Journal of Sciences, Islamic Republic of Iran
Year:2001 | Volume:12 | Issue:2|Papers Count:12

The use of in vitro potato shoot cultures for protoplast isolation is desirable for consistent protoplast qualities. Ethylene build-up in the culture vessels causes problems for leaf growth (e.g. decreasing leaf surface, dry weight and chlorophyll) in shoot culture. Fifty to one hundred یM Silver thiosulfate (STS) produced a larger leaf area as a source of plant material for protoplast isolation. STS also decreased the internode length of potato shoots but increased dry weight and chlorophyll. Regenerated plants were obtained from cultured protoplasts in a series of media based on the MS medium. Protoplasts of Delaware showed a better response in cell division and colony formation in agarose-solidified culture medium. Regenerated plants showed some degrees of aneuploid but basically were similar to the original potato plants.

The tribe Sophoreae sensu Polhill [9,10] is a large and diverse assemblage comprising the ancient and primitive ancestral stocks of Papilionoideae. The most frequent chromosome basic numbers in this tribe are x = 11 and x = 9 but chromosome numbers range from x = 8-14 are also known. In this study chromosome numbers and karyotype variation of Iranian members of tribe Sophoreae are reported. Iranian taxa in the Sophoreae are Sophora alopecuroides ssp. alopecuroides L., S. alopecuroides ssp. tomentosa (Boiss.) Yakovlev, S. pachycarpa Schrenk ex C.A. Meyer, S. mollis ssp. griffithii (Stocks) Ali, S. mollis ssp. mollis Graham, Ammothamnus lehmanni Bunge and Ammodendron conollyi Fische. S. alopecuroides and S. pachycarpa are 2n=36 and exhibit wide variation in chromosome size within karyotypes. The other taxa are 2n=18. The two subspecies of S. mollis show relatively little variation in chromosome type within the karyotype. Ammodendron conollyi had the smallest mean size of chromosome and Ammothamnus lehmanni had the biggest mean chromosome size. The significance of these results in relation to the evolution of the group and in comparison to some previously reported results is discussed. These results agree with Goldblatt’s count for A. lehmanni and A. conollyi and also agree with Jahan’s count for S. m. ssp. griffithii and another taxon was reported for the first time.

Leishmanolysin is a worldwide disease that is caused by different species of the genus Leishmania. Leishmanolysin, One of the genes expressed by Leishmania, appears to be an ideal candidate for genetic vaccination. In this study, a full length sequence, which encodes Leishmanolysin functionally critical regions (amino acids 100-579), was cloned from a Leishmania strain endemic to Iran. Analysis by restriction enzyme digestion and DNA sequencing in pUC 19 based T-Vector showed that the cloned gene contained the conserved segments of the Leishmanolysin. The identified segments in predicted protein sequence of our clone contained the important domains that have been known to function at the attachment and internalization steps of the parasite life cycle. The cloned gene was expressed in human transformed muscle (Rhabdomyosarcoma TE671/RD) and African green monkey epithelial (COS-7) cell lines under cytomegalovirus (CMV) promoter, and the expressed protein was detected by enzyme linked immunosorbent assay. Thus the cloned gene may be used as an active component of a naked-DNA vaccine against Leishmaniasis in the geographic areas endemic to this parasite.

A simple and sensitive high performance liquid chromatographic method with electrochemical detection is described for the quantitative determination of the amoxycillin and clavulanic acid in pharmaceutical dosage forms. Separation of sample components occurs on a reversed phase C18 column with a mobile phase consisting of methanol-water-phosphate buffer. For the amperometric detection, the potentials of +1.180 and +1.250 V were set on the working electrode for amoxycillin and clavulanic acid, respectively. High linearity over a concentration range of (25 ng to 250 ng, r = 0.998) and (31.25 ng to 1 mg, r = 0.999) was observed. This method is convenient and reproducible for analysis of these two components in different dosage forms.

Quantitative determination of Bronsted acid sites in acidic mordenite samples with varying proton concentrations has been studied using aqueous conductometric titration method. Conductometric titration of the ammonium form of mordenite with sodium hydroxide is feasible and the results indicate potential number of Bronsted acid sites. However, Bronsted acid sites concentration in acidic mordenites, measured by this method, is less than that evaluated by ammonium-mordenite titration. Calcination procedure, to produce acidic mordenites from its ammonium form, reduces Bronsted acid sites by dealumination and dehydroxylation processes. In conductometric titration, only accessible Bronsted acid sites are titrated and extra-framework aluminum species, which are generated during calcination and reside in the structure, are not titrated. This finding is supported by observing more reduction in the Bronsted acidity when higher temperatures of calcination are employed. Also, comparing diffuse reflectance spectra of the acidic mordenite before and after titration does not show extra-framework aluminum species reacting with added base. A negative linear correlation was observed between concentration of Bronsted acid sites measured by conductometric titration and the temperature of calcination within 450-750°C.

Oxidation of different types of 1,4-dihydropyridines with diphenylpicrylhydrazyl (DPP) and benzoyl peroxide (Bz2O2) as free radical oxidizing agents to pyridine derivatives is reported and a mechanism for this oxidation is also proposed.

This study attempts to investigate the origin of red pigments, time of reddening, and processes responsible for red colouring of the Upper Miocene age Upper Red Formation, the most important clastic unit in central Iran. Mineralogical composition and textural properties of the studied sequences show that the Upper Red Formation sequences were not red when deposited, although some parts of red pigments were derived from the source region. This study clearly shows that both detrital and diagenetic pigments contributed in red colouring of the formation but diagenetic forms were more significant.

The Kahnuj ophiolitic complex, a part of the Jazmurian ophiolitic belt, is located on the western boundary of the Jazmurian depression and is bounded by two major fault systems. There is a well-preserved, ophiolite pseudostratigraphy of early Cretaceous to early Palaeocene age and has a bearing on the Mesozoic development of southeastern part of Iran and adjacent region. The Kahnuj ophiolitic complex consists mainly of lava flows and pillow lavas with intermittent pelagic limestones, sheeted dykes, gabbros, and plagiogranites, with subordinate ultramafic rocks. Structurally, the complex is extensively faulted and fractured. The volcanic rocks have undergone low grade alteration and metamorphism, exhibiting greenschist facies assemblages. The basalts exhibit variable enrichment in LFS elements (Sr, K, Ba) relative to HFS elements (Ti, Zr, Y, Nb, P). The basalts are characterized by low Zr/Y (3.24-5.03), Th/Ta (1.29- 2.55), La/Nb (1.43-2.15) and Nb/Y (0.12-0.2) ratios, relatively low TiO2 and P2O5, and progressively enriched normalized patterns and increased Ce and Th values. Based on chemical discrimination parameters, the Dare-Anar basalts were originally developed in a back-arc basin and are representative of suprasubduction zone Tethyan ophiolites.

In this paper, for a complete lattice L, we introduce interval-valued L-fuzzy ideal (prime ideal) of a near-ring which is an extended notion of fuzzy ideal (prime ideal) of a near-ring. Some characterization and properties are discussed.

In this paper, we investigate a singular perturbation problem including a fourth order O.D.E. with general linear boundary conditions. Firstly, we obtain the necessary conditions of solution of O.D.E. by making use of fundamental solution, then by compatibility of these conditions with boundary conditions, we determine that, for given perturbation problem, whether boundary layer is formed or not.

As a sequel of the recent works, we would like to discuss another stage for the solution of the mixed problem which considers the concepts of well operated conditions applicable to the solution of mixed problem, i.e. the existence and uniqueness of the solution must always conformable with some assumptions.

The magnetisation and electron spin resonance (ESR) spectrum of two specimens of tetrahedral amorphous carbon (ta-C), deposited from a filtered cathodic arc, were measured over a wide temperature range. The magnetisation was found to consist of superparamagnetic, paramagnetic and diamagnetic contributions. The superparamagnetic contribution resembled that recently found in carbon prepared from the tetrahedrally bonded substance adamantane. We found that the superparamagnetic contribution in ta-C correlated with low-level ferromagnetic contamination and that the properties were well described by the classical Langevin function with a temperature dependent magnetic moment. ESR measurements combined with the magnetisation results for the paramagnetic contribution gave consistent values of the electron spin density which showed a very high level unpaired electrons in ta-C. This high spin density shows that a large fraction of the residual sp2 sites in ta-C are isolated in the sp3 network.