bluuebunny/crossref_metadata_2025 huggingface dataset:
Chlorophyll b is involved in long‐wavelength spectral properties of light‐harvesting complexes LHC I and LHC II
Authors: Schmid Volkmar H.R. , Thomé Peter , Rühle Wolfgang , Paulsen Harald , Kühlbrandt Werner , Rogl Hans
Published: July 2002

Chlorophyll (Chl) molecules attached to plant light‐harvesting complexes (LHC) differ in their spectral behavior. While most Chl a and Chl b molecules give rise to absorption bands between 645 nm and 670 nm, some special Chls absorb at wavelengths longer than 700 nm. Among the Chl a/b‐antennae of higher plants these are found exclusively in LHC I. In order to assign this special spectral property to one chlorophyll species we reconstituted LHC of both photosystem I (Lhca4) and photosystem II (Lhcb1) with carotenoids and only Chl a or Chl b and analyzed the effect on pigment binding, absorption and fluorescence properties. In both LHCs the Chl‐binding sites of the omitted Chl species were occupied by the other species resulting in a constant total number of Chls in these complexes. 77‐K spectroscopic measurements demonstrated that omission of Chl b in refolded Lhca4 resulted in a loss of long‐wavelength absorption and 730‐nm fluorescence emission. In Lhcb1 with only Chl b long‐wavelength emission was preserved. These results clearly demonstrate the involvement of Chl b in establishing long‐wavelength properties.
Increased expression of mitochondrial transcription factor A and nuclear respiratory factor‐1 in skeletal muscle from aged human subjects
Authors: Lezza Angela M.S. , Pesce Vito , Cormio Antonella , Fracasso Flavio , Vecchiet Jacopo , Felzani Giorgio , Cantatore Palmiro , Gadaleta Maria Nicola
Published: July 2002

The expression of two factors involved in the nuclear–mitochondrial crosstalk, namely the mitochondrial transcription factor A (TFAM) and the nuclear respiratory factor‐1 (NRF‐1), was studied in human skeletal muscle biopsies of young and aged subjects. Aged subjects presented a 2.6‐fold and an 11‐fold increase of the levels of TFAM protein and TFAM mRNA, respectively. The increased expression of TFAM was associated to the doubling of NRF‐1 DNA‐binding affinity and to a 6‐fold increase of NRF‐1 mRNA level. The upregulation of TFAM and NRF‐1, in aged skeletal muscle, appears involved in the pathway leading to the age‐related increase of mitochondrial DNA content.
Optimization of the antimicrobial activity of magainin peptides by modification of charge
Authors: Dathe Margitta , Nikolenko Heike , Meyer Jana , Beyermann Michael , Bienert Michael
Published: July 2002

Investigation of magainin II amide analogs with cationic charges ranging between +3 and +7 showed that enhancement of the peptide charge up to a threshold value of +5 and conservation of appropriate hydrophobic properties optimized the antimicrobial activity and selectivity. High selectivity was the result of both enhanced antimicrobial and reduced hemolytic activity. Charge increase beyond +5 with retention of other structural motifs led to a dramatic increase of hemolytic activity and loss of antimicrobial selectivity. Selectivity could be restored by reduction of the hydrophobicity of the hydrophobic helix surface (H
hd), a structural parameter not previously considered to modulate activity. Dye release experiments with lipid vesicles revealed that the potential of peptide charge to modulate membrane activity is limited: on highly negatively charged 1‐palmitoyl‐2‐oleoylphosphatidyl‐DL‐glycerol bilayers, reinforcement of electrostatic interactions had an activity‐reducing effect. On neutral 1‐palmitoyl‐2‐oleoylphosphatidylcholine bilayers, the high activity was determined by H
hd. H
hd values above a certain threshold led to effective permeabilization of all lipid systems and even compensated for the activity‐reducing effect of charge increase on highly negatively charged membranes.
Expression and biochemical analyses of the recombinant potato virus X 25K movement protein
Authors: Kalinina N.O. , Fedorkin O.N. , Samuilova O.V. , Maiss E. , Korpela T. , Morozov S.Yu. , Atabekov J.G.
Published: July 2002

The 25K movement protein (MP) of potato virus X (PVX) is encoded by the 5′‐proximal gene of three overlapping MP genes forming a ‘triple gene block’. The PVX 25K MP (putative NTPase‐helicase) has been synthesized in Escherichia coli as a recombinant containing a six‐histidine tag at the amino terminus. The His‐tagged 25K protein was purified in a one‐column Ni‐chelate affinity chromatography procedure. In the absence of any other viral factors, this protein had obvious Mg2+‐dependent ATPase activity, which was stimulated slightly (1.7–1.9‐fold) by various polynucleotides. Like other viral proteins possessing ATPase‐helicase motifs and many plant viral movement proteins, the PVX 25K MP was able to bind nucleic acids in vitro. The RNA binding activity of the 25K MP was pronounced only at very low salt concentrations and was independent of its ATPase activity.
Acetylation of ribosomal protein S5 affected by defects in the central pseudoknot in 16S ribosomal RNA?
Authors: Poot Raymond A , Jeeninga Rienk E , Pleij Cornelis W.A , van Duin Jan
Published: July 2002

We have analyzed the ribosomal protein profile of Escherichia coli 30S subunits with the mutation C18A in the central pseudoknot of their 16S ribosomal RNA. This mutation was shown to inhibit translational activity in vivo and to affect ribosome stability in vitro. The majority of the mutant 30S particles were present as free subunits in which a reproducible decrease in amount of proteins S1, S2, S18 and S21 was observed. The protein gels also showed the appearance of a satellite band next to S5. This band reacted with anti‐S5 antibodies and had a slightly increased positive charge. The simplest interpretation of these findings, also considering published data, is that the satellite band is S5 with a non‐acetylated N‐terminal alanine. Underacetylation of S5 due to mutations in the 16S rRNA implies that the modification is performed on the ribosome.
The cloning and characterization of human MyD88: a member of an IL‐1 receptor related family1
Authors: Bonnert Timothy P , Garka Kirsten E , Parnet Patricia , Sonoda Gonosuke , Testa Joseph R , Sims John E
Published: July 2002

Murine MyD88, an RNA with homology both to the interleukin‐1 receptor signaling domain and to ‘death‐domains’, is rapidly upregulated during differentiation of the myeloleukemic cell line M1. We have cloned the human homologue of murine MyD88 and re‐evaluated the murine sequence. The open reading frame for both species encodes a 296 amino acid protein, which for murine MyD88 is 53 amino acids longer than originally published. Human MyD88 cDNA is encoded by 5 exons, and maps to chromosome 3p21.3‐p22 by fluorescence in situ hybridization (FISH). Overexpression of the death domain region leads to transcriptional activation of the IL‐8 promoter.
Murine epidermal lipoxygenase (Aloxe) encodes a 12‐lipoxygenase isoform1
Authors: Kinzig Andreas , Fürstenberger Gerhard , Bürger Friederike , Vogel Sonja , Müller-Decker Karin , Mincheva Antoaneta , Lichter Peter , Marks Friedrich , Krieg Peter
Published: July 2002

Using a combination of conventional screening procedures and polymerase chain reaction cloning, we have isolated a cDNA encoding an epidermis‐type 12‐lipoxygenase (e12‐lipoxygenase) from mouse epidermis. The open reading frame corresponds to a protein of 662 amino acids and was found to be 99.8% identical to the ORF of an epidermal lipoxygenase gene Aloxe, described recently [Van Dijk et al. (1995) Biochim. Biophys. Acta 1259, 4–8]. When expressed in human embryonic kidney cells the recombinant protein could be shown to synthesize 12(S)‐HETE from arachidonic acid. By fluorescence in situ hybridization the e12‐lipoxygenase gene was localized to chromosome band 11 B1–B3.
Diverse molecular interactions of the hnRNP K protein
Authors: Bomsztyk Karol , Van Seuningen Isabelle , Suzuki Hideaki , Denisenko Oleg , Ostrowski Jerzy
Published: July 2002

© 1997 Federation of European Biochemical Societies.
ICRF‐193, a catalytic inhibitor of DNA topoisomerase II, delays the cell cycle progression from metaphase, but not from anaphase to the G1 phase in mammalian cells
Authors: Iwai Miwako , Hara Akira , Andoh Toshiwo , Ishida Ryoji
Published: July 2002

We have shown previously that ICRF‐193, a catalytic inhibitor of DNA topoisomerase II (topo II), delays cell cycle progression in HeLa S3 cells. We report here that the delay of the transition in M phase is observed when HeLa S3 cells were treated with ICRF‐193 during metaphase, but not thereafter. ICRF‐193 also delayed the degradation of cyclin B in the transition from M to G1 phase, while in Chinese hamster ovary (CHO) cells the drug did not delay the progression in M phase. Since HeLa S3 and CHO cells are ‘stringent’ and ‘relaxed’ in mitotic control, respectively, it is suggested that under topo II inhibition, the M phase checkpoint operates through an inability for chromosome segregation.
A novel antimicrobial peptide from the loach, Misgurnus anguillicaudatus
Authors: Park Chan Bae , Lee Jae Hyun , Park In Yup , Kim Mi Sun , Kim Sun Chang
Published: July 2002

A novel antimicrobial peptide, named misgurin, was isolated and characterized from the loach (mudfish), Misgurnus anguillicaudatus. The 21‐amino‐acid peptide with a molecular mass of 2502 Da was purified to homogeneity using a heparin‐affinity column and C18 reverse‐phase and gel‐permeation high‐performance liquid chromatography. The complete amino acid sequence of misgurin, which was determined by an automated amino acid sequencer, was Arg–Gln–Arg–Val–Glu–Glu–Leu–Ser–Lys–Phe–Ser–Lys–Lys–Gly–Ala–Ala–Ala–Arg–Arg–Arg–Lys. Misgurin is a strongly basic peptide which has 5 arginine and 4 lysine residues. Comparison of the amino acid sequence with those of other known antimicrobial peptides revealed that misgurin was a novel antimicrobial peptide. Misgurin showed a strong antimicrobial activity in vitro against a broad spectrum of microorganisms without significant hemolytic activity and was about 6 times more potent than magainin 2. Scanning electron microscopy confirmed that the peptide caused damage to the cell membrane by a pore‐forming mechanism similar to that of magainin 2. This damage occurred at the minimal inhibition concentration (MIC), but at higher concentration than MIC it lysed the cell.
The soluble hyaluronidase from bull testes is a fragment of the membrane‐bound PH‐20 enzyme
Authors: Meyer Michael F , Kreil Günther , Aschauer Heinrich
Published: July 2002

The membrane‐bound PH‐20 hyaluronidase is known to be essential for fertilization. Here we addressed the question whether the soluble hyaluronidase from bull teste is related to the PH‐20 polypeptide. The sequence of the membrane‐bound PH‐20 hyaluronidase from bovine sperm was determined via cDNA cloning. In parallel, from a commercial preparation of bovine hyaluronidase the major 60‐kDa form was purified to apparent homogeneity. The soluble enzyme was digested with two different proteases and with cyanogen bromide and the amino acid sequence of 44 different fragments was determined. All the peptide sequences could be aligned to the sequence deduced from the cloned cDNAs. Our results thus show that the soluble 60‐kDa hyaluronidase from bovine testes is a glycoprotein derived from the sperm PH‐20 enzyme. As compared to the primary translation product of the PH‐20 mRNA, it lacks the signal peptide at the amino terminus and 56 amino acids at the carboxyl end. These results demonstrate that the soluble 60‐kDa enzyme is a fragment of the PH‐20 hyaluronidase. It is currently not known whether the soluble testes hyaluronidase has a distinct biological function.
The assimilatory nitrate reductase from the phototrophic bacterium, Rhodobacter capsulatus E1F1, is a flavoprotein
Authors: Blasco R , Castillo F , Martı́nez-Luque M
Published: July 2002

The assimilatory nitrate reductase from the phototrophic bacterium Rhodobacter capsulatus has been purified to electrophoretic homogeneity and its molecular and kinetic parameters determined. The native nitrate reductase is a dimer of 144 kDa composed of two subunits of 46 and 95 kDa. The purified enzyme catalyzes the electron transfer from NADH, reduced bromophenol blue or reduced viologens to nitrate. The nitrate reductase contains 1 mol FAD per mole of enzyme and also reduces cytochrome c or dichlorophenol indophenol with NADH as the electron donor. The diaphorase activity is located in the small subunit.
Prediction of the tertiary structure and substrate binding site of caspase‐8
Authors: Chou Kuo-Chen , Jones David , Heinrikson Robert L
Published: July 2002

The caspases represent a family of sulfhydryl proteases that play important regulatory roles in the cell. The tertiary structure of the protease domain of caspase‐8, also called FLICE, has been predicted by a segment match modeling procedure. First, the atomic coordinates of the catalytic domain of caspase‐3, also called CPP32, a member of the family that is closely related to caspase‐8, were determined based upon the crystal structure of human caspase‐1 (interleukin converting enzyme). Then, the caspase‐3 structure was used as a template for modeling the protease domain of caspase‐8. The resulting structure shows the expected level of similarity with the conformations of caspases‐1 and ‐3 for which crystal structures have been determined. Moreover, the subsite contacts between caspase‐8 and the covalently linked inhibitor, Ac‐DEVD‐aldehyde, are only slightly different from those seen in the caspase‐3 enzyme/inhibitor complex. The model of caspase‐8 can serve as a reference for subsite analysis relative to design of enzyme inhibitors that may find therapeutic application.
Atrial natriuretic peptide stimulates Na+‐dependent Ca2+ efflux from freshly isolated adult rat cardiomyocytes
Authors: Yoshizumi Masanori , Houchi Hitoshi , Tsuchiya Koichiro , Minakuchi Kazuo , Horike Kazuya , Kitagawa Tetsuya , Katoh Itsuo , Tamaki Toshiaki
Published: July 2002

In the present study, we examined the effect of atrial natriuretic peptide (ANP) on Ca2+ efflux from freshly isolated adult rat cardiomyocytes. Rat ANP(1–28) stimulated the efflux of 45Ca2+ from the cells in a concentration‐dependent manner (10−8 M to 10−6 M). The 45Ca2+ efflux was not affected by removal of extracellular Ca2+, but was dependent on the presence of extracellular Na+. In addition, rat ANP(1–28) caused 22Na+ influx into the cells. The 45Ca2+ efflux was also stimulated by C‐type natriuretic peptide‐22 (CNP‐22), but not by rat brain natriuretic peptide‐45 (BNP‐45). It was also observed that both rat ANP(1–28) and CNP‐22 stimulated guanosine 3′,5′‐cyclic monophosphate production within the cells. These results indicate that ANP stimulates Na+‐dependent 45Ca2+ efflux from freshly isolated adult rat cardiomyocytes, probably through Na+/Ca2+ exchange, and that the stimulatory effect of ANP on Ca2+ efflux may be mediated via the natriuretic peptide receptor which has been shown to couple to guanylate cyclase. Since it is reported that Na+/Ca2+ exchange is important in calcium homeostasis within cells, ANP may play a role in the extrusion of intracellular Ca2+ from isolated adult rat cardiomyocytes.
The C. reinhardtii CF1 with the mutation βT168S has high ATPase activity
Authors: Hu Dongli , Strotmann Heinrich , Shavit Noun , Leu Stefan
Published: July 2002

We have generated the mutation T168S in the β subunit of the chloroplast ATP synthase complex of Chlamydomonas reinhardtii by site directed mutagenesis and chloroplast transformation. CF1 and the α3β3γ complex of this mutant strain were isolated and their enzymatic activities were characterized and compared to those of the corresponding wild type complexes. Without activation the mutant CF1 exhibits MgATPase activity with at least 10 times higher rates than the wild type enzyme. The MgATPase activity could be stimulated to some extent by methanol, but less by ethanol and octylglucoside. The α3β3γ complex had an even higher MgATPase activity, which was only slightly enhanced by ethanol or methanol. The ATPase activities of the mutant complexes, like those of the wild type complexes, displayed a sharp concentration optimum for Mg2+. Free ADP inhibited neither the mutant nor the wild type ATPase significantly. Azide, which strongly inhibited the ATPase activity of the wild type enzyme, inhibited the mutant enzyme only at an about 30 times higher concentration suggesting that the mutation T168S prevents trapping of a tightly bound MgADP by a catalytic site that regulates chloroplast ATPase activity. The mutant cells grew photoautotrophically at a growth rate of about 50%. Similar to the wild type the cells survived on minimal medium in the dark. Under heterotrophic conditions with acetate as energy and carbon source the mutant cells grew much faster than the wild type cells, but the chlorophyll content per cell decreased dramatically.
Glycosylation and thermodynamic versus kinetic stability of horseradish peroxidase
Authors: Tams Jeppe W , Welinder Karen G
Published: July 2002

The influence of N‐linked glycans on the stability of glycoproteins has been studied using horseradish peroxidase isoenzyme C (HRP), which contains eight asparagine‐linked glycans. HRP was deglycosylated (d‐HRP) with trifluoromethanesulfonic acid and purified to an enzymatically active homogeneous protein containing (GlcNAc)2 glycans. The thermal stability of HRP and d‐HRP at pH 6.0, measured by residual activity, was indistinguishable and showed transition midpoints at 57°C, whereas the unfolding in guanidinium chloride at pH 7.0, 23°C was 2–3‐fold faster for d‐HRP than for HRP. The results are compatible with a glycan‐induced decrease in the dynamic fluctuation of the polypeptide chain.
Molecular cloning, genomic characterization and expression of novel human α1A‐adrenoceptor isoforms
Authors: Chang David J , Chang Thomas K , Yamanishi Susan S , Salazar F.H.Rick , Kosaka Alan H , Khare Reena , Bhakta Sunil , Jasper Jeffrey R , Shieh Ing-Shih , Lesnick John D , Ford Anthony P.D.W , Daniels Donald V , Eglen Richard M , Clarke David E , Bach Chinh , Chan Hardy W
Published: July 2002

We have isolated and characterized from human prostate novel splice variants of the human α1A‐adrenoceptor, several of which generate truncated products and one isoform, α1A‐4, which has the identical splice site as the three previously described isoforms. Long‐PCR on human genomic DNA showed that the α1A‐4 exon is located between those encoding the α1A‐1 and α1A‐3 variants. CHO‐K1 cells stably expressing α1A‐4 showed ligand binding properties similar to those of the other functional isoforms as well as agonist‐stimulated inositol phosphate accumulation. Quantitative PCR analyses revealed that α1A‐4 is the most abundant isoform expressed in the prostate with high levels also detected in liver and heart.
A new family of cytokinin receptors from Cereales
Authors: Kulaeva O.N , Zagranichnaya T.K , Brovko F.A , Karavaiko N.N , Selivankina S.Yu , Zemlyachenko Ya.V , Hall M , Lipkin V.M , Boziev Kh.M
Published: July 2002

The highly specific recognition of a natural cytokinin, trans‐zeatin, by cytokinin‐binding protein (CBP) of 67 kDa from barley leaves was detected with an assay developed on the basis of cytokinin competition in ELISA with anti‐idiotype antibodies (raised against antibodies to zeatin) for complex formation with CBP. Monoclonal antibodies (mAbs) raised against 70 kDa CBP from etiolated maize seedlings cross‐reacted with barley 67 kDa CBP and prevented barley CBP and trans‐zeatin induced activation of transcription elongation directed by RNA polymerase I associated with barley chromatin. One mAb (Z‐6) had an agonistic effect. Maize CBP replaced barley CBP in activation of RNA synthesis with cytokinin in the barley transcription system. Hence, a new family of cytokinin receptors with common functions and immunodeterminants including maize and barley CBPs was found.
Fatty acid‐induced uncoupling of oxidative phosphorylation is partly due to opening of the mitochondrial permeability transition pore
Authors: Więckowski Mariusz R , Wojtczak Lech
Published: July 2002

Addition of myristate at low concentration (30–60 nmol/mg protein) to energized rat liver mitochondria resulted in dissipation of the electric membrane potential which, in Ca2+‐free media, could be partly reversed by carboxyatractyloside but not by cyclosporin A. In contrast, in mitochondria preloaded with Ca2+ this energy‐dissipating effect of fatty acid was partly prevented or reversed by cyclosporin A or ADP. In sucrose media, myristate, but not the protonophore carbonyl cyanide m‐chlorophenylhydrazone, induced swelling of Ca2+‐loaded mitochondria which was inhibited by cyclosporin A and ADP. We conclude that long‐chain fatty acids may induce opening of the mitochondrial permeability transition pore not only because of their protonophoric effect mediated by mitochondrial anion carriers [Skulachev, V.P., FEBS Lett. 294 (1991) 158–162; Więckowski, M.R. and Wojtczak, L., Biochem. Biophys. Res. Commun. (1997) 232, 414–417] but also by a direct interacton with the pore assembly.
Activation of caspases triggered by cytochrome c in vitro1
Authors: Pan Guoha , Humke Eric W , Dixit Vishva M
Published: July 2002

Previous studies have shown that Apaf‐1 and caspase‐9 in the presence of cytochrome c and dATP can form an initiating complex for an apoptotic protease cascade. We have developed a cytochrome c‐dependent in vitro system in which caspases downstream of this initiation complex are activated. The activation of caspase‐9 from zymogen form to active dimeric protease requires intrinsic enzymatic activity. In contrast, caspase‐3 and caspase‐7 zymogens are proteolytically processed by active caspase‐9. Activation of the above caspases is blocked by a dominant negative form of caspase‐9. The in vitro system displays surprising specificity in that other caspases, including 1, 2, 4, 8, 10, and 13, are not activated.
The cloning expression and tissue distribution of human PP2Cβ1
Authors: Marley Anna E. , Kline Adam , Crabtree Garry , Sullivan Jane E. , Beri Raj K.
Published: July 2002

We have cloned a novel PP2Cβ isoform from a human liver cDNA library which codes for a protein homologous to other mammalian PP2Cβs at the N‐terminus but with an extended C‐terminus that is unique amongst the PP2Cs. The protein expressed in E. coli is indistinguishable from human recombinant PP2Cα in its cation dependence and insensitivity to okadaic acid. Northern blot analysis of PP2Cβ along with that of PP2Cα shows that human PP2Cs are widely expressed and are most abundant in heart and skeletal muscle.
The role of subunit composition on prepulse facilitation of the cardiac L‐type calcium channel
Authors: Dai Shuiping , Klugbauer Norbert , Zong Xiangang , Seisenberger Claudia , Hofmann Franz
Published: July 2002

Facilitation of calcium current by depolarizing prepulses has been observed in many cells including cardiac muscle. The mechanism underlying prepulse facilitation is controversial with respect to the requirements of channel subunits and cAMP kinase. We found that coexpression of the cardiac α1C‐a subunit with the cardiac β2a subunit significantly promotes the facilitation of I
Ba by strong depolarizing prepulses. The magnitude of I
Ba facilitation depended on the voltage potential of the prepulse and the interval duration between prepulse and test pulse. Prepulse facilitation was not affected by coexpression of AKAP79 and conditions favoring cAMP‐dependent phosphorylation. Prepulse facilitation was also observed in cells expressing an α1C‐a subunit which was truncated at residue 1733 removing the cAMP kinase site at Ser‐1928. Facilitation was abolished by coexpression of the α2δ‐1 or α2δ‐3 subunit. We conclude that the expressed α1C‐a β2a complex is sufficient to support prepulse facilitation. Facilitation is prevented by coexpression of the α2δ subunit.
Transgenic UCP1 in white adipocytes modulates mitochondrial membrane potential
Authors: Baumruk Filip , Flachs Pavel , Horáková Milada , Floryk Daniel , Kopecký Jan
Published: July 2002

To test if mitochondrial uncoupling in white adipocytes is responsible for obesity resistance of the aP2‐Ucp transgenic mice expressing ectopic uncoupling protein 1 (UCP1) in white fat, mitochondrial membrane potential (ΔΨ
m) was estimated by flow cytometry in adipocytes isolated from gonadal fat. Ectopic UCP1 (approximately 0.8 mol UCP1/mol respiratory chain) decreased the ΔΨ
m and rendered the potential sensitive to GDP and fatty acids. These ligands of UCP1 had no effect on ΔΨ
m in white adipocytes from non‐transgenic mice, suggesting that the function of endogenous UCP2 in adipocytes was not affected. The results support the hypothesis that mitochondrial uncoupling in white fat may prevent development of obesity.
Enhanced mitochondrial biogenesis is associated with increased expression of the mitochondrial ATP‐dependent Lon protease
Authors: Luciakova Katarina , Sokolikova Barbora , Chloupkova Maria , Nelson B.Dean
Published: July 2002

Rats bearing the Zajdela hepatoma tumor and T3‐treated hypothyroid rats were used to study the role of protein degradation in the process of mitochondrial biogenesis. It was shown that the activity, protein and mRNA levels of the ATP‐dependent Lon protease increased in rapidly growing Zajdela hepatoma cells. The increase in the rate of mitochondrial biogenesis by thyroid hormone was similarly accompanied by enhanced expression of the Lon protease. The results imply that mitochondrial biogenesis in mammalian cells is, at least partially, regulated by the matrix Lon protease.
Dysfunctions of the epididymis as a result of primary carnitine deficiency in juvenile visceral steatosis mice
Authors: Toshimori Kiyotaka , Kuwajima Masamichi , Yoshinaga Kazuya , Wakayama Tomohiko , Shima Kenji
Published: July 2002

The juvenile visceral steatosis mutant mice serve as an animal model of primary carnitine deficiency, classified as the sudden infant death syndrome. The defect in carnitine uptake was recently found to be due to a defect in the carnitine transporter gene. We herein report, for the first time, the characteristics of epididymal dysfunction in juvenile visceral steatosis mice. At 8–9 weeks of age, the epididymis was deformed and weight was significantly increased. Histologically, the duct of the proximal epididymis was dilated due to the accumulation of an unusually high level of spermatozoa. Spermatozoa were extravasated from the epididymal duct into the stroma. In contrast, the duct of the distal epididymis was constricted and contained no spermatozoa. Thus, the epididymal disorder causes obstructive azoospermia, leading to infertility.
Recombinant human uncoupling protein‐3 increases thermogenesis in yeast cells
Authors: Hinz W. , Faller B. , Grüninger S. , Gazzotti P. , Chiesi M.
Published: July 2002

The long form of human uncoupling protein‐3 (hUCP3L) is highly homologous to thermogenin (UCP1), the uncoupling protein of brown fat mitochondria, but is expressed predominantly in skeletal muscle. Its putative role is to regulate the coupling efficiency of oxidative phosphorylation and thus thermogenesis in skeletal muscle, a major thermogenic tissue in higher mammals. To study the functional relevance of hUCP3L, the protein was expressed in yeast cells under the control of the galactose promoter. Expression of hUCP3L induced a series of phenotype changes in the yeast cells. The cellular growth and the mitochondrial membrane potential were both diminished. The portion of cellular respiration coupled to oxidative phosphorylation decreased from 57% to 11% (P<0.001) and the cellular heat production, as measured by direct microcalorimetry, was increased by 33.3±3.2% (P<0.001) after induction of UCP3L. These observations demonstrate for the first time the intrinsic thermogenic properties of hUCP3L in intact cells.
Human milk lactoferrin binds two DNA molecules with different affinities
Authors: Kanyshkova Tat'yana G , Semenov Dmitry V , Buneva Valentina N , Nevinsky Georgy A
Published: July 2002

Evidence is presented that lactoferrin (LF), an Fe3+‐binding glycoprotein, possesses two DNA‐binding sites with different affinities for specific oligonucleotides (ODNs) (K
d1=8 nM; K
d2∽0.1 mM). The high affinity site became labeled after incubation with affinity probes for DNA‐binding sites; like the antibacterial and polyanion‐binding sites, this site was shown to be located in the N‐terminal domain of LF. Interaction of heparin with the polyanion‐binding site inhibits the binding of ODNs to both sites. These data suggest that the DNA‐binding sites of LF coincide or overlap with the known polyanion and antimicrobial domains of the protein.
Circadian‐regulated expression of a nuclear‐encoded plastid σ factor gene (sigA) in wheat seedlings
Authors: Morikawa Kazuya , Ito Shinji , Tsunoyama Yuichi , Nakahira Yoichi , Shiina Takashi , Toyoshima Yoshinori
Published: July 2002

The activity of a light‐responsive psbD promoter in plastids is known to be regulated by a circadian clock. However, the mechanism of the circadian regulation of the psbD light‐responsive promotor, which is recognized by an Escherichia coli‐type RNA polymerase, is not yet known. We examined the time course of mRNA accumulation of two E. coli‐type RNA polymerase subunit genes, sigA and rpoA, under a continuous light condition after 12 h light/12 h dark entrainment. Accumulation of the sigA mRNA was found to be regulated by a circadian clock, while rpoA mRNA did not show any significant oscillation throughout the experiment.
Sticholysin II, a cytolysin from the sea anemoneStichodactyla helianthus, is a monomer‐tetramer associating protein
Authors: de los Rı́os Vivian , Mancheño José M. , Martı́nez del Pozo Alvaro , Alfonso Carlos , Rivas Germán , Oñaderra Mercedes , Gavilanes José G.
Published: July 2002

Sticholysin II (Stn‐II) is a pore‐forming cytolysin. Stn‐II interacts with several supports for size exclusion chromatography, which results in an abnormal retardation precluding molecular mass calculations. Sedimentation equilibrium analysis has revealed that the protein is an associating system at neutral pH. The obtained data fit a monomer‐tetramer equilibrium with an association constantKc4of 109M−3. The electrophoretic pattern of Stn‐II treated with different cross‐linking reagents, in a wide range of protein concentrations, corroborates the existence of tetrameric forms in solution. A planar configuration of the four monomers, C4 or D2 symmetry, is proposed from modelling of the cross‐linking data.
Molecular characterization of Vig4/Vrg4 GDP‐mannose transporter of the yeast Saccharomyces cerevisiae
Authors: Abe Masato , Hashimoto Hitoshi , Yoda Koji
Published: July 2002

Saccharomyces cerevisiae Vig4/Vrg4 protein is a Golgi membrane protein which has multiple transmembrane domains and is essential for transport of GDP‐mannose across the Golgi membrane. By immunoprecipitation of detergent‐solubilized tagged protein, we found that this protein exists as oligomer. Two mutants vig4‐1 and vig4‐2 had amino acid substitutions in the C‐terminal region, Ala286Val and Ser278Cys, respectively. In accord with these mutations, trimming of the C‐terminal hydrophobic part close to the region impaired the function and traffic of the proteins from the endoplasmic reticulum to the Golgi compartments.
A new matrix protein family related to the nacreous layer formation of Pinctada fucata
Authors: Samata Tetsuro , Hayashi Nakanobu , Kono Makiko , Hasegawa Kyoko , Horita Chie , Akera Syusaku
Published: July 2002

We have isolated a new matrix protein family (N16) which is specific to the nacreous layer of the Japanese pearl oyster, Pinctada fucata, and have cloned and characterized the cDNAs coding for the components. Analysis of the deduced amino acid sequence revealed that N16 showed no definitive homology with other proteins. The in vitro studies of the crystallization clarified that N16 induced aragonite crystals when fixed on the substrate but inhibited crystal formation without it. The aragonite crystals showed platy morphology different from those formed inorganically, and long intervals of incubation resulted in crystalline layers highly similar to the nacreous layer.
1‐Methyl‐4‐phenyl‐2,3‐dihydropyridinium is transformed by ubiquinone to the selective nigrostriatal toxin 1‐methyl‐4‐phenylpyridinium
Authors: Shi Honglian , Noguchi Noriko , Xu Yuexian , Niki Etsuo
Published: July 2002

We have studied the interaction of coenzyme Q with 1‐methyl‐4‐phenyl‐1,2,3,6‐tetrahydropyridine (MPTP) and its metabolites, 1‐methyl‐4‐phenyl‐2,3‐dihydropyridinium (MPDP+) and 1‐methyl‐4‐phenylpyridinium (MPP+), the real neurotoxin to cause Parkinson's disease. Incubation of MPTP or MPDP+ with rat brain synaptosomes induced complete reduction of endogenous ubiquinone‐9 and ubiquinone‐10 to corresponding ubiquinols. The reduction occurred in a time‐ and MPTP/MPDP+ concentration‐dependent manner. The reduction of ubiquinone induced by MPDP+ went much faster than that by MPTP. MPTP did not reduce liposome‐trapped ubiquinone‐10, but MPDP+ did. The real toxin MPP+ did not reduce ubiquinone in either of the systems. The reduction by MPTP but not MPDP+ was completely prevented by pargyline, a type B monoamine oxidase (MAO‐B) inhibitor, in the synaptosomes. The results indicate that involvement of MAO‐B is critical for the reduction of ubiquinone by MPTP but that MPDP+ is a reductant of ubiquinone per se. It is suggested that ubiquinone could be an electron acceptor from MPDP+ and promote the conversion from MPDP+ to MPP+ in vivo, thus accelerating the neurotoxicity of MPTP.
Distribution of Mahogany/Attractin mRNA in the rat central nervous system
Authors: Lu Xin-Yun , Gunn Teresa M. , Shieh Kun-Ruey , Barsh Gregory S. , Akil Huda , Watson Stanley J.
Published: July 2002

The Mahogany/Attractin gene (Atrn) has been proposed as a downstream mediator of Agouti signaling because yellow hair color and obesity in lethal yellow (A
y) mice are suppressed by the mahogany (Atrn
mg) mutation. The present study examined the distribution of Atrn mRNA in the brain and spinal cord by in situ hybridization. Atrn mRNA was found widely distributed throughout the central nervous system, with high levels in regions of the olfactory system, some limbic structures, regions of the brainstem, cerebellum and spinal cord. In the hypothalamus, Atrn mRNA was found in specific nuclei including the suprachiasmatic nucleus, the supraoptic nucleus, the medial preoptic nucleus, the paraventricular hypothalamic nucleus, the ventromedial hypothalamic nucleus, and the arcuate nucleus. These results suggest a broad spectrum of physiological functions for the Atrn gene product.
SMAP‐29: a potent antibacterial and antifungal peptide from sheep leukocytes
Authors: Skerlavaj Barbara , Benincasa Monica , Risso Angela , Zanetti Margherita , Gennaro Renato
Published: July 2002

SMAP‐29 is a cathelicidin‐derived peptide deduced from sheep myeloid mRNA. The C‐terminally amidated form of this peptide was chemically synthesized and shown to exert a potent antimicrobial activity. Antibiotic‐resistant clinical isolates highly susceptible to this peptide include MRSA and VREF isolates, that are a major worldwide problem, and mucoid Pseudomonas aeruginosa associated with chronic respiratory inflammation in CF patients. In addition, SMAP‐29 is also active against fungi, including Cryptococcus neoformans isolated from immunocompromised patients. SMAP‐29 causes significant morphological alterations of the bacterial surfaces, as shown by scanning electron microscopy, and is also hemolytic against human, but not sheep erythrocytes. Its potent antimicrobial activity suggests that this peptide is an excellent candidate as a lead compound for the development of novel antiinfective agents.
Supplementary calcium in prevention of pre‐eclampsia
Authors: Niromanesh S , Laghaii S , Mosavi‐Jarrahi A
Published: July 2002

Objective:To study the effect of calcium supplementation on reduction of pre‐eclampsia in Iranian women at high risk of pre‐eclampsia.Methods:Thirty pregnant women at high risk of developing pre‐eclampsia were randomized to 2 g of daily calcium and placebo. Subjects and investigators were blinded to treatment allocation. The inclusion criteria were positive rollover test, having at least one risk factor for pre‐eclampsia, between 28 and 32 weeks of pregnancy, and blood pressure less than 140/90 (mmHg). Exclusion criteria were having any chronic condition. Pre‐eclampsia was defined as systolic/diastolic blood pressure over 140/90 plus proteinuria. All the subjects were followed up to delivery.Result:A sevenfold reduction in the occurrence of pre‐eclamsia were seen among the calcium group compared with the placebo group (7 out of 15 developed pre‐eclampsia in control group vs. 1 out of 15 in calcium group,P=0.014). No major effect on pregnancy induced hypertension was seen (66% in placebo and 76% in calcium group developed hypertension) but the onset of hypertension was delayed 3 weeks in the calcium group. A longer duration of pregnancy was seen in calcium than placebo (mean±S.D.=37±2 for calcium and 34±2 for placebo,P<0.05). Infants born to the calcium group, on average, were 552 g heavier than infants born to the placebo group,P<0.05.Conclusion:Calcium supplementation is beneficial for preventing pre‐eclampsia among Iranian women at high risk of developing pre‐eclampsia.
Teaching safe sex in school
Authors: Short R.
Published: July 2002

Objective: To teach safe sex practices to adolescents in school, before they start to become sexually active, using peer group education. Method: To send young medical students back to their old schools to do the teaching, and to get them to make videos suitable for showing to teenage audiences that can be widely circulated to all schools. Results: The program has been running in Australia since 1992, and has proved highly popular with school teachers, school children, and particularly with medical students. We are now working with medical schools in Beijing and Shanghai, at the invitation of the Chinese Ministry of Health, to see if we can adapt our program to a very different cultural setting. Conclusion: Educating children about Safe Sex is one of the most effective ways of postponing their onset of sexual activity. It is also the best investment that we can make to ensure people's future reproductive health; if they start right, there is every hope that they will stay right.
Building operations management theory through case and field research
Authors: Meredith Jack
Published: July 2002

Case and field research studies continue to be rarely published in operations management journals, in spite of increased interest in reporting such types of studies and results. This paper documents the advantages and rigor of case/field research and argues that these methods are preferred to the more traditional rationalist methods of optimization, simulation, and statistical modeling for building new operations management theories. In the process of describing the constructs of inference and generalizability with reference to case research, we find the existing definitions inadequate and thus extend and refine them to better discriminate between alternate research methodologies. We also elaborate on methods for increasing the generalizability of both rationalist and case/field research studies. A major conclusion is that these alternate research methods are not mutually exclusive and, if combined, can offer greater potential for enhancing new theories than either method alone.
The relationship between total quality management practices and operational performance
Authors: Samson Danny , Terziovski Mile
Published: July 2002

Total quality management (TQM) has been a widely applied process for improving competitiveness around the world, but with mixed success. A review of the literature revealed gaps in research in this area of quality/operations management, particularly in the area of empirical testing of the effectiveness of TQM implementation. The aim of this study was to examine the total quality management practices and operational performance of a large number of manufacturing companies in order to determine the relationships between these practices, individually and collectively, and firm performance. We used a large data base of 1200 Australian and New Zealand manufacturing organisations. The reliability and validity (construct, content, criterion) of the practice and performance measures were evaluated. Our study showed that the relationship between TQM practice and organisational performance is significant in a cross‐sectional sense, in that TQM practice intensity explains a significant proportion of variance in performance. Some but not all of the categories of TQM practice were particularly strong predictors of performance. The categories of leadership, management of people and customer focus were the strongest significant predictors of operational performance. This is consistent with literature findings that behavioural factors such as executive commitment, employee empowerment and an open culture can produce competitive advantage more strongly than TQM tools and techniques such as process improvement, benchmarking, and information and analysis.
Contribution of disc degeneration to osteophyte formation in the cervical spine: a biomechanical investigation
Authors: Kumaresan Srirangam , Yoganandan Narayan , Pintar Frank A. , Maiman Dennis J. , Goel Vijay K.
Published: July 2002

Cervical spine disorders such as spondylotic radiculopathy and myelopathy are often related to osteophyte formation. Bone remodeling experimental—analytical studies have correlated biomechanical responses such as stress and strain energy density to the formation of bony outgrowth. Using these responses of the spinal components, the present study was conducted to investigate the basis for the occurrence of disc‐related pathological conditions. An anatomically accurate and validated intact finite element model of the C4‐C5‐C6 cervical spine was used to simulate progressive disc degeneration at the C5‐C6 level. Slight degeneration included an alteration of material properties of the nucleus pulposus representing the dehydration process. Moderate degeneration included an alteration of fiber content and material properties of the anulus fibrosus representing the disintegrated nature of the anulus in addition to dehydrated nucleus. Severe degeneration included decrease in the intervertebral disc height with dehydrated nucleus and disintegrated anulus. The intact and three degenerated models were exercised under compression, and the overall force—displacement response, local segmental stiffness, anulus fiber strain, disc bulge, anulus stress, load shared by the disc and facet joints, pressure in the disc, facet and uncovertebral joints, and strain energy density and stress in the vertebral cortex were determined. The overall stiffness (C4‐C6) increased with the severity of degeneration. The segmental stiffness at the degenerated level (C5‐C6) increased with the severity of degeneration. Intervertebral disc bulge and anulus stress and strain decreased at the degenerated level. The strain energy density and stress in vertebral cortex increased adjacent to the degenerated disc. Specifically, the anterior region of the cortex responded with a higher increase in these responses. The increased strain energy density and stress in the vertebral cortex over time may induce the remodeling process according to Wolff's law, leading to the formation of osteophytes. © 2001 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.
Addiction and schizophrenia
Authors: Batel P.
Published: July 2002

Epidemiologic studies in the general population and those based on the clinical assessment of schizophrenic populations have revealed a high degree of overlap between schizophrenia and addictive disorders. The abuse of psychoactive substances (including alcohol) throughout life is so frequent (50%) that the possibility of a specific link inevitably arises. Various hypotheses have been suggested to explain the high co-morbidity between schizophrenia and addiction: 1) The social-environmental hypothesis has been developed but studies have provided poor evidence to validate it. 2) The possible shared biological vulnerability between schizophrenia and addictions led researchers to explore common genetic determinants and study the involvement of the dopaminergic and opioid systems in the aetiology of both schizophrenia and the abuse of and dependence on psychoactive drugs. 3) Finally, the theory of self-medication suggests that schizophrenics may be attempting to counter the deficit linked to their disorders by using the substances they take or their dependency-type behaviour to cope with their emotional problems. The clinical profile of schizophrenic addicts does seem to display some distinctive features, such as the high level of depressive co-morbidity, very high nicotine and alcohol dependence, with a very poor prognosis. These patients are difficult to manage; the possibility of pharmacologic interactions between the substances they are taking and neuroleptic medication calls for prudence, and their compliance is also poor. Addictive disorders in schizophrenics are currently a topic of active research intended to lead to identifying specific treatments. The early identification of addictive disorders in schizophrenics should make it possible to limit their development and improve the prognosis.
Clinical trials update: highlights of the scientific sessions of the American Heart Association year 2000: Val HeFT, COPERNICUS, MERIT, CIBIS‐II, BEST, AMIOVIRT, V‐MAC, BREATHE, HEAT, MIRACL, FLORIDA, VIVA and the first human cardiac skeletal muscle myoblast transfer for heart failure
Authors: Thackray Simon D.R. , Witte Klaus K.A. , Khand Aleem , Dunn Anita , Clark Andrew L. , Cleland John G.F.
Published: July 2002

This article continues a series of reports summarising recent research developments pertinent to the topic of heart failure. This is a summary of presentations made at scientific sessions of the American Heart Association in November 2000. Clinical studies of particular interest to people caring for patients with heart failure include Val‐HeFT, AMIOVIRT and V‐MAC. New data from β‐blockers trials are reviewed, highlights from some important developments in post‐infarction care, including MIRACL and FLORIDA, discussed and results of some early studies of gene therapy reported.