bluuebunny/crossref_metadata_2025_split huggingface dataset:
Activation of the Cpx Envelope Stress Response Down-Regulates Expression of Several Locus of Enterocyte Effacement-Encoded Genes in Enteropathogenic
Escherichia coli
Authors: MacRitchie Dawn M. , Ward Jordan D. , Nevesinjac Anna Z. , Raivio Tracy L. 
Published: January 2008

ABSTRACT

The Cpx two-component system regulates an extracytoplasmic stress response that functions to rid the envelope of misfolded and mislocalized proteins that may interfere with normal cellular processes. The Cpx pathway is also involved in pathogenesis. This study investigated the role of the Cpx response in enteropathogenic
Escherichia coli
(EPEC) type III secretion (T3S). It was determined that a functional Cpx pathway is not required for T3S but that pathway activation inhibits secretion by reducing the cellular pools of T3S substrates. The EPEC T3S system structural components, as well as a number of its substrates, are encoded on the locus of enterocyte effacement (LEE) pathogenicity island. Transcriptional fusions to the five major operons of the LEE were constructed and examined under Cpx pathway-activating conditions. Induction of the Cpx response caused a decrease in the transcription of several LEE operons, with the most pronounced effect on LEE4 and LEE5. Collectively, these two operons encode components of the T3S translocation apparatus, the bacterial adhesin intimin, and the translocated bacterial receptor Tir. These data show for the first time that activation of the Cpx envelope stress response in EPEC inhibits T3S of both translocators and effectors, likely through down regulation of LEE transcription. Coupled with recent findings, our results suggest that Cpx-mediated down regulation of virulence is a conserved theme in a number of bacterial pathogens.
Role of Cyclic Di-GMP during El Tor Biotype
Vibrio cholerae
Infection: Characterization of the In Vivo-Induced Cyclic Di-GMP Phosphodiesterase CdpA
Authors: Tamayo Rita , Schild Stefan , Pratt Jason T. , Camilli Andrew 
Published: January 2008

ABSTRACT

In
Vibrio cholerae
, the second messenger cyclic di-GMP (c-di-GMP) positively regulates biofilm formation and negatively regulates virulence and is proposed to play an important role in the transition from persistence in the environment to survival in the host. Herein we describe a characterization of the infection-induced gene
cdpA
, which encodes both GGDEF and EAL domains, which are known to mediate diguanylate cyclase and c-di-GMP phosphodiesterase (PDE) activities, respectively. CdpA is shown to possess PDE activity, and this activity is regulated by its inactive degenerate GGDEF domain. CdpA inhibits biofilm formation but has no effect on colonization of the infant mouse small intestine. Consistent with these observations,
cdpA
is expressed during in vitro growth in a biofilm but is not expressed in vivo until the late stage of infection, after colonization has occurred. To test for a role of c-di-GMP in the early stages of infection, we artificially increased c-di-GMP and observed reduced colonization. This was attributed to a significant reduction in
toxT
transcription during infection. Cumulatively, these results support a model of the
V. cholerae
life cycle in which c-di-GMP must be down-regulated early after entering the small intestine and maintained at a low level to allow virulence gene expression, colonization, and motility at appropriate stages of infection.
Fcγ Receptor Regulation of
Citrobacter rodentium
Infection
Authors: Masuda Atsuhiro , Yoshida Masaru , Shiomi Hideyuki , Ikezawa Satoshi , Takagawa Tetsuya , Tanaka Hiroshi , Chinzei Ryo , Ishida Tsukasa , Morita Yoshinori , Kutsumi Hiromu , Inokuchi Hideto , Wang Shuo , Kobayashi Kanna , Mizuno Shigeto , Nakamura Akira , Takai Toshiyuki , Blumberg Richard S. , Azuma Takeshi 
Published: January 2008

ABSTRACT

Citrobacter rodentium
, a murine model pathogen for enteropathogenic
Escherichia coli
, colonizes the colon utilizing attaching and effacing lesions to adhere specifically to the surfaces of intestinal epithelial cells and cause mucosal inflammation. CD4
+
T cells, B cells, and immunoglobulin G (IgG), but not secretory IgA or IgM, play a critical role in eradicating this pathogen. Consistent with the importance of IgG in
C
.
rodentium
eradication, IgG transport by the neonatal Fc receptor for IgG within the intestinal epithelium also has a critical role in the regulation of
C
.
rodentium
infection. It remains to be determined, however, whether Fcγ receptors (FcγRs), the receptors for the Fc portion of IgG, regulate this bacterial infection within mucosal tissues. Therefore, we investigated the roles of FcγRs during
C
.
rodentium
infection. Fc receptor common gamma chain (FcRγ)-deficient mice were more susceptible to
C
.
rodentium
-induced colitis. This occurred through decreased efficiency of FcR-mediated endocytosis and maturation of dendritic cells and consequently T-cell activation of antigen-specific T cells. Moreover, in the absence of FcγRs, phagocytosis by macrophages was significantly diminished. Therefore, activating FcγRs play an important role in defending against
C
.
rodentium
infection, indicating that the critical role played by IgG in this infection is not mediated by IgG alone but is dependent upon this class of receptors.
The
Listeria monocytogenes
Virulence Factor InlJ Is Specifically Expressed In Vivo and Behaves as an Adhesin
Authors: Sabet Christophe , Toledo-Arana Alejandro , Personnic Nicolas , Lecuit Marc , Dubrac Sarah , Poupel Olivier , Gouin Edith , Nahori Marie-Anne , Cossart Pascale , Bierne Hélène 
Published: January 2008

ABSTRACT

The food-borne pathogen
Listeria monocytogenes
is adapted to a diversity of environments, such as soil, food, body fluids, and the cytosol of eukaryotic cells. The transition between saprophytic and pathogenic life is mediated through complex regulatory pathways that modulate the expression of virulence factors. Here we examined the expression of
inlJ
, a recently identified gene encoding a protein of the LPXTG-internalin family and involved in pathogenesis. We show that
inlJ
expression is controlled neither by the major listerial regulator of virulence genes, PrfA, nor by AxyR, a putative AraC regulator encoded by a gene adjacent to
inlJ
and divergently transcribed. The InlJ protein is not produced by bacteria grown in vitro in brain heart infusion medium or replicating in the cytosol of tissue-cultured cells. In contrast, it is efficiently produced and localized at the surface of bacteria present in the liver and blood of infected animals. Strikingly, the expression of
inlJ
by a heterologous promoter in
L
.
monocytogenes
or
L
.
innocua
promotes bacterial adherence to human cells in vitro. Taken together, these results strongly suggest that InlJ acts as a novel
L
.
monocytogenes
sortase-anchored adhesin specifically expressed during infection in vivo.
Role of age stratification for colposcopy referral following initial diagnosis of mild dyskaryosis
Authors: Crowther S , Turner L , Magee D , Gibbons D 
Published: January 2008

Introduction:Referral to colposcopy following a single mildly dyskaryotic smear is becoming more widely recommended in the developed world. This has workload and cost implications.Aim:To investigate if stratification of mildly dyskaryotic smears by age group might allow selection of populations that could be followed by repeat cytology initially.Methods:The study set was of all women with a diagnosis of dyskaryosis between July 2004 and June 2005 in an opportunistic screening programme. The dyskaryosis was divided into high grade (moderate and severe) and low grade and ratios of high to low grade were calculated for age groups. The age intervals were under 20 years, and every 5 years from 20 to 54 years.Results:In the study period, a total of 34 180 cervical smears were examined. Of these, 2326 women were diagnosed with dyskaryosis, (1566 (67%) low grade, 760 (33%) high grade) in the given age groups. This gave an overall ratio of high grade to low grade of 1:2. Ratios of high-grade dyskaryosis to low-grade dyskaryosis stayed relatively constant throughout the age intervals from 20 to 54 years of age, Pearson correlation coefficient 0.91, p = 0.0014.Conclusion:The ratios of incidences of grades of dyskaryosis remained constant throughout the age intervals suggesting that selective patterns of referral to colposcopy based on patient’s age at diagnosis of mild dyskaryosis are not applicable.
Cervical cytology biobanking: quality of DNA from archival cervical Pap-stained smears
Authors: Boulet G A V , Horvath C A J , Berghmans S , Moeneclaey L M , Duys I S M , Arbyn M , Depuydt C E , Vereecken A J , Sahebali S , Bogers J J 
Published: January 2008

Aims:Cervical cytology biobanking is a feasible concept in cervical pathology and could be an indispensable tool for fundamental and applied molecular biological research. PCR is a powerful molecular technique that can be performed on a variety of cervical sample types including Pap-stained cervical smears. However, since the quality of DNA from such specimens is inferior to that from fresh tissue, the correct processing methods are required. This study evaluates three commercial isolation methods and one digestion procedure for their ability to obtain DNA suitable for PCR from fixed and stained Pap smears.Methods:The High Pure PCR Template Preparation kit, the NucliSENS easyMAG system, the QIAamp DNA Mini Kit and crude proteinase K digestion were used to obtain DNA for subsequent PCR applications. Amplification of β-globin was performed to verify the presence and integrity of target DNA. The influence of PCR inhibitors and extent of DNA fragmentation were analysed.Results:All commercial DNA isolation techniques provided DNA suitable for PCR amplification, and DNA isolated from 10-year-old archival smears yielded amplicons up to 400 base pairs. Conversely, crude proteinase K digestion limited the amplicon size to 300 bp and did not consistently yield amplifiable digests, as these were contaminated with PCR-inhibiting factors and debris.Conclusion:The study indicates that commercial DNA isolation techniques are suitable for PCR amplification of DNA isolated from archival smears, yielding amplicons up to 400 base pairs. Proteinase K digestion is not suitable to obtain amplifiable DNA from fixed and stained Pap-stained smears.
Transition from CK-MB to troponin did not improve the 1 year mortality of non-ST elevation acute coronary syndromes
Authors: Novack V , Jotkowitz A B , Cutlip D , Amit G , Liebermann N , Porath A 
Published: January 2008

Abstract

Objective
To examine the hypothesis that transition from creatine kinase MB subunits (CK-MB) to troponin as a more sensitive biomarker of myocardial necrosis reduced the 1 year mortality of non-ST elevation acute coronary syndrome (ACS) patients.

Design
Retrospective population based cohort study performed in seven tertiary care hospitals in Israel. The patient population comprised all non-ST elevation ACS admissions during a 5 year period (1999–2004). CK-MB was the biomarker for the diagnosis of myocardial infarction (MI) at the time of admission in 14 037 patients (group 1), while 11 643 patients were admitted after the individual hospital laboratory switched to troponin (group 2). Incidence of ACS types, in-hospital management and 1 year survival was assessed.

Results
Group 2 patients had a higher frequency of non-ST elevation MI diagnosis (27.9% vs 17.7%, p&lt;0.001) and were more likely to undergo coronary catheterisation during hospitalisation (44.5% vs 37.5%, p&lt;0.001). One year mortality in non-ST elevation MI was lower in group 2 compared to group 1 (24.6% vs 28.1%, p = 0.002). Similarly, the 1 year death rate in the unstable angina group decreased in group 2 compared to group 1 (7.7% vs 8.5%, p = 0.04). However, the overall non-ST elevation ACS 1 year mortality rate did not change (12.4% vs 11.9%, p = 0.27). In multivariate Cox proportional hazard analysis the transition from CK-MB to troponin had no significant effect on overall 1 year mortality (hazard ratio 0.95, 95% confidence interval 0.89 to 1.03).

Conclusions
Transition to troponin as a diagnostic marker of MI led to an increase in the incidence of non-ST elevation MI. This transition was not associated with a decrease in the 1 year non-ST elevation ACS mortality rate.
Neurogenic orthostatic hypotension: chasing “the fall”
Authors: Gupta D , Nair M D 
Published: January 2008

Abstract
Orthostatic hypotension (OH) is a frequently encountered problem affecting nearly 30% of the population aged more than 60 years. It can result from neurological and non-neurological derangements which compromise the perfusion of the brain in an erect posture. Neurogenic OH is a manifestation of autonomic failure. It is an important cause of recurrent falls in the elderly, syncopal events and also has been shown to be associated with increased long term mortality from vascular and non-vascular causes. This review will discuss the pathophysiology, aetiology, clinical features and management of neurogenic OH and its differentiation from OH caused by non-neurological causes at each step. A clinician should primarily look for any reversible causes in a patient with neurogenic OH and should not forget that treatment is aimed at restoring the functioning capability of the patient rather than normotension. Co-existent supine hypertension in some patients should be taken into account while treating them.
Description of Diplogastrellus gracilis (Bütschli, 1876) Paramonov, 1952, D. sikorai sp. n. and Fictor composticola sp. n. (Nematoda: Diplogastrina) from India
Authors: Tahseen Qudsia , Khan Rahmat , Sultana Razia , Bajaj Harish 
Published: January 2008

AbstractTwo new diplogastrid species, Diplogastrellus sikorai sp. n. and Fictor composticola sp. n., are described and illustrated. Another species, D. gracilis, is reported for the first time from India and is redescribed with an emended diagnosis and SEM details. Diplogastrellus sikorai sp. n. is characterised by relatively small-sized body (female: L = 0.49-0.65 mm, a = 24-30, b = 4.9-6.3, c = 2.4-2.8), with a prominent, upright, dagger-like dorsal tooth and well developed subventral ridge; pore-like vulva, large post-uterine sac; ventrally arcuate spicules with rounded capitula and rosethorn-shaped gubernaculum with proximal spur and lateral sleeves around the spicules. Fictor composticola sp. n. is characterised by medium-sized body, eight cheilostomal plates with 18-22 cheilostomal filaments; gymnostom and stegostom with serrated anterior margins; dorsal and right subventral stegostomal walls each bearing a more or less equal tooth; left subventral stegostomal wall with two adjacent serrated plates; males with weakly cephalated, slender, ventrally arcuate spicules; wedge-shaped gubernaculum with tapering proximal end and lateral sleeves surrounding the distal ends of the spicules; and nine pairs of caudal papillae.
Unfiltering of the Geostationary Earth Radiation Budget (GERB) Data. Part I: Shortwave Radiation
Authors: Clerbaux N. , Dewitte S. , Bertrand C. , Caprion D. , De Paepe B. , Gonzalez L. , Ipe A. , Russell J. E. , Brindley H. 
Published: January 2008

Abstract
The method used to estimate the unfiltered shortwave broadband radiance from the filtered radiances measured by the Geostationary Earth Radiation Budget (GERB) instrument is presented. This unfiltering method is used to generate the first released edition of the GERB-2 dataset. The method involves a set of regressions between the unfiltering factor (i.e., the ratio of the unfiltered and filtered broadband radiances) and the narrowband observations of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) instrument. The regressions are theoretically derived from a large database of simulated spectral radiance curves obtained by radiative transfer computations. The generation of the database is fully described.
Different sources of error that may affect the GERB unfiltering have been identified and the associated error magnitudes are assessed on this database. For most of the earth–atmosphere conditions, the error introduced during the unfiltering process is below 1%. In some conditions (e.g., low sun elevation above the horizon) the error can present a higher relative value, but the absolute error value remains well under the accuracy goal of 1% of the full instrument scale (2.4 W m−2 sr−1).
To increase the confidence level, the edition 1 unfiltered radiances of GERB-2 are validated by cross comparison with collocated and coangular Clouds and the Earth’s Radiant Energy System (CERES) observations for different scene types. In addition to an overall offset between the two instruments, the intercomparisons indicate a scene-type dependency up to 4% in unfiltered radiance. Further studies are required to confirm the cause, but an insufficiently accurate characterization of the shortwave spectral response of the GERB instrument in the visible part of the spectrum is one area under further investigation.
Aerosol Impacts on the Diurnal Cycle of Marine Stratocumulus
Authors: Sandu Irina , Brenguier Jean-Louis , Geoffroy Olivier , Thouron Odile , Masson Valery 
Published: January 2008

Abstract
Recent large-eddy simulation (LES) studies of the impact of aerosol on the dynamics of nocturnal marine stratocumulus revealed that, depending on the large-scale forcings, an aerosol-induced increase of the droplet concentration can lead to either an increase or a decrease of the liquid water path, hence contrasting with the cloud thickening that is expected from a reduction of the precipitation efficiency. In this study, the aerosol impacts on cloud microphysics are examined in the context of the boundary-layer diurnal cycle using 36-h LES simulations of pristine and polluted clouds. These simulations corroborate previous findings that during nighttime aerosol-induced liquid water path changes are sensitive to the large-scale forcings via enhancement of cloud-top entrainment such that, ultimately, the liquid water path may be reduced when the free-tropospheric-entrained air is drier. During the day, however, enhanced entrainment, inhibition of drizzle evaporation below cloud base, and reduced sensible heat flux from the surface lead to a more pronounced decoupling of the boundary layer, which significantly amplifies the liquid water path reduction of the polluted clouds. At night the sign of the liquid water path difference between pristine and polluted clouds depends upon large-scale forcings, while during the day the liquid water path of polluted clouds is always smaller than the one of the pristine clouds. Suggestions are made on how observational studies could be designed for validation of these simulations.
A Baroclinic Laminar State for Rotating Stratified Flows
Authors: Sun Che 
Published: January 2008

Abstract
A baroclinic laminar model is developed as the late-time equilibrium state in the free decay of rotating stratified turbulence under low-Froude-number scaling. Vertical motions are suppressed by stratification and ambient rotation, and in the laminar end state the flow assumes a quasi-two-dimensional form. Geometric analyses of this nonlinear conservative model reveal an f-plane baroclinic topology characterized by vertical alignment, vanishing nonlinearity, and the complete absence of helicity. Equivalent-barotropic flow is the only nonunique baroclinic solution, and its horizontal topology is restricted to a unidirectional jet and a circular vortex. Such a depleted geometry results from the constraint of basic equations where density is advected as an active scalar. It provides a baroclinic mechanism for the formation of coherent structures in geophysical flows.
Consequences of Considering Carbon–Nitrogen Interactions on the Feedbacks between Climate and the Terrestrial Carbon Cycle
Authors: Sokolov Andrei P. , Kicklighter David W. , Melillo Jerry M. , Felzer Benjamin S. , Schlosser C. Adam , Cronin Timothy W. 
Published: January 2008

Abstract
The impact of carbon–nitrogen dynamics in terrestrial ecosystems on the interaction between the carbon cycle and climate is studied using an earth system model of intermediate complexity, the MIT Integrated Global Systems Model (IGSM). Numerical simulations were carried out with two versions of the IGSM’s Terrestrial Ecosystems Model, one with and one without carbon–nitrogen dynamics.
Simulations show that consideration of carbon–nitrogen interactions not only limits the effect of CO2 fertilization but also changes the sign of the feedback between the climate and terrestrial carbon cycle. In the absence of carbon–nitrogen interactions, surface warming significantly reduces carbon sequestration in both vegetation and soil by increasing respiration and decomposition (a positive feedback). If plant carbon uptake, however, is assumed to be nitrogen limited, an increase in decomposition leads to an increase in nitrogen availability stimulating plant growth. The resulting increase in carbon uptake by vegetation exceeds carbon loss from the soil, leading to enhanced carbon sequestration (a negative feedback). Under very strong surface warming, however, terrestrial ecosystems become a carbon source whether or not carbon–nitrogen interactions are considered.
Overall, for small or moderate increases in surface temperatures, consideration of carbon–nitrogen interactions result in a larger increase in atmospheric CO2 concentration in the simulations with prescribed carbon emissions. This suggests that models that ignore terrestrial carbon–nitrogen dynamics will underestimate reductions in carbon emissions required to achieve atmospheric CO2 stabilization at a given level. At the same time, compensation between climate-related changes in the terrestrial and oceanic carbon uptakes significantly reduces uncertainty in projected CO2 concentration.
Ocean Forcing to Changes in Global Monsoon Precipitation over the Recent Half-Century
Authors: Zhou Tianjun , Yu Rucong , Li Hongmei , Wang Bin 
Published: January 2008

Abstract
Previous examination of changes in global monsoon precipitation over land reveals an overall weakening over the recent half-century (1950–2000). The present study suggests that this significant change in global land monsoon precipitation is deducible from the atmosphere’s response to the observed SST variations. When forced by historical sea surface temperatures covering the same period, the ensemble simulation with the NCAR Community Atmosphere Model, version 2 (CAM2) model successfully reproduced the weakening tendency of global land monsoon precipitation. This decreasing tendency was mainly caused by the warming trend over the central-eastern Pacific and the western tropical Indian Ocean. At the interannual time scale, the global land monsoon precipitation is closely correlated with ENSO. The simulated interannual variation of the global land monsoon index matches well with the observation, indicating that most monsoon precipitation variations arise from the ocean forcing. There are uncertainties between the GPCP and the CMAP data in describing the evolution of global ocean monsoon precipitation. There is very little correspondence between the simulated and the observed global monsoon index over the ocean area. Uncertainties in the satellite data and model deficiencies in describing the ocean monsoon domain are partly to blame. Among the components of global monsoon systems, the Asian–Australian monsoon system has the lowest reproducibility with prescribed SST forcing due to the neglect of air–sea feedback.