scholarly journals DNA stable isotope probing reveals contrasted activity and phenanthrene-degrading bacteria identity in a gradient of anthropized soils

2019 ◽  
Vol 95 (12) ◽  
Author(s):  
Florian Lemmel ◽  
Florence Maunoury-Danger ◽  
Corinne Leyval ◽  
Aurélie Cébron

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous soil organic pollutants. Although PAH-degrading bacteria are present in almost all soils, their selection and enrichment have been shown in historically high PAH contaminated soils. We can wonder if the effectiveness of PAH biodegradation and the PAH-degrading bacterial diversity differ among soils. The stable isotope probing (SIP) technique with 13C-phenanthrene (PHE) as a model PAH was used to: (i) compare for the first time a range of 10 soils with various PAH contamination levels, (ii) determine their PHE-degradation efficiency and (iii) identify the active PHE-degraders using 16S rRNA gene amplicon sequencing from 13C-labeled DNA. Surprisingly, the PHE degradation rate was not directly correlated to the initial level of total PAHs and phenanthrene in the soils, but was mostly explained by the initial abundance and richness of soil bacterial communities. A large diversity of PAH-degrading bacteria was identified for seven of the soils, with differences among soils. In the soils where the PHE degradation activities were the higher, Mycobacterium species were always the dominant active PHE degraders. A positive correlation between PHE-degradation level and the diversity of active PHE-degraders (Shannon index) supported the hypothesis that cooperation between strains led to a more efficient PAH degradation.

2011 ◽  
Vol 77 (21) ◽  
pp. 7856-7860 ◽  
Author(s):  
Tony Gutierrez ◽  
David R. Singleton ◽  
Michael D. Aitken ◽  
Kirk T. Semple

ABSTRACTPolycyclic aromatic hydrocarbon (PAH)-degrading bacteria associated with an algal bloom in Tampa Bay, FL, were investigated by stable isotope probing (SIP) with uniformly labeled [13C]naphthalene. The dominant sequences in clone libraries constructed from13C-enriched bacterial DNA (from naphthalene enrichments) were identified as uncharacterized members of the familyRhodobacteraceae. Quantitative PCR primers targeting the 16S rRNA gene of these uncultivated organisms were used to determine their abundance in incubations amended with unlabeled naphthalene and phenanthrene, both of which showed substantial increases in gene copy numbers during the experiments. As demonstrated by this work, the application of uniformly13C-labeled PAHs in SIP experiments can successfully be used to identify novel PAH-degrading bacteria in marine waters.


2015 ◽  
Vol 81 (21) ◽  
pp. 7368-7376 ◽  
Author(s):  
Mengke Song ◽  
Chunling Luo ◽  
Longfei Jiang ◽  
Dayi Zhang ◽  
Yujie Wang ◽  
...  

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.


2019 ◽  
Author(s):  
Ella T. Sieradzki ◽  
Michael Morando ◽  
Jed A. Fuhrman

AbstractBacterial biodegradation is a significant contributor to remineralization of polycyclic aromatic hydrocarbons (PAHs): toxic and recalcitrant components of crude oil as well as byproducts of partial combustion chronically introduced into seawater via atmospheric deposition. The Deepwater Horizon oil spill demonstrated the speed at which a seed PAH-degrading community maintained by low chronic inputs can respond to an acute pollution. We investigated the diversity and functional potential of a similar seed community in the Port of Los Angeles, a chronically polluted site, using stable isotope probing with naphthalene, deep-sequenced metagenomes and carbon incorporation rate measurements at the port and in two sites further into the San Pedro Channel. We show a switch in the composition of the PAH degrading community from diverse early-responding generalists to late-blooming specialized degraders. This switch demonstrates the ability of the local seed community of degraders at the Port of LA to incorporate carbon from PAHs independently of a labile-hydrocarbon degrading succession. We were able to directly show that assembled genomes belonged to naphthalene degraders by matching their 16S-rRNA gene with experimental stable isotope probing data. Surprisingly, we did not find a full PAH degradation pathway in any of those genomes and even when combining genes from the entire microbial community. We use metabolic pathways identified in those genomes to generate metagenomic-based recommendations for future optimization of PAHs bioremediation.


2015 ◽  
Vol 81 (14) ◽  
pp. 4607-4615 ◽  
Author(s):  
Xiaoqing Wang ◽  
Christine E. Sharp ◽  
Gareth M. Jones ◽  
Stephen E. Grasby ◽  
Allyson L. Brady ◽  
...  

ABSTRACTThe exopolysaccharides (EPSs) produced by some bacteria are potential growth substrates for other bacteria in soil. We used stable-isotope probing (SIP) to identify aerobic soil bacteria that assimilated the cellulose produced byGluconacetobacter xylinusor the EPS produced byBeijerinckia indica. The latter is a heteropolysaccharide comprised primarily ofl-guluronic acid,d-glucose, andd-glycero-d-mannoheptose.13C-labeled EPS and13C-labeled cellulose were purified from bacterial cultures grown on [13C]glucose. Two soils were incubated with these substrates, and bacteria actively assimilating them were identified via pyrosequencing of 16S rRNA genes recovered from13C-labeled DNA. Cellulose C was assimilated primarily by soil bacteria closely related (93 to 100% 16S rRNA gene sequence identities) to known cellulose-degrading bacteria. However,B. indicaEPS was assimilated primarily by bacteria with low identities (80 to 95%) to known species, particularly by different members of the phylumPlanctomycetes. In one incubation, members of thePlanctomycetesmade up >60% of all reads in the labeled DNA and were only distantly related (<85% identity) to any described species. Although it is impossible with SIP to completely distinguish primary polysaccharide hydrolyzers from bacteria growing on produced oligo- or monosaccharides, the predominance ofPlanctomycetessuggested that they were primary degraders of EPS. Other bacteria assimilatingB. indicaEPS included members of theVerrucomicrobia, candidate division OD1, and theArmatimonadetes. The results indicate that some uncultured bacteria in soils may be adapted to using complex heteropolysaccharides for growth and suggest that the use of these substrates may provide a means for culturing new species.


mSystems ◽  
2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Ella T. Sieradzki ◽  
Michael Morando ◽  
Jed A. Fuhrman

ABSTRACT Bacterial biodegradation is a significant contributor to remineralization of polycyclic aromatic hydrocarbons (PAHs)—toxic and recalcitrant components of crude oil as well as by-products of partial combustion chronically introduced into seawater via atmospheric deposition. The Deepwater Horizon oil spill demonstrated the speed at which a seed PAH-degrading community maintained by chronic inputs responds to acute pollution. We investigated the diversity and functional potential of a similar seed community in the chronically polluted Port of Los Angeles (POLA), using stable isotope probing with naphthalene, deep-sequenced metagenomes, and carbon incorporation rate measurements at the port and in two sites in the San Pedro Channel. We demonstrate the ability of the community of degraders at the POLA to incorporate carbon from naphthalene, leading to a quick shift in microbial community composition to be dominated by the normally rare Colwellia and Cycloclasticus. We show that metagenome-assembled genomes (MAGs) belonged to these naphthalene degraders by matching their 16S-rRNA gene with experimental stable isotope probing data. Surprisingly, we did not find a full PAH degradation pathway in those genomes, even when combining genes from the entire microbial community, leading us to hypothesize that promiscuous dehydrogenases replace canonical naphthalene degradation enzymes in this site. We compared metabolic pathways identified in 29 genomes whose abundance increased in the presence of naphthalene to generate genomic-based recommendations for future optimization of PAH bioremediation at the POLA, e.g., ammonium as opposed to urea, heme or hemoproteins as an iron source, and polar amino acids. IMPORTANCE Oil spills in the marine environment have a devastating effect on marine life and biogeochemical cycles through bioaccumulation of toxic hydrocarbons and oxygen depletion by hydrocarbon-degrading bacteria. Oil-degrading bacteria occur naturally in the ocean, especially where they are supported by chronic inputs of oil or other organic carbon sources, and have a significant role in degradation of oil spills. Polycyclic aromatic hydrocarbons are the most persistent and toxic component of crude oil. Therefore, the bacteria that can break those molecules down are of particular importance. We identified such bacteria at the Port of Los Angeles (POLA), one of the busiest ports worldwide, and characterized their metabolic capabilities. We propose chemical targets based on those analyses to stimulate the activity of these bacteria in case of an oil spill in the Port POLA.


2006 ◽  
Vol 72 (5) ◽  
pp. 3586-3592 ◽  
Author(s):  
Yuki Kasai ◽  
Yoh Takahata ◽  
Mike Manefield ◽  
Kazuya Watanabe

ABSTRACT Stable isotope probing (SIP) of benzene-degrading bacteria in gasoline-contaminated groundwater was coupled to denaturing gradient gel electrophoresis (DGGE) of DNA fragments amplified by reverse transcription-PCR from community 16S rRNA molecules. Supplementation of the groundwater with [13C6]benzene together with an electron acceptor (nitrate, sulfate, or oxygen) showed that a phylotype affiliated with the genus Azoarcus specifically appeared in the 13C-RNA fraction only when nitrate was supplemented. This phylotype was also observed as the major band in DGGE analysis of bacterial 16S rRNA gene fragments amplified by PCR from the gasoline-contaminated groundwater. In order to isolate the Azoarcus strains, the groundwater sample was streaked on agar plates containing nonselective diluted CGY medium, and the DGGE analysis was used to screen colonies formed on the plates. This procedure identified five bacterial isolates (from 60 colonies) that corresponded to the SIP-identified Azoarcus phylotype, among which two strains (designated DN11 and AN9) degraded benzene under denitrifying conditions. Incubation of these strains with [14C]benzene showed that the labeled carbon was mostly incorporated into 14CO2 within 14 days. These results indicate that the Azoarcus population was involved in benzene degradation in the gasoline-contaminated groundwater under denitrifying conditions. We suggest that RNA-based SIP identification coupled to phylogenetic screening of nonselective isolates facilitates the isolation of enrichment/isolation-resistant microorganisms with a specific function.


2019 ◽  
Vol 85 (14) ◽  
Author(s):  
Jibing Li ◽  
Chunling Luo ◽  
Dayi Zhang ◽  
Xixi Cai ◽  
Longfei Jiang ◽  
...  

ABSTRACTTo identify and obtain the indigenous degraders metabolizing phenanthrene (PHE) and biphenyl (BP) from the complex microbial community within industrial wastewater, DNA-based stable-isotope probing (DNA-SIP) and cultivation-based methods were applied in the present study. DNA-SIP results showed that two bacterial taxa (VogesellaandAlicyclobacillus) were considered the key biodegraders responsible for PHE biodegradation only, whereasBacillusandCupriaviduswere involved in BP degradation.VogesellaandAlicyclobacillushave not been linked with PHE degradation previously. Additionally, DNA-SIP helped reveal the taxonomic identity ofRalstonia-like degraders involved in both PHE and BP degradation. To target the separation of functionalRalstonia-like degraders from the wastewater, we modified the traditional cultivation medium and culture conditions. Finally, an indigenous PHE- and BP-degrading strain,Ralstonia pickettiiM1, was isolated via a cultivation-dependent method, and its role in PHE and BP degradation was confirmed by enrichment of the 16S rRNA gene and distinctive dioxygenase genes in the DNA-SIP experiment. Our study has successfully established a program for the application of DNA-SIP in the isolation of the active functional degraders from an environment. It also deepens our insight into the diversity of indigenous PHE- and BP-degrading communities.IMPORTANCEThe comprehensive treatment of wastewater in industrial parks suffers from the presence of multiple persistent organic pollutants (POPs), such as polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs), which reduce the activity of activated sludge and are difficult to eliminate. Characterizing and applying active bacterial degraders metabolizing multiple POPs therefore helps to reveal the mechanisms of synergistic metabolism and to improve wastewater treatment efficiency in industrial parks. To date, SIP studies have successfully investigated the biodegradation of PAHs or PCBs in real-world habitats. DNA-SIP facilitates the isolation of target microorganisms that pose environmental concerns. Here, an indigenous phenanthrene (PHE)- and biphenyl (BP)-degrading strain in wastewater,Ralstonia pickettiiM1, was isolated via a cultivation-dependent method, and its role in PHE and BP degradation was confirmed by DNA-SIP. Our study provides a routine protocol for the application of DNA-SIP in the isolation of the active functional degraders from an environment.


2015 ◽  
Vol 81 (11) ◽  
pp. 3775-3781 ◽  
Author(s):  
Elyse A. Rodgers-Vieira ◽  
Zhenfa Zhang ◽  
Alden C. Adrion ◽  
Avram Gold ◽  
Michael D. Aitken

ABSTRACTQuinones and other oxygenated polycyclic aromatic hydrocarbons (oxy-PAHs) are toxic and/or genotoxic compounds observed to be cocontaminants at PAH-contaminated sites, but their formation and fate in contaminated environmental systems have not been well studied. Anthracene-9,10-dione (anthraquinone) has been found in most PAH-contaminated soils and sediments that have been analyzed for oxy-PAHs. However, little is known about the biodegradation of oxy-PAHs, and no bacterial isolates have been described that are capable of growing on or degrading anthraquinone. PAH-degradingMycobacteriumspp. are the only organisms that have been investigated to date for metabolism of a PAH quinone, 4,5-pyrenequinone. We utilized DNA-based stable-isotope probing (SIP) with [U-13C]anthraquinone to identify bacteria associated with anthraquinone degradation in PAH-contaminated soil from a former manufactured-gas plant site both before and after treatment in a laboratory-scale bioreactor. SIP with [U-13C]anthracene was also performed to assess whether bacteria capable of growing on anthracene are the same as those identified to grow on anthraquinone. Organisms closely related toSphingomonaswere the most predominant among the organisms associated with anthraquinone degradation in bioreactor-treated soil, while organisms in the genusPhenylobacteriumcomprised the majority of anthraquinone degraders in the untreated soil. Bacteria associated with anthracene degradation differed from those responsible for anthraquinone degradation. These results suggest thatSphingomonasandPhenylobacteriumspecies are associated with anthraquinone degradation and that anthracene-degrading organisms may not possess mechanisms to grow on anthraquinone.


2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Robert C. Kaplan ◽  
Zheng Wang ◽  
Mykhaylo Usyk ◽  
Daniela Sotres-Alvarez ◽  
Martha L. Daviglus ◽  
...  

Abstract Background Hispanics living in the USA may have unrecognized potential birthplace and lifestyle influences on the gut microbiome. We report a cross-sectional analysis of 1674 participants from four centers of the Hispanic Community Health Study/Study of Latinos (HCHS/SOL), aged 18 to 74 years old at recruitment. Results Amplicon sequencing of 16S rRNA gene V4 and fungal ITS1 fragments from self-collected stool samples indicate that the host microbiome is determined by sociodemographic and migration-related variables. Those who relocate from Latin America to the USA at an early age have reductions in Prevotella to Bacteroides ratios that persist across the life course. Shannon index of alpha diversity in fungi and bacteria is low in those who relocate to the USA in early life. In contrast, those who relocate to the USA during adulthood, over 45 years old, have high bacterial and fungal diversity and high Prevotella to Bacteroides ratios, compared to USA-born and childhood arrivals. Low bacterial diversity is associated in turn with obesity. Contrasting with prior studies, our study of the Latino population shows increasing Prevotella to Bacteroides ratio with greater obesity. Taxa within Acidaminococcus, Megasphaera, Ruminococcaceae, Coriobacteriaceae, Clostridiales, Christensenellaceae, YS2 (Cyanobacteria), and Victivallaceae are significantly associated with both obesity and earlier exposure to the USA, while Oscillospira and Anaerotruncus show paradoxical associations with both obesity and late-life introduction to the USA. Conclusions Our analysis of the gut microbiome of Latinos demonstrates unique features that might be responsible for health disparities affecting Hispanics living in the USA.


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