فهرست مطالب

  • No. 3103, 2008
  • A3
  • تاریخ انتشار: 1387/05/15
  • تعداد عناوین: 13
|
  • H. Sepehri, L. Delphi, Y. Rassouli Pages 223-229
    It is well known that several plant extracts have a lactogenic effect. This response may be induced through the stimulation of prolactin release from lactotrope cells. A partial purification of the active compound indicated that it is rich in pectin and b-glucan. These materials stimulate secretion of prolactin from hypophyseal fragments. In the present study, the effect of b-Glucan on the secretion of prolactin from GH3/B6 pituitary tumor cells has been investigated. These cells are good tools for studying the direct effect of b-glucan on prolactin secretion. The different concentrations of b-glucan (50, 100 and 200 µg/ml) increased secretion of prolactin within 24 hours of incubation in GH3/B6 media. Moreover, the secretion of prolactin was significantly elicited at 100 and 200 µg/ml of b-glucan incubation after 48 hours. These results suggest that b-glucan can affect the synthesis and/or release of prolactin, a hormone that plays many important physiological roles from GH3/B6 pituitary tumor cells.
    Keywords: Lactotropes, prolactin, GH3, B6 cells, b, glucan
  • A. Abbaspour, S. M. M. Moosavi, R. Mirzajani Pages 231-239
    A simple, rapid and sensitive spectrophotometric method has been proposed for the determination of Vanadium (IV). The method is based on the catalytic effect of V (IV) on the oxidation of Alkali Blue by potassium bromate at pH 4. The rate of decrease in the absorbance of Alkali Blue (at 572 nm) was proportional to the concentration of V (IV) in the range of 100-6000 ng ml-1. The detection limit was 40 ng ml-1. The proposed method shows a good selectivity for V (IV) over a wide variety of interference species. It is also valuable in that the presence of a 400 fold excess of V (V) can be tolerable, contrary to many methods for the determination of V (IV) which suffer from severe interference of V (V). This method was successfully applied to the determination of V (IV) in river water, alloy samples and several synthetic samples.
    Keywords: Catalytic, vanadium (IV), Alkali Blue, spectrophotometric
  • B. Alizadeh, M. H. Adabi, F. Tezheh Pages 241-253
    For this study, Asmari (Oligo-Miocene) and Bangestan (Cretaceous) reservoir oils from the Marun oilfield were studied geochemically. Gas chromatograms and stable isotopes of carbon and sulfur in different oil fractions were studied. Normal alkanes nC15+ are as high as 93% with a saturate percentage up to 53.9% which reveal a high maturity of Asmari and Bangestan reservoir paraffinic oils. Carbon Preference Index of both reservoir oils are around one, indicating mature oil samples. Pr/nC17 and Ph/nC18 ratios have confirmed this conclusion. The Pr/Ph ratio is less than one and the plot of δ13CAro.(‰) versus δ13CSat.(‰) both indicate a marine reducing environment during the deposition of their source rocks. The organic matter deposited in these sediments is of kerogen Type II (Algal). Stable carbon isotope results versus Pr/Ph ratio indicate that both oils originate from the same shaley limestone of the Mesozoic age. This study also proves that H2S gas polluted Asmari oils have a similar isotopic range as Bangestan reservoir oil, hence the source of contamination must have originated from the Bangestan reservoir. Isotopic and geochemical results, for the first time, introduce three oil families; two H2S polluted families and one non-H2S polluted oil family; in the entire Marun oilfield.
    Keywords: Marun, Asmari, Bangestan, Oil, Oil Correlation, GC, Carbon, Sulfur stable isotopes
  • H. R. Esmaeili, T. Hojat Ansari, A. Teimory Pages 255-262
    The normal and lateral line cycloid scales of a cyprinid fish Capoeta damascina (Valenciennes in Cuvier and Valenciennes, 1842) have been subjected to the scanning electron microscopy technique in order to study their detailed structure. The scales have the general morphological characteristics of the cycloid scales. In the normal scale located below the dorsal fin, the focus lies towards the anterior region and is covered by reticulate or honeycomb form structures with few mucous pores. There is a clear-cut demonstration between the anterior and posterior region. In the posterior section, the scale has several rows of pigmented granules (tubercles) with different shapes from round to oval, semi-oval and even oblong structure. On the dorsal side, the anterior circuli bear teeth-like structures called lepidonts which help the scale in firm attachment to the skin. The circuli may also have calcium projections. The lateral line scale has a canal which characteristically lies along the anterior-posterior axis, slightly towards the posterior part with two anterior and posterior openings. The anterior opening is wider than the posterior opening and is hidden by an evelike extension cantilevered over it. Based on the obtained results it could be concluded that the shape and size of lepidonts on the circuli crest and also the pattern of reticulate or honeycomb form structures in the focus region may provide reliable taxonomic tools.
    Keywords: Scale, scanning electron microscopy, lepidont, Capoeta damascina
  • M. B. Habibi, Najafi, B. H. Lee Pages 263-270
    The proline-rich b-casein was digested in vitro with trypsin, and the oligopeptides produced were then isolated by RP-HPLC and subsequently identified by amino acid analysis and ion mass spectrometry. The peptide fractions from the complete digestion were then treated with purified x-prolyl dipeptidyl peptidase (X-PDP) extracted from Lactobacillus casei ssp. casei LLG. Two bitter peptides (f53-97 and f203-209) containing X-Pro-Y-Pro in their amino acid residues were completely hydrolyzed by X-PDP, while several peptides with a high degree of hydrophobicity were also decreased in a peak area. The debittering effect of X-PDP from Lactobacillus casei ssp. casei LLG on enzyme modified cheese (EMC) was also investigated by both subjective and objective methods. The bitterness of cheddar cheese slurries supplemented with Neutrase® 0.5 L was completely eliminated after treatment with crude enzyme extract from Lactobacillus casei ssp. casei LLG. Two hydrophobic peptides in EMC with Ala-Pro-Phe-Pro-Glu-Val and Phe-Leu-Leu residues were hydrolyzed by crude enzyme extract. The RP-HPLC, and subsequently, ion mass spectrometry analysis have shown that the debittering effect on EMC was due partially to the presence of X-PDP.
    Keywords: Debittering, b, casein, enzyme modified cheese, X, Prolyl Dipeptidyl Peptidase, lactobacilli
  • J. Raheb, Sh. Naghdi, K. P. Flint Pages 271-279
    Electron transport system (ETS) activity was found to be related to the initial inoculum size, culturability and viability of E. coli. In this experiment, ETS activity of Flexibacter chinensis was measured by INT-method under a variety of conditions such as starvation media with different amendments and different temperatures. The relation between ETS activity, cell culturability, and viability was investigated. We found that the addition of glucose increased ETS activity without affecting cell culturability. Urea addition led to an increase in survival, but did not increase ETS activity.
    Keywords: Electron transport system (ETS) activity, starvation, Flexibacter chinensis
  • A. A. Sepahi Pages 281-289
    The study area is a part of the Sanandaj-Sirjan metamorphic belt comprising low- to high-grade regional and contact metamorphic rocks that are intruded by various plutonic bodies. Garnet crystals are abundant in pelitic schists, amphibole schists, migmatites, hornfelses and aplites. They are mostly almandine-rich (XAlm>60) pyralspite garnets and show dodecahedron, trapezohedron and mixed (dodecahedron-trapezohedron) forms. Garnets in pelitic schists have different forms, but in hornfelses and aplites they have a mostly trapezohedron form. Sometimes, in some layers adjacent to each other that have experienced equal pressure and temperature, observed crystal forms are various, which may be due to the changes in the chemical composition of the mineral and its host rock. Absolute temperature may not be so important for form variations but temperature gradients during crystal growth may have affected the crystal forms. In more rapid temperature gradients the trapezohedron form is more common, but in slow gradients the dodecahedron form is more common. Mn-rich/Ca-poor crystals have a pure trapezohedron form; Mn-poor/Ca-rich crystals have a dodecahedron form and others have mixed forms.
    Keywords: Morphology, chemistry, garnet crystals, dodecahedron, trapezohedron
  • M. Sharifi, M. Ghafori Pages 291-300
    The influence of the herbivorous snail (Physa sp.) on the algal periphyton community from the Gamasiyab River, Kermanshah province in western Iran was examined by establishing a gradient of Physa sp. density in artificial streams. The impact of Physa grazing was evaluated by measuring dry mass, ash-free dry mass (AFDM) and chlorophyll a in the periphyton community. Snails significantly depressed periphyton biomass. Following twelve days of grazing of the grazer densities of 0, 0.015, 0.03 and 0.06 individuals/cm2 the dry masses of the periphyton communities were 3.04, 2.9, 2.66 and 1.07 mg/cm2 respectively. Snails also decreased ash-free dry mass by 2.04, 1.78, 1.63 and 0.71 mg/cm2 and chlorophyll a by 8.6, 8.06, 5.25 and 4.6 mg/m2. During this experiment the survival percentage for 0.015, 0.03 and 0.06 (individuals/cm2) treatments was 77.7%, 58.3% and 30% respectively. During the 12 days of the grazing period in the artificial stream the snail growth also showed a density dependent pattern. Diatom biovolumes calculated in this study are 57.1×106, 36×106×31×106, and 5.8×106 μ m3/cm2 for snail densities of 0, 0.015, 0.03 and 0.06 individuals/cm2 respectively. A group of species which are found primarily in the grazed treatments include Achnanthes lanceolata, Cocconeis pediculus, and Ulothrix sp. In contrast, ungrazed assemblage had high relative abundance of non adnate diatoms such as Nitzcshia linaris, Gomphonema sp. and non filamentous chlorophytes such as Scenedesmus sp.
    Keywords: Periphyton, herbivorous snail, artificial streams, Gamasiayab River, Physa sp., diatoms
  • A. Tellioglu Pages 301-307
    Macrocyclops albidus and Cyclops vicinus are the two important copepods living in Hazar Lake. For this study, 50 females for each species were collected. Samples were taken between December 1999 and March 2000. Length (PL), width (PW), and height (PH) of prosome and length (UL) and width (UW) of urosome were measured in each female and subsequently, the following ratios PL/PW, PL/PH, PW/PH, PL/UL and UL/UW were determined. Volumes for M. albidus and C. vicinus females were estimated following the morphometric method Regression tests were conducted for both species between volume and prosome length or width. Regression lines were compared through covariance analysis. PL/UL was the best ratio for separating one species from the other. Average individual volume and standard error estimated for M. albidus and C. vicinus were 0.0063 (±0.001) mm3 and 0.0049 (± 0.001) mm3 respectively. Differences between both copepods morphometric variable and rate values were observed. Measured size and volume values increased in March and June compared with December. According to R2 values of regression lines, prosome width and prosome length were good volume predictors on different dates for M. albidus and C. vicinus. Differences in slopes and mean variances found between regression lines demonstrated variability according to different months.
    Keywords: Cyclops vicinus, females, Hazar Lake, Macrocyclops albidus, morphometric variables, volume
  • H. R. Ghasempour, E. Shirinpour, H. Heidari Pages 309-312
    Ferulago angulata (Apiaceae), a medicinal plant of western Asia, contains essential oils that are used as a food preservative. This study examined and compared the composition of leaf oil with seed oil and of the oils from two different habitats (one from Nevakov and the other from Shahoo). The oil yield from seed was 5-fold that from leaves (3.2%/100g compared to 0.63%/100g). Cis-ocimene was the major constituent of the seed oil from both regions (64.8% and 76.11%) and a prominent constituent (>20% of the total oil) of the leaf oils of both habitats. α-Pinene was the next main component (7-27%) of all 4 oils. Seed oils, with one major component (cis-ocimene), differed from the leaf oils, which were composed mostly of 3 components (α-pinene, cis-ocimene, & germacrene D). Distinctions between the oils of the two habitats were less marked than the leaf-oil/seed-oil differences; the cis-ocimene content was higher and α-pinene was less in both seed- and leaf-oils of the Shahoo habitats than the Nevakoh ecotype; trans-verbenol was absent from the Shahoo leaves, but reached a content of 5.8% in Nevahoh leaf-oil. Further distinctions were found in the content/presence/absence of 20-30 minor components of the oils.
    Keywords: Ferulago angulata, medicinal plant, essential oil
  • B. Haghighi, F. Falahati Pages 313-320
    Glucose 6- phosphate dehydrogenase from streptomyces aureofaciens was purified and inactivated by pyridoxal 5′-phosphate (PLP). The inactivation was a pseudo-first order and time-dependent reaction. Complete inactivation was achieved at 0.2mM PLP within 16 minutes. The type of inhibition was competitive with respect to Glucose 6- phosphate. Spectral characteristics of PLP-enzyme complex corresponded to the formation of a Schiff’s base between PLP and lysine residue(s) of the enzyme. Intrinsic protein fluorescence sharply decreased upon PLP modification with about a 10 nm red shift. The presence of glucose 6-phosphate in the incubation mixture prevented the fluorescence change. Fluorescence studies revealed that NAD+ and NADP+ binding induces different conformational changes in pyridoxylated enzyme. The stochiometry of PLP binding to the enzyme showed that 2 moles of lysine residues were modified per mole of enzyme. The data indicated that the modified lysine residues are involved in substrate binding and/or catalytic activity of this enzyme.
    Keywords: Glucose 6, phosphate dehydrogenase, pyridoxal 5', phosphate, essential lysine residue
  • M. Keshavarzi, M. R. Rahiminejad, M. Kheradmandnia Pages 321-324
    The genus Aegilops is one of the wheat relatives which comprise the main part of its gene pool. The identification of the Aegilops species is difficult due to their vast morphological similarities and gene flow among different species of Aegilops and cultivated wheat. Some morphological characters are used to distinguish different species in Aegilops. In this study, we evaluate all these characters and choose 9 quantitative morphological ones including culm number, reproductive culm number, the length of the longest culm, spike length including and excluding awns, length of longest inter-node, length of lowermost glume, and the length of the uppermost lemma and palea. These characters were measured for 64 populations of 10 species of Aegilops in Iran. Discriminative analysis was used to evaluate the correctness of classification. Results indicate a great confusion between two varieties of Ae. triuncialis, and these taxa as a whole with others. Discriminative analysis proved the diagnostic value of these 9 quantitative characters in Aegilops in Iran.
    Keywords: Aegilops, discriminative analysis, Iran
  • F. Rezanejad Pages 325-329
    Calcium crystals are evident in many parts of anther. There is little literature about differentiation of crystal-containing cells and crystal formation during anther development. Petunia hybrid grandiflora Flower buds collected at different developmental stages were fixed and studied. The results revealed that young anthers are tetrasporangiate and in each of the four corners, the primary parietal layer externally and primary sporogenous cells internally, arise from periclinal divisions of the archeosporial cells. In the young anther, septum and connective cells contain calcium crystals as druse. At stomium, there is an arrangement of a band of 8-14 cells just beneath the epidermis which densely stain and lack visible vacuoles. During the division of sporogenous cells and the formation of crescent shaped tissue, no crystals are seen in hypodermal cells. In this stage, druse crystals become larger in connective tissue. While meiosis is occurring, the hypodermal cells of stomium are elongated, yet crystals are not observable. During pollen development, hypodermal cells degenerate and sand crystals appear. It seems that these crystals result from druse crystal.
    Keywords: Anther development, crystal, containing cells, hypodermal cells, Petunia hybrid grandiflora