Low frequency magnetic field assisted production of acidic protease by Aspergillus niger.

Acid protease is widely used in industries such as food processing and feed additives. In the study, low frequency magnetic field (LF-MF) as an aid enhances acid protease production by Aspergillus niger (A. niger). The study assessed mycelial biomass, the enzymic activity of the acidic protease and underlying mechanism. At low intensities, alternating magnetic field (AMF) is more effective than static magnetic fields (SMF). Under optimal magnetic field conditions, acid protease activity and biomass increased by 91.44% and 16.31%, as compared with the control, respectively. Maximum 19.87% increase in enzyme activity after magnetic field treatment of crude enzyme solution in control group. Transcriptomics analyses showed that low frequency alternating magnetic field (LF-AMF) treatment significantly upregulated genes related to hydrolases and cell growth. Our results showed that low-frequency magnetic fields can enhance the acid protease production ability of A. niger, and the effect of AMF is better at low intensities. The results revealed that the effect of magnetic field on the metabolic mechanism of A. niger and provided a reference for magnetic field-assisted fermentation of A. niger.

Effects of low-frequency magnetic field on solubility, structural and functional properties of soy 11S globulin.

BACKGROUND: Soy 11S globulin has high thermal stability, limiting its application in the production of low-temperature gel foods. In this study, the low-frequency magnetic field (LF-MF, 5 mT) treatment (time, 30, 60, 90, and 120 min) was used to improve the solubility, conformation, physicochemical properties, surface characteristics, and gel properties of soy 11S globulin. RESULTS: Compared with the native soy 11S globulin, the sulfhydryl content, emulsifying capacity, gel strength, water-holding capacity, and absolute zeta potential values significantly increased (P < 0.05) after LF-MF treatment. The LF-MF treatment induced the unfolding of the protein structure and the fracture of disulfide bonds. The variations in solubility, foaming properties, viscosity, surface hydrophobicity, and rheological properties were closely related to the conformational changes of soy 11S globulin, with the optimum LF-MF modification time being 90 min. CONCLUSION: LF-MF treatment is an effective method to improve various functional properties of native soy 11S globulin, and this study provides a reference for the development of plant-based proteins in the food industry. © 2024 Society of Chemical Industry.

[Possibilities for increasing the effectiveness of treatment of respiratory infections of the upper respiratory tract in children of various age groups]. / Vozmozhnosti povysheniya effektivnosti terapii respiratornykh infektsii verkhnikh dykhatel'nykh putei u detei razlichnykh vozrastnykh grupp.

The article discusses the experience of complex therapy of rhinitis and sinusitis in children of various age groups, confirming the effectiveness of the combined effects of local thermotherapy, pulsed red light and low-frequency magnetic field. This combination of physical factors has an anti-inflammatory, decongestant, stimulating local cellular activity effect and helps to increase the effectiveness and reduce the overall treatment time for these diseases. The purpose of the study is to evaluate the effectiveness of the combined use of heat, red spectrum phototherapy and magnetic field in the treatment of children with rhinitis and sinusitis. Materials and methods. The observation included 30 children with rhinitis and 40 children with sinusitis aged 2-18 years, receiving combined physiotherapy procedures as part of the main treatment. Results and its discussion. The positive effect of the combined effects of thermotherapy, pulsed light radiation in the red range and low-frequency magnetic field on clinical symptoms and functional indicators of nasal breathing in children with rhinitis and sinusitis has been confirmed. Conclusions. The use of a course of procedures combined with the effects of local thermotherapy, pulsed red light and low-frequency magnetic field against the background of the main treatment helps to increase the effectiveness of the treatment of respiratory infections of the upper respiratory tract in children of various age groups.

A 50 Hz magnetic field influences the viability of breast cancer cells 96 h after exposure.

BACKGROUND: The exposure of breast cancer to extremely low frequency magnetic fields (ELF-MFs) results in various biological responses. Some studies have suggested a possible cancer-enhancing effect, while others showed a possible therapeutic role. This study investigated the effects of in vitro exposure to 50 Hz ELF-MF for up to 24 h on the viability and cellular response of MDA-MB-231 and MCF-7 breast cancer cell lines and MCF-10A breast cell line. METHODS AND RESULTS: The breast cell lines were exposed to 50 Hz ELF-MF at flux densities of 0.1 mT and 1.0 mT and were examined 96 h after the beginning of ELF-MF exposure. The duration of 50 Hz ELF-MF exposure influenced the cell viability and proliferation of both the tumor and nontumorigenic breast cell lines. In particular, short-term exposure (4-8 h, 0.1 mT and 1.0 mT) led to an increase in viability in breast cancer cells, while long and high exposure (24 h, 1.0 mT) led to a decrease in viability and proliferation in all cell lines. Cancer and normal breast cells exhibited different responses to ELF-MF. Mitochondrial membrane potential and reactive oxygen species (ROS) production were altered after ELF-MF exposure, suggesting that the mitochondria are a probable target of ELF-MF in breast cells. CONCLUSIONS: The viability of breast cells in vitro is influenced by ELF-MF exposure at magnetic flux densities compatible with the limits for the general population and for workplace exposures. The effects are apparent after 96 h and are related to the ELF-MF exposure time.

Estimation of the general population and children under five years of age in France exposed to magnetic field from high or very high voltage power line using geographic information system and extrapolated field data.

BACKGROUND: The effects of extremely low-frequency magnetic fields, especially their long-term health effects, including childhood leukaemia, remain elusive. The International Agency for Research on Cancer has classified the exposure to magnetic fields >0.4 µT as 'possibly carcinogenic to humans (group 2 B)' for childhood leukaemia. However, the number of exposed individuals, particularly children, remains poorly documented in international literature. The objective of this study was to estimate the number of individuals living near a high or very high voltage line in France (≥63 kV), among the general population and children under the age of five years. METHODS: The estimate considered different exposure scenarios depending on the line voltage and the distance of the housing from it, and whether the line is overhead or underground. The exposure scenarios were obtained using a multilevel linear model created from a measurement database published by "Réseau de transport d'électricité", the operator of the French electricity transmission network. RESULTS: Between 0.11% (n = 67,893) and 1.01% (n = 647,569) of the French population and between 0.10% (n = 4712) and 1.03% (n = 46,950) of children under five years of age were estimated to be living in an area potentially exposed to a magnetic field, depending on the exposure scenario (>0.4 µT and >0.1 µT, respectively). CONCLUSIONS: By making it possible to estimate the total number of residents, schools, and health institutions near high-voltage power lines, the proposed methodology can help identify potential co-exposures near high-voltage power lines, which are regularly cited as a possible explanation for contradictory results from epidemiological studies.

Real-Time Observation and Analysis of Magnetomechanical Actuation of Magnetic Nanoparticles in Cells.

The origin of cell death in the magnetomechanical actuation of cells induced by magnetic nanoparticle motion under low-frequency magnetic fields is still elusive. Here, a miniaturized electromagnet fitted under a confocal microscope is used to observe in real time cells specifically targeted by superparamagnetic nanoparticles and exposed to a low-frequency rotating magnetic field. Our analysis reveals that the lysosome membrane is permeabilized in only a few minutes after the start of magnetic field application, concomitant with lysosome movements toward the nucleus. Those events are associated with disorganization of the tubulin microtubule network and a change in cell morphology. This miniaturized electromagnet will allow a deeper insight into the physical, molecular, and biological process occurring during the magnetomechanical actuation of magnetic nanoparticles.

Adhesion of Escherichia coli and Lactobacillus fermentum to Films and Electrospun Fibrous Scaffolds from Composites of Poly(3-hydroxybutyrate) with Magnetic Nanoparticles in a Low-Frequency Magnetic Field.

The ability of materials to adhere bacteria on their surface is one of the most important aspects of their development and application in bioengineering. In this work, the effect of the properties of films and electrospun scaffolds made of composite materials based on biosynthetic poly(3-hydroxybutyrate) (PHB) with the addition of magnetite nanoparticles (MNP) and their complex with graphene oxide (MNP/GO) on the adhesion of E. coli and L. fermentum under the influence of a low-frequency magnetic field and without it was investigated. The physicochemical properties (crystallinity; surface hydrophilicity) of the materials were investigated by X-ray structural analysis, differential scanning calorimetry and "drop deposition" methods, and their surface topography was studied by scanning electron and atomic force microscopy. Crystal violet staining made it possible to reveal differences in the surface charge value and to study the adhesion of bacteria to it. It was shown that the differences in physicochemical properties of materials and the manifestation of magnetoactive properties of materials have a multidirectional effect on the adhesion of model microorganisms. Compared to pure PHB, the adhesion of E. coli to PHB-MNP/GO, and for L. fermentum to both composite materials, was higher. In the magnetic field, the adhesion of E. coli increased markedly compared to PHB-MNP/GO, whereas the effect on the adhesion of L. fermentum was reversed and was only evident in samples with PHB-MNP. Thus, the resultant factors enhancing and impairing the substrate binding of Gram-negative E. coli and Gram-positive L. fermentum turned out to be multidirectional, as they probably have different sensitivity to them. The results obtained will allow for the development of materials with externally controlled adhesion of bacteria to them for biotechnology and medicine.

Extremely low frequency magnetic field enhances expression of a specific recombinant protein in bacterial host.

Expression of proteins in bacterial host cells, particularly E.coli, has gained much attention in recent years. Low expression outcome is the main technical drawback associated with this procedure, further restricting its largescale application in industry. Therefore, application of new amendments or reformations are required before further proceedings. Extremely low frequency magnetic fields (ELF-MFs) have shown to significantly affect biological processes, including gene expression, in E.coli. In current study, we investigated whether application of ELF-MF could result in overexpression of proteins in E.coli or not. Cluster of differentiation-22 (CD22), as a model protein, was expressed in E.Coli Rosetta (DE3) under continuous exposure to ELF-MF after applying various concentrations of Isopropyl ß-d-1-thiogalactopyranoside (IPTG) (0.25-1.25 mM) as inducer. The strength and frequency of electromagnetic fields (EMFs) ranged between 15 and 100 mT and 2.5-20 Hz respectively. Interestingly, application of 55 mT EMFs with frequencies ranging from 2.5 to 2.8 Hz significantly enhanced the yield of expression at all studied IPTG concentrations. Contrarily, EMFs with intensities other than 55 mT meaningfully declined protein expression at IPTG concentrations equal to 1 and 1.25 mM. In conclusion, application of specific range of ELF-MFs may be exploited as a new modification for enhancing heterologous expression of proteins in E.coli.

Influence of Calcium Resonance-Tuned Low-Frequency Magnetic Fields on Daphnia magna.

A biophysical model for calculating the effective parameters of low-frequency magnetic fields was developed by Lednev based on summarized empirical data. According to this model, calcium ions as enzyme cofactors can be the primary target of low-frequency magnetic fields with different parameters tuned to calcium resonance. However, the effects of calcium-resonant combinations of static and alternating magnetic fields that correspond to Lednev's model and differ by order in frequency and intensity were not studied. It does not allow for confidently discussing the primary targets of low-frequency magnetic fields in terms of the magnetic influence on ions-enzyme cofactors. To clarify this issue, we examined the response of freshwater crustaceans Daphnia magna to the impact of combinations of magnetic fields targeted to calcium ions in enzymes according to Lednev's model that differ in order of magnitude. Life-history traits and biochemical parameters were evaluated. Exposure of daphnids to both combinations of magnetic fields led to a long-term delay of the first brood release, an increase in the brood size, a decrease in the number of broods, and the period between broods. The amylolytic activity, proteolytic activity, and sucrase activity significantly decreased in whole-body homogenates of crustaceans in response to both combinations of magnetic fields. The similarity in the sets of revealed effects assumes that different magnetic fields tuned to calcium ions in biomolecules can affect the same primary molecular target. The results suggest that the low-frequency magnetic fields with parameters corresponding to Lednev's model of interaction between biological molecules and ions can remain effective with a significant decrease in the static magnetic background.

Exposure to 60 Hz magnetic field can affect membrane proteins and membrane potential in human cancer cells.

The experimental data support the hypothesis that extremely low frequency magnetic field (ELF-MF) can affect cell membranes. Since our previous studies suggested that MF changes the permeability of cell membrane, in this study we focused on the cell membrane and investigated the effect of 60 Hz, 50 mT MF on the membrane potential and membrane proteins. The membrane potentials of three cultured human cancer cell lines, A549, MES-SA, and MES-SA/Dx5, were increased by exposure to ELF-MF. When exposed to MF and an anticancer drug, changes in the membrane potentials were detected in A549 and MES-SA cells, but not in the multi drug-resistant cells, MES-SA/Dx5. We examined whether MF has an influence on the membrane proteins extracted from cultured A549 cells, using DiBAC4(3) dye enhanced fluorescence binding to a hydrophobic site. The increase in fluorescence observed following MF exposure for 10 min indicated that the structure of the hydrophobic site on the membrane proteins changed and became more likely to bind the probe dye. A decrease in fluorescence was detected following exposure to MF for 240 min. These results indicated that 60 Hz, 50 mT MF causes changes in the membrane potential of cultured cancer cells and the conformation of membrane proteins extracted from cultured cancer cells, and has different effects depending on the exposure time.

Low-Frequency Magnetic Field of Appropriate Strengths Changed Secondary Metabolite Production and Na+ Concentration of Intracellular and Extracellular Monascus purpureus.

Monascus purpureus is used to yield edible pigments accompanied by mycotoxin-citrinin. A low-frequency (<300 Hz) magnetic field (LF-MF) affects microbial metabolism. The link of LF-MF with secondary metabolites and intracellular and extracellular Na+ levels in M. purpureus was determined. The fermentation broth was exposed to LF-MF during the first 2 days of fermentation and continuously cultured at 30°C and 200 rpm until the 8th day of fermentation. Results showed that LF-MF treatments didn't affect the growth of M. purpureus in liquid-state fermentation. Compared with the control, citrinin production showed a decrease of 45.0%, while yellow, red, and orange pigment production showed an increase of 72.9, 73.9, and 40.1%, respectively, with LF-MF treatment of 1.6 mT. This was in agreement with downregulation of pksCT and ctnA, and upregulation of pksPT, pigR, veA, and laeA at the transcriptional level. Moreover, 1.6 mT LF-MF exposure caused the transfer of Na+ from extracellular to intracellular, which was validated through the upregulation of transmembrane sensor synthesis genes and the changes in the relative expression levels of the P-type ATPase and protein phosphatase genes. This study established that LF-MF could inhibit citrinin and stimulate pigment production and change intracellular and extracellular Na+ concentrations. Bioelectromagnetics. 2020;41:289-297 © 2020 Bioelectromagnetics Society.

Effect of low frequency magnetic field on efficiency of chromosome break repair.

DNA repair is essential to maintain genome integrity. There is scientific evidence that exposure to magnetic fields (MF) can produce alterations in DNA repair without clear conclusions. This work aims to study the cellular response to and repair of a very deleterious type of DNA damage, the DNA double strand break (DSB), in S. cerevisiae, under MF exposure. In S. cerevisiae cells, pairs of DSB were induced enzymatically by HO endonuclease by plating the cells on Galactose-containing media. The repair processes took place under exposure to a 50Hz, 2.45mT sinusoidal MF during 21 days. MF was generated by a pair of Helmholtz coils. MF induced 1.29- and 1.5-fold increase in the number of colonies grown at day 21 of exposure in relation to untreated controls for Pho91 and Rmd5 strain, respectively. In relation to the kinetics of DSB repair during MF exposure, a higher increase (55.56-fold) in DNA reparation was observed at day 15 for Rmd5 strain in relation to the slight increment (1.18-fold) found for Pho91 strain. The results suggest that long-term MF exposure could increase the DNA repair activity and there may be a relationship between the position of the DSB and the distance to the centromere.

Amending the Efficiency of Antimicrobials against Multidrug-Resistant Pseudomonas aeruginosa by Low-Frequency Magnetic Fields.

We studied the effect of 1- and 2-h exposure to low-frequency magnetic fields (0.3 and 0.42 mT) on the sensitivity of Pseudomonas aeruginosa to 18 antibiotics. P. aeruginosa samples were obtained from 20 patients with burns. Exposure to magnetic field reduced the resistance of P. aeruginosa and increased their susceptibility to antimicrobial drugs. This increase was positively correlated with field intensity and duration of exposure. After 2-h exposure to 0.42 mT, susceptibility of P. aeruginosa to antimicrobial drugs aztreonam, ceftazidime, colistin, imipenem, levofloxacin, and meropenem significantly increased. In addition, resensitization of P. aeruginosa to carbapenems, penicillin, quinolones, and aminoglycosides groups was observed.

Extremely low frequency magnetic field induces human neuronal differentiation through NMDA receptor activation.

Magnetic fields with different frequency and intensity parameters exhibit a wide range of effects on different biological models. Extremely low frequency magnetic field (ELF MF) exposure is known to augment or even initiate neuronal differentiation in several in vitro and in vivo models. This effect holds potential for clinical translation into treatment of neurodegenerative conditions such as autism, Parkinson's disease and dementia by promoting neurogenesis, non-invasively. However, the lack of information on underlying mechanisms hinders further investigation into this phenomenon. Here, we examine involvement of glutamatergic Ca2+ channel, N-methyl-D-aspartate (NMDA) receptors in the process of human neuronal differentiation under ELF MF exposure. We show that human neural progenitor cells (hNPCs) differentiate more efficiently under ELF MF exposure in vitro, as demonstrated by the abundance of neuronal markers. Furthermore, they exhibit higher intracellular Ca2+ levels as evidenced by c-fos expression and more elongated mature neurites. We were able to neutralize these effects by blocking NMDA receptors with memantine. As a result, we hypothesize that the effects of ELF MF exposure on neuronal differentiation originate from the effects on NMDA receptors, which sequentially triggers Ca2+-dependent cascades that lead to differentiation. Our findings identify NMDA receptors as a new key player in this field that will aid further research in the pursuit of effect mechanisms of ELF MFs.

Magnetic nanorods for remote disruption of lipid membranes by non-heating low frequency magnetic field.

This work presents direct evidence of disordering of liposomal membranes by magnetic nanoparticles during their exposures to non-heating alternating Extremely Low Frequency Magnetic Field (ELF MF). Changes in the lipid membrane structure were demonstrated by the Attenuated total reflection Fourier Transform Infrared and fluorescence spectroscopy. Specifically, about 50% of hydrophobic chains became highly mobile under the action of ELF MF. Magnetic field-induced increase in the membrane fluidity was accompanied by an increase in membrane permeability and release of solutes entrapped in liposomes. The effect of ELF MF on the membrane fluidity was greater in case of 70 × 12 nm magnetite nanorods adsorbed on the liposomes surface compared to liposomes with ~7 nm spherical MNPs embedded within lipid membranes. A physical model of this process explaining experimental data is suggested. The obtained results open new horizons for the development of systems for triggered drug release without dangerous heating and overheating of tissues.

Influence of extremely low frequency magnetic fields on Ca2+ signaling and double messenger system in mice hippocampus and reversal function of procyanidins extracted from lotus seedpod.

This research investigated the influence of extremely low frequency magnetic fields (ELF-MF; 50 Hz, 8 mT, 4 h per day, for 28 days) on calcium ion signaling and the double messenger system in the hippocampus of mice. Messengers that were studied included: G-protein, Ins(1,4,5)P3 (IP3 ), diacylglycerol (DAG), cAMP-dependent protein kinase (PKA), and Ca2+ -dependent protein kinase C (PKC). The results showed that ELF-MF caused an increase in the levels of Gi protein, IP3, DAG, PKA and PKC beta, calcium and calmodulin-dependent protein phosphatase calcineuring (PP2B), and intracellular Ca2+ content, and a decrease in calcium/calmodulin-dependent protein kinase II (CaMK II) and PKC alpha. In addition, ELF-MF exposure decreased the level of brain-derived neurotrophic factor (BDNF), which played a key role in hippocampal neuronal cell death. However, oral administration of procyanidins from lotus seedpod (LSPCs) (especially 90 mg kg-1 ) significantly recovered these changes, and nearly reached normal levels. All these showed that LSPCs may mediate calcium signal and double messenger system through Ca2+ /CaMK II/CREB/BDNF and DG/PKC/MAPK signaling pathways to reverse the alteration caused by ELF-MF. Bioelectromagnetics. 38:436-446, 2017. © 2017 Wiley Periodicals, Inc.

Assessing the combined effect of extremely low-frequency magnetic field exposure and oxidative stress on LINE-1 promoter methylation in human neural cells.

Extremely low frequency magnetic fields (ELF-MF) have been classified as "possibly carcinogenic", but their genotoxic effects are still unclear. Recent findings indicate that epigenetic mechanisms contribute to the genome dysfunction and it is well known that they are affected by environmental factors. To our knowledge, to date the question of whether exposure to ELF-MF can influence epigenetic modifications has been poorly addressed. In this paper, we investigated whether exposure to ELF-MF alone and in combination with oxidative stress (OS) can affect DNA methylation, which is one of the most often studied epigenetic modification. To this end, we analyzed the DNA methylation levels of the 5'untranslated region (5'UTR) of long interspersed nuclear element-1s (LINE-1 or L1), which are commonly used to evaluate the global genome methylation level. Human neural cells (BE(2)C) were exposed for 24 and 48 h to extremely low frequency pulsed magnetic field (PMF; 50 Hz, 1 mT) in combination with OS. The methylation levels of CpGs located in L1 5'UTR region were measured by MassARRAY EpiTYPER. The results indicate that exposures to the single agents PMF and OS induced weak decreases and increases of DNA methylation levels at different CpGs. However, the combined exposure to PMF and OS lead to significant decrease of DNA methylation levels at different CpG sites. Most of the changes were transient, suggesting that cells can restore homeostatic DNA methylation patterns. The results are discussed and future research directions outlined.

Extremely low frequency magnetic field protects injured spinal cord from the microglia- and iron-induced tissue damage.

Spinal cord injury (SCI) is insult to the spinal cord, which results in loss of sensory and motor function below the level of injury. SCI results in both immediate mechanical damage and secondary tissue degeneration. Following traumatic insult, activated microglia release proinflammatory cytokines and excess iron due to hemorrhage, initiating oxidative stress that contributes to secondary degeneration. Literature suggests that benefits are visible with the reduction in concentration of iron and activated microglia in SCI. Magnetic field attenuates oxidative stress and promotes axonal regeneration in vitro and in vivo. The present study demonstrates the potential of extremely low frequency magnetic field to attenuate microglia- and iron-induced secondary injury in SCI rats. Complete transection of the spinal cord (T13 level) was performed in male Wistar rats and subsequently exposed to magnetic field (50 Hz,17.96 µT) for 2 h daily for 8 weeks. At the end of the study period, spinal cords were dissected to quantify microglia, macrophage, iron content and study the architecture of lesion site. A significant improvement in locomotion was observed in rats of the SCI + MF group as compared to those in the SCI group. Histology, immunohistochemistry and flow cytometry revealed significant reduction in lesion volume, microglia, macrophage, collagen tissue and iron content, whereas, a significantly higher vascular endothelial growth factor expression around the epicenter of the lesion in SCI + MF group as compared to SCI group. These novel findings suggest that exposure to ELF-MF reduces lesion volume, inflammation and iron content in addition to facilitation of angiogenesis following SCI.

[The specific features of the development of metabolic and regenerative processes under the action of low-intensity electromagnetic radiation in radiation exposure conditions (an experimental study)]. / Osobennosti razvitiia metabolicheskikh i regenerativnykh protsessov pri deistvii nizkointensivnykh élektromagnitnykh izluchenii v usloviiakh radiatsionnogo oblucheniia (éksperimental'noe issledovanie).

The experiments on male white rats with the use of biochemical, photo-optical, and electron-microscopic techniques have demonstrated that the use of low-intensity electromagnetic radiation of ultrahigh frequency (EMR UHF) and low-intensity low-frequency magnetic field (MF) during the post-irradiation period (within 21 days after exposure to radiation) enhanced the metabolic and regenerative processes in the testes and liver. It was shown that the application of MF largely intensified the antioxidant activity whereas EMR UHF preferentially stimulated the biosynthetic processes as well as the processes of cellular and intracellular regeneration.

Acid sphingomyelinase mediates 50-Hz magnetic field-induced EGF receptor clustering on lipid raft.

Previously, we found that exposure to a 50-Hz magnetic field (MF) could induce epidermal growth factor receptor (EGFR) clustering and phosphorylation on cell surface. In order to explore the possible mechanisms, the roles of acid sphingomyelinase (ASMase) and lipid raft in MF-induced EGFR clustering were investigated in the present study. Human amnion epithelial (FL) cells were exposed to a 50-Hz MF at 0.4 mT for different durations. Intracellular ASMase activity was detected using the Amplex® Red Sphingomyelinase Assay Kit. EGFR clustering, ASMase, and lipid rafts on cell membrane were analyzed using confocal microscopy after indirect immunofluorescence staining. Results showed that disturbing lipid rafts with nystatin could inhibit MF-induced EGFR clustering, indicating that it was dependent on intact lipid raft. Exposure of FL cells to MF significantly enhanced ASMase activity and induced ASMase translocation to membrane that co-localized with lipid rafts. Treatment with imipramine, an ASMase inhibitor, inhibited the MF-induced EGFR clustering. This inhibitory effect could be blocked by the addition of C2-ceramide in the culture medium. It suggested that ASMase mediated the 50-Hz MF-induced EGFR clustering via ceramide which was produced from hydrolyzation on lipid rafts.