Somayeh Farahmand, Faezeh Fatemi, Reza Hajihosseini,
Volume 6, Issue 1 (5-2019)
Abstract
In Acidithiobacillus ferrooxidans, the proteins present in the electron transfer pathway cause ferrous iron oxidation which leads to uranium extraction. The relationship between gene sequence and uranium extraction has not been investigated yet. Based on the changes in uranium extraction, the changes of rus gene sequence can reveal the direct and accurate role of this protein. For this purpose, a random mutation was induced in native Acidithiobacillus sp. FJ2 by two doses of 0.8% and 1% of DES. Then, the bacteria was transferred into a medium which contained 50% uranium ore to carry out the bioleaching process. After measuring the amount of the extracted uranium, iron, Eh and pH, genomic DNA was extracted to investigate the rusticyanin gene (rus) sequence sent for sequencing after performing PCR. Then, the wild-type gene sequence was compared with the mutant by Bioedit v7.2.5 software. The results showed that uranium extraction increased by mutant bacteria with DES 1% between 7-11 days in comparison with wild bacteria. However, there has been no change in the functional areas of the rusticyanin gene. It seems that DES affected other effective genes in the electron transport chain or regulatory areas, which required further studies.
Mohsen Fatemi, Nasrin Mollania, Madjid Momeni-Moghaddam, Fatemeh Sadeghifar,
Volume 6, Issue 1 (5-2019)
Abstract
New properties of nano-materials have made nanotechnology the leading part of biology and medical sciences. Due to their various biomedical properties, iron-based magnetic nanoparticles (MNPs) have been highly considered by biological researchers. Nowadays, increasing resistance to antibiotics is a major problem in treating clinical infections. Finding new antibacterial agents is therefore essential for the treatment of resistant strains. In this study, the iron oxide MNPs were produced using culture-medium supernatant of a newly isolated bacterium to investigate the inhibitory effects of the NPs on strains with a major role in clinical infections. Biosynthesis of iron oxide MNPs were detected by UV-Vis spectroscopy and the average size of particles was estimated by dynamic light scattering technique. The anti-bacterial activity of these NPs against E. coli and S. aureus was investigated using methods for the calculation of bacterial sensitivity coefficient. In the presence of NPs, the highest sensitivity coefficient value was observed for E. coli in 1xMIC concentration. On the other hand, S. aureus showed the lowest value. The death rate of the two strains in contact with NPs followed the first order kinetic equation and the survival rate decreased with the increase of exposure time. The results of this study as well as the high functionality of iron oxide MNPs, make its application desirable in the prevention and treatment of clinical infections.
