bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation and differential expression of gdhA encoding NADP‐specific glutamate dehydrogenase in Neisseria meningitidis clinical isolates
Authors: Pagliarulo Caterina , Salvatore Paola , De Vitis Lucia Rosaria , Colicchio Roberta , Monaco Caterina , Tredici Maurizio , Talà Adelfia , Bardaro Marcellino , Lavitola Alfredo , Bruni Carmelo B. , Alifano Pietro 
Published: December 2004

SummaryMeningococcal gdhA, encoding the NADP‐specific l‐glutamate dehydrogenase (NADP‐GDH), is essential for systemic infection in an infant rat model. In this paper, a limited transcriptional analysis detected differences in gdhA expression among clinical isolates. In strains expressing high levels of gdhA mRNA, two promoters, gdhA P1 and gdhA P2, initiated transcription of gdhA. In contrast, in strains expressing low mRNA levels, gdhA P2 was not active because of weak expression of gdhR, an associated regulatory gene. Gene knock‐out and complementation of a gdhR‐defective mutant confirmed that GdhR is a positive regulator for gdhA P2. Trans‐activation of gdhA P2 was maximal in complex medium during late logarithmic growth phase and in chemical defined medium (MCDA) when glucose (MCDA‐glucose) instead of lactate (MCDA‐lactate) was used as a carbon source in the presence of glutamate. gdhR knock‐out mutants lost both growth phase and carbon source regulation, and exhibited a growth defect more severe in MCDA‐glucose than in MCDA‐lactate. DNA–protein interaction studies demonstrated that 2‐oxoglutarate, a product of the catabolic reaction of the NADP‐GDH and an intermediate of the tricarboxylic acid (TCA) cycle, inhibits binding of GdhR to gdhA P2.
The Sup35 domains required for maintenance of weak, strong or undifferentiated yeast [PSI+] prions
Authors: Bradley Michael E. , Liebman Susan W. 
Published: December 2004

SummaryThe Sup35 protein can exist in a non‐infectious form or in various infectious forms called [PSI+] prion variants (or prion strains). Each of the different [PSI+] prion variants converts non‐infectious Sup35 molecules into that prion variant's infectious form. One definition of a ‘prion domain’ is the minimal fragment of a prion protein that is necessary and sufficient to maintain the prion form. We now demonstrate that the Sup35 N region (residues 1–123), which is frequently referred to as the ‘prion domain’, is insufficient to maintain the weak or strong [PSI +] variants per se, but appears to maintain them in an ‘undifferentiated’[PSI+] state that can differentiate into weak or strong [PSI+] variants when transferred to the full‐length Sup35 protein. In contrast, Sup35 residues 1–137 are necessary and sufficient to faithfully maintain weak or strong [PSI+] variants. This implicates Sup35 residues 124–137 in the variant‐specific maintenance of the weak or strong [PSI+] forms. Structure predictions indicate that the residues in the 124–137 region form an α‐helix and that the 1–123 region may have β structure. In view of these findings, we discuss a plausible molecular basis for the [PSI+] prion variants as well as the inherent difficulties in defining a ‘prion domain’.
Involvement of two domains with helix–turn–helix and zinc finger motifs in the binding of IS1 transposase to terminal inverted repeats
Authors: Ohta Shinya , Yoshimura Etsuro , Ohtsubo Eiichi 
Published: December 2004

SummaryThe insertion element IS1 has two open reading frames (ORFs), insA and insB, and produces a transframe protein InsAB, known as IS1 transposase, by translational frameshifting. The transposase binds to terminal inverted repeats (IRL and IRR) to promote IS1 transposition. Unless frameshifting occurs, IS1 produces InsA protein, which also binds to IRs and therefore acts as an inhibitor of transposition, as well as a transcriptional repressor of the promoter in IRL. A helix–turn–helix (HTH) motif present in both transposase and InsA is thought to be involved in IR‐specific DNA binding. A comparison of transposases encoded by IS1 family elements reveals that the N‐terminal regions contain four conserved cysteine residues, which appear to constitute a C2C2 zinc finger (ZF) motif. This motif is also thought to be involved in IR‐specific DNA binding. In this study, we show that IS1 transposases with an amino acid substitution in the HTH or ZF motif lose the ability to promote transposition. We also show that transposases, as well as InsA proteins with the same substitution, lose the ability to repress the activity of the IRL promoter, and that purified InsA mutant proteins lose the ability to bind to the IRL‐containing fragment. Furthermore, we show that InsA protein co‐ordinates Zn(II) with the four cysteine residues as ligands and loses the ability to bind to the IRL‐containing fragment in the presence of an agent chelating Zn(II). These findings indicate that IS1 transposase has two domains with HTH and ZF motifs responsible for IR‐specific DNA binding in promoting transposition. It is assumed that the two domains are needed for transposase to bind to each IR in an oriented manner in order to place a catalytic domain in the C‐terminal region of the transposase to a region around the IR end, where the strand transfer reaction occurs in a transpososome.
The role of Par proteins in the active segregation of the P1 plasmid
Authors: Li Yongfang , Dabrazhynetskaya Alena , Youngren Brenda , Austin Stuart 
Published: December 2004

SummaryThe parS centromere‐like site promotes active P1 plasmid segregation in the presence of P1 ParA and ParB proteins. At the modest growth rate used here, time‐lapse and still photomicroscopy shows that the plasmid copies are clustered as a focus at the Escherichia coli cell centre. Just before cell division, the focus is actively divided and ejects bidirectionally into opposite halves of the dividing cell. In the absence of the wild‐type parS binding protein ParB, a focus was formed, but generally did not go to the cell centre. The randomly placed focus did not divide and was inherited by one daughter cell only. In the absence of ParA, foci formed and frequently fixed to the cell centre. However, they failed to divide or eject and were left at the new cell pole of one cell at division. Thus, ParB appears to be required for recognition of the plasmid and its attachment to the cell centre, and ParA is required for focus division and energetic ejection from the cell centre. The ATPase active site mutation, parAK122E, blocked ejection. Mutant parAM314I ejected weakly, and the daughter foci took two generations to reach a new cell centre. This explains the novel alternation of segregation and missegregation in successive generations seen in time‐lapse images of this mutant.
The accumulation of deleterious mutations within the frozen niche variation hypothesis
Authors: Pound G. E. , Cox S. J. , Doncaster C. P. 
Published: December 2004

Abstract
The frozen niche variation hypothesis proposes that asexual clones exploit a fraction of a total resource niche available to the sexual population from which they arise. Differences in niche breadth may allow a period of coexistence between a sexual population and the faster reproducing asexual clones. Here, we model the longer term threat to the persistence of the sexual population from an accumulation of clonal diversity, balanced by the cost to the asexual population resulting from a faster rate of accumulation of deleterious mutations. We use Monte-Carlo simulations to quantify the interaction of niche breadth with accumulating deleterious mutations. These two mechanisms may act synergistically to prevent the extinction of the sexual population, given: (1) sufficient genetic variation, and consequently niche breadth, in the sexual population; (2) a relatively slow rate of accumulation of genetic diversity in the clonal population; (3) synergistic epistasis in the accumulation of deleterious mutations.
Sexual selection on morphological and physiological traits and fluctuating asymmetry in the black scavenger fly Sepsis cynipsea
Authors: Blanckenhorn W. U. , Kraushaar U. R. S. , Teuschl Y. , Reim C. 
Published: December 2004

Abstract
Previous univariate studies of the fly Sepsis cynipsea (Diptera: Sepsidae) have demonstrated spatiotemporally variable and consequently overall weak sexual selection favouring large male size, which is nevertheless stronger on average than fecundity selection favouring larger females. To identify specific target(s) of selection on body size and additional traits possibly affecting mating success, two multivariate field studies of sexual selection were conducted. In one study using seasonal replicates from three populations, we assessed 15 morphological traits. No clear targets of sexual selection on male size could be detected, perhaps because spatiotemporal variation in selection was again strong. In particular, there was no (current) selection on male abdomen length or fore coxa length, the only traits for which S. cynipsea males are not smaller than females. Interestingly, copulating males had a consistently shorter fore femur base, a secondary sexual trait, and a wider clasper (hypopygium) gap, an external genital trait. In a second study using daily and seasonal replicates from one population, we included physiological measures of energy reserves (lipids, glucose, glycogen), in addition to hind tibia length and fluctuating asymmetry (FA) of all pairs of legs. This study again confirmed the mating advantage of large males, and additionally suggests independent positive influences of lipids (the long-term energy stores), with effects of glucose and glycogen (the short-term energy stores) tending to be negative. FA of paired traits was not associated with male mating success. Our study suggests that inclusion of physiological measures and genital traits in phenomenological studies of selection, which is rare, would be fruitful in other species.
The role of complement in invasive fungal infections
Authors: Speth Cornelia , Rambach Günter , Lass‐Flörl Cornelia , Dierich Manfred P. , Würzner Reinhard 
Published: December 2004

SummaryNew therapeutic approaches enable organ transplantations and guarantee longer survival for AIDS patients or patients with haematological neoplasia. The price for these medical advances is immunosuppression and thus enhanced susceptibility to opportunistic fungal infections. As a consequence invasive fungal infections are on the march in modern medicine. Therapeutic limitations and difficulties strongly demand for a deeper understanding of the interaction between the various fungi and the hosts’ innate and adaptive immune defence system. This understanding is the essential prerequisite for a potential therapeutic approach, which may support specifically the insufficient antifungal attack of the host. In the present article, we therefore review the current knowledge of the role of the complement system as a central part of innate immunity and as a fine tuner of adaptive immunity in the pathogenesis of invasive fungal infections, such as aspergillosis, candidosis, cryptococcosis, paracoccidioidomycosis, blastomycosis and histoplasmosis.
Outpatients undergoing therapeutic endoscopic retrograde cholangiopancreatography: Six‐hour versus overnight observation
Authors: HUI CHEE‐KIN , LAI KAM‐CHUEN , WONG WAI‐MAN , YUEN MAN‐FUNG , NG MATTHEW , CHAN CHI‐KUEN , HU WAYNE , CHEUNG WINNIE W , LAI CHING‐LUNG , WONG BENJAMIN CY 
Published: December 2004

AbstractBackground and Aim:  The purpose of the present retrospective study was to compare the proportion of post‐endoscopic retrograde cholangiopancreatography (ERCP) complications detected with 6‐h observation followed by same‐day discharge (SDD) versus overnight observation (OO) after therapeutic ERCP.Methods:  There were 134 outpatients in the SDD group and 178 outpatients in the OO group. The SDD group was discharged after a 6‐h observation while the OO group was discharged after overnight observation. Patients in the SDD group were admitted from the recovery room for evaluation if they had systolic blood pressure (BP) < 100 mmHg, pulse > 100/min, temperature > 37.5°C, or post‐procedure abdominal pain. The primary outcome of the present study was the proportion of post‐ERCP complications detected within the observational period between the SDD group and the OO group.Results:  The post‐ERCP complication rate of therapeutic ERCP in the SDD and OO groups were 9.7% and 9.6%, respectively (P = 0.964). Eleven patients (8.2%) in the SDD group and 13 patients (7.3%) in the OO group were found to have post‐ERCP complications within the observation period. There was no significant difference in the proportion of post‐ERCP complications detected within the observational period between the two groups (P = 0.672).Conclusion:  Outpatient therapeutic ERCP with observation of 6 h can detect the same proportion of patients with post‐ERCP complications as overnight observation.© 2004 Blackwell Publishing Asia Pty Ltd
The influence of children on parental purchases during supermarket shopping
Authors: Wilson George , Wood Katie 
Published: December 2004

AbstractChildren are assuming larger roles in household consumer decisions and have also emerged as independent consumers, thus forming an increasingly powerful market segment. Children can be seen as forming, first, a primary market; second, as influencers on their parents’ decision making; and third, as potential future adult consumers. The second role is the main focus of this paper, centring on supermarket purchases. Using focus groups and in‐depth interviews, this study explores the influence of children on supermarket shopping. Participants included parents and children of families in Midlothian, Scotland. The results showed that children have a significant influence on supermarket product purchases. The factors which influence children's product preferences are analysed, and their ability to relay their choices to their parents is considered.
Electronic shopping: young people as consumers
Authors: Ige Olalonpe 
Published: December 2004

AbstractFindings and discussions in this paper lead to recommendations in relation to young people as consumers in the electronic marketplace. The recommendations in this paper may be of value to students, academics, e‐marketers and e‐retailers. This paper seeks to take a cross‐border perspective while discussing the issue of young consumers and electronic shopping. It attempts to discuss significant macro‐environmental influences on young consumers in the electronic commerce market. It also highlights important opportunities and threats, relevant to the young consumers target market. The paper finally introduces generic strategies that may be used to successfully target the youth market and discusses resulting implications. Before delving into the electronic shopping market analysis and the strategic focus on young people, the paper will first introduce the meaning of electronic shopping and highlight the interdependent nature of electronic shopping and e‐commerce. It will also explain what is meant by young consumers in the context of this study.
Enhancing the MeSH thesaurus to retrieve French online health resources in a quality‐controlled gateway
Authors: Douyère Magaly , Soualmia Lina F. , Névéol Aurélie , Rogozan Alexandrina , Dahamna Badisse , Leroy Jean‐Philippe , Thirion Benoît , Darmoni Stefan J. 
Published: December 2004

AbstractThe amount of health information available on the Internet is considerable. In this context, several health gateways have been developed. Among them, CISMeF (Catalogue and Index of Health Resources in French) was designed to catalogue and index health resources in French. The goal of this article is to describe the various enhancements to the MeSH thesaurus developed by the CISMeF team to adapt this terminology to the broader field of health Internet resources instead of scientific articles for the medline bibliographic database. CISMeF uses two standard tools for organizing information: the MeSH thesaurus and several metadata element sets, in particular the Dublin Core metadata format. The heterogeneity of Internet health resources led the CISMeF team to enhance the MeSH thesaurus with the introduction of two new concepts, respectively, resource types and metaterms. CISMeF resource types are a generalization of the publication types of medline. A resource type describes the nature of the resource and MeSH keyword/qualifier pairs describe the subject of the resource. A metaterm is generally a medical specialty or a biological science, which has semantic links with one or more MeSH keywords, qualifiers and resource types. The CISMeF terminology is exploited for several tasks: resource indexing performed manually, resource categorization performed automatically, visualization and navigation through the concept hierarchies and information retrieval using the Doc’CISMeF search engine. The CISMeF health gateway uses several MeSH thesaurus enhancements to optimize information retrieval, hierarchy navigation and automatic indexing.
Developing methods for systematic reviewing in health services delivery and organization: an example from a review of access to health care for people with learning disabilities. Part 2. Evaluation of the literature—a practical guide
Authors: Alborz Alison , McNally Rosalind 
Published: December 2004

AbstractObjectives:  To develop methods to facilitate the ‘systematic’ review of evidence from a range of methodologies on diffuse or ‘soft’ topics, as exemplified by ‘access to health care’.Data sources:  Twenty‐eight bibliographic databases, research registers, organizational websites or library catalogues. Reference lists from identified studies. Contact with experts and service users. Current awareness and contents alerting services in the area of learning disabilities.Review methods:  Inclusion criteria were English language literature from 1980 onwards, relating to people with learning disabilities of any age and all study designs. The main criteria for assessment was relevance to Guillifords’ model of access to health care which was adapted to the circumstances of people with learning disabilities. Selected studies were evaluated for scientific rigour then data was extracted and the results synthesized. Quality assessment was by an initial set of ‘generic’ quality indicators. This enabled further evidence selection before evaluation of findings according to specific criteria for qualitative, quantitative or mixed‐method studies.Results:  Eighty‐two studies were fully evaluated. Five studies were rated ‘highly rigorous’, 22 ‘rigorous’, 46 ‘less rigorous’ and nine ‘poor’ papers were retained as the sole evidence covering aspects of the guiding model. The majority of studies were quantitative but used only descriptive statistics. Most evidence lacked methodological detail, which often lowered final quality ratings.Conclusions:  The application of a consistent structure to quality evaluation can facilitate data appraisal, extraction and synthesis across a range of methodologies in diffuse or ‘soft’ topics. Synthesis can be facilitated further by using software, such as the microsoft ‘access’ database, for managing information.
Life‐history of two African Sylvia warblers: low annual fecundity and long post‐fledging care
Authors: Schaefer Hans‐Christian , Eshiamwata George W. , Munyekenye Fred B. , Böhning‐Gaese Katrin 
Published: December 2004

The investigation of factors that cause differences in life‐history traits between temperate and tropical birds is often hampered by a lack of knowledge about tropical species. Even within the well‐known warblers of the genus Sylvia, which include resident species from temperate and tropical regions as well as migrants, there are few data from tropical species. We investigated the breeding biology of the tropical species Sylvia lugens and S. boehmi in a 2‐year study in Kenya. Both species had a clutch size of 2.0 and laid c. 3.7 clutches per year. Breeding was characterized by long incubation periods (S. lugens 14.5 days, S. boehmi 15.0 days), long nestling periods (16.0 and 12.9 days, respectively) and high predation rates (Mayfield nest success S. lugens 33.2%, S. boehmi 19.4%). Annual fecundity was 2.3 fledglings in S. lugens and 1.4 fledglings in S. boehmi. After fledging, the young birds were fed for 37.5 days (S. lugens) and 58.5 days (S. boehmi) (time to independence) and they stayed in their parents’ territory for days or weeks, even after feeding had stopped. Fledgling survival until independence was 55.4% in S. lugens and 69.2% in S. boehmi. In general, S. lugens and S. boehmi have smaller but more numerous clutches, longer developmental periods, higher nest predation rates, lower annual fecundity and longer post‐fledging care than their temperate congenerics.
A mathematical model of factors that influence the performance of accommodative intraocular lenses
Authors: Heatley C. J. , Spalton D. J. , Boyce J. F. , Marshall J. 
Published: December 2004

AbstractIn this work a mathematical model of capsule movement during pseudophakic accommodation is described to allow identification and evaluation of factors that may explain the variation in effect of accommodative intraocular lenses (IOLs) between patients. The model assumes that increasing vitreous pressure pushes the lens capsule forward as a circular diaphragm and that this movement is from a fixed fulcrum. With an IOL in situ, the capsule is taken to have a non‐uniform thickness due to the presence of the anterior capsulorhexis. The model assumes a uniform capsular elasticity and ignores contributions from cellular elements such as posterior capsule opacification. Using our model and a regression formula to calculate capsular bag size, taking into account axial length and keratometry values, we are able to predict accommodative effect in individual patients. By simple geometry we have developed a mathematical model to identify variables that are important in pseudophakic accommodation. It provides the basis for the development of a more complex model that would address the movement of a lens taking into account the influence of the zonular system during accommodation.
Subjective Memory Complaints and Objective Memory Impairment in the Vienna‐Transdanube Aging Community
Authors: Jungwirth Susanne , Fischer Peter , Weissgram Silvia , Kirchmeyr Walter , Bauer Peter , Tragl Karl‐Heinz 
Published: December 2004

Objectives: To help answer the question of whether subjective memory complaints are a useful feature in classification systems addressing early stages of Alzheimer's disease.Design: A cross‐sectional investigation in the context of a community‐based cohort study.Setting: Vienna, Transdanube—a geographically defined, urban, working‐class area.Participants: Three hundred two nondemented 75‐year‐olds were examined with regard to subjective memory complaints and objective memory performance. The patients were divided into two groups with respect to subjective memory complaints and into two groups with respect to memory performance on the Fuld Object Memory Evaluation.Measurements: The percentage of individuals with memory complaints who also had objective memory impairment and the percentage of individuals with objective memory impairment who also complained about their memory were measured.Results: One‐tenth (10.6%) (95% confidence interval (CI)=7.7–14.7) of community based sample of 75‐year‐old subjects complained about their memory. There was no difference between complainers and noncomplainers with regard to actual memory performance. Only 6.3% (95% CI=0.16–30.2) of memory‐impaired subjects complained about their proven memory impairment.Conclusion: About 94% (95% CI=69.8–99.8) of memory‐impaired individuals do not complain about memory problems. Subjective memory complaints may not be a useful feature in current diagnostic criteria of mild cognitive impairment.