Effect of Humid Air Exposed to IR Radiation on Enzyme Activity.

Water vapor absorbs well in the infra-red region of the electromagnetic spectrum. Absorption of radiant energy by water or water droplets leads to formation of exclusion zone water that possesses peculiar physico-chemical properties. In the course of this study, normally functioning and damaged alkaline phosphatase, horseradish peroxidase and catalase were treated with humid air irradiated with infrared light with a wavelength in the range of 1270 nm and referred to as coherent humidity (CoHu). One-minute long treatment with CoHu helped to partially protect enzymes from heat inactivation, mixed function oxidation, and loss of activity due to partial unfolding. Authors suggest that a possible mechanism underlying the observed effects involves altering the physicochemical properties of aqueous media while treatment of the objects with CoHu where CoHu acts as an intermediary.

60Co-γ Radiation Alters Developmental Stages of Zeugodacus cucurbitae (Diptera: Tephritidae) Through Apoptosis Pathways Gene Expression.

Radiation is considered as a promising insect pest control strategy for minimizing postharvest yield losses. Among various techniques, irradiation is a method of choice as it induces lethal biochemical or molecular changes that cause a downstream cascade of abrupt physiological abnormalities at the cellular level. In this study, we evaluated the effect of 60Co-γ radiation on various developmental stages of Zeugodacus cucurbitae Coquillett and subsequent carry-over effects on the progeny. For this purpose, we treated eggs with 30- and 50-Gy radiation doses of 60Co-γ. We found that radiation significantly affected cellular antioxidants, insect morphology, and gene expression profiles. Our results indicate that in response to various doses of irradiation reactive oxygen species, catalase, peroxidase, and superoxide dismutase activities were increased along with a significant increase in the malondialdehyde (MDA) content. We observed higher mortality rates during the pupal stage of the insects that hatched from irradiated eggs (50 Gy). Furthermore, the life span of the adults was reduced in response to 50 Gy radiation. The negative effects carried over to the next generation were marked by significantly lower fecundity in the F1 generation of the irradiation groups as compared to control. The radiation induced morphological abnormalities at the pupal, as well as the adult, stages. Furthermore, variations in the gene expression following irradiation are discussed. Taken together, our results signify the utility of 60Co-γ radiation for fruit fly postharvest management.

Molecular and Biochemical Basis of Fluoroquinolones-Induced Phototoxicity-The Study of Antioxidant System in Human Melanocytes Exposed to UV-A Radiation.

Phototoxicity of fluoroquinolones is connected with oxidative stress induction. Lomefloxacin (8-halogenated derivative) is considered the most phototoxic fluoroquinolone and moxifloxacin (8-methoxy derivative) the least. Melanin pigment may protect cells from oxidative damage. On the other hand, fluoroquinolone-melanin binding may lead to accumulation of drugs and increase their toxicity to skin. The study aimed to examine the antioxidant defense system status in normal melanocytes treated with lomefloxacin and moxifloxacin and exposed to UV-A radiation. The obtained results demonstrated that UV-A radiation enhanced only the lomefloxacin-induced cytotoxic effect in tested cells. It was found that fluoroquinolones alone and with UV-A radiation decreased superoxide dismutase (SOD) activity and SOD1 expression. UV-A radiation enhanced the impact of moxifloxacin on hydrogen peroxide-scavenging enzymes. In turn, lomefloxacin alone increased the activity and the expression of catalase (CAT) and glutathione peroxidase (GPx), whereas UV-A radiation significantly modified the effects of drugs on these enzymes. Taken together, both analyzed fluoroquinolones induced oxidative stress in melanocytes, however, the molecular and biochemical studies indicated the miscellaneous mechanisms for the tested drugs. The variability in phototoxic potential between lomefloxacin and moxifloxacin may result from different effects on the antioxidant enzymes.

High-speed, inline measurement of protein activity and inactivation processes by supercontinuum attenuation spectroscopy.

Some proteins such as catalase and glutamate dehydrogenase (GDH) are very sensitive to external factors such as irradiation or heat, which may cause inactivation. Since proteins are used in a wide field of applications, the entire activity has to be ensured during the whole process. By default, activity is measured by invasive and offline activity assays. To avoid the need for a time-consuming offline analysis, we developed an optical high-speed measurement technique, which may form the basis for the non-invasive inline control of enzyme processes e.g. in the textile or food industry. The technique is based on attenuation spectroscopy using a supercontinuum laser source in combination with multivariate data analysis, in particular partial least squares regression (PLSR). For verification of the approach, samples treated by various stresses were analyzed in parallel by activity assays and our new method. Applying this technique, we were able to determine the activity in the turbid catalase samples after heat treatment, addition of guanidine-HCl or irradiation with UV light by applying partial least squares regression. Furthermore, we demonstrate that the combination of broadband attenuation spectroscopy and PLSR enables us to determine also the activity of GDH in clear solutions after heat treatment.

Effect of ultrasonic field on the enzyme activities and ion balance of potential pathogen Saccharomyces cerevisiae.

OBJECTIVES: This study aimed at investigating the enzyme activities and ion concentrations in potential pathogen S.cerevisiae upon ultrasonic treatment. METHODS: The activities of ATPase and antioxidase were identified by ATPase, SOD, and CAT assay kits following the instructions. Extracellular Ca2+ and K+ concentrations were determined in an atomic absorption spectrometer with calcium and potassium hollow-cathode lamps as radiation sources. RESULTS: SOD and CAT activities were enhanced by relatively low ultrasonic power at early time points and reduced to lower levels. Total ATPase, Na+/K+-ATPase, and Ca2+/Mg2+-ATPase activities were reduced by ultrasonic field, with higher reducing rate at stronger ultrasonic power and early time points. In addition, ultrasonic field disturbed the Ca2+ and K+ balances in S.cerevisiae cells. CONCLUSIONS: Ultrasonic field resulted in the reduce even the lost of S.cerevisiae cell viability.

The effect of melatonin on the liver of rats exposed to microwave radiation.

OBJECTIVES: We aimed to clarify if melatonin treatment (2 mg/kg i.p.) may favorably impact the liver tissue in rats exposed to microwave radiation. The experiment was performed on 84 six-weeks-old Wistar male rats exposed for 4h a day, for 20, 40 and 60 days, respectively, to microwaves (900 MHz, 100-300 microT, 54-160 V/m). Rats were divided in to four groups: I (control) - rats treated with saline, II (Mel) - rats treated with melatonin, III (MWs) - microwave exposed rats, IV (MWs + Mel) - MWs exposed rats treated with melatonin. We evaluated oxidative stress parameters (malondialdehyde and carbonyl group content), catalase, xanthine oxidase, deoxyribonuclease I and II activity. BACKGROUND: Oxidative stress is the key mechanism of the microwave induced tissue injury. Melatonin, a lipophilic indoleamine primarily synthesized and released from the pineal gland is a powerful antioxidant. RESULTS: Exposure to microwaves caused an increase in malondialdehyde after 40 (p < 0.01), protein carbonyl content after 20 (p < 0.05), catalase (p < 0.05) and xantine oxidase activity (p < 0.05) after 40 days. Increase in deoxyribonuclease I activity was observed after 60 days (p < 0.05), while deoxyribonuclease II activity was unaffected. Melatonin treatment led to malondialdehyde decrease after 40 days (p< 0.05), but surprisingly had no effect on other analyzed parameters. CONCLUSION: Melatonin exerts certain antioxidant effects in the liver of rats exposed to microwaves, by diminishing the intensity of lipid peroxidation(Fig. 6, Ref. 32).

Effects of extremely low frequency electromagnetic field (ELF-EMF) on catalase, cytochrome P450 and nitric oxide synthase in erythro-leukemic cells.

AIMS: Extremely low frequency electromagnetic fields (ELF-EMFs) are widely employed in electrical appliances and different equipment such as television sets, mobile phones, computers and microwaves. The molecular mechanism through which ELF-EMFs can influence cellular behavior is still unclear. A hypothesis is that ELF-EMFs could interfere with chemical reactions involving free radical production. Under physiologic conditions, cells maintain redox balance through production of ROS/RNS and antioxidant molecules. The altered balance between ROS generation and elimination plays a critical role in a variety of pathologic conditions including neurodegenerative diseases, aging and cancer. Actually, there is a disagreement as to whether there is a causal or coincidental relationship between ELF-EMF exposure and leukemia development. Increased ROS levels have been observed in several hematopoietic malignancies including acute and chronic myeloid leukemias. MAIN METHODS: In our study, the effect of ELF-EMF exposure on catalase, cytochrome P450 and inducible nitric oxide synthase activity and their expression by Western blot analysis in myelogenous leukemia cell line K562 was evaluated. KEY FINDINGS: A significant modulation of iNOS, CAT and Cyt P450 protein expression was recorded as a result of ELF-EMF exposure in both phorbol 12-myristate 13-acetate (PMA)-stimulated and non-stimulated cell lines. Modulation in kinetic parameters of CAT, CYP-450 and iNOS enzymes in response to ELF-EMF indicates an interaction between the ELF-EMF and the enzymological system. SIGNIFICANCE: These new insights might be important in establishing a mechanistic framework at the molecular level within which the possible effects of ELF-EMF on health can be understood.

[Study of the influence of low-dose γ-irradiation on the functional state of peripheral blood erythrocytes of rats].

Low-intensity radiation at the absorbed dose of 4 µGy/min is a stressor of medium strength. In male Wistar rats, a pronounced and long-lasting response occurs in the system of red blood cells at the accumulated dose of 4.8 mGy. Functional deficiency of circulating cells was evaluated by the resistance of erythrocytes to acid lyse and the activity of the main antioxidant enzymes--superoxide dismutase (SOD) and catalase (CAT). The minimum "threshold" doses of radiation that cause systemic reactions occur in the range of units of miligrey.

[The antioxidant enzyme activity in mouse liver mitochondria after nanosecond pulsed periodic X-ray exposure].

The effect of repetitive pulsed X-ray (4 ns pulse duration, 300 kV accelerating voltage; 2.5 kA electron beam current) on the antioxidant enzyme activity in mouse liver mitochondria has been investigated. The mitochondrial suspension was exposed to single 4000 pulse X-ray radiation with repetition rates ranging between 10 and 22 pps (pulsed dose was 0.3-1.8 x 10(-6) Gy/pulse, the total absorbed dose following a single exposure was 7.2 x 10(-3) Gy). It was shown that a short-time exposure to X-ray radiation changes the antioxidant enzyme activity in mouse liver mitochondria. The greatest effect was observed in the changes of the activity of the metal-containing enzymes: superoxide dismutase and glutathione peroxidase. The effect depends on the pulse repetition frequency and radiation dose.

Activation of de novo GSH synthesis pathway in mouse spleen after long term low-dose γ-ray irradiation.

Glutathione (GSH) is an important cellular antioxidant and has a critical role in maintaining the balance of cellular redox. In this study, we investigated the GSH biosynthesis genes involved in the elevation of endogenous GSH levels using an irradiation system with an irradiation dose rate of 1.78 mGy/h, which was about 40,000 times less than the dose rates used in other studies. The results showed that GSH levels were significantly increased in the low-dose (0.02 and 0.2 Gy) irradiated group compared to those in the non-irradiated group, but enzymatic antioxidants such as superoxide dismutase and catalase were not induced at any doses tested. The elevation in GSH was accompanied by elevated expression of glutamate-cysteine ligase modifier subunit, but no changes were observed in the expression of glutamate-cysteine ligase catalytic subunit and thioredoxin in de novo GSH synthesis. In the case of genes involved in the GSH regeneration cycle, the expression of glutathione reductase was not changed after irradiation, whereas glutathione peroxidase was only increased in the 0.2 Gy irradiated group. Collectively, our results suggest that the de novo pathway, rather than the regeneration cycle, may be mainly switched on in response to stimulation with long-term low-dose radiation in the spleen.

Down-regulation of catalase activity allows transient accumulation of a hydrogen peroxide signal in Chlamydomonas reinhardtii.

In photosynthetic organisms, excess light is a stress that induces production of reactive oxygen species inside the chloroplasts. As a response, the capacity of antioxidative defence mechanisms increases. However, when cells of Chlamydomonas reinhardtii were shifted from dark to high light, a reversible partial inactivation of catalase activity was observed, which correlated with a transient increase in the level of H2 O2 in the 10 µm range. This concentration range seems to be necessary to activate H2 O2 -dependent signalling pathways stimulating the expression of H2 O2 responsive genes, such as the heat shock protein HSP22C. Catalase knock-down mutants had lost the transient accumulation of H2 O2 , suggesting that a decrease in catalase activity was the key element for establishing a transient H2 O2 burst. Catalase was inactivated by a one-electron event consistent with the reduction of a single cysteine. We propose that under high light intensity, the redox state of the photosynthetic electron transport chain is sensed and transmitted to the cytosol to regulate the catalase activity. This allows a transient accumulation of H2 O2 , inducing a signalling event that is transmitted to the nucleus to modulate the expression of chloroplast-directed protection enzymes.

Pre-treatment of seeds with static magnetic field ameliorates soil water stress in seedlings of maize (Zea mays L.).

The effect of magnetic field (MF) treatments of maize (Zea mays L.) var. Ganga Safed 2 seeds on the growth, leaf water status, photosynthesis and antioxidant enzyme system under soil water stress was investigated under greenhouse conditions. The seeds were exposed to static MFs of 100 and 200 mT for 2 and 1 h, respectively. The treated seeds were sown in sand beds for seven days and transplanted in pots that were maintained at -0.03, -0.2 and -0.4 MPa soil water potentials under greenhouse conditions. MF exposure of seeds significantly enhanced all growth parameters, compared to the control seedlings. The significant increase in root parameters in seedlings from magnetically-exposed seeds resulted in maintenance of better leaf water status in terms of increase in leaf water potential, turgor potential and relative water content. Photosynthesis, stomatal conductance and chlorophyll content increased in plants from treated seeds, compared to control under irrigated and mild stress condition. Leaves from plants of magnetically-treated seeds showed decreased levels of hydrogen peroxide and antioxidant defense system enzymes (peroxidases, catalase and superoxide dismutase) under moisture stress conditions, when compared with untreated controls. Mild stress of -0.2 MPa induced a stimulating effect on functional root parameters, especially in 200 mT treated seedlings which can be exploited profitably for rain fed conditions. Our results suggested that MF treatment (100 mT for 2 h and 200 for 1 h) of maize seeds enhanced the seedling growth, leaf water status, photosynthesis rate and lowered the antioxidant defense system of seedlings under soil water stress. Thus, pre sowing static magnetic field treatment of seeds can be effectively used for improving growth under water stress.

Gender bias in skin cancer: role of catalase revealed.

Sullivan et al. describe their finding that lower skin catalase activity in male as compared with female mice may be responsible for the increased skin carcinogenesis observed in UVB radiation-exposed male mice. This adds to the growing literature that points toward a gender bias in the pathogenesis of skin cancer. Delineating the events between UV exposure and carcinogenesis in relation to skin's antioxidant activity will provide insight into disease progression, prognosis, and responses to therapy. If substantiated with further studies in humans, this information may aid in designing gender-specific preventive measures aimed at reversing immune suppression through targeting the altered redox status in UV-exposed individuals.

UV light B-mediated inhibition of skin catalase activity promotes Gr-1+ CD11b+ myeloid cell expansion.

Skin cancer incidence and mortality are higher in men compared with women, but the causes of this sex discrepancy remain largely unknown. UV light exposure induces cutaneous inflammation and neutralizes cutaneous antioxidants. Gr-1(+)CD11b(+) myeloid cells are heterogeneous bone marrow-derived cells that promote inflammation-associated carcinogenesis. Reduced activity of catalase, an antioxidant present in the skin, has been associated with skin carcinogenesis. We used the outbred, immune-competent Skh-1 hairless mouse model of UVB-induced inflammation and non-melanoma skin cancer to further define sex discrepancies in UVB-induced inflammation. Our results demonstrated that male skin had relatively lower baseline catalase activity, which was inhibited following acute UVB exposure in both sexes. Further analysis revealed that skin catalase activity inversely correlated with splenic Gr-1(+)CD11b(+) myeloid cell percentage. Acute UVB exposure induced Gr-1(+)CD11b(+) myeloid cell skin infiltration, which was inhibited to a greater extent in male mice by topical catalase treatment. In chronic UVB studies, we demonstrated that the percentage of splenic Gr-1(+)CD11b(+) myeloid cells was 55% higher in male tumor-bearing mice compared with their female counterparts. Together, our findings indicate that lower skin catalase activity in male mice may at least in part contribute to increased UVB-induced generation of Gr-1(+)CD11b(+) myeloid cells and subsequent skin carcinogenesis.

900-MHz microwave radiation promotes oxidation in rat brain.

Recently, there have been several reports referring to detrimental effects due to radio frequency electromagnetic fields (RF-EMF) exposure. Special attention was given to investigate the effect of mobile phone exposure on the rat brain. Since the integrative mechanism of the entire body lies in the brain, it is suggestive to analyze its biochemical aspects. For this, 35-day old Wistar rats were exposed to a mobile phone for 2 h per day for a duration of 45 days where specific absorption rate (SAR) was 0.9 W/Kg. Animals were divided in two groups: sham exposed (n = 6) and exposed group (n = 6). Our observations indicate a significant decrease (P < 0.05) in the level of glutathione peroxidase, superoxide dismutase, and an increase in catalase activity. Moreover, protein kinase shows a significant decrease in exposed group (P < 0.05) of hippocampus and whole brain. Also, a significant decrease (P < 0.05) in the level of pineal melatonin and a significant increase (P < 0.05) in creatine kinase and caspase 3 was observed in exposed group of whole brain as compared with sham exposed. Finally, a significant increase in the level of ROS (reactive oxygen species) (P < 0.05) was also recorded. The study concludes that a reduction or an increase in antioxidative enzyme activities, protein kinase C, melatonin, caspase 3, and creatine kinase are related to overproduction of reactive oxygen species (ROS) in animals under mobile phone radiation exposure. Our findings on these biomarkers are clear indications of possible health implications.

Leaf extract of Moringa oleifera prevents ionizing radiation-induced oxidative stress in mice.

The present study evaluated the hepatoprotective effect of aqueous ethanolic Moringa oleifera leaf extract (MoLE) against radiation-induced oxidative stress, which is assessed in terms of inflammation and lipid peroxidation. Swiss albino mice were administered MoLE (300 mg/kg of body weight) for 15 consecutive days before exposing them to a single dose of 5 Gy of 6°Co γ-irradiation. Mice were sacrificed at 4 hours after irradiation. Liver was collected for immunoblotting and biochemical tests for the detection of markers of hepatic oxidative stress. Nuclear translocation of nuclear factor kappa B (NF-κB) and lipid peroxidation were augmented, whereas the superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), and ferric reducing antioxidant power (FRAP) values were decreased by radiation exposure. Translocation of NF-κB from cytoplasm to nucleus and lipid peroxidation were found to be inhibited, whereas increases in SOD, CAT, GSH, and FRAP were observed in the mice treated with MoLE prior to irradiation. Therefore pretreatment with MoLE protected against γ-radiation-induced liver damage. The protection may be attributed to the free radical scavenging activity of MoLE, through which it can ameliorate radiation-induced oxidative stress.

Modulation of NF-κB and FOXOs by baicalein attenuates the radiation-induced inflammatory process in mouse kidney.

The bioactive flavonoid baicalein has been shown to have radioprotective activity, although the molecular mechanism is poorly understood in vivo. C57BL/6 mice were irradiated with X-rays (15 Gy) with and without baicalein treatment (5 mg/kg/day). Irradiation groups showed an increase of NF-κB-mediated inflammatory factors with oxidative damage and showed inactivation of FOXO and its target genes, catalase and SOD. However, baicalein suppressed radiation-induced inflammatory response by negatively regulating NF-κB and up-regulating FOXO activation and catalase and SOD activities. Furthermore, baicalein inhibited radiation-induced phosphorylation of MAPKs and Akt, which are the upstream kinases of NF-κB and FOXOs. Based on these findings, it is concluded that baicalein has a radioprotective effect against NF-κB-mediated inflammatory response through MAPKs and the Akt pathway, which is accompanied by the protective effects on FOXO and its target genes, catalase and SOD. Thus, these findings provide new insights into the molecular mechanism underlying the radioprotective role of baicalein in mice.

[Effect of different light of LED light quality on growth and antioxidant enzyme activities of Ganoderma lucidum].

OBJECTIVE: To study the effect of light quality on growth, antioxidant enzyme activities of Ganoderma lucidum mycelium. METHOD: G. lucidum mycelium was cultured under different light qualities by light emitting diodes (LED). The growth G. lucidum mycelium was observed and antioxidant enzyme activities was determined in different growth periods. RESULT: Under the red LED, the blue LED and dark condition (CK), the mycelium grew faster than that under other light qualities. The white LED resulted in a largest increase in the amount of the mycelium and always kept the activities of CAT high level. Major fluctuations of POD activities emerged under the green LED, while enhanced severely in the late phase. Under the yellow LED, the activities of SOD appeared high level. However, SOD activities on dark (CK) raised obviously in late period. At the late stage, the content of mycelium polysaccharides was significant higher than that under the blue LED. CONCLUSION: The light quality could influence the growth and metabolism of G. lucidum mycelium.

Mutagenic response of 2.45 GHz radiation exposure on rat brain.

PURPOSE: To investigate the effect of 2.45 GHz microwave radiation on rat brain of male wistar strain. MATERIAL AND METHODS: Male rats of wistar strain (35 days old with 130 +/- 10 g body weight) were selected for this study. Animals were divided into two groups: Sham exposed and experimental. Animals were exposed for 2 h a day for 35 days to 2.45 GHz frequency at 0.34 mW/cm(2) power density. The whole body specific absorption rate (SAR) was estimated to be 0.11 W/Kg. Exposure took place in a ventilated Plexiglas cage and kept in anechoic chamber in a far field configuration from the horn antenna. After the completion of exposure period, rats were sacrificed and the whole brain tissue was dissected and used for study of double strand DNA (Deoxyribonucleic acid) breaks by micro gel electrophoresis and the statistical analysis was carried out using comet assay (IV-2 version software). Thereafter, antioxidant enzymes and histone kinase estimation was also performed. RESULTS: A significant increase was observed in comet head (P < 0.002), tail length (P < 0.0002) and in tail movement (P < 0.0001) in exposed brain cells. An analysis of antioxidant enzymes glutathione peroxidase (P < 0.005), and superoxide dismutase (P < 0.006) showed a decrease while an increase in catalase (P < 0.006) was observed. A significant decrease (P < 0.023) in histone kinase was also recorded in the exposed group as compared to the control (sham-exposed) ones. One-way analysis of variance (ANOVA) method was adopted for statistical analysis. CONCLUSION: The study concludes that the chronic exposure to these radiations may cause significant damage to brain, which may be an indication of possible tumour promotion (Behari and Paulraj 2007).