IRANIAN JOURNAL OF BIOLOGY
Year:2003 | Volume:14 | Issue:1-2|Papers Count:8

Blakeslea trispora. a filamentous fungus. Was cultured with or without accompanying strains of Micrococcus luteus. Bacillus subtilis, Streptomyces fradiae. And Saccharomyces cerevisiae which were added separately to 24 h old cultures. in order to increase beta-carotene production. It was shown that by adding M. luteus. the β-carotene production in the culture medium was increased about 2.7 times -in comparison to control. B. subtilis and S. fradiae showed no considerable effect on β -carotene production while S. cerevisiae had a negative effect. M. luteus was then added to unmated plus and minus types of B. trispora leading to a little increase in beta- carotene production compared to the control. The positive effect of adding M. luteus was only due to the existence of its life cells. Since addition of autoclaved or cell-free culture supernatant of this bacterium did not increase the beta-carotene production in B. trispora cultures.

Macrophages are one of the most important cells in the immune system that plays important role in immunoregulatory against poisoning and different infections. Lead is one of the heavy metals that it's poisoning is responsible for a variety of pathological states. In this study we have attempted to characterize the effect of various concentrations of lead nitrate on alveolar macrophages. After incubation for different period and different concentrations of lead nitrate. The survival rate. Anion super oxide production. DNA fragmentation and cytological analysis Vivre determined. The results show that after 3 and 6 hours of exposure of alveolar macrophages to low concentrations of lead nitrate (15-60uM) the survival rate is above 87% and in high concentrations of lead nitrate the survival rate is less than 80% DNA fragmentation was analyzed by diphenylamine reaction. After, and 6 hours of exposure significant increase in DNA fragmentation and anion superoxide production was observed. Cytological anal. Sis revealed that at low, concentrations of lead nitrate and short period of time. The nucleolus of the cells was condensed and fragmented. Whereas at high concentrations of lead nitrate and long period of times. It was swollen and the integrity of the membrane was lost. It is suggested that at low concentrations of lead nitrate. The cells go under apoptosis. At high concentrations causes necrosis.

In this study, the effects of sesame oil on spatial learning have been investigated. Male rats were trained for a spatial learning task using T-Maze. The rats divided into four groups and 8 rats were considered for each group. The first group, control group wad fed with an ordinary diet and other groups were fed with a diet containing sesame oil (10%) for two, three and four weeks. All rats were trained for 9 days based on standard method. Results showed an increase of spatial learning in rats fed (10%) sesame oil in their diet for four week (p<0.05), but significant was not for two and three weeks. The sesame oil consists of unsaturated fatty acids and phosphatidil cholin (lecithin) that can decrease cholesterol. It seems that it has a molecular role in spatial learning in rats. Probably, the change in activity cholinergic system is as a result of existence of lecithin component in sesame oil.

In order to study the aglal flora in this river, 17 sampling sites were determined. Sampling was performed with 45 days interval from May 2000 to Sept. 2001. Using 400x and 1000x microscopic magnification, prepared sub samples were examined taxonomically. In total of 152 taxa were identified. Bacillariophyta with 71 species belonging to 24 genera were found to be the most diverse division in this study. Navicula spp. and Nitzchia spp. were found to be the most common genera in this study. Chlorophyta (with 16 genera and 36 species) and Cyanophyta (with 17 genera and 35 species) were sub-dominant groups. Among Chlorophyta members of Chlorococcales (particulary Scenedesmus spp.) and some desmids were more frequently observed. Oscillatoria spp. (Cyanophyta) were observed in most water samples. Although Euglenophyta (with 2 genera and 5 species) Dinophyta (with 2 genera and 3 species) showed low diversity but some of their members (particularly Euglelw spp. and Peridinium spp.) were frequently observed in this river. Both Chrysophyta and Cryptophyta had one species in the water samples. In comparison with the previous studies showed that a regular survey of Diatoms flora in this river is important in the water quality control and river management.

This study was carried out in certain parts of Khorasan province to investingate some autecological aspects of Hypericum perforatum L. an important medicinal plant species. Geographical distribution of the plant in Khorasan was determined. Morphology regeneration strategy. phenology, life form as well as effects of topographical factors including altitude. aspect and slope on the plant characteristics such as its density and cover percentage was investigated. Soil parameters such as pH, EC, texture. total nitrogen and phosphorus content were analyzed. Seed germination. dry matter content of the organs were also determined. Ecological indicator value system of Borhidi along with the knowledge obtained for the species was used to develop ecological indicator values for this species. The results showed that H. perforatum is regenerated either by seed or mostly by runners in the base of the stem and grows well in non saline. calcareous and light soils with the pH ranging from 7.5 to R. Phenological investigations of the plant in the area showed that germination begins in March. flowering at June. fruit setting at the late June. seed forming at the first July and seed ripening by the mid October. Topographical factors such as aspect and slope had greater effects than altitude on distribution of the species. Ecological indicator values assigned to the species based on soil nitrogen content. soil moisture. salinity level and light of the habitat were 5-7. 3-5. 0 and 4-6. respectively.

In this research, Floristic and ecological characters of Saivan region that is situated in 45th km northwest of Tabriz were studied. This region is located between 45° 50' 40" to 45° 52' 57" E longitude and 38° 20' to 38° 21' 12" N latitude with an area of 1000 hectares. The region of vascular flora was exactly determined and 230 species belong to 179 genera and 50 families were determined. Some ecological conditions such as: soil tissue spoils pH. Soil salinity. Quality and quantity of average precipitation and average temperature in year was studied. The region vegetation was studied by floristic and physiognomic methods. By physiognomic study of the vegetation region. Different biological types were determined and the region life spectrum was designed. The floristic study of the vegetation region was carried out by Braun - Banquets method. In this way after determing minimal area. 17 releves were made inn the region. Then this releves were treated by mathematical and comparative methods. So that. Vegetation Units of the region was recognized. In mathamatical method. Jackard coefficient and in comparative method .raw. constancy. partial and ordinated partial tables have been employed. As a result. edaphic factors are most important factor: in distribution of Vegetation units.

The genus Triticum L. contains about 20 species at world wide and about 11 in Iran. There is no general agreement on the number of wild Triticum species occur in Iran (T. boeoticum Boiss T. monococcum L. and T. urartu Tum. ex Gand.) Due to lack of a precise taxonomic treatment on the genus in Iran. This study concerns the morphological and taxonomic studies on three wild diploid species. at T. boeoticum (27 accessions). T. monococcum (10 accessions) and T. urartu (2 accessions). Using 7 quantitative and 8 qualitative characters. Based on the results of this study the quantitative and qualitative morphological characters showed significant intra and inter specific variation among the taxa studied. The spike's features such as: apex of glume. number of awn in lemma and length of awn are to be the best diagnostic characters in the taxa investigated.