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Zebrafish optic nerve regeneration involves resident and retinal oligodendrocytes
No full textAbstract The visual system of teleost fish grows continuously, which is a useful model for studying regeneration of the central nervous system. Glial cells are key for this process, but their contribution is still not well defined. We followed oligodendrocytes in the visual system of adult zebrafish during regeneration of the optic nerve at 6, 24, and 72 hours post-lesion and at 7 and 14 days post-lesion via the sox10:tagRFP transgenic line and confocal microscopy. To understand the changes that these oligodendrocytes undergo during regeneration, we used Sox2 immunohistochemistry, a stem cell marker involved in oligodendrocyte differentiation. We also used the Click-iT TM Plus TUNEL assay to study cell death and a BrdU assay to determine cell proliferation. Before optic nerve crush, sox10:tagRFP oligodendrocytes are located in the retina, in the optic nerve head, and through all the entire optic nerve. Sox2-positive cells are present in the peripheral germinal zone, the mature retina, and the optic nerve. After optic nerve crush, sox10:tagRFP cells disappeared from the optic nerve crush zone, suggesting that they died, although they were not TUNEL positive. Concomitantly, the number of Sox2-positive cells increased around the crushed area, the optic nerve head, and the retina. Then, between 24 hours post-lesion and 14 days post-lesion, double sox10:tagRFP/Sox2-positive cells were detected in the retina, optic nerve head, and whole optic nerve, together with a proliferation response at 72 hours post-lesion. Our results confirm that a degenerating process may occur prior to regeneration. First, sox10:tagRFP oligodendrocytes that surround the degenerated axons stop wrapping them, change their “myelinating oligodendrocyte” morphology to a “nonmyelinating oligodendrocyte” morphology, and die. Then, residual oligodendrocyte progenitor cells in the optic nerve and retina proliferate and differentiate for the purpose of remyelination. As new axons arise from the surviving retinal ganglion cells, new sox10:tagRFP oligodendrocytes arise from residual oligodendrocyte progenitor cells to guide, nourish and myelinate them. Thus, oligodendrocytes play an active role in zebrafish axon regeneration and remyelination.Peer reviewe
Does in utero exposure to antiseizure medications affect the trajectory of cognitive development from 2 to 6 years of age?
No full textBackground: Antiseizure medications (ASM) are essential for patients with epilepsy. Though prenatal exposure to ASMs is associated with increased risk for malformations and neurocognitive problems, whether prenatal ASM exposure modifies offsprings' natural developmental trajectory has not yet been studied. Methods: This prospective study explores the effect of prenatal ASM exposure on the trajectory of cognitive development of children by studying the association of Bayley Scales III scores at 2 years with WISC-IV scores at 6 years of age and by comparing the results against those of unexposed children. Neurocognitive performance of 30 children with prenatal ASM exposure and 37 unexposed control children were evaluated. Correlations and separate ANCOVAs across these ages were compared between ASM exposed and unexposed controls. Results were controlled for maternal education, type of maternal epilepsy, child sex and child age at the assessment. Results: In unexposed participants, cognitive scores at the age of two years associated positively with working memory and processing speed at six years of age and receptive language scores at the age of two years associated with working memory at six years old. Conversely, with exposed children, there were no significant associations between two- and six-year test scores, and coefficients between receptive language and six-year-old working memory or processing speed differed significantly from unexposed children's coefficients. However, small sample size restricts the stability of the results, and the observed group differences in coefficients were not significant after removal of outlier. Conclusion: ASM exposure in utero may affect the trajectory of neurocognitive development, but the findings were impacted by an outlier and should be confirmed in larger cohort.Peer reviewe
Investigating the role of laminins in regulating the growth of breast cancer stem cells
No full textLaminins are essential components of the basement membrane that regulate epithelial architecture, cell polarity and stem cell behaviour. In breast cancer, alterations in laminin composition and spatial organisation are associated with disrupted tissue homeostasis, increased cellular plasticity and tumour progression. Despite their established role in the extracellular matrix, the contribution of specific laminin isoforms to breast cancer stem cell (CSC) dynamics remains poorly understood. This study aimed to investigate the role of laminins, particularly Lama1, in modulating CSC behaviour in luminal breast cancer cell lines.
CSC-enriched populations were isolated from T47D and MCF7 cell lines using〖CD44〗^high/〖CD24〗^low surface markers and evaluated for stemness via mammosphere formation efficiency (MFE) assays under serum-free and stem cell-supportive culture conditions. Functional assays revealed that CSC-enriched populations did not consistently exhibit enhanced mammosphere formation or spheroid growth, and in some cases showed reduced performance compared to non-CSC controls. RT-qPCR analysis demonstrated limited correlation between 〖CD44〗^high/〖CD24〗^low expression and stemness gene or laminin isoform transcription, suggesting that conventional CSC isolation using the surface markers CD44 and CD24 may not reliably identify functionally potent CSCs.
To further explore laminin involvement, cells were sorted based on surface Lama1 expression. High Lama1-expressing T47D cells displayed increased MFE and spheroid growth, particularly under low-serum conditions, indicating a context-dependent role for laminin in supporting CSC-like traits. However, this effect was limited to low-serum conditions in MCF7 cells and was not observed under stem cell-supportive conditions, highlighting a context-dependent response to laminin across cell lines. Additionally, embedding CSCs in laminin-111–functionalised hyaluronic acid-based hydrogels did not enhance growth and, in some cases, impaired spheroid formation. This suggests that exogenous laminin supplementation alone is insufficient to maintain CSC function in 3D culture.
These findings demonstrate that laminin-mediated regulation of CSCs is highly dependent on both intrinsic cellular properties and extrinsic environmental cues. The study highlights the limitations of surface marker-based CSC identification and reinforces the importance of integrating molecular, phenotypic and functional assays when evaluating CSC populations. Laminin expression emerges as a potential modulator of CSC behaviour in luminal breast cancer, however, further investigation is needed
Trends in Cancer Incidence and Mortality by Educational Groups in Finland : A Population-based Study of Breast, Lung, Colorectal, and Prostate Cancers
No full textThis thesis examines educational differences in cancer incidence and mortality in Finland. The study focuses on lung, colorectal, prostate, and breast cancers, as well as on overall cancer incidence and mortality during the period 1976-2023. The purpose of this study is to evaluate the differences in cancer incidence and mortality across educational groups, and to examine whether these differences have changed over time.
The analyses were based on data from the Finnish Cancer Registry and Statistics Finland, covering incident cancer cases and deaths from cancer in the population of Finland from 1976 to 2023. Age-standardised cancer incidence and mortality rates were calculated for each cancer site and educational group by sex and calendar period. Poisson regression models were applied to estimate age-adjusted rate ratios (hazard ratios) between educational groups. In addition, temporal changes in cancer rates and rate ratios across educational groups were examined.
This study analysed incidence and mortality differences between three educational levels for breast, colorectal, lung, and prostate cancers in Finland from 1976 to 2023. Overall, an increase was observed in cancer incidence while cancer mortality showed a decreasing trend, but the size and direction of educational differences varied by cancer type. Men with basic education had the highest incidence rates. Among women, cancer incidence rose among all educational groups, but the highest rates were consistently at high educational level, most likely reflecting high breast cancer incidence among highly educated. Mortality declined in all groups, but the largest reductions were observed among the highly educated, leading to persistent or widening inequalities.
The results indicate that person’s education level still remains a significant determinant of health, including cancer incidence and mortality, in Finland. The differences in cancer incidence and mortality highlight the need for targeted prevention and screening strategies, as well as improving health literacy and awareness on cancer risk factors, particularly among groups with lower levels of education. Future studies should examine the mechanisms underlying these differences in more detail and evaluate the effectiveness of measures aimed at reducing inequalities in cancer burden
Spatial information in targeting climate measures for cultivated peat soils
No full textClimate change, driven by human-induced greenhouse gas emissions, is already
causing severe weather events and threatening global food and water security.
Organic soils, especially peatlands, are major carbon stores, but their drainage
for agriculture releases large amounts of CO₂ and N₂O. In drained peatlands,
microbial decomposition of organic matter accelerates due to oxygen exposure,
increasing greenhouse gas emissions. Re-wetting these soils restores anoxic
conditions, reduces CO₂ and N₂O emissions, and enables peat formation, although
it may increase CH₄ emissions. Nevertheless, total emissions from rewetted
peatlands are significantly lower than from drained ones, making rewetting
the most effective mitigation strategy. Agriculture plays a significant role
in GHG emissions both in the EU and Finland, particularly through emissions
from cultivated organic soils. In Finland, emissions from cultivated peat soils
alone exceed those of the entire agriculture sector, highlighting their disproportionate climate impact despite covering a small share of farmland. While emissions from other sectors have declined, agricultural emissions especially from
organic soils have remained stable or increased, underscoring the need for targeted mitigation in this sector.
Geographic Information Systems (GIS) enable the integration and analysis of
spatial data to identify priority areas for environmental measures, such as peatland
restoration or sustainable land use. When developed into Decision Support
Systems (DSS), GIS tools allow policymakers to target interventions more effectively by aligning actions with areas of highest environmental benefit and costefficiency. This spatially informed approach enhances the precision, transparency, and impact of policy decisions, making it a valuable asset for evidence based environmental governance especially when supported by high-quality national
datasets.
This dissertation aims to evaluate whether the current use of cultivated peatlands
in Finland aligns with national climate targets and to assess the potential for
rewetting these areas as a mitigation strategy using GIS based analyses. By exploring spatial targeting tools and geospatial data, the study supports more effective and precise policy actions for reducing greenhouse gas emissions from
peat soils.
Results show that Finland has a large technical potential for rewetting cultivated peat soils, far exceeding current national targets, but realizing this potential requires stronger policy action. Expanding rewetting efforts to include intensively cultivated areas is essential, as targets set in Restoration regulation will cover only a small portion of emissions. GIS-based tools, such as the depth-to-water index, offer promising methods for identifying suitable rewetting sites and improving the precision of climate measures. To maximize impact, investments in
high-quality data, clear policy definitions, and user-friendly decision-support
tools are crucial for guiding land use changes and achieving long-term emission
reductions.Ilmastonmuutos aiheuttaa vakavia sääilmiöitä ja uhkaa maailman ruokaturvaa.
Erityisesti eloperäiset maalajit, kuten turvemaat, ovat merkittäviä hiilivarastoja,
mutta niiden ojitus saa aikaan merkittävän määrän kasvihuonekaasupäästöjä.
Ojitetuilla turvemailla hapelliset olosuhteet käynnistävät hajotusprosessin, jossa
turpeeseen kertynyt orgaaninen aines pääsee mikrobitoiminnan kiihtyessä hajoamaan. Prosessin seurauksena syntyy päästöjä kaasumaisina yhdisteinä ilmaan ja ravinnekuormituksena vesistöön. Maataloudessa viljellyt turvepellot ovat tunnetusti merkittävä kasvihuonekaasupäästöjen lähde sekä EU:ssa että Suomessa. Suomessa pelkästään viljellyt turvemaat aiheuttavat enemmän päästöjä kuin koko muu maataloussektori yhteensä, vaikka ne kattavat vain pienen osan viljelyalasta. Muiden sektoreiden päästöjen laskiessa maatalouden erityisesti turvemailta muodostuvat päästöt ovat pysyneet ennallaan tai kasvaneet, mikä korostaa tarvetta turvepelloille kohdennettaville päästövähennystoimille. Vettämisen avulla voidaan turvepelloille palauttaa hapettomat olosuhteet, ja siten vähentää päästöjä ja mahdollistaa turpeen muodostuminen uudelleen.
Paikkatietojärjestelmät (GIS) mahdollistavat ympäristötoimien, kuten turvemaiden
ennallistamisen ja kestävän maankäytön, kohdentamisen. Paikkatietomenetelmistä
voidaan kehittää päätöstukijärjestelmiä (Decision Support Systems;
DSS). Päätöksentekoa tukevien menetelmien tavoitteena on lisätä tutkittuun tietoon perustuen resurssitehokkuutta. Tätä voi toteuttaa esimerkiksi kohdentamalla toimenpiteitä alueille, joilla saavutetaan suurimmat ympäristöhyödyt. Se myös tehostaa julkisin varoin kohdennettavien toimenpiteiden kustannustehokkuutta. Paikkatietoon perustuvat lähestymistavat parantavat politiikkatoimien tarkkuutta ja vaikuttavuutta, etenkin kun käytettävissä on laadukasta aineistoa.
Tämän väitöskirjan tavoitteena oli arvioida paikkatietoa hyödyntäen, vastaako
viljeltyjen turvemaiden nykyinen käyttö Suomen asettamia maatalouden ilmastotavoitteita, sekä selvittää paikkatietoon perustuvien analyysien avulla turvepeltojen vettämismahdollisuuksia päästövähennyskeinona Suomessa. Tutkimuksen käytännöllisenä tavoitteena on paikkatietopohjaisia kohdentamismenetelmiä hyödyntämällä tukea tehokkaampaa ja tarkempaa ilmastopolitiikkaa.
Tulokset osoittavat, että Suomessa on viljeltyjen turvemaiden vettämiseen huomattavatekninen potentiaali, joka jopa ylittää nykyiset kansalliset tavoitteet. Tämän potentiaalin hyödyntäminen edellyttää kuitenkin nykyistä vaikuttavampia
poliittisia ohjauskeinoja. Tulosten valossa myös aktiivisessa käytössä olevia peltoja
on välttämätöntä vettää, ja esimerkiksi ennallistamisasetukseen kirjatuilla vettämistavoitteilla saadaan katettua vain pieni osa päästövähennyksistä, joita
asetettuihin tavoitteisiin pääsemiseksi tarvittaisiin. GIS-pohjaiset työkalut, esimerkiksi depth-to-water-indeksi, ovat lupaavia työkaluja vettämiseen sopivien
alueiden tunnistamiseen, mutta tarkkuuden parantamiseksi tarvitaan laadukkaampaa tausta-aineistoa. Päästöjen vähentämiseksi ja hyötyjen maksimoimiseksi tarvitaan selkeitä poliittisia päätöksiä sekä päätöksentekoa tukevia ja ohjaavia menetelmiä
Role of riboflavin and nicotinamide in vitamin B12 production by Propionibacterium freudenreichii
No full textRiboflavin (RF) serves as a precursor for the biosynthesis of 5,6-dimethylbenzimidazole (DMBI), the lower ligand of vitamin B12, in Propionibacterium freudenreichii. Nicotinamide (NAM) has been reported to enhance this biosynthetic pathway. In this study, we investigated the effect of RF and NAM supplementation on vitamin B12 production by P. freudenreichii DSM 20271 in barley malt extract-based model medium. A medium containing 10 % (w/v) concentrated malt extract supplemented with lactate and tryptone supported superior growth and B12 production. RF (1, 3 and 40 mu M with 27 mM NAM), and NAM (0.1, 0.6 and 27 mM with 3 mu M RF) were evaluated for their impact, with 100 mu M DMBI used as a reference. RF concentrations >= 3 mu M significantly enhanced B12 production, while NAM was effective only at 27 mM. Growth and metabolite profiles were largely unaffected, suggesting that increased B12 synthesis resulted from improved precursor availability rather than enhanced biomass. Transcriptomic analysis revealed significant downregulation of RF biosynthesis genes, consistent with feedback inhibition from exogenous RF, while B12 biosynthesis genes remained transcriptionally stable, indicating that the observed increase in B12 production is primarily regulated at the metabolic rather transcriptional level. These findings demonstrate that B12 production in P. freudenreichii can be enhanced using RF and NAM precursors, but practical applications must balance efficacy with NAM safety limits for use in B12-enriched fermented foods.Peer reviewe
Ruoansulatushormonin reseptoriagonistit: Niiden reseptorien ilmentyminen ja toiminnalliset vaikutukset adiposyyteissä ja rasvakudoksen endoteelisoluissa
No full textObesity and other metabolic diseases are associated with adipocyte dysfunction, including insulin resistance of adipocytes and inflammation. These adverse changes impair insulin signalling in adipocytes and compromise nutrient metabolism both in adipose tissue and whole-body levels. GLP-1 and/or GIP receptor agonist drugs have been developed to treat type 2 diabetes and obesity. These drugs mimic the actions of incretin hormones, which enhance insulin secretion from the pancreas in response to food intake and play a crucial role in maintaining normal blood glucose levels. Additionally, the drugs suppress appetite, supporting weight loss. Beyond these central effects, the drugs also exert direct beneficial effects on adipocytes. This study investigated the expression of GLP-1 and GIP receptors in different cell types of adipose tissue, the cellular responses induced by the agonist drugs, and their impact on insulin signalling in SGBS preadipocytes. Expression of GLP-1 and GIP receptors was observed in SGBS adipocytes and endothelial cells at both mRNA and protein levels, with GIP receptor showing higher expression. The agonist drugs did not consistently activate the ERK1/2 pathway in the preadipocytes. However, semaglutide and tirzepatide enhanced insulin-stimulated Akt activation, indicating a functional response in the preadipocytes. This finding suggests that the drugs have a direct effect on SGBS preadipocytes. If a similar insulin-sensitizing effect is observed in mature adipocytes, this could represent a direct and beneficial mechanism to alleviate adipocyte dysfunction in obesity. Further studies using mature adipocytes and adipose tissue endothelial cells are needed to confirm these effects and their functional relevance in adipose tissue metabolism.Adiposyyttien insuliiniresistenssi ja rasvakudoksen tulehdustila ovat osa lihavuuteen ja muihin aineenvaihdunnan häiriöihin liittyvää adiposyyttien toimintahäiriötä. Nämä haitalliset muutokset häiritsevät adiposyyttien insuliinisignalointia, mikä heikentää ravintoaineenvaihduntaa sekä rasvakudoksessa että koko elimistössä. GLP-1- ja/tai GIP-reseptoriagonistit on kehitetty tyypin 2 diabeteksen ja lihavuuden hoitoon. Ne jäljittelevät inkretiinihormoneja, jotka ovat keskeisiä normaalin verensokerin ylläpidossa, sillä ne tehostavat haiman insuliinineritystä syömisen jälkeen. Agonistit myös vähentävät ruokahalua, mikä tukee lihavuuden hoitoa. Lisäksi niillä on suoria, suotuisia vaikutuksia adiposyytteihin. Tässä tutkimuksessa selvitettiin GLP-1- ja GIP-reseptoreiden ilmentymistä rasvakudoksen eri solutyypeissä sekä agonistien vaikutusta ERK1/2-signaalinsiirtoreittiin ja insuliinisignalointiin SGBS-preadiposyyteissä. Tulosten perusteella GLP-1- ja GIP-reseptoreiden lähetti-RNA:ta ja proteiinia ilmentyy muun muassa SGBS-adiposyyteissä ja erilaisissa endoteelisoluissa, joskin GIP-reseptorin ilmentyminen oli voimakkaampaa. Reseptoriagonistit eivät johdonmukaisesti aktivoineet ERK1/2-signaalinsiirtoreittiä preadiposyyteissä, mutta semaglutidi ja tirzepatidi tehostivat Akt:n aktivaatiota yhdessä insuliinin kanssa. Tämä viittaa siihen, että agonistilääkkeillä saattaa olla toiminnallisia vaikutuksia preadiposyyteissä sekä siihen, että lääkkeillä on suoria vaikutuksia näihin soluihin. Lääkkeiden kyky lisätä insuliiniherkkyyttä voi olla mahdollinen suora mekanismi, jolla adiposyyttien toimintahäiriötä voidaan parantaa lihavuudessa. Jatkotutkimuksia kypsillä adiposyyteillä ja rasvakudoksen endoteelisoluilla tarvitaan, jotta lääkkeiden vaikutukset näiden solujen signalointiin ja niiden toiminnallinen merkitys rasvakudoksen aineenvaihdunnassa voidaan vahvistaa
Measurement Invariance in Learning Anxiety Questionnaires: Comparing Confirmatory Factor Analysis and Exploratory Structural Equation Modeling
No full textThe purpose of this study was to compare measurement invariance results between Multi-
Group Factor Analysis (MG-CFA) and Exploratory Structural Equation Modelling (ESEM).
The data consisted of student responses to the Math Anxiety Questionnaire (MAQ) and the
Reading and Writing Anxiety Questionnaire (RWAQ), collected in Finnish schools between 2022
and 2024. This thesis was part of the tool development project at the Turku Research Institute
for Learning Analytics (TRILA) at the University of Turku. The aim was to test whether the
structure of the questionnaires was psychometrically valid to ensure that the schools using these
questionnaires would be offered reliable information about their students’ emotional reactions
towards learning.
Both math and reading anxieties have been proven to be distinct from performance levels in
psychological literature, as well as from general or other types of anxiety, and therefore, they
need to be measured with their own measuring instruments. Since these constructs are not easy
to measure, they are usually measured with latent variables called factors. Confirmatory factor
analysis (CFA) is the most commonly used method to examine factor structure when there is a
prespecified factor structure. In this thesis, the results from CFA were compared to the results
obtained from ESEM, which is an exploratory method allowing flexible cross-loadings. After
validating the factor structure, measurement invariance is usually tested. If measurement invari-
ance holds, it means that the questionnaire measures the same constructs equivalently across
different subpopulations, for example, sexes or different age groups. Measurement invariance is
tested with MG-CFA by comparing nested models, where different constraints are set on the
model parameters. The different levels of invariance used in this thesis were configural, metric,
and scalar invariance.
In the theory section of this thesis, CFA, MG-CFA, and ESEM are explained, as well as the
concept of measurement invariance. Different methods of assessing model fit are also discussed.
In the empirical section, the factor structure and measurement invariance of the questionnaires
were examined. Both questionnaires demonstrated good model fit based on both CFA and
ESEM. For the RWAQ, measurement invariance was supported at all levels tested, in terms of
gender, grade, school language, and year of measurement, from which longitudinal invariance
was tested. For the MAQ, measurement invariance was supported across all grouping variables
except grade, where partial scalar invariance was achieved. This study shows that, compared to
CFA, ESEM offers a more flexible framework that allows for cross-loadings, resulting in a better
model fit and more robust invariance testing, although caution is required to avoid overfitting
Exploring Changes in Lymph Node Microenvironment in Patients with Myasthenia Gravis Using Tissue Cyclic Immunofluorescence
No full textMyasthenia gravis (MG) is a chronic autoimmune neurological disease characterised by fluctuating muscle weakness. Pathogenic autoantibodies against proteins of synaptic membrane of the neuromuscular junction disrupt synaptic signalling and impair neuromuscular transmission. It is a highly heterogenous disease, categorized into several subtypes based on clinical presentation, serological status, age at onset and associated thymic pathology. Although rare, a steady increase has been observed globally in the incidence and prevalence of MG cases over the past two decades which is more prominent in the elderly population. Contrary to early onset myasthenia gravis (EOMG), the role of thymus in late-onset myasthenia gravis (LOMG) pathogenesis is not fully established due to age related thymic atrophy and limited benefit of thymectomy in this age group. Additionally, the source of acetylcholine receptor (AChR) antibodies in LOMG is unknown and there is a suggestion that these antibodies might arise from outside the thymus in these cases.
Lymphocytes derived from lymph nodes (LN) of MG patients have been shown to spontaneously produce AChR antibodies in vitro however detailed studies looking at changes in cellular environment of LN from MG patients have not been done. We utilized multiplex fluorescent immunohistochemistry technique to study the LN microenvironment and cellular changes in archival LNs from MG patients and compared them to controls. However, we did not find any significant differences between LNs from MG patients and controls in the abundance of different cell subtypes. Majority of our MG samples had been collected before disease onset/diagnosis and more research is needed with bigger sample size and samples collected after disease onset to fully comprehend the effect of the disease on LNs
Saastelähdejäljityksen käyttö uimavesien laadun valvonnan tukena
No full textUimaveden mikrobiologista laatua yleisillä uimarannoilla valvotaan Suomessa seuraamalla
indikaattorimikrobien lukumääriä vesinäytteissä. Indikaattorimikrobeina käytetyt Escherichia
coli sekä suolistoperäiset enterokokit ovat peräisin ihmisten ja eläinten ulosteesta, ja niiden
avulla pyritään arvioimaan ulosteperäisen saastumisen määrää uimavedessä. Ulosteperäinen
materiaali sisältää useita erilaisia taudinaiheuttajia, minkä vuoksi sille altistuminen saattaa
aiheuttaa terveysriskin uimarannan käyttäjille.
Indikaattorimikrobien lukumäärien määrittäminen on helppo, kustannustehokas ja
kohtuullisen luotettava menetelmä, mutta näiden mikrobien lukumäärän perusteella ei pystytä
päättelemään, mistä ulosteperäinen saastuminen on peräisin. Saastelähteen tunteminen on
uimarantavesien laadun valvonnan kannalta tärkeää, sillä poikkeamiin veden laadussa ei
pystytä reagoimaan tehokkaasti, mikäli saastumisen syy ei ole selvillä. Kaikki ulosteperäinen
saastuminen ei myöskään aiheuta samanlaista terveysriskiä uimarannan käyttäjille, sillä
ihmisistä peräisin oleva ulosteperäinen materiaali sisältää yleensä enemmän ihmiselle tautia
aiheuttavia mikrobeja kuin eläimistä peräisin oleva uloste. Uudet
saastelähdejäljitysmenetelmät, kuten isäntäspesifien mikrobien tunnistaminen PCR-
menetelmillä ja kemiallisten yhdisteiden tutkiminen, mahdollistavat saastelähteiden aiempaa
tarkemman tunnistamisen ja tehostavat uimavesien laadun ylläpitoa ja valvontaa.
Tämän lisensiaatintutkielman tavoitteena oli luoda katsaus käytössä oleviin uimaveden laadun
tutkimusmenetelmiin, valvonnan käytäntöihin sekä saastelähdejäljitysmenetelmien
käyttökelpoisuuteen saastelähteen tunnistamisessa. Tutkielmaan sisältyvän
alkuperäistutkimuksen tavoitteena oli selvittää ulosteperäisen saastumisen esiintymistä eräällä
rannikolla sijaitsevalla uimarannalla kesällä 2024 ja erotella mahdollisia saastelähteitä
kyseisellä alueella.
Uimarannalta ja sen lähialueilta kerättiin kesäkauden 2024 aikana 115 vesinäytettä 11 eri
näytepisteestä. Vesinäytteistä tutkittiin E. coli -bakteerin ja suolistoperäisten enterokokkien
lukumääriä, ulosteperäisen saastumisen geenimarkkereita DNA- sekä RNA-pohjaisilla
menetelmillä, lämpökestoisten kampylobakteerien esiintymistä sekä kofeiini- ja
ibuprofeenipitoisuuksia. Indikaattoribakteereita löytyi lähes kaikista tutkituista näytteistä.
Varsinaiselta uimaranta-alueelta kerätyistä näytteistä 7,0 % ylitti E. coli -bakteerille ja 11 %
suolistoperäisille enterokokeille asetetun toimenpiderajan rannikon yleisten uimarantojen
uimavedessä.
Mikrobiologisessa saastelähdejäljityksessä tutkittiin 34:stä vesinäytteestä yleistä
ulosteperäistä saastumista kuvaava GenBac3-markkeri, ihmisperäinen HF183-markkeri,
lintuperäinen GFD-markkeri sekä koirista peräisin oleva DogND5-markkeri. GenBac3-
markkeria havaittiin kaikissa tutkituissa vesinäytteissä. Seuraavaksi yleisimmin näytteistä
havaittiin GFD-markkeria (32 % näytteistä DNA-pohjaisessa määrityksessä ja 79 % näytteistä
RNA-pohjaisessa määrityksessä). DogND5-markkeria havaittiin 15 % näytteistä ja HF183-
markkeria DNA-määrityksessä 5,9 % näytteistä ja RNA-määrityksessä 21 % näytteistä.
Indikaattorimikrobituloksia sekä saastelähdejäljityksen tuloksia verrattiin myös alueen
säätietoihin, ja veden laadun ja edeltäneiden vuorokausien sadekertymän, lämpötilan ja tuulen
voimakkuuden välillä havaittiinkin olevan korrelaatioita. Tämän tutkielman perusteella
tutkimuksen kohteena olleen uimarannan vesialueilla esiintyi ulosteperäistä saastumista
kesällä 2024, ja veden laatu oli heikompi erityisesti rankkasateiden jälkeen sekä viileällä
säällä