University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
12
4
2001
12
01
A COMPARATIVE STUDY BETWEEN EXPRESSION OF A SYNTHETIC GENE OF HUMAN BASIC FIBROBLAST GROWTH FACTOR (hbFGF) AND ITS RELATED cDNA IN ESCHERICHIA COLI
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31779
EN
Journal Article
1970
01
01
The gene encoding the human basic fibroblast growth factor (hbFGF) has been already chemically-synthesized and cloned in pET-3a expression vector (Pasteur Institute of Iran). In the present study, we compared the level of expression of this synthetic hbFGF and its related cDNA in Escherichia coli. The pBR322-cDNA of hbFGF supplied by Dr. Seno (from Molecular Biology Dept, Okaido prefectural university, Japan), was utilized to introduce two restriction sites (BglII and NdeI) in either ends of the gene by PCR. This PCR product was inserted into SmaI site of pUC18 plasmid (pUC-1003). This construct was inserted into BamHI site of pET-3a expression vector (pET-1004). A final construct for expression of the gene was also made (pET-1005). The level of expression of the synthesized gene was compared to that of the cDNA using SDS-PAGE, western-blotting or ELISA. The results showed that expression of the hbFGF cDNA was much higher than that of the related synthetic gene, (16 mg/l and 0.025 mg/l respectively). Although in designing the synthetic gene the “codon usage” of E. coli was considered, it seems that “codon usage” did not improve the level of expression of the gene as was expected.
https://jsciences.ut.ac.ir/article_31779_6b4285c38d642013c7ea1539056ffc47.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
12
4
2001
12
01
MOLECULAR CLONING AND EVALUATION OF WILD PROMOTER IN EXPRESSION OF BACILLUS SPHAERICUS PHENYLALANINE DEHYDROGENASE GENE IN BACILLUS SUBTILIS CELLS
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31780
EN
Journal Article
1970
01
01
To evaluate the role of wild promoter of L-phenylalanine dehydrogenase (PheDH) gene, referred to as pdh, from Bacillus sphaericus in expression, cloning of pdh gene in Bacillus subtilis was performed. The whole pdh gene was cloned in pHY300PLK shuttle vector and amplified, construct (pHYDH) then transformed in B. subtilis ISW1214 and E. coli JM109. The pdh endogenous promoter presented no effect on transcription of the target gene in E. coli JM 109. But B. subtilis ISW1214/pHYDH produced PheDH enzyme (4700 U/L). The level of PheDH protein expression with native promoter was about 12%. It was purified to near homogeneity as judged by SDS-polyacrylamide gel electrophoresis (Mr
41 kDa) and the result was 18 fold with a yield of about 31%. The Mr of PheDH was estimated to be approximately 340 kDa (octamer) by a gel filtration on a G-200 sephadex column. Apparent Km values for L-phenylalanine, L-tyrosine and NAD+ were 0.24 mM, 0.48 mM and 0.19 mM respectively. The optimum pH of the recombinant enzyme was 11 for the oxidative deamination, 10.2 for the reductive amination. The features of recombinant PheDH enzyme were compatible with the wild type PheDH protein.
https://jsciences.ut.ac.ir/article_31780_69af5e2ce3effce6d2ef0ee9688ae231.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
12
4
2001
12
01
EPIDEMIOLOGICAL SURVEY OF DIFFERENT RABIES VIRUS STRAINS IN IRAN
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31781
EN
Journal Article
1970
01
01
Rabies is widespread in all provinces of Iran. This study presents an investigation by a Polymerase Chain Reaction (PCR) technique for the purpose of rabies diagnosis and also Restriction Fragment Length Polymorphism (RFLP) for determination of the type of the rabies virus. In addition, PCR proves to be a powerful tool for molecular epidemiology studies allowing analysis of the infecting strains without prior cell culture adaptation. In this study, the type of rabies viruses isolated from 50 brain samples of various hosts from different provinces of the country was determined by restriction analysis (RFLP) on pseudogene ? fragment as the most divergent genomic area. The results indicate that the viral strains belong to serotype/genotype 1.
https://jsciences.ut.ac.ir/article_31781_61a4dcd12041e2244c18eead5ef50f6f.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
12
4
2001
12
01
EVALUATION OF THE USE OF ANIONIC/ NONIONIC MIXED MICELLES IN REVERSED PHASE LIQUID CHROMATOGRAPHY
OF CHLOROPHENOLS
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31782
EN
Journal Article
1970
01
01
The use of aqueous mixed micellar system consisting of sodium dodecyl sulfate (SDS) and polyoxyethylene (23) dodecanol (Brij-35) as the mobile phase in reversed-phase liquid chromatography was studied. A group of chlorophenols was used as the test mixture. Adding organic modifier to the system showed that the use of low concentrations of organic additives improves efficiency in SDS/Brij-35 mixed micellar mobile phase. The effects of propanol concentration, total surfactant concentration and pH upon retention and selectivity were also assessed. It was shown that a linear correlation exists between LnK? and volume fraction of propanol over a range of 0-10%. Also, a regular decrease in solutes retention was observed as a function of surfactant concentration. The results showed that the elution strength increases as the mobile phase pH decreases. It was also revealed that the chromatographic selectivity changes with an increase in elution strength.
https://jsciences.ut.ac.ir/article_31782_6c67147c4aae30c0666084dc081bf5ea.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
12
4
2001
12
01
SURFACE MODIFICATION OF ANALCIME FOR REMOVAL OF NITRITE AND NITRATE FROM AQUEOUS SOLUTIONS
-
31783
EN
Journal Article
1970
01
01
The capacity of natural zeolites to absorb anionic pollutants from water is limited. This limitation can be overcome by modifying the surface of the minerals with organic cations. In this research, natural zeolite, Analcime was used for removing the nitrate and nitrite impurities from aqueous solutions. The surface of the zeolite was modified by tetramethylammonium and tetraethylammonium ions to increase the capacity of the samples to absorb the anions. The modified zeolite showed higher affinity for NO2– and NO3– compared to the natural sample.
https://jsciences.ut.ac.ir/article_31783_422f088120e78375a9ce22560e37c444.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
12
4
2001
12
01
KINETICS AND MECHANISM OF GRAFT POLYMERIZATION OF ACRYLONITRILE ONTO STARCH INITIATED WITH POTASSIUM PERSULFATE
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31784
EN
Journal Article
1970
01
01
A new potassium persulfate redox system has been investigated for the graft polymerization of vinyl monomers. In this study potassium persulfate system was used for initiation the polymerization. Graft polymerization of acrylonitrile (AN) onto starch (Sta) was carried out in aqueous solution using potassium persulfate (I) redox system. It was found that the percentage of grafting and rate of grafting were all dependent to some extent, on the concentration of the I, AN, Sta and Sta/ water as well as reaction time and temperature. The kinetics of the graft polymerization of AN onto Sta in aqueous solution was studied by Kjeldahl method (quantity and qualitative determination nitrogen content), and the kinetics of AN homopolymerization in the same system was studied by bromometry titration (residue monomer determination). The following rate expression (rate of graft polymerization and rate of homopolymerization) Rg=k?[AN]1.185?[I]0.499?[Sta]0.497 and Rh=k?[AN]1.359?[I]0.436 were obtained and a suitable mechanism was suggested. The graft copolymer was investigated with an infrared spectroscope. The overall activation energy was found to be 56.95 kJ/mol within the temperature range of 40-65°C.
https://jsciences.ut.ac.ir/article_31784_1dfc7ed41064f8c4f2b5a8f4c70224bf.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
12
4
2001
12
01
SLOPE PROFILE MORPHOMETRY AS AN INDICATOR FOR SLOPE MOVEMENT
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31785
EN
Journal Article
1970
01
01
Two dimensional slope profile morphometric investigation in a part of the land failure prone Garhwal region of the Lesser Himalaya, Tehri district, U. P., India, indicates that the landslip morphology is closely related to the dominant movement processes active in this terrain. Technique developed for the morphometric analysis of landslips involves the use of five morphometric indices. Each index has been formulated to give an indication of the processes responsible for producing variation on landslip form. The measurements indicated the degree of dilation, flowage, displacement and tenuity. The depth/length ratio is used as a numerical parameter to classify landslips into process groups. Multivariate discriminant function criteria have been worked out to differentiate between various slope movement processes. The result indicated that among all two dimensional slope profile morphometric indices, Classification, Dilation and Tenuity indices contribute significantly in discriminating various slope movement processes. Based on these indices, bivariate and univariate plots have been prepared as discriminant tools to predict various types of slope movements.
https://jsciences.ut.ac.ir/article_31785_c39ed1415f9ae4166cb31339d5057005.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
12
4
2001
12
01
STRESS INTENSITY FACTORS FOR AN INTERIOR GRIFFITH CRACK OPENED BY HEATED WEDGE IN A STRIP WHOSE EDGES ARE NORMAL TO CRACK AXIS
-
31786
EN
Journal Article
1970
01
01
After second world war, we have seen a very rapid development of Thermoelasticity stimulated by various engineering sciences. As we know, structures behave in different fashion under climate variation and the most responsible factor for these variations is heat which falls through and causes deformation of the body. A considerable progress in the field of aircraft and machine structures, mainly with gas and steam turbine and the emergence of new topics in chemical and nuclear engineering, have given rise to numerous problems in which thermal stresses play an important and frequently even a primary role. The concern of the present paper is the problem of an interior Griffith crack opened by heated wedge in a strip whose edges are normal to crack axis and the medium is assumed to be homogenous and isotropic. Under plane strain condition the closed form expressions for the stress intensity factors and the crack shape are obtained by use of Fourier transform technique. Two special cases of heat distributions are discussed in the end when wedge geometry is prescribed.
https://jsciences.ut.ac.ir/article_31786_a85945550bd2a6f22f16d949517850f2.pdf
University of Tehran
Journal of Sciences, Islamic Republic of Iran
1016-1104
12
4
2001
12
01
DIFFUSE REFLECTANCE MEASUREMENTS FROM DIFFERENT SURFACES
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31787
EN
Journal Article
1970
01
01
Relative diffuse reflection measurements from the original and ground surfaces using a He-Ne laser are reported. The intensity measurements for the metallic, transparent dielectric, matte plastic surfaces and colored papers are presented. Our results indicate that among metallic surfaces tested, aluminum has the highest diffuse reflectance; while the original stainless steel surface shows the lowest. The primary result is that for the ground metallic surfaces, there seems to be an optimum condition and roughness that result in the maximum diffuse reflection. For the color matte plastics, the yellow color has the highest diffuse reflectance and the black one shows the lowest. For the colored papers the yellow paint shows a maximum diffuse reflectance; whereas the gray one has the lowest diffuse reflectance. Our results agree with the theoretical predictions and also with the other experimental results.
https://jsciences.ut.ac.ir/article_31787_b71151669918539952971d00dbc3ef50.pdf