bluuebunny/crossref_metadata_2025_split huggingface dataset:
Discrimination of a novel type of rat brain δ opioid receptors by enkephalin analog containing structurally constrained cyclopropylphenylalanine (∇Phe)
Authors: Chuman Yoshiro , Yasunaga Teruo , Costa Tommaso , Shimohigashi Yasuyuki 
Published: July 2007

AbstractFour different stereoisomers of cyclopropylphenylalanine (∇Phe) were incorporated into [D‐Ala2,Leu5]enkephalin at the position 4. These conformationally restricted enkephalin analogs were evaluated for their binding characteristics to μ and δ opioid receptors in rat brain. A striking finding is that the E‐(2R,3S)‐isomer binds to a novel class of δ receptors and discriminates this receptor from the ordinary δ receptor. This new type of δ receptor suspected to be a receptor which suppresses the thermal analgesia mediated through μ receptor. The Z‐(2R,3R)‐isomer was very potent with several times more enhanced affinity to δ receptors than to μ receptors, but could not differentiate the δ receptors. The Z‐(2S,3S)‐isomer was weak, and E‐(2S,3R)‐isomer was almost inactive.
Identification of protein kinase C isoforms in marine mussels
Authors: Barcia R. , Lopez‐Garcia J. M. , Girardini J. E. , Ramos‐Martinez J. I. 
Published: July 2007

AbstractIn this paper we have examined the distribution of some isoforms of protein kinase C in different tissues from the sea mussel Mytilus galloprovincialis Lmk. By immunoblot analysis, we have detected the presence of at least three PKC isoforms, all preferably associated with the cellular cytosolic fraction. The Ca2+‐independent form PKC δ was separated from the Ca2+‐dependent forms (PKC α and β) by means of an ionic change chromatography on DE‐52. A comparative study was carried out on the phosphorylatable non‐artificial substrates. The M.B.P. protein proved to be the best substrate, while the worst was HIIIS histone which, however, is frequently used in evaluation assays of the activity.
Rutoxyl [rutin/4‐acetamide‐1‐hydroxy‐2,2,6,6‐tetramethylpiperidinium] is a new member of the class of semi‐natural products of high pharmacological potency
Authors: Metodiewa Diana , Skolimowski Janusz , Kochman Agata , Karolczak Stefan 
Published: July 2007

AbstractA novel complex, Rutoxyl [rutin/4‐acetamide‐1‐hydroxy‐2,2,6,6‐tetramethyl‐piperidinium] was synthesized and its structure and anticancer activity were investigated. The results reported here are consistent with our idea, that the formation of such a complex of two biologically active molecules: polyphenolic flavonoid antioxidant (Rutin) and nitroxylamine of nitroxide antioxidant (Tempace), stabilized by hydrogen bond(s) can result in a supra‐additive properties.
Lys‐49‐phospholipases A2 as active enzyme for β‐arachidonoyl phospholipid bilayer membranes
Authors: Yamaguchi Yoko , Shimohigashi Yasuyuki , Chiwata Tsuyoshi , Tani Ayako , Chijiwa Takahisa , Lomonte Bruno , Ohno Motonori 
Published: July 2007

AbstractPhospholipases A2 containing Lys‐49 have been reported to be extremely weak or inactive as enzyme. We have recently shown that basic proteins I and II (BP‐I and BP‐II), Lys‐49‐PLA2s isolated from the venom of Trimeresurus flavoviridis (Habu snake), are potent to hydrolyze the arachidonate of 2‐arachidonoyl‐1‐stearoyl‐L‐3‐phosphatidylcholine (ASPC) in bilayer vesicles. In order to ensure such enzymatic activity of Lys‐49‐PLA2s, two other Lys‐49‐PLA2s from different snake venoms, myotoxin II (from Bothrops asper) and App‐K49 (form Agkistrodon piscivorus piscivorus), were examined. Myotoxin II was found to be very active, even more potent than BP‐II, liberating about 80% of arachidonic acid from liposomes. App‐K49 was also active (about 50%) for ASPC liposomes. They were very weak or almost inactive for ASPC micelles and monomers. All these Lys‐49‐PLA2s were inactive for ASPC liposomes in the absence of Ca2+. These results clearly demonstrated that Lys‐49‐PLA2s are the enzymes to hydrolyze the C2‐ester bond of ASPC in bilayer membranes.
Micromolar calcium prevents isolated rat liver mitochondria form anoxia‐reoxygenation injury
Authors: Schild Lorenz , Plumeyer Frank , Reinheckel Thomas , Augustin Wolfgang 
Published: July 2007

AbstractRat liver mitochondria were exposed to extramitochondrial free calcium between 0 and 5 μM and/or 5 minutes of anoxia followed by 10 minutes of reoxygenation. At concentrations higher than 4 μM, the membrane potential collapsed indicating the permeability transition of the mitochondrial membrane. Anoxia‐reoxygenation shifted this transition to lower calcium concentrations. Anoxia‐reoxygenation alone resulted in the decrease of ADP stimulated respiration down to about 40 % of its initial value. Between 1 and 2 μM, a protective effect in terms of respiration and oxidative protein modification was found. It is concluced that calcium may suppress the formation of reactive oxygen species during anoxia‐reoxygenation before permeability transition occurs.
Effect of malathion on kinetic parameters of acetylcholinesterase (EC 3.1.1.7)In vitro
Authors: Kamal Mohammad Amjad 
Published: July 2007

AbstractKinetic analysis of the interaction of malathion with camel erythrocyte acetylcholinesterase was investigated in the present study. The Michaelis‐Menten constant (Km) for the hydrolysis of acetylthiocholine iodide (ASCh) was found to be 53.15 μM and the Vmax was 0.287 μmol/min/mg protein. The Kmapp and Vmaxapp were both decreased by increased malathion concentration. Dixon as well as Lineweaver‐Burk plots and their secondary replots indicated that the nature of the inhibition was of the pure uncompetitive type with Ki value estimated as 102.1 ppm. The Kiapp decreased while Vmaxiapp increased by an increased concentration in ASCh.
Mice lacking a functional CHK gene have no apparent defects in the hematopoietic system
Authors: Samokhvalov Igor , Hendrikx Jan , Visser Jan , Belyavsky Alexander , Sotiropolous Damianos , Gu Hua 
Published: July 2007

AbstractNon‐receptor tyrosine kinase Chk has been implicated in hematopoietic development. To study the function of Chk in vivo, we have generated chk‐deficient mice using gene targeting. Overall development of mice homozygous for this mutation was apparently normal. Blood counts, FACS analysis of hematopoietic cell populations, CFU‐C and CAFC assays showed no significant difference between wild type and mutant animals. Thus, the dispensability of Chk for mouse development and hematopoiesis suggests that its function may be redundant in vivo, and most likely be compensated by activity of a closely related protein tyrosine kinase Csk.
Transport of glutathione S‐conjugates in Escherichia coli
Authors: Kałuzna Agnieszka , Bartosz Grzegorz 
Published: July 2007

AbstractThere are no reports concerning glutathione‐S‐conjugates transport in prokaryotic cells, although many studies have been performed in eukaryotic systems. This study demonstrates that glutathione S‐conjugates (2,4‐dinitrophenyl‐S‐glutathione and bimane‐S‐glutathione) are transported also out of Escherichia coli K12 cells. This transport is inhibited by vanadate, fluoride and other inhibitors of glutathione S‐conjugate transport in mammalian cells suggesting a similarity of this process to that known in eukaryotes.
Augmentation of protein kinase C activity and liver cell proliferation in lead nitrate‐treated rats
Authors: Liu Jer‐Yuh , Liu Cheng‐Chung , Wang Chau‐Jong , Yen Cheng‐Chieh , Hsieh Yih‐Shou , Chen Wen‐Kang , Liu Chia‐Pin , Lin Jen‐Kun 
Published: July 2007

AbstractIt is shown that lead alters calcium mediated cellular processes in several biological systems. Calcium enhances the activity of protein kinase C (PKC) which takes part in eliciting cell mitosis. In this study, the effects of lead nitrate on the activity of PKC enzyme were investigated in rat liver. The PKC activity was determined at 12, 24, 48, 72, 120, 168 hours after treatment with a single dose of lead nitrate in male Wistar rats. The results showed that the specific PKC activity of the purified particulate fraction was increased and reached a maximum at 24 hour, and lasted for 48 hours. This augmented activity of PKC was parallel with the increase of the lead level in the purified particulate fraction, although the protein levels of PKC α, PKC δ and PKC ζ were unchanged. Moreover, the frequency of mitotic cells also exhibited a significant increase, and like PKC activity, reached its maximum at 24 hour with accompany signs of liver enlargement. The results suggest that the PKC activation may be involved in promoting liver cell proliferation in lead nitrate‐treated rats.
The role of reactive oxygen species (ROS) in the effector mechanisms of human antimycobacterial immunity
Authors: Fazal Nadeem 
Published: July 2007

AbstractThe aim of this study was to determine the role of reactive oxygen species (ROS) in checking the growth of intracellular mycobacteria within human phagocytes. Peripheral blood‐derived neutrophils and monocyte‐derived macrophages were isolated from Chronic Granulomatous isease (CGD) patients and normal healthy human volunteers. CGD patients are known to have a defect in the NADPH oxidase pathway, resulting in their neutrophils and monocyte‐derived macrophages being unable to generate oxygen radicals which are required to kill intracellular bacteria. The cells were then infected with Bacilte Calmette Guerin (BCG) or Mycobacterium avium, and the bacterial growth in each cell type determined by Colony Forming Units (CFU) estimate. The results obtained indicate that there was no demonstrable inhibition in the intracellular mycobacterial growth within neutrophils or macrophages derived from either Chronic Granulomatous Disease (CGD: deficient in NADPH oxidase pathway) or normal healthy volunteers. Macrophage treatment with either IFN‐γ or TNF‐α had no effect.
Multiple cellular proteins are recognized by the adeno‐associated virus Rep78 major regulatory protein and the amino‐half of Rep78 is required for many of these interactions
Authors: Hermonat Paul L. , Carter Charleata A. , Parham Groesbeck P. , Quirk J. Gerald , Santin Alessandro D. 
Published: July 2007

AbstractAdeno‐associated virus (AAV) encoded Rep78 is a multi‐functional protein which is required for AAV DNA replication, is able to regulate both AAV and heterologous gene expression at the transcriptional level, and appears necessary for site specific integration of AAV DNA into human chromosome 19. By comparison with the analogous replication protein of the polyomaviruses, large T antigen, it seemed likely that Rep78 would interact with cellular proteins to carry out at least some its functions. This study demonstrates that Rep78 is able to interact with multiple cellular proteins from cellular extracts as measured by West(far)‐western, coimmunoprecipitation, and Rep78‐affinity chromatography analysis. Eight cellular proteins of approximately 180, 140, 120, 95, 75, 55, 45, and 35 kDa (+/‐10%), were observed to bind Rep78 in all three assay systems. Two others, of 30 and 24 kDa, were observed in two of three assay systems. Furthermore, using truncated Rep78 proteins, it is demonstrated that the amino‐terminus is required for most Rep78‐cellular protein interactions. However, the extreme carboxy‐terminus of Rep78 was found to be all that is required for binding to the 55 kDa cellular protein.
Differentiation of substrate‐binding sites in pyruvate kinase by selective photoaffinity labeling
Authors: Mozumdar Subho , Wang J. H. 
Published: July 2007

AbstractThe four substrate‐binding sites in porcine liver pyruvate kinase have been labeled with the photoaffinity reagent 8‐azido‐2′‐O‐dansyl‐[α‐32P]ATP (AD‐ATP) under different experimental conditions. In the dark, the native pyruvate kinase was reversibly and competitively inhibited by AD‐ATP, with KI=2.8 μM and KADP=0.18 mM. Under UV‐irradiation, the enzyme was covalently labeled in the presence of Mg2+ by AD‐ATP and inactivated irreversibly. Measurement of this photoinactivation process in the presence of various concentrations of ADP gave KI=4.0 μM and KADP=0.2 mM. A linear plot of the relative specific activity of the partially photolabeled enzyme after gel‐filtration vs. the number of label per pyruvate kinase molecule introduced in the presence of Mg2+ shows that each covalent label completely inactivates a tetrameric pyruvate kinase molecule. In the strict absence of Mg2+, up to three substrate‐binding sites in each pyruvate kinase molecule can be labeled by AD‐ATP without decreasing enzyme activity. Subsequent addition of Mg2+ enables AD‐ATP to label the remaining site and inactivate the enzyme. These observations show that there are one catalytic and three non‐catalytic substrate‐binding sites in each pyruvate kinase molecule. A probable structural reason for possible functional differentiation of intrinsically identical substrate‐binding sites in all tetrameric enzymes is suggested.
Competitive inhibition of mouse brain nitric oxide synthase by amiloride: a case for enzyme cross‐inhibition
Authors: Ascenzi Paolo , Federico Rodolfo , Menegatti Enea , Venturini Giorgio 
Published: July 2007

AbstractAmiloride, a diuretic and antihypertensive drug, inhibits Na+ transporting systems, diamine oxidases and the human urinary plasminogen activator. Present results indicate that amiloride is a competitive inhibitor of mouse brain nitric oxide synthase (NOS; Ki= 4.5×10‐4 M, at pH 7.5 and 37.0°C), but not a nitric oxide (NO) precursor, representing a case for enzyme cross‐inhibition. The decreased levels of NO, as a consequence of NOS inhibition, might induce some clinically‐adverse amiloride reactions, such as an unexpected reduced antihypertensive effect.
Chaperone‐like function of lipocortin 1
Authors: Kim Geum‐Yi , Lee Hee‐Bong , Lee Soo Ok , Rhee Hae Jin , Na Doe Sun 
Published: July 2007

AbstractLipocortin 1 (LC1) is a 37 kDa member of the annexin family of proteins. It has been proposed to act as a mediator of some of the actions of glucocorticoids in anti‐inflammatory and immune suppressive functions. LC1 has been shown to play a role in cell proliferation, apoptosis, and differentiation. However, the exact biological functions of LC1 still remain obscure. Here it is shown that LC1 displays a chaperone‐like function. Stoichiometric amounts of LC1 suppressed thermally induced inactivation and aggregation of the test enzymes citrate synthase and glutamate dehydrogenase. LC1 was also effective in refolding guanine hydrochloride‐denatured glutamate dehydrogenase, as judged by circular dichroism spectroscopy.
Dual temperature model for the estimation of energetics parameters for acetylcholinesterase inhibition by cyclophosphamide
Authors: Kamal Mohammad Amjad 
Published: July 2007

AbstractThe present work addresses the “dual temperature” model for the estimation of Gibb's free energy change (ΔG), enthalpy change (ΔH), heat of activation (ΔH*) entropy change (ΔS), temperature coefficient (Q10) and activation energy (Ea) of chicken brain acetylcholinesterase (AChE) inhibited by cyclophosphaxnide monohydrate (CP). In this investigation, the PZ factor (number of sterically and energy wise favorable collisions occurring between CP and AChE) has also been studied. The inhibitor has considerably increased all energetics parameters except ΔS and Q10. These results are in general agreement with the data from the other reported studies. The significance of the use of CP in cancer therapy and various aspects of thermodynamic parameters have also been discussed.
Isolation of cDNA encoding full‐length rat (Rattus norvegicus) poly(ADP‐ribose) polymerase
Authors: Beneke Sascha , Meyer Ralph , Bürkle Alexander 
Published: July 2007

AbstractPoly(ADP‐ribose) polymerase (EC 2.4.2.30) is a nuclear enzyme which binds to DNA breaks and then catalyzes the covalent modification of acceptor proteins with poly(ADP‐ribose). Poly(ADP‐ribose) polymerase activity contributes to the recovery of proliferating cells from DNA damage and to the maintenance of genomic stability, which may be mediated by effects on chromatin structure, DNA base‐excision repair and cell cycle regulation. We established the complete eDNA sequence of rat poly(ADP‐ribose) polymerase by RT‐PCR and direct sequencing of amplification products and compared it with that of other mammalian species. The amino acid sequence homology is strikingly high. The best conserved regions are the known functional modules ofpoly(ADP‐ribose) polymerase.
Characterisation of bovine structure‐specific recognition protein 1 (SSRP1) cDNA
Authors: Nielsen Peter Kresten , Haaning Jesper , Sottrup‐Jensen Lars 
Published: July 2007

AbstractA partial bovine SSRP1 (structure‐specific recognition protein 1) cDNA has been isolated from a osteoblast cDNA library and sequenced. The bovine SSRP1 cDNA of 1870 bp encoding 460 amino acid residues showed 86% and 98% sequence identity with human SSRP1 at the DNA and protein level, respectively. Expression of SSRP1 mRNA was detected in many human tissues, with a particularly high level in kidney.
Identification of 14 kDa auxin‐binding proteins in a tobacco plasma membrane subfraction responsive to auxin
Authors: Szponarski Wojciech , Peltier Jean‐Benoît , Tena Guillaume , Rossignol Michel 
Published: July 2007

AbstractAuxin binding by tobacco plasma membrane proteins was investigated. After photolabeling with [3H]IAA, 350 polypeptides were resolved on 2D gels and analyzed. Thirteen polypeptides were selected according to physico‐chemical criteria. The labeling of three of them was further shown to increase, after treatment of cells with auxin, specifically in that plasma membrane subfraction where the sensitivity to the hormone of the H+‐ATPase is enhanced by the treatment of cells. These polypeptides were those that exhibited the more specific labeling features according to physico‐chemical criteria. They had similar apparent molecular weight (ca 14 kDa) that distinguished them from other auxin‐binding proteins described up to now, and exhibited similar amino acid compositions. These 14 kDa polypeptides are proposed to constitute a group of new auxin‐binding proteins, potentially involved, within specialized plasma membrane domains, in the stimulation of the proton pump by the hormone.
Multiprotein complex formation on the c‐myc promoter
Authors: Logan Thomas J. , Moberg Kenneth H. , Hall David J. 
Published: July 2007

AbstractThe E2F element is a cis‐acting DNA sequence within the P2 promoter of the c‐myc proto‐oncogene. While it is required for optimal transcription, the multiprotein complexes formed on this site have not been well characterized. We show that in extracts of human glioblastoma cells and NIH3T3 fibroblasts, significant E2F transcription factor binding to the c‐myc E2F site occurs as a both a monomer (the active form) and as only two mutually exclusive complexes with the retinoblastoma gene product (pRb) or the cyclin A protein. The E2F protein monomer was found predominantly in the cytosolic fraction of the cellular extracts while the pRb and cyclin A complexes in the nuclear fraction, indicating that the monomer has novel physical properties. Thus, protein complex formation on the c‐myc E2F site appears to contribute in a unique way to transcriptional activation.
Identification of actin as an estradiol 17‐β‐stimulated protein in the human placenta
Authors: Sudha S. , Kumari Usha , Rao Veena S. , Rao A. Jagannadha 
Published: July 2007

AbstractAddition of estradiol 17‐β to first trimester human placental minces resulted in an increased synthesis of a protein of apparent molecular weight 45 kDa. The specific involvement of estrogen in the stimulation of this protein was established by demonstrating a reduction in the level of this protein by the addition of CGS 16949 A, an inhibitor of aromatase, a key enzyme in the biosynthesis of estradiol 17‐β and ICI 182,780, an estrogen receptor antagonist. The protein was purified to homogeneity and N‐terminal sequencing of two of the internal peptides obtained by enzymatic digestion of the protein, as well as the absence of a free N‐terminal indicated that it could be actin. This was confirmed by Western blotting using commercially available actin antiserum. The role of estradiol 17‐β in the stimulation of actin synthesis in human placenta was also established by monitoring the quantitative inhibition of DNase I by actin.
Differential expression of ferritin heavy chain in THP‐1 cells infected with Mycobacterium bovis BCG
Authors: Lim Jong‐Seok , Lee Seung‐Hwan , Lee Eunsik , Kang Young , Kim Jae Wha , Kim Jin Koo , Kim Hyeon Hoe , Lee Chongwook , Kim Sang Jae , Bai Gill Han , Lee Hee Gu , Kim Kwang Dong , Chung Tai Wha , Choe Yong‐Kyung 
Published: July 2007

AbstractTo identify the host genes induced or suppressed by infection of mycobacteria, the reverse transcriptase polymerase chain reaction (RT‐PCR) and the differential display reverse transcriptase polymerase chain reaction (DD RT‐PCR) methods were used. In this study, cDNAs complement to mRNA extracted from human peripheral monocyte derived naive THP‐1 cells, THP‐1 cells infected with live Mycobacterium bovis BCG, THP‐1 cells treated with heat‐killed BCG, and THP‐1 cells incubated with IgG‐coated glass‐beads were compared on the sequencing gel. One (TG2‐1) of the clones selected by DD RT‐PCR is 446 bp long and is identical to human ferritin heavy (H) chain gene. Northern blot analysis confirmed that ferritin H chain gene has been markedly over‐expressed in monocytic THP‐1 cells incubated with live and dead M. bovis BCG. Differential display techniques of host genes whose expression levels were varied by infection of mycobacteria could provide information about the response of macrophages to mycobacterial infection.
An increase in the carbohydrate moiety of α2‐macroglobulin is associated with systemic lupus erythematosus (SLE)
Authors: Panzironi Claudio , Mo Meng‐yun , Mruk Dolores , Cheng C. Yan , Silvestrini Bruno , Lahita Robert 
Published: July 2007

AbstractUsing lectin blots in conjunction with peptide mapping, α2‐macroglobulin micropurified from systemic lupus erythematosus (SLE) patients was shown to become abnormally glycosylated suggesting the occurrence of complex glycosylation in this pathological condition. To confirm there is indeed a quantitative increase in specific monosaccharides in this protein; α2‐macroglobulin was micropurified from a battery of 37 serum samples which included 6 normal donors (3 male and 3 female), 23 SLE patients, 6 rheumatoid arthritis patients, 1 mixed connective tissue disease patient, and 1 Sjogren's syndrome patient; for carbohydrate analysis. It was noted that the concentration of total monosaccharides in α2‐macroglobulin micropurified from serum samples of SLE patients is significantly higher than normal donors with a mean±SD of 188±410 μg/mg protein (SLE, n=23) versus 14.5±4 μg/mg protein (normal, n=6) even though there was a high variation in the level of monosaccharides among the SLE patients. An increase in oligosaccharides in α2‐macroglobulin from SLE patients compared to normal subjects was confirmed by concanavalin A (Con A) blots using peptide fragments derived from the micropurified protein. Since the interaction of peptide fragments derived from α2‐macroglobulin with Con A requires the presence of mannose and/or glucose residues, we have also examined if there are any correlations between the levels of mannose and glucose in α2‐macroglobulin and SLE. The concentration of mannose (38±60 μg/mg protein) in α2‐macroglobulin derived from SLE patients was significantly higher than normal donors (mannose, 4.8±1 μg/mg protein) however, the concentration of glucose in α2‐macroglobulin derived from SLE patients when compared to normal donors was not statistically significant, 18±20 μg/mg protein in SLE versus 2±0.5 μg/mg protein in normal donors due to high variation between samples. Also, the concentration of galactose in α2‐macroglobulin from SLE patients was significantly higher than normal donors (45.7±173 μg/mg protein versus 0.13±0.03 μg/mg protein). These results illustrate quantification of carbohydrate in selected glycoproteins such as α2‐macroglobulin may be a novel and alternative clinical marker for SLE.