Maatalous- metsätieteellinen tiedekunta


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  • Koivunen, Erja (Helsingin yliopisto, 2016)
    Four experiments were conducted to find appropriate inclusion levels of pea (Pisum sativum L.) and faba bean (Vicia faba L.) (FB) seeds as a substitute for soybean meal (SBM) in poultry diets. The inclusion levels tested for pea (cv. Karita) were 100, 200 and 300 g/kg in layer diet and 150, 300 and 450 in broiler diet and for FB (cv. Kontu) 50 and 100 g/kg in layer diet and 80, 160 and 240 g/kg in broiler diet. The effect of a specific enzyme cocktail for improving the nutritive value of wheat-pea diets was also investigated in broilers. The fifth experiment was conducted to determine the apparent metabolizable energy (AME) value and the coefficients apparent ileal digestibility (CAID) of nutrients of the seeds of two peas (cv. Karita and cv. Sohvi), two FBs (cv. Kontu and cv. Ukko), and one blue lupin (Lupinus angustifolius) (cv. Pershatsvet) in broilers. Each grain legumes contained less protein than soybean SBM did. Pea inclusion up to 300 g/kg had no effect on egg production or egg quality. Pea inclusion of 150 g/kg improved the growth of broilers, while pea inclusions 300 and 450 g/kg had no effect on growth. Feed conversion ratio (FCR) of broilers was similar between control treatment and treatment with pea inclusions 450 g/kg. The use of enzyme cocktail improves the nutritive value of wheat in the diet. FB inclusion decreased egg weight. Egg mass production decreased and FCR increased when FB proportion increased. FB inclusion had no effect on egg quality. Broilers growth and feed consumption decreased and FCR improved in a linear manner along FB inclusion. The CAID of protein was higher in peas and lupin than in FB cv. Kontu. Most of CAID values of amino acids (AA) followed the pattern shown by the CAID of protein. AAs in peas were well digested. The AAs were averagely digested in FBs with the exception of cysteine, which was poorly digested. The AAs were averagely digested in lupin. The AME for pea cv. Karita was higher than those of pea cv. Sohvi and FBs cv. Kontu and cv. Ukko. Lupin had the poorest AME. In conclusion, grain legumes can partially replace SBM in poultry diets. However, they replace also cereals in diets. Peas (cv. Karita) can be used at least up to 300 g/kg in layer diets and 450 g/kg in broiler diet. The use of FB (cv. Kontu) is recommended to be limited to the content of 50 g/kg in layer diets and 160 g/kg in broiler diets.
  • Korkalo, Liisa (Helsingin yliopisto, 2016)
    Poor micronutrient intake and status (also called hidden hunger ) may compromise the health and work capacity of adolescent girls. In Mozambique, a low-income country with a high rate of adolescent pregnancies, girls poor micronutrient status is also an important risk factor for maternal and child mortality, adverse birth outcomes such as low birth weight, and impaired cognitive performance of the child. The main aims of this thesis were to examine the diet and micronutrient status of adolescent girls in Central Mozambique and to study whether dietary diversity is associated with biomarkers of micronutrient status. The thesis also includes a methodological study assessing the validity of using food photographs in portion size estimation in adolescent Mozambican girls. The validity study on food photographs was conducted in 2009. Two local staple foods and three sauces were selected as test foods and photographs of three different portion sizes were produced for each of them. The participants (99 Mozambican girls aged 13-18 years) were served weighted food portions, and after eating their meal, they were interviewed and asked to estimate the size of their portions with the help of the food photographs. The findings of this study indicated a tendency towards under-estimation of portion sizes. On the group level, the results were acceptable, but large variation in the accuracy of individuals estimates was found. The ZANE Study was conducted in 2010. It was a population-based cross-sectional study on the diet and nutritional status of 14- to 19-year-old girls in Zambézia Province. The study regions included one urban area and two rural districts. Two separate samples of girls were recruited: the first in January-February ( hunger season , n=283) and the second in May-June (harvest season, n=268). A 24-hour dietary recall interview and a seven-day food frequency questionnaire interview were conducted for each participant. Blood and urine samples were collected and blood haemoglobin, serum ferritin, serum zinc, serum selenium, urinary iodine, plasma retinol and serum folate concentrations were analysed. The ZANE Study revealed a low median energy intake calculated from the 24-hour recalls [5.2 MJ/day, interquartile range: 3.6, 7.4 (calculated using sampling weights); n=543]. This is in line with the findings of the validity study and is at least partly explained by under-reporting. Low intakes of several micronutrients and relatively high phytate:zinc molar ratios, typical for diets in low-income settings, were found. Marked seasonal variation was noted for vitamin A intake. According to the World Health Organization definitions, anaemia was a severe public health problem and vitamin A deficiency a moderate public health problem. The serum ferritin concentrations indicated that iron depletion was prevalent in the population. The population was also found to have a risk of zinc deficiency. Folate status was considered to be generally adequate, but an exception to this was the low serum folate concentrations in the urban area in May-June. Mild to moderate iodine deficiency was found in the rural districts, whereas the iodine status of urban girls was adequate. Selenium status was considered adequate. In the last part of the thesis, associations between dietary diversity and low concentrations of haemoglobin and serum/plasma ferritin, zinc, retinol, and folate in non-pregnant girls (n=227 in January-February and n=223 in May-June) were examined in logistic regression models using three different dietary diversity scores. First, the Women s Dietary Diversity Score (WDDS), consisting of nine food groups was calculated from the 24-hour recalls according to instructions by the Food and Agriculture Organization of the United Nations. The second score employed a minimum portion size limit of 15 g (WDDS15g), and the third was based on the seven-day food frequency questionnaires (7dWDDS). The most consistent findings of this work were the associations observed for zinc. In January-February, after adjusting for confounders, a low (≤3) WDDS and a low (≤5) 7dWDDS were each associated with higher odds of having lowserum zinc (≤25th percentile of the season-specific distribution) compared with having a higher score. These associations were not present in May-June. In conclusion, using food photographs in portion size estimation in adolescent Mozambican girls showed an acceptable level of validity. There was, however, a tendency towards under-reporting. In the future, producing and testing more comprehensive sets of locally relevant food photographs will be useful for dietary studies in Sub-Saharan African settings. Hidden hunger was found to be a public health problem among adolescent girls in Central Mozambique. Actions are needed to prevent and control hidden hunger, especially with regard to low iron, zinc, iodine, and vitamin A status. Programmes may need to be tailored according to urban-rural differences in diet and micronutrient status. Some associations between dietary diversity and micronutrient status may exist, especially in the case of zinc. However, the associations seem to be season-specific, which may limit the practical application of dietary diversity scores as tools to identify populations at risk of low micronutrient status.
  • El Sayed Bashandy, Hany (Helsingin yliopisto, 2016)
    The flavonoid biosynthetic pathway and flavonoid metabolites have been extensively studied because of their biological roles in plant and animal kingdoms. Flavonoid metabolites are involved in plant resistance, UV-protection, pollinator attraction and have antioxidant effects. Plant species synthesise a large number of secondary metabolites, including flavonoids, carotenoids and others. Flower colour is an important feature for marketing of the ornamental model plant gerbera (Gerbera hybrida). In gerbera, flavonoid metabolites accumulate in the adaxial epidermal layer of flower petals and lead to different flower colours and patterns. These metabolites consist of three subgroups, flavones, flavonols and anthocyanins in gerbera, which have also been used to characterize different cultivars. The cultivars show variation in flower colour according to their anthocyanin type. The acyanic gerbera cultivars have flavonoid profiles comparable to the cyanic cultivars, except for the synthesis and accumulation of specific anthocyanins. Metabolite profiles indicated that all analysed acyanic cultivars have a block in a late stage of the anthocyanin pathway. Ivory, a sport of the pelargonidin-cultivar Estelle, has white flowers. Ivory has flavones and flavonols, but no anthocyanin. Gene expression of all flavonoid pathway genes was similar in Estelle and Ivory. However, both cultivars have two different alleles encoding dihydroflavonol 4-reductase and in Ivory one of them (GDFR1-2) was found to have a point mutation resulting in inactivation of the encoded enzyme. Still, Ivory expresses the second allele (GDFR1-3) and accumulates active DFR enzyme. The cyanidin cultivar President expresses only the GDFR1-3 allele, but cannot synthesize pelargonidin. Therefore, GDFR1-2 contributes specifically to pelargonidin biosynthesis and GDFR1-3 to cyanidin biosynthesis. This could be explained by a coordinated biosynthesis of anthocyanins in multi-enzyme complexes, metabolons. Gerbera chalcone synthases (GCHSs) belong to the superfamily of Type III polyketide synthase enzymes. GCHS1, 3 and 4 have different contributions to the flavonoid pathway, according to the tissue specific and post-transcriptional regulation. RNA interference of CHS encoding genes was used in different gerbera cultivars to show that GCHS1 has the main contribution to anthocyanin accumulation in petal tissues. GCHS4 was strongly expressed in petals but did not lead to anthocyanin accumulation. Still, GCHS4 is expressed and encoded a functional enzyme in the vegetative tissues.
  • Rasimus-Sahari, Stiina (Helsingin yliopisto, 2016)
    Humans are exposed to microbes and microbial compounds continuously via environmental exposure and food in addition to our own microbiome. This thesis reports new empirical findings concerning the types of mitochondrial toxins present in food and indoor air and the effects of these toxins on mammalian cells. Dust and aerosolized compounds collected from moisture-damaged buildings were shown to have mitochondriotoxic effects detectable with a boar sperm motility inhibition (BSMI) assay. Toxin-producing bacteria isolated from the dusts and aerosols included producers of the mitochondrial toxins amylosin, cereulide, and valinomycin. In addition, aerosolized valinomycin and toxic chemical compounds emitted from building materials were detected using boar spermatozoa, demonstrating that the BMSI assay could be used to screen for mitochondrial toxicity in indoor air. Amylosin, a mitochondriotoxin produced by Bacillus spp. from indoor air and food, was shown to be immunotoxic: exposure of human primary macrophages to nanomolar concentrations of amylosin stimulated the release of inflammatory cytokines interleukin 1β and interleukin 18. Amylosin is the first bacterial channel-forming ionophore toxin reported to have this effect. Low amounts of amylosin caused significant dose-dependent potassium ion efflux from human somatic cells and boar spermatozoa. Potassium efflux may be the trigger causing the observed cytokine release from macrophages after amylosin exposure. Amylosin also displayed antifungal and antibacterial activity which may give its producers a competitive advantage in mixed microbial communities. Two previously unreported food safety hazards were identified from cereal grains. A novel heat-stable mitochondrial toxin named paenilide, similar to cereulide biochemically and in mode of action, was found to be produced by Paenibacillus tundrae isolated from barley grains. This finding shows that the genus Paenibacillus cannot be considered harmless for human health. Paenilide consisted of two components with molecular masses equal to those of cereulide and homocereulide but with longer chromatographic retention times, indicating more hydrophobic structures than those of the cereulide compounds. Paenilide acted as a lipophilic potassium ionophore, causing depolarization, swelling, uncoupling of oxidative phosphorylation, and loss of respiratory control in isolated rat liver mitochondria. Paenilide accelerated glucose consumption in porcine kidney epithelial cells, causing metabolic acidosis, and was cytotoxic to porcine and murine cells. Paenilide was as toxic as cereulide at nanomolar amounts, making it a possibly potent food poisoning agent. Paenilide was produced at incubation temperatures down to +5°C, indicating potential toxin formation in chilled foods. The second novel finding connected to cereal grains was the discovery of toxin-producing Streptomyces spp. in healthy-looking grains of barley and spring wheat. The barley grain isolates, belonging to the Streptomyces albidoflavus group, produced the mitochondriotoxic macrolide antimycin A, a known disrupter of oxidative phosphorylation. The cause of the mitochondrial toxicity of the spring wheat grain isolates, most closely related to Streptomyces sedi, remained unidentified. The toxicity of the isolates and grains was detected using the BSMI assay, which was sensitive enough to detect nanomolar contamination corresponding to 2 ng of antimycin A per barley grain. Antimycin A was more toxic towards porcine kidney epithelial cells than the mycotoxin enniatin B but less toxic than cereulide or paenilide. Exposure of porcine kidney epithelial cells to these four toxins accelerated glucose consumption and caused mitochondrial depolarization, indicating upregulation of glycolysis. Pancreatic insulin-producing beta cells, however, are not able to switch to glycolytic ATP production and undergo necrotic cell death upon exposure to mitochondrial toxins. Thus, consumption of grains contaminated with mitochondrial toxins may especially affect pancreatic functions. In conlusion, the results of this thesis show that chronic exposure via indoor air or food to sub-lethal concentrations of mitochondriotoxins produced by spore-forming bacteria may be more common than known so far. This exposure may connect to the increasing worldwide incidence of western lifestyle diseases, such as diabetes, asthma, and allergies as well as cardiovascular and neurological disorders. The studied toxins are all heat-stable and produced by spore-formers able to withstand harsh environmental conditions, highlighting that preventing their presence and endurance in food and indoor environments is problematic.
  • Heikkinen, Susanna (Helsingin yliopisto, 2016)
    Cereal arabinoxylans (AXs) belong to the heterogeneous group of hemicelluloses. They are branched polysaccharides located in the plant cell wall, where they strengthen the cell wall together with cellulose and lignin. AXs vary in their molecular structure depending on the plant source from which they are extracted. Cereal AX can be extracted, for example, from the side streams of cereal processing such as bran, husks/hulls, and straw. AXs are sustainable raw materials with a film-forming ability; they can therefore be utilized more efficiently in biodegradable packaging and coatings. In this thesis, structurally different cereal-based AXs were used in the film studies. The effect of the type and amount of polyol plasticizer on the film properties as well as their storage stability during four and five months time was investigated with oat spelt arabinoxylan (OsAX). The structure function relationship of AXs in films was studied by comparing differently substituted rye and wheat flour arabinoxylan (RAX and WAX, respectively) and was further investigated by using specific arabinofuranosidases to tailor arabinose to xylose ratios and arabinose substitution patterns of RAX and WAX. The usability of crude biomass extracts in larger-scale film/sheet preparation was studied via the sheet extrusion of two wheat bran extracts (WBEs), which contained similar amounts of AX and lignin, whereas their starch and protein contents differed depending on the purification process. The film and sheet properties, such as mechanical and barrier properties as well as crystallinity and the physical state of the films, were investigated in order to evaluate the suitability of these materials for packaging. This study revealed that AX, having relatively low arabinose substitution and molar mass, such as OsAX, in general needs plasticization for cohesive film formation. It was found that the amount and type of plasticizer clearly affects the tensile and permeability properties of the films as well as their water sensitivity. In general, the sorbitol-plasticized films were stronger and had lower water vapor permeability (WVP) and oxygen gas permeability (OP) than the films plasticized with glycerol. Structure correlation studies carried out with RAX and WAX showed that the AXs fine structure affects film formation and film properties. With specific enzymatic tailoring, it was observed that the Ara/Xyl ratios of RAX and WAX did not contribute alone to the behavior of AXs in the films; instead, both the amount and distribution of arabinose side units in the xylan chain had a high impact on the results. When the number of un-substituted xylose units was high, the water solubility of AX decreased and the formed films had a semi-crystalline structure. Mild de-branching improved some film properties, for example, the tensile strength of the RAX films increased. Additionally, it was observed that the OP of the RAX and WAX films decreased along with the de-branching. A storage study showed that the polyol-plasticized OsAX film properties changed during storage; possible reasons for this were lowered plasticization caused by glycerol migration out from the film matrix and/or formation of heterogeneous structures in the film with plasticizer-rich and polymer-rich areas. The WBEs turned out to be potential raw materials in the up-scaled sheet preparation method, which was carried out with a single-screw extruder. Both of the extracts that were studied formed cohesive sheets with polyol addition. In this study, all of the AX films showed low OP properties, which were further decreased by lowering the Ara/Xyl ratio or with plasticized films by decreasing the polyol content. Thus, AX films can be thought of as a potential choice for those applications where high oxygen barrier capacity is needed to prevent the oxidative deterioration of the packaged food product. Present study on AXs fine structure gave information that can be used when various structurally different agricultural side streams are considered as raw materials for film applications. In the current study, the main challenge of the AX films and sheets was their water sensitivity, and with the plasticized films, their decreased storage stability. The sheet extrusion results proved that highly purified fractions are not essential in material production; instead, in this study, moderately purified fractions with a high starch and low protein content formed strong sheets with lowered water sensitivity.
  • Rimhanen, Karoliina (Helsingin yliopisto, 2016)
    Sub-Saharan Africa (SSA) is one of the world´s most vulnerable regions to climate change. Even though the proportion of greenhouse gas emissions produced in SSA is low, the agricultural sector has an enormous potential for climate change mitigation. The aim here is to increase understanding of the potential of climate change mitigation to enhance food security. The focus of the study is to identify the determinants of this potential, to estimate the possibilities to increase the proportion of carbon ending up in soil and to quantify the soil carbon sequestration potential of agroecological practices in Ethiopia. Identification of the determinants of the potential of climate change mitigation to enhance food security was based on in-depth interviews and focus group discussions. The assessment of carbon flows was based on interviews and sampling. Material flow analysis and carbon balance counting was used for tracking the carbon flows and for estimating the carbon losses. Quantification of the carbon sequestration potential of the agroecological practices was based on comparison of the existing plot pairs, including a plot with an agroecological practice and an adjacent plot with a traditional practice. Soil carbon sequestration in agricultural soil was considered as the most important means to promote climate change mitigation and to enhance food security. The primary factors enhancing food security were perceived to be increasing agricultural productivity and incomes from marketed crops. On the Ethiopian farms, 8 12% of the total harvested carbon was used for soil and 9 16% for food. The largest carbon losses were due to biomass burning and livestock metabolism. The proportion of carbon used for soil could mainly be increased by reducing gaseous losses. Agroforestry led to 11.4 t ha-1, restrained grazing to 9.6 t ha-1 and terracing to 1.7 t ha-1 greater soil carbon stock than did their control plots. The estimates are higher than those based on process-modelling studies. The difference probably resulted from the development and validation of process models under conditions that differ from those in East-Africa. From the results it can be concluded that the most important means perceived as enhancing food security through climate change mitigation is improving food availability through soil carbon sequestration. The proportion of carbon used for energy determines the proportion ending up in soil. Alternative energy sources are needed to increase the flow of carbon to soil. The soil carbon sequestration potential in Ethiopian agriculture is greater than previously estimated. Climate conditions and intercropping treatment should be incorporated into process models to improve their adequacy for farming systems in East Africa.
  • Oghenekaro, Abbot (Helsingin yliopisto, 2016)
    The white rot pathogen, Rigidoporus microporus (Basidiomycota) syn. Rigidoporus lignosus is the most destructive root pathogen in rubber plantations located in South East Asia and Africa. Most management practices for the disease have been carried out without adequate knowledge of the population genetics of the pathogen. Our primary objective in the first part of this work was to characterize isolates from rubber trees (Hevea brasiliensis) in Nigeria. The lack of global studies comparing isolates from Asia and Africa where the majority of rubber plantations are located necessitated extending our molecular phylogeny studies to include isolates from other regions of the world. We compared the Nigerian isolates with isolates from South East Asia and Central/South America. Forty isolates were analyzed by sequencing four gene regions: the nuclear ribosomal DNA ITS and LSU, β-tubulin and translation elongation factor 1-α (tef1) genes. The isolates form three distinctive clades corresponding to Africa, South East Asia and South/Central America. There was high intra-species variation within each clade, but no geographic pattern was detected among the Nigerian isolates and also among the West and Central African isolates. Our multi-gene molecular phylogenetic analysis suggests the presence of two distinctive species associated with the white rot disease. Phylogenetic analysis also placed the Rigidoporus genus within the Oxyporus clade of the Hymaenochataeles. This study supports the need for a thorough revision of the Rigidoporus genera within the Polyporales/Hymaenochataeles. To gain insights on the saprotrophic abilities of Rigidoporus microporus isolates associated with the white rot disease of rubber trees, we performed wood decay tests of selected isolates on rubber wood blocks. We included a non-pathogenic endophytic South American isolate for comparative analysis. The structural alterations caused due to fungal growth in the rubber wood blocks was also studied. The pathogenic isolates associated with rubber trees significantly decayed the rubber wood blocks suggesting a capacity to switch to saprotrophic growth when the tree is killed. The non-pathogenic isolate had very low saprotrophic ability. Structural alterations of wood cell walls caused in the wood blocks were typical for white rot basidiomycetes. The fact that Rigidoporus microporus can switch to saprotrophic growth on dead cells of the tree led us to investigate the transcriptomic profiles of the fungus during growth on dead rubber wood. We performed RNA-Seq de novo transcriptomic assembly which produced 25, 880 annotated unigenes. The transcriptome expressed over 400 genes encoding lignocellulose enzymes. A number of glycoside hydrolases (GHs) were highly induced in rubber wood including all nine members of GH43 genes in the transcriptome. Twenty-four manganese peroxidase encoding genes were among a large number of oxidoreductases that were significantly up-regulated in rubber wood. Several genes involved in fatty acid and rubber latex degradation were expressed in the transcriptome. Several ABC transporters and hydrophobin genes were also expressed in the transcriptome. Finally, pathway enrichment analysis of genes related to energy metabolism revealed some genes including alcohol dehydrogenase with potential biotechnological applications. This is the first study on the transcriptomic analysis of R. microporus on rubber wood. The data generated should serve as a useful resource for future studies. Understanding how rubber tree is able to defend itself against invading Rigidoporus microporus was an additional research goal. The expression of defence-related genes; pathogenesis related proteins (PR1, PR3, PR5, PR8 and PR9), cell wall modification genes (PAL and expansin), signal transduction genes (ACC oxidase, AOC, MAPK) and a Myb transcription factor were studied in two clones (RRIM612 and PR107) of H. brasiliensis with different levels of susceptibility. Clone RRIM612 had a higher lesion size than clone PR107 after 5 weeks post inoculation with R. microporus. A class I chitinase (PR3) was up-regulated in RRIM612 in response to the pathogen while a class IV peroxidase (PR9) was highly up-regulated in PR107. Signal transduction genes involved in ethylene and jasmonic acid signaling as well as Phenylalanine ammonia-lyase (PAL) were up-regulated almost equally in both clones. The predicted expansin like protein was up-regulated 40 fold in RRIM612 in response to the pathogen. The results obtained demonstrate the variability in defence responses in the two clones studied and provides the first set of defence genes expression profiles of the host-pathogen interaction of the white rot disease of rubber trees. This study sheds light on the phylogeny of pathogenic Rigidoporus microporus isolates associated with the white rot disease as well as evidence showing its ability to switch to saprotrophic growth. The transcriptome of the fungus during saprotrophic growth was also de novo assembled revealing a vast number of lignocellulose degrading enzymes. Finally, this work provides an overview of potential candidate defence genes in H. brasiliensis in response to infection by R. microporus.
  • Keriö, Susanna (Helsingin yliopisto, 2015)
    During their life, conifers are attacked by fungal pathogens and insects. In the European forests, Heterobasidion annosum sensu stricto (s.s.) attacks Scots pine (Pinus sylvestris) roots, whereas Heterobasidion parviporum causes the majority of decay in Norway spruce (Picea abies), both causing severe economic losses. Another significant health problem of Scots pine is caused by Hylobius abietis, the large pine weevil, which damages newly established Scots pine stands. Several defence reactions in trees are activated upon fungal infection and insect attack, but these reactions have not been comprehensively studied in conifers. In this dissertation, the responses of mature Norway spruce and Scots pine trees to Heterobasidion spp. inoculation, and the responses of Scots pine saplings to Hylobius abietis feeding were studied. Also the ability of homokaryotic Heterobasidion spp. isolates to infect mature conifer hosts and elicit defensive responses was investigated. Terpene and transcript profiles of Scots pine to H. annosum s.s. and H. abietis challenge were studied, and a customised oligonucleotide microarray with 36.5K cDNA elements designed based on the P. taeda transcriptome was used to study the Scots pine transcriptome. The used homokaryotic Heterobasidion spp. isolates were able to colonize and evoke defence responses in the host trees with varying levels of susceptibility. Insect feeding and fungal inoculation induced terpene production in Scots pine. The results indicated that high accumulation of terpenes is not necessarily an effective defence against H. annosum, but δ-3-carene might be associated with higher tolerance to H. annosum in Scots pine. Only few genes related to terpene synthesis were induced in response to H. annosum infection and weevil feeding. Induction of genes related to biotic and abiotic stress responses indicated a wide transcriptomic reprogramming in response to fungal infection and weevil feeding. Genes related to signal perception and defence responses were induced especially in the trees less susceptible to H. annosum inoculation. In addition to these genes, Scots pine δ-3-carene synthases are promising candidates for further research on the Scots pine resistance to H. annosum.
  • Purkamo, Lotta (Helsingin yliopisto, 2015)
    Microbial life in the deep subsurface contributes significantly to overall biomass on Earth. Although the microbial communities inhabiting the deep subsurface are abundant, little is known about their diversity, activity, interactions and role in global biogeochemical cycles. The diversity of microbial life in the deep terrestrial subsurface of the Fennoscandian shield was studied with molecular biological methods. The Outokumpu Deep Drill Hole provides access to crystalline bedrock fluids that are estimated to be tens of millions of years old. Characterization of the indigenous bacterial and archaeal communities in addition to microbial communities with important functional properties in bedrock fluids was done from a depth range of 180 m to 2300 m. Microbial community profiling and assessment of possible functional processes was done with molecular fingerprinting, cloning and sequencing methods combined with suitable statistical and bioinformatics analyses. Low cell numbers but high diversity was characteristic to the microbial communities of the Outokumpu deep subsurface. The microbial communities in the fracture zones had in general fewer cells than those in the mixed fluids of the drill hole. Comamonadaceae, Peptococcaceae and Anaerobrancaceae were prevalent bacterial members of the microbial communities in the fracture fluids. Archaea were a minority in microbial communities. Sulfate-reducing bacteria and methanogens were detected at several depths. Microbial communities resembled those detected from other deep Fennoscandian Shield subsurface sites. Furthermore, sulfate reducing communities and archaeal communities resembled those found from the deep subsurface of South Africa. Investigation on carbon assimilation strategies of the microbial communities revealed that mainly heterotrophic Clostridia were responsible for CO2 fixation in this habitat. Representatives of Burkholderiales and Clostridia formed the core microbial community and these were also identified to be the keystone genera. The microbial communities of Outokumpu fractures share similarity with those of serpentinization-driven ecosystems. Energy and carbon substrates formed in serpentinization reactions of ophiolitic rocks in Outokumpu may sustain the microbial communities in this deep subsurface environment.
  • Aalto, Juho (Helsingin yliopisto, 2015)
    Boreal forests are the most significant source of volatile organic compounds (VOCs) in Northern Europe, emissions originating both from trees and forest floor. The VOCs are reactive trace gases that participate in chemical reactions in the atmosphere, thus affecting aerosol formation and climate. The overall aim was to characterize the temporal and spatial variability of VOC emissions and explain the processes and phenomena affecting those. Extensive field measurements were used, including both gas chromatograph and mass spectrometer as VOC analyzers. A dynamic enclosure method was utilized in measuring VOC fluxes from the forest floor and emissions from Scots pine shoots. The genetic background determines the blend of terpenoids emitted by Scots pine, thus having effect on the atmospheric composition. Forest floor and soil also has substantial effect on VOC fluxes on the ecosystem scale. In addition to the considerable spatial variation in VOC fluxes from the forest floor, there is variation of VOC emissions from Scots pine shoots; differences were associated with needle age, seasonality and growth processes. New foliage dominates the VOC emissions from Scots pine foliage during spring and early summer, when growth processes release significant amounts of VOCs, especially monoterpenes. Scots pine shoots are a strong source of monoterpenes during the early stages of photosynthetic recovery; these periods last from a couple of days to about one week and are likely related to the protection of evergreen foliage against photo-oxidative stress. The studies challenge the presumption of constant emission capacities, which is currently a common presumption in VOC emission inventories. Atmospheric concentrations of VOCs result from an output of the existing sources and their seasonal and spatial variation; this underlines the relevance and importance of details on large a scale. The findings provide new opportunities for developing VOC emissions models based on underlying physico-chemical processes.
  • Immonen, Aino-Maria (Helsingin yliopisto, 2015)
    This study investigates the manifestation of emotional influences in the context of two different instances of consumer food choice: price vs. ethicality trade-off decisions in everyday food purchase decision contexts, and the acceptance of genetically modified food products. This study has a particular emphasis on the intricacies that can be uncovered in the emotional influences, by putting focus on the unique compositions and motivational properties of different discrete emotions, and the anomalies and tensions that emerge when mixtures of emotions are experienced. The theoretical background of this study draws from emotion literature, previous research on consumer emotions, and consumer food choice. As a result of a literature review on these topics, this study proposes four key conceptual dimensions that need to be identified and defined in order to gain a better understanding of the role of discrete emotions in particular contexts of consumer food choice. The empirical investigation of this study was conducted with a quantitative approach. Two sets of consumer data (N = 855; 267) were acquired by means of survey questionnaires. The data were analysed with SPSS- and LISREL-softwares by using correlation analysis, analysis of variance, analysis of multiple mediation, moderation analysis, and structural equation modelling. The findings indicate that the salience of an explicit price vs. ethicality trade-off in food purchase decisions induces mixed consumer emotions. This emotionally ambivalent experience has an attenuating effect on the favourability of consumer responses to ethical food purchases with a premium price, but also to unethical food purchases that appeal to consumers with a low price. The findings also indicate that the specific combinations of discrete positive and negative emotions that arise in response to the two types of price vs. ethicality trade-offs are qualitatively distinct. This notion allows for identifying discrete emotional drivers that motivate and inhibit ethical and unethical food purchase decision-making among consumers, particularly when ethical product characteristics are being evaluated against the product price. The findings in the second empirical context of this study outline two distinguishable consumer response patterns to genetically modified (GM) food products, which are intertwined with consumers fearful and angry responses to the genetic modification of food (the GM of food). The findings indicate that the fear and anger that consumers experience towards the GM of food are rooted in different types of substantive concerns, and fearful and angry consumers have a preference for distinct modes of coping with the perceived threat of GM food products. The findings have implications for disentangling the nuances of the affectively toned consumer opposition that exists towards the GM of food and GM food products, and for interpreting their distinct impacts on the prospects of GM foods in the consumer market.
  • Korpunen, Heikki (Helsingin yliopisto, 2015)
    Finnish forest industry purchases 50 million cubic meters of wood annually. This means that the economic importance of the business is significant to forest owners. Sawmills, pulp and paper industry, and energy production are most common targets of the wood raw material. It is in mutual interest of both forest owners and the industry that the wood is allocated to right use according to the highest possible value-adding. The path of wood from forest to customers can be described as a value chain where the links are formed of harvesting and forwarding, long distance transportation, wood processing and energy use, and delivery to final customers. This dissertation focuses on the links of wood processing and energy use of the wood value chain by modelling production and costs of sawmill, pulp mill, paper mill, and combined heat and power (CHP) plant. The modelling was done by using activity-based costing (ABC), where the production is divided into processes and the production costs of each process are allocated to products or services according to resource consumption. Finally, all process costs are summed for total production costs of each cost object. The production and cost models were tested with virtual mills. The processes, the resources and the necessary cost factors of production were determined for test calculations. Finally, the capital, the labor, and the energy costs were allocated to the cost objects, which were both the raw materials and the end products. When comparing different mills and their production processes, it was noticed clearly that drying was an expensive process in sawmilling, pulping and papermaking. When focusing on cost factors of each mill, it was noteworthy that the sawing pattern affects the costs of a sawmill, energy production affects the costs of pulp and paper industry, and, likewise the utilization rate affects the combined heat and power plant. Profitability analyses were also made on the pulp mill, the paper mill and the CHP plant in varied market situations. One key finding was that in papermaking, the change of market price of paper was more significant to economics of the mill than a similar change in the market price of energy. The results of this dissertation can be used in estimating the economic performance of forest industry. Process-based approach helps in finding possible bottlenecks and in developing the production systematically. The findings of this study can also be used in finding the most profitable route for wood from the forest to customers.
  • Klimeski, Aleksandar (Helsingin yliopisto, 2015)
    Deterioration in the quality of surface waters worldwide is associated with losses of phosphorus (P) from diffuse sources. Controlling such losses is rather difficult, but their significance in reducing the effects of eutrophication is crucial. Phosphorus losses from diffuse sources represent a significant share of total P transfers to surface waters. Researchers have studied and implemented numerous methods to curb non-point P losses during the past decades, but such studies have generally been insufficient to change the impact of agriculture on the course of surface waters eutrophication. For example, even though inputs of P and nitrogen (N) into the Baltic Sea have significantly decreased over the past two decades, the Baltic Sea still represents a eutrofied body of water. To further reduce P losses from agriculture, current P abatement methods must be amended with additional techniques. One such technique involves the use of P-retaining materials as filters placed in ditches within agricultural areas. This study encompasses a set of laboratory, meso- and large-scale set-ups to identify potential P-retaining materials available in Finland for the treatment of agricultural runoff. The laboratory studies investigated the P retention potential of fresh and weathered Ca-rich (Sachtofer PR®, steel slag, Filtra P®, Filtralite P®) as well as Fe-rich materials (mine drainage residual - MDR) in flow-through tests when applying a high influent P concentration of 50 mg/l. The weathering process served to leach out soluble species such as Ca2+ and OH-, thus mimicking aged filters. In addition, desorption/dissolution tests involved the placement of P-saturated materials in solutions of variable pH as well as one-month extraction with large volumes of water. Sachtofer PR®, steel slag, Filtra P® and MDR retained relatively large amounts of P, varying between 12 and 24 mg P/g material. As desorption/dissolution tests show, two distinct mechanisms controlled the materials retention of P: precipitation of Ca-phosphates and sorption of P onto Fe-hydroxide surfaces. As the most promising material, Sachtofer PR® was further employed in meso- (20 kg) and large-scale (7 tons) filters that treated influents with significantly lower P concentrations, up to 6 mg/l and 0.25 mg/l, respectively. The feed solution in the meso-scale filter alternated between P-enriched tap and river waters, whereas the large filter treated agricultural runoff from 17 ha of cropland. As the application of Sachtofer was scaled up, and influent P concentration declined, cumulative P retention decreased from 19 mg P/g in the laboratory to 0.06 mg P/g in the field. The meso-scale experiment indicated that the P removal efficiency decreased also due to the presence of dissolved organic carbon (DOC) in the influents; the filter retained about 10% of the total amount of DOC added to the system. As for the large filter, the formation of preferential water pathways resulting from material decomposition and freezing-thawing cycles greatly reduced its efficiency. Moreover, in high flow conditions during spring snowmelts or high rainfalls, the large filter treated only a small portion of the incoming flow; the estimated treated flow during the entire test period was about 20%. Maintaining a low effluent limit is rather challenging, and such techniques should instead serve to remove a significant part (e.g., 30-40%) of the dissolved mass of P in agricultural runoff. To justify the potential P recovery from spent filters and to ensure cost-efficiency, the P-retaining material should reach a significant P saturation. In addition, P removal structures should be coupled with other best management practices to minimize losses of P from agriculture. Keywords: P-retaining materials, P retention, precipitation, sorption, upscaled application, dissolved organic carbon, material alteration, preferential flows, high flows, filters, permeable reactive barriers
  • Jokela, Venla (Helsingin yliopisto, 2015)
    Timothy (Phleum pratense L.) is one of the most important forage grass species grown at high latitudes. Its sward canopy structure determines the quantity and quality of the silage yield. Nonetheless, processes behind the transition to flowering, as well as the formation of stems and the connection with forage quality have not been studied in detail for timothy. Seven experiments were conducted to explore the effect of vernalization, photoperiod and gibberellin treatments on flowering and canopy structure in different cultivars or accessions. In addition, the expression of key regulator genes, VRN1 and VRN3, as well as the flowering repressors VRN2 and MADS10 were studied, and the connection between these and flowering induction and stem formation was revealed. Results showed that photoperiod is the most important regulator of flowering in timothy. In addition, vernalization response was reported in most of the tested accessions, which was seen as faster flowering. It was found that the application of GA3 could not replace the LD requirement for flowering. Moreover, results showed that the requirement for flowering and stem elongation vary. Flowering is also associated with decreased digestibility of grass stems. Our results showed, however, that flowering induction was not required for the development of the lignified sclerenchyma ring in developing stems, but rather lignin accumulation was as a result of stem elongation and requirements for mechanical support. At molecular level, novel vernalization-related partial cDNAs were identified through sequencing. Both PpVRN1 and PpVRN3 homologs induced the transition to reproductive development, but PpVRN3 was required for flowering. These results support the theory of universal flowering-promoting system between species. The expression of the putative repressor homolog, PpMADS10, was connected to the developmental stage of the apex. Results obtained in this thesis shed new light on the regulation of flowering and canopy structure in timothy. It is concluded that large variation exists among accessions in their responses to vernalization and photoperiod. This information can be utilized in breeding for high-yielding new cultivars for different growing conditions at high latitudes and for different harvesting strategies.
  • Epie, Kenedy Etone (Helsingin yliopisto, 2015)
    The increasing use of fossil fuel is plagued with problems leading to interest in alternative sources of energies. Bioenergy or biomass energy remains today s important renewable energy source that can contribute to reducing the overall consumption of fossil fuel and can move energy systems towards sustainability and supply security. However, doubts on sustainability impede the acceptance of bioenergy. Hence, the sustainable cropping of reed canary grass (Phalaris arundinacea L., RCG), an established perennial energy grass, was studied. Important sustainability criteria were considered, namely; land use, biomass productivity, emission of greenhouse gas nitrous oxide (N2O) and biodiversity. The general aim of the study was to develop farming methods that would provide biomass feedstock of RCG in a sustainable manner. Field and glasshouse experiments were carried out at the University of Helsinki, Finland, during 2008 to 2013. The suitability of problematic acid sulphate soils managed with raised water tables for cropping RCG was investigated in lysimeter experiments. Growth parameters were measured and biomass yield and energy qualities were determined. In field conditions with soils classified as Gleyic Stagnosol, RCG was supplied with N from inorganic fertilizer and N fixed into soil by intercropped legume galega (Galega orientalis Lam.) and its biomass yields and mineral element composition and other energy qualities were determined. Gases were collected from these fields using closed chambers and greenhouse gas N2O emissions were analysed by gas chromatography. The crop and crop mixture effects on earthworm communities were determined by the extraction of earthworms using mustard oil and manual separation from soil. Reed canary grass grew well in acid sulphate soils and even performed better by producing more biomass with better quality when the water table was raised to reduce acidity and to avoid environmental hazards. Carbon was also sequestered into the soil by RCG root biomass. In the field experiment, RCG galega mixtures produced equally good biomass yields and of better energy quality than the fertilized RCG counterpart. The annual cumulative emissions of N2O from mixtures were marginally lower than those from fertilized RCG soils. Although fertilized RCG produced twice as much biomass and correspondingly higher nitrogen and energy yields, its low emission of N2O per ton of dry matter or per unit of harvestable bioenergy was not significantly different from that of the mixtures. Mixtures also enhanced earthworm abundance and species numbers compared to pure RCG stands. Therefore cropping an RCG galega mixture for biofuel may supply a good quantity of biomass feedstock, result in lower N2O gas fluxes, and sustain earthworm biodiversity but requires management to maintain grass as the major component. Using managed acid sulphate soils for perennial energy cropping will help to reduce the tension between food and energy crop production over arable land and may improve the negative perception of bioenergy as a whole. A 25% Galega- 75% RCG mix has the potential to replace N fertilizer input during energy crop cultivation, meaning reduced cost of production and more income for energy crop farmers. Moreover soil macrofauna diversity will be conserved. With reduced N2O gas emission, this grass-legume mixture could make a significant contribution in mitigating climate change and its effects. All these will come a long way to help in making bioenergy more sustainable.