AI Article Synopsis
- The study investigates the gene sequences involved in saxitoxin (STX) production in both toxic and non-toxic species of the dinoflagellate Alexandrium.
- Comparative analysis shows that toxic species have a higher similarity in the genes responsible for STX production, while non-toxic species appear to have lost key genes associated with toxicity.
- Phylogenetic analysis indicates that toxic Alexandrium may have acquired its STX genes through horizontal gene transfer from toxic cyanobacteria, suggesting a complex evolutionary history.
Article Abstract
The marine dinoflagellate Alexandrium is known to form harmful algal blooms, and at least 14 species within the genus can produce saxitoxins (STXs). STX biosynthesis genes (sxt) are individually revealed in toxic dinoflagellates; however, the evolutionary history remains controversial. Herein, we determined the transcriptome sequences of toxic Alexandrium (A. catenella and A. pacificum) and non-toxic Alexandrium (A. fraterculus and A. fragae) and characterized their sxt by focusing on evolutionary events and STX production. Comparative transcriptome analysis revealed higher homology of the sxt in toxic Alexandrium than in non-toxic species. Notably, non-toxic Alexandrium spp. were found to have lost two sxt core genes, namely sxtA4 and sxtG. Expression levels of 28 transcripts related to eight sxt core genes showed that sxtA, sxtG, and sxtI were relatively high (>1.5) in the toxic group compared to the non-toxic group. In contrast, the non-toxic group showed high expression levels in sxtU (1.9) and sxtD (1.7). Phylogenetic tree comparisons revealed distinct evolutionary patterns between 28S rDNA and sxtA, sxtB, sxtI, sxtD, and sxtU. However, similar topology was observed between 28S rDNA, sxtS, and sxtH/T. In the sxtB and sxtI phylogeny trees, toxic Alexandrium and cyanobacteria were clustered together, separating from non-toxic species. These suggest that Alexandrium may acquire sxt genes independently via horizontal gene transfer from toxic cyanobacteria and other multiple sources, demonstrating monocistronic transcripts of sxt in dinoflagellates.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1016/j.hal.2024.102620 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The development of rapid detection techniques for Alexandrium catenella.
Environ Sci Pollut Res Int
January 2025
College of the Environment and Ecology, Xiamen University, Xiamen, 361102, Fujian, People's Republic of China.
Alexandrium catenella is an important toxic algal species in the Alexandrium genus, which can form toxic red tides in large numbers. The paralytic shellfish poisoning (PSP) produced by Alexandrium catenella can seriously endanger human health and threaten the production and development of the aquaculture and fishery industries. Therefore, it is important to explore and develop effective detection and early warning methods for toxic red tides.
View Article and Find Full Text PDFThe DnaJ-Hsp70-Hsp90 co-chaperon networks in scallops under toxic Alexandrium dinoflagellates exposure.
Ecotoxicol Environ Saf
January 2025
MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences (Qingdao 266003), and Key Laboratory of Tropical Aquatic Germplasm of Hainan Province, Sanya Oceanographic Institution (Sanya 572024), Ocean University of China, China. Electronic address:
Heat shock proteins (Hsps) are highly conserved molecular chaperones with essential roles against biotic and abiotic stressors. A large set of co-chaperons comprising J-domain proteins (DnaJs) regulate the ATPase cycle of Hsp70s with Hsp90s, together constituting a dynamic and functionally versatile network for protein folding/unfolding and regulation. Marine bivalves could accumulate and tolerate paralytic shellfish toxins (PSTs), the well-noted neurotoxins generated during harmful algal blooms.
View Article and Find Full Text PDFSublethal exposure of eastern oyster Crassostrea virginica to the goniodomin-producing dinoflagellate Alexandrium monilatum: Fate of toxins, histopathology, and gene expression.
J Aquat Anim Health
December 2024
Virginia Institute of Marine Science, William & Mary, Gloucester Point, Virginia, USA.
Objective: The dinoflagellate Alexandrium monilatum forms blooms during summer in tributaries of the lower Chesapeake Bay. Questions persist about the potential for A. monilatum to negatively affect aquatic organisms.
View Article and Find Full Text PDFToxin production in bloom-forming, harmful alga Alexandrium pacificum (Group IV) is regulated by cyst formation-promoting bacteria Jannaschia cystaugens NBRC 100362.
Water Res
December 2024
Biological Resource Center/Korean Collection for Type Cultures (KCTC), Korea Research Institute of Bioscience and Biotechnology, Jeongeup 56212, Republic of Korea; Department of Environmental Biotechnology, KRIBB School of Biotechnology, University of Science and Technology (UST), Daejeon 34113, Republic of Korea. Electronic address:
Harmful algal blooms (HABs) caused by dinoflagellates like Alexandrium pacificum pose significant ecological and public health risks due to their production of paralytic shellfish toxins (PSTs). Bacterial populations, particularly Alexandrium cyst formation-promoting bacteria (Alex-CFPB), are known to significantly influence growth, encystment, toxin synthesis, the composition of toxic components, and bloom dynamics of these dinoflagellates. However, the role of Alex-CFPB in Alexandrium toxin synthesis and the mechanisms thereof are still unclear.
View Article and Find Full Text PDFAssessment of dinoflagellate diversity using DNA metabarcoding reveals toxic dinoflagellate species in Australian coastal waters.
Mar Pollut Bull
January 2025
Centre for Sustainable Tropical Fisheries and Aquaculture, James Cook University, Townsville, Qld 4811, Australia; College of Science and Engineering, James Cook University, Townsville, Qld 4811, Australia.
Article Synopsis
- - The study focuses on understanding harmful algal blooms (HABs), especially dinoflagellates, in Hervey Bay, Queensland, which is prone to these ecological threats.
- - Utilizing DNA metabarcoding, researchers identified 66 different dinoflagellate genera, including several known toxic species like Alexandrium and Gambierdiscus, some of which were newly recorded in Australia.
- - The research highlights the need for continuous monitoring of these harmful species and the environmental factors affecting their abundance to protect marine ecosystems and public health in vulnerable coastal areas.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!