Maatalous- metsätieteellinen tiedekunta

 

Recent Submissions

  • Zinchenko, Ganna (Helsingin yliopisto, 2016)
    The characterization of flower-specific ubiquitin-proteasome system (UPS) components and identification of their functional molecular networks will help to elucidate the involvement of UPS in regulating flower development and/or flowering time and, therefore, reproductive success of the plant. UPS component COP1 ubiquitin E3 ligase is known to regulate flowering time. The earlier data suggests that COP1 could be involved in regulating cytokinin signaling possibly through Arabidopsis Response Regulator1 (ARR1) ubiquitination. ARR1 is a B-type cytokinin response regulator, and it has recently been shown to be an unstable protein. Furthermore, KMD, F-box protein in SCF E3 ligase complex, has been shown to interact with ARR1 as well. The aim of this study is the characterization of COP1 interaction with novel target proteins ARR1, ARR2, ARR10 and ARR12 that appear to be regulated in different ways. Moreover, KMD proteins were included within the study as a possible competitor of COP1 for interaction with ARR1. In order to perform interactome studies, yeast two-hybrid assay with a preceding molecular cloning of the genes of interest was used. The results can be used to unravel the role of ubiquitin mediated regulation of cytokinin pathway.
  • Ververis, Ermolaos (Helsingin yliopisto, 2016)
    Cobalamin (vitamin B12) occurs naturally in some animal-derived foods and is produced exclusively by microorganisms. An optimised protocol was used for extraction of cobalamin from cheese matrixes. No pseudocobalamin was detected in any of the examined samples. Cobalamin levels (mg/100g FW) detected in commercial emmental cheeses of three ripening stages did not alter significantly (P>0.05). Similar results were observed during the ripening of experimental semi-hard cheeses with or without propionibacteria. Existence of propionibacteria as adjunct culture in experimental cheeses did not alter significantly contribution on cobalamin levels of the cheese (P>0.05). The findings indicate that in the studied cheese matrixes the presence of propionibacteria did not affect the amount of cobalamin. The conditions to which propionibacteria are subjected during cheese manufacture and ripening and the presence of adenosyl-cobalamin in milk may be factors that repress cobalamin synthesis in Swiss- type cheeses. To date, the only known food grade microorganism that can produce cobalamin is Propionibacterium freudenreichii. This microorganism can also produce small amounts of pseudocobalamin, a compound structurally similar to cobalamin. BluB/CobT2 fusion gene is the factor that differentiates the two compounds upon their biosynthesis, by synthesizing and binding 5,6-dimethylbenzimidazole (DMBI) to the final molecule of cobalamin. In the present study, attempts to inactivate this gene were performed in order to investigate the existence of an alternative enzyme, capable of activating adenine for attachment as a lower ligand in pseudocobalamin, instead of DMBI. An electroporation protocol was implemented in order to transform plasmids containing bluB or cobT2 fragments and gene encoding erythromycin resistance in propionibacteria. Following transformation plasmid carrying bacteria were selected by cultivation in medium containing erythromycin. Homologous recombination of the bacterial genome and the non-replicative plasmid was expected to occur, leading to insertional mutagenesis. Colonies appeared after 7 and 11 days and were identified as propionibacteria but the disruption of bluB/cobT2 gene could not be verified. Inefficient transformation protocol, satellite colonies, low transformation efficiency, or choice essentiality of the bluB/cobT2 are among the possible explanations for the outcome of the experiment. Electroporation conditions should be optimized towards a more efficient P. freudenreichii transformation.
  • Juusela, Maija (Helsingin yliopisto, 2016)
    Sodium chloride is considered to be one of the most important ingredients in sausage production in terms of safety and quality. It is the biggest source of sodium in sausages which has been proven to have negative effects on health. In Finland meat dishes and products are responsible for one third of the sodium consumption per day for men and one fourth for women. Finland is going to begin applying the EU regulation on the provision of food information to consumers by the end of the year 2016. This regulation concerns nutrient information in the food packages. According to the regulation the new threshold value for sausages containing less salt than usual is 1,5 %. The objective of this study was to develop a sausage within the new threshold containing less than 1,2 % added salt and examine changes in sensory properties caused by salt replacements. The sensory method used in this research was quantitative comparison of multiple samples. The variable in the pork meat sausage samples was different potassium chloride salt replacers. Changes in sensory properties were examined by comparing the taste and texture of the samples to a reference sample. The taste properties assessed were saltiness, bitterness and metallic taste. Textural properties under evaluation were firmness and juiciness. The texture was also studied by firmness tests with Instron texture analyzer. According to the statistical results with applied Bonferroni correction, the only significantly differing property was saltiness. Two of the three replacer samples were assessed as less salty than the reference. However, compared to the hidden reference samples, no significant differences were detected. According to the results from the texture analysis, the sample containing the highest potassium chloride content was the least firm. On the basis of the sensory analyses, potassium chloride could be a considerable alternative to sodium chloride as a salt replacer.
  • Jääskeläinen, Susanna (Helsingin yliopisto, 2016)
    The cold storage, utilized to increase the shelf life of raw milk, favors the growth of psychrotrophic bacteria. Psychrotrophs are considered as problematic because they produce heat-stable spoilage enzymes. In addition, some pathogenic bacteria are capable of growing at cold storage temperatures and it has been observed in previous studies that the psychrotrophs in raw milk can be resistant to several antibiotics. In the literature review section of this study, the microbial composition of raw milk and the effect of cold storage, nitrogen gas (N2) treatment and activation of the lactoperoxidase system (LPS) on the raw milk bacteria was reviewed; moreover, the evolution, spread and mechanisms of bacterial antibiotic resistance and the antibiotic resistance on dairy farms and of raw milk bacteria was reviewed. Also the methods to study raw milk bacteria and their antibiotic resistance were documented. The aim of the experimental part was to study the effects of cold storage, N2 gas treatment and LPS treatment on the levels of antibiotic resistant bacteria in raw milk. Untreated, N2-treated and LPS-treated raw milk samples were stored at 6 °C and the counts of bacteria resistant to gentamicin, ceftatzidime, levofloxacin and trimethoprim-sulfamethoxazole were determined in the beginning of the experiments and after three and seven days of cold storage. The antibiotic resistance and spoilage features of bacterial isolates selected from different plates were compared. In addition, DNA fingerprints of selected isolates were obtained by rep-PCR method and for a couple of isolates 16S rRNA gene partial sequencing was performed. The presence of certain antibiotic resistance genes for the isolates partially identified was investigated using a PCR-based method. The length of cold storage affected the proportions of antibiotic resistant bacteria in raw milk. The proportions of antibiotic resistant bacteria in the control milk sample were generally, with the exception of TS-resistant bacteria in some cases, at their lowest after seven days of cold storage when the milk was, though, microbiologically unacceptable. There was a lot of variation in the prevalence of bacterial antibiotic resistance between the milk samples treated differently. The proportions of resistant bacteria were on average clearly higher in LPS samples than in control samples, whereas the effect of the N2 treatment on the proportions of resistant bacteria varied between the experiments. The bacterial isolates resistant to all the considered antibiotics produced less frequently protease and phospholipase than the isolates resistant to fewer antibiotics. The isolates from LPS samples were more frequently resistant to all the antibiotics studied and produced less frequently protease and phospholipase than the isolates from control and N2-treated samples. On the basis of the rep-PCR fingerprints, there were both similar and different strains among the bacterial isolates. Based on the 16S rRNA partial gene sequence, two isolates were identified as Pseudomonas spp. and two isolates as Stenotrophomonas spp. The targeted antibiotic resistance genes were not detected among the considered isolates. Possible reasons can be variations in the gene sequences, suboptimal PCR conditions or that the isolates lacked the genes studied. A PCR product was obtained for one Pseudomonas isolate using mexA-F/R primers, but according to the database the gene sequence did not show homology with antibiotic resistance genes. Further analyses would be required to confirm if the gene studied is linked to antibiotic resistance.
  • Kohtala, Elisa (Helsingin yliopisto, 2016)
    The literature review of this thesis focused on properties of pork meat, meat colour formation and the effect of modified atmosphere packaging (MAP) on microbiology and sensory characteristics of meat. The aim of the experimental work was to study the effects of MAP on microbiological and sensory quality of pork meat and to develop the most optimal modified atmosphere for consumer packages for pork loin (longissimus dorsi) roasts. The samples were stored in cold room at 5 ºC for 12 days after packaging (and for 15 days for microbiological analysis). The properties measured were: drip loss, pH, colour, cooking loss, tenderness and protein oxidation by measuring free thiol groups. In addition, microbiological analysis, sensory evaluation and consumer survey were carried out. Experimental part consisted of three different trials. In each trial, also the present packaging gas (f) used for the product was studied as a reference. After trials 1 and 2, it was concluded that packaging gas (b) was as the most optimal modified atmosphere for the product. At trial 3, packages (a), (b), (f) and (g) were studied. Samples in package (g) were more tender than samples in package (f) both in the instrumental measurements (p<0,001) and in sensory evaluation (p<0,05). Package (f) had more protein oxidation than other packages (p<0,01). Microbiological quality was good both in packages (b) and (f) and poorest in package (a) after 15 days of storage. Nevertheless, packaging (f) was rated significantly (p<0,001) higher in the consumer survey than package (b). It could be concluded that the present packaging gas (f) would still be the most optimal one for pork loin roasts, as the appearance of the meat is one of the most critical factors affecting consumers’ purchasing decision.
  • Räisänen, Heidi (Helsingin yliopisto, 2016)
    Sustainable development and fluctuating petroleum prices encourage manufacturing packaging materials in a more natural and cost-effective way. Green economy utilizes renewable raw materials from the nature which can be used in larger scale applications such as packaging industry. Barrier properties can be enhanced by manufacturing multilayer structures with a coating made of organic materials such as cellulose nanofibrils (CNF). With CNF it is possible to provide barrier and mechanical improvement to packaging material at low added cost. Together with hydrophobic films (e.g., HDPE, LDPE) also the low water vapor permeability and heat sealing properties can be enhanced. The aim of this thesis was to utilize CNF as a barrier layer for bio-based flexible food packaging pouches. A study consisted of examining 1-layer bio-HDPE film, 2-layer bio-HDPE/CNF film and 3-layer HDPE/CNF/LDPE film and testing their permeability (for oxygen, water vapor and aroma), sealability, tensile strength, influence of irradiation and aroma compounds (clove), and suitability for modified atmosphere packaging, MAP (with hazelnuts). The 2- and 3-layer multilayer films provided very good oxygen barrier under dry conditions, although aroma exposure increased the oxygen permeability rates. Pouches made of the 2-layer film were the most feasible for MAP, even though the 3-layer film would also have been an alternative if the film quality had been optimal. The oxidation of fatty acids in hazelnuts could be slowed down by using multilayer structure including CNF barrier under modified atmospheric conditions. This study helps to verify the feasibility of the bio-based multilayer films as a new food packaging material, and demonstrates the use of CNF as a high-barrier layer in a laminate. Bio-HDPE/CNF/bio-LDPE multilayer has potential for utilizing it in flexible food packaging pouches if the manufacture process is standardized leading into homogeneous film quality.
  • Liu, Mengxia (Helsingin yliopisto, 2016)
    Conifers are used for forest plantations and as landscape trees. Norway spruce is the main softwood species in Finland and can occasionally be observed in urban areas. However, root rots of conifer trees caused by Heterobasidion annosum leads to huge economic losses not only in Finland but also in other European countries. Due to the availability of complete genome sequence for both host and pathogen, in this study using Norway spruce and its root rot pathogen (Heterobasidion annosum) as an experimental model, the host-pathogen interaction was investigated. Conifer trees have established a variety of defense mechanisms to repel microbial infections, including constitutive barriers, accumulation of antimicrobial chemicals, activation of signaling pathways and induction of defense-related compounds resulted from an intra-organismic response including cell death. In the conifer pathosystem, cell death associated necrotic browning reactions promote tissue colonization by necrotrophic pathogens such as Heterobasidion annosum. By contrast, in crop plants, cell death associated hypersensitive response (HR) is known to inhibit invasive growth of biotrophic pathogens. However, not much is known about the chemical and molecular characteristics of necrotic cell death responses observed in different developmental stages of conifers from seedlings to mature trees. In addition, the term reaction zone is often used to describe responses of tree tissues bordering the heartwood to pathogenic infections, but nothing is known on whether there are any similarities between the necrosis response and reaction zone. To investigate this, Norway spruce at different developmental stages (seedlings, young trees and mature trees) were challenged with Heterobasidion parviporum. Six major indicators were assayed: necrosis lesions, cell death, pH, reaction zone, reactive oxygen species (ROS) and expressions of defense-related genes (Per1, Per2, LAC, JAZ1, OPR, and STS2). Increased transcript levels of the following genes Per1, Per2, LAC and JAZ1 were documented in seedlings but higher expression of Per2 and LAC was recorded in mature trees. Results revealed that all infected tissues were strongly necrotic or had increased lesion size. This is accompanied by increasing pH units up to 6.0 similar to levels documented in the reaction zone. Furthermore, ROS-generating peroxidase activity increased in infected tissues compared to the control. All these changes were found to be similar to observations in the reaction zone of woody trees. However, cell death was only measured in seedling roots and the method needs to be optimized for woody tissues. Further tests are therefore required for the clarification of relationship between necrotic cell death in seedling plants and reaction zone responses in mature woody tissues.
  • Peltokangas, Kenneth (Helsingin yliopisto, 2016)
    Loppijärvi on Kanta-Hämeessä sijaitseva matala humusjärvi, jonka rehevöityminen on edennyt poikkeuksellisen nopeasti viimeisen kymmenen vuoden aikana. Useista hoito- ja kunnostustoimista huolimatta järven rehevöityminen on jatkunut voimakkaana ja tilannetta pidetään huolestuttavana. Järven veden laadussa tapahtuneista muutoksista vesikasvillisuudesta ja kalastosta on saatavilla paljon tutkittua tietoa. Sen sijaan järven pohjasedimentistä tiedetään hyvin vähän. Tämän pro gradu -tutkielman tavoitteena oli kartoittaa järven pohjasedimentin tilaa, luoda yleiskuva järven rehevöitymiseen vaikuttavista fysikaalis-kemiallisista ominaisuuksista sekä arvioida sedimentin kuormituspotentiaaliin vaikuttavien ilmiöiden merkitystä. Tutkimus koostui kahdesta osasta. Ensimmäisessä tutkittiin järven pohjasedimentin ominaisuuksia järven eri osista otettujen sedimenttinäytteiden ja niistä määritettyjen raudan, alumiinin, kalsiumin ja fosforin kokonaispitoisuuksien avulla. Toinen osa koostui muhituskokeesta, jossa tarkasteltiin sedimentin happitilan ja järvikunnostuksessa yleisesti käytetyn alumiinikloridin vaikutuksia sedimentin sisältämän fosforin pidättymiseen ja jakautumiseen sekä arvioitiin sen soveltumista järvikunnostukseen laboratoriomittakaavassa. Sedimenttitutkimuksen perusteella Loppijärven nykyinen rehevöitymiskehitys johtuu sisäisestä kuormituksesta, eikä järveen kohdistu kuormitusta pistemäisistä lähteitä. Loppijärven sedimentin Fe:P-suhde vaihteli välillä 15–30. Sedimentin fosforipitoisuus oli noin 2,1 g P kg-1 koko sedimenttiprofiilin syvyydellä ja Fe:P-suhteen vaihtelu johtui pääasiassa sedimentin rautapitoisuudesta. Tulosten perusteella sedimentin fosforinpidätyskyky ei vastannut Fe:Psuhdetta, mikä viittaa muiden tekijöiden vaikuttavan raudan kykyyn pidättää fosforia. Muhituskokeen perusteella alumiinikloridikäsittely ei soveltunut sitomaan fosforia alumiinin aiheuttaman happamoitumisen takia. Alumiinikloridikäsittelyn vaikutus fosforin käyttäytymiseen vaihteli näytteiden hapetustilasta riippuen. Tulosten perusteella rauta sääteli fosforin vapautumista sedimentistä ja paras tulos kunnostustavoitteiden kannalta saatiin hapellisissa olosuhteissa ilman alumiinikloridikäsittelyä. Sedimenttitutkimuksen perusteella kemikaalikäsittelyt voivat auttaa kunnostustavoitteiden saavuttamisessa, mutta rehevöitymisen pysäyttäminen vaatii toimenpiteitä, jotka vaikuttavat sedimentissä vallitseviin olosuhteisiin tai sisäistä kuormitusta sääteleviin prosesseihin.
  • Markkula, Anniina (Helsingin yliopisto, 2016)
    New products are being introduced to the markets constantly and a big portion of them fail within the first few years of launch (Sivadas & Dwyer 2000). Lack of market understanding is a commonly mentioned cause of new product failure (Baker & Hart 1999, 356). Dynamic launch strategies allow for changes to be made to the launch strategy based on market information at the time of the actual launch in attempt to improve the success of it. New technologies offer new ways of interacting with consumers and acquiring timely consumer and market information. This thesis looked at the perquisites that affect the usability of QR codes as a way to acquire consumer information during a dynamic new product launch. Cui et al. (2011) dynamic model of a new product launch was used as the basis of the theoretical framework of the study. An online survey was constructed with questions on factors affecting consumers’ willingness to use QR codes on a new product package and factors affecting their willingness to give personal information through a QR code. The survey yielded 104 responses that were statistically analyzed using IBM SPSS modeler. The findings of the study suggest that perceived ease of use of QR codes has an effect on consumer’s likelihood of scanning codes. In addition to ease of use there needs to be relevant incentives for consumers to be willing to scan QR codes and give personal information. Findings suggest that opportunity to receive a discount coupon, acquire more information about a product or an opportunity to give feedback about the product could work as incentives for scanning a QR code on a new product package. These were not however seen as strong incentives for giving personal information, indicating that stronger benefits are needed to motivate consumers. This study gives insight into the usability of QR codes, but the skewed demographic background of the respondents and limited findings related to incentives of giving personal information indicate that more research is needed on the topic.
  • Kataja, Elina (Helsingin yliopisto, 2016)
    The effects of three rootstocks, B9, MTT1 and MTT5 on yield and fruit quality in ‘Heta’ apple were studied. Observations were done (1) at harvest, (2) four weeks after harvest and (3) six weeks after harvest. Number of fruits per tree was greater on B9 than on MTT5. Fruit ripening was slower on MTT5 than on B9 and MTT1. Streif index and starch content based on iodine test were higher on MTT5 than on other rootstocks. At harvest fruit on MTT5 were firmer than on B9. Firmness decreased on all rootstocks, but after four weeks after harvest it continued to decrease only on MTT5. Fruit dry mass content four weeks after harvest was higher on MTT1 than on MTT5. Dry mass content did not change during storage. Sugar-acid ratio was higher four and six weeks after harvest in fruits on B9 than in fruits on MTT1 and MTT5. Four weeks after harvest fruit on MTT1 had higher TA (titratable acids) content than on B9. Brix was much higher on MTT1 than on MTT5 both at harvest and four weeks after harvest. There was much more boron (B) and iron (Fe) in fruit on MTT5 than on B9 and MTT1. Sulphur (S) content was smaller on MTT1 than on other rootstocks. Zinc (Zn) content was lower on MTT1 from that on other rootstocks. Rootstock had no effect on fruit calsium (Ca), magnesium (Mg), phosphorus (P), copper (Cu), manganese (Mn) and kalium (K) content. Possibly due to young age of the trees (three years after planting) rootstock had no effect on fruit coloring (L, a, b, chroma, hue). In conclusion rootstock B9 stood out positively due to greater number of fruits per tree, early ripening and sweeter fruits, but further research is needed.
  • Launto, Antton (Helsingin yliopisto, 2016)
    Kiinnostus lähiruokaa kohtaan on kasvanut kuluttajien keskuudessa merkittävästi. Lähiruoasta puhutaan paljon ja sitä myös halutaan ostaa. Kuluttajat ovat entistä kiinnostuneimpia siitä, mistä heidän ostamansa ruoka on peräisin. Tämä lähtökohta antaa tuottajille uudenlaisia mahdollisuuksia toimia markkinoilla. Tuotteiden myynti asiakkaille ilman tukkuliikkeitä ja ylimääräisiä välikäsiä on helpottunut huomattavasti, sillä asiakkaat haluavat ostaa elintarvikkeita suoraan tuottajalta. Ketju pellolta pöytään jää tämän seurauksena lyhyeksi, mutta uudenlainen konsepti asettaa tuottajille myös uudenlaisia haasteita. Tässä tutkimuksessa tutkittiin, miten sauvolaiset perunantuottajat toimivat lähiruokamarkkinoilla ja ovatko heidän toimintatavat ja toimintaympäristö muuttuneet lähiruokatrendin seurauksena. Tutkimuksessa selvitettiin, onko tuotteiden markkinointi helpottunut lähiruoan kysynnän kasvaessa. Tutkimus tehtiin tuottajan näkökulmasta ja sen lähestymistavaksi valittiin kvalitatiivinen tutkimusote. Haastattelut, jotka tuottajille tehtiin, toteutettiin teemahaastatteluina. Haastatellut tuottajat myyvät perunaa Turun seudulle ja haastateltavien joukossa on perunaa eri vuodenaikoina myyviä henkilöitä. Vuodenajasta riippumatta asiakkaat ovat kiinnostuneita lähiruoasta. Tutkimustulosten mukaan tuotteiden myynti on muuttunut helpommaksi lähiruokabuumin seurauksena ja asiakkaat ovat entistä kiinnostuneempia yhteistyöstä paikallisten tuottajien kanssa. Suurin yhteistyökumppani kaikilla tuottajilla on vähittäiskauppa. Lähiruokatoiminta vaatii tuottajilta paljon. Toimintaan on sitouduttava ja toiminnan on oltava jatkuvaa. Myytävän tuotteen laadusta on pidettävä huolta ja asiakkaan toivomuksia on kuunneltava tarkasti.
  • sirviö, riikka (Helsingin yliopisto, 2016)
    The consequences of tropical forest degradation and deforestation have gained global political attention due to their contribution on climate change and biodiversity loss. Forest degradation and deforestation are also having impacts on local peoples living in the forests. Reducing Emissions from Deforestation and Forest Degradation (REDD+) and European Union Action Plan on Forest Law Enforcement, Governance and Trade (FLEGT) including its Voluntary Partnership Agreements (VPAs) are two prominent efforts towards reducing the loss of tropical forests. Even though they have different implementation strategies, they both reach for positive change in governance. They are facing similar challenges including corruption, legality of land allocation and lack of secure tenure. Noticeably secure tenure is associated with most of the governance challenges. Several forest rich tropical countries such as Cameroon are participating in these processes to sustainably manage their forests. In Cameroon the rapid population growth together with growing global need for natural resources are driving unsustainable and illegal actions in forest sector. This master’s thesis examines how are REDD+ and FLEGT are contributing on forest governance and securing tenure rights of local peoples, how secure tenure can affect the implementation of the REDD+ and FLEGT processes and in what extent should the tenure rights be transferred to locals to achieve the goals of the REDD+ and FLEGT. The empirical research is conducted through analysing policy documents and literature as well as interviewing officials and local peoples in Cameroon. The main results are that in Cameroon there are no real political will to address the forest loss, and the local peoples have very little role on protecting their livelihood even though it would be important for them and also for the processes of REDD+ and FLEGT. Also, the government of Cameroon gives a little role for REDD+ and FLEGT in the governance of forest resources. So far, the processes have not had significant influence on tenure condition in Cameroon. The recommendations of this study is for REDD+ and FLEGT to concentrate more on education especially in local level since the lack of understanding is hindering the development of both processes. The collaboration and greater transparency between REDD+ and FLEGT would be crucial for their success.
  • Alexanova, Anna (Helsingin yliopisto, 2016)
    Long QT syndrome, LQTS, is a congenital or acquired cardiac disorder characterized by prolonged cardiac repolarization phase. It is observed as a prolonged QT period in electrocardiodiagraph and can cause life-threatening specific ventricular tachycardia, torsades de pointes. Hundreds of mutations in 15 genes (LQT1-15) are linked to congenital LQTS. Worldwide prevalence of congenital LQTS gene mutations is from 1:2000 to 1:5000. However, the prevalence in Finland is much higher due to four founder mutations that alone occur in one out of 250 individuals. Acquired LQTS is often drug-induced and the most common cause for the withdrawal of drugs on the market. Carriers of LQTS mutations are more susceptible to acquired LQTS than normal population. LQTS-specific cardiomyocytes can thus provide a thorough model for drug cardiotoxicity screening, better insight into disease mechanisms and assist in drug development. This thesis was a part of a bigger project concentrating on validation of LQT2-specific cell lines that could be used for the purposes mentioned above. Induced pluripotent stem (iPS) cell technology enables creation of disease-specific pluripotent stem cell lines, which can be differentiated into any cell type. In this thesis, two LQT2-specific iPS cell lines derived from a clinically symptomatic 44-year-old female were used. She is heterozygous for Finnish founder mutation L552 in KCNH2 gene, which encodes the α-subunit of the cardiac rapidly activating potassium rectifier channel. iPS cells were first verified to express pluripotency markers and to form embryoid bodies containing all germ layers. iPS cells were then differentiated into cardiomyocytes by culturing them with END-2 cells and mechanical beating of the cardiomyocytes was assessed from video recordings. Single LQT2-specific cardiomyocytes showed LQT2-related phenotype in vitro with 43% of single LQT2 cardiomyocytes showing abnormal beating patterns and prolonged contraction time. This phenotype was rescued in LQT2-specific cardiomyocyte clusters. Finally, the expression ratios of wild type and mutated KCNH2 alleles were compared between cardiomyocytes derived from the female and her son, a carrier of the same mutation but with asymptomatic phenotype. Cardiomyocytes from both individuals expressed KCNH2 alleles with the ratio between 1:2 and 1:1 (wt:mut), thus allelic imbalance does not explain differences in the clinical phenotypes. All in all, the results of this thesis suggest that after further validation, mainly electrophysiology studies, these cell lines are most likely suitable to be applied for disease modeling, cardiotoxicity screening and finding new therapies for LQT2.
  • Järveläinen, Anni (Helsingin yliopisto, 2016)
    Tutkielman kirjallisuuskatsauksessa tarkasteltiin ruoan valintaan vaikuttavia tekijöitä, joista erityisesti keskityttiin brändiin, emootioihin ja asenteisiin. Tämän lisäksi käsiteltiin, kuinka valintaan vaikuttavia tekijöitä voidaan mitata ja kuinka niillä on ennustettu valintaa. Tutkimuksen tavoitteena oli selvittää tuoteinformaation vaikutusta ostovalintaan välipalatuotteilla ja selvittää, mikä käytetyistä mittausmenetelmistä ennusti ostamista parhaiten. Tutkittavina tuoteryhminä olivat maustamattomat jogurtit ja maustetut proteiinirahkat, joiden arvioinnissa koehenkilöinä olivat tuotteiden käyttäjät. Koehenkilöt (jogurtti n=105; rahka n=107) arvioivat tuotteiden miellyttävyyttä (7-portainen asteikko), niiden herättämiä emootioita (12 kpl, joista 6 positiivista ja 6 negatiivista kuvana ja tekstinä) ja ostotodennäköisyyttä (5-portainen asteikko) neljällä eri määrällä tuoteinformaatiota: pelkällä bränditiedolla, brändin ja pakkauksen kanssa, sokkomaistona sekä brändimaistona, jossa maistamisen yhteydessä oli brändi- ja pakkaustiedot nähtävillä. Emootiot mitattiin vain kahdessa viimeisessä. Arviointien jälkeen koehenkilöt ilmoittivat ostoistaan kahdesti kuukauden aikana. Tutkimuksessa oli kolme osaa: ennakkokysely, aistinvarainen tuotearviointi ja seurantakysely. Tuotteiden ominaisuuksista tärkeimpinä pidettiin makua ja terveellisyyttä. Lisäksi brändin ja pakkauksen todettiin vaikuttavan annettuihin arviointeihin positiivisesti tai negatiivisesti. Tuotteiden miellyttävyysarviot, heränneet emootiot ja ilmoitettu ostotodennäköisyys vaihtelivat sen mukaan samansuuntaisesti, kuinka paljon kuluttajalla oli tuoteinformaatiota saatavilla. Ostamista selittivät parhaiten mittaukset, jotka oli tehty joko pelkällä brändi- ja pakkaustiedoilla (jogurtti) eli tuoteinformaation määrällä, joka on sama kuin kaupassa ostohetkellä, tai maku-, brändi- ja pakkaustiedot yhdessä (rahka), eli kun saatavilla oli kaikki mahdollinen tuoteinformaatio. Huonoiten ostamista selitti sokkomaisto, jossa arviot perustuivat vain aistinvaraiseen informaatioon. Tämän perusteella pelkällä tuotteen aistittavalla miellyttävyydellä ei voida ennustaa ostamista ja ruoan valintaa, ainakaan tässä tuotekategoriassa. Ostamista voidaan ennustaa parhaiten kysymällä kuluttajan itse arvioimaa ostotodennäköisyyttä. Kuitenkin miellyttävyys voi antaa tuotteesta syvällisempää informaatiota kuin pelkkä ostoaikomus. Tässä tutkimuksessa mittareita oli käytetty peräkkäin, mikä voi lisätä niiden keskinäistä korrelaatiota ja saada ne näin näyttämään mittaavan samaa asiaa enemmän kuin todellisuudessa mittaavat.
  • Sun, Mengyi (Helsingin yliopisto, 2016)
    As the sustainable energy is becoming increasingly important, utilization of lignocellulosic biomass for biofuel production is the central part of this area. Fungal enzymes play an important role in lignocellulose degradation. Glucuronoyl esterase (GE) is a less studied fungal enzyme which degrades the ester linkage between lignin alcohol and hemicellulose side chain 4-O-methyl D-glucuronic acids. Genes encoding GE have been identified from various fungal species and they have been expressed in different production systems to be able to study their biochemical properties in detail. The gene encoding GE from the basidiomycete litter-decomposing fungus Stropharia coronilla was cloned and heterologous expressed in Pichia pastoris yeast. The expression and secretion of GE was induced by growing S. coronilla on lignocellulose supplemented cultivations. ScGE activity can be detected after the fifth day cultivation and it peaked on the 14th day. The heterologous expression of ScGE in P. pastoris showed that ScGE was produced as an enzymatically active protein. The commercial K-URONIC kit supplemented with a GE specific substrate benzyl-D-glucuronate was used to determine GE activity.