Cell Membrane Lipid Peroxidation Research Articles

Clinical and immunological and microbiological effectiveness of the use of recombinant interleukin 2 in the complex therapy of bacterial meningitis

The article shows the scheme of complex therapy of bacterial meningitis using the recombinant cytokine interleukin 2. The clinical, immunological and microbiological efficacy of the use of recombinant interleukin 2 in the complex therapy of bacterial meningitis is shown. The biological effects of recombinant IL-2 justify its use in the complex therapy of meningitis due to its influence on the activity of metabolic processes at the cellular and subcellular levels, the ability to stabilize the system of lipid peroxidation of cell membranes, to influence the processes of clonal proliferation and differentiation of T- and B-lymphocytes improving the quality of the therapy.

Biochar mitigates arsenic-induced human health risks and phytotoxicity in quinoa under saline conditions by modulating ionic and oxidative stress responses

Arsenic (As) is a toxic metalloid and its widespread contamination in agricultural soils along with soil salinization has become a serious concern for human health and food security. In the present study, the effect of cotton shell biochar (CSBC) in decreasing As-induced phytotoxicity and human health risks in quinoa (Chenopodium quinoa Willd.) grown on As-spiked saline and non-saline soils was evaluated. Quinoa plants were grown on As contaminated (0, 15 and 30 mg kg−1) saline and non-saline soils amended with 0, 1 and 2% CSBC. Results showed that plant growth, grain yield, stomatal conductance and chlorophyll contents of quinoa showed more decline on As contaminated saline soil than non-saline soil. The application of 2% CSBC particularly enhanced plant growth, leaf relative water contents, stomatal conductance, pigment contents and limited the uptake of As and Na as compared to soil without CSBC. Salinity in combination with As trigged the production of H2O2 and caused lipid peroxidation of cell membranes. Biochar ameliorated the oxidative stress by increasing the activities of antioxidant enzymes (SOD, POD, CAT). Carcinogenic and non-carcinogenic human health risks were greatly decreased in the presence of biochar. Application of 2% CSBC showed promising results in reducing human health risks and As toxicity in quinoa grown on As contaminated non-saline and saline soils. Further research is needed to evaluate the role of biochar in minimizing As accumulation in other crops on normal as well as salt affected soils under field conditions.

Amylin Dyshomeostasis Hypothesis: Small Vessel-Type Ischemic Stroke in the Setting of Type-2 Diabetes.

Recent histological analyses of human brains show that small vessel-type injuries in the setting of type-2 diabetes colocalize with deposits of amylin, an amyloid-forming hormone secreted by the pancreas. Amylin inclusions are also identified in circulating red blood cells in people with type-2 diabetes and stroke or cardiovascular disease. In laboratory models of type-2 diabetes, accumulation of aggregated amylin in blood and the cerebral microvasculature induces brain microhemorrhages and reduces cerebral blood flow leading to white matter ischemia and neurological deficits. At the cellular level, aggregated amylin causes cell membrane lipid peroxidation injury, downregulation of tight junction proteins, and activation of proinflammatory signaling pathways which, in turn, induces macrophage activation and macrophage infiltration in vascular areas positive for amylin deposition. We review each step of this cascade based on experimental and clinical evidence and propose the hypothesis that systemic amylin dyshomeostasis may underlie the disparity between glycemic control and stroke risk and may be a therapeutic target to reduce the risk of small vessel ischemic stroke in patients with type-2 diabetes.

Cadmium stress alleviation potential of Bruguiera cylindrica (L.) Blume enhances in combination with NaCl

A hydroponic experiment in NaCl tolerant mangrove, Bruguiera cylindrica plantlets was done to investigate the interactive effects of CdCl2+NaCl as well as the individual effects of CdCl2. CdCl2 alone results in enhanced level of cell membrane lipid peroxidation, damaging normal structure, and function of the membrane and there by leading to reduction of membrane stability index and thus severely promoting the electrolyte leakage than the combined treatment of CdCl2+NaCl. Antioxidants greatly contribute to cope with the stress by scavenging ROS and were more prominent in individual stress than combined stress. B. cylindrica can be categorized as a highly tolerant mangrove species with a Tolerance Index (TI) of above 60% toward CdCl2+NaCl (TI is 70 and 75% in leaf and root). But TI was only 63 and 67% in leaf and root, respectively, on exposure to CdCl2 alone indicating that this plant is less tolerant to Cd alone. The existence of B. cylindrica depends on the heavy metals being introduced into the mangrove ecosystem and imparts a combination stress along with NaCl. In this regard, B. cylindrica survives up to 0.20 mM CdCl2 along with NaCl. Thus, the high NaCl tolerance mechanisms in this mangrove species could be equally efficient in imparting tolerance toward high concentration of Cd along with NaCl and exhibits phytostabilization in polluted coastal wetlands.

Role of Suillus placidus in Improving the Drought Tolerance of Masson Pine (Pinus massoniana Lamb.) Seedlings

Masson pine is an important afforestation species in southern China, where seasonal drought is common. The present study focused on the effects of Suillus placidus, an ectomycorrhizal fungus, inoculation on the growth and physiological and biochemical performance of masson pine seedlings under four different watering treatments (well-watered, mild drought, moderate drought, and severe drought) to evaluate the symbiotic relationship between S. placidus and masson pine seedlings. Ectomycorrhizal-inoculated (ECM) and non-inoculated (NM) seedlings were grown in pots and maintained for 60 days using the weighing method. Results showed that seedlings’ growth, dry weight, RWC, chlorophyll content, PSII efficiency, and photosynthesis decreased as drought stress intensified in both ECM and NM plants. This suggests that drought stress significantly limits the growth and photosynthetic performance of masson pine seedlings. Nevertheless, increased An/gs and proline contents in both NM and ECM prevented oxidative damage caused by drought stress. In addition, increased peroxidase (POD) activity is an essential defense mechanism of ECM seedling under drought stress. Compared with NM, ECM seedlings showed faster growth, higher RWC, and photosynthetic performance, and lower lipid peroxidation in cell membranes under drought stress, as indicated by higher POD activity and lower proline and malondialdehyde (MDA). Our experiment found that S. placidus inoculation can enhance the drought resistance of masson pine seedlings by increasing antioxidant enzyme activity, water use efficiency, and proline content, thereby enhancing growth under water-deficiency conditions. S. placidus can be used to cultivate high-quality seedlings and improve their survival in regions that experience seasonal droughts.

Ecotoxicological responses of Eisenia andrei exposed in field-contaminated soils by sanitary sewage

The disposal of untreated sanitary sewage in the soil has several consequences for human health and leads to environmental risks; thus, it is necessary investigating, monitoring and remediating the affected sites. The aims of the current study are to evaluate ecotoxicological effects on Eisenia andrei earthworms exposed to soil subjected to sources of sanitary sewage discharge and to investigate whether prevention values established by the Brazilian legislation for soil quality, associated with the incidence of chemical substances in it, are satisfactory enough to assure the necessary quality for different organisms. Earthworms’ behavior, reproduction, acetylcholinesterase activity, catalase, superoxide dismutase and malondialdehyde levels were evaluated. The reproduction and behavior of earthworms exposed to sanitary sewage were adversely affected. Increased superoxide dismutase and catalase activity acted as antioxidant defense mechanism. Significantly increased lipid peroxidation levels and acetylcholinesterase activity inhibition have indicated lipid peroxidation in cell membrane and neurotransmission changes, respectively. Results have confirmed that sanitary sewage induced oxidative stress in earthworms. In addition, based on biochemical data analysis, the integrated biomarker response (IBR) has evidenced different toxicity levels in earthworms between the investigated points. Finally, results have indicated that effluents released into the soil, without proper treatment, lead to contaminant accumulation due to soil saturation and it can hinder different processes and biological development taking place in the soil. In addition, the current study has shown that physical-chemical analyses alone are not enough to assess soil quality, since it is also requires adopting an ecotoxicological approach. Brazilian legislation focused on soil quality must be revised and new guiding values must be proposed.

The ThSOS3 Gene Improves the Salt Tolerance of Transgenic Tamarix hispida and Arabidopsis thaliana.

The salt overly sensitive (SOS) signal transduction pathway is one of the most highly studied salt tolerance pathways in plants. However, the molecular mechanism of the salt stress response in Tamarix hispida has remained largely unclear. In this study, five SOS genes (ThSOS1–ThSOS5) from T. hispida were cloned and characterized. The expression levels of most ThSOS genes significantly changed after NaCl, PEG6000, and abscisic acid (ABA) treatment in at least one organ. Notably, the expression of ThSOS3 was significantly downregulated after 6 h under salt stress. To further analyze ThSOS3 function, ThSOS3 overexpression and RNAi-mediated silencing were performed using a transient transformation system. Compared with controls, ThSOS3-overexpressing transgenic T. hispida plants exhibited greater reactive oxygen species (ROS)-scavenging capability and antioxidant enzyme activity, lower malondialdehyde (MDA) and H2O2 levels, and lower electrolyte leakage rates under salt stress. Similar results were obtained for physiological parameters in transgenic Arabidopsis, including H2O2 and MDA accumulation, superoxide dismutase (SOD) and peroxidase (POD) activity, and electrolyte leakage. In addition, transgenic Arabidopsis plants overexpressing ThSOS3 displayed increased root growth and fresh weight gain under salt stress. Together, these data suggest that overexpression of ThSOS3 confers salt stress tolerance on plants by enhancing antioxidant enzyme activity, improving ROS-scavenging capability, and decreasing the MDA content and lipid peroxidation of cell membranes. These results suggest that ThSOS3 might play an important physiological role in salt tolerance in transgenic T. hispida plants. This study provides a foundation for further elucidation of salt tolerance mechanisms involving ThSOSs in T. hispida.

Antagonistic Interaction between Phosphinothricin and Nepeta rtanjensis Essential Oil Affected Ammonium Metabolism and Antioxidant Defense of Arabidopsis Grown In Vitro.

Phosphinothricin (PPT) is one of the most widely used herbicides. PTT targets glutamine synthetase (GS) activity in plants, and its phytotoxicity is ascribed to ammonium accumulation and reactive oxygen species bursts, which drives rapid lipid peroxidation of cell membranes. In agricultural fields, PPT is extensively sprayed on plant foliage; however, a portion of the herbicide reaches the soil. According to the present study, PPT absorbed via roots can be phytotoxic to Arabidopsis, inducing more adverse effects in roots than in shoots. Alterations in plant physiology caused by 10 days exposure to herbicide via roots are reflected through growth suppression, reduced chlorophyll content, perturbations in the sugar and organic acid metabolism, modifications in the activities and abundances of GS, catalase, peroxidase, and superoxide dismutase. Antagonistic interaction of Nepeta rtanjensis essential oil (NrEO) and PPT, emphasizes the existence of complex control mechanisms at the transcriptional and posttranslational level, which result in the mitigation of PPT-induced ammonium toxicity and in providing more efficient antioxidant defense of plants. Simultaneous application of the two agents in the field cannot be recommended; however, NrEO might be considered as the PPT post-treatment for reducing harmful effects of herbicide residues in the soil on non-target plants.

Effects of non-thermal plasma technology on Diaporthe longicolla cultures and mechanisms involved.

The Diaporthe/Phomopsis complex (D/P) is a group of soybean seed-borne fungi. The use of chemical fungicides, either for seed treatment or during the crop cycle, is the most adopted practice for treating fungal diseases caused by this complex. Worldwide, there is a search for alternative seed treatments that are less harmful to the environment than chemicals. Non-thermal plasma (NTP) is a novel seed treatment technology for pathogen removal. This research aimed to evaluate the effects of NTP on the in vitro performance of pure cultures of Diaporthe longicolla and elucidate the mechanisms underlying these effects. Active D. longicolla mycelium, growing in vitro, was exposed to different NTP treatments, employing a dielectric barrier discharge arrangement with different carrier gases (N2 or O2 ). Fungal growth, fresh biomass and colony appearance were negatively affected by plasma treatments (TN3 and TO3). Lipid peroxidation and antioxidant activities were higher in plasma-treated colonies comparison with non-exposed colonies (control). Fungal asexual spores (conidia) were also exposed to NTP, showing high susceptibility. Exposure of D. longicolla colonies to NTP severely compromised fungal biology. Ozone production during treatment and lipid peroxidation of fungal cell membranes appeared to be involved in the observed effects. © 2020 Society of Chemical Industry.

Dihydroartemisinin Induces Ferroptosis in HCC by Promoting the Formation of PEBP1/15-LO.

Relevant researches have recognized the vital role of inducing ferroptosis in the treatment of tumor. The latest findings indicate that PEBP1/15-LO can play an essential role in the process of cell death. However, its role in regulating ferroptosis in hepatocellular carcinoma (simplified by HCC) remains unclear. The previous research of our team has proved that DHA can induce ferroptosis of hepatic stellate cells. In this study, we found that DHA could also induce ferroptosis in HCC cells. Interestingly, DHA induced ferroptosis by promoting the formation of PEBP1/15-LO and promoting cell membrane lipid peroxidation. In addition, we also found that DHA had no obvious regulatory effect on 15-LO, but it could promote PEBP1 protein expression. Importantly, we discovered the upregulation of PEBP1 induced by DHA was related to the inhibition of its ubiquitination degradation. In vivo experiments have also obtained consistent results that DHA can inhibit tumor growth and affect the expression of ferroptosis markers in tumor tissues, which would be partially offset by interference with PEBP1.

Lateral size of graphene oxide determines differential cellular uptake and cell death pathways in Kupffer cells, LSECs, and hepatocytes.

As a representative two-dimensional (2D) nanomaterial, graphene oxide (GO) has shown high potential in many applications due to its large surface area, high flexibility, and excellent dispersibility in aqueous solutions. These properties make GO an ideal candidate for bio-imaging, drug delivery, and cancer therapy. When delivered to the body, GO has been shown to accumulate in the liver, the primary accumulation site of systemic delivery or secondary spread from other uptake sites, and induce liver toxicity. However, the contribution of the GO physicochemical properties and individual liver cell types to this toxicity is unclear due to property variations and diverse cell types in the liver. Herein, we compare the effects of GOs with small (GO-S) and large (GO-L) lateral sizes in three major cell types in liver, Kupffer cells (KCs), liver sinusoidal endothelial cells (LSECs), and hepatocytes. While GOs induced cytotoxicity in KCs, they induced significantly less toxicity in LSECs and hepatocytes. For KCs, we found that GOs were phagocytosed that triggered NADPH oxidase mediated plasma membrane lipid peroxidation, which leads to PLC activation, calcium flux, mitochondrial ROS generation, and NLRP3 inflammasome activation. The subsequent caspase-1 activation induced IL-1β production and GSDMD-mediated pyroptosis. These effects were lateral size-dependent with GO-L showing stronger effects than GO-S. Amongst the liver cell types, decreased cell association and the absence of lipid peroxidation resulted in low cytotoxicity in LSECs and hepatocytes. Using additional GO samples with different lateral sizes, surface functionalities, or thickness, we further confirmed the differential cytotoxic effects in liver cells and the major role of GO lateral size in KUP5 pyroptosis by correlation studies. These findings delineated the GO effects on cellular uptake and cell death pathways in liver cells, and provide valuable information to further evaluate GO effects on the liver for biomedical applications.

Bioactive compounds, phenolic profile, antioxidant capacity and effectiveness against lipid peroxidation of cell membranes of Mauritia flexuosa L. fruit extracts from three biomes in the Ecuadorian Amazon

The bioactive compounds, total antioxidant capacity and protective effect against lipid oxidative damage of red blood cell (RBC) membranes of Mauritia flexuosa L. extracts from three altitude levels (low, middle and high zones) were analyzed. The identification of the main polyphenols in the fruit was performed using High Performance Liquid Chromatography/Electrospray Ionization Tandem Mass Spectrometry analysis, while High-Performance Liquid Chromatography - Diode Array Detector was applied for the vitamin C and carotenoid analysis. The ability of the extracts (methanolic, free polyphenols and bound polyphenols) to protect RBC membranes against oxidative destruction was assessed utilizing the thiobarbituric acid reactive substance assay (TBARS) assay. Among the 14 phenolic compounds identified, quercetin glycosides were the most predominant ones. The fruit from the middle altitude zone showed higher vitamin C and lutein contents than those from the low and high areas, whilst higher values of β-Carotene were obtained in M. flexuosa L. from the low zone. The contents of flavonoids and total polyphenols were lower in fruit from the low zone, whilst the fruit from the middle zone had the highest values. Similar results were observed in the results of the antioxidant capacity assays. However, a significant difference was not found in the protective effect of the extracts from the three altitude zones against lipid peroxidation in RBC membranes.

Пероксидне окиснення ліпідів клітинних мембран у формуванні та регуляції захисних реакцій рослин

Пероксидне окиснення ліпідів клітинних мембран у формуванні та регуляції захисних реакцій рослин

Abstract 480: Molecular mechanism of action of photoimmunotherapy with antibody-IR700 dye conjugates

Abstract INTRODUCTION: Cancer cell-targeted photoimmunotherapy (PIT) is a platform technology under development for the treatment of various cancers. PIT is a drug and device combination that utilizes an antibody conjugated to the IR700 (IRDye 700DX®) light-excitable dye, which upon antigen binding and illumination with non-thermal red light, leads to necrotic cell death. The objective of these studies was to characterize the molecular pharmacology and the underlying mechanism of action of PIT. METHODS: In vitro PIT studies using human and mouse cancer cells were performed to evaluate conjugate (antibody + dye) binding, dose response and light dosimetry response. Mouse xenograft experiments assessed necrotic markers in tumor tissue and surrounding normal tissue post-PIT treatment. Oxidative damage to lipids was detected with a reporter dye. Mass spectrometry analysis was performed to assess protein oxidation, crosslinking and axial ligand dissociation from the dye. RESULTS: Binding of the conjugate to the target cancer cells was required for PIT treatment to induce cell death as measured by antibody competition studies, however, internalization of the conjugate was not required for cytotoxic effects. Administration of non-thermal red light to the target cells bound with the conjugate led to morphologic changes and membrane disruption within minutes, and necrotic cell death was observed in a conjugate- and light-dose dependent manner. Requirement of conjugate binding to the cancer antigen provided high level of tumor specificity as demonstrated by lack of damage to normal surrounding tissue after PIT treatment. Light excitation of the conjugate generated 1O2 with high quantum yield. In vitro PIT treatment led to cell membrane lipid peroxidation, mediated by 1O2 as shown by abrogation with sodium azide, a selective 1O2 quencher. In addition, protein oxidation, cross-linking and aggregation of the conjugate was observed. In low oxygen concentrations and in the presence of ascorbate, photo-induced dissociation of axial ligands from the dye was detected. CONCLUSIONS: These studies suggest the molecular mechanism of action of PIT includes generation of 1O2 that leads to lipid peroxidation and cell membrane disruption. Additional mechanisms may include protein oxidation and non-oxygen dependent mechanisms such as axial ligand loss of the IR700 dye. These results describe a biophysical process that damages and disrupts the cell membrane integrity resulting in necrotic cell death and immunogenic cell death. Citation Format: Roger Heim, Lew Makings, Torsten Wiemann, Anthony Manibusan, Miguel Garcia-Guzman. Molecular mechanism of action of photoimmunotherapy with antibody-IR700 dye conjugates [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 480.

Radiomodulators as Agents of Biological Protection against Oxidative Stress under the Influence of Ionizing Radiation

The potential mechanisms of radioprotective effect of radiomodulators as agents of “biological” protection against oxidative stress in conditions of acute and chronic irradiation at high- and low-dose-rate ionizing radiation are considered. Radiomodulators, as natural antioxidants, prevent lipid peroxidation of cell membranes and reduce radiation toxemia. The radioprotective and radiomitigative properties of natural antioxidants are limited in terms of a dose reduction factor of 1.15–1.2. The dose–effect interrelation of antioxidants has a dome-shaped character; they can be prooxidants under certain conditions. With this mechanism they are also able to reduce acute toxicity of medicines and poisons. Long, low-intensive radiation at more than 100 mSv/year causes the development of oxidative stress with activation of the mechanisms of antioxidant defense upon its further exhaustion with a decrease in the ascorbic acid content in tissues and endogenous reduced thiols. In this case, the use of natural antioxidants allows a reduction in manifestations of oxidative stress via substrate therapy, thereby compensating for vitamin deficiency under the conditions of their intense consumption. At the same time, the delivery of exogenous purine nucleoside favors the synthesis of DNA and RNA in the course of their postradiation repair. In the condition of oxidative stress, the basis of adaptation shifts in the antioxidant system eventually consists of activation of the nuclear factor Nrf2 and NAD-dependent histone deacetylases sirtuins. Via hormesis, plant polyphenols, coumarins, purine nucleosides, and melatonin can modulate the Nrf2 nuclear factor and sirtuin activity and reduce the remote consequences of chronic radiation exposure, such as a reduction of the human lifespan, by a delay of the development of atherosclerosis, cardiovascular, and neurodegenerative diseases, metabolic syndrome, diabetes mellitus, and the risk of carcinogenesis.

Effects of seed moisture content and Epichloe endophyte on germination and physiology of Achnatherum inebrians

Vertically transmitted Epichloe endophyte can be beneficial to host grasses. In order to achieve high seed and endophyte viability under storage, knowledge of optimal seed moisture content and germination behavior of endophyte-infected grass seed is required. In the current research project, Achnatherum inebrians seeds were adjusted to different moisture contents to investigate effects on germination and viability of the endophyte, E. gansuensis, after six months of storage. To explore mechanism of the effect of moisture content and endophyte on seed germination, a number of physiological and biochemical indicators were determined, including electrical conductivity (EC), contents of proline (Pro), malondialdehyde (MDA) and total soluble sugar; activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and hydrogen peroxide (H2O2). The results showed that the viability of the endophyte at 5.5% and 9.5% seed moisture was significantly (p<0.05) higher than with other seed moisture treatments. Furthermore, the infection rate was higher than the corresponding germination percentage at each seed moisture content. The endophyte significantly (p<0.05) improved the seed germination percentage, germination index, and vigor index at the seed moisture contents of 5.5% and 9.5%. A value of 5.5% was found to be the optimal seed moisture content under storage. This moisture level enhanced the activity of antioxidant enzymes and reduced lipid peroxidation of cell membranes, which is likely to be responsible for the slowing of which is likely to be responsible for the slowing of the decline in viability of Achnatherum inebrians seeds. Compared to the seed with endophyte, uninfected seeds had lower soluble sugar and proline contents. We conclude that the presence of the endophyte can improve vigor of A. inebrians seed after prolonged storage at low and intermediate moisture levels.

Nutritional muscular dystrophy in lambs reared on pasture in semiarid region of Brazil

This article presents important data on the diagnosis of nutritional muscular dystrophy (NMD) in sheep reared in the semiarid region of Northeast Brazil, with a focus on medical clinic data, nutritional management, anatomopathological aspects and quantification of serum selenium by highly sensitive analytical methodology. The semiarid region of Brazil is of great importance in the creation of small ruminants and many diseases that affect herds are related to failures in nutritional management, sanitary measures, periods of greater drought or low rainfall, little availability of native forage at certain times of the year and lack of supplementation with energy nutrients, proteins and minerals. The lack of publications on outbreaks of selenium deficiency demonstrates the importance of diagnosing in this area. The mean concentration of Se in the serum from the lambs was very low (2.52±1.02µg/L). The findings in the skeletal muscles are compatible with the characteristics observed in NMD, characterized by necrosis and calcification of myofibrils. In addition, necrotizing vasculitis in hepatic arterioles and hepatocellular coagulation necrosis in hepatocytes were observed, probably triggered by lipid peroxidation of cell membranes. The lambs from this outbreak, reared on pasture in the semiarid region, presented low serum Se concentration, with clinical and anatomopathological manifestation of NMD. Thus, supplementation with Se in the diet should be recommended regularly to avoid the appearance of new cases. Serum Se levels are useful indicators for the diagnosis of nutritional muscular dystrophy in lambs, associated with clinical and anatomopathological data.

Heliotropium thermophilum, an extreme heat tolerant species, promises plants about adaptation to high soil temperature conditions.

To understand high temperature tolerance, Heliotropium thermophilum, a flowering plant thriving in a geothermal field with a soil temperature ranging between 55 and 65°C, was grown in controlled laboratory conditions and two different soil temperatures were applied to the plants. One of them was the control group (CT 25 ± 3°C) and the other was the high temperature group (HT 60 ± 4°C). Water potential, dry weight, cell membrane injury (CMI), lipid peroxidation, hydrogen peroxide, chlorophylls, carotenoids, flavonoids, anthocyanins, proline and total soluble sugar contents were measured. Contents of total soluble sugars, phenolics, flavonoids, anthocyanins, proline were found to be higher in HT group than CT while CMI was opposite. Moreover, no difference was determined in water potential, dry weight, lipid peroxidation, total chlorophyll and carotenoids between CT and HT. H. thermophilum plants adapted to high temperature under laboratory conditions through changing membrane lipid saturation, accumulating osmotically active compounds to save water or increase its uptake and inducing antioxidants such as phenolic compounds to keep reactive oxygen species under control. In conclusion, this study showed that H. thermophilum plant was highly resistant to high soil temperature under optimized laboratory conditions. Moreover, a plant that can withstand 60°C for a long period of time up to 60days under laboratory conditions was reported for the first time.

Enhancement of membrane lipid peroxidation in lung cancer cells irradiated with monoenergetic X-rays at the K-shell resonance absorption peak of phosphorus.

The aim of this study was to determine whether membrane lipid peroxidation in mammalian cells is enhanced by X-ray irradiation at the K-shell resonance absorption peak of phosphorus. A549 and wild-type p53-transfected H1299 (H1299/wtp53) cell lines derived from human lung carcinoma were irradiated with monoenergetic X-rays at 2.153 keV, the phosphorus K-shell resonance absorption peak, or those at 2.147 or 2.160 keV, which are off peaks. Immunofluorescence staining for 4-hydroxy-2-nonenal (HNE), a lipid peroxidation product, was used as marker for protein modification. In both cell lines, the HNE production was significantly enhanced after irradiation at 2.153 keV compared to sham-irradiation. The enhancement (E) was calculated as the ratio of the fluorescence intensity of irradiated cells to that of sham-irradiated cells. In both the cell lines, E2.153 was significantly larger than E2.147 and no significant difference between E2.147 and E2.160 was observed. The extra enhancement at 2.153 keV was possibly caused by energy transition within the phosphorus K-shell resonance absorption. Our results indicate that membrane lipid peroxidation in cells is enhanced by the Auger effect after irradiation at the K-shell resonance absorption peak of phosphorus rather than by the photoelectric effect of the constituent atoms in the membrane lipid at 2.147 keV.

Ethylene Signals Involved in Salicylic Acid to Improve Cold Resistance of Postharvest Plum Fruits

In order to study the effect of salicylic acid on the cold resistance of postharvest plum fruits and its relationship with ethylene signal,in this study,medium-maturation(Bulang)plum fruits were used as materials. It were treated with 1.0 mmol/L SA and 1.0 μL/L 1-MCP separately and in combination,and treated with distilled water as a control group. The effects of the above treatment on the chilling injury rate,chilling injury index,peroxidase(POD),polyphenol oxidase(PPO),cell membrane permeability,malondialdehyde(MDA)content,superoxide dismutase(SOD)and catalase(CAT)activities of plum fruits under storage conditions at 4℃ were analyzed. The results showed that SA treatment could significantly reduce the chilling injury rate and chilling injury index(P<0.05),delay the increase of POD and PPO activity,delay flesh browning,mitigate chilling injury symptoms. Moreover,it could also augment the activities of SOD and CAT(P<0.05),and maintain lower levels of cell membrane permeability and MDA. Thereby,it had a certain inhibitory effect on the occurrence of cell membrane lipid peroxidation. The experiment also found that SA combined with 1-MCP treatment significantly inhibited the occurrence of chilling injury in the middle of storage(P<0.05),but the accumulation rate of chilling injury was higher than that of SA treatment,and 1-MCP treatment accelerated the accumulation of chilling damage. The above results indicate that the appropriate concentration of exogenous SA treatment can enhance the cold resistance of plum fruit after harvest,and ethylene signal participates in the process,but it is not a dependent factor.