scholarly journals Transparent soil microcosms for live-cell imaging and non-destructive stable isotope probing of soil microorganisms

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Kriti Sharma ◽  
Márton Palatinszky ◽  
Georgi Nikolov ◽  
David Berry ◽  
Elizabeth A Shank
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Probing ◽  
Three Dimensions ◽  
Bacterial Survival ◽  
Soil Microcosms ◽  
Transparent Soil ◽  
Dry Down ◽  
Destructive Measurement ◽  
The Impact ◽  
Non Destructive

Microscale processes are critically important to soil ecology and biogeochemistry yet are difficult to study due to soil’s opacity and complexity. To advance the study of soil processes, we constructed transparent soil microcosms that enable the visualization of microbes via fluorescence microscopy and the non-destructive measurement of microbial activity and carbon uptake in situ via Raman microspectroscopy. We assessed the polymer Nafion and the crystal cryolite as optically transparent soil substrates. We demonstrated that both substrates enable the growth, maintenance, and visualization of microbial cells in three dimensions over time, and are compatible with stable isotope probing using Raman. We applied this system to ascertain that after a dry-down/rewetting cycle, bacteria on and near dead fungal hyphae were more metabolically active than those far from hyphae. These data underscore the impact fungi have facilitating bacterial survival in fluctuating conditions and how these microcosms can yield insights into microscale microbial activities.

scholarly journals Identification of Benzo[a]pyrene-Metabolizing Bacteria in Forest Soils by Using DNA-Based Stable-Isotope Probing

2015 ◽  
Vol 81 (21) ◽  
pp. 7368-7376 ◽  
Author(s):  
Mengke Song ◽  
Chunling Luo ◽  
Longfei Jiang ◽  
Dayi Zhang ◽  
Yujie Wang ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Forest Soils ◽  
Contaminated Soils ◽  
Stable Isotope Probing ◽  
Soil Microcosms ◽  
Content Type ◽  
The Family ◽  
Polycyclic Aromatic ◽  
Uncultivated Bacteria ◽  
Different Soils

ABSTRACTDNA-based stable-isotope probing (DNA-SIP) was used in this study to investigate the uncultivated bacteria with benzo[a]pyrene (BaP) metabolism capacities in two Chinese forest soils (Mt. Maoer in Heilongjiang Province and Mt. Baicaowa in Hubei Province). We characterized three different phylotypes with responsibility for BaP degradation, none of which were previously reported as BaP-degrading microorganisms by SIP. In Mt. Maoer soil microcosms, the putative BaP degraders were classified as belonging to the genusTerrimonas(familyChitinophagaceae, orderSphingobacteriales), whereasBurkholderiaspp. were the key BaP degraders in Mt. Baicaowa soils. The addition of metabolic salicylate significantly increased BaP degradation efficiency in Mt. Maoer soils, and the BaP-metabolizing bacteria shifted to the microorganisms in the familyOxalobacteraceae(genus unclassified). Meanwhile, salicylate addition did not change either BaP degradation or putative BaP degraders in Mt. Baicaowa. Polycyclic aromatic hydrocarbon ring-hydroxylating dioxygenase (PAH-RHD) genes were amplified, sequenced, and quantified in the DNA-SIP13C heavy fraction to further confirm the BaP metabolism. By illuminating the microbial diversity and salicylate additive effects on BaP degradation across different soils, the results increased our understanding of BaP natural attenuation and provided a possible approach to enhance the bioremediation of BaP-contaminated soils.

scholarly journals Investigation of an Acetate-Fed Denitrifying Microbial Community by Stable Isotope Probing, Full-Cycle rRNA Analysis, and Fluorescent In Situ Hybridization-Microautoradiography

2005 ◽  
Vol 71 (12) ◽  
pp. 8683-8691 ◽  
Author(s):  
Maneesha P. Ginige ◽  
Jürg Keller ◽  
Linda L. Blackall
Keyword(s):  
In Situ Hybridization ◽  
Stable Isotope ◽  
Activated Sludge ◽  
Fluorescent In Situ Hybridization ◽  
Batch Reactor ◽  
External Source ◽  
Stable Isotope Probing ◽  
Rrna Gene ◽  
The Impact

ABSTRACT The acetate-utilizing microbial consortium in a full-scale activated sludge process was investigated without prior enrichment using stable isotope probing (SIP). [13C]acetate was used in SIP to label the DNA of the denitrifiers. The [13C]DNA fraction that was extracted was subjected to a full-cycle rRNA analysis. The dominant 16S rRNA gene phylotypes in the 13C library were closely related to the bacterial families Comamonadaceae and Rhodocyclaceae in the class Betaproteobacteria. Seven oligonucleotide probes for use in fluorescent in situ hybridization (FISH) were designed to specifically target these clones. Application of these probes to the sludge of a continuously fed denitrifying sequencing batch reactor (CFDSBR) operated for 16 days revealed that there was a significant positive correlation between the CFDSBR denitrification rate and the relative abundance of all probe-targeted bacteria in the CFDSBR community. FISH-microautoradiography demonstrated that the DEN581 and DEN124 probe-targeted cells that dominated the CFDSBR were capable of taking up [14C]acetate under anoxic conditions. Initially, DEN444 and DEN1454 probe-targeted bacteria also dominated the CFDSBR biomass, but eventually DEN581 and DEN124 probe-targeted bacteria were the dominant bacterial groups. All probe-targeted bacteria assessed in this study were denitrifiers capable of utilizing acetate as a source of carbon. The rapid increase in the number of organisms positively correlated with the immediate increase in denitrification rates observed by plant operators when acetate is used as an external source of carbon to enhance denitrification. We suggest that the impact of bacteria on activated sludge subjected to intermittent acetate supplementation should be assessed prior to the widespread use of acetate in the wastewater industry to enhance denitrification.

scholarly journals Quantification of archaea-driven freshwater nitrification: from single cell to ecosystem level

2021 ◽  
Author(s):  
Franziska Klotz ◽  
Katharina Kitzinger ◽  
David Kamanda Ngugi ◽  
Petra Buesing ◽  
Sten Littmann ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Average Rate ◽  
Stable Isotope Probing ◽  
Lake Constance ◽  
Phylogenomic Analysis ◽  
Oligotrophic Lakes ◽  
Ammonia Oxidizing Archaea ◽  
Activity Measurements ◽  
Ecosystem Level ◽  
The Impact

Deep oligotrophic lakes sustain large archaeal populations of the class Nitrososphaeria in their hypolimnion. They are thought to be the key ammonia oxidizers in these freshwater systems and as such responsible for the rate-limiting step in nitrification. However, the impact that planktonic Nitrososphaeria have on N cycling in lakes is severely understudied and yet to be quantified. Here, we followed this archaeal population in one of Central Europe's largest lakes, Lake Constance, over two consecutive years using metagenomics and metatranscriptomics combined with stable isotope-based activity measurements. A single, highly abundant and transcriptionally active freshwater ecotype of Nitrososphaeria dominated the nitrifying community. Phylogenomic analysis of its metagenome-assembled genome showed that this ecotype represents a new lacustrine Nitrosopumilus species. Stable isotope probing revealed that Nitrososphaeria incorporated significantly more 15N-labeled ammonium than most other microorganisms at near-natural conditions and oxidized ammonia at an average rate of 0.22 ± 0.11 fmol cell-1 d-1. This translates to 1.9 gigagram of ammonia oxidized per year, corresponding to 12% of the N-biomass produced annually by photosynthetic organisms in Lake Constance. Here, we show that ammonia-oxidizing archaea play an equally important role in the nitrogen cycle of deep oligotrophic lakes as their counterparts in marine ecosystems.

scholarly journals Phylogeny of Acetate-Utilizing Microorganisms in Soils along a Nutrient Gradient in the Florida Everglades

2006 ◽  
Vol 72 (10) ◽  
pp. 6837-6840 ◽  
Author(s):  
Ashvini Chauhan ◽  
Andrew Ogram
Keyword(s):  
Stable Isotope ◽  
16S Rrna ◽  
Stable Isotope Probing ◽  
Florida Everglades ◽  
Gene Clone ◽  
Rrna Gene ◽  
Acetate Oxidation ◽  
Soil Microcosms ◽  
Nutrient Gradient ◽  
Syntrophic Acetate Oxidation

ABSTRACT The consumption of acetate in soils taken from a nutrient gradient in the northern Florida Everglades was studied by stable isotope probing. Bacterial and archaeal 16S rRNA gene clone libraries from eutrophic and oligotrophic soil microcosms strongly suggest that a significant amount of acetate is consumed by syntrophic acetate oxidation in nutrient-enriched soil.

Stable Isotope Probing Identifies Novel m-Xylene Degraders in Soil Microcosms from Contaminated and Uncontaminated Sites

2010 ◽  
Vol 212 (1-4) ◽  
pp. 113-122 ◽  
Author(s):  
Shuguang Xie ◽  
Weimin Sun ◽  
Chunling Luo ◽  
Alison M. Cupples
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Probing ◽  
Soil Microcosms
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