Journal of Sciences, Islamic Republic of Iran
Volume:15 Issue: 2, Spring 2004

Down syndrome is one of the most common causes of mental retardation observed in approximately 1/700 live birth. The use of two or more STR markers related to chromosome 21 facilitates the diagnosis of Down syndrome within about six hours from the collection of the samples. This is the first study has been performed in Iranian population to assess the diagnostic value of using small tandem repeat (STR) markers assays for the rapid detection of chromosome 21 trisomy and compare its application to the conventional cytogenetic analysis. Eighty seven cases with Down syndrome and 120 normal controls have been tested by conventional karyotyping and molecular technique using five STR markers (D21S11, D21S1414, D21S1440, D21S1411, D21S1412) located on the long arm of chromosome 21. The heterozygosis of these tested markers has been calculated in tested Iranian population. All tested cases had free chromosome 21 trisomy in cytogenetic analysis from them 3 cases were mosaic for chromosome 21 trisomy. In molecular analysis 85% generated three allelic pattern, 14% dialleilc and 1% monoallelic pattern by using five molecular markers. Diagnosis of chromosome 21 trisomy was achieved for 99% of cases by molecular method, from them 3.5% of cases were mosaic and provided diallelic pattern. We have found a specificity of 100% and sensitivity of 99% for molecular diagnosis of Down syndrome using highly polymorphic STR markers. This technique is cheaper, quicker, no need of alive or sterile samples and useful for wide screening of newborns in nurseries. Molecular method accurately determines trisomy 21 especially when cytogenetic approach is not suitable in the case of fixed or dead tissues, small number of cells such as those taken from early amniocentesis or cells separated from maternal blood for noninvasive prenatal diagnosis. Although molecular diagnosis of Down syndrome targeted specifically to chromosome 21 trisomy but it can exclude the presence of the most frequent chromosomal disorder. The result of this investigation has documented the diagnostic advantages of this approach to perform even for prenatal test or in parallel with cytogenetic analysis.

In order to investigate the effect of different geographic origins of pollen grain in intraspecific hybridization and to achieve hybrid vigor, artificial hybridization has been carried out between different local genotype of Populus euphratica Oliv. using conventional and embryo-rescue techniques. Because of long period requirement for Populus euphratica Oliv. embryo development, as a maternal plant, 45 day old pollinated catkins were used for ovary and ovule culture. For embryo germination, isolated ovaries and ovules were transferred to different kinds of media (MS, Half-MS and DKW). The mean effect of pollinated Populus euphratica Oliv. ovaries was 34.03% to produce plantlets, whereas the value for pollinated ovules was 47.46%. There was a significant difference between ovaries and ovules for embryo germination at 0.05% level. In spite of no significant difference between media for embryo germination, the highest percentage of embryo germination was observed in MS medium (43.22%). Due to existing of high number of ovule in each ovary (15-30), the highest number of plantlet was observed in ovary culture. No significant differences were observed between pollen grains with different origin (geographic origin) in percentage of fertilization and embryo germination. Morphological variation was observed among regenerated plants. One hundred thirty seven plantlets were successfully acclimatized in a green house and transferred to the field

The anthocyanins of Siahe Sardasht variety (Vitis vinifera L. var. S.S.) were extracted from freezed samples and were purified by adsorption on cation-exchange resin column. Individual pigments were separated by TLC on cellulose plates. Monomeric anthocyanin content that was determined by pH-differential, was 1740.11±3.58 mgL−1 (based on malvidin 3-glucose). Five major pigments were identified by 1H-NMR, IR and UV-Visible spectroscopies. All pigments were acylated with acetyl groups and three of them were acylated with malonyl groups.

Rhodococcus FMF is a gram-positive bacterium isolated for the first time from soil samples of Tabriz refinery in Iran. This microorganism is able to catabolize dibenzothiophene to 2-hydroxybiphenyl and inorganic sulfur without the destruction of carbon-carbon bonds. Three structural genes، dszA، dszB، and dszC have been characterized and shown to be responsible for this phenotype. In this work، dszC gene from Rhodococcus FMF was identified and then isolated by PCR technique using the nucleotide sequence of dszC gene from Rhodococcus erythropolis IGTS8 to design required primers. After amplification، the purified PCR product was cloned into plasmid vector pTZ57R/T. Further analysis by mapping and sequencing showed the identity of 689 nucleotides from this gene compared to the dszC gene from Rhodococcus sp. Strain IGTS8 as a key microorganism in biodesulfurization field.

Recombinant human erythropoietin is a glycoprotein hormone that stimulates erythropoiesis. In clonogenic assays of hematopoietic progenitors, high concen-trations of erythropoietin (Epo) increase CFU-E and diminish the number of granulocytes formed per culture plate. Fetal progenitors are more sensitive to these effects of Epo than progenitors from adults. We administered doses 50, 100, 200 IU/kg of rHuEpo, subcutaneously, twice a week for six weeks. rHuEpo recipients had elevations in RBCs and reductions in WBCs, and platelet count, as well as in spleen (p<0.05).

Reaction between 5-methyl-3-aminoisoxazole and ρ-acetamidophenylsulpho-nylchloride yielded compound 1. Hydrolysis of compound 1 gave a starting compound 4-methoxybenzal-ρ-5-methyl isoxazol-3-yl-sulphonamido aniline 2. The compound 2 on condensation with different aldehydes and potassium cyanide yielded the nitriles 3a-l. Cyclocondensation between oxazolinone and compound 2 yielded imidazolines 4a-l. All compounds have been characterised using IR, 1H NMR and Mass spectral data and have been evaluated for their antimicrobial activity against different strains of bacteria and fungi.

A simple and efficient procedure for converting a variety of 1,1-diacetates into the corresponding aldehydes was developed. The methodology has been done with zirconium sulfate tetrahydrate-silica gel as catalyst. The temperature plays an important role in these reactions. The phenolic acetate function can selectively be deprotected into phenol.

Substituted Schiff''s bases 2a-o prepared by the treatment of 2-amino-4-(α-methoxyiminocarbomethoxymethyl)-thiazole 1 with different aromatic aldehydes, on cyclocondensation with mercaptoaceticacid and mercaptopropionicacid in dry benzene furnished desired thiazolidinones of type 3a-o and 4a-j, respectively. The structure of the compounds have been assigned on the basis of elemental analyses and spectral data. The products were evaluated for their in vitro growth inhibiting activity against several microbes. Some of the compounds showed significant antitubercular and antifungal activity.

Amygdaloidal, cavity- and fracture-filling zeolites in Eocene volcanic rocks from the Kuh-e-Aradeh of southern Kahrizak, in the northernmost part of Central Iran have been studied in some detail by optical, chemical analysis, SEM, and XRD techniques. The zeolites identified, in order of their relative time of formation from early to late, are tetranatrolite, analcime, natrolite, mesolite, stilbite-Ca, scolecite and heulandite-Ca. Formation of zeolites in the studied region began with a sodium zeolite of low Si/Al ratio and, with the gradual increase in calcium content and Si/Al ratio, ended with calcium zeolites. The zeolites were probably formed as a result of the late-stage hydrothermal activity in 60-150°C spans. Other associated secondary minerals in the region are calcite, opal, quartz, and pyrolusite. Chemical analysis of the host rocks showed that they are mostly andesitic, or, to a lesser extent basaltic, and the composition of one zeolite-bearing dyke is potassic trachybasalt.

In this paper we consider C0-group of unitary operators on a Hilbert C-module E. In particular we show that if A⊆L(E) be a C*-algebra including K(E) and αt a C0-group of *-automorphisms on A, such that there is x∈E with =1 and αt (θx,x) = θx,x t∈R, then there is a C0-group ut of unitaries in L(E) such that αt(a) = ut a ut.

In this note some useful properties of strongly continuous two-parameter semigroups of operators are studied, an exponential formula for two-parameter semigroups of operators on Banach spaces is obtained and some applied examples of two-parameter dynamical systems are discussed.

A theory is presented for the dispersion relations of the nonlinear phonon-polaritons arising when phonons are coupled to the electromagnetic waves in multilayered structures of nonlinear materials. The calculations are applied to a multilayered structure consisting of a thin film surrounded by semi-infinite bounding media where each layer may have a frequency dependent dielectric function and Kerr-type nonlinearity. At least one of the media is an ionic crystal supporting optical phonon modes. The resulting analytic and numerical solutions for the dispersion relations of phonon-polaritons with s-polarization are considered for several cases. We find that the presence of nonlinearities leads to multiple branches in the dispersion relation. The results are plotted as frequency versus wave vector and frequency versus nonlinearity for different phonon-polariton modes. The parameters that modify the modes correspond to the in-plane wave vector, the thickness of the film, the phonon frequencies and the nonlinearity of each layer.