| 1. |
- Bidartondo, Martin, et al.
(författare)
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Preserving accuracy in GenBank
- 2008
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Ingår i: Science. ; 319:5870
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Lindström, Stafva, et al.
(författare)
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Trends in bacterial and fungal communities in ant nests observed with Terminal-Restriction Fragment Length Polymorphism (T-RFLP) and Next Generation Sequencing (NGS) techniques-validity and compatibility in ecological studies
- 2018
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Ingår i: PeerJ. - : PeerJ Inc.. - 2167-8359. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- Microbes are ubiquitous and often occur in functionally and taxonomically complex communities. Unveiling these community dynamics is one of the main challenges of microbial research. Combining a robust, cost effective and widely used method such as Terminal Restriction Fragment Length Polymorphism (T-RFLP) with a Next Generation Sequencing (NGS) method (Illumina MiSeq), offers a solid alternative for comprehensive assessment of microbial communities. Here, these two methods were combined in a study of complex bacterial and fungal communities in the nest mounds of the ant Formica exsecta, with the aim to assess the degree to which these methods can be used to complement each other. The results show that these methodologies capture similar spatiotemporal variations, as well as corresponding functional and taxonomical detail, of the microbial communities in a challenging medium consisting of soil, decomposing plant litter and an insect inhabitant. Both methods are suitable for the analysis of complex environmental microbial communities, but when combined, they complement each other well and can provide even more robust results. T-RFLP can be trusted to show similar general community patterns as Illumina MiSeq and remains a good option if resources for NGS methods are lacking.
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| 3. |
- Rasmussen, Pil U., et al.
(författare)
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Plant and insect genetic variation mediate the impact of arbuscular mycorrhizal fungi on a natural plant-herbivore interaction
- 2017
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Ingår i: Ecological Entomology. - : Wiley. - 0307-6946 .- 1365-2311. ; 42:6, s. 793-802
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Tidskriftsartikel (refereegranskat)abstract
- 1. While both arbuscular mycorrhizal (AM) fungi and plant and insect genotype are well known to influence plant and herbivore growth and performance, information is lacking on how these factors jointly influence the relationship between plants and their natural herbivores. 2. The aim of the present study was to investigate how a natural community of arbuscular mycorrhizal fungi affects the growth of the perennial herb Plantago lanceolata L. (Plantaginaceae), as well as its interaction with the Glanville fritillary butterfly [Melitaea cinxia L. (Nymphalidae)]. For this, a multifactorial experiment was conducted using plant lines originating from multiple plant populations in the angstrom land Islands, Finland, grown either with or without mycorrhizal fungi. For a subset of plant lines, the impact of mycorrhizal inoculation, plant line, and larval family on the performance of M. cinxia larvae were tested. 3. Arbuscular mycorrhizal inoculation did not have a consistently positive or negative impact on plant growth or herbivore performance. Instead, plant genetic variation mediated the impact of arbuscular mycorrhizal fungi on plant growth, and both plant genetic variation and herbivore genetic variation mediated the response of the herbivore. For both the plant and insect, the impact of the arbuscular mycorrhizal community ranged from mutualistic to antagonistic. Overall, the present findings illustrate that genetic variation in response to mycorrhizal fungi may play a key role in the ecology and evolution of plant-insect interactions.
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| 4. |
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| 5. |
- Rodríguez, Juanjo, et al.
(författare)
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Bacterial communities as indicators of environmental pollution by POPs in marine sediments
- 2021
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Ingår i: Environmental Pollution. - : Elsevier. - 0269-7491 .- 1873-6424. ; 268
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Tidskriftsartikel (refereegranskat)abstract
- Decades of intensive discharge from industrial activities into coastal systems has resulted in the accumulation of a variety of persistent organic pollutants (POPs) in marine waters and sediments, having detrimental impacts on aquatic ecosystems and the resident biota. POPs are among the most hazardous chemicals originating from industrial activities due to their biotoxicity and resistance to environmental degradation. Bacterial communities are known to break down many of these aromatic compounds, and different members of naturally occurring bacterial consortia have been described to work in syntrophic association to thrive in heavily contaminated waters and sediments, making them potential candidates as bioindicators of environmental pollution. In this study environmental, sampling was combined with chemical analysis of pollutants and high-resolution sequencing of bacterial communities using Next Generation Sequencing molecular biology tools. The aim of the present study was to describe the bacterial communities from marine sediments containing high loads of POPs and to identify relevant members of the resident microbial communities that may act as bioindicators of contamination. Marine sediments were collected from a coastal bay area of the Baltic Sea historically influenced by intense industrial activity, including metal smelting, oil processing, and pulp and paper production. Different types of POPs were detected at high concentrations. Fiberbank sediments, resulting from historic paper industry activity, were found to harbour a clearly distinct bacterial community including a number of bacterial taxa capable of cellulolytic and dechlorination activities. Our findings indicate that specific members of the bacterial communities thrive under increasing levels of POPs in marine sediments, and that the abundances of certain taxa correlate with specific POPs (or groups), which could potentially be employed in monitoring, status assessment and environmental management purposes.
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| 6. |
- Rodríguez, Juanjo, et al.
(författare)
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Effects of Organic Pollutants on Bacterial Communities Under Future Climate Change Scenarios
- 2018
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Coastal ecosystems are highly dynamic and can be strongly influenced by climate change, anthropogenic activities (e.g. pollution) and a combination of the two pressures. As a result of climate change, the northern hemisphere is predicted to undergo an increased precipitation regime, leading in turn to higher terrestrial runoff and increased river inflow. This increased runoff will transfer terrestrial dissolved organic matter (tDOM) and anthropogenic contaminants to coastal waters. Such changes can directly influence the resident biology, particularly at the base of the food web, and can influence the partitioning of contaminants and thus their potential impact on the food web. Bacteria have been shown to respond to high tDOM concentration and organic pollutants loads, and could represent the entry of some pollutants into coastal food webs. We carried out a mesocosm experiment to determine the effects of: 1) increased tDOM concentration, 2) organic pollutant exposure, and 3) the combined effect of these two factors, on pelagic bacterial communities. This study showed significant responses in bacterial community composition under the three environmental perturbations tested. The addition of tDOM increased bacterial activity and diversity, while the addition of organic pollutants led to an overall reduction of these parameters, particularly under concurrent elevated tDOM concentration. Furthermore, we identified 33 bacterial taxa contributing to the significant differences observed in community composition, as well as 35 bacterial taxa which responded differently to extended exposure to organic pollutants. These findings point to the potential impact of organic pollutants under future climate change conditions on the basal coastal ecosystem, as well as to the potential utility of natural bacterial communities as efficient indicators of environmental disturbance.
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| 7. |
- Rodriguez Serrano, Juan Jose, et al.
(författare)
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Inputs of Terrestrial Dissolved Organic Matter Enhance Bacterial Production and Methylmercury Formation in Oxic Coastal Water
- 2022
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Ingår i: Frontiers in Microbiology. - : Frontiers Media S.A.. - 1664-302X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Methylmercury (MeHg) is a potent neurotoxin commonly found in aquatic environments and primarily formed by microbial methylation of inorganic divalent mercury (Hg(II)) under anoxic conditions. Recent evidence, however, points to the production of MeHg also in oxic pelagic waters, but the magnitude and the drivers for this process remain unclear. Here, we performed a controlled experiment testing the hypothesis that inputs of terrestrial dissolved organic matter (tDOM) to coastal waters enhance MeHg formation via increased bacterial activity. Natural brackish seawater from a coastal area of the Baltic Sea was exposed to environmentally relevant levels of Hg(II) and additions of tDOM according to climate change scenarios. MeHg formation was observed to be coupled to elevated bacterial production rates, which, in turn, was linked to input levels of tDOM. The increased MeHg formation was, however, not coupled to any specific change in bacterial taxonomic composition nor to an increased abundance of known Hg(II) methylation genes. Instead, we found that the abundance of genes for the overall bacterial carbon metabolism was higher under increased tDOM additions. The findings of this study may have important ecological implications in a changing global climate by pointing to the risk of increased exposure of MeHg to pelagic biota.
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| 8. |
- Timonen, Sari, et al.
(författare)
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Dynamics of cytoskeletal proteins in developing pine ectomycorrhiza
- 1996
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Ingår i: Mycorrhiza. - : Springer Science and Business Media LLC. - 1432-1890 .- 0940-6360. ; 6:5, s. 423-429
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Tidskriftsartikel (refereegranskat)abstract
- Mycorrhizal short roots of Pinus contorta Dougl. ex Loud colonized by Suillus variegatus (Sow. ex Fr.) O. Kuntze or Paxillus involutus (Batsch) Fr. were collected 1->60 days after fungal contact. The proteins of the inoculated roots were extracted, electrophoretically separated, blotted and immunostained for alpha-tubulin and actin. The development of the mycorrhiza was also followed microscopically. The signal of plant alpha-tubulin was stronger than the signal of fungal alpha-tubulin during the first 5 days in S. variegatus mycorrhiza and was then exceeded by fungal alpha-tubulin. This correlated well with the increase of fungal mycelium in the mycorrhiza. A transient drop in both plant and fungal alpha-tubulin signals was observed 20 days after fungal contact, suggesting a change in the metabolism of the mycorrhiza. The signals for plant and fungal actins in the mycorrhiza increased steadily during early infection and then remained at a high level as the mycorrhiza matured. Similar trends were observed in P. contorta-P. involutus mycorrhiza. The data from P. contorta-S. variegatus mycorrhizas suggests that alpha-tubulin is a growth-related protein, subject to changes, while the amount of actin reflects the general metabolic activity of the mycorrhiza. In both mycorrhizal systems clear alpha-tubulin and actin signals were detected 60 days after colonization, which indicates that the mycorrhizas were metabolically active in spite of their withered appearance.
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| 9. |
- Timonen, Sari, et al.
(författare)
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Dynamics of phosphorus translocation in intact ectomycorrhizal systems: Non-destructive monitoring using a beta-scanner
- 1996
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Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 1574-6941 .- 0168-6496. ; 19:3, s. 171-180
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Tidskriftsartikel (refereegranskat)abstract
- Phosphorus uptake and translocation through intact mycelial systems of Paxillus involutus and Suillus variegatus infecting Pinus contorta seedlings was monitored non-destructively using a beta-scanner. Mycorrhizal plants were grown in flat perspex chambers (20 x 6 cm(2)) and root growth was restricted to the upper portion of each chamber enabling mycelial translocation to be studied over distances of up to 15 cm. P-32 was supplied, either directly to distal parts of the extending mycelium, or to single, cut mycelial strands in feeding dishes. Two-dimensional patterns of activity were accumulated as scans with a lateral resolution of 5 mm and a longitudinal resolution of 3-4 mm. No distinct translocation front could be detected but patterns of accumulation of label in the mycorrhizal roots were not consistent with movement by simple diffusion. Activity in translocating hyphae became visible only after the activity in mycorrhizal root lips had been visible for a few days. In all cases there was a lag period of 20-50 hours before P-32 could be detected in mycorrhizal root tips. Pre-feeding with unlabelled phosphate had no effect on this lag period. This implies continuous translocation of phosphate at low concentrations and a lag period due to the time needed for detectable levels of phosphate to accumulate in mycorrhizal roots. Thus the minimum velocity of phosphate movement in the hyphae would be 7.5 mm/h, if the first molecules of P-32 arriving at the roots could be detected and the transport distance is 15 cm. Accumulation of phosphate to the roots was fairly constant, but not linear. The phosphorus uptake rate by intact mycelial margins was nearly four orders of magnitude higher than the uptake rate of cut mycorrhizal strands. The results indicate that the fine, foraging hyphae are better suited for nutrient uptake than mycelial strands and that phosphorus translocation in the hyphae occurs by active translocation of small amounts rather than by mass flow.
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| 10. |
- Timonen, Sari, et al.
(författare)
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Identification of cytoskeletal components in pine ectomycorrhizas
- 1993
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Ingår i: New Phytologist. - 1469-8137. ; 124:1, s. 83-92
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Tidskriftsartikel (refereegranskat)abstract
- Ectomycorrhizal associations were synthesized between pine seedlings and the fungi Suillus bovinus (L.) ex Fr. or Paxillus involutus (Batsch ex Fr.) Fr. Immunoblotting of polypeptides separated electrophoretically from crude tissue extracts revealed the abundant presence of tubulin and actin in ectomycorrhiza and lower amounts in the fungal strands surrounding the ectomycorrhizal roots. In ectomycorrhiza the alpha-tubulins from fungal hyphae and plant cells were clearly distinguishable but such discrimination was not possible for beta-tubulin or actin due to the similar mobility of proteins originating from the conifer and fungal tissues. Young ectomycorrhizal short roots were fixed while still attached to the seedlings and, using indirect immunofluorescence microscopy with tubulin antibodies, microtubules were detected in both the conifer cells and in fungal hyphae. In the host plant cytoplasmic and spindle microtubules were visualized in meristem cells and in differentiating vascular tissue but not in the cortical cells. In symbiotic hyphae the microtubule tracks and spindles of dividing nuclei were clearly distinguished in the mantle hyphae in the tip region of the short roots. In the Hartig net hyphae microtubule tracks changed to a less clear, reticulate structure. Actin was visualized as long filaments in vascular tissue cells and as small microfilament bundles in mantle hyphae. Short microtubules and actin dots were detected in cytoplasm-containing hyphae on the strand surface. The possible role of the cytoskeletal elements in the maintenance of the ectomycorrhizal association is discussed.
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