Exploring the glyphosate-degrading characteristics of a newly isolated, highly adapted indigenous bacterial strain, Providencia rettgeri GDB 1.

This study explored the characteristics of a newly isolated glyphosate (GLYP)-degrading bacterium Providencia rettgeri GDB 1, for GLYP bioremediation. Due to the serial selection pressure of high GLYP concentrations for enriched isolation, this highly tolerant GLYP biodegrader shows very promising capabilities for GLYP removal (approximately 71.4% degradation efficiency) compared to previously reported strains. High performance liquid chromatography analyses showed aminomethylphosphonic acid (AMPA) rather than sarcosine (SAR) to be the sole intermediate of GLYP decomposition via the AMPA formation pathway. Moreover, GLYP biodegradation was biochemically favorable in aerobic cultures due to its strong growth-associated characteristics. To the best of our knowledge, this is the first report to indicate that bacterial strains in the Providencia genus could demonstrate highly promising GLYP-degrading characteristics in environments with high GLYP contents.

Deciphering synergistic characteristics of redox mediators-stimulated echinenone production of Gordonia terrae TWIH01.

This first-attempt study tended to decipher synergistic interactions of model redox mediators (RMs) to echinenone production for electrochemically-steered fermentation (ESF). The findings indicated that supplement of RMs could significantly stimulate the production performance of fermentation (e.g., 36% for 4-aminophenol) which was parallel with stimulation of bioelectricity generation in microbial fuel cells (MFCs) as prior studies mentioned. Although redox mediators could usually enhance electron transport extracellular compartment, the mechanisms of bioelectricity generation in MFCs and echinenone production in ESF were very likely functioned in the extracellular and the intracellular compartment, respectively. In MFCs, electron transfer towards biofilm anode for bioelectricity generation must be taken place. However, for ESF echinenone accumulation was very likely occurred in the intracellular compartment, thus electron transfer was predominantly implemented in the intracellular, not the extracellular compartment.

Fluorescence resonance energy transfer-based ratiometric fluorescent probe for detection of Zn(2+) using a dual-emission silica-coated quantum dots mixture.

In this work, we report the design and application of a new ratiometric fluorescent probe, which contains different-colored quantum dots (QDs) as dual fluorophores, ultrathin silica shell as spacer, and meso-tetra(4-sulfonatophenyl)porphine dihydrochloride (TSPP) as receptor, for Zn(2+) detection in aqueous solution and living cells. In the architecture of our designed probe, the silica shell plays the key roles in controlling the locations of QDs, TSPP, and Zn(2+), preventing the direct contact between QDs and Zn(2+) but affording fluorescence resonance energy transfer (FRET) from dual-color QDs to TSPP. In the presence of Zn(2+), the analyte-receptor reaction changes the absorption in the range of the Q-band of TSPP and accordingly the efficiencies of two independent FRET processes from the dual-colored QDs to the acceptor, respectively, leading to fluorescence enhancement of green-emission QDs whereas fluorescence quenching of yellow-emission QDs. Benefiting from the well-resolved dual emissions from different-colored QDs and the large range of emission ratios, the probe solution displays continuous color changes from yellow to green, which can be clearly observed by the naked eye. Under physiological conditions, the probe exhibits a stable response for Zn(2+) from 0.3 to 6 µM, with a detection limit of 60 nM in aqueous solutions. With respect to single-emission probes, this ratiometric probe has demonstrated to feature excellent selectivity for Zn(2+) over other physiologically important cations such as Fe(3+) and Cu(2+). It has been preliminarily used for ratiometric imaging of Zn(2+) in living cells with satisfying resolution.