bluuebunny/crossref_metadata_2025 huggingface dataset:
Putative precursors of endothelin have less vasoconstrictor activity in vitro but a potent pressor effect in vivo
Authors: Kashiwabara Tomoko , Inagaki Yoshimasa , Ohta Hideo , Iwamatsu Akihiro , Nomizu Motoyoshi , Morita Akihito , Nishikori Koji
Published: July 2002

Endothelin (ET‐21) induced a sustained contraction of rat thoracic aortae (EC50=2.65 × 10−10 M) in vitro, and caused a potent pressor effect in vivo after intravenous administration to rats. In contrast, the precursor deduced from porcine cDNA coding ET‐21 (pET‐39) had 100‐fold less contractile activity in vitro (EC50=3.26 × 10−8M), and so did the precursor from human cDNA (hET‐38) (EC50=1.48 × 10−8M). However, both pET‐39 and hET‐38 caused almost the same dose‐dependent pressor effects as ET‐21 in vivo. After intravenous bolus injection at 1 nmol/kg, ET‐21 caused an initial transient drop of the arterial pressure, and then induced a gradual pressor effect. On the other hand, hET‐38 caused only a gradual rise of the arterial pressure. There may be different mechanism(s) for ET‐21 and hET‐38 which induce changes in the arterial pressure in vivo.
A structure‐derived sequence pattern for the detection of type I copper binding domains in distantly related proteins
Authors: Ouzounis Christos , Sander Chris
Published: July 2002

A structure‐based approach to the definition of sequence patterns characteristic of protein domains is presented by example. The approach requires a multiple sequence alignment of a family (or set of related families) as well as at least one three‐dimensional structure. The pattern derived does not merely summarize the information in the known sequences but attempts to generalize the pattern specifications based on structural insight. In this example, the pattern‐driven database search identified correctly most of the known type I copper‐binding domains and detected the presence of a homologous domain in a previously unknown case (CopA protein). The significance of these results is discussed.
Novel structurally distinct family of leucocyte surface glycoproteins including CD9, CD37, CD53 and CD63
Authors: Hořejši Václav , Vlček Čestmir
Published: July 2002

Several of the recently described leucocyte surface (glyco)‐proteins with significant amino acid sequence similarity (human CD9, CD37, CD53, CD63, TAPA‐1, CO‐029 and R2 and several homologues of other species) are distinguished by the polypeptide chain apparently four times crossing the membrane. Although the biological role of none of these molecules is known, their structure, associations with other membrane components and the effects of specific monoclonal antibodies suggest that they may constitute a family of ion channels or other transport molecules.
Acute ammonia toxicity is mediated by the NMDA type of glutamate receptors
Authors: Marcaida Goizane , Felipo Vicente , Hermenegildo Carlos , Miñana Maria-Dolores , Grisolia Santiago
Published: July 2002

Previous experiments in our laboratory suggested that ammonium toxicity could be mediated by the NMDA type of glutamate receptors. To assess this hypothesis we tested if MK‐801, a specific antagonist of the NMDA receptor, is able to prevent ammonium toxicity. Mice and rats were injected i.p. with 12 and 7 mmol/kg of ammonium acetate, respectively, 73% of the mice and 70% of the rats died. However, when the animals were injected i.p. with 2 mg/kg of MK‐801, 15 min before ammonium injection, only 5% of the mice and 15% of the rats died. The remarkable protection afforded by MK‐801 indicates that ammonia toxicity is mediated by the NMDA receptor.
Multiple Ca2+ signaling pathways converge on CaM kinase in PC12 cells
Authors: MacNicol Melanie , Schulman Howard
Published: July 2002

The role of multifunctional Ca2+/calmodulin‐dependent protein kinase (CaM kinase) in mediating various Ca2+ signaling pathways was examined in PC12 cells. Conversion of the kinase to a Ca2+‐independent form was used to monitor which neurotransmitters activate the enzyme in situ. CaM kinase responds to Ca2+ influx elicited by ligand‐gated Ca2+ channels for ATP and acetylcholine. It also responds to Ca2+ mobilization ofIP3‐sensitive stores elicited by phospholipase C‐linked receptors for ATP and acetylcholine as well as by caffeine. CaM kinase mediates the actions of many neurotransmitters and Ca2+ signaling pathways.
In vitro interaction of fenretinide with plasma retinol‐binding protein and its functional consequences
Authors: Berni Rodolfo , Formelli Franca
Published: July 2002

The synthetic retinoid fenretinide (4‐HPR; N‐[4‐hydroxyphenyl] all‐trans‐retinamide) interacts with plasma apo‐retinol‐binding protein (RBP)to form a tight complex (λH
J = 0.2 μM) which does not exhibit binding affinity to transthyretin (TTR). Therefore, a substantial modification of the retinol hydroxyl group does not appear to affect the interaction with RBP but does drastically interfere with the protein—protein recognition. The remarkable early reduction in plasma retinol level induced by fenretinide administration may be associated with the high binding affinity of this retinoid to RBP and to its interference with the RBP—TTR complex formation.
A new intrinsic fluorescent probe for proteins Biosynthetic incorporation of 5‐hydroxytryptophan into oncomodulin
Authors: Hogue Christopher W.V. , Rasquinha Ingrid , Szabo Arthur G. , MacManus John P.
Published: July 2002

The tryptophan analog, 5‐hydroxytryptophan (5HW), has a significant absorbance between 310–320 nm, which allows it to act as an exclusive fluorescence probe in protein mixtures containing a large number of tryptophan residues. Here for the first time a method is reported for the biosynthetic incorporation of 5HW into an expressed protein, the Y57W mutant of the Ca2+ binding protein, oncomodulin. Fluorescence anisotropy and time‐resolved fluorescence decay measurements of the interaction between anti‐oncomodulin antibodies and the 5HW‐incorporated oncomodulin conveniently provide evidence of complex formation and epitope identification that could not be obtained with the natural amino acid. This report demonstrates the significant potential for the use or 5HW as an intrinsic probe in the study of structure and dynamics of protein—protein interactions.
The sequence of human caveolin reveals identity with VIP21, a component of transport vesicles
Authors: Glenney John R.
Published: July 2002

Caveolin is a protein present in membrane specializations termed caveolae where it may play a structural role. Previous studies on the cDNA sequence of chicken caveolin demonstrated that it is an integral membrane protein without significant homology to any known protein. The cDNA sequence of human lung caveolin is presented here. A striking sequence homology is observed with the chicken protein, as well as a very recently reported protein termed VIP21 [(1992) J. Cell Biol. 118, 1003–1014], a putative vesicle transport protein isolated from MDCK cells. Genomic Southern blots suggest that caveolin is present in a single copy, and Northern blots confirm that the caveolin mRNA is elevated in muscle.
The mitochondrial permeability transition pore may comprise VDAC molecules
Authors: Szabó Ildikó , Zoratti Mario
Published: July 2002

Electrophysiological records suggest that the pore responsible for the mitochondrial Ca2+‐dependent permeability transition (FTP), identified as the mitochondrial megachannel (MMC) observed in patch‐clamp experiments, may comprise two cooperating porin (VDAC) molecules. We have re‐investigated the voltage dependence of the megachannel, which favors the closed state(s) at negative (physiological) transmembrane potentials. This behavior confirms that MMC corresponds to the permeabilization pore. As detailed in the accompanying paper [(1993) FEBS Lett. 330, 206‐210] this voltage dependence resembles that of VDAC. Alpidem, a ligand of the mitochondrial benzodiazepine receptor, which reportedly comprises VDAC, the adenine nucleotide carrier and a third component, elicited currents from silent mitoplast patches, suggesting that the benzodiazepine receptor may be identical to the PTP/MMC.
Peptide aldehydes as inhibitors of HIV protease
Authors: Sarubbi Edoardo , Seneci Pier Fausto , Angelastro Michael R. , Peet Norton P. , Denaro Maurizio , Islam Khalid
Published: July 2002

We have recently shown that α‐MAPI, a peptidic aldehyde of microbial origin, inhibits the HIV protease with a potency comparable to pepstatin, having, differently from pepstatin, no activity on other aspartic proteases. In this study different peptide derivatives containing a C‐terminal aldehyde have been tested to assess the potential of this function for the inhibition of HIV protease. The results of our analysis correspond with the recently published subsite preferences of the viral enzyme, indicating that aldehydes bind to the active site of the HIV protease. Our data suggest that peptide aldehydes can act in their hydrated forms as transition state analogues with the most potent inhibitor having an IC50 of 0.9 μM.
Quantitative determination of oxidative base damage in DNA by stable isotope‐dilution mass spectrometry
Authors: Dizdaroglu Mirai
Published: July 2002

For understanding of the role of oxidative DNA damage in biological processes such as mutagenesis and carcinogenesis, it is essential to identify and quantify this type of DNA damage in cells. This can be achieved by gas chromatography/mass spectrometry. The present study describes the quantification of modified bases in DNA by isotope‐dilution mass spectrometry with the use of stable isotope‐labeled analogues as internal standards. A number of isotopically labeled DNA bases were synthesized. The mass spectra of their trimethylsilyl derivatives were recorded. Calibration plots were obtained for known quantities of modified bases and their isotope‐labeled analogues. Quantification of various modified DNA bases by isotope‐dilution mass spectrometry was demonstrated in isolated chromatin exposed to ionizing radiation. The results indicate that gas chromatography/stable isotope‐dilution mass spectrometry is an ideally suited technique for selective and sensitive quantification of modified bases in DNA.
Low pH crystal structure of glycosylated lignin peroxidase from Phanerochaete chrysosporium at 2.5 Å resolution
Authors: Piontek Klaus , Glumoff Tuomo , Winterhalter Kaspar
Published: July 2002

The heme‐containing glycoprotein lignin peroxidase (pI 4.15) has been crystallized at pH 4.0. The structure of the peroxidase from the orthorhombic crystals has been determined by multiple isomorphous replacement. The model comprises all 343 amino acids, one heme molecule, and three sugar residues. It has been refined to an R‐factor of 20.3%. The chain fold of residues 15 to 275 is in general similar to those of cytochrome c peroxidase. Despite binding of the heme to the same region and a similar arrangement of the proximal and distal histidine as in cytochrome c peroxidase a significantly larger distance of the iron ion to the proximal histidine is observed. Distinct electron density extending from Asn‐257 and at the distal side of the heme indicates ordered sugar residues in the crystal.
Proton‐translocating transhydrogenase and NAD‐ and NADP‐linked isocitrate dehydrogenases operate in a substrate cycle which contributes to fine regulation of the tricarboxylic acid cycle activity in mitochondria
Authors: Sazanov L.A. , Jackson J.B.
Published: July 2002

H+‐transhydrogenase (H+‐Thase) and NADP‐linked isocitrate dehydrogenase (NADP—ICDH) are very active in animal mitochondria but their physiological function is only poorly understood. This is especially so in the case of the heart and muscle, where there are no major consumers of NADPH. We propose here that H+‐Thase and NADP—ICDH have a combined function in the fine regulation of the activity of the tricarboxylic acid (TCA) cycle, providing enhanced sensitivy to changes in energy demand. This is achieved through cycling of substrates by NAD‐linked ICDH, NADP‐linked ICDH and H+‐Thase. It is proposed that NAD—ICDH operates in the forward direction of the TCA cycle, but NADP—ICDH is driven in reverse by elevated levels of NADPH resulting from the action of the transmembrane proton electrochemical potential gradient (Δp) on H+‐Thase. This has the effect of increasing the sensitivity to allosteric modifiers of NAD—ICDH (NADH, ADP, ATP, Ca2+ etc), potentially giving rise to large changes in the net flux from iso‐citrate to α‐ketoglutarate. Furthermore, changes in the level of Δp resulting from changes in the demand for ATP would, via H+‐Thase, shift the redox state of the NADP pool and this, in turn, would lead to a change in the rate of the reaction catalysed by NADP—ICDH and hence to an additional and complementary effect on the net metabolic flux from isocitrate to α‐ketoglutarate. Other consequences of this substrate cycle are, (i) the production of heat at the expense of Δp, which may contribute to thermoregulation in the animal, and (ii) an increased rate of dissipation of Δp (leak).
Singlet molecular oxygen production in the reaction of peroxynitrite with hydrogen peroxide
Authors: Di Mascio Paolo , Bechara Etelvino J.H. , Medeiros Marisa H.G. , Briviba Karlis , Sies Helmut
Published: July 2002

Peroxynitrite and hydrogen peroxide are mediators of cytotoxicity. This study shows that the peroxynitrite anion reacts with hydrogen peroxide to release oxygen accompanied by emission of chemiluminescence (CL). Direct characterization of this light emission attributes it to the transition of singlet molecular oxygen to the triplet ground state. Chemiluminescence was monitored: (i) by dimol light emission in the red spectral region (> 610 nm) using a red‐sensitive photomultiplier; and (ii) by monomol light emission in the infrared (1270 nm) with a liquid nitrogen‐cooled germanium diode. These properties of photoemission and the enhancing effect of deuterium oxide on CL intensity as well as the quenching effect of sodium azide are diagnostic of molecular oxygen in the excited singlet state. For comparison, singlet molecular oxygen arising from the thermolysis of the water‐soluble endoperoxide of 3,3′‐(1,4‐naphthylidene)dipropionate or from the hypochlorite/H2O2 system was also monitored. These novel observations identify a potential singlet oxygen‐dependent mechanism contributing to cytotoxicity mediated by peroxynitrite and hydrogen peroxide.
Human immunodeficiency virus uses tRNALys,3 as primer for reverse transcription in HeLa‐CD4+ cells
Authors: Das Atze T. , Koken Sabine E.C. , Oude Essink Belinda B. , van Wamel Jeroen L.B. , Berkhout Ben
Published: July 2002

Significant amounts of different tRNA molecules are present in retroviral particles, but one specific tRNA species functions as primer in reverse transcription. It is generally believed that the HIV‐1 virus uses the tRNALys,3 molecule as primer. This is based on sequence complementarity between the 3' end of tRNALys,3 and the primer‐binding site (PBS) on HIV‐1 genomic RNA. Recent biochemical analyses indicated that tRNALys,3 is indeed incorporated into viral particles. Interestingly, tRNALys,3 could not be detected in virions produced by HeLa‐CD4+ cells [(1992) Biochem. Biophys. Res. Commun. 185, 1105‐1115]. In order to test whether alternative tRNA molecules can function as primer in HIV replication, we performed a series of experiments based on the observation that tRNA primer sequences are inherited by the viral progeny. We cultured HIV‐1 for prolonged periods of time in HeLa‐CD4+ cells, but did not detect sequence changes in the PBS region. Furthermore, we found PBS‐mutants to be replication incompetent, again suggesting that HIV‐1 solely uses tRNALys,3 as primer. Most importantly, we obtained revertants of one such PBS‐mutant, which had restored a wild‐type PBS sequence. This tRNALys,3‐mediated repair demonstrates a general requirement for this primer in HIV‐1 reverse transcription.
Cloning of eggplant hypocotyl cDNAs encoding cytochromes P450 belonging to a novel family (CYP77)
Authors: Toguri Toshihiro , Tokugawa Klazuhisa
Published: July 2002

From eggplant hypocotyl tissues we have cloned two closely related cDNAs encoding cytochromes P450 (P450s) by PCR amplification using a primer designed based on the highly conserved sequence among the known eggplant P450s. One cDNA lacks the NH2‐terminal short sequence that is present in the other, full‐length cDNA. The two predicted protein sequences are 71% identical with each other and show less than 30% identity with any other known P450s. It is concluded that these P450s, which are termed CYP77A1 and ‐A2, belong to a hitherto unknown P450 family.
ADP‐ribosylation of Rho enhances adhesion of U937 cells to fibronectin via the α5β1 integrin receptor
Authors: Aepfelbacher Martin
Published: July 2002

To examine the role of Rho GTP binding proteins in the adhesion of monocytic cells to fibronectin we used the C3 exoenzyme of Clostridium botulinum which ADP‐ribosylates and inactivates Rho proteins in situ. Treatment of human monocytic U937 cells with C3 exoenzyme (10 μg/ml, 24 h) increased adhesion to fibronectin 2‐fold but had no effect on adhesion to collagen or human serum albumin. The increase in fibronectin adhesion was prevented by antibodies against the α5 and β1 integrin subunits, but surface expression of β1 and α5 was not altered. These results suggest that Rho proteins regulate the interaction of the monocyte α5β1 integrin receptor with fibronectin by post receptor mechanisms.
Species differences in the intracellular distribution of ciprofibroyl‐CoA hydrolase. Implications for peroxisome proliferation
Authors: Urrea Rodrigo , Bronfman Miguel
Published: July 2002

Peroxisomal proliferators (HPP), such as ciprofibrate and clofibric acid, are species‐specific drugs. Since HPP‐coenzyme A derivatives might be involved in their action, we studied the subcellular distribution of liver ciprofibroyl‐CoA hydrolase in rat and in two HPP‐unresponsive species, humans and guinea pig. Total activity was similar in the three species and was not induced by clofibric acid treatment. In guinea pig, as in humans, the enzyme is localized in the mitochondrial and soluble fractions and no changes are observed after drug treatment. In the rat, the enzyme has a microsomal localization, but upon clofibric acid treatment it changes to a mitochondrial and soluble distribution, as in unresponsive species. These results raise the possibility that drug‐induced hydrolases in rats might be normally expressed in humans and guinea pigs.
Vaginal hysterectomy following previous cesarean section
Authors: Sheth S.S. , Malpani A.N.
Published: July 2002

Objective: To determine whether hysterectomy by the vaginal route is safe and feasible in patients with previous cesarean section. Methods: A retrospective study of the records of private and public hospital patients who underwent vaginal hysterectomy performed by the senior author. Two hundred twenty patients who had had previous cesarean sections were compared with a control group of 200 patients who had not had previous pelvic surgery, with special reference to operative difficulties, intraoperative complications, surgical time and length of hospital stay. Results: It was possible to perform vaginal hysterectomy safely in patients with previous cesarean sections. Three of 200 (1.5%) patients had inadvertent intraoperative urological trauma because of dense adhesions. Conclusions: The vaginal route is the route of choice for performing a hysterectomy in patients with previous cesarean section.
Decreased heart rate variability parameters in amitriptyline treated depressed patients: biological and clinical significance
Authors: Rechlin T , Claus D , Weis M , Kaschka WP
Published: July 2002

One hundred-four depressed patients treated with amitriptyline (mean dosage: 163 mg/d; mean plasma level: 239 ng/ml) and 52 normal control subjects matched for age and sex underwent a standardized cardiovascular test battery (various autonomic cardiac parameters, which are largely independent from heart rate, namely the coefficients of variation (CV) while resting and during deep respiration, a spectral analysis of heart rate, the Valsalva ratio, and a posture index were determined). The tests included the determination of time- and frequency-derived measurements of heart rate variability (HRV), which is rather independent from heart rate. As compared to the controls the patients showed a significant plasma concentration-dependent decrease of R-R variation in the electrocardiogram (p < 0.0001), while their heart rate was significantly elevated (p < 0.0001). The markedly reduced parameters of sinus arrhythmia in amitriptyline treated patients are suggested to be mainly due to the anticholinergic effect of this drug, although it can not be excluded that the affective disorder itself might be associated with low heart rate variability. The results indicate that autonomic heart rate parameters are a valuable tool for the detection of tricyclic antidepressant (TCA) intake in unconscious patients, especially in intensive care and emergency wards.
Ethical issues in European psychiatry
Authors: Neeleman J , van Os J
Published: July 2002

European psychiatrists and psychiatric service planners are confronting new ethical dilemmas as a direct or indirect result of European integration. These dilemmas present themselves at a variety of levels, ranging from the individual doctor-patient relationship to national and international legislations. We review some of the areas in which ethical questions may arise as a result of increasing European unity. Some of the issues may seem minor but are likely to have some impact on any psychiatrist exposed to transcultural practice in the European Union. Other examples have been selected not because they are common but because of their massive ethical ramifications. Attempts, by psychiatrists, to address these issues pro-actively are few and far apart.
WHO Initiative of Support to People Disabled by Mental Illness: some issues and concepts related to rehabilitation
Authors: Bertolote JM , Sartorius N
Published: July 2002

This paper describes some of the World Health Organization's (WHO.) activities related to psychosocial rehabilitation highlighting its Initiative of Support to People Disabled by Mental Illness. Critical issues related to consumer empowerment and the role consumers can play in psychosocial rehabilitation are discussed. Consensus and disagreements between medical and lay views about concepts relating to mental disorders and rehabilitation are also discussed. WHO future work in this area is indicated.
Fugu: a compact vertebrate reference genome
Authors: Venkatesh Byrappa , Gilligan Patrick , Brenner Sydney
Published: July 2002

At 400 Mb, the Japanese pufferfish, Fugu rubripes, has the smallest vertebrate genome but has a similar gene repertoire to other vertebrates. Its genes are densely packed with short intergenic and intronic sequences devoid of repetitive elements. It likely has a mutational bias towards DNA elimination and is probably close to a ‘minimal’ vertebrate genome. As such it is a useful reference genome for gene discovery and gene validation in other vertebrates. Its usefulness in the discovery of conserved regulatory elements has already been demonstrated. The Fugu genome sequence is a good complement to genetic studies in other vertebrates.
The respiratory complex I of bacteria, archaea and eukarya and its module common with membrane‐bound multisubunit hydrogenases
Authors: Friedrich Thorsten , Scheide Dierk
Published: July 2002

The proton‐pumping NADH:ubiquinone oxidoreductase, also called complex I, is the first of the respiratory complexes providing the proton motive force which is essential for energy consuming processes like the synthesis of ATP. Homologues of this complex exist in bacteria, archaea, in mitochondria of eukaryotes and in chloroplasts of plants. The bacterial and mitochondrial complexes function as NADH dehydrogenase, while the archaeal complex works as F420H2 dehydrogenase. The electron donor of the cyanobacterial and plastidal complex is not yet known. Despite the different electron input sites, 11 polypeptides constitute the structural framework for proton translocation and quinone binding in the complex of all three domains of life. Six of them are also present in a family of membrane‐bound multisubunit [NiFe] hydrogenases. It is discussed that they build a module for electron transfer coupled to proton translocation.
Eicosapentaenoic acid (EPA) induces Ca2+‐independent activation and translocation of endothelial nitric oxide synthase and endothelium‐dependent vasorelaxation
Authors: Omura Masato , Kobayashi Sei , Mizukami Yoichi , Mogami Kimiko , Todoroki-Ikeda Natsuko , Miyake Teruki , Matsuzaki Masunori
Published: July 2002

Eicosapentaenoic acid (EPA), but not its metabolites (docosapentaenoic acid and docosahexaenoic acid), stimulated nitric oxide (NO) production in endothelial cells in situ and induced endothelium‐dependent relaxation of bovine coronary arteries precontracted with U46619. EPA induced a greater production of NO, but a much smaller and more transient elevation of intracellular Ca2+ concentration ([Ca2+]i), than did a Ca2+ ionophore (ionomycin). EPA stimulated NO production even in endothelial cells in situ loaded with a cytosolic Ca2+ chelator 1,2‐bis‐o‐aminophenoxythamine‐N′,N′,N′‐tetraacetic acid, which abolished the [Ca2+]i elevations induced by ATP and EPA. The EPA‐induced vasorelaxation was inhibited by N

ω
‐nitro‐L‐arginine methyl ester. Immunostaining analysis of endothelial NO synthase (eNOS) and caveolin‐1 in cultured endothelial cells revealed eNOS to be colocalized with caveolin in the cell membrane at a resting state, while EPA stimulated the translocation of eNOS to the cytosol and its dissociation from caveolin, to an extent comparable to that of the eNOS translocation induced by a [Ca2+]i‐elevating agonist (10 μM bradykinin). Thus, EPA induces Ca2+‐independent activation and translocation of eNOS and endothelium‐dependent vasorelaxation.
Mutants of Discosoma red fluorescent protein with a GFP‐like chromophore
Authors: Wiehler Jens , von Hummel Julia , Steipe Boris
Published: July 2002

The green fluorescent protein (GFP)‐homologous red fluorescent protein (RFP) from Discosoma (drFP583) which emits bright red fluorescence peaking at 583 nm is an interesting novel genetic marker. We show here that RFP maturation involves a GFP‐like fluorophore which can be stabilized by point mutations selected from a randomly mutated expression library. By homology modeling, these point mutations cluster near the imidazolidinone ring of the chromophore. Exciting the GFP‐like absorption band in the mutant proteins produces both green and red fluorescence. Upon unfolding and heating, the absorption spectrum of the RFP chromophore slowly becomes similar to that of the GFP chromophore. This can be interpreted as a covalent modification of the GFP chromophore in RFP that appears to occur in the final maturation step.
Glucose‐dependent and ‐independent signalling functions of the yeast glucose sensor Snf3
Authors: Dlugai Silke , Hippler Silke , Wieczorke Roman , Boles Eckhard
Published: July 2002

The yeast Snf3 protein has been described to function as a sensor for low concentrations of extracellular glucose. We have found that Snf3 is able to transduce a signal in the complete absence of extracellular glucose. High basal activity of the HXT7 promoter during growth on ethanol required Snf3 as well as other components of the signalling pathway activated by Snf3. Moreover, the C‐terminal domain of Snf3 was sufficient to complement the role of Snf3 in this regulation. As the C‐terminal tail of Snf3 interacted with other components at the plasma membrane independent of the carbon source, our data suggest that Snf3 is involved in signalling complexes which can be activated by other signals than extracellular glucose.
Escherichia coli inorganic pyrophosphatase : site‐directed mutagenesis of the metal binding sites
Authors: Avaeva Svetlana , Ignatov Pavel , Kurilova Svetlana , Nazarova Tatjana , Rodina Elena , Vorobyeva Natalja , Oganessyan Vaheh , Harutyunyan Emil
Published: July 2002

Aspartic acids 65, 67, 70, 97 and 102 in the inorganic pyrophosphatase of Escherichia coli, identified as evolutionarily conserved residues of the active site, have been replaced by asparagine. Each mutation was found to decrease the κ
app value by approx. 2–3 orders of magnitude. At the same time, the K
m values changed only slightly. Only minor changes take place in the pK values of the residues essential for both substrate binding and catalysis. All mutant variants have practically the same affinity to Mg2+ as the wild‐type pyrophosphatase.
Reactive oxygen species induce apoptosis of vascular smooth muscle cell
Authors: Li Pei-Feng , Dietz Rainer , von Harsdorf Rüdiger
Published: July 2002

© 1997 Federation of European Biochemical Societies.
Ubiquitin is physiologically induced by interferons in luminal epithelium of porcine uterine endometrium in early pregnancy: global RT‐PCR cDNA in place of RNA for differential display screening1
Authors: Chwetzoff Serge , d'Andrea Sabine
Published: July 2002

Early in the course of pregnancy, at the preimplantation stage, the pig embryo is likely to exert a paracrine effect on the tissue intended to receive it, via the secretion of interferons. Our observations show that trophoblastic interferons induce an increase of some mRNAs in the epithelial cells of the gilt endometrium, which would illustrate this phenomenon. The increase of four mRNAs, whose corresponding cDNAs are dD1, dD2, dD3 and dD4, has been examined in this study. The method used is similar to Northern blot analysis except that mRNAs in the blot are replaced by cDNAs produced from total cellular poly(A)+ mRNAs by global
everse‐
ranscription
olymerase
hain
eaction (RT‐PCR). Northern blot hybridization requires a considerable quantity of starting material – which we estimate in this study to be several million porcine endometrium cells – whereas the RT‐PCR‐based method gives comparable results starting with only a few cells – about 200. Using this method, the differential nature of dD1, dD2, dD3 and dD4 was shown. dD2 and dD3 correspond to genes already identified as interferon‐induced: the β2‐microglobulin and
inkel‐Biskis‐Reilly murine sarcoma virus‐
ssociated
biquitously secreted protein (FAU). dD1 corresponds to a still unidentified gene. dD4 encodes for the porcine UbA52 ubiquitin. Up to now, the increase in ubiquitin mRNA as a result of interferon effect has not been reported and is discussed in view of recent publications.
Contribution of β‐lactamase production to the resistance of mycobacteria to β‐lactam antibiotics
Authors: Quinting Birgit , Reyrat Jean-Marc , Monnaie Didier , Amicosante Gianfranco , Pelicic Vladimir , Gicquel Brigitte , Frère Jean-Marie , Galleni Moreno
Published: July 2002

Mycobacterium fallax (M. fallax) is naturally sensitive to many β‐lactam antibiotics (MIC<2 μg/ml) and devoid of β‐lactamase activity. In this paper, we show that the production of the β‐lactamase of Mycobacterium fortuitum by M. fallax significantly increased the MIC values for good substrates of the enzyme, whereas the potency of poor substrates or transient inactivators was not modified. The rates of diffusion of β‐lactams through the mycolic acid layer were low, but for all studied compounds the half‐equilibration times were such that they would only marginally affect the MIC values in the absence of β‐lactamase production. These results emphasize the importance of enzymatic degradation as a major factor in the resistance of mycobacteria to penicillins.
Substrate specificity of α‐1,6‐mannosyltransferase that initiates N‐linked mannose outer chain elongation in Saccharomyces cerevisiae
Authors: Nakayama Ken-ichi , Nakanishi-Shindo Yoko , Tanaka Atsushi , Haga-Toda Yoshiko , Jigami Yoshifumi
Published: July 2002

Yeast Saccharomyces cerevisiae OCH1 gene encodes the mannosyltransferase that is essential for the outer chain elongation of N‐linked oligosaccharides. Mannosyltransferase activity of OCH1 gene product (Och1p) was measured on HPLC by using pyridylaminated Man8GlcNAc2 (Man8GlcNAc2‐PA) as an acceptor and the reaction product was observed at the retention time corresponding to Man9GlcNAc2‐PA. 1H‐NMR and fast atom bombardment mass spectrometry (FAB‐MS) fragmentation analysis of Man9GlcNAc2‐PA showed that the additional mannose was attached with an α‐1,6 linkage at the site where mannose outer chain elongation initiates. Substrate specificity of Och1p was investigated by using various high mannose‐type oligosaccharides as acceptors. Man8GlcNAc2 was the best acceptor for Och1p. The loss of one or two α‐1,2‐mannoses from Man8GlcNAc2 reduced the mannosyltransferase activity and the Man5GlcNAc2 completely lacking α‐1,2‐mannose residues did not serve as an acceptor. Man8GlcNAcOH that involves an open sugar ring by reduction of reducing terminal GlcNAc residue did not serve as an acceptor for Och1p. The loss of three mannoses at the α‐1,6‐branch also reduced the Och1p activity. These results suggest that Och1p is an initiation specific α‐1,6‐mannosyltransferase that requires the intact structure of Man8GlcNAc for efficient mannose outer chain initiation.
Stimulation of prostaglandin G/H synthase‐2 expression by arachidonic acid monoxygenase product, 14,15‐epoxyeicosatrienoic acid
Authors: Peri Krishna G. , Varma Daya R. , Chemtob Sylvain
Published: July 2002

The relationship between arachidonic acid (AA) mobilization and transcription of immediate‐early genes, particularly of prostaglandin G/H synthase‐2 (PGHS‐2), in intestinal crypt epithelial cells was analyzed. PGHS‐2 mRNA and protein synthesis were stimulated by its own substrate, AA; actinomycin D, a transcription inhibitor, prevented the AA‐induced increase in PGHS‐2 mRNA. Eicosatetraynoic acid, an inhibitor of AA utilization, significantly reduced PGHS‐2 mRNA synthesis elicited by AA. Inhibitors of cytochrome P450 monoxygenases, ketoconazole and miconazole, also prevented PGHS‐2 mRNA synthesis in a dose‐dependent manner. Phenyl chalcone oxide, an epoxide hydrolase inhibitor, potentiated AA‐induced PGHS‐2 mRNA synthesis. Of the four regioisomers of arachidonic acid epoxides, only 14,15‐epoxyeicosatrienoic acid elicited the expression of PGHS‐2 in intestinal crypt epithelial cells. This is the first direct evidence of stimulation of an immediate‐early gene product, specifically PGHS‐2, by an AA epoxygenase metabolite, 14,15‐epoxyeicosatrienoic acid, as well as of a heterologous regulation of PGHS‐2 synthesis by these monoxygenase products.
Sequences of rDNA internal transcribed spacers from the chloroplast DNA of 26 bryophytes: properties and phylogenetic utility
Authors: Samigullin Tagir H , Valiejo-Roman Karmen M , Troitsky Aleksey V , Bobrova Vera K , Filin Vladimir R , Martin William , Antonov Andrey S
Published: July 2002

We determined the sequence of the region of the chloroplast DNA inverted repeat spanning from the 3′‐terminus of the 23S rRNA gene to the 5′‐terminus of the tRNAArg(ACG) gene (about 700 bp) from 25 bryophytes and from the charophycean alga Chara australis. Phylogenetic analysis of these sequences using the neighbor‐joining method suggests an early dichotomy of bryophytes and their paraphyly relative to the tracheophyte lineage. A monophyly of liverworts (Marchantiidae plus Jungermanniidae), a deep divergence of Metzgeriales among Jungermanniidae and a close affinity of the two subclasses of mosses, Sphagnidae and Andreaeidae, are evident. The branching pattern observed is consistent with the phylogenetic distribution of several prominent indels observed in the alignment.
Thrombopoietin stimulates VEGF release from c‐Mpl‐expressing cell lines and haematopoietic progenitors
Authors: Bobik Renata , Hong Ying , Breier Georg , Martin John F , Erusalimsky Jorge D
Published: July 2002

Vascular endothelial growth factor (VEGF) production was analysed in megakaryocytic cell lines and CD34+ haematopoietic progenitors following treatment with thrombopoietin (TPO). In CMK cells TPO caused a time‐ and dose‐dependent increase in the levels of VEGF released into the medium. A similar effect was observed in UT‐7/mpl cells transfected with the TPO receptor c‐Mpl, but not in parental UT‐7 cells. In CD34+ haematopoietic progenitor cell cultures TPO stimulated VEGF mRNA expression and VEGF protein release. Production of VEGF in CD34+ cultures increased with TPO‐induced megakaryocytic differentiation, but not with erythroid or myelomonocytic differentiation induced respectively by erythropoietin and granulocyte‐macrophage colony‐stimulating factor. These results demonstrate that TPO stimulates VEGF release in c‐Mpl‐expressing cells and suggest that this process is an integral feature of the megakaryocytic differentiation programme.
Kainate receptors: an interplay between excitatory and inhibitory synapses
Authors: Lerma Juan
Published: July 2002

The potent excitatory amino acid glutamate mediates its excitatory effects through a great variety of specific ionotropic receptors, including NMDA, AMPA and kainate receptors. Despite the identification, isolation and cloning of several subunits of the kainate receptor, this receptor has been rather elusive and its function remains enigmatic. Recent results indicate that kainate receptors can be reached by synaptically released glutamate and that their activation downregulates GABAergic inhibition by modulating the reliability of GABA synapses. Thus, kainate receptors may have a role in the etiology of epilepsy and could become a target for antiepileptic drugs.
Interaction between class B β‐lactamases and suicide substrates of active‐site serine β‐lactamases
Authors: Prosperi-Meys Christelle , Llabres Gabriel , de Seny Dominique , Paul Soto Raquel , Hernandez Valladares Maria , Laraki Netza , Frere Jean-Marie , Galleni Moreno
Published: July 2002

The most widely used inactivators of active‐site serine β‐lactamases behave as substrates of four class B metallo‐β‐lactamases, but the efficiency of the catalytic process can vary by several orders of magnitude. A comparison of the kinetic parameters for the α and β isomers of 6‐iodopenicillanic acid shows that there is no general preference for the α isomer and that the efficient hydrolysis of imipenem by these enzymes must rest on other factors.
Interaction of tissue transglutaminase with nuclear transport protein importin‐α3
Authors: Peng Xiaojun , Zhang Yonghui , Zhang Haifan , Graner Scott , Williams James F. , Levitt Mark L. , Lokshin Anna
Published: July 2002

Tissue transglutaminase is a multifunctional enzyme which has been involved in the regulation of cell growth, differentiation, and apoptosis. Recently, nuclear localization of tTG has been reported indicating the potential of active nuclear transport. In this study we use the yeast two‐hybrid assay and co‐immunoprecipitation to show that tTG interacts with the nuclear transport protein importin‐α3. Using electron microscopy we demonstrate that nuclear expression of tTG in a non‐small cell lung cancer cell line is induced by retinoic acid (RA). These data suggest that importin‐α3 could mediate active nuclear transport of tTG which may be important for the regulation of critical cellular processes.
Astrocytes enhance radical defence in capillary endothelial cells constituting the blood‐brain barrier
Authors: Schroeter Matthias L. , Mertsch Katharina , Giese Helga , Müller Sebastian , Sporbert Anje , Hickel Barbara , Blasig Ingolf E.
Published: July 2002

Astrocytes (AC) induce blood‐brain barrier (BBB) properties in brain endothelial cells (EC). As antioxidative activity (AOA) is assumed to be a BBB characteristic, we tested whether AC improve AOA of EC. Monocultivated AC showed higher AOA [manganese superoxide dismutase (SOD), catalase (Cat), glutathione peroxidase (GPx)] than EC. Cocultivation elevated AOA in EC (MnSOD, CuZnSOD, Cat, GPx), and AC (MnSOD, CuZnSOD, GPx). Hypoxia increased radical‐induced membrane lipid peroxidation in monocultivated, but not in cocultivated EC. Thus, EC/AC cocultivation intensifies AOA in both cell types, protects the EC, and therefore, the BBB against oxidative stress. The high AOA is regarded as an essential property of the BBB, which is induced by AC.
Mildly oxidised low density lipoprotein induces platelet shape change via Rho‐kinase‐dependent phosphorylation of myosin light chain and moesin
Authors: Retzer Michaela , Siess Wolfgang , Essler Markus
Published: July 2002

Oxidised low density lipoprotein (LDL) plays an important role in the pathogenesis of atherosclerosis. Here we demonstrate that mildly oxidised (mox) LDL engages the GTPase Rho and its effector molecule p160 Rho‐kinase to induce phosphorylation of myosin light chain and of moesin leading to platelet shape change. Pretreatment of platelets with the selective Rho inhibitor C3‐transferase from Clostridium botulinum or with the Rho‐kinase inhibitor Y‐27632 blocked mox‐LDL‐induced myosin light chain phosphorylation, moesin phosphorylation and shape change. Mox‐LDL did not induce an increase in cytosolic Ca2+ during shape change. We propose that Rho/Rho‐kinase inhibition could be a strategy for prevention of the pathologic platelet activation during atherogenesis.
Ephrin‐B2 is a candidate ligand for the Eph receptor, EphB6
Authors: Munthe Else , Rian Edith , Holien Toril , Rasmussen Anne-Marie , Levy Finn Olav , Aasheim Hans-Christian
Published: July 2002

No ligand has hitherto been designated for the Eph receptor tyrosine kinase family member, EphB6. Here, expression of an EphB6 ligand in the pro‐B leukemic cell line, Reh, is demonstrated by binding of soluble EphB6‐Fc fusion protein to the Reh cells. The ligand belongs to the subgroup of membrane spanning ligands, as suggested by the fact that phosphatidylinositol‐specific phospholipase C treatment did not abrogate binding of EphB6‐Fc. Two transmembrane Eph receptor ligands, ephrin‐B1 and ephrin‐B2, were identified in Reh cells. Analysis of EphB6‐Fc fusion protein binding to ephrin‐B1 or ephrin‐B2 transfected COS cells revealed a high‐affinity saturable binding between EphB6‐Fc and ephrin‐B2, but not with ephrin‐B1. In mice, EphB6 has previously been shown to be expressed in thymus. Here, we show expression of EphB6 in human thymus, as well as the expression of ephrin‐B2 in both human and mouse thymus. We conclude that ephrin‐B2 may be a physiological ligand for the EphB6 receptor.
Citalopram in mentally retarded patients with depression: a long-term clinical investigation
Authors: Verhoeven W.M.A. , Veendrik-Meekes M.J. , Jacobs G.A.J. , van den Berg Y.W.M.M. , Tuinier S.
Published: July 2002

The effect of citalopram was investigated in 20 mentally retarded patients suffering from a depressive disorder characterized by alterations in the domains of affectivity, motivation, motor activity and vital signs. The study followed a baseline-controlled open design. Citalopram was started in a daily dosage of 20 mg that was kept unchanged for 6 weeks. Thereafter dosage was adjusted to maximally 60 mg per day. Treatment effects were assessed according to the Clinical Global Improvement Scale (CGIS) after at least 6 months.

In 12 of the 20 patients a moderate to marked improvement in all domains was observed upon treatment with 20–40 mg citalopram daily. Treatment for one year in the effective dose prevented recurrence of depressive symptomatology. Concomitant use of sedative anticonvulsants reduced responsiveness to treatment. No interactions were observed.

It is concluded that citalopram is a well-tolerated, safe and effective antidepressant in mentally retarded subjects with depressive disorders.
Can better recognition and treatment of depression reduce suicide rates? A brief review
Authors: Rihmer Z.
Published: July 2002

Depression, the major cause of suicide, is prevalent but an under-detected, underdiagnosed and, under-treated illness and it is particularly true for depressed suicide victims. However, several studies consistently show that successful treatment of depression not only relieves depressive symptoms, but also decreases and makes suicidality vanish. If the rate of treated depressions in the population increases gradually, at a given point it will appear in the decline of the suicide rates. Although absolute evidence is lacking at present, recent reports from some European countries strongly suggest that increasing utilisation of antidepressants is one of the most important contributing factors in the decrease in suicide rates.
Detection and Treatment of Mental Disorders in General Health Care
Authors: Huyse FJ , Herzog T , Lobo A , Lyons JS , Slaets JPJ , Fink P , Stiefel F , de Jonge P
Published: July 2002

Mental health service delivery in the general health care sector is restricted with regard to understanding the magnitude and impact of mental illness in the medically ill (co-morbidity), as well as the significance of current mental health service delivery. A new model in development in the framework of a Biomed2 grant is presented. It consists of case-finding through complexity of hospital care prediction (COMPRI) followed by an integral health service needs assessment (INTERMED). It might serve to develop a more structural relation with the general health care sector for the management of mentally co-morbid high utilizing patients.
Post-stroke depression: Diagnosis and incidence
Authors: Andersen G
Published: July 2002

Diagnosis of post-stroke depression (PSD) is extremely difficult due to concomitant focal cognitive disturbances or generalized intellectual impairment, and, in some cases, dissociation of mood and affective behavior. The diagnosis has been standardized on the basis of psychiatric criteria in the Diagnostic and Statistical Manual (DSM)-III, an approach that has been criticized for taking into account non-specific stroke-related somatic symptoms. Yet evaluation of the PSD diagnosis by comparing the severity of depressive symptoms in stroke to an age-matched population sample and by conducting a controlled antidepressant treatment study in unselected PSD patients has failed to disclose any evidence that non-specific symptoms influence the diagnosis of PSD. The prognosis, however, of early vs late diagnosed PSD and the response to treatment of early vs late diagnosed PSD differ, indicating that PSD diagnosed according to DSM-III criteria covers a heterogeneous group of etiologically different conditions.