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

Investigation of factors affecting endothelial cell proliferation is an essential part of angiogenesis studies. Given the importance of inhibiting angiogenesis in the treatment of cancers, and due to the side effects and high cost of anti-angiogenic drugs such as Avastin, the use of physical agents to aid in treatment and reduce the need for high doses of the drug is noteworthy. Magnetic fields are of interest due to their long-distance and non-invasive effects, and many studies have been conducted on their effects on biological phenomena, including angiogenesis, with inconsistent results. In the present study, the effect of a 2 mT alternating magnetic field with a frequency of 200 Hz and Austin on the proliferation of human umbilical vein endothelial cells (HUVEC) was investigated. Cells were treated for 48 hours under a mixture of 50 μg/ml solution of vascular endothelial growth factor (VEGEF) and Avastin at concentrations (zero (drug control), 50, 100, 200 and 400 μg/ml) as well as field treatment groups for They were exposed to magnetic fields for 3, 6, 12, 24 and 48 hours. Then, cell proliferation was assessed using Alamar Blue colorimetric test. Data were analyzed by three-way analysis of variance. According to the findings, the exposure times of 12, 24 and 48 hours showed a significant reduction in cell proliferation compared to the control group, but this difference was not significant in the 3 and 6 hour treatments. Also, the degree of interaction of these factors with each other on HUVEC proliferation was investigated.

Salvia sahendica Boiss. & Buhse.  with antimicrobial, antioxidant and anticonvulsant properties is an endemic species of the lamiaceae family that grows in the Sahand highlands in East Azerbaijan province. The aim of the present study was to investigate the quantity and quality of essential oils and effect of different treatments on the percentage and germination rate of this species due to the low germination percentage of its seeds. The aerial parts of the plant were collected at flowering stage in the summer of 2012 from Kasai habitat in Tabriz Then, its essential oil was obtained by clevenger method and analized by GC/MS. Seed test was conducted based on a completely randomized design (CRD) with 4 replications. Treatments included gibberllin at three levels of concentration (100, 150 and 200 ppm for 24 h), three levels of wash time (12, 24 and 72 h), chilling at three levels of duration (for 24, 48 and 72 h) and magnetic treatment (50 and 130 mT for 5, 10, 20, 25 and 30 min) and control. Based on the results, the essential oil yield of this species was 0.8% by weight and the presence of 23 compounds including trans-meta-mentha-2,8-diene, spathulenol, α-Pinene, 1,8-cineol and β-pinene in the essential oil components of this plant was proved. Seed test result showed that seeds treated with 100 ppm gibberellin had the highest germination rate (47 %) and seeds treated with 130 mT for 20 min had the highest germination rate (5.83) compared to control (16) and (1/99) respectively. The results indicate that the seeds of this species have physiological dormancy and different treatments can significantly increase.

Amniotic fluid (AF) is essential for fetal development and maturation during pregnancy. The levels of proteins in AF have been determined in many studies to screen for potential biomarkers of pregnancy-associated abnormalities. Alpha-fetoprotein (AFP) is a major AF and plasma protein produced by the yolk sac and the liver during the fetal period. APF serum concentrations are commonly used for screening of many syndromes. Electromagnetic fields (EMFs) were reported to change gene expression in the embryo and in adults. The aim of this research was to assess the effects of 50hertz/1millitesla EMFs on AFP expression in the AF in the mouse embryo. AF samples were obtained from pregnant mice in gestational days 16 and 18. AFP relative expression was studied by western blotting. The results of this study showed that AFP relative expression increases in the EMF-treated AF as compared with either SHAM or control groups. It is concluded that EMF increases the AFP relative expression in the AF. It is also suggested that EMF may change the AFP expression in the AF by altering the expression of genes, including AFP, and/or by affecting the permeability of blood barriers.

Magentotactic bacteria are the types of bacteria capable of orientation in an external magnetic field because of the ability to produce structures called magnetosomes. Magnetosomes, nanometer-scale structures, are present in most of the magnetotactice bacteria. They are intracellular organelles composed of magnetic iron mineral crystals individually surrounded by a phospholipid layer. Because of the unique features of magnetosomes, magentotactic bacteria have become the fascinating subject of research in many research and applied fields of study, including robotics, medicine, biology, environment and geology. In this review, we have tried to introduce magentotactic bacteria, the formation of magnetosomes and their structures, in order to highlight the importance of these bacteria. Finally, some applications of these bacteria in different areas of research, e.g. targeted drug delivery, cancer treatment and removal of heavy metals from water, were described in order that a better understanding of their applications could be obtained.

Water, the vital element for survival and its quality and resources are substantial for every country. This study was based to investigate the effect of the magnetic field and Nano filtration on some growing characteristics of tomato such as days to germination, germination percentage, germination rate, height, root length, biomass, dry matter, chlorophyll a, b, total, carotenoids, and the absorption rate of NPK, Fe by the leaves, based on a factorial experiment in a randomized complete block design with three replicates was conducted. In this respect, two levels of magnetic field, four levels of Nano filtration and three levels of water circulation were included. Overall, the results indicated that the magnetic field had a positive influence, while the impacts of Nano filter were considerably less. Likewise, it is vital to note that the effect of the magnetic field was significantly higher in interrelationship samples. As a consequence, on the basis of the results, a magnetic water treating device has been manufactured. Overall, with the aim of the device, the required amount of chemical fertilizers would plunge by which their detrimental impacts upon environment could be reduced markedly.

In order to study the effects of magnetopriming on the physiological and phytochemical characteristics of Hyssopus officinalis plants, this research was conducted as a factorial experiment in a completely randomized design. Results showed that magnetopriming (particularly at 200mT/5 min) increased the level of shoot dry weight (82.6 percent), root dry weight (86.5 percent), total chlorophyll (32.8 percent), carotenoids concentration (32.4 percent) and polyphenols content (2 folds) in 60-day-old Hyssopus officinalis. Also, electrolyte leakage and lipid peroxidation decreased by 27.6 and 45 percent, respectively. In addition, reducing power, DPPH and superoxide anion scavenging activities significantly augmented. However, higher activities of superoxide dismutase (76 percent), catalase (4.2 folds), ascorbate peroxidase (2.4 folds) and guaiacol peroxidase (48 percent) were found at 90 mT. Results suggested that the application of magnetopriming promoted growth in H. officinalis through augmentation of cellular membrane integrity as well as biomass and photosynthetic pigments content. Furthermore, it was found to enhance the antioxidative system. Magnetopriming might apparently improve the medicinal properties via increasing the level of polyphenols and antioxidant capacity in H. officinalis.

In recent years a lot of researches have been carried out about sensitivity of the living organisms to magnetic fields and nanoparticles. Therefore, to evaluate the effect of the magnetic field and silver nanoparticles on photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids), proline, glycine betaine, soluble sugars and proteins, nitrate and nitrate reductase activity and protein electrophoresis pattern on Calendula officinalis L., in 2015 experiments were performed in the Department of Biology, University of Urmia. Seedlings were grown for 30 days in four treatments including: control, magnetic field with B = 3 mT for an hour per day, silver nanoparticles (50 ppm), and magnetic field (B = 3mT) plus silver nanoparticles (50 ppm). The results showed that plants treated with magnetic field, silver nanoparticles and magnetic field silver nanoparticles photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoids) content, compatible solutions content such as proteins and soluble sugar, proline andglycine betaine and nitrate content and nitrate reductase activity were significantly (P

Catharanthus roseus L., commonly known as the periwinkle, is one of the most important medicinal plants that included worthwhile alkaloids. The effect of the intensity and duration of magnetic field, medium strength and growth regulators were investigated on percentage of seeds germination. Sterilized seeds were exposed to different intensities of magnetic field (1, 2, 4mT) daily for 15 minutes during a week or a month. Treated seeds were cultured in MS or 1/2 MS media supplemented with different hormone combinations. Results indicated that application of MF for one month period caused the decrease in seed germination. To Investigate the hormone combination effect, the MF treated seeds were cultured in 1/2 MS media supplemented with 2,4-D and kinetine. In the presence of 2,4-D, the percentage of germination, production and growth of callus were increased. In the culture medium containing 2iP or Kinetin, seedling growth was performed without callus formation. Kinetine increased the number of shoots in a seedling without induction of callus production.

Electromagnetic field is a stress factor which can interfere with the functions of body organs. This study aims to evaluate the protective impact of the aqua extract of Persian Gulf sea cucumber on damages induced by low frequency electromagnetic field in male gonads of Balb/C mice. Mice were divided into control, sham-exposed and 5 experimental groups. The experimental groups were then exposed to electromagnetic field (for 10 days and 4 hours per day). Experimental groups 2-5 also received extract of sea cucumber (6h before electromagnetic field). The samples were fixed for histological studies and stained by H & E method. The measurement of the diameter and number of seminiferous tubules, testis diameter, testis and epididymis weight, tunica albuginea thickness, the number of spermatogenic cells including spermatogonia, spermatocytes, spermatids, Sertoli cells and Leydig cells was then executed. The results showed that the impact of electromagnetic field exposure was not significant on epididymis weight, seminiferous tubules diameter and tunica albuginea thickness, while its impact on the reduction of the testis diameter and weight, the number of seminiferous tubules and spermatogenic cells was significant in experimental group 1. In addition, the experimental groups pre-treated with sea cucumber extract indicated significant increment, as compared with experimental group 1.The results proved the destructive effect of electromagnetic field on testis tissue parameters, while sea cucumber extract prevents damages induced by electromagnetic field on male sexual glands of mice.

Effects of ozone depletion and increase of UV radiation have been studied by many researchers. The aim of this study was to investigate the effects of UV-B radiation on Melissa officinalis L. as well as the impact of salicylic acid and magnetic fields in the reduction of harmful effects of radiation on plants. The Melissa officinalis L. plants were treated with 28 ± 2 Cº for approximately 60 days. The light intensity was 150 µ E mˉ² Sˉ¹ and the light/dark regime was 16/8 h. UV-B treatment was applied after the six-leaf stage for a period of 15 days and 20 min every day. Salicylic acid (1mM) was daily sprayed on the plants after the six-leaf stage for one week. Magnetic field treatment was applied for an hour with intensities of 0, 40 and 85 mT. The results indicated that the UV-B radiation led to reduction of root and shoot dry and fresh weights, and root and shoot elongation. The radiations also reduced the content of photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoid), sugar and soluble proteins. The phenylalanine ammonia-lyase activity and UV-absorbing content compounds increased under the effect of UV-B radiation. The results showed that treatment with salicylic acid and magnetic fields reduced damages to the plant due to UV-B radiation.

Magnetic field is an environmental factor for living organisms which affects biological processes in different ways. Living cells contain electrical charges which are produced by free ions or radicals. Magnetic fields can influence cells via interaction with ions and especially ferromagnetic materials, like iron. In this study, parsley or Petroselinum crispum cells were treated by static magnetic field (30 mT, for 4 hours) and the total content of iron, ferritin and the activity of ascorbate peroxidase, superoxide dismutase and catalase were assayed. Results showed a significant decrease in the total iron content and it was followed by a decrease in ferritin content. Ascorbate peroxidase activity was reduced. It could be resulted by decrease of iron as a structural element. However, superoxide dismutase and catalase activity increased in response to magnetic field compared to the control cells. It seemed that catalase activities increased scavenge H2O2 produced by increasing superoxide dismutase activity.

The objective of the present study was to investigate the effect of static magnetic field (0، 25 and 50 mT) and the exposure time (0، 30، 60 and 120 minutes) in Nigella sativa L. seeds germination. The results showed that magnetic field application enhanced seed performance under laboratory germination tests. In these magnetic fields، treatment of N. sativa L. seeds increased significantly the germination، speed of germination، root length، seedling length، seedling fresh and dry weight and vigor index I and II compared to control. Among the various combinations of field strength and duration، 25 mT for 60 minute showed the best results. In germinating seeds، enzyme activities of α-amylase، dehydrogenase and protease were significantly higher in treated seeds to compared to the controls. The higher enzyme activity in magnetic-field-treated N. sativa seeds could trigger the fast germination and early vigor of seedlings.