Impact of liquid hog manure applications on antibiotic resistance genes concentration in soil and drainage water in field crops
CANADIAN JOURNAL OF MICROBIOLOGY
Authors: Larouche, Elodie; Genereux, Mylene; Tremblay, Marie-Eve; Rhouma, Mohamed; Gasser, Marc-Olivier; Quessy, Sylvain; Cote, Caroline
Agricultural practices such as manure applications could contribute to the spread of antibiotic resistance genes (ARGs) within the environment. Our objective was to assess the impact of certain fertilization methods (mineral or manure) and tillage practices (reduced or conventional) on the presence of ARGs and bacteria in soil and drainage water under wheat and grain corn crops. Targeted ARGs tet(T), sul1, and bla(CTX-M-1) in liquid hog manure, soil, and water samples were quantified by qPCR. Conventional PCR was used to detect mcr-1 and mcr-2. ARGs in control plots were detected despite the absence of manure, representing an environmental reservoir of resistant microorganisms. The manure application rate higher than 39 m(3)/ha increased tet(T) and sul1 gene concentrations in soil for more than 180 days. Tillage practices had no impact on ARG concentrations in soil and water samples. The bla(CTX-M-1) gene was only detected in seven water samples in 2016, but no link was established with the treatments. The mcr-1 and mcr-2 genes were not detected in all tested samples. This study demonstrated that tet(T) and sul1 gene concentrations increased in soil after liquid hog manure application as well as in drainage water in the next weeks.
Biodegradation of Novacron Turqueiose (Reactive Blue 21) by Pseudomonas aeruginosa
JOURNAL OF THE CHEMICAL SOCIETY OF PAKISTAN
Authors: Ikram, Muhammad; Zahoor, Muhammad; Khan, Ezzat; Khayam, Sahibzada Muhammad Umar
In the present study four bacterial strains Escherichia Coli, Salmonella typhi, Shiegella and Pseudomonas aeruginosa were used to evaluate their dye decolorization/degradation ability. Out of these bacterial strains Pseudomonas aeruginosa exhibited high potential for selected dye decolorization and hence it was used in subsequent experiments. The effect of dye concentration, pH, temperature, time, glucose and sodium chloride concentrations on decolorization were also studied to determine the optimal conditions required for maximum decolorization/degradation of selected dye by Pseudomonas aeruginosa. Maximum decolorization was observed at: 0.01 mg/L dye concentration, pH 10, temperature 45 degrees C, 0.1 mg/L glucose concentration, 0.1 mg/L sodium chloride concentration and 3 days incubation period at 37 degrees C. The metabolites formed after degradation by selected bacteria at optimum conditions were isolated and characterized by FTIR and mass spectrometry. In the mass spectra molecular ion peak was not observed and it was difficult to draw a conclusion from it. However, FTIR spectra provided some valuable information. The peaks at 1301.8 cm(-1) for C-N and 1231.5 cm(-1) for O-H stretch observed for original dye were completely absent in the decolorized products. The disappearance of C-N (part of the porphyrin ring system) peak in FTIR spectra shows that the porphyrin ring has been destroyed by bacteria. The extensive fragmentations in the mass spectra also confirm the degradation of the dye parental structure.