bluuebunny/crossref_metadata_2025 huggingface dataset:
Occurrence, horizontal transfer and degeneration of VDE intein family in Saccharomycete yeasts
Authors: Okuda Yoshihiro , Sasaki Daisuke , Nogami Satoru , Kaneko Yoshinobu , Ohya Yoshikazu , Anraku Yasuhiro
Published: May 2003

VDE is a homing endonuclease gene originally discovered as an intervening element in VMA1s of Saccharomyces cerevisiae. There have been two independent subfamilies of VDE, one from S. cerevisiae strain X2180‐1A and the other from Saccharomyces sp. DH1‐1A in the host VMA1 gene, and they share the identity of 96.3%. In order to search the occurrence, intra/interspecies transfer and molecular degeneration of VDE, complete sequences of VMA1 in 10 strains of S. cerevisiae, eight species of saccharomycete yeasts, Candida glabrata and Kluyveromyces lactis were determined. We found that six of 10 S. cerevisiae strains contain VDEs 99.7–100% identical to that of the strain X2180‐1A, one has no VDE, whereas the other three harbour VDEs 100% identical to that of the strain DH1‐1A. S. carlsbergensis has two VMA1s, one being 99.8% identical to that of the strain X2180‐1A with VDE 100% identical to that of the strain DH1‐1A and the other containing the same VMA1 in S. pastorianus with no VDE. This and other evidence indicates that intra/interspecies transmissions of VDEs have occurred among saccharomycete yeasts. Phylogenetic analyses of VMA1 and VDE suggest that the S. cerevisiae VDEs had branched earlier than other VDEs from an ancestral VDE and had invaded into the host loci as relatively late events. The two VDEs seemed to degenerate in individual host loci, retaining their splicing capacity intact. The degeneration of the endonuclease domains was distinct and, if compared, its apparent rate was much faster than that of the protein‐splicing domains. The VMA1 gene sequences determined in this study have been deposited in the GenBank data library under the Accession Nos shown in Table 1. Copyright © 2003 John Wiley & Sons, Ltd.
Guanidine reduces stop codon read‐through caused by missense mutations in SUP35 or SUP45
Authors: Bradley Michael E. , Bagriantsev Sviatoslav , Vishveshwara Namitha , Liebman Susan W.
Published: May 2003

Sup35 and Sup45 are essential protein components of the Saccharomyces cerevisiae translation termination factor. Yeast cells harbouring the [PSI+] prion form of Sup35 have impaired stop codon recognition (nonsense suppression). It has long been known that the [PSI+] prion is not stably transmitted to daughter cells when yeast are grown in the presence of mM concentrations of guanidine hydrochloride (GuHCl). In this paper, Mendelian suppressor mutations whose phenotypes are likewise hidden during growth in the presence of millimolar GuHCl are described. Such GuHCl‐remedial Mendelian suppressors were selected under conditions where [PSI+] appearance was limiting, and were caused by missense mutations in SUP35 or SUP45. Clearly, antisuppression caused by growth in the presence of GuHCl is not sufficient to distinguish missense mutations in SUP35 or SUP45, from [PSI+]. However, the Mendelian and prion suppressors can be distinguished by subsequent growth in the absence of GuHCl, where only the nonsense suppression caused by the [PSI+] prion remains cured. Recent reports indicate that GuHCl blocks the inheritance of [PSI+] by directly inhibiting the activity of the protein remodelling factor Hsp104, which is required for the transmission of [PSI+] from mother to daughter cells. However, the nonsense suppressor activity caused by the GuHCl‐remedial sup35 or sup45 suppressors does not require Hsp104. Thus, GuHCl must antisuppress the sup35 and sup45 mutations via an in vivo target distinct from Hsp104. Copyright © 2003 John Wiley & Sons, Ltd.
The conformational flexibility of 5,6,7,8‐tetrahydrobiopterin and 5,6,7,8‐tetrahydroneopterin: a molecular dynamical simulation
Authors: Estelberger Willibald , Mlekusch Walter , Reibnegger Gilbert
Published: May 2003

5,6,7,8‐Tetrahydrobiopterin is an essential cofactor of diverse enzymes. Of the eight possible stereoisomers, only the 6R,1′R,2′S‐configuration is biologically active. Other stereoisomers, as well as other reduced pterins such as, e.g. 5,6,7,8‐tetrahydroneopterin, fail to exhibit significant cofactor activity. Different theoretical models (molecular mechanics, semi‐empirical quantum chemical calculations) investigating the stereostructure of tetrahydrobiopterin have yielded diverging answers. It has been claimed on the basis of semi‐empirical quantum chemical calculations that conformational properties, and thus particular features in overall shape, might be responsible for the unique biological properties of natural tetrahydrobiopterin in contrast, e.g. to 6R,1′S,2′R‐5,6,7,8‐tetrahydroneopterin. Molecular dynamical simulations of both molecules at realistic temperatures demonstrate, however, that they possess sufficient conformational flexibility as to render questionable any biological significance of mere conformational properties.
Photoreduction of silicomolybdate in chloroplasts by agents accelerating the deactivation reactions of the water‐oxidizing system
Authors: Samuilov Vitaly D. , Barsky Eugene L. , Gubanova Olga N. , Klimov Vyacheslav V. , Kozlov Yury N.
Published: May 2003

Uncouplers of photosynthetic phosphorylation, CCCP, TTFB and PCP, inhibited light‐induced O2evolution in the Hill reaction with SiMo (I50∼20, 3 and 45μM, respectively), but only insignificantly diminished SiMo photoreduction by pea chloroplasts. The same properties were exhibited by the ADRY agent ANT2p. CCCP, TTFB and PCP are oxidizable compounds with redox potentials of +1.17, +1.18 and +1.09 V (pH 6.0), as determined by cyclic voltammetry. Similarly to NH2OH, the tested uncouplers can apparently serve as electron donors for photosystem II.
Susceptibility of phospholipids of oxidizing LDL to enzymatic hydrolysis modulates uptake by P388D1 macrophage‐like cells
Authors: Fyrnys Beatrix , Blencowe Christopher , Deigner Hans-Peter
Published: May 2003

Addition of the phospholipids 1‐O‐hexadecyl‐2‐arachidonoyl‐sn‐glycero‐3‐phosphocholine (PLE) and 1‐O‐hexadecyl‐2‐desoxy‐2‐amino‐arachidonoyl‐sn‐glycero‐3‐phosphocholine (PLA) to [125I]LDL and subsequent Cu2+‐induced oxidation result in significant differences in protein modification and uptake by P388D1 macrophage‐like cells. PLE‐treated LDL is ingested at a 1.27‐fold rate compared to PLE‐treated LDL and displays enhanced electrophilic mobility. Similar results (1.43‐fold enhanced uptake of LDL preloaded with PLE) are obtained when the uptake of phospholipid‐enriched oxLDL particles are examined. The preference for ingestion as well as protein modification of both preparations is, however, reversed under experimental conditions allowing diffusion and inactivation of a fraction of the peroxidation products. These findings suggest that LDL‐associated PAF‐acetylhydrolase can exert a dual role and, to be protective to LDL, require an appropriate microenvironment, capable of binding certain species of oxidatively fragmented lipids.
The widely used anesthetic agent propofol can replace α‐tocopherol as an antioxidant
Authors: Aarts Leon , van der Hee Regine , Dekker Ingrid , de Jong Jan , Langemeijer Han , Bast Aalt
Published: May 2003

The cell membrane is protected against lipid peroxidation through endogenous antioxidants such as the lipid soluble α‐tocopherol. The anesthetic agent propofol (2,6‐diisopropylphenol) has a chemical structure which is similar to α‐tocopherol, since it also contains a phenolic OH‐group. The transient protection of GSH against lipid peroxidation in control liver microsomes is not observed in microsomes deficient in α‐tocopherol. Introducing propofol (2 and 5 μM) restored the protective effect of GSH. Similar to the control microsomes the GSH‐protective effect did not occur in previously heated microsomes. These results suggest that propofol acts similarly to α‐tocopherol as a chain breaking antioxidant in liver microsomal membranes.
Folding intermediates are involved in genetic diseases?
Authors: Bychkova Valentina E. , Ptitsyn Oleg B.
Published: May 2003

Recent experimental data show that some human genetic diseases are due to mutations in proteins which influence their trafficking and lead to retaining of proteins in the endoplasmic reticulum or their unproper processing. In this paper a hypothesis is proposed that these mutations are connected with an incomplete protein folding, blocking it at the stage of the kinetic molten globule or even earlier. If so, the specific drugs against these diseases may be ligands and other factors which facilitate the correct protein folding.
Viral Qβ RNA as a high expression vector for mRNA translation in a cell‐free system
Authors: Katanaev Vladimir L. , Kurnasov Oleg V. , Spirin Alexander S.
Published: May 2003

Dihydrofolate reductase (DHFR) mRNA was inserted into Qβ phage RNA instead of its coat protein cistron. Translation of this recombinant mRNA in the Escherichia coli cell‐free system resulted in the synthesis of DHFR, which was two orders of magnitude higher than that in the case of translation of the control DHFR mRNA. Additionally, it resulted in a significantly enhanced synthesis of Qβ replicase as compared with its synthesis when the original Qβ RNA was used.
A circularly permuted α‐amylase‐type α/β‐barrel structure in glucan‐synthesizing glucosyltransferases
Authors: MacGregor E.Ann , Jespersen Hans M. , Svensson Birte
Published: May 2003

A motif of amino acid residues, located at the active site and specific β‐strands in a‐amylases, is recognized in α‐1,3‐ and α‐1,6‐glucan‐synthesizing glucosyltransferases, leading to the conclusion that these enzymes contain an α/β‐barrel closely related to the (β/α)8‐fold of the α‐amylase superfamily. The secondary structure elements of the transferase barrel, however, are circularly permuted to start with an α‐helix equivalent to helix 3 in the α‐amylases. Thus, the transferase counterpart of the long third β → α connection — constituting a domain in the α‐amylases — is divided to precede and succeed the barrel. This architectural arrangement may be coupled to sucrose scission and glucosyl transfer. The involvement in the mechanism in glucosyltransferases of active site residues recurring in amylolytic enzymes is discussed.
Ca2+‐dependent inactivation of the class C L‐type Ca2+ channel is a property of the α1 subunit
Authors: Zong Xiangang , Hofmann Franz
Published: May 2003

The stably expressed Ca2+ channel α
1C‐a and α
1C‐b subunit were used to investigate the molecular basis for Ca2+‐dependent inactivation of the L‐type current. The Ba2+ current (I
Ba) of both channels had similar kinetics and inactivated with one time constant of about 400 ms at +20 mV, whereas the Ca2+ current (I
Ca) could be fitted only with a bi‐exponential function. The fast (τ
f) and the slow (τ
s) time constant were about 20 ms and 400 ms, respectively. The inactivation of I
Ca strongly depended on the entry of Ca2+ as shown by prepulses and variation of the intracellular Ca2+ chelator. Coexpression of the α
1C subunits with the auxiliary α
2/δ and β subunits accelerated the voltage‐dependent but not the Ca2+‐dependent inactivation of the channels. These results suggest that the α
1C unit of L‐type Ca2+ channels itself mediates the Ca2+‐dependent inactivation of the current.
Modification of the targeting presequence of the bovine cytochrome P‐450scc precursor lifting tissue‐specific restrictions on its mitochondrial import
Authors: Novikova L.A. , Savel'ev A.S. , Zvyagil'skaya R.A. , Luzikov V.N.
Published: May 2003

It has been found that a recombinant cytochrome P‐450scc precursor supplemented with an extra MRGSH6GIR sequence at the NH2‐terminus (6His‐pP450scc) is imported into isolated rat liver and heart mitochondria as well as into yeast mitochondria. The import is coupled with proteolytic processing of the precursor resulting in the mature size form of cytochrome P‐450scc. Modification of the targeting presequence responsible for its increased positive charge is supposed to lift the previously suggested tissue‐specific restrictions on the pP450scc import into mitochondria.
Mucin‐type glycoprotein from Drosophila melanogaster embryonic cells: characterization of carbohydrate component
Authors: Kramerov A.A. , Arbatsky N.P. , Rozovsky Y.M. , Mikhaleva E.A. , Polesskaya O.O. , Gvozdev V.A. , Shibaev V.N.
Published: May 2003

A secreted glycoprotein (GP) with apparent molecular mass of 90 kDa produced by cultured embryonic cells of Drosophila melanogaster was isolated and partially characterized. GP is enriched by Ser + Thr and Pro residues that constitute up to 30% of the total number of amino acids. An abundant carbohydrate moiety (40% of molecular mass) is mainly represented by vertebrate mucin‐type O‐linked disaccharide units Gal(β1–3)‐GalNAc, occupying about a half of the total number of Ser + Thr residues and rendering the GP molecule high resistance to protease action. A few of N‐glycans are also present in GP. These characteristics allow to consider the Drosophila GP (termed ‘mucin‐D’) as a first representative of invertebrate mucin‐type glycoproteins.
Augmented expression of obese (ob) gene during the process of obesity in genetically obese‐hyperglycemic Wistar fatty (falfa) rats
Authors: Masuzaki Hiroaki , Hosoda Kiminori , Ogawa Yoshihiro , Shigemoto Michika , Satoh Noriko , Mori Kiyoshi , Tamura Naohisa , Nishi Shigeo , Yoshimasa Yasunao , Yamori Yukio , Nakao Kazuwa
Published: May 2003

Expression of the obese (ob) gene is up‐regulated in the adipose tissue in several obese rodent models. To study the regulation of the ob gene expression during the development of obesity, we examined the ob gene expression in genetically obese‐hyperglycemic Wistar fatty (falfa) rats at several stages of obesity. The ob mRNA levels in the adipose tissue from Wistar fatty rats was unequivocally augmented and continued to rise in the process of obesity. Furthermore, the ob gene expression in this obese model was much more rapidly enhanced in the mesenteric fat than in the subcutaneous fat. Moreover, the ob gene expression was more greatly augmented in the mesenteric fat than the lipoprotein lipase gene expression. These results suggest the presence of obesity‐linked and region‐specific regulation of the ob gene expression.
NDR family of AGC kinases – essential regulators of the cell cycle and morphogenesis
Authors: Tamaskovic Rastislav , Bichsel Samuel J. , Hemmings Brian A.
Published: May 2003

The nuclear Dbf2‐related (NDR) family of protein serine/threonine kinases comprises mammalian NDR and large tumor suppressor (LATS) kinases, their orthologs from Drosophila melanogaster and Caenorhabditis elegans, and a number of related kinases from yeast and plants. The members of this family were independently implicated in various aspects of the control of cell division and morphogenesis. They are crucial regulators of the actin and tubulin cytoskeletal organization during polarized growth and cytokinesis in yeast. Furthermore, they are key players in control of proliferation and morphology of many cell types in D. melanogaster and C. elegans. In mammalians, the LATS kinase is a tumor suppressor, negatively regulating the cyclin‐dependent kinase CDK1, cell proliferation rate, and modulating cell survival.
Skeletal muscle mitochondrial oxidative capacity and uncoupling protein 3 are differently influenced by semistarvation and refeeding
Authors: Crescenzo R , Mainieri D , Solinas G , Montani J.P , Seydoux J , Liverini G , Iossa S , Dulloo A.G
Published: May 2003

We investigated, in skeletal muscle mitochondria isolated from semistarved and refed rats, the relation between the protein expression of uncoupling protein 3 (UCP3) and mitochondrial oxidative capacity, assessed as state 4 and state 3 respiration rates in presence of substrates that are either non‐lipids (glutamate, succinate) or lipids (palmitoyl CoA, palmitoylcarnitine). During semistarvation, when whole‐body thermogenesis is diminished, state 3 respiration was lower than in fed controls by about 30% independently of substrate types, while state 4 respiration was lower by 20% only during succinate oxidation, but UCP3 was unaltered. After 5 days of refeeding, when thermogenesis is still diminished, neither state 4, state 3 nor UCP3 were lower than in controls. Refeeding on a high‐fat diet, which exacerbates the suppression of thermogenesis, resulted in a two‐fold elevation in UCP3 but no change in state 4 or state 3 respiration. These results during semistarvation and refeeding, in line with those previously reported for fasting, are not in support of the hypothesis that UCP3 is a mediator of adaptive thermogenesis pertaining to weight regulation, and underscore the need for caution in interpreting parallel changes in UCP3 and mitochondrial oxidative capacity as the reflection of mitochondrial uncoupling by UCP3.
Apoptosis triggered redistribution of caspase‐9 from cytoplasm to mitochondria
Authors: Potokar M , Milisav I , Kreft M , Stenovec M , Zorec R
Published: May 2003

Caspase‐9 is an apoptosis initiator protease activated as a response to the mitochondrial damage in the cytoplasmic complex apoptosome. By fluorescence labelling of proteins, confocal microscopy and subcellular fractionations we demonstrate that caspase‐9 is in the cytoplasm of non‐apoptotic pituitary cells. The activation of apoptosis with rotenone triggers the redistribution of caspase‐9 to mitochondria. Experiments using the general caspase inhibitor z‐VAD.fmk and the specific caspase‐9 inhibitor z‐LEHD.fmk show that the caspase‐9 redistribution is a regulated process and requires the activity of a caspase other than the caspase‐9. We propose that this spatial regulation is required to control the activity of caspase‐9.
The MDM2 RING finger is required for cell cycle‐dependent regulation of its protein expression
Authors: Gu Ling , Ying Haoqiang , Zheng Hongwu , Murray Stephen A. , Xiao Zhi-Xiong Jim
Published: May 2003

The MDM2 oncoprotein is overexpressed in many human tumors and cancers. MDM2 functions as an E3 ligase for p53 and for itself. MDM2 also interacts with the retinoblastoma protein (RB) and the transcription factor E2F1 to promote cell cycle S‐phase entry. Here, we report that MDM2 protein expression is cell cycle‐regulated, which is dependent on its RING finger domain and requires Lys446. We show that MDM2 protein is stabilized at S phase. In addition, overexpression of MDM2 results in stimulation of E2F activity and accumulation of cells in S phase. These data suggest that ubiquitination of MDM2 is cell cycle‐regulated and that MDM2 may play a role in cell cycle progression.
Phosphatidylserine exposure in Fas type I cells is mitochondria‐dependent
Authors: Uthaisang Wanlaya , Nutt Leta K , Orrenius Sten , Fadeel Bengt
Published: May 2003

Previous studies have demonstrated that Fas‐triggered activation of effector caspases and subsequent nuclear apoptosis either is mitochondria‐independent (type I cells) or relies on mitochondrial amplification of the initial stimulus (type II cells). We show herein that Bcl‐2 overexpression in a prototypic type I cell line (SKW6.4) promotes mitochondrial generation of ATP and blocks Fas‐triggered plasma membrane externalization of phosphatidylserine (PS). Moreover, overexpression of Bcl‐2 attenuates macrophage engulfment of Fas‐triggered cells. Fas‐mediated DNA fragmentation, on the other hand, remains unaffected in SKW6.4‐bcl‐2 cells. These studies thus demonstrate that PS externalization and clearance of cell corpses are mitochondria‐dependent events, and show that these events can be dissociated from other features of the apoptotic program, in Fas type I cells.
Alternative splicing of type II procollagen pre‐mRNA in chondrocytes is oppositely regulated by BMP‐2 and TGF‐β1
Authors: Valcourt Ulrich , Gouttenoire Jérôme , Aubert-Foucher Elisabeth , Herbage Daniel , Mallein-Gerin Frédéric
Published: May 2003

Type II collagen is the major protein of cartilage and is synthesized as a procollagen in two forms (IIA and IIB), generated by differential splicing of the gene primary transcript. Previous studies have indicated that only type IIB is expressed in differentiated chondrocytes. Here, we examined the effects of bone morphogenetic protein (BMP)‐2 and transforming growth factor (TGF)‐β1 on the expression of IIA and IIB forms expressed in de‐differentiated chondrocytes grown in monolayer. Our results demonstrate that BMP‐2 favors expression of type IIB whereas TGF‐β1 potentiates expression of type IIA induced by subculture. These observations reveal the specific capability of BMP‐2 to reverse the de‐differentiation state of chondrocytes.
Structural and functional analysis of a lycopene β‐monocyclase gene isolated from a unique marine bacterium that produces myxol
Authors: Teramoto Maki , Takaichi Shinichi , Inomata Yukie , Ikenaga Hiroshi , Misawa Norihiko
Published: May 2003

A gene coding for lycopene β‐monocyclase, which metabolizes lycopene (ψ,ψ‐carotene) to γ‐carotene (β,ψ‐carotene), was isolated for the first time from a unique marine bacterium strain P99‐3 that produces myxol (a γ‐carotene derivative). This lycopene β‐monocyclase gene (designated crtYm) was included in the gene cluster which contained carotenoid biosynthetic gene (crtI, crtB, crtZ, crtY, and crtA) homologs. CrtYm, the CrtY homolog, metabolized lycopene to γ‐carotene, which was confirmed by deletion/expression analysis of the crtYm and by subsequent analysis of the metabolites from lycopene based on the retention times on high‐performance liquid chromatography, UV–visible absorption spectra, and mass spectrometry.
Recognition of novel viral sequences that associate with the dynein light chain LC8 identified through a pepscan technique
Authors: Martı́nez-Moreno Mónica , Navarro-Lérida Inmaculada , Roncal Fernando , Albar Juan Pablo , Alonso Covadonga , Gavilanes Francisco , Rodrı́guez-Crespo Ignacio
Published: May 2003

Recent data from multiple laboratories indicate that upon infection, many different families of viruses hijack the dynein motor machinery and become transported in a retrograde manner towards the cell nucleus. In certain cases, one of the dynein light chains, LC8, is involved in this interaction. Using a library of overlapping dodecapeptides synthesized on a cellulose membrane (pepscan technique) we have analyzed the interaction of the dynein light chain LC8 with 17 polypeptides of viral origin. We demonstrate the strong binding of two herpesvirus polypeptides, the human adenovirus protease, vaccinia virus polymerase, human papillomavirus E4 protein, yam mosaic virus polyprotein, human respiratory syncytial virus attachment glycoprotein, human coxsackievirus capsid protein and the product of the AMV179 gene of an insect poxvirus to LC8. Our data corroborate the manipulation of the dynein macromolecular complex of the cell during viral infection and point towards the light chain LC8 as one of the most frequently used targets of virus manipulation.
Conducting the initiation of protein synthesis: the role of eIF4G
Authors: Prévôt Déborah , Darlix Jean‐Luc , Ohlmann Théophile
Published: May 2003

The eukaryotic initiation factor eIF4G is a large modular protein which serves as a docking site for initiation factors and proteins involved in RNA translation. Together with eIF4E and eIF4A, eIF4G constitutes the eIF4F complex which is a key component in promoting ribosome binding to the mRNA. Thus, the central role of eIF4G in initiation makes it a valid target for events aimed at modulating translation. Such events occur during viral infection by picornaviruses and lentiviruses and result in the hijack of the translational machinery through cleavage of eIF4G. Proteolysis of eIF4G is also mediated by caspases during the onset of apoptosis causing inhibition of protein synthesis. We will review the role of eIF4G and protein partners as well as the cellular and viral events that modulate eIF4G activity in the initiation of translation.
On two-dimensional hamiltonian transport equations with Llocp coefficients
Authors: Hauray M
Published: May 2003

We consider two-dimensional autonomous divergence free vector-fields in Lloc2. Under a condition on direction of the flow and on the set of critical points, we prove the existence and uniqueness of a stable a.e. flow and of renormalized solutions of the associated transport equation.

On considère ici des champs de vecteurs à divergence nulle et à coefficients dans Lloc2. Avec une condition locale sur la direction du champ de vecteur, on prouve l’existence et l’unicité d’un flot presque partout et des solutions renormalisées de l’équation de transport associée.
Association analysis of the insertion/deletion polymorphism in serotonin transporter gene in patients with affective disorder
Authors: Hauser Joanna , Leszczyńska Anna , Samochowiec Jerzy , Czerski Piotr M. , Ostapowicz Agata , Chlopocka Maria , Horodnicki Jan , Rybakowski Janusz K.
Published: May 2003

A polymorphism of serotonin transporter was studied in 226 patients with affective disorders (n = 132 for bipolar, n = 94 for unipolar affective disorder) and in 213 healthy subjects. Consensus diagnosis by at least two psychiatrists, according to the ICD-10 and DSM-IV criteria was made for each patient using SCID (Structured Clinical Interview for DSM-IV Axis I Disorders). A functional polymorphism in the promoter region of serotonin transporter gene, where 44 bp are either inserted (long allele) or deleted (short allele) was analysed. Genotype s/s was significantly more frequent in patients comparing to the control group (P = 0.011 for bipolar and P = 0.003 for unipolar affective disorder) - the most marked association was found in males with bipolar and unipolar illness. The allele frequencies also differ significantly between patients and controls (P = 0.003 for bipolar and P = 0.001 for unipolar affective disorder). The frequency of the low activity (short) allele was higher in patients than in controls (51.1% in bipolar, and 54.3 in unipolar vs 39.4% in controls). We suggest that the presence of allele s may increase the susceptibility to occurrence of affective disorder.
The role of limbic and cortical regions in schizophrenia: Focus on dopamine
Authors: Marchese G. , Pani L.
Published: May 2003

Dopamine is implicated in the pathogenesis of both the positive and the negative symptoms of schizophrenia. Clinical efficacy of antipsychotic drugs, without the production of side-effects, may be achieved by a dose–response separation of pharmacological function, regional (i.e., anatomical) selectivity of action, or by the selective targeting of neuroreceptors. The atypical antipsychotics have many different ways of acting on receptors in the brain, but they have in common a decreased likelihood of producing extrapyramidal side-effects. Patients respond well to them by showing improvements of both positive and negative symptoms. The preclinical profile of amisulpride shows specificity for D2/D3 dopamine receptors and selective activity in the limbic system. There is evidence that amisulpride is effective in treating both the negative and positive symptoms of schizophrenia, and that it has a low propensity to induce motor side-effects. Therefore, both positive and negative symptoms can be treated, without inducing these side-effects, by selectively targeting dopamine receptors.
From ‘communism’ to ‘democracy’ in Cambodia: a decade of transition and beyond
Authors: Roberts D.
Published: May 2003

This paper examines 10 years of political transition in Cambodia. It is particularly relevant because Cambodia has just passed through a third stage of transition in the form of national grass roots elections to dilute elite power. The scope of the paper covers the three elections in the period 1991–2002 and is located in Dankwart Rustow’s transition theory. I conclude that while basic elements of the theory hold true, qualifications are required in relation to the length of the ‘acceptance’ phase for the elites, and the extent to which, even after 10 years, habitually normalised democratic processes are still unreliable at best, and violent at worst.
Cytoskeletons in prokaryotes
Authors: Mayer F
Published: May 2003

Not only eukaryotes, but also prokaryotes possess a cytoskeleton. Tubulin‐related bacterial protein FtsZ, and actin‐related bacterial proteins MreB/Mbl have recently been described as constituents of bacterial cytoskeletons. Genes coding for MreB/Mbl could only be found in elongated bacteria, not in coccoid forms. It was speculated that constituents of today's eukaryotic cytoskeleton (tubulin, actin) may have evolved from prokaryotic precursor proteins closely related to today's bacterial proteins FtsZ and MreB/Mbl.

Prior to the description of proteins MreB/Mbl, evidence had been obtained for the existence of a shape‐preserving cytoskeleton ubiquitously present in all bacteria. In the meantime, structural studies allow to speculate on a possible role of bacterial elongation factor Tu (EF‐Tu) as a structural element in such a “cytoskeletal web”. EF‐Tu was long known to form fibrillar structures in vitro; now experimental data accumulate, pointing towards formation of intracellular protofilaments containing EF‐Tu, and networks thereof as well. In addition, results of these structural studies suggest a so far unknown mode of complex formation of EF‐Tu with active ribosomes: ribosomes/polysomes were seen to be attached to intracellular protofilaments. Implications for the understanding of EF‐Tu—ribosome interaction, and a role of such a kind of putative protofilaments as a general site of attachment for cellular functional macromolecules are discussed. The notion is discussed that an EF‐Tu‐containing cytoskeletal web might have been the “primary” or “basic” kind of prokaryotic cytoskeleton, already in existence prior to the “invention” of precursors of today's MreB.
Tacrolimus vs. cyclosporine A as primary immunosuppression in pediatric renal transplantation: A NAPRTCS study
Authors: Neu Alicia M. , (Martin) Ho P. L. , Fine Richard N. , Furth Susan L. , Fivush Barbara A.
Published: May 2003

Abstract:  Using the North American Renal Transplant Cooperative Study (NAPRTCS) database, we performed a retrospective cohort study of 986 pediatric renal transplant recipients (index transplant 1997–2000) who were treated either with Cyclosporine A (CSA), Mycophenolate Mofetil (MMF) and steroids (n = 766) or tacrolimus (TAC), MMF and steroids (n = 220) to examine potential difference in clinical outcomes between these two groups. In the first year post‐transplant, time to first rejection (29.1% vs. 29%, p = 0.840), risk for rejection [Adjusted Relative Risk (aRR) 1.01, 95% Confidence Interval (CI) 0.77, 1.323], graft survival (96.8% vs. 97.9%, p = 0.607) and risk for graft failure (aRR 0.988, 95% CI 0.64, 1.928) were not significantly different in TAC and CSA‐treated patients. At 2 yr post‐transplant, there was also no difference in risk for rejection (aRR 0.918, 95% CI 0.669, 1.259), graft survival (91.4% vs. 95.1%, p = 0.152) and risk for graft failure (aRR 0.702, 95% CI 0.461, 1.762) in the subset of 391 CSA‐treated patients and 77 TAC‐treated patients on whom 2 yr follow data were available in the database. TAC‐treated patients were significantly less likely to require antihypertensive medication at 1 yr [aRR 0.74 (95% CI 0.454, 0.637)] and 2 yr post‐transplant [aRR 0.67 (95% CI 0.56, 0.793)]. At 1 yr post‐transplant, TAC‐treated patients enjoyed a higher mean GFR as estimated by the Schwartz formula [89.1 mL/min/1.73 m2 (SE 2.64) vs. 78.6 mL/min/1.73 m2 (SE 1.07), p = 0.0003]. In addition, in the subset of patients with 2 yr of follow‐up, TAC patients had a higher mean GFR at both 1 yr [98.6 mL/min/1.73 m2 (SE 3.83) vs. 78.0 mL/min/1.73 m2 (SE 1.44), p = 0.0003] and 2 yr post‐transplant [96.7 mL/min/1.73 m2 (SE 3.33) vs. 73.2 mL/min/1.73 m2 (SE 1.48), p < 0.0001]. In summary, TAC and CSA, in combination with MMF and steroids, produce similar rejection rates and graft survival in pediatric renal transplant recipients. However, TAC is associated with improved graft function at 1 and 2 yr post‐transplant. Further analysis as more patient data are obtained will be necessary to determine if this difference in graft function persists and translates into improved graft survival.
Investigation of megakaryocyte apoptosis in children with acute and chronic idiopathic thrombocytopenic purpura
Authors: Uçar Canan , Ören Hale , I˙rken Gülersu , Ateş Halil , Atabay Berna , Türker Meral , Vergin Canan , Yaprak Işın
Published: May 2003

Abstract: Objective: Although the platelet destruction shows a primary role in the thrombocytopenia of idiopathic thrombocytopenic purpura (ITP), it has been demonstrated that impaired platelet production may also contribute to the severity of thrombocytopenia in ITP. The present study examined megakaryocyte apoptosis in bone marrow aspirates of children with acute and chronic ITP and investigated the role of megakaryocyte apoptosis in ITP pathophysiology.

Methods: Thirteen children diagnosed with acute ITP and eight children diagnosed with chronic ITP comprised the study group. Ten children, who were hospitalized for scoliosis operation but healthy otherwise, comprised the control group. In all children, megakaryocytes were isolated from the same amount of bone marrow aspirate samples using MACS CD61 MicroBeads (Miltenyl Biotec, Auburn, CA, USA). Megakaryocyte apoptosis was studied with transferase‐mediated d‐UTP‐bitin nick end‐labeling method.

Results: Isolated megakaryocyte counts did not differ significantly between acute ITP, chronic ITP and control groups. The percentage of apoptotic megakaryocytes did not differ significantly between acute ITP group and control group and between chronic ITP group and control group. The percentage of apoptotic megakaryocytes in patients with chronic ITP was significantly lower than the patients with acute ITP. There was no correlation between the percentage of apoptotic megakaryocytes and platelet counts of the cases.

Conclusions: Increased megakaryocytic apoptosis does not play a role in the pathogenesis of dysmegakaryopoiesis and impaired platelet production in children with ITP. Decreased megakaryocyte apoptosis in cases with chronic ITP may be due to suppression of megakaryocyte maturation, as the terminal phase of the megakaryocyte lifespan is characterized by the onset of apoptosis.
Sequence variation in the bovine and ovine PRNP genes
Authors: Hills D. , Schlaepfer J. , Comincini S. , MacLean I. , Dolf G. , Ferretti L. , Olsaker I. , Williams J. L.
Published: May 2003

A resequencing approach was adopted to identify sequence variants in the PRNP gene that may affect susceptibility or resistance to bovine spongiform encephalopathy. The entire PRNP gene (>21 kb) was sequenced from 26 chromosomes from a group of Holstein‐Friesian cows, as well as exon 3 of PRNP (>4 kb) from a further 24 chromosomes from six diverse breeds. We identified 51 variant sequences of which 42 were single nucleotide polymorphisms and nine were insertion/deletion (indel) events. The study was extended to exon 3 of the sheep PRNP gene where 23 sequence variants were observed, four of which were indels. The level of nucleotide diversity in the complete bovine PRNP gene was π = 0.00079, which is similar to that found at the bovine T‐cell receptor alpha delta joining region (π = 0.00077), but somewhat less than that observed for the bovine leptin (π = 0.00265). Sequence variation within exon 3 of PRNP in both cattle (π = 0.00102) and sheep (π = 0.00171) was greater than that for the complete PRNP gene, with sheep showing greater sequence variation in exon 3 than cattle. The level of sequence variation reported here is greater than previously thought for the bovine PRNP gene in cattle. This study highlights the contribution that recombination plays in increasing allelic diversity in this species.
Deletion of one of the duplicated Hsp70 genes causes hereditary myopathy of diaphragmatic muscles in Holstein‐Friesian cattle
Authors: Sugimoto M. , Furuoka H. , Sugimoto Y.
Published: May 2003

Heat‐shock protein 70 (Hsp70) is a major chaperone that folds protein and prevents aggregation. The Hsp70 family contains both constitutive and stress‐inducible forms. In humans, two of the inducible Hsp70 genes are located within the human major histocompatibility complex (MHC) on 6p21.3, as a duplicated locus, 12 kb apart from each other. We report that loss of one of the duplicated Hsp70 genes, the bovine homologue within the bovine MHC, is responsible for hereditary myopathy of diaphragmatic muscles (HMDM) in Holstein‐Friesian cattle. Although the remaining Hsp70 gene is intact, Hsp70 protein levels are dramatically decreased in affected cattle. In normal diaphragmatic muscle, Hsp70 binds several proteins involved in energy metabolism including glycogen phosphorylase (PYGM). Immunohistochemical staining indicated that PYGM accumulated in the HMDM‐specific core‐like structures in affected cattle. Misfolding of energy‐related proteins due to Hsp70 deficiency might lead to protein aggregation and muscle fibre degeneration.
Mean residence time of soil organic matter associated with kaolinite and smectite
Authors: Wattel‐ Koekkoek E. J. W. , Buurman P. , Van Der Plicht J. , Wattel E. , Van Breemen N.
Published: May 2003

To gain insight into the effect of clay mineralogy on the turnover of organic matter, we analysed the 14C activity of soil organic matter associated with clay in soils dominated by kaolinite and smectite in natural savanna systems in seven countries. Assuming that carbon inputs and outputs are in equilibrium in such soils, we took the 14C age as mean residence time of the organic matter. We corrected the 14C activity for the Suess effect, Bomb effect and difference between date of sampling and date of 14C measurement. Organic matter associated with kaolinite turned over fast (360 years on average). Organic matter associated with smectite turned over relatively slowly, with an average mean residence time for the whole clay‐size fraction of 1100 years. Multiple linear regression indicates that clay mineralogy is the main factor explaining differences in the mean residence time of the organic matter extracted.
Characteristics of dissolved organic matter and phenolic compounds in forest soils under silver birch (Betula pendula), Norway spruce (Picea abies) and Scots pine (Pinus sylvestris)
Authors: Suominen K. , Kitunen V. , Smolander A.
Published: May 2003

The aim was to characterize dissolved organic matter in soils under different tree species. Molecular size distribution and chemical composition of dissolved organic carbon and nitrogen were determined in water extracts from humus layers and mineral soils taken from silver birch (Betula pendula Roth.), Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.) stands. Concentrations of tannins and 15 phenolic acids in the humus layers were measured. Per unit of organic matter, the concentrations of dissolved organic C and N were larger in birch and spruce humus layers than in the pine humus layer. In the underlying mineral soil, the concentrations of dissolved organic C were similar at all sites, but the concentration of dissolved organic N was greater in spruce and pine soils than in birch soil. In all soils, the 10–100 kDa fraction was the most abundant molecular size group and hydrophobic acids the most abundant chemical group of dissolved organic C. In all humus layers, hydrophobic acids and hydrophilic bases were the major components of dissolved organic N. There were only minor differences in the concentrations of total tannins in the humus layers under different tree species. Small‐molecule tannins (about < 0.5 kDa) were most abundant in the birch humus, and large‐molecule tannins in the pine humus. Coniferous humus contained more ferulic and p‐coumaric acids than did the birch humus. The concentrations of 3,4 and 3,5‐dihydroxybenzoic acid, vanillic acid and 4‐hydroxybenzoic acid were similar in all soils.
Short‐term transformations of lead and cadmium compounds in soil after contamination
Authors: Bataillard P. , Cambier P. , Picot C.
Published: May 2003

The behaviour and fate of trace metals, in particular lead and cadmium, when they contaminate the soil as atmospheric fall‐out are not well understood. To improve our understanding, we incorporated pure compounds of lead and cadmium into samples taken from surface horizons of three chemically contrasting soils and monitored the changes in their speciation by analysing the soil solution. In most instances the concentrations of trace metals in solution were maximal during the first few days after mixing the contaminants with the soil, and depended strongly on soil type. The exception was when the contaminant was added as sulphide particles. The initial speciation of metals also influenced their solubility, following a decreasing order which did not depend on the soil type:

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Lead sulphide was progressively oxidized, but cadmium sulphide was hardly dissolved. When lead was added as sulphate, between 10 and 20% of lead particles dissolved, regardless of the soil type. For the other species, dissolution was enhanced at lower soil pH. Thermodynamic calculations with the WinHumic V program indicated that the solution was not saturated with respect to lead sulphate. We conclude that dissolution must be limited by the adsorption of inhibitors on reactive surfaces. The calculations also showed that precipitation of chloropyromorphite probably controls lead concentration in leachate from the acid organic soil. Finally, both soil type and initial speciation of contaminants control the behaviour of trace metals in soils for a time greater than a cropping season and must be considered for understanding their environmental impact.
Interaction of copper and zinc with allophane and organic matter in the B horizon of an Andosol
Authors: Latrille C. , Denaix L. , Lamy I.
Published: May 2003

Andosols developed on basaltic material are naturally rich in metals. Organic matter and allophane, the key colloids of these soils, have a strong affinity for trace metals, but are intimately mixed so that speciation of trace metal is difficult to determine. We used three complementary approaches, namely physical fractionation, chemical extraction and potentiometric measurement, to distinguish them. Physical particle‐size separations and chemical selective dissolution of allophanes and organic matter were combined to demonstrate relations between the occurrence of colloids and contents of Cu and Zn in an andic B horizon. About 22% of total soil Cu and 7% of total soil Zn were present in the < 5‐μm fraction, associated with organic or amorphous mineral constituents. To support this association further, the affinity of soil colloids for Cu and Zn in a mimicked system was demonstrated. An Al‐rich allophane was synthesized, and a portion of the organic matter was extracted from the clay fraction, and their reactivities towards Cu2+or Zn2+were studied by potentiometry. The two metallic cations displayed specific affinity towards allophane or soluble organic matter. Furthermore, the behaviour of copper and zinc in the ternary system, allophane + soluble organic matter + trace element, revealed a synergy in the surface complexation. The use of these three speciation approaches highlighted the linkage between metals and constituents, and showed how important the colloidal constituents are in the behaviour of Cu and Zn in Andosols.
Mineral surfaces and soil organic matter
Authors: Kaiser K. , Guggenberger G.
Published: May 2003

The organic carbon content of soil is positively related to the specific surface area (SSA), but large amounts of organic matter in soil result in reduced SSA as determined by applying the Brunauer–Emmett–Teller (BET) equation to the adsorption of N2. To elucidate some of the controlling mechanisms of this relation, we determined the SSA and the enthalpy of N2 adsorption of separates with a density > 1.6 g cm−3 from 196 mineral horizons of forest soils before and after removal of organic matter with NaOCl. Likewise, we investigated these characteristics before and after sorption of increasing amounts of organic matter to four mineral soil samples, oxides (amorphous Al(OH)3, gibbsite, ferrihydrite, goethite, haematite), and phyllosilicates (kaolinite, illite).

Sorption of organic matter reduced the SSA, depending on the amount sorbed and the type of mineral. The reduction in SSA decreased at larger organic matter loadings. The SSA of the mineral soils was positively related to the content of Fe oxyhydroxides and negatively related to the content of organic C. The strong reduction in SSA at small loadings was due primarily to the decrease in the micropores to which N2 was accessible. This suggests preferential sorption of organic matter at reactive sites in or at the mouths of micropores during the initial sorption and attachment to less reactive sites at increasing loadings. The exponential decrease of the heat of gas adsorption with the surface loading points also to a filling or clogging of micropores at early stages of organic matter accumulation. Desorption induced a small recovery of the total SSA but not of the micropore surface area.

Destruction of organic matter increased the SSA of all soil samples. The SSA of the uncovered mineral matrix related strongly to the amounts of Fe oxyhydroxides and the clay. Normalized to C removed, the increase in SSA was small in topsoils and illuvial horizons of Podzols rich in C and large for the subsoils containing little C. This suggests that micropores preferentially associate with organic matter, especially at small loadings. The coverage of the surface of the soil mineral matrix as calculated from the SSA before and after destruction of organic matter was correlated only with depth, and the relation appeared to be linear.

We conclude that mineralogy is the primary control of the relation between surface area and sorption of organic matter within same soil compartments (i.e. horizons). But at the scale of complete profiles, the surface accumulation and stabilization of organic matter is additionally determined by its input.
A comparison of randomized intervention analysis and two‐factor analysis of variance for analysis of angler effort in a floodplain river fishery
Authors: Cloutman D. G. , Jackson D. C.
Published: May 2003

Probability values were compared among randomized intervention analysis (RIA) and untransformed and loge‐transformed two‐factor analyses of variance (anova) to test effects of fish stocking and a public relations programme on angler effort. The data set consisted of a time series of angler vehicle counts at single control and impact locations in a before–after‐control‐impact (BACI) experimental design. A randomized complete block anova indicated that probability values from RIA and the untransformed and loge‐transformed two‐factor anova did not differ significantly (P = 0.345), and that they did not result in different conclusions concerning angler effort. Randomized intervention analysis is superior to two‐factor anova in not having to conform with assumptions of parametric statistics, and it tests for temporal autocorrelation. Two‐factor anova is superior to RIA in providing statistical inferences about possible differences in main effects, i.e. control and impact locations and pre‐ and post‐treatment periods, if the interaction term is non‐significant. To achieve the most comprehensive analysis, it is recommended that both RIA and two‐factor anova (whether untransformed or transformed) be performed during field experiments of angler effort when using a BACI design at single control and treatment locations.