| 1. |
- Khoomrung, Sakda, 1978, et al.
(författare)
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Rapid Quantification of Yeast Lipid using Microwave-Assisted Total Lipid Extraction and HPLC-CAD
- 2013
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Ingår i: Analytical Chemistry. - : American Chemical Society (ACS). - 0003-2700 .- 1520-6882. ; 85:10, s. 4912-4919
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Tidskriftsartikel (refereegranskat)abstract
- We here present simple and rapid methods for fast screening of yeast lipids in Saccharomyces cerevisiae. First we introduced a microwave-assisted technique for fast lipid extraction that allows the extraction of lipids within 10 min. The new method enhances extraction rate by 27 times, while maintaining product yields comparable to conventional methods (n = 14, P > 0.05). The recovery (n = 3) from spiking of synthetic standards were 92 +/- 6% for cholesterol, 95 +/- 4% for triacylglycerol, and 92 +/- 4% for free fatty acids. Additionally, the new extraction method combines cell disruption and extraction in one step, and the approach, therefore, not only greatly simplifies sample handling but also reduces analysis time and minimizes sample loss during sample preparation. Second, we developed a chromatographic separation that allowed separation of neutral and polar lipids from the extracted samples within a single run. The separation was performed based on a three gradient solvent system combined with hydrophilic interaction liquid chromatography-HPLC followed by detection using a charged aerosol detector. The method was shown to be highly reproducible in terms of retention time of the analytes (intraday; 0.002-0.034% RSD; n = 10, interday; 0.04-1.35% RSD; n = 5) and peak area (intraday; 0.63-6% RSD; n = 10, interday; 4-12% RSD; n = 5).
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| 2. |
- Lekberg, Ylva, et al.
(författare)
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Fatty acid 16:1ω5 as a proxy for arbuscular mycorrhizal fungal biomass : current challenges and ways forward
- 2022
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Ingår i: Biology and Fertility of Soils. - : Springer Science and Business Media LLC. - 0178-2762 .- 1432-0789. ; 58:8, s. 835-842
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Tidskriftsartikel (refereegranskat)abstract
- Fatty acid biomarkers have emerged as a useful tool to quantify biomass of various microbial groups. Here we focus on the frequent use of the fatty acid 16:1ω5 as a biomarker for arbuscular mycorrhizal (AM) fungi in soils. We highlight some issues with current applications of this method and use several examples from the literature to show that the phospholipid fatty acid (PLFA) 16:1ω5 can occur in high concentrations in soils where actively growing AM fungi are absent. Unless the study includes a control where the contribution of other microbes can be estimated, we advocate for the use of the neutral lipid fatty acid (NLFA) 16:1ω5. This biomarker has higher specificity, is more responsive to shifts in AM fungal biomass, and quantification can be conducted along with PLFA analysis without doubling analytical efforts. We conclude by contrasting various methods used to measure AM fungal biomass in soil and highlight future research needs to optimize fatty acid analyses.
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| 3. |
- Teixeira, Pedro P.C., et al.
(författare)
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Decoding the rhizodeposit-derived carbon's journey into soil organic matter
- 2024
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Ingår i: Geoderma. - 0016-7061. ; 443
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Tidskriftsartikel (refereegranskat)abstract
- Net rhizodeposition corresponds to the portion of living root carbon (C) that remains in the soil after microbial processing and partial decomposition. Although it is assumed that this C input exerts an important role in the formation of soil organic matter (SOM), its contribution to distinct SOM pools is still not fully understood. In this study, we aimed to (i) quantify the retention of net rhizodeposition C in the different SOM fractions and in reactive Al and Fe mineral phases and (ii) investigate how rhizodeposition drives the spatial distribution of microbial communities in the rhizosphere. To track the transfer of net rhizodeposition into the soil, we used artificially labeled eucalypt (Eucalyptus spp.) seedlings under a 13C-CO2 atmosphere (multiple-pulse labeling). Combining physical SOM fractionation and the chemical extraction of aluminum (Al) and iron (Fe) reactive phases, we studied the distribution of net rhizodeposition into different soil fractions. We also assessed the 13C incorporation into microbial phospholipid fatty acids (PLFAs) at different distances from the roots. Our results show that 76 % of the net rhizodeposition 13C was retained within the mineral-associated organic matter (MAOM) fraction. About 28 % of net rhizodeposition 13C within the MAOM fraction was retained within the Al and Fe reactive phases, indicating that this is a sizeable mechanism for the retention of net rhizodeposition in soil. Rhizodeposition increased the abundance of microbial PLFAs exclusively in the soil close to the roots (0–4 mm), with prominent incorporation of net rhizodeposition 13C into fungal biomarkers. Overall, our findings underscore the importance of mineral associations for the retention of net rhizodeposition in the soil. We also highlight the role of fungi in transferring the root-derived C beyond the root vicinity and promoting the formation of occluded SOM.
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| 4. |
- Verbruggen, Erik, et al.
(författare)
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Do arbuscular mycorrhizal fungi stabilize litter-derived carbon in soil?
- 2016
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Ingår i: Journal of Ecology. - : Wiley. - 1365-2745 .- 0022-0477. ; 104:1, s. 261-269
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Tidskriftsartikel (refereegranskat)abstract
- 1. Fine roots and mycorrhiza often represent the largest input of carbon (C) into soils and are therefore of primary relevance to the soil C balance. Arbuscular mycorrhizal (AM) fungi have previously been found to increase litter decomposition which may lead to reduced soil C stocks, but these studies have focused on immediate decomposition of relatively high amounts of high-quality litter and may therefore not hold in many ecological settings over longer terms. 2. Here, we assessed the effect of mycorrhizal fungi on the fate of C and nitrogen (N) contained within a realistic amount of highly C-13-/N-15-labelled root litter in soil. This litter was either added fresh or after a 3-month incubation period under field conditions to a hyphal in-growth core where mycorrhizal abundance was either reduced or not through rotation. After 3 months of incubation with a plant under glasshouse conditions, the effect of turning cores on residual C-13 and N-15 inside the cores was measured, as well as C-13 incorporation in microbial signature fatty acids and N-15 incorporation of plants. 3. Turning of cores increased the abundance of fungal decomposers and C-13 loss from cores, while N-15 content of cores and plants was unaffected. Despite the difference in disturbance that turning the cores could have caused, the results suggest that mycorrhizal fungi and field incubation of litter acted to additively increase the proportion of C-13 left in cores. 4. Synthesis. Apart from stimulating litter decomposition as previously shown, mycorrhizas can also stabilize C during litter decomposition and this effect is persistent through time.
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