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Faculty of Agriculture and Forestry

 

Recent Submissions

  • Hanski, Kirsi (2021)
    Antibiotic resistance is a growing threat to global health due to overuse and misuse of antibiotics leading to untreatable or difficult to treat infections. Natural environments are an important reservoir of antibiotic resistance. The release of antibiotics into the environment promotes the development of antibiotic resistant bacteria and environmental occurrence of antibiotic resistance genes (ARGs). ARGs are common in nature and prevalent in aquatic environments such as surface waters and effluent. Cyanobacteria are widely found in marine, freshwater, and terrestrial environments. Since their ubiquitous presence in water environments cyanobacteria are exposed to antibiotic pollution and are in contact with resistant bacteria. The role of cyanobacteria in the antimicrobial resistome and dissemination of ARGs has only been studied recently. This work aimed to evaluate the antibiotic susceptibilities of 51 cyanobacterial strains against different classes of antibiotics, using liquid batch cultures, antibiotic discs, and bioinformatics approaches. Cyanobacterial strains used in this work were sensitive to most of the tested antibiotics. However, majority of the strains also showed resistance against trimethoprim and novobiocin. Overall, there was little variation in the antibiotic resistances observed between strains but differences in sensitivity to different antibiotics was observed between species and strains with most differences seen with Nostoc spp. According to bioinformatic tools used (CARD database and BLASTp) FosA protein was found only in strains showing resistance against fosfomycin but not in any sensitive phenotypes and therefore fosA gene was selected as the most promising putative resistance gene for subsequent assays. To determine whether the fosA from cyanobacteria could confer resistance to fosfomycin, the fosA gene from Nostoc sp. XPORK 5A was cloned into pET28a(+) expression vector under the control of T7 promoter and subsequently native cyanobacterial promoter. The ability of Escherichia coli BL21 (DE3) carrying each plasmid constructs to grow in the presence of fosfomycin was determined with agar plates and growth curve assay. E. coli transformants containing the fosA gene and T7 promoter conferred high-level resistance to fosfomycin showing ability to grow at the highest concentrations tested (1mg/ml) on agar plates and (500 µg/ml) in growth curve assay. FosA protein expression from the native cyanobacterial promoter appeared to be weaker and conferred lower-level resistance to fosfomycin (≥ 10 µg/ml). The results of this study provide more information about the antibiotic susceptibility of cyanobacteria. In addition, replicating a horizontal transfer of the fosA gene from cyanobacteria to proteobacteria conferred resistance to fosfomycin and these results may indicate that also nonpathogenic cyanobacteria could act as a source of fosA antibiotic resistance genes.
  • Lindroos, Robin (2021)
    Tämän työn tarkoituksena oli selvittää, onko mahdollista avoimia paikkatieto- ja kaukokartoitusaineistoja hyödyntäen luoda kasvupaikkatyyppiä ennustava malli, jonka ennuste olisi tarkempi kuin saatavilla oleva, koko Suomen kattava Luonnonvarakeskuksen tekemä kasvupaikkamalli. Viime vuosikymmenen aikana avointen paikkatietoaineistojen saata-vuus on lisääntynyt moninkertaisesti. Taustalla on EU:n säätämä INSPIRE-direktiivi 2007/2/EC (EU 2007), jonka tavoit-teena on yhteiskäyttöiset paikkatiedot ja yhteinen paikkatietoinfra-struktuuri. Tässä työssä hyödynnetään useita paikka-tieto- ja kaukokartoitusaineistoja, jotka ovat tulleet avoimeen käyttöön maksutta INSPIRE-direktiivin ansiosta. Aineistojen pohjalta on tunnistettu viisitoista mahdollista muuttujaa, jotka voisivat selittää kasvupaikkatyyppiä. Kaksitois-ta muuttujaa kuvaa topografiaa ja pohjautuvat suoraan tai välillisesti korkeusmalliin, yksi muuttuja kuvaa kasvukauden kokonaissadantaa, yksi muuttuja kuvaa maaperää ja yksi muuttuja on valtapituuden kasvuun pohjautuva kasvupaikka-tyyppiennuste. Valtapituuden kasvuun pohjautuvalle kasvupaikkatyyppiennusteelle kehitettiin malli, joka perustuu mänty-, kuusi- ja koivumetsiköiden kasvatusmalleihin. Näiden muuttujien pohjalta sovitettiin regressioanalyysiä hyödyntäen kasvupaikkatyyppiä ennustavia malleja. Referenssiaineistona käytettiin Suomen metsäkeskuksen kaukokartoituskoealo-ja pohjoisen napapiirin eteläpuolelta. Koealoihin on merkitty kasvupaikkatyyppi, johon malli sovitettiin. Tässä työssä kehitetty paras malli ennustaa mittareiden mukaan kasvupaikkatyyppiä tarkemmin kuin Luonnonvarakes-kuksen kasvupaikkamalli. Paras malli käyttää selittäjinä valtapituuden muutokseen perustuvaa kasvupaikkatyyppiennus-tetta, maalajia, korkeutta merenpinnasta, topografista sijainti-indeksiä (TPI), ”cartographic depth-to-water” -indeksiä (DTW) sekä kasvukauden kokonaissadantaa. Toiseksi paras malli ei hyödynnä maalajia selittäjänä, sillä Geologian tutkimuskeskuksen tuottama maaperäkartta ei kata koko Suomea. Malli käyttää selittäjinä valtapituuden muutokseen pe-rustuvaa kasvupaikkatyyppiennustetta, maalajia, korkeutta merenpinnasta, topografista sijainti-indeksiä (TPI), ”carto-graphic depth-to-water” -indeksiä (DTW), topografista kosteusindeksiä (TWI), kasvukauden kokonaissadantaa sekä auringon potentiaalista kokonaissäteilytystä. Selitysvoimaltaan paras muuttuja perustuu valtapituuden kehityksen tarkasteluun useamman ajankohdan laserkeilausai-neistoja hyödyntäen. Muuttujasta saatavat kasvupaikkatyyppiennusteet ovat sitä tarkemmat, mitä enemmän havaintoja aikasarjassa on. Tämän takia tässä työssä kehitettävän mallin parantamisen ja jatkokehittämisen kannalta olennaista on useamman ajankohdan laserkeilausaineistojen saatavuuden lisääminen. Malli hyödyntää 1970-luvulla kehitettyjä kasva-tusmalleja. On viitteitä siitä, että Suomessa puusto kasvaa nykyään nopeammin kuin 30–40 vuotta sitten. Tulevissa tutki-muksissa tätä kasvun muutosta olisi syytä tutkia tarkemmin ja huomioida se kasvupaikkatyyppiä ennustavien mallien jatkokehittämisessä.
  • Anttila, Tarja (2021)
    Urban forests have recreational values in daily life of people. Planning the use of urban forest is considered through social, ecological, economical and cultural sustainability goals. Besides a forest plan that focuses on concrete forest use, many Finnish municipalities also have a forest strategy. Forest strategy gives a longer perspective for the goals of the use of the forest. Public participation is used as part of the forest planning in municipalities in varying levels. This master’s thesis focuses on the use of different public participation methods in forest planning in Finnish municipalities. The main focus is to explore what kind of methods/ combinations of methods are used and how the municipalities’ forestry experts view the main benefits, problems and chances of improvement in the used practices. The study is carried out as a qualitative study, interviewing forestry experts from 14 Finnish municipalities and analyzing the interviews using qualitative content analysis. The interviews are targeted to municipalities, that have made a forest plan and used public participation in the planning process. The results show that the participatory processes varied a lot between municipalities and each municipality had made their own way of including participatory methods into the forest planning process. However, the methods used were mostly the same, the most used being different kinds of online surveys and surveys using spatial information, common meetings, and forest walks. Two of the municipalities used participatory planning, that involved stakeholders in the planning group. It’s more conventional to use lighter participatory methods, that don’t require as much involvement from the participants. According to the interviews, the main benefits brought by public participation are trust-building, informing residents and having an insight into the public opinion, along with reaching an approved plan. The main problems considering public participation are limited resources and time for the planning, single strong opinions that dominate the conversation, conflicting interests and skills for executing public participation.The ways to improve public participation process included more thorough planning of the process and sufficient amount of time for it, using participatory experts thorugh a consult firm or from municipality’s own workforce, explaining and visualizing effects of forest use for the public and more active ways to inform the public.
  • Ghimire, Sadikshya (2021)
    Fusarium proliferatum has recently become a major threat to onion, which is an important food crop for food security and has a significant role in the agricultural sector. This fungus is found causing rots and producing mycotoxin fumonisin that, if ingested, can cause carcinogenic effects in humans and fatal diseases in animals. F. proliferatum has been identified as a pathogen causing rots and wilts in many plants in several countries, and recently some isolates of this pathogen were also found in Finland causing basal rot in onion. Though F. proliferatum has wide adaptability and pathogenicity, there are research gaps on this newly emerging pathogen, which is mostly limited to some specific hosts such as maize. There is a lack of knowledge of its infection mechanisms and mycotoxin production dynamics in onion. This experimental work was conducted at the University of Helsinki, Finland, to study the nature of pathogenicity and toxin gene expression of F. proliferatum in laboratory conditions as a function of time. Spore suspensions of three isolates of F. proliferatum, Fpr047, Fpr049, and Fpr919, were prepared and used as inoculums that were injected into healthy organically grown onions, which were then stored in dark for five weeks. Control bulbs were inoculated with sterile water. Pathogen virulence, based on symptom development, and fungal colonization in the onion tissues were determined at five different time points and the toxin gene expression was determined at three time points. Colonization levels were determined by real-time PCR using primers binding to the intergenic spacer (IGS) region of F. proliferatum. A part of the IGS region of the three isolates was sequenced to study the diversity between the isolates. All the tested isolates were found to be virulent, and they colonized the onions after one week from inoculation. However, the isolate Fpr919 appeared different from the other two in terms of symptom severity. It was more aggressive than the other two, causing disease symptoms earlier and causing more severe rot symptoms in the infected bulbs. It also had nucleotide sequence variations in the IGS region in comparison with the other two isolates, suggesting genetic diversity. No significant differences were observed between the isolates in the fungal colonization levels. Expression of FUM1 gene and a putative virulence gene SIX2-1 was detected by RT-RT-PCR in most of the infected tissue samples. The results obtained signify that F. proliferatum is a pathogen with the potential of producing fumonisin toxin in onion, suggesting the need for further molecular study on this fungus to control the disease and prevent mycotoxin contamination in plant products.
  • Koskinen, Elisa (2021)
    Cropping conditions are changing also at northern areas due the climate change. Extreme weather conditions demand more buffering capability from the soil and adjusting ability from the plants. Crop rotation and tillage system are in essential role while the change proceeds, as they effect to productivity, pest control and soil health. This study studied the effects of crop rotation on spring barley (Hordeum vulgare L.) yield and pests in two tillage methods, plowing and no-till. This long term (2005-2019) field experiment was arranged in Jokionen, southern Finland. In the experiment, there were two cropping systems: barley monoculture and five years crop rotation (pea – spring wheat – oats – turnip rape/rapeseed – spring barley). Both cropping systems were carried out in ploughed and no-till environment. This study examined the years 2009, 2014 and 2019, when the whole experimental area was on spring barley. In our study, crop rotation did not have considerable effect on barley yield, but tillage method had. Yields were bigger in the ploughed system than in the no-till system. Crop rotation reduced weeds in the plowing system and increased them on no-till. Crop rotation reduced the stem and root rot diseases in spring barley. Tillage method and crop rotation had also effect on leaf blotch severity, especially on scald (Rhynchosporium commune). Only a few insect violations appeared during the examination years, so the effects of crop rotation on occurrence of insects could not be evaluated. Long term crop rotation experiments give valuable information about the strengths and weaknesses of different rotations. Role of the diverse crop rotation will increase further in Finland. More attention needs to be paid to interaction between crops and tillage systems, avoiding soil compaction, focusing to improve soil health and structure so the plants would have good opportunities to use their whole yield potential.