Publications by authors named "Rosa Figueroa"

Article Synopsis
  • Harmful algal blooms (HABs), especially those from toxin-producing microalgae like Prorocentrum micans, are a recurring issue in Patagonian fjords, and a significant HB-HAB occurred in Northwest Chilean Patagonia during February-March 2022.
  • Observations showed a dramatic increase in P. micans cell density from low levels in January to a peak of over 8.3 x 10 cells/mL by mid-February, associated with warmer sea temperatures and varying salinity.
  • Satellite images and oceanographic modeling revealed that water currents and temperature variations in the Gulf of Ancud supported the development and maintenance of this harmful algal bloom, indicating a hotspot for both HABs and HB-HAB
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Article Synopsis
  • There has been a global increase in Harmful Algae Blooms (HABs) over recent decades, linked to environmental exploitation, enhanced monitoring, and rising maritime transport.
  • HAB species, such as those causing paralytic shellfish poisoning and producing yessotoxins, pose serious public health and socioeconomic risks.
  • Recent observations in the Biobio region suggest a northward movement of these HABs into more open waters, with studies indicating that factors like deep-water turbulence and the presence of toxic resting cysts could trigger harmful events in the environment.
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In late summer and early autumn 2022, an intense bloom of Protoceratium reticulatum-the main yessotoxin (YTX) producer along Chilean coasts and a major threat to artisanal fisheries, the aquaculture industry, and environmental health-was recorded in the Patagonian fjord system. The high YTX levels (>3.75 mg kg) resulted in the first ban of shellfish collection in Chile.

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The changes in the cell physiology (growth rate, cell size, and cell DNA content), photosynthetic efficiency, toxicity, and sexuality under variable light and nutrient (phosphates) conditions were evaluated in cultures of the dinoflagellate obtained from a red tide in the Ría de Vigo (NW Spain). The cells were grown at low (40 and 150 µE m s), moderate (400 µE m s), and high (800 µE m s) light intensities in a medium with phosphate (P+) and without (P-). Cultures were acclimated to the irradiance conditions for one week, and the experiment was run for ~1 month.

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Protoceratium reticulatum is the main yessotoxin-producer along the Chilean coast. Thus far, the yessotoxin levels recorded in this region have not posed a serious threat to human health. However, a bloom of P.

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Introduction: The rise of new technologies in the field of health is yielding promising results. In certain chronic conditions such as type 2 diabetes mellitus, which ranks among the top five causes of global mortality, it could be useful in supporting patient management.

Materials And Methods: A systematic review will be conducted on scientific publications from the last 5 years (January 2019 to October 2023) to describe the effect of mobile app usage on glycated hemoglobin for the management of adult patients with type 2 diabetes mellitus who participated in randomized controlled clinical trials.

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Dinoflagellates are known to possess an exceptionally large genome organized in permanently condensed chromosomes. Focusing on the contribution of satellite DNA (satDNA) to the whole DNA content of genomes and its potential role in the architecture of the chromosomes, we present the characterization of the satellitome of Alexandriun minutum strain VGO577. To achieve this, we analyzed Illumina reads using graph-based clustering and performed complementary bioinformatic analyses.

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The frequency of harmful algal blooms (HABs) has increased over the last two decades, a phenomenon enhanced by global climate change. However, the effects of climate change will not be distributed equally, and Chile has emerged as one important, vulnerable area. The Chilean Patagonian region (41‒56°S) hosts two marine ecoregions that support robust blue economies via wild fisheries, aquaculture, and tourism.

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Toxic and harmful algal blooms (HABs) are a global problem affecting human health, marine ecosystems, and coastal economies, the latter through their impact on aquaculture, fisheries, and tourism. As our knowledge and the techniques to study HABs advance, so do international monitoring efforts, which have led to a large increase in the total number of reported cases. However, in addition to increased detections, environmental factors associated with global change, mainly high nutrient levels and warming temperatures, are responsible for the increased occurrence, persistence, and geographical expansion of HABs.

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Article Synopsis
  • This study examines how changes in climate and ocean conditions affect phytoplankton populations in the Patagonian Fjord System, specifically focusing on a toxic phytoplankton succession.
  • It highlights a significant shift from the dinoflagellate Dinophysis acuta to the diatom Pseudo-nitzschia calliantha due to a strong atmospheric river's influence, particularly during late summer and early autumn.
  • The research also marks the first documented occurrence of the toxic P. calliantha in Northern Patagonia and discusses the potential consequences of its biotoxins on local marine ecosystems.
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Article Synopsis
  • * In March 2021, H. akashiwo caused heavy salmon mortality in Comau Fjord, with nearly 6000 tons of biomass lost in just 15 days, driven by a bloom reaching extremely high cell densities.
  • * Environmental factors, including high-pressure systems, dry conditions, and local hydrodynamics in the fjord, played a crucial role in the development and intensity of this harmful algal bloom.
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Article Synopsis
  • Harmful algal blooms, particularly from dinoflagellates causing paralytic shellfish poisoning (PSP), negatively impact shellfish harvests and lead to socio-economic challenges.
  • A study in southern Chile analyzed the PSP toxicity in clams across two fishing locations, revealing intense toxic blooms during the summer of 2009, with significant spatial and temporal variability in toxicity levels and detoxification rates.
  • Findings suggest that understanding the variability in PSP toxicity at different scales is crucial for better fisheries management and to mitigate the effects of toxic events on shellfish populations.
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Article Synopsis
  • - Harmful Algal Blooms (HAB), particularly those caused by the dinoflagellate Alexandrium catenella, produce saxitoxins that lead to serious human health issues like Paralytic Shellfish Poisoning (PSP).
  • - Most research in the Chilean Patagonia has focused on coastal regions, overlooking the potential role of the offshore continental shelf as a source of A. catenella resting cysts that could trigger toxic blooms.
  • - The study reveals that submarine canyons enhance coastal upwelling by increasing the vertical movement of bottom waters, which increases the risk of reintroducing A. catenella cysts into thriving regions for harmful blooms.
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Harmful algal blooms (HABs) are recurrent in the NW Patagonia fjords system and their frequency has increased over the last few decades. Outbreaks of HAB species such as Alexandrium catenella, a causal agent of paralytic shellfish poisoning, and Protoceratium reticulatum, a yessotoxins producer, have raised considerable concern due to their adverse socioeconomic consequences. Monitoring programs have mainly focused on their planktonic stages, but since these species produce benthic resting cysts, the factors influencing cyst distributions are increasingly gaining recognition as potentially important to HAB recurrence in some regions.

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Dinoflagellates are a group of protists whose exceptionally large genome is organized in permanently condensed nucleosome-less chromosomes. In this study, we examined the potential role of repetitive DNAs in both the structure of dinoflagellate chromosomes and the architecture of the dinoflagellate nucleus. Non-denaturing fluorescent in situ hybridization (ND-FSH) was used to determine the abundance and physical distribution of telomeric DNA and 16 microsatellites (1- to 4-bp repeats) in the nucleus of Gambierdiscus australes.

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The bloom-forming toxic dinoflagellate was first detected in southern Chile (39.5-55° S) 50 years ago and is responsible for most of the area's cases of paralytic shellfish poisoning (PSP). Given the complex life history of , which includes benthic sexual cysts, in this study, we examined the potential link between latitude, toxicity, and sexual compatibility.

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Fish-killing blooms of Heterosigma akashiwo and Pseudochattonella verruculosa have been devastating for the farmed salmon industry, but in Southern Chile the conditions that promote the growth and toxicity of these microalgae are poorly understood. This study examined the effects of different combinations of temperature (12, 15, 18 °C) and salinity (10, 20, 30 psu) on the growth of Chilean strains of these two species. The results showed that the optimal growth conditions for H.

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Benthic dinoflagellates of the genus Gambierdiscus produce ciguatoxins, compounds that when metabolized in fish and consumed by humans cause ciguatera poisoning (CP). This syndrome, which is widespread in tropical and subtropical regions, has recently been reported also in subtropical-temperate latitudes such as the Canary Islands where CP events have been regularly detected since 2004. This study examined the effect of temperature on the growth of Gambierdiscus isolated from Canary waters: G.

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Chromosomal markers of the diversity and evolution of dinoflagellates are scarce because the genomes of these organisms are unique among eukaryotes in terms of their base composition and chromosomal structure. Similarly, a lack of appropriate tools has hindered studies of the chromosomal localization of 5S ribosomal DNA (rDNA) in the nucleosome-less chromosomes of dinoflagellates. In this study, we isolated and cloned 5S rDNA sequences from various toxin-producing species of the genus Alexandrium and developed a fluorescence in situ hybridization (FISH) probe that allows their chromosomal localization.

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A recently published study analyzed the phylogenetic relationship between the genera Centrodinium and Alexandrium, confirming an earlier publication showing the genus Alexandrium as paraphyletic. This most recent manuscript retained the genus Alexandrium, introduced a new genus Episemicolon, resurrected two genera, Gessnerium and Protogonyaulax, and stated that: "The polyphyly [sic] of Alexandrium is solved with the split into four genera". However, these reintroduced taxa were not based on monophyletic groups.

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The dinoflagellate Alexandrium catenella is responsible for paralytic shellfish poisoning and negative socioeconomic impacts on the fishing industry and aquaculture. In Chilean Patagonia, the reasons underlying the significant increase in the geographical extension (from south to north) of A. catenella blooms during the last five decades are not well understood.

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Marine parasites of the genus Parvilucifera have been described as endoparasitoids of dinoflagellates. Recently, the species Parvilucifera corolla was described, but its host range was not examined. Here, the host selectivity of P.

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In this work, we present FREGEX a method for automatically extracting features from biomedical texts based on regular expressions. Using Smith-Waterman and Needleman-Wunsch sequence alignment algorithms, tokens were extracted from biomedical texts and represented by common patterns. Three manually annotated datasets with information on obesity, obesity types, and smoking habits were used to evaluate the effectiveness of the proposed method.

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Scrippsiella is a cosmopolitan dinoflagellate genus that is able to form Harmful Algal Blooms in coastal waters. The large physiological, morphological, and genetic variability that characterizes this genus suggest the existence of cryptic species. In this study, flow cytometric analyses were carried out to compare the cell cycle and life cycle of two Scrippsiella strains from two different species: Scrippsiella ramonii (VGO1053) and Scrippsiella acuminata (S3V).

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Dinoflagellates are a group of protists whose genome is unique among eukaryotes in terms of base composition, chromosomal structure and gene expression. Even after decades of research, the structure and behavior of their amazing chromosomes-which without nucleosomes exist in a liquid crystalline state-are still poorly understood. We used flow cytometry and fluorescence in situ hybridization (FISH) to analyze the genome size of three species of the toxic dinoflagellate genus Karenia as well the organization and behavior of the chromosomes in different cell-cycle stages.

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