جستجوی مقالات مرتبط با کلیدواژه « spore » در نشریات گروه « زیست شناسی »

Among the mycorrhizal fungi, arbuscular mycorrhizal fungi are the most common symbiotic species with plants. Root colonization by these fungi increases plant resistance to biotic and abiotic stresses, enhances growth through increasing elements uptake, improves the water connection of plants, and protects plants against diseases.

In this study, eight plants were selected from Joupar and Mahan regions of Kerman province and were sampled from 0 to 30 cm depth of rhizosphere of each plant, which included thin soils and roots, to calculate the frequency of arbuscular mycorrhizal fungi in the soil, identify spores, and determine the percentage of root colonization. For staining the roots, Philips and Hayman’s method was used and root colonization percentage was determined. Spore density in soil samples was obtained after the extraction of spores from 10 grams of the soil sample by the wet sieve method and existing spores and also dominant spores in the soil of each plant were determined and then the data were statistically analyzed.

All the examined root samples showed a symbiotic relationship with arbuscular mycorrhizal fungi. The percentage of colonization in evergreen, oregano, chicory, safflower and castor plants was 100% and in purslane, gall and chamomile were 98%, 95%, and 88%, respectively. The average number of spores per 10 grams soil was 18, 62, 16, 34, 3, 15, 25, and 7 respectively. Based on statistical analysis, it was found that there is a direct relationship between the number of spores and the percentage of mycorrhizal colonization in most plants. Then, the available spores as well as the dominant spores in the soil of each plant were identified.

High spores per 10 grams of soil and the high percentage of mycorrhizal colonization in the study area indicated that such climates are the valuable natural repository for plant species, animals, and microorganisms.

One of the ways to reduce cholesterol is to use statins that prevent cholesterol synthesis. The statins are similar to mevalonate and act as a competitive inhibitor of HMG-CoA reductase enzyme. Lovastatin is the eminent derivate of the statins group, which is produced by many microorganisms. At commercial scale lovastatin is produced in submerged culture by Aspergillus terreus. The industrial production of this metabolite is carried out by Aspergillus turosus in liquid culture. The main aim of this research was to investigate the effect of spore age on lovastatin production at the inoculation stage; also, the impact of adding olive oil and tetracycline as inducers for lovastatin production were examined. In the present experimental research, different suspensions from varying ages of spore were prepared and added to the medium of Aspergillus terreus ATCC 20542; lovastatin concentration also was measured by High Performance Liquid Chromatography (HPLC). Findings: The utmost lovastatin was observed in inoculum with 85 days spore age and equal to 60 mg/l, which was approximately twice higher compared to when inoculated with 10 days spore age. The best concentration of spore inoculation was 0.5×107 spores/ml. Lovastatin production significantly increased when tetracycline and olive oil were used as inducers. As the inoculated spore age increases, lovastatin and biomass production is increased. The lovastatin production is increases by more than 1.5 times while adding tetracycline and olive oil compared to date syrup alone.

Plant-mycorrhiza symbiosis increases ecosystem biodiversity and stability. However it may be affected by the environmental disturbances. Effects of wildfire burning were assessed the colonization rate of VA mycorrhizal fungi with four perennial grasses Festuca ovina , Poa bulbosa , Stipa barbata and Agropyron trichophorum, in Dasharasi rangelands, Quchan, Iran. In spring 2013, 10 random samples were taken from root and soil media of each species. Results in control site, indicated highest and lowest colonization rates for A. trichophorum and P. bulbosa, being 69.11% and 43.6% respectively. Wildfire burning significantly (30%) reduced colonization of S. barbata, and total spores of symbiotic fungus with F. ovina , S. barbata and A. trichophorum , but it significantly increased (22%) spores of symbiotic fungus with P. bulbosa. In conclusion, wildlife burning at summer may reduce ecosystem stability against the environmental disturbances, via decreasing the mycorrhiza symbiosis with bunch grasses but increasing the symbiosis with ephemeral opportunistic grasses.

Resistance to anti-cancer therapy in patients with advanced solid tumors reveals the need for new treatments. Major challenges of Anti-cancer therapy is, specificity of treatment. Treatment will be ideal if cancer cells be eradicated without side effects on normal cell.
Bacteria are used in different ways to treatment of cancer, either to provide direct tumoricidal effects or to deliver tumoricidal molecules .there are two ways to use bacteria as vectors, included, tumor-specific bacterial replication and intracellular plasmid transfer. On the other hand, Bacterial toxins act by killing the cells and control of cellular processes for example cell proliferation, differentiation and apoptosis that they are associated with cancer. Spores are very resistant bacteria that survive even in oxygen-rich conditions, but, they are not able to grow. In conditions tumor the spore grow and germinate without affecting on normal cells. Bacteria and immune system: bacterial DNA vaccines apply immune system against cancer cells via cancer antigen Presentation. Here, we review the Different applications of bacterial therapy, mechanisms of action and successes at preclinical and clinical levels. Further developments in these studies will add a new dimension to cancer treatment.

Arbuscular mycorrhizal fungi (AMF) are the most important microorganisms of soil having an important role in soil fertility. In this research, the correlation between soil nutrient elements and Arbuscular mycorrhizal fungi colonization and spore numbers in the rhizosphere of Thymus kotschyamus Boiss. & Hohen. growing in the three regions (Taf, Vark and Kohkala) of Noujian watershed were studied during spring and autumn. Influence of arbuscular mycorrhizal symbiosis were also determined on vegetative characteristics and essential oil yield of T. kotschyamus.The results indicated that magnesium significant positive correlation with arbuscular mycorrhiza fungi spore density (.84) and percentage colonization (.92). Soil organic matter no significant linear correlation with arbuscular mycorrhiza fungi spore density and percentage colonization. Potassium negatively correlated with spore density and percentage colonization respectively; -0.85 and -0.90. Arbuscular mycorrhizal fungi colonization significant linear correlation with dry weight (.79). Essential oil yield of T. kotschyamus positively correlated with that of spore density and percentage colonization respectively; .93 and .91. Given the importance of mycorrhizal symbiosis and compilation this with soil elements, this information can be useful for development of medicinal plants in agricultural ecosystems.

Dipicolinic acid (pyridne 2, 6 dicarboxylic acid) is a major component of bacterial spore and is unique in that it has been found only in bacterial endospore. This study was aim to evaluate the environmental stress on DPA production in Bacillus cereus PTCC1015.  

In this experimental study the effects of environmental stresses including temperature, ethanol, NaCl and pH on the production of DPA by Bacillus cereus PTCC 1015 were evaluated by colorimetric assay (the color complex formed by interaction of ferrous iron with dipicolinic acid) and comparison with standard curves.

The results showed that the amount of DPA in B. cereus decreased upon increase in acidic condition and salt concentration in the medium. DPA formation increased at alkaline pH 8-10. DPA formation decreased in the medium containing 5-55% of ethanol. DPA formation was higher in optimum temperature at 30 ºCin comparison to the reference strains. The cell concentration decreased at 90 ºC and level of DPA detected in this stage.

In stressful condition, DPA formation significantly reduced and these properties can be used in food and dairy industries to control spore production of Bacillus cereus.