Okadaic acid (OA), dinophysistoxin (DTX), and their analogous polyketide compounds, produced by P. lima, are the toxins responsible for diarrhetic shellfish poisoning (DSP). Understanding the molecular mechanism of DSP toxin biosynthesis is paramount for comprehending the environmental drivers influencing toxin production, as well as for better monitoring of marine ecosystems. Polyketides' biosynthesis is often catalyzed by the enzymatic machinery of polyketide synthases, or PKS. Despite this, no gene has been conclusively identified as responsible for creating DSP toxins. From the 94,730,858 Illumina RNA-Seq reads, Trinity assembled a transcriptome containing 147,527 unigenes, with an average nucleotide sequence length of 1035. By employing bioinformatics methods, we determined 210 unigenes encoding single-domain polyketide synthases (PKS) with sequence homology to type I PKSs, matching the results found in studies of other dinoflagellate species. The analysis further revealed fifteen transcripts encoding multi-domain PKS (forming the canonical type I PKS modules) and five transcripts encoding hybrid nonribosomal peptide synthetase/polyketide synthase systems. Comparative analysis of transcriptomes, coupled with differential expression profiling, revealed 16 PKS genes upregulated in phosphorus-limited cultures, a phenomenon related to upregulation of toxin production. This study, in line with other recent transcriptome analyses, reinforces the developing understanding that dinoflagellates potentially synthesize polyketides utilizing a combination of Type I multi-domain and single-domain PKS proteins, via a method that remains to be defined. Selleckchem BMS-986235 Future researchers interested in deciphering the complex toxin production mechanisms in this dinoflagellate will find our study's genomic resource to be a valuable asset.

Eleven perkinsozoan parasitoid species that infect dinoflagellates have been identified in the last twenty years, marking a significant increase. Currently, a substantial portion of our knowledge about the autecology of perkinsozoan parasitoids that prey on dinoflagellates is based on the study of only one or two species, which poses a challenge for directly contrasting their biological traits and assessing their suitability as biological control agents in mitigating harmful dinoflagellate blooms. A study examined the total time of generation, the zoospore count per sporangium, zoospore measurement, swimming velocity, prevalence of parasitism, zoospore survivability and success rate, and the range of hosts and their susceptibility to five perkinsozoan parasitoids. Four species from the Parviluciferaceae family—Dinovorax pyriformis, Tuberlatum coatsi, Parvilucifera infectans, and P. multicavata—and one from the Pararosariidae family, Pararosarium dinoexitiosum, shared the dinoflagellate Alexandrium pacificum as a common host. Marked distinctions in the biological attributes of the five perkinsozoan parasitoid species were discovered, implying differing degrees of adaptability to the particular host organism. The outcomes presented here provide essential context for understanding the impact of parasitoids on host populations, as well as for constructing numerical models inclusive of host-parasitoid interactions and guiding field-based biocontrol research.

The marine microbial community likely employs extracellular vesicles (EVs) as a vital method of transport and intercellular communication. The task of isolating and characterizing axenic cultures of microbial eukaryotes presents an ongoing technological challenge. Our investigation successfully isolated extracellular vesicles (EVs) from a near-axenic culture of the harmful dinoflagellate Alexandrium minutum for the first time. Cryo TEM (Cryogenic Transmission Electron Microscopy) provided images of the isolated vesicles. Based on their morphological characteristics, the EVs were grouped into five primary categories (rounded, electron-dense rounded, electron-dense lumen, double-layered, and irregular), and a measurement of each EV's size produced a mean diameter of 0.36 micrometers. Due to the proven influence of extracellular vesicles (EVs) on the toxicity processes in prokaryotes, this descriptive study seeks to establish a baseline for the exploration of EVs' potential role in the toxicity of dinoflagellates.

Recurring blooms of Karenia brevis, commonly called red tide, pose a persistent threat to the coastal waters of the Gulf of Mexico. These flowers hold the ability to inflict considerable harm upon human and animal health, in addition to local economies. Hence, the surveillance and detection of K. brevis blooms, from their inception to maturity and across a range of cell counts, are critical for community well-being. Auto-immune disease Current K. brevis monitoring methodologies suffer from limitations in size resolution and concentration ranges, alongside circumscribed capabilities for spatial and temporal analysis, and/or small sample volume processing difficulties. A novel method for monitoring is described, featuring an autonomous digital holographic imaging microscope (AUTOHOLO). This advancement overcomes current limitations, enabling the in-situ characterization of K. brevis concentrations. Field measurements, utilizing the AUTOHOLO, were undertaken in situ during a K. brevis bloom within the coastal Gulf of Mexico, encompassing the winter months of 2020-2021. The validation of surface and subsurface water samples, collected during these field studies, involved laboratory procedures using benchtop holographic imaging and flow cytometry. By training a convolutional neural network, automated classification of K. brevis was accomplished, spanning all concentration levels. Across datasets with fluctuating K. brevis concentrations, the network's accuracy was 90%, validated through manual counts and flow cytometry. The AUTOHOLO, when integrated with a towing system, was shown to be effective in characterizing particle abundance across significant distances, a technique that could aid in the characterization of K. brevis spatial distribution during blooms. In aquatic environments around the world, future enhancements to K. brevis detection are possible through the integration of AUTOHOLO into existing HAB monitoring networks.

The specific way in which seaweeds react to environmental stressors depends on their population and the conditions of their habitat regime. The growth and physiological responses of Ulva prolifera, specifically two strains (Korean and Chinese), were examined under various conditions of temperature (20°C and 25°C), nutrient levels (low: 50 µM nitrate and 5 µM phosphate; high: 500 µM nitrate and 50 µM phosphate), and salinity (20, 30, and 40 parts per thousand). At 40 psu of salinity, both strains exhibited the lowest growth rates, uninfluenced by variations in temperature or nutrient levels. In the Chinese strain, the carbon-nitrogen (C:N) ratio increased by 311% and the growth rate by 211% at 20°C and low nutrient conditions with a salinity of 20 psu, relative to 30 psu salinity. Both strains saw a decrease in their CN ratio in response to high nutrient levels, coupled with rising tissue nitrogen content. At a salinity of 20°C, simultaneous high nutrient levels led to increased soluble protein and pigment content, and also accelerated photosynthetic and growth rates in both strains. At temperatures below 20 degrees Celsius and in the presence of abundant nutrients, both strains exhibited a considerable reduction in growth rates and carbon-to-nitrogen ratios as salinity increased. biomass processing technologies The growth rate, under all conditions, displayed an inverse pattern with the pigment, the soluble protein, and tissue N. Furthermore, a 25-degree Celsius temperature inhibited the development of both strains, irrespective of the nutrient content. The temperature of 25 degrees Celsius caused an increase in tissue N and pigment levels in the Chinese strain, but only under conditions of limited nutrients. In both strains, high nutrient levels at 25°C triggered a rise in tissue nitrogen and pigment contents across the range of salinity conditions relative to the 20°C and high nutrient treatment. A 25°C temperature and ample nutrients hindered the growth rate of the Chinese strain across two salinity levels—30 psu and 40 psu—in comparison to the growth rate observed under the influence of 20°C and low nutrient levels at the same salinities. These results highlight a greater susceptibility to hypo-salinity conditions in Ulva blooms caused by the Chinese strain, in comparison to the Korean strain. U. prolifera strains demonstrated enhanced salinity tolerance in response to elevated nutrient levels. U. prolifera blooms of the Chinese strain will experience a reduction at high salt concentrations.

Worldwide, harmful algal blooms (HABs) precipitate widespread fish kills. However, some commercially-sourced fish are perfectly safe to eat. Fish that are safe for consumption present significant differences from the fish that are routinely washed ashore. Existing research highlights the lack of consumer understanding regarding differences in the edibility of various fish, and this is primarily driven by the widely held misperception that certain fish are unhealthy and unsafe. The research into how consumer seafood consumption is influenced by disseminating information regarding the health of seafood during algal blooms is, as of now, limited. A survey was implemented to present respondents with data regarding the health and safety of certain commercially caught seafood, specifically red grouper, during a harmful algal bloom (HAB). This popular, large, deep-sea fish is well-known for its presence in the deep ocean. Compared to those who didn't receive this information, individuals who were given this data were 34 percentage points more inclined to report their intention to consume red grouper during a bloom. Information previously acquired indicates that extended outreach initiatives are likely more effective than promotional campaigns focused solely on the point of sale. The results underscored the importance of having precise knowledge and awareness regarding HABs, which is indispensable for efforts aimed at securing local economies that are dependent on seafood harvesting and consumption.