IRANIAN JOURNAL OF BIOLOGY
Year:2004 | Volume:17 | Issue:1|Papers Count:9

Zygomycetous moulds were isolated and purified from different sources such. as soil, . atmosphere, compost and waste-water from cheese-producing industries. Qualitative Casein hydrolysis test was performed on skimed milk medium. Proteinase asparatic enzyme was prepared on. SSF medium in the presence of wheat bran and tap-water. One of each of the solid medium was inoculated with spore suspension of each mould and then incubated at 27 C for 72 ill under dark condition. After incubation period, 0.1 M citrate buffer (pH = 3.5) was added to the flasks containing mould-spore inoculated wheat bran media and then media were filtered  through the Watman filter paper No.1. Proteolytic enzyme activity was determined using modified Anson method with Uml-1 min-1. Milk-clotting activity was assessed for each enzyme based on Soxhlet scale and the ratio of clotting to proteclytic activity was detennined for the enzymes. The highest milk-clotting ratio (6859) was obtaincd for a Mucoraceous species isolated from soil. The enzyme of this mould was saturated in 1% casein substrate in pH 4.5. The optimum pH was determined to be 4.5. However, this enzyme was active at 60,C but its activity was suppressed at 65C.

This research was conducted to evaluate effect of calcium nitrate [Ca (N03) 2] on changes of electrophoretic pattern of soluble proteins in rice seedlings under salt stress conditions. The experiment was designed as completely randomized factorial design and three replications. The treatments were consisted of different concentrations of calcium nitrate (0, 1. 5, or 10 mM), EGT A (calcium chelator, with 5 mM concentration), four levels of salinity (0, 50, 100, 150 mM of NaCl), and two varieties of rice (Tarum and Gerdeh). One week after application of treatments, the electrophoretic pattern of proteins and soluble proteins in rice seedlings, germination percentage, and length of root and shoot were determined. The results indicated the electrophoretic pattern of proteins Was changed by salinity, but calcium nitrate and EGTA had different effects on the electrophoretic pattern at various salt concentrations. By increasing salt concentration up to 100 mM, the amount of soluble proteins in both varieties decreased. While at 150 mM concentration of salt, the total soluble proteins in both varieties increased. The seedlings of Gerdeh had significantly (1 %) more soluble proteins than the seedlings of Tarum. However in both varieties, the total soluble proteins was increased by calcium nitrate and decreased by EGT A treatment. In both varieties germination percentage, length of shoot and root were significantly reduced by increasing salt concentration. Clacium nitrate treatment improved percentage of germination, and length of shoot and root. While EGT A aggravated the effect of salinity and caused a reduction in germination percentage, and length of shoot and root.

A biochemical marker (Paterns of seed protein electrophoresis) was applied in order of grape classification in province western Azarbayjan because of the economic and agronomic importance of grape in this region. Forty-eight cultivars were analyzed for genetic diversity and polymorphism in 4 gene loci. In this study one of the loci was mono morph but variation was observed for the three gene loci. Seven teen bands were resolved by SDS-P AGE method under reducing conditions. The profile of grape seed storage proteins were simple with low molecular weight peptids (12 KDa - 60 KDa). For each variety a binary chart was used based on the present(1) or absente (0) of distinctive bands. Similar sample matrices were computed from these data and then dendrogram were then created via UPGMA (Unweight Pair Group Method Using Arithmetic Means) method. Cluster analysis based on qualitative evaluation of patterns grouped the cultivars in 8 clusters.

Effect of salinity (sodium chloride) on growth and biological nitrogen fixation (BNF) was investigated in roots of alfalfa (Bami and American cultivars) inoculated by six different strains of Sinorhizobium bacteria. These strains contain a wild type named S me/iloti Wild type (S392), two mutated strains S me/iloti nifK (S259) and S.me/iloti nifH(S237), which were without plasmid and three strains W T(pSRK9), nifK (pSRK9) and nifH (pSRK9), with plasmid. This experiment designed using a factorial model in randomized complete blocks with four replicates. Salinity treatments were 0, 50, 100 mM sodium chloride. In this experiment, vermiculite culture with combination of FP nutrient solution (without nitrogen) was used. The pots were arranged randomly in a growth chamber with a 16-8 h light-dark cycle, 23-20˚ C day-night temperature, relative humidity 44% and 15 Klux light density. Seedlings were harvested after 50 days and active nodule number, shoot length, dry weight of whole plant, sugar, content of root, total protein of root and shoot and K+ /Na + ratio of root and shoot were measured. Data analysed with SPSS software version 9. Results showed that dry weight production in salinity treatments of 0, 50 mM were the same. Mean comparison for active nodule number, dry weight of whole plant and sugar content of root about Bami and American cultivars of alfalfa showed that both cultivars of alfalfa inoculated with nifK (pSRK9) strain had better than that of others, because they produced higher active nodule number, dry weight and sugar content of root in salinity treatments of 50, 100 mM sodium chloride. In experiment conditions, American cultivar that inoculated with nifK (pSRK9) strain showed high total protein of root and shoot in salinity treatment of 100 mM sodium chloride. Measurement of K+ /Na +ratio of root and shoot showed that American cultivar inoculated with nifK (pSRK9) and W. T(pSRK9) strains and Bami cultivar inoculated with nifK (pSRK9) strain produced higher K+ /Na + ratio with increasing salinity. It seems that symbiosis between Bami and American cultivars of alfalfa with nifK (pSRK9) and W T (pSRK9) strains improved nodulation, growth and biological nitrogen fixation under salt stress. Results showed that inoculation of alfalfa plants with high salinity tolerant of Sinorhizobium meliloti bacteria which were transfered with the plasmid contain the genes that are able to fix nitrogen can improve plant production under salinity.

The pollen morphology of 9 species of the genus Ephedra L. in Iran, based on scanning electron microscopy is described and compared for the first time. These species are as follows:E. strobilacea Bge., E. foliata Boiss., E. sarcocarpa Aitch. & Hems, E. laristanica Assadi, E. intermedia schrenk & C.A. Mey., E. major Host. E. pachyclada Boiss., E. procera Fish. & C.M. Mey., E. brevifoliata Ghahreman.Differences in ornamentation of pollen surface such as ridges, furrows and hyaline lines is observed. between the species, especially with E. strobilacea.Palynological observation and other conclutions from morphological and to some extend anatomical data, show affinity of E. major and E. procera also E. foilata and E. brevifoliata and separated the E. strobilacea from other species examined.This study confimed Assadi's work (1998) who introduced E. major as synonym of E. procera and E. foliata as synonym of E brevifoliata.The scanning electron microscopy of pollen of E. brevifoliata, E. laristanica, E. strobilacea. and E. sarcocarpa are reported for the first time in the world.

Following investigation was carried out to identify some of Ascomycetes collected from Mazandaran forest. During different seasons of the year, the specimens were collected from Vaz forest which is located in Chamestan, and were studied in the laboratory. After staining the samples, microscopic characters of them such as the form and size of the ascus, ascospore and paraphysis were drawn and determined.Afterwards, the specimens were identified, being referred to the available references. The results of the identification of the collected fungi ended to the report of four new species for Iran for the first time. These species which belong to the order of Helotiales and family of Helotiaceae are as follows:Neobulgaria pura (Fr.) Petrak Ascocoryne cylichnium (Tul.) Korf Bisporella citrina (Batsh ex. Fr) Korf and Carpenter Chlorociboria aeruginascens (Nyl.) Karst.

Arbuscular mycorrhizal fungi (AMF), form symbioses with root of more than 80% plant species and leading to alterations in plant biomass, chemical composition, and I or tolerance to disease or drought. Today management of plant-microbe symbioses, such as AMF, is notified for restoration of desertified ecosystems.Here we have studied occurrence of arbuscular mycorrhizal fungi symbioses with A.sieberi in Kharturan-Semnan province, in relation to some physical and chemical properties of soil. Kharturan with 130.5 mm/year mean fall and 17.7˚C mean day temperature, have sever semiarried climate in most places. We chosen 4 sampling stations from low area around Khalshoor river to Tirkooh altitudes after observation of the zone.The plant cover of each station studied with calculation of importance value (IV) of plant species. Soil sampling done in each station and some soil elements, pH, EC and soil tissue determined. Mycoryhizal spore number in rhizosphere of A.sieberi counted from each station in spring and autumn.Results indicated that silt, Na, K and V quantities of soil had negative relations and sand, S, Mg, number of plant species and altitude had relationship with spore number in spring. In autumn Sand and Ni quantities of soil had relationship with spore number of soil.

Mucopolysaccharidosis I (MPS I) is a lysosomal storage disease that caused by deficiency of α-L-iduronidase (IDUA) enzyme. This enzyme involved in the degradation of glycosaminoglyans or mucopolysaccharides, dermatan sulphate and heparan sulphate. From clinical point of view the disease subdivided in to three categories with the most severe form known as Hurler syndrome and the mild one called Scheie syndrome. A fine correlation of genotype phenotype has been observed in this disease. Progressive mental retardation, hepatosplenomegaly, skeletal abnormalities are the common symptoms of severe form of the disease. Inheritance of the disease follows the autosomal recessive pattern. The present study performed on a family with a suspected child for MPSI. Initially by using enzyme activity assay, the Hurler syndrome was verified and then through PCR amplification of all 14 exons of the gene, SSCP and sequencing the mutation underlying the disease phenotype was detected. The mutation turned to be L132R, which has not been reported so far.

Aspergillus species are known as a usefull source of b-Glucosidases and A. niger is by far the most efficient producer of ß -Glucosidases among the microorganisms investigated.In this research ß-Glucosidases activity in 13 isolates of Aspergillus were studied by Rapid screening. Different diameter of the clearing zone surronding the clonies on the plate cellulolytic activity in these isolates. Isolate R4 and isolates 5010 and M2 showed the largest (41 mm) and lowest (15mm) cellulolytic activity, respectively.The ß -Glucosidase activity was measured in the optimum conditions for production of ß - Glucosidase enzymes in Aspergillus. In order to obtain the optimum condition: an isolate of Aspergillus was grown in Mandels media with CMC, Avicel and filter paper as carbon source at pH 5,6,7,8 and 9. Lactose and cellubiose were added to media as inducer agents. Media were incubated at 3˚DC with shaking for 10 days. samples were collected in 48h intervals, and enzyme activity was measured. Results showed that the optimum conditions for hyperproduction of ß -Glucosidase were pH=8, CMC as carbon source, lactose as inducer on second day. After screening the ß -Glucosidase activity of all 13 isolates in the optimized conditions, it was shown that R2, R3, R4, M3b, M2 and 5010 had the high level of enzyme activity and 5011, M3a and 5154 isolates had low level of ß -Glucosidase. For characterization and study of ß -Glucosidase gene, CT AB method used for genomic DNA extraction. The expected PCR product with 2806bp was amplified with two specific primers. The amplified fragment was confirmed by restriction pattern.