Induced Membrane Lipid Peroxidation Research Articles

Cholesterol Hydroperoxide Co-trafficking in Testosterone-generating Leydig Cells: GPx4 Inhibition of Cytotoxic and Anti-steroidogenic Effects

Trafficking of intracellular cholesterol (Ch) to and into mitochondria of steroidogenic cells is required for steroid hormone biosynthesis. This trafficking is typically mediated by one or more proteins of the steroidogenic acute regulatory (StAR) family. Our previous studies revealed that 7-OOH, a redox-active cholesterol hydroperoxide, could be co-trafficked with Ch to/into mitochondria of MA-10 Leydig cells, thereby inducing membrane lipid peroxidation (LPO) which impaired progesterone biosynthesis. These negative effects of 7-OOH were inhibited by endogenous selenoperoxidase GPx4, indicating that this enzyme could protect against 7-OOH-induced oxidative damage/dysfunction. In the present study, we advanced our Leydig focus to cultured murine TM3 cells and then to primary cells from rat testis, both of which produce testosterone. Using a fluorescent probe, we found that extensive free radical-mediated LPO occurred in mitochondria of stimulated primary Leydig cells during treatment with liposomal Ch+7-OOH, resulting in a significant decline in testosterone output relative to that with Ch alone. Strong enhancement of LPO and testosterone shortfall by RSL3 (a GPx4 inhibitor) and reversal thereof by Ebselen (a GPx4 mimetic), suggested that endogenous GPx4 was playing a key antioxidant role. 7-OOH in increasing doses was also cytotoxic to these cells, RSL3 exacerbating this in Ebselen-reversable fashion. Moreover, GPx4 knockdown increased cell sensitivity to LPO with reduced testosterone output. These findings, particularly with primary Leydigs (which best represent cells in intact testis) suggest that GPx4 plays a key protective role against peroxidative damage/dysfunction induced by 7-OOH co-trafficking with Ch.

Alterations in plasma and erythrocyte membrane fatty acid composition following exposure to toxic copper level affect membrane deformability and fluidity in female wistar rats

BackgroundDeformability and fluidity function of the red blood cell membrane are properties defined by the lipid composition. Toxic copper level induces membrane lipid peroxidation which could cause membrane instability. This study therefore investigated the effect of exposure to toxic copper level for 30 days on red blood cell membrane deformability and fluidity in female Wistar rats. MethodsTwelve (12) female Wistar rats (160 ± 10 g) were randomly grouped (n = 6) into control (given 0.1 ml distilled water p.o.) and copper-toxic (100 mg/kg Copper Sulphate, p.o.), and treated for 30 days. Plasma obtained and RBC membrane prepared from blood collected over EDTA post-treatment were assayed for total cholesterol (TC), phospholipids and fatty acid profile using spectrophotometry and Gas chromatography while heparinized blood was subjected to fragility test. Data were analyzed using student T-test for statistical significance at p < 0.05. Results and conclusionPlasma TC increased by 4.33% while RBC membrane TC decreased by 20.32% in copper-toxic group compared to control. Compared to control, excess copper significantly increased membrane phospholipids level (0.72 ± 0.01 vs 0.59 ± 0.04 mg/dL) but reduced membrane cholesterol/phospholipid ratio (46.61 ± 4.72 vs 72.66 ± 6.47) and stability (by 23.53%). Number of cis- and saturated fatty acids increased in copper-treated plasma and RBC membrane compared to control. Exposure to toxic copper level alters erythrocyte membrane fluidity and deformability by disrupting membrane lipid composition, saturation, bond configuration in phospholipids and permeability.

Cytotoxicity and genotoxicity evaluation of chloroform using Vicia faba roots.

Chloroform is a widely used industrial chemical that can also pollute the environment. The aims of this study were to examine the potential cytotoxicity and genotoxicity of chloroform on plant cells, using the Vicia faba bioassay. Chloroform was evaluated at concentrations of 0.1, 0.5, 1, 2, and 5mg·L-1. The following parameters were analyzed: the mitotic index (MI), micronucleus (MN) frequency, chromosomal aberration (CA) frequency, and malondialdehyde (MDA) content. The results showed that exposure to increasing concentrations of chloroform caused a decrease in MI and an increase in the frequency of MN in Vicia faba root tip cells, relative to their controls. Moreover, various types of CA, including C-mitosis, fragments, bridges, laggard chromosomes, and multipolar mitosis, were observed in the treated cells. The frequency of MN was positively correlated with the frequency of CA in exposure to 0.1-1mg·L-1 chloroform. Furthermore, chloroform exposure induced membrane lipid peroxidation damage in the Vicia faba radicle, and a linear correlation was observed between the MDA content and the frequency of MN or CA. These findings indicated that chloroform exposure can result in oxidative stress, cytotoxicity, and genotoxicity in plant cells.

The original polyethylene microplastics inhibit the growth of sweet potatoes and increase the safety risk of cadmium.

Microplastics (MPs) and heavy metals (HMs) co-exist in sweet potato fields of China. As the main component of agricultural field mulch and one of the most polluting and harmful HMs, the effects of polyethylene microplastics (PE MPs) and cadmium (Cd) on sweet potato and soil environment are remains unclear. Here, pot and hydroponic experiments are used to explore the effects of original and weathered PE MPs on growth and Cd uptake of sweet potatoes. The results of pot experiments reveal that compared with the control (0%), 5% of weathered PE MPs can significantly increase soil electrical conductivity (EC); both 5% of the original PE MPs and weathered PE MPs can significantly reduce the concentration of Olsen phosphorus (P) and Olsen potassium (K) in soil, inhibit plant growth, but significantly increase Cd accumulation and glutathione (GSH) level in tissues of sweet potatoes, and also induce membrane lipid peroxidation. In addition, compared to 5% weathered PE MPs, 5% original PE MPs significantly reduce soil EC, growth and peroxidase level of sweet potatoes, but significantly increase Cd concentration in leaves and stems. The results of hydroponic experiment show that original PE MPs significantly increase the P, K, and Cd adsorption compared with weathered PE MPs, and Cd increases the original PE MPs accumulation in the root cortex but decrease PE MPs accumulation in shoots. To sum up, our study investigates the differences and reasons of the effects of original and weathered PE MPs on growth and Cd absorption of sweet potatoes.

Integrative cytology and proteome alterations unravel the multitarget effect of a novel alkaloid antofine againstPenicillium italicum

AbstractPenicillium italicum is the causal agent of citrus blue mold, which is a major threat to the global citrus fruit industry. Antofine, a natural phenanthroindolizidine alkaloid, is water-soluble and exhibits a broad range of biological activities. However, whether it can inhibit P. italicum growth and the potential inhibitory mechanism remains to be elucidated. This study aimed to investigate the antifungal mechanism of antofine against P. italicum using scanning electron microscopy, transmission electron microscopy (TEM), propidium iodide staining, and tandem mass tag-labeled quantitative proteomic analysis. Antofine was found to exhibit its preeminent antifungal activity against P. italicum with a minimum inhibitory concentration of 1.56 mg/L and a minimum fungicidal concentration of 6.25 mg/L. The challenge test revealed that antofine inhibited the development of citrus blue mold during a 6-d P. italicum-infected period. Antofine acted on its potential multitargets to inhibit P. italicum growth by synergistically activating oxidative stress through accumulating excess reactive oxygen species, impairing membrane integrity, inducing membrane lipid peroxidation, and disrupting mitochondrial function, thereby disrupting the membrane system and reducing cell viability. Moreover, antofine treatment downregulated most differentially expressed proteins involved in carbon metabolism, pyruvate metabolism, and the tricarboxylic acid cycle (TCA) in P. italicum mycelia, which may explain the mitochondrial decomposition observed by TEM and the declines in ATP levels as well as the activities of TCA-related enzymes. These results indicate that antofine treatment inhibited P. italicum growth by targeting the cell membrane and mitochondria.

Oxidative-Stress-Induced Cellular Toxicity and Glycoxidation of Biomolecules by Cosmetic Products under Sunlight Exposure

Cosmetics, commonly known as ‘makeup’ are products that can enhance the appearance of the human body. Cosmetic products include hair dyes, shampoos, skincare, sunscreens, kajal, and other makeup products. Cosmetics are generally applied throughout the face and over the neck region. Sunlight has different wavelengths of light, which include UV-A, UV-B, UV-C, and other radiations. Most cosmetic products have absorption maxima (λmax) in the range of visible light and UV-R. The effect of light-induced photosensitization of cosmetic products, which results in the production of free radicals through type-I and type-II photosensitization mechanisms. Free-radicals-mediated DNA damage and oxidative stress are common consequences of cosmetic phototoxicity. Cosmetic phototoxicity may include percutaneous absorption, skin irritation, eye irritation, photosensitization, mutagenicity, and genotoxicity. Oxidative stress induces membrane lipid peroxidation, glycoxidation, and protein covalent modifications, resulting in their dysfunction. Natural antioxidants inhibit oxidative-stress-induced cosmetic toxicity. Sunlight-induced photodegradation and accumulation of cosmetic photoproducts are also a matter of serious concern. India has tropical weather conditions throughout the year and generally, a majority of human activities such as commerce, agriculture, sports, etc. are performed under bright sunlight conditions. Thus, more focused and dedicated research is warranted to explore the effects of cosmetics on oxidative stress, glycoxidation of biomolecules, and photoproducts accumulation for its total human safety.

Antofine inhibits postharvest green mold due to imazalil-resistant Penicillium digitatum strain Pdw03 by triggering oxidative burst.

The emergence of imazalil (IMZ) resistance in Penicillium digitatum has become a great threat for controlling citrus green mold. In this paper, we investigated the antifungal efficiency and mechanism of an alkaloid antofine against an IMZ-resistant P.digitatum strain Pdw03. Results showed that antofine exhibited a strong antifungal activity against the mycelial growth of strain Pdw03, with a minimum inhibitory concentration (MIC) and the minimum fungicidal concentration (MFC) of 1.56×10-3 and 1.25×10-2 g/L, respectively. In vivo application of antofine effectively delayed the disease progress and reduced the incidence of green mold in citrus fruit. The disease incidence of 10×MFC antofine-treated fruit after 6days of storage was only 11%±4%, which was significantly lower than that of the control (100%±0%). Antofine treatment altered mycelial morphology of strain Pdw03 without affecting the cell wall integrity. Although the ergosterol contents remained stable, a decrease in the total lipid content induced by lipid peroxidation was observed at 30min of exposure, indicating disruption of cell membrane permeability of strain Pdw03. In addition, the mitochondrial membrane potential (MMP) and adenosine triphosphate (ATP) contents were also decreased at 60min of exposure. These results indicated that antofine inhibited the growth of strain Pdw03 by disrupting cell membrane permeability and impairing energy metabolism induced by oxidative burst. PRACTICAL APPLICATIONS: One of the most economically important postharvest diseases of citrus fruit is green mold caused by Penicillium digitatum. The pathogen is mainly controlled by using imazalil, but the prolonged and extensive application of this chemical fungicide has led to emergence of numerous IMZ-resistant strains among P.digitatum isolates. Consequently, new and safe strategies for controlling citrus green mold caused by IMZ-resistant P.digitatum strains are urgently needed. In this study, an alkaloid antofine effectively inhibited the growth of IMZ-resistant P.digitatum strain Pdw03 and significantly decreased green mold incidence in the affected citrus fruits. Antofine induced membrane lipid peroxidation of Pdw03 mycelia, resulting in damage to the cell membrane and impairment of energy metabolism. Antofine is therefore a potential antifungal agent for the control of green mold, which provide theoretical guidance for the food industry.

In vitro and in vivo antifungal activity and preliminary mechanism of cembratrien-diols against Botrytis cinerea

Gray mold, caused by Botrytis cinerea, is one of the major fungal diseases in crops. Botanical fungicides are preferred over chemical fungicides to control gray mold since they are less toxic to the environment and could reverse the resistance to chemical fungicides in pathogens. Cembratrien (CBT)-diols are carbocyclic diterpenes found in abundance in Nicotiana, especially in tobacco inflorescence, and possess a wide range of biological activities. In this study, the antifungal activities of two isomers of CBT-diols (α- and β-CBT-diols) against B. cinerea were evaluated in vitro and in vivo. In addition, the antifungal mechanism was studied on cytoderm, membrane system, and oxidative stress. Results showed that CBT-diols could inhibit wild and multi-resistant strains of B. cinerea, and the half-maximal effective concentration was within 9.67–16.38 μg/mL. The effects of α- and β-CBT-diols were similar but non-synergistic. The inhibition rate of CBT-diols (200 μg/mL) against B. cinerea in different fruits was between 71.9 and 84.2 %. The cellular structure of B. cinerea treated with CBT-diols was observed by scanning electron microscopy, transmission electron microscopy, Crystal violet-Congo red staining, and propidium iodide staining. Results showed that there was almost no change in cytoderm integrity; however, a significant damage to the membrane system integrity was observed, which led to disintegration of the organelles. Cembratrien-diols could increase the activity of chitinase, resulting in an accumulation of N-acetyl-d-glucosamine, which is a precursor for chitin biosynthesis. Cembratrien-diols caused significant increase in conductivity and cellular contents in the culture medium by increasing the membrane permeability of B. cinerea. Furthermore, CBT-diols decreased the levels of essential membrane components such as ergosterol and linoleic acid, but increased the malondialdehyde concentration, which indicated that CBT-diols damaged B. cinerea membrane and induced membrane lipid peroxidation. With growing research, it has been found that the damage to B. cinerea membrane system is mainly associated with the oxidative stress reaction induced by CBT-diols, due to the increase in reactive oxygen species levels and activities of catalase and peroxidase, and the decrease in superoxide dismutase activity and hydrogen peroxide content. The results provide a scientific foundation for the application of CBT-diols as an alternative biological agent against B. cinerea, which may ultimately promote organic fruits and vegetable crops production.

Lemna minor recovery potential after short-term exposure to sulfonylurea herbicide

We have investigated the effects of the sulfonylurea herbicide Sekator OD 375 on common duckweed (Lemna minor L.) and its potential to recover after the herbicide exposure. The plants were exposed to Sekator OD 375 for a 7-day period at the concentrations ranging from 5 to 100 µL L−1, equivalent to 0.005–0.1 of field application rate. The treated plants were transferred to clean fresh growth medium for a 7-day period to observe the plants recovery. The exposure to herbicide significantly reduced the growth rate and the biomass of common duckweeds (L. minor), lowered the content of photosynthetic pigments and induced membrane lipid peroxidation. After the transfer to fresh, clean growth media, the plants exposed to concentrations higher than 50 µL L−1 of herbicide showed no potential to recover. L. minor exposed to relatively low levels of herbicide (below 50 µL L−1) showed a potential to recover their new fronds production: the relative growth rate in the recovery phase was higher than in the exposure period. However, after the recovery phase, the final biomass of the exposed plants was below initial values. Exposure to the herbicide-induced membrane lipid peroxidation (measured as the concentration of malondialdehyde). Thus, plants failed to recover their membranes during the recovery phase and a further increase in the concentrations of malondialdehyde was observed.

Analysis of the synergistic antifungal mechanism of eugenol and citral

The synergistic effects of different essential oils can not only reduce their dosage and cost, but also improve their biological activity. The aim of this study was to evaluate the synergistic antifungal effect of eugenol and citral (SEC) on Penicillium roqueforti. Determination of reactive oxygen species (ROS) and malondialdehyde content indicated that SEC could induce membrane lipid peroxidation, and the contribution of citral was greater than that of eugenol. In addition, downregulation of the gene encoding an NADPH oxidase subunit indicated that the ROS burst induced by SEC was mediated by NADPH oxidase. Scanning electron microscope (SEM) and transmission electron microscope (TEM), propidium iodide treatment, DNA gel electrophoresis and cell leakage experiments showed that SEC destroyed the integrity of the cell membrane and internal structures, and degraded the cell contents, and the contribution of eugenol was greater than that of citral. These results showed that SEC inhibited the activity of P. roqueforti more effectively than eugenol or citral alone, by inducing membrane lipid peroxidation and promoting the ability of eugenol to destroy the cell membrane. The combined agents eventually caused leakage of the cell contents, and ultimately cell death.

Pepper Rootstock and Scion Physiological Responses Under Drought Stress.

In vegetables, tolerance to drought can be improved by grafting commercial varieties onto drought tolerant rootstocks. Grafting has emerged as a tool that copes with drought stress. In previous results, the A25 pepper rootstock accession showed good tolerance to drought in fruit production terms compared with non-grafted plants and other rootstocks. The aim of this work was to study if short-term exposure to drought in grafted plants using A25 as a rootstock would show tolerance to drought now. To fulfill this objective, some physiological processes involved in roots (rootstock) and leaves (scion) of grafted pepper plants were analyzed. Pepper plants not grafted (A), self-grafted (A/A), and grafted onto a tolerant pepper rootstock A25 (A/A25) were grown under severe water stress induced by PEG addition (-0.55 MPa) or under control conditions for 7 days in hydroponic pure solution. According to our results, water stress severity was alleviated by using the A25 rootstock in grafted plants (A/A25), which indicated that mechanisms stimulated by roots are essential to withstand stress. A/A25 had a bigger root biomass compared with plants A and A/A that resulted in better water absorption, water retention capacity and a sustained CO2 assimilation rate. Consequently, plants A/A25 had a better carbon balance, supported by greater nitrate reductase activity located mainly in leaves. In the non-grafted and self-grafted plants, the photosynthesis rate lowered due to stomatal closure, which limited transpiration. Consequently, part of NO3- uptake was reduced in roots. This condition limited water uptake and CO2 fixation in plants A and A/A under drought stress, and accelerated oxidative damage by producing reactive oxygen species (ROS) and H2O2, which were highest in their leaves, indicating great sensitivity to drought stress and induced membrane lipid peroxidation. However, drought deleterious effects were slightly marked in plants A compared to A/A. To conclude, the A25 rootstock protects the scion against oxidative stress, which is provoked by drought, and shows better C and N balances that enabled the biomass to be maintained under water stress for short-term exposure, with higher yields in the field.

Acetonic Extract from the Feijoa sellowiana Berg. Fruit Exerts Antioxidant Properties and Modulates Disaccharidases Activities in Human Intestinal Epithelial Cells.

Feijoa sellowiana fruit has been shown to possess various biological activities, such as anti-bacterial and anti-cancer properties, in a variety of cellular models, but its activity on human intestinal epithelial cells has never been tested. The purpose of this study was to investigate the effects of the acetonic extract of F. sellowiana fruits on the viability, membrane peroxidation, disaccharidases activities and proliferation of in vitro models of human intestinal epithelial cells. To obtain this goal, Caco-2 and HT-29 cells were exposed to the acetonic extract for 24 h. Cell proliferation, viability, lactase and sucrase-isomaltase activity and H2 O2 -induced membrane lipid peroxidation were tested. We found that, compared to control conditions, the acetonic extract significantly increased lactase and sucrase-isomaltase activity in Caco-2, but not HT-29, cells, decreased proliferation, had no effects on viability and restored lipid peroxidation in both cell models. This study suggests that the acetonic extract improves lactase and sucrase-isomaltase activity, inhibits cell proliferation, have no cytotoxic effects and prevent lipid peroxidation of intestinal epithelial cells. These effects may be exploited in case of disaccharidases deficit and also as an adjuvant treatment of diseases related to oxidative stress. Copyright © 2016 John Wiley & Sons, Ltd.

Physical and chemical indices of cucumber seedling leaves under dibutyl phthalate stress.

Phthalic acid ester (PAE) pollution to soil can lead to phytotoxicity in plants and potential health risks to human being. Dibutyl phthalate (DBP) as a kind of PAE has a large usage amount and large residues in soil. To analyze antioxidant responses of plants to DBP stress, effects of varying DBP concentrations on cucumber seedlings growth had been investigated. Malonaldehyde (MDA), hydrogen peroxide (H2O2), chlorophyll, proline, glutathione (GSH), and oxidized glutathione (GSSH) contents and activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD) were studied. The results showed that H2O2 content increased in cucumber seedlings with the increase of DBP concentration. The chlorophyll content in the higher DBP significantly declined compared to the control. In the present study, a disturbance of the GSH redox balance was evidenced by a marked decrease in GSH/GSSG ratio in cucumber seedlings subjected DBP stress. Our results indicated that DBP treatment not only inhibited antioxidant capacity and antioxidant enzyme activity in seedlings' leaves but might also induce chlorophyll degradation or reduce the synthesis of chlorophyll. Moreover, it could also enhance the accumulation of reactive oxygen species (ROS) which induced membrane lipid peroxidation. DBP also altered the ultrastructure of mesophyll cells, damaged membrane structure of chloroplast and mitochondrion, and increased the number and size of starch grains in chloroplasts reducing the photosynthetic capacity.

Physiological and Molecular Responses to Variation of Light Intensity in Rubber Tree (Hevea brasiliensis Muell. Arg.)

Light is one of most important factors to plants because it is necessary for photosynthesis. In this study, physiological and gene expression analyses under different light intensities were performed in the seedlings of rubber tree (Hevea brasiliensis) clone GT1. When light intensity increased from 20 to 1000 µmol m−2 s−1, there was no effect on the maximal quantum yield of photosystem II (PSII) photochemistry (Fv/Fm), indicating that high light intensity did not damage the structure and function of PSII reaction center. However, the effective photochemical quantum yield of PSII (Y(II)), photochemical quenching coefficient (qP), electron transfer rate (ETR), and coefficient of photochemical fluorescence quenching assuming interconnected PSII antennae (qL) were increased significantly as the light intensity increased, reached a maximum at 200 µmol m−2 s−1, but decreased from 400 µmol m−2 s−1. These results suggested that the PSII photochemistry showed an optimum performance at 200 µmol m−2 s−1 light intensity. The chlorophyll content was increased along with the increase of light intensity when it was no more than 400 µmol m−2 s−1. Since increasing light intensity caused significant increase in H2O2 content and decreases in the per unit activity of antioxidant enzymes SOD and POD, but the malondialdehyde (MDA) content was preserved at a low level even under high light intensity of 1000 µmol m−2 s−1, suggesting that high light irradiation did not induce membrane lipid peroxidation in rubber tree. Moreover, expressions of antioxidant-related genes were significantly up-regulated with the increase of light intensity. They reached the maximum expression at 400 µmol m−2 s−1, but decreased at 1000 µmol m−2 s−1. In conclusion, rubber tree could endure strong light irradiation via a specific mechanism. Adaptation to high light intensity is a complex process by regulating antioxidant enzymes activities, chloroplast formation, and related genes expressions in rubber tree.

Protective effect of carrot juice pretreatment on cadmiuminduced oxidative cytotoxic damage to some rat tissues

The effect of pretreatment with carrot juice on the cytotoxic response of the antioxidant defense systems in the liver and kidneys of rats exposed to mild doses of cadmium was examined. Male wistar strain rats (200-250 g b.wt) were exposed to a single daily oral dose of cadmium (3 mg CdCl2/kg) in drinking water for two days following a 5-day oral supplementation with carrot juice as drinking water at the end of which membrane lipid peroxidation, ascorbic acid and glutathione contents and activities of antioxidant enzymes catalase, superoxide dismutase, and cadmium content were determined in the liver and kidney samples and the results subjected to statistical analysis. It was found that pretreatment with carrot juice effectively countered Cd- induced membrane lipid peroxidation, depletion of the non-enzymic antioxidants, ascorbic acid, and glutathione, and induction of the antioxidant enzymes catalase and superoxide dismutase in the liver and kidney as well as effectively reduced cadmium accumulation in the liver and kidney and cadmium-induced liver tissue cell injury, all of which effects are consistent with a protective effect of carrot juice The protective effect of carrot juice pretreatment against Cd-induced lipid peroxidation and tissue ascorbic acid and glutathione depletion was more pronounced in the kidney than in the liver. The active antioxidant principle was not determined but is presumed to be carotenoids.

Prevention of γ-radiation induced cellular genotoxicity by tempol: Protection of hematopoietic system

Tempol (TPL) under in vitro conditions reduced the extent of gamma radiation induced membrane lipid peroxidation and disappearance of covalently closed circular form of plasmid pBR322. TPL protected cellular DNA from radiation-induced damage in various tissues under ex vivo and in vivo conditions as evidenced by comet assay. TPL also prevented radiation induced micronuclei formation (in peripheral blood leucocytes) and chromosomal aberrations (in bone marrow cells) in whole body irradiated mice. TPL enhanced the rate of repair of cellular DNA (blood leucocytes and bone marrow cells) damage when administered immediately after radiation exposure as revealed from the increased Cellular DNA Repair Index (CRI). The studies thus provided compelling evidence to reveal the effectiveness of TPL to protect hematopoietic system from radiation injury.

Effects of anti-lipid peroxidases on frozen-thawed boar spermatozoa

This study evaluated the effects of anti-lipid peroxidases when supplemented to the thawing and incubation media of frozen-thawed boar spermatozoa. Semen pellets were thawed and incubated in media with 1.0 mM α-tocopherol or diethylenetriamine. After 1 h, the acrosome reaction was induced using calcium ionophore A23187, and acrosomes were evaluated using Wells--Awa staining. The number of spermatozoa with fragmented DNA was evaluated using silver staining after single-cell gel electrophoresis. Membrane lipid peroxidation was measured by the end point generation of malondialdehyde. The diethylenetriamine-supplemented media had a higher (P < 0.05) percentage of acrosome-reacted spermatozoa (84.4 ± 4.1%) compared to the control (78.3 ± 4.2%) and α-tocopherol-supplemented (78.0 ± 3.9%). The control had a higher (P < 0.05) percentage of spermatozoa with fragmented DNA (59.3 ± 4.3%) compared to the DETA (28.7 ± 4.1%) and α-tocopherol supplementation (28.0 ± 3.8%). Spermatozoa supplemented with diethylenetriamine had higher amounts (P < 0.05) of malondialdehyde generated (3.60 ± 0.05 μM/10(7) cells) compared to the α-tocopherol supplementation (0.14 ± 0.05 μM/10(7) cells) and the control (0.12 ± 0.05 μM/10(7) cells). These results indicate that supplementing with either 1.0 mM diethylenetriamine or α-tocopherol during semen thawing and incubation protects against DNA fragmentation, and diethylenetriamine increases the percent of spermatozoa capable of completing the acrosome reaction that could induce membrane lipid peroxidation.

Antibiofilm activity of nanosized magnesium fluoride

The ability of bacteria to develop antibiotic resistance and colonize abiotic surfaces by forming biofilms is a major cause of medical implant-associated infections and results in prolonged hospitalization periods and patient mortality. This raises the urgent need to develop compounds that can inhibit bacterial colonization of surfaces. In this study, we present an unreported microwave-based synthesis of MgF2 nanoparticles (Nps) using ionic liquid. We demonstrate the antimicrobial activity of these fluoride nanomaterials and their ability to restrict biofilm formation of common bacterial pathogens. Scanning and transmission electron microscopic techniques indicated that the MgF2·Nps attach and penetrate into the cells. Flow cytometry analysis revealed that the Nps caused a disruption in the membrane potential. The MgF2·Nps also induced membrane lipid peroxidation and once internalized can interact with chromosomal DNA. Based on these findings we further explored the possibility of using the MgF2·Nps to coat surfaces and inhibit biofilm formation. A microwave synthesis and coating procedure was utilized to coat glass coupons. The MgF2 coated surfaces effectively restricted biofilm formation of the tested bacteria. Taken together these results highlight the potential for developing MgF2 nanoparticles in order to inhibit bacterial infections.

Alterations in glutathione reductase, superoxide dismutase, and lipid peroxidation of tadpoles ( Xenopus laevis) exposed to Bonny Light crude oil and its fractions

We determined the effects of sub-lethal levels of Bonny Light crude oil (WC) and its water soluble (WSF) and insoluble (WIF) fractions on malondialdehyde (MDA) and stress enzymes in tadpoles ( Xenopus laevis) following two and 4 weeks exposure at different concentrations. We observed that the treatment of tadpoles with WC, WSF, or WIF decreased the weight of tadpoles, increased MDA levels, and increased superoxide dismutase (SOD) and glutathione reductase (GR) at lower concentrations of exposure and decreased the enzymes at higher doses of exposure. We found that the WC had a lesser negative effect on the parameters of tadpoles compared to the WSF. Longer exposure of tadpoles to WC, WSF, or WIF even at lower concentrations resulted in a negative effect on MDA, SOD, and GR activities The study shows that sub-lethal contaminations with WC, WSF, or WIF induces membrane lipid peroxidation and reduce the ability of tadpoles to produce SOD and GR which may have metabolic costs.

Alterations in Glutathione Reductase, Superoxide Dismutase and Lipid Peroxidation of Tadpoles (Xenopus laevis) Exposed to Bonny Light Crude Oil and its Fractions

We determined the effects of sub-lethal levels of Bonny Light crude oil (WC) and its water soluble (WSF) and insoluble (WIF) fractions on malondialdehyde (MDA) and stress enzymes in tadpoles (Xenopus laevis) following two and 4 weeks exposure at different concentrations. We observed that the treatment of tadpoles with WC, WSF, or WIF decreased the weight of tadpoles, increased MDA levels, and increased superoxide dismutase (SOD) and glutathione reductase (GR) at lower concentrations of exposure and decreased the enzymes at higher doses of exposure. We found that the WC had a lesser negative effect on the parameters of tadpoles compared to the WSF. Longer exposure of tadpoles to WC, WSF, or WIF even at lower concentrations resulted in a negative effect on MDA, SOD, and GR activities The study shows that sub-lethal contaminations with WC, WSF, or WIF induces membrane lipid peroxidation and reduce the ability of tadpoles to produce SOD and GR which may have metabolic costs.