IRANIAN JOURNAL OF BIOLOGY
Year:2011 | Volume:24 | Issue:2|Papers Count:20

HEK (human embryonic kidney) 293 cells as transient transfection systems are the most useful expression method to study physiological and pharmacological properties of the GABAA receptor subunits. HEK properties are similar to the native expressed channels. In comparison to the other common artificial expression systems, HEK cells have a similar mammalian intracellular environment. Since some mRNAs such as GABAA g3 are significantly found in HEK 293 cells, caution must be taken in interpreting the results of studies of the properties of GABAA receptors expressed in HEK 293 cells. In this study we examined the endogenous mRNA content of GABAA receptor subunits a1, a2, g1 and g2 in HEK 293 cells using traditional PCR and real time PCR. Total cellular RNA was extracted from HEK 293 cells and reverse transcribed to cDNA. PCR and real time PCR reactions were performed in a 25 ml volume containing specific forward and reverse primers for GABAAR subunits with other required reagents. Reactions were carried out using a thermocycler. The amplification products were analyzed on 2 % agarose gels stained with ethidium bromide. In this study, none of GABAAR subunits in HEK cells were detected. The results show that HEK 293 cell line can be used as an expression system for the analysis of GABAA receptor recombinants.

The non-conventional yeast Yarrowia lipolytica produces several lipases. Lipase enzyme is one of the most important classes of industrial enzymes. Lipase is used in the production of detergents, cosmetics, pharmaceuticals, flavour enhancers and foods. Lipase production depends on media composition and environmental conditions. To select a suitable carbon source for high level of lipase production, Y. lipolytica DSM 3286 was cultured on different carbon sources. The highest lipase production was detected in medium containing Olive oil (34.6 U/ml) after 48 h in comparison with other used carbon sources. The results of this study are under development Y. lipolytica lipase production.

Soil samples of Tehran parks were screened for proteolytic Bacilli. 40 isolates were obtained from 5 soil samples, of which 18 isolates had the potential of producing proteases based on screening on skim milk agar. By comparing the diameter of clear zones, one of the isolates obtained from Lavizan park, in north east of Tehran, was selected for further experimental studies. This isolate was identified as Bacillus sp. CR-179 based on cellular morphology, gram staining, biochemical test, and finally partial sequence of 16S rDNA. Various nutritional and environmental parameters affected protease production by Bacillus sp. Protease production by this Bacillus cultivated in liquid cultures containing 1% starch as a carbon source and 0.4% corn steep liquor as a nitrogen source reached a maximum at 24 h, with levels of 340.908U/mL. Starch and maltose were the best substrates for enzyme production while some pure sugars such as fructose, glucose and sucrose could not influence production of protease. Among various organic nitrogen sources corn steep liquor, which is commercial, was found to be the best substrate followed by yeast extract, whey protein and beef extract. Bacillus sp. CR-179 Could not utilize urea as an inorganic nitrogen source to grow and produce protease. The optimal pH and optimal temperature of enzyme production were 8.0 and 45oC, respectively. Studies on enzymatic characterization revealed that crude protease showed maximum activity at pH 9.0 and 60oC, indicating the enzyme to be thermo-alkaline protease.

Durum wheat is one of the most important cereals that culture in the West of Iran in farm and dry land from long time. Recently, It was revised because of its high yield, adaptation to drought stress, dry and semidry climate. The study of genetic diversity progreses the program of plant breeding and conservation of germplasm. In this study 79 genotype of indigenous durum wheat from West and Northwest of Iran were used. The population using 10 primer combinations of SSAP analyzed .For determination of genetic diversity between population Na, Ne, H, I, A indices were used. Kermanshah had the most value in all of them, Ilam had the lowest Ne (1.3623) rate and Ardebil had the lowest Na(1.5753), I(.3270), H(.2229) and A(57.53%) value. Dendrogram constructed based on dissimilarity matrix from PopGene software using UPGMA algorithm in NTSYSpc software.

Xanthan is one of the most important industrial biopolymer which is produced by different strains of genus of Xanthomonas. In this study we use Taguchi experimental design for optimization of magnesium, iron, sulfur, nitrogen and phosphorus sources in culture medium of native xanthan producer strain b82 of Xanthomonas campestris which recently has been screened and identified. Our results showed that in optimal condition (phosphate source content with optimal concentration of 5.8 g/l kalium phosphate, magnesium source content with optimal concentration of 0.24 g/l magnesium sulfate, sulfur source content with optimal concentration of 2.8 g/l sodium sulfate, nitrogen source content with optimal concentration of 1.2 g/l ammonium chloride, iron source content with optimal concentration of 1.68mg/l ferric chloride) xanthan production was 16.11-21.45 g/l with Confidence degree 95%.In addition , we showed that concentration of magnesium source is key factor of xanthan production, although nitrogen source is more important for bacterial growth and iron source is the most efficient factor of viscosity production.

Xylan the major portion of the hemicellulose of plant cell walls are heterogeneous polysaccharides. Xylanases (EC:3.2.1.8) are enzymes obtained from different species of microorganisms that degrade the xylosidic linkages of xylan's backbone producing xylose with other monoresidues. In this study xylanase enzyme was purified from culture supernatant of Bacillus stearothermophilus (ATCC 12980) by ammonium sulfate precipitation, gel filtration on sephadex G-100 followed by ion exchange chromatography on DEAE-cellulose. In DEAE- cellulose column chromatography, three protein peaks F-1a, F-1b and F-1c were appeared. Among these peaks, only F-1b showed xylanase activity and the degree of purification attained 63.09 fold. The specific activity and purification fold of the purified xylanase was 87.7 U/mg of protein and 17.45, respectively. The enzyme gave maximum activity against xylan as substrate at pH 7.0 and temperature at 60oC. In paper chromatography xylose was detected as the hydrolysis products of oat-spelt xylan by the xylanase at 16 h. These results indicate that xylanase of Bacillus stearothermophilus (ATCC 12980) was endoxylanase. In conclusion, these data suggested that purified xylanase can be suitable for industrial applications.

Acetate kinase, an enzyme widely distributed in the bacterial and archaeal domains, catalyzes the phosphorylation of acetate. Acetyl phosphate is a precursor of acetyl coenzyme A and a potential regulator of bacterial signal-transduction. To gain some insight into the structure-function relationship of this enzyme, A variety of Gram-positive and Gram-negative bacterial acetate kinases, as well as a fungal and an algal sequences were chosen and three-dimensional structures were generated for each sequence. Only one structure (Methanosarcina thermophila) has been elucidated so far by X-ray crystallography, which was used as a template. These 22 sequences presented between 53 and 76% similarity with that of the template enzyme. An average of 50 models were generated and refined for each sequence with the use of MOD ELLER 9v2, and checked with Procheck and Errat programs. The best models were then compared using the Chimera software. The obtained structures presented a fold similar to that of the template enzyme, with an average RMSD (Root Mean Square Deviation) of 0.46 AO only small differences could be detected mainly in the N-terminal part, far away from the active site. These occur in the connecting segments of beta-sheets 3 and 4 or 4 and 5, or in the loop positioned after helix 1. The acetate binding pocket is completely identical between all models, with the exception of some proteins possessing a His residue instead of ASh (126 in Methanosarcina).This structural comparison of various acetate kinases showing a highly conserved fold ,could be of use in the design of this enzyme inhibitors, acting on a broad range of microorganisms.

To optimize in vitro propagation of Chrysanthemum morifolium Ramat, explants from auxillary and apical buds were cultured in MS medium supplemented with sucrose (30-40 gl-1) and different concentrations of cytokinin BAP (1-5 mgl-1). Proliferation of shoots from the segments of auxillary and apical buds of the mature plants and in vitro originated raised shoots were remarkably influenced by concentrations of the cytokinin and sucrose. Among different applied concentrations of sucrose and BAP, best response towards shoot proliferation from explants of mature plants were obtained in the media with sucrose (30 or 40 gL-1) and BAP (2.5 mgL-1 ) and from apical buds were gained in the medium with sucrose (30 gL-1) and BAP (1 mgL-1). Growth of in vitro shoot explants were significantly increased in the medium with BAP (1 - 2.5 mgl-1). The rate of micropropagation from auxillary buds of in vitro shoots was much more than that of the mature plant. Regenerated shoots were rooted in MS basal medium supplemented with IBA (2mgl-1). Obtained plantlets were transferred to the pots containing peat: perlit.

Salinity stress caused oxidative stress in plants by production of free oxygen radicals. In this study antioxidative (enzymatic and non-enzymatic) responses of three wild species of Solanum including S.acaule (salt tolerant), S.stoloniferum (salt semi-sensitive) and S.bulbosum (salt sensitive) to salinity stress were investigated In vitro. Explants were cultured in liquid MS medium (3% sucrose, without hormone) containing different concentrations of NaCl (0, 40, 80 and 120 mM). In S.acaule, shoot fresh and dry weight did not change by salinity. The activity of APX, PPO, SOD and GPOD were increased but CAT activity did not show any significant changes between control and salt treatments. In some concentrations of NaCl, the content of anthocyanin, falvonoids and phenolic compounds were also increased in this species. In S.stoloniferum, Salinity decreased shoot fresh and dry weight. The activity of APX, SOD and GPOD were increased by salinity but PPO activity was decreased. CAT activity did not show any significant changes between control and salt treatments. In this species the content of anthocyanin, phenolic compounds and one of the flavonoid compounds were decreased by salinity, while the content of other falvonoid compounds did not change by salinity. In S.bulbosum shoot fresh and dry weight was decreased, the activity of APX, SOD, GPOD increased, PPO activity decreased and CAT activity did not change by salinity. In this species the contents of anthocyanin and flavonoids were decreased in all concentrations of NaCl but phenolic compounds were only decreased in 120 mM NaCl. In conclusion, it seems that the comparison of enzymatic antioxidative defense system is not a good indicator for determining salinity tolerance in wild species of potato.

To evaluate the effects of methyl salicylate vapor on Catalase (CAT) and Ascorbate Peroxidase (APX) activity, Vitamin C content, ethylene production and decay index  of kiwifruit (Actinidia deliciosa cv Hayward) an experiment was conducted by five methyl salicylate concentrations (0, 0.06, 0.12, 0.18 and 0.24 mM) through five months shelf life period in 0.5 Co. The results of this experiment show that 0.24 mM methyl salicylate treated fruits had lowest decay percent in compare with control at the end of the shelf life period. The methyl salicylate vapor treatments in all of the exampling times caused alleviation in the activity of CAT and APX antioxidant enzymes and ethylene production, this inhibition effect was increased by induction in methyl salicylate concentration and the highest impact of methyl salicylate was assayed in 0.24 mM. Use of 0.24 mM MeSA led to slower reduction trend in Vitamin C content. In conclusion, 0.24 mM methyl salicylate treated fruits have had greatest effects on decay control, CAT and APX activities, ethylene production and Vitamin C content.

Due to investigation of plant diversity in ecosystem units, 268.7 ha-1 of lowland forest in Khanikan were studied. In order to investigate of plant covers sixty plots (20m × 20m for each) were taken by a systematic random sampled method. Five ecosystem units were classified using of TWINSPAN program. For analysis of plant diversity, Simpson, Shannon Wiener, McIntosh, Margalef, Menhenic, Peet and Hill indices had been used. Analysis of variance showed that ecosystem units had significant difference viewpoint Simpson, Margalef and Menhenic indices value. The other diversity indices hadn’t significant differences in ecosystem units. The maximum and minimum of Simpson index value were showed in 5th and 3rd ecosystem units, respectively. The highest value of Margalef and Menhenic indices devoted to 3rd ecosystem unit and the least value was showed in 1st ecosystem unit.  Plant diversity in ecosystem units are influenced of soil characteristics by reason homogeneity of slope, aspect and altitude in study area.

This research was accomplished during 2005 to 2006 at Weed Resaerch Department, Iranian Plant Protection of Research Institute for identification of morphophysiological variation of field bindweed population, and introduction of this weed biotypes in Karaj. The study was done by Principal Component Analysis (PCA) and Cluster Analysis (CA) based upon 43 morphological and physiological variables. Due to Karaj climate, The most important variables were shoot dry weight (SDW),(5.71-34.40 g) total biomass (10.56-36.91 g) and leaf area (557.56-1948.34 cm2), respectively. The results of this experience showed 11 biotypes in Karaj. The variability in morphological and physiological of these field bindweed biotypes may explain their different adaptability as the environmental conditions and different management practices change.

Rutilus frissi kutum is the most important bony fish inhabiting the Caspian Sea and is a very popular species among fishers, coastal dwellers and the people in Iran as well as in other Caspian littoral states for its high nutritive value and for its rich and good tasting meat. Blood indices are very important in fish physiology, the more knowledge of blood indices of fishes can be caused the more ability of breeding, culturing and restocking of them. This research was conducted amounts of ionic (sodium, potassium, magnesium and calcium) and metabolic (cholesterol, total protein and glucose) parameters in 35 maturated and 45 immature female Kutum blood in Guilan province, Sefid-rood river of southwestern Caspian Sea were determined. Fish samples were collected monthly from March to May in 2008. Blood samples were taken from the caudal vessels. No abnormalities or pathological changes in the ovarian or body of the investigated fish were detected. The results showed that Sodium, potassium, calcium and magnesium were maximum to minimum respectively and concentration of cholesterol was more than glucose and glucose was more than total protein in serum blood. There was a significant correlation between calcium and total protein in maturated (4.2±0.05 mmol/l, 3.1±19.6 mg/dl) and immature specimen (8.1±0.14 mmol/l, 4.1±18.7 mg/dl) (P<0.01). The differentiation between glucose with cholesterol in maturated (87.7±56.3 mg/dl, 475.3±64.2 mg/dl) and immature specimen (45.1±21.1 mg/dl, 347.3±95.1 mg/dl) was significant (P<0.01). No significant correlation between sodium and magnesium were be detected (p>0.05). According to influence of ionic and nonionic blood’s plasma on regulation of reproduction and growth in kutum, have an important role and can use in management of reproduction and culture of this valuable species.

Use of dietary supplements that can promote immune system function is one of the strategies in which not only provide essential nutrients to support growth and development of the cultured organisms but also may be one of the most promising means to influence the culture organism's health and resistance to stress and disease –causing agents. One group of health promoting compounds is referred prebiotics. Inulin a polysaccharide is a prebiotic that its health promoting function has been proved in human and mammals but little is known about its effect on fish. In this study fish were fed with trout commercial food that contained 40% protein, 14% lipid and estimated digestible energy level of 3.5 kcal/g. Inulin had supplemented in diet at 0.5 and 2% at weight. Each diet was fed to three replicate groups of Rainbow trout in P.V.C tanks and fish were fed twice daily to apparent satiation. After two month feeding 10 fish selected in each replicate and challenged with Streptococcus sp to test the effect of diet on disease resistance. Diet supplementation significantly stimulated serum lysozyme levels, total, IgM, and WBC (P<0.05). Also Lymphocyte numbers in fish fed inulin were significantly higher in comparison with control group (P<0.05). After 15 days of bacterial injection 15-20% of fish fed with 0. 5 and 2% inulin show disease signs (86% survival) but survival of control fish was only 65%. It conclude that inulin as prebiotic has positive effect on immune system in Rainbow trout and increase resistance against pathogenic bacteria Streptococcus sp.

The southern Iranian toothcarp, Aphanius dispar dispar, is a subspecies of cyprinodontids which is widely distributed in the Persian Gulf and Sea of Oman river basins. About 20 male and 20 female specimens of each 16 populations (610 specimens in total) were sampled. The samples were fixed in 10% formalin and gradually transferred to and preserved in 70% ethanol. Eleven meristic characters including dorsal, anal, pectoral, pelvic, caudal fin rays, gill rakers, lateral line scales and scales above and below the lateral line, circumpeduncle scales, and predorsal scales were counted on the specimens. Although significant differences (P<0.05) exist amongst 10 out of 11 characters (all but the scales above the lateral line), their wide overlaps preload them from differentiating the populations. Principal component analysis (PCA) could not differentiate the populations. It seems that these populations have not genetically enough isolated.