bluuebunny/crossref_metadata_2025 huggingface dataset:
Cell-membrane phospholipase C is involved in inducing the antiviral effect of interferon
Authors: Popescu L. M. , Cernescu C. , Moraru I. I. , Constantinescu St. N. , Baltã F. , Manciulea M. , Brãiloiu E. , Buzilã L.
Published: February 2005

A monospecific inhibitory antibody directed to phospholipase C (phosphoinositidase C) blocked the antiviral effect of human interferons alpha and beta when tested on human quiescent fibroblasts challenged with the vesicular stomatitis virus. This action was due to specific inhibition of polyphosphoinositide hydrolysis because (a) the F(ab′)2 fragment of the antibody molecule was also inhibitory; (b) excess antibodies directed to phospholipase A2 and to a phosphatidylcholine-preferring phospholipase C did not have any inhibitory effect, and (c) the combination of 12-O-tetradecanoylphorbol-acetate and calcium ionophore A23187 had an interferon-like antiviral effect which was not influenced by the inhibitory anti-phospholipase C antibodies. To avoid an interferon-like effect due to induction of interferon by second messengers, Vero cells, which lack interferon biosynthesis, were also used. Liposomes containing inositol 1,4,5-triphosphate and 1-oleoyl-2-acetyl-rac-glycerol protected Vero cells against the infection with the vesicular stomatitis virus. These results taken together show that phosphoinositide-derived second messengers are involved in triggering the antiviral effect of interferons alpha and beta.
The influence of interferon alpha and gamma, singly or in combination on human natural cell mediated cytotoxicity
Authors: Rawlinson Lesley , Dalton Barbara J. , Rogers Kenneth , Rees Robert C.
Published: February 2005

The influence of interferon alpha and gamma alone or in combination on the augmentation of human natural cytotoxicity was studied. Treatment of peripheral blood lymphocytes with IFN-α led to a rapid augmentation of NK activity, in contrast to IFN-γ where target cell killing was observed only following 18 hrs exposure of lymphocytes to IFN-γ. The results of the single cell assay paralleled those obtained using the Chromium release test, but neither interferon type caused an increase in the number of target binding lymphocytes. The combined effect of IFN-α and IFN-γ in stimulating human natural cytotoxicity demonstrated individual lymphocyte responses to be variable. Exposure of lymphocytes to IFN-α and IFN-γ for 18 hrs prior to assay for cytotoxicity usually decreased the level of cytotoxicity compared with control values, whereas other treatment regimes gave an additive and sometimes synergistic effect. Only treatment with IFN-α for 18 hrs and IFN-γ for one hr produced a synergistic response in the majority of individuals tested. We conclude from this study that individual responses to IFN-α and IFN-γ alone or in combination are variable and dependent upon timing of exposure of lymphocytes to individual interferon types, and possibly reflects the donor status at the time of sampling.
Effects of polymyxin B on the sarcoplasmic reticulum membrane
Authors: Ktenas T. B. , Sotiroudis T. G. , Evangelopoulos A. E.
Published: February 2005

Polymyxin B, a cyclic peptide antibiotic, inhibits Ca2+-ATPase, p-nitrophenyl phosphatase and phosphorylase kinase activities associated with rabbit skeletal muscle sarcoplasmic reticulum membranes; 50% inhibition is induced by 100 μM, 130μM and 550 μM of polymyxin respectively. The fluorescence intensity of fluorescein isothiocyanate-labeled Ca2+-ATPase, decreases in the presence of polymyxin (50% of the total decrease at 70 μM polymyxin). On the other hand, the polypeptide inhibits calmodulin-dependent endogenous phosphorylation of 60 kDa, 20 kDa and 14 kDa membrane proteins, while an increase of calmodulin-dependent phosphorylation is observed in 132 kDa and 86 kDa proteins.
Changes of subcellular localization of Thy-1 antigen during thymic myoid cell differentiation
Authors: Kikuchi Aiko , Kamo Isao , Fujisawa Kazumi , Nonaka Ikuya
Published: February 2005

Using a quantitative enzyme immunoassay, Thy-1 antigen expressed by a rat myoid cell line R615B2 was detected mainly on the cell surface at a single cell stage, whereas at the stage of forming myotubes, Thy-1 was found predominantly in the cytoplasm. The muscle specific creatine kinase activity also increased in association with the shift of Thy-1 from the cell surface to the cytoplasm, suggesting biological significance of Thy-1 redistribution in muscle differentiation from single cells to multinucleated cells.
Effects of dexamethasone on carnitine metabolism in liver and extrahepatic tissues
Authors: French Timothy J. , Good Anthony W. , Palmer T. Norman , Sugden Mary C.
Published: February 2005

The in vivo effects of dexamethasone administration on liver and extrahepatic tissue carnitine concentrations were assessed in 48-h-starved rats. In heart and kidney, but not in liver, dexamethasone significantly increased total carnitine concentration. Acute (2.5 h) treatment with 2-tetradecylglycidate (TDG), a specific inhibitor of carnitine palmitoyl transferase 1, not only increased total hepatic carnitine concentrations, but also permitted an effect of dexamethasone (a further increase in hepatic carnitine concentration). The results are discussed in terms of acute (substrate-mediated) and chronic (hormonal) control of carnitine turnover.
Rat liver carbonic anhydrase I is not sexually dimorphic but is estrogen repressible
Authors: Jeffery S. , Carter N. D. , Wilson C. A.
Published: February 2005

Carbonic anhydrase (CA) isozymes CAII and CAIII are known to exhibit sexual dimorphism in rat liver, and the levels of these isozymes are affected by sex hormones. In this paper we show that the isozyme CAI is present at low levels in rat liver, with no difference in concentration between male and female rats. Estrogen and diethylstilbestrol reduce CAI levels in both sexes.
Putative repressor binding sites in the regions mediating transcriptional control of viral and cellular genes
Authors: Renan Michael J.
Published: February 2005

In this study, the sequences of several cellular genes (c-myc, c-fos, c-sis, c-mos, and the genes for urokinase, heat shock proteins, interleukin-2 and its receptor), thought to be controlled by negative regulatory factors, were examined. As a result of this comparison, multiple (and often clustered) copies of a 12 basepair (bp) element were identified in the flanking regions of these genes. Moreover, sequences with close homology to this 12 bp element were identified in specific control regions of some DNA and RNA tumor viruses. A consensus sequence (TTG nnn TTTTTT) was derived from an analysis of 111 of these elements. These sequence homologies have yielded a coherent first hypothesis, namely that this 12 bp element is the binding site of a transcriptional repressor protein.
Mofification of body composition by clenbuterol in normal and dystrophic (mdx) mice
Authors: Rothwell Nancy J. , Stock Michael J.
Published: February 2005

Female dystrophic mice (mdx on C57 Black background) gained weight more rapidly than age-matched controls and had a higher body fat content (% body weight), a slightly lower protein content and a reduced mass of muscle. Chronic treatment (21 d) of the mice with the β2-agonist clenbuterol stimulated weight gain in both genotypes without affecting energy intake. Clenbuterol increased the mass of the gastrocnemius and soleus muscle by 13% and 29% in normal and dystrophic mice, respectively, and raised body protein but depressed body fat. Body water and energy content were unaffected by clenbuterol, but the ratio of protein to fat in the carcasses was enhanced by 17% in normal and 56% in dystrophic mice following clenbuterol treatment. Thus, the β2-agonist restored the body composition of dystrophic mice to normal and enhanced the protein to fat ratio in both these and normal mice.
Inhibition of chlorophyll synthesis in Hordeum vulgare by 3-amino 2,3-dihydrobenzoic acid (gabaculin)
Authors: Hill Corinne M. , Pearson Sharon A. , Smith Arnold J. , Rogers Lyndon J.
Published: February 2005

Gabaculin (3-amino 2,3-dihydrobenzoic acid) is shown to be a very potent inhibitor of chlorophyll formation in Hordeum vulgate. Exposure of leaf segments to 30/μM gabaculin results in an 80% inhibition of chlorophyll synthesis, and this is paralleled by a decrease in carotenoid. Dual-inhibitor studies with dioxoheptanoic acid, which is an inhibitor of δ-aminolaevulinic acid dehydratase, show that gabaculin inhibits an earlier step than dioxoheptanoic acid and affects δ-aminolaevulinic acid synthesis rather than its subsequent metabolism.
Cyclic AMP response to vasoactive intestinal peptide and β-adrenergic or cholinergic agonists in isolated epithelial cells of rat ventral prostate
Authors: Carmena María-José , Prieto Juan-Carlos
Published: February 2005

Vasoactive intestinal peptide (VIP) and the β-adrenergic agonist isoproterenol stimulated cyclic AMP formation through independent receptors in isolated epithelial ceils of rat ventral prostate. The specific β-adrenergic antagonist propranolol inhibited the stimulatory effect of isoproterenol but not that of VIP. Besides small differences in the efficiency of both agents, results indicated that isoproterenol was 500 times less potent than VIP. Acetylcholine did not modify the basal cyclic AMP levels but inhibited the accumulation of the cyclic nucleotide in the presence of either VIP or isoproterenol. The inhibitory action of muscarinic receptors was calcium-dependent. The coexistence of receptors for cholinergic, adrenergic and peptidergic agents which can regulate cyclic AMP suggests that the functions of prostatic epithelium may be interdependently controlled by multiple neural effectors.
Structural characteristics of a major seed albumin of Pisum sativum
Authors: Zimniak-Przybylska Zdzislawa , Hempel John , Przybylska Janina , Jörnvall Hans
Published: February 2005

The major pea seed albumin from Pisum sativurn was carboxymethylated, cleaved with CNBr, and submitted to sequence analysis of the fragments in order to characterize the structural organization of the protein chains. Four major pools of largely homogeneous CNBr fragments were obtainede and likely N-and C-terminal fragments were identified. StruCtural analysis suggested the presence of single positions with microheterogeneities. It also revealed structures with long segments of distinct homology (52% structural identity), indicating the presence of different but related protein chains, or less likely, of repetitive structural elements within a chain. However, preparations appear largely homogeneous in protein class, and contain similar polypeptide chains of about 200 residues in mainly hydrophilic structures, with few methionine and cysteine/half-cystine residues.
C1r serine proteinase of human complement: A case of intramolecular autolytic activation
Authors: Arlaud Gérard J. , Colomb Maurice G. , Villiers Christian L.
Published: February 2005

This paper presents a short review of our contribution to the knowledge of the structure and function of human Clr, the activation unit of C1, the first component of the classical pathway of complement. On the basis of the domain structure of Clr, a model accounting for its autolytic activation mechanism is proposed. We suggest that this represents the basic mechanism of C1 function.
Genes for the protein antigens of the tuberculosis and leprosy bacilli
Authors: Bloom Barry R. , Mehra Vijay , Young Richard A.
Published: February 2005

The λgt11 expression vector permitted us to survey protein antigens of Mycobacterium leprae and Mycobacterium tuberculosis expressed in Escherichia coll. Using monocional antibodies, recombinant clones were detected producing three major antigens of M. tuberculosis and five major protein antigens of M. leprae. These recombinant antigens produced in E. coli should prove useful for diagnosis, epidemiology and possibly the development of recombinant mycobacterial vaccines.
Studies on Nα-acylated proteins: The N-terminal sequences of two muscle enolases
Authors: Chin Christopher C. Q. , Wold Finn
Published: February 2005

A standard procedure for the identification of the N-terminal amino acid in Nα-acylated proteins has been developed. After exhaustive proteolysis, the amino acids with blocked α-amino groups are separated from positively charged, free amino acids by ion exchange chromatography and subjected to digestion with acylase I. Amino acid analysis before and after the acylase treatment identifies the blocked N-terminal amino acid. A survey of acylamino acid substrates showed that acytase will liberate all the common amino acids except Asp, Cys or Pro from their N-acetyl- and N-butyryl derivatives, and will also catalyze the hydrolysis of N-formyl-Met and N-myristyl-Val. Thus, the procedure cannot identify acylated Asp, Cys or Pro, nor, because of the ion exchange step, Nα-acyl-derivatives of Arg, Lys or His. Whenever the protease treatment releases free acylamino acids, the remaining amino acids should be detected. When applied to several proteins, the procedure confirmed known N-terminal acylamino acids and identified acyl-Ser in enolases from chum and coho salmon muscle and in pyruvate kinase from rabbit muscle, and acyl-Thr in phosphofructokinase from rabbit muscle. The protease-acylase assay has been used to identify blocked peptides from CNBr- or protease-treated proteins. When such peptides were treated with 1n HCl at 110° for 10 min, sufficient yields of deacylated, mostly intact, peptide were obtained to permit direct automatic sequencing. The N-terminal sequences of rabbit muscle and coho salmon enolase were determined in this way and are compared to each other and to the sequence of yeast enolase.
Activation of protein kinase C modulates the expression of the T3/T cell antigen receptor complex on human T lymphocytes
Authors: Davies Adelina A. , Cantrell Doreen A. , Crumpton Michael J.
Published: February 2005

Activators of protein kinase C induced a rapid decrease (within 15 min) in the surface expression of the T3 antigen and T-lymphocyte antigen receptor (Ti) on HPB-ALL cells, and a concomitant phosphorylation of the T3 γ and δ polypeptides; the γ chain was more extensively phosphorylated than the δ chain. No phosphorylation of the T3 ∊ chain and the Ti α and β polypeptides was detected. Evidence was obtained that the T3 γ chain is phosphorylated only on serine residues.
More homologies among the vertebrate plasma proteins
Authors: Doolittle R. F.
Published: February 2005

Many of the proteins of vertebrate blood plasma share common ancestry. As more sequences are reported, the network of relationships continues to expand in unexpected directions. Computer analysis now reveals that a minor plasma protein of unknown function, gamma-trace protein, is related to the kininogen family. Some other possible relationships have been uncovered also, including a resemblance between the histidine-rich hinge regions of high molecular weight kininogen and hemopexin and between Factor VIII and Von Willebrand Factor.
Changes in topoisomerase I activity after irradiation of lymphoid cells
Authors: Johnstone Alan , McNerney Ruth
Published: February 2005

The activity of topoisomerase I in nuclear extracts increased about three-fold 5 min after γ-irradiation (840–2500 rads) of human peripheral blood lymphocytes or cultured lymphoblastoid cells. The change may reflect modification of the enzyme by nuclear ADP-ribosyl transferase, which is known to be activated by DNA breaks.
Characterization of a human granulocyte differentiation antigen (CDw15) commonly recognized by monoclonal antibodies
Authors: McCarthy Noirin C. , Albrechtsen Merete T. , Kerr M. A.
Published: February 2005

Many different anti-human granulocyte monoclonal antibodies recognize the same carbohydrate antigen which contains the trisaccharide 3-fucosyl-N-acetyllactosamine. The antigen is expressed mainly on two cell surface glycoproteins of molecular weights around 105 K and 160K which are apparently not members of the LFA-1 family of proteins. Although specific for granulocytes in blood, the antigen is expressed on a wide range of non-haemopoietic cell types.
Conformation and processing of cathepsin D
Authors: Pain Roger H. , Lan Tamara , Turk Vito
Published: February 2005

Cathepsin D occurs in two forms, a single polypeptide chain (Mr 44000) and a non-covalent complex of two peptides of Mr 14000 and 30000 that is derived by proteolytic processing of the 44000 polypeptide. The two forms from bovine spleen are closely similar in secondary structure content, in aromatic amino acid environment and in the two step denaturation behaviour. Enzyme activity is lost irreversibly on denaturation but conformation can be partially regained. The two separated chains will only refold partially and this is related to their positions in the overall structure of cathepsin D. It is suggested that the processing step is related to protein turnover.
Preparation and properties of FabIgG, a chimeric univalent antibody designed to attack tumour cells
Authors: Stevenson G. T. , Glennie M. J. , Paul F. E. , Stevenson F. K. , Watts H. F. , Wyeth P.
Published: February 2005

In order to promote the killing of tumour cells by antibody a derivative has been synthesized in which Fab'γ from xenogeneic antibody is thioether-bonded to half-cystine on normal IgG of the species to be treated. The resulting entity, FabIgG, is obtained with about a 40% yield of the starting Fab'γ. Being univalent it evades antigenic modulation. It activates complement efficiently, is minimally immunogenic, and appears to be catabolized at the slow rate characteristic of autologous IgG.
Antigen-induced suppression: The role of Class I major histocompatibility antigens
Authors: Wood Kathryn J. , Morris Peter J.
Published: February 2005

The role of Class I major histocompatibility (MHC) antigens in the induction of specific suppression of graft rejection has been investigated. Two experimental transplantation models have been used ’ fully vascularized heterotopic Cardiac altografts in the mouse and fully vascularized orthotopic renal allografts in the rat. Preparations of ceils expressing Class I MHC antigens, for example highly purified preparations of rat erythrocytes or platelets or mouse L cells (H2k) transfected with the D locus Class I gene of the b haplotype, LDb-1 cells, were used to pretreat recipients prior to transplantation, The function of the allograft was monitored in order to assess any beneficial effects induced by Class I MHC antigens. The results obtained implicate Class I MHC as important in the induction of specific immunosuppression of vascularized allograft rejection.
Adaptive changes in the concentration of the mitochondrial ‘uncoupling’ protein in brown adipose tissue of hamsters acclimated at different temperatures
Authors: Trayhurn Paul , Richard Denis , Jennings Graham , Ashwell Margaret
Published: February 2005

The effect of acclimation at different temperatures on the activity of interscapular brown adipose tissue has been investigated in the hamster, a hibernator. Between 31° and 4°C the cytochrome oxidase activity of the tissue increased 4- to 5-fold, mitochondrial GDP binding per mg of mitochondrial protein doubled, and the amount of uncoupling protein rose from 1.7% to 5.4% of total mitochondrial protein. It is concluded that there are clear adaptive changes induced by temperature in brown adipose tissue of the hamster, but the changes are limited in comparison with those in the mouse.
Thyrotropin-releasing hormone stimulates inositol phosphate production in normal anterior pituitary cells and GH3 tumour cells in the presence of lithium
Authors: Baird John G. , Dobson Pauline R. M. , Wojcikiewicz Richard J. H. , Brown Barry L.
Published: February 2005

Phosphatidylinositol (Ptd Ins) breakdown in response to thyrotropin-releasing hormone (TRH) was measured after preincubation of both normal rat anterior pituitary cells and GH3 turnout cells with [3H]inositol by the determination of [3H]inositol phosphate accumulation in the presence of lithium (which inhibits myo-inositol phosphatase). The method employed, which was originally developed for use with tissue slices, was adapted for isolated cells in monolayer culture. In GH3 cells, TRH stimulated the breakdown of phosphoinositide in a manner similar to that reported previously using alternative methods. Furthermore, in normal male anterior pituitary cells the dose-response profile for TRH stimulation of inositol phosphate accumulation was found to correlate well with the dose-response profile for TRH stimulation of prolactin secretion. As this response was maintained in the absence of added calcium, the breakdown of phosphoinositide would appear to be implicated as an event preceding calcium mobilization.
Mapping of the c-sis oncogene on human chromosome 22 with respect to the breakpoint associated with chronic myeloid leukaemia
Authors: Goyns Malcolm H.
Published: February 2005

Chronic myeloid leukaemia (CML) cells are often characterized by the presence of a small chromosome 22, in which most of the q arm has been translocated to chromosome 9. Using cell hybrids containing different parts of chromosome 22 I have mapped the c-sis oncogene, which is known to be situated on chromosome 22, to a region distal to the CML breakpoint (22q112) and proximal to 22q13. This demonstrates that c-sis is translocated to chromosome 9 in CML cells.
Interaction of antimalarial drugs with hemin
Authors: Panijpan B. , Mohan Rao Ch. , Balasubramanian D.
Published: February 2005

Hemin (ferriprotoporphyrin IX) is shown to form complexes with the chloroquine class of antimalarial drugs. The Soret band of hemin becomes optically active upon the addition of chiral drugs. Results on the hemin-induced quenching of the fluorescence of chloroquine are consistent with the formation of a 2:1 hemin:drug complex with a formation constant of 1.4 × 107 at 298 K. Also a direct comparison of the drug-treated and drug-free parasites themselves, by the noninvasive photoacoustic spectroscopic method, reveals an in vivo interaction between endogenous hemin and the added drug.
Do centrioles contain ribosomes?
Authors: Kallenbach Rein J.
Published: February 2005

Centrioles induced via a number of parthenogenetic agents regularly reveal the presence of one or more granules within their central cores. Though not a new discovery, these centriolar granules have carefully been re-evaluated here. Considering various criteria, it is proposed that these granules are intra-centriolar ribosomes. More specifically, they are more comparable to 705 ribosomes than to 805 cytoribosomes. The data suggest that within the lumen of centrioles, certain centriolar proteins are synthesized on ribosomes that may be uniquely centriolar.
New concepts on the structure of the neuronal networks: The miniaturization and hierarchical organization of the central nervous system
Authors: Agnati Luigi F. , Fuxe Kjell
Published: February 2005

The hypothesis is introduced that miniaturization of neuronal circuits in the central nervous system and the hierarchical organization of the various levels, where information handling can take place, may be the key to understand the enormous capability of the human brain to store engrams as well as its astonishing capacity to reconstruct and organize engrams and thus to perform highly sophisticated integrations. The concept is also proposed that in order to understand the relationship between the structural and functional plasticity of the central nervous system it is necessary to postulate the existence of memory storage at the network level, at the local circuit level, at the synaptic level, at the membrane level, and finally at the molecular level. Thus, memory organization is similar to the hierarchical organization of the various levels, where information handling takes place in the nervous system. In addition, each higher level plays a role in the reconstruction and organization of the engrams stored at lower levels. Thus, the trace of the functionally stored memory (i.e. its reconstruction and organization at various levels of storage) will depend not only on the chemicophysical changes in the membranes of the local circuits but also on the organization of the local circuits themselves and their associated neuronal networks.
Membrane fluidity and myotonia: Effects of cholesterol and desmosterol on erythrocyte membrane fluidity in rats with 20,25-diazacholesterol-induced myotonia and on phospholipid liposomes
Authors: Ashraf J. , Feix J. B. , Butterfield D. A.
Published: February 2005

Previous spin-label and electromyographic experiments with rats fed 20,25-diazacholesterol, an inhibitor of the biosynthetic conversion of desmostero to cholesterol, demonstrated an increased erythrocyte membrane fluidity and myotonia, a prolonged muscle contraction upon stimulation. The current studies with rats showed normal erythrocyte fluidity in animals fed 20,25-diazacholesterol but maintained on a high-cholesterol diet and no myotonia. Studies of model membrane systems composed of phospholipid vesicles containing desmosterol, cholesterol, or both demonstrated that desmosterol increased membrane lipid fluidity relative to cholesterol, suggesting that in 20,25-diazacholesterol-induced myotonia, in which desmosterot accounts for 85% of the plasma sterol, the increased membrane fluidity previously observed in erythrocytes and sarcolemma in this animal model of human congenital myotonia may be due to desmosterol.
Production of a monospecific antiserum to cathepsin L: The histochemical location of enzyme in rabbit fibroblasts
Authors: Etherington David J. , Mason Robert W. , Taylor Mark A. J. , Wardale R. John
Published: February 2005

A polyclonal antibody against rabbit cathepsin L was raised in goats and shown to be specific for both active and inactive enzyme. Using this antibody we have examined the distribution of cathepsin L in primary rabbit skin fibroblasts by immunohistochemistry and found that all the enzyme is located within lysosomal granules. At confluence many cathepsin-L-containing lysosomes were seen in each celt. A new but nonspecific histochemical substrate for cathepsin L was tested and a similar distribution was obtained. Our results indicate that the immunohistochemical technique can be reliably employed for the specific location of cathepsin L in cells and tissues.
Size heterogeneity of prolactin secreted from and stored in the rat anterior pituitary gland in vitro
Authors: Bentley Andrew M. , Surowy Teresa K. , Wallis Michael
Published: February 2005

The size heterogeneity of rat pituitary prolactin was investigated using anterior pituitary glands from female rats incubated in vitro and gel filtration on Sephadex G-100. Monomeric prolactin was preferentially secreted compared with dimeric and ‘trimeric” material. When glands were incubated with dopamine, prolactin secretion was inhibited and the relative proportion of dimer in the gland (but not the medium) was decreased. Morphine sulphate reversed the effect of dopamine on prolactin secretion and on the proportion of prolactin in the gland that was in the dimeric form. The results suggest that monomeric prolactin is more readily secreted than dimer, and that dopamine decreases the production or stability of the dimer.
Monoclonal antibodies against plasma protease inhibitors: II. Production and characterization of 25 monoclonal antibodies against human α1-antitrypsin. Correlation between antigenic structure and functional sites
Authors: Hérion P. , Siberdt D. , Francotte M. , Urbain J. , Bollen A.
Published: February 2005

Twenty-five hybridomas secreting monoclonal antibodies against human α1-antitrypsim have been produced by the cell-fusion techmque (Kóhler and Milstein, 1976). All antibodies are specific for α1-antitrypsim and carry γ1-antitrypsim heavy chains and κ light chains. Inhibition experiments showed that these monoclonal antibodies define three independent antigenic regions on the α1-antitrypsim molecule; one of these domains appears to be involved in the interaction between α1-antitrypsim and trypsin. In addition, one monoclonal antibody, AATY39, was used to develop an enzyme-linked immunosorbent assay capable of detecting low levels of α1-antitrypsim in the range of 1 to 2 ng/ml.
A micro-method for the detection of butyrylcholinesterase secreted by hepatocytes in vitro
Authors: Schuman Richard F. , Brimfield A. A. , Hunter Kenneth W.
Published: February 2005

A new assay has been developed for detection of butyrylcholinesterase (EC 3.1.1.8) activity based upon the change in absorbance of phenol red, caused by the release of butyric acid from the substrate. Using commercially available enzyme prepared from horse serum, linear, dose-related decreases in absorbance were obtained, generally with correlation values of 0.965 or greater. The assay was modified and used to detect enzyme activity in the supernatants from primary cultures of mouse hepatocytes. The enzyme-mediated response was inhibited by NN′-diisopropylphosphorodiamidic anhydride, a specific inhibitor of butyrylcholinesterase.
Transcription of chemically acetylated chromatin with homologous RNA polymerase B
Authors: Csordas A. , Multhaup I. , Grunicke H.
Published: February 2005

Homologous RNA polymerase B was used to examine the template properties of rat liver chromatin modified by acetic anhydride. Transcription of chromatin was strongly stimulated on the chemically acetyiated template. Under conditions of reinitiation inhibition there was an approximately two-fold increase in the number of initiation sites on the acetylated chromatin. A new method of chemical acetylation of histones, with a high degree of specificity, is presented.
Vasopressin promotes the metabolism of near-physiological concentration of glutamine in isolated rat liver cells
Authors: Martin Guy , Baverel Gabriel
Published: February 2005

In isolated rat liver cells, vasopressin, like glucagon, promotes the metabolism of glutamine used at nearphysiological concentration (1 mM). These findings indicate that, in vivo, both hormones might participate in the control of hepatic gluconeogenesis and ureogenesis from glutamine.
Multienzyme complexes of eukaryotic aminoacyl-tRNA synthetases
Authors: Dang Chuan V. , Dang Chi V.
Published: February 2005

The high-molecular-mass aminoacyl-tRNA synthetase complexes in higher eukaryotes are discrete non-artifactual multienzyme complexes of similar composition which can be purified from different tissues of different species by different techniques. These high-Mr complexes are composed of synthetases in simple stoichiometric ratios. The synthetases most often found in high-Mr complex are those specific for Arg, Gln, Glu, Ile, Leu, Lys, and Met. Several synthetases are shown to contain carbohydrates suggesting a major difference between the eukaryotic and prokaryotic enzymes and the possibility that carbohydrates may be involved in complex formation. The functional significance of the high-Mr complexes is unclear but reduction of thermolability of the synthetases by complex formation appears well established. The activation and inactivation of synthetase activities in high-Mr complex by dephosphorylation and phosphorylation and the ability of the synthetases to synthesize Ap4A suggest that synthetases in complexes may be intricately involved in control of DNA replication, transcription, and translation. Localization of Met-tRNA synthetase to the endoplasmic reticulum by immunfluorescence microscopy suggests that part of the protein synthesis machinery is highly organized on intracellular membranes and that this may provide for compartmentation of intracellular amino acid and aminoacyl-tRNA pools.
Monoclonal antibodies against human placental sphingomyelinase
Authors: Freeman Stuart J. , Davidson D. Joan , Shankaran Prema , Callahan John W.
Published: February 2005

Monoclonal antibodies against human placental acid sphingomyelinase have been raised. The antibodies are all of the IgG1 type, and are quite specific for the enzyme. One of the antibodies has been used to demonstrate a common antigenic identity of three polypeptides (mol. wts. 90 000, 72 000, and 48 000) of a purified sphingomyelinase preparation.
Infectious scrapie agent is apprently not as small as recent claims suggest
Authors: Diringer H. , Kimberlin R. H.
Published: February 2005

A potentially important claim that the minimum size of infectious scrapie agent is 50 000 Mr or less has been investigated. Our results suggest that the agent is larger and that the original experiment was mis-interpreted.
Protein synthesis in liver, skeletal muscle, and brown adipose tissue of rats fed a protein-deficient diet
Authors: Emery P. W. , Rothwell N. J. , Stock M. J.
Published: February 2005

Feeding protein-deficient diets to rats is known to stimulate diet-induced thermogenesis and activate brown adipose tissue (BAT). The fact that BAT protein content, unlike that of other tissues, is unnaffected by protein deficiency prompted us to measure tissue protein synthesis in vivo in animals maintained on normal- (18.8%) and low- (7.6%) protein (LP) diets. Protein synthesis was depressed in the liver of the LP rats due to a fall in RNA activity, with no change in RNA content, and synthesis was also reduced in skeletal muscle from the LP group, but this was due to decreased RNA content with no change in RNA activity. Conversely, protein synthesis, RNA, DNA, and protein content of interscapular BAT were all unaltered in protein-restricted animals. These data indicate that, unlike liver, skeletal muscle, and whole carcass, BAT protein synthesis is not reduced in protein-restricted rats, and this may be related to activation of thermo-genesis in the tissue.
A multiplicity of erythrocyte glycolipids of the neolacto series revealed by immuno-thin-layer chromatography with monoclonal anti-I and anti-i antibodies
Authors: Uemura K. , Childs R. A. , Hanfland P. , Feizi Ten
Published: February 2005

The thin-layer-chromatography immunostaining procedure was applied to human erythrocyte glycolipids using monoclonal anti-i and anti-I antibodies which are directed against epitopes on linear and branched carbohydrate chains of the neolacto (poly-N-acetyl-lactosamine) series. An examination of native and mild-acid-treated glycolipids from normal adult (Iadult antigen type), neonatal (icord), and I-antigen-deficient adult (iadult) erythrocytes enabled certain structural inferences to be made as follows: (a) cells of both I and i phenotypes contain a multiplicity of glycolipids of the neolacto series whose backbones consist of 8 or more sugar residues; (b) the octasaccharide backbones are predominantly linear in cells of i phenotype and branched in those of I type; and (c) more complex glycolipids having decasaccharide and larger backbones with both linear and branched sequences occur in erythrocytes of both phenotypes, 0
The β2 subunit of human placenta hexosaminidase (Hex) A and B is a non-random association of the two polypeptides αa and βb
Authors: O'Dowd B. , Mahuran D. , Lowden J. A.
Published: February 2005

The subunit structures of placental Hex A and B have previously been assigned as βa and βb, respectively. The β2 subunit is composed of two non-identical polypeptide chains, βa and βb. Purified Hex A and B were fractionated on a chromatofocusing column, and the fractions were reduced and then alkylated with iodo-I-14C-acetamide. The polypeptide chains were separated by polyacrylamide-gel isoelectric focusing. From the radioactivity measurements of the polypeptides a constant value for β2 was obtained in all the chromatofocusing fractions, demonstrating a non-random structure of (β2) in each β2 subunit.
Trout red blood cells treated with proteases fuse when placed on glass slides
Authors: Bols N. C. , Yip J. H. K. , Wolff B. R.
Published: February 2005

Treatment of trout red blood cells (RBC) with proteases and polyethylene glycol (PEG) either successively or concurrently caused cell fusion. Neither PEG nor protease treatment alone brought about the fusion of cells in suspension. However, incubation of RBC on glass slides with proteases caused extensive fusion.
Ribonucleolytic activity of bovine spermatozoal plasma and acrosomal membranes
Authors: Shivaji Sisinthy , Bhargava Pushpa M.
Published: February 2005

We show here the presence of an integral, strong RNAase-A-like ribonucleolytic activity in the plasma and outer acrosomal membranes of bovine spermatozoa. A part of this activity is extractable by salt or detergent.
Chronic effects of β2 agonists on body composition and protein synthesis in the rat
Authors: Emery P. W. , Rothwell N. J. , Stock M. J. , Winter P. D.
Published: February 2005

Chronic treatment of rats with the β2-adrenergic agonists clenbuterol and fenoterol over 16–19 d raised energy intake, expenditure, and body weight gain but did not affect fat or energy deposition, and body protein gain was increased by 50 and 18%, respectively. Both drugs increased the protein content and mitochondrial GDP-binding capacity of brown adipose tissue. Clenbuterol did not affect plasma insulin, growth hormone, or triiodothyronine levels, although insulin levels were reduced by fenoterol. Both drugs caused hypertrophy of skeletal muscle (gastrocnemius), and muscle protein synthesis in vivo (fractional rate) was elevated by 34 and 26% in clenbuterol and fenoteroltreated rats, respectively.
Ca2+-sensitive permeability changes caused by influenza virus
Authors: Patel Kalpana , Pasternak Charles A.
Published: February 2005

Influenza virus added to Lettré cells at pH 5.3 induces a permeability change similar to that elicited by Sendal virus at pH 7.4: K+ and Na+ equilibrate across the plasma membrane and low-molecular-weight phosphorylated compounds leak out of cells, which remain impermeable to trypan blue.
Induction of metallothionein and methallothionein mRNA in rainbow-trout liver following cadmium treatment
Authors: Bonham Keith , Gedamu Lashitew
Published: February 2005

A low-molecular-weight cadmium-binding protein was induced in the livers of rainbow trout (Salmo gairdnerii) following a series of intraperitoneal injections of cadmium chloride. The subsequent purification and amino acid analysis of this protein showed it to be a true metallothionein. As in higher organisms, two major forms of metallothionein appeared to be present in the liver following cadmium treatment. Following a similar induction procedure total RNA was also isolated and shown to contain high levels of metallothionein-mRNA activity when assayed in a wheat-germ cell-free translation system. This activity was present in the Poly-A+-containing fraction of the total RNA. The bulk of this mRNA activity was shown to be in the 8–10S region of a sucrose gradient.
Inhibition of peptidoglycan synthesis of Streptococcus faecium ATCC 9790 and Streptococcus mutans BHT by the antibacterial agent dodecyl glycerol
Authors: Ved H. S. , Gustow Evan , Pieringer Ronald A.
Published: February 2005

Dodecyl glycerol inhibits the synthesis of the peptidoglycans of Streptococcus faecium ATCC 9790 and Streptococcus mutans BHT. This metabolic regulation represents the second known mode by which dodecyl glycerol expresses antibacterial activity. The first mode of action of dodecyl glycerol was shown to stimulate autolysin activity which degrades cell-wall peptidoglycan (Ved HS, Gustow E, Mahadevan V and Pieringer RA, 1984, J. Biol. Chem.259, 8115–8121).
A role for intracellular calcium and calmodulin in the release of triiodothyronine from human thyroid-cell monolayer cultures
Authors: Ollis C. A. , Davies R. , Munro D. S. , Tomlinson S.
Published: February 2005

Human thyroid cells in monolayer responded to acute stimulation by TSH with an increase in the secretion of T3. This process appeared to be dependent on a rise in the cytosolic calcium concentration since the antagonist of intraceliular calcium mobilization, TMB-8, was found to inhibit the release of T3 in response to TSH. The importance of intracellular calcium was further shown using the agent veratridine which increases the free calcium level within cells; veratridine potentiated the stimulation of T3 secretion by TSH and itself stimulated the release of T3 to a level higher than that seen in the presence of TSH alone. The calcium ionophore A23197 produced a biphasic effect on T3 secretion from human thyroid monolayers; at low concentrations, A23187 caused a decrease in both unstimulated and TSH-stimulated T3 secretion but above a concentration of 1 μM, T3 secretion was increased. The calmodulin antagonist W7 was found to inhibit T3 release in response to TSH, indicating a role for calmodulin in mediating the effects of intracellular calcium on T3 secretion.
Influenza-C-virion-associated RNA-dependent RNA-polymerase activity
Authors: Nagele Arno , Meier-Ewert Herbert
Published: February 2005

The addition of detergent-solubilized influenza C virus to a reaction mixture containing ATP, CTP, GTP, [3H]UTP, and Mg2+ leads to the synthesis of an acid-insoluble, radioactive product) which is ribonucJease-sensitive. The dinucleoside monophosphate ApG clearly enhances the reaction rate, a fact which indicates that influenza C viruses follow the same strategy of transcription as influenza A and B viruses, the other members of the orthomyxovirus family.
Characterization of RNA transcripts and virally coded proteins synthesized in mouse fibroblasts transfected with hepatitis B DNA: HBeAg synthesis in HBcAg-negative cells with active core-antigen genes
Authors: Price Peter , Ostrove Steven , Flordellis Christos , Sells Mary Ann , Thung Swan , Gerber Michael , Christman Judith , ACS George
Published: February 2005

A line of mouse cells expressing hepatitis B virus (HBV) surface and ‘e’ antigens identical in their physico-chemical properties to antigens from patients infected with HBV was isolated after transfection of 3T3 ceils with cloned HBV DNA. The studies reported here indicate that the ceils contain uninterrupted copies of the entire HBV genome which are unmethylated on CCGG sites and have no gross deletions or rearrangements. The entire core region is transcribed into polyadenylated RNAs large enough to serve as messengers for production of viral core antigen (HBcAg) yet no HBcAg can be detected. This suggests that the ceils produce a primary translation product copied from the HBcAg messenger which either cannot assume the proper configuration for display of HBcAg determinants or is rapidly converted to HBeAg by proteolysis.
Tyrosinase activity in primary cell culture of amelanotic melanoma cells
Authors: Słomiński A. , Scisłowski P. W. D. , Bomirski A.
Published: February 2005

After transfer of the Ab amelanotic melanoma cells from in vivo to in vitro growth conditons tyrosinase activity in their soluble fraction rapidly increased. This increase lasted to the middle of the logarithmic phase of growth and was followed by a decrease of tyrosinase activity, which was accompanied by accumulation of melanin in the cells. Calf serum stimulated simul-taneously tyrosinase activity, melanin synthesis, and proliferation of the melanoma ceils. Acrylamide-gel electrophoresis patterns of soluble tyrosinase from the Ab melanoma cells cultured in vitro consisted of two bands, similarly as soluble tyrosinase from the Ma melanotic melanoma cells freshly isolated from solid tumors.
A facile method for the isolation of porcine heart mitochondrial malate dehydrogenase by affinity elution chromatography on Procion Red HE3B
Authors: Smith Keith , Sundaram Trichur K.
Published: February 2005

A quick, simple method has been devised for isolating pig heart mitochondrial malate dehydrogenase in apparently homogeneous state and good yield. It entails the adsorption of the enzyme to agarose-linked Procion Red HE3B and specific elution of a ternary complex consisting of the malate dehydrogenase, NAD+, and L-malate.
Inhibition of lipogenesis by vasopressin and angiotensin II in glycogen-depleted hepatocytes
Authors: Palmer T. Norman , Caldecourt Margaret A. , Watts David I. , Sugden Mary C.
Published: February 2005

Vasopressin and angiotensin II inhibited lipogenesis (measured with 3H2O) in hepatocytes from fed rats. Inhibition was also observed with hepatocytes from fed rats which had been depleted of glycogen in vitro and incubated with lactate + pyruvate (5 mM + 0.5 mM) as substrates. The inhibitory actions of the hormones are therefore independent of hormone-mediated changes in glycogenolytic or glycolytic flux from glycogen, and thus the site(s) of hormone action must be subsequent to the formation of lactate. (-)Hydroxycitrate, a specific inhibitor of ATP-citrate lyase, decreased lipogenesis in hepatocytes from fed rats incubated with lactate + pyruvate by approx. 51% but had little effect on lipogenesis in glycogen-depleted hepatocytes similarly incubated. There was parallel inhibition of incorporation of 14C from [U-14C]lactate into fatty acid and lipogenesis as measured with 3H2O in each case. Thus depletion of glycogen, or conceivably the process of glycogen-depletion (incubation with dibutyryl cyclic AMP) causes a change in the rate-determining step(s) for lipogenesis from lactate. Vasopressin and angiotensin II also decreased lipogenesis and incorporation of 14C into fatty acids in glycogen-depleted hepatocytes provided with [U-14C]proline as opposed to [U-14C]-lactate. However, proline-stimulated lipogenesis was inhibited by (-)hydroxycitrate, and proline-stimulated lipogenesis and incorporation of 14C from [U-14C]-proline were not decreased in parallel by this inhibitor (inhibition of 52% and 85% respectively). It is inferred that lactate and proline stimulate lipogenesis by different mechanisms and incorporation of 14C from [U-14C]proline and [U-14C]lactate into fatty acid occurs via different routes. (-)Hydroxycitrate diminished the inhibitory effects of the hormones in the presence of either lactate or proline, suggesting that flux through ATP-citrate lyase is important for the hormone response.
Reorganisation of peripheral actin filaments as a prelude to exocytosis
Authors: Burgoyne Robert D. , Cheek Timothy R.
Published: February 2005

Evidence is presented, from studies on the adrenal chromaffin cell, that reorganisation of the cortical actin network is necessary to allow granules to reach exocytotic sites in stimulated cells. This reorganisation may involve changes in actin filament cross-linking, assembly and interactions with secretory granule and plasma membranes. The possibility is discussed that cytoskeletal elements including the membrane-binding proteins caldesmon, p70 and p36 may be involved in granule-plasmalemmal interactions immediately prior to exocytosis.
Alpha 1-antitrypsin deficiency—A defect in secretion
Authors: Foreman R. C.
Published: February 2005

A naturally occurring point mutation in the human alpha 1-antitrypsin gene leads to the synthesis of a variant of the protein which is poorly secreted from hepatocytes. This Z; mutation codes for a glutamic acid to lysine substitution at residue 342 in the polypeptide chain. The mutant protein is correctly translocated into the lumen of the endoplasmic reticulum and core glycosylated but inefficiently transported beyond the ER compartment. Experiments using Xenopus oocytes as a surrogate secretory cell show that abberant secretion of the variant is not confined to hepatocytes and glycosylation of the polypeptide is not obligatory for the block in secretion. Site-directed mutagenesis can be used to examine the effect of natural mutations on protein structure and the relationship between structure and intraceltular transport.