bluuebunny/crossref_metadata_2025 huggingface dataset:
Avian uncoupling protein expressed in yeast mitochondria prevents endogenous free radical damage
Authors: Criscuolo François , Gonzalez-Barroso Maria del Mar , Maho Yvon Le , Ricquier Daniel , Bouillaud Frederic
Published: May 2005

The longevity of birds is surprising since they exhibit high metabolic rates and elevated blood sugar levels compared with mammals of the same body size, which presumably expose them to higher rates of free oxygen radical production, which is implicated in accelerated senescence. Uncoupling proteins (UCPs) are transporters of the inner mitochondrial membrane and their physiological activity is still a subject of debate. Avian UCP was found in birds but data on its activity are scarce. Avian UCP (
Gallus gallus
) was overexpressed in yeast and we assessed its ability to prevent mitochondrial reactive oxygen species (ROS) production by measuring ROS damage (aconitase activity) and antioxidant defences (MnSOD activity). We show that avian UCP protects yeast mitochondria against the deleterious impact of ROS, but without stimulation of superoxide dismutase activity. Avian UCP protein was specifically immunodetected and retinoic acid, which belongs to the carotenoid family, was found to trigger its activity. These data show that avian UCP basal activity protects against ROS damage. However, when activated by retinoic acid, avian UCP can also operate as the mammalian thermogenic UCP1. The hypothesis that avian UCP activities are state- and species-dependent is further discussed.
Computational approaches to the determination of active site structures and reaction mechanisms in heterogeneous catalysts
Authors: Catlow C.R.A , French S.A , Sokol A.A , Thomas J.M
Published: May 2005

We apply quantum chemical methods to the study of active site structures and reaction mechanisms in mesoporous silica and metal oxide catalysts. Our approach is based on the use of both molecular cluster and embedded cluster (QM/MM) techniques, where the active site and molecular complex are described using density functional theory (DFT) and the embedding matrix simulated by shell model potentials. We consider three case studies: alkene epoxidation over the microporous TS-1 catalyst; methanol synthesis on ZnO and Cu/ZnO and C–H bond activation over Li-doped MgO.
Diversity and redundancy in bacterial chromosome segregation mechanisms
Authors: Errington Jeff , Murray Heath , Wu Ling Juan
Published: May 2005

Bacterial cells are much smaller and have a much simpler overall structure and organization than eukaryotes. Several prominent differences in cell organization are relevant to the mechanisms of chromosome segregation, particularly the lack of an overt chromosome condensation/decondensation cycle and the lack of a microtubule-based spindle. Although bacterial chromosomes have a rather dispersed appearance, they nevertheless have an underlying high level of spatial organization. During the DNA replication cycle, early replicated (oriC) regions are localized towards the cell poles, whereas the late replicated terminus (terC) region is medially located. This spatial organization is thought to be driven by an active segregation mechanism that separates the sister chromosomes continuously as replication proceeds. Comparisons of various well-characterized bacteria suggest that the mechanisms of chromosome segregation are likely to be diverse, and that in many bacteria, multiple overlapping mechanisms may contribute to efficient segregation. One system in which the molecular mechanisms of chromosome segregation are beginning to be elucidated is that of sporulating cells ofBacillus subtilis. The key components of this system have been identified, and their functions are understood, in outline. Although this system appears to be specialized, most of the functions are conserved widely throughout the bacteria.
Chromosome bi-orientation on the mitotic spindle
Authors: Tanaka Tomoyuki U
Published: May 2005

For proper chromosome segregation, sister kinetochores must attach to microtubules extending from opposite spindle poles prior to anaphase onset. This state is called sister kinetochore bi-orientation or chromosome bi-orientation. The mechanism ensuring chromosome bi-orientation lies at the heart of chromosome segregation, but is still poorly understood. Recent evidence suggests that mal-oriented kinetochore-to-pole connections are corrected in a tension-dependent mechanism. The cohesin complex and the Ipl1/Aurora B protein kinase seem to be key regulators for this correction. In this article, I discuss how cells ensure sister kinetochore bi-orientation for all chromosomes, mainly focusing on our recent findings in budding yeast.
The HiPIP from the acidophilic Acidithiobacillus ferrooxidans is correctly processed and translocated in Escherichia coli, in spite of the periplasm pH difference between these two micro-organisms
Authors: Bruscella Patrice , Cassagnaud Laure , Ratouchniak Jeanine , Brasseur Gaël , Lojou Elisabeth , Amils Ricardo , Bonnefoy Violaine
Published: May 2005

The gene encoding a putative high-potential iron–sulfur protein (HiPIP) from the strictly acidophilic and chemolithoautotrophicAcidithiobacillus ferrooxidansATCC 33020 has been cloned and sequenced. This potential HiPIP was overproduced in the periplasm of the neutrophile and heterotrophEscherichia coli. As shown by optical and EPR spectra and by electrochemical studies, the recombinant protein has all the biochemical properties of a HiPIP, indicating that the iron–sulfur cluster was correctly inserted. Translocation of this protein in the periplasm ofE. coliwas not detected in a ΔtatCmutant, indicating that it is dependent on the Tat system. The genetic organization of theirolocus in strains ATCC 23270 and ATCC 33020 is different from that found in strains Fe-1 and BRGM. Indeed, inA. ferrooxidansATCC 33020 and ATCC 23270 (the type strain),irowas not located downstream frompurAbut was instead downstream frompetC2, encoding cytochromec1from the secondA. ferrooxidanscytochromebc1complex. These findings underline the genotypic heterogeneity within theA. ferrooxidansspecies. The results suggest that Iro transfers electrons from a cytochromebc1complex to a terminal oxidase, as proposed for the HiPIP in photosynthetic bacteria.
The putative vacuolar ATPase subunit Vma7p of Candida albicans is involved in vacuole acidification, hyphal development and virulence
Authors: Poltermann Sophia , Nguyen Monika , Günther Juliane , Wendland Jürgen , Härtl Albert , Künkel Waldemar , Zipfel Peter F. , Eck Raimund
Published: May 2005

The vacuolar H+-ATPase (V-ATPase) component Vma7p of the human-pathogenic yeastCandida albicansregulates hyphal growth induced by serum and Spider medium and is essential for virulence. In order to characterize the functions of the putative V-ATPase subunit Vma7p ofC. albicans, null mutants were generated. The resulting mutants showed reduced vacuole acidification, which correlated with defective growth at alkaline pH. In addition, defects in degradation of intravacuolar putative endosomal structures were observed.vma7null mutants were sensitive towards the presence of metal ions. It is concluded that the sequestration of toxic ions in the vacuole via a H+gradient generated by the V-ATPase is affected. Thevma7null mutant strains were avirulent in a mouse model of systemic candidiasis. In addition,C. albicans vma7null mutants and the null mutant strain of the Vma7p-interacting phosphatidylinositol 3-kinase Vps34p showed similar phenotypes. In summary, the V-ATPase subunit Vma7p is involved in vacuolar ion transport and this transport is required for hyphal growth and virulence ofC. albicans.
Evidence of a charge-density threshold for optimum efficiency of biocidal cationic surfaces
Authors: Kügler R. , Bouloussa O. , Rondelez F.
Published: May 2005

The deposition of organic monolayers containing quaternary ammonium groups has been shown by many authors to confer biocidal properties on a large variety of solid surfaces. In a search for the controlling factors, the authors have grafted quaternized poly(vinylpyridine) chains on glass surfaces by two different methods and varied the charge density within the organic layer between 1012 and 1016 positive charges per cm2. The measurements show that this parameter has a large influence on the killing efficiency. Bacterial death occurs in less than 10 min in the quiescent state above a threshold value. The value is smaller for bacteria in the growth state. It also depends on the bacterial type. An electrostatic mechanism based on the exchange of counterions between the functionalized cationic surface and the bacterial membrane is proposed and appears consistent with the results.
Effect of carbon source on the cellulosomal subpopulations of Clostridium cellulovorans
Authors: Han Sung O. , Yukawa Hideaki , Inui Masayuki , Doi Roy H.
Published: May 2005

Clostridium cellulovoransproduces a cellulase enzyme complex called the cellulosome. When cells were grown on different carbon substrates such as Avicel, pectin, xylan, or a mixture of all three, the subunit composition of the cellulosomal subpopulations and their enzymic activities varied significantly. Fractionation of the cellulosomes (7–11 fractions) indicated that the cellulosome population was heterogeneous, although the composition of the scaffolding protein CbpA, endoglucanase EngE and cellobiohydrolase ExgS was relatively constant. One of the cellulosomal fractions with the greatest endoglucanase activity also showed the highest or second highest cellulase activity under all growth conditions tested. The cellulosomal fractions produced from cells grown on a mixture of carbon substrates showed the greatest cellulase activity and contained CbpA, EngE/EngK, ExgS/EngH and EngL. High xylanase activity in cellulose, pectin and mixed carbon-grown cells was detected with a specific cellulosomal fraction which had relatively larger amounts of XynB, XynA and unknown proteins (35–45 kDa). These resultsin totoindicate that the assembly of cellulosomes occurs in a non-random fashion.
Mechanism of internalization of the cytolethal distending toxin of Actinobacillus actinomycetemcomitans
Authors: Akifusa Sumio , Heywood Wendy , Nair Sean P. , Stenbeck Gudrun , Henderson Brian
Published: May 2005

Cytolethal distending toxin (CDT), which is encoded by three genes,cdtA,cdtBandcdtC, is now recognized to have a growing list of biological actions, including inhibition of cell cycle progression, promotion of apoptosis and stimulation of cytokine secretion. It appears that internalization of CDT is essential, at least for cell cycle blockade. Using purified recombinant CDT proteins from the periodontopathic bacteriumActinobacillus actinomycetemcomitans, the authors investigated which combination of toxin proteins produce cell cycle inhibition and which bound and/or entered into host cells. No evidence was found that CdtB bound to HEp-2 human epithelial cells. In contrast, both CdtA and CdtC bound to these cells. Induction of cell cycle arrest required that cells be exposed to both CdtB and CdtC. Pre-exposure of cells to CdtC for as little as 10 min, followed by removal of the free CdtC and addition of exogenous CdtB, resulted in the inhibition of cell cycle progression, suggesting that CdtB could bind to cell-surface-located CdtC. Using various methods to follow internalization of the CDT proteins it was concluded that CdtC acts to bind CdtB at the cell surface and transports it into the cell as a complex via an endosomal pathway blockable by monensin and brefeldin A.
Hydrogen concentrations in methane-forming cells probed by the ratios of reduced and oxidized coenzyme F420
Authors: de Poorter Linda M. I. , Geerts Wim J. , Keltjens Jan T.
Published: May 2005

Coenzyme F420is the central low-redox-potential electron carrier in methanogenic metabolism. The coenzyme is reduced under hydrogen by the action of F420-dependent hydrogenase. The standard free-energy change at pH 7 of F420reduction was determined to be −15 kJ mol−1, irrespective of the temperature (25–65 °C). Experiments performed with methane-forming cell suspensions ofMethanothermobacter thermautotrophicusincubated under various conditions demonstrated that the ratios of reduced and oxidized F420were in thermodynamic equilibrium with the gas-phase hydrogen partial pressures. During growth in a fed-batch fermenter, ratios changed in connection with the decrease in dissolved hydrogen. For most of the time, the changes were as expected for thermodynamic equilibrium between the oxidation state of F420inside the cells and extracellular hydrogen. Also, methanol-metabolizing, but not acetate-converting, cells ofMethanosarcina barkerimaintained the ratios of reduced and oxidized coenzyme F420in thermodynamic equilibrium with external hydrogen. The results of the study demonstrate that F420is a useful probe to assessin situhydrogen concentrations in H2-metabolizing methanogens.
SoxRS-mediated regulation of chemotrophic sulfur oxidation in Paracoccus pantotrophus
Authors: Rother Dagmar , Orawski Grazyna , Bardischewsky Frank , Friedrich Cornelius G.
Published: May 2005

Paracoccus pantotrophus GB17 requires thiosulfate for induction of the sulfur-oxidizing (Sox) enzyme system. The soxRS genes are divergently oriented to the soxVWXYZA–H genes. soxR predicts a transcriptional regulator of the ArsR family and soxS a periplasmic thioredoxin. The homogenote mutant GBΩS carrying a disruption of soxS by the Ω-kanamycin-resistance-encoding interposon expressed a low thiosulfate-oxidizing activity under heterotrophic and mixotrophic growth conditions. This activity was repressed by complementation with soxR, suggesting that SoxR acts as a repressor and SoxS is essential for full expression. Sequence analysis uncovered operator characteristics in the intergenic regions soxS–soxV and soxW–soxX. In each region a transcription start site was identified by primer extension analysis. Both regions were cloned into the vector pRI1 and transferred to P. pantotrophus. Strains harbouring pRI1 with soxS–soxV or soxW–soxX expressed the sox genes under heterotrophic conditions at a low rate, indicating repressor titration. Sequence analysis of SoxR suggested a helix–turn–helix (HTH) motif at position 87–108 and uncovered an invariant Cys-80 and a cysteine residue at the C-terminus. SoxR was overproduced in Escherichia coli with an N-terminal His6-tag and purified to near homogeneity. Electrophoretic gel mobility shift assays with SoxR retarded the soxS–soxV region as a single band while the soxW–soxX region revealed at least two protein–DNA complexes. These data demonstrated binding of SoxR to the relevant DNA. This is believed to be the first report of regulation of chemotrophic sulfur oxidation at the molecular level.
Allosteric NADP-glutamate dehydrogenase from aspergilli: purification, characterization and implications for metabolic regulation at the carbon–nitrogen interface
Authors: Noor Shahid , Punekar Narayan S.
Published: May 2005

NADP-dependent glutamate dehydrogenase (NADP-GDH) mediates fungal ammonium assimilation through reductive synthesis of glutamate from 2-oxoglutarate. By virtue of its position at the interface of carbon and nitrogen metabolism, biosynthetic NADP-GDH is a potential candidate for metabolic control. In order to facilitate characterization, a new and effective dye-affinity method was devised to purify NADP-GDH from two aspergilli,Aspergillus nigerandAspergillus nidulans. TheA. nigerNADP-GDH was characterized at length and its kinetic interaction constants with glutamate (Km34·7 mM) and ammonium (Km1·05 mM;Ki0·4 mM) were consistent with an anabolic role. Isophthalate, 2-methyleneglutarate and 2,4-pyridinedicarboxylate were significant inhibitors, with respectiveKivalues of 6·9, 9·2 and 202·0 μM. TheA. nigerenzyme showed allosteric properties and a sigmoid response (nH=2·5) towards 2-oxoglutarate saturation. The co-operative behaviour was a feature common to NADP-GDH fromAspergillus awamori,A. nidulansandAspergillus oryzae. NADP-GDH may therefore be a crucial determinant in adjusting 2-oxoglutarate flux between the tricarboxylic acid cycle and glutamate biosynthesis in aspergilli.
Daptomycin biosynthesis in Streptomyces roseosporus: cloning and analysis of the gene cluster and revision of peptide stereochemistry
Authors: Miao Vivian , Coëffet-LeGal Marie-Françoise , Brian Paul , Brost Renee , Penn Julia , Whiting Andrew , Martin Steven , Ford Robert , Parr Ian , Bouchard Mario , Silva Christopher J. , Wrigley Stephen K. , Baltz Richard H.
Published: May 2005

Daptomycin is a 13 amino acid, cyclic lipopeptide produced by a non-ribosomal peptide synthetase (NRPS) mechanism inStreptomyces roseosporus. A 128 kb region ofS. roseosporusDNA was cloned and verified by heterologous expression inStreptomyces lividansto contain the daptomycin biosynthetic gene cluster (dpt). The cloned region was completely sequenced and three genes (dptA,dptBC,dptD) encoding the three subunits of an NRPS were identified. The catalytic domains in the subunits, predicted to couple five, six or two amino acids, respectively, included a novel activation domain and amino-acid-binding pocket for incorporating the unusual amino acidl-kynurenine (Kyn), three types of condensation domains and an extra epimerase domain (E-domain) in the second module. Novel genes (dptE,dptF) whose products likely work in conjunction with a unique condensation domain to acylate the first amino acid, as well as other genes (dptI,dptJ) probably involved in supply of the non-proteinogenic amino acidsl-3-methylglutamic acid and Kyn, were located next to the NRPS genes. The unexpected E-domain suggested that daptomycin would haved-Asn, rather thanl-Asn, as originally assigned, and this was confirmed by comparing stereospecific synthetic peptides and the natural product both chemically and microbiologically.
Overproduction, purification and characterization of FgaPT2, a dimethylallyltryptophan synthase from Aspergillus fumigatus
Authors: Unsöld Inge A. , Li Shu-Ming
Published: May 2005

A putative dimethylallyltryptophan synthase gene,fgaPT2, was identified in the genome sequence ofAspergillus fumigatus.fgaPT2was cloned and overexpressed inSaccharomyces cerevisiae. The protein FgaPT2 was purified to near homogeneity and characterized biochemically. This enzyme was found to convertl-tryptophan to 4-dimethylallyltryptophan, a reaction known to be the first step in ergot alkaloid biosynthesis. FgaPT2 is a soluble, dimeric protein with a subunit size of 52 kDa, and contains no putative prenyl diphosphate binding site (N/D)DXXD.Kmvalues forl-tryptophan and dimethylallyl diphosphate (DMAPP) were determined as 8 and 4 μM, respectively. Metal ions, such as Mg2+and Ca2+, enhance the reaction velocity, but are not essential for the enzymic reaction. FgaPT2 showed a relatively strict substrate specificity for both tryptophan and DMAPP. FgaPT2 is the first enzyme in the biosynthesis of ergot alkaloids to be purified and characterized in homogeneous form after heterologous overproduction.
Cationic antimicrobial peptides elicit a complex stress response in Bacillus subtilis that involves ECF-type sigma factors and two-component signal transduction systems
Authors: Pietiäinen Milla , Gardemeister Marika , Mecklin Maria , Leskelä Soile , Sarvas Matti , Kontinen Vesa P.
Published: May 2005

Stress responses of Bacillus subtilis to membrane-active cationic antimicrobial peptides were studied. Global analysis of gene expression by DNA macroarray showed that peptides at a subinhibitory concentration activated numerous genes. A prominent pattern was the activation of two extracytoplasmic function sigma factor regulons, SigW and SigM. Two natural antimicrobial peptides, LL-37 and PG-1, were weak activators of SigW regulon genes, whereas their synthetic analogue poly-l-lysine was clearly a stronger activator of SigW. It was demonstrated for the first time that LL-37 is a strong and specific activator of the YxdJK two-component systems, one of the three highly homologous two-component systems sensing antimicrobial compounds. YxdJK regulates the expression of the YxdLM ABC transporter. The LiaRS (YvqCE) TCS was also strongly activated by LL-37, but its activation is not LL-37 specific, as was demonstrated by its activation with PG-1 and Triton X-100. Other strongly LL-37-induced genes included yrhH and yhcGHI. Taken together, the responses to cationic antimicrobial peptides revealed highly complex regulatory patterns and induction of several signal transduction pathways. The results suggest significant overlap between different stress regulons and interdependence of signal transduction pathways mediating stress responses.
CAMP factor homologues in Propionibacterium acnes: a new protein family differentially expressed by types I and II
Authors: Valanne Susanna , McDowell Andrew , Ramage Gordon , Tunney Michael M. , Einarsson Gisli G. , O'Hagan Seamus , Wisdom G. Brian , Fairley Derek , Bhatia Ajay , Maisonneuve Jean-Francois , Lodes Michael , Persing David H. , Patrick Sheila
Published: May 2005

Analysis of the draft genome sequence of the opportunistic pathogenPropionibacterium acnestype strain NCTC 737 (=ATCC 6919) revealed five genes with sequence identity to the co-haemolytic Christie–Atkins–Munch-Peterson (CAMP) factor ofStreptococcus agalactiae. The predicted molecular masses for the expressed proteins ranged from 28 to 30 kDa. The genes were present in each of the three recently identifiedrecA-based phylogenetic groupings ofP. acnes(IA, IB and II), as assessed by PCR amplification. Conserved differences in CAMP factor gene sequences between these three groups were also consistent with their previous phylogenetic designations. All type IA, IB and II isolates were positive for the co-haemolytic reaction on sheep blood agar. Immunoblotting and silver staining of SDS-PAGE gels, however, revealed differential protein expression of CAMP factors amongst the different groups. Type IB and II isolates produced an abundance of CAMP factor 1, detectable by specific antibody labelling and silver staining of SDS-PAGE gels. In contrast, abundant CAMP factor production was lacking in type IA isolates, although larger amounts of CAMP factor 2 were detectable by immunoblotting compared with type II isolates. While the potential role of the abundant CAMP factor 1 in host colonization or virulence remains to be determined, it should be noted that the type strain ofP. acnesused in much of the published literature is a type IA isolate and is, therefore, lacking in this attribute.
Characterization of the interaction between subunits of the botulinum toxin complex produced by serotype D through tryptic susceptibility of the isolated components and complex forms
Authors: Suzuki Tomonori , Watanabe Toshihiro , Mutoh Shingo , Hasegawa Kimiko , Kouguchi Hirokazu , Sagane Yoshimasa , Fujinaga Yukako , Oguma Keiji , Ohyama Tohru
Published: May 2005

The 650 kDa large toxin complex (L-TC) produced by Clostridium botulinum serotype D strain 4947 (D-4947) has a subunit structure composed of unnicked components, i.e. neurotoxin (NT), non-toxic non-haemagglutinin (NTNHA) and three haemagglutinin subcomponents (HA-70, HA-33 and HA-17). In this study, subunit interactions were investigated through the susceptibilities of the toxin components to limited trypsin proteolysis. Additionally, complex forms were reconstituted in vitro by various combinations of individual components. Trypsin treatment of intact D-4947 L-TC led to the formation of mature L-TC with nicks at specific sites of each component, which is usually observed in other strains of serotype D. NT, NTNHA and HA-17 were cleaved at their specific sites in either the single or complex forms, but HA-33 showed no sign of proteolysis. Unlike the other components, HA-70 was digested into random fragments as a single form, but it was cleaved into two fragments in the complex form. Based on the relative position of exposed or hidden regions of the individual components in the complex derived from their tryptic susceptibilities, an assembly model is proposed for the arrangement of individual subunits in the botulinum L-TC.
mrpA, a gene with roles in resistance to Na+ and adaptation to alkaline pH in the cyanobacterium Anabaena sp. PCC7120
Authors: Blanco-Rivero A. , Leganés F. , Fernández-Valiente E. , Calle P. , Fernández-Piñas F.
Published: May 2005

Transposon mutagenesis ofAnabaenasp. PCC7120 led to the isolation of a mutant strain, PHB11, which grew poorly at pH values above 10. The mutant strain exhibited pronounced Na+sensitivity; this sensitivity was higher under basic conditions. Mutant PHB11 also showed an inhibition of photosynthesis that was much more pronounced at alkaline pH. Reconstruction of the transposon mutation of PHB11 in the wild-type strain reproduced the phenotype of the original mutant. The wild-type version of the mutated gene was cloned and the mutation complemented. In mutant strain PHB11, the transposon had inserted within an ORF that is part of a seven-ORF operon with significant sequence similarity to a family of bacterial operons that are believed to code for a novel multiprotein cation/proton antiporter primarily involved in resistance to salt stress and adaptation to alkaline pH. TheAnabaenaoperon was denotedmrp(multiple resistance and pH adaptation) following the nomenclature of theBacillus subtilisoperon; the ORF mutated in PHB11 corresponded tomrpA. Computer analysis suggested that all seven predictedAnabaenaMrp proteins were highly hydrophobic with several transmembrane domains; in fact, the predicted protein sequences encoded bymrpA,mrpBandmrpCshowed significant similarity to hydrophobic subunits of the proton pumping NADH : ubiquinone oxidoreductase.In vivoexpression studies indicated thatmrpAis induced with increasing external Na+concentrations and alkaline pH;mrpAis also upregulated under inorganic carbon (Ci) limitation. The biological significance of a putative cyanobacterial Mrp complex is discussed.
The dimorphic yeast Yarrowia lipolytica possesses an atypical phosphofructokinase: characterization of the enzyme and its encoding gene
Authors: Flores Carmen-Lisset , Martínez-Costa Oscar H. , Sánchez Valentina , Gancedo Carlos , Aragón Juan J.
Published: May 2005

The phosphofructokinase from the non-conventional yeastYarrowia lipolytica(YlPfk) was purified to homogeneity, and its encoding gene isolated. YlPfk is an octamer of 869 kDa composed of a single type of subunit, and shows atypical kinetic characteristics. It did not exhibit cooperative kinetics for fructose 6-phosphate (Hill coefficient,h1·1;S0·552 μM), it was inhibited moderately by MgATP (Ki3·5 mM), and it was strongly inhibited by phosphoenolpyruvate (Ki61 μM). Fructose 2,6-bisphosphate did not activate the enzyme, and AMP and ADP were also without effect. The geneYlPFK1has no introns, and encodes a putative protein of 953 aa, with a molecular mass consistent with the subunit size found after purification. Disruption of the gene abolished growth in glucose and Pfk activity, while reintroduction of the gene restored both properties. This indicates thatY. lipolyticahas only one gene encoding Pfk, and supports the finding that the enzyme consists of identical subunits. Glucose did not interfere with growth of theYlpfk1disruptant in permissive carbon sources. The unusual kinetic characteristics of YlPfk, and the intracellular concentrations of glycolytic intermediates during growth in glucose, suggest that YlPfk may play an important role in the regulation of glucose metabolism inY. lipolytica, different from the role played by the enzyme inSaccharomyces cerevisiae.
Characterization of Malignant Melanoma Using Vibrational Spectroscopy
Authors: Hammody Ziad , Sahu Ranjit Kumar , Mordechai Shaul , Cagnano Emanuela , Argov Shmuel
Published: May 2005

Malignant melanoma, a malignant neoplasm of epidermal melanocytes is the third most common skin cancer. In many cases, melanoma develops from nevus, which is considered as the nonmalignant stage. Fourier transform infrared microspectroscopy (FTIR-MSP), which is based on characteristic molecular vibrational spectra of cells, was used to investigate spectral differences between melanoma, nevus, and the corresponding normal epidermis. In the present work, FTIR-MSP was performed on formalin-fixed biopsies of melanoma and nevi along with the adjoining histologically normal epidermis to understand the biochemical variations from the epidermis and identify suitable parameters for differentiation of nevi from melanoma. The comparative analysis of various parameters calculated from the spectral data of the normal epidermis and the abnormal regions showed that the changes in the nucleic acids was a significant indicator of the abnormal nature of the tissues. The RNA/DNA ratio was decreased in case of both melanoma and nevus compared to the epidermis. The amide II/amide I ratio was greater for nevus and melanoma compared to the epidermis. In contrast to other organs, the analysis of carbohydrates was not found as a suitable indicator in case of malignant melanoma. Shifts in band wave number were found to be a major distinguishing feature between the melanoma and compound nevi. The present study helps in the identification of spectral features suitable for distinction of melanoma from nevus that appear similar even in FTIR spectral features and thus can pave the way for development ofin vivoscreening systems based on these diagnostic markers.
An Alternative to Null-Hypothesis Significance Tests
Authors: Killeen Peter R.
Published: May 2005

The statistic Prep estimates the probability of replicating an effect. It captures traditional publication criteria for signal-to-noise ratio, while avoiding parametric inference and the resulting Bayesian dilemma. In concert with effect size and replication intervals, Prep provides all of the information now used in evaluating research, while avoiding many of the pitfalls of traditional statistical inference.
Deciding to Defect
Authors: Sheese Brad E. , Graziano William G.
Published: May 2005

This experiment examined the effect of videogame violence on cooperative decision making. Participants (N = 48) were randomly assigned to play either a violent or a nonviolent version of the video game Doom™ in dyads. Following the video-game task, participants were separated and given an opportunity to choose to cooperate with their partner for mutual gain, withdraw from the interaction, or exploit their partner for their own benefit. Participants in the violent condition were significantly more likely to choose to exploit their partners than participants in the nonviolent condition. These findings suggest that playing violent video games may undermine prosocial motivation and promote exploitive behavior in social interactions.
Gesture Paves the Way for Language Development
Authors: Iverson Jana M. , Goldin-Meadow Susan
Published: May 2005

In development, children often use gesture to communicate before they use words. The question is whether these gestures merely precede language development or are fundamentally tied to it. We examined 10 children making the transition from single words to two-word combinations and found that gesture had a tight relation to the children's lexical and syntactic development. First, a great many of the lexical items that each child produced initially in gesture later moved to that child's verbal lexicon. Second, children who were first to produce gesture-plus-word combinations conveying two elements in a proposition (point at bird and say “nap”) were also first to produce two-word combinations (“bird nap”). Changes in gesture thus not only predate but also predict changes in language, suggesting that early gesture may be paving the way for future developments in language.
Labeling Guides Object Individuation in 12-Month-Old Infants
Authors: Xu Fei , Cote Melissa , Baker Allison
Published: May 2005

A new manual search method was used to investigate the impact of naming on object individuation in 12-month-old infants. In Experiment 1, on a two-word trial, an experimenter looked into a box while the infant was watching and provided two labels (e.g., “Look, a fep!” and “Look, a wug!”). On a one-word trial, the experimenter instead repeated the same label (e.g., “Look, a zav!”). After the infant retrieved one object from the box, subsequent search behavior was recorded. Infants searched more persistently (i.e., for a longer duration) after hearing two labels than one, suggesting that hearing two labels led the infants to expect two objects inside the box. In Experiment 2, infants' search behavior did not differ depending on whether they heard one or two emotional expressions, suggesting that the facilitation effect observed in Experiment 1 may be specific to linguistic expressions. Thus, we provide the first evidence that infants as young as 12 months are able to use intentional and referential cues to guide their object representations. These findings also suggest that a rudimentary version of the mutual-exclusivity constraint may be functional by the end of the first year.
You Can't Always Get What You Want
Authors: Kieras Jessica E. , Tobin Renée M. , Graziano William G. , Rothbart Mary K.
Published: May 2005

This study examined individual differences in children's regulation of emotional expression after receiving desirable and undesirable gifts. Effortful control, the ability to suppress a dominant response in favor of a subdominant one, was measured using a battery of behavioral tasks. Reactions to the gifts were videotaped, and emotional expression was coded. Age predicted effortful control, but not emotional displays. Effortful control predicted similarity of children's displays of positive affect after receiving the two gifts. Specifically, children high in effortful control showed similar amounts of positive affect after receiving the desirable and undesirable gifts, whereas children low in effortful control showed less positive affect after receiving the undesirable gift than after receiving the desirable gift. Results are discussed in terms of temperament and the development of socially appropriate expressive behavior.
Ironic Effects of Racial Bias During Interracial Interactions
Authors: Shelton J. Nicole , Richeson Jennifer A. , Salvatore Jessica , Trawalter Sophie
Published: May 2005

Previous research has suggested that Blacks like White interaction partners who make an effort to appear unbiased more than those who do not. We tested the hypothesis that, ironically, Blacks perceive White interaction partners who are more racially biased more positively than less biased White partners, primarily because the former group must make more of an effort to control racial bias than the latter. White participants in this study completed the Implicit Association Test (IAT) as a measure of racial bias and then discussed race relations with either a White or a Black partner. Whites' IAT scores predicted how positively they were perceived by Black (but not White) interaction partners, and this relationship was mediated by Blacks' perceptions of how engaged the White participants were during the interaction. We discuss implications of the finding that Blacks may, ironically, prefer to interact with highly racially biased Whites, at least in short interactions.
Deciphering the Enigmatic Face
Authors: Ambadar Zara , Schooler Jonathan W. , Cohn Jeffrey F.
Published: May 2005

Most studies investigating the recognition of facial expressions have focused on static displays of intense expressions. Consequently, researchers may have underestimated the importance of motion in deciphering the subtle expressions that permeate real-life situations. In two experiments, we examined the effect of motion on perception of subtle facial expressions and tested the hypotheses that motion improves affect judgment by (a) providing denser sampling of expressions, (b) providing dynamic information, (c) facilitating configural processing, and (d) enhancing the perception of change. Participants viewed faces depicting subtle facial expressions in four modes (single-static, multi-static, dynamic, and first-last). Experiment 1 demonstrated a robust effect of motion and suggested that this effect was due to the dynamic property of the expression. Experiment 2 showed that the beneficial effect of motion may be due more specifically to its role in perception of change. Together, these experiments demonstrated the importance of motion in identifying subtle facial expressions.
Inter‐calibration of three electric fishing techniques to estimate 0+ juvenile fish densities on sandy river beaches
Authors: JANÁČ M. , JURAJDA P.
Published: May 2005

Abstract  The efficiencies of three different techniques for 0+ fish point abundance sampling by electric fishing were tested on a sandy beach of the Morava River, Czech Republic. During direct electric fishing (DE), the operator immerses an anode fastened on an extension pole. During thrown anode electric fishing (TE), the anode is thrown at a distance from the bank. During remote electric fishing (RE), a pre‐positioned anode is activated after allowing sufficient time for fish to recolonise the area. The DE technique was found to disturb fish and that fish tend to escape, thereby reducing its efficiency (30% of efficiency of RE). There was no significant difference in relative abundance estimates or size structure of assemblages between DE and RE, but TE seemed to be a species selective technique on sandy river beaches, significantly overestimating relative abundance of bleak. Of the three techniques tested, RE was the most efficient and if time required for deployment could be reduced, it would be also the most suitable for monitoring 0+ fish assemblages on sandy river beaches.
Distribution and biomass of an underfished vendace, Coregonus albula, population in a mesotrophic German reservoir
Authors: SCHMIDT M. B. , GASSNER H. , MEYER E. I.
Published: May 2005

Abstract  The distribution and overall biomass of an underfished vendace, Coregonus albula L., population in the mesotrophic Henne Reservoir (Germany) was studied using hydroacoustics and gill nets. Additionally, midwater trawling was carried out. Overall fish biomass, based on five hydroacoustic surveys (June to September 2002), ranged from 188 kg ha−1 in early August to 302 kg ha−1 in September 2002. The overall mean fish biomass was 256 kg ha−1 (±48 kg ha−1 SD). Biomass of fish smaller than 25 cm total length (mostly vendace) varied from 56 kg ha−1 in August to 99 kg ha−1 in September, with an overall mean fish biomass of 74 kg ha−1 (±17 kg ha−1 SD). The echograms showed temporal variation in fish distribution in Henne Reservoir. In June, fish were fairly evenly distributed over the whole reservoir but in September a dense aggregation of fish (mostly vendace) was found in the deeper water layers near the dam. The distribution of vendace stock, its impact on water quality and fisheries management, biomanipulation and effort for mass removal are discussed.
Association between biogeographical factors and boreal lake fish assemblages
Authors: VAN ZYLL DE JONG M. C. , COWX I. G. , SCRUTON D. A.
Published: May 2005

Abstract  Five regions in insular Newfoundland Canada, comprising 152 lakes, were studied to identify associations between species composition (presence and absence), geographical location and environmental variables (pH, area, depth, alkalinity, secchi disc depth and shoreline development factor). Correspondence analysis and canonical variate analysis were used to distinguish regional patterns. Five biologically and environmentally distinct areas were identified. The degree of association between biological, environmental and geographical distances were contrasted using Mantel's test. Regional fish community structure was significantly correlated with large‐scale geographical distance but not with environmental parameters or small scale distance. It was proposed that large scale processes such as post‐glacial dispersion, climate and recent species introductions are important determinates in structuring regional fish assemblages. Differences in individual lake character were important determinates in intraregional variability in fish assemblage type. Sampling strategies for regional modelling and management are discussed.
The life history of Tenualosa macrura in Sarawak, further notes on protandry in the genus and management strategies
Authors: BLABER S. J. M. , FRY G. , MILTON D.A. , VAN DER VELDE T. , BOON‐TECK O. , PANG J. , WONG P.
Published: May 2005

Abstract  The contraction of Tenualosa macrura (Bleeker) to the Sarawak coast and a small part of Sumatra, and the decline in its fishery mirror what has happened to three other species in the genus. Little was known of this species in its last stronghold in Sarawak where it is important for management and conservation reasons to understand its biology and life history. It forms part of a multispecies fishery where effort is uniform, but catches follow a lunar cycle. Tenualosa macrura is protandrous, but low numbers of small females suggest diandry. In Sumatra Tenualosa macrura spawn throughout the year, but in Sarawak have a seasonal peak in the NE monsoon (December). This has management implications because the Sarawak fishery ceases at this time because of adverse weather, hence reducing fishing pressure on spawning T. macrura. Management measures introduced in Sarawak for Tenualosa toli (Valenciennes) may therefore not be required for T. macrura.
Measures of surgical quality: what will patients know by 2005?
Authors: Broder Michael S. , Payne‐Simon Lisa , Brook Robert H.
Published: May 2005

Rationale, aims and objectives  Many objective measures rating quality of doctors, hospitals, and medical groups are publicly reported. Surgical patients may have more opportunity to use quality measures than other types of patients to guide their choice of provider. If surgical patients are able to choose higher quality providers, overall surgical quality might increase.

Objective  To determine what procedure‐specific measures of surgical quality are available to consumers facing surgery in California and what  new  measures  will  be  available  by  2005. 

Methods  We searched for and surveyed organizations publicly reporting data on health care quality in California. We asked about current quality measures and new measures set for public release by 2005. Included measures had to be procedure‐specific and results separated by hospital. The main outcome measures were the number of quality measures; conceptual aspect of quality measured; and type of risk‐adjustment used.

Results  Eighteen organizations publicly report any health care quality measures in California. These organizations report 333 measures, of which 32 (10%) are procedure‐specific measures of surgical quality. There is at least one quality measure for 21 different procedures; these procedures account for 14% of all major operations. Three new  measures  will  be  released  by 2005.

Conclusions  Californians facing surgery have limited information regarding quality of their care; few new measures are planned. Eighty‐six per cent of patients would find no quality measures related to planned procedures. Public release of performance data is unlikely to improve the quality of health care unless the number and comprehensiveness of measures increase dramatically.
Evaluation of the Personal Dental Services (Wave 1) for Lambeth, Southwark and Lewisham Primary Care Trusts – Part 1: Retrospective analyses of registration data and access issues
Authors: Best Helen , Newton Tim
Published: May 2005

Aim/objective  The purpose of the study was to undertake analyses of registration data for the personal dental services (PDS) of Lambeth, Southwark and Lewisham primary care trusts and relate the analyses to the PDS goal  of  increasing  uptake  of  dental services.

Method  Secondary analyses of registration statistics provided by the Dental Practice Board were undertaken for both 1 years pre‐PDS (October 1997 to September 1998) and post‐PDS (October 1998 to March 2003) periods. Three sets of analyses were undertaken to consider different aspects of changing registrations: (1) Absolute numbers of patients registered at each time interval; (2) Rates of change in numbers of patients registered for the entire period after the introduction of PDS; and (3) Rates of change in numbers of patients registered  for  the  most recent 3 years of available data.

Results  There was a significant increase in the numbers of children registered under capitation, post‐PDS as compared to the pre‐PDS level (all ages and both genders combined). Post‐PDS, the rate of increase for the children was approximately one additional child per practice per month (0.96, 95% CI 0.41–1.52). Similarly there was a significant trend for increasing adults registrations over time of about two and a half adults per practice per month (2.42, 95% CI 0.90–3.95). There was no evidence of a change in registrations for children or adults in total over the most recent period of 3 years.

Conclusions  The analysis of the absolute numbers of registered patients each month indicated that the PDS practices had more children registered than before the implementation of the PDS scheme, but not adults. Overall post‐implementation there was a trend for increasing registrations in both children and adults, but the most recent data indicated a plateau effect. Further consideration of facilitators to achieve PDS goals of improved uptake of services is required, particularly as they relate to local contexts.
Impact of a community pharmacist‐directed clinic in improving screening and awareness of osteoporosis
Authors: Law Anandi V. , Shapiro Karen
Published: May 2005

Rationale, aims and objectives  There is a need to increase screening and awareness of osteoporosis risk in order to prevent fractures and related morbidity. Although one in two women are at risk of developing the condition, only one in five receives bone mineral density screening. The purpose of the current study was to investigate the effectiveness of an osteoporosis screening and awareness programme directed by a pharmacist in the community setting.

Methods  The study design to test for improved awareness was a prospective, pre–post trial with no control group. The level of awareness of risk was assessed both before the screening and following an educational intervention on osteoporosis provided in the pharmacy. Based on assessed risk level, a recommendation was made for follow‐up with a doctor for a dual‐energy X‐ray absorptiometry (DEXA) scan and/or pharmacotherapy. Patients at medium or high risk were also surveyed as to their intention to follow‐up with lifestyle modification recommendations.

Results  There was a significant improvement in tested awareness from pre‐ to post‐intervention at 26%; as well in self‐rated awareness. There was also a significant correlation between self‐rated and tested awareness. Participants indicated satisfaction with the pharmacist interaction and with their role in improving awareness. A large percentage of participants indicated that they intended to follow‐up with the pharmacist's recommendation for calcium intake,  exercise  and/or consulting  with their doctor. 

Conclusion  The results indicate that the community pharmacist can successfully screen individuals for risk of osteoporosis and improve their awareness about steps to prevent or delay fractures.