Ecology of microbial communities in the sulfidic ore environments

1 Abstract This thesis is focused on the diversity of microorganisms of prokaryotic type living in the environments, where microbial sulfidic mineral precipitation or decomposition occur. The relationship between the microbial community composition and geochemical processes was examined. To the best of our knowledge, we were the first to analyze microbial communities from gossan and their significance for the ecosystem of a large sulfidic ore deposit. In addition, we compared the microbial assemblies at multiple habitats associated with generation or transformation of acidic mine drainage (AMD) and described niche partitioning among closely related organisms. The unexpectedly variable communities in stalactites growing on the AMD springs were utilized as a model for assessing neutral variability of the microbial communities. They clustered almost randomly even though the environmental conditions corresponded with the localities. This is an important difference of the simple communities from stalactites and the common highly diversified microbial assemblies. The communities found in sediments, soil, and many other complex substrates usually reveal high correlation with their environment. We propose that neutral fluctuations of the community composition are suppressed by averaging multiple physically...1 Abstrakt Tato práce se zaměřuje na diverzitu mikroorganismů prokaryotického typu žijících v prostředí mikrobiální dekompozice i tvorby sulfidických minerálů a zkoumá zde vztah mezi složením mikrobiálních komunit a geochemickými procesy. V prostředí rozsáhlého a částečně vytěženého ložiska sulfidických rud byly poprvé charakterizovány mikrobiální komunity v gossanu a jejich role v rámci ekosystému. Kromě toho byla srovnána mikrobiální společenstva ze stanovišť typických pro tvorbu a přeměny kyselých důlních vod (AMD) a byla nalezena diferenciace nik mezi příbuznými mikroorganismy. Nález neobvykle variabilních mikrobiálních komunit v biostalaktitech rostoucích na vývěrech AMD byl využit pro detekci neutrální variability mikrobiálních společenstev. Bylo zjištěno, že jednoduché mikrobiální komunity nevykazují podobnost podle lokality, ačkoliv podobnost prostředí lokalitám odpovídala, ale převážně náhodně. Tím se jednoduché komunity liší od vysoce diverzifikovaných společenstev z půdy, sedimentů a dalších komplexních substrátů, které vykazují vysokou korelaci bioty s faktory prostředí. Předpokládaná příčina tohoto rozdílu je kompozitní charakter bohatých komunit a potlačení náhodných fluktuací průměrováním velkého počtu fyzicky oddělených mikrokomunit. Tomu nasvědčuje i fakt, že podobnost jednoduchých komunit...Department of ZoologyKatedra zoologieFaculty of SciencePřírodovědecká fakult

Patterns in Microbial Assemblages Exported From the Meltwater of Arctic and Sub-Arctic Glaciers

Meltwater streams connect the glacial cryosphere with downstream ecosystems. Dissolved and particulate matter exported from glacial ecosystems originates from contrasting supraglacial and subglacial environments, and exported microbial cells have the potential to serve as ecological and hydrological indicators for glacial ecosystem processes. Here, we compare exported microbial assemblages from the meltwater of 24 glaciers from six (sub)Arctic regions - the southwestern Greenland Ice Sheet, Qeqertarsuaq (Disko Island) in west Greenland, Iceland, Svalbard, western Norway, and southeast Alaska - differing in their lithology, catchment size, and climatic characteristics, to investigate spatial and environmental factors structuring exported meltwater assemblages. We found that 16S rRNA gene sequences of all samples were dominated by the phyla Proteobacteria, Bacteroidetes, and Actinobacteria, with Verrucomicrobia also common in Greenland localities. Clustered OTUs were largely composed of aerobic and anaerobic heterotrophs capable of degrading a wide variety of carbon substrates. A small number of OTUs dominated all assemblages, with the most abundant being from the genera Polaromonas, Methylophilus, and Nitrotoga. However, 16-32% of a region's OTUs were unique to that region, and rare taxa revealed unique metabolic potentials and reflected differences between regions, such as the elevated relative abundances of sulfur oxidizers Sulfuricurvum sp. and Thiobacillus sp. at Svalbard sites. Meltwater alpha diversity showed a pronounced decrease with increasing latitude, and multivariate analyses of assemblages revealed significant regional clusters. Distance-based redundancy and correlation analyses further resolved associations between whole assemblages and individual OTUs with variables primarily corresponding with the sampled regions. Interestingly, some OTUs indicating specific metabolic processes were not strongly associated with corresponding meltwater characteristics (e.g., nitrification and inorganic nitrogen concentrations). Thus, while exported assemblage structure appears regionally specific, and probably reflects differences in dominant hydrological flowpaths, OTUs can also serve as indicators for more localized microbially mediated processes not captured by the traditional characterization of bulk meltwater hydrochemistry. These results collectively promote a better understanding of microbial distributions across the Arctic, as well as linkages between the terrestrial cryosphere habitats and downstream ecosystems

Catchment characteristics and seasonality control the composition of microbial assemblages exported from three outlet glaciers of the Greenland Ice Sheet

Glacial meltwater drains into proglacial rivers where it interacts with the surrounding landscape, collecting microbial cells as it travels downstream. Characterizing the composition of the resulting microbial assemblages in transport can inform us about intra-annual changes in meltwater flowpaths beneath the glacier as well as hydrological connectivity with proglacial areas. Here, we investigated how the structure of suspended microbial assemblages evolves over the course of a melt season for three proglacial catchments of the Greenland Ice Sheet (GrIS), reasoning that differences in glacier size and the proportion of glacierized versus non-glacierized catchment areas will influence both the identity and relative abundance of microbial taxa in transport. Streamwater samples were taken at the same time each day over a period of 3 weeks (summer 2018) to identify temporal patterns in microbial assemblages for three outlet glaciers of the GrIS, which differed in glacier size (smallest to largest; Russell, Leverett, and Isunnguata Sermia [IS]) and their glacierized: proglacial catchment area ratio (Leverett, 76; Isunnguata Sermia, 25; Russell, 2). DNA was extracted from samples, and 16S rRNA gene amplicons sequenced to characterize the structure of assemblages. We found that microbial diversity was significantly greater in Isunnguata Sermia and Russell Glacier rivers compared to Leverett Glacier, the latter of which having the smallest relative proglacial catchment area. Furthermore, the microbial diversity of the former two catchments continued to increase over monitored period, presumably due to increasing hydrologic connectivity with proglacial habitats. Meanwhile, diversity decreased over the monitored period in Leverett, which may have resulted from the evolution of an efficient subglacial drainage system. Linear discriminant analysis further revealed that bacteria characteristic to soils were disproportionately represented in the Isunnguata Sermia river, while putative methylotrophs were disproportionately abundant in Russell Glacier. Meanwhile, taxa typical for glacierized habitats (i.e., Rhodoferax and Polaromonas) dominated in the Leverett Glacier river. Our findings suggest that the proportion of deglaciated catchment area is more influential to suspended microbial assemblage structure than absolute glacier size, and improve our understanding of hydrological flowpaths, particulate entrainment, and transport

Increasing Incidence of Geomyces destructans Fungus in Bats from the Czech Republic and Slovakia

BACKGROUND: White-nose syndrome is a disease of hibernating insectivorous bats associated with the fungus Geomyces destructans. It first appeared in North America in 2006, where over a million bats died since then. In Europe, G. destructans was first identified in France in 2009. Its distribution, infection dynamics, and effects on hibernating bats in Europe are largely unknown. METHODOLOGY/PRINCIPAL FINDINGS: We screened hibernacula in the Czech Republic and Slovakia for the presence of the fungus during the winter seasons of 2008/2009 and 2009/2010. In winter 2009/2010, we found infected bats in 76 out of 98 surveyed sites, in which the majority had been previously negative. A photographic record of over 6000 hibernating bats, taken since 1994, revealed bats with fungal growths since 1995; however, the incidence of such bats increased in Myotis myotis from 2% in 2007 to 14% by 2010. Microscopic, cultivation and molecular genetic evaluations confirmed the identity of the recently sampled fungus as G. destructans, and demonstrated its continuous distribution in the studied area. At the end of the hibernation season we recorded pathologic changes in the skin of the affected bats, from which the fungus was isolated. We registered no mass mortality caused by the fungus, and the recorded population decline in the last two years of the most affected species, M. myotis, is within the population trend prediction interval. CONCLUSIONS/SIGNIFICANCE: G. destructans was found to be widespread in the Czech Republic and Slovakia, with an epizootic incidence in bats during the most recent years. Further development of the situation urgently requires a detailed pan-European monitoring scheme

Large subglacial source of mercury from the southwestern margin of the Greenland Ice Sheet

The Greenland Ice Sheet is currently not accounted for in Arctic mercury budgets, despite large and increasing annual runoff to the ocean and the socio-economic concerns of high mercury levels in Arctic organisms. Here we present concentrations of mercury in meltwaters from three glacial catchments on the southwestern margin of the Greenland Ice Sheet and evaluate the export of mercury to downstream fjords based on samples collected during summer ablation seasons. We show that concentrations of dissolved mercury are among the highest recorded in natural waters and mercury yields from these glacial catchments (521–3,300 mmol km−2 year−1) are two orders of magnitude higher than from Arctic rivers (4–20 mmol km−2 year−1). Fluxes of dissolved mercury from the southwestern region of Greenland are estimated to be globally significant (15.4–212 kmol year−1), accounting for about 10% of the estimated global riverine flux, and include export of bioaccumulating methylmercury (0.31–1.97 kmol year−1). High dissolved mercury concentrations (~20 pM inorganic mercury and ~2 pM methylmercury) were found to persist across salinity gradients of fjords. Mean particulate mercury concentrations were among the highest recorded in the literature (~51,000 pM), and dissolved mercury concentrations in runoff exceed reported surface snow and ice values. These results suggest a geological source of mercury at the ice sheet bed. The high concentrations of mercury and its large export to the downstream fjords have important implications for Arctic ecosystems, highlighting an urgent need to better understand mercury dynamics in ice sheet runoff under global warming

Ecology of microbial communities in the sulfidic ore environments

1 Abstract This thesis is focused on the diversity of microorganisms of prokaryotic type living in the environments, where microbial sulfidic mineral precipitation or decomposition occur. The relationship between the microbial community composition and geochemical processes was examined. To the best of our knowledge, we were the first to analyze microbial communities from gossan and their significance for the ecosystem of a large sulfidic ore deposit. In addition, we compared the microbial assemblies at multiple habitats associated with generation or transformation of acidic mine drainage (AMD) and described niche partitioning among closely related organisms. The unexpectedly variable communities in stalactites growing on the AMD springs were utilized as a model for assessing neutral variability of the microbial communities. They clustered almost randomly even though the environmental conditions corresponded with the localities. This is an important difference of the simple communities from stalactites and the common highly diversified microbial assemblies. The communities found in sediments, soil, and many other complex substrates usually reveal high correlation with their environment. We propose that neutral fluctuations of the community composition are suppressed by averaging multiple physically..

Phosphodiesterases 8a and 8b - potential components of membrane rafts

Katedra fyziol. živočichů a vývoj. biol. (zrušena)Dep. of Physiology and Develop. Biology (obsolete)Přírodovědecká fakultaFaculty of Scienc

Clonning and characterization of the membrane microdomain targeted componets

3 Abstract Lipid rafts are defined as islets in the membranes of eucaryotic cells with different composition from the rest of the membrane. They appear spontaneously due to phase separation of different membrane components and are proposed to serve as platforms for concentration of selected signaling proteins. However, evidence for their existence is still indirect, despite more than decade of intense research. Some new approaches show that the fluctuations of membrane composition are more diverse and are caused more likely by presence of proteins than by lipid phase separation. We performed bioinformatical search looking for new signaling proteins targeted to putative rafts. We have identified several proteins and out of them phosphodiesterase 8a (PDE 8a) was salected for further research. To prepare the mouse monoclonal antibody we expressed and purified fragment of PDE 8a fused with GST. After immunisation we obtained one clone producing antibodies tentatively positive on western blot and by indirect immunofluorescence. We predicted that PDE 8a is targeted to putative rafts by N-terminal myristoylation and palmitoylation. To clarify, whether these modifications are present in the strusture of PDE 8a we prepared mutants of the PDE 8a N-terminal region lacking myristoylation, palmitoylation or both. These..