On the uniformization of L-valued frames

This note discusses the appropriate way of uniformizing the notion of an L-valued frame introduced by A. Pultr and S. Rodabaugh in [Lattice-valued frames, functor categories, and classes of sober spaces, Chapter 6 of Topological and Algebraic Structures in Fuzzy Sets: A Handbook of Recent Developments in the Mathematics of Fuzzy Sets, Kluwer, 2003]. It covers the case of a completely distributive lattice L (which is, in a certain sense, the most general one) and studies the corresponding category of uniform L-valued frames

Salinity-Growth Response and Ichthyotoxic Potency of the Chilean Pseudochattonella verruculosa

Despite salmon farmers suffering the worst damage from a harmful algal bloom in Chile’s history (US$800M) due to a massive outbreak of the dictyochophyte Pseudochattonella verruculosa in 2016 (∼7000–20,000 cells ml−1), the effect of environmental drivers and the potency of lytic toxins produced by the local clones of this species remain still largely unexplored. Based on the drastic oceanographic anomalies observed in the Chilean fjords during the 2016-El Niño “Godzilla” event, the role of salinity (15 to 35 psu) on Pseudochattonella cell growth and cytotoxicity was studied by culturing, scanning electron microscopy (SEM) and using a rainbow trout cell line RTgill-W1 assay to define: (1) vegetative growth rates, (2) cell taxonomy, (3) ichthyotoxicity of monoclonal cultures at 25 and 35 psu in salinity, (4) differences in toxicity of lysed cells and supernatant at different cell concentrations (from 10 to 100,000 cells ml−1), and (5) temporal stability of lytic compounds. This study formally confirms the presence of P. verruculosa in Chilean waters using the large subunit (LSU) of the nuclear ribosomal RNA gene. The Chilean P. verruculosa ARC498 strain showed maximum cell densities at 30 psu (max. 84,333 ± 4,833 cells ml−1) and maximum growth rates (μmax) at 20 psu (1.44 cells d−1). Cultures at 15 psu showed suppressed maximum cell density (max. 269 ± 71 cell ml−1) but high μmax were recorded at the beginning of the exponential growth (1.31 cells d−1). No significant differences were observed between lysed cells and supernatant treatments in the two salinity levels, suggesting that the most lytic portion is released into the cell-free media instead of remaining cell bound. Cytotoxicity was correlated to cell abundance, reducing gill cell viability down to 80 and 65% compared to controls at 10,000 and 100,000 cells ml−1, respectively. Unexpectedly, lytic compounds from P. verruculosa ARC498 at 35 psu showed to be less toxic than cultures at 25, where a noticeable presence of peripheral mucocysts were observed by SEM. Lytic compounds from in vitro experiments are weakly toxic even at high cell concentrations, highly unstable and rapidly degraded in the light after 5 days of storage at 15°C. Our results point to the important effect of salinity on growth and ichthyotoxic potency of Pseudochattonella species and highlight the need for a deeper insight into the role of mucocysts in fish gill damage, which would provide a greater understanding as to the harmful modes of action of this species

Encapsulation of Phenolic Compounds from a Grape Cane Pilot-Plant Extract in Hydroxypropyl Beta-Cyclodextrin and Maltodextrin by Spray Drying

Grape canes, the main byproducts of the viticulture industry, contain high-value bioactive phenolic compounds, whose application is limited by their instability and poorly solubility in water. Encapsulation in cyclodextrins allows these drawbacks to be overcome. In this work, a grape cane pilot-plant extract (GCPPE) was encapsulated in hydroxypropyl beta-cyclodextrin (HP-β-CD) by a spray-drying technique and the formation of an inclusion complex was confirmed by microscopy and infrared spectroscopy. The phenolic profile of the complex was analyzed by LC-ESI-LTQ-Orbitrap-MS and the encapsulation efficiency of the phenolic compounds was determined. A total of 42 compounds were identified, including stilbenes, flavonoids, and phenolic acids, and a complex of (epi)catechin with β-CD was detected, confirming the interaction between polyphenols and cyclodextrin. The encapsulation efficiency for the total extract was 80.5 ± 1.1%, with restrytisol showing the highest value (97.0 ± 0.6%) and (E)-resveratrol (32.7 ± 2.8%) the lowest value. The antioxidant capacity of the inclusion complex, determined by ORAC-FL, was 5300 ± 472 µmol TE/g DW, which was similar to the value obtained for the unencapsulated extract. This formulation might be used to improve the stability, solubility, and bioavailability of phenolic compounds of the GCPPE for water-soluble food and pharmaceutical applications

On the uniformization of L-valued frames

This note discusses the appropriate way of uniformizing the notion of an L-valued frame introduced by A. Pultr and S. Rodabaugh in [Lattice-valued frames, functor categories, and classes of sober spaces, Chapter 6 of Topological and Algebraic Structures in Fuzzy Sets: A Handbook of Recent Developments in the Mathematics of Fuzzy Sets, Kluwer, 2003]. It covers the case of a completely distributive lattice L (which is, in a certain sense, the most general one) and studies the corresponding category of uniform L-valued frames

Distribution of phycotoxins in Última Esperanza Province during the PROFAN expedition 2019

Harmful Algae Blooms pose an increasing threat to the public health and economic stability of Southern Chile, particularly to the aquaculture industries. This fieldwork performed during the PROFAN expedition from 12th to 22nd November 2019 extends the knowledge on the distribution of marine toxin-producing species in the difficult to access Última Esperanza Province in the Magallanes Region. Paralytic Shellfish Poisoning toxins with high relative abundances of saxitoxin and lipophilic toxins dominated by yessotoxins, pectenotoxins and domoic acid were detected at nearly each sampling station. The respective toxin-producing organisms are mainly from the genus Alexandrium and Dinophysis. Furthermore, the first detection of pinnatoxin-G (PnTx-G) in Chilean waters strongly indicates the presence of the dinoflagellate Vulcanodinium rugosum

Progress in Understanding Algal Bloom-Mediated Fish Kills: The Role of Superoxide Radicals, Phycotoxins and Fatty Acids.

Quantification of the role of reactive oxygen species, phycotoxins and fatty acids in fish toxicity by harmful marine microalgae remains inconclusive. An in vitro fish gill (from rainbow trout Oncorhynchus mykiss) assay was used to simultaneously assess the effect in superoxide dismutase, catalase and lactate dehydrogenase enzymatic activities caused by seven species of ichthyotoxic microalgae (Chattonella marina, Fibrocapsa japonica, Heterosigma akashiwo, Karenia mikimotoi, Alexandrium catenella, Karlodinium veneficum, Prymnesium parvum). Quantification of superoxide production by these algae was also performed. The effect of purified phycotoxins and crude extracts was compared, and the effect of fatty acids is discussed. The raphidophyte Chattonella was the most ichthyotoxic (gill cell viability down to 35%) and also the major producer of superoxide radicals (14 pmol cell-1 hr-1) especially after cell lysis. The raphidophyte Heterosigma and dinoflagellate Alexandrium were the least toxic and had low superoxide production, except when A. catenella was lysed (5.6 pmol cell-1 hr-1). Catalase showed no changes in activity in all the treatments. Superoxide dismutase (SOD) and lactate dehydrogenase exhibited significant activity increases of ≤23% and 51.2% TCC (total cellular content), respectively, after exposure to C. marina, but SOD showed insignificant changes with remaining algal species. A strong relationship between gill cell viability and superoxide production or superoxide dismutase was not observed. Purified brevetoxins PbTx-2 and -3 (from Karenia brevis, LC50 of 22.1 versus 35.2 μg mL-1) and karlotoxin KmTx-2 (from Karlodinium; LC50 = 380 ng mL-1) could almost entirely account for the fish killing activity by those two dinoflagellates. However, the paralytic shellfish toxins (PST) GTX1&4, C1&C2, and STX did not account for Alexandrium ichthyotoxicity. Only aqueous extracts of Alexandrium were cytotoxic (≤65% decrease of viability), whereas crude methanol and acetone extracts of Chattonella, Fibrocapsa, Heterosigma, Karlodinium and Prymnesium decreased cell viability down to 0%. These and our previous findings involving the role of fatty acids confirm that superoxide radicals are only partially involved in ichthyotoxicity and point to a highly variable contribution by other compounds such as lipid peroxidation products (e.g. aldehydes)

Mitigation of Marine Dinoflagellates Using Hydrogen Peroxide (H₂O₂) Increases Toxicity towards Epithelial Gill Cells

Hydrogen peroxide (H2O2) has been shown to efficiently remove toxic microalgae from enclosed ballast waters and brackish lakes. In this study, in vitro experiments were conducted to assess the side effects of mitigating toxic and non-toxic dinoflagellates with H2O2. Five H2O2 concentrations (50 to 1000 ppm) were used to control the cell abundances of the toxic dinoflagellates Alexandrium catenella and Karenia selliformis and the non-toxic dinoflagellates Lepidodinium chlorophorum and Prorocentrum micans. Photosynthetic efficiency and staining dye measurements showed the high efficiency of H2O2 for mitigating all dinoflagellate species at only 50 ppm. In a bioassay carried out to test cytotoxicity using the cell line RTgill-W1, control experiments (only H2O2) showed cytotoxicity in a concentration- and time- (0 to 24 h) dependent manner. The toxic dinoflagellates, especially K. selliformis, showed basal cytotoxicity that increased with the application of hydrogen peroxide. Unexpectedly, the application of a low H2O2 concentration increased toxicity, even when mitigating non-toxic dinoflagellates. This study suggests that the fatty acid composition of toxic and non-toxic dinoflagellate species can yield toxic aldehyde cocktails after lipoperoxidation with H2O2 that can persist in water for days with different half-lives. Further studies are needed to understand the role of lipoperoxidation products as acute mediators of disease and death in aquatic environments

Seawater carbonate chemistry and the growth response of the toxic dinoflagellate Karenia selliformis from Patagonian waters of Chile

Northern Patagonia (41–44°S) is affected by climatic, hydrological and oceanographic anomalies, which in synergy with processes such as global warming and acidification of the coastal oceans may affect the frequency and intensity of harmful algal blooms (HABs). Greater frequency of HABs has been reported in the southeastern Pacific Ocean, including blooms of the toxic dinoflagellate Karenia selliformis, causing massive mortality of marine fauna in the oceanic and coastal areas of Patagonia. The objective of this study was to determine the effects of temperature and pH interaction on the growth of K. selliformis (strain CREAN_KS02), since these factors have wide seasonal fluctuations in the Patagonian fjord ecosystem. The CREAN_KS02 strain isolated from the Aysén Region (43°S) was used in a factorial experiment with five pH levels (7.0, 7.4, 7.7, 8.1 and 9.0) and two temperatures (12 and 17 °C) during a period of 18–21 days. Results indicated a significant effect of temperature and pH interaction on growth rate (range 0.22 ± 0.00 to 0.08 ± 0.01 d−1) and maximum density (range 13,710 ± 2,616 to 2,385 ± 809 cells mL−1) of K. selliformis. The highest density and growth of K. selliformis was found at 12 °C with a reduced pH (7.0–7.7). The results suggest that the current environmental conditions of coastal Patagonia, waters of low temperature and relatively low pH, may be favorable for the development of blooms of this species during autumn. We suggest that there is natural plasticity of K. selliformis in a wide pH range (7.0–8.1) but in a narrow low temperature range (10.6–12.9 °C), values that are typically recorded in the oceanic region of northern Patagonia. In contrast, in an extreme climate change scenario (ocean warming and coastal acidification) in northern Patagonia, a negative effect on the growth of K. selliformis may be expected due to amplification of the acidification effects caused by the thermal stress of high temperature water