93 research outputs found
Monitoring the control methods of Heterobasidion annosum s.l. root rot
No full textThis thesis summarises the author's work on the effectiveness of two control methods against the necrotrophic fungal pathogen Heterobasidion annosum s.l. (Fr.) Bref. The studied control methods were stump treatments through the application of a fungal biocontrol agent (Phlebiopsis gigantea) and application of urea solution. An additional component to this thesis was to develop a useful Agrobacterium tumefaciens-mediated transformation system for the H. annosum s.l. The potential risk for a build-up in the capacity of H. annosum s.l. to resist overgrowth by P. gigantea was investigated by utilising a P. gigantea strain used in the commercial preparation Rotstop and different strains of H. annosum s.l. The impact on intraspecific genetic diversity from the P. gigantea used in Rotstop four years after stump treatment was estimated using both microsatellite markers and AP-PCR. The long-term effect of urea treatment during first rotation thinning of Picea abies stands was evaluated 15 years post-treatment. An A. tumefaciens-mediated transformation system was developed using two different transformation plasmids and a North American H. annosum strain. The results revealed differences between H. annosum s.l. strains in their ability to resist overgrowth by P. gigantea. This trait was found to be heritable which suggests that H. annosum s.l. has the capacity to develop more tolerant strains against the biocontrol agent if the conditions are met. Also, one QTL effect associated with this trait was identified. Genetic diversity was lower within Rotstop treated plots and the resident population was more genetically similar to the applied P. gigantea strain than other populations sampled in Sweden. This effect on genetic structure was not detected 100-200 m from the treated plot which suggests that stump treatments with P. gigantea only has a local effect on genetic diversity. Urea treated plots exhibited less rot than untreated plots and the urea treatments also significantly reduced the occurrence of windthrown trees. This shows that urea treatment during thinning operations is an efficient method to reduce root rot in P. abies stands. A total of 18 H. annosum s.l. transformants were obtained from the A. tumefaciens-mediated transformation system. The transformants expressed GFP throughout the mycelia and had a normal growth rate. This system will be very useful for genomic work and interaction studies
"Can't seem to live without it somehow" : An interview with Eddy Harris
No full textIn his books about Paris and Harlem and his travelogues about journeys in Africa and the American South, African-American author Eddy L. Harris explores what it means to be Black in the present moment in history. In this interview, he talks to Nicklas Hållén about his need to travel, the craft of travel writing and his plans for a movie project about a journey down the Mississippi River. The conversation revolves particularly around his travelogue Native Stranger: A Blackamerican's Journey into the Heart of Africa (1992) and the way in which identity conditions (and does not condition) travel and travel writing, and the functions that travel writing may have for the author as well as reader. The interview was conducted in the summer of 2013 at a café in the village of Pranzac in the Charente department of France, where Harris currently lives and works.</p
Ångest i organisationen : sambandsstudie om psykosociala arbetsmiljöfaktorer
No full textAbstract Title: Anxiety within the organization - correlation study regarding psychosocial work environment factors. Author: Nicklas Blomqvist The purpose of this study was to examine if there are any correlations between anxiety and psychosocial work environment factors according to Curt Andersson’s theory (2007). The last two decades there has been a significant increase in numbers of employees going on sick leave. According to studies the main explanation for the increase was the psychosocial work environment. One important factor observed in the group of long time sick list was that people working in the public service sector was over represented. By using a survey, the author of this paper has tried to find correlations between different work environmental factors that could contribute to experienced stress in the workplace. The author has also tried to find correlations between experienced stress (e.g. anxiety) and organizational questions. In this study stress represents the measure of the variable anxiety. The survey was conducted in three different pre-school units in a small community in the south of Sweden. More than 70 % of the respondents stated that they had felt stressed recently. A correlation analysis between stress and organizational factors showed a (r.39) correlation that was significant at the 0.01 level (1-tailed). However, the main factor to have an impact on stress (i.e. anxiety) according to the author’s findings was the factor designated job demand. Keywords: Curt Andersson, anxiety, stress, organization, psychosocial workplace environment
Ångest i organisationen : sambandsstudie om psykosociala arbetsmiljöfaktorer
No full textAbstract Title: Anxiety within the organization - correlation study regarding psychosocial work environment factors. Author: Nicklas Blomqvist The purpose of this study was to examine if there are any correlations between anxiety and psychosocial work environment factors according to Curt Andersson’s theory (2007). The last two decades there has been a significant increase in numbers of employees going on sick leave. According to studies the main explanation for the increase was the psychosocial work environment. One important factor observed in the group of long time sick list was that people working in the public service sector was over represented. By using a survey, the author of this paper has tried to find correlations between different work environmental factors that could contribute to experienced stress in the workplace. The author has also tried to find correlations between experienced stress (e.g. anxiety) and organizational questions. In this study stress represents the measure of the variable anxiety. The survey was conducted in three different pre-school units in a small community in the south of Sweden. More than 70 % of the respondents stated that they had felt stressed recently. A correlation analysis between stress and organizational factors showed a (r.39) correlation that was significant at the 0.01 level (1-tailed). However, the main factor to have an impact on stress (i.e. anxiety) according to the author’s findings was the factor designated job demand. Keywords: Curt Andersson, anxiety, stress, organization, psychosocial workplace environment
Supplementary materials for ART and TRT in German
No full textSupplementary materials for:
Hug, Marion, Jarosch, Julian, Eichenauer, Christiane, Pennella, Selina, Kretzschmar, Franziska & Nicklas, Pascal (2024): Some students are more equal: Performance in Author Recognition Test and Title Recognition Test modulated by print exposure and academic background. Behavior Research Methods.
The supplimentary materials include the raw data for each test (ART, TRT, descriptives), an example questionnaire as handed to the participants and a list with the correct ART/TRT answers
Supplementary materials for ART and TRT in German
No full textSupplementary materials for:
Hug, Marion, Jarosch, Julian, Eichenauer, Christiane, Pennella, Selina, Kretzschmar, Franziska & Nicklas, Pascal (2024): Some students are more equal: Performance in Author Recognition Test and Title Recognition Test modulated by print exposure and academic background. Behavior Research Methods.
The supplimentary materials include the raw data for each test (ART, TRT, descriptives), an example questionnaire as handed to the participants and a list with the correct ART/TRT answers
Sex-linked transcriptional divergence in the hermaphrodite fungus Neurospora tetrasperma
No full textIn the filamentous ascomycete Neurospora tetrasperma, a large (approx. 7 Mbp) region of suppressed recombination surrounds the mating-type (mat) locus. While the remainder of the genome is largely homoallelic, this region of recombinational suppression, extending over 1500 genes, is associated with sequence divergence. Here, we used microarrays to examine how the molecular phenotype of gene expression level is linked to this divergent region, and thus to the mating type. Culturing N. tetrasperma on agar media that induce sexual/female or vegetative/male tissue, we found 196 genes significantly differentially expressed between mat A and mat a mating types. Our data show that the genes exhibiting mat-linked expression are enriched in the region genetically linked to mating type, and sequence and expression divergence are positively correlated. Our results indicate that the phenotype of mat A strains is optimized for traits promoting sexual/female development and the phenotype of mat a strains for vegetative/male development. This discovery of differentially expressed genes associated with mating type provides a link between genotypic and phenotypic divergence in this taxon and illustrates a fungal analogue to sexual dimorphism found among animals and plants
Nuclear interactions in a heterokaryon: insight from the model Neurospora tetrasperma
No full textA heterokaryon is a tissue type composed of cells containing genetically different nuclei. Although heterokaryosis is commonly found in nature, an understanding of the evolutionary implications of this phenomenon is largely lacking. Here, we use the filamentous ascomycete Neurospora tetrasperma to study the interplay between nuclei in heterokaryons across vegetative and sexual developmental stages. This fungus harbours nuclei of two opposite mating types (mat A and mat a) in the same cell and is thereby self-fertile. We used pyrosequencing of mat-linked SNPs of three heterokaryons to demonstrate that the nuclear ratio is consistently biased for mat A-nuclei during mycelial growth (mean mat A/mat a ratio 87%), but evens out during sexual development (ratio ranging from 40 to 57%). Furthermore, we investigated the association between nuclear ratio and expression of alleles of mat-linked genes and found that expression is coregulated to obtain a tissue-specific bias in expression ratio: during mycelial extension, we found a strong bias in expression for mat A-linked genes, that was independent of nuclear ratio, whereas at the sexual stage we found an expression bias for genes of the mat a nuclei. Taken together, our data indicate that nuclei cooperate to optimize the fitness of the heterokaryon, via both altering their nuclear ratios and coregulation genes expressed in the different nuclei
Nuclear interactions in a heterokaryon : insight from the model Neurospora tetrasperma
No full textA heterokaryon is a tissue type composed of cells containing genetically different nuclei. Although heterokaryosis is commonly found in nature, an understanding of the evolutionary implications of this phenomenon is largely lacking. Here, we use the filamentous ascomycete Neurospora tetrasperma to study the interplay between nuclei in heterokaryons across vegetative and sexual developmental stages. This fungus harbours nuclei of two opposite mating types (mat A and mat a) in the same cell and is thereby self-fertile. We used pyrosequencing of mat-linked SNPs of three heterokaryons to demonstrate that the nuclear ratio is consistently biased for mat A-nuclei during mycelial growth (mean mat A/mat a ratio 87%), but evens out during sexual development (ratio ranging from 40 to 57%). Furthermore, we investigated the association between nuclear ratio and expression of alleles of mat-linked genes and found that expression is coregulated to obtain a tissue-specific bias in expression ratio: during mycelial extension, we found a strong bias in expression for mat A-linked genes, that was independent of nuclear ratio, whereas at the sexual stage we found an expression bias for genes of the mat a nuclei. Taken together, our data indicate that nuclei cooperate to optimize the fitness of the heterokaryon, via both altering their nuclear ratios and coregulation genes expressed in the different nuclei.</p
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