| 91. |
- Ljunggren, Joel
(författare)
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Biochemical Interactions of Some Saproxylic Fungi
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Interactions are all around us, and as humans we may use words and gestures to communicate our intentions. At the micro level of fungi, communications are replaced by chemical signals and structure. These interactions fall into three distinctive categories: synergistic, where organisms help each other, as is the case with ectomycorrhizal fungi and tree roots, deadlock, or combat, where organisms fight for or defend a resource. When it comes to fungi-tree interactions, the fungi group of basidiomycetes fall into the latter category. At the onset of fungal infection, a living tree defends itself by producing resinous substances such as terpenes. These compounds are frequently found in hydrodistilled turpentine, which makes turpentine a prime source of antifungal compounds. A D-optimal design of fractionated turpentine together with gas chromatography (GC) coupled to a mass spectrometer was employed to find the most biologically active constituent of turpentine. Growth rate of Coniophora puteana was used to assess the efficacy of the mixed fractions. The partial least squares projection model had an excellent predictive power (R2 = 0.988, Q2 = 0.825) and validity. A putative sesquiterpene was identified as the most active compound for inhibiting fungal growth. The model was corroborated by an external validation assay employing preparative GC. After the death of a tree, fungi are no longer hindered by secondary metabolites from the tree. Instead, other interspecies interactions and intraspecies interactions, such as fungi-fungi interactions, occur. We found that when the white-rot fungus Heterobasidion parviporum and brown-rot fungus Gloeophyllum sepiarium interact with each other, amino acids are used to a higher extent. Amino acids may be used to produce antifungal compounds to hinder the other species from growing. Lysine in particular was utilized to a greater extent during interaction. Glutamine was the only amino acid that increased in concentration. Glutamine might be exuded or converted by enzymes from already existing glutamic acid. Dry weights suggest that the fungi were in a deadlock and that nutrient limitation might be a determining factor. It seemed that H. parviporum was favoured by a decrease in pH while the opposite pattern may be true for G. sepiarium.
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| 92. |
- Ljunggren, Joel, et al.
(författare)
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Changes in Extracellular Amino Acids, pH and Growth when Fungi Interact at the Near-contact Level: Heterobasidion parviporum vs. Gloeophyllum sepiarium
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Heterobasidion parviporum and Gloeophyllum sepiarium are fungal species representing two different ecological niches. H. parviporum is a parasitic white-rot fungus and early colonizer of felled wood, while the brown-rot fungus G. sepiarium is an early-middle colonizer in the natural fungi succession order. In this study, we quantitatively examined the utilization of amino acids in the μM range, pH and final dry weight from common liquid glucose-malt extract medium when the two fungi were interacting at the near-contact level. An increase in glutamine concentration was observed, and lysine was utilized in a greater extent when fungi were interacting compared to when they grew on their own. Our results also show fungal interaction is a process with high variability both in pH, growth and amino acid utilization, depending on the type of interaction. A connection between the growth, according to dry weight, and pH is suggested in the interaction between H. parviporum and G. sepiarium.
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| 93. |
- Ljunggren, Joel, et al.
(författare)
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Combinatorial Retention-Activity Relationship of Fractionated Turpentine on Fungal Growth
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Essential oils from plants are often used in growth inhibition assays against bacteria, fungi, insects and viral infections. Turpentine from Norway spruce (Picea abies) is an essential oil produced in large quantities as a waste product in paper production. It is a complex mixture of secondary metabolites that is rich in terpenes and terpenoids. These compounds protect the tree from fungal and bacterial infection; turpentine should therefore be a good source for biologically active substances for inhibiting fungal growth. In this study, a combination of a reductive and a holistic approach was employed to find the most inhibiting compound; an approach that we have called an intermistic approach. The most inhibiting compounds was determined in three steps against growth of the saproxylic fungus Coniophora puteana: rejecting half of the turpentine search space in a reductive manner, finding the optimal concentration and finally combining fractions of the most active half of turpentine in a quadratic D-optimal design to investigate it holistically. Multivariate data analysis of gas chromatography coupled with mass spectrometry (GC-MS) chromatograms was used to zoom in on the most active compounds responsible for antifungal activity. The growth rate of C. puteana in mm/day was used as y-variable and the relative area percentage of 36 GC-MS peaks from the mixtures was used as x-variables to construct a partial least squares (PLS) regression model. The final model was reduced to 12 peaks and used to find the most promising antifungal compound within the mixture. In addition, an external validation was performed with preparatory GC on the most active fraction. From the model, one putative sesquiterpene was identified along with at least two other sesquiterpenes and one diterpene warrant further investigation. Herein, a general method for finding biologically active compounds against wood-rotting fungi, and potentially other organisms from a complex mixture, is proposed.
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| 94. |
- Ljunggren, Joel, et al.
(författare)
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Evaluation of fractionally distilled Picea abies TMP-turpentine on wood-decaying fungi : in vitro, microcosm and field experiments
- 2020
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Ingår i: Wood Science and Technology. - : Springer Science and Business Media LLC. - 0043-7719 .- 1432-5225. ; 54, s. 847-868
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Tidskriftsartikel (refereegranskat)abstract
- Synthetic and heavy metal antifungals are frequently used as wood preservatives. However, they exhibit relatively inert biodegradation and toxic properties when leached; this makes their replacement with environmentally degradable yet functional alternatives a key target in the wood protection industry. In this context, distilled fractions of raw thermomechanical pulp turpentine (TMP-T) from Picea abies were assessed for their wood protecting capabilities against wood-decaying fungi. Antifungal bioactivity of fractions and some of their combinations were screened on agar-plates against the brown-rot fungus Coniophora puteana. Addition of TMP-T fractions showed a significant fungal growth rate reduction, while mixtures indicated the presence of synergistic and antagonistic effects. One fraction, obtained after distilling 1 L TMP-T at 111–177 °C at 0.5 mbar, showed complete growth inhibition of Antrodia sinuosa, Serpula lacrymans, Serpula himantioides and significant inhibition of Antrodia serialis, Antrodia xantha, Gloeophyllum sepiarium, Heterobasidion parviporum at a concentration of 1000 ppm. This fraction was further examined for long- and medium-term effects on wood decay in microcosm soil-jar and field experiment, respectively. The known antifungal compounds benzisothiazolinone, 2-octyl-4-isothiazolin-3-one, 3-iodo-2-propynyl N-butylcarbamate and two commercial wood preservatives were used as reference treatments. Commercial preservatives instilled long-term efficacy against C. puteana wood decay in a soil-jar microcosm experiment, but no noticeable protection with antifungal compounds or the present treatments was found. However, a moderate effect by the TMP-T fraction from the in vitro assay was observed and the TMP-turpentine distillation residue showed a similar fungal inhibition effect to the most potent commercial treatment after 29 months in the field.
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| 95. |
- Ljunggren, Joel
(författare)
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Some Approaches to Eco-Friendly Products from Natural Matrices
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Since the onset of the industrial and chemical revolution, humans have caused immense damages to the surrounding flora and fauna. Effective methods for wood protection measures proved to be toxic; fossil fuels contribute to global warming and pesticides can be detected in the air, water, and soil. It is abundantly clear that efforts to find eco-friendly products are needed, while simultaneously providing the necessary incentives for sustainable worldwide development. Using renewable resources play a critical role in this shift towards circular economies.Wood has long been used as a renewable resource in high demand, but its susceptibility to attack by wood-decaying fungi mean that most European woods need to be protected against these fungi before outdoor use. We showed that fractionating turpentine, a pulp and paper mill by-product, increased antifungal efficacy by concentrating bioactive oxygenated sesquiterpenes. Based on this result, recombinations of the fractions were shown to exhibit synergistic effects that enable a more efficient product utilisation. In addition, this approach enabled putative identifications of previously unknown Picea abies turpentine constituents present at low levels.For a carbon-neutral society, production of biofuels using oleaginous yeast to convert lignocellulosic biomass into fuel has been hailed as a next-generation source of bioenergy. However, lignocellulose biofuel production by microorganisms is not straightforward and one challenge is the formation of microbe-toxic monomers, such as vanillin, during lignin degradation. The oleaginous yeast Cystobasidium laryngis and other potential oil-producing yeasts were screened for their viability and vanillin biotransformation capabilities. To this end, a mass chromatographic peak extraction tool termed TMATE was developed. Vanillyl alcohol was found to be the main product following vanillin degradation.The detrimental health and ecological effects of pesticides highlight the urgency for alternative crop protection measures, such as biological insect control and semiochemicals. In this regard, we present an essential step towards understanding the varied chemical ecology of microbe-insect interactions. Our methodology and findings provide cues with high information value that can be used to develop well-informed and potentially sustainable pest management regimes by, for example, the push-pull methodology using live yeasts.
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| 96. |
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| 97. |
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| 98. |
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| 99. |
- Lyytikäinen-Saarenmaa, Päivi, et al.
(författare)
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Monitoring European pine sawfly population densities with pheromone traps in young pine plantations
- 1999
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Ingår i: Forest Ecology and Management. - 0378-1127. ; 124:2-3, s. 113-121
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Tidskriftsartikel (refereegranskat)abstract
- Field trials utilizing pheromone traps were evaluated to develop a population monitoring and predicting system for the European pine sawfly (Neodiprion sertifer). Larval density was censused in a transect across each study site. Three traps per site were baited with 100μg of (2S,3S,7S)-3,7-dimethyl-2-pentadecyl (diprionyl) acetate. During a two-year period traps loaded with 1, 10 and 100 μg of diprionyl acetate were compared. Correlations and coefficients of determination between numbers of captured males and larvae of the same or successive generations were seldom high. Between-generation relationships were significant, when population density was increasing. Having years with increasing densities in a row, the present monitoring method might provide warning of an outbreak.
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| 100. |
- Lyytikäinen-Saarenmaa, P, et al.
(författare)
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Monitoring the European pine sawfly with pheromone traps in maturing Scots pine stands
- 2006
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Ingår i: Agricultural and Forest Entomology. - : Wiley. - 1461-9555 .- 1461-9563. ; 8:1, s. 7-15
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Tidskriftsartikel (refereegranskat)abstract
- 1. During 1989-93, field studies were conducted in Finland to develop a method based on pheromone traps to monitor and forecast population levels of the European pine sawfly (Neodiprion sertifer Geoffr.) and tree defoliation. 2. Three traps per site were baited with 100 μg of the N. sertifer sex pheromone, the acetate ester of (2S,3S,7S)-3,7-dimethyl-2-pentadecanol (diprionol), in maturing pine stands in southern and central Finland. In addition, three different dosages (1, 10 and 100 μg) of the pheromone were tested in 1991-92. 3. The highest number of males was observed in traps baited with the highest dose. On average, there was a 10-fold increase in trap catch between lure doses. 4. Density of overwintering eggs was used to evaluate the effectiveness of pheromone traps in predicting sawfly populations. The proportion of healthy overwintering eggs was determined each year. A model based on the number of current shoots on sample trees, diameter at breast height and tree height was formulated to estimate eggs per hectare. 5. Linear regression analysis produced high coefficients of determination between number of males in traps and density of total eggs in the subsequent generation, when populations were at peak densities. The relationships were not significant for low population densities. The results indicate a risk of moderate defoliation when the seasonal trap catch is 800-1000 males per trap or higher.
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