نشریه زیست فناوری دانشگاه تربیت مدرس
سال سوم شماره 1 (پیاپی 3، بهار و تابستان 1391)

Plants infected by arbuscular mycorrhizal fungi can tolerate and recover more rapidly from different biotic and abiotic stresses such as soil water deficits than uninfected plants. Thereby study of the dominant mycorrhiza species in the fields under drought stresses is very useful for increasing crop productivity in these conditions and promising for biological fertilizer production in the future. The objective of this research was to study the variations in morphological and molecular diversity of arbuscular mycorrhizal fungi (AMF) and identification of dominant AMF in wheat and barley fields of some arid and semi arid regions of Iran. For this purpose, about 66 samples containing root and rhizospher soils of wheat and barley plants were collected from some arid and semi arid regions of Iran (Isfahan, Tehran, Ghazvin, Arak, Tabriz). After trap culture of observed mycorrhiza in the samples, they were identified using morphological and molecular techniques. The ITS-rDNA of AMF in root DNA extracts of wheat and barley amplified with the primer pair LSU-Glom1/SSU-Glom1 as specific primer for AMF and ITS4/ITS5 as general primers in the first and second reactions of PCR (nested PCR), respectively. Aliquots of the positive second PCR products were cloned. Positive colonies were digested with Taq1. The restriction fragment length polymorphism (RFLP) patterns of digested samples were compared and 1-3 representatives of each pattern at each cloning reaction were sequenced. Morphological and molecular diversity of AMF showed that more than 90% AMF observed in the regions belong to genus Glomus which coordinates with morphological studies and followed by G. intraradices. Also these studies confirmed presence of following species in some regions: G. fasciculatum, G. geosporum, G. sinosum, G. constrictum, G. macrocarpum and Glomus sp. and Acaulospora (Acaulospora sp.). It is important to note that the species G. etunicatu and G. dimorphicum were not detected in the morphological studies and Glomus mosseae was the most dominant AMF species in the all studied regions.

Gold nanoparticles have received considerable attention in recent years because of their promising applications in diagnostic imaging, biosensors, biolabels, and drug and gene delivery systems. The chemical methods of nanoparticle synthesis are the most widely and traditionally used methods. Production of nanoparticles by chemical methods causes contamination from precursor chemicals due to the use of toxic solvents and generation of hazardous by-products. On the other hand, the physical methods have low yield and high cost. Hence, there is an increasing need to develop low cost, non-toxic, biocompatible and environmentally benign processes for synthesis of metallic nanoparticles where the biological approaches for synthesis of nanoparticles gain importance. In this study, we investigated the biosynthesis of gold nanoparticles using Streptomyces sp. ERI-3. Streptomycessp.ERI-3 was isolated from the soil of Ahar Copper Mine (Ahar, Iran) and its biomass was incubated at 28ºC on a rotary shaker (200 rpm) for 48 h. The nanoparticles were characterized by means of UV-vis spectroscopy, X-ray diffraction (XRD) and transmission electron microscopy (TEM).The nanoparticles exhibited maximum absorbance at 540 nm (special wavelength of gold nanoparticles) in UV-vis spectroscopy. The XRD spectrum of gold nanoparticles exhibited 2Ө values corresponding to the gold nanocrystals. The TEM micrographs revealed the extracellular and attached to cell surface formation of gold nanoparticles in the size range of 50-100 nm with spherical morphology.

Brain shrimp Artemia can tolerate different range of ecologic conditions. This animal is also known because of high nutrition value and special application in research. The species of Artemia franciscana found endemically on American continent, but recently it has been reported from Mahalru Lake, Iran. Due to differences between ecological conditions of Maharlu Lake with originally habitat of A. franciscana, Great Salt Lake, and taking to account the 10 years successful existence of this species in the lake, be believe that this species has adapted to new environment genetically. Given the fact that any kind of adaption can endanger endemic Maharlu parthenogenetic Artemia, in present study genetically differentiation between two populations of A. franciscana, before and after migration to new environment was studied. The study was conducted on structure of two important genes as COI and HSP26 using RCP-RFLP method. Successful digestion of the 700bp fragment of COI gene by two endonucleases enzymes, TaqI and EcoRI in addition to the digestion of 217bp fragment by Eco471 revealed genetic variation between two populations. The 7 generated specific haplotypes genetic distance of D=0.18 between the populations. According to the results and also successful residence of A. franciscana in Maharlu Lake, given the fact of high production performance of A. franciscana it is believed that the settler Artemia can be account as Iranian Artemia populations which will threaten existence of endemic parthenogenetic Artemia population in the lake.

Probiotics are live microbial feed supplements, which beneficially affect the host by improving its intestinal microbial balance[8].Recently, researches have shown that lactic Acid Bacteria(LAB), especially Bacillus (because of having endospore) remain stable at cooking temperature and retain their probiotic benefits in baked goods [3]. The purposeof this study,was using of Bacillus coagolans, as a resistant probiotic,for enrichment of bread. First, these probiotic bacteria were determined by the tests of salt tolerance, heat resistance, bile tolerance, tolerance of acid and pepcin, resistance of antibiotics, and preventing the growth of pathogenic starins[18].Then a certain number cells of BC were entered in bread dough,before& after baking the number of live bacteria were calculated by colony count in 1g of dough and bread. The number of BC decreased from 108 to 106 units per gram, after baking. Also,the amount of starch decreasd and changed into simple sugers. The pH was estimated about 4.5-5 and TTA (Total Titritable Acidity) was between 6-8. Finally, the enrichment of bread was evaluated by experts and its quality and taste were compared with a control sample. The Results showed this bacterium survives in baked bread and makes good chemical changes on it.

Lactic acid is the final product of anaerobic glycolysis, which is converted immediately into lactate. Most of the uptaken lactate is used as an aerobic substrate in skeletal muscle. Coenzyme Q10 is an essential electron carrier of the mitochondrial respiratory chain with antioxidant properties. It has been suggested that an intra-cellular shuttle is playing an important role in transferring lactate through mitochondrial membrane. Decreasing blood lactate concentration and its subsequent problems after a physical activity are of an important goals in physical performance. The Participants were 23 healthy young 20-30 years-old aerobic-trained women. They consumed 300mg/day of Coenzyme Q10 for 10 days. Blood lactate concentration and physical performance were measured at the beginning and at the end of the period using lactometer and Bruce test, respectively.At the beginning of the 10-day period blood, lactate concentration was 13.56±0.75 mmol/L, which was decreased to 11.12±0.67 mmol/L at the end of this period, significantly.Running time to exhaustion increased by 48.74±7.23 seconds significantly.Also VO2max increased by 3 Lit/min significantly. The results showed that the intake of 300 mg Coenzyme Q10 supplement in a 10-day period decreased blood lactate concentration and increased physical performance in the young trained women significantly.

The stability of recombinant proteins has become an increasingly important as more protein therapeutics are developed.In this study, the stability of recombinant human interferon gamma was investigated under storage condition for 0-9 months after production time at 4 and 25℃. The evaluation of biological activity, covalent dimerization, deamidation and oxidation of protein was done by cell culture, HPLC and SDS- PAGE. The results showed represents that antiviral activity was not decreased at 4℃ but decreased as temperature increased to 25℃. The inormation rate of deamidated and oxidized forms and covalent dimers at 25℃ was more rapid than 4℃. Therefore, rhIFN-γ has high stability at 4℃ comparing to 25℃.

Tyrosinase also known as polyphenol oxidase (PPO) is a copper-containing mono-oxygenase, which is responsible for melanization in animals and the enzymatic browning of fruits. It displays two distinct enzymatic activities: hydroxylation of monophenols to o-diphenols (monophenolase activity) and oxidation of the latter to o-quinones (diphenolase activity). The inhibition of tyrosinase is very important and encourages us to takes special attempts to search for new inhibitors. For the first time in the present study, the effects of 2-nitroaniline (a), 3-nitroaniline (b) and 4-nitroaniline (c) as well as their newly synthesized vanillin derivatives (2-nitrobenzenaminium 4-formil-2-metoxyphenolate (d), 3-nitrobenzenaminium 4-formil-2- metoxyphenolate (e) and 4-nitrobenzen aminium 4-formil-2-metoxyphenolate (f)) were studied on the oxidation of dopamine hydrochloride by mushroom tyrosinase. Among them, 4-nitroaniline (c) exhibited the strongest inhibitory effect, while acted as an activator. For these compounds, the IC50 follows the order of b> f= a> e> c. Compounds a, b and f were competitive while c and e were un-competitive inhibitors. The results indicated that the relative positioning of amino and nitro groups is important in the inhibition of the enzyme