bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinematics of Intracellular Chlamydiae Provide Evidence for Contact-Dependent Development
Authors: Wilson David P. , Whittum-Hudson Judith A. , Timms Peter , Bavoil Patrik M. 
Published: June 2009

ABSTRACT

A crucial process of chlamydial development involves differentiation of the replicative reticulate body (RB) into the infectious elementary body (EB). We present experimental evidence to provide support for a contact-dependent hypothesis for explaining the trigger involved in differentiation. We recorded live-imaging of
Chlamydia trachomatis
-infected McCoy cells at key times during development and tracked the temporospatial trajectories of individual chlamydial particles. We found that movement of the particles is related to development. Early to mid-developmental stages involved slight wobbling of RBs. The average speed of particles increased sharply at 24 h postinfection (after the estimated onset of RB to EB differentiation). We also investigated a penicillin-supplemented culture containing EBs, RBs, and aberrantly enlarged, stressed chlamydiae. Near-immobile enlarged particles are consistent with their continued tethering to the chlamydial inclusion membrane (CIM). We found a significantly negative, nonlinear association between speed and size/type of particles, providing further support for the hypothesis that particles become untethered near the onset of RB to EB differentiation. This study establishes the relationship between the motion properties of the chlamydiae and developmental stages, whereby wobbling RBs gradually lose contact with the CIM, and RB detachment from the CIM is coincidental with the onset of late differentiation.
Genetic Analysis of Activation of the
Vibrio cholerae
Cpx Pathway
Authors: Slamti Leyla , Waldor Matthew K. 
Published: June 2009

ABSTRACT

The Cpx two-component system is thought to mediate envelope stress responses in many gram-negative bacteria and has been implicated in the pathogenicity of several enteric pathogens. While cues that activate the
Escherichia coli
Cpx system have been identified, the nature of the molecular signals that stimulate this pathway is not well understood. Here, we investigated stimuli that trigger this system in
Vibrio cholerae
, a facultative pathogen that adapts to various niches during its life cycle. In contrast to
E. coli
, there was no basal activity of the
V. cholerae
Cpx pathway under standard laboratory conditions. Furthermore, several known stimuli of the
E. coli
pathway did not induce expression of this system in
V. cholerae
. There were no defects in intestinal growth in
V
.
cholerae cpx
mutants, arguing against the idea that this pathway promotes
V
.
cholerae
adaptation to conditions in the mammalian host. We discovered that chloride ions activate the
V. cholerae
Cpx pathway, raising the possibility that this signal transduction system provides a means for
V. cholerae
to sense and respond to alterations in salinity. We used a genetic approach to screen for mutants in which the Cpx pathway is activated. We found that mutations in genes whose products are required for periplasmic disulfide bond isomerization result in activation of the Cpx pathway, suggesting that periplasmic accumulation of proteins with aberrant disulfide bonds triggers the
V. cholerae
Cpx pathway.
igr
Genes and
Mycobacterium tuberculosis
Cholesterol Metabolism
Authors: Chang Jennifer C. , Miner Maurine D. , Pandey Amit K. , Gill Wendy P. , Harik Nada S. , Sassetti Christopher M. , Sherman David R. 
Published: June 2009

ABSTRACT

Recently, cholesterol was identified as a physiologically important nutrient for
Mycobacterium tuberculosis
survival in chronically infected mice. However, it remained unclear precisely when cholesterol is available to the bacterium and what additional bacterial functions are required for its metabolism. Here, we show that the
igr
locus, which we previously found to be essential for intracellular growth and virulence of
M
.
tuberculosis
, is required for cholesterol metabolism. While
igr
-deficient strains grow identically to the wild type in the presence of short- and long-chain fatty acids, the growth of these bacteria is completely inhibited in the presence of cholesterol. Interestingly, this mutant is still able to respire under cholesterol-dependent growth inhibition, suggesting that the bacteria can metabolize other carbon sources during cholesterol toxicity. Consistent with this hypothesis, we found that the growth-inhibitory effect of cholesterol in vitro depends on cholesterol import, as mutation of the
mce4
sterol uptake system partially suppresses this effect. In addition, the Δ
igr
mutant growth defect during the early phase of disease is completely suppressed by mutating
mce4
, implicating cholesterol intoxication as the primary mechanism of attenuation. We conclude that
M
.
tuberculosis
metabolizes cholesterol throughout infection.
Respiration of
Escherichia coli
Can Be Fully Uncoupled via the Nonelectrogenic Terminal Cytochrome
bd
-II Oxidase
Authors: Bekker M. , de Vries S. , Ter Beek A. , Hellingwerf K. J. , de Mattos M. J. Teixeira 
Published: June 2009

ABSTRACT

The respiratory chain of
Escherichia coli
is usually considered a device to conserve energy via the generation of a proton motive force, which subsequently may drive ATP synthesis by the ATP synthetase. It is known that in this system a fixed amount of ATP per oxygen molecule reduced (P/O ratio) is not synthesized due to alternative NADH dehydrogenases and terminal oxidases with different proton pumping stoichiometries. Here we show that P/O ratios can vary much more than previously thought. First, we show that in wild-type
E. coli
cytochrome
bo
, cytochrome
bd
-I, and cytochrome
bd-
II are the major terminal oxidases; deletion of all of the genes encoding these enzymes results in a fermentative phenotype in the presence of oxygen. Second, we provide evidence that the electron flux through cytochrome
bd-
II oxidase is significant but does not contribute to the generation of a proton motive force. The kinetics support the view that this system is as an energy-independent system gives the cell metabolic flexibility by uncoupling catabolism from ATP synthesis under non-steady-state conditions. The nonelectrogenic nature of cytochrome
bd-
II oxidase implies that the respiratory chain can function in a fully uncoupled mode such that ATP synthesis occurs solely by substrate level phosphorylation. As a consequence, the yield with a carbon and energy source can vary five- to sevenfold depending on the electron flux distribution in the respiratory chain. A full understanding and control of this distribution open new avenues for optimization of biotechnological processes.
Proteomic and Genomic Characterization of Highly Infectious
Clostridium difficile
630 Spores
Authors: Lawley Trevor D. , Croucher Nicholas J. , Yu Lu , Clare Simon , Sebaihia Mohammed , Goulding David , Pickard Derek J. , Parkhill Julian , Choudhary Jyoti , Dougan Gordon 
Published: June 2009

ABSTRACT

Clostridium difficile
, a major cause of antibiotic-associated diarrhea, produces highly resistant spores that contaminate hospital environments and facilitate efficient disease transmission. We purified
C. difficile
spores using a novel method and show that they exhibit significant resistance to harsh physical or chemical treatments and are also highly infectious, with <7 environmental spores per cm
2
reproducibly establishing a persistent infection in exposed mice. Mass spectrometric analysis identified ∼336 spore-associated polypeptides, with a significant proportion linked to translation, sporulation/germination, and protein stabilization/degradation. In addition, proteins from several distinct metabolic pathways associated with energy production were identified. Comparison of the
C. difficile
spore proteome to those of other clostridial species defined 88 proteins as the clostridial spore “core” and 29 proteins as
C. difficile
spore specific, including proteins that could contribute to spore-host interactions. Thus, our results provide the first molecular definition of
C. difficile
spores, opening up new opportunities for the development of diagnostic and therapeutic approaches.
Interspecies Signaling between
Veillonella atypica
and
Streptococcus gordonii
Requires the Transcription Factor CcpA
Authors: Johnson Bart P. , Jensen Benjamin J. , Ransom Eric M. , Heinemann Kimberly A. , Vannatta Kelley M. , Egland Kristi A. , Egland Paul G. 
Published: June 2009

ABSTRACT

Streptococcus gordonii
and
Veillonella atypica
, two early-colonizing members of the dental plaque biofilm, participate in a relationship that results in increased transcription of the
S. gordonii
gene
amyB
, encoding an α-amylase. We show that the transcription factor CcpA is required for this interspecies interaction.
Molecular profile of ductal carcinoma in situ of the breast inBRCA1andBRCA2germline mutation carriers
Authors: van der Groep P , van Diest P J , Menko F H , Bart J , de Vries E G E , van der Wall E 
Published: June 2009

Aims:Ductal carcinoma in situ (DCIS) is an established late precursor of sporadic invasive breast cancer and to a large extent parallels its invasive counterpart with respect to molecular changes and immunophenotype. Invasive breast cancers in germlineBRCA1andBRCA2mutation carriers have a distinct “basal” and “luminal” immunophenotype, respectively, but the immunophenotype of their precursor lesions has hardly been studied, and this was the aim of this study.Methods:DCIS lesions of 25 provenBRCA1and 9 provenBRCA2germline mutation carriers and their 22 and 6, respectively, accompanying invasive lesions were stained by immunohistochemistry for oestrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor (HER)2/neu, cytokeratin (CK)5/6, CK14, epidermal growth factor receptor (EGFR) and Ki67.Results:DCIS lesions inBRCA1mutation carriers were mostly of the basal molecular type with low ER/PR/HER2 expression, while they frequently expressed CK5/6, CK14 and EGFR, and were mostly grade 3 and highly proliferative. DCIS lesions inBRCA2mutation carriers were mostly of luminal molecular type with frequent expression of ER/PR, and infrequent expression of CK5/6, CK14 and EGFR, and they were mostly grade 3 and showed low proliferation. InBRCA1andBRCA2mutation carriers there was a high concordance between DCIS lesions and their concomitant invasive counterpart with regard to expression of individual markers as well as “molecular” subtype.Conclusions:Although the number of cases studied was low, DCIS lesions inBRCA1andBRCA2mutations carriers are usually of the basal and luminal molecular type, respectively, similar to their accompanying invasive cancers, thereby providing evidence that DCIS is a direct precursor lesion in these hereditary predisposed patients. This also suggests that crucial carcinogenetic events leading to these phenotypes in hereditary predisposed patients occur before the stage of invasion.
Detection of smear zone using micro-cone and electrical resistance probe
Authors: Shin Dong-Hyun , Lee Changho , Lee Jong-Sub , Lee Woojin 
Published: June 2009

The installation of a prefabricated vertical drain (PVD) using a mandrel results in soil disturbance adjacent to the PVD, which is known as the smear zone. The smear zone is investigated by a series of radial penetration tests including a micro-cone penetrometer and an electrical resistance probe in the clay specimen prepared in a large-scale chamber. The 5 mm diameter micro-cone penetrometer and the 2.1 mm diameter electrical resistance probe produce continuous soil strength and electrical resistivity profiles around the PVD. Almost-constant values of the cone tip resistance and electrical resistivity are measured within the undisturbed zone. The outer boundary of the smear zone is clearly defined by the locations where the deviations of the measured cone tip resistance and electrical resistivity from the constant values are observed. Significant changes in both measurements are observed in the smear zone with remarkably consistent patterns. The smear zone induced by the PVD installation using a rectangular mandrel has an elliptical shape and extends to approximately 3.2∼3.4 times the half-length of the mandrel and 5.3∼5.4 times the half-width of the mandrel.
Oxyhalogen–sulfur chemistry — Kinetics and mechanism of oxidation of methionine by aqueous iodine and acidified iodate
Authors: Chikwana Edward , Davis Bradley , Morakinyo Moshood K. , Simoyi Reuben H. 
Published: June 2009

The oxidation of methionine (Met) by acidic iodate and aqueous iodine was studied. Though the reaction is a simple two-electron oxidation to give methionine sulfoxide (Met–S=O), the dynamics of the reaction are, however, very complex, characterized by clock reaction characteristics and transient formation of iodine. In excess methionine conditions, the stoichiometry of the reaction was deduced to be IO3– + 3Met → I– + 3Met–S=O. In excess iodate, the iodide product reacts with iodate to give a final product of molecular iodine and a 2:5 stoichiometry: 2IO3– + 5Met + 2H+→ I2 + 5Met–S=O + H2O. The direct reaction of iodine and methionine is slow and mildly autoinhibitory, which explains the transient formation of iodine, even in conditions of excess methionine in which iodine is not a final product. The whole reaction scheme could be simulated by a simple network of 11 reactions.
Novel formation of isoxazoline N-oxide in addition to Michael adduct from the reaction of β-nitrostyrenes with 2-methoxyfuran — Experimental and theoretical studies
Authors: Itoh Kuniaki , Kishimoto Shigehisa , Sagi Kazuo 
Published: June 2009

2-Methoxyfuran reacts with β-nitrostyrenes to give Michael adducts. Interestingly, isoxazoline N-oxides were obtained in the reactions with β-nitrostyrenes possessing additional electron-withdrawing groups [COPh (2f) and CO2Et (2g)]. (Z)-Nitrostyrene (2g) gives trans-isoxazoline (4g) and (E)-nitrostyrene (2f) leads to the cis-form product 4f. We have used theoretical methods to investigate the mechanism and to probe the regio- and stereo-selectivity observed in the rearrangement and the Michael reactions. To account for the selectivity observed in these reactions, we examined the Fukui functions and located the transition states (TS) using density functional theory (DFT) calculations at the B3LYP/6–31G* level. The first step involves a nucleophilic attack by the α-carbon atom (C4) of the furan ring on the vinyl C-atom (C5) of the nitrostyrene part to give a zwitterionic intermediate (IN1). Fission of the C–O bond of the furan ring in the intermediate and ring closure via the oxygen atom (endo-O atom) of the nitro group gives the isoxazoline N-oxide. Alternatively, the intermediate (IN1) may be transformed into the Michael adduct by an intramolecular proton transfer mediated by the formation of a four-membered transition-state structure. The potential-energy barriers for these reactions had the following values: 5.1 kcal/mol for 2f and 17.0 kcal/mol for 2g′ (CO2Me) at the rearrangement step, and 41–49 kcal/mol for the proton-transfer step. The solvent effect in CHCl3 stabilized the electrophilic attack by 1–14 kcal/mol. DFT analysis of these reactions is in good agreement with the experimental results.
Early Christian Missionaries as Physicians Healing and its Cultural Value in the Greco-Roman Context
Authors: Bazzana Giovanni Battista 
Published: June 2009

AbstractQ 10 shows some features that equate Jesus' missionaries to Greco-Roman medical practitioners. Moreover, some early Christian texts developed the same imagery, accompanying it with some hints of social critique. Conversely, under the early empire, the prestige and the privileges of doctors, who had good patronage connections, were significantly increased through imperial legislation. The Christian choice of representing missionaries as physicians may be understood by employing the anthropological category of “mimesis”. This entailed a critique of the patronage system and, hence, it arguably won the Christian mission a part of its success in some sectors of the ancient society.
Religious Identity and the Gospel of Reconciliation A Central European View
Authors: Tomka Miklós 
Published: June 2009

AbstractReligion and religious identities have stronghold in the people's life and identity in Central and Eastern Europe. After the collapse of communism and with the disintegration of the previous unifying systems, societies entered modernity swiftly which include the process of individualization and self determination. All these led to fundamental identity crisis. With its promise of coherent values, religion has become a strong force. The social impact of different religious groups, Catholic, Orthodox, Protestants, and Islam are different. Reconciliation has to begin with the healing of the wounded identities. It has to begin with the recognition of one's sinfulness and the effort to overcome it through dependence in God.
Bediako of Africa: A Late 20th Century Outstanding Theologian and Teacher
Authors: Asamoah-Gyadu J. Kwabena 
Published: June 2009

AbstractKwame Bediako of the Akrofi-Christaller Memorial Institute of Theology, Mission and Culture based in Akropong-Akwapim in Ghana, was a stalwart in the field of African Christianity and Theology. He was called home to glory in June 2008 at the age of 63 years. Converted from atheism whilst studying for a doctorate degree in French and African literature at the University of Bordeaux in France, Bediako embraced a conservative evangelical faith. He went on to do a second PhD in Theology under the tutelage of Andrew F. Walls in Aberdeen. Bediako returned to Ghana in 1984 to found the then Akrofi-Christaller Memorial Center for Mission Research and Applied Theology. Through that initiative, now a fully accredited tertiary theological educational institute, Bediako pioneered a new way of doing theology through his emphasis on mother-tongue hermeneutics, oral or grassroots theology, and the study of primal religions as the sub-structure of Christian expression in the majority Two Thirds World. These ideas are outlined in his major publications, Theology and Identity, Christianity in Africa, Jesus of Africa, and the many forceful and insightful articles scattered in local and international journals in religion and theology. For many years to come, although living in glory, Bediako's evangelical intellectual heritage will continue as a leading reference point for all those seeking to understand Africa's place in the history of world Christianity.
Moving towards integrated public governance: improving service delivery through community engagement
Authors: Kernaghan Kenneth 
Published: June 2009

Community engagement for improved citizen-centred service is an important dimension of Integrated Service Delivery (ISD), which is in turn a central component of the movement towards Integrated Public Governance. The experience of such organizations as Centrelink and Service Canada can inform thinking and action on the community engagement activities of ISD organizations in general. Most of these organizations are at an early stage in the use of innovative approaches to community engagement, but many of them are well positioned to use their physical presence in local offices across their jurisdiction to enhance service delivery. This article examines eight ISD organizations in four countries as a basis for discussing such matters as the benefits and challenges of community engagement, the nature of the engagement, and the means by which these organizations have fostered it. For ISD organizations to leverage their community presence, they must collaborate with a wide variety of community stakeholders. Points for practitioners Integrated Service Delivery (ISD) organizations can leverage their physical presence in local communities to improve service for individual citizens. This community engagement activity can take the form of partnerships, consultations and contracts. The corporate level can support community engagement through administrative structures and processes and through training opportunities and learning tools. Each local office needs an appropriate measure of discretion and flexibility to adapt its engagement activities to the community's particular challenges and resources. The movement in public management towards Integrated Public Governance and the anticipated increase in the delivery of government services by private and third sector organizations point to the need for collaborative community engagement. There are significant barriers as well as benefits associated with the community engagement activities of ISD organizations.
Understanding modern transparency
Authors: Meijer Albert 
Published: June 2009

Proponents and opponents fiercely debate whether computer-mediated transparency has a positive effect on trust in the public sector. This article enhances our understanding of transparency by presenting three perspectives: a premodern, modern and post-modern perspective, and analyzing the basic assumptions of these perspectives about transparency. The analysis shows that the proponents of computer-mediated transparency have a modern perspective on societal change: computer-mediated transparency gives people better information and thus contributes to the rationalization of society. Opponents argue from a premodern perspective that unidirectional, structured and decontextualized forms of transparency will result in a loss of societal trust. Postmodernists focus on the esthetics of transparency and argue for varied and diverse forms of computer-mediated transparency. The value of these three perspectives is illustrated by using them to analyze debates about the need for making school performance in the Netherlands transparent. On the basis of this analysis, the author argues for diversity in systems of transparency to maximize effects on societal trust. Points for practitioners This article evaluates transparency through the Internet from different perspectives. Premodernists see computer-mediated transparency as a threat to traditional mechanisms of trust such as face-to-face contacts, modernists praise computer-mediated transparency for its contribution to trust by providing objective information to the general public and postmodernists value the esthetic value of computer-mediated transparency. The ambivalent relation between trust and openness is at the heart of debates about the new transparency. This article argues that it is imperative that we understand these controversies, and debate which forms of computer-mediated transparency we want in the public sector.