58 research outputs found
Use of microbial fuel cells for soil remediation. A preliminary study on DDE
DDE (2,2-bis (p-chlorophenyl)-1,1-dichloroetylene) is a very persistent and bioaccumulative pesticide and its residues are continuously found in the environment. Among the green remediation strategies for soil recovery, terrestrial Microbial Fuel Cells (MFC) are arousing great interest in scientific community. MFCs transform energy stored in the chemical bonds of organic compounds into electrical energy thanks to exo-electrogen microorganisms naturally occurring in soil, which catalyse oxidation and reduction reactions in the area between two graphite electrodes. This work reports preliminary data on the use of MFCs for promoting soil decontamination from DDE. Several experimental conditions (e.g. addition of compost and open/closed circuit) were applied for assessing how to improve MFC performance in favouring DDE removal. MFCs promoted a significant DDE removal (39%) after 2 months, while at the same time any pesticide decrease was observed in the batch condition. Compost addition stimulated microbial activity and improved MFC performance for a longer time
A new fluorescent oligonucleotide probe for in-situ identification of Microcystis aeruginosa in freshwater.
contaminated water bodies (freshwater, brackish and marine areas). Among 150 known cyanobacteria genera,>40
species are able to produce toxins, which are natural compounds that differ from both a chemical and toxicological
point of view and are responsible for acute and chronic poisoning in animals and humans. Among the main classes of cyanotoxins, microcystins are frequently found in the environment. Fast and accurate methods for unequivocally identifying microcystin-producing cyanobacteria, such as Microcystis aeruginosa in water bodies, are necessary to distinguish them from other non-toxic cyanobacteria and to manage and monitor algal blooms. For this purpose, we designed, developed and validated an oligonucleotide probe for FISH (Fluorescence In Situ Hybridization) analysis to detect Microcystis aeruginosa at the species level even at relatively low concentrations in freshwater. The FISH probe, MicAerD03, was designed using the ARB software with the Silva database within the framework of the MicroCoKit project, also with the intention of adding it to the microarray from the EU project, μAQUA, for freshwater pathogens, which had only genus level probes for Microcystis. We tested various fixative methods to minimize the natural autofluorescence from chlorophyll-a and certain
accessory pigments (viz., phycobilins and carotenoids). The FISH probe was tested on pure cultures of Microcystis
aeruginosa, and then successfully applied to water samples collected from different sampling points of the Tiber
River (Italy), using a laser confocal microscope. Subsequently, the probe was also conjugated at the 5′ end with horse-radish peroxidase (HRP-MicAerD03) to apply the CAtalysed Reported Deposition-FISH (CARD-FISH) for
increasing the fluorescence signal of the mono-fluorescently labelled probe and make it possible to detect M. aeruginosa using an epifluorescence microscope. Samples taken within the EU MicroCokit project indicated thatmicroarray signals for Microcystis were coming from single cells and not colonial cells. We confirmed this with
the CARD-FISH protocol used here to validate the microarray signals for Microcystis detected at the genus level in
MicroCokit. This paper provides a new early warning tool for investigating M. aeruginosa at the species level even at low cell concentrations in surface water, which can be added to the μAqua microarray for all freshwater pathogens to complete the probe hierarchy for Microcystis aeruginosa
Degradation of the antiviral drug oseltamivir (Tamiflu) in surface water samples
Numerous studies have documented that a wide number of pharmaceuticals used in human and
veterinary medicine have the potential to enter the aquatic ecosystem. The antiviral prodrug
oseltamivir phosphate has received recent attention with regard to its possible use against the
highly pathogenic H5N1 virus. This preliminary laboratory study investigated the persistence of
the active antiviral drug, oseltamivir carboxylate (OSC), in water samples taken from an
irrigation canal. After an initial rapid decrease, OSC concentrations slowly decreased during
the remaining incubation period. Approximately 65% of the initial OSC amount remained in
water at the end of the 36-day incubation period. A small amount of OSC was lost both from
sterilized water and from sterilized water/sediment samples, suggesting a significant role for
microbial degradation. Stimulating microbial processes by the addition of sediments resulted
in reduced OSC persistence. Presence of OSC (1.5 mgmL1) did not significantly affect the
metabolic potential of the water microbial population, estimated by glyphosate and
metolachlor mineralization. In contrast, OSC caused an initial transient decrease in the size
of the indigenous microbial population of water samples
- …