Browsing by Subject "Bacteria"

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  • Cockell, Charles S.; Harrison, Jesse P.; Stevens, Adam H.; Payler, Samuel J.; Hughes, Scott S.; Nawotniak, Shannon E. Kobs; Brady, Allyson L.; Elphic, R. C.; Haberle, Christopher W.; Sehlke, Alexander; Beaton, Kara H.; Abercromby, Andrew F. J.; Schwendner, Petra; Wadsworth, Jennifer; Landenmark, Hanna; Cane, Rosie; Dickinson, Andrew W.; Nicholson, Natasha; Perera, Liam; Lim, Darlene S. S. (2019)
    A major objective in the exploration of Mars is to test the hypothesis that the planet hosted life. Even in the absence of life, the mapping of habitable and uninhabitable environments is an essential task in developing a complete understanding of the geological and aqueous history of Mars and, as a consequence, understanding what factors caused Earth to take a different trajectory of biological potential. We carried out the aseptic collection of samples and comparison of the bacterial and archaeal communities associated with basaltic fumaroles and rocks of varying weathering states in Hawai'i to test four hypotheses concerning the diversity of life in these environments. Using high-throughput sequencing, we found that all these materials are inhabited by a low-diversity biota. Multivariate analyses of bacterial community data showed a clear separation between sites that have active fumaroles and other sites that comprised relict fumaroles, unaltered, and syn-emplacement basalts. Contrary to our hypothesis that high water flow environments, such as fumaroles with active mineral leaching, would be sites of high biological diversity, alpha diversity was lower in active fumaroles compared to relict or nonfumarolic sites, potentially due to high-temperature constraints on microbial diversity in fumarolic sites. A comparison of these data with communities inhabiting unaltered and weathered basaltic rocks in Idaho suggests that bacterial taxon composition of basaltic materials varies between sites, although the archaeal communities were similar in Hawai'i and Idaho. The taxa present in both sites suggest that most of them obtain organic carbon compounds from the atmosphere and from phototrophs and that some of them, including archaeal taxa, cycle fixed nitrogen. The low diversity shows that, on Earth, extreme basaltic terrains are environments on the edge of sustaining life with implications for the biological potential of similar environments on Mars and their exploration by robots and humans.
  • 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.
  • 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.
  • Skurnik, Mikael; Kiljunen, Saija (2016)
  • 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.
  • Tossavainen, Marika; Katyal, Neha; Silja, Kostia; Valkonen, Kalle; Sharma, Anil K.; Sharma, Suvigya; Ojala, Anne; Romantschuk, Martin (2018)
    Microalgae are a sustainable alternative for production of valuable omega -3 fatty acids (FAs), but high production costs limit commercialization. Utilization of waste as a nutrient source increases the economics of the cultivation process. Additionally, using mixed algal cultures instead of monocultures makes the cultivation process more flexible and can increase biomass and lipid production. Here, the growth and lipid production of microalgae Euglena gracilis, Selenastrum sp. and, Chlorella sorokiniana were studied in mono- and mixed cultures in small and pilot scale experiments in biowaste leachate. In pilot scale, also nutrient reduction and the number of bacteria were analyzed. Biomass production in the most productive mixed cultures was similar, but not higher than in most productive monocultures. The lipid production was highest in the small-scale monoculture of Selenastrum (10.4% DW) and in the pilot scale culture of Selenastrum with E. gracilis (11.1% DW). The content of alpha-linolenic acid (ALA) increased and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) remained stable during the cultivation period in all pilot scale cultures. However, increases in biomass and lipid production toward the end of the cultivation resulted in higher EPA and DHA yields in the well growing monoculture of E. gracilis and in the mixed culture of E. gracilis with Selenastrum. Co-cultivation of E. gracilis and Selenastrum also had a positive influence on nutrient uptake and resistance against bacteria. This type of mixed culture may be a good option for commercialization. However, as shown here, minor changes in cultivation conditions can rapidly result in dominance of a subdominant strain, and thus the stability of strain performance and production of desired FAs needs further investigation.
  • Lammel, Daniel R; Barth, Gabriel; Ovaskainen, Otso; Cruz, Leonardo M; Zanatta, Josileia A; Ryo, Masahiro; de Souza, Emanuel M; Pedrosa, Fábio O (BioMed Central, 2018)
    Abstract Background pH is frequently reported as the main driver for prokaryotic community structure in soils. However, pH changes are also linked to “spillover effects” on other chemical parameters (e.g., availability of Al, Fe, Mn, Zn, and Cu) and plant growth, but these indirect effects on the microbial communities are rarely investigated. Usually, pH also co-varies with some confounding factors, such as land use, soil management (e.g., tillage and chemical inputs), plant cover, and/or edapho-climatic conditions. So, a more comprehensive analysis of the direct and indirect effects of pH brings a better understanding of the mechanisms driving prokaryotic (archaeal and bacterial) community structures. Results We evaluated an agricultural soil pH gradient (from 4 to 6, the typical range for tropical farms), in a liming gradient with confounding factors minimized, investigating relationships between prokaryotic communities (16S rRNA) and physical–chemical parameters (indirect effects). Correlations, hierarchical modeling of species communities (HMSC), and random forest (RF) modeling indicated that both direct and indirect effects of the pH gradient affected the prokaryotic communities. Some OTUs were more affected by the pH changes (e.g., some Actinobacteria), while others were more affected by the indirect pH effects (e.g., some Proteobacteria). HMSC detected a phylogenetic signal related to the effects. Both HMSC and RF indicated that the main indirect effect was the pH changes on the availability of some elements (e.g., Al, Fe, and Cu), and secondarily, effects on plant growth and nutrient cycling also affected the OTUs. Additionally, we found that some of the OTUs that responded to pH also correlated with CO2, CH4, and N2O greenhouse gas fluxes. Conclusions Our results indicate that there are two distinct pH-related mechanisms driving prokaryotic community structures, the direct effect and “spillover effects” of pH (indirect effects). Moreover, the indirect effects are highly relevant for some OTUs and consequently for the community structure; therefore, it is a mechanism that should be further investigated in microbial ecology.
  • Lammel, Daniel R.; Barth, Gabriel; Ovaskainen, Otso; Cruz, Leonardo M.; Zanatta, Josileia A.; Ryo, Masahiro; de Souza, Emanuel M.; Pedrosa, Fabio O. (2018)
    Background: pH is frequently reported as the main driver for prokaryotic community structure in soils. However, pH changes are also linked to "spillover effects" on other chemical parameters (e.g., availability of Al, Fe, Mn, Zn, and Cu) and plant growth, but these indirect effects on the microbial communities are rarely investigated. Usually, pH also co-varies with some confounding factors, such as land use, soil management (e.g., tillage and chemical inputs), plant cover, and/or edapho-climatic conditions. So, a more comprehensive analysis of the direct and indirect effects of pH brings a better understanding of the mechanisms driving prokaryotic (archaeal and bacterial) community structures. Results: We evaluated an agricultural soil pH gradient (from 4 to 6, the typical range for tropical farms), in a liming gradient with confounding factors minimized, investigating relationships between prokaryotic communities (16S rRNA) and physical-chemical parameters (indirect effects). Correlations, hierarchical modeling of species communities (HMSC), and random forest (RF) modeling indicated that both direct and indirect effects of the pH gradient affected the prokaryotic communities. Some OTUs were more affected by the pH changes (e.g., some Actinobacteria), while others were more affected by the indirect pH effects (e.g., some Proteobacteria). HMSC detected a phylogenetic signal related to the effects. Both HMSC and RF indicated that the main indirect effect was the pH changes on the availability of some elements (e.g., Al, Fe, and Cu), and secondarily, effects on plant growth and nutrient cycling also affected the OTUs. Additionally, we found that some of the OTUs that responded to pH also correlated with CO2, CH4, and N2O greenhouse gas fluxes. Conclusions: Our results indicate that there are two distinct pH-related mechanisms driving prokaryotic community structures, the direct effect and "spillover effects" of pH (indirect effects). Moreover, the indirect effects are highly relevant for some OTUs and consequently for the community structure; therefore, it is a mechanism that should be further investigated in microbial ecology.
  • Kärnä, Olli-Matti; Heino, Jani; Laamanen, Tiina; Jyrkänkallio-Mikkola, Jenny; Pajunen, Virpi; Soininen, Janne; Tolonen, Kimmo T.; Tukiainen, Helena; Hjort, Jan (2019)
    Context One approach to maintain the resilience of biotic communities is to protect the variability of abiotic characteristics of Earth's surface, i.e. geodiversity. In terrestrial environments, the relationship between geodiversity and biodiversity is well recognized. In streams, the abiotic properties of upstream catchments influence stream communities, but the relationships between catchment geodiversity and aquatic biodiversity have not been previously tested. Objectives The aim was to compare the effects of local environmental and catchment variables on stream biodiversity. We specifically explored the usefulness of catchment geodiversity in explaining the species richness on stream macroinvertebrate, diatom and bacterial communities. Methods We used 3 geodiversity variables, 2 land use variables and 4 local habitat variables to examine species richness variation across 88 stream sites in western Finland. We used boosted regression trees to explore the effects of geodiversity and other variables on biodiversity. Results We detected a clear effect of catchment geodiversity on species richness, although the traditional local habitat and land use variables were the strongest predictors. Especially soil-type richness appeared as an important factor for species richness. While variables related to stream size were the most important for macroinvertebrate richness and partly for bacterial richness, the importance of water chemistry and land use for diatom richness was notable. Conclusions In addition to traditional environmental variables, geodiversity may affect species richness variation in streams, for example through changes in water chemistry. Geodiversity information could be used as a proxy for predicting stream species richness and offers a supplementary tool for conservation efforts.
  • Tuominen, Heidi; Rautava, Jaana; Kero, Katja; Syrjänen, Stina; Collado, Maria C; Rautava, Samuli (BioMed Central, 2021)
    Abstract Background Aberrant microbiota composition has been linked to disease development at numerous anatomical sites. Microbiota changes in reaction to viral infections, such as human papillomavirus (HPV), have been investigated almost exclusively in the female reproductive tract. However, HPV infection may also affect male health by reducing semen quality and fertility. The aim of this study was to investigate whether present HPV DNA is associated with detectable changes in semen bacterial microbiota composition and diversity. Methods This study relied on stored semen samples from 31 fertile healthy men who participated in the Finnish family HPV Study during the years 1998–2001. DNA was extracted from semen with PCR template preparation kit. HPV was genotyped using Luminex-based Multimetrix® assay. Microbiota was analyzed from the V3-V4 region of 16S rDNA gene following sequencing on an Illumina MiSeq platform. All statistical analyses were performed with Calypso software version 8.84. Results HPV DNA was detected in 19.4% (6/31) of the semen samples. HPV status in the semen did not impact the α-diversity estimations, as measured by Chao1 and Shannon indices, nor ß-diversity. Nevertheless, HPV-positive semen samples exhibited differences in the taxonomic composition of the bacterial microbiota including higher abundances of Moraxellaceae (p = 0.028), Streptococcus (p = 0.0058) and Peptostreptococcus (p = 0.012) compared to HPV-negative semen samples. Conclusion HPV infection is associated with altered bacterial microbiota composition in semen, and this might have in impact to male health in general. As of present, it is unclear whether these changes result from HPV infection or whether altered bacterial microbiota increases susceptibility to HPV infection. More research is needed on viral-bacterial interactions in the male reproductive system.
  • Muszer, Magdalena; Noszczynska, Magdalena; Kasperkiewicz, Katarzyna; Skurnik, Mikael (2015)
    The microorganisms that inhabit humans are very diverse on different body sites and tracts. Each specific niche contains a unique composition of the microorganisms that are important for a balanced human physiology. Microbial cells outnumber human cells by tenfold and they function as an invisible organ that is called the microbiome. Excessive use of antibiotics and unhealthy diets pose a serious danger to the composition of the microbiome. An imbalance in the microbial community may cause pathological conditions of the digestive system such as obesity, cancer and inflammatory bowel disease; of the skin such as atopic dermatitis, psoriasis and acne and of the cardiovascular system such as atherosclerosis. An unbalanced microbiome has also been associated with neurodevelopmental disorders such as autism and multiple sclerosis. While the microbiome has a strong impact on the development of the host immune system, it is suspected that it can also be the cause of certain autoimmune diseases, including diabetes or rheumatoid arthritis. Despite the enormous progress in the field, the interactions between the human body and its microbiome still remain largely unknown. A better characterization of the interactions may allow for a deeper understanding of human disease states and help to elucidate a possible association between the composition of the microbiome and certain pathologies. This review focuses on general findings that are related to the area and provides no detailed information about the case of study. The aim is to give some initial insight on the studies of the microbiome and its connection with human health.
  • Liljestrand, John M.; Paju, Susanna; Pietiäinen, Milla; Buhlin, Kåre; Persson, G. Rutger; Nieminen, Markku S.; Sinisalo, Juha; Mäntylä, Päivi; Pussinen, Pirkko J. (2018)
  • Ritari, Jarmo; Salojärvi, Jarkko; Lahti, Leo; de Vos, Willem M. (2015)
    Background: Current sequencing technology enables taxonomic profiling of microbial ecosystems at high resolution and depth by using the 16S rRNA gene as a phylogenetic marker. Taxonomic assignation of newly acquired data is based on sequence comparisons with comprehensive reference databases to find consensus taxonomy for representative sequences. Nevertheless, even with well-characterised ecosystems like the human intestinal microbiota it is challenging to assign genus and species level taxonomy to 16S rRNA amplicon reads. A part of the explanation may lie in the sheer size of the search space where competition from a multitude of highly similar sequences may not allow reliable assignation at low taxonomic levels. However, when studying a particular environment such as the human intestine, it can be argued that a reference database comprising only sequences that are native to the environment would be sufficient, effectively reducing the search space. Results: We constructed a 16S rRNA gene database based on high-quality sequences specific for human intestinal microbiota, resulting in curated data set consisting of 2473 unique prokaryotic species-like groups and their taxonomic lineages, and compared its performance against the Greengenes and Silva databases. The results showed that regardless of used assignment algorithm, our database improved taxonomic assignation of 16S rRNA sequencing data by enabling significantly higher species and genus level assignation rate while preserving taxonomic diversity and demanding less computational resources. Conclusion: The curated human intestinal 16S rRNA gene taxonomic database of about 2500 species-like groups described here provides a practical solution for significantly improved taxonomic assignment for phylogenetic studies of the human intestinal microbiota.
  • Romano, Javier Sanchez; Mork, Torill; Laaksonen, Sauli; Agren, Erik; Nymo, Ingebjorg H.; Sunde, Marianne; Tryland, Morten (2018)
    Background: Infectious keratoconjunctivitis (IKC) is one of the most common ocular diseases in ruminants worldwide. In addition to keratitis and conjunctivitis, animals with IKC can develop uveitis, corneal ulcer, and in severe cases, blindness. The bacteria Moraxella spp. has been described as the primary causative agent of infectious bovine keratoconjunctivitis (IBK) in cattle (Bos taurus), while Chlamydia spp. and Mycoplasma conjunctivae are considered the main causative agents of IKC in sheep (Ovis aries). Previous studies indicated cervid herpesvirus 2 (CvHV2) as the primary causative agent of IKC in semi-domesticated reindeer (Rangifer tarandus tarandus). The aim of the study was to investigate the presence and prevalence of potential pathogens for IKC in reindeer, and compare the ocular microbiota of animals with IKC, with apparently healthy animals. Results: Semi-domesticated reindeer (n = 341), with (n = 108) or without (n = 113) ocular clinical signs, or with no information on clinical status (n = 120), were sampled in Norway, Sweden and Finland in 2010-2014. Seroprevalence was 37.4% for alphaherpesvirus (95/254), 3.8% for gammaherpesvirus (8/211) and 7.1% for pestivirus (15/211) (ELISA). PCR analyses of conjunctival swab samples revealed a prevalence of 28.5% for CvHV2 (57/200), 11.9% for Chlamydiaceae (16/135) and 1.0% for M. conjunctivae (2/197). Bacteriological cultivation of 202 conjunctival swab samples revealed bacterial growth from 75.2% of the samples, with Moraxella spp. being isolated from 21.6% (11/51) of the animals with and 5.6% (5/84) without ocular clinical signs. A significant association (p <0.001) existed between the presence of clinical signs of IKC and CvHV2 DNA in the affected eyes, an association that was not present for other microorganisms. Conclusions: These results support the hypothesis that CvHV2 is the primary agent of IKC in semi-domesticated reindeer in Fennoscandia, with Moraxella bovoculi being a secondary candidate, since it was isolated in two different outbreaks of IKC. Further studies should be carried out to better understand the infection biology and the pathogenesis of IKC in reindeer.
  • Koivuniemi, Artturi; Fallarero, Adyary; Bunker, Alex (2019)
    The development of antimicrobial agents that target and selectively disrupt biofilms is a pressing issue since, so far, no antibiotics have been developed that achieve this effectively. Previous experimental work has found a promising set of antibacterial peptides: β2,2-amino acid derivatives, relatively small molecules with common structural elements composed of a polar head group and two non-polar hydrocarbon arms. In order to develop insight into possible mechanisms of action of these novel antibacterial agents, we have performed an in silico investigation of four leading β2,2-amino acid derivatives, interacting with models of both bacterial (target) and eukaryotic (host) membranes, using molecular dynamics simulation with a model with all-atom resolution. We found an unexpected result that could shed light on the mechanism of action of these antimicrobial agents: the molecules assume a conformation where one of the hydrophobic arms is directed downward into the membrane core while the other is directed upwards, out of the membrane and exposed above the position of the membrane headgroups; we dubbed this conformation the “can-can pose”. Intriguingly, the can-can pose was most closely linked to the choice of headgroup. Also, the compound previously found to be most effective against biofilms displayed the strongest extent of this behavior and, additionally, this behavior was more pronounced for this compound in the bacterial than in the eukaryotic membrane. We hypothesize that adopting the can-can pose could possibly disrupt the protective peptidoglycan macronet found on the exterior of the bacterial membrane.
  • 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.
  • Enroth, Johannes (2017)
  • Perdomo, Maria F.; Toppinen, Mari; Hedman, Klaus; Sajantila, Antti (2018)