Abstract: A growing number of initiatives on nanotechnology research, education and industry have been recently launched by several Arab countries to quickly build scientific capacity and track worldwide developments in nanotechnology. Some countries, namely the oil rich countries, have allocated large funds to support these initiatives which are intended to serve national interests in energy, water and food supply, medicine, and local industry. Other Arab countries are also pursuing nanotechnology, however with fewer funds but with more human resources.
This study assesses current status of nanotechnology in the Arab Republic of Egypt,
Hashemite Kingdom of Jordan, Kingdom of Morocco, Kingdom of Saudi Arabia, Republic of Tunisia, State of Kuwait, State of Qatar, Sultanate of Oman and United Arab Emirates. The study is aimed at having a top level overview of the status of existing, underdevelopment, and planed educational and research programs relevant to nanotechnology. The overview also includes nanotechnology research focus areas, challenges, and opportunities.
Abstract: The γ-irradiation effects on polyphenolic content and antioxidant capacity of parathion-pretreated leaves of Salvia officinalis plant were investigated. The analysis of phenolic extracts of sage without parathion showed that irradiation decreased polyphenolic content significantly (p < 0.05) by 30 and 45% at 2 and 4 kGy, respectively, compared to non-irradiated samples. The same trend was observed for the Trolox equivalent antioxidant capacity (TEAC), as assessed by the anionic DPPH and cationic ABTS radical-scavenging assays. The antioxidant potential decreased significantly (p < 0.01) at 2 and 4 kGy, by 11-20% and 40-44%, respectively. The results obtained with a pure chlorogenic acid solution confirmed the degradation of phenols; however, its TEAC was significantly (p < 0.01) increased following irradiation. Degradation products of parathion formed by irradiation seem to protect against a decline of antioxidant capacity and reduce polyphenolic loss. Ionising radiation was found to be useful in breaking down pesticide residues without inducing significant losses in polyphenols.
Abstract: There has been increased interest in the isolation of bacteria with a potential role in bioremediation from extreme environments such as phosphate mines containing various metals and radionuclides. This paper describes the isolation and characterization of a novel Micrococcus species from a phosphate mining region in the South of Tunisia, designated as strain BRM7. Colonies of bacterial strain BRM7 produced on Tryptone-Glucose-Yeast Extract (TGY) agar plates were yellow, smooth, circular and 0.5â1.5 mm in diameter. Cells of strain BRM7 were Gram-positive cocci, with a diameter of 0.7â1.0 μm. The most abundant cellular fatty acids of strain BRM7 were found to be anteiso-C15: 0 (49.42%) and iso-C15: 0 (32.63%). On the basis of its morphological attributes, biochemical characteristics, and partial sequencing of 16S rRNA gene (rDNA), the strain BRM7 belongs to the genus Micrococcus with 99% identity to Micrococcus luteus. Strain BRM7 grew well in tryptone, glucose and yeast extract (TGY) medium, and tolerated (1) high salt concentrations (up to 20%), (2) a wide range of pH (5.0â12.0), and (3) high temperatures (up to 45°C). The bacterial isolate Micrococus sp. BRM7 showed a high tolerance to strontium (Sr, D10 (dose for 90% reduction in Colony Forming Units (CFUs)) = 350 mM) with a similar tolerance curve to Cupriavidus metallidurans CH34, best known for its high tolerance to a wide range of heavy metals. Interestingly, Micrococus sp. BRM7 has an ionizing-radiation (IR) resistance D10 (ï¾800 Gy) four times higher than that of C. metallidurans. Immobilization into alginate beads indicated that Micrococus sp. BRM7 cells have the potential to adsorb 17 and 34% of Sr following an incubation time of 3 and 24 h, respectively. Overall, the results of this study suggest that BRM7 can be valorized to bioremediate Sr in radioactive residues like phosphogypsum (PG), an industrial concentrator of this toxic metal.
Abstract: The physiological and global transcriptomic response
of the metal-resistant bacterium Cupriavidus metallidurans
CH34 to stable non-radioactive strontium (Sr) was
investigated. C. metallidurans CH34 was able to survive
and proliferate in the presence of relatively high concentrations
of SrCl2 (concentration of Sr needed to inactivate 90 %
of the cells070 mM; minimum inhibitory concentration 0
120 mM). Gene expression in cells was analyzed after shortterm
(30 min) exposure to low (5 mM) and high (60 mM)
concentrations of SrCl2. The transcription of the gene clusters
annotated as hmyFCBA and czcCBADRS, coding for ion
efflux pumps, was significantly induced following exposure
to Sr relative to that in non-stressed CH34 cells. Sr precipitation
was observed during aerobic growth of CH34 in the presence of
60 mM SrCl2. Transmission electron microscopy images of
cells grown with Sr also showed very small solid-phase precipitates
located in the vicinity of cells, but mainly extracellular.
Environmental scanning electron microscopy with energydispersive
X-ray spectrometry indicated that the sequestered
extracellular solid-phase Sr was present in the form of strontium
carbonate.
