JOURNAL OF SCIENCE (UNIVERSITY OF TEHRAN) (JSUT)
Year:2007 | Volume:32 | Issue:4 (SECTION: BIOLOGY 2)|Papers Count:23

Deregulation of Wnt signal transduction through the mutations to several components of this pathway, like adenomatous polyposis coli (APC) and b-catenin, has been reported in various tumor types. Here from 40 paraffin-embedded gastric adenocarcinoma and 50 paraffin-embedded esophageal squamous cell carcinoma tumor samples, genomic DNA was extracted and used as template for PCR amplification of exon 3 of the b-catenin gene (CTNNBI).By sequencing analysis of the PCR products, we detected five (12.5%) somatic missense mutations in gastric adenocarcinoma samples which three occurring at the regulatory GSK-3b phosphorylation sites. The other two mutations were adjacent to the phosphorylation sites. Among esophageal tumor samples, two (4.0%) had a missense mutation at codon 40 (a threonine), changing it to a glycine in one sample (T40G) and to an alanine in the other (T40A). We conclude that among Iranian patients, disruption of b-Catenin activity might play an important role in the development of a subset of gastric and a smaller subset of esophageal cancers.

With more than 1875 species known and new species being described each year, the Gobiidae is one of the largest families of bony fishes. In the Persian Gulf, these fishes, particularly those living in the intertidal zones, are little known. A study was carried out to investigate and identify the ichthyofauna of the harsh and stressful intertidal area of Qeshm Island, at the mouth of the Persian Gulf, at Hormoz Strait. During the study, amongst other fish species which will be dealt in another article, eight species belonging to the Gobiidae were identified and are hereby, reported for the first time from Qeshm Island. The species are: Acentrogobius dayi, Bathygobius meggitti, Coryogalops adamsoni, Cryptocentroides arabicus, Istigobius ornatus, Boleophthalmus dussumieri, Periophthalmus waltoni and Scartelaos tenuis. During examination of fishes, it was concluded that some of the species being reported from the area before, might have been misidentified.

Pollen morphology of 37 Astragalus species including 30 species of the section Malacothrix and 7 species from the related sections Hypoglottideii, Plagiophaca and Stereothrix was examined with light microscopy.Eleven species including 8 species from sect. Malacothrix and 3 each from the related sections were examined and photographed using scanning electron microscopy. The pollen grains are single, small, isopolar, tricolporate with the pores lolongate or circular at the center of aperture. The most common exine surface sculpturing is reticulate, rarely verrucate (only in A. laristanicus of subsect. Bornmuelleriana of sect. Malacothrix). Pollen shape ranges from spheroidal in A. sphaeranthus (sect. Stereothrix) to prolate in the remaining species studied. The current palynological data is of less taxonomic value to distinguish the studiedtaxa at both species and sectional level.

Qare-Qat (Vaccinium arctostaphylos L.) has an impressive history for treatment of diseases in Iran and other countries around of the world. Morphological characteristics, anatomical traits of stem and leaf using microscopic slides as well as its habitat climate were investigated using meteorological data. Also electron micrographs of seed were obtained using scanning electron microscope (SEM). Essential shoot oil composition was extracted by water distillation using clevenger apparatus. Twelve compounds were identified in essential oil. The major volatiles were hexadecanoic acid (27.0%), Vitispirane (6.5%) and Beta-ionone (5.9%).

There exist some differences between different strains of the nitrogen fixing bacteria in legumes tolerant to salt. Correct selection of bacterial strains resistant to salt can help increase the nitrogen fixation in soils. The study of negative effect of this factor in nitrogen fixation can help us in correct utilization of land. Study of the role of bacterial and plant cell cytoplasmic membrane which are part of the symbiotic process can help use symbiotic nitrogen fixation for increasing the yield. This study showed that within Lupine and Lucerna and their symbiotic bacteria there are a lot of differences in respect to salt tolerant levels. Lupine had 100 mM and Lucerna 175 mM concentration resistance in root growth conditions and their symbiotic bacteria Lupine tolerated 50mM .and Lucerna 400 mM (NaCl) in solid media conditions, respectively. No active transport to outside the cell through the cytoplasmic layer and their symbiotic constituents (Bacteroids, Cymbiocom) takes place and the salt resistant could be attributed to the intercellular compoundswhich cause osmotic pressure.

The use of low cost material especially agricultural wastes or by-products of food processing systems is an important factor in decreasing the costs of xanthan gum production. YMB (Yeast extract Malt extract Broth) is usually reported as preculture medium for production of xanthan gum, but its use in large scale (in primary and intermediary fermentors) is very expensive. In this lab-scale study, the possibility of using apple pomace infusion (API) as an alternative for YMB was evaluated.When API totally replaced YMB, the gum product and its viscosity were only 40% and 28% lower than that of YMB respectively. Comparing the yields obtained in YMB medium (11.73 g 11) and API (7.05 g 11) showed that the latter can not be considered as a sole substitute for YMB; but as a low cost substrate, it confers economical advantages. API with addition of nitrogenous compounds of YMB medium including yeast extract, malt extract and peptone resulted in higher gum production (10.8 to 12 g 11).Better results were obtained when peptone of casein (12.35 g/l), skim milk hydrolysate (11.4 g/l), ammonium phosphate (11.22 g/l), gelatin (11.1 g/l) and whey powder (10.6 g/l) were used. API plus the organic and inorganic nitrogenous additives as a low cost preculture medium can be used for the production of xanthan with suitable viscosity in food industry.

One hundred and forty eight bacterial strains were isolated from Anzali lagoon and Neidasht spring to determine selenooxyanions and tellurite reduction ability. Only one strain, identified and called as Bacillus sp. STG-83, was able to tolerate selenite and tellurite at high concentrations up to 640 mM and 1250 mM, respectively. The strain reduced the oxyanions. Morphological studies of Bacillus sp. STG-83, grown in presence of selenite, showed that the cells initially produced dark and condense granules at their surface and after 24 h they formed round bodies, but in the presence of tellurite the cells grew longer than their normal size. Bacillus sp. STG-83 was able to reduce 1 mM sodium selenite during 32 h but it reduced only 50% of potassium tellurite at 1 mM concentration after 104 h. Amount of elemental selenium in the precipitate was measured by Proton Induced X-ray Emission apparatus.The atmospheric gas of cultures was entrapped in gas washing bottle and then analyzed by Hydride Generation Atomic Absorption Spectrophotometery. The result showed that Bacillus sp. STG-83 was able to produce volatile compounds of selenium and tellurium.

Many microorganisms synthesize exopolysaccharides which either remain attached to the cell surface or are found in the extracellular medium in the form amorphous slime. We have studied the exopolysaccharide production from a new moderately Halophilic bacterium belonging to the genus Halomonas that isolated from oil well in Siri island in south of Iran. EPS production was assessed MY complex medium. The maximum EPS production was secreted in the presence of 7.5% (w/v) NaCl. The isolate was capable of producing EPS in the presence of KCl, Na2SO4 and NaNO3, with the results Na2SO4>NaNO3>KCl. The strain E1P1 grew and produced EPS on a variety of substrates. The potential of different carbohydrates in the EPS production was in the order: fructose> Sucrose> mannose>glucose>maltose. The maximum production of polymer occurred in MY medium plus 7.5% NaCl and 0.5% fructose at 45oC. The production of an exopolysaccharide began at the end of the exponential phase and continued during the entire stationary phase. This strain produced an exopolysaccharide at 138 mg l-1 with a maximum viscosity of 16 cp in MY medium. Viscosity of exopolysaccharide increased concomitantly with a decrease in pH from 7 to 3.

Production of extracellular protease was demonstrated under stress conditions of high temperature and high salinity by newly isolated moderate halophile, Salinivibrio sp. strain AF-2004 in basal medium containing peptone, beef extract, Glucose, and NaCl. Modified Kunitz method was used for protease assay. The isolate was capable of producing protease in the presence of sodium chloride, sodim sulfate, sodium nitrate, sodium nitrite, potassium chloride, sodium acetate and sodium citrate. The maximum protease production was secreted in the presence 7.5 to 10% (w/v) sodium sulfate or 3% (w/v) sodium acetate (4.6 U ml-1). Various carbon sources induced enzyme production. The pH, temperature and agitation optima for enzyme production were 9.0, 32 DC and 220 rpm, respectively. Maximum protease activity was exhibited in the medium containing 1% (w/v) NaCl. Its optimum temperature was about 60°C and the maximum activity obtained when reaction time was 5 minutes. Maximum activity of the enzyme was at pH 8-9 and its activity was inhibited by EDTA. This result suggests that strain AF-2004 produces an extra-cellular alkaline metaloprotease moderately thermo-tolerant and stable at high salt concentrations.

Heat shock protein 30 (HSP30) genes are conserved in their structural properties and are widely spread.HSP70 in Trichophyton rubrum is already detected and carefully characterized; however, no study was carried out for HSP70 in this pathogen fungus. In this survey, T. rubrum was obtained from patients with dermatophytosis and cultured in appropriate condition. High Molecular weight DNA has been extracted by using standard extraction methods.Pairs of 21 nt primers were designed from highly conserved regions of the same gene in other eukaryotic cells. Mentioned primers were utilized in PCR fragments were then sequenced. Finally, 415 nucleotides of HSP70 in this pathogen fungus were detected; which its ORF had 156 nucleotides and was coding 51 amino acids. This gene (called TrHSP30) is registered in Genbank at NCBI (NIH, USA) database. Detection of this gene may open the way to determination of its possible role in the pathogenesis of dermatophyte infections due to T. rubrum.

Root-knot nematode is one of the most successful and abundant parasites of a lot of plant families.This sedentaq' ne.matode induces the formation of feeding sites in infected root. Generation of these feeding sites causes cell and tissue changes that lead to gall and giant cell formation. Since tomato can be infected by all economical species of this nematode, in this research histological and ultrastructural changes in tomato root are studied. Comparing treated and healthy sections showed that nematode feeding sites comprised several giant cells adjacent to the vascular cylinder. Except in size, giant cells have some differences with other healthy cells.Their cell wall is thickened with the development of finger-like projections into the cell. An electron translucent layer is deposited on the inner surface of the cell walls, plasmodesmatal connections with other cells and neighboring giant cells are markedly reduced and walls of near cells growth greatly.Breakdown of the large vacuole gives rise to many small vacuoles. There are many enlarged amoeboid shaped nuclei in a giant cell. Concomitant to giant cell formation, hyperplasy and hypertrophy of the surrounding cortical cells lead to the formation of the typical root symptoms.

Control of microtubule nucleation is important for many microtubule dependent processes in cells.Gamma-tubulin is a universal component of microtubule organizing centers where it is believed to play an important role in the nucleation of microtubule polymerization. Gamma-tubulin also exists as part of a cytoplasmic complex whose size and com-plexity varies in different organisms. To investigate the distribution of gamma-tubulin in differentiated leukemia cells, HL-60 cell lines were induced to differentiate by All-trans retinoic acid (ATRA). We used pre-embedding immuno-gold electron microscopy and a monoclonal antibody against gamma-tubulin in undifferentiated and induced different-iated HL-60 cells. The results revealed that in un-differentiated cells, gamma-tubulin is mostly found in the pericenriolarregion, but in differentiated cells, besides the centriolar region, the amount of gamma-tubulin showed a significant increase in non-centrosomal regional of cytoplasm.These results suggest that the non-centrosomal gamma-tubulin complex plays a role in nucleation of microtubule in ATRA induced differentiated HL- 60 cells. Further, the cytoplasmic gamma-tubulin complex in different-iated cells is more abundant than undifferentiated cells.

Antimony and arsenic are toxic substances and are present in the environment as a result of natural processes and human activities. They are considered as a global poisoning and have been associated with different kinds of cancers and other symptoms. The aim of this study was to determine distribution and concentration of antimony (Sb) and arsenic (As) in Chelpo area. The collected samples (thirty six samples from twelve stations) were analyzed by using atomic absorption spectrometry. Concentrations of antimony and arsenic in the samples range from 11.4 to 108 mgl-1 and from 2.8 to 376 mgl-1, respectively. The concentrations are higher than what has been proposed by WHO (Sb, 6 mgl-1 and As, 10 mgl-1). These contaminants originate from weathering and alteration of rocks and leach into ground and surface water. The contaminations were higher in the sam-ples near the polluted area.However, the samples from pond with aquatic plants (such as macroalgae, Chara) showed lower concentration. The low con-centration of arsenic in the ponds is probably as a result of phytoremediation by the aquatic plant, but needs further investigations to reduce the contamination of water from these elements.

The rat pituitary cell line, GH3, and its subclones secret significant amounts of prolactin (PRL). The GH3/B6cells are generally grown in Ham's Fl2 medium supplemented with 15% horse serum and 2.5% fetal calf serum. In routine conditions, the doubling time of GH3/B6 cells varies from 30 to 52hr, depending on the qualities of the serum. The GH3/B6cells are used to study the effects of several hormones on prolactin secretion. The recent works have shown that pectic acid increases secretion of prolactin. Pectic acid releases stored prolactin in cells and after a short time it appears to be effective.After being incubated with pectic acid for 30 minutes the cells started to become circular, protuberant shape and entered the secreting phase. pectic acid had not significant effect in number of cells but a decrease in total amount of protein was observed. After pectic acid was added, a significant decrease happened in the medium pH and this decrease caused unfavorable condition for cells. To solve this problem, the medium with Hepes was used. Hepes had been used extensively in cell culture due to its excellent buffering capacity in the physiological range. After a while; however, the cells appearance changed, their growth decreased, cytoplasmics vacuoles and membrane inclusion bodies developed:and the viability decreased. Hepes stimulates the prbduction of toxic oxygen metabolites such as hydrogen peroxide which itself results in a decrease in growth of GH3/B6 cells. Consequently, Hepes was replaced by NaOH in this experiment NaOH had no effect on the cells and the pH was adjusted in 7.2.

In the present study, helminth parasites of 78 specimens of two sturgeons namely Acipenser persicus (N= 43) and A. stellatus (N= 35) from the south coast of the Caspian Sea were considered.Four parasite species were found including: Cucullanus sphaerocephalus (Nematoda), Skrjabinopsolus semiarmatus (Digenea), Leptorhynchoides plagicephalus (Acanthocephala), Eustrongylides excises (Larval Nematoda). Dominant species in A. persicus and A. stellatus are C. sphaerocephalus and S. semiarmatus, respectively. Shannon diversity index in A. persicus is significantly higher than A. stellatus. There are no significant differences between the prevalences, abundances and mean intensities of parasites in the males and females or different age groups. The results revealed that distribution of parasites in different microhabitats within gut is not related to intraspecific competitive exclusion.

In the peresnt study specimens of Capoeta capoeta and Chalcalburnus chalcoides from Shiroud River were examined for their digenean fauna. During this survey four digenean species including: Posthodiplostomum cutfcola, Diplostomum spathaceum, Clinostomum complanatum and Allocreadium sp. were found. The highest prevalence and abundance were observed in C. complanatum. The prevalence and abundance of C. complanatum in C. capoeta was significantly higher than Ch. chalcoides. In addition, variation of the prevalence and abundance with host sex and length group and also effect of parasites on host growth parameters were considered.Species richness, diversity, equitability, dominance, similarity, host specificity indices in two host species were studied. The results revealed that species richness, diversity and dominance indices in C. capoeta are higher than Ch. chalcoides. Discriminant analysis and specificity index confirm the high host specificity.

In this research, we have studied the remains of Ellobius of Kani Mikaeil cave associated with Calcaeolithic period (4000-3000 BC). A great number of microvertebrate remains were found after systematic dry sieving of the sediments from each section. The present paper tends to .identify the taxonomic con-ditions of the remains on the basis of morphologics and morphometrics methods and comparison with the modem species the amount of accumulation of the species (Ellobius lutescens and Ellobius fuscocapillus) in different layers.

Plants adapt different strategies in response to water deficit and salt stress. In the present investigation, stomatal resistance, soluble sugars, proline content and peroxidase enzyme activity of two species of Aeluropus littoralis and A. lagopoides was studied in response to these two stresses. A completely randomized factorial design with four replications and different combinations of four levels of water deficit (-0.3, -5, -10 and -15 bar), four salinity levels (0, 20, 25 and 30 dSm-1) and two species of Aeluropus were used under glasshouse condition.Water deficit was induced by weight method on the basis of the amount of water lost each day. For this purpose water potential of the soil used was measured by pressure plate method and on the basis of weight of soil in each pot and the associated water potential of the soil used was measured by pressure plate method and on the basis of weight of soil in each pot and the associated water potential of a soil, the amount of water needed for each treatment was calculated. In order to keep the water potential constant daily application of water was made on the basis of weight of each pot. Salt stress was made by addition of sodium chloride to the initial water applied. One month after stresses were imposed, two-weekly interval stomatal resistance recorded, and after two months soluble sugars, proline content and peroxidase enzyme activity were measured. Results showed that by increasing water and salt stresses, stomatal resistance was first increased and then started to decrease. Soluble sugars and proline content and peroxidase activity were also increased in response to both types of stresses. Interactive effects of salinity and water stresses were also pronounced.

Acidrain is one of the great importance stresses that are associated with atmospheric pollutions. This research tries to detect some effects of acid rain on the growth and microstructures of leaf surface. Bean plants were grown in plots in different groups and were treated by different acid solutions of HNO3, H2SO4 and both HNO3 and H2SO4. The pH of each groups regulated between 2- 4.5. Experimental plants were sprayed with different acid solutions and control plants sprayed by distilled water.Treatments were taken for 4 weeks, one in each day. Some growth parameters including dry weight, length of legumes, and number of seeds in each legume were compared in control and treated plants.Surface of leaves were studied by scanning electron microscope after coating with gold. Results showed that dry weight was decreased in plants under acid solutions. Decreasing of growth is considerable in treated groups by pH=2 solutions and HNO3 is also more effective regarding this effect. Number of Seeds were decreased in treated plants than control ones and decreasing of seeds is more considerable under H2SO4 treated groups. Microscopic effects of acid rain on leave surface showed that acid rain cause irregularity in epidermal cells, breakage of trichomes and separation of cells.