| 1. |
- Carlsson, Fredrik, et al.
(författare)
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Effect of heat on interspecific competition in saprotrophic wood fungi
- 2014
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Ingår i: Fungal ecology. - : Elsevier BV. - 1754-5048 .- 1878-0083. ; 11, s. 100-106
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Tidskriftsartikel (refereegranskat)abstract
- Some boreal wood fungi that are associated with forest fire or open dry habitats have an increased resistance to heat in comparison to species associated with a less specific distribution or species found in mesic forests. We hypothesize that extreme temperature-stress experienced during fires will favor species adapted to heat and, ultimately, the composition of species inhabiting logs in such habitats will change. Competitiveness after temperature stress was examined in three fire-associated species – Dichomitus squalens, Gloeophyllum sepiarium and Phlebiopsis gigantea – and three non fire-associated species – Ischnoderma benzoinum, Phellinus pini and Fomitopsis pinicola. There was a difference between the fire-associated species and the non fire-associated species with respect to competitive strength after heat stress. All fire-associated species had an advantage after heat treatment, colonizing a larger volume of wood than any non-fire-associated competitor. Our findings suggest that increased heat tolerance of mycelia can exert a competitive balance shift after forest fire. It shows that a system governed by forest fire will be dominance controlled under certain conditions. Furthermore, from a management perspective, during a prescribed burning, certain species already present in the ecosystem will be favored if the fire is not allowed to totally consume the substrates.
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| 2. |
- Carlsson, Fredrik, 1974-, et al.
(författare)
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Increased heat resistance in mycelia from wood fungi prevalent in forests characterized by fire : a possible adaptation to forest fire.
- 2012
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Ingår i: Fungal Biology. - : Elsevier BV. - 1878-6146 .- 1878-6162. ; 116:10, s. 1025-1031
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Tidskriftsartikel (refereegranskat)abstract
- AbstractForest fire has for a long time been the major stand replacing/modifying disturbance in boreal forests. For organisms to adopt to this phenomenon different strategies for protective measurements has evolved. This study focuses on the organism group of wood fungi, and one of several possibilities for adaptation to forest fire - increased heat resistance in the mycelia. 16 species of wood fungi where selected and sorted a priori according to their prevalence for fire affected substrate. These were isolated and re-inoculated on pine wood before testing. Experiments where done in a series where the mycelia was exposed to 100, 140, 180, 220°C for 5, 10, 15, 20, 15 min. A very clear difference was found, the group containing species with a prevalence for a fire affected substrate had a much higher survival rate over all combinations of time and temperature compared to species with a more general ecology. This data suggests that increased heat resistance in mycelia could be a possible adaptation to forest fire. This in turn has major impacts on the ecology and population dynamics of wood fungi. An increase in temperature could shift the population structure in a log, allowing minor non fruiting mycelia content to expand on the expense of earlier dominant colonizers. Furthermore this study has implications on how to control prescribed restoration burning events. When burning areas where the dead wood content is dominated by early decay stages, loss of species can be avoided by proper management.
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| 3. |
- Carlsson, Fredrik, 1974-
(författare)
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Wood Fungi and Forest Fire
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Forest fires have been the major stand-replacing/modifying disturbance in boreal forests. To adapt to fire disturbance, different strategies have evolved. This thesis focuses on wood fungi, and the effect of forest fire on this organism group. In many ways it is a study on adaptation to forest fire, in concurrence with adaptation to dry open habitats. In Paper I we study increased heat resistance in mycelia from species prevalent in fire prone environments. Fungi were cultivated on fresh wood and exposed to different temperatures. Species prevalent in fire affected habitats had a much higher survival rate over all combinations of time and temperature compared to species associated with other environments. Based on this results the competitiveness was tested after temperature stress (paper II), three fire associated species, were tested against three non fire associated species. All fire associated species had a clear advantage after heat treatment, conquering a larger volume of wood than its competitor. In paper III we studied the effect of heat shock on decomposition rate, 18 species was tested. Species were cultivated and monitored for CO2 accumulation for 8 weeks and then heat shocked. All species including non fire associated species seemed to up-regulate decomposition after heat shock, this response was more pronounced in fire associated species. To look at the possible effect of forest fire on population structure (Paper IV), we developed 29 SNP/INDELs for Phlebiopsis. gigantea. We amplified the marker containing fragments in 132 individuals of P. gigantea in 6 populations, 3 which were found in areas affected by forest fire and 3 in unaffected areas. We found no genetic structure in accordance to forest fire. However we detected geographic structure, which stands in contrast to earlier studies. This might be due to the method, using SNP´s and number of individuals in the study. Finally we collected cross-sections of decayed logs to evaluate the number of fungal species domains that are likely to be hit when drilling a saw-dust sample in a log. We used these estimates to simulate how many species that will be found by a certain number of samples. We found that in 99% of the
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| 4. |
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| 5. |
- Larsson, Sara, et al.
(författare)
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Characterization of the Lipid Droplet Proteome of a Clonal Insulin-producing β-Cell Line (INS-1 832/13).
- 2012
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 11:2, s. 1264-1273
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Tidskriftsartikel (refereegranskat)abstract
- Lipids are known to play a crucial role both in the normal control of insulin release and in the deterioration of β-cell function, as observed in type 2 diabetes. Despite this established dual role of lipids, little is known about lipid storage and handling in β-cells. Here, we isolated lipid droplets from oleate-incubated INS-1 832/13 cells and characterized the lipid droplet proteome. In a total of four rounds of droplet isolation and proteomic analysis by HPLC-MS/MS, we identified 96 proteins that were specific to droplets. The proteins fall into six categories based on function or previously observed localization: metabolism, endoplasmic reticulum/ribosomes, mitochondria, vesicle formation and transport, signaling, and miscellaneous. The protein profile reinforces the emerging picture of the lipid droplet as an active and dynamic organelle involved in lipid homeostasis and intracellular trafficking. Proteins belonging to the category mitochondria were highly represented, suggesting that the β-cell mitochondria and lipid droplets form a metabolic unit of potential relevance for insulin secretion.
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| 6. |
- Westman, Anna-Karin
(författare)
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Samtal om begreppskartor : en väg till ökad förståelse
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Denna avhandling belyser hur elevdiskussioner om begreppskartor kan bidra till en ökad förståelse för innebörden av de utvalda biologiska begreppen hos de elever som deltar. Som bakgrund till avhandlingen redovisas forskningsresultat vilka visar ett antal svårigheter elever kan ha inom det cellbiologiska ämnesområdet. Två exempel på detta är de många ämnesspecifika begreppen och att det i cellbiologin finns flera organisationsnivåer. En viktig orsak till dessa svårigheter är naturvetenskapens karaktär, där konkreta fenomen förklaras med abstrakta modeller och teorier. I bakgrunden finns också tidigare forskning som visat att elevers diskussioner med varandra har positiv inverkan på lärandet. Syftet med studierna är att undersöka vilken typ av samtal som uppkommer i en elevgrupp vid konstruktionen av en begreppskarta och vad deltagarna tyckte om uppgiften.Resultat från två delstudier redovisas och diskuteras i avhandlingen. Den första av dessa studier redovisas i Artikel I. Insamlingen av data gjordes då eleverna genomförde en uppgift där de, under diskussioner i små grupper, konstruerade begreppskartor inom ämnet cellandning. Eleverna gick i en avgångsklass på det naturvetenskapliga programmet. Ytterligare data samlades in vid enskilda intervjuer med elever efter genomförandet. Analysen inriktades på i vilken utsträckning uttalanden i diskussionerna var biologiskt korrekta, vilken typ av samtal grupperna genomförde och hur deltagarna upplevde uppgiften. Resultaten visar att många uttalanden är helt eller delvis korrekta. Samtalen innehöll delar där eleverna enbart samtyckte till vad någon annan sagt, men också delar där deltagarna argumenterade för sitt synsätt. Eleverna uttryckte en positiv upplevelse av uppgiften i de efterföljande intervjuerna.Den andra studien redovisas i Artikel II. Studien gjordes i en klass som studerade genetik. Även här diskuterade elevgrupper hur en begreppskarta skulle konstrueras. Data insamlades under diskussioner och vid efterföljande, enskildavintervjuer. Analysen inriktades på tidigare kända svårigheter i genetik, det naturvetenskapliga innehållet i samtalen, samtalens karaktär och hur eleverna upplevde uppgiften. Resultaten visar att elevernas diskussioner utvecklas mot det naturvetenskapliga synsättet genom samtal där de flesta eleverna deltar aktivt och också uttrycker egna synpunkter. I intervjuerna uttrycker eleverna sig positivt om arbetsuppgiften och flera anser att de fått en bättre förståelse av ämnet.Sammanfattningsvis visar resultaten i avhandlingen att samtal om begreppskartor kan bidra till en förbättrad förståelse i cellbiologi.
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