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Exposure to 2100 MHz Electromagnetic field radiations induces reactive oxygen species generation in Allium cepa roots
Abstract
During the last few decades there has been an enormous increase in the usage of cell phones as these are one of the most convenient gadgets and provide excellent mode of communication without evoking any hindrance to movement. However, these are significantly adding to the electromagnetic field radiations (EMF-r) in the environment and thus, are required to be analysed for their impacts on living beings. The present study investigated the role of cell phone EMF-r in inciting oxidative damage in onion (Allium cepa) roots at a frequency of 2100MHz. Onion roots were exposed to continuous wave homogenous EMF-r for 1, 2 and 4h for single day and generation of reactive oxygen species (ROS) in terms of malondialdehyde (MDA), hydrogen peroxide (H2O2) and superoxide anion (O2⁻) content and changes in the activities of antioxidant enzymes- superoxide dismutases (SOD) and catalases (CAT) were measured. The results showed that EMF-r exposure enhanced the content of MDA, H2O2 and O2⁻. Also, there was an upregulation in the activity of antioxidant enzymes− SOD and CAT− in onion roots. The study concluded that 2100MHz cell phone EMF-r incite oxidative damage in onion roots by altering the oxidative metabolism.
... Besides, mobile device radiation enhances the emissions of essential oil contents in plant seeds, while wireless routers inhibit this effect (Soran et al., 2014). Inoculating soil with Annelida (ringed worms) enhanced plant growth, antioxidant defense activities, and nutrient acquisition, increasing leaf and flower numbers, cell area, and chlorophyll content (Kaur et al. 2017). MWR affected vermicast potency for plant growth and antioxidant activities in Chinese cabbage seedlings (Abbey et al., 2017). ...
... Antioxidant enzyme activities are also enhanced by electromagnetic radiation exposure; higher electrical field strengths (23, 41, 120 V m -1 ). For example, exposure of Allium cepa roots to 2100 MHz of electromagnetic radiation enhanced malondialdehyde content and ROS production and altered antioxidant enzyme activities (Chandel et al., 2017). ...
The prevalence of electromagnetic fields (EMFs) caused by electromagnetic radiation is increasing in our daily lives, potentially bringing both adverse and beneficial effects. EMFs have garnered significant research attention in various disciplines, including agricultural science. However, our understanding of the impact of EMFs on the ecophysiological performance of plants under suboptimal conditions is limited. Despite this, there are indications that EMFs can improve crop productivity by enhancing seed germination, plant nutrition, precision farming, water use efficiency, root hydraulic conductance, plant water uptake, anti-oxidative defense , pest prevention, stress signaling, and hormonal pathways. This review highlights the practical application of EMFs for increasing plant biomass production by elucidating the underlying mechanisms involved in seed germination, plant growth, water relations, ion flux, photosynthesis, and antioxidant defense. We also highlight the prospects for using EMFs in sustainable agriculture and their potential to alleviate the conventional agricultural pressures related to food security issues.
... This suggests that plants can respond to EMF-r stimulus over a wide range of exposure Mironova and Romanovskii (2001) 53.6 GHz Increased germination Maslobrod et al. (2010) 105 GHz Induction of meristems Tafforeau et al. (2004) conditions and biological processes. One of the most frequently reported responses is an activation of ROS (reactive oxygen species) production and scavenging metabolism (Singh et al. 2012;Chandel et al. 2017) and calcium metabolism (Beaubois et al. 2007;Roux et al. 2008). This initial response could lead to two major kinds of plant responses (Fig. 1), one being rapid, associated with cellular alterations, such as DNA aberrations (Kumar et al. 2020) or malondialdehyde (MDA) production (Zareh and Mohsenzadeh 2015), and a second one that involves molecular and biochemical changes evoking delayed meristem formation (Tafforeau et al. 2004) or growth modifications (Grémiaux et al. 2016;Mildažien_ e et al. 2019), although these two types of responses are not mutually exclusive. ...
... The activation of catalase suggests that the production of H 2 O 2 was important, since this enzyme bears a low affinity toward H 2 O 2 , within the mM range, while the ascorbate peroxidase has a comparatively much higher affinity with H 2 O 2 , within the lM range (Gill and Tuteja 2010) and might, therefore, act to finely tune H 2 O 2 level. Irradiating the root tips of Allium cepa to EMF-r (2100 MHz for 2 and 4 h) for a single day induced an elevated level of superoxide ions and H 2 O 2 (Chandel et al. 2017). It is worth noting that increased ROS production was also observed after low frequency EMF-r (Abyaneh 2018) or even SMF exposure (Shine et al. 2012), suggesting that enhanced ROS production is also a universal reaction to SMF/ EMF exposures, as previously noted for Ca 2? , reinforcing the potential tight relationship between ROS and Ca 2? in the signaling events following EMF-r exposure. ...
The technological advancement and increased usage of wireless and other communication devices have greatly enhanced the level of radiofrequency electromagnetic field radiation (EMF-r) in the environment. It has resulted in unprecedented increased exposure of living organisms to these radiations. Most of the studies in past have, however, focused on animal systems and comparatively less attention has been paid to plants with studies reporting various, sometimes contradictory effects. This review is an attempt to provide a critical appraisal of the available reports regarding the impacts of these radiations on plant development and the underlying physiological, biochemical, and molecular mechanisms involved. Here, we propose that the main entry point for the biological effects of EMF-r corresponds to an increase in ROS metabolism and cytosolic calcium that leads to various cellular responses including changes in gene expression and/or enzymatic activities, which could ultimately result in immediate cellular alterations or delayed plant growth. This may constitute a new perspective in the interpretation of plant responses to EMF-r exposure. Understanding the impacts of EMF-r and the inherent abilities of plants to cope up with such changes should lead to EMF-r being considered as full-fledged environmental signals that are perceived by the plants and integrated into their development patterns.
... Long-term exposure of EMRs has shown to increase levels of toxic oxygen free radicals in both plants and animals during some studies [7][8][9][10]. These free radicals can either obtain electrons from available donors or donate an electron to a suitable acceptor, leading to modifications that generate secondary free radicals [11][12][13]. ...
The proliferation of wireless communication devices has increased the exposure of living organisms to electromagnetic field radiations (EMF-rs), posing potential risks to various biological systems. The present study was planned to explore the genotoxic effects and oxidative stress responses of 1800 MHz electromagnetic radiations in Trigonella foenum-graecum L. plant test system. The study also pertained to assess the changes in functional groups using Fourier transform infrared spectroscopy (FTIR).
Twenty seeds of Trigonella foenum-graecum L. were placed in Petri plates lined with autoclaved Whatman No. 1 filter paper. The seeds were evenly distributed and maintained at temperature 25 ± 2 °C and relative humidity 55–60%. The seeds were placed in Petri plates along with the exposure apparatus (antenna) and then enclosed within a chamber consisting of two layers of aluminium sheets. The treatment was administered every day for seven days on various parameters.
The investigation showed that increasing the duration of EMR exposure significantly decreased protein content and increased MDA content in seedlings. However, exposure to EMRs for 4 and 8 h per day led to increased activities of different antioxidant enzymes, including guaiacol peroxidase (POD), glutathione-S-transferase (GST), ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR) and superoxide dismutase (SOD). The study also calculated the specific absorption rate using the biological heat transfer equation, which revealed harmful effects of the radiations on the test system by interfering with biochemical processes, leading to genotoxic and oxidative stress.
The findings suggest that electromagnetic radiations induced oxidative stress in T. foenum-graecum L. and increased activity of antioxidant enzymes as a protective mechanism against cellular damage. The study highlights the potential risks associated with EMF radiations on plant systems and underscores the importance of further research in this field.
... The use of a transverse electromagnetic wave mode (TEM) cell to expose Vicia faba to EMRs at 915 MHz for 72 h has shown genotoxic effects (Gustavino et al. 2016). Radiofrequency radiations at 2100 MHz were shown to have cytotoxic and genotoxic effects on A.cepa root meristems, and the biological effects were time-dependent, with the largest alterations happening after 4 h of exposure (Chandel et al. 2017). Similarly, exposure to mobile phone radiations at 2350 MHz induced cytotoxic and genotoxic effects on A.cepa root meristematic cell. ...
Unprecedented growth in the communication sector and expanded usage of the number of wireless devices in the past few decades have resulted in a tremendous increase in emissions of non-ionizing electromagnetic radiations (EMRs) in the environment. The widespread EMRs have induced many significant changes in biological systems leading to oxidative stress as well as DNA damage. Considering this, the present study was planned to study the effects of EMRs at 900 MHz frequency with the power density of 10.0 dBm (0.01 W) at variable exposure periods (0.5 h, 1 h, 2 h, 4 h, and 8 h per day for 7 days) on percentage germination, morphological characteristics, protein content, lipid peroxidation in terms of malondialdehyde content (MDA), and antioxidant defense system of Trigonella foenum-graecum test system. The genotoxicity was also evaluated using similar conditions. It was observed that EMRs significantly decreased the germination percentage at an exposure time of 4 h and 8 h. Fresh weight and dry weight of root and shoot did not show significant variations, while the root and shoot length have shown significant variations for 4 h and 8 h exposure period. Further, EMRs enhanced MDA indicating lipid peroxidation. In response to exposure of EMRs, there was a significant up-regulation in the activities of enzymes such as ascorbate peroxidase (APX), superoxide dismutase (SOD), glutathione-S-transferase (GST), guaiacol peroxidase (POD), and glutathione reductase (GR) in the roots and shoots of Trigonella-foenum graecum. The genotoxicity study showed the induction of chromosomal aberrations in root tip cells of the Trigonella foenum-graecum test system. The present study revealed the induction of oxidative stress and genotoxicity of EMRs exposure in the test system.
... This was evident based on the activity analysis of the three enzymes studied, which was elevated up to five times as in the case of G-POD after applying 20 Gy of X-rays. Our results are in agreement with several other studies related to the antioxidant defense system in higher plants (Barbasz et al. 2016;Chandel et al. 2017). Nanoparticles and electromagnetic radiation have various chemical effects, including causing deterioration in large molecules in cells and imbalance in ionic equilibrium leading to generation of hazardous by-products, known as reactive oxygen species (ROS), during biological reactions (Dietz and Herth 2011;Kıvrak et al. 2017). ...
This study aimed to analyze the effect of various mutagens on the in vitro development, physiological activity, acclimatization efficiency, and genetic integrity of Lamprocapnos spectabilis 'Valentine'. Gold nanoparticles (AuNPs), microwaves, and X-rays were used at different doses. The profiles of primary and secondary metabolites and the enzymatic activity in the produced plants were studied. The usefulness of various genetic markers in the detection of mutations in the species was compared. The genome size of L. spectabilis was estimated for the first time. It was found that the addition of AuNPs into the culture medium had a positive impact on the in vitro development and multiplication of plants. All of the shoots regenerated adventitious roots, but plants subjected to the longest microwave irradiation (3 × 9 s) and the non-treated control had the lowest acclimatization efficiency. Application of mutagens significantly affected the activity and profile of most enzymes and phytochemicals studied, however, the final effect depended on the agent type and dose. Mutations were detected by DAMD, RAPD, and SCoT markers in 7.5% of plants, but not by ISSRs. Phenotype variation in leaf shape was found in four plants. The genome size of L. spectabilis was found to be very small; about 1281 Mbp. Key message Gold nanoparticles improve the micropropagation and acclimatization efficiencies in bleeding heart-a species of very small genome size. X-rays, on the other hand, are the most suitable for inducing phenotypical changes. Microwaves are the least useful for both propagation and breeding purposes.
... The behaviour and end-result of radioactive materials in the ecological environment influence the ecosystem (mainly on the growth of plants and animals) [10][11]. In 2017, phone electromagnetic field radiations test (EM-r) have proved that EM-r caused oxidative damage to plant roots [12]. Some studies have indicated that long-term growth of plants in the irradiation area may lead to changes in genetic information, such as leaf thickness, plant development and organ growth, etc. [13][14]. ...
... After the treatment (n=6) with various concentration of the extract (0.2, 0.5, 1, 5, and 10 mg/ml), 1% DMSO and 3% H 2 O 2 , the roots were incubated in Schiff's reagent for 2 h. Then, the roots were washed with 0.5% (w/v) K 2 S 2 O 5 (prepared in 0.05M HCl) solution for 20 min, leading to the visualization of the Malondialdehyde which is a possible product of the lipid peroxidation [13,21]. ...
Objective: The study is to evaluate the possible genotoxic and antigenotoxic potential of Lagenandra toxicaria rhizome methanol extract using Allium cepa root tip assay. Methods: The rhizome methanol extract was prepared using Soxhlet apparatus. The A. cepa roots were treated with various concentrations of the extract at different time points and stained with aceto-orcein. The mitotic index (MI) was calculated. Results: A significant decrease in MI and increase in the percentage of clastogenicity was observed in a time- and dose-dependent manner in the roots treated with the extract at 0.2 mg/ml, 0.5 mg/ml, 1 mg/ml, 5 mg/ml, and 10 mg/ml concentration for 1, 2, and 4 h. The field emission scanning electron microscopy and Fourier-transform infrared spectroscopy revealed evident morphological and biochemical changes at 10 mg/ml treatment when compared to control for 4 h. The agarose gel electrophoresis showed loss of DNA integrity at 10 mg/ml extract for 4 h. In situ histochemical staining by Schiff’s reagent and nitroblue tetrazolium confirmed the increased lipid peroxidation and free radical generation at 4 h treatment. Subsequently, the possible antigenotoxic potential of the plant extract was explored using H2O2 standard assays. The increased percentage of H2O2 induced nuclear lesions was reduced significantly after the modulatory treatment with extract. Conclusion: The L. toxicaria rhizome methanol extract acts as an antigenotoxic agent at lower doses and at higher doses the extract induces clastogenic effects. Further studies are needed to unravel the active component in the extract that mediates the observed phenomenon in the current study.
... After the treatment (n=6) with various concentration of the extract (0.2, 0.5, 1, 5, and 10 mg/ml), 1% DMSO and 3%H 2 O 2 , the roots were incubated in schiff's reagent for two hours. Then the roots were washed with 0.5% (w/v) K 2 S 2 O 5 (prepared in 0.05M HCl) solution for 20 minutes, leading to the visualisation of the Malondialdehyde which is a possible product of the lipid peroxidation [5,37]. ...
This study is the first ever approach to evaluate the possible genotoxic effect of the Lagenandra toxicaria rhizome methanol extract and its antigenotoxic potency against 3% H 2 O 2 induced genetic damage on Allium cepa root tip model. The assay revealed a significant decrease in mitotic index (MI) and an increase in the percentage of clastogenicity in a time and dose-dependent manner in the roots exposed to Lagenandra toxicaria extract at 0.2 mg/ml, 0.5 mg/ml, 1 mg/ml, 5 mg/ml and 10 mg/ml concentration for 1, 2 and 4hour. The ultra structures of cell surface and biochemical changes of the cells were assessed in four hour treated roots using Field emission scanning electron microscopy (FESEM) and Fourier-transform infrared spectroscopy (FTIR). The higher dose of 10 mg/ml treated roots showed an evident morphological as well as biochemical changes compared to the control. The agarose gel electrophoresis showed the loss of DNA integrity in the roots that were treated with 10 mg/ml extract for four hours, where as the control showed comparatively intact DNA bands. The in situ histochemical staining by Schiff’s reagent and nitroblueterasolium (NBT) confirmed the increased lipid peroxidation and free radical generation in four hour treated samples. Subsequently, the possible antigenotoxic potential of the plant extract was explored at its lower doses using H 2 O 2 standard assays. The H 2 O 2 treatment induced nuclear lesions in 93.45 ± 2.33% cells and it was seen to be reduced significantly (50.99 ±7.59 % and 37.13 ± 2.66 %) after the treatment with lower concentration of 0.01 mg/ml and 0.02 mg/ml extract respectively. This suggest that the Lagenandra toxicaria rhizome methanol extract acts as antigenotoxic agent at lower doses but at higher doses the extract induces clastogenic effects and thus acts like a janus-faced compound.
... However, studies relating ROS production and cyto-/genotoxicity in plants per se on EO treatment are largely lacking. Nevertheless, studies have co-related ROS overproduction and cytotoxicity and genotoxicity under the influence of Pb (Pourrut et al., 2011;Kaur et al., 2014) and electromagnetic field radiations (Chandel et al., 2017(Chandel et al., , 2019. ...
... Since the effective resistance of cell membrane has been inversely correlated to frequency (Lvovich, 2012), therefore, the greater damage to cells and tissues was observed at 1800 MHz than at 900 MHz. Previously, studies demonstrated that EMF-r and cell phone radiations inhibit root growth, alter biochemical processes, and induce free radical-mediated oxidative damage (Tkalec et al., 2005(Tkalec et al., , 2009Sharma et al., 2009;Singh et al., 2012;Kumar et al., 2016;Chandel et al., 2017). In our study, we observed that roots were thickened upon exposure to EMF-r. ...
... EMF-r affect plants at morphological (Cretescu et al. 2013;Stefi et al. 2017), physiological (Kumar et al. 2016), biochemical (Singh et al. 2012), and molecular (Roux et al. 2008) levels. EMF-r have also been documented to alter the oxidative metabolism in plants (Sharma et al. 2009;Chandel et al. 2017). Recently, Stefi et al. (2018) demonstrated accumulation of secondary metabolites, decreased photosynthetic pigment content, induction of oxidative stress, and a significant rise of L-DOPA decarboxylase in myrtle leaves exposed to 1800 MHz radiations for 30 min at intervals of 48 h for 50 days. ...
The present study evaluated the potential of 2100 MHz radiofrequency radiations to act as cytotoxic and genotoxic agent. Fresh onion (Allium cepa L.) roots were exposed to electromagnetic field radiations (EMF-r) for different durations (1 h and 4 h) and evaluated for mitotic index (MI), phase index, chromosomal aberrations, and DNA damage. DNA damage was investigated with the help of the comet assay by assessing various parameters like % head DNA (HDNA), % tail DNA (TDNA), tail moment (TM), and olive tail moment (OTM). Effects of EMF-r exposure were also compared with that of methyl methanesulfonate (MMS; 90 μM), which acted as a positive control. The post-exposure effects of EMF-r after providing the test plants with an acclimatization period of 24 h were also evaluated. Compared to the control, a significant increase in the MI and aberration percentage was recorded upon 4 h of exposure. However, no specific trend of phase index in response to exposure was detected. EMF-r exposure incited DNA damage with a significant decrease in HDNA accompanied by an increase in TDNA upon exposure of 4 h. However, TM and OTM did not change significantly upon exposure as compared to that of control. Analysis of the post-exposure effects of EMF-r did not show any significant change/recovery. Our data, thus, suggest the potential cytotoxic and genotoxic nature of 2100 MHz EMF-r. Our study bears great significance in view of the swiftly emergent EMF-r in the surrounding environment and their potential for inciting aberrations at the chromosomal level, thus posing a genetic hazard.
... Although understanding about effects of CP on plant physiology is vague, several studies focused on radio-frequency EMF irradiation-induced gene expression regulation in plant cells were published previously (reviewed by 46 ) and demonstrated that direct exposure to low power high frequency EMF radiation evokes changes in plant gene expression and modifies numerous metabolic activities (reactive oxygen species metabolism, Krebs cycle, pentose phosphate pathway, chlorophyll content, terpene emission, and gene expression) [46][47][48][49][50] . Further, it has been demonstrated that the response could occur not only in directly exposed tissues but could spread systemically to unaffected tissues through Ca 2+ mediated signalling 51 . ...
Treatment of plant seeds with electromagnetic fields or non-thermal plasmas aims to take advantage of plant functional plasticity towards stimulation of plant agricultural performance. In this study, the effects of pre-sowing seed treatment using 200 Pa vacuum (7 min), 5.28 MHz radio-frequency cold plasma (CP −2, 5, and 7 min) and electromagnetic field (EMF −5, 10, 15 min) on seed germination kinetics, content of phytohormones, morphometric parameters of seedlings and leaf proteome were assessed. CP 7 min and EMF 15 min treatments caused 19–24% faster germination in vitro; germination in the substrate was accelerated by vacuum (9%) and EMF 15 min (17%). The stressors did not change the seed germination percentage, with exception of EMF 5 min treatment that caused a decrease by 7.5%. Meanwhile both CP 7 min and EMF 15 min treatments stimulated germination, but the EMF treatment resulted in higher weight of leaves. Stressor-specific changes in phytohormone balance were detected in seeds: vacuum treatment decreased zeatin amount by 39%; CP treatments substantially increased gibberellin content, but other effects strongly varied with the treatment duration; the abscisic acid content was reduced by 55–60% after the EMF treatment. Analysis of the proteome showed that short exposure of seeds to the EMF or CP induced a similar long-term effect on gene expression in leaves, mostly stimulating expression of proteins involved in photosynthetic processes and their regulation.
The biological effects of exposure to electromagnetic fields due to wireless technologies and connected devices are a subject of particular research interest. Ultrashort high-amplitude electromagnetic field pulses delivered to biological samples using immersed electrodes in a dedicated cuvette have widely demonstrated their effectiveness in triggering several cell responses including increased cytosolic calcium concentration and reactive oxygen species (ROS) production. In contrast, the effects of these pulses are poorly documented when electromagnetic pulses are delivered through an antenna. Here we exposed Arabidopsis thaliana plants to 30,000 pulses (237 kV m-1 , 280 ps rise-time, duration of 500 ps) emitted through a Koshelev antenna and monitored the consequences of electromagnetic fields exposure on the expression levels of several key genes involved in calcium metabolism, signal transduction, ROS, and energy status. We found that this treatment was mostly unable to trigger significant changes in the messenger RNA accumulation of calmodulin, Zinc-Finger protein ZAT12, NADPH oxidase/respiratory burst oxidase homolog (RBOH) isoforms D and F, Catalase (CAT2), glutamate-cystein ligase (GSH1), glutathione synthetase (GSH2), Sucrose non-fermenting-related Kinase 1 (SnRK1) and Target of rapamycin (TOR). In contrast, Ascorbate peroxidases APX-1 and APX-6 were significantly induced 3 h after the exposure. These results suggest that this treatment, although quite strong in amplitude, is mostly ineffective in inducing biological effects at the transcriptional level when delivered by an antenna. © 2023 The Authors. Bioelectromagnetics published by Wiley Periodicals LLC on behalf of Bioelectromagnetics Society.
Penggunaan telepon seluler telah menjadi kebiasaan dan kebutuhan masyarakat modern saat ini. Penggunaan telepon seluler khususnya dalam menelpon sering kali diletakkan pada kepala kanan. Penggunaan ini dapat memberikan dampak kepada hipokampus, salah satunya pada daerah CA1 yang berfungsi untuk membentuk proses ingatan jangka panjang. Tujuan dari penelitian ini adalah untuk mengetahui dampak paparan gelombang elektromagnetik telepon seluler 3G dan 4G pada lapisan piramidalis CA1 hipokampus model hewan coba mencit. Penelitian ini dilakukan secara eksperimental, menggunakan mencit galur Mus musculus jantan, dengan jumlah total sampel sebanyak 32 mencit. Mencit dibagi menjadi 4 kelompok: kelompok kontrol, kelompok Sham, kelompok perlakuan I (P1), dan kelompok perlakuan II (P2). Perlakuan yang diberikan yaitu berupa paparan 3G dan 4G yang dilakukan 1 jam setiap hari selama 30 hari. Variabel yang diteliti adalah ketebalan lapisan dan jumlah neuron pada lapisan piramidal area CA1 hipokampus mencit. Kemudian otak diambil dan dibuat sediaan histologi menggunakan pewarnaan haematoxylin-eosin dan diamati menggunakan mikroskop cahaya pembesaran 400x serta menggunakan software Cell Sens. Analisis data dilakukan dengan uji Anova satu arah dan uji beda nyata terkecil. Hasil penelititan didapatkan bertambahnya ketebalan lapisan piramidal serta berkurangnya rerata jumlah neuron piramidal area CA1 hipokamopus pada kelompok yang diberikan paparan. Setelah dilakukan analisis statistik, tidak terdapat perbedaan bermakna antar kelompok pada ketebalan lapisan piramidalis area CA1 hipokampus serta terdapat perbedaan yang signifikan rerata jumlah neuron piramidal kelompok yang diberikan paparan dan tidak.
Numerous studies report different types of responses following exposure of plants to high frequency electromagnetic fields (HF-EMF). While this phenomenon is related to tissue heating in animals, the situation is much less straightforward in plants where metabolic changes seem to occur without tissue temperature increase. We have set up an exposure system allowing reliable measurements of tissue heating (using a reflectometric probe and thermal imaging) after a long exposure (30 min) to an electromagnetic field of 2.45 GHz transmitted through a horn antenna (about 100 V m-1 at the plant level). We did not observe any heating of the tissues, but we detected rapid increases (60 min) in the accumulation of transcripts of stress-related genes (TCH1 and ZAT12 transcription factor) or involved in ROS metabolism (RBOHF and APX1). At the same time, the amounts of hydrogen peroxide and dehydroascorbic acid increased while glutathione (reduced and oxidized forms), ascorbic acid, and lipid peroxidation remained stable. Therefore, our results unambiguously show that molecular and biochemical responses occur rapidly (within 60min) in plants after exposure to an electromagnetic field, in absence of tissue heating.
Rhizosphere is the most important ecological niche, which plays a vital role by acting as a connecting link between plant, soil and microbes. Rhizo-deposits are the secretions released by the plant roots in the form of root exudates, border cells of roots and other rhizo-deposits. These secretions mostly include low molecular weight bioactive organic compounds, which may attract various beneficial microbes like PGPR (plant growth promoting rhizobacteria), PGPF (plant growth promoting fungi) for their colonization and some of them also contain antimicrobial defensive compounds that repel various deleterious or plant pathogenic microorganisms. Among several forms of benefits derived from rhizo-deposits, root exudates that help in attracting and harbouring various beneficial microbes like rhizobacteria and fungal bio-agents, play a crucial role in the suppression of various soil borne plant pathogens, insect pests, nematodes and harmful microbes apart from their growth promoting activities. These PGPR, PGPF, and various microorganisms with bio-control potential exhibit excellent colonizing ability with the roots and even some of them establish symbiotic and endophytic relationship with plants. These beneficial microbes colonizing the rhizosphere zone exhibit various types of mechanisms like nutrient solubilization by supplying water and inorganic mineral nutrients in the available form to the plant. They exhibit various defence mechanisms like hyper-parasitism, competition, antibiosis and induced systemic resistance response in plants against plant pathogenic and harmful microbes. In addition to these bio-control activities, these beneficial microbes like PGPR’s and PGPF’s present in the rhizosphere region help in the enhancement of plant growth parameters like shoot and root length, shoot and root biomass, chlorophyll content, vigour, flowering, fruiting and ultimately yield of plants. They also help in alleviating several abiotic stress in plants such as water scarcity, submergence and salinity. This chapter provides the insights into, how bacterial and fungal biocontrol agents help the crop plants in combating several biotic and abiotic stresses through several morphological and phsiological changes in the crop due to application of biocontrol agents and also that how these microorganisms help plants in increasing their growth and vigour. How root exudates help in colonization of various rhizosphere-inhabiting microorganisms and how application of various organic substrates and de-oiled cakes in the rhizosphere zone help in the population build-up and establishment of these beneficial microbes in the rhizosphere zone.
The high frequency electromagnetic (EM) waves have been proven as potent environmental polluters. The radio towers are considerably increasing to cater to the growing telecommunication requirements. The presented research focuses on the investigation of EM waves on antimicrobial potential of pharmaceutically important medicinal plants viz. Tulsi (Ocimum sanctum L.) and Brahmi (Bacopa monnieri). The similar work has not been reported till date at the best of our knowledge. The medicinal plants were exposed to EM waves of 900 MHz possessing a 1.9 mG magnetic field. Our former investigation on plant physiology gave deteriorative effects on selected plants physiology in terms of growth, chlorophyll content, protein and carbohydrate content. In the presented article, the antimicrobial activity of two plants was inspected through various bacterial and fungal species. In case of B. monnieri, investigations revealed raise in Zone of Inhibition (ZOI) for both the bacterial and fungal strains in the range of 50%, whereas for O. sanctum increase of 63.26% and 59.42% ZOI for bacterial and fungal strains were noted respectively upon 24 h of exposure. Minimum Inhibitory Concentration (MIC) also decreased for 24 and 48 h of exposure. The transient raise in antimicrobial activity indicated the induction of plant defense system which can be considered as positive influence of short term radiation on medicinal properties of plants. Both plants exhibited the highest antimicrobial potential for E. coli and P. chrysogenum showing a prominent decline after 72 h of exposure. A substantial decline in antimicrobial in MIC of B. monnieri reported was 211% against E. coli and 166% against P. chrysogenum upon 144 h of exposure compared to control plants. The antimicrobial potential of O. sanctum was also decreased upon radiation, which is having a 392% reduction against E. coli and a 225% reduction against P. chrysogenum upon 144 h of exposure. The noteworthy deteriorative effects of radio waves on antimicrobial potential have been observed for both the medicinal plants.
The Globe is marching towards the development of the telecommunication field which leads to increment of non-ionizing radiation in the environment which affects all living beings including plants grown nearby to communication base stations. The present research was focused on physiological and biochemical alterations of tomato plants exposed to high-frequency radiation. The overall plant health was analyzed by physiological changes viz., plant height, size of leaves, length to the root system, and rate of germination upon exposure of radiation and shown significant reduction (p < 0.05) compared to control. Consecutively, radiation also negatively affects the photosynthetic pigment content of leaves which has shown significant reduction. Yet another confirmation of stress on exposed plant tissue was reported by obtaining higher H2O2 content within exposed plant leaf than the control. The morphological alterations viz. curling of leaves, discoloration, and size reduction became more prominent with an increase in the exposure time. The significant outcomes denoted according to 95% confidence limit. There was a significant decline in total phenolic content (37.06%), flavonoid content (71.38%), Vitamin C content (72.45%), and DPPH (59.32%) as well as total antioxidant assays (71.89%) which revealed significant deteriorative effects on such waves on secondary metabolites and the antioxidant potential of tomato plants. The lycopene content was continuously increasing up to 73.13% upon radiation of 120 h and such raise was the direct indication of harmful effect on fruit skin and release of lycopene due to softening of the fruit tissue. Thus, the presented findings illustrated the negative effects of such waves on the quality of tomato plants. The limited insight of metabolic pathways involved in plant responses to such non-ionizing radiation makes such investigation worth in agricultural application. Additionally, mobile communication agencies should be informed and installation of base stations for mobile communication towers should be prohibited at agricultural lands.
Electromagnetic fields (EMFs) could induce oxidative stress (OS) in human tissues. Lipid peroxidation (LPO) is the main hallmark of OS that harms neural cell components, primarily lipids in the myelin sheaths and membranes. Vitamin E is a lipophilic antioxidant that protects cells from OS-related damages and inhibits the LPO process. In this study, male rats were assigned into three groups of Control, EMF, and EMF+ Vitamin E. The EMF producer equipment produced an alternate current of 50 Hz, 3 Mili Tesla (mT). At the end of the experiment, half of the substantia nigra in every sample was used for measurement of the malondialdehyde (MDA) level as the end-product of the LPO and activity of superoxide dismutase (SOD) enzyme. The next half of the tissue was prepared for transmission electron microscopy (TEM). In the EMF group, MDA level was enhanced and SOD value decreased significantly compared to the control group, but Vitamin E could restore these changes. In rats undergone EMF, heterochromatic nucleus and destruction in some portions of the nuclear membrane were detected. The segmental separation or destruction of myelin sheath lamellae was observed in nerve fibers. In treated animals, the nucleus was round, less heterochromatic, with a regular membrane. Separation of myelin sheath lamellae in some nerve fibers was slighter than the radiation group. Considering the results, EMF exposure induces LPO and triggers ultrastructural changes in the cell membranes, nucleus, and myelin sheath of substantia nigra cells, but Vitamin E consumption weakens these neuropathological alterations.
Although cell phones have used worldwide, but some adverse and toxic effects were reported for this communication technology apparatus. To analyze in vivo effects of exposure to radiofrequency-electromagnetic field (RF-EMF) on protein expression in rat testicular proteome, 20 Sprague-Dawley rats were exposed to 900 MHz RF-EMF for 0, 1, 2, or 4 h/day for 30 consecutive days. Protein content of rat testes were separated by high-resolution 2 dimensional electrophoresis using immobilized pH gradient (pI 4-7, 7 cm) and 12% acrylamide and identified by MALDI-TOF/TOF-MS. Two protein spots were found differentially overexpressed (P<0.05) in intensity and volume with induction factors 1.7 times greater after RF-EMF exposure. After 4 hours of daily exposure for 30 consecutive days, ATP synthase beta subunit (ASBS) and hypoxia up-regulated protein 1 precursor (HYOU1) were found to be significantly up-regulated. These proteins affect signaling pathways in rat testes and spermatogenesis and play a critical role in protein folding and secretion in the endoplasmic reticulum. Our results indicate that exposure to RF-EMF produces increases in testicular proteins in adults that are related to carcinogenic risk and reproductive damage. In light of the widespread practice of men carrying phones in their pockets near their gonads, where exposures can exceed as-tested guidelines further study of these effects should be a high priority.
High frequency nonionizing electromagnetic fields (HF-EMF) that are increasingly present in the environment constitute a genuine environmental stimulus able to evoke specific responses in plants that share many similarities with those observed after a stressful treatment. Plants constitute an outstanding model to study such interactions since their architecture (high surface area to volume ratio) optimizes their interaction with the environment. In the present review, after identifying the main exposure devices (transverse and gigahertz electromagnetic cells, wave guide, and mode stirred reverberating chamber) and general physics laws that govern EMF interactions with plants, we illustrate some of the observed responses after exposure to HF-EMF at the cellular, molecular, and whole plant scale. Indeed, numerous metabolic activities (reactive oxygen species metabolism,
α
- and
β
-amylase, Krebs cycle, pentose phosphate pathway, chlorophyll content, terpene emission, etc.) are modified, gene expression altered (calmodulin, calcium-dependent protein kinase, and proteinase inhibitor), and growth reduced (stem elongation and dry weight) after low power (i.e., nonthermal) HF-EMF exposure. These changes occur not only in the tissues directly exposed but also systemically in distant tissues. While the long-term impact of these metabolic changes remains largely unknown, we propose to consider nonionizing HF-EMF radiation as a noninjurious, genuine environmental factor that readily evokes changes in plant metabolism.
In this study, the effects of electromagnetic waves emitted from mobile phones operating at 1800 MHz were investigated on germination, root growth and mitotic division of root tips of Lens culinaris Medik. Seeds were split into three groups. The first group was exposed to a mobile phone electromagnetic field for 48 hours at the state of dormancy, and the second group was exposed to the same electromagnetic field at the state of division. The third group, the control group, was not exposed to an electromagnetic field beyond the natural background. The results obtained in the study indicate that electromagnetic waves emitted from mobile phones affect seeds in the state of dormancy more than the state of germination. Germination rate was not affected under the specified exposure conditions, but root growth decreased due to a possible effect of oxidative stress in the state of dormant seeds. There was also a noticeable increment in the c-mitosis rates, especially in the state of dormant seeds. The reason for this increment could be problems in spindle function.
The aim of this study was to investigate the effects of 900 and 1800 MHz electromagnetic field (EMF) emitted by base station antennas implementing the mobile telephone communication on electrocardiogram (ECG) and some biochemical parameters. Animal material was consisted of 26 male guinea pigs, weighing 652±22.8 g in average. Animals were divided into three groups, as group 1 (control n=7), group 2 (900 MHz EMF n=10) and group 3 (1800 MHz EMF n=9). Groups 2 and 3 were subjected to EMF for 20 days, daily between 13:00-17:00 pm for 4. Total protein (TP), albumin, globulin, plasma oxidant status (TOS), total antioxidant capacity (TAC) and Nitric Oxide (NO) levels were determined in plasma. Statistical comparision of data obtained from plasma analysis revealed a significant difference in guinea pigs subjected to 900 and 1800 MHz radioactive field for albumin, globulin and TOS levels (P<0.05). NO reflected a significant difference in 900 MHz EMF subjected guinea pigs, compared to the control group (P<0.05), however no differences were observed in 1800 MHz EMF subjected animals. Data obtained from ECG and plasma analysis indicated that EMF subjection may lead to some irregularities in the autonomic control of the heart in addition to oxidative damage.
The increasing use of mobile phones and wireless networks raised a great debate about the real carcinogenic potential of radiofrequency-electromagnetic field (RF-EMF) exposure associated with these devices. Conflicting results are reported by the great majority of in vivo and in vitro studies on the capability of RF-EMF exposure to induce DNA damage and mutations in mammalian systems. Aimed at understanding whether less ambiguous responses to RF-EMF exposure might be evidenced in plant systems with respect to mammalian ones, in the present work the mutagenic effect of RF-EMF has been studied through the micronucleus (MN) test in secondary roots of Vicia faba seedlings exposed to mobile phone transmission in controlled conditions, inside a transverse electro magnetic (TEM) cell. Exposure of roots was carried out for 72h using a continuous wave (CW) of 915 MHz radiation at three values of equivalent plane wave power densities (23, 35 and 46W/m(2)). The specific absorption rate (SAR) was measured with a calorimetric method and the corresponding values were found to fall in the range of 0.4-1.5W/kg. Results of three independent experiments show the induction of a significant increase of MN frequency after exposure, ranging from a 2.3-fold increase above the sham value, at the lowest SAR level, up to a 7-fold increase at the highest SAR. These findings are in agreement with the limited number of data on cytogenetic effects detected in other plant systems exposed to mobile phone RF-EMF frequencies and clearly show the capability of radiofrequency exposure to induce DNA damage in this eukaryotic cell system.
Current technologies have become a source of omnipresent electromagnetic pollution from generated electromagnetic fields and resulting electromagnetic radiation. In many cases this pollution is much stronger than any natural sources of electromagnetic fields or radiation. The harm caused by this pollution is still open to question since there is no clear and definitive evidence of its negative influence on humans. This is despite the fact that extremely low frequency electromagnetic fields were classified as potentially carcinogenic. For these reasons, in recent decades a significant growth can be observed in scientific research in order to understand the influence of electromagnetic radiation on living organisms. However, for this type of research the appropriate selection of relevant model organisms is of great importance. It should be noted here that the great majority of scientific research papers published in this field concerned various tests performed on mammals, practically neglecting lower organisms. In that context the objective of this paper is to systematise our knowledge in this area, in which the influence of electromagnetic radiation on lower organisms was investigated, including bacteria, E. coli and B. subtilis, nematode, Caenorhabditis elegans, land snail, Helix pomatia, common fruit fly, Drosophila melanogaster, and clawed frog, Xenopus laevis.
Our aim was to determine a possible relationship between whole body 900MHz GSM-like electromagnetic field (EMF) exposure and pathological changes in vital organs of Sprague–Dawley rats. Twenty adult male rats were used in four equal independent groups, 5 of which was control (without EMF), 15 of which, according to time of exposure to EMF (1, 2 and 4 h), was divided into three subgroups (low, moderate and high dose), five per each group. The exposures were performed for 30 consecutive days. Tissue samples of heart, liver, and left kidney were collected and fixed at 10% buffered formalin for histopathological examination. Some pathological lesions especially in kidney were seen. Our results demonstrate that the use of GSM-like EMF at these intense and duration
cannot induce pathological lesions in heart, liver or kidney.
The determination of the effects of magnetic field on tissue cultures will be helpfull for the magnetic field treatments. In this study which was begun with this purpose, the seeds belonging to J 357 soybean variety were used. The soybean seeds were germinated in sterile conditions and cultures were initiated from the shoot tips. The explants in petri dishes were exposed to 2.9-4.6 mT magnetic fields for 2.2, 6.6, and 19.8 seconds periods. Shoot and root formation rate, fresh weights and chlorophyll quantities of regenerated shoots from control and treated explants were determined. While the shoot formation was 61.91% in control group, this rate increased in all magnetic field experiments and this rate raised up to 86.96% and 74.36% respectively in the explants which were exposed to magnetic field at 2.2 and 6.6 seconds periods. Again, while the percentage of root formation in control was 14.29%, this rate raised up to 26.08% and 35.90% respectively in these which were exposed to magnetic field at the same periods. When the fresh weights were determined, the fresh weights of seedlings regenerated from treatment explants from 6.6 seconds significantly increased in accordance with control (P
In this study, the mutagenic effects of low power radiofrequency radiation on Zea mays root tip were studied. Cells in different division phases and chromosomal aberration assay were used to determine the mitotic index and chromosomal aberration frequency of Zea mays root tip cells induced by 900MHz radiofrequency radiation. Zea mays seeds, having a uniform genophond, have been exposed to RF field of low power density, for different time intervals, between 1.0 and 36.0 hours. Exposure to RF field was applied to seeds before germination process. Continuous wave on 900 MHz was used for irradiation. Incident field distribution in the irradiation area was characterized, so as an as possible as uniform field to be applied in the volume of the sample. The results showed that the mitotic index and chromosomal aberration frequency showed linear increasing for radiofrequency radiation treatment of increased exposure time.
Active oxygen species (AOS) are believed to have important roles in plants in general and in plant-pathogen interactions in particular. They are believed to be involved in signal transduction, cell wall reinforcement, hypersensitive response (HR) and phytoalexin production, and to have direct antimicrobial effects. Since current methods are inadequate for localizing AOS in intact plant tissue, most studies have been conducted using cell suspension culture/elicitors systems. 3,3-diaminobenzidine (DAB) polymerizes instantly and locally as soon as it comes into contact with H2O2 in the presence of peroxidase, and it was found that, by allowing the leaf to take up this substrate, in-vivo and in-situ detection of H2O2 can be made at subcellular levels. This method was successfully used to detect H2O2 in developing papillae and surrounding haloes (cell wall appositions) and whole cells of barley leaves interacting with the powdery mildew fungus. Thus, H2O2 can be detected in the epidermal cell wall subjacent to the primary germ tube from 6 h after inoculation, and subjacent to the appressorium from 15 h. The earliest time point for observation of H2O2 in relation to epidermal cells undergoing HR is 15 h after inoculation, first appearing in the zones of attachment to the mesophyll cells underneath, and eventually in the entire epidermal cell. Furthermore, it was observed that proteins in papillae and HR cells are cross-linked, a process believed to be fuelled by H2O2. This cross-linking reinforces the apposition, presumably assisting the arrest of the pathogen.
The indiscriminate use of wireless technologies, particularly of cell phones, has increased the health risks among living organisms including plants. We investigated the impact of cell phone electromagentic field (EMF) radiations (power density, 8.55 microW cm(-2)) on germination, early growth, proteins and carbohydrate contents, and activities of some enzymes in Vigna radiata. Cell phone EMF radiations significantly reduced the seedling length and dry weight of V radiata after exposure for 0.5, 1, 2, and 4 h. Furthermore, the contents of proteins and carbohydrates were reduced in EMF-exposed plants. However, the activities of proteases, alpha-amylases, beta-amylases, polyphenol oxidases, and peroxidases were enhanced in EMF-exposed radicles indicating their role in providing protection against EMF-induced stress. The study concludes that cell phone EMFs impair early growth of V radiata seedlings by inducing biochemical changes.
The possibility of detecting lipid peroxidation histochemically was investigated in liver tissue in vivo, in conditions in which the process has been demonstrated by biochemical methods. The technique was based on the detection of aldehyde functions with the use of the Schiff's reagent. The study was carried out on bromobenzene-intoxicated mice, which generally exhibit levels of lipid peroxidation considerably higher than those observed in the case of other hepatotoxins. Liver sections from control animals were unstainable by the reagent, while sections from bromobenzene-poisoned mice showed a purple stain of various intensity, unhomogeneously distributed, sometimes with a mediolobular localization. Microphotometric measurements were performed at 565 nm by means of a computer-controlled microscope photometer. The ratios of Schiff-positive area relative to total section area, as well as the total extinctions referred to 100 sq mu of the sections, showed a high correlation with the corresponding hepatic contents of malonic dialdehyde, chosen as biochemical index of lipid peroxidation. In vitro studies in which liver sections were incubated in the presence of NADPH-Fe2+, showed a Schiff positivity which increased with the incubation time, confirming the reliability of the histochemical method. Another procedure, based on the use of 2-OH-3-naphtoic acid hydrazide coupled with fast blue B, was also developed and proved to be possibly more sensitive than Schiff's reagent in the detection of lipid peroxidation in liver tissue.
FMN and flavodoxin, when reduced by the action of ferredoxin-TPN⁺ oxidoreductase, have been shown to cause both univalent and divalent reductions of oxygen. Superoxide radicals, so generated, were detected by their abilities to oxidize epinephrine to adrenochrome and to reduce cytochrome c. Superoxide dismutase inhibited these actions of the superoxide radical. The ratio of the univalent reduction of oxygen, to the sum of the univalent plus divalent reductions of oxygen, was determined as a function of pH and of oxygen concentration. These data were compared with the results of similar measurements made previously, with ferredoxins and xanthine oxidase. FMN and flavodoxin carry out the univalent reduction of oxygen much less effectively than either xanthine oxidase or the ferredoxins. Furthermore, the univalent reduction of oxygen by xanthine oxidase and by the ferredoxins showed similar responses to changes in pH and oxygen concentration; whereas the behavior of the flavodoxin and FMN mediated systems was distinctly different. These results suggest that the reduction of oxygen by native milk xanthine oxidase may well be a function of its non-heme iron centers.
The fully reduced form of menadione, generated by the action of Diaphorase, caused a predominantly divalent reduction of oxygen; whereas the semiquinone forms of this carrier, generated by the action of the ferredoxin-TPN⁺ oxidoreductase, caused primarily a univalent reduction of oxygen.
15N NMR analysis reveals alanine production in Duckweed plants exposed to low intensity sinusoidally varying magnetic fields (SVMF) at 60 and 100Hz, and fed by 15N-labeled ammonium chloride. Alanine does not accumulate in the absence of SVMF. Addition of vitamin C, a radical scavenger, reduced alanine production by 82%, indicating the roll of free radicals in the process. Alanine accumulation in plants and animals in response to exposure to a variety of stress conditions, including SVMF, is a general phenomenon. It is proposed that alanine is a universal first stress signal expressed by cells.
The biological effect of radiofrequency (RF) fields remains controversial. We address this issue by examining whether RF fields can cause changes in gene expression. We used the pulsed RF fields at a frequency of 2.45 GHz that is commonly used in telecommunication to expose cultured human HL-60 cells. We used the serial analysis of gene expression (SAGE) method to measure the RF effect on gene expression at the genome level. We observed that 221 genes altered their expression after a 2-h exposure. The number of affected genes increased to 759 after a 6-h exposure. Functional classification of the affected genes reveals that apoptosis-related genes were among the upregulated ones and the cell cycle genes among the downregulated ones. We observed no significant increase in the expression of heat shock genes. These results indicate that the RF fields at 2.45 GHz can alter gene expression in cultured human cells through non-thermal mechanism.
The influence of varied Mg supply (10-1000 micromolar) and light intensity (100-580 microeinsteins per square meter per second) on the concentrations of ascorbate (AsA) and nonprotein SH-compounds and the activities of superoxide dismutase (SOD; EC 1.15.11) and the H(2)O(2) scavenging enzymes, AsA peroxidase (EC 1.11.1.7), dehydroascorbate reductase (EC 1.8.5.1), and glutathione reductase (EC 1.6.4.2) were studied in bean (Phaseolus vulgaris L.) leaves over a 13-day period. The concentrations of AsA and SH-compounds and the activities of SOD and H(2)O(2) scavenging enzymes increased with light intensity, in particular in Mg-deficient leaves. Over the 12-day period of growth for a given light intensity, the concentrations of AsA and SH-compounds and the activities of these enzymes remained more or less constant in Mg-sufficient leaves. In contrast, in Mg-deficient leaves, a progressive increase was recorded, particularly in concentrations of AsA and activities of AsA peroxidase and glutathione reductase, whereas the activities of guaiacol peroxidase and catalase were only slightly enhanced. Partial shading of Mg-deficient leaf blades for 4 days prevented chlorosis, and the activities of the O(2) (.-) and H(2)O(2) scavenging enzymes remained at a low level. The results demonstrate the role of both light intensity and Mg nutritional status on the regulation of O(2) (.-) and H(2)O(2) scavenging enzymes in chloroplasts.
Using an especially-designed facility, the Mode Stirred Reverberation Chamber, we exposed tomato plants (Lycopersicon esculentum Mill. VFN8) to low level (900 MHz, 5 V m(-1)) electromagnetic fields for a short period (10 min) and measured changes in abundance of three specific mRNA soon after exposure. Within minutes of electromagnetic stimulation, stress-related mRNA (calmodulin, calcium-dependent protein kinase and proteinase inhibitor) accumulated in a rapid, large and 3-phase manner typical of an environmental stress response. Accumulation of these transcripts into the polysomal RNA also took place (indicating that the encoded proteins were translated) but was delayed (indicating that newly-synthesized mRNA was not immediately recruited into polysomes). Transcript accumulation was maximal at normal Ca(2+) levels and was depressed at higher Ca(2+), especially for those encoding calcium-binding proteins. Removal of Ca(2+) (by addition of chelating agents or Ca(2+) channel blocker) led to total suppression of mRNA accumulation. Finally, 30 min after the electromagnetic treatment, ATP concentration and adenylate energy charge were transiently decreased, while transcript accumulation was totally prevented by application of the uncoupling reagent, CCCP. These responses occur very soon after exposure, strongly suggesting that they are the direct consequence of application of radio-frequency fields and their similarities to wound responses strongly suggests that this radiation is perceived by plants as an injurious stimulus.
Nitro blue tetrazolium has been used to intercept O2⁻ generated enzymically or photochemically. The reduction of NBT by O2⁻ has been utilized as the basis of assays for superoxide dismutase, which exposes its presence by inhibiting the reduction of NBT. Superoxide dismutase could thus be assayed either in crude extracts or in purified protein fractions. The assays described are sensitive to ng/ml levels of super-oxide dismutase and were applicable in free solution or on polyacrylamide gels. The staining procedure for localizing superoxide dismutase on polyacrylamide electrophoretograms has been applied to extracts obtained from a variety of sources. E. coli has been found to contain two superoxide dismutases whereas bovine heart, brain, lung, and erthrocytes contain only one.
A photo-induced cyclic peroxidation in isolated chloroplasts is described. In an osmotic buffered medium, chloroplasts upon illumination produce malondialdehyde (MDA)—a decomposition product of tri-unsaturated fatty acid hydroperoxides—bleach endogenous chlorophyll, and consume oxygen. These processes show (a) no reaction in the absence of illumination; (b) an initial lag phase upon illumination of 10-20 minutes duration; (c) a linear phase in which the rate is proportional to the square root of the light intensity; (d) cessation of reaction occurring within 3 minutes after illumination ceases; and (e) a termination phase after several hours of illumination. The kinetics of the above processes fit a cyclic peroxidation equation with velocity coefficients near those for chemical peroxidation.
The stoichiometry of MDA/O2 = 0.02, and O2/Chlbleached = 6.9 correlates well with MDA production efficiency in other biological systems and with the molar ratio of unsaturated fatty acids to chlorophyll. The energies of activation for the lag and linear phases are 17 and 0 kcal/mole, respectively, the same as that for autoxidation. During the linear phase of oxygen uptake the dependence upon temperature and O2 concentration indicates that during the reaction, oxygen tension at the site of peroxidation is 100-fold lower than in the aqueous phase.
It is concluded that isolated chloroplasts upon illumination can undergo a cyclic peroxidation initiated by the light absorbed by chlorophyll. Photoperoxidation results in a destruction of the chlorophyll and tri-unsaturated fatty acids of the chloroplast membranes.
Potential damage due to cell phones are mostly focused on head and reproductive organs. Effects of 900 MHz electromagnetic field (EMF) exposure on rat serum and testes antioxidant enzyme levels are described. Groups of 5 rats each were exposed for 1h(STE), 2h(MTE), and 4h(LTE) for 30 consecutive days to EMF with average power density of 86mW/cm2 for 30 consecutive days. One group were sham controls. Blood sampling was performed at days 0 and 30, but testicular sampling was performed only on day 30. Serum and testicular superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GRx) were measured. After 30 days exposure, serum SOD or GPx activity declined (P<0.05) in LTE or MTE rats compared with other or sham groups. In testicular tissue, GPx decreased in MTE (259.93±61.77 U/mg) and LTE (235.54±56.90 U/mg) groups compared with controls (677.17±194.96 U/mg) (P<0.05). Results should be interpreted with caution due to small (n=5) sampling values.
Exposure to sustained low intensity microwaves can constitute a stress for the plants, but its effects on plant secondary chemistry are poorly known. We studied the influence of GSM and WLAN-frequency microwaves on emissions of volatile organic compounds and content of essential oil in the aromatic plant Ocimum basilicum L. hypothesizing that microwave exposure leads to enhanced emissions of stress volatiles and overall greater investment in secondary compounds. Compared to the control plants, microwave irradiation led to decreased emissions of β-pinene, α-phellandrene, bornyl acetate, β-myrcene, α-caryophyllene and benzaldehyde, but increased emissions of eucalyptol, estragole, caryophyllene oxide, and α-bergamotene. The highest increase in emission, 21 times greater compared to control, was observed for caryophyllene oxide. The irradiation resulted in increases in the essential oil content, except for the content of phytol which decreased by 41% in the case of GSM-frequency, and 82% in the case of WLAN-frequency microwave irradiation. The strongest increase in response to WLAN irradiation, >17 times greater, was observed for hexadecane and octane contents. Comparisons of volatile compositions by multivariate analyses demonstrated a clear separation of different irradiance treatments, and according to the changes in the volatile emissions, the WLAN-frequency irradiation represented a more severe stress than the GSM-frequency irradiation. Overall, these results demonstrating important modifications in the emission rates, essential oil content and composition indicate that microwave irradiation influences the quality of herbage of this economically important spice plant.
Wireless communication such as cellular telephones and other types of handheld phones working with frequencies of 900MHz, 1800MHz, 2100MHz, 2450MHz have been increasing rapidly. Therefore, public opinion concern about the potential human health hazards of short and long-term effect of exposure to radiofrequency (RF) radiation. Oxidative stress is a biochemical condition, which is defined by the imbalance between reactive oxygen species (ROS) and the anti-oxidative defense. In this review, we evaluated available in vitro and in vivo studies carried out on the relation between RF emitted from mobile phones and oxidative stress. The results of the studies we reviewed here indicated that mobile phones and similar equipment or radars can be thought as a factor, which cause oxidative stress. Even some of them claimed that oxidative stress originated from radiofrequencies can be resulted with DNA damage. For this reason one of the points to think on is relation between mobile phones and oxidative stress. However, more performance is necessary especially on human exposure studies.
Pea (Pisum sativum) roots were treated with aluminum in a calcium solution, and lipid peroxidation was investigated histochemically and biochemically, as well as other events caused by aluminum exposure. Histochemical stainings were observed to distribute similarly on the entire surface of the root apex for three events (aluminum accumulation, lipid peroxidation, and callose production), but the loss of plasma membrane integrity (detected by Evans blue uptake) was localized exclusively at the periphery of the cracks on the surface of root apex. The enhancement of four events (aluminum accumulation, lipid peroxidation, callose production, and root elongation inhibition) displayed similar aluminum dose dependencies and occurred by 4 h. The loss of membrane integrity, however, was enhanced at lower aluminum concentrations and after longer aluminum exposure (8 h). The addition of butylated hydroxyanisole (a lipophilic antioxidant) during aluminum treatment completely prevented lipid peroxidation and callose production by 40%, but did not prevent or slow the other events. Thus lipid peroxidation is a relatively early symptom induced by the accumulation of aluminum and appears to cause, in part, callose production, but not the root elongation inhibition; by comparison, the loss of plasma membrane integrity is a relatively late symptom caused by cracks in the root due to the inhibition of root elongation.
The use of electromagnetic field (EMF) generating apparatuses such as cell phones is increasing, and has caused an interest in the investigations of its effects on human health. We analyzed proteome in preparations from the whole testis in adult male Sprague-Dawley rats exposed for 1, 2 or 4 h/d for 30 consecutive days to 900 MHz EMF radiation, simulating a range of possible human cell phone use. Subjects were sacrificed immediately after the end of the experiment and testes fractions were solubilized and separated via high resolution 2-dimensional electrophoresis, and gel patterns were scanned, digitized and processed. Thirteen of the proteins which found only in sham or in exposure groups were identified by MALDI-TOF/TOF-MS. Among them, heat shock proteins, superoxide dismutase, peroxiredoxin-1 and other proteins related to misfolding of proteins and/or stress were identified. These results demonstrate significant effects of radio-frequency modulated electromagnetic fields (RF-EMF) exposure on proteome, particularly in protein species in the rodent testis, and suggest that a 30 d exposure to EMF radiation induces non-thermal stress in testicular tissue. The functional implication of the identified proteins was discussed.
This work analyzes the effects of radiofrequency-electromagnetic field (RF-EMF) exposure on the reproductive system of male rats, assessed by measuring circulating levels of FSH, LH, inhibin B, activin B, prolactin, and testosterone. Twenty adult male Sprague-Dawley rats (180 ± 10 g) were exposed to 900 MHz RF-EMF in four equal separated groups. The duration of exposure was 1, 2, and 4 h/day over a period of 30 days and sham-exposed animals were kept under the same environmental conditions as the exposed group except with no RF-EMF exposure. Before the exposure, at 15 and 30 days of exposure, determination of the abovementioned hormone levels was performed using ELISA. At the end of the experiment, FSH and LH values of the long time exposure (LTE) group were significantly higher than the sham-exposed group (p < 0.05). Serum activin B and prolactin in the LTE group showed significant increase and inhibin B showed significant decrease than sham and short time exposed (STE) groups after 30 days RF-EMF exposure (p < 0.05). Also, a significant decrease in serum testosterone levels in the LTE group was found compared to short and moderate time exposed (MTE) groups after 30 days RF-EMF exposure (p < 0.05). Results suggest that reproductive hormone levels are disturbed as a result of RF-EMF exposure and it may possibly affect reproductive functions. However, testosterone and inhibin B concentrations as a fertility marker and spermatogenesis were decreased significantly.
The effect of simulated acid rain (AR) (pH 1.8) on H2O2 and malonyldialdehyde (MDA) levels and activities of peroxidase and catalase in bean plants were investigated. The influence of exogenous polyamines spermidine and spermine on these parameters was also studied. AR treatment induced lipid peroxidation and increased level of H2O2 in leaves. Pretreatment with spermidine and spermine prevented these changes. The protective effect of spermine was higher than that of spermidine. The impact of polyamines could be attributed to their acid neutralizing and antioxidant effects, as well as to their ability to stabilize membranes by associating with negatively charged phospholipids. It was also found that AR significantly increased peroxidase and decreased catalase activities at the first hours after treatment. Later, both enzyme activities were enhanced that could contribute to the scavenging and detoxification of active oxygen species.
The goal of this study was to compare the cytotoxic and genotoxic effects of plutonium-239 alpha particles and GSM 900 modulated mobile phone radiation in the Allium cepa test. Three groups of bulbs were exposed to mobile phone radiation during 0 (sham), 3 and 9h. A positive control group was treated during 20min with plutonium-239 alpha-radiation. Mitotic abnormalities, chromosome aberrations, micronuclei and mitotic index were analyzed. Exposure to alpha-radiation from plutonium-239 and exposure to modulated radiation from mobile phone during 3 and 9h significantly increased the mitotic index. GSM 900 mobile phone radiation as well as alpha-radiation from plutonium-239 induced both clastogenic and aneugenic effects. However, the aneugenic activity of mobile phone radiation was more pronounced. After 9h of exposure to mobile phone radiation, polyploid cells, three-groups metaphases, amitoses and some unspecified abnormalities were detected, which were not registered in the other experimental groups. Importantly, GSM 900 mobile phone radiation increased the mitotic index, the frequency of mitotic and chromosome abnormalities, and the micronucleus frequency in a time-dependent manner. Due to its sensitivity, the A. cepa test can be recommended as a useful cytogenetic assay to assess cytotoxic and genotoxic effects of radiofrequency electromagnetic fields.
The present work describes the effect of low level continuous microwaves (2.45 GHz) on developing rat brain. Some 35-day-old Wistar rats were used for this study. The animals were exposed 2 hr/day for 35 days at a power density of 0.34 mW/cm2 [specific absorption rate (SAR), 0.1 W/kg] in a specially made anechoic chamber. After the exposure, the rats were sacrificed and the brain tissue was dissected out and used for various biochemical assays. A significant increase in calcium ion efflux and ornithine decarboxylase (ODC) activity was observed in the exposed group as compared to the control. Correspondingly, a significant decrease in the calcium-dependent protein kinase activity was observed. These results indicate that this type of radiation affects the membrane bound enzymes, which are associated with cell proliferation and differentiation, thereby pointing out its possible role as a tumor promoter.
Synchronized Chinese hamster ovary (CHO) cells were exposed to continuous wave (CH) 2.45 GHz microwave radiation (MWR) or CW 27 MHz radiofrequency radiation (RFR) under isothermal conditions (37±0.2°) to test the following hypotheses: (1) high frequency electromagnetic radiation exposure directly affects the mammalian cell cycle in the absence of radiation-induced heating; and (2) the magnitude of the cell cycle alteration is frequency dependent. CHO cells in either G0/G1-, S−, or G2/M-phase of the cell cycle were simultaneously exposed to CW 27 MHz RFR or CW 2.45 GHz MWR at specific absorption rates (SARs) of 5 or 25 W kg⁻¹, or sham exposed, at 37±0.2°C. Cell cycle alterations were determined by flow cytofluorometry over a 4 d period after exposure. The DNA distributions of RFR, MWR, and sham exposed cells were compared to detect qualitative effects on the cell cycle. Quantitative measures of the effects of isothermal radiation exposure were determined from differences in the number of exposed and sham exposed cells in various cell cycle phases as well as comparison of the mean DNA content of exposed and sham exposed cell samples. Flow cytofluorometric assay precision and accuracy were determined by comparison of DNA distributions of replicate CHO control cell samples and by the use of internal DNA standards.
The purpose of this work was to examine the impact of microwave radiation at fre-quencies ranging within (2.45-54) GHz on selected potato plant life processes. Completed re-search allowed to find positive impact of microwave radiation at frequency 2.45 GHz on the weight of irradiated seed potato germs, and on the weight of Felka Bona variety potato tubers crop. This impact was not observed for microwave radiation at the following frequencies: 38 GHz, 46 GHz, and 54 GHz.
During the last couple of decades, there has been a tremendous increase in the use of cell phones. It has significantly added to the rapidly increasing EMF smog, an unprecedented type of pollution consisting of radiation in the environment, thereby prompting the scientists to study the effects on humans. However, not many studies have been conducted to explore the effects of cell phone EMFr on growth and biochemical changes in plants. We investigated whether EMFr from cell phones inhibit growth of Vigna radiata (mung bean) through induction of conventional stress responses. Effects of cell phone EMFr (power density: 8.55 µW cm− 2; 900 MHz band width; for ½, 1, 2, and 4 h) were determined by measuring the generation of reactive oxygen species (ROS) in terms of malondialdehyde and hydrogen peroxide (H2O2) content, root oxidizability and changes in levels of antioxidant enzymes. Our results showed that cell phone EMFr significantly inhibited the germination (at ≥2 h), and radicle and plumule growths (≥1 h) in mung bean in a time-dependent manner. Further, cell phone EMFr enhanced MDA content (indicating lipid peroxidation), and increased H2O2 accumulation and root oxidizability in mung bean roots, thereby inducing oxidative stress and cellular damage. In response to EMFr, there was a significant upregulation in the activities of scavenging enzymes, such as superoxide dismutases, ascorbate peroxidases, guaiacol peroxidases, catalases and glutathione reductases, in mung bean roots. The study concluded that cell phone EMFr inhibit root growth of mung bean by inducing ROS-generated oxidative stress despite increased activities of antioxidant enzymes.
The problem of studying the interaction between electromagnetic fields and biological systems can be approached from both theoretical and experimental points of view. In this work, a theoretical model based on experimental results has been introduced in order to study the exposure of neuronal cells to radio frequency (RF) fields. The model proposed is based on linking together two different levels of the biological scale, the level of the single ionic channel of the membrane and the level of the whole cellular membrane. Specific electromagnetic signals have been considered: in particular pulsed signals and continuous wave signals. Results have shown that the effect of the electromagnetic exposure can be regarded as a variation from the physiological situation of less than 6%.
The effects of seed pretreatment by magnetic field (MF) on the impacts of ultraviolet-B (UV-B) radiation were tested using cucumber (Cucumis sativus) seedlings in phytotron. Soaked cucumber seeds were placed in MF of various strengths (0, 0.2 and 0.45 T). After germination the seeds were sowed in homogeneous garden soil and grown, then cucumber seedlings were exposed to 0 (as control) and 3.5 kJ m−2 UV-B irradiation, respectively. Some effects of UV-B radiation and MF-pretreatment as well as their combination were investigated. MF-pretreatment increased seed germination rate, seedling growth and development, although also increased lipid oxidation and ascorbic acid contents. On the other hand, our results provided evidence that seed MF-pretreatment increased the sensitivity of cucumber seedlings to UV-B radiation. The seedling growth and development were significantly decreased by the combination of UV-B irradiation and MF-pretreatment. This combination also increased oxidative pressure and decreased actual quantum yield of PS II. Leaf UV-B absorbing compound was increased by MF-pretreatment or UV-B irradiation, whereas their combination significantly decreased it. These results suggested that the harmful effects of combination were partially due to the inhibition of secondary metabolism.
Potato tuber tissue discs, which were aged after wounding in order to acquire hypersensitive reactivity, reduced extracellular cytochrome c and nitroblue tetrazolium (NBT) following inoculation with an incompatible, but not compatible, race of Phytophthora infestans. The cytochrome c-reducing activity rapidly increased from l to 4 h after inoculation along with an increase in the percentage of hypersensitively dead cells, and then decreased from the time when most of the penetrated cells had died. A localized activation of NBT reduction around invading hyphae of the incompatible, but not those of the compatible, race was observed at early stages of penetration before cell death. The reductive activity of the discs was also elicited by treatment with a hypersensitivity-eliciting substance, hyphal wall components of the fungus.Superoxide dismutase (SOD), an enzyme catalysing the conversion of the superoxide anion (O2−) to H2O2 and O2 inhibited the enhanced reducing activity of the discs when added to the assay solution, indicating that cytochrome c and NBT may be reduced by O2− generated from the discs.Pre-infectional, vacuum infiltration of the discs with a solution containing SOD significantly delayed the occurrence of hypersensitive cell death caused by infection with the incompatible race as well as the accumulation of phytoalexin. Application of SH-binding reagents and NADP+, but not respiratory inhibitors, inhibited the elicitation of the reducing activity caused by infection with the incompatible race.These results indicate that an O2−-generating system may be activated in potato tissues during the incompatible interaction induced by invading fungi or fungal wall components, and also that the generation of O2− may be involved during hypersensitive cell death as a trigger of the sequence of resistance reactions.
Indiscriminate adoption and use of cell phone technology has tremendously increased the levels of electromagnetic field radiations (EMFr) in the natural environment. It has raised the concerns among the scientists regarding the possible risks of EMFr to living organisms. However, not much has been done to assess the damage caused to plants that are continuously exposed to EMFr present in the environment. The present study investigated the biochemical mechanism of interference of 900 MHz cell phone EMFr with root formation in mung bean (Vigna radiata syn. Phaseolus aureus) hypocotyls, a model system to study rhizogenesis in plants. Cell phone EMFr enhanced the activities of proteases (by 1.52 to 2.33 times), polyphenol oxidases (by 1.5 to 4.3 times), and peroxidases (by 1.5 to 2.0 times) in mung bean hypocotyls over control. Further, EMFr enhanced malondialdehyde (an indicator of lipid peroxidation), hydrogen peroxide, and proline content, indicating a reactive oxygen species-mediated oxidative damage in hypocotyls. It was confirmed by the upregulation in the activities of antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, guaiacol peroxidase, catalase, and glutathione reductase) suggesting their possible role in providing protection against EMFr-induced oxidative damage. The study concluded that cell phone radiations affect the process of rhizogenesis through biochemical alterations that manifest as oxidative damage resulting in root impairment.
Various abiotic stresses lead to the overproduction of reactive oxygen species (ROS) in plants which are highly reactive and toxic and cause damage to proteins, lipids, carbohydrates and DNA which ultimately results in oxidative stress. The ROS comprises both free radical (O(2)(-), superoxide radicals; OH, hydroxyl radical; HO(2), perhydroxy radical and RO, alkoxy radicals) and non-radical (molecular) forms (H(2)O(2), hydrogen peroxide and (1)O(2), singlet oxygen). In chloroplasts, photosystem I and II (PSI and PSII) are the major sites for the production of (1)O(2) and O(2)(-). In mitochondria, complex I, ubiquinone and complex III of electron transport chain (ETC) are the major sites for the generation of O(2)(-). The antioxidant defense machinery protects plants against oxidative stress damages. Plants possess very efficient enzymatic (superoxide dismutase, SOD; catalase, CAT; ascorbate peroxidase, APX; glutathione reductase, GR; monodehydroascorbate reductase, MDHAR; dehydroascorbate reductase, DHAR; glutathione peroxidase, GPX; guaicol peroxidase, GOPX and glutathione-S- transferase, GST) and non-enzymatic (ascorbic acid, ASH; glutathione, GSH; phenolic compounds, alkaloids, non-protein amino acids and α-tocopherols) antioxidant defense systems which work in concert to control the cascades of uncontrolled oxidation and protect plant cells from oxidative damage by scavenging of ROS. ROS also influence the expression of a number of genes and therefore control the many processes like growth, cell cycle, programmed cell death (PCD), abiotic stress responses, pathogen defense, systemic signaling and development. In this review, we describe the biochemistry of ROS and their production sites, and ROS scavenging antioxidant defense machinery.
101 publications are exploited which have studied genotoxicity of radiofrequency electromagnetic fields (RF-EMF) in vivo and in vitro. Of these 49 report a genotoxic effect and 42 do not. In addition, 8 studies failed to detect an influence on the genetic material, but showed that RF-EMF enhanced the genotoxic action of other chemical or physical agents. The controversial results may in part be explained by the different cellular systems. Moreover, inconsistencies may depend from the variety of analytical methods being used, which differ considerably with respect to sensitivity and specificity. Taking altogether there is ample evidence that RF-EMF can alter the genetic material of exposed cells in vivo and in vitro and in more than one way. This genotoxic action may be mediated by microthermal effects in cellular structures, formation of free radicals, or an interaction with DNA-repair mechanisms.
The effects of exposure to radiofrequency electromagnetic fields (RF-EMFs) on seed germination, primary root growth as well as mitotic activity and mitotic aberrations in root meristematic cells were examined in Allium cepa L. cv. Srebrnjak Majski. Seeds were exposed for 2h to EMFs of 400 and 900MHz at field strengths of 10, 23, 41 and 120Vm(-1). The effect of longer exposure time (4h) and field modulation was investigated at 23Vm(-1) as well. Germination rate and root length did not change significantly after exposure to radiofrequency fields under any of the treatment conditions. At 900MHz, exposures to EMFs of higher field strengths (41 and 120Vm(-1)) or to modulated fields showed a significant increase of the mitotic index compared with corresponding controls, while the percentage of mitotic abnormalities increased after all exposure treatments. On the other hand, at 400MHz the mitotic index increased only after exposure to modulated EMF. At this frequency, compared with the control higher numbers of mitotic abnormalities were found after exposure to modulated EMF as well as after exposure to EMFs of higher strengths (41 and 120Vm(-1)). The types of aberration induced by the EMFs of both frequencies were quite similar, mainly consisting of lagging chromosomes, vagrants, disturbed anaphases and chromosome stickiness. Our results show that non-thermal exposure to the radiofrequency fields investigated here can induce mitotic aberrations in root meristematic cells of A. cepa. The observed effects were markedly dependent on the field frequencies applied as well as on field strength and modulation. Our findings also indicate that mitotic effects of RF-EMF could be due to impairment of the mitotic spindle.
Nitro blue tetrazolium has been used to intercept O2− generated enzymically or photochemically. The reduction of NBT by O2− has been utilized as the basis of assays for superoxide dismutase, which exposes its presence by inhibiting the reduction of NBT. Superoxide dismutase could thus be assayed either in crude extracts or in purified protein fractions. The assays described are sensitive to ng/ml levels of super-oxide dismutase and were applicable in free solution or on polyacrylamide gels. The staining procedure for localizing superoxide dismutase on polyacrylamide electrophoretograms has been applied to extracts obtained from a variety of sources. E. coli has been found to contain two superoxide dismutases whereas bovine heart, brain, lung, and erthrocytes contain only one.
A photo-induced cyclic peroxidation in isolated chloroplasts is described. In an osmotic buffered medium, chloroplasts upon illumination produce malondialdehyde (MDA)—a decomposition product of tri-unsaturated fatty acid hydroperoxides—bleach endogenous chlorophyll, and consume oxygen. These processes show (a) no reaction in the absence of illumination; (b) an initial lag phase upon illumination of 10–20 minutes duration; (c) a linear phase in which the rate is proportional to the square root of the light intensity; (d) cessation of reaction occurring within 3 minutes after illumination ceases; and (e) a termination phase after several hours of illumination. The kinetics of the above processes fit a cyclic peroxidation equation with velocity coefficients near those for chemical peroxidation.The stoichiometry of MDA/O2 = 0.02, and O2Chlbleached = 6.9 correlates well with MDA production efficiency in other biological systems and with the molar ratio of unsaturated fatty acids to chlorophyll. The energies of activation for the lag and linear phases are 17 and 0 kcal/mole, respectively, the same as that for autoxidation. During the linear phase of oxygen uptake the dependence upon temperature and O2 concentration indicates that during the reaction, oxygen tension at the site of peroxidation is 100-fold lower than in the aqueous phase.It is concluded that isolated chloroplasts upon illumination can undergo a cyclic peroxidation initiated by the light absorbed by chlorophyll. Photoperoxidation results in a destruction of the chlorophyll and tri-unsaturated fatty acids of the chloroplast membranes.
Pea (Pisum sativum) roots were treated with aluminum in a calcium solution, and lipid peroxidation was investigated histochemically and biochemically, as well as other events caused by aluminum exposure. Histochemical stainings were observed to distribute similarly on the entire surface of the root apex for three events (aluminum accumulation, lipid peroxidation, and callose production), but the loss of plasma membrane integrity (detected by Evans blue uptake) was localized exclusively at the periphery of the cracks on the surface of root apex. The enhancement of four events (aluminum accumulation, lipid peroxidation, callose production, and root elongation inhibition) displayed similar aluminum dose dependencies and occurred by 4 h. The loss of membrane integrity, however, was enhanced at lower aluminum concentrations and after longer aluminum exposure (8 h). The addition of butylated hydroxyanisole (a lipophilic antioxidant) during aluminum treatment completely prevented lipid peroxidation and callose production by 40%, but did not prevent or slow the other events. Thus lipid peroxidation is a relatively early symptom induced by the accumulation of aluminum and appears to cause, in part, callose production, but not the root elongation inhibition; by comparison, the loss of plasma membrane integrity is a relatively late symptom caused by cracks in the root due to the inhibition of root elongation.
Widespread use of radiofrequency radiation emitting devices increased the exposure to electromagnetic fields (EMFs) from 300 MHz to 300 GHz. Various biological effects of exposure to these fields have been documented so far, but very little work has been carried out on plants. The aim of the present work was to investigate the physiological responses of the plant Lemna minor after exposure to radiofrequency EMFs, and in particular, to clarify the possible role of oxidative stress in the observed effects. Duckweed was exposed for 2 h to EMFs of 400 and 900 MHz at field strengths of 10, 23, 41 and 120 V m(-1). The effect of a longer exposure time (4 h) and modulation was also investigated. After exposure, parameters of oxidative stress, such as lipid peroxidation, H(2)O(2) content, activities and isoenzyme pattern of antioxidative enzymes as well as HSP70 expression were evaluated. At 400 MHz, lipid peroxidation and H(2)O(2) content were significantly enhanced in duckweed exposed to EMFs of 23 and 120 V m(-1) while other exposure treatments did not have an effect. Compared to the controls, the activities of antioxidative enzymes showed different behaviour: catalase (CAT) activity increased after most exposure treatments while pyrogallol (PPX) and ascorbate peroxidase (APX) activities were not changed. Exceptions were reduced PPX and APX activity after longer exposure at 23 V m(-1) and increased PPX activity after exposures at 10 and 120 V m(-1). By contrast, at 900 MHz almost all exposure treatments significantly increased level of lipid peroxidation and H(2)O(2) content but mostly decreased PPX activity and did not affect CAT activity. Exceptions were exposures to a modulated field and to the field of 120 V m(-1) which increased PPX and CAT activity. At this frequency APX activity was significantly decreased after exposure at 10 V m(-1) and longer exposure at 23 V m(-1) but it increased after a shorter exposure at 23 V m(-1). At both frequencies no differences in isoenzyme patterns of antioxidative enzymes or HSP70 level were found between control and exposed plants. Our results showed that non-thermal exposure to investigated radiofrequency fields induced oxidative stress in duckweed as well as unspecific stress responses, especially of antioxidative enzymes. However, the observed effects markedly depended on the field frequencies applied as well as on other exposure parameters (strength, modulation and exposure time). Enhanced lipid peroxidation and H(2)O(2) content accompanied by diminished antioxidative enzymes activity caused by exposure to investigated EMFs, especially at 900 MHz, indicate that oxidative stress could partly be due to changed activities of antioxidative enzymes.
The effect of low-intensity electromagnetic microwave field on seed germination
- L Ponomarev
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An Internet resource for the calculation of the dielectric properties of body tissues in the frequency range 10Hz-100GHz
- D Andreuccetti
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of the dielectric properties of body tissues in the frequency range
Effect of mobile phone radiation on antioxidant machinery in roots of onion (Allium cepa)
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- Ç Atak
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The effect of low-intensity electromagnetic microwave field on seed germination
- Ponomarev