Browsing by Subject "Fungi"

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  • Kallio, Tauno (Suomen metsätieteellinen seura, 1971)
  • Helfenstein, Andreas; Vahermo, Mikko Martti Antero; Nawrot, Dorota Anna; Demirci, Fatih; İşcan, Gökalp; Krogerus, Sara; Yli-Kauhaluoma, Jari Tapani; Moreira, Vânia M.; Tammela, Päivi Sirpa Marjaana (2017)
    Abietic and dehydroabietic acid are interesting diterpenes with a highly diverse repertoire of associated bioactivities. They have, among others, shown antibacterial and antifungal activity, potentially valuable in the struggle against the increasing antimicrobial resistance and imminent antibiotic shortage. In this paper, we describe the synthesis of a set of 9 abietic and dehydroabietic acid derivatives containing amino acid side chains and their in vitro antimicrobial profiling against a panel of human pathogenic microbial strains. Furthermore, their in vitro cytotoxicity against mammalian cells was evaluated. The experimental results showed that the most promising compound was 10 [methyl N-(abiet-8,11, 13-trien-18-yl)-D-serinate], with an MIC90 of 60 mu g/mL against Staphylococcus aureus ATCC 25923, and 8 mu g/mL against methicillin-resistant S. aureus, Staphylococcus epidermidis and Streptococcus mitis. The IC50 value for compound 10 against Balb/c 3T3 cells was 45 mu g/mL. (C) 2016 Elsevier Ltd. All rights reserved.
  • Kurimo, Rane (Helsingin yliopisto, 2021)
    Sienet ovat harvinaisia nenän sivuontelotulehdusten aiheuttajia. Useimmiten sienisinuiitin aiheuttajana on Aspergillus-suvun sienilaji. Tämän tutkielman tavoitteena on selvittää aspergillus-sienisinuiittiin sairastuneiden potilaiden taustoja ja mahdollisia sienisinuiiteille altistavia tekijöitä. Tämän lisäksi tutkitaan, onko eri riskiryhmien välillä eroja taudista parantumisessa. Tutkimusta varten on kerätty vuosilta 2007–2018 kaikki HUS:n Helsingin Korva-, nenä- ja kurkkutautien klinikassa hoidetut potilaat, joilta otetuissa nenän sivuonteloiden sieniviljelynäytteissä on kasvanut Aspergillus-suvun sienilaji. Aineisto koostuu 86 potilaasta, joilta kerättiin tiedot aiemmista sairauksista, lääkityksestä, nenän alueen leikkauksista ja tupakoinnista. Tiedot kerättiin HUS:n alueella käytössä olleista potilastietojärjestelmistä Uranuksesta ja Navitaksesta sekä Kanta-arkistosta. Suurimmalla osalla oli todettavissa vähintään yksi todennäköisesti sieni-infektiolle altistanut riskitekijä. Vain muutamalla ei tullut esiin selkeää altistavaa tekijää. Kolmella potilaalla todettiin invasiivinen tautimuoto. Aineistossa nousi esiin samoja altistavia tekijöitä sienisinuiiteille, kuin mitä muissakin vastaavissa tutkimuksissa on havaittu, merkittävimpänä hematologiset syövät sekä pitkäaikaiset tai voimakkaat immunosuppressiiviset lääkitykset. Uutena löydöksenä havaittiin astmaa sairastavilla taudin kehittyvän todennäköisemmin useamman sinuksen taudiksi. Usean sinuksen tautiin sairastuneet olivat myös selvästi nuorempia kuin yhden sinuksen tautia sairastavat.
  • Lilja, Petrus (Helsingin yliopisto, 2021)
    Sienisinuiitit ovat nenän sivuonteloiden tulehduksia, joissa taudinaiheuttajana on sieni. Niiden taudinkuva vaihtelee tavanomaisen sinuiitin kaltaisista erittäin vakaviin, joskus nopeastikin eteneviin invasiivisiin muotoihin. Sienisinuiittien diagnosointiin liittyy useita haasteita. Erityisesti vakavissa sienisinuiittimuodoissa voi diagnoosin ja hoidon aloituksen viivästyminen heikentää potilaan ennustetta. Tämän tutkielman tavoitteena on selvittää, saattaisiko joillain bakteereilla olla yhteys sienten esiintymiseen sinuiiteissa. Tällöin näiden bakteerien kohdalla voisi jo lähtökohtaisesti osata herkemmin epäillä sienisinuiitin mahdollisuutta, mikä voisi jouduttaa sienisinuiittidiagnoosiin pääsemistä ja asianmukaisen hoidon aloittamista. Tutkimuksen aineistona on 142 potilasta, joiden sivuontelonäytteiden laboratoriovastauksissa on yhtenä löydöksenä ollut sieni. Taulukoihin kootuista vastauksista selvitettiin sieni- ja bakteerilöydökset ja niiden jakautuminen potilaan mediaani-iän mukaan. Lisäksi koottiin vertailua varten yhteen yleisimmät sienilöydökset ja niiden kanssa esiintyneet bakteerit. Sienilöydöksistä suurin osa oli määritelty jonkinlaisiksi rihmasieniksi. Tarkemmin määritellyistä sienistä valtaosa oli aspergilluksia (nuijahomeita). Vastauksia tarkasteltaessa osoittautui natiivitutkimus sieniviljelyä selvästi herkemmäksi sienen havaitsemisessa. Aineiston bakteerilöydökset osoittautuivat enimmäkseen sekakasvuksi. Yleisimpiä bakteerilöydöksiä olivat stafylokokit (erityisesti Staphylococcus aureus), streptokokit ja hemofilukset (erityisesti Haemophilus influenzae) sekä sekalaiset enterobakteerit ja anaerobiset bakteerit. Tämän tutkielman aineiston perusteella ei löytynyt sellaisia bakteereita, jotka yksiselitteisesti viittaisivat sienisinuiitin mahdollisuuteen. Yleisimmät bakteerilöydökset olivat samoja, joita löytyy muistakin sinuiittimuodoista ja myös terveistä sivuonteloista. Tietyt bakteerit, kuten hemofilukset, saattavat kuitenkin olla yleisempiä sienisinuiittien yhteydessä. Aiempaa tutkimusta aiheesta on vähän, ja tämän tutkielman aineistolla tällaista vertailua ei voi luotettavasti tehdä.
  • Pakarinen, Aku; Fritze, Hannu; Timonen, Sari; Kivijarvi, Pirjo; Velmala, Sannakajsa (2021)
    Arbuscular mycorrhizal fungi (AMF) enhance plant phosphorus uptake, increase soil water holding abilities, reduce soil erosion and can protect their hosts from soil-borne pathogens. Hence, AMF play an important part in improving sustainable agricultural practices, and information about the effects of different preceding crop species on the following crop's AMF well-being is crucial for designing crop rotations. We studied onion root and soil microbial diversity and onion root AMF colonization rates after being preceded by three AMF hosting and one non-hosting green manure crop species in a boreal climate organic field. One-season cultivation of different preceding green manure crops did not have a strong effect on AMF colonization or microbial diversity in onion roots nor in the surrounding soil. Onions had high AMF colonization and microbial diversity after all four preceding crops. The overall fungal and bacterial populations of the soil reacted more strongly to seasonal variations than preceding crops. The study suggests that one season is a too short time to influence the AMF community in boreal climate organic fields with conventional tillage. Thus, non-host preceding crops can also be used in rotations, especially together with AMF host crops.
  • Kovalchuk, Andriy; Kohler, Annegret; Martin, Francis; Asiegbu, Fred O. (2015)
    Background: Transporter proteins are predicted to have an important role in the mycorrhizal symbiosis, due to the fact that this type of an interaction between plants and fungi requires a continuous nutrient and signalling exchange. ABC transporters are one of the large groups of transporter proteins found both in plants and in fungi. The crucial role of plant ABC transporters in the formation of the mycorrhizal symbiosis has been demonstrated recently. Some of the fungal ABC transporter-encoding genes are also induced during the mycorrhiza formation. However, no experimental evidences of the direct involvement of fungal ABC transporters in this process are available so far. To facilitate the identification of fungal ABC proteins with a potential role in the establishment of the mycorrhizal symbiosis, we have performed an inventory of the ABC protein-encoding genes in the genomes of 25 species of mycorrhiza-forming fungi. Results: We have identified, manually annotated and curated more than 1300 gene models of putative ABC protein-encoding genes. Out of those, more than 1000 models are predicted to encode functional proteins, whereas about 300 models represent gene fragments or putative pseudogenes. We have also performed the phylogenetic analysis of the identified sequences. The sets of ABC proteins in the mycorrhiza-forming species were compared to the related saprotrophic or plant-pathogenic fungal species. Our results demonstrate the high diversity of ABC genes in the genomes of mycorrhiza-forming fungi. Via comparison of transcriptomics data from different species, we have identified candidate groups of ABC transporters that might have a role in the process of the mycorrhiza formation. Conclusions: Results of our inventory will facilitate the identification of fungal transporters with a role in the mycorrhiza formation. We also provide the first data on ABC protein-coding genes for the phylum Glomeromycota and for orders Pezizales, Atheliales, Cantharellales and Sebacinales, contributing to the better knowledge of the diversity of this protein family within the fungal kingdom.
  • Beimforde, Christina; Feldberg, Kathrin; Nylinder, Stephan; Rikkinen, Jouko; Tuovila, Hanna; Doerfelt, Heinrich; Gube, Matthias; Jackson, Daniel J.; Reitner, Joachim; Seyfullah, Leyla J.; Schmidt, Alexander R. (2014)
  • Dilokpimol, Adiphol; Mäkelä, Miia Riitta; Varriale, Simona; Zhou, Miaomiao; Cerullo, Gabriella; Gidijala, Loknath; Hinkka, Harri Tapio; Brás, Joana L.A.; Jütten, Peter; Piechot, Alexander; Verhaert, Raymond; Hilden, Sari Kristiina; Faraco, Vincenza; de Vries, Ronald (2018)
    Feruloyl esterases (FAEs) are a diverse group of enzymes that specifically catalyze the hydrolysis of ester bonds between a hydroxycinnamic (e.g. ferulic) acid and plant poly- or oligosaccharides. FAEs as auxiliary enzymes significantly assist xylanolytic and pectinolytic enzymes in gaining access to their site of action during biomass saccharification for biofuel and biochemical production. A limited number of FAEs have been functionally characterized compared to over 1000 putative fungal FAEs that were recently predicted by similarity-based genome mining, which divided phylogenetically into different subfamilies (SFs). In this study, 27 putative and six characterized FAEs from both ascomycete and basidiomycete fungi were selected and heterologously expressed in Pichia pastoris and the recombinant proteins biochemically characterized to validate the previous genome mining and phylogenetical grouping and to expand the information on activity of fungal FAEs. As a result, 20 enzymes were shown to possess FAE activity, being active towards pNP-ferulate and/or methyl hydroxycinnamate substrates, and covering 11 subfamilies. Most of the new FAEs showed activities comparable to those of previously characterized fungal FAEs.
  • Dilokpimol, Adiphol; Makela, Miia R.; Cerullo, Gabriella; Zhou, Miaomiao; Varriale, Simona; Gidijala, Loknath; Bras, Joana L. A.; Jutten, Peter; Piechot, Alexander; Verhaert, Raymond; Faraco, Vincenza; Hilden, Kristiina S.; de Vries, Ronald P. (2018)
    4-O-Methyl-D-glucuronic acid (MeGlcA) is a side-residue of glucuronoarabinoxylan and can form ester linkages to lignin, contributing significantly to the strength and rigidity of the plant cell wall. Glucuronoyl esterases (4-O-methyl-glucuronoyl methylesterases, GEs) can cleave this ester bond, and therefore may play a significant role as auxiliary enzymes in biomass saccharification for the production of biofuels and biochemicals. GEs belong to a relatively new family of carbohydrate esterases (CE15) in the CAZy database (www.cazy.org), and so far around ten fungal GEs have been characterized. To explore additional GE enzymes, we used a genome mining strategy. BLAST analysis with characterized GEs against approximately 250 publicly accessible fungal genomes identified more than 150 putative fungal GEs, which were classified into eight phylogenetic sub-groups. To validate the genome mining strategy, 21 selected GEs from both ascomycete and basidiomycete fungi were heterologously produced in Pichia pastoris. Of these enzymes, 18 were active against benzyl D-glucuronate demonstrating the suitability of our genome mining strategy for enzyme discovery.
  • Marttinen, Eeva M.; Niemi-Kapee, Juhamatti; Laaka-Lindberg, Sanna; Valkonen, Jari P. T. (2020)
    Green roofs play an important role for cities in mediating some problems caused by urbanization. Mosses are ecologically important plants and capable of tolerating harsh conditions, and thus their use for greening building surfaces has become more common. There is only a little information concerning moss-associated microbes, especially those found in green roof environments. Moss-associated microbes might have significant role on the welfare of green roofs as they might induce both beneficial as well as adverse effects on mosses. In this study, the occurrence of fungal populations was studied on green roofs in Finland. A total of 94 samples were collected from nine different green roofs, and 64 fungal isolates and one oomycete were obtained from the brown, necrotic parts of the collected green roof mosses. The most general isolated fungal genus was Trichoderma, comprising 25 different fungal isolates. The second most common genus was Fusarium, with 15 fungal isolates. The third most common genus was Mucor, with nine fungal isolates. Most of the Trichoderma isolates were described as T. harzianum, whereas most of the Fusarium isolates were described as F. acuminatium. In addition, the genera Phoma and Mortierella were frequently present. Fifty-two of 65 isolates caused symptoms in the model plant Physcomitrella patens. The most harmful Trichoderma isolates were described as T. atroviride, T. viride, T. koningiopsis and T. hamatum, all of which caused severe damage to the protonema, stem and leaves. The most harmful Fusarium isolates were F. acuminatium, F. avenaceum and F. tricinctum. The genera Mucor and Mortierella were isolated but they did not cause detectable symptoms in P. patens. These results indicate that many fungal isolates belonging to different genera are able to colonize mosses on green roofs and some of them cause severe damage to the mosses.
  • Turzhanova, Ainur; Khapilina, Oxana; Tumenbayeva, A; Shevtsov, Vladislav; Raiser, Olesya; Kalendar, Ruslan (2020)
    The genus Alternaria is a widely distributed major plant pathogen that can act as a saprophyte in plant debris. Fungi of this genus frequently infect cereal crops and cause such diseases as black point and wheat leaf blight, which decrease the yield and quality of cereal products. A total of 25 Alternaria sp. isolates were collected from germ grains of various wheat cultivars from different geographic regions in Kazakhstan. We investigated the genetic relationships of the main Alternaria species related to black point disease of wheat in Kazakhstan, using the inter-primer binding site (iPBS) DNA profiling technique. We used 25 retrotransposon-based iPBS primers to identify the differences among and within Alternaria species populations, and analyzed the variation using clustering (UPGMA) and statistical approaches (AMOVA). Isolates of Alternaria species clustered into two main genetic groups, with species of A.alternata and A.tennuissima forming one cluster, and isolates of A. infectoria forming another. The genetic diversity found using retrotransposon profiles was strongly correlated with geographic data. Overall, the iPBS fingerprinting technique is highly informative and useful for the evaluation of genetic diversity and relationships of Alternaria species.
  • Kahkonen, Mika A.; Miettinen, Otto; Hilden, Kristiina S. (2020)
    The impacts of Ho and Li (0, 10, 50, 200 mg/L) were tested towards the growth of four basidiomycetous fungal species, their ability to decolorise synthetic dyes (Reactive Green 19, Reactive Orange 16, Reactive Black 5), and produce oxidative enzymes. All species;Agrocybe dura,Skeletocutis biguttulata,Exidia saccharinaandGalerina paludosa;grew with and without supplemented Ho or Li. The growth ofS. biguttulatawas the most tolerant species towards Ho or Li (200 mg/L), whereas the growth ofG. paludosawas the most sensitive of the studied species to both 200 mg Ho or Li/L. All fungi oxidized ABTS [2,2 '-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid)] forming colour zone on plate tests indicating production of lignin modifying laccase enzyme.A. duraandG. paludosa,formed black MnO(2)zone in Mn(2+)plates, which indicates the production of manganese peroxidase (MnP).A. duraandG. paludosadecolorised Reactive Black 5 indicating the production of versatile peroxide (VP) enzyme. Our study presents two new candidate species able to produce VP.A. durawas capable of decolorising all tested synthetic dyes in the presence of Ho or Li (0-200 mg/L) suggesting that this fungus is a promising species for bioremediation of multi dye-containing wastes.
  • Silfver, Tarja; Kontro, Merja; Paaso, Ulla; Karvinen, Heini; Keski-Saari, Sarita; Keinanen, Markku; Rousi, Matti; Mikola, Juha (2018)
    Background and aims Differences among plant genotypes can influence ecosystem functioning such as the rate of litter decomposition. Little is known, however, of the strength of genotypic links between litter quality, microbial abundance and litter decomposition within plant populations, or the likelihood that these processes are driven by natural selection. Methods We used 19 Betula pendula genotypes randomly selected from a local population in south-eastern Finland to establish a long-term, 35-month litter decomposition trial on forest ground. We analysed the effect of litter quality (N, phenolics and triterpenoids) of senescent leaves and decomposed litter on microbial abundance and litter mass loss. Results We found that while litter quality and mass loss both had significant genotypic variation, the genotypic variation among silver birch trees in the quantity of bacterial and fungal DNA was marginal. In addition, although the quantity of bacterial DNA at individual tree level was negatively associated with most secondary metabolites of litter and positively with litter N, litter chemistry was not genotypically linked to litter mass loss. Conclusions Contrary to our expectations, these results suggest that natural selection may have limited influence on overall microbial DNA and litter decomposition rate in B. pendula populations by reworking the genetically controlled foliage chemistry of these populations.
  • Lusa, Merja; Knuutinen, Jenna; Lindgren, Marcus; Virkanen, Juhani; Bomberg, Malin (2019)
    The bacterial, fungal and archaeal communities were characterized in 17 top soil organic and mineral layer samples and in top sediment samples of the Paukkajanvaara area, a former pilot-scale uranium mine, located in Eno, Eastern Finland. using amplicon sequencing and qPCR. Soil and sediment samples were in addition analyzed for (Ra-226), radium sulfate (SO42-), nitrate (NO3-) and phosphate (PO43-) concentrations. New bacterial strains, representing Pseudomonas spp., were isolated from the mine and reference area and used in laboratory experiments on uptake and leaching of radium (Ra). The effect of these strains on the sulfate leaching from the soil samples was also tested in vitro. Between 6 x 10(6) and 5 x 10(8) copies g(-1) DW (dry weight) of bacterial 16S rRNA genes, 5 x 10(5)-1 x 10(8) copies g(-1) DW archaeal 16S rRNA genes and 1 x 10(5)-1 x 10(8) copies g(-1) DW fungal 5.8S rRNA genes were detected in the samples. A total of 814. 54 and 167 bacterial, archaeal and fungal genera. respectively, were identified. Proteobacteria, Euryarchaeota and Mortiriella were the dominant bacterial, archaeal and fungal phyla, respectively. All tested Pseudomonas spp. strains isolates from Paukkajanvaara removed Ra from the solution, but the amount of removed Ra depended on incubation conditions (temperature, time and nutrient broth). The highest removal of Ra (5320 L/kg DW) was observed by the Pseudomonas sp. strain T5-6-I at 37 degrees C. All Pseudomonas spp. strains decreased the release of Ra from soil with an average of 23% while simultaneously increasing the concentration of SO42- in the solution by 11%. As Pseudomonas spp. were frequent in both the sequence data and the cultures, these bacteria may play an important role in the immobilization of Ra in the Paukkajanvaara mine area. (C) 2019 The Authors. Published by Elsevier B.V.
  • Esterhuizen, Maranda; Behman Sani, Shirin; Wang, Lin; Kim, Young Jun; Pflugmacher, Stephan (2021)
    Untreated pharmaceutical pollution and their possibly toxic metabolites, resulting from overloaded wastewater treatment processes, end up in aquatic environments and are hazardous to the ecosystem homeostasis. Biological wastewater remediation could supplement traditional methods and overcome the release of these biologically active compounds in the environment. Mycoremediation is especially promising due to the unspecific nature of fungi to decompose compounds through exoenzymes and the uptake of compounds as nutrients. In the present study, we improved on the previous advances made using the fungus Mucor hiemalis to remediate one of the most commonly occurring pharmaceuticals, acetaminophen (APAP), at higher concentrations. The limitation of nitrogen, adjustment of pH, and comparison to, as well as co-cultivation with the white-rot fungus Phanerochaete chrysosporium, were tested. Nitrogen limitation did not significantly improve the APAP remediation efficiency of M. hiemalis. Maintaining the pH of the media improved the remediation restraint of 24 h previously observed. The APAP remediation efficiency of P. chrysosporium was far superior to that of M. hiemalis, and co-cultivation of the two resulted in a decreased remediation efficiency compared to P. chrysosporium in single.
  • Pekkanen, Juha; Hyvärinen, Anne; Sainio, Markku; Erhola, Marina; Haahtela, Tari; Haverinen-Schaughnessy, Ulla; Haukipuro, Kyösti; Jalkanen, Kaisa; Karvala, Kirsi; Lappalainen, Sanna; Reijula, Kari; Rämö, Hannele (2020)
    • Suomessa sisäilmaan liittyvät ongelmat ja oireilu ovat yleisiä, mutta sisäilman keskimääräinen laatu on eurooppalaisittain hyvä. • Oirekeskeisyys ja terveysvaikutuksiin liittyvät ennakkokäsitykset voivat vaikeuttaa sisäilmaongelmien käsittelyä ja potilaiden hoitoa. • Kansallisen sisäilma ja terveys -ohjelman tavoitteena on vähentää sisäympäristön terveys- ja hyvinvointihaittoja. • Ohjelma koostuu neljästä osa-alueesta: tiedolla vaikuttaminen, rakennusten ongelmatilanteet, ihmisten hoito ja tuki sekä koulutus. • Ohjelma onnistuu vain terveydenhuollon ja lääkärikunnan laajan tuen avulla.
  • Remes, Paula (Helsingin yliopisto, 2018)
    Yhteyksiä sisäilman heikon laadun ja terveyshaitan välillä on tutkimuksissa havaittu runsaasti. Kuitenkin objektiivisia rakennusteknisiä havaintoja on varsinkin kouluja koskevassa tutkimuksessa käytetty vasta niukasti. Tutkimuksen tavoitteena oli kartoittaa rakennusten kunnon ja niiden käyttäjien kokeman oireilun yhteyttä 21 helsinkiläisessä peruskoulussa. Rakennusasiantuntijat määrittivät koulurakennusten kunnon arvioiden rakennusteknisinä muuttujina esimerkiksi ilmanvaihtopuutteita, pinnoite- ja kosteusvauriota sekä lämpöolosuhteita. Ala- ja yläkoulun oppilaat sekä alakoululaisten huoltajat vastasivat sisäilmakyselyyn, jossa kartoitettiin lapsen ja nuoren oireilua sekä myös laajemmin terveydentilaa. Oppilaita tutkimuksessa oli 7 470 ja vanhempia 5 673. Alakoululaisten vastausprosentti oli 70 % ja yläkoululaisten 52 %. Vanhemmista 36 % vastasi. Kosteusvaurio tai ilmayhteys kosteusvauriosta oli yhteydessä sekä yläkoululaisten itsensä että alakoululaisten vanhempien lapsillaan raportoimaan hengitystieoireiluun sekä tuki- ja liikuntaelinoireiluun. Puutteellisella ilmanvaihdolla ja lämpöolosuhteilla havaittiin vastaavat yhteydet oiresummiin yläkoululaisten tuki- ja liikuntaelinoireilua lukuunottamatta. Muu kuin homeeksi tunnistettava, esimerkiksi viemärinhaju tai kemikaaliemissiota indikoiva tuoksu oli yhteydessä yläkoululaisten hengitys- ja alahengitystieoireiluun. Alakoululaisten oireilu oli vain niukasti yhteydessä muuttujiin, joskin nuorimmilla vastaajilla oli huomattavia vaikeuksia täyttää sisäilmakyselyä. Yhteyksillä ei havaittu selkeää annos-vaste-suhdetta. Kuitulähteillä tai muilla epäpuhtauksilla ei ollut yhteyksiä oireiluun. Tulokset tukevat aiempia havaintoja kosteusvaurion ja kemikaaliemission terveyshaitoista. Tulokset korostavat hyvän sisäilmaston merkitystä myös kouluissa. Tuki- ja liikuntaelinoireilun osalta tulokset vahvistavat myös kirjallisuudessa todettua lisätutkimuksen tarvetta. Lisäksi rakennusteknisten muuttujien keskinäisiä korrelatiivisia ja kausaalisia suhteita tulisi tutkia lisää.
  • Kosunen, Maiju; Peltoniemi, Krista; Pennanen, Taina; Lyytikäinen-Saarenmaa, Päivi; Adamczyk, Bartosz; Fritze, Hannu; Zhou, Xuan; Starr, Mike (2020)
    Tree-killing forest disturbances such as storms and bark beetle outbreaks can lead to notable changes in the carbon (C) balance and functioning of forest ecosystems. In this study, the effects of a storm in 2010 followed by an outbreak of European spruce bark beetle (Ips typographus L.) on tree, litter and soil C stocks as well as humus layer C fractions and microbial community composition were examined in boreal Norway spruce (Picea abies L.) stands. Tree (aboveground), litter detritus (distinguishable twig, bark and cones) and soil (humus layer and 0-6 cm mineral soil) C stocks were quantified for undisturbed (living trees), storm disturbed (in 2010) and I. typographus disturbed (tree mortality in circa 2013-2014) plots in 2015-2016. Additional humus layer samples were collected in 2017 for determination of total microbial biomass C, ergosterol (fungal biomass indicator) and K2SO4 extractable (labile) C concentrations, as well as fungal and bacterial community composition (DNA sequencing). Ectomycorrhizal (ECM) fungal mycelial growth in topsoil was also quantified. In spite of the differing initial development and intensity of the two disturbance types, there was little difference in humus layer C and microbiology between the storm and bark beetle disturbed plot types at the time of the study. This may be due to the longer time since the disturbance at the storm disturbed plots. The shift from tree biomass to necromass C stocks was not reflected in differences in SOC stocks or humus layer extractable C concentrations between undisturbed and disturbed plot types, but the amount of litter detritus on forest floor was similar (storm) or higher (beetle) in disturbed plots in comparison to undisturbed ones. Humus layer microbial biomass C and ergosterol concentrations and ECM fungal abundance were lower on disturbed plots in comparison to undisturbed plots. The disturbed plots were also indicated to have a slightly higher abundance of some saprotrophic fungi. Differences in the effects of the two disturbance types may occur when studied at differing spatial scales and at different times after disturbance. To understand the full impact of such disturbances on forest functioning and C balance, long-term monitoring studies will be required.
  • Ukkola, Tarja (University of Helsinki, 1995)