The emergence and spread of antibiotics resistance in wastewater treatment systems have been pointed as a major environmental health problem. Nevertheless, research about adaptation and antibiotics ...resistance gain in wastewater treatment systems subjected to antibiotics has not been successfully developed considering bioreactor performance, microbial community dynamics and microbial activity dynamics at the same time. To observe this in autotrophic nitrogen removal systems, a partial-nitritation biofilter was subjected to a continuous loading of antibiotics mix of azithromycin, norfloxacin, trimethoprim, and sulfamethoxazole. The effect of the antibiotics mix over the performance, bacterial communities and bacterial activity in the system was evaluated. The addition of antibiotics caused a drop of ammonium oxidation efficiency (from 50 to 5%) and of biomass concentration in the bioreactor, which was coupled to the loss of ammonium oxidizing bacteria
in the bacterial community from 40 to 3%. Biomass in the partial nitritation biofilter experienced a sharp decrease of about 80% due to antibiotics loading, but the biomass adapted and experienced a growth by stabilization under antibiotics feeding. During the experiment several bacterial genera appeared, such as
, and
, clearly dominating the bacterial community with >20% relative abundance. The system reached around 30% ammonium oxidation efficiency after adaptation to antibiotics, but no effluent nitrite was found, suggesting that dominant antibiotics-resistant phylotypes could be involved in nitrification-denitrification metabolisms. The activity of ammonium oxidation measured as
and
gene expression dropped a 98.25% and 99.21%, respectively, comparing the system before and after the addition of antibiotics. On the other hand, denitrifying activity increased as observed by higher expression of
and
genes (83.14% and 252.54%, respectively). In addition, heterotrophic nitrification
was active only after the antibiotics addition. Resistance to the antibiotics was presumably given by
and
for azithromycin, mutations of the
and
for norfloxacin, and by
genes for sulfamethoxazole. Joined physicochemical and microbiological characterization of the system were used to investigate the effect of the antibiotics over the bioprocess. Despite the antibiotics resistance, activity of
decreased while the activity of
and
increased.
•A CANON bioreactor was subjected to a mix of antibiotics at high concentrations.•Nitrogen removal performance was irreversibly affected by the antibiotics.•Granular biomass changed its structure ...when exposed to antibiotics.•The fungus Scedosporium boydii proliferated under the antibiotics pressure.•The bacterial community structure shifted to antibiotics-resistant phylotypes.
An autotrophic nitrogen removal bioreactor with granular biomass was exposed to high antibiotics concentration in order to evaluate its impact over the performance and the biomass of this bioprocess. A mixture of azithromycin, norfloxacin, trimethoprim and sulfamethoxazole caused loss of autotrophic nitrogen removal performance, coupled to a deep change in the bacterial community diversity and structure of the granular biomass. Azithromycin, norfloxacin and trimethoprim were efficiently removed in the CANON bioreactor, reducing its concentration 77.9±11.2%, 51.7±10.7% and 57.8±8.1%, respectively. The granular biomass changed significantly with the addition of the antibiotics, decreasing in settling velocity but increasing in compactness, losing its inner porous structure but developing a protective outer layer build of cell material. Prolonged operation under the antibiotics loading promoted the adaptation of multi-drug resistant fungus Scedosporium boydii fungal species and of Acidovorax ebreus TPSY, Alcaligenes aquatilis, Paracoccus versutus or Ochrobactrum antropii, which have been identified as human, animal and/or plant pathogens.
Antibiotics, such as sulfonamides (SAs), have recently raised concern as wastewater treatment plants (WWTPs) partly remove them, and thus, SAs continuously enter the aquifers. In this context, the ...aims of this work are to (1) investigate the temporal evolution of SAs and metabolites in an urban aquifer recharged by a polluted river; (2) identify the potential geochemical processes that might affect SAs in the river-groundwater interface and (3) evaluate the ecological and human health risk assessment of SAs. To this end, 14 SAs and 4 metabolites were analyzed in river and urban groundwater from the metropolitan area of Barcelona (NE, Spain) in three different sampling campaigns. These substances had a distinct behavior when river water, which is the main recharge source, infiltrates the aquifer. Mixing of the river water recharge into the aquifer drives several redox reactions such as aerobic respiration and denitrification. This reducing character of the aquifer seemed to favor the natural attenuation of some SAs as sulfamethoxazole, sulfapyridine, and sulfamethizole. However, most of the SAs detected were not likely to undergo degradation and adsorption because their concentrations were constant along groundwater flow path. In fact, the intensity of SAs adsorption is low as the retardation factors are close to 1 at average groundwater pH of 7.2 for most SAs.
Finally, risk quotients (RQs) are used to evaluate the ecological and human health risks posed by single and mixture of SAs in river water and groundwater, respectively. Life-stage RQs of the SAs detected in groundwater for the 8 age intervals were low, indicating that SAs and their mixture do not pose any risk to human beings. Concerning the environmental risk assessment, SAs do not pose any risk for algae, fish and crustaceans as the RQs evaluated are further lower than 0.1.
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•14 sulfonamides (SAs) and 4 metabolites are analyzed in river and urban groundwater.•SAs present distinct behavior when river water infiltrates the aquifer.•Some SAs are naturally removed under the nitrate reducing groundwater conditions.•Other SAs are persistent as their concentrations remain constant along the flow path.•SAs pose no ecological and human health risks at detected concentrations.
Sulfonamide antibiotics and their metabolites do not pose any risk to human health in an urban aquifer that is a potential source of water supply.
Human malignant astrocytic tumors are the most common primary brain malignancies. Human gliomas are classified according to the extent of anaplasia or 'de-differentiation' appearance. Although this ...type of histological classification is widely accepted, the extensive heterogeneity of astrocytic tumors has made their pathological classification rather difficult. New genome-scale high throughput technologies for gene expression profiling, such as DNA microarrays, are emerging as new tools to allow a more accurate identification and characterization of different tumor degrees by discovering new specific markers and pathways of each stage. Present work reports interesting results that might be useful to differentiate between tumor grades. Data presented here provides new evidences about the molecular basis underlying different tumor stages. In this sense, we identified key metabolic pathways, crucial for tumor progression, as being differentially regulated in different tumor stages. On the other hand, remarkable findings regarding Notch pathway are reported, as some members of this receptor family were found to be differentially expressed depending on the malignancy degree. Our results clearly point out important molecular differences between different tumor stages and suggest that more studies are needed to understand specific molecular events characteristic of each stage. These types of studies represent a first step to deepen into the tumor physiology, which may potentially help for better and a more precise diagnosis of gliomas.
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