bluuebunny/crossref_metadata_2025 huggingface dataset:
Phenotypic selection in a natural population of Impatiens pallida Nutt. (Balsaminaceae)
Authors: Gross J. , Husband B. C. , Stewart S. C.
Published: December 2004

In the annual plant Impatiens pallida, individuals exhibit a floral heteromorphism consisting of autogamously selfing, cleistogamous (CL) flowers and partially outcrossing, chasmogamous (CH) flowers. As part of an investigation into natural selection and mating system evolution in I. pallida, we measured the magnitude and direction of phenotypic selection on nine life history characters (two traits measured on three dates, one measured on two dates and one measured once). Three of these characters were positively correlated with the ratio of CH/CL flowers produced per plant, which is an important determinant of the mating system. Values for the nine characters and three different measures of fitness (viability, fecundity, lifetime) were estimated for 500 plants in five locations over a single growing season. Based on lifetime fitness, linear selection differentials were significant for all nine characters, indicating a selective advantage to tall, leafy, highly branched plants that flowered early. However, only two of these characters had a direct effect on fitness. Selection was significant on all nine characters when based on fecundity as well as lifetime fitness; however, only three of five characters examined had significant selection based on viability fitness. For all fitness components, the frequency of significant linear and nonlinear selection coefficients was comparable (23% vs 17% of all cases, respectively), but nonlinear coefficients were generally larger. Finally, the magnitude and direction of direct linear selection was heterogeneous among locations, for all characters and all fitness components. Collectively these results suggest that selection is strong, favouring large size, high allocation to reproduction and high CH/CL flower ratios. However, any directional evolutionary changes in vegetative or reproductive characters may be constrained by strong non‐linear and correlational selection.
Evolutionary genetics and ecology of sperm‐dependent parthenogenesis
Authors: Beukeboom L. W. , Vrijenhoek R. C.
Published: December 2004

Sperm‐dependent (or pseudogamous) forms of parthenogenetic reproduction occur in a wide variety of animals. Inheritance is typically clonal and matroclinous (of female descent), but sperm are needed to initiate normal development. As opposed to true parthenogenesis (i.e., sperm‐independent reproduction), pseudogamous parthenogenetic lineages must coexist with a ‘sperm donor’— e.g., males from a conspecific sexual lineage, conspecific hermaphrodites, or males from a closely related sexual species. Such sperm donors do not contribute genetically to the next generation. The parasitic nature of sperm‐dependent parthenogenesis raises numerous ecological and evolutionary questions. How do they arise? What factors help stabilize coexistence between the pseudogamous parthenogens and their sperm donors (i.e., ‘sexual hosts’)? Why do males waste sperm on the asexual females? Why does true parthenogenesis not evolve in pseudogamous lineages and free them from their dependency on sperm donors? Does pseudogamous parthenogenesis provide compensatory benefits that outweigh the constraints of sperm‐dependence? Herein, we consider some genetic, ecological, and geographical consequences of sperm‐dependent parthenogenesis in animals.
Essential roles of lipoyl domains in the activated function and control of pyruvate dehydrogenase kinases and phosphatase isoform 1
Authors: Roche Thomas E. , Hiromasa Yasuaki , Turkan Ali , Gong Xiaoming , Peng Tao , Yan Xiaohua , Kasten Shane A. , Bao Haiying , Dong Jianchun
Published: December 2004

Four pyruvate dehydrogenase kinase and two pyruvate dehydrogenase phosphatase isoforms function in adjusting the activation state of the pyruvate dehydrogenase complex (PDC) through determining the fraction of active (nonphosphorylated) pyruvate dehydrogenase component. Necessary adaptations of PDC activity with varying metabolic requirements in different tissues and cell types are met by the selective expression and pronounced variation in the inherent functional properties and effector sensitivities of these regulatory enzymes. This review emphasizes how the foremost changes in the kinase and phosphatase activities issue from the dynamic, effector–modified interactions of these regulatory enzymes with the flexibly held outer domains of the core‐forming dihydrolipoyl acetyl transferase component.
Membrane targeting of a folded and cofactor‐containing protein
Authors: Brüser Thomas , Yano Takahiro , Brune Daniel C. , Daldal Fevzi
Published: December 2004

Targeting of proteins to and translocation across the membranes is a fundamental biological process in all organisms. In bacteria, the twin arginine translocation (Tat) system can transport folded proteins. Here, we demonstrate in vivo that the high potential iron‐sulfur protein (HiPIP) from Allochromatium vinosum is translocated into the periplasmic space by the Tat system of Escherichia coli. In vitro, reconstituted HiPIP precursor (preHoloHiPIP) was targeted to inverted membrane vesicles from E. coli by a process requiring ATP when the Tat substrate was properly folded. During membrane targeting, the protein retained its cofactor, indicating that it was targeted in a folded state. Membrane targeting did not require a twin arginine motif and known Tat system components. On the basis of these findings, we propose that a pathway exists for the insertion of folded cofactor‐containing proteins such as HiPIP into the bacterial cytoplasmic membrane.
The kinetic properties of various R258 mutants of deacetoxycephalosporin C synthase
Authors: Lee Hwei‐Jen , Dai Young‐Fung , Shiau Chia‐Yang , Schofield Christopher J. , Lloyd Matthew D.
Published: December 2004

Site‐directed mutagenesis was used to investigate the control of 2‐oxoacid cosubstrate selectivity by deacetoxycephalosporin C synthase. The wild‐type enzyme has a requirement for 2‐oxoglutarate and cannot efficiently use hydrophobic 2‐oxoacids (e.g. 2‐oxohexanoic acid, 2‐oxo‐4‐methyl‐pentanoic acid) as the cosubstrate. The following mutant enzymes were produced: R258A, R258L, R258F, R258H and R258K. All of the mutants have broadened cosubstrate selectivity and were able to utilize hydrophobic 2‐oxoacids. The efficiency of 2‐oxoglutarate utilization by all mutants was decreased as compared to the wild‐type enzyme, and in some cases activity was abolished with the natural cosubstrate.
Phenol hydroxylase from Acinetobacter radioresistens S13
Authors: Griva Ersilia , Pessione Enrica , Divari Sara , Valetti Francesca , Cavaletto Maria , Rossi Gian Luigi , Giunta Carlo
Published: December 2004

This paper reports the isolation and characterization of the regulatory moiety of the multicomponent enzyme phenol hydroxylase from Acinetobacter radioresistens S13 grown on phenol as the only carbon and energy source. The whole enzyme comprises an oxygenase moiety (PHO), a reductase moiety (PHR) and a regulatory moiety (PHI). PHR contains one FAD and one iron‐sulfur cluster, whose function is electron transfer from NADH to the dinuclear iron centre of the oxygenase. PHI is required for catalysis of the conversion of phenol to catechol in vitro, but is not required for PHR activity towards alternative electron acceptors such as cytochrome c and Nitro Blue Tetrazolium. The molecular mass of PHI was determined to be 10 kDa by SDS/PAGE, 8.8 kDa by MALDI‐TOF spectrometry and 18 kDa by gel‐permeation. This finding suggests that the protein in its native state is a homodimer. The isoelectric point is 4.1. PHI does not contain any redox cofactor and does not bind ANS, a fluorescent probe for hydrophobic sites. The N‐terminal sequence is similar to those of the regulatory proteins of phenol hydroxylase from A. calcoaceticus and Pseudomonas CF 600.

In the reconstituted system, optimal reaction rate was achieved when the stoichiometry of the components was 2 PHR monomers: 1 PHI dimer: 1 PHO (αβγ) dimer. PHI interacts specifically with PHR, promoting the enhancement of FAD fluorescence emission. This signal is diagnostic of a conformational change of PHR that might result in a better alignment with respect to PHO.
In vivo studies of altered expression patterns of p53 and proliferative control genes in chronic vitamin A deficiency and hypervitaminosis
Authors: Borrás Elisa , Zaragozá Rosa , Morante María , García Concha , Gimeno Amparo , López‐Rodas Gerardo , Barber Teresa , Miralles Vicente J. , Viña Juan R. , Torres Luis
Published: December 2004

Several clinical trials have revealed that individuals who were given β−carotene and vitamin A did not have a reduced risk of cancer compared to those given placebo; rather, vitamin A could actually have caused an adverse effect in the lungs of smokers [Omenn, G.S., Goodman, G.E., Thornquist, M.D., Balmes, J., Cullen, M.R., Glass, A., Keogh, J.P., Meyskens, F.L., Valanis, B., Williams, J.H., Barnhart, S. & Hammar, S. N. Engl. J. Med (1996) 334, 1150–1155; Hennekens, C.H., Buring, J.E., Manson, J.E., Stampfer, M., Rosner, B., Cook, N.R., Belanger, C., LaMotte, F., Gaziano, J.M., Ridker, P.M., Willet, W. & Peto, R. (1996) N. Engl. J. Med. 334, 1145–1149]. Using differential display techniques, an initial survey using rats showed that liver RNA expression of c‐H‐Ras was decreased and p53 increased in rats with chronic vitamin A deficiency. These findings prompted us to evaluate the expression of c‐Jun, p53 and p21WAF1/CIF1 (by RT‐PCR) in liver and lung of rats. This study showed that c‐Jun levels were lower and that p53 and p21WAF1/CIF1 levels were higher in chronic vitamin A deficiency. Vitamin A supplementation increased expression of c‐Jun, while decreasing the expression of p53 and p21WAF1/CIF1. Western‐blot analysis demonstrated that c‐Jun and p53 showed a similar pattern to that found in the RT‐PCR analyses. Binding of retinoic acid receptors (RAR) to the c‐Jun promoter was decreased in chronic vitamin A deficiency when compared to control hepatocytes, but contrasting results were found with acute vitamin A supplementated cells. DNA fragmentation and cytochrome c release from mitochondria were analyzed and no changes were found. In lung, an increase in the expression of c‐Jun produced a significant increase in cyclin D1 expression. These results may explain, at least in part, the conflicting results found in patients supplemented with vitamin A and illustrate that the changes are not restricted to lung. Furthermore, these results suggest that pharmacological vitamin A supplementation may increase the risk of adverse effects including the risk of oncogenesis.
Critical role of the plasma membrane for expression of mammalian mitochondrial side chain cleavage activity in yeast
Authors: Duport Catherine , Schoepp Barbara , Chatelain Elise , Spagnoli Roberto , Dumas Bruno , Pompon Denis
Published: December 2004

Engineered yeast cells efficiently convert ergosta‐5‐eneol to pregnenolone and progesterone provided that endogenous pregnenolone acetylase activity is disrupted and that heterologous sterol Δ7‐reductase, cytochrome P450 side chain cleavage (CYP11A1) and 3β hydroxysteroid dehydrogenase/isomerase (3β‐HSD) activities are present. CYP11A1 activity requires the expression of the mammalian NADPH‐adrenodoxin reductase (Adrp) and adrenodoxin (Adxp) proteins as electron carriers. Several parameters modulate this artificial metabolic pathway: the effects of steroid products; the availability and delivery of the ergosta‐5‐eneol substrate to cytochrome P450; electron flux and protein localization. CYP11A1, Adxp and Adrp are usually located in contact with inner mitochondrial membranes and are directed to the outside of the mitochondria by the removal of their respective mitochondrial targeting sequences. CYP11A1 then localizes to the plasma membrane but Adrp and Adxp are detected in the endoplasmic reticulum and cytosol as expected. The electron transfer chain that involves several subcellular compartments may control side chain cleavage activity in yeast. Interestingly, Tgl1p, a potential ester hydrolase, was found to enhance steroid productivity, probably through both the availability and/or the trafficking of the CYP11A1 substrate. Thus, the observation that the highest cellular levels of free ergosta‐5‐eneol are found in the plasma membrane suggests that the substrate is freely available for pregnenolone synthesis.
Lateral organization in Acholeplasma laidlawii lipid bilayer models containing endogenous pyrene probes
Authors: Storm Patrik , Li Lu , Kinnunen Paavo , Wieslander Åke
Published: December 2004

In membranes of the small prokaryote Acholeplasma laidlawii bilayer‐ and nonbilayer‐prone glycolipids are major species, similar to chloroplast membranes. Enzymes of the glucolipid pathway keep certain important packing properties of the bilayer in vivo, visualized especially as a monolayer curvature stress (‘spontaneous curvature’). Two key enzymes depend in a cooperative fashion on substantial amounts of the endogenous anionic lipid phosphatidylglycerol (PG) for activity. The lateral organization of five unsaturated A. laidlawii lipids was analyzed in liposome model bilayers with the use of endogenously produced pyrene‐lipid probes, and extensive experimental designs. Of all lipids analyzed, PG especially promoted interactions with the precursor diacylglycerol (DAG), as revealed from pyrene excimer ratio (Ie/Im) responses. Significant interactions were also recorded within the major nonbilayer‐prone monoglucosylDAG (MGlcDAG) lipids. The anionic precursor phosphatidic acid (PA) was without effects. Hence, a heterogeneous lateral lipid organization was present in these liquid‐crystalline bilayers. The MGlcDAG synthase when binding at the PG bilayer interface, decreased acyl chain ordering (increase of membrane free volume) according to a bis‐pyrene‐lipid probe, but the enzyme did not influence the bulk lateral lipid organization as recorded from DAG or PG probes. It is concluded that the concentration of the substrate DAG by PG is beneficial for the MGlcDAG synthase, but that binding in a proper orientation/conformation seems most important for activity.
Mapacalcine specifically blocks hypoxia‐induced calcium influx in rat hepatocytes
Authors: Crenesse Dominique , Neuilly Ghislaine , Gugenheim Jean , Ferre Catherine , Hugues Michel
Published: December 2004

Post ischaemic cell calcium invasion has been described as one of the main causes of graft failure. Protective effects of calcium antagonists have been investigated but are not convincing and their mechanisms of action remain unclear. In this work we tested the protective effect of a new calcium inhibitor described to block a calcium current insensitive to all known calcium blockers. Specific mapacalcine receptors were first characterized on rat hepatocytes membranes using the 125I‐labeled mapacalcine. 45Ca fluxes were then measured on cultured hepatocytes submitted (or not) to an hypoxic period. The action of mapacalcine was investigated on the ischaemia‐induced calcium influx. We demonstrate here that: (a) there are specific receptors for mapacalcine in rat hepatocytes; (b) Mapacalcine is able to specifically block ischaemia–induced calcium influx with an IC50 of 0.3 µm and does not significantly interact with the basal calcium flux.

Our work demonstrates that the mapacalcine receptor is a cellular structure directly involved in the phenomenon of postischaemic cell invasion by calcium. Specific block of ischaemia‐induced Ca2+ influx by mapacalcine suggests that the development of a panel of pharmacological drugs acting on this receptor could lead to the discovery of therapeutic agents able to protect cells against one of the events responsible for organ failure after transplantation or simply after an ischaemic period. Moreover, identification of the cellular protein which binds mapacalcine may become an important step in the research of mechanisms involved in postischaemic cell invasion by calcium.
Identification of amino acids in antiplasmin involved in its noncovalent ‘lysine‐binding‐site’‐dependent interaction with plasmin
Authors: Wang Haiyao , Yu Anna , Wiman Björn , Pap Sarolta
Published: December 2004

The lysine‐binding‐site‐mediated interaction between plasmin and antiplasmin is of great importance for the fast rate of this reaction. It also plays an important part in regulating the fibrinolytic enzyme system. To identify structures important for its noncovalent interaction with plasmin, we constructed seven single‐site mutants of antiplasmin by modifying charged amino acids in the C‐terminal part of the molecule. All the variants were expressed in the Drosophila S2 cell system, purified, and shown to form stable complexes with plasmin. A kinetic evaluation revealed that two mutants of the C‐terminal lysine (K452E or K452T) did not differ significantly from wild‐type antiplasmin in their reactions with plasmin, in either the presence or absence of 6‐aminohexanoic acid, suggesting that this C‐terminal lysine is not important for this reaction. On the other hand, modification of Lys436 to Glu decreased the reaction rate about fivefold compared with wild‐type. In addition, in the presence of 6‐aminohexanoic acid, only a small decrease in the reaction rate was observed, suggesting that Lys436 is important for the lysine‐binding‐site‐mediated interaction between plasmin and antiplasmin. Results from computerized molecular modelling of the C‐terminal 40 amino acids support our experimental data.
The protein tyrosine phosphatase PTP‐Basophil/Basophil‐like
Authors: S. Erdmann Kai
Published: December 2004

The protein tyrosine phosphatase PTP‐Basophil (PTP‐Bas) and its mouse homologue, PTP‐Basophil‐like (PTP‐BL), are high molecular mass protein phosphatases consisting of a number of diverse protein–protein interaction modules. Several splicing variants of these phosphatases are known to exist thus demonstrating the complexity of these molecules. PTP‐Bas/BL serves as a central scaffolding protein facilitating the assembly of a multiplicity of different proteins mainly via five different PDZ domains. Many of these interacting proteins are implicated in the regulation of the actin cytoskeleton. However, some proteins demonstrate a nuclear function of this protein tyrosine phosphatase. PTP‐Bas is involved in the regulation of cell surface expression of the cell death receptor, Fas. Moreover, it is a negative regulator of ephrinB phosphorylation, a receptor playing an important role during development. The phosphorylation status of other proteins such as RIL, IκBα and β‐catenin can also be regulated by this phosphatase. Finally, PTP‐BL has been shown to be involved in the regulation of cytokinesis, the last step in cell division. Although the precise molecular function of PTP‐Bas/BL is still elusive, current data suggest clearly that PTP‐Bas/BL belongs to the family of PDZ domain containing proteins involved in the regulation of the cytoskeleton and of intracellular vesicular transport processes.
Cytosol–mitochondria transfer of reducing equivalents by a lactate shuttle in heterotrophic Euglena
Authors: Jasso‐Chávez Ricardo , Moreno‐Sánchez Rafael
Published: December 2004

To assess the expression and physiological role of the mitochondrial NAD+‐independent lactate dehydrogenase (iLDH) in Euglena gracilis, cells were grown with different carbon sources, and the d‐ and l‐iLDH activities and several key metabolic intermediates were examined. iLDH activity was significant throughout the growth period, increasing by three‐ to fourfold from latency to the stationary phase. Intracellular levels of d‐ and l‐lactate were high (5–40 mm) from the start of the culture and increased (20–80 mm) when the stationary phase was entered. All external carbon sources were actively consumed, reaching a minimum upon entering the stationary phase, when degradation of paramylon started. The level of ATP was essentially unchanged under all experimental conditions. Oxalate, an inhibitor of iLDH, strongly inhibited oligomycin‐sensitive respiration and growth, whereas rotenone, an inhibitor of respiratory complex I, only slightly affected these parameters in lactate‐grown cells. Isolated mitochondria exhibited external NADH‐supported respiration, which was sensitive to rotenone and flavone, and an inability to oxidize pyruvate. Addition of cytosol, NADH and pyruvate to mitochondria incubated with rotenone and flavone prompted significant O2 uptake, which was blocked by oxalate. The data suggested that iLDH expression in Euglena is independent of substrate availability and that iLDHs play a key role in the transfer of reducing equivalents from the cytosol to the respiratory chain (lactate shuttle).
Development of a baculovirus‐based fluorescence resonance energy transfer assay for measuring protein–protein interaction
Authors: Cheung Timothy C. , Hearn John P.
Published: December 2004

A new baculovirus‐based fluorescence resonance energy transfer (Bv‐FRET) assay for measuring multimerization of cell surface molecules in living cells is described. It has been demonstrated that gonadotropin‐releasing hormone receptor (GnRH‐R) was capable of forming oligomeric complexes in the plasma membrane under normal physiological conditions. The mouse gonadotropin‐releasing hormone receptor GnRH‐R was used to evaluate the efficiency and potential applications of this assay. Two chimeric constructs of GnRH‐R were made, one with green fluorescent protein as a donor fluorophore and the other with enhanced yellow fluorescent protein as an acceptor fluorophore. These chimeric constructs were coexpressed in an insect cell line (BTI Tn5 B1‐4) using recombinant baculoviruses. Energy transfer occurred from the excited donor to the acceptor when they were in close proximity. The association of GnRH‐R was demonstrated through FRET and the fluorescence observed using a Leica TSC‐SPII confocal microscope. FRET was enhanced by the addition of a GnRH agonist but not by an antagonist. The Bv‐FRET assay constitutes a highly efficient, reliable and convenient method for measuring protein–protein interaction as the baculovirus expression system is superior to other transfection‐based methods. Additionally, the same insect cell line can be used routinely for expressing any recombinant proteins of interest, allowing various combinations of molecules to be tested in a rapid fashion for protein–protein interactions. The assay is a valuable tool not only for the screening of new molecules that interact with known bait molecules, but also for confirming interactions between other known molecules.
Skewed reproductive success among male white‐spotted charr land‐locked by an erosion control dam: Implications for effective population size
Authors: Maekawa Koji , Koseki Yusuke , Iguchi Kei'ichiro , Kitano Satoshi
Published: December 2004

In 1996 and 1997, the spawning behavior of fluvial white‐spotted charrSalvelinus leucomaenis, was observed in the upstream area of an erosion control dam. A small number of males with relatively large body size mated successfully with females as a pair, while almost all satellite males did not sneak successfully, resulting in a non‐random mating system. The low sneaking success of subordinate males, in addition to the monopolization of spawning opportunities by a few dominant males, is one of the most important causes of skewed reproductive success among males. The total number of adult fishes in the study area (N: approximately half of the whole tributary above a dam) was estimated as 148 and 102 in 1996 and 1997, respectively. Based on these findings and some further assumptions, the estimated effective population size (Ne) was low in both years. TheNe/Nratio ranged from 0.33 to 0.36 in both years. In addition to reduced population size by construction of an impassable dam, the above‐dam population suffered lowNedue to skewed reproductive success among males. The lowNemay be one cause of extinction in above‐dam populations of fluvial charr, especially just after the construction of impassable barriers.
Effect of fog on sea salt deposition on peat soil in boreal Picea glehnii forests in Ochiishi, eastern Hokkaido, Japan
Authors: Iyobe Tsutomu , Haraguchi Akira , Nishijima Hiroki , Tomizawa Hideo , Nishio Fumihiko
Published: December 2004

We investigated seasonal changes in the chemical properties of precipitation (bulk deposition, throughfall and stem flow) in Picea glehnii forests and neighboring Sphagnum communities in three ombrotrophic mires in Ochiishi district, northern Japan, to clarify the contribution of fog to nutrient addition to mires. Na+ and Cl– dominated the bulk deposition, followed by Mg2+, Ca2+ and SO42–, implying an oceanic influence on mire chemistry. Differences in chemical properties among bulk deposition, throughfall and stem flow increased with proximity to the coastline. There was little difference in electrical conductivity (EC) among bulk deposition, throughfall and stem flow during the period of high fog frequency, which was approximately 17 fog days per month from June to August, but there were large differences in EC during the period of low fog frequency, which was approximately 5 fog days per month from September to November. In general, throughfall and stem flow were enriched with Na+, Mg2+, Ca2+, Cl– and SO42– at the P. glehnii canopy, and seasonal trends in ionic concentration showed almost the same trend as EC. This seasonal pattern of atmospheric deposition chemistry showed that sea salt deposition on mires depends on fog occurrence. Sea salt is washed out of the atmosphere by fog when fog covers the forest canopy and, hence, throughfall and stem flow did not lead to the enrichment of chemical constituents during passage through the canopy in these mires during the season of high fog occurrence.
Size dependence of leaf area and the mass of component organs during a course of self‐thinning in a hinoki (Chamaecyparis obtusa) seedling population
Authors: Ogawa Kazuharu
Published: December 2004

The allometric equation,y = gxh, was applied monthly to the relationships between two different dimensions of tree seedlings of hinoki cypress (Chamaecyparis obtusa) during a course of self‐thinning from April 1990 to March 1991 to detect differences in biomass allocation among individuals. As theh‐value in the allometry of crown length and seedling height was greater than unity for all seasons, crown ratio became greater as seedling height increased. Leaf weight ratio increased with increasing seedling size because theh‐value in the allometry of leaf dry weight and whole seedling dry weight was greater than unity in every month. Therefore, smaller seedlings are disadvantageous to photosynthetic production by leaves. In contrast, the leaf area ratio was constant irrespective of seedling size because theh‐value in the allometry of leaf area and whole seedling dry weight was nearly equal to unity in most seasons. In addition, because theh‐value in the allometry of leaf area and leaf dry weight was less than unity in all seasons, specific leaf area decreased with an increase in leaf dry weight, indicating that smaller seedlings adapt to low light environments by possessing shade leaves. Root weight ratio decreased with increasing seedling size because theh‐value in the allometry of root dry weight and whole seedling dry weight was less than unity in most seasons.
A web application to manage a database for liquid nitrogen tanks
Authors: Picard Cyril , Picard Didier
Published: December 2004

We have developed a software, Cell Database, for archiving records about cells stored in liquid nitrogen tanks. Once installed on a web server, the database is accessed through a standard web browser. This user‐friendly and self‐explanatory application is independent of computer platform and periodic upgrades of a commercial software. Our web application allows import of data from other database programs and adaptation to different tank formats, types of samples, and archiving needs.
Thrombolysis for acute myocardial infarction in Australasia 1999
Authors: Mountain David , Jelinek George A , O'Brien Debra L , Ingarfield Sharyn L , Jacobs Ian G , Lynch Dania M
Published: December 2004

Objective: To describe revascularization practice for acute myocardial infarction in a sample of Australasian hospitals during 1999.

Design: Survey for the 1999 calendar year.

Setting: Hospitals with Australasian College for Emergency Medicine‐accredited emergency departments in Australia and New Zealand.

Participants: Forty‐eight hospitals of 80 surveyed (60%), comprising 15 tertiary and 33 non‐tertiary hospitals.

Main outcome measures: Time from arrival in emergency department to initiation of thrombolytic therapy, site of therapy, agent used, mortality and intracranial haemorrhage rates.

Results: Approximately 30% of patients with acute myocardial infarction had revascularization therapy. Sixty‐two per cent of patients receiving thrombolytics were given this treatment in the emergency department, the remainder in the coronary care unit. Overall median door‐to‐needle times were 35.0 min emergency department versus 48.3 min coronary care unit. Streptokinase was used for 58.3% of thrombolysis. In‐hospital mortality of thrombolysed patients was 6.7% in the emergency department versus 4.3% in the coronary care unit with intracranial haemorrhage rates of 0.8% emergency department and 0.7% coronary care unit.

Conclusions: Overall times to thrombolysis and outcome rates in this sample were within internationally reported figures. Emergency department times were shorter than in coronary care unit.
Otago Glaucoma Surgery Outcome Study. Atypical late failure of drainage following clear cornea trabeculectomy
Authors: Whittaker Karl W , Molteno Anthony CB , Bevin Tui H
Published: December 2004

Background: Bleb scarring is the major cause of late drainage failure following the standard trabeculectomy. To overcome this, Cairns described a modification of his original technique, which he termed the clear cornea trabeculectomy. The essential feature was communication between the anterior chamber and subconjunctival space without intraoperative disturbance of the conjunctival or Tenon's tissue. As there is little published data on Cairns’ clear cornea trabeculectomy, this study aimed to assess the long‐term success of this procedure relative to conventional trabeculectomy.

Methods: Patients who underwent clear cornea trabeculectomy at Dunedin Hospital were identified. Cases in which late failure occurred were subject to a detailed review. Records of all patients in whom late failure of drainage occurred following conventional trabeculectomy performed since 1985 were also reviewed. The nature of late drainage failure associated with these different procedures was assessed.

Results: Late failure of drainage occurred in three of 21 eyes following clear cornea trabeculectomy. In each case there was an accelerated drainage failure with a dramatic rise in intraocular pressure. Consequent visual loss occurred in two patients. Late failure occurred in 32 of the 450 cases of conventional trabeculectomy, in all of which the pressure rise was gradual and less acute.

Conclusions: This report highlights a previously unreported type of late failure associated with clear cornea trabeculectomy, which may result in significant visual loss. This reinforces the view that the standard Cairns’ trabeculectomy is a safer procedure.
Tripterygium glycosides suppress production of interleukin‐4 by splenocytes in oxazolone‐induced murine colitis
Authors: HAN Ying , CHEN Gang , SONG Ying Xin , MURATA Yuhji , ITOH Jugoh , MUNAKATA Akihiro
Published: December 2004

OBJECTIVE:  To investigate the in vitro effect of Tripterygium glycosides (TG) on cytokine production by splenocytes in oxazolone (OXZ)‐induced colitis in mice.

METHODS:  Oxazolone (6 mg in 50% ethanol) was administered to male SJL/J mice intrarectally to induce colitis and the mice were killed 3 days later. Isolated splenocytes were cultured for 24 h in the presence of phorbol myristate acetate and ionomycin. A preparation of Tripterygium glycosides at a concentration of either 0.1 mg/mL or 0.01 mg/mL was added to the culture medium of splenocytes. Production of interferon gamma (IFN‐γ) and interleukin‐4 (IL‐4) in the supernatant were measured by ELISA.

RESULTS:  Production of IFN‐γ in the normal control group was suppressed by TG at both concentrations (0.01 and 0.1 mg/mL; 1.24 ± 0.13 pg/mL (samples without TG) → 0.97 ± 0.26 pg/mL (0.01 mg/mL TG) → 0.87 ± 0.18 pg/mL (0.1 mg/mL TG); P < 0.02) in a dose dependent manner. In the OXZ‐induced colitis group, the basic level of IFN‐γ was significantly lower than that of the normal control group (1.24 ± 0.13 pg/mL vs 0.65 ± 0.08 pg/mL; P < 0.01); but IL‐4 production was significantly increased in the OXZ‐induced colitis without TG group (7.83 ± 0.69 pg/mL vs 5.65 ± 0.48 pg/mL, P < 0.01). In both groups, TG suppressed IL‐4 production in a dose‐dependent manner (normal control group: 5.65 ± 0.48 pg/mL (samples without TG) → 4.97 ± 0.38 pg/mL (0.01 mg/mL TG) → 3.98 ± 0.32 pg/mL (0.1 mg/mL TG), P < 0.01; OXZ group: 7.83 ± 0.69 pg/mL (samples without TG) → 7.07 ± 0.47 pg/mL (0.01 mg/mL TG) → 6.35 ± 0.48 pg/mL (0.1 mg/mL TG), P < 0.01).

CONCLUSION:  Oxazalone‐induced IL‐4 overproduction by splenocytes was significantly suppressed by TG in a dose dependent manner and the beneficial effects of TG on ulcerative colitis might be related to the suppression of the Th2 type (e.g. IL‐4) mediated immunological response of splenocytes.
Aberrant responses to acoustic stimuli in mice deficient for neural recognition molecule NB‐2
Authors: Li Hong , Takeda Yasuo , Niki Hiroaki , Ogawa Junko , Kobayashi Satoru , Kai Nobuyuki , Akasaka Keiko , Asano Masahide , Sudo Katsuko , Iwakura Yoichiro , Watanabe Kazutada
Published: December 2004

NB‐2, a member of the contactin subgroup in the immunoglobulin superfamily, is expressed specifically in the postnatal nervous system, reaching a maximum level at 3 weeks postnatal. NB‐2 displays neurite outgrowth‐promoting activity in vitro. To assess its function in the nervous system, we generated mutant mice in which a part of the NB‐2 gene was ablated and replaced with the tau‐LacZ gene. The general appearance of NB‐2‐deficient mice and their gross anatomical features were normal. The LacZ expression patterns in heterozygous mice revealed that NB‐2 is preferentially expressed in the central auditory pathways. In the audiogenic seizure test, NB‐2‐deficient mice exhibited a lower incidence of wild running, but a higher mortality rate than the wild‐type littermates. c‐Fos immunohistochemistry demonstrated that neural excitability induced by the audiogenic seizure test in the NB‐2‐deficient mice was prominently attenuated in both the dorsal and external cortices of the inferior colliculus, where enhanced neural excitability was observed in the wild‐type mice. In response to pure‐tone stimulation after priming, NB‐2‐deficient mice exhibited a diffuse and low level of c‐Fos expression in the central nucleus of the inferior colliculus, which was distinctly different from the band‐like c‐Fos expression corresponding to the tonotopic map in the wild‐type littermates. Taken together, these results suggest that a lack of NB‐2 causes impairment of the neuronal activity in the auditory system.
Spreading of slow cortical rhythms to the basal ganglia output nuclei in rats with nigrostriatal lesions
Authors: Belluscio Mariano A. , Kasanetz Fernando , Riquelme Luis A. , Gustavo Murer M.
Published: December 2004

A high proportion of neurons in the basal ganglia display rhythmic burst firing after chronic nigrostriatal lesions. For instance, the periodic bursts exhibited by certain striatal and subthalamic nucleus neurons in 6‐hydroxydopamine‐lesioned rats seem to be driven by the ∼ 1 Hz high‐amplitude rhythm that is prevalent in the cerebral cortex of anaesthetized animals. Because the striatum and subthalamic nucleus are the main afferent structures of the substantia nigra pars reticulata, we examined the possibility that the low‐frequency modulations (periodic bursts) that are evident in approximately 50% nigral pars reticulata neurons in the parkinsonian condition were also coupled to this slow cortical rhythm. By recording the frontal cortex field potential simultaneously with single‐unit activity in the substantia nigra pars reticulata of anaesthetized rats, we proved the following. (i) The firing of nigral pars reticulata units from sham‐lesioned rats is not coupled to the ∼ 1 Hz frontal cortex slow oscillation. (ii) Approximately 50% nigral pars reticulata units from 6‐hydroxydopamine‐lesioned rats oscillate synchronously with the ∼ 1 Hz cortical rhythm, with the cortex leading the substantia nigra by ∼ 55 ms; the remaining ∼ 50% nigral pars reticulata units behave as the units recorded from sham‐lesioned rats. (iii) Periodic bursting in nigral pars reticulata units from 6‐hydroxydopamine‐lesioned rats is disrupted by episodes of desynchronization of cortical field potential activity. Our results strongly support that nigrostriatal lesions promote the spreading of low‐frequency cortical rhythms to the substantia nigra pars reticulata and may be of outstanding relevance for understanding the pathophysiology of Parkinson's disease.
Stimulation site determines the conditioned effects of kindling in rats: anterior neocortex versus amygdala
Authors: Barnes Steven J. , Pinel John P. J. , Wig Gagan S. , Stuettgen Maik C. , Hölzel C. Heike
Published: December 2004

Rats received 53 stimulations to either the left basolateral amygdala (BA) or left anterior neocortex (AN) in one environment (CS+) and 53 sham stimulations (the stimulation lead was attached but no current was delivered) in another environment (CS–), quasirandomly over 54 days. Confirming a previous report [Barnes, S.J., Pinel, J.P., Francis, L.H. & Wig, G.S. (2001) Behav. Neurosci., 115, 1065–1072], as BA kindling progressed, the CS+ began to elicit more defensive behaviours (i.e. less activity, more freezing and avoidance of the CS+) than the CS–, and at the end of the experiment, convulsions elicited in the CS+ were more severe than those elicited in the CS–. Like BA kindling, AN kindling led to less activity in the CS+; but unlike BA kindling, AN kindling led to more wet‐dog‐shakes and less, rather than more, severe convulsions in the CS+. During AN kindling, the mean number of wet‐dog‐shakes in the CS+ was negatively correlated with the mean convulsion class, suggesting that wet‐dog‐shakes contribute to the inherent variability of AN kindling. These findings confirm that inherent conditioned effects influence kindled convulsions and interictal behaviour and establish for the first time that the pattern of these conditioned effects is a function of the kindling site.
Differential expression and cellular localization of doublecortin in the developing rat retina
Authors: Lee Eun‐Jin , Kim In‐Beom , Lee Eun , Kwon Sung‐Oh , Oh Su‐Ja , Chun Myung‐Hoon
Published: December 2004

Doublecortin is 40 kDa microtubule‐associated phosphoprotein required for neuronal migration and differentiation in various regions of the developing central nervous system. We have investigated the expression and cellular localization of doublecortin in the developing rat retina using immunocytochemistry and Western blot analysis. The expression of doublecortin was high from embryonic day 18 (E18) until E20 and was low during the postnatal period. The doublecortin immunoreactivity first appeared in a few radially orientated cells in the mantle zone of the primitive retina at E15. From E16 onward, the immunoreactivity appeared in two different regions: the inner part of the retina and middle of the neuroblastic layer. In the inner part, the somata of cells in the ganglion cell layer, in the distal row of the neuroblastic layer and profiles in the inner plexiform layer showed doublecortin immunoreactivity up to postnatal day 1 (P1). Afterwards, the doublecortin immunoreactivity persisted in the inner plexiform layer until P15, although the intensity decreased gradually with the maturation of the retina. In the middle of the neuroblastic layer, doublecortin immunoreactivity appeared in the radially orientated cells. These cells transformed into horizontal cells. The doublecortin immunoreactivity persisted in these cells up to P21. Given these results, doublecortin may play an important role in the migration and differentiation of specific neuronal populations in developmental stages of the rat retina.
Dentate granule cell GABAA receptors in epileptic hippocampus: enhanced synaptic efficacy and altered pharmacology
Authors: Cohen Akiva S. , Lin Dean D. , Quirk Gerald L. , Coulter Douglas A.
Published: December 2004

The dentate gyrus (DG) normally functions as a filter, preventing propagation of synchronized activity into the seizure‐prone hippocampus. This filter or ‘gatekeeper’ attribute of the DG is compromised in various pathological states, including temporal lobe epilepsy (TLE). This study examines the role that altered inhibition may play in the deterioration of this crucial DG function. Using the pilocarpine animal model of TLE, we demonstrate that inhibitory synaptic function is altered in principal cells of the DG. Spontaneous miniature inhibitory postsynaptic currents (mIPSCs) recorded in dentate granule cells (DGCs) from epileptic animals were larger, more sensitive to blockade by zinc and less sensitive to augmentation by the benzodiazepine type site 1 modulator zolpidem. Furthermore, mIPSCs examined during a quiescent period following injury but preceding onset of epilepsy were significantly smaller than those present either in control or in TLE DGCs, and had already acquired sensitivity to blockade by zinc prior to the onset of spontaneous seizures. Rapid agonist application experiments demonstrated that prolonged (>35 ms) exposure to zinc is required to block GABAA receptors (GABAARs) in patches pulled from epileptic DGCs. Therefore, zinc must be tonically present to block DGC GABAARs and alter DG function. This would occur only during repetitive activation of mossy fibres. Thus, in the pilocarpine animal model of TLE, an early, de novo, expression of zinc‐sensitive GABAARs is coupled with delayed, epilepsy‐induced development of a zinc delivery system provided by aberrant sprouting of zinc‐containing mossy fibre recurrent collaterals. The temporal and spatial juxtaposition of these pathophysiological alterations may compromise normal ‘gatekeeper’ function of the DG through dynamic zinc‐induced failure of inhibition, predisposing the hippocampal circuit to generate seizures.
Dissociation between mesocortical dopamine release and fear‐related behaviours in two psychogenetically selected lines of rats that differ in coping strategies to aversive conditions
Authors: Giorgi O. , Lecca D. , Piras G. , Driscoll P. , Corda M. G.
Published: December 2004

The mesocortical and mesolimbic dopaminergic (DAergic) pathways are activated by either aversive or rewarding stimuli. The functional tone of these DAergic neurons also increases during the execution of cognitive tasks. The present study was designed to examine the relationship between mesocortical and mesolimbic DAergic function and the expression of fear‐related behaviours as compared with attention‐ and cognition‐related mechanisms (e.g. coping strategies), in response to aversive conditions. To this aim, we used two psychogenetically selected rat lines, Roman high‐avoidance (RHA/Verh) and Roman low‐avoidance (RLA/Verh), which display drastically different emotion‐ and coping‐related behaviours in response to stressors: RLA/Verh rats are ‘reactive copers’ and more fearful than RHA/Verh rats, which are ‘proactive copers’. Brain dialysis experiments demonstrated that tail‐pinch (TP) and the anxiogenic compounds pentylenetetrazol (PTZ) and ZK 93426 increased DA output in the medial prefrontal cortex (PFCX) of RHA/Verh but not RLA/Verh, rats. In contrast, in the shell compartment of the nucleus accumbens (NAC shell), TP caused a small increase in DA output only in RLA/Verh rats, whereas PTZ and ZK 93426 had no significant effect on either line. RHA/Verh rats displayed more robust and longer lasting coping activity and less frequent freezing and self‐grooming episodes than did RLA/Verh rats after TP, PTZ or ZK 93426. This dissociation between fear‐related behaviour and cortical DAergic activation argues against the view that the latter may be involved in the control of fear‐like responses. We therefore propose that the activation of mesocortical DAergic projections by aversive stimuli underlies the cognitive mechanisms that are triggered in an attempt to gain control over the stressor.
Facilitative role of endogenous oxytocin in noradrenaline release in the rat supraoptic nucleus
Authors: Onaka Tatsushi , Ikeda Keiko , Yamashita Tomoko , Honda Kazufumi
Published: December 2004

Oxytocin is released not only from the axon terminals in the neurothypophysis but also from the dendrites in the hypothalamus. In the present study, we examined the role of dendritic oxytocin release in regulating presynaptic noradrenaline release within the hypothalamus. In vivo microdialysis experiments showed that local application of oxytocin augmented high‐K+‐induced noradrenaline release in the hypothalamic supraoptic nucleus. Oxytocin application to the hypothalamic synaptosomal preparation in vitro also potentiated high‐K+‐induced noradrenaline release. The effect of oxytocin was dose‐dependent and was blocked by an oxytocin receptor antagonist. We then examined roles of oxytocin released from the dendrites using in vivo microdialysis. Local application of an oxytocin receptor antagonist impaired noradrenaline release in the supraoptic nucleus in response to high‐K+ solution or noxious stimuli. An i.c.v. injection of an oxytocin receptor antagonist also impaired oxytocin release from the pituitary after noxious stimuli. These data suggest that dendritic oxytocin facilitates activation of oxytocin neurons, at least in part by augmentation of noradrenaline release via a presynaptic action.
Two variants of the rat brain sodium‐driven chloride bicarbonate exchanger (NCBE): developmental expression and addition of a PDZ motif
Authors: Giffard Rona G. , Lee Yong‐Sun , Ouyang Yi‐Bing , Murphy Sherry L. , Monyer Hannah
Published: December 2004

Regulation of pH in the central nervous system is critical to normal brain function and response to pathophysiological conditions. Here we identify two novel variants of the sodium‐driven chloride bicarbonate exchanger (NCBE) from brain. The developmental expression pattern seen byin situhybridization for the 90‐bp containing insert (insert A) reveals strong expression in spinal cord and brain beginning in embryonic development. High‐level expression is seen in cerebellar Purkinje cells and principal cells in hippocampus. The variant missing a 39‐bp insert at the 3′ end (insert B) encodes a protein in which the deduced carboxyterminal three amino acids are replaced with a unique 21 amino acid stretch terminating in a PDZ motif. rb2NCBE, the PDZ motif‐encoding variant, is more highly expressed in astrocytes than is rb1NCBE. Both variants are expressed at similar levels in neurons. Expression varies with age and cell type. The FLAG epitope was fused in‐frame at the amino terminus and each variant was expressed using a retroviral vector to study subcellular localization. Both variants were associated with the plasma membrane, but rb2NCBE colocalized with actin filaments to a greater extent, suggesting the PDZ form may interact with the cytoskeleton, whereas rb1NCBE was more often seen in intracellular vesicles. The PDZ motif‐containing variant was much more active in pH regulation, with the expected ionic dependence on Na+, HCO3−and Cl−when expressed in 3T3 cells. These results are a first step towards understanding the regulation of expression and activity of this transporter in the brain.