Technetium-99 ((99)Tc) in annual growth segments of knotted wrack (Ascophyllum nodosum)

Biological Potential, Gastrointestinal Digestion, Absorption, and Bioavailability of Algae-Derived Compounds with Neuroprotective Activity: A Comprehensive Review

Currently, there is no known cure for neurodegenerative disease. However, the available therapies aim to manage some of the symptoms of the disease. Human neurodegenerative diseases are a heterogeneous group of illnesses characterized by progressive loss of neuronal cells and nervous system dysfunction related to several mechanisms such as protein aggregation, neuroinflammation, oxidative stress, and neurotransmission dysfunction. Neuroprotective compounds are essential in the prevention and management of neurodegenerative diseases. This review will focus on the neurodegeneration mechanisms and the compounds (proteins, polyunsaturated fatty acids (PUFAs), polysaccharides, carotenoids, phycobiliproteins, phenolic compounds, among others) present in seaweeds that have shown in vivo and in vitro neuroprotective activity. Additionally, it will cover the recent findings on the neuroprotective effects of bioactive compounds from macroalgae, with a focus on their biological potential and possible mechanism of action, including microbiota modulation. Furthermore, gastrointestinal digestion, absorption, and bioavailability will be discussed. Moreover, the clinical trials using seaweed-based drugs or extracts to treat neurodegenerative disorders will be presented, showing the real potential and limitations that a specific metabolite or extract may have as a new therapeutic agent considering the recent approval of a seaweed-based drug to treat Alzheimer’s disease.

Trophic Transfer of Radioactive Micronutrients in a Shallow Benthic Food Web

The Baltic Sea is one of the most polluted seas in the world, with widespread eutrophication and radionuclide contamination. Using key species of the Baltic Sea, the effects of eutrophication on uptake and trophic transfer of the radioactive micronutrients commonly found in nuclear power plant effluents were investigated experimentally using the brown macroalgae Fucus vesiculosus and the grazers Idotea balthica and Theodoxus fluviatilis in a controlled environment. Rapid uptake of 54 Mn, 57 Co, and 65 Zn from water was observed in all biota; and eutrophication combined with grazing pressure strongly influenced the uptake in F. vesiculosus. Uptake of 54 Mn, 57 Co, and 65 Zn to I. balthica and T. fluviatilis grazing on F. vesiculosus were also observed. The results indicate that ecosystems could be open for further trophic transfer as radionuclides accumulate quickly in the producers and are transferred to primary consumers. Environ Toxicol Chem 2021;40:1694-1705. © 2021 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Distribution of 137Cs in benthic plants along depth profiles in the outer Puck Bay (Baltic Sea)

A study was conducted on three macroalgae species: Polysiphonia fucoides and Furcellaria lumbricalis, the species of the red algae division, and Cladophora glomerata, representing the green algae division, as well as Zostera marina, representing vascular plants. The main aim of the study was to recognize the level of ¹³⁷Cs concentrations in the plants, which could be used as a measurement of bioaccumulation efficiency in the selected macrophytes at varying depths, and in the seasonal resolution of the vegetation period: spring–summer and autumnal. The plants’ biomass clearly showed seasonal variability, as did the ¹³⁷Cs concentrations in the plants. Cesium activity also changed with depth. Seasonal variability in radionuclide content in the plants, as well as the differences in its activity determined along the depth profile, were related mainly to the plant biomass and the dilution effect caused by the biomass increment and reflected the growth dynamics. P. fucoides showed much greater bioaccumulation ability at each depth as compared to C. glomerata, a green algae. Lower concentrations of ¹³⁷Cs were also identified in F. lumbricalis and in Z. marina, mostly as a result of differences in morphology and physiology. P. fucoides can be recommended as a bioindicator for the monitoring of ¹³⁷Cs contamination due to the high efficiency of bioaccumulation and the available biomass along the depth profile, as well as the occurrence throughout the entire vegetation season.

Differential concentration of Technetium-99 (99Tc) in common intertidal molluscs with different food habits

Concentration of 99Tc has been measured in fucoids and molluscs, sampled in a sheltered intertidal at the southwest coast of Norway from February to November 2006. The concentrations of 99Tc in molluscs differed significantly between species. The filtering bivalve Mytilus edulis had the lowest concentrations with averages of 2.3-5.9 Bq kg(-1) d.w., while the herbivorous gastropods Littorinalittorina, Littorina obtusata and Patella vulgata had higher concentrations. P. vulgata and L. obtusata had the highest concentrations, 40-47 and 26-30 Bq kg(-1)d.w., respectively. L. obtusata has a specialized habit of living, and prefers to feed on fucoids. P. vulgata can graze extensively on the fucoid Ascophyllum nodosum when available. Fucoids are known to have very high uptake of 99Tc, and this was also found in the present study. The high 99Tc-concentrations of L. obtusata and P. vulgata are most likely due to their habit of feeding on fucoids.