scholarly journals Environmental controls on bacteriohopanepolyol profiles of benthic microbial mats from Lake Fryxell, Antarctica

Geobiology ◽  
2019 ◽  
Vol 17 (5) ◽  
pp. 551-563 ◽  
Author(s):  
Emily D. Matys ◽  
Tyler Mackey ◽  
Christen Grettenberger ◽  
Elliott Mueller ◽  
Anne Jungblut ◽  
...  
Keyword(s):  
Microbial Mats ◽  
Environmental Controls ◽  
Lake Fryxell

scholarly journals Putative Transposases Conserved in Exiguobacterium Isolates from Ancient Siberian Permafrost and from Contemporary Surface Habitats

2005 ◽  
Vol 71 (11) ◽  
pp. 6954-6962 ◽  
Author(s):  
Tatiana A. Vishnivetskaya ◽  
Sophia Kathariou
Keyword(s):  
Surface Water ◽  
High Resolution ◽  
Food Processing ◽  
Microbial Mats ◽  
Genomic Diversity ◽  
Insertion Sequences ◽  
Gram Positive Bacteria ◽  
Lake Fryxell ◽  
Siberian Permafrost ◽  
Type Strains

ABSTRACT Gram-positive bacteria of the genus Exiguobacterium have been repeatedly isolated from Siberian permafrost ranging in age from 20,000 to 2 to 3 million years and have been sporadically recovered from markedly diverse habitats, including microbial mats in Lake Fryxell (Antarctic), surface water, and food-processing environments. However, there is currently no information on genomic diversity of this microorganism or on the physiological strategies that have allowed its survival under prolonged freezing in the permafrost. Analysis of the genome sequence of the most ancient available Exiguobacterium isolate (Exiguobacterium sp. strain 255-15, from 2 to 3 million-year-old Siberian permafrost) revealed numerous putative transposase sequences, primarily of the IS200/IS605, IS30, and IS3 families, with four transposase families identified. Several of the transposase genes appeared to be part of insertion sequences. Southern blots with different transposase probes yielded high-resolution genomic fingerprints which differentiated the different permafrost isolates from each other and from the Exiguobacterium spp. type strains which have been derived from diverse surface habitats. Each of the Exiguobacterium sp. strain 255-15 transposases that were used as probes had highly conserved homologs in the genome of other Exiguobacterium strains, both from permafrost and from modern sites. These findings suggest that, prior to their entrapment in permafrost, Exiguobacterium isolates had acquired transposases and that conserved transposases are present in Exiguobacterium spp., which now can be isolated from various modern surface habitats.

PHYLOGENETIC DIVERSITY OF THE MICROBIAL MATS IN LAKE FRYXELL, ANTARCTICA

2016 ◽  
Author(s):  
Megan Krusor ◽  
◽  
Ian Hawes ◽  
Anne Jungblut ◽  
Tyler J. Mackey ◽  
...  
Keyword(s):  
Phylogenetic Diversity ◽  
Microbial Mats ◽  
Lake Fryxell

Gillisia limnaea gen. nov., sp. nov., a new member of the family Flavobacteriaceae isolated from a microbial mat in Lake Fryxell, Antarctica

2004 ◽  
Vol 54 (2) ◽  
pp. 445-448 ◽  
Author(s):  
Stefanie Van Trappen ◽  
Ilse Vandecandelaere ◽  
Joris Mergaert ◽  
Jean Swings
Keyword(s):  
New Genus ◽  
Microbial Mats ◽  
Novel Species ◽  
Rrna Gene ◽  
Dry Valleys ◽  
Fatty Acid Profiles ◽  
16S Rrna Gene Sequences ◽  
The Family ◽  
Lake Fryxell ◽  
Distinct Lineage

A taxonomic study was performed on three strains isolated from microbial mats in Lake Fryxell, McMurdo Dry Valleys, Antarctica. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains belong to the family Flavobacteriaceae, in which they form a distinct lineage. The isolates are Gram-negative, chemoheterotrophic, aerobic, rod-shaped cells. They are psychrophilic and yellow-pigmented, with DNA G+C contents in the range 37·8–38·9 mol%. Whole-cell fatty acid profiles revealed mainly branched fatty acids and 17 : 0 2-OH. On the basis of genotypic, phenotypic, chemotaxonomic and phylogenetic results, it is proposed that the isolates represent a novel species in a new genus, Gillisia limnaea gen. nov., sp. nov. The type strain is LMG 21470T (=DSM 15749T).

scholarly journals Genome Sequence of Exiguobacterium antarcticum B7, Isolated from a Biofilm in Ginger Lake, King George Island, Antarctica

2012 ◽  
Vol 194 (23) ◽  
pp. 6689-6690 ◽  
Author(s):  
Adriana Ribeiro Carneiro ◽  
Rommel Thiago Jucá Ramos ◽  
Hivana Dall'Agnol ◽  
Anne Cybelle Pinto ◽  
Siomar de Castro Soares ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Antarctic Peninsula ◽  
Low Temperatures ◽  
Microbial Mats ◽  
King George Island ◽  
Content Type ◽  
Lake Fryxell ◽  
Mechanisms Of Adaptation ◽  
First Time ◽  
Exiguobacterium Antarcticum

ABSTRACTExiguobacterium antarcticumis a psychotropic bacterium isolated for the first time from microbial mats of Lake Fryxell in Antarctica. Many organisms of the genusExiguobacteriumare extremophiles and have properties of biotechnological interest, e.g., the capacity to adapt to cold, which make this genus a target for discovering new enzymes, such as lipases and proteases, in addition to improving our understanding of the mechanisms of adaptation and survival at low temperatures. This study presents the genome ofE. antarcticumB7, isolated from a biofilm sample of Ginger Lake on King George Island, Antarctic peninsula.

scholarly journals Energetic and Environmental Constraints on the Community Structure of Benthic Microbial Mats in Lake Fryxell, Antarctica

2019 ◽  
Author(s):  
Megan L. Dillon ◽  
Ian Hawes ◽  
Anne D. Jungblut ◽  
Tyler J. Mackey ◽  
Jonathan A. Eisen ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Communities ◽  
Energy Flow ◽  
Energy Use ◽  
Microbial Mats ◽  
Environmental Gradients ◽  
Dependent Manner ◽  
Ecological Communities ◽  
Overlying Water ◽  
Lake Fryxell

AbstractEcological communities are commonly thought to be controlled by the dynamics of energy flow through environments. Two of the most important energetic constraints on all communities are photosynthetically active radiation (PAR) and oxygen concentration ([O2]). Microbial mats growing on the bottom of Lake Fryxell, Antarctica, span environmental gradients in PAR and [O2], which we used to test the extent to which each controls community structure. Metagenomic analyses showed variation in the diversity and relative abundances of Archaea, Bacteria, and Eukaryotes across three [O2] and PAR conditions. Where [O2] saturated the mats or was absent from the overlying water, PAR structured the community. Where [O2] varied within mats, microbial communities changed across covarying PAR and [O2] gradients. Diversity negatively correlated with [O2] and PAR through mat layers in each habitat suggesting that, on the millimeter-scale, communities are structured by the optimization of energy use. In contrast, [O2] positively correlated with diversity and affected the distribution of dominant populations across the three habitats, suggesting that meter-scale diversity is structured by energy availability. The benthic microbial communities in Lake Fryxell are thus structured by energy flow in a scale-dependent manner.

scholarly journals Environmental controls and habitat connectivity of phototrophic microbial mats and bacterioplankton communities in an Antarctic freshwater system

2020 ◽  
Author(s):  
J. Ramoneda ◽  
I. Hawes ◽  
A. Pascual-García ◽  
T.J. Mackey ◽  
D.Y. Sumner ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Microbial Mats ◽  
Environmental Filtering ◽  
Freshwater Ecosystems ◽  
Habitat Conditions ◽  
Environmental Controls ◽  
Rrna Sequencing ◽  
Freshwater System ◽  
Halogenated Aromatic Compounds ◽  
Planktonic Communities

AbstractFreshwater ecosystems are considered hotspots of biodiversity in Antarctic polar deserts. Anticipated warming is expected to change the hydrology of these systems due to increased meltwater and reduction of ice cover, with implications for environmental conditions and physical connectivity between habitats. Using 16S rRNA sequencing, we evaluated the structure of microbial mat and planktonic communities within a connected watershed in the McMurdo Wright Valley, Antarctica to determine the roles of connectivity and habitat conditions in controlling microbial assemblage composition. We examined benthic and planktonic samples from glacial Lake Brownworth, the perennially ice-covered Lake Vanda, and the Onyx River, which connects the two. In Lake Vanda, we found distinct microbial assemblages occupying sub-habitats at different lake depths, while the communities from Lake Brownworth and Onyx River were structurally similar between them. Despite the higher connectivity between bacterial communities in the shallow parts of the system, environmental filtering dominated over dispersal in driving bacterial community structure. Functional metagenomics predictions identified genes related to degradation of halogenated aromatic compounds in surface microbial mats exposed to changes in water regimes, which progressively disappeared with increasing depth. Shifting environmental conditions due to increasing connectivity, rather than dispersal, may become the dominant drivers of bacterial diversity and functioning in Antarctic freshwater ecosystems.

scholarly journals Environmental control on the distribution of metabolic strategies of benthic microbial mats in Lake Fryxell, Antarctica

PLoS ONE ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. e0231053
Author(s):  
Megan L. Dillon ◽  
Ian Hawes ◽  
Anne D. Jungblut ◽  
Tyler J. Mackey ◽  
Jonathan A. Eisen ◽  
...  
Keyword(s):  
Microbial Mats ◽  
Environmental Control ◽  
Lake Fryxell ◽  
Metabolic Strategies

scholarly journals Energetic and Environmental Constraints on the Community Structure of Benthic Microbial Mats in Lake Fryxell, Antarctica

2020 ◽  
Vol 96 (2) ◽  
Author(s):  
Megan L Dillon ◽  
Ian Hawes ◽  
Anne D Jungblut ◽  
Tyler J Mackey ◽  
Jonathan A Eisen ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Communities ◽  
Energy Flow ◽  
Energy Use ◽  
Microbial Mats ◽  
Environmental Gradients ◽  
Ecological Communities ◽  
Lake Fryxell ◽  
High O2 ◽  
Lower Maximum

ABSTRACT Ecological communities are regulated by the flow of energy through environments. Energy flow is typically limited by access to photosynthetically active radiation (PAR) and oxygen concentration (O2). The microbial mats growing on the bottom of Lake Fryxell, Antarctica, have well-defined environmental gradients in PAR and (O2). We analyzed the metagenomes of layers from these microbial mats to test the extent to which access to oxygen and light controls community structure. We found variation in the diversity and relative abundances of Archaea, Bacteria and Eukaryotes across three (O2) and PAR conditions: high (O2) and maximum PAR, variable (O2) with lower maximum PAR, and low (O2) and maximum PAR. We found distinct communities structured by the optimization of energy use on a millimeter-scale across these conditions. In mat layers where (O2) was saturated, PAR structured the community. In contrast, (O2) positively correlated with diversity and affected the distribution of dominant populations across the three habitats, suggesting that meter-scale diversity is structured by energy availability. Microbial communities changed across covarying gradients of PAR and (O2). The comprehensive metagenomic analysis suggests that the benthic microbial communities in Lake Fryxell are structured by energy flow across both meter- and millimeter-scales.

Disentangling the role of shared ancestry and the environment on leaf stable isotopes

2019 ◽  
Author(s):  
Marko J. Spasojevic ◽  
Sören Weber1
Keyword(s):  
Stable Isotopes ◽  
Environmental Conditions ◽  
Evolutionary History ◽  
Environmental Control ◽  
Phylogenetic Signal ◽  
Individual Species ◽  
Habitat Types ◽  
Δ13c And Δ15n ◽  
Environmental Controls ◽  
Shared Ancestry

Stable carbon (C) and nitrogen (N) isotopes in plants are important indicators of plant water use efficiency and N acquisition strategies. While often regarded as being under environmental control, there is growing evidence that evolutionary history may also shape variation in stable isotope ratios (δ13C and δ15N) among plant species. Here we examined patterns of foliar δ13C and δ15N in alpine tundra for 59 species in 20 plant families. To assess the importance of environmental controls and evolutionary history, we examined if average δ13C and δ15N predictably differed among habitat types, if individual species exhibited intraspecific trait variation (ITV) in δ13C and δ15N, and if there were a significant phylogenetic signal in δ13C and δ15N. We found that variation among habitat types in both δ13C and δ15N mirrored well-known patterns of water and nitrogen limitation. Conversely, we also found that 40% of species exhibited no ITV in δ13C and 35% of species exhibited no ITV in δ15N, suggesting that some species are under stronger evolutionary control. However, we only found a modest signal of phylogenetic conservatism in δ13C and no phylogenetic signal in δ15N suggesting that shared ancestry is a weaker driver of tundra wide variation in stable isotopes. Together, our results suggest that both evolutionary history and local environmental conditions play a role in determining variation in δ13C and δ15N and that considering both factors can help with interpreting isotope patterns in nature and with predicting which species may be able to respond to rapidly changing environmental conditions.

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