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Transcriptomes were analyzed for two related hyperthermophilic archaeal species, the piezophilic Thermococcus barophilus strain MP and piezosensitive Thermococcus kodakarensis strain KOD1 subjected to high hydrostatic pressures. A total of 378 genes were differentially expressed in T. barophilus cells grown at 0.1, 40 and 70 MPa, whereas 141 genes were differentially regulated in T. kodakarensis cells grown at 0.1 and 25 MPa. In T. barophilus cells grown under stress conditions (0.1 and 70 MPa), 178 upregulated genes were distributed among three clusters of orthologous groups (COG): energy production and conversion (C), inorganic ion transport and metabolism (P) and carbohydrate transport and metabolism (G), whereas 156 downregulated genes were distributed among: amino acid transport and metabolism (E), replication, recombination and repair (L) and nucleotide transport and metabolism (F). The expression of 141 genes was regulated in T. kodakarensis cells grown under stress conditions (25 MPa); 71 downregulated genes belong to three COG: energy production and conversion (C), amino acid transport and metabolism (E) and transcription (K), whereas 70 upregulated genes are associated with replication, recombination and repair (L), coenzyme transport (H) and defense mechanisms (V).
Seaweeds have recently been shown to contain a significant proportion of arsenic in the form of arsenolipids (AsLp). Three strains of the filamentous brown alga Ectocarpus species were grown in the laboratory with different simulations of environmental stress: control conditions (1/2 Provasoli-enriched seawater), low nitrate (30 % of the amount of nitrates in the control), low phosphate (30 % of the amount of phosphate in the control) and under oxidative stress levels (2 mM H2O2). Generally, the major AsLp was an arsenic-containing hydrocarbon, AsHC360 (50–80 %), but additionally, several arsenic-containing phospholipids (AsPL) were identified and quantified using high-performance liquid chromatography–inductively coupled plasma mass spectrometry and electrospray ionisation mass spectrometry (HPLC-ICP-MS/ESI-MS). The AsLps in cultures were compared with AsLps in Ectocarpus found in its natural habitat as well as with other brown filamentous algae. The AsLp and arsenosugar profiles differed depending on the experimental conditions. Under low phosphate conditions, a significant reduction of phosphorus-containing arsenosugars was noticed, and a significant increase of phosphate-containing AsLps was found when compared with the controls. Strains grown under oxidative stress showed a significant increase in AsLps as well as clear physiological changes.
Regulators have been reluctant to set maximum levels (ML) for arsenic in food because of the molecular diversity of the arsenic species present. Arsenic levels in food can vary by several orders of magnitude, with the arsenic present in many different molecular forms which vary substantially in toxicity. Arsenic in food is found as a multitude of different organoarsenic species and as inorganic arsenic (iAs). iAs is regarded as the most toxic form of arsenic in food and feed and is classified as a carcinogen by the International Agency for Research on Cancer (IARC). Organoarsenic species are, in general, believed to be of low toxicity or even non-toxic, eg, most of the arsenic in fish occurs as non-toxic arsenobetaine.
Lipid and microbial quality of smoked capelin (two groups differing in lipid content) and sardine was studied, with the aim of introducing capelin in the smoked sardine markets. Lipid hydrolysis (phospholipid and free fatty acids) and oxidation index (hydroperoxides and thiobarbituric acid-reactive substances), fatty acid composition, and total viable count were measured in raw and packaged smoked fish during chilled storage (day 2, 10, 16, 22 , 28). Lipid hydrolysis was more pronounced in low lipid capelin, whereas accelerated lipid oxidation occurred in high lipid capelin. Muscle lipid was less stable in sardine than capelin. Essential polyunsaturated fatty acids (eicosapentaenoic acid and docosahexaenoic acid) constituted 12% of fatty acids in capelin and 19% in sardine. Vacuum packaging as well as hot smoking retarded bacterial growth, recording counts of ≤log 5 CFU / g compared to ≥log 7CFU / g in cold smoked air packaged. Smoked low lipid capelin was considered an alternative for introduction into smoked sardine markets.
Colonization of life on Surtsey has been observed systematically since the formation of the island 50 years ago. Although the first colonizers were prokaryotes, such as bacteria and blue – green algae, most studies have been focused on the settlement of plants and animals but less on microbial succession. To explore microbial colonization in diverse soils and the influence of associated vegetation and birds on numbers of environmental bacteria, we collected 45 samples from different soil types on the surface of the island. Total viable bacterial counts were performed with the plate count method at 22, 30 and 37 ° C for all soil samples, and the amount of organic matter and nitrogen (N) was measured. Selected samples were also tested for coliforms, faecal coliforms and aerobic and anaerobic bacteria. The subsurface biosphere was investigated by collecting liquid subsurface samples from a 181 m borehole with a special sampler. Diversity analysis of uncultivated biota in samples was performed by 16S rRNA gene sequences analysis and cultivation. Correlation was observed between nutrient deficits and the number of microorganisms in surface soil samples. The lowest number of bacteria (1 × 104–1 × 105 cells g−1) was detected in almost pure pumice but the count was significantly higher (1 × 106–1 × 109 cells g−1) in vegetated soil or pumice with bird droppings. The number of faecal bacteria also correlated to the total number of bacteria and type of soil. Bacteria belonging to Enterobacteriaceae were only detected in vegetated samples and samples containing bird droppings. The human pathogens Salmonella, Campylobacter and Listeria were not in any sample. Both thermophilic bacteria and archaea 16S rDNA sequences were found in the subsurface samples collected at 145 and 172 m depth at 80 and 54 ° C, respectively, but no growth was observed in enrichments. The microbiota sequences generally showed low affiliation to any known 16S rRNA gene sequences.
Upon oxidation of the polyunsaturated fatty acids in fish oil, either before ingestion or, as recently shown, during the gastrointestinal passage, a cascade of potentially cytotoxic peroxidation products, such as malondialdehyde and 4-hydroxy-2-hexenal, can form. In this study, we digested fresh and oxidized cod liver oils in vitro, monitored the levels of lipid peroxidation products and evaluated oxidative, proteomic and inflammatory responses to the two types of digests in the yeast Saccharomyces cerevisiae and human monocyte-derived dendritic cells.
Digests of cod liver oil with 22-53 Lmol L (-1) malondialdehyde and 0.26-3.7 µmol L (-1) 4-hydroxy-2-hexenal increased intracellular oxidation and cell energy metabolic activity compared to a digested blank in yeast cells and the influence of digests on mitochondrial protein expression was more pronounced for oxidized cod liver oil than fresh cod liver oil. The four differentially expressed and identified proteins were related to energy metabolism and oxidative stress response. Maturation of dendritic cells was affected in the presence of digested fresh cod liver oil compared to the digested blank, measured as lower CD86 expression. The ratio of secreted cytokines, IL-12p40 / IL-10, suggested a pro-inflammatory effect of the digested oils in relation to the blank (1.47-1.67 vs. 1.07).
Gastrointestinal digestion of cod liver oil increases the amount of oxidation products and resulting digests affect oxidation in yeast and immunomodulation of dendritic cells.
Ocean Sampling Day was initiated by the EU-funded Micro B3 (Marine Microbial Biodiversity, Bioinformatics, Biotechnology) project to obtain a snapshot of the marine microbial biodiversity and function of the world's oceans. It is a simultaneous global mega-sequencing campaign aiming to generate the largest standardized microbial data set in a single day. This will be achievable only through the coordinated efforts of an Ocean Sampling Day Consortium, supportive partnerships and networks between sites. This commentary outlines the establishment, function and aims of the Consortium and describes our vision for a sustainable study of marine microbial communities and their embedded functional traits.
Despite the potential benefits of long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs), intake is often low because of low consumption of oily seafood. Microencapsulated fish oil powder can improve tolerance and acceptance of LC n-3 PUFAs. Bioavailability is important to achieve efficacy. We investigated the bioavailability of LC n-3 PUFAs from microencapsulated powder in comparison with meals enriched with liquid fish oil.
Participants (N = 99, age⩾50 years) of this 4-week double-blinded dietary intervention were randomized into three groups. Group 1 (n = 38) received 1.5 g / d eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) as ready-to-eat meals enriched with liquid fish oil; group 2 (n = 30) received the same amount of these LC n-3 PUFAs as microencapsulated fish oil powder and regular meals; and group 3 (n = 31) was the control group, which received placebo powder and regular meals. Blood samples were taken from fingertips at baseline and at the end point.
Seventy-seven subjects (77.8%) completed the study. The amount of EPA in blood doubled in both groups that received LC n-3 PUFAs (P <0.05), but it did not change in the control group. The changes in DHA were less but still significant in both intervention groups. According to multivariate analysis, both intervention groups had higher end-point LC n-3 PUFA concentrations compared with placebo, but differences between intervention groups were not significant.
Bioavailability of LC n-3 PUFAs in encapsulated powder is very similar to the bioavailability of LC n-3 PUFAs in ready-to-eat meals enriched with liquid fish oil. Thus, encapsulated powder can be considered useful to increase LC n-3 PUFA concentrations in blood.
Bioactive compounds from Fucus vesiculosus were extracted and their antioxidant efficacy in fish-oil-enriched foods was evaluated. Water extract (WE) and ethyl acetate fraction (EAF) were obtained and characterized. Furthermore, WE and EAF were added to fish-oil-enriched milk or mayonnaise. Oxidation during storage was evaluated. EAF showed highest phenolic and pigment contents compared with WE. Antioxidant efficacy was found to be dependent on the concentration in the foods. Furthermore, high antioxidant activity in the foods was related to high radical scavenging, high or moderate metal chelating ability, as well as high phenolic and carotenoid contents.