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Special Issue "Emerging Marine Biotoxins"

A special issue of Toxins (ISSN 2072-6651). This special issue belongs to the section "Marine and Freshwater Toxins".

Deadline for manuscript submissions: closed (31 October 2018)

Special Issue Editors

Guest Editor
Prof. Dr. Ana Gago-Martínez

Departamento de Química Analítica y Alimentaria, Facultad de Química (Campus de Vigo), Universidad de Vigo, As Lagoas-Marcosende 36310 Vigo (Pontevedra), Spain
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Guest Editor
Dr. Arjen Gerssen

RIKILT Wageningen Research, Akkermaalsbos 2, 6708WB, Wageningen, The Netherlands
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Special Issue Information

Dear Colleagues,

Emerging toxins, such as tetrodotoxins, ciguatoxins, palytoxins cyclic imines and others, which were mostly reported and related to certain geographical areas, are recently occurring in places where they have never been reported before. Climate change has been considered a key factor in the expansion of these toxins to new areas; however, this can be also be due to more intense biological invasions, more sensitive analytical methods, or even an increased scientific interest in these natural contaminations. The incidences of human intoxications due to the consumption of seafood contaminated with these toxins makes their study an important task to accomplish in order to protect human health.

This Special Issue will cover all emerging toxins that might be considered as a threat to human health, and different aspects, including analytical methods for detection and quantification, rapid tests for screening, toxicology, mode of action, occurrence, epidemiology, are considered as the main areas of interest.

Prof. Dr. Ana Gago-Martínez
Dr. Arjen Gerssen
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a double-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Toxins is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Emerging marine biotoxins
  • Analytical methods
  • Detection and Quantification
  • Rapid tests
  • Screening
  • Toxicology
  • Mode of action
  • Occurrence and Epidemiology

Published Papers (14 papers)

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Editorial

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Open AccessEditorial
Emerging Marine Biotoxins
Received: 28 May 2019 / Accepted: 30 May 2019 / Published: 3 June 2019
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Abstract
The emergence of marine biotoxins in geographical areas where they have never been reported before is a concern of considerable impact on seafood contamination, and consequently, on public health [...] Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)

Research

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Open AccessArticle
An Attempt to Characterize the Ciguatoxin Profile in Seriola fasciata Causing Ciguatera Fish Poisoning in Macaronesia
Received: 19 March 2019 / Revised: 9 April 2019 / Accepted: 10 April 2019 / Published: 13 April 2019
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Abstract
Ciguatera Fish Poisoning is a worldwide concern caused by the consumption of fish contaminated with ciguatoxins not only in endemic regions in the Pacific Ocean or the Caribbean Sea but also in emerging areas of Macaronesia on the eastern Atlantic. The recent emergence [...] Read more.
Ciguatera Fish Poisoning is a worldwide concern caused by the consumption of fish contaminated with ciguatoxins not only in endemic regions in the Pacific Ocean or the Caribbean Sea but also in emerging areas of Macaronesia on the eastern Atlantic. The recent emergence of these toxins in other coastal areas worldwide, prompted the need for the characterization of the risk in these areas. This Ciguatera Fish Poisoning risk has been recently identified as a potential threat in subtropical areas of the Atlantic coast and scientific efforts are being focused in the identification and confirmation of the toxins involved in this potential risk. Neuroblastoma cell assay has been widely used for the evaluation of the toxicity in several marine biotoxin groups, and found to be a very useful tool for toxicity screening. LC-MS/MS has been also used for confirmatory purposes although the main limitation of the advances on LC-MS/MS development is due to commercial unavailability of reference materials and hampers method implementation and validation or even confirmation of the ciguatoxins (CTXs) responsible for the toxic profiles. While neuroblastoma cell assay (N2a) is typically used for toxicity screening as mentioned above, being necessary to confirm this N2a toxicity by LC-MS/MS, this study is designed using N2a as a tool to confirm the toxicity of the fractions obtained corresponding to potential CTXs analogues according to the analysis by LC-MS/MS. With this aim, an amberjack sample (Seriola fasciata) from Selvagen Islads (Portugal) and implicated in Ciguatera Fish Poisoning was analyzed by LC-MS/MS and Caribbean Ciguatoxins were found to be mainly responsible for the toxicity. N2a was used in this work as a tool to help in the confirmation of the toxicity of fractions obtained by HPLC. Caribbean Ciguatoxin-1 was found as the main analogue responsible for the N2a toxicity while three Caribbean Ciguatoxin-1 (C-CTX1) metabolites which contribute to the total toxicity were also identified. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
Distribution of Toxigenic Halomicronema spp. in Adjacent Environments on the Island of Ischia: Comparison of Strains from Thermal Waters and Free Living in Posidonia Oceanica Meadows
Received: 19 December 2018 / Revised: 28 January 2019 / Accepted: 1 February 2019 / Published: 8 February 2019
Cited by 1 | PDF Full-text (3416 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Organisms adaptable to extreme conditions share the ability to establish protective biofilms or secrete defence toxins. The extracellular substances that are secreted may contain monosaccharides and other toxic compounds, but environmental conditions influence biofilm characteristics. Microorganisms that are present in the same environment [...] Read more.
Organisms adaptable to extreme conditions share the ability to establish protective biofilms or secrete defence toxins. The extracellular substances that are secreted may contain monosaccharides and other toxic compounds, but environmental conditions influence biofilm characteristics. Microorganisms that are present in the same environment achieve similar compositions, regardless of their phylogenetic relationships. Alternatively, cyanobacteria phylogenetically related may live in different environments, but we ignore if their physiological answers may be similar. To test this hypothesis, two strains of cyanobacteria that were both ascribed to the genus Halomicronema were isolated. H. metazoicum was isolated in marine waters off the island of Ischia (Bay of Naples, Italy), free living on leaves of Posidonia oceanica. Halomicronema sp. was isolated in adjacent thermal waters. Thus, two congeneric species adapted to different environments but diffused in the same area were polyphasically characterized by microscopy, molecular, and toxicity analyses. A variable pattern of toxicity was exhibited, in accordance with the constraints imposed by the host environments. Cyanobacteria adapted to extreme environments of thermal waters face a few competitors and exhibit a low toxicity; in contrast, congeneric strains that have adapted to stable and complex environments as seagrass meadows compete with several organisms for space and resources, and they produce toxic compounds that are constitutively secreted in the surrounding waters. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
A Sensitive LC-MS/MS Method for Palytoxin Using Lithium Cationization
Toxins 2018, 10(12), 537; https://doi.org/10.3390/toxins10120537
Received: 30 October 2018 / Revised: 10 December 2018 / Accepted: 11 December 2018 / Published: 14 December 2018
Cited by 1 | PDF Full-text (1746 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Palytoxin (PlTX) and analogues are produced by certain dinoflagellates, sea anemones, corals and cyanobacteria. PlTX can accumulate in the food chain and when consumed it may cause intoxication with symptoms like myalgia, weakness, fever, nausea, and vomiting. The analysis of PlTXs is challenging, [...] Read more.
Palytoxin (PlTX) and analogues are produced by certain dinoflagellates, sea anemones, corals and cyanobacteria. PlTX can accumulate in the food chain and when consumed it may cause intoxication with symptoms like myalgia, weakness, fever, nausea, and vomiting. The analysis of PlTXs is challenging, and because of the large molecular structure, it is difficult to develop a sensitive and selective liquid chromatography-mass spectrometry (LC-MS/MS) method. In this work, an LC-MS/MS method was developed to analyse PlTXs with use of lithium iodine and formic acid as additives in the mobile phase. For method development, initially, LC-hrMS was used to accurately determine the elemental composition of the precursor and product ions. The main adduct formed was [M + H + 2Li]3+. Fragments were identified with LC-hrMS and these were incorporated in the LC-MS/MS method. A method of 10 min was developed and a solid phase extraction clean-up procedure was optimised for shellfish matrix. The determined limits of detection were respectively 8 and 22 µg PlTX kg−1 for mussel and oyster matrix. Oysters gave a low recovery of approximately 50% for PlTX during extraction. The method was successfully in-house validated, repeatability had a relative standard deviation less than 20% (n = 5) at 30 µg PlTX kg−1 in mussel, cockle, and ensis, and at 60 µg PlTX kg−1 in oyster. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
Cyanobacterial Neurotoxin Beta-Methyl-Amino-l-Alanine Affects Dopaminergic Neurons in Optic Ganglia and Brain of Daphnia magna
Toxins 2018, 10(12), 527; https://doi.org/10.3390/toxins10120527
Received: 18 November 2018 / Revised: 2 December 2018 / Accepted: 6 December 2018 / Published: 8 December 2018
Cited by 1 | PDF Full-text (3545 KB) | HTML Full-text | XML Full-text
Abstract
The non-proteinogenic amino acid beta-methyl-amino-l-alanine (BMAA) is a neurotoxin produced by cyanobacteria. BMAA accumulation in the brain of animals via biomagnification along the food web can contribute to the development of neurodegenerative diseases such as Amyotrophic lateral sclerosis/Parkinsonism dementia complex (ALS/PDC), [...] Read more.
The non-proteinogenic amino acid beta-methyl-amino-l-alanine (BMAA) is a neurotoxin produced by cyanobacteria. BMAA accumulation in the brain of animals via biomagnification along the food web can contribute to the development of neurodegenerative diseases such as Amyotrophic lateral sclerosis/Parkinsonism dementia complex (ALS/PDC), the latter being associated with a loss of dopaminergic neurons. Daphnia magna is an important microcrustacean zooplankton species that plays a key role in aquatic food webs, and BMAA-producing cyanobacteria often form part of their diet. Here, we tested the effects of BMAA on putative neurodegeneration of newly identified specific dopaminergic neurons in the optic ganglia/brain complex of D. magna using quantitative tyrosine-hydroxylase immunohistochemistry and fluorescence cytometry. The dopaminergic system was analysed in fed and starved isogenic D. magna adults incubated under different BMAA concentrations over 4 days. Increased BMAA concentration showed significant decrease in the stainability of dopaminergic neurons of D. magna, with fed animals showing a more extreme loss. Furthermore, higher BMAA concentrations tended to increase offspring mortality during incubation. These results are indicative of ingested BMAA causing neurodegeneration of dopaminergic neurons in D. magna and adversely affecting reproduction. This may imply similar effects of BMAA on known human neurodegenerative diseases involving dopaminergic neurons. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessFeature PaperArticle
New Insights into the Occurrence and Toxin Profile of Ciguatoxins in Selvagens Islands (Madeira, Portugal)
Toxins 2018, 10(12), 524; https://doi.org/10.3390/toxins10120524
Received: 5 November 2018 / Revised: 4 December 2018 / Accepted: 5 December 2018 / Published: 7 December 2018
Cited by 4 | PDF Full-text (1034 KB) | HTML Full-text | XML Full-text
Abstract
Ciguatoxins (CTXs), endemic from tropical and subtropical regions of the Pacific and Indian Ocean and the Caribbean Sea, have caused several human poisonings during the last decade in Europe. Ciguatera fish poisonings (CFP) in Madeira and Canary Islands appear to be particularly related [...] Read more.
Ciguatoxins (CTXs), endemic from tropical and subtropical regions of the Pacific and Indian Ocean and the Caribbean Sea, have caused several human poisonings during the last decade in Europe. Ciguatera fish poisonings (CFP) in Madeira and Canary Islands appear to be particularly related with consumption of fish caught close to Selvagens Islands, a Portuguese natural reserve composed of three small islands that harbor high fish biomass. In this study, fish specimens considered as potential vectors of CTXs were caught in Madeira and Selvagens archipelagos for toxins determination via sensitive liquid chromatography with tandem mass spectrometry detection (LC–MS/MS). CTXs were found in most of the fish samples from Selvagens and none from Madeira. Caribbean ciguatoxin-1 (C-CTX1) was the only toxin congener determined, reaching the highest value of 0.25 µg C-CTX1 kg−1 in a 4.6 kg island grouper (Mycteroperca fusca). This study indicates that a diversity of fish from different trophic levels contains CTXs, Selvagens appear to be one of the most favorable locations for CTXs food web transfer and finally, this study highlights the need of further research based on intensive environmental and biological sampling on these remote islands. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
Whole-Genome Sequencing of Chinese Yellow Catfish Provides a Valuable Genetic Resource for High-Throughput Identification of Toxin Genes
Toxins 2018, 10(12), 488; https://doi.org/10.3390/toxins10120488
Received: 11 October 2018 / Revised: 15 November 2018 / Accepted: 19 November 2018 / Published: 23 November 2018
Cited by 2 | PDF Full-text (2490 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Naturally derived toxins from animals are good raw materials for drug development. As a representative venomous teleost, Chinese yellow catfish (Pelteobagrus fulvidraco) can provide valuable resources for studies on toxin genes. Its venom glands are located in the pectoral and dorsal [...] Read more.
Naturally derived toxins from animals are good raw materials for drug development. As a representative venomous teleost, Chinese yellow catfish (Pelteobagrus fulvidraco) can provide valuable resources for studies on toxin genes. Its venom glands are located in the pectoral and dorsal fins. Although with such interesting biologic traits and great value in economy, Chinese yellow catfish is still lacking a sequenced genome. Here, we report a high-quality genome assembly of Chinese yellow catfish using a combination of next-generation Illumina and third-generation PacBio sequencing platforms. The final assembly reached 714 Mb, with a contig N50 of 970 kb and a scaffold N50 of 3.65 Mb, respectively. We also annotated 21,562 protein-coding genes, in which 97.59% were assigned at least one functional annotation. Based on the genome sequence, we analyzed toxin genes in Chinese yellow catfish. Finally, we identified 207 toxin genes and classified them into three major groups. Interestingly, we also expanded a previously reported sex-related region (to ≈6 Mb) in the achieved genome assembly, and localized two important toxin genes within this region. In summary, we assembled a high-quality genome of Chinese yellow catfish and performed high-throughput identification of toxin genes from a genomic view. Therefore, the limited number of toxin sequences in public databases will be remarkably improved once we integrate multi-omics data from more and more sequenced species. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
First Report on the Occurrence of Tetrodotoxins in Bivalve Mollusks in The Netherlands
Toxins 2018, 10(11), 450; https://doi.org/10.3390/toxins10110450
Received: 30 August 2018 / Revised: 30 October 2018 / Accepted: 30 October 2018 / Published: 1 November 2018
Cited by 7 | PDF Full-text (2413 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Tetrodotoxin (TTX) is traditionally associated with seafood from tropical regions, but recently TTX was detected in bivalve mollusks in more temperate European waters. In The Netherlands it was therefore decided to monitor TTX in shellfish harvested from Dutch production areas. All shellfish production [...] Read more.
Tetrodotoxin (TTX) is traditionally associated with seafood from tropical regions, but recently TTX was detected in bivalve mollusks in more temperate European waters. In The Netherlands it was therefore decided to monitor TTX in shellfish harvested from Dutch production areas. All shellfish production areas were monitored in 2015, 2016 and 2017. Samples were analyzed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). In total 1063 samples were investigated, and the highest concentrations were observed in 2016, i.e., 253 µg TTX/kg in oysters and 101 µg TTX/kg in mussels. No TTX analogues, with the exception of 4-epi-TTX in one single sample, were found and contaminated samples also showed positive results in the neuro-2a bioassay. The occurrence of TTX seems to be consistent over the last three years with the highest concentrations observed annually in late June. The causative organism and the reasons why specific Dutch production areas are affected while others are not, are still unclear. Initially in The Netherlands an action limit of 20 µg TTX/kg was used to ensure the safety of consumers (2016), but recently The European Food Safety Authority (EFSA) established an acute reference dose, and based on a high portion size of consuming 400 g mussels, this dose was translated into a safe concentration of 44 µg TTX per kg for shellfish. This concentration is now used as an action limit and TTX is formally included in the Dutch shellfish monitoring program. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
Nuclear Magnetic Resonance seq (NMRseq): A New Approach to Peptide Sequence Tags
Toxins 2018, 10(11), 437; https://doi.org/10.3390/toxins10110437
Received: 14 October 2018 / Accepted: 25 October 2018 / Published: 28 October 2018
Cited by 1 | PDF Full-text (1502 KB) | HTML Full-text | XML Full-text
Abstract
Structural analysis of peptides with nuclear magnetic resonance (NMR) spectroscopy generally relies on knowledge of the primary sequence to enable assignment of the resonances prior to determination of the three-dimensional structure. Resonance assignment without knowledge of the sequence is complicated by redundancy in [...] Read more.
Structural analysis of peptides with nuclear magnetic resonance (NMR) spectroscopy generally relies on knowledge of the primary sequence to enable assignment of the resonances prior to determination of the three-dimensional structure. Resonance assignment without knowledge of the sequence is complicated by redundancy in amino acid type, making complete de novo sequencing using NMR spectroscopy unlikely to be feasible. Despite this redundancy, we show here that NMR spectroscopy can be used to identify short sequence tags that can be used to elucidate full-length peptide sequences via database searching. In the current study, we have used this approach to identify conotoxins from the venom of the cone snail Conus geographus and determined the three-dimensional structure of a member of the I3 superfamily. This approach is most likely to be useful for the characterization of disulfide-rich peptides, such as those that were chosen for this study, as they generally have well-defined structures, which enhances the quality of the NMR spectra. In contrast to other sequencing methods, the lack of sample manipulation, such as protease digestion, allows for subsequent bioassays to be carried out using the native sample used for sequence identification. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
The Acute Toxicity of Tetrodotoxin and Tetrodotoxin–Saxitoxin Mixtures to Mice by Various Routes of Administration
Toxins 2018, 10(11), 423; https://doi.org/10.3390/toxins10110423
Received: 8 October 2018 / Revised: 19 October 2018 / Accepted: 19 October 2018 / Published: 23 October 2018
Cited by 3 | PDF Full-text (666 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Tetrodotoxin (TTX) is a potent neurotoxin associated with human poisonings through the consumption of pufferfish. More recently, TTX has been identified in bivalve molluscs from diverse geographical environments, including Europe, and is therefore recognised as an emerging threat to food safety. A recent [...] Read more.
Tetrodotoxin (TTX) is a potent neurotoxin associated with human poisonings through the consumption of pufferfish. More recently, TTX has been identified in bivalve molluscs from diverse geographical environments, including Europe, and is therefore recognised as an emerging threat to food safety. A recent scientific opinion of the EFSA Panel on Contaminants in the Food Chain recognised the need for further data on the acute oral toxicity of TTX and suggested that, since saxitoxin (STX) and TTX had similar modes of action, it was possible that their toxicities were additive so could perhaps be combined to yield one health-based guideline value. The present study determined the toxicity of TTX by various routes of administration. The testing of three different mixtures of STX and TTX and comparing the experimentally determined values to those predicted on the basis of additive toxicity demonstrated that the toxicities of STX and TTX are additive. This illustrates that it is appropriate to treat TTX as a member of the paralytic shellfish group of toxins. Since the toxicity of TTX was found to be the same as STX by feeding, a molar toxicity equivalence factor of 1.0 for TTX can be applied. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
Extended Targeted and Non-Targeted Strategies for the Analysis of Marine Toxins in Mussels and Oysters by (LC-HRMS)
Received: 11 July 2018 / Revised: 27 August 2018 / Accepted: 11 September 2018 / Published: 14 September 2018
Cited by 2 | PDF Full-text (1981 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
When considering the geographical expansion of marine toxins, the emergence of new toxins and the associated risk for human health, there is urgent need for versatile and efficient analytical methods that are able to detect a range, as wide as possible, of known [...] Read more.
When considering the geographical expansion of marine toxins, the emergence of new toxins and the associated risk for human health, there is urgent need for versatile and efficient analytical methods that are able to detect a range, as wide as possible, of known or emerging toxins. Current detection methods for marine toxins rely on a priori defined target lists of toxins and are generally inappropriate for the detection and identification of emerging compounds. The authors describe the implementation of a recent approach for the non-targeted analysis of marine toxins in shellfish with a focus on a comprehensive workflow for the acquisition and treatment of the data generated after liquid chromatography coupled with high resolution mass spectrometry (LC-HRMS) analysis. First, the study was carried out in targeted mode to assess the performance of the method for known toxins with an extended range of polarities, including lipophilic toxins (okadaic acid, dinophysistoxins, azaspiracids, pectenotoxins, yessotoxins, cyclic imines, brevetoxins) and domoic acid. The targeted method, assessed for 14 toxins, shows good performance both in mussel and oyster extracts. The non-target potential of the method was then challenged via suspects and without a priori screening by blind analyzing mussel and oyster samples spiked with marine toxins. The data processing was optimized and successfully identified the toxins that were spiked in the blind samples. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
Microcystin Content in Phytoplankton and in Small Fish from Eutrophic Nyanza Gulf, Lake Victoria, Kenya
Received: 23 April 2018 / Revised: 26 June 2018 / Accepted: 2 July 2018 / Published: 3 July 2018
Cited by 4 | PDF Full-text (2940 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The human health risks posed by exposure to cyanobacterial toxins such as microcystin (MC) through water and fish consumption remain poorly described. During the last two decades, coastal regions of Lake Victoria such as Nyanza Gulf (Kisumu Bay) have shown severe signs of [...] Read more.
The human health risks posed by exposure to cyanobacterial toxins such as microcystin (MC) through water and fish consumption remain poorly described. During the last two decades, coastal regions of Lake Victoria such as Nyanza Gulf (Kisumu Bay) have shown severe signs of eutrophication with blooms formed by Microcystis producing MC. In this study, the spatial variability in MC concentration in Kisumu Bay was investigated which was mostly caused by Microcystis buoyancy and wind drifting. Small fish (<6 cm) mainly composed of Rastrineobola argentea were examined for MC content by means of biological methods such as ELISA and protein phosphatase inhibition assay (PPIA) and partly by chemical-analytical methods such as LC-MS/MS. Overall, the MC content in small fish was related to the MC content observed in the seston. When comparing the MC content in the seston in relation to dry weight with the MC content in small fish the latter was found three orders of magnitude decreased. On average, the ELISA-determined MC contents exceeded the PPIA-determined MC contents by a factor of 8.2 ± 0.5 (SE) while the MC contents as determined by LC-MS/MS were close to the detection limit. Using PPIA, the MC content varied from 25–109 (mean 62 ± 7) ng/g fish dry weight in Kisumu Bay vs. 14 ± 0.8 ng MC/g in the more open water of L. Victoria at Rusinga channel. Drying the fish under the sun showed little effect on MC content, although increased humidity might indirectly favor photocatalyzed MC degradation. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
Growth and Toxin Production of Gambierdiscus spp. Can Be Regulated by Quorum-Sensing Bacteria
Received: 19 May 2018 / Revised: 20 June 2018 / Accepted: 20 June 2018 / Published: 22 June 2018
Cited by 1 | PDF Full-text (3081 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Gambierdiscus spp. are the major culprit responsible for global ciguatera fish poisoning (CFP). At present, the effects of microbiological factors on algal proliferation and toxin production are poorly understood. To evaluate the regulatory roles of quorum-sensing (QS) bacteria in the physiology of Gambierdiscus [...] Read more.
Gambierdiscus spp. are the major culprit responsible for global ciguatera fish poisoning (CFP). At present, the effects of microbiological factors on algal proliferation and toxin production are poorly understood. To evaluate the regulatory roles of quorum-sensing (QS) bacteria in the physiology of Gambierdiscus, co-culture experiments with screened QS strains were conducted in this study. Except for the growth-inhibiting effect from the strain Marinobacter hydrocarbonoclasticus, the algal host generally displayed much higher growth potential and toxin production ability with the existence of QS strains. In addition, Bacillus anthracis particularly exhibited a broad-spectrum growth enhancement effect on various Gambierdiscus types, as well as a remarkable influence on algal toxicity. The variations of algal physiological status, including growth rate, chlorophyll content, and responsive behaviors, are potential reasons for the observed positive or negative affection. This study suggests that QS bacteria regulate the algal growth and toxin production. Based on the evidence, we further speculate that QS bacteria may contribute to the site-specific distribution of CFP risk through regulating the algal host biomass and toxicity. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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Open AccessArticle
A Novel ShK-Like Toxic Peptide from the Transcriptome of the Cnidarian Palythoa caribaeorum Displays Neuroprotection and Cardioprotection in Zebrafish
Received: 17 May 2018 / Revised: 7 June 2018 / Accepted: 8 June 2018 / Published: 12 June 2018
Cited by 2 | PDF Full-text (2801 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Palythoa caribaeorum (class Anthozoa) is a zoantharian which, together with other cnidarians, like jellyfishes, hydra, and sea anemones, possesses specialized structures in its tissues, the cnidocytes, which deliver an array of toxins in order to capture prey and deter predators. The whole transcriptome [...] Read more.
Palythoa caribaeorum (class Anthozoa) is a zoantharian which, together with other cnidarians, like jellyfishes, hydra, and sea anemones, possesses specialized structures in its tissues, the cnidocytes, which deliver an array of toxins in order to capture prey and deter predators. The whole transcriptome of P. caribaeroum was deep sequenced, and a diversity of toxin-related peptide sequences were identified, and some retrieved for functional analysis. In this work, a peptide precursor containing a ShK domain, named PcShK3, was analyzed by means of computational processing, comprising structural phylogenetic analysis, model prediction, and dynamics simulation of peptide-receptor interaction. The combined data indicated that PcShK3 is a distinct peptide which is homologous to a cluster of peptides belonging to the ShK toxin family. In vivo, PcShK3 distributed across the vitelline membrane and accumulated in the yolk sac stripe of zebrafish larvae. Notably, it displayed a significant cardio-protective effect in zebrafish in concentrations inferior to the IC50 (<43.53 ± 6.45 µM), while in high concentrations (>IC50), it accumulated in the blood and caused pericardial edema, being cardiotoxic to zebrafish larvae. Remarkably, PcShK3 suppressed the 6-OHDA-induced neurotoxicity on the locomotive behavior of zebrafish. The present results indicated that PcShK3 is a novel member of ShK toxin family, and has the intrinsic ability to induce neuro- and cardio-protective effects or cause cardiac toxicity, according to its effective concentration. Full article
(This article belongs to the Special Issue Emerging Marine Biotoxins)
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