- MeSH
- horké prameny * mikrobiologie MeSH
- sinice izolace a purifikace MeSH
- Geografické názvy
- Bulharsko MeSH
Genotypic and morphological diversity of cyanobacteria in the Rupite hot spring (Bulgaria) was investigated by means of optical microscopy, cultivation, single-cell PCR, and 16S rRNA gene amplicon sequencing. Altogether, 34 sites were investigated along the 71-39 °C temperature gradient. Analysis of samples from eight representative sites shown that Illumina, optical microscopy, and Roche 454 identified 72, 45 and 19% respective occurrences of all cumulatively present taxa. Optical microscopy failed to detect species of minor occurrence; whereas, amplicon sequencing technologies suffered from failed primer annealing and the presence of species with extensive extracellular polysaccharides production. Amplicon sequencing of the 16S rRNA gene V5-V6 region performed by Illumina identified the cyanobacteria most reliably to the generic level. Nevertheless, only the combined use of optical microscopy, cultivation and sequencing methods allowed for reliable estimate of the cyanobacterial diversity. Here, we show that Rupite hot-spring system hosts one of the richest cyanobacterial flora reported from a single site above 50 °C. Chlorogloeopsis sp. was the most abundant at the highest temperature (68 °C), followed by Leptolyngbya boryana, Thermoleptolyngbya albertanoae, Synechococcus bigranulatus, Oculatella sp., and Desertifilum sp. thriving above 60 °C, while Leptolyngbya geysericola, Geitlerinema splendidum, and Cyanobacterium aponinum were found above 50 °C.
Shark Bay, Western Australia is a World Heritage area with extensive microbial mats and stromatolites. Microbial communities that comprise these mats have developed a range of mitigation strategies against changing levels of photosynthetically active and ultraviolet radiation, including the ability to biosynthesise the UV-absorbing natural products scytonemin and mycosporine-like amino acids (MAAs). To this end, the distribution of photoprotective pigments within Shark Bay microbial mats was delineated in the present study. This involved amplicon sequencing of bacterial 16S rDNA from communities at the surface and subsurface in three distinct mat types (smooth, pustular and tufted), and correlating this data with the chemical and molecular distribution of scytonemin and MAAs. Employing UV spectroscopy and MS/MS fragmentation, mycosporine-glycine, asterina and an unknown MAA were identified based on typical fragmentation patterns. Marker genes for scytonemin and MAA production (scyC and mysC) were amplified from microbial mat DNA and placed into phylogenetic context against a broad screen throughout 363 cyanobacterial genomes. Results indicate that occurrence of UV screening compounds is associated with the upper layer of Shark Bay microbial mats, and the occurrence of scytonemin is closely dependent on the abundance of cyanobacteria.
- MeSH
- aminokyseliny metabolismus MeSH
- fenoly metabolismus MeSH
- fotosyntéza MeSH
- fylogeneze * MeSH
- glycin metabolismus MeSH
- indoly metabolismus MeSH
- mikrobiota účinky záření MeSH
- sinice klasifikace genetika izolace a purifikace metabolismus MeSH
- tandemová hmotnostní spektrometrie MeSH
- ultrafialové záření MeSH
- výpočetní biologie MeSH
- zátoky mikrobiologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Austrálie MeSH
Microbes transported by glacial meltwater streams are thought to be a product of passive dispersal from both supra- and subglacial sources, though studies investigating the origins of these assemblages are scarce. Here, we conducted a survey within a large catchment containing multiple glaciers on Qeqertarsuaq (Disko Island), west Greenland, to investigate whether meltwater-exported microbial assemblages in suspended sediments differ between glacial meltwater streams, and if they reflect corresponding bulk subglacial and extraglacial sediment communities. Using 16S rRNA gene amplicon sequencing, we found proglacial stream assemblages substantially differ from one another, despite their close spatial proximity. Furthermore, proglacial stream assemblages were composed of greater proportions of Cyanobacteria compared to bulk subglacial sediment communities, dominated by Betaproteobacteria, demonstrating large contributions of meltwater and microbial cells from supraglacial habitats. Corresponding physico-chemical characteristics of meltwater suggest that streams draining smaller glaciers had more equal contributions of both supra- and subglacial inputs compared with the main catchment outlet, aligning with observed changes in assemblage structure, such as the decreased proportion of Cyanobacteria. These results suggest that glacier size and hydrological drainage systems may influence the structure of exported microbial assemblages, and collectively provide insights into their formation and fate in thiscurrent age of deglaciation.
- MeSH
- Betaproteobacteria klasifikace genetika izolace a purifikace MeSH
- biodiverzita MeSH
- DNA bakterií genetika MeSH
- ekosystém MeSH
- geologické sedimenty mikrobiologie MeSH
- hydrologie MeSH
- ledový příkrov mikrobiologie MeSH
- ostrovy MeSH
- řeky mikrobiologie MeSH
- RNA ribozomální 16S genetika MeSH
- sekvence nukleotidů MeSH
- sekvenční analýza DNA MeSH
- sinice klasifikace genetika izolace a purifikace MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Grónsko MeSH
- ostrovy MeSH
Molecular and morphological methods were applied to study cyanobacterial community composition in biological soil crusts (BSCs) from four areas (two nunataks and two ridges) in the Sør Rondane Mountains, Antarctica. The sampling sites serve as control areas for open top chambers (OTCs) that were put in place in 2010 at the time of sample collection and will be compared with BSC samples taken from the OTCs in the future. Cyanobacterial cell biovolume was estimated using epifluorescence microscopy, which revealed the dominance of filamentous cyanobacteria in all studied sites except the Utsteinen ridge, where unicellular cyanobacteria were the most abundant. Cyanobacterial diversity was studied by a combination of molecular fingerprinting methods based on the 16S rRNA gene (denaturing gradient gel electrophoresis (DGGE) and 454 pyrosequencing) using cyanobacteria-specific primers. The number of DGGE sequences obtained per site was variable and, therefore, a high-throughput method was subsequently employed to improve the diversity coverage. Consistent with previous surveys in Antarctica, both methods showed that filamentous cyanobacteria, such as Leptolyngbya sp., Phormidium sp. and Microcoleus sp., were dominant in the studied sites. In addition, the studied localities differed in substrate type, climatic conditions and soil parameters, which probably resulted in differences in cyanobacterial community composition. Furthermore, the BSC growing on gneiss pebbles had lower cyanobacterial abundances than BSCs associated with granitic substrates.
- MeSH
- biodiverzita MeSH
- DNA bakterií genetika MeSH
- ekosystém MeSH
- ledový příkrov mikrobiologie MeSH
- molekulární typizace MeSH
- půdní mikrobiologie * MeSH
- RNA ribozomální 16S genetika MeSH
- sekvenční analýza DNA MeSH
- sinice * klasifikace genetika izolace a purifikace MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Antarktida MeSH
The biochemical responses of rock-inhabiting cyanobacteria towards native environmental stresses were observed in vivo in one of the Earth's most challenging extreme climatic environments. The cryptoendolithic cyanobacterial colonization, dominated by Chroococcidiopsis sp., was studied in an ignimbrite at a high altitude volcanic area in the Atacama Desert, Chile. Change in the carotenoid composition (red-shift) within a transect through the cyanobacteria dominant microbial community (average thickness ~1 mm) was unambiguously revealed in their natural endolithic microhabitat. The amount of red shifted carotenoid, observed for the first time in a natural microbial ecosystem, is depth dependent, and increased with increasing proximity to the rock surface, as proven by resonance Raman imaging and point resonance Raman profiling. It is attributed to a light-dependent change in carotenoid conjugation, associated with the light-adaptation strategy of cyanobacteria. A hypothesis is proposed for the possible role of an orange carotenoid protein (OCP) mediated non-photochemical quenching (NPQ) mechanism that influences the observed spectral behavior. Simultaneously, information about the distribution of scytonemin and phycobiliproteins was obtained. Scytonemin was detected in the uppermost cyanobacteria aggregates. A reverse signal intensity gradient of phycobiliproteins was registered, increasing with deeper positions as a response of the cyanobacterial light harvesting complex to low-light conditions.
- MeSH
- biologické pigmenty MeSH
- ekosystém MeSH
- fluorescenční mikroskopie MeSH
- karotenoidy chemie metabolismus MeSH
- konfokální mikroskopie MeSH
- mikrobiologie životního prostředí MeSH
- pouštní klima * MeSH
- sinice * izolace a purifikace metabolismus MeSH
- spektrální analýza MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The environment of high-altitudinal cold deserts of Western Himalaya is characterized by extensive development of biological soil crusts, with cyanobacteria as dominant component. The knowledge of their taxonomic composition and dependency on soil chemistry and elevation is still fragmentary. We studied the abundance and the phylogenetic diversity of the culturable cyanobacteria and eukaryotic microalgae in soil crusts along altitudinal gradients (4600-5900 m) at two sites in the dry mountains of Ladakh (SW Tibetan Plateau and Eastern Karakoram), using both microscopic and molecular approaches. The effects of environmental factors (altitude, mountain range, and soil physico-chemical parameters) on the composition and biovolume of phototrophs were tested by multivariate redundancy analysis and variance partitioning. Both phylogenetic diversity and composition of morphotypes were similar between Karakorum and Tibetan Plateau. Phylogenetic analysis of 16S rRNA gene revealed strains belonging to at least five genera. Besides clusters of common soil genera, e.g., Microcoleus, Nodosilinea, or Nostoc, two distinct clades of simple trichal taxa were newly discovered. The most abundant cyanobacterial orders were Oscillatoriales and Nostacales, whose biovolume increased with increasing elevation, while that of Chroococales decreased. Cyanobacterial species richness was low in that only 15 morphotypes were detected. The environmental factors accounted for 52 % of the total variability in microbial data, 38.7 % of which was explained solely by soil chemical properties, 14.5 % by altitude, and 8.4 % by mountain range. The elevation, soil phosphate, and magnesium were the most important predictors of soil phototrophic communities in both mountain ranges despite their different bedrocks and origin. The present investigation represents a first record on phylogenetic diversity of the cyanobacterial community of biological soil crusts from Western Himalayas and first record from altitudes over 5000 m.
- MeSH
- biodegradace MeSH
- biodiverzita * MeSH
- fylogeneze * MeSH
- geologické sedimenty analýza mikrobiologie MeSH
- molekulární sekvence - údaje MeSH
- nadmořská výška MeSH
- půda chemie MeSH
- půdní mikrobiologie * MeSH
- sinice klasifikace genetika izolace a purifikace metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Tibet MeSH
While photoautotrophic organisms are an important component of biofilms that live in certain regions of natural draft cooling towers, little is known about these communities. We therefore examined 18 towers at nine sites to identify the general patterns of community assembly in three distinct tower parts, and we examined how community structures differ depending on geography. We also compared the newly acquired data with previously published data. The bottom sections of draft cooling towers are mainly settled by large filamentous algae, primarily Cladophora glomerata. The central portions of towers host a small amount of planktic algae biomass originating in the cooling water. The upper fourths of towers are colonized by biofilms primarily dominated by cyanobacteria, e.g., members of the genera Gloeocapsa and Scytonema. A total of 41 taxa of phototrophic microorganisms were identified. Species composition of the upper fourth of all towers was significantly affected by cardinal position. There was different species composition at positions facing north compared to positions facing south. West- and east-facing positions were transitory and highly similar to each other in terms of species composition. Biofilms contribute to the degradation of paint coatings inside towers.
In situ nitrogen fixation was investigated in a cyanobacterial mat growing on the bed of rocks of the Muga River, Spain. The filamentous non-heterocystous cyanobacterium Schizothrix dominated the mat, showing nitrogenase activity in the light at similar rates to those found in nearby heterocystous Rivularia colonies. N2 fixation in the light was significantly increased by an inhibitor of PSII and oxygen evolution, DCMU (3-[3,4-dichlorophenyl]-1,1-dimethylurea), and anaerobic conditions. However, no nitrogenase activity was found in the dark. Addition of fructose as a respiratory substrate induced nitrogenase activity in samples incubated under aerobic conditions in the dark but not in anaerobic conditions. Microelectrode oxygen profiles showed internal microaerobic microzones where nitrogen fixation might concentrate. Analyses of the 16S rRNA gene revealed only the presence of sequences belonging to filamentous non-heterocystous cyanobacteria. nifH gene diversity showed that the major phylotypes also belonged to this group. One of the three strains isolated from the Schizothrix mat was capable of fixing N2 and growing in the absence of combined N. This was consistent with the nifH gene analysis. These results suggest a relevant contribution of non-heterocystous cyanobacteria to nitrogen fixation in these mats.
Microbial mats are abundant in many alpine and polar aquatic ecosystems. With warmer temperatures, new hydrologic pathways are developing in these regions and increasing dissolved nutrient fluxes. In the McMurdo Dry Valleys, thermokarsting may release both nutrients and sediment, and has the potential to influence mats in glacial meltwater streams. To test the role of nutrient inputs on community structure, we created nutrient diffusing substrata (NDS) with agar enriched in N, P and N + P, with controls, and deployed them into two Dry Valley streams. We found N amendments (N and N + P) to have greater chlorophyll-a concentrations, total algal biovolume, more fine filamentous cyanobacteria and a higher proportion of live diatoms than other treatments. Furthermore, N treatments were substantially elevated in Bacteroidetes and the small diatom, Fistulifera pelliculosa. On the other hand, species richness was almost double in P and N + P treatments over others, and coccoid green algae and Proteobacteria were more abundant in both streams. Collectively, these data suggest that nutrients have the potential to stimulate growth and alter community structure in glacial meltwater stream microbial mats, and the recent erosion of permafrost and accelerated glacial melt will likely impact resident biota in polar lotic systems here and elsewhere.
- MeSH
- chlorofyl analýza MeSH
- Chlorophyta metabolismus MeSH
- dusík analýza MeSH
- ekosystém MeSH
- fosfor analýza MeSH
- ledový příkrov mikrobiologie MeSH
- Proteobacteria izolace a purifikace metabolismus MeSH
- řeky mikrobiologie MeSH
- rozsivky izolace a purifikace metabolismus MeSH
- sinice izolace a purifikace metabolismus MeSH
- společenstvo MeSH
- teplota MeSH
- Publikační typ
- časopisecké články MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Geografické názvy
- Antarktida MeSH
