JOURNAL OF SCIENCE (KHARAZMI UNIVERSITY)
Year:2006 | Volume:6 | Issue:1-2|Papers Count:7

In this study the predicted epitopes of C2-V3-C3 domains of gp 120 of HIV-I, present in Iran, were compared to the epitopes of the homologous domains in subtypes A, B, C, D, E, F, G, H and I of this virus. Since epitopes are regions between the sequences with secondary structure which are hydrophilic and accessible, these parameters were used to predict the epitopes. The number of predicted helix (one) and sheet (five) regions in the Iranian isolate was equal to these numbers in subtypes A and F. Hubbard method recognized seven potential glycosylation sites on the Iranian isolate. In all other HIV-I viruses, the number of putative glycosylation sites was less. In all subtypes, including the Iranian one, an epitope in the same region was predicted. In all analyzed sequences (excluding the Iranian one and subtypes D and H) a single long epitope was predicted in another region. In subtype H no epitope was predicted in that region. Similar to subtype D in the Iranian subtype B, two short epitopes were predicted in the same part. The computational analysis predicted similarities and dissimilarities between the locations of epitopes of the Iranian and other HIV-I viruses. Although the primary structure of gpl20 of the Iranian HIV-I is highly related to subtype B, some differences were even predicted between the secondary and tertiary structure of the Iranian and consensus subtype B.

Cyanobacteria are a big groups of monera kingdom, that high potential for product some natural product, such as nutritional, pharmacologic material and etc. Oscillatoria is a kind of filamentous cyanobacteria. This microorganism observed in Tyab - bay in all of seasons. Seawater medium (SWM) is the best media for isolation of Oscillatoria from natural environment. Enriched SWM with B12 and semi-solid Z8 medium (0.7% agarose) is too suitable for purification of condense culture. Maximum coefficient (m) was in valance medium. Purification of Oscillatoria has down at during nine months.Oscillatoria was exposed to five treatments of light/ dark periods and six different temperatures. Results obtained revealed that among the employed 30oC treatment has had the best effect on increase maximum coefficient (m=0.602) and also another treatment among the employed 14.10 (light/ dark) hours (m=0.506). In this treatment temperature was 25 oC.

Ascochyta rabiei is one of the devastaining fungi pathogens of chick-pea (Cicer arietinum L.) crops. In the present investigation, forty-two Iranian isolates of Ascochyta rabiei fungi (including highly, weakly and moderate virulent isolates), whose pathogenisities were determined previously, were studied.Polygalacturonase is a main factor in the initiation of Ascochyta blight disease: Therefore fungi were cultured in Pectic Zymogram/ PZ (with pH 4.5) medium for six days. PG presence in culture media confirmed by test plate. Polygalactoronase/ PG activity assayed by Collmer methods. Clustring of isolates based on PG activity were performed by UPGMA (Unweighted pair grouped method by arithmatic average) method. Results indicated that PG activity differentiated RV from WV isolates from any province.Another study, DNA were extracted from mycelium by Dellaporta method, RAPD (Random Amplified Polymorphic DNA) reactions were performed by twelve arbitrary 9-10-mer primers. DNA polymorphism was studied in PCR products of the isolates using UPGMA method. Results showed that, the DNA amplification by RAPD (Ar171 and Ar082 primers) obtained high polymorphic pattern. On the other hand, genetic variability between isolates of A. rabiei was detectable but polymorphic pattern of these primers did not differentiate RV from WV isolates.

In a green house pot experiment, the effects of salinity and increasing levels of potassium supply on factors determining dry matter production of two barley cultivars(Reyhan and Aftal) were investigated, with regard to yield (Number of tillers and ears, dry weight of ears, straw, roots, thousand grain weight and leaf area). The plants were grown under four levels of potassium (K1=0, K2=0.25, K3=0.5 and K4=1 gr. K/Kg. soil) and 40mM NaCl in a randomized complete blocks design with four replication. The results indicated that by using of NaCl, the number of ears, dry weight of ears, thousand grain weight, biomass and leaf area increased, whereas dry weight of roots, the number of tillers per plant, duration of grain filling and maturity period in both cultivars decreased. Increasing of potassium supply significantly increased dry weight of shoots during vegetative growth, but during reproductive- and maturity growth had no marked influence on dry weight production. By increasing the levels of potassium accompanied with salinity no effects on above mentioned parameters were observed. This may be due to a high availability of potassium in the soil, which led to an increase in dry weight of the plant shoots.

A controversy in theories of loess formation is the origin of silt-size quartz grains which forms a large part of loess deposits. Glacial and eolian abrasion, physical and chemical weathering, vo1canismand alluvial processes all can produce a large quantity of silt-size quartz grain. Also many controversies still exit about the origin of loess sediments of the world. By investigation of quartz grains surface texture, the contribution of different environments in giving silt for these deposits can be evaluated which can help in finding the source of these sediments. Therefore, in this research, surface texture of quartz grains in 105-350 m and 75-105 m sizes of serve loess outcrops in Golestan Province were studied by binocular and Scanning Electron Microscope (SEM) and major and minor environments in producing silts were evaluated. Surface texture types on quartz grains are as follows: conchoidal, parallel, sub-parallel and stepwise fractures and sharp and angular relief. In the other hand, in some regions, surface textures are of irregular solution cavities and rounded grains are found. It is concluded that glacial processes are the main silt-producing mechanism for Golestan Loess Deposits and fluvial and chemical weathering are less important mechanisms.

One of the most important subjects of watershed basins is the protection of soil and water resources with regarding to control of erosion and sediment yield. The empirical methods for estimation of erosion rates and sediment yield measures such as PSIAC and EPM more emphasize environmental factors so mach so that the important lithological agents are not considered. Therefore, in this research attempts are made to propose a suitable and comprehensive method for inherent sensitivity of lithological units. To this end rock units are classified based on mineralogical composition and their textures in 10 orders of erodibility. The order of erodibility of each formation will be based on average of lithological components. This method is used for microcontinental plate of central Iran to evaluate the model. Based on outcomes of the mentioned classification, more than 83 percents of rock units are classified from moderate- weak to totally loose and sensitive order. In average, the basin is categorized as very sensitive to erosion. With regarding to obtained results in comparison to specific sediment yield rate that obtained from statistical analysis of observed measures, the accuracy and the ability of the method is confirmed.

Major cations, Fe, Mg and AI, in biotite are sensitive to magmatic processes and biotite chemistry could be used for petrogenetic investigation of granitioids. In this research composition of biotite from Boroujerd granitoids in Sanandaj-Sirjan Zone has been investigated in order to study its geochemical nature and petrogenesis. Separated biotites were analyzed by WDXRF and biotites in polished thin section were analyzed by EPMA. Samples were selected from Older granites (120 Ma) and Younger granites (60-70 Ma) after intensive petrographic examinations. Data from both techniques are in good agreement and discriminate two generation of granites clearly. Based on Mg, Mn, Fe3+, Fe2+, Ti and Al biotites in Younger granite incorporated more Mg than those in Older granites. The main differences between biotites in two generation of granites are amount of total Al and Fe/Fe+Mg ratio. Biotites in granodiorite and quartz diorite of Younger age are annite-phlogopite with 2.48-2.74 Al per formula unit, and Fe/Fe+Mg ratio of 0.375-0.600. Biotites from Older granites are annite-sidrophyllite with 2.76-3.69 and Fe/Fe+Mg ratio of 0.597-0.720. Composition of biotites indicates that two generation of granites formed under different oxygen fugacity and both are calcalkaline and shows I and S characteristics respectively.