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The species Astragalus podolobus is one of the endemic species of winter pastures that grows in arid and semi-arid areas in the north of Gonbad-e Kavous. To investigate effective methods of breaking seed dormancy of Astr-agalus podolobus, an experiment was carried out in the framework of a completely randomized design with 15 treatm-ents and 3 replications. Treatments included controls, 98% sulfuric acid, dry chilling for 10 and 15 days, wet chilling for 10 and 15 days, and boiling water 1, 3, 5, 10 and 15 minute, respectively. Analysis of variance showed that the perc-entage and speed of germination were significant in different groups while the average time of germination in different treatments was not significant. The results of comparing mean values showed that the percentage and the speed of germination in boiling water treatments were best in comparison with other treatments with significant differences. The results of this experiment also showed that reducing the exposure time of seeds to boiling water increases the germination percentage and speed, consequently, the highest percentage and speed of germination was observed in boil-ing water 1 minute. Boiling water 1 minute treatment can increase the germination percentage up to 47% and the seed germination speed from 0.43 to 3.09 seeds per day

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Nowadays, brown macroalgae are considered to be a source of various nutritional and pharmaceutical compounds. In addition, fish roe is very susceptible to spoilage due to its high amount of protein and unsaturated fatty acids. In order to postpone the deterioration of roe-related products, salt and preservatives are utilized. Natural preservatives are recommended because of the adverse effects of chemical additives. Thus, different concentrations of pure alginate (0.1%, 0.2%, 0.3%, 0.4%, 0.5%) were chose and then the 0.2% alginate was selected on the basis of the sensory evaluation of the results. Moreover, the treatments including control (salt-alginate-free), A₁ (containing 2.5% salt) A₂ (containing 0.2% alginate), A₃ (containing 2.5% salt and 0.2% alginate) were used to investigate their preservative effects on fish roe. The quality of rainbow trout roe was assessed within 0, 15, 30, 45 days at refrigerated storage. The treatment A₃ showed significant differences in microbial, chemical and sensory results compared with other treatments (p≤0.05). According to the results, salting 2.5% and alginate 0.2% method gave good flavor and increased shelf life to the roe.
 


 

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Exopolymers (EPS) are high-molecular-weight polymers secreted by some micro-organisms and have several applications in food, pharmaceutical, packaging and agricultural industries, as well as medicine. Actinobacteria are valuable bacteria in biotechnology and many commercial drugs such as antibiotics, antioxidants and immune-suppressant agents are derived from Actinobacteria. Recently, their other capabilities such as exopolymer production have been taken into consideration. Due to the high potential of actinobacteria in producing various compounds and increased prevalence of infections by antibiotic-resistant pathogens, the aim of the present study was to evaluate the potential of isolated Actinobacteria from various locations of Iran to produce EPS with antimicrobial activity. Appropriate dilutions of the samples were, therefore, cultured in ISP2 medium after treatment. The isolates were primarily identified by morphological tests. Then, their ability to produce EPS was investigated in BHI medium with 5% sucrose. The exopolymers of the most efficient strain were analyzed by UV-visible spectroscopy and FT-IR. Finally, the most efficient isolate was molecularly identified. Of the 120 isolates, 38 were able to produce EPS, and six had significant capability of producing EPS (10-14 g/L) and showed antibiotic activity against Staphylococcus aureus, Bacillus subtilis and Aspergillus niger. The EPS of the strain So49 had high absorbance in 190-230 nm, but did not have absorbance in 260-280 nm. Therefore, it does not have any protein impurity. The EPS has hydroxyl and carboxyl functional groups, according to FT-IR analysis. 16S rRNA gene analysis showed that the most efficient isolate had 99.68% similarity to Promicromonospora xylanilytica. 


 

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Overgrazing affects plant communities, and is a significant disturbance factor in arid and semi-arid regions. The immediate changes of plant communities after overgrazing in the disturbed arid ecosystems of Iran have been poorly studied. We recorded data from 100 random samples before and after overgrazing in the Golbahar plain located in the northeastern Iran to determine the changes in the plant physiognomic, species composition, and diversity after overgrazing. We compared life-forms spectra, change in the RIVI of the recorded plant species, species composition, and species diversity before and after the grazing. Our results showed that therophytes were the dominant life-form in the area, and decreased after overgrazing. The community composition of the area remained unchanged after overgrazing. Species diversity at the level of rare and frequent species reduced after overgrazing. Our findings implied that overgrazing could not immediately affect the community structure of degraded arid areas. However, it causes changes that might reduce ecosystem services in them. It is not possible to completely exclude grazers in such areas, fencing or reducing the number of the livestock entries should be applied to restore the vegetation in the area.