IRANIAN JOURNAL OF BIOLOGY
Year:2007 | Volume:19 | Issue:4|Papers Count:15

Trivalent chromium is an essential trace element in balancing human and animals' diet. Because of the role of this ion in carbohydrate and lipid metabolism, its deficiency causes appearance of diabetes symptoms and cardio-vascular diseases. For preventing chromium deficiency and undesirable effects resulting from using chemical supplements of Cr+3, chromium accumulator plants can be used as complementary food. For this purpose, effects of various concentrations of Cr+3 on growth and some mineral nutrients content in parsley (Petroselinum crispum) plants were studied. Parsley seedlings were grown on hydroponic culture (Hoagland) containing various levels of Cr+3 (0.1, 0.25, 0.75, 1, 1.5, 2 and 3 mg/l). After 5 weeks, the influence of Cr+3 on growth rate (root and shoot dry weight, root and shoot length and total biomass) and concentrations of Ca+2, K+, Na+ and P in roots and shoots were measured. Chromium accumulation was also determined in roots and shoots. Results showed that with increasing Cr+3 concentrations in medium, the root and shoot dry weights and lengths and content of mentioned mineral nutrients decreased. Significant decrease in the root and shoot dry weights were observed at 3 mg/l and 2-3 mg/lCr+3, respectively. Chromium caused significant decrease in the root and shoot lengths from 0.75 mg/l up to 3 mg/l. In high concentrations of Cr+3 (2 and 3 mg/l) Ca+2 content of the root and shoot decreased significantly. Significant decrease in K+ concentration in the root and shoot was observed at 3 mg/lCr+3. Treatments with 3 mg/lCr+3 caused significant decrease in Na+ concentrations of root. With increasing Cr+3 concentrations in medium, P content in the root and shoot increased that was significant from 0.75 mg/lCr+3 to 3 mg/lCr+3. With enhancing Cr+3 levels in medium, the concentration of this ion in the roots and shoots increased significantly. Chromium accumulation in the root was much higher than the shoots.

Fagus is one of the most abundant and economically important genera of woody plants in the North of Iran. Izozyme diversity of Fagus orientalis Lipsky was investigated in 14 Iranian beech populations originating from the major part of distribution range of this tree species in Hyrcanian zone (Southern coasts of Caspian Sea). Enzyme variation of beech populations was studied using 5 isozyme Loci at 4 systems including Phosphoglucose Isomerase (PGI), Phosphoglucomutase (PGM), Shikimate dehydrogenase (SKDH), 6-Phosphogluconate dyhydrogenase (6PGD) by starch gel electrophoresis. Among 19 observed alleles, 12 rare alleles in 5 loci (less than 5% of the allelic frequency) and 10 specific area alleles (observed in less than 5 populations) were detected. Results indicated that all specific area alleles are rare ones too. Population Neka at elevation 900 m from sea level and Kheirud at elevation 2000 m from sea level showed the highest number of specific area and rare alleles. No area specific or rare alleles were found in population Gorgan at 2000 m from sea level. Observation of some geographical trends in alleles PGI-B/B and SKDH-A/B were couse of important ecological differences among the studied populations (from East far to West far and from lowest to highest limitation of beech forests in Iran).

The purpose of this study was to investigate flora and plant species diversity around protected area of the Bazangan Lake. It is located in North-East of Mashhad with the altitude of 860 m.a.s.l. and between the longitude of 290 56' and latitude of 360 18'. The total area is 102 ha. The results of field investigation were collection and identification of 112 plant species belonging to 96 genera and 35 families. Compositae, Gramineae, Cruciferae and Umbelliferae were the most abundant plant families of the area. Raunkiaer's Life form spectrum showed that 57% and 28% of the species were therophytes and hemi-cryptophytes, respectively. Chorological characteristics of the plant species showed that more than 50% and 30% were of Irano- Turanian and Irano- Turanian/Euro- Siberian chorotype, respectively. The collected data were subjected to analyses by specific diversity packages to characterize and obtain numerical indices of species diversity and its components.

Salicylic acid (SA) or orthohydroxybenzoic acid and other compounds which are  belong to this group are plant phenolics that play a major role in regulation of many physiological processes e.g. growth, development, ion absorption and germination. In this study, the effects of salicylic acid (0.1, 1, 1.5, 2, 2.5 and 5mM) on seed germination of Brassica napus were investigated. 20 seeds were transferred on whattman paper inside of each Petri dish. All Petri dishes were incubated to germinator. The condition of germinator was: 16h day light and 8h dark period with 230C and 160C respectively and the humidity condition inside germinator was 58%. Germination percentage and the rate of germination were measured up to 5 days. Triton X-100 was used as surfactant for either control or treated plants. For drought treatment, solutions of polyethylene glycol 6000 were prepared with water potential 0, -0.4, -0.6, -0.9and -1.1 Mpa. 6 levels of ethylene treatment were applied (0, 10, 30, 50, 70, 90 ppm). For interaction effects of salicylic acid on drought stress, 4 levels of salicylic acid (0, 1, 1.5, 2 mM) and 3 levels water potential of (0, -0.4, -0.6 Mpa) were investigated. The seeds were treated for 2 days in salicylic acid and therefore 3 days in polyethylene glycol 6000. For observation of interaction effects of ethylene on salicylic acid and ethylene on drought stress, 4 levels of salicylic acid treatment (0, 0.5, 1, 1.5 mM), 3 levels of ethylene in (0, 10, 50 ppm) and 3 levels of water potential (0, -0.4, 1.1 Mpa) were applied.  Results showed that the percentage of seed germination was reduced significantly in treated seeds with salicylate when compared with control. However, osmotic stress did not effect on germination percentage but seed germination rate reduced significantly. Interaction effect of salicylic acid and ethylene on seed germination was significant as well as drought stress. Mean of the required for day germination isn't sometimes applied for calculation of germination rate. Therefore, we suggest that the sum of instantaneous velocity used germination rate calculation. Priming with salicylic acid is advisable to be done in low temperature. Treatment with ethylene reduced negative effects of salicylic acid and drought stress on seeds germination, thus we suggest ethylene can be used for better germination.

The genus Secale (Poaceae, Triticeae) was described first by Linnaeus. Based on the latest taxonomic treatment the genus contains three species, four subspecies and two varieties. Secale taxa are naturally occurring in Mediterranean areas, Eastern Europe to central Asia and South Africa. This study concerns the evaluation of taxonomic value of morphological characters and phenetic among Secale taxa in Iran. Our statistical analyses were done using the software STATISTICA. The resulting data matrix used for cluster analysis and Factor analysis. The results of this study showed that there is no diagnostic morphological character among the studied populations of Secale. The homogeneity of the morphological characters can be caused by gene flow and hybridization in this taxon, limited the taxonomic value of such traits. Based on the results of this study it can be concluded that there is a little possibility for effective separation of Secale species based on morphological characters.

In this study the interaction of antitumor antibiotic, daunomycin with histone H1 in different ionic strengths was investigated employing UV/Vis and fluorescence spectroscopy. The results show that binding of daunomycin to histone H1 reduces protein absorbance at 210 nm and the amount of denatured protein is dependent on drug concentration. By increasing drug concentration, binding constant is increased whereas denatured free energy is decreased. Increasing the ionic strength intensifies the effect. Fluorescence spectroscopy also shows that the interaction of daunomycin with histone H1 reduces the intensity of the fluorescence at tyrosine position and produces hypochromicity. The results suggest that daunomycin binds to histone H1 and quenches tyrosine residue in the protein. In the chromatin, histone H1 can also be considered as a target for antitumor anticancer drugs.  

There are several methods for studying of microorganisms in the laboratory conditions that they mimic natural conditions. One of these methods is Gel Stabilized System. In this System microorganisms grow in the semisolid layer and form aria with very condensed bacterial population which appears like a Band and it is called Growth Band. Gel Stabilized System consists of two layers or phases that made of PYS Medium (Peptone Yeast extract Salt Solution Medium) with these differences: Glucose and 1.5% agar at the solid layer and 0.75% agar and certain number of bacteria in semisolid layer. H.pylori, L.plantarum and L.casei- casei grown in this system and produced Growth Band. The growth band formed in the condition of 2% Glucose to 10%, Different atmospheric conditions and height of semisolid phase, various agar concentrations and when the number of inoculated bacteria was over 10 × 105 /mL of medium culture. Ordinarily H.pylori formed 3 growth band and Lactobacilli 2.Three species are able to produce Growth Band in semisolid phase. The Growth Bands were formed depends on Glucose concentration, atmospheric conditions, height of semisolid phase and the number of inoculated bacteria but not to agar concentration in semisolid layers. We suggest for studying any substance or purpose is better the usage of a system with the following properties: 1) 2% glucose at solid phase 2) Aerobic atmospheric condition 3) 0.75% agar at semisolid phase 4) 50 mm semisolid phase height and 5) Number of bacteria inoculated over 3 × 105.

Expression, purification and comparison of fluorescence quenching in native and mutant bacterial luciferase at different concentration of FMN has been investigated. Bacterial luciferase consists of two- subunit a and  b. that are encoded by the LuxA and LuxB genes, respectively. Kinetic properties of bacterial luciferase are determined by a subunit. Bacterial luciferases catalyzes the light emission reaction (Wavelength 490 nm) utilizing FMNH2, fatty aldehyde and O2 substrates. Bacterial luciferases (Lux AB) can be readily classed as slow or fast decay luciferases based on their rates of luminescence decay in a single turnover assay. Recent studies using random mutagenesis on a subunit in the “slow decay” bacterial luciferase Xenorhabdus luminescence, showed one of the mutants contains Glu175 replacement by Gly has a significantly more rapid decay rate luminescence than native luciferase. Expression, purification and kinetic studies of native and mutant luciferase indicated that difference between native and mutant luciferase in luminescence decay rate may occur of weaker binding of FMN to enzyme in mutant luciferase.

Pullulanse is an enzyme that can be Produced by K.Pneumoniae, Bacillus acidopullulyticus and e few other Bacteria. This Enzme can brak pullulan biopolymer specifically and it is the most reliable method in this polymer detection. A suppernatant of K.Penamonia culture those cotains pullulanase used in detection and measurment of pullulan. At first, K.Penamonia was cultured in a preliminaty active nutrient agar containing pullulan (the enzyme specific substrate ) for 24 hours .Then 2ml of this culture was added to the 16ml of a culture media and it was incubated in 370 C and 120 rpm.The Enzymatic activity of this strain was determined at 5 hour intervals and the activity was seen after 10 hours the enzymatic activity of produced pullulanase measured according to released maltotrise in gram/lit, and 32.43g/l of maltotriose were release after 10 hours. The PH=5 and 400 C are the optimimum condition for enzymes activity.

Walnut is endemic to flora of the western part of Iran. Different insects and mites cause leaf deformation on walnut trees. In this study, three Eriophyeid mites were collected and determined, namely Eriophyes tristriatus (Nalepa), E. erineus Nalepa, and E. brachytarsus Keifer. This study showed that the E. tristriatus was dominant species in this area. Although, their damages have not economical importance. But in some locations, they cause considerable deformations of the leaves of walnut. The above mentioned mites have numerous natural enemies, such as Typhlodermus (Amblyseius) ketanehi (Dose), Kuzinellus kuzini (Wainestein), Paraseiueus jirofticus Daneshvar, Tydeus caryae Khanjani & Ueckermann, Anystis baccarum (L.), Orius minutum L., larvae of Feltiella acarivora (Felt), larvae and adult Stethorus gilvifrons (M.), Taeniothrips inconesquens Uzel., Thrips albapilosus Uzel. Amongst them Phytoseiid mites and T. carya have high population in this area and their efficiency was estimated to be about 14%. Their population reach to it’s highest intesity in September each year.

It is well known that D2 Dopamine receptors affect the feeding and drinking behaviours in mamallian, but there are a little data related to birds. The present work examines the possible role of Dopamin D2 receptor in the control of feeding, drinking and weight gain of young chicken in pigeons. This study was designed at 3 experiments; experiment 1: 8 adult male and 8 adult female pigeons (350-420g) were used respectively in a design of replicated 4×4 latin sequer in which, days and birds were the bloded factor. The animals were kept individual open air cages with ambient temperature (70° - 80°f) and a 12h light/ dark cycle. In each experiment, 0, 10, 20 and 40 mg/100g sulpiride, as a potent D2 Antagonist were injected subcotaneously. All solutions were injected at 2– day intervally, so that each bird received the solution during 7- day test period. Food and water intake were measured at 1, 2, 3 and 24h after injection, and the following results were obtained: sulpiride increased food intake in the females but not in males and increased water intake in the males but not in females 24h after injection. Experiment2: 40 female pigeons divided in 5 groups, group1 (solvent), group2-4, received Bromocriptin (Br) (0.5, 1, 2 mg/kg), group5 (No injection), the results showed that Br (2mg/kg) decreased food intake. Experiment3: 12 pair of parents received sulpiride during nestlings was 1 to 7 days of age and weight gain of nestling was calculated. The above findings showed that D2 receptors in pigeon as well as rat have a determinat role in feeding regulation, this receptors seems to increased weight gain of nestlings through crop sac secretio.

5- nitrofuran is one of the several drugs studied for its role on reproductive system. In this study the effects of nitrofurans: nitrofurantoin, nitrofurazone, and furazolidone were analyzed. During a 50– day period, adult male rats were given the drug via intrapritoneal injection. Thereafter male rats copulated with healthy females. The studied variables were the body weight, weight of tests and epididymis, hormonal assay, fertility and number of offspring. The results of this study showed no significant effects on the body weight and weight of tests and epididymis. Furthermore, a significant decreasing testosterone level was detected only in nitrofurazone and furazolidone treated groups. Also, fertility was not changed in any of the treated groups.Thus, short time exposure with these nitrofurans in low dose didn't affect fertility and only caused changes in levels of hormone.

The subject of this study was investigation of red blood cell alterations in diploid and triploid rainbow trout (Oncorhynchus mykiss). The triploid rainbow trout were obtained through the application of heat shock of 26.50 C for 20 min to eggs 20 min following fertilization. The diploids were not subject to shock. The 3n and 2n fingerlings of rainbow trout were reared under the same condition (environment, feeding). Fish ploidal level was determined by erythrocyte size measurement and gill nucleolus counting (NORs). Triploidy was 80.86% in heat shocked treatment. It was found that the percentage of erythrocytes with segmented nuclei in triploid fish was 13.52% and was significantly higher (P<0.01) than that in diploid fish (1.06%). In addition amitosis of red blood cells only seen in triploids (0.57%). It seems that increase of nuclear segmentation is one of the important characteristics for triploid rainbow trout.