for lipophilic toxins in different Greek production areas, coinciding with periods of P. minimum blooms. UPLC-MS/MS analysis of retained sub-samples from these cases revealed that TTXs were already present in Greek shellfish since 2006, in concentrations ranging between 61.0 and 194.7 μg/kg. To our knowledge, this is the earliest reported detection of TTXs in European bivalve shellfish, while it is also the first work to indicate a possible link between presence of the toxic dinoflagellate P. minimum in seawater and that of TTXs in bivalves. Confirmed presence of TTX, a very heat-stable toxin, in filter-feeding mollusks of the Mediterranean Sea, even at lower levels to those inducing symptomatology to humans, indicates that this emerging risk should be seriously taken into account by the EU to protect the health of shellfish consumers.

ACS Style

Aristidis Vlamis; Panagiota Katikou; Ines Rodriguez; Verónica Rey; Amparo Alfonso; Angelos Papazachariou; Thetis Zacharaki; Ana M. Botana; Luis M. Botana. First Detection of Tetrodotoxin in Greek Shellfish by UPLC-MS/MS Potentially Linked to the Presence of the Dinoflagellate Prorocentrum minimum. Toxins 2015, 7, 1779 -1807.

AMA Style

Aristidis Vlamis, Panagiota Katikou, Ines Rodriguez, Verónica Rey, Amparo Alfonso, Angelos Papazachariou, Thetis Zacharaki, Ana M. Botana, Luis M. Botana. First Detection of Tetrodotoxin in Greek Shellfish by UPLC-MS/MS Potentially Linked to the Presence of the Dinoflagellate Prorocentrum minimum. Toxins. 2015; 7 (5):1779-1807.

Chicago/Turabian Style

Aristidis Vlamis; Panagiota Katikou; Ines Rodriguez; Verónica Rey; Amparo Alfonso; Angelos Papazachariou; Thetis Zacharaki; Ana M. Botana; Luis M. Botana. 2015. "First Detection of Tetrodotoxin in Greek Shellfish by UPLC-MS/MS Potentially Linked to the Presence of the Dinoflagellate Prorocentrum minimum." Toxins 7, no. 5: 1779-1807.

Journal article
Published: 01 January 2014 in Plankton and Benthos Research
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Aristidis Vlamis; Panagiota Katikou. Climate influence on Dinophysis spp. spatial and temporal distributions in Greek coastal water. Plankton and Benthos Research 2014, 9, 15 -31.

AMA Style

Aristidis Vlamis, Panagiota Katikou. Climate influence on Dinophysis spp. spatial and temporal distributions in Greek coastal water. Plankton and Benthos Research. 2014; 9 (1):15-31.

Chicago/Turabian Style

Aristidis Vlamis; Panagiota Katikou. 2014. "Climate influence on Dinophysis spp. spatial and temporal distributions in Greek coastal water." Plankton and Benthos Research 9, no. 1: 15-31.

Journal article
Published: 01 January 2013 in Journal of AOAC INTERNATIONAL
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An interlaboratory collaborative study to validate a colorimetric phosphatase inhibition assay for quantitative determination of the okadaic acid (OA) toxins group in molluscs, OkaTest, was conducted. Eight test materials, including mussels, scallops, clams, and cockles, were analyzed as blind duplicates. Blank samples and materials containing different OA toxin levels ranging from 98 to 275 μg/kg OA equivalents were included. The study was carried out by a total of 16 laboratories from 11 different countries. Values obtained for repeatability relative standard deviations (RSDr) ranged from 5.4 to 11.2% (mean 7.5%). Reproducibility RSD (RSDR) values were between 7.6 and 13.2% (mean 9.9%). The Horwitz ratio (HorRat) values ranged between 0.4 and 0.6. A recovery assay was also carried out using a sample spiked with OA. A mean recovery of 98.0% and an RSD of 14.5% were obtained. The results obtained in this validation study indicate that the colorimetric phosphatase inhibition assay, OkaTest, is suitable for quantitative determination of the OA toxins group. OkaTest could be used as a test that is complementary to the reference method for monitoring the OA toxins group.

ACS Style

Henry Smienk; Elena Domínguez; María L Rodríguez-Velasco; David Clarke; Katrin Kapp; Panagiota Katikou; Ana G Cabado; Alberto Otero; Juan M Vieites; Pedro Razquin; Luis Mata. Quantitative Determination of the Okadaic Acid Toxins Group by a Colorimetric Phosphatase Inhibition Assay: Interlaboratory Study. Journal of AOAC INTERNATIONAL 2013, 96, 77 -85.

AMA Style

Henry Smienk, Elena Domínguez, María L Rodríguez-Velasco, David Clarke, Katrin Kapp, Panagiota Katikou, Ana G Cabado, Alberto Otero, Juan M Vieites, Pedro Razquin, Luis Mata. Quantitative Determination of the Okadaic Acid Toxins Group by a Colorimetric Phosphatase Inhibition Assay: Interlaboratory Study. Journal of AOAC INTERNATIONAL. 2013; 96 (1):77-85.

Chicago/Turabian Style

Henry Smienk; Elena Domínguez; María L Rodríguez-Velasco; David Clarke; Katrin Kapp; Panagiota Katikou; Ana G Cabado; Alberto Otero; Juan M Vieites; Pedro Razquin; Luis Mata. 2013. "Quantitative Determination of the Okadaic Acid Toxins Group by a Colorimetric Phosphatase Inhibition Assay: Interlaboratory Study." Journal of AOAC INTERNATIONAL 96, no. 1: 77-85.

Journal article
Published: 24 July 2012 in European Journal of Phycology
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A total of 92 cultured Pseudo-nitzschia strains, established between March 2007 and April 2010 from Greek coastal waters, were identified by using morphological and molecular (ITS2 region) characters. Twelve species were identified, among which P. brasiliana, P. subpacifica and P. hasleana were detected for the first time near Greek and East Mediterranean coasts. One P. delicatissima-like morphotype and another strain that closely resembled P. dolorosa were also found. Morphology and ITS2 phylogeny indicated that the level of diversity within the genus is higher than previously estimated (e.g. among P. delicatissima-like diatoms). Additionally, the ITS2 phylogeny revealed genetic variation within species, indicative of geographical differentiation (in P. brasiliana, P. fraudulenta, P. arenysensis, P. delicatissima and P. galaxiae). The majority of the cultured strains were also tested for domoic acid (DA) production. Strains of only three species, P. pseudodelicatissima, P. galaxiae and P. pungens var. pungens, were found capable of producing DA.

ACS Style

Kimon K. Moschandreou; Athanasios Baxevanis; Panagiota Katikou; Dimitra Papaefthimiou; Georgios Nikolaidis; Theodore J. Abatzopoulos. Inter- and intra-specific diversity of Pseudo-nitzschia (Bacillariophyceae) in the northeastern Mediterranean. European Journal of Phycology 2012, 47, 321 -339.

AMA Style

Kimon K. Moschandreou, Athanasios Baxevanis, Panagiota Katikou, Dimitra Papaefthimiou, Georgios Nikolaidis, Theodore J. Abatzopoulos. Inter- and intra-specific diversity of Pseudo-nitzschia (Bacillariophyceae) in the northeastern Mediterranean. European Journal of Phycology. 2012; 47 (3):321-339.

Chicago/Turabian Style

Kimon K. Moschandreou; Athanasios Baxevanis; Panagiota Katikou; Dimitra Papaefthimiou; Georgios Nikolaidis; Theodore J. Abatzopoulos. 2012. "Inter- and intra-specific diversity of Pseudo-nitzschia (Bacillariophyceae) in the northeastern Mediterranean." European Journal of Phycology 47, no. 3: 321-339.

Journal article
Published: 01 May 2012 in Food Chemistry
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Paula Rodríguez; Amparo Alfonso; Paz Otero; Panagiota Katikou; Dimitrios Georgantelis; Luis M Botana. Liquid chromatography–mass spectrometry method to detect Tetrodotoxin and Its analogues in the puffer fish Lagocephalus sceleratus (Gmelin, 1789) from European waters. Food Chemistry 2012, 132, 1103 -1111.

AMA Style

Paula Rodríguez, Amparo Alfonso, Paz Otero, Panagiota Katikou, Dimitrios Georgantelis, Luis M Botana. Liquid chromatography–mass spectrometry method to detect Tetrodotoxin and Its analogues in the puffer fish Lagocephalus sceleratus (Gmelin, 1789) from European waters. Food Chemistry. 2012; 132 (2):1103-1111.

Chicago/Turabian Style

Paula Rodríguez; Amparo Alfonso; Paz Otero; Panagiota Katikou; Dimitrios Georgantelis; Luis M Botana. 2012. "Liquid chromatography–mass spectrometry method to detect Tetrodotoxin and Its analogues in the puffer fish Lagocephalus sceleratus (Gmelin, 1789) from European waters." Food Chemistry 132, no. 2: 1103-1111.

Journal article
Published: 01 March 2012 in Toxicon
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Palytoxin (PlTX) is a marine toxin originally isolated from the zoantharians of the genus Palythoa. It is considered to be one of the most lethal marine toxins that block the Na⁺/K⁺-ATPase. This study was designed to investigate the acute effects of PlTX and ouabain, also an Na⁺/K⁺-ATPase blocker, on the mammalian peripheral nervous system using an ex vivo electrophysiological preparation: the isolated mouse sciatic nerve. Amplitude of the evoked nerve compound action potential (nCAP) was used to measure the proper functioning of the sciatic nerve fibres. The half-vitality time of the nerve fibres (the time required to inhibit the nCAP to 50% of its initial value: IT₅₀) incubated in normal saline was 24.5 ± 0.40 h (n = 5). Nerves incubated continuously in 50.0, 10.0, 1.0, 0.5, 0.250 and 0.125 nM of PlTX had an IT₅₀ of 0.06 ± 0.00, 0.51 ± 0.00, 2.1 ± 0.10, 8.9 ± 0.30, 15.1 ± 0.30 h, and 19.5 ± 0.20 h, respectively (n = 5, 3, 4, 4, 10). PlTX was extremely toxic to the sciatic nerve fibres, with a minimum effective concentration (mEC) of 0.125 nM (n = 5) and inhibitory concentration to 50% (IC₅₀) of 0.32 ± 0.08 nM (incubation time 24 h). Ouabain was far less toxic, with a mEC of 250.0 μM (n = 5) and IC₅₀ of 370.0 ± 18.00 μM (incubation 24.5 h). Finally, when the two compounds were combined--e.g. pre-incubation of the nerve fibre in 250.0 μM ouabain for 1 h and then exposure to 1.0 nM PlTX--ouabain offered minor a neuroprotection of 9.1-17.6% against PlTX-induced neurotoxicity. Higher concentrations of ouabain (500.0 μM) offered no protection. The mouse sciatic nerve preparation is a simple and low-cost bioassay that can be used to assess and quantify the neurotoxic effects of standard PlTX or PlTX-like compounds, since it appears to have the same sensitivity as the haemolysis of erythrocytes assay--the standard ex vivo test for PlTX toxicity.

ACS Style

Alexia Kagiava; Katerina Aligizaki; Panagiota Katikou; Georgios Nikolaidis; George Theophilidis. Assessing the neurotoxic effects of palytoxin and ouabain, both Na+/K+-ATPase inhibitors, on the myelinated sciatic nerve fibres of the mouse: An ex vivo electrophysiological study. Toxicon 2012, 59, 416 -426.

AMA Style

Alexia Kagiava, Katerina Aligizaki, Panagiota Katikou, Georgios Nikolaidis, George Theophilidis. Assessing the neurotoxic effects of palytoxin and ouabain, both Na+/K+-ATPase inhibitors, on the myelinated sciatic nerve fibres of the mouse: An ex vivo electrophysiological study. Toxicon. 2012; 59 (3):416-426.

Chicago/Turabian Style

Alexia Kagiava; Katerina Aligizaki; Panagiota Katikou; Georgios Nikolaidis; George Theophilidis. 2012. "Assessing the neurotoxic effects of palytoxin and ouabain, both Na+/K+-ATPase inhibitors, on the myelinated sciatic nerve fibres of the mouse: An ex vivo electrophysiological study." Toxicon 59, no. 3: 416-426.

Journal article
Published: 08 July 2011 in Food Additives & Contaminants: Part A
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International audienceContamination of shellfish with diarrhetic shellfish poisoning (DSP) toxins readily occurs during algal blooms. Such phenomena raise important public health concerns and thus comprise a constant challenge to shellfish farmers, the seafood industry and health services, considering the increasing occurrence of toxic episodes around the world. To avoid the detrimental effects of such episodes, research has focused on the use of various detoxification methodologies which should be rapid, efficient, easy to apply, and will not alter quality and sensory properties of shellfish. In the present study, both ozonation (15 mg kg-1 for 6 h) and γ-irradiation (6 kGy) have been utilized in order to reduce toxin content of contaminated shucked mussels, collected during the DSP episodes of 2007 and 2009 in Greece. DSP toxicity was detected using the mouse bioassay (MBA) while determination of toxin content of the okadaic acid (OA) group (both free and esterified forms) was conducted by LC/MS/MS analysis. Toxin reduction using γ-irradiation was in the range of 12-36%, 8-53% and 10-41% for free OA, OA esters and total OA respectively. Appearance and texture of irradiated mussels deteriorated, pointing to a low potential for commercial use of this method. Ozonation of mussels resulted in toxin reduction in the range of 6-100%, 25-83% and 21-66% for free OA, OA esters and total OA, respectively. Reduction of OA content was substantially higher in homogenized mussel tissue, compared to that of whole shucked mussels. In addition, differences detected with regard to quality parameters (TBA, sensory attributes) between ozonated and control mussels were not considerable. Eventhough varying % reductions in OA and its derivatives were achieved using ozonation under specific experimental conditions tested, it is postulated that upon optimization, ozonation may have the potential for post-harvest commercial DSP detoxification of shucked mussels

ACS Style

A.P. Louppis; Panagiota Katikou; D. Georgantelis; A.V. Badeka; M.G. Kontominas. Effect of ozonation and γ-irradiation on post-harvest decontamination of mussels (Mytillus galloprovincialis) containing diarrhetic shellfish toxins. Food Additives & Contaminants: Part A 2011, 28, 1 -10.

AMA Style

A.P. Louppis, Panagiota Katikou, D. Georgantelis, A.V. Badeka, M.G. Kontominas. Effect of ozonation and γ-irradiation on post-harvest decontamination of mussels (Mytillus galloprovincialis) containing diarrhetic shellfish toxins. Food Additives & Contaminants: Part A. 2011; 28 (12):1-10.

Chicago/Turabian Style

A.P. Louppis; Panagiota Katikou; D. Georgantelis; A.V. Badeka; M.G. Kontominas. 2011. "Effect of ozonation and γ-irradiation on post-harvest decontamination of mussels (Mytillus galloprovincialis) containing diarrhetic shellfish toxins." Food Additives & Contaminants: Part A 28, no. 12: 1-10.

Journal article
Published: 01 March 2011 in Toxicon
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Palytoxin (PlTX) and palytoxin-like (PlTX-like) compounds in seafood have been raising scientific concern in the last years. The constant increase in record numbers of the causative dinoflagellates of the genus Ostreopsis together with the large spatial expansion of this genus has led to intensification of research towards optimization of methods for determination of PlTX presence and toxicity. In this context, identification of seafood species which could possibly contain PlTXs constitutes an important issue for public health protection. In the present paper, worldwide occurrence of PlTX-like compounds in seafood is reviewed, while potential future strategies are discussed. PlTX has been reported to be present in several species of fish, crustaceans, molluscs and echinoderms. In one occasion, PlTX has been identified in freshwater puffer fish whereas all other records of PlTXs refer to marine species and have been recorded in latitudes approximately between 43°N and 15°S. PlTX determination in seafood has relied on different methodologies (mainly LC-MS, mouse bioassay and hemolysis neutralization assay) that have evolved over time. Future recommendations include systematic screening of PlTX in those species and areas where PlTX has already been recorded implementing updated methodologies.

ACS Style

Katerina Aligizaki; Panagiota Katikou; Anna Milandri; Jorge Diogène. Occurrence of palytoxin-group toxins in seafood and future strategies to complement the present state of the art. Toxicon 2011, 57, 390 -399.

AMA Style

Katerina Aligizaki, Panagiota Katikou, Anna Milandri, Jorge Diogène. Occurrence of palytoxin-group toxins in seafood and future strategies to complement the present state of the art. Toxicon. 2011; 57 (3):390-399.

Chicago/Turabian Style

Katerina Aligizaki; Panagiota Katikou; Anna Milandri; Jorge Diogène. 2011. "Occurrence of palytoxin-group toxins in seafood and future strategies to complement the present state of the art." Toxicon 57, no. 3: 390-399.

Journal article
Published: 01 May 2010 in Phycologia
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Moschandreou K.K., Papaefthimiou D., Katikou P., Kalopesa E., Panou A. and Nikolaidis G. 2010. Morphology, phylogeny and toxin analysis of Pseudo-nitschia pseudodelicatissima (Bacillariophyceae) isolated from the Thermaikos Gulf, Greece. Phycologia 49: 260–273. DOI: 10.2216/09-42.1 Pseudo-nitzschia pseudodelicatissima is a diatom species that has been associated with the production of the neurotoxin domoic acid (DA), causative agent of amnesic shellfish poisoning. However, the taxonomic revision of this species complex resulted in uncertain identity and, subsequently, toxicity of the strains tentatively identified under light microscope as P. pseudodelicatissima. Six strains isolated from the Thermaikos Gulf during the period from August to October 2008 were cultured and tested for production of DA. All strains were studied in morphological detail using electron microscopy and were identified as P. pseudodelicatissima. The identification was supported by phylogenetic analyses of the large subunit (LSU) and internal transcribed spacer (ITS) ribosomal rDNA regions, along with the secondary structure of ITS-2 rDNA region. DA was detected in all cultures and in three of the strains in quantifiable amounts up to 3.08 ng ml−1. Two of the strains were studied over the course of a batch culture growth experiment and DA was detected from the mid-exponential until late-stationary phases; the maximum whole-culture DA levels were measured in late-exponential to early-stationary phases. This study confirms the production of DA by P. pseudodelicatissima in culture.

ACS Style

Kimon K. Moschandreou; Dimitra Papaefthimiou; Panagiota Katikou; Eleni Kalopesa; Alexandra Panou; Georgios Nikolaidis. Morphology, phylogeny and toxin analysis of Pseudo-nitzschia pseudodelicatissima (Bacillariophyceae) isolated from the Thermaikos Gulf, Greece. Phycologia 2010, 49, 260 -273.

AMA Style

Kimon K. Moschandreou, Dimitra Papaefthimiou, Panagiota Katikou, Eleni Kalopesa, Alexandra Panou, Georgios Nikolaidis. Morphology, phylogeny and toxin analysis of Pseudo-nitzschia pseudodelicatissima (Bacillariophyceae) isolated from the Thermaikos Gulf, Greece. Phycologia. 2010; 49 (3):260-273.

Chicago/Turabian Style

Kimon K. Moschandreou; Dimitra Papaefthimiou; Panagiota Katikou; Eleni Kalopesa; Alexandra Panou; Georgios Nikolaidis. 2010. "Morphology, phylogeny and toxin analysis of Pseudo-nitzschia pseudodelicatissima (Bacillariophyceae) isolated from the Thermaikos Gulf, Greece." Phycologia 49, no. 3: 260-273.

Journal article
Published: 01 April 2010 in Toxicon
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An approach involving both chemical and biological methods was undertaken for the detection and quantification of the marine toxins okadaic acid (OA), dinophysistoxin-1 (DTX-1) and their respective esters in mussels from different sampling sites in Greece during the period 2006-2007. Samples were analyzed by means of a) high performance liquid chromatography with fluorometric detection (HPLC-FLD), using 9-athryldiazomethane (ADAM), as a pre-column derivatization reagent, b) liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) and c) the mouse bioassay. Free OA and DTX-1 were determined by both HPLC-FLD and LC-MS/MS, while their respective esters were determined only by LC-MS/MS after alkaline hydrolysis of the samples. The detection limit (L.O.D.) and quantification limit (L.O.Q.) of the HPLC-FLD method were 0.015 microg/g HP and 0.050 microg/g HP, respectively, for OA. The detection limit (L.O.D.) and quantification limit (L.O.Q.) of the LC-MS/MS method were 0.045 microg/g HP and 0.135 microg/g HP, respectively, for OA. Comparison of results between the two analytical methods showed excellent agreement (100%), while both HPLC-FLD and LC-MS/MS methods showed an agreement of 97.1% compared to the mouse bioassay.

ACS Style

Artemis P. Louppis; Anastasia V. Badeka; Panagiota Katikou; Evangelos K. Paleologos; Michael G. Kontominas. Determination of okadaic acid, dinophysistoxin-1 and related esters in Greek mussels using HPLC with fluorometric detection, LC-MS/MS and mouse bioassay. Toxicon 2010, 55, 724 -733.

AMA Style

Artemis P. Louppis, Anastasia V. Badeka, Panagiota Katikou, Evangelos K. Paleologos, Michael G. Kontominas. Determination of okadaic acid, dinophysistoxin-1 and related esters in Greek mussels using HPLC with fluorometric detection, LC-MS/MS and mouse bioassay. Toxicon. 2010; 55 (4):724-733.

Chicago/Turabian Style

Artemis P. Louppis; Anastasia V. Badeka; Panagiota Katikou; Evangelos K. Paleologos; Michael G. Kontominas. 2010. "Determination of okadaic acid, dinophysistoxin-1 and related esters in Greek mussels using HPLC with fluorometric detection, LC-MS/MS and mouse bioassay." Toxicon 55, no. 4: 724-733.

Journal article
Published: 31 July 2009 in Toxicon
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According to the current European Union legislative requirements (Regulation 853/2004/EC; Regulation 854/2004/EC, poisonous fish of the family Tetraodontidae and products derived from them must not be placed on the European markets. Following the increased publicity regarding the presence of the pufferfish species Lagocephalus sceleratus in Greek waters, this study was undertaken in order to confirm its toxicity and assess the risk of poisoning in case of accidental consumption. Acidic extracts from tissues of L. sceleratus specimens of different sizes were examined by means of the official mouse bioassay for tetrodotoxin, while some of the extracts were also tested for the presence of Paralytic Shellfish Poisoning (PSP) toxins with a commercial ELISA kit. Toxicity in mice, with symptomatology indicative of tetrodotoxin, was confirmed in a number of samples and indicated a correlation with fish size. Toxicity of certain tissues (liver, gonads, gastrointestinal tract) in larger individuals, expressed as microg/g tetrodotoxin equivalents, was largely above levels required to cause death in human adults. On the other hand, all tested extracts provided a positive reaction in the ELISA test for PSP toxins. This constitutes the first report for presence of toxicity in L. sceleratus caught in European coastal waters.

ACS Style

Panagiota Katikou; Dimitrios Georgantelis; Nikolaos Sinouris; Anastasia Petsi; Theodoros Fotaras. First report on toxicity assessment of the Lessepsian migrant pufferfish Lagocephalus sceleratus (Gmelin, 1789) from European waters (Aegean Sea, Greece). Toxicon 2009, 54, 50 -55.

AMA Style

Panagiota Katikou, Dimitrios Georgantelis, Nikolaos Sinouris, Anastasia Petsi, Theodoros Fotaras. First report on toxicity assessment of the Lessepsian migrant pufferfish Lagocephalus sceleratus (Gmelin, 1789) from European waters (Aegean Sea, Greece). Toxicon. 2009; 54 (1):50-55.

Chicago/Turabian Style

Panagiota Katikou; Dimitrios Georgantelis; Nikolaos Sinouris; Anastasia Petsi; Theodoros Fotaras. 2009. "First report on toxicity assessment of the Lessepsian migrant pufferfish Lagocephalus sceleratus (Gmelin, 1789) from European waters (Aegean Sea, Greece)." Toxicon 54, no. 1: 50-55.

Journal article
Published: 28 February 2009 in Toxicon
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An approach involving chemical, functional and biological techniques was taken for the detection and quantification of the marine toxin okadaic acid (OA) in mussels from Thermaikos and Saronikos Gulfs, Greece, during DSP episodes that occurred in 2006-2007. Samples were analyzed using the mouse bioassay, high performance liquid chromatography with fluorimetric detection (HPLC-FLD), using l-bromoacetylpyrene (BAP), as a precolumn derivatisation reagent, and the protein phosphatase 2A inhibition assay (PP2AIA) using a commercially available kit. Okadaic acid (OA) and its polar and non-polar esters were detected and quantified by HPLC-FLD, after hydrolysis of the samples during preparation. The detection limit of the HPLC method for OA was 5.86 microg OA/kg, which permits this method to be used for the regulatory control of these toxins in shellfish. Comparison of the results by all three methods revealed excellent consistency.

ACS Style

Eleanna Prassopoulou; Panagiota Katikou; Dimitrios Georgantelis; Apostolos Kyritsakis. Detection of okadaic acid and related esters in mussels during diarrhetic shellfish poisoning (DSP) episodes in Greece using the mouse bioassay, the PP2A inhibition assay and HPLC with fluorimetric detection. Toxicon 2009, 53, 214 -227.

AMA Style

Eleanna Prassopoulou, Panagiota Katikou, Dimitrios Georgantelis, Apostolos Kyritsakis. Detection of okadaic acid and related esters in mussels during diarrhetic shellfish poisoning (DSP) episodes in Greece using the mouse bioassay, the PP2A inhibition assay and HPLC with fluorimetric detection. Toxicon. 2009; 53 (2):214-227.

Chicago/Turabian Style

Eleanna Prassopoulou; Panagiota Katikou; Dimitrios Georgantelis; Apostolos Kyritsakis. 2009. "Detection of okadaic acid and related esters in mussels during diarrhetic shellfish poisoning (DSP) episodes in Greece using the mouse bioassay, the PP2A inhibition assay and HPLC with fluorimetric detection." Toxicon 53, no. 2: 214-227.

Journal article
Published: 31 January 2009 in Harmful Algae
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ACS Style

Katerina Aligizaki; Georgios Nikolaidis; Panagiota Katikou; Athanasios Baxevanis; Theodore J. Abatzopoulos. Potentially toxic epiphytic Prorocentrum (Dinophyceae) species in Greek coastal waters. Harmful Algae 2009, 8, 299 -311.

AMA Style

Katerina Aligizaki, Georgios Nikolaidis, Panagiota Katikou, Athanasios Baxevanis, Theodore J. Abatzopoulos. Potentially toxic epiphytic Prorocentrum (Dinophyceae) species in Greek coastal waters. Harmful Algae. 2009; 8 (2):299-311.

Chicago/Turabian Style

Katerina Aligizaki; Georgios Nikolaidis; Panagiota Katikou; Athanasios Baxevanis; Theodore J. Abatzopoulos. 2009. "Potentially toxic epiphytic Prorocentrum (Dinophyceae) species in Greek coastal waters." Harmful Algae 8, no. 2: 299-311.

Comparative study
Published: 10 December 2008 in Bioscience Reports
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Palytoxin is one of the most complex and biggest molecules known to show extreme acute toxicity. The dinoflagellate Ostreopsis spp., the producer organism of palytoxin, has been shown to be distributed worldwide, thus making palytoxin an emerging toxin. Rat-derived hepatocytes (Clone 9) and BE (2)-M17 human neuroblastoma cells were used to test palytoxin or palytoxin-like compounds by measuring the cell metabolic rate with Alamar Blue. The dose-dependent decrease in viability was specifically inhibited by ouabain in the case of BE (2)-M17 neuroblastoma cells. This is a functional, dynamic and simple test for palytoxins with high sensitivity (as low as 0.2 ng/ml). This method was useful for toxin detection in Ostreopsis extracts and naturally contaminated mussel samples. A comparative study testing toxic mussel extracts by LC (liquid chromatography)-MS/MS (tandem MS), MBA (mouse bioassay), haemolysis neutralization assay and a cytotoxicity test indicated that our method is suitable for the routine determination and monitoring of palytoxins and palytoxin-like compounds.

ACS Style

Begoña Espiña; Eva Cagide; M. Carmen Louzao; Maria M. Fernandez; Mercedes Rodriguez Vieytes; Panagiota Katikou; Adriano Villar; David Jaen; Luz Maman; Luis M. Botana. Specific and dynamic detection of palytoxins by in vitro microplate assay with human neuroblastoma cells. Bioscience Reports 2008, 29, 13 -23.

AMA Style

Begoña Espiña, Eva Cagide, M. Carmen Louzao, Maria M. Fernandez, Mercedes Rodriguez Vieytes, Panagiota Katikou, Adriano Villar, David Jaen, Luz Maman, Luis M. Botana. Specific and dynamic detection of palytoxins by in vitro microplate assay with human neuroblastoma cells. Bioscience Reports. 2008; 29 (1):13-23.

Chicago/Turabian Style

Begoña Espiña; Eva Cagide; M. Carmen Louzao; Maria M. Fernandez; Mercedes Rodriguez Vieytes; Panagiota Katikou; Adriano Villar; David Jaen; Luz Maman; Luis M. Botana. 2008. "Specific and dynamic detection of palytoxins by in vitro microplate assay with human neuroblastoma cells." Bioscience Reports 29, no. 1: 13-23.