مجله علوم جمهوری اسلامی ایران
سال:1383 | دوره: | شماره: |تعداد مقالات:11

Calprotectin, a calcium-bound protein complex, is abundant in the cytosol of neutrophils. It has been reported that this protein has an apoptotic activity in tumor cells. Since calprotectin increases in colorectal cancer, this study was conducted to investigate, for the first time, the cytotoxicity/apoptotic effect of calprotectin on HT29/219 and SW742 colon carcinoma and adenocarcinoma cell lines. MTT (3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide) assay, annexin VIPI and Hoechst 33258 staining were used to detect apoptotic cells. The activation of caspase-3 and -9 was assayed using caspase assay kits. Flow cytometer was used to determine if there is any binding of calprotectin to its receptor. Treatment of the cells with different concentrations of human calprotectin resulted in a significant increase in the cell death. Annexin V/PI and Hoechst 33258 staining revealed that the cell death was mainly of apoptotic type. A significant (p<0.05) increase in the activity of caspase-3, and -9 was observed in both cell lines following the treatment. However no binding activity was observed. In Conclusion, this study showed that human calprotectin has an apoptotic effect on HT29/219 and SW742 cells, and that the mode of action is caspase activation particularly via mitochondrial route.

Soil salinity poses considerable and increasing problems for agriculture, and is receiving much attention from plant breeders. The identification of genes whose expression enables plants to adapt to and/or tolerate salt stress is essential for breeding programs, but little is known about the genetic mechanisms of traits in saline conditions. The data obtained from 75 families produced by crossing 25 F2 plants derived from a cross between two spring hexaploid wheats, namely Siete Cerros (salt tolerant) and Axona (salt sensitive), to their parents and their F1 progenies, was subjected to triple test cross analysis. The genetic components (epistasis, additive and dominance) and their interactions with the environment (control - salinity) were detected for heading date, days to maturity, final plant height, spike length, ear weight, straw weight, number of grains per ear, grain yield per plant, 1000 grain weight, whole plant weight and harvest index. Epistasis was presented only for days to maturity (j and 1 types) and plant height (i type) at control and spike length (j and 1 types) at salinity condition. Additive component (D) was more important than dominance (H) especially in salinity condition. Dominance ratio, (H/D)1.2,was less than unity in both environments and heritability (h2) decreased for all traits at salinity condition.

The Varicella-Zoster Virus (VZV) genome contains both eis-acting and transacting elements, which are important in viral DNA replication. The eis-acting elements consist of two copies of oriS, and the trans-acting elements are those genes whose products are required for virus DNA replication. It has been shown that each of the seven genes required for ori-dependent DNA synthesis of Herpes Simplex Virus type-I (HSV) has a homologue in the VZV genome. However these seven genes of VZV never supp.orted replication of the plasmid containing VZV oriS, in the same assay. On the other hand, several laboratories have shown that co-transfected cosmid DNAs containing the overlapping VZV fragments can supply all of the necessary functions for the VZV virion development. In the present study we found that the four overlapping cosmids are as efficient as virion in supporting the in vitro replication of co-transfected plasmids containing oriS. On the basis of these results, subcloning of each of the cosmids used in this system should allow one to identify all of the VZV genes required for DNA replication in cultured cells.

We studied the expression of human growth hormone (hGH) in E. coli under a bacteriophage T5-base promoter in a pQE30 expression vector. For an: efficient expression of hGH cDNA, a number of codons at the hGH N-terminal coding region were altered based on the E. coli major codons. An over-expression of hGH;in the bacteria, carrying the recombinant plasmids, was observed at 37°C in the presence of IPTG The over-expression was also observed at 30°C in the absence of IPTG. Therefore a temperature down-shift induction, 37°C to 30°C, was suggested to achieve an over-expression of recombinant hGH (rhGH) without the use of chemical inducers. The pQE30-hGH recombinant plasmids show high stability in the TG 1 host in the non-selective conditions. In a batch fermentation condition, the purified rhGH was obtained with the yield of 53 mg/l of culture. We took advantage of the formation of inclusion bodies to recover the rhGH, followed by diafiltration and refolding steps. The purified rhGH was biologically active for its receptor-binding on IM9 cells.

A hydr:metallurgical study based on the extraction of Zn and Pb from a NigeriaIl sphalerite mineral leached with 4 M hydrochloric acid has been undertaken. Triphenylphosphite (TPP) has proved to be very effective for the extraction of zinc. With 2 M TPP and at ambient temperature of 25±2°C;35.71% and 66.7% of Pb and Zn were extracted, respectively, into the organic phase within 60 min. The recovery rates of 93.27% and 91.16% from the organic phase were obtained after de-extraction with 6 M HCI for Pb and Zn, respectively. Finally lead has been successfully separated from zinc by the cementation of the former with zinc metal. The mechanism of extraction appeared to be chelate formation and ion exchange.

Zeolite ZSM-5 presents a great source of interest in catalysis because of its shape selective properties. The absence of a relationship between the template size and shape of the structure generated during the synthesis of zeolites is illustrated by the case of ZSM-5. In this study, we have investigated the role of ethanol, methyltriphenylphosphon-ium bromide (MTPBr) and cetyltrimethylammonium bromide (CTABr) as neutral and cationic templates on aluminosilicate zeolite formation. Ethanol was also successfully used as a low cost template in the synthesis of ZSM-5. Although the XRD pattern of the synthesized zeolites is similar to the ZSM-5 pattern, the SEM results showed that their morphologies are completely different.

Isoxazole (2a-l) and cyanopyridine (3a-l) derivatives have been prepared by condensing chalcones (la-I) with hydroxylamine hydrochloride and malononitrile respectively. While compounds la-l have been synthesized by the reaction of p- (3 -chloro-2 -benzo(b )thiophenoylamino )-acetophenone with different aldehydes. All the compounds were screened for their antitubercular and antimicrobial activities.The structuresof newly synthesizedcompoundswere establishedon the . basis of elemental analyses, IR, HNMR and " Mass spectral data.

Graft copolymers of acrylamide on carboxymethyl cellulose (d.s 0.4-0.5) were prepared by the use of ceric ion, ceric ion/reductant molecule initiator syst~ms in aqueous_medium. The graft copolymers were characterized by IR spectroscopy. The extent of graft copolymerisation was measured in terms of grafted chains as a function of both ceric ion and ceric ion/reductant molecule concentrations. It was found that introduction of reductant molecule resulted in up to 13 fold increase in percent graft levels. Flocculation of the copolymer samples and ungrafted carboxymethyl cellulose were studied using synthetic effluent of Kaolin (0.25%) in distilled water. The flocculation capacity measured in terms of reduction in the turbidity was found to be highest for carboxymethyl cellulose-g acrylamide and was dependent on the number and molecular size of the grafted polyacrylamide.

Molluscicidal activity of different organic solvent extracts of latex of Euphorbia pulcherima and Euphorbia hirta(Family-Euphorbiaceae) against two freshwater harmful snails Lymnaea acuminata and Indoplanorbis exustus has been reported. Both the snails are the intermediate hosts of Fasciola hepatica and Fasciola gigantica,. which cause endemic fascioliasis in cattle and livestock of Eastern part of India. Toxicity of all the extracts of both the plants was time as well as dose dependent against both the snails. There was significant negative correlation between LC yalues and exposure periods. Thus, the LC values of latex of Euphorbia pulcherima of chloroform and carbon tetrachloride extracts were decreased from 0.51 mg/L (24 h) to 0.24 mg/L (96 h) and 0.51 mg/L (24 h) to 0.21 mg/L (96 h) respectively, against Lymnaea acuminata and from 0.46 mg/L (24 h) to 0.11 mg/L (96 h) and 0.49 mg/L (24 h) to 0.17 mg/L (96 h) against Indoplanorbis exustus. Similar trend was also observed in case of Euphorbia hirta of all the solvent extracts. The doses that can be used for killing the 90% population of snail Lymnaea acuminata are safe for non-target fish Channa punctatus, which shares the habitat with these snails. We thus believe that further purification of active compounds present in Euphorbia pulcherima and Euphorbia hirta latex may eventually be of great value for the control of harmful snails and other aquatic pests.

Coarse-grained soils of Tehran are cemented. These soils are heterogeneous not only in gradation and density but also in cementation. Due to this heterogeneity and the extreme difficulty in obtaining undisturbed samples, artificially cemented specimens using lime as the cementing agent are used to understand the effects of cementation on the shear strength parameters. A base soil with 45% gravel, 49% sand and 6% fine material was used, based on gradation curves of the coarse-grained soils of Tehran. Specimens were prepared by mixing the soil with 1.5, 3, and 4.5 percent lime and after curing were tested using triaxial compressign tests. Specimens were also tested in uncemented and destructured conditions. The results of the tests indicated that the cementation increases peak shear strength, suggesting an increase in cohesion. Cemented specimens show a brittle failure mode at low confining pressure with a transition to ductile failure mode at higher confining pressures. The stress-strain curves for cemented specimens show a clear peak stress followed by a sudden drop in stress and strain softening. There is no clear peak in shear stress for uncemented and destructured specimens. The failure envelope is curved for cemented specimens. The influence of cementation on the friction angle of the tested specimens is a function of confining pressure, and degree of cementing. The results show that the peak friction angle at low confining pressure increases with increasing cementation.

The purpose of this paper is to study the higher order asymptotic distributions of the eigenvalues associated with a class of Sturm-Liouville problem with equation of the form w" = (λ2ƒ (x) - R (x))w (1), on [a,b], where λ, is a real parameter and ƒ (x) is a real valued function in C2 (a,b) which has a single zero (so called turning point) at point x =x0 and R (x) is a continuously differentiable function. We prove that, as a classical case, the asymptotic form of eigenvalues of (1) with periodic boundary condition w (a) =w (b), w (a) =w (b) as well as with Semi-periodic boundary condition w (a) = -w (b), w (a) = -w .(b) are the same as Dirichlet boundary condition w (a) = 0=w (b). Wealso study the asymptotic formula for the eigenvalues of (l) with boundary condition w (a) = 0 =w .(b), as well as w (a) = 0 =w .(b) and w (a) = 0=w(b).