IRANIAN JOURNAL OF BIOLOGY
Year:2001 | Volume:10 | Issue:1-2|Papers Count:7

The proteinase aspartic enzyme is produced by many species of fungi among which Zygomycetes are of special importance. Many species of fungi belonging to the genus Mucor were isolated, purified and identified from different sources: dairy industries, different soils, different cheeses contaminated with fungi, composts and plants contaminated with fungi have been transferred to a soil medium containing %(w/w) of wheat bran for storing these molds, and for spore production they were also added to a PDA medium as an inoculum. Enzyme production was achieved in the culture medium containing wheat bran and water following solid base fermentation and enzyme solutions were obtained through the addition of citrate buffer to the culture medium followed by filtration. Enzyme activity and its coagulation ability were calculated for each case and the ratios of coagulating ability to proteolysis were determined. The highest ratio belonged to a species of Mucor which was isolated from soil. In the continuation of the experiment, for increasing the level of enzyme production, and its coagulation ability, the effects of different treatments on the above mentioned fungus were studied. The highest ratio of coagulating ability to proteolysis was obtained through the inoculation of 700000 spores to each gram of wheat bran culture medium. Ammonium chloride and yeast extract can stimulate enzyme production with optimum amounts of 1% and 1.5% respectively. Since the concerning mould was isolated from the soil, the optimum incubation temperature for the production of the enzyme has been determined as 27ºC. Enzyme production reached its maximum after 72 hours of incubation and the best pH for the production of the enzyme was determined to be 6.5. During enzyme amount the activity of the enzyme was increased when pH 6 enzyme solution. The addition of 8.9 ml of whey with a pH of 6.5 and sugar beet molasses with a pH of 6.5 and brix of 26 to the culture medium increased the enzyme production 2.93% and 5.1% respectively.      

Cortisol, in addition to its metabolic effects, influences the immunity mechanisms. Macrophages play a critical role in the production of O2, H2O2, cytokines, changes in lysosomal enzymes and also phagocytosis. The aim of the present study is to investigate the cortisol effects on the phagocytic activity of macrophages in rainbow trout in vitro. For this purpose the macrophages from pronepheros were removed into a Leibovitz medium. Then suspension were flooded onto microscope slides and allowed the phagocytic cells to adhere for 90 min. by 21˚C. After washing the slides by phosphate buffer solution (pH 7.8), the attached macrophages were flooded with yeast cells suspension. Phagocytosis was allowed to proceed for 90 min. After staining the average of engulfed yeast cells by a macrophage was determined, inspecting 200 macrophaged. The present results showed that the incubation of macrophages with cortisol depressed the phagocytosis after 3h and incubation for a period less than 3h had no significant effect. This study showed, that cortisol acts directly on macrophages and its effect id slow and time dependent

Retinoic acid is an active metabolite of retinoid involved in many metabolic functions of the cells. In this study the effect of all –trans retinoic acid on alveolar macrophage viability, DNA fragmentation and superoxide anion production was investigated. The results show that the effects of retinoic acid are dose dependent. At low concentrations, it increases the viability of macrophages and at high concentrations it reduces viability. The maximum increase is seen at 10-7 M retinoic acid. Analysis of extracted DNA from the treated and controls demonstrates that retinoic acid prevents DNA fragmentation at low concentrations. However, at high values DNA fragmentation increases. Increase in superoxide anion production is also seen after short periods in cell culture. These results together with the determination of protein content of the treated and the control group and the cytological examination of the cells reveal that retinoic acid directs macrophages through apoptosis in a dose dependent manner.

Yew (Taxus baccata L.) is one of rare endemic trees in world and Iran. Industrial and medical importance of yew was known. For investigation of environmental factors on peroxidases activity of yew, Gorgan and Arasbaran forests were selected. Gorgan and Arasbaran forests are located in the north eastern and northwestern of Iran, respectively. Those have many environmental differences, for example, humidity percent in Gorgan forest is higher than Arasbaran and annual temperature average in Arasbaran forest is lower than Gorgan forest. Therefore, in middle of summer (in a constant time) from stems, leaves and fruits of male and female yew trees in both forests were sampled. Then quantitative and qualitative activities of peroxidases in yew trees of Gorgan forests were higher than Arasbaran forests. However, all samples have not any light isoenzymatic bands, the number and activities of heavy isoenzymatic bands in yew trees of Gorgan forest were higher than that in Arasbaran forest. The number of middle isoenzymatic bands in both forests was equal but their activities in Arasbaran forest were higher in Gorgan forests.  

Pine is one of non-endemic trees in Iran. Pine is used considerably for  forest plantation. For investigation of adaptation potential of pine (Pinus eldarica) against environmental factors and due to important role of peroxidases and amylase in environmental stresses, enzymatic responses of pines in forest plantation of Chitgar (Tehran) as an arid zone were studied. In some parts of Chitgar that environmental factors (for example, edaphic and climatic elements, tree) but healthy situation of some trees was suitable (tolerant trees). Therefore, after sampling from stems and leaves of both types of trees, quantitative and qualitative activities of peroxidases and amylas were analyzed by spectrophotometric and electrophoresis methods (PAGE). Results indicated that peroxidases and amylase activities of tolerant trees were lower than sensitive trees. Moreover, isoenzymatic patterns of tolerant trees in comparison with sensitive trees were constant. These results indicated that, due to mismanagement in selection of seeds, and seedlings genetical differences in Chitgar pines are high

In this study somatic coliphages were enumerated by double agar layer method, using Escherichia coli (ATCC 13706) as the host strain. Two standard methods for determination of fecal coliforms (most probable number) and membrane filtration, and numerated spores of Clostridium perfringes (by membrane filter method) were also made to compare the fluctuations. Thirty samples of surface and ground waters were collected from Tehran city. Regeneration coefficient (r) values obtained from correlation analysis between the concentration of the coliphages, and the others (fecal coliforms by MNP, fecal coliphorms by membrane filter and spores of Clostridium perfringes). The r-value of colliphages and coliforms by MNP method was the lowest correlation (r=0.19) and that was not significant. This value for coliphages and coliforms by membrane filter method was r = 0.43 and that was a little significant. The highest correlation coefficient was obtained with coliphages and spores of Clostridium perfringes, r=0.62, and it was significant. Therefore, colliphages would be considered as an optimal indicator of pollution of natural waters by the spores of Clostridium perfringes, but not for colliform.