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Algae contain a number of anti-inflammatory bioactive compounds such as omega-3 polyunsaturated fatty acids (n-3 PUFA) and chlorophyll a, hence as dietary ingredients, their extracts may be effective in chronic inflammation-linked metabolic diseases such as cardiovascular disease. In this study, anti-inflammatory potential of lipid extracts from three red seaweeds (Porphyra dioica, Palmaria palmata and Chondrus crispus) and one microalga (Pavlova lutheri) were assessed in lipopolysaccharide (LPS)-stimulated human THP-1 macrophages. Extracts contained 34%–42% total fatty acids as n-3 PUFA and 5%–7% crude extract as pigments, including chlorophyll a, β-carotene and fucoxanthin. Pretreatment of the THP-1 cells with lipid extract from P. palmata inhibited production of the pro-inflammatory cytokines interleukin (IL)-6 (p < 0.05) and IL-8 (p < 0.05) while that of P. lutheri inhibited IL-6 (p < 0.01) production. Quantitative gene expression analysis of a panel of 92 genes linked to inflammatory signaling pathway revealed down-regulation of the expression of 14 pro-inflammatory genes (TLR1, TLR2, TLR4, TLR8, TRAF5, TRAF6, TNFSF18, IL6R, IL23, CCR1, CCR4, CCL17, STAT3, MAP3K1) by the lipid extracts. The lipid extracts effectively inhibited the LPS-induced pro-inflammatory signaling pathways mediated via toll-like receptors, chemokines and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling molecules. These results suggest that lipid extracts from P. lutheri, P. palmata, P. dioica and C. crispus can inhibit LPS-induced inflammatory pathways in human macrophages. Therefore, algal lipid extracts should be further explored as anti-inflammatory ingredients for chronic inflammation-linked metabolic diseases.

Local and global changes associated with anthropogenic activities are impacting marine and terrestrial ecosystems. Macroalgae, especially habitat-forming species like kelp, play critical roles in temperate coastal ecosystems. However, their abundance and distribution patterns have been negatively affected by warming in many regions around the globe. Along with global change, coastal ecosystems are also impacted by local drivers such as eutrophication. The interaction between global and local drivers might modulate kelp responses to environmental change. This study examines the regulatory effect of no 3 − on the thermal plasticity of the giant kelp Macrocystis pyrifera. To do this, thermal performance curves (TPCs) of key temperature-dependant traits-growth, photosynthesis, NO 3 − assimilation and chlorophyll a fluorescence-were examined under nitrate replete and deplete conditions in a short-term incubation. We found that thermal plasticity was modulated by NO 3 − but different thermal responses were observed among traits. Our study reveals that nitrogen, a local driver, modulates kelp responses to high seawater temperatures, ameliorating the negative impacts on physiological performance (i.e. growth and photosynthesis). However, this effect might be species-specific and vary among biogeographic regions -thus, further work is needed to determine the generality of our findings to other key temperate macroalgae that are experiencing temperatures close to their thermal tolerance due to climate change.Rising levels of atmospheric CO 2 are causing increases in air and sea surface temperatures (SSTs), with the mean SST predicted to rise by 1.4 °C to 4.8 °C by 2100 1 . With global warming, extreme high temperature events such as marine heat waves (MHWs) have also increased in frequency, intensity and duration along the World's coastline, including the Mediterranean, Australia and Brazilian Atlantic sea 2-6 . These anomalous elevated temperatures have negatively impacted marine and terrestrial ecosystems by altering species' composition and distribution patterns 7-9 . Such ecological changes are also severely impacting ecosystem goods and services such as fisheries, and carbon sequestration and storage 10 . The impacts of warming are considerably larger in marine systems because of their greater sensitivity to these global stressors compared to terrestrial systems 11,12 . Because of this, there is rising concern about the capacity of marine species to acclimate quickly enough to short-term variability in temperature, which will be critical for organisms to adapt and survive in a changing ocean 13,14 .In ectothermic organisms such as plants, algae, invertebrates and lower vertebrates, temperature is the major factor regulating their physiology, growth, performance and fitness [15][16][17][18][19][20] . Therefore, changes in environmental temperatures (T a ) due to climate change will trigger modifications at physiological and biochemical levels, influencing whole-organism thermal plasticity (i.e. thermal sensitivities and...

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Intra-thallus variation in fatty acid and pigment contents and profiles was investigated in five species of Laminariales (Alaria esculenta, Laminaria digitata, Laminaria hyperborea, Saccharina latissima, and Saccorhiza polyschides), and three Fucales (Ascophyllum nodosum, Fucus serratus, and Himanthalia elongata). Significant variation occurred across all species and compounds examined. Total fatty acids were generally higher in the fronds, with highest levels and largest variability observed in A. nodosum (1.5% of dry weight (DW) in the base, 6.3% of DW in frond tips). Percentages of the omega-3 fatty acids 18:4 n-3 and 20:5 n-3 were generally higher in more distal parts, while 20:4 n-6 exhibited a contrasting pattern, with higher levels in basal structures and holdfasts. Trends for pigments were similar to those for fatty acids in Laminariales. In the Fucales, highest levels were detected in the mid-fronds, with lower concentrations in meristematic areas. Highest levels and greatest variability in pigments (e.g., chl a) was observed in F. serratus (1.07 mg · g(-1) DW in the base, 3.04 mg · g(-1) DW in the mid frond). Intra-thallus variability was attributed to physiological functions of the respective thallus sections, e.g., photosynthetic activity, meristematic tissue, and to variations in physical attributes of the structures investigated. Regarding potential commercial nutritional applications, fronds appeared to represent most suitable source materials, due to higher levels of pigments, polyunsaturated fatty acids, and more preferable omega-3/omega-6 ratios.