bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Influence of Thyroid State on Hepatic Glycolysis
Authors: Gregory Roland B. , Berry Michael N. 
Published: March 2005

The effects of thyroid status on glycolysis using 10, 20, and 40 mM glucose have been examined in hepatocytes derived from hypothyroid, euthyroid, and hyperthyroid rats. For any given concentration of added glucose, total glycolytic rates, as measured by the release of tritium from [6‐3H]glucose, were similar in all thyroid states. The aerobic component of glycolysis, where cytoplasmically generated reducing equivalents are transferred to the mitochondria for oxidation, was the major component in the hyper‐thyroid state, at all concentrations of glucose. In contrast, the aerobic proportion of glycolysis in the hypothyroid and euthyroid states decreased with increasing concentration of added glucose and the anaerobic component became dominant above 20 mM glucose. Cytoplasmic reducing equivalents generated during aerobic glycolysis were transferred to the mitochondria via both the glycerol 1‐phosphate and malate/aspartate shuttles in each thyroid state, even though the former shuttle was considerably depressed in the livers of hypothyroid rats. Both asparagine and aminooxyacetate had only minor effects on the rate of glycolysis, but aminooxyacetate depressed the contribution of aerobic glycolysis whereas asparagine had relatively little influence. The respiration rate in the presence of 40 mM glucose was twice as high in hepatocytes from hyperthyroid rats as in cells from hypothyroid animals, and 1.4 times as high as in hepatocytes from euthyroid rats. Smaller stimulations were observed with lower concentrations of added glucose. Furthermore, the increase in respiratory rate over the endogenous value, induced by 10 mM glucose, was six times higher in cells from hyperthyroid rats than in hepatocytes from hypothyroid animals and 2.7 times higher than that observed with cells from euthyroid rats.The insensitivity of glycolysis to thyroid status in contrast to the marked response of respiration provides additional support for the view that the stimulation of metabolism by thyroid hormone is mediated primarily by its action on mitochondrial processes.
Isolation and Structural Characterization of Trimeric Cyanobacterial Photosystem I Complex with the Help of Recombinant Antibody Fragments
Authors: Tsiotis Georgios , Haase Winfried , Engel Andreas , Michel Hartmut 
Published: March 2005

A monoclonal antibody was derived from mice immunized with the native trimeric, photosystem I (PSI) complex from the cyanobacterium Synechococcus PCC 7002 which reacts with a conformational epitope of the PSI complex. As seen by immunoelectron microscopy, the mAb bound to the stromal side of the thylakoid membranes. The DNA sequence encoding variable regions of the mAb was cloned into recombinant plasmids, sequenced and expressed in Escherichia coli. ELISA, Western blots and immunoelectron microscopy provided evidence that the expressed paired variable domain (Fv) fragments bind to the antigen in the same way as the parent mAb.A one‐step purification was applied to purify the trimeric PSI complex using an affinity tag attached to the Fv fragment. Analysis by gel electrophoresis and N‐terminal sequencing revealed the presence of the psaA, psaB, psaC, psaD, psaE, psaF and psaL gene products. The antenna size of the isolated PSI/Fv was 139±9 chlorophyll a/primary electron donor. Flash‐induced absorption‐change measurements showed that the complex exhibited electron transfer from the primary electron donor, P700, to the Fe‐S center, FA/FB. The position of the bound Fv fragment on the trimeric PSI surface was determined by high‐resolution electron microscopy and digital image processing.
Structure of the Capsular Polysaccharide of Vibrio cholerae O139 Synonym Bengal Containing D‐galactose 4,6‐Cyclophosphate
Authors: Knirel Yuriy A. , Paredes Liliana , Jansson Per‐Erik , Weintraub Andrej , Widmalm Göran , Albert M. John 
Published: March 2005

The capsular polysaccharide (CPS) of Vibrio cholerae O139 synonym Bengal, which is thought to carry determinants of O‐specificity, was isolated by phenol/water extraction followed by delipidation of the contaminating lipopolysaccharide at pH 4.2 and gel‐permeation chromatography. The CPS contained d‐galactose, 3,6‐dideoxy‐l‐xylo‐hexose (colitose, Col), 2‐acetamido‐2‐deoxy‐d‐glucose, 2‐acetamido‐2,6‐dideoxy‐d‐glucose (N‐acetyl‐d‐quinovosamine, d‐QuiNAc),d‐galacturonic acid (d‐GalA), and phosphate. The CPS was studied by NMR spectroscopy, methylation analysis, and selective degradations, including partial acid hydrolysis at pH 3.1 and dephosphorylation with aqueous 48% hydrofluoric acid, which both resulted in complete cleavage of Col. It was concluded that the CPS is built up of hexasaccharide repeating units containing inter aliad‐galactose 4,6‐cyclophosphate and having the following structure
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These data basically confirm the structure of the V. cholerae CPS proposed on the basis of an NMR study [L. M. Preston et al. (1995) J. Bacteriol. 177, 835–838] and specify exactly the absolute configurations of the constituent monosaccharides and the position of the cyclic phosphate.
Structures of the O‐specific Polysaccharide Chains of Pectinatus cerevisiiphilus and Pectinatus frisingensis Lipopolysaccharides
Authors: Senchenkova Sof'ya N. , Shashkov Alexander S. , Moran Antony P. , Helander Ilkka M. , Knirel Yuriy A. 
Published: March 2005

Mild acid hydrolysis of the smooth‐type lipopolysaccharide (LPS) of Pectinatus frisingensis afforded no polysaccharide but monomeric 6‐deoxy‐l‐altrose (l‐6dAlt) which was identified by anion‐exchange chromatography in borate buffer, GLC/MS, 1H‐NMR spectroscopy, and optical rotation. LPS was degraded with alkali under reductive conditions to give a completely O‐deacylated polysaccharide, which was studied by methylation analysis, 1H‐NMR and 13C‐NMR spectroscopy, including sequential, selective spin‐decoupling, two‐dimensional correlation spectroscopy (COSY), COSY with relayed coherence transfer, two‐dimensional heteronuclear 13C,1H‐COSY., one‐dimensional NOE and two‐dimensional rotating‐frame NOE spectroscopy. It was found that the O‐specific polysaccharide chain of P. frisingensis LPS is a homopolymer of 6‐deoxy‐l‐altrofuranose built up of tetrasaccharide‐repeating units having the following structure:
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Similarly, mild acid degradation of smooth‐type LPS of Pectinatus cerevisiiphilus resulted in depolymerisation of the polysaccharide chain to give a disaccharide consisting of d‐glucose and d‐fucose. Study of the disaccharide by methylation analysis and alkali‐degraded LPS by one‐dimensional and two‐dimensional 1H‐NMR and 13C‐NMR spectroscopy showed that the O‐specific polysaccharide of P. cerevisiiphilus has the following structure:
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Molecular Structure and Mechanism of Action of the Crotoxin Inhibitor from Crotalus durissus terrificus Serum
Authors: Perales Jonas , Villela Christina , Domont Gilberto B. , Choumet Valérie , Saliou Bernard , Moussatché Haity , Bon Cassian , Faure Grazyna 
Published: March 2005

An antivenom protein has been identified in the blood of the snake Crotalus durissus terrificus and proved to act by specifically neutralizing crotoxin, the main lethal component of rattlesnake venoms. The aim of this study was to purify the crotoxin inhibitor from Crotalus serum (CICS), and to analyze its mechanism of action.CICS has been purified from blood serum of the Crotalus snake by gel filtration on Sephadex G‐200, ion‐exchange chromatography on DEAE‐Sephacel, and FPLC gel filtration on a Superose 12 column. It is an oligomeric glycoprotein of 130 kDa, made by the non‐covalent association of 23–25‐kDa subunits. Two different subunit peptides were identified by SDS/PAGE, however, their N‐terminal sequences are identical. They are characterized by the absence of methionine residues and a high content of acidic, hydrophobic and cysteine residues.The neutralizing effect of purified CICS towards the neurotoxic effects of crotoxin has been demonstrated in vivo by lethality assays. CICS binds to the phospholipase subunit CB of crotoxin, but not to the acidic chaperon subunit CA; it efficiently inhibits the phospholipase activity of crotoxin and its isolated CB subunit and evokes the dissociation of the crotoxin complex.The molecular mechanism of the interaction between CICS and crotoxin seems to be very similar to that of crotoxin with its acceptor. It is, therefore, tempting to suggest that CICS acts physiologically as a false crotoxin acceptor that would retain the toxin in the vascular system, thus preventing its action on the neuromuscular system.
Identification and Partial Purification of (Ca2+ or Mg2+)‐ATPase in Renal Brush‐Border Membranes
Authors: Van Erum Monique , Lemmens Raf , Berden Jan , Teuchy Henri , Vanduffel Luc 
Published: March 2005

The protein responsible for the (Ca2+ or Mg2+)‐ATPase activity in brush‐border membranes from pig kidney tubular cells was characterized to distinguish this enzyme from the N‐ethylmaleimide‐sensitive Mg2+‐ATPase, also present in renal brush borders. Both enzymes are clearly different in their pH optimum and their sensitivity to divalent cations, nucleoside 5′‐triphosphates and inhibitors.Solubilization of the (Ca2+ or Mg2+)‐ATPase from brush‐border membrane vesicles was accomplished with Nonidet P‐40 or dodecylmaltoside. However, simultaneous inactivation of the enzyme was inevitable.A tenfold enrichment of the ATPase activity was obtained by chromatofocusing of Nonidet‐P‐40‐solubilized brush borders. A similar degree of purification was achieved by ion‐exchange chromatography of dodecylmaltoside‐solubilized preparations. From the SDS/polyacrylamide gels of partially purified (Ca2+ or Mg2+)‐ATPase, a few protein bands could still be tentatively identified as responsible for the enzyme activity.Labeling of solubilized brush‐border preparations with several radioactive ATP analogues also revealed that a protein band of molecular mass 90 kDa is the most probable candidate for the catalytic peptide of the (Ca2+ or Mg2+)‐ATPase.Finally, immunoprecipitation as well as semi‐dry blotting with antibodies generated against partially purified enzyme preparations, confirmed that a 90‐kDa component is a reasonable candidate for the (Ca2+ or Mg2+)‐ATPase in renal brush‐border membranes.
Inhibition of 3‐Hydroxy‐3‐Methylglutaryl‐CoA Reductase and Citrate Synthase by Sulfoxides and Sulfones of Substrate‐analogue CoA‐thioether Derivatives
Authors: Karl Rosa Maria , Hupperich Martin , Thomer Anna , Eggerer Hermann 
Published: March 2005

Sulfoxides and sulfones were prepared by specific oxidation of 3‐hydroxy‐3‐methylglutaryl‐CoA‐analogue CoA‐thioether derivatives and their kinetic properties were determined with 3‐hydroxy‐3‐methylglutaryl‐CoA reductase. The oxidized CoA‐thioether derivatives with a hydroxyl group at C3 were powerful competitive inhibitors, their Ki values being much smaller than the Km for 3‐hydroxy‐3‐methyl‐glutaryl‐CoA.Sulfoxides and sulfones of substrate analogues of citrate synthase were also prepared. When tested in the appropriate reaction with citrate synthase, the sulfoxide and sulfone derivatives were competitive inhibitors, but their Ki values were greater than the Km values of the corresponding unmodified substrates.
Integral Cytochrome‐c Oxidase
Authors: Soulimane Tewfik , Buse Gerhard 
Published: March 2005

A new rapid procedure for the preparation of monodispersed highly active cytochrome‐c oxidase from bovine heart is described. The crucial step is the separation of cytochrome‐c oxidase from cytochrome‐c reductase by selective solubilization in the non‐ionic detergents Triton X‐100 or lauryl β‐d‐maltoside. The enzyme is purified by subsequent anion‐exchange chromatography. The preparation is finished within two days yielding approximately 60% of the oxidase present in mitochondria. The enzyme has a heme a/protein ratio of 9.7 × 0.5 nmol/mg, approximately equal to the theoretical value of 9.77 nmol/mg based on a molecular mass of 204.696 kDa for the protein monomer. SDS/PAGE of the preparation reveals the presence of the well‐known thirteen protein components. Quantitative Edman degradation of the enzyme exclusively releases the known ten N‐terminal residues; three of the thirteen protein components are blocked at the N‐terminus. The preparation is highly active with maximal turnover numbers of approximately 600 s−1, identical to the maximal activity found in the mitochondrial membrane under these conditions. No g= 12 signal and no adventitious copper signal are observed in the EPR spectrum. The enzyme exhibits a fast monophasic reaction with cyanide.Determination of the metal contents of the enzyme indicates the stoichiometric presence of three copper ions besides two iron, one magnesium and one zinc ion in relation to the 94 sulfur atoms of the protein monomer. Gel‐filtration experiments show a monodispersed dimeric association to form a complex of approximately 500 kDa. The phosphorus content, 44 ± 6.8 atoms/dimer, results from 59% cardiolipin, 23% phosphatidylethanolamine and 18% phosphatidylcholine, indicating a stable lipid shell, different from other previously described preparations.Crystals have been obtained from these preparations and are investigated for their suitability for X‐ray work.
Inhibition of Bovine Cytochrome P‐45011β by 18‐Unsaturated Progesterone Derivatives
Authors: Delorme Cécile , Piffeteau Annie , Viger Antoinette , Marquet Andrée 
Published: March 2005

The last step of aldosterone biosynthesis, an 11β‐hydroxylation followed by two 18‐hydroxylations, are catalyzed, in the bovine system, by the same enzyme, the cytochrome P‐45011β (deoxycorticosterone (DOC) → corticosterone → 18‐hydroxycorticosterone → aldosterone). The 11β‐ and 18‐hydroxylase activities were studied separately with a reconstituted enzymic system, using 11‐deoxy[14C]corticosterone and [3H]corticosterone, respectively, as substrates.The inhibition of 11β‐hydroxylase activity by corticosterone was competitive (Ki= 60 μM) showing that transformation of both substrates occurs at the same site. Double‐label/double‐substrate experiments, using an equimolar mixture of 11‐deoxy[14C]corticosterone and [3H]corticosterone, suggested that 18‐hydroxycorticosterone is directly formed from 11‐deoxycorticosterone without the intermediate corticosterone leaving the enzyme.Inhibitions by 18‐vinylprogesterone and 18‐ethynylprogesterone, potent inhibitors of aldosterone biosynthesis [Viger, A., Coustal, S., Pérard, S., Piffeteau, A. & Marquet, A. (1989) J. Steroid Biochem. 33, 119–124], were characterized for both activities (11β‐ and 18‐hydroxylase). The value of reversible Ki for the 18‐hydroxylation (Ki= 5 μM for 18‐vinylprogesterone and 30 μM for 18‐ethynylprogesterone) is lower than that for the 11β‐hydroxylation (30 μM and 100–150 μM, respectively); the former inhibitor is stronger than the latter for both steps.The binding of substrates and inhibitors to the active site was also examined by difference absorption spectroscopy. 18‐Vinylprogesterone gave rise to a type I spectrum with a Ks value of 35 μM close to that of progesterone, while 18‐ethynylprogesterone showed a reverse type I spectrum with a much higher Ks value (140 μM). Based on these results, a hypothetical model, involving a conformational change of the enzyme for the second step, is proposed.
Occurrence of Isospora suis in Germany, Switzerland and Austria
Authors: Mundt H.‐C. , Cohnen A. , Daugschies A. , Joachim A. , Prosl H. , Schmäschke R. , Westphal B. 
Published: March 2005

SummaryNationwide surveys for the occurrence of Isospora suis were carried out in Germany, Austria and Switzerland including a questionnaire regarding herd size, health status and management practices and a coccidiosis sampling kit for pooled faecal samples from litters of suckling piglets. A total of 184 veterinary practices participated in the survey and returned 1745 samples (331 kits) from 324 farms in the north (n = 98), south (n = 84), centre/east (n = 42) and west (n = 10) of Germany, Austria (n = 61) and Switzerland (n = 29) with larger farms in north and centre/east (average number of sows: 270 and 500) and smaller ones in the south (95), Austria (60) and Switzerland (43). Larger farms tended to have better hygienic standards (slatted floors, disinfection of the farrowing units). The majority of the participating farms (93.5%) reported problems with diarrhoea in piglets at 2–3 weeks of age, significantly associated (P < 0.001) with uneven weaning weights (94.9%). Toltrazuril (5%; Baycox®) was used only rarely; however, in these farms unevenness of weaning weights was less frequently observed (P = 0.011). A 76.2% of the farms were positive for I. suis (samples contained mostly low or moderate oocyst numbers), especially in the south (P < 0.001). Oocysts were more frequently found in samples from farms with reported diarrhoea (P = 0.011), uneven weight gain (P = 0.019) or in herds of small size (P < 0.001). Disinfection, floor type or treatment with toltrazuril did not affect the frequency of observation of oocysts.
Development of hydrogel patch for controlled release of alpha‐hydroxy acid contained in tamarind fruit pulp extract
Authors: Viyoch J. , Sudedmark T. , Srema W. , Suwongkrua W. 
Published: March 2005

SynopsisThe aim of this study was to develop hydrogel patch using crosslinked chitosan–starch as polymeric matrix for controlling the release of the natural alpha‐hydroxy acid (AHA) contained in the extract of tamarind's fruit pulp. The chitosan (MW 100 000) was blended with corn, tapioca or rice starch in various ratios and then crosslinked with glutaraldehyde. The physical characteristics, mechanical resistance, bio‐adhesion property and surface morphology of the prepared hydrogel patches with and without the extract were investigated. The release patterns of the hydrogel patches containing the extract were investigated by measuring the amount of tartaric acid, a major AHA present in the tamarind's fruit pulp extract, accumulated in the receptor medium of the vertical diffusion cell at various time intervals over a period of 6 h. The results indicated that the formulations of chitosan : corn starch 4.5 : 0.5 with glutaraldehyde 0.02% w/w (C4.5C0.5G0.02) or 0.04% w/w (C4.5C0.5G0.04), chitosan : tapioca starch 4.5 : 0.5 with glutaraldehyde 0.04% w/w (C4.5T0.5G0.04) or 0.05% w/w (C4.5T0.5G0.05), and chitosan : rice starch 4.5 : 0.5 with glutaraldehyde 0.04% w/w (C4.5R0.5G0.04) and chitosan : rice starch 4.0 : 1.0 with glutaraldehyde 0.03% w/w (C4.0R1.0G0.03) provided the flexible and elastic patches with good bio‐adhesive property. The tensile strength values ranged from 5 to15 N mm−2 and the elasticity ranged from 30 to 60%. The addition of the extract in these formulations significantly increased the tensile strength values of the obtained patches. The patch of C4.0R1.0G0.03 formulation containing the extract showed relatively highest porosity, corresponding to its highest amount (12.02 ± 0.33 mg) and rate (0.452 ± 0.012 mg mm−2 min−1/2) of tartaric acid released. The amounts of tartaric acid released from the developed hydrogel patches were proportional to a square root of time (Higuchi's model), particularly the release from C4.0R1.0G0.03 (R2, 0.9978 ± 0.0020) and C4.5R0.5G0.04 (R2, 0.9961 ± 0.0024) patches.
Pityriasis versicolor alba
Authors: Thoma W , Krämer H‐J , Mayser P 
Published: March 2005

ABSTRACTPityriasis versicolor alba is a hypopigmented or depigmented variant of pityriasis versicolor characterized by maculous, partly pityriasiform, scaly depigmented lesions occurring particularly in seborrhoeic areas. Long‐persisting hypopigmentation after healing of the pityriasis versicolor was first described by Gudden in 1853. Hypopigmentation and depigmentation were later differentiated as an independent variant of the disease. In 1848, Eichstedt recognized the pathogen‐related character of pityriasis versicolor in its hyperpigmented form. Today it is generally accepted that the disease is caused by yeasts of the genus Malassezia, of which nine species are differentiated. It is controversial whether a single species is responsible for the disease. The pathogenesis of depigmentation has not been established. A screening effect by the scale layer as well as toxic effects on pigment synthesis by fungal metabolites have been discussed. With regard to the second mechanism, the newly discovered tryptophan‐derived metabolites of M. furfur might be significant. Evidence‐based data concerning the therapy of pityriasis versicolor alba do not exist. According to current recommendations, pityriasis versicolor should be rapidly treated with antimycotics, followed by ultraviolet therapy to induce maturation of existent melanosomes and accelerate repigmentation. However, depigmented lesions are difficult to improve by ultraviolet therapy.
Management of erosive lichen planus with topical tacrolimus and recurrence secondary to metoprolol
Authors: Meyer S , Burgdorff T , Szeimies RM , Vogt T , Landthaler M , Karrer S 
Published: March 2005

ABSTRACTMetoprolol, a widely prescribed β‐adrenergic receptor blocker, has occasionally been associated with a diversity of cutaneous reactions. We present a 79‐year‐old male patient with erosive lichen planus (LP) on the feet and hands who was successfully treated with topical tacrolimus. Six months after the lesions had been cured the patient received the β‐receptor blocker metoprolol for the treatment of hypertonus. Within only 2 weeks of metoprolol intake the erosive lesions on the palms and feet recurred. After discontinuation of the drug and repetitive topical treatment with tacrolimus a complete remission of the lesions could be achieved. The recurrence of erosive LP probably secondary to metoprolol and the therapeutic success of topical tacrolimus in the treatment of LP are discussed.
Livedo reticularis associated with interferon α therapy in two melanoma patients
Authors: Ruiz‐Genao DP , García‐F‐Villalta MJ , Hernández‐Núñez A , Ríos‐Buceta L , Fernández‐Herrera J , García‐Díez A 
Published: March 2005

ABSTRACTWe report two patients who developed intense livedo reticularis clearly related to the administration of interferon α 2b as an adjuvant therapy for melanoma. Histological studies showed scattered perivascular infiltrates without vasculitis. Laboratory tests excluded any underlying condition. Resolution of the symptoms was observed in both patients when interferon α was withdrawn. These cases highlight the occurrence of livedo reticularis as an uncommon side‐effect of interferon α treatment.