Article
Food Science & Technology
Michael J. Holmes, Richard J. Lewis
Summary: By modeling a marine food chain in Platypus Bay, Australia, we aimed to understand the impact of food chain dynamics on ciguatera risk. Due to limited data, the estimates from this simulation were rough, but it highlighted the need for better quantitative estimates to improve our understanding and management of ciguatera risk.
Article
Environmental Sciences
Luciana Tartaglione, Christopher R. Loeffler, Valentina Miele, Fabio Varriale, Michela Varra, Marcello Monti, Alessia Varone, Dorina Bodi, Astrid Spielmeyer, Samuela Capellacci, Antonella Penna, Carmela Dell'Aversanoa
Summary: Marine toxins have a significant impact on seafood resources and human health. This study focused on screening and identifying bioactive compounds produced by Gambierdiscus balechii, a toxic microalgae species, using liquid chromatography-high resolution mass spectrometry and in vitro cell-based bioassays. The study identified CTX-like and MTX-like toxicity in fractions of the algal extract, and confirmed the presence of a putative I/C-CTX congener. This research has important implications for understanding ciguatera poisoning and developing analytical methods for its detection.
Article
Marine & Freshwater Biology
Kathleen J. Pitz, Mindy L. Richlen, Evangeline Fachon, Tyler B. Smith, Michael L. Parsons, Donald M. Anderson
Summary: Ciguatera poisoning (CP) is caused by the accumulation of lipophilic ciguatoxins in coral reef fish and invertebrates, produced by Gambierdiscus spp. Recent studies have identified diverse species within the Gambierdiscus genus, prompting the development of new tools for species identification and enumeration. Fluorescence in situ hybridization (FISH) probes were designed for seven species, allowing for accurate determination of community composition and cell abundances. The application of species-specific FISH probes provides a powerful new tool to target individual Gambierdiscus species in field populations, aiding in understanding and managing the risks of CP worldwide.
Article
Food Science & Technology
Michael J. Holmes, Richard J. Lewis
Summary: Cells in a clonal culture of the WC1/1 strain of Gambierdiscus were observed to spontaneously fuse during growth, with the fusion process involving the formation of protrusions and fusion with other cells. Cell size in the clonal culture displayed a bimodal distribution.
Article
Engineering, Marine
Naomasa Oshiro, Hiroya Nagasawa, Mio Nishimura, Kyoko Kuniyoshi, Naoki Kobayashi, Yoshiko Sugita-Konishi, Tsuyoshi Ikehara, Katsunori Tachihara, Takeshi Yasumoto
Summary: Ciguatera fish poisoning (CFP) is caused by consuming fish with accumulated ciguatoxins (CTXs). The risk of consuming the grouper Variola albimarginata in Okinawa is considered to be low. Only a few fish had CTX levels that exceeded the Japanese recommendation, compared to the US FDA guidance level.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Review
Food Science & Technology
Michael J. Holmes, Bill Venables, Richard J. Lewis
Summary: The study suggests that Gambierdiscus and Fukuyoa species growing on turf algae may be the main source of ciguatoxins entering marine food chains in the Platypus Bay and Great Barrier Reef regions. Herbivorous fish, specifically surgeonfish, may act as a feedback mechanism to control the flow of ciguatoxins in the marine food chain. Overharvesting of herbivores could lead to an increase in ciguatera, while fish somatic growth may only reduce toxin levels in certain scenarios.
Article
Environmental Sciences
Elizabeth M. Mudge, Christopher O. Miles, Lada Ivanova, Silvio Uhlig, Keiana S. James, Deana L. Erdner, Christiane K. Faeste, Pearse McCarron, Alison Robertson
Summary: A novel ciguatoxin analogue, C-CTX5, was identified from two species of Gambierdiscus algae in the Caribbean, and it was found to be converted into the dominant toxin, CTX1/2, in ciguatoxic fish. This discovery is crucial for risk assessment, understanding the fate of C-CTXs in food webs, and developing effective analytical methods and monitoring programs.
Article
Food Science & Technology
Naomasa Oshiro, Hiroya Nagasawa, Kyoko Kuniyoshi, Naoki Kobayashi, Yoshiko Sugita-Konishi, Hiroshi Asakura, Takeshi Yasumoto
Summary: Ciguatera fish poisoning is a common seafood poisoning syndrome caused by consuming marine finfish contaminated with ciguatoxins, with traditional beliefs about the toxicity of fish heads and viscera lacking scientific support. Analyzing tissue samples from yellow-edged lyretail individuals, the study found ciguatoxins distributed evenly in flesh, supporting the conclusion that samples for analysis can be taken from any part of the body. Interestingly, the study also demonstrated significantly higher levels of toxins in the tissue surrounding the eyeball, providing scientific evidence of their high toxicity.
Article
Ecology
Ana Sofia Guerra, Jacey C. Van Wert, Alison J. Haupt, Douglas J. McCauley, Erika J. Eliason, Hillary S. Young, David Lecchini, Timothy D. White, Jennifer E. Caselle
Summary: Variation in behavior within marine and terrestrial species can influence ecosystem function. However, the contribution of social behavior to ecosystem function remains underexplored. Using behavioral observations, stable isotope analysis, and macronutrient analysis, this study examines the ecological function differences between shoaling and solitary surgeonfish in Pacific coral reefs. The results show significant differences in spatial and feeding ecology between the two social modes, indicating that social behavior plays an important role in mediating ecological function.
ECOLOGY AND EVOLUTION
(2023)
Article
Food Science & Technology
Justin D. Liefer, Mindy L. Richlen, Tyler B. Smith, Jennifer L. DeBose, Yixiao Xu, Donald M. Anderson, Alison Robertson
Summary: The peak abundance of Gambierdiscus spp. occurred in summer while CTX-specific toxicity peaked in cooler months, showing an asynchronous relationship. This may reflect differences in toxin cell quotas among Gambierdiscus species.
Article
Biology
H. B. Harrison, L. Drane, M. L. Berumen, B. J. Cresswell, R. D. Evans, G. F. Galbraith, M. Srinivasan, B. M. Taylor, D. H. Williamson, G. P. Jones
Summary: Temporal patterns in spawning and juvenile recruitment of coral reef fishes have significant impacts on population size and demographic structure. The study focuses on the commercially important coral grouper and reveals year-round spawning activity with variable peak spawning times and no clear association with environmental cues. The findings suggest the need for additional and longer seasonal closures or alternative fisheries management strategies to maximize recruitment contribution during periods of greatest reproductive success.
PROCEEDINGS OF THE ROYAL SOCIETY B-BIOLOGICAL SCIENCES
(2023)
Review
Environmental Sciences
Christopher R. Loeffler, Luciana Tartaglione, Miriam Friedemann, Astrid Spielmeyer, Oliver Kappenstein, Dorina Bodi
Summary: Global marine ecosystem changes impact the livelihoods of over a billion people, with ciguatera poisoning being a major threat. Small island nations face extreme food insecurity, while anthropogenic or natural changes in global marine habitats exacerbate complexities.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH
(2021)
Article
Fisheries
Xiaomei Dou, Yu Liu, Yixiong Cao, Yumeng Zhang, Xinlangji Fu, Junming Deng, Beiping Tan
Summary: An 8-week feeding trial showed that an appropriate dietary lysine level improved the growth performance and protein metabolism of juvenile leopard coral grouper. The optimal lysine requirement for growth and lysine deposition was found to be 2.60%-2.97% of diets (4.91%-5.60% of dietary protein).
AQUACULTURE NUTRITION
(2023)
Article
Fisheries
Morgan S. Pratchett, Ciemon F. Caballes, Jean-Paul A. Hobbs, Joseph D. DiBattista, Brock Bergseth, Peter Waldie, Curtis Champion, Samuel P. Mc Cormack, Andrew S. Hoey
Summary: This study explored the variation in physiological condition of common coral trout on Australia's Great Barrier Reef after severe mass bleaching and coral loss. The results showed that fish condition was largely influenced by fish size and varied with latitude, while there was no apparent effect of recent coral bleaching on the physiological condition of the fish. However, further changes to the environmental conditions and reef habitat may impact these important fisheries species.
Article
Chemistry, Medicinal
Fabio Begnini, Stefan Geschwindner, Patrik Johansson, Lisa Wissler, Richard J. Lewis, Emma Danelius, Andreas Luttens, Pierre Matricon, Jens Carlsson, Stijn Lenders, Beate Konig, Anna Friedel, Peter Sjoe, Stefan Schiesser, Jan Kihlberg
Summary: Upregulation of the transcription factor Nrf2 by inhibiting the interaction with Keap1, its negative regulator, presents an opportunity for treating diseases caused by oxidative stress. In this study, we report the discovery of nanomolar Keap1 inhibitors derived from a natural product, which showed a 100-fold increase in inhibitory potency through structure-guided optimization. The nanomolar inhibitors positioned three pharmacophore units for productive interactions with Keap1, leading to significant changes in the thermodynamic profile. Optimizing the ligand resulted in displacement of a water molecule from the Keap1 binding site and alterations in the affinity between ligands, demonstrating the importance of considering hydration and flexibility of the Keap1 binding site when designing high-affinity ligands.
JOURNAL OF MEDICINAL CHEMISTRY
(2022)
Article
Biochemistry & Molecular Biology
Patrick Wilhelm, Karen Luna-Ramirez, Yanni K. -Y. Chin, Zoltan Dekan, Nikita Abraham, Han-Shen Tae, Chun Yuen Chow, David A. Eagles, Glenn F. King, Richard J. Lewis, David J. Adams, Paul F. Alewood
Summary: In this study, the researchers discovered that alpha-SII is a unique toxin in the alpha-Conotoxin family, with a distinct structure and mechanism of action. It exhibits potent inhibitory effects on muscle nAChRs, but weak activity on neuronal nAChRs. Truncation and alteration of its disulfide bond connectivity did not significantly alter its activity.
ACS CHEMICAL NEUROSCIENCE
(2022)
Article
Chemistry, Medicinal
S. W. A. Himaya, Alexander Arkhipov, Wai Ying Yum, Richard J. Lewis
Summary: In this study, scientists found that the venom biodiversity of Cone snails reflects their dietary preference and predatory and defensive envenomation strategies. By investigating the venom of two closely related species, C. flavidus and C. frigidus, they discovered differences in conotoxin transcripts, which may have facilitated the evolution of new species.
Article
Biochemistry & Molecular Biology
Fernanda C. Cardoso, Sandy S. Pineda, Volker Herzig, Kartik Sunagar, Naeem Yusuf Shaikh, Ai-Hua Jin, Glenn F. King, Paul F. Alewood, Richard J. Lewis, Sebastien Dutertre
Summary: Australian tree-dwelling funnel-web spiders have venom that induces deadly symptoms and exhibits different venom composition compared to ground-dwelling species. The venom of tree-dwellers strongly modulates human voltage-gated sodium and calcium channels, while also showing potent insecticidal effects. This study contributes to understanding the molecular and pharmacological basis for severe envenomation by Australian tree-dwelling funnel-web spiders.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Anesthesiology
Luke Grundy, Cindy Tay, Stewart Christie, Andrea M. M. Harrington, Joel Castro, Fernanda C. C. Cardoso, Richard J. J. Lewis, Vladimir Zagorodnyuk, Stuart M. M. Brierley
Summary: The bladder wall is innervated by a complex network of afferent nerves that detect bladder stretch during filling. Low-voltage-activated T-type calcium channels play a major role in regulating bladder afferent responses to distension.
Article
Food Science & Technology
Michael J. Holmes, Richard J. Lewis
Summary: Cells in a clonal culture of the WC1/1 strain of Gambierdiscus were observed to spontaneously fuse during growth, with the fusion process involving the formation of protrusions and fusion with other cells. Cell size in the clonal culture displayed a bimodal distribution.
Article
Multidisciplinary Sciences
Aymeric Rogalski, S. W. A. Himaya, Richard J. Lewis
Summary: This study documents the culture of Conus magus and reveals dramatic shifts in predatory feeding behavior between post-metamorphic juveniles and adult specimens. The research found that early juveniles exclusively feed on polychaete worms using a unique sting-and-stalk foraging behavior, while adults capture fish using venom peptides and a hooked radular tooth.
NATURE COMMUNICATIONS
(2023)
Article
Pharmacology & Pharmacy
Thao N. T. Ho, Nikita Abraham, Richard J. Lewis
Summary: This study describes the allosteric binding mode of the granulin-like C-terminal (CTD) of VxXXB bound to Lymnea stagnalis acetylcholine binding protein (Ls-AChBP), revealing a novel allosteric binding site for nAChR antagonists. The results provide new structural insight into the allosteric mechanism of nAChR inhibition and define the cooperative binding mode of aD-conotoxins' N-terminal domain linked granulin core domains.
FRONTIERS IN PHARMACOLOGY
(2023)
Article
Chemistry, Medicinal
Edin Muratspahic, Andrew M. White, Cosmin I. Ciotu, Nadine Hochrainer, Natasa Tomasevic, Johannes Koehbach, Richard J. Lewis, Mariana Spetea, Michael J. M. Fischer, David J. Craik, Christian W. Gruber
Summary: This study developed a novel KOR antagonist using peptide stapling and demonstrated its high selectivity and competitive antagonistic effect. The findings provide valuable insights for the development of innovative peptide drugs for KOR-related illnesses.
JOURNAL OF MEDICINAL CHEMISTRY
(2023)
Review
Food Science & Technology
Ivannah Pottier, Richard J. Lewis, Jean-Paul Vernoux
Summary: Ciguatera is a widespread poisoning caused by eating marine fish and invertebrates contaminated with ciguatoxins. The various types of ciguatoxins and their properties have been studied extensively, but there is no standardized method for extracting and quantifying ciguatoxins due to limited reference materials. Recent advances in analysis techniques offer new opportunities for detecting and quantifying ciguatoxins, but further research is needed to understand their toxicity and role in ciguatera fish poisoning.
Article
Pharmacology & Pharmacy
Yashad Dongol, David T. Wilson, Norelle L. Daly, Fernanda C. Cardoso, Richard J. Lewis
Summary: Structure-function and optimization studies of NaV-inhibiting spider toxins have been conducted to develop selective inhibitors for NaV1.7. This study extends the understanding of the structure-function relationships to include other NaV subtypes, NaV1.2 and NaV1.3. Analogues were designed for improved potency and/or subtype-selectivity, with S7R-E18K-rSsp1a and N14D-P27R-rSsp1a identified as promising leads. The findings highlight the challenge of developing subtype-selective spider toxin inhibitors across multiple NaV subtypes.
FRONTIERS IN PHARMACOLOGY
(2023)
Article
Chemistry, Medicinal
Edin Muratspahic, Andrew M. White, Cosmin I. Ciotu, Nadine Hochrainer, Natasa Tomasevic, Johannes Koehbach, Richard J. Lewis, Mariana Spetea, Michael J. M. Fischer, David J. Craik, Christian W. Gruber
Summary: In this study, a stable and potent KOR antagonist was developed using cysteine functionalization. The antagonist showed improved selectivity for KOR, and its effectiveness was verified in various cell lines and animal models. This research highlights the value of cysteine stapling in the development of KOR-related drugs.
JOURNAL OF MEDICINAL CHEMISTRY
(2023)
Article
Biochemistry & Molecular Biology
Thao N. T. Ho, Nikita Abraham, Richard J. Lewis
Summary: This study focused on the synthesis and characterization of the C-terminal domain (CTD) and N-terminal domain (NTD) of alpha D-Conotoxin VxXXB. The CTD showed potent inhibition of alpha 7 nAChRs and displayed allosteric binding to Ls-AChBP. The regioselective synthesis of the anti-parallel dimeric NTD also resulted in inhibition of alpha 7 nAChRs, although with reduced potency.
RSC MEDICINAL CHEMISTRY
(2022)
Article
Biochemistry & Molecular Biology
Fernanda C. Cardoso, Matthieu Schmit, Michael J. Kuiper, Richard J. Lewis, Kellie L. Tuck, Peter J. Duggan
Summary: This study reveals that TCAs may inhibit neuropathic pain by interfering with the conformation of endogenous Ca(V)2.2 channels, providing the most comprehensive evidence to date supporting the notion that TCAs exert their analgesic effect through blocking calcium ion channels.
RSC MEDICINAL CHEMISTRY
(2022)