JOURNAL OF SCIENCES (ISLAMIC AZAD UNIVERSITY)
Year:2008 | Volume:17 | Issue:66/1 (BIOLOGY ISSUE)|Papers Count:18

The development of reliable processes for the synthesis of silver nanomaterials is an important aspect of nanotechnology today. There are few reports in literature on the biosynthesis of silver nanoparticles using microorganisms such as fungi. Here in this study, the production of silver nanoparticles by some microorganisms was investigated. The test strains were cultivated in their special conventional conditions for 24 hours. Silver nitrate at concentration of 10-3 M was separately added to the each reaction vessels that were contained the supernatants of Klebsiella pneumoniae, Escherichia coli, Enterobacter cloacae, Staphylococcus aureus, Bacillus subtilis, Lactobacillus acidophilus and Candidaalbicans. The silver nanoparticles were characterized by scanning electron microscopy and DV-visible spectroscopy. The silver nanoparticles were effectively produced, by Klebsiella pneumoniae, Escherichia coli and Enterobacter cloacae. We did not observe any extracellular biosynthesis activity from other microorganisms such as the Staphylococcus aureus, Bacillus subtilis, Lactobacillus acidophilus and Candida albicans in conditions tested during this investigation, this is the first report on the production of silver nanoparticles in enterobacteriaceae.

In this investigation effect of neutron radiation (Fast and Thermal Neutron) on root length, leaf surface, dry weight and chlorophyll of alfalfa were studied. Irradiation of both type of neutron (Fast and Thermal) for 120, 180 and 360 min resulted in different effects on growth parameters. Fast radiation had significant effects on chlorophyll and dry weight, while leaf area and root length were affected by thermal radiation. As a general conclusion, types of irradiation and duration of irradiation have different effects on growth parameters.

Artemia is a small crustacean that adapted to live in brine water and in unfavorable condition produce an embryo in gastrula state with tertiary shell that named cyst. The main source of Artemia in Iran is Urmia Lake, existence of two different groups Artemia urmiana cysts with different ability in buoyancy cased. This study was done to reveal structural difference between buoyant and sink cysts, role of shell layer in buoyancy or sinking, and relation between depth difference and shell layers thickness. Cysts of Artemia urmiana after collection from surface and bed for electromicroscopy fixed in glutaraldehyde and osmium tetroxide and dehydrated by graded series of ethanol and propylene oxide. Then, they embedded in resin (Agar 100) and 70-80 nm sections, and colored in two stages by uranyl acetate and lead citrate. Comparison between sections of surface and bed samples showed some differences in thickness of alveolar, 4.5 to 16mic and fibrous, 5.5 to 0.65mic Results showed structural differences, revealed shell layers are effective in buoyancy or sinking of cysts and against previous ideas about non-relation between buoyancy and shell layers thickness confirm that cysts set in different depths based on their thickness specially alveolar layer.

Tolerance and dependency are two main problems of drug abuse including morphine administration. It has been suggested that many drugs are involved in morphine induced psychological dependency. The current study was aimed to determine that, weather or not long-term intracerebroventricular (ICV) perfusion of testosterone enanthat could modify the acquisition of morphine-induced conditioned place preference (CPP) in adult male wistar rat. Male wistar rats (250-300gr) were anaesthetized with chloral hydrate (500 mg/kg, i.p.). Guide cannula was implanted in the right lateral ventricle using stereotaxic instrument. After one week recovery from surgery, rats subjected to subcutaneous administration of morphine, and long-term ICV perfusion of testosterone enanthat (21 mmin for 2 hours) using microdialysis probe and guide cannula. Biased method was used to determine the induction of Cpp in rats. Changes were monitored in all groups;and all statistical analysis were carried out using absolute data and one-way ANOVA.The present results indicated that subcutaneous of different doses of morphine sulfate (0.5- 10 mg/kg) produced a significant dose-dependent CPP in all experimental groups. The ICV perfusion of testosterone enanthate (2mg/kg) did not produce reliable CPP, however, longterm ICV perfusion of testosterone enanthate significantly modified the acquisition of morphine-induced (10mg/kg) conditioned place preference. Data from the present investigation suggest that testosterone enanthate influence morphine dependent euphoria and /or reward.

Aeromonas Spp. are oxidase positive, Gram negative bacilli that predominantly ound in surface waters such as lakes, rivers.Some species are responsible for a variety of human as well as marine animal diseases. They cause predominantly intestinal diseases as well as a few extra -intestinal complications. Aeromonas-related diseases often rise during natural disasters such as floods. In this study the occurance of Aeromonas Spp. in the flood waters of Golestan province in 2001 were investigated. For primary isolation, flood water samples were transferred into APW and blood agar media. following primary isolation, species identification was performed by biochemical tests such as oxiase, Lysin decarboxylase, Ornithine decarboxylase, Arginine hydrolase, Dnase, Bile esculin, Vogus proskeur, Simmon citrate, Indole, ONPG, growth in 0%,1%,6%salt solution and the string test. We were able to identify 27 case Aeromonas Spp. from a total of 60 water samples collected. The Spp included 21 A.hydrophilia isolate (77%), 3A.caviae (11%), and 3A.media isolate (11%).

Salvia bracteata is a permanent herb belongs to Lamiaceae family which wildely grows in some regions of Lorestan province. The aerial part of this plant was collected in postflowering stage from montains of North of Alashtar in Lorestan province. The air-dried samples were subjected to hydrodistillation using by Cleavenger apparatus for 2.5h ( in yield of 0.8%).The essential oil was analyzed by GC and GC/MS. Forty-six constituents representing 91.7% of the oil were identified. The major components of the oil were a- pinene (31.9%), myrcene(8.6%), limonene(8.1%), b-pinene(6.8%).

Anzali lagoon is the most important ecosystem which has a valuable role in culture and growth for aquatic animals of the southern Caspian sea basin. Molluscs are among the bentics habitant in this ecosystem, which in between, the bivalve Anodonta cygnea possessing a special role. Considering the importance of bivalves in food industry, medical activities, etc. Counting the bacterial colony of these aquatic animals, can be benefit for better usage of them.In this study, samples were collected in autumn 2004 and spring 2005 from Selkeh area which received water from south part of the lagoon basin. The reason for selecting Selkeh area for sampling was availability of this bivalve in this area during autumn. After sampling, live bivalves were transferred to laboratory and biometry was done and parameters such as length, width, height, total body weight and wet weight of internal soft part were measured. Then, bacterial colony counting was performed in soft body of this bivalve (as fresh and frozen) and also in the stomach. Counting the bacterial colony was done according to pour plate method.The results demonstrate that in autumn and spring, bacterial colony presented in stomach of this bivalve is more than fresh softbody and in fresh sampleswas more than frozen ones.The number of heterotroph bacteria in autumn and springwere 4´105 and 7´105 in each gr of soft body (fresh) respectively, and in soft body (frozen) samples 1´103 and in the stomach in autumn and spring were 7x105 and 9x105 respectively.These days, only the good quality and health of food items are important and should be tried to produce best quality products, which in this case we can present and active in world markets.

Hyoscyamus plants (Solanaceae) are tropane alkaloids producers. For investigation of tropane alkaloids levels within two Hyoscyamus species, H. arachnoideus Pojark and H. reticulatusL., plant samples were collected from natural habitats at three regions. Collection of plants was performed during vegetative, flowering and fruiting stages. After extraction and purification of alkaloids from different parts of the plants, levels of two tropane alkaloids, hyoseymine and scopolamine, were measured by high performance liquid chromatography (HPLC). Similarly, effects of some environmental factors on the alkaloids contents were investigatedin any regions. There was the highest level of hyoscyamine in leaves at flowering stage and of scopolamine in seeds, whereas stems were poorer in these alkaloids than other parts of plant. Hyoscyamine was dominant alkaloid, in different parts of the two species at various growth stages except in seed. Furthermore, hyoscyamine and scopolamine contents varied in different parts and various growth stages of these species, so that the highest levels of hyoscyamine and scopolamine were observed in roots, stems and leaves at flowering stage. R. arachnoideus Pojark contained more hyoscyamine and scopolaming than H. reticulatus L. at the three regions. The highest levels of hyoscyamine and scopolamine were observed in the plantscollected from Sephidekhan village. The results of investigation of some environmental factors effects on hyoscyamine and scopolamine levels showed that as altitude increased the level of the alkaloids in two species also increased. Furthermore, higher level of nitrogen and phosphorous in soil increased hyoscyamine and scopolamine levels in plants. Whereas, in contrast, lower level of potassium in soil increasedhyoscyamine and scopolamine levels.

Todays, population explosion, industrial development and environmental pressure caused destruction of habitats and biomes. A possible solution is application of knowledge of community ecology by the studying of species diversity. A glance to the related literature reveals a wide range of numerical indices used to characterize diversity of communities. But in order to prevent the problems that numerical indices create in diversity comparison, using other parameters is suitable. To obtain this aim, in this research it is used abundance distribution models, diversity ordering and rank - abundance distribution. In order to get a more clear-cut notion of the species abundance distribution of the sites, goodness of fit test were checked. In this study, two grazed and ungrazed area with the same climate, were selected. The results proved that diversity of ungrazed area was higher than the grazed one, because their profiles of diversity ordering were above the grazed site. The ungrazed site had a more flattened curve and the grazed site followed both log normal and logarithmic distribution and has shifted from lognormal to logarithmic model. They show an environmental disturbance factor dominates this grazing site.

Meanwhile the taxonomic research on the lichen flora of the Khorasan province, the identification key for 26 lichen genera related to 16 families has been designed on the basis of morphological and anatomical specifications, chemical tests and the structure of the vegetative substrate 12 lichen genera for the Khorasan province and 2 another genera including Farnoldia Hertel (1983) and Teloschistes Norman (1853) are newly reported for Iran.

Ageratum genus is a member of the Asteraceae family. Ageratum houstonianum is an ornamental plant which maintains essential oils. In this research anatomical studies of leaf, petiole, stem, root, rhizome and meristemes of stern and also tissue culture of some explants (apical meristem, epicotyls, hypocotyls, leaf, root and cotyledonary leaves) of plantlets in MS medium with supplement of IAA and Kin were investigated. The evaluation of quality of the calli and growing and regeneration of root, stern and leaf from the calli were used for assessment.The results showed that apical meristems of plantlets are the best explants in this condition for generation of plantlet. More over the concentration of IAA and Kin is very important to the quality of results, and these concentrations; IAA2/Kin4, IAA0.4/Kin1 and Kin1/AAI (mg.r-1) were more useful for this research to regenerate plantlets. The MS medium with Kin4/IAA2 (mg/1) was the best medium and generated the best plantlet, with longer survival than others.

In contrast to our wealth of knowledge on the antibiograms, there is a relative paucity of knowledge on the impact of different chemotherapeutics under various conditions.Commercially available fluoroquinolones are relatively new synthetic therapeutic agents which are used against g+, g- and anaerobic bacterial infections. In this study, the effect of the selected parameters such as temperature, pH, Ca+2,Na+, Mn+2, Fe+2 and Zn+ cations on the activity of nalidixic acid, ciprofloxacin, o floxacin and enrofloxacin against coliform bacteria were investigated by using broth dilution method in Muller-Hinton medium. The results obtained, revealed that, temperature 25-35°C resulted in reduced activities of quinolones and fluoroquinolones. While temperature 40°C, increased the efficiency of these agents. Acidic pH (up to 5.5), increased the activities of quinolones and decreased the activities of fluoroquinolones against bacteria. Whereas alkaline H, (up to 8.5), show opposite impacts. NaCl, up to concentrations 250 mg/ml, have no significant effects on the activities of these agents. Addition of CaCl2, FeSo4 and MnS04, up to 250 mg/ml, decreased the activities of the agents. Adding of 100 mg/mlof ZnCl2, to the medium has little effect on the activities of these agents. It seemed the activities of the therapeutic substances used, varied under various environmental parameters. In each case, one must find optimum conditions of the agents used in vivo, in order to have the most effective against infections.

Recently green house production of cucumber (Cucumis sativa L.) has been increased enormously in I.R. iran and other parts of the world. This study was conducted to investigate the effects of two exogenous plant growth regulators, lAA and GA3, on production, vegetation, and infrastructure of parthenocarp cucumber (Cucumissativa), Holland Royal Star cultivar, in greenhouse conditions. Two concentrations of 100and 500ppm of IAA and GA3, alond or in combination, was sprayed every week on the plants from when they have 4 leaves and followed for 24 weeks. Experiments carried out in a 4 complete randomized blocks, each comprising 9 parts: 8 treatments and one for control. Each part included 8 plants in 2 square meters. Vegetative and reproductive factors such height, number of leaves, male and female flowers, and number of fruits was measured every week and the data was analyzed using ANOV A. Study on infrastructure of plants was carried out using conventional methods. Results showed that the combination of 500 ppm IAA and 100 ppm GA3 led to produce significantly more vegetation and female flowers (p<0.01) in which number of fruits was 2.78 times more than control. Interestingly, significantly (p<0.011) more male flowers appeared when the combination of 100 ppm IAA and 500 ppm GA3 used. The hormone treatments have caused different infrastructural alteration in various parts of the plants such cortical and pith parenchyma’s, xylem vessels, and structural tissues. The results of this study could be applied in green houses to increase production of cucumber.

Water deficit and salinity are the two major constraints for growth and survival of plants and effects of these environmental stresses on plant growth has been investigated for more 100 years. In order to study interactive effect of salinity and aridity on growth of two species of A.littoral is and A.logopoides an experiment in a factorial design with completely randomized arrangement and four replications was conducted under lab conditions. Treatment were 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. Water deficit was induced by weight method based on 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 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 based on 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 sampling was made and different measurement recorded. The results showed that in general both water and salt stress caused a decrease in leaf area per plant, RGR, underground and aboveground biomass, plant height, root length and shoot/root length ratio. There was an interactive effect of salinity and water deficit on most of the parameters measured.