scholarly journals Metagenomic- and cultivation-based exploration of anaerobic chloroform biotransformation in hypersaline sediments as natural source of chloromethanes

2019 ◽  
Author(s):  
Peng Peng ◽  
Yue Lu ◽  
Tom N.P. Bosma ◽  
Ivonne Nijenhuis ◽  
Bart Nijsse ◽  
...  
Keyword(s):  
Salt Lake ◽  
Extreme Environments ◽  
Natural Source ◽  
Hypersaline Lake ◽  
Stable Isotope Labelling ◽  
Hypersaline Lakes ◽  
Metagenome Analysis ◽  
Reductive Dehalogenase ◽  
Enrichment Cultures ◽  
Interdisciplinary Approaches

AbstractChloroform (CF) is an environmental contaminant that can be naturally formed in various environments ranging from forest soils to salt lakes. Here we investigated CF removal potential in sediments obtained from hypersaline lakes in Western Australia. Reductive dechlorination of CF to dichloromethane (DCM) was observed in enrichment cultures derived from sediments of Lake Strawbridge, which has been reported as a natural source of CF. The lack of CF removal in the abiotic control cultures without artificial electron donors indicated that the observed CF removal is a biotic process. Metabolite analysis with 13C labelled CF in the sediment-free enrichment cultures (pH 8.5, salinity 5%) revealed that increasing the vitamin B12 concentration from 0.04 to 4 μM enhanced CF removal, reduced DCM formation, and increased 13CO2 production, which is likely a product of CF oxidation. Known organohalide-respiring bacteria and reductive dehalogenase genes were neither detected by quantitative PCR nor metagenomic analysis. Rather, members of the order Clostridiales, known to co-metabolically transform CF to DCM and CO2, were detected in the enrichment cultures. Genome-resolved metagenome analysis indicated that their genomes encode enzymatic repertoires for the Wood-Ljungdahl pathway and cobalamin biosynthesis that are known to be involved in co-metabolic CF transformation.ImportanceMore than 90% of the global CF emission to the atmosphere originates from natural sources, including saline environments such as salt lake sediments. However, knowledge about the microbial metabolism of CF in such extreme environments is lacking. Here we showed CF transformation potential in a hypersaline lake that was reported as a natural source of CF production. Application of interdisciplinary approaches of microbial cultivation, stable isotope labelling, and metagenomics aided in defining potential chloroform transformation pathways. This study indicates that microbiota may act as a filter to reduce CF emission from hypersaline lakes to the atmosphere, and expands our knowledge of halogen cycling in extreme hypersaline environments.

scholarly journals Metagenomic- and Cultivation-Based Exploration of Anaerobic Chloroform Biotransformation in Hypersaline Sediments as Natural Source of Chloromethanes

2020 ◽  
Vol 8 (5) ◽  
pp. 665
Author(s):  
Peng Peng ◽  
Yue Lu ◽  
Tom N.P. Bosma ◽  
Ivonne Nijenhuis ◽  
Bart Nijsse ◽  
...  
Keyword(s):  
Vitamin B12 ◽  
Reductive Dechlorination ◽  
Electron Donors ◽  
Natural Source ◽  
Hypersaline Lake ◽  
Reductive Dehalogenase ◽  
Enrichment Cultures ◽  
Cobalamin Biosynthesis ◽  
Abiotic Control ◽  
Hypersaline Sediments

Chloroform (CF) is an environmental contaminant that can be naturally formed in various environments ranging from forest soils to salt lakes. Here we investigated CF removal potential in sediments obtained from hypersaline lakes in Western Australia. Reductive dechlorination of CF to dichloromethane (DCM) was observed in enrichment cultures derived from sediments of Lake Strawbridge, which has been reported as a natural source of CF. No CF removal was observed in abiotic control cultures without artificial electron donors, indicating biotic CF dechlorination in the enrichment cultures. Increasing vitamin B12 concentration from 0.04 to 4 µM in enrichment cultures enhanced CF removal and reduced DCM formation. In cultures amended with 4 µM vitamin B12 and 13C labelled CF, formation of 13CO2 was detected. Known organohalide-respiring bacteria and reductive dehalogenase genes were neither detected using quantitative PCR nor metagenomic analysis of the enrichment cultures. Rather, members of the order Clostridiales, known to co-metabolically transform CF to DCM and CO2, were detected. Accordingly, metagenome-assembled genomes of Clostridiales encoded enzymatic repertoires for the Wood-Ljungdahl pathway and cobalamin biosynthesis, which are known to be involved in fortuitous and nonspecific CF transformation. This study indicates that hypersaline lake microbiomes may act as a filter to reduce CF emission to the atmosphere.

scholarly journals Microbial community structure and diversity within hypersaline Keke Salt Lake environments

2017 ◽  
Vol 63 (11) ◽  
pp. 895-908 ◽  
Author(s):  
Rui Han ◽  
Xin Zhang ◽  
Jing Liu ◽  
Qifu Long ◽  
Laisheng Chen ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Microbial Community Structure ◽  
High Throughput Sequencing ◽  
Salt Lake ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Tibet Plateau ◽  
Hypersaline Lake ◽  
Hypersaline Lakes

Keke Salt Lake is located in the Qaidamu Basin of China. It is a unique magnesium sulfate-subtype hypersaline lake that exhibits a halite domain ecosystem, yet its microbial diversity has remained unstudied. Here, the microbial community structure and diversity was investigated via high-throughput sequencing of the V3–V5 regions of 16S rRNA genes. A high diversity of operational taxonomic units was detected for Bacteria and Archaea (734 and 747, respectively), comprising 21 phyla, 43 classes, and 201 genera of Bacteria and 4 phyla, 4 classes, and 39 genera of Archaea. Salt-saturated samples were dominated by the bacterial genera Bacillus (51.52%–58.35% relative abundance), Lactococcus (9.52%–10.51%), and Oceanobacillus (8.82%–9.88%) within the Firmicutes phylum (74.81%–80.99%), contrasting with other hypersaline lakes. The dominant Archaea belonged to the Halobacteriaceae family, and in particular, the genera (with an abundance of >10% of communities) Halonotius, Halorubellus, Halapricum, Halorubrum, and Natronomonas. Additionally, we report the presence of Nanohaloarchaeota and Woesearchaeota in Qinghai–Tibet Plateau lakes, which has not been previously documented. Total salinity (especially Mg2+, Cl–, Na+, and K+) mostly correlated with taxonomic distribution across samples. These results expand our understanding of microbial resource utilization within hypersaline lakes and the potential adaptations of dominant microorganisms that allow them to inhabit such environments.

scholarly journals Exploring Microbial Resource of Different Rhizocompartments of Dominant Plants Along the Salinity Gradient Around the Hypersaline Lake Ejinur

2021 ◽  
Vol 12 ◽  
Author(s):  
Junqing Luo ◽  
Zhechao Zhang ◽  
Yazhou Hou ◽  
Fengwei Diao ◽  
Baihui Hao ◽  
...  
Keyword(s):  
High Throughput Sequencing ◽  
Salt Lake ◽  
Salinity Gradient ◽  
Salt Lakes ◽  
Hypersaline Environment ◽  
Hypersaline Lake ◽  
Littoral Zones ◽  
Microbial Resources ◽  
Bacteria And Fungi

Lake littoral zones can also be regarded as another extremely hypersaline environment due to hypersaline properties of salt lakes. In this study, high-throughput sequencing technique was used to analyze bacteria and fungi from different rhizocompartments (rhizosphere and endosphere) of four dominant plants along the salinity gradient in the littoral zones of Ejinur Salt Lake. The study found that microbial α-diversity did not increase with the decrease of salinity, indicating that salinity was not the main factor on the effect of microbial diversity. Distance-based redundancy analysis and regression analysis were used to further reveal the relationship between microorganisms from different rhizocompartments and plant species and soil physicochemical properties. Bacteria and fungi in the rhizosphere and endosphere were the most significantly affected by SO42–, SOC, HCO3–, and SOC, respectively. Correlation network analysis revealed the potential role of microorganisms in different root compartments on the regulation of salt stress through synergistic and antagonistic interactions. LEfSe analysis further indicated that dominant microbial taxa in different rhizocompartments had a positive response to plants, such as Marinobacter, Palleronia, Arthrobacter, and Penicillium. This study was of great significance and practical value for understanding salt environments around salt lakes to excavate the potential microbial resources.

scholarly journals The Effects of Artemia Cyst Harvesting on the Salt Lake Ecosystem

2020 ◽  
pp. 348-357
Author(s):  
Liudmila I. Litvinenko ◽  
Aleksander I. Litvinenko ◽  
Elena G. Boyko ◽  
Kirill V. Kutsanov ◽  
Marina A. Korentovich
Keyword(s):  
Salt Lake ◽  
Lake Ecosystem ◽  
Hypersaline Lake ◽  
Daily Production ◽  
Artemia Cyst ◽  
Main Components ◽  
Artemia Cysts ◽  
Artemia Population ◽  
B Coefficients

In Russia, the main stocks of Artemia cysts and cyst harvesting activities are concentrated in Western Siberia. About 1,100 tons of cysts are harvested annually, including 180 tons in the Kurgan Region and 140 tons from Medvezhye Lake (about 2 % of their world harvest). The purpose of this study was to determine the degree of influence of Artemia cyst harvesting on the ecosystem of a salt lake in a case study of Medvezhye Lake. The main trophic components of the ecosystem – phytoplankton, zooplankton, and zoobenthos – were analyzed. The salinity of the brine of Medvezhye Lake varied between 110 and 320 g/dm3 in different years. Phytoplankton in the lake function throughout the year. They are characterized by small cell sizes, low biomass (0.76±0.24 mg/L) and daily production (1.03±0.18 mgO2/L or 0.3±0.05 gC/m2), and high levels of A/B and P/B coefficients. Zooplankton and zoobenthos are represented mainly by Artemia. The biomass of Artemia shrimp reached 21.9±3.2 mg/L (219 kg/ha) on average during 1995-2018. During this period, the stock of cysts formed annually in the lake was 114.5±14.3 kg/ha; the harvest was 23.7±3.0 kg/ha (21 % of the stock). The main components of the ecosystem – phytoplankton – Artemia shrimp – Artemia cysts – were produced annually in the following proportions: 8390:2678:115 kg/ha·year (75:24:1 %). The removal of 23.7 kg/ha of the cysts (0.22 % of the production of all components) from the lake is negligible compared to the other components of the ecosystem. The residual density of cysts after harvesting, which is necessary for the reproduction of the Artemia population for the next season during the 1st generation, is 10 kg/ha. Averaged data indicate that the amount of Artemia cysts left in the ecosystem of Medvezhye Lake after cyst harvesting is 91 kg/ha, i.e. 9 times greater than the minimum required density. The results reported in the present study indicate that the current level of cyst harvesting cannot have any significant impact on the ecosystem of the hypersaline lake

scholarly journals Contributions of Lake-Effect Periods to the Cool-Season Hydroclimate of the Great Salt Lake Basin

2013 ◽  
Vol 52 (2) ◽  
pp. 341-362 ◽  
Author(s):  
Kristen N. Yeager ◽  
W. James Steenburgh ◽  
Trevor I. Alcott
Keyword(s):  
Snow Water Equivalent ◽  
Salt Lake ◽  
Great Salt Lake ◽  
Hypersaline Lake ◽  
Lake Basin ◽  
Cool Season ◽  
Lake Effect ◽  
Precipitation Estimates ◽  
Radar Imagery ◽  
Precipitation Gauge

AbstractAlthough smaller lakes are known to produce lake-effect precipitation, their influence on the precipitation climatology of lake-effect regions remains poorly documented. This study examines the contribution of lake-effect periods (LEPs) to the 1998–2009 cool-season (16 September–15 May) hydroclimate in the region surrounding the Great Salt Lake, a meso-β-scale hypersaline lake in northern Utah. LEPs are identified subjectively from radar imagery, with precipitation (snow water equivalent) quantified through the disaggregation of daily (i.e., 24 h) Cooperative Observer Program (COOP) and Snowpack Telemetry (SNOTEL) observations using radar-derived precipitation estimates. An evaluation at valley and mountain stations with reliable hourly precipitation gauge observations demonstrates that the disaggregation method works well for estimating precipitation during LEPs. During the study period, LEPs account for up to 8.4% of the total cool-season precipitation in the Great Salt Lake basin, with the largest contribution to the south and east of the Great Salt Lake. The mean monthly distribution of LEP precipitation is bimodal, with a primary maximum from October to November and a secondary maximum from March to April. LEP precipitation is highly variable between cool seasons and is strongly influenced by a small number of intense events. For example, at a lowland (mountain) station in the lake-effect-precipitation belt southeast of the Great Salt Lake, just 12 (13) events produce 50% of the LEP precipitation. Although these results suggest that LEPs contribute modestly to the hydroclimate of the Great Salt Lake basin, infrequent but intense events have a profound impact during some cool seasons.

scholarly journals Cultivation of Mesophilic Soil Crenarchaeotes in Enrichment Cultures from Plant Roots

2005 ◽  
Vol 71 (8) ◽  
pp. 4751-4760 ◽  
Author(s):  
Holly M. Simon ◽  
Courtney E. Jahn ◽  
Luke T. Bergerud ◽  
Marek K. Sliwinski ◽  
Paul J. Weimer ◽  
...  
Keyword(s):  
Extreme Environments ◽  
Single Strand Conformation Polymorphism ◽  
Plant Roots ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Root Extract ◽  
Enrichment Cultures ◽  
Molecular Phylogenetic ◽  
Terrestrial Habitats

ABSTRACT Because archaea are generally associated with extreme environments, detection of nonthermophilic members belonging to the archaeal division Crenarchaeota over the last decade was unexpected; they are surprisingly ubiquitous and abundant in nonextreme marine and terrestrial habitats. Metabolic characterization of these nonthermophilic crenarchaeotes has been impeded by their intractability toward isolation and growth in culture. From studies employing a combination of cultivation and molecular phylogenetic techniques (PCR-single-strand conformation polymorphism, sequence analysis of 16S rRNA genes, fluorescence in situ hybridization, and real-time PCR), we present evidence here that one of the two dominant phylotypes of Crenarchaeota that colonizes the roots of tomato plants grown in soil from a Wisconsin field is selectively enriched in mixed cultures amended with root extract. Clones recovered from enrichment cultures were found to group phylogenetically with sequences from clade C1b.A1. This work corroborates and extends our recent findings, indicating that the diversity of the crenarchaeal soil assemblage is influenced by the rhizosphere and that mesophilic soil crenarchaeotes are found associated with plant roots, and provides the first evidence for growth of nonthermophilic crenarchaeotes in culture.

scholarly journals Natrialba swarupiae sp. nov., a halophilic archaeon isolated from a hypersaline lake in India

2020 ◽  
Vol 70 (3) ◽  
pp. 1876-1881 ◽  
Author(s):  
Swapnil Kajale ◽  
Neelima Deshpande ◽  
Snigdha Pali ◽  
Yogesh Shouche ◽  
Avinash Sharma
Keyword(s):  
Type Species ◽  
Salt Lake ◽  
Methyl Esters ◽  
Hypersaline Lake ◽  
Rrna Gene ◽  
Content Type ◽  
Link Type ◽  
A Genome ◽  
Salt Pan ◽  
Natrialba Magadii

A haloarchaeal strain (ESP3B_9T) was isolated from the salt pan of Sambhar salt lake, Rajasthan, India. Cells were coccoid, non-motile, Gram-stain-negative and formed reddish-pink pigmented colonies. The strain was aerobic, able to grow at 35–55 °C (optimum, 40 °C), in 20–35 % (25 %) NaCl and pH 8–10 (pH 9). Mg2+ not required for growth. The cells were lysed in distilled water and the minimum NaCl concentration that prevented cell lysis was 5 % w/v. The 16S rRNA gene sequence similarities between strain ESP3B_9T and Natrialba hulunbeirensis JCM 10989T and Natrialba magadii ATCC 43099T were 96.53 and 96.25 % respectively. The similarities of the RNA polymerase subunit B gene between strain ESP3B_9T and N. hulunbeirensis JCM 10989T and N. magadii ATCC 43099T were 84.47 and 84.9 % respectively. Genome sequencing revealed a genome size of 4.20 Mbp with DNA G+C content of 62.5 mol%. The major polar lipids were phosphotidylglycerol and phosphatidylglycerol phosphate methyl esters with minor amounts of unidentified lipids. The results of polyphasic analysis determined that strain ESP3B_9T represents a novel species of the genus Natrialba , for which the name Natrialba swarupiae sp. nov. is proposed. The type strain is ESP3B_9T (MCC 3419T=JCM 33002T=KCTC 4279T=CGMCC 1.16737T).

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