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Showing 4 results for amoozegar
Comparison of Production of Carotenoid Pigments by ‎Prokaryotic Isolates of Iranian Saline Ecosystems and ‎Identification of Superior Isolate
A.a. Pourbabaee ‎, M.a. amoozegar ‎, S. Tavakoli , M. Rasooli ‎,
Volume 9, Issue 1 (Winter 2018)
Abstract
Aims: Carotenoids are a vast group of lipid-soluble pigments, which are produced by variety of microorganisms. The aim of this study was to compare the production of carotenoid pigments by prokaryotic isolates of Iranian saline ecosystems and identify superior isolate.
Materials & Methods: In this the experimental study, isolates were purified by culture-based methods and carotenoid extracts were analyzed by spectrophotometry in wavelength region of 400nm to 600nm. The total carotenoid content was estimated by spectrophotometry at λmax (490nm). Identity of bands was detremined by purification of bands by Thin Layer Chromatography (TLC) and analysis by High Pressure Liquid Chromatography (HPLC) and Fourier Transform Infrared Spectroscopy (FTIR).
Findings: Fourty-three isolates were obtained. Eight isolates were halotolerant bacteria, 8 isolates were moderately halophile, and 27 isolates were extremely halophile. All of the strains were capable of producing carotenoid compounds. Isolate M24 with 2054μg/g production was selected as superior isolate. Thin layer chromatography exhibited 6 colored bands in colored extract of this strain and the most concentrated band was purified. After purification by TLC and HPLC, spectrophotometry in UV range showed two pics at 530nm and 465nm as the highest absorbances, which were similar to UV absorbance of α-bacterioruberin. Phylogenetic analysis of 16S rRNA gene sequence of strain M24 showed that this strain had 98% similarity with Haloarcula amylolytica BD-3.
Conclusion: From Iranian Saline Ecosystems, 43 isolates are obtained. Eight isolates are halotolerant bacteria, 8 isolates are moderately halophile, and 27 isolates are extremely halophile. All of the isolates are capable of producing carotenoid compounds. Strain M24 is superior isolate, having 98% similarity with Haloarcula amylolytica BD-3.
Evaluation of Prokaryotic Diversity in Hypersaline Environment by Culture-independent Method
F. Jookar Kashi, P. Owlia, M.a. amoozegar,
Volume 9, Issue 1 (Winter 2018)
Abstract
Aims: Microorganisms are present not only in common environment, but also in extreme environments. Salt lakes with near or at saturating salinity are spread all over the world. Urmia Salt Lake is one of these hypersaline environments. The present study aimed at evaluating prokaryotic diversity in hypersaline environment by culture-independent method.
Materials and Methods: In this experimental study, different regions of Urmia Lake were sampled and the genomic material extracted from the water sample was used as a pattern for the amplification of 16S rDNA and a fragment of the bop gene via polymerase chain reaction. By cloning, each of the amplified fragments belonging to a single strain was amplified by T/A cloning vector. To further investigate the biodiversity of Haloarchaea, the biodiversity of bop gene was studied in addition to studying 16S rDNA.
Findings: By cloning and sequencing, 6 bacteria genera, including Acaryochloris, Adhaeribacter, Brachybacterium, Gloeocapsopsis, Cesiribacter, and Bacillus were identified. Archaeal library belonged to 5 genera, including Halonotius, Halolamina, Haloquadratum, Halomicroarcula, and Halorhabdus. The clone libraries of bacterial belonged to 4 phyla, including Bacteroidetes, Cyanobacteria, Actinobacteria, and Firmicutes. . The clone libraries of bop gene (as a molecular marker) belonged to genera, including Halorubrum, Natrialba, Haloquadratum, and Natrinema. The bop phylogeny was closely related to the 16S rDNA phylogeny.
Conclusion: By cloning and sequencing, 6 bacteria genera, including Acaryochloris, Adhaeribacter, Brachybacterium, Gloeocapsopsis, Cesiribacter, and Bacillus were identified. The bop phylogeny is closely related to the 16S rDNA phylogeny.

Synthesis of the MPA- Capped CdSe/ZnS Quantum Dots and Study the Quenching Effect of Azo Dyes on Them
F. Hajipour, S. Asad, M.a. amoozegar, Kh. Khajeh,
Volume 10, Issue 3 (Summer 2019)
Abstract
Quantum dots have received great attention for the past years as fluorescent markers for physical, chemical, and biological applications due to their unique size-dependent electrical and optical properties such as high extinction coefficient, broad absorption with narrow symmetric size-tunable fluorescent spectra, and strong resistance to photobleaching with significant luminescence quantum yield. In this study, at first the CdSe/ZnS quantum dots coated with oleylamine surface ligand were synthesized by high temperature injection method under vacuum conditions and stable nitrogen at 320°C. Then, in order to investigate the quenching effect of azo dyes, which is one of the most carcinogenic chemical colors used in various industries, on the emission of these nanoparticles, we used mercaptopropionic acid as a suitable hydrophilic ligand at the surface modification of quantum dots in the ligand exchange process as a proper aqueous phase transfer strategy. After confirming the proper synthesis of CdSe/ZnS nanoparticles by the transmission electron microscopy (TEM) test and the synthesized nanoparticle core and shell standard powder diffraction files (pdfs) in X-ray diffraction (XRD), the results of the studies showed that the methyl red due to its absorption spectrum overlapping with the emission spectrum of these quantum dots has a very powerful quenching effect on the emission of synthesized nanoparticles.

Application of calcium peroxide (CaO2) nanoparticles in naphthalene remediation from Groundwater: study the effect of temperature and pH on remediation efficiency
Fatemeh Gholami, Mahmoud Shavandi, Seyed Mohammad Mehdi Dastgheib, Mohammad Ali amoozegar,
Volume 11, Issue 4 (fall 2020)
Abstract
Application of oxygen releasing compounds (ORCs) is considered as a novel method in petroleum hydrocarbon remediation from groundwater. ORCs destroy chemically the contaminant by exposure to water which results in hydroxyl radical generation or biologically remove the pollution by biostimulation of the groundwater native microorganisms aerobically. In the present study, calcium peroxide (CaO2) nanoparticles were applied to supply the required oxygen for growth and activity of the native microorganisms to consume naphthalene (20 ppm) as a carbon source. Additionally, the effect of CaO2 content, temperature and pH on the performance of nanoparticles were investigated in the naphthalene removal. The results indicated that the microbial population was sharply increased in the presence of 400 mg/L of nanoparticles and at 30oC and the contaminant was completely removed after 20 days at neutral pH. Furthermore, naphthalene was 100% remediated from groundwater at pH 3, 7.4 and 12 after 2, 20 and 30 days, respectively. This proved the acceleration of chemical oxidation under the acidic condition. At 15 and 30 ± 0.5 oC the contaminant was removed from the media within 15 and 20 days respectively. Meanwhile, only 75% of contaminant was remediated from groundwater within 30 days at 4 ±0.5oC which was due to the reduction in the biological activity and the chemical reaction rate.
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