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- Broman, Elias, 1985-, et al.
(författare)
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Biotic interactions between benthic infauna and aerobic methanotrophs mediate methane fluxes from coastal sediments
- 2024
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Ingår i: The ISME journal. - 1751-7370 .- 1751-7362. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Coastal ecosystems dominate oceanic methane (CH4) emissions. However, there is limited knowledge about how biotic interactions between infauna and aerobic methanotrophs (i.e. CH4 oxidizing bacteria) drive the spatial-temporal dynamics of these emissions. Here, we investigated the role of meio- and macrofauna in mediating CH4 sediment-water fluxes and aerobic methanotrophic activity that can oxidize significant portions of CH4. We show that macrofauna increases CH4 fluxes by enhancing vertical solute transport through bioturbation, but this effect is somewhat offset by high meiofauna abundance. The increase in CH4 flux reduces CH4 pore-water availability, resulting in lower abundance and activity of aerobic methanotrophs, an effect that counterbalances the potential stimulation of these bacteria by higher oxygen flux to the sediment via bioturbation. These findings indicate that a larger than previously thought portion of CH4 emissions from coastal ecosystems is due to faunal activity and multiple complex interactions with methanotrophs.
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- Broman, Elias, 1985-, et al.
(författare)
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No evidence of light inhibition on aerobic methanotrophs in coastal sediments using eDNA and eRNA
- 2023
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Ingår i: Environmental DNA. - 2637-4943. ; 5:4, s. 766-781
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Tidskriftsartikel (refereegranskat)abstract
- It is estimated that up to half of global methane (CH4) emissions are derived from microbial processes in aquatic ecosystems. However, it is not fully understood which factors explain the spatial and temporal variability of these emissions. For example, light has previously been shown to both inhibit and stimulate aerobic methane-oxidizing bacteria (i.e., methanotrophs) in the water column. These contrasting results indicate that the mechanisms that light has on CH4 oxidation are not yet clearly known, even less so for benthic aerobic methanotrophs. Here, we tested whether light reaching the seafloor can inhibit methanotrophic activity on the sediment surface. We sampled and distributed over 40 intact sediment cores from two coastal sites (illuminated 10 m, and a dark site at 33 m water depth) into 0, 50, and 100 PAR light treatments. After 10 days, we found no difference between treatments for each site in pore-water CH4 concentrations, relative abundance of aerobic methanotrophs, or the number of RNA transcripts related to methane oxidation. Our results suggest that light attenuation in coastal waters does not significantly affect aerobic methanotrophs in coastal sediments.
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- Capo, Eric, et al.
(författare)
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Oxygen-deficient water zones in the Baltic Sea promote uncharacterized Hg methylating microorganisms in underlying sediments
- 2022
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Ingår i: Limnology and Oceanography. - : Wiley. - 1939-5590 .- 0024-3590. ; 67:1, s. 135-146
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Tidskriftsartikel (refereegranskat)abstract
- Human-induced expansion of oxygen-deficient zones can have dramatic impacts on marine systems and its resident biota. One example is the formation of the potent neurotoxic methylmercury (MeHg) that is mediated by microbial methylation of inorganic divalent Hg (HgII) under oxygen-deficient conditions. A negative consequence of the expansion of oxygen-deficient zones could be an increase in MeHg production due to shifts in microbial communities in favor of microorganisms methylating Hg. There is, however, limited knowledge about Hg-methylating microbes, i.e., those carrying hgc genes critical for mediating the process, from marine sediments. Here, we aim to study the presence of hgc genes and transcripts in metagenomes and metatranscriptomes from four surface sediments with contrasting concentrations of oxygen and sulfide in the Baltic Sea. We show that potential Hg methylators differed among sediments depending on redox conditions. Sediments with an oxygenated surface featured hgc-like genes and transcripts predominantly associated with uncultured Desulfobacterota (OalgD group) and Desulfobacterales (including Desulfobacula sp.) while sediments with a hypoxic-anoxic surface included hgc-carrying Verrucomicrobia, unclassified Desulfobacterales, Desulfatiglandales, and uncharacterized microbes. Our data suggest that the expansion of oxygen-deficient zones in marine systems may lead to a compositional change of Hg-methylating microbial groups in the sediments, where Hg methylators whose metabolism and biology have not yet been characterized will be promoted and expand.
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- Nordin, Steven, 1960-, et al.
(författare)
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A longitudinal descriptive study of self-reported abnormal smell and taste perception in pregnant women
- 2004
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Ingår i: Chemical Senses. - : Oxford University Press. - 0379-864X .- 1464-3553. ; 29:5, s. 391-402
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Tidskriftsartikel (refereegranskat)abstract
- Self-reported abnormal sensitivity, qualitative distortions and phantom sensations with respect to smell and taste was assessed with a longitudinal design, based on questions referring to gestational weeks 13–16 and 31–34 of pregnancy in comparison with 9–12 weeks post partum and with non-pregnant women with corresponding time durations and intervals. The results show that abnormal smell and/or taste perception was reported by 76% of the pregnant women, typically believed to be caused by their pregnancy. Increased smell sensitivity was found to be very common at the early stage of pregnancy (67% of all pregnant respondents) and occasionally accompanied by qualitative smell distortions (17%) and phantom smells (14%). The smell abnormalities were less common at the late pregnancy stage and almost absent post partum. Abnormal taste sensitivity was fairly commonly reported (26%), often described as increased bitter sensitivity and decreased salt sensitivity. These results, suggesting that abnormal smell and/or taste perception is experienced by a large majority of pregnant women, imply that further research is needed to understand to what extent these chemosensory changes may underlie food aversions and craving with implications for food intake during pregnancy.
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- Nordin, Steven, 1960-, et al.
(författare)
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Gender differences in factors affecting rejecting of food in healthy young Swedish adults
- 2004
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Ingår i: Appetite. - : Elsevier BV. - 0195-6663 .- 1095-8304. ; 43:3, s. 295-301
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Tidskriftsartikel (refereegranskat)abstract
- With the objectives to better understand gender-related differences in variables of importance for food intake, and interrelations between these variables, 100 healthy, young women and 100 healthy, young men responded to self-administrated questionnaires about general food rejection, learned illness-associated food aversions, disgust (the Disgust Scale), food neophobia (the Food Neophobia Scale), nausea and appetite. The results show that food rejection and aversions were more common in women (69 and 38%, respectively) than in men (47 and 18%), and that women are more disgust sensitive than men. However, no differences between women and men were observed regarding reasons for rejecting food (predominantly sensory attributes), prevalence of gastrointestinal illness as an associated aversion symptom (95 vs 89%), type of aversive food due to associated illness (predominantly high protein items), or food neophobia. Based on path analyses, a model is proposed of interrelations between disgust, food neophobia, learned food aversions, nausea, appetite, and general food rejection in healthy young adults.
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- Skolin, Inger, et al.
(författare)
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Altered food intake and taste perception in children with cancer after start of chemotherapy : perspectives of children, parents and nurses.
- 2006
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Ingår i: Supportive Care in Cancer. - : Springer Science and Business Media LLC. - 0941-4355 .- 1433-7339. ; 14:4, s. 369-378
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Tidskriftsartikel (refereegranskat)abstract
- GOALS OF WORK: The purpose of this study was to better understand various variables related to food intake and eating problems in children with cancer during their chemotherapy. PATIENTS AND METHODS: Twenty-two consecutively admitted children, diagnosed with cancer and undergoing chemotherapy, participated in this study. Twenty-one of them, their parents and attending nurses participated in semi-structured interviews. Ten of the children underwent a taste acuity test, and recognition thresholds for the four basic tastes were determined. MAIN RESULTS: The shared view of both children and parents was that altered taste was the predominant cause of the eating problems. In contrast, the nurses perceived that nausea was the most important cause of the children's eating problems. In addition, psychological aspects such as learned food aversions and negative attitudes towards hospital food were regarded as important by children, parents and nurses. The taste test showed that the patients had higher thresholds for bitter taste and made more taste recognition errors compared to controls. CONCLUSIONS: Changes seem to exist both in the primary gustatory sense as well as in food perception in paediatric cancer patients undergoing chemotherapy. Single solutions, such as efforts to serve "tasty food", do not suffice alone. A more effective solution may be to combine different strategies and combinations of oral, enteral and parenteral nutrition should be considered to prevent malnutrition.
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