bluuebunny/crossref_metadata_2025 huggingface dataset:
Binary flash‐induced oscillations of [14C]DCMU binding to the photosystem II acceptor complex
Authors: Laasch Henrik , Urbach Wolfgang , Schreiber Ulrich
Published: July 2002

Binding of radioactively‐labelled DCMU to spinach chloroplast membranes is determined following pre‐illumination by single turnover saturating light flashes. When binding is assayed rapidly following inhibitor addition (< 40 s) distinct binary oscillations of [14C]DCMU binding can be observed. By dark‐adapted samples or those, following an even number of flashes, more inhibitor is bound than after one or an odd number of flashes. During longer incubation times (2 min), [14C]DCMU binding becomes independent of flash preillumination. Comparison of the [14C]DCMU binding kinetics following one flash and the kinetics of the DCMU‐induced increase of chlorophyll fluorescence rise reveals a substantial amount of binding which is not accompanied by a corresponding fluorescence rise. These data are discussed within the framework of the ‘inhibitor‐plastoquinone competition model’ [FEBS Lett. (1981) 126, 277–281] and with reference to DCMU binding data derived from fluorescence measurements [Biochim. Biophys. Acta (1982) 682, 245–253].
Solubilization and partial characterization of adenosine binding sites from rat brainstem
Authors: Nakata Hiroyasu , Fujisawa Hitoshi
Published: July 2002

Binding sites for adenosine were solubilized from rat brainstem membranes with either sodium cholate, sodium deoxycholate or 3‐[3‐cholamidopropyl)dimethyl‐ammonio]‐1‐propanesulfonate. About 30% of the binding activity were released by these detergents as assayed by [3H]phenylisopropyladenosine (PIA) binding. Specific [3H]PIA binding to the solubilized fraction was saturable and was found to be a monophasic saturation profile. In contrast, [3H]PIA binding sites. By gel filtration on a Sepharose CL‐6B biphasic profile suggesting the presence of two binding sites. By gel filtration on a Sepharose CL‐6B column, the adenosine binding site—detergent complex was estimated to have app. M
r 280 000 and r
s = 5.4 nm.
The glycopeptide domain of the rat vasopressin precursor
Authors: Chauvet M.T. , Chauvet J. , Acher R.
Published: July 2002

The vasopressin precursor is composed of 3 domains, namely vasopressin, MSEL‐neurophysin and a glycopeptide. Processing occurs during axonal transport from hypothalamus to neurohypophysis from which the 3 fragments can be isolated. The glycopeptide fragment of the rat vasopressin precursor has been purified and sequenced. Despite the fact that rat MSEL‐neurophysin is shortened (93 residues instead of 95 for other mammals), rat glycopeptide has 39 residues, as do the other mammalian glycopeptides, suggesting a similar processing. Fifteen substitutions are however observed when compared to ox glycopeptide. The C‐terminal part of MSEL‐neurophysin (residues 77–93) and the glycopeptide are encoded by the same exon and the homologies when compared with their bovine counterparts are 58% and 62% respectively. In contrast, the central part of rat MSEL‐neurophysin (residues 10–76), which is encoded by a separate exon, displays 96% of homology; vasopressin and the N‐terminal part of MSEL‐neurophysin (residues 1–9), encoded by a third exon, are nearly invariant.
Schiff's base formation in the lens protein γ‐crystallin
Authors: Wistow G. , Alligood J. , Shinohara T. , Somers R.
Published: July 2002

Uniquely among the soluble lens‐specific proteins, γ‐crystallin is capable of binding the strongly chromophoric aldehyde retinal. a role for γ‐crystallin in protecting lens components from toxic aldehydes resulting from membrane oxidation is proposed and a molecular model of the probable interaction site is presented. The sequence of a tetrapeptide at this site is identical to that of the retinal binding site of bacteriorhodopsin.
Carboxypeptidase activity in the insulin secretory granule
Authors: Docherty Kevin , Hutton John C.
Published: July 2002

Carboxypeptidase activity was studied in subcellular fractions from a transplantable rat insulinoma and found to be localised principally in the insulin secretory granule. The activity, which was specific for peptide substrates with C‐terminal basic amino acids, appeared to be a single enzyme with M
r 54 000. This enzyme differed with respect to size and pH optimum from other basic amino acid‐specific carboxypeptidases, such as carboxypeptidases B and N, and may be a secretory granule‐specific enzyme involved in propolypeptide processing.
The structure of DNA binding protein II at 6 Å resolution
Authors: Tanaka Isao , White Stephen W. , Appelt Krzysztof , Wilson Keith S. , Dijk Jan
Published: July 2002

The structure of DNA binding protein II from Bacillus stearothermophilus is described at 6 Å resolution. The molecule exists as the dimer in our crystals, and there are 3 independent dimers related by non‐crystallographic symmetry in the unit cell. The dimer is compact and globular with dimensions of about 32 × 35 × 39 Å3.
A transposon‐like DNA fragment interrupts a Physarum polycephalum histone H4 gene
Authors: Wilhelm Marcelle L. , Wilhelm François-Xavier
Published: July 2002

A recombinant DNA library was screened for histone H4 genes using a sea urchin probe. One recombinant was analysed by restriction enzyme mapping and Southern blotting. The complete DNA sequence of the H4 histone locus was determined. An 86 base pair interrupting sequence was found within the histone H4 coding sequence. The inserted DNA fragment has some characteristics of a transposable element.
Lack of inhibition of carrot colchicine binding activity by podophyllotoxin
Authors: Okamura Shoji , Kato Tomoko , Nishi Arasuke
Published: July 2002

The binding of [3H]colchicine to carrot cell extract was not inhibited by an excess amount of podophyllotoxin. Under the same experimental condition, porcine brain tubulin almost completely lost its [3H]colchicine binding activity. The components in the carrot cell extract did not affect the interaction of brain tubulin and podophyllotoxin.
Characterization of a monoclonal antibody to human sex hormone binding globulin
Authors: Hammond G.L. , Robinson P.A.
Published: July 2002

We have produced a monoclonal hybridoma cell line (S1B5) that secretes an IgG2α immunoglobulin with a high affinity (K
d 0.38 × 10−11 M) for 125I‐labelled sex hormone binding globulin (SHBG), and which will specifically immunoprecipitate SHBG from serum. The antibody is produced in high titre in culture medium and ascites fluid, and can be purified to apparent homogeneity by protein A affinity chromatography. When examined by isoelectrofocussing, a characteristic series of bands, which bind 125I‐SHBG, are observed at pH 8.5–9. Competitive, superimposable displacement of 125I‐SHBG from the antibody is achieved with dilutions of human, chimpanzee and gorilla sera at comparable SHBG concentrations. Partial cross‐reaction is observed with sera from other Old World primates, but not with sera from New World monkeys or any other vertebrate species studied.
Control of intermediate filament protein synthesis by cell‐cell interaction and cell configuration
Authors: Ben-Ze'ev Avri
Published: July 2002

The expression of cytokeratins and vimentin was investigated in epithelial cells under conditions of varied cell spreading and cell‐cell contact. When extensive cell‐cell contact was achieved in dense monolayer cultures, or in suspension in multicellular aggregates, the cells synthesized high levels of cytokeratins and low levels of vimentin. In contrast, sparse monolayer and suspension cultures, with minimal cell‐cell contact, synthesized low levels of cytokeratins and high levels of vimentin. The ratio of cytokeratin to vimentin synthesis was independent of the cell cycle and was also reflected at the level of mRNA translational activity in vitro. Thus control of cytokeratin synthesis involves cell‐cell contact, while vimentin synthesis responds to cell shape changes.
Nature of the interaction between Ricinus communis agglutinin and blood cells
Authors: Turpin Elisabeth , Frénoy Jean-Pierre , Goussault Yves
Published: July 2002

Ricinus communis agglutinin
Human lymphocyte
Lectin‐cell surface interaction
Conversion of 1‐aminocyclopropane‐1‐carboxylic acid to ethylene in submitochondrial particles isolated from plants
Authors: Vinkler Chana , Apelbaum Akiva
Published: July 2002

Conversion of 1‐aminocyclopropane‐1‐carboxylic acid (ACC) to ethylene was studied in submitochondrial particles (SMP) which were prepared by sonication of the mitochondrial fraction isolated from 7‐day‐old etiolated pea (Pisum sativum var. Kelvedon Wonder) seedlings. The reaction was enhanced by the addition of Mn2+ and had a maximal rate at pH 8.0. Conversion of ACC to ethylene was inhibited under anaerobic conditions and by the addition of KCN, EDTA, NaN3, n‐propyl gallate and CoCl2. Addition of the uncouplers 2,4‐DNP, CCCP and FCCP, however, did not inhibit the reaction. Structural analogs of ACC inhibited ACC conversion to enthylene by SMP. The structural analog of methionine, α‐keto‐γ‐methylthiobutyric acid (KMB), was converted to ethylene by SMP at a rate which was only about 2% that of ACC conversion to ethylene.
Interaction of EcoRII restriction and modification enzymes with synthetic DNA fragments
Authors: Yolov A.A. , Gromova E.S. , Romanova E.A. , Oretskaya T.S. , Oganov A.A. , Buryanov Ya.I. , Shabarova Z.A.
Published: July 2002

Interaction of EcoRII restriction endonuclease with a set of synthetic concatemer DNA duplexes with natural and modified sites for this enzyme has been studied. DNA duplexes with repeated natural sites are cleaved by EcoRII. Substitution of central AT‐pair in the recognition site for a non‐complementary TT‐ or AA‐pair reduces the rate of cleavage, this effect being much more pronounced in the last case. Absence of site flanking in one strand from the 5′‐terminus also results in very slow cleavage. The results obtained testify to the interaction of EcoRII with both strands of the substrate.
The effect ofuncouplers (F)CCCP and NH4Cl on the kinetics of the flash‐induced P515 electrochromic bandshift in spinach chloroplasts
Authors: Peters R.L.A. , van Kooten O. , Vredenburg W.J.
Published: July 2002

The effect of uncouplers of photophosphorylation on the kinetics of the flash‐induced P515 electrochromic bandshift was investigated in dark‐adapted chloroplasts. It was found that the presence of low concentrations of carbonyl cyanide p‐trifluoromethoxyphenylhydrazone (FCCP) and carbonyl cyanide m‐chloro‐phenylhydrazone (CCCP) resulted in the selective suppression of the slow P515 absorbance change (reaction 2), whereas the fast change (reaction 1) was not influenced. In contrast, high concentrations of NH4Cl did not alter the P515 response with respect to reactions 1 and 2. These results indicate that reaction 2 is specifically sensitive towards uncouplers which exert their function as a proton carrier in the lipophilic phase of the membrane.
On the role of membrane integrity in the conversion of 1‐aminocyclopropane 1‐carboxylic acid to ethylene in carnation petals
Authors: Borochov Amihud , Adam Zach
Published: July 2002

The reaction converting 1‐aminocyclopropane 1‐carboxylic acid (ACC) to ethylene in plants is independent of cell or membrane integrity. Both intact and detergent‐solubilised membrane fractions can readily convert ACC to ethylene. The reaction catalysed by the solubilised enzyme is inhibited by 100 μM 2,4‐dinitrophenol. ATP, even at very low concentrations, totally inhibits the reaction. The results would appear to invalidate a previously hypothesised model for this reaction.
DNA topoisomerase activities in concanavalin A‐stimulated lymphocytes
Authors: Taudou Georges , Mirambeau Gilles , Lavenot Catherine , der Garabedian Arsène , Vermeersch Jacqueline , Duguet Michel
Published: July 2002

Topoisomerase activities have been measured in nuclear extracts of concanavalin A‐stimulated lymphocytes. In parallel with the wave of DNA synthesis, type II topoisomerase activity was considerably increased. After 72 h treatment, this activity was stimulated approx. 20‐fold over the activity in untreated cells. In contrast, type I topoisomerase was poorly stimulated after 24 h treatment, and 4‐5‐fold after 72 h. These findings, together with our previous results on regenerating rat liver, suggest a major role of topoisomerase II in DNA replication.
Enhancement of O2− generation and tumoricidal activity of murine macrophages by a monosaccharide precursor of Escherichia coli lipid A
Authors: Amano Fumio , Nishijima Masahiro , Akagawa Kiyoko , Akamatsu Yuzuru
Published: July 2002

The effects of a monosaccharide precursor of Escherichia coli lipid A (lipid X) on murine macrophages were studied. Lipid X is a diacylglucosamine 1‐phosphate bearing β‐hydroxymyristoyl groups at positions 2 and 3. Lipid X, as well as lipopolysaccharide and lipid A, enhanced O2
− generation in mouse peritoneal macro‐phages and a macrophage‐like cell line, J774.1, and further induced the tumor‐cytotoxic activity of peritoneal macrophages. Elimination of a 1‐phosphate or 3‐O‐β‐hydroxymyristoyl group from lipid X completely abolished these effects, suggesting that both 1‐phosphate and 3‐O‐β‐hydroxymyristoyl groups are essential for the elevated O2
− generation and induction of turmoricidal activity due to lipid X.
H+/ion antiport as the principal mechanism of transport systems in the vacuolar membrane of the yeast Saccharomyces carlsbergensis
Authors: Okorokov L.A. , Kulakovskaya T.V. , Lichko L.P. , Polorotova E.V.
Published: July 2002

The secondary transport systems of the yeast vacuolar membrane have been investigated by (i) the method of radioactive isotopes ([14C]arginine); (ii) activation of H+‐ATPase by cations (Cat+), when the enzyme is under H+ control and (iii) measurement of changes in the proton gradient (Δ pH) and membrane potential (E
m) due to the supposed substrates of the transporters. The main mechanism of cation transport across the yeast tonoplast is probably H+/Cat+ antiport. The apparent K
m of antiporters for Ca2+, Mg2+ Mn2+, Zn2+ and Pi are 0.06, 0.3, 0.8, 0.055‐0.17 and 1.5mM, respectively.
Selective labeling of beef heart cytochrome oxidase subunit III with eosin‐5‐maleimide
Authors: Müller Michele , Azzi Angelo
Published: July 2002

Cytochrome c oxidase has been isolated from beef heart mitochondria and labeled with the fluorochrome eosin‐5‐maleimide (EMA) after pretreatment with mersalyl. On SDS‐polyacrylamide gels, EMA fluorescence and absorption occurred at a single band corresponding to subunit III. Since only Cys 115 of the two cysteinyl residues of subunit III had been shown to be reactive towards water‐soluble SH‐reagents, it was concluded that this residue was the one labeled by EMA. The EMA/enzyme ratio was about 1. Gel filtration experiments have shown that upon treatment with dicyclohexylcarbodiimide, subunit III was loosened from the complex; this result suggests that the inhibitory effect of dicyclohexylcarbodiimide on the H+‐translocation activity may be related to such a phenomenon.
Degradation of somatomedins by the thioredoxin system
Authors: Enberg Gösta , Holmgren Arne
Published: July 2002

Insulin
Degradation
Thioredoxin
Insulin‐like growth factor I
Insulin‐like growth factor II
Effect of depolarizing concentrations of potassium on calcium uptake and metabolism in rat liver
Authors: Taylor Wayne M. , van de Pol Erika , van Helden Dirk F. , Reinhart Peter H. , Bygrave Fyfe L.
Published: July 2002

Liver
Potassium depolarization
Glycogenolysis
Calcium antagonist
Low level transport of IgA to bile via the asialoglycoprotein receptor
Authors: Schiff J.Michael , Underdown Brian J.
Published: July 2002

Immunoglobulin A
Asialoglycoprotein receptor
Secretory component
Receptor‐mediated endocytosis
Transport to bile
Protein sorting
Structural features of crystal‐forming proteins produced by Bacillus thuringiensis subspecies israelensis
Authors: Chestukhina G.G. , Zalunin I.A. , Kostina L.I. , Bormatova M.E. , Klepikova F.S. , Khodova O.M. , Stepanov V.M.
Published: July 2002

Bacillus thuringiensis ssp. israelensis δ‐Endotoxin
Entomocidal crystal
Insecticide
Mosquito
The anti‐oestrogen drug tamoxifen is an elongation inhibitor of eukaryotic protein biosynthesis
Authors: Guille Matthew J. , Arnstein Henry R.V.
Published: July 2002

The drug tamoxifen is widely used in the chemotherapy of breast cancer but its action is not explained completely by its anti‐oestrogen properties. We now present evidence indicating that it is also a potent inhibitor of eukaryotic protein synthesis as demonstrated in Xenopus oocytes, intact reticulocytes and reticulocyte lysates. The inhibition affects general protein synthesis, is transient in oocytes and not reversed by oestrogen. The drug appears to act by inhibiting polypeptide chain elongation. This action of tamoxifen is independent of oestrogen receptors and may explain its therapeutic effectiveness in oestrogen‐independent tumours.
Inhibition of acetylcholinesterase from electric eel by (−)‐ and (+)‐physostigmine and related compounds
Authors: Brossi A. , Schönenberger B. , Clark O.E. , Ray R.
Published: July 2002

Physostigmine (Eserine)
Eseroline
Cholinesterase
Interaction of GTP‐binding proteins with calmodulin
Authors: Asano Tomiko , Ogasawara Nobuaki , Kitajima Satoko , Sano Mamoru
Published: July 2002

Two GTP‐binding proteins (Gi and Go), which were the substrates for islet‐activating protein, pertussis toxin, were purified from bovine cerebral cortical membranes. Both Gi and Go completely inhibited calmodulin‐stimulated cyclic nucleotide phosphodiesterase activity. The same concentrations of these proteins, however, had no appreciable effect on the basal phosphodiesterase activity. The isolated Giα and βγ subunits of GTP‐binding proteins were potent inhibitors of the calmodulin‐stimulated phosphodiesterase activity, but Goα was very weak. Therefore, the βγ subunits were likely to be the major active molecules in the brain membranes. GTP‐binding proteins were shown to bind directly to calmodulin in a Ca2+‐dependent manner by a gel permeation binding experiment.
Involvement of the Ca2+‐dependent K+ channel activity in the hyperpolarizing response induced by epidermal growth factor in mammary epithelial cells
Authors: Enomoto Kohichi , Cossu M.Franca , Maeno Takashi , Edwards Charles , Oka Takami
Published: July 2002

Epidermal growth factor (EGF) induces a hyperpolarizing response of 5–20 mV amplitude in mouse mammary epithelial cells in culture. The amplitude of the hyperpolarizing response was reduced by more than 60% within several minutes after addition of blockers of voltage and/or Ca2+‐dependent K+ channels such as tetraethylammonium (7 mM) or quinine (0.29 mM). Both nifedipine (0.15 mM), a blocker of the Ca2+ channel, and ruthenium red (2 mM), an inhibitor of the Ca2+‐binding site, also reduced the amplitude of the hyperpolarizing response by more than 60%. The Ca2+ ionophore, A23187 (3.8 μM), induced a large hyperpolarization, which was 25–40 mV and lasted about 3 min. These data suggest that activity of the Ca2+‐dependent K+ channel was involved in the EGF‐induced hyperpolarizing response of the mammary epithelial cells.
Isolation and amino acid sequence of a mating pheromone produced by mating type α cells of Saccharomyces exiguus
Authors: Sakurai Akira , Tanaka Hiroko , Esumi Yasuaki , Takahashi Nobutaka , Hiscatomi Taisuke , Yanagishima Naohiko , Banno Isao
Published: July 2002

A peptide, termed αse pheromone, was isolated as a mating pheromone from culture filtrate of mating type a cells of Saccharomyces exiguus. The peptide showed both agglutinability‐inducing activity to a cells of S. cerevisiae and shmoo‐inducing action to a cells of S. cerevisiae, S. kluyveri and S. exiguus. The amino acid sequence of αse pheromone was determined as H‐Trp‐His‐Trp‐Leu‐Arg‐Leu‐Ser‐Tyr‐Gly‐Gln‐Pro‐Ile‐Tyr‐OH by mass spectrometry, sequence analysis and enzymatic digestion.
Partial molecular characterization of endothelial cell mitogens from human brain: acidic and basic fibroblast growth factors
Authors: Gautschi Peter , Fràter-Schröder Marijke , Böhlen Peter
Published: July 2002

Two endothelial cell growth factors have been isolated from human brain extracts by a procedure involving heparin‐Sepharose affinity chromatography and reverse‐phase HPLC. On the basis of molecular size, amino acid composition and extended amino‐terminal sequences, the two proteins are structurally closely related to bovine acidic and basic fibroblast growth factors (aFGF, bFGF). The N‐terminal sequences of human and bovine aFGF diner in two positions while those for bFGF are indistinguishable. Human aFGF is microheterogenous: in addition to aFGF two N‐terminally truncated forms lacking the first and the seven first amino acids, respectively, were characterized. Human and bovine mitogens possess similar mitogenic activities.
Ca2+‐dependent inactivation of acetylcholine receptors by an endogenous transglutaminase
Authors: Hucho F. , Bandini G.
Published: July 2002

The nicotinic acetylcholine receptor (nAChR) from Torpedo californica and T. marmorata electric tissue polymerises irreversibly when DTE and Ca2+ are added to receptor‐rich membranes. The polymerisation is time‐dependent and complete within 3 h at 30°C. It can be completely prevented by EGTA or the transglutaminase inhibitor cystamine. Transglutaminase activity can also be monitored with the exogenous substrates [3H]putrescine and dimethylcasein. This assay can also be inhibited by EGTA or cystamine.
Insulin but not phorbol ester treatment increases phosphorylation of vinculin by protein kinase C in BC3H‐1 myocytes
Authors: Cooper Denise R. , de Ruiz Galaretta Carlos M. , Fanjul Luisa F. , Mojsilovic Ljubomir , Standaert Mary L. , Pollet Robert J. , Farese Robert V.
Published: July 2002

Insulin was found to increase protein kinase C activity in BC3H‐1 myocytes as determined by in vitro phosphorylation of both a lysine‐rich histone fraction (histone III‐S) and vinculin. TPA treatment for 20 min or 18 h provoked an apparent loss of histone‐directed but not vinculin‐directed phosphorylation by cytosolic C‐kinase. Thus, chronic TPA‐induced ‘desensitization’ or ‘depletion’ of cellular protein kinase C is more apparent than real, and is not a valid means for evaluating the role of C‐kinase in hormone action.
A putative internal promoter in the 16 S/23 S intergenic spacer of the rRNA operon of archaebacteria and eubacteria
Authors: Mankin A.S. , Skripkin E.A. , Kagramanova V.K.
Published: July 2002

The existence of the internal promoter Pi in the 16 S/23 S intergenic spacers of the rRNA operons of an eubacterium Escherichia coli and archaebacterium Halobacterium halobium is proposed. The possible functional significance of these promoters is discussed.
Neomycin inhibits K+ ‐ and veratridine‐stimulated noradrenaline release in rat brain slices and rat brain synaptosomes
Authors: Diamant Sophia , Avraham Boaz , Atlas Daphne
Published: July 2002

The possible involvement of phosphoinositides' turnover in the process of neurotransmitter release in the central nervous system (CNS) was studied using rat brain slices and synaptosomes. A depolarizing concentration of potassium chloride (25 mM) induces an 8.6 ± 0.4% increase of [3H]noradrenaline ([3H]NA) fractional release in cerebral cortical slices above spontaneous release, and 15 mM KCl induces a 3‐fold increase of [3H]NA release in rat brain synaptosomes. Neomycin, an aminoglycoside which binds phosphoinositides, inhibits the potassium‐induced release in cortical slices with an IC50 = 0.5 ± 0.07 mM and with IC50 = 0.2 ± 0.03 mM in synaptosomes. Veratridine, a veratrum alkaloid which increases membrane permeability to sodium ions and causes depolarization of neuronal cells, induces a net 13.4 ± 0.3% increase of [3H]NA fractional release above spontaneous release in cortical slices. In analogy to K+ stimulation, neomycin inhibits the veratridine‐stimulated release in cortical slices with an IC50 = 0.65 ± 0.1 mM. It appears that the recycling of phospoinositides, which is necessary for Ca2+ mobilization, participates in the Ca2+‐dependent induced neurotransmitter release in the central nervous system.
Identification of free radicals in myocardial ischemia/reperfusion by spin trapping with nitrone DMPO
Authors: Arroyo Carmen M. , Kramer Jay H. , Dickens Benjamin F. , Weglicki William B.
Published: July 2002

The spin trapping ESR technique was applied to investigate oxygen‐derived radicals in ischemic and postischemic rat hearts. Using 5,5′‐dimethyl‐1‐pyrroline‐N‐oxide, carbon‐centered radicals were identified during ischemia and oxy‐radical adducts (superoxide anion radical, O.−
2 and hydroxyl radicals, .OH) in postischemic rat heart. The formation of these spin adducts was inhibited by superoxide dismutase, suggesting that superoxide plays a role in the adducts' formation. The results demonstrate that oxygen derived free radicals are important byproducts of abnormal oxidative metabolism during myocardial ischemic and reperfusion injuries.
Immunoaffinity‐purified opiate receptor specifically binds the δ‐class opiate receptor ligand, cis‐(+)‐3‐methylfentanylisothiocyanate, SUPERFIT
Authors: Carr Daniel J.J. , DeCosta Brian , Jacobson Arthur E. , Bost Kenneth L. , Rice Kenner C. , Blalock J.Edwin
Published: July 2002

Using an antibody generated against the opiate receptor on NG108‐15 cells, we recently purified the putative receptor from this hybrid cell line. We herein report that the purified receptor complex specifically binds tritiated cis‐(+)‐3‐methylfentanylisothiocyanate (SUPERFIT), with the predominant binding associated with a 58 kDa polypeptide chain. Consistent with these findings is the in situ labeling of a 58 kDa protein with [3H]SUPERFIT on NG108‐15 cells.
Saccharomyces cerevisiae mRNA populations of different intrinsic stability in unstressed and heat shocked cells display almost constant m7GpppA:m7GpppG 5′‐cap structure ratios
Authors: Piper Peter W. , Curran Brendan , Davies Wayne , Hirst Karen , Seward Kevin
Published: July 2002

The half‐lives of mRNAs in yeast vary from about 1 to over 100 min. While mRNA stabilities must strongly influence overall gene expression in this organism, very little is known about how they are determined. Labellings of yeast cells were conducted to investigate whether the 5′‐cap structures of yeast mRNAs might influence their stability. Variation of the pulse‐labelling period from 7.5 min to 120 min did not have any major influence on the relative labelling of m7GpppA (A cap) and m7GpppG (G cap) in total polyadenylated RNA. Whether an mRNA has the A cap or the G cap does not therefore have a marked effect on its stability. During the heat shock response the relative labelling of A caps to G caps in total polyadenylated RNA also does not fluctuate appreciably. This indicates that cap structure alone does not determine the destabilisation of non‐heat shock mRNAs and stabilisation of heat shock mRNAs during this stress response.
Gangliosides stimulate dome formation in cultured canine kidney epithelial cell line (MDCK)
Authors: Rodrig N. , Osanai T. , Iwamori M. , Nagai Y.
Published: July 2002

The effect of exogenous gangliosides on the occurrence of domes in MDCK cell cultures was investigated in view of the involvement of both dome formation and gangliosides in cell growth, differentiation and transepithelial transport. Dome formation was increased by gangliosides in medium free of fetal calf serum. Among the gangliosides tested, GM3 and GD3 isolated from porcine kidney were most active, increasing the dome number 12–17‐fold. Since gangliosides from kidney were more active than those from brain and erythrocytes, the hydrophobic moiety as well as sialic acid might be involved in this activity. These results indicate that tissue‐specific molecules of gangliosides function as inducers or mediators of dome formation. The mechanism probably involves adenylate‐ cyclase or another transmembrane biosignal‐transducing system.
Comparative optically detected magnetic resonance studies of mammalian phospholipase A2‐lipid interactions
Authors: Mao Su-Yau , H. Maki August , de Haas Gerard H.
Published: July 2002

A major difference between porcine and bovine pancreatic phospholipase A2 (PA2) is the relatively low affinity of the bovine enzyme for lipid‐water interfaces. We have investigated the binding of porcine, bovine, and equine PA2 to n‐hexadecylphosphocholine (C16‐PC) micelles using optically detected magnetic resonance (ODMR) spectroscopy. The zero field splittings (ZFS) of the single Trp‐3 residue undergo significant changes upon binding of PA2 to C16‐PC micelles. ZFS titrations of PA2 vs C16‐PC indicate that porcine and equine enzymes have similar binding affinity and stoichiometry, while bovine PA2 binds much more weakly to the lipid‐water interfaces. This may be attributed to the differences in the amino acid composition and the conformation of the binding sites for lipid‐water interfaces of these enzymes.
Cyclic AMP‐like effects of polyamines on phosphatidylcholine synthesis and protein phosphorylation in human promyelocytic leukemia HL60 cells
Authors: Kiss Zoltan , Deli Eva , Kuo J.F.
Published: July 2002

Spermine or putrescine increased cAMP levels through a catalase‐sensitive mechanism, resulting in, most notably, a dephosphorylation of protein A (M
r 45 000, pI 5.15) and protein B (M
r 45000, pI 4.9) and slightly increased phosphatidylcholine (PC) synthesis in HL60 cells. Exogenous dibutyryl cAMP mimicked the polyamine effects. 12‐O‐Tetradecanoyl phorbol‐13‐acetate (TPA) also promoted the protein dephosphorylation and PC synthesis, the effects augmented by R59022 and mimicked by exogenous 1‐oleoyl‐2‐acetylglycerol. The effects of spermine (or dibutyryl cAMP) and TPA on PC synthesis were synergistic. It was suggested that cAMP‐dependent protein kinase and protein kinase C might mediate, in an independent but interrelated manner, the effects of polyamines and TPA.
The enhanced 32P labeling of CDP‐diacylglycerol in c‐myc gene expressed human kidney cancer cells
Authors: Kubota Yoshinobu , Shuin Taro , Yao Masahiro , Inoue Hiroko , Yoshioka Tohru
Published: July 2002

Correlation between c‐myc gene expression and phosphatidylinositol (PI) metabolism was studied using seven human kidney cancer cell lines. We found that the exceptional incorporation of 32P into CDP‐diacyl‐glycerol (CDP‐DG) was observed in only two cell lines, in which c‐myc expression was increased among seven cell lines tested. In these two cell lines, PI was also labeled. The other five cell lines indicated the accumulation of radioactive PI, whereas CDP‐ DG was unlabeled.
Relationship of promagainin to three other prohormones from the skin ofXenopus laevis: A different perspective
Authors: Hunt Lois T. , Barker Winona C.
Published: July 2002

We observed a striking sequence similarity between precursors for promagainin and procaerulein type I (excluding the caerulein peptide region). Additional comparisons of the promagainin precursor with those of other procaeruleins, proxenopsin, and peptide‐Gly‐Leu‐amide revealed that all possess one or more copies of a structurally similar spacer module, from which an amphiphilic spacer peptide is cleaved. Promagainin yields the magainins, spacer peptides with antimicrobial activity; we suggest other spacer peptides may have similar activity. We propose that the genes for the four kinds of hormones were derived from a common ancestral gene through gene and exon duplications and that the procaerulein and proxenopsin genes are mosaic genes in which the original 3′‐ends were replaced by exon shuffling.
Identification of a deletion in the LDL receptor gene A Finnish type of mutation
Authors: Aalto-setälä Katriina , Gylling Helena , Miettinen Tatu , Kontula Kimmo
Published: July 2002

A cDNA probe for the low density lipoprotein (LDL) receptor gene was used to screen DNA samples from 52 unrelated Finnish patients with the heterozygous form of familial hypercholesterolemia (FH) and 51 healthy controls. Southern blot analysis using the restriction enzyme PvuII revealed an abnormal 11 kb (kilo base‐pair) restriction fragment in 16 (31%) of the patients but none of the controls. A more detailed restriction enzyme analysis of the DNA from patients revealed a mutation which apparently is due to an 8 kb deletion extending from intron 15 to exon 18 of the LDL receptor gene. Co‐segregation of FH with the mutated gene was demonstrated in three families. These data are consistent with a ‘founder gene effect’ and support the assumption that recombinant DNA methods may have great impact on the diagnostics of FH in genetically homogeneous populations.
An amphibian two‐domain ‘big’ neurophysin: conformational homology with the mammalian MSEL‐neurophysin/copeptin intermediate precursor shown by trypsin‐Sepharose proteolysis
Authors: Chauvet Jacqueline , Michel Gilles , Chauvet Marie-Thérèse , Acher Roger
Published: July 2002

A ‘big’ frog (Rana esculenta) neurophysin, encompassing sequences homologous to mammalian MSEL‐neurophysin and copeptin, has been passed through a trypsin‐Sepharose column in order to compare its conformation with that of the two‐domain intermediate precursor isolated from guinea pig. Whereas the polypeptide possesses 8 arginine residues, only two cleavages were observed located in a putative inter‐domain sequence (at Arg‐94 and Arg‐114). Because free vasotocin has been isolated from the frog, it is assumed that pro‐vasotocin has a three‐domain conformation similar to that of pro‐vasopressin but processing in amphibians involves only one step rather than two steps as in mammals.
Evidence against a tumour‐specific EcoRI RFLP of the c‐mos locus
Authors: Corell Birgit , Zoll Barbara
Published: July 2002

EcoRI restriction fragment length polymorphisms (RFLP) at the human c‐mos locus were analysed in DNAs of normal individuals and tumour patients. Two alleles with fragment lengths of 2.6 kb (A1) and 5.6 kb (A2) respectively were detected. The allele distribution among the tumour group was similar to that of the control group. No difference was found between the allele frequencies in leucocytes and tumour tissue DNA of the same patients.
Inositol trisphosphate stimulates the release of calcium from intact vacuoles isolated from Acer cells
Authors: Ranjeva R. , Carrasco A. , Boudet A.M.
Published: July 2002

On addition of inositol trisphosphate, intact vacuoles isolated from Acer pseudoplatanus cell suspension cultures release part of their calcium content. The process was specific, dose‐dependent (IC50 = 0.2μM) and was inhibited by an intracellular calcium antagonist. The calcium efflux elicited by inositol trisphosphate increased with the age of the cell suspension cultures, the maximum effect being obtained when the cultures reached the stationary phase. It is suggested that vacuoles play a role as an endocellular calcium store that is responsive to inositol trisphosphate in plants.
NADPH‐dependent metabolism of the ribulose bisphosphate carboxylase/oxygenase inhibitor 2‐carboxyarabinitol 1‐phosphate by a chloroplast protein
Authors: Salvucci Michael E. , Holbrook Gabriel P. , Anderson Joan C. , Bowes George
Published: July 2002

Metabolism of 2‐carboxyarabinitol 1‐phosphate (CA 1‐P), an endogenous inhibitor of ribulose bisphosphate carboxylase/oxygenase, occurs in the light. A soluble protein fraction which metabolized CA 1‐P in the presence of NADPH was isolated from tobacco chloroplasts. A similar fraction from spinach exhibited much lower activity. The activity in tobacco extracts was stable overnight at 4°C but its maintenance during storage required dithiothreitol. The tobacco protein responsible for CA 1‐P metabolism was partially purified by ion‐exchange FPLC of stromal extracts. The requirements for NADPH and dithiothreitol for activity of this protein suggest a mechanism for the light‐dependent control of CA 1‐P levels in plants.
A biphasic nature of the bleomycin‐mediated degradation of DNA
Authors: Strekowski Lucjan , Mokrosz Jerzy L. , Wilson W.David
Published: July 2002

The bleomycin‐mediated digestion of DNA in the presence of ferrous ion, molecular oxygen, and dithiothreitol is characterized by a fast initial reaction, which is followed by a much slower process. The fast degradation is due to the fast activation of the bleomycin‐Fe(II) complex and the subsequent fast reaction of the activated complex with DNA. The rate determining step for the slow process is reactivation of the bleomycin‐Fe(III) complex. The apparent rate constants for both reactions increase with increasing ionic strength. The latter, unusual results are interpreted in terms of inhibition of bleomycin turnover by binding of cationic species with DNA at low ionic strength.
Differential transcription of the bla regulatory region during induction of β‐lactamase in Bacillus licheniformis
Authors: Salerno Anthony J. , Lampen J.Oliver
Published: July 2002

Induction of β‐lactamase (blaP) in Bacillus licheniformis involves the regulatory genes blaI (repressor), blaR1 (coinducer) and R2 (function unknown). Transcription of the bla genes during induction was followed by Northern hybridization. In the first 30 min 2.3‐kb transcripts encoding blaI and blaR1 were present. Subsequently, blaP mRNA and short transcripts encoding only blaI accumulated and reached a peak at 1 h. All bla transcripts turn over rapidly. Active repressor is not required for the burst of blaI‐blaR1 mRNA. The production of blaI‐blaR1 mRNA, and thus of BlaR1, is probably controlled both at initiation of transcription and at a later step in its synthesis and degradation.
Complement C9 is inserted into membranes in a globular conformation
Authors: Marazziti Daniela , Luzio J.Paul , Stanley Keith K.
Published: July 2002

Complement component C9 undergoes a major conformational change during its insertion into a biological membrane from a globular to an extended form. At 0°C a single C9 binds but a membrane attack complex (MAC) is not formed. We show that the C9 bound at 0°C is accessible to the intracellular space and sensitive to trypsin digestion, suggesting that C9 inserts in its globular state and requires an elevated temperature in order to change conformation. Complement; C9; Membrane assembly; Cytotoxicity
The 23 kDa polypeptide of the photosynthetic oxygen‐evolving complex from mustard seedlings (Sinapis alba L.) Nucleotide sequence of cDNA and evidence for phytochrome control of its mRNA abundance
Authors: Wenng A. , Ehmann B. , Schäfer E.
Published: July 2002

The nucleotide sequence of a cDNA from mustard shows 78% homology in deduced amino acid sequence for the mature protein compared to the sequence for the 23 kDa protein of the oxygen‐evolving complex from spinach [(1987) FEBS Lett. 216, 234–240]. There is also a high degree of homology between the premature protein sequences concerning the hydrophobic domain and its distance from the suggested processing site. The accumulation of mRNA for the 23 kDa protein in mustard was stimulated by continuous far‐red light and reversal experiments by means of red/far‐red light pulse treatment show the involvement of phytochrome in controlling the mRNA abundance for the 23 kDa polypeptide in mustard. The accumulation of the mRNA can be inhibited in white light if the seedlings are treated with the herbicide Norflurazon.
Resonance Raman characterization of hog thyroid peroxidase an SERRS study
Authors: Hashimoto S. , Nakajima R. , Yamazaki I. , Kotani T. , Ohtaki S. , Kitagawa T.
Published: July 2002

Resonance Raman (RR) spectra of hog thyroid peroxidase (TPO) were observed for the first time and compared with those of lactoperoxidase (LPO) and horseradish peroxidase (HRP). Since TPO purified by monoclonal antibody‐assisted immunoaffinity chromatography was strongly fluorescent, the surface enhancement technique using Ag colloid adsorption was used for the oxidized form, but ordinary RR spectra could be obtained for the reduced form. The RR spectra of TPO were distinct from those of HRP in both the oxidized and reduced states and indicated the presence of six‐coordinated iron‐protoporphyrin.
The influence of nerve growth factor on the activities of adenylate cyclase and high‐affinity GTPase in pheochromocytoma PC12 cells
Authors: Golubeva E.E. , Posypanova G.A. , Kondratyev A.D. , Melnik E.I. , Severin E.S.
Published: July 2002

The influence of nerve growth factor (NGF) on the activities of adenylate cyclase and high‐affinity GTPase in pheochromocytoma PC12 cells was studied. Incubation of cells with nerve growth factor led to a rapid activation of adenylate cyclase accompanied by an inhibition of high‐affinity GTPase. By the 10th min of incubation the activity of adenylate cyclase had been reduced 2‐fold when compared to the control. The activity of GTPase, however, increased. No significant changes in the cAMP level were detected. The data obtained indicate that NGF interaction with PC12 cells induces changes in the adenylate cyclase system and this process involves G‐proteins that regulate the adenylate cyclase activity.
Importance of the α3‐fragment of complement C4 for the binding with C4b‐binding protein
Authors: Hessing Martin , van't Veer Cornells , Hackeng Tilman M. , Bouma Bonno N. , Iwanaga Sadaaki
Published: July 2002

The human regulatory complement component C4b‐binding protein (C4BP) is a multimene plasma protein, which regulates the classical pathway of the complement system. C4BP functions as a cofactor to factor 1 in the degradation of C4b and accelerates the decay rate of the C4b2a complex. Previously, we have demonstrated that monoclonal antibodies (C4‐2 and 9) directed against the α'‐chain of C4b inhibit the binding of C4b to C4BP. In order to identify the structural domain of C4b that binds C4BP, proteolytic fragments of C4 were generated with trypsin and Staphylococcus aureus V8 protease. Sodium dodecyl sulfate polyacrylamide gel electrophoresis, immunoblotting and amino acid sequence analysis of the proteolytic fragments reactive with the anti‐C4 mAb's revealed that the residues Ala738‐Arg826 of the α3‐fragment of C4b are important for the interaction with C4BP.
Electron microscopy study of human myeloma immunoglobulin G1
Authors: Ryazantsev S.N. , Abramov V.M. , Zav'yalov V.P. , Vasiliev V.D.
Published: July 2002

Human immunoglobulin G1 Van was studied by negative staining, freeze drying and high resolution shadow casting. The Fab and Fe subunits of an intact IgG1 molecule were shown to possess limited mobility. It was found that about 70°C of molecules in the IgG1 Van specimen are not flat but have a tripod‐like shape.
Characterization of cDNA clones encoding guinea pig neutrophil cationic peptides
Authors: Nagaoka Isao , Someya Akimasa , Iwabuchi Kazuhisa , Yamashita Tutsuhisa
Published: July 2002

cDNA clones encoding antimicrobial guinea pig neutrophil cationic peptides GNCP‐1 and GNCP‐2 were isolated from a bone marrow cell cDNA library. Analysis of these clones indicated that both GNCPs were produced as precursor proteins comprising 93 amino acid residues, which were composed of signal sequences (N‐terminal 19 residues), pro‐peptide sequences (43 residues) and mature GNCP sequences (31 residues). The deduced amino acid sequence showed that there were only two amino acid differences between GNCP‐1 and GNCP‐2, one in the pro‐peptide region and one in the mature peptide region. Interestingly, Northern blot analysis and transcription run‐off assay revealed that the expression of GNCP mRNA and the transcription of GNCP gene was observed in bone marrow cells but not in mature neutrophils. These observations suggest that mature neutropils, despite their abundant content of GNCPs, lose the capacity to synthesize GNCPs.
Vector methylation inhibits transcription from the SV40 early promoter
Authors: Bryans M. , Kass S. , Scivwright C. , Adams R.L.P.
Published: July 2002

Methylation of a plasmid containing the sv4O promoter linked to the chloramphenicol acetyl transferase (CAT) gene, with either murine DNA methylase or methylase 5ssl results in inhibition of the expression or the reporter gene after transfection into cultured cells. Methylation of the plasmid with the methylases HhaI and HpaII has no effect on the expression of this gene. Protein‐DNA interactions in the SV40 promoter are not affected by the presence of methylcytosine suggesting that inactivation results from the formation of an inactive chromatin structure that is dependent on the high CG content of the plasmid.
Ionization of the heme propionate substituents in pseudomonad cytochromes c‐551
Authors: Cai Mengli , Timkovich Russell
Published: July 2002

The heme propionate substituents in Pseudomonas cytochrome c‐551 are partially buried by folds of polypeptide in the structure of the protein, and are involved in several hydrogen bonds. The ionization behavior of these groups has been of interest because the oxidation potential of the heme changes with pH in a manner that may parallel ionization of a propionate. The ionization pK
a's of these groups have been determined by following the NMR chemical shifts of nearby protons acting as probes of the ionization state of the propionates. In Pseudomonas aeruginosa c‐551 the 13‐propionate (IUB‐IUPAC porphyrin nomenclature) has been assigned a pK
a of 3.1, and the 17‐propionate a pK
a of 7.2. In the homologous Pseudomonas stutzeri c‐551, the respective propionates both have pK
a values of 3.0.
Mutations in β‐actin: influence on polymer formation and on interactions with myosin and profilin
Authors: Aspenström Pontus , Schutt Clarence E. , Lindberg Uno , Karlsson Roger
Published: July 2002

Two β‐actin mutants, one with proline 38 replaced with alanine (P38A) and the other with cysteine‐374 replaced with serine (C374S), as well as the wild‐type β‐actin, were expressed in the yeast, S. cerevisiae, purified to homogeneity, and analyzed in vitro for polymerizability and interaction with DNase I, myosin, and profilin. Both mutations interfered with the polymerization of the actin, and with its interaction with myosin. The C374S mutation had the most pronounced effect; it reduced the polymerizability of the actin, abolished its binding to profilin, and filaments containing this mutation moved at reduced rates in the in vitro ‘motility assay’. The ATPase activity measured in solutions containing myosin subfragment 1 was similar for both the mutant and wild‐type actins.
Neuron‐specific glucose transporter (NSGT): CNS distribution of GLUT3 rat glucose transporter (RGT3) in rat central neurons
Authors: Nagamatsu Shinya , Sawa Hiroki , Kamada Kouichi , Nakamichi Yoko , Yoshimoto Katsuhiko , Hoshino Takao
Published: July 2002

The identity of the glucose transporters (GLUT) expressed in neurons in situ has yet to be fully established. In the present study we have isolated the GLUT3 (RGT3) cDNA and produced anti RGT3 polyclonal antibody allowing us to investigate the cellular localization and tissue distributions of RGT3 mRNA and protein in the central nervous system of the rat by the methods of in situ hybridization and immunohistochemistry. Here we demonstrate the direct evidence that RGT3 is present in neurons in adult rat brain. In situ hybridization showed the expression of RGT3 mRNA mostly in the regions of hippocampus, cerebral cortex, striatum, and the granule cell layer of the cerebellum, indicating that RGT3 mRNA is predominantly expressed within neurons. Immunohistochemistry showed that RGT3 protein is widely distributed in the rat brain, and concentrated on the plasma membrane of neurons. Double labeling studies with anti‐RGT3, glial fibrillary acidic protein (GFAP), and neuron specific enolase (NSE) antibodies revealed the specific expression of RGT3 protein in neurons. Thus, RGT3 is indicated to be a neuron specific glucose transporter isoform (NSGT), and suggested to play a functionally significant role in rat central neurons.