Maatalous- metsätieteellinen tiedekunta


Recent Submissions

  • Chan, Tommy (Helsingin yliopisto, 2016)
    Chan, Tommy 2016. Dynamic variations in bark hydraulics understanding whole tree processes and its linkage to bark hydraulic function and structure. University of Helsinki, Department of Forest Sciences A mature tree stem generally consists of a column of wood that is composed of a series of annual incremental layers and enclosed in a covering of bark. The dynamic variations of the bark are complex due to its structure and function: the thick outer-bark acts as a protective barrier against the abiotic and biotic environment; while the phloem is where sugar transport occurs. Much of the bark variation is due to the transport of sugars and its related processes. The xylem pathway, which transports water in the opposite direction, is connected to the phloem in parallel along the entire length of the stem. The immediate connection between these two transport pathways suggests a functional linkage. The purpose of this thesis is to study the dynamic processes that occur within the bark and its interaction with other internal tree processes and the external environment. These interactions have not been thoroughly quantified, especially on an intra-annual (e.g. daily) scale. The thesis consists of four papers, of which one is a modelling paper and three are experimental studies. Growth is estimated with the model by separating the water-related influences from measured inner-bark, revealing a growth signal proxy for cambial stem growth. Using this signal, a correlation study to microclimate variables is examined in one paper; and to assumed growth respiration in a second paper. The remaining two papers explore the seasonality of photosynthesis and respiration, and bark stem dynamics during the spring recovery period. As a conclusion of this thesis, these papers show how inextricably linked individual tree processes and the environmental are to the changes within the bark. The culmination of this thesis opens new opportunities to further understand the dynamics of bark hydraulics and ecophysiological processes by implementing field measurements and state-of-the-art modelling. Keywords: xylem, phloem, growth, respiration, photosynthesis, spring recovery
  • Chamlagain, Bhawani (Helsingin yliopisto, 2016)
    Vitamin B12 (later B12) intake is insufficient in developing countries, and globally, vegetarians and vegans are also at risk of B12 deficiency. Occurring naturally only in foods of animal origin, new affordable and sustainable dietary sources of B12 are needed to ensure sufficient intake. The only known food-grade producers of active B12, Propionibacterium freudenreichii strains, however, are yet to be exploited to enrich plant-based foods with B12. The B12 production capacity of P. freudenreichii depends on the strain, and the availability of the B12 lower ligand (5,6-dimethylbenzimidazole, DMBI) is a key factor for the production of active B12. Bread can be considered as a potential food for B12 fortification; yet the stability of in situ-produced B12 incorporated during breadmaking processes is not known. Current analytical methods such as the microbiological assay (MBA) lack the required specificity and the existing high-performance liquid chromatography (HPLC) methods are only capable of measuring higher B12 levels in fortified foods and supplements. The determination of active B12 in fermented foods, however, needs sensitive and selective methods. An ultra-HPLC (UHPLC) method was developed and validated to measure the active B12 contents. The identity of the B12 form was confirmed with an ion-trap or quadrupole time-of-flight mass spectrometry (MS). The B12 production capacity of 27 P. freudenreichii and 3 Propionibacterium acidipropionici strains was first studied in whey-based medium (WBM), and three of these P. freudenreichii strains were chosen to study B12 production in three aqueous cereal matrices prepared from malted barley (BM; 33% w/v), barley flour (BF; 6% w/v) and wheat aleurone (AM). Riboflavin (RF) and nicotinamide (NAM) as food-grade replacements for DMBI were investigated in WBM and cereal matrices. The stability of in situ-produced B12 and added cyanocobalamin (CNCbl) and hydroxocobalamin (OHCbl) during straight-dough, sponge-dough and sourdough breadmaking was studied. The developed UHPLC method employing an Acquity high-strength silica (HSS) T3 column showed excellent separation of active B12 from its analogues. A low limit of detection (0.075 ng/inj) enabled the measurement of the B12 levels in cell extracts directly and following immunoaffinity purification in extracts of fermented cereal matrices and B12-fortified baking samples. Analysis with UHPLC MS confirmed the production of active B12 by all 27 P. freudenreichii strains in WBM and 3 P. freudenreichii strains in cereal matrices. P. acidipropionici strains, however, produced an inactive form (pseudovitamin B12), thus making them unsuitable for active B12 fortification in foods. The level of B12 production in WBM varied considerably between the strains (0.45‒3.35 µg/mL), which increased up to 4-fold in 12 of the 27 P. freudenreichii strains following supplementation with RF and NAM. In many of these strains, the B12 yield was higher with RF and NAM co-supplementation than with DMBI. In cereal matrices without supplementation, the produced levels of active B12 (9‒37 ng/g) with P. freudenreichii strains were nutritionally significant. The B12 production increased many-fold, reaching up to 430 ng/g in BM, 39 ng/g in BF and 114 ng/g by adding cobalt (Co) and reached 712 ng/g in BM and 180 ng/g in AM with RF and NAM co-supplementation with Co. The incorporated in situ-produced B12 was retained during straight-dough breadmaking and the loss of 29% during sourdough baking was similar to the losses observed for relatively stable CNCbl. However, the added OHCbl decreased by 21%, 31% and 44% respectively in straight-dough, sponge-dough and sourdough breadmaking. These results showed that B12 produced in situ and incorporated during breadmaking was well retained in the bread prepared by the conventional breadmaking processes. This thesis shows that UHPLC combined with MS allows for the accurate identification and quantitation of low levels of active B12 in fermented food matrices (≥1 ng/g). P. freudenreichii strains could be utilised for in situ production of active B12 in cereal matrices and WBM. The availability of RF and NAM could considerably improve B12 production. The produced levels could easily fulfil the recommended dietary allowance set for B12 (e.g. 2‒2.4 µg/day for adults), and could be well retained in bread in the commonly used breadmaking processes.
  • Tanhuanpää, Topi (Helsingin yliopisto, 2016)
    Urban forests provide various ecosystem services. However, they also require fairly intensive management, which can be supported with up-to-date tree-level data. Until recently, the data have been collected using traditional field measurements. Laser scanning (LS) techniques provide efficient means for acquiring detailed three-dimensional (3D) data from the vegetation. The objective of this dissertation was to develop methods for mapping and monitoring urban forests at tree level. In substudy I, a method (MS-STI) utilizing multiple data sources was developed for extracting tree-level attributes. The method combined airborne laser scanning (ALS), field measurements, and tree locations. The field sample was generalized using the non-parametric nearest neighbor (NN) approach. The relative root mean square error (RMSE) of diameter at breast height (DBH) varied between 18.8 33.8%. The performance of MS-STI was assessed in substudy II by applying it to an existing tree register. 88.8% of the trees were successfully detected, and the relative RMSE of DBH for the most common diameter classes varied between 21.7 24.3%. In substudy III, downed trees were mapped from a recreational forest area by detecting changes in the canopy. 97.7% of the downed trees were detected and the commission error was 10%. Species group, DBH, and volume were estimated for all downed trees using ALS metrics and existing allometric models. For the DBH, the relative RMSE was 20.8% and 34.1% for conifers and deciduous trees respectively. Finally, in substudy IV, a method utilizing terrestrial laser scanning (TLS) and tree basic density was developed for estimating tree-level stem biomass for urban trees. The relative RMSE of the stem biomass estimates varied between 8.4 10.5%. The dissertation demonstrates the applicability of LS data in assessing tree-level attributes for urban forests. The methods developed show potential in providing the planning and management of urban forests with cost-efficient and up-to-date tree-level data.
  • Riikonen, Anu (Helsingin yliopisto, 2016)
    In urban forestry, the assessment and valuation of ecosystem services provided by urban trees are increasingly important both for the rationale of planting new trees and for retaining and managing existing tree populations. To support the field of practical urban forestry, research is needed on the net effects of ecosystem services and costs. The aim of this thesis was to analyse the ecosystem service potential of young street tree plantings. To this end, transplanting recovery, tree growth and carbon and water exchange were studied on two case study streets, one planted with Tilia × vulgaris Hayne and the other with Alnus glutinosa (L.) Gaertn. f. pyramidalis Sakari . The relationships between tree growth, tree and soil water and carbon exchange, environmental variables and tree properties were examined. Transplanting recovery of Tilia trees was delayed due to excess soil water, while Alnus trees recovered within the first few years. Alnus shoot growth responded positively and Tilia negatively to an increase in soil water content. Branch leaf area in relation to branch basal area varied, showing effects of transplanting and subsequent adaptation of the trees to the new growing sites. The studied trees accumulated carbon in their woody biomass during the first decade after transplanting, but the sequestration was small relative to carbon loss from the man-made tree soils. Several additional decades of tree growth were estimated to be needed to attain net carbon sequestration in these street tree plantings if peat originating C and/or renewable C lost from tree soils was counted as C loss. Biomass equations developed in traditional forests predicted total aboveground street tree biomass fairly well, but performed unsatisfactorily in estimating specific aboveground biomass compartments. The biomass distribution and litter production of street trees also require further study to gain insights into the role of tree litter in urban biogeochemical cycles. The annual variation in tree water use of the studied trees was high, but within one year, a Penman-Monteith-based evapotranspiration model with added stomatal conductance and leaf area dynamics description, together with soil water status, explained the variation in tree transpiration quite well. Using a single parameterization over all four years examined did not produce reliable tree water use estimates however. Scaling tree transpiration to different canopy cover percentages implied that especially the columnar Alnus trees could transpire a considerable proportion of annual rainfall with attainable canopy cover, potentially contributing to stormwater management.
  • Nyholm, Outi (Helsingin yliopisto, 2016)
    Diarrheagenic Escherichia coli (DEC) strains cause diarrheal diseases and related sequelae in humans. They are important foodborne pathogens that cause significant public health problems worldwide, especially in developing countries, due to poor hygiene and inadequate health care. DEC can be divided into five pathogroups based on their distinctive virulence factors: Shigatoxigenic E. coli (STEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC) and enteroaggregative E. coli (EAEC). The virulence traits of different DEC pathogroups are responsible for diverse intestinal infection symptoms ranging from mild diarrhea to more severe disease such as hemorrhagic colitis and hemolytic uremic syndrome. STEC is considered to be the most dangerous pathogroup because of the severe disease it may cause. E. coli are able to acquire virulence genes through horizontal gene transfer. This originally established the different pathogroups. However, it can also lead to the emergence of novel hybrid strains that possess a mixture of the pathogroup-specific virulence factors. The aim of this thesis was to study the variety of virulence genes of DEC and hybrids of STEC and other DEC. The occurrence and characteristics of hybrid pathogroups of STEC and other DEC were studied in Finland in human and non-human (animal, food, environmental) STEC strain collections. Burkina Faso in West Africa was observed as a model country for DEC occurrence in the developing world. Raw meats sold at local markets in Burkina Faso were screened for the presence of virulence markers for DEC. STEC strains and hybrid strains in raw meats were subsequently isolated, characterized, and compared with the strains appearing in other countries. Genetic background and the virulence combination of hybrid DEC strains was further investigated using whole genome sequencing (WGS) and comparative genomics. Furthermore, the usefulness of WGS as a novel tool for STEC typing was evaluated. Hybrids of STEC and ETEC pathogroups were found both in Finland and Burkina Faso from two climatically and socioeconomically distant countries. Among Finnish human patients and food production animals, STEC/ETEC hybrids were present. In Burkina Faso, STEC/ETEC hybrids were found in raw meat products. In addition, Burkinabe retail meats were found to be heavily contaminated with STEC and other DEC, reflecting poor food hygiene and the common occurrence of potential human pathogens in Burkina Faso. STEC isolated in Burkina Faso were diverse according to their virulence characteristics and serotypes, with similar being associated with human disease. Genomic comparison of the Finnish and Burkinabe STEC/ETEC hybrid strains indicated several virulence genes and that the strains originate from different phylogenetic lineages among E. coli, suggesting their independent emergence. The study indicated that WGS can be used to replace the phenotype-based and gene-based typing methods in STEC typing. The multiple virulence factors, especially the ability to produce several cytotoxins and to adhere to intestinal epithelial cells, may increase the virulence of hybrid E. coli for humans. This may result in more severe disease in a patient and increased spreading potential. Hybrid E. coli should be considered as emerging pathogens, which may have serious consequences for public health. Hybrids of STEC and other DEC should be taken into account in surveillance, and suitable diagnostic methods for their detection and typing should be developed. By applying modern food protection practices, such as the cold chain and decent meat processing hygiene, the common occurrence of DEC may be decreased in retail meats in Burkina Faso as it has been in Finland and other industrialized countries.
  • Hotti, Hannu (2016)
    Coniine, a piperidine alkaloid, is known from poison hemlock (Conium maculatum L.), twelve Aloe species and Sarracenia flava L. Its biosynthesis is not well understood, although a possible route starts with a polyketide formed by a polyketide synthase (PKS). This study focused on identification and characterization of PKS-genes involved in coniine formation, induction of callus from plants containing hemlock alkaloids and investigation of the possibility to elicitate the alkaloid pathway in cell culture in order to understand coniine biosynthesis. Plant materials involved in different stages of this study were investigated for their alkaloid content using gas chromatography-mass spectrometry. A novel type of PKS, CPKS5, was identified as the starter candidate for the initiation of coniine biosynthesis by catalysing the synthesis of the carbon backbone from one butyryl-CoA and two malonyl-CoA moieties. When elicitated, poison hemlock cell cultures produced furanocoumarins but no piperidine alkaloids. The hemlock alkaloids are wider distributed than previously has been thought among Sarracenia, and Aloe spp. contain a new alkaloid for the genus. These results together pave the way towards possible utilization of hemlock alkaloids.
  • Jokiniemi, Tapani (Helsingin yliopisto, 2016)
    Energy saving objectives have arisen recently in all sectors of life due to the climate change sce-narios and depletion of fossil energy resources. In boreal and northern temperate climate zone countries one of the most energy intensive operations in arable farming is grain preservation, which in most cases means drying. This work focused on examining the energy use and energy saving possibilities in grain drying, and grain preservation in general, from several aspects. The main focus was in Finnish conditions, but the results can be applied also in other areas, when applicable. In addition to the energy aspect, some economic considerations were conducted, since economic profit is the ultimate decision making factor for farmers. The principal method for grain preservation in Finland is hot-air drying. Energy use and energy savings in drying hence constituted the major part of the research work included herein. The aim of the work was to produce information that could be easily utilized in current farming practices. Therefore all the experiments and measurements were conducted in grain recirculat-ing mixed-flow hot-air dryer, which is the most common grain dryer type in Finland. The energy utilization in dryer was first examined and energy losses identified, and three energy saving methods were chosen for closer consideration: 1) controlling the air flow rate and temperature of the drying air (publications I and II), 2) heat insulation of the dryer device (III) and 3) heat recovery from the dryer exhaust air (IV). The aim of the method 1) was to improve the utilization of the supplied heat energy by increasing the humidity of the dryer exhaust air and thus reducing the energy losses via sensible heat in the exhaust air. Method 2) aimed to eliminate the heat losses from the dryer surfaces by the heat insulation. Method 3) focused on recovering the sensible as well as latent heat from the dryer exhaust air with a passive parallel plate heat exchanger. In addition to the energy saving potential in drying, also the possibilities for enhanced use of alternative moist grain preservation methods and their effects on the energy consump-tion in grain preservation were examined (publication V). While drying is practically the only suit-able preservation method for market quality grain in Finnish conditions, moist grain preservation methods could be applied basically for all home-grown grain used for animal feeding, which rep-resents roughly one third of the total annual grain yield in Finland. The examined moist grain preservation methods were airtight preservation, acid preservation of whole grains and grain crimping (ensiling). The energy saving possibilities with these methods, compared to the current situation, were evaluated by theoretical calculations. The results indicated that considerable energy savings could be achieved by the methods examined in publications I to V. The drying process control method produced energy savings of 5 15%, depending on the grain species, compared to conventional drying method. The energy savings achieved by the heat insulation were 16 21% in the examined dryer. Heat recovery method saved on average 18% energy compared to the conventional system, and energy sav-ings up to 40% were suggested for passive heat recovery by the theoretical model developed in the publication IV. Moist grain preservation methods for preserving home-grown feed grain provided energy savings of 50 90% compared to drying. The combined energy saving potential of the examined methods was 20 43% of the total energy consumption in grain preservation at the present situation, when the realizable potential was considered. It was concluded that significant energy saving possibilities exist in current grain preser-vation practices and their utilization could aid to reduce the energy consumption in the agricul-tural sector and thus to achieve the energy saving objectives set by authorities. Energy savings of 5 11% of the total direct energy use in arable the farming sector could be achieved. However, even the relatively large energy savings would have quite a modest effect on the economy of farming with the current energy prices, which indicates that the direct energy inputs are still relatively cheap, compared to other inputs. While energy prices are expected to rise in the long term, energy saving measures will become more viable for the economy of farms in the future, which is the ultimate incentive for more energy efficient production.
  • Huang, Xin (Helsingin yliopisto, 2016)
    Gluten-free foods are defined by their lack of prolamins that trigger coeliac disease. In order for foods derived from Triticeae grains to be considered as gluten-free, the prolamins need to be eliminated. Previously, enzymatic degradation of cereal prolamins has been intensively studied. In the present work, another method is investigated, namely the metal-catalysed oxidation of prolamins. The aim was to modify prolamin peptides and proteins, and to examine the modifications, in order to reduce their immunological activities. The metal-catalysed oxidation was first examined on model peptides, including repetitive sequences of prolamin peptides and a model coeliac-toxic peptide (33-mer), and then tested on C-hordein, a model monomeric barley prolamin, and finally on whole hordein, thus covering the range from peptides to a whole protein. The fragmentation of prolamin peptides and proteins was observed to be a consequence, partly due to proline oxidation. On the other hand, aggregation also occurred, through dityrosine formation, disulfide bridges or carbonyl interactions. The amino acid profile and protein structure affected the oxidation behaviours and resulted in various modifications that were compared after metal-catalysed oxidation treatments. The immunoreactivity of oxidised peptides, C-hordein or whole hordein decreased in R5 antibody-based measurements that are used in gluten-free detection. The present study demonstrated that cereal prolamins can be modified by metal-catalysed oxidation, and their immunoreactivities against R5 antibody were reduced. The information of their oxidative modifications offers a new alternative to be utilised in the elimination of prolamins for gluten-free applications.
  • Kuuskeri, Jaana (Helsingin yliopisto, 2016)
    The wood-decaying white-rot fungi have the profound ability to completely degrade lignocelluloses and all wood components. These fungi and their enzymes have evolved to modify the various lignocellulose feedstocks in nature, and thereby, they are important organisms for bioconversions as well as in fundamental research on fungal biology. The enzymes have many potential applications in biotechnology and industrial purposes including bioenergy production. Evolutionary background of the fungal species and their organelles thus requires deeper understanding to aid in elucidating the relationship of the species to their lifestyles. This PhD study concentrated on the white-rot fungal species Phlebia radiata, Finnish isolate number 79 (FBCC0043). The phylogenetic studies confirmed positioning of P. radiata species in the systematic class Agaricomycetes of Basidiomycota, and in the phlebioid clade of the order Polyporales. The sequenced and annotated mitochondrial genome of P. radiata was discovered to have features that indicate evolutionary pressure and structural diversity in fungal mitogenomes, not being as stable and compact entities than was previously believed. In this study, P. radiata together with species like Phlebia acerina and Phlebia brevispora was demonstrated to form a Phlebia sensu stricto group which consists of efficient producers of lignin-modifying enzymes. The results pinpointed that there is a species-level connection of fungal molecular systematics to the efficiency in the production of wood-decaying enzymes and activities. Norway spruce (Picea abies) is a common tree species in the boreal forests providing an important source of biomass for forest-based industry. Therefore, P. radiata was cultivated on Norway spruce wood under conditions mimicking natural solid-wood colonization, up to six weeks of growth, and the dynamics of fungal enzyme production and gene expression was studied. The lignin-modifying class-II peroxidases (LiPs and various MnPs) were produced, especially in the beginning of fungal growth and colonization of wood, thus indicating the essence of class-II peroxidase as the primary enzymes to function against coniferous wood lignin. Moreover, these extracellular oxidoreductases enhance the accessibility of lignocellulose carbohydrates and thereby, they promote fungal growth in wood. Simultaneously, lytic polysaccharide monooxygenases and several CAZyme glycoside hydrolases attacking cellulose, hemicellulose and pectin were produced, which demonstrates ongoing depolymerization of the polysaccharides to monomers and oligomers. Electron microscopic examination of fungal-colonized wood after six weeks of growth indicated that the decay of wood cell walls was initiated at the tracheid lumen side apparently proceeding towards the middle lamellae. Furthermore, degradation of spruce wood lignin was detected by pyrolysis-GC/MS as decrease in the amount of phenylpropane units with concomitant increase in the number of smaller fragmented products from these lignin units. Thus, the previously observed unique and strong ability of P. radiata to degrade wood lignin and lignin-like aromatic compounds was confirmed. According to the results of this PhD study, P. radiata produces the white-rot type of decay of wood components when growing on Norway spruce. This is due to the efficient ability of the fungus to express and produce a versatile enzyme repertoire for degradation of wood lignocellulose, and in consequence, to generate diverse reactions and bioconversions important for carbon cycling in the forest ecosystems.
  • Adamczyk, Sylwia (Helsingin yliopisto, 2016)
    Cycling of carbon (C) and nutrients plays pivotal role for functioning of every ecosystem. Biogeochemical cycles of carbon and nitrogen (N) are balanced by a network of inter-actions between plants, litter and soil chemistry, microbial communities, enzyme machinery and climate conditions. This thesis focuses on the role of terpenes in C and N transformations in boreal forest soils. Terpenes are abundant plant secondary compounds. The focus was on certain mono-, di-, and triterpenes. Soil incubation experiments revealed that terpenes increased the mineralization of carbon but decreased net nitrogen mineralization and net nitrification. Additionally they increased the amounts of carbon and nitrogen in the microbial biomass through enhancement of bacterial growth; however, they inhibited fungal growth. This study suggests that terpenes can act as a C source for some microbial communities. Moreover, terpenes showed inhibitory potential against enzymes, which are involved in C, N, P, S cycling. The mechanism of inhibition seems to be based at least partially on ability of terpenes to bind enzymes. The field experiment presented the effect of logging residues and wood ash on composition of terpenes and C and N cycling in soil five years after clear-cutting a Norway spruce stand. Logging residue treatment increased the concentrations of certain terpenes in the organic layer. Both, logging residue and wood ash treatments increased net N mineralization and net nitrification. Some changes in terpene concentrations correlated with C and N cycling processes, but the relationship between terpene concentration and C and N cycling processes remained still unclear in the field conditions. In conclusion, terpenes can affect C and N transformations in boreal forest soil. It is probable that terpenes change N cycling retaining more N in organic forms and potentially decrease nitrogen losses from forest ecosystem.
  • Shi, Qiao (Helsingin yliopisto, 2016)
    Many lactic acid bacteria are able to synthesize dextrans from sucrose by dextransucrases. Weissella confusa strains have attracted increasing attention due to their production of texture-modifying dextrans during food fermentation. Potential prebiotic oligosaccharides have also been produced by dextransucrases in the presence of sucrose and acceptor sugars. However, only few W. confusa dextransucrases have been previously studied, and the reactions of Weissella dextransucrases to synthesize oligosaccharides have not been investigated. In this thesis, two W. confusa dextransucrases from efficient dextran-producers were studied, and their products were structurally characterized because this information is essential for a better usability of these enzymes and corresponding bacteria in food and health applications. The biochemical and kinetic properties of one of the W. confusa dextransucrases were studied. Two activity assays were compared to determine the kinetic parameters. A sucrose radioisotope assay gave a KM of 14.7 mM and a Vmax of 8.2 µmol/(mg∙min), whereas a Nelson-Somogyi assay gave values of 13.0 mM and 19.9 µmol/(mg∙min), respectively. The dextrans from the two W. confusa dextransucrases were found by, e.g., NMR analysis to consist of mainly α-(1→6) linkages and 3% α-(1→3) branches, of which some were elongated. A high-performance size-exclusion chromatography analysis of the dextrans revealed high molar masses of 107‒108 g/mol. Weissella dextransucrases were also studied with acceptor sugars for the synthesis of glucooligosaccharides. The most efficient acceptor was maltose, followed by isomaltose, maltotriose, and nigerose, which formed series of glucooligosaccharides by the further elongation of intermediate acceptor products. The products derived from maltose formed two homologous series, with one series being predominant and the other being minor. The major maltose product series were linear isomaltooligosaccharides (IMOs) with reducing-end maltose units, as identified by multistage mass spectrometry (MSn) analysis. The minor maltose series were revealed by an NMR analysis of the isolated minor trisaccharide product to bear a novel branched structure. These products contained an α-(1→2)-linked glucosyl residue on the reducing residue of the linear IMOs. These structures have not been previously obtained by a dextransucrase. They probably formed by the attachment of a single-unit branch to linear IMOs. For the acceptor analogs lactose and cellobiose, their main acceptor products were identified by NMR analysis to be branched trisaccharides, with a glucosyl residue α-(1→2) linked to the acceptor s reducing end. Surprisingly, a side product, isomelezitose (6Fru-α-Glcp-sucrose), was produced when using lactose as an acceptor. The synthesis of this nonreducing trisaccharide by a dextransucrase was reported here for the first time. Linear IMOs with a degree of polymerization ≥3.3 serve as prebiotics for their resistance to digestion. However, industrial IMO production often leads to a high portion of unwanted digestible sugars. The dextransucrase reaction in the presence of the efficient acceptor maltose was demonstrated here as a promising alternative synthesis process to control IMO size distribution by varying the sucrose/maltose ratio. The effects of substrate concentrations (0.15 1 M) and dextransucrase dosage (1 10 U/g sucrose) on the IMO yield and profile were modeled. High sucrose (1 M) and medium maltose (0.5 M) concentrations were found to be optimal for the synthesis of long-chain IMOs, with 366 g/L of total IMOs attained.
  • Grammatikopoulou, Ioanna (Helsingin yliopisto, 2016)
    Agricultural lands are managed or modified ecosystems that interact with the surrounding natural environment so as to supply while also to use a great range of ecosystem services (ES). In addition, agriculture is responsible for disservices that negatively affect natural ecosystems. In Finland, agricultural lands have undergone marked changes affecting a great number of vital ES. Traditional agri-environmental policy has been criticized for being inefficient in ensuring the provision of ES or limiting the disservices, while markets have been unable to reflect the demand for or supply of ES due to the public character of some ES. Market-based mechanisms as well as targeted policy measures may ensure effective and efficient ES provision. This dissertation explores the factors that determine the citizen demand for and landowner supply of ES, and considers examples of market- and target-based measures that may supplement or replace the current form of agri-environmental policy. The first part of the dissertation is focused on the demand for and supply of cultural ES provided by agricultural lands. A choice experiment was applied to evaluate a marketbased scheme, i.e. a Payment for Ecosystem Services (PES) scheme that provides certain landscape attributes in a typical agricultural area. The analysis revealed that the most valued attributes were the renovation of production buildings and the presence of grazing animals. The results demonstrated that citizen preferences were heterogeneous, a fact which may affect the level of transaction costs and the performance of the scheme. Landowners were skeptical towards the scheme, willing to provide ES that did not always match with the demand. They also demanded compensation in excess of their expenses. Nonetheless, cost benefit considerations revealed that the scheme may be feasible, as the aggregated welfare benefits outweigh the anticipated costs. The second part is focused on the supply of water conservation services and the avoidance of water eutrophication disservices. During the data collection, Finnish agrienvironmental policy set equal incentives for water conservation, not accounting for environmental conditions, which are spatially varied. Before suggesting any policy reform and the use of alternative measures such as target-based measures, where farmers are compensated for delivering certain ES, it is imperative to investigate the tendency of landowners to adopt water conservation measures. By combining survey data with GIS data, a binary choice model was employed. The model examined the adoption of special measures for water conservation if the soil quality implies a high leaching risk and if the water quality is already poor. Adoption in areas under risk was weakly supported by the study s estimates. This indicates that environmental awareness, assuming it increases with risk, is not strong enough to motivate adoption. Target-based which are spatially tailored measures can attract adopters in hotspot areas. The latter outcome leads to the last subject, which examines farmers participation in an agri-environmental auction scheme. According to the outcomes of the study, farmers who have previously participated in a pilot auction scheme were more likely to be participants in future auctions. The findings also suggested a strong relationship between attitudes and participation, particularly for attitudes related to specific environmental benefits attached to the auction scheme, novelty and financial features, as well as the complexity of the auction mechanism. The ES and disservices examined in this dissertation, i.e. landscape amenities and water eutrophication, are of priority. Finnish agricultural landscape has experienced severe stresses during the past years while the state of the Baltic Sea is largely affected by the eutrophication issues of water bodies. The empirical research findings enhance current knowledge in planning market- and target-based schemes in the years to come. These schemes are attracting increasing attention for being more effective and, if properly designed, more efficient. For agri-environmental auctions in particular, the findings are novel, since they were derived from the first auction experiment ever implemented in Finland.
  • Koskela, Elli (Helsingin yliopisto, 2016)
    Strawberries (Fragaria sp.) belong to the large family of Rosaceae that includes commercially important crop plants such as apple, pear, peach and roses. The economic impact of these species is huge and breeders around the world are striving to keep up with consumers' demands on novelty produce. At the same time, climate change is having an impact on the onset of flowering especially in species that are grown in temperate climates. As flowering is a prerequisite for yield formation, it is extremely important to gain an insight on how the environmental factors, most importantly photoperiod and temperature, affect the timing of flowering in Rosaceous species. Although studying flowering responses directly in the cultivated species could provide immediate practical applications, it is often not feasible due to e.g. complex genomics of the species, large plant size or long juvenile period. The woodland strawberry (Fragaria vesca) (L.) has arisen as a convenient model plant for strawberries and the entire Rose family. It is a diploid species and therefore has a less complex genome than the cultivated octoploid strawberry. The work described here begun by elucidating the molecular identity of SEASONAL FLOWERING LOCUS (SFL), a locus controlling the switch from seasonal to continuous flowering habit in woodland strawberry. SFL was identified as the woodland strawberry orthologue of TERMINAL FLOWER1 (FvTFL1) based on its location on the strawberry genome and similarity to its Arabidopsis counterpart, TFL1. In woodland strawberry, FvTFL1 was shown to be photoperiodically regulated, and it was demonstrated that the continuous flowering habit is caused by a mutation at FvTFL1. In the following experiments, altered regulation of FvTFL1 was associated with the unique vernalisation requirement in the artic F. vesca accession Alta-1, suggesting a previously uncharacterised function for a TFL1 orthologue. The findings on FvTFL1 were extended to cultivated strawberry. It was demonstrated that F. × ananassa homologue of TFL1 (FaTFL1) also represses flowering, and that differences in the regulation of FaTFL1> were associated with different flowering times in strawberry cultivars. The finding that FaTFL1 is a major determinant in the flowering response of cultivated strawberry provides breeders with a new breeding target; producing cultivars with lowered FaTFL1 expression level could expand the flowering and fruiting season of strawberries. These results clearly demonstrate the feasibility of the model plant approach and also highlight the importance of fundamental research. The knowledge gained on fundamental genetic pathways in model plants can be transferred to crop plants, in which similar genetic studies would be impossible or at least extremely complex, slow and costly to perform
  • Holopainen, Jani (Finnish Society of Forest Science, 2016)
    The forest sector has been able to develop many new bio-based and sustainable products catered to business-to-business markets, but the sector still lacks a breakthrough in new forest products and services targeting consumer markets. This is due to higher prices of forest products compared to competing materials, such as concrete, steel, and plastics, but also due to a lack of new product and service innovations targeting end-consumer markets. To understand the emergence of bioeconomy, also bringing new consumer market opportunities to the forest sector, we need to understand the new business ecosystem. The business ecosystem model is a holistic view of the current institutions capturing stakeholder relations and opportunities brought by various resources and technologies. Better understanding of these concepts can lead to consumer-driven development of forest products and services, and improved competitive advantage. This doctoral dissertation introduces a holistic research and development model for new product and service innovations in the forest sector. This research was motivated by the fact that recent forest sector product introductions have been driven by the technology push, and therefore, this research concentrates on the consumer perspective to build new business models and the development of products and services to meet current consumer trends. Evolving sustainability trends among consumers, where bio-based forest products and services can fulfill consumer demand, are central in this thesis. The doctoral thesis consists of one book chapter and three peer-reviewed articles, each using different methodologies. The subjects and results of the papers are grouped into three themes in the framework of the Consumer-Driven Business Ecosystem Research and Development (CDBERD) model. The model extends the classical technology-push and demand-pull innovation model, to better consider consumer values, enabling resources and dominant logics along with the smooth flow of information during each phase of the research and development process leading towards new consumer-driven solutions.
  • D'Amato, Dalia (Helsingin yliopisto, 2016)
    The concept of ecosystem services, wide-spread in academia and policy making, emphasizes societal and economic dependence on natural systems for, among others, provision of food, fibres and water, regulation of climate and soil, and contribution to spiritual and cultural values. Anthropogenic pressures driven by rapid economic development are, however, causing a disruption in the benefits that humans obtain from ecosystems. Several economic sectors both depend on and impact ecosystem services. There is therefore maturing expectation for the private sector involvement in environmental governance worldwide, as firms are increasingly motivated to pursue sustainability for financial or strategic opportunities. This dissertation is among the first to address the current research void on the interactions between industries and ecosystem services. The topic is analysed in the context of extensive plantation forestry in the emerging economy of China. The main aim of this work is to investigate if and how the ecosystem services narrative can contribute to further develop corporate sustainability agendas and practices. Based on the findings from this work, ecosystem services research can provide insights and tools to pursue a more comprehensive and holistic acknowledgement of and response to interlinked ecological and social issues in corporate sustainability. For instance it can enable the understanding of company impacts and dependencies on ecosystems, and associated business risks and opportunities; deepen the analysis of company stakeholders perspectives and expectations; contribute to the design of sustainability-oriented practices; and enrich corporate disclosure practices. Further operationalisation of the ecosystem services approach into corporate sustainability would require a more systematic assessment and comparison of the relations between relevant business sectors and ecosystems, the analysis of global-local trade-offs, the internalizations of concepts such as ecological limits and ecological resilience, and the elaboration of suitable corporate and industrial response strategies. Keywords: China; Corporate sustainability; Ecosystem services; Forest sector; Plantations.