bluuebunny/crossref_metadata_2025_split huggingface dataset:
Muralytic activity of Micrococcus luteus Rpf and its relationship to physiological activity in promoting bacterial growth and resuscitation
Authors: Mukamolova Galina V. , Murzin Alexey G. , Salina Elena G. , Demina Galina R. , Kell Douglas B. , Kaprelyants Arseny S. , Young Michael 
Published: October 2005

SummaryThe culturability of several actinobacteria is controlled by resuscitation‐promoting factors (Rpfs). These are proteins containing a c. 70‐residue domain that adopts a lysozyme‐like fold. The invariant catalytic glutamate residue found in lysozyme and various bacterial lytic transglycosylases is also conserved in the Rpf proteins. Rpf from Micrococcus luteus, the founder member of this protein family, is indeed a muralytic enzyme, as revealed by its activity in zymograms containing M. luteus cell walls and its ability to (i) cause lysis of Escherichia coli when expressed and secreted into the periplasm; (ii) release fluorescent material from fluorescamine‐labelled cell walls of M. luteus; and (iii) hydrolyse the artificial lysozyme substrate, 4‐methylumbelliferyl‐β‐d‐N,N′,N′′‐triacetylchitotrioside. Rpf activity was reduced but not completely abolished when the invariant glutamate residue was altered. Moreover, none of the other acidic residues in the Rpf domain was absolutely required for muralytic activity. Replacement of one or both of the cysteine residues that probably form a disulphide bridge within Rpf impaired but did not completely abolish muralytic activity. The muralytic activities of the Rpf mutants were correlated with their abilities to stimulate bacterial culturability and resuscitation, consistent with the view that the biological activity of Rpf results directly or indirectly from its ability to cleave bonds in bacterial peptidoglycan.
The chaperone binding domain of SopE inhibits transport via flagellar and SPI‐1 TTSS in the absence of InvB
Authors: Ehrbar Kristin , Winnen Brit , Hardt Wolf‐Dietrich 
Published: October 2005

SummaryType III secretion systems (TTSS) are used by many Gram‐negative pathogens for transporting effector proteins into eukaryotic host cells. Two modes of type III effector protein transport can be distinguished: transport into the surrounding medium (secretion) and cell‐contact induced injection of effector proteins directly into the host cell cytosol (translocation). Two domains within the N‐terminal regions of effector proteins determine the mode of transport. The amino terminal ∼20 amino acids (N‐terminal secretion signal, NSS) mediate secretion. In contrast, translocation generally requires the NSS, the adjacent ∼100 amino acids (chaperone binding domain, CBD) and binding of the cognate chaperone to this CBD. TTSS are phylogenetically related to flagellar systems. Because both systems are expressed in Salmonella Typhimurium, correct effector protein transport involves at least two decisions: transport via the Salmonella pathogenicity island 1 (SPI‐1) but not the flagellar TTSS (= specificity) and translocation into the host cell instead of secretion into the surrounding media (= transport mode). The mechanisms guiding these decisions are poorly understood. We have studied the S. Typhimurium effector protein SopE, which is specifically transported via the SPI‐1 TTSS. Secretion and translocation strictly require the cognate chaperone InvB. Alanine replacement of amino acids 30–42 (and to some extent 44–54) abolished tight InvB binding, abolished translocation into the host cell and led to secretion of SopE via both, the flagellar and the SPI‐1 TTSS. In clear contrast to wild‐type SopE, secretion of SopEAla30‐42 and SopEAla44‐54 via the SPI‐1 and the flagellar export system did not require InvB. These data reveal a novel function of the CBD: the CBD inhibits secretion of wild‐type SopE via the flagellar and the SPI‐1 TTSS in the absence of the chaperone InvB. Our data provide new insights into mechanisms ensuring specific effector protein transport by TTSS.
Identification of the central quorum sensing regulator of virulence in the enteric phytopathogen, Erwinia carotovora: the VirR repressor
Authors: Burr Tom , Barnard Anne M. L. , Corbett Mark J. , Pemberton Clare L. , Simpson Natalie J. L. , Salmond George P. C. 
Published: October 2005

SummaryIn the Gram‐negative phytopathogen, Erwinia carotovora ssp. atroseptica (Eca) virulence depends on the production of a N‐(3‐oxohexanoyl)‐l‐homoserine lactone (OHHL) quorum sensing (QS) signal. This work identifies the elusive ‘missing link’ between QS and virulence in Erwinia. We have identified and characterized a novel regulator of virulence, VirR, in Eca and show that a virR mutation completely restores virulence factor production to an Eca mutant unable to synthesize OHHL. This effect of the virR mutation translates to a restoration of virulence to wild‐type levels and thus provides evidence that VirR acts to prevent the production of virulence factors at low cell density. We also show that, in Eca, transcription of virulence genes is controlled by OHHL and that this control is effected through the action of VirR. We also demonstrate that the VirR regulatory pathway is present and functional in both blackleg and soft rotting species of Erwinia.
Virulence and drug resistance roles of multidrug efflux systems of Salmonella enterica serovar Typhimurium
Authors: Nishino Kunihiko , Latifi Tammy , Groisman Eduardo A. 
Published: October 2005

SummaryDrug efflux systems play a major role in resistance to a wide range of noxious compounds in several Gram negative species. Here, we report the drug resistance and virulence phenotypes of Salmonella mutants defective in either resistance‐nodulation‐division (RND)‐type systems and/or in drug efflux systems belonging to the major facilitator (MFS), multidrug and toxic compound extrusion (MATE), and ATP‐binding cassette (ABC) superfamilies. We determined that nine potential drug transporters contribute to drug resistance of Salmonella and found that the Salmonella‐specific MdsABC system conferred resistance to a variety of toxic compounds. The RND‐type MdsAB system could function with either MdsC, which is encoded in the same operon, or TolC as the outer membrane component. Although the Salmonella EmrAB, MdfA and MdtK are 90% identical in their amino acid sequences to their Escherichia coli homologues, the drug specificity of Salmonella transporters was different from that reported for equivalent E. coli transporters. Deletion of the macAB genes attenuated Salmonella virulence and a strain lacking all drug efflux systems was avirulent when mice were inoculated by the oral route. The promoter region of the macAB drug efflux system genes harbours a binding site for the response regulator PhoP, which functions to repress macAB transcription. The PhoP/PhoQ two‐component system is a major regulator of Salmonella virulence, which underscores the connection between drug efflux systems and virulence.
A small RNA inhibits translation of the histone‐like protein Hc1 in Chlamydia trachomatis
Authors: Grieshaber Nicole A. , Grieshaber Scott S. , Fischer Elizabeth R. , Hackstadt Ted 
Published: October 2005

SummaryThe chromatin of chlamydial elementary bodies (EBs) is stabilized by proteins with sequence homology to eukaryotic H1. These histone homologues, termed Hc1 and Hc2, are expressed only during the late stages of the chlamydial life cycle concomitant with the reorganization of reticulate bodies (RBs) into metabolically inactive EBs. Hc1 and Hc2 play a major role in establishment of nucleoid structure as well as in downregulation of gene expression as RBs differentiate back to EBs. The effects of Hc1 on gene expression patterns requires that chlamydiae strictly control Hc1 activity. Hc1 expression and activity are thus regulated transcriptionally as well as post‐transcriptionally. We describe here a small regulatory RNA (sRNA) that acts as an additional checkpoint to negatively regulate Hc1 synthesis. Coexpression of the sRNA with hctA, the gene that encodes Hc1, in Escherichia coli inhibited Hc1 translation but did not affect hctA mRNA transcription or stability. IhtA (inhibitor of hctA translation) was present only in purified RBs while Hc1 was present only in purified EBs. During infection IhtA, but not Hc1, was present in RBs and was downregulated while Hc1 was upregulated upon RB to EB differentiation. Thus, we propose that IhtA is part of a global regulatory circuit that controls differentiation of RBs to EBs during the chlamydial life cycle.
Hypothalamic‐pituitary gonadal axis and immune response imbalance during chronic filarial infections
Authors: Mavoungou Donatien , Poaty‐Mavoungou Virginie , Ongali Brice , Akoume Marie Yvonne , Maka Gontran , Mavoungou Elie 
Published: October 2005

SummaryBi‐directional relationships operate between the hypothalamic‐pituitary‐gonadal axis and the immune system. Cytokines, peptide hormones and their shared receptors/ligands are used as a common biological language for communication within and between the immune and neuroendocrine systems. Such communication suggests an immunoregulatory role for the brain and a sensory function for the immune system. We used a radioimmunoassay to measure the concentrations of steroid hormones (cortisol, testosterone, estradiol and progesterone) and pituitary hormones [follicle stimulating hormone (FSH), luteinizing hormone (LH) human chorionic gonadotropin (HCG) and prolactin] in peripheral blood plasma from 78 young Gabonese women with chronic filarial infections. We used an enzyme‐linked immunosorbent assay to determine the concentrations of four proinflammatory cytokines [tumor necrosis factor‐alpha (TNF‐α), gamma interferon (IFN‐γ), interleukin‐1 (IL‐1) and IL‐6] in the same plasma samples. Progesterone was unchanged and all other steroid hormone plasma concentrations were lower in microfilaremic women than in amicrofilaremic women. The concentration of LH was higher in amicrofilaremic women, whereas the prolactin concentration was higher in microfilaremics. The plasma concentrations of TNF‐α, IFN‐γ, IL‐1 and IL‐6 were higher in microfilaremic women. A strong negative correlation was found between the steroid and pituitary hormones and the pro‐inflammatory cytokines. Conversely, a strong positive correlation was found between prolactin and the same cytokines. These data provide first evidence of immune system and hormonal system disturbance during chronic filarial infections and suggest that the observed imbalance should be taken into account in the diagnosis and treatment of filarial infections.
Cytokine and Ig‐production by CG‐containing sequences with phosphorodiester backbone and dumbbell‐shape
Authors: Schmidt M. , Anton K. , Nordhaus C. , Junghans C. , Wittig B. , Worm M. 
Published: October 2005

Background:  Immunostimulatory oligodeoxynucleotides (CpG‐ODN) usually contain phosphorothioate (PS) backbones for nucleotide protection, which may result in some nonspecific side‐effects like prolongation of coagulation time.Objective:  The aim of the present study was to investigate the immunomodulatory potential of DNA molecules without PS backbones. Thus, we designed phosphorodiester (PO) molecules with a dumbbell‐like covalently‐closed structure (dSLIM‐30L1).Methods:  We analyzed their effects on peripheral blood mononuclear cells (PBMC) from spontaneous high and low immunoglobulin (Ig)E producer (allergic and nonallergic donors) in comparison with linear CpG‐ODN (lin‐30L1) with PS backbones, using enzyme‐linked immunosorbent assay and flow cytometry.Results:  We observed a decrease of spontaneous IgE levels in PBMC from high IgE producer of approximately 27% with both dSLIM‐30L1 and lin‐30L1. In addition, both molecules enhanced the production of IgA, IgM and IgG1/IgG2, but with a slightly different pattern. Both molecules stimulated the secretion of the TH1‐like cytokines interleukin (IL)‐2, interferon‐γ and IL‐12p40 and the pro‐inflammatory cytokine IL‐6. The immunomodulatory potential of dSLIM‐30L1 and lin‐30L1 was also effective in PBMC from nonallergic donors, as was confirmed for IL‐2, IL‐12p40, IgG1/IgG2 and IgM.Conclusion:  Our data show an inhibition of IgE production but also enhancement of the inflammatory cytokine response in PBMC from allergic and nonallergic donors by covalently‐closed PO‐based dSLIM‐30L1 with a pattern similar to that of linear PS‐based lin‐30L1, while avoiding PS‐modifications and thus PS‐mediated side‐effects. Whether such molecules are useful for the treatment of allergic diseases will need further clarification by appropriate in vivo studies.
Dietary intake in sensitized children with recurrent wheeze and healthy controls: a nested case–control study
Authors: Murray C. S. , Simpson B. , Kerry G. , Woodcock A. , Custovic A. 
Published: October 2005

Background:  The rising prevalence of asthma and allergic disease remains unexplained. Several risk factors have been implicated including diet, in particular poly‐unsaturated fats and antioxidant intake.Methods:  A nested case–control study comparing the dietary intake of sensitized children with recurrent wheeze (age 3–5 years) and nonsensitized children who had never wheezed was carried out within an unselected population‐based cohort. Cases and controls were matched for age, sex, parental atopy, indoor allergen exposure and pet ownership. Dietary intake was assessed using a validated semi‐quantitative food frequency questionnaire and nutrient analysis program.Results:  Thirty‐seven case–control pairs (23 male, mean age 4.4 years) participated. Daily total polyunsaturated fat intake was significantly higher in sensitized wheezers (g/day, geometric mean, 95% confidence intervals: 7.1, 6.4–7.9) compared with nonsensitized nonwheezy children (5.6, 5.0–6.3, P = 0.003). Daily omega‐3 and omega‐6 fat intakes were not significantly different between the two groups. No significant differences were found in intake of any antioxidant or antioxidant cofactors between the groups.Conclusions:  Young sensitized wheezy children had a significantly higher total polyunsaturated fat intake compared with nonsensitized nonwheezy children. However, we were unable to distinguish a significant difference in specific poly‐unsaturated fat intakes. Otherwise the children in both groups had a very similar nutritional intake.
Comparison of X‐ray vs. gamma irradiation of CPDA‐1 red cells
Authors: Janatpour K. , Denning L. , Nelson K. , Betlach B. , MacKenzie M. , Holland P. 
Published: October 2005

Background and Objectives  Transfusion‐associated graft‐versus‐host disease (TA‐GVHD) is a serious, potential complication of blood transfusion that is essentially prevented by blood product irradiation. Blood product irradiation is currently performed using gamma irradiation. X‐ray irradiation is an alternative that has certain advantages: an X‐ray irradiator is less expensive and does not have a radioactive source. However, the biochemical effects of X‐ray irradiation on red blood cells (RBCs) have not been well characterized. The primary purpose of our study was to compare the effects of X‐ray irradiation with gamma irradiation on RBC membrane permeability. A secondary purpose was to verify that X‐ray irradiation has the same effect on lymphocytes as gamma irradiation.Materials and Methods  Ten RBC units were split into two portions; five units of each were then irradiated with either gamma or X‐ray at a dose of 35 Gy or 25 Gy, respectively. Free plasma haemoglobin and extracellular potassium levels were measured in each unit over time. Another unit was divided into three parts for lymphocyte studies; one part was not irradiated as a control and the other two received 25 Gy of irradiation via X‐ray or gamma irradiation, respectively.Results  Minimally increased free plasma haemoglobin was found only in X‐ray‐irradiated units after 25 Gy compared to gamma‐irradiated units. However, extracellular potassium levels were not significantly different in these groups. Extracellular potassium levels were slightly higher only in gamma irradiated units at 35 Gy. X‐ray and gamma irradiation were equivalent in affecting lymphocyte function.Conclusions  Small differences in RBC membrane permeability are found between gamma‐irradiated and X‐ray‐irradiated units. However, these differences are not likely to be clinically important.
“Poetry? Of course we do it. It's in the National Curriculum.” Primary children's perceptions of poetry
Authors: Kelly Alison 
Published: October 2005

AbstractWhat can listening to children's ideas about poetry teach us? This article considers ways in which exploring primary‐aged students' perceptions of poetry can inform teachers' work with children. Using strategies from earlier studies in secondary schools, a small‐scale project with Year 6 students revealed their complex and sometimes contradictory ideas. These ideas reflect some of the current debates around the nature of poetry and ways of teaching it. The children's ideas are analysed with critical attention paid to the impact of the view of literacy in England's National Literacy Strategy on the teaching and learning of poetry.
Beginning readers' use of talking books: styles of working
Authors: Wood Clare , Littleton Karen , Chera Pav 
Published: October 2005

AbstractThis paper examines young children's working styles when they are engaged with a peer on a computer‐based reading task. Two types of pairing were investigated: (i) ‘Equal’ pairs, where the children were of equal reading attainment and (ii) ‘Unequal pairs’, where there was a disparity between the children's reading attainment. The results suggest that the children's reading attainment and/or their gender may be more significant factors in determining the nature of children's collaborative activity than pair type. The implications of these results for practitioners who wish to use talking books as a classroom resource are discussed.
THE ROLE OF HOUSE PRICES IN THE MONETARY TRANSMISSION MECHANISM ACROSS EUROPEAN COUNTRIES
Authors: Giuliodori Massimo 
Published: October 2005

AbstractThis paper provides a discussion of the ‘housing market’ channels of the monetary transmission mechanism and offers some evidence of institutional differences in the European housing and mortgage markets. Using a number of Vector Autoregressive models, estimated individually for nine European countries over the pre‐EMU period, we find that house prices are significantly affected by interest rate shocks. The relative role of these interest‐rate‐induced fluctuations in house prices for private consumption is then investigated. We show that house prices may enhance the effects of interest rate shocks on consumer spending in those economies where housing and mortgage markets are relatively more developed and competitive.
Authority Concepts Among Children and Adolescents in the Island of Macao
Authors: Laupa Marta , Tse Pamela 
Published: October 2005

AbstractWe examined the reasoning of children and adolescents in the island of Macao regarding the bases of legitimate authority across social contexts. We asked 101 children in 3rd, 5th, and 7th grades to evaluate the authority of persons issuing commands to children in two events. In one, persons with varying combinations of authority attributes issue a command that resolves a turn‐taking dispute between children in school. In another, persons with varying social positions issue a command to children to stop playing ball across three contexts: school, home, and a public park. Results show that, although young Macanese reason in many ways similar to American children, social position may be a less important legitimizing authority attribute for them than for American children.
What Do Grandmothers Think about Self‐esteem? American and Taiwanese Folk Theories Revisited
Authors: Cho Grace E. , Sandel Todd L. , Miller Peggy J. , Wang Su‐hua 
Published: October 2005

AbstractThe study investigates European American and Taiwanese grandmothers’ folk theories of childrearing and self‐esteem, building on an earlier comparison of mothers from the same families. Adopting methods that privilege local meanings, we bring grandmothers’ voices into the conversation about childrearing, thereby contributing to a deeper understanding of intergenerational nuances in folk theories. In each cultural case, 16 grandmothers of 3‐year‐olds participated in in‐depth interviews that were customized according to local communicative norms. Although self‐esteem emerged as a central organizing concept in the folk theories of European American mothers, grandmothers spoke in two voices, either echoing their daughters or invoking a counter‐discourse of wariness towards self‐esteem. By contrast, Taiwanese mothers and grandmothers resembled one another—but differed from their American counterparts—in treating self‐esteem as peripheral in childrearing. Results contribute to the growing consensus that self‐esteem is a culture‐specific childrearing goal and suggest that the European American tendency to valorize self‐esteem varies by generation.
Multilevel Modelling of the Number of Property Crimes: Household and Area Effects
Authors: Tseloni Andromachi 
Published: October 2005

SummaryThis study examines household and area effects on the incidence of total property crimes and burglaries and thefts. It uses data from the 2000 British Crime Survey and the 1991 UK census small area statistics. Results are obtained from estimated random-effects multilevel models, with an assumed negative binomial distribution of the dependent variable. Both household and area characteristics, as well as selected interactions, explain a significant portion of the variation in property crimes. There are also a large number of significant between-area random variances and covariances of household characteristics. The estimated fixed and random effects may assist in advancing victimization theory. The methods have potential for developing a better understanding of factors that give rise to crime and so assist in framing crime prevention policy.
A Bayesian Hierarchical Model for Categorical Longitudinal Data from a Social Survey of Immigrants
Authors: Pettitt A. N. , Tran T. T. , Haynes M. A. , Hay J. L. 
Published: October 2005

SummaryThe paper investigates a Bayesian hierarchical model for the analysis of categorical longitudinal data from a large social survey of immigrants to Australia. Data for each subject are observed on three separate occasions, or waves, of the survey. One of the features of the data set is that observations for some variables are missing for at least one wave. A model for the employment status of immigrants is developed by introducing, at the first stage of a hierarchical model, a multinomial model for the response and then subsequent terms are introduced to explain wave and subject effects. To estimate the model, we use the Gibbs sampler, which allows missing data for both the response and the explanatory variables to be imputed at each iteration of the algorithm, given some appropriate prior distributions. After accounting for significant covariate effects in the model, results show that the relative probability of remaining unemployed diminished with time following arrival in Australia.