Activities Of Various Enzymes Research Articles

Oral administration of Bifidobacterim bifidum for modulating microflora, acid and bile resistance, and physiological indices in mice.

Bifidobacteria are generally acknowledged as major gut microflora used as probiotics, which promote human health. In this study, the effects of the administration of Bifidobacterim bifidum on modulating gastrointestinal (GI) tract microflora, acid and bile resistance, and physiological indices in BALB/c mice were investigated. Results showed that B. bifidum can significantly improve the ecosystem of the GI tract by increasing the amount of probiotics and reducing the populations of pathogenic bacteria, as measured by plate count and real-time PCR. After exposure to simulated GI tract conditions, the growth of gut microflora in the B. bifidum group was higher than that in the control group when incubated for 12 h in MRS or nutrient broth adjusted to pH 2.0 or 3.0 or in the presence of a concentration of bile salt (0.45% m/v). The blood biochemical index was examined, and the physiological effect of the cell-free extract of gut microflora was evaluated by measuring the activity of various enzymes, including α-glucosidases, esterase, and lactate dehydrogenase. This study suggested that a B. bifidum strain can stabilize blood sugar, lower cholesterol levels in serum, and improve metabolic activity. Moreover, B. bifidum was a promising enhancer of microbial diversity in mouse intestine and played a vital role in human physiological processes, which can benefit the health of a host.

Acid sphingomyelinase is activated in sickle cell erythrocytes and contributes to inflammatory microparticle generation in SCD

AbstractSphingolipids are a class of lipids containing a backbone of sphingoid bases that can be produced de novo through the reaction of palmitate and serine and further metabolized through the activity of various enzymes to produce intermediates with diverse roles in cellular processes and signal transduction. One of these intermediates, sphingosine 1-phosphate (S1P), is stored at high concentrations (1 μM) in red blood cells (RBCs) and directs a wide array of cellular processes mediated by 5 known G-protein coupled receptors (S1P1-S1P5). In this study, we show that RBC membrane alterations in sickle cell disease enhance the activation acid sphingomyelinase by 13%, resulting in increased production and storage of sphingosine (2.6-fold) and S1P (3.5-fold). We also show that acid sphingomyelinase enhances RBC-derived microparticle (MP) generation. These MPs are internalized by myeloid cells and promote proinflammatory cytokine secretion and endothelial cell adhesion, suggesting that potential crosstalk between circulating inflammatory cells and MPs may contribute to the inflammation-rooted pathogenesis of the disease. Treatment with amitriptyline reduces MP generation in vitro and in vivo and might be used to mitigate inflammatory processes in sickle cell disease.

Two signals for maximal T cell activation

Immunology T cell activation requires increased intracellular calcium and the activity of various enzymes, such as the kinase Itk. Wang et al. report that two signals, calcium and lipids, converged on Itk for maximal activation of T cells. The same region of the Itk protein bound to the signaling lipid PI(3,4,5)P3 and to the calcium-binding protein calmodulin. PI(3,4,5)P3 and calmodulin enhanced the binding of each other to Itk. The binding of both PI(3,4,5)P3 and calmodulin was necessary so that T cells produced maximal levels of an inflammatory cytokine, interleukin-17A. Sci. Signal. 7 , ra74 (2014).

Health-Promoting Components and Related Enzyme Activities of Muskmelon Fruit During its Development and Ripening

The present investigation aimed to determine the sugars (reducing, nonreducing) and antioxidants, such as phenols, polyphenols, carotenoids and total antioxidant activity, as well as activities of various enzymes related to these biochemical components in muskmelon at its different developmental stages. The quantity of phenolic compounds (total phenols, total polyphenols) and lycopene was accumulated significantly in ripened stage of muskmelon fruit. The highest levels of activities of sucrose phosphate synthase and sucrose synthase were recorded in the fruit thereby indicating positive correlation with the sucrose accumulation as fruit approaches ripening. β-galactosidase, polygalacturonase and cellulase exhibited their positive relation with the softening process. Hence, the present study confirms the muskmelon fruit as a nutritionally balanced source of sugars and antioxidants. Practical Application The present study has importance from its practical perspective as the comprehensive assessment of sugars, antioxidants and their related enzymes of muskmelon revealed this fruit as a nutritionally potential one. Antioxidants present in the muskmelon fruit scavenge free radicals and thereby protect its consumers. In the present study, the accumulation of phenols and polyphenols confirms their health-promoting role in muskmelon beyond basic nutrition. Therefore, orange-fleshed muskmelon fruit extracts have the potential to be developed into nutraceuticals and dietary supplements. Furthermore, identification of health-promoting properties of muskmelon fruit may encourage its increased production and consumption.

Calcium bioavailability from dairy products and its release from food by in vitro digestion

Food products are an exclusive source of nutrients necessary for the development and proper functioning of human organism. The key issue in nutrition is the bioavailability of nutrients rather than the supply of their adequate amounts in a diet. Calcium is the basic structural element of bones and teeth. It is also an element with a wide range of physiological functions, e.g. it is responsible for the right excitability of muscular and nervous system, normal heart function, hormonal secretion, blood clotting, cell membrane permeability and activation of various enzymes. It is universally acknowledged that the main source of calcium for a human organism is milk and dairy products, owing to their rich content and high availability of calcium. However, certain stages in food processing technologies may depress the high bioavailability of dietary nutrients. In this paper, long-term research findings about the bioavailability of calcium in milk products have been summarized, in addition to the information about calcium uptake from bread or other popular breakfast meals composed of milk products in combination with cereal component. The popular opinion that milk and other dairy products are the best and most valuable source of highly available calcium has indeed been supported. However, an in vitro study demonstrates that an addition of cereal to milk or yoghurt significantly diminishes the quantity of calcium released during digestion, which could contribute to the development of calcium insufficiency or augmentation of its symptoms.

Minotoring adenine nucleotides levels and their relevance to biochemical and cellular metabolic function using bioluminescence‐based strategies (766.5)

Adenine nucleotides are major determinants of the energy status of the cell and thus any modulation of their cellular concentration has significant consequences to cellular metabolism, cellular growth and cell death. ATP generating enzymes are usually involved in anabolic processes while ATP consuming enzymes are involved in catabolite processes. We have developed biochemical and cell based assays that monitor the concentrations of ATP, ADP and AMP in biochemical reactions and in cells. These universal assays can measure the activity of various enzymes with no modification of the native substrate and the ability to use diverse substrates such as proteins, peptides, lipids, sugars, etc. The AMP generating reactions such as ubiquitin ligases, aa aminoacyl t‐RNA synthetases, DNA ligases, cAMP‐dependent phosphodiesterases, etc. can be also monitored with high sensitivity and reproducibility. The ADP‐generating (kinases and ATPases, and ATP‐consuming reactions (kinases and ATPases) can be monitored as well using this luminescent approach. We will also show data using luminescent technology to monitor the cellular levels of these adenine nucleotides under various stress and physiological conditions.

Evaluation of antioxidant enzymes in response to predator odor stress in prefrontal cortex and amygdala

Conditions of stress can originate from diverse stimuli including physical, chemical, antigenic and psychological. The latter is processed in part via the hypothalamic-pituitary-adrenal (HPA) axis, with input from and communication between the amygdala (AM) and prefrontal cortex (PFC). The HPA axis generates an increase in circulating glucocorticoids, augmenting metabolism and, consequently, oxygen consumption, increasing the production of free radicals and reactive oxygen species (ROS). Exposure to predator odor as a model of non-invasive acute stress was used to evaluate the hypothesis that psychogenic stress can modify enzymatic antioxidant responses. The activities of various enzymes, catalase (CAT), cytosolic and mitochondrial superoxide dismutase (Cu, Zn-SOD and Mn-SOD, respectively) and glutathione S-transferase (GST), were determined in AM and PFC. Acute psychogenic stress inhibited CAT activity in the AM and PFC, and increased Mn-SOD activity in the PFC. These results demonstrate that different responses can be elicited by the same stressor in two separate brain regions involved in processing emotional stimuli, and that changes in specific antioxidant enzymatic responses can be seen with exposure to acute psychogenic stress.

English

Recent increase of hormonal disorders in human may be correlated to the increased exposure to electromagnetic fields produced by various instruments, including cell phones. Because of its position in the body, thyroid gland is one of the organs most likely to be exposed to cell phone radiation. The aim of this study was to assess the adverse effects of cell phone radiation along with the protective effects of garlic on pituitary thyroid hormones and histology of thyroid gland in rats. Five groups of rats were used: control, sham (exposed to 900 MHz wavelength), experimental 1 (receiving garlic extract), and experimental 2 and 3 (receiving both extract and microwaves). After a month, rats were weighed and serum levels of TSH, T4 and T3 were measured using ELISA kits. Thyroid glands were also removed and their probable histological changes were studied. The mean body weight in the sham group showed a statistically significant decrease compared to the control group, whereas, ‌an increase was seen in the experimental group 3 compared with sham (P<0.05). In addition, the concentrations of T4 and T3 hormones were lowered while TSH increased significantly in all groups compared to the control. Furthermore, histological examination of thyroid revealed a reduction in the number of cubic cells and disorder among them, as well as a reduction in the amount of follicular fluid and follicular diameter in groups exposed to radiation and received garlic extract. Although, microwaves can cause weight lost, presence of allicin and vitamins A and B in garlic can compensate some of this weight lost. In addition, both microwaves and garlic extract have a considerable effect on thyroid gland, reflected both in its secretion and in its morphology. These changes might be attributed to induction of heat and non-specific stresses, alterations of cortisol level, production of ROS and activities of various enzymes. However, some of these overlapping effects are synergistic and others are antagonistic, and thus, garlic consumption is not always beneficial in reducing deleterious effects of cell phones.   Key words: Electromagnetic radiation, cell phone, garlic, thyroid hormone.

Comparison of Primary and Secondary Rat Astrocyte Cultures Regarding Glucose and Glutathione Metabolism and the Accumulation of Iron Oxide Nanoparticles

Astrocyte-rich primary cultures (APCs) are frequently used as a model system for the investigation of properties of brain astrocytes. However, as APCs contain a substantial number of microglial and oligodendroglial cells, biochemical parameters determined for such cultures may at least in part reflect also the presence of the contaminating cell types. To lower the potential contributions of microglial and oligodendroglial cells on properties of the astrocytes in APCs we prepared rat astrocyte-rich secondary cultures (ASCs) by subculturing of APCs and compared these ASCs with APCs regarding basal metabolic parameters, specific enzyme activities and the accumulation of iron oxide nanoparticles. Immunocytochemical characterization revealed that ASCs contained only minute amounts of microglial and oligodendroglial cells. ASCs and APCs did not significantly differ in their specific glucose consumption and lactate production rates, in their specific iron and glutathione contents, in their specific activities of various enzymes involved in glucose and glutathione metabolism nor in their accumulation of iron oxide nanoparticles. Thus, the absence or presence of some contaminating microglial and oligodendroglial cells appears not to substantially modulate the investigated metabolic parameters of astrocyte cultures.

Evaluation of antioxidant, antimutagenic, and lipid peroxidation inhibitory activities of selected fractions of Holarrhena floribunda (G. Don) leaves.

Exposure to environmental pollutants often leads to an upsurge in the production of reactive oxygen species (ROS). ROS oxidize cellular fatty acids to produce lipid peroxyl radicals, subsequently transformed into lipid peroxides, which decrease membrane fluidity and increase the activity of various enzymes implicated in degenerative diseases and cancer formation. Edible plants that contain exogenous compounds like curcumeroid, β-carotene, turmeric, and so on, protect the aerobic cells from oxidation of free radicals. This study thus evaluates antioxidant and antimutagenic activities of ethyl acetate, aqueous and methanolic fractions of Holarrhena floribunda leaves. Inhibitory activities of the ethyl acetate fraction on Fe(2+)-induced lipid peroxidation in hen egg yolk; rat liver and brain tissues were also evaluated. The Allium cepa root assay was used to evaluate antimutagenic activity. Results showed that the ethyl acetate scavenged DPPH, OH•, and •O2(-) much stronger than other fractions, as evidenced by its lowest respective IC50 values. All the fractions displayed antimutagenic activities against cyclophosphamide-induced chromosomal aberrations. Likewise, all the fractions induced a reduction in mitotic index, a hallmark of cytotoxicity in the root meristem of Allium cepa. The decrease in mitotic index was most profound for the ethyl acetate fraction, which also demonstrated a significant lipid peroxidation inhibitory activity in the liver and brain homogenates, but not in egg yolk, compared with the ascorbic acid standard. In general, the results suggest that the ethyl acetate fraction might contain beneficial phytochemicals that should be explored as novel candidates for preclinical drug development.

가열온도, 가열시간 및 부형제의 첨가량이 도축 반추위 내용물의 자일란, 셀룰로오스 및 전분 분해효소 활성에 미치는 영향

본 연구는 도축장에서 폐기되는 도축 반추위 내용물을 사일리지 혹은 TMR (total mixed ration) 사료 첨가용 효소제로 개발하기 위한 목적으로 수행되었다. 도축 반추위 내용물에는 상당한 수분이 함유되어 있어, 적절한 건조과정을 거치지 않고서는 그 활용이 원활하지 않다. 그러나 효소는 열에 민감한 단백질로 구성되어 있기 때문에 적절한 건조 조건의 개발이 필요하다. 본 연구에서는 통계적 방법을 이용하여 가열온도(60, 75, <TEX>$90^{\circ}C$</TEX>), 가열시간(12, 30, 48 시간) 및 부형제의 비율(12, 22.5, 33%)이 도축 반추위 내용물에 함유된 다양한 효소활성에 미치는 효과를 분석하였다. 총 3가지 효소, xylan 분해효소, 셀룰로오스 분해효소 및 전분 분해효소를 검토하였고, 각 효소활성들에 대한 각 요인들의 효과가 매우 다양하게 나타났다(p<0.05). 셀룰로오스 분해효소와 전분 분해효소의 활성은 가열온도가 증가함에 따라 감소하였으며(p<0.05), xylan 분해해소는 열에 대한 안전성이 다른 효소들에 비하여 우수하였다. 자일란, 셀룰로오스, 전분 분해효소를 증가시키는 적정 부형제의 비율은 22.5, 12 그리고 33%로 나타났다. 비록 3가지 효소들의 제형화에 있어 공통적으로 적용될 수 있는 최적점을 도출하지는 못하였으나, 본 연구결과에서 얻어진 효소들의 반응 값들을 이용하여 목적하는 효소에 따라서 다양한 방법으로 적용이 가능할 것으로 판단된다. This study was conducted in order to develop slaughterhouse rumen content (SRC) as a potential feed additive. The moisture content of SRC can reach 80%, and therefore an appropriate dewatering process is required before it can be used. In this study, the effects of heating temperature, heating time, and filler content during the dewatering process on the activity of various enzymes in SRC were investigated. The Box-Behnken experimental design was employed, involving a total of 45 experimental runs, consisting of three variables (heating time, heating temperature, and filler content) with three levels per variable (12, 30 and 48 hr; 60, 75 and <TEX>$90^{\circ}C$</TEX>; 12, 22.5 and 33% for heating time, heating temperature, and filler content, respectively). For enzyme activities, xylanase, cellulase, and amylase were examined, and the results were subjected to an analysis of variance. Heating time, heating temperature and filler content had significant effects on the activity of each enzyme (p<0.05). Cellulase and amylase activities decreased (p<0.05) at elevated heating temperatures, whereas xylanase was reasonably stable around <TEX>$90^{\circ}C$</TEX>. The activities of all enzymes decreased (p<0.05) with increased heating time. Optimum filler contents for xylanase, cellulase, and amylase activities were 22.5, 12 and 33%, respectively. However, optimum conditions for all variables that simultaneously maximize the activity of all three enzymes could not be ascertained in this study. Nevertheless, the results from the current study can be useful as basic information for the development of SRC as a feed additive enriched with improved major enzymes for livestock feed digestion.

Soil enzymatic activity in the impact zone of sulphur compounds emission

Activity of various enzymes is used for the assessing the effect of anthropogenic fsctors on soil microbiological activity. Dehydrogenase activity is considered a measurement of total soil microbiological activity. A crucial element of anthropogenic transformations of the natural environment is acid soil degradation caused by the storage of acid forming substances, such as eg elementary sulphur and atmospheric pollution with its compounds. In Poland the largest areas strongly polluted with sulphur are situated in the Tarnobrzeg Sulphur Basin, where pulverized sulphur (transported by wind from the minefields and places of storage) and the products of its oxidation, such as acid rains or dry deposit have found its way not only to the soils covering the mining area but also to the soils beyond the boundary of the mine area. The research aimed to assess the influence of pollution emitted during the thirty-year-long exploitation of sulphur deposits on the microbiological activity of soils situated in the vicinity of Grzybow Sulphur Mine. The investigated soils taken from the areas situated in neighbouring of mine are characterized by low, as a rule below 1, level of degydrogenase activity and acid soil reaction and generally a high share of sulphate sulphur in the total sulphur content. The conducted assessment of the activity of studied enzymes shows, that the pollution of the soil environment around the mine remains on the level which may pose a threat to living organisms. The cause of the considerable decrease of the level of dehydrogenase activity of studied soils may be their acid reaction which is the result of long-term emission of sulphur compounds. In the surface soil layer sulphur is oxidized to sulphuric acid, which cause a strong soil acidification.

Effects of Single Exposure of Sodium Fluoride on Lipid Peroxidation and Antioxidant Enzymes in Salivary Glands of Rats

Many studies suggest that fluoride exposure can inhibit the activity of various enzymes and can generate free radicals, which interfere with antioxidant defence mechanisms in living systems. To further the understanding of this issue, this present study examined the effects of low-dose fluoride treatment on the activity of enzymatic antioxidant superoxide dismutase (SOD) and catalase (CAT), as well as the levels of lipid peroxidation (LPO) in the parotid (PA) and submandibular (SM) salivary glands of rats. Rats were injected with a single dose of sodium fluoride (NaF) (15 mg F−/kg b.w.) then euthanized at various time intervals up to 24 hours (h) following exposure. NaF exposure did not cause significant differences in SOD or CAT activity or LPO levels in PA glands compared to control. Conversely, SM glands presented increased SOD activity after 3 h and decreased SOD activity after 1, 12, and 24 h, while LPO was increased after 6, 12, and 24 h of the NaF injection. There were no significant differences in the CAT activity in the groups studied. Our results demonstrated that NaF intoxication caused oxidative stress in salivary glands few hours after administration. These changes were more pronounced in SM than in PA gland.

Modulation of Antioxidant Enzymatic Activities by Certain Antiepileptic Drugs (Valproic Acid, Oxcarbazepine, and Topiramate): Evidence in Humans and Experimental Models

It is estimated that at least 100 million people worldwide will suffer from epilepsy at some point in their lives. This neurological disorder induces brain death due to the excessive liberation of glutamate, which activates the postsynaptic N-methyl-D-aspartic acid (NMDA) receptors, which in turn cause the reuptake of intracellular calcium (excitotoxicity). This excitotoxicity elicits a series of events leading to nitric oxide synthase (NOS) activation and the generation of reactive oxygen species (ROS). Several studies in experimental models and in humans have demonstrated that certain antiepileptic drugs (AEDs) exhibit antioxidant effects by modulating the activity of various enzymes associated with this type of stress. Considering the above-mentioned data, we aimed to compile evidence elucidating how AEDs such as valproic acid (VPA), oxcarbazepine (OXC), and topiramate (TPM) modulate oxidative stress.

Sumoylation in neurodegenerative diseases.

The yeast SUMO (small ubiquitin-like modifier) orthologue SMT3 was initially discovered in a genetic suppressors screen for the centromeric protein Mif2 (Meluh and Koshland in Mol Bio Cell 6:793-807, 1). Later, it turned out that the homologous mammalian proteins SUMO1 to SUMO4 are reversible protein modifiers that can form isopeptide bonds with lysine residues of respective target proteins (Mahajan et al. in Cell 88:97-107, 2). This was the discovery of a post-translational modification called sumoylation, which enzymatically resembles ubiquitination. However, very soon it became clear that SUMO attachments served a far more diverse role than ubiquitination. Meanwhile, numerous cellular processes are known to be subject to the impact of SUMO modification, including transcription, protein targeting, protein solubility, apoptosis or activity of various enzymes. In many instances, SUMO proteins create new protein interaction surfaces or block existing interaction domains (Geiss-Friedlander and Melchior in Nat Rev in Mol Cell Biol 8:947-956, 3). For the past few years, sumoylation attracted increasing attention as a versatile regulator of toxic protein properties in neurodegenerative diseases. In this review, we summarize the growing knowledge about the involvement of sumoylation in neurodegeneration, and discuss the underlying molecular principles affected by this multifaceted and intriguing post-translational modification.

Abstract 164: High throughput homogenous bioluminescent assays for monitoring the concentrations of AMP, ADP and ATP

Abstract Adenine nucleotides are major determinants of the energy status of the cell and thus any modulation of their cellular concentration has significant consequences to cellular metabolism, cellular growth and cell death. ATP generating enzymes are usually involved in anabolic processes while ATP consuming enzymes are involved in catabolite processes. We have developed biochemical assays that monitor the concentrations of ATP, ADP and AMP in a biochemical reaction. For instance ATP depletion dependent assays and ADP generating assays monitor the activity of kinases and ATPases. These universal assays can measure the activity of various enzymes with no modification of the native substrate and the ability to use diverse substrates such as proteins, peptides, lipids, sugars, etc. The AMP generating reactions such as ubiquitin ligases, aa aminoacyl t-RNA synthetases, DNA ligases, cAMP-dependent phosphodiesterases, etc. can be also monitored with high sensitivity and reproducibility. We will show data using these various technologies in monitoring the various adenine nucleotide concentrations in biochemical reactions. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 164. doi:1538-7445.AM2012-164

Agaricus blazei Murill as an efficient hepatoprotective and antioxidant agent against CCl4-induced liver injury in rats

Agaricus blazei Murill is one of the very popular edible medicinal mushrooms. The present study investigated the protective effect of this biologically active mushroom on the tissue peroxidative damage and abnormal antioxidant levels in carbon tetrachloride induced hepatotoxicity in male albino rats. Male albino rats of Sprague–Dawley strain weighting (120–150g) were categorized into five groups. The first group served as the normal control, the second and the third groups were treated with Agaricus blazei Mushroom extract and carbon tetrachloride dose, respectively. Fourth group (protective group) was first treated with Agaricus blazei Mushroom extract followed by carbon tetrachloride treatment and fifth (therapeutic group) with carbon tetrachloride first followed by Agaricus blazei Mushroom treatment. The wet fruiting bodies of mushroom Agaricus blazei Murill, crushed and suspended in distilled water was administered orally to the treated groups of male albino rats. The activities of various enzymes (aspartate and alanine transaminase, lactate dehydrogenase, glutathione reductase), levels of non-enzymatic antioxidants (glutathione, vitamin C, vitamin E) and level of lipid peroxidation (malondialdehyde) were determined in the serum of all the experimental animals. Decrease in all the enzymes and non-enzymatic antioxidant, along with an increase in the lipid peroxidative index (malondialdehyde) was found in all the carbon tetrachloride treated rats as compared with normal controls. Also increase level of non-enzymatic antioxidant along with the decrease level in malondialdehyde was found in all experimental animals which were treated with Agaricus blazei Mushroom extract as compared with normal controls. The findings indicate that the extract of Agaricus blazei Murill can protect the liver against carbon tetrachloride induced oxidative damage in rats and is an efficient hepatoprotective and antioxidant agent against carbon tetrachloride induced liver injury.

Ecotoxicity of silver nanoparticles on earthworm Eisenia fetida: responses of the antioxidant system, acid phosphatase and ATPase

Ecotoxicity of nanoparticles has received growing attention in recent years. This study investigated the influence of silver nanoparticles (Ag-NP) on earthworm Eisenia fetida. The experiment was performed with five test groups: control (without Ag-NP), 10 nm Ag-NP groups (20, 100 or 500 mg kg−1) and positive control (787 mg kg−1 AgNO3). After 14-day acute exposure, activities of various enzymes, including glutathione S-transferase (GST), glutathione reductase (GR), acid phosphatase (AP), and Na+, K+-ATPase were determined. Effects of Ag-NP with different sizes (10 and 80 nm) were also tested. Data showed that the activity of GR was significantly lower at 500 mg kg−1. The activities of AP and Na+, K+-ATPase were inhibited following the increase of Ag-NP concentration. When treated with Ag-NP with different sizes, activities of AP and Na+, K+-ATPase of the 10 nm group were significantly lower than the control group, but those of the 80 nm group were similar to the control group. Data indicate that Ag-NP may be harmful to the earthworm E. fetida at 500 mg kg−1, and the toxicity of Ag-NP with 10 nm size is greater than 80 nm. In addition, AP and Na+, K+-ATPase are sensitive biomakers to the effects of Ag-NP.

Dietary moderately oxidized oil activates the Nrf2 signaling pathway in the liver of pigs

BackgroundPrevious studies have shown that administration of oxidized oils increases gene expression and activities of various enzymes involved in xenobiotic metabolism and stress response in the liver of rats and guinea pigs. As these genes are controlled by nuclear factor erythroid-derived 2-like 2 (Nrf2), we investigated the hypothesis that feeding of oxidized fats causes an activation of that transcription factor in the liver which in turn activates the expression of antioxidant, cytoprotective and detoxifying genes.MethodsTwenty four crossbred pigs were allocated to two groups of 12 pigs each and fed nutritionally adequate diets with either fresh rapeseed oil (fresh fat group) or oxidized rapeseed oil prepared by heating at a temperature of 175°C for 72 h (oxidized fat group).ResultsAfter 29 days of feeding, pigs of the oxidized fat group had a markedly increased nuclear concentration of the transcription factor Nrf2 and a higher activity of cellular superoxide dismutase and T4-UDP glucuronosyltransferase in liver than the fresh fat group (P < 0.05). In addition, transcript levels of antioxidant and phase II genes in liver, like superoxide dismutase 1, heme oxygenase 1, glutathione peroxidase 1, thioredoxin reductase 1, microsomal glutathione-S-transferase 1, UDP glucuronosyltransferase 1A1 and NAD(P)H:quinone oxidoreductase 1 in the liver were higher in the oxidized fat group than in the fresh fat group (P < 0.05). Moreover, pigs of the oxidized fat group had an increased hepatic nuclear concentration of the transcription factor NF-κB which is also an important transcription factor mediating cellular stress response.ConclusionThe present study shows for the first time that administration of an oxidized fat activates the Nrf2 in the liver of pigs which likely reflects an adaptive mechanism to prevent cellular oxidative damage. Activation of the NF-κB pathway might also contribute to this effect of oxidized fat.

Studies on the protective effect of flaxseed oil on cisplatin-induced hepatotoxicity

Cisplatin (CP) is known as one of the most potent chemotherapeutic antitumor drugs. The tissue-specific toxicity of CP in the kidneys is well documented. However, at higher doses less common toxic effects such as hepatotoxicity may arise. Since CP remains one of the most effective antineoplastic drug used in chemotherapy, strategies to protect tissues against CP toxicity are of clinical interest. Recently, ω-3 polyunsaturated fatty acids (PUFAs) from certain plants/seeds notably flaxseed have shown numerous health benefits. In view of this, the present study investigates the protective effect of flaxseed oil (FXO) on CP-induced damage in liver. Rats were pre-fed normal diet and the diet rich in FXO for 10 days and then a single dose of CP (6 mg/kg body weight) was administered intraperitoneally while still on diet. Serum/urine parameters, enzymes of carbohydrate metabolism and oxidative stress were analyzed. CP caused perturbation of the antioxidant defense as reflected by the decrease in the activities of catalase, superoxide dismutase and glutathione peroxidase. Further the activities of various enzymes involved in glycolysis, tricarboxylic acid cycle, gluconeogenesis and hexose monophosphate shunt pathways were determined and were found to be differentially altered by CP treatment. However, these alterations were ameliorated in CP-treated rats fed on FXO. Present results show that dietary supplementation of FXO in CP-treated rats ameliorated CP-induced hepatotoxic and other deleterious effects due to its intrinsic biochemical/antioxidant properties.