scholarly journals Unveiling Ecological and Genetic Novelty within Lytic and Lysogenic Viral Communities of Hot Spring Phototrophic Microbial Mats

2021 ◽  
Author(s):  
Sergio Guajardo-Leiva ◽  
Fernando Santos ◽  
Oscar Salgado ◽  
Christophe Regeard ◽  
Laurent Quillet ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Community Ecology ◽  
Microbial Mats ◽  
Hot Springs ◽  
Hot Spring ◽  
Active Components ◽  
Viral Communities ◽  
Genetic Novelty ◽  
Abiotic Interactions

Hot springs harbor microbial communities dominated by a limited variety of microorganisms and, as such, have become a model for studying community ecology and understanding how biotic and abiotic interactions shape their structure. Viruses in hot springs are shown to be ubiquitous, numerous, and active components of these communities.

scholarly journals In-Situ Metatranscriptomic Analyses Reveal the Metabolic Flexibility of the Thermophilic Anoxygenic Photosynthetic Bacterium Chloroflexusaggregans in a Hot Spring Cyanobacteria-Dominated Microbial Mat

2021 ◽  
Vol 9 (3) ◽  
pp. 652
Author(s):  
Shigeru Kawai ◽  
Joval N. Martinez ◽  
Mads Lichtenberg ◽  
Erik Trampe ◽  
Michael Kühl ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Environmental Conditions ◽  
Microbial Mats ◽  
Carbon Fixation ◽  
Hot Springs ◽  
Hot Spring ◽  
Photosynthetic Bacterium ◽  
Early Morning ◽  
Metabolic Flexibility

Chloroflexus aggregans is a metabolically versatile, thermophilic, anoxygenic phototrophic member of the phylum Chloroflexota (formerly Chloroflexi), which can grow photoheterotrophically, photoautotrophically, chemoheterotrophically, and chemoautotrophically. In hot spring-associated microbial mats, C. aggregans co-exists with oxygenic cyanobacteria under dynamic micro-environmental conditions. To elucidate the predominant growth modes of C. aggregans, relative transcription levels of energy metabolism- and CO2 fixation-related genes were studied in Nakabusa Hot Springs microbial mats over a diel cycle and correlated with microscale in situ measurements of O2 and light. Metatranscriptomic analyses indicated two periods with different modes of energy metabolism of C. aggregans: (1) phototrophy around midday and (2) chemotrophy in the early morning hours. During midday, C. aggregans mainly employed photoheterotrophy when the microbial mats were hyperoxic (400–800 µmol L−1 O2). In the early morning hours, relative transcription peaks of genes encoding uptake hydrogenase, key enzymes for carbon fixation, respiratory complexes as well as enzymes for TCA cycle and acetate uptake suggest an aerobic chemomixotrophic lifestyle. This is the first in situ study of the versatile energy metabolism of C. aggregans based on gene transcription patterns. The results provide novel insights into the metabolic flexibility of these filamentous anoxygenic phototrophs that thrive under dynamic environmental conditions.

scholarly journals Changes in Quinone Profiles of Hot Spring Microbial Mats with a Thermal Gradient

1999 ◽  
Vol 65 (1) ◽  
pp. 198-205 ◽  
Author(s):  
Akira Hiraishi ◽  
Taichi Umezawa ◽  
Hiroyuki Yamamoto ◽  
Kenji Kato ◽  
Yonosuke Maki
Keyword(s):  
Thermal Gradient ◽  
Microbial Mats ◽  
Hot Springs ◽  
Hot Spring ◽  
Thermal Gradients ◽  
Cyanobacterial Mats ◽  
Dissimilarity Index ◽  
Quinone Profile ◽  
Bacterial Mats ◽  
Different Temperatures

ABSTRACT The respiratory and photosynthetic quinones of microbial mats which occurred in Japanese sulfide-containing neutral-pH hot springs at different temperatures were analyzed by spectrochromatography and mass spectrometry. All of the microbial mats that developed at high temperatures (temperatures above 68°C) were so-called sulfur-turf bacterial mats and produced methionaquinones (MTKs) as the major quinones. A 78°C hot spring sediment had a similar quinone profile.Chloroflexus-mixed mats occurred at temperatures of 61 to 65°C and contained menaquinone 10 (MK-10) as the major component together with significant amounts of either MTKs or plastoquinone 9 (PQ-9). The sunlight-exposed biomats growing at temperatures of 45 to 56°C were all cyanobacterial mats, in which the photosynthetic quinones (PQ-9 and phylloquinone) predominated and MK-10 was the next most abundant component in most cases. Ubiquinones (UQs) were not found or were detected in only small amounts in the biomats growing at temperatures of 50°C and above, whereas the majority of the quinones of a purple photosynthetic mat growing at 34°C were UQs. A numerical analysis of the quinone profiles was performed by using the following three parameters: dissimilarity index (D), microbial divergence index (MDq ), and bioenergetic divergence index (BDq ). A D matrix tree analysis showed that the hot spring mats consisting of the sulfur-turf bacteria, Chloroflexus spp., cyanobacteria, and purple phototrophic bacteria formed distinct clusters. Analyses ofMDq and BDq values indicated that the microbial diversity of hot spring mats decreased as the temperature of the environment increased. The changes in quinone profiles and physiological types of microbial mats in hot springs with thermal gradients are discussed from evolutionary viewpoints.

scholarly journals Short-Term Stable Isotope Probing of Proteins Reveals Taxa Incorporating Inorganic Carbon in a Hot Spring Microbial Mat

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Laurey Steinke ◽  
Gordon W. Slysz ◽  
Mary S. Lipton ◽  
Christian Klatt ◽  
James J. Moran ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Inorganic Carbon ◽  
Microbial Mats ◽  
Carbon Fixation ◽  
Hot Springs ◽  
Hot Spring ◽  
Stable Isotope Probing ◽  
Short Term ◽  
Low Light ◽  
Assembly Sequences

ABSTRACT The upper green layer of the chlorophototrophic microbial mats associated with the alkaline siliceous hot springs of Yellowstone National Park consists of oxygenic cyanobacteria (Synechococcus spp.), anoxygenic Roseiflexus spp., and several other anoxygenic chlorophototrophs. Synechococcus spp. are believed to be the main fixers of inorganic carbon (Ci), but some evidence suggests that Roseiflexus spp. also contribute to inorganic carbon fixation during low-light, anoxic morning periods. Contributions of other phototrophic taxa have not been investigated. In order to follow the pathway of Ci incorporation into different taxa, mat samples were incubated with [13C]bicarbonate for 3 h during the early-morning, low-light anoxic period. Extracted proteins were treated with trypsin and analyzed by mass spectrometry, leading to peptide identifications and peptide isotopic profile signatures containing evidence of 13C label incorporation. A total of 25,483 peptides, corresponding to 7,221 proteins, were identified from spectral features and associated with mat taxa by comparison to metagenomic assembly sequences. A total of 1,417 peptides, derived from 720 proteins, were detectably labeled with 13C. Most 13C-labeled peptides were derived from proteins of Synechococcus spp. and Roseiflexus spp. Chaperones and proteins of carbohydrate metabolism were most abundantly labeled. Proteins involved in photosynthesis, Ci fixation, and N2 fixation were also labeled in Synechococcus spp. Importantly, most proteins of the 3-hydroxypropionate bi-cycle for Ci fixation in Roseiflexus spp. were labeled, establishing that members of this taxocene contribute to Ci fixation. Other taxa showed much lower [13C]bicarbonate incorporation. IMPORTANCE Yellowstone hot spring mats have been studied as natural models for understanding microbial community ecology and as modern analogs of stromatolites, the earliest community fossils on Earth. Stable-isotope probing of proteins (Pro-SIP) permitted short-term interrogation of the taxa that are involved in the important process of light-driven Ci fixation in this highly active community and will be useful in linking other metabolic processes to mat taxa. Here, evidence is presented that Roseiflexus spp., which use the 3-hydroxypropionate bi-cycle, are active in Ci fixation. Because this pathway imparts a lower degree of selection of isotopically heavy Ci than does the Calvin-Benson-Bassham cycle, the results suggest a mechanism to explain why the natural abundance of 13C in mat biomass is greater than expected if only the latter pathway were involved. Understanding how mat community members influence the 13C/12C ratios of mat biomass will help geochemists interpret the 13C/12C ratios of organic carbon in the fossil record.

scholarly journals Distinct microbial composition and functions in an underground high-temperature hot spring at different depths

2019 ◽  
Author(s):  
Shijie Bai ◽  
Xiaotong Peng
Keyword(s):  
High Temperature ◽  
Microbial Communities ◽  
Hot Springs ◽  
Hot Spring ◽  
Hydrogen Oxidation ◽  
Archaeal Community ◽  
Limited Area ◽  
Rrna Gene ◽  
Microbial Composition ◽  
Different Depths

Abstract. The microbial diversity and functions of three high-temperature neutral hot springs water samples at different depths (0 m, 19 m and 58 m) were investigated based on 16S rRNA gene sequencing and a functional gene array (GeoChip 5.0). The results revealed that the bacterial communities were distinct at different depths in the hot springs. Additionally, in response to the depths, bacterial/archaeal community compositions exhibited shifts over the depth profiles. Aquificae, Alpha-proteobacteria, and Deinococcus-Thermus were the dominating phyla at 0 m, 19 m, and 58 m, respectively. Hydrogenobacter, Sphingobium, and Thermus were the most abundant genera at 0 m, 19 m, and 58 m, respectively. The phylum Thaumarchaeota was the most abundant member of the archaeal community in the samples at different hot spring depths. Functional results of the microbial communities indicated that microbial metabolic functions were mainly related to sulfur, nitrogen cycling, and hydrogen oxidation. In summary, our results demonstrated that distinct microbial communities and functions were found at different depths of hot springs in a very limited area. These findings will provide new insights into the deep-subsurface biosphere associated with terrestrial hot springs.

scholarly journals Characterizing and Evaluating the Diverse Microbial Communities and Their Mercury Resistance Potential from Hot Spring Sites Representing Gradients in Temperature and pH in Yellowstone National Park

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Yelizaveta Rassadkina ◽  
Spencer Roth ◽  
Tamar Barkay
Keyword(s):  
Microbial Communities ◽  
Yellowstone National Park ◽  
National Park ◽  
Hot Springs ◽  
Hot Spring ◽  
Thermophilic Bacteria ◽  
Sequence Data ◽  
Mercury Resistance ◽  
Sample Site ◽  
Microorganism Community

Yellowstone National Park is home to many different hot springs, lakes, geysers, pools, and basins that range in pH, chemical composition, and temperature. These different environmental variations provide a broad range of conditions that select and grow diverse communities of microorganisms. In this study, we collected samples from geochemically diverse lakes and springs to characterize the microbial communities present through 16S rRNA metagenomic analysis. This information was then used to observe how various microorganisms survive in high mercury environments. The results show the presence of microorganisms that have been studied in previous literature. The results also depict gradients of microorganisms including thermophilic bacteria and archaea that exist in these extreme environments. In addition, beta diversity analyses of the sequence data showed site clustering based primarily on temperature instead of pH or sample site, suggesting that while pH, temperature, and sample site were all shown to be significant, temperature is the strongest factor driving microorganism community development. While it is important to characterize the microorganism community present, it is also important to understand how this community functions as a result of its selection. Along with looking at community composition, genomic material was tested to see if it contained mercury methylating (hgcA) or mercury reducing (merA) genes. Out of 22 samples, three of them were observed to have merA genes, while no samples had hgcA genes. These results indicate that microorganisms in Mustard and Nymph Springs may use mercury reduction. Understanding how microorganisms survive in environments with high concentrations of toxic pollutants is crucial because it can be used as a model to better understand mechanisms of resistance and the biogeochemical cycle, as well as for bioremediation and other solutions to anthropogenic problems.

scholarly journals Influence of Sulfide and Temperature on Species Composition and Community Structure of Hot Spring Microbial Mats

2000 ◽  
Vol 66 (7) ◽  
pp. 2835-2841 ◽  
Author(s):  
Sigurlaug Skirnisdottir ◽  
Gudmundur O. Hreggvidsson ◽  
Sigridur Hj�rleifsdottir ◽  
Viggo T. Marteinsson ◽  
Solveig K. Petursdottir ◽  
...  
Keyword(s):  
Microbial Mats ◽  
Hot Springs ◽  
Hot Spring ◽  
Pcr Amplification ◽  
Small Subunit ◽  
Rrna Genes ◽  
Published Data ◽  
Sulfide Concentration ◽  
Small Subunit Rrna ◽  
High Sulfide

ABSTRACT In solfataric fields in southwestern Iceland, neutral and sulfide-rich hot springs are characterized by thick bacterial mats at 60 to 80�C that are white or yellow from precipitated sulfur (sulfur mats). In low-sulfide hot springs in the same area, grey or pink streamers are formed at 80 to 90�C, and a Chloroflexusmat is formed at 65 to 70�C. We have studied the microbial diversity of one sulfur mat (high-sulfide) hot spring and oneChloroflexus mat (low-sulfide) hot spring by cloning and sequencing of small-subunit rRNA genes obtained by PCR amplification from mat DNA. Using 98% sequence identity as a cutoff value, a total of 14 bacterial operational taxonomic units (OTUs) and 5 archaeal OTUs were detected in the sulfur mat; 18 bacterial OTUs were detected in theChloroflexus mat. Although representatives of novel divisions were found, the majority of the sequences were >95% related to currently known sequences. The molecular diversity analysis showed that Chloroflexus was the dominant mat organism in the low-sulfide spring (1 mg liter−1) below 70�C, whereasAquificales were dominant in the high-sulfide spring (12 mg liter−1) at the same temperature. Comparison of the present data to published data indicated that there is a relationship between mat type and composition of Aquificales on the one hand and temperature and sulfide concentration on the other hand.

FeAs2 biomineralization on encrusted bacteria in hot springs: an ecological role of symbiotic bacteria

2003 ◽  
Vol 40 (11) ◽  
pp. 1725-1738 ◽  
Author(s):  
Kazue Tazaki ◽  
Islam ABM Rafiqul ◽  
Kaori Nagai ◽  
Takayuki Kurihara
Keyword(s):  
Metal Binding ◽  
Microbial Mats ◽  
Hot Springs ◽  
Hot Spring ◽  
Binding Potential ◽  
Resistant Bacteria ◽  
X Ray Diffraction ◽  
Ft Ir ◽  
Ir Analysis

Bacterial FeAs2 mineralization was found in the reddish-brown microbial mats that have grown on the walls of the drainage systems of Masutomi Hot Springs, Yamanashi Prefecture, Japan. The reddish-brown microbial mats, which are mainly composed of bacilliform and coccoid types of bacteria, have been analyzed and observed by microtechniques to interpret the bacterial biomineralization and search for the clues to bioremediation. These bacteria accumulate Fe and As along with other trace elements to form various biominerals. The electron diffraction (ED) pattern of the bacterial capsule identified lollingite (FeAs2) and calcite (CaCO3) on the surface of the cell. Based on Fourier-transform infrared absorbance spectroscopy (FT–IR) analysis, the presence of organic components such as C—H, C=O, CNH, –COOH, and N—H in the reddish-brown microbial mats emphasized the metal-binding potential of the bacteria. X-ray diffraction (XRD) data showed the poorly crystalline character of the precipitates, which consist mainly of hydrous iron oxides (2.7 Å (1 Å = 0.1 nm)). The FeAs2 biominerals form by adsorption onto the bacterial cell wall, as demonstrated by microscopic observations and spectroscopic analysis. These showed that bacteria in the reddish-brown microbial mats have the ability to form biominerals with heavy metals and toxic metalloids like As. Particularly significant in hot spring environments is the role of symbiotic and toxic-resistant bacteria, which have the ability to adapt to high As concentrations. Bacterial FeAs2 mineralization might also be considered a mechanism by which toxic As is removed from the aquatic ecosystem. The results provide evidence for detoxification processes and offer clues to possible methods of bioremediation.

scholarly journals Distribution of Acetothermia-dominated microbial communities in alkaline hot springs of Baikal Rift Zone.

2017 ◽  
Author(s):  
Svetlana V. Zaitseva ◽  
Elena V. Lavrentieva ◽  
Aryuna A. Radnagurueva ◽  
Olga A. Baturina ◽  
Marsel R. Kabilov ◽  
...  
Keyword(s):  
Microbial Community ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Microbial Communities ◽  
Hot Springs ◽  
Rift Zone ◽  
Hot Spring ◽  
Baikal Rift Zone ◽  
Rrna Gene ◽  
Acetyl Coa Pathway

Alkaline hot springs are unique extreme habitats resemble the early Earth and present a valuable resource for the discovery of procaryotic community diversity and isolation of the novel thermophilic Bacteria and Archaea. One of the model for the possible origin of biochemistry in alkaline hot springs revealed the acetyl-CoA pathway of CO2 fixation might be the most ancient form of carbon metabolism. Recent phylogenetic studies have suggested that the phylum Acetothermia is one of the deep branches of the Bacteria domain. Firstly Acetothermia (Candidate division OP1) was characterized in a culture independent molecular phylogenetic survey based on the 16S rRNA gene of the sulfide-rich hot spring, Obsidian Pool, a 75 to 95oC hot spring. Two nearly complete genomes of Acetothermia were established based on genome-resolved metagenomic analysis and its capability of implementing acetogenesis through the ancient reductive acetyl-CoA pathway by utilizing CO2 and H2 was revealed. Although genomic, proteomic and metagenomic approaches investigate basic metabolism and potentional energy conservation of uncultivated candidate phyla but ecological roles of these bacteria and general patterns of diversity and community structure stay unclear. General hydrochemical and geological characterization of alkaline thermal springs of the Baikal Rift zone with high silica concentrations and a nitrogen dominated gas phase is provided. Previous microbiogical studies based on culture-dependent methods recovered a large number of bacterial strains from thermal springs located in Baikal Rift zone. We combined microbial communities analysis by using high-throughput 16S rRNA gene sequencing, biogeochemical measurements, sediment mineralogy and physicochemical characteristics to investigate ecosystems of alkaline hot springs located in the Baikal Rift zone. Uncultivated bacteria belonging to the phylum Acetothermia, along with members of the phyla Firmicutes and Proteobacteria, were identified as the dominant group in hydrothermal sediments communities in the alkaline hot springs of Baikal Rift zone. In bottom sediments of the Alla hot spring, about 57% of all classified sequences represent this phylum. Geochemistry of fluids and sample type were strongly correlated with microbial community composition. The Acetothermia exhibited the highest relative abundance in sediment microbial community associated with alkaline thermal fluids enriched in Fe, Zn, Ni, Al and Cr.

scholarly journals THERMOPHILIC ORGANOTROPHIC BACTERIA OF THE GENUS MEIOTHERMUS IN ALKALINE HYDROTHERMS OF PRIBAIKALYE (BURYATIA)

2015 ◽  
Vol 4 (2) ◽  
pp. 30-32
Author(s):  
Valentina Grygoryevna Budagaeva ◽  
Darima Dondokovna Barkhutova
Keyword(s):  
Baikal Region ◽  
Microbial Mats ◽  
Hot Springs ◽  
Heterotrophic Bacteria ◽  
Hot Spring ◽  
Optimal Growth ◽  
Temperature Range ◽  
Hydrolytic Bacteria ◽  
Pure Cultures ◽  
Ph Range

Aerobic, facultative anaerobic hydrolytic bacteria are widespread in the sediments and microbial mats of alkaline hot springs in Baikal region (Buryatia). Typical representatives of hydrolytic bacteria are alkalotermophylic bacilli which are capable of utilizing organic matter in alkaline hot spring waters. Two pure cultures of bacteria growing on acetate, pyruvate and soetone were isolated from the microbial mat of Baikal region thermal springs (Buryatia). These strains were non-sporeforming straight or curved rods that morphologically similar to the representatives of the genus Meiothermus. Bacteria on agar medium formed small smooth pink colonies. Ecophysiological properties of isolates are studied (with respect to temperature and pH). Optimal growth temperature of culture Um-14-2-1 was 450C, the temperature range was 35-600C. The temperature range of strain Al-14-3 was 30-60C, with an optimum 50 C. The pH range of strain Um-14-2-1 is 6.5 to 9.5, the optimum of 8.0. The pH range of strain Al-14-3 is 6.5 to 9.5, the optimum of 8.5. Two thermophilic heterotrophic bacteria are similar to the genus Meiothermus by morphophysiological properties and the ability to thermophile, and are moderate thermophiles.

scholarly journals Phylogenetic Evidence for the Existence of Novel Thermophilic Bacteria in Hot Spring Sulfur-Turf Microbial Mats in Japan

1998 ◽  
Vol 64 (5) ◽  
pp. 1680-1687 ◽  
Author(s):  
Hiroyuki Yamamoto ◽  
Akira Hiraishi ◽  
Kenji Kato ◽  
Hiroshi X. Chiura ◽  
Yonosuke Maki ◽  
...  
Keyword(s):  
16S Rrna ◽  
Microbial Mats ◽  
Hot Springs ◽  
Hot Spring ◽  
Thermophilic Bacteria ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rdna Sequences ◽  
Major Cluster ◽  
The Common

ABSTRACT So-called sulfur-turf microbial mats, which are macroscopic white filaments or bundles consisting of large sausage-shaped bacteria and elemental sulfur particles, occur in sulfide-containing hot springs in Japan. However, no thermophiles from sulfur-turf mats have yet been isolated as cultivable strains. This study was undertaken to determine the phylogenetic positions of the sausage-shaped bacteria in sulfur-turf mats by direct cloning and sequencing of 16S rRNA genes amplified from the bulk DNAs of the mats. Common clones with 16S rDNA sequences with similarity levels of 94.8 to 99% were isolated from sulfur-turf mat samples from two geographically remote hot springs. Phylogenetic analysis showed that the phylotypes of the common clones formed a major cluster with members of theAquifex-Hydrogenobacter complex, which represents the most deeply branching lineage of the domain bacteria. Furthermore, the bacteria of the sulfur-turf mat phylotypes formed a clade distinguishable from that of other members of theAquifex-Hydrogenobacter complex at the order or subclass level. In situ hybridization with clone-specific probes for 16S rRNA revealed that the common phylotype of sulfur-turf mat bacteria is that of the predominant sausage-shaped bacteria.

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