Faculty of Agriculture and Forestry
Recent Submissions
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(2024)Saprotrophic wood-decaying fungi access nutritional carbon by degrading lignocellulosic biomass with ligninolytic and carbohydrate active enzymes. Research of species-species level interactions of the fungi is crucial to understand ecosystem functions and carbon cycling. Furthermore, research results of wood-decaying fungi and interspecific fungal interactions can be beneficial for development of biotechnological applications. In this study, two brown rot species Fomitopsis pinicola and Fomitopsis betulina, two white rot species Phlebia radiata and Fomes fomentarius and one soft rot species Schizophyllum commune were studied in combination cultures on birch wood substrate for 12 weeks. Interactions of the fungi were studied by analysing laccase, manganese peroxidase, xylanase, and iron reduction activities, and by analysing the expression of genes coding for lignocellulose-degrading enzymes. pH of the cultures was measured to estimate the metabolic activity of the fungal species. Suppression of xylanase and iron reduction activities demonstrated dominance of the white rot species over the other decay type species in the co-cultures. In addition to the depressed enzyme activities, increase in white rot production of laccase and manganese peroxidase activities indicated combative interactions in the co-cultures. This study evidenced species and growth-time dependent changes in signature enzyme activities and in gene expression of wood-decaying fungi during interspecific fungal interactions.
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(2024)Antimicrobial resistance (AMR) is a crucial problem in the clinical field worldwide. The need for novel antimicrobials to tackle AMR is imminent. Image-derived data can be used to understand the mechanism of action (MoA) of newly discovered compounds and classify them within known classes of antibiotics. This study aimed to develop a simple image-based measurement method for screening new antimicrobials and simultaneously defining the MoA. In the process, Escherichia coli ATCC 25292 was selected as a model strain from the Gram-negative bacterial group. This strain was treated with antibiotics belonging to different classes. Treated bacteria were imaged with Cytation 5 Cell Imaging Reader and analyzed using ImageJ2 software. The developed workflow was validated by testing the pipeline to be applied for some ESKAPE strains categorized as antibiotic-resistant bacteria. The results revealed that this pipeline enables us to observe the bacterial single-cell phenotypic changes in response to antimicrobials, such as the elongation caused by ampicillin and ciprofloxacin treatments, which are cell wall synthesis and DNA replication inhibitors, respectively. The treated bacterial cells were significantly longer than untreated cells from the sample without antibiotic. Thus, the image-based-high throughput assay can support the drug discovery by identifying the preliminary MoA of new antimicrobials against AMR bacteria. Promising data obtained on E. coli and some pathogenic bacteria allow for pursuing similar approach with other AMR Gram-negative bacterial species.
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(2024)Yksityiset metsänomistajat muodostavat merkittävän ryhmän metsäalalla Suomessa, sillä he omistavat yli puolet metsämaasta. Yksityiset metsänomistajat ovat myös tärkeä asiakasryhmä metsäteollisuudelle, sillä suurin osa metsäteollisuuden hankkimasta teollisuuspuusta on peräisin yksityismetsistä. Pysyvän asiakassuhteen varmistaminen tämän tärkeän sidosryhmän kanssa onkin tärkeää puunhankintaorganisaatiolle. Digitaalisten palveluiden merkitys metsänomistajille on kasvanut viimeisten vuosikymmenten aikana. Metsäalalla ei ole kuitenkaan tutkittu, mikä on digitaalisten metsänomistajapalveluiden merkitys yksityismetsänomistajien asiakaspysyvyyteen. Tämän tutkielman tavoitteena on selvittää yksityismetsänomistajien asiakaspysyvyyttä ja digitaalisten metsänomistajapalveluiden merkitystä asiakaspysyvyyteen. Tutkielma tehdään toimeksiantona suomalaiselle metsäteollisuusyrityksen puunhankintaorganisaatiolle. Tutkielmassa käytetään kvantitatiivista tutkimusmenetelmää ja tutkimusaineistona hyödynnetään tutkielman toimeksiantajan asiakastietojärjestelmästä kerättyä pitkittäisaineistoa. Asiakaspysyvyyttä seurattiin vuosina 2018–2022. Aineiston analyysimenetelminä käytettiin logistista regressioanalyysiä, ristiintaulukointia, khiin neliö - testiä ja riippumattomien otosten t-testiä. Tutkimustulokset osoittavat, että miesten asiakaspysyvyys on naisia parempi. Metsätilan sijaintikunnan ulkopuolella asuminen puolestaan heikentää asiakaspysyvyyttä. Metsäpinta-alan kasvu parantaa asiakaspysyvyyttä vain lievästi, mitä voidaan pitää yllättävänä tuloksena. Tarkastellessa digitaalisia metsänomistajapalveluita käyttäviä, voidaan todeta, että heillä on huomattavasti korkeampi asiakaspysyvyys kuin palveluita käyttämättömillä. Metsänomistajan iän kasvu on asiakaspysyvyyttä heikentävä tekijä digitaalisia metsänomistajapalveluita käyttävissä. Tutkielma tarjoaa lisää tietoa asiakaspysyvyydestä metsäalalla. Aineiston keruutavan vuoksi saatuja tuloksia ei voida kuitenkaan yleistää luotettavasti. Jatkotutkimuksissa asiakaspysyvyyttä voitaisiin tutkia pidemmällä ajanjaksolla. Lisää tutkimusta tarvitaan myös metsänomistajien näkemyksistä ja asenteista asiakaspysyvyyteen ja digitaalisiin metsänomistajapalveluihin liittyen.
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(2024)Wood construction has been increasing globally and engineered wood products (EWPs), such as Cross Laminated Timber (CLT), have had a major part in it. Increasing wood construction could help decrease the carbon footprint of the construction sector, since wood can be sustainably sourced and wood products store carbon. To use wood in construction in a more extensive way, its properties and behaviour as a construction material must be known. Wood has many properties of which moisture has a great impact on other properties, such as strength. Too high moisture can also cause problems, such as fungal growth, on its own. Therefore, it is important to monitor the moisture levels and understand the factors affecting them. In this study, the wood moisture content (MC) of CLT wall elements was monitored with resistance-based moisture meters from the manufacturing plant, through transportation and construction of a building at the Hyytiälä forestry station in Finland. There were sensors in five locations around the building and they all measured MC in three different depths inside the wall. The objective was to see how, where and when did the MC change within the CLT elements. The data was analysed with statistical tests and presented through various types of graphs. The results showed that variation within the data was large, approximately from 8% to 16%. On average the MC was at its highest near the surface of the CLT elements, after the protective canopy was removed. Two measuring locations on the opposite sides of the building had consistently higher MC than in the other measuring locations. The MC stayed below FSP (Fibre saturation point) throughout the monitoring period and, therefore, the risk for moisture induced damage is very low.
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(2024)Norway spruce (Picea abies) is one of the most economically important tree species in northern and central Europe. Root rot caused by Heterobasidion annosum s.l. and European spruce bark beetle (Ips typographus) are major disturbance agents of Norway spruce, and likely to have even greater impact on spruce-dominated forests as climate warms. This thesis investigated the direct interaction between Heterobasidion root rot and I. typographus. The aim was to examine if presence of root rot and the stress it poses to a tree increases the risk for subsequent bark beetle attack. 442 Norway spruce trees from nine different stands were measured and included in this study. Before the final felling, symptoms caused by I. typographus were evaluated from each tree based on visual assessments of crown and stem conditions. After the final felling, the sample plots were relocated from the clearcut areas, and the stumps of the sampled trees were re-assessed for Heterobasidion root rot. Exploratory analysis and binomial Generalized Linear Mixed Model (GLMM) were used to analyze relationships between different explanatory variables and their affect to I. typographus infestation. The best predictors for I. typographus infestation were incidence of root rot and to a lesser extent, decreased 5-year diameter growth and larger diameter at breast height. 75% of root rot infected trees were also infested with I. typographus, and the amount of root rot was considerably higher within dead and severely infested trees compared to alive and moderately infested trees. Results suggest that root rot is one of the significant factors making trees susceptible to I. typographus infestation, especially when the population density of bark beetles is low and stable. Thus, protecting trees from root rot infection may help to protect trees from I. typographus infestation as well.