Rapid Impact of Phenanthrene and Arsenic on Bacterial Community Structure and Activities in Sand Batches

Abstract

The impact of both organic and inorganic pollution on the structure of soil microbial communities is poorly documented. A short-time batch experiment (6 days) was conducted to study the impact of both types of pollutants on the taxonomic, metabolic and functional diversity of soil bacteria. For this purpose sand spiked with phenanthrene (500 mg kg(-1) sand) or arsenic (arsenite 0.66 mM and arsenate 12.5 mM) was supplemented with artificial root exudates and was inoculated with bacteria originated from an aged PAH and heavy-metal-polluted soil. The bacterial community was characterised using bacterial strain isolation, TTGE fingerprinting and proteomics. Without pollutant, or with phenanthrene or arsenic, there were no significant differences in the abundance of bacteria and the communities were dominated by Pseudomonas and Paenibacillus genera. However, at the concentrations used, both phenanthrene or arsenic were toxic as shown by the decrease in mineralisation activities. Using community-level physiological profiles (Biolog Ecoplates™) or differential proteomics, we observed that the pollutants had an impact on the community physiology, in particular phenanthrene induced a general cellular stress response with changes in the central metabolism and membrane protein synthesis. Real-time PCR quantification of functional genes and transcripts revealed that arsenic induced the transcription of functional arsenic resistance and speciation genes (arsB, ACR3 and aioA), while no transcription of PAH-degradation genes (PAH-dioxygenase and catechol-dioxygenase) was detected with phenanthrene. Altogether, in our tested conditions, pollutants do not have a major effect on community abundance or taxonomic composition but rather have an impact on metabolic and functional bacterial properties.

Continous application of bioorganic fertilizer induced resilient culturable bacteria community associated with banana Fusarium wilt suppression

“…The substrates in Biolog Ecoplates can be assigned to guilds of carbohydrates, amino acids, carboxylic acids, amines, phenolic acids and polymers according to their chemical nature28 (Supplementary Table S2). The time course changes of the six types carbon substrates AWCD data was successfully fitted a modified form of the logistic equation (χ 2  ≤ 0.013 and R 2  ≥ 0.97, data not shown) and the parameters were calculated (Table 1).…”

Response of rhizosphere microbial community structure and diversity to heavy metal co-pollution in arable soil

“…In tested conditions, pollutants (phenanthrene and arsenic) did not have a major effect on community abundance or taxonomic composition but rather had an impact on metabolic and functional bacterial properties (Cebron et al 2014). Liu et al (2012) revealed a consistent change in soil microbial community under heavy metal pollution of rice paddy across South China.…”

Proteomic tools to decipher microbial community structure and functioning

“…This approach limits inter-gel variation of migration and is therefore more robust than Coomassie-stained 2D-GE. Such an approach was recently applied to community proteomics to analyze proteins specifically expressed in the presence of phenanthrene (Cébron et al 2014 ).…”

“…The identification of signature peptides in orthologs has enabled the use of some proteins involved in conserved biological processes as taxonomic signatures. Such an approach was used to describe the active community at the genus level in the Carnoulès AMD (Bruneel et al 2011 ), in a mildly arsenic contaminated creek (Halter et al 2011 ) or in microcosms obtained from a community of phenanthrene-contaminated soil (Cébron et al 2014 ).…”

“…In those communities, proteins were identified belonging to an uncultured organism of the Rhodocyclus lineage known to accumulate polyphosphates (Wilmes and Bond 2004 ), but also originating from human or marine bacteria (Kuhn et al 2011 ). Metaproteomics was recently applied to batch cultures in order to analyze an anaerobic microbial community degrading toluene or to study the effect of arsenic and phenanthrene on a bacterial community originating from an aged PAH and heavy-metal-contaminated soil (Jehmlich et al 2010 ; Cébron et al 2014 ). Similarly, the effects of temperature and exposure to trichloroethylene (TCE) on proteins expressed by the community in laboratory-scale anaerobic conditions were analyzed (Siggins et al 2012a ).…”