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  • Castellazzi, Eugenia (2023)
    Tiivistelmä - Referat - Abstract To aim for a just and sustainable society, it is essential to consider how we manage cities and to reflect on the role of young people as agents for successful future generations. The school system must take on the responsibility of developing a sense of social justice amongst young people. However, few learning activities are established to promote learning about environmental and intergenerational justice issues, and are usually limited to a top-down approach based on STEM disciplines (Science, Technology, Engineering and Mathematics). In this work, I argue that education in sustainability needs to be opened to a relational approach that introduces new justice perspectives, becoming a driver for active citizenship and public participation. The thesis is based on ten workshops conducted in Kumpula, Helsinki, involving 197 students from two upper secondary schools. The novelty of this work consists in addressing a specific range of upper secondary school students (16 to 19) and combining cognitive and relational learning activities to elicit reflections on environmental justice. I used a learning activity based on a Role-play method to actively involve students in working with justice perceptions and nature-based solutions. The analysis is based on a mixed methods- approach where the statistical analysis (pretest-posttest) and qualitative content analysis support each other. The innovative integration of cognitive and relational learning contributed to a deeper knowledge of urban green space management. This approach elicited new recognition justice perspectives by enhancing the participants’ awareness of community values and needs, comprehending both humans and non-humans. After the learning activity, students were generally more willing to make their voice heard by policy makers and to participate in public discussions. Based on the findings, more resources and time would be needed to build a long-term project in order to assess the permanence of relational and cognitive learning and more widely the efficacy of this approach for transformative learning.
  • Salciute, Martyna (2024)
    Lynch syndrome is the most common hereditary colorectal cancer (CRC) syndrome caused by inherited mutations in DNA mismatch repair genes. Of those, MLH1 is the most mutated predisposition gene and is best known for its involvement in the DNA mismatch repair (MMR) pathway. In addition to the MMR, MLH1 has proved to have a multifunctional role in assisting in the maintenance of genomic stability. Emerging evidence suggests, that reduced levels of MLH1 directly contribute to an increased number of DNA double-strand breaks (DSBs), leading to chromosomal instability (CIN) through impaired mitochondrial function and homologous recombination directed DSB repair. This study aimed to test this hypothesis by evaluating the DNA damage status and mitochondrial functionality in MLH1 knock-down (KD) fibroblast cell lines with varying expression levels of MLH1. DNA damage levels and repair kinetics were inspected by implementing the Comet assay. Moreover, mitochondrial homeostasis examination was done by utilizing functional mitochondrial staining and analysing mitochondrial DNA copy number. Although there was variability in the results, two KD cell lines exhibiting 30% (line 3A3) and 40% (line 2B7) MLH1 expression levels showed similar outcomes: decreased mitochondrial membrane potential, increased cellular reactive oxygen species (ROS) and stalled DNA damage repair as compared to control cell lines, suggesting the involvement of MLH1 deficiency. It is known, that MLH1 depletion predisposes to DNA damage due to impaired MMR. The findings of this thesis contribute to the growing body of evidence, suggesting that MLH1 deficiency may increase the propensity for DNA DSBs, possibly due to impaired mitochondrial function and subsequent elevation in cellular ROS. Furthermore, this increase in DNA breaks may result in CIN. However, given the limited sample size, the results warrant future studies with larger datasets.
  • Uriona Egia, Garazi (2023)
    The ends of eukaryotic chromosomes are formed by a special heterochromatic structure, the telomere, which is essential to guarantee chromosome stability. Telomeres protect chromosomic ends from DNA degradation, repair, and recombination events. However, they are difficult to replicate due to their repetitive and heterochromatic nature, which hinder DNA replication fork progression. In yeast, Mph1 helicase promotes replication fork regression, cross-over suppression during homologous recombination (HR), and telomere maintenance. Moreover, Mte1 is a D-loop binding protein involved in response to DNA damage and maintenance of telomere length, which interacts with Mph1, thereby stimulating its regression capacity as a helicase and fork. Thus, the Mte1-Mph1 complex is recruited to stressed telomeres. Mte1 also shares a domain of unknown function, DUF2439, with Rad51 and Rdh54. Additionally, Esc2 protein is involved in the regulation of DNA damage through template switch (TS) recombination, preventing HR events caused by Mph1. This thesis aimed to uncover the potential roles and interactions of proteins involved in telomere maintenance, such as Mph1, Mte1, Esc2 and Rdh54, for which two main assays were conducted: (1) Telomere Stability assay, consisting of Tus/Ter barrier based on the high-affinity binding of the E. coli protein, Tus, to specific DNA sequence called Ter; (2) Template Switching assay, focused on the capability of the proteins in reconstructing a functional LYS2 gene by TS. The obtained results demonstrated that (1) the absence of Rdh54 enhances replication fork regression, (2) Mte1 and Esc2 show opposite roles in telomere maintenance, (3) the interaction between Mte1 and Rad51 plays a crucial role in ensuring telomere stability and nuclear foci formation, (4) Mph1 and Mte1 promote cell survival through the break-induced replication (BIR) pathway. Further studies should assess the plausible interaction between Mph1 and Rdh54 proteins and characterize the function and interplay of the proteins involved in TS.
  • Kõbin, Mihkel (2020)
    Intersectins (ITSNs) are important scaffold and adaptor proteins that play an important role in various cellular processes such as endocytosis. Although we know a lot about their function, there is little information on the regulation of these proteins. On the other hand, microRNAs have been shown to have an extensive function in regulating numerous genes in animals and their dysfunction is credited for down regulation of many proteins. In this study, I demonstrate that microRNAs are potential regulators of ITSNs in HEK293 cells and human neuronal cell cultures. In this study, I cloned 3’UTRs of different isoforms of intersectins (ITSNs) and microRNAs to the expression vectors to express them in cells. I then transfected HEK293T or neuronal stem cell line (HEL47.2) with the constructed vectors and used various methods to analyse the effect of microRNAs on the expression of ITSNs. The main methods I used were dual-luciferase assay, reverse transcription quantitative PCR and western blotting, human neuronal stem cell culturing and lentiviral transduction. My results demonstrate that there were two microRNAs that stood out from other and had a significant downregulation of ITSNs mRNA levels in HEK293T cells. Those were miR-124 and miR-19. However, in the human neuronal cell line I did not observe a significant alteration of the ITSNs transcript level. Additionally, I suggest that the given microRNAs regulate protein levels by promoting the decay of the ITSN transcripts. However, more studies are needed to show a stronger causative effect of microRNAs on ITSNs. Subsequent studies should also look at how multiple microRNAs can influence gene expression cooperatively.
  • Lammensalo, Linda Sofia (2021)
    The intersections of climate change and sexual and reproductive health and rights (SRHR) have increasingly received attention from international organisations but also from academia. For some, establishing these intersections is about reducing human pressure on the Earth systems, while for others it is about the human rights of vulnerable individuals and communities. Many have lauded these connections for providing a win-win solution for both. While these benefits are championed, there has been little reflection on the underlying motives and justifications for establishing these connections in the first place. Given the problematic past of population control policies, understanding these justifications is necessary to break away from the neo-colonial practices of the past. This thesis investigates the motives and justifications for establishing such intersections between SRHR and climate change. Specifically, the thesis addresses two questions, namely: 1) In what ways are the interconnections between SRHR and climate change justified in academic literature? 2) What are the implications of the ways in which these interconnections are justified? By drawing on a postcolonial feminist theoretical framework rooted in understanding this nexus critically, and carefully reflecting on the implications of these discourses, the thesis answers these questions by systematically drawing on a sustained body of research. The data consist of 88 academic publications that are systematised through discourse analysis. The findings identify six distinctive intersectional discourses which reflect the ways in which SRHR, and climate change are justified, namely: public health, population dynamics, reproductive rights, critical, sustainable development and environment discourses. Largely reflecting adherence to liberal feminist and populationist frameworks, these findings imply that the discourses, justifications, and motives do not sufficiently address the neo-colonial practices and structural inequalities that shape intersections between SRHR and climate change. Analytically, therefore, this thesis suggests that postcolonial feminism offers a more effective way for understanding intersectional discourses because it recognises how power inequalities manifest in the discourses, while contributing towards more justice-based approaches to sustainability.
  • Donner, Jalmar (2020)
    Climate warming is expected to cause changes in winter conditions in northern regions. These changes include reduced depth and duration of the snow cover, and strong fluctuations in winter temperatures. A mesocosm experiment was planned to study the short term effects of contrasting winter conditions, and an introduced species (garden lupin; Lupinus polyphyllus), on chlorophyll fluorescence and pigment concentrations of native meadow species in southern Finland. Twelve different meadow species, representing different overwintering strategies were planted in each mesocosm at the beginning of summer in 2016 in Viikki, Helsinki. One year later, a lupin was planted in half of the mesocosms. Over the winter 2017-18, one half of the mesocosms was moved to Nåtö on the Åland islands, and the other half was moved to Lammi, Hämeenlinna. To each site, both lupin-containing mesocosms and lupin free controls were moved. In the inland site in Lammi, the mesocosms spent the winter covered by a thick snow cover that isolated them from harsh air temperatures from beginning of December to end of March. In coastal Nåtö, a thin snow cover formed in January and melted by mid-March. In the experiment, the maritime winter climate on Nåtö represented such winter conditions that are expected to be common on the mainland in the future, when climate warming progresses. Leaf chlorophyll fluorescence as well as concentrations of leaf chlorophyll and flavonoids were repeatedly measured nondestructively for all species using optical apparatus. Growth and flowering of the lupin was monitored during spring and summer 2018. No marked differences were observed in the meadow species chlorophyll fluorescence and content between sites, indicating that these are well adapted to variable winter conditions. The flavonoid composition of the meadow species seemed to be regulated by seasonal changes in light intensity and temperature. Small reductions in chlorophyll content for some species indicated that these were disadvantaged by the lupins presence. This was attributed to the lupins shadowing effect. In contrast, two evergreen species seemed to take advantage of the nitrogen input from the lupin in terms of higher chlorophyll content in summer 2018. The lupin overwintered successfully in mainland Lammi, but seemed to suffer from the maritime and snow poor winter conditions in Nåtö, which led to reduced production of leaves and inflorescences during the growing season 2018. The results indicate that native meadow species in Finland are relatively tolerant of the expected changes in mainland winter conditions, whereas these changes will be disadvantageous for the lupin.
  • Mäkiö, Elisabeth (2024)
    This thesis explores the political decision-making process related to a cancelled PV park development in the city of Järvenpää, Finland. A PV park planned by the energy company Helen in Järvenpää was cancelled due to city council’s opposition of the project. Serving as an illustrative case study, this thesis highlights the political process, discourses and arguments used from both by the supporters and opponents of the project in the city council. This thesis sets out to explore how different political agents operate in the decision-making process regarding energy projects, and which factors, including whose voices, influence their behaviour. By utilising semi-structured interviews with local Järvenpää city councillors, as well as publicly available materials, including opinion pieces and council’s records, this thesis analyses the discourses and arguments used in this local political decision-making process. Using the framework of energy justice and evaluating the discourses and arguments put forward by the supporters and opposers of the project, this thesis shows three crucial differences discourses about the planned PV park put forward by the local politicians, which relate to the different arguments made for or against the park. These three discourses are broadly categorised as: The Nature of the PV Park; The Participation of Residents; and Political Positionalities. The opponents and supporters of the project put forward fundamentally different arguments about the nature of the PV park, as well as of the current nature of the space without the park. The negative reaction of the residents was also seen differently, as either organic resistance or as politically manufactured. Pre-existing political positionalities were used by both parties as explaining factors of the others’ behavior and beliefs, either due to ideological “obsession” or populism. Additionally, the high socio-economic status of the nearby residents was brought up as a significant factor. These findings connect to previous literature, by showcasing that financial incentives are not always enough to gain approval of energy development projects as well as questioning whether a public hearing is enough to guarantee procedural justice if the voices of high-ranking socio-economic group members dominate over others.
  • Levo, Martti (2023)
    Climate change is applying pressures to plant populations, which must adapt or move to retain fitness. A changing climate highlights the need for us to understand the potential that species possess to evolve in addition to any plastic responses. Approaches that allow the study of contemporary evolution, such as resurrection studies, have the capacity to provide insights into the responses of populations to these changes. In this resurrection experiment, seeds from seven populations of Hypericum perforatum collected from the UK and France, and their historic counterparts, were grown and subjected to four temperature treatments. Three traits were measured and compared between historic and contemporary populations: date of flowering, average seed weight and flower abundance. I found that temperature influenced date of flowering and flower abundance, leading to an overall earlier flowering time and an overall decrease in flower abundance with increase in temperature. The only significant difference between historic and contemporary populations was found in flower abundance - where, whilst flower abundance declined with increasing temperature, contemporary populations produced proportionally more flowers than historic populations per degree of temperature increase. These results suggest that plasticity allows this species to adjust its flowering phenology to retain fitness in warmer conditions but that evolution during the past decades may have selected for a decreased flower abundance at higher temperatures. These findings contribute to our overall understanding of how species have and will react under climate change, as we try to disentangle the roles that plasticity and evolution play in enabling populations to retain fitness under changing conditions.
  • Turunen, Ossi Artturi (2022)
    Life-history decisions, and trade-offs, are affected by resource acquisition, which can vary among individuals, and during the life cycle of an individual. In Atlantic salmon (Salmo salar) many life-history decisions, such as age-of-maturity, are strongly associated with two genomic regions, vgll3 and six6. Previously, these genomic regions have been associated with food acquisition in adult sea-run Atlantic salmon; however, this has not yet been studied in juvenile salmon. Furthermore, population density strongly affects the food availability of juvenile salmon through resource competition. Here, using controlled crosses reared in semi-natural stream conditions, I investigated the effect and relationship of life-history genetics and population density on juvenile Atlantic salmon food acquisition. Stomach contents from 148 juvenile Atlantic salmon were quantified for their prey item composition, total number of prey items and dry weight, and environmental and genetic basis of food acquisition were analysed using mixed effects models. Late maturing six6 genotype fish had higher stomach-content dry weights and fuller stomachs than early maturing individuals, in low densities. Furthermore, low density fish were of better condition and had higher growth rates than high density fish. There was no association between six6 and vgll3 genotypes and food acquisition in high densities. The results support the existing knowledge of the negative effect of increasing population density on juvenile Atlantic salmon growth and condition. Furthermore, the density dependent association of six6 and food acquisition suggest a trade-off between early maturation and maximised food acquisition.
  • Fischbach, Lea (2022)
    Establishing and maintaining cell polarity is critical to all multicellular organisms. Apicobasal polarity is a type of cell polarity specific to epithelial cells, which is established and maintained by three distinct protein complexes. Among them, the Scribble (Scrib) complex plays a role as a basolateral determinant. Scrib is a scaffold protein with multiple functions, including maintenance of the basolateral polarity of epithelial cells and a tumor suppressor, acting as a regulator of the Hippo signalling, an evolutionarily conserved pathway which controls organ size through regulation of cell proliferation and apoptosis by inhibiting the transcriptional co-activator protein Yorkie (Yki). A recent experiment proposed that Scrib is involved in maintaining tissue homeostasis through relaying apicobasal polarity regulation across the tissue. This mechanism can be used both by normal cells to rescue hypomorphic scrib cells and by loss of scrib cells to spread loss of polarity. The signal is likely related by cell-cell contact and the junctions present in epithelial cells may be involved in this communication. This project aims to identify the genes involved in tissue homeostasis through intercellular alignment of apicobasal polarity together with Scrib. First, a screening protocol was established by studying genetic interactions and tissue structure. Second, a systematic screening was carried out by using deficiency lines of left arm of the third chromosome in Drosophila. Fly stock expressing spatially and temporally controlled scrib RNAi was established and crossed with deficiency lines to identify genes that have synergy with Scrib. The wing discs of the offspring were dissected, imaged, and the phenotypes were sorted into categories according to the degree of overgrowth. Five strong candidates and four candidates with milder phenotype were identified. The results show the screening method is robust and suitable to carry out a finer, single gene level screen of the candidates, as well as screening for additional candidates in the rest of the Drosophila genome. The identified candidates provide new leads to develop the theorical model of intercellular alignment of apicobasal polarity. Understanding how apicobasal polarity is maintained in the dynamic environment of a living organism is important for physiological and pathological conditions. This study provides an important insight into further understanding tissue development and homeostasis.
  • Ozaki, Tomoka (2024)
    This thesis explores the relationship between neuropathic pain and the circadian clock through the investigation of GSK4112 administration to a mouse model of neuropathic pain. Neuropathic pain, arising from a lesion or disease of the somatosensory system, historically posed treatment challenges due to narrow research approaches focusing solely on the pain system. Recent insights highlight connections between neuropathic pain and the circadian clock, including circadian rhythmicity in neuropathic pain and shared genetic expressions and pathways. The study aimed to investigate the effects of GSK4112, an agonist of Rev-erbα and a small molecule modulator of the circadian clock. This was done through a blinded experiment design in mice modelling neuropathic pain induced by spared nerve injury. The study involved tracking locomotive activity to assess alterations in circadian rhythm and infer effects on the circadian clock. In addition, behavioural tests that measure mechanical and thermal sensitivity were employed to investigate the potential analgesic effects of GSK4112 administration. As a result, no change to circadian activity or mechanical and thermal sensitivity was observed as a result of GSK4112 administration to mice with spared nerve injury.
  • Ruuska, Janika (2022)
    Individuals suffering from anorexia nervosa (AN) have one of the highest mortality rates of all psychiatric disorders, as a consequence of health complications that follows severe malnutrition. The impairments in cognitive flexibility, including an extreme focus on restricting food despite a rapid decline in body weight in AN, also plays an important role in the development of the disorder and has been suggested as a hallmark of AN. This cognitive inflexibility, common among many psychiatric disorders such as depression and obsessive-compulsive disorder, is linked to alterations in serotonin (5-HT) signaling in the medial prefrontal cortex (mPFC). Reduced 5-HT2A receptor activity and potentially increased 5-HT1A receptor activity are evident in the mPFC in individuals with AN and may be linked to impaired cognitive flexibility, however, the mechanisms through which 5-HT and inflexibility interact in AN are not fully understood. A better understanding of this link could pave the way toward more effective pharmacological treatments for AN. Psilocybin, a psychedelic compound produced by so-called “magic” mushrooms, has a high affinity for several 5-HT receptor subtypes including 5-HT1A and 5-HT2A receptors, and has now been empirically demonstrated to increase cognitive flexibility in individuals with major depressive disorder (MDD). In this study, we sought to understand how the development of pathological weight loss and/or psilocybin administration influenced the expression of RNA molecules of 5-HT2A and 5-HT1A receptors expression in the mPFC of rats. To this end, we used the activity-based anorexia (ABA) model, the only experimental model known to elicit voluntary reductions in food intake and voluntary hyperactivity that leads to rapid body weight loss in the majority of animals exposed to ABA conditions. Outcomes were compared against an age-matched control group that were not exposed to the ABA paradigm. Animals were administered psilocybin (1.5 mg/kg) or saline (control) and 4-10 days later brain tissue was collected for processing. Receptor expression was detected using a novel multiplex RNA fluorescent in situ hybridization (FISH) technology, RNAscope®. The main aim of this study was to examine changes in the expression of RNA molecules of 5-HT2A and 5-HT1A receptors in the mPFC elicited by ABA conditions and determine whether these were ameliorated by the administration of psilocybin. We found that animals exposed to ABA demonstrated a significant reduction of 5-HT2A receptors’ RNA levels in the mPFC, and that this was not influenced by psilocybin treatment. There have been reports from clinical trials that individuals with AN experience “less than expected” subjective effects from psilocybin, which may be explained by reduced expression of RNA molecules of 5-HT2A receptors in the mPFC, and is supported by our results in rats. Taken together, these results highlight a specific serotonergic mechanism that could underly the development of pathological weight loss and offers insight into possible issues with the therapeutic application of psilocybin for AN. Future studies will need to examine the effects of psilocybin during a more acute period following treatment to define these effects. Moreover, whether or not the reduced 5- HT2A receptors’ RNA level expression induced by ABA is restored with body weight recovery should be determined.
  • Ranki, Jukka-Pekka (2020)
    Loisten vaikutus isäntäpopulaatioihin ja isäntäyksilöiden elinkiertoon vaihtelee isäntä–lois-suhteittain. Loisten leviämistä ja vaikutuksia isäntäpopulaatioissa on kuvattu erilaisilla matemaattisilla malleilla, joissa on keskitytty joihinkin loisen yleistymisen kannalta olennaisiksi arvioituihin tekijöihin, kuten loisen transmissioon ja isäntien kuolleisuuteen, syntyvyyteen ja vastustuskykyyn. Mallien taustaoletukset ja painotukset vaihtelevat. Isäntä–lois-suhteiden muodostumisen taustalla onkin monia vaihtoehtoja tai syitä, joita on hyvä selvittää. Isäntä–lois-suhteiden muodostumista ja loisen leviämistä voidaan tarkastella myös ohjelmallisesti esimerkiksi simulaatioilla, joilla voidaan selvittää eri tekijöiden tai parametrien arvojen vaikutusta loisintaan. Simulaatio voi mallintaa loisintaa isäntäpopulaation tasolla ja kuvata tartunnan leviämistä isäntäpopulaatiossa eri hetkinä. Se voi mallintaa loisintaa myös yksilötasolla, jolloin siinä voidaan huomioida eri tavoin yksilöön liittyviä ominaisuuksia, kuten yksilön liikkumista tai parinvalintaa. Tällaisten isäntäpopulaation ja loispopulaation yksilöiden suhteita, sijainteja ja tilanteita eri hetkillä mallintavien ohjelmien suunnittelun tueksi on hyödyllistä luoda käsitteellinen malli, joka kuvaa loisintaa yksilötasolta lähtien samalla selventäen isäntien ja loisten ominaisuuksia ja loisintaan liittyviä vuorovaikutussuhteita. Tutkimuksen tavoitteena olikin luoda loisintasuhteita yleisesti kuvaava käsitteellinen malli. Tutkimuksen aineisto muodostui loisinnan biologiasta ja siihen kytkeytyvistä ilmiöistä. UML-mallinnuskieltä (Unified Modeling Language) käytetään yleisesti oliopohjaisten ohjelmistojen suunnittelussa ja järjestelmien kuvauksessa. Loisintaakin voi tarkastella isäntien ja loisten välisenä järjestelmänä, jossa loisinnan osapuolet ovat olioita. Menetelmänä käytinkin UML-luokkakaavioita. Tutkimus selvittää isäntä–lois-suhteiden olennaisia piirteitä ja muodostaa niiden pohjalta loisintaa yksilötasolla yleisesti kuvaavan UML-luokkakaavion. Osoittautui, että ’tavanomaisen’ loisinnan, jossa loinen elää kiinni isännässään hyödyntäen sitä ravintolähteenään, sekä kleptoparasitismin tai sosiaalisen loisinnan yhdistäminen samaan UML-luokkakaaviomalliin saattaa johtaa tulkinnallisiin epäselvyyksiin. Osoittautui myös, että isäntä–lois-suhteisiin liittyy erilaisia vuorovaikutuksia ja ilmiöitä esimerkiksi loishyökkäysten torjunnan osalta. UML-luokkakaaviomallista jäi pois muun muassa isännän loisintaa ehkäisevä käyttäytyminen, jotta mallin rakenne säilyi selkeänä. Isäntä–lois-suhteisiin liittyvät myös eliöiden liikkuminen ja lisääntyminen, jotka vaihtelevat lajeittain ja kehitysvaiheittain. Niitä voi tarkastella omina malleinaan, jotka kytkeytyvät loisinnan osapuoliin tai niiden kehitysvaiheisiin. Loisinnan osapuolten suhteisiin liittyy koevoluutiokin. Nopeasti ja runsaasti lisääntyvillä ja muuntuvilla mikroloisilla evoluutio voi olla nopeaa. Kuitenkin evoluutiota tarkasteltaessa pitäisi tietää, mitä mallinnetaan ja mitä rajoituksia evoluution mallinnukseen sisältyy. UML-luokkakaaviossa ei mallinnettukaan evoluutiota, vaan se vaatisi tarkempaa analyysia.
  • Ahovuo, Aura Elina (2020)
    Isolating mechanisms of the species usually prevent interspecific hybridisation. At times, these mechanisms might break down temporarily and lead to the birth of interspecific hybrids. Introgression is a term related to a set of consecutive backcrossings in which the hybrids reproduce with one of their parental species. It is characterised as a long process associated with alleles which are transferred from a population of one of the parental species to a population of the other parental species. Introgression is adaptive if phenotypic variation is increased in the recipient population by the genetic variants of the donor population and maintained by natural selection. The Baltic grey seal (Halichoerus grypus) and the Baltic ringed seal (Pusa hispida botnica) have interbred when they were kept in captivity in a shared pond. According to the findings from a previous study, interbreeding could have happened in the wild as well. The purpose of this study is to examine the proportion of introgression between the Baltic grey and ringed seals. The genomewide introgression is analysed using Patterson’s D-statistic, F4-ratio test and specific introgression intervals defined from the seals of analysed data. Introgression is assumed to have contributed intraspecific morphological variation detected in phocine teeth. Therefore, it is also examined whether the genes involved in tooth development express signs of introgression in the grey and ringed seals and whether the introgression intervals include potential variants. The results of Patterson D-statistic and F4-ratio test show both hybridisation and introgression between the Baltic grey and ringed seals. Based on the introgression intervals, a longer period has passed since the species interbred. Similar proportions of introgressed DNA as those defined from the genomes of the ringed seals have been detected in brown bears, bovines and modern humans. Furthermore, several genes affecting the shape of a developing mammalian tooth show signs of introgression in the seals. The individuals also carry variants in their introgression intervals. Introgression and the variants can account for the intraspecific morphological variation in the phocine dentitions. Potential introgressed genome intervals in the regulatory sequences of the tooth genes might also affect phocine tooth shape, which should be examined more in the future.
  • Eskola, Aino-Inkeri (2015)
    Panssarisiimalevät ovat suuri, morfologisesti ja ekologisesti monimuotoinen kasviplanktonryhmä.Panssarisiimalevien tuntemus on painottunut suurikokoisiin, yhteyttäviin ja laboratoriossa kasvatettaviin lajeihin, jaerityisesti pienten hetero- ja miksotrofisten panssarisiimalevien monimuotoisuus tunnetaan puutteellisesti. Itämerion maantieteellisesti ja ekologisesti eristynyt merialue. Panssarisiimalevien suhteellinen osuus Itämerenkasviplanktonista on kasvanut viime vuosikymmeninä. Tunnistamisen vaikeuden vuoksi Itämerenkasviplanktonseurannoissa pienikokoiset panssarisiimalevät kuitenkin usein sivuutetaan tai niitä käsitellään yhtenä,vain lahkotasolle määriteltynä ryhmänä. Pfiesteriaceae-heimon lajit ja Karlodinium veneficum ovat pienikokoisiahetero- ja miksotrofisia, mahdollisesti toksisia, haitallisia leväesiintymiä muodostavia panssarisiimaleviä. Näistäpanssarisiimalevistä ei ole vahvistettuja havaintoja Itämerestä. Lajeja pidetään kosmopoliittisina ja niidenasettuminen Itämeren murtoveteen on mahdollista. Tutkimukseni tavoite on selvittää pienikokoisten (alle 20 μm)panssarisiimalevien monimuotoisuutta Itämeressä ja arvioida näiden panssarisiimaleväkantojen suhdetta kantojenmuilta merialueilta eristettyihin lajitovereihin. Aineisto kerättiin Hankoniemen itäpuolelta Tvärminnen eläintieteellisen aseman läheisyydestä ja AhvenanmaanFöglöstä matalista ja suojaisista lahdelmista. Vesinäytteistä eristettiin kuoppalevylle valomikroskoopin avullapieniä (alle 20 μm) panssarisiimaleviä puhdasviljelmiä varten. Menestyksellisesti eristettyjäpanssarisiimaleväkantoja kasvatettiin Itämeren murtoveteen valmistetussa f/2-Si-kasvatusliuoksessa. Tiheiksikasvaneista soluviljelmistä eristin DNAn ja selvitin kantojen suku- ja lajitason identiteetin sekvensoimallaribosomaalisen DNAn SSU-, LSU- ja ITS-alueet. Tutkimuksessa luotujen sekvenssien ja GenBank-tietokannastaladattujen sekvenssien avulla laskin aineistosta neljä fylogeneettistä puuta. Kuvasin havaitut lajit morfologisestipyyhkäisyelektronimikroskoopilla. Toksisuusanalyysejä varten suodatin panssarisiimaleväkannoista näytteetlasikuitusuodattimille, jotka lähetettiin tutkittaviksi Yhdysvaltoihin. Tutkimuksessa eristetyistä 512 panssarisiimalevästä 100 kantaa jakautui kuoppalevyillä. Lopullisiin analyyseihinvalikoitui 12 kantaa. Fylogeneettisten ja morfologisten analyysien perusteella Itämerestä eristetyt kannat kuuluvatCryptoperidiniopsis brodyi-, K. veneficum- ja Pfiesteria piscicida-lajeihin. Itämeren K. veneficum -kantojen eitässä tutkimuksessa havaittu tuottavan karlotoksiineja. Itämerestä eristetyt C.brodyi-, K.veneficum- ja P.piscicida-kannat eivät eroa geneettisesti tai morfologisestimuilta merialueilta eristetyistä lajitovereistaan. Taustalla voi olla jatkuva geenivirta lajien eri populaatioidenvälillä. On myös mahdollista, että ribosomaalinen DNA on liian konservatiivinen alue kuvastamaan lajinsisäistävaihtelua. K. veneficum ja P. piscicida voivat tuottaa toksiineja ja muodostaa haitallisia leväesiintymiä. Vaikkatässä tutkimuksessa toksiinituotantoa ei havaittu, luonnonpopulaatiot voivat sisältää toksisuusfenotyypiltäänerilaisia kantoja, ja haitallisten leväesiintymien seurannan ja ennakoinnin kannalta tulisikin selvittää mahdollisestitoksiineja tuottavien kantojen esiintymistä Itämeressä. Suurin osa tutkimuksessa eristetyistä panssarisiimalevistä eimenestynyt laboratorio-olosuhteissa. Tutkimuksessa havaitut lajit eivät siis todennäköisesti edusta Itämerenpienikokoisten panssarisiimalevien koko monimuotoisuutta. Panssarisiimaleviin kohdistettu ympäristönäytteidensekvensointi eristyneessä ja vesimassoiltaan kerrostuneessa Itämeressä voisikin tuottaa lisätietoa niinpanssarisiimalevien monimuotoisuudesta yleensä kuin niiden erityispiirteistä Itämeressä.
  • Lehtosalo, Tuuli (2020)
    Lakes play a significant role in the carbon cycle, as they transport, modify, sequester and bury carbon. Climate has direct and indirect impacts on the carbon cycle of lakes. Small, shallow lakes in the northern boreal region are particularly sensitive to climate variability. By studying organic carbon accumulation and quality in lake sediments, and by comparing them to the Holocene climate reconstructions, we can deepen our understanding of the processes affecting carbon sedimentation, evaluate the current and future changes, and separate the on-going climate warming and other anthropogenic factors from natural ones. In this study, we examine carbon accumulation and quality during the Holocene in four lakes in one northern boreal catchment area. Sediment organic carbon content, accumulation rate, C/N-ratio, and d13C were measured and compared to each other as well as to the lake and drainage characteristics and temperature reconstructions. Temperature explained some of the variation in carbon accumulation and quality, in part the variability was attributed to the lake and drainage characteristics.
  • Seppälä, Markus (2020)
    Haitalliset vieraslajit ovat merkittävin uhka luonnon monimuotoisuudelle elinympäristöjen vähenemisen ja pirstoutumisen ohella. Vain pieni osa ihmisen alkuperäiseltä esiintymisalueeltaan uudelle alueelle tarkoituksella tai vahingossa siirtämistä vieraslajeista osoittautuu haitalliseksi, mutta ne saavat aikaan valtavaa vahinkoa alueen alkuperäisille lajeille ja luontotyypeille sekä ihmisille merkittävää taloudellista tai terveydellistä haittaa. Euroopan eliölajeista noin 5 % luokitellaan vieraslajeiksi, joista edelleen 10–15 prosenttia haitallisiksi vieraslajeiksi. Suomessa haitallisia vieraslajeja on luokiteltu noin 0,6 % eliölajeista. Uuden vieraslajin vakiintumiseen ja täyden levinneisyyden saavuttamiseen uudella alueella kestää keskimäärin 150 vuotta lajin saapumisesta. Leviämisvauhtia voi nopeuttaa vieraslajin sopeutuminen uuteen alueeseen, sopivien elinympäristöjen lisääntyminen sekä ilmaston lämpeneminen. Ilmaston lämpeneminen tulee myös helpottamaan uusien haitallisten vieraslajien saapumista Suomeen ja lisäämään niiden todennäköisyyttä selvitä hengissä ja levitä täällä. Jättipalsami (Impatiens glandulifera) on yksivuotinen, vain siemenistään leviävä kookas ruohovartinen kasvilaji, joka on Suomessa haitallinen vieraslaji. Kookas- ja nopeakasvuinen jättipalsami valloittaa tehokkaasti erityisesti kosteampia ja puolivarjoisia elinympäristöjä, ja leviää tehokkaasti virtaavan veden kuljettaessa siemeniä vesistössä eteenpäin. Jättipalsami voi syrjäyttää samalta kasvupaikalta valo- ja häirintäkilpailun avulla matalakasvuisempia ruohovartisia lajeja sekä houkutella sokeripitoisella medellä pölyttäjähyönteisiä muiden lajien luota. Jättipalsamikasvusto voi myös vähentää maanpäällisten ja maanalaisten selkärangattomien hyönteislajien ja -ryhmien monimuotoisuutta, sekä kasvien siemenpankin monimuotoisuutta. Tutkin pro gradu -työssäni kymmentä jättipalsamikasvustoa Itä- ja Pohjois-Helsingin alueella poikkeuksellisen kuumalla ja kuivalla kasvukaudella 2010. Seurasin kasvustoissa jättipalsamiyksilöiden kasvun fenologiaan eli ilmiasuun liittyviä muuttujia: korkeus, varren paksuus, lehtien lukumäärä, kukkien lukumäärä ja siemenkotien lukumäärä. Seurasin myös jättipalsamin ja muiden kasvustojen valtalajien peittävyyden kehitystä. Seurantajakson (18.5. –17.8.) jälkeen otin kasvustoilta näytteet maaperäanalyysiä varten ja keräsin kasvustoilta siemenkodat. Laskin siemenkotien sisältävien siementen määrät ja määritin kasvuston keskimääräisen siementuotantokapasiteetin 1 m2 alueella. Jättipalsamin fenotyyppinen plastisuus on korkea, eli se voi sopeutua hyvin elinympäristön muutoksiin, kuten valon saatavuuteen varjoisemmilla kasvupaikoilla. Varjossa kasvavat jättipalsamit tehostavat kasvuaan ja yhteyttävät tehokkaammin. Fenologiaseurannasta keräämäni mittausdatan alustavien tarkastelujen mukaan päätin tarkastella tilastollisesti kasvupaikan valoisuuden (kolme valoisuusluokkaa) vaikutusta jättipalsamin korkeuteen, mutta en löytänyt valoisuusluokkien välillä merkittävää eroa. Valoisammilla kasvupaikoilla kasvavat jättipalsamit kasvoivat keskimäärin paksummiksi, tuottivat enemmän lehtiä, kukkia ja siemenkotia sekä siemeniä. Kasvukauden 2010 olosuhteet vaikuttivat kasvustojen mittaustuloksiin ja siemenmääriin. Siementen määriin kasvustoissa vaikutti myös 8.8.2010 poikkeuksellisen rajun Sylvi-myrskyn rankkasadekuurot ja voimakkaat tuulenpuuskat.
  • Fontell-Seppelin, Laura (2020)
    According to The Finnish Act on Water Resource Management, the ecological status of Finnish streams and lakes have to be monitored and assessed based on the severity of human impact on biota. The ecological assessment of freshwaters is based on comparing the impacted ecosystems with those freshwater ecosystems of a nearly intact state. The Finnish Act on Water Resource Management is based on the European Union Water Framework Directive, or WFD. Macrophytes (aquatic bryophytes, macroalgae, and vascular plants) are used as an element in freshwater assessment. In Finland, the used of macrophytes have been long established along with other organism groups in ecological assessment of lakes, but macrophytes have not yet been used extensively in ecological assessment of rivers. A rough method has been developed, but further study and improvement needs to be made before reliable ecological assessments using river macrophytes can be done. Currently, there is a great need for a uniform method for river assessment using macrophytes. In Finland, the ecological state of freshwaters is classified by using biological metrics based on the abundance and variety of different organism groups. The biological metrics are converted to a scale of 0-1 into a so-called Ecological Quality Ratio (EQR) in order to be able to compare their results. Suitable biological metrics have been studied in Finland, and so far, the Percent Model Affinity (PMA) and Observed-to-Expected-taxa index (O/E-taxa index) have proven to be promising. Both metrics have been observed to explain human impact in the catchment and changes in water quality. These metrics are hence used in this thesis. The variety and abundance of freshwater macrophytes was studied according to the rough method developed at the Finnish Environment Institute (SYKE) in 2008. In this thesis, the objective was to study how the results of the biological metrics varied between different river parts of Mätäjoki. The EQR and biological metrics results obtained earlier from diatoms and benthic invertebrates were also compared with the results obtained with macrophytes in the same river parts. A possible link to the results of the River Habitat Survey (RHS) and riverbank vegetation was also studied. The biological metrics used in this thesis are based on using reference sites (sites in natural condition) to assess the ecological condition of the studied sites. Data collected for the MaaMet-survey by the Finnish Environment Institute formed the reference conditions. The reference sites included were as pristine as possible. The field method consisted of gathering macrophyte data from two 50-metre-long adjacent river parts: a riffle and a pool. A total of 18 rivers and pools were included, forming 9 river-pool pairs. The riverbank vegetation was studied on the banks of the pools. In this thesis, we observed significant variation in both the biological metrics results and EQR results. The results of the biological metrics were surprisingly low, indicating a possibly bad ecological condition. The mean of EQR results using combined data, bryophyte data and vascular plant data were found to be very similar. The EQR results using macrophyte data were considerably lower than the EQR results of the diatom and benthic invertebrate data. Macrophytes thus indicated a possibly inferior ecological state than diatoms and benthic invertebrates. The species richness of Mätäjoki was found to be considerably lower than that of the reference sites. The surprising results may indicate shortcomings in the rough river macrophyte method. The small size of the reference condition data and issues in the national Finnish river classification system may also be responsible for some of the results. Low EQR results, indicating low ecological state, may be a result from the impaired ecological state of Mätäjoki due to human impact. Moreover, the ecological assessment of urban rivers based on biota has in some studies produced unreliable results on other organism groups. The results show that biological metric values show a large variation between river parts. This must be taken into consideration in the development of the river macrophyte method and in choosing the sampling sites of studied rivers.
  • Koskenmäki, Auri (2008)
    Jokirapu (Astacus astacus) on Suomessa alkuperäislaji. Rapuruttoa hyvin sietävää täplärapua (Pacifastacus leniusculus) on istutettu lähinnä Etelä-Suomeen vuodesta 1967 lähtien. Täplärapu on kookkaampi, aggressiivisempi ja lisääntymiskykyisempi kuin jokirapumme. Yleensä täplärapu dominoi jokirapua, kun rapujen elinympäristöt kohtaavat. Täpläravun dominoivaa otetta voidaan selittää tiettyjen käyttäytymispiirteiden ollessa korreloituneena. Tietyt käyttäytymispiirteet voidaan liittää yleisesti tulokaslajien dominoivaan levittäytymiseen uusille alueille. Tulokaslajin täytyy levittäytyä epäröimättä, lisääntyä hyvin pienestä alkupopulaatiosta huolimatta sekä runsastuessaan aiheuttaa suuria vaikutuksia tunkeutumaansa yhteisöön. Tulokaslajiin käyttäytymisessä voisi siis olla korreloituneena aktiivisuus, rohkeus ja eksploratiivisuus. Käyttäytymissyndroomalla viitataan korreloituneisiin yksilön yhdenmukaisiin käyttäytymispiirteiden eroihin, jotka ilmenevät tietyssä tilanteessa ja/tai läpi tiettyjen kontekstien. Kontekstilla tarkoitetaan toiminnallista käyttäytymiseen liittyvää kategoriaa (esim. levittäytyminen). Populaatio tai laji voi ilmentää käyttäytymissyndroomaa. Jokaisella yksilöllä on oma käyttäytymistyyppinsä käyttäytymissyndrooman sisällä. Saman käyttäytymistyypin omaavien yksilöiden käyttäytyminen korreloi muiden yksilöiden käyttäytymisen kanssa järjestysluvullisen arvoasteikon mukaan. Käyttäytymissyndroomat voivat vähentää käyttäytymiseen liittyvää plastisuutta tai ylläpitää yksilöiden käyttäytymisen välistä vaihtelua. Pro gradu –työni tavoitteeni on tutkia joki- ja täplärapujen käyttäytymiseroja. Olen valinnut tutkimuksen kohteeksi aktiivisen, rohkean ja eksploratiivisen käyttäytymisen, joiden korrelaatioita on jo löydetty muutamilla lajeilla. Tutkin käyttäytymiserojen toistuvuutta sekä sukupuolen vaikutusta. Oletin löytäväni positiivisen korrelaation aktiivisessa, rohkeassa ja eksploratiivisessa käyttäytymisessä ravuilla (käyttäytymissyndrooma), ja oletin näiden käyttäytymispiirteiden välisten erojen olevan täpläravuilla suuremmat. Käyttäytymispiirrekokeet suoritin Viikissä kahteen kertaan käyttäytymisen toistuvuuden testaamiseksi. Käyttäytymisen toistuvuus osoittautui melko hyväksi, vaikka jälkimmäisen kokeen (=samaa käyttäytymistä mittaava koe tehty toiseen kertaan) tulokset olivatkin usein merkitsevästi erilaisia ensimmäisen kokeen tuloksiin verrattuna. Aktiivisuus toistui hyvin käyttäytymispiirrekokeiden kesken. Jokirapujen aktiivisena olo aika on suurempi kuin täpläravuilla aktiivisuuskokeessa ja eksploratiivisuuskokeessa. Täplärapujen aktiivisuus yleensä nousi jälkimmäisessä, kun taas jokirapujen aktiivisuus laski. Sukupuoleen sidottuja käyttäytymiseroja ei juurikaan löytynyt. Rohkeaa ja eksploratiivista käyttäytymistä ilmentävät kokeet osoittautuivat epäonnistuneiksi mittaamaan näitä käyttäytymispiirteitä. En voi saamieni tulosten perusteella todeta joki- tai täpläravuilla olevan käyttäytymissyndroomaa, jossa aktiivisuus, rohkeus ja eksploratiivisuus olisivat korreloituneena.