bluuebunny/crossref_metadata_2025_split huggingface dataset:
Generation of lipid peroxyl radicals from edible oils and their biological activities: A need for consideration for anti‐radical components and purification processing
Authors: Kanazawa Ayako , Sawa Tomohiro , Akaike Takaaki , Morimura Shigeru , Kida Kenji , Maeda Hiroshi 
Published: December 2008

AbstractLipid hydroperoxides (LOOH or oxidized oils) are known as unfavorable food components. Molecular details of the fate and mechanisms of LOOH to exert adverse effects in vivo are, however, little understood. In the present study, we demonstrated that LOOH generated alkylperoxyl radical (LOO.) after reaction with various heme compounds such as myoglobin, cytochrome c, hemin, hematin, etc., but little formation of other radical species was noticed such as L. or LO.. It was also shown that LOO. thus formed exhibits cytotoxicity and caused DNA damages including strand breakage and abasic site formation. This highly toxic LOO. is effectively scavenged by hot water extracts of vegetable (soup), flavonoids, polyphenols as well as tocopherols. Another important finding is that crude vegetable oils are rich in potent‐LOO. scavenging activity, which exhibits potent anti‐oxidant activity as well; whereas highly purified oils are scanty in such components and LOO. scavenging activity. These findings imply that a considerate processing in the refining of oils should be needed to retain such potent endogenous anti‐oxidative radical scavenging‐components.
A model for Sec incorporation with the regions upstream of the UGA Sec codon to play a key role
Authors: Goto Chiharu , Osaka Takashi , Mizutani Takaharu 
Published: December 2008

AbstractFor eukaryotic selenoprotein mRNAs, it has been proposed that the SECIS element in the 3′‐UTR is required for recognition of UGA as a Sec codon. Some proteins which bind to SECIS (SBP) have been reported. However, it is not clear how the SECIS element in the 3′‐UTR can mediate Sec insertion far at the in‐frame UGA Sec codons. The idea that there must be a signal near the UGA Sec codon is still being considered. Therefore, we searched for a protein which binds to an RNA sequence surrounding the UGA Sec codon on human GPx mRNA. We found a protein, prepared from bovine brain microsomes, which strongly bound to the RNA fragment upstream of the UGA Sec codon but not to the RNA sequence downstream of the UGA codon. This protein also bound to the SECIS sequence in the 3′‐UTR of human GPx, and this binding to SECIS was competed with the RNA fragment upstream of the UGA Sec codon. We also obtained the similar results with the RNA fragments of type I iodothyronine 5′‐deiodinase (5′DI) mRNAs. Comparison of such RNA fragments with SECIS fragments revealed similarities in the region upstream of the in‐frame UGA Sec codon of several Se‐protein mRNAs. The study thus favoures a novel model of Sec incorporation at the UGA Sec codon that involves the regions upstream of the UGA codon of mRNAs of mammalian selenoproteins. This model explains that the stem‐loop structure covering the UGA codon is recognized by SBP and how the UGA Sec codon escapes from attack by eRF.
An extended Escherichia coli “Selenocysteine Insertion Sequence” (SECIS) as a multifunctional RNA structure
Authors: Engelberg‐Kulka Hanna , Liu Zesheng , Li Chuang , Reches Myriam 
Published: December 2008

AbstractThe genetic code, once thought to be rigid, has been found to permit several alternatives in its reading. Interesting alternative relates to the function of the UGA codon. Usually, it acts as a stop codon, but it can also direct the incorporation of the amino acid selenocysteine into a polypeptide. UGA‐directed selenocysteine incorporation requires a cis‐acting mRNA element called the “selenocysteine insertion sequence” (SECIS) that can form a stem‐loop RNA structure. Here we discuss our investigation on the E. coli SECIS. This includes the follows: 1) The nature of the minimal E. coli SECIS. We found that in E. coli only the upper‐stem and loop of 17 nucleotides of the SECIS is necessary for selenocysteine incorporation on the condition that it is located in the proper distance from the UGA [34]; 2) The upper stem and loop structure carries a bulged U residue that is required for selenocysteine incorporation [34] because of its interaction with SelB; and 3) We described an extended fdhF SECIS that includes the information for an additional function: The prevention of UGA readthrough under conditions of selenium deficiency [35]. This information is contained in a short mRNA region consisting of a single C residue adjacent to the UGA on its downstream side, and an additional segment consisting of the six nucleotides immediately upstream from it. These two regions act independently and additively and probably through different mechanisms. The single C residue acts as itself; the upstream region acts at the level of the two amino acids, arginine and valine, for which it codes. These two codons at the 5′ side of the UGA correspond to the ribosomal E and P sites. Finally, we present a model for the E. coli fdhF SECIS as a multifunctional RNA structure containing three functional elements. Depending on the availability of selenium the SECIS enables one of two alternatives for the translational machinery: Either selenocysteine incorporation into a polypeptide or termination of the polypeptide chain.
Plasma selenium in specific and non‐specific forms
Authors: Burk Raymond F. , Hill Kristina E. , Motley Amy K. 
Published: December 2008

AbstractSelenium is present in plasma and tissues in specific and non‐specific forms. The experiments reported here were carried out to clarify some factors that affect these forms of the element in plasma. A selenium‐replete human subject was given 400 μg of selenium daily for 28 days as selenomethionine and, in a separate experiment, as selenate. The selenomethionine raised plasma and albumin selenium concentrations. Selenate did neither. The molar ratio of methionine to selenium in albumin was approximately 8000 under basal and selenate‐supplemented conditions but 2800 after selenomethionine supplementation. This demonstrates that selenium from selenomethionine, but not selenium from selenate, can be incorporated into albumin, presumably as selenomethionine in the methionine pool. Selenocysteine incorporation into albumin was studied in rats using 75Se‐selenocysteine. No evidence was obtained for incorporation of 75Se into albumin after exogenous administration or endogenous synthesis of 75Se‐selenocysteine. Thus, selenocysteine does not appear to be incorporated non‐specifically into proteins as is selenomethionine. These findings are in support of selenomethionine being a non‐specific form of selenium that is metabolized as a constituent of the methionine pool and is unaffected by specific selenium metabolic processes. No evidence was found for non‐specific incorporation of selenium into plasma proteins when it was administered as selenate or as selenocysteine. These forms of the element appear to be metabolized by specific selenium metabolic processes.
Coenzyme Q differentially modulates phospholipid hydroperoxide glutathione peroxidase gene expression and free radicals production in malignant and non‐malignant prostate cells
Authors: Quiles J. L. , Farquharson A. J. , Ramírez‐Tortosa M. C. , Grant I. , Milne L. , Huertas J. R. , Battino M. , Mataix J. , Wahle K. W. J. 
Published: December 2008

AbstractThe aim of this study was to investigate the role of coenzyme Q on the mRNA abundance of PHGPx and the reactive oxygen species (ROS) production in two different cell lines from human prostate, a line of non cancer cells (PNT2) and a line of cancer cells (PC3). Results showed that malignant cells markedly differ in their response to coenzyme Q compared to non‐malignant cells, with no changes in PHGPx expression and greater ROS production. Furthermore coenzyme Q supplementation significantly lowered cell growth of the PC3 cancer line without affecting the PNT2. If these results are confirmed with additional experiments, it could represent a novel and interesting approach on the biomedical use of coenzyme Q10 in cancer therapy.
ADP‐ and oligomycin‐sensitive redox behavior of F0 b thiol in ATPsynthase depends on neighbored primary structure: Investigations using 14‐C‐labeled alpha lipoic acid
Authors: Dünschede Fritz , Zwicker Klaus , Ackermann Hanns , Zimmer Guido 
Published: December 2008

AbstractPurified ATPsynthase of bovine heart mitochondria has been analyzed for its mobility and reactivity of oligomycin‐sensitive sulfhydryl regions in presence of the substrate ADP and oligomycin. Labeling of thiol groups at the hydrophobic F0 region of the ATPsynthase was increased in the enzyme initially treated with SDS, N‐ethylmaleimide and dithiothreitol (modified enzyme). After dialysis or gel permeation the ATPsynthase was treated with [14C] alpha lipoic acid at a molar ratio of 35‐85/1 (lipoic acid/ATPsynthase) corresponding to 4‐8.6 nmol/mg protein. Under these conditions, ATPase activity of the native enzyme was significantly decreased. After preincubation with ADP, PAGE of the native, [14C] labeled enzyme revealed an increase of radioactivity at a region of 25 kDa deduced to Cys 197 of subunit b. In the modified enzyme the increase in radioactivity was found at 10 kDa. In this context, the sequence Lys‐Cys‐Ile around Cys 197 of subunit b suggests excessive reactivity of this thiol, as well as ready reversibility by ‐SH‐S‐S‐ interchange. Therefore, previously observed reaction by thiol reagents and antioxidants from outside the mitochondrion can be interpreted with Cys 197 of F0 b. It accounts for sulfhydryl unmasked by binding of ADP at F1.
Manganese alters mitochodrial integrity in the hearts of swine marginally deficient in magnesium
Authors: Miller Kevin B. , Newman Samuel M. , Caton Joel S. , Finley John W. 
Published: December 2008

AbstractIt was previously reported that pigs marginally deficient in magnesium (Mg) and fed diets high in manganese (Mn) died suddenly with signs of sudden cardiac death. Manganese, which has properties similar to Mg, may exacerbate Mg‐deficiency and be accumulated by mitochondria resulting in ultrastructural damage. The objective of this study was to determine whether deaths of the type previously observed were mediated by adverse interactions of Mn and Mg resulting in ultrastructural damage to the myocardium, alterations in electrocardiographic recordings and tissue retention of Mn, Mg and calcium (Ca). Forty‐eight pigs were fed one of six diets in a 2 × 3 factorial arrangement of Mg (100 or 1000 mg Mg/kg) and Mn (5, 50 or 500 mg Mn/kg) for 8 weeks. Left ventricle muscle samples were collected for examination by transmission electron microscopy. No differences in heart muscle ultrastructure were observed between pigs fed low and adequate dietary Mg. However, marked myocardial necrosis and mitochondrial swelling were observed in pigs fed high dietary Mn when combined with low Mg. Feeding low dietary Mg elevated minimum (P < 0.01), maximum (P < 0.05) and average (P < 0.001) heart rates. Low dietary Mg resulted in a 55% probability of a ventricular beat being recorded (P = 0.05) and lower Mg (P < 0.02) and Ca (P < 0.04) contents in heart atria and ventricles. These results suggest that high Mn, when fed in combination with low Mg, disrupts mitochondrial ultrastructure and is associated with the sudden deaths previously reported.
Redox regulation of ascorbic acid transport: Role of transporter and intracellular sulfhydryls
Authors: May James M. , Qu Zhi‐chao 
Published: December 2008

AbstractAscorbic acid is one of the most sensitive cellular defenses against oxidant damage. However, it requires a sodium‐ and energy‐dependent transporter to enter cells against a concentration gradient. To test the hypothesis that ascorbate transport is sensitive to redox stress, we studied changes in transport of the vitamin in response to sulfhydryl modification of the protein and to GSH depletion in cultured endothelial cells. Transport of ascorbic acid, measured as the uptake of radiolabeled ascorbate, was inhibited by the membrane‐impermeant sulfhydryl reagents thorin, p‐chloromercuribenzene sulfonic acid, and 5,5′‐dithiobis‐(2‐nitrobenzoic acid) in a dose‐dependent manner without significant depletion of intracellular GSH. Sulfhydryl reagents capable of penetrating the plasma membrane, including phenylarsine oxide, p‐chloromercuribenzoic acid, and N‐ethylmaleimide, inhibited transport and lowered cellular GSH. Diamide, which induces disulfide formation, increased ascorbate transport over a narrow concentration range under conditions in which GSH was not depleted. On the other hand, specific depletion of intracellular GSH by several different mechanisms did inhibit transport. Together, these results suggest that the ascorbate transporter is sensitive to redox modulation. This relates in part to sulfhydryl groups exposed on the exofacial ascorbate transporter, and to sulfhydryl groups that are sensitive to changes in the redox state of intracellular GSH.
Effect of high phosphorus diet on phosphorus metabolism in parathyroidectomized rats
Authors: Katsumata Shin‐Ichi , Masuyama Ritsuko , Koshihara Moyuru , Matsuzaki Hiroshi , Uehara Mariko , Suzuki Kazuharu 
Published: December 2008

AbstractTo determine the parathyroid hormone (PTH) action on kidney and bone by high phosphorus (P) diet, this study investigated PTH/PTH‐related peptide (PTHrP) receptor mRNA expression in 6‐week‐old parathyroidectomized (PTX) rats received constant amount of PTH. To maintain serum PTH levels equally to sham operated rats, PTX rats were constantly exposed to rPTH (1–34) and fed a control diet (0.3% P) and a high P diet (1.2% P) for 7 days, respectively. There were no significant differences in serum PTH (1–34) concentration in rats fed the control diet. In sham groups, serum PTH concentrations, both (1–84) and (1–34) fragments, were increased in rats fed the high P diet than in rats fed the control diet. Urinary excretions of P and C‐terminal telopeptides of type I collagen were significantly increased in both PTX and sham rats by the high P diet. PTH/PTHrP receptor mRNA expression in kidney and femur was not changed in both PTX and sham rats by the high P diet. In conclusion, high P diet did not change PTH action in PTX rats and increased urinary excretion of P and bone resorption regardless of PTH action.
Cancer prevention by antioxidants
Authors: Nishino Hoyoku , Tokuda Harukuni , Satomi Yoshiko , Masuda Mitsuharu , Osaka Yasuhito , Yogosawa Shingo , Wada Saeri , Mou Xiao Yang , Takayasu Junko , Murakoshi Michiaki , Jinnno Kenji , Yano Masamichi 
Published: December 2008

AbstractVarious antioxidants in foods, such as phenolic compounds and carotenoids, were proven to have anticarcinogenic activity.In the case of carotenoids, the mixture of them was found to be very effective. In fact, the development of hepatoma in the high risk group of liver cancer, was significantly suppressed by the treatment with natural carotenoids mixture.The role of nitric oxide (NO) in carcinogenesis has been pointed out, since large quantity of NO has been detected in cancer tissues, and the expression of inducible NO synthase (iNOS) was found to correlate with tumor growth and metastasis. Recently, we found that NO possessed tumor initiating activity in mouse skin carcinogenesis. It has been suggested that some parts of pathological effects induced by NO may depend on peroxynitrite, an active metabolite of NO. Thus, we accessed the tumor initiating activity of peroxynitrite, and found that treatment with peroxynitrite (initiator) plus TPA (promoter) resulted in the formation of skin tumors. Under this experimental condition, it has been proven that natural antioxidants, such as curcumin and nobiletin, showed anti‐tumor initiating effect. In the case of nobiletin, suppressive effect on iNOS induction has also been demonstrated. It is of interest that suppression of iNOS induction was also observed in phytoene synthase transgenic mouse. After administration of glycerol (a lung tumor promoter), lower induction of iNOS gene was observed in lung of the phytoene producing mice, comparing with that of control mice.Combinational use of various kinds of antioxidants distributed in foods, e.g., mixture of carotenoids and flavonoids, seems to be effective methods for cancer prevention.
18O‐Labeled lipid hydroperoxides and HPLC coupled to mass spectrometry as valuable tools for studying the generation of singlet oxygen in biological system
Authors: Miyamoto Sayuri , Martinez Glaucia R. , Martins Ana Paula B. , Medeiros Marisa H. G. , Mascio Paolo Di 
Published: December 2008

AbstractDecomposition of lipid hydroperoxides (LOOH) is known to generate toxic products capable to induce tissue injury. We have recently confirmed that decomposition of LOOH into peroxyl radicals is a potential source of singlet oxygen (1O2) in biological system. Using 18O‐labeled linoleic acid hydroperoxide (LA18O18OH) in the presence of Ce4+ or Fe+2, we observed the formation of 18O‐labeled 1O2 (18[1O2]) by chemical trapping of 1O2 with 9,10‐diphenylanthracene (DPA) and detecting the corresponding 18O‐labeled DPA endoperoxide (DPA18O18O) by HPLC coupled to tandem mass spectrometry (HPLC‐MS/MS). 18O‐Labeled alcohol and ketone were also detected providing further evidence for the generation of 1O2by the Russell mechanism. Similarly the reaction of LA18O18OH with peroxynitrite also generated18[1O2].In conclusion, these results indicates that the use of 18O‐labeled LOOH associated with HPLC‐MS/MS can be an useful tool to clarify mechanistic features involved in the reaction of LOOH in biological media.
Liquid‐liquid extraction of α‐lactalbumin using reverse micellar organic solvent
Authors: Naoe Kazumitsu , Noda Kazuki , Konishi Taiji , Kawagoe Mikio , Imai Masanao 
Published: December 2008

AbstractThe liquid‐liquid extraction of α‐lactalbumin based on reverse micellar organic solvents was investigated. Forward extraction of the protein in the reverse micellar organic phase from aqueous feed solutions was strongly dependent on the initial pH of the feed solution and the complete forward extraction of 0.03 mM α‐lactalbumin was successfully achieved at pH 6.0. The forward extraction percentage steeply decreased with increasing KCl concentration, while in the NaCl system the forward extraction was independent on the salt concentration below 1 M. From the circular dichroic measurement, higher order structure of the recovered α‐lactalbumin through the extraction process was well preserved.
Induction of apoptosis in a human lymphoma cell line by hydrophobic peptide fraction separated from anchovy sauce
Authors: Lee Young Gon , Lee Ki Won , Kim Ji Yeon , Kim Kyoung Heon , Lee Hyong Joo 
Published: December 2008

AbstractPeptide fractions showing anticancer activity were isolated from anchovy sauce, and their abilities to induce apoptosis in a human lymphoma cell (U937) were determined by biochemical and flow cytometric methods. The butanol extract (fraction Aob) from the desalted hydrophobic peptide fraction (Ao) separated from anchovy sauce by HP‐20 adsorption chromatography was found to possess strong antiproliferative activity against U937 by inducing apoptosis. Treatment of U937 with Aob resulted in sub‐G1 peak representing apoptosis in the cell cycle analysis, and apoptotic DNA fragmentation. Antiproliferative activity of the peptide fraction further purified successively by silica gel chromatography, TLC, and reversed‐phase HPLC increased proportionally with the purification fold. The peptide fraction having antiproliferative activity was found to be composed of Ala and Phe, and its molecular weight was estimated to be 440.9 Da.
Caseinophosphopeptides and their cell modulating potential
Authors: Hartmann R. , Meisel H. 
Published: December 2008

AbstractIn the context of the EU research project FAIR‐CT 98–3077, studies were carried out to investigate caseinophosphopeptides (CPP) as potential ingredients for functional food and pharmaceutical applications.CPP preparations were produced by enrichment of CPP from hydrolytic casein digests. Enzyme preparations used for hydrolysis were PTN 3.0 S, Alcalase, Bioprotease P conc, Proteinase DS. Cytochemical studies were carried out to examine the cytotoxic potential or cell modulating activities of CPP using human cancer cell lines (HL‐60, Caco‐2) and non‐malignant polymorphonuclear leukocytes (PML) from oral cavity. PML cells isolated by magnetic cell sorting using CD‐15‐antibody‐labelled paramagnetic beads were used for the first time for testing food‐derived peptides. Cell activity was measured by formazan dye formation. Effects on enterocytic differentiation properties of Caco‐2 cells were examined by transepithelial membrane resistance of Caco‐2 cell monolayers and brush border associated alkaline phosphatase activity.In conclusion, (1) no deleterious cytochemical consequences (apoptotic, antiproliferative or general cytotoxic effects) were observed on presenting a range of CPP preparations to various human cell systems, indicating that these compounds can be rated harmless at a cellular level, (2) stimulation of IgG‐secretion into culture supernatant of PBL points to possible immunoenhancing properties of CPP preparations.
Transbilayer distribution of aminophospholipids and the oxidative stability of their component polyunsaturated fatty acids
Authors: Kubo Kazuhiro , Sekine Seiji , Saito Morio 
Published: December 2008

AbstractWe examined the relationship between the transbilayer distribution of aminophospholipids, such as phosphatidylethanolamine (PE), PE plasmalogen and phosphatidylserine, and the oxidative stability of polyunsaturated fatty acids (PUFAs) in the aminophospholipids. To modulate the transbilayer distribution of aminophospholipid in liposomes, we used phosphatidylcholine (PC) with two types of acyl chain region: dipalmitoyl (PC16:0) or dioleoyl (PC18:1). In the smaller‐sized liposomes, the proportions of aminophospholipid in the liposomal external layer were significantly higher in liposomes containing PC18:1 than in those containing PC16:0. Additionally, aminophospholipids in the external layer of smaller‐sized liposomes were able to protect their component PUFAs from 2,2'‐azobis(2‐amidinopropane)dihydrochloride‐mediated lipid peroxidation.
Formation of N‐(hexanoyl)ethanolamine, a novel phosphatidylethanolamine adduct, during the oxidation of erythrocyte membrane and low‐density lipoprotein
Authors: Tsuji Kentaro , Kawai Yoshichika , Kato Yoji , Osawa Toshihiko 
Published: December 2008

AbstractThe primary amino groups of biomolecules such as aminophospholipids, as well as proteins, are the potential targets of covalent modifications by lipid peroxidation products; however, little attention has been paid to the modification of aminophospholipids such as phosphatidylethanolamine (PE). The purpose of this study is to characterize the formation of a novel modified phospholipid, N‐(hexanoyl)phosphatidylethanolamine (HEPE), in the reaction of PE with lipid hydroperoxides using mass spectrometric analyses. Upon reaction of egg PE with 13‐hydroperoxyoctadecadienoic acid or other oxidized polyunsaturated fatty acids followed by phospholipase D‐mediated hydrolysis, the formation of N‐(hexanoyl)ethanolamine (HEEA), a head group of HEPE, was confirmed by isotope dilution liquid chromatography/tandem mass spectrometry. Moreover, increasing HEEA was detected in the hydrolysates of oxidized erythrocyte ghosts and low‐density lipoprotein with their increasing lipid peroxidation levels. Collectively, these results suggest that the N‐hexanoylated product of phospholipid, HEPE, can be generated during lipid peroxidation and may serve as one mechanism for the covalent modification of aminophospholipids in vivo.