Journal of Sciences, Islamic Republic of Iran
Year:2009 | Volume:20 | Issue:4|Papers Count:8

Chaperones are produced by prokaryotic, yeast and higher eukaryotic cells for various purposes. Over-expression of each chaperone or sets of them affect the production level of a recombinant protein in the cell. On the basis of this hypothesis, five different plasmids with 5 different combinations of 6 chaperones molecule, transformed into Escherichia coli along with human basic Fibroblast Growth Factor expression plasmid. Each transformant that contain both plasmids for expression of hbFGF and chaperone combinations was induced with proper concentration of related inducers. Subsequently, total amount of produced hbFGF was analyzed based on SDS-PAGE and ELISA. Our results indicated that “TF” and “DnaK/DnaJ/GrpE” destabilized hbFGF, while “DnaK/DnaJ/GrpE/GroEL/GroES” and “GroEL/GroES” combinations were able to stabilize it. It has also revealed that “GroEL/GroES/TF” combination negatively affected the hbFGF production.

Phenylalanine dehydrogenase (PheDH; EC 1.4.1.20) is an important enzyme of amino acid dehydrogenases family that increasingly used as a valuable biocatalyst in neonatal screening kits and synthesis of L-phenylalanine. The goal of this literature was to find a suitable purification method for recombinant Bacillus badius PheDH by practical comparison between chromatographic and polyvinyl pyrrolidone (PVP)/Na2SO4 aqueous two-phase systems (ATPS) techniques. The partitioning behavior of target enzyme in PVP/Na2SO4 ATPS was examined and compared with the obtained results from a chromatographic protocol. Direct comparison of chromatography and ATPS procedures clearly revealed that the ATPS consisting of 8.0% (w/w) PVP, 17.0% (w/w) Na2SO4 with pH of 8.0, VR=0.25 and temperature of 25oC was the most desirable process for PheDH purification. A specific activity of 1231.42 U/mg, a purification factor of 36.61, a ield of 95.5% and a recovery of 138.9% were achieved. Altogether, we presented a two-phase methodology as a scalable and economically alternative for the production of PheDH enzyme.

In the present study a new economic and rapid bacterial micro-assay for simultaneous detection and quantitative measurement of serum galactose was developed. Analysis of the standard curve showed a linearity range for galactose from 2 mg/dL to 180 mg/dL with a regression equation of Y=0.013X - 0.083; R²=0.962. The advantage of the method is its ability to measure serum galactose quantitatively. The cost per sample is about 20-50 cents, which is much less than HPLC and enzymatic commercial kits. The method can be automated, which is suitable for galactosemia neonatal and mass screening especially in developing countries in which funding is a limiting factor.

Cancer is not just one disease, but a large group of almost one hundred diseases. Its two main characteristics are uncontrolled growth of the cells in the human body and the ability of these cells to migrate from the original site and spread to distant sites. If the spread is not controlled, cancer can result in death.There has been continuous progress in the development of therapy for cancer. The successful treatment of cancer still remains a challenge. A new series of pyrido[2,3-c]pyridazine derivatives (8-14) were synthesized and screened for their anticancer activity. Amongst them few of the compounds have exhibited promising cytotoxicity along with good safety index. These compounds could be of use in designing new anti-cancer agents.

Pleistocene basaltic lava flows, consisting of trachybasalt and basaltic trachyandesite, cover an area north-northwest of Shahre-Babak in southeastern Iran. The whole rock chemistry indicates that the lavas are dominantly alkaline and mildly calc-alkaline. Variation diagrams of SiO2 with major and trace elements are consistent with fractional crystallization processes involving olivine, pyroxene, plagioclase, ± hornblende and Fe-Ti oxides. In both rock types trace element variations show similar high LILE/HFSE ratios, which along with their similar fractionation trend, implying a common magma source but different degrees of evolution. Their MORB normalized incompatible trace element concentrations show enrichment in LILE (e.g., Sr, K, Rb, Ba) and LREE (e.g., Ce), but depletion in HFSE (e.g., Ta, Nb, Ti, Zr, Hf, Y) and HREE (e.g. Yb). The Shahre-Babak alkaline basalts show characteristics of subduction related (active) continental margins, OIB and within-plate tectonic environments. Regarding the Late Miocene collision time between Arabia and Central Iran, the Shahre-Babak alkaline basaltic lavas should be collision related (post-collisional). Their enrichment in LILE and LREE relative to Ta and Nb can be explained either by: (a) presence of a subduction component or addition of an LILE-enriched, Nb-Ta poor fluid component to the mantle wedge or (b) crustal contamination of mantlederived magmas during their ascent to the surface through assimilation and fractional crystallization (AFC) and or MASH (melting, assimilation, storage and homogenization). The magma erupted in a post-collisional tectonic setting and formed in a within-plate environment between two north-south running faults and is closely related to deep lithospheric fractures.

In the Asemi-gawa area of intermediate high-pressure and low-temperature Sanbagawa metamorphic belt in central Shikoku, Japan, piemontite-quartz schists are common in which cation exchange between piemontite and garnet has been studied. Piemontite in contact with garnet usually contains two zones in which core is enriched in Mn3+ and surrounded by a rim rich in Fe3+. Garnet is Ca-Febearing spessartine and is slightly heterogeneous in which core rich in Mn is surrounded by a narrow rim poor in Mn and rich in Ca. The chemical composition of piemontite changes in contact with garnet in matrix or whenever it is included in the garnet porphyroblast. In both types of contacts, piemontite tends to be richer in Mn3+ and poorer in Fe3+ while garnet tends to be richer in Ca and Fe3+ and poorer in Mn2+. P-T curves were calculated using piemontite-garnet equilibria and show that the chemical variation from core to rim in piemontite-garnet pair is related to increasing temperature whilst cation exchange in boundary of piemontite-garnet can be caused by decreasing temperature. Log ¦ (O2)-T calculations show that cores of piemontite-garnet pair have been formed under more oxidizing condition than their rims. Calculations also show cation exchange between piemontite and garnet has been occurred under more oxidizing condition than the piemontite-garnet rim.

The statistical analysis of spatial data is usually done under Gaussian assumption for the underlying random field model. When this assumption is not satisfied, block bootstrap methods can be used to analyze spatial data. One of the crucial problems in this setting is specifying the block sizes. In this paper, we present asymptotic optimal block size for separate block bootstrap to estimate the variance of sample mean for spatial lattice data, using minimization of asymptotic mean square error of the estimator. Further, an empirical method has been proposed to determine the optimal block size. Also the optimality of the empirical estimate of block size has been considered numerically in a simulation study.